Local order and magnetic field effects on the electronic properties of disordered binary alloys in the quantum site percolation limit

Electronic properties of disordered binary alloys are studied via the calculation of the average Density of States (DOS) in two and three dimensions. We propose a new approximate scheme that allows for the inclusion of local order effects in finite geometries and extrapolates the behavior of infinite systems following finite-size scaling ideas. We particularly investigate the limit of the Quantum Site Percolation regime described by a tight-binding Hamiltonian. This limit was chosen to probe the role of short range order (SRO) properties under extreme conditions. The method is numerically highly efficient and asymptotically exact in important limits, predicting the correct DOS structure as a function of the SRO parameters. Magnetic field effects can also be included in our model to study the interplay of local order and the shifted quantum interference driven by the field. The average DOS is highly sensitive to changes in the SRO properties and striking effects are observed when a magnetic field is applied near the segregated regime. The new effects observed are twofold: there is a reduction of the band width and the formation of a gap in the middle of the band, both as a consequence of destructive interference of electronic paths and the loss of coherence for particular values of the magnetic field. The above phenomena are periodic in the magnetic flux. For other limits that imply strong localization, the magnetic field produces minor changes in the structure of the average DOS. © World Scientific Publishing Company.

Effect of recasting procedure upon corrosion behavior and metallic ion release of Co-Cr-Mo dental alloy in physiological

Recasting process influence upon corrosion behavior of Co-Cr-Mo dental alloy in simulated physiological serum has been investigated using chemical and electrochemical techniques. Recast Co-Cr-Mo alloy by induction (IND) or by blowtorch (FLAME) has exhibited similar dendritic structures. Both IND and FLAME alloys have presented good corrosion resistance in physiological serum. Passivation process provides this corrosion resistance. Codissolution makes this process difficult. Passive films, formed on these alloys, have been analyzed as a dual layer consisting of an inner barrier and an outer porous layer. Passive film protective characteristics are higher in FLAME than in IND alloy. On this last alloy, the passive film is more porous due to a higher Codissolution. ©Carl Hanser Verlag, München.

Potentiation of epidural lidocaine by co-administering tramadol by either intramuscular or epidural route in cats

This study investigated the analgesic and systemic effects of intramuscular (IM) versus epidural (EP) administration of tramadol as an adjunct to EP injection of lidocaine in cats. Six healthy, domestic, shorthair female cats underwent general anesthesia. A prospective, randomized, crossover trial was then conducted with each cat receiving the following 3 treatments: EP injection of 2% lidocaine [LEP; 3.0 mg/kg body weight (BW)]; EP injection of a combination of lidocaine and 5% tramadol (LTEP; 3.0 and 2.0 mg/kg BW, respectively); or EP injection of lidocaine and IM injection of tramadol (LEPTIM; 3.0 and 2.0 mg/kg BW, respectively). Systemic effects, spread and duration of analgesia, behavior, and motor blockade were determined before treatment and at predetermined intervals afterwards. The duration of analgesia was 120 ± 31 min for LTEP, 71 ± 17 min for LEPTIM, and 53 ± 6 min for LEP (P < 0.05; mean ± SD). The cranial spread of analgesia obtained with LTEP was similar to that with LEP or LEPTIM, extending to dermatomic region T13-L1. Complete motor blockade was similar for the 3 treatments. It was concluded that tramadol produces similar side effects in cats after either EP or IM administration. Our findings indicate that EP and IM tramadol (2 mg/kg BW) with EP lidocaine produce satisfactory analgesia in cats. As an adjunct to lidocaine, EP tramadol provides a longer duration of analgesia than IM administration. The adverse effects produced by EP and IM administration of tramadol were not different. Further studies are needed to determine whether EP administration of tramadol could play a role in managing postoperative pain in cats when co-administered with lidocaine after painful surgical procedures.

Effects of a mixed vector-scalar kink-like potential for spinless particles in two-dimensional space time

The intrinsically relativistic problem of spinless particles subject to a general mixing of vector and scalar kink- like potentials (similar to tanh gamma x) is investigated. The problem is mapped into the exactly solvable Sturm - Liouville problem with the Rosen - Morse potential and exact bounded solutions for particles and antiparticles are found. The behavior of the spectrum is discussed in some detail. An apparent paradox concerning the uncertainty principle is solved by recurring to the concept of effective Compton wavelength.

SU(3) breaking and annihilation effects in the η and η′ masses

The mass splitting of the pseudoscalar mesons η and η′ is approached by taking into account the SU(3)-flavor symmetry breaking and annihilation effects. An extended version of the Schwinger sum rule and a mixing angle equal to -19.51° are obtained.

Oxidation of amino acids by chlorpromazine cation radical and co-catalysis by chlorpromazine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Co-simulation tools for networked control systems: revision and utilization

Networked control systems (NCSs) are distributed control systems in which the sensors, actuators, and controllers are physically separated and connected through an industrial network. The main challenge related to the development of NCSs is the degenerative effects caused by the inclusion of this communication network in the closed loop control. In order to mitigate these effects, co-simulation tools for NCS have been developed to study the network influence in the NCS. This paper presents a revision about co-simulation tools for NCS and the application of two of these tools for the design and evaluation of NCSs. The TrueTime and Jitterbug tools were used together to evaluate the main configuration parameter that affects the performance of CAN-based NCS and to verify the NCS quality of control under various timing conditions including different transmission period of messages and network delays. Therefore, the simulation results led to the conclusion that despite the transmission period of messages is the most significant factor among the analyzed in the design of NCS, its influence is related to the kind of system with greater effects in NCSs with fast dynamics.

Sonochemical effects on ZnO particles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Produção de etanol utilizando cascas de banana e de laranja por co-fermentação de Zymomonas mobilis e Pichia stipitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Terpinen-4-ol: estudo do efeito sinérgico/aditivo, adesão em co-cultura e alteração dos fatores de virulência sobre Candida spp

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of different cryopreservation methods on post-thaw culture conditions of in vitro produced bovine embryos

The aim of this work was to evaluate the effect of cryopreservation protocols on subsequent development of in vitro produced bovine embryos under different culture conditions. Expanded in vitro produced blastocysts (n = 600) harvested on days 7-9 were submitted to controlled freezing [slow freezing group: 10% ethylene glycol (EG) for 10 min and 1.2 degrees C/min cryopreservation]; quick-freezing [rapid freezing group: 10% EG for 10 min, 20% EG + 20% glycerol (Gly) for 30 s]; or vitrification [vitrification group: 10% EG for 10 min, 25% EG + 25% Gly for 30 s] protocols. Control group embryos were not exposed to cryoprotectant or cryopreservation protocols and the hatching rate was evaluated on day 12 post-insemination. In order to evaluate development, frozen-thawed embryos were subjected to granulosa cell co-culture in TCM199 or SOFaa for 4 days. Data were analyzed by PROC MIXED model using SAS Systems for Windows (R). Values were significant at p < 0.05. The hatching rate of the control group was 46.09%. In embryos cultured in TCM199, slow freezing and vitrification group hatching rates were 44.65 +/- 5.94% and 9.43 +/- 6.77%, respectively. In embryos cultured in SOFaa, slow freezing and vitrification groups showed hatching rates of 11.65 +/- 3.37 and 8.67 +/- 4.47%, respectively. In contrast, the rapid freezing group embryos did not hatch, regardless of culture medium. The slow freezing group showed higher hatching rates than other cryopreservation groups. Under such conditions, controlled freezing (1.2 degrees C/min) can be an alternative to cryopreservation of in vitro produced bovine embryos.

Effects of selective bile duct ligation on liver parenchyma in young animals: histologic and molecular evaluations

Background/Purpose: The mechanisms of increased collagen production and liver parenchyma fibrosis are poorly understood. These phenomena are observed mainly in children with biliary obstruction (BO), and in a great number of patients, the evolution to biliary cirrhosis and hepatic failure leads to the need for liver transplantation before adolescence. However, pediatric liver transplantation presents with biliary complications in 20% to 30% of cases in the postoperative period. Intra-or extrahepatic stenosis of bile ducts is frequent and may lead to secondary biliary cirrhosis and the need for retransplantation. It is unknown whether biliary stenosis involving isolated segments or lobes may affect the adjacent nonobstructed lobes by paracrine or endocrine means, leading to fibrosis in this parenchyma. Therefore, the present study aimed to create an experimental model of selective biliary duct ligation in young animals with a subsequent evaluation of the histologic and molecular alterations in liver parenchyma of the obstructed and nonobstructed lobes. Methods: After a pilot study to standardize the surgical procedures, weaning rats underwent ligation of the bile ducts of the median, left lateral, and caudate liver lobes. The bile duct of the right lateral lobe was kept intact. To avoid intrahepatic biliary duct collaterals neoformation, the parenchymal connection between the right lateral and median lobes was clamped. The animals were divided into groups according to the time of death: 1, 2, 3, 4, and 8 weeks after surgical procedure. After death, the median and left lateral lobes (with BO) and the right lateral lobe (without BO [NBO]) were harvested separately. A group of 8 healthy nonoperated on animals served as controls. Liver tissues were subjected to histologic evaluation and quantification of the ductular proliferation and of the portal fibrosis. The expressions of smooth muscle alpha-actin (alpha-SMA), desmin, and transforming growth factor beta 1 genes were studied by molecular analyses (semiquantitative reverse transcriptase-polymerase chain reaction and real-time polymerase chain reaction, a quantitative method). Results: Histologic analyses revealed the occurrence of ductular proliferation and collagen formation in the portal spaces of both BO and NBO lobes. These phenomena were observed later in NBO than BO. Bile duct density significantly increased 1 week after duct ligation; it decreased after 2 and 3 weeks and then increased again after 4 and 8 weeks in both BO and NBO lobes. The portal space collagen area increased after 2 weeks in both BO and NBO lobes. After 3 weeks, collagen deposition in BO was even higher, and in NBO, the collagen area started decreasing after 2 weeks. Molecular analyses revealed increased expression of the alpha-SMA gene in both BO and NBO lobes. The semiquantitative and quantitative methods showed concordant results. Conclusions: The ligation of a duct responsible for biliary drainage of the liver lobe promoted alterations in the parenchyma and in the adjacent nonobstructed parenchyma by paracrine and/or endocrine means. This was supported by histologic findings and increased expression of alpha-SMA, a protein related to hepatic fibrogenesis. (C) 2012 Elsevier Inc. All rights reserved.

Environmental effects in kelvin force microscopy of modified diamond surfaces

We have explored the effects of atmospheric environment on Kelvin force microscopy (KFM) measurements of potential difference between different regions of test polycrystalline diamond surfaces. The diamond films were deposited by microwave plasma-assisted chemical vapor deposition, which naturally produces hydrogen terminations on the surface of the films formed. Selected regions were patterned by electron-beam lithography and chemical terminations of oxygen or fluorine were created by exposure to an oxygen or fluorine plasma source. For KFM imaging, the samples were mounted in a hood with a constant flow of helium gas. Successive images were taken over a 5-h period showing the effect of the environment on KFM imaging. We conclude that the helium flow removes water molecules adsorbed on the surface of the samples, resulting in differences in surface potential between adjacent regions. The degree of water removal is different for surfaces with different terminations. The results highlight the importance of taking into account the atmospheric environment when carrying out KFM analysis. (C) 2012 Wiley Periodicals, Inc.

Positive effects of zinc supplementation on growth, GH, IGF1, and IGFBP3 in eutrophic children

Zinc is an essential micronutrient for growth and development. Its deficiency causes growth retardation in children and adolescents. The present study analyzes the effect of zinc on growth hormone (GH) secretion, insulin-like growth factor 1 (IGF1), and insulin-like growth factor-binding protein 3 (IGFBP3) in normal children before puberty. Thirty normal children were studied, 15 boys and 15 girls, aged 6-9 years. They were orally supplemented with 5 mg Zn/day for 3 months and 0.06537 mg Zn/kg body weight was injected before and after oral supplementation. Dietary intake and anthropometric measurements were assessed at baseline and end of study. Plasma GH levels increased during intravenous zinc administration and IGF1 and IGFBP3 increased after oral zinc supplementation. There was a positive correlation between the areas under the curves of GH and zinc after oral supplementation. Zinc supplementation was possibly effective in improving the body zinc status of the children, secretory levels of IGF1 and IGFBP3, GH potentialization, and height.

Correlating phase and microstructure development versus dielectric properties in La3+ and Er3+ co-doped Bi4Ti3O12 ferroelectric ceramics

Bi3.25La0.75-xErxTi3O12 and Bi3.25La0.75Ti3-xErxO12-delta ceramics were prepared and studied in this work in terms of dopant-induced phase and microstructure development as well as dielectric response. The results show that introduction of Er3+ tends to reduce the materials' sintering temperature and average grain size. Moreover, it was noted that in these systems the substitution site of this dopant is controlled by valence state and ionic radii mismatch effects. In particular, even when a nominal substitution of Ti4+ is conceived, here it is found that Er3+ also incorporates at the (Bi,La)(3+) sites. These and other interesting concluding remarks from this work, including Er3+ tolerance, were possible only after comparing, especially, the X-ray diffraction results and the intrinsic ferroelectric characteristics extracted from the dielectric measurements. (C) 2011 Elsevier B.V. All rights reserved.