Color Cherenkov imaging of clinical radiation therapy

Color vision is used throughout medicine to interpret the health and status of tissue. Ionizing radiation used in radiation therapy produces broadband white lig...     

电容触摸传感的理论框架

电容触摸传感技术要求时电容或容值的变化进行测量.完成测量有多种方法,但每当模拟硬件采集到数据后,就必须将数据输入给单片机处理.必须对数据进行后处理,比如以数字的形式来表示数据才能使读数具有实际意义.     

Identifying and characterizing social media communities: a socio-semantic network approach to altmetrics

Scientometrics - Altmetric indicators allow exploring and profiling individuals who discuss and share scientific literature in social media. But it is still a challenge to identify and characterize...     

The margarine industry of Europe

Recent mergers, acquisitions by the European margarine trust, and intensive merchandising campaigns throughout Europe to increase the popularity of margarine and expand the consumer markets for the product, have accentuated interest in this industry abroad. This article, therefore, as it embraces all of the leading margarine producing countries of Europe, is offered to fill a want and supply a service of information of particular interest to manufacturers of margarine and producers of other fats for food purposes in the United States. Published by permission of the Bureau.     

CRISPR-Cas Controls Cryptic Prophages

The bacterial archetypal adaptive immune system, CRISPR-Cas, is thought to be repressed in the best-studied bacterium, Escherichia coli K-12. We show here that the E. coli CRISPR-Cas system is active and serves to inhibit its nine defective (i.e., cryptic) prophages. Specifically, compared to the wild-type strain, reducing the amounts of specific interfering RNAs (crRNA) decreases growth by 40%, increases cell death by 700%, and prevents persister cell resuscitation. Similar results were obtained by inactivating CRISPR-Cas by deleting the entire 13 spacer region (CRISPR array); hence, CRISPR-Cas serves to inhibit the remaining deleterious effects of these cryptic prophages, most likely through CRISPR array-derived crRNA binding to cryptic prophage mRNA rather than through cleavage of cryptic prophage DNA, i.e., self-targeting. Consistently, four of the 13 E. coli spacers contain complementary regions to the mRNA sequences of seven cryptic prophages, and inactivation of CRISPR-Cas increases the level of mRNA for lysis protein YdfD of cryptic prophage Qin and lysis protein RzoD of cryptic prophage DLP-12. In addition, lysis is clearly seen via transmission electron microscopy when the whole CRISPR-Cas array is deleted, and eliminating spacer #12, which encodes crRNA with complementary regions for DLP-12 (including rzoD), Rac, Qin (including ydfD), and CP4-57 cryptic prophages, also results in growth inhibition and cell lysis. Therefore, we report the novel results that (i) CRISPR-Cas is active in E. coli and (ii) CRISPR-Cas is used to tame cryptic prophages, likely through RNAi, i.e., unlike with active lysogens, active CRISPR-Cas and cryptic prophages may stably co-exist.