What is the significance of the chloroform stabilizer C5H10 and its association with MeOH in concentration-dependent polymeric solutions?

The understanding of excitonic transitions associated with polymeric aggregates is fundamental, as such transitions have implications on coherence lengths, coherence numbers and inter- and intra-chain binding parameters. In this context, the investigation of efficient solvents and other ways to control polymer aggregate formation is key for their consolidation as materials for new technologies. In this manuscript, we use Poly(3-hexothiophene) (P3HT) as a probe to investigate the significance of amylene (C5H10) and its association with methanol (MeOH) in both pure and C5H10-stabilized chloroform (CHCl3)-based polymeric solutions. Using the intensity ratio between the first and second vibronic transitions of the P3HT H-aggregates formed, values for their exciton bandwidths and interchain interactions are obtained and correlated with the presence of C5H10 and MeOH as agents determining the CHCl3 quality.

Troubleshooting spectral artifacts from biplate retarders for reliable Stokes spectropolarimetry.

Polarimetry is generally used to determine the polarization state of light beams in various research fields, such as biomedicine, astronomy, and materials science. In particular, the rotating quarter-wave plate polarimeter is an inexpensive and versatile option used in several single-wavelength applications to determine the four Stokes parameters. Extending this technique to broadband spectroscopic measurements is of great scientific interest since the information on light polarization is highly sensitive to anisotropic phenomena. However, the need for achromatic polarizing elements, especially quarter-wave plates, requires special attention in their modeling. In this study, we implemented a rotating retarder spectropolarimeter for broadband measurements using a commercially available quasi-achromatic biplate retarder over the visible range. Here, we present a comprehensive approach for troubleshooting this type of spectropolarimeter through the observation of artifacts stemming from the standard single-plate retarder model. Then, we derive a more suitable model for a quasi-achromatic retarder consisting of a biplate junction. This new biplate model requires knowledge of the intrinsic dispersive properties of the biplate, namely the equivalent retardance, fast axis tilt, and rotatory angle. Hence, in this study, we also show a self-consistent methodology to determine these biplate properties using the same polarimeter apparatus so that accurate Stokes parameters can be determined independently. Finally, the comparison of data generated with the standard single-plate and new biplate models shows a significant improvement in the measurement precision of the investigated polarization states, which confirms that remodeling the retarder for reliable spectropolarimetry is necessary.

Effects of Particle Size Distribution of Standard Sands on the Physical-Mechanical Properties of Mortars.

Obtained natural sands can present different particle size distributions (PSD), although they have the same mineralogical origin. These differences directly influence the physical and mechanical behavior of mortars and, therefore, the performance of mortar and ceramic renderings. Standardizing the particle size of sands based on pre-established requirements in normative standards (NBR 7214 or ASTM C778) is one way to minimize these effects. However, these standards do not consider the optimization of the granular skeleton through the analysis of bulk density and PSD, which may be insufficient to obtain satisfactory results. Therefore, this paper analyzes the effects of using different particle size ranges on the physical and mechanical behavior of cement and hydrated lime mortars. The properties of consistency index, bulk density, air content, capillary water absorption, water absorption by immersion, flexural strength, compressive strength, and dynamic modulus of elasticity were evaluated. For this purpose, standardized sands of the same mineralogical origin were made with different particle size ranges, being: (i) standardized sand constituted by 25% of coarse and fine fractions (S25-control), (ii) standardized sand constituted by 30% of coarse fraction and 20% of fine fraction (S30-20), and (iii) standardized sand composed by 40% of coarse fraction, and 10% of fine fraction (S40-10), respectively. The results indicated that variations in the particle size composition of the standardized sands are necessary to obtain mixtures with higher compactness and, therefore, mortars with better physical and mechanical performance. Thus, the dosage of the particle size fractions of standardized sand should consider the optimization of the granular skeleton, being the unit mass and the granulometric composition as important parameters to meet this premise.

Carnauba straw powder treated with bentonite for copper adsorption in aqueous solution: isothermal, kinetic and thermodynamic study.

In this work, the natural and modified carnauba powder from the addition of bentonite was evaluated for the adsorption of Cu(II) ions in synthetic solution. The results showed that the carnauba powder treated with bentonite (CPTB) showed a better percentage of removal of Cu(II) ions when compared to natural carnauba powder (NCP). The best results for both adsorbents were obtained with pH 5. The adsorption kinetics was governed by the pseudo-second-order model for both bioadsorbents studied. While the isothermal behavior was governed by the Langmuir model and showed that the adsorption capacity of the CPTB for Cu(II) was 21.98 mg·g-1. The interaction of the metal and CPTB was also investigated by means of thermodynamic parameters showing that the adsorption process is not spontaneous, although the values of ΔG° decrease with the increase in temperature from 20 to 40 °C and endothermic causing an increase in the degree of disorder at the solid/liquid interface. The results showed that the CPTB is a material with potential adsorbent for the removal of copper ions.

[Relationship between overweight/obesity and hypertension among adults in China: a prospective study].

OBJECTIVE: To evaluate the influence of overweight/obesity on the incidence of hypertension among adults in China. METHODS: The subjects of this prospective study were 13 739 Chinese adults aged 35-74 years recruited at the baseline surveys of China Multicenter Collaborative Study of Cardiovascular Disease Epidemiology and International Collaborative Study of Cardiovascular Disease in Asian. Baseline surveys were conducted in 1998 and during 2000-2001, respectively, and the follow-up was conducted during 2007-2008. According to the body mass index, the subjects were divided into four groups: underweight group(<18.5 kg/m(2)), normal weight group(18.5-23.9 kg/m(2)), overweight group(24.0-27.9 kg/m(2))and obesity group(≥28.0 kg/m(2)). Age-standardized cumulative incidence of hypertension was calculated for each group, respectively. The relative risks(RRs)and 95% confidence intervals(CIs)for the incidence of hypertension of underweight, overweight and obesity groups were estimated by using generalized linear regression model with normal weight group as reference. RESULTS: During 8.1 years of follow-up, 4 271 hypertension cases were detected(2 012 in men and 2 259 in women). Age-standardized cumulative incidence of hypertension for the underweight, normal weight, overweight and obesity groups were 20.3%, 30.9%, 43.6% and 50.8% in men, respectively; and 22.9%, 30.4%, 41.1% and 50.8% in women, respectively. Compared with the normal weight group, multivariate-adjusted RR(95% CI)for the incidence of hypertension in underweight, overweight and obesity groups were 0.78(0.64-0.95), 1.22(1.13-1.30)and 1.28(1.16-1.42)in men, respectively; and 0.89(0.77-1.03), 1.16(1.09-1.23)and 1.28(1.18-1.38)in women, respectively. The overweight and obese subjects had higher risk for the incidence of hypertension, with the population attributable risk proportion of 7.4% in men and 8.8% in women, respectively. CONCLUSION: Overweight or obese people are at an increased risk of developing hypertension, thus prevention and control of overweight/obesity are needed to reduce hypertension incidence among adults in China.

Tissue distribution, expression, and antimicrobial activity of Anas platyrhynchos avian ß-defensin 6.

In this study, a novel avian ß-defensin (AvBD) was isolated from the Chaohu duck. The complete nucleotide sequence of the gene contained a 204-bp open reading frame that encoded 67 amino acids (aa), including a signal peptide of 20 aa, a propiece of 5 aa, and a mature peptide of 42 aa. The homology, characterization, and comparison of this gene with AvBD from other avian species confirmed that it was duck AvBD6. Also, the preproprotein of AvBD6 from chicken, goose, and duck was highly conserved with 100% aa homology. The AvBD6 mRNA was widely expressed in the investigated tissues of healthy 5-mo-old ducks, with the exception of the skin, kidney, and bursa. The AvBD6 mRNA was highly expressed in the spleen, lung, stomach, tongue, and egg yolk, successively; moderately expressed in the bone marrow and liver; and expressed to lower degrees in the trachea, heart, intestine, muscle, esophagus, and testis. We produced recombinant AvBD6 by expressing the gene in Escherichia coli. The yield of soluble glutathione S-transferees (GST)-AvBD6 in the inclusion bodies increased significantly as the incubation temperature was decreased from 37 to 30°C. As expected, the GST-AvBD6 exhibited strong bactericidal properties [minimum inhibitory concentration (MIC) = 0.5 to 2 µM] against the Aeromonas veronii biovar sobria strain BJCP-5, E. coli, and Enterococcus faecalis [ATCC 29212); it possessed medium bactericidal properties (MIC = 4 to 8 µM) against Staphylococcus aureus, Salmonella enteritidis, Pseudomonas aeruginosa (ATCC 27853), and Bacillus subtilis (CMCC 63501;; and it possessed low bactericidal properties (MIC = 16 µM) against Candida albicans (ATCC 10231). Additionally, the antimicrobial activity of GST-AvBD6 proved to be the same as that of synthetic AvBD6. The A. veronii biovar sobria strain BJCP-5 cells that were treated with GST-AvBD6 showed lysis and shrinkage under scanning electron microscopy. The mechanisms of AvBD6-mediated killing of A. veronii biovar sobria involved both cell lysis and nonlysis. Our results indicate that AvBD6 plays an important role in the innate immunity of the Chaohu duck.