Experimental Studies on Thermal Behavior of 6T Cryogen-Free Superconducting Magnet System

The main aim of this thesis is to report very comprehensive studies and analysis that I have carried out on different thermal aspects of a 6T Cryogen-free Superconducting Magnet System (CFMS) which is designed and built at IUAC. One of important parameter for any superconducting magnet is to achieve the desired field homogeneity by choosing proper dimensional parameter. The role dimensional parameters for the 6T NbTi magnet have been studied to achieve 0.07% field homogeneity at 10mm diametrical spherical volume at the magnetic center. The stability of the 6T NbTi magnet is greatly dependent by its operational margin which is determined by the current sharing temperature of the NbTi. The role of the operational load line has been discussed in determining the stability of the 6T NbTi magnet. The current sharing temperature of the 6T magnet has also been estimated. Two stage GM cryocooler is one of the critical components of the CFMS. The refrigeration load curves for both stages of SRDK-415 GM cryocooler have been generated in a cryocooler based test rig. The refrigeration load curves for the 1st stage of the cryocooler have been generated between 25K and 65K with 0-1.5W of load at the 2nd stage of the cryocooler. Similarly, the refrigeration load curves for the 2nd stage have been generated between 2.4K and 4.4K with 0-47.5W load at 1st stage of the cryocooler. The magnetic field profile for 6T solenoid magnet has been generated with the use of finite element magnetostatic simulation software (OPERA/TOSCA). Hybrid current lead is one of the crucial components of the CFMS. Thermal performance of inter-lead joint between hybrid lead and cold heads of the cryocooler plays a significant role in determining the stability of the NbTi magnet in the CFMS. A prototype lead joint has been characterized in the temperature range of 4-40K in a test rig with different interfacial material (Aluminium nitride/ Kapton) to achieve thermally conducting and electrically isolated joint. The extensive FEM analysis has also done using ANSYS for different types of conduction-cooled leads, optimized for 102A. Quenching is one of the important phenomenon for a superconducting magnet. The protection system for a superconducting magnet needs to be designed ingeniously. In this report, extensive FEM analysis has been done, using OPERA-3D/QUENCH for the 6T NbTi magnet. The analysis has shown the hot spot temperature of the 6T NbTi magnet would be 65-80K, if quenched at 102A. It has been compared with the experimental result. A detailed comparative studies have been done between different types of quench situation. Variable temperature inserts (VTI) is one of common feature integrated with each commercial CFMS to vary temperature on the sample space. The experimental studies have been performed on the gas gap heat switch (GGHS) integrated with CFMS. The feasibility of using GGHS as VTI has been studied up to 3T magnetic field

Arformoterol Tartrate: A Review of Pharmacology, Analysis and Clinical Studies

This article is a review of the therapeutic significance of arformoterol tartrate, a new generation 2 adrenergic agonist bronchodilator available in a nebulized form. Arformoterol is well absorbed through the lungs when administered via a standard jet nebulizer and is useful in long-term maintenance therapy of bronchoconstriction in chronic obstructive pulmonary disease (COPD). Much clinical evidence suggest the potentially enhanced efficacy of this drug in the treatment of COPD including chronic bronchitis and emphysema. Various hyphenated analytical methodologies have also been employed for the determination and quantification of arformoterol. This review provides an updated account on the pharmacology, pharmacokinetics, clinical studies, analytical techniques, drug-drug interactions, contraindications, and therapeutic applications of arformoterol tartrate.Keywords: Arformoterol tartrate, Adrenergic agonist, Bronchodilator, COPDTropical Journal of Pharmaceutical Research December 2010; 9 (6): 595-60

A study on relationship of facebook and game addictive behaviour with personality traits among medical students

Background: Use of social networking sites and playing internet games are more common web activities among adolescents. Students are more prone to internet abuse for several reasons- natural affinity towards internet, free and unlimited access, flexible schedules, and freedom from parental interference and psychological immaturity.  The aim was to study on relationship of facebook and game addictive behaviour with personality characteristics among medical students.Methods: This was a cross sectional observational study, carried out on 140 medical students. All the students were taken randomly. Assessment of sociodemographic details was done with the help of semi-structured performa, bergen facebook addiction scale, game addiction scale and big five inventory were used to see facebook and game addictive behavior and personality traits. Statistical analysis used for comparison of dichotomous variables chi-square test. Correlation and Linear regression was applied to see association. Data analysis was done with the help of statistical software SPSS 23. 0.Results: Mean score of facebook addiction scale among medical students was 39.94 (S.D. 13.133) and mean score of Game addiction scale was 11.19 (S.D. 04.966). It was found that agreeableness (β= -0.275, p=0.000) and extraversion (β = -0.368, p = 0.000) displayed significant associations with FB Total. While neuroticism (β=0.277, p=0.001) and agreeableness (β= -0.177, p=0.029) displayed significant associations with game addictive behavior.Conclusions: In our study we conclude that students with high agreeableness, high neuroticism and low extraversion were more related with Facebook and game addictive behavior. Extraversion was the most powerful predictor of Facebook addiction and neuroticism for gaming addiction.

Substrate-bound crystal structures reveal features unique to Mycobacterium tuberculosis N-acetyl-glucosamine 1-phosphate uridyltransferase and a catalytic mechanism for acetyl transfer

N-Acetyl-glucosamine-1-phosphate uridyltransferase (GlmU), a bifunctional enzyme involved in bacterial cell wall synthesis is exclusive to prokaryotes. GlmU, now recognized as a promising target to develop new antibacterial drugs, catalyzes two key reactions: acetyl transfer and uridyl transfer at two independent domains. Hitherto, we identified GlmU from Mycobacterium tuberculosis (GlmUMtb) to be unique in possessing a 30-residue extension at the C terminus. Here, we present the crystal structures of GlmUMtb in complex with substrates/products bound at the acetyltransferase active site. Analysis of these and mutational data, allow us to infer a catalytic mechanism operative in GlmUMtb. In this SN2 reaction, His-374 and Asn-397 act as catalytic residues by enhancing the nucleophilicity of the attacking amino group of glucosamine 1-phosphate. Ser-416 and Trp-460 provide important interactions for substrate binding. A short helix at the C-terminal extension uniquely found in mycobacterial GlmU provides the highly conserved Trp-460 for substrate binding. Importantly, the structures reveal an uncommon mode of acetyl-CoA binding in GlmUMtb; we term this the U conformation, which is distinct from the L conformation seen in the available non-mycobacterial GlmU structures. Residues, likely determining U/L conformation, were identified, and their importance was evaluated. In addition, we identified that the primary site for PknB-mediated phosphorylation is Thr-418, near the acetyltransferase active site. Down-regulation of acetyltransferase activity upon Thr-418 phosphorylation is rationalized by the structures presented here. Overall, this work provides an insight into substrate recognition, catalytic mechanism for acetyl transfer, and features unique to GlmUMtb, which may be exploited for the development of inhibitors specific to GlmU

Depletion of M. tuberculosis GlmU from infected murine lungs effects the clearance of the pathogen

M. tuberculosis N-acetyl-glucosamine-1-phosphate uridyltransferase (GlmUMtb) is a bi-functional enzyme engaged in the synthesis of two metabolic intermediates N-acetylglucosamine-1-phosphate (GlcNAc-1-P) and UDP-GlcNAc, catalyzed by the C- and N-terminal domains respectively. UDP-GlcNAc is a key metabolite essential for the synthesis of peptidoglycan, disaccharide linker, arabinogalactan and mycothiols. While GlmUMtb was predicted to be an essential gene, till date the role of GlmUMtb in modulating the in vitro growth of Mtb or its role in survival of pathogen ex vivo / in vivo have not been deciphered. Here we present the results of a comprehensive study dissecting the role of GlmUMtb in arbitrating the survival of the pathogen both in vitro and in vivo. We find that absence of GlmUMtb leads to extensive perturbation of bacterial morphology and substantial reduction in cell wall thickness under normoxic as well as hypoxic conditions. Complementation studies show that the acetyl- and uridyl- transferase activities of GlmUMtb are independently essential for bacterial survival in vitro and GlmUMtb is also found to be essential for mycobacterial survival in THP-1 cells as well as in guinea pigs. Depletion of GlmUMtb from infected murine lungs, four weeks post infection, led to significant reduction in the bacillary load. The administration of Oxa33, a novel oxazolidine derivative that specifically inhibits GlmUMtb, to infected mice resulted in significant decrease in the bacillary load. Thus our study establishes GlmUMtb as a strong candidate for intervention measures against established tuberculosis infections

Catastrophic Ice-Debris Flow in the Rishiganga River, Chamoli, Uttarakhand (India)

A catastrophic flood occurred on 7 February 2021 around 10:30 AM (local time) in the Rishiganga River, which has been attributed to a rockslide in the upper reach of the Raunthi River. The Resourcesat 2 LISS IV (8 February 2021) and CNES Airbus satellite imagery (9 February 2021) clearly show the location of displaced materials. The solar radiation observed was higher than normal by 10% and 25% on 6 and 7 February 2021, respectively, however, the temperature shows up to 34% changes. These conditions are responsible for the sudden change in instability in glacier blocks causing deadly rock-ice slides that led to the collapse of the hanging glacier as a wedge failure. The displaced materials mixed with ice, snow, and debris caused catastrophic floods downstream within no time that destroyed critical infrastructure and killed human lives. The hydrodynamic modelling (HEC-RAS software) shows mean flow velocity up to 22.4 ± 8.6 m/s with an average depth of 16.3 ± 6.5 m that caused deadly devastation in the source region and along the rivers due to the flow of water in the valley

DEVELOPMENT OF CAUDAL FIN CELL LINE FROM HILL TROUT Barilius bendelisis (HAMILTON, 1807) FOR CYTOTOXICITY AND TRANSFECTION STUDIES

Stanična linija, nazvana BBdF-1, uspostavljena iz repne peraje Barilius bendelisis, presađena je na više od 52 „oblika“(prolaza) a održavala se u medijima L-15 koji sadrže 20% FBS. Porijeklo stanične linije potvrđeno je pomoću pojačanja djelomičnog područja 16S i COI mitohondrijskih genskih sekvenci. Utvrđeno je da je optimalna temperatura za rast stanične linije BBdF-1 28°C. Kariotipizacijom se utvrdio diploidni broj kromosoma kao 50. Stanice su pokazale snažno vezanje za citokeratinski marker i, prema tome, utvrđeno je da sliče epitelu. Jaka zelena fluorescencija primijećena je u stanicama BBdF-1 transficiranim vektorom phrGFP-II-N, što ukazuje da je prikladna za upotrebu u ispitivanjima ekspresije i manipulacije gena. Izvršena je i uspješna procjena citotoksičnosti dvaju teških metala, žive i kroma. Stanična linija može poslužiti kao koristan izvorni materijal za ranu provjeru toksičnosti pesticida/zagađivača i ekspresije gena.A cell line named BBdF-1, established from the caudal fin of hill stream fish Barilius bendelisis, has been subcultured for more than 52 passages and is being maintained in L-15 media containing 20% FBS. Species origin of the cell line was confirmed using amplification of partial region of 16S and COI mitochondrial gene sequences. The optimum temperature for growth of BBdF-1 cell line was found to be 28°C. Karyotyping revealed diploid chromosome number as 50. Cells exhibited strong binding for cytokeratin marker and thus were found to be epithelial-like. Strong green fluorescence was observed in BBdF-1 cells transfected with phrGFP-II-N vector, indicating its suitability for utilization in gene expression and manipulation studies. Successful assessment of cytotoxicity of two heavy metals, viz. mercury and chromium, was performed. The cell line can serve as a useful resource material for early toxicity screening of pesticides/pollutant and gene expression

An overview of and issues with sky radiometer technology and SKYNET

This paper is an overview of the progress in sky radiometer technology and the development of the network called SKYNET. It is found that the technology has produced useful on-site calibration methods, retrieval algorithms, and data analyses from sky radiometer observations of aerosol, cloud, water vapor, and ozone. A formula was proposed for estimating the accuracy of the sky radiometer calibration constant F0 using the improved Langley (IL) method, which was found to be a good approximation to observed monthly mean uncertainty in F0, around 0.5 % to 2.4 % at the Tokyo and Rome sites and smaller values of around 0.3 % to 0.5 % at the mountain sites at Mt. Saraswati and Davos. A new cross IL (XIL) method was also developed to correct an underestimation by the IL method in cases with large aerosol retrieval errors. The root-mean-square difference (RMSD) in aerosol optical thickness (AOT) comparisons with other networks took values of less than 0.02 for λ≥500 nm and a larger value of about 0.03 for shorter wavelengths in city areas and smaller values of less than 0.01 in mountain comparisons. Accuracies of single-scattering albedo (SSA) and size distribution retrievals are affected by the propagation of errors in measurement, calibrations for direct solar and diffuse sky radiation, ground albedo, cloud screening, and the version of the analysis software called the Skyrad pack. SSA values from SKYNET were up to 0.07 larger than those from AERONET, and the major error sources were identified as an underestimation of solid viewing angle (SVA) and cloud contamination. Correction of these known error factors reduced the SSA difference to less than 0.03. Retrievals of other atmospheric constituents by the sky radiometer were also reviewed. Retrieval accuracies were found to be about 0.2 cm for precipitable water vapor amount and 13 DU (Dobson Unit) for column ozone amount. Retrieved cloud optical properties still showed large deviations from validation data, suggesting a need to study the causes of the differences. It is important that these recent studies on improvements presented in the present paper are introduced into the existing operational systems and future systems of the International SKYNET Data Center