Finite field-energy of a point charge in QED

We consider a simple nonlinear (quartic in the fields) gauge-invariant modification of classical electrodynamics, which possesses a regularizing ability sufficient to make the field energy of a point charge finite. The model is exactly solved in the class of static central-symmetric electric fields. Collation with quantum electrodynamics (QED) results in the total field energy about twice the electron mass. The proof of the finiteness of the field energy is extended to include any polynomial selfinteraction, thereby the one that stems from the truncated expansion of the Euler-Heisenberg local Lagrangian in QED in powers of the field strenth

Coffee consumption has no acute effects on glucose metabolism in healthy men : a randomized crossover clinical trial

We investigate the effect of coffee (caffeinated and decaffeinated) on glucose effectiveness and insulin sensitivity using the stable isotope minimal model protocol with oral glucose administration in healthy men

A study on corrosion resistance of ISO 5832-1 austenitic stainless steel used as orthopedic implant

The ISO 5832-1 austenitic stainless steel used as biomaterial is largely applied in the area of orthopedics, especially in the manufacture of implants, such as temporary or permanent replacement of bone structures. The objective of this study was to evaluate the localized corrosion resistance of the ISO 5832-1 stainless steel used in orthopedic implants by electrochemical tests in two different solutions. The results of this study are of great interest to evaluate the corrosion of metallic implants that can result in the release of corrosion products into bodily fluids causing possible adverse biological reactions. The determination of the chemical elements in the composition of the ISO 5832-1 stainless steel was performed by neutron activation analysis (NAA). The samples for electrochemical tests were grinded with silicon carbide paper up to #4000 finishing, followed by mechanical polishing with diamond paste. The open circuit potential measurements and anodic polarization curves were obtained in solution of 0.90 wt. % of NaCl and of simulated body fluid (SBF). The results indicated that the ISO 5832-1 stainless steel presented a high resistance to crevice corrosion in simulated body fluid solution but high susceptibility to this form of corrosion in the chloride solution. &nbsp

Study of ph effect on AZ31 magnesium alloy corrosion for using in temporary implants

Currently, magnesium alloys are gaining great interest for medical applications due to their degrading properties in the human body ensuring a great biocompatibility. These alloys also provide profitable mechanical properties due similarities with human bone.  However, a difficulty in applying these materials in the biomaterials industries is the corrosion prior to cell healing. The effect of the chemical composition of Mg alloys on their corrosion behavior is well known. In this study, samples of AZ31 magnesium alloy were cut into chips for elemental chemical analysis by neutron activation analysis (NAA). Concentrations of the elements As, La, Mg, Mn, Na, Sb and Zn were determined in the AZ31 alloy. Visualization tests of agar corrosion development in various media, of 0.90% sodium chloride solution (mass), phosphate buffer saline (PBS) and simulated body fluid (SBF) were performed. Visualizations of the effect of agar gel corrosion revealed pH variation during the corrosion process due to the released into the cathode. The highest released of hydroxyl ions occurred in NaCl solution compared to PBS and SBF solutions indicating that NaCl solution was much more aggressive to the alloy compared to the others

Climate diagnostics of three major drought events in the Amazon and illustrations of their seasonal precipitation predictions

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Effects of Enteral Fluid Therapy in Continuous Flow Administered by Nasogastric Tube in Buffalo Calves

To investigate the employment of enteral fluid therapy in continuous flow administered by a nasogastric tube in buffalo calves; toassesstheeffectsof a hypotonic and an isotonic electrolyte solutionon: vital functions, blood count and serum andurinary biochemistry profile of buffalo calves. Seven buffalo calves, clinically healthy, were submitted to two treatments. The solutions were administered in continuous flow through a nasogastric tube at a dose of 15 mL/kg/hr for 12 hours. The serum biochemistry profile showed an increase in chloride concentration, decrease in serumurea and osmolarity. In urine, anincrease in sodium and chloride concentrations and a decrease in calcium, creatinine and urea were observed. Enteral fluid therapy in continuous flow proved to beeasy to use and effective in maintaining volemia and concentration of electrolytes in buffalo calves

IFN-γ Production Depends on IL-12 and IL-18 Combined Action and Mediates Host Resistance to Dengue Virus Infection in a Nitric Oxide-Dependent Manner

Dengue is a mosquito-borne disease caused by one of four serotypes of Dengue virus (DENV-1–4). Severe dengue infection in humans is characterized by thrombocytopenia, increased vascular permeability, hemorrhage and shock. However, there is little information about host response to DENV infection. Here, mechanisms accounting for IFN-γ production and effector function during dengue disease were investigated in a murine model of DENV-2 infection. IFN-γ expression was greatly increased after infection of mice and its production was preceded by increase in IL-12 and IL-18 levels. In IFN-γ−/− mice, DENV-2-associated lethality, viral loads, thrombocytopenia, hemoconcentration, and liver injury were enhanced, when compared with wild type-infected mice. IL-12p40−/− and IL-18−/− infected-mice showed decreased IFN-γ production, which was accompanied by increased disease severity, higher viral loads and enhanced lethality. Blockade of IL-18 in infected IL-12p40−/− mice resulted in complete inhibition of IFN-γ production, greater DENV-2 replication, and enhanced disease manifestation, resembling the response seen in DENV-2-infected IFN-γ−/− mice. Reduced IFN-γ production was associated with diminished Nitric Oxide-synthase 2 (NOS2) expression and NOS2−/− mice had elevated lethality, more severe disease evolution and increased viral load after DENV-2 infection. Therefore, IL-12/IL-18-induced IFN-γ production and consequent NOS2 induction are of major importance to host resistance against DENV infection