Clinical efficacy and safety of kyphoplasty for the treatment of osteoporotic vertebral compression fractures at different surgical timings based on the theory of“dynamic-static integration”

Objective:To investigate the clinical efficacy and safety of percutaneous kyphoplasty at different surgical timings in the treatment of osteoporotic vertebral compression fracture(OVCF)based on the theory of“dynamic-static integration”.Methods:Patients with OVCF who underwent percutaneous kyphoplasty in our hospital were selected and divided into Groups A,B,and C for those undergoing surgery within 7,7—21,and>21 days of fracture occurrence.The variations in the amount of bone cement injected,pre-and post-operative pain levels,functional activity,deformity correction of the injured vertebrae,bone cement leakage,and vertebral body height loss were compared among the three groups.Results:Regarding pain relief and functional activity,the postoperative Visual Analog Scale and Oswestry Disability Index scores of the three groups significantly improved.Furthermore,the deformities of the injured vertebrae in the three groups were significantly corrected,with Groups A and B exhibiting superior correction compared to Group C.Moreover,the bone cement leakage rates in groups A and C were higher than that in Group B.At the 3-month follow-up,the loss of vertebral height in Group C was significantly higher than those in groups A and B.Conclusion:Kyphoplasty is effective for OVCF treatment.Early surgery can effectively restore the vertebral height of the injured vertebra,reduce kyphosis,and reduce height loss of the injured vertebra after surgery;nevertheless,treatment within 1—3 weeks of the fracture can reduce the occurrence of bone cement leakage,making the surgery safer.Therefore,surgical treatment within 1—3 weeks of fracture is safer and can achieve satisfactory therapeutic effects.From the perspective of traditional Chinese medicine,PKP surgery can transform the fracture end from a micromotion state to a fixed state,which fully embodies the theory of“dynamic-static integration”.

Negative pressure device-assisted autologous fat grafting: A case report

This report describes a novel technique for improving depressed scars using negative pressure suction-assisted autologous fat grafting.A 35-year-old woman presented with a 20-year history of bilateral central buttock con-cavities,causing aesthetic concerns.To maximize fat graft survival and enhance tissue volume,we implemented intermittent negative pressure suction on the recipient area for one month preoperatively.The patient expressed satisfaction with the cosmetic outcome,and a three-month follow-up confirmed a significantly improved fat graft survival rate.This minimally invasive,cost-effective,and easily reproducible technique offers a promising clinical strategy for treating depressed scars.

金属卟啉修饰的多孔聚苯胺基氧还原电催化剂

碳基非金属氧还原(ORR)电催化剂的研究近年来发展迅速,通过掺入杂原子等方法虽获得了一定的ORR活性,但仍需进一步提高。以此类电催化剂为基体,引入更多的活性位点,有可能获得更好的ORR活性。本文首先以带负电荷的SiO_(2)纳米球通过静电作用吸附带正电荷的质子化苯胺分子,再通过聚合反应实现聚苯胺(PANI)对SiO_(2)纳米球的包覆,之后将四甲氧基苯基铁卟啉(FeP)沉积在PANI表面,经高温热解,并去除SiO_(2)模板,得到了一种新型的多孔ORR电催化剂。在0.1 mol·L^(−1) KOH水溶液中,电催化剂的ORR半波电位达0.843 V(vs.可逆氢电极(RHE)),优于文献报道的大部分碳基非金属ORR电催化剂,与商业Pt/C相近。显著提高的ORR活性可能源于孔结构(平均孔径18 nm,孔容1.1 cm^(3)·g^(−1))、高比表面积(687.5 m^(2)·g^(−1))和高氮含量(6.4%)。在加速耐久性测试中,电催化剂的ORR半波电位衰减25 mV,与其它碳基非金属ORR电催化剂相当,且远优于商业Pt/C(衰减74 mV)。另外,电催化剂应用于氢氧根交换膜燃料电池(HEMFC)时的单池峰值功率密度达42 mW·cm−2。

Growth of Carbon Nanocoils by Porous α-Fe2O3/SnO2 Catalyst and Its Buckypaper for High Efficient Adsorption

High-purity(99%)carbon nanocoils(CNCs)have been synthesized by using porousα-Fe2O3/SnO2 catalyst.The yield of CNCs reaches 9,098%after a 6 h growth.This value is much higher than the previously reported data,indicating that this method is promising to synthesize high-purity CNCs on a large scale.It is considered that an appropriate proportion of Fe and Sn,proper particle size distribution,and a loose-porous aggregate structure of the catalyst are the key points to the high-purity growth of CNCs.Benefiting from the high-purity preparation,a CNC Buckypaper was successfully prepared and the electrical,mechanical,and electrochemical properties were investigated comprehensively.Furthermore,as one of the practical applications,the CNC Buckypaper was successfully utilized as an efficient adsorbent for the removal of methylene blue dye from wastewater with an adsorption efficiency of 90.9%.This study provides a facile and economical route for preparing high-purity CNCs,which is suitable for large-quantity production.Furthermore,the fabrication of macroscopic CNC Buckypaper provides promising alternative of adsorbent or other practical applications.

VAT Neutrality and Corporate Cash Holdings—Based on the Research of Uncredited VAT Refund Policy

This paper regards the uncredited value-added tax(VAT)refund policy promulgated in 2018 as an exogenous shock to improve the neutrality for VAT.Based on the statistics of listed companies in the non-financial sectors from 2013 to 2020,this paper applies the difference-in-differences(DID)approach to study the impact of the uncredited VAT refund policy on corporate cash holdings.The study finds that the policy has eased the impact of non-tax-neutral impact of non-refundable tax credits and lowered the level of corporate cash holdings.Furthermore,the analysis of capital sources verified that the policy has optimized the corporate capital conditions.These findings have proved to be robust after a series of tests.At the level of cross-sectional differences,the uncredited VAT refund policy exerts both"resource effect"and"signal effect",enabling companies to reduce cash holdings in the dimensions of both tax endowment and market expectation.At the level of policy effects,the policy improved the corporate behavior of high cash holdings for the production and operation cycle,with more notable impact on enterprises with higher tax credit rating.At the level of economic consequences,the adjustment of corporate cash holdings induced by uncredited VAT refund policy has significantly improved operating performance and reduced performance volatility,with a greater impact on enterprises with high capital intensity.The research findings evaluate the uncredited VAT refund policy from the perspective of tax neutrality,laying a theoretical foundation for further optimizing the uncredited VAT refund policy and the modern fiscal,tax and financial systems.

创业资本与企业创新:情怀何处安放?——来自中国工业企业的证据

本文将1998—2009年的中国工业企业数据库与China Venture投中集团的CVSource数据库相匹配,考察中国创业资本与企业创新的关系,进而检验甄别效应与增值效应。研究发现,与无创业资本支持的企业相比,有创业资本支持的企业具有更高的创新投入、创新产出、创新效率与更优的投资质量;与创业资本介入之前相比,企业在创业资本介入之后具有更高的创新投入,但在创新产出、创新效率和投资质量方面则没有显著差异。在控制了样本选择偏差之后,干预效应模型、倾向得分匹配与差中差估计法均表明本文结论具有稳健性。进一步的分析发现,对于获得创业资本支持的企业,其创新水平在创业资本介入之前已经显著高于无创业资本支持的企业;创业资本的介入并没有引起创新与投资质量的显著动态变化;对于创新投入、创新产出与已投资本回报率较高的企业,其引进创业资本的概率更大。这些结果表明,中国创业资本的甄别效应远大于增值效应,创新优先假设成立的可能性大于创业资本优先假设。