INFLUENCE OF HIGH MICROWAVE DIELECTRIC-CONSTANTS ON THE LINESHAPE OF CONDUCTION-ELECTRON SPIN-RESONANCE

Some synthetic metals show in addition to good conductivity, high microwave dielectric constants. In this work, it is shown how conduction-electron spin resonance(CESR) lineshape can be affected by these high constants. The conditions for avoiding these effects in the CESR measurements are discussed as well as a method for extracting microwave dielectric constants from CESR lines. (C) 1995 Academic Press, Inc.

Application of pi Circuits for Simulation of Corona Effect in Transmission Lines

In this article, it is represented by state variables phase a transmission line which parameters are considered frequency independently and frequency dependent. Based on previous analyses, it is used the reasonable number of p circuits and the number of blocks composed by parallel resistor and inductor for reduction of numerical oscillations. It is analyzed the influence of the increase of the RL parallel blocks in the obtained results. The RL parallel blocks are used for inclusion of the frequency influence in the transmission line longitudinal parameter. It is a simple model that is been used by undergraduate students for simulation of traveling wave phenomena in transmission lines. Considering the model without frequency influence, it is included a representation of the corona effect. Some simulations are carried considering the corona effect and they are compared to the results without this phenomenon.

Analyses of the modifications in the pi circuits for inclusion of frequency influence in transmission line representation

In this article, it is represented by state variables phase a transmission line which parameters are considered frequency independently and frequency dependent. It is analyzed what is the reasonable number of pi circuits and the number of blocks composed by parallel resistor and inductor in parallel for reduction of numerical oscillations. It is simulated the numerical routine with and without the effect of frequency in the longitudinal parameters. Initially, it is used state variables and pi circuits representing the transmission line composing a linear system which is solved by numerical routines based on the trapezoidal rule. The effect of frequency on the line is synthesized by resistors and inductors in parallel and this representation is analyzed in details. It is described transmission lines and the frequency influence in these lines through the state variables.

Influence of the supply of reactive power in the calculation of the transfer capability

This paper presents some initial concepts for including reactive power in linear methods for computing Available Transfer Capability (ATC). It is proposed an approximation for the reactive power flows computation that uses the exact circle equations for the transmission line complex flow, and then it is determined the ATC using active power distribution factors. The transfer capability can be increased using the sensitivities of flow that show the best group of buses which can have their reactive power injection modified in order to remove the overload in the transmission lines. The results of the ATC computation and of the use of the sensitivities of flow are presented using the Cigré 32-bus system. © 2004 IEEE.

Sensitivity analysis for overload-relief in transmission lines using an implicitly coupled method (CRIC)

The restructuring of energy markets to provide free access to the networks and the consequent increase of the number of power transactions has been causing congestions in transmission systems. As consequence, the networks suffer overloads in a more frequent way. One parameter that has strong influence on transfer capability is the reactive power flow. A sensitivity analysis can be used to find the best solution to minimize the reactive power flows and relief, the overload in one transmission line. The proposed methodology consists on the computation of two sensitivities based on the use of the Lc matrix from CRIC (Constant Reactive Implicitly Coupled) power flow method, that provide a set of actions to reduce the reactive power flow and alleviate overloads in the lines: (a) sensitivity between reactive power flow in lines and reactive power injections in the buses, (b) sensitivity between reactive power flow in lines and transformer's taps. © 2006 IEEE.

Influence of endogenous and synthetic female sex hormones on human blood cells in vitro studied with comet assay

The comet assay has been conducted with numerous cell lines to assess in vitro genotoxicity. In order to use the comet assay as part of an in vitro test for evaluating genotoxicity, however, there are cell-specific factors that need to be better understood. In this present study we have evaluated some factors that may impact upon the DNA damage detected in whole blood (WB) cells and lymphocytes (ILs). Experiments were conducted comparing responses of both cells, and investigating the effects of the female hormonal cycle, and oral contraceptive (OC) use on DNA damage detection in the in vitro comet assay, at three sampling time. No significant differences were detected in the basal levels of DNA damage detected in ILs and WB cells from women OC users and non-users and from men. Basal DNA damage in ILs was unaffected by gender and stage of the menstrual cycle or the stage of the treatment schedule. Our results also indicated that the H2O2 induces DNA damage in human lymphocytes independently of gender, low-dose OC use and hormonal fluctuation. However, data showed that in 3rd sampling of menstrual cycle, lymphocytes were more resistant to H2O2-induced DNA damage than those from OC users and men. © 2007 Elsevier Ltd. All rights reserved.

Rumen microbial diversity under influence of a polyclonal antibody preparation against lactate-producing and proteolytic bacteria in cows fed different energy sources

Nine ruminally cannulated cows fed different energy sources were used to evaluate an avianderived polyclonal antibody preparation against specific ruminal bacteria and monensin on microbial community diversity. The experimental design was three Latin squares 3 x 3 distinguished by the main energy source in the diet [dry-ground corn grain, high moisture corn silage or citrus pulp]. Inside each Latin square, animals received one of the feed additives per period [control, monensin or polyclonal antibody preparation]. Each period lasted 21 days where 20 were used for treatments adaptation and the last one for sampling collection. Microbial diversity was evaluated by protozoa counts and denaturing gradient gel electrophoresis. Polyclonal antibodies plus citrus pulp (CiPu) addition in the diet resulted in an increase of relative counting of Isotricha protozoa that indicates a possible effect on this ruminal ciliate population. In general lines, in the present experiment, it was not possible to assign that there was a pattern in the structures of amplification of Bacteria and Archaea communities of the ruminal content. Oral passive immunization is a technology that arises as an effective alternative for feed additive production. Further research is still necessary to better understand its mechanisms of action.

Identification of transmission line parameters from temporal measurements of currents and voltages in their terminals: Influence oh the length line

The objective of this paper is to show a methodology to estimate transmission line parameters. The method is applied in a single-phase transmission line using the method of least squares. In this method the longitudinal and transversal parameters of the line are obtained as a function of a set of measurements of currents and voltages (as well as their derivatives with respect to time) at the terminals of the line during the occurrence of a short-circuit phase-ground near the load. The method is based on the assumption that a transmission line can be represented by a single circuit π. The results show that the precision of the method depends on the length of the line, where it has a better performance for short lines and medium length. © 2012 IEEE.

Reproductive tract development and puberty in two lines of Nellore heifers selected for postweaning weight

The objective was to evaluate reproductive tract development (ovary and uterus) and onset of puberty in two lines of Nellore heifers (Bos indicus) selected for postweaning weight. A total of 123 heifers, including 46 from the control Nellore line (NeC) and 77 from the selection Nellore line (NeS) were used. Every 18 to 21 days from 12 to 24 months of age, average ovarian area (OVA), endometrial thickness (ETh), and diameter of the largest follicle in each ovary were evaluated (using transrectal ultrasonography), and body weight, hip height, and body condition score were measured. There were no differences between NeS and NeC heifers for ETh or OVA (P < 0.05). Genetic selection for higher postweaning weight had no negative influence on the onset of puberty, with 52% and 48% of NeC and NeS heifers, respectively, pubertal at 24 months of age (P = 0.49). Heifers that reached puberty at the end of the study were heavier (NeC, 296.9 vs. 276.7 kg; NeS, 343.5 vs. 327.9 kg; P < 0.01) and younger (NeC, 23.4 vs. 24.2 mo; NeS, 22.7 vs. 24.0 months; P < 0.01) than those that did not. Furthermore, heifers that were heavier at weaning reached puberty earlier. Pubertal heifers had a greater OVA (4.15 vs. 3.14 cm2; P < 0.01) and ETh (12.15 vs. 9.93 mm; P < 0.01) than nonpubertal heifers. Taken together, OVA and ETh had positive effects (P < 0.01) on the onset of puberty and were suitable indicator traits of heifer sexual precocity in pasture management systems. However, selection for weight did not alter ovarian or endometrial development, or manifestation of puberty at 24 months of age. Among the growth traits studied, weaning weight and weight at puberty had significant positive effects on manifestation of first estrus. © 2013 Elsevier Inc.

Rumen microbial diversity under influence of a polyclonal antibody preparation against lactate-producing and proteolytic bacteria in cows fed different energy sources

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

An in vitro study showing the three-dimensional microenvironment influence over the behavior of head and neck squamous cell carcinoma

Objectives: The Head and Neck Squamous Cell Carcinoma (HNSCC) ranks sixth worldwide. The mechanisms of growth, invasion and metastasis of this pathology are extensively studied and generally related to specific variations in signaling pathways like the PI3K-Akt; however most of these competent studies have been performed bidimensionally, which may hide important questions. This study sought to analyze the influence of the microenvironment upon the behavior of HNSCC. Study Design: The status of pAkt, NF-kappa B and Cyclin D1 proteins was accessed through immunofluorescence and western blot methods in HNSCC cell lines originating from tongue, pharynx and metastatic lymph node when submitted to a three-dimensional culture model utilizing a matrix system. A bidimensional culture model (monolayer) was used as control. Results: The HNSCC cell lines cultured three-dimensionally exhibited a growth pattern characterized by small isolated islands, different from the control group. When the three-dimensional model was applied, two of the studied cell lines showed the same expression pattern as the bidimensional model regarding nuclear or cytoplasmatic localization, as well as reduction of all protein levels; however, the cell line originated from tongue, which specially has the epidermal growth factor receptor constitutively activated, demonstrated nuclear translocation of pAkt and also an increase in the levels of Cyclin D1. Conclusions: The results suggest the influence of the microenvironment upon the behavior of HNSCC cells due to the changed expression of proteins related to tumor growth and cellular invasion. Furthermore, intrinsically genetic conditions also played important roles over the cells, despite the culture model employed.

Influence of nutritional variables and obesity on health and metabolism

Influence of nutritional variables and obesity on health and metabolism Obesity is a recurring theme in current scientific literature. This can easily be explained by its exponential increase in all layers of society. The popularity of this subject has also given rise to associated questions, which have achieved greater prominence in health-related publications. In order to assess what has been studied in the field of obesity and nutrition, an overview of all articles published on these subjects in some of the main Brazilian scientific journals over the past two years was performed. Among the subthemes selected for this study, those related to childhood obesity attracted attention due to their greater frequency. These were subdivided into: prevalence, intrauterine and breastfeeding influences that may lead to the development of this condition, impact on quality of life, cardiovascular system and metabolism, and possible prevention strategies. Furthermore, issues related to obesity in adults were explored, such as risk factors and new strategies for prevention, with special attention given to the many studies evaluating different aspects of bariatric surgery. Finally, the subject of malnutrition and the impact of the deficiency of specific micronutrients such as selenium, vitamin D, and vitamin B12 were assessed. Based on the results, it was possible to assess the actual importance of obesity and nutrition in health maintenance, and also the several lines of research regarding these issues. Thus, it is essential to create new methods, which must be quick and efficient, to update health professionals involved in the treatment of obesity.

In vitro cytotoxicity of Selol-loaded magnetic nanocapsules against neoplastic cell lines under AC magnetic field activation

The goals of this study are to evaluate in vitro compatibility of magnetic nanomaterials and their therapeutic potential against cancer cells. Highly stable ionic magnetic fluid sample (maghemite, gamma-Fe2O3) and Selol were incorporated into polymeric nanocapsules by nanoprecipitation method. The cytotoxic effect of Selol-loaded magnetic nanocapsules was assessed on murine melanoma (B16-F10) and oral squamous cell carcinoma (OSCC) cell lines following AC magnetic field application. The influence of different nanocapsules on cell viability was investigated by colorimetric MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. In the absence of AC magnetic field Selol-loaded magnetic nanocapsules, containing 100 mu g/mL Selol plus 5 x 10(12) particle/mL, showed antitumoral activity of about 50% on B16-F10 melanoma cells while OSCC carcinoma cells demonstrated drug resistance at all concentrations of Selol and magnetic fluid (range of 100-500 mu g/mL Selol and 5 x 10(12) -2.5 x 10(13) particle/mL). On the other hand, under AC applied fields (1 MHz and 40 Oe amplitude) B16-F10 cell viability was reduced down to 40.5% (+/- 3.33) at the highest concentration of nanoencapsulated Selol. The major effect, however, was observed on OSCC cells since the cell viability drops down to about 33.3% (+/- 0.38) under application of AC magnetic field. These findings clearly indicate that the Selol-loaded magnetic nanocapsules present different toxic effects on neoplastic cell lines. Further, the cytotoxic effect was maximized under AC magnetic field application on OSCC, which emphasizes the effectiveness of the magnetohyperthermia approach. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3680541]

Influence of electric fields over the nucleation ratio of the lithium-potassium sulfate and its pedagogical value

[EN]This paper presents our research about nucleation and its dependency with external conditions, as well as the internal characteristics of the solution itself. Among the research lines of our group, we has been studying the influence of electric fields over two different but related compounds: Lithium-Potassium Sulfate and Lithium-Amonium Sulfate, which both of them show a variation on the nucleation ratio when an electric field is applied during the crystal growth. Moreover, in this paper will be explained a laboratory protocol to teach universitary Science students the nucleation process itself and how it depends on external applied conditions, e.g. electric fields.

Elf magnetic field influence on ION Channels studied by Patch Clamp Technique: exposure set up and "Whole Cell" measurements on Potassium currents

The aim of this thesis was to study the effects of extremely low frequency (ELF) electromagnetic magnetic fields on potassium currents in neural cell lines ( Neuroblastoma SK-N-BE ), using the whole-cell Patch Clamp technique. Such technique is a sophisticated tool capable to investigate the electrophysiological activity at a single cell, and even at single channel level. The total potassium ion currents through the cell membrane was measured while exposing the cells to a combination of static (DC) and alternate (AC) magnetic fields according to the prediction of the so-called ‘ Ion Resonance Hypothesis ’. For this purpose we have designed and fabricated a magnetic field exposure system reaching a good compromise between magnetic field homogeneity and accessibility to the biological sample under the microscope. The magnetic field exposure system consists of three large orthogonal pairs of square coils surrounding the patch clamp set up and connected to the signal generation unit, able to generate different combinations of static and/or alternate magnetic fields. Such system was characterized in term of field distribution and uniformity through computation and direct field measurements. No statistically significant changes in the potassium ion currents through cell membrane were reveled when the cells were exposed to AC/DC magnetic field combination according to the afore mentioned ‘Ion Resonance Hypothesis’.