负载纳米钽的液晶显示光固化聚乳酸支架制备及促成骨性能

背景:聚乳酸因具有良好的生物相容性和可控的降解速率在生物医学工程中得到了广泛应用,然而存在机械强度低和生物活性不足等缺陷,限制了其在骨组织工程中的进一步应用。目的:构建聚乳酸/聚多巴胺/钽(PLA/PDA/Ta)骨组织工程支架,探究其生物安全性和体外促成骨性能。方法:利用液晶显示光固化技术制备具有多孔结构的聚乳酸(PLA)支架,将PLA支架分别浸泡在多巴胺溶液与多巴胺-纳米钽混合溶液中分别制备聚乳酸/聚多巴胺(PLA/PDA)支架、PLA/PDA/Ta支架,表征支架的微观形貌与水接触角。将MC3T3-E1细胞分别与PLA、PLA/PDA、PLA/PDA/Ta支架共培养,进行CCK-8检测与活/死细胞染色;成骨诱导分化后,进行碱性磷酸酶、茜素红染色及成骨基因检测。结果与结论:①扫描电镜下可见3种支架均具有互连的多孔三维结构,平均孔径为200μm;PLA/PDA/Ta支架的水接触角低于PLA、PLA/PDA支架(P<0.05);②CCK-8检测显示,相较于PLA、PLA/PDA支架,PLA/PDA/Ta支架可促进细胞的增殖(P<0.05);活/死细胞染色显示3组细胞增殖良好;③碱性磷酸酶与茜素红染色显示,相较于PLA、PLA/PDA支架,PLA/PDA/Ta支架可促进细胞碱性磷酸酶的表达与矿化结节形成;RT-qPCR检测显示,相较于PLA、PLA/PDA支架,PLA/PDA/Ta支架可促进细胞骨形态发生蛋白、Runx-2及Ⅰ型胶原mRNA的表达(P<0.05,P<0.01);④结果表明,PLA/PDA/Ta支架具有优异的促细胞增殖与成骨活性。

Smart Cellulose‑Based Janus Fabrics with Switchable Liquid Transportation for Personal Moisture and Thermal Management

The Janus fabrics designed for personal moisture/thermal regulation have garnered significant attention for their potential to enhance human comfort.However,the development of smart and dynamic fabrics capable of managing personal moisture/thermal comfort in response to changing external environments remains a challenge.Herein,a smart cellulose-based Janus fabric was designed to dynamically manage personal moisture/heat.The cotton fabric was grafted with N-isopropylacrylamide to construct a temperature-stimulated transport channel.Subsequently,hydrophobic ethyl cellulose and hydrophilic cellulose nanofiber were sprayed on the bottom and top sides of the fabric to obtain wettability gradient.The fabric exhibits anti-gravity directional liquid transportation from hydrophobic side to hydrophilic side,and can dynamically and continuously control the transportation time in a wide range of 3–66 s as the temperature increases from 10 to 40℃.This smart fabric can quickly dissipate heat at high temperatures,while at low temperatures,it can slow down the heat dissipation rate and prevent the human from becoming too cold.In addition,the fabric has UV shielding and photodynamic antibacterial properties through depositing graphitic carbon nitride nanosheets on the hydrophilic side.This smart fabric offers an innovative approach to maximizing personal comfort in environments with significant temperature variations.

Molecular simulation study of the microstructures and properties of pyridinium ionic liquid[HPy][BF_(4)]mixed with acetonitrile

The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.

Perfluoropentane-based oxygen-loaded nanodroplets reduce microglial activation through metabolic reprogramming

Microglia,the primary immune cells within the brain,have gained recognition as a promising therapeutic target for managing neurodegenerative diseases within the central nervous system,including Parkinson’s disease.Nanoscale perfluorocarbon droplets have been reported to not only possess a high oxygen-carrying capacity,but also exhibit remarkable anti-inflammatory properties.However,the role of perfluoropentane in microglia-mediated central inflammatory reactions remains poorly understood.In this study,we developed perfluoropentane-based oxygen-loaded nanodroplets(PFP-OLNDs)and found that pretreatment with these droplets suppressed the lipopolysaccharide-induced activation of M1-type microglia in vitro and in vivo,and suppressed microglial activation in a mouse model of Parkinson’s disease.Microglial suppression led to a reduction in the inflammatory response,oxidative stress,and cell migration capacity in vitro.Consequently,the neurotoxic effects were mitigated,which alleviated neuronal degeneration.Additionally,ultrahigh-performance liquid chromatography–tandem mass spectrometry showed that the anti-inflammatory effects of PFP-OLNDs mainly resulted from the modulation of microglial metabolic reprogramming.We further showed that PFP-OLNDs regulated microglial metabolic reprogramming through the AKT-mTOR-HIF-1αpathway.Collectively,our findings suggest that the novel PFP-OLNDs constructed in this study alleviate microglia-mediated central inflammatory reactions through metabolic reprogramming.

发育性髋关节发育不良患者固液双相纤维增强软骨的力学性能

背景:发育性髋关节发育不良由于髋臼、股骨头存在结构、大小及方向等方面的畸形,患者长时间活动或站立会引起腹股沟疼痛,如果得不到有效的治疗,患者的正常活动将严重受限。目的:基于FEBio建立具有固液双相纤维增强软骨的球-窝髋关节有限元模型,探究发育性髋关节发育不良患者和正常人髋关节软骨的生物力学特性。方法:对1名发育性髋关节发育不良患者和1名正常志愿者进行髋关节建模,模型包含左盆骨、左股骨及附着其上的软骨。验证正常髋关节固液双相纤维增强软骨模型有效性后,建立髋关节发育不良患者髋关节有限元模型,对比两者在单腿站立时(2 130 N静态载荷)软骨的接触应力、流体压力、固相等效应力和流体支撑率的差异。结果与结论:(1)与正常髋关节相比,载荷加载完成后1 s(承载初期),发育性髋关节发育不良患者髋臼软骨出现明显的边缘接触,且峰值接触应力(3.86 MPa)和峰值流体压力(3.76 MPa)均大于正常髋关节软骨;(2)1 500 s(承载稳定)后,2个模型软骨峰值接触应力和峰值流体压力均减小,但发育性髋关节发育不良患者软骨接触位置由软骨边缘向中心移动,流体支撑率由97.41%下降到91.08%,正常髋关节软骨流体支撑率下降了0.58%,由95.24%下降到94.66%;(3)提示单腿站立生理载荷下,发育性髋关节发育不良患者软骨出现明显的边缘载荷,其峰值接触应力、流体压力和流体支撑率的下降幅度均大于正常软骨,考虑软骨的固液双相纤维增强特性对于评估髋关节发育不良患者髋关节软骨的生物力学性能、理解髋关节发育不良病理生理机制和制定术前计划具有重要的临床意义。

双针-板结构脉冲气泡放电等离子体固氮研究

大气压低温等离子体可以利用空气直接进行氧化固氮,具有反应条件温和、参数灵活可控、避免温室气体排放等优点.本文利用双针-板电极在水中形成气泡放电等离子体,以空气为放电气体进行了固氮研究,分析了产物浓度和固氮能耗的影响因素.研究结果表明,等离子体中含有丰富的氮原子、氧原子、氢原子、激发态氮分子等活性物种,可高效合成硝态含氮产物.研究发现,脉冲参数、电极间隙、工作气体组分对气泡放电等离子体的固氮性能有重要影响.装置最高NO~-_x合成速率为19.2μmol/min,最小能耗约为11 MJ/mol.此外还发现,电极间隙为6 mm时,固氮性能最优;空气中增加适量氧气(氧气/氮气比例为0.4)可以增强产物合成,降低能耗.

Excess Liquidity Control Requires a Multi-Pronged Approach

As China opens wider to the outside world, excess liquidity has become an outstanding issue in economic operations. This paper holds that China's liquidity is relatively excessive at the present time, and such excess liquidity is a reflection of domestic and foreign economic contradictions on the monetary level. Excess liquidity will pose a potential hazard to macroeconomic operation, and a multi-pronged approach should be taken to curb and control its sources at home and abroad.

OPTIMAL PORTFOLIO ON TRACKING THE EXPECTED WEALTH PROCESS WITH LIQUIDITY CONSTRAINTS

In this article, the authors consider the optimal portfolio on tracking the expected wealth process with liquidity constraints. The constrained optimal portfolio is first formulated as minimizing the cumulate variance between the wealth process and the expected wealth process. Then, the dynamic programming methodology is applied to reduce the whole problem to solving the Hamilton-Jacobi--Bellman equation coupled with the liquidity constraint, and the method of Lagrange multiplier is applied to handle the constraint. Finally, a numerical method is proposed to solve the constrained HJB equation and the constrained optimal strategy. Especially, the explicit solution to this optimal problem is derived when there is no liquidity constraint.

Liquidity connectedness in cryptocurrency market

We examine the dynamics of liquidity connectedness in the cryptocurrency market.We use the connectedness models of Diebold and Yilmaz(Int J Forecast 28(1):57–66,2012)and Baruník and Křehlík(J Financ Econom 16(2):271–296,2018)on a sample of six major cryptocurrencies,namely,Bitcoin(BTC),Litecoin(LTC),Ethereum(ETH),Ripple(XRP),Monero(XMR),and Dash.Our static analysis reveals a moderate liquidity connectedness among our sample cryptocurrencies,whereas BTC and LTC play a significant role in connectedness magnitude.A distinct liquidity cluster is observed for BTC,LTC,and XRP,and ETH,XMR,and Dash also form another distinct liquidity cluster.The frequency domain analysis reveals that liquidity connectedness is more pronounced in the short-run time horizon than the medium-and long-run time horizons.In the short run,BTC,LTC,and XRP are the leading contributor to liquidity shocks,whereas,in the long run,ETH assumes this role.Compared with the medium term,a tight liquidity clustering is found in the short and long terms.The time-varying analysis indicates that liquidity connectedness in the cryptocurrency market increases over time,pointing to the possible effect of rising demand and higher acceptability for this unique asset.Furthermore,more pronounced liquidity connectedness patterns are observed over the short and long run,reinforcing that liquidity connectedness in the cryptocurrency market is a phenomenon dependent on the time–frequency connectedness.

After-market liquidity and IPOs underpricing： Evidence from Shari＇ah and non Shari＇ah-based firms

The underpricing of initial public offerings （IPOs） is generally explained with asymmetric information and risk. We complement these traditional explanations with a new theory proposed by Ellul and Pagano （2006） where investors worry also about the after-market illiquidity that may result from asymmetric information after the IPO. The less liquid the after-market is expected to be, the larger will be the IPO underpricing. The samples are the 41 IPOs carried out between 2001-2005. The samples are 7 Shari＇ah-based firms and 34 non Shariah-based firms. Shariah-based firms are those included in Jakarta Islamic Index （JII）, at least one period （one semester）. Regression results show that the relationship between after-market liquidity and underpricing is insignificant unless we use trading frequency as proxy for liquidity for non Shariah-based firms.

High Foreign Exchange Reserves Fuel Excess Liquidity

This article views China's excess liquidity problem in the global context. It suggests that market mechanisms, cooperation between all parties involved, and liquidity diversion, be resorted to in order to tackle the problem of excessive liquidity. This article also points out that the top priority is to solve the major problems, such as the current account surplus, the sources of excessive liquidity, the shortage of capital in rural areas, and the cause of capital distribution imbalance.

Changes of the Level of Liquidity in Time of the Financial Crisis： A Case of Polish Companies

The financial crisis undoubtedly exerted a pressure on the companies operating in Poland. Thus, it is important to undertake researches that reveal the paths and strength of the transmission of financial crisis with regard to the business entities. This paper presents partial results of the researches dedicated to the analysis of the impact of financial crisis on the financial situation of companies operating in Silesian Region in Poland. It analyses and discusses the general changes in the financial ratios that inform about the company＇s financial liquidity and the level of liquidity risk. As a research paper, it aims at justifying hypotheses about the changes of liquidity and liquidity risk in companies operating in Poland, Silesian Region within the period of 2006-2009. The tested hypotheses generally indicate the decrease of liquidity in the aftermath of crisis and a worse situation in the Silesian Region, as compared to the national level. The study is based on an application of a part of authors＇ self-developed method--the CFS Watch （Corporate Financial Situation Watch）, which consists of five analytical modules. In this study, one module is applied： the FLA Module （Financial Liquidity Analysis） with regard to financial liquidity and the level of liquidity risk. The research is based on the data collected by the Polish Central Statistical Office. The analysis of FLA Module is based on two samples of companies： companies operating in the Silesian Region （denoted as the MEPP sample）, and companies operating in Poland （denoted as the MAPP sample）. This allows developing a comparative analysis between regional and national dimension. The results of the study represent an interesting starting point for further comparative researches based on the analysis of the changes in the level of liquidity and liquidity risk of companies operating in different countries. It may form a base for finding similarities or differences in their financial situation in the aftermath of the financial crisis. The CFS Watch method in terms of the liquidity can be widely applied to make the results comparable.

Mutual Fund＇s Behavior on Stock Liquidity： Empirical Results from Chinese Security Market

This paper studies the relationship between fund investment and market liquidity by using Chinese security market data. The results show that, among several measures of market liquidity, the indexes based on volume, such as turnover and market depth, have a deeper impact on fund investment decision. Furthermore, the relationship between security liquidity and fund investment varies when market status is taken into account. On the other hand, fund investments have a negative effect on security liquidity measured by market width, while have a positive effect on other liquidity measures. The authors attribute the results to herding behavior of fund investment.

Industry-and liquidity-based momentum in Australian equities

This study examined momentum profitability in Australia,providing further evidence for intermediate-term momentum profitability.Using data spanning different market states,we found that momentum was stronger after the global financial crisis.We also examined industry-level momentum strategies and found strong evidence for industry momentum.Specifically,industries that perform well relative to other industries continue to outperform others while those that underperform continue to perform poorly.This finding suggests the exploitability of return continuation and profit-making opportunities for traders at the industry level.Regarding liquidity,we found that it has no clear predictive power for momentum returns.Hence,our results do not appear to support the conjecture that liquidity can be a determining factor for momentum profitability in Australia.

Hong Kong-Inflation and Liquidity

Property-Keep stepping on the brakes The Hong Kong Monetary Authority (HKMA) on 10 June announced new measures to tackle housing-price in- flation. The intention this time, as in previous rounds, is to limit leverage. The government also said it would introduce more land supply in Q3-2011, which would create about 6,000 new residential units. In 2010, 13,405 residential units were completed. The HKMA’s latest measures came as leverage

“Blessing or Curse”?Introduction of Bond Notes as an Antidote to Zimbabwe’s Liquidity Crises

The Zimbabwean financial sector has been retrogressive,constrained,and unpredictable since the year 2000,serving for the multiple currency periods(2009-2013)after the demonetization of the domestic dollar.The sector since then has seen a number of commercial banks fail to meet RBZ(Reserve Bank of Zimbabwe)minimum capital requirements,put under curatorship,delisted or liquidated because of a myriad of operational and financial challenges.The objective of this study is to make an assessment of whether or not the introduction of bond notes has been a curse or blessing.The study drew raw data from bank account holders,academics,general public,corporate world and commercial banks in Masvingo for analysis and interpretation.The study established that the majority of people,corporate world and commercial banks were sceptical to embrace the surrogate bond notes because of the uncertainties,operational and financial risks that they paused on the domestic financial markets.It was also discovered that most banks were quick to pay clients’withdrawals in bond notes,deduct US dollar equivalences from their accounts,and distinguish bond notes from US dollars at the point of making deposits and foreign business transactions.It was also realized that there was market indiscipline and trading in bigger US dollar notes in the informal sector and serious shortage of the same notes in the formal sector.The study concluded that the introduction of bond notes to trade parallel to the US dollar brought a serious shortage of cash on formal markets and increases in the general price level of goods and services.The study therefore recommends that the RBZ should completely withdraw the bond notes from the market to accord the US dollar its world market value and restore confidence and discipline in the Zimbabwean financial sector.The study also recommends another option of the adoption of the South African Rand as an interventionist way of solving Zimbabwe’s liquidity crises.

Stock Liquidity Risk Pricing Model Driven by Systematic and Unsystematic Risk

In the stock pricing, liquidity risk has become one of the important factors that affect the stock realizable value. Systematic and unsystematic risk decided a stock＇s liquidity risk. The author uses the stock price index growth rate and net outer disk ratio to describe a systematic and unsystematic risk faced by investors. With the help of correlation and regression analysis in SPSS software, the paper tries to establish the systematic and unsystematic risk-driven stock liquidity risk pricing model. Empirical study shows that systematic and unsystematic risk has significant influence on stock liquidity risk. The bigger circulation stock, the greater the systemic risk influence; the less the circulation stock, the larger the non-system risk influence. Calendar factor on stock returns ratio has no significant effect. Trading volume on the stock returns ratio of small companies had no significant effect. The model has important reference value for the measure of stock liquidity risk value loss.

Liquidity risk integration in portfolio choice： The bid efficient frontier

In this paper, a tractable solution is proposed to integrate, to a certain extent, market liquidity risk in the portfolio selection process. It is shown how an investor may take advantage of this additional risk source within the standard mean-variance optimization framework, by in certain circumstances overcoming the pitfalls of illiquidity and in others seizing a liquidity premium. Bid prices appear effective to capture liquidity risk. The efficient frontier conceived with bid prices consists of mean-variance optimal allocations that cover more liquid stocks （large caps） under stressed market conditions and less liquid stocks （small caps） under normal conditions.

Structural Monetary Policy, Bank Credit and Bank Liquidity—An Empirical Analysis Based on VAR Model

After the outbreak of the international financial crisis,the People’s Bank of China,based on traditional monetary policy tools,launched a series of structural monetary policy tools such as standing lending facility(SLF),medium-term lending facility(MLF),and pledged supplementary lending(PSL)and targeted at liquidity via the commercial banking system.In order to test the credit transmission effect of structured monetary policy,this paper empirically analyzes the relationship between structured monetary policy,bank liquidity and bank credit based on the VAR model.The research shows that the implementation of structured monetary policy reduces the liquidity of commercial banks in the short term and increases in loans to small or micro enterprises and agriculture-related loans,these policies have produced significant short-term effects on credit transmission in steady of long-term effects.Thus,a series of supporting measures are needed to fully exert the effects of structural monetary policy.

Resource Integration,Risk Management and Liquidity Management Strategies

The financial impact caused by the pandemic has swept the world.So far,although China has made great achievements in fighting against the pandemic,production and living order has been restored,but enterprises have faced problems in operation and management after more than half a year.For example,low resource utilization rate,weak integration ability,insufficient risk awareness,blind expansion in disadvantaged situation,high risk of financial leverage,long enterprise business and so on.The following article will conduct research on resource integration,risk management and liquidity management,and provide suggestions for enterprises to survive the economic impact of the pandemic smoothly.