13 research outputs found

    Growth, photoluminescence, lifetime, and laser damage threshold studies of 1, 3, 5-triphenylbenzene (TPB) single crystal for scintillation application

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    The 1, 3, 5-triphenylbenzene (TPB) single crystal has been grown using slow cooling seed rotation technique. Optical transmittance of the grown crystal was obtained from UV-Visible analysis. The grown TPB crystal has good transmission in the entire visible region with a lower cutoff wavelength of 330 nm. The solubility of TPB material was determined using toluene as a solvent with different temperatures. The full width at half maximum is 18 arcsec, which indicates that the crystal is of good quality. The TPB crystal was excited (lambda (exc)) at 307 nm, and the corresponding emission (lambda (em)) has been observed at 352 nm. The laser-induced damage threshold (LDT) value of grown crystal is 1.25 GW/cm(2). Third-order nonlinear optical susceptibility chi (3) is determined using the Z-scan technique as 3.07422x10(-09) esu. The TPB crystal proves its suitability for scintillation applications and optoelectronic device fabrications

    Influence of growth temperature on structural and optical properties of laser MBE grown epitaxial thin GaN films on a-plane sapphire

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    Epitaxial thin GaN films (similar to 60 nm) have been grown on a-plane sapphire substrates at different growth temperatures (500-700 degrees C) using laser molecular beam epitaxy (LMBE). The effect of growth temperatures on the structural and optical properties of GaN layers grown on low temperature (LT) GaN buffer on prenitridated a-sapphire have been studied systematically. The in situ reflection high energy electron diffraction pattern revealed the three-dimensional epitaxial growth of GaN films on a-sapphire under the adopted growth conditions. The full width at half maximum (FWHM) value of x-ray rocking curves (XRCs) along GaN (0002) and (10-12) planes decreases with increasing growth temperature. The FWHM values of (0002) and (10-12) XRC for the 700 degrees C grown GaN film are 1.09 degrees and 1.08 degrees, respectively. Atomic force microscopy characterization showed that the grain size of GaN increases from 30-60 to 70-125 nm with the increase in growth temperature as GaN coalescence time is shorter at high temperature. The refractive index value for the dense GaN film grown at 600 degrees C is obtained to be similar to 2.19 at the wavelength of 632 nm as deduced by spectroscopic ellipsometry. Photoluminescence spectroscopy confirmed that the epitaxial GaN layers grown on a-sapphire at 600-700 degrees C possess near band edge emission at similar to 3.39 eV, close to bulk GaN. The GaN growth at 700 degrees C without a buffer still produced films with better crystalline and optical properties, but their surface morphology and coverage were inferior to those of the films grown with LT buffer. The results show that the growth temperature strongly influences the structural and optical quality of LMBE grown epitaxial GaN thin films on a-plane sapphire, and a growth temperature of >600 degrees C is necessary to achieve good quality GaN films. Published by the AVS

    Crystalline perfection, EPR, prism coupler and UV-VIS-NIR studies on Cz-grown Fe-doped LiNbO3: A photorefractive nonlinear optical crystal

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    The Fe-doped (0.05 mol%) lithium niobate (LiNbO3) bulk single crystal was gown by the Czochralski (Cz) method using a co-axial two zone low thermal gradient furnace. The crystalline perfection of the grown crystal was evaluated by high resolution X-ray diffractometry which showed that it does not contain any structural grain boundaries, and the dopants predominantly occupied vacancy sites of Li+ in the lattice. Electron paramagnetic resonance studies revealed the incorporation of Fe3+ ions at Li sites. The Z-cut optically polished 450 ÎŒm thick wafer was used for birefringence measurements on a prism coupler spectrometer with 632.8 nm wavelength and it was found that the difference in refractive index (Δn) for ordinary and extraordinary rays is 0.0833. The optical transmission/absorption spectra were studied by UV-VIS-NIR spectroscopy and this showed that the grown crystal has good optical sensitivity for 482 nm wavelength radiation. The present studies reveal that the crystal grown with a two zone low thermal gradient furnace has very good device properties which are needed for holographic data storage applications

    Page kidney following renal allograft biopsy - Early recognition and treatment

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    Ultrasound- guided percutaneous allograft renal biopsy is commonly done to evaluate graft dysfunction. Complications of renal biopsy are usually minor, and major complications occur only in less than 1% cases. We report a case of allograft renal biopsy which caused a subcapsular hematoma, Page kidney and deterioration of graft function. This was diagnosed by computed tomography (CT) scan, and early surgical intervention led to complete recovery

    Analysis of results of primary closure in fistula in ANO

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    Aim: Prospective analysis of results of primary closure in fistula in ano in terms of (a) Immediate- Bleeding, perianal haematoma, pain, suture line dehiscence and healingperiod. (b) Later - Incontinence & reccurence rate and Patient’s compliance & feasibility of technique in NSCBMC Jabalpur. Methods: Prospective study was conducted in Department of Surgery, NSCB Medical College, Jabalpurbetween Aug. 2012 to Sept. 2013. Total 60 patients were taken and divided in two groups, group-A (30 patients) taken as case study in which pimary closure was done and group-B (30 patients) taken as control group in which open fistulectomy was done. Results:  Majority of patients were 31 to 60 years (80%). More number of males than females. (M=93.3%, F=6.7%). Perianal Discharge (90%), Pain (56.7%) and Swelling (33.3%) were the main complaints. Fistula-in-ano with a single opening (83.3%) was the commonest occurrence and posterior opening (70%) situation was more common. Bleeding was seen in open method (group-B=30%) whereas none of the patients shows bleeding in primary closure technique (group-A). Perianal haematoma was more seen in open method (group-B=20%) compare to primary closure method (group-A=6.6%)

    Concomitant laparoscopic urological procedures: Does it contribute to morbidity?

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    Aim: With advancement in minimal access surgery two laparoscopic procedures can be combined together shortening the total hospital stay, decreasing morbidity and overall reduced cost. Combining two laparoscopic procedures in a single session has been reported in general surgery. Very few articles are available in literature with regard to combined urological laparoscopic surgeries. This article retrospectively analyses the outcomes of multiple laparoscopic procedures performed in a single stage at our centre. Materials and Methods: Patients undergoing simultaneous procedures from May 2003 to Jan 2009 were included in the study. Patients were categorised into three groups according to the primary urological organ involved, for better comparison with the control group. Diseases involving the adrenals gland were grouped in (group 1), kidney (group 2) and renal collecting system/ureter (group 3). All patients had one urological procedure for either of the above-mentioned organs combined with another surgical procedure. Similarly three control groups were chosen according to the primary urological organ involved (group 1c- unilateral laparoscopic adrenalectomy, group 2c- unilateral laparoscopic radical nephrectomy and group 3c- unilateral laparoscopic ureterolithotomy) for comparative study. The operative details, hospital stay and complications were analysed. Results: Thirty-two patients underwent 64 laparoscopic procedures under single anaesthesia. The most common procedure in this series was laparoscopic adrenalectomy (n=34) followed by laparoscopic nephrectomy (n=13). Group 1 patients had a prolonged operative time ( P=0.012) and hospital stay ( P=0.025) when compared with group 1c. However, blood loss was comparable in both the groups. Patients in groups 2 and 3 had comparable operative times, blood loss and recovery period with respect to their controls. Intraoperatively, the end tidal carbon dioxide levels were within permissible limits. All procedures were completed using the laparoscopic approach, without any conversion. Conclusions: Simultaneous laparoscopic procedures can be done for urological diseases in selected patients with the advantages of single anaesthesia and hospital admission without increasing the morbidity

    Concomitant laparoscopic urological procedures: Does it contribute to morbidity?

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    Aim: With advancement in minimal access surgery two laparoscopic procedures can be combined together shortening the total hospital stay, decreasing morbidity and overall reduced cost. Combining two laparoscopic procedures in a single session has been reported in general surgery. Very few articles are available in literature with regard to combined urological laparoscopic surgeries. This article retrospectively analyses the outcomes of multiple laparoscopic procedures performed in a single stage at our centre. Materials and Methods: Patients undergoing simultaneous procedures from May 2003 to Jan 2009 were included in the study. Patients were categorised into three groups according to the primary urological organ involved, for better comparison with the control group. Diseases involving the adrenals gland were grouped in (group 1), kidney (group 2) and renal collecting system/ureter (group 3). All patients had one urological procedure for either of the above-mentioned organs combined with another surgical procedure. Similarly three control groups were chosen according to the primary urological organ involved (group 1c- unilateral laparoscopic adrenalectomy, group 2c- unilateral laparoscopic radical nephrectomy and group 3c- unilateral laparoscopic ureterolithotomy) for comparative study. The operative details, hospital stay and complications were analysed. Results: Thirty-two patients underwent 64 laparoscopic procedures under single anaesthesia. The most common procedure in this series was laparoscopic adrenalectomy (n=34) followed by laparoscopic nephrectomy (n=13). Group 1 patients had a prolonged operative time ( P=0.012) and hospital stay ( P=0.025) when compared with group 1c. However, blood loss was comparable in both the groups. Patients in groups 2 and 3 had comparable operative times, blood loss and recovery period with respect to their controls. Intraoperatively, the end tidal carbon dioxide levels were within permissible limits. All procedures were completed using the laparoscopic approach, without any conversion. Conclusions: Simultaneous laparoscopic procedures can be done for urological diseases in selected patients with the advantages of single anaesthesia and hospital admission without increasing the morbidity

    Occurrence, Impact on Agriculture, Human Health, and Management Strategies of Zearalenone in Food and Feed: A Review

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    Mycotoxins represent an assorted range of secondary fungal metabolites that extensively occur in numerous food and feed ingredients at any stage during pre- and post-harvest conditions. Zearalenone (ZEN), a mycotoxin categorized as a xenoestrogen poses structural similarity with natural estrogens that enables its binding to the estrogen receptors leading to hormonal misbalance and numerous reproductive diseases. ZEN is mainly found in crops belonging to temperate regions, primarily in maize and other cereal crops that form an important part of various food and feed. Because of the significant adverse effects of ZEN on both human and animal, there is an alarming need for effective detection, mitigation, and management strategies to assure food and feed safety and security. The present review tends to provide an updated overview of the different sources, occurrence and biosynthetic mechanisms of ZEN in various food and feed. It also provides insight to its harmful effects on human health and agriculture along with its effective detection, management, and control strategies

    Clinicoradiological Features and Treatment Outcome of Supratentorial Intraparenchymal Epidermoid Cyst: A Report of Five Cases and Literature Review

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    Objectives Intraparenchymal epidermoid cysts (IECs) are rare lesions. They represent less than 1% of the intracranial epidermoid cysts. The supratentorial IEC is a clinically and prognostically distinct subset. Given the rarity, most of the articles are case reports. We present a series of five cases of supratentorial IEC to characterize their clinical presentation and outcome, with emphasis on the surgical features. Materials and Methods We searched our database for all cases of intracranial epidermoid cysts operated between January 2005 and January 2020. Five patients were identified having IEC from the hospital information system and the neurosurgical operation record book. Standard craniotomy and decompression of the lesion were performed in all these patients. Standard postoperative care includes computed tomography scan of head on the day of surgery and magnetic resonance imaging of brain after 6 weeks to look for the residual lesion, if any. Subsequent follow-up visits in outpatient department to look for resolution of the presurgical symptoms. Results The mean age of the patients in our series was 28.8 years (range: 28–40 years.). All the five patients were male. Four patients had IEC involving frontal lobe and one in parietal lobe with a small occipital lobe extension. Seizure was the most common presenting complaint followed by headache. Complete excision was achieved in all the cases. All the three patients with seizure attained seizure freedom postlesionectomy. Focal neurological deficits resolved gradually in postoperative period. There was no recurrence of lesion during follow-up. Conclusion Supratentorial IEC most commonly affects young males, involve frontal lobe and present clinically with seizure. Complete surgical excision offers best outcome in the form of remission of seizure disorder
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