Bias Sources and Corrections in TEOM Technology.

Researchers at the National Institute for Occupational Safety and Health have used tapered element oscillating microbalances (TEOM) in laboratory settings. The TEOMs have assessed the mass concentration of laboratory-generated particulates in experimental dust chambers and provided a reference method for comparison with other particulate-measuring instruments. Current NIOSH research is focused on further adapting TEOM technology as a wearable personal dust monitor (PDM) for coal mine workers. The history of TEOM technology describes the oscillating tapered tube mathematically as a simple harmonic oscillator. However, analysis of the new PDM test data showed a bias dependency on the starting frequency f o. This result prompted a rigorous investigation to uncover the source of the bias and if the bias source is applicable to the 1400 TEOM. Based on the above results, a significantly improved theoretical description of TEOM performance has been developed. Average bias for each group of PDMs is calculated and compared to the results of the accuracy tests performed. Accompanying these biases are estimates of the average bias spans of the new PDMs in comparison to the pre-commercial PDMs. The theory was also applied to the Model 1400 TEOM data to evaluate whether there is agreement. The new theory of TEOM operation provides a good account for both the bias and bias span. Given that TEOM technology has been used for decades around the world to monitor atmospheric particulate contaminants as well as many other aerosols, quantification and correction of this source of bias should result in more accurate assessments.

Comparative susceptibility of Atlantic salmon, lake trout and rainbow trout to Myxobolus cerebralis in controlled laboratory exposures.

The susceptibility of lake trout Salvelinus namaycush, rainbow trout Oncorhynchus mykiss and Atlantic salmon Salmo salar to Myxobolus cerebralis, the causative agent of whirling disease, was compared in controlled laboratory exposures. A total of 450 (225 for each dose) fry for each species were exposed to a low (200 spores per fish) or high (2000 spores per fish) dose of the infective triactinomyxon. At 22 wk post-exposure, 60 fish from each group, as well as controls for each species, were examined for clinical signs (whirling behavior, blacktail, deformed heads and skeletal deformities), microscopic lesions, and presence of spores. Rainbow trout were highly susceptible to infection, with 100% being positive for spores and with microscopic pathological changes in both exposure groups. Rainbow trout were the only species to show whirling behavior and blacktail. Atlantic salmon were less susceptible, with only 44 and 61% being positive for spores, respectively, in the low and high dose groups, while 68 and 75%, respectively, had microscopic pathology associated with cartilage damage. Rainbow trout heads contained mean spore concentrations of 2.2 (low dose) or 4.0 (high dose) x 10(6) spores g tissue(-1). The means for positive Atlantic salmon (not including zero values) were 1.7 (low) and 7.4 (high) x 10(4) spores g tissue(-1). Lake trout showed no clinical signs of infection, were negative for spores in both groups and showed no histopathological signs of M. cerebralis infection.

Modified constraint induced therapy: a randomized feasibility and efficacy study.

This case series examined the feasibility and efficacy of a modified constraint induced therapy (CIT) protocol administered on an outpatient basis. The Fugl-Meyer Assessment of Motor Recovery After Stroke (Fugl), Action Research Arm Test (ARA), Wolf Motor Function Test (WMFT), and Motor Activity Log (MAL) were administered to six patients between 2 and 6 months poststroke (CVA) exhibiting stable motor deficits and learned nonuse of the affected limb. Two patients then participated in half-hour physical and occupational therapy sessions three times/week for 10 weeks. During the same period, their unaffected arms and hands were restrained 5 days/week during 5 hours identified as times of frequent use. Two other patients received regular therapy and two control patients received no therapy. The ARA, Fugl, WMFT, and MAL were again administered after 10 weeks. Patients receiving modified CIT exhibited substantial improvements on the Fugl, ARA, and WMFT, as well as increases in amount and quality of use of the limb using the MAL. Patients receiving traditional or no therapy exhibited no improvements. Results suggest that modified CIT may be an efficacious method of improving function and use of the affected arms of patients exhibiting learned nonuse.

Mental practice combined with physical practice for upper-limb motor deficit in subacute stroke.

BACKGROUND AND PURPOSE: This case report describes a patient with upper-limb hemiparesis (ULH) who received a program combining physical therapy for the affected side with mental practice. CASE DESCRIPTION: The patient was a 56-year-old man with stable motor deficits, including ULH, on his dominant side resulting from a right parietal infarct that occurred 5 months previously. He received physical therapy for an hour 3 times a week for 6 weeks. In addition, 2 times a week the patient listened to an audiotape instructing him to imagine himself functionally using the affected limb. The patient also listened to the audiotape at home 2 times a week. Pretreatment and posttreatment measures were the upper-extremity scale of the Fugl-Meyer Assessment of Sensorimotor Impairment (Fugl-Meyer Scale), the Action Research Arm Test (ARA), and the Stroke Rehabilitation Assessment of Movement (STREAM). OUTCOMES: The patient exhibited reduction in impairment (Fugl-Meyer Scale) and improvement in arm function, as measured by the ARA and STREAM. DISCUSSION: Mental practice may complement physical therapy to improve motor function after stroke.

A randomized efficacy and feasibility study of imagery in acute stroke.

OBJECTIVE: To compare the feasibility and efficacy of a programme combining imagery and occupational therapy with a programme of therapy only. DESIGN: Randomized, controlled case series. SETTING: Subacute outpatient clinic. SUBJECTS: Thirteen consecutively admitted patients between four weeks and one year post stroke exhibiting stable motor deficits in their affected upper limbs. INTERVENTION: All patients received an hour of therapy three times a week for six weeks administered by the same physical and occupational therapists. During the same period, eight patients participated in 10-minute guided imagery sessions after each therapy session, as well as practising imagery at home twice each week. Five patients participated in a control intervention consisting of exposure to stroke information. MAIN OUTCOME MEASURES: The Fugl-Meyer Assessment of Motor Recovery (Fugl-Meyer) and Action Research Arm Test (ARA). RESULTS: After intervention, Fugl-Meyer and ARA scores of patients in the therapy only group remained virtually the same; therapy plus imagery group scores improved by 13.8 and 16.4 points, respectively, on the Fugl-Meyer and ARA. CONCLUSIONS: Imagery is a clinically feasible, cost-effective complement to therapy that may improve outcomes more than participation in therapy only.

Coordinated and adequately funded state streams for rehabilitation of newly injured persons with tbi.

Traumatic brain injury (TBI) rates are highest among families with the lowest income levels. A paucity of appropriate funding streams for low-income, recently injured TBI patients is reported to cause delays in provision of early postacute rehabilitation or to cause patients to be discharged without receiving rehabilitation. There are also reports of patients remaining in hospitals with minimal care or being returned home, both because of a lack of a discharge site. The purposes of this exploratory study were to: (1) identify model aspects of existing publicly supported and administered programs for postacute individuals with TBI; (2) present results of a survey measuring to what extent state Medicaid programs fund postacute rehabilitation services for recently injured patients with TBI; (3) present results of interviews with trauma center social workers affiliated with the National Institute on Disability and Rehabilitation Research (NIDRR) TBI Model Systems projects to determine whether and how delays in receiving Medicaid coverage occur; and (4) make recommendations for improved systems of care for postacute individuals with TBI.

Mental practice: a promising restorative technique in stroke rehabilitation.

Upper limb hemiparesis is a common, yet debilitating, result of stroke. It has long been known that mental practice, when combined with physical practice, improves motor learning and performance. Recent studies also indicate that massed use of the affected arm results in cortical reorganizations and correlative functional improvements. During mental practice, there are widespread activations of neural and muscular mechanisms as if the arm were actually being used. This article introduces mental practice as a form of massed practice, reviews the bases for mental practice as a potent restorative technique, and presents data suggesting mental practice as a restorative technique for upper limb hemiparesis.

Exploring competitive orientation in a group of athletes participating in the 1996 paralympic trials.

The purposes of this study were to test (1) whether athletes with congenital disabilities exhibited different competitive orientations than athletes with disabilities acquired during their lifespans and (2) whether male athletes with disabilities exhibited different competitive orientations than their female peers. 54 paraplegic, quadriplegic and amputee athletes competing in the 1996 Paralympic Track and Field Trials completed the Sport Orientation Questionnaire. No mean differences were found between men and women, athletes with different onsets of their disabilities across the lifespan, between adolescents and adults, and between athletes with different severity classifications on the Goal orientation, Competitiveness, and Desire to win scales. Larger studies are encouraged to examine competitive orientation, as well as scores on tests specifically constructed to be administered to athletes with disabilities.

Particulate penetration of porous foam used as a low flow rate respirable dust size classifier.

Porous foam has been used as a material for classification of particulate matter into various size fractions. The penetration characteristics of a nominal 90 pores per inch porous foam were studied at various flow rates, face velocities, and foam plug diameters and compared to the aerosol penetration of a 10 mm Dorr Oliver cyclone operated at 1.7 L/min. Poly-dispersed triethanolamine spheres were classified through porous foam plugs and the resulting penetration was determined using an aerodynamic particle sizer. Results showed that for a given plug diameter, as face velocity increased from 26 to 39 cm/sec, the 50 percent cut point decreased from 4.5 to 3.8 microns. Furthermore, as the diameter of the plug increased from 4 to 12 mm, the 50 percent cut points were similar to other plug diameters at equivalent face velocities. The best match to the 1.7 L/min cyclone penetration characteristics occurred at a flow rate of 250 ml/min through a 25 mm by 4 mm diameter section of 90 pore per inch foam. Because of the need to provide short-term or real-time estimates of worker respirable dust exposure, porous foam may be a viable classification media for a low flow rate, disposable respirable dust sampler for use in the coal mining industry.

Laboratory evaluation of pressure differential-based respirable dust detector tube.

Assessment of exposure to occupational dusts is a first step in reducing exposures to harmful dust concentrations. A new type of respirable dust sampler was developed and compared side-by-side to personal gravimetric samplers in the laboratory. The new sampler correlates filter back pressure with mass accumulation to provide mid-shift- and end-of-shift determinations of cumulative exposure. The sampler uses a small low flow rate pump to draw dust through a small detector tube that contains a porous urethane foam respirable classification section and glass fiber filter that collects respirable dust. Six different coal dusts were aerosolized in a laboratory dust chamber and a total of 119 triplicate observations were obtained. For individual coal types, the correlation coefficients were between 0.87 and 0.97. The precision of the two methods was similar, with the percent relative standard deviation of the personal samplers of 12 percent and the new detector method of 14 percent. For all coal types tested th data were best described by a power function where delta P = 1.43 mass (0.85), with a correlation coefficient of 0.73. The method becomes more accurate at higher dust loadings such that all laboratory data with mass loadings greater than an equivalent concentration of 2 mg/m3 fall within +/- 25 percent of the power function. Assessment of the method under field conditions is in progress.

Safety in New Zealand's adventure tourism industry: the client accident experience of adventure tourism operators.

BACKGROUND: Injuries and fatalities among participants of adventure tourism activities have the potential to seriously impact on New Zealand's tourism industry. However, the absence of statistics for tourist accidents in New Zealand, and the lack of detailed academic research into adventure tourism safety, means the extent of the problem is unknown. The aims of the present study were to determine the incidence of client injuries across a range of adventure tourism activity sectors, and to identify common accident events and contributory risk factors. METHOD: A postal questionnaire survey of New Zealand adventure tourism operators was used. Operators were asked to provide information related to their business; the number of recorded client injuries during the preceding 12 month period, January to December 1998; common accident and injury events associated with their activity; and perceived risk factors for accidents in their sector of the adventure tourism industry. RESULTS: The survey was responded to by 142 New Zealand adventure tourism operators. The operators' reported client injury experience suggests the incidence of serious client injuries is very low. Highest client injury incidence rates were found for activities that involved the risk of falling from a moving vehicle or animal (e.g., cycle tours, quad biking, horse riding, and white-water rafting). Slips, trips, and falls on the level were common accident events across most sectors of the industry. Perceived accident/incident causes were most commonly related to the client, and in particular, failure to attend to and follow instructions. CONCLUSIONS: The prevalence of client injuries in activity sectors not presently covered by government regulation, suggests policy makers should look again at extending codes of practice to a wider range of adventure tourism activities. Further research considering adventure tourism involvement in overseas visitor hospitalized injuries in New Zealand, is currently in progress. This will provide supporting evidence for the risk associated with participation in a range of commercial and independently undertaken adventure activities.

Conditioned grooming induced by the dopamine D1-like receptor agonist SKF 38393 in rats.

Stimulation of dopamine D1-like receptors reliably increases grooming in rats and mice. The study examined whether the grooming response elicited by the prototypical D1-like agonist SKF 38393 (8 mg/kg s.c.) could be conditioned to the specific environment in which it occurred. Rats in one group (Paired) received SKF 38393 and rats in another group (Unpaired) received saline in observation boxes outside of their housing room; the rats were then scored for duration and frequency of grooming bouts over 25 min. The ordering of injections was reversed the next day in the rats, housing room. The procedure was repeated twice, with at least one intervening drug-free day, to give three conditioning trials. The D1-like agonist significantly increased grooming on each of the three conditioning trials, without obvious tolerance or sensitization, and the effect tended to persist for the duration of each trial. On the test trial for conditioned grooming, mean grooming duration was significantly greater in the Paired than the Unpaired group, suggesting that SKF 38393-induced grooming had been conditioned to the test environment. This is the first time that drug-elicited grooming has been conditioned to environmental cues.

Estimation of lamb carcass composition from measurements of the speed of ultrasound in the soft tissues of live animals and carcasses.

The application of the velocity of sound (VOS) technique to lamb carcasses in a previous study (Fisher & Page, 1986) measured composition at a hind limb and neck site but was not as precise as fat scores in predicting lean proportion. This study examines VOS measurements made at sites in the hind limbs and along the vertebral column in live sheep and carcasses. A group (A) comprising five breeds of males and females (n = 61) and a sub-group (B) of Scottish Blackface castrated males (n = 34) were studied, and the reciprocal velocity of ultrasound (RV) was measured on the live sheep immediately behind the shoulder and over the last rib using a fixed-distance transducer assembly operating at 5 MHz, and in the hind limbs at 2·25 MHz using the apparatus described by Miles et al. (1984). Corresponding measurements were made on the carcasses which were classified by a Meat and Livestock Commission fatstock officer and then dissected. Standard deviations of lean proportion were 4·48% (A) and 3·39% (B). The residual standard deviations (rsds) for groups A and B respectively were obtained using the following predictors: live mass (LM) 4·27% and 2·96%; LM + breed (B) 3·08% (group A only); LM + mean RV 2·36% and 2·07%; LM + B + mean RV 1·99% (group A only). Using carcass measurements: carcass mass (CM) 4·25% and 2·90%; CM + MLC fat score 2·99% and 2·12%; CM + RV last rib 2·89% and 2·02%. These data show that VOS measurements through dorsal sites of live sheep provide encouragingly precise estimates of carcass lean proportion. For carcasses, dorsal sites provide a less precise estimate of carcass lean but when carcass mass is included in multiple regression the precision of the correlation is comparable with that of multiple regression of fat score with carcass mass.

Clay occlusion of respirable quartz particles detected by low voltage scanning electron microscopy-X-ray analysis.

Respirable-sized dust particles from a clay mine and mill were examined for aluminium and silicon content by scanning electron microscopy-energy dispersive X-ray analysis at incident electron energies of 5-20 keV. Most of the high silica content particles, those which had a silicon to silicon plus aluminium signal fraction, measured at 20 keV, of 0.9 or greater, showed a decrease in the silicon fraction of signal with decreasing incident electron energy, down to values of between 0.6 and 0.8 at 5 keV: this decrease was a function of particle size and composition. Simple models for silicon fraction of signal vs incident electron voltage suggest this behaviour is due to a heterogeneous particle structure in which an aluminosilicate coating occludes the surface of a silica particle core. The coating survives incubation in a major component of pulmonary surfactant.

Progress towards using the speed of ultrasound for beef leanness classification.

Following the observation of a high correlation between the reciprocal of the speed of ultrasound and lean proportion in beef carcasses, commercial equipment (VOSI) was developed and its performance alongside a smaller assembly (Mini G) is reported. The speed of ultrasound was measured through six sites on beef carcasses within 1 h of stunning: three sites with VOSI and three sites with Mini G. Sides were also scored for fatness and conformation using the EAAP system, and subcutaneous fat depth was measured at 25,50 and 75% of the width of M. longissimus thoracis from the midline at the last rib. All sides were dissected into subcutaneous fat, intermuscular fat, muscle and bone. The reciprocal speed averaged over the three VOSI sites (RV346) was the best single predictor of the proportion of lean in the side. Multiple regression analyses, in predicting per cent lean, showed that addition of conformation score improved the precision of fat score and fat depth for a group of 26 sides. It did not provide a significant improvement over RV346. However, in another group of 50 sides showing more variation in side mass and conformation, conformation score did significantly improve RV346. The best prediction of per cent lean, involving RV346 and tissue thicknesses, gave a residual standard deviation of 1·35%, and conformation score did not significantly improve this regression.

Estimating beef carcass composition using the speed of ultrasound.

The reciprocal of the speed of 2·25 MHz (nominal) ultrasound (RV) was measured at selected sites through the soft tissues of 72 beef carcasses from Friesian. Hereford and Hereford × Friesian bulls and steers at or within 1 h of stunning. The measurement sites were: through M. adductor horizontal to the caudal edge of the symphysis pubis (S2), through M. scalenus just cranial to the first rib (S3) and through M. longissimus thoracis between the tenth and eleventh ribs, approximately 6 cm from the midline (S4). The thickness of extractable lipid (d(f)) at each site was defined as the product ßd, where ß was the volume fraction of extractable lipid and d was the tissue thickness. The thickness of lipid-free tissue (d(ff)) was defined as (d-d(f)) and ß was calculated from the ultrasonic measurements using an empirical linear relation between ß and RV. When cold, the intact sides were scored independently for fatness and conformation by two experienced judges according to the EAAP system and their mean scores determined. Sides were split at the level of the last rib and the depth of subcutaneous fat measured at 25%, 50% and 75% of the width of M. longissimus thoracis from the midline. The three ultrasonic characteristics (RV, d(f) and d(ff)) at each site, the mean fat depth and the mean fat and conformation scores were examined for correlation with % fat and % lean in the sides determined by complete physical dissection. The best predictors of % fat were mean d(f) at S3 and S4, mean d(f) at S2, S3 and S4 and mean EAAP fat score which were all of comparable precision (rsd, respectively, 2·07, 2·06 and 2·08). The best predictors of % muscle were mean d(f) at S3 and S4, mean d(f) at S2, S3 and S4 and mean RV at S2, S3 and S4 (rsd, respectively, 1·79, 1·79 and 1·90). The corresponding residual standard deviations for mean EAAP fat score and mean fat depth were 2·18 and 2·20.