ALBERT

Description: Ultralight Si 3 N 4 ceramic foams have been successfully prepared through particle-stabilized foams method, which is based on the adsorption of in situ hydrophobized Si 3 N 4 particles to the liquid/air interface of the foams. Here, we firstly used a long-chain surfactant cetyltrimethylammonium chloride to render the Si 3 N 4 particles partially hydrophobic. By tailoring the surfactant concentration and pH values of the suspensions, the wet foams were stabilized to avoid coarsening and coalescence. SEM results show that the Si 3 N 4 ceramic foams possess single strut walls with elongated β-Si 3 N 4 grains interlocking with each other, and their pores are uniform with an average pore size of 95 μm. The obtained ceramic foams maintain compressive strength of 1.34 ± 0.13 MPa with porosity of 92.0%, when the suspension contains 3 mmol/L surfactant at the pH of 11.0.

Description: Abstract The electrical behavior of iron‐doped strontium titanate (Fe:SrTiO3) single crystals equilibrated at 900°C and quenched below 400°C at various oxygen partial pressures () was investigated via impedance spectroscopy and compared to defect chemistry models. Fe:SrTiO3 annealed and quenched between 1.2 × 10−14 and 2.0 × 10−4 Pa exhibits a conduction activation energy (EA) around 0.6 eV, consistent with ionic conduction of oxygen vacancies. However, sudden changes in EA are found to either side of this range; a transition from 0.6 to 1 eV is found in more oxidizing conditions, while a sudden transition to 1.1 and then 0.23 eV is found in reducing These transitions, not described by the widely used canonical model, are consistent with predictions of transitions from ionic to electronic conductivity, based on first principles point defect chemistry simulations. These models demonstrate that activation energies in mixed conductors may not correlate to specific conduction mechanisms, but are determined by the cumulative response of all operative conduction processes and are very sensitive to impurities. A comparison to electrically degraded Fe:SrTiO3 provides insight into the origins of the conductivity activation energies observed in those samples.

Description: Methyl pothoscandensate ( 1 ), a new molecular skeleton of ent -18(4→3)-abeokaurane, along with eight known compounds was isolated from the whole plant of Pothos scandens. The structure of the new compound was established by spectroscopic techniques and confirmed by single-crystal X-ray diffraction. The inhibitory activity of selected compounds against porcine respiratory and reproductive syndrome virus (PRRSV) was measured by the cytopathic effect (CPE) method. Compound 1 showed weak effect on PRRSV with an IC 50 value of 40.3±8.3 μ M ( TI =15.7).

Description: In spring 2013, thirty-three repeat shipboard Acoustic Doppler Current Profile (ADCP) surveys were conducted to measure the tidal current in the Qiongzhou Strait (QS). The major tidal currents and the residual current along a section across the QS were estimated using a modified tidal harmonic analysis method based on the inverse technique. A simple simulation and comparisons with previous observations demonstrated that the tidal currents estimated using the modified tidal harmonic analysis method are reasonable, and this method was able to control the magnitude and deviation of the estimation error. The direction of the major axis of tidal current ellipses is generally along the strait. Diurnal tidal constituents are dominant among the five tidal current constituents ( K 1 , O 1 , M 2 , S 2 and MSf ). The ratio of the amplitudes of O 1 , K 1 , M 2 , S 2 and MSf , averaged along the section across the QS is 1:0.79:0.42:0.27:0.29. The residual current along the entire section is all westward; the averaged velocity over the section is 6.0±2.1 cm s -1 ; the associated volume transport through the section is -0.065±0.046 Sv (Sv=10 6 ×m 3 s -1 ), in which the second value denotes the uncertainty of first value. Dynamic analysis indicates that tidal current activity is more dominant than mean current and eddy activity, and tidal rectification and sea level difference between two entrances of the QS are important in maintaining the residual current through the strait.

Description: ABSTRACT Glycogen synthase kinase (GSK)-3β, a serine/threonine kinase with an inhibitory role in glycogen synthesis in hepatocytes and skeletal muscle, is also expressed in cardiac and smooth muscles. Inhibition of GSK-3β results in cardiac hypertrophy through reducing phosphorylation and increasing transcriptional activity of myocardin, a transcriptional co-activator for serum response factor. Myocardin plays critical roles in differentiation of smooth muscle cells (SMCs). This study therefore aimed to examine whether and how inhibition of GSK-3β regulates myocardin activity in human vascular SMCs. Treatment of SMCs with the GSK-3β inhibitors AR-A014418 and TWS 119 significantly reduced endogenous myocardin activity, as indicated by lower expression of myocardin target genes (and gene products), CNN1 (calponin), TAGLN1 (SM22) and ACTA2 (SM α-actin). In human SMCs overexpressing myocardin through the T-REx system, treatment with either GSK-3β inhibitor also inhibited the expression of CNN1, TAGLN1 and ACTA2. These effects of GSK-3β inhibitors were mimicked by transfection with GSK-3β siRNA. Notably, both AR-A014418 and TWS 119 decreased the serine/threonine phosphorylation of myocardin. The chromatin immunoprecipitation assay showed that AR-A014418 treatment reduced myocardin occupancy of the promoter of the myocardin target gene ACTA2. Overexpression of a dominant-negative GSK-3β mutant in myocardin-overexpressing SMCs reduced the expression of calponin, SM22 and SM α-actin. As expected, overexpression of constitutively-active or wild-type GSK-3β in SMCs without myocardin overexpression increased expression of these proteins. In summary, our results indicate that inhibition of GSK-3β reduces myocardin transcriptional activity, suggesting a role for GSK-3β in myocardin transcriptional activity and smooth muscle differentiation. This article is protected by copyright. All rights reserved

Description: Plants may affect the performance of neighboring plants either positively or negatively through interspecific and intraspecific interactions. Productivity of mixed-species systems is ultimately the net result of positive and negative interactions among the component species. Despite increasing knowledge of positive interactions occurring in mixed-species tree systems, relatively little is known about the mechanisms underlying such interactions. Based on data from 25-year-old experimental stands in situ and a series of controlled experiments, we test the hypothesis that a broadleaf, non-N fixing species, Michelia macclurei, facilitates the performance of an autotoxic conifer Chinese fir ( Cunninghamia lanceolata ) through belowground chemical interactions. Chinese fir roots released the allelochemical cyclic dipeptide (6-hydroxy-1,3-dimethyl-8-nonadecyl-[1,4]-diazocane- 2,5-diketone) into the soil environment, resulting in self-growth inhibition, and deterioration of soil microorganisms that improve P availability. However, when grown with M. macclurei the growth of Chinese fir was consistently enhanced. In particular, Chinese fir enhanced root growth and distribution in deep soil layers. When compared with monocultures of Chinese fir, the presence of M. macclurei reduced release and increased degradation of cyclic dipeptide in the soil, resulting in a shift from self-inhibition to chemical facilitation. This association also improved the soil microbial community by increasing arbuscular mycorrhizal fungi, and induced the production of Chinese fir roots. We conclude that interspecific interactions are less negative than intraspecific ones between non-N fixing broadleaf and autotoxic conifer species. The impacts are generated by reducing allelochemical levels, enhancing belowground mutualisms, improving soil properties, and changing root distributions as well as the net effects of all the processes within the soil. In particular, allelochemical context alters the consequences of the belowground ecological interactions with a novel mechanism __ reduction of self-inhibition through reduced release and increased degradation of an autotoxic compound in the mixed-species plantations. Such a mechanism would be useful in reforestation programs undertaken to rehabilitate forest plantations which suffer from problems associated with autotoxicity. This article is protected by copyright. All rights reserved.

Description: Zirconia ceramic foams with ultra-high porosity of 96%–98% have been fabricated using sodium dodecyl sulfate (SDS) as the particle stabilizer of zirconia particles for the first time. The wet foams stabilized by zirconia particles are ultra-stable due to partially hydrophobic zirconia particles modified by SDS. Zirconia foams exhibit close cells with thin cell wall and small grain size. Increasing SDS concentration favors the foamability of the suspension, and further increases the porosity of ceramic foams. Zirconia ceramic foams with porosity of 98.1% have compressive strength of 0.26 ± 0.05 MPa. Decreasing solid loading leads to the porosity of ceramic foams. The compressive strength could be improved significantly by increasing the sintering temperature. Zirconia ceramic foams with porosity of 97.9% has low thermal conductivity of 0.027 ± 0.004 W·(m·K) −1 , which could be used as thermal insulation and refractory material.

Description: Three diiron and tetrairon azadithiolate complexes as models for the active site of [FeFe] hydrogenase were prepared. Reaction of complex Fe 2 (SCH 2 OH) 2 (CO) 6 and NH 2 CH 2 CH 2 CH 2 OCH 3 resulted in the diiron azadithiolate hexcarbonyl complex Fe 2 [(SCH 2 ) 2 NCH 2 CH 2 CH 2 OCH 3 ](CO) 6 ( 1 ) in moderate yield. Furthermore, treatment of complex 1 with mono phosphine ligand PPh 3 and diphosphine ligand Ph 2 PCH 2 CH 2 PPh 2 in the presence of decarbonylation reagent Me 3 NO · 2H 2 O yielded the phosphine-substituted azadithiolate complexes Fe 2 [(SCH 2 ) 2 NCH 2 CH 2 CH 2 OCH 3 ]CO) 5 (PPh 3 ) ( 2 ) and {Fe 2 [(SCH 2 ) 2 NCH 2 CH 2 CH 2 OCH 3 ](CO) 5 } 2 (Ph 2 PCH 2 CH 2 PPh 2 ) ( 3 ) respectively. The new complexes 1 – 3 were fully characterized by elemental analysis, IR, 1 H, 13 C, 31 P NMR spectroscopy and X-ray crystallography. It is worthy to note that the crystallographic studies show the unusual difference of the methoxypropanyl substituent on the N atom of complexes 1 and 2 , largely because of the affection of phosphine ligand PPh 3 . In addition, complex 1 was found to be a catalyst for H 2 production under electrochemical condition.

Description: Abstract The transition from breakup of Nuna (or ColuSmbia, 2.0–1.6 Ga) to assembly of Rodinia (1.0–0.9 Ga) is investigated by means of U–Pb and Lu–Hf data of detrital zircons from three Neoproterozoic meta‐sedimentary rocks in the Central Tianshan Block (CTB), NW China. These data yield six age peaks around 1.0 Ga, 1.13 Ga, 1.34 Ga, 1.4–1.6 Ga, 1.75 Ga and 2.6 Ga. Few zircons are detected between 2.0 and 2.5 Ga. The Paleoproterozoic to Neoproterozoic detrital zircons have Hf isotopic compositions (–22.1 to +13.0) similar to those of coeval magmatic rocks in the CTB, indicating a proximal provenance. These results, together with the geological evidence and the presence of 1.4 Ga orogenic granitoids in the CTB, rule out most cratons as the CTB sources but support a Fennoscandia ancestry. Zircon U–Pb ages and Hf isotopic compositions from the CTB and Fennoscandia suggest that, from 1.8 Ga to 1.4 Ga, the εHf(t) values increased towards more positive values, consistent with an exterior orogen characteristic that the lower crust was replaced by a juvenile arc crust. In contrast, from 1.4 Ga to 0.9 Ga, zircon εHf(t) values decreased to more negative values, reflecting an interior orogen, characterized by enhanced contribution of recycled crustal material from collided continental fragments. This marked shift most likely reflected a transition from breakup of Nuna to assembly of Rodinia, accomplished by a transformation from an exterior orogen to an interior one.