Faculty Publications
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Item A comparative study on the physico-chemical properties of sol-gel electrospun cobalt oxide nanofibres from two different polymeric binders(Royal Society of Chemistry, 2015) George, G.; Anandhan, S.In this study, two different sacrificial polymeric binders, namely poly(2-ethyl-2-oxazoline) (PEtOx) and poly(styrene-co-acrylonitrile) (SAN) along with cobalt acetate tetrahydrate (CATH), as the metal oxide precursor, were used for the fabrication of Co3O4 nanofibres through sol-gel electrospinning. It was observed that the degradation behaviour and physical properties of SAN and PEtOx influenced the structure, morphology and spectral properties of Co3O4 nanofibres, as the properties of the nanofibres obtained from the aforementioned systems were compared with each other. The grain size, shape and the activation energies for grain growth of Co3O4 nanofibres obtained from these two polymeric systems were different. This difference in grain size and shape caused a difference in the optical band gap energies and the magnetic properties of the Co3O4 nanofibres. This study reveals that one can tailor the characteristics of cobalt oxide nanofibres by an appropriate selection of polymeric binders for sol-gel electrospinning. © The Royal Society of Chemistry.Item Tuning characteristics of Co3O4 nanofiber mats developed for electrochemical sensing of glucose and H2O2(Elsevier B.V., 2016) George, G.; Anandhan, S.Nano-crystalline Co3O4 nanofibrous mats were fabricated by calcining the precursor nanofibers obtained by electrospinning of a sol comprising of a unique polymeric binder poly(2-ethyl-2-oxazoline) and cobalt acetate tetrahydrate in water. The influence of the calcination temperature used for the synthesis of the oxide nanofibers from the xerogel fibers on various physico-chemical properties of the former was studied. The Co3O4 nanofibers obtained at 400 °C had the highest electrochemical sensitivity towards glucose and H2O2. Further, the results prove that Co3O4 nanofibers can be used for the detection of glucose and H2O2 concurrently as the response times taken by these moieties are different. Therefore, one can differentiate the concentration of glucose and H2O2 by analyzing the signals obtained after the respective response time and this multiple sensitivity of Co3O4 can be applied in the field of biosensors. © 2016 Elsevier B.V.Item Cocrystals of Ethenzamide: Study of Structural and Physicochemical Properties(American Chemical Society service@acs.org, 2016) Hariprasad, V.M.; Nechipadappu, S.K.; Trivedi, D.R.Pharmaceutical cocrystals of an analgesic drug ethenzamide (ETZ) with various coformers, namely, gallic acid (GA), 2-nitrobenzoic acid (2NB), 3-nitrobenzoic acid (3NB), 2,4-dinitrobenzoic acid (DNB), and 3-toluic acid (3TA) were synthesized by the solvent evaporation method. All the cocrystals were characterized by various analytical techniques, and the crystal structures were determined by the single-crystal X-ray diffraction method (SCXRD). SCXRD analysis revealed that all the synthesized cocrystals were formed through a robust supramolecular acid-amide heterosynthon except the ethenzamide/gallic acid cocrystal, where molecules interacted through O-H···O hydrogen bond involving -OH of gallic acid and oxygen of amide group of the ETZ molecule. The physicochemical properties such as stability, hygroscopicity, and solubility studies of the ETZ-GA cocrystal were evaluated. It was found that the ETZ-GA cocrystal has a higher solubility (2-fold) than that of the pure ETZ drug molecule. Hygroscopic study of the ETZ-GA cocrystal revealed that synthesized cocrystal was non-hygroscopic at ?75% RH conditions. The ETZ-GA cocrystal found to be stable for a time period of four months at ambient temperature. © 2016 American Chemical Society.Item Hydrothermally synthesized reduced graphene oxide and Sn doped manganese dioxide nanocomposites for supercapacitors and dopamine sensors(Elsevier Ltd, 2017) Shanbhag, D.; Bindu, K.; Aarathy, A.R.; Ramesh, R.; Moolayadukkam, M.; Nagaraja, H.S.?-MnO2 nanowires and its nanocomposites (rGO-MnO2 and Sn@rGO-MnO2) were synthesized by a facile hydrothermal technique. Two important electrochemical applications of nanocomposites, viz, electrodes for supercapacitor and sensors for a biomolecule, dopamine are reported. The prepared nanowires have been characterized by XRD, which reveals smaller crystallite size of rGO- MnO2 composites compared to pristine MnO2 and the trend is supported by BET analysis. The wrapping of MnO2 NWs with rGO sheets increases the surface area, as well as, creates more dislocations at the interfaces. The correlation between physicochemical properties leads to an enhancement in the electrochemical performance of the materials. The as-fabricated Sn@rGO-MnO2 supercapacitor electrode reveals superior performance. The specific capacitance of 139.05, 309.7 and 460.9 F/g at a scanning rate of 20 mV/s, in an aqueous Na2SO4 solution (1 M) is obtained for MnO2, rGO-MnO2 and Sn@rGO-MnO2 respectively. Also, the reported nanocomposites show excellent performance towards detection of dopamine. Among ?-MnO2/GCE, rGO-MnO2/GCE and Sn@rGO-MnO2/GCE based sensors for Dopamine detection, rGO-MnO2/GCE sensor exhibits the highest sensitivity of 433.6 ?A/mM and broad linear range, whereas Sn@rGO-MnO2 exhibits lower detection limit of 0.13 ?M. © 2017 Elsevier LtdItem rGO/MnO2 nanowires for ultrasonic-combined Fenton assisted efficient degradation of Reactive Black 5(IWA Publishing 12 Caxton Street London SW1H 0QS, 2017) Ramesh, M.; Rao, M.P.; Rossignol, F.; Nagaraja, H.S.Reduced graphene oxide (rGO) coated manganese dioxide (MnO2) nanowires (NWs) were prepared by the hydrothermal method. Raman spectra confirmed the presence of rGO and the Brunauer-Emmett-Teller surface area of rGO/MnO2 NWs was found to be 59.1 m2g-1. The physico-chemical properties of prepared catalysts for the degradation of Reactive Black 5 (RB5) dye were investigated. 84% of RB5 dye in hydrogen peroxide solution was successfully degraded using rGO/MnO2 NWs, while only 63% was successfully degraded with pristine ?-MnO2 NWs in 60 min owing to the smaller crystallite size and large surface area. Further, the ultrasonic-combined Fenton process significantly enhanced the degradation rate to 95% of RB5 by the catalyst rGO/MnO2 NWs due to synergistic effects. The decomposition products identified using gas chromatography-mass spectrometry revealed a higher production rate of fragments in the ultrasonic-combined Fenton process. Therefore, rGO/MnO2 NWs with the ultrasonic-combined Fenton process is an efficient catalyst for the degradation of RB5, and may be used for environmental protection. © IWA Publishing 2017.Item A Novel Enzymatic Process to Produce Oxalate Depleted Starch From Taro(Wiley-VCH Verlag info@wiley-vch.de, 2018) Kumar, K.; Belur, P.D.A novel process comprising treatment of Taro (Colocasia esculenta (L.) Schott) tuber flour with oxalate oxidase enzyme is developed to deplete the oxalate content. Oxalate oxidase enzyme produced by an endophyte, Ochrobactrum intermedium CL6 is employed to treat taro tuber flour. The treatment followed by extraction of starch results in a 97% reduction in total oxalate content. Further, several physicochemical properties such as paste clarity, swelling power, solubility, amylose content, granule size of starch produced out of enzyme treatment are studied and compared with properties of taro starch produced without enzyme treatment. The study reveals that enzyme treatment does not bring appreciable changes in the studied parameters. The taro starch produced by enzyme treatment shows very low paste clarity (9.38%), high swelling power (15.32 g/g), very low solubility (21.66%), and low amylose content (7.52%) at 100 °C compared to potato and sweet-potato starches. X-ray diffraction data reveal that taro starch possesses an A-crystalline form, unlike the B-crystalline form found in potato and sweet potato starch. To the best of the authors knowledge, for the first time, the use of oxalate oxidase to produce oxalate depleted taro starch is reported. One of the interesting food industry applications of oxalate-depleted taro starch, among many other uses could be for baby food formulation because of its small granule size. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimItem Emulsification of bio-crude produced from agricultural waste via hydrothermal liquefaction process(Elsevier Ltd, 2021) Bhat, S.; Borugadda, V.B.; Dalai, A.K.In the present study, bio-crude obtained from hydrothermal liquefaction of waste wheat flour and canola meal (residue after extraction of canola oil) was emulsified with the light cycle oil (LCO) using octanol as an emulsifier. Emulsification process parameters such as mixing time, temperature, stirring intensity, and emulsifier, bio-crude, LCO concentrations were varied and studied to obtain a final emulsion that could be used as a fuel in diesel engines. Favorable process conditions for the emulsion were found to be 25 min of mixing time at 105 ? temperature with a stirring intensity of 1000 rpm, and emulsifier, bio-crude, and LCO concentrations as 5, 10, and 85 wt% respectively. Various physicochemical properties of the formulated emulsion with bio-crude were studied which showed an improvement compared to the bio-crude used. The physicochemical properties of the emulsion were compared with the blends of conventional diesel fuel that do not contain additives, canola biodiesel for emulsion stability. Comparative analysis of the emulsion physicochemical properties revealed that the emulsion properties are very close to ASTM D 6751-09 biodiesel specifications. © 2021 Elsevier LtdItem An effective feature extraction with deep neural network architecture for protein-secondary-structure prediction(Springer, 2021) Jayasimha, A.; Mudambi, R.; Pavan, P.; Lokaksha, B.M.; Bankapur, S.; Patil, N.With the increased importance of proteins in day-to-day life, it is imperative to know the protein functions. Deciphering protein structure elucidates protein functions. Experimental approaches for protein-structure analysis are expensive and time-consuming, and require high dexterity. Thus, finding a viable computational approach is vital. Due to the high complexity of predicting protein structure (tertiary structure) directly, research in this field aims at the protein-secondary-structure prediction which is directly related to its tertiary structure. This research aims at exploring a plethora of features, namely position-specific scoring matrices, hidden Markov model alignment matrices, and physicochemical properties, that carry rich information required to predict the secondary structure. Furthermore, it aims at exploring a suitable combination of the features which could capture diverse information about the protein secondary structure. Finally, a cascaded convolutional neural network and bidirectional long short-term memory architecture is fit on the models, and two evaluation metrics, namely, Q8 score and segment overlap score, are benchmarked on various datasets. Our proposed model trained on data of CB6133 dataset and tested on CB513 dataset beats the benchmark models by a minimum of 2.9%. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.Item Investigation of structural and physico-chemical properties of rice starch with varied amylose content: A combined microscopy, spectroscopy, and thermal study(Elsevier B.V., 2022) Govindaraju, I.; Zhuo, G.-Y.; Chakraborty, I.; Melanthota, S.K.; Mal, S.; Sarmah, B.; Baruah, V.J.; Mahato, K.K.; Mazumder, N.Starch from a given botanical source can vary considerably in terms of physicochemical properties in its native and hydrolyzed forms. The current study investigated the structural and functional characteristics of starch from ten indigenous rice varieties endemic to Northeast India. In vitro enzymatic hydrolysis was used to reveal the dextrose equivalent profile of each type of starch. Gezep Sali and Betguti Sali respectively exhibited the highest and lowest starch hydrolysis. Among the ten rice varieties, amylose content varied between 7.50 and 28.58%. Optical and scanning electron microscopy (SEM) revealed the polyhedral shape of the native starch granules and deformation of the shape upon enzymatic hydrolysis. Second harmonic generation (SHG) microscopy and X-ray diffraction (XRD) analysis confirmed the presence of and variations in starch crystallinity. XRD revealed spectral peaks characteristic of A-type starch crystals in the native form. The elevated intensity of XRD peaks in hydrolyzed starch granules confirmed the occurrence of amylose hydrolysis rather than hydrolysis in amylopectin regions. Fourier transform infrared (FTIR) spectra revealed the common stretching and bending of bonds in all native starches; however, changes were observed in the fingerprint region (1080, 1000, 926 cm−1) of hydrolyzed starch granules, which indicates the amylolysis of the amylose region and disturbances in the ordered arrangement in the crystalline part. Differential scanning calorimeter (DSC) endotherms revealed the highest and lowest gelatinization peak temperatures in Harfoni (78 °C) and Tulosi Sali (41 °C) rice cultivars, respectively. The findings in this study can help to optimize the usage of rice starch in food and non-food industries. Furthermore, understanding the control points of starch digestion and genetically tailoring rice grains with different digestibility could be beneficial for nutraceutical applications. © 2021 Elsevier LtdItem Investigation of physico-chemical properties of native and gamma irradiated starches(Elsevier Ltd, 2022) Govindaraju, I.; Sunder, M.; Chakraborty, I.; Mumbrekar, K.D.; Mal, S.; Mazumder, N.Starch is one of the most abundantly found carbohydrates in cereals, roots, legumes and fruits located in amyloplasts of plants. Native starch comprises of amylose, a linear α-glucan with α-1,4-linkage and amylopectin, a branched polysaccharide with both α-1,4-linkage and α-1,6-linkage. In food industries, the native starch is modified to manufacture the desired quality of starchy foods by means of physical, chemical, and enzymatic modification techniques. Gamma irradiation technique is one among the physical modifications of starch which is extensively used for the modification of native starch as it is rapid, less toxic and cost-effective technique. When starch is radiated with gamma rays, it is observed to produce free radicals owing to cleavage of amylopectin branches and exhibit variation in their physicochemical properties. In this study, commercially available corn, rice, and potato starch were irradiated with 10 kGy dose of gamma radiation and changes in their physicochemical properties were investigated. Native and irradiated starch was subjected to enzymatic hydrolysis with bacterial α-amylase (150 U/mL). The highest starch hydrolysis was observed for irradiated rice starch (17.03%). Amylose content of irradiated starch decreased by 3–4 %. The optical microscopic images showed the surface erosions of the irradiated starch and differential scanning calorimeter (DSC) revealed the thermal transition temperatures. Overall, starch hydrolysis and amylose content showed inverse correlation between them. Further studies regarding the effect of storage on gamma irradiated starch can help to gain new insights into the usage of modified starches in the manufacture of processed foods. © 2022