2,118 research outputs found
BRST symmetries in SU(3) linear sigma model
We study the BRST symmetries in the SU(3) linear sigma model which is
constructed through introduction of a novel matrix for the Goldstone boson
fields satisfying geometrical constraints embedded in SU(2) subgroup. To treat
these constraints we exploit the improved Dirac quantization scheme. We also
discuss phenomenological aspacts in the mean field approach to this model.Comment: 17 pages, no figur
Isospin particle on with arbitrary number of supersymmetries
We study the supersymmetric quantum mechanics of an isospin particle in the
background of spherically symmetric Yang-Mills gauge field. We show that on
the number of supersymmetries can be made arbitrarily large for a
specific choice of the spherically symmetric SU(2) gauge field. However, the
symmetry algebra containing the supercharges becomes nonlinear if the number of
fermions is greater than two. We present the exact energy spectra and
eigenfunctions, which can be written as the product of monopole harmonics and a
certain isospin state. We also find that the supersymmetry is spontaneously
broken if the number of supersymmetries is even.Comment: 6 page
N=4 Supersymmetric Quantum Mechanics with Magnetic Monopole
We propose an N=4 supersymmetric quantum mechanics of a charged particle on a
sphere in the background of Dirac magnetic monopole and study the system using
the CP(1) model approach. We explicitly calculate the symmetry algebra taking
the operator ordering ambiguity into consideration. We find that it is given by
the superalgebra SU(1|2)x SU(2). We show that the Hamiltonian can be written in
terms of the Casimir invariant of SU(2). Using this relation and the lower
bound for angular momentm we obtain the energy spectrum. We then examine the
ground energy sector to find that the N=4 supersymmetry is spontaneously broken
to N=2 for certain values of the monopole charge.Comment: 7 page
Improving bread quality using Deinococcus geothermalis glycogen branching enzyme
Glycogen branching enzyme(GBE) catalyzes transglycosylation reaction producing α-1,6-glucosidic linkages by cleaving an α-1,4-glucosidic linkage. Deinococcus geothermalis GBE (DgGBE) has the unique activity to form a large number of short oligosaccharide side chains(degree of polymerization 3~5) from the reaction with amylose. To observe the influence of DgGBE on bread quaility, we added 100 unit of the enzyme per kg of the flour at the step of mixing dough. During the fermentation, DgGBE treated dough showed 50~100% larger volume than control. After baking, the total volume and the specific volume of DgGBE treated loaf showed about 10% larger than those of control. The baked breads were sliced to 2cm of depth and stored in 25 degrees celcius, and then the texture was evaluated by texture analyzer during storage time. Hardness and Chewiness of DgGBE treadted bread increased slowly to compared with those of the control. DgGBE treated bread showed a significant effect on antistaling.
1. Shupeng Wua, Yu Liu , Qiaojuan Yan , Zhengqiang Jiang (2014) Gene cloning, functional expression and characterisation of a novel glycogen branching enzyme from Rhizomucor miehei and its application in wheat breadmaking. Food Chemistry 159 (2014) 85-94
2. José Manuel Amigo , Arantxa del Olmo Alvarez , Merete MÞller Engelsen , Henrik Lundkvist , SÞren Balling Engelsen (2016) Staling of white bread crumb and effect of maltogenic α-amylases. Part 1 : Spatial distribution and kinetic modeling of hardness and resilience. Food Chemistry 208 (2016) 318-32
Intra-abdominal angiosarcoma developing in a capsule of a foreign body: report of a case with associated hemorrhagic diathesis
BACKGROUNDS: Angiosarcoma occurs very rarely in the gastrointestinal tract and can present great diagnostic difficulty, especially when it is associated with intraabdominal abscess or granulation tissue. CASE PRESENTATION: We report a case where the angiosarcoma was diagnosed after the occurrence of disseminated angiosarcoma and concurrent hemoperitoneum. The tumor developed in the fibrous capsule of a foreign body, which was possibly related to the previous appendectomy twenty years ago, and became a widely disseminated malignant neoplasm in the abdomen. After the operation, the patient's course was dominated by a fatal consumptive coagulapathy. Pathologic examination of the multiple intra-abdominal lesions showed the histological and immunohistological characteristics of the angiosarcoma. CONCLUSION: Even though angiosarcoma in the gastrointestinal tract is extremely rare, when dealing with intraabdominal abscess or the gastrointestinal bleeding in patients who have undergone surgery or radiation therapy in the past, the possibility of angiosarcoma should be considered. To make the definite diagnosis of angiosarcoma and to avoid the misdiagnosis of foreign body granuloma, thorough histological examination and immunohistochemical staining may be prerequisite
Development of screening method for the selection of mutants to improve the substrate specificity of Pyrococcus furiosus thermostable amylase
Pyrococcus furiosus thermostable amylase (PFTA) shows the activities of both a cyclodextrin hydrolyzing enzyme and an α-amylase. To improve the substrate affinity and hydrolyzing activity against cyclodextrins, the saturation mutagenesis on the residue of PFTA active site was carried out. After the mutagenesis, the new screening method was needed to select appropriate mutants efficiently from various mutants. Among the α-, ÎČ-, Îł-cyclodextrins, only ÎČ-cyclodextrin makes the complex with phenolphthalein. When added the ÎČ-cyclodextrin into phenolphthalein reagent, the color of the solution was changed red to colorless under alkaline condition. In this study, we developed screening method by using 24-well plate and phenolphthalein to compare the activity of PFTA mutants. Escherichia coli MC1061 was used as a host for the expression of various recombinant plasmids and cultured in 24-well plate with Luria-Bertani broth containing kanamycin. After cell lysis by heat treatment, each cell extracts were reacted with ÎČ-cyclodextrin at 70â. Reacted mixtures were put into 96-well plate with NaOH solution and then add the phenolphthalein reagent respectively. Lastly, the absorbance of the mixture was measured at 550 nm. The substrate specificity of PFTA mutants was compared from the difference of absorbance.
References
1. Sung-Jae Yang, Hee-Seob Lee, Cheon-Seok Park, Yong-Ro Kim, Tae-Wha Moon, and Kwan-Hwa Park. 2004. Enzymatic Analysis of an Amylolytic Enzyme from the Hyperthermophilic Archaeon Pyrococcus furiosus Reveals Its Novel Catalytic Properties as both an α-Amylase and a Cyclodextrin-Hydrolyzing Enzyme. APPL. ENVIRON. MICROBIOL. 70:5988-5995
2. Anuj Goel, Sanjay N. Nene. 1995. Modifications in the Phenolphthalein Method for Spectrophotometric Estimation of Beta Cyclodextrin. Starch/Starke. 47:399-40
Ultrahigh-efficiency solution-processed simplified small-molecule organic light-emitting diodes using universal host materials
Although solution processing of small-molecule organic light-emitting diodes (OLEDs) has been considered as a promising alternative to standard vacuum deposition requiring high material and processing cost, the devices have suffered from low luminous efficiency and difficulty of multilayer solution processing. Therefore, high efficiency should be achieved in simple-structured small-molecule OLEDs fabricated using a solution process. We report very efficient solution-processed simple-structured small-molecule OLEDs that use novel universal electron-transporting host materials based on tetraphenylsilane with pyridine moieties. These materials have wide band gaps, high triplet energy levels, and good solution processabilities; they provide balanced charge transport in a mixed-host emitting layer. Orange-red (similar to 97.5 cd/A, similar to 35.5% photons per electron), green (similar to 101.5 cd/A, similar to 29.0% photons per electron), and white (similar to 74.2 cd/A, similar to 28.5% photons per electron) phosphorescent OLEDs exhibited the highest recorded electroluminescent efficiencies of solution-processed OLEDs reported to date. We also demonstrate a solution-processed flexible solid-state lighting device as a potential application of our devices.
Optical spectroscopic investigation on the coupling of electronic and magnetic structure in multiferroic hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films
We investigated the effects of temperature and magnetic field on the
electronic structure of hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films
using optical spectroscopy. As the magnetic ordering of the system was
disturbed, a systematic change in the electronic structure was commonly
identified in this series. The optical absorption peak near 1.7 eV showed an
unexpectedly large shift of more than 150 meV from 300 K to 15 K, accompanied
by an anomaly of the shift at the Neel temperature. The magnetic field
dependent measurement clearly revealed a sizable shift of the corresponding
peak when a high magnetic field was applied. Our findings indicated strong
coupling between the magnetic ordering and the electronic structure in the
multiferroic hexagonal RMnO3 compounds.Comment: 16 pages including 4 figure
Higher dimensional cosmological model with a phantom field
We consider a higher dimensional gravity theory with a negative kinetic
energy scalar field and a cosmological constant. We find that the theory admits
an exact cosmological solution for the scale factor of our universe. It has the
feature that the universe undergoes a continuous transition from deceleration
to acceleration at some finite time. This transition time can be interpreted as
that of recent acceleration of our universe.Comment: 4 pages, 2 figures; References adde
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