59 research outputs found
Isolation, purification, and physio-chemical characterization of melanin pigment from nigerseed hulls (Guizotia abyssinica).
No full textABSTRACT
Plant melanin, a natural pigment, has gained significant attention recently due to its potential
therapeutic and industrial applications. In this study, melanin pigments were extracted from
Nigerseed hulls (NH) via alkali and acid extraction methods, followed by acid hydrolysis, organic
solvent treatment, and repeated precipitation. The solubility of NH melanin was assessed, revealing
solubility in alkali and dimethyl sulfoxide (DMSO) but insolubility in other common organic solvents.
High-performance liquid chromatography (HPLC) was employed to measure the purity of NH
melanin in comparison to standard melanin, while elemental analysis indicated a similarity between
melanin extracted from nigerseed hulls and the standard counterpart. LC-MS data revealed a
molecular weight of NH melanin. Furthermore, the stability of melanin was evaluated under varying
conditions including temperature, oxidants, reducing agents, light exposure, and metal ion presence.
Results demonstrated significant effects of Mg2+, Cu2+, and Fe2+ metal ions on melanin stability, with
a minor effect observed for Ca2+, while sodium hyposulfite was found to destabilize the pigments.
Our findings suggest that nigerseed hulls hold promise as a novel source for efficient melanin
production, with potential applications in the food sector, food packaging, and biomedical fields
Gender disparity in Indian library and information science journals: An analytical study
No full textObjective. This study investigates gender disparity in research productivity in Indian Library and Information Science (LIS) journals, focusing on authorship patterns, professional engagement, prolific institutions, and regional productivity.
Methodology. We analyzed 2404 articles with 4583 authors from ten selected Indian LIS journals (2014–2023). Author details, including gender, institutional affiliation, and authorship roles, were collected from biographical notes and recorded in Excel sheets. The analysis involved descriptive statistics and inferential tests (Chi-square tests and correlation analysis) using SPSS software.
Findings. The study revealed a significant gender disparity in Indian LIS research, with male authors representing 71.81% of contributions and dominating first authorship roles (69.3%). Collaborative authorship patterns were also male-dominated, with male-only and male-majority teams prevailing. Faculty members of the University of Delhi and Aligarh Muslim University emerged as the top contributors. Female representation was more visible among research scholars in the KELPRO journal, which showed a balanced gender representation. Regional analyses showed that contributions from New Delhi, West Bengal, and Karnataka were the highest, with minimal representation from states such as Sikkim and Nagaland.
Conclusions. This study highlights the persistence of gender disparity in Indian LIS scholarship and provides valuable insights into authorship dynamics, institutional productivity, and regional representation. These findings offer actionable recommendations for fostering inclusivity and gender equity in Indian LIS research
A case study of 2019-nCOV cases in Argentina with the real data based on daily cases from March 03, 2020 to March 29, 2021 using classical and fractional derivatives
No full text[EN] In this study, our aim is to explore the dynamics of COVID-19 or 2019-nCOV in Argentina considering the parameter values based on the real data of this virus from March 03, 2020 to March 29, 2021 which is a data range of more than one complete year. We propose a Atangana-Baleanu type fractional-order model and simulate it by using predictor-corrector (P-C) method. First we introduce the biological nature of this virus in theoretical way and then formulate a mathematical model to define its dynamics. We use a well-known effective optimization scheme based on the renowned trust-region-reflective (TRR) method to perform the model calibration. We have plotted the real cases of COVID-19 and compared our integer-order model with the simulated data along with the calculation of basic reproductive number. Concerning fractional-order simulations, first we prove the existence and uniqueness of solution and then write the solution along with the stability of the given P-C method. A number of graphs at various fractional-order values are simulated to predict the future dynamics of the virus in Argentina which is the main contribution of this paper.The third author is supported by MICINN and FEDER, Project PID2019-105011GB-I00.Kumar, P.; Erturk, VS.; Murillo Arcila, M.; Banerjee, R.; Manickam, A. (2021). A case study of 2019-nCOV cases in Argentina with the real data based on daily cases from March 03, 2020 to March 29, 2021 using classical and fractional derivatives. Advances in Difference Equations. 2021(1):1-21. https://doi.org/10.1186/s13662-021-03499-2S12120211Wu, Z., McGoogan, J.M.: Characteristics of and important lessons from the coronavirus disease 2019 (Covid-19) outbreak in China: summary of a report of 72 314 cases from the Chinese center for disease control and prevention. JAMA 323(13), 1239–1242 (2020)Zhang, C., Zheng, W., Huang, X., Bell, E.W., Zhou, X., Zhang, Y.: Protein structure and sequence reanalysis of 2019-ncov genome refutes snakes as its intermediate host and the unique similarity between its spike protein insertions and hiv-1. J. Proteome Res. 19(4), 1351–1360 (2020)Hui, D.S., Azhar, E.I., Madani, T.A., Ntoumi, F., Kock, R., Dar, O., Ippolito, G., Mchugh, T.D., Memish, Z.A., Drosten, C., et al.: The continuing 2019-ncov epidemic threat of novel coronaviruses to global health—the latest 2019 novel coronavirus outbreak in Wuhan, China. Int. J. Infect. Dis. 91, 264–266 (2020)Elfiky, A.A., Mahdy, S.M., Elshemey, W.M.: Quantitative structure-activity relationship and molecular docking revealed a potency of anti-hepatitis C virus drugs against human corona viruses. J. Med. Virol. 89(6), 1040–1047 (2017)Li, X., Zai, J., Zhao, Q., Nie, Q., Li, Y., Foley, B.T., Chaillon, A.: Evolutionary history, potential intermediate animal host, and cross-species analyses of Sars-Cov-2. J. Med. Virol. 92(6), 602–611 (2020)Wrapp, D., Wang, N., Corbett, K.S., Goldsmith, J.A., Hsieh, C.-L., Abiona, O., Graham, B.S., McLellan, J.S.: Cryo-em structure of the 2019-ncov spike in the prefusion conformation. Science 367(6483), 1260–1263 (2020)Villar, J., Zhang, H., Slutsky, A.S.: Lung repair and regeneration in ards: role of pecam1 and wnt signaling. Chest 155(3), 587–594 (2019)Wang, H., Ma, S.: The cytokine storm and factors determining the sequence and severity of organ dysfunction in multiple organ dysfunction syndrome. Am. J. Emerg. Med. 26(6), 711–715 (2008)Wan, Y., Shang, J., Graham, R., Baric, R.S., Li, F.: Receptor recognition by the novel coronavirus from Wuhan: an analysis based on decade-long structural studies of Sars coronavirus. J. Virol. 94(7), e00127-20 (2020)Tang, N.L.-S., Chan, P.K.-S., Wong, C.-K., To, K.-F., Wu, A.K.-L., Sung, Y.-M., Hui, D.S.-C., Sung, J.J.-Y., Lam, C.W.-K.: Early enhanced expression of interferon-inducible protein-10 (cxcl-10) and other chemokines predicts adverse outcome in severe acute respiratory syndrome. Clin. Chem. 51(12), 2333–2340 (2005)Gu, J., Korteweg, C.: Pathology and pathogenesis of severe acute respiratory syndrome. Am. J. Pathol. 170(4), 1136–1147 (2007)Ho, J.C., Chan, K.N., Hu, W.H., Lam, W.K., Zheng, L., Tipoe, G.L., Sun, J., Leung, R., Tsang, K.W.: The effect of aging on nasal mucociliary clearance, beat frequency, and ultrastructure of respiratory cilia. Am. J. Respir. Crit. Care Med. 163(4), 983–988 (2001)Kumar, P., Erturk, V.S., Murillo-Arcila, M.: A new fractional mathematical modelling of Covid-19 with the availability of vaccine. Results Phys. 24, 104213 (2021)Kumar, P., Erturk, V.S.: A case study of Covid-19 epidemic in india via new generalised Caputo type fractional derivatives. Math. Methods Appl. Sci., 1–14 (2021)Kumar, P., Erturk, V.S., Abboubakar, H., Nisar, K.S.: Prediction studies of the epidemic peak of coronavirus disease in Brazil via new generalised Caputo type fractional derivatives. Alex. Eng. J. 60(3), 3189–3204 (2021)Nabi, K.N., Kumar, P., Erturk, V.S.: Projections and fractional dynamics of Covid-19 with optimal control strategies. Chaos Solitons Fractals 145, 110689 (2021)Erturk, V.S., Kumar, P.: Solution of a Covid-19 model via new generalized Caputo-type fractional derivatives. Chaos Solitons Fractals 139, 110280 (2020)Gao, W., Veeresha, P., Baskonus, H.M., Prakasha, D., Kumar, P.: A new study of unreported cases of 2019-ncov epidemic outbreaks. Chaos Solitons Fractals 138, 109929 (2020)Kumar, P., Suat Erturk, V.: The analysis of a time delay fractional Covid-19 model via Caputo type fractional derivative. Math. Methods Appl. Sci., 1–14 (2020)Atangana, A., Araz, S.İ.: Modeling and forecasting the spread of Covid-19 with stochastic and deterministic approaches: Africa and Europe. Adv. Differ. Equ. 2021(1), 1 (2021)Atangana, A.: Modelling the spread of Covid-19 with new fractal-fractional operators: can the lockdown save mankind before vaccination? Chaos Solitons Fractals 136, 109860 (2020)Atangana, A., Araz, S.İ.: Mathematical model of Covid-19 spread in Turkey and South Africa: theory, methods, and applications. Adv. Differ. Equ. 2020(1), 1 (2020)Atangana, A., et al.: A novel Covid-19 model with fractional differential operators with singular and non-singular kernels: analysis and numerical scheme based on Newton polynomial. Alex. Eng. J. 60(4), 3781–3806 (2021)Bulut, H., Kumar, D., Singh, J., Swroop, R., Baskonus, H.M.: Analytic study for a fractional model of hiv infection of cd4+ t lymphocyte cells. Math. Nat. Sci. 2(1), 33–43 (2018)Zhoua, Y.-H., Yang, Y., Zhang, H.: Stability of non-monotone critical waves in a population dynamics model with spatio-temporal delay. Math. Nat. Sci. 2, 8–23 (2018)Musa, S.S., Qureshi, S., Zhao, S., Yusuf, A., Mustapha, U.T., He, D.: Mathematical modeling of Covid-19 epidemic with effect of awareness programs. Infect. Dis. Model. 6, 448–460 (2021)Memon, Z., Qureshi, S., Memon, B.R.: Assessing the role of quarantine and isolation as control strategies for Covid-19 outbreak: a case study. Chaos Solitons Fractals 144, 110655 (2021)Kumar, P., Suat Ertürk, V., Nisar, K.S.: Fractional dynamics of huanglongbing transmission within a citrus tree. Math. Methods Appl. Sci. (2021)Kumar, P., Erturk, V.S., Murillo-Arcila, M.: A complex fractional mathematical modeling for the love story of layla and majnun. Chaos Solitons Fractals 150, 111091 (2021)Kumar, P., Erturk, V.S., Yusuf, A., Kumar, S.: Fractional time-delay mathematical modeling of oncolytic virotherapy. Chaos Solitons Fractals 150, 111123 (2021)Abboubakar, H., Kumar, P., Erturk, V.S., Kumar, A.: A mathematical study of a tuberculosis model with fractional derivatives. Int. J. Model. Simul. Sci. Comput. (2021)Kumar, P., Rangaig, N.A., Abboubakar, H., Kumar, S.: A malaria model with Caputo–Fabrizio and Atangana–Baleanu derivatives. Int. J. Model. Simul. Sci. Comput. 12(2), 2150013 (2020)Kumar, P., Erturk, V.S., Yusuf, A., Nisar, K.S., Abdelwahab, S.F.: A study on canine distemper virus (cdv) and rabies epidemics in the red fox population via fractional derivatives. Results Phys. 25, 104281 (2021)Kumar, P., Erturk, V.S., Almusawa, H.: Mathematical structure of mosaic disease using microbial biostimulants via Caputo and Atangana–Baleanu derivatives. Results Phys. 24, 104186 (2021)Kumar, P., Erturk, V.S.: Environmental persistence influences infection dynamics for a butterfly pathogen via new generalised Caputo type fractional derivative. Chaos Solitons Fractals 144, 110672 (2021)Nabi, K.N., Abboubakar, H., Kumar, P.: Forecasting of Covid-19 pandemic: from integer derivatives to fractional derivatives. Chaos Solitons Fractals 141, 110283 (2020)Van den Driessche, P., Watmough, J.: Reproduction numbers and sub-threshold endemic equilibria for compartmental models of disease transmission. Math. Biosci. 180(1–2), 29–48 (2002)Nabi, K.N.: Forecasting Covid-19 pandemic: a data-driven analysis. Chaos Solitons Fractals 139, 110046 (2020)Politologue.com: Coronavirus (Covid19), https://coronavirus.politologue.com/coronavirus-cameroun.CM. 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Characterization, antioxidant, and antimicrobial activity of melanin extracted from nigerseed hulls
No full textThis study aims to characterize and explore the biological effects of melanin derived from nigerseed (Guizotia
abyssinica) hulls, which are inedible. Extracted melanin was selectively soluble in alkali and DMSO. The melanin
extract demonstrated robust antioxidant and DPPH radical scavenging activities. It exhibited strong antibacterial
effects against foodborne pathogens, as indicated by the zone of inhibition (in mm); Salmonella enterica (40.00 ±
0.00), Staphylococcus aureus (37.33 ± 1.15), Micrococcus luteus (31.67 ± 0.58), Klebsiella oxytoca (31.33 ± 1.15),
Escherichia coli (30.33 ± 0.58), and Bacillus cereus (28.33 ± 1.15). For antifungal activity, melanin displayed
selectivity, suggesting its potential as a targeted antifungal agent. This research highlights nigerseed byproducts
as a cost-effective and promising source for melanin production, showcasing its potential in the pharmaceutical
sector as a natural alternative to chemically derived drugs
ANALYZING CUSTOMER VALUE USING CONJOINT ANALYSIS: THE EXAMPLE OF A PACKAGING COMPANY
No full textThe fulfillment of customers’ wishes in a profitable way requires that companies understand which aspects of their product and service are most valued by the customer. Conjoint analysis is considered to be one of the best methods for achieving this purpose. Conjoint analysis consists of generating and conducting specific experiments among customers with the purpose of modeling their purchasing decision. This article will give an overview of the method and apply it to an Estonian packaging company. As a result of the empirical study the author is able to estimate the value creation models of 34 respondents (customers) both on a group and individual basis.customer value, conjoint analysis, market research methods
Measuring the effect of customer relationship management (CRM) components on the non financial performance of commercial banks: Egypt case
No full textThis paper presents customer relationship management (CRM) components as applied on the Egyptian Commercial Banks, examined from the bankers' point of view. Then, it intends to measure their effect on the level of customer satisfaction and loyalty from the customers’ point of view as examples of the non financial performance measures. The paper is quantitative in nature and consists of two different structured questionnaires using convenience/quota sampling. The first involved 180 employees in order to measure CRM applicability, and the second involved 270 customers to measure the level of customer satisfaction and loyalty and their effect on the Egyptian Commercial Banks' financial performance The findings show that the selected banks apply CRM components but the level of application differs from one bank to another. The results showed a significant positive relationship between CRM and customer satisfaction in the Egyptian Commercial Banks, when applying them together and not separately. In addition, there is a strong positive effect between customer satisfaction and loyalty which was reflected on the Commercial Banks' financial performance. The findings confirm the importance of studying and implementing CRM to achieve customer loyalty and improve the Egyptian Commercial Banks financial performance. Banks wishing to improve their relationships with customers need to focus on the CRM components to develop relevant and effective marketing strategies and tactics. The paper measures the CRM as a multidimensional construct as applied on the Egyptian Commercial Banks and relate it to the achievement of the ultimate goal of retaining customers to gaining a sustainable competitive advantage and achieve more profits
Author Correction: Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017 (Nature Medicine, (2020), 26, 5, (750-759), 10.1038/s41591-020-0807-6)
No full textAn amendment to this paper has been published and can be accessed via a link at the top of the paper. © 2020, The Author(s)
Author Correction: Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017 (Nature Medicine, (2020), 26, 5, (750-759), 10.1038/s41591-020-0807-6)
No full textAn amendment to this paper has been published and can be accessed via a link at the top of the paper. © 2020, The Author(s)
Author Correction: Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017 (Nature Medicine, (2020), 26, 5, (750-759), 10.1038/s41591-020-0807-6)
No full textAn amendment to this paper has been published and can be accessed via a link at the top of the paper. © 2020, The Author(s)
Polymer-based treatments to control runoff, leachate and erosion from engineered slopes at Simfer Mine, Guinea, Africa
No full textIt is necessary to understand the erodibility and hydrological response of mine-site slope forming materials (SFMs), because of increasing awareness of the environmental impacts of mining. Steep engineered slopes in high intensity rainfall environments present a serious erosion risk. Temporary surface stabilisers, such as polyacrylamides (PAMs) and polyvinylacrylic latex (PVALs) are potentially cost effective erosion control solutions. In this study PAM and PVAL efficacy to reduce runoff, leachate and erosion was assessed at two application rates, with and without gypsum on SFMs from an iron ore mine in Guinea (West Africa). NSPASS (near-surface photogrammetry assessment of slope forming materials’ surface roughness) is a novel method that integrates digital image capture and GIS. It is shown to detect and quantify surface micro-relief changes of 2-3 mm, not visible to the naked eye.
As expected, soil and non-soil SFMs were significantly different in terms of their physical and chemical properties. Phase I of the study investigated the erodibility of ten SFMs, including soil, ore and waste-rock. The results indicate that the hydrological response to rainfall of most SFMs is to generate leachate. Weathered phyllite (PHY-WEA) is the most erodible SFM by both runoff and leachate. Multiple regression analysis demonstrated that magnetic susceptibility, mineralogy and dry aggregate distribution; parameters not commonly assessed in erosion studies, are important in explaining SFM erodibility and hydrological response.
Phase II evaluated critically the effectiveness of three commercially available polymer solutions (two PAMs and one PVAL) at reducing runoff, leachate and erosion from four of the most erodible SFMs identified in Phase I. The results indicate that some PAM and PVAL treatments significantly reduce runoff, leachate and erosion. Polymer efficacy is highly dependent on the physical and chemical properties of the SFM, as well as the mechanism of polymer to SFM adsorption. Increasing the application rate of select treatments lowered leachate volumes, runoff and leachate total sediment loads. Contrary to previous studies, gypsum amendments did not significantly improve polymer efficiency.
This research has added to our understanding of the erodibility and hydrological response of soil and non-soil SFMs. This is the first study to evaluate critically the efficacy of PVALs in controlling erosion from mine-site SFMs. Future studies should continue to optimise NSPASS performance in monitoring changes in surface micro-relief
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