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In this article, the authors present the fabrication of an enzyme-entrapped alginate hollow fiber using a microfluidic device. Further use of enzyme-entrapped alginate hollow fibers as a biocatalytic microchemical reactor for chemical synthesis is also deliberated in this article. To ensure that there is no enzyme leaching from the fiber, fiber surfaces were coated with chitosan. To confine the mobility of reactants and products within the porous hollow fibers the entire fibers were embedded into a transparent polydimethylsiloxane (PDMS) matrix which also works as a support matrix. A vanadium-containing bromoperoxidase enzyme isolated from Corallina confusa was used as a model enzyme to demonstrate the use of these alginate hollow-fiber reactors in bromo-oxidation of phenol red to bromophenol blue at different dye flow rates. Stability of the entrapped enzyme at different temperatures and the effect of the chitosan coating on the reaction conversion were also studied. It was observed that molecules as big as 27 kDa can be retained in the matrix after coating with chitosan while molecules with molecular-weight of around 378 Da can still diffuse in and out of the matrix. The kinetic conversion rate in this microfluidic bioreactor was more than 41-fold faster when compared with the standard test-tube procedure. 相似文献
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Krishnan Gokuladhas Subramaniyan Jayakumar Balan Rajan Ramasamy Elamaran Chengalvarayan Subramani Pramila Mani Gopikrishnan Sasivarman Tamilarasi Thiruvengadam Devaki 《Indian journal of clinical biochemistry : IJCB》2016,31(2):171-184
Liver cancer is the fifth most common cancer and is still one of the leading causes of death world wide, due to food additives, alcohol, fungal toxins, air, toxic industrial chemicals, and water pollutants. Chemopreventive drugs play a potential role in liver cancer treatment. Obviously in the production of anticancer drugs, the factors like poor solubility, bioavailability, biocompatibility, limited chemical stability, large amount of dose etc., plays a major role. Against this backdrop, the idea of designing the chemopreventive nature of bio flavanoid hesperetin (HP) drug conjugated with pegylated gold nanoparticles to increasing the solubility, improve bioavailability and enhance the targeting capabilities of the drug during diethylnitrosamine (DEN) induced liver cancer in male wistar albino rats. The dose fixation studies and the toxicity of pure HP and HP conjugated gold nanoparticles (Au-mPEG(5000)-S-HP) were analysed. After concluded the dose fixation and toxicity studies the experimental design were segregated in six groups for the anticancer analysis of DEN induced HCC for 16 weeks. After the experimental period the body weight, relative liver weight, number of nodules and size of nodules, the levels of tumor markers like CEA, AFP and the level of lipid peroxidation, lipid hydroperoxides and the activities of antioxidant enzymes were assessed. The administration of DEN to rats resulted in increased relative liver weight and serum marker enzymes aspartate transaminase, alanine transaminase, alkaline phosphatase, lactate dehydrogenase, and gamma glutamyl transpeptidase. The levels of lipid peroxides elevated (in both serum and tissue) with subsequent decrease in the final body weight and tissue antioxidants like superoxide dismutase, catalase, reduced glutathione, glutathione peroxidise, and glutathione reductase. HP supplementation (20 mg/kg b.wt) significantly attenuated these alterations, thereby showing potent anticancer effect in liver cancer and the HP loaded gold nanoparticels (Au-mPEG(5000)-S-HP) treated animals shows the better treatment than the pure HP due to the solubility of drug, bioavailability and the target drug delivery of the biodegradable polymer. Histological observations were also carried out, which added supports to the chemopreventive action of the pure HP and HP loaded gold nanoparticles (Au-mPEG(5000)-S-HP) against DEN induction during liver cancer progression. These findings suggest that HP loaded gold nanoparticels (Au-mPEG(5000)-S-HP) shows better efficacy than the pure HP against lipid peroxidation, hepatic cell damage and protects the antioxidant system in DEN induced hepatocellular carcinogenesis. 相似文献
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This review offers a critical analysis of John Ogbu’s Black American Students in an Affluent Suburb: A study of academic disengagement. In his study, Ogbu explains the Black-White achievement gap as one born from the cultural attitudes held by Black middle-class
students toward academics. Despite Ogbu's intent to further the scholarly discussion on this issue, the study falls short
and is itself replete with limitations. Ogbu’s utilization of a deficit-oriented modality and an unsound methodology, coupled
with his failure to critically analyze the interplay of identity formation, culture, and history, together severely restrict
the study’s scope and utility.
* This paper is a revised version of article (Doi:) which appeared online July 7, 2006.
Ogbu, J. Black American Students in an Affluent Suburb: A study of academic disengagement (Lawrence Erlbaum Associates: New Jersey, 2003).
Eddie Comeaux is a Lecturer/Postdoctoral Study in Graduate School of Education and Information Studies at University of California,
Los Angeles, USA. Eddie Comeaux examines comparative race/ethnic, marginality, gender, and class relations with an emphasis
on access and learning opportunities for underrepresented minorities and student athletes in education. Uma M. Jayakumar is
a Doctoral Candidate in Graduate School of Education and Information Studies at University of California, Los Angeles, USA.
Her research interests include: issues of access and retention for graduate students and faculty of color, educational outcomes
of racial diversity, organizational culture and campus racial climate, transformative resistance, service-learning, and higher
education for the public good. 相似文献
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Jayakumar Bose Zed Rengel 《美中教育评论》2009,6(12):29-35
Adult learners are already involved in the process of self-regulation; hence, higher education institutions should focus on strengthening students＇ self-regulatory skills. Self-regulation can be facilitated through formative assessment. This paper proposes a model formative assessment strategy that would complement existing university teaching, and can be used in higher education to promote student-centered self-regulated learning with minimal effort and time input from teachers. Based on this model, a real-world teaching example on writing an essay as a challenge task has also been developed. This model strategy incorporates Nicol and Macfarlane-Dick＇s seven principles of good feedback practice that promotes self-regulation. 相似文献
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Kimberly A. Griffin Uma M. Jayakumar Malana M. Jones Walter R. Allen 《Equity & Excellence in Education》2013,46(2):232-248
Despite the educational challenges African American males face, there is a sizeable population successfully finishing high school and entering college. This study provides an overview of how a national sample of black male freshmen embodied the cognitive, social, and institutional factors related to college access between 1971 and 2004. Data reveal that black, male freshmen today have more affluent family backgrounds, better academic records, and greater confidence in their skills and abilities than their peers who entered college in earlier decades. Trends indicate that men with lower incomes, less confidence, and less ideal academic records are increasingly unlikely to be present on college campuses. 相似文献
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