Effectiveness of eye armor during blast loading

Ocular trauma is one of the most common types of combat injuries resulting from the interaction of military personnel with improvised explosive devices. Ocular blast injury mechanisms are complex, and trauma may occur through various injury mechanisms. However, primary blast injuries (PBI) are an important cause of ocular trauma that may go unnoticed and result in significant damage to internal ocular tissues and visual impairment. Further, the effectiveness of commonly employed eye armor, designed for ballistic and laser protection, in lessening the severity of adverse blast overpressures (BOP) is unknown. In this paper, we employed a three-dimensional (3D) fluid-structure interaction computational model for assessing effectiveness of the eye armor during blast loading on human eyes and validated results against free field blast measurements by Bentz and Grimm (2013). Numerical simulations show that the blast waves focused on the ocular region because of reflections from surrounding facial features and resulted in considerable increase in BOP. We evaluated the effectiveness of spectacles and goggles in mitigating the pressure loading using the computational model. Our results corroborate experimental measurements showing that the goggles were more effective than spectacles in mitigating BOP loading on the eye. Numerical results confirmed that the goggles significantly reduced blast wave penetration in the space between the armor and the eyes and provided larger clearance space for blast wave expansion after penetration than the spectacles. The spectacles as well as the goggles were more effective in reducing reflected BOP at higher charge mass because of the larger decrease in dynamic pressures after the impact. The goggles provided greater benefit of reducing the peak pressure than the spectacles for lower charge mass. However, the goggles resulted in moderate, sustained elevated pressure loading on the eye, that became 50-100 % larger than the pressure loading experienced by the unprotected eye after 0.2 ms of impact of blast wave, for lower as well as higher charge mass. The present model provides fundamental insights of flow and pressure fields in the ocular region, which helps to explain the effectiveness of the eye armor. Since the measurements of these fields are not trivial, the computational model aids in better understanding of development of PBI

Comparison of Oral Health Indicators in Type 2 Diabetes Mellitus Patients and Controls

Introduction India leads the world with largest number of diabetic subjects earning the dubious distinction of being termed the ′diabetes capital of the world′. Oral manifestations of diabetes mellitus are devastating, these include gingival and periodontal diseases, bone loss, dental caries, alterations in salivary flow and others. Materials and methods: In our study, sample consists of 50 patients with type 2 diabetes mellitus (study group) and 50 nondiabetic patients (control group) of age range of 35 to 70 years. The oral indicators used in the study are orthopantomogram, decayed-missing-filled teeth index, oral hygiene index-simplified, periodontal index, gingival index, body mass index, waist circumferences, fasting blood sugar, postprandial glucose and random fasting blood sugar should be replaced by random blood sugar. Results: In our study, statistically body mass index (p < 0.01), waist circumference (p < 0.001), periodontal disease index (p < 0.01), gingival index (p < 0.01) and bone loss (p < 0.001) were higher in diabetic group than nondiabetic group and were significant. And, periodontal index of smokers is significantly higher than compared with nonsmokers diabetic patients. Conclusion: The results of present study demonstrate that gingival index, periodontal index and bone loss measurements in diabetic patients are significantly higher than nondiabetic patients. Smoking is also a promoting factor of periodontal disease in diabetic patients