艾比湖区域景观格局空间特征与地表水质的关联分析

为进一步明确区域土地利用/覆被—景观格局对河流水质影响的空间尺度。选择新疆艾比湖区域为研究对象,以25个水质采样点为中心,建立5种尺度的河流缓冲区并提取不同尺度下的土地利用/覆被-景观格局数据。首先,通过主成分分析获得水环境的主要水质变量。其次,利用冗余分析(RDA)方法探讨研究区不同宽度缓冲区土地利用/覆被—景观格局对河流水质的影响,获得水质管理的有效缓冲区。最后,引入突变点分析方法进一步寻找导致水质变量沿景观梯度突变的特定位置。结果表明:(1)土地利用/覆被—景观格局在不同宽度缓冲区内对河流水质的影响不同。4 km缓冲区土地利用/覆被—景观格局对区域水质有较强的分异解释能力,因此4 km缓冲区的景观格局合理配置对河流水质管理尤为重要。(2)通过偏RDA分析发现4 km缓冲区中,影响区域水质的主要环境变量为景观水平斑块密度、类型水平耕地斑块密度和森林聚集度。(3)在偏RDA分析的基础上,对4 km缓冲区内的景观指数进行突变点分析研究,发现区域景观水平斑块密度为90—105 m/hm~2,类型水平耕地的斑块密度ED值在90—110 m/hm~2、林草地的AI值在70%—90%,是艾比湖区域水质保护的最佳突变值,该值为艾比湖区域水质保护的阈值。本研究从多个角度对新疆艾比区域的土地利用/覆被—景观格局对区域水质的影响进行定量分析,揭示该地区景观生态变化的规律,为区域景观格局优化和土地合理规划提供理论依据,并对改善"丝绸之路经济带"生态环境、实现资源可持续利用具有重要的现实意义和理论价值。     

The Drosophila homologue of Arf-GAP GIT1, dGIT, is required for proper muscle morphogenesis and guidance during embryogenesis

GIT1-like proteins are GTPase-activating proteins (GAPs) for Arfs and interact with a variety of signaling molecules to function as integrators of pathways controlling cytoskeletal organization and cell motility. In this report, we describe the characterization of a Drosophila homologue of GIT1, dGIT, and show that it is required for proper muscle morphogenesis and myotube guidance in the fly embryo. The dGIT protein is concentrated at the termini of growing myotubes and localizes to muscle attachment sites in late stage embryos. dgit mutant embryos show muscle patterning defects and aberrant targeting in subsets of their muscles. dgit mutant muscles fail to localize the p21-activated kinase, dPak, to their termini. dPak and dGIT form a complex in the presence of dPIX and dpak mutant embryos show similar muscle morphogenesis and targeting phenotypes to that of dgit. We propose that dGIT and dPak are part of a complex that promotes proper muscle morphogenesis and myotube targeting during embryogenesis.     

种植盐地碱蓬改良滨海盐渍土对土壤微生物区系的影响

利用盐生植物盐地碱蓬对天津河口滨海盐碱地进行生物修复,研究了其对土壤微生物区系的影响.结果表明,种植区碱蓬根系土壤的可溶性盐分与对照土壤相比下降了41%（重量法）和37%（电导法）;根系土壤的微生物数量明显增加,其中细菌、放线菌和真菌分别较对照增加了2.3倍、4.3倍和71倍,与对照相比均为显著性差异.根系微生物的耐盐性结果显示,随着土壤盐分的降低,根系微生物生长的最适盐度也随之降低,耐盐性较低的微生物种群已逐渐成为优势种群.系统发育分析表明,枯草杆菌属成为植物修复后土壤中的优势种群.     

Intervention Strategies for Improving Patient Adherence to Follow-Up in the Era of Mobile Information Technology: A Systematic Review and Meta-Analysis

Background

Patient adherence to follow-up plays a key role in the medical surveillance of chronic diseases and affects the implementation of clinical research by influencing cost and validity. We previously reported a randomized controlled trial (RCT) on short message service (SMS) reminders, which significantly improved follow-up adherence in pediatric cataract treatment.

Methods

RCTs published in English that reported the impact of SMS or telephone reminders on increasing or decreasing the follow-up rate (FUR) were selected from Medline, EMBASE, PubMed, and the Cochrane Library through February 2014. The impacts of SMS and telephone reminders on the FUR of patients were systematically evaluated by meta-analysis and bias was assessed.

Results

We identified 13 RCTs reporting on 3276 patients with and 3402 patients without SMS reminders and 8 RCTs reporting on 2666 patients with and 3439 patients without telephone reminders. For the SMS reminders, the majority of the studies (>50%) were at low risk of bias, considering adequate sequence generation, allocation concealment, blinding, evaluation of incomplete outcome data, and lack of selective reporting. For the studies on the telephone reminders, only the evaluation of incomplete outcome data accounted for more than 50% of studies being at low risk of bias. The pooled odds ratio (OR) for the improvement of follow-up adherence in the SMS group compared with the control group was 1.76 (95% CI [1.37, 2.26]; P<0.01), and the pooled OR for the improvement of follow-up adherence in the telephone group compared with the control group was 2.09 (95% CI [1.85, 2.36]; P<0.01); both sets showed no evidence of publication bias.

Conclusions

SMS and telephone reminders could both significantly improve the FUR. Telephone reminders were more effective but had a higher risk of bias than SMS reminders.     

Aqueous‐Processed Polymer/Nanocrystal Hybrid Solar Cells with Double‐Side Bulk Heterojunction

Aqueous‐solution‐processed solar cells (ASCs) are promising candidates of the next‐generation large‐area, low‐cost, and flexible photovoltaic conversion equipment because of their unique environmental friendly property. Aqueous‐solution‐processed polymer/nanocrystals (NCs) hybrid solar cells (AHSCs) can effectively integrate the advantages of the polymer (e.g., flexibility and lightweight) and the inorganic NCs (e.g., high mobility and broad absorption), and therefore be considered as an ideal system to further improve the performance of ASCs. In this work, double‐side bulk heterojunction (BHJ), in which one BHJ combines the active material with electron transport material and the other combines the active material with hole transport material, is developed in the AHSCs. Through comparing with the single‐side BHJ device, promoted carrier extraction, enhanced internal quantum efficiency, extended width of the depletion region, and prolonged carrier lifetime are achieved in double‐side BHJ devices. As a result, power conversion efficiency exceeding 6% is obtained, which breaks the bottleneck efficiency around ≈5.5%. This work demonstrates a device architecture which is more remarkable compared with the traditional only donor–acceptor blended BHJ. Under conservative estimation, it provides instructive architecture not only in the ASCs, but also in the organic solar cells (SCs), quantum dot SCs, and perovskite SCs.     

The impact of operations redesign on the safety stock investment in supply chains

This study is motivated by a real problem encountered in the manufacturing and distribution process at a local electronic manufacturer of security devices. We investigate the impact of operations redesign (i.e., operations merging) on the cost of safety stock in a supply chain. A simple safety stock method is used to derive a model for estimating safety stock levels. Our result shows that operations redesign can have a significant impact on safety stock investment. We extend and complement the existing literature in the following aspects: (i) we address the issue of safety stock deployment, i.e., we not only investigate the problem of how many operations should be delayed, but also determine which operations need to be delayed, (ii) we provide an efficient heuristic algorithm to determine which operations need to be merged, and (iii) we find the optimal operations redesign strategies under some special cases. Our analysis also reveals some important conditions and insights for better operations redesign, which enable us not only to decide when an operations redesign is appropriate, but also to suggest the scale and the format of the operations redesign.     

Crystal Structure of the C-Terminal Cytoplasmic Domain of Non-Structural Protein 4 from Mouse Hepatitis Virus A59

Background

The replication of coronaviruses takes place on cytoplasmic double membrane vesicles (DMVs) originating in the endoplasmic reticulum (ER). Three trans-membrane non-structural proteins, nsp3, nsp4 and nsp6, are understood to be membrane anchors of the coronavirus replication complex. Nsp4 is localized to the ER membrane when expressed alone but is recruited into the replication complex in infected cells. It is revealed to contain four trans-membrane regions and its N- and C-termini are exposed to the cytosol.

Methodology/Principal Findings

We have determined the crystal structures of the C-terminal hydrophilic domain of nsp4 (nsp4C) from MHV strain A59 and a C425S site-directed mutant. The highly conserved 89 amino acid region from T408 to Q496 is shown to possess a new fold. The wild-type (WT) structure features two monomers linked by a Cys425-Cys425 disulfide bond in one asymmetric unit. The monomers are arranged with their N- and C-termini in opposite orientations to form an “open” conformation. Mutation of Cys425 to Ser did not affect the monomer structure, although the mutant dimer adopts strikingly different conformations by crystal packing, with the cross-linked C-termini and parallel N-termini of two monomers forming a “closed” conformation. The WT nsp4C exists as a dimer in solution and can dissociate easily into monomers in a reducing environment.

Conclusions/Significance

As nsp4C is exposed in the reducing cytosol, the monomer of nsp4C should be physiological. This structure may serve as a basis for further functional studies of nsp4.     

High-quality RNA preparation for cDNA library construction of the Antarctic sea–ice alga <Emphasis Type="Italic">Chlamydomonas</Emphasis> sp. ICE-L

To study the molecular mechanism of the Antarctic sea–ice alga in adaptation to polar sea–ice environments, the RNA was prepared for cDNA library construction of Chlamydomonas sp. ICE-L. Three different methods were tested to prepare total RNA from this psychrophilic, unicellular green alga rich in protein and polysaccharide. Lauryl sodium sulfate- based method allowed a most effective extraction of high-quality total RNA compared to the other methods. Total RNA extracted with this protocol was used for cDNA library construction. The recombination rate of constructed cDNA library was 98.60%, the primary titer was 7.15 × 10⁶ pfu, and an average sequence length was 1.2 kb. These results show that with a high-quality RNA preparation, a cDNA library can be constructed successfully for Chlamydomonas sp. ICE-L.