Transmission of new CRF07_BC Strains with 7 amino acid deletion in Gag p6

A 7 amino acid deletion in Gag p6 (P6delta7) emerged in Chinese prevalent HIV-1 strain CRF07_BC from different epidemic regions. It is important to determine whether this mutation could be transmitted and spread. In this study, HIV-1 Gag sequences from 5 different epidemic regions in China were collected to trace the transmission linkage and to analyze genetic evolution of P6delta7 strains. The sequence analysis demonstrated that P6delta7 is a CRF07_BC specific deletion, different P6delta7 strains could be originated from different parental CRF07_BC recombinants in different epidemic regions, and the transmission of P6delta7 strain has occurred in IDU populations. This is for the first time to identify the transmission linkage for P6delta7 strains and serves as a wake-up call for further monitoring in the future; In addition, P6delta7 deletion may represent an evolutionary feature which might exert influence on the fitness of CRF07_BC strain

Investigations on Inhibitors of Hedgehog Signal Pathway: A Quantitative Structure-Activity Relationship Study

The hedgehog signal pathway is an essential agent in developmental patterning, wherein the local concentration of the Hedgehog morphogens directs cellular differentiation and expansion. Furthermore, the Hedgehog pathway has been implicated in tumor/stromal interaction and cancer stem cell. Nowadays searching novel inhibitors for Hedgehog Signal Pathway is drawing much more attention by biological, chemical and pharmological scientists. In our study, a solid computational model is proposed which incorporates various statistical analysis methods to perform a Quantitative Structure-Activity Relationship (QSAR) study on the inhibitors of Hedgehog signaling. The whole QSAR data contain 93 cyclopamine derivatives as well as their activities against four different cell lines (NCI-H446, BxPC-3, SW1990 and NCI-H157). Our extensive testing indicated that the binary classification model is a better choice for building the QSAR model of inhibitors of Hedgehog signaling compared with other statistical methods and the corresponding in silico analysis provides three possible ways to improve the activity of inhibitors by demethylation, methylation and hydroxylation at specific positions of the compound scaffold respectively. From these, demethylation is the best choice for inhibitor structure modifications. Our investigation also revealed that NCI-H466 served as the best cell line for testing the activities of inhibitors of Hedgehog signal pathway among others

Low temperature spark plasma sintering of TC4/HA composites

Ti6Al4V/hydroxyapatite composites (TC4/HA) have been prepared by high energy ball milling and low temperature spark plasma sintering at 600 °C, 550 °C, 500 °C and 450 °C, respectively. The sintering temperature of the composites was sharply decreased as the result of the activation and surficial modification effects induced from high energy ball milling. The decomposition and reaction of hydroxyapatite was successfully avoided, which offers the composites superior biocompatibility. The hydroxyapatite in the composites was distributed in gap uniformly, and formed an ideal network structure. The lowest hardness, compressive strength and Young's modulus of the composites satisfy the requirements of human bone

Modeling and Dynamic-Simulating the Water Distribution of a Fixed Spray-Plate Sprinkler on a Lateral-Move Sprinkler Irrigation System

Uniformity of water distribution plays an important role in evaluating irrigation quality. As necessities in calculating irrigation uniformity during designing a lateral-move sprinkler irrigation system (LMSIS), the water distribution patterns of individual sprinkler in motion are crucial. Considering the limitation of the experiment platform, dynamic water distribution of an isolated sprinkler is difficult to measure, especially for a fixed spray plate sprinkler (FSPS) which LMSIS has been widely equipped with in China, therefore developing a model to simulate dynamic water distribution of a moving sprinkler is necessary. The objective of this study was to develop and validate the theoretical basis for calculating water distribution characteristics of a single FSPS in translational motion applying a superposition method, and provide an optimized operation management of LMSIS. The theoretical model’s validity was verified in an indoor experiment using a Nelson D3000 FSPS in motion with 36 grooves and blue-plate spray heads. The software was programmed using the Eclipse Platform and the software was capable of simulating water distribution pattern and Christiansen uniformity coefficient (Cu). The results indicated that the water distribution simulated by the software presents three peaks of maximum application under varying conditions, and the value of water application peaks decreased as working pressure and/or mounting height increased. Conversely, the wetted diameter increased as working pressure and/or mounting height increased. Working pressure, mounting height, and sprinkler spacing each had a significant effect on the Cu. The Cu increased as working pressure and/or mounting height increased but decreased as sprinkler spacing increased. As a consequence, the model can be used to predict the relative water distribution pattern; and the Cu can be calculated with the simulated data, thus providing a tool for designing a new LMSIS

Research on Reliability Growth of Shock Absorption System in Rapid Secure Device of Shipboard Helicopter

Aiming the problem that the mechanical claw in very few rapid secure devices (RSD) failed to capture the fixed rod of the shipboard helicopter due to the lose effectiveness of the internal shock absorption system of the RSD, a reliability growth test bench is built to conduct a reliability growth test study on the shock absorption system in a single RSD test prototype. The fault locations are identified according to the fault phenomenon. After the fault causes are found, the reliability optimization designs of the shock absorption system are carried out and the optimization design schemes are determined. With the discrete army materiel systems analysis activity (AMSAA) model analysis method, according to the reliability growth test data of the test prototype, the maximum likelihood estimation of the model parameters is determined based on a genetic algorithm. A trend test for the reliability growth of the test prototype and goodness-of-fit test for the AMSAA model are performed, and the reliability estimation and lower confidence limit of the reliability of the test prototype in the final development stage of the shock absorption system are obtained. The test data and statistical inference indicate that the reliability optimization designs using scheme 2 in the first test stage and scheme 1 + scheme 2 in the second test stage are correct and feasible, which meets the reliability requirements that the RSD reliability is not less than 99.5% and improves the robustness of the shock absorption system. This study further provides data support for the reliability research of RSD, which is of great significance for improving the service capacity of RSD equipment and ensuring the life safety of shipboard helicopters

Recent progress in low‐cost noncovalently fused‐ring electron acceptors for organic solar cells

Abstract The power conversion efficiencies (PCEs) of organic solar cells (OSCs) have improved considerably in recent years with the development of fused‐ring electron acceptors (FREAs). Currently, FREAs‐based OSCs have achieved high PCEs of over 19% in single‐junction OSCs. Whereas the relatively high synthetic complexity and the low yield of FREAs typically result in high production costs, hindering the commercial application of OSCs. In contrast, noncovalently fused‐ring electron acceptors (NFREAs) can compensate for the shortcomings of FREAs and facilitate large‐scale industrial production by virtue of the simple structure, facile synthesis, high yield, low cost, and reasonable efficiency. At present, OSCs based on NFREAs have exceeded the PCEs of 15% and are expected to reach comparable efficiency as FREAs‐based OSCs. Here, recent advances in NFREAs in this review provide insight into improving the performance of OSCs. In particular, this paper focuses on the effect of the chemical structures of NFREAs on the molecule conformation, aggregation, and packing mode. Various molecular design strategies, such as core, side‐chain, and terminal group engineering, are presented. In addition, some novel polymer acceptors based on NFREAs for all‐polymer OSCs are also introduced. In the end, the paper provides an outlook on developing efficient, stable, and low‐cost NFREAs for achieving commercial applications

Liquid–Liquid Extraction of Volatile Fatty Acids from Anaerobic Acidification Broth Using Ionic Liquids and Cosolvent

Promoting efficiency of liquid–liquid extraction at a high pH is a main challenge for the recovery of volatile fatty acids (VFAs) from organic wastes. In this study, the extraction efficiency of VFAs from artificial solution and acidification fermentation broth of kitchen wastes using ionic liquids (ILs) was assessed at high pH. The effect of ILs addition ratio in diluent, volumetric solvent to feed ratio (S/F) on extraction efficiency were investigated. The solvent consists of [P666,14][Cl] (IL101) and dodecane was found to be the promising solvent for VFA extraction at pH 6.0, especially for butyric acid. The IL-101 ratio in dodecane and S/F was significant factors for the liquid–liquid extraction of VFAs. In general, a higher IL-101 ratio and S/F can promote the extraction efficiency of single VFAs. As a result, the maximum extraction rate of acetic acid (38.4–49.9%) and butyric acid (66.0–92.1%) from different VFA concentration solutions was observed at 10% IL-101 in dodecane and S/F = 2/1. The solvent was also effective in different types of real fermentation broth of kitchen wastes. The maximum extraction rate and selectivity of butyric acid was 60.2%/70.5% in butyric acid type broth and 74.6%/62.7% in mixture acid type broth

Development of sedimentary geology of petroliferous basins in China

This paper gives a contrastive analysis of the main progress made in petroliferous basins sedimentary geology domestically and internationally, and discusses the main problems and their solutions in the development of petroliferous basins sedimentology in China, New developments include coarse-grained depositional sysytem, shallow-water deltic depositional system, beach bar depositional system, deep-water gravity flows, fine-grained depositional system, carbonate reefs, mixosedimentite, microbialite, seismic sedimentology and sedimentary physical simulation. It also reveals the developing gap of Chinese sedimentology in the areas of microbialite and sedimentary simulation, etc. and analyzes the sedimentary features and paleogeography pattern of prototype basins, multi-scale paleogeographic recovery during major tectonic movements, the different explanation of new sedimentology theories in the deep-buried sandbodies development. The paper details the difficulties when it comes to the typical depositional systems combination and the setup of sedimentary models in China. Therefore, the developing tendency is described of sedimentology theories like source to sink, sedimentary dynamics as well as regional sedimentology in China, seismic sedimentology, and studying methods and technologies in sedimentary simulation. Key words: development, shallow-water delta, gravity flow, beach-bar, mixosedimentite, microbialite, seismic sedimentology, sedimentology, Chin