Effect of pyrophyllite additions on sintering characteristics of fly ash based ceramic wall tiles

Abstract

The sintering characteristics of fly ash-pyrophyllite mixes containing 0-100 wt-% sericitic pyrophyllite have been studied, using 10 wt-% sodium hexametaphosphate as a binding agent and a firing temperature of 950°C. Increasing pyrophyllite content has been observed to increase the impact strength and apparent density and decrease the water absorption of sintered tile samples. Moreover, the presence of pyrophyllite imparted improved thermal shock resistance to the wall tile samples.     

Slow release polymer–iodine tablets for disinfection of untreated surface water

Simple water treatment devices are designed to treat small amounts of drinking water for home use. This study was undertaken to develop an iodine‐releasing polymeric formulation and examine its potential as a domestic water purifier for untreated surface water. The antimicrobial tablet formulation was made from gum arabic (GA), poly(vinylalcohol) (PVA), ethyl cellulose (EC), and poly(vinylpyrrolidone)‐iodine (PVP‐I). The formulation consisted of a dispersible core tablet surrounded by a hydrophilic coating of EC and poly(ethylene glycol) mixture. These stable, non‐vaporizing, and water‐insoluble tablets slowly release iodine through diffusion over 48 h when suspended in water. The swelling behavior and release were observed to be the functions of excipient composition, iodine loading, and coating materials. Iodine release was determined by UV–VIS spectroscopy and volumetric titrations. The tablets were also assessed for antimicrobial activity against Escherichia coli, Staphylococcus aureus, Listeria monocytogenes Scott A, and Salmonella typhimurium. The disinfection efficiency of the developed tablets was compared with a commercial formulation (Potable Aqua®) as both contain iodine‐releasing active compounds and work on the antimicrobial property of released iodine. The difference between the two formulations is that water‐dispersible Potable Aqua® has a higher amount of free iodine quickly available in water thereby making it a fast‐action emergency water purifier, whereas the developed water‐insoluble polymer–iodine tablets act slowly and require 24 h to show the same disinfection efficacy with lower content of iodine in water. Overnight release of iodine in water from polymer–iodine tablets was effective in 99.9% reduction of an initial cell count of ～ 10⁷ colony forming units (cfu)/mL. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The relationship of early alliance ruptures and their resolution to process and outcome in three time-limited psychotherapies for personality disorders.

This study examined the relationship of early alliance ruptures and their resolution to process and outcome in a sample of 128 patients randomly assigned to 1 of 3 time-limited psychotherapies for personality disorders: cognitive–behavioral therapy, brief relational therapy, or short-term dynamic psychotherapy. Rupture intensity and resolution were assessed by patient- and therapist-report after each of the first 6 sessions. Results indicated that lower rupture intensity and higher rupture resolution were associated with better ratings of the alliance and session quality. Lower rupture intensity also predicted good outcome on measures of interpersonal functioning, while higher rupture resolution predicted better retention. Patients reported fewer ruptures than did therapists. In addition, fewer ruptures were reported in cognitive–behavioral therapy than in the other treatments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive behavioral therapy for 4- to 7-year-old children with anxiety disorders: A randomized clinical trial.

Objective: To examine the efficacy of a developmentally appropriate parent–child cognitive behavioral therapy (CBT) protocol for anxiety disorders in children ages 4–7 years. Method: Design: Randomized wait-list controlled trial. Conduct: Sixty-four children (53% female, mean age 5.4 years, 80% European American) with anxiety disorders were randomized to a parent–child CBT intervention (n = 34) or a 6-month wait-list condition (n = 30). Children were assessed by interviewers blind to treatment assignment, using structured diagnostic interviews with parents, laboratory assessments of behavioral inhibition, and parent questionnaires. Analysis: Chi-square analyses of outcome rates and linear and ordinal regression of repeated measures, examining time by intervention interactions. Results: The response rate (much or very much improved on the Clinical Global Impression Scale for Anxiety) among 57 completers was 69% versus 32% (CBT vs. controls), p     

Efficient one-pot preparation of bisalkyl xanthogen disulfides from alcohols

An efficient one-pot synthetic procedure for the preparation of bisalkyl xanthogen disulfides is achieved via oxidation of the in situ generated xanthate salt in an aqueous condition using half an equivalent of molecular iodine in one pot.     

Bunsen section thermodynamic model for hydrogen production by the sulfur–iodine cycle

A model for the Bunsen section of the Sulfur–Iodine thermo-chemical cycle is proposed, where sulfur dioxide reacts with excess water and iodine to produce two demixing liquid aqueous phases (H₂SO₄ rich and HI rich) in equilibrium. Considering the mild temperature and pressure conditions, the UNIQUAC activity coefficient model combined with Engels' solvation model is used. The complete model is discussed, with HI solvation by water and by iodine as well as H₂SO₄ solvation by water, leading to a very high complexity with almost hundred parameters to be estimated from experimental data. Taking into account the water excess, a successful reduced model with only 15 parameters is proposed after defining new apparent species. Acids total dissociation and total H⁺ solvation by water are the main assumptions. Results show a good agreement with published experimental data between 25 °C and 120 °C.     

Interpolymer radical coupling: A toolbox complementary to controlled radical polymerization

The current review focuses on the relevance and practical benefit of interpolymer radical coupling methods. The latter are developing rapidly and constitute a perfectly complementary macromolecular engineering toolbox to the controlled radical polymerization techniques (CRP). Indeed, all structures formed by CRP are likely to be prone to radical coupling reactions, which multiply the available synthetic possibilities. Basically, the coupling systems can be divided in two main categories. The first one, including the atom transfer radical coupling (ATRC), silane radical atom abstraction (SRAA) and cobalt-mediated radical coupling (CMRC), relies on the recombination of macroradicals produced from a dormant species. The second one, including atom transfer nitroxide radical coupling (ATNRC), single electron transfer nitroxide radical coupling (SETNRC), enhanced spin capturing polymerization (ESCP) and nitrone/nitroso mediated radical coupling (NMRC), makes use of a radical scavenger in order to promote the conjugation of the polymer chains. More than a compilation of macromolecular engineering achievements, the present review additionally aims to emphasize the particularities, synthetic potential and present limitations of each system.     

Determination of iodide,iodate and organo-iodine in waters with a new total organic iodine measurement approach

The dissolved iodine species that dominate aquatic systems are iodide, iodate and organo-iodine. These species may undergo transformation to one another and thus affect the formation of iodinated disinfection byproducts during disinfection of drinking waters or wastewater effluents. In this study, a fast, sensitive and accurate method for determining these iodine species in waters was developed by derivatizing iodide and iodate to organic iodine and measuring organic iodine with a total organic iodine (TOI) measurement approach. Within this method, organo-iodine was determined directly by TOI measurement; iodide was oxidized by monochloramine to hypoiodous acid and then hypoiodous acid reacted with phenol to form organic iodine, which was determined by TOI measurement; iodate was reduced by ascorbic acid to iodide and then determined as iodide. The quantitation limit of organo-iodine or sum of organo-iodine and iodide or sum of organo-iodine, iodide and iodate was 5 μg/L as I for a 40 mL water sample (or 2.5 μg/L as I for an 80 mL water sample, or 1.25 μg/L as I for a 160 mL water sample). This method was successfully applied to the determination of iodide, iodate and organo-iodine in a variety of water samples, including tap water, seawater, urine and wastewater. The recoveries of iodide, iodate and organo-iodine were 91–109%, 90–108% and 91–108%, respectively. The concentrations and distributions of iodine species in different water samples were obtained and compared.     

TrkB Receptor Signalling: Implications in Neurodegenerative,Psychiatric and Proliferative Disorders

The Trk family of receptors play a wide variety of roles in physiological and disease processes in both neuronal and non-neuronal tissues. Amongst these the TrkB receptor in particular has attracted major attention due to its critical role in signalling for brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT3) and neurotrophin-4 (NT4). TrkB signalling is indispensable for the survival, development and synaptic plasticity of several subtypes of neurons in the nervous system. Substantial evidence has emerged over the last decade about the involvement of aberrant TrkB signalling and its compromise in various neuropsychiatric and degenerative conditions. Unusual changes in TrkB signalling pathway have also been observed and implicated in a range of cancers. Variations in TrkB pathway have been observed in obesity and hyperphagia related disorders as well. Both BDNF and TrkB have been shown to play critical roles in the survival of retinal ganglion cells in the retina. The ability to specifically modulate TrkB signalling can be critical in various pathological scenarios associated with this pathway. In this review, we discuss the mechanisms underlying TrkB signalling, disease implications and explore plausible ameliorative or preventive approaches.