X-Ray Diffraction Analysis and Modeling of Strain Induced Thermal Cycling in a Thin Aluminum (011) Bicrystal Film

Heteroepitaxial films of aluminum bicrystals grown on silicon provide a model system in which to study plasticity in polycrystalline metal thin films. For the bicrystal films, dislocations are confined to move on two different slip plane orientations because of the orientation of the crystals on the substrate. In-situ transmission electron microscopy (TEM) observations during thermal cycling have shown two threshold temperatures for dislocation motion on cooling. A simple model uses the resolved shear stress on the possible slip planes to explain the TEM observations. Mechanisms responsible for the dislocation behavior are studied in-situ during thermal cycling between room temperature and 450°C with x-ray diffraction. The strains are determined using a sin2(Ψ) analysis at each temperature. Direct comparisons are made between the TEM observations, the model and x-ray diffraction results.

Gold-Nickel Multilayer Films: Structure-Property Correlations

Gold-nickel multilayer films with periods of 1.2 - 4.6 nm were deposited on silicon substrates by magnetron sputtering, and plan and cross-sectional specimens were examined by transmission electron microscopy. The cross-sectional specimens revealed well-defined layering and columnar growth features that extended through the film thickness. Dark striations extending normal to the layers were attributed to diffraction contrast from defect strain fields. Diffraction patterns showed that the films were highly textured and that short-period films had a single fcc structure, while long-period films separated into three fcc structures. High-resolution images of the layer interfaces showed local regions of epitaxy partitioned by regions of disorder.

Indentation tests using a Nanoindenter, a depth-sensing indentation device, were performed to measure the elastic modulus and hardness of the films. No modulus enhancement was detected, and a small variation in hardness was measured.

Plastic Deformation in Thin Copper Films Determined by X-Ray Micro-Tensile Tests

Plastic deformation in thin copper films has been studied at room temperature. Copper films having a thickness of 1 μm were made by sputtering onto nickel substrates with a Si3N4 underlayer and with or without a Si3N4 caplayer. Deformation experiments were conducted using a special micro-tensile tester built into a θ–θ diffractometer. The problems normally associated with tension tests of free-standing films were avoided by deforming the substrate and film together. In-situ x-ray measurements of the lattice spacings and lattice spacing distributions were used to determine both elastic and plastic strains. The effects of caplayer and annealing temperature on mechanical properties are reported.

In-Situ Tem Investigation During Thermal Cycling of thin Copper Films

In-situ transmission electron microscopy (TEM) was performed to study grain growth and dislocation motion during temperature cycles of Cu films with and without a cap layer. In addition, the substrate curvature method was employed to determine the corresponding stresstemperature curves from room temperature up to 600°C. The results of the in-situ TEM investigations provide insight into the microstructural evolution which occurs during the stress measurements. Grain growth occurred continuously throughout the first heating cycle in both cases. The evolution of dislocation structure observed in TEM supports an explanation of the stress evolution in both capped and uncapped films in terms of dislocation effects.

Microstructure and Mechanical Properties of Thin Al-Si-Ge Films

The mechanical properties are thought to play an important role in the performance of metallization materials for very large scale integration (VLSI) applications. From recent investigations on bulk materials it is known that Al-Si-Ge alloys can be very efficiently strengthened with only a small amount of the alloying elements. These alloys are potential candidates for future metallizations both because Si and Ge are compatible with the existing semiconductor technology, and because the resistivity is expected to be low.

We present the first results of detailed characterizations of Al-Si-Ge thin films as a function of sputter conditions and heat treatments. The microstructure was characterized using x-ray diffraction and transmission electron microscopy. The kinetics of precipitation were studied using resistance measurements. Room temperature hardness was investigated using nanoindentation, and the mechanical properties at temperatures up to 240°C were examined using a substrate curvature method. The correlation between precipitate structure and film properties is discussed.

Micro-Tensile and Fatigue Testing of Copper Thin Films on Substrates

A special micro-tensile tester was used to carry out tensile tests of thin copper films on substrates. The elastic strain in the film was measured in-situ using x-ray diffraction and the total strain with an external strain gage. From the elastic strains the stresses in the films were calculated and stress-strain curves were obtained. It was observed that the flow stress increases with decreasing film thickness. The method was also applied to investigate the mechanical behavior of films under cyclic loading.

Reducing black/white disparity: changes in injury mortality in the 15-24 year age group, United States, 1999-2005

In 1999, the injury death rate for black males aged 15-24 in the USA was 80% greater than for white males: 148.5 vs 82.5/100,000, a difference of 66/100,000. Injury-specific changes between 1999 and 2005 in death rates for the 15-24 age group and in racial disparity were analysed using data from CDC's WISQARS. The gap between black and white all-injury death rates in males was reduced by 24%, to a difference of 50/100,000, largely because of greater decreases in the rates for motor vehicle crashes and firearm suicide in young black men than young white men, and large increases in suicide by suffocation and unintentional poisoning in the latter. Among females, despite a reduction in the black/white gap in firearm homicide rates, the gap between the races in total injury rates changed from a small black excess to a higher rate in young white women, which was due primarily to greater increases in these white women than black women in unintentional poisoning and suicide by suffocation, and greater decreases in black women than white women in firearm suicide.

Injury control: an opportunity for China

Injury control is an important health issue in China, but has been less well explored than in other countries. To encourage health policy makers to give greater attention to injury control, this report highlights the great damage caused by injuries and the neglected status of injury control in China. China's situation and the experiences and lessons from industrialized countries, especially the USA, are summarized. Finally, two opportunities to improve injury control in China are identified: establishment of a mechanism for multi-department coordination and collaboration; and improvement of injury data surveillance.

The SAGA continues: expanding the cellular role of a transcriptional co-activator complex

Throughout the last decade, great advances have been made in our understanding of how DNA-templated cellular processes occur in the native chromatin environment. Proteins that regulate transcription, replication, DNA repair, mitosis and other processes must be targeted to specific regions of the genome and granted access to DNA, which is normally tightly packaged in the higher-order chromatin structure of eukaryotic nuclei. Massive multiprotein complexes have been discovered, which facilitate access to DNA and recruitment of downstream effectors through three distinct mechanisms: chemical modification of histone amino-acid residues, ATP-dependent chromatin remodeling and histone exchange. The yeast Spt-Ada-Gcn5-Acetyl transferase (SAGA) transcriptional co-activator complex regulates numerous cellular processes through coordination of multiple histone post-translational modifications. SAGA is known to generate and interact with a number of histone modifications, including acetylation, methylation, ubiquitylation and phosphorylation. Although best characterized for its role in regulating transcriptional activation, SAGA is also required for optimal transcription elongation, mRNA export and perhaps nucleotide excision repair. Here, we discuss findings from recent years that have elucidated the function of this 1.8-MDa complex in multiple cellular processes, and how misregulation of the homologous complexes in humans may ultimately play a role in development of disease.

Inmate-made weapons in prison facilities: assessing the injury risk

More than 2400 correctional workers in the United States required medical attention in 1999 following assaults by inmates, often with unconventional "homemade" weapons. Little information is available about these weapons. The authors surveyed 101 state prisons for a 12 month period within 2002-03, and 70 responded. A total of 1326 weapons were either confiscated (1086) or used to injure inmates (203) or staff (37). Staff were most often attacked with clubs. The prison store was the most common source of materials used to make confiscated weapons. Issued items were the most common source of materials used to make weapons to injure staff. The injury rate for staff was 1.0/1000 workers per year. The annual cost of injuries for time lost and medical care for staff was estimated at $1,125,000 in these 70 prisons. Results identify materials that should be redesigned to prevent modifications to make weapons. Prison stores and issued items deserve special attention.

Interventions to prevent softball related injuries: a review of the literature

OBJECTIVES

To examine the published evidence on interventions to prevent softball related injuries among adults, and to encourage more epidemiologic research as a foundation for future softball injury prevention efforts.

METHODS

The authors reviewed literature identified from six electronic databases for studies on softball related injuries. The search was limited to studies written in the English language, published between 1970 and 2002, and involving adult populations. Research was excluded that evaluated baseball ("hard ball") related injuries or was aimed at injury treatment. Identified studies were categorized by study design. Intervention/prevention papers were evaluated further and described in detail.

RESULTS

The search strategy identified 39 studies specifically related to softball. Most studies were case reports/case series (n=13) or descriptive studies (n=11); only four were analytic or intervention/prevention studies. Studies collected data in a variety of ways, often without denominator data to permit calculation of injury rates. Studies also did not differentiate between slow or fast pitch softball activities and most did not mention the type of softball that was used.

CONCLUSIONS

Surprisingly few studies exist on interventions to reduce injuries during softball, one of the most popular recreational sports in the US. Of the existing literature, much attention has been on sliding related injuries, which comprise only a segment of softball injuries. Basic epidemiologic studies describing the nature, severity, and risk factors for softball injuries in a variety of populations are needed, followed by additional intervention evaluation studies aimed at modifiable risk factors.

Long-term changes in glutamatergic synaptic transmission in phenylketonuria

The cellular mechanisms that underlie impaired brain function during phenylketonuria (PKU), the most common biochemical cause of mental retardation in humans, remain unclear. Acute application of L-Phe at concentrations observed in the PKU brain depresses glutamatergic synaptic transmission but does not affect GABA receptor activity in cultured neurons. If these depressant effects of L-Phe take place in the PKU brain, then chronic impairment of the glutamate system, which may contribute to impaired brain function, could be detected as changes in postsynaptic glutamate receptors. This hypothesis was tested by using a combination of liquid chromatography-mass spectrometry, patch-clamp, radioligand binding and western blot approaches in forebrain tissue from heterozygous and homozygous (PKU) Pah(enu2) mice. Brain concentrations of L-Phe were nearly six-fold greater in PKU mice (863.12 +/- 17.96 micromol/kg) than in their heterozygous counterparts (149.32 +/- 10.23 micromol/kg). This concentration is significantly higher than the K(B) of 573 microM for L-Phe to compete for N-methyl-D-aspartate (NMDA) receptors. Receptor binding experiments with [3H]MK-801 showed significant up-regulation of NMDA receptor density in PKU mice. Consistent with the depressant effects of L-Phe, expression of NMDA receptor NR2A and (RS)-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor Glu1 and Glu2/3 subunits was significantly increased, whereas expression of the NR2B subunit was decreased. There was no change in GABA alpha1 subunit expression. Given the role of the glutamatergic system in brain development and function, these changes may, at least in part, explain the brain disorders associated with PKU.

Independent predictors of morbidity and mortality in blunt colon trauma

We sought to determine the impact of (1) grade of the colon injury, (2) the formation of an ostomy, and (3) associated injuries on outcomes such as morbidity and mortality after blunt colon injuries. We retrospectively reviewed 16,814 cases of blunt abdominal trauma. Patients with colonic injuries were selected and charts reviewed for demographic, clinical, and outcomes data. Injuries were grouped by the Colon Injury Scale (grades I-V). Independent risk factors of morbidity included spine and lung injuries, as well as increased age. A higher grade of colon injury trended toward a significant association with intra-abdominal complications. Independent risk factors of mortality included liver, heart, and lung injuries, as well as intracerebral blood and female gender. The grade of colon injury, the formation of an ostomy, and management of the colon trauma did not independently predict increased intra-abdominal complications, morbidity, or mortality. These results indicate that patients afflicted with blunt colon trauma experience a high rate of morbidity and mortality from associated injuries and or increased age. Treatment regimens directed at these factors will be most helpful in reducing the high morbidity and mortality after blunt colon trauma. Factors such as ostomy formation and management strategy are not associated with increased morbidity or mortality after blunt colon trauma.

Using multiple information sources to identify opportunities for ergonomic interventions in automotive parts distribution: a case study

An essential activity in any ergonomics program is determining specific work locations and activities where physical demands place workers at increased risk of sustaining an overexertion injury. To do this, safety and health professionals rely on a variety of information sources to identify and prioritize opportunities for ergonomic interventions. As part of a 4-year project to reduce overexertion injuries in the service parts division of a major auto maker, a study was performed in 19 parts distribution centers to evaluate the contributions of the following information sources in identifying specific high-risk work locations and activities: (1) archival medical/injury records, (2) identification of "problem tasks" by plant-based ergonomic committees, (3) facility walk-throughs by experienced ergonomists, and (4) detailed ergonomic job analyses. Archival records were not particularly useful in identifying high-risk activities because essential exposure information (e.g., task, work location) was not documented. Walk-throughs and detailed ergonomic analyses were partially effective in identifying high-risk activities; however, in some cases the observation time was too short to observe peak exposures. Ergonomic committees were generally effective in identifying specific high-risk tasks and work locations. Rankings of "problem tasks" from multiple sites identified consensus division-wide ergonomic concerns. Detailed ergonomic job analyses confirmed that these tasks had high exposure to ergonomic risk factors. This study demonstrated potential pitfalls in relying on a single information source to identify work locations and activities that place workers at increased risk of overexertion injury.

Changes in injury patterns in frontal crashes: preliminary comparisons of drivers of vehicles model years 1993-1997 to drivers of vehicles 1998-2001

Injury severity among drivers of vehicles model year 1993-1997 was compared to that of drivers of vehicles 1998-2001. Data from the National Automotive Sampling System Crashworthiness Data Sets 1993-2000 were used. Differences in injury patterns by model year and gender, type of vehicle, single- or multiple-car crash, severity of crash, safety belt use and airbag deployment were investigated. The 1206 eligible drivers in newer vehicles presented significantly fewer and less severe injuries than their 3827 pre-1998 model year counterparts. This is true for men and women, across severity of crash, and even when confounders are accounted for. The re-design of frontal airbags that occurred around 1998 could be partly responsible for these improvements.

Drinking histories of fatally injured drivers

CONTEXT

About 30% of drivers killed in crashes have high blood alcohol concentrations (BACs) of 0.10+ g/dl. There is a question about whether these drivers primarily are problem drinkers who chronically drink and drive-the so-called hard core drinking drivers.

OBJECTIVE

To investigate drinking histories of fatally injured drivers in relation to their BACs.

DESIGN AND PARTICIPANTS

Retrospective cohort study of 818 fatally injured drivers who were included in the 1993 National Mortality Followback Survey (a national sample of US deaths in which next of kin were interviewed) and whose BACs were recorded by the Fatality Analysis Reporting System, a census of US traffic deaths.

MAIN OUTCOME MEASURE

Problem drinking indicators.

RESULTS

At least one indicator of potential problem drinking, primarily heavy drinking, was reported for 68% of drivers with very high BACs (0.15+ g/dl), 41% with BACs of 0.10-0.14 g/dl, 32% with BACs of 0.01-0.09 g/dl, and 7% with zero BACs. Spouses provided more credible responses than other relatives: they were more likely to report at least occasional drinking and driving among deceased drivers with high BACs. For the most direct signs of problem drinking (described as a problem drinker during the last month of life or frequently driving after having five or more drinks), spousal reports suggested the prevalence of problem drinking among drivers with very high BACs was 22% (having both indicators), 32% (frequently driving after having five or more drinks), 44% (described as problem drinker), or 57% (having either indicator).

CONCLUSIONS

Drivers with BACs of 0.10+ g/dl were far more likely than sober drivers to be described as having markers of problem drinking. However, many did not have indicators suggestive of problem drinking. In addition to programs focused on repeat offenders or problem drinkers, countermeasures such as sobriety checkpoints that target a broader spectrum of drinking drivers are appropriate.

General aviation crashes involving military personnel as pilots

BACKGROUND

Injuries sustained in off-duty activities are a major cause of mortality and morbidity among military personnel. Reducing these off-duty fatalities is a continuing priority of the military.

METHODS

General aviation crashes recorded by the National Transportation Safety Board between 1983 and 1998 were analyzed for military pilots (n = 205) and other military personnel (n = 185), and compared with all other general aviation crashes (n = 32,807) to identify differences in the crash circumstances and sustained injury severities.

RESULTS

During the 16-yr study period, a total of 45 military pilots and 52 other military personnel were fatally injured while flying general aviation flights. Military pilots who were involved in general aviation crashes were more likely to have advanced licenses and higher total flight times when compared with other military personnel and civilian pilots (p < 0.05). Among the three groups of pilots, other military personnel had the least flying time and the largest percentage of student/private licenses. Military personnel had significantly less time in type in the 90-d and 30-d periods preceding the crash compared with civilians (p < 0.05). Shoulder restraint usage was associated with less severe injuries for all groups. We estimate that general aviation deaths have cost the military at least $405 million since 1983.

CONCLUSIONS

General aviation crashes are a costly source of mortality and morbidity for military personnel, particularly military pilots. Interventions aimed at improving safety of military personnel in the general aviation setting warrant special consideration.

Mersilene mesh sling: short- and long-term clinical and urodynamic outcomes

OBJECTIVE

We sought to determine the long-term efficacy, safety, and urodynamic effects of the Mersilene mesh suburethral sling in treating complicated forms of genuine stress incontinence.

STUDY DESIGN

Two hundred women diagnosed with genuine stress incontinence, complicated by recurrence, intrinsic sphincter deficiency, or chronically increased intraabdominal pressure underwent a suburethral mesh sling procedure (Mersilene; Ethicon Inc, Somerville, NJ). They were monitored with yearly clinical examinations plus short- and long-term postoperative urodynamic evaluations; statistical analysis was carried out by use of the Friedman 2-way analysis by rank, Fischer-Freeman-Halton exact testing, analysis of variance for repeated measures, Wilcoxon, exact Mann-Whitney U test, and Bonferroni paired t test. Of 176 patients who were 5 months or more postop, 127 (72%) had preoperative and short-term postoperative urodynamic evaluations (range 5 to 23 months, mean 12.6 months). Fifty-two of 117 women who were more than 19 months postop (44%) completed preoperative and long-term postoperative urodynamic evaluations at a mean of 63 months (range 20 to 107). One hundred thirty-six of 176 patients (77%) who were more than 4 months postop had a short- and/or long- term postoperative urodynamic evaluation (range 5 to 107 months, mean 30 months).

RESULTS

Objective cure rate by stress test was 93% (126 of 136 patients) at a mean of 30 months follow-up. The long-term objective cure rate was 94% (49 of 52). Subjectively, the short- and long-term cure rates were 95.3% and 90.4%, respectively. The cotton swab angle deflection decreased by a mean of 54 degrees at 1 year and 50 degrees at 5 years. Of the 10 failures, the mean preoperative cotton swab straining angle was 19.6 degrees, with 6 being < 30 degrees. Nineteen patients had a negative preoperative cotton swab angle test result (mean straining angle 15 degrees before operation, -6 degrees after operation) and a long-term cure rate of 67%. The objective cure rate in patients with positive cotton swab angle results monitored long term (mean 62 months) was 100% (41 of 41). The postvoid residual increased by a mean of 25 mL short term and 10 mL long term. Thirty-eight patients (19%) had a total of 43 complications. Seven patients (3.5%) had long-term retention. De novo detrusor instability occurred in 12 patients (8.8%), although it was cured in 6 (4.4%). Eight patients (4%) had vaginal or inguinal sling erosion and were healed after revision. Delayed healing at the vaginal sling site responded completely to estrogen cream in two (1%) patients. Five women had treatable vaginal stenosis, 5 had a local inguinal collection/infection unrelated to the mesh, and 3 required a 2-unit transfusion of packed red blood cells. One patient each had an entrapped nerve released, a cystotomy repaired, or experienced thigh numbness or groin pain.

CONCLUSIONS

The suburethral Mersilene mesh sling has a very high long-term objective and subjective cure rate in the treatment of complicated forms of genuine stress incontinence. Frequent complications do occur but are remediable. The 33% failure rate among patients with a preoperative negative cotton swab angle test result and the very low cotton swab straining angle among the 7% who had sling failures further confirms the widely held belief that sling urethropexy in the absence of hypermobility lacks efficacy.

Novel short-acting A2A adenosine receptor agonists for coronary vasodilation: inverse relationship between affinity and duration of action of A2A agonists

Several potent and selective A2A adenosine receptor agonists are currently available. These compounds have a high affinity for the A2A receptor and a long duration of action. However, in situations where a short duration of action is desired, currently available A2A receptor agonists are less than ideal. From a series of recently synthesized A2A receptor agonists, two agonists (CVT-3146 and CVT-3033) with low affinity were selected for further characterization as selective and short-acting coronary vasodilators. Both compounds were selective for the A2A adenosine receptor (AdoR) versus the A1, A2B, and A3AdoR in binding and functional studies. CVT-3146 and CVT-3033 appeared to be weak partial agonists to cause cAMP accumulation in PC12 cells, but were full and potent agonists to cause coronary vasodilation, a response that has a very large A2A receptor reserve. However, the durations of action of CVT-3146 and CVT-3033 were remarkably shorter than those of the high-affinity agonists CGS21680 or WRC0470, presumably due to the relative lower affinity of CVT-3146 and CVT-3033 for the A2A receptor. Indeed, an inverse relationship was found between the affinity of the various agonists for the A2A receptor and the duration of their actions. These data indicate that low-affinity agonists can produce a response that is of equivalent magnitude but more rapid in termination than that caused by a high-affinity agonist. Hence, the low-affinity A2A agonists CVT-3146 and CVT-3033 may prove to be superior to currently available high-affinity agonists as coronary vasodilators during myocardial imaging with radionuclide agents.

Potential benefits of restrictions on the transport of teenage passengers by 16 and 17 year old drivers

OBJECTIVES

The presence of passengers is associated with fatal motor vehicle crashes of teenage drivers. A restriction against newly licensed teenage drivers carrying passengers has been included in some, but not all, graduated licensing systems. The purpose of this study was to predict the net effects on all types of road users, including vehicle occupants and non-occupants, of possible prohibitions against 16-17 year old drivers carrying passengers.

METHODS

Two national datasets, a census of fatal crashes and a sample of trips in the United States, were used to compute 1995 road user death rates. Potential effects of restrictions on drivers ages 16-17 carrying passengers younger than 20 were estimated, based on road user death rates and potential choices made by passengers who would have traveled with 16-17 year old drivers if there were no restrictions.

RESULTS

There were 1,181 road user deaths in 1995 involving drivers ages 16-17 whose passengers were all younger than age 20. The predicted number of lives in the United States that would be saved annually ranges from 83 to 493 (corresponding to reductions of 7-42% in road user deaths) for drivers ages 16 and 17 combined. Similar percentages of reductions (8-44%) were predicted solely for 16 year old drivers. Assuming passenger restrictions would apply to all 16 year old drivers and at least one third of 17 year old drivers, an estimated 60-344 fewer deaths per year may occur if restrictions are mandated.

CONCLUSIONS

Restrictions on carrying passengers younger than 20 should be considered for inclusion in graduated licensing systems. Even if fewer than half the drivers obey the restrictions, a substantial reduction in road user deaths would be expected. Further evaluation based on real world experience is needed to confirm their efficacy.

Secular trends of motor vehicle mortality in the United States, 1910-1994

To examine the secular trends of mortality from motor vehicle crashes, the authors compiled annual population and mortality data for the United States from 1910 to 1994 and performed an age-period-cohort analysis through graphical presentation, median polish, and Poisson regression modeling. During the 85-year study period, death rates from motor vehicle crashes showed two peaks, first in 1935-39 and then in 1965-69. Age and period effects accounted for 94% of the variation in motor vehicle mortality in men and 84% of the variation in women. Age patterns of motor vehicle mortality varied greatly with birth cohorts: for those who were born before 1910, death rates increased with age; for those born after 1910, death rates peaked at age 20-24 years for men and at age 15-19 years for women. A crossover characterized by a downward trend in death rates among the elderly and an upward trend among adolescents and young adults was observed in both sexes. The complex age, period, and cohort patterns of motor vehicle mortality are likely to have been shaped by changes in traffic patterns and driver behavior, and by improvements in safety design and emergency medical service systems.

Characteristics of general aviation crashes involving mature male and female pilots

BACKGROUND

General aviation crashes in the United States were analyzed to identify differences between male and female pilots in the circumstances of their crashes and the types of pilot errors involved.

METHODS

All 144 female pilots who were born between 1933 and 1942 and who were involved in general aviation crashes between 1983 and 1997 were matched 1:2 with 287 male pilots by age within 2 yr, medical certificate and pilot certificate, state or region of crash, and year of crash.

RESULTS

Mechanical failure, gear up landings, improper IFR approaches, and collisions with wires or poles were more common in crashes of male pilots. Loss of control on landing/takeoff was more common in crashes of female pilots. Mishandling aircraft kinetics was the most common error of pilots of both genders and was noted more often in female pilots' crashes (81% vs. 48%) (p < 0.001). Males' crashes were more likely to involve flawed decisions (29% vs. 19% of females' crashes) (p = 0.027) or inattention (32% vs. 19%) (p = 0.004). Older pilots made fewer errors: among males age 55-63, 26% of crashes were without obvious pilot error compared with only 7% at age 40-49 (p = 0.003).

CONCLUSION

There are large gender differences in the types of pilot error involved in general aviation crashes. Mishandling aircraft kinetics, poor decision making, and inattention are the most common pilot errors and merit increased attention in pilot training.

Evaluation of linear and nonlinear tomosynthetic reconstruction methods in digital mammography

RATIONALE AND OBJECTIVES

The purpose of this study was to comparatively evaluate digital planar mammography and both linear and nonlinear tomosynthetic reconstruction methods.

MATERIALS AND METHODS

A "disk" (ie, target) identification study was conducted to compare planar and reconstruction methods. Projective data using a composite phantom with circular disks were acquired in both planar and tomographic modes by using a full-field, digital mammographic system. Two-dimensional projections were reconstructed with both linear (ie, backprojection) and nonlinear (ie, maximization and minimization) tuned-aperture computed tomographic (TACT) methods to produce three-dimensional data sets. Four board-certified radiologists and one 4th-year radiology resident participated as observers. All images were compared by these observers in terms of the number of disks identified.

RESULTS

Significant differences (P < .05, Bonferroni adjusted) were observed between all reconstruction and planar methods. No significant difference, however, was observed between the planar methods, and only a marginally significant difference (P < .054, Bonferroni adjusted) was observed between TACT-backprojection and TACT-minimization.

CONCLUSION

A combination of linear and nonlinear reconstruction schemes may have potential implications in terms of enhancing image visualization to provide radiologists with valuable diagnostic information.

Use of alcohol as a risk factor for bicycling injury

CONTEXT

Bicycling is one of the leading causes of recreational injuries. Elevated blood alcohol concentrations (BACs) are found in about one third of fatally injured bicyclists aged 15 years or older.

OBJECTIVE

To assess the relative risk of fatal and serious bicycling injury according to BAC.

DESIGN

Matched case-control study.

SETTING AND SUBJECTS

Bicyclists aged 15 years or older who were fatally or seriously injured while riding a bicycle during the day in Maryland in 1985-1997 (cases, n = 124) and bicyclists aged 15 years or older who were interviewed and given a breath test for estimated BAC during roadside surveys that took place in June 1996 through May 1998 at the same site, time of day, day of week, and month of year in which a case bicyclist was injured (controls, n = 342).

MAIN OUTCOME MEASURE

Odds ratio of bicycling injury according to estimated BAC.

RESULTS

An estimated positive BAC (>/=0.02 g/dL) was detected in 12.9% of the case bicyclists (23.5% of the 34 fatally injured and 8.9% of the 90 seriously injured) compared with 2.9% of the control bicyclists (P<.001). Relative to an estimated BAC of less than 0.02 g/dL, the adjusted odds ratio of bicycling injury was 5.6 (95% confidence interval [CI], 2.2-14.0) for a BAC of 0.02 g/dL or higher and was 20.2 (95% CI, 4.2-96.3) for a BAC of 0.08 g/dL or higher. Rates of helmet use at the time of injury or interview were 5% and 35%, respectively, for those with and without a positive BAC (P =.007).

CONCLUSION

Alcohol use while bicycle riding is associated with a substantially increased risk of fatal or serious injury.

Factors associated with pilot error in aviation crashes

BACKGROUND

The importance of pilot error in aviation crashes has long been recognized. However, understanding and preventing pilot error remains the foremost challenge in aviation safety.

OBJECTIVE

This study aims to identify pilot characteristics and crash circumstances that are associated with the presence of pilot error in a large sample of aviation crashes.

METHODS

Different data files compiled by the National Transportation Safety Board for 329 major airline crashes, 1,627 commuter/air taxi crashes, and 27,935 general aviation crashes for the years 1983-96 were merged; and the presence of pilot error was analyzed in relation to variables indicating the characteristics of the pilot-in-command, crash circumstance, and aircraft. Multivariate logistic regression modeling was performed to assess the associations of individual variables with the likelihood of pilot error given a crash.

RESULTS

Pilot error was a probable cause in 38% of the major airline crashes, 74% of the commuter/air taxi crashes, and 85% of the general aviation crashes. Among the factors examined, instrument meteorological condition and on-airport location were each associated with a significantly increased odds of pilot error. The likelihood of pilot error decreased as pilot certificate rating increased in commuter/air taxi and general aviation crashes. Neither pilot age nor gender was independently associated with the odds of pilot error. With adjustment for pilot characteristics and crash circumstances, flight experience as measured in total flight time showed a significant protective effect on pilot error in general aviation crashes.

CONCLUSIONS

The prevalence and correlates of pilot error in aviation crashes vary with the type of flight operations. Adverse weather is consistently associated with a significantly elevated likelihood of pilot error, possibly due to increased performance demand.

Fluorosulfonyl-substituted xanthines as selective irreversible antagonists for the A(1)-adenosine receptor

FSCPX (1) has been reported to be a potent, selective, and irreversible antagonist for the A(1)-adenosine receptor (AR). To obtain an irreversible A(1)AR antagonist with potentially better stability and to further elucidate the effects of linker structure on the pharmacological characteristics, several new analogues were targeted in which the labile ester linkage of 1 was replaced by more stable functionalities. In particular, alkyl and amide linkers between the xanthine pharmacophore and the reactive 4-fluorosulfonylphenyl group were explored. The data showed that the chemical composition of the linker affects the affinity and apparent irreversible binding to the A(1)AR. Overall, compound 23b appeared to have the most advantageous characteristics as a potential irreversible ligand for the A(1)AR. These include relatively high affinity for the A(1)AR as compared to the A(2A)AR, concentration-dependent and selective apparent irreversible binding to the A(1)AR, and ease of removal of unbound ligand from biological membranes. These properties indicate that 23b has the potential to be a useful tool for further study of the structure and function of the A(1)AR.

Comparison of tomosynthesis methods used with digital mammography

RATIONALE AND OBJECTIVES

The authors performed this study to investigate the potential applicability of tomosynthesis to digital mammography. Four methods of tomosynthesis-tuned aperture computed tomography (TACT)-backprojection, TACT-iterative restoration, iterative reconstruction with expectation maximization, and Bayesian smoothing-were compared to planar mammography and analyzed in terms of their contrast-detail characteristics. Specific comparisons between the tomosynthesis methods were not attempted in this study.

MATERIALS AND METHODS

A full-field, amorphous, silicon-based, flat-panel digital mammographic system was used to obtain planar and tomosynthesis projection images. A composite tomosynthesis phantom with a centrally located contrast-detail insert was used as the object of interest. The total exposure for multiple views with tomosynthesis was always equal to or less than that for the planar technique. Algorithms were used to reconstruct the object from the acquired projections.

RESULTS

Threshold contrast characteristics with all tomosynthesis reconstruction methods were significantly better than those with planar mammography, even when planar mammography was performed at more than twice the exposure level. Reduction of out-of-plane structural components was observed in all the tomosynthesis methods analyzed.

CONCLUSION

The contrast-detail trends of all the tomosynthesis methods analyzed in this study were better than those of planar mammography. Further optimization of the algorithms could lead to better image reconstruction, which would improve visualization of valuable diagnostic information.

Differential A(1)-adenosine receptor reserve for inhibition of cyclic AMP accumulation and G-protein activation in DDT(1) MF-2 cells

1. The A(1)-adenosine receptor (A(1)AdoR) reserve for N(6)-cyclopentyladenosine (CPA) mediated inhibition of (-)isoprenaline stimulated cyclic AMP accumulation and stimulation of [(35)S]-guanosine-5'-O-(thiotriphosphate) (GTPgammaS) binding, a measure of guanine nucleotide binding protein (G-protein) activation, was determined in DDT(1) MF-2 cells. 2. Inactivation of the A(1)AdoRs with the chemoreactive ligand 8-cyclopentyl-3-[3-[[4-(fluorosulphonyl)benzoyl]oxy]propyl]-1-p ropylx anthine (FSCPX) caused a progressive rightward shift of the concentration-response curves for CPA to inhibit cyclic AMP accumulation, with a maximum of 10 fold increase in the EC(50) value. In contrast, inactivation of A(1)AdoR's caused only a 1.7 fold rightward shift in the CPA concentration-response for stimulation of [(35)S]-GTPgammaS binding. 3. The A(1)AdoR occupancy-response relationship for CPA inhibition of cyclic AMP accumulation was hyperbolic with 43% receptor occupancy required to elicit the maximal response, i.e. a 57% A(1)AdoR reserve. In contrast, the A(1)AdoR occupancy-response relationship for CPA mediated stimulation of [(35)S]-GTPgammaS binding was linear indicating little or no receptor reserve for G-protein activation. The relationship between CPA stimulation of [(35)S]-GTPgammaS binding and cyclic AMP inhibition was also hyperbolic with 44% G-protein activation sufficient to cause maximal inhibition. 4. The data suggest that the A(1)AdoR reserve for CPA mediated inhibition of cyclic AMP accumulation occurs at the level of G-protein interaction with adenylyl cyclase. However, each A(1)AdoR appears to activate a constant fraction of the total G-protein population suggesting signal amplification at the receptor-G-protein level which may also contribute to the receptor reserve for CPA.

Alcohol use in relation to driving records among injured bicyclists

To prevent alcohol-related occupational mishaps, employers often conduct background checks on prospective employees for history of driving while intoxicated (DWI) and driving under the influence of alcohol (DUI) to screen out candidates with drinking problems. Few studies, however, have examined the pervasive nature of drinking behavior across activity domains. Based on trauma registry data, we constructed a historical cohort of 120 Maryland residents ages 18 years or older who were injured while riding a bicycle between 1990 and 1997. Driving records for the 120 bicyclists for the 3 years between May 6, 1995 and May 5, 1998 were obtained from the state motor vehicle administration and were analyzed in relation to BAC-positive status at the time of injury. Bicyclists with positive BACs at the time of admission to the trauma center were significantly more likely than those with negative BACs to have a record of license suspension/revocation (52% vs 14%, P < 0.01) and to have DWI/DUI convictions (30% vs 3%, P < 0.01). Despite the modest sample size, this study provides compelling evidence of the pervasive nature of risky drinking between bicycling and driving activities.

Tandem ireland-claisen rearrangement ring-closing alkene metathesis in the construction of bicyclic beta-lactam carboxylic esters

4-Alkenyl-2-azetidinone systems were converted to the corresponding ethyl 2-¿4-alkenyl-2-oxo-1-azetidinyl-4-pentenoates. In addition, 4-(2-propenyl-1-oxy)-, 4-(2-propenyl-1-thio)-, 4-¿N-(2-propenyl)-(4-toluenesulfonyl)- and (3S, 4R)-4-(2-propenyl)-3-¿(1R)-1-(tert-butyldimethylsilyloxy)ethyl-++ +azeti din-2-one were converted into beta-lactam dienes via sequential N-alkylation, Ireland-Claisen ester enolate rearrangement and esterification. Ring-closing metathesis using the Schrock ¿(CF(3))(2)MeCO(2)Mo(=CHCMe(2)Ph)(=NC(6)H(3)-2,6-iso-Pr(2)) (1) or Grubbs Cl(2)(Cy(3)P)(2)Ru=CHPh (2) carbenes gave a series of ¿5.2.0 and ¿6.2.0 bicycles. Subsequent elaboration of the analogous (2R,7R, 8S)-tert-butyl 8-¿(1R)-(tert-butyldimethylsilyloxy)ethyl-1-aza-9-oxobicyclo++ +¿5.2. 0non-4-ene-2-carboxylate (15), via selenation and desilylation, gave (+)-(2S,7R,8S)-tert-butyl 8-¿(1R)-hydroxyethyl-1-aza-9-oxobicyclo¿5.2.0nona-2, 4-diene-2-carboxylate (18), a novel type of bicyclic beta-lactam. Diels-Alder cycloaddition further afforded tetracyclic systems exemplified by tert-butyl (1R,4S,5R,7S)-4-¿(1R)-1-hydroxyethyl-3,9, 11-trioxo-10-phenyl-2,8,10,12-tetraazatetracyclo¿5.5.2.0.(2, 5)0(8, 12)tetradec-13-ene-1-carboxylate (19).

Sports and physical training injury hospitalizations in the army

INTRODUCTION

Injuries are the leading health problem in the military services. Sports and physical training activities are an area in which a substantial number of injuries can occur. Although athletic injuries are not often investigated in military populations, the Armed Forces database provides a unique opportunity to investigate sports injuries.

METHODS

An Army database of all hospital admissions for active duty Army personnel in the 1989-1994 period was used to study injuries resulting from sports and Army physical training.

RESULTS

For the 6-year time period reviewed, there were 13,861 hospital admissions for injuries resulting from sports or Army physical training: 94% (13,020) of these admissions were men and 6% (841) were women. The rates of sports injuries were 38 and 18 per 10,000 person-years for men and women, respectively. Sports injuries accounted for an average of 29,435 lost duty days each year: Men lost an average of 13 days per injury and women lost an average of 11 days per injury. Acute musculoskeletal injuries in the categories of fractures, sprains/strains, and dislocations accounted for 82% of all injuries. The knee was the most often injured body area in both genders, with the anterior cruciate ligament (ACL) identified as the most frequently injured body part overall. The top seven injuries were virtually identical for men and women, with only slight variations in order. Although the rates of all hospitalized sports injuries were higher for men than women, women had a higher proportion of ACL injuries from basketball and softball, ankle fractures from softball and head injuries from basketball. For men, football and basketball contributed to the highest rates of injuries. The highest injury rates for women were from Army physical training and basketball. For both men and women, Army physical training was the leading cause of lumbosacral strains.

CONCLUSIONS

Sports and Army physical training injuries account for a significant amount of lost duty time and impact military readiness.

Carrying passengers as a risk factor for crashes fatal to 16- and 17-year-old drivers

CONTEXT

Injuries from motor vehicle crashes are the leading cause of death among teenagers. Carrying passengers has been identified as a possible risk factor for these crashes.

OBJECTIVE

To determine whether the presence of passengers is associated with an increased risk of crashes fatal to 16- and 17-year-old drivers and whether the risk varies by time of day and age and sex of drivers and passengers. DESIGN AND SETTING INCIDENCE: study of data from the Fatality Analysis Reporting System and General Estimates System (1992-1997), as well as the Nationwide Personal Transportation Survey (1995).

SUBJECTS

Drivers aged 16 and 17 years who drove passenger cars, vans, or pickup trucks.

MAIN OUTCOME MEASURE

Driver deaths per 10 million trips by number of passengers, driver age and sex, and time of day; and driver deaths per 1000 crashes by passenger age and sex.

RESULTS

Compared with drivers of the same age without passengers, the relative risk of death per 10 million trips was 1.39 (95% confidence interval [CI], 1.24-1.55) for 16-year-old drivers with 1 passenger, 1.86 (95% CI, 1.56-2.20) for those with 2 passengers, and 2.82 (95% CI, 2.27-3.50) for those with 3 or more passengers. The relative risk of death was 1.48 (95% CI, 1.35-1.62) for 17-year-old drivers with 1 passenger, 2.58 (95% CI, 2.24-2.95) for those with 2 passengers, and 3.07 (95% CI, 2.50-3.77) for those with 3 or more passengers. The risk of death increased significantly for drivers transporting passengers irrespective of the time of day or sex of the driver, although male drivers were at greater risk. Driver deaths per 1000 crashes increased for 16- and 17-year-olds transporting male passengers or passengers younger than 30 years.

CONCLUSION

Our data indicate that the risk of fatal injury for a 16- or 17-year-old driver increases with the number of passengers. This result supports inclusion of restrictions on carrying passengers in graduated licensing systems for young drivers.

Adolescent patients--healthy or hurting? Missed opportunities to screen for suicide risk in the primary care setting

CONTEXT

Adolescent suicide rates have increased dramatically in recent decades. Suicide is the third leading cause of mortality among persons aged 10 to 19 years. Several official guidelines recommend screening for suicidal behavior in the primary care setting.

OBJECTIVES

To determine the prevalence of adolescent suicidal behavior known to primary care providers and to determine the knowledge, attitudes, and practice of primary care physicians in Maryland regarding screening for risk factors for adolescent suicide.

DESIGN

Cross-sectional study using mailed survey.

SETTING

Maryland from May to July 1995.

PARTICIPANTS

All pediatrician (n = 816) and family physician (n = 592) members of the state chapter of the American Academy of Pediatrics and the American Academy of Family Physicians, respectively, who were actively providing ambulatory care.

MAIN OUTCOME MEASURES

Adolescent suicidal behavior known to primary care providers and predictors of routine screening for risk factors for adolescent suicide.

RESULTS

The response rate was 66%. Three hundred twenty-eight physicians (47%) reported that 1 or more adolescent patients attempted suicide in the previous year, but only 158 (23%) either frequently or always screened adolescent patients for suicide risk factors. Significant factors correlating with routine screening for suicide risk factors included frequently or always counseling about the safer storage of firearms in the home (odds ratio [OR], 5.3; 95% confidence interval [CI], 2.8-10.2); agreeing or strongly agreeing that they were sufficiently trained and knew how to screen for risk factors (OR, 3.2; 95%/CI, 1.7-6.3); agreeing or strongly agreeing that they had enough time during the well visit to screen for mental health problems (OR, 2.9: 95% CI, 1.6-5.3); frequently or always counseling about child passenger safety (OR, 2.7; 95% CI, 1.6-4.7); spending more than 5 minutes in anticipatory guidance during the well visit (OR, 2.7: 95% CI, 1.5-4.6); practicing in an urban setting (OR, 2.3; 95)% CI, 1.2-4.7); agreeing or strongly agreeing that physicians can be effective in preventing adolescent suicide and that what they do during an office visit may help prevent adolescent suicide (OR, 2.0; 95% CI, 1.2-3.4); and female sex (OR. 1.9; 95% CI, 1.1-3.2).

CONCLUSION

Despite the substantial proportion of primary care providers who encountered suicidal adolescent patients, most providers still do not routinely screen their patients for suicidality or associated risk factors. More training is needed and desired by the survey respondents. Patient confidentiality issues must be addressed. Development and widespread use of a short, easily administered, reliable, and valid screening tool are recommended to help busy clinicians obtain more complete information during all visits.

A case-control study of forklift and other powered industrial vehicle incidents

BACKGROUND

This study examined risk factors associated with forklift and other powered industrial vehicle (PIV) collision injuries with an emphasis on the design of factory traffic systems, the loading and safety features of PIVs, and the characteristics of the drivers.

METHODS

A case-control study examined risk factors for circumstances of injury-producing PIV incidents at eight automotive manufacturing plants between July 1992 and March 1995. A computerized safety and health surveillance system identified 171 incidents where a PIV (forklift 70%, personnel carriers 15%, other 15%) was involved in a collision incident. Site visits were conducted to collect data regarding the factory environment at the collision site, the PIVs involved in the incidents, and driver characteristics. These data were compared with information collected from a random sample of comparison worksites, PIVs, and PIV drivers who had not been involved in a PIV-related incident in the prior 3 years.

RESULTS

In half of the cases (86 of 171), an employee (pedestrian) was struck by a PIV or an object being carried by the PIV. The presence of an obstruction that restricted the aisle width increased the odds of a collision incident 1.89 times (95% CI=1.22, 2.86). The presence of overhead mirrors at intersections and blind corners with limited visibility reduced the odds of a PIV collision incident by a third (OR=0.33, 95% CI=0.16, 0.68). When carrying a load, the odds of a PIV being involved in a collision was 1.58 (95% CI=1.03, 2.41) times greater than an unloaded one.

CONCLUSIONS

Changes in the factory environment, vehicle safety features, and driver and pedestrian training are suggested to reduce the risk of PIV incidents. Am. J. Ind. Med. 36:522-531, 1999. Published 1999 Wiley-Liss, Inc.

Injuries related to forklifts and other powered industrial vehicles in automobile manufacturing

BACKGROUND

The Bureau of Labor Statistics (BLS), Census of Fatal Occupational Injuries, estimates that approximately 100 workers are fatally injured each year in forklift and other powered industrial vehicle (PIV) incidents, and an estimated 34,000 work-related injuries involving forklifts are treated in U.S. emergency rooms each year.

METHODS

This paper presents a descriptive analysis of 916 incidents involving forklifts and other PIVs that occurred in 54 plants operated by a major U.S. automobile manufacturer over a 3-year period. The injury data were obtained from a company-wide occupational injury and illness surveillance system which was implemented in 1989.

RESULTS

The 916 PIV-related incidents resulted in 3 fatalities and 913 nonfatal injuries. The most common incident involved pedestrians (35%) who were struck by a PIV, or the load being carried by a PIV, or a rack or bin that had been struck by a PIV. Of the 913 nonfatal injuries, 41% resulted in an employee missing work and incurred a total of 22,730 lost workdays, an average of 61 days per lost workday incident.

CONCLUSIONS

Recommendations are presented to reduce the risk of injury, for example by separating PIV and pedestrian traffic, restricting the use of forklifts in an area where a large number of pedestrians travel and improving the training of all personnel who drive PIVs. Am. J. Ind. Med. 36:513-521, 1999. Published 1999 Wiley-Liss, Inc.

Back injury in municipal workers: a case-control study

OBJECTIVES

The purpose of this study was to identify factors associated with acute low back injury among municipal employees of a large city.

METHODS

For each of 200 injured case patients, 2 coworker controls were randomly selected, the first matched on gender, job, and department and the second matched on gender and job classification. In-person interviews were conducted to collect data on demographics, work history, work characteristics, work injuries, back pain, psychosocial and work organization, health behaviors, and anthropometric and ergonomic factors related to the job. Psychosocial work organization variables were examined with factor analysis techniques; an aggregate value for job strain was entered into the final model. Risk factors were examined via multivariate logistic regression techniques.

RESULTS

High job strain was the most important factor affecting back injury (odds ratio [OR] = 2.12, 95% confidence interval [CI] = 1.28, 3.52), and it showed a significant dose-response effect. Body mass index (OR = 1.54, 95% CI = 1.08, 2.18) and a work movement index (twisting, extended reaching, and stooping) (OR = 1.42, 95% CI = 0.97, 2.08) were also significant factors.

CONCLUSIONS

Results suggest that increasing workers' control over their jobs reduces levels of job strain. Ergonomic strategies and worksite health promotion may help reduce other risk factors.

The carnage wrought by major economic change: ecological study of traffic related mortality and the reunification of Germany

OBJECTIVE

To document the effects of sudden economic change on death rates for occupants of cars in the former German Democratic Republic (East Germany).

DESIGN

Ecological time series study of East Germany in comparison with the former Federal Republic of Germany (West Germany) before and after reunification in 1990.

SETTING

East and West Germany from 1985 to 1996.

SUBJECTS

Populations of East and West Germany between 1985 and 1996.

MAIN OUTCOME MEASURES

Death rates for occupants of cars.

RESULTS

After the reunification of Germany, East Germany experienced a sudden, temporary affluence and a concomitant fourfold increase in death rates for car occupants between 1989 and 1991. Although death rates increased in all age groups, young adults (aged 18-24) were most affected. The death rate per 100 000 population for those aged 18-20 years increased 11-fold between 1989 and 1991; for those aged 21-24 years the increase was eightfold.

CONCLUSION

A tragic consequence of the reunification of Germany was a dramatic increase in the death rate for car occupants. Sudden economic change and availability of cars resulted in both a rise in vehicle ownership and an increase in the number of inexperienced drivers on roads that were ill prepared for the increased traffic. The lesson learnt from Germany is that during times of economic change and modernisation, measures to prevent the predictable injury deaths that will result need to be considered.

Homebuilt aircraft crashes

BACKGROUND

While the number of general aviation crashes has decreased over the 5 yr prior to 1993, the total number of homebuilt aircraft crashes has increased by nearly 25%. Research was undertaken to analyze these crashes and identify causal factors or unique problems associated with homebuilt aircraft.

METHODS

Some 200 National Transportation Safety Board computer records and two-page descriptive briefs were analyzed for homebuilt aircraft crashes during 1993. Using descriptive epidemiology, variables were looked at in detail and comparisons were made with general aviation crashes during the-same year.

RESULTS

Despite accounting for only 3% of all hours flown in general aviation certified aircraft for 1993, homebuilt aircraft accounted for 10% of the crashes and experienced a higher fatal crash rate. Crashes due to mechanical failure and crashes on takeoff and climb were more common in homebuilt aircraft as compared with general aviation. Other significant causal factors for homebuilt aircraft crashes included: minimal flight time in type specific aircraft, improper maintenance and improper design or assembly.

CONCLUSIONS

Greater emphasis needs to be placed on educating homebuilt aircraft owners in the importance of following Federal Aviation Administration guidelines for certification and air worthiness testing. Understanding the aircraft's specifications and design limitations prior to the initial flight and properly maintaining the aircraft should also help to reverse the trend in the number of these crashes and subsequent lives lost. A system for assuring that all home-built aircraft are certified and more accurate reporting of flight hours are needed for accurate tracking of homebuilt aircraft crash rates.

Adenosine receptor ligands with oxygenated N6-substituents

A number of novel adenosine analogs bearing oxygenated substituents in the N6-position have been prepared and evaluated as A1 adenosine agonists. Improved conditions for the synthesis of N6-substituted adenosines and a new one pot procedure for the synthesis of 2-amino-7-oxabicyclo[2.2.1]hept-5-ene are also reported.

Can injurious falls be prevented?

The resident population in facilities changes over time. In some facilities there may be a large turnover of residents; in other types of facilities some residents will remain, age in place and become more frail. In addition, some medical conditions and intrinsic factors cannot be changed. Since there is not a single set of factors that can guide nursing staff as to which residents are at high risk for serious injurious falls, taking some general protective actions is appropriate. Some examples are: Monitoring the use of psychotropic medications through the MDS. Assessing the environment to determine potential risks that can be minimized or abolished. Using hip protectors to reduce hip fractures among elderly residents who fall.

Correlates of pilot fatality in general aviation crashes

BACKGROUND

General aviation accounts for the majority of aviation crashes and casualties in the United States, and general aviation safety has not improved in the past decade.

OBJECTIVE

This study identifies factors associated with pilot fatality in general aviation crashes.

METHODS

We analyzed the National Transportation Safety Board's Factual Reports for all airplane and helicopter crashes of general aviation flights that occurred in North Carolina and Maryland during 1985 through 1994. Surviving pilots were compared with fatally injured pilots in relation to crash circumstances, and pilot and aircraft characteristics, at bivariate level and multivariate level.

RESULTS

A total of 667 crashes resulted in 276 deaths and 368 injuries during the 10-yr period in the two states. Of the pilots-in-command involved in these crashes, 146 (22%) died. The case fatality rate for pilots was significantly higher in crashes that occurred between 6 p.m. and 5 a.m. (34%), away from airports (36%), with aircraft fire (69%), or in instrument meteorological weather conditions (IMC) (71%). Multivariate logistic regression revealed that the significant correlates of pilot fatality were aircraft fire [odds ratio (OR) 13.7, 95% confidence interval (CI) 6.9-27.2], off-airport location (OR 9.9, 95% CI 5.0-19.6), IMC (OR 9.1, 95% CI 4.3-19.6), nighttime (OR 2.2, 95% CI 1.3-3.7), and pilot age > or = 50 yr (OR 1.7, 95% CI 1.0-3.0). Pilot gender, flight experience, principal profession, and type of aircraft (airplane vs. helicopter) were not significantly associated with the likelihood of survival.

CONCLUSIONS

The most important correlates of pilot fatality are variables likely related to increased impact forces. Better occupant protection equipment, such as air bag and crashworthy fuel system, are needed for general aviation aircraft.

The epidemiology of ocular injury in a major US automobile corporation

PURPOSE

Although occupational eye injuries account for a large proportion of ocular injuries, few industry-specific data have been published. To address this problem, we examined the epidemiology of eye injuries in a large automobile corporation.

METHODS

The study population included all hourly-paid persons employed between July 1989 and June 1992 at 33 plants of the UAW-Chrysler Corporation. Incident ocular injury data were obtained from an active surveillance system. Year-end employee censuses were used to estimate the population at risk.

RESULTS

A total of 1983 work-related eye injuries occurred over the 3 year period, with an incidence rate of 14.9 per 1000 person-years. Workers aged 20-29 years had the highest incidence of eye injuries (28.2 per 1000 person-years). Men had a higher incidence of injury than women across all ages, with an age-adjusted incidence of 15.6 per 1000 person-years and age-adjusted relative risk of 1.5 (95% confidence interval: 1.4, 1.6). Superficial foreign bodies and corneal abrasions made up 86.7% of all injuries while open globe injury occurred in only 3 cases. Only 25% of workers had been using some form of eye protection at the time of injury. Almost one-third (32.3%) of ocular injuries resulted in the inability of workers to resume their normal duties for at least 1 day.

CONCLUSION

Workplace eye injuries in the automotive industry account for significant avoidable morbidity and lost productivity.

Structure-affinity profile of 8-hydroxycarbostyril-based agonists that dissociate slowly from the beta2-adrenoceptor

Several carbostyril-based beta-agonists have been shown to bind tightly to and slowly dissociate from the beta2-adrenoceptor (beta2AR). In the present study, the structural features of 8-hydroxy-5-[2-[(1-phenyl-2-methylprop-2-yl)amino]-1-hydroxyethyl] -carbostyril (11a) which contribute to its binding properties at the beta2AR were investigated using a series of synthesized analogs. The k(off), estimated by the rate of cAMP decline in DDT1 MF-2 (DDT) cells with a reduced receptor density, Ki and ligand-induced receptor reductions were determined. All of the derivatives stimulated cAMP accumulation in DDT cells in the sub to mid nanomolar range and elicited the same maximal stimulation as (-)isoproterenol. Derivatives of 11a with side chain N-substitutions comprising 2-methylbutyl, phenylethyl and isopropyl had higher k(off)-values and lower affinities as compared to 11a. Increasing the number of methylenes between the side chain tertiary alpha carbon and phenyl from 1 in 11a to 3 or reducing the number to 0 also resulted in derivatives with higher k(off)- and Ki-values. In addition, replacement of the 8-hydroxycarbostyril nucleus of 11a with catechol reduced the affinity of the compound for the beta2AR by 48-fold and increased its k(off). Only those derivatives with the lowest k(off)-values induced a decrease in the receptor density of DDT cell membranes following a preincubation and extensive washing. The data show that the 8-hydroxycarbostyril nucleus in conjunction with substitutions on the tertiary alpha carbon of the side chain and positioning of the phenyl group are important characteristics determining the high affinity and slow dissociation of 11a from the beta2AR.

Effects of high school driver education on motor vehicle crashes, violations, and licensure

OBJECTIVE

We sought evidence in the research literature to determine if (1) high school-aged persons who enroll in a driver education course have fewer motor vehicle-related crashes or violations, or are more likely to obtain a drivers license, than those who do not enroll in driver education courses, and (2) the availability of high school driver education courses is associated with lower community rates of motor vehicle crashes among young drivers.

METHODS

To be included, a study must: (1) assess the effects of driver education courses or legislation for high school-aged persons; (2) present non-self-reported data for at least one of the following outcome measures: driver licensure rates, motor vehicle-related violations, or crashes; (3) include some form of no intervention comparison group; (4) adequately control for potentially confounding variables; (5) randomly assign participants to control or treatment groups, if a controlled trial.

RESULTS

Nine studies met our inclusion criteria. Based on these studies, there is no convincing evidence that high school driver education reduces motor vehicle crash involvement rates for young drivers, either at the individual or community level. In fact, by providing an opportunity for early licensure, there is evidence that these courses are associated with higher crash involvement rates for young drivers.

CONCLUSIONS

Although few driver education curricula have been carefully evaluated, in the absence of evidence that driver education reduces crash involvement rates for young persons, schools and communities should consider other ways to reduce motor vehicle-related deaths in this population, such as graduated licensing.

N6-(5,6-epoxynorbornyl)adenosine analogs as A1 adenosine agonists

A range of related adenosines and 5'-N-ethylcarboxamidoadenosines bearing oxygenated substituents in the N6 position have been synthesised and evaluated as A1-adenosine receptor ligands. Compound 9 emerged with potent affinity (EC50 = 1.1 nM).