Dielectric relaxation and conduction mechanism in Aurivillius ceramic Bi5Ti3FeO15

For this study, we synthesized Aurivillius Bi5Ti3FeO15 ceramic using the generic solid-state reaction route and then performed room-temperature X-ray diffraction to confirm that the compound had a single phase with no impurities. The surface morphology of the prepared sample was observed to contain microstructural grains approximately 0.2–2 μm in size. The dielectric properties of the sample were determ-ined as a function of frequency in a range of approximately 100 Hz to 1 MHz at various temperatures (303 K ≤ T ≤ 773 K). Nyquist plots of the impedance data were found to exhibit a semi-circular arc in the high-temperature region, which is explained by the equivalent electrical circuit (R1C1)(R2QC2), where R1 and R2 represent the resistances associated with the grains and grain boundaries, respectively, C1 and C2 are the re-spective capacitances, and Q is the constant phase element (CPE), which accounts for non-Debye type of behavior. Our results indicate that both the resistance and capacitance of the grain boundaries are more prominent than those of the grains. The alternating current (ac) conductiv-ity data were analyzed based on the Jonscher universal power law, which indicated that the conduction process is dominated by the hopping mechanism. The calculated activation energies of the relaxation and conduction processes were very similar (0.32 to 0.53 eV), from which we conclude that the same type of charge carriers are involved in both processes.     

Effect of Co substitution on the structural,dielectric and optical properties of KBiFe2O5

Cobalt (Co)-modified brownmillerite KBiFe2O5 (KBFO; [KBiFe2(1?x)Co2xO5 (x = 0, 0.05)]) polycrystalline is synthesized following the solid-state reaction route. Rietveld refinement of X-ray diffraction data confirmed the phase purity of KBFO and KBiFe1.9Co0.1O5 (KBFCO). The optical bandgap energy (Eg) of KBFO decreased from 1.59 to 1.51 eV because of Co substitution. The decrease in bandgap can be attributed to the tilting of the Fe–O tetrahedral structure of KBFCO. The observed room-temperature Raman peaks of KBFCO shifted by 3 cm?1 toward a lower wavenumber than that of KBFO. The shift in Raman active modes can be attributed to the change in the bond angles and bond lengths of the Fe–O tetrahedral structure and modification in response to oxygen deficiency in KBFO because of Co doping. Compared with that of KBFO, the frequency-dependent dielectric constant and dielectric loss of KBFCO decrease at room temperature, which is a con-sequence of the reduction in oxygen migration and modification in response to vibrational modes present in the sample.     

发展中国家的历史文化名城保护

发展中国家的历史文化名城保护纳吉波②（东南大学建筑系，南京２１００１８）由于各国文化背景和经济建设状况不同，对历史文化遗产的保护在时间和深度上都存在差异．发达国家对历史文化遗产的保护较早，特别是保护那些保留了整个地区文物建筑及历史风貌的城镇，从而形...     

Mutations in different components of FGF signaling in LADD syndrome

Lacrimo-auriculo-dento-digital (LADD) syndrome is characterized by lacrimal duct aplasia, malformed ears and deafness, small teeth and digital anomalies. We identified heterozygous mutations in the tyrosine kinase domains of the genes encoding fibroblast growth factor receptors 2 and 3 (FGFR2, FGFR3) in LADD families, and in one further LADD family, we detected a mutation in the gene encoding fibroblast growth factor 10 (FGF10), a known FGFR ligand. These findings increase the spectrum of anomalies associated with abnormal FGF signaling.     

Bilirubin sensor based on CuO-CdO composites deposited in a nafion/glassy carbon electrode matrixes

Copper oxide-cadmium oxide nanocomposites(CuO-CdO NCs) were synthesized by solvothermal technique in a basic medium. CuO-CdO NCs were characterized using conventional techniques, such as Fourier Transform Infrared Spectroscopy(FTIR), UV–Visible Spectroscopy(UV/Vis), Field-Emission Scanning Electron Microscopy(FESEM), X-ray electron dispersive spectroscopy(XEDS), X-ray photoelectron spectroscopy(XPS), and powder X-ray diffraction(XRD). A selective and enzyme-less Bilirubin(BLR) sensor was developed with a thin-layer of NCs onto a glassy carbon electrode(GCE, surface area = 0.0316 cm~2) using 5% nafion binders at room conditions. Improved electrochemical performances of higher sensitivity, lower detection limit,linear dynamic range(LDR), and long-term stability of preferred BLR were achieved by a reliable currentvoltage(I-V) approach. The calibration curve was found linear(R~2= 0.9347) in a wide range of BLR concentration(10.0 pM ~ 10.0 mM). Based on the signal to noise ratio value of 3, the sensitivity and limit of detection(LOD) of the sensor were calculated as 95.0 pA μM~(-1) cm~(-2) and 1.0 ± 0.1 pM respectively.Solvothermally synthesized CuO-CdO NCs/GCE is an excellent advancement of developing a selective and sensitive BLR sensor by electrochemical approach and practically implemented in real sample applications.     

Loss-of-function variant in DNASE1L3 causes a familial form of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that causes substantial morbidity. As is typical for many other multifactorial disorders, much of the heritability of SLE remains unknown. We identified a rare autosomal recessive form of SLE, in which autozygome analysis revealed a null mutation in the DNASE1L3 gene. The DNASE1L3-related SLE we describe was always pediatric in onset and correlated with a high frequency of lupus nephritis. Our findings confirm the critical role of impaired clearance of degraded DNA in SLE pathogenesis.     

Mechanical properties and microstructure of composites produced by recycling metal chips

In this study, the processing and mechanical properties of porous metal matrix composites (MMCs) composed of spheroidal cast iron chips (GGG40) and bronze chips (CuSn10) and formed by hot isostatic pressing were investigated. Bronze chips (CuSn10) were used as a matrix component, and spheroidal cast iron (GGG40) chips were used as a reinforcement component. The MMCs were produced with different CuSn10 contents (90wt%, 80wt%, 70wt%, and 60wt%). The hot isostatic pressing process was performed under three different pressures and temperatures. The produced MMCs were characterized using density tests, Brinell hardness tests, and compression tests. In addition, the consolidation mechanism was investigated by X-ray diffraction (XRD) analysis and scanning electron microscopy. The test results were compared with those for bulk CuSn10 and bulk GGG40. Mechanical tests results revealed that the metallic chips can be recycled by using hot pressing and that the mechanical properties of the produced MMCs were similar to those of bulk CuSn10. XRD and microscopy studies showed that no intermetallic compounds formed between the metallic chips. The results showed that the CuSn10 and GGG40 chips were consolidated by mechanical interlocking.     

Mutations in SECISBP2 result in abnormal thyroid hormone metabolism

Incorporation of selenocysteine (Sec), through recoding of the UGA stop codon, creates a unique class of proteins. Mice lacking tRNA(Sec) die in utero, but the in vivo role of other components involved in selenoprotein synthesis is unknown, and Sec incorporation defects have not been described in humans. Deiodinases (DIOs) are selenoproteins involved in thyroid hormone metabolism. We identified three of seven siblings with clinical evidence of abnormal thyroid hormone metabolism. Their fibroblasts showed decreased DIO2 enzymatic activity not linked to the DIO2 locus. Systematic linkage analysis of genes involved in DIO2 synthesis and degradation led to the identification of an inherited Sec incorporation defect, caused by a homozygous missense mutation in SECISBP2 (also called SBP2). An unrelated child with a similar phenotype was compound heterozygous with respect to mutations in SECISBP2. Because SBP2 is epistatic to selenoprotein synthesis, these defects had a generalized effect on selenoproteins. Incomplete loss of SBP2 function probably causes the mild phenotype.     

Immobilization of cross-linked In-doped Mo(O,S)2 on cellulose nanofiber for effective organic-compound degradation under visible light illumination

Relatively small amounts of In-doped Mo(O,S)₂ (IMS) catalysts (10%, 20%, and 30%) were deposited on cellulose nanofiber (CNF) by cross-linking them with functional groups of siloxane and epoxy to form CNF-IMS hybrid composites. The as-prepared hybrid composites were characterized and tested their performances toward the photo degradations of cationic (MB and RhB) and anionic (MO) dyes. As indium was doped into Mo(O,S)₂ lattice to form solid-solution, the charge transfer and photocarrier separation during the catalytic reaction were simultaneously enhanced as probed with electrochemical impedance spectroscopy and photoluminescence measurements, respectively. To ensure the catalyst on CNF was well deposited and recyclable, the hybrid composite was evaluated with a reusability experiment to show the stability performance in degrading organic dyes. It was found the environmentally friendly CNF-IMS hybrid composite was relatively stable during the reusability experiment, indicating no catalyst powder was leached out during the photocatalytic reaction. The photoreaction mechanism was convinced by radical-scavenging experiments to show that hydroxyl and superoxide played essential roles for the organic dye degradations in visible-light illuminated conditions. The cross-linked organic/inorganic hybrid catalyst showed a prospective visible light active material not only to solve the environmental issue due to the leaching of nanoparticles but also to lower the post-treatment/recycling cost of photocatalyst in industrial application.