Environmentally-induced discharge transient coupling to spacecraft

The Hughes SCREENS (Space Craft Response to Environments of Space) technique was applied to generic spin and 3-axis stabilized spacecraft models. It involved the NASCAP modeling for surface charging and lumped element modeling for transients coupling into a spacecraft. A differential voltage between antenna and spun shelf of approx. 400 V and current of 12 A resulted from discharge at antenna for the spinner and approx. 3 kv and 0.3 A from a discharge at solar panels for the 3-axis stabilized Spacecraft. A typical interface circuit response was analyzed to show that the transients would couple into the Spacecraft System through ground points, which are most vulnerable. A compilation and review was performed on 15 years of available data from electron and ion current collection phenomena. Empirical models were developed to match data and compared with flight data of Pix-1 and Pix-2 mission. It was found that large space power systems would float negative and discharge if operated at or above 300 V. Several recommendations are given to improve the models and to apply them to large space systems

Toxicological Significance of Silicon-protein Interaction

In order to understand the molecular mechanism of the toxicity of Si containing particulate air pollutants, the interaction between silicate anion and proteins was studied. On the basis of molecular sieving profile, the presence of a protein fraction capable of binding silicic acid was detected in rat lung and serum. The binding is firm being able to withstand dialysis, Si-binding by Bovine Serum Albumin (BSA) follows stoichiometric principles indicating true chemical reaction in terms of effects of pH, temperature and period of incubation. Fluorescence spectrum of the BSA-Si complex decreased with an increase in Si concentration. Effect of Si-binding on trypsin activity against albumin showed that proteins other than albumin could also interact with Si-trypsin containing silica showed distinctly low, catalytic activity against native BSA. When both the substrate and enzyme contained bound Si, the activity further reduced by 36 per cent as compared to both pure trypsin and pure BSA, clearly indicating that binding of Si with substrate or enzyme proteins can adversely effect the biological activity. Complexing with proteins is likely to play a role in pathogenesis of pneumoconiosis, elimination of dusts, formation of silicate stones in plants and animals, and possibly in the reported role of Si in nutrition, cardiovascular diseases and ageing

W-band sparse synthetic aperture for computational imaging

journal articleWe present a sparse synthetic-aperture, active imaging system at W-band (75 - 110 GHz), which uses sub-harmonic mixer modules. The system employs mechanical scanning of the receiver module position, and a fixed transmitter module. A vector network analyzer provides the back end detection. A full-wave forward model allows accurate construction of the image transfer matrix. We solve the inverse problem to reconstruct scenes using the least squares technique. We demonstrate far-field, diffraction limited imaging of 2D and 3D objects and achieve a cross-range resolution of 3 mm and a depth-range resolution of 4 mm, respectively. Furthermore, we develop an information-based metric to evaluate the performance of a given image transfer matrix for noise-limited, computational imaging systems. We use this metric to find the optimal gain of the radiating ele­ ment for a given range, both theoretically and experimentally in our system

Mother mouse sets the circadian clock of pups

We report here the ontogeny of a circadian clock of the field mouseMus booduga expressing itself 16 days after parturition in the locomotory activity of neonate pups removed from the mother and held in continuous darkness ever since birth. Locomotion is a 'complex' activity serving such functions as foraging, exploration, and territoriality. Since these functions are not conventionally associated with neonate and altricial animals, it is of interest that this ability has such an early circadian origin. A backward extrapolation of the pups rhythm and the rhythm of the mother strongly implicate maternal synchronization. The period of the circadian rhythm of the pups shortens with age, from birth up to six months

Continuous light abolishes the maternal entrainment of the circadian activity rhythm of the pups in the field mouse

12:12-h cycles of presence and absence of mother mouse act as a 'zeitgeber' and entrain the circadian rhythm of locomotor activity in the pups ofMus booduga under continuous darkness or continuous dim light. Continuous higher illumination of 15-25 lx abolishes this impressive maternal entrainment

Concurrent Chemoradiation for Vaginal Cancer

Background: It is not known whether the addition of chemotherapy to radiation therapy improves outcomes in primary vaginal cancer. Here, we review clinical outcomes in patients with primary vaginal cancer treated with radiation therapy (RT) or concurrent chemoradiation therapy (CRT). Methods: Seventy-one patients with primary vaginal cancer treated with definitive RT with or without concurrent chemotherapy at a single institution were identified and their records reviewed. A total of 51 patients were treated with RT alone; 20 patients were treated with CRT. Recurrences were analyzed. Overall survival (OS) and disease-free survival (DFS) rates were estimated using the Kaplan-Meier method. Cox regression analysis was performed. Results: The median age at diagnosis was 61 years (range, 18–92 years) and the median follow-up time among survivors was 3.0 years. Kaplan-Meier estimates for OS and DFS differed significantly between the RT and CRT groups (3-yr OS = 56% vs. 79%, log-rank p = 0.037; 3-yr DFS = 43% vs. 73%, log-rank p = 0.011). Twenty-three patients (45%) in the RT group had a relapse at any site compared to 3 (15%) in the CRT group (p = 0.027). With regard to the sites of first relapse, 10 patients (14%) had local only, 4 (6%) had local and regional, 9 (13%) had regional only, 1 (1%) had regional and distant, and 2 (3%) had distant only relapse. On univariate analysis, the use of concurrent chemotherapy, FIGO stage, tumor size, and date of diagnosis were significant predictors of DFS. On multivariate analysis, the use of concurrent chemotherapy remained a significant predictor of DFS (hazard ratio 0.31 (95% CI, 0.10–0.97; p = 0.04)). Conclusions: Vaginal cancer results in poor outcomes. Adequate radiation dose is essential to ensure curative management. Concurrent chemotherapy should be considered for vaginal cancer patients

Report of the Marine Protected Areas Working Group meeting, Penang, Malaysia, 11-12 February, 2014

The objectives of the workshop were to review and update Marine Protected Area (MPA) data, finalise policy briefs for each country and recommend future actions and policies for sustainable management of MPAs

Newer echocardiographic parameters in assessing RV and LV function in patients with corpulmonale.

In India still pulmonary tuberculosis is prevalent and stays as one of the leading cause of death. The cause of the death in most of the terminally ill pulmonary tuberculosis patient is corpulmonale and related cardiac problem. With the increase in incidence of retro viral infection and diabetes the prevalence of multi drug resistant pulmonary tuberculosis is high .This leads to increase in the chances for the corpulmonale. In the rural areas poverty and malnutrition lead to increased incidence and prevalence of tuberculosis. In the urban areas exposure to the automobile gases and dust particles predisposes patients to pulmonary diseases and COPD in later life. COPD in the later stages lead to right ventricular dilatation and corpulmonale. The development and implementation of the national programs for the detection and treatment of the tuberculosis is trying to treat the disease in the early stage itself to prevent such corpulmonale in future. In this study we are going to find easy solution to diagnose the lung disease related cardiac problem in the early stage itself without making mistakes. In corpulmonale patients right ventricular systolic dysfunction is recognized to occur and it has been proved in many studies. But the corpulmonale patients are symptomatic not only because of the lung pathology and right heart failure, but also due to left ventricular dysfunction in the form of left ventricular systolic and left ventricular diastolic dysfunction .The dilated right ventricle pushes the interventricular septum towards left ventricle and interferes with left ventricular filling, which lead onto diastolic dysfunction of left ventricle. The additional metabolic factors like hypoxia, hypercapnea and acidosis lead on to direct myocardial depressant action and produce myocardial dysfunction in both left and right ventricle. AIMS & OBJECTIVES 1. To study the utility of newer echocardiographic parameters like mitral annular plane systolic excursion, mitral annular systolic velocity, tricuspid annular plane systolic excursion, tricuspid annular systolic velocity, and ‘e’ propagation velocity in identifying right ventricular systolic ,left ventricular systolic and diastolic dysfunction in patients with corpulmonale. 2. To study the prevalence of right ventricular systolic, left ventricular systolic and left ventricular diastolic dysfunction in patients with corpulmonale. CONCLUSION: 1. Left ventricular diastolic dysfunction occurred in about 50% of the corpulmonale patients. 2. Left ventricular systolic dysfunction was observed in 10-20% percent in the study which is higher than the published literature. 3. MAPSE and MASV are simple and useful parameter to assess the left ventricular systolic dysfunction. 4. TAPSE and TASV are simple and useful index in corpulmonale patients to assess right ventricular systolic dysfunction. 5. It is found that atleast some amount of right ventricular systolic dysfunction was detected when the newer echocardiographic parameters were used in most of the corpulmonale patients

A Study on the prevalence of Asymptomatic Ischemic Heart Disease in Diabetic Women and association of Cardiac Autonomic Neuropathy with Silent Myocardical Ischemia

INTRODUCTION: Patients with diabetes have a 2-4 fold increase in risk of CAD. Better implementation of therapies that reduce cardiovascular risk in diabetic patients will require moving beyond the traditional primary focus on glycaemic control. A working knowledge of the effects of diabetes mellitus on the heart & blood vessels will aid physicians caring for these patients. In general population women experience relative protection from myocardial infarction and usually develop CAD approximately 10 years later than men. However diabetes blunts the cardiovascular benefit of female gender. In the first national health & nutrition examination survey (NHANES) & the NHANES epidemiologic follow up survey conducted 10 years apart, age adjusted mortality decreased in non-diabetic men & women, less so in diabetic men, but increased by 23% in diabetic women. In the Gruppo Italino per 10 studio della sopravvivenza bell Intarto miocardio – 2 (GISSI – 2) study of thrombolytic therapy in patients with myocardial infarction, diabetes increased the rate of death in men by 40% and women by 90%. Diabetic Autonomic neuropathy is the most common and troublesome complication of type 2 Diabetes mellitus. Cardiovascular Autonomic neuropathy is a common form of Autonomic neuropathy causing abnormalities in heart rate control, central and peripheral vascular dynamics. Cardiac autonomic neuropathy has been linked to postural hypotension, exercise tolerance, enhanced intra operative cardiovascular lability, increased incidence of asymptomatic ischemia, myocardial infarction and decreased likelihood of survival after myocardial infarction. Hypothesis concerning the multiple etiologies of diabetic neuropathy include metabolic insult to nerve fibers, neurovascular insufficiency, autoimmune damage and neuro-humoral growth factor deficiency. Cardiac autonomic neuropathy which is considered to be a cause for asymptomatic CAD in diabetics is tested by history and simple bedside tests. Its presence has been correlated with the silent myocardial ischemia. AIM OF THE STUDY: 1. To study the prevalence of asymptomatic ischemic heart disease in diabetic women by exercise stress test. 2. To correlate the presence of cardiac autonomic neuropathy with the asymptomatic ischemic heart disease. MATERIALS AND METHODS: Place of Study: Institute of Internal Medicine, Madras Medical College & Government General Hospital, Chennai. Study Population: Of the 107 patients enrolled for the study who attended out patient clinic of institute of internal medicine, Government General Hospital, 30 patients were selected for the treadmill test and presence of cardiac autonomic neuropathy in them was tested by history and simple bed side tests. Other 77 patients are excluded as per exclusion criteria. Inclusion Criteria: 1. Known diabetic women on treatment (OHA & insulin therapy), 2. Diabetic women not on treatment for CAD, 3. Patients not on beta blockers, 4. Duration of diabetes within 10 years, 5. Echocardiography normal. Exclusion Criteria: 1. Patients with peripheral vascular disease as evidenced by absent peripheral pulses, 2. Type 1 diabetes mellitus, 3. Known case of coronary artery disease, 4. Signs of left ventricular failure, 5. Uncontrolled systemic hypertension, 6. High risk unstable angina, 7. Age > 65 yrs, 8. Other absolute contraindications for exercise stress test. STATISTICAL ANALYSIS: Statistical analysis was carried for 30 subjects after categorizing each variable. Autonomic neuropathy bedside tests are performed for all the patients. Age, duration of diabetes, BMI, systemic hypertension, menopause and percentage of CAN positivity in TMT positive and negative group were analyzed. The significance of difference in mean between means were calculated using z test and difference in proportions using chi-square statistic. Statistical significance is taken when P < 0.05. Statistical analysis was carried out using standard formulae. Microsoft excel 2003 and SPSS (statistical package for social sciences) version 13.0 softwares were used for data entry and analysis. CONCLUSION: 1. The prevalence of asymptomatic ischemic heart disease was higher in diabetic women when compared to non diabetics. About one third of diabetic women are having asymptomatic ischemic heart disease which can be detected by simple treadmill test. 2. Prevalence of cardiac autonomic neuropathy was higher in treadmill positive patients who are otherwise asymptomatic. This shows that there is significant association between silent myocardial ischemia and cardiac autonomic neuropathy in diabetic population. 3. Poor exercise capacity was noted in the TMT positive but otherwise asymptomatic diabetic women

Lowest log canonical thresholds of a reduced plane curve of degree <i>d</i>

We describe the sixth worst singularity that a plane curve of degree d⩾ 5 could have, using its log canonical threshold at the point of singularity. This is an extension of a result due to Cheltsov (J Geom Anal 27(3):2302–2338, 2017) wherein the five lowest values of log canonical thresholds of a plane curve of degree d⩾ 3 were computed. These six small log canonical thresholds, in order, are 2 / d, (2 d- 3 ) / (d- 1 ) 2, (2 d- 1 ) / (d2- d) , (2 d- 5 ) / (d2- 3 d+ 1 ) , (2 d- 3 ) / (d2- 2 d) and (2 d- 7 ) / (d2- 4 d+ 1 ). We give examples of curves with these values as their log canonical thresholds using illustrations