Law enforcement is a popular occupation for scrutiny both in the general population and psychology. Two particular topics in the psychological study of police officers are cynicism and stress. The ...study of police cynicism reached its zenith in the 1980s, but it has slowed in the present day. Many questions remain unresolved, such as the potential antecedents of cynicism like rank, age length of service, education, negative affectivity, supportive leadership behaviors, and perceived community attitudes towards the police. Job satisfaction is proposed as a potential consequence of cynicism. Regarding police stress, the existing literature documented the activities that police officers used to relieve stress. However, the current study moved beyond documentation and provides evidence for the effectiveness of several potential buffers of the stressor-strain relationship, including exercise, alcohol consumption, caffeine consumption, sense of humor, and cynicism. Two hundred five officers representing 16 departments of a Midwestern state completed an anonymous survey and mailed it back to the researcher. Data were analyzed with correlations and multiple regressions. Age, rank, supportive leadership behaviors, community attitudes, and job satisfaction were negatively related to cynicism. In addition, negative affectivity was positively related to cynicism. Caffeine consumption was a reverse buffer of the relationship between stressors and strains, indicating that increased caffeine consumption strengthened the relationship between stressors and strains. The results have important implications for the causes of cynicism and effective ways of reducing stress in police officers.
A 23-year-old woman with known nasal polyps and a recent seizure presented with diplopia, proptosis, extraocular motility deficits, and stigmata of Cushing syndrome. Computed tomography showed a left ...sinonasal mass extending into the left orbit. Laboratory evaluation revealed refractory hypokalemia and significantly elevated adrenocorticotropic hormone. Histopathologic exam confirmed the diagnosis of esthesioneuroblastoma.
Background: Dialyzers reprocessed with chlorine-based solutions have been associated with increases in ultrafiltration coefficient and middle-molecule removal. Increased pore size has been ...hypothesized as the mechanism for the latter phenomenon. Dialyzers exposed to Amukin-D (Amuchina Int Inc, Gaithersburg, MD), a chlorine-based reprocessing agent, were evaluated for changes in molecular weight (MW) cutoff and ultrafiltration properties. Methods: In vitro MW cutoff studies were performed on Fresenius F-80A (Fresenius, Lexington, MA) and Gambro Polyflux 17 (Gambro, Lakewood, CO) hemodialyzers that were reprocessed 20 times using Amukin-D. Permeability (Uf-A), defined as the area from the ultrafiltered compartment (Uf) compared with the area from the equivalent arterial compartment (A), for dextran across the hemodialyzer membrane was determined after the initial use and after reuses 1, 5, 10, 15, and 20 by using size-exclusion chromatography. Results: Uf-A for dextran increased approximately 10-fold between hemodialyzer reuses 1 and 5. Thereafter, additional reprocessing did not increase the Uf-A ratio further. MW cutoff increased during these 5 washes and did not change thereafter. Conclusion: Reprocessing with Amukin-D increased the MW cutoff and permeability of both hemodialyzers between reuses 1 and 5, resulting in a greater ultrafiltration rate and greater middle-molecule removal. After reuse 5, there were no further increases in MW cutoff with additional reprocessing in either hemodialyzer. This suggests that reprocessing and storage of each hemodialyzer with Amukin-D affects the permeability of dextran in a nonlinear fashion and to a finite level, such that subsequent reprocessing has no further effect on the MW cutoff of the membrane.
Planetary sample sealing for caching Backes, P.; Onstott, T.; Bar-Cohen, Y. ...
2009 IEEE Aerospace conference,
2009-March
Conference Proceeding
A sample sealing technique was developed and tested for a possible Mars Sample Return mission application. The effect on the scientific viability of biological samples from storage of samples in a ...sample container for a long period of time on the Martian surface was also investigated. Sealing techniques were investigated and a soldering concept was developed and tested to provide a hermetic seal between a sample tube and cap. A sample caching subsystem design concept was updated to allow for sealing of sample tubes. A gas-tight vessel was constructed that could be used to simulate environmental conditions that would be experienced by a sample of regolith on Mars and to test the affects of thermal cycling of the vessel on psychrophilic microorganisms embedded in a regolith simulant to assess the degree of deterioration of the microorganisms.
Escherichia colil-threonine dehydrogenase is a member of the Zn2+-containing alcohol/polyol dehydrogenase family. Methylation of His-90 ofl-threonine dehydrogenase was recently found to cause total ...inactivation (J. P. Marcus and E. E. Dekker, 1995Arch. Biochem. Biophys.316, 413–420). Since His-90 is not conserved among the related dehydrogenases, this residue was changed to arginine, asparagine, and alanine by site-directed mutagenesis in order to probe its role. All three purified, homogeneous mutants, like wild-type enzyme, contained one Zn2+atom/subunit and exhibited a sequential catalytic mechanism; thekcatvalue for each, however, was reduced ∼10-fold. TheKmvalue for threonine was elevated from 3 mM for wild-type enzyme to 31, 328, and 417 mM, respectively, for mutants H90R, H90N, and H90A. The activation energy of catalysis for mutant H90A was increased by 6.6 kcal/mol, suggesting that in the wild-type enzyme His-90 forms at least one crucial hydrogen bond in the transition state. Whereas wild-type enzyme catalyzed the oxidation of threonine amide (0.75 M) about twice as fast as this same concentration of threonine or 0.375 Ml-2-amino-3-hydroxypentanoate, the reaction rate of mutant H90A with 0.75 M threonine amide or threonine methyl ester was 33- to 35-fold higher than with this level of threonine. Similarly, mutant H90N used 0.75 M threonine methyl ester or threonine amide as substrate 9- to 13-fold better than it used this concentration of threonine. Mutants H90A and H90N were more reactive with 0.225 Ml-threonine hydroxamate than with 0.75 M threonine, but mutant H90A did not oxidizel-2-amino-3-hydroxypentanoate (0.375 M) and mutant H90N used this substrate poorly. The best substrates for mutant H90R were threonine methyl ester, threonine, and threonine amide (all tested at 0.75 M); 0.375 Ml-2-amino-3-hydroxypentanoate was a poor substrate. The isolation and characterization of these first His-90 mutants ofE. colil-threonine dehydrogenase confirm the importance of this residue in catalysis and suggest that His-90 is an active-site residue which modulates the substrate specificity ofl-threonine dehydrogenase.
Three-coordinate Ti(NRAr)3 R = C(CD3)2(CH3), Ar = C6H3Me2 was prepared in 73% yield by sodium amalgam reduction of ClTi(NRAr)3 and in 83% yield upon treatment of TiCl3(THF)3 with 3 equiv of ...Li(NRAr)(OEt2) in the presence of TMEDA. Ti(tBuNPh)3 was prepared similarly in 75% yield by treatment of TiCl3(THF)3 with 3 equiv of Li(tBuNPh)(OEt2) in the presence of TMEDA. Reaction of Ti(NRAr)3 with NMo(OtBu)3 in hydrocarbon solvents at −35 °C generates a thermally unstable intermediate formulated as (tBuO)3Moμ-NTi(NRAr)3, which readily loses a tert-butyl radical and isomerizes at 25 °C. Kinetics of the latter process were obtained over the temperature range 20−60 °C; the process exhibits clean first-order behavior. The following activation parameters were obtained: ΔH ⧧ = 21.4 ± 0.2 kcal mol-1 and ΔS ⧧ = −3.7 ± 0.6 cal mol-1 K-1. The oxo-bridged product (tBuO)2(N)Moμ-OTi(NRAr)3 was isolated in 83% yield from this reaction. Full characterization of the latter diamagnetic complex included an X-ray crystal structure and an 15N NMR study. Ti(NRAr)3 (1 equiv) reacts further with (tBuO)2(N)Moμ-OTi(NRAr)3 to generate a species formulated as a second paramagnetic nitrido-bridged intermediate, (tBuO)2Mo{μ-OTi(NRAr)3}{μ-NTi(NRAr)3}, which at 25 °C loses a tert-butyl radical and isomerizes to give the final product, (tBuO)(N)Mo{μ-OTi(NRAr)3}2, isolated as an orange powder in 91% yield. Characterization of the latter diamagnetic complex included an 15N NMR study. Attempts to displace a third tert-butyl radical by treatment of (tBuO)(N)Mo{μ-OTi(NRAr)3}2 with Ti(NRAr)3 led to no reaction. Treatment of (tBuO)(N)Mo{μ-OTi(NRAr)3}2 with neat methyl iodide led to the isolation of (MeO)(N)Mo{μ-OTi(NRAr)3}2 in 51% yield; 13C and nitrido-15N derivatives of this species were prepared for spectroscopic characterization. O2Mo{μ-OTi(tBuNPh)3}2 was prepared in 59% yield upon treatment of MoO2(OtBu)2 with 2 equiv of Ti(tBuNPh)3 in benzene at 65 °C. Full characterization of O2Mo{μ-OTi(tBuNPh)3}2 included a single-crystal X-ray diffraction study. Previously reported (iPrO)3Vμ-OTi(NRAr)3 was oxidized with ferrocenium triflate to give TfOTi(NRAr)3 and OV(OiPr)3. TfOTi(NRAr)3 was prepared independently in 80% yield by treatment of Ti(NRAr)3 with ferrocenium triflate. (iPrO)3Vμ-OTi(NRAr)3 is stable in the presence of methyl iodide. ITi(NRAr)3 was prepared independently by treatment of Ti(NRAr)3 with the stoichiometric amount of iodine. Paramagnetic (tBuO)3Vμ-OTi(NRAr)3 was prepared as orange-brown needles in 94% yield and was found to be thermally stable. The relatively robust μ-nitrido compound (Me2N)3Moμ-NTi(tBuNPh)3, which was prepared in 77% isolated yield, showed no decomposition when heated in benzene at 70 °C for 13 h.
The incidence of fatal closed head injury (CHI) and nonfatal CHI causing an altered level of consciousness in avalanche victims is unknown. The purpose of this study was to assess the incidence and ...potential significance of CHI in avalanche-related deaths.
The records of the state medical examiner and hospital records of all victims killed in avalanches in the state of Utah from October 1, 1992 through April 30, 1999 were reviewed for a cause of death and for the presence of CHI. Closed head injury was described as “present” or “severe,” depending on whether the degree of CHI was sufficient to have caused or directly contributed to death, as determined by the medical examiner.
In this review, 28 avalanche-related deaths were identified, of which 22 (79%) were due to asphyxia. Seventeen victims (61%) had evidence of some degree of CHI. Six victims (21%) had evidence of severe CHI. One of 7 snowmobile riders sustained a severe CHI, whereas 4 of 16 skiers or snowboarders sustained a severe CHI (
P
=
not significant).
Although asphyxiation was the cause of death in most avalanche victims, evidence of CHI was present in 61% of the cases studied. While avalanche-associated CHI may not be sufficient to cause death in many cases, a depressed level of consciousness might render a victim incapable of self-rescue and predispose to asphyxia. Helmet use may help prevent avalanche-associated CHI and thus be a useful safety adjunct.
