First Principles Investigation Of Substituted Strontium Hexaferrite

This dissertation investigates how the magnetic properties of strontium hexaferrite change upon the substitution of foreign atoms at the Fe sites. Strontium hexaferrite, SrFe12O19 is a commonly used hard magnetic material and is produced in large quantities (around 500,000 tons per year). For different applications of strontium hexaferrite, its magnetic properties can be tuned by a proper substitution of the foreign atoms. Experimental screening for a proper substitution is a cost-intensive and time-consuming process, whereas computationally it can be done more efficiently. We used the ‘density functional theory’ a first principles based method to study substituted strontium hexaferrite. The site occupancies of the substituted atoms were estimated by calculating the substitution energies of different configurations. The formation probabilities of configurations were used to calculate the magnetic properties of substituted strontium hexaferrite. In the first study, Al-substituted strontium hexaferrite, SrFe12-xAl x O19, with x = 0.5 and x = 1.0 were investigated. It was found that at the annealing temperature the nonmagnetic Al+3 ions preferentially replace Fe+3 ions from the 12k and 2a sites. We found that the magnetization decreases and the magnetic anisotropy field increases as the fraction, x of the Al atoms increases. In the second study, SrFe12-x Gax O19 and SrFe12-x Inx O19 with x = 0.5 and x = 1.0 were investigated. In the case of SrFe12-x Gax O19, the sites where Ga+3 ions prefer to enter are: 12k, 2a, and 4f1. For SrFe12-x Inx O19, In+3 ions most likely to occupy the 12k, 4f1, and 4f2 sites. In both cases the magnetization was found to decrease slightly as the fraction of substituted atom increases. The magnetic anisotropy field increased for SrFe12-x Gax O19, and decreased for SrFe12-x Inx O19 as the concentration of substituted atoms increased. In the third study, 23 elements (M) were screened for their possible substitution in strontium hexaferrite, SrFe12-x Mx O19 with x = 0.5. In each case the site preference of the substituted atom and the magnetic properties were calculated. We found that Bi, Ge, Sb, Sn, and Sc can effectively increase the magnetization, and Cr, P, Co, Al, Ga, and Ti can increase the anisotropy field when substituted into strontium hexaferrite

Studies on the complexes of Si(IV), Sn(IV), Ti(IV), Zr(IV) and Hf(IV) chlorides with 1, 1 Bis (Thiocyanato mercurio) ferrocene.

Silicon (IV), tin(IV), titanium(IV), Zirconium(IV) and Hofnium(IV) from 1:1 and 1:2 adducts with number of monodentate & bidentate ligands[1-5]. No attempt has been made to react ferrocene derivative with these tetravalent lewis acids. In recent years ferrocene derivatives have been used as bases[6-7] towards certain metal ions but not towards group four tetrachlorides. In this paper I present study on a new series of complexes prepared from ferrocene derivatives with tetrachlorides of Si, Sn, Ti, Zr & Hf. Â

Photoluminescence blueshift mechanisms in molecular beam epitaxy grown dilute nitride hetrostructures

Ph.DDOCTOR OF PHILOSOPH

EVALUATION OF KNOWLEDGE, PRACTICES OF VITAMIN D AND ATTITUDE TOWARDS SUNLIGHT AMONG INDIAN STUDENTS

ABSTRACTObjective: The current study was carried out to assess the knowledge, practice of Vitamin D and attitudes toward sunlight exposure among Indianstudents.Methods: We conducted a cross-sectional study on students, studying in Amity University, Noida, India. A pre-designed and self-administeredquestionnaire was given to all students to collect the information regarding their knowledge about Vitamin D.Results: Almost all (99.5%) students had heard of Vitamin D. The majority of students (53.3%) indicated that sunlight as the main source of Vitamin D,however, knowledge in terms of required daily dose and time in the sun were low among students. Despite having awareness regarding the mainsource of Vitamin D, 64.2% students did not like going in the sun and percentage (%) of female students who disliked being exposed in the sun weresignificantly higher (71.1% and 51.6%, respectively; p=0.000). Moreover, female students were a frequent user of sunscreen, applied sunscreen inboth summer and winter seasons (47.2% females vs. 37% males; p=0.000). No significant associations were found for the factors, associated with theknowledge of Vitamin D such as the use of sunscreen and hours per day outdoor.Conclusion: The findings of this survey show a lack of consistency between knowledge and attitude, negative approach toward sunlight exposuremay severely affect the Vitamin D status of young students. Implementing awareness campaigns and future health programs such as a workshop ortraining at the college level may help in building more awareness and knowledge about the Vitamin D importance.Keywords: Vitamin D, Sun exposure, Knowledge.Â

Sofosbuvir-based regimens for HCV in stage 4–stage 5 chronic kidney disease. A systematic review with meta-analysis

Background: Hepatitis C is an important agent of liver damage in patients with chronic kidney disease and the advent of DAAs has dramatically changed the management of HCV positive patients, including those with advanced CKD. Sofosbuvir is the backbone of many anti-HCV regimens based on DAAs but it remains unclear whether it is appropriate for HCV-infected patients with stage 4-5 CKD.Study aims and design: We performed a systematic review of the literature with a meta-analysis of clinical studies in order to evaluate the efficacy and safety of SOF-based DAA regimens in patients with stage 4-5 CKD. The primary outcome was sustained viral response (as a measure of efficacy); the secondary outcomes were the frequency of SAEs and drop-outs due to AEs (as measures of tolerability). The random-effects model of DerSimonian and Laird was adopted, with heterogeneity and stratified analyses.Results: Thirty clinical studies (n=1537 unique patients) were retrieved. The pooled SVR12 and SAEs rate was 0.99 (95% confidence intervals, 0.97; 1.0, I2=99.8%) and 0.09 (95% CI, 0.05; 0.13, I2=84.3%), respectively. The pooled SVR12 rate in studies with high HCV RNA levels at baseline was lower, 0.87 (95% CI, 0.75; 1.0, I2=73.3%) (P<0.001). The pooled drop-out rate due to AEs was 0.02 (95% CI, -0.01; 0.04, I2=16.1%). Common serious adverse events were anemia (n=26, 38%) and reduced eGFR (n=14, 19%). SAEs were more common in studies adopting full-dose sofosbuvir (pooled rate of SAEs 0.15, 95% CI, 0.06; 0.25; I2=80.1%) and in those based on ribavirin (0.15, 95% CI, 0.07; 0.23, I2=95.8%). Six studies (n=69 patients) reported eGFR levels at baseline/post- antiviral therapy; no consistent changes were found.Conclusions: SOF-based regimens appear safe and effective in patients with stage 4-5 CKD. Serum creatinine should be carefully monitored during therapy with SOF in patients with CKD. Randomized controlled studies in order to expand our knowledge on this point are under way.Fil: Fabrizi, Fabrizio. Ospedale Maggiore Policlinico Milano; ItaliaFil: Cerutti, Roberta. Ospedale Maggiore Policlinico Milano; ItaliaFil: Dixit, Vivek. Ospedale Maggiore Policlinico Milano; ItaliaFil: Ridruejo, Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentin

VITAMIN D; AN EVIDENCE BASED MEDICINE

Vitamin D [25OHD] is both a nutrient and hormone which provides wide variety of health benefits to human health; hence makes it unique. Vitamin D deficiency prevails all over Indian subcontinent including both urban and rural population with a prevalence rate 70%–100% in general Indian population [1]. Vitamin D deficiency leads to rickets, osteomalacia and osteoporosis.  Vitamin D also plays an important role in cardiovascular diseases, diabetes, cancer and infectious disease such as tuberculosis.  The health benefits of vitamin D are beyond bone metabolism confirmed from various studies. vitamin D not only regulate calcium metabolism but also regulates insulin production, reduces the risk of diabetes and cancer, rennin production, helps in destruction of infectious agents, regulates cell growth, enhances immunity, maintenance of vascular tone of the body, myocardial function and helps in many more complex diseases [2]. Recently, Vitamin D has received enormous attention worldwide and referred as drug of the decade. The advocacy for vitamin D supplementation would not have been done only for populations who are at risk for developing vitamin D deficiency; sensible sun exposure is an inexpensive and enjoyable way to maintain vitamin D stores. Unfortunately, it seems a paradox where majority of population is vitamin D deficient living in sunny country. Reasons to this problem are many including higher melanin content, environmental (latitude &amp; altitude), clothing pattern, food habits and genetic factors [3].  Although, Randomized controlled trials provide some low-quality evidence to support vitamin D supplementation for the reduction of asthma exacerbations in children is either limited or inconclusive with limitations such as high degree of clinical diversity (interventions and outcomes) and methodological heterogeneity (sample size and risk of bias) in included trials are challenges  [4]. Results of recent trials assessing the effect of vitamin D supplementation on the prevention of childhood acute respiratory infections (ARI) have been also inconsistent [5] and have no beneficial effect of vitamin D in improving insulin resistance was identified as well [6].  In addition vitamin D supplementation (1400 IU/ week) to low birth weight infants did not decrease the incidence of severe morbidity and mortality. (7)   On the other hand results of various studies supports the vitamin D supplementation including improvement in handgrip strength [8] increased newborn's length [9] reduces risk of maternal co-morbidities and helps improve neonatal outcomes [10]. Vitamin D requirements are probably greater in pregnancy, as evidenced by physiologically higher 1,25-dihydroxy vitamin D levels seen in the second and third trimesters. Studies recommended that vitamin D should continue to supplement in all pregnant women from the 12th week of gestation onwards [11]. Whether Vitamin D supplementation in prediabetes subjects prevents the development of diabetes is a matter of debate, and the results are inconsistent from available studies. Short-term vitamin D supplementation was found helpful in the decline of residual beta cell function (RBCF) in children with type 1 diabetes [12]. A study in subjects with pre-diabetes evaluated the effect of 12 months of Vitamin D supplementation on glycemic parameters and progression of pre-diabetes to diabetes in an ethnically homogeneous Kashmiri population, found that vitamin D supplementation helps significantly in  lowering FPG, 2-h plasma glucose and A1C levels [13]. On the other hand vitamin D supplementation (200 IU/day) did not affect plasma CRP and whole blood cytokine production of low birth weight infants (14). Study on healthy subjects also shown beneficial effect that were supplemented with cholecalciferol at a dose of 60,000 IU/week for 12 weeks resulted in improvement in the skeletal muscle energy metabolism[15].  Oral dose of vitamin D can be easily distributed among populations. However, 1000 IU of vitamin D/day has shown better results than 60, 000 IU/week in populations but it will be difficult to feed 1000 IU/Day to populations due to logistics issues. So, 60,000 IU/ week up to 8 weeks then once a month may be chosen as a dose schedule in populations [16]. Moreover, the usual calcium pill contains 200 IU of vitamin D and 2 pills a day equals 400 IU/day which is grossly inadequate. To achieve optimal serum 25 (OH) D levels i.e. 30 ng/ml in population; 2000 IU of vitamin D/day is required [17] thus at present it may be safest to adhere to 2000 IU/day as a standard practice in India. Indian studies regarding vitamin D supplementation including pregnant women [18], Young women [19] and asian Indians [20] already shown beneficial effect. Studies in animal models show plausible evidence in favour of vitamin D as an anti-inflammatory agent and a viable option for treatment of anti- inflammatory disease i.e crohn's disease (CD). Epidemiological and cross sectional studies indicate that vitamin D may have a potential of treating CD in humans [21]. Recent findings from various studies provide evidence of a possible beneficial effect of vitamin D supplementation in patients with early Parkinson's disease [22], respiratory tract infections [23] chronic heart disease (CHD) [24] and also helps in strengthening femoral neck (FN) in a dose-dependent manner, especially in women [25]. In a recent study we have shown improvement in bone health after vitamin D supplementation in patients with hyperthyroidism [26].  Hence, we propose that vitamin D may be used as evidence based medicine in clinical practice. This will also helpful in mitigating the growing burden of communicable and non-communicable diseases in India. The health benefits of vitamin D are beyond bone metabolism confirmed from various studies. vitamin D not only regulate calcium metabolism but also regulates insulin production, reduces the risk of diabetes and cancer, rennin production, helps in destruction of infectious agents, regulates cell growth, enhances immunity, maintenance of vascular tone of the body, myocardial function and helps in many more complex diseases [2]. Recently, Vitamin D has received enormous attention worldwide and referred as drug of the decade. The advocacy for vitamin D supplementation would not have been done only for populations who are at risk for developing vitamin D deficiency; sensible sun exposure is an inexpensive and enjoyable way to maintain vitamin D stores. Unfortunately, it seems a paradox where majority of population is vitamin D deficient living in sunny country. Reasons to this problem are many including higher melanin content, environmental (latitude &amp; altitude), clothing pattern, food habits and genetic factors [3].  Although, Randomized controlled trials provide some low-quality evidence to support vitamin D supplementation for the reduction of asthma exacerbations in children is either limited or inconclusive with limitations such as high degree of clinical diversity (interventions and outcomes) and methodological heterogeneity (sample size and risk of bias) in included trials are challenges  [4]. Results of recent trials assessing the effect of vitamin D supplementation on the prevention of childhood acute respiratory infections (ARI) have been also inconsistent [5] and have no beneficial effect of vitamin D in improving insulin resistance was identified as well [6].  In addition vitamin D supplementation (1400 IU/ week) to low birth weight infants did not decrease the incidence of severe morbidity and mortality. (7)   On the other hand results of various studies supports the vitamin D supplementation including improvement in handgrip strength [8] increased newborn's length [9] reduces risk of maternal co-morbidities and helps improve neonatal outcomes [10]. Vitamin D requirements are probably greater in pregnancy, as evidenced by physiologically higher 1,25-dihydroxy vitamin D levels seen in the second and third trimesters. Studies recommended that vitamin D should continue to supplement in all pregnant women from the 12th week of gestation onwards [11]. Whether Vitamin D supplementation in prediabetes subjects prevents the development of diabetes is a matter of debate, and the results are inconsistent from available studies. Short-term vitamin D supplementation was found helpful in the decline of residual beta cell function (RBCF) in children with type 1 diabetes [12]. A study in subjects with pre-diabetes evaluated the effect of 12 months of Vitamin D supplementation on glycemic parameters and progression of pre-diabetes to diabetes in an ethnically homogeneous Kashmiri population, found that vitamin D supplementation helps significantly in  lowering FPG, 2-h plasma glucose and A1C levels [13]. On the other hand vitamin D supplementation (200 IU/day) did not affect plasma CRP and whole blood cytokine production of low birth weight infants (14). Study on healthy subjects also shown beneficial effect that were supplemented with cholecalciferol at a dose of 60,000 IU/week for 12 weeks resulted in improvement in the skeletal muscle energy metabolism[15].  Oral dose of vitamin D can be easily distributed among populations. However, 1000 IU of vitamin D/day has shown better results than 60, 000 IU/week in populations but it will be difficult to feed 1000 IU/Day to populations due to logistics issues. So, 60,000 IU/ week up to 8 weeks then once a month may be chosen as a dose schedule in populations [16]. Moreover, the usual calcium pill contains 200 IU of vitamin D and 2 pills a day equals 400 IU/day which is grossly inadequate. To achieve optimal serum 25 (OH) D levels i.e. 30 ng/ml in population; 2000 IU of vitamin D/day is required [17] thus at present it may be safest to adhere to 2000 IU/day as a standard practice in India. Indian studies regarding vitamin D supplementation including pregnant women [18], Young women [19] and asian Indians [20] already shown beneficial effect. Studies in animal models show plausible evidence in favour of vitamin D as an anti-inflammatory agent and a viable option for treatment of anti- inflammatory disease i.e crohn's disease (CD). Epidemiological and cross sectional studies indicate that vitamin D may have a potential of treating CD in humans [21]. Recent findings from various studies provide evidence of a possible beneficial effect of vitamin D supplementation in patients with early Parkinson's disease [22], respiratory tract infections [23] chronic heart disease (CHD) [24] and also helps in strengthening femoral neck (FN) in a dose-dependent manner, especially in women [25]. In a recent study we have shown improvement in bone health after vitamin D supplementation in patients with hyperthyroidism [26]. Hence, we propose that vitamin D may be used as evidence based medicine in clinical practice. This will also helpful in mitigating the growing burden of communicable and non-communicable diseases in India

Race affects SVR12 in a large and ethnically diverse hepatitis C-infected patient population following treatment with direct-acting antivirals: Analysis of a single-center Department of Veterans Affairs cohort.

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease. HCV cure has been linked to improved patient outcomes. In the era of direct-acting antivirals (DAAs), HCV cure has become the goal, as defined by sustained virological response 12&nbsp;weeks (SVR12) after completion of therapy. Historically, African-Americans have had lower SVR12 rates compared to White people in the interferon era, which had been attributed to the high prevalence of non-CC interleukin 28B (IL28B) type. Less is known about the association between race/ethnicity and SVR12 in DAA-treated era. The aim of the study is to evaluate the predictors of SVR12 in a diverse, single-center Veterans Affairs population. We conducted a retrospective study of patients undergoing HCV therapy with DAAs from 2014 to 2016 at the VA Greater Los Angeles Healthcare System. We performed a multivariable logistic regression analysis to determine predictors of SVR12, adjusting for age, HCV genotype, DAA regimen and duration, human immunodeficiency virus (HIV) status, fibrosis, nonalcoholic fatty liver disease (NAFLD) fibrosis score, homelessness, mental health, and adherence. Our cohort included 1068 patients, out of which 401 (37.5%) were White people and 400 (37.5%) were African-American. Genotype 1 was the most common genotype (83.9%, N&nbsp;=&nbsp;896). In the adjusted models, race/ethnicity and the&nbsp;presence of fibrosis were statistically significant predictors of non-SVR. African-Americans had 57% lower odds for reaching SVR12 (adj.OR&nbsp;=&nbsp;0.43, 95% CI&nbsp;=&nbsp;1.5-4.1) compared to White people. Advanced fibrosis (adj.OR&nbsp;=&nbsp;0.40, 95% CI&nbsp;=&nbsp;0.26-0.68) was also a significant predictor of non-SVR. In a single-center VA population on DAAs, African-Americans were less likely than White people to reach SVR12 when adjusting for covariates

Complete Remission in Newly Diagnosed Type 1 Diabetes Mellitus Patient

Type 1 diabetes mellitus is a chronic disease affects pancreatic beta cells. Usually it has a life long duration, however, in few cases, it can be transient. We reported a 20 year old male patient who visited the diabetic clinic of Lok Nayak Hospital with classical symptoms of type 1 diabetes mellitus. He was diagnosed with type 1 diabetes on the basis of lab parameters. He was found to be positive for ICA512 and GAD antibodies. Measurement of C-peptide was also done by mixed meal tolerance test. Initially, Insulin was advised to control hyperglycemia. After 2 weeks, he was given 14 infusions of Teplizumab injection, one infusion per day and the same has been repeated after six months. As per clinical judgment, it was assumed that he was not on placebo arm and probably received Teplizumab as investigational product. Teplizumab injection drastically reduces the insulin doses and after some time, his insulin was completely waived off. Complete remission was seen in this patient after treatment with Teplizumab injection. During the 4 years follow-up, this remission is still ongoing in this patient. He had normal fasting and home blood glucose concentration with normal HbA1c without insulin therapy from last 4 years. To keep his blood sugar values under control, patient was also advised regular exercise and a diabetic diet