Search Results (61)

Pine wilt disease, a highly destructive forest disease with rapid spread, currently has no effective treatments. Infected pine trees usually die within a few months, causing severe damage to forest ecosystems. A rapid and accurate detection algorithm for diseased trees is crucial for curbing the spread of this disease. In recent years, the combination of drone remote sensing and deep learning has become the main methods of detecting and locating diseased trees. Previous studies have shown that increasing network depth cannot improve accuracy in this task. Therefore, a lightweight semantic segmentation model based on a CNN-Transformer hybrid architecture was designed in this study, named EVitNet. This segmentation model reduces network parameters while improving recognition accuracy, outperforming mainstream models. The segmentation IoU for discolored trees reached 0.713, with only 1.195 M parameters. Furthermore, considering the diverse and complex terrain where diseased trees are distributed, a fine-tuning model approach was adopted. After a small amount of training, the IoU on new samples increased from 0.321 to 0.735, greatly enhancing the practicality of the algorithm. The model’s segmentation speed in the task of discolored trees identification meets the requirements of real-time performance, and its accuracy exceeds that of mainstream semantic segmentation models. In the future, it is expected to be deployed on drones for real-time recognition, accelerating the entire process of discovering and locating infected trees. Full article

Background: Herein, we review the Cotton Top Tamarin (CTT), Saguinus oedipus, a unique spontaneous model for colorectal cancer (CRC). Despite its predisposition to inflammatory bowel disease (IBD) and frequent development of CRC, the CTT is adept at avoiding colorectal metastasis in the liver. In contrast, the common marmoset (CM), Callithrix jacchus, is a natural negative control, in that it also contracts IBD, but usually not CRC. We review our findings in these New World monkeys in terms of the expression of CEACAM adhesion models and their related molecules to contrast them with human disease. Methods: Specimens were collected from aforementioned monkey colorectal and other tissues, colonic washings, serum for analysis of tissue extraction, and colonic washings via ELISA, using a battery of antibodies. Fixed tissues were analyzed using immunohistochemistry and CEACAMs were extracted via Western blotting. Serum CEA levels were analyzed using ELISA, and DNA was extracted via a Bigblast genomics sequencing kit. Results: Serum CEA was significantly elevated in CTTs, and one-third of them die from CRC. Unlike others, we were unable to stain for CEA in tissues. The sialylated carbohydrate antigen recognized by monoclonal antibody (MAb) SPAN-1 does stain in 16.7% of CTT tissues, but the anti-aminoproteoglycan MAb, CaCo.3/61, stained 93.3% (OR70·00[CI6.5–754.5] p < 0.0001). The common CEA kits from Abbott and Roche were non-conclusive for CEA. We later adopted a CEA AIA-PACK from Tosoh Medics, which identified a 50 Kda band via Western blotting in humans and CTTs. The CEA levels were higher using the CEA AIA-PACK than the Pharmatrope kit (932 ± 690 versus 432 ± 407 ng/mL (p < 0.05)) in human patient colonic effluent, not statistically significant (NSS) for CTT extracts or effluent (733 ± 325 and 739 ± 401 ng/mL, respectively). It was suggested that the smaller CTT CEA moiety might lack components that facilitate the spread of liver metastasis. Later, using more specific CEA assays and increased numbers of specimens, we were able to show higher CEA serum expression in CTTs than in CMs (632.1 ± 306.1 vs. 81.6 ± 183.6, p < 0.005), with similar differences in the serum samples. Western blotting with the anti-CEA T84.66 MAb showed bands above 100 KDa in CTTs. The profiles in CTTs were similar to human patients with inflammatory bowel disease. We established that the CEA anchorage to the cell was a GPI-linkage, advantageous for the inhibition of differentiation and anoikis. With further CEA DNA analysis, we were able to determine at least five different mechanisms that may inhibit liver metastasis, mostly related to CEA, but later expanded this to seven, and increased the relationships to CEACAM1 and other related molecules. Recently, we obtained CTT liver mRNA transcriptomes that implicated several pathways of interest. Conclusions: With efforts spanning over three decades, we were able to characterize CEA and other changes that allow us to better understand the CTT phenomenon of liver metastasis inhibition. We are in the process of characterizing the CTT liver mRNA transcriptome to compare it with that of the common marmoset. Currently, liver CTT gene expression patterns suggest that ribosomes, lipoproteins, and antioxidant defense are related to differences between CTTs and CMs. Full article

Rift Valley fever (RVF) is a vector-borne zoonotic viral disease that causes abortion storms, fetal malformations, and neonatal mortality in livestock ruminants. In humans, RVF can lead to hemorrhagic fever, encephalitis, retinitis, or blindness, and about 1% of patients die. Since there are no registered vaccines for human use, developing RVF vaccines for use in animals is crucial to protect animals and prevent the spread of the virus from infecting humans. We recently developed a live bovine herpesvirus type 1 quadruple gene-mutant vector (BoHV-1qmv) that lacks virulence and immunosuppressive properties. Further, we engineered a BoHV-1qmv-vectored subunit Rift Valley fever virus (RVFV) vaccine (BoHV-1qmv Sub-RVFV) for cattle, in which a chimeric polyprotein coding for the RVFV Gc, Gn, and bovine granulocyte–macrophage colony-stimulating factor (GMCSF) proteins is fused but cleaved proteolytically in infected cells into individual membrane-anchored Gc and secreted Gn-GMCSF proteins. Calves vaccinated with the BoHV-1qmv Sub-RVFV vaccine generated moderate levels of RVFV-specific serum-neutralizing (SN) antibodies and cellular immune responses. In the current study, we repurposed the BoHV-1qmv Sub-RVFV for sheep by replacing the RVFV Gc and Gn ORF sequences codon-optimized for bovines with the corresponding ovine-codon-optimized sequences and by fusing the sheep GM-CSF ORF sequences with the Gn ORF sequence. A combined primary intranasal-plus-subcutaneous primary immunization induced a moderate level of BoHV-1 (vector)- and vaccine strain MP12-specific SN antibodies and MP-12-specific cellular immune responses. Notably, an intranasal booster vaccination after 29 days triggered a rapid (within 7 days) rise in MP-12-specific SN antibody titers. Therefore, the BoHV-1qmv-vectored subunit RVFV vaccine is safe and highly immunogenic in sheep and can potentially be an efficient subunit vaccine for sheep against RVFV. Full article

Rotavirus is an enteric virus that leads to 200,000 deaths worldwide every year. The live-cell imaging evaluating rotavirus infection of MA104 cells revealed that rotavirus replication and spread occurs in a spatially controlled manner. Specifically, following initial rotavirus infection, the infected cells die, and the second round of infection occurs in the restricted area surrounding the initially infected cell. Interestingly, we found that the time required to establish the secondary infection is shorter compared to the time required for the initial infection. To determine if this increase in the kinetic of secondary infection was due to the early release of viruses or priming of the cells that are infected during the secondary infection, we used a combination of live-cell microscopy, trypsin neutralization assays, and the pharmacological inhibition of calcium signaling. Together, our results show that the second round of infection required rotavirus to be released and accessible to extracellular proteases. In addition, we found that the calcium wave induced upon rotavirus infection was critical for initial infection but did not play a role in the establishment of a secondary infection. Finally, we uncovered that high viral titers released from the initial infection were sufficient to accelerate the rate of the secondary infection. Full article

To thrive as a successful weed in natural pastures, a plant must have not only highly competitive ability, but also the resilience to endure environmental stress and rapidly reclaim space once those stressors diminish and the other non-stress-tolerant plants die. Acanthostyles buniifolius [(Hook. ex Hook. & Arn.) R.M.King & H.Rob.], known as chirca, is a widely spread weed in South American natural pastures. It is known for its remarkable ability to withstand environmental stress and flourish in environments with prevalent stressors. The study evaluated the memory effect of water stress (drought) in chirca plants. The experiment was conducted in a greenhouse in a randomized block design with three replications. Treatments included Control = control plants without water deficit kept at 100% of the soil water-holding capacity (WHC); Primed plants = plants that were primed with water stress at 141 days after emergence (DAE) and received recurrent stress at 164 DAE; Naïve plants: plants that only experienced water stress at 164 DAE. To reach water stress, plants were not watered until the soil reached 15% of the soil’s WHC, which occurred ten days after water suppression in the priming stress and nine days after water suppression in the second stress. During periods without restriction, the pots were watered daily at 100% of the WHC. Primed plants exposed to water deficit better-maintained water status compared to the naïve plants; glycine betaine is an important defense mechanism against water deficit in chirca; naïve plants have a higher concentration of proline than plants under recurrent stress, demonstrating the greater need for protection against oxidative damage and needs greater osmotic regulation. Recurrent water deficits can prepare chirca plants for future drought events. These results show that chirca is a very adaptative weed and may become a greater threat to pastures in South America due to climate change, especially if drought becomes more frequent and severe. Full article

Slot-die coating is widely used in the preparation of negative electrodes for lithium batteries. The thickness of the negative electrode has a significant influence on the battery performance and lifespan, and different manufacturers have different requirements for its thickness. In order to reduce the waste caused by trial and error in the electrode preparation process, a prediction model for the negative electrode thickness was established and verified through simulation and experiments. Based on the Landau–Levich film equation and the Ruschak model, a high-precision prediction model was constructed by taking into account the influence of factors’, such as temperature and slurry, spreading characteristics on the coating thickness. The minimum coating thickness and its influencing factors were explored. Meanwhile, the simulation analysis of the coating thickness was performed, and the theoretical values of three common process parameters were compared with the simulation results, showing a deviation of only 2.9%. An experiment on predicting the thickness of the negative electrode of lithium batteries was conducted. Thickness measurements were performed on the samples prepared through the experiment and compared with theoretical values. The accuracy rate of this thickness prediction model can reach 98.75%. Full article

Huanglongbing is one of the most destructive diseases of citrus worldwide. Infected trees die due to the absence of practical cures. Thus, the removal of HLB-infected trees is one of the principal HLB managements for the regulation of disease spread. Here, we propose a non-destructive HLB detection method based on hyperspectral leaf reflectance. In total, 72 hyperspectral leaf images were collected in an HLB-invaded citrus orchard in Thailand and each image was visually distinguished into either any HLB symptom appearance (symptomatic) or no symptoms (asymptomatic) on the leaf. Principal component analysis was applied on the hyperspectral data and revealed 16 key wavelengths at red-edge to near-infrared regions (715, 718, 721, 724, 727, 730, 733, 736, 930, 933, 936, 939, 942, 945, 957, and 997 nm) that were characteristically differentiated in the symptomatic group. Seven models learnt on the spectral data at these 16 wavelengths were examined for the potential to separate these two image groups: random forest, decision tree, support vector machine, k-nearest neighbor, gradient boosting, logistic regression, linear discriminant. F1-score was employed to select the best-fit model to distinguish the two categories: random forest achieved the best score of 99.8%, followed by decision tree and k-nearest neighbor. The reliability of the visual grouping was evaluated by nearest neighbor matching and permutation test. These three models separated the two image categories as precisely as PCR results, indicating their potential as alternative tool instead of PCR. Full article

White mold, caused by the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary, is a significant biotic stress impacting horticultural and field crops worldwide. This disease causes plants to wilt and ultimately die, resulting in considerable yield losses. This monocyclic disease progresses through a single infection cycle involving basal infections from myceliogenically germinated sclerotia or aerial infections initiated by ascospores from carpogenically germinated sclerotia. The pathogen has a homothallic mating system with a weak population structure. Relatively cool temperatures and extended wetness are typical conditions for spreading the disease. Each stage of infection triggers a cascade of molecular and physiological events that underpin defense responses against S. sclerotiorum. Molecular markers can help rapid diagnosis of this disease in plants. Effective management strategies encompass altering the crop microclimate, applying fungicides, reducing inoculum sources, and developing resistant plant varieties. Integrated approaches combining those strategies often yield the best results. This review discusses the latest insights into the biology, epidemiology, infection mechanisms, and early detection of white mold. This review also aims to provide comprehensive guidelines for sustainable management of this destructive disease while reducing the use of excessive pesticides in crop fields. Full article

In this work, electrostatic minimum quantity lubrication (EMQL) has been applied in grinding. When the droplets were charged, it could promote penetrability in the processing area. The electric field formed between the charged droplets and the surface of Cr12 die steel could affect the hardness of the workpiece surface. The grinding mechanism of EMQL has been revealed under different charging voltage by analyzing the wetting angle of droplets and the hardness of Cr12 surface. The reduction of grinding force (11.5% to 49%), surface roughness (10% to 22.1%), and the increase in grinding ratio (1.9% to 27.3%) and surface quality of EMQL under various charging voltages were studied. The results showed that the wetting angle decreased when the droplets were charged. Compared to MQL, the charged lubricant droplets with better penetrability are easier to penetrate and spread on the contact surface between the grinding wheel and the workpiece, thereby improving the lubrication of the friction interface and obtaining better grinding performance. Moreover, we also found that the positively charged EMQL not only effectively improves the penetrability of droplets but reduces the hardness of the Cr12 surface. Thus, the grinding performances under positively charged EMQL are always better than these under negatively charged when grinding Cr12. Full article

Traditionally, structural wire is characterized by a homogeneous microstructure, where the average grain size in different parts of the wire is uniform. According to the classical Hall–Petch relationship, a homogeneous polycrystalline metal can be strengthened by decreasing the average grain size since an increase in the volume fraction of grain boundaries will further impede the motion of dislocations. However, a decrease in the grain size inevitably leads to a decrease in the ductility and deformability of the material due to limited dislocation mobility. Putting a gradient microstructure into the wire has promising potential for overcoming the compromise between strength and ductility. This is proposed a new combined technology in this paper in order to obtain a gradient microstructure. This technology consists of deforming the wire in a rotating equal-channel step die and subsequent traditional drawing. Deformation of copper wire with a diameter of 6.5 mm to a diameter of 5.0 mm was carried out in three passes at room temperature. As a result of such processing, a gradient microstructure with a surface nanostructured layer (grain size ~400 nm) with a gradual increase in grain size towards the center of the wire was obtained. As a result, the microhardness in the surface zone was 1150 MPa, 770 Mpa in the neutral zone, and 685 MPa in the central zone of the wire. Such a symmetrical spread of microhardness, observed over the entire cross-section of the rod, is a direct confirmation of the presence of a gradient microstructure in deformed materials. The strength characteristics of the wire were doubled: the tensile strength increased from 335 MPa to 675 MPa, and the yield strength from 230 MPa to 445 MPa. At the same time, the relative elongation decreased from 20% to 16%, and the relative contraction from 28% to 23%. Despite the fact that the ductility of copper is decreased after cyclic deformation, its values remain at a fairly high level. The validity of all results is confirmed by numerous experiments using a complex of traditional and modern research methods, which include optical, scanning, and transmission microscopy; determination of mechanical properties under tension; and measurement of hardness and electrical resistance. These methods allow reliable interpretation of the fine microstructure of the wire and provide information on its strength, plastic, and electrical properties. Full article

This study implements a minded approach to studying Ebola virus disease (EVD) by dividing the infected population into aware and unaware groups and including a hospitalized compartment. This offers a more detailed understanding of illness distribution, potential analyses, and the influence of public knowledge. The findings might improve healthcare budget apportionment, public health policy, and contest Ebola and related infections. In this study, we fully observe the new model $SEIHR$ that we have constructed. We start by outlining the essential concepts of the model and confirming its mathematical reliability. Next, we calculate the fundamental reproductive number $\left(R_0\right)$, which is critical for appreciating how the infection spreads and how effective treatments might be. We also study stability analysis, which looks at when the disease may decline or become chronic. Furthermore, we exhibit the occurrence of bifurcation in the EVD Epidemic Model and perform a sensitivity analysis of $\left(R_0\right)$. The main findings of this study show that for $R_0<1$, the disease-free equilibrium, is globally stable, meaning the disease will die out, whereas for $R_0>1$, the endemic equilibrium is stable, meaning the disease persists. Additionally, the sensitivity analysis reveals that the most influential parameters in controlling $R_0$ are the transmission rate and the recovery rate, which could guide effective intervention strategies. Finally, we use numerical simulations so that out outcomes are more significant. Full article

This study investigates the influence of pre-corrosion damage on the fatigue behavior of AlSi10MgMn high-pressure die-cast specimens, using the statistical distribution of corrosion depths. The analysis is conducted on two different surface conditions: an unmachined rough surface ($R_a=5.05$$\mathsf{\mu }\mathrm{m}$) and a machined, polished surface ($R_a=0.25$$\mathsf{\mu }\mathrm{m}$). For the unmachined specimens, the corrosive damage manifests as homogeneously spread localized corrosion, whereas the polished specimens exhibit less uniform but deeper corrosion. The average corrosion depth of the polished specimens is found to be slightly higher (313 $\mathsf{\mu }\mathrm{m}$ compared to 267 $\mathsf{\mu }\mathrm{m}$) with a broader depth distribution. Specimens are tested under a constant bending load amplitude in laboratory conditions at a stress ratio of $R=0$ until fracture. A fracture mechanics-based methodology is developed to assess the remaining fatigue life of corroded specimens, utilizing short and long crack fracture mechanical parameters derived from SENB specimens. This model incorporates a thickness reduction of the critical specimen cross-section based on the corrosion depth distribution and combines it with a small initial crack of the intrinsic defect size ($a_{eff}=14$$\mathsf{\mu }\mathrm{m}$). Regardless of the surface condition, using the most frequent corrosion depth for thickness reduction provides a good estimate of the long-life fatigue strength, while using the 90th percentile depth allows for a conservative assessment. Full article

Fusarium spp. can cause root rot in alfalfa, leading to the death of the whole plant, which seriously affects the yield and quality of alfalfa. This study used a Fusarium acuminatum strain labeled with green fluorescent protein (GFP) to observe the infection process of F. acuminatum on alfalfa by confocal fluorescence microscopy. The aim of this study was to reveal the infection mechanism of alfalfa Fusarium root rot at the cellular histological level. The results showed that conidia of F. acuminatum attached to the surface of the root and germinated at one day post-inoculation, the mycelium then entered the vascular bundle tissue of the alfalfa root at 5 days post-inoculation, reached the base of the plant stem at 14 days post-inoculation, and colonized the stem of the first and second compound leaf at 28 and 49 days post-inoculation, respectively. Moreover, the experiment, which sprayed a spore suspension, showed that the conidia of F. acuminatum could spread through the air to infect the pericarp and seed coat tissue of the pod. For the first time, we report the infection process of alfalfa Fusarium root rot caused by F. acuminatum and clarify that F. acuminatum can initially infect the root tissue of alfalfa, colonize the bottom stem of the plant through systematic infection, and eventually cause the plant to wilt and die. The results reveal the infection mechanism of F. acuminatum at the cell level via histology and provide theoretical support for the development of control strategies and key control technologies for alfalfa root rot. Full article

The reproduction number, $R_0$, is an important parameter in epidemic models. It is interpreted as the average number of new cases resulted from each infected individual during the course of infection. In this paper, the $R_0$ estimates since the outbreak of COVID-19 till 10 August 2020 for eight countries were computed using the package R{eSIR}. The computed values were examined and compared with the daily $R_0$ estimates obtained by a static SIR model by aligning the days of infection, assuming a fixed number of days for the infected person to become confirmed/recover/die. The results showed that running R{eSIR} to obtain $R_0$ estimates provided an easy mean of exploring epidemic data. Care must be taken in the interpretation of $R_0$ as a measure of severity of the spread of an epidemic. Other factors, such as imported cases, need to be considered. Full article

We study epidemic spreading in complex networks by a multiple random walker approach. Each walker performs an independent simple Markovian random walk on a complex undirected (ergodic) random graph where we focus on the Barabási–Albert (BA), Erdös–Rényi (ER), and Watts–Strogatz (WS) types. Both walkers and nodes can be either susceptible (S) or infected and infectious (I), representing their state of health. Susceptible nodes may be infected by visits of infected walkers, and susceptible walkers may be infected by visiting infected nodes. No direct transmission of the disease among walkers (or among nodes) is possible. This model mimics a large class of diseases such as Dengue and Malaria with the transmission of the disease via vectors (mosquitoes). Infected walkers may die during the time span of their infection, introducing an additional compartment D of dead walkers. Contrary to the walkers, there is no mortality of infected nodes. Infected nodes always recover from their infection after a random finite time span. This assumption is based on the observation that infectious vectors (mosquitoes) are not ill and do not die from the infection. The infectious time spans of nodes and walkers, and the survival times of infected walkers, are represented by independent random variables. We derive stochastic evolution equations for the mean-field compartmental populations with the mortality of walkers and delayed transitions among the compartments. From linear stability analysis, we derive the basic reproduction numbers $R_M,R_0$ with and without mortality, respectively, and prove that $R_M<R_0$. For $R_M,R_0>1$, the healthy state is unstable, whereas for zero mortality, a stable endemic equilibrium exists (independent of the initial conditions), which we obtained explicitly. We observed that the solutions of the random walk simulations in the considered networks agree well with the mean-field solutions for strongly connected graph topologies, whereas less well for weakly connected structures and for diseases with high mortality. Our model has applications beyond epidemic dynamics, for instance in the kinetics of chemical reactions, the propagation of contaminants, wood fires, and others. Full article