Spurious Grain Formation During Directional Solidification in Microgravity

This research is aimed at carrying out a systematic investigation of the nucleation, and growth of spurious “misoriented” grains during directional solidification in the low gravity environment of space. Three Al–7 wt. % Si alloy cylindrical samples (MICAST-6, MICAST-7 and MICAST2-12) were directionally solidified on the Space Station at growth speeds varying from 5 to 50 µms-1 under thermal gradients varying from 14 to 33 K cm-1 in alumina crucibles, under a joint NASA-ESA (European Space Agency) project called, MICAST (Microstructure formation in casting of technical alloys under a diffusive and magnetically controlled convection conditions). The primary purpose of directionally solidifying these three Al-7Si samples in the low gravity environment of space was to eliminate gravity-induced convection in the melt, and grow dendrite array morphology under purely diffusive transport conditions. However, when these directionally solidified samples were extracted from their alumina crucibles, they all showed evidence of surface pores along their length. We believe that these pores formed because in microgravity, there is no imposed force to pull the liquid column down on to the solidifying portion below to continue to feed the volume shrinkage due to liquid to solid phase transformation. There was no additional built-in mechanism, such as a piston and spring, in the MICAST ampoules to keep the melt column pressed onto the solid below. We also believe that even in the absence of gravity, a liquid coulmn which gets detached from the crucible internal waals (forming surface pores), under an imposed positive thermal gradient, would lead to the liquid-solid surface energy driven Marangoni convection. This convection may fragment fragile secondary or tertiary arms of the primary dendrite trees growing in the mushy zone. These broken dendrite solid fragments may lead to the nucleation and growth of spurious grains in the MICAST samples, where the orientation of primary dendrites would be very different from those in their unmelted seed portions. Our purpose is to examine the longitudinal and transverse microstructures of these MICAST samples to study the formation of spurious grains, and investigate if there is any correlation between the location of the observed surface pores and the formation of spurious grains

Spurious Grain Formation During Directional Solidification in Microgravity

This research is aimed at carrying out a systematic investigation of the nucleation, and growth of spurious “misoriented” grains during directional solidification in the low gravity environment of space. Three Al–7 wt. % Si alloy cylindrical samples (MICAST-6, MICAST-7 and MICAST2-12) were directionally solidified on the Space Station at growth speeds varying from 5 to 50 µms-1 under thermal gradients varying from 14 to 33 K cm-1 in alumina crucibles, under a joint NASA-ESA (European Space Agency) project called, MICAST (Microstructure formation in casting of technical alloys under a diffusive and magnetically controlled convection conditions). The primary purpose of directionally solidifying these three Al-7Si samples in the low gravity environment of space was to eliminate gravity-induced convection in the melt, and grow dendrite array morphology under purely diffusive transport conditions. However, when these directionally solidified samples were extracted from their alumina crucibles, they all showed evidence of surface pores along their length. We believe that these pores formed because in microgravity, there is no imposed force to pull the liquid column down on to the solidifying portion below to continue to feed the volume shrinkage due to liquid to solid phase transformation. There was no additional built-in mechanism, such as a piston and spring, in the MICAST ampoules to keep the melt column pressed onto the solid below. We also believe that even in the absence of gravity, a liquid coulmn which gets detached from the crucible internal waals (forming surface pores), under an imposed positive thermal gradient, would lead to the liquid-solid surface energy driven Marangoni convection. This convection may fragment fragile secondary or tertiary arms of the primary dendrite trees growing in the mushy zone. These broken dendrite solid fragments may lead to the nucleation and growth of spurious grains in the MICAST samples, where the orientation of primary dendrites would be very different from those in their unmelted seed portions. Our purpose is to examine the longitudinal and transverse microstructures of these MICAST samples to study the formation of spurious grains, and investigate if there is any correlation between the location of the observed surface pores and the formation of spurious grains

Low cycle fatigue and post fatigue tensile behavior of a non-conventional austenitic stainless steel

Traditionally, stainless steels find a wide range of applications, which include pipelines, automobiles, engine and gear parts etc. In many of these applications, structures and components go through fatigue loading ranging for low cycle to high cycle. ISO/TR 15510 X12CrMnNiN17-7-5 is a special grade of austenitic stainless steel, which is developed to conserve nickel and is used in automobile parts such as automotive trim, automobile wheel covers, flat conveyer chains, railroad passenger car bodies. The aim of this project is to explore the low cycle fatigue behaviour and its effect on the tensile properties of the abovementioned non-conventional stainless steel, which is unavailable in literature. Attempts have also been made to understand the microstructural variation due to deformation in the steel, as the structure is austenitic, hence metastable in nature. For these purposes a set of non-conventional austenitic stainless steel rods were annealed by soaking at 1000°C for one hour these were followed by water quenching prior to machining.The fatigue studies have been carried out at four different strain amplitudes (at ambient temperature) up to 100 cycles, which have been followed by tensile tests on the fatigued samples at constant crosshead speed of 1mm/minute. The low cycle fatigue results include that the steel undergoes cyclic softening behavior, which has also been reflected from the post-fatigue tensile results X-ray diffraction studies indicate that deformation induced phase transformation takes place in the steel due to combined effects of fatigue and tensile loading. The extent of phase transformation has been estimated and is correlated with the extent of deformation

In vitro anti-estrogenic potential of FertiZen-R™- a nutraceutical ingredient for estrogen modulation

Background: According to CDC, polycystic ovarian syndrome (PCOS) is responsible for infertility in women with 6-12% incidences all over the world. The current treatment options available have several side effects such as amenorrhea and obesity amongst others. Dietary interventions such as non-estrogenic and androgen-suppressing foods along with nutraceutical products is considered for treating PCOS with minimum side effects. One such product of Zenherbs lab called FertiZen-R™ is a combination of three phytochemicals from three plants viz., Foeniculum vulgare, Linum Usitatissimum, Glycyrrhiza glabra, hibiscus extract and is developed as a product to treat and control PCOS. Methods: The FertiZen-R™ was quantified for the presence of phytochemicals such as glycyrrhizic acid, polyphenols, and saponins. It was further tested for estrogenic/anti-estrogenic potential on estrogen-positive breast cancer cell line (MCF-7) using an E-Screen assay. Results: The FertiZen-R™ showed presence of 5% glycyrrhizinic acid, 5% saponins, and 2-3% polyphenols. It exhibited a strong anti-estrogenic potential with 40-50% inhibition from concentrations as low as 0.156 mg/ml like tamoxifen (IC50 at 0.156 mg/ml), while inositol, a natural growth promoter, showed no effect on the cell viability. Conclusions: FertiZen-R™ showed anti-estrogenic potential when tested in-vitro and can be used to treat PCOS in women even with ER-positive breast cancer cells. However, clinical studies to determine the dosage are required to warrant the potential of FertiZen-R™

Detection of Anti- Leptospira

Leptospirosis is a globally distributed zoonosis with varied clinical outcomes and multiorgan involvement in humans. In this study conducted from July 2011 to December 2011, 178 serum samples from patients suspected of leptospirosis were tested by Panbio IgM ELISA at National Public Health Laboratory, Kathmandu, out of which 51 (28.65%) were positive for anti-Leptospira IgM antibody. Leptospirosis was more common in people in their 2nd and 3rd decades of their life which together comprised 56.86% of the total positive cases. Most of those tested positive were farmers followed by students and housewives. Both animal contact and water contact seemed to play significant roles in disease transmission. Symptoms were vague with the most common being fever, headache, myalgia, abdominal pain, vomiting, jaundice, and diarrhoea. Life style heavily dominated by agronomical and farming activities in Nepal is conducive to leptospirosis transmission. Leptospirosis seems to be a significant public health problem in Nepal but is underestimated. In resource poor countries like Nepal where laboratories performing MAT or maintaining cultures are rarely available, serological test like ELISA could well depict the scenario of the disease prevalence

A retrospective analysis of COVID-19 infection among healthcare workers of south east Assam, India

Background: Health care workers (HCWs) are the frontline warriors, more prone to contracting coronavirus disease 2019 (COVID-19). They also have tremendous possibility of serving as transmission vectors to others. In India there is paucity of data on COVID-19 infection among HCWs. Therefore, it is important to evaluate the infection risk, clinical features, and source of infection, transmission and outcome in HCWs to safeguard them and to check further community spread.Methods: The aim of the study was to investigate the presence of COVID-19 infection among HCWs and to understand the risk factors for infection. Demographic and clinical data of HCWs declared SARS-COV-2 real time RT-PCR positive by VRDL, SMCH, Silchar during June 2020 to July 2021 was obtained from ICMR portal.Results: On data analysis it was found that during the study period a rate of 3.95% (316 out of 7997 cases) infection was among HCWs. Their mean age was 36 years. With maximum cases among male staffs (57.9%), and most common age group was young generation of 17-29 years. The peak acquisition of infection was in July 2020 during ATSP surveillance with 45.5% of infected HCWs. Of the infected HCWs majority were asymptomatic (74%) Although hospitalization rate was high i.e. 82.9% but severity was low with no mortality. Co-morbidity among infected cases was low 23.4%, usually in the aged group of ≥45 years. Doctors/PGTs and Nurses were the highly affected group.Conclusions: Safeguarding the HCWs from infection is the critical need for empowering the healthcare system and overcoming any pandemic in future as well. 

Prognostic Stratification of GBMs Using Combinatorial Assessment of IDH1 Mutation, MGMT Promoter Methylation, and TERT Mutation Status: Experience from a Tertiary Care Center in India

AbstractThis study aims to establish the best and simplified panel of molecular markers for prognostic stratification of glioblastomas (GBMs). One hundred fourteen cases of GBMs were studied for IDH1, TP53, and TERT mutation by Sanger sequencing; EGFR and PDGFRA amplification by fluorescence in situ hybridization; NF1expression by quantitative real time polymerase chain reaction (qRT-PCR); and MGMT promoter methylation by methylation-specific PCR. IDH1 mutant cases had significantly longer progression-free survival (PFS) and overall survival (OS) as compared to IDH1 wild-type cases. Combinatorial assessment of MGMT and TERT emerged as independent prognostic markers, especially in the IDH1 wild-type GBMs. Thus, within the IDH1 wild-type group, cases with only MGMT methylation (group 1) had the best outcome (median PFS: 83.3 weeks; OS: not reached), whereas GBMs with only TERT mutation (group 3) had the worst outcome (PFS: 19.7 weeks; OS: 32.8 weeks). Cases with both or none of these alterations (group 2) had intermediate prognosis (PFS: 47.6 weeks; OS: 89.2 weeks). Majority of the IDH1 mutant GBMs belonged to group 1 (75%), whereas only 18.7% and 6.2% showed group 2 and 3 signatures, respectively. Interestingly, none of the other genetic alterations were significantly associated with survival in IDH1 mutant or wild-type GBMs.Based on above findings, we recommend assessment of three markers, viz., IDH1, MGMT, and TERT, for GBM prognostication in routine practice. We show for the first time that IDH1 wild-type GBMs which constitute majority of the GBMs can be effectively stratified into three distinct prognostic subgroups based on MGMT and TERT status, irrespective of other genetic alterations

A Systematic Review and Meta-analysis of the Impact of Radiation-Related Lymphopenia on Outcomes in High-Grade Gliomas

Introduction  Malignant gliomas are the most common primary malignant brain tumors and are typically treated with maximal safe surgical resection followed by chemoradiation. One of the unintended effects of radiation is depletion of circulating lymphocyte pool, which has been correlated with inferior overall survival outcomes. Methods  A comprehensive and systematic searches of the PubMed, Cochrane Central, and Embase databases were done to assess the studies that have reported radiation-related lymphopenia in high-grade gliomas. Hazard ratios (HRs), odds ratios (OR), and mean differences were represented with Forest plots comparing patients with severe lymphopenia and no severe lymphopenia. Review Manager Version 5.3 (The Nordic Cochrane Centre, Copenhagen, Denmark) was used for the analysis. Results  Nineteen studies were included in the final systematic review and 12 studies were included in the meta-analysis. The odds of developing severe lymphopenia were 0.39 (95% CI:0.19, 0.81, I 2  = 94%, p  = 0.01). Patients with severe lymphopenia were at increased risk of death with a pooled HR = 2.19 (95% CI: 1.70, 2.83, I 2  = 0%, p \u3c0.00001) compared to patients with no severe lymphopenia. The mean difference in survival between patients with severe lymphopenia and no severe lymphopenia was −6.72 months (95% CI: −8.95, −4.49, I 2  = 99%, p \u3c0.00001), with a better mean survival in the no severe lymphopenia group. Conclusion  Radiation-induced severe lymphopenia was associated with poor overall survival and increased risk of death. Photon therapy, larger planning target volume, higher brain dose, higher hypothalamus dose, and female gender were associated with increased risk of severe lymphopenia