The effect of self-reported and observed job conditions on depression and anxiety symptoms: A comparison of theoretical models.

The demand/control/support and effort/reward imbalance models have relied on self-reported methods to describe how poor psychosocial working conditions lead to harmful health outcomes. The hindrance/utilization model uses an observational methodology to assess these relationships. Cross-sectional observational and self-reported data from 98 civil servants participating in the Whitehall II Study of British civil servants were used to test whether work conditions measured by each of the three theoretical models explained a significant amount of the variance in depression and anxiety symptoms. Observational measures were also used to assess potential common methods variance bias between the self-reported job conditions and the outcomes. Results showed that the demand/control/support model explained the most variance in depression and anxiety symptoms and the associations were not wholly due to common methods variance. Moreover, measures associated with job resources (e.g., skill discretion, social support and skill utilization) had a protective effect on depression and anxiety symptoms. Exertion-related conditions (e.g., demands, effort, over commitment) were not consistently associated with depression or anxiety symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterizing nicotine withdrawal in pregnant cigarette smokers.

Maternal smoking is a leading preventable cause of poor pregnancy outcomes and infant morbidity and mortality. Whereas pregnancy has been thought of as a "window of opportunity" when women are more motivated to change health behaviors such as smoking, only 20% of pregnant women quit smoking upon learning they are pregnant and remain abstinent at the end of the pregnancy. Greater understanding of possible obstacles to smoking during pregnancy, such as nicotine withdrawal, is needed. The symptoms of nicotine withdrawal have been well characterized in nonpregnant smokers, but there has been only 1 report conducted during pregnancy, and that was a retrospective study. The aim of the present study was to characterize nicotine withdrawal and craving in pregnant cigarette smokers. These data were collected as part of prospective clinical trials assessing the efficacy of voucher-based incentives to promote abstinence from cigarette smoking during pregnancy and postpartum. The authors examined results from the Minnesota Nicotine Withdrawal Scale (J. R. Hughes & D. K. Hatsukami, 1998) in 27 abstainers (reported no or very low levels of smoking, which was confirmed biochemically) and 21 smokers (smoked at >80% of their baseline smoking level) during the first 5 days of a cessation attempt. Abstainers reported more impatience, anger, and difficulty concentrating than did smokers. The results also suggest that pregnant smokers generally may have elevated baseline levels of withdrawal, which need to be considered in the design and analysis of future studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ultra-high pressure homogenisation of milk: technological aspects of cheese-making and microbial shelf life of a starter-free fresh cheese

Fresh cheeses from pasteurised (80 °C for 15 s), homogenised-pasteurised (15 + 3 MPa at 60 °C; 80 °C for 15 s) or ultra-high pressure homogenised milks (300 MPa and inlet temperature of 30 °C) were produced in order to evaluate different technological aspects during cheese-making and to study their microbial shelf life. Although the coagulation properties of milk were enhanced by ultra-high pressure homogenisation (UHPH), the cheese-making properties were somewhat altered; both conventional homogenisation and UHPH of milk provoked some difficulties at cutting the curd due to crumbling and improper curd matting due to poor cohesion of the grains. Cheese-milk obtained by UHPH showed a higher microbiological quality than milk obtained by conventional treatments. Starter-free fresh cheeses made from UHPH-treated milk showed less syneresis during storage and longer microbiological shelf-life than those from conventionally treated milk samples.     

Fatty acid composition of black bear (Ursus americanus) milk during and after the period of winter dormancy

Black bears give birth and lactate during the 2–3-mon fast of winter dormancy. Thereafter the female emerges from the den with her cubs and begins to feed. We investigated fatty acid patterns of milk from native Pennsylvania black bears during the period of winter dormancy, as well as after den emergence. Throughout winter dormancy, milk fatty acid composition remained relatively constant. The principal fatty acids at all times were 14∶0, 16∶0, 16∶1, 18∶0, 18∶1, 18∶2n−6, 18∶3n−3 and 20∶4n−6. After den emergence, large changes occurred in almost all the fatty acids, particularly in 18∶2n−6 and 18∶3n−3. Large variability among the active free-ranging animals likely reflected differences in diet. In a carnivore, with apparently limitedde novo synthesis of fatty acids, milk fatty acid composition may be affected by factors such as transition from reliance on stored lipids to feeding, and by temporal changes in dietary intake. Based on a paper presented at the Symposium on Milk Lipids held at the AOCS Annual Meeting, Baltimore, MD, April 1990.     

Use of laser scanning confocal microscopy for characterizing changes in film thickness and local surface morphology of UV-exposed polymer coatings

Laser scanning confocal microscopy (LSCM) has been used to characterize the changes in film thickness and local surface morphology of polymer coatings during the UV degradation process. With the noninvasive feature of LSCM, one can obtain thickness information directly and nondestructively at various exposure times without destroying the specimens or deriving the thickness values from IR measurement by assuming uniform film ablation. Two acrylic polymer coatings were chosen for the study, and the physical and chemical changes of the two systems at various exposure times were measured and analyzed. Those measurable physical changes caused by UV exposure include film ablation, formation of pits and other surface defects, and increases in surface roughness. It was found in both coatings that changes in measured film thickness by LSCM were not correlated linearly to the predicted thickness loss using the changes in the CH band obtained by the Fourier Transform Infrared (FTIR) spectroscopy measurements in the later degradation stages. This result suggested it was not a uniform film ablation process during the UV degradation. At later stages, where surface deformation became severe, surface roughness and profile information using LSCM were also proven to be useful for analyzing the surface degradation process Presented at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 13–14, 2004 in Philadelphia, PA.     

Quasi-Diamond Platelet-Shaped Zinc Oxide Nanostructures Display Enhanced Antibacterial Activity

The current study compares the antibacterial activity of zinc oxide nanostructures (neZnO). For this purpose, two bacterial strains, Escherichia coli (ATCC 4157) and Staphylococcus aureus (ATCC 29213) were challenged in room light conditions with the aforementioned materials. Colloidal and hydrothermal methods were used to obtain the quasi-round and quasi-diamond platelet-shape nanostructures. Thus, the oxygen vacancy (V_O) effects on the surface of neZnO are also considered to assess its effects on antibacterial activity. The neZnO characterization was achieved by X-ray diffraction (XRD), a selected area electron diffraction (SAED) and Raman spectroscopy. The microstructural effects were monitored by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Furthermore, optical absorption ultraviolet visible spectrophotometry (UV-Vis) and X-ray photoelectron spectroscopy (XPS) analyses complement the physical characterization of these nanostructures; neZnO caused 50 % inhibition (IC₅₀) at concentrations from 0.064 to 0.072 mg/mL for S. aureus and from 0.083 to 0.104 mg/mL for E. coli, indicating an increase in activity against S. aureus compared to E. coli. Consequently, quasi-diamond platelet-shaped nanostructures (average particle size of 377.6±10 nm) showed enhanced antibacterial activity compared to quasi-round agglomerated particles (average size of 442.8±12 nm), regardless of Vo presence or absence.     

DUAL-TEMPERATURE ION EXCHANGE FRACTIONATION

ABSTRACT

This paper reviews the results obtained by studying the dual-temperature ion-exchange fractionation (DTIXF) technique. The DTIXF is based on the use of different affinity at different temperatures of ion exchangers towards ions to be separated. This technique allows to design absolutely reagentless and, as a result, wasteless fractionation technology. The review considers the temperature dependencies of selectivity of commercially available ion-exchange (LX) resins towards components of ionic mixtures of different complexity starting from binary model systems up to naturally existing nonacomponent effluents. A novel approach for predicting the temperature sensitivity of a given LX system is presented and discussed. The same approach has been shown to be applicable for the design of IX resins with temperature-dependent selectivity. The paper also reports the results obtained in the practical application of DTIXF technique for concentration of magnesium from seawater and copper from acidic mine waters. The flowsheets of DTLXF processes are proposed and discussed.     

Improvement of the deflocculating power of polyacrylates in ceramic slips by small additions of quaternary ammonium salts

In this work, we examine the effect of small additions of cationic quaternary ammonium salts (QAS) of different molecular weight on the rheology of an industrial ceramic suspension deflocculated with sodium polyacrylate and sodium metasilicate. The observed shear thinning behaviors obey the typical power law of fluid rheology. In order to characterize the rheological behavior of these slurries, three new parameters are introduced: a low shear rate consistency index and two transient viscosities, distant from the equilibrium, after increasing and decreasing the shear rates. These parameters vary with polyacrylate molecular weight and on additions of small quantities of QAS, which we found to be useful for decreasing the slurry viscosity.     

Microstructure and morphology of amine-cured epoxy coatings before and after outdoor exposures—An AFM study

Atomic force microscopy (AFM) has been used to study the morphology and microstructure of an amine-cured epoxy before and after outdoor exposure. Measurements were made from samples prepared in an essentially CO₂-free, H₂O-free glove box and from samples prepared in ambient conditions. For those prepared in a CO₂-free glove box, AFM imaging was conducted on (1) an unexposed air/coating surface, (2) an unexposed coating bulk, (3) an unexposed coating/substrate interface, and (4) a field exposed air/coating surface. For samples prepared in ambient conditions, only the unexposed air/coating surface was investigated. The same regions of the exposed samples were scanned periodically by the AFM to monitor changes in the surface morphology of the coating as UV exposure progressed. Small angle neutron scattering and Fourier transform infrared spectroscopy (FTIR) studies were performed to verify the microstructure and to follow chemical changes during outdoor exposure, respectively. The results have shown that amine blushing, which occurs only under ambient conditions, had a significant effect on the surface morphology and microstructure of the epoxy. The surface morphology of the samples prepared under CO₂-free, dry conditions was generally smooth and homogeneous. However, the interface and the bulk samples clearly revealed a two-phase structure consisting of bright nodular domains and dark interstitial regions, indicating an inhomogeneous microstructure. Such heterogeneous structure of the bulk was in good agreement with results obtained by small angle neutron scattering of unexposed samples and by AFM phase imaging of the degraded sample surface. The relationship between submicrometer physical changes and molecular chemical degradation is discussed. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

Toward the prediction of porous membrane permeability from morphological data

One of the challenges in membrane technology is predicting permeability in porous membranes for liquid applications in an easy and inexpensive way. This is the aim of this work. To achieve this objective, several techniques can be considered. In this study, a morphological approach from two‐dimensional scanning electron micrographs is proposed. First, numerical membrane morphological parameters have been determined from micrographs by using the QUANTS tool, which applies a texture recognition process. Second, the obtained data have been fit to the Darcy's and Hagen–Poiseuille models to calculate permeations. The QUANTS results have also been compared with the ones obtained through a mercury porosimeter, which is a classic and well‐known methodology. Each parameter of the Hagen–Poiseuille model has been analyzed. A comparison between experimentally measured permeations and calculated ones has been performed. An even easier approach is proposed to predict flow rate with the only knowledge of membrane surface mean pore size. This method is based on cross‐section pore size interpolation by using function fits from surface mean pore sizes. The obtained results show a reasonable agreement between measured and computed results, making this technique a valid approach for predicting membrane permeability. POLYM. ENG. SCI., 56:118–124, 2016. © 2015 Society of Plastics Engineers