Effect of Polymer–Fullerene Interaction on the Dielectric Properties of the Blend

It is commonly believed that large dielectric constants are required for efficient charge separation in polymer photovoltaic devices. However, many polymers used in high‐performance solar cells do not possess high dielectric constants. In this work, the effect of polymer–fullerene interactions on the dielectric environment of the active layer blend and the device performance for several donor–acceptor conjugated polymer systems is investigated. It is found that, while none of the high‐performing polymers studied has a dielectric constant value larger than 3, all polymer–fullerene blends have a significantly larger dielectric constant compared to their pristine constituents. Additionally, it is found that the blend dielectric constant reaches a maximum value in fully optimized devices. Using PTB7:PC₇₁BM blends as an example, it is showed that, in addition to a small increase in the dielectric constant, devices fabricated using the optimum processing additive concentration exhibit almost 3X larger excited state polarizability. This large increase in excited state polarizability results in a substantial difference in short‐circuit current and ultimately device performance. The results show that the excited state polarizability critically depends on polymer–fullerene interactions, and can be a leading indicator of device performance for a given material system.     

台湾海峡浮游翼足类群聚之季节动态

本研究利用水产试验所研究船“水试一号”于2006年冬(1月)夏(7月)两季在台湾海峡海域进行水文探测及浮游动物采样, 以探讨浮游翼足类群聚组成与丰度之时空分布及其与水文环境的相关性。结果发现浮游翼足类夏季的丰度及多样性指数明显较冬季高, 而种类数则差异不大; 两季间优势种类组成相似但优势排名略有不同, 夏季主要优势种为棒笔帽螺(Creseis clava)、尖笔帽螺(C. acicula)和马蹄螔螺(Limacina trochiformis), 合占所有翼足类丰度的97%, 其中仅棒笔帽螺就占了总丰度的62%; 冬季主要优势种为胖螔螺(Limacina inflata), 占翼足类丰度的72%。翼足类丰度在空间上的分布亦有明显的季节差异, 夏季时以台湾海峡北部较高, 冬季则以南部较高。种类数与物种多样性指数则均以海峡南部较高。由水文站群分析及各站群生物及水文特征结果显示, 台湾海峡季节性水团的消长与翼足类群聚分布有十分密切的关联。     

Assessment of Phytotoxicity of Chromium in Flooded Soils using Embedded Selective Ion Exchange Resin Method

Chromium present in the forms of Cr(VI) or Cr(III) in soils. Since the toxicity and mobility of Cr(VI) are higher than those of Cr(III), it would be important to estimate soil Cr(VI) accurately in order to assess the phytotoxicity of Cr. Soil redox potential can influence the distribution of Cr between Cr(VI) and Cr(III) forms, and thus an in situ method which is not affected by the soil redox condition is needed for determining Cr(VI) availability in paddy fields. In this study, the Cu-saturated selective ion exchange resin (DOWEX M4159), serving as an infinite sink, was embedded in soils to extract available Cr(VI) from three representative saturated soils with different amounts of Cr(VI). The results suggested that Cr(VI) reduction occurred in the flooded soils, and the acid environment favored the adsorption and reduction of Cr(VI). There was a significant dose-response relationship between the soil resin-extractable Cr(VI) and the plant height of rice seedlings for test soils. The experimental results suggested that the embedded selective ion exchange resin method could be a suitable in situ method for assessing the phytotoxicity of Cr in flooded soils.     

Summer immune depression associated with increased susceptibility of the European abalone, Haliotis tuberculata to Vibrio harveyi infection

Haliotis tuberculata mortality outbreaks have occurred in France since 1998 and were attributed to a pathogenic Vibrio harveyi. These mortalities were recorded in September, a month with abalone reproduction and characterised by high seawater temperatures. The importance of gonadal maturation and temperature increase on abalone immunity and susceptibility to V. harveyi infection needed to be clarified. Therefore, an immune survey analyzing a large panel of parameters was performed from June to September 2007 on abalone from the Bay of Brest. The data obtained were put in relation with abalone reproductive status and its susceptibility to V. harveyi. Most parameters showed clear patterns from early to late summer and during gametogenesis, phagocytosis and phenoloxidase activity were reduced, whereas basal reactive oxygen species production and agglutination titres were significantly increased. Total haemocyte counts went up after the partial spawning event at the end of June, and cell complexity diminished. Using a Principal Component Analysis, the "haemolymph profile" was shown to decrease in parallel with spawning and gonadal maturation processes, and reached a minimum just after total spawning. A significant correlation between this "haemolymph profile" and disease susceptibility allowed us to establish for the first time in abalone, a clear concordance between maturation and spawning processes, immune status and abalone susceptibility to V. harveyi.     

The book reopened on infectious diseases

Emerging infectious diseases represent a major challenge to human health worldwide. The risk of evolving new infectious pathogens has been intensifying due to urbanization, demographic changes, air travel, inappropriate use of antibiotics, and climate change. These pathogens can affect humans from urban centers to the remotest corners of the globe. Far from being a scourge of the past, infectious diseases are relevant for the world today.     

Deleted in liver cancer-1 (DLC-1): a tumor suppressor not just for liver

Deleted in liver cancer 1 (DLC-1), as its name implied, was originally isolated as a potential tumor suppressor gene often deleted in hepatocellular carcinoma. Further studies have indicated that down-expression of DLC-1 either by genomic deletion or DNA methylation is associated with a variety of cancer types including lung, breast, prostate, kidney, colon, uterus, ovary, and stomach. Re-expression of DLC-1 in cancer cells regulates the structure of actin cytoskeleton and focal adhesions and significantly inhibits cell growth, supporting its role as a tumor suppressor. This tumor suppressive function relies on DLC-1's RhoGTPase activating protein (RhoGAP) activity and steroidogenic acute regulatory (StAR)-related lipid transfer (START) domain, as well as its focal adhesion localization, which is recruited by the Src Homology 2 (SH2) domains of tensins in a phosphotyrosine-independent fashion. Therefore, the expression and subcellular localization of DLC-1 could be a useful molecular marker for cancer prognosis, whereas DLC-1 and its downstream signaling molecules might be therapeutic targets for the treatment of cancer.