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At least 73 records · Page 4Linked to original sources
PubMed1999

Rethinking the health services insurance system: a new model for Iranian railroad households.

During 1995 and 1996, a 10% stratified random sample of 2124 people representing permanent Iranian railroad workers in 12 provinces was selected to survey the use of health services by personnel and their families. Data were collected from 2107 workers through interviews using a structured questionnaire. The objective was to determine demographic and health characteristics and user satisfaction in order to improve the present delivery of the health insurance system. A new plan for the delivery of health insurance, which focuses upon social accountability and community orientation and is based on the roles of family doctors and nurses in railroad health posts, is proposed and evaluated.

Adolescent↗
PubMed2000

Sickness benefits. Railroad Retirement Board. Final rule.

The Railroad Retirement Board (Board) hereby amends its regulations under the Railroad Unemployment Insurance Act (RUIA) to permit a "nurse practitioner" to execute a statement of sickness in support of payments of sickness benefits under the RUIA. The Board does not currently accept statements executed by a nurse practitioner, which in some cases may delay payment of benefits.

Disability Evaluation↗
PubMed1991

Drug and alcohol involvement in railroad accidents.

Postaccident testing of railroad employees for drugs and alcohol was performed in 175 qualifying accidents or incidents (events) from April 1987 through March 1988. Initial tests for drugs were performed on urine, and for alcohol on blood. Presumptive positives were confirmed and quantitated using both blood and urine when available. In 42 of these events (24%), at least 1 employee tested positive (6.7% of 736 employees) for drugs or alcohol. A higher proportion of drug or alcohol-positive events, or both, 40 versus 21%, was found when a fatality was involved. In 11 of the 32 fully investigated drug or alcohol-positive events (involving 14 employees), the investigating agencies determined that substance use was determined to be a probable cause of, or a factor relating to, the accident. Cannabinoids, ethanol, cocaine, or multiple-drug use were found in 5, 3, 3, and 3 of those employees, respectively. Detectable drug and alcohol use occurs among railroad employees; occasionally it has resulted in accidents.

Accidents↗
PubMed1977

Thirteenth valuation of the railroad retirement system.

The most recent valuation of the financial condition of the railroad retirement system reveals that an existing actuarial deficiency will become more pronounced over time unless corrective action is taken. After projecting the progress of the fund under present law and certain assumptions about the future, the Railroad Retirement Board has concluded that the present value of benefits can be maintained only if the tax rate--already considerably higher for employers than under the social security program--is raised. An immediate increase of 4.1 percent of taxable payroll is required to effect an actuarial balance. Alternatively, a rise of 2.6 percent would be sufficient to prolong the fund until the year 2001. If the present tax rate is not changed, the fund is projected to run out in 1986.

Accounting↗
PubMed2006

Active-site properties of Phrixotrix railroad worm green and red bioluminescence-eliciting luciferases.

The luciferases of the railroad worm Phrixotrix (Coleoptera: Phengodidae) are the only beetle luciferases that naturally produce true red bioluminescence. Previously, we cloned the green- (PxGR) and red-emitting (PxRE) luciferases of railroad worms Phrixotrix viviani and P. hirtus[OLE1]. These luciferases were expressed and purified, and their active-site properties were determined. The red-emitting PxRE luciferase displays flash-like kinetics, whereas PxGR luciferase displays slow-type kinetics. The substrate affinities and catalytic efficiency of PxRE luciferase are also higher than those of PxGR luciferase. Fluorescence studies with 8-anilino-1-naphthalene sulfonic acid and 6-p-toluidino-2-naphthalene sulfonic acid showed that the PxRE luciferase luciferin-binding site is more polar than that of PxGR luciferase, and it is sensitive to guanidine. Mutagenesis and modelling studies suggest that several invariant residues in the putative luciferin-binding site of PxRE luciferase cannot interact with excited oxyluciferin. These results suggest that one portion of the luciferin-binding site of the red-emitting luciferase is tighter than that of PxGR luciferase, whereas the other portion could be more open and polar.

Animals↗
PubMed1988

Physical fitness and cardiovascular disease mortality. The US Railroad Study.

The relation between physical fitness and cardiovascular disease mortality was examined in US railroad workers, as a part of the Seven Countries Study. A cohort of 3,043 white, middle-aged men initially aged 22-79 years were first examined in 1957-1960 and re-examined in 1962-1964. Men with clinically diagnosed cardiovascular disease (n = 465) were excluded from this study. This cohort was followed until death or 1977. Mortality was monitored through the Railroad Retirement Board. Physical fitness was ascertained by a sub-maximal treadmill test administered in a Pullman Car converted to a survey laboratory. Exercise heart rate was directly and significantly related to coronary heart disease mortality, cardiovascular disease mortality, and all-cause mortality after adjusting for age. These relations were greatly attenuated when adjusted for blood pressure level. The risk for coronary heart disease when an exercise test heart rate of 135 beats per minute was compared with a rate of 105 beats per minute was 1.43, after adjusting for age, and 1.20, after adjusting for blood pressure, serum cholesterol levels, and smoking, as well as age. Results from this study suggest that middle-aged men with lower levels of physical fitness, as shown by higher sub-maximal exercise test heart rates, are at greater risk of dying of coronary heart disease, cardiovascular disease, and all causes in an average follow-up of 20 years. This greater risk is largely due to higher blood pressure levels.

Adult↗
PubMed1988

Relative risk of mesothelioma among railroad machinists exposed to chrysotile.

This study challenges the assertion of low relative risk of chrysotile in the causation of mesothelioma. Data are provided on the time period use of various types of asbestos in the United States and in insulation materials. The focus of the study is on mesothelioma among railroad machinists employed in the steam locomotive era who were exposed to chrysotile. Within a cohort of machinists alive January 1, 1945, a sub-cohort method was applied to all successive machinists hired in each of the respective years (1920-1929) followed through 1986. The total cohort was 181 and the number of deaths 156, with 14 mesotheliomas identified among 41 cancer deaths. The findings demonstrated an extremely high relative risk for machinists exposed to chrysotile for the induction of mesothelioma in the individual year of hire cohorts. A similar observation was noted for other crafts hired in the same time period. One mesothelioma occurred for every 13 machinists hired in the succeeding years (1920-1929) and constituted 34% of all cancer deaths. It is concluded that chrysotile is far more hazardous in the induction of mesotheliomas and that the asbestos cancer risk in the steam locomotive eras was much higher than had been previously estimated.

Asbestos↗
PubMed1988

Railroad workers with pleural plaques: I. Spirometric and nitrogen washout investigation on smoking and nonsmoking asbestos-exposed workers.

Eighty-seven workers exposed to asbestos in a railroad car repair shop, with characteristic asbestos-induced pleural plaques, underwent extensive lung-function examination. Vital capacity (VC) showed the greatest reduction among the static lung volumes, with an asymmetrical distribution of one-fourth of the subjects below 80% of the predicted value. Logistic regression demonstrated VC to be sufficient for optimal discrimination of asbestos-exposed subjects from a group of matched controls. No further discriminatory power was gained by additional spirometric measures, lung mechanics, blood gas analysis, or diffusing capacity. Smoking had an influence on dynamic but not on static lung volumes. In conclusion, reduced static lung volumes among smoking asbestos-exposed workers with pleural plaques should, in the absence of other lung diseases, be mainly attributed to the asbestos exposure.

Adult↗
PubMed1988

Railroad workers with pleural plaques: II. Small airway dysfunction among asbestos-exposed workers.

Increased volume of trapped gas (VTG) was found in 87 asbestos-exposed railroad repair shop workers, divided into three subgroups according to smoking habits. All the examined subjects had pleural plaques. Determination of VTG was used to study function of small airways. Increased VTG was found among asbestos-exposed smokers as well as nonsmokers. In both groups the VTG:TLC ratio was elevated compared with controls. Increased VTG is a sign of small airways dysfunction. In asbestos-exposed subjects, it might be caused by an early peribronchial reaction to inhaled asbestos fibers.

Adult↗
PubMed2006

In vivo micronuclei in uncultured T-lymphocytes of male railroad transit workers and referents.

In the biomonitoring of human genotoxic effects, micronuclei (MN) usually are scored in phytohaemagglutinin-stimulated cultured lymphocytes. MN also can be examined in uncultured lymphocytes, which facilitates the analysis of genotoxic damage incurred in vivo. Characterization of MN in cultured lymphocytes by fluorescence in situ hybridization (FISH) has shown a clear over-representation of the X and Y chromosomes in the MN of males. However, it is not known if this phenomenon also occurs in vivo. The purpose of the present study was to assess the frequency and composition of MN formed in vivo from immunomagnetically isolated uncultured T-lymphocytes of men. To evaluate the possible effects of genotoxic exposure on in vivo MN, we examined 17 railroad workers occupationally exposed to complex chemical mixtures and 14 referents, all nonsmokers. The results showed similar total frequencies of micronucleated cells among the exposed workers and the referents. When the MN were characterized by FISH, there were no significant differences between the exposed and referents with regards to the frequency of centromere-positive or centromere-negative MN. Centromeric label was observed in 69% of all MN, indicating that most of the MN contained whole chromosomes (or chromatids). 80% of the centromere-positive MN harbored autosomes, 12% Y chromosomes, and 8% X chromosomes. The occurrence of the Y- and X-chromosomes in MN was, respectively, 5.5- and 3.8-times greater than would be expected assuming an equal contribution by all chromosomes. Thus, sex chromosomes appear to be over-represented in lymphocyte MN of men in vivo, confirming previous results obtained in vitro.

Adult↗
PubMed1994

Psychological, psychosocial, and psychophysiological sequelae in a community affected by a railroad chemical disaster.

Psychological, psychosocial, and psychophysiological sequelae were studied in a community which had experienced a railroad chemical spill of 19,000 gallons of the toxic pesticide metam sodium. Two hundred twenty exposed residents were compared to 114 controls and paired on age, education, gender, race, and number of children. A clinical interview and physiological measurements (blood pressure, pulse, and cortisol level) were taken, the MMPI-2, IES Scale, Mood Scale, Environmental Worry, Perceived Social Support, and Perceived Control Scale and a questionnaire were administered. Results indicated greater levels of depression, anxiety, and somatic symptoms in the spill residents in addition to greater environmental worry and lower perceived social support. Spill residents had higher blood pressure and less fluctuation of cortisol levels than controls. No difference on litigation status was obtained except on the IES, Intrusion and the POMS scales. Chemical disasters are associated with a wide variety of psychological, psychosocial, and physiological distress.

Acute Disease↗
PubMed2005

Impact of railroad ballast type on frontal plane ankle kinematics during walking.

Five healthy male subjects walked on a control surface (level concrete), and two sloped rock surfaces (walking ballast-rock about 1.9 cm across; main line ballast-rock about 3.8 cm across) while their rearfoot motion (defined throughout as ankle inversion/eversion as seen from the frontal plane) was measured to determine if the different walking surfaces caused different ankle kinematics. The ballast was placed in 5m long trays that were tilted 7 degrees in the transverse plane. Rearfoot motion was measured while the subjects walked the length of the respective surfaces wearing work boots. A repeated measures ANOVA and a subsequent multiple comparison test revealed that the rearfoot range of motion was significantly greater walking on the main line ballast than walking on either the walking ballast or the level concrete. Meanwhile, the mean range of rearfoot motion for walking ballast was not significantly different from that resulting from walking on concrete. Variability was more than twice as great walking on main line ballast than walking on level concrete. Rearfoot angular velocities walking on level concrete and walking ballast were not significantly different, but both were significantly less than walking on main line ballast. Results suggested that rearfoot motion could be reduced if railroads placed walking ballast where trainmen have to walk as part of their jobs.

Adult↗
PubMed2004

Boarding and alighting injury experience with different station platform and car entranceway designs on US commuter railroads.

Commuter railroad systems in the US employ three combinations of station platforms and car entranceways. These are high-level platforms with remotely controlled doors and level entranceway (HL-RC), low-level platforms (just above the rail) with steps and remotely controlled doors (LL-RC), and a mixture of the two platform types with a correspondingly more complex, partly manual, door and entranceway arrangement (ML-MO). Much controversy exists over which type of platform/entranceway is better. This seemingly small feature significantly impacts many performance characteristics of these systems, including cost, speed, and boarding and alighting accidents. Northeastern systems are generally moving toward the mixed platform design or all high-level platforms, while systems elsewhere are generally selecting the low-level design. Data on actual accident experience for 1995-2000 are analyzed to determine the effect of platform/entranceway type on passenger and employee injuries. Passenger injury rates on systems with the HL-RC design are lowest, with LL-RC systems next, and ML-MO systems having the highest rates. Employee injury rates are the least on LL-RC systems, but higher on ML-MO and HL-RC systems. Systems with a mixture of high and low platforms (ML-MO) experience a higher overall (combined passenger and employee) injury rate than the other two designs. The implications of these results for both the modernization of existing systems and the design of new systems, in the US and abroad, are discussed.

Accidents, Occupational↗
PubMed1997

A comparison of driver behavior at railroad grade crossings with two different protection systems.

An observational study was conducted which compared the behavior of drivers at a railroad-highway grade crossing as trains approached. The effectiveness of a flasher-only protection system was compared with one incorporating flashers and barrier gates for a particular crossing. The addition of the gates significantly reduced the percentage of drivers crossing in front of trains from 67% to 38%. Plots of crossing probabilities showed them reduced as time until train arrival and the distance of the train from the crossing decreased. Train speed did not seem logically related to the probability of crossing perhaps because it is not well perceived. Drivers crossing around barrier gates tended to stop or slow on approach significantly less than those crossing with flashers only. It was suggested that the gates themselves provided an impediment to crossing which forced drivers inclined to cross into making a hurried and sometimes perilous decision. Their behavior was seen as explaining the surprisingly high number of accidents that occur at barrier-gate crossings. Discouraging drivers from driving around barrier gates was seen as essential if safety at these crossings was to be improved. Extending the length of gates and the education of the drivers regarding the law were seen as possible ways of increasing compliance.

Accidents, Traffic↗
PubMed2004

Forty-year mortality from cardiovascular diseases and all causes of death in the US Railroad cohort of the Seven Countries Study.

Forty-year mortality and its association with entry risk factor levels is reported in men employed in the US Railroad industry within the Seven Countries Study of Cardiovascular Diseases. Cardiovascular risk factors were measured in 2571 men aged 40-59 at entry examination in 1957-1959 and after 5 years. Mortality data were collected during 40 years of follow-up (overall mortality of 83.4%). The main causes of death were coronary heart disease (CHD, 32.9% of all causes using strict criteria), atherosclerotic cardiovascular diseases (including coronary, stroke and peripheral artery diseases, (ACVD), 53.2% of all causes) and cancer (25.1% of all causes). Multivariate analysis showed that age, systolic blood pressure, serum cholesterol and cigarette consumption were strongly and significantly associated with all-cause mortality, coronary mortality and cardiovascular mortality. Multivariate relative risks per 5 years of age were 1.31 for all-causes, 1.32 for CHD and 1.36 for ACVD; per 20 mmHg systolic blood pressure were 1.12, 1.23 and 1.26, respectively; per 1 mmol/l of serum cholesterol were 1.06, 1.18 and 1.14, respectively; and per 10 cigarettes smoked per day were 1.14, 1.12 and 1.13, respectively. During a 40-year period classical cardiovascular risk factors were highly predictive of coronary, cardiovascular and all-cause mortality in a US working population.

Adult↗
PubMed1999

Lung cancer mortality and diesel exhaust: reanalysis of a retrospective cohort study of U.S. railroad workers.

A retrospective cohort study of 55,407 U.S. railroad workers has been called the most definitive study linking exposure to diesel exhaust (DE) with lung cancer in humans. However, reanalysis of data from this study suggests caution in interpreting this study as demonstrating such a link. Although workers who rode trains had a significantly elevated lung cancer mortality relative to clerks and signalmen (who were assumed to be unexposed), shop workers did not, despite convincing evidence that these workers had the highest exposures to DE. Mortality from heart disease and cirrhosis of the liver were also significantly elevated among train riders, which suggests that these workers had a substantially different lifestyle from other workers, and raises the possibility that their elevated lung cancer mortality may be related to lifestyle rather than to DE exposure. Smoking information was not available for this cohort. A positive, monotone dose-response trend in lung cancer mortality with increasing duration of exposure found by the original investigators was not present when age was controlled more carefully and years of exposure quantified more accurately. Instead, a negative dose-response trend for lung cancer was seen among exposed workers based on either duration of exposure or quantitative measures of cumulative exposure. Similar negative trends were seen with several broad categories of mortality, including all causes. These negative trends are possibly a result of incomplete follow-up that was most severe among workers with the longest tenures. A sizable fraction of deaths occurring during the last 4 years of follow-up evidently were not identified, and there is evidence that follow-up in earlier years was also incomplete. At the very least, problems with the follow-up should be rectified before any conclusions are drawn about the carcinogenicity of DE in this cohort.

Adult↗
PubMed1988

Markers of exposure to diesel exhaust and cigarette smoke in railroad workers.

Diesel exhaust is a complex mixture of combustion gases, vapors and particles, and personal exposure can be estimated indirectly only. Quantitative estimates of exposure were developed for thirteen job groups in a large epidemiologic study of mortality among railroad workers. Three possible markers of exhaust exposure were developed. The first index was the concentration of respirable particles because this was simple and inexpensive to measure precisely. Major positive interference, however, was found from environmental tobacco smoke (ETS) and inorganic respirable particles from other emission sources. Composited job group samples were analyzed for particulate nicotine so the ETS component could be subtracted from the respirable particle concentration. This produced a second exposure index, the adjusted respirable particle concentrations. Since there are nondiesel sources of particles in some work areas, a third marker was sought. Diesel exhaust particles have a relatively high content of dichloromethane extractable matter, but inorganic particles have a low extractable content. Therefore, the air concentration of extractable mass was used as a third marker of diesel exposures. The extractable matter also was corrected for the contribution of ETS. The advantages and limitations of these three markers are of interest. In general, considerable caution should be used in the development and application of markers; their use requires detailed knowledge of the nature and sources of exposure in a given setting.

Air Pollutants, Occupational↗
PubMed2005

Subtraction of 16.67 Hz railroad net interference from the electrocardiogram: application for automatic external defibrillators.

The widespread application of automatic external defibrillators (AEDs) for treating out-of-hospital cardiac arrest incidents and their particular use at railway stations defines the task for 16.67 Hz power line interference elimination from the electrocardiogram (ECG). Although this problem exists only in five European countries, it has to be solved in all AEDs, which must comply with the European standard for medical equipment requirements for interchangeability and compatibility between rail systems. The elimination of the railroad interference requires a specific approach, since its frequency band overlaps with a significant part of the frequencies in the QRS spectra. We present a method based only on one channel ECG signal processing, which effectively subtracts the interference components. The computation procedure is based on simple signal processing tools, which include: (i) bi-directional band-pass filtering (13-23 Hz) of the analyzed ECG segment; (ii) estimation of adequate linearity thresholds; (iii) frequency measurement and calculation of dynamic interference buffer in linear segments and (iv) phase synchronization and subtraction technique in nonlinear segments. The developed method has proved advantageous in providing sufficient quality of the output interference free ECG signal for seven defined arrhythmia types (normal sinus rhythm, normal rhythm, supraventricular tachicardia, slow/rapid ventricular tachycardia, and coarse/fine ventricular fibrillation), and simulated interferences with constant or variable frequencies and amplitudes, which cover the entire amplitude range of the input channel. The procedure is suitable to be embedded in AEDs as a preprocessing branch, which proves reliable for analysis of ECG signals, thus guaranteeing the specified accuracy of the AED automatic rhythm analysis algorithms.

Algorithms↗