Optical properties in the visible luminescence of SiO2:B2O3:CaO:GdF3 glass scintillators containing CeF3

Park, J. M.,Kim, H. J.,Karki, Sujita,Kaewkhao, J.,Damdee, B.,Kothan, S.,Kaewjaeng, S. 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. No.

<P>CeF3-doped silicaborate-calcium-gadolinium glass scintillators, with the formula 10SiO(2):(55-x)B2O3:10CaO:25GdF(3):xCeF(3), were fabricated by the melt-quenching technique. The doping concentration of the CeF3 was from 0.00 mol% to 0.20 mol%. The optical properties of the CeF3 doped glass scintillators were studied by using various radiation sources. The transition state of the CeF3-doped glass scintillators studied by using the absorption and photo-luminescence spectrum results. The X-ray, photo, proton and laser-induced luminescence spectra were also studied to understand the luminescence mechanism under various conditions. To understand the temperature dependence, the laser-induced luminescence and the decay component of the CeF3-doped glass scintillator were studied while the temperature was varied from 300 K to 10 K. The emission wavelength spectrum showed from 350 nm to 55 nm under various radiation sources. Also the CeF3-doped glass scintillator have one decay component as 34 ns at room temperature.</P>

Optical Properties in the Visible Luminescence of SiO2:B2O3:CaO:GdF3 Glass Scintillators Containing CeF3

J. M. PARK,김홍주,Sujita Karki,J. Kaewkhao,B. Damdee,S. Kothandaraman,S. Kaewjaeng 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.71 No.11

CeF3-doped silicaborate-calcium-gadolinium glass scintillators, with the formula 10SiO2:(55- x)B2O3:10CaO:25GdF3:xCeF3, were fabricated by the melt-quenching technique. The doping concentration of the CeF3 was from 0.00 mol% to 0.20 mol%. The optical properties of the CeF3 doped glass scintillators were studied by using various radiation sources. The transition state of the CeF3- doped glass scintillators studied by using the absorption and photo-luminescence spectrum results. The X-ray, photo, proton and laser-induced luminescence spectra were also studied to understand the luminescence mechanism under various conditions. To understand the temperature dependence, the laser-induced luminescence and the decay component of the CeF3-doped glass scintillator were studied while the temperature was varied from 300 K to 10 K. The emission wavelength spectrum showed from 350 nm to 55 nm under various radiation sources. Also the CeF3-doped glass scintillator have one decay component as 34 ns at room temperature.

Tumor-like Presentation of Tubercular Brain Abscess: Case Report

Karki, Dan B.,Gurung, Ghanashyam,Sharma, Mohan R.,Shrestha, Ram K.,Sayami, Gita,Sedain, Gopal,Shrestha, Amina,Ghimire, Ram K. Korean Society of Magnetic Resonance in Medicine 2015 Investigative Magnetic Resonance Imaging Vol.19 No.4

A 17-year-old girl presented with complaints of headache and decreasing vision of one month's duration, without any history of fever, weight loss, or any evidence of an immuno-compromised state. Her neurological examination was normal, except for papilledema. Laboratory investigations were within normal limits, except for a slightly increased Erythrocyte Sedimentation Rate (ESR). Non-contrast computerized tomography of her head revealed complex mass in left frontal lobe with a concentric, slightly hyperdense, thickened wall, and moderate perilesional edema with mass effect. Differential diagnoses considered in this case were pilocytic astrocytoma, metastasis and abscess. Magnetic resonance imaging (MRI) obtained in 3.0 Tesla (3.0T) scanner revealed a lobulated outline cystic mass in the left frontal lobe with two concentric layers of T2 hypointense wall, with T2 hyperintensity between the concentric ring. Moderate perilesional edema and mass effect were seen. Post gadolinium study showed a markedly enhancing irregular wall with some enhancing nodular solid component. No restricted diffusion was seen in this mass in diffusion weighted imaging (DWI). Magnetic resonance spectroscopy (MRS) showed increased lactate and lipid peaks in the central part of this mass, although some areas at the wall and perilesional T2 hyperintensity showed an increased choline peak without significant decrease in N-acetylaspartate (NAA) level. Arterial spin labelling (ASL) and dynamic susceptibility contrast (DSC) enhanced perfusion study showed decrease in relative cerebral blood volume at this region. These features in MRI were suggestive of brain abscess. The patient underwent craniotomy with excision of a grayish nodular lesion. Abundant acid fast bacilli (AFB) in acid fast staining, and epithelioid cell granulomas, caseation necrosis and Langhans giant cells in histopathology, were conclusive of tubercular abscess. Tubercular brain abscess is a rare manifestation that simulates malignancy and cause diagnostic dilemma. MRI along with MRS and magnetic resonance perfusion studies, are powerful tools to differentiate lesions in such equivocal cases.

Tumor-like Presentation of Tubercular Brain Abscess: Case Report

Dan B. Karki,Ghanashyam Gurung,Mohan R. Sharma,Ram K. Shrestha,Gita Sayami,Gopal Sedain,Amina Shrestha,Ram K. Ghimire 대한자기공명의과학회 2015 Investigative Magnetic Resonance Imaging Vol.19 No.4

A 17-year-old girl presented with complaints of headache and decreasing vision ofone month’s duration, without any history of fever, weight loss, or any evidence ofan immuno-compromised state. Her neurological examination was normal, exceptfor papilledema. Laboratory investigations were within normal limits, except for aslightly increased Erythrocyte Sedimentation Rate (ESR). Non-contrast computerizedtomography of her head revealed complex mass in left frontal lobe with a concentric,slightly hyperdense, thickened wall, and moderate perilesional edema with masseffect. Differential diagnoses considered in this case were pilocytic astrocytoma,metastasis and abscess. Magnetic resonance imaging (MRI) obtained in 3.0 Tesla(3.0T) scanner revealed a lobulated outline cystic mass in the left frontal lobe withtwo concentric layers of T2 hypointense wall, with T2 hyperintensity between theconcentric ring. Moderate perilesional edema and mass effect were seen. Postgadolinium study showed a markedly enhancing irregular wall with some enhancingnodular solid component. No restricted diffusion was seen in this mass in diffusionweighted imaging (DWI). Magnetic resonance spectroscopy (MRS) showed increasedlactate and lipid peaks in the central part of this mass, although some areas at thewall and perilesional T2 hyperintensity showed an increased choline peak withoutsignificant decrease in N-acetylaspartate (NAA) level. Arterial spin labelling (ASL) anddynamic susceptibility contrast (DSC) enhanced perfusion study showed decrease inrelative cerebral blood volume at this region. These features in MRI were suggestiveof brain abscess. The patient underwent craniotomy with excision of a grayishnodular lesion. Abundant acid fast bacilli (AFB) in acid fast staining, and epithelioidcell granulomas, caseation necrosis and Langhans giant cells in histopathology, wereconclusive of tubercular abscess. Tubercular brain abscess is a rare manifestationthat simulates malignancy and cause diagnostic dilemma. MRI along with MRS andmagnetic resonance perfusion studies, are powerful tools to differentiate lesions insuch equivocal cases.

Localized electrical energy concentration method for multi-electrode bioimpedance measurement

H. Kwon,H. Wi,B. Karki,E.J. Lee,A. McEwan,E.J. Woo,B. Harrach,J.K. Seo,T.I. Oh 한국산업응용수학회 2012 한국산업응용수학회 학술대회 논문집 Vol.7 No.2

Seasonal PM₁₀ dynamics in Kathmandu Valley

Aryal, R.K.,Lee, B.K.,Karki, R.,Gurung, A.,Kandasamy, J.,Pathak, B.K.,Sharma, S.,Giri, N. Pergamon Press ; Elsevier [distribution] 2008 Atmospheric environment Vol.42 No.37

Data on ambient PM<SUB>10</SUB> levels from six locations in the Kathmandu Valley recorded by means of continuous sampling using low volume air samplers from October 2002 to March 2007 were used to investigate PM<SUB>10</SUB> concentration dynamics in the valley. Monthly average data of the urban areas, which have much higher concentrations than the rural areas, even exceeded the daily standard level of PM<SUB>10</SUB>, in Nepal, 120μmm<SUP>-3</SUP>. Repetitive peaks and troughs each year indicated annual patterns. Monthly average showed seasonal patterns are different between rural area and urban sites. The highest monthly average concentration was observed in February, the end of winter in urban areas where as in rural found in spring, and the lowest concentration was observed in July (monsoon period). The continuous increase in PM<SUB>10</SUB> concentration from December to February in urban areas showed accumulation of PM<SUB>10</SUB> in the ambient air during the wintertime. Rainfall in June and September, during the monsoon period, caused a PM<SUB>10</SUB> concentration decrease, demonstrating that precipitation is effective in removing PM<SUB>10</SUB> from the valley. Cross correlation analyses among the PM<SUB>10</SUB> levels measured simultaneously at the sampling stations showed a poor relationship in winter; however, there were good relationships in the monsoon and post-monsoon seasons. Both the PM<SUB>10</SUB> concentration and the air-mixing environment in the valley were closely associated with the temperature and wind speed.

Bioimpedance spectroscopy tensor probe for anisotropic measurements

Kwon, H.,Wi, H.,Karki, B.,Lee, E. J.,McEwan, A.,Woo, E. J.,Harrach, B.,Seo, J. K.,Oh, T. I. IET 2012 Electronics letters Vol.48 No.20

<P>The tetrapolar electrode configuration used in bioimpedance suffers from negative sensitivity and is confounded by anisotropic tissue such as blood vessels or muscle and nerve fibres. Proposed is a circular array of electrodes to focus current directly underneath the probe and provide anisotropy information. It is shown that an implementation using 16 miniature electrodes is able to outperform the tetrapolar method in sensitivity and impedance estimation. The proposed method can also recover anisotropic conductivity tensors from experiments for the first time.</P>

Trends of Smokeless Tobacco use among Adults (Aged 15-49 Years) in Bangladesh, India and Nepal

Sinha, Dhirendra N,Rizwan, SA,Aryal, Krishna K,Karki, Khem B,Zaman, Mostafa M,Gupta, Prakash C Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15

Background: Smokeless tobacco (SLT) has long been realized as an important component of the fight for global tobacco control. It still remains a major problem in countries like India, Bangladesh and Nepal. The objective of this study was to estimate the trends of SLT use in three countries of the SEARO WHO office. Materials and Methods: We used data from national surveys in three countries (Bangladesh, India and Nepal) to estimate trends in prevalence of current SLT use. All available nationally representative data sources were used. Estimates were weighted, age standardized and given along with 95% confidence intervals. Significance of linear trend in prevalence over time was tested using the Cochrane-Armitage test for trend. A p value of less than 0.05 was considered statistically significant. Results: We identified three surveys for Bangladesh, three for India and four for Nepal that met the selection criteria (such as Demographic and Health Surveys, WHO-STEPwise approach to Surveillance and Global Adult Tobacco Surveys). A significantly increasing trend was noticed in the prevalence of current SLT use among Bangladeshi men (20.2% to 23%, p=0.03). In India, a similar significantly increasing trend was seen among men (27.1% to 33.4%, p<0.001) and women (10.1% to 15.7%, p<0.001). In Nepal, there was a no significant trend among both men (39.1% to 31.6%, p=0.11) and women (5.6% to 4.7%, p=0.49). Conclusions: In the study countries SLT use has remained at alarmingly high levels. Usage trends do not show any signs of decline in spite of control efforts. Tobacco control measures should focus more on controlling SLT use.