166 research outputs found

    Xe Irradiation of Graphene on Ir(111): From Trapping to Blistering

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    Using X-ray photoelectron spectroscopy, thermal desorption spectroscopy, and scanning tunneling microscopy we show that upon keV Xe + irradiation of graphene on Ir(111), Xe atoms are trapped under the graphene. Upon annealing, aggregation of Xe leads to graphene bulges and blisters. The efficient trapping is an unexpected and remarkable phenomenon, given the absence of chemical binding of Xe to Ir and to graphene, the weak interaction of a perfect graphene layer with Ir(111), as well as the substantial damage to graphene due to irradiation. By combining molecular dynamics simulations and density functional theory calculations with our experiments, we uncover the mechanism of trapping. We describe ways to avoid blister formation during graphene growth, and also demonstrate how ion implantation can be used to intentionally create blisters without introducing damage to the graphene layer. Our approach may provide a pathway to synthesize new materials at a substrate - 2D material interface or to enable confined reactions at high pressures and temperatures

    Aktivitas Ngengat Scirpophaga Incertulas di Wilayah Kabupaten Klaten

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    The activities of Scirpophaga incertulas adult from Klaten Regency were studied from April to November 2010. The purposes of this study were to observe the activity of moth after adult emergence, their flying activity, and eggs oviposition. Two hundred pupae were collected from the field, then incubated in the laboratory and observed every hour for 72 hours. Flying activity was observed every hour by counting the number of moths that were found in the light traps. This observation was replicated three times during the dark; from 6:00 p.m. to 6:00 a.m. Oviposition activity of moths was observed by infesting twenty females of insect on the rice plants planted in the polybag and covered with plastic sheet. This oviposition activity was also observed every hour during the dark; from 6:00 p.m. to 6:00 a.m. in order to get the number of egg-laying moths. The results showed that the emergence of S. incertulas moth was mainly from 2:00 to 4:00 a.m., the flying activity was detected mostly from 6:00 p.m. to 1:00 a.m., and the moths ovipositing activity was mainly occured from 7:00 to 11:00 p.m. In addition, we found that the intensity of light affected the number of moths coming into the light trap. The light exposed from the 23 Watt lamp (1,500 lumen) was twice more effective in attracting the moths than the 11 Watt lamp (700 lumen).Penelitian aktivitas ngengat Scirpophaga incertulas telah dilakukan di Kabupaten Klaten dari April s.d. November 2010. Tujuan penelitian adalah untuk mendapatkan informasi tentang aktivitas kemunculan ngengat, aktivitas terbang dan peletakan telur. Dua ratus pupa yang diperoleh dari lapang diinkubasikan di laboratorium dan diamati sampai muncul ngengat. Jumlah ngengat yang muncul diamati setiap jam selama 72 jam. Aktivitas terbang diamati setiap jam dengan menghitung jumlah ngengat yang terperangkap pada lampu perangkap selama 12 jam dari pukul 18.00 s.d. 06.00 dengan tiga kali ulangan. Aktivitas peletakan telur diamati dengan menginfestasikan dua puluh ngengat betina pada tanaman padi di polibag yang disungkup plastik. Pengamatan aktivitas peletakan telur dilakukan setiap jam dengan mencatat jumlah ngengat yang bertelur selama 12 jam dari pukul 18.00 s.d. 06.00. Hasil pengamatan menunjukkan bahwa kemunculan ngengat S. incertulas paling banyak dijumpai dari pukul 02.00 s.d. 04.00, aktivitas terbang ngengat berlangsung dari pukul 18.00 s.d. 01.00 dan peletakan telur umumnya berlangsung dari pukul 19.00 s.d. 23.00. Kekuatan cahaya lampu perangkap berpengaruh terhadap kedatangan ngengat, cahaya lampu 23 watt (1.500 lumen) lebih banyak menarik kedatangan ngengat dibanding cahaya lampu 11 watt (700 lumen) dengan rasio 2:1

    Pharmacological insights and prediction of lead bioactive isolates of Dita bark through experimental and computer-aided mechanism.

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    Dita bark (Alstonia scholaris (L.) R. Br.) is an ethnomedicine used for the management of various ailments. This study aimed to investigate the biological properties of methanol extract of A. scholaris bark (MEAS), through in vivo, in vitro and in silico approaches alongside its phytochemical profiling. Identification and nature of the bioactive secondary metabolites were studied by the established qualitative tests and GC-MS analysis. The antidepressant activity was determined by forced swimming test (FST) and tail suspension test (TST) in mice. The anti-inflammatory and thrombolytic effect was evaluated using inhibition of protein denaturation technique and clot lysis technique, respectively. Besides, computational studies of the isolated compounds and ADME/T analysis were performed by Schrodinger-Maestro (v11.1) software, and PASS prediction was conducted through PASS online tools. The GC-MS analysis revealed the presence of several secondary metabolites in MEAS. Treatment with MEAS revealed a significant reduction of immobility time in a dose-dependent manner in FST and TST. Besides, MEAS showed substantial anti-inflammatory effects at the higher dose (400 μg/mL) as well as revealed notable clot lysis effect as compared to control. In the case of computer-aided investigation, all compounds meet the condition of Lipinski's rule of five. PASS study also predicted for all compounds, and among these safe compound furazan-3-amine showed the most spontaneous binding energy for both antidepressant and thrombolytic activities, as well as 5-dimethylamino-6 azauracil, found promising for anti-inflammatory activity. Taken together, the investigation concludes that MEAS can be a potent source of antidepressant, anti-inflammatory, and thrombolytic agents

    Pulmonary Tuberculosis and Drug Resistance in Dhaka Central Jail, the Largest Prison in Bangladesh

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    There are limited data on TB among prison inmates in Bangladesh. The aim of the study was to determine the prevalence of pulmonary tuberculosis (TB), its drug resistance and risk factors in Dhaka Central Jail, the largest prison in Bangladesh.Cross sectional survey with, active screening of a total number of 11,001 inmates over a period of 2 years. Sputum samples from TB suspects were taken for acid- fast bacilli (AFB) microscopy, culture and drug susceptibility testing. (5.37, 4.02–7.16).The study results revealed a very high prevalence of TB in the prison population in Dhaka Central Jail. Entry examinations and active symptom screening among inmates are important to control TB transmission inside the prison. Identifying undiagnosed smear-negative TB cases remains a challenge to combat this deadly disease in this difficult setting

    Is metal artefact reduction mandatory in cardiac PET/CT imaging in the presence of pacemaker and implantable cardioverter defibrillator leads?

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    Abstract Purpose Cardiac PET/CT imaging is often performed in patients with pacemakers and implantable cardioverter defibrillator (ICD) leads. However, metallic implants usually produce artefacts on CT images which might propagate to CTbased attenuation-corrected (CTAC) PET images. The impact of metal artefact reduction (MAR) for CTAC of cardiac PET/ CT images in the presence of pacemaker, ICD and ECG leads was investigated using both qualitative and quantitative analysis in phantom and clinical studies. Methods The study included 14 patients with various leads undergoing perfusion and viability examinations using dedicated cardiac PET/CT protocols. The PET data were corrected for attenuation using both artefactual CT images and CT images corrected using the MAR algorithm. The severity and magnitude of metallic artefacts arising from these leads were assessed on both linear attenuation coefficient maps (μ-maps) and attenuation-corrected PET images. CT and PET emission data were obtained using an anthropomorphic thorax phantom and a dedicated heart phantom made in-house incorporating pacemaker and ICD leads attached at the right ventricle of the heart. Volume of interest-based analysis and regression plots were performed for regions related to the lead locations. Bull's eye view analysis was also performed on PET images corrected for attenuation with and without the MAR algorithm. Results In clinical studies, the visual assessment of PET images by experienced physicians and quantitative analysis did not reveal erroneous interpretation of the tracer distribution or significant differences when PET images were corrected for attenuation with and without MAR. In phantom studies, the mean differences between tracer Nucl Med Mol Imaging (2011) 38:252-262 DOI 10.1007/s00259-010-1635 uptake obtained without and with MAR were 10.16±2.1% and 6.86±2.1% in the segments of the heart in the vicinity of metallic ICD or pacemaker leads, and were 4.43±0.5% and 2.98±0.5% in segments far from the leads. Conclusion Although the MAR algorithm was able to effectively improve the quality of μ-maps, its clinical impact on the interpretation of PET images was not significant. Therefore cardiac PET images corrected for attenuation using CTAC in the presence of metallic leads can be interpreted without correction for metal artefacts. It should however be emphasized that in some special cases with multiple ICD leads attached to the myocardium wall, MAR might be useful for accurate attenuation correction. Eur

    Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990–2017:a systematic analysis for the Global Burden of Disease Study 2017

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    Global economic burden of unmet surgical need for appendicitis

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    Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US 92492millionusingapproach1and92 492 million using approach 1 and 73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was 95004millionusingapproach1and95 004 million using approach 1 and 75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially
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