Vipin Sharma

Hypocholesterolaemic effects of Terminalia arjuna tree bark.

Diet-induced hyperlipidaemic rabbits were given 50% ethanolic extract of Terminalia arjuna tree bark in doses of 100 mg/kg (Group B, n = 6) and 500 mg/kg (Group C, n = 6) and compared with controls (Group A). At 60 days of intervention in Groups A, B and C mean +/- S.E.M. total cholesterol was 574 +/- 61, 320 +/- 29 and 217 +/- 44 mg/dl, respectively (P < 0.01); LDL cholesterol was 493 +/- 57, 271 +/- 30 and 162 +/- 44 mg/dl (P < 0.01); HDL cholesterol was 59 +/- 7, 36 +/- 3 and 35 +/- 4 mg/dl (P = n.s.); triglyceride was 108 +/- 13, 67 +/- 6 and 101 +/- 26 mg/dl (P = n.s.); cholesterol/HDL ratio was 10.1 +/- 1.3, 9.2 +/- 1.1 and 6.1 +/- 1.0 (P = n.s.); and LDL/HDL ratio was 8.7 +/- 1.3, 7.8 +/- 1.1 and 4.5 +/- 1.0 (P < 0.01). The extract did not adversely affect biochemical tests of liver and renal function and haematological parameters.

Wear Behavior of Dual Particle Size (DPS) Zircon Sand Reinforced Aluminum Alloy

The present investigation aims to find the combined effect of coarse and fine size particle reinforcement of zircon sand in aluminum alloy LM13 on the wear behavior. The composites are fabricated by varying the reinforcement of fine and coarse size zircon sand particles and compared with the single size reinforcement. Coarse and fine particle zircon sand of 106–125 and 20–32-μm size, respectively, are used in this study. The wear test was carried out on pin-on-disc machine. Microhardness measurement was done for developed composites. Wear track and debris are analyzed by SEM to study the wear mechanism. Line profile and EDS analysis is also done to validate the microstructural results. Study reveals that a combination of 3xa0% fine and 12xa0% coarse particle reinforced composite exhibits better wear resistance while 3xa0% coarse and 12xa0% fine particle reinforcement decreases the wear resistance. It is also observed that zircon sand particles provide effective nucleation site for the eutectic silicon. Microstructural examination shows globular and finely distributed eutectic silicon in the vicinity of the reinforced particles.

Microstructural and wear behavior of dual reinforced particle (DRP) aluminum alloy composite

The present investigations are a comparative study of single and dual reinforcement particles on microstructural features and wear behavior in LM-13 aluminum–silicon alloy. Silicon carbide and zircon sand particles of 20–32xa0μm are reinforced in the alloy by two-step stir casting method. Wear study reveals that the dual particle reinforcement enhances the wear resistance as compared to single particle reinforcement if mixed in a definite proportion. Study also indicate that a combination of 15xa0% reinforcement of zircon sand and silicon carbide particles in the ratio of 1:3 into the composite exhibits better wear resistance as compared to other combination.

Correlation of Reinforced Ceramicparticle’s Nature and Size with Microstructure and Wear Behavior of Al-Si Alloy Composite

The present study aims to analyze the effect of particle size on nature of microstructural features and wear behavior of composite. Stir casting route has been adopted for the fabrication of aluminium matrix composite using Al-Si LM13 piston alloy. Composites have been developed by varyig the size of zircon sand particles while keeping the SiC particles of same size. Microstructural analysis shows that SiC has a pronounced effect on the microstructure and eutectic silicon refinement. Microstructure evolution is mainly governed by the thermal conductivity difference between two phase’s i.e. ceramic particle and alloy matrix. The dendritic ripening is also observed in the composites in microstructural study. EDS analysis reveals the formation of mechanically mixed layer in the composites enabling better wear properties. Fine size zircon sand particle reinforced composite exhibits better wear resistance than coarse particle at same weight percentage of reinforcement. The SiC reinforcement is better as compared to zircon sand particles for enhancing wear resistance of the composite. Silicon carbide refines the eutectic silicon whereas zircon sand provides good interfacial bonding. SEM examination of worn surface and wear debris shows that the various wear mechanism are involved in material removal.

Comparison of intravenous Magnesium Sulphate with intrathecal Magnesium Sulphate for post- operative analgesia in orthopaedic patients undergoing extracapsular hip fracture surgery

Background: Magnesium sulphate (MgSO 4 ) N methyl D aspartate receptor antagonist has the potential to be an ideal adjuvant for postoperative analgesia via intrathecal or intravenous route. The aim of the study was, we compared the efficacy of two routes of MgSO 4 (Intravenous vs intrathecal) as an adjuvant to bupivacaine in subarachnoid block (SAB). Methods: Ninety, American Society of Anesthesiologists physical status 1 or 2 patients, aged 20-60 years, scheduled for hip surgeries under SAB were recruited in department of Anaesthesia and Dept. of Orthopaedics. Patients in group 1 (n=29) received intrathecal 0.5% (H) bupivacaine 15 mg with 0.1 ml of normal saline and 250 ml 0.9% normal saline intravenous 30 minutes before giving SAB. Group 2 (n=30) patients received intrathecal 0.5% bupivacaine 15mg with 0.1 ml of normal saline and 50mg/kg of magnesium sulphate in 250 ml normal saline intravenous 30minutes before giving SAB. In Group 3 (n=30) patients received intrathecal 0.5% (H) bupivacaine 15 mg with 50mg (0.1ml) magnesium sulphate and 250 ml 0.9% normal saline intravenous 30 minutes before giving SAB. They were evaluated for block characteristics, visual analogue scale at various time intervals up to 24 hours and total rescue analgesic and duration of postoperative analgesia were noted. Results: Intravenous magnesium sulphate had maximum pain free interval, lower pain scores, longer sensory and motor blockade and less requirement of rescue analgesia as compared to the patients in intrathecal group or control group (P<0.05). Conclusions: Intravenous magnesium sulphate was more effective as compared to intrathecal route with regards to the pain scores and in providing postoperative analgesia.