Strings, Junctions and Stability

Identification of string junction states of pure SU(2) Seiberg-Witten theory as B-branes wrapped on a Calabi-Yau manifold in the geometric engineering limit is discussed. The wrapped branes are known to correspond to objects in the bounded derived category of coherent sheaves on the projective line \cp{1} in this limit. We identify the pronged strings with triangles in the underlying triangulated category using Pi-stability. The spiral strings in the weak coupling region are interpreted as certain projective resolutions of the invertible sheaves. We discuss transitions between the spiral strings and junctions using the grade introduced for Pi-stability through the central charges of the corresponding objects.Comment: 15 pages, LaTeX; references added. typos correcte

Chemical extraction and optimization of intracellular β-galactosidase production from the bacterium Arthrobacter oxydans using Box-Behnken design of response surface methodology

Present study demonstrated the isolation of most promising β-galactosidase producing bacterial strain SB from soil. Morphological, biochemical, and 16s rRNA sequence analysis identified the bacterial strain as Arthrobacter oxydans. Several chemicals, including SDS, Triton X-100, Tween 20, isoamyl alcohol, and toluene-acetone mixture, were applied for extraction of intracellular β-galactosidase from the bacterial strain Arthrobacter oxydans. Among these, Tween 20 was recorded to be most effective. Role of pH, temperature, and shaker speed on production of β-galactosidase was evaluated using Box-Behnken design of response surface methodology. According to Box-Behnken analysis, optimum production of β-galactosidase (21.38 U (mg–1 protein)) is predicted at pH 6.76, temperature 36.1 °C, and shaker speed 121.37 r.p.m. The parameters are validated with the nearest value

Analytical estimate of open-circuit voltage of a Schottky-barrier solar cell under high level injection

The open-circuit voltage developed across a Schottky-Barrier (SB) solar cell was theoretically modeled to estimate it under high level injection conditions. An Open-circuit voltage (Voc) of 0.709 V was obtained for specific metal/n-Si SB solar cell. A substantial increase of 42.6 % in Voc was noticed while comparing our result with that previously calculated in low level injection conditions. Four different metals suitable for making Schottky contact with n-Si were investigated and calculated the variation of Voc with different values of doping concentrations in the semiconductor. The effect of surface recombination velocities (SRV) of charge carriers on Voc was also estimated at such high level injections. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2789

Analytical estimate of open-circuit voltage of a Schottky-barrier solar cell under high level injection

The open-circuit voltage developed across a Schottky-Barrier (SB) solar cell was theoretically modeled to estimate it under high level injection conditions. An Open-circuit voltage (Voc) of 0.709 V was obtained for specific metal/n-Si SB solar cell. A substantial increase of 42.6 % in Voc was noticed while comparing our result with that previously calculated in low level injection conditions. Four different metals suitable for making Schottky contact with n-Si were investigated and calculated the variation of Voc with different values of doping concentrations in the semiconductor. The effect of surface recombination velocities (SRV) of charge carriers on Voc was also estimated at such high level injections. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2789

Diagnostic accuracy of the risk of malignancy index 1 compared to the more recent IOTA ADNEX model in discriminating benign from malignant adnexal masses: a multi-centric study

Background: Identification of the nature of an adnexal mass can ensure optimum management. Single parameters as well as diagnostic models using a combination of several parameters are in use. The International Ovarian Tumor Analysis (IOTA) consortium has developed and published the Assessment of Different NEoplasias in the adneXa (ADNEX) model, which differentiates between benign and malignant masses. Authors conducted this study with the aim of finding a cut off value for this model in the study population and comparing the diagnostic accuracy of this model to that of the risk of malignancy (RMI).Methods: Women with adnexal masses admitted to the 3 medical college affiliated hospitals for surgical management were included in this study. Appropriate investigations were done to calculate the RMI-I and ADNEX score for each participant. A cut off score for the ADNEX model was determined and diagnostic accuracy tests were done for comparison.Results: At a cut-off of 29 for the ADNEX model and 200 for RMI model the sensitivity was 75% and 77.8, specificity 100% and 80.6%; Positive Predictive Value (PPV) 100%and 60%; Negative Predictive Value (NPV) 91% and 90.6%; Positive Likelihood ratio of infinity and 4 and a negative Likelihood Ratio of 2.8 and 2.5 respectively.Conclusions: The ADNEX model rates higher than the RMI in almost all tests of diagnostic accuracy and can be used for triaging, framing a referral policy and prioritizing surgery

Comparative studies of the spectroscopic properties of nd3+: YAG nanocrystals transparent ceramic and single crystal

Detailed comparative spectroscopic studies of Nd3+ doped YAG nanocrystals, transparent ceramic and single crystal have been performed. Although most of the radiative spectral properties of Nd3+ are almost in good agreement between the three hosts, the non-radiative losses are significantly high in nanocrystals, which are attributed due to the presence of large amount of hydroxyl groups on the nanocrystals surface which deteriorates the quality of the material for laser applications. In addition, wavelength dependent scattering loss for the Nd3+ doped YAG nanocrystals is found significantly high compared to those of Nd3+ doped single crystal and ceramic. © 2012 Optical Society of America