Einstein’s miraculous year

With each passing year, the young Albert Einstein’s achievements in physics in the year 1905 seem to be ever more miraculous. We describe why the centenary of this remarkable year is worthy of celebration.     

Understanding the Nature of Scientific Enterprise (NOSE) through a Discourse with Its History: The Influence of an Undergraduate ‘History of Science’ Course

An appropriate understanding of the nature of the scientific enterprise (NOSE) is a key element of scientific literacy and can arguably be influenced through an exploration of the history of science. An elective, undergraduate History of Science course was organized in the form of small-group discussion-based inquiries into the history of science from ancient to modern times. Group discussions focused on STATEMENTS OF CRITICAL SIGNIFICANCE (SOCS) prepared by individual students on assigned readings prior to each class meeting. Small-group discussions were followed by a synthesis, facilitated by the instructor, of points raised in SOCS and other ideas central to the reading. The overarching goal of these activities was to help students see the multifaceted nature of the scientific enterprise in the context of social, political, cultural, and religious milieu of the time period and the geographic setting within which specific scientific activities and developments took place. The impact of this course on student understanding of the NOSE was assessed through the use of VIEWS ON SCIENCE-TECHNOLOGY-SOCIETY (VOSTS) instrument administered as pre- and post-test. Qualitative data regarding student understanding of the NOSE were furnished by the final exam on the NOSE written in the form of SOCS at the end of semester. Results based on four semesters of the course offering indicate modest gains in student understanding of specific aspects of the NOSE. They are discussed, along with the usefulness of small-group, discussion-based inquiries into the history of science as a way of enhancing scientific literacy during undergraduate science education.     

Design and some applications of extended bandwidth finite gain amplifiers

A general theory is developed for extended bandwidth operation of actively compensated finite gain amplifiers. Designs for three new circuits are given which implement the theory. These circuits employ only operational amplifiers and resistors and their gains depend only on their resistor ratios. Thus they are suitable for IC fabrication. Further in IC technology, the characteristics of the operational amplifiers as well as the resistor ratios track closely with each other with reference to temperature and aging. Thus the extended bandwidth operation of the amplifiers will be available over a wide temperature range as well as under varying aging conditions. Their characteristics can be tuned easily by trimming only two resistors. Applications of the new amplifiers have been considered in RC active filters as well as in inductance simulation schemes. Experimental results are given which closely agree with theoretical predictions. The results also indicate that substantial improvement in the usable bandwidth of the circuits employing the new amplifiers may be expected over those using the conventional design of finite gain amplifiers.     

Effect of vitamin C and E activity on surgically removed cataractous human lens epithelium cells

Oxidative stress has been proposed as a common underlying mechanism of cataractogenesis. Experimental and observational data suggest that micronutrients like vitamin C and vitamin E with antioxidant capabilities may retard the development of age-related cataract. Effect of these factors on lens epithelium cells, center of lens metabolic activities, is not completely elucidated. The aim of present study was to examine the effect of vitamin C and E on surgically removed lens epithelium cells of patients with cataract. Capsulorhexis samples were collected from 170 patients, admitted for cataract surgery. Catalase specific activity was estimated in lens epithelium cells with and without vitamin (C or E) treatment at different concentration for different time duration. Student’s t-test was employed for data analysis. We observed that in ex-vivo condition, a) both vitamin C and E bring about a decrease in catalase activity in lens epithelial cells. b) vitamin C showed toxic effect at high concentration. c) 100μM was the optimum concentration at which both vitamins showed maximum antioxidant activity. It was concluded that both vitamin C and E has direct effect on lens epithelium cells. At optimum concentration, they can reduce oxidative stress in these cells thus can support to prevent or delay cataract development.     

Standard weights and measures

We trace the evolution of standards for weights and measures from olden days to their modern scientific definitions. Even in the era of modern science, standards till recently used to be defined by artifacts. It is only in the last few decades that we have gone over to definitions based on fundamental constants of nature. This has made the standards universally reproducible. The present standards for time, length, and electrical units are all based on physical constants. The mass standard, represented by the prototype kilogram, is the only remaining artifact, but there are promising proposals to replace that in the near future.     

Tyrosinase activity in photosensitive individuals inin-vitro study

A reddish glow localized within the iris was observed in the photographs of some individuals in the dark using an electric-arc flash. On repeated exposure and reprints of the same individuals to photography under similar conditions, the red glow persisted. Studies were under taken to analyze thein vitro effect of cupric ions on the activity of serum tyrosinase. A significant increase in the activity of tyrosinase was observed in the affected individuals as compared to the controls when cupric ion was supplementedin vitro. Studies also confirmed the inhibitory effect of benzoic acid on serum tyrosinase activityin vitro. Our preliminary studies have shown a significant decrease (p<0.001) in tyrosinase activity in the serum of the photosensitive individuals compared to controls which is consistent with the observed red glow on the photographic prints and reprints.