Geometric effects on stress wave propagation

The present study, through finite element simulations, shows the geometric effects of a bioinspired solid on pressure and impulse mitigation for an elastic, plastic, and viscoelastic material. Because of the bioinspired geometries, stress wave mitigation became apparent in a nonintuitive manner such that potential real-world applications in human protective gear designs are realizable. In nature, there are several toroidal designs that are employed for mitigating stress waves; examples include the hyoid bone on the back of a woodpecker's jaw that extends around the skull to its nose and a ram's horn. This study evaluates four different geometries with the same length and same initial cross-sectional diameter at the impact location in three-dimensional finite element analyses. The geometries in increasing complexity were the following: (1) a round cylinder, (2) a round cylinder that was tapered to a point, (3) a round cylinder that was spiraled in a two dimensional plane, and (4) a round cylinder that was tapered and spiraled in a two-dimensional plane. The results show that the tapered spiral geometry mitigated the greatest amount of pressure and impulse (approximately 98% mitigation) when compared to the cylinder regardless of material type (elastic, plastic, and viscoelastic) and regardless of input pressure signature. The specimen taper effectively mitigated the stress wave as a result of uniaxial deformational processes and an induced shear that arose from its geometry. Due to the decreasing cross-sectional area arising from the taper, the local uniaxial and shear stresses increased along the specimen length. The spiral induced even greater shear stresses that help mitigate the stress wave and also induced transverse displacements at the tip such that minimal wave reflections occurred. This phenomenon arose although only longitudinal waves were introduced as the initial boundary condition (BC). In nature, when shearing occurs within or between materials (friction), dissipation usually results helping the mitigation of the stress wave and is illustrated in this study with the taper and spiral geometries. The combined taper and spiral optimized stress wave mitigation in terms of the pressure and impulse; thus providing insight into the ram's horn design and woodpecker hyoid designs found in nature.

Is it time for a tobacco-free military?

Achieving a tobacco-free military requires rethinking current perceptions of service members' tobacco use and unmasking the forces perpetuating those perceptions. Prohibiting tobacco use would be entirely consistent with other military requirements regarding health.

A longitudinal analysis of cigarette prices in military retail outlets

OBJECTIVES

We conducted a longitudinal assessment of tobacco pricing in military retail outlets, including trends within each service branch.

METHODS

We determined the price of a single pack of Marlboro Red cigarettes at military retail stores located in the continental United States, Alaska, and Hawaii and at their nearest Walmarts in spring 2011 and 2013 (n = 128 for pairs available at both assessments).

RESULTS

The average difference between cigarettes sold in military retail outlets and Walmarts decreased from 24.5% in 2011 to 12.5% in 2013. The decrease was partially attributable to significant price decreases at Walmarts. The largest increases in cigarette prices occurred on naval installations. Potential savings at stores on several installations remained substantial in 2013; the largest approached $6 per pack. Stores on 17 military installations decreased cigarette prices during the study period.

CONCLUSIONS

Tobacco can be purchased in military retail stores at substantial savings over civilian stores. If tobacco pricing is to cease to be an incentive for use among personnel, a revised military tobacco pricing policy is needed.

Cigarette prices in military retail: a review and proposal for advancing military health policy

Tobacco use is the leading cause of preventable death in the United States and has been shown to significantly harm the combat readiness of military personnel. Unfortunately, recent research showed that cigarettes are sold at substantial discounts in military retail outlets. In fact, the military is the only retailer that consistently loses money on tobacco. Cheap tobacco prices have been identified by enlisted personnel and Department of Defense health policy experts as promoting a culture of tobacco use in the U.S. Military. This article provides an analysis of why current military tobacco pricing policy has failed to eliminate cheap tobacco prices as an incentive for use. A rationale for increasing tobacco prices also is presented along with recommendations for improved military tobacco control policy.

Morphological features of coronary arteries and lesions in hearts from five species of sharks collected from the northwestern Atlantic Ocean

Morphological features of coronary arteries and incidental lesions are reported from hearts in five species of sharks, the shortfin mako shark, Isurus oxyrhinchus Rafinesque, thresher shark Alopias vulpinus (Bonaterre), blue shark, Prionace glauca L., the smooth dogfish, Mustelus canis (Mitchill), and spiny dogfish, Squalus acanthias L. Sharks were collected from the northwestern Atlantic between June and August from 1996 to 2010. They were necropsied dockside and the hearts were preserved in buffered formalin. Routine sections including ventricle/conus arteriosus and the atrio-ventricular junctions were embedded in paraffin, stained with common histological and immunohistochemical methods and examined by brightfield microscopy. Myointimal hyperplasia, medial myo-myxomatous hyperplasia and bifurcation pads were observed commonly, and medial muscle reorientation and epicardial myeloid tissues were rare. All the above features differed in severity, prevalence and distribution depending on anatomical site and shark species/size. Morphometric analysis indicated that myomyxomatous hyperplasia is associated with luminal narrowing of blood vessels. As suggested previously, the described morphological features are most likely physiological responses to blood flow characteristics. Vascular and cardiac lesions were uncommon and included, granulomatous proliferative epicarditis with fibroepitheliomas, myxomatous epicardial expansions, medial arterial vacuolation, myocardial fibrosis, acute ventricular emboli and parasitic granulomas. The lesions of embolism, proliferative and granulomatous epicarditis and myocardial fibrosis were in all sharks associated with capture events including retained fishing hooks. The significance and aetiopathogenesis of medial vacuolation and epicardial myxomatous expansions remains unclear.

Military tobacco policies: the good, the bad, and the ugly

The United States military has the legacy of a pro-tobacco culture and still has prevalence rates of tobacco use that are higher than their civilian counterparts. One tactic for decreasing use and the subsequent health problems is through effective tobacco control policies. We collected available tobacco control policies from all four branches of the military and, through qualitative analysis, identified policies that were unique either as providing more or less detail and restriction than peer group policies. Best and worst practice policies in the areas of enforcement, smoking cessation, smokeless tobacco use, environmental tobacco smoke, framing tobacco as non-normative, designated tobacco use areas, and monitoring of tobacco use are presented. Because policy making can be an effective tool for improving the health of military members, understanding what policy components are comparatively positive or negative is an important tool for health advocates both in the military and civilian settings.

A content analysis of tobacco control policy in the U.S. Department of Defense

We conducted a content analysis of the US military tobacco policies at the Department of Defense, each respective military service (Army, Air Force, Navy, and Marine Corps), and their Major Commands (MAJCOM). Ninety-seven policies were evaluated using the Military Tobacco Policy Rating Form (MTPRF). More than three quarters addressed the following domains: (1) deleterious health effects of tobacco use; (2) environmental tobacco smoke; (3) designation of smoking areas; (4) tobacco prevention/cessation programs; and (5) smokeless tobacco. Few policies (2.1 per cent) mentioned relevant Department of Defense and respective service tobacco use prevalence statistics. Smoking as non-normative or incompatible with military service, the impact of tobacco use on military readiness, and the tobacco industry were addressed infrequently (6.2 per cent, 33.0 per cent, and 8.2 per cent, respectively). Future military tobacco policies should address important omissions of critical information such as the current service tobacco use prevalence, effects on readiness, and smoking as non-normative.

More help for patients trying to become tobacco-free

We must remember that we are the oral health experts. Patients must be assured of this fact. They expect us to know the facts and provide the care and advice necessary to keep their oral health in optimal condition. We have a responsibility to inform all patients that tobacco use will cause damage to their oral health. The two new resources outlined here for helping patients become tobacco-free will increase our ability to provide quality oral health care and improve oral health literacy.

Preventing 3 million premature deaths and helping 5 million smokers quit: a national action plan for tobacco cessation

In August 2002, the Subcommittee on Cessation of the Interagency Committee on Smoking and Health (ICSH) was charged with developing recommendations to substantially increase rates of tobacco cessation in the United States. The subcommittee's report, A National Action Plan for Tobacco Cessation, outlines 10 recommendations for reducing premature morbidity and mortality by helping millions of Americans stop using tobacco. The plan includes both evidence-based, population-wide strategies designed to promote cessation (e.g., a national quitline network) and a Smokers' Health Fund to finance the programs (through a 2 US dollar per pack excise tax increase). The subcommittee report was presented to the ICSH (February 11, 2003), which unanimously endorsed sending it to Secretary Thompson for his consideration. In this article, we summarize the national action plan.

The risks of oral-genital contact: a case report

Our practice of dentistry allows us the opportunity to educate our patients about the many health risks that can affect the oral cavity. Certain behaviors have the potential for serious risk to dentists and staff as well as patients and their partners. This case report details the diagnosis, treatment, and discussion of oral gonococcal infection and the need for heightened awareness among the dental population.

Migration of a maxillofacial fixation device

A case is reported of a Kirschner wire, used during orthognathic surgery (genioplasty), migrating to the floor of the mouth. After removal was attempted, the protruding portion of the wire was smoothed flush to the lingual mandibular border. Subsequent healing was uneventful.

A survey to determine the knowledge of military members about the hazards of tobacco use, and a resulting tobacco-hazard education project

A questionnaire and an intraoral examination were administered to 340 U.S. Navy personnel in order to ascertain the use of tobacco and its effect within the oral cavity. The rate of tobacco use among these military personnel was about twice that of the general public. About 45% of the patients were not well informed of the systemic or intraoral hazard of tobacco usage. With a need for tobacco-hazard awareness documented, an educational project was designed and administered to over 4,000 military and civilian participants. This education program has now been expanded to train health care professionals so that they can perform their own tobacco-hazard education with patients and small groups.