10 research outputs found

    Structural, optical and electronic properties of homoepitaxial GaN nanowalls grown on GaN template by laser molecular beam epitaxy

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    We have grown homoepitaxial GaN nanowall networks on GaN template using an ultra-high vacuum laser assisted molecular beam epitaxy system by ablating solid GaN target under a constant r.f. nitrogen plasma ambient. The effect of laser repetition rate in the range of 10 to 30 Hz on the structural properties of the GaN nanostructures has been studied using high resolution X-ray diffraction, field emission scanning electron microscopy and Raman spectroscopy. The variation of the laser repetition rate affected the tip width and pore size of the nanowall networks. The z-profile Raman spectroscopy measurements revealed the GaN nanowall network retained the same strain present in the GaN template. The optical properties of these GaN nanowall networks have been studied using photoluminescence and ultrafast spectroscopy and an enhancement of optical band gap has been observed for the nanowalls having a tip width of 10-15 nm due to the quantum carrier confinement effect at the wall edges. The electronic structure of the GaN nanowall networks has been studied using X-ray photoemission spectroscopy and it has been compared to the GaN template. The calculated Ga/N ratio is largest (similar to 2) for the GaN nanowall network grown at 30 Hz. Surface band bending decreases for the nanowall network with the lowest tip width. The homoepitaxial growth of porous GaN nanowall networks holds promise for the design of nitride based sensor devices

    Un cas etrange de la fistule cervicocutanee

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    A lady presented with 6 months of amenorrhea and cyclical menstruation through an opening in the abdominal wall for the same duration, following septic abortion. Examination and investigations revealed an extraperitoneal Cervicocutaneous fistula, which was excised in toto. She had an uneventful recovery and resumed normal periods (Afr J Reprod Health 2010; 14[1]:135-137).Une dame a prĂ©sentĂ© une amĂ©norrhĂ©e qui a durĂ© six mois et d’une menstruation cyclique Ă  travers une ouverture dans le paroi abdominale pour la mĂȘme durĂ©e, suite Ă  un avortement septique. L’examen et les Ă©tudes ont rĂ©vĂ©lĂ© une fistule cervicocutanĂ©e extrapĂ©ritonĂ©ale qui a Ă©tĂ© excisĂ©e totalement. Sa rĂ©cupĂ©ration fut sans incidents et elle a repris ses rĂšgles normales (Afr J Reprod Health 2010; 14[1]:135-137)

    Comparison of ‘push method’ with ‘Patwardhan’s method’ on maternal and perinatal outcomes in women undergoing caesarean section in second stage

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    A deeply impacted foetal head in a second stage caesarean section is associated with an increased risk of maternal and neonatal complications. For the present study, we compared the maternal and neonatal outcomes during the use of the ‘Push method’ and of ‘Patwardhan’s method’ for a foetal head delivery in a second-stage caesarean section. This was a retrospective observational study involving 298 women who underwent a second stage caesarean section with a foetal head at or below the level of their ischial spines and was conducted in a tertiary teaching hospital in South India. The rates of uterine incision extension and other maternal complications were similar in both methods (24.9% vs. 26.0%, p = .850). The rates of neonatal sepsis (2.3% vs. 9.2%) and admission to neonatal intensive care unit (36.7% vs. 60.0%) were higher when Patwardhan’s method was used. Although the maternal complications were similar, the use of Patwardhan’s method resulted in higher rates of neonatal complications compared to the Push method during a second stage caesarean section. Future randomised, controlled studies comparing these two methods are needed to confirm their safety and benefits, prior to its routine use in second stage caesarean sections.Impact statement What is already known on this subject? Use of a second-stage caesarean section increases the risk of maternal and neonatal complications. A deeply engaged foetal head, along with the stretching and thinning of the lower uterine segment predisposes to these complications. The recent literature mainly compares the complication rates of the Push method to a Reverse breech extraction, with only small studies reporting the use of Patwardhan’s technique for the delivery of a deeply engaged foetal head. What do the results of this study add? This study suggests that the use of either the Push method or of Patwardhan’s method results in similar maternal complications such as extension of a uterine incision or postpartum haemorrhage. But neonatal complications such as neonatal sepsis (2.3% vs. 9.2%) and admission to neonatal intensive care unit (36.7% vs. 60.0%) were higher when Patwardhan’s method was used. What are the implications of these findings for clinical practice and/or further research? The extension of uterine incision is similar in both methods; however, the neonatal complications were noted to be higher in those delivered with Patwardhan’s technique. A future, randomised controlled trial comparing these two techniques is required to confirm the findings, before either of the methods are used in routine practice

    The impact of RF-plasma power in carrier relaxation dynamics of unintentional doped GaN epitaxial layers grown by MBE

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    In this work, unintentionally doped GaN samples were prepared on GaN template by radio frequency (RF)-plasma MBE technique using two different RF-plasma powers. Photoluminescence (PL), steady state photoconductivity (PC) and ultrafast optical pump-probe spectroscopy measurements have been carried out to characterize the samples. The effect of RF-plasma power towards unintentional doping and giving rise to yellow luminescence (YL) is discussed. Our PC measurements show relatively faster decay for sample grown with higher RF-plasma power. In addition, the ultrafast optical pump-probe spectroscopy results show the presence of various defect levels with different relaxation times. A faster ultrafast relaxation time from the conduction band to the closest defect level and conduction band to the next defect level was observed for the sample grown with higher plasma power A comparatively low defect density and faster carrier relaxation observed in higher RF-plasma power grown samples is caused by lower impurities and gallium vacancies. The results imply that RF-plasma power is very important parameter for the growth of epitaxial GaN films and undesirable impurities and gallium vacancies might get incorporated in the epitaxial GaN films

    Prophylactic magnesium sulphate in prevention of eclampsia in women with severe preeclampsia: randomised controlled trial (PIPES trial)

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    Optimum dose, route and duration of use of prophylactic magnesium sulphate in women with severe pre-eclampsia is still controversial. We compared the efficacy and safety of ‘low-dose Dhaka’ regime with ‘Loading dose only’ regime for seizure prophylaxis in severe preeclampsia using a randomised controlled trial in 402 women. The incidence of eclampsia in the ‘low-dose Dhaka’ regime group was 1.49% and that in the ‘Loading dose only regime’ was 2.98% (p = .321). In the low-dose Dhaka regime, injection site abscess and respiratory depression occurred in one woman each. Neonatal outcomes such as Apgar score at 5 minutes (5.0% vs. 8.05% p = .251) and perinatal mortality (20.4% vs. 21.9%, p = .724) were similar in both groups. Loading dose only regime may be considered an effective alternative regime for the prevention of eclampsia in women with severe preeclampsia.Impact statement What is already known on this subject: Efficacy of therapeutic short regime magnesium sulphate in eclampsia has already been reported. Data regarding prophylactic short regime in women with preeclampsia is sparse. What the results of this study add: We have shown that short regime of magnesium sulphate using only the loading dose in the prevention of seizure in preeclampsia is an effective alternative to the low-dose Dhaka regime. What the implications are of these findings for clinical practice and/or further research: The short regime is less resource-intensive. Further larger studies are needed to confirm the efficacy of this short regime and to establish its cost-effectiveness

    Abstracts of International Conference on Innovations in Business Management

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    This book contains abstracts of the various research ideas of the academic community and practitioners of management presented at the International Conference on Innovations in Business Management (ICIBM 2020). The researchers have contributed toward various themes of the conference such as sustainable economy, supply chain, women-empowerment, export-import, microfinance, government policies, etc. We strongly believe that it will open up further scope for in-depth research in various disciplines of business management. Best wishes to the participants to have detailed discussions on the above-said wide range of areas. Conference Title: International Conference on Innovations in Business ManagementConference Acronym: ICIBM 2020Conference Date: 16-17 January 2020Conference Location: ICFAI University, Dehradun, IndiaConference Organizers: ICFAI Business School, ICFAI University, Dehradun, India & University of Derby, United Kingdo

    Graphene-based nanocomposites for sensitivity enhancement of surface plasmon resonance sensor for biological and chemical sensing: A review

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