Viscous Flow Behaviour of Karanja Oil Based Bio-lubricant Base Oil.

Karanja oil (KO) is widely used for synthesis of bio-fuel karanja oil methyl ester (KOME) due to its competitive price, good energy values and environmentally friendly combustion properties. Bio-lubricant is another value added product that can be synthesized from KO via chemical modification. In this work karanja oil trimethylolpropane ester (KOTMPE) bio-lubricant was synthesized and evaluated for its viscous flow behaviour. A comparison of viscous flow behaviours of natural KO and synthesized bio-fuel KOME and bio-lubricant KOTMPE was also made. The aim of this comparison was to validate the superiority of KOTMPE bio-lubricant over its precursors KO and KOME in terms of stable viscous flow at high temperature and high shear rate conditions usually encountered in engine operations and industrial processes. The free fatty acid (FFA) content of KO was 5.76%. KOME was synthesized from KO in a two-step, acid catalyzed esterification followed by base catalyzed transesterification, process at 65°C for 5 hours with oil-methanol ratio 1:6, catalysts H2SO4 and KOH (1 and 1.25% w/w KO, respectively). In the final step, KOTMPE was prepared from KOME via transesterification with trimethylolpropane (TMP) at 150°C for 3 hours with KOME-TMP ratio 4:1 and H2SO4 (2% w/w KOME) as catalyst. The viscosity versus temperature studies were made at 0-80°C temperatures in shear rate ranges of 10-1000 s-1 using a Discovery Hybrid Rheometer, model HR-3 (TA instruments, USA). The study found that viscosities of all three samples decreased with increase in temperature, though KOTMPE was able to maintain a good enough viscosity at elevated temperatures due to chemical modifications in its molecular structure. The viscosity index (VI) value for KOTMPE was 206.72. The study confirmed that the synthesized bio-lubricant KOTMPE can be used at high temperatures as a good lubricant, though some additives may be required to improve properties other than viscosity.

Susceptibility Pattern of Enterococci at Tertiary Care Hospital.

The study was aimed to characterize enterococci from various clinical specimens, to determine the antimicrobial susceptibility pattern, and to explore the association between virulence factors and antimicrobial resistance. A total of 283 clinical enterococcal isolates were speciated and subjected to antimicrobial susceptibility testing. Virulence factors (hemolysin, gelatinase, and biofilm production) were detected phenotypically. Of the 283 enterococci isolated, 12 species were identified; predominant species were Enterococcus faecalis (82.33%). High-level gentamicin (HLG) and vancomycin resistance were observed among 55.57% and 6.01% of enteroccal isolates, respectively. All vancomycin-resistant enterococci (VREs) were E. faecalis and had VanA phenotype and genotype. Hemolysin, gelatinase, and biofilm production were seen in 15.90%, 12.36%, and 13.43% of enterococcal isolates, respectively. Vancomycin and HLG resistance were observed in 0.35% and 61.86% of the enterococcal isolates producing virulence factors. Isolates resistant to HLG but susceptible to vancomycin expressed more virulent factors. Further research is required to reveal the complex interplay between drug resistance and virulence factors.

Biomedical Perspective of Electrochemical Nanobiosensor.

Electrochemical biosensor holds great promise in the biomedical area due to its enhanced specificity, sensitivity, label-free nature and cost effectiveness for rapid point-of-care detection of diseases at bedside. In this review, we are focusing on the working principle of electrochemical biosensor and how it can be employed in detecting biomarkers of fatal diseases like cancer, AIDS, hepatitis and cardiovascular diseases. Recent advances in the development of implantable biosensors and exploration of nanomaterials in fabrication of electrodes with increasing the sensitivity of biosensor for quick and easy detection of biomolecules have been elucidated in detail. Electrochemical-based detection of heavy metal ions which cause harmful effect on human health has been discussed. Key challenges associated with the electrochemical sensor and its future perspectives are also addressed.