Sample preconcentration inside sessile droplets using electrowetting     

Dileep Mampallil  Dhirendra Tiwari  Dirk van den Ende  Frieder Mugele 《Biomicrofluidics》2013,7(4)

Electrowetting with alternate voltage (AC) creates azimuthal flow vortices inside sessile droplets. These flow vortices can be controlled by introducing pinning sites at the contact line. When the frequency of the applied AC voltage is gradually ramped from a few hundreds of hertz to a few tens of kilohertz the azimuthal flow vortices contract and move towards the contact line near the pinning site. Dispersed particles in the liquid are collected in the center of these vortices leading to an increase in the local particle concentration by up to more than one order of magnitude. We provide a qualitative explanation for symmetry of the flow patterns within the drops and discuss possible scenarios explaining the particle collection and preconcentration.  相似文献   

Rapid and cost-effective fabrication of selectively permeable calcium-alginate microfluidic device using "modified" embedded template method     

Asthana A  Ho Lee K  Kim KO  Kim DM  Kim DP 《Biomicrofluidics》2012,6(1):12821-128219

In this paper, we have presented a non-lithographic embedded template method for rapid and cost-effective fabrication of a selectively permeable calcium-alginate (Ca-alginate) based microfluidic device with long serpentine delay channel. To demonstrate the versatility of the presented method, we have demonstrated two different strategies to fabricate serpentine long delay channels without using any sophisticated microfabrication techniques, in formal lab atmosphere. The procedure presented here, also, enables the preparation of a multilayered microfluidic device with channels of varying dimensions, in a single device without using any sophisticated micromachining instrumentation. In addition, we have also qualitatively studied the diffusion of small and large molecules from a Ca-alginate based microfluidic device and proposed a method to effectively control the out-flow of macro biomolecules from the crosslinked Ca-alginate matrix to create a selectively permeable matrix required for various biological and biomimetic applications, as mentioned in the Introduction section of this work.  相似文献   

Co-inheritance of HbD Iran/Beta Thalassemia IVS1–5 (G?>?C) Trait in a Punjabi Lady with Diabetes     

Vijay S. Bhat  Amit Kumar Mandal  Bobby Mathew 《Indian journal of clinical biochemistry : IJCB》2012,27(2):202-206

The present report describes the molecular study of HbD ^Iran (beta) 22 Glu → Gln associated with β-Thalassemia IVS1–5 (G > C) found in India, and the first case in which mutation has been identified using mass spectrometry. Given the apparent ethnic origin and the mobility of the variant hemoglobin at alkaline pH, hemoglobin D-Punjab would be suspected, but HPLC excluded this possibility. Further characterization of hemoglobinopathy was made by using nondenaturing gel electrophoresis and matrix assisted laser desorption ionization mass spectrometry and IVS1–5 being validated by reverse dot blot hybridization followed by sequencing of the β-globin gene.  相似文献   

Some reflections on mathematics classroom notebooks and their relationship to the public and private nature of student practices     

Michael N. Fried  Miriam Amit 《Educational Studies in Mathematics》2003,53(2):91-112

This article considers students' classroom notebooks, their character and their role in learning. The results presented were found within the frame work of a broader international project, the Learners Perspective Study, whose goal is to identify classroom practice from the students' point of view. Two 8^thgrade classrooms were studied. In each,every lesson over the course of three weeks was videotaped. After each lesson, two students were interviewed and their notebooks entrees for that lesson were photocopied; once a week, the teacher was interviewed as well. From the analysis of the data it became apparent that the notebook in the classroom is a publicobject; it is ever open for inspection and contains only finished work. That it is not a private object in which the student may freely record preliminary ideas, musings, and reflections may affect student learning negatively. The categorization of public and private as a categorization of learning activities is discussed. The relationship between the findings on notebooks and research on writing and classroom journals is discussed; in particular, a connection is made between public and private domains and transactional and expressive writing,respectively. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Teachers' concerns about inclusive education in Ahmedabad,India     

Rina Shah  Ajay Das  Ishwar Desai  Ashwini Tiwari 《Journal of Research in Special Educational Needs》2016,16(1):34-45

This study was undertaken to determine the concerns of primary school teachers about the inclusion of students with disabilities in Ahmedabad, India. A total of 560 teachers, working in government‐run schools, returned the completed survey. A two‐part questionnaire was used in this study. Part 1 gathered information relating to personal and professional characteristics of the teachers. Part 2 was a 21‐item Likert scale titled Concerns about Inclusive Education – Gujarati. The major finding of the study was that the teachers in Ahmedabad were moderately concerned about including students with disabilities in their classrooms. The teachers were most concerned about lack of infrastructural resources and least concerned about lack of social acceptance of students with disabilities in inclusive education classrooms. Significant differences existed in teacher concerns based on the following background variables: gender, qualifications in special education, teaching experience and number of students with disabilities in class. A number of implications are discussed to address teacher concerns for inclusive education in India.  相似文献   

Wavelet transforms: Application to data analysis - II     

Jatan K. Modi  Sachin P. Nanavati  Amit S. Phadke  Prasanta K. Panigrahi 《Resonance》2004,9(12):8-13

We illustrate here, the use of wavelets both in one and two dimensions. We outline the procedure to construct wavelet transform in two dimensions. The method of forward transform, reconstruction and the various steps involved are explained pictorially.  相似文献   

Recurring patterns in the development of high school biology students’ system thinking over time     

Jaklin Tripto  Orit Ben Zvi Assaraf  Miriam Amit 《Instructional Science》2018,46(5):639-680

The goal of this study was to identify and understand the mental models developed by 67 high school biology students as they learn about the human body as a complex system. Using concept maps, it sought to find an external way of representing how students organize their ideas about the human body system in their minds. We conducted a qualitative analysis of four concept maps created by each student throughout the 3-year learning process, which allowed us to identify that student’s systems thinking skills and the development of those skills over time. The improvement trajectories of the students were defined according to three central characteristics of complex systems: (a) hierarchy, (b) homeostasis and (c) dynamism. A comparative analysis of all of our students’ individual trajectories together revealed four typical learning patterns, each of which reflects a different form of development for systems thinking: “from the structure to the process level”, “from macro to micro level”, “from the cellular level to the organism level,” and “development in complexity of homeostasis mechanisms”. Despite their differences, each of these models developed over time from simpler structures, which evolved as they connected with more complex system aspects, and each indicates advancement in the student’s systems thinking.  相似文献   

Student achievement conditioned upon school selection: Religious and secular secondary school quality in Bangladesh     

Mohammad Niaz Asadullah  Nazmul Chaudhury  Amit Dar 《Economics of Education Review》2007,26(6):648

In this paper we present new evidence on the impact of school characteristics on secondary student achievement using a rich dataset from rural Bangladesh. We deal with a potentially important selectivity issue in the South Asian context: the non-random sorting of children into madrasas (Islamic faith schools). We do so by employing a combination of fixed effects and instrumental variable estimation techniques. Our empirical results do not reveal any difference in test scores between religious and secular schools when selection into secondary school is taken into account. However, we document significant learning deficit by gender and primary school type: girls and graduates of primary madrasas have significantly lower test scores even after controlling for school and classroom-specific unobservable correlates of learning.  相似文献   

A Synergistic Role of Myeloperoxidase and High Sensitivity Troponin T in the Early Diagnosis of Acute Coronary Syndrome     

Mihir D. Mehta  Simbita A. Marwah  S. Ghosh  Hitesh Shah  Amit Trivedi  N. Haridas 《Indian journal of clinical biochemistry : IJCB》2016,31(1):75-80

Aim of this study was to evaluate the role of Myeloperoxidase (MPO) and high sensitive Troponin T in the early diagnosis of acute coronary syndrome (ACS). This was a cross sectional study that comprised of 120 individuals of which 75 were cases and 45 healthy controls. On the basis of clinical history and 12 lead electrocardiogram initial diagnosis of ACS was made in the cases. MPO and high sensitive Troponin T (hs-cTnT) was measured in all the individuals. Levels of MPO were significantly higher in patients of ACS as compared to those in control group [medians: 15.40 (95 % CI 11.06–20.84) vs 5.84 (95 % CI 5.50–6.44)]. By taking the cut off as >11.87 U/mL for MPO, its sensitivity was 87 % (95 % CI 73.7–95.1), specificity was 97.3 % (95 % CI 90.6–99.7), positive predictive value was 94.6 % and negative predictive value was 92.6 %. Positive likelihood ratio was 33.0 while negative likelihood ratio was 0.13, whereas the corresponding values in case of hs-cTnT were 95.6 % (95 % CI 85.2–99.5), 61.3 % (95 % CI 49.5–72.6), 59.7 %, 95.8 %, 2.47 and 0.07 by taking cut off as >14 pg/ml. The area under the ROC curves (AUC) of MPO and hscTnT at 0–6 h were 0.971 (95 % CI 0.92–0.99, P < 0.001) and 0.797 (95 % CI 0.71–0.86, P < 0.001) respectively. The logistic model combining the two markers yielded sensitivity, specificity, positive predictive value and negative predictive value of 95.7, 97.3, 98.2 and 93.7 % respectively. It was concluded that MPO and hs-cTnT may be useful tools for risk stratification of ACS and can be used together with better accuracy in the early diagnosis of ACS.  相似文献   

Antioxidant status in neonatal jaundice before and after phototherapy     

Kiran Dahiya  A. D. Tiwari  Vijay Shankar  Simmi Kharb  Rakesh Dhankhar 《Indian journal of clinical biochemistry : IJCB》2006,21(1):157-160

Phototherapy has been related to increased oxidative stress and lipid peroxidation. In the present study, thirty full term jaundiced neonates with appropriate weight were analyzed before and after completion of phototherapy for malondialdehyde (MDA), reduced glutathione (GSH), total thiols, vitamin C and superoxide dismutase (SOD) levels in hemolysate and albumin levels in plasma. These parameters were analyzed in cord blood samples of 20 healthy neonates as control. It was observed that levels of MDA were elevated significantly (p<0.001) in patients as compared to controls and that the levels increased significantly after phototherapy (p<0.001). Levels of SOD were also found to be increased significantly as compared to controls and the levels rose after phototherapy (p<0.001). On the other hand, the levels of non-enzymatic antioxidants such as GSH, total thiols and vitamin C were significantly low (p<0.001) as compared to controls and the levels decreased significantly after phototherapy (p<0.001). The plasma albumin levels also were found to be decreased significantly after phototherapy (p<0.01). Therefore, phototherapy increases oxidative stress and should be used with care.  相似文献