Where are we in understanding the effects of where we are?

This paper briefly reviews research studies of interest to environmental ergonomists. It includes some recent work on the health effects of office lighting, especially the effects of daylighting, fluorescent lighting and full-spectrum lighting. It also covers studies of indoor air quality in offices, especially investigations of localized air filtration and the sick building syndrome. It argues the value of a systematic, ergonomics approach to designing the built environment.     

Identification of a class 3 aldehyde dehydrogenase in human saliva and increased levels of this enzyme, glutathione S-transferases, and DT-diaphorase in the saliva of subjects who continually ingest large quantities of coffee or broccoli

Human saliva was tested for the presence of cytosolic class 3 aldehyde dehydrogenase, glutathione S-transferases alpha, mu, and pi, and DT-diaphorase, enzymes that are known to catalyze the biotransformation of many xenobiotics, including some that are carcinogens and some that are antineoplastic agents. Each of these enzymes was found to be present in this fluid. Inducers of these enzymes are known to be abundantly present in the human diet, especially in certain vegetables and fruits. Further investigation revealed that the salivary content of these enzymes rapidly, coordinately, and markedly increased upon daily consumption of relatively large amounts of coffee or broccoli. The enzyme activities of interest rapidly returned to basal levels when these substances were removed from the diet. Given the important role that cytosolic class 3 aldehyde dehydrogenase, the glutathione S-transferases, and DT-diaphorase are thought to play in determining the carcinogenic potential of some cancer-producing agents as well as the cytotoxic potential of some antineoplastic agents, and assuming that their salivary levels reflect their tissue levels, quantification of the salivary content of one or more of these enzymes, a noninvasive and relatively easy undertaking, could be useful in: (a) preliminarily assessing the chemopreventive potential of various diets and drugs; (b) establishing the optimal dose and schedule in Phase I clinical trials for any putatively chemopreventive diets or drugs of interest; and (c) the rational selection and use of chemotherapeutic agents, since several are inactivated, and a few are activated, by these enzymes; alternatively, the antineoplastic agent could be selected first and then a diet that enables the agent to achieve its full therapeutic potential would be selected based on whether high or low enzyme activity would be favorable in that regard. Such measurements may also be useful as an indicator when exposure to carcinogenic/teratogenic/otherwise toxic environmental/industrial/dietary agents that induce these enzymes is suspected.     

Comparison of 0.25% ropivacaine and bupivacaine for epidural analgesia for labor and vaginal delivery

STUDY OBJECTIVE: Part 1: To measure ropivacaine levels in the mother and infant at delivery after continuous lumbar epidural infusion. Part 2: To compare epidural ropivacaine to epidural bupivacaine for labor analgesia in regard to effectiveness, motor blockade, and maternal and neonatal effects. DESIGN: Part 1: Open-labelled, non-blind study. Part 2: Randomized, double-blind study. SETTING: Labor and delivery units of two academic hospitals. PATIENTS: Part 1: 20 ASA physical status I and II parturients in active labor. Part 2: 81 ASA physical status I and II parturients in active labor. INTERVENTIONS: For Part 1, 8 to 12 ml of 0.25% ropivacaine was administered through a lumbar epidural catheter to achieve a T10 dermatomal sensory level. An infusion of 0.25% ropivacaine, 8 to 10 ml/hr, maintained this sensory level. Maternal and umbilical cord blood samples obtained at delivery were analyzed for ropivacaine concentration. For Part 2, anesthetic management was similar to that previously described except patients were randomized to receive either 0.25% ropivacaine or 0.25% bupivacaine. Onset, regression, maximal spread of sensory block, and onset and degree of motor blockade were measured. Contraction pain as assessed using a visual analog scale (VAS), maternal blood pressure, and heart rate were determined every 5 minutes until a stable VAS-contraction score was achieved, and every 30 minutes thereafter. Neonatal assessment included Apgar scores and neurologic and adaptive capacity scores (NACS) at 15 minutes, 2 hours, and 24 hours. MEASUREMENTS AND MAIN RESULTS: For Part 1, the total and free maternal arterial concentrations of ropivacaine at delivery were 0.64 +/- 0.14 microgram/ml and 0.10 +/- .02 microgram/ml, respectively; the umbilical venous total and free concentrations were 0.19 +/- 0.03 microgram/ml and 0.12 +/- 0.07 microgram/ml, respectively (n = 12). The umbilical arterial and venous concentrations did not differ for both the free and total concentrations. For Part 2, there was no difference between ropivacaine and bupivacaine in the variables measured. Umbilical cord gases and Apgar scores were not different between the two groups; NACS were higher at 15 minutes and 2 hours in the ropivacaine group (p < 0.05) than the bupivacaine group. CONCLUSION: Both ropivacaine and bupivacaine produced excellent analgesia for labor with no major adverse effect on the mother or neonate.     

Comparison of Self-Administered Questionnaire with Physician Diagnosis in the Diagnosis of the Sick Building Syndrome

The aim of the study was to compare the results of a self-administered questionnaire, designed to estimate the prevalence of the sick building syndrome, with an independent medical interview and clinical opinion. Six buildings were chosen for study from a sample of 47 with known measurements of the building symptom index. One building with a high and one with a low score was selected from each of three ventilation classes (natural ventilation, air-conditioning with induction units and air-conditioning with variable air volume systems). A stratified random sample of 160 workers in these buildings was studied. Each received, in random order, a self-administered questionnaire, and a medical opinion based on a free medical history. The doctor had no access to the self-administered questionnaire at the time. The average number of work-related symptoms per worker (the building symptom index), which is used to compare one building with another, showed a good agreement between the two methods. There were, however, consistent differences between the two assessments in individual symptoms. The self-administered questionnaire produced a higher prevalence of work-re- lated runny nose and flu-like symptoms, which were often regarded as being due to infections in the medical opinion. In individuals, work-related symptoms on the self-administered questionnaire were validated by the medical opinion in over 75% of cases for eye and throat symptoms, lethargy and headache. Only 31% of work-related runny nose and 21% of work-related flu-like symptoms were thought by the medical opinion to be work-related. The medical opinion identified an extra 5% of work-related symptoms that were missed on the self-administered questionnaire. The self-administered questionnaire therefore produced a satisfactory estimate of the building symptom index, removing the potential bias of an interviewer. The questions on ninny nose and flu-like symptoms would be improved by including only those that occurred more frequently. The building symptom index was calculated for the six buildings twice, with separate random samples of workers completing the questionnaire two years apart. The buildings were ranked in the same order (for the building symptom index) on both occasions, again confirming the validity of the self-administered questionnaire.     

Improving the accuracy of performance evaluations: Comparison of three methods of performance appraiser training.

A total of 52 supervisory personnel were trained under one of three performance-appraisal training programs: rater error (response set) training, observation training, or decision-making training. Halo, leniency, range restriction, and accuracy measures were collected before and after training from the three training groups and a no-training control group. The results suggested that although the traditional rater error training, best characterized as inappropriate response set training, reduced the classic rater errors (or statistical effects), it also detrimentally affected rating accuracy. However, observation and decision-making training caused performance rating accuracy to increase after training, but did little to reduce classic rater effects. The need for a reconceptualization of rater training content and measurement focus was discussed in terms of the uncertain relation between statistical rating effects and accuracy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Construct validity of multiple job performance measures using confirmatory factor analysis.

The construct validity of job performance ratings obtained from self, supervisors, and peers was assessed relative to performance data obtained from an objective test of task proficiency. Data were gathered from a sample of 256 first-term jet engine mechanics in the U.S. Air Force. Widaman's (1985) approach to assessment of convergent and discriminant validity of multitrait–multimethod data using confirmatory factor analysis to contrast alternative models was used. As expected, all analyses revealed support for a model with correlated performance traits and uncorrelated methods. Significant convergence among the three rating sources was found. In addition, convergence was found between task ratings and scores from the objective proficiency test. Significant discriminant validity was found in all of the analyses. Results revealed that self, supervisors, and peers can be equally valid as sources of performance information, although performance of some tasks may be more validly evaluated by one source than another. Needs for further research on the effects of task characteristics on the validity of ratings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Surface finishing of Ni–Cr–B–Si composite coatings by precision grinding

A Ni–Cr–B–Si/10vol%WC coating material has been precision ground to an optical quality surface finish (<10 nm R_a) using a combination of a very stiff precision machine tool, Tetraform “C”, 76 μm CBN grinding wheels and electrolytic in-process dressing (ELID) assisted grinding. When grinding without ELID, surface finish has been shown to be limited by damage to primary and secondary carbides. This damage may be in the form of carbide pull-out or localised fracture and removal of the larger primary WC particulate. ELID assisted grinding helps maintain CBN grit protrusion and sharpness and thus promotes efficient cutting during grinding, minimising pull-out and localised damage to the harder phases within the coating microstructure. ELID therefore improves both the overall surface finish and surface integrity of the workpiece.     

Effects of keyboard tray geometry on upper body posture and comfort

The effects of a downward-tilting (DT) keyboard tray on wrist posture, seated posture and self-assessed musculoskeletal discomfort were investigated in a field experiment. Thirty-eight professional office workers were studied. A pretest assessed how they typed using either a conventional keyboard on a desk or on an articulating keyboard tray, and with or without wrist rests. Workers were randomly allocated to a control (n = 15) or test group (n = 23) that used their existing keyboard in a DT system. A post-test was conducted 3 weeks later. Results showed no significant changes in wrist posture, seated posture or reports of musculoskeletal discomfort for the control group, and approximately 50% of typing wrist movements put the hand in a neutral zone. There were significant improvements in wrist posture, seated posture and upper body musculoskeletal discomfort for the test group using the DT system. Over 80% of typing wrist movements put the hand into a neutral zone with the DT arrangement. Reactions to using a conventional keyboard on a DT system were positive.