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Search Results (267)

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16 pages, 4410 KiB  
Article
Effects of Ecological Restoration Measures on Growth Renewal and Nutritional Quality of Arundinaria faberi in Degraded Habitat of Giant Panda
by Weirui Qin, Jingyi Liu, Han Pan, Yong Cheng, Xinqiang Song, Mingxia Fu, Yuanbin Zhang, Xiaofeng Luan and Biao Yang
Forests 2024, 15(12), 2241; https://doi.org/10.3390/f15122241 - 20 Dec 2024
Viewed by 268
Abstract
Restoring the degraded habitat of the giant panda (Ailuropoda melanoleuca) is of paramount importance for the conservation of the species and its forest ecosystem. However, little is known about the impact of ecological restoration interventions on the growth renewal and nutritional [...] Read more.
Restoring the degraded habitat of the giant panda (Ailuropoda melanoleuca) is of paramount importance for the conservation of the species and its forest ecosystem. However, little is known about the impact of ecological restoration interventions on the growth renewal and nutritional quality of Arundinaria faberi in the degraded habitat of the giant panda. Here, we implemented strip thinning and blocky thinning techniques in the Daxiangling mountain range, alongside a control group. A random forest model and multiple linear regression analysis were employed to predict changes in the growth renewal and nutritional quality of bamboo, particularly in the strip-thinned zones. The key findings were as follows: (1) Compared with the control area, strip thinning increased the number of shoots and increased the diameter and height of shoots. (2) The random forest model predicted a decline in bamboo regeneration indices in 2023 compared to 2022 under strip thinning. (3) Through thinning, the palatability and nutritional level of A. faberi were improved. (4) Long-term effects included increased tannin in leaves, decreased tannin and amino acids in shoots and culms, and increased crude fat, with changes in crude protein distribution across bamboo parts. Overall, these findings provide valuable insights for habitat restoration efforts targeting giant panda populations in the low-canopy forest ecosystems of the Daxiangling mountain range. Full article
(This article belongs to the Section Forest Biodiversity)
Show Figures

Figure 1

Figure 1
<p>Location of the study area in the Yingjing area of GPNP and spatial distribution of the quadrats. The position of the Yingjing area of GPNP is labeled in the figure.</p>
Full article ">Figure 2
<p>Schematic diagram of <span class="html-italic">Arundinaria faberi</span> thinning in restoration sites on slopes of Daxiangling mountain range.</p>
Full article ">Figure 3
<p>Photographs of monitoring bamboo quadrats under different treatments (strip thinning, blocky thinning, and control group from left to right).</p>
Full article ">Figure 4
<p>Boxplots for growth renewal changes of <span class="html-italic">A. faberi</span> under different ecological restoration measures in different year–month. Note: Abnormal value are represented by dots in the figure. “Bamboo counts” and “Shoots counts” stand for the number of bamboo per quadrat, and the number of shoots per quadrat.</p>
Full article ">Figure 5
<p>Scatter plot of prediction results of growth renewal of <span class="html-italic">A. faberi</span> under strip thinning. Note: The red dashed line represents the line of perfect prediction or the line of equality.</p>
Full article ">Figure 6
<p>Comparison of nutrient content of different components of <span class="html-italic">A. faberi</span> under different treatment methods. Plot (<b>a</b>): Comparison of tannin content of different components of <span class="html-italic">A. faberi</span> under different treatment methods; Plot (<b>b</b>): Comparison of crude fat content of different components of <span class="html-italic">A. faberi</span> under different treatment methods; Plot (<b>c</b>): Comparison of amino acid content of different components of <span class="html-italic">A. faberi</span> under different treatment methods; Plot (<b>d</b>): Comparison of crude protein content of different components of <span class="html-italic">A. faberi</span> under different treatment methods. Note: AL, annual leaves; DL, perennial leaves; S, shoots; AP, annual culms; DP, perennial culms. Confidence Interval is depicted by grayed area around the trend lines in the diagrams.</p>
Full article ">Figure 6 Cont.
<p>Comparison of nutrient content of different components of <span class="html-italic">A. faberi</span> under different treatment methods. Plot (<b>a</b>): Comparison of tannin content of different components of <span class="html-italic">A. faberi</span> under different treatment methods; Plot (<b>b</b>): Comparison of crude fat content of different components of <span class="html-italic">A. faberi</span> under different treatment methods; Plot (<b>c</b>): Comparison of amino acid content of different components of <span class="html-italic">A. faberi</span> under different treatment methods; Plot (<b>d</b>): Comparison of crude protein content of different components of <span class="html-italic">A. faberi</span> under different treatment methods. Note: AL, annual leaves; DL, perennial leaves; S, shoots; AP, annual culms; DP, perennial culms. Confidence Interval is depicted by grayed area around the trend lines in the diagrams.</p>
Full article ">Figure 7
<p>The regression trend diagram of nutrient content of bamboo. Note: AL, annual leaves; DL, perennial leaves; S, shoots; AP, annual culms; DP, perennial culms. Confidence Interval is depicted by grayed area around the trend lines in the diagrams.</p>
Full article ">
27 pages, 10850 KiB  
Article
Modal Analysis with Asymptotic Strips Boundary Conditions of Skewed Helical Gratings on Dielectric Pipes as Cylindrical Metasurfaces for Multi-Beam Holographic Rod Antennas
by Malcolm Ng Mou Kehn, Ting-Wei Lin and Wei-Chuan Chen
Sensors 2024, 24(24), 8119; https://doi.org/10.3390/s24248119 - 19 Dec 2024
Viewed by 244
Abstract
A core dielectric cylindrical rod wrapped in a dielectric circular pipe whose outer surface is enclosed by a helical conducting strip grating that is skewed along the axial direction is herein analyzed using the asymptotic strip boundary conditions along with classical vector potential [...] Read more.
A core dielectric cylindrical rod wrapped in a dielectric circular pipe whose outer surface is enclosed by a helical conducting strip grating that is skewed along the axial direction is herein analyzed using the asymptotic strip boundary conditions along with classical vector potential analysis. Targeted for use as a cylindrical holographic antenna, the resultant field solutions facilitate the aperture integration of the equivalent cylindrical surface currents to obtain the radiated far fields. As each rod section of a certain skew angle exhibits a distinct modal attribute; this topology allows for the distribution of the cylindrical surface impedance via the effective refractive index to be modulated, as in gradient-index (GRIN) materials. Beam steering can also be achieved by altering the skew angle via mechanical sliding motion while leaving the cylindrical structure itself unchanged, as opposed to impractically reconfiguring the geometrical and material parameters of the latter to attain each new beam direction. The results computed by the program code based on the proposed technique in terms of the modal dispersion and radiation patterns are compared with simulations by a software solver. Manufactured prototypes are measured, and experimentally acquired dispersion diagrams and radiation patterns are favorably compared with theoretical predictions. Full article
Show Figures

Figure 1

Figure 1
<p>Perspective schematic view of skewed helical conducting strip-grating printed on outer surface of dielectric pipe wrapped over core dielectric rod.</p>
Full article ">Figure 2
<p>Lateral view of helical conducting strip-grating with skew angle Φ printed on outer surface of dielectric pipe with outer radius <span class="html-italic">b</span> and of medium (<span class="html-italic">ε<sub>out</sub></span>, <span class="html-italic">μ<sub>out</sub></span>) wrapped over core dielectric rod with radius <span class="html-italic">a</span> and of medium (<span class="html-italic">ε<sub>in</sub></span>, <span class="html-italic">μ<sub>in</sub></span>). Axes showing coordinate transformation as shown.</p>
Full article ">Figure 3
<p>Modal dispersion diagrams for <span class="html-italic">m</span> = 1, <span class="html-italic">a</span> = 3 mm, <span class="html-italic">b</span> = 6 mm, (<span class="html-italic">μ<sub>in</sub></span>, <span class="html-italic">ε<sub>in</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 2.2<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>out</sub></span>, <span class="html-italic">ε<sub>out</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 3.8<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>ext</sub></span>, <span class="html-italic">ε<sub>ext</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, <span class="html-italic">ε</span><sub>0</sub>), computed by presented ASBC-based analysis and simulated by CST, for (<b>a</b>) Φ = 5°, (<b>b</b>) Φ = 10°, (<b>c</b>) Φ = 15°, (<b>d</b>) Φ = 20°, (<b>e</b>) Φ = 25°, (<b>f</b>) Φ = 30°, (<b>g</b>) Φ = 35°, (<b>h</b>) Φ = 40°.</p>
Full article ">Figure 4
<p>Modal dispersion diagrams for <span class="html-italic">m</span> = 1, <span class="html-italic">a</span> = 3 mm, <span class="html-italic">b</span> = 6 mm, (<span class="html-italic">μ<sub>in</sub></span>, <span class="html-italic">ε<sub>in</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 2.2<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>out</sub></span>, <span class="html-italic">ε<sub>out</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 3.8<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>ext</sub></span>, <span class="html-italic">ε<sub>ext</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, <span class="html-italic">ε</span><sub>0</sub>), for various Φ (5°, 10°, 20°, and 30°), (<b>a</b>) computed by code according to ASBC-based analysis, and (<b>b</b>) simulated by CST.</p>
Full article ">Figure 5
<p>Modal dispersion diagrams for <span class="html-italic">a</span> = 1 mm, <span class="html-italic">b</span> = 10 mm, (<span class="html-italic">μ<sub>in</sub></span>, <span class="html-italic">ε<sub>in</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 2<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>out</sub></span>, <span class="html-italic">ε<sub>out</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 2.25<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>ext</sub></span>, <span class="html-italic">ε<sub>ext</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, <span class="html-italic">ε</span><sub>0</sub>), Φ = 1°, computed by presented ASBC-based analysis (asterisk markers) and by likewise ASBC-based method for treating corresponding conventional transverse circumferential metal circular strip grated rod (dot markers), as well as simulated by CST (circle markers).</p>
Full article ">Figure 6
<p>Real and imaginary parts of eigenvector coefficients: (<b>a</b>) <span class="html-italic">C</span><sub>13</sub>, (<b>b</b>) <span class="html-italic">C</span><sub>14</sub>, and (<b>c</b>) <span class="html-italic">C</span><sub>15</sub>, plotted versus effective refractive index <span class="html-italic">n<sub>eff</sub></span> = <span class="html-italic">β<sub>z</sub><sup>univ</sup></span>/<span class="html-italic">k</span><sub>0</sub>, each pertaining to a Φ. Original solved ones of (14) given by circle markers, and reconstructed by polynomial curve-fitting with degree <span class="html-italic">N</span> = 6 (crosses), as of (58), for <span class="html-italic">m</span> = 1, <span class="html-italic">f<sub>reson</sub></span> = 14 GHz, <span class="html-italic">a</span> = 3 mm, <span class="html-italic">b</span> = 6 mm, (<span class="html-italic">μ<sub>in</sub></span>, <span class="html-italic">ε<sub>in</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 2.2<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>out</sub></span>, <span class="html-italic">ε<sub>out</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 3.8<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>ext</sub></span>, <span class="html-italic">ε<sub>ext</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, <span class="html-italic">ε</span><sub>0</sub>).</p>
Full article ">Figure 7
<p>Normalized real and imaginary parts of surface impedance tensor elements: (<b>a</b>) Re(<span class="html-italic">Z<sub>ϕϕ</sub></span>), (<b>b</b>) Im(<span class="html-italic">Z<sub>ϕϕ</sub></span>), (<b>c</b>) Re(<span class="html-italic">Z<sub>ϕz</sub></span>), (<b>d</b>) Im(<span class="html-italic">Z<sub>ϕz</sub></span>), (<b>e</b>) Re(<span class="html-italic">Z<sub>zϕ</sub></span>), (<b>f</b>) Im(<span class="html-italic">Z<sub>zϕ</sub></span>), (<b>g</b>) Re(<span class="html-italic">Z<sub>zz</sub></span>), (<b>h</b>) Im(<span class="html-italic">Z<sub>zz</sub></span>), contour plotted versus effective refractive index <span class="html-italic">n<sub>eff</sub></span> = <span class="html-italic">β<sub>z</sub><sup>univ</sup></span>/<span class="html-italic">k</span><sub>0</sub> and <span class="html-italic">z</span>, for single TE beam towards <span class="html-italic">θ</span><sub>0<span class="html-italic">e</span></sub> = 60°, rod length of 300 mm, with <span class="html-italic">m</span> = 1, <span class="html-italic">f<sub>reson</sub></span> = 14 GHz, <span class="html-italic">a</span> = 3 mm, <span class="html-italic">b</span> = 6 mm, (<span class="html-italic">μ<sub>in</sub></span>, <span class="html-italic">ε<sub>in</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 2.2<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>out</sub></span>, <span class="html-italic">ε<sub>out</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 3.8<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>ext</sub></span>, <span class="html-italic">ε<sub>ext</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, <span class="html-italic">ε</span><sub>0</sub>).</p>
Full article ">Figure 8
<p>Contour plot of base-10 logarithm, log<sub>10</sub>|<span class="html-italic">F</span>(<span class="html-italic">n<sub>eff</sub></span>, <span class="html-italic">z</span>)|, of LHS function of characteristic equation in (59), versus <span class="html-italic">n<sub>eff</sub></span> and <span class="html-italic">z</span>, for dual beam case of <span class="html-italic">θ</span><sub>0<span class="html-italic">m</span></sub> = 40° (TM) and <span class="html-italic">θ</span><sub>0<span class="html-italic">e</span></sub> = 65° (TE), with rod length of 300 mm, with <span class="html-italic">m</span> = 1, <span class="html-italic">f<sub>reson</sub></span> = 14 GHz, <span class="html-italic">a</span> = 3 mm, <span class="html-italic">b</span> = 6 mm, (<span class="html-italic">μ<sub>in</sub></span>, <span class="html-italic">ε<sub>in</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 2.2<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>out</sub></span>, <span class="html-italic">ε<sub>out</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 3.8<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>ext</sub></span>, <span class="html-italic">ε<sub>ext</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, <span class="html-italic">ε</span><sub>0</sub>); (<b>a</b>) planar top view, and (<b>b</b>) perspective view.</p>
Full article ">Figure 9
<p>Polynomially curve-fitted graph of <span class="html-italic">n<sub>eff</sub></span> vs. <span class="html-italic">X<sub>TM</sub></span> according to (64).</p>
Full article ">Figure 10
<p>Graph of <span class="html-italic">n<sub>eff</sub></span> vs. skew angle Φ.</p>
Full article ">Figure 11
<p>Graph of <span class="html-italic">n<sub>eff</sub></span> vs. <span class="html-italic">z</span> according to (65).</p>
Full article ">Figure 12
<p>Graph of Φ vs. <span class="html-italic">z</span>.</p>
Full article ">Figure 13
<p>Radiation patterns of holographic rod antenna designed to radiate a single TM-polarized main beam towards <span class="html-italic">θ</span><sub>0<span class="html-italic">m</span></sub> = 60°, obtained by both solvers, with co-polar <span class="html-italic">E<sub>θ</sub></span> and cross-polar <span class="html-italic">E<sub>ϕ</sub></span> components separately plotted. Schematic of rod antenna shown inset. Maximum directivity = 8.241 dBi, |S<sub>11</sub>| = −14.7324 dB, realized gain = 8.0924 dBi. Radiation efficiency is −3.577 dB.</p>
Full article ">Figure 14
<p>Radiation pattern of holographic rod antenna designed to radiate a single TE-polarized main beam towards <span class="html-italic">θ</span><sub>0<span class="html-italic">m</span></sub> = 40° (realize 38°), obtained by both solvers, with co-polar <span class="html-italic">E<sub>ϕ</sub></span> and cross-polar <span class="html-italic">E<sub>θ</sub></span> components separately plotted. Schematic of rod antenna shown inset. Maximum directivity = 7.215 dBi, |S<sub>11</sub>| = −15.65 dB, realized gain = 7.0948 dBi. Radiation efficiency is −3.1724 dB.</p>
Full article ">Figure 15
<p>Radiation patterns of holographic rod antenna designed to radiate two TM-polarized beams towards <span class="html-italic">θ</span><sub>0<span class="html-italic">m</span>1</sub> = 35° and <span class="html-italic">θ</span><sub>0<span class="html-italic">m</span>2</sub> = 50°, obtained by both solvers, with co-polar <span class="html-italic">E<sub>θ</sub></span> and cross-polar <span class="html-italic">E<sub>ϕ</sub></span> components separately plotted. Schematic of rod antenna shown above the graph. Maximum directivities towards these two respective beam directions are 7.3 dBi and 6.8 dBi, |S<sub>11</sub>| = −18.1257 dB, respective realized gains = 7.23 dBi and 6.734 dBi. Radiation efficiency is −3.766 dB.</p>
Full article ">Figure 16
<p>Radiation patterns of holographic rod antenna designed to radiate two TE-polarized beams towards <span class="html-italic">θ</span><sub>0<span class="html-italic">e</span>1</sub> = 40° and <span class="html-italic">θ</span><sub>0<span class="html-italic">e</span>2</sub> = 60°, obtained by both solvers, with co-polar <span class="html-italic">E<sub>ϕ</sub></span> and cross-polar <span class="html-italic">E<sub>θ</sub></span> components separately plotted. Maximum directivities towards these two respective beam directions are 7.1055 dBi and 6.179 dBi, |S<sub>11</sub>| = −15.1757 dB, respective realized gains = 6.9716 dBi and 6.0452 dBi. Radiation efficiency is −2.507 dB.</p>
Full article ">Figure 17
<p>Contour plot of normalized surface wave modal wavenumber <span class="html-italic">β<sub>z</sub></span>/<span class="html-italic">k</span><sub>0</sub> at 14 GHz of spiral-grated rod with <span class="html-italic">a</span> = 3 mm, <span class="html-italic">b</span> = 6 mm, Φ = 29°, against relative permittivities (<span class="html-italic">ε<sub>in</sub></span>/<span class="html-italic">ε</span><sub>0</sub>, <span class="html-italic">ε<sub>out</sub></span>/<span class="html-italic">ε</span><sub>0</sub>).</p>
Full article ">Figure 18
<p>Photographs of the two manufactured prototypes of skewed helical copper wire gratings wound on dielectric pipe sheathed over core dielectric rod (the latter invisible); skew angles (<b>a</b>) 20° and (<b>b</b>) 30°. Close-up shot in (<b>c</b>) of grooves with appropriate tilt angles cut into rod surface for wire to be slotted firmly in place.</p>
Full article ">Figure 19
<p>(<b>a</b>) Schematic of the measurement setup, and (<b>b</b>) photograph of actual experimental scenario for measuring modal dispersion comprising a feed horn antenna and a coaxial probe connected respectively to ports 1 and 2 of a vector network analyzer (not included in the photograph).</p>
Full article ">Figure 20
<p>Measured modal dispersion traces of two manufactured helically grated rods of different skew angles compared with theoretical ones predicted by ASBC-based analysis and CST simulations as indicated in legends, both for <span class="html-italic">a</span> = 3 mm, <span class="html-italic">b</span> = 6 mm, (<span class="html-italic">μ<sub>in</sub></span>, <span class="html-italic">ε<sub>in</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 2.1<span class="html-italic">ε</span><sub>0</sub> ≈ 2.2<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>out</sub></span>, <span class="html-italic">ε<sub>out</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 3.8<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>ext</sub></span>, <span class="html-italic">ε<sub>ext</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, <span class="html-italic">ε</span><sub>0</sub>), for (<b>a</b>) Φ = 20°, and (<b>b</b>) Φ = 30°.</p>
Full article ">Figure 21
<p>Photographs of experimental setup in an anechoic chamber for measurements of far-field radiation patterns of the manufactured rods; (<b>a</b>) overall view of chamber showing feed horn and AUT (grated rod) on rotating platform at near end and receiving horn at far end, and (<b>b</b>) closed-up view of grated rod fed by feed horn.</p>
Full article ">Figure 22
<p>Measured normalized far-field radiation patterns of Φ = 30° rod for <span class="html-italic">a</span> = 3 mm, <span class="html-italic">b</span> = 6 mm, (<span class="html-italic">μ<sub>in</sub></span>, <span class="html-italic">ε<sub>in</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 2.1<span class="html-italic">ε</span><sub>0</sub> ≈ 2.2<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>out</sub></span>, <span class="html-italic">ε<sub>out</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 3.8<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>ext</sub></span>, <span class="html-italic">ε<sub>ext</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, <span class="html-italic">ε</span><sub>0</sub>), at (<b>a</b>) 13 GHz and (<b>b</b>) 14 GHz.</p>
Full article ">Figure 23
<p>Measured normalized far-field radiation patterns of Φ = 20° rod for <span class="html-italic">a</span> = 3 mm, <span class="html-italic">b</span> = 6 mm, (<span class="html-italic">μ<sub>in</sub></span>, <span class="html-italic">ε<sub>in</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 2.1<span class="html-italic">ε</span><sub>0</sub> ≈ 2.2<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>out</sub></span>, <span class="html-italic">ε<sub>out</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, 3.8<span class="html-italic">ε</span><sub>0</sub>), (<span class="html-italic">μ<sub>ext</sub></span>, <span class="html-italic">ε<sub>ext</sub></span>) = (<span class="html-italic">μ</span><sub>0</sub>, <span class="html-italic">ε</span><sub>0</sub>), at (<b>a</b>) 15 GHz and (<b>b</b>) 16 GHz.</p>
Full article ">Figure 24
<p>Measured normalized far-field radiation patterns of two holographic rod antennas, designed to radiate (<b>a</b>) a single beam towards <span class="html-italic">θ</span><sub>0<span class="html-italic">m</span></sub> = 60°, and (<b>b</b>) double beams towards <span class="html-italic">θ</span><sub>0<span class="html-italic">e</span>1</sub> = 40° and <span class="html-italic">θ</span><sub>0<span class="html-italic">e</span>2</sub> = 60°, both compared with computed ones.</p>
Full article ">
14 pages, 3314 KiB  
Article
CRISPR-Cas-Based Pen-Side Diagnostic Tests for Anaplasma marginale and Babesia bigemina
by Robert Muriuki, Maingi Ndichu, Samuel Githigia and Nicholas Svitek
Microorganisms 2024, 12(12), 2595; https://doi.org/10.3390/microorganisms12122595 - 15 Dec 2024
Viewed by 563
Abstract
Anaplasma marginale and Babesia bigemina are tick-borne pathogens, posing significant threats to the health and productivity of cattle in tropical and subtropical regions worldwide. Currently, detection of Babesia bigemina and Anaplasma marginale in infected animals relies primarily on microscopic examination of Giemsa-stained blood or [...] Read more.
Anaplasma marginale and Babesia bigemina are tick-borne pathogens, posing significant threats to the health and productivity of cattle in tropical and subtropical regions worldwide. Currently, detection of Babesia bigemina and Anaplasma marginale in infected animals relies primarily on microscopic examination of Giemsa-stained blood or organ smears, which has limited sensitivity. Molecular methods offer higher sensitivity but are costly and impractical in resource-limited settings. Following the development of a pen-side test for detecting Theileria parva infections in cattle, we have created two additional CRISPR-Cas12a assays targeting Anaplasma marginale and Babesia bigemina. The assays target the major surface protein 5 (MSP5) for A. marginale and rhoptry-associated protein 1a (RAP1a) for B. bigemina. These additional tests involve a 20 min recombinase polymerase amplification (RPA) reaction followed by a 60 min CRISPR-Cas12a detection with a lateral strip readout. Results demonstrate high specificity, with no cross-reactivity against other tick-borne parasites, and a limit of detection down to 102 DNA copies/µL of each target marker. The findings pave the way for sensitive and user-friendly pen-side tests to diagnose A. marginale and B. bigemina infections. Full article
(This article belongs to the Section Microbial Biotechnology)
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<p>Schematic representation of the steps taken in the development of the assays. Created in BioRender. Svitek, N. (2024) <a href="http://BioRender.com/a88f007" target="_blank">BioRender.com/a88f007</a>.</p>
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<p>Histogram representation of the flow cytometry-based readout for the specificity of the PCR/Cas12a assays using the single crRNA approach for (<b>a</b>) <span class="html-italic">A. marginale</span> and (<b>b</b>) <span class="html-italic">B. bigemina</span>.</p>
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<p>Flow cytometry readout for the sensitivity of the PCR-Cas12a assays. (<b>a</b>) Sensitivity of the <span class="html-italic">A. marginale</span> assay with a single crRNA (1), (<b>b</b>) Sensitivity of the <span class="html-italic">B. bigemina</span>-specific test with a single crRNA (1).</p>
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<p>Histogram representation of the flow cytometry-based readout for the specificity of the PCR-Cas12a assays using dual crRNAs for (<b>a</b>) <span class="html-italic">A. marginale</span> and (<b>b</b>) <span class="html-italic">B. bigemina</span>.</p>
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<p>Flow cytometry readout for the sensitivity of the PCR-Cas12a assays using two crRNAs per target gene. (<b>a</b>) Sensitivity of the <span class="html-italic">A. marginale</span> assay with dual crRNAs, (<b>b</b>) sensitivity of the <span class="html-italic">B. bigemina</span>-specific test with dual crRNAs.</p>
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<p>Specificity of the RPA-Cas12a assay for <span class="html-italic">Anaplasma marginale</span> and <span class="html-italic">Babesia bigemina</span> using the lateral flow readout format. (<b>a</b>) Lateral flow assay specificity for <span class="html-italic">A. marginale</span>: 1. <span class="html-italic">A. marginale</span> positive sample, 2. <span class="html-italic">B. bigemina</span>, 3. <span class="html-italic">T. parva</span>, 4. <span class="html-italic">T. mutans</span>, 5. <span class="html-italic">T. lestoquardi</span>, and 6. no template control. (<b>b</b>) Lateral flow strip assay specificity for <span class="html-italic">B. bigemina</span>: 7. <span class="html-italic">B. bigemina positive sample</span>, 8. <span class="html-italic">A. marginale</span>, 9. <span class="html-italic">T. parva</span>, 10. <span class="html-italic">T. mutans</span>, 11. <span class="html-italic">T. lestoquardi</span>, and 12. no template control.</p>
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<p>Sensitivity of the RPA-Cas12a assay for <span class="html-italic">Anaplasma marginale</span> and <span class="html-italic">Babesia bigemina</span>. (<b>a</b>) Lateral flow assay limit of detection for <span class="html-italic">Anaplasma marginale</span>: 1. 10<sup>3</sup> DNA copies/µL, 2. 10<sup>2</sup> DNA copies/µL, 3. 10<sup>1</sup> DNA copies/µL, 4. 10<sup>0</sup> DNA copies/µL, and NTC: no template control. (<b>b</b>) Lateral flow strip sensitivity for <span class="html-italic">B. bigemina</span>: 1. 10<sup>3</sup> DNA copies/µL, 2. 10<sup>2</sup> DNA copies/µL, 3. 10<sup>1</sup> DNA copies/µL, 4. 10<sup>0</sup> DNA copies/µL, and NTC: no template control.</p>
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<p>Sensitivity comparison between our test and other tests. (<b>a</b>) Sensitivity of other diagnostic tests for <span class="html-italic">Anaplasma marginale</span> and <span class="html-italic">Babesia bigemina</span> in comparison to our tests (light blue dot) [references taken from <a href="#microorganisms-12-02595-t003" class="html-table">Table 3</a> where data of copy numbers was available], and (<b>b</b>) other CRISPR-Cas diagnostic tests that use copy numbers as a measure of limit of detection: 42 copies/µL [<a href="#B20-microorganisms-12-02595" class="html-bibr">20</a>], 50 copies/µL [<a href="#B31-microorganisms-12-02595" class="html-bibr">31</a>], 50 copies/µL [<a href="#B32-microorganisms-12-02595" class="html-bibr">32</a>], 74 copies/µL [<a href="#B33-microorganisms-12-02595" class="html-bibr">33</a>], 94 copies/µL [<a href="#B34-microorganisms-12-02595" class="html-bibr">34</a>], 100 copies/µL [<a href="#B35-microorganisms-12-02595" class="html-bibr">35</a>], 100 copies/µL [<a href="#B36-microorganisms-12-02595" class="html-bibr">36</a>], 100 copies/µL [<a href="#B37-microorganisms-12-02595" class="html-bibr">37</a>], 100 copies/µL [<a href="#B38-microorganisms-12-02595" class="html-bibr">38</a>], 200 copies/µL [<a href="#B39-microorganisms-12-02595" class="html-bibr">39</a>], 200 copies/µL [<a href="#B40-microorganisms-12-02595" class="html-bibr">40</a>], and 250 copies/µL [<a href="#B41-microorganisms-12-02595" class="html-bibr">41</a>].</p>
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19 pages, 9284 KiB  
Article
Insights from Biophotonic Imaging and Biochemical Analysis on Cellular and Molecular Alterations Exhibited in Dull Skin
by Akira Matsubara, Tatsuya Omotezako, Ying Xu, Anna Evdokiou, Lijuan Li, Wenzhu Zhao, Camila Pereira Braga, Dionne Swift, Hitomi Nagasawa, Jennifer I. Byrd, Brad Jarrold, Gang Deng, Junjie Wang and Tomohiro Hakozaki
Cosmetics 2024, 11(6), 219; https://doi.org/10.3390/cosmetics11060219 - 12 Dec 2024
Viewed by 570
Abstract
Dullness or lack of radiance in facial appearance is a common concern among females. Previous studies have linked skin dullness to aging and revealed alterations in skin pigments. However, younger individuals (ages ≤ 35) also report concerns about dull skin in their hectic [...] Read more.
Dullness or lack of radiance in facial appearance is a common concern among females. Previous studies have linked skin dullness to aging and revealed alterations in skin pigments. However, younger individuals (ages ≤ 35) also report concerns about dull skin in their hectic daily lives, which may not involve pigmentation changes. We hypothesized that the mechanisms underlying dullness in youth differ from those associated with aging. To investigate this, we measured cellular and molecular changes in 132 healthy Japanese and Chinese females aged 18 to 35 using biophotonic multiphoton tomography and biochemical tape-strip analysis. Our findings revealed that dull skin exhibited a thicker stratum granulosum and less densely packed keratinocytes in deeper layers. Biochemical analysis showed upregulation of interleukin-36γ and downregulation of E-cadherin in dull skin, with interleukin-36γ levels negatively correlating (p = 0.023) with metabolites of filaggrin. These alterations resemble those observed in inflammatory skin conditions, suggesting an additional mechanism of skin dullness beyond pigmentation. In vitro cultured cell models evaluated the efficacy of three skincare ingredients: galactomyces fermentation filtrate, bisabolol, and batyl alcohol. Galactomyces suppressed interleukin-36γ (p = 0.037), while both batyl alcohol (p = 0.006) and bisabolol (p = 0.049) showed beneficial effects on filaggrin. Targeting these biomarkers may improve the appearance of dull skin. Full article
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<p>An overview of the DTIS. This is a custom-made facial imaging system to capture facial skin appearance under controlled and even illumination, and the images were utilized for the visual grading of radiance or dullness.</p>
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<p>Skin radiance/dullness grouping by visual grading. Ten untrained respondents performed the visual grading using DTIS images displayed on a color-calibrated monitor. The grading was conducted on a 10-point scale, where a higher score indicated greater radiance. In this figure, each point represents an individual subject (a person in the image), and the threshold between the two groups was the median score of the 11 subjects.</p>
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<p>Determination of the skin layer boundaries. The skin layer boundaries were determined based on visual examination of the MPT images. We identified four boundaries of the skin layers as depicted in the figure. Between points A and B, keratinocytes are denucleated and are cornified. We define these layers as the stratum granulosum in this article. The bottom of the epidermis is difficult to identify, so we defined it as the point intermediate between points C and D. Abbreviations: keratinocyte (KC), stratum corneum (SC), collagen (COL).</p>
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<p>The thickness of skin layers. (<b>a</b>) Stratum granulosum (SG) and (<b>b</b>) the rest of the epidermis. The duller skin group (<span class="html-italic">n</span> = 5) and the more radiant skin group (<span class="html-italic">n</span> = 6) were determined by visual grading as described in <a href="#cosmetics-11-00219-f002" class="html-fig">Figure 2</a>. In this measurement, one layer is equivalent to a thickness of 2.5 μm.</p>
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<p>The count of nuclei of keratinocytes. The nuclei of keratinocytes were observed using MPT imaging. Layer 0 corresponds to point B defined in <a href="#cosmetics-11-00219-f003" class="html-fig">Figure 3</a>, representing the bottom of the stratum granulosum layer. In this measurement, one layer is equivalent to a thickness of 2.5 μm. The asterisks(*) in the Figure indicate that the count of nuclei of radiant skin is statistically higher (<span class="html-italic">p</span> &lt; 0.05) than that of dull skin.</p>
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<p>Correlation between biomarkers and skin radiance. (<b>a</b>) IL-36γ and (<b>b</b>) CDH1. Radiance skin score was determined by visual grading.</p>
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<p>Correlations between IL-36γ and (<b>a</b>) PCA and (<b>b</b>) UCA. PCA and UCA are known metabolites of FLG. IL-36γ is known to be associated with psoriasis, in which the downregulation of FLG is observed. To determine whether the same pattern is seen in dull skin, we examined the correlation between IL-36γ and amino acids that are metabolites of FLG.</p>
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<p>Skin differences by IL-36γ Levels. The population was grouped by the median of IL-36γ levels. (<b>a</b>) Confirmatory figure to show the difference in IL-36γ in both groups, (<b>b</b>) TEWL, (<b>c</b>) Skin redness, and (<b>d</b>) Skin roughness.</p>
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<p>Effect of skincare materials on IL-36γ expression. (<b>a</b>) Effect of 5.0% GFF or 0.25% batyl alcohol. (<b>b</b>) Effect of 0.000625% bisabolol. HEKn cells at 70% confluence were treated with GFF, batyl alcohol, or bisabolol for 24 h. Total protein was extracted from the cells, quantified, and equal amounts of protein were assayed by ELISA.</p>
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<p>Effect of skincare materials on CDH1. HEKn cells at 70% confluence were treated with 5.0% GFF, 0.000625% bisabolol, or 0.25% batyl alcohol for 24 h. Total protein was extracted from the cells, quantified, and equal amounts of protein were assayed by ELISA.</p>
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<p>FLG staining (red) upon skincare materials treatment. The 3D skin equivalent cultures were topically treated for 5 days with 0.1% DMSO, 10% GFF, 0.005% bisabolol, or 0.25% batyl alcohol, and then immunofluorescently stained for FLG. Scale bar represents 100 μm.</p>
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<p>Effect of skincare materials on FLG. Quantification was conducted by FLG staining area (red) relative to DAPI nuclear staining area (blue) in <a href="#cosmetics-11-00219-f011" class="html-fig">Figure 11</a>.</p>
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16 pages, 4570 KiB  
Article
Design and Experiment of a PLC-Based Intelligent Thermal Insulation Box for Nursing Piglets
by Bin Sun, Hao Wang, Xuemin Pan, Yaqiong Zeng, Bin Hu, Renli Qi, Dingbiao Long and Shunlai Xu
Animals 2024, 14(24), 3580; https://doi.org/10.3390/ani14243580 - 11 Dec 2024
Viewed by 309
Abstract
Local heating of the activity area for nursing piglets is crucial for piglet health and the energy efficiency of barn climate control. Traditional heating methods using lamps or covers lack precise control, result in significant energy waste, and cannot be dynamically adjusted according [...] Read more.
Local heating of the activity area for nursing piglets is crucial for piglet health and the energy efficiency of barn climate control. Traditional heating methods using lamps or covers lack precise control, result in significant energy waste, and cannot be dynamically adjusted according to piglet age or changing environmental temperatures. To address these issues, this study designed a Programmable Logic Controller (PLC)-based thermal insulation box for nursing piglets, utilizing a strip heater instead of the conventional round heating lamp. The design incorporates a movable thermal insulation box that dynamically adjusts the heater’s power based on the real-time monitoring of environmental temperatures and target temperatures specific to piglet age. First, in a controlled laboratory environment, the study tested and compared the spatial temperature uniformity, temporal stability, and power consumption of the new thermal insulation box versus traditional heating methods. Subsequently, animal trials were conducted in a farrowing barn using eight sows with similar farrowing dates as test subjects. The new thermal insulation box was installed in one group, and the traditional heating lamp in the control group. During the trial, ambient temperature, insulation area temperature, piglet behavior, growth performance, and power consumption were recorded. The results showed that compared to the control group, the new system reduced average temperature fluctuations in the insulation area by 31.6% and spatial temperature variation by 78.3%. During animal trials, the average temperatures directly under the heater for the new system versus the control in the insulation area were 39.7 ± 0.2 °C and 30.2 ± 1.4 °C in the first week, 40.9 ± 0.5 °C and 31.6 ± 0.7 °C in the second week, and 32.3 ± 1.5 °C and 28.6 ± 1.7 °C in the third week—significantly (p < 0.05) higher in the test group. The new system also reduced total energy consumption by 58.3%. The usage rate of the thermal insulation area by piglets in the test and control groups was 47.5 ± 5.3% and 42.1 ± 6.6%. The daily weight gain of piglets in the test group was 9.8% higher than that of the control group, also significantly (p < 0.05) higher. This intelligent thermal insulation box enables precise and dynamic temperature control, reducing heating energy consumption and supporting improved piglet health and welfare. Full article
(This article belongs to the Section Pigs)
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<p>Design drawing of insulation box structure. (<b>a</b>) Design diagram. (<b>b</b>) Actual view.</p>
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<p>Structure diagram of intelligent insulation system for suckling piglets.</p>
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<p>Target temperature curve of insulation box.</p>
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<p>Temperature control logic flowchart.</p>
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<p>Performance testing sensor layout diagram. (<b>a</b>) Experimental group. (<b>b</b>) Control group, the red circle is the lampshade of the heat lamp.</p>
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<p>Distribution of farrowing rooms and their sensors. (<b>a</b>) Experimental pig house and indoor sensor distribution; (<b>b</b>) distribution of farrowing beds and sensors in the experimental group; (<b>c</b>) distribution of farrowing beds and sensors in the control group.</p>
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<p>Distribution of farrowing rooms and their sensors. (<b>a</b>) Experimental pig house and indoor sensor distribution; (<b>b</b>) distribution of farrowing beds and sensors in the experimental group; (<b>c</b>) distribution of farrowing beds and sensors in the control group.</p>
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<p>Average ambient temperature.</p>
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14 pages, 2080 KiB  
Article
A XGBoost-Based Prediction Method for Meat Sheep Transport Stress Using Wearable Photoelectric Sensors and Infrared Thermometry
by Ruiqin Ma, Runqing Chen, Buwen Liang and Xinxing Li
Sensors 2024, 24(23), 7826; https://doi.org/10.3390/s24237826 - 7 Dec 2024
Viewed by 468
Abstract
Transportation pressure poses a serious threat to the health of live sheep and the quality of their meat. So, the edible Hu sheep was chosen as the research object for meat sheep. We constructed a systematic biosignal detecting, processing, and modeling method. The [...] Read more.
Transportation pressure poses a serious threat to the health of live sheep and the quality of their meat. So, the edible Hu sheep was chosen as the research object for meat sheep. We constructed a systematic biosignal detecting, processing, and modeling method. The biosignal sensing was performed with wearable sensors (photoelectric sensor and infrared temperature measurement) for physiological dynamic sensing and continuous monitoring of the transport environment of meat sheep. Core waveform extraction and modern spectral estimation methods are used to determine and strip out the target signal waveform from it for the purpose of accurate sensing and the acquisition of key transport parameters. Subsequently, we built a qualitative stress assessment method based on external manifestations with reference to the Karolinska drowsiness scale to establish stage classification rules for monitoring data in the transportation environment of meat sheep. Finally, machine learning algorithms such as Gaussian Naive Bayes (GaussianNB), Passive-Aggressive Aggregative Classifier (PAC), Nearest Centroid (NC), K-Nearest Neighbor Classification (KNN), Random Forest (RF), Support Vector Classification (SVC), Gradient Boosting Decision Tree (GBDT), and eXtreme Gradient Boosting (XGB) were established to predict the classification models of transportation stress in meat sheep. Their classification results were compared. The results show that SVC and GBDT algorithms are more effective and the overall model classification accuracy reached 86.44% and 91.53%. XGB has the best results. The accuracy of the assessment of the transport stress state of meat sheep after the optimization of three parameters was 100%, 90.91%, and 93.33%, and the classification accuracy of the overall model reached 94.92%. The final results achieved improve transport reliability, reduce transport risk, and solve the problems of inefficient meat sheep transport supervision and quality control. Full article
(This article belongs to the Section Biosensors)
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<p>Flow chart of pulse wave sensing signal processing and transmission.</p>
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<p>Reconstruct the signal to obtain the PPG signal.</p>
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<p>Comparison figure of classification accuracy of different machine learning algorithms for optimization level.</p>
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13 pages, 3223 KiB  
Article
Effect of Maize (Zea mays) and Soybean (Glycine max) Cropping Systems on Weed Infestation and Resource Use Efficiency
by Aamir Ali, Shoaib Ahmed, Ghulam Mustafa Laghari, Abdul Hafeez Laghari, Aijaz Ahmed Soomro and Nida Jabeen
Agronomy 2024, 14(12), 2801; https://doi.org/10.3390/agronomy14122801 - 25 Nov 2024
Viewed by 425
Abstract
Agriculture has consistently improved to meet the needs of a growing global population; however, traditional monoculture farming, while highly productive, is facing challenges such as weed infestation and inefficient resource utilization. Herbicides effectively control weeds. However, their widespread use in weed management has [...] Read more.
Agriculture has consistently improved to meet the needs of a growing global population; however, traditional monoculture farming, while highly productive, is facing challenges such as weed infestation and inefficient resource utilization. Herbicides effectively control weeds. However, their widespread use in weed management has the potential to contaminate soil and water, endangering the ecosystem by damaging non-target plant and animal species. Therefore, the main objective of this study was to evaluate the impact of different maize and soybean cropping systems on weed infestation and resource utilization. The experiment was a randomized complete block design with three replications consisting of three cropping systems: sole maize (SM), sole soybean (SS), and maize–soybean strip intercropping (MSI). In this study, the main difference between SM, SS, and MSI was the planting density, which was 60,000 (SM), 100,000 (SS), and 160,000 (maize–soybean in MSI). We observed that a higher total leaf area index in MSI resulted in increased soil cover, which reduced the solar radiations for weeds and suppressed the weed growth by 17% and 11% as compared to SS and SM, respectively. Whereas the radiation use efficiency for companion crops in MSI was increased by 39% and 42% compared to SS and SM, respectively. Moreover, the increased soil cover by total leaf area index in MSI also increased the efficiency of water use. Furthermore, our results indicated that reduced weed-crop competition increased the resource use in MSI, which resulted in increased crop yield and land equivalent ratio (LER 1.6). Eventually, this resulted in reduced inputs and increased land productivity. Therefore, we suggest that MSI should be adopted in resource-limiting conditions with higher weed infestation as it can simultaneously promote ecological balance and improve agricultural output, thereby reducing the environmental effects of traditional cropping systems. Full article
(This article belongs to the Section Weed Science and Weed Management)
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<p>Monthly minimum (Min), maximum (Max), average (Avg.) temperature (Tem °C), relative humidity (RH, %) and precipitation (Pre, mm) at Tandojam during growing seasons of (<b>A</b>) 2021 and (<b>B</b>) 2022.</p>
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<p>The layout of the (<b>A</b>) maize–soybean strip intercropping system, (<b>B</b>) sole maize, and (<b>C</b>) sole soybean. The different arrows indicate the distance between two strips and plant to plant.</p>
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<p>Weed infestation (g/m<sup>2</sup>) as affected by the cropping systems during the growing seasons of (<b>A</b>) 2021 and (<b>B</b>) 2022. The SS, SM, and MSI represent the sole soybean, sole maize, and maize–soybean strip intercropping, respectively. The means are averaged over three replicates. Between the bars in groups, the different lowercase letters indicate a significant difference (<span class="html-italic">p</span> &lt; 0.05) between the treatments.</p>
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<p>The water use efficiency (g/mm) and radiation use efficiency (g MJ<sup>−1</sup>) were affected by the cropping systems during the growing seasons of 2021 and 2022. The SS, SM, and MSI represent the sole soybean, sole maize, and maize–soybean strip intercropping (<b>A</b>,<b>B</b>). The means are averaged over three replicates. The bars indicate ± standard errors (<span class="html-italic">n</span> = 3). Between the bars in the groups, the different lowercase letters indicate a significant difference (<span class="html-italic">p</span> &lt; 0.05) between the treatments.</p>
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<p>The grain yield (kg ha−<sup>1</sup>) of maize (<b>A</b>) and soybean (<b>B</b>) under the various cropping systems during the growing seasons of 2021 and 2022. The means are averaged over three replicates. The bars indicate ± standard errors (<span class="html-italic">n</span> = 3). Between the bars in the groups, the different lowercase letters indicate a significant difference (<span class="html-italic">p</span> &lt; 0.05) between the treatments.</p>
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<p>The partial LER of soybean and maize and LER of maize–soybean strip intercropping during the growing seasons of 2021 and 2022. The means are averaged over three replicates. The bars indicate ± standard errors (<span class="html-italic">n</span> = 3). Between the bars in the groups, the different lowercase letters indicate a significant difference (<span class="html-italic">p</span> &lt; 0.05) between the treatments.</p>
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<p>Illustration of light interception on different cropping systems. (<b>A</b>) maize–soyabean strip intercropping, (<b>B</b>) sole maize, and (<b>C</b>) Sole soybean.</p>
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17 pages, 4015 KiB  
Article
Evaluation of Performance and Longevity of Ti-Cu Dry Electrodes: Degradation Analysis Using Anodic Stripping Voltammetry
by Daniel Carvalho, Ana Margarida Rodrigues, João Santos, Dulce Geraldo, Armando Ferreira, Marcio Assolin Correa, Eduardo Alves, Nuno Pessoa Barradas, Claudia Lopes and Filipe Vaz
Sensors 2024, 24(23), 7477; https://doi.org/10.3390/s24237477 - 23 Nov 2024
Viewed by 479
Abstract
This study aimed to investigate the degradation of dry biopotential electrodes using the anodic stripping voltammetry (ASV) technique. The electrodes were based on Ti-Cu thin films deposited on different polymeric substrates (polyurethane, polylactic acid, and cellulose) by Direct Current (DC) magnetron sputtering. TiCu [...] Read more.
This study aimed to investigate the degradation of dry biopotential electrodes using the anodic stripping voltammetry (ASV) technique. The electrodes were based on Ti-Cu thin films deposited on different polymeric substrates (polyurethane, polylactic acid, and cellulose) by Direct Current (DC) magnetron sputtering. TiCu0.34 thin films (chemical composition of 25.4 at.% Cu and 74.6 at.% Ti) were prepared by sputtering a composite Ti target. For comparison purposes, a Cu-pure thin film was prepared under the same conditions and used as a reference. Both films exhibited dense microstructures with differences in surface topography and crystalline structure. The degradation process involved immersing TiCu0.34 and Cu-pure thin films in artificial sweat (prepared following the ISO standard 3160-2) for different durations (1 h, 4 h, 24 h, 168 h, and 240 h). ASV was the technique selected to quantify the amount of Cu(II) released by the electrodes immersed in the sweat solution. The optimal analysis conditions were set for 120 s and −1.0 V for time deposition and potential deposition, respectively, with a quantification limit of 0.050 ppm and a detection limit of 0.016 ppm. The results showed that TiCu0.34 electrodes on polyurethane substrates were significantly more reliable over time compared to Cu-pure electrodes. After 240 h of immersion, the TiCu0.34 electrodes released a maximum of 0.06 ppm Cu, while Cu-pure electrodes released 16 ppm. The results showed the significant impact of the substrate on the electrode’s longevity, with cellulose bases performing poorly. TiCu0.34 thin films on cellulose released 1.15 µg/cm2 of copper after 240 h, compared to 1.12 mg/cm2 from Cu-pure films deposited on the same substrate. Optical microscopy revealed that electrodes based on polylactic acid substrates were more prone to corrosion over time, whereas TiCu thin-film metallic glass-like structures on PU substrates showed extended lifespan. This study underscored the importance of assessing the degradation of dry biopotential electrodes for e-health applications, contributing to developing more durable and reliable sensing devices. While the study simulated real-world conditions using artificial sweat, it did not involve in vivo measurements. Full article
(This article belongs to the Special Issue Biomedical Electronics and Wearable Systems)
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<p>Electrochemical cell used for the ASV experiments.</p>
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<p>SEM images representative of (<b>a</b>) the surface morphology and (<b>b</b>) cross-section view of the film’s growth with the respective X-ray diffractograms for (<b>i</b>) Cu-pure film and (<b>ii</b>) TiCu<sub>0.34</sub> thin film.</p>
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<p>Variation in the peak current (Ip) of a 5.00 ppm solution of Cu(II) in artificial sweat as a function of (<b>a</b>) deposition time (t<sub>dep</sub>) at a deposition potential of −1.0 V and (<b>b</b>) deposition potential (E<sub>dep</sub>) with a deposition time of 120 s. Data were obtained using the ASV-SWV technique with the established parameters.</p>
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<p>Anodic stripping voltammograms of copper in artificial sweat obtained at the GCE electrode for the standard Cu(II) solutions with different concentrations. To ascertain the limit of quantification (LOQ) and the limit of detection (LOD) of the method, 6 replicate analyses of the standard Cu(II) solution with the lowest concentration (0.05 ppm) were performed. The relative standard deviation was less than 10%, satisfying the acceptance criterion, thus establishing the LOQ at 0.05 ppm. The LOD was estimated to be one-third of the LOQ, yielding a value of 0.016 ppm. Although this LOD is relatively low, it is higher than the values reported in the literature (0.0002 ppm) [<a href="#B22-sensors-24-07477" class="html-bibr">22</a>]. This suggests that while the current method is effective, there is still room for improvement.</p>
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<p>Copper concentration determined in artificial sweat released from the electrodes of (<b>i</b>) Cu-pure and (<b>ii</b>) TiCu<sub>0.34</sub>, immersed in artificial sweat using different substrates: (<b>a</b>) PU, (<b>b</b>) PLA, and (<b>c</b>) cellulose. The red line represents the LOD (limit of detection), and the green line represents the LOQ (limit of quantification).</p>
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<p>Copper concentration determined in artificial sweat released from the electrodes of (<b>i</b>) Cu-pure and (<b>ii</b>) TiCu<sub>0.34</sub>, immersed in artificial sweat using different substrates: (<b>a</b>) PU, (<b>b</b>) PLA, and (<b>c</b>) cellulose. The red line represents the LOD (limit of detection), and the green line represents the LOQ (limit of quantification).</p>
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<p>Mass of copper released per unit area in the artificial sweat solution from thin films of (<b>a<sub>i</sub></b>) Cu-pure and (<b>a<sub>ii</sub></b>) TiCu<sub>0.34</sub> deposited on the different substrates, along with the experimental voltammograms used to determine the cooper release for (<b>b<sub>i</sub></b>) Cu-pure electrodes and (<b>b<sub>ii</sub></b>) TiCu<sub>0.34</sub> pure electrodes.</p>
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<p>Mass of copper released per unit area in the artificial sweat solution from thin films of (<b>a<sub>i</sub></b>) Cu-pure and (<b>a<sub>ii</sub></b>) TiCu<sub>0.34</sub> deposited on the different substrates, along with the experimental voltammograms used to determine the cooper release for (<b>b<sub>i</sub></b>) Cu-pure electrodes and (<b>b<sub>ii</sub></b>) TiCu<sub>0.34</sub> pure electrodes.</p>
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<p>Optical characterisation of a (<b>i</b>) TiCu/PU, (<b>ii</b>) TiCu/PLA, (<b>iii</b>) TiCu/cellulose electrode’s surface before degradation: (<b>a</b>) are the images acquired by the Dino-Lite digital microscope and (<b>b</b>) the respective binary images, processed by MATLAB to calculate the optical defects (black areas in the image).</p>
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<p>Variation in the number of defects on the surface of the TiCu electrodes prepared by the functionalisation of different polymeric bases (<b>a</b>) PU, (<b>b</b>) PLA, and (<b>c</b>) cellulose for 1 h, 4 h, 24 h, 168 h, and 240 h of degradation.</p>
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29 pages, 7806 KiB  
Article
Formulation and Ex Vivo Evaluation of Ivermectin Within Different Nano-Drug Delivery Vehicles for Transdermal Drug Delivery
by Eunice Maureen Steenekamp, Wilna Liebenberg, Hendrik J. R. Lemmer and Minja Gerber
Pharmaceutics 2024, 16(11), 1466; https://doi.org/10.3390/pharmaceutics16111466 - 18 Nov 2024
Viewed by 1201
Abstract
Background/Objectives: Ivermectin gained widespread attention as the “miracle drug” during the coronavirus disease 2019 (COVID-19) pandemic. Its inclusion in the 21st World Health Organization (WHO) List of Essential Medicines is attributed to its targeted anti-helminthic response, high efficacy, cost-effectiveness and favorable safety profile. [...] Read more.
Background/Objectives: Ivermectin gained widespread attention as the “miracle drug” during the coronavirus disease 2019 (COVID-19) pandemic. Its inclusion in the 21st World Health Organization (WHO) List of Essential Medicines is attributed to its targeted anti-helminthic response, high efficacy, cost-effectiveness and favorable safety profile. Since the late 2000s, this bio-inspired active pharmaceutical ingredient (API) gained renewed interest for its diverse therapeutic capabilities. However, producing ivermectin formulations does remain challenging due to its poor water solubility, resulting in low bioavailability after oral administration. Therefore, the transdermal drug delivery of ivermectin was considered to overcome these challenges, which are observed after oral administration. Methods: Ivermectin was incorporated in a nano-emulsion, nano-emulgel and a colloidal suspension as ivermectin-loaded nanoparticles. The nano-drug delivery vehicles were optimized, characterized and evaluated through in vitro membrane release studies, ex vivo skin diffusion studies and tape-stripping to determine whether ivermectin was successfully released from its vehicle and delivered transdermally and/or topically throughout the skin. This study concluded with cytotoxicity tests using the methyl thiazolyl tetrazolium (MTT) and neutral red (NR) assays on both human immortalized epidermal keratinocytes (HaCaT) and human immortalized dermal fibroblasts (BJ-5ta). Results: Ivermectin was successfully released from each vehicle, delivered transdermally and topically throughout the skin and demonstrated little to no cytotoxicity at concentrations that diffused through the skin. Conclusions: The type of nano-drug delivery vehicle used to incorporate ivermectin influences its delivery both topically and transdermally, highlighting the dynamic equilibrium between the vehicle, the API and the skin. Full article
(This article belongs to the Special Issue Transdermal Delivery: Challenges and Opportunities)
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<p>SEM micrographs of <b>NPs</b>.</p>
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<p>XRPD overlay for: (<b>a</b>) ivermectin, (<b>b</b>) ivermectin-loaded <b>NPs</b>, (<b>c</b>) PCL, (<b>d</b>) PVA and (<b>e</b>) sucrose.</p>
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<p>(<b>a</b>) Average cumulative amount of ivermectin released per area (μg/cm<sup>2</sup>) over 6 h during the in vitro membrane release studies from all the nano-drug delivery vehicles, and (<b>b</b>) boxplot displaying the average (dashed lines) and median (solid lines) flux (μg/cm<sup>2</sup>.h) of ivermectin for the nano-drug delivery vehicles during the in vitro membrane release studies over a period of 6 h.</p>
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<p>(<b>a</b>) Average cumulative amount of ivermectin diffused per area (μg/cm<sup>2</sup>) over 12 h during the ex vivo skin diffusion studies from all the nano-drug delivery vehicles, and (<b>b</b>) boxplot displaying the average (dashed lines) and median (solid lines) flux (μg/cm<sup>2</sup>.h) of ivermectin for the nano-drug delivery vehicles during the ex vivo skin diffusion studies over a period of 12 h.</p>
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<p>Boxplot displaying the average (dashed lines) and median (solid lines) concentration (μg/mL) of ivermectin from the different nano-drug delivery vehicles (<b>NE</b> and <b>NEG</b>) that were delivered in the SCE and ED after each 12 h ex vivo skin diffusion study.</p>
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<p>%Cell viability of the HaCaT cells after treatment with different concentrations of (<b>a</b>) API, <b>NE</b> and <b>PNE</b>, and (<b>b</b>) <b>CS</b> using the MTT assay, while the NR assay was used for (<b>c</b>) API, <b>NE</b> and <b>PNE</b>, and (<b>d</b>) <b>CS</b>.</p>
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<p>%Cell viability of the BJ-5sta cells after treatment with different concentrations of (<b>a</b>) API, <b>NE</b> and <b>PNE</b>, and (<b>b</b>) <b>CS</b> using the MTT assay, while the NR assay was used for (<b>c</b>) API, <b>NE</b> and <b>PNE</b>, and (<b>d</b>) <b>CS</b>.</p>
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14 pages, 4899 KiB  
Article
CRISPR-Cas13a-Based Lateral Flow Assay for Detection of Bovine Leukemia Virus
by Yuxi Zhao, Jingwen Dai, Zhen Zhang, Jianguo Chen, Yingyu Chen, Changmin Hu, Xi Chen and Aizhen Guo
Animals 2024, 14(22), 3262; https://doi.org/10.3390/ani14223262 - 13 Nov 2024
Viewed by 569
Abstract
Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL), which presents worldwide prevalence. BLV caused substantial economic loss in China around the 1980s; then, it could not be detected for some time, until recently. Due to its latent and [...] Read more.
Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL), which presents worldwide prevalence. BLV caused substantial economic loss in China around the 1980s; then, it could not be detected for some time, until recently. Due to its latent and chronic characteristics, the efficient and accurate detection of BLV is of utmost significance to the timely implementation of control measures. Therefore, this study harnessed the recombinase-aided amplification (RAA), clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 13a (Cas13a) technology, and lateral flow (LF) strips to develop an efficient method for detection of BLV. In this method, isothermal amplification of the targeted pol gene is performed at 37 °C with a detection threshold of 1 copy/µL, and the procedure is completed in 100 min. This assay demonstrated high selectivity for BLV, as indicated by the absence of a cross-reaction with six common bovine pathogens. Remarkably, 100 blood samples from dairy cows were tested in parallel with a conventional quantitative polymerase chain reaction (qPCR) and this method and the results showed 100% agreement. Furthermore, this method exhibited good repeatability. In conclusion, in this study, we established a sensitive and specific method for BLV detection, which shows promise for application in BLV surveillance. Full article
(This article belongs to the Section Cattle)
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<p>Schematic representation of the CRISPR-Cas13a-LF BLV test workflow. The BLV genome was extracted from bovine blood samples, amplified by RAA, and transcribed into RNA to activate the Cas13a nuclease. The activated nuclease then recognized crRNA and cleaved the reporter molecule, resulting in a visible band on the test strip. The presence of either the test line alone or both the test and control lines indicates a positive result, whereas the presence of only the control line indicates a negative result. RAA = recombinase-aided amplification.</p>
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<p>The amplification curves obtained by using the <span class="html-italic">pol</span>1 primer. The blue curve represents the negative control, while the green and red curves represent two replicates. The red horizontal line represents the threshold line. The x-axis represents the number of fluorescence collections, and the y-axis represents the fluorescence values. RFU: Relative Fluorescence Units.</p>
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<p>The amplification curves obtained by using the <span class="html-italic">env</span> primer. The green curve represents the negative control, while the red and black curves represent two replicates. The red horizontal line represents the threshold line. The x-axis represents the number of fluorescence collections, and the y-axis represents the fluorescence values. RFU: Relative Fluorescence Units.</p>
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<p>The amplification curves obtained by using the <span class="html-italic">pol</span>2 primer. The pink curve represents the negative control, while the green and purple curves represent two replicates. The red horizontal line represents the threshold line. The x-axis represents the number of fluorescence collections, and the y-axis represents the fluorescence values. RFU: Relative Fluorescence Units.</p>
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<p>CRISPR-Cas13a-LF detection for validation of crRNAs. PTC (<span class="html-italic">env</span>), pUC57 <span class="html-italic">env</span> plasmid; PTC (<span class="html-italic">pol</span>2), pUC57 <span class="html-italic">pol</span>2 plasmid; NTC, negative control.</p>
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<p>Sensitivity detection of <span class="html-italic">env</span> primer combined with crRNA2. Plasmid diluted with a 10-fold gradient: 1 × 10<sup>8</sup> copies/μL–1 × 1 copy/μL; NTC represents the negative control; Control represents the control line; Test represents the test line.</p>
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<p>Sensitivity detection of <span class="html-italic">pol</span>2 primer combined with crRNA3. Plasmid diluted with a 10-fold gradient: 1 × 10<sup>8</sup> copies/μL–1 copy/μL. NTC represents the negative control; Control represents the control line; Test represents the test line.</p>
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<p>Specificity test of CRISPR-Cas13a-LF. pUC57-pol2 refers to <span class="html-italic">pol</span>2 plasmid. BLV<sup>+</sup> indicates BLV-positive samples. The six common bovine pathogens considered were bovine viral diarrhea virus (BVDV), bovine coronavirus (BCoV), <span class="html-italic">Escherichia coli (E. coli)</span>, lumpy skin disease virus (LSDV), <span class="html-italic">Salmonella</span>, and <span class="html-italic">Cryptosporidium</span>. NTC represents the negative control. Control represents the control line. Test represents the test line.</p>
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<p>Clinical sample test with CRISPR-Cas13a-LF method. (<b>A-1</b>,<b>A-2</b>) First round of testing; (<b>B-1</b>,<b>B-2</b>) second round of testing. PTC represents positive control; NTC represents negative control.</p>
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<p>Clinical sample test with CRISPR-Cas13a-LF method. (<b>A-1</b>,<b>A-2</b>) First round of testing; (<b>B-1</b>,<b>B-2</b>) second round of testing. PTC represents positive control; NTC represents negative control.</p>
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19 pages, 1115 KiB  
Review
Understanding the Food and Nutrition Insecurity Drivers in Some Emergency-Affected Countries in the Eastern Mediterranean Region from 2020 to 2024
by Salwa Jamal Al Sharjabi, Ayoub Al Jawaldeh, Ola El Hajj Hassan and Fekri Dureab
Nutrients 2024, 16(22), 3853; https://doi.org/10.3390/nu16223853 - 11 Nov 2024
Viewed by 1757
Abstract
This research seeks to enhance the understanding of the multifaceted drivers of food and nutrition insecurity in emergency-affected countries within the Eastern Mediterranean region and investigate the dynamics of food and nutrition security in countries facing emerging emergencies. This is a descriptive aim [...] Read more.
This research seeks to enhance the understanding of the multifaceted drivers of food and nutrition insecurity in emergency-affected countries within the Eastern Mediterranean region and investigate the dynamics of food and nutrition security in countries facing emerging emergencies. This is a descriptive aim to determine the key factors and challenges affecting food security and nutrition status in ten countries in the Eastern Mediterranean region (Afghanistan, Djibouti, Iraq, Lebanon, Pakistan, Palestine (Gaza Strip), Somalia, Sudan, Syria, and Yemen). The research reveals that all selected countries experienced severe levels of food insecurity, with many reaching Phase 3 or above according to the IPC classification. In 2020, Afghanistan and Yemen were particularly hard-hit, with food insecurity affecting 42% and 45% of their populations; in 2024 in Gaza and Sudan, the same figures were 93% and 54% of the population, respectively, representing worse food insecurity crises in the region. Somalia, Sudan, and Djibouti also faced significant food insecurity rates. Many key drivers of food security are standard in most countries, and the linkage between food insecurity and malnutrition levels has a similar trend in almost all countries. However, none of the countries achieved all the 2025 global nutrition targets, while some reached one or two targets. Reaching sustainable development goals is still challenging in these countries since nutrition and food security levels, included in many goals, have not yet been reached. Food security and malnutrition in emergency-affected countries are driven by conflict, political instability, natural disasters, and socioeconomic conditions, which disrupt agricultural activities and infrastructure, exacerbating these challenges. To address these issues, we recommend a multisectoral approach, conflict resolution, climate-smart agriculture, integration of emergency responses with long-term strategies, and strengthening health and nutrition information systems. Full article
(This article belongs to the Section Nutrition and Public Health)
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<p>Map of the Eastern mediterranean countries [<a href="#B8-nutrients-16-03853" class="html-bibr">8</a>].</p>
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<p>UNICEF malnutrition conceptual framework.</p>
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18 pages, 7214 KiB  
Article
Spatially Explicit Life Cycle Global Warming and Eutrophication Potentials of Confined Dairy Production in the Contiguous US
by Xiaobo Xue Romeiko, Wangjian Zhang, Xuesong Zhang and Jun-Ki Choi
Environments 2024, 11(11), 230; https://doi.org/10.3390/environments11110230 - 22 Oct 2024
Viewed by 606
Abstract
Assessing the spatially explicit life cycle environmental impacts of livestock production systems is critical for understanding the spatial heterogeneity of environmental releases and devising spatially targeted remediation strategies. This study presents the first spatially explicit assessment on life cycle global warming and eutrophication [...] Read more.
Assessing the spatially explicit life cycle environmental impacts of livestock production systems is critical for understanding the spatial heterogeneity of environmental releases and devising spatially targeted remediation strategies. This study presents the first spatially explicit assessment on life cycle global warming and eutrophication potentials of confined dairy production at a county scale in the contiguous US. The Environmental Policy Integrated Climate model was used to estimate greenhouse gases (GHGs), NH3, and aqueous nutrient releases of feed production. The Greenhouse gases, Regulated Emissions, and Energy use in Transportation model and Commodity Flow Survey were used to assess GHGs and NH3 from feed transportation. Emission-factor-based approaches were primarily used to calculate GHGs from enteric fermentation, and GHGs, NH3, and aqueous nutrient releases from manure management. Characterization factors reported by the Intergovernmental Panel on Climate Change and Tool for Reduction and Assessment of Chemicals and other Environmental Impacts model were used to compute global warming and eutrophication potentials, respectively. The analyses revealed that life cycle global warming and eutrophication potentials of confined dairy production presented significant spatial heterogeneity among the US counties. For example, the life cycle global warming potential ranged from 462 kg CO2-eq/head to 14,189 kg CO2-eq/head. Surprisingly, sourcing feed locally cannot effectively reduce life cycle global warming and eutrophication potentials of confined dairy production. The feed supply scenarios with the lowest life cycle environmental impacts depend on the life cycle environmental impacts of feed production, geographic locations of confined dairy production, and specific impact categories. In addition, installing buffer strips in feed-producing hotspots can effectively reduce life cycle nutrient releases of confined dairy production. If 200 counties with the highest life cycle EP of corn adopt buffer strips, the reduction in life cycle EP of confined dairy production could reach 24.4%. Full article
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<p>System boundary for life cycle assessment of confined dairy production.</p>
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<p>Four feed sourcing scenarios including local, nearby, regional and national sourcing. The colored networks in the middle map represents the national sourcing scenairos for dairy operations in Erath county of Texas, Hamilton county of Kansas, Manitowoc county of Wisconsin, Tulare county of California, Wayne county of Nebraska.</p>
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<p>Life cycle global warming potential (GWP) of confined dairy production per head and per county in the contiguous United States.</p>
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<p>Life Cycle Eutrophication Potential (EP) of Confined Dairy Production in the Contiguous United States.</p>
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<p>The contributions of various stages to the total life cycle global warming potential (GWP) and eutrophication potential (EP) of confined dairy production.</p>
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<p>Life cycle global warming potential (GWP) and eutrophication potential (EP) of feed supply for top confined dairy-producing counties under local, nearby, regional and national sourcing scenarios. These counties include Antelope in Nebraska, Deaf Smith in Texas, Grant in Wisconsin, Roosevelt in New Mexico, and Sioux in Iowa.</p>
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<p>Reduction percentages in life cycle EP of confined dairy production impacts due to installing buffer strips in feed-producing counties.</p>
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<p>Sensitivity analyses of life cycle GWP and EP/head for confined dairy production.</p>
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22 pages, 5749 KiB  
Article
DCW-YOLO: An Improved Method for Surface Damage Detection of Wind Turbine Blades
by Li Zou, Anqi Chen, Chunzi Li, Xinhua Yang and Yibo Sun
Appl. Sci. 2024, 14(19), 8763; https://doi.org/10.3390/app14198763 - 28 Sep 2024
Viewed by 1194
Abstract
Wind turbine blades (WTBs) are prone to damage from their working environment, including surface peeling and cracks. Early and effective detection of surface defects on WTBs can avoid complex and costly repairs and serious safety hazards. Traditional object detection methods have disadvantages of [...] Read more.
Wind turbine blades (WTBs) are prone to damage from their working environment, including surface peeling and cracks. Early and effective detection of surface defects on WTBs can avoid complex and costly repairs and serious safety hazards. Traditional object detection methods have disadvantages of insufficient detection capabilities, extended model inference times, low recognition accuracy for small objects, and elongated strip defects within WTB datasets. In light of these challenges, a novel model named DCW-YOLO for surface damage detection of WTBs is proposed in this research, which leverages image data collected by unmanned aerial vehicles (UAVs) and the YOLOv8 algorithm for image analysis. Firstly, Dynamic Separable Convolution (DSConv) is introduced into the C2f module of YOLOv8, allowing the model to more effectively focus on the geometric structural details associated with damage on WTBs. Secondly, the upsampling method is replaced with the content-aware reassembly of features (CARAFE), which significantly minimizes the degradation of image characteristics throughout the upsampling process and boosts the network’s ability to extract features. Finally, the loss function is substituted with the WIoU (Wise-IoU) strategy. This strategy allows for a more accurate regression of the target bounding boxes and helps to improve the reliability in the localization of WTBs damages, especially for low-quality examples. This model demonstrates a notable superiority in surface damage detection of WTBs compared to the original YOLOv8n and has achieved a substantial improvement in the [email protected] metric, rising from 91.4% to 93.8%. Furthermore, in the more rigorous [email protected]–0.95 metric, it has also seen an increase from 68.9% to 71.2%. Full article
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<p>The structure of YOLOv8 model.</p>
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<p>The structure of DSConv.</p>
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<p>Iteration of DSConv: (<b>a</b>) Schematic of the coordinates calculation of the DSConv. (<b>b</b>) The receptive field of DSConv.</p>
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<p>The overall architecture of CARAFE.</p>
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<p>The structure of DCW-YOLO model.</p>
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<p>Dataset samples of WTBs: (<b>a</b>,<b>b</b>) are peeling samples. (<b>c</b>,<b>d</b>) are crack samples.</p>
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<p>mAP of the model: (<b>a</b>) the mAP of the original YOLOv8; (<b>b</b>) the mAP of the DCW-YOLO.</p>
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<p>Detection performance of the model: (<b>a</b>) the detection performance of YOLOv8; (<b>b</b>) the detection performance of DCW-YOLO.</p>
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<p>mAP values for different models.</p>
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<p>WTB damage detection results: (<b>a</b>) YOLOv5 detection effect. (<b>b</b>) YOLOv6 detection effect. (<b>c</b>) YOLOv7-Tiny detection effect. (<b>d</b>) YOLOv8 detection effect. (<b>e</b>) YOLOv10 detection effect. (<b>f</b>) DCW-YOLO detection effect.</p>
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24 pages, 10209 KiB  
Article
An Attitude Determination and Sliding Mode Control Method for Agile Whiskbroom Scanning Maneuvers of Microsatellites
by Xinyan Yang, Zhaoming Li, Lei Li and Yurong Liao
Aerospace 2024, 11(9), 778; https://doi.org/10.3390/aerospace11090778 - 20 Sep 2024
Viewed by 565
Abstract
Microsatellites have significantly impacted space missions by offering advanced technology at a low cost. This study introduces an attitude determination and control algorithm for agile whiskbroom scanning maneuvers in microsatellites to enable wide-swath target detection for low-Earth-orbit microsatellites. First, an angular velocity calculation [...] Read more.
Microsatellites have significantly impacted space missions by offering advanced technology at a low cost. This study introduces an attitude determination and control algorithm for agile whiskbroom scanning maneuvers in microsatellites to enable wide-swath target detection for low-Earth-orbit microsatellites. First, an angular velocity calculation model for agile whiskbroom scanning is established. A methodology has been developed to calculate the maximum available time for whiskbroom scanning from one side of the sub-satellite point to the other while ensuring the seamless joining of adjacent strips to avoid missing targets. Thereafter, a gyro- and magnetometer-based cubature Kalman filter is put forward for microsatellite attitude estimation. Furthermore, for attitude control, a hybrid manipulation law capable of preventing singularities and escaping singularity surfaces is designed to ensure high-precision torque output from the control moment gyroscopes (CMGs) used as actuators. The benefits of the linear sliding mode and fast terminal sliding mode are integrated, and a non-singular sliding surface is designed, yielding a non-singular fast terminal sliding mode attitude control algorithm for tracking the desired trajectory. This algorithm effectively suppresses chattering and enhances dynamic performance without using a switching term. A semi-physical simulation experiment system is also conducted on the ground to validate the proposed algorithm’s high-precision tracking of the planned whiskbroom scanning path. The experimental results demonstrate an attitude angle control accuracy of 4 × 10−2 degrees and angular velocity control accuracy of 0.01°/s and thus the effectiveness of the proposed algorithm. Full article
(This article belongs to the Section Aeronautics)
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<p>Schematic of agile whiskbroom scanning maneuvers of microsatellites.</p>
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<p>Overlap increase for image stitching.</p>
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<p>Geometric relationship of satellite imaging regions.</p>
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<p>Correspondence of satellite travel distance and frame swath in one whiskbroom scanning cycle.</p>
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<p>Pyramid configuration of the four-SGCMG system.</p>
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<p>Space magnetic field simulator.</p>
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<p>Internal structure of the microsatellite electrical model.</p>
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<p>Magnetometer.</p>
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<p>Gyroscope.</p>
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<p>Desired Euler angles.</p>
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<p>Desired angular velocity.</p>
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<p>Attitude tracking error of NFTSMC in Euler angle.</p>
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<p>Angular velocity tracking error of NFTSMC.</p>
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<p>Control torques of NFTSMC.</p>
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<p>Singularity measure.</p>
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<p>Angular momentum of CMGs.</p>
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<p>Angles of CMGs rotation.</p>
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14 pages, 1585 KiB  
Article
TAFENet: A Two-Stage Attention-Based Feature-Enhancement Network for Strip Steel Surface Defect Detection
by Li Zhang, Zhipeng Fu, Huaping Guo, Yan Feng, Yange Sun and Zuofei Wang
Electronics 2024, 13(18), 3721; https://doi.org/10.3390/electronics13183721 - 19 Sep 2024
Viewed by 592
Abstract
Strip steel serves as a crucial raw material in numerous industries, including aircraft and automobile manufacturing. Surface defects in strip steel can degrade the performance, quality, and appearance of industrial steel products. Detecting surface defects in steel strip products is challenging due to [...] Read more.
Strip steel serves as a crucial raw material in numerous industries, including aircraft and automobile manufacturing. Surface defects in strip steel can degrade the performance, quality, and appearance of industrial steel products. Detecting surface defects in steel strip products is challenging due to the low contrast between defects and background, small defect targets, as well as significant variations in defect sizes. To address these challenges, a two-stage attention-based feature-enhancement network (TAFENet) is proposed, wherein the first-stage feature-enhancement procedure utilizes an attentional convolutional fusion module with convolution to combine all four-level features and then strengthens the features of different levels via a residual spatial-channel attention connection module (RSC). The second-stage feature-enhancement procedure combines three-level features using an attentional self-attention fusion module and then strengthens the features using a RSC attention module. Experiments on the NEU-DET and GC10-DET datasets demonstrated that the proposed method significantly improved detection accuracy, thereby confirming the effectiveness and generalization capability of the proposed method. Full article
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<p>Architecture of the proposed TAFENet with three main parts: feature extraction backbone, feature-enhancement neck, and detection heads. The feature fusion neck network has two feature-enhancement stages. First, the four-level features output by the backbone network are input into the neck network, then all of them are input into the FSFE (first-stage feature enhancement), where the outputs are fused with the features of the second and third layers through the RSC module. Subsequently, the features of the second, third, and fourth layers are input into the SSFE (second-stage feature enhancement), and the outputs are fused with the features of the third and fourth layers through the RSC module.</p>
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<p>Structure of a self-attention block. The input activation map size is <math display="inline"><semantics> <mrow> <mi mathvariant="italic">C</mi> <mo>×</mo> <mi mathvariant="italic">H</mi> <mo>×</mo> <mi mathvariant="italic">W</mi> </mrow> </semantics></math>. <span class="html-italic">N</span> is the number of heads.</p>
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<p>Structure of SAB. <math display="inline"><semantics> <msub> <mi>x</mi> <mi>g</mi> </msub> </semantics></math> donates global feature information from the AC or AS module, and <math display="inline"><semantics> <msub> <mi>x</mi> <mi>l</mi> </msub> </semantics></math> donates local feature information from the backbone network.</p>
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<p>Structure of the CAB. The CAB calculates the attention coefficient through global average pooling and global maximum pooling branches, respectively. The multilayer perceptrons in the two branches share parameters.</p>
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<p>Six types of defects in the NEU-DET dataset. (<b>a</b>) Crazing, (<b>b</b>) inclusion, (<b>c</b>) patches, (<b>d</b>) pitted surface, (<b>e</b>) rolled-in scale, and (<b>f</b>) scratches.</p>
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<p>Ten types of defects in the GC10-DET dataset. (<b>a</b>) Punching (Pu), (<b>b</b>) weld line (Wl), (<b>c</b>) crescent gap (Cg), (<b>d</b>) water spot (Ws), (<b>e</b>) oil spot (Os), (<b>f</b>) silk spot (Ss), (<b>g</b>) inclusion (In), (<b>h</b>) rolled pit (Rp), (<b>i</b>) crease (Cr), and (<b>j</b>) waist folding (Wf).</p>
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<p>Visualized detection results on the NEU-DET dataset. The detection category and confidence are shown above the detection box.</p>
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