Expansibility of vermiculites irradiated with microwaves

The effect of microwave power on the expansion of vermiculites was studied at 800 W for different microwave exposure times (from 10 s to 600 s) and compared with the changes after heating to 1000 °C and dehydration in vacuum. The interlayer water molecules of the individual flakes were driven off quickly by microwave irradiation separating the layers. The changes were characterized by X-ray powder diffraction and scanning electron microscopy. Microwave irradiation reduced the time and energy required for the preparation of expanded vermiculite particles. Microwave-heated vermiculites may be useful for some applications, such as intumescent fire barriers. They could also be interesting materials for adsorption of contaminants, such as oil and aromatics compounds (benzene, toluene, chlorobenzene, nitrobenzene, etc.) or heavy metals ions from aqueous solutions, without the need of hydrophobic modification.     

Miscibility behavior of epoxy thermosets loaded with an oligophosphonate

In this study, a commercial epoxy resin was mixed with a phosphorus‐containing oligomer and thermally cross‐linked using a mixture of two aliphatic amines as curing agents. The miscibility and the influence of the phosphorus‐containing oligomer on the characteristics of epoxy thermosets were investigated by scanning electron microscopy (SEM), thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. SEM revealed that phosphorus‐containing oligomer was well dispersed into the epoxy matrix. Dynamic mechanical analysis indicated an increase in storage modulus as the phosphorus‐containing oligomer content loaded into epoxy matrix increased. Thermogravimetric analysis showed that the onset temperature of phosphorus‐containing epoxy thermosets and the peak corresponding to the temperature of decomposition decreased compared with the ones corresponding to the neat epoxy system, whereas the char yield increased with the increase in phosphorus content added into the epoxy networks. To better understand the mechanism of action of phosphorus‐containing epoxy thermosets, the char residue was investigated by SEM and energy‐dispersive X‐ray spectroscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41822.     

Discovery and Characterization of Multiple Classes of Human CatSper Blockers

The cation channel of sperm (CatSper) is a validated target for nonhormonal male contraception, but it lacks selective blockers, hindering studies to establish its role in both motility and capacitation. Via an innovative calcium uptake assay utilizing human sperm we discovered novel inhibitors of CatSper function from a high-throughput screening campaign of 72,000 compounds. Preliminary SAR was established for seven hit series. HTS hits or their more potent analogs blocked potassium-induced depolarization and noncompetitively inhibited progesterone-induced CatSper activation. CatSper channel blockade was confirmed by patch clamp electrophysiology and these compounds inhibited progesterone- and prostaglandin E1-induced hyperactivated sperm motility. One of the hit compounds is a potent CatSper inhibitor with high selectivity for CatSper over hCav1.2, hNav1.5, moderate selectivity over hSlo3 and hERG, and low cytotoxicity and is therefore the most promising inhibitor identified in this study. These new CatSper blockers serve as useful starting points for chemical probe development and drug discovery efforts.     

Solute-solvent interactions in micellar electrokinetic chromatography. 6. Optimization of the selectivity of lithium dodecyl sulfate-lithium perfluorooctanesulfonate mixed micellar buffers

The optimization of the composition of mixed surfactants used as micellar electrokinetic chromatography (MEKC) pseudostationary phases is proposed as an effective method for the separation of complex mixtures of analytes. The solvation parameter model is used to select two surfactants (lithium dodecyl sulfate, LDS, and lithium perfluorooctanesulfonate, LPFOS) with contrasting solvation properties. Combination of these two surfactants allows variations of the solvation properties of MEKC pseudostationary phase along a wide range. Thus, the convenient variation of the proportion of both surfactants allows an effective control of the selectivity in such systems. An algorithm that predicts the overall resolution of a given mixture of compounds is described and applied to optimize the composition of the mixed surfactant for the separation of the mixture. The algorithm is based on the calculation of peak purities on simulated chromatograms as a function of the composition of the mixed LDS/LPFOS micellar buffer from data at several micellar buffer compositions. Successful separations were achieved for mixtures containing up to 20 compounds, in less than 12 min.     

Effect of two organic amendments on norflurazon retention and release by soils of different characteristics

The influence of two organic amendments on norflurazon sorption-desorption processes in four soils with very different physicochemical characteristics was studied in laboratory experiments to evaluate the potential leaching of this pesticide through organic fertilized soils. Sorption-desorption experiments were performed on original soils and on a mixture of these soils with urban waste compost (SUW) and a commercial amendment from olive-mill wastes (OW), at a rate of 6.25% (w/w). These mixtures were used immediately after preparation and after aging for 2 months. Norflurazon was analyzed by using a HPLC method. Norflurazon retention in original soils was related not only to the organic matter (OM) content but also to mineral surfaces present in soils. Norflurazon sorption increases largely after amendment in soils with low OM content, but the addition of exogenous OM to soils with medium OM content and/or other available adsorptive surfaces did not significantly affect norflurazon sorption. Even in some cases pesticide sorption decreases, due to the blocking of the mineral and organic soil surfaces with the amendment added. Transformation of exogenous OM during incubation depends both on the amendment added and on the type of soil and can affect sorption-desorption behavior of the soils surfaces in different manner, due to the modification of their hydrophobic-hydrophilic characteristics. Norflurazon desorption from original soils showed hysteresis in all cases, but it was not affected or even decreased in amended soils. It was a nonexpected behavior, especially in sandy soil, since it is generally assumed that a higher sorption always implies a lower mobility in soils. Norflurazon sorption must be taking place on very low affinity sites on exogenous OM through weak bindings, from which the pesticide can be easily desorbed. The application to soils of the organic amendments used in the present study could not be accepted to reduce norflurazon losses due to leaching processes.     

Attitudes Toward Giving Smoking Cessation Advice Among Nursing Staff at a Long-Term Residential Care Facility.

The objective of this study was to provide a first assessment of (a) long-term care staffs' prevalence of and attitudes toward giving smoking cessation advice to residents and (b) predictors of advice giving. Results of a survey (N = 115) found that 54.8% of licensed nurses and 34.6% of nursing assistants reported ever advising. Advising was associated with job classification and believing that residents' problem lists should include smoking. Not advising was associated with believing advice is the physicians' responsibility. Staff somewhat endorsed risks of smoking and benefits of cessation for residents, smoking as a right and pleasure, and that some residents cannot make decisions about smoking. Staff moderately endorsed safety concerns: 36% wanted policy changes. Lack of institutional support and perceived residents' cessation disinterest were key barriers. The findings suggest that staff may be missing intervention opportunities and that institutional support of advising cessation may facilitate maintenance and improvement of nursing home residents' health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does Class Size in First Grade Relate to Children's Academic and Social Performance or Observed Classroom Processes?

This study evaluated the extent to which first-grade class size predicted child outcomes and observed classroom processes for 651 children (in separate classrooms). Analyses examined observed child-adult ratios and teacher-reported class sizes. Smaller classrooms showed higher quality instructional and emotional support, although children were somewhat less likely to be engaged. Teachers in smaller classes rated typical children in those classes as more socially skilled and as showing less externalizing behavior and reported more closeness toward them. Children in smaller classes performed better on literacy skills. Larger classrooms showed more group activities directed by the teacher, teachers and children interacted more often, and children were more often engaged. Lower class sizes were not of more benefit (or harm) as a function of the child's family income. First-grade class size in the range typical of present-day classrooms in the United States predicts classroom social and instructional processes as well as relative changes in social and literacy outcomes from kindergarten to first grade. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Factors that Affect the Enzymatic Degradation of Natural Starch Granules -Effect of the Size of the Granules

In this study the relationship between the enzymatic susceptibility and the size of the corn and cassava starch granules was studied. The starch granules were separated by size and classified according to their average diameter in: a) larger than 16 urn: b) between 15 and 10 um and c) smaller than 10 um. The starch granules of various sizes were hydrolyzed by bacterial alpha-amylase and fungal amyloglucosidase. The results showed a relationship between the enzymatic susceptibility and the size of the starch granules: smaller size of the starch granules resulted in a higher percentage of hydrolysis. A basic difference in the mode of action of enzymes on small and large granules was observed. Enzymatic attack on the large granules was characterized by considerable surface corrosion, mainly at the radial axis. For small granules, the enzymatic action occurred on the surface of the granules and was characterized by an erosion with solubilization of the granules. Chemical and physical analysis of the starches suggested that hydrolysis should occur mainly at the amorphous areas of the granules.     

Effect of Aphidicolin,a Reversible Inhibitor of Eukaryotic Nuclear DNA Replication,on the Production of Genetically Modified Porcine Embryos by CRISPR/Cas9

Mosaicism is the most important limitation for one-step gene editing in embryos by CRISPR/Cas9 because cuts and repairs sometimes take place after the first DNA replication of the zygote. To try to minimize the risk of mosaicism, in this study a reversible DNA replication inhibitor was used after the release of CRISPR/Cas9 in the cell. There is no previous information on the use of aphidicolin in porcine embryos, so the reversible inhibition of DNA replication and the effect on embryo development of different concentrations of this drug was first evaluated. The effect of incubation with aphidicolin was tested with CRISPR/Cas9 at different concentrations and different delivery methodologies. As a result, the reversible inhibition of DNA replication was observed, and it was concentration dependent. An optimal concentration of 0.5 μM was established and used for subsequent experiments. Following the use of this drug with CRISPR/Cas9, a halving of mosaicism was observed together with a detrimental effect on embryo development. In conclusion, the use of reversible inhibition of DNA replication offers a way to reduce mosaicism. Nevertheless, due to the reduction in embryo development, it would be necessary to reach a balance for its use to be feasible.