Differences in Oligomerization of the SARS-CoV-2 Envelope Protein, Poliovirus VP4, and HIV Vpu.

Viroporins constitute a class of viral membrane proteins with diverse roles in the viral life cycle. They can self-assemble and form pores within the bilayer that transport substrates, such as ions and genetic material, that are critical to the viral infection cycle. However, there is little known about the oligomeric state of most viroporins. Here, we use native mass spectrometry in detergent micelles to uncover the patterns of oligomerization of the full-length SARS-CoV-2 envelope (E) protein, poliovirus VP4, and HIV Vpu. Our data suggest that the E protein is a specific dimer, VP4 is exclusively monomeric, and Vpu assembles into a polydisperse mixture of oligomers under these conditions. Overall, these results revealed the diversity in the oligomerization of viroporins, which has implications for the mechanisms of their biological functions as well as their potential as therapeutic targets.

Socially cued anticipatory adjustment of female signalling effort in a moth.

Juvenile population density has profound effects on subsequent adult development, morphology and reproductive investment. Yet, little is known about how the juvenile social environment affects adult investment into chemical sexual signalling. Male gumleaf skeletonizer moths, Uraba lugens, facultatively increase investment into antennae (pheromone receiving structures) when reared at low juvenile population densities, but whether there is comparable adjustment by females into pheromone investment is not known. We investigate how juvenile population density influences the 'calling' (pheromone-releasing) behaviour of females and the attractiveness of their pheromones. Female U. lugens adjust their calling behaviour in response to socio-sexual cues: adult females reared in high juvenile population densities called earlier and for longer than those from low juvenile densities. Juvenile density also affected female pheromonal attractiveness: Y-maze olfactometer assays revealed that males prefer pheromones produced by females reared at high juvenile densities. This strategic investment in calling behaviour by females, based on juvenile cues that anticipate the future socio-sexual environment, likely reflects a response to avoid mating failure through competition with neighbouring signallers.

Interface stabilization via lithium bis(fluorosulfonyl)imide additive as a key for promoted performance of graphite‖LiCoO2 pouch cell under -20 ○C.

The effects of lithium bis(fluorosulfonyl)imide, Li[N(SO2F)2] (LiFSI), as an additive on the low-temperature performance of graphite‖LiCoO2 pouch cells are investigated. The cell, which includes 0.2M LiFSI salt additive in the 1M lithium hexafluorophosphate (LiPF6)-based conventional electrolyte, outperforms the one without additive under -20 °C and high charge cutoff voltage of 4.3 V, delivering higher discharge capacity and promoted rate performance and cycling stability with the reduced change in interfacial resistance. Surface analysis results on the cycled LiCoO2 cathodes and cycled graphite anodes extracted from the cells provide evidence that a LiFSI-induced improvement of high-voltage cycling stability at low temperature originates from the formation of a less resistive solid electrolyte interphase layer, which contains plenty of LiFSI-derived organic compounds mixed with inorganics that passivate and protect the surface of the cathode and anode from further electrolyte decomposition and promotes Li+ ion-transport kinetics despite the low temperature, inhibiting Li metal-plating at the anode. The results demonstrate the beneficial effects of the LiFSI additive on the performance of a lithium-ion battery for use in battery-powered electric vehicles and energy storage systems in cold climates and regions.

Convolutional Neural Networks for Image-Based Corn Kernel Detection and Counting.

Precise in-season corn grain yield estimates enable farmers to make real-time accurate harvest and grain marketing decisions minimizing possible losses of profitability. A well developed corn ear can have up to 800 kernels, but manually counting the kernels on an ear of corn is labor-intensive, time consuming and prone to human error. From an algorithmic perspective, the detection of the kernels from a single corn ear image is challenging due to the large number of kernels at different angles and very small distance among the kernels. In this paper, we propose a kernel detection and counting method based on a sliding window approach. The proposed method detects and counts all corn kernels in a single corn ear image taken in uncontrolled lighting conditions. The sliding window approach uses a convolutional neural network (CNN) for kernel detection. Then, a non-maximum suppression (NMS) is applied to remove overlapping detections. Finally, windows that are classified as kernel are passed to another CNN regression model for finding the ( x , y ) coordinates of the center of kernel image patches. Our experiments indicate that the proposed method can successfully detect the corn kernels with a low detection error and is also able to detect kernels on a batch of corn ears positioned at different angles.

The Optimization of a Novel Hydrogel-Egg White-Alginate for 2.5D Tissue Engineering of Salivary Spheroid-Like Structure.

Hydrogels have been used for a variety of biomedical applications; in tissue engineering, they are commonly used as scaffolds to cultivate cells in a three-dimensional (3D) environment allowing the formation of organoids or cellular spheroids. Egg white-alginate (EWA) is a novel hydrogel which combines the advantages of both egg white and alginate; the egg white material provides extracellular matrix (ECM)-like proteins that can mimic the ECM microenvironment, while alginate can be tuned mechanically through its ionic crosslinking property to modify the scaffold's porosity, strength, and stiffness. In this study, a frozen calcium chloride (CaCl2) disk technique to homogenously crosslink alginate and egg white hydrogel is presented for 2.5D culture of human salivary cells. Different EWA formulations were prepared and biologically evaluated as a spheroid-like structure platform. Although all five EWA hydrogels showed biocompatibility, the EWA with 1.5% alginate presented the highest cell viability, while EWA with 3% alginate promoted the formation of larger size salivary spheroid-like structures. Our EWA hydrogel has the potential to be an alternative 3D culture scaffold that can be used for studies on drug-screening, cell migration, or as an in vitro disease model. In addition, EWA can be used as a potential source for cell transplantation (i.e., using this platform as an ex vivo environment for cell expansion). The low cost of producing EWA is an added advantage.

Insect Antennal Morphology: The Evolution of Diverse Solutions to Odorant Perception.

Chemical communication involves the production, transmission, and perception of odors. Most adult insects rely on chemical signals and cues to locate food resources, oviposition sites or reproductive partners and, consequently, numerous odors provide a vital source of information. Insects detect these odors with receptors mostly located on the antennae, and the diverse shapes and sizes of these antennae (and sensilla) are both astonishing and puzzling: what selective pressures are responsible for these different solutions to the same problem - to perceive signals and cues? This review describes the selection pressures derived from chemical communication that are responsible for shaping the diversity of insect antennal morphology. In particular, we highlight new technologies and techniques that offer exciting opportunities for addressing this surprisingly neglected and yet crucial component of chemical communication.

Effects of the c-Si/a-SiO2 interfacial atomic structure on its band alignment: an ab initio study.

The crystalline-Si/amorphous-SiO2 (c-Si/a-SiO2) interface is an important system used in many applications, ranging from transistors to solar cells. The transition region of the c-Si/a-SiO2 interface plays a critical role in determining the band alignment between the two regions. However, the question of how this interface band offset is affected by the transition region thickness and its local atomic arrangement is yet to be fully investigated. Here, by controlling the parameters of the classical Monte Carlo bond switching algorithm, we have generated the atomic structures of the interfaces with various thicknesses, as well as containing Si at different oxidation states. A hybrid functional method, as shown by our calculations to reproduce the GW and experimental results for bulk Si and SiO2, was used to calculate the electronic structure of the heterojunction. This allowed us to study the correlation between the interface band characterization and its atomic structures. We found that although the systems with different thicknesses showed quite different atomic structures near the transition region, the calculated band offset tended to be the same, unaffected by the details of the interfacial structure. Our band offset calculation agrees well with the experimental measurements. This robustness of the interfacial electronic structure to its interfacial atomic details could be another reason for the success of the c-Si/a-SiO2 interface in Si-based electronic applications. Nevertheless, when a reactive force field is used to generate the a-SiO2 and c-Si/a-SiO2 interfaces, the band offset significantly deviates from the experimental values by about 1 eV.

A simple and highly sensitive method of measuring heme oxygenase activity.

Heme oxygenase (HO) is a rate-limiting step of heme degradation, which catalyzes the conversion of heme into biliverdin, iron, and CO. HO has been characterized in microorganisms, insects, plants, and mammals. Previously used assays of HO activity were complicated and had low sensitivity. We found that the use of an eel bilirubin-bound fluorescent protein, UnaG, can achieve a highly sensitive and simple assay of HO activity. Using several enzyme sources including human culture cells, homogenates of plant tissues, and recombinant yeast HO, data were successfully obtained. The present method can facilitate the examination of HO in various organisms.

Electronic structures and current conductivities of B, C, N and F defects in amorphous titanium dioxide.

Although titanium dioxide (TiO2) has been extensively studied and widely used in energy and environmental areas, the amorphous form and its related defect properties are poorly understood. Recent studies, however, have emphasized the crucial role of amorphousness in producing competitively good performances in photochemical applications. In this work we have investigated for the first time the effects of various dopants (B, C, N and F) on charge carrier transport in amorphous titanium dioxide (a-TiO2), given that doping is a common technique used to tune the electronic properties of semiconductors, and that the existence of these impurities could also be unintentionally introduced during the synthesis process. The a-TiO2 model was obtained using a classical molecular dynamics method, followed by density-functional theory calculations (DFT + U, with Hubbard correction term U) on electronic structures and defect states. The formation of these impurity defects in a-TiO2 was found to be energetically more favorable by several eV than their crystal counterparts (in rutile). The contributions of these defect states to the charge transfer processes were examined by means of Marcus theory.

Oxygen vacancy and hole conduction in amorphous TiO2.

The amorphous titanium dioxide (a-TiO2) has drawn attention recently due to the finding that it holds promise for coating conventional photoelectrodes for corrosion protection while still allowing the holes to transport to the surface. The mechanism of hole conductivity at a level much higher than the edge of the valence band is still a mystery. In this work, an amorphous TiO2 model is obtained from molecular dynamics employing the "melt-and-quench" technique. The electronic properties, polaronic states and the hole conduction mechanism in amorphous structure were investigated by means of density functional theory with Hubbard's energy correction (DFT + U) and compared to those in crystalline (rutile) TiO2. The formation energy of the oxygen vacancy was found to reduce significantly (by a few eV) upon amorphization. Our theoretical study suggested that the oxygen vacancies and their defect states provide hopping channels, which are comparable to experimental observations and could be responsible for hole conduction in the "leaky" TiO2 recently discovered for the photochemical water-splitting applications.

DFT+U studies of Cu doping and p-type compensation in crystalline and amorphous ZnS.

Zinc sulfide is an excellent candidate for the development of a p-type transparent conducting material that has great demands in solar energy and optoelectronic applications. Doping with Cu is one potential way to make ZnS p-type while preserving its optical transparency for the solar spectrum; however, this is limited by the extremely low solubility of Cu in ZnS and charge compensation mechanisms that eliminate the p-type characteristics. These mechanisms are different in crystalline (c-ZnS) and amorphous structures (a-ZnS), leading to different tendencies of doping Cu in these two ZnS phases, as well as the feasibility to form the p-type material. In this work, we have carried out fundamental studies of Cu doping in both c-ZnS and a-ZnS, using the continuous random network model and density functional theory with Hubbard's energy correction (DFT+U). The formation of a complex that contains two CuZn and one S vacancy is highly favorable in both phases. The local environment of this charge-compensated Cu complex obtained by DFT calculations agrees well with the previous EXAFS measurements. The incorporation of Cu into a-ZnS, on the one hand, is more tolerable compared to its crystal counterparts (zincblende), indicating possible higher Cu concentration. On the other hand, there is also another intrinsic mechanism to compensate the p-type characteristics in a-ZnS: the formation of the covalent S-S "dumbbell" units. This reconstruction of the local structure to form a S-S bond could occur spontaneously, thus making the p-type doping for ZnS challenging even in the amorphous phase.

Formative Evaluation of a Text Messaging Intervention to Promote Varenicline Adherence Among Tobacco-Dependent Persons with HIV.

Few published studies describe processes in the development of mobile health interventions. This study reports data from a formative evaluation of a text messaging intervention being developed to increase adherence to smoking cessation medication (varenicline) among tobacco-dependent persons with HIV/AIDS. Four focus groups were conducted (N = 29) using a mixed-methods approach to assess: (a) beliefs and preferences regarding the use of varenicline, (b) preferences for receiving tobacco-related texts, and (c) the acceptability of draft text messages. Themes that emerged from the focus groups were that (a) participants were cautious and wanted to discuss varenicline carefully with health care providers, (b) participants preferred simple messages that were positive and encouraging, (c) messages should emphasize tobacco cessation and not varenicline adherence, and (d) texts would serve as a reminder about goals and foster support and connectedness with the health care team. Overall, 47 out of the 100 messages received a grade of C or less (rated on a 5-point grade scale: A, B, C, D, or F), the majority of which focused on medication adherence. All participants reported that they were likely to read the messages. The majority (64%) indicated that they preferred receiving 2 or more messages per day. Gathering systematic participant feedback provides critical input in intervention planning.

Gelatin hydrogel impregnated with platelet-rich plasma releasate promotes angiogenesis and wound healing in murine model.

Platelet-rich plasma (PRP) contains numerous growth factors to promote wound healing and angiogenesis. The objective of this study was to explore the efficacy of biodegradable gelatin hydrogel impregnated with PRP releasate (PRPr) in the wound healing process compared with the single application of PRPr prepared from mouse PRP centrifuged by a double-spin method. Gelatin hydrogel disks with an isoelectric point of 5.0 were used in this study. A total of 180 mice (n = 45/group) were randomly assigned to the following 4 experimental groups: control group, biodegradable gelatin hydrogel group, PRPr group and gelatin hydrogel impregnated with PRPr (PRPrG) group. Wound area and epithelialization were compared on days 1, 5, 7, 14 and 21 post-wounding. After complete epithelialization, wound contraction was also evaluated. Neovascularization using immunohistochemical staining of von Willebrand factor was analyzed on day 14. The wound area of PRPrG on days 5, 7 and 14 was smaller than that in the other groups (p < 0.01). The epithelialization lengths of PRPrG on days 7 and 14 were significantly longer than the others (p < 0.01). The capillary formation of PRPrG was also superior to those in all other groups on day 14. On day 21, all wounds were completely epithelialized and PRPrG prevented wound contraction the most. It is concluded that the sustained-release system of gelatin impregnated with PRPr can stimulate angiogenesis and accelerate wound healing compared with the single application of PRP.

Factors influencing tobacco use treatment patterns among Vietnamese health care providers working in community health centers.

BACKGROUND: Almost half of adult men in Viet Nam are current smokers, a smoking prevalence that is the second highest among South East Asian countries (SEAC). Although Viet Nam has a strong public health delivery system, according to the 2010 Global Adult Tobacco Survey, services to treat tobacco dependence are not readily available to smokers. The purpose of this study was to characterize current tobacco use treatment patterns among Vietnamese health care providers and factors influencing adherence to guideline recommended tobacco use screening and cessation interventions. METHODS: A cross sectional survey of 134 health care providers including physicians, nurses, midwives, physician assistants and pharmacists working in 23 community health centers in Viet Nam. RESULTS: 23% of providers reported screening patients for tobacco use, 33% offered advice to quit and less than 10% offered assistance to half or more of their patients in the past three months. Older age, attitudes, self-efficacy and normative beliefs were associated with screening for tobacco use. Normative beliefs were associated with offering advice to quit. However in the logistic regression analysis only normative beliefs remained significant for both screening and offering advice to quit. Over 90% of providers reported having never received training related to tobacco use treatment. Major barriers to treating tobacco use included lack of training, lack of referral resources and staff to support counseling, and lack of patient interest. CONCLUSIONS: Despite ratifying the FCTC, Viet Nam has not made progress in implementing policies and systems to ensure that smokers are receiving evidence-based treatment. This study suggests a need to change organizational norms through changes in national policies, training and local system-level changes that facilitate treatment.

Barriers and facilitators to expanding the role of community health workers to include smoking cessation services in Vietnam: a qualitative analysis.

BACKGROUND: Despite high smoking rates, cessation services are largely unavailable in Vietnam. This study explored attitudes and beliefs of community health workers (CHWs) towards expanding their role to include delivering tobacco use treatment (TUT), and potential barriers and facilitators associated with implementing a strategy in which health centers would refer patients to CHWs for cessation services. METHODS: We conducted four focus groups with 29 CHWs recruited from four district community health centers (CHCs) in Hanoi, Vietnam. RESULTS: Participants supported expanding their role saying that it fit well with their current responsibilities. They further endorsed the feasibility of serving as a referral resource for providers in local CHCs expressing the belief that CHWs were "more suitable than their clinical colleagues" to offer cessation assistance. The most frequently cited barrier to routinely offering cessation services was that despite enacting a National Tobacco Control Action plan, cessation is not one of the national prevention priorities. As a result, CHWs have not been "assigned" to help smokers quit by the Ministry of Health. Additional barriers included lack of training and time constraints. CONCLUSION: Focus groups suggest that implementing a systems-level intervention that allows providers to refer smokers to CHWs is a promising model for extending the treatment of tobacco use beyond primary care settings and increasing access to smoking cessation services in Vietnam. There is a need to test the cost-effectiveness of this and other strategies for implementing TUT guidelines to support and inform national tobacco control policies in Vietnam and other low-and middle-income countries.

The Chicken Egg: An Advanced Material for Tissue Engineering.

The chicken egg, an excellent natural source of proteins, has been an overlooked native biomaterial with remarkable physicochemical, structural, and biological properties. Recently, with significant advances in biomedical engineering, particularly in the development of 3D in vitro platforms, chicken egg materials have increasingly been investigated as biomaterials due to their distinct advantages such as their low cost, availability, easy handling, gelling ability, bioactivity, and provision of a developmentally stimulating environment for cells. In addition, the chicken egg and its by-products can improve tissue engraftment and stimulate angiogenesis, making it particularly attractive for wound healing and tissue engineering applications. Evidence suggests that the egg white (EW), egg yolk (EY), and eggshell membrane (ESM) are great biomaterial candidates for tissue engineering, as their protein composition resembles mammalian extracellular matrix proteins, ideal for cellular attachment, cellular differentiation, proliferation, and survivability. Moreover, eggshell (ES) is considered an excellent calcium resource for generating hydroxyapatite (HA), making it a promising biomaterial for bone regeneration. This review will provide researchers with a concise yet comprehensive understanding of the chicken egg structure, composition, and associated bioactive molecules in each component and introduce up-to-date tissue engineering applications of chicken eggs as biomaterials.

MPCNN: A Novel Matrix Profile Approach for CNN-based Single Lead Sleep Apnea in Classification Problem.

Sleep apnea (SA) is a significant respiratory condition that poses a major global health challenge. Deep Learning (DL) has emerged as an efficient tool for the classification problem in electrocardiogram (ECG)-based SA diagnoses. Despite these advancements, most common conventional feature extractions derived from ECG signals in DL, such as R-peaks and RR intervals, may fail to capture crucial information encompassed within the complete ECG segments. In this study, we propose an innovative approach to address this diagnostic gap by delving deeper into the comprehensive segments of the ECG signal. The proposed methodology draws inspiration from Matrix Profile algorithms, which generate an Euclidean distance profile from fixed-length signal subsequences. From this, we derived the Min Distance Profile (MinDP), Max Distance Profile (MaxDP), and Mean Distance Profile (MeanDP) based on the minimum, maximum, and mean of the profile distances, respectively. To validate the effectiveness of our approach, we use the modified LeNet-5 architecture as the primary CNN model, along with two existing lightweight models, BAFNet and SE-MSCNN. Our experiment results on the PhysioNet Apnea-ECG dataset (70 overnight recordings), and the UCDDB dataset (25 overnight recordings) revealed that our new feature extraction method achieved per-segment accuracies of up to 92.11% and 81.25%, respectively. Moreover, using the PhysioNet data, we achieved a per-recording accuracy of 100% and yielded the highest correlation of 0.989 compared to state-of-the-art methods. By introducing a new feature extraction method based on distance relationships, we enhanced the performance of certain lightweight models in DL, showing potential for home sleep apnea test (HSAT) and SA detection in IoT devices. The source code for this work is made publicly available in GitHub: https://github.com/vinuni-vishc/MPCNN-Sleep-Apnea.

Treating a collagen scaffold with a low concentration of nicotine promoted angiogenesis and wound healing.

BACKGROUND: Nicotine, one of the major pharmacologically active agents of cigarette smoke, has various effects on cell proliferation, and it has recently been reported to have angiogenic effects. In our previous study, we showed that the topical administration of nicotine at a low concentration accelerated wound healing. This study aimed to evaluate the efficacy of nicotine and synergistic effects of combination treatment with nicotine and basic fibroblast growth factor (bFGF) in a murine excisional wound model treated with artificial dermis. METHODS: Full-thickness defects (8 mm in diameter) were created on the backs of mice, and artificial dermis was sutured to the defects. Phosphate-buffered saline (10 µL), nicotine (10(-3), 10(-4), or 10(-5) M), bFGF (0.5 µg), and both bFGF and 10(-4) M nicotine were topically administered to the artificial dermal tissue for 7 d. The mice were killed on day 14, and the wound area, neoepithelium length, and area of newly formed capillaries in the artificial dermis were evaluated. RESULTS: The wound areas treated with 10(-4) M nicotine, bFGF, or bFGF plus 10(-4) M nicotine were significantly smaller than those in the control group. In these three groups, the neoepithelium in the bFGF plus 10(-4) M nicotine group was significantly longer than that in the other groups. There was no significant difference between the neoepithelium lengths of the control and 10(-5) M nicotine groups. The 10(-3) M nicotine group displayed the least re-epithelization among the groups. CONCLUSIONS: In this study, 10(-4) M nicotine induced angiogenesis in, and accelerated the healing of, wounds treated with artificial dermis. bFGF and nicotine had synergistic effects, and the combined use of nicotine and bFGF is an effective wound healing method.

Autologous skin reconstruction by combining epidermis and acellular dermal matrix tissue derived from the skin of giant congenital melanocytic nevi.

Giant congenital melanocytic nevi (GCMN) are defined as nevi greater than 20 cm in diameter. It is difficult to completely remove GCMN because of the lack of available skin grafts for covering the resultant defects. This study examined whether it is possible to produce reconstructed skin by combining epidermal and acellular dermal matrix (ADM) tissue derived from excised GCMN. GCMN skin samples were obtained with the informed consent of volunteer patients. The abilities of hypertonic saline (1 N NaCl), 0.05% trypsin, 0.1% SDS (sodium dodecyl sulfate), and phosphate buffered saline (PBS) to decellularize GCMN tissue were compared. The specimens were incubated in one of the test solutions at 37 °C for 48 h, before being washed with PBS at 4 °C for 14 days. Residual nuclei, residual DNA, nevus tissue viability, and the structural integrity of the basement membrane and capillaries were evaluated before treatment, and after 48 h' treatment with or without 7 or 14 days' washing. We tried to produce reconstructed skin by combining the resultant ADM with enzymatically separated GCMN epidermal tissue. The histological structure of the reconstructed skin was examined after it had been cultured for 5 days. In the SDS group, most cells had been removed after 48 h, and the DNA content of the ADM was significantly lower than in the other groups. As for viability, no significant difference was detected among the groups. The basement membrane and capillaries remained intact in all groups. After 5 days' culturing, the epidermis had become attached to the ADM in all groups, except the SDS group. SDS displayed a superior decellularization ability compared with the other methods; however, it cannot be used to produce reconstructed skin because of its toxicity. In conclusion, we produced reconstructed skin that was devoid of nevus cells by combining GCMN epidermal tissue with GCMN-derived ADM produced with NaCl or trypsin. This is a promising treatment strategy for giant nevus.

PediCXR: An open, large-scale chest radiograph dataset for interpretation of common thoracic diseases in children.

Computer-aided diagnosis systems in adult chest radiography (CXR) have recently achieved great success thanks to the availability of large-scale, annotated datasets and the advent of high-performance supervised learning algorithms. However, the development of diagnostic models for detecting and diagnosing pediatric diseases in CXR scans is undertaken due to the lack of high-quality physician-annotated datasets. To overcome this challenge, we introduce and release PediCXR, a new pediatric CXR dataset of 9,125 studies retrospectively collected from a major pediatric hospital in Vietnam between 2020 and 2021. Each scan was manually annotated by a pediatric radiologist with more than ten years of experience. The dataset was labeled for the presence of 36 critical findings and 15 diseases. In particular, each abnormal finding was identified via a rectangle bounding box on the image. To the best of our knowledge, this is the first and largest pediatric CXR dataset containing lesion-level annotations and image-level labels for the detection of multiple findings and diseases. For algorithm development, the dataset was divided into a training set of 7,728 and a test set of 1,397. To encourage new advances in pediatric CXR interpretation using data-driven approaches, we provide a detailed description of the PediCXR data sample and make the dataset publicly available on https://physionet.org/content/vindr-pcxr/1.0.0/ .