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1.
In this article we discuss an exciting experiment in non-linear dynamics. This provides an imaginative platform for bringing in chemical, physical, biological, mathematical and computational sciences together. There are implications for earth sciences as well. B M Deb is a theoretical chemist who has been designing experiments for chemistry teaching laboratories for more than thirty years. Mainak Sadhukhan, Sudarson Sekhar Sinha and Sucheta Sengupta were students of PBIR-Chemical Sciences. Ranjit Biswas is a physical chemist working on both theory and experiment in chemical dynamics.  相似文献   
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ABSTRACT

Science, Technology, Engineering and Mathematics (STEM) education garnered significant attention in recent years and has emerged as a key field of research globally. The goal of this article is to offer a critical review of how STEM education and its transdisciplinarity were defined and/or positioned in empirical studies published during the early formulation of the field. In particular, we sought to identify how these studies conceptualise learners and learning and portray the underlying assumptions in light of the macrosystemic discourses that often serve as ideological forces in shaping research and practice of STEM education. We examined 154 peer-reviewed articles published between January 2007 and March 2018 and analysed them along several emergent dimensions: their geospatial focus, focal disciplinary areas, methodological and theoretical assumptions, and major findings. Grounded in a critical transdisciplinary perspective, we used critical discourse analysis to identify how macrosystemic and institutionalised forces – overtly and implicitly – shape what counts as STEM education research, including its goals and conceptualisations of learners and learning. Our analysis highlights the need for aesthetic expansion and diversification of STEM education research by challenging the disciplinary hegemonies and calls for reorienting the focus away from human capital discourse.  相似文献   
3.
Preanalytical errors contribute to a large proportion of total laboratory errors. In order to achieve continuous laboratory improvement, it is important to focus on all phases of patient specimen testing i.e. preanalytical, analytical and post-analytical. With large variations in the way venous blood specimens are collected using diverse devices in the country, the effect of such practices on specimen quality is not known. The purpose of this study was to monitor fourteen specimen preanalytical quality indicators in order to compare the usage of evacuated blood collection devices with needle and syringe open collection using either disposable tubes or re-washed glass vials. The study involved 26638 patient specimens assessed over a period of 6 months. The results demonstrated that evacuated closed blood collection resulted in an approximate 100-fold reduction in the incidence of hemolysis in samples. Similarly, there was a 200-fold reduction in incidence of insufficient specimen quantity while using evacuated collection system. It was also found that incidence of specimen contamination, improper volume of sample collected, and specimen spillage was also lower when the evacuated collection system was used. Further, it was also observed that the facility with a laboratory information system demonstrated much lower specimen identification and related errors. The observed results clearly demonstrate that the usage of the evacuated blood collection system resulted in improvement of preanalytical specimen quality as compared to needle and syringe usage.  相似文献   
4.
The increasing use of light‐complexioned black models with Caucasian features in ads has been roundly criticized. This study was designed to test if black female models with Caucasian features are more effective in ads than black models with “classical” features. A 2×2 factorial design was used with two models (mixed‐race and “classical” black) and two products (beauty‐related and beauty‐unrelated). MANOVA tests showed that regardless of the type of product, the type of model did not make a significant difference on the measures of advertising effectiveness. Neither were the interaction effects significant.  相似文献   
5.
This article, as the title suggests, highlights the contributions of Edison in lighting up the world and harnessing electricity to do the job.  相似文献   
6.
Nicotine, responsible for the addictive properties of tobacco, is widely used in nicotine replacement therapy for tobacco use cessation. We investigated the time-dependent effect of treatment with nicotine on the tumor suppressor, DNA repair and immune responses. Swiss Albino mice (laca strain) of both sexes received nicotine dissolved at a dose of 100 µg/ml in 2% sucrose for 24 weeks, by oral gavage, while age- and gender-matched controls received only 2% sucrose for the same period. Nicotine-treated and control mice were sacrificed 6, 16 and 24 weeks post-treatment, and their tissues evaluated for alterations in histology, oxidative stress, TNF-α levels, nitric oxide (NO) and myeloperoxidase (MPO) release, tumor suppressor response and DNA repair response. Statistical significance of results was determined using Students’ t test. The tissues of nicotine treated mice exhibited a large number of multinucleated and binucleated cells, enlarged nuclei and non-uniform distribution of cells, significant increase in expression of TNF-α gene and serum TNF-α, and time-dependent significant increase in lipid peroxidation, protein carbonylation, NO and MPO release when compared to age-and gender-matched controls. The mRNA expression of the tumor suppressor gene p53, its primary regulator Mdm2, and the DNA repair genes Brca2 and Ape1 were significantly elevated, but the corresponding protein levels remained largely unaltered. In conclusion, treatment with nicotine caused oxidative stress and inflammation which can cause widespread cellular damage from the very onset of treatment, without subverting the tumor suppressor and DNA repair responses.Electronic supplementary materialThe online version of this article (10.1007/s12291-020-00903-8) contains supplementary material, which is available to authorized users.  相似文献   
7.
Sujan Sengupta 《Resonance》2016,21(7):641-652
Is there life anywhere else in the vast cosmos? Are there planets similar to the Earth? For centuries, these questions baffled curious minds. Either a positive or negative answer, if found one day, would carry a deep philosophical significance for our very existence in the universe. Although the search for extra-terrestrial intelligence was initiated decades ago, a systematic scientific and global quest towards achieving a convincing answer began in 1995 with the discovery of the first confirmed planet orbiting around the solar-type star 51 Pegasi. Since then, astronomers have discovered many exoplanets using two main techniques, radial velocity and transit measurements. In the first part of this article, we shall describe the different astronomical methods through which the extrasolar planets of various kinds are discovered. In the second part of the article we shall discuss the various kinds of exoplanets, in particular about the habitable planets discovered till date and the present status of our search for a habitable planet similar to the Earth.  相似文献   
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9.
Bacterial resistance to antibiotics poses a serious challenge to the prospect of chemotherapy. Rational use of antibiotics is most desirable but it cannot provide a permanent solution to the problem. In this article the biochemical and genetic basis of antibiotic resistance in bacteria is discussed with examples. The non-clinical aspects of antibiotic-resistance are also dealt with in brief.  相似文献   
10.
Despite various studies with conflicting results, the effect of thyroid hormones on lipids and insulin levels in dysthyroidism is of great interest. This case control study was aimed to perceive the existence of IR and dyslipidemia in mild subclinical hypothyroid subjects (TSH ≤ 9.9 µIU/ml) as compared to their age and gender matched euthyroid controls. Basic demographic information like height, weight was recorded. Serum samples of all the subjects were assayed for thyroid profile, lipid profile, blood glucose, HbA1C and insulin. BMI and insulin resistance was calculated. Compared to controls patients with mild subclinical hypothyroidism demonstrated hyperinsulinemia and dyslipidemia observed by the higher LDL cholesterol. A significantly positive correlation was observed for HOMA-IR with TSH and LDL cholesterol. Hence, even in the mild subclinical hypothyroid state assessment of thyroid function should be combined with estimation of plasma glucose, insulin and serum lipids to monitor and prevent its associated effects.  相似文献   
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