3,707 research outputs found
Two-dimensional semiconductor alloys: Monolayer Mo1-xWxSe2
No full textMonolayer Mo1-xWxSe2 (x = 0, 0.14, 0.75, and 1) alloys were experimentally realized from synthesized crystals. Mo1-xWxSe2 monolayers are direct bandgap semiconductors displaying high luminescence and are stable in ambient. The bandgap values can be tuned by varying the W composition. Interestingly, the bandgap values do not scale linearly with composition. Such non-linearity is attributed to localization of conduction band minimum states around Mo d orbitals, whereas the valence band maximum states are uniformly distributed among W and Mo d orbitals. Results introduce monolayer Mo1-xWxSe2 alloys with different gap values, and open a venue for broadening the materials library and applications of two-dimensional semiconductors
Lessons from diagnosis-prescribing and antibiotic resistance surveillance in Ujjain, India : the lull before the storm
No full textBackground: The evolution of antibiotic resistance is a global public health crisis building over decades. In this build-up antibiotic use has been the main driver for antibiotic resistance. To develop context-specific interventions, effective surveillance of antibiotic use and resistance are needed in counties like India, which have witnessed a rapid rise in resistance recently and where the need for effective antibiotics is high.Aim: The main aim of this thesis is to increase the knowledge regarding antibiotic prescribing patterns and prevalence of resistance in an Indian setting, so as to identify targets for interventions aimed to improve clinical practice for common infections.Methods: This thesis includes five cross-sectional studies. Paper I and paper II describes the patterns of antibiotic prescribing for outpatients with suspected infectious aetiology and among admitted patients, respectively. The defined daily doses (DDDs) were calculated per 1000 patients per diagnosis considered in paper I. Focus of infection specific DDDs were calculated per 100 patient days in paper II. In paper III, prescriptions for children with diarrhoea were analysed for adherence to treatment guidelines and factors associated with adherence were explored. In paper IV healthy children were screened for nasal carriage of S. aureus to identify factors associated with nasal carriage and to describe the resistance patterns. Paper V describes the antibiotic susceptibility pattern of pathogens isolated from patients with suspected infections. Antibiotic susceptibility testing was performed by Kirby-Bauer disk-diffusion method. All the studies were done using structured, pilot tested questionnaires.Results: Overall antibiotic prescribing was 66.3%, 3732 out of 5623 outpatients (Paper I) and 92%, 5531 out of 6026 admitted patients (Paper II). Quinolones were the most frequently prescribed antibiotic group among outpatients and third generation cephalosporins among the admitted patients (Paper I and II). For diarrhoea in children only 6 out of 843 prescriptions adhered completely to treatment guidelines. Oral rehydration solution (ORS) was prescribed for 58%, ORS with zinc for 22% and antibiotics for 71% of the cases (Paper III). The prevalence of nasal carriage of S. aureus was 98 out of 1562 i.e. 6.3% (95% confidence interval [CI] 5.1-7.5). Of these, 16.3% were methicillin-resistant S. aureus (MRSA). Overcrowding was associated with nasal carriage of S. aureus (Paper IV). Among pathogens (n=716) isolated form admitted patients (n=2568), Gram-negative pathogens predominated (62%). Extendedspectrum β-lactamase (ESBL) production in E. coli isolates (n=149) was 69% (95% CI 61.6–76.6) and in K. pneumoniae isolates (n=107), 41% (95% CI 31.6–50.5). MRSA constituted 30% of all S. aureus isolates (n=221).Conclusions: The targets identified for interventions were: high antibiotic prescribing rates for diarrhoea (Paper I, II and III) and upper respiratory tract infection (Paper I). Other targets include, longer than recommended duration of prophylaxis (86% of 1846 patients) and lack of distinction between prophylaxis and therapy among surgical patients, irrational antibiotic prescribing in gastroenteritis, overuse of quinolones and lack of use of penicillin in pneumonia, overuse of quinolones and lack of use of doxycycline and macrolides in genital infections, and overreliance on antibiotics in treating skin and soft tissue infections (Paper II). The high rate of antibiotic prescribing among admitted patients together with the high rates of ESBL producing pathogens shows urgent need to curb antibiotic use when there is no indication for it (Paper V).List of scientific papersI. Pathak A, Mahadik K, Dhaneria SP, Sharma A, Eriksson B, Stålsby Lundborg C. Antibiotic prescribing in outpatients: Hospital and seasonal variations in Ujjain, India. Scand J Infect Dis. 2011 Jul, 43(6-7): 479-88. https://doi.org/10.3109/00365548.2011.554854 II. Pathak A, Mahadik K, Dhaneria SP, Sharma A, Eriksson B and Stålsby Lundborg C. Surveillance of antibiotic consumption using “focus of infection” approach in Ujjain, India. [Submitted]III. Pathak D, Pathak A, Marrone G, Diwan V, Stålsby Lundborg C. Adherence to treatment guidelines for acute diarrhoea in children up to 12 years in Ujjain, India-a cross-sectional prescription analysis. BMC Infect Dis. 2011 Jan 28; 11:32. https://doi.org/10.1186/1471-2334-11-32 IV. Pathak A, Marothi Y, Iyer RV, Singh B, Sharma M, Eriksson B, Macaden R, Stålsby Lundborg C. Nasal carriage and antimicrobial susceptibility of Staphylococcus aureus in healthy preschool children in Ujjain, India. BMC Pediatr. 2010 Dec 29; 10:100. https://doi.org/10.1186/1471-2431-10-100 V. Pathak A, Marothi Y, Kekre V, Mahadik K, Macaden R and Stålsby Lundborg C. High prevalence of extended-spectrum β-lactamase producing pathogens: Results of a surveillance study in 2 hospitals, Ujjain, India. Infect and Drug Resist. 2012, 5:65-73. https://doi.org/10.2147/IDR.S30043 </p
Corrigendum: Proceedings of the 12th annual deep brain stimulation think tank: cutting edge technology meets novel applications
No full textIn the published article, there was an error in the author list and author Sarah-Anna Hescham was erroneously excluded. The corrected author list appears below. “Alfonso Enrique Martinez-Nunez 1*, Christopher J. Rozell 2, Simon Little 3, Huiling Tan 4, Stephen L. Schmidt 5, Warren M. Grill 5,6, Miroslav Pajic 5, Dennis A. Turner 5,6,7, Coralie de Hemptinne 1, Andre Machado 8,9, Nicholas D. Schiff 10, Abbey S. Holt-Becker 11, Robert S. Raike 11, Mahsa Malekmohammadi 12,13, Yagna J. Pathak 14, Lyndahl Himes 14, David Greene 15, Lothar Krinke 16,17, Mattia Arlotti 16, Lorenzo Rossi 16, Jacob Robinson 18,19, Bahne H. Bahners 20,21,22, Vladimir Litvak 23, Luka Milosevic 24,25, Saadi Ghatan 26,27, Frederic L. W. V. J. Schaper 20, Michael D. Fox 20, Nicholas M. Gregg 28, Cynthia Kubu 8, James J. Jordano 29,30,31, Nicola G. Cascella 32, YoungHoon Nho 33, Casey H. Halpern 33,34, Helen S. Mayberg 35,36,37, Ki Sueng Choi 35,36, Haneul Song 35, Jungho Cha 35, Sankaraleengam Alagapan 2, Nico U. F. Dosenbach 38,39,40,41,42,43, Evan M. Gordon 44, Jianxun Ren 45, Hesheng Liu 45,46, Lorraine V. Kalia 47,48, Sarah-Anna Hescham 49,50,51, Dorian M. Kusyk 1, Adolfo Ramirez-Zamora 1, Kelly D. Foote 1, Michael S. Okun 1 and Joshua K. Wong 1.” The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.</p
Freezing of Heavy Water (D<sub>2</sub>O) Nanodroplets
No full textWe follow the freezing of heavy water
(D2O) nanodroplets
formed in a supersonic nozzle apparatus using position resolved pressure
trace measurements, Fourier transform infrared spectroscopy, and small-angle
X-ray scattering. For these 3–9 nm radii droplets, freezing
starts between 223 and 225 K, at volume based ice nucleation rates Jice,V on the order of 1023 cm–3 s–1 or surface based ice nucleation
rates Jice,S on the order of 1016 cm–2 s–1. The temperatures corresponding
to the onset of D2O ice nucleation are higher than those
reported for H2O by Manka et al. [Manka, A.; Pathak, H.;
Tanimura, S.; Wölk, J.; Strey, R.; Wyslouzil, B. E. Phys. Chem. Chem. Phys. 2012, 14, 4505]. Although the values of Jice,S scale somewhat better with droplet size than values of Jice,V, the data are not accurate enough to state that
nucleation is surface initiated. Finally, using current estimates
of the thermophysical properties of D2O and the theoretical
framework presented by Murray et al. [Murray, B. J.; Broadley, S.
L.; Wilson, T. W.; Bull, S. J.; Wills, R. H.; Christenson, H. K.;
Murray, E. J. Phys. Chem. Chem. Phys. 2010, 12, 10380], we find that the theoretical ice nucleation
rates are within 3 orders of magnitude of the measured rates over
an ∼15 K temperature range
Differential regulation of p38 mitogen-activated protein kinase mediates gender-dependent catecholamine-induced hypertrophy
No full textObjective: Exogenous catecholamine exposure has been associated with p38 mitogen-activated protein kinase (MAPK) and cardiac hypertrophy. In this study, we investigated the regulation of p38 MAPK in cardiac remodeling elicited by endogenous adrenergic mechanisms. Methods: Transgenic male and female mice with fourfold phospholamban (PLB) overexpression exhibited enhanced circulating norepinephrine (NE). as a physiological compensatory mechanism to attenuate PLB's inhibitory effects. This enhanced noradrenergic state resulted in left ventricular hypertrophy/dilatation and depressed function. Results: Male transgenics exhibited ventricular hypertrophy and mortality at 15 months, concurrent with cardiac p38 MAPK activation. Female transgenics, despite similar contractile dysfunction, displayed a temporal delay in p38 activation, hypertrophy, and mortality (22 months), which was associated with sustained cardiac levels of MAP Kinase Phosphatase-1 (MKP-1), a potent inhibitor of p38. At 22 months, decreases in cardiac MKP-1 were accompanied by increased levels of p38 activation. In vitro studies indicated that preincubation with 17-beta-estradiol induced high MKP-1 levels, which precluded NE-induced p38 activation. Conclusion: These findings suggest that norepinephrine-induced hypertrophy is linked closely with p38 MAP kinase activation, which can be endogenously modulated through estrogen-responsive regulation of MKP-1 expression. (C) 2003 European Society of Cardiology. Published by Elsevier Science B.V. All rights reserved.NCRR NIH HHS [P40RR12358]; NHLBI NIH HHS [HL-52318, HL-64018, HL-26057
Aggressive Risk factor REduction STudy for Atrial Fibrillation (ARREST-AF) implications for ablation outcomes: A Randomized Clinical Trial
No full text2024 AHA Late-Breaking Science Abstracts - 4171701Rajeev Pathak, Adrian Elliott, Dennis Lau, Melissa Middeldorp, Dominik Linz, John Fitzgerald, Jonathan Ariyaratnam, Varun Malik, Jean Jacques Noubiap, Rajiv Mahajan, Walter Abhayaratna, Jonathan Kalman, Prashanthan Sander
Linear Isometries of Spaces of Absolutely Continuous Functions
No full textLet X be an arbitrary compact subset of the real line R which has at least two points. For each finite complex valued function f on X we denote by V(f; X) (and call it the weak variation of f on X) the least upper bound of the numbers ∑i|f(bi) – f(ai)| where {[ai, bi]} is any sequence of non-overlapping intervals whose end points belong to X. A function f is said to be of bounded variation (BV) on X if V(f; X) < ∞. A function f is said to be absolutely continuous (AC) on X, if given any ∈ > 0 there exists an n > 0 such that for every sequence of non-overlapping intervals {[au bi]} whose end points belong to X, the inequalityimplies that([7], p. 221, 223).
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First-order magnetic phase transition in Pr2In with negligible thermomagnetic hysteresis
No full textMagnetic first-order phase transitions are key for the emergence of functionalities of fundamental and applied significance, including magnetic shape memory as well as magnetostrictive and magnetocaloric effects. Such transitions are usually associated with thermomagnetic hysteresis. We report the observation of a first-order transition in Pr2In from a paramagnetic to a ferromagnetic state at TC=57K without a detectable thermomagnetic hysteresis, which is also accompanied by a large magnetocaloric effect. The peculiar electronic structure of Pr2In exhibiting a large density of states near the Fermi energy explains the highly responsive magnetic behavior of the material. The magnetic properties of Pr2In are reported, including observation of another (second-order) magnetic transition at 35 K.This article is published as Biswas, Anis, N. A. Zarkevich, Arjun K. Pathak, O. Dolotko, Ihor Z. Hlova, A. V. Smirnov, Y. Mudryk, D. D. Johnson, and V. K. Pecharsky. "First-order magnetic phase transition in Pr2In with negligible thermomagnetic hysteresis." Physical Review B 101, no. 22 (2020): 224402. DOI: 10.1103/PhysRevB.101.224402. Posted with permission.</p
Fruit crops, 1986: a summary of research
No full textInfluence of treatments at planting on trellised apple tree performance / David C. Ferree -- Influence of growth regulators on branching of young apple trees / David C. Ferree and John C. Schmid -- Influence of growth regulators on scarf skin of Rome Beauty apples / David C. Ferree and John C. Schmid -- Influence of fungicides on scarf skin on Gallia Beauty / David C. Ferree and Michael A. Ellis -- Little relationship between root pruning and winter injury / James R. Schupp and David C. Ferree -- Performance of two apple cultivars on MS and M9 interstems on Antonovka / D. C. Ferree, R. M. McConnell, and J. C. Schmid -- Air sprayer jet deflection by travel or wind: as predicted by computer / R. D. Fox, R. D. Brazee, and D. L. Reichard -- Measuring atmospheric water vapor / R. D. Brazee and R. D. Fox -- A prototypic pollination unit made from expanded polystyrene / James E. Tew and Dewey M. Caron -- Effects of gibberellic acid (GA3) and daminozide (Alar) on growth and fruiting of Himrod grapes / G. A. Cahoon, M. L. Kaps, and S. P. Pathak -- Development of an action threshold for meadow spittlebug on strawberries / Mark A. Zajac and Franklin R. Hall -- Long-term yield of selected blackberry cultivars and selections in southern Ohio / Craig K. Chandler, Donald A. Chandler, and Greg L. Brenneman -- Electronic information transfer / R. C. Funt. -- A summary of research on synthetic pyrethroids and mites in the apple orchard ecosystem / Franklin R. Hall -- Controlling apple collar rot: effects of fungicides, soil amendments, and depth of planting / M. A. Ellis, D. C. Ferree, and L. V. Madden -- Validation of an electronic unit for predicting apple scab infection periods / M. A. Ellis, L. V. Madden, and L. L. Wilson -- Epidemiology and control of strawberry leather rot / G. G. Grove, M. A. Ellis, and L. V. Madden -- Research on cane diseases of thornless blackberry in Ohio / M. A. Ellis, G. A. Kuter, and L. L. Wilso
Mechanics of Heavy Oil and Bitumen Recovery by Hot Solvent Injection
No full textAbstract
In our earlier works (Pathak et al., 2010; 2011), we presented the initial results for heavy oil and bitumen recovery using heated solvent vapours. The heavy oil and bitumen saturated sand pack samples of different heights were exposed to heated vapours of butane or propane at a constant temperature and pressure for an extended duration of time. The produced oil was analyzed for recovery, asphaltene content, viscosity, composition and refractive index. Recovery was found to be very sensitive to temperature and pressure.
The current work was undertaken to better understand the physics of the process and to explain the observations of the earlier experiments using additional experiments on tighter samples of different sizes, numerical simulation and visualization experiments. The effects of temperature and pressure on the recovery were studied using a commercial reservoir simulator. Propane and butane were used as solvents. Asphaltene precipitation was also modeled. A qualitative history match with the experiments on different porous media types was achieved by mainly considering the permeability reduction due to asphaltene precipitation, pore plugging, the extent of interaction between solvent and oil phase, and the parameters like model height, vertical permeability and gravity.
To investigate the phenomenon further, visualization experiments were performed. 2-D Hele-Shaw models were constructed by joining two plexiglass sheets from three sides, leaving some space in between to accommodate oil. The models were saturated with heavy-oil and left open from one side and were exposed to different types of solvents from this side. The setup was continuously monitored to observe fluid fronts and asphaltene precipitation.
Using this analysis, the mechanics of the process was clarified from the effect of solvent type on the recovery process. The optimum operating temperature for the hot solvent process and the dominant mechanisms were identified.</jats:p
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