Scaling Law for Criticality Conditions in Heterogeneous Energetic Materials under Shock Loading

Initiation in heterogeneous energetic material (HEM) subjected to shock loading occurs due to the formation of hot spots. The criticality of the hot spots governs the initiation and sensitivity of HEMs. In porous energetic materials, collapse of pores under impact leads to the formation of hot spots. Depending on the size and strength of the hot spots chemical reaction can initiate. The criticality of the hot spots is dependent on the imposed shock load, void morphology and the type of energetic material. This work evaluates the relative importance of material constitutive and reactive properties on the criticality condition of spots. Using a scaling-based approach, the criticality criterion for cylindrical voids as a function of shock pressure, Ps and void diameter, Dvoid is obtained for two different energetic material HMX and TATB. It is shown that the criticality of different energetic materials is significantly dependent on their reactive properties

Evaluation of simplified acute physiology score 3 performance: a systematic review of external validation studies

Introduction: Simplified Acute Physiology Score 3 (SAPS 3) was the first critical care prognostic model developed from worldwide data. We aimed to systematically review studies that assessed the prognostic performance of SAPS 3 general and customized models for predicting hospital mortality in adult patients admitted to the ICU. Methods: Medline, Lilacs, Scielo and Google Scholar were searched to identify studies which assessed calibration and discrimination of general and customized SAPS 3 equations. Additionally, we decided to evaluate the correlation between trial size (number of included patients) and the Hosmer-Lemeshow (H-L) statistics value of the SAPS 3 models. Results: A total of 28 studies were included. Of these, 11 studies (42.8\%) did not find statistically significant mis-calibration for the SAPS 3 general equation. There was a positive correlation between number of included patients and higher H-L statistics, that is, a statistically significant mis-calibration of the model (r = 0.747, P < 0.001). Customized equations for major geographic regions did not have statistically significant departures from perfect calibration in 9 of 19 studies. Five studies (17.9\%) developed a regional customization and in all of them this new model was not statistically different from a perfect calibration for their populations. Discrimination was at least very good in 24 studies (85.7\%). Conclusions: Statistically significant departure from perfect calibration for the SAPS 3 general equation was common in validation studies and was correlated with larger studies, as should be expected, since H-L statistics (both C and H) are strongly dependent on sample size This finding was also present when major geographic customized equations were evaluated. Local customizations, on the other hand, improved SAPS 3 calibration. Discrimination was almost always very good or excellent, which gives excellent perspectives for local customization when a precise local estimate is needed.publishersversionpublishe

Role of expression of atrial natriuretic peptide gene in essential hypertension among Egyptian patients

Introduction: Essential Hypertension has been a great burden on public health services for a long time, with many life-threatening complications. Therefore, we decided to study Atrial Natriuretic peptide (ANP) gene expression as one of the most important blood pressure controlling genes, in order to use ANP gene as a potential diagnostic or therapeutic marker in the near future.Methods: One hundred essential hypertensive patients and 100 normotensive controls were included. Study Subjects were subjected to ANP gene expression analysis, together with blood pressure measurement, Lab investigations, and BMI analysis.Results: There was a statistical difference between ANP gene expression and blood pressure, with lower ANP gene expression level (median of 0.3) being present among hypertensive patients and higher ANP gene expression level (median of 1.6) among normotensive controls (p &lt; 0.001).Discussion: We proved that ANP gene expression to be low in essential hypertension patients compared with normotensive individuals

Locked-In with COVID-19

© 2020 Elsevier Ltd Coronavirus Disease 2019 (COVID-19) can be associated with various neurological manifestations including acute strokes. Hyper acute diagnosis and treatment are key factors which decrease mortality and morbidity in stroke patients. The COVID-19 pandemic has introduced a great strain on the healthcare system, and as a result clinicians are facing several barriers in diagnosing and treating strokes. Delayed presentation of strokes is a problem as some in the general population defer the decision to seek immediate medical attention fearing contracting the virus. Also playing a role is the paucity of healthcare professionals available during a pandemic. Recent literature demonstrates the association of acute strokes in young patients with COVID-19. Lack of clear pathophysiology of the neurological manifestations from COVID-19 intensifies the problem. A thorough examination of the intensive care unit patient has always been a challenge owing to several factors including use of sedatives, sepsis, uremia, and encephalopathy secondary to medications. Locked-In Syndrome (LIS) secondary to stroke is much more challenging to diagnose as patients are unable to communicate or elicit any motor functions apart from certain ocular movements. We present the case of a 25 year old patient with no known history of coagulopathy, but had developed COVID-19 cytokine storm which culminated in LIS secondary to pontine strokes