Transport of particles and microorganisms in microfluidic channels using rectified ac electro-osmotic flow     

Wu WI  Selvaganapathy PR  Ching CY 《Biomicrofluidics》2011,5(1):13407

A new method is demonstrated to transport particles, cells, and other microorganisms using rectified ac electro-osmotic flows in open microchannels. The rectified flow is obtained by synchronous zeta potential modulation with the driving potential in the microchannel. Experiments were conducted to transport both neutral, charged particles, and microorganisms of various sizes. A maximum speed of 50 μm∕s was obtained for 8 μm polystyrene beads, without any electrolysis, using a symmetrical square waveform driving electric field of 5 V∕mm at 10 Hz and a 360 V gate potential with its polarity synchronized with the driving potential (phase lag=0°).  相似文献   

Effect of pulse direct current signals on electrotactic movement of nematodes Caenorhabditis elegans and Caenorhabditis briggsae     

Rezai P  Salam S  Selvaganapathy PR  Gupta BP 《Biomicrofluidics》2011,5(4):44116-441169

The nematodes (worms) Caenorhabditiselegans and Caenorhabditisbriggsae are well-known model organisms to study the basis of animal development and behaviour. Their sinusoidal pattern of movement is highly stereotypic and serves as a tool to monitor defects in neurons and muscles that control movement. Until recently, a simple yet robust method to initiate movement response on-demand did not exist. We have found that the electrical stimulation in a microfluidic channel, using constant DC electric field, induces movement (termed electrotaxis) that is instantaneous, precise, sensitive, and fully penetrant. We have further characterized this behaviour and, in this paper, demonstrate that electrotaxis can also be induced using a pulse DC electric signal. Worms responded to pulse DC signals with as low as 30% duty cycle by moving towards the negative electrode at the same speed as constant DC fields (average speed of C. elegans?=?296?±?43?μm/s and C. briggsae?=?356?±?20?μm/s, for both constant and pulse DC electric fields with various frequencies). C. briggsae was found to be more sensitive to electric signals compared to C. elegans. We also investigated the turning response of worms to a change in the direction of constant and pulse DC signals. The response for constant DC signal was found to be instantaneous and similar for most worms. However, in the case of pulse DC signal, alterations in duty cycle affected the turning response time as well as the number of responding worms. Our findings show that pulse DC method allows quantitative measurement of response behaviour of worms and suggest that it could be used as a tool to study the neuronal basis of such a behaviour that is not observed under constant DC conditions.  相似文献   

Promoting higher order thinking skills using inquiry-based learning     

G. V. Madhuri  V. S.S.N Kantamreddi  L. N.S. Prakash Goteti 《European Journal of Engineering Education》2012,37(2):117-123

Active learning pedagogies play an important role in enhancing higher order cognitive skills among the student community. In this work, a laboratory course for first year engineering chemistry is designed and executed using an inquiry-based learning pedagogical approach. The goal of this module is to promote higher order thinking skills in chemistry. Laboratory exercises are designed based on Bloom's taxonomy and a just-in-time facilitation approach is used. A pre-laboratory discussion outlining the theory of the experiment and its relevance is carried out to enable the students to analyse real-life problems. The performance of the students is assessed based on their ability to perform the experiment, design new experiments and correlate practical utility of the course module with real life. The novelty of the present approach lies in the fact that the learning outcomes of the existing experiments are achieved through establishing a relationship with real-world problems.  相似文献   

Reading and writing skills in multilingual/multiliterate aphasics: Two case studies     

Chengappa  Shyamala  Bhat  Sapna  Padakannaya  Prakash 《Reading and writing》2004,17(1-2):121-135

Reading and writing deficits in twomultilingual speakers of Kannada, Hindi andEnglish are described. Disorders of the twopatients (Mr G and Ms S) had differentetiologies. Mr G had severe alexia withagraphia in English as well as in Kannada andHindi. Ms S exhibited dissociation across thelanguages, showing symptoms of surface dyslexiain English and mild dyslexia in Kannada. Bothpatients were tested on the Western AphasiaBattery and on tests developed by Coltheart.Their test performance is described anddiscussed in the context of orthographicdifferences between English and various Indianlanguages.  相似文献   

Capping drugs: Development of prodrugs     

H.?Surya?Prakash?RaoEmail author 《Resonance》2003,8(2):19-27

It is clear from the foregoing, that the development of prodrugs promises to be a very effective method for treatment of diseases in the future. This approach has several advantages over conventional drug administration. Site specificity is central to the prodrug development strategy. Even though at present prodrugs are not prevalent in clinical use, in future there will be prodrugs for every known drug to make them effective in treatment. Drug discovery and prodrug development appear to be complementary for the generation of target specific medicines of future. At present the research in this area is at a nascent stage due to lack of information regarding all the enzymes or receptors most suitable for targeting purposes. As the unravelling of the microbiological details of the affected targets become clear, prodrug development will surely decrease side/toxic effects of drugs and also trigger development of more potent primary drugs.  相似文献   

Using Big Data to Examine the Relationship Between Facebook Engagement and Local Newscast Ratings     

Rachna Prakash 《Journalism Practice》2020,14(5):574-591

ABSTRACT

Local TV news stations regularly post to social media, on Facebook in particular, in an effort to engage audiences, but little is known about the effect of this practice on newscast ratings. We examine the relationship between engagement on Facebook and newscast ratings using data from Shareablee and Nielsen respectively in regression analyses. We find that Facebook engagement does not cannibalize TV ratings, rather there is a clear positive relationship between the two. However, further analyses suggest that this relationship may be driven by interest in news events or other market-wide factors that result in both Facebook engagement and viewership increasing or decreasing simultaneously.  相似文献   

Cognitive preferences of secondary science teachers in India: The example of uttar pradesh     

Jyoti Prakash Bagchi  Haseen Uddin 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》1990,36(4):453-467

Earlier studies on cognitive preferences have concentrated on students, whereas the subjects here are teachers of science. The study seeks to compare how cognitive preferences differ in groups of secondary school teachers identified by type of curriculum taught (traditional vs. enquiry-oriented), gender, length of teaching experience, and educational qualification.The Combined Cognitive Preference Inventory compiled by Pinchas Tamir was applied to 103 subjects drawn by random cluster sampling from urban schools. Inferential statistical analysis was employed, with a matched group design. With few exceptions the overall pattern of cognitive preferences that emerged for all the groups is Recall-Principles-Application-Questioning. These results do not confirm anticipated differences, and bring home the fact that teachers' congnitive preferences remain constant. The implications for implementation of innovative curricula and teacher education are discussed.

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Zusammenfassung Frühere Studien über kognitive Präferenzen konzentrierten sich auf Studenten, während Thema dieses Artikels Lehrer im wissenschaftlichen Bereich sind. Die Studie will einen Vergleich anstellen, wie kognitive Präferenzen sich nach Gruppen von Sekundarschullehrern unterscheiden, die nach verschiedenen Kriterien wie Art des unterrichteten Curriculums (traditionell gegen Frageorientierte), Geschlecht, Länge der Berufserfahrung und Qualifikationen bestimmt wurden.Das von Pinchas Tamir aufgestellte zusammengefaßte Inventar der kognitiven Präferenzen wurde bei 103 Lehrern an städtischen Schulen durch Zufallsstichprobenerhebung angewandt. Eine zu Schlußfolgerungen führende statistische Analyse wurde erstellt, und zwar mit einem matched group design (parallelisiertes Gruppendesign). Das sich mit wenigen Ausnahmen für alle Gruppen ergebende Grundmuster der kognitiven Präferenzen ist Erinnerung-Grundsätze-Anwendung-Fragestellung. Diese Ergebnisse bestätigen die angenommenen Unterschiede nicht, und sie lassen erkennen, daß die kognitiven Präferenzen der Lehrer konstant bleiben. Die Auswirkungen auf die Einführung innovativer Curricula und auf die Lehrerausbildung werden diskutiert.

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Résumé Les études effectuées sur les préférences cognitives étaient focalisées au départ sur les apprenants, tandis que les questions étudiées ici portent sur les enseignants de science. La présente étude tente d'établir une comparaison entre les préférences cognitives des différents groupes d'enseignants du secondaire qui ont été identifiés d'après le type de programme enseigné (programme traditionnel contre programme orienté vers la recherche), le sexe, la longueur de l'expérience didactique et les qualifications pédagogiques.L'inventaire des préférences connitives combinées compilé par Pinchas Tamir a été appliqué à 103 matières sélectionnées au hasard à partir d'un échantillonnage d'écoles urbaines. On a employé l'analyse statistique déductive, avec un plan de groupe correspondant. Mises à part quelques exceptions, la structure générale des préférences cognitives qui s'est dégagée pour tous les groupes est la suivante: Rappel-Principes-Application-Interrogation. Ces résultats ne corroborent pas les différences anticipées et font comprendre le fait que les préférences cognitives des enseignants sont constantes. On examine les implications de ces résultats pour la mise en oeuvre de programmes d'étude novateurs et la formation des formateurs.

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HIV/AIDS research in India: A bibliometric study     

Swapan Kumar Patra  Prakash Chand 《Library & information science research》2007

This article looks at the growth over time of Indian AIDS research output based on bibliographic data from PubMed and Web of Science. Authorship distribution was examined using Lotka's law. Bradford's law of scattering was used to identify core journals. The study identifies active institutions and statewide distributions of Indian AIDS research output. The yearly analysis of data shows that there is a rapid growth of literature from 1992 onwards. Still, in an international sense, relative productivity of India is low and requires more focused research and development.  相似文献   

Non-fiction: Gloriously irresponsible?     

Ravi Mirchandani 《Publishing Research Quarterly》1998,14(2):36-40

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Comparison of lipid profile and antioxidant enzymes among south Indian men consuming coconut oil and sunflower oil     

P. Sabitha  Kannan Vaidyanathan  D. M. Vasudevan  Prakash Kamath 《Indian journal of clinical biochemistry : IJCB》2009,24(1):76-81

In this study, we compared the lipid profile and antioxidant enzymes of normal and diabetic subjects consuming two different types of oil as cooking medium. 70 normal, healthy subjects were taken as controls and 70 subjects with Type 2 diabetes were recruited in patient group. Each group was further subdivided into two subgroups of 35 subjects each, consuming coconut oil and sunflower oil respectively as cooking medium. Samples of blood were collected and analyzed for serum total cholesterol, triacylglycerols, and cholesterol in lipoprotein fractions. Total glutathione and glutathione peroxidase were measured in erythrocytes and superoxide dismutase in serum. Triacylglycerols, LDL and VLDL cholesterol levels were high in the diabetic subjects compared to the controls. Total glutathione and glutathione peroxidase values showed significant decrease in diabetic subjects as compared to the controls, while superoxide dismutase values showed significant difference between coconut oil consuming groups. Though lipid profile parameters and oxidative stress were high in Type 2 diabetic subjects compared to controls, no pronounced changes for these parameters were observed between the subgroups (coconut oil vs. sunflower oil).  相似文献