Crystallization and preliminary X-ray diffraction analysis of a glutathione S-transferase from Xylella fastidiosa

Glutathione S-transferases (GSTs) form a group of multifunctional isoenzymes that catalyze the glutathione-dependent conjugation and reduction reactions involved in the cellular detoxification of xenobiotic and endobiotic compounds. GST from Xylella fastidiosa (xfGST) was overexpressed in Escherichia coli and purified by conventional affinity chromatography. In this study, the crystallization and preliminary X-ray analysis of xfGST is described. The purified protein was crystallized by the vapour-diffusion method, producing crystals that belonged to the triclinic space group P1. The unit-cell parameters were a = 47.73, b = 87.73, c = 90.74 angstrom, alpha = 63.45, beta = 80.66, gamma = 94.55 degrees. xfGST crystals diffracted to 2.23 angstrom resolution on a rotating-anode X-ray source.

Crystallization and preliminary X-ray diffraction analysis of human IL-22 bound to its soluble decoy receptor IL-22BP

Interleukin-22 (IL-22) is a pleiotropic cytokine that is involved in inflammatory responses. Human IL-22 was incubated with its soluble decoy receptor IL-22BP (IL-22 binding protein) and the IL-22 -IL-22BP complex was crystallized in hanging drops using the vapour-diffusion method. Suitable crystals were obtained from polyethylene glycol solutions and diffraction data were collected to 2.75 angstrom resolution. The crystal belonged to the tetragonal space group P41, with unit-cell parameters a = b = 67.9, c = 172.5 angstrom, and contained two IL-22-IL- 22BP complexes per asymmetric unit.

Crystallization and preliminary X-ray diffraction analysis of recombinant chlorocatechol 1,2-dioxygenase from Pseudomonas putida

Chlorocatechol 1,2-dioxygenase from the Gram-negative bacterium Pseudomonas putida (Pp 1,2-CCD) is considered to be an important biotechnological tool owing to its ability to process a broad spectrum of organic pollutants. In the current work, the crystallization, crystallographic characterization and phasing of the recombinant Pp 1,2-CCD enzyme are described. Reddish-brown crystals were obtained in the presence of polyethylene glycol and magnesium acetate by utilizing the vapour-diffusion technique in sitting drops. Crystal dehydration was the key step in obtaining data sets, which were collected on the D03B-MX2 beamline at the CNPEM/MCT - LNLS using a MAR CCD detector. Pp 1,2-CCD crystals belonged to space group P6(1)22 and the crystallographic structure of Pp 1,2-CCD has been solved by the MR-SAD technique using Fe atoms as scattering centres and the coordinates of 3-chlorocatechol 1,2-dioxygenase from Rhodococcus opacus (PDB entry 2boy) as the search model. The initial model, which contains three molecules in the asymmetric unit, has been refined to 3.4 A resolution.

X-ray diffraction data of tibolone Delta(4) isomer (isotibolone)

Tibolone is used for hormone reposition of postmenopause women and isotibolone is considered the major degradation product of tibolone. Isotibolone can also be present in tibolone API raw materials due to some inadequate synthesis. Its presence is then necessary to be identified and quantified in the quality control of both API and drug products. In this work we present the indexing of an isotibolone X-ray diffraction pattern measured with synchrotron light (lambda=1.2407 angstrom) in the transmission mode. The characterization of the isotibolone sample by IR spectroscopy, elemental analysis, and thermal analysis are also presented. The isotibolone crystallographic data are a=6.8066 angstrom, b=20.7350 angstrom, c=6.4489 angstrom, beta=76.428 degrees, V=884.75 angstrom(3), and space group P2(1), rho(o)= 1.187 g cm(-3), Z=2. (C) 2009 International Centre for Diffraction Data. [DOI: 10.1154/1.3257612]

A hybrid material assembled by anthocyanins from acai fruit intercalated between niobium lamellar oxide

Organic-inorganic hybrid materials can be prepared dispersing organic species into well-defined inorganic nanoblocks. This paper describes the immobilization of natural dyes from the extract of the Brazilian acai-fruit into two types of layered hexaniobate precursors derived from H(2)K(2)Nb(6)O(17): (i) colloidal dispersion of niobate exfoliated nanoparticles and (ii) niobate pre-intercalated with tetraethylammonium cations (TEA(+)). The restacking of exfoliated particles in the presence of acai anthocyanins promotes their intercalation and produces stacked layers showing large basal spacing (ca. 50 angstrom). The TEA(+) pre-intercalated niobate provides particles with lower content of dye species than the exfoliated precursor but with higher degree of organization and regularity according to X-ray diffraction data and images obtained by electron microscopies. Vibrational (FTIR and Raman) and (13)C NMR spectroscopies indicate the presence of flavylium cations in the hybrid materials and spectral profiles characteristic of glycosylated anthocyanidins. According to thermal analysis results, the purplish hybrids materials are more stable than the free acai-dyes. One hybrid sample was heated under air up to 170 degrees C and maintained at this temperature for 240 min. No weight loss events were observed and the sample retained its original color, indicating that the intercalation of anthocyanin into hexaniobate increases its thermal stability. Considering the structural, chemical, optical and thermal properties of the synthesized hybrid materials, they might be good candidates to be investigated for future specialized applications.

Weight loss associated with exercise training restores ventilatory efficiency in obese children

The purpose of this study was to test the hypothesis that in obese children: 1) Ventilatory efficiency (VentE) is decreased during graded exercise; and 2) Weight loss through diet alone (D) improves VentE, and 3) diet associated with exercise training (DET) leads to greater improvement in VentE than by D. Thirty-eight obese children (10 +/- 0.2 years; BMI > 95(th) percentile) were randomly divided into two Study groups: D (n=17; BMI = 30 +/- 1 kg/m(2)) and DET (n = 21; 28 +/- 1 kg/m(2)). Ten lean children were included in a control group (10 +/- 0.3 years; 17 +/- 0.5 kg/m(2)). All children performed maximal treadmill testing with respiratory gas analysis (breath-by-breath) to determine the ventilatory anaerobic threshold (VAT) and peak oxygen consumption (VO(2) peak). VentE was determined by the VE/VCO(2) method at VAT. Obese children showed lower VO(2) peak and lower VentE than controls (p < 0.05). After interventions, all obese children reduced body weight (p < 0.05). D group did not improve in terms of VO(2) peak or VentE (p > 0.05). In contrast, the DET group showed increased VO(2) peak (p = 0.01) and improved VentE(Delta VE/VCO(2) = -6.1 +/- 0.9; p = 0.01). VentE is decreased in obese children, where weight loss by means of DET, but not D alone, improves VentE and cardiorespiratory fitness during graded exercise.

Prevalence, magnitude, and methods of rapid weight loss among judo competitors

ARTIOLI, G. G., B. GUALANO, E. FRANCHINI, F. B. SCAGLIUSI, M. TAKESIAN, M. FUCHS, and A. H. LANCHA. Prevalence, Magnitude, and Methods of Rapid Weight Loss among Judo Competitors. Med. Sci. Sports Exerc., Vol. 42, No. 3, pp. 436-442, 2010. Purpose: To identify the prevalence, magnitude, and methods of rapid weight loss among judo competitors. Methods: Athletes (607 males and 215 females; age = 19.3 +/- 5.3 yr, weight = 70 +/- 7.5 kg, height = 170.6 +/- 9.8 cm) completed a previously validated questionnaire developed to evaluate rapid weight loss in judo athletes, which provides a score. The higher the score obtained, the more aggressive the weight loss behaviors. Data were analyzed using descriptive statistics and frequency analyses. Mean scores obtained in the questionnaire were used to compare specific groups of athletes using, when appropriate, Mann-Whitney U-test or general linear model one-way ANOVA followed by Tamhane post hoc test. Results: Eighty-six percent of athletes reported that have already lost weight to compete. When heavyweights are excluded, this percentage rises to 89%. Most athletes reported reductions of up to 5% of body weight (mean +/- SD: 2.5 +/- 2.3%). The most weight ever lost was 2%-5%, whereas a great part of athletes reported reductions of 5%-10% (mean +/- SD: 6 +/- 4%). The number of reductions underwent in a season was 3 +/- 5. The reductions usually occurred within 7 +/- 7 d. Athletes began cutting weight at 12.6 +/- 6.1 yr. No significant differences were found in the score obtained by male versus female athletes as well as by athletes from different weight classes. Elite athletes scored significantly higher in the questionnaire than nonelite. Athletes who began cutting weight earlier also scored higher than those who began later. Conclusions: Rapid weight loss is highly prevalent in judo competitors. The level of aggressiveness in weight management behaviors seems to not be influenced by the gender or by the weight class, but it seems to be influenced by competitive level and by the age at which athletes began cutting weight.

Rapid weight loss followed by recovery time does not affect judo-related performance

In this study, we investigated the effects of rapid weight loss followed by a 4-h recovery on judo-related performance. Seven weight-cycler athletes were assigned to a weight loss group (5% body weight reduction by self-selected regime) and seven non-weight-cyclers to a control group (no weight reduction). Body composition, performance, glucose, and lactate were assessed before and after weight reduction (5-7 days apart; control group kept weight stable). The weight loss group had 4 h to re-feed and rehydrate after the weigh-in. Food intake was recorded during the weight loss period and recovery after the weigh-in. Performance was evaluated through a specific judo exercise, followed by a 5-min judo combat and by three bouts of the Wingate test. Both groups significantly improved performance after the weight loss period. No interaction effects were observed. The energy and macronutrient intake of the weight loss group were significantly lower than for the control group. The weight loss group consumed large amounts of food and carbohydrate during the 4-h recovery period. No changes were observed in lactate concentration, but a significant decrease in glucose during rest was observed in the weight loss group. In conclusion, rapid weight loss did not affect judo-related performance in experienced weight-cyclers when the athletes had 4 h to recover. These results should not be extrapolated to inexperienced weight-cyclers.

Thermal expansion of the V(5)Si(3) and T(2) phases of the V-Si-B system investigated by high-temperature X-ray diffraction

The thermal expansion anisotropy of the V(5)Si(3) and T(2)-phase of the V-Si-B system were determined by high-temperature X-ray diffraction from 298 to 1273 K. Alloys with nominal compositions V(62.5)Si(37.5) (V5Si3 phase) and V(63)Si(12)B(25) (T(2)-phase) were prepared from high-purity materials through arc-melting followed by heat-treatment at 1873 K by 24 h, under argon atmosphere. The V(5)Si(3) phase exhibits thermal expansion anisotropy equals to 1.3, with thermal expansion coefficients along the a and c-axis equal to 9.3 x 10(-6) K(-1) and 11.7 x 10(-6) K(-1), respectively. Similarly, the thermal expansion anisotropy value of the T(2)-phase is 0.9 with thermal expansion coefficients equal to 8.8 x 10(-6) K(-1) and 8.3 x 10(-6) K(-1) along the, a and c-axis respectively. Compared to other isostructural silicides of the 5:3 type and the Ti(5)Si(3) phase, the V(5)Si(3) phase presents lower thermal expansion anisotropy. The T(2)-phase present in the V-Si-B system exhibits low thermal expansion anisotropy, as the T(2)-phase of the Mo-Si-B, Nb-Si-B and W-Si-B systems. (C) 2009 Elsevier Ltd. All rights reserved.

Theoretical and Experimental Study of Polarization Dependent Loss in a Optical Recirculating Loop

An experimental study of the Polarization Dependent Loss (PDL) is performed in an Optical Recirculating Loop (RCL). The RCL enables to simulate the transmission through various optical links using just one optical fiber spool, one in line amplifier, some optical filters and devices in a low cost manner. The total amount of PDL in a Recirculating loop, due to its statistical nature, is different of the simple sum of each element of the recirculating loop because of the alignment variation of the PDL elements with time, depending on the environmental conditions such as fiber stress and temperature. In this paper theoretical studies are also performed using formalism of Jones and Mueller matrices in order to represent the different optical elements in the recirculating loop. The PDL must be correctly characterized in order to evaluate properly the impact on the performance of next generation DWDM systems. Theoretical and experimental results comparison shows that a depolarization of 7% occurs in the experimental setup, probably by the optical amplifier due to the depolarized nature of the amplified spontaneous emission.

Loss minimization by the predictor-corrector modified barrier approach

This paper presents a new approach, predictor-corrector modified barrier approach (PCMBA), to minimize the active losses in power system planning studies. In the PCMBA, the inequality constraints are transformed into equalities by introducing positive auxiliary variables. which are perturbed by the barrier parameter, and treated by the modified barrier method. The first-order necessary conditions of the Lagrangian function are solved by predictor-corrector Newton`s method. The perturbation of the auxiliary variables results in an expansion of the feasible set of the original problem, reaching the limits of the inequality constraints. The feasibility of the proposed approach is demonstrated using various IEEE test systems and a realistic power system of 2256-bus corresponding to the Brazilian South-Southeastern interconnected system. The results show that the utilization of the predictor-corrector method with the pure modified barrier approach accelerates the convergence of the problem in terms of the number of iterations and computational time. (C) 2008 Elsevier B.V. All rights reserved.

Transmission loss allocation based on optimal power flow and sensitivity analysis

This paper presents a new approach to the transmission loss allocation problem in a deregulated system. This approach belongs to the set of incremental methods. It treats all the constraints of the network, i.e. control, state and functional constraints. The approach is based on the perturbation of optimum theorem. From a given optimal operating point obtained by the optimal power flow the loads are perturbed and a new optimal operating point that satisfies the constraints is determined by the sensibility analysis. This solution is used to obtain the allocation coefficients of the losses for the generators and loads of the network. Numerical results show the proposed approach in comparison to other methods obtained with well-known transmission networks, IEEE 14-bus. Other test emphasizes the importance of considering the operational constraints of the network. And finally the approach is applied to an actual Brazilian equivalent network composed of 787 buses, and it is compared with the technique used nowadays by the Brazilian Control Center. (c) 2007 Elsevier Ltd. All rights reserved.

Diffraction gratings fabricated in DLC thin films

This work presents the fabrication of two-dimensional diffraction gratings in diamond-like carbon (DLC) thin films, with applications in computer-generated holography and micro optics. In order to achieve high diffraction efficiency and to have a very simple manufacturing process, the device is designed to modulate only the phase of an incoming coherent monochromatic laser beam (632.8 nm, HeNe laser). This modulation is obtained by implementing a binary microrelief in the DLC film, responsible for generating a localized optical path difference of half a wavelength. This microrelief is obtained by anisotropic reactive ion etching of the DLC surface in an oxygen based plasma. The DLC layer was grown by reactive magnetron sputtering, using a methane-based plasma chemistry. AFM measurements show a low-level surface roughness of less than 1% of the operation wavelength, and optical characterization shows a good quality of the reconstructed diffraction patterns. (C) 2010 Elsevier B.V. All rights reserved.

Friction loss correction in flowing well discharge tests

Artesian confined aquifers do not need pumping energy, and water from the aquifer flows naturally at the wellhead. This study proposes correcting the method for analyzing flowing well tests presented by Jacob and Lohman (1952) by considering the head losses due to friction in the well casing. The application of the proposed correction allowed the determination of a transmissivity (T = 411 m(2)/d) and storage coefficient (S = 3 x 10(-4)) which appear to be representative for the confined Guarani Aquifer in the study area. Ignoring the correction due to head losses in the well casing, the error in transmissivity evaluation is about 18%. For the storage coefficient the error is of 5 orders of magnitude, resulting in physically unacceptable value. The effect of the proposed correction on the calculated radius of the cone of depression and corresponding well interference is also discussed.

X-ray diffraction characterisation of expanded austenite and ferrite in plasma nitrided stainless steels

The S phase, known as expanded austenite, is formed on the surfaces of austenitic stainless steels that are nitrided under low temperature plasma. A similar phase was observed for nitrided ferritic stainless steels and was designed as expanded ferrite or ferritic S phase. The authors treated samples of austenitic AISI 304L and AISI 316L and ferritic AISI 409 stainless steels by plasma nitriding at different temperatures and then studied the structural, morphological, chemical and corrosion characteristics of the modified layers by X-ray diffraction, scanning electron microscopy/energy dispersive spectroscopy and electrochemical tests. For both austenitic AISI 304L and AISI 316L stainless steels, the results showed that a hard S phase layer was formed on the surfaces, promoting an anodic polarisation curve displacement to higher current density values that depend on the plasma nitriding temperature. A layer having a high amount of nitrogen was formed on the ferritic AISI 409 stainless steel. X-ray diffraction measurements indicated high strain states for the modified layers formed on the three stainless steels, being more pronounced for the ferritic S phase.