A supercritical carbon dioxide(Sc CO2) assisted phase inversion was developed to produce microporous poly(vinylidene fluoride)(PVDF) membranes whose morphology characteristics arise from both liquid-liquid demixing and solid-liquid demixing(crystallization). This result was confirmed by Fourier transform infrared spectroscopy(FTIR), from which both α and β crystals were found. As revealed by contact angle experiment, the PVDF membranes prepared via Sc CO2 assisted phase inversion were more hydrophobic compared with the control membrane produced via conventional immersionprecipitation technique. In particular, the sample with 15 wt% PVDF prepared at 45 °C and 13 MPa exhibited a contact angle of 142°, which was mainly caused by the multilevel micro- and nano- structure. The effects of polyethylene glycol(PEG), polyvinyl pyrrolidone(PVP) and lithium chloride(Li Cl) on the structures and crystal form were investigated. PVP promoted the formation of β phase crystal form, while PEG boosts the evolution of α phase. Li Cl restrained the crystallization degree of PVDF membrane under Sc CO2.
The flexibility of dynamic community structure isadopted to analyze the depressive resting-state functionalmagnetic resonance imaging （rfMRI） signals in order toimprove the accuracy of evaluating depression treatment. TherfMRI signals of each brain network were obtained by theindependent component correlation algorithm （ICA）. Dynamicfunctional connections were computed with sliding windowsand L1 norm. Then, the connections were used to calculatethe dynamic community structure via the community-detectionalgorithm. The result of structure＇s community assignment hasthe general character with the brain activity changing overtime. The flexibility index is one of traits of dynamiccommunity structure, meaning the number of times a regionchanges. In this study, 16 patients who achieved clinicalremission joined the experiment and were scanned before andafter treatment. Pair permutation tests compare the differenceof six brain networks＇ flexibility between pre-therapy and post-treatment. The results show that the distribution of theflexibility values declines in a default network and cognitivecontrol network between we-therapy and post-treatmentpatients with statistical difference. Therefore, flexibility is asuitable approach to accurately evaluate the depressiontreatment effect.
Mo ZhaoqiWang QiangTian ShuiYan RuiGeng JitingYao ZhijianLu Qing
A full solution method has been developed as a low cost process of YBa_2Cu_3O_(7-x)(YBCO) coated conductor fabrication.In this study,highly biaxially textured SrTiO_3 (STO) buffer layers were fabricated on LaAlO_3 (LAO) single crystal substrates by sol-gel method using metal alkoxides as the staring precursor materials.High quality YBCO superconducting film was then fabricated on STO-buffered LAO substrate by trifluoroacetic metalorganic deposition (TFA-MOD) method.For the YBCO superconducting film,only (001) diffraction peaks can be detected by XRD (X-ray diffraction) analysis with no other phases detectable.Especially,In- plane texture of YBCO film is improved compared to that of STO buffer layer from phi scans analysis,which indicates the self-epitaxy phenomenon explained by considering interracial energy.STO and YBCO films both show c-axis oriented grains growt.h and have uniform surface microstructure.A critical transition temperature, T_c(R=0) of 89.5 K and a critical current density of 2 mA/cm^2 (77 K,self-field) were obtained for a 0.2μm thick YBCO film on STO-buffered LAO substrate.No reaction between YBCO and STO was detected by XRD analysis.This full solution process may provide a promising low cost fabrication route for YBCO coated conductors on metal tape.
Bromophenols are a set of natural products widely distributed in seaweed, most of which exhibit interesting and useful biological activities. To develop a reliable and efficient synthetic route to these natural bromophenols, three of them, 3,4-dibromo-5-(2′-bromo-3′,4′- dihydroxy-6′-methoxymethyl- benzyl)-benzene-1,2-diol (compound 9), 3,4-dibromo-5-(2′-bromo-6′-ethoxy methyl-3′,4′-dihydroxybenzyl)- benzene-1,2-diol (compound 10), and 3-bromo-4-(3′-bromo-4′,5′-dihydroxy benzyl)-5-(ethoxymethyl)- benzene-1,2-diol (compound 14), isolated from red marine algae, have been synthesized in eight steps with an overall yield of 14.4%, 14.4%, and 18.2% respectively, via a practical approach employing bromination, Wolff-Kishner-Huang reduction and a Friedel-Crafts reaction as key steps. The protein tyrosine phosphatase 1B (PTP1B) inhibitory activities of the synthetic compounds were evaluated by the colorimetric assay. The results show that these compounds are moderate PTP1B inhibitors. The synthesis of these bromophenol derivatives makes in vivo studies of their structure-activity relationships and inhibition activity against PTP1B possible.
The ability of abscisic acid (ABA) to modulate positive interactions between Arabidopsis thaliana individuals under salinity stress was investigated using abi1-1 (insensitive to ABA), era1-2 (hypersen- sitive to ABA) mutant and wild type plants. The results showed that sensitivity to ABA affects relative interaction intensity (RII) between Arabidopsis thaliana individuals. The neighbor removal experiments also confirmed the role of phenotypic responses in linking plant-plant interactions and sensitivity to ABA. For abi1-1 mutants, the absolute value differences between neighbor removal and control of stem length, root length, leaf area, leaf thickness, flower density, above biomass/belowground biomass (A/U), photosynthetic rate, stomatal conductance, leaf water content and water-use efficiency were smaller than those of the wild type, while for era1-2 mutants, these absolute value differences were larger than those of the wild type. Thus, it is suggested that positive interactions between Arabidopsis thaliana individuals are at least partly modulated by different sensitivity to ABA through different physiological and phenotypic plasticity.
Objective:To investigate the effects of electro-acupuncture preconditioning on focal cerebral blood flow(CBF)in artery and vein of rats with middle cerebral artery occlusion(MCAO),and to provide experimental evidences for primary prevention of ischemic stroke.Method:Eighteen male Sprague-Dawley rats(two months old)were divided into 3 groups:electro-acupuncture preconditioning group(EA group),ischemia group(Is group)and Dazhui and Baihui sham group(six rats per group).The rats in the EA group were given electro-acupuncture preconditioning at Dazhui and Baihui with 2/15 density wave current for 30 minutes per day,5 days consecutively.After preconditioning,enhanced laser speckle contrast analysis was implemented to get false color images before making middle cerebral ischemia occlusion model.Then getting false color images two hours during ischemia by laser speckle contrast analysis again.Result:④Relative CBF in focal cortical artery:There were significant differences at every time point in EA group and Is group(P<0.01,P<0.05)comparing with that before occlusion respectively.Compared with that before ischemia,there was significant difference at 120 min after ischemia in sham group(P<0.05);compared with that at 30 min after occlusion,there was significant difference at every time point in EA group from the time point 60 min after occlusion;there was significant difference at every time point in EA group and Is group(P<0.05)comparing with sham group;Compared with sham group,there was significant difference at 30min and 60 min after ischemia in EA group(P<0.05).④Relative CBF in focal cortical vein:There was significant difference at every time point in sham group comparing with that before occlusion(P<0.05);compared with that before occlusion,there was significant difference from 45 min after occlusion in EA group(P<0.05);compared with that before occlusion,there was significant difference from 105 min after occlusion in sham group(P<0.05);there was significant difference at 120 min after occlusion comparing with 6
The effect of rare earth(RE) on Mo partitioning and resultant mechanical and microstructural behavior of a duplex stainless steel during hot working condition was investigated. It was found that RE effect was sensitive to temperature. At the high temperature, the development of dynamic recovery(DRV) in α phase was slowed down while the dynamic recrystallization(DRX) process in γ phase was accelerated by RE, whereby both work hardening rate(at low strain) and dynamic softening rate(at high strain) increased and moreover, the discrepancy on the hardness of the both phase reduced. Whereas at the low temperature, the effect of RE was opposite as compared with those in the high temperature. Mo partitioning analysis by EPMA indicated that RE enhanced the partitioning of Mo in α phase while reduced Mo concentration in γ phase at higher temperature whereby the mismatch between two phases could be improved indicated by the elimination of voids and cracks at α/γ interface, but it was contrary to that at the low temperature. Mo partitioning was believed to be an important cause for the RE effect on the differences of mechanical and microstructural behavior. Also this result provided a reasonable evidence for micro-alloying of RE in DSSs.
