热敏灸治疗颈型颈椎病的Meta分析及GRADE证据等级评价

目的系统评价热敏灸及其综合疗法用于颈型颈椎病的临床效果,为热敏灸治疗颈型颈椎病提供更好的证据来源。方法收集国内外各大数据库热敏灸及其综合疗法用于颈型颈椎病的随机对照试验(RCT),通过Revman 5.3软件进行Meta分析,按照GRADE标准对结局指标进行证据质量评价。结果纳入9篇文献共855例患者,Meta分析结果提示:热敏灸及其综合疗法组在提高总有效率(RR=1.19,P<0.01)和治愈率(RR=1.73,P<0.01)、降低视觉模拟量表(VAS)评分(SMD=-0.73,P<0.01)、简化McGill疼痛问卷(SF-MPQ)评分(SMD=-1.28,P<0.05)以及NPQ颈痛量表评分(SMD=-0.81,P<0.05)方面都优于对照组;GRADE证据等级评价提示:前三者为低质量证据,后二者为极低质量证据。结论热敏灸及其综合疗法用于颈型颈椎病在提高临床效果、镇痛以及改善患者生活质量方面更具优势。

刮痧改善腰椎间盘突出疼痛症状的系统评价及GRADE证据质量评价

目的系统评价刮痧干预腰椎间盘突出疼痛症状的疗效与安全性,为其临床治疗提供循证依据。方法计算机检索自建库到2022年8月29日前公开发表在中国知网、万方、维普、中国生物医学文献服务系统、PubMed、Embase、Web of Science、The Cochrane Library数据库,收集关于刮痧干预腰椎间盘突出的随机对照试验(Randomized controlled trial,RCT)。文章由两名研究者独立筛选,根据Cochrane Reviewers Handbook 6.2的偏倚风险评估工具对纳入文献进行质量评价,应用RevMan 5.4软件对纳入文献的结局指标进行Meta分析,并采用GRADE系统对结局指标进行证据质量等级评价。结果最终纳入10篇RCT,共1087例患者。Meta分析结果显示:刮痧试验组治疗腰椎间盘突出患者在疼痛VAS评分[MD=-1.11,95%CI(-1.58,-0.64),P<0.00001]、日本骨科协会(JOA)评分[MD=4.47,95%CI(3.76,5.17),P<0.00001]、临床有效率[relative risk(RR)=1.13,95%CI(1.08,1.19),P<0.00001]和护理满意度[RR=1.21,95%CI(1.09,1.34),P=0.0005]方面,明显优于对照组,差异均有统计学意义(P<0.00001)。本文结局指标的证据质量为极低。结论当前证据表明,刮痧治疗腰椎间盘突出患者的疼痛症状具有良好临床疗效,并有助于提高临床护理满意度。由于部分结局证据质量较低,有待严谨的多中心、大样本随机对照试验来进一步验证其有效性,提升临床证据。

穴位埋线治疗功能性便秘疗效与安全性Meta分析及GRADE评价

目的:系统评价穴位埋线治疗功能性便秘(FC)的疗效和安全性及纳入证据的质量,以期为临床决策提供循证医学证据。方法:检索中国知网(CNKI)、万方知识服务平台(WANFANG)、维普中文期刊数据库(VIP)、中国生物医学文献服务系统(SinoMed)、Embase、PubMed和Cochrane Library数据库,搜集穴位埋线治疗FC的随机对照试验(RCT),检索时间均从建库至2023年10月16日。由2名研究者独立完成文献筛选、资料提取及偏倚风险评估,采用RevMan 5.4软件进行Meta分析,并采用GRADE评价方法对各项结局指标进行证据质量评价。结果:最终共纳入19项RCT,包括1673例患者。Meta分析结果显示,与对照组比较,穴位埋线治疗FC可提高总有效率[RR=1.23,95%CI=(1.17,1.29),P<0.00001],增加完全自发排便(CSBM)次数[MD=0.61,95%CI=(0.11,1.10),P=0.02],改善粪便性状[MD=0.53,95%CI=(0.31,0.76),P<0.00001]及排便困难[MD=-0.71,95%CI=(-1.03,-0.40),P<0.00001],缩短排便时间[MD=-0.50,95%CI=(-0.72,-0.29),P<0.00001],改善便秘生活质量评估量表(PAC-QOL)评分[MD=-7.72,95%CI=(-12.83,-2.61),P<0.003];两组不良反应发生率比较,差异无统计学意义[RR=0.37,95%CI=(0.10,1.38),P=0.14]。GRADE证据级别评价结果显示:总有效率为中级别证据质量,不良反应发生率、粪便性状评分、排便困难评分为低级别证据质量,CSBM次数、排便时间、PACQOL评分为极低级别证据质量。结论:穴位埋线治疗FC具有一定的疗效,可改善便秘相关症状,且未增加不良反应发生率。但纳入研究质量总体偏低,上述结论尚需开展更多高质量的研究予以验证。

腕踝针干预术后疼痛疗效的Meta分析和Grade评价

目的运用循证医学方法对腕踝针干预术后疼痛的疗效和安全性进行系统评价和Grade评价。方法计算机检索中国知网、万方、维普、中国生物医学文献数据库、PubMed、Embase、Web of Science、Cochrane Library中关于腕踝针干预术后疼痛的随机对照试验,检索时限为建库至2023年10月。采用RevMan 5.4软件进行Meta分析。结果纳入23篇文献,共计1968例患者,Meta分析结果显示,与常规治疗相比,腕踝针能够提高术后疼痛患者的总有效率[OR=4.42,95%CI(2.60,7.50),P<0.001],术后镇痛泵药量使用减少[MD=-9.03,95%CI(-12.09,-5.98),P<0.001],术后疼痛评分降低[MD=-1.39,95%CI(-1.68,-1.09),P<0.001],可减少不良反应发生率[RR=0.40,95%CI(0.32,0.48),P<0.001]以及临床满意度[OR=3.94,95%CI(2.40,6.48),P<0.001]。Grade证据分级结果显示:总有效率、不良反应发生率和临床满意度3项结局指标为中等质量证据,VAS评分指标为低质量证据,镇痛泵药量使用指标为极低质量证据。结论腕踝针可提高总有效率,减少术后镇痛药用量,不良反应少,安全性高,为患者提供了一种安全有效的镇痛方式。

乌梅丸加减治疗帕金森病的Meta分析及GRADE评价

目的 系统评估乌梅丸加减治疗帕金森病(parkinson's disease, PD)的疗效和安全性。方法 计算机检索Cochrane Library、EMBASE、Web of Science、PubMed、CNKI、CBM等中英文数据库及临床试验中心,关于乌梅丸治疗PD的临床随机对照试验(randomized controlled trial, RCT),检索时限从建库至2023年4月。进行资料整理及数据提取等工作后,最终纳入8项研究,治疗组(乌梅丸)和对照组分别纳入226例。使用RevMan 5.3及stata14软件进行荟萃分析,使用GRADEpro GDT评估各项结局指标的证据质量。结果 治疗组降低PD统一评分量表(unified Parkinson's disease rating scale, UPDRS)的各项量表积分较对照组明显,其中在改善UPDRS Ⅰ、Ⅲ、Ⅳ方面具有统计学意义,结果分别为[MD=-0.769,95%CI(-1.213~-0.324),P=0.001]、[MD=-2.211,95%CI(-2.713~-1.708),P=0]、[MD=-0.526,95%CI(-1.041~-0.012),P=0.045]。2组在改善UPDRS总分方面差异无统计学意义[MD=3.964,95%CI(-9.465~17.392),P=0.563]。治疗组能显著提高治疗有效率,差异具有统计学意义[RR=1.709,95%CI(1.361~2.145),P=0]。各项研究均未发现不良事件发生及与治疗有关的检验指标异常。GRADE证据质量分级结果为UPDRS Ⅰ、UPDRS Ⅲ、UPDRS Ⅳ及有效率方面均为中等级别,UPDRS Ⅱ为低等级,UPDRS总分为非常低。结论 乌梅丸加减的应用对PD的治疗有一定效果,且具有良好的安全性。

医院药学指南制定中的证据与推荐意见GRADE系统评级方法及应用

目前,国际上存在多种证据与推荐意见分级系统,对临床医务工作者阅读指南证据和推荐意见造成困扰。证据推荐分级的评估、制定与评价(GRADE)系统目前是全球使用最为广泛的证据与推荐意见分级系统,本文简单地介绍GRADE系统证据质量评级及影响推荐意见形成的4个主要因素,并结合中国医院药学界发起制定的、在国际上发表的几部药学指南举例阐述,以帮助临床医务工作者了解GRADE系统,以批判性思维运用指南证据和推荐意见指导临床实践行为。

补肾方剂改善高龄女性自然妊娠结局的Meta分析及GRADE质量评价

目的系统评价补肾方剂改善高龄女性自然妊娠结局的临床疗效和安全性。方法检索中国知网、万方数据库、维普数据库、SinoMed、PubMed、Web of Science、Cochrane Library、Embase等数据库建库至2022年6月收录的补肾方剂改善高龄女性自然妊娠结局的随机对照研究(RCT)。运用偏倚风险工具进行质量评估,使用RevMan软件进行Meta分析。结果共纳入14篇RCT。Meta分析结果显示:补肾方剂联合西药治疗在提高妊娠率[RR=1.71,95%CI(1.45,2.01),P<0.00001]、降低卵泡刺激素(FSH)水平[SMD=-1.63,95%CI(-2.84,-0.43),P=0.008]、提高雌二醇(E_(2))水平[SMD=3.97,95%CI(1.76,6.17),P=0.0004]、增加排卵期子宫内膜厚度[SMD=2.12,95%CI(1.07,3.18),P<0.0001]方面均优于西药组;且补肾方剂单独使用在提高妊娠率[RR=1.94,95%CI(1.31,2.88),P=0.001]、降低FSH水平[SMD=-0.48,95%CI(-0.74,-0.22),P=0.0003]方面也具有显著疗效。结论与西医治疗比较,补肾方剂可以显著改善高龄女性自然妊娠结局,且不良反应较少,但仍需更多高质量、大样本、多中心的RCT予以验证。

PTGD后择期腹腔镜胆囊切除治疗对GradeⅡ急性胆囊炎ACTH、MPO及Cor水平的影响

目的分析PTGD后择期LC治疗对GradeⅡ急性胆囊炎ACTH、MPO及Cor水平的影响。方法选取2021年12月至2023年5月安徽中科庚玖医院收治的急性胆囊炎患者121例,根据治疗方案分为三组,即甲组(急诊行LC治疗,未行PTGD)38例、乙组(PTGD引流管拔出后72 h后行LC,早期)43例和丙组(PTGD引流管拔出后14~30 d后行LC,晚期)40例。对比三组手术情况、炎症因子、肝功能、ACTH、MP、Cor水平及并发症发生率。结果甲组LC手术时长、术后卧床时长及住院天数均长于丙组、乙组,失血量、中转开腹率高于丙组、乙组,差异有统计学意义(P<0.05);丙组LC手术时长、术后卧床时长及住院天数均长于乙组,差异具有统计学意义(P<0.05)。LC术后1 d hs-CRP、PCT、IL-6、ST、ALT、ALP、ACTH、MPO及Cor:甲组>丙组>乙组,差异有统计学意义(P<0.05)。并发症发生率:甲组>丙组>乙组,差异有统计学意义(P<0.05)。结论PTGD后择期LC治疗对GradeⅡ急性胆囊炎ACTH、MPO及Cor水平影响小,且并发症低;而PTGD后早期行LC能有效改善肝功能、炎症因子,且术后应激反应更低,值得临床推广。

温针灸治疗原发性痛经有效性和安全性的系统评价及GRADE评价

目的:评价温针灸治疗原发性痛经的有效性和安全性。方法:根据PRISMA指南进行系统综述和荟萃分析。收集PubMed、Web of Science、EMBASE、Cochrane Library、中国知网、维普、万方、中国生物医学数据库自建库至2023年5月的随机对照试验。使用Review Manager 5.4对所有获得的数据进行分析。结果:温针灸治疗原发性痛经在提高临床疗效{风险比(RR)=1.21,95%置信区间(CI)[1.16,1.25],P<0.00001},改善阻力指数(RI){均数差(MD)=-0.14,95%CI[-0.19,-0.08],P<0.00001}、搏动指数(PI)(MD=-0.55,95%CI[-0.69,-0.40],P<0.00001)、β-内啡肽(β-EP){标准化均数差(SMD)=1.36,95%CI[0.90,1.82],P<0.00001}、痛经证候积分(MD=-1.82,95%CI[-2.77,-0.87],P=0.0002)、疼痛视觉模拟评分法(VAS)评分(MD=-1.16,95%CI[-1.48,-0.83],P<0.00001)方面的作用优于单独的常规治疗,并且在不良反应发生率(P=0.01)方面低于对照组。证据质量等级评价结果显示临床疗效为中级,其他多为低级。结论:温针灸治疗原发性痛经的疗效明确,并且具有一定的安全性。

基于GRADE证据质量评级的小青龙汤治疗过敏性鼻炎系统评价与试验序贯分析

目的:系统评价小青龙汤治疗过敏性鼻炎的临床疗效和安全性,分析证据质量,验证研究结果的可信度。方法:检索中国知网、万方数据库、维普中文期刊服务平台、中国生物医学文献数据库、PubMed、Web of Science、The Cochrane Library等数据库中从建库至2023年7月31日小青龙汤治疗过敏性鼻炎的文献。对所得文献进行筛选、资料提取和评估,使用RevMan5.3软件进行Meta分析,使用Stata 16.0软件进行敏感性分析,使用TSA V0.9软件进行试验序贯分析,使用GRADEpro软件对结局指标进行证据质量评级。结果:纳入20篇随机对照试验(Randomized Controlled Trial,RCT),患者1 723例。Meta分析结果显示,试验组比对照组有更好的临床疗效[相对危险度(RR)=1.19,95%置信区间(CI)(1.14,1.25),P <0.000 01]。试验组在降低半年复发率[RR=0.50, 95%CI (0.32,0.78),P=0.002],降低鼻塞[加权均数差(WMD)=-0.20,95%CI(-0.26,-0.13),P <0.000 01]、流涕[WMD=-0.09,95%CI(-0.15,-0.03),P=0.004]、喷嚏[WMD=-0.21,95%CI(-0.28,-0.13),P <0.000 01]等症状积分及体征积分[WMD=-0.25,95%CI(-0.37,-0.14),P <0.000 1]和血清白细胞介素-4水平[WMD=-4.23,95%CI(-7.22,-1.23),P=0.006]方面均优于对照组。试验序贯分析进一步肯定了小青龙汤治疗过敏性鼻炎的疗效。GRADE证据质量分级显示,临床有效率、不良反应发生率、鼻痒积分为低质量证据,其余均为极低质量证据。结论:小青龙汤治疗过敏性鼻炎安全有效,但需要纳入更高质量的临床研究进一步验证。

Tree‑Inspired Structurally Graded Aerogel with Synergistic Water,Salt,and Thermal Transport for High‑Salinity Solar‑Powered Evaporation

Solar-powered interfacial evaporation is an energy-efficient solution for water scarcity.It requires solar absorbers to facilitate upward water transport and limit the heat to the surface for efficient evaporation.Furthermore,downward salt ion transport is also desired to prevent salt accumulation.However,achieving simultaneously fast water uptake,downward salt transport,and heat localization is challenging due to highly coupled water,mass,and thermal transport.Here,we develop a structurally graded aerogel inspired by tree transport systems to collectively optimize water,salt,and thermal transport.The arched aerogel features root-like,fan-shaped microchannels for rapid water uptake and downward salt diffusion,and horizontally aligned pores near the surface for heat localization through maximizing solar absorption and minimizing conductive heat loss.These structural characteristics gave rise to consistent evaporation rates of 2.09 kg m^(-2) h^(-1) under one-sun illumination in a 3.5 wt%NaCl solution for 7 days without degradation.Even in a high-salinity solution of 20 wt%NaCl,the evaporation rates maintained stable at 1.94 kg m^(-2) h^(-1) for 8 h without salt crystal formation.This work offers a novel microstructural design to address the complex interplay of water,salt,and thermal transport.

Thermal transport in composition graded silicene/germanene heterostructures

Through equilibrium and non-equilibrium molecular dynamics simulations,we have demonstrated the inhibitory effect of composition graded interface on thermal transport behavior in lateral heterostructures.Specifically,we investigated the influence of composition gradient length and heterogeneous particles at the silicene/germanene(SIL/GER)heterostructure interface on heat conduction.Our results indicate that composition graded interface at the interface diminishes the thermal conductivity of the heterostructure,with a further reduction observed as the length increases,while the effect of the heterogeneous particles can be considered negligible.To unveil the influence of composition graded interface on thermal transport,we conducted phonon analysis and identified the presence of phonon localization within the interface composition graded region.Through these analyses,we have determined that the decrease in thermal conductivity is correlated with phonon localization within the heterostructure,where a stronger degree of phonon localization signifies poorer thermal conductivity in the material.Our research findings not only contribute to understanding the impact of interface gradient-induced phonon localization on thermal transport but also offer insights into the modulation of thermal conductivity in heterostructures.

Parametric resonance of axially functionally graded pipes conveying pulsating fluid

Based on the generalized Hamilton's principle,the nonlinear governing equation of an axially functionally graded(AFG)pipe is established.The non-trivial equilibrium configuration is superposed by the modal functions of a simply supported beam.Via the direct multi-scale method,the response and stability boundary to the pulsating fluid velocity are solved analytically and verified by the differential quadrature element method(DQEM).The influence of Young's modulus gradient on the parametric resonance is investigated in the subcritical and supercritical regions.In general,the pipe in the supercritical region is more sensitive to the pulsating excitation.The nonlinearity changes from hard to soft,and the non-trivial equilibrium configuration introduces more frequency components to the vibration.Besides,the increasing Young's modulus gradient improves the critical pulsating flow velocity of the parametric resonance,and further enhances the stability of the system.In addition,when the temperature increases along the axial direction,reducing the gradient parameter can enhance the response asymmetry.This work further complements the theoretical analysis of pipes conveying pulsating fluid.

Biomimetic MXene membranes with negatively thermo-responsive switchable 2D nanochannels for graded molecular sieving

Negatively thermo-responsive 2D membranes,which mimic the stomatal opening/closing of plants,have drawn substantial interest for tunable molecular separation processes.However,these membranes are still restricted significantly on account of low water permeability and poor dynamic tunability of 2D nanochannels under temperature stimulation.Here,we present a biomimetic negatively thermo-responsive MXene membrane by covalently grafting poly(N-isopropylacrylamide)(PNIPAm)onto MXene nanosheets.The uniformly grafted PNIPAm polymer chains can enlarge the interlayer spacings for increasing water permeability while also allowing more tunability of 2D nanochannels for enhancing the capability of gradually separating multiple molecules of different sizes.As expected,the constructed membrane exhibits ultrahigh water permeance of 95.6 L m^(-2) h^(-1) bar^(-1) at 25℃,which is eight-fold higher than the state-of-the-art negatively thermoresponsive 2D membranes.Moreover,the highly temperature-tunable 2D nanochannels enable the constructed membrane to perform excellent graded molecular sieving for dye-and antibiotic-based ternary mixtures.This strategy provides new perspectives in engineering smart 2D membrane and expands the scope of temperature-responsive membranes,showing promising applications in micro/nanofluidics and molecular separation.

Dynamic Characteristics of Functionally Graded Timoshenko Beams by Improved Differential Quadrature Method

This study proposes an effective method to enhance the accuracy of the Differential Quadrature Method(DQM)for calculating the dynamic characteristics of functionally graded beams by improving the form of discrete node distribution.Firstly,based on the first-order shear deformation theory,the governing equation of free vibration of a functionally graded beam is transformed into the eigenvalue problem of ordinary differential equations with respect to beam axial displacement,transverse displacement,and cross-sectional rotation angle by considering the effects of shear deformation and rotational inertia of the beam cross-section.Then,ignoring the shear deformation of the beam section and only considering the effect of the rotational inertia of the section,the governing equation of the beam is transformed into the eigenvalue problem of ordinary differential equations with respect to beam transverse displacement.Based on the differential quadrature method theory,the eigenvalue problem of ordinary differential equations is transformed into the eigenvalue problem of standard generalized algebraic equations.Finally,the first several natural frequencies of the beam can be calculated.The feasibility and accuracy of the improved DQM are verified using the finite element method(FEM)and combined with the results of relevant literature.

A Hybrid Level Set Optimization Design Method of Functionally Graded Cellular Structures Considering Connectivity

With the continuous advancement in topology optimization and additive manufacturing(AM)technology,the capability to fabricate functionally graded materials and intricate cellular structures with spatially varying microstructures has grown significantly.However,a critical challenge is encountered in the design of these structures–the absence of robust interface connections between adjacent microstructures,potentially resulting in diminished efficiency or macroscopic failure.A Hybrid Level Set Method(HLSM)is proposed,specifically designed to enhance connectivity among non-uniform microstructures,contributing to the design of functionally graded cellular structures.The HLSM introduces a pioneering algorithm for effectively blending heterogeneous microstructure interfaces.Initially,an interpolation algorithm is presented to construct transition microstructures seamlessly connected on both sides.Subsequently,the algorithm enables the morphing of non-uniform unit cells to seamlessly adapt to interconnected adjacent microstructures.The method,seamlessly integrated into a multi-scale topology optimization framework using the level set method,exhibits its efficacy through numerical examples,showcasing its prowess in optimizing 2D and 3D functionally graded materials(FGM)and multi-scale topology optimization.In essence,the pressing issue of interface connections in complex structure design is not only addressed but also a robust methodology is introduced,substantiated by numerical evidence,advancing optimization capabilities in the realm of functionally graded materials and cellular structures.

火针治疗神经性皮炎的Meta分析及GRADE证据质量评价

目的:运用Meta分析系统评价火针治疗神经性皮炎的临床疗效。方法:计算机检索中国期刊全文数据库(CNKI)、重庆维普(VIP)、万方数据库(WanFang)、中国生物医学文献数据库(CBM)及Pubmed、Cochrane library等中英文数据库,时限设定为建库-2023年2月28日,检索火针治疗神经性皮炎的随机对照试验(Randomized controlled,RCT)相关文献。运用Cochrane风险偏倚评估工具对纳入研究的文献质量评估,再运用Revman5.4软件进行Meta分析,运用TSA0.9.5.10软件进行试验序贯分析,使用GRADE软件对主要结局指标的证据进行证据质量评级。结果:①共纳入18篇研究,1 662例患者,火针组840例,对照组822例;②Meta分析结果显示:火针组的临床有效率[OR=3.99,95%CI(2.81,5.68),Z=7.71,P<0.00 001]、复发率[OR=0.27,95%CI(0.11,0.68),Z=2.79,P=0.005)]均优于对照组;症状积分[MD=-1.49,95%CI(-2.25,-0.73),Z=3.85,P=0.0 001]、TNF-α水平[MD=-4.26,95%CI(-7.01,-1.51),Z=3.03,P=0.002]、IL-6水平[MD=-7.39,95%CI(-14.36,-0.42),Z=2.08,P=0.04]、IL-4水平[MD=-1.50,95%CI(-1.94,-1.06),Z=6.69,P<0.00 001]方面火针组均低于对照组;③火针组不良反应率整体低于对照组;④试验序贯分析显示:累计Z值穿过了传统界值和TSA界值,表示虽然累计的信息量未达到期望值,但不需要更多的试验,提前得到肯定的结论,结果较为可靠。结论:火针治疗神经性皮炎的具有明确的疗效,在症状积分和TNF-α、IL-6、IL-4水平表达等方面效果均优于对照组,安全性也较高,可为中医外治法治疗神经性皮炎的有效性提供相关证据。但因GRADE证据质量评级显示证据质量不理想,建议后续医务工作者可减少开展火针治疗神经性皮炎相关低质量试验,开展一些多中心、高质量的研究对结果加以佐证,从而避免科研和医疗资源的浪费。

Numerical Analysis of Permeability of Functionally Graded Scaffolds

In this work,we numerically study the hydrodynamic permeability of new-generation artificial porous materials used as scaffolds for cell growth in a perfusion bioreactor.We consider two popular solid matrix designs based on triply periodic minimal surfaces,the Schwarz P(primitive)and D(diamond)surfaces,which enable the creation of materials with controlled porosity gradients.The latter property is crucial for regulating the shear stress field in the pores of the scaffold,which makes it possible to control the intensity of cell growth.The permeability of functionally graded materials is studied within the framework of both a microscopic approach based on the Navier-Stokes equation and an averaged description of the liquid filtration through a porous medium based on the equations of the Darcy or Forchheimer models.We calculate the permeability coefficients for both types of solid matrices formed by Schwarz surfaces,study their properties concerning forward and reverse fluid flows,and determine the ranges of Reynolds number for which the description within the Darcy or Forchheimer model is applicable.Finally,we obtain a shear stress field that varies along the sample,demonstrating the ability to tune spatially the rate of tissue growth.

Exact solution for thermal vibration of multi-directional functionally graded porous plates submerged in fluid medium

An analytical method for analyzing the thermal vibration of multi-directional functionally graded porous rectangular plates in fluid media with novel porosity patterns is developed in this study.Mechanical properties of MFG porous plates change according to the length,width,and thickness directions for various materials and the porosity distribution which can be widely applied in many fields of engineering and defence technology.Especially,new porous rules that depend on spatial coordinates and grading indexes are proposed in the present work.Applying Hamilton's principle and the refined higher-order shear deformation plate theory,the governing equation of motion of an MFG porous rectangular plate in a fluid medium(the fluid-plate system)is obtained.The fluid velocity potential is derived from the boundary conditions of the fluid-plate system and is used to compute the extra mass.The GalerkinVlasov solution is used to solve and give natural frequencies of MFG porous plates with various boundary conditions in a fluid medium.The validity and reliability of the suggested method are confirmed by comparing numerical results of the present work with those from available works in the literature.The effects of different parameters on the thermal vibration response of MFG porous rectangular plates are studied in detail.These findings demonstrate that the behavior of the structure within a liquid medium differs significantly from that within a vacuum medium.Thereby,they offer appropriate operational approaches for the structure when employed in various mediums.

Transfer matrix method for free and forced vibrations of multi-level functionally graded material stepped beams with different boundary conditions

Functionally graded materials(FGMs)are a novel class of composite materials that have attracted significant attention in the field of engineering due to their unique mechanical properties.This study aims to explore the dynamic behaviors of an FGM stepped beam with different boundary conditions based on an efficient solving method.Under the assumptions of the Euler-Bernoulli beam theory,the governing differential equations of an individual FGM beam are derived with Hamilton’s principle and decoupled via the separation-of-variable approach.Then,the free and forced vibrations of the FGM stepped beam are solved with the transfer matrix method(TMM).Two models,i.e.,a three-level FGM stepped beam and a five-level FGM stepped beam,are considered,and their natural frequencies and mode shapes are presented.To demonstrate the validity of the method in this paper,the simulation results by ABAQUS are also given.On this basis,the detailed parametric analyses on the frequencies and dynamic responses of the three-level FGM stepped beam are carried out.The results show the accuracy and efficiency of the TMM.