Histological and Biomechanical Evaluation of the Preserved Degenerative Dermis in Rat Autologous Skin Transplant Models after a Deep Second Degree Burn

To describe the histological and biomechanical changes of the preserved degenerative dermis in rat  autologous skin transplant models after a deep second-degree burn. 50 SD rats were divided into 5 groups  randomly of 10 rats of each: 7-days group, 9-days group, 14-days group, 21-days group, and 60-days group.  Deep second-degree burn wounds were prepared on the back of rats sized 3.5cm×3.5cm. Super tangential  excision was performed on the burn wound to preserve the degenerative dermis. Then, autologous epidermis  was grafted on the wound. After that, the histological changes of the preserved degenerative dermis tissues  and the graft areas were observed by macroscopic, light microscope and electron microscope in the 7, 9, 14,  21, 60 days after the operation. Moreover, the tensile properties of healing deeply burned rat skin were also  tested for each group at the same time points mentioned above. Results: (1) According to the macroscopic  observation, 7 days after the operation, the grafted skin was fused with the area of burn wound; A few hairs  were growing out on the skin at the 14th day; the injured skin recovered to normality by the 60th day. (2)  Hyaline change occurred in the preserved degenerative dermis tissues based on the observation by light  microscope. At the 7th day after operation, the dermis papillae and reticular layer could be discerned; by  the 21st day, the thickness, structures and morphology of grafted skin were similar to the normal tissues. (3)  7 days after operation, ballooning changes were observed by the electron microscope in the mitochondria  and endoplasmic reticulum of damaged cells and the number of the ribosomes was obviously reduced. The  subcellular wound improved continuously and approached normality by the 21st day. (4) 9 days after the  operation, the tensible strength and maximal strain of the grafting rat skin approached 70% and 90% of  natural skin, respectively. (5) 60 days after the operation, the tensile performance of the healing rat skin  recovered to the natural level. Conclusion: The histological and biomechanical changes of the denatured dermis of a deep second  degree burn wound may gradually recover to normality after being covered by autologous skin.

Near-atomic cryo-electron microscopy structures of varicella-zoster virus capsids

VZV是一种广泛存在并且具有高度传染性的人类α-疱疹病毒。初次感染VZV可导致水痘，人群普遍易感（感染率约为61%～100%）。该病毒可在背根神经节潜伏感染，持续终生。夏宁邵教授团队长期开展VZV相关基础与新型疫苗研究，通过系统和精细探索建立了高效的VZV规模化培养和病毒颗粒纯化技术体系，成功获得高质量的VZV颗粒样品。首次揭示了疱疹病毒α家族的水痘-带状疱疹病毒（VZV）不同类型核衣壳的近原子分辨率结构，阐明了VZV核衣壳不同组成蛋白的相互作用网络与衣壳装配机制，可为进一步开展新型载体疫苗设计及抗病毒药物等研究提供重要支持。 我校博士后王玮、高级工程师郑清炳、博士生潘德全和俞海副教授为该论文共同第一作者，我校夏宁邵教授、程通副教授、李少伟教授以及美国罗格斯大学朱桦（Hua Zhu）教授、加利福尼亚大学洛杉矶分校周正洪（Z. Hong Zhou）教授为该论文的共同通讯作者。【Abstract】Varicella-zoster virus (VZV) is a medically important human herpesvirus that causes chickenpox and shingles, but its cell-associated nature has hindered structure studies. Here we report the cryo-electron microscopy structures of purified VZV A-capsid and C-capsid, as well as of the DNA-containing capsid inside the virion. Atomic models derived from these structures show that, despite enclosing a genome that is substantially smaller than those of other human herpesviruses, VZV has a similarly sized capsid, consisting of 955 major capsid protein (MCP), 900 small capsid protein (SCP), 640 triplex dimer (Tri2) and 320 triplex monomer (Tri1) subunits. The VZV capsid has high thermal stability, although with relatively fewer intra- and inter-capsid protein interactions and less stably associated tegument proteins compared with other human herpesviruses. Analysis with antibodies targeting the N and C termini of the VZV SCP indicates that the hexon-capping SCP—the largest among human herpesviruses—uses its N-terminal half to bridge hexon MCP subunits and possesses a C-terminal flexible half emanating from the inner rim of the upper hexon channel into the tegument layer. Correlation of these structural features and functional observations provide insights into VZV assembly and pathogenesis and should help efforts to engineer gene delivery and anticancer vectors based on the currently available VZV vaccine.This research was supported by grants from the National Science and Technology Major Projects for Major New Drugs Innovation and Development (no. 2018ZX09711003-005-003), the National Science and Technology Major Project of Infectious Diseases (no. 2017ZX10304402), the National Natural Science Foundation of China (no. 81871648, 81601762), the Research Unit of Frontier Technology of Structural Vaccinology of Chinese Academy of Medical Sciences (no. 2019RU022) and the US National Institutes of Health (DE025567/028583). 该研究获得了国家自然科学基金、新药创制国家科技重大专项和传染病防治国家科技重大专项等资助

Data Caching Optimization in the Edge Computing Environment

With the rapid increase in the use of mobile devices in people’s daily lives, mobile data traffic is exploding in recent years. In the edge computing environment where edge servers are deployed in close proximity to mobile users, caching popular data on edge servers can ensure mobile users’ low-latency access to those data and reduce the data traffic between mobile users and the centralized cloud. Existing studies consider the data caching problem with a focus on the reduction of network delay and the improvement of mobile devices’ energy efficiency. In this article, we tackle this data caching problem in the edge computing environment from a service provider’s perspective with the aim to maximize its data caching revenue. This problem is challenging because there is a trade-off between the benefit produced and the cost incurred by caching data on edge servers. In the meantime, the constraint for data access latency must also be fulfilled. In this article, we formulate the data caching problem in the edge computing environment as an integer programming (IP) problem and prove its NP-completeness. To solve this problem effectively and efficiently in large-scale scenarios, we propose an approximation approach to find near-optimal solutions. Extensive experiments are conducted on a widely-used real-world dataset to evaluate our approaches

Rapid and Simple Detection of Trichosporon asahii by Optimized Colony PCR

Trichosporon asahii is the major pathogen causing invasive trichosporonosis. Conventional methods of its detection are time-consuming or costly and often require complex DNA extraction and purification steps, which hinders rapid clinical diagnosis. In this study, we evaluated colony PCR, which directly uses colonies or trace clinical samples as the template for amplification, for rapid detection of T. asahii infection. Four methods, namely, direct colony, freeze-thaw, glass beads, and enzymolysis, were compared to select the best DNA extraction strategy. We subsequently designed and screened species-specific primers targeting the intergenic spacer 1 (IGS1) of the ribosomal DNA of T. asahii and used them to detect mock infection clinical samples. The species-specific colony PCR based on glass beads proved advantageous, with short procedure time (154.8 ± 0.6 min), good sensitivity (detection limit, 102 CFU/mL), and specificity for T. asahii, indicating that this method can be used for the rapid and simple identification of clinical samples of T. asahii infection

MyoD Is a Novel Activator of Porcine FIT1 Gene by Interacting with the Canonical E-Box Element during Myogenesis

Fat-induced transcript 1 (FIT1/FITM1) gene is a member of the conserved gene family important for triglyceride-rich lipid droplet accumulation. FIT1 gene displays a similar muscle-specific expression across pigs, mice, and humans. Thus pigs can act as a useful model of many human diseases resulting from misexpression of FIT1 gene. Triglyceride content in skeletal muscle plays a key role in pork meat quality and flavors. An insertion/deletion mutation in porcine FIT1 coding region shows a high correlation with a series of fat traits. To gain better knowledge of the potential role of FIT1 gene in human diseases and the correlations with pork meat quality, our attention is given to the region upstream of the porcine FIT1 coding sequence. We cloned ~1 kb of the 5′-flanking region of porcine FIT1 gene to define the role of this sequence in modulating the myogenic expression. A canonical E-box element that activated porcine FIT1 promoter activity during myogenesis was identified. Further analysis demonstrated that promoter activity was induced by overexpression of MyoD1, which bound to this canonical E-box during C2C12 differentiation. This is the first evidence that FIT1 as the direct novel target of MyoD is involved in muscle development

Highly water-soluble, porous, and biocompatible boron nitrides for anticancer drug delivery

Developing materials for "Nano-vehicles" with clinically approved drugs encapsulated is envisaged to enhance drug therapeutic effects and reduce the adverse effects. However, design and preparation of the biomaterials that are porous, nontoxic, soluble, and stable in physiological solutions and could be easily functionalized for effective drug deliveries are still challenging. Here, we report an original and simple thermal substitution method to fabricate perfectly water-soluble and porous boron nitride (BN) materials featuring unprecedentedly high hydroxylation degrees. These hydroxylated BNs are biocompatible and can effectively load anticancer drugs (e.g., doxorubicin, DOX) up to contents three times exceeding their own weight. The same or even fewer drugs that are loaded on such BN carriers exhibit much higher potency for reducing the viability of LNCaP cancer cells than free drugs