Ergonomic Chair Design by Fusing Qualitative and Quantitative Criteria Using Interactive Genetic Algorithms

This paper emphasizes the necessity of formally bringing qualitative and quantitative criteria of ergonomic design together, and provides a novel complementary design framework with this aim. Within this framework, different design criteria are viewed as optimization objectives, and design solutions are iteratively improved through the cooperative efforts of computer and user. The framework is rooted in multiobjective optimization, genetic algorithms, and interactive user evaluation. Three different algorithms based on the framework are developed, and tested with an ergonomic chair design problem. The parallel and multiobjective approaches show promising results in fitness convergence, design diversity, and user satisfaction metrics.     

How good are clinical MEDLINE searches? A comparative study of clinical end-user and librarian searches

The objective of this study was to determine the quality of MEDLINE searches done by physicians, physician trainees, and expert searchers (clinicians and librarians). Its design was an analytic survey with independent replication in a setting of self-service online searching from medical wards, an intensive care unit, a coronary care unit, an emergency room, and an ambulatory clinic in a 300-bed teaching hospital. Participating were all M.D. clinical clerks, house, and attending staff responsible for patients in the above settings. Intervention for all participants consisted of a 2-h small group class and 1-h practice session on MEDLINE searching (GRATEFUL MED) before free access to MEDLINE. Search questions from 104 randomly selected novice searches were given to 1 of 13 clinicians with prior search experience and 1 of 3 librarians to run independent searches (triplicated searches). Measurements and main results from these unique citations of the triplicated searches were sent to expert clinicians to rate for relevance (7-point scale). Recall (number of relevant citations retrieved from an individual search divided by the total number of relevant citations from all searches on the same topic) and precision (proportion of relevant citations retrieved in each search) were calculated. Librarians were significantly better than novices for both. Librarians had equivalent recall to, and better precision than, experienced end-users. Unexpectedly, only 20% of relevant citations were retrieved by more than one search of the set of three, with the conclusion that novice searchers on MEDLINE via GRATEFUL MED after brief training have relatively low recall and precision. Recall improves with experience but precision remains suboptimal. Further research is needed to determine the "learning curve," evaluate training interventions, and explore the non-overlapping retrieval of relevant citations by different searchers.     

Human melanocytes and keratinocytes exposed to UVB or UVA in vivo show comparable levels of thymine dimers

Epidemiology shows a relationship between solar exposure and all types of skin cancer. Understanding the mechanisms of skin cancer requires knowledge of the photomolecular events that occur within the relevant epidermal cell types in vivo. Studies to date have focused on UVR-induced DNA lesions in keratinocytes, the majority epidermal cell population which gives rise to most skin cancers. Malignant melanoma, arising from melanocytes (5%-10% of epidermal cells), accounts for most skin cancer deaths. We report on new techniques to detect DNA photolesions in human epidermal melanocytes in situ. Previously nonexposed buttock skin of volunteers of skin types I/II was exposed to clinically relevant doses of narrow bandwidth UVB (300 nm) and UVA (320 nm, 340 nm, 360 nm) radiation. Biopsies were taken immediately afterwards and processed for routine histology. Microscope sections were prepared and double-stained with fluorescent-tagged monoclonal antibodies for thymine dimers and melanocytes. UVR dose-response curves for dimer levels within melanocyte nuclei were determined by image analysis and compared with dimer levels in adjacent basal cell keratinocytes. Our data show that UVB and UVA readily induce thymine dimers in melanocytes at levels that are comparable with those found in adjacent keratinocytes. This new technique will enable melanocyte specific studies, such as DNA repair kinetics, to be done in vivo.     

The production of experimentally labelled aerosols in the sub-micron range

An apparatus for the production of labelled, stable, insoluble particles of ferric oxide in the size range 0·08–0·5 μ is described. The apparatus has a high overall efficiency, and is very suitable for cases when the amount of material to be nebulized is limited.

The characteristics of the particles are examined and the rapid variation of particle density with particle size is studied and explained on a simple semi-empirical theory.     

Electron spin resonance study of the role of calcium in the fibrinogen-fibrin reaction

For the first time a study has been made of the fibrinogen-fibrin conversion using electron spin resonance spectroscopy. Marked differences in spectra of the fibrin were observed with increasing calcium content of the clotting media. A model is proposed for the environment of the calcium in fibrin which involves either glutamic or aspartic acid residues in addition to histidine and tyrosine residues. The model proposed would explain the accelerating effect calciumions have on the conversion of monomeric fibrin to urea-soluble polymeric fibrin and the essential role they play in the formation of the insoluble physiological clot.     

GRASP - Gamma Ray Astronomy with Spectroscopy and Positioning

The GRASP telescope, which is currently under assessment by the European Space Agency as a future space mission, is designed to generate high resolution images of the gamma-ray sky with high sensitivity and fine spectral resolution. The telescope employs a coded aperture mask and the capability to function as a Spectral Imager is achieved by the incorporation of an array of discrete aermanium solid state detectors within the matrix of a larger position sensitive CsI(Tl) gamma-ray detection plane.     

光定时系统设计

2003.3/下半月 www.eepw.com.cn电子产品世界本文给出一个简单、完整的传感器基测量系统设计，该系统是用测量两个光束隔断的时间来测量运动物体的速度。此设计包括显示和状态指示器、时间保持和控制功能所需的所有数字逻辑以及连接提供光感测功能的IR(红外)LED和光二极管所必须的模拟信号处理。系统测量经过时间范围是毫秒~分钟量级。本系统有4个主要的子系统(见图1)：用户接口，传感器接口/接收器，计数器/显示逻辑和主机控制逻辑。用户接口由7位LED数字显示(显示经过时间)、几个状态LED和两个按钮开关(RESE…     

Local and regional anesthesia for functional endoscopic sinus surgery

An effective topical and regional anesthetic technique using 25% cocaine paste combined with intravenous midazolam hydrochloride was used in 554 patients undergoing functional endoscopic sinus surgery. The operative fields were excellent and all procedures were completed with little patient disturbance. Patients recovered rapidly from sedation and were usually fit for discharge on the same day. There were no anesthetic complications. The major surgical complication rate was 0.5%.     

Cell-free V(D)J recombination

V(D)J recombination generates diversity in the immune system through the lymphoid-specific assembly of multiple gene segments into functional immunoglobulin and T-cell receptor genes. The first step in V(D)J recombination is cleavage of DNA at recombination signal sequences. Cleavage produces a blunt DNA end on each signal sequence and a hairpin end on adjacent coding gene segments, and can be reproduced in vitro by using purified RAG and RAG2 proteins. The later steps involve processing and joining of the cleaved DNA ends, and until now have been studied only in cells. Here we reconstitute the complete V(D)J recombination reaction in a cell-free system. We find that the RAG proteins are not only involved in cleavage, but are also needed in the later steps for efficient joining of coding ends. Joining is largely directed by short pieces of identical sequence in the coding flanks, but addition of human DNA ligase I results in greater diversity. Coding junctions contain short deletions as well as additions complementary to a coding flank (P nucleotides). Addition of non-templated nucleotides into coding junctions is mediated by terminal deoxyribonucleotidyl transferase. The cell-free reaction can therefore reproduce the complete set of processing events that occur in cells.