Stabilizing perovskite precursors with the reductive natural amino acid for printable mesoscopic perovskite solar cells

Solution processability significantly advances the development of highly-efficient perovskite solar cells.However,the precursor solution tends to undergo irreversible degradation reactions,impairing the device performance and reproducibility.Here,we utilize a reductive natural amino acid,Nacetylcysteine(NALC),to stabilize the precursor solution for printable carbon-based hole-conductorfree mesoscopic perovskite solar cells.We find that I_(2) can be generated in the aged solution containing methylammonium iodide(MI) in an inert atmosphere and speed up the MA-FA^(+)(formamidinium) reaction which produces large-size cations and hinders the formation of perovskite phase.NALC effectively stabilizes the precursor via its sulfhydryl group which reduces I_(2) back to I^(-)and provides H^(+).The NALC-stabilized precursor which is aged for 1440 h leads to devices with a power conversion efficiency equivalent to 98% of that for devices prepared with the fresh precursor.Furthermore,NALC improves the device power conversion efficiency from 16.16% to 18.41% along with enhanced stability under atmospheric conditions by modifying grain boundaries in perovskite films and reducing associated defects.

Tailored multifunctional hydrazine derivatives for efficient printable hole-conductive-free mesoscopic perovskite solar cells via enhancing defect passivation

The low-cost and easy large-scale fabrication advantages of printable mesoscopic perovskite solar cells(p-MPSCs)are overshadowed by their limited photovoltaic conversion efficiency(PCE).Here,we introduce the hydrazide derivative of 4-Hydroxybenzoylhydrazine(4-HBH)to improve the PCE of p-MPSCs by inducing enhanced defect passivation.Both carbonyl and hydrazine groups in hydrazide groups present strong interaction with perovskite.The hydroxyl group,as an electron donor group,increases the electron cloud density of the hydrazide group in 4-HBH under the conjugation of the benzene ring,and thus enhances its interaction with perovskite.Additionally,the hydroxy group itself interacts with perovskite and passivates defects synergistically.The hydrazine agents can also reduce I2and suppress the loss of iodine in perovskite films,which inhibits the formation of iodine-related defects.Consequently,p-MPSCs with 4-HBH achieve a high PCE of 19.21%,and present well improved stability.

Management of traumatic peripheral artery pseudoaneurysm:A 10-year experience at a single center

Purpose: This study aimed to report our 10-year experience with the management of iatrogenic(penetrating trauma) and traumatic(blunt or penetrating trauma) peripheral artery pseudoaneurysms, based on data from a tertiary referral center.Methods: From January 2012 to December 2021, the medical records of consecutive patients with iatrogenic and traumatic peripheral artery pseudoaneurysms were retrospectively reviewed. Patient demographics, clinical features, imaging data, treatment details, and follow-up results were analyzed.Results: Sixty-one consecutive patients were included in this study;48(79%) were men and 13(21%) women,with a mean age of 49.4 ± 13.4 years(range 24–73 years). There were 42 patients(69%) who underwent open surgery, 18(29%) undergoing endovascular embolization or stent implantation, and one(2%) undergoing ultrasound-guided thrombin injection. All patients successfully underwent open or interventional treatment. The median follow-up was 46.8 months(2.5–117.9 months), and the overall reintervention rate was 10%. Of these,one(5%) patient in the interventional treatment group and five(12%) patients in the open surgery group underwent reintervention. The overall complication rate was 8%, with complications occurring only in the open surgery group. No deaths occurred in the peri-operative period. No late complications, such as thrombosis or pseudoaneurysm recurrence, were observed.Conclusion: Peripheral artery pseudoaneurysms arising from iatrogenic or traumatic causes can be effectively treated by both open surgery and interventional procedures in selected patients with acceptable mid-and long-term outcomes.

Changes in compressed neurons from dogs with acute and severe cauda equina constrictions following intrathecal injection of brain-derived neurotrophic factor-conjugated polymer nanoparticles

This study established a dog model of acute multiple cauda equina constriction by experimental constriction injury （48 hours） of the lumbosacral central processes in dorsal root ganglia neurons. The repair effect of intrathecal injection of brain-derived neurotrophic factor with 15 mg encapsulated biodegradable poly（lactide-co-glycolide） nanoparticles on this injury was then analyzed. Dorsal root ganglion cells （LT） of all experimental dogs were analyzed using hematoxylin-eosin staining and immunohistochemistry at 1,2 and 4 weeks following model induction. Intrathecal injection of brain-derived neurotrophic factor can relieve degeneration and inflammation, and elevate the expression of brain-derived neurotrophic factor in sensory neurons of compressed dorsal root ganglion Simultaneously, intrathecal injection of brain-derived neurotrophic factor obviously improved neurological function in the dog model of acute multiple cauda equina constriction. Results verified that sustained intraspinal delivery of brain-derived neurotrophic factor encapsulated in biodegradable nanoparticles promoted the repair of histomorphology and function of neurons within the dorsal root ganglia in dogs with acute and severe cauda equina syndrome.

Weakly Singular Symmetric Galerkin Boundary Element Method for Fracture Analysis of Three-Dimensional Structures Considering Rotational Inertia and Gravitational Forces

The Symmetric Galerkin Boundary Element Method is advantageous for the linear elastic fracture and crackgrowth analysis of solid structures,because only boundary and crack-surface elements are needed.However,for engineering structures subjected to body forces such as rotational inertia and gravitational loads,additional domain integral terms in the Galerkin boundary integral equation will necessitate meshing of the interior of the domain.In this study,weakly-singular SGBEM for fracture analysis of three-dimensional structures considering rotational inertia and gravitational forces are developed.By using divergence theorem or alternatively the radial integration method,the domain integral terms caused by body forces are transformed into boundary integrals.And due to the weak singularity of the formulated boundary integral equations,a simple Gauss-Legendre quadrature with a few integral points is sufficient for numerically evaluating the SGBEM equations.Some numerical examples are presented to verify this approach and results are compared with benchmark solutions.

A three-dimensional crosslinked chitosan sulfate network binder for high-performance Li-S batteries

Poor cycling performance caused by the shuttle effect of polysulfides is the main obstacle in the development of advanced lithium-sulfur(Li-S)batteries.Functional polymer binders with polar groups can effectively adsorb polysulfides chemically,thereby suppressing the shuttle effect.Herein,a robust three-dimensional crosslinked polymer network,which demonstrates excellent mechanical property and strong affinity for polysulfides,is prepared by the aldimine condensation and coordination reactions.The crosslinked chitosan sulfate network(CCSN)significantly enhances the cycling performance and rate capability of the sulfur cathode.The CCSN-based sulfur cathode exhibits a high initial discharge capacity of 824 m Ah g^(-1) with only 0.082%average capacity loss per cycle at 1 C.At a high rate of 4 C,the cathode exhibits a high capacity retention of 84.8%after 300 cycles.Moreover,the CCSN-based sulfur cathode exhibits an excellent cycling performance at a high sulfur loading of 2.5 mg cm^(-2),which indicates the excellent mechanical strength and binding performance of the CCSN binder for high-energy density Li-S batteries.This study demonstrates a viable approach for developing high-performance Li-S batteries for practical application.

Dynamic changes in liver function after transjugular intrahepatic portosystemic shunt in patients with cirrhosis

Purpose:To evaluate the dynamic changes in liver function after transjugular intrahepatic portosystemic shunt(TIPS)creation in patients with cirrhosis and to explore its association with clinical outcomes.Methods:This retrospective study included patients who underwent TIPS between August 2016 and December2020.Liver function was primarily evaluated using the model for end-stage liver disease(MELD)score,which was analyzed at baseline,1 week,1 month,3 months,6 months,and 12 months using one-way repeated measures ANOVA.The Kaplan-Meier method,log-rank test,and multivariate analysis were used as appropriate.Results:In total,235 patients were included in this study.The MELD score was significantly higher at 1 week(11.8±3.1 vs 13.5±3.5,p<0.05)and 1 month(11.8±3.1 vs 13.2±4.6,p<0.05)than the baseline level and recovered at 3 months(11.8±3.1 vs 11.9±3.9,p>0.05).At 12 months,the MELD score was higher than the baseline level(11.8±3.1 vs 12.4±3.2,p<0.05).Patients with a recovery of the MELD score(n=151)at 3 months had a lower probability of overt and severe HE(log-rank p=0.015 and p=0.027,respectively)than those without recovery(n=84).Logistic regression analysis revealed that albumin(odds ratio[OR],0.926;95%confidence interval[CI],0.863–0.992;p=0.029)and platelet count(OR,0.993;95%CI,0.987–0.999;p=0.033)were independent predictive factors for non-recovery of the MELD score at 3 months.Conclusions:Liver function after TIPS creation showed a trend of deterioration at first,followed by recovery.Recovery of liver function at three months was associated with reduced overt and severe HE.

TAXOL INDUCES CELL DEATH WITH CYTOPLASM VACUOLIZATION IN PARAPTOSIS-LIKE BUT NOT ONCOSIS FASHION IN ASTC-a-1 CELLS

Recently,we found that high concentration of taxol(70μM)induced cell death with cytoplasm vacuolization,the typical characteristic of both paraptosis and oncosis,in human lung carcinoma(ASTC-a-1)cells.This report was designed to further deternine the form of taxo-induced cell death with cytoplasm vacuolization.It is generally coneidered that the cytoplasm vacuolization in oncosis due to the sweling of endoplasmic reticulum(ER),mitochondria,lysosomes and muclei occurs after the loss of mitochondrial mermbrane potential(△ψm).However,flow cytometry(FCM)analysis showed that taxol induced cy toplsm vacuolization preceded the loss of(△ψm).Moreover,taxol treatment did not induce the collapse of microtubule,the ty pical characteristic of oncosis.These data demonstrated that taxol-induced cell death with cytoplasm vacuolization is not onoosis.FCM analysis by Annexin V-FTTC/PI apoptosis detection kit further demoustrated that taxol-induced cell death with cytoplasm vacuolization is not apoptosis.In conclusion,in combination with our recent in ritro and in vito data,this report further demonstrates that high concentration of taxol induces cell death with cytoplasm vacuolization in paraptosis like but not oncosis fashion.

Natural Cocoons Enabling Flexible and Stable Fabric Lithium–Sulfur Full Batteries

Lithium–sulfur batteries are highly appealing as highenergy power systems and hold great application prospects for flexible and wearable electronics.However,the easy formation of lithium dendrites,shuttle effect of dissolved polysulfides,random deposition of insulating lithium sulfides,and poor mechanical flexibility of both electrodes seriously restrict the utilization of lithium and stabilities of lithium and sulfur for practical applications.Herein,we present a cooperative strategy employing silk fibroin/sericin to stabilize flexible lithium–sulfur full batteries by simultaneously inhibiting lithium dendrites,adsorbing liquid polysulfides,and anchoring solid lithium sulfides.Benefiting from the abundant nitrogen-and oxygen-containing functional groups,the carbonized fibroin fabric serves as a lithiophilic fabric host for stabilizing the lithium anode,while the carbonized fibroin fabric and the extracted sericin are used as sulfiphilic hosts and adhesive binders,respectively,for stabilizing the sulfur cathode.Consequently,the assembled Li–S full battery provided a high areal capacity(5.6 mAh cm−2),limited lithium excess(90%),a high volumetric energy density(457.2 Wh L^(−1)),high-capacity retention(99.8%per cycle),and remarkable bending capability(6000 flexing cycles at a small radius of 5 mm).

数字化口内扫描技术在牙体预备实践教学中的应用

目的:探索数字化技术在口腔修复学住院医师规范化培训中的应用及推广。方法:本实验以45名参与浙江大学医学院附属口腔医院口腔住院医师规范化培训的住培生为研究对象,分为对照组和实验组。对照组采用传统教师理论授课和操作示教,实验组采用数字化口内扫描技术引导下金属烤瓷全冠牙体预备教学。通过体位姿势、边缘形态、点线角、聚合度、预备量5个方面对牙体预备质量进行评分考核。结果:全冠牙体预备考核成绩实验组(92.26±2.97)与对照组(89.91±4.20)之间存在统计学差异(P<0.05)。结论:数字化引导的金属烤瓷全冠牙体预备的教学可以有效提高学生的学习主动性、理论知识的掌握和应用、临床思考和实践能力,为最终培养出具有优异临床岗位胜任力的口腔住院医师提供基础。

Alkali and alkaline ions co-substitution of P2 sodium layered oxides for sodium ion batteries

Alkali and alkaline ion substitutions enhance the electrochemical properties of P2 sodium layered oxide,while the effect on electrochemical property enhancement of alkali and alkaline ions co-substitution is still unclear.In this work,the structural and electrochemical properties of the Li alkali and Mg alkaline ions co-substituted P2 layered oxide Na_(0.67)(Li_(0.5)Mg_(0.5))_(0.1)(Ni_(0.33)Mn_(0.67))_(0.9)O_(2)are investigated in detail.Compared to the pristine and single-ion substituted materials,the co-substituted material shows an enhanced cycling performance with a reversible ca-pacity of 127 mAh/g and a capacity retention of 75%over 100 cycles at 0.5C.Galvanostatic intermittent titration technique(GITT)and cyclic voltammetry(CV)results show that the Li and Mg synergistically improve the ion diffusion.Moreover,the structure stability is also improved by the Li and Mg co-substitution that is clarified by operando X-ray diffraction(XRD)measurements.These results explain the origin of the enhanced electrochemical properties of the Li/Mg co-substituted P2 layered oxides for sodium ion batteries.

Exploring porous zeolitic imidazolate frame work-8(ZIF-8)as an efficient filler for high-performance poly(ethyleneoxide)-based solid polymer electrolytes

Nano Research volume 13,pages2259–2267(2020)Cite this article 277 Accesses 1 Altmetric Metrics details Abstract The incorporation of inorganic fillers into poly(ethyleneoxide)(PEO)-based solid polymer electrolytes(SPEs)is well known as a low-cost and effective method to improve their mechanical and electrochemical properties.Porous zeolitic imidazolate framework-8(ZIF-8)is firstly used as the filler for PEO-based SPEs in this work.Due to the introduction of ZIF-8,an ionic conductivity of 2.2×10^−5 S/cm(30℃)is achieved for the composite SPE,which is one order of magnitude higher than that of the pure PEO.ZIF-8 also accounts for the broader electrochemical stability window and lithium ion transference number(0.36 at 60℃)of the composite SPE.Moreover,the improved mechanism of ZIF-8 to the composite SPE is investigated by zeta potential and Fourier transform infrared spectrograph characterizations.The stability at the composite SPE/lithium interface is greatly enhanced.The LiFePO4||Li cells using the composite SPE exhibit high capacity and excellent cycling performance at 60℃,i.e.,85%capacity retention with 111 mA·h/g capacity retained after 350 cycles at 0.5 C.In comparison,the cells using the pure PEO show fast capacity decay to 74 mA·h/g maintaining only 68 capacity.These results indicate that the PEO-based SPEs with ZIF-8 are of great promise for the application in solid-state lithium metal batteries.

A novel porous silica-zirconia coating for improving bond performance of dental zirconia

Objective:To coat a zirconia surface with silica-zirconia using a dip-coating technique and evaluate its effect on resin-zirconia shear bond strength(SBS).Methods:A silica-zirconia suspension was prepared and used to coat a zirconia surface using a dip-coating technique.One hundred and eighty-nine zirconia disks were divided into three groups according to their different surface treatments(polishing,sandblasting,and silica-zirconia coating).Scanning electron microscopy(SEM),energy dispersive X-ray(EDX),and X-ray diffraction(XRD)were used to analyze the differently treated zirconia surfaces.Different primer treatments(Monobond N,Z-PRIME Plus,and no primer)were also applied to the zirconia surfaces.Subsequently,180 composite resin cylinders(Filtek Z350)were cemented onto the zirconia disks with resin cement(RelyX Ultimate).The SBS was measured after water storage for 24 h or 6 months.The data were analyzed by two-way analysis of variance(ANOVA).Results:SEM and EDX showed that the silica-zirconia coating produced a porous layer with additional Si,and XRD showed that only tetragonal zirconia was on the silica-zirconia-coating surface.Compared with the control group,the resin-zirconia SBSs of the,andblasting group and silica-zirconia-coating group were significantly increased(P<0.05).The silica-zirconia coating followed by the application of Monobond N produced the highest SBS(P<0.05).Water aging significantly reduced the resin-zirconia SBS(P<0.05).Conclusions:Dip-coating with silica-zirconia might be a feasible way to improve resin-zirconia bonding.

双相纳米结构化可实现纳米多孔金属的优异柔性与综合力学性能

纳米多孔金属的力学性能对其在柔性电子领域的应用具有重要意义.本文报道了一种高强度、高硬度、柔韧性好的纳米多孔Cu@Zr-Cu-Al金属玻璃(NP Cu@Zr-Cu-Al MG)复合材料,该材料采用两步脱合金法合成.首先,从Cu_(46)Zr_(23.5)Y_(23.5)Al_(7)合金的伪二元MG体系(Zr_(47)Cu_(46)Al_(7)MG+Y_(47)Cu_(46)Al_(7)MG)中选择性蚀刻活性富Y的MG相,制备了柔性纳米多孔Zr-Cu-Al金属玻璃(NP Zr-Cu-Al MG).进一步蚀刻得到NP Cu@Zr-Cu-Al MG,其中Cu层均匀地覆盖在MG韧带基体上.由于NP Cu@Zr-Cu-Al MG的无裂纹结构和柔性Zr-Cu-Al MG的存在,使其具有良好的柔性.NP Cu@Zr-Cu-Al MG的抗拉强度高达143.9 MPa,纳米硬度高达0.79 GPa.Zr-Cu-Al MG强化相抑制了Cu@Zr-Cu-Al韧带的断裂,有效抑制了裂纹在NP Cu@Zr-Cu-Al MG中的萌生和扩展,提高了复合材料的综合力学性能.NP Cu@Zr-Cu-Al MG可直接用作超级电容器和葡萄糖生物传感器的电极,比纯NP Zr-Cu-Al MG电极展现出更好的电导率和超电容容量.

Understanding the macroscopical flexibility/fragility of nanoporous Ag:Depending on network connectivity and micro-defects

The effective engineering applications of nanoporous metals(NPMs)in flexible energy storage and wearable healthcare biosensor monitoring require its uniform ligaments network,specifically crack-free and flexible monolithic bodies.However,the macroscopic fragility of NPMs restricts their applications in wearable electronics fields.Here we focus on the synthetization of highly flexible NPMs.The effects of structural factors,e.g.ligament-network connectivity and micro-cracks on the mechanical properties of nanoporous Ag(np Ag)are investigated.The well-interconnected np Ag metal exhibits higher tensile strength,nanohardness and Vickers hardness than those for the ill-interconnected np Ag metal.The quality of the network connectivity dominates the strength and hardness of the np Ag.The flexibility/fragility is determined by the micro-crack in np Ag.The crack-free np Ag exhibits good flexible behavior.When micro-cracks are introduced,the np Ag becomes fragile.The control of soft volume shrinkage rate(Vsr)and slow surface diffusivity(Ds)effectively suppresses the crack initiation and propagation of as-formed np Ag.These results provide useful insights to synthesize more flexible and crack-free NPM materials for effective use in public wearable electronics and diverse flexible engineering applications in the future.

Fast Numerical Simulation of Two-Phase Transport Model in the Cathode of a Polymer Electrolyte Fuel Cell

In this paper,we apply streamline-diffusion and Galerkin-least-squares fi-nite element methods for 2D steady-state two-phase model in the cathode of polymer electrolyte fuel cell(PEFC)that contains a gas channel and a gas diffusion layer(GDL).This two-phase PEFC model is typically modeled by a modified Navier-Stokes equation for the mass and momentum,with Darcy’s drag as an additional source term in momentum for flows through GDL,and a discontinuous and degenerate convectiondiffusion equation for water concentration.Based on the mixed finite element method for the modified Navier-Stokes equation and standard finite element method for water equation,we design streamline-diffusion and Galerkin-least-squares to overcome the dominant convection arising from the gas channel.Meanwhile,we employ Kirchhoff transformation to deal with the discontinuous and degenerate diffusivity in water concentration.Numerical experiments demonstrate that our finite element methods,together with these numerical techniques,are able to get accurate physical solutions with fast convergence.

Circularly polarized luminescence induced by excimer based on pyrene-modified binaphthol

A new chiral bromobinaphthol-pyrene compound was developed to achieve a green circularly polarized luminescence(CPL)from its excimer with a dissymmetry factor(|glum|)value of 4.3×10^-3 and a high quantum yieldΦF,solid up to 55.9%,while no CPL signals could be observed for the blue luminescence from unimolecule.Meanwhile,reversal CPL signals can be observed from both concentrated solution and solid.

Risks and Causes of Financial Sector’s High Growth in China

In recent years,China’s financial sector has witnessed a high growth trend.This trend has been caused by several reasons:the traditional macro-control tools do not match the new normal characteristics of China’s economy growth,the regulatory reform is lagging behind the rapid progress of financial innovation,and the drastic fluctuations of the stock market are combined with a new round of increase in real estate price.In particular,this round of high growth in the financial sector occurs in the context of a rapid decline of manufacturing sector,which reflects the low efficiency of financial operations.It also means the foundation of financial stability and sustainable development is losing and high risks are coming.To deal with this change properly,we need to further deepen financial reform and improve financial supervision,and create a favorable financial environment for the real economy.At the same time,researchers should also reflect on and study the characteristics of China’s financial development,and provide the theoretical basis for maintaining financial security.