Faculty Publications
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Publications by NITK Faculty
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Item Enhanced production of napthoquinone metabolite (shikonin) from cell suspension culture of Arnebia sp. and its up-scaling through bioreactor(Springer Verlag, 2014) Gupta, K.; Garg, S.; Singh, J.; Kumar, M.Cell culture in shake flask and air-lift bioreactor was carried out to exploit the potential of Arnebia sp. for napthoquinone metabolite production. Cell suspension cultures of Arnebia were established from friable callus in liquid MS medium supplemented with 6-benzylaminopurine (BAP) (10 ?M) and indole-3-butyric acid (IBA) (5 ?M). Growth kinetic studies were done by using settled cell volume and fresh/dry cell weight method. Suspension cultures were maintained by sub-culturing at 10 days interval. A two-stage culture system is employed using growth medium (GM) and modified M9 medium (production medium) for cell biomass and naphthoquinone pigment production, respectively. Results showed that cultivation of cells under dark conditions at room temperature (25 ± 2 °C) enhanced the cell biomass from 100 to 625 g l-1. The pigment production was also found to be increased in dark conditions at room temperature. Alkaline pH found to have positive effect on pigment yield. In case of M9 medium constituents, absence of Na2SO4 does not affect the pigment yield. The current approaches have the cumulative effect to meet an increased level of (25.5 ?g/ml) metabolite production in air-lift bioreactor. © 2013 The Author(s).Item Two Automated Techniques for Carotid Lumen Diameter Measurement: Regional versus Boundary Approaches(Springer New York LLC barbara.b.bertram@gsk.com, 2016) Araki, T.; Kumar, P.K.; Suri, H.S.; Ikeda, N.; Gupta, A.; Saba, L.; Rajan, J.; Lavra, F.; Sharma, A.M.; Shafique, S.; Nicolaïdes, A.; Laird, J.R.; Suri, J.S.The degree of stenosis in the carotid artery can be predicted using automated carotid lumen diameter (LD) measured from B-mode ultrasound images. Systolic velocity-based methods for measurement of LD are subjective. With the advancement of high resolution imaging, image-based methods have started to emerge. However, they require robust image analysis for accurate LD measurement. This paper presents two different algorithms for automated segmentation of the lumen borders in carotid ultrasound images. Both algorithms are modeled as a two stage process. Stage one consists of a global-based model using scale-space framework for the extraction of the region of interest. This stage is common to both algorithms. Stage two is modeled using a local-based strategy that extracts the lumen interfaces. At this stage, the algorithm-1 is modeled as a region-based strategy using a classification framework, whereas the algorithm-2 is modeled as a boundary-based approach that uses the level set framework. Two sets of databases (DB), Japan DB (JDB) (202 patients, 404 images) and Hong Kong DB (HKDB) (50 patients, 300 images) were used in this study. Two trained neuroradiologists performed manual LD tracings. The mean automated LD measured was 6.35 ± 0.95 mm for JDB and 6.20 ± 1.35 mm for HKDB. The precision-of-merit was: 97.4 % and 98.0 % w.r.t to two manual tracings for JDB and 99.7 % and 97.9 % w.r.t to two manual tracings for HKDB. Statistical tests such as ANOVA, Chi-Squared, T-test, and Mann-Whitney test were conducted to show the stability and reliability of the automated techniques. © 2016, Springer Science+Business Media New York.Item Influence of knowledge-based safety culture in the construction industry: a stakeholder's perspective(Emerald Group Holdings Ltd., 2021) Deepak, D.; Mahesh, G.Purpose: Safety in construction projects is essential and requires more attention towards minimizing the accident rate. Problems concerning awareness of safety risks, procedures and practices still exist in the industry, which indicate a shortfall in diffusion of safety-related knowledge in construction industry. Also, there is dearth of studies on knowledge management strategies to prevent reoccurrence of accidents and thereby improve safety culture in construction industry. This study attempts to unveil aspects of knowledge management that are ignored in considering safety culture and discern the differences in the perception of key stakeholders of construction industry. Therefore, the objective of this study is to identify and measure knowledge-based safety culture elements. Design/methodology/approach: In this paper, the focus is on the application of a reliable, valid and sensitive knowledge-based safety culture assessment tool on key stakeholders operational in construction industry. Research method adopted is a questionnaire-based survey to seek responses from industry professionals. A total of 199 responses were obtained from 106 different companies operational in Indian construction industry. Statistical analyses including ranking analysis, t-test, correlation analysis, and ANOVA test are utilized for comparing and identifying the differences in view of stakeholder's perceptions concerning workplace safety. Findings: This study helps to identify and rank critical knowledge-based safety culture elements from the perspective of key stakeholders of construction industry. This contributes in identifying the most critical and neglected variables among the key stakeholders regarding aspects of safety culture. Also, the study shows the importance of knowledge dimension in developing overall safety culture in construction industry. Originality/value: Results of this study offer valuable insight in enabling key stakeholders of construction industry to examine and enhance their safety performance. The implications of this study contribute new knowledge in assessing conditions that will improve worker safety in the construction industry. The paper should be of interest to researchers and practitioners in the area of occupational health and safety management. © 2020, Emerald Publishing Limited.Item Duration of dry and humidified incubation of single-step embryo culture medium and oxygen tension during sham culture do not alter medium composition.(F1000 Research Ltd, 2022) Adiga, S.K.; Cheredath, A.; Uppangala, S.; Asampille, G.; Lakshmi, V.; Joseph, D.; Raval, K.; Gowda, N.; Kalthur, G.Background: The extended embryo culture using single-step medium gained popularity in clinical in vitro fertilisation (IVF). However, there are concerns about the degradation of unstable medium components and their negative effects on the developing embryos. Further, dry-incubation can increase osmolality, which can in-turn enhance the concentration of constituents of the media and their stability. Hence, this study was conducted to understand the immediate changes in the culture media constituents in relation to clinically comparable situations such as single-step extended embryo culture and use of dry and humidified-incubation in two-different gaseous conditions. Methods: Commercially available single-step medium was sham-cultured in droplets under oil in two different conditions viz. dry (37°C; 6%CO 2; 5%O 2) and humidified (37°C; 6% CO 2; atmospheric O 2) for 0h, 72h, and 120h intervals. Droplets were subjected to the sensitivity-enhanced nuclear magnetic resonance (NMR)-based profiling using 800 MHz NMR equipped with a cryogenically cooled micro-coil (1.7mm) probe. NMR profile of the embryo culture medium between the two groups were comprehensively assessed. Results: A total of ten amino acids and four energy substrates were identified from the culture medium. The medium constituents identified showed a non-significant increase in the dry-incubation group at 72h and then declined at 120h. Humidified incubation had no effects on the level of the identified medium constituents until 120h. No significant differences in the levels of medium constituents identified were observed between the dry and humidified-groups at various time-points tested. Conclusions: A non-significant variation in the levels of medium constituents observed in the dry-incubation of single-step medium most unlikely to influence a clinical outcome. However, the impact of these subtle changes on the (epi)genetic integrity of the embryos in a clinical set-up to be addressed. © 2022 Cheredath A et al.Item Sustainable replacement of EDTA–Biojarosite for commercial iron in the Fenton’s and UV–Fenton’s degradation of Rhowedamine B – a process optimization using Box–Behnken method(IWA Publishing, 2022) Bhaskar, S.; Rashmishree, K.N.; Manu, B.; Sreenivasa, M.Y.Biojarosite as a replacement for commercial iron catalyst in the oxidative degradation of the dye Rhodamine B was confirmed and established. Investigations on the oxidative degradation by Fenton’s oxidation and UV–Fenton’s oxidation with EDTA at neutral pH were conducted and degradation of target compound was evaluated. UV–Fenton’s oxidation was shown to be efficient over Fenton’s oxidation in the degradation of Rhodamine B with removal efficiency of 90.0%. Design of Experiments was performed with Box–Behnken design. Investigation was conducted for the predicted values separately for both Fenton’s oxidation and UV–Fenton’s oxidation and the Rhodamine B removal was taken as response. Variable parameters biojarosite, H2O2 dosage and EDTA were optimized in the range of 0.1–1 g/L, 2.94–29.4 mM and 10–100 mM, respectively. A quadratic regression model is fitted for both Fenton’s and UV–Fenton’s oxidation. Analysis of variance (ANOVA) is performed and model fit is discussed. © 2022 The Authors.Item Marine chitinase AfChi: green defense management against Colletotrichum gloeosporioides and anthracnose(Springer Science and Business Media Deutschland GmbH, 2024) Rajesh, R.; Raval, K.; Raval, R.Anthracnose disease, caused by the Colletotrichum gloeosporioides species, affects vegetables, fruits, pulses, and cereals, leading to significant economic losses worldwide. Although many synthetic fungicides are used to control this pathogen, eco-friendly biological alternatives are gaining popularity. This study focuses on isolating and purifying chitinase (Af Chi)from a marine bacterium and testing its antifungal efficacy against C. gloeosporioides spore germination by targeting the chitin in the fungal cell wall. The chitinase was purified from a marine bacterium A. faecalis from the Arabian Sea and had a molecular mass of 45 kDa and a specific activity of 84.6 U/mg. Af Chi worked best at 50 °C and pH 7.0 in Tris HCl buffer. Na+ ion was the highest cofactor, highlighting the halophilic nature of this chitinase. K+, Ca2+, Cu2+, Mg2+, Mn2+, and EDTA also increased activity, while Fe3+, Zn2+, Co2+, and Pb2+ decreased it. The Km and Vmax values were 1.87 µg/mL and 17.45 U/mL, respectively. Purified Af Chi at 10 mg/mL completely inhibited spore germination within 8 h and reduced the size of the spores. © The Author(s) 2024.Item Utilization of rice husk and de-oiled cashew nut shell cake agro-wastes to produce ISO standard pellets and its synergistic behavior(Elsevier Ltd, 2025) Suriyakumar, S.; Mahalingam, H.; Ruben Sudhakar, R.S.The biomass pellet market is experiencing rapid growth, playing a critical role in addressing the escalating energy demand and environmental challenges. In India, pellets are predominantly produced from agricultural residues like rice husk, sawdust, straw, corn stalk, sugarcane bagasse, and groundnut shells. Among these, rice husk (RH) pellets are limited by their high ash content, low calorific value, and high moisture requirements during the pelletization process. These limitations can be effectively mitigated through rice husk co-pelletization with deoiled cashew nut shell cake (CC) that remains unexplored in the literature. This study aims to develop rice husk–cashew nut shell (RH-CC) blend pellets by identifying the optimal blend ratio and pelletizing parameters based on their physical and mechanical properties. RH-CC pellets showed that increasing CC addition to RH improved the bulk density, durability and calorific value. The optimization was performed using the desirability functional approach, based on ISO standards. The optimized conditions for 6, 8 and 10 mm pellets were identified as 84, 88, and 81 °C respectively, at a pressure of 180 MPa and 57 % CC blend for which the results are bulk densities of 684, 693, and 652 kg/m3 respectively, pellet durability of 97.1 %, moisture content ranging from 5.4 to 6.3 wt%, and calorific value of 16.7 MJ/kg belonging to I2 category. Additionally, TGA studies were performed to investigate the synergy of the pellets. Utilizing untreated rice husk in RH-CC pellets provides a sustainable alternative to fossil fuels, helping to reduce stubble burning and offering farmers additional income while supporting a cleaner energy future. © 2025 Elsevier Ltd