一锅法制备高亲水聚偏氟乙烯-g-聚丙烯酸钠超滤膜及其抗蛋白质污染性能

以丙烯酸(AA)为单体、碱化聚偏氟乙烯(HPVDF)为基材,通过自由基接枝共聚与碱诱导沉淀相转化连续进行的“一锅法”过程,制备了高亲水性聚偏氟乙烯-g-聚丙烯酸钠(PVDF-g-PAAS)超滤膜(FAS)。探讨了聚合反应及相转化条件对FAS理化性质、微观形貌及蛋白质污染行为的影响规律。结果表明,随着接枝体系料比(AA/HPVDF)和料液比(w(HPVDF))的增大,FAS表面由平整变为褶皱,断面由指状孔向海绵状过渡。FAS系列的初始水接触角均低于60°,在10s内完全润湿,牛血清白蛋白(BSA)截留率大于90%。料比为6/12时得到的FAS12-6的AA接枝率最高,纯水通量达565.83L/(m^(2)·h),清洗通量恢复率达94.62%,4次循环后稳态通量衰减低于8%,干后再润湿的纯水通量恢复率达81.6%。

High-sensitive terahertz detection by parametric up-conversion using nanosecond pulsed laser

A high-sensitive terahertz detector operating at room temperature was demonstrated based on parametric upconversion.A nanosecond 1064-nm Nd:YAG laser was used to pump the parametric up-conversion detector and the upconversion from terahertz wave to NIR laser was realized in a lithium niobate crystal.The minimum detectable terahertz energy of 9 p J was realized with the detection dynamic range of 54 d B,which was three orders of magnitude higher than that of commercial Golay cell.The detectable terahertz frequency range of the detection system was 0.90 Thz–1.83 THz.Besides,the effects of pump energy and effective gain length on the detection sensitivity were studied in experiment.The results showed that higher pump energy and longer effective gain length are helpful for improving the detection sensitivity of parametric up-conversion detector.

Construction of an Hα diagnostic system and its application to determine neutral hydrogen densities on the Keda Torus eXperiment

A 10-channel Hα diagnostic system has been designed with the rapid response rate of 300 kHz, spatial resolution of about 40 mm, and overlap between adjacent channels of about 3%, and it has been implemented successfully on Keda Torus eXperiment(KTX), a newly constructed, reversed field pinch(RFP) experimental device at the University of Science and Technology of China(USTC). This diagnostic system is a very important tool for the initial KTX operations. It is compact,with an aperture slit replacing the traditional optical lens system. A flexural interference filter is designed to prevent the center wavelength from shifting too much as the increase of angle from vertical incidence. To eliminate the stray light,the interior of the system is covered with the black aluminum foil having a very high absorptivity. Using the Hαemission data, together with the profiles of electron temperature and density obtained from the Langmuir probe, the neutral density profiles have been calculated for KTX plasmas. The rapid response rate and good spatial resolution of this Hαdiagnostic system will be beneficial for many studies in RFP plasma physics.

Fast radial scanning probe system on KTX

A fast radial scanning probe system was constructed for the Keda Torus eXperiment(KTX)to measure the profiles of boundary plasma parameters such as floating potential,electron density,temperature,transport fluxes,etc.The scanning probe system is driven by slow and fast motion mechanisms,corresponding to the stand-by movement of a stepping motor and the fast scanning movement of a high-torque servo-motor,respectively.In fast scanning,the scanner drives the probe radially up to 20 cm at a maximum velocity of 4.0 m s-1.A noncontact magnetic grating ruler with a high spatial resolution of 5μm is used for the displacement measurement.New scanning probe can reach the center of plasmas rapidly.The comparison of plasma floating potential profiles obtained by a fixed radial rake probe and the single scanning probe suggests that the high-speed scanning probe system is reliable for measuring edge plasma parameter profiles on the KTX device.

Geomechanical properties will constrain CO_(2)injection into the lower Ordovician Rose Run sandstone deep saline reservoir,Appalachian Basin,Kentucky,USA

The Kentucky Geological Survey(KGS)1 Hanson Aggregates stratigraphic research well,Carter County,Kentucky,USA,was drilled to a total depth of 1474 m as a field-scale test of potential CO2 storage reservoir properties in the Central Appalachian Basin.Geomechanical properties of the Rose Run sandstone(upper Ordovician Knox group)were tested for its suitability as a storage reservoir.A 9.8-m thick section of the Rose Run was penetrated at 1000 m drilled depth and a whole-diameter core and rotary sidewall cores were taken.Average porosity and permeability measured in core plugs were 9.1%and 44.6 mD,respectively.Maximum vertical stress gradient calculated in the wellbore was 26 MPa/km.Wellbore fractures in dolomites underlying and overlying the Rose Run follow the contemporary N53E Appalachian Basin stress field.The Rose Run elastic geomechanical properties were calibrated to values measured in core plugs to evaluate its fracturing risk as a CO2 storage reservoir.Mean Young’s modulus and Poisson’s ratio values of the Rose Run were 45 GPa and 0.23,respectively,whereas Young’s modulus and Poisson’s ratio values were 77.1 GPa and 0.28,respectively,in the overlying Beekmantown dolomite,suggesting the Rose Run may fracture if overpressured during CO2 injection but be confined by the Beekmantown.Triaxial compressive strength measured in core plugs found the Rose Run and Beekmantown fractured at mean axial stresses of 156.5 MPa and 282.2 MPa,respectively,confirming the Beekmantown as suitable for confining CO2 injected into the Rose Run.A step-rate test was conducted in a mechanically-isolated 18.6-m interval bracketing the Rose Run.Static Rose Run reservoir pressure was 9.3 MPa,and fracture gradient under injection was 13.6 MPa/km,suggesting step-rate testing before CO2 injection,and subsequent pressure monitoring to ensure confinement.As the region around the KGS 1 Hanson Aggregates well is underpressured and adjacent to faulted Precambrian basement,further research is needed to evaluate its induced seismicity risk during CO2 injection.

Bioprinted constructs that simulate nerve-bone crosstalk to improve microenvironment for bone repair

Crosstalk between nerves and bone is essential for bone repair,for which Schwann cells(SCs)are crucial in the regulation of the microenvironment.Considering that exosomes are critical paracrine mediators for intercellular communication that exert important effects in tissue repair,the aim of this study is to confirm the function and molecular mechanisms of Schwann cell-derived exosomes(SC-exos)on bone regeneration and to propose engineered constructs that simulate SC-mediated nerve-bone crosstalk.SCs promoted the proliferation and differentiation of bone marrow mesenchymal stem cells(BMSCs)through exosomes.Subsequent molecular mechanism studies demonstrated that SC-exos promoted BMSC osteogenesis by regulating the TGF-βsignaling pathway via let-7c-5p.Interestingly,SC-exos promoted the migration and tube formation performance of endothelial progenitor cells.Furthermore,the SC-exos@G/S constructs were developed by bioprinting technology that simulated SC-mediated nerve-bone crosstalk and improved the bone regeneration microenvironment by releasing SC-exos,exerting the regulatory effect of SCs in the microenvironment to promote innervation,vascularization,and osteogenesis and thus effectively improving bone repair in a cranial defect model.This study demonstrates the important role and underlying mechanism of SCs in regulating bone regeneration through SC-exos and provides a new engineered strategy for bone repair.

Bias-Independent Inter-Modulation Method for Simultaneously Measuring Low-Frequency Modulation and Bias Half-Wave Voltages of Mach-Zehnder Modulators

A bias-independent inter-modulation method is proposed and demonstrated for measuring low-frequency modulation and bias half-wave voltages of Mach-Zehnder modulators(MZMs).The method consists of simultaneous sinusoidal modulation on the modulation and bias ports of the MZM under test.Sinusoidal-modulated sidebands heterodyne with each other and generate the desired inter-modulation products after photodetection,which allows extracting both the modulation depth and half-wave voltage for the modulation and bias ports of the MZM.Our method is independent of bias voltages of the MZM,which can be canceled out by carefully choosing the sinusoidal-modulation frequencies.Moreover,the proposed method enables the low swing voltage for measuring both the modulation depth and half-wave voltage of MZMs.Experiments indicate that the proposed method features the simple setup and high accuracy for low-frequency response measurement ranging from 1 Hz to 1 MHz.

Direct interaction between CD155 and CD96 promotes immunosuppression in lung adenocarcinoma

Despite the advance in targeted therapy,lung adenocarcinoma(LUAD)remains one of the leading causes of death in patients with cancer.CD155,a member of poliovirus receptor–related(PRR)family,has been identified as the ligand of the Ig-like receptors tactile(CD96)and DNAM-1(CD226)on T cells.The interaction of CD155 with CD96 transmits an inhibitory signal and suppresses immune response.The interaction of CD155 with CD226 enhances the immune response.1,2,3 CD155 expression has been shown to be elevated in many types of cancers4,5 and is involved with immune suppression in melanoma.6 However,how CD155/CD96 is involved in immune response in the tumor microenvironment of LUAD remains unknown.

Who Plays the Key Role among Shanghai,Shenzhen and Hong Kong Stock Markets?

In this paper we examine the daily frequency stock market indices of Shanghai, Shenzhen and Hong Kong from January 2000 to June 2012, and use the Morlet wavelet coherence model to determine who is playing the most important role in the financial markets of China. We find that there are significant comovements between these stock markets in the medium and long run. This provides investors with opportunities to increase their capital gains. The Hong Kong stock market plays a leading role in the long run, but its leader position is threatened by fast-growing Chinese mainland stock markets, especially the Shanghai Stock Exchange. Based on our analysis, the following suggestions apply to the Chinese stock markets： establish and improve international and regional finance centers in Chinese mainland; encourage more qualified institutional investors; reposition the market relations among Hong Kong, Shanghai and Shenzhen; and increase deregulation and internationalization to speed up the integration of financial resources.