Scaling law of deep-sea trinitrotoluene (TNT) explosion

Understanding the dynamic characteristics of deep-sea explosions is essential to improve the survivability and combat capability of deep-sea equipment. In this paper, by considering the practical underwater conditions, we investigated the mechanical effects of the deep-sea 1-kg-trinitrotoluene (TNT) explosion with charge depths ranging from 1 to 10 km through numerical simulation and dimensional analysis. The shock wave overpressure, the positive overpressure pulse, the bubble pulse, and the energy distribution for various depth explosions were analyzed systematically. The simulation results showed that the charge depth was negligible for the peak overpressure of the shock wave. However, the positive overpressure pulse, the shock wave energy, the maximum bubble radius, the bubble energy, and the bubble period decrease significantly with increasing the charge depth. Then, the dimensional analysis for deep-sea TNT explosion was performed to reveal the key dimensionless parameters, from which the scaling laws of the shock wave overpressure and the overpressure pulse were obtained. By fitting the simulation results, the dimensionless equations were proposed, providing an effective method for predicting the peak overpressure and the positive overpressure pulse of shock wave for underwater TNT explosion over a wide range of water depths

Anomalous Elastic Properties of Attraction-Dominated DNA Self-Assembled 2D Films and the Resultant Dynamic Biodetection Signals of Microbeam Sensors

The condensation of DNA helices has been regularly found in cell nucleus, bacterial nucleoids, and viral capsids, and during its relevant biodetections the attractive interactions between DNA helices could not be neglected. In this letter, we theoretically characterize the elastic properties of double-stranded DNA (dsDNA) self-assembled 2D films and their multiscale correlations with the dynamic detection signals of DNA-microbeams. The comparison of attraction- and repulsion-dominated DNA films shows that the competition between attractive and repulsive micro-interactions endows dsDNA films in multivalent salt solutions with anomalous elastic properties such as tensile surface stresses and negative moduli; the occurrence of the tensile surface stress for the attraction-dominated DNA self-assembled film reveals the possible physical mechanism of the condensation found in organism. Furthermore, dynamic analyses of a hinged–hinged DNA-microbeam reveal non-monotonous frequency shifts due to attraction- or repulsion-dominated dsDNA adsorptions and dynamic instability occurrence during the detections of repulsion-dominated DNA films. This dynamic instability implies the existence of a sensitive interval of material parameters in which DNA adsorptions will induce a drastic natural frequency shift or a jump of vibration mode even with a tiny variation of the detection conditions. These new insights might provide us some potential guidance to achieve an ultra-highly sensitive biodetection method in the future

Blood‐derived product therapies for SARS‐CoV‐2 infection and long COVID

Abstract Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is capable of large‐scale transmission and has caused the coronavirus disease 2019 (COVID‐19) pandemic. Patients with COVID‐19 may experience persistent long‐term health issues, known as long COVID. Both acute SARS‐CoV‐2 infection and long COVID have resulted in persistent negative impacts on global public health. The effective application and development of blood‐derived products are important strategies to combat the serious damage caused by COVID‐19. Since the emergence of COVID‐19, various blood‐derived products that target or do not target SARS‐CoV‐2 have been investigated for therapeutic applications. SARS‐CoV‐2‐targeting blood‐derived products, including COVID‐19 convalescent plasma, COVID‐19 hyperimmune globulin, and recombinant anti‐SARS‐CoV‐2 neutralizing immunoglobulin G, are virus‐targeting and can provide immediate control of viral infection in the short term. Non‐SARS‐CoV‐2‐targeting blood‐derived products, including intravenous immunoglobulin and human serum albumin exhibit anti‐inflammatory, immunomodulatory, antioxidant, and anticoagulatory properties. Rational use of these products can be beneficial to patients with SARS‐CoV‐2 infection or long COVID. With evidence accumulated since the pandemic began, we here summarize the progress of blood‐derived product therapies for COVID‐19, discuss the effective methods and scenarios regarding these therapies, and provide guidance and suggestions for clinical treatment

Biodistribution of 60Co–Co/Graphitic-Shell Nanocrystals In Vivo

The magnetic nano-materials, Co/graphitic carbon- (GC-) shell nanocrystals, were made via chemicalvapour deposition (CVD) method, and their biodistribution and excretion in mice were studied by using postintravenously (i.v.) injecting with 60Co–Co/GC nanocrystals. The results showed that about 5% of Co was embedded into graphitic carbon to form multilayer Co/GC nanocrystals and the size of the particle was ~20 nm, the thickness of the nanocrystal cover layer was ~4 nm, and the core size of Co was ~14 nm. Most of the nanocrystals were accumulated in lung, liver, and spleen after 6, 12, 18, and 24 h after i.v. with 60Co–Co/GC nanocrystals. The nanoparticles were cleared rapidly from blood and closed to lower level in 10 min after injection. The 60Co–Co/GC nanocrystals were eliminated slowly from body in 24 h after injection, ~6.09% of 60Co–Co/GC nanocrystals were excreted by urine, ~1.85% by feces in 24 h, and the total excretion was less than 10%

Fast SAR Image Change Detection Using Bayesian Approach Based Difference Image and Modified Statistical Region Merging

A novel fast SAR image change detection method is presented in this paper. Based on a Bayesian approach, the prior information that speckles follow the Nakagami distribution is incorporated into the difference image (DI) generation process. The new DI performs much better than the familiar log ratio (LR) DI as well as the cumulant based Kullback-Leibler divergence (CKLD) DI. The statistical region merging (SRM) approach is first introduced to change detection context. A new clustering procedure with the region variance as the statistical inference variable is exhibited to tailor SAR image change detection purposes, with only two classes in the final map, the unchanged and changed classes. The most prominent advantages of the proposed modified SRM (MSRM) method are the ability to cope with noise corruption and the quick implementation. Experimental results show that the proposed method is superior in both the change detection accuracy and the operation efficiency

Unsupervised Change Detection for VHR Remote Sensing Images Based on Temporal-Spatial-Structural Graphs

With the aim of automatically extracting fine change information from ground objects, change detection (CD) for very high resolution (VHR) remote sensing images is extremely essential in various applications. However, the increase in spatial resolution, more complicated interactive relationships of ground objects, more evident diversity of spectra, and more severe speckle noise make accurately identifying relevant changes more challenging. To address these issues, an unsupervised temporal-spatial-structural graph is proposed for CD tasks. Treating each superpixel as a node of graph, the structural information of ground objects presented by the parent–offspring relationships with coarse and fine segmented scales is introduced to define the temporal-structural neighborhood, which is then incorporated with the spatial neighborhood to form the temporal-spatial-structural neighborhood. The graphs defined on such neighborhoods extend the interactive range among nodes from two dimensions to three dimensions, which can more perfectly exploit the structural and contextual information of bi-temporal images. Subsequently, a metric function is designed according to the spectral and structural similarity between graphs to measure the level of changes, which is more reasonable due to the comprehensive utilization of temporal-spatial-structural information. The experimental results on both VHR optical and SAR images demonstrate the superiority and effectiveness of the proposed method

Genome-Wide Identification, Expression, and Functional Analysis of the Sugar Transporter Gene Family in Cassava (Manihot esculenta)

The sugar transporter (STP) gene family encodes monosaccharide transporters that contain 12 transmembrane domains and belong to the major facilitator superfamily. STP genes play critical roles in monosaccharide distribution and participate in diverse plant metabolic processes. To investigate the potential roles of STPs in cassava (Manihot esculenta) tuber root growth, genome-wide identification and expression and functional analyses of the STP gene family were performed in this study. A total of 20 MeSTP genes (MeSTP1–20) containing the Sugar_tr conserved motifs were identified from the cassava genome, which could be further classified into four distinct groups in the phylogenetic tree. The expression profiles of the MeSTP genes explored using RNA-seq data showed that most of the MeSTP genes exhibited tissue-specific expression, and 15 out of 20 MeSTP genes were mainly expressed in the early storage root of cassava. qRT-PCR analysis further confirmed that most of the MeSTPs displayed higher expression in roots after 30 and 40 days of growth, suggesting that these genes may be involved in the early growth of tuber roots. Although all the MeSTP proteins exhibited plasma membrane localization, variations in monosaccharide transport activity were found through a complementation analysis in a yeast (Saccharomyces cerevisiae) mutant, defective in monosaccharide uptake. Among them, MeSTP2, MeSTP15, and MeSTP19 were able to efficiently complement the uptake of five monosaccharides in the yeast mutant, while MeSTP3 and MeSTP16 only grew on medium containing galactose, suggesting that these two MeSTP proteins are transporters specific for galactose. This study provides significant insights into the potential functions of MeSTPs in early tuber root growth, which possibly involves the regulation of monosaccharide distribution