Sun Exposure Prevention Practices Within U.S. Naval Aviation.

INTRODUCTION: Occupational exposure to ultraviolet radiation is a critical concern for those serving in the U.S. Military. Work and mission requirements predispose members to significant sun exposure, while sun-protective behavior often comes second to mission accomplishment. Prior research implicated institutional practices and constraints as preventing the routine use of sun protection modalities, but no large-scale studies have assessed service members' perceptions regarding sun protection modalities available to them in their work environment or their daily sun protection practices. METHODS: The study employed a cross-sectional survey distributed to active duty (AD) U.S. Navy service members assigned to 1 of 19 aircraft squadrons based in Southern California and deployed on missions across the Pacific theater of operations. The intent was to evaluate rates of sunburn, sun-protective practices, and perceptions regarding sun exposure and prevention practices in their workplace. The study and survey tool received approval from the Naval Medical Center San Diego Institutional Review Board. Statistical analysis of survey answers was performed to assess for trends in response rates overall and response rates within sociodemographic groups. Pearson's chi-squared tests were utilized to assess for significance where appropriate. P-values <.05 were used to determine statistically significant trends in response rates. RESULTS: One thousand surveys were distributed, of which 896 surveys were completed. The response rate was 89.6%. Eight hundred and eighty-eight surveys were included in the analysis. The surveyed population was consistent with the demographics of the U.S. Navy as a whole. 55.1% of survey respondents reported sunburn within the past year, higher than the rate reported in a previously surveyed civilian population. Reports of sunburn within the past year were not significantly different in regard to gender (P = .88), age (P = .53), and years of AD (P = .48). Increasing rank did show a significant correlation with reports of sunburn (P = .0) (Table S1). 62.2% of those surveyed reported frequent/routine use of some form of sun protection. This was lower than the rate reported in a previously surveyed civilian population. A large majority of service members surveyed (75.9%) reported using sunscreen with a sun protection factor >15.29.1% of survey respondents reported working in direct sunlight always/almost always. This was lower than the rates reported in a previously surveyed U.S. Air Force population of aviation maintainers. Low rates of respondents reported frequent reminders to use sun protection (18.9%), and fewer reported the routine or frequent use of sunscreen while at work (12.3%). A higher percentage reported regular use of sunscreen during outdoor leisure activities (36.5%), suggesting a barrier to use in the workplace. CONCLUSIONS: U.S. Military personnel report higher rates of sunburn and lower rates of routine use of sun protection practices compared to a previously surveyed civilian population. The overall rates of sun protection use while in the work setting are low both overall and compared to reports of routine use during outdoor leisure activities. Reported rates of reminders to use sunscreen are low, suggesting that increased education regarding the risk of excessive sun exposure and tools for effective sun protection are still needed.

Triage and Treatment of Mass Casualty Decompression Sickness After Depressurization at 6400 m.

BACKGROUND: Decompression sickness is a condition that results from an abrupt change from a higher to a lower pressure. It is described most commonly in divers; however, it can occur in aviation incidents, which this case report will discuss.CASE REPORT: Following an acute cabin depressurization incident, 36 patients presented to a small outpatient clinic with multiple symptoms, including fatigue, headache, nausea, vomiting, and dizziness. These patients were evaluated, triaged, and some were able to be successfully treated with supplemental oxygen in clinic. Eight of the patients had symptoms that were either persistent or concerning enough that they were referred to the dive medical clinic, where the dive medical team diagnosed six of the patients with Type II decompression sickness and referred them for hyperbaric oxygen chamber therapy. All patients who received hyperbaric therapy experienced at least some relief of symptoms, with most reporting some residual fatigue after the therapy.DISCUSSION: This case provided both lessons in triage and management of multiple patients in a small outpatient clinic, as well as the challenges in making the diagnosis of decompression sickness.Mancini S, Crotty AM, Cook J. Triage and treatment of mass casualty decompression sickness after depressurization at 6400 m. Aerosp Med Hum Perform. 2018; 89(12):1085-1088.

Passivating ligand and solvent contributions to the electronic properties of semiconductor nanocrystals.

We examine in detail the impact of passivating ligands (i.e., amines, phosphines, phosphine oxides and pyridines) on the electronic and optical spectra of Cd(33)Se(33) quantum dots (QDs) using density functional theory (DFT) and time-dependent DFT (TDDFT) quantum-chemical methodologies. Most ligand orbitals are found deep inside in the valence and conduction bands of the QD, with pyridine being an exception by introducing new states close to the conduction band edge. Importantly, all ligands contribute states which are highly delocalized over both the QD surface and ligands, forming hybridized orbitals rather than ligand-localized trap states. In contrast, the states close to the band gap are delocalized over the QD atoms only and define the lower energy absorption spectra. The random detachment of one of ligands from the QD surface results in the appearance of a highly localized unoccupied state inside the energy gap of the QD. Such changes in the electronic structure are correlated with the respective QD-ligand binding energy and steric ligand-ligand interactions. Polar solvent significantly reduces both effects leading to delocalization and stabilization of the surface states. Thus, trap and surface states are substantially eliminated by the solvent. Polar solvent also blue-shifts (e.g., 0.3-0.4 eV in acetonitrile) the calculated absorption spectra. This shift increases with an increase of the dielectric constant of the solvent. We also found that the approximate single-particle Kohn-Sham (KS) approach is adequate for calculating the absorption spectra of the ligated QDs. Besides a systematic blue-shift, the KS spectra are in very good agreement with their respective counterparts calculated with the more accurate TDDFT method.