Main Effective Parameters Research Articles

Assessment of combined antiandrogenic effects of binary parabens mixtures in a yeast-based reporter assay

To date, toxicological studies of endocrine disrupting chemicals (EDCs) have typically focused on single chemical exposures and associated effects. However, exposure to EDCs mixtures in the environment is common. Antiandrogens represent a group of EDCs, which draw increasing attention due to their resultant demasculinization and sexual disruption of aquatic organisms. Although there are a number of in vivo and in vitro studies investigating the combined effects of antiandrogen mixtures, these studies are mainly on selected model compounds such as flutamide, procymidone, and vinclozolin. The aim of the present study is to investigate the combined antiandrogenic effects of parabens, which are widely used antiandrogens in industrial and domestic commodities. A yeast-based human androgen receptor (hAR) assay (YAS) was applied to assess the antiandrogenic activities of n-propylparaben (nPrP), iso-propylparaben (iPrP), methylparaben (MeP), and 4-n-pentylphenol (PeP), as well as the binary mixtures of nPrP with each of the other three antiandrogens. All of the four compounds could exhibit antiandrogenic activity via the hAR. A linear interaction model was applied to quantitatively analyze the interaction between nPrP and each of the other three antiandrogens. The isoboles method was modified to show the variation of combined effects as the concentrations of mixed antiandrogens were changed. Graphs were constructed to show isoeffective curves of three binary mixtures based on the fitted linear interaction model and to evaluate the interaction of the mixed antiandrogens (synergism or antagonism). The combined effect of equimolar combinations of the three mixtures was also considered with the nonlinear isoboles method. The main effect parameters and interaction effect parameters in the linear interaction models of the three mixtures were different from zero. The results showed that any two antiandrogens in their binary mixtures tended to exert equal antiandrogenic activity in the linear concentration ranges. The antiandrogenicity of the binary mixture and the concentration of nPrP were fitted to a sigmoidal model if the concentrations of the other antiandrogens (iPrP, MeP, and PeP) in the mixture were lower than the AR saturation concentrations. Some concave isoboles above the additivity line appeared in all the three mixtures. There were some synergistic effects of the binary mixture of nPrP and MeP at low concentrations in the linear concentration ranges. Interesting, when the antiandrogens concentrations approached the saturation, the interaction between chemicals were antagonistic for all the three mixtures tested. When the toxicity of the three mixtures was assessed using nonlinear isoboles, only antagonism was observed for equimolar combinations of nPrP and iPrP as the concentrations were increased from the no-observed-effect-concentration (NOEC) to effective concentration of 80%. In addition, the interactions were changed from synergistic to antagonistic as effective concentrations were increased in the equimolar combinations of nPrP and MeP, as well as nPrP and PeP. The combined effects of three binary antiandrogens mixtures in the linear ranges were successfully evaluated by curve fitting and isoboles. The combined effects of specific binary mixtures varied depending on the concentrations of the chemicals in the mixtures. At low concentrations in the linear concentration ranges, there was synergistic interaction existing in the binary mixture of nPrP and MeP. The interaction tended to be antagonistic as the antiandrogens approached saturation concentrations in mixtures of nPrP with each of the other three antiandrogens. The synergistic interaction was also found in the equimolar combinations of nPrP and MeP, as well as nPrP and PeP, at low concentrations with another method of nonlinear isoboles. The mixture activities of binary antiandrogens had a tendency towards antagonism at high concentrations and synergism at low concentrations.

Predictive Statistical Model for Indoor Manganese Airborne Particles Affected by Psychrometric Parameters

Commonly, there are varieties of indoor airborne particles in the foundry factories. One of the main particle with emphasize on health effect on exposed human is manganese airborne particle. The current study considered correlation between indoor psychrometric parameters and manganese concentration in the workplace. Overall, fifty samples were collected by filter based on OSHA ID-121method in the workplaces. SPSS V.20 was used to find a predictive model using linear regression model. The mean personal exposure to manganese was 1.626 mg/m . The mean measured psychrometric parameters for dry temperature, relative 3 humidity and air velocity were 29°C, 52% and 1.2m/s, respectively. The correlations between personal exposures and indoor air parameters measurements showed a high significant relationship between personal exposure, dry temperature and wind speed in the factory (P< 0.05). This study concluded that controlling dry temperature and air velocity is the main effective parameters on airborne manganese concentration in the workplaces and decreased the personal exposure.

A new core–shell Ti3AlC2/Cu composite powder prepared by electroless plating method

The core–shell Cu-coated Ti3AlC2 composite powders were fabricated by using the electroless plating method, the Ti3AlC2 particles were coated by a uniform and dense copper shell with about 500–900nm thickness, and the influence of main effective parameters such as the content of reducing agent, concentration of Ti3AlC2 particles and the temperature of the plating solution on the uniformity of copper layer was investigated. The surface morphologies and chemical composition of the initial Ti3AlC2 powder and Cu-coated Ti3AlC2 powder were also characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results showed that the plating rate increased as increasing the content of the reducing agent, and the optimal reductant concentration was determined as 10–15ml/l. The mechanical and electrical properties of Ti3AlC2/Cu composites reinforced by copper coated Ti3AlC2 particles were much better than that reinforced by the pristine Ti3AlC2.

A hybrid solar desalination system of air humidification dehumidification and water flashing evaporation: A comparison among different configurations

This work deals with comparison among different configurations of the hybrid solar powered desalination system. A hybrid desalination system based on air humidification and dehumidification–single stage flashing (HDH–SSF) has been investigated for different configurations. The main effective arrangement parameters and operating conditions that give minimum water cost and maximum performance are shown. The characteristics of this system in different layouts and working conditions are studied in order to evaluate four main parameters; water cost, water production, thermal performance and environmental impacts. Four configurations are analyzed for HDH–SSF desalination system including the conventional system, which is formed by HDH and SSF unit in standalone layout in addition to three different configurations of hybrid and standalone layouts. The present study covered one year of system operation, in summer and winter for typical climate conditions of the Tanta, Egypt. The most important parameters for the proposed system performance were the heat recovery by mixing tank and air preheating. The hybrid HDH–SSF with solar air heater resulted as the best economical configuration with daily water production up to 96l in August and a production cost of 12.53$/m3. The efficiency of the system is measured by the gained output ratio (GOR) with day time. The standalone HDH–SSF with heat recovery resulted as the best performing one with gained output ratio (GOR) about 10.2.

Technical characteristic analysis of wind energy conversion systems for sustainable development

Wind energy as a clean, environmentally friendly and cost effective renewable energy resource, is taken into consideration by many developed and developing countries as a promising means to provide electrical energy. In feasibility study stage of the wind energy systems, the sustainability analysis is one of the main issues that can assure the investors and stockholders to invest in this renewable energy. Since a system can be truly sustainable by achieving the energetic, ecological and economic sustainability, the present study will focus on the technical characteristics and performance analysis of the wind energy systems. The relations between reliability, availability, energy and exergy efficiency, risk management and the environmental impact of the wind energy systems are investigated in the context of this study. It is concluded that the wind characteristics data and the wind speed are the main effective parameters on its reliability and availability. It is also revealed that considering the system loss, exergy efficiency results of the wind energy systems are more reliable than the energy efficiencies. Due to avoid future failure of the systems, the causes of the failure are investigated and it was concluded that the structural failures caused by storms and strong winds are known as the most prevalent failures.

Effects of Pregabalin on Central Sensitization in Patients with Chronic Pancreatitis in a Randomized, Controlled Trial

BackgroundIntense abdominal pain is the dominant feature of chronic pancreatitis. During the disease changes in central pain processing, e.g. central sensitization manifest as spreading hyperalgesia, can result from ongoing nociceptive input. The aim of the present study is to evaluate the effect of pregabalin on pain processing in chronic pancreatitis as assessed by quantitative sensory testing (QST).MethodsThis randomized, double-blind, placebo-controlled trial evaluated effects of pregabalin on pain processing. QST was used to quantify pain processing by measuring thresholds to painful electrical and pressure stimulation in six body dermatomes. Descending endogenous pain modulation was quantified using the conditioned pain modulation (CPM) paradigm to elicit a DNIC (diffuse noxious inhibitory controls) response. The main effect parameter was the change in the sum of all body pain threshold values after three weeks of study treatment versus baseline values between both treatment groups.Results64 patients were analyzed. No differences in change in sum of pain thresholds were present for pregabalin vs. placebo after three weeks of treatment. For individual dermatomes, change vs. baseline pain thresholds was significantly greater in pregabalin vs. placebo patients for electric pain detection threshold in C5 (P = 0.005), electric pain tolerance threshold in C5 (P = 0.04) and L1 (P = 0.05), and pressure pain tolerance threshold in T4 (P = 0.004). No differences were observed between pregabalin and placebo regarding conditioned pain modulation.ConclusionOur study provides first evidence that pregabalin has moderate inhibitory effects on central sensitization manifest as spreading hyperalgesia in chronic pancreatitis patients. These findings suggest that QST can be of clinical use for monitoring pain treatments in the context of chronic pain.Trial RegistrationClinicalTrials.gov NCT00755573

An optimization analysis on electroless deposition of Al2O3/Cu core-shell nanostructures

In this study, Al2O3/Cu core-shell nanostructure was fabricated by electroless plating of copper on Al2O3 particles. In order to reach to the maximum efficiency of electroless deposition, the influence of main effective parameters such as type of pretreatment process, HCHO/CuSO4·5H2O molar ratio, C4H4O6KNa·4H2O/CuSO4·5H2O molar ratio, pH, pouring rate, concentration of Al2O3 particles, bath temperature, plating time, stirring speed and Al2O3 particle size were investigated. The morphology, uniformity, and chemical composition of the activated and Cu coated Al2O3 particles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results show that, by optimization on the electroless bath composition and the process parameters, using minimum chemicals usage maximum copper plating rate of 19.51% on the surface of Al2O3 particles is obtained. As result of copper deposition on the surface of Al2O3 nanoparticles, uniform shells with about 10nm thicknesses was fabricated on the Al2O3 nanoparticles.

Investigation of the Effect of Electrospun Polyethersulfone Nanofibers in Membrane

One dimensional (1D) nanostructure materials such as nanowires, nanofibers, and nanorods with porous structures have potential for use in various applications. Electrospinning is one of the versatile techniques with the ability of producing cost-effective, large production, highly porous nanofibers and membrane with large surface to volume ratios. Poly ether sulfone (PES) is a kind of special engineering plastic with good processing characteristics. In this paper, synthesis of PES membrane was investigated by two main methods, i.e. phase inversion and electrospiing. For electrospining, the main effective parameters such as concentration of polymer and solvent, for finding the optimized condition of electrospun PES membrane was studied. The produced membranes were characterized by SEM for morphology and BET observation of surface area, permeability, flux, and mechanical propertise for different applications.

IMPACT OF ALCOHOLIC SOLVENTS ON THE RECOVERY OF PHOSPHOLIPIDS IN HPLC ANALYSIS

The lipid quantification of liposomal preparations is primarily performed by HPLC analysis; therefore, reversed phase and normal phase HPLC techniques have been successfully developed. While the optimization of separation performances and the establishment of appropriate detection systems have been studied in detail, the matrix effect of the aqueous environment of liposomes has been less recognized, although this might significantly affect the final results of individual lipids used in liposomal formulations. A series of solubilization studies were performed to prove the effect of increasing water amount in certain lipid standards. Calibration curves of selected lipids were established in pure methanol, isopropanol, and additionally in both solvents containing 10% water for the lipid quantification of liposomal samples. Furthermore, the physical properties of the selected solvents were correlated with the calibration curves to identify their contribution to the magnitude of the peak areas. By employing this experimental design we could demonstrate that the recovery of individual lipids by RP-HPLC is heavily dependent on the solvent itself as well as the final water content of the sample. It could be identified that for DOTAP, the density of the solvent is the main effective parameter. Therefore, to obtain reliable results of liposomal suspensions either the related calibration stock solutions need to be adjusted properly to the solute matrix or alternatively quantification can be performed with the established model.

Logistic response models with item interactions

Items that are clustered according to shared content may violate the principle of conditional independence commonly used in item response theory. This paper investigates the capabilities of a logistic item response model in relation to locally dependent item responses. The model includes main effect and interaction parameters that are computed as linear functions of the latent trait. The paper explains the interpretation of the parameters, the maximum likelihood estimation algorithm, the information matrix and some results concerning parameter identifiability. The problem of over-fitting the data is addressed in a simulation study, and two real data examples are described to illustrate the approach, one from the context of a sample survey and the other from ability testing using testlets.

Experimental study of the electrical properties of copper nitride thin films prepared by dc magnetron sputtering

In this work the main effective parameters on the electrical resistivity of copper nitride thin films are investigated. Copper nitride thin films were successfully deposited on glass substrates by reactive dc magnetron sputtering at room temperature but different sputtering time. Working gas was a mixture of argon and nitrogen with equal amounts. The effect of deposition time on the structural, optical and electrical properties of deposited films was investigated. X-ray diffraction measurements show different lattice orientation in the structure of deposited films. By increasing the time of sputtering an orientation change from (100) to (111) can be observed in the films. Film morphology of samples is not changed with the sputtering time. The optical transmittance of deposited films decreases with increasing the deposition time. Results confirm that when the amount of nitrogen in working gas is 50%, we have more (100) planes in the structure of the deposited films, leads to higher resistivity of the films.

Rotational analysis of 6ν 3 and 6ν 3+ν 2−ν 2 bands of 14N 216O from ICLAS spectra between 12,760 and 12,900 cm −1

The absorption spectrum of nitrous oxide (N 2O) has been recorded by Intracavity Laser Absorption Spectroscopy between 12,760 and 12,900 cm −1. The rotational analysis led to an improved determination of rovibrational parameters of the 6ν 3 and 6ν 3+ν 2–ν 2 bands of 14N 2 16O. The high J rotational levels of the (0 0 06) and (0 1 16) upper states were found perturbed by an anharmonic interaction. Line intensity values of the 6ν 3 band are provided and the main effective dipole moment parameter has been determined.

Comparison of multimarker logistic regression models, with application to a genomewide scan of schizophrenia

BackgroundGenome-wide association studies (GWAS) are a widely used study design for detecting genetic causes of complex diseases. Current studies provide good coverage of common causal SNPs, but not rare ones. A popular method to detect rare causal variants is haplotype testing. A disadvantage of this approach is that many parameters are estimated simultaneously, which can mean a loss of power and slower fitting to large datasets.Haplotype testing effectively tests both the allele frequencies and the linkage disequilibrium (LD) structure of the data. LD has previously been shown to be mostly attributable to LD between adjacent SNPs. We propose a generalised linear model (GLM) which models the effects of each SNP in a region as well as the statistical interactions between adjacent pairs. This is compared to two other commonly used multimarker GLMs: one with a main-effect parameter for each SNP; one with a parameter for each haplotype.ResultsWe show the haplotype model has higher power for rare untyped causal SNPs, the main-effects model has higher power for common untyped causal SNPs, and the proposed model generally has power in between the two others. We show that the relative power of the three methods is dependent on the number of marker haplotypes the causal allele is present on, which depends on the age of the mutation. Except in the case of a common causal variant in high LD with markers, all three multimarker models are superior in power to single-SNP tests.Including the adjacent statistical interactions results in lower inflation in test statistics when a realistic level of population stratification is present in a dataset.Using the multimarker models, we analyse data from the Molecular Genetics of Schizophrenia study. The multimarker models find potential associations that are not found by single-SNP tests. However, multimarker models also require stricter control of data quality since biases can have a larger inflationary effect on multimarker test statistics than on single-SNP test statistics.ConclusionsAnalysing a GWAS with multimarker models can yield candidate regions which may contain rare untyped causal variants. This is useful for increasing prior odds of association in future whole-genome sequence analyses.

Role of mixture richness, spark and valve timing in hydrogen-fuelled engine performance and emission

The use of hydrogen as an engine fuel has a great potential for reducing exhaust emissions. With the exception of a little amount of hydrocarbon emissions originating from the lubricating oil, NOx is the only pollutant emitted. The special properties of hydrogen compel much more study on hydrogen internal combustion engines (ICEs). Studying and analyzing the behavior of hydrogen ICE and its sensitivity to controllable parameters can help designers to have better understanding over hydrogen characteristics and its combustion in an ICE. In this paper, firstly a quasi-dimensional two-zone thermodynamic model of an SI hydrogen ICE is developed and validated by experimental data. The model is used as an engine simulator. Spark advance (SA), air to fuel ratio and valve timing are selected as the main effective and controllable parameters on engine emissions and performance characteristics. Valve timing parameter is defined as the intake and exhaust valves’ lift, opening time and duration. Secondly, the effects of variation of the mentioned three parameters on emission and performance characteristics of the modeled engine are illustrated. Finally, the reasons of the engine behavior and characteristics under variations of these parameters are fully discussed.

플랩핑 에어포일에 대한 비틀림 유연성의 영향

본 연구에서는 플래핑 운동하는 에어포일에 대한 비틀림 유연성의 영향을 조사하였다. 비틀림 유연성이 있는 에어포일의 공기력은 2차원 비정상 와류 패널 방법을 이용하여 계산하였다. 플래핑 에어포일의 공탄성 해석을 위해 2차원의 typical section 모델이 사용되었다. 주요한 파라미터로서 비틀림 유연성과 가진주파수가 고려되었다. 인 무거운 에어포일 조건에서는 주파수비가 0.75 부근에서 추력 최대점이 발견되었다. 이 추력치를 경계로 두 가지 다른 운동이 관찰되었으며, 하나는 관성 지배 운동(inertia driven deformation motion)이고, 다른 하나는 진동 지배 운동(oscillation driven deformation motion)이다. 또한, 최대 추력 상태에서는 비틀림 유연성과 가진주파수에 관계없이 위상각이 85도를 유지하였다. In this paper, the effects of torsional flexibility on a flapping airfoil are investigated. The aerodynamic forces of a torsional flexible flapping airfoil is computed using 2-D unsteady vortex panel method. A typical-section aeroelastic model is used for the aeroelsatic calculation of the flapping airfoil. Torsional flexibility and excitation frequency are considered as main effective parameters. Under heavy airfoil condition , the thrust peak is observed at the points where the frequency ratio is about 0.75. Based on this peak criterion, there exists two different motions. One is an inertia driven deformation motion and the other is an oscillation driven deformation motion. Also, in the thrust peak condition, the phase angle is kept 85 degrees, independent of the torsional flexibility and the excitation frequency.

Enhanced Sodium Retention After Acute Nitric Oxide Blockade in Mildly Sodium Loaded Patients With Essential Hypertension

In essential hypertension (ESS) whole body and vascular nitric oxide (NO) synthesis is generally thought to be reduced. We therefore investigated the systemic and renal responses to acute treatment with N(G)-monomethyl-l-arginine (L-NMMA), a competitive NOS-inhibitor, in 12 patients with ESS and 18 healthy controls (CON) in a randomized, placebo-controlled study. Main effect parameters were renal hemodynamics (glomerular filtration rate [GFR] and renal plasma flow [RPF]), systemic blood pressure (BP), and fractional excretions of sodium (FE(Na)) and lithium (FE(Li)). Experiments were performed on two occasions for each subject studying the effects of either L-NMMA (3 mg/kg intravenously) or placebo. The patients with ESS were studied after at least 14 days off antihypertensive medication. Renal hemodynamics were assessed by the clearances of (125)I-hippuran (RPF) and (51)Cr-EDTA (GFR). The L-NMMA induced a significant increase in systemic BP and significant reductions in RPF, FE(Na), and FE(Li) in both groups. The increase in diastolic BP was significantly attenuated in ESS (ESS: 8% +/- 2% v CON: 14% +/- 2%, P < .05). The GFR and RPF were equally reduced by L-NMMA in both groups (RPF(ESS): -19% +/- 4% v RPF(CON): -15% +/- 3%, P = not significant [NS]). However, the reduction in FE(Na) was enhanced in ESS (ESS: -42% +/- 7% v CON: -25% +/- 3%, P < .01). The FE(Li) decreased equally in both groups (ESS: -17% +/- 2% v CON: -17% +/- 6%, P = NS). It is concluded that acute NO blockade in ESS is accompanied by a reduced systemic pressor response, an unchanged renal hemodynamic response, and an enhanced reduction in FE(Na). The results suggest that patients with essential hypertension are highly dependent on NO to maintain sodium excretion.

Infliximab in the therapy of rheumatoid arthritis

Система комплексной поддержки и сопровождения научного журнала Elpub позволяет запустить двуязычный сайт журнала со встроенной системой электронной редакции в соответствии с лучшими издательскими практиками, а так же предусматривает техническую и методическую поддержку со стороны специалистов НЭИКОН.

A Plackett–Burman design for screening of the operation variables in the formation of salbutamol sulphate particles by supercritical antisolvent

A Plackett–Burman experimental design was applied for screening of the influence of various processing parameters in micronization of salbutamol sulphate using the supercritical antisolvent process. Methanolic solutions of the drug were injected into supercritical carbon dioxide and process parameters, such as pressure, temperature, concentration of drug solution, nozzle internal diameter, drug solution flow rate and injection interval were changed at two levels. Morphology, size characteristics and density of produced particles were evaluated as the response. In all conditions, some needle-like particles with different size and bulk densities were obtained. Analysis of the results showed that the nozzle internal diameter and the flow rate of drug solution were the main effective parameters on the particles size. In the case of bulk density of powders, none of the parameters had pronounced effect; however the flow rate was more effective than others.

The extracorporeal perfusion of the swine uterus as an experimental model: The effect of tocolytic drugs

Objective Comparison of the effect of tocolytic drugs on isolated swine uterus preparations. Study design Forty swine uteri were perfused with the aim to preserve a viable organ, which should be responsive to oxytocic hormones and tocolytic pharmaca. An intrauterine catheter recorded the pressure changes. After initiation of rhythmical uterine contractions we administered known tocolytic drugs (fenoterol, ritodrine, terbutaline, propofol, acetylsalicylic acid, alcohol, atosiban, verapamil, and glyceryl trinitrate) in various concentrations. Results Perfusate pH and lactate, partial oxygen and carbon dioxide tensions, and oxygen saturation in the perfusate showed good preservation of the organ for up to 8 h. All substances showed a tocolytic effect on the swine uterus. The effect varied substantially with regard to the length of the contraction free intervals, which was our main effect parameter. Fenoterol, acetylsalicylic acid, and alcohol showed the most and glyceryl trinitrate the least powerful effect. Conclusions A direct comparison of various tocolytic substances in the same experimental model showed the best effect for fenoterol. Furthermore, we could demonstrate that the swine uterus perfusion system is a suitable model to study the influence of various conditions like the administration of drugs or the induction of oxidative stress on the uterus function.

Effect of potential evapotranspiration estimates on effective parameters and performance of the MIKE SHE-code applied to a medium-size catchment

The effect of the method of calculating a time series of crop potential evapotranspiration (ET p) on both the model performance and the magnitude of the main effective parameters of a distributed hydrological model was assessed on the basis of an independent multi-calibration. The ET p was estimated as a function of the reference evapotranspiration (ET o) by means of a crop coefficient approach. Three methods for deriving ET o estimates were used in modelling a medium size catchment in Belgium: (A) Food and Agriculture Organisation (FAO) FAO-24 standard approach; (B) FAO-24 approach but used with coefficients, for both the wind and the Stefan-Boltzmann equations, differing from the standard formulation; and (C) FAO-56 standard approach. For assessing the performance of the estimation approaches, the point scale ET o outputs of the generation methods were compared to local point scale ET o guidelines derived from previous research. The outputs of generation method B and of the generation method C showed a close agreement with the local point scale ET o guidelines. Their effect (to a catchment scale) on the performance of the hydrological model also seemed to be comparable. The best model performance was obtained by using the higher ET o data generated by method A. The research also revealed a significant dependency of some of the effective parameters on the different ET p estimates; especially of those parameters related to the computation of the actual evapotranspiration (ET act).