Further on the current algebra of WZNW models at and away from criticality

We comment on the off-critical perturbations of WZNW models by a mass term as well as by another descendent operator, when we can compare the results with further algebra obtained from the Dirac quantization of the model, in such a way that a more general class of models be included. We discover, in both cases, hidden Kac-Moody algebras obeyed by some currents in the off-critical case, which in several cases are enough to completely fix the correlation functions.

Influence of polymerization on the synthesis of SrTiO3: Part II. Particle and agglomerate morphologies

Morphologies of SrTiO3 particles and agglomerates synthesized by the traditional Pechini route and by the polymer precipitation route were characterized by the nitrogen adsorption/desorption technique and by transmission electron microscopy (TEM). A cluster structure of nanometric particles forming large agglomerates which are broken during pressing followed by cluster rearrangement was observed. The mean particle size is larger for SrTiO3 obtained by the Pechini route and is related to the precursor thermal decomposition and particle growth during calcination. The particle growth is controlled by neck growth among particles and further motion of the particle boundary. © 1995.

Preparation, characterization and electrochemical studies of dinuclear copper(II) complexes with pseudohalides and bidentate amines on platinum electrode in acetonitrile

The complexes: [Cu(N 3) 2(N,N-diEten)] 2, [Cu(N 3) 2(tmeen)] 2, [Cu(N 3)(NCO)(N,N-diEten)] 2, [Cu(N 3) 2(N,N′-diMeen)] 2 and [Cu(N 3)(NCO)(tmeen)] 2 were prepared, characterized and their electrochemical behavior was investigated by cyclic voltammetry and controlled potential electrolysis. Cyclic voltammograms for all complexes studied are similar and exhibit one pair of current peaks in the range of -0.65 to +0.0 V. The number of electrons obtained from controlled potential electrolysis at ca. -0.55 V for all compounds was 1.8 ≤ n ≤ 2.1, indicating that both copper(II) metallic centres in the molecule were reduced to copper (I). Comparing the peak potential values for these complexes one can observe that the redox process corresponding to copper(II)/copper(I) couple is slightly influenced by the σ-basicity of the ligands. © 1997 Soc. Bras. Química.

Adsorption and structure of copper(II) complexes on a silica gel surface chemically modified with 2-aminothiazole

The isotherms of adsorption of CuX2 (X=Cl-, Br-, ClO- 4) by silica gel chemically modified with 2-aminothiazole were studied in acetone and EtOH solutions, at 25°C. The 2-aminothiazole molecule, covalently bond to the silica gel surface, adsorbs CuX2 from solvent by forming a surface complex. At low loading, the electronic and E.S.R. spectral parameters indicate that the Cu2+ complexes have a distorted tetragonal symmetry. The d-d eletronic transition spectra show that for ClO- 4 complex, the peak of absorption do not change for any degree of metal loading whilst for Cl- and Br- complexes, the peak maxima shift to higher energy with lower metal loading. © Elsevier Science Ltd.

Application of HPLC-NMR coupling using C30 phase in the separation and identification of flavonoids of taxonomic relevance

The on-line separation and identification of two important taxonomic markers for plant species of the Paepalanthus genus, the flavonoids 6-methoxykaempferol-3-O-β-D-glucopyranoside and 6-methoxykaempferol-3-O-β-D-6″(p-coumaroyl)glucopyranoside, has been performed with an HPLC-NMR coupling using C30 phase. 1D spectra have been recorded in the stopped-flow mode for the two predominant chromatographic peaks. This is the first application of HPLC-NMR coupling using C30 phase to a taxonomic problem. The technique drastically reduces the required amount of sampling for structure determination. © Springer-Verlag 2000.

Synthesis and spectroscopic characterization of new metal(II) complexes with methionine sulfoxide

Methionine sulfoxide complexes of iron(II) and copper(II) were synthesized and characterized by chemical and spectroscopic techniques. Elemental and atomic absorption analyses fit the compositions K2[Fe(metSO) 2]SO4 · H2O and [Cu(metSO)2] · H2O. Electronic absorption spectra of the complexes are typical of octahedral geometries. Infrared spectroscopy suggests coordination of the ligand to the metal through the carboxylate and sulfoxide groups. An EPR spectrum of the Cu(II) complex indicates tetragonal distortion of its octahedral symmetry. 57Fe Mössbauer parameters are also consistent with octahedral stereochemistry for the iron(II) complex. The complexes are very soluble in water.

Preconcentration and determination of mercury(II) at a chemically modified electrode containing 3-(2-thioimidazolyl)propyl silica gel

A mercury-sensitive chemically modified graphite paste electrode was constructed by incorporating modified silica gel into a conventional graphite paste electrode. The functional group attached to the (3-chloropropyl) silica gel surface was 2-mercaptoimidazole, giving a new product denoted by 3-(2-thioimidazolyl)propyl silica gel, which is able to complex mercury ions. Mercury was chemically adsorbed on the modified graphite paste electrode containing 3-(2-thioimidazolyl)propyl silica (TIPSG GPE) by immersion in a Hg(II) solution, and the resultant surface was characterized by cyclic and differential pulse anodic stripping voltammetry. One cathodic peak at 0.1 V and other anodic peak at 0.34 V were observed on scanning the potential from -0.1 to 0.8 V (0.01 M KNO3; ν = 2.0 mV s-1 νs. Ag/AgCl). The anodic peak at 0.34 V show an excellent sensitivity for Hg(II) ions in the presence of several foreign ions. A calibration graph covering the concentration range from 0.02 to 2 mg L-1 was obtained. The detection limit was estimated to be 5 μg L-1. The precision for six determinations of 0.05 and 0.26 mg L-1 Hg(II) was 3.0 and 2.5% (relative standard deviation), respectively. The method can be used to determine the concentration of mercury(II) in natural waters contaminated by this metal. 2005 © The Japan Society for Analytical Chemistry.

One-loop conformal invariance of the type II pure spinor superstring in a curved background

We compute the one-loop beta functions for the Type II superstring using the pure spinor formalism in a generic supergravity background. It is known that the classical pure spinor BRST symmetry puts the background fields on-shell. In this paper we show that the one-loop beta functions vanish as a consequence of the classical BRST symmetry of the action. © SISSA 2007.

Proposal of a new technique for bile duct reconstruction after iatrogenic injury. Study in dogs and review of the literature

Purpose: Interposition of a jejunal tube between the common bile duct and duodenum. Methods: Five adult mongrel dogs of both sexes, weighing on average 22.3 kg (18 to 26.5 kg), were used. Obstructive jaundice was induced by ligation of the distal common bile duct. After one week, a 2.5-cm long jejunal tube was fabricated from a segment of the loop removed 15 cm from the Treitz angle and interposed between the common bile duct and duodenum. Results: The animals presented good clinical evolution and no complications were observed. After 6 weeks, complete integration was noted between the bile duct mucosa, tube and duodenum and a significant reduction in total bilirubin and alkaline phosphatase was observed when compared to the values obtained one week after ligation of the common bile duct. Conclusion: The jejunal tube interposed between the dilated bile duct and duodenum showed good anatomic integration and reduced total bilirubin and alkaline phosphatase levels in the animals studied.

Occurrence, extension, and severity of gingival margin alterations after orthodontic treatment.

To assess the occurrence, extension, and severity of gingival margin alterations in a sample of youth after orthodontic treatment. Records from 209 Caucasian adolescents (118 female and 91 male) before and after orthodontic treatment were selected. Patients presented a mean age at the beginning of orthodontic treatment of 11.20 ± 1.86 years and a final mean age of 14.72 ± 1.83 years. Class I and II patients with mandibular incisors and canines that were completely erupted and with spacing or crowding not exceeding 4 mm were evaluated. The presence of gingival recession on the labial surface of the mandibular anterior teeth was evaluated in intraoral photographs and casts made before and after treatment. The proportion of patients with gingival recession after treatment was statistically higher than at the beginning (P<.001). After orthodontic treatment, gingival recession was not present in any of the teeth for 63.6% of the patients; in 29.2% of the patients, recession was present in at least 1 tooth. In terms of severity, the majority of affected teeth (47%) presented gingival recession less than 2 mm and in 2% more than 4 mm. It may be concluded that alterations in the gingival margin, especially gingival recession, occur in patients after orthodontic therapy, but the extent and severity of this finding are low. COPYRIGHT © 2007 BY QUINTESSENCE PUBLISHING CO, INC.

Hydrothermal synthesis and crystal structure of a copper(ii) coordination polymer with bridging dicarboxylate and diamine ligands

This work reports on the synthesis of a copper(II) coordination compound with 4,4-oxibis(benzoate) (obb) and trans-1,2- bis(4-pyridyl)ethene (bpe) ligands. The complex was characterized by single-crystal X-ray diffraction, which showed a 3D polymeric structure. Each copper center is surrounded by four oxygen atoms at the basal plane and one nitrogen atom and one copper atom at the axial positions, revealing a distorted octahedral geometry. Four carboxylic groups bridge two copper atoms, forming a cage-like structure, with the distance between the metallic centers being 2.656(1)Å. 2008 © The Japan Society for Analytical Chemistry.

Crystal and molecular structure of dinuclear palladium(II) complex containing nitrogen and phosphorus donor ligands, [Pd2(N3)4(PPh3)2(μ-ted)]

The dinuclear azido-palladium(II) complex [Pd2(N3)4(PPh3)2(μ-ted)], where PPh3 = triphenylphosphine and ted = triethylenediamine, was synthesized and characterized by single-crystal X-ray diffraction. The title compound was crystallized in a triclinic system, space group P1 with a = 11.5875(2)Å, b = 13.0817(3)Å, c = 15.2618(3)Å, α = 93.306(2)°, β =110.040(1)°, γ = 98.486(1)°, V = 2134.95(8)Å3, Z = 2. Each Pd(II) center displays a distorted squareplanar coordination environment formed by two N atoms from two trans terminally coordinated azido groups, one P atom from the phosphine and one N atom from the bridging ted ligand. 2008 © The Japan Society for Analytical Chemistry.

A comparative analysis of FBD, PQ and CPT current decompositions - Part II: Three-phase four-wire systems

This paper investigates the major similarities and discrepancies among three important current decompositions proposed for the interpretation of unbalanced and/or non linear three-phase four-wire power circuits. The considered approaches were the so-called FBD Theory, the pq-Theory and the CPT. Although the methods are based on different concepts, the results obtained under ideal conditions (sinusoidal and balanced signals) are very similar. The main differences appear in the presence of unbalanced and non linear load conditions. It will be demonstrated and discussed how the choice of the voltage referential and the return conductor impedance can influence in the resulting current components, as well as, the way of interpreting a power circuit with return conductor. Under linear unbalanced conditions, both FBD and pq-Theory suggest that the some current components contain a third-order harmonic. Besides, neither pq-Theory nor FBD method are able to provide accurate information for reactive current under unbalanced and distorted conditions, what can be done by means of the CPT. © 2009 IEEE.

Measurement of angular correlations of jets at s=1.96 TeV and determination of the strong coupling at high momentum transfers

We present a measurement of the average value of a new observable at hadron colliders that is sensitive to QCD dynamics and to the strong coupling constant, while being only weakly sensitive to parton distribution functions. The observable measures the angular correlations of jets and is defined as the number of neighboring jets above a given transverse momentum threshold which accompany a given jet within a given distance δR in the plane of rapidity and azimuthal angle. The ensemble average over all jets in an inclusive jet sample is measured and the results are presented as a function of transverse momentum of the inclusive jets, in different regions of δR and for different transverse momentum requirements for the neighboring jets. The measurement is based on a data set corresponding to an integrated luminosity of 0.7 fb -1 collected with the D0 detector at the Fermilab Tevatron Collider in pp- collisions at s=1.96 TeV. The results are well described by a perturbative QCD calculation in next-to-leading order in the strong coupling constant, corrected for non-perturbative effects. From these results, we extract the strong coupling and test the QCD predictions for its running over a range of momentum transfers of 50-400 GeV. © 2012 Elsevier B.V.

Finding best urban routes based on analyses of high level and IOPT Petri net models

This paper presents a tool that combines two kinds of Petri Net analyses to set the fastest routes to one vehicle in a bounded area of traffic urban. The first analysis consists of the discovery of possible routes in a state space generated from an IOPT Petri net model given the initial marking as the vehicle position. The second analysis receives the routes found in the first analysis and calculates the state equations at incidence matrix created from the High Level Petri net model to define the fastest route for each vehicle that arrive in the roads. It was considered the exchange of information between vehicle and infrastructure (V2I) to get the position and speed of all vehicles and support the analyses. With the results obtained we conclude that is possible optimizing the urban traffic flow if this tool is applied to all vehicles in a bounded urban traffic. © 2012 IEEE.