2,012 research outputs found

    EPR and Structural Characterization of Water-Soluble Mn2+-Doped Si Nanoparticles.

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    Water-soluble poly(allylamine) Mn2+-doped Si (SiMn) nanoparticles (NPs) were prepared and show promise for biologically related applications. The nanoparticles show both strong photoluminescence and good magnetic resonance contrast imaging. The morphology and average diameter were obtained through transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM); spherical crystalline Si NPs with an average diameter of 4.2 ± 0.7 nm were observed. The doping maximum obtained through this process was an average concentration of 0.4 ± 0.3% Mn per mole of Si. The water-soluble SiMn NPs showed a strong photoluminescence with a quantum yield up to 13%. The SiMn NPs had significant T1 contrast with an r1 relaxivity of 11.1 ± 1.5 mM-1 s-1 and r2 relaxivity of 32.7 ± 4.7 mM-1 s-1 where the concentration is in mM of Mn2+. Dextran-coated poly(allylamine) SiMn NPs produced NPs with T1 and T2 contrast with a r1 relaxivity of 27.1 ± 2.8 mM-1 s-1 and r2 relaxivity of 1078.5 ± 1.9 mM-1 s-1. X-band electron paramagnetic resonance spectra are fit with a two-site model demonstrating that there are two types of Mn2+ in these NP's. The fits yield hyperfine splittings (A) of 265 and 238 MHz with significant zero field splitting (D and E terms). This is consistent with Mn in sites of symmetry lower than tetrahedral due to the small size of the NP's

    Ab-initio Study of Structural, Electronic and Elastic Properties of ErCu

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    First principles density functional calculations were performed to study the structural, electronic, elastic and mechanical properties of erbium copper intermetallic compound (ErCu). The calculations are carried out within the generalized gradient approximation (GGA) for the exchange and correlation potential. The total energy as a function of volume is obtained by performing spin-polarized calculation. Magnetically the ErCu compound is stable in ferromagnetic (FM) state and its crystal structure is CsCl-type. Ground state properties such as lattice constant (a0), bulk modulus (B), its pressure derivative (B?) and magnetic moment (?B) are calculated. The density of states at the Fermi level, N(EF) and specific heat coefficient are also estimated in majority and minority spin channels. The electronic properties such as band structure and density of states (DOS) reveal that no band gap lead to metallic character of ErCu. The elastic constants (C11, C12 and C44) and mechanical properties such as Poisson’s ratio (? ), Young’s modulus (E), shear modulus (GH), anisotropic factor (A) are also calculated .  Ductility for these compounds is further analyzed by calculating  the ratio of (B/GH )  and Cauchy pressure (C12 - C44). Keywords: Density functional theory, Band structure, Density of states, Lattice constant, Bulk Modulus, Specific heat

    Efficacy and safety of hydroxychloroquine when added to stable insulin therapy in combination with metformin and glimepiride in patients with type 2 diabetes compare to sitagliptin

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    Background: The trial was done to evaluate the efficacy and tolerability of hydroxychloroquine when added to stable insulin therapy in combination with metformin and glimepiride in patients with type 2 diabetes (T2DM) compare to sitagliptin.Methods: After two weeks run in period, eligible patients inadequately controlled on long acting, intermediate acting or premixed insulin (HbA1c ≥7.5% and ≤10%), in combination with metformin and glimepiride were randomised 1:1 to the addition of once daily hydroxychloroquine 400mg or sitagliptin 100mg over 24weeks study period. The primary endpoint was HbA1c change from baseline at week 24. Home based glucometer was used to determine finger stick glucose value to detect hypo or hyperglycemia periodically.Results: At 24 weeks, the addition of hydroxychloroquine significantly (p <0.001) reduced HbA1c by 1.3% compared with Sitagliptin which was 0.9%. A greater proportion of patients achieved an HbA1c level <7% while randomised to Hydroxychloroquine as compared with sitagliptin (31 vs. 18% respectively; p <0.001). The addition of hydroxychloroquine significantly (p<0.001) reduced fasting plasma glucose by 31.0mg/dl (vs 23.2mg/dl with sitagliptin) and post prandial plasma glucose by 52.1mg/dl (vs 41mg/dl with sitagliptin) relative to sitagliptin. The difference in mean value of total daily insulin dose showed a highly significant decrease (P <0.0001) from baseline to end of the treatment with hydroxychloroquine i.e. from 41±10.2 to 31.87±16.49 IU as compare to sitagliptin i.e. from 41±10.6 to 37.91±11.71 IU. And also highly significant (P <0.0001) decrease in mean weight was observed at the end of trial with hydroxychloroquine.Conclusions: Hydroxychloroquine decreases HbA1c in patients whose type 2 diabetes is poorly controlled with stable-dose insulin therapy with metformin and glimepiride

    Roots of Pennisetum sp. possess the competence to generate nanoparticles of noble metals

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    461-467Roots of plants have immense reducing potential. Ions of noble metals namely Au3+ and Ag+ get reduced easily to form Au and Ag nanoparticles (NPs), respectively. Therefore, we hypothesize that plant roots could have potential to form Au-NPs and Ag-NPs. For present investigations, plants of Pennisetum glaucum L. were used to evaluate if their roots possess capacity to generate metal NPs. The generation of Au-NPs and Ag-NPs was initially presumed based on colour change, and confirmed by UV-vis spectra, TEM and EDX investigations. Pale yellow Au3+ and colourless Ag+ solutions turned purple and brown, respectively, by roots of Pennisetum sp. within 8 h. Absorption spectra of respective solutions showed plasmon resonance band at 560 nm and 420 nm confirming the presence of Au-NPs and Ag-NPs. TEM coupled with SAED revealed the presence of crystalline spherical NPs in the size range of 5-50 nm in these solutions. EDX further confirmed the presence of Au and Ag as NPs of respective solutions. These results confirmed that the roots of P. glaucum possess ideal reducing strength to generate Au-NPs and Ag-NPs exogenously in the aqueous phase

    Role of physical and engineering properties of rice (Oryza sativa) cultivars for designing of precision planter

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    The paper describes the effect of physical and engineering properties of five rice (Oryza sativa L.) cultivars, viz. Pusa 1121, Pusa 44, BPT 5205, MTU 7209 and MTU 1010 on the design parameters of precision planter for direct sowing of rice seeds in drylands. The properties were determined in three conditions of seeds, viz. dry condition, 1- day soaking and two day soaking condition. In all the five selected varieties, no significant difference in length was found between dry and soaked seed, while breadth and thickness of the seeds were found slight increase in all varieties. It was observed that the grain length varied from 7.32±0.61 to 13.79±0.93 mm, breadth 2.16±0.21 to 2.58±0.06 mm, sphericity, 43.66±2.45 to 30.56±3.49, 1000 grain-weight 14.37 to 32.6 g, angle of repose 25.25 to 33.68° and bulk density 524.6 to 667.56 kg/m3.The observed values can be used to fabricate the seed metering cells for different varieties with cell diameter ranging from 10 mm to 14 mm. Thickness and cell diameters of the seed metering discs were designed in reference to the maximum breadth and length. Based on the results, it can be revealed that flow rate from the hopper can be affected due to angle of repose and coefficient of friction for rice grains. Thus, to design the hopper the average values of angle of repose and coefficient of friction can be taken. The highest angle of repose observed in PUSA 1121 can be used to have a seed hopper slope of 35° to ensure free flow of seed. The coefficient of friction in all the selected varieties was less with mild steel as compared to galvanized-iron and wood surfaces. It was concluded that a minimum angle of 30°and a plate thickness of 4 mm can be used to design a hopper by selecting the low friction mild steel sheet. The measured bulk density and size values can be used to design a hopper of required capacity and seed metering plate cell size for required number of seeds/hill

    Struggling to a monumental triumph : Re-assessing the final stages of the smallpox eradication program in India, 1960-1980

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    The global smallpox program is generally presented as the brainchild of a handful of actors from the WHO headquarters in Geneva and at the agency's regional offices. This article attempts to present a more complex description of the drive to eradicate smallpox. Based on the example of India, a major focus of the campaign, it is argued that historians and public health officials should recognize the varying roles played by a much wider range of participants. Highlighting the significance of both Indian and international field officials, the author shows how bureaucrats and politicians at different levels of administration and society managed to strengthen—yet sometimes weaken—important program components. Centrally dictated strategies developed at WHO offices in Geneva and New Delhi, often in association with Indian federal authorities, were reinterpreted by many actors and sometimes changed beyond recognition

    Type and duration of subsyndromal symptoms in youth with bipolar I disorder prior to their first manic episode

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    Objectives: The aim of the present study was to systematically evaluate the prodrome to mania in youth. Methods: New-onset/worsening symptoms/signs of \u3e= moderate severity preceding first mania were systematically assessed in 52 youth (16.2 +/- 2.8 years) with a research diagnosis of bipolar I disorder (BD-I). Youth and/or caregivers underwent semi-structured interviews, using the Bipolar Prodrome Symptom Scale-Retrospective. Results: The mania prodrome was reported to start gradually in most youth (88.5%), with either slow (59.6%) or rapid (28.8%) deterioration, while a rapid-onset-and-deterioration prodrome was rare (11.5%). The manic prodrome, conservatively defined as requiring \u3e= 3 symptoms, lasted 10.3 +/- 14.4 months [95% confidence interval (CI): 6.3-14.4], being present for \u3e= 4 months in 65.4% of subjects. Among prodromal symptoms reported in \u3e= 50% of youth, three were subthreshold manic in nature (irritability: 61.5%, racing thoughts: 59.6%, increased energy/activity: 50.0%), two were nonspecific (decreased school/work functioning: 65.4%, mood swings/lability: 57.7%), and one each was depressive (depressed mood: 53.8%) or subthreshold manic/depressive (inattention: 51.9%). A decreasing number of youth had \u3e= 1 (84.6%), \u3e= 2 (48.1%), or \u3e= 3 (26.9%) \u27specific\u27 subthreshold mania symptoms (i.e., elation, grandiosity, decreased need for sleep, racing thoughts, or hypersexuality), lasting 9.5 +/- 14.9 months (95% CI: 5.0-14.0), 3.5 +/- 3.5 months (95% CI: 2.0-4.9), and 3.0 +/- 3.2 months (95% CI: 1.0-5.0) for \u3e= 1, \u3e= 2, or \u3e= 3 specific symptoms, respectively. Conclusions: In youth with BD-I, a relatively long, predominantly slowonset mania prodrome appears to be common, including subthreshold manic and depressive psychopathology symptoms. This suggests that early clinical identification and intervention may be feasible in bipolar disorder. Identifying biological markers associated with clinical symptoms of impending mania may help to increase chances for early detection and prevention before full mania

    Pressure versus concentration tuning of the superconductivity in Ba(Fe(1-x)Cox)2As2

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    In the iron arsenide compound BaFe2As2, superconductivity can be induced either by a variation of its chemical composition, e.g., by replacing Fe with Co, or by a reduction of the unit-cell volume through the application of hydrostatic pressure p. In contrast to chemical substitutions, pressure is expected to introduce no additional disorder into the lattice. We compare the two routes to superconductivity by measuring the p dependence of the superconducting transition temperature Tc of Ba(Fe(1-x)Cox)2As2 single crystals with different Co content x. We find that Tc(p) of underdoped and overdoped samples increases and decreases, respectively, tracking quantitatively the Tc(x) dependence. To clarify to which extent the superconductivity relies on distinct structural features we analyze the crystal structure as a function of x and compare the results with that of BaFe2As2 under pressure.Comment: 14 pages, 4 figures, to be published in JPSJ Vol. 79 No. 12. The copyright is held by The Physical Society of Japa

    Chief digital officers:An analysis of the presence of a centralized digital transformation role

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    By appointing a chief digital officer (CDO), firms decide for a central role responsible for their digital transformation. While CDOs have recently appeared in the C-suites of firms across the globe, the current literature lacks insights into the specific antecedents of CDO presence. Grounded in the peculiarities of the digital age, we provide theoretical arguments explaining how the decision to centralize digital transformation responsibilities might be related to transformation urgency and coordination needs. Empirical analyses based on a panel data set of 913 U.S. and European firms support that transformation urgency and coordination needs predict CDO presence. An additional analysis of moderating temporal effects reveals that, over time, the effect of transformation urgency is weakened and the effect of coordination needs on CDO presence is strengthened. We discuss implications for research and practice regarding the antecedents of CDO presence, TMT research more generally, and centralization in the digital age
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