Probing the Shape of a Graphene Nanobubble

Gas molecules trapped between graphene and various substrates in the form of bubbles are observed experimentally. The study of these bubbles is useful in determining the elastic and mechanical properties of graphene, adhesion energy between graphene and substrate, and manipulating the electronic properties via strain engineering. In our numerical simulations, we use a simple description of elastic potential and adhesion energy to show that for small gas bubbles ($\sim 10$ nm) the van der Waals pressure is in the order of 1 GPa. These bubbles show universal shape behavior irrespective of their size, as observed in recent experiments. With our results the shape and volume of the trapped gas can be determined via the vibrational density of states (VDOS) using experimental techniques such as inelastic tunneling and inelastic neutron scattering. The elastic energy distribution in the graphene layer which traps the nanobubble is homogeneous apart from its edge, but the strain depends on the bubble size thus variation in bubble size allows control of the electronic and optical properties.Comment: 5 Figures (Supplementary: 1 Figure), Accepted for publication in PCC

Structural characterization of carbon nanotubes via the vibrational density of states

The electrical and chemical properties of carbon nanotubes vary significantly with different chirality and diameter, making the experimental determination of these structural properties important. Here, we show that the vibrational density of states (VDOS) contains information on the structure of carbon nanotubes, particularly at low frequencies. We show that the diameter and chirality of the nanotubes can be determined from the characteristic low frequency $L$ and $L'$ modes in the VDOS. For zigzag nanotubes, the $L$ peak splits into two peaks giving rise to another low energy $L"$ peak. The significant changes in the frequencies and relative intensities of these peaks open up a route to distinguish among structurally different nanotubes. A close study of different orientations of Stone-Wales defects with varying defect density reveals that different structural defects also leave distinct fingerprints in the VDOS, particularly in the $L$ and $L'$ modes. With our results, more structural information can be obtained from experiments which can directly measure the VDOS, such as inelastic electron and inelastic neutron spectroscopy.Comment: 5 Figures, Accepted for publication in Carbo

Surface modification of thermally evaporated CdTe thin films for sensing application of organic compounds

The study involves the growth of bulk cadmium telluride (CdTe) by using vertical directional solidification (VDS) technique. The as grown CdTe compound has been used as a source material to deposit thin films onto glass substrates at room temperature by thermal evaporation technique under high vacuum conditions of 10-5 mbar. The thickness of film has been measured around 310 nm. Characterization of bulk CdTe compound and its thin films have been done by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM) and photoluminescence (PL) techniques. CdTe thin films have been then used for exposure to vapors of organic compounds such as acetone, formaldehyde, methanol, ethanol, benzene, toluene and chloroform in order to ascertain the use of these films for various sensors. The optical and micro structural properties of CdTe thin films have been studied using PL and AFM techniques so as to evaluate the sensing capabilities of CdTe thin film towards specific compounds which have been used for exposure

Evaluation of peripheral arterial occlusive disease by computed tomography angiography

Background: Characterization of peripheral arterial occlusive disease (PAOD) can be performed with non-invasive angiography using computed tomography (CT). The present study was conducted to evaluate the CT angiographic spectrum of aortoiliac and the lower limb arterial disease in symptomatic patients of peripheral arterial occlusive disease (PAOD) and to classify the lesions according to the Trans-Atlantic Inter-Society Consensus II (TASC II).Methods: The study was carried out in the department of radio-diagnosis in collaboration with departments of cardiothoracic surgery, cardiology and surgery, Safdarjung Hospital and Vardhman Mahavir Medical College, New Delhi. 50 patients aged above 40 years presenting with symptoms and (or) signs of lower limb peripheral arterial disease were recruited into the study after evaluating the renal function. Patient’s clinical history, ABI index and categories of PAOD according to the classification of Fontaine was noted. CT angiography of aortoiliac and lower limb arteries was performed with Philips Brilliance 40 CT unit. The findings in each CT angiography were analysed in respect to site, number, nature and distribution of the lesions and classified individually according to the TASC II.Results: The patients included in the study were all more than 40 years of age. The age range in the study group was 42 years to 75 years. The majority (86%) were male patients. Smoking and dyslipidemia were found to be the main risk factors in our patients. 24% of patients had documentary evidence of ischemic heart disease. On grading with ABI majority of patients (58%) presented in the end stage of the disease (stage IV). On CT angiography, number of lesions detected was 157. 97.4% of lesions were either stenotic or occlusive and 2.54% are with aneurysm. Maximum number of patients had femoropopliteal lesions followed by aortailiac lesions. 14 Winslow pathways were found in 10 patients. Maximum numbers of femoropopliteal lesions (47.29%) belong to type D, type B lesions account for 50% of total aortoiliac lesions based on TASC II classification. Out of 50, 40 were made follow up. Among them 8 were managed with conservative treatment and remaining 32 managed with treatment based TASC II classification.Conclusions: CT angiography is a reliable noninvasive imaging method for the comprehensive and multi parameter evaluation of patients with PAOD. CT angiographic findings are a highly accurate basis for treatment decisions and planning

International Chronic Ocular Graft-vs-Host-Disease (GVHD) Consensus Group: Proposed Diagnostic Criteria for Chronic GVHD (Part I)

The International Chronic Ocular GVHD Consensus Group held 4 working meetings to define new diagnostic metrics for chronic ocular graft-versus-host disease (GVHD). After considering the factors currently used to diagnose chronic ocular GVHD, the Consensus Group identified 4 subjective and objective variables to measure in patients following allogeneic hematopoietic stem cell transplantation (HSCT): OSDI, Schirmer's score without anesthesia, corneal staining, and conjunctival injection. Each variable was scored 0–2 or 0–3, with a maximum composite score of 11. Consideration was also given to the presence or the absence of systemic GVHD. On the basis of their composite score and the presence or absence of systemic GVHD, patients were assigned to one of three diagnostic categories: NO, PROBABLE, or DEFINITE ocular GVHD. New diagnostic criteria for chronic ocular GVHD are presented by the Consensus Group. Validation studies are needed to identify the best combination of the proposed metrics to maximize diagnostic sensitivity and specificity

Mortality risk of long-term amiodarone therapy for atrial fibrillation patients without structural heart disease

Background: Amiodarone is often prescribed in the management of atrial fibrillation (AF) but is known to cause significant end-organ toxicities. In this study, we examined the impact of amiodarone on all-cause mortality in AF patients with structurally normal hearts. Methods: We performed a retrospective cohort analysis of all AF patients with structurally normal hearts who were prescribed antiarrhythmic drugs (AAD) for rhythm control of AF at our institution from 2006 to 2013 (n = 2,077). Baseline differences between the amiodarone (AMIO: n = 403) and other AADs (NON-AMIO: n = 1,674) groups were corrected for using propensity score matching. Results: Amiodarone use as first-line therapy decreased significantly with a higher degree of prescriber specialization in arrhythmia management (31%, 22%, and 9% for primary care physicians, general cardiologists and cardiac electrophysiologists, respectively, p < 0.001). After propensity score matching, baseline comorbidities were balanced between the AMIO and NON-AMIO groups. Over a median follow-up of 28.2 months (range 6.0–100.9 months), amiodarone was associated with increased all-cause (HR 2.41, p = 0.012) and non-cardiac (HR 3.55, p = 0.008) mortality, but not cardiac mortality. AF recurrence and cardiac hospi­talizations were similar between the two study groups. Conclusions: Amiodarone treatment of AF is associated with increased mortality in patients without structural heart disease and therefore should be avoided or only used as a second-line therapy, when other AF therapies fail. Adherence to guideline recommendations in the management of AF patients impacts clinical outcome

Synthesis and characterization of silver nanoparticles by Murraya Koenigii leaves

Nanoparticles have a size of 1nm-100nm in any one of the three dimensions. Smaller nanoparticles have different physical, chemical and biological properties than atoms and molecules. Metals, non-oxide ceramic materials, metal oxides, silicates, and polymers, and organic and biomolecular components can be used to create material nanoparticles. Nanoparticles come in various shapes, like spheres, platelets, cylinders, and tubes. Green synthesized nanoparticles are not costly due to unemployment of toxic and hazardous compounds. Plants are widely spread, freely accessible, and safe to touch. They also supply a variety of metabolic compounds which are advantageous in reducing, capping and stabilizing process throughout in synthesis process. The reduction mechanism is based on the phytochemicals present in plant extract. In present work we synthesize silver nanoparticles by using Murraya Koenigii leaves through ecofriendly method. For synthesis of Silver nanoparticles, Silver nitrate (AgNO3 ) used as metal precursor salt and green extract of Murraya Koenigii used as reducing and capping agent for formation of nanoparticles. The nanoparticles then formed characterized by X-ray diffraction, Scanning electron microscope, Energy dispersive spectroscopy, Dynamic light scattering, Fourier transform infrared spectroscopy and optical properties by UV-Visible spectroscopy. XRD revealed the crystalline structure of silver nanoparticles, FESEM and Dynamic light scattering reveled the particle size of 60 nm, FTIR revealed the presence of different functional groups which are attached with sample and Optical properties of sample revealed by UV-Visible spectroscopy that also satis ies different experimental results

Associations Among Androgens, Estrogens, and Natriuretic Peptides in Young Women Observations From the Dallas Heart Study

ObjectivesWe sought to determine if natriuretic peptides are associated with estrogen and androgen status in a population study of young women without known cardiac disease.BackgroundCirculating concentrations of plasma B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are higher in women than in men, and they may be influenced by estrogens and androgens.MethodsCardiac magnetic resonance imaging, dual energy X-ray absorbtiometry, and measurements of BNP, NT-proBNP, follicle-stimulating hormone (FSH), total testosterone, and sex hormone-binding globulin (SHBG), were performed in 682 women (ages 35 to 49 years) participating in the Dallas Heart Study.ResultsIn multivariable analyses adjusting for age, race/ethnicity, body mass index (BMI), serum creatinine, left ventricular mass and left ventricular ejection fraction <55%, menopausal status, and FSH were not associated with BNP and NT-proBNP. In contrast, higher SHBG was associated with higher BNP and NT-proBNP, while the free androgen index and calculated free testosterone were inversely associated with BNP and NT-proBNP (p < 0.0001 for each). Addition of SHBG or any measure of free testosterone to the multivariable models modified the effect of BMI and lean mass, such that measures of body composition were no longer significantly associated with BNP or NT-proBNP.ConclusionsAmong young women, measures of free testosterone were independently and inversely associated with BNP and NT-proBNP. These results suggest that circulating free testosterone, not estradiol, mediates gender differences in natriuretic peptides. In addition, the association between higher BMI and lean body mass with natriuretic peptides may be mediated by testosterone

The impact of different fertiliser management options and cultivars on nitrogen use efficiency and yield for rice cropping in the Indo-Gangetic Plain: two seasons of methane, nitrous oxide and ammonia emissions

This study presents detailed crop and gas flux data from two years of rice production at the experimental farm of the ICAR-Indian Agricultural Research Institute, New Delhi, India. In comparing 4 nitrogen (N) fertiliser regimes across 4 rice cultivars (CRD 310, IR-64, MTU 1010, P-44), we have added to growing evidence of the environmental costs of rice production in the region. The study shows that rice cultivar can impact yields of both grain, and total biomass produced in given circumstances, with the CRD 310 cultivar showing consistently high nitrogen use efficiency (NUE) for total biomass compared with other tested varieties, but not necessarily with the highest grain yield, which was P-44 in this experiment. While NUE of the rice did vary depending on experimental treatments (ranging from 41% to 73%), 73%), this did not translate directly into the reduction of emissions of ammonia (NH3) and nitrous oxide (N2O). Emissions were relatively similar across the different rice cultivars regardless of NUE. Conversely, agronomic practices that reduced total N losses were associated with higher yield. In terms of fertiliser application, the outstanding impact was of the very high methane (CH4) emissions as a result of incorporating farmyard manure (FYM) into rice paddies, which dominated the overall effect on global warming potential. While the use of nitrification and urease inhibiting substances decreased N2O emissions overall, NH3 emissions were relatively unaffected (or slightly higher). Overall, the greatest reduction in greenhouse gas (GHG) emissions came from reducing irrigation water added to the fields, resulting in higher N2O, but significantly less CH4 emissions, reducing net GHG emission compared with continuous flooding. Overall, genetic differences generated more variation in yield and NUE than agronomic management (excluding controls), whereas agronomy generated larger differences than genetics concerning gaseous losses. This study suggests that a mixed approach needs to be applied when attempting to reduce pollution and global warming potential from rice production and potential pollution swapping and synergies need to be considered. Finding the right balance of rice cultivar, irrigation technique and fertiliser type could significantly reduce emissions, while getting it wrong can result in considerably poorer yields and higher pollution