Replication and protection of telomeres

During the evolution of linear genomes, it became essential to protect the natural chromosome ends to prevent triggering of the DNA-damage repair machinery and enzymatic attack. Telomeres - tightly regulated complexes consisting of repetitive G-rich DNA and specialized proteins - accomplish this task. Telomeres not only conceal linear chromosome ends from detection and inappropriate repair but also provide a buffer to counteract replication-associated shortening. Lessons from many model organisms have taught us about the complications of maintaining these specialized structures. Here, we discuss how telomeres interact and cooperate with the DNA replication and DNA-damage repair machineries.     

Germline mutations in PRKCSH are associated with autosomal dominant polycystic liver disease

Polycystic liver disease (PCLD, OMIM 174050) is a dominantly inherited condition characterized by the presence of multiple liver cysts of biliary epithelial origin. Fine mapping established linkage to marker D19S581 (Z(max) = 9.65; theta = 0.01) in four large Dutch families with PCLD. We identified a splice-acceptor site mutation (1138-2A-->G) in PRKCSH in three families, and a splice-donor site mutation (292+1G-->C) in PRKCSH segregated completely with PCLD in another family. The protein encoded by PRKCSH, here named hepatocystin, is predicted to localize to the endoplasmic reticulum. These findings establish germline mutations in PRKCSH as the probable cause of PCLD.     

用于数据库新兴应用程序的逻辑

逻辑与数据库及信息系统之间的关系是广泛和长期存在的。对于数据库理论家而言，逻辑是一个统一的框架。在该框架内可以理解数据模型和查询语言的语义学；允许对它们的可表达性进行比较；并且应用高度开发的数学逻辑工具给出深入的理解。随着数据库系统管理的信息类型日益丰富．数据库和信息系统的逻辑价值也就更加突出。异构和分布式数据源包括了从遗传序列到具有丰富时态的结构；从结合文本与数据的半结构文件到有关复杂组织协同进程的信息。     

用于交通标志检测的窗口大小聚类残差SSD模型

SSD通常被认为适合于求解小目标图像检测问题,但在特征表征和检测效率两方面还存在改进空间.提出一种聚类残差SSD模型,一方面将原始SSD模型中的VGG16基础网络替换为更深的ResNet50残差网络,以改善特征表征能力.另一方面采用K-均值聚类算法取代盲目搜索机制,确定SSD中默认窗口的大小,以改善检测效率.针对德国交通标志检测数据集,模型获得了97.1%mAP和每幅图像0.07 s的检测速度.针对中国交通标志数据集,模型获得89.7%mAP和每幅图像0.08 s的检测速度.与原始SSD模型比较,本文所提模型的检测性能得到改善.