•Mixed particles performs better than corresponding individual particles in paint.•The most attractive mineral for NaPAA is TiO2 followed by calcite and calcined kaolin•TiO2 and C.Kaolin exhibit the ...maximum yield stress at their iep, calcite shows a minimum at the iep
Different types of minerals in varying amounts are used in paint formulations depending on the paint characteristic. While titanium dioxide (TiO2) is used as a main pigment to improve the paint properties, some minerals such as calcite and calcined kaolin are used as a filler to decrease the cost of the paint, and in some cases as a substitute for TiO2. An important criterion for developing paint formula, especially for architectural ones, is to load maximum amounts of mineral pigments or fillers as much as possible to satisfy the rheology of the paint. Appropriate type and amount of dispersants is crucial at this stage to get the proper flowability at high amount of pigment and fillers.
Polyacrylic acid sodium salt (NaPAA), a well-known dispersant, is generally used as a commercial dispersant in various paint formulations. Interaction of NaPAA with a group of minerals as single or mixture will be rather different. In the case of paint, as a variety of minerals and reagents are available in a mixture, in order to improve the paint formulation, this complex system should be revealed step by step. In the present study, the interaction of single minerals, titanium dioxide (TiO2), calcined kaolin (C.Kaolin), ground calcite (GCC) and their mixtures as TiO2 + GCC, TiO2 + C.Kaolin and TiO2 + GCC + C.Kaolin in the presence of NaPAA was investigated in terms of adsorption, rheology, and electrokinetic phenomena. The results showed that adsorption plateau, zeta potential and viscosity values of the mixtures were very close to the arithmetic mean of the individual minerals of the mixtures. The most attractive mineral ingredient for NaPAA was TiO2, followed by GCC and C.Kaolin. The mixture of minerals behaved differently at the same dosage of NaPAA compared to the single minerals. It is thus important to adjust the minerals mixtures and dispersant type and dosage to closely tune the paint properties. This study clearly revealed that it is more viable to adjust the desired paint properties using a mixture of minerals of different surface properties than a single mineral.
In recent years, biocementation has emerged as a promising technology for soil improvement research. This eco-friendly and sustainable approach involves a range of biochemical treatments, and its ...effectiveness is influenced by various factors. In this study, the effects of soil grain sizes, treatment duration (3, 6, and 11 days) and cementation solution flow rate (0.266, 0.400, and 0.666 ml/sec) on the engineering properties of treated soil were investigated by using the biocementation technique. The strength, calcite percentages, permeability, morphological appearance and structures of the treated sand soils were examined. According to the results, for each soil, different results were obtained with the same flow rates and treatment times. The highest strength value determined as 2406 kPa in the 11 day treatment at 0.400 ml/sec flow rate for smaller particle size of soil whereas the highest strength value obtained as 1504 kPa in the 11 day treatment at 0.266 ml/sec flow rate for larger particle size of soil. Higher strength results were obtained at lower flow rates (0.266 ml/sec) in samples with large grain diameter while strength results could not be obtained from it after treatment at higher flow rates (0.400, 0.666 ml/sec). In addition, strength results were obtained with a smaller grain diameter at a high flow rate (0.666 ml/sec), but decreased from 1599 to 1190 kPa when raising the treatment duration from 3 to 11 days. The flow rate and treatment duration in studies should therefore be chosen according to the particle size distribution of the soil.
•The program could be carried out in a home environment.•The program increased the interactional behaviors of parents and children.•The program decreased the number of difficult routines.•The program ...was considered as “educational, instructive and a band-aid” by parents.•Issues such as developing systematic psycho-social support systems that increase the full participation and motivation of parents in distance education programs during periods such as pandemics, overcoming difficulties in online data collection, using coaching and counseling systems for the maintenance of information, individualizing the program, making it more interactive and preparing applied training programs on different subjects need to be resolved.
During the COVID-19 pandemic, the development of emergency remote training programs for young children with Down syndrome, learning difficulties, and severe health problems and their parents became a requirement. The present study aimed to evaluate the impact of the “applied emergency remote training program”, prepared to address the needs of parents with children with Down syndrome and to offer them at-home support. It is an evaluative case study conducted with 11 parents of 11-35 months old children with Down syndrome. The findings demonstrated that the program could be conducted in a home environment, it improved the interactional behavior of both parents and children, reduced the number of difficult routines, and was considered as an educational, instructive, and band-aid solution. Issues such as the development of systematic psycho-social support systems that increase full participation and motivation of parents in distance education programs are important during extreme times such as the pandemic. Difficulties in online data collection, the employment of coaching and counseling systems in information maintenance, individualization of the program, the improvement of the interactivity in the program, and the development of applied training programs on different topics still wait for a solution.
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► A new, rapid and sensitive on-line HPLC assay for biothiols was proposed. ► Postcolumn derivatization was performed with methyl-β-cyclodextrin-containing DTNB. ► Biothiols were ...selectively determined individually among other antioxidants. ► The oligosaccharide helped to improve the sensitivity.
A novel on-line HPLC-DTNB method was developed for the selective determination of biologically important thiols (biothiols) such as l-cysteine (Cys), glutathione (GSH), homocysteine (HCys), N-acetylcysteine (NAC), and 1,4-dithioerythritol (DTE) in pharmaceuticals and tissue homogenates. The biothiols were separated on C18 column using gradient elution, reacted with the postcolumn reagent, DTNB in 0.5% M-β-CD (w/v) solution at pH 8, to form yellow-colored 5-thio-2-nitrobenzoic acid (TNB), and monitored with a PDA detector (λ=410nm). With the optimized conditions for chromatography and the post-column derivatization, 40nM of NAC, 40nM of Cys, and 50nM of GSH can be determined. The relative standard deviations of the recommended method were in the range of 3.2–5.4% for 50μM biothiols. The negative peaks of biothiol constituents were monitored by measuring the increase in absorbance due to TNB chromophore. The detection limits of biothiols at 410nm (in the range of 0.04–0.58μM) after post-column derivatization with DTNB+M-β-CD were much lower than those at 205nm UV-detection without derivatization, and were distinctly lower than those with post-column DTNB alone. The method is rapid, inexpensive, versatile, nonlaborious, uses stable reagents, and enables the on-line qualitative and quantitative estimation of biothiol constituents of biological fluids and pharmaceuticals.
An isolate of
Streptomyces decoyicus
M* (code of the isolate) was identified by the sequencing of 16S rRNA gene. It was grown on solid media and secondary metabolites were extracted with
n
-butanol. ...The extract was dried and run in a sodium dodecyl sulphate–polyacrylamide gel (SDS–PAGE, 10%). Two main bands obtained were sliced and the metabolites were regained in
n
-butanol. These two samples were then identified by gas-chromatography–mass spectrometry (GC–MS), and Fourier-transform infrared spectroscopy (FT-IR). The results demonstrated that tromethamine- and 1-dodecanol were the main constituents (band 1: 61% and 17.7%; band 2: 41% and 54%, respectively). This finding maintained that the isolate of
Streptomyces decoyicus
produced high amounts tromethamine- and 1-dodecanol under the conditions investigated.
Health care reform, which started to be restructured after the Alma Ata Declaration, positively contributed to the development of primary health care administrations around the world. In Turkey, the ...Ministry of Health launched a "Health Transformation Program" by initiating the "Family Medicine Model" that influenced the working conditions and job satisfaction of primary health care workers (PHCWs). In this cross-sectional study, we evaluated job satisfaction levels of PHCWs and the factors affecting these levels a decade after the introduction of the health care reform in a province of Turkey.
A total of 223 PHCWs participated in the study and completed a structured questionnaire that probed their views regarding their jobs and working conditions. Additionally, the short version of the Minnesota Satisfaction Questionnaire (MSQ) was administered to each participant. Participants were also asked to indicate whether they had any intention to quit their job, whether they liked their profession and workplace, and whether they were satisfied with their job. Bivariate analysis and binary logistic regression analysis were performed to determine predictors of job satisfaction.
PHCWs were found to be generally dissatisfied with their working conditions and they declared that they were not sufficiently qualified to work in primary care. Their overall satisfaction was found to be moderate (3.21±0.67 out of 5) and the most important predictor for job satisfaction was found to be "Liking the workplace" (OR=3.07; 95% CI=1.46-6.45).
The results indicated that environmental factors for job-related issues need to be examined more intensively for future planning and policy making in primary care.
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The aim of the present work was to investigate the hydrophobicity and polymer compatibility of aminopropylisooctyl polyhedral oligomeric silsequioxane (POSS) - modified ...Na-montmorillonite (Na-MMT) towards developing polymer-clay nanocomposites. The effect of different concentrations of POSS on properties of Na-MMT was studied. The intercalation ability of the POSS molecules into the Na-MMT interlayer was analyzed by X-ray diffraction. It was found that the d001 value was increased with increasing the POSS concentration, indicating the successful intercalation of the POSS molecules into the Na-MMT interlayer. The d001 value was 4.12nm at 0.4 cation exchange capacity (CEC) loading of POSS, increased at a slight rate upon further increase of CEC loading, and finally reached 4.25nm at 1.0 CEC loading of POSS. The results of the thermogravimetric (TGA) analysis confirmed the high thermal stability of the POSS-MMT. The thermal stability was defined as a 5% mass loss (T5) at 0.2 CEC loading of POSS was observed at 352°C and slightly decreased with further increase in the POSS concentration. The porous properties, such as specific surface area (SSA), pore volume, and pore size were estimated by the adsorption of N2 molecules on the Na-MMT surface. The SSA and pore volume were reduced with increasing the concentration of the POSS molecules due to the adsorption of the POSS molecules on the Na-MMT, while the pore size was increased upon the formation of macroporous structure. The interfacial interaction energy between water and POSS-MMT (ΔGClay/Water/ClayIF) was used to evaluate the surface hydrophobicity, and a similar approach was also applied to assess the polymer compatibility of the developed composite. The obtained results confirm that the polymer compatibility of POSS-MMT prepared in this study is better than that of commonly used HDTMA-MMT.
Na-montmorillonite (Na-Mt) from Reşadiye Region of Turkey was modified by three different cationic and two different nonionic surfactants. The raw Na-Mt was purified before modification in order to ...remove mineral impurities other than Mt. The intercalation ability of surfactants into Na-Mt interlayer was investigated by X-ray diffractometry (XRD). Interaction of surfactant with Na-Mt surface was examined by various techniques involving Fourier Transform Infrared Spectroscopy (FTIR), thermal stability by Thermal Gravimetric Analysis (TGA), and the clay-polymer compatibility using surface energy and solubility parameters approaches. The present study was mainly focused on the evaluation of clay-polymer compatibility due to the lack of knowledge in this research field. It was found that different type of surfactants required different methodologies to evaluate the clay-polymer compatibility. It is proposed that the surface energy approach is very suitable for cationic surfactants used in this study due to their hydrophobic nature, however, such approach is not suitable for relatively less hydrophobic nonionic surfactants. The possibility of using the surface energy approach for cationic surfactants and that of solubility parameter for nonionic surfactants is discussed in the light of experimental data and theoretical considerations.
•Reşadiye Na-Mt was purified and modified with cationic and nonionic surfactants.•Intercalation ability, surface and thermal properties of modified Na-Mts were investigated.•The clay-polymer compatibility was evaluated for all surfactants.•Surface energy approach was suitable for cationic surfactants modified Na-Mt.•Solubility parameter approach was selected for nonionic surfactants modified Na-Mt.
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