The graded density impactor(GDI)dynamic loading technique is crucial for acquiring the dynamic physical property parameters of materials used in weapons.The accuracy and timeliness of GDI structural design are key to ...The graded density impactor(GDI)dynamic loading technique is crucial for acquiring the dynamic physical property parameters of materials used in weapons.The accuracy and timeliness of GDI structural design are key to achieving controllable stress-strain rate loading.In this study,we have,for the first time,combined one-dimensional fluid computational software with machine learning methods.We first elucidated the mechanisms by which GDI structures control stress and strain rates.Subsequently,we constructed a machine learning model to create a structure-property response surface.The results show that altering the loading velocity and interlayer thickness has a pronounced regulatory effect on stress and strain rates.In contrast,the impedance distribution index and target thickness have less significant effects on stress regulation,although there is a matching relationship between target thickness and interlayer thickness.Compared with traditional design methods,the machine learning approach offers a10^(4)—10^(5)times increase in efficiency and the potential to achieve a global optimum,holding promise for guiding the design of GDI.展开更多
The utilization of graded Al powders offers the possibility to adjust the combustion performance of Al powders,while simultaneously safeguarding their energy properties.In this paper,a series of graded Al powder have ...The utilization of graded Al powders offers the possibility to adjust the combustion performance of Al powders,while simultaneously safeguarding their energy properties.In this paper,a series of graded Al powder have been incorporated into the typical Al@AP composites through the spray drying technique.The thermal behavior,ignition and combustion characteristics were comprehensively evaluated and compared.The experimental results showed that with the varying inclusion of the graded Al,the heat of reaction exhibited a significant change,ranging from 9090 J·g^(-1) to 11036 J·g^(-1),which was strongly dependent on the particle size of Al.The combination of Al with diverse range of particle sizes in graded configuration serves to significantly enhance the decomposition of AP,resulting in the disappearance of the LTD stage and a conspicuous decrease of at least 11.7℃ in the peak temperature of the HTD.Furthermore,the maximum burning rate achieved by the Al-3@AP composite was 33.6 mm·s^(-1),which was exactly twice as high as that of the graded Al-1@AP composite with the lowest burning rate.Diffraction peaks corresponding to unburned Al were detected in the condensed combustion products of Al-1@AP,and the combustion images clearly indicated an incomplete combustion tendency for this sample.In contrast,a well-designed gradation of Al powders,such as a combination of fine Al powders with a particle size below 5μm,has proven to be the most conducive to enhancing the combustion efficiency of the composites.展开更多
Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis r...Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis remain significant challenges.This research aims to develop an effective computational method for analyzing the free vibration of functionally graded(FG)microplates under high temperatures while resting on a Pasternak foundation(PF).This formulation leverages a new thirdorder shear deformation theory(new TSDT)for improved accuracy without requiring shear correction factors.Additionally,the modified couple stress theory(MCST)is incorporated to account for sizedependent effects in microplates.The PF is characterized by two parameters including spring stiffness(k_(w))and shear layer stiffness(k_(s)).To validate the proposed method,the results obtained are compared with those of the existing literature.Furthermore,numerical examples explore the influence of various factors on the high-temperature free vibration of FG microplates.These factors include the length scale parameter(l),geometric dimensions,material properties,and the presence of the elastic foundation.The findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the results of this research will have great potential in military and defense applications such as components of submarines,fighter aircraft,and missiles.展开更多
In this paper,the isogeometric analysis(IGA)method is employed to analyze the oscillation characteristics of functionally graded triply periodic minimal surface(FG-TPMS)curved-doubly shells integrated with magneto-ele...In this paper,the isogeometric analysis(IGA)method is employed to analyze the oscillation characteristics of functionally graded triply periodic minimal surface(FG-TPMS)curved-doubly shells integrated with magneto-electric surface layers(referred to as"FG-TPMS-MEE curved-doubly shells")subjected to low-velocity impact loads.This study presents low-velocity impact load model based on a single springmass(S-M)approach.The FG-TPMS-MEE curved-doubly shells are covered with two magneto-electric surface layers,while the core layer consists of three types:I-graph and Wrapped Package-graph(IWP),Gyroid(G),and Primitive(P),with various graded functions.These types are notable for their exceptional stiffness-to-weight ratios,enabling a wide range of potential applications.The Maxwell equations and electromagnetic boundary conditions are applied to compute the change in electric potentials and magnetic potentials.The equilibrium equations of the shell are derived from a refined higher-order shear deformation theory(HSDT),and the transient responses of the FG-TPMS-MEE curveddoubly shells are subsequently determined using Newmark's direct integration method.These results have applications in structural vibration control and the analysis of structures subjected to impact or explosive loads.Furthermore,this study provides a theoretical prediction of the low-velocity impact load and magneto-electric-elastic effects on the free vibration and transient response of FG-TPMS-MEE curved-doubly shells.展开更多
通过文献检索和筛选,选取了43个校园欺凌的干预研究,使用CMA3.0分析干预效果及影响因素,并使用GRADE系统对所有结局指标的证据质量进行评估。结果显示,针对欺凌者的干预项目具有中等效果量(g=0.57, p <0.05);针对欺凌受害者的干预项...通过文献检索和筛选,选取了43个校园欺凌的干预研究,使用CMA3.0分析干预效果及影响因素,并使用GRADE系统对所有结局指标的证据质量进行评估。结果显示,针对欺凌者的干预项目具有中等效果量(g=0.57, p <0.05);针对欺凌受害者的干预项目使得受害者的受欺凌行为减少(g=0.42, p <0.05),心理健康得到改善(g=0.40, p <0.01);针对所有学生的欺凌干预项目对其欺凌行为的效果g=0.17 (p <0.001),对其受欺凌行为效果g=0.19 (p <0.001),可能存在出版偏差;学生态度改变的效果g=0.40 (p <0.01)。除了态度改变的证据质量为中等,其他结局指标的证据都为低或者极低质量。对于所有学生干预项目,干预周期小于1学期的效果量大于干预周期大于1学期的效果量,教育干预项目效果量小于系统干预效果量,非随机研究效果量大于随机对照研究。直接针对欺凌者或者欺凌受害者的干预效果量中等,但是样本量少,需要进一步的研究证据支持。针对所有学生的欺凌干预项目虽然效果量低,但是仍具有实践意义,其效果量受到干预周期和干预特征的影响。展开更多
Determining the hydrometallurgical cut-off grades specifies the destination of low grade materials and this is subjected to more benefits in mining. Copper production rate is considered as one of the fundamental issue...Determining the hydrometallurgical cut-off grades specifies the destination of low grade materials and this is subjected to more benefits in mining. Copper production rate is considered as one of the fundamental issues in hydrometallurgical cut-off grades determination. Slags are remarked as one of the main sources of copper. It is not only regarded as a waste but also identified as another resource extracting base metals. Slags are characterized by copper high grade. Thus, slag copper recovery can be led to different cut-off grades and net present value(NPV). The current research scrutinizes the effect of slag recovery by both flotation and hydrometallurgical methods on the hydrometallurgical cut-off grades. For this purpose, the optimum cut-off grade algorithms of hydrometallurgical methods are developed by considering associated environmental parameters, incomes and also the costs. Then, their optimum amounts are calculated with NPV maximization as an objective function. The results indicate that considering slag copper recovery in the hydrometallurgical cut-off grade algorithms reduces the environmental costs caused by slag dumping and leads to more NPV by 9%.展开更多
目的基于GRADE系统对茵栀黄口服液联合常规疗法治疗新生儿黄疸进行循证分析。方法依据PICOS原则确定临床问题,检索主要中英文数据库,收集茵栀黄口服液治疗新生儿黄疸的系统评价/Meta分析和最新的随机对照试验文献,筛选Meta分析中的原始...目的基于GRADE系统对茵栀黄口服液联合常规疗法治疗新生儿黄疸进行循证分析。方法依据PICOS原则确定临床问题,检索主要中英文数据库,收集茵栀黄口服液治疗新生儿黄疸的系统评价/Meta分析和最新的随机对照试验文献,筛选Meta分析中的原始文献并与补充的随机对照试验整合以得到最终目标文献。通过Rev Man 5. 3软件整理目标文献的数据,并导入GRADE系统中,GRADEprofiler软件对每个结局指标进行质量评价,最终得到相关证据概要表和证据总结表。结果共纳入8个随机对照试验,总体证据低质量。其中,3个涉及胆红素水平下降率(高质量),4个涉及胆红素水平(低质量)、3个涉及黄疸消退时间(极低质量),1个涉及未光疗发生率(高质量),6个涉及有效率(中等质量),5个涉及不良反应(低质量)。结论茵栀黄口服液联合常规疗法能显著提高胆红素水平下降率,降低胆红素水平,缩短黄疸持续时间,减少光疗发生率,提高有效率,而且不良反应轻微,可为中成药治疗新生儿黄疸指南的制定提供循证依据。展开更多
为系统评价黄芪注射液联合西医常规治疗慢阻肺稳定期患者的疗效及证据质量,对中国知网、维普数据库、万方数据知识服务平台、PubMed、Web of science、Embase数据库进行检索,检索时间范围设定为:各数据库建库至2021年12月21日。两位研...为系统评价黄芪注射液联合西医常规治疗慢阻肺稳定期患者的疗效及证据质量,对中国知网、维普数据库、万方数据知识服务平台、PubMed、Web of science、Embase数据库进行检索,检索时间范围设定为:各数据库建库至2021年12月21日。两位研究员一组,分别独立检索、筛选文献,对纳入文献用Cochrane的偏倚风险评估工具评估,RevMan5.4软件和Sta-ta15.0软件进行统计和Meta分析,并按照GRADE标准对证据质量进行质量评价。共纳入15项研究,包括1236例病例。Meta分析结果显示:与对照组相比,黄芪注射液联合西医常规治疗能降低急性加重次数,提高临床有效率,改善肺功能,降低mMRC评分,降低IL-8和TNF-α水平。可见黄芪注射液联合西医常规治疗对稳定期慢阻肺患者提高生活质量、运动能力和降低炎症水平上优势明显,但值得注意的是本次研究的证据质量级别低,需要更多更高质量的研究来提升证据级别,临床医生做临床决策时还需谨慎。展开更多
目的系统评价针灸治疗紧张性头痛(tension-type headache,TTH)的临床疗效及纳入证据质量,为临床决策提供循证依据。方法通过检索中国知网(CNKI)、万方(Wanfang)、维普(VIP)、PubMed、Web of Science等数据库查找针灸治疗TTH的随机对照...目的系统评价针灸治疗紧张性头痛(tension-type headache,TTH)的临床疗效及纳入证据质量,为临床决策提供循证依据。方法通过检索中国知网(CNKI)、万方(Wanfang)、维普(VIP)、PubMed、Web of Science等数据库查找针灸治疗TTH的随机对照试验相关文献,检索时间从数据库建库至2021年11月25日。运用Cochrane偏倚风险评估工具对纳入研究进行偏倚风险分析,采用Review Manager 5.3软件对纳入研究的总有效率、头痛程度视觉模拟量表(VAS)评分、头痛发作频次、头痛持续时间、头痛指数进行Meta分析。并参考GRADE标准对证据质量进行评价。结果共纳入14项随机对照试验(RCT),①Meta分析结果显示:针灸组(或针灸联合西药组)总有效率高于西药组,差异有统计学意义[OR=1.22,95%CI(1.15,1.28),Z=7.17,P<0.00001];针灸组(或针灸联合西药组)在改善患者头痛程度[OR=-1.27,95%CI(-1.58,-0.96),Z=8.01,P<0.00001]、降低患者头痛发作频次[OR=-0.97,95%CI(-1.32,-0.62),Z=5.37,P<0.00001]、降低患者头痛持续时间[OR=-0.45,95%CI(-0.72,-0.17),Z=3.19,P=0.001]、降低头痛指数[OR=-8.78,95%CI(-10.32,-7.24),Z=6.06,P<0.00001]方面均优于西药组,且差异均有统计学意义。②GRADE结果显示:纳入证据质量在总有效率、头痛发作频次、头痛程度(VAS评分)、头痛持续时间方面为低级;头痛指数为极低级。结论针刺是治疗紧张型头痛的有效方法,在提高总有效率,降低患者头痛程度、持续时间及发作频次方面均优于西药组。但研究证据质量总体较低,在未来临床研究设计中应更加严谨规范,为针灸治疗TTH的临床疗效提供更可靠的证据。展开更多
为了系统评价参芪扶正注射液联合常规治疗作为干预措施对慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)患者的临床疗效和安全性。检索中国国家知识基础设施(China national knowledge infrastructure,CNKI)、PubMed、...为了系统评价参芪扶正注射液联合常规治疗作为干预措施对慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)患者的临床疗效和安全性。检索中国国家知识基础设施(China national knowledge infrastructure,CNKI)、PubMed、万方数据知识服务平台(Wanfang Data)、维普中文科技期刊数据库(Weipu China science and technology journal database,VIP)等数据库,筛选并纳入2023年6月18日以前发表的参芪扶正注射液联合常规疗法治疗COPD患者的随机对照试验(randomized controlled trials,RCT),采用Cochrane风险评价工具及评估、发展和评价建议分级(grading of recommendations assessment,development and evaluation,GRADE)系统进行文献证据质量评价,用RevMan 5.4软件对临床疗效及安全性指标进行Meta分析。结果表明,共纳入16项RCTs,1 486例患者。Meta分析结果显示,参芪扶正注射液辅助治疗可提高患者总有效率和第1秒用力呼气容积/用力肺活量比值(forced expiratory volume in one second/forced vital capacity,FEV1/FVC)指标,与对照组相比具有优势(P<0.000 01、P<0.000 1);不良反应少,无严重不良反应(adverse drug reactions,ADR),两组对比无统计学差异(P=0.32);GRADE评价结果显示,有效率及不良反应指标的证据质量均为中等级,肺功能为低等级。可见参芪扶正注射辅助治疗COPD可以提高患者临床疗效,改善肺功能,且具有良好的安全性。但所纳入研究具有局限性,证据质量不高,仍需结合中药辨证使用特点,规范实验方案,开展更多的高质量RCT研究。展开更多
Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter t...Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys,7075 aluminium alloy exhibits high strength which can be compared to that of steels and has profound applications in the designing of lightweight fortification structures and integrated protection systems. Having limitations such as poor bond integrity, formation of detrimental phases and interfacial reaction between reinforcement and substrate using fusion route to deposit hard particles paves the way to adopt friction stir processing for fabricating surface composites using different sizes of boron carbide particles as reinforcement on armour grade 7075 aluminium alloy as matrix in the present investigation. Wear and ballistic tests were carried out to assess the performance of friction stir processed AA7075 alloy. Significant improvement in wear resistance of friction stir processed surface composites is attributed to the change in wear mechanism from abrasion to adhesion. It has also been observed that the surface metal matrix composites have shown better ballistic resistance compared to the substrate AA7075 alloy. Addition of solid lubricant Mo S2 has reduced the depth of penetration of the projectile to half that of base metal AA7075 alloy. For the first time, the friction stir processing technique was successfully used to improve the wear and ballistic resistances of armour grade high strength AA7075 alloy.展开更多
The effect of ultraviolet mutagenesis on a heterotrophic strain(Providencia JAT-1) mutation was studied and bioleaching of low grade copper ore with mutant bacteria was investigated. The results show that the activity...The effect of ultraviolet mutagenesis on a heterotrophic strain(Providencia JAT-1) mutation was studied and bioleaching of low grade copper ore with mutant bacteria was investigated. The results show that the activity of bacteria was improved after ultraviolet mutagenesis; the best irradiation time was 120 s. Compared to the original bacteria, the cells density of mutant bacteria at stationary phase increased by 26% and ammonia produced by mutant bacteria increased by 12%. Higher activity of bacteria leads to a higher copper extraction rate. The bioleaching performance of Providencia JAT-1 was improved after UV mutagenesis. The copper extraction rate with mutant bacteria increased by 10.6% compared to the original bacteria. The ore surface was corroded and the fine particles were absent after bioleaching. Free copper oxide and copper silicates could be leached out easily by using JAT-1; a small part of the copper sulfide can also be leached out. Bioleaching using JAT-1 is more effective than ammonia leaching and copper extraction rate with mutant bacteria was 21.1% higher than that by ammonia leaching under the same condition.展开更多
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2021B0301030001)the National Key Research and Development Program of China(Grant No.2021YFB3802300)the Foundation of National Key Laboratory of Shock Wave and Detonation Physics(Grant No.JCKYS2022212004)。
文摘The graded density impactor(GDI)dynamic loading technique is crucial for acquiring the dynamic physical property parameters of materials used in weapons.The accuracy and timeliness of GDI structural design are key to achieving controllable stress-strain rate loading.In this study,we have,for the first time,combined one-dimensional fluid computational software with machine learning methods.We first elucidated the mechanisms by which GDI structures control stress and strain rates.Subsequently,we constructed a machine learning model to create a structure-property response surface.The results show that altering the loading velocity and interlayer thickness has a pronounced regulatory effect on stress and strain rates.In contrast,the impedance distribution index and target thickness have less significant effects on stress regulation,although there is a matching relationship between target thickness and interlayer thickness.Compared with traditional design methods,the machine learning approach offers a10^(4)—10^(5)times increase in efficiency and the potential to achieve a global optimum,holding promise for guiding the design of GDI.
文摘The utilization of graded Al powders offers the possibility to adjust the combustion performance of Al powders,while simultaneously safeguarding their energy properties.In this paper,a series of graded Al powder have been incorporated into the typical Al@AP composites through the spray drying technique.The thermal behavior,ignition and combustion characteristics were comprehensively evaluated and compared.The experimental results showed that with the varying inclusion of the graded Al,the heat of reaction exhibited a significant change,ranging from 9090 J·g^(-1) to 11036 J·g^(-1),which was strongly dependent on the particle size of Al.The combination of Al with diverse range of particle sizes in graded configuration serves to significantly enhance the decomposition of AP,resulting in the disappearance of the LTD stage and a conspicuous decrease of at least 11.7℃ in the peak temperature of the HTD.Furthermore,the maximum burning rate achieved by the Al-3@AP composite was 33.6 mm·s^(-1),which was exactly twice as high as that of the graded Al-1@AP composite with the lowest burning rate.Diffraction peaks corresponding to unburned Al were detected in the condensed combustion products of Al-1@AP,and the combustion images clearly indicated an incomplete combustion tendency for this sample.In contrast,a well-designed gradation of Al powders,such as a combination of fine Al powders with a particle size below 5μm,has proven to be the most conducive to enhancing the combustion efficiency of the composites.
文摘Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis remain significant challenges.This research aims to develop an effective computational method for analyzing the free vibration of functionally graded(FG)microplates under high temperatures while resting on a Pasternak foundation(PF).This formulation leverages a new thirdorder shear deformation theory(new TSDT)for improved accuracy without requiring shear correction factors.Additionally,the modified couple stress theory(MCST)is incorporated to account for sizedependent effects in microplates.The PF is characterized by two parameters including spring stiffness(k_(w))and shear layer stiffness(k_(s)).To validate the proposed method,the results obtained are compared with those of the existing literature.Furthermore,numerical examples explore the influence of various factors on the high-temperature free vibration of FG microplates.These factors include the length scale parameter(l),geometric dimensions,material properties,and the presence of the elastic foundation.The findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the results of this research will have great potential in military and defense applications such as components of submarines,fighter aircraft,and missiles.
文摘In this paper,the isogeometric analysis(IGA)method is employed to analyze the oscillation characteristics of functionally graded triply periodic minimal surface(FG-TPMS)curved-doubly shells integrated with magneto-electric surface layers(referred to as"FG-TPMS-MEE curved-doubly shells")subjected to low-velocity impact loads.This study presents low-velocity impact load model based on a single springmass(S-M)approach.The FG-TPMS-MEE curved-doubly shells are covered with two magneto-electric surface layers,while the core layer consists of three types:I-graph and Wrapped Package-graph(IWP),Gyroid(G),and Primitive(P),with various graded functions.These types are notable for their exceptional stiffness-to-weight ratios,enabling a wide range of potential applications.The Maxwell equations and electromagnetic boundary conditions are applied to compute the change in electric potentials and magnetic potentials.The equilibrium equations of the shell are derived from a refined higher-order shear deformation theory(HSDT),and the transient responses of the FG-TPMS-MEE curveddoubly shells are subsequently determined using Newmark's direct integration method.These results have applications in structural vibration control and the analysis of structures subjected to impact or explosive loads.Furthermore,this study provides a theoretical prediction of the low-velocity impact load and magneto-electric-elastic effects on the free vibration and transient response of FG-TPMS-MEE curved-doubly shells.
文摘通过文献检索和筛选,选取了43个校园欺凌的干预研究,使用CMA3.0分析干预效果及影响因素,并使用GRADE系统对所有结局指标的证据质量进行评估。结果显示,针对欺凌者的干预项目具有中等效果量(g=0.57, p <0.05);针对欺凌受害者的干预项目使得受害者的受欺凌行为减少(g=0.42, p <0.05),心理健康得到改善(g=0.40, p <0.01);针对所有学生的欺凌干预项目对其欺凌行为的效果g=0.17 (p <0.001),对其受欺凌行为效果g=0.19 (p <0.001),可能存在出版偏差;学生态度改变的效果g=0.40 (p <0.01)。除了态度改变的证据质量为中等,其他结局指标的证据都为低或者极低质量。对于所有学生干预项目,干预周期小于1学期的效果量大于干预周期大于1学期的效果量,教育干预项目效果量小于系统干预效果量,非随机研究效果量大于随机对照研究。直接针对欺凌者或者欺凌受害者的干预效果量中等,但是样本量少,需要进一步的研究证据支持。针对所有学生的欺凌干预项目虽然效果量低,但是仍具有实践意义,其效果量受到干预周期和干预特征的影响。
文摘Determining the hydrometallurgical cut-off grades specifies the destination of low grade materials and this is subjected to more benefits in mining. Copper production rate is considered as one of the fundamental issues in hydrometallurgical cut-off grades determination. Slags are remarked as one of the main sources of copper. It is not only regarded as a waste but also identified as another resource extracting base metals. Slags are characterized by copper high grade. Thus, slag copper recovery can be led to different cut-off grades and net present value(NPV). The current research scrutinizes the effect of slag recovery by both flotation and hydrometallurgical methods on the hydrometallurgical cut-off grades. For this purpose, the optimum cut-off grade algorithms of hydrometallurgical methods are developed by considering associated environmental parameters, incomes and also the costs. Then, their optimum amounts are calculated with NPV maximization as an objective function. The results indicate that considering slag copper recovery in the hydrometallurgical cut-off grade algorithms reduces the environmental costs caused by slag dumping and leads to more NPV by 9%.
文摘目的基于GRADE系统对茵栀黄口服液联合常规疗法治疗新生儿黄疸进行循证分析。方法依据PICOS原则确定临床问题,检索主要中英文数据库,收集茵栀黄口服液治疗新生儿黄疸的系统评价/Meta分析和最新的随机对照试验文献,筛选Meta分析中的原始文献并与补充的随机对照试验整合以得到最终目标文献。通过Rev Man 5. 3软件整理目标文献的数据,并导入GRADE系统中,GRADEprofiler软件对每个结局指标进行质量评价,最终得到相关证据概要表和证据总结表。结果共纳入8个随机对照试验,总体证据低质量。其中,3个涉及胆红素水平下降率(高质量),4个涉及胆红素水平(低质量)、3个涉及黄疸消退时间(极低质量),1个涉及未光疗发生率(高质量),6个涉及有效率(中等质量),5个涉及不良反应(低质量)。结论茵栀黄口服液联合常规疗法能显著提高胆红素水平下降率,降低胆红素水平,缩短黄疸持续时间,减少光疗发生率,提高有效率,而且不良反应轻微,可为中成药治疗新生儿黄疸指南的制定提供循证依据。
文摘为系统评价黄芪注射液联合西医常规治疗慢阻肺稳定期患者的疗效及证据质量,对中国知网、维普数据库、万方数据知识服务平台、PubMed、Web of science、Embase数据库进行检索,检索时间范围设定为:各数据库建库至2021年12月21日。两位研究员一组,分别独立检索、筛选文献,对纳入文献用Cochrane的偏倚风险评估工具评估,RevMan5.4软件和Sta-ta15.0软件进行统计和Meta分析,并按照GRADE标准对证据质量进行质量评价。共纳入15项研究,包括1236例病例。Meta分析结果显示:与对照组相比,黄芪注射液联合西医常规治疗能降低急性加重次数,提高临床有效率,改善肺功能,降低mMRC评分,降低IL-8和TNF-α水平。可见黄芪注射液联合西医常规治疗对稳定期慢阻肺患者提高生活质量、运动能力和降低炎症水平上优势明显,但值得注意的是本次研究的证据质量级别低,需要更多更高质量的研究来提升证据级别,临床医生做临床决策时还需谨慎。
文摘为了系统评价参芪扶正注射液联合常规治疗作为干预措施对慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)患者的临床疗效和安全性。检索中国国家知识基础设施(China national knowledge infrastructure,CNKI)、PubMed、万方数据知识服务平台(Wanfang Data)、维普中文科技期刊数据库(Weipu China science and technology journal database,VIP)等数据库,筛选并纳入2023年6月18日以前发表的参芪扶正注射液联合常规疗法治疗COPD患者的随机对照试验(randomized controlled trials,RCT),采用Cochrane风险评价工具及评估、发展和评价建议分级(grading of recommendations assessment,development and evaluation,GRADE)系统进行文献证据质量评价,用RevMan 5.4软件对临床疗效及安全性指标进行Meta分析。结果表明,共纳入16项RCTs,1 486例患者。Meta分析结果显示,参芪扶正注射液辅助治疗可提高患者总有效率和第1秒用力呼气容积/用力肺活量比值(forced expiratory volume in one second/forced vital capacity,FEV1/FVC)指标,与对照组相比具有优势(P<0.000 01、P<0.000 1);不良反应少,无严重不良反应(adverse drug reactions,ADR),两组对比无统计学差异(P=0.32);GRADE评价结果显示,有效率及不良反应指标的证据质量均为中等级,肺功能为低等级。可见参芪扶正注射辅助治疗COPD可以提高患者临床疗效,改善肺功能,且具有良好的安全性。但所纳入研究具有局限性,证据质量不高,仍需结合中药辨证使用特点,规范实验方案,开展更多的高质量RCT研究。
基金Financial assistance from Armament Research Board, New Delhi, India
文摘Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys,7075 aluminium alloy exhibits high strength which can be compared to that of steels and has profound applications in the designing of lightweight fortification structures and integrated protection systems. Having limitations such as poor bond integrity, formation of detrimental phases and interfacial reaction between reinforcement and substrate using fusion route to deposit hard particles paves the way to adopt friction stir processing for fabricating surface composites using different sizes of boron carbide particles as reinforcement on armour grade 7075 aluminium alloy as matrix in the present investigation. Wear and ballistic tests were carried out to assess the performance of friction stir processed AA7075 alloy. Significant improvement in wear resistance of friction stir processed surface composites is attributed to the change in wear mechanism from abrasion to adhesion. It has also been observed that the surface metal matrix composites have shown better ballistic resistance compared to the substrate AA7075 alloy. Addition of solid lubricant Mo S2 has reduced the depth of penetration of the projectile to half that of base metal AA7075 alloy. For the first time, the friction stir processing technique was successfully used to improve the wear and ballistic resistances of armour grade high strength AA7075 alloy.
基金Project(2012BAB08B02)supported by the National Key Technologies R&D Program for the 12th Five-year Plan,ChinaProjects(51304011,51374035)supported by the National Natural Science Foundation of China
文摘The effect of ultraviolet mutagenesis on a heterotrophic strain(Providencia JAT-1) mutation was studied and bioleaching of low grade copper ore with mutant bacteria was investigated. The results show that the activity of bacteria was improved after ultraviolet mutagenesis; the best irradiation time was 120 s. Compared to the original bacteria, the cells density of mutant bacteria at stationary phase increased by 26% and ammonia produced by mutant bacteria increased by 12%. Higher activity of bacteria leads to a higher copper extraction rate. The bioleaching performance of Providencia JAT-1 was improved after UV mutagenesis. The copper extraction rate with mutant bacteria increased by 10.6% compared to the original bacteria. The ore surface was corroded and the fine particles were absent after bioleaching. Free copper oxide and copper silicates could be leached out easily by using JAT-1; a small part of the copper sulfide can also be leached out. Bioleaching using JAT-1 is more effective than ammonia leaching and copper extraction rate with mutant bacteria was 21.1% higher than that by ammonia leaching under the same condition.
