1,924 research outputs found

    Choosing a density functional for static molecular polarizabilities

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    Coupled-cluster calculations of static electronic dipole polarizabilities for 145 organic molecules are performed to create a reference data set. The molecules are composed from carbon, hydrogen, nitrogen, oxygen, fluorine, sulfur, chlorine, and bromine atoms. They range in size from triatomics to 14 atoms. The Hartree-Fock and 2nd-order M{\o}ller-Plesset methods and 34 density functionals, including local functionals, global hybrid functionals, and range-separated functionals of the long-range-corrected and screened-exchange varieties, are tested against this data set. On the basis of the test results, detailed recommendations are made for selecting density functionals for polarizability computations on relatively small organic molecules

    Correlation of Theory and Experiment for the Dynamics of a Pressurized Water Reactor

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    Dynamic tests were performed on the Carolina Power and Light Company\u27s H. B. Robinson Unit 2 to determine the frequency response of the PWR steam supply system. Step inputs and multi-frequency binary signals of various sequence lengths and bit durations were used. The signals were introduced manually by the operator both for reactivity perturbation and steam flow perturbation tests. The experimental results were analyzed on and IBM 360/65 computer. The test results were compared with theoretical results predicted by a mathematical model of the system. A mathematical model for the H. B. Robinson system was formulated. In most cases, the experimental results were in good agreement with the results. An unexplained time delay of about nine to fourteen seconds was observed between the opening of the main steam valve and reactor coolant cold leg temperature. The time delay is much longer than the transport time

    2001 Bhuj-Kachchh earthquake: surface faulting and its relation with neotectonics and regional structures, Gujarat, Western India

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    Primary and secondary surface deformation related to the 2001 Bhuj-Kachchh earthquake suggests that thrusting movement took place along an E-W fault near the western extension of the South Wagad Fault, a synthetic fault of the Kachchh Mainland Fault (KMF). Despite early reconnaissance reports that concluded there was no primary surface faulting, we describe an 830 m long, 15-35 cm high, east-west-trending thrust fault scarp near where the seismogenic fault plane would project to the surface, near Bharodiya village (between 23°34.912'N, 70°23.942'E and 23°34.304'N, 70°24.884'E). Along most of the scarp Jurassic bedrock is thrust over Quaternary deposits, but the fault scarp also displaces Holocene alluvium and an earth dam, with dips of 13° to 36° south. Secondary co-seismic features, mainly liquefaction and lateral spreading, dominate the area south of the thrust. Transverse right-lateral movement along the «Manfara Fault» and a parallel fault near Bharodiya suggests segmentation of the E-W master faults. Primary (thrust) surface rupture had a length of 0.8 km, maximum displacement of about 35 cm, and average displacement of about 15 cm. Secondary (strike-slip) faulting was more extensive, with a total end-to-end length of 15 km, maximum displacement of 35 cm, and average displacement of about 20 cm

    Technique and Role of Embolization using Ethylene Vinyl-Alcohol Copolymer before Carotid Body Tumor Resection.

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    A 45-year old female referred for a large carotid body tumor resection. The tumor was encasing the internal (ICA) and external carotid arteries (ECA). She underwent angiogram and embolization of the ascending pharyngeal artery and a distal branch of the ECA using ethylene vinyl-alcohol copolymer (EVOH). Two days later, surgical resection of the tumor with regional lymph node dissection was performed along with an interposition reversed vein graft anastomosis between the mid common carotid and distal ICA. Devascularization of carotid body tumor can be performed using EVOH delivered through trans-arterial and percutaneous routes. Embolization may facilitate surgical resection and decrease blood loss but does not decrease the rate of neurological complications. Embolization can be performed by the vascular surgeon before a large carotid body tumor resection with minimal migration and or stroke risk

    Complications as indicators of quality assurance after 401 consecutive colorectal cancer resections: the importance of surgeon volume in developing colorectal cancer units in India

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    <p>Abstract</p> <p>Background</p> <p>The low incidence of colorectal cancer in India, coupled with absence of specialized units, contribute to lack of relevant data arising from the subcontinent. We evaluated the data of the senior author to better define the requirements that would enable development of specialized units in a country where colorectal cancer burden is increasing.</p> <p>Methods</p> <p>We retrospectively analyzed data of 401 consecutive colorectal resections from a prospective database of the senior author. In addition to patient demographics and types of resections, perioperative data like intraoperative blood loss, duration of surgery, complications, re-operation rates and hospital stay were recorded and analyzed.</p> <p>Results</p> <p>The median age was 52 years (10-86 years). 279 were males and 122 were females. The average duration of surgery was 220.32 minutes (range 50 - 480 min). The overall complication rate was 12.2% (49/401) with a 1.2% (5/401) mortality rate. The patients having complications had an increase in their median hospital stay (from 10.5 days to 23.4 days) and the re-operation rate in them was 51%. The major complications were anastomotic leaks (2.5%) and stoma related complications (2.7%).</p> <p>Conclusions</p> <p>This largest ever series from India compares favorably with global standards. In a nation where colorectal cancer is on the rise, it is imperative that high volume centers develop specialized units to train future specialist colorectal surgeons. This would ensure improved quality assurance and delivery of health care even to outreach, low volume centers.</p

    NON-DESTRUCTIVE RAMAN SPECTROSCOPIC METHOD FOR ESTIMATION OF MONTELUKAST FROM TABLET DOSAGES FORM

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    Objective: A rapid, non-destructive and non-solvent raman spectroscopic method for estimation of Montelukast from tablet dosages form Methods: Quantification was carried out by measuring the intensity of analyte peak at 1440 cm-1. Each Raman spectrum corresponded to an accumulation of 4 scans with an exposure time of 5 sec for each scan with a total integration time of 20 sec.Results: The method exhibited linearity between 2 mg-24 mg show well resolve quantification From MON. The linearity equation was calculated as y = 13.036x+70.819 and the correlation coefficient was found to be 0.997 for MON. LOD (limit of detection) and LOQ(limit of quantification) values were calculated using the calibration curve slope and standard deviation of the response. The LOD (limit of detection) and LOQ (limit of quantification) values were found to be 1.71 mg and 5.13 mg respectively.Conclusion: The developed method was successfully applied for assay of montelukast in the intact formulation. The method was validated according to an international conference on harmonisation guidelines. A recent study, montelukast sodium had been analysed by the raman method, but, looking into the tremendous potential of raman spectroscopic method; it can be extended as a process analysis and technology tool in various quality checks during manufacturing of pharmaceutical products
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