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1.
The article outlines the life and work of Maryam Mirzakhani — the first and the only female winner of the Fields Medal since its inception in 1936. Mirzakhani is an inspiration to young women around the world, to believe in their own abilities and pursue their academic dreams. 相似文献
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Ganesa Yogeeswaran Charles E. Jebaraj Venkataraman Sriram 《Indian journal of clinical biochemistry : IJCB》1999,14(2):220-228
A comparison of the absorbance, enzyme/substrate concentration, reaction efficiency and sensitivity has been made for enzyme-based
clinical chemistry assays, using a conventional colorimeter versus a strip-microwell reader, in order to establish the value
of ultra-microchemical procedure, with reaction volume 87 μl (light path length=0.25 cm). By utilizing commercial kits available
for the quantitation of serum glucose, cholesterol and triglycerides, it has been established that the micro method is highly
cost effective (9–30 fold), reproducible and sensitive. Comparison of blood drawn by a finger prick (capillary) and venipuncture
for normal and pathological specimens show reproducibility between different laboratory technologists and in reference with
the values reported by an accredited reference laboratory. Since the micro method uses very little serum, it is most suitable
for analyses of small smaples, from large population-based field trials. However, the assay range has to be titrated for each
commercial kit to establish the enzyme/substrate equivalence. 相似文献
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M. A. Fallah V. M. Myles T. Kr��ger K. Sritharan A. Wixforth F. Varnik S. W. Schneider M. F. Schneider 《Biomicrofluidics》2010,4(2)
Accurately mimicking the complexity of microvascular systems calls for a technology which can accommodate particularly small sample volumes while retaining a large degree of freedom in channel geometry and keeping the price considerably low to allow for high throughput experiments. Here, we demonstrate that the use of surface acoustic wave driven microfluidics systems successfully allows the study of the interrelation between melanoma cell adhesion, the matrix protein collagen type I, the blood clotting factor von Willebrand factor (vWF), and microfluidic channel geometry. The versatility of the tool presented enables us to examine cell adhesion under flow in straight and bifurcated microfluidic channels in the presence of different protein coatings. We show that the addition of vWF tremendously increases (up to tenfold) the adhesion of melanoma cells even under fairly low shear flow conditions. This effect is altered in the presence of bifurcated channels demonstrating the importance of an elaborate hydrodynamic analysis to differentiate between physical and biological effects. Therefore, computer simulations have been performed along with the experiments to reveal the entire flow profile in the channel. We conclude that a combination of theory and experiment will lead to a consistent explanation of cell adhesion, and will optimize the potential of microfluidic experiments to further unravel the relation between blood clotting factors, cell adhesion molecules, cancer cell spreading, and the hydrodynamic conditions in our microcirculatory system. 相似文献
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New technology adoption in US telecommunications: The role of competitive pressures and firm-level inducements 总被引：1，自引：0，他引：1
In this study we examine the reasons for the differential adoption levels of a new technology, that of electronic switching, across firms in the US telecommunications industry. Using theoretical postulates from the market-structure inducements approach to firm behavior, and the behavioral theory of the firm, we propose that the incentives to adopt a new technology are positively related to the competitive pressures faced by a firm in its micro-market, negatively related to past levels of performance, and positively related to slack availability. Our sample consists of 40 of the largest firms in the industry. We use firm-level data collected for the years 1973, 1978, 1981, 1984, and 1987, and the results indicate strong support for our proposition. Our findings show that, in general, market effects via the mechanism of competitive pressures generated are strong in explaining inter-firm variations in levels of technology adoption in the period since moves to deregulate the industry began; however, the firm-level effects are equally strong, if not stronger, in explaining such variations both in the period leading up to the commencement of deregulatory moves and also immediately thereafter. 相似文献
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A simple and inexpensive method of building a charge meter is discussed and as an application two experiments are suggested. A charge meter can be used for identification and measurement of charges on dielectric media such as teflon, nylon, silk and rubber balloon obtained by method of friction. Teflon and rubber balloon are found to be negatively charged while silk and nylon are found to be positively charged. A charge meter can also be used to measure capacitance of parallel plate capacitors and hence calculate dielectric constant of the medium between its plates. The values of dielectric constant of transparency plastic sheet and plain paper so obtained are 2.71 ± 0.08 and 4.8 ± 0.29. In the last part, the effective capacitance of a capacitor obtained by placing paper and transparency plastic sheet placed one above the other is shown to be equivalent to a series combination of individual paper and transparency plastic sheet capacitors. These experiments can be pedagogical tools for teaching electrostatics. 相似文献
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Measuring forces applied by multi-cellular organisms is valuable in investigating biomechanics of their locomotion. Several technologies have been developed to measure such forces, for example, strain gauges, micro-machined sensors, and calibrated cantilevers. We introduce an innovative combination of techniques as a high throughput screening tool to assess forces applied by multiple genetic model organisms. First, we fabricated colored Polydimethylsiloxane (PDMS) micropillars where the color enhances contrast making it easier to detect and track pillar displacement driven by the organism. Second, we developed a semi-automated graphical user interface to analyze the images for pillar displacement, thus reducing the analysis time for each animal to minutes. The addition of color reduced the Young''s modulus of PDMS. Therefore, the dye-PDMS composite was characterized using Yeoh''s hyperelastic model and the pillars were calibrated using a silicon based force sensor. We used our device to measure forces exerted by wild type and mutant Caenorhabditis elegans moving on an agarose surface. Wild type C. elegans exert an average force of ∼1 μN on an individual pillar and a total average force of ∼7.68 μN. We show that the middle of C. elegans exerts more force than its extremities. We find that C. elegans mutants with defective body wall muscles apply significantly lower force on individual pillars, while mutants defective in sensing externally applied mechanical forces still apply the same average force per pillar compared to wild type animals. Average forces applied per pillar are independent of the length, diameter, or cuticle stiffness of the animal. We also used the device to measure, for the first time, forces applied by Drosophila melanogaster larvae. Peristaltic waves occurred at 0.4 Hz applying an average force of ∼1.58 μN on a single pillar. Our colored microfluidic device along with its displacement tracking software allows us to measure forces applied by multiple model organisms that crawl or slither to travel through their environment. 相似文献
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This special issue examines technology entrepreneurship. Drawing from a rich tradition of research at the interface of the study of entrepreneurship and technological innovation, the articles in the issue examine the effect of environmental conditions on technology entrepreneurship, the processes by which entrepreneurs assemble organizational resources and technical systems, and the strategies used by entrepreneurial firms to pursue opportunities. The papers draw upon a wide variety of empirical evidence, from large sample analyses of archival data to detailed qualitative investigations. Taken together, the papers provide important insights into the major issues facing researchers of technology entrepreneurship today. 相似文献
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The synthesis of polymer nanocomposites is an integral aspect of polymer nanotechnology. By inserting the nanometric inorganic
compounds, the properties of polymers improve and hence this has a lot of application depending upon the inorganic material
present in the polymers. Solvent casting is one of the easiest and less time consuming methods for the synthesis of polymer
nanocomposites. In this article we present different types of polymer composites, methods of synthesis, characterisation techniques
and different applications of polymer composites.
A Lagashetty is Head, Department of Engineering Chemistry, Appa Institute of Engineering and Technology, Gulbarga, Karnataka.
His research interests are synthesis, characterization and applications of nanomaterials and polymer nanocomposites.
A Venkataraman is Head, Department of Materials Science, Gulbarga University, Gulbarga. His research interests are nanomaterials,
nanomaterials as sensors, polymer synthesis and polymer nanocomposites. 相似文献
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Arun Venkataraman 《Resonance》1996,1(2):74-79
The dhole (Cuon alpinus) is a social hunter and a cooperative breeder. Dholes live in packs with rigid hierarchies. Their
social behaviour, hunting strategies and breeding patterns are described in this article. 相似文献