An efficient numerical scheme for solving Hammerstein integral equation arisen in chemical phenomenon

AbstractIn Science and engineering, so many nonlinear phenomena are presented as partial differential, ordinary differential and integral equation models. So in this article, our aim is to study on Hammerstein type nonlinear integral equation μS(σ)=−RTLn[∫abPS(σ∘)exp{−ϵ(σ,σ∘)+μS(σ∘)RT}dσ∘] Where R is the gas constant, T the temperature, the term ϵ(σ,σ∘) denotes the interaction energy expression for the segments with screening charge density σ and σ∘ respectively, the molecular interaction in solvent is PS(σ) and the chemical potential of the surface segments is described by μS(σ) that should be determined. This integral equation forms the basis for the conductor-like screening model for real solvents (COSMO-RS) which is appeared in chemical phenomena. Some of numerical methods usually use techniques based on a projection in terms of some basis functions or use some quadrature formulas, and the convergence rate of these methods are usually of polynomial order with respect to N, where N represents the number of terms of the expansion or the number of points of the quadrature formula. Also, in projection methods nonlinear Hammerstein integral equation is reduced to the nonlinear algebraic equations which solving them in large scales needs high memory capacity and CPU time and because of error propagation convergence of numerical technique may be at risk. So this paper presents a powerful numerical approach based on Sinc quadrature which has exponential type convergence rate to solve conductor-like screening model for real solvents (COSMO- RS). The approach is based on preparing an iterative method to recognize the Hammerstein integral equation for the determination of the chemical potential of a surface segment as a function of screening charge density

Letter to the Editor on: Prostate-specific antigen density is predictive of outcome in suboptimal prostate seed brachytherapy

In this study, a novel method was developed to measure acidic and basic drugs in biological and wastewater samples. The method used magnetic nanoparticles based on Vortex-Assisted Dispersive Micro-Solid Phase Extraction (SPE) and then identifying with HPLC-UV. The magnetic nanoparticle (Fe3O4@SiO2@Kit-6@NH2) has been used as an efficient adsorbent for the extraction of acidic and basic drugs ibuprofen (IFB), fenoprofen calcium (FPC), methocarbamol (MTC), and clonazepam (CZP). The magnetic nanoparticle was characterized by techniques including SEM, XRD, EDX, and FT-IR. The effect of various parameters in the V-D-μ-SPE method was studied completely through the design of the response surface methodology (RSM) of the Box–Behnken design (BBD) based response method and the utility function. The parameters affecting the extraction efficiency were optimized including sample pH, adsorbent amount, absorption time, the salt concentration in the sample solution, CTAB of concentration, desorption time, and the volume of an eluent. After optimization, the limit of detection and calibration curve in the linear range were obtained 0.062–0.32 μg L−1 and 0.1–800 μg L−1, respectively. Its linear correlation was R2> 0.9951. The relative standard deviation (n = 5) was between 2.4 and 5.1. Finally, this method was used to determine target analytes in human serum, urine, and wastewater. • In this study, for the first time, a novel method for the determination of some drugs from human serum, urine, and wastewater samples. • The Synthesized Fe3O4@SiO2@Kit-6@NH2 NPs based V-D-μ-SPE was characterized by techniques including SEM, XRD, EDX, and FT-IR. • The effects of various parameters in the V-D-μ-SPE methods were studied through the design of the RSM of BBD. © 202

Hormonal sex reversal of rainbow trout (Oncorhynchus mykiss) by ethynylestradiol-17α (EE2)

Rainbow trout (Oncorhynchus mykiss) females grow larger and mature later than males, making all-female stocks economically advantageous. The objective of this research was to develop methods for the production of monosex populations of trout through the use of sex steroids. The synthetic estrogen ethynylestradiol-17α (EE2) was administered in single period-immersion treatment of 400 µg/l for 1, 2, 4 and 8 h to groups of newly-hatched sac fries of rainbow trout and in a 30 day dietary treatment of 5, 10, 15 and 20 mg/kgf of newly swum up fries. 73.4 And 94.5% females were obtained with 1 and 2-h single-immersion of EE2 respectively (38% female in control). However, higher doses progressively reduced the survival drastically. Sex ratios of dietary treatment of fry were 60, 57.4, 78 and 94% females respectively. Treatments also resulted in a slight increase of both weight and length. This increase was related to the method of hormonal exposure (dietary > immersion), but not dosage-dependent for utilized hormone. This demonstrates that the direct feminization of rainbow trout can be achieved and resulted in sex reversal ratio effectively but not decreased the growth, as observed in hormonal sex reversed females, and it would be a noticeable approach to the direct feminization of trout

In vitro propagation of four Iranian grape varieties: Influence of genotype and pretreatment with arbuscular mycorrhiza

There is a great demand for table grape saplings, mainly for commercial varieties indicating that micropropagation could be an effective method for their mass propagation. Internal contamination in woody plant species is an important problematic issue and arbuscular mycorrhizal fungi (AMF) have been known as potential plant biological protectors. In the present study, the glasshouse grown mother plants of four grape varieties ('Asgari', 'Khalili', 'Keshmeshi', and 'Shahroudi') were inoculated with AMF as pre-treatment. The fungi strains were Glomus mosseae, G. fasciculatum, G. intraradices and a mixture of all three species. The comparative in vitro performance of these genotypes was evaluated following optimization of in vitro growth conditions for each genotype. Furthermore, the positive effect of AMF inoculation of stock plant on micropropagation process was studied. Changes in biochemical features (total chlorophylls, total phenols and total sugars), growth parameters (root length and total leaf area) and in vitro behavior of AMF pretreated as well as control explants were recorded. The mycorrhizal association with grapevine roots was confirmed following root staining and evaluation of colonization rate. The results revealed a distinct difference and clear genotypic effect on various in vitro parameters of studied grape genotypes. The utilized inocula were found to have the capability of mycorrhizal association with grapevine roots, leading to enhancing phenolics as a defense mechanism, increasing sugars and chlorophyll and finally growth of whole plant corresponding to the grape variety and AMF strain. These results confirmed that health and physiological conditions of the stock plants are important parameters for in vitro grape culture establishment and suggest the integration of mycorrhizal technology with tissue culture to accomplish better results

Quantitative phase evolution during mechano-synthesis of Ti-Ni-Cu shape memory alloys

Cataloged from PDF version of article.Ti-41Ni-9Cu shape memory alloy was synthesized by mechanical alloying of pure elemental Ti, Ni, and Cu powders using high-energy ball milling. The qualitative and quantitative phase analyses of the as-milled powders were done by X-ray diffraction (XRD) using Rietveld refinement and the alloys microstructure was studied by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Concerning the results, by milling evolution, the dissolution of the primary materials occurred at different rates and a considerable amount of the amorphous phase as well as B19′-martensite and B2-austenite was created. The formation of Ni solid solution was also evidenced prior to its dissolution. It was found that at sufficient milling time, the mechano-crystallization of the amorphous phase occurred and at the end of milling, the B19′-martensite is the dominant phase of the structure. © 2012 Elsevier B.V. All rights reserve

Effect of milling Time on the Structure, Micro-hardness, and Thermal Behavior of Amorphous/Nanocrystalline TiNiCu Shape Memory Alloys Developed by Mechanical Alloying

Cataloged from PDF version of article.In the present paper, the effect of milling process on the chemical composition, structure, microhardness, and thermal behavior of Ti-41Ni-9Cu compounds developed by mechanical alloying was evaluated. The structural characteristic of the alloyed powders was evaluated by X-ray diffraction (XRD). The chemical composition homogeneity and the powder morphology and size were studied by scanning electron microscopy coupled with electron dispersive X-ray spectroscopy. Moreover, the Vickers micro-indentation hardness of the powders milled for different milling times was determined. Finally, the thermal behavior of the as-milled powders was studied by differential scanning calorimetery. According to the results, at the initial stages of milling (typically 0-12 h), the structure consisted of a Ni solid solution and amorphous phase, and by the milling evolution, nanocrystalline martensite (B19') and austenite (B2) phases were initially formed from the initial materials and then from the amorphous phase. It was found that by the milling development, the composition uniformity is increased, the inter-layer thickness is reduced, and the powders microhardness is initially increased, then reduced, and afterward re-increased. It was also realized that the thermal behavior of the alloyed powders and the structure of heat treated samples is considerably affected by the milling time. (C) 2013 Elsevier Ltd. All rights reserved

Content Moderation As a Political Issue: The Twitter Discourse Around Trump's Ban

Content moderation — the regulation of the material that users create and disseminate online — is an important activity for all social media platforms. While routine, this practice raises significant questions linked to democratic accountability and civil liberties. Following the decision of many platforms to ban Donald J. Trump in the aftermath of the attack on the U.S. Capitol in January 2021, content moderation has increasingly become a politically contested issue. This paper studies that process with a focus on the public discourse on Twitter. The analysis includes over 9 million tweets and retweets posted by over 3 million unique users between January 2020 and April 2021. First, the salience of content moderation was driven by left-leaning users, and "Section 230" was the most important topic across the ideological spectrum. Second, stance towards Section 230 was relatively volatile and increasingly polarized. These findings highlight relevant elements of the ongoing process of political contestation surrounding this issue, and provide a descriptive foundation to understand the politics of content moderation

Identification and comparison of the yield and composition of essential oil constituents of four Eucalyptus species adapted to the climatic conditions of Khorramabad

Introduction: Eucalyptus has more than 400 species, while only a few species of this genus have been imported in Iran. In this study we aimed to investigate chemical compounds of the essential oils of Eucalyptus species adapted in Lorestan climate. Methods: In this study, the fresh young leaves of four different Eucalyptus species including E. suggrandis, E. globulus subsp. bicostata, E. nitens and E. globulus subsp. maidenii were collected in spring (the middle of May) in khorramabad, Iran. The powder of air-dried leaves of different species of Eucalyptus was subjected to hydro-distillation using a Clevenger-type apparatus. The chemical compositions of different essential oils were detected using gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC/MS) and determination of their retention time (RT), retention index (RI) and Mass Spectra. The obtained data were analyzed using SPSS software. Results: The results of this study indicated that there was significant difference (P&lt;0.01) among the yield and chemical compounds of the essential oils of studied species. The results showed that the yield of essential oil extracted from E. suggrandis, E. globulus bicostata, E. nitens and E. globulus maidenii were 1.12, 1.34, 2.57 and 5.38, respectively. Conclusion: The essential oil constituents of four Eucalyptus species plant were different in among of some compounds. E. globulus maidenii&nbsp; &nbsp;had most content of essential oil and 1.8-Cineole compound so it is necessary to identify quality and quantity characteristics of compounds available in this plant.</p

Identification of environmental risk factors associated with the development of Inflammatory Bowel Disease

BACKGROUND AND AIMS: Multiple genetic and environmental factors are involved in the etiology of inflammatory bowel disease (IBD), consisting of Crohn's disease (CD) and ulcerative colitis (UC) but data on these exposome factors are difficult to identify . Several exposome factors as smoking have been shown to be involved, as for other environmental factors, i.e. stress, results have been conflicting. METHODS: We performed a case-control study including 674 IBD patients of the 1000IBD cohort frequency-matched based on sex and age to 1,348 controls from population based Lifelines Cohort Study. Exposome data was obtained using the validated Groningen IBD Environmental Questionnaire (GIEQ), capturing exposome factors through different stages of life using 844 items, of which 454 applicable to study the role of 93 exposome factors in disease etiology. Logistic regression modeling with Bonferroni correction for multiple testing was applied to estimate the multivariable-adjusted effect of each exposome factor. RESULTS: For IBD, we identified four novel factors; stressful life-events (CD OR2.61/UC OR 2.92), high perceived stress (2.29/2.67), alcohol use (0.40/0.43), and bronchial hyperreactivity (3.04/2.36). Four novel factors were associated with only CD; prenatal smoke exposure (1.89), having a bedpartner (0.53), allergies (2.66) and cowmilk-hypersensitivity (5.87), two solely with UC; carpet flooring (0.57) and neuroticism (1.32). Nine factors were replicated. CONCLUSION: In this study we identified ten novel and replicated nine previous reported exposome factors associated with IBD. Identifying these factors is important for both understanding disease etiology and future prevention strategies to decrease the development of IBD in genetically susceptible persons