Experimental analysis and development of correlations for gas holdup in high pressure slurry co-current bubble columns

Shyam Kumar,Ashok Khanna 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.11

The effect of liquid and gas velocities, solid concentrations, and operating pressure has been studied ex-perimentally in a 15 cm diameter air-water-glass beads bubble column. The superficial gas and liquid velocities variedfrom 1.0 to 40.00 cm/s and 0 to 16.04 cm/s, respectively, while the solid loading varied from 1 to 9%. The gas holdupin the column was reduced sharply as we switched from batch to co-current mode of operation. At low gas velocity,the effect of liquid velocity was insignificant; while at high gas velocity, increasing liquid velocity decreased the gasholdup. Drift flux approach was applied to quantify the combined effect of liquid and gas velocities over gas holdup. For co-current three phase flows, the gas holdup decreased with increase in solid loading for all pressures. But for batchoperations, when solid loading was 5% or more, settling started leading to higher gas holdup. Increasing pressure fromatmospheric conditions increased the gas holdup significantly, flattening asymptotically.

Exploration on reduced graphene oxide/strontium pyro niobate electrode material for electrochemical energy storage applications

Kumar M. Infant Shyam,Kirupavathy S. Shahil,Shalini S. 한국탄소학회 2021 Carbon Letters Vol.31 No.4

Most recently, graphene-related composite-modifed electrode surfaces are been widely employed to improve surface interactions and electron transfer kinetics. Hydrothermally prepared strontium pyro niobate (SPN) and reduced graphene oxide/ strontium pyro niobate (RGOSPN) nanostructures reveal excellent morphology. X-ray difraction analysis of SPN and RGOSPN agree with standard data. Thermogravimetry–diferential scanning calorimetry analyses show that RGOSPN has higher thermal stability than SPN. In addition, from the polarization–electric feld (P–E) loop measurements, the estimated value of remnant polarization (Pr ) and coercive electric feld (Ec) of SPN are 0.039 µC cm−2 and −2.90 kV cm−1 and that of RGOSPN nanocomposite are 0.0139 µC cm−2 and −2.04 kV cm−1. Cyclic voltammetry measurements show that RGOSPN nanocomposite manifests the possibility of electrochemical reversibility beyond long cycles without change in performance. The redox cycle reveal that RGOSPN can be used as part of a composite electrode for hybrid capacitors dynamic conditions. Moreover, the specifc capacitance of SPN and RGOSPN was calculated using galvanostatic charge–discharge (GCD) technique. The observed energy density of 9.1 W h kg−1 in RGOSPN is higher when compared with previous reported values.

Synthesis and Evaluation of Peptidyl α,β-Unsaturated Carbonyl Derivatives as Anti-malarial Calpain Inhibitors

Shyam Kumar Mallik,Hak Sung Kim,Da Yu Li,Minghua Cui,송현옥,박현 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.3

Malarial calpain is a cysteine protease believed to be a central mediator essential for parasitic activities. N-Acetyl-L-leucyl-L-leucyl-L-norleucinal (ALLN), a calpain inhibitor, showed an excellent inhibitory effect on the erythrocytic stages of Plasmodium falciparum. However the aldehyde group of ALLN makes it susceptible to metabolism. Therefore, we designed α,β-unsaturated carbonyl peptides that could serve as electrophiles for cysteine residues in calpain. Among the synthetic analogs based on the structure of ALLN, peptidyl esters 7, 8 and 9 showed the most potent anti-malarial effects, with the same IC50 values of 5.0 μM. Also they showed the high selective toxicity for the malaria versus Hela cell with 40.6, 69.2 and 24.3 fold for 7, 8 and 9, respectively. Dipeptidyl α,β-unsaturated carbonyl derivatives consisting of two amino acids gave better anti-malarial effects than those consisting with one amino acid. The fluctuation in anti-malarial activity with small changes in chemical structure indicates the possibilities of improving synthetic analogs.

Therapeutic potential of traditionally used medicinal plant Andrographis paniculata (Burm. F.) against diabesity: An experimental study in rats

Ajit Kumar Thakur,Shyam Sunder Chatterjee,Vikas Kumar 셀메드 세포교정의약학회 2014 TANG Vol.4 No.1

Metabolic effects of ten daily doses of standardized extract of Andrographis paniculata leaves (AP) rich in andrographolide were evaluated in a rat model of type-2 diabetes and in diet induced obese rats. AP was administered per-orally as suspension in 0.3% carboxymethylcellulose at doses of 50, 100 and 200 mg/kg/day for 10 consecutive days. Blood glucose, insulin and lipid profile of rats were measured by using enzyme kits. In addition, effects of such treatments on anti-oxidant enzymes activity and histopathological changes in various organs of diabetic rats were assessed. AP treatments reversed body weight losses and increased plasma insulin level in diabetic rats. The anti-oxidant enzymes activity became normal and histopathological changes observed in pancreas, liver, kidney and spleen of diabetic animals were less severe in extract treated groups. On the other hand, hyperinsulinemia and increased body weight gains observed in high fat or fructose fed rats were less severe in the extract treated groups. These observations revealed therapeutic potentials of the extract for treatments of diabesity associated metabolic disorders, and suggest that the effects of the extract on insulin homeostasis depend on the metabolic status of animals. Activation of cytoprotective mechanisms could be involved in its mode of action.

Potential of some traditionally used edible plants for prevention and cure of diabesity associated comorbidities

Vikas Kumar,Ajit Kumar Thakur,Suruchi Verma,Vaishali Yadav,Shyam Sunder Chatterjee 셀메드 세포교정의약학회 2015 셀메드 (CellMed) Vol.5 No.2

Medicinal uses of edible and other plants for prevention and cure of obesity and overweight associated metabolic and mental health problems have since long been known to scholars and practitioners of Ayurvedic and other traditionally known system of medicine. Modernized versions of numerous edible plant derived formulations mentioned in ancient Ayurvedic texts are at present some of the most popular, or best selling, herbal remedies in India and numerous other countries suffering from double burden of diseases caused by malnutrition and obesity. Preclinical and clinical information now available on edible plants and their bioactive constituents justify traditionally known medicinal uses of products derived from them for prevention and cure of obesity associated type-2 diabetes, psychopathologies and other health problems. Such information now available on a few edible Ayurvedic plants and their formulations and suggesting that their stress response regulating effects are involved in their broad spectrums of bioactivity profiles are summarized in this communication. Implications of recent physiological and pharmacological observations made with numerous phytochemicals isolated from edible plants for better understanding of traditionally known medicinal uses of herbal remedies are also pointed out.

인도 여성의 지위와 젠더 불평등의 변화

아난드샴꾸마르 ( Shyam Kumar Anand ) 인문사회 21 2023 인문사회 21 Vol.14 No.1

연구 목적: 이 연구는 양성평등을 추구하는 인도 여성들이 직면하고 있는 중대한 장애물을 찾는 것을 목표로 한다. 인도 헌법은 모든 영역에서 남성과 동등한 권리를 인도 여성에게 부여했다. 그러나 인도 사회에는 오늘날에도 여전히 상당한 성별 불균형이 존재한다. 연구 방법: 연구방법은 국제노동기구(ILO) 데이터 중 여성의 노동 참여율이 낮은 국가를 분석하고 여성의 발전을 촉진하는 메커니즘에 대해 논의했다. 연구 내용: 이 논문의 연구내용은 2010년대 이전의 인도 여성들의 실태를 조사하고 그 시기부터 2020년 초반까지 여성 정책, 사회복지를 포함해 주요 영역에서 일어난 변화를 평가한다. 결론 및 제언: 본 연구에 의하면 인도 여성들의 해방과 자립의 걸림돌은 교육 부족이다. 이는 인도 여성들의 조혼과 경제적 의존이라는 문제도 야기한다. 교육 기관을 지금보다 훨씬 더 많이 설립한다면 이 여성들의 고통은 상당히 줄어들 것이다. This study aims to find out significant obstacles faced by Indian women in their quest for gender equality. The Constitution of India has given Indian women equal rights with men in all spheres. However, even today, there is quite a gender imbalance in Indian society. In this study International Labor Organization data for low female participation in the workforce were analyzed and mechanism to promote the advancement of women were discussed. This research examines the status of women in India before the 2010s and evaluates the changes that have occurred in significant areas, including women’s policy and social welfare since then to the early 2020s. According to this research, lack of education is the major obstacle that hinders the empowerment and emancipation of Indian women and often leads to the problem of child marriage and economic dependence. Setting up a greater number of educational centers may alleviate the pain of women to a large extent.

Therapeutic potentials of Brassica juncea: an overview

Vikas Kumar,Ajit Kumar Thakur,Narottam Dev Barothia,Shyam Sunder Chatterjee 셀메드 세포교정의약학회 2011 TANG Vol.1 No.1

Diverse medicinal uses of different types of products obtainable from Brassica juncea have been known for centuries. Most such traditionally known uses of the plant have been centered on its seeds and oils obtainable from them. During more recent decades diverse bio-active molecules and their therapeutically interesting pharmacological properties of its green edible leaves have also been described, and they are now often considered to be effective substitutes for other so called “healthy” Brassica vegetables. However, little concentrated effort has yet been made to obtain a pharmacologically better defined phyto-pharmaceutical from this easily cultivable plant of commercial interest in many underdeveloped and developing countries. The main aim of this overview is to point out some possibilities for designing and developing such products from the plant for combating the rapidly spreading obesity epidemic in the developed countries and some other countries. Efforts to achieve such goals could as well be an economically more feasible, and culturally more acceptable, starting point for better understanding the potential health benefits of other vegetarian foods.

Andrographolides and traditionally used Andrographis paniculata as potential adaptogens: Implications for therapeutic innovation

Ajit Kumar Thakur,Shyam Sunder Chatterjee,Vikas Kumar 셀메드 세포교정의약학회 2014 셀메드 (CellMed) Vol.4 No.3

Andrographis paniculata (Burm. F.) Wall. Ex Nees (Family: Anthaceae) is a traditionally known Ayurvedic medicinal plant. Several well-controlled clinical trials conducted during recent years have consistently reconfirmed that Andrographis paniculata extracts are effective in suppressing cardinal symptoms of diverse inflammatory and infectious diseases. Despite extensive efforts though, many questions concerning bioactive constituents of such extracts and their modes of actions still remain unanswered. Amongst diverse diterpene lactones isolated to date from such extracts, andrographolide is often considered to be the major, representative, or bioactive secondary metabolite of the plant. Therefore, it has attracted considerable attention of several drug discovery laboratories as a lead molecule potentially useful for identifying structurally and functionally novel drug. Critical analysis of available preclinical and clinical information on Andrographis paniculata extracts and pure andrographolide strongly suggest that they are pharmacologically polyvalent and that they possess adaptogenic properties. Aim of this communication is to summarize and critically analyze such data, and to point out some possibilities for more rationally exploiting their adaptogenic properties for discovering novel therapeutic leads, or for obtaining pharmacologically better standardized phyto-pharmaceuticals.

Anxiolytic-like activity of leaf extract of traditionally used Indian-Mustard (Brassica juncea) in diabetic rats

Ajit Kumar Thakur,Shyam Sunder Chatterjee,Vikas Kumar 셀메드 세포교정의약학회 2013 TANG Vol.3 No.1

Brassica juncea is a polyphenols enriched edible plant, with diverse medicinal uses of different parts of which have been mentioned in the Ayurveda. The effects of 10 daily oral doses (100, 200, and 400 mg/kg/day) of a methanolic Brassica juncea leaf extract in rat models of anxiety using nondiabetic and alloxan-diabetic rats were quantified. In all the three behavioural tests used, i.e. elevated plus maze, open field, and social interaction tests, anxiolytic-like activity of the extract was observed in the diabetic animals only. Quantitatively, the efficacy of the highest tested dose of the extract in these tests was always less than those observed after its lower ones. These observations provide further experimental evidences for the conviction that Brassica vegetables could as well be useful for combating diabetes associated mental health problems.

Photo-induced rapid biosynthesis of silver nanoparticle using aqueous extract of Xanthium strumarium and its antibacterial and antileishmanial activity

Vijay Kumar,Ravi Kumar Gundampati,Devendra Kumar Singh,Medicherla V. Jagannadham,Shyam Sundar,Syed Hadi Hasan 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.37 No.-

The current work describes the biosynthesis of stable AgNPs using aqueous extract of Xanthiumstrumarium (AEX) which act as both reducing as well as a stabilizing agent. The biosynthesis wasconfirmed by UV–visible spectroscopy where the presence of SPR band at lmax 436 nm corresponded tothe existence of AgNPs in reaction mixture. The optimum conditions for biosynthesis of AgNPs were30 min of sunlight exposure time, 3.0% (v/v) of AEX inoculum dose and 3.5 mM AgNO3 concentration. The synthesized AgNPs was characterized by HRTEM, SAED, FESEM, EDX, XRD, AFM, and FTIR whichshowed potent antibacterial and antileishmanial activity.