AN ETHNO-PHARMACOLOGICAL EVALUATION OF CATUNAREGAM SPINOSA (THUMB.) TIRVENG FOR ANTIOXIDANT ACTIVITY

Catunaregam spinosa (Thumb.) Tirveng have been reported in studies to possess antioxidant property. Therefore, present study was undertaken to validate different extracts of C. spinosa for antioxidant activity along with safety margin, according to OECD guidelines for toxicity. The extracts of different solvents, such as, distilled water, ethanol, methanol, acetone, chloroform; petroleum ether and benzene were subjected to phytochemical screening and characterization was done by using UV-Visible spectrophotometer. The toxicity studies displayed considerable margin of safety and no adverse effects observed upto 2gm/kg of administration of extract. The antioxidant property of extract of C. spinosa was evaluated for DPPH and FRAP activity. The IC50 value for DPPH activity was found to be 85% and the FRAP was found to be 2.5 μg/ml. These results when compared to standard values indicate towards superior antioxidant potential of C. spinosa extract

Thermal conductivity of epitaxially grown InP : experiment and simulation

Altres ajuts: Catalan AGAURThe integration of III-V optoelectronic devices on silicon is confronted with the challenge of heat dissipation for reliable and stable operation. A thorough understanding and characterization of thermal transport is paramount for improved designs of, for example, viable III-V light sources on silicon. In this work, the thermal conductivity of heteroepitaxial laterally overgrown InP layers on silicon is experimentally investigated using microRaman thermometry. By examining InP mesa-like structures grown from trenches defined by a SiO mask, we found that the thermal conductivity decreases by about one third, compared to the bulk thermal conductivity of InP, with decreasing width from 400 to 250 nm. The high thermal conductivity of InP grown from 400 nm trenches was attributed to the lower defect density as the InP microcrystal becomes thicker. In this case, the thermal transport is dominated by phonon-phonon interactions as in a low defect-density monocrystalline bulk material, whereas for thinner InP layers grown from narrower trenches, the heat transfer is dominated by phonon scattering at the extended defects and InP/SiO interface. In addition to the nominally undoped sample, sulfur-doped (1 × 10 cm) InP grown on Si was also studied. For the narrower doped InP microcrystals, the thermal conductivity decreased by a factor of two compared to the bulk value. Sources of errors in the thermal conductivity measurements are discussed. The experimental temperature rise was successfully simulated by the heat diffusion equation using the FEM

Anti-Inflammatory, Analgesic and Antipyretic Activity of Catunaregam spinosa (Thumb.) Tirveng Extracts

Catunaregam spinosa leaves have been ethnopharmacologically accounted for acquiring various pharmacological properties. The present study was undertaken to evaluate anti-inflammatory, analgesic and antipyretic potential of leaves of C. spinosa.The ethanolic extract was selected for this purpose based on phytochemical screening. Inflammation was inhibited at the dose of 200 mg/kg with percent inhibition of inflammation 32.06, 37.28 and 43.16 %, respectively, at 1, 3 and 5 h, while in egg albumin model % inhibition was found to be 47.81%. There was no significant analgesic activity seen in acetic acid induced writhing response method while significant effects were observed in the doses of 25 and 100 mg/kg on hot plate test. No antipyretic activity was shown by ethanolic extracts(25, 100 and 200 mg/kg) against Brewer’s yeast induced pyrexia in rats. Keywords: Catunaregam spinosa, Anti-inflammatory activity, Phytochemical screening, Ethanolic extract

High Quality III-V Semiconductors/Si Heterostructures for Photonic Integration and Photovoltaic Applications

This thesis deals with one of the promising strategies to monolithically integrate III-V semiconductors with silicon via epitaxial lateral overgrowth (ELOG) technology and is supported by extensive experimental results. The aimed applications are light sources on silicon for electronics-photonics integration and cost effective high efficiency multijunction solar cells. The work focusses on the growth of III-V semiconductors consisting of indium phosphide (InP) and its related alloys on silicon primarily because of the bandgaps that these offer for the aimed applications. For this purpose, we make use of the epitaxial growth technique called hydride vapour phase epitaxy and exploit its near equilibrium operation capability to achieve primarily ELOG of high quality InP as the starting material on patterned InP(seed)/silicon wafer. The InP/InGaAsP layers are grown by metal organic vapour phase epitaxy. Different pattern designs are investigated to achieve high quality InP over a large area of silicon by ELOG to realise lasers. First, nano patterns designed to take advantage of aspect ratio trapping of defects are investigated. Despite substantial defect filtering insufficient growth area is achieved. To achieve a larger area, coalescence from multiple nano openings is used. Shallowly etched InP/InGaAsP based microdisk resonators fabricated on indium phosphide on silicon achieved by this method have shown whispering gallery modes. However, no lasing action is observed partly due to the formation of new defects at the points of coalescence and partly due to leakage losses due to shallow etching. To overcome these limitations, a new design mimicking the futuristic monolithic evanescently coupled laser design supporting an efficient mode coupling and athermal operation is adopted to yield large areas of ELOG InP/Si having good carrier transport and optical properties. Microdisk resonators fabricated from the uniformly obtained InP/InGaAsP structures on the ELOG InP layers have shown very strong spontaneous luminescence close to lasing action. This is observed for the first time in InP/InGaAsP laser structures grown on ELOG InP on silicon. A newly modified ELOG approach called Corrugated ELOG is also developed. Transmission electron microscopy analyses show the formation of abrupt interface between InP and silicon. Electrical measurements have supported the linear Ohmic behaviour of the above junction. This proof of concept can be applied to even other III-V compound solar cells on silicon. This allows only thin layers of expensive III-V semiconductors and cheap silicon as separate subcells for fabricating next generation multijunction solar cells with enhanced efficiencies at low cost. A feasible device structure of such a solar cell is presented. The generic nature of this technique also makes it suitable for integration of III-V light sources with silicon and one such design is proposed.  QC 20141010</p

High Quality III-V Semiconductors/Si Heterostructures for Photonic Integration and Photovoltaic Applications

This thesis deals with one of the promising strategies to monolithically integrate III-V semiconductors with silicon via epitaxial lateral overgrowth (ELOG) technology and is supported by extensive experimental results. The aimed applications are light sources on silicon for electronics-photonics integration and cost effective high efficiency multijunction solar cells. The work focusses on the growth of III-V semiconductors consisting of indium phosphide (InP) and its related alloys on silicon primarily because of the bandgaps that these offer for the aimed applications. For this purpose, we make use of the epitaxial growth technique called hydride vapour phase epitaxy and exploit its near equilibrium operation capability to achieve primarily ELOG of high quality InP as the starting material on patterned InP(seed)/silicon wafer. The InP/InGaAsP layers are grown by metal organic vapour phase epitaxy. Different pattern designs are investigated to achieve high quality InP over a large area of silicon by ELOG to realise lasers. First, nano patterns designed to take advantage of aspect ratio trapping of defects are investigated. Despite substantial defect filtering insufficient growth area is achieved. To achieve a larger area, coalescence from multiple nano openings is used. Shallowly etched InP/InGaAsP based microdisk resonators fabricated on indium phosphide on silicon achieved by this method have shown whispering gallery modes. However, no lasing action is observed partly due to the formation of new defects at the points of coalescence and partly due to leakage losses due to shallow etching. To overcome these limitations, a new design mimicking the futuristic monolithic evanescently coupled laser design supporting an efficient mode coupling and athermal operation is adopted to yield large areas of ELOG InP/Si having good carrier transport and optical properties. Microdisk resonators fabricated from the uniformly obtained InP/InGaAsP structures on the ELOG InP layers have shown very strong spontaneous luminescence close to lasing action. This is observed for the first time in InP/InGaAsP laser structures grown on ELOG InP on silicon. A newly modified ELOG approach called Corrugated ELOG is also developed. Transmission electron microscopy analyses show the formation of abrupt interface between InP and silicon. Electrical measurements have supported the linear Ohmic behaviour of the above junction. This proof of concept can be applied to even other III-V compound solar cells on silicon. This allows only thin layers of expensive III-V semiconductors and cheap silicon as separate subcells for fabricating next generation multijunction solar cells with enhanced efficiencies at low cost. A feasible device structure of such a solar cell is presented. The generic nature of this technique also makes it suitable for integration of III-V light sources with silicon and one such design is proposed.  QC 20141010</p

Rapidly progressive hip disease masquerading as Gorham′s syndrome of the femoral head

Rapidly destructive hip disease (RDHD) is a rare syndrome of unknown etiology, resulting in rapid deterioration of both the femoral and acetabular aspects of the hip joint with disappearance of the femoral head. Differential diagnosis should include those conditions known to potentially lead to rapid hip destruction, such as septic arthritis, metabolic bone diseases, autoimmune inflammatory arthritis, malignancy, and classical osteonecrosis. Sequential X-rays in patients with fast worsening of hip symptoms and a high degree of clinical suspicion seem mandatory to avoid extensive joint destruction and facilitate better arthroplasty outcomes in these patients. Because of the degree of joint deformity and the patient′s level of disability, the typical treatment of rapidly destructive arthropathy is total hip arthroplasty. In this report, we present a clinical case of left RDHD offering a useful review for the diagnosis and management of this condition

Delayed Repair of Infected Ruptured Patellar Tendon using Suture Anchors

Patellar tendon rupture are rare injuries that are easily missed in acute phases if careful clinical examination is not carried out. The delayed condition is further difficult to treat and augmentation of end to end repair is generally required. However, literature presents no such case of delayed presentation with presence of infection. We here present one such case of delayed presentation of patellar tendon rupture at three weeks in a 52-year-old male patient. Usual techniques were not sufficient to allow early rehabilitation. Technique of suture anchors was planned for repair after thorough debridement. After this intervention, patient was put on aggressive rehabilitation protocol and he gained excellent range of motion. Patient was followed for one year and he showed no loss of movement or signs of infection. We thus recommend using anchor suture repair of patellar tendon that provides a stable and rigid fixation with possibility of early active rehabilitation even in delayed setting

Acute Compressive Ulnar Neuropathy in a Patient of Dengue Fever: An Unusual Presentation

Introduction: Dengue haemorrhagic fever is known for its haemorrhagic and neurologic complications. Neurologic complications are caused by three mechanism namely neurotropism, systemic complications causing encephalopathy and postinfectious immune-mediated mechanisms. However acute compressive neuropathy due to haemorrhage is not frequent and we could find no literature describing this Case Report: We report a case of acute compressive ulnar neuropathy due to peri neural hematoma, following an attempt at intravenous cannulation in the cubital fossa in a patient of dengue haemorrhagic fever with thrombocytopenia. Immediate fasciotomy and removal of haematoma was performed to relieve the symptoms. Conclusion: Compression neuropathies can be seen in dengue hemorrhagic fever and removal of compressing hematoma relieves symptoms. Keywords: Dengue haemmorrhagic fever; coagulopathy; peri neural haematoma

Impact of the 2019 Coronavirus Infectious Disease (COVID-19) pandemic on onset to door time and admissions of new onset acute ischemic stroke in a tertiary care level hospital in North India

Context: Coronavirus infectious disease (COVID-19) pandemic disrupted the already marginalized healthcare provision in resource limited countries like India. Aims: This study compared onset to door time and temporal trends of admissions to seek medical care in new onset acute ischaemic stroke during the COVID-19 period with a representative pre-COVID-19 period in rural background. Settings and Design: Prospective Cross-sectional study in a tertiary level hospital in North India. Methods and Material: Study included new onset acute ischaemic stroke admitted within first 2 weeks of symptoms onset. Subjects were divided into: Group A – Pre-COVID-19 stroke, Group B – Non-COVID-19 Stroke, and Group C - Stroke, positive for COVID-19. Detailed epidemiological, clinical profile, onset to door time and temporal trends of admissions were recorded. Statistical Analysis Used: Chi square/Fisher's exact test and Independent Samples T test or Mann–Whitney U test were used for categorical and continuous variables. Results: Onset to door time in new onset acute ischaemic stroke was significantly prolonged by 6 h in COVID-19 period (median (interquartile range), 19 (12–27) h) as compared with pre-COVID-19 period. Admissions of new onset acute ischaemic stroke were significantly less in COVID-19 period. Comorbidities and severity of stroke (mean National Institutes of Health Stroke Scale, 20 ± 4) were more during the COVID-19 period. Incidence and mortality of COVID-19 positive new onset acute ischaemic stroke were 0.95% and 38%. Conclusions: Onset to door time in new onset acute ischaemic stroke was significantly prolonged in COVID-19 as compared with pre-COVID-19 period. The admissions were fewer with more severity and comorbidities in COVID-19 period. COVID-19 positive stroke patients had more severity and mortality as compared with non-COVID-19 stroke