448 research outputs found
Experimental Hamiltonian identification for controlled two-level systems
We present a strategy to empirically determine the internal and control Hamiltonians for an unknown two-level system (black box) subject to various (piecewise constant) control fields when direct readout by measurement is limited to a single, fixed observable
Experimental Hamiltonian Identification for Qubits subject to Multiple Independent Control Mechanisms
We consider a qubit subject to various independent control mechanisms and
present a general strategy to identify both the internal Hamiltonian and the
interaction Hamiltonian for each control mechanism, relying only on a single,
fixed readout process such as measurements.Comment: submitted to Proceedings of the QCMC04 (4 pages RevTeX, 5 figures
Genetic Locus Required for Antigenic Maturation of \u3cem\u3eRhizobium etli\u3c/em\u3e CE3 Lipopolysaccharide
Rhizobium etli modifies lipopolysaccharide (LPS) structure in response to environmental signals, such as low pH and anthocyanins. These LPS modifications result in the loss of reactivity with certain monoclonal antibodies. The same antibodies fail to recognize previously isolated R. etli mutant strain CE367, even in the absence of such environmental cues. Chemical analysis of the LPS in strain CE367 demonstrated that it lacked the terminal sugar of the wild-type O antigen, 2,3,4-tri-O-methylfucose. A 3-kb stretch of DNA, designated as lpe3, restored wild-type antigenicity when transferred into CE367. From the sequence of this DNA, five open reading frames were postulated. Site-directed mutagenesis and complementation analysis suggested that the genes were organized in at least two transcriptional units, both of which were required for the production of LPS reactive with the diagnostic antibodies. Growth in anthocyanins or at low pH did not alter the specific expression of gusA from the transposon insertion of mutant CE367, nor did the presence of multiple copies of lpe3 situated behind a strong, constitutive promoter prevent epitope changes induced by these environmental cues. Mutations of the lpe genes did not prevent normal nodule development on Phaseolus vulgaris and had very little effect on the occupation of nodules in competition with the wild-type strain
Effect of guidewire on contribution of loss due to momentum change and viscous loss to the translesional pressure drop across coronary artery stenosis: An analytical approach
<p>Abstract</p> <p>Background</p> <p>Guidewire (GW) size and stenosis dimensions are the two major factors affecting the translesional pressure drop. Studying the combined effect of these parameters on the mean pressure drop (Î<it>p</it>) across the stenosis is of high practical importance.</p> <p>Methods</p> <p>In this study, time averaged mass and momentum conservation equations are solved analytically to obtain pressure drop-flow, Î<it>p</it>-<it>Q</it>, curves for three different percentage area blockages corresponding to moderate (64%), intermediate (80%), and severe (90%) stenoses. Stenosis is considered to be axisymmetric consisting of three different sections namely converging, throat, and diverging regions. Analytical expressions for pressure drop are obtained for each of these regions separately. Using this approach, effects of lesion length and GW insertion on the mean translesional pressure drop and its component (loss due to momentum change and viscous loss) are analyzed.</p> <p>Results and Conclusion</p> <p>It is observed that for a given percent area stenosis (AS), increase in the throat length only increases the viscous loss. However, increase in the severity of stenosis and GW insertion increase both loss due to momentum change and viscous loss. GW insertion has greater contribution to the rise in viscous loss (increase by 2.14 and 2.72 times for 64% and 90% AS, respectively) than loss due to momentum change (1.34% increase for 64% AS and 25% decrease for 90% AS). It also alters the hyperemic pressure drop in moderate (48% increase) to intermediate (30% increase) stenoses significantly. However, in severe stenoses GW insertion has a negligible effect (0.5% increase) on hyperemic translesional pressure drop. It is also observed that pressure drop in a severe stenosis is less sensitive to lesion length variation (4% and 14% increase in Î<it>p </it>for without and with GW, respectively) as compared to intermediate (10% and 30% increase in Î<it>p </it>for without and with GW, respectively) and moderate stenoses (22% and 48% increase in Î<it>p </it>for without and with GW, respectively). Based on the contribution of pressure drop components to the total translesional pressure drop, it is found that viscous losses are dominant in moderate stenoses, while in severe stenoses losses due to momentum changes are significant. It is also shown that this simple analytical solution can provide valuable information regarding interpretation of coronary diagnostic parameters such as fractional flow reserve (FFR).</p
MOLECULAR DOCKING STUDIES OF SOME NOVEL THIOPHENE CARBOHYDRAZIDE DERIVATIVES ON ENTEROTOXIN OF BACILLUS CEREUS
Objective: In this work, we collected the three-dimensional structure of Enterotoxin from Bacillus cereus which plays an important role in the pathway.
Methods: The protein structure was collected from PDB data bank. From the 3D structures of the proteins, the targeted derivatives were designed. Docking studies were performed with designed compounds.
Results: The compounds docked to the protein by hydrogen bonding interactions and these interactions play an important role in the binding studies. Docking results showed the best compounds among the derivatives.
Conclusion: The docking results agreed well with the observed in vitro data, in which the anti-microbial activity of the analogs was higher than other drugs and formed hydrogen bonds
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Prospective Phase II trial of drug-eluting bead chemoembolization for liver transplant candidates with hepatocellular carcinoma and marginal hepatic reserve.
Purpose: To determine whether chemoembolization using drug-eluting beads (DEB-TACE) is safe and effective for liver transplantation candidates with liver-limited hepatocellular carcinoma (HCC) without vascular invasion and baseline hepatic dysfunction. Materials and methods: Seventeen adult liver transplantation candidates (median age 66 years, range 58-73 years; 13 men) with HCC were treated with DEB-TACE as a part of Stage 1 of a prospective single-institution Phase II trial. All patients had marginal hepatic reserve based on at least one of the following criteria: ascites (n=14), bilirubin between 3 and 6 mg/dL (n=5), AST 5-10 times upper normal limit (n=1), INR between 1.6 and 2.5 (n=4), portal vein thrombosis (n=2), and/or portosystemic shunt (n=2). Primary study objectives were safety and best observed radiographic response. Results: Thirty-seven DEB-TACE procedures were performed. Objective response rate and disease control rate were 63% and 88%, respectively. HCC progression was observed in 12 patients. Median time to progression was 5.6 months (range 0.9-13.6 months). Within 1 month following DEB-TACE, 13 patients (76%) developed grade 3 or 4 AE attributable to the procedure. Four patients (all within Milan Criteria) were transplanted (2.7-6.9 months after DEB-TACE), and 12 patients died (1.8-32 months after DEB-TACE). All deaths were due to liver failure that was either unrelated to HCC (n=5), in the setting of metastatic HCC (n=5), or in the setting of locally advanced HCC (n=2). Mortality rate at 1 month was 0%. Conclusions: DEB-TACE achieves tumor responses but carries a high risk of hepatotoxicity for liver transplant candidates with HCC and marginal hepatic reserve
FORMULATION AND EVALUATION OF VILDAGLIPTIN SUSTAINED RELEASE MATRIX TABLETS
Vildagliptin belongs to a class of orally active anti-diabetic drug which inhibits dipeptidyl peptidase-4(DPP-4) and to potentiate the secretion of insulin in the ĂÂČ-cells, there by decreasing blood glucose level. Vildagliptin is a short half life drug so it needs to formulate into sustained release dosage form to reduce dose frequency for patient compliance. Among various techniques, formulation of matrix tablets using matrix formers is a simple and industrially useful technique in the design of sustained release drug delivery systems. In the present study, an attempt has been made to develop sustained release matrix tablets of Vildagliptin using hydrophilic polymers like HPMC (k15M, K100M) and Carbapol by using wet granulation method. Dissolution study was done by using type-II dissolution apparatus gave good results with combination of HPMC K100 M and Carbapol. Drug release from the formulation follows zero order, first order, Higuchi's equation, and korsemeyer's equation
Studies of concentration and temperature dependencies of precipitation kinetics in iron-copper alloys using kinetic monte carlo and stochastic statistical simulations
The earlier-developed ab initio model and the kinetic Monte Carlo method
(KMCM) are used to simulate precipitation in a number of iron-copper alloys
with different copper concentrations x and temperatures T. The same simulations
are also made using the improved version of the earlier-suggested stochastic
statistical method (SSM). The results obtained enable us to make a number of
general conclusions about the dependencies of the decomposition kinetics in
Fe-Cu alloys on x and T. We also show that the SSM describes the precipitation
kinetics in a fair agreement with the KMCM, and employing the SSM in
conjunction with the KMCM enables us to extend the KMC simulations to the
longer evolution times. The results of simulations seem to agree with available
experimental data for Fe-Cu alloys within statistical errors of simulations and
the scatter of experimental results. Comparison of results of simulations to
experiments for some multicomponent Fe-Cu-based alloys enables us to make
certain conclusions about the influence of alloying elements in these alloys on
the precipitation kinetics at different stages of evolution.Comment: 18 pages, 17 postscript figures, LaTe
Crop type identification and spatial mapping using Sentinel-2 satellite data with focus on field-level information
Accurate monitoring of croplands helps in making decisions (for
insurance claims, crop management and contingency plans) at
the macro-level, especially in drylands where variability in cropping
is very high owing to erratic weather conditions. Dryland
cereals and grain legumes are key to ensuring the food and nutritional
security of a large number of vulnerable populations living
in the drylands. Reliable information on area cultivated to such
crops forms part of the national accounting of food production
and supply in many Asian countries, many of which are employing
remote sensing tools to improve the accuracy of assessments
of cultivated areas. This paper assesses the capabilities and limitations
of mapping cultivated areas in the Rabi (winter) season and
corresponding cropping patterns in three districts characterized
by small-plot agriculture. The study used Sentinel-2 Normalized
Difference Vegetation Index (NDVI) 15-day time-series at 10m
resolution by employing a Spectral Matching Technique (SMT)
approach. The use of SMT is based on the well-studied relationship
between temporal NDVI signatures and crop phenology. The
rabi season in India, dominated by non-rainy days, is best suited
for the application of this method, as persistent cloud cover will
hamper the availability of images necessary to generate clearly
differentiating temporal signatures. Our study showed that the
temporal signatures of wheat, chickpea and mustard are easily
distinguishable, enabling an overall accuracy of 84%, with wheat
and mustard achieving 86% and 94% accuracies, respectively. The
most significant misclassifications were in irrigated areas for mustard
and wheat, in small-plot mustard fields covered by trees and
in fragmented chickpea areas. A comparison of district-wise
national crop statistics and those obtained from this study
revealed a correlation of 96%
Analysis of results of huge segmental bone loss of tibia treated with Ilizarov external fixator: our experience in Indian population
Background: Orthopaedic surgeons face challenges in treating complex tibial fractures with bone loss due to complications like infection, repeat surgeries, and patient psychological burden. The Ilizarov external fixator approach offers better clinical and radiological results, addressing these issues. The purpose of this study was to examine the outcome of tibial segmental loss treated with the Iliazrov external fixator.
Methods: The study was done between January 2015 to December 2021. Itâs a prospective as well as retro-prospective study. The age group of 18-65 years was considered. Patients were monitored monthly, up to nine months post-surgery, or until bone union. Functional and bone outcomes of the patients were evaluated using ASAMI criteria, knee society score, and St. Pierre ankle scoring system.
Results: The study included 20 patients, all of them were male and had a mean age of 34.1±10.1. Bone union was achieved in all cases. After ilizarov application, the average bone defect was 82.6±42.9 mm. The final regeneration attained was 75.1±47.5 mm. The average limb length difference was 20.41±6.55 mm after achieving union. Out of 20 patients, 13 and 4 had good and fair ASAMI score, 1, 4, and 13 had fair, good, and excellent knee society score, and17 had fair St. Pierre score and 3 patients were lost to follow-up.
Conclusions: Ilizarov technique is an excellent way for treating complicated tibial fractures. The difficulties, challenges, and complications associated with Ilizarov external fixation are negligible compared to the significant difficulties associated with open techniques
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