Organosilicon reagents in natural product synthesis

Berzelius, the Swedish chemist in 1807 introduced the term ‘organic compounds’ as those substances derived from once living organisms (organized systems). Carbon exhibits the property of catenation (formation of chains) and forms a plethora of compounds on earth. Silicon on the other hand which is placed below carbon in the periodic table does not exhibit this property. This article is a brief account of some of the several reagents and classes of compounds encountered in organosilicon chemistry.     

Development of a performance assessment task and rubric to measure prospective secondary school mathematics teachers’ pedagogical content knowledge and skills

The purpose of this paper is to share a performance assessment task and rubric designed to assess secondary school mathematics preservice teachers’ pedagogical content knowledge and skills. The assessment task and rubric were developed in collaboration with five education faculty, four arts and sciences faculty, and four high school teachers over a period of one year. Over this period, the group met more than 15 times and designed an assessment task and rubric to measure secondary school preservice teachers’ pedagogical content knowledge and skills. The assessment task and rubric were piloted at the end of the year and extensively revised using the pilot data. The redesigned task and rubric were successfully carried out in the second and subsequent years. Other teacher education programs can benefit from this assessment of teacher candidates’ pedagogical content knowledge and skills.     

Temporal Trends of Malondialdehyde in Stored Human Plasma

Malondialdehyde (MDA) is widely used as oxidative stress biomarker in biomedical research. Plasma is stored in deep freezers generally till analysis. Effect of such storage on MDA values, which may be variable and prolong, was incidentally observed in the ongoing study which is to estimate oxidative stress with oral iron. Plasma from blood samples of pregnant women (20–30 years age) in third trimester of singleton pregnancy (n = 139), consuming oral iron tablets was stored at −20 °C with intention of MDA estimation, as soon as possible. However logistic problems led this storage for prolonged and variable period (1–708 days). When values of MDA estimated using “Ohkawa” 79 method and readings were plotted against time to check the temporal effect, it showed a hyperbolic curve. Standard deviation (SD) was lowest when samples were tested within 3 weeks time. The samples analyzed within 3 weeks had mean ± SD value of 31.59 ± 26.11 μmol/L, while 123.7 ± 93.97 and 366.5 ± 189.8 μmol/L for samples stored for 1–3 and 4 months to 1 year respectively. Mean ± SD were 539.9 ± 196.8 in the samples store for more than a year. Rate of change in values was also lowest (0.0433 μmol/L/day) in the samples tested within first 3 weeks, which rose to 1.2 μmol/L/day during 3 month’s storage. This rate peaked at storage of 120 days (1.87 μmol/L/day) and fell to 0.502 μmol/L/day in the second year of storage. It is concluded that at −20 °C, only 3 weeks of storage time should be considered valid for fairly acceptable stability in MDA values.     

Effects of some antituberculous and anti-leprotic drugs on cathepsins B,H and L

The cysteine proteinases like cathepsins B, L and H are main hydrolytic enzymes present in lysosomes and play an important role in intracellular protein degradation. Tuberculosis and leprosy, both are tissue- destructive diseases. Main drugs used in chemotherapy of these diseases may inhibit the main lysosomal cysteine proteinases i.e. cathepsins B, L and H released during tissue destruction and thus prevent the further destruction of tissue by these enzymes. So the aim of this study is to see the effect of antituberculous and antileprotic drugs on these proteolytic enzymes. The effect of commonly used antituberculous and antileprotic drugs was screened on the activities of purified brain lysosomal cysteine proteinases namely cathepsins B [EC 3.4.22.1], L [EC 3.4.22.15] and H [EC 3.4.22.16]. Among the antileprotic drugs, only clofazimine inhibited the enzymic activities whereas dapsone had no effect whatsoever. In antituberculous drugs, rifampicin was the most inhibitory while isoniazid had little inhibitory potency. Streptomycin and pyrazinamide did not effect the activities at all. As regards the mechanism of inhibition, clofazimine and isoniazid inhibited the enzymes in a non-competitive manner with K values of 0.25 mM and 5.0 mM for cathepsin B, 0.071 mM and 0.833 mM for cathepsin L and 1.513 mM and 0.885 mM for cathepsin H, While rifampicin could effect in a competitive manner with K_i values of 0.03 mM, 0.125 mM and 0.027 mM for cathepsin B, L and H respectively.     

Gender issues in the university research environment

Recruiting and retaining females within science, engineering and technology continues to challenge many European higher education institutions. This study looks at female self-perceptions relating to effective research work and career progression. Focus groups are used to examine the attitudes and experiences of females and a questionnaire is used to explore perceptions in four main skills areas: group work; communication; personal awareness; project planning and management. The study indicates consistent female concerns on issues pertaining to effective female role models, negative work-role stereotypes and the work–life balance of an academic career. For all four skills areas, the average confidence scores of the female participants fell below those of males, but these differences were only statistically significant for perceptions on group work and communication skills and prior to an intense skills development course. Based on these findings, a student workshop on gender issues has been developed, an outline of which is presented.     

Steroids: A timeless fascination

Steroids are solid organic compounds derived from all life forms, including microorganisms, plants and animals. They obtain their generic name ‘steroids’ from Greek: stereos = solid. Steroids encompass a wide variety of compounds of vital importance to life such as sterols, bile acids, sex hormones, anti-inflammatory corticoid hormones, etc. This article highlights some of the important aspects of cholesterol, the principal sterol of higher animals.     

Transcription through chromatin — Link to diseases and therapeutics

The expression of chromosomal genes is regulated by posttranslational modification of both histone and nonhistone chromatin proteins and ATP-dependent remodeling of chromatin. Dysfunction of the modification and remodeling machineries can lead to several diseases, which include cancer, cardiac hypertrophy, and asthma. Many genetic diseases can also lead to malfunction of the machinery. The enzymes responsible for chromatin organization are the new targets for therapeutics. Inhibitors and activators of histone acetyltransferases and inhibitors of histone deacetylases may serve as new generation drugs.     

A note on growth of superconductivity patents with two new indicators

Patent statistics may be indicative of growth and evolution of technologies in relation to a scientific field or sub-field of research. In this paper annual growth of patents in the field of superconductivity has been studied. The data in five-yearly cumulation have been set against research papers on superconductivity to show comparative growth of basic research and technological development. Two simple indicators have been devised to understand the apparent influence of basic research on technology and trends of relative growth.