Monitoring sessile droplet evaporation on a micromechanical device

A bulk acoustic mode micro-electro-mechanical dual resonator platform is utilised to study the evaporation of sub-microliter water droplets from the surface of the resonator. An analytical formulation for the observed frequency shift and the measure dependence of resonant frequency on the modes of evaporation which is consistent with the optically derived data. The resonators access only a thin layer of the liquid through shear contact and, hence, the response is not affected by the bulk mass of the droplet to first order. A relationship between the droplet contact area and the elapsed time was established for the evaporation process and is used to derive a value of the diffusion coefficient of water in air that is found to be in reasonable agreement with literature values. This work introduces a new tool for the electro-mechanical monitoring of droplet evaporation with relevance to applications such as biosensing in liquid samples of sub-microliter volumes.

Cysteine proteinase genes in Indian strain of Haemonchus contortus

The genes of microvillar cysteine proteinases such as hmcp1, hmcp6 and gcp7 of phenotypically distinct morphotypes of female H. contortus having knobbed and linguiform vulvar flaps were cloned and characterized. Complementary DNA (cDNA) was synthesized from total RNA of both the morphotypes. The hmcp1, hmcp6 and gcp7 genes were amplified from cDNA. The amplicons were cloned in pDRIVE T/A cloning vector and sequenced by Sanger's dideoxy method. The nucleotide and deduced amino acid sequences were compared with the USA/UK strain H. contortus cysteine proteinase sequences. The cysteine proteinase genes of Indian strain show considerable variations with USA/UK strains. Our results revealed that Indian strain of H. contortus expresses both UK strain (hmcp1 and 6) and USA strain (gcp7) cysteine proteinases.

Quantitative measurement of the nanoparticle size and number concentration from liquid suspensions by atomic force microscopy

Microscopy techniques are indispensable to the nanoanalytical toolbox and can provide accurate information on the number size distribution and number concentration of nanoparticles (NPs) at low concentrations (ca. ppt to ppb range) and small sizes (ca. <20 nm). However, the high capabilities of microscopy techniques are limited by the traditional sample preparation based on drying a small volume of suspension of NPs on a microscopy substrate. This method is limited by low recovery of NPs (ca. <10%), formation of aggregates during the drying process, and thus, the complete misrepresentation of the NP suspensions under consideration. This paper presents a validated quantitative sampling technique for atomic force microscopy (AFM) that overcomes the above-mentioned shortcomings and allows full recovery and representativeness of the NPs under consideration by forcing the NPs into the substrate via ultracentrifugation and strongly attaches the NPs to the substrate by surface functionalization of the substrate or by adding cations to the NP suspension. The high efficiency of the analysis is demonstrated by the uniformity of the NP distribution on the substrate (that is low variability between the number of NPs counted on different images on different areas of the substrate), the high recovery of the NPs up to 71%) and the good correlation (R > 0.95) between the mass and number concentrations. Therefore, for the first time, we developed a validated quantitative sampling technique that enables the use of the full capabilities of microscopy tools to quantitatively and accurately determine the number size distribution and number concentration of NPs at environmentally relevant low concentrations (i.e. 0.34-100 ppb). This approach is of high environmental relevance and can be applied widely in environmental nanoscience and nanotoxicology for (i) measuring the number concentration dose in nanotoxicological studies and (ii) accurately measuring the number size distribution of NPs; both are key requirements for the implementation of the European Commission recommendation for definition of nanomaterials.

Haemostatic effect of ecliptaalba on albino rabbits

Ecliptaalba (Bhringraj) is an important traditional Indian medicinal plant reported to have antipyretic, anti-inflammatory, antihistaminic, hepatoprotective and anthelmintic effect well documented in literature. In the present study ethanolic leaf extract of eclipta alba (EEEA) was evaluated for its haemostatic activity by their ability to affect the screening test or modify the experimentally induced prolongation of test time on the basis of its folklore claim in normal, aspirin and heparin treated rabbits. The parameters recorded were BT, CT, PT and APTT & platelet count in all the three groups. The study was carried out in 3 parts in different doses 200,400,600 & 800mg/kg. Part-A-study of the haemostatic effect of Ethanolic extract of E. alba (EEEA) in graded doses on normal rabbits. Part-B-study of EEEA in aspirin treated rabbits. Part-C-study of EEEA in heparin treated rabbits. Tranexamic acid was used as the standard drug. Statistical analysis was performed using one way ANOVA & student t test. In normal rabbits EEEA high doses 800mg/k & 600mg/kg exhibited significant reduction in BT & CT (p<0.01). The same doses were found to decrease the aspirin induced increase in BT & heparin induced increase in CT in a significant manner (p<0.01). As decrease in CT might be due to liberation of some active principles from leaves of Ecliptaalba which demonstrated to have anti-haemorrhagic activity against snake bite not affecting any coagulation factor. No significant effect on PT, APPT and platelet count was observed. EEEA exhibited definite haemostatic effect in the above 3 sets of study. Phytochemical analysis and isolation of active principle is essential to carry on beneficial effects from laboratory bench to bedside of patients.

Perception of medical students about pharmacology and scope of improvement

Pharmacology is a subject taught in the medical curriculum in India over a period of one and half years along with pathology, microbiology and forensic medicine. The present study was planned to know the opinion of medical students regarding pharmacology and to assess the proposed teaching schedule and methods of teaching pharmacology. The study was conducted in a private medical college in eastern India among the medical undergraduate students in 5th semester. Total 74 students participated in the study. A pre-designed, pre-tested, semi-structured questionnaire was given to the students and data was collected after one hour. Collected data was compiled, tabulated and analyzed in SPSS (version 16.0). The subject was perceived as interesting and useful by majority of students and most of them were in opinion to integrate pharmacology with the clinical subjects. Lecture in whole class was the most preferred teaching method according to the students and teaching with chalk and board they preferred most. Rational use of medicine, clinical trial, pediatric and geriatric pharmacology are the important topics the students felt to be included in the curriculum. Regular assessment of teaching methods by the students and taking suggestions from the students about improving the teaching method and redesigning the curriculum can help a lot in improving the learning capacity of the medical students and that will give benefit for the society as a whole.