Colorectal cancer screening

Signals elicited by transforming growth factor-beta (TGF-beta) superfamily ligands are generated following the formation of heteromeric receptor complexes consisting of type I and type II receptors. TAK1, a member of the MAP kinase kinase kinase family, and its activator, TAB1, participate in the bone morphogenetic protein (BMP) signaling pathway involved in mesoderm induction and patterning in early Xenopus embryos. However, the events leading from receptor activation to TAK1 activation remain to be identified. A yeast interaction screen was used to search for proteins that function in the pathway linking the receptors and TAB1-TAK1. The human X-chromosome-linked inhibitor of apoptosis protein (XIAP) was isolated as a TAB1-binding protein. XIAP associated not only with TAB1 but also with the BMP receptors in mammalian cells. Injection of XIAP mRNA into dorsal blastomeres enhanced the ventralization of Xenopus embryos in a TAB1-TAK1-dependent manner. Furthermore, a truncated form of XIAP lacking the TAB1-binding domain partially blocked the expression of ventral mesodermal marker genes induced by a constitutively active BMP type I receptor. These results suggest that XIAP participates in the BMP signaling pathway as a positive regulator linking the BMP receptors and TAB1-TAK1.     

Polymorphic expression of the glutathione S-transferase P1 gene and its susceptibility to Barrett's esophagus and esophageal carcinoma

Factors determining individual susceptibility to esophageal cancer or premalignant Barrett's epithelium are still largely unclear. An imbalance between phase I drug metabolism [e.g., cytochrome P450 (CYP)] and phase II detoxification [e.g., glutathione S-transferase (GST)] may contribute to the development of these diseases. Polymorphic variants in the CYP1A1 gene were described leading to increased levels of bioactive compounds, whereas polymorphisms in GST genes often resulted in impaired detoxification. We studied the frequencies of polymorphic variants in CYP1A1, GSTP1, GSTT1, and GSTM1 genes in 98 patients with Barrett's epithelium and 34 patients with esophageal cancer. The results were compared with those obtained from 247 healthy blood donors. DNA was extracted, and PCR-RFLP methods were used to detect genetic polymorphisms. Chi2 analysis, Spearman rank correlation, and Wilcoxon rank sum tests were used for statistical evaluation. Polymorphisms in CYP1A1, GSTM1, and GSTT1 occurred at an equal frequency in patients and controls. Occurrence of the polymorphic GSTP1b variant in the GSTP1 gene resulted in a significantly lower GST enzyme activity (P < 0.05), and GSTP1b was found significantly more often in patients with Barrett's epithelium (70%; P < 0.001) and patients with esophageal adenocarcinoma (76%; P = 0.005), as compared to healthy blood donors (41%). In conclusion, presence of the GSTP1b allele leads to lower GST enzyme activity levels and, consequently, impaired detoxification. This most important esophageal GST isoform may, therefore, contribute to the development of Barrett's epithelium and adenocarcinoma.     

Finite Element Simulation of Self-Writing Waveguide Formation Through Photopolymerization

This article presents the simulation of the dynamics of the self-writing waveguide phenomenon in photopolymerizable resin systems using the finite element method. The rate equation of the photopolymerization process, mechanical shrinkage in the resin and lightwave propagation through the waveguide are included in the finite element model. An emphasis is placed on the simulation of processes occuring at multiple time scales and the introduction of mechanical shrinkage through an equivalent body force. Simulation results predict the features of self-writing previously observed including nonuniformities in the final polymerized waveguide.     

CARBORUNDUM BRICK1

A study of carborundum-clay mixtures with reference to the relation between the proportioning and sizing of the constituents and the properties of the refractory as expressed by the tensile strength, the load test, the slagging and the spalling tests. For good working conditions the amount of clay must suffice to cover the grains of SiC. When subjected to crushing the linear compression varies as the second power of the percentage of carborundum. Oxidizing furnace conditions and the presence of iron oxide, lead oxide and lime reduce the resistance to slag action. The resistance to spalling depends upon the content of SiC, the tensile strength, the coefficient of expansion and the thermal conductivity of the clay. A formula is proposed for the estimation of the life of the carborundum refractories, and a theoretical explanation of their physical properties is offered.     

高等教育、发展与学习经济(下)

本文考察高等教育、特别是大学在“新经济”中的作用。文章在对新经济的诉求、知识生产的变化、ICT驱动经济活动的集约化效应、和知识网络的开发等面度上,在高等教育与大学应该保持它们传统的批判功能与文化功能的前提下,进行这项考察。     

Errors in working with office computers: A first validation of a taxonomy for observed errors in a field setting

An action‐oriented taxonomy of errors in human‐computer interaction in the office differentiated four classes: functionality problems, usability problems, interaction problems, and inefficient behavior. Functionality problems were differentiated in how they affect the action process. Usability problems were differentiated according to levels of action regulation and steps in the action process. For example, conscious strategies were differentiated from automatic ones. To examine the taxonomy's construct validation, several hypotheses regarding error‐handling time, need for external support, complexity at work, and novices versus experts were tested in a field study of 198 clerical workers at 11 German companies and 7 small firms. A total of 1,749 errors were observed within a 2‐hour period, 1,306 were rated concordantly by two re‐raters. As expected, errors resulting from conscious regulation and functionality problems needed more error‐handling time than errors resulting from more automatic actions. There were more thought and memory errors at workplaces with high complexity. The most external support was needed for knowledge errors. Novices committed more knowledge errors and experts more habit errors. Practical implications are discussed both for software development and training.     

Experiences in Calibrating Industrial Platinum Resistance Sensors Between − 196 °C and 80 °C

Recently, a requirement arose to provide sensors for measuring the temperature of a substantial reference blackbody cavity to operate in vacuum over a temperature range from ? 100 °C to 80 °C (~?170 K to ~?350 K), with an additional capability to operate at ~? 170 °C (~?100 K) as a point of near-zero radiance. Several 100 Ω industrial platinum resistance sensors (Pt100) are required for control purposes in order to establish the temperature uniformity of the blackbody structure and its surrounding aluminum-alloy isothermal shield. These sensors should remain stable within the uncertainties of 0.03 °C (k?=?3) ideally for 20 years. This paper discusses the testing and calibration of two types of industrial Pt100 resistors, including checking the interchangeability of sensors from a given batch, and the methods of interpolation over the temperature range. It is concluded that the sensors can meet the requirements provided that they have been individually tested, and that there is a degree of duplication of sensors so that long-term changes can be detected. The calibration data could be fitted by cubic or quartic equations expressing temperature as a function of resistance (or resistance ratio), this being simpler than the ITS-90 formulation and more convenient than using the (technically obsolete) Callendar–Van Dusen equation.