Investigations on magnetic and electrical properties of Zn doped Fe₂O₃ nanoparticles and their correlation with local electronic structures

Kumar, Parmod,Sharma, Vikas,Singh, Jitendra P.,Kumar, Ashish,Chahal, Surjeet,Sachdev, K.,Chae, K.H.,Kumar, Ashok,Asokan, K.,Kanjilal, D. Elsevier 2019 Journal of magnetism and magnetic materials Vol.489 No.-

<P><B>Abstract</B></P> <P>Present work aims at investigating the structural, magnetic and dielectric properties of zinc doped Fe<SUB>2</SUB>O<SUB>3</SUB> nanoparticles (pure, 10%, 20% & 30%) and correlated with their local electronic structures using X-ray absorption near-edge structure (XANES) spectroscopy. X-ray diffraction and Raman measurements infer that doping of Zn cations lead to the formation of secondary phases corresponding to ZnFe<SUB>2</SUB>O<SUB>4</SUB> along with the hematite phase of Fe<SUB>2</SUB>O<SUB>3</SUB>. Magnetic measurements show that magnetization vs magnetic field curve for 10% Zn doping exhibit maximum saturation magnetization (~2.93 × 10<SUP>−3</SUP> emu/g) as well as the coercivity (~956 Oe). The values of these parameters decrease for higher content of Zn. The temperature dependence of dielectric behaviour follows the same trend as that of the lattice parameter and magnetic measurements. The XANES spectra at Fe L- and Fe K-edges indicate partial reduction of Fe<SUP>3+</SUP> ions into Fe<SUP>2+</SUP> upon Zn doping in the Fe<SUB>2</SUB>O<SUB>3</SUB> lattice. However, divalent state is favourable for Zn (i.e. Zn<SUP>2+</SUP>) within the doping range reported in this study.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Zn doped Fe<SUB>2</SUB>O<SUB>3</SUB> nanoparticles. </LI> <LI> Study of magnetic and electrical properties. </LI> <LI> Correlation of magnetic and electrical properties with local electronic structure. </LI> </UL> </P>

Production of Hepatotoxin by the Cyanobacterium Scytonema sp . Strain BT 23

(Kumar),(Ashok),(D . P . Singh),(M . B . Tyagi),(Arvind Kumar),(E . G . Prasuna),(J . K . Thakur) 한국미생물생명공학회 2000 Journal of microbiology and biotechnology Vol.10 No.3

N/A N/A

Immobilization of Xylanase Using a Protein-Inorganic Hybrid System

( Ashok Kumar ),( Sanjay K. S. Patel ),( Bharat Mardan ),( Raviteja Pagolu ),( Rowina Lestari ),( Seong-hoon Jeong ),( Taedoo Kim ),( Jung Rim Haw ),( Sang-yong Kim ),( In-won Kim ),( Jung-kul Lee ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.4

In this study, the immobilization of xylanase using a protein-inorganic hybrid nanoflower system was assessed to improve the enzyme properties. The synthesis of hybrid xylanase nanoflowers was very effective at 4°C for 72 h, using 0.25 mg/ml protein, and efficient immobilization of xylanase was observed, with a maximum encapsulation yield and relative activity of 78.5% and 148%, respectively. Immobilized xylanase showed high residual activity at broad pH and temperature ranges. Using birchwood xylan as a substrate, the V_max and K_m values of xylanase nanoflowers were 1.60 mg/ml and 455 μmol/min/mg protein, compared with 1.42 mg/ml and 300 μmol/min/mg protein, respectively, for the free enzyme. After 5 and 10 cycles of reuse, the xylanase nanoflowers retained 87.5% and 75.8% residual activity, respectively. These results demonstrate that xylanase immobilization using a proteininorganic hybrid nanoflower system is an effective approach for its potential biotechnological applications.

Radioprotective and Antioxidant Activity of Fractionated Extracts of Berries of Hippophae rhamnoides

Rakesh Kumar Sharma,Raman Chawla,Rajesh Arora,Shikha Singh,Ravinder Kumar Sagar,Raj Kumar,Ashok Sharma,Manju L. Gupta,Surender Singh,Jagdish Prasad,Haider A. Khan,Anand Swaroop,A.K. Sinha,A.K. Gupta,R 한국식품영양과학회 2007 Journal of medicinal food Vol.10 No.1

Plants are an abundant source of medicinal compounds, some of which are useful in combating free radical-1002 (flavonoid-poor fraction) of Hippophae rhamnoideswere screened on the basis of their reducing power in the aqueousphase. REC-1001 was selected for further study, since it exhibited 27.38 times higher antioxidant activity than REC-1002.REC-1001 also showed significant (P. .05) membrane protection potential at 50 .g/mL, which was attributed to its abilityto scavenge peroxyl radicals (64.82. 1.25% scavenging within 1,440 min). A significant (P. .05) difference of 67.02% infree radical scavenging activity at 1,000 ng/mL between REC-1001 and vitamin E demonstrated the extract fraction’s worthc-tion. Further, REC-1001 was found to be nontoxic up to 200 mg/kg of body weight. This research suggests that the REC-1001 fraction of H. rhamnoidesextract is a safe and effective antioxidant nutraceutical product.

Weekly cisplatin or gemcitabine concomitant with radiation in the management of locally advanced carcinoma cervix: results from an observational study

Arun K Verma,Ashok Kumar Arya,Milind Kumar,Anuj Kumar,Sweety Gupta,DN Sharma,GK Rath 대한부인종양학회 2009 Journal of Gynecologic Oncology Vol.20 No.4

Objective: The use of non-platinum drugs in concurrent chemoradiation in carcinoma cervix has not been well explored and hence a two arm study was planned to compare the outcome of concomitant cisplatin or gemcitabine in locally advanced carcinoma cervix. Methods: Thirty six patients were evaluated in this study for response rates and complications. These patients were divided into two arms, sixteen patients in the cisplatin arm and twenty patients in the gemcitabine arm. Cisplatin and gemcitabine were given as i.v. infusion at doses of 40 mg/㎡ and 150 mg/㎡ respectively for five weeks concomitant with radiotherapy. All patients had received pelvic radiotherapy to a dose of 50 Gy/25 fraction/5 weeks by four field box technique followed by high-dose-rate brachytherapy (3 sessions, each of 7.5 Gy to point A). Results: Median follow up was of 10.4 months (range, 3 to 36 months) and 10.9 months (range, 2 to 49 months) in the cisplatin and gemcitabine arms, respectively. At first follow up, 68.8% in the cisplatin arm and 70% in the gemcitabine arm had achieved complete response (p=0.93). Similar response rates were noted in different stages in both arms. None of the patients except one developed grade 4 toxicity. Similar toxicity profiles were observed in both arms. Local disease control, distant disease free survival and overall survival was 68.8% vs. 70%, 93.8% vs. 85%, 68.8% vs. 60% in the cisplatin and gemcitabine arms, respectively. Conclusion: Weekly gemcitabine had similar disease control and tolerable toxicity profile with cisplatin. Gemcitabine may be used as an alternative to cisplatin in patients with compromised renal function. Objective: The use of non-platinum drugs in concurrent chemoradiation in carcinoma cervix has not been well explored and hence a two arm study was planned to compare the outcome of concomitant cisplatin or gemcitabine in locally advanced carcinoma cervix. Methods: Thirty six patients were evaluated in this study for response rates and complications. These patients were divided into two arms, sixteen patients in the cisplatin arm and twenty patients in the gemcitabine arm. Cisplatin and gemcitabine were given as i.v. infusion at doses of 40 mg/㎡ and 150 mg/㎡ respectively for five weeks concomitant with radiotherapy. All patients had received pelvic radiotherapy to a dose of 50 Gy/25 fraction/5 weeks by four field box technique followed by high-dose-rate brachytherapy (3 sessions, each of 7.5 Gy to point A). Results: Median follow up was of 10.4 months (range, 3 to 36 months) and 10.9 months (range, 2 to 49 months) in the cisplatin and gemcitabine arms, respectively. At first follow up, 68.8% in the cisplatin arm and 70% in the gemcitabine arm had achieved complete response (p=0.93). Similar response rates were noted in different stages in both arms. None of the patients except one developed grade 4 toxicity. Similar toxicity profiles were observed in both arms. Local disease control, distant disease free survival and overall survival was 68.8% vs. 70%, 93.8% vs. 85%, 68.8% vs. 60% in the cisplatin and gemcitabine arms, respectively. Conclusion: Weekly gemcitabine had similar disease control and tolerable toxicity profile with cisplatin. Gemcitabine may be used as an alternative to cisplatin in patients with compromised renal function.

Low Pull-in-Voltage RF-MEMS Shunt Switch for 5G Millimeter Wave Applications

P. Ashok Kumar,K. Srinivasa Rao,B. Balaji,M. Aditya,N. P. Maity,Reshmi Maity,Santanu Maity,Ameen El Sinawi,Koushik Guha,K. Girija Sravani 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.6

RF MEMS switches have been employed in many commercial and defense applications due to their high potentiality at microwave and millimeter wave frequencies. In this paper, an RF MEMS shunt switch is designed with perforations and without perforations and simulated using iterative meanders for millimeter wave 5G applications. The proposed iterative meander offers a low spring-constant of 0.68 N/m and reduces the pull-in-voltage upto 1.8 V. The proposed perforated switch design is more reliable which operates with less transition time of 11.2 μs with a quality factor of 1.69. The switch possesses high capacitance ratio of 63. During ON condition, the switch shows low insertion loss of − 0.24 dB at 41 GHz and high isolation of − 46.7 dB at 38 GHz. The performance of the switch is analyzed by simulating it using COMSOL Multiphysics 5.2v (FEM tool). The obtained simulation results shows close approximation with the theoretical results and the switch is efficiently used for 5G millimeter wave applications.

Effect of Varying the Energy Density of Protein-adequate Diets on Nutrient Metabolism, Clinical Chemistry, Immune Response and Growth of Muzaffarnagari Lambs

Singh, V.K.,Pattanaik, Ashok Kumar,Goswami, T.K.,Sharma, K. Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.8

Effects of varied dietary energy densities on immune response and performance of Muzzafarnagari lambs were ascertained in a 180-d study. Animals (n = 24), in three groups, were fed diets providing 100% (100E), 80% (80E) or 70% (70E) of their metabolizable energy requirement. Mean nutrient digestibilities varied significantly among treatments. Nitrogen intake was lower (p<0.01) in the 70E. Nitrogen retention, was reduced (p<0.001) in 80E and 70E vs 100E. The average daily gain (p<0.001) was $47.01{\pm}4.23$, $13.54{\pm}1.72$ and $-16.67{\pm}8.24$ g for 100E, 80E and 70E, respectively. Hemoglobin concentration, haematocrit, total and differential leukocyte counts were lower (p<0.001) for 80E and 70E than for 100E with a similar trend (p<0.05) for serum glucose and total protein. Serum cortisol was reduced (p<0.001) with decreased energy availability. Antibody titre to Brucella abortus S19 showed an initial reduction in 80E and 70E vs 100E. Delayed-type hypersensitivity response was lower (p<0.001) in 80E and 70E vs 100E, accompanying a lower (p<0.001) nitric oxide production by the peripheral lymphocytes. It is concluded that the reduced dietary energy density significantly affects the growth performance and immune response of lambs.

Design and Analysis of MEMS Electrospray Thruster Device

K. Srinivasa Rao,Shaik Shoukat Vali,P. Ashok Kumar,K. Girija Sravani 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.2

This paper reports on MEMS based Electrospray Thruster for high output velocities, low volume, and high throughput. The best possible dimensions of thruster is fix after doing more experimental analysis i.e. cone half angle, propellant radius, propellant height, and cone height. The maximum output velocity is uptrain, propellant at > 300 μm and propellant radius is changed from 60 to 150 μm. Tip angle with 46°, operating voltage varied between 2.5 and 3.5 kV. The Electrospray Thruster design on COMSOL Multiphysics tool in laminar fl ow environment. Propellant inside emitter carry ionic liquid, almost EMI-BF4 is used as propellant. Output velocity of Electrospray Thruster is observed varying input voltages 2–3.5 kV, accompanying diff erent parameters like half angle and height of cone, propellant radius and height. Optimized outcome will be produced at cone angle of 46.5° with height 130 μm and con bottom radius 125 μm along with propellant radius 125 μm propellant height of 125 μm. The output velocities of thrusters are order of 10 6 .

hpvPDB: An Online Proteome Reserve for Human Papillomavirus

Kumar, Satish,Jena, Lingaraja,Daf, Sangeeta,Mohod, Kanchan,Goyal, Peyush,Varma, Ashok K. Korea Genome Organization 2013 Genomics & informatics Vol.11 No.4

Human papillomavirus (HPV) infection is the leading cause of cancer mortality among women worldwide. The molecular understanding of HPV proteins has significant connotation for understanding their intrusion in the host and designing novel protein vaccines and anti-viral agents, etc. Genomic, proteomic, structural, and disease-related information on HPV is available on the web; yet, with trivial annotations and more so, it is not well customized for data analysis, host-pathogen interaction, strain-disease association, drug designing, and sequence analysis, etc. We attempted to design an online reserve with comprehensive information on HPV for the end users desiring the same. The Human Papillomavirus Proteome Database (hpvPDB) domiciles proteomic and genomic information on 150 HPV strains sequenced to date. Simultaneous easy expandability and retrieval of the strain-specific data, with a provision for sequence analysis and exploration potential of predicted structures, and easy access for curation and annotation through a range of search options at one platform are a few of its important features. Affluent information in this reserve could be of help for researchers involved in structural virology, cancer research, drug discovery, and vaccine design.

In Silico Docking to Explicate Interface between Plant-Originated Inhibitors and E6 Oncogenic Protein of Highly Threatening Human Papillomavirus 18

Kumar, Satish,Jena, Lingaraja,Sahoo, Maheswata,Kakde, Mrunmayi,Daf, Sangeeta,Varma, Ashok K. Korea Genome Organization 2015 Genomics & informatics Vol.13 No.2

The leading cause of cancer mortality globally amongst the women is due to human papillomavirus (HPV) infection. There is need to explore anti-cancerous drugs against this life-threatening infection. Traditionally, different natural compounds such as withaferin A, artemisinin, ursolic acid, ferulic acid, (-)-epigallocatechin-3-gallate, berberin, resveratrol, jaceosidin, curcumin, gingerol, indol-3-carbinol, and silymarin have been used as hopeful source of cancer treatment. These natural inhibitors have been shown to block HPV infection by different researchers. In the present study, we explored these natural compounds against E6 oncoprotein of high risk HPV18, which is known to inactivate tumor suppressor p53 protein. E6, a high throughput protein model of HPV18, was predicted to anticipate the interaction mechanism of E6 oncoprotein with these natural inhibitors using structure-based drug designing approach. Docking analysis showed the interaction of these natural inhibitors with p53 binding site of E6 protein residues 108-117 (CQKPLNPAEK) and help reinstatement of normal p53 functioning. Further, docking analysis besides helping in silico validations of natural compounds also helped elucidating the molecular mechanism of inhibition of HPV oncoproteins.