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Abstract The laboratory has been given a central and distinctive role in science education, and science educators have suggested that rich benefits in learning accrue from using laboratory activities. Twenty years have been elapsed since we published a frequently cited, critical review of the research on the school science laboratory (Hofstein & Lunetta, Rev. Educ. Res. 52 (2), 201–217, 1982). Twenty years later, we are living in an era of dramatic new technology resources and new standards in science education in which learning by inquiry has been given renewed central status. Methodologies for research and assessment that have developed in the last 20 years can help researchers seeking to understand how science laboratory resources are used, how students' work in the laboratory is assessed, and how science laboratory activities can be used by teachers to enhance intended learning outcomes. In that context, we take another look at the school laboratory in the light of contemporary practices and scholarship. This analysis examines scholarship that has emerged in the past 20 years in the context of earlier scholarship, contemporary goals for science learning, current models of how students construct knowledge, and information about how teachers and students engage in science laboratory activities. © 2003 Wiley Periodicals, Inc. Sci Ed 88: 28–54, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.sce10106

Changes in the organization of health services in developing countries have led to the district level assuming more responsibility for the planning, delivery and quality of community health care. This fully up-dated new edition has been produced to help those working in the district laboratory, and those responsible for the organization and management of community laboratory services and the training of district laboratory personnel. Replacing the previous publication Medical Laboratory Manual for Tropical Countries, this book provides an up-to-date practical bench manual, taking a modern approach to the provision of a quality medical laboratory service. It includes practical accounts of: organization and staffing of district laboratory services; total quality management; health and safety; equipping district laboratories; parasitological tests, illustrated in colour; clinical chemistry tests; how to plan a training curriculum for district laboratory personnel. Volume 2, published in late 1999, covers microbiological tests, haematological tests and blood transfusion tests.

This highly original work presents laboratory science in a deliberately skeptical way: as an anthropological approach to the culture of the scientist. Drawing on recent work in literary criticism, the authors study how the social world of the laboratory produces papers and other texts,' and how the scientific vision of reality becomes that set of statements considered, for the time being, too expensive to change. The book is based on field work done by Bruno Latour in Roger Guillemin's laboratory at the Salk Institute and provides an important link between the sociology of modern sciences and laboratory studies in the history of science.

A critical question facing experimental economists is whether behavior inside the laboratory is a good indicator of behavior outside the laboratory. To address that question, we build a model in which the choices that individuals make depend not just on financial implications, but also on the nature and extent of scrutiny by others, the particular context in which a decision is embedded, and the manner in which participants and tasks are selected. We present empirical evidence demonstrating the importance of these various factors. To the extent that lab and naturally occurring environments systematically differ on any of these dimensions, the results obtained inside and outside the lab need not correspond. Focusing on experiments designed to measure social preferences, we discuss the extent to which the existing laboratory results generalize to naturally-occurring markets. We summarize cases where the lab may understate the importance of social preferences as well as instances in which the lab might exaggerate their importance. We conclude by emphasizing the importance of interpreting laboratory and field data through the lens of theory.

Molecular Cloning has served as the foundation of technical expertise in labs worldwide for 30 years. No other manual has been so popular, or so influential. Molecular Cloning, Fourth Edition, by the celebrated founding author Joe Sambrook and new co-author, the distinguished HHMI investigator Michael Green, preserves the highly praised detail and clarity of previous editions and includes specific chapters and protocols commissioned for the book from expert practitioners at Yale, U Mass, Rockefeller University, Texas Tech, Cold Spring Harbor Laboratory, Washington University, and other leading institutions. The theoretical and historical underpinnings of techniques are prominent features of the presentation throughout, information that does much to help trouble-shoot experimental problems. For the fourth edition of this classic work, the content has been entirely recast to include nucleic-acid based methods selected as the most widely used and valuable in molecular and cellular biology laboratories. Core chapters from the third edition have been revised to feature current strategies and approaches to the preparation and cloning of nucleic acids, gene transfer, and expression analysis. They are augmented by 12 new chapters which show how DNA, RNA, and proteins should be prepared, evaluated, and manipulated, and how data generation and analysis can be handled. The new content includes methods for studying interactions between cellular components, such as microarrays, next-generation sequencing technologies, RNA interference, and epigenetic analysis using DNA methylation techniques and chromatin immunoprecipitation. To make sense of the wealth of data produced by these techniques, a bioinformatics chapter describes the use of analytical tools for comparing sequences of genes and proteins and identifying common expression patterns among sets of genes. Building on thirty years of trust, reliability, and authority, the fourth edition of Mol

Many members of the Academy of Pediatrics seem to be generally unaware of the fact that your Academy has participated for ten years in a very interesting and valuable organization, the National Committee for Clinical Laboratory Standards (NCCLS). The NCCLS has only three kinds of members: professional organizations, industrial (clinical laboratory instruments and supplies), and government agencies (CDC, FDA, NBS, NIH). Each member is represented by one delegate and one alternate. At present there are close to 110 members, of which 20 are professional societies.

Manipulating the Mouse Embryo: A Laboratory Manual by B. Hogan, F. Constantini and E. Lacy, Cold Spring Havi~ Laboratmy, 1986. $60.00 (332 pages) ISBN 0 87969 175 1 These are heady days for developmental biologists. Prob- lems that have puzzled scientists for centuries seem to be moving tom the realm of abstract philosophy towards practical solo ution. The power of recombinant DNA technology fuels this opti- mism; at last genes can be engineered, inserted, located, monitored, neutralized and their impact on development asses- sed. The prospect of interfering positively, rather than randomly, with the genetic basis for development is real. The prac- tical basis for this optimism, as recorded in this manual, is clearly well founded. It is impressive that so much pro- gress in the genetic manipulation of the mouse has been made so rapidly. Here are recorded the tech- niques for preparing, inserting and analysing DNA sequences, for retroviral infection of em- bryos, for production and use of EC and EK cells as vehicles for engineered sequences and for nuclear transplantation - all this against a background of the basic procedures required for pro- ducing and handling the em- bryos. If there is one critidsm, it is that the format and content of manual do reveal a fashionable, but perhaps a rather narrow, belief that it is by gene injection (or variants of it) alone that the problem of development will be solved. One might expect a laboratory manual entitled Manilmlating the Mouse Embryo to inform about more general practical aspects of mouse em- bryology than are contained here

BACKGROUND: The study of microbial communities has been revolutionised in recent years by the widespread adoption of culture independent analytical techniques such as 16S rRNA gene sequencing and metagenomics. One potential confounder of these sequence-based approaches is the presence of contamination in DNA extraction kits and other laboratory reagents. RESULTS: In this study we demonstrate that contaminating DNA is ubiquitous in commonly used DNA extraction kits and other laboratory reagents, varies greatly in composition between different kits and kit batches, and that this contamination critically impacts results obtained from samples containing a low microbial biomass. Contamination impacts both PCR-based 16S rRNA gene surveys and shotgun metagenomics. We provide an extensive list of potential contaminating genera, and guidelines on how to mitigate the effects of contamination. CONCLUSIONS: These results suggest that caution should be advised when applying sequence-based techniques to the study of microbiota present in low biomass environments. Concurrent sequencing of negative control samples is strongly advised.

Abstract Method validation is one of the measures universally recognized as a necessary part of a comprehensive system of quality assurance in analytical chemistry. In the past, ISO, IUPAC, and AOAC International have cooperated to produce agreed protocols or guidelines on the "Design, conduct and interpretation of method performance studies" [1], on the "Proficiency testing of (chemical) analytical laboratories" [2], on "Internal quality control in analytical chemistry laboratories" [3], and on "The use of recovery information in analytical measurement" [4]. The Working Group that produced these protocols/guidelines has now been mandated by IUPAC to prepare guidelines on the single-laboratory validation of methods of analysis. These guidelines provide minimum recommendations on procedures that should be employed to ensure adequate validation of analytical methods. A draft of the guidelines has been discussed at an International Symposium on the Harmonization of Quality Assurance Systems in Chemical Laboratory, the proceedings from which have been published by the UK Royal Society of Chemistry.

In these times of burgeoning medical technology and runaway costs, it is a pleasure to find a medical textbook that emphasizes the more basic aspects of practice.<i>Clinical Methods</i>, now in its third edition, reviews the history and physical examination in depth. In addition, the book offers brief discussions of selected laboratory methods used in diagnosis. Compared with previous editions, this volume has undergone extensive revision both in content and organization. Following a brief overview, it is divided into sections based on organ systems. The introductory section includes a useful and well-written chapter on the sensitivity, specificity, and predictive value of laboratory tests, as well as a chapter that takes on the difficult task of articulating the thought processes that are used in the collection and interpretation of medical data. The bulk of the text comprises a detailed discussion of the history and physical examination as related to a particular

Strains of mice that show characteristic patterns of behavior are critical for research in neurobehavioral genetics. Possible confounding influences of the laboratory environment were studied in several inbred strains and one null mutant by simultaneous testing in three laboratories on a battery of six behaviors. Apparatus, test protocols, and many environmental variables were rigorously equated. Strains differed markedly in all behaviors, and despite standardization, there were systematic differences in behavior across labs. For some tests, the magnitude of genetic differences depended upon the specific testing lab. Thus, experiments characterizing mutants may yield results that are idiosyncratic to a particular laboratory.

Manual of clinical laboratory immunology , Manual of clinical laboratory immunology , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

This paper describes a protocol for induction of moderate psychological stress in a laboratory setting and evaluates its effects on physiological responses. The 'Trier Social Stress Test' (TSST) mainly consists of an anticipation period (10 min) and a test period (10 min) in which the subjects have to deliver a free speech and perform mental arithmetic in front of an audience. In six independent studies this protocol has been found to induce considerable changes in the concentration of ACTH, cortisol (serum and saliva), GH, prolactin as well as significant increases in heart rate. As for salivary cortisol levels, the TSST reliably led to 2- to 4-fold elevations above baseline with similar peak cortisol concentrations. Studies are summarized in which TSST-induced cortisol increases elucidated some of the multiple variables contributing to the interindividual variation in adrenocortical stress responses. The results suggest that gender, genetics and nicotine consumption can influence the individual's stress responsiveness to psychological stress while personality traits showed no correlation with cortisol responses to TSST stimulation. From these data we conclude that the TSST can serve as a tool for psychobiological research.

This meta-analysis reviews 208 laboratory studies of acute psychological stressors and tests a theoretical model delineating conditions capable of eliciting cortisol responses. Psychological stressors increased cortisol levels; however, effects varied widely across tasks. Consistent with the theoretical model, motivated performance tasks elicited cortisol responses if they were uncontrollable or characterized by social-evaluative threat (task performance could be negatively judged by others), when methodological factors and other stressor characteristics were controlled for. Tasks containing both uncontrollable and social-evaluative elements were associated with the largest cortisol and adrenocorticotropin hormone changes and the longest times to recovery. These findings are consistent with the animal literature on the physiological effects of uncontrollable social threat and contradict the belief that cortisol is responsive to all types of stressors.

ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTNMR Chemical Shifts of Common Laboratory Solvents as Trace ImpuritiesHugo E. Gottlieb, Vadim Kotlyar, and Abraham NudelmanView Author Information Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, IsraelCite this: J. Org. Chem. 1997, 62, 21, 7512–7515Publication Date (Web):October 17, 1997Publication History Received27 June 1997Published online17 October 1997Published inissue 1 October 1997https://pubs.acs.org/doi/10.1021/jo971176vhttps://doi.org/10.1021/jo971176vbrief-reportACS PublicationsCopyright © 1997 American Chemical SocietyRequest reuse permissionsArticle Views779575Altmetric-Citations3033LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Alcohols,Aromatic compounds,Hydrocarbons,Sodium,Solvents Get e-Alerts

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General Clinical Tests. Amino Acids. Blood Bank. Carbohydrates. Complement Factors. Electrolytes. Endocrinology. Enzymology. Erythrocyte Enzymes. Hematology. Hemostasis. Hepatitis Testing. Immunology. Interferences. Internationally Recommended Units. Laboratory Values During Pregnancy. Lipids. Renal Function. Pancreatic and Gastric Function. Porphyrins. Proteins. Toxicology. Trace Metals. Tumor Markers. Urine Screening Tests. Vitamins. Molecular Pathology. Therapeutic Drugs. Microbiology.

▪ Abstract This paper reviews rock friction and the frictional properties of earthquake faults. The basis for rate- and state-dependent friction laws is reviewed. The friction state variable is discussed, including its interpretation as a measure of average asperity contact time and porosity within granular fault gouge. Data are summarized showing that friction evolves even during truly stationary contact, and the connection between modern friction laws and the concept of “static” friction is discussed. Measurements of frictional healing, as evidenced by increasing static friction during quasistationary contact, are reviewed, as are their implications for fault healing. Shear localization in fault gouge is discussed, and the relationship between microstructures and friction is reviewed. These data indicate differences in the behavior of bare rock surfaces as compared to shear within granular fault gouge that can be attributed to dilation within fault gouge. Physical models for the characteristic friction distance are discussed and related to the problem of scaling this parameter to seismic faults. Earthquake afterslip, its relation to laboratory friction data, and the inverse correlation between afterslip and shallow coseismic slip are discussed in the context of a model for afterslip. Recent observations of the absence of afterslip are predicted by the model.