Mouse pulmonary response to dust from sawing Corian®, a solid-surface composite material.

Corian®, a solid-surface composite (SSC), is composed of alumina trihydrate and acrylic polymer. The aim of the present study was to examine the pulmonary toxicity attributed to exposure to SSC sawing dust. Male mice were exposed to either phosphate buffer saline (PBS, control), 62.5, 125, 250, 500, or 1000 µg of SSC dust, or 1000 µg silica (positive control) via oropharyngeal aspiration. Body weights were measured for the duration of the study. Bronchoalveolar lavage fluid (BALF) and tissues were collected for analysis at 1 and 14 days post-exposure. Enhanced-darkfield and histopathologic analysis was performed to assess particle distribution and inflammatory responses. BALF cells and inflammatory cytokines were measured. The geometric mean diameter of SSC sawing dust following suspension in PBS was 1.25 µm. BALF analysis indicated that lactate dehydrogenase (LDH) activity, inflammatory cells, and pro-inflammatory cytokines were significantly elevated in the 500 and 1000 µg SSC exposure groups at days 1 and 14, suggesting that exposure to these concentrations of SSC induced inflammatory responses, in some cases to a greater degree than the silica positive control. Histopathology indicated the presence of acute alveolitis at all doses at day 1, which was largely resolved by day 14. Alveolar particle deposition and granulomatous mass formation were observed in all exposure groups at day 14. The SSC particles were poorly cleared, with 81% remaining at the end of the observation period. These findings demonstrate that SSC sawing dust exposure induces pulmonary inflammation and damage that warrants further investigation. Abbreviations: ANOVA: Analysis of Variance; ATH: Alumina Trihydrate; BALF: Bronchoalveolar Lavage Fluid; Dpg: Geometric Mean Diameter; FE-SEM: Field Emission Scanning Electron Microscopy; IACUC: Institutional Animal Care and Use Committee; IFN-γ: Interferon Gamma; IL-1 Β: Interleukin-1 Beta; IL-10: Interleukin-10; IL-12: Interleukin-12; IL-2: Interleukin-2; IL-4: Interleukin-4; IL-5: Interleukin-5; IL-6: Interleukin-6; KC/GRO: Neutrophil-Activating Protein 3; MMAD: Mass Median Aerodynamic Diameter; PBS: Phosphate-Buffered Saline; PEL: Permissible Exposure Limit; PM: Polymorphonuclear Leukocytes; PNOR: Particles Not Otherwise Regulated; SEM/EDX: Scanning Electron Microscope/Energy-Dispersive X-Ray; SSA: Specific Surface Area; SSC: Solid Surface Composite; TNFα: Tumor Necrosis Factor-Alpha; VOC: Volatile Organic Compounds; σg: Geometric Standard Deviation.

Influence of Work Characteristics on the Association Between Police Stress and Sleep Quality.

BACKGROUND: Police officers' stress perception, frequency of stressful events (stressors), and police work characteristics may contribute to poor sleep quality through different mechanisms. METHODS: We investigated associations of stress severity (measured by stress rating score) and frequency of stressors with sleep quality and examined the influence of police work characteristics including workload, police rank, prior military experience, and shift work on the associations. Participants were 356 police officers (256 men and 100 women) enrolled in the Buffalo Cardio-Metabolic Occupational Police Stress Study from 2004 to 2009. A mean stress rating score and mean frequency of stressors occurring in the past month were computed for each participant from the Spielberger Police Stress Survey data. Sleep quality was assessed using the global score derived from the Pittsburgh Sleep Quality Index survey. Linear associations of the stress rating score and frequency of stressors with sleep quality (Pittsburgh Sleep Quality Index global score) were tested. Age, sex, race/ethnicity, and smoking status were selected as potential confounders. RESULTS: The stress rating score was positively and independently associated with poor sleep quality (ß = 0.17, p = 0.002). Only workload significantly modified this association (ß = 0.23, p = 0.001 for high workload group; p-interaction = 0.109). The frequency of stressors was positively and independently associated with poor sleep quality (ß = 0.13, p = 0.025). Only police rank significantly modified the association (ß = 0.007, p = 0.004 for detectives/other executives; p-interaction = 0.076). CONCLUSION: Both police officers' perception of stress severity and the frequency of stressors are associated with poor sleep quality. Stress coping or sleep promotion regimens may be more beneficial among police officers reporting high workloads.

Can Blood Flow be Used to Monitor Changes in Peripheral Vascular Function That Occur in Response to Segmental Vibration Exposure?

OBJECTIVES: Laser Doppler blood flow measurements have been used for diagnosis or detection of peripheral vascular dysfunction. This study used a rat tail model of vibration-induced vascular injury to determine how laser Doppler measurements were affected by acute and repeated exposures to vibration, and to identify changes in the Doppler signal that were associated with the exposure. METHODS: Blood flow was measured immediately after a single exposure to vibration, or before vibration exposure on days 1, 5, 10, 15, and 20 of a 20 days exposure. RESULTS: After a single exposure to vibration, average tail blood flow was reduced. With 20 days of exposure, there was a reduction in the amplitude of the arterial pulse on days 10 to 20 in vibrated rats and days 15 to 20 in control rats. CONCLUSIONS: More detailed statistical analyses of laser Doppler data may be needed to identify early changes in peripheral circulation after exposure to vibration.

Stressful life events and posttraumatic growth among police officers: A cross-sectional study.

Police officers often continue to face numerous threats and stressors in the aftermath of a disaster. To date, posttraumatic growth (PTG) has been studied primarily in the context of significant trauma; thus, it is not known whether stressful life events are associated with PTG. This study investigated the development of PTG among 113 police officers working in the New Orleans area following Hurricane Katrina. Hierarchical regression was used to evaluate if gratitude, social support, and satisfaction with life moderated the relationship between stressful life events (as measured by the total life stress score) and PTG, after adjustment for age, sex, race, level of involvement in Hurricane Katrina, and alcohol intake. Results indicate that stressful life events are independently associated with PTG. Gratitude, satisfaction with life, and social support were seen to moderate this relationship; as stressful life events increased so too did PTG-particularly among officers with higher levels of gratitude (B = 0.002, p ≤ .05), satisfaction with life (B = 0.002, p ≤ .05), and social support (B = 0.001, p ≤ .05). These findings suggest that promoting satisfaction with life, interpersonal support, and gratitude may be beneficial to those who are regularly at risk of trauma exposure.

Association of peritraumatic dissociation with symptoms of depression and posttraumatic stress disorder.

AIM: In this study, we evaluated whether peritraumatic dissociation (PD) was associated with symptoms of depression and posttraumatic stress disorder (PTSD), and whether this association was modified by trauma prior to police work. METHOD: Symptoms of depression, PTSD, peritraumatic dissociative experience (PDE), and trauma prior to police work were measured using the Center for Epidemiologic Studies Depression scale, PTSD Checklist-Civilian, PDE questionnaire, and the Brief Trauma questionnaire, respectively, in 328 police officers. Separate regression models were used to assess if either symptoms of depression or PTSD were associated with PD stratified by prior trauma. Means were adjusted for race, number of drinks per week, and smoking. RESULTS: PD was associated with symptoms of PTSD and depression (ß = 0.65, p < .001 and ß = 0.27, p < .001, respectively). PD was positively associated with symptoms of PTSD regardless of prior trauma (ß = 0.61, p < .001(without prior trauma), 0.75, p < .001 (with prior trauma). In contrast to PTSD, depression symptoms were significantly associated with PD scores in individuals with prior trauma (ß = 0.47, p < .001), but not in individuals without prior trauma (ß = 0.13, p = .165). LIMITATIONS: This is a cross-sectional study. Outcomes were obtained via self-report and were not clinically diagnosed. Aspects of both the trauma event as well as the symptoms and severity of PD may have introduced recall bias. CONCLUSION: These results add to the literature indicating that PD plays a role in symptoms of PTSD and depression and how prior trauma may modify this relationship. (PsycINFO Database Record

Effects of Ultraviolet Germicidal Irradiation (UVGI) on N95 Respirator Filtration Performance and Structural Integrity.

The ability to disinfect and reuse disposable N95 filtering facepiece respirators (FFRs) may be needed during a pandemic of an infectious respiratory disease such as influenza. Ultraviolet germicidal irradiation (UVGI) is one possible method for respirator disinfection. However, UV radiation degrades polymers, which presents the possibility that UVGI exposure could degrade the ability of a disposable respirator to protect the worker. To study this, we exposed both sides of material coupons and respirator straps from four models of N95 FFRs to UVGI doses from 120-950 J/cm(2). We then tested the particle penetration, flow resistance, and bursting strengths of the individual respirator coupon layers, and the breaking strength of the respirator straps. We found that UVGI exposure led to a small increase in particle penetration (up to 1.25%) and had little effect on the flow resistance. UVGI exposure had a more pronounced effect on the strengths of the respirator materials. At the higher UVGI doses, the strength of the layers of respirator material was substantially reduced (in some cases, by >90%). The changes in the strengths of the respirator materials varied considerably among the different models of respirators. UVGI had less of an effect on the respirator straps; a dose of 2360 J/cm(2) reduced the breaking strength of the straps by 20-51%. Our results suggest that UVGI could be used to effectively disinfect disposable respirators for reuse, but the maximum number of disinfection cycles will be limited by the respirator model and the UVGI dose required to inactivate the pathogen.

A comparison of two laboratories for the measurement of wood dust using button sampler and diffuse reflection infrared Fourier-transform spectroscopy (DRIFTS).

The current measurement method for occupational exposure to wood dust is by gravimetric analysis and is thus non-specific. In this work, diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) for the analysis of only the wood component of dust was further evaluated by analysis of the same samples between two laboratories. Field samples were collected from six wood product factories using 25-mm glass fiber filters with the Button aerosol sampler. Gravimetric mass was determined in one laboratory by weighing the filters before and after aerosol collection. Diffuse reflection mid-infrared spectra were obtained from the wood dust on the filter which is placed on a motorized stage inside the spectrometer. The metric used for the DRIFTS analysis was the intensity of the carbonyl band in cellulose and hemicellulose at ~1735 cm(-1). Calibration curves were constructed separately in both laboratories using the same sets of prepared filters from the inhalable sampling fraction of red oak, southern yellow pine, and western red cedar in the range of 0.125-4 mg of wood dust. Using the same procedure in both laboratories to build the calibration curve and analyze the field samples, 62.3% of the samples measured within 25% of the average result with a mean difference between the laboratories of 18.5%. Some observations are included as to how the calibration and analysis can be improved. In particular, determining the wood type on each sample to allow matching to the most appropriate calibration increases the apparent proportion of wood dust in the sample and this likely provides more realistic DRIFTS results.

Leptin, adiponectin, and heart rate variability among police officers.

OBJECTIVES: Police officers have a high prevalence of cardiovascular disease (CVD). Reduced heart rate variability (HRV) is known to increase CVD risk. Leptin and adiponectin may be related to CVD health. Therefore, our objective was to investigate the relationship between these variables and HRV. METHODS: Leptin and adiponectin levels were measured in 388 officers from the Buffalo Cardio-Metabolic Occupational Police Stress study. HRV was assessed according to methods published by the Task Force of the European Society of Cardiology and the North American Society of Pacing Electrophysiology for measurement and analysis of HRV. Mean values of high-frequency (HF) and low-frequency (LF) HRV were compared across tertiles of leptin and adiponectin using analysis of variance and analysis of covariance; trends were assessed using linear regression models. RESULTS: Leptin, but not adiponectin, was significantly and inversely associated with HRV. Body mass index (BMI) and percent body fat significantly modified the association between leptin and LF (but not HF) HRV. Among officers with BMI < 25 kg/m(2) , leptin was not significantly associated with HRV. However, among officers with BMI ≥ 25 kg/m(2) , leptin was inversely associated with HRV, after adjustment for age, gender, and race/ethnicity; HF HRV, P = 0.019 and LF HRV, P < 0.0001. Similarly, among officers with percent body fat ≥ 25.5%, leptin and LF HRV showed significant, inverse associations (adjusted P = 0.001). CONCLUSIONS: Leptin levels were inversely associated with LF HRV, especially among officers with increased adiposity. Increased leptin levels may be associated with CVD-related health problems.

Approximation of the ruin probability using the scaled Laplace transform inversion.

The problem of recovering the ruin probability in the classical risk model based on the scaled Laplace transform inversion is studied. It is shown how to overcome the problem of evaluating the ruin probability at large values of an initial surplus process. Comparisons of proposed approximations with the ones based on the Laplace transform inversions using a fixed Talbot algorithm as well as on the ones using the Trefethen-Weideman-Schmelzer and maximum entropy methods are presented via a simulation study.

Associations between insulin and heart rate variability in police officers.

OBJECTIVE: Low heart rate variability (HRV) has been linked to cardiovascular disease. Our objective was to examine the cross-sectional association between insulin and HRV. METHODS: Insulin levels were measured in 355 nondiabetic officers from the BCOPS study, following a 12 h fast. HRV was performed according to methods published by the task force of the European Society of Cardiology and the North American Society of Pacing Electrophysiology for measurement and analysis of HRV. Mean values of high (HF) and low frequency (LF) HRV were compared across tertiles of insulin using ANOVA and ANCOVA; p-values were obtained from linear regression models. RESULTS: Higher mean levels of insulin were significantly associated with lower (i.e., worse) mean levels of HRV before and after risk-factor adjustment. The results for HF HRV (ms(2)) were as follows: 1st insulin (µU/ml) tertile (156.3; 95% confidence interval (CI) = 128.6-189.9); 2nd tertile (154.3; 95% CI = 124.3-191.5); 3rd tertile (127.9; 95% CI = 105.0-155.8), p for trend = 0.017. Results with LF HRV were similar to HF HRV. Insulin was also inversely and significantly associated with HRV among officers with BMI ≥ 25 kg/m(2), with ≥ 25.5% body fat, and among those who reported low (

Association Between Police-Specific Stressors and Sleep Quality: Influence of Coping and Depressive Symptoms.

Police officers work in an environment of chronic psychological stress which may be associated with sleep quality. Variation in sleep quality may be a result of how well officers cope with stress. The purpose of this study was to examine associations between police-specific stresses and sleep quality, and factors which may modify these associations. Participants were 356 police officers (256 men, 100 women) from the Buffalo Cardio-metabolic Occupational Police Stress (BCOPS) Study examined between 2004 and 2009. Stress in the past year, including organizational, physical and psychological danger and lack of support, was measured using the Spielberger Police Stress Survey. Sleep quality was measured using the Pittsburgh Sleep Quality Index. Analysis of covariance was used to examine multivariable-adjusted sleep quality across police stress tertiles; p-values were obtained from linear regression. Adjustments were made for age, gender, race, education, marital and smoking status. Analyses were stratified by coping and depressive symptoms, potential moderators of the association of interest. Multivariable-adjusted global sleep and sleep disturbance scores increased significantly with increasing tertiles of police stress scores for the total and subscale scores (p<0.005). The association with global sleep was significant for those who used more passive coping strategies (p<0.007). The association with sleep disturbances was significant for those with higher levels of depressive symptoms (p<0.003) and passive coping (p<0.001). These findings demonstrate that different types of police stress may adversely affect sleep quality, and those who use passive coping strategies, such as self-blame or denial, and those with higher depressive symptoms may be more adversely affected by police stress.

A note on recovering the distributions from exponential moments.

The problem of recovering a cumulative distribution function of a positive random variable via the scaled Laplace transform inversion is studied. The uniform upper bound of proposed approximation is derived. The approximation of a compound Poisson distribution as well as the estimation of a distribution function of the summands given the sample from a compound Poisson distribution are investigated. Applying the simulation study, the question of selecting the optimal scaling parameter of the proposed Laplace transform inversion is considered. The behavior of the approximants are demonstrated via plots and table.

Association of traumatic police event exposure with sleep quality and quantity in the BCOPS Study cohort.

Police officers are exposed to traumatic and life-threatening events, which may lead to sleep problems. Prior studies of police officers have found them to have poor sleep quality and reduced sleep time. This study examined associations between traumatic events and sleep quality. Participants were 372 police officers from the Buffalo Cardio-metabolic Occupational Police Stress (BCOPS) Study. Police incidents were measured by the Police Incident Survey; sleep quality and quantity were derived from the Pittsburgh Sleep Quality Index (PSQI). Analysis of covariance (ANCOVA) was used to examine mean PSQI scores across categories of traumatic event frequency. Models were adjusted for age, education and ethnicity and stratified by sex and workload. In men, significant associations were found for the 'shooting of another officer' and sleep quality (p-value = 0.024) and sleep disturbances (p-value = 0.022). In women, seeing more 'abused children' was associated with poorer sleep quality (p-value = 0.050); increasing frequency of 'seeing victims of a serious traffic accident' was associated with shorter sleep duration (p-value = 0.032). Increased frequency of 'seeing dead bodies' was associated with poorer sleep quality (p-value = 0.040) and shorter sleep duration (p-value = 0.048). Among women with a high workload, a significant inverse association was found between 'seeing serious traffic accident victims' and global sleep quality (p-value = 0.031). In conclusion, a significant inverse association between frequency of select traumatic events and sleep quality was found in male and female police officers. The significant events differed by sex. Future research could examine longitudinal associations between career-long traumatic event exposures and sleep quality and how these associations differ by sex.

PTSD symptoms among police officers: associations with frequency, recency, and types of traumatic events.

Policing necessitates exposure to traumatic, violent and horrific events, which can lead to an increased risk for developing post-traumatic stress disorder (PTSD). The purpose of this study was to determine whether the frequency, recency, and type of police-specific traumatic events were associated with PTSD symptoms. Participants were 359 police officers from the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) Study (2004-2009). Traumatic police events were measured using the Police Incident Survey (PIS); PTSD was measured using the PTSD Checklist-Civilian Version (PCL-C). Associations between PIS and PTSD symptoms were evaluated using ANCOVA. Contrast statements were used to test for linear trends. Increased frequency of specific types of events were associated with an increase in the PCL-C score in women, particularly women with no history of prior trauma and those who reported having a high workload (p < 0.05). More recent exposure to seeing severely assaulted victims was associated with higher PCL-C scores in men (p < 0.02). In summary, the frequency of several traumatic events was associated with higher PTSD scores in women, while the recency of seeing victims of assault was associated with higher PTSD scores in men. These results may be helpful in developing intervention strategies to reduce the psychological effects following exposure and these strategies may be different for men and women.

Long work hours and adiposity among police officers in a US northeast city.

OBJECTIVE: To investigate the associations between long work hours and adiposity measures in police officers. METHODS: Participants included 408 officers from the Buffalo Cardio-Metabolic Occupational Police Stress study who were examined between 2004 and 2009. Total work hours were abstracted from payroll records and questionnaires. Analysis of variance and covariance models were used. RESULTS: Among male officers who worked the midnight shift, mean values of waist circumference and body mass index increased with longer work hours after adjustment for age, physical activity, energy intake, sleep duration, smoking status, police rank, activities after work (eg, child/family care, sports), and household income. Adiposity measures were not associated with work hours among women on any shift. CONCLUSION: Working longer hours was significantly associated with larger waist circumferences and higher body mass index among male police officers working the midnight shift.

Varying kernel density estimation on ℝ.

In this article a new nonparametric density estimator based on the sequence of asymmetric kernels is proposed. This method is natural when estimating an unknown density function of a positive random variable. The rates of Mean Squared Error, Mean Integrated Squared Error, and the L1-consistency are investigated. Simulation studies are conducted to compare a new estimator and its modified version with traditional kernel density construction.