Laboratory Situations Research Articles

Workshop on Comparative Radiobiology and Protection of theEnvironment Dublin, 21-24 October 2000

Workshop on Comparative Radiobiology and Protection of theEnvironment Dublin, 21-24 October 2000

Actual stress, psychopathology and salivary cortisol levels in the irritable bowel syndrome (IBS).

Although irritable bowel syndrome (IBS) can be considered a biopsychological disorder in which an association between life stress and physiological changes leading to bowel irregularity is present, there is a lack of data concerning possible modifications of the adrenal function during the disease. The aim of the present study was to measure biological and psychological variables related to the activity of the hypothalamo-pituitary-adrenal axis in IBS patients compared to healthy subjects. Cortisol was measured in the saliva (obtained by a stress-free, non invasive collection procedure) of 55 IBS outpatients and 28 matched controls. Moreover, each subject completed the following self-administered questionnaires: the Rome Burnout Inventory (RBI) in its physical (RBI-PE) and emotional-mental exhaustion (RBI-EME) components, Beck Depression Inventory, State and Trait Anxiety Inventory (STAI), Perceived Social Support Scale (PSSS) and a Scale for the Assessment of Perceived Actual Work-Non Work Stress. Compared with controls, IBS subjects showed significantly higher levels of cortisol in the morning and lower in the evening, while they maintained the physiological circadian fluctuation (i.e. cortisol morning level higher than in the evening). Moreover, IBS patients presented a significant difference from controls in RBI-PE scores, which confirms the presence of fatigue, a symptom frequently reported by the patients. Compared with controls, no differences were found in IBS patients with respect to other psychological parameters. These findings suggest a dysregulation of the adrenal activity in IBS patients. The results may be relevant considering that changes in cortisol levels have been shown to be sensitive indicators of psychosocial stress and coping patterns in both laboratory and life situations.

Mobile phones and driving - the UK perspective on government policy

Although there are clear benefits in having mobile phones available in vehicles, there are also potential disbenefits from a safety viewpoint. These have been demonstrated in laboratory situations, in simulators and the road environment. Epidemiological studies also suggest that distraction effects while using a phone can contribute to accidents. The potential benefits of having a phone available in a vehicle, e.g. summoning assistance in the event of a breakdown or alerting emergency services to an incident, must be weighed against the potential risks from a driver using a phone, either hand-held or hands-free, when controlling the vehicle. This paper provides as overview and summary of current GB policy on the use of mobile phones when driving.

A Review of the Effects of Multiple Stressors on Aquatic Organisms and Analysis of Uncertainty Factors for Use in Risk Assessment

Risk assessment procedures use toxicity tests in which organisms are subjected to chemicals under otherwise constant and favorable experimental conditions. Because variable and suboptimal environmental conditions are common aspects of natural ecosystems, the hazard of underestimation of risk arises. Therefore, an uncertainty factor is used in the extrapolation of results of standard toxicity tests to field situations. The choice for these uncertainty factors is based on little ecological evidence. This review discusses studies on the toxicity of various chemicals to aquatic organisms, modified by temperature, nutritional state and salinity, excluding papers on changes in bioavailability of compounds. Collected data were analyzed quantitatively to evaluate the validity of toxicity data obtained from standard toxicity tests in the laboratory under field conditions. Generally, organisms living under conditions close to their environmental tolerance limits appeared to be more vulnerable to additional chemical stress. Usually, increasing temperature and decreasing food or nutrient level raised toxicity. The influence of salinity was less clear; metal toxicity increased with decreasing salinity, toxicity of organophosphate insecticides increased with higher salinity, while for other chemicals no clear relationship between toxicity and salinity was observed. The interactions can be explained by several physical and physiological processes, acting on factors such as bioavailability, toxicokinetics, and sensitivity of organisms. Quantitative analysis of data indicated that an uncertainty factor for the laboratory to field extrapolation should be smaller than one for an ecosystem in a temperate region, while a factor greater than one would be appropriate for systems nearby discharge points of cooling water. The factor should be greater than one when varying nutritional state is concerned, but smaller than one with respect to salinity. Dependent on the effect parameter used, the differences in toxicity between laboratory and relevant field situations ranged from a factor of 2.6 to 130 and 1.7 to 15 for the two temperature conditions and 1.2 to 10 for nutritional state. A salinity increase from freshwater to marine water decreased toxicity by a factor of 2.1. However, as less extreme salinity changes are more relevant under field conditions, the change in toxicity is probably much smaller. To obtain uncertainty factors that sufficiently protect natural systems without being overprotective, additional research is required.

The effect of freezing and thawing fresh grass silage on near infrared reflectance spectroscopy (NIRS) predictions

The accurate analysis of forage is paramount if the nutritive value to the ruminant animal is to be estimated. NIRS has the potential to accurately and rapidly evaluate the chemical and biological parameters of fresh silage. In many laboratory situations the pressure of proximate and specialized chemical analyses means that routinely, fresh forages have to be stored frozen (–20°C) before analysis. Research by MacRae et al., (1975) has shown that although the physico-chemical composition of high quality forages changed upon freezing and subsequent thawing there were no differences in the apparent digestibilities and total nitrogen remained relatively constant. The objective of this study was to examine the effect of freezing and thawing fresh silage on NIRS predictions.

The Food Situations Questionnaire: a measure of children's willingness to try novel foods in stimulating and non-stimulating situations

This paper reports the development and validation of a self-report measure of food neophobia for children. Items described hypothetical situations in which novel foods might be encountered and asked children to report how they would feel about tasting or eating them. Ten items, representing two correlated subscales, were selected from among a larger number, using standard item selection measures with a total of 335 children, aged 7–12 years. The two subscales represent willingness to try novel foods in highly stimulating circumstances and willingness to try novel foods in non-stimulating circumstances. The test was shown to significantly predict actual willingness to taste novel foods in a laboratory situation. In addition, it was shown to predict such willingness better than parents' reports of the children's neophobia. Finally, the test was shown to have satisfactory internal and test–retest reliabilities.

Turbulence and laminar structures: can they co-exist?

Schwarzschild first suggested that the laminar structures observed in the high Reynolds number Re = UL/nu approx. = (10(exp 12)) solar photosphere are the result of turbulence rather than a proof of its absence. He reasoned that since turbulence generates large turbulent viscosities nu(sub t) much greater than nu, the effective Reynolds number Re = UL/nu(sub t) approx. = O(1). Schwarzschild's argument is, however, incomplete for it assumes that the entire role of the non-linear interactions is to enhance viscosity. While this is not true in general, we present a proof of how and why it may occur, thus completing Schwarzschild's argument. We further discuss the fact that the same model non-local turbulence models have been shown to reproduce LES data for a variety of flows pertaining to astrophysics, geophysics and laboratory situations (at a fraction of the time).

Release of Metals by the Leaves of the Salt Marsh Grasses Spartina alterniflora and Phragmites australis

The perennial grass Spartina alterniflora, common to salt marshes of eastern North America, is known to accumulate metals from marsh sediment and release them into the environment. One pathway by which Spartina alterniflora releases metals is through the excretion of metal-containing salts produced by leaf salt glands. We examined the differential release of metals by Spartina alterniflora and the invasive perennial grass Phragmites australis in an urban marsh ecosystem. Leaching rates were measured by cleaning residues off leaf surfaces under field and controlled laboratory conditions. Leaf residues and leaf tissue were analysed for copper, chromium, lead and zinc by atomic absorption spectrophotometry.Spartina alterniflora was found to release significantly more metal through leaf tissue than Phragmites australis, under both field and laboratory situations. Spartina alterniflora was also found to accumulate significantly more chromium and lead in leaves than Phragmites australis. Therefore, Spartina alterniflora can release larger quantities of metals into the marsh environment than Phragmites australis, through both excretion and leaf deposition.

Driver Misperception of Maneuver Opportunities and Requirements

Misperceptions of the time available or time required for various driving maneuvers under a range of conditions were studied. In the laboratory experiment, research participants viewed video scenes of a wide variety of situations and made judgments about when some event would occur (e.g., approaching vehicle reaches them) or when some maneuver would be completed (e.g., own vehicle clears roadway when making a crossing maneuver). Participants' judgments were compared with objectively determined values. A parallel on-road experiment, using similar procedures and a subset of the laboratory situations, was used to validate and benchmark the laboratory findings. The study found a general tendency for people to underestimate the time required for a maneuver. This misjudgment is safety-critical, because it may lead to decisions to accept maneuver opportunities that actually afford a smaller margin of error than the driver perceives. Such misestimates were particularly common for judgments of the time to achieve the prevailing traffic speed during turning or merging maneuvers, and for the time until one's vehicle reaches an intersection ahead. For judgments of the time available for a maneuver, people more frequently felt they had less time than they actually did, so would be less likely to attempt a maneuver. However, even for time available judgments, there were meaningful numbers of safety-critical errors. Some situations emerged as particularly meriting consideration for safety countermeasures. These included: (1) approach to signalized intersections; (2) turns onto higher-speed roadways; (3) freeway merges; (4) passing; and (5) headway maintenance. A number of promising countermeasure ideas addressing these issues were developed and recommended for formal evaluation.

Attention and Mental Workload

Mental workload is still a useful concept in human factors because of its links to theories and models of attention. A good theory is the best practical tool. Mental workload is defined as an intervening variable similar to attention. It must be inferred from changes in performance. Performance declines when mental workload is too high or too low. Results from simple laboratory situations cannot necessarily be generalized directly to practical situations which tend to be more complex. Instead, laboratory experiments are used to refine models and theories that can be applied to solve practical problems. Computational models of attention and workload offer the greatest promise for practitioners. Examples of research on driver workload illustrate the dangers of applying secondary-task methodology without adequate consideration of theoretical issues.

Chlorophyll fluorescence—a practical guide

typically written from a biophysicist’s or a molecular plant physiologist’s point of view (Horton and Bowyer, Chlorophyll fluorescence analysis has become one of 1990; Krause and Weis, 1991; Govindjee, 1995). The aim the most powerful and widely used techniques avail- of this review is to provide a simple, practical guide to able to plant physiologists and ecophysiologists. This chlorophyll fluorescence for those beginners who are review aims to provide an introduction for the novice interested in applying the technique in both field and into the methodology and applications of chlorophyll laboratory situations. Whilst the principles behind the fluorescence. After a brief introduction into the theor- measurements will be discussed briefly, the emphasis will etical background of the technique, the methodology be on the applications and limitations of this technique and some of the technical pitfalls that can be encoun- in plant ecophysiology. tered are explained. A selection of examples is then used to illustrate the types of information that fluorescence can provide. The basis of chlorophyll fluorescence measurements

Effect of the carbon source on assessment of degrading bacteria with the spread-plating technique during in situ bioremediation.

Spread-plating belongs to traditional microbiological methods employed for quantification of subsurface microflora during bioremediation projects in the Czechia. Concentration of degrading organisms is estimated from the number of colonies grown on agar plates supplied with contaminant as the sole carbon source. The data obtained during in situ bioremediation of the Dacice site contaminated by cutting oil suggests that changes in the composition of the carbon source in the subsurface may cause a discrepancy between laboratory data and situation in subsurface.

Gender Differences in Spatial Task Performance as a Function of Speed or Accuracy Orientation

Performance differences in spatial abilities as a function of gender may be modified by practice and relevant background experiences, as well as by directions given in laboratory situations. We examined whether a focus on speed or accuracy influenced performance in various spatial domains, using several different scoring techniques. Men and women from a small, predominantly White private college completed tasks of spatial perception, spatial visualization, and mental rotation under one of three conditions: speed-emphasis, accuracy-emphasis, or control. Participants also provided information concerning experiences pertinent to spatial ability. Results revealed relative parity between men and women on tasks of spatial visualization and spatial perception; speed/accuracy orientation did not alter these findings. Men outperformed women on mental rotation, but only when scored in a strict manner and when explicitly told to focus on accuracy, but not when directional emphasis was absent or geared toward speed. Self-reported background in math, sports, and the arts was unrelated to performance. The results are discussed in terms of women's efficacy beliefs about performing tasks explicitly designated as spatial in nature.

Micronutrient Policies for Agriculture in Latin America

A key distinguishing feature of Latin America is that 75% of the population is urban, and this proportion is projected to rise to 82% by 2025. Because markets for processed foods are more developed in urban than in rural areas, fortification has a comparative advantage in Latin America relative to other regions. In fact, fortification has been highly successful in Latin America. Salt iodination programmes are the most widespread, followed by fortification of sugar with vitamin A; fortification of wheat with thiamine, riboflavin, niacin, and folic acid; and fortification of margarine. At least 13 Latin American countries now have vitamin A supplementation programmes, which are relatively new to Latin America. A mix of types of fortification, supplementation, and food-based interventions will be needed in the future. Efforts should continue in the implementation of activities such as home gardens, small-animal production, and promotion of edible, native plants. Genetic manipulation through plant-breeding can alter in a positive way desirable functional properties of foods as well as the concentration and properties of macro- and micronutrients. The benefits of functional characteristics bred into plants have been clearly demonstrated (e.g., fatty acid profiles, delayed ripening), but not the benefits for human nutrition, except in laboratory situations. The plant-breeding approach needs additional, interdisciplinary research at various points in the food chain to establish the benefit for human nutrition.

Interferential therapy machines as possible vehicles for cross-infection

Interferential therapy machines are used to apply alternating electric currents to patients for the treatment of various musculo-skeletal complaints. The potential for such machines to transfer skin microflora from one patient to another during treatment was investigated. The efficacy of the current disinfection procedure of the machines was also evaluated. In both the laboratory and clinical situation, interferential treatment, (which involves the direct application of electrodes to the skin surface) resulted in the transfer of micro-organisms from the skin of one subject to another. To decrease the likelihood of transmission of micro-organisms via interferential therapy machines, it is recommended that both the suction cups and sponges are disinfected with 70% isopropyl alcohol after the treatment of each patient. The use of disposable electrodes could also be considered.

Multicentre evaluation of the Boehringer Mannheim/Hitachi 917 analysis system

The new selective access analysis system BM/Hitachi 917 was evaluated in an international multicentre study, mainly according to the ECCLS protocol for the evaluation of analysers in clinical chemistry. Forty-three different analytes, covering 56 different methods enzymes, substrates, electrolytes, specific proteins, drugs and urine applications were tested in seven European clinical chemistry laboratories. Additionally, the practicability of the BM/ Hitachi 917 was tested according to a standardized questionnaire. Within-run CVs (median of 3 days) for enzymes, substrates and electrolytes were <2% except for creatine-kinase MB isoform and lipase at low concentration. For proteins, drugs and urine analytes the within-run CVs were < 4% except for digoxin and albumin in urine. Between-day median CVs were generally < 3% for enzymes, substrates and electrolytes, and < 6% for proteins, drugs and urine analytes, except for lipase, creatine kinase and MB isoform, D-dimer, glycosylated haemoglobin, rheumatoid factors, digoxin, digitoxin, theophylline and albumin in urine in some materials. Linearity was found according to the test specifications or better and there were no relevant effects seen in drift and carry-over testing. The interference results clearly show that also for the BM/Hitachi 917 interference exists sometimes, as could be expected because of the chemistries applied. It is a situation that can be found in equivalent analysers as well. The accuracy is acceptable regarding a 95–105% recovery in standard reference material, with the exception of the creatinine Jaffé method. Most of the 160 method comparisons showed acceptable agreement according to our criteria: enzymes, substrates, urine analytes deviation of slope ± 5%, electrolytes ± 3%, and proteins and drugs ± 10%. The assessment of practicability for 14 groups of attributes resulted in a grading of one–three scores better for the BM/Hitachi 917 than the present laboratory situation. In conclusion, the results of the study showed good analytical performance and confirmed the usefulness of the system as a consolidated workstation in medium-sized to large clinical chemistry laboratories.

Standardized Comparison of Processing Capacity and Efficiency of Five New-Generation Immunoassay Analyzers

With the trend toward laboratory and workstation consolidation, more studies are necessary to evaluate instrumentation, solutions for coping with workflow and test diversity, and opportunities for increasing the overall efficiency of laboratory testing. We assessed the processing capacity and efficiency of new-generation immunoassay analyzers by determining productivity parameters of five commercially available systems. A workload protocol was developed and used to assess processing capacity and efficiency parameters of five immunoassay analyzers under standardized conditions in a real-life routine situation. We studied the ACS:Centaur((R)) (analyzer A), Architect(TM) i2000 (analyzer B), Elecsys((R)) 2010 tandem (analyzer C), Immulite((R)) 2000 (analyzer D), and Vitros ECi (analyzer E) on the basis of a standardized workload protocol that reflected a routine laboratory situation. This workload encompassed reflex and STAT testing, dilutions, and in-run calibration of a new reagent lot number. The analyzers were compared for hands-on labor time, unattended time (UT), throughput, and differentiated relative productivity indexes [RPI((UT)); number of reportable results/(processing time - sum of unattended time)]. The RPI data for analyzers linked to an automated (aut) sample-handling system [RPI((aut))] were also calculated. The evaluation produced a set of parameters for the productivity of the instruments. An overview of the most important parameters revealed the following: the throughput was 193, 123, 97, 109, and 46 tests/hour for instruments A, B, C, D and E, respectively; the RPI((10)) was 425, 238, 161, 445, and 151 tests/operator-hour; the RPI((30)) was 229, 136, 118, 264, and 86 tests/operator-hour; the RPI((10,aut)) was 1701, 637, 235, 964, and 223 tests/operator-hour; and the RPI((30, aut)) was 298, 150, 174, 400, and 114 tests/operator-hour. The combination of a standardized workload protocol and determination of parameters for productivity and labor efficiency, especially the differentiated RPIs, made it possible to make an objective comparison of the organizational consequences of the use of these instruments. The described parameters allow for a scientifically based choice, given a certain workflow and a particular laboratory organization.

Health care system and laboratory medicine in Austria: present status and future perspectives

In the recent past, the role of laboratory medicine has changed from merely supplier of analytical data to supplier of results together with clinical interpretation. In addition, the role of medical laboratories as important partners of health care management by providing data for management functions and decisions is rapidly growing. The article has the purpose of giving an overview of Austria’s population, the governmental system and Austrian health politics in context with European health care. The existing health care system with its historical development, to-date status and recent changes due to socio-economic pressure are outlined. Special emphasis is given to the present situation of medical laboratories in Austria. Furthermore, hospital management strategies and some adjustment processes in the authors’ clinical-medical laboratory to alleviate the ongoing economic pressure are described. As far as possible, an attempt of forecasting future scenarios is made.

The Minolta SPAD-502 Leaf Chlorophyll Meter: An Exciting New Tool for Education in the Plant Sciences

Research Article| November 01 1999 The Minolta SPAD-502 Leaf Chlorophyll Meter: An Exciting New Tool for Education in the Plant Sciences John Markwell, John Markwell Search for other works by this author on: This Site PubMed Google Scholar Dale Blevins Dale Blevins Search for other works by this author on: This Site PubMed Google Scholar The American Biology Teacher (1999) 61 (9): 672–676. https://doi.org/10.2307/4450800 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation John Markwell, Dale Blevins; The Minolta SPAD-502 Leaf Chlorophyll Meter: An Exciting New Tool for Education in the Plant Sciences. The American Biology Teacher 1 November 1999; 61 (9): 672–676. doi: https://doi.org/10.2307/4450800 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentThe American Biology Teacher Search This content is only available via PDF. Copyright The National Association of Biology Teachers Article PDF first page preview Close Modal You do not currently have access to this content.

Social problem-solving abilities and adjustment to recent-onset spinal cord injury.

Timothy R. ElliottUniversity of Alabama at BirminghamABSTRACT. Objective: To examine the relation of social problem-solving abilitiesto psychological and physical adjustment of persons with recent spinal cord injuries(SCIs). Design: Correlational procedures were used. Participants: One hundredeighty-six persons with recent SCI completed self-report measures during inpatientrehabilitation; 94 returned for an annual evaluation. Main Outcome Measures:Acceptance of disability, career needs, and pressure sore diagnoses. Results: Greaternegative problem orientation predicted each self-report outcome variable; complete-ness of lesion was the best predictor of pressure sore diagnosis. Conclusions: Theproblem orientation component appears to relate to self-reported adjustment amongpersons with SCI in a theoretically consistent fashion.Social problem solving entails the instrumental, cognitive-behavioral attitudesand skills necessary for adjustment in everyday life and for coping effectivelywith events encountered in living (D'Zurilla & Nezu, 1982). Because mostproblems are encountered within a social and interpersonal context, the emphasison social problem solving distinguishes these skills from the more purelycognitive abilities studied in controlled laboratory situations (D'Zurilla & Maydeu-Olivares, 1995). Contemporary models stipulate that social problem-solvingattitudes and skills are implicated in the prevention, development, and mainte-nance of adjustment difficulties experienced by people in general (D'Zurilla N Nezu & D'Zurilla, 1989).Timothy R. Elliott, Department of Physical Medicine and Rehabilitation, University ofAlabama at Birmingham.This study was supported by a grant from the National Institute on Disability andRehabilitation Research (H133N5009). Appreciation is extended to Andrew Palmatier forhis assistance in collecting and managing data and to Michael DeVivo for his statisticaladvice.Correspondence concerning this article should be addressed to Timothy R. Elliott, PhD,1717 Sixth Avenue South, 530 Spain Rehabilitation Center, University of Alabama,Birmingham, Alabama 35233. Electronic mail may be sent to telliott@uab.edu.315