Impact of hemodialysis on QT interval

Holter electrocardiographic recordings were performed for 24 hours in 20 patients with chronic renal failure on chronic hemodialysis to evaluate the effects of changes in serum calcium and potassium during hemodialysis period on the QT interval. Hemodialysis caused an increase in serum calcium from a predialysis value of 9.1 +/- 1.3 mg/dl to 11.5 +/- 1.2 mg/dl and a decrease in serum potassium from 5.6 +/- 1.4 mEg/L to 4.9 +/- 1.2 mEg/L. The Q-oTC interval shortened from a predialysis value of 0.240 +/- 0.0023 sec to 0.216 +/- 0.024 sec during the 5th hour of hemodialysis. The Q-eTc interval increased from a predialyse value of 0.391 +/- 0.030 sec to 0.412 +/- 0.024 sec during the 5th hour of hemodialysis. This shortening of Q-oTc interval was correlated with an increase in serum calcium and Q-eTc interval prolongation was correlated with a decrease in serum potassium. It was concluded that hemodialysis caused a lengthening of the Q-eTc interval and a shortening of the Q-oTc interval.     

On dielectric data analysis. Using the Monte Carlo method to obtainrelaxation time distribution and comparing non-linear spectral functionfits

In this paper, we present a technique for analyzing dielectric response data in the frequency domain, χ(ω)=ϵ(ω)-ϵ_∞ =ϵ'(ω)-ϵ_∞-iϵ(ω). We use a predistribution of relaxation times and reconstruct the original data by single Debye relaxations using a box constraint, least squares algorithm. The resulting relaxation times τ(D_i) and their amplitudes Δϵ_i,, yield the relaxation time spectrum, where i is equal or less than the number of data points. Two different predistributions of relaxation times are considered, log-uniform and adaptive. The adaptive predistribution is determined by the real part of the dielectric susceptibility χξ', and it allows for the increase of the number of effective relaxation times used in the fitting procedure. Furthermore, since the number of unknowns is limited to the number of data points, the Monte Carlo technique is introduced. In this way, the fitting procedure is repeated many times with randomly selected relaxation times, and the number of relaxation times treated in the procedure becomes continuous. The proposed method is tested for `ideal' and measured data. Finally, the method is compared with a nonlinear curve fitting by a spectral function which consists of three contributions, i.e. the Havriliak-Negami relaxation polarization, low frequency dispersion and de conductivity. It has been found that more information can be obtained from a particular data set if it is compared with a nonlinear curve fitting procedure. The method also can be used instead of the Kramers-Kronig transformation     

Nonsimilar boundary layers on the leeside of cones at incidence

It is known that the similarity equations for the leeward line of symmetry of a cone have no solutions for $\text{?1 < k}{}_2{}^1\text{< k < k}{}_1\text{1 < 0}$, where k is the incidence parameter of Moore, and $\text{k}{}_1{}^1\text{, k}{}_2{}^1$ depend on the external Mach number and enthalpy ratio. In this paper we present evidence that a leeside integration for such k terminates at a finite distance from the vertex in a singularity of the type analyzed by Stewartson and Simpson for entry flow in a curved pipe, and compare the theory with a representative numerical solution at $\text{k = ?}\text{1}\text{2}$. A possible interpretation of this singularity is that the boundary layers growing from the windward line of symmetry have collided, and support for this view is given by windward to leeward integrations for a range of values of k. For k such that the similarity equations have solutions, these are interpreted as limits of more general solutions.     

An Integration Algorithm for Constitutive Models with Two Intersecting Yield Surfaces

Abstract: In this paper, the constitutive models involving two active intersecting yield surfaces, such as Lade's model, are considered and a new integration algorithm is formulated. The formulation introduces a new class of the return mapping algorithm within the framework of the operator splitting methodology. The proposed algorithm is applicable to a general class of elastoplastic constitutive models exhibiting associative or nonassociative flow rule, arbitrary yield criteria and hardening laws. The algorithm can handle one or two active yield surfaces at a time. The development leads to a relatively simple, straightforward algorithm for updating the stresses at Gauss point.
Finally, the new algorithm is implemented in a generalized nonlinear finite element computer program incorporating Lade's model. The results of a number of boundary value problems are presented and compared with available experimental data and theoretical formulas. The comparisons indicate that incorporating the new class of return mapping algorithm gives reasonable solutions.     

Determination of antibiotic susceptibility and decarboxylase activity of coagulase‐negative Staphylococcus and Macrococcus caseolyticus strains isolated from fermented Turkish sausage (sucuk)

The aim of this research was to detect antibiotic susceptibility patterns and amino acid decarboxylase activity of 61 presumptive coagulase‐negative Staphylococcus (CNS) strains from the Turkish dry fermented sausage (sucuk). The presumptive CNS strains were identified at species levels as 21 S. saprophyticus, 16 S. epidermidis, 10 Macrococcus caseolyticus, 4 S. xylosus, 3 S. sciuri, 2 S. hominis, 2 S. warneri, 1 S. cohnii, 1 S. pasteuri, and 1 S. vitulinus by 16S rDNA sequence analysis. S. saprophyticus and S. epidermidis species were found highly resistant to antibiotics than other species. In addition, most of the CNS and M. caseolyticus strains showed multiple antibiotic resistance profiles. None of the CNS and M. caseolyticus strains did not decarboxylate histidine, lysine, or ornithine, but only three CNS strains produced tyramine from tyrosine. A 100% correlation was found between the presence of tdc gene and tyramine production in tyraminogenic strains.

Practical applications

Coagulase‐negative Staphylococcus (CNS) strains play an important role in production of traditional fermented sausages such as sucuk. In this study, S. saprophyticus and S. epidermidis were found the most common isolated CNS species from sucuk. Antibiotic resistance was detected widespread in CNS and M. caseolyticus strains. Most of the CNS strains were found resistant to clinically relevant antibiotics. Antibiotic resistance strains may be dangerous for consumer health. These strains can be a potential reservoir to spread of antibiotic resistance gene between staphylococci and other species of bacteria. In addition, biogenic amine production was not found widespread in CNS strains.     

A novel anti islanding detection method for grid connected fuel cell power generation systems

Renewable energy sources have been developed rapidly all around the world, and one of these green energy sources is hydrogen energy. The fuel cell systems have become prominent in renewable energy sources because of its minimal dimensions and energy conversion method. There have been developed, some applications, especially in domestic and automotive areas, and fuel cell systems are also have been started to use in grid connected systems. Fuel cell systems must have some electrical connection standards while they connected to an electrical grid. One of these electrical conditions and may be the most important one is unplanned islanding condition. Islanding is a very dangerous situation because it can damage to the fuel cell and related electrical systems and also working people have been at risk in islanding situation on the grid. In this study, a novel islanding detection method was introduced for grid connected fuel cell systems. 0.5 kW solid oxide fuel cell (SOFC) system used in developed experimental system and a novel anti islanding detection method was researched by using an effective method. The proposed method was also developed by using Matlab Simulink and its useful tools. The developed islanding detection method is robust, reliable and has a fast response time, according to present methods. The results confirm the suggested conditions, and it can be seen in this method, it can also be adapted easily to the grid connected fuel cell systems.     

Molecular methods for identification of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus using methionine biosynthesis and 16S rRNA genes

Yoghurt and starter culture producers are still searching strains of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus to produce healthier yogurt with longer shelf life, better texture, taste and quality. However, selective identification of Lb. delbrueckii subsp. bulgaricus and Strep. thermophilus from a mixed population using microbiological and biochemical methods is difficult, time consuming and may not be accurate. In this study, a quick, sensitive and accurate method is proposed to identify both Lb. delbrueckii subsp. bulgaricus and Strep. thermophilus using PCR. The method is comprised of two parts. In the first part, methionine biosynthesis genes, known to be present in both species were partially amplified by designed primers (cysmet2F and cysmet2R). Partial amplification of the methionine biosynthesis gene which gives 700 bp fragment resulted in selective identification of Lb. bulgaricus and Strep. thermophilus. All 16 Lb. bulgaricus and 6 Strep. thermophilus isolates assessed by this method gave the expected amplification. On the other hand, further analysis of other closely related species with the same primers have indicated that the same product was also amplified in two more lactobacilli namely, Lb. delbrueckii subsp. lactis and Lb. helveticus species. Thus, in the second part of the method, further differentiation of Lb. delbrueckii subsp. bulgaricus and Strep. thermophilus from each other and these species was achieved using restriction analysis of 16S rRNA gene with EcoRI.     

Styrenation of air-blown linseed oil by nitroxide-mediated radical polymerization

Styrenation of air-blown linseed oil by a nitroxide-mediated radical polymerization (NMRP) technique is described. In this technique, air-blown linseed oil bearing hydroperoxide groups was used as a macroinitiator in NMRP of styrene in the presence of 2,2′,6,6′-tetramethylpiperidinyl-1-oxy (TEMPO). The effects of various parameters, such as the amount of TEMPO and hydroperoxide groups, were investigated in terms of molecular weight and polydispersity. For comparison, a copolymer sample of air-blown linseed oil with styrene was also prepared in the absence of TEMPO. The film properties of all samples were determined according to the related standards and were compared with respect to surface protection. Samples prepared by the NMRP technique exhibited relatively narrow polydispersity and better film properties compared to those of the samples obtained by the conventional method.     

The effect of Er:YAG laser and bulk filled composite type on marginal adaptation of class II cavities: an SEM analysis study

Purpose: To evaluate the effect of cavity preparation method (Er:YAG laser or diamond bur) and bulk-filled composite material type on marginal adaptation mesial occlusal (MO) class II cavities. Materials and Methods: Two-surface box cavities (4-mm proximal depth and 5-mm occlusal width) were prepared on 60 human mandibular molar teeth. Cavities were prepared using Er:YAG laser or diamond burs in an air-turbine hand-piece. All cavities were applied Single Bond Universal dentin bonding agent. The cavities were further subdivided into three subgroups according to the restorative material used; two bulk-filled composites [Filtek Bulk Fill Posterior (3M ESPE) and SonicFill 2 (Kerr)] and one traditional composite material Filtek Ultimate Universal Restorative (3M ESPE). Restorations were evaluated using scanning electron microscopy at ×200 magnification for their adaptation to the approximal margins of the tooth. Results were analyzed using the two-way ANOVA and Tukey Post Hoc Test (p < 0.05). Results: A total of 900 SEM figures were obtained from all groups. Filtek Bulk Fill Posterior, SonicFill 2, and Filtek Ultimate Universal Restorative exhibited statistically similar gapped margins. However, the lowest scores of gapped margins were observed with SonicFill 2 (4.22%). Conclusions: Completely gap-free margins were not obtained with any of the tested materials. Bulk-fill composite materials showed similar marginal adapatation compared with standard composite. Marginal adaptation of Er:YAG laser prepared cavities was more irregular and had more gaps, but was statistically similar to diamond bur-prepared cavities.