Browsing by Author "Tang, Y."
Now showing 1 - 12 of 12
Results Per Page
Sort Options
Item Aflatoxin–albumin adducts and correlation with decreased serum levels of vitamins A and E in an adult ghanaian population(Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment, 2009-01) Tang, L.; Xu, L.; Afriyie-Gyawu, E.; Liu, W.; Wang, P.; Tang, Y.; Wang, Z.; Ankrah, N.A.; Huebner, H.J.; Ofori-Adjei, D.et.alA study of aflatoxin (AF) exposure and the levels of vitamins A and E was carried out with a group of 507 Ghanaian participants. AFB1–albumin adducts (AFB-AA) were measured by radioimmunoassay and vitamins A and E were measured by high-performance liquid chromatography (HPLC). The average level of serum AFB-AA was 0.94 ± 0.64 (range = 0.1–4.44) pmol mg−1 albumin. Mean levels of vitamins A and E were 1.32 ± 0.48 (range = 0.41–4.85) µmol l−1 and 15.68 ± 4.12 (range = 6.35–30.40) µmol l−1, respectively. A significantly negative correlation was found between serum AFB-AA and vitamin A levels (r = −0.110, p = 0.013). An even stronger, significant negative, correlation was found between serum AFB-AA and vitamin E levels (r = −0.149, p < 0.001). Serum AFB-AA levels were statistically higher (median = 0.985 pmol mg−1 albumin) in subjects who had low levels of both vitamins A and E as compared with the levels (median = 0.741 pmol mg−1 albumin) subjects who had high vitamins A and E levels (p trend = 0.001). To verify these findings, blood samples were again collected from 165 of the 507 people 3 months after the initial collection. Significantly negative correlations were confirmed between levels of serum AFB-AA and both vitamins A (r = −0.232, p = 0.003) and E (r = −0.178, p = 0.023). Again, high serum AFB-AA concentrations (median = 1.578 pmol mg−1 albumin) were found in subjects with low levels of vitamins A and E compared with the concentrations (median = 1.381 pmol mg−1 albumin) in subjects with high levels of vitamins A and E (p trend = 0.002). These data show that AF exposure was associated with decreased levels of serum vitamins A and E in high-risk human populations, which may significantly influence the incidence of AF-related adverse health effects. © 2009 Taylor & Francis Group, LLC.Item Beneath a learning management system- Understanding the human information interaction in information systems(Procedia Manufacturing, 2015) Dzandu, M.D.; Tang, Y.Studies on learning management systems have largely been technical in nature with an emphasis on the evaluation of the human computer interaction (HCI) processes in using the LMS. This paper reports a study that evaluates the information interaction processes on an eLearning course used in teaching an applied Statistics course. The eLearning course is used as a synonym for information systems. The study explores issues of missing context in stored information in information systems. Using the semiotic framework as a guide, the researchers evaluated an existing eLearning course with the view to proposing a model for designing improved eLearning courses for future eLearning programmes. In this exploratory study, a survey questionnaire is used to collect data from 160 participants on an eLearning course in Statistics in Applied Climatology. The views of the participants are analysed with a focus on only the human information interaction issues. Using the semiotic framework as a guide, syntactic, semantic, pragmatic and social context gaps or problems were identified. The information interactions problems identified include ambiguous instructions, inadequate information, lack of sound, interface design problems among others. These problems affected the quality of new knowledge created by the participants. The researchers thus highlighted the challenges of missing information context when data is stored in an information system. The study concludes by proposing a human information interaction model for improving the information interaction quality issues in the design of eLearning course on learning management platforms and those other information systems.Item Formation of melt pocket in mantle peridotite xenolith from western Qinling, Central China: Partial melting and metasomatism(Journal of Earth Science, 2010-10) Su, B.; Zhang, H.; Sakyi, P.A.; Qin, K.; Liu, P.; Ying, J.; Tang, Y.; Malaviarachchi, S.P.K.; Xiao, Y.; Zhao, X.; Mao, Q.; Ma, Y.Two types of melt pockets, closed melt pocket (CMP) and open melt pocket (OMP), are recognized from the peridotite xenoliths entrained in the Cenozoic kamafugites in western Qinling (Chinese Source), Central China. The Haoti (Chinese Source) CMPs have a mineral assemblage of olivine+ clinopyroxene+amphibole+K-feldspar, whereas the Baiguan (Chinese Source) CMPs are composed of olivine+clinopyroxene+ilmenite+carbonate. The components of the OMPs are more complicated. In the Haoti OMPs, there are olivine, clinopyroxene, glass, low modal abundances of amphibole, K-feldspar (Kfs), ilmenite, sulfide, chlorite, perovskite, chromite and phlogopite. The Baiguan OMPs contain olivine, clinopyroxene, glass, chlorite and chromite. Compositionally, olivines in the CMPs and OMPs are both apparently depleted in Ni, and those in the OMPs are also depleted in Fe and Mg, and enriched in Ca compared to the primary ones. Clinopyroxenes display large and systematical compositional variations between the CMPs and OMPs, particularly in Al, Cr, Na, Ca and Ti. Glasses are generally depleted in Si compared to the worldwide glasses in melt pockets, although they still have large variations. Amphiboles and K-feldspars have relatively restricted compositional variations. The petrographical observations and mineral chemistry suggest that the Haoti and Baiguan CMPs were generated by the in-situ decompression melting of orthopyroxenes, olivines and clinopyroxenes, and by the addition of minor external K-rich and Ca-rich melt/fluids. The OMPs formed during the latest metasomatic event in the lithospheric mantle beneath the western Qinling. © 2010 China University of Geosciences and Springer-Verlag Berlin Heidelberg.Item Garnet-spinel transition in the upper mantle: Review and interpretation(Journal of Earth Science, 2010-10) Su, B.; Zhang, H.; Asamoah, S.P.; Qin, K.; Tang, Y.; Ying, J.; Xiao, Y.This study carried out a comprehensive review of mantle-derived garnet peridotites on the basis of their garnet-spinel compositional relationships. The P-T estimates of the garnet peridotites of both orogenic and xenolithic derivations confirm previously established two garnet-spinel transition (GST) zones. Results of natural samples and experimental studies of all the garnet peridotites plot below the first GST at low P (<2 GPa). The second GST at high P (6-10 GPa), obtained from the experimental system (MgO-Cr2O3-SiO2), was firstly evidenced from natural samples in this study and may imply a challenge to our understanding of Cr-rich and Al-poor mineral phase transition under ultrahigh P condition. Based on the data and our estimates, we propose the existence of another GST within the garnet peridotite discontinuous zone and a potential spinel-phase peridotite zone in the upper mantle. © 2010 China University of Geosciences and Springer-Verlag Berlin Heidelberg.Item Geochemical syntheses among the cratonic, off-cratonic and orogenic garnet peridotites and their tectonic implications(International Journal of Earth Sciences, 2011-06) Su, B.; Zhang, H.; Tang, Y.; Chisonga, B.; Qin, K.; Ying, J.; Sakyi, P.A.Garnet-bearing mantle peridotites, occurring as either xenoliths in volcanic rocks or lenses/massifs in high-pressure and ultrahigh-pressure terrenes within orogens, preserve a record of deep lithospheric mantle processes. The garnet peridotite xenoliths record chemical equilibrium conditions of garnet-bearing mineral assemblage at temperatures (T) ranging from ~700 to 1,400°C and pressures (P) > 1.6-8.9 GPa, corresponding to depths of ~52-270 km. A characteristic mineral paragenesis includes Cr-bearing pyropic garnet (64-86 mol% pyrope; 0-10 wt% Cr2O3), Cr-rich diopside (0.5-3.5 wt% Cr2O3), Al-poor orthopyroxene (0-5 wt% Al2O3), high-Cr spinel (Cr/(Cr + Al) × 100 atomic ratio = 2-86) and olivine (88-94 mol% forsterite). In some cases, partial melting, re-equilibration involving garnet-breakdown, deformation, and mantle metasomatism by kimberlitic and/or carbonatitic melt percolations are documented. Isotope model ages of Archean and Proterozoic are ubiquitous, but Phanerozoic model ages are less common. In contrast, the orogenic peridotites were subjected to ultrahigh-pressure (UHP) metamorphism at temperature ranging from ~700 to 950°C and pressure >3.5-5.0 GPa, corresponding to depths of >110-150 km. The petrologic comparisons between 231 garnet peridotite xenoliths and 198 orogenic garnet peridotites revealed that (1) bulk-rock REE (rare earth element) concentrations in xenoliths are relatively high, (2) clinopyroxene and garnet in orogenic garnet peridotites show a highly fractionated REE pattern and Ce-negative anomaly, respectively, (3) Fo contents of olivines for off-cratonic xenolith are in turn lower than those of orogenic garnet and cratonic xenolith but mg-number of garnet for orogenic is less than that of off-cratonic and on-cratonic xenolith, (4) Al2O3, Cr2O3, CaO and Cr# of pyroxenes and chemical compositions of whole rocks are very different between these garnet peridotites, (5) orogenic garnet peridotites are characterized by low T and high P, off-cratonic by high T and low P, and cratonic by medium T and high P and (6) garnet peridotite xenoliths are of Archean or Proterozoic origin, whereas most of orogenic garnet peridotites are of Phanerozoic origin. Taking account of tectonic settings, a new orogenic garnet peridotite exhumation model, crust-mantle material mixing process, is proposed. The composition of lithospheric mantle is additionally constrained by comparisons and compiling of the off-cratonic, on-cratonic and orogenic garnet peridotite. © 2010 Springer-Verlag.Item An investigation into knowledge acquisition idiosyncrasies in Ghanaian universities(VINE, 2014-11) Boateng, H.; Dzandu, M.D.; Tang, Y.Purpose – This paper aims to fill the research and knowledge gap in knowledge management studies in Ghana. Knowledge acquisition is one of the unexploited areas in knowledge management literature, especially in the Ghanaian context. This study tries to ascertain the factors affecting knowledge acquisition in Ghanaian universities. Design/methodology/approach – The study used the quantitative approach. The cross-sectional survey was adopted as the research design. A questionnaire consisting of Likert scale questions was used to collect data from the respondents. The items and the constructs were derived from the extant literature. The questionnaire was sent to 350 respondents, out of which 250 were returned fully completed. Data were quantitatively analysed using descriptive methods and factor analysis. Findings – This study provides empirical evidence about the factors affecting knowledge acquisition in Ghanaian universities. Findings from the study show that programme content, lecturers’ competence, student academic background and attitude and facilities for teaching and learning influence knowledge acquisition in Ghanaian universities. Research limitations/implications – Although the study seeks to generalize the findings, this should be cautiously done, as some scholars have advocated for large sample size. Nonetheless, there are some studies that have used sample size less than the one used in this study. Practical implications – The study takes notice of the need for Ghanaian universities to use modern facilities and infrastructures such as electronic libraries and information technology equipment and also provide reading rooms to enhance teaching and learning. Originality/value – Studies looking at knowledge acquisition in Ghanaian universities are virtually non-existent, and this study provides empirical findings on the factors affecting knowledge acquisition in Ghanaian universities. © Emerald Group Publishing Limited.Item Knowledge sharing among employees in Ghanaian Industries(Business Information Review, 2016-09) Boateng, H.; Dzandu, M.D.; Tang, Y.This study investigates the effects of organizational culture (OC) and transformational leadership (TL) style on knowledge sharing (KS). The presence of transformational culture and communal culture in industries in Ghana was ascertained. Survey research design was used. The simple random sampling technique was used to select the sample size of the study. Questionnaire was used for the data collection. Data was analysed using descriptive statistics and multiple regression. The findings show presence of communal culture in industries in Ghana. Again, it was found that OC is a significant predictor of KS. The study also found that leadership in industries lack TL qualities. Furthermore, TL insignificantly contributes to KS.Item Knowledge Sharing Idiosyncrasies of University Students in Ghana(International Conference on Informatics and Semiotics in Organisations, 2014-05) Dzandu, M.D.; Boateng, H.; Tang, Y.This study explored the factors affecting knowledge sharing behaviour of students in a higher institution of learning. Using a model derived from the Social Cognitive Theory and the Theory of Reason Action, six hypotheses were tested from a cross-sectional data collected from 371 undergraduate students on a 4-year degree programme in the University of Ghana. Five out of the six hypotheses were supported. The results showed that the knowledge sharing behaviour (KSB) of the students was significantly related to five of the human and environmental factors (F=639.9, df=5, 290, p<0.05) with a co-efficient of variation of R2=0.917 (91.7%). The knowledge sharing behavior of the students was, however, not significantly dependent on their personal characteristics. The study makes a case for increased attention in understanding the human and environmental factors of knowledge sharing since knowledge sharing is largely a people activity shaped by cultureItem Monitoring of polypeptide content in the solid‐state fermentation process of rapeseed meal using NIRS and chemometrics(Journal of Food Process Engineering, 2018-08) Xing, Z.; Hou, X.; Tang, Y.; He, R.; Mintah, B.K.; Dabbour, M.; Ma, H.This study combined Fourier transform-near infrared (NIR) spectroscopy and chemometrics, to monitor changes in peptide content during the solid-state fermentation of rapeseed meal. A NIR calibration model was established by performing spectral scanning on 81 samples and using interval partial least squares. The results showed that coefficient of determination (R2) and root mean square error of cross-validation could achieve 0.9441 and 0.654 g/L for polypeptide content. Furthermore, the predicted and experimental values of the two parameters in an external validation set showed similar changes throughout the fermentation. Practical applications: The results show that near-infrared spectroscopy is a promising method to monitor the chemical parameters of rapeseed meal during solid fermentation. © 2018 Wiley Periodicals, Inc.Item NovaSil clay intervention in Ghanaians at high risk for aflatoxicosis: II. Reduction in biomarkers of aflatoxin exposure in blood and urine(Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment, 2008-05) Wang, P.; Afriyie-Gyawu, E.; Tang, Y.; Johnson, N.M.; Xu, L.; Tang, L.; Huebner, H.J.; Ankrah, N.A.; Ofori-adjei, D.et.alThe efficacy of NovaSil clay (NS) to reduce aflatoxin (AF) biomarkers of exposure was evaluated in 656 blood samples and 624 urine samples collected from study participants during a 3-month phase IIa clinical intervention trial in Ghana. NS was delivered before meals via capsules. Serum AFB1–albumin adduct was measured by radioimmunoassay and urinary AFM1 metabolites were quantified by immunoaffinity-high-performance liquid chromatography (HPLC)-fluorescence methods. Levels of AFB1–albumin adduct in serum samples collected at baseline and at 1 month were similar (p = 0.2354 and p = 0.3645, respectively) among the placebo (PL), low dose (LD, 1.5 g NS day−1), and high dose (HD, 3.0 g NS day−1) groups. However, the levels of AFB1–albumin adduct at 3 months were significantly decreased in both the LD group (p < 0.0001) and the HD group (p < 0.0001) compared with levels in the PL group. Levels of AFM1 in urine samples collected at baseline and at 1 month were not statistically different among the three study groups. However, a significant decrease (up to 58%) in the median level of AFM1 in samples collected at 3 months was found in the HD group when compared with the median level in the PL group (p < 0.0391). In addition, significant effects were found for dose, time, and dose–time interaction with serum AFB1–albumin adduct and dose–time interaction with urinary AFM1 metabolites. The results suggest that capsules containing NS clay can be used to reduce effectively the bioavailability of dietary AF based on a reduction of AF-specific biomarkers. © 2008 Taylor & Francis Group, LLC.Item Thermophilic solid-state fermentation of rapeseed meal and analysis of microbial community diversity(LWT - Food Science and Technology, 2019-08-20) Mintah, B.K.; Hou, X.; Dai, C.; Tang, Y.; Xing, Z.; Dabbour, M.; Ding, Q.; He, R.; Ma, H.To reduce the high cost caused by steam sterilization of fermentation substrates and equipments in mesophilic solid-state fermentation of rapeseed meal (RM), a thermophilic protease-producing strain RM-2 from RM was isolated and employed in thermophilic solid-state fermentation of unsterilized RM for polypeptide preparation. The isolate was identified as Geobacillus stearothermophilus by appearance of colonies and microscopic observation as well as 16S rDNA sequencing. The highest yield of polypeptide (9.67%) was obtained by RM-2 at 50% moisture content, 55 °C and 24 h fermentation time. Analysis of microbial community diversity in fermented RM revealed Geobacillus stearothermophilus as dominant strain inhibiting most mesophilic microorganisms. Thermophilic solid-state fermentation on RM improved the yield of rapeseed polypeptide, as well as the utilization rate of substrate. The application of this technology (thermophilic solid-state fermentation) would be environmentally friendlier and energy-saving to industry.Item Ultrasound assisted enzymolysis of sunflower meal protein: Kinetics and thermodynamics modeling(Journal of Food Process Engineering, 2018-09) Dabbour, M.; He, R.; Mintah, B.; Tang, Y.; Ma, H.This study examined the effect of dual‐frequency ultrasound (DFU) pretreatment on thermodynamics and kinetics of sunflower‐meal protein (SMP) using alcalase to improve efficiency in enzymolysis process. The concentration of hydrolyzed protein and kinetic parameters after traditional pretreatment (control) were investigated and compared with DFU‐assisted enzymolysis. The results indicated that DFU‐pretreatment enhanced SMP‐enzymolysis efficiency at different substrate and enzyme concentrations, temperature, and pH. Kinetics analysis showed DFU‐pretreatment reduced the Michaelis constant by 11.29%, while the apparent breakdown rate constant increased by 1.96%, indicating DFU‐pretreatment improved the affinity among substrate and enzyme. The rate constants for DFU‐pretreatment were increased by 45.96, 26.92, 21.14, and 27.89% at 293, 303, 313, and 323 K, respectively (p < .05). On Arrhenius kinetics, DFU reduced the activation energy, enthalpy and entropy by 24.28, 26.13, and 9.10%, respectively (p < .05). DFU had slight influence on Gibbs‐free energy when temperature increased from 293 to 323 K.