Strong Interaction Between Redox Mediators and Defect-Rich Carbons Enabling Simultaneously Boosted Voltage Windows and Capacitance for Aqueous Supercapacitors

Energy density,the Achilles’heel of aqueous supercapacitors,is simultaneously determined by the voltage window and specific capacitance of the carbon materials,but the strategy of synchronously boosting them has rarely been reported.Herein,we demonstrate that the rational utilization of the interaction between redox mediators(RMs)and carbon electrode materials,especially those with rich intrinsic defects,contributes to extended potential windows and more stored charges concurrently.Using 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxyl(4OH-TEMPO)and intrinsic defect-rich carbons as the RMs and electrode materials,respectively,the potential window and capacitance are increased by 67%and sixfold in a neutral electrolyte.Moreover,this strategy could also be applied to alkaline and acid electrolytes.The first-principle calculation and experimental results demonstrate that the strong interaction between 4OH-TEMPO and defectrich carbons plays a key role as preferential adsorbed RMs may largely prohibit the contact of free water molecules with the electrode materials to terminate the water splitting at elevated potentials.For the RMs offering weaker interaction with the electrode materials,the water splitting still proceeds with a thus sole increase of the stored charges.The results discovered in this work could provide an alternative solution to address the low energy density of aqueous supercapacitors.

Electrochemical Kinetic Modulators in Lithium–Sulfur Batteries:From Defect-Rich Catalysts to Single Atomic Catalysts

Lithium–sulfur batteries exhibit unparalleled merits in theoretical energy density(2600 W h kg^(-1))among next-generation storage systems.However,the sluggish electrochemical kinetics of sulfur reduction reactions,sulfide oxidation reactions in the sulfur cathode,and the lithium dendrite growth resulted from uncontrollable lithium behaviors in lithium anode have inhibited high-rate conversions and uniform deposition to achieve high performances.Thanks to the“adsorption-catalysis”synergetic effects,the reaction kinetics of sulfur reduction reactions/sulfide oxidation reactions composed of the delithiation of Li_(2)S and the interconversions of sulfur species are propelled by lowering the delithiation/diffusion energy barriers,inhibiting polysulfide shuttling.Meanwhile,the anodic plating kinetic behaviors modulated by the catalysts tend to uniformize without dendrite growth.In this review,the various active catalysts in modulating lithium behaviors are summarized,especially for the defect-rich catalysts and single atomic catalysts.The working mechanisms of these highly active catalysts revealed from theoretical simulation to in situ/operando characterizations are also highlighted.Furthermore,the opportunities of future higher performance enhancement to realize practical applications of lithium–sulfur batteries are prospected,shedding light on the future practical development.

Defect-rich N/O-co-doped porous carbon frameworks as anodes for superior potassium and sodium-ion batteries

Carbon with its high electrical conductivity,excellent chemical stability,and structure ability is the most promising an-ode material for sodium and potassium ion batteries.We developed a defect-rich porous carbon framework(DRPCF)built with N/O-co-doped mesoporous nanosheets and containing many defects using porous g-C_(3)N_(4)(PCN)and dopamine(DA)as raw materials.We prepared samples with PCN/DA mass ratios of 1/1,2/1 and 3/1 and found that the one with a mass ratio of 2/1 and a carbonization temperature of 700℃ in an Ar atmosphere(DRPCF-2/1-700),had a large specific surface area with an enormous pore volume and a large number of N/O heteroatom active defect sites.Because of this,it had the best pseudocapacitive sodium and potassium ion stor-age performance.A half battery of Na//DRPCF-2/1-700 maintained a capacity of 328.2 mAh g^(-1) after being cycled at 1 A g^(-1) for 900 cycles,and a half battery of K//DRPC-2/1-700 maintained a capacity of 321.5 mAh g^(-1) after being cycled at 1 A g^(-1) for 1200 cycles.The rate capability and cycling stability achieved by DRPCF-2/1-700 outperforms most reported carbon materials.Finally,ex-situ Raman spectroscopy analysis result confirms that the filling and removing of K^(+)and Na^(+)from the electrochemically active defects are responsible for the high capacity,superior rate and cycling performance of the DRPCF-2/1-700 sample.

Fast formation of single-unit-cell-thick and defect-rich layered double hydroxide nanosheets with highly enhanced oxygen evolution reaction for water splitting

The development of high-efficiency electrocatalysts for oxygen evolution reactions （OERs） plays an important role in the water-splitting process. Herein, we report a facile way to obtain two-dimensional （2D） single-unit-cell-thick layered double hydroxide （LDH） nanosheets （NSs, - 1.3 nm） within only 5 min. These nanosheets presented significantly enhanced OER performance compared to bulk LDH systems fabricated using the conventional co-precipitation method. The current strategy further allowed control over the chemical compositions and electrochemical activities of the LDH NSs. For example, CoFe-LDH NSs presented the lowest overpotential of 0.28 V at 10 mA/cm2, and the NiFe-LDHs NSs showed Tafel slopes of 33.4 mV/decade and nearly 100% faradaic efficiency, thus outperforming state-of-the-art IrO2 water electrolysis catalysts. Moreover, positron annihilation lifetime spectroscopy and high-resolution transmission electron microscopy observations confirmed that rich defects and distorted lattices occurred within the 2D LDH NSs, which could supply abundant electrochemically active OER sites. Periodic calculations based on density functional theory （DFT） further showed that the CoFe- and NiFe-LDHs presented very low energy gaps and obvious spin-polarization behavior, which facilitated high electron mobility during the OER process. Therefore, this work presents a combined experimental and theoretical study on 2D single-unit-cell-thick LDH NSs with high OER activities, which have potential application in water splitting for renewable energy.

Multi-node CdS hetero-nanowires grown with defect-rich oxygen-doped MoS2 ultrathin nanosheets for efficient visible-light photocatalytic H2 evolution

Developing low-cost and high-efficiency photocatalysts for hydrogen production from solar water splitting is intriguing but challenging. In this study, unique one-dimensional （1D） multi-node MoS2/CdS hetero-nanowires （NWs） for efficient visible-light photocatalytic H2 evolution are synthesized via a facile hydrothermal method. Flower-like sheaths are assembled from numerous_ defect-rich O-incorporated {0001} MoS2 facet surrounded CdS NW stems are ultrathin nanosheets （NSs）, and {1120}- grown preferentially along the c-axis. Interestingly, the defects in the MoS2 NSs provide additional active S atoms on the exposed edge sites, and the incorporation of O reduces the energy barrier for H2 evolution and increases the electric conductivity of the MoS2 NSs. Moreover, the recombination of photoinduced charge carriers is significantly inhibited by the heterojunction formed between the MoS2 NSs and CdS NWs. Therefore, in the absence of noble metals as co-catalysts, the 1D MoS2 NS/CdS NW hybrids exhibit an excellent H2-generation rate of 10.85 mmol·g^-1·h^-1 and a quantum yield of 22.0% at ,λ = 475 nm, which is far better than those of Pt/CdS NWs, pure MoS2 NSs, and CdS NWs as well as their physical mixtures. Our results contribute to the rational construction of highly reactive nanostructures for various catalytic applications.

Atomically thin defect-rich Ni-Se-S hybrid nanosheets as hydrogen evolution reaction electrocatalysts

Facile design of economic-effective hydrogen evolution reaction(HER)catalysts with non-noble materials are promising for the production of renewable chemical fuels.Two-dimensional(2D)ultrathin transition metal dichalcogenides(TMDs)materials with large specific surface area and abundant catalytic active sites can significantly enhance their catalytic activities.Herein,we design and synthesize an atomically thin Ni-Se-S based hybrid nanosheet(NiSe1.2S0.8)via a simple solvothermal method,the thickness of NiSe1.2S0.8 nanosheets is only about 1.1 nm.Benefiting from the ultrathin nanostructure and rich defects,the optimal NiSe1.2S0.8 exhibits good electrocatalytic activity with the overpotential of 144 mV at−10 mA·cm−2,a small Tafel slope of 59 mV·dec−1,and outstanding catalytic stability in acid electrolyte for HER.The theoretical results show that hybrid electrocatalyst by S incorporation possesses the optimal adsorption free energy of hydrogen(ΔGH*).This study provides a simple method to synthesize a highperformance multicomponent electrocatalysts with the ultrathin nanostructures and abundant defects.

Grow defect-rich bamboo-like carbon nanotubes on carbon black for enhanced microwave absorption properties in X band

Due to the limited electromagnetic wave(EMW)loss capacity and agglomeration,carbon black(CB)gradually fails to meet the increasingly harsh demanding conditions.Herein,defect-rich bamboo-like carbon nanotubes(CNTs)were grown on CB by the process of chemical vapor deposition.CNTs prepared in situ on CB can assist it to build a developed multilevel conductive network and introduce plentiful CB/CNTs nano-interfaces.What’s more,the defects that accompany the growth of CNTs endow CNTs with a moderate conductivity and good impedance matching,thereby causing an effective microwave absorption(MA).Meanwhile,the high-density defects on CNTs can induce dipole polarization to further strengthen the EMW loss ability.The influence of CNTs with different growth time on MA performance has been explored.Profiting from the structural merits,the synthesized CB-CNT with CNTs growth time of 40 min exhibits the optimal absorbing property,which has the minimum reflection loss of-53.6 d B and maximum effective absorption bandwidth of 4.1 GHz with the thickness of 2.7 mm,covering almost the entire X band.The introduction of defect-rich CNTs significantly enhances the EMW loss ability of CB,which provides a rational strategy for the design of high-efficient microwave absorption materials.

Defect-rich titanium nitride nanoparticle with high microwaveacoustic conversion efficiency for thermoacoustic imaging-guided deep tumor therapy

Pulse microwave excite thermoacoustic(TA)shockwave to destroy tumor cells in situ.This has promising applications for precise tumor therapy in deep tissue.Nanoparticle(NP)with high microwave-acoustic conversion is the key to enhance the efficiency of therapy.In this study,we firstly developed defect-rich titanium nitride nanoparticles(TiN NPs)for pulse microwave excited thermoacoustic(MTA)therapy.Due to a large number of local structural defects and charge carriers,TiN NPs exhibit excellent electromagnetic absorption through the dual mechanisms of dielectric loss and resistive loss.With pulsed microwave irradiation,it efficiently converts the microwave energy into shockwave via thermocavitation effect,achieving localized mechanical damage of mitochondria in the tumor cell and yielding a precise antitumor effect.In addition to the therapeutic function,the NP-mediated TA process also generates images that provide valuable information,including tumor size,shape,and location for treatment planning and monitoring.The experimental results showed that the TiN NPs could be efficiently accumulated in the tumor via intravenous infusion.With the deep tissue penetration characteristics of microwave,the proposed TiN-mediated MTA therapy effectively and precisely cures tumors in deep tissue without any detectable side effects.The results indicated that defect-rich TiN NPs are promising candidates for tumor therapy.

Confinement synthesis of bimetallic MOF-derived defect-rich nanofiber electrocatalysts for rechargeable Zn-air battery

Zn-air batteries with high energy density and safety have acquired enormous attention,while the practical application is hindered by the sluggish kinetics of the oxygen evolution reaction(OER)and the oxygen reduction reaction(ORR).In this work,a threedimensional(3D)defect-rich bifunctional electrocatalyst(CoFe/N CNFs)comprising irregular hollow CoFe nanospheres in Ndoped carbon nanofibers is presented,which is fabricated from CoFe ZIFs-derived(ZIF:zeolitic-imidazolate framework)polymer nanofibers precursor.The CoFe ZIFs with tunable particle size and composition are constructed using a confined synthesis strategy.Moreover,the Kirkendall diffusion process is available for forming the irregular hollow CoFe nanospheres,and the decomposition of polyvinylpyrrolidone(PVP)results in forming the defective carbon nanofibers,which provide more efficient active sites and enhance the electrocatalytic properties toward both OER and ORR.The optimized CoFe/N CNFs exhibit superior bifunctional activities,outperforming that of the benchmark Pt/C+RuO_(2) catalyst.As a result,the CoFe/N CNFs as an air-cathode endow the rechargeable Zn-air battery with an excellent power density of 149 mW·cm^(−2),energy density of 875 Wh·kg^(−1),and cycling stability.This work provides a new strategy to develop bifunctional electrocatalysts with desired nanostructure and regulated performance toward energy applications.

Defect-rich spinel ferrites with improved charge collection properties for efficient solar water splitting

Spinel zinc ferrite(ZnFe_(2)O_(4),ZFO)is a potential photoanode material for photoelectrochemical(PEC)water splitting because of its ideal bandgap(1.9–2.1 eV)and superior chemical stability in aqueous solutions.However,the low charge collection efficiency significantly hinders the improvement in PEC activity.Herein,we report an ultrafast and effective flame activation route to enhance the charge collection properties of ZFO.First,high-temperature flame(>1300℃)facilitated surface and grain boundary diffusions,increasing the grain size and connectivity of the ZFO nanoparticles.Second,the reducing atmosphere of the flame enabled the formation of surface defects(oxygen vacancy and Fe^(2+)),thereby increasing the charge carrier density and surface adsorption sites.Significantly,these two factors promoted charge transport and transfer kinetics,resulting in a 10-fold increase in the photocurrent density over the unactivated ZFO.Furthermore,we deposited a thin Al_(2)O_(3)overlayer to passivate the ZFO surface and then the NiFeOx oxygen evolution catalyst(OEC)to expedite hole injection into the electrolyte.This surface passivation and OEC deposition led to a remarkable photocurrent density of~1 mA/cm^(2)at 1.23 V versus the reversible hydrogen electrode,which is the highest value among all reported ZFO photoanodes.Notably,the NiFeOx/Al_(2)O_(3)/F-ZFO photoanode achieved excellent photocurrent stability over 55 h(96%retention)and superior faradaic efficiency(FE>94%).Our flame activation method is also effective in improving the photocurrent densities of other spinel ferrites:CuFe_(2)O_(4)(93 times),MgFe_(2)O_(4)(16 times),and NiFe_(2)O_(4)(12 times).

Unique hollow heterostructured CdS/Cd_(0.5)Zn_(0.5)S-Mo_(1-x)W_(x)S_(2):Highly-improved visible-light-driven H_(2) generation via synergy of Cd_(0.5)Zn_(0.5)S protective shell and defect-rich Mo_(1-x)W_(x)S_(2) cocatalyst

Photocatalytic water splitting for hydrogen(H_(2))production is a green sustainable technology,in which highly-efficient steady photocatalysts are fundamentally required.In this work,unique CdS/Cd_(0.5)Zn_(0.5)S-M0_(1-x)W_(x)S_(2) photocatalyst constructed by CdS hollow nano-spheres with successively surface-modified Cd_(0.5)Zn_(0.5)S shell and defect-rich MO_(1-x)W_(x)S_(2) ultrathin nanosheets was reported for the first time.Interestingly,the Cd_(0.5)Zn_(0.5)S shell could greatly enhance the photo-stability and reduce the carrier recombination of CdS.Meanwhile,enriching active sites and accelerating charge transfer could be achieved via anchoring defect-rich Mo_(1-x)W_(x)S_(2) onto CdS/Cd_(0.5)Zn_(0.5)S hollow heterostructures.Specifically,the optimized CdS/Cd_(0.5)Zn_(0.5)S-Mo_(1-x)W_(x)Sa(6 h Cd_(0.5)Zn_(0.5)S-coating,7 wt.%Mo_(1-x)W_(x)S_(2),x=0.5)hybrid delivered an exceptional H_(2) generation rate of 215.99 mmol·g^(-1)·h^(-1),which is approximately 502,134,and 23 times that of pure CdS,CdS/Cd_(0.5)Zn_(0.5)S,and 3 wt.%Pt-loaded CdS/Cd_(0.5)Zn_(0.5)S,respectively.Remarkably,a high H_(2) evolution reaction(HER)apparent quantum yield(AQY)of 64.81%was obtained under 420-nm irradiation.In addition,the CdS/Cd_(0.5)Zn_(0.5)S-Mo_(1-x)W_(x)S_(2) was also durable for H2 production under long-term irradiation.This work provides valuable inspirations to rational design and synthesis of efficient and stable hybrid photocatalysts for solar energy conversion.

自体骨与富血小板纤维蛋白修复牙槽骨重度缺损

背景:有研究将富血小板纤维蛋白与自体骨联合应用于牙周骨缺损治疗取得了良好效果,但二者联合治疗牙槽骨重度缺损的研究目前较为匮乏。目的:观察自体骨移植与富血小板纤维蛋白联合修复牙槽骨重度缺损的效果。方法:选择2022年4月至2023年2月衡水市人民医院收治的102例牙槽骨重度缺损患者,采取随机数字表法分为对照组(n=51)与观察组(n=51),两组患者均进行引导性组织再生手术,对照组术中采用自体骨填充骨缺损,观察组术中采用自体富血小板纤维蛋白与自体骨填充骨缺损。观察两组临床疗效、手术前后牙齿松动度、牙周微生态环境(探诊深度、临床附着丧失、出血指数)、牙槽骨高度及密度、龈沟液指标(转化生长因子β、丝氨酸蛋白酶抑制剂、基质金属蛋白酶3)变化及不良反应情况。结果与结论:术后6个月,两组治疗有效率比较差异无显著性意义(P> 0.05);观察组患者术后3,6个月的牙齿松动度及牙周探诊深度、临床附着丧失、出血指数均低于对照组(P <0.05),术后6个月的牙槽骨高度高于对照组(P <0.05),术后3,6个月的龈沟液转化生长因子β水平高于对照组(P <0.05),术后3,6个月的龈沟液丝氨酸蛋白酶抑制剂、基质金属蛋白酶3水平均低于对照组(P <0.05)。结果提示:在引导性组织再生手术中,采用自体富血小板纤维蛋白与自体骨联合填充可改善牙槽骨重度缺损患者的牙周微生态环境、减轻牙龈组织炎症、促进牙槽骨组织再生与修复、降低牙齿松动度。

一步离心法制备富血小板凝胶修复颅骨外露创面的应用研究

目的探讨一步离心法制备富血小板凝胶(PRG)治疗头皮缺损伴颅骨外露创面的临床效果。方法回顾性分析2018年9月—2022年3月重庆市急救医疗中心创伤科收治的14例头皮缺损伴颅骨外露创面,男性12例,女性2例;年龄43~86岁,平均62.8岁;创面面积3.0 cm×4.0 cm~7.0 cm×6.0 cm,常规治疗4周创面仍未愈合。采集患者外周静脉血通过一步离心法制备PRG。治疗前常规行头皮清创,清创完成后直接将PRG覆盖于创面表面,凝胶表面再覆盖油纱,最外层利用水凝胶敷料封闭创面。每3d更换新的PRG直至创面全部愈合。测量PRG长度、评估血小板浓度变化,记录创面愈合时间和治疗次数。检测治疗前及治疗后3dVAS、WBC、CRP、PCT及局部皮温。结果一步离心法所制备的PRG长度(3.09±0.09)cm,血小板浓度提高(2.43±0.07)倍。经5~14次自体PRG治疗后,患者创面全部愈合,平均治疗(8.9±2.4)次,平均创面愈合时间(26.8±7.2)d。治疗前后患者VAS、WBC、CRP、降钙素原(PCT)以及局部皮温比较差异无统计学意义(P>0.05)。结论真空采血管一步离心法能够成功制备富血小板凝胶,并能够促进头皮缺损伴颅骨外露创面的愈合。

A-PRF促进兔膝关节骨软骨损伤愈合的观察

目的·探讨改良型富血小板纤维蛋白(advanced platelet-rich fibrin,A-PRF)在骨软骨再生中的作用。方法·获取新西兰兔骨髓间充质干细胞(bone-marrow mesenchymal stem cells,BMSCs)和膝关节软骨细胞;通过低速离心兔心脏血液获得A-PRF。采用光学显微镜观察A-PRF的组织学结构;ELISA法检测A-PRF中生长因子,包括血小板衍生生长因子、转化生长因子-β、胰岛素样生长因子、血管内皮生长因子、表皮生长因子和成纤维细胞生长因子的释放;采用活/死细胞双染法及MTT法检测A-PRF对兔BMSCs细胞毒性及增殖情况的影响;采用实时荧光定量聚合酶链反应(qRT-PCR)检测A-PRF对兔BMSCsⅡ型胶原蛋白、聚集蛋白聚糖、碱性磷酸酶(ALP)和骨钙素(OCN)基因表达的影响;使用transwell小室测定A-PRF对于兔BMSCs以及软骨细胞迁移能力的影响。建立兔膝关节骨软骨缺损模型,将18只兔随机分为3组:A-PRF组(n=6)在缺损处植入A-PRF;A-PRF+BMSCs组(n=6)植入接种兔BMSCs的A-PRF;对照组(n=6)不进行植入操作。术后12周处死兔,采用苏木精-伊红(H-E)、甲苯胺蓝和番红O-固绿染色进行膝关节标本的组织学观察,并根据膝关节的表面形态学与组织学情况,采用国际软骨修复协会(International Cartilage Repair Society,ICRS)评分系统进行宏观与组织学评分。结果·A-PRF具有松散的网络结构,可以缓慢释放生长因子。加入A-PRF后,未观察到其对兔BMSCs具有细胞毒性;在加入A-PRF后24、48和72 h,BMSCs的增殖能力均明显升高(均P<0.05),成软骨相关基因Ⅱ型胶原蛋白、聚集蛋白聚糖,以及成骨相关基因ALP和OCN均显著上调(均P<0.05)。加入A-PRF后,兔BMSCs与软骨细胞的迁移能力均显著增强(均P<0.05),且兔BMSCs的迁移能力显著高于软骨细胞(P=0.025)。在兔膝关节缺损模型中,观察关节表面形态,可见A-PRF组和A-PRF+BMSCs组缺损均基本恢复,而对照组仅有软组织覆盖。在ICRS宏观评分方面,A-PRF组与A-PRF+BMSCs组的差异无统计学意义,但2组评分均显著高于对照组(均P<0.05)。组织学观察显示,A-PRF组和A-PRF+BMSCs组均产生骨软骨修复,但A-PRF组软骨更加成熟,对照组则形成纤维修复。在ICRS组织学评分方面,A-PRF组与A-PRF+BMSCs组的差异无统计学意义,但2组评分均显著高于对照组(均P<0.05)。结论·自体A-PRF具有良好的生物相容性和促进BMSCs增殖的能力,在体外和体内均可促进软骨和软骨下骨的修复。

高效Li-CO_(2)电池用富缺陷Co-N-C纳米片电极的制备

采用原位生长-模板保护-裂解组装策略,对双金属类沸石咪唑骨架材料(ZIFs)前驱体进行结构调控,成功制备Co-N_(x)、N-C活性位点及缺陷共存的二维钴-氮-碳纳米片(Co-N-C NFs)催化剂。Co-N-C NFs耦合了内在的Co-N-C的电子结构和外在的富缺陷的二维片层结构,为锂-二氧化碳电池(LCB)提供了有利的气-液-固三相反应界面;纳米薄片彼此交互,构建出有利于CO_(2)吸脱附、锂离子和电子迁移输运路径以及便于产物寄宿的空间结构。基于Co-N-C NFs催化剂正极构筑LCB电池,电池表现出优异的电化学性能,放电容量达到2880μAh/cm^(2),在100μA/cm^(2)的大电流密度下,放-充电平台维持在2.60 V和4.40 V,且能稳定工作超1480 h。

富血小板纤维蛋白联合羟基磷灰石治疗牙周骨内缺损的Meta分析

目的:从临床指标方面系统评价富血小板纤维蛋白(PRF)与羟基磷灰石(HA)联用治疗牙周骨内缺损的疗效。方法:计算机检索PubMed、the Cochrane Library、Web of Science、维普、万方数据库、中国知网,检索关于PRF和HA联合治疗与PRF或HA单独治疗牙周骨内缺损的随机对照实验(RCT),检索时限从建库至2023年6月。结果:最终纳入9个RCT,354个牙周骨内缺损位点。Meta分析显示,PRF与HA联合应用组与PRF组和HA组的探诊深度(PD)、临床附着丧失(CAL)、菌斑指数(PI)、牙龈指数(GI)的改变量差异均有统计学意义(P<0.05)。结论:目前的研究证据表明,PRP与HA联合应用治疗牙周骨内缺损均优于单用PRF或HA,由于纳入研究数量及质量的限制,还亟待更多高质量文献的证明。

富水砂层基坑止水缺陷高宽比对漏水漏砂的影响

在富水砂层地质条件下,基坑支护常因止水缺陷导致水土大量流失,进而引发地表沉降。目前有关止水缺陷导致基坑漏水漏砂灾害方面的研究还有待深入。本文以江西省南昌市临近赣江某地铁基坑砂土为研究对象,考虑基坑止水缺陷高宽比因素,通过可视化室内实验装置研究基坑缺陷漏水漏砂灾害的演化过程,并利用PFC3D软件进行模拟对比分析,探究几何形态和微观变化过程。结果表明:止水缺陷高宽比越大,漏水漏砂发展速度越快,颗粒流失速率越大,砂土颗粒受侵蚀范围越大;缺陷高宽比由1:1增加至2:1时,颗粒损失个数由2673扩大至40127,土拱形成时间从60万步发展至无法形成土拱,存在出现土拱时的临界缺陷高宽值。数值模拟过程中的配位数波动表明,漏水漏砂过程中细颗粒与粗颗粒骨架之间一直产生着剧烈碰撞,水土的流失导致孔隙率与渗透系数的增加,进而加剧漏水漏砂现象。

超声检测识别CFRP复合材料PTFE夹杂与富树脂缺陷

针对碳纤维增强复合材料(Carbon fiber reinforced polymer,CFRP)缺陷试样制作困难且不同夹杂缺陷难识别的问题,采用仿真与试验相结合的方法,开展聚四氟乙烯(PTFE)夹杂与富树脂缺陷超声检测研究。首先建立考虑CFRP层结构弹性各向异性的多向层合板超声反射法有限元模型,对比模拟与试验得到的A扫描时域信号,证明了模型的有效性。在CFRP层合板内部设置宽度6 mm,厚度0.03~0.40 mm的PTFE夹杂和厚度0.03~0.85 mm的富树脂缺陷,模拟得到超声A扫描信号,分析比较两种缺陷厚度变化对超声信号幅值最大值和波形峭度因子的影响。结果显示,随着缺陷厚度增加,PTFE夹杂及富树脂缺陷信号的幅值最大值和峭度因子均呈现先上升后下降最后趋于稳定的趋势,但富树脂缺陷信号幅值最大值低于PTFE夹杂,其峭度因子随厚度变化滞后于PTFE夹杂。

富血小板纤维蛋白对骨再生的作用研究

目的研究富血小板纤维蛋白(PRF)在骨再生中的作用。方法选取24只新西兰大白兔,随机分为正常组、模型组、研究组及材料对照组,每组6只,制作兔腓骨骨缺损模型。正常组不做处理;模型组只造模;研究组将PRF和明胶海绵植入模型中;材料对照组只植入明胶海绵。6周后观察骨缺损处大体形态并进行X线摄片、HE染色及免疫组化,对结果进行统计学分析。结果大体观察X线摄片示正常组无异常;模型组有少量骨痂形成;研究组有规整骨痂形成;材料对照组有不规则骨痂形成。HE染色示正常组骨小梁完整;模型组未见明显骨小梁再生;研究组骨小梁再生明显;材料对照组部分骨小梁再生。ELISA结果示研究组、材料对照组较模型组骨形态发生蛋白2(BMP-2)显著升高,差异有统计学意义(P<0.05);血管内皮生长因子(VEGF)升高,差异无统计学意义(P>0.05);研究组较材料对照组BMP-2显著升高,差异具有统计学意义(P<0.05),VEGF升高但差异无统计学意义(P>0.05)。CD34结果示研究组和材料对照组CD34含量显著高于正常组和模型组,研究组和材料对照组之间差异有统计学意义(P<0.05)。结论PRF通过升高BMP-2和VEGF的表达,增加骨缺损处的血管及新骨的生成来促进骨缺损的修复。

富血小板血浆与同种异体骨复合对兔感染性骨缺损处血管化作用及成骨效果的影响

目的探讨富血小板血浆(PRP)与同种异体骨(AB)复合对兔感染性骨缺损处血管化作用及成骨效果的影响。方法选择健康SPF级新西兰大白兔140只,兔龄12~16周,体质量2.01~2.10 kg。其中20只动物用于制备PRP,通过低速离心法制备PRP。构建新西兰大白兔感染性骨缺损模型;动物实验分为4组及处理,即空白对照组(Control组,不做处理)、植入PRP组(PRP组,植入PRP)、植入AB组(AB组,植入AB)、植入PRP复合AB组(PRP+AB组,植入PRP和AB),每组30只。分别在1周、4周、12周时行X射线检查、Micro CT检查,并处死动物,采用酶联免疫吸附分析实验检测动物血清中C-反应蛋白(CRP)的水平;采用聚合酶链式反应(PCR)检测骨缺损区域中碱性磷酸酶(ALP)、骨钙素(OCN)、血管内皮生长因子(VEGF)和血管生成素1(ANGPT1)的mRNA的表达,免疫组化检测ALP和OCN的表达,免疫荧光检测ANGPT1、VEGF的表达。结果Control组样本在1、4、12周时均存在明显的不同程度的骨缺损,并且骨缺损无愈合、无好转的趋势。PRP组、AB组、PRP+AB组大白兔的骨缺损区域出现不同程度的愈合,植入材料与骨结合良好、致密,未出现明显坏死骨;尤以PRP+AB组骨缺损修复最为明显。X射线评分与同时点Control组(1、4、12周3.07分±0.15分、4.21分±0.28分、8.03分±0.23分)相比,PRP组、AB组、PRP+AB组骨缺损区域X射线评分(PRP组3.72分±0.21分、5.14分±0.37分、9.27分±0.22分;AB组4.65分±0.26分、6.49分±0.43分、10.34分±0.29分;PRP+AB组5.31分±0.35分、7.25分±0.51分、11.19分±0.64分)明显升高,且PRP+AB组X射线评分更高;差异均有统计学意义(均P<0.05)。与同时点Control组(1、4、12周0.01±0.01、0.02±0.02、0.05±0.03)相比,PRP组、AB组、PRP+AB组骨缺损区域BV/TV(PRP组1、4、12周BV/TV 0.02±0.02、0.06±0.03、0.09±0.04;AB组1、4、12周0.02±0.01、0.07±0.04、0.16±0.03;PRP+AB组1、4、12周0.04±0.03、0.13±0.05、0.24±0.07)明显升高,且PRP+AB组骨缺损区域BV/TV更高;差异均有统计学意义(均P<0.05)。病理组织学评分有同样的结果。与同时点Control组(1、4、12周18.29 mg/L±0.44 mg/L、15.04 mg/L±0.48 mg/L、13.91 mg/L±0.53 mg/L)相比,PRP组、AB组、PRP+AB组大白兔血清中CRP含量(PRP组1、4、12周17.04 mg/L±0.37 mg/L、12.32 mg/L±0.52 mg/L、10.22 mg/L±0.47 mg/L;AB组1、4、12周16.25 mg/L±0.31 mg/L、10.21 mg/L±0.36 mg/L、8.24 mg/L±0.35 mg/L;PRP+AB组1、4、12周15.41 mg/L±0.28 mg/L、8.91 mg/L±0.49 mg/L、5.16 mg/L±0.38 mg/L)明显降低,ALP、OCN、ANGPT1、VEGF mRNA和其蛋白表达水平明显升高,且PRP+AB组大白兔血清中CRP含量降低更显著,ALP、OCN、ANGPT1、VEGF mRNA和其蛋白表达水平升高更明显;差异均有统计学意义(均P<0.05)。结论PRP复合AB能明显促进兔感染性骨缺损区域中ALP和OCN、ANGPT1和VEGF的表达,推动骨缺损处的成骨和成血管效应。