Browsing by Author "Ashok Kumar Patel"

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Assessing customers' attitude towards online apparel shopping: A three-way interaction model
(Elsevier Inc., 2023) Ashok Kumar Patel; Anurag Singh; Nripendra P. Rana; Satyanarayana Parayitam; Yogesh K. Dwivedi; Vincent Dutot
This paper aims to explore the attitude-intention-purchase behavior mechanism for the online purchase of apparel. Using the theory of planned behavior (TPB) as an underpinning theory, the moderating effects of electronic word of mouth (EWOM), perceived risk, and perceived behavioral control in the relationships have been examined. Data were collected from 432 online apparel consumers using a survey questionnaire. First, the instrument's psychometric properties were checked, and then data was analyzed using Hayes's PROCESS macros. The results indicate that online purchase intention mediates the relationship between consumers' attitudes toward online shopping and actual purchase behavior. In addition, the results found strong support for the three-way interactions between attitude, perceived risk, and EWOM on purchase intention, and (ii) attitude, EWOM, and perceived behavioral control on actual purchase behavior mediated through purchase intention. The three-way interactions involving the double-moderation of EWOM make significant contributions to the growing literature on online buying. © 2023 Elsevier Inc.
Biochemical and spectroscopic characterization of morning glory peroxidase from an invasive and hallucinogenic plant weed Ipomoea carnea
(2008) Ashok Kumar Patel; V.K. Singh; A.J. Moir; Medicherla V. Jagannadham
A novel heme peroxidase MGP from the latex of Ipomoea carnea subsp. fistulosa (morning glory) belonging to the Convolvulaceae family was purified to homogeneity using ammonium sulfate precipitation, anion exchange, hydrophobic interaction, and gel filtration chromatography. The enzyme is glycosylated and has a molecular mass of 42.06 kDa (MALDI-TOF) and an isoelectric point of pH 4.3. The enzyme has high yield, broad substrate specificity, and a high stability toward pH, temperature, chaotrophs, and organic solvents. The extinction coefficient (ε2801% of the enzyme was estimated as 20.56 and it consists of 13 tryptophan, 9 tyrosine, and 8 cysteine residues forming 4 disulfide bridges. There is significant effect of inhibitors targeting S-S bridges (mercaptoethanol, L-cysteine, glutathione), as well as of inhibitors targeting heme (sodium azide and hydroxylamine) on peroxidase activity, whereas inhibition was not observed with ethylmaleinimide due to the absence of reduced cysteine in the enzyme. Polyclonal antibodies against the enzyme have been raised in rabbit, and immunodiffusion suggests that the antigenic determinants of MGP are unique. The N-terminal sequence of MGP (D-E-A-C-I-F-S-A-V-K-E-V-V-D-A) exhibited considerable similarity to the sequence of other known plant peroxidases. Spectroscopic studies (absorbance, fluorescence, and circular dichroism) reveal that MGP has secondary structural features with α/β type with approximately 20% α-helicity. © 2008 American Chemical Society.
Brand equity determinants and ecologically conscious consumer behavior in ridesharing: serial mediation and moderation analysis
(Emerald Publishing, 2024) Anurag Singh; Ashok Kumar Patel; Shefali Jaiswal; Punita Duhan; Vinod Kumar Singh
Purpose: This study focuses on Aaker's Brand Equity Model, to check the effect of brand equity determinants on booking intention (BI) for ridesharing in India. The study also explores the moderation of ecologically conscious consumer behavior (ECCB) on the multiplicative effect of brand awareness (BAw), brand association (BA) and perceived quality (PQ) in influencing the BI. Design/methodology/approach: Responses from 393 Indian ridesharing users were collected using judgmental sampling and were analyzed using Hayes Process macro. Findings: The study found a direct relationship between BAw and BI, BAw and BA, BAw and PQ, BA and PQ, PQ and BI, and BA and BI. Findings revealed mediation of BA in BAw and BI relationship and PQ in BAw and BI relationship. Results revealed that BA and PQ serially mediate BAw and BI relationship. ECCB moderates PQ and BI relationship but not BAw and BI relationship. Research limitations/implications: Serial mediation and moderated-mediation results draw various theoretical implications for determinants of Aaker's Brand Equity model and ECCB. Practical implications: The research has several implications for managers in view of brand equity determinants and ECCB. The study also contributes to policy implications. Originality/value: Study's novel contributions are mediation, serial mediation between brand equity determinants, and moderation of ECCB between BAw and BI for ridesharing. © 2023, Emerald Publishing Limited.
Carnein, a serine protease from noxious plant weed Ipomoea carnea (Morning glory)
(2007) Ashok Kumar Patel; Vijay Kumar Singh; Medicherla V. Jagannadham
A new serine protease from the latex of Ipomoea carnea spp. fistulosa (Morning glory), belonging to the Convolvulaceae family, was purified to homogeneity by ammonium sulfate fractionation followed by cation exchange chromatography. The enzyme, named carnein, has a molecular mass of 80.24 kDa (matrix-assisted laser desorption/ionization time-of-flight) and an isoelectric point of pH 5.6. The pH and temperature optima for proteolytic activity were 6.5 and 65°C, respectively. The extinction coefficient (ε 2801%) of the enzyme was estimated as 37.12, and the protein molecule consists of 35 tryptophan, 76 tyrosine, and seven cysteine residues. The effect of several inhibitors such as iodoacetic acid, diisopropylfluorophosphate, phenyl-methanesulfonyl fluoride, chymostatin, soybean trypsin inhibitor, HgCl2, 3S-3-(N-{(S)-1-[N-(4- guanidinobutyl)carbamoyl]3-ethylbutyl}carbamoyl)oxirane-2-carboxylic acid, N-ethyl maleimide, ethylene glycol-bis(α-amino ethyl ether)tetraacetic acid, ethyl-enediamminetetraacetic acid, and o-phenonthroline indicates that carnein belongs to the family of serine proteases. The enzyme is not prone to autolysis even at very low concentrations. The N-terminal sequence of carnein (T-T-H-S-P-E-F-L-G-L-A-E-S-S-G-L-X-P-N-S) exhibited considerable similarity to those of other plant serine proteases; the highest similarity was with alnus AG12, one of the subtilase family endopepetidases. © 2007 American Chemical Society.
Crystallization and preliminary X-ray analysis of carnein, a serine protease from ipomoea carnea
(2009) Ashok Kumar Patel; Niels Van Oosterwijk; Vijay Kumar Singh; Henritte J. Rozeboom; Kor H. Kalk; Roland J. Siezen; Medicherla V. Jagannadham; Bauke W. Dijkstra
Carnein is an 80 kDa subtilisin-like serine protease from the latex of the plant Ipomoea carnea which displays an exceptional resistance to chemical and thermal denaturation. In order to obtain the first crystal structure of a plant subtilisin and to gain insight into the structural determinants underlying its remarkable stability, carnein was isolated from I. carnea latex, purified and crystallized by the hanging-drop vapour-diffusion method. A data set was collected to 2.0 Å resolution in-house from a single crystal at 110 K. The crystals belonged to the trigonal space group P3121 or P3221, with unit-cell parameters a = b = 126.9, c = 84.6 Å, = Β = 90, = 120°. Assuming the presence of one molecule per asymmetric unit, the Matthews coefficient is 2.46 Å3 Da-1, corresponding to a solvent content of 50%. Structure determination of the enzyme is in progress. © 2009 International Union of Crystallography All rights reserved.
ICChI, a glycosylated chitinase from the latex of Ipomoea carnea
(2009) Ashok Kumar Patel; Vijay Kumar Singh; Ravi Prakash Yadav; A.J.G. Moir; Medicherla V. Jagannadham
A multi-functional enzyme ICChI with chitinase/lysozyme/exochitinase activity from the latex of Ipomoea carnea subsp. fistulosa was purified to homogeneity using ammonium sulphate precipitation, hydrophobic interaction and size exclusion chromatography. The enzyme is glycosylated (14-15%), has a molecular mass of 34.94 kDa (MALDI-TOF) and an isoelectric point of pH 5.3. The enzyme is stable in pH range 5.0-9.0, 80 °C and the optimal activity is observed at pH 6.0 and 60 °C. Using p-nitrophenyl-N-acetyl-β-d-glucosaminide, the kinetic parameters Km, Vmax, Kcat and specificity constant of the enzyme were calculated as 0.5 mM, 2.5 × 10-8 mol min-1 μg enzyme-1, 29.0 s-1 and 58.0 mM-1 s-1 respectively. The extinction coefficient was estimated as 20.56 M-1 cm-1. The protein contains eight tryptophan, 20 tyrosine and six cysteine residues forming three disulfide bridges. The polyclonal antibodies raised and immunodiffusion suggests that the antigenic determinants of ICChI are unique. The first fifteen N-terminal residues G-E-I-A-I-Y-W-G-Q-N-G-G-E-G-S exhibited considerable similarity to other known chitinases. Owing to these unique properties the reported enzyme would find applications in agricultural, pharmaceutical, biomedical and biotechnological fields. © 2009 Elsevier Ltd. All rights reserved.
In Silico Analysis of New Potent Anti-hyperglycemic Molecule for Diabetes Type 2 Management
(Springer, 2020) Kritika Singh; Praveen Kumar Tripathi; Vinay Kumar Singh; Ashok Kumar Patel; O.N. Srivastava; S.K. Singh; Arvind M. Kayastha
Abstract: Diabetes mellitus Type 2 happens to be one of the most challenging health concerns in recent times and has spiked an alarming rise taking it into epidemic category. For management of this epidemic, sulphonylureas have been cornerstone in its treatment. The inefficiency and impairment of insulin to function has been compensated by treatment with anti-hyperglycemic agents (glibenclamide). However, this has been linked with cases of hypoglycemia. In order to rectify this, the present study focuses on development of better drug analogue. Sulphonylurea receptor (SUR1) was modeled with reliable efficiency and confirmed for structural validation. The docking results were strongly supported by molecular dynamics data and molecular mechanics-generalized born surface area (MM-GBSA) calculations. Successful docking of predicted sulphonylurea receptor with designed analogue (C24H26ClN3O4S) was illustrated with stronger binding energy (− 8.3 kcal/mol) having seven hydrophobic contacts and two hydrogen bonds (Ile103and Leu116) with the receptor protein. In case of SUR1-glibenclamide complex, a binding energy of − 7.1 kcal/mol was contributed from four hydrophobic contacts and three hydrogen bonds. The predicted molecule when scrutinized for pharmacophore and QSAR properties, like polar surface area, molar refractivity, oral bioavailability, solubility, transport across the gut, resistance to blood brain barrier and intestinal absorption, showed values mostly falling in prescribed range. It also highlighted that the inhibitor is non-toxic and non-carcinogenic property. Therefore, C24H26ClN3O4S can be used as a better and potent drug for treatment of diabetes Type 2 in comparison to glibenclamide. Graphic Abstract: [Figure not available: see fulltext.]. © 2019, Springer Nature B.V.
Indicain, a dimeric serine protease from Morus indica cv. K2
(2008) Vijay Kumar Singh; Ashok Kumar Patel; A.J. Moir; Medicherla V. Jagannadham
A high molecular mass serine protease has been purified to homogeneity from the latex of Morus indica cv. K2 by the combination of techniques of ammonium sulfate precipitation, hydrophobic interaction chromatography, and size-exclusion chromatography. The protein is a dimer with a molecular mass of 134.5 kDa and with two monomeric subunits of 67.2 kDa and 67.3 (MALDI-TOF), held by weak bonds susceptible to disruption on exposure to heat and very low pH. Isoelectric point of the enzyme is pH 4.8. The pH and temperature optima for caseinolytic activity were 8.5 and 80 °C, respectively. The extinction coefficient (ε2801 %) of the enzyme was estimated as 41.24 and the molecular structure consists of 52 tryptophan, 198 tyrosine and 42 cysteine residues. The enzyme activity was inhibited by phenylmethylsulfonylflouride, chymostatin and mercuric chloride indicating the enzyme to be a serine protease. The enzyme is fairly stable and similar to subtilases in its stability toward pH, strong denaturants, temperature, and organic solvents. Polyclonal antibodies specific to enzyme and immunodiffusion studies reveal that the enzyme has unique antigenic determinants. The enzyme has activity towards broad range of substrates comparable to those of subtilisin like proteases. The N-terminal residues of indicain (T-T-N-S-W-D-F-I-G-F-P) exhibited considerable similarity to those of other known plant subtilases, especially with cucumisin, a well-characterized plant subtilase. This is the first report of purification and characterization of a subtilisin like dimeric serine protease from the latex of M. indica cv. K2. Owing to these unique properties the reported enzyme would find applications in food and pharma industry. © 2008 Elsevier Ltd. All rights reserved.
Neriifolin S, a dimeric serine protease from Euphorbia neriifolia Linn.: Purification and biochemical characterisation
(2012) Ravi Prakash Yadav; Ashok Kumar Patel; M.V. Jagannadham
A dimeric serine protease Neriifolin S of molecular mass 94 kDa with milk clotting activity has been purified from the latex of Euphorbia neriifolia by anion exchange and size-exclusion chromatography. It hydrolyses peptidyl substrates l-Ala-pNA with highest affinity (K m of 0.195 mM) and physiological efficiency (K cat/K m of 144.5 mM s). Enzyme belongs to the class of neutral proteases with pI value of 6.8, optimal proteolytic activity displayed at pH 9.5 and temperature 45 °C. Its proteolytic activity is strongly stimulated in the presence of Ca +2 ions and exclusively inhibited by serine protease inhibitors. Enzyme is fairly stable toward chemical denaturants, pH and temperature. The apparent T m, was found to be 65 °C. Thermal inactivation follow first order kinetics with activation energy (Ea), activation enthalpy (ΔH), free energy change (ΔG) and entropy (ΔS) of 27.54 kJ mol -1, 24.89 kJ mol -1, -82.34 kJ mol -1 and 337.20 J mol -1 K -1. © 2011 Elsevier Ltd. All rights reserved.
Purchase intention of luxury fashion brands in post-pandemic era: A double moderation analysis using information acceptance model
(Routledge, 2023) Anurag Singh; Ashok Kumar Patel; Satyanarayana Parayitam
This study explores the factors influencing luxury fashion brands’ information adoption and purchase intention. Using the information acceptance model (IACM), a double-layered conceptual model was developed to investigate the relationship between various dimensions of information from electronic word of mouth (eWOM) customers receive from social media and information adoption and purchase intention. A survey instrument was used to collect data online from 452 social media users who have purchased luxury fashion brands in India. The hypotheses were tested using AMOS software for structural equation modeling and Hayes PROCESS macros. The results indicate that information credibility, information quality, attitude towards information (ATI), information usefulness, and information needs were positive predictors of consumer information adoption. Results also show that information adoption is positively related to purchase intention. Furthermore, this study has found a significant moderating role of perceived risk (PR) in the relationship between information adoption and purchase intention. Contrary to what has been hypothesized, the three-way interaction between information adoption, PR, and information credibility on purchase intention was not supported. This study focused on the information-adoption-purchase intention of luxury fashion brands, particularly in the context of a developing country, India. © 2023 Informa UK Limited, trading as Taylor & Francis Group.
Purchase intention of luxury fashion brands in post-pandemic era: A double moderation analysis using information acceptance model
(Routledge, 2025) Anurag Singh; Ashok Kumar Patel; Satyanarayana Parayitam
This study explores the factors influencing luxury fashion brands’ information adoption and purchase intention. Using the information acceptance model (IACM), a double-layered conceptual model was developed to investigate the relationship between various dimensions of information from electronic word of mouth (eWOM) customers receive from social media and information adoption and purchase intention. A survey instrument was used to collect data online from 452 social media users who have purchased luxury fashion brands in India. The hypotheses were tested using AMOS software for structural equation modeling and Hayes PROCESS macros. The results indicate that information credibility, information quality, attitude towards information (ATI), information usefulness, and information needs were positive predictors of consumer information adoption. Results also show that information adoption is positively related to purchase intention. Furthermore, this study has found a significant moderating role of perceived risk (PR) in the relationship between information adoption and purchase intention. Contrary to what has been hypothesized, the three-way interaction between information adoption, PR, and information credibility on purchase intention was not supported. This study focused on the information-adoption-purchase intention of luxury fashion brands, particularly in the context of a developing country, India. © 2023 Informa UK Limited, trading as Taylor & Francis Group.
Purification and biochemical characterization of a chymotrypsin-like serine protease from Euphorbia neriifolia Linn.
(2011) Ravi Prakash Yadav; Ashok Kumar Patel; M.V. Jagannadham
Neriifolin, a chymotrypsin-like serine protease, has been purified from the latex of Euphorbia neriifolia Linn. by ammonium sulfate precipitation, cation exchange chromatography and gel filtration. The molecular mass of the enzyme is 35.24 kDa, with an isoelectric point of pH 5.7. The enzyme consists of 18 tryptophan, 25 tyrosine and 9 cysteine residues with 4 disulfide bridges. The extinction coefficient (280nm1%) is 38.28. The Km values are 1.39 ± 0.08 mM and 1.94 ± 0.17 mM, with N-succinyl-l-Phe-p-nitroanilide and α-leucine-p-nitroanilide as substrates, respectively. Neriifolin retains proteolytic activity over a wide range of pH and temperature value, with pH optima of 8.5 and an optimal temperature of 55 °C. Inhibition of enzyme activity by chymostatin and amidolytic activity against synthetic substrates specific to chymotrypsin indicates that the enzyme belongs to chymotrypsin-like serine protease class. Polyclonal antibodies specific to neriifolin and immunodiffusion reveal that the enzyme has unique antigenic determinants. The amino terminal sequence of the first 14 residues of neriifolin is D-F-P-P-N-T-H-I-G-I-P-N-G-Y. A high ratio of milk-clotting activity to proteolytic activity as well as stability against variations in pH and temperature, surfactants, oxidizing agents and compatibility with detergent additives make neriifolin an excellent candidate for industrial applications. © 2011 Elsevier Ltd.
Purification and characterization of a new chitinase from latex of Ipomoea carnea
(2010) Ashok Kumar Patel; Vijay Kumar Singh; Ravi Prakash Yadav; Arthur J.G. Moir; Medicherla. V. Jagannadham
A novel enzyme with endochitinase/lysozyme activity was purified to homogeneity from latex of Ipomoea carnea subsp. fistulosa using latex collection, gum removal, ammonium sulphate precipitation, hydrophobic interaction, and anion exchange chromatography. The enzyme was glycosylated (5-6%) and homogeneous on SDS-PAGE; has a molecular mass of 30.06 kDa (MALDI-TOF) and an isoelectric point of pH 4.6. The enzyme exhibited chitinase activity for hydrolysis of glycol chitin and the chitinolytic activity was significantly inhibited by allosamidin and mercuric chloride. The enzyme is stable in the pH range of 4.0-9.5, 80 °C and the optimal activity was observed at pH 5.5 and 50 °C. The enzyme consists of 8 tryptophan, 14 tyrosine, 6 cysteine residues forming three disulfide bridges and the extinction coefficient was estimated as 21.35 M-1 cm-1. The polyclonal antibody was raised in rabbit and immunodiffusion suggests that the antigenic determinants are unique. The first 15 N-terminal residues G-E-I-T-I-Y-W-G-Q-N-G-F-E-G-S exhibited high identity to other known plant chitinases. Owing to the economic purification, high yield, unique and extraordinary features, stability and behavior; the enzyme ICChII can be widely employed in agriculture, industry, environmental protection, and in recycling chitinous waste from arthropod shellfish and for chito-oligosaccharide production. © 2010 Elsevier Ltd. All rights reserved.
Risk-taking and WOM as moderators in the relationship between status consumption, brand image and purchase intention of counterfeit brand shoes
(Emerald Publishing, 2023) Ashok Kumar Patel; Anurag Singh; Satyanarayana Parayitam
Purpose: The study's objective is to examine the consumers' intention to buy counterfeit brand shoes. A conceptual model is developed to test the risk-taking and word-of-mouth (WOM) as a moderator in the relationship between status consumption, brand image, and consumer intention to buy counterfeit shoes. Design/methodology/approach: Based on the theory of reasoned action (TRA) and signaling theory (ST), this research was conducted in the Indian National Capital Region. Using a structured instrument, the data was collected from 240 respondents. After checking the psychometric properties of the survey instrument using the Lisrel package of structural equation modeling, Hayes's PROCESS macros were used for testing the hypotheses. Findings: The findings from the study indicate that (1) status consumption and brand image are positively associated with purchase intention of counterfeit brand shoes, and (2) risk-taking moderates the relationship between (1) status consumption and purchase intention, and (2) brand image and purchase intension, (3) significant three-way interaction between WOM, risk-taking and status consumption on purchase intention, and (4) significant three-way interaction between brand image, WOM, and risk-taking on purchase intention of counterfeit brand shoes. Research limitations/implications: As with any survey research, this study has common method variance as a potential problem. However, through the latent variable method and Harman's single-factor analysis, the common method variance was checked. The study has several implications for managers, e-marketers, and consumers. Practical implications: The study has several implications for marketers selling counterfeit products and managers intending to protect their branded products. Originality/value: A conceptual model showing two-way and three-way interactions between status consumption, risk-taking, and WOM influencing the consumer purchase intention of counterfeit products was discussed. This is the first of its kind in India to explore such relationships. © 2022, Emerald Publishing Limited.
The relationship between functional theory of attitudes and purchase intention of counterfeit luxury sunglasses: A moderated moderated-mediation conditional model
(Routledge, 2022) Anurag Singh; Ashok Kumar Patel; Satyanarayana Parayitam
This study aims to empirically examine the effect of attitudinal functions: social-adjustive, value-expressive, ego-defensive, and product knowledge on consumer purchase intention for non-deceptive counterfeit Ray-Ban sunglasses. Most importantly, instead of direct relationships, we study the complex inter-relationships between these attitudinal functions on consumers’ purchase intention of counterfeit products. The data were collected from 421 respondents from Eastern UP, India, and after checking the measurement properties of the survey instrument Hayes (2018) PROCESS was used to analyze the data. The results from the study indicate that (i) social-adjustive function is positively related to purchase intention, (ii) social adjustive function is positively related to product knowledge function, (iii) value expressive function moderates the relationship between product knowledge function and purchase intention, (iv) ego defensive function (second moderator) moderates the moderated relationship between social adjustive function and value expressive function (first moderator) mediated through product knowledge function. The results did not support the negative relationship between product knowledge and purchase intention of counterfeit Ray-Ban sunglasses. The present study has several implications for (i) the literature on consumers’ behavior concerning counterfeit products, (ii) managers aiming to sell non-deceptive counterfeit products, and (iii) policy-making bodies and agencies concerning counterfeit products. © 2022 Korean Scholars of Marketing Science.