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BACKGROUND: A cost-effective Escherichia coli expression system has gained popularity for producing virus-like particle (VLP) vaccines. However, the challenge lies in balancing the endotoxin residue and removal costs, as residual endotoxins can cause inflammatory reactions in the body. RESULTS: In this study, porcine parvovirus virus-like particles (PPV-VLPs) were successfully assembled from Decreased Endotoxic BL21 (BL21-DeE), and the effect of structural changes in the lipid A of BL21 on endotoxin activity, immunogenicity, and safety was investigated. The lipopolysaccharide purified from BL21-DeE produced lower IL-6 and TNF-α than that from wild-type BL21 (BL21-W) in both RAW264.7 cells and BALB/c mice. Additionally, mice immunized with PPV-VLP derived form BL21-DeE (BL21-DeE-VLP) showed significantly lower production of inflammatory factors and a smaller increase in body temperature within 3 h than those immunized with VLP from BL21-W (BL21-W-VLP) and endotoxin-removed VLP (ReE-VLP). Moreover, mice in the BL21-DeE-VLP immunized group had similar levels of serum antibodies as those in the BL21-W-VLP group but significantly higher levels than those in the ReE-VLP group. Furthermore, the liver, lungs, and kidneys showed no pathological damage compared with the BL21-W-VLP group. CONCLUSION: Overall, this study proposes a method for producing VLP with high immunogenicity and minimal endotoxin activity without chemical or physical endotoxin removal methods. This method could address the issue of endotoxin residues in the VLP and provide production benefits.
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Endotoxinas , Escherichia coli , Lípido A , Ratones Endogámicos BALB C , Parvovirus Porcino , Vacunas de Partículas Similares a Virus , Animales , Ratones , Escherichia coli/genética , Escherichia coli/metabolismo , Parvovirus Porcino/inmunología , Parvovirus Porcino/genética , Vacunas de Partículas Similares a Virus/inmunología , Endotoxinas/inmunología , Células RAW 264.7 , Lípido A/inmunología , Lípido A/análogos & derivados , Interleucina-6/inmunología , Factor de Necrosis Tumoral alfa/metabolismo , Femenino , Porcinos , Lipopolisacáridos/inmunologíaRESUMEN
BACKGROUND: Helicobacter pylori (H. pylori) colonizes the human gastric mucosa and is implicated in the development of gastric cancer (GC). The tumor microenvironment is characterized by hypoxia, where hypoxia-inducible factor-1α (HIF-1α) plays a key role as a transcription factor, but the mechanisms underlying H. pylori-induced HIF-1α expression and carcinogenesis remain unclear. AIM: To explore the underlying mechanism of H. pylori-induced HIF-1α expression in promoting the malignant biological behavior of gastric epithelial cells (GES-1). METHODS: The study was conducted with human GES-1 cells in vitro. Relative protein levels of methyltransferase-like protein 14 (METTL14), HIF-1α, main proteins of the PI3K/AKT pathway, epithelial-mesenchymal transition (EMT) biomarkers, and invasion indicators were detected by Western blot. Relative mRNA levels of METTL14 and HIF-1α were detected by quantitative reverse transcription-polymerase chain reaction. mRNA stability was evaluated using actinomycin D, and the interaction between METTL14 and HIF-1α was confirmed by immunofluorescence staining. Cell proliferation and migration were evaluated by cell counting kit-8 assay and wound healing assay, respectively. RESULTS: H. pylori promoted HIF-1α expression and activated the PI3K/AKT pathway. Notably, METTL14 was downregulated in H. pylori-infected gastric mucosal epithelial cells and positively regulated HIF-1α expression. Functional experiments showed that the overexpression of HIF-1α or knockdown of METTL14 enhanced the activity of the PI3K/AKT pathway, thereby driving a series of malignant transformation, such as EMT and cell proliferation, migration, and invasion. By contrast, the knockdown of HIF-1α or overexpression of METTL14 had an opposite effect. CONCLUSION: H. pylori-induced underexpression of METTL14 promotes the translation of HIF-1α and accelerates tumor progression by activating the PI3K/AKT pathway. These results provide novel insights into the carcinogenesis of GC.
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The membrane-associated RING-CH (MARCH) family of proteins are members of the E3 ubiquitin ligase family and are essential for a variety of biological functions. Currently, MARCH proteins are discovered to execute antiviral functions by directly triggering viral protein degradation or blocking the furin cleavage of viral class I fusion proteins. Here, we report a novel antiviral mechanism of MARCH1 and MARCH2 (MARCH1/2) in the replication of Pseudorabies virus (PRV), a member of the Herpesviridae family. We discovered MARCH1/2 restrict PRV replication at the cell-to-cell fusion step. Furthermore, MARCH1/2 block gB cleavage, and this is dependent on their E3 ligase activity. Interestingly, the blocking of gB cleavage by MARCH1/2 does not contribute to their antiviral activity in vitro. We discovered that MARCH1/2 are associated with the cell-to-cell fusion complex of gB, gD, gH, and gL and trap these viral proteins in the trans-Golgi network (TGN) rather than degrading them. Overall, we conclude that MARCH1/2 inhibit PRV by trapping the viral cell-to-cell fusion complex in TGN.
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Herpesvirus Suido 1 , Ubiquitina-Proteína Ligasas , Replicación Viral , Red trans-Golgi , Herpesvirus Suido 1/fisiología , Animales , Red trans-Golgi/virología , Red trans-Golgi/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Fusión Celular , Porcinos , Línea Celular , Humanos , Proteínas Virales/metabolismo , Proteínas Virales/genética , Células HEK293 , Seudorrabia/virologíaRESUMEN
Recombination is a pervasive phenomenon in RNA viruses and an important strategy for accelerating the evolution of RNA virus populations. Recombination in the porcine reproductive and respiratory syndrome virus (PRRSV) was first reported in 1999, and many case reports have been published in recent years. In this review, all the existing reports on PRRSV recombination events were collected, and the genotypes, parental strains, and locations of the recombination breakpoints have been summarized and analyzed. The results showed that the recombination pattern constantly changes; whether inter- or intra-lineage recombination, the recombination hotspots vary in different recombination patterns. The virulence of recombinant PRRSVs was higher than that of the parental strains, and the emergence of virulence reversion was caused by recombination after using MLV vaccines. This could be attributed to the enhanced adaptability of recombinant PRRSV for entry and replication, facilitating their rapid propagation. The aim of this paper was to identify common features of recombinant PRRSV strains, reduce the recombination risk, and provide a foundation for future research into the mechanism of PRRSV recombination.
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Síndrome Respiratorio y de la Reproducción Porcina , Virus del Síndrome Respiratorio y Reproductivo Porcino , Recombinación Genética , Virus del Síndrome Respiratorio y Reproductivo Porcino/genética , Virus del Síndrome Respiratorio y Reproductivo Porcino/clasificación , Virus del Síndrome Respiratorio y Reproductivo Porcino/patogenicidad , Animales , Porcinos , Síndrome Respiratorio y de la Reproducción Porcina/virología , Genotipo , Virulencia , Genoma Viral , Replicación Viral , FilogeniaRESUMEN
The membrane-associated RING-CH 8 protein (MARCH8), a member of the E3 ubiquitin ligase family, has broad-spectrum antiviral activity. However, some viruses hijack MARCH8 to promote virus replication, highlighting its dual role in the viral lifecycle. Most studies on MARCH8 have focused on RNA viruses, leaving its role in DNA viruses largely unexplored. Pseudorabies virus (PRV) is a large DNA virus that poses a potential threat to humans. In this study, we found that MARCH8 inhibited PRV replication at the cell-to-cell fusion stage. Interestingly, our findings proved that MARCH8 blocks gB cleavage by recruiting furin but this activity does not inhibit viral infection in vitro. Furthermore, we confirmed that MARCH8 inhibits cell-to-cell fusion independent of its E3 ubiquitin ligase activity but dependent on the interaction with the cell-to-cell fusion complex (gB, gD, gH, and gL). Finally, we discovered that the distribution of the cell-to-cell fusion complex is significantly altered and trapped within the trans-Golgi network. Overall, our results indicate that human MARCH8 acts as a potent antiviral host factor against PRV via trapping the cell-to-cell fusion complex in the trans-Golgi network.
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Fusión Celular , Herpesvirus Suido 1 , Ubiquitina-Proteína Ligasas , Replicación Viral , Red trans-Golgi , Animales , Humanos , Línea Celular , Herpesvirus Suido 1/fisiología , Red trans-Golgi/metabolismo , Red trans-Golgi/virología , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
Stretching elastic materials containing nanoparticle lattices is common in research and industrial settings, yet our knowledge of the deformation process remains limited. Understanding how such lattices reconfigure is critically important, as changes in microstructure lead to significant alterations in their performance. This understanding has been extremely difficult to achieve due to a lack of fundamental rules governing the rearrangements. Our study elucidates the physical processes and underlying mechanisms of three-dimensional lattice transformations in a polymeric photonic crystal from 0% to over 200% strain during uniaxial stretching. Corroborated by comprehensive experimental characterizations, we present analytical models that precisely predict both the three-dimensional lattice structures and the macroscale deformations throughout the stretching process. These models reveal how the nanoparticle lattice and matrix polymer jointly determine the resultant structures, which breaks the original structural symmetry and profoundly changes the dispersion of photonic bandgaps. Stretching induces shifting of the main pseudogap structure out from the 1st Brillouin zone and the merging of different symmetry points. Evolutions of multiple photonic bandgaps reveal potential optical singularities shifting with strain. This work sets a new benchmark for the reconfiguration of soft material structures and may lay the groundwork for the study of stretchable three-dimensional topological photonic crystals.
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In China, porcine reproductive and respiratory syndrome virus (PRRSV) vaccines are widely used. These vaccines, which contain inactivated and live attenuated vaccines (LAVs), are produced by MARC-145 cells derived from the monkey kidney cell line. However, some PRRSV strains in MARC-145 cells have a low yield. Here, we used two type 2 PRRSV strains (CH-1R and HuN4) to identify the genes responsible for virus yield in MARC-145 cells. Our findings indicate that the two viruses have different spread patterns, which ultimately determine their yield. By replacing the viral envelope genes with a reverse genetics system, we discovered that the minor envelope proteins, from GP2a to GP4, play a crucial role in determining the spread pattern and yield of type 2 PRRSV in MARC-145 cells. The cell-free transmission pattern of type 2 PRRSV appears to be more efficient than the cell-to-cell transmission pattern. Overall, these findings suggest that GP2a to GP4 contributes to the spread pattern and yield of type 2 PRRSV.
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Guanidinas , Piperazinas , Síndrome Respiratorio y de la Reproducción Porcina , Virus del Síndrome Respiratorio y Reproductivo Porcino , Vacunas , Porcinos , Animales , Virus del Síndrome Respiratorio y Reproductivo Porcino/genética , Línea CelularRESUMEN
The accurate effluent prediction plays a crucial role in providing early warning for abnormal effluent and achieving the adjustment of feedforward control parameters during wastewater treatment. This study applied a dual-staged attention mechanism based on long short-term memory network (DA-LSTM) to improve the accuracy of effluent quality prediction. The results showed that input attention (IA) and temporal attention (TA) significantly enhanced the prediction performance of LSTM. Specially, IA could adaptively adjust feature weights to enhance the robustness against input noise, with R2 increased by 13.18%. To promote its long-term memory ability, TA was used to increase the memory span from 96 h to 168 h. Compared to a single LSTM model, the DA-LSTM model showed an improvement in prediction accuracy by 5.10%, 2.11%, 14.47% for COD, TP, and TN. Additionally, DA-LSTM demonstrated excellent generalization performance in new scenarios, with the R2 values for COD, TP, and TN increasing by 22.67%, 20.06%, and 17.14% respectively, while the MAPE values decreased by 56.46%, 63.08%, and 42.79%. In conclusion, the DA-LSTM model demonstrated excellent prediction performance and generalization ability due to its advantages of feature-adaptive weighting and long-term memory focusing. This has forward-looking significance for achieving efficient early warning of abnormal operating conditions and timely management of control parameters.
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Aguas Residuales , Eliminación de Residuos Líquidos/métodos , Redes Neurales de la ComputaciónRESUMEN
Every year human discharges about 350 million tons of plastic waste into the environment and can be projected to triple in 2060 without any attempts to change situation. From 1970 to 2019, an estimation of 130 million tons of plastic waste was accumulated into the rivers, lakes and sea, while only 27 % is recycled and utilized. Moreover, waste treatment plants in most places around the world are using out-of-date technology, may pose a threat to the health of the workers. Therefore, it is essential to modernize these systems for protecting human health. This paper proposes fine-tuning DETR, which applies Artificial Intelligent in plastic waste sorting system. Consequently, this study analyzed the applicability of fine-tuning DETR in the domain of plastic waste categorization and its potential drawbacks. For fair experiment and evaluation, model candidates were trained and evaluated on an industrial plastic waste dataset. The fine-tuning DETR outperformed other candidates in the context of critical indicators, from accuracy (25.1 mAP), processing speed (28 FPS) to computational cost (GFLOPs 86). Furthermore, fine-tuning DETR possesses the capability of autonomous operation without requiring human intervention, distinguishing this candidate from other prevalent algorithms. Our research demonstrates that, fine-tuning DETR specifically and Transformer-based algorithms in general, are entirely suitable and hold significant potential for large-scale application in holistic plastic waste sorting systems.
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Piperazinas , Plásticos , Reciclaje , Humanos , Residuos IndustrialesRESUMEN
Porcine reproductive and respiratory syndrome virus (PRRSV) is an important pathogen that causes huge economic losses to the global pig industry. Nonstructural protein 7α (NSP7α) of PRRSV is highly conserved among different lineages of PRRSV and could be a potential target for the development of detection methods. In this study, NSP7α was expressed in prokaryote (Escherichia coli) and purified. An NSP7α-ab-ELISA detection method was established, the NSP7α-ab-ELISA has 93.1 % coincidence rate with IDEXX PRRS X3 ab test kit. NSP7α antibody was detected in pig serum by ELISA 14 days following PRRSV infection. Three monoclonal antibodies (4H9, 3F2, and C10) against NSP7α prepared by a hybridoma technique were used for epitope mapping by indirect immunofluorescence. The 4H9, 3F2, and C10 antibodies all recognized the C-terminal 72-149 amino acid region of NSP7α. 4H9 reacted with amino acids 135-143, but 3F2 and C10 did not react with any truncated polypeptide. In addition, by using the monoclonal antibodies, NSP7α was localized solely in the cytoplasm, while the N protein was distributed in the cytoplasm and nucleus. The collective findings of the antigenicity and epitope of NSP7α will be helpful for understanding the antigenicity of NSP7α and developing PRRSV diagnostic methods.
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Síndrome Respiratorio y de la Reproducción Porcina , Virus del Síndrome Respiratorio y Reproductivo Porcino , Animales , Porcinos , Mapeo Epitopo , Anticuerpos Antivirales , Anticuerpos Monoclonales , Escherichia coliRESUMEN
For insulated gate bipolar transistor (IGBT) modules using wire bonding as the interconnection method, the main failure mechanism is cracking of the bonded interface. Studying the mechanical properties of the bonded interface is crucial for assessing the reliability of IGBT modules. In this paper, first, shear tests are conducted on the bonded interface to test the bonded interface's strength. Then, finite element-cohesive zone modeling (FE-CZM) is established to describe the mechanical behavior of the bonded interface. A novel machine learning (ML) architecture integrating a convolutional neural network (CNN) and a long short-term memory (LSTM) network is used to identify the shape and parameters of the traction separation law (TSL) of the FE-CZM model accurately and efficiently. The CNN-LSTM architecture not only has excellent feature extraction and sequence-data-processing abilities but can also effectively address the long-term dependency problem. A total of 1800 sets of datasets are obtained based on numerical computations, and the CNN-LSTM architecture is trained with load-displacement (F-δ) curves as input parameters and TSL shapes and parameters as output parameters. The results show that the error rate of the model for TSL shape prediction is only 0.186%. The performance metric's mean absolute percentage error (MAPE) is less than 3.5044% for all the predictions of the TSL parameters. Compared with separate CNN and LSTM architectures, the proposed CNN-LSTM-architecture approach exhibits obvious advantages in recognizing TSL shapes and parameters. A combination of the FE-CZM and ML methods in this paper provides a promising and effective solution for identifying the mechanical parameters of the bonded interfaces of IGBT modules.
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Euphorbia dentata (Euphorbiaceae), an invasive weed, is rarely eaten by herbivorous insects and could secrete a large amount of white latex, causing a serious threat to local natural vegetation, agricultural production and human health. In order to prevent this plant from causing more negative effects on humans, it is necessary to understand and utilize the chemical relationships between the latex of E. dentata and herbivorous insects. In this study, three new norsesquiterpenes (1-3), together with seven known analogues (4-10), were isolated and identified from the latex of E. dentata. All norsesquiterpenes (1-10) showed antifeedant and growth-inhibitory effects on H. armigera with varying levels, especially compounds 1 and 2. In addition, the action mechanisms of active compounds (1-3) were revealed by detoxifying enzyme (AchE, CarE, GST and MFO) activities and corresponding molecular docking analyses. Our findings provide a new idea for the development and utilization of the latex of E. dentata, as well as a potential application of norsesquiterpenes in botanical insecticides.
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Euphorbia , Látex , Humanos , Mecanismos de Defensa , Euphorbia/química , Helicoverpa armigera , Látex/química , Simulación del Acoplamiento Molecular , AnimalesRESUMEN
The effect of microplastics (MPs) retained in waste activated sludge (WAS) on anaerobic digestion (AD) performance has attracted more and more attention. However, their effect on thermophilic AD remains unclear. Here, the influence of polyvinyl chloride (PVC) MPs on methanogenesis and active microbial communities in mesophilic (37 °C) and thermophilic (55 °C) AD was investigated. The results showed that 1, 5, and 10 mg/L PVC MPs significantly promoted the cumulative methane yield in mesophilic AD by 5.62%, 7.36%, and 8.87%, respectively, while PVC MPs reduced that in thermophilic AD by 13.30%, 18.82%, and 19.99%, respectively. Moreover, propionate accumulation was only detected at the end of thermophilic AD with PVC MPs. Microbial community analysis indicated that PVC MPs in mesophilic AD enriched hydrolytic and acidifying bacteria (Candidatus Competibacter, Lentimicrobium, Romboutsia, etc.) together with acetoclastic methanogens (Methanosarcina, Methanosaeta). By contrast, most carbohydrate-hydrolyzing bacteria, propionate-oxidizing bacterium (Pelotomaculum), and Methanosarcina were inhibited by PVC MPs in thermophilic AD. Network analysis further suggested that PVC MPs significantly changed the relationship of key microorganisms in the AD process. A stronger correlation among the above genera occurred in mesophilic AD, which may promote the methanogenic performance. These results suggested that PVC MPs affected mesophilic and thermophilic AD of WAS via changing microbial activities and interaction.
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Microplásticos , Aguas del Alcantarillado , Aguas del Alcantarillado/microbiología , Anaerobiosis , Plásticos , Propionatos , Reactores Biológicos , Bacterias , Metano , TemperaturaRESUMEN
Introduction: Solanum rostratum, an annual malignant weed, has seriously damaged the ecological environment and biodiversity of invasion area. This alien plant gains a competitive advantage by producing some new phytotoxic substances to inhibit the growth of native plants, thus achieving successful invasion. However, the chemical structures, inhibitory functions and action mechanisms of phytotoxic substances of S. rostratum remain unclear. Methods: In this study, to clarify the chemical structures of phytotoxic substances from S. rostratum, we isolated phenylpropanoid amides from the plant. Their structures were identified by comprehensive HR-ESIMS, NMR and ECD data. And the inhibitory functions of isolated phenylpropanoid amides on one model plant (Arabidopsis thaliana) were also investigated. In addition, the action mechanisms of active phenylpropanoid amides were revealed by antioxidant-related enzymes [Catalase (CAT), Peroxidase (POD), Superoxide dismutase (SOD)] activities and corresponding molecular docking analyses. Results and Discussion: Phytochemical research on the whole plant of S. rostratum led to the isolation and identification of four new phenylpropanoid amides (1-4), together with two known analogues (5-6). All the compounds showed phytotoxic effects with varying levels on the seed germination and root elongation of one model plant (Arabidopsis thaliana), especially compound 2 and 4. Likewise, compounds 2 and 4 displayed potent inhibitory effects on antioxidant-related enzyme (POD). In addition, compounds 2 and 4 formed common conventional hydrogen bonds with residues Ala34 and Ser35 in POD revealed by molecular docking analyses. These findings not only helped to reveal the invasion mechanism of S. rostratum from the perspective of "novel weapons hypothesis", but also opened up new ways for the exploitation and utilization of S. rostratum.
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Endothelial dysfunction is a key early link in the pathogenesis of atherosclerosis, and the accumulation of senescent vascular endothelial cells causes endothelial dysfunction. Phosphoenolpyruvate (PEP), which is a high-energy glycolytic intermediate, protects against ischemia-reperfusion injury in isolated rat lung, heart, and liver tissue by quickly providing ATP. However, it was reported that serum PEP concentrations are 13-fold higher in healthy elderly compare to the young. Unlike that of other cell types, the energy required for the physiological function of endothelial cells is mainly derived from glycolysis. Recently, it is unclear whether circulating accumulation of PEP affects endothelial cell function. In this study, we found for the first time that 50-250 µM of PEP significantly promoted THP-1 monocyte adhesion to human umbilical vein endothelial cells (HUVECs) through increased expression of vascular endothelial adhesion factor 1 (VCAM1) and intercellular adhesion factor 1 (ICAM1) in HUVECs. Meanwhile, 50-250 µM of PEP decreased the expression of endothelial nitric oxide synthase (eNOS) and cellular level of nitric oxide (NO) in HUVECs. Moreover, PEP increased levels of ROS, enhanced the numbers of SA-ß-Gal-positive cells and upregulated the expression of cell cycle inhibitors such as p21, p16 and the phosphorylation level of p53 on Ser15, and the expression of proinflammatory factors including TNF-α, IL-1ß, IL-6, IL-8, IL-18 and MCP-1 in HUVECs. Furthermore, PEP increased both oxygen consumption rate (OCR) and glycolysis rate, and was accompanied by reduced NAD+/NADH ratios and enhanced phosphorylation levels of AMPKα (Thr172), p38 MAPK (T180/Y182) and NF-κB p65 (Ser536) in HUVECs. Notably, PEP had no significant effect on hepG2 cells. In conclusion, these results demonstrated that PEP induced dysfunction and senescence in vascular endothelial cells through stimulation of metabolic reprogramming.
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Senescencia Celular , Transducción de Señal , Ratas , Animales , Humanos , Anciano , Células Cultivadas , Fosfoenolpiruvato/metabolismo , Fosfoenolpiruvato/farmacología , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Células Endoteliales de la Vena Umbilical Humana/patologíaRESUMEN
Despite the elaborate varieties of iridescent colors in biological species, most of them are reflective. Here we show the rainbow-like structural colors found in the ghost catfish (Kryptopterus vitreolus), which exist only in transmission. The fish shows flickering iridescence throughout the transparent body. The iridescence originates from the collective diffraction of light after passing through the periodic band structures of the sarcomeres inside the tightly stacked myofibril sheets, and the muscle fibers thus work as transmission gratings. The length of the sarcomeres varies from ~1 µm from the body neutral plane near the skeleton to ~2 µm next to the skin, and the iridescence of a live fish mainly results from the longer sarcomeres. The length of the sarcomere changes by ~80 nm as it relaxes and contracts, and the fish shows a quickly blinking dynamic diffraction pattern as it swims. While similar diffraction colors are also observed in thin slices of muscles from non-transparent species such as the white crucian carps, a transparent skin is required indeed to have such iridescence in live species. The ghost catfish skin is of a plywood structure of collagen fibrils, which allows more than 90% of the incident light to pass directly into the muscles and the diffracted light to exit the body. Our findings could also potentially explain the iridescence in other transparent aquatic species, including the eel larvae (Leptocephalus) and the icefishes (Salangidae).
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Bagres , Sarcómeros , Animales , Iridiscencia , Miofibrillas , NataciónRESUMEN
One of the main failure modes of an insulated-gate bipolar transistor (IGBT) module is the reconstruction of an aluminum (Al) metallization layer on the surface of the IGBT chip. In this study, experimental observations and numerical simulations were used to investigate the evolution of the surface morphology of this Al metallization layer during power cycling, and both internal and external factors affecting the surface roughness of the layer were analyzed. The results indicate that the microstructure of the Al metallization layer evolves during power cycling, where the initially flat surface gradually becomes uneven, such that the roughness varies significantly across the IGBT chip surface. The surface roughness depends on several factors, including the grain size, grain orientation, temperature, and stress. With regard to the internal factors, reducing the grain size or orientation differences between neighboring grains can effectively decrease the surface roughness. With regard to the external factors, the reasonable design of the process parameters, a reduction in the stress concentration and temperature hotspots, and preventing large local deformation can also reduce the surface roughness.
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Nitrogen (N) is an important macronutrient and is comprehensively involved in the synthesis of secondary metabolites. However, the interaction between N supply and crop yield and the accumulation of effective constituents in an N-sensitive medicinal plant Panax notoginseng (Burkill) F. H. Chen is not completely known. Morphological traits, N use and allocation, photosynthetic capacity and saponins accumulation were evaluated in two- and three-year-old P. notoginseng grown under different N regimes. The number and length of fibrous root, total root length and root volume were reduced with the increase of N supply. The accumulation of leaf and stem biomass (above-ground) were enhanced with increasing N supply, and LN-grown plants had the lowest root biomass. Above-ground biomass was closely correlated with N content, and the relationship between root biomass and N content was negatives in P. notoginseng (r = -0.92). N use efficiency-related parameters, NUE (N use efficiency, etc.), NC (N content in carboxylation system component) and P n (the net photosynthetic rate) were reduced in HN-grown P. notoginseng. SLN (specific leaf N), Chl (chlorophyll), NL (N content in light capture component) increased with an increase in N application. Interestingly, root biomass was positively correlated with NUE, yield and P n. Above-ground biomass was close negatively correlated with photosynthetic N use efficiency (PNUE). Saponins content was positively correlated with NUE and P n. Additionally, HN improved the root yield of per plant compared with LN, but reduced the accumulation of saponins, and the lowest yield of saponins per unit area (35.71 kg·hm-2) was recorded in HN-grown plants. HN-grown medicinal plants could inhibit the accumulation of root biomass by reducing N use and photosynthetic capacity, and HN-induced decrease in the accumulation of saponins (C-containing metabolites) might be closely related to the decline in N efficiency and photosynthetic capacity. Overall, N excess reduces the yield of root and C-containing secondary metabolites (active ingredient) in N-sensitive medicinal species such as P. notoginseng.
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Panax notoginseng , Plantas Medicinales , Saponinas , Plantas Medicinales/metabolismo , Saponinas/metabolismo , Panax notoginseng/metabolismo , Nitrógeno/metabolismo , BiomasaRESUMEN
Ambrosia artemisiifolia, an invasive plant, has seriously harmed the agricultural production, native ecosystems and human health. Allelopathy is an important reason for the successful invasion of this alien plant. However, the chemical basis, action effects, action mechanism and release pathway of its allelopathy remain unclear. To address these problems, four sesquiterpenes (1-4), consisting of three new sesquiterpenes (1-2, 4), were isolated from the whole plant of A. artemisiifolia using a variety of column chromatography techniques, and identified using HR-ESIMS, 1D-NMR, 2D-NMR, and ECD. All the compounds exhibited different levels of inhibitory effects on three native plants (Setaria viridis, Digitaria sanguinalis, Chenopodium album) and one model plant (Arabidopsis thaliana), especially compound 1. In addition, the preliminary action mechanism of active compound 1 was revealed by FDA/PI staining assay. Furthermore, the allelopathic substances 1-3 were released into environment through the root secretion pathway by UPLC-MS/MS analyses.
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Phenol red and PEG-4000, the usual non-absorbable indicators, have non-negligible absorption problems in measuring water flux. mPEG-PR, combined phenol red with mPEG-4000, was first synthesized and could decrease absorption. However, its application has not been confirmed. The purpose of this study was to explore the applicability of mPEG-PR as a novel non-absorption indicator in the in situ single-pass intestinal perfusion (SPIP) experiment. Six model drugs (atenolol ranitidine, ibuprofen, ketoprofen, antipyrine, hydrochlorothiazide) were used to compare the accuracy of four measuring methods including phenol red, mPEG-PR, gravimetric, and non-corrected methods of correcting intestinal fluid transport. Moreover, we evaluated the correlations between the effective permeability coefficients (Peff) in rat and fraction dose absorbed (Fabs) in human, Peff in human, and apparent permeability coefficients (Papp) by the Ussing Chamber system using human tissue. Among these methods, mPEG-PR was the most reliable approach, which avoided the absorption of phenol red method and mucous shedding or water evaporation of gravimetric method. An excellent correlation was obtained between the Peff of rat and Fabs of human. Our results of this study indicated that mPEG-PR was a stable and accurate non-absorbable indicator to correct water flux in the in situ SPIP model, which could be developed to predict the human Fabs.