光纤布拉格光栅传感特性及实验研究

本文分析了光纤布拉格光栅传感温度和应变的基本原理及其灵敏度,构建了光纤布拉格光栅传感特性实验系统,介绍了光路系统的组成结构、原理及其相关器件特性,完成了温度和应变量的测量实验。实验结果表明,采用光纤布拉格光栅能够实现应变和温度的测量,从而证明了光纤布拉格光栅传感技术理论分析的正确性和实验系统设计的合理性。     

On-chip deposition of carbon nanotubes using CMOS microhotplates

The direct deposition of carbon nanotubes on CMOS microhotplates is demonstrated in this paper. Tungsten microhotplates, fabricated on thin SOI membranes aside CMOS control circuitry, are used to locally grow carbon nanotubes by chemical vapour deposition. Unlike bulk heating of the entire chip, which could cause degradation to CMOS devices and interconnects due to high growth temperatures in excess of 500?°C, this novel technique allows carbon nanotubes to be grown on-chip in localized regions. The microfabricated heaters are thermally isolated from the rest of the CMOS chip as they are on the membranes. This allows carbon nanotubes to be grown alongside CMOS circuitry on the same wafer without any external heating, thus enabling new applications (e.g.?smart gas sensing) where the integration of CMOS and carbon nanotubes is required.     

Strategies for teaching older people to use the World Wide Web

Information is increasingly displayed digitally, yet less than half of the population of the UK use the Internet. Older people are especially unlikely to be Internet users and the consequent risks of digital exclusion must be addressed. A training course in computers and web use for older adults took place at the University of Dundee, with 15 participants. The course approach was to simplify application interfaces and to ensure that basic skills were learnt before more complicated tasks were presented. As part of this process, there was a focus on learning to use the computer before learners were introduced to the web with its wide variety of content. The course outcomes were positive and the authors report them here in order to reflect upon the experience and help others who set out to provide training for older people in web use.

Relative impact of oxidative stress on the functional competence and genomic integrity of human spermatozoa

Reactive oxygen metabolites are known to disrupt sperm-oocyte fusion, sperm movement, and DNA integrity; however, the relative sensitivities of these elements to oxidative stress are unknown. In this study these factors were assessed in human spermatozoa exposed to increasing levels of oxidative stress achieved through the stimulation of endogenous oxidant generation with NADPH or direct exposure to hydrogen peroxide. At low levels of oxidative stress, DNA fragmentation was significantly reduced while the rates of sperm-oocyte fusion were significantly enhanced. As the level of oxidative stress increased, the spermatozoa exhibited significantly elevated levels of DNA damage (p < 0.001) and yet continued to express an enhanced capacity for sperm-oocyte fusion. At the highest levels of oxidative stress, extremely high rates of DNA fragmentation were observed but the spermatozoa exhibited a parallel loss in their capacities for movement and oocyte fusion. These studies emphasize how redox mechanisms can either enhance or disrupt the functional and genomic integrity of human spermatozoa depending on the intensity of the oxidative stimulus. Because these qualities are affected at different rates, spermatozoa exhibiting significant DNA damage are still capable of fertilizing the oocyte. These results may have long-term implications for the safety of assisted conception procedures in cases associated with oxidative stress.     

Interhemispheric subdural hematoma in adults: case reports and a review of the literature

The interhemispheric subdural hematoma is a relatively uncommon type of subdural hematoma, especially seen in patients with blood clotting disturbances. When its mass becomes sufficiently large, specific neurological abnormalities such as hemiparesis and signs of the falx syndrome are seen. Treatment can consist of conservative observation or craniotomy and is dictated by the clinical course. Conservative management is the treatment of choice for patients without disturbances of consciousness and for patients with stable clinical conditions. Surgical treatment is necessary in patients with progressive deterioration. Three case reports are presented, as well as a review of 64 cases described in the literature. The salient aspects of this clinical entity are discussed.