Microstructural Characterization and Magnetic, Dielectric, and Transport Properties of Hydrothermal La2FeCrO6 Double Perovskites.

Double perovskite La2FeCrO6 (LFCO) powders were synthesized via the hydrothermal method, which crystallized in an orthorhombic (Pnma) structure and exhibited a spherical morphology with an average particle size of 900 nm. Fourier transform infrared spectroscopy demonstrated the presence of fingerprints of vibrational modes of [FeO6] and [CrO6] octahedra in the powders. The XPS spectra revealed dual oxide states of Fe (Fe2+/Fe3+) and Cr (Cr3+/Cr4+) elements, and the oxygen element appeared as lattice oxygen and defect oxygen, respectively. The LFCO powders exhibited weak ferromagnetic behavior at 5 K with a Curie temperature of 200 K. Their saturation magnetization and coercive field were measured as 0.31 µB/f.u. and 8.0 kOe, respectively. The Griffiths phase was observed between 200 K and 223 K. A butterfly-like magnetoresistance (MR)-magnetic field (H) curve was observed in the LFCO ceramics at 5 K with an MR (5 K, 6 T) value of -4.07%. The temperature dependence of resistivity of the LFCO ceramics demonstrated their semiconducting nature. Electrical transport data were fitted by different conduction models. The dielectric behaviors of the LFCO ceramics exhibited a strong frequency dispersion, and a dielectric abnormality was observed around 260 K. That was ascribed to the jumping of electrons trapped at shallow levels created by oxygen vacancies. The dielectric loss showed relaxation behavior between 160 K and 260 K, which was attributed to the singly ionized oxygen vacancies.

Observation of the Systolic Function of Isolated Right Atria from Guinea Pigs.

Common chronic heart failure (CHF) is characterized by impaired ventricular filling and/or ejection function, which leads to insatiable cardiac output and increased incidence. The decline in cardiac systolic function is a key factor in the pathogenesis of CHF. Systolic function is simply the filling of oxygenated blood in the left ventricle, followed by the blood being pumped throughout the body during a heartbeat. A weak heart and the inability of the left ventricle to contract appropriately as the heart beats indicate poor systolic function. Many traditional herbs have been suggested to strengthen the systolic function of the heart in patients. However, stable and efficient experimental methods for screening compounds that enhance myocardial contractility are still lacking in the process of ethnic medicine research. Here, taking digoxin as an example, a systematic and standardized protocol is provided for screening compounds that enhance myocardial contractility by using isolated right atria from guinea pigs. The results showed that digoxin could markedly enhance the contractility of the right atrium. This systematic and standardized protocol is intended to serve as a methodological reference for screening the active ingredients of ethnic medicines in the treatment of CHF.

Microstructural Characterization of the Sol-Gel-Derived Sr2CrReO6 Powders and Their Magnetic and Electrical Transport Properties.

The double-perovskite (DP) Sr2CrReO6 (SCRO) oxide has gained much attention due to its high Curie temperature (∼635 K), high spin polarization, and strong spin-orbit coupling, which provides promising potential for room-temperature spintronic devices. In this work, we report on microstructures of a set of sol-gel-derived SCRO DP powders and their magnetic and electrical transport properties. The SCRO powders crystallize into a tetragonal crystal structure (space group of I4/m). X-ray photoemission spectroscopy spectra verify that the rhenium ions possess variable valences (Re4+ and Re6+) in the SFRO powders while chromium ions are presented as Cr3+. Ferrimagnetic behavior was observed in the SFRO powders at 2 K, and the saturation magnetization was evaluated to be 0.72 µB/f.u. and the coercive field to be 7.54 kOe. The Curie temperature was derived from susceptibility measurements to be 656 K at 1 kOe. Such ferrimagnetic behavior stems from the Cr3-Re4+(Re6+) super exchange interaction via intervening oxygen. Electrical transport measurements revealed that the SFRO ceramic grains were semiconducting and the electrical transport process was governed by the small polarons hopping with variable ranges. The hopping paths for these small polarons are provided by the hetero-valent Re ions in the SCRO ceramics. Negative magnetoresistance (MR) was observed in the SCRO ceramics, and the plot of MR vs magnetic field (H) exhibited a butterfly-like shape. The MR (2 K, 6 T) was measured to be -5.3%, due to the intergranular magneto-tunneling effect. The present results demonstrate a unique combination of high-temperature ferrimagnetism and intrinsic semiconducting nature of the sol-gel-derived SCRO oxides, which are highly attractive for oxide spintronics.

B-Site Fe/Re Cation-Ordering Control and Its Influence on the Magnetic Properties of Sr2FeReO6 Oxide Powders.

Double-perovskite oxide Sr2FeReO6 (SFRO) powders have promising applications in spintronics due to their half-metallicity and high Curie temperature. However, their magnetic properties suffer from the existence of anti-site defects (ASDs). Here, we report on the synthesis of SFRO powders by the sol-gel process. The B-site cationic ordering degree (η) and its influence on magnetic properties are investigated. The results demonstrate that the η value is well controlled by the annealing temperature, which is as high as 85% when annealing at 1100 °C. However, the annealing atmospheres (e.g., N2 or Ar) have little effect on the η value. At room temperature, the SFRO powders crystallize in a tetragonal crystal structure (space group I4/m). They have a relatively uniform morphology and the molar ratios of Sr, Fe, and Re elements are close to 2:1:1. XPS spectra identified that Sr, Fe, and Re elements presented as Sr2+, Fe3+, and Re5+ ions, respectively, and the O element presented as O2-. The SFRO samples annealed at 1100 °C in N2, exhibiting the highest saturation magnetization (MS = 2.61 µB/f.u. at 2 K), which was ascribed to their smallest ASD content (7.45%) with an anti-phase boundary-like morphology compared to those annealed at 1000 °C (ASDs = 10.7%) or 1200 °C (ASDs = 10.95%).

Urinary concentration of personal care products and polycystic ovary syndrome: A case-control study.

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorder among females of reproductive age. Many emerging contaminants in personal care products have been confirmed with endocrine disruptive effects. We performed a case-control study to explore the association between the concentrations of certain emerging contaminants (organic UV filters, bisphenol A, and triclosan) and the risk of PCOS. Urine samples were collected from 40 women with PCOS (case group) and 83 healthy women (control group). No significant differences were found in detection rate or total concentrations of analytes in women with PCOS and controls (p > 0.05). In addition, no association was found between certain emerging contaminants and PCOS either in an unadjusted binary logistic regression model or in a model adjusted for potential confounders. However, with stratification according to body mass index, one organic UV filter - octocrylene(OC) was significantly associated with PCOS in women with BMI ≥ 24 (adjusted OR = 1.512, 95% CI: 1.043, 2.191). It's the first time to investigate the association between exposure of organic UV filters and PCOS risk. We conclude that there is positive association between OC and PCOS risk in obese and overweight women.

Organic UV filters in indoor dust and human urine: A study of characteristics, sources, associations and human exposure.

Organic ultraviolet (UV) filters are emerging contaminants that may pose health risks to humans. We measured the concentrations of four commonly used organic UV filters (2-hydroxy-4-methoxybenzophenone (BP-3), 4-methylbenzylidene camphor (4-MBC), homosalate (HMS), and octocrylene (OC)) in 203 indoor dust samples and 98 human urine samples from households in eastern China. The total concentrations of the four organic UV filters ranged from 66.6-56,123.0 ng g-1 in indoor dust and 1.17-52.15 µg g-1 (creatinine-adjusted concentration (Cr)) in urine. BP-3 was the most abundant organic UV filter in the urine samples (median concentration: 1.89 µg g-1 Cr), while OC was the most abundant in the indoor dust samples (median concentration: 325.7 ng g-1). No significant correlations were found between organic UV filter concentrations in paired urine and dust samples, but the concentrations of UV filters in the indoor dust samples were positively correlated with family income and sunscreen use. The sources of the organic UV filters in the indoor dust samples differed based on the geographical location of the tested household. The fraction of human exposure to organic UV filters that resulted from ingestion or dermal absorption of indoor dust was close to 8%.

Three-dimensional cellulose based silver-functionalized ZnO nanocomposite with controlled geometry: Synthesis, characterization and properties.

Cellulose based Ag-functionalized ZnO nanocomposite (AZC) films were prepared using a green and easy scale-up strategy. Firstly, ZnO embedded cellulose (ZC) nanocomposite was synthesized from a cellulose-NaOH/zincate/urea solution through a biomimetic approach. Secondly, Ag nanoparticles (NPs) with a mean diameter of 53.2 nm were efficiently deposited onto the surface of embedded ZnO in cellulose matrix under UV irradiation (16 w), yielding the multi-hybrid AZC film. Owing to the porous structure of cellulose substrate and its rich hydroxyl group, the NPs in the ACZ films displayed good stability. Because of the formation of Schottky barriers in the Ag-ZnO regions, the catalytic activity of ACZ films increased by 20 times when compared to that of ZC sample. Furthermore, the AZC films could completely inhibit both S. aureus and E. coli growth. This facile and eco-friendly approach is expected to pave the way for constructing multifunctional cellulose material for various niche applications.

[Detecting genetic polymorphisms of CYP1 A1 and GSTM1 simultaneously with oligonucleotide microarray].

Cytochrome P4501A1 plays a major role in the bioactivation of a number of tobacco procarcinogens. Glutathione S-transferase( GSTM1), a member of the class of GST gene family, has been shown to be polymorphic because of gene deletion resulting in a failure to express the GSTM1 gene in 50% approximately 60% of individuals. Some CYP1 A1/GSTM1 null genotype combinations seem to predispose the lung, esophagus, and oral cavity of smokers to an even higher risk for cancer or DNA damage, requiring, however, confirmation. An easy and reliable oligonuleotide microarray approach validated through direct sequencing method is developed in order to accurately detect single nucleotide polymorphisms of CYP1 A1 gene and discriminate the presence and absence of GSTM1 gene. The m1 (Msp I) and m2 (Ile462Val) polymorphisms of CYP1 A1 gene and GSTM1 null genotype were also determined in a random population of 84 healthy, unrelated volunteers with developed microarray-based method. Of 84 cases, 47.6% were calssified as GSTM1 null, close to the published data. It's interesting that there lack three genotypes of m1 -m2 locus in the population: TT-AG, TT-GG and TC-GG. However, according to the data of the genotype frequencies independently happened at both m1 and m2 site, the combination frequencies of above three genotypes are 11.4%, 2.6%, and 3.1% respectively. Therefore we assume that the haplotypes of m1 -m2 are only T-A, C-A and C-G, but not T-G, as it were,there is no recombination happened between m1 site and m2 site. The frequencies of three haplotypes of T-A, C-A and C-G, calculated through corresponding genotypes, are 69.6%, 7.7% and 22.6% respectively.