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Mycophenolate mofetil or tacrolimus compared with azathioprine in long-term maintenance treatment for

《医学前沿(英文)》 2022年 第16卷 第5期   页码 799-807 doi: 10.1007/s11684-021-0849-2

摘要: This study aimed to evaluate the efficacy and safety of mycophenolate mofetil (MMF) or tacrolimus (TAC) compared with azathioprine (AZA) as maintenance therapy for active lupus nephritis (ALN). Patients with ALN who responded to 24 weeks of induction treatment were enrolled. Patients who received MMF or TAC as induction therapy continued MMF or TAC treatment during the maintenance period, whereas those who received intravenous cyclophosphamide were subjected to AZA treatment. The primary endpoint was the incidence of renal relapse. Secondary endpoints included extrarenal flares and composite endpoints (deaths, end-stage renal disease, or doubling of serum creatinine levels). A total of 123 ALN patients (47 in the MMF group, 37 in the TAC group, and 39 in the AZA group) were enrolled. The median follow-up time was 60 months. Ten MMF-treated patients, ten TAC-treated patients, and eight AZA-treated patients experienced renal relapses (P = 0.844). The cumulative renal relapse rates in the MMF group (P = 0.934) and TAC group (P = 0.673) were similar to the renal relapse rate in the AZA group. No significant difference in the incidence of severe adverse event was observed among the groups. Long-term maintenance therapies with MMF or TAC might have similarly low rates of renal relapse and similar safety profiles compared with AZA.

关键词: lupus nephritis     mycophenolate mofetil     tacrolimus     maintenance therapy    

Development and application of an off-site maintenance system in the petrochemical industry

Ruisheng YONG, Yanbing YE, Hanbin LUO, Lieyun DING

《工程管理前沿(英文)》 2017年 第4卷 第2期   页码 111-126 doi: 10.15302/J-FEM-2017027

摘要: On-site maintenance (ONSM) is critical to ensuring the safety of equipment in the petrochemical industry. However, many accidents occur during ONSM processes because of unstable equipment, complicated work environment, and human error. To reduce congestion and exposure to hazards during on-site operations and thereby reduce the probability of accidents, off-site maintenance (OFSM) is proposed based on Energy Release Theory (ERT). The information requirements for OFSM are analyzed. A support system for OFSM, which makes use of visualization, information management, and localization capabilities, is developed. A case study utilizing OFSM and its support system for an oil-loading facility of a petrochemical company is conducted. The application results indicated that implementation of OFSM system can significantly reduce the operation risks and can improve the operation efficiency.

关键词: on-site maintenance     petrochemical industry     safety     off-site maintenance system    

Risk evaluation for the task transfer of an aircraft maintenance program based on a multielement connection

《工程管理前沿(英文)》 doi: 10.1007/s42524-023-0282-0

摘要: This paper proposes a framework for evaluating the efficacy and suitability of maintenance programs with a focus on quantitative risk assessment in the domain of aircraft maintenance task transfer. The analysis is anchored in the principles of Maintenance Steering Group-3 (MSG-3) logic decision paradigms. The paper advances a holistic risk assessment index architecture tailored for the task transfer of maintenance programs. Utilizing the analytic network process (ANP), the study quantifies the weight interrelationships among diverse variables, incorporating expert-elicited subjective weighting. A multielement connection number-based evaluative model is employed to characterize decision-specific data, thereby facilitating the quantification of task transfer-associated risk through the appraisal of set-pair potentials. Moreover, the paper conducts a temporal risk trend analysis founded on partial connection numbers of varying orders. This analytical construct serves to streamline the process of risk assessment pertinent to maintenance program task transfer. The empirical component of this research, exemplified through a case study of the Boeing 737NG aircraft maintenance program, corroborates the methodological robustness and pragmatic applicability of the proposed framework in the quantification and analysis of mission transfer risk.

关键词: risk evaluation     maintenance steering group     analytic network process     task transfer     maintenance program    

Human reliability in maintenance task

Pacaiova HANA,

《机械工程前沿(英文)》 2010年 第5卷 第2期   页码 184-188 doi: 10.1007/s11465-010-0002-4

摘要: Maintenance management requirements have another dimension in the present as in the past. Looking for the optimal tools of decision processing is hard. The current concepts have represented the integration of theoretical, technical, and management tools whose applications need actual modification. Technical measurements are expensive and take a long time/term, and it is hard to estimate the economical returns. This paper presents the concept of a maintenance management task and its function in preventing major accidents. The importance of considering the reliability of maintenance tasks and the method to reach it are also discussed in this paper.

关键词: maintenance     risk assessment     failure     reliability     prevention    

民航视情维修决策优化模型发展

张海军,左洪福,梁剑,戎翔

《中国工程科学》 2005年 第7卷 第11期   页码 17-20

摘要:

目前视情维修是民航业采用的主要维修方式,可以使维修的有效性、经济性大幅度提高。维修决策优化模型对民航维修成本的降低和利润的提升具有显著的指导作用;归纳了视情维修的时间延迟模型、冲击模型、比例危险模型、马尔可夫决策模型等优化模型的建模方法;分析了该类模型在应用中存在的不足,并展望了其发展前景。

关键词: 视情维修     优化模型     决策     成本    

A review of condition-based maintenance: Its prognostic and operational aspects

Yanrong LI, Shizhe PENG, Yanting LI, Wei JIANG

《工程管理前沿(英文)》 2020年 第7卷 第3期   页码 323-334 doi: 10.1007/s42524-020-0121-5

摘要: Condition-based maintenance (CBM) detects early signs of failure and dictates when maintenance should be performed based on the actual condition of a system. In this paper, we first review some of the recent research on CBM under various physical structures and signal data. Then, we summarize several kinds of prognostic models that use monitoring information to estimate the reliability of complex systems or products. Monitoring information also facilitates operational decisions in production planning, spare parts management, reliability improvement, and prognostics and health management. Finally, we suggest some research opportunities for the reliability and operations management communities to fill the research gap between these two fields.

关键词: condition-based maintenance     prognostics     operational decision-making     reliability    

Trend prediction technology of condition maintenance for large water injection units

Xiaoli XU, Sanpeng DENG

《机械工程前沿(英文)》 2010年 第5卷 第2期   页码 171-175 doi: 10.1007/s11465-009-0091-0

摘要: Trend prediction technology is the key technology to achieve condition-based maintenance of mechanical equipment. Large-sized water injection units are key equipment in oilfields. The traditional preventive maintenance is not economical and cannot completely avoid vicious accidents. To ensure the normal operation of units and save maintenance costs, trend prediction technology is studied to achieve condition-based maintenance for water injection units. The main methods of the technology are given, the trend prediction method based on neural network is put forward, and the expert system based on the knowledge is developed. The industrial site verification shows that the proposed trend prediction technology can reflect the operating condition trend change of the water injection units and provide technical means to achieve condition-based predictive maintenance.

关键词: water injection units     condition-based maintenance     trend prediction    

规划维修及其在舰船装备维修保障中的应用

张文俊,王 苇,徐 巍,王 辉

《中国工程科学》 2015年 第17卷 第5期   页码 38-43

摘要:

为解决舰船装备普遍存在的维修技术资料深度不够,以及预防性维修大纲与保障资源配置无依据的问题,通过借鉴国内外相似装备成功经验,提出了舰船装备规划维修流程与技术要求,给出了实施管理措施,并结合某型号工程实际进行了验证。

关键词: 规划维修;预防性维修大纲;保障资源需求    

How to judge the association of postmenopausal hormone therapy and the risk of breast cancer

Ling XU

《医学前沿(英文)》 2010年 第4卷 第3期   页码 290-293 doi: 10.1007/s11684-010-0093-7

摘要: The relevance of postmenopausal hormone therapy (HT) for breast cancer risk has been long debated, although it is one of the most important barriers for women to accept HT. Various opinions have been reported from recent randomized clinical trials and epidemiological studies. These unanswered questions include: whether HT has a positive impact on breast cancer; whether risks of therapy with unopposed estrogen and combined estrogen-progestin are different; and whether different types and routes of estrogen and progestogens, as well as the duration and cessation of HT use, have different impacts on this disorder. Recently, there has been some good news such as the following: the currently available data do not provide sufficient evidence to prove a causal relationship between postmenopausal HT and breast cancer; breast cancer in postmenopausal women using HT usually has better prognosis than that of nonusers. In conclusion, HT is still the most effective method of relieving climacteric symptoms for many postmenopausal women. However, a possible risk of breast cancer associated with long-term HT usage should not be ignored. With respect to prevention of breast cancer, regular evaluation of individual breast cancer susceptibility and close follow-up through mammography and/or breast sonography are necessary strategies for the safety of HT use.

关键词: breast cancer     postmenopausal hormone therapy     unopposed estrogen therapy     combined estrogen-progestin therapy    

kinetostatic modeling and morphology characterization of cable-driven continuum robots for aero-engine maintenance

《机械工程前沿(英文)》 2023年 第18卷 第3期 doi: 10.1007/s11465-023-0756-0

摘要: In-situ maintenance is of great significance for improving the efficiency and ensuring the safety of aero-engines. The cable-driven continuum robot (CDCR) with twin-pivot compliant mechanisms, which is enabled with flexible deformation capability and confined space accessibility, has emerged as a novel tool that aims to promote the development of intelligence and efficiency for in-situ aero-engine maintenance. The high-fidelity model that describes the kinematic and morphology of CDCR lays the foundation for the accurate operation and control for in-situ maintenance. However, this model was not well addressed in previous literature. In this study, a general kinetostatic modeling and morphology characterization methodology that comprehensively contains the effects of cable-hole friction, gravity, and payloads is proposed for the CDCR with twin-pivot compliant mechanisms. First, a novel cable-hole friction model with the variable friction coefficient and adaptive friction direction criterion is proposed through structure optimization and kinematic parameter analysis. Second, the cable-hole friction, all-component gravities, deflection-induced center-of-gravity shift of compliant joints, and payloads are all considered to deduce a comprehensive kinetostatic model enabled with the capacity of accurate morphology characterization for CDCR. Finally, a compact continuum robot system is integrated to experimentally validate the proposed kinetostatic model and the concept of in-situ aero-engine maintenance. Results indicate that the proposed model precisely predicts the morphology of CDCR and outperforms conventional models. The compact continuum robot system could be considered a novel solution to perform in-situ maintenance tasks of aero-engines in an invasive manner.

关键词: kinetostatic modeling     morphology characterization     variable friction     continuum robots     in-situ maintenance    

Particle therapy for cancers: a new weapon in radiation therapy

null

《医学前沿(英文)》 2012年 第6卷 第2期   页码 165-172 doi: 10.1007/s11684-012-0196-4

摘要:

Particle irradiation started to draw attention in the past decade and has now become a hotspot in the radiation oncology community. This article reviews the most advanced developments in particle irradiation, focusing on the characteristics of proton and carbon ions in radiation physics and radiobiology. The Bragg peak of physical dose distribution causes proton and carbon beams to optimally meet the requirement for cancer irradiation because the Bragg peak permits the accurate concentration of the dose on the tumor, thus sparing the adjacent normal tissues. Moreover, carbon ion has more radiobiological benefits than photon and proton beams. These benefits include stronger sterilization effects on intrinsic radio-resistant tumors and more effective killing of hypoxic, G0, and S phase cells. Compared with the most advanced radiation techniques using photon, such as three-dimensional conformal radiation therapy and intensity-modulated radiation therapy, proton therapy has yielded more promising outcomes in local control and survival for head and neck cancers, prostate carcinoma, and pediatric cancers. Carbon therapy in Japan showed even more promising results than proton therapy. The local controls and overall survivals were as good as that treated by surgery in early stages of non-small cell lung cancer, hepatocellular carcinoma, prostate carcinoma, and head and neck cancers, especially for such highly resistant tumors as melanoma. The non-invasive nature of particle therapy affords more patients with chances to receive and benefit from treatment. Particle therapy is gradually getting attention from the oncology community. However, the cost of particle therapy facilities has limited the worldwide use of this technology.

关键词: radiation therapy     particle therapy     proton     carbon     cancer    

Effect of cutterhead configuration on tunnel face stability during shield machine maintenance outages

《结构与土木工程前沿(英文)》 2023年 第17卷 第4期   页码 522-532 doi: 10.1007/s11709-023-0930-9

摘要: Owing to long-distance advancement or obstacles, shield tunneling machines are typically shut down for maintenance. Engineering safety during maintenance outages is determined by the stability of the tunnel face. Pressure maintenance openings are typically used under complicated hydrogeological conditions. The tunnel face is supported by a medium at the bottom of the excavation chamber and compressed air at the top. Owing to the high risk of face failure, the necessity of support pressure when cutterhead support is implemented and a method for determining the value of compressed air pressure using different support ratios must to be determined. In this study, a non-fully chamber supported rotational failure model considering cutterhead support is developed based on the upper-bound theorem of limit analysis. Numerical simulation is conducted to verify the accuracy of the proposed model. The results indicate that appropriately increasing the specific gravity of the supporting medium can reduce the risk of collapse. The required compressed air pressure increases significantly as the support ratio decreases. Disregarding the supporting effect of the cutterhead will result in a tunnel face with underestimated stability. To satisfy the requirement of chamber openings at atmospheric pressure, the stratum reinforcement strength and range at the shield end are provided based on different cutterhead aperture ratios.

关键词: tunnel face stability     cutterhead configuration     aperture ratio     pressure gradient     support ratio    

Experimental study on the establishment and maintenance of brain death model with pigs

ZHANG Shuijun, SHI Jihua, ZHAI Wenlong, SONG Yan, CHEN Shi

《医学前沿(英文)》 2007年 第1卷 第2期   页码 161-166 doi: 10.1007/s11684-007-0030-6

摘要: It remains controversial that after the transplantation of using grafts from brain-dead donors, organs injury and rejection can influence the effects of transplantation. This study sought to explore methods of establishing a stable brain death (BD) model using Bama mini pigs and to maintain the brain-dead state for a comparatively long period to provide a model for investigating changes in brain death. Sixteen anesthetized Bama mini pigs were randomized into a control group ( = 5) and a BD group ( = 11). Intracranial pressure (ICP) was increased in a modified, slow, and intermittent way to establish BD. Respiration and circulation were sustained during the brain-dead state. Hemodynamic changes were monitored during the experiment. In the BD group, 10 pigs met the requirements for brain death and 1 died of cardiopulmonary complications following an increase in ICP. Brain death was maintained for more than 48 hours with artificial life support. During the experiment, the heart rate and blood pressure showed characteristic changes due to increased ICP. Prior to BD being established, a tic reaction inevitably occurred. We used an improved method of increasing ICP to establish a stable BD model. The BD state could be maintained for more than 48 hours with effective respiratory and circulatory support. Disappearance of the tic reaction was considered to be one of the verified indexes for BD via encephalic pressure increase.

关键词: BD     control     Hemodynamic     cardiopulmonary     modified    

Study and practice on condition-based maintenance of induced fans in coal-fired power plants

CHEN Gang, LI Bing, CHEN Fei, HUANG Shuhong

《能源前沿(英文)》 2008年 第2卷 第2期   页码 211-215 doi: 10.1007/s11708-008-0028-z

摘要: Reducing the enormous maintenance cost is essential to enhance the competitiveness for power plants. An overall design scheme for condition-based maintenance of induced fans is proposed for large thermal power plants. The interface of the above framework is simple and convenient; the optimum maintenance strategy is given by condition monitoring and risk evaluating. The decision-supported system was used in Guangdong Shajiao C Power Plant. The results show that it is a feasible maintenance optimization scheme for power plants.

Passive antibody therapy in emerging infectious diseases

《医学前沿(英文)》 doi: 10.1007/s11684-023-1021-y

摘要: The epidemic of corona virus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 and its variants of concern (VOCs) has been ongoing for over 3 years. Antibody therapies encompassing convalescent plasma, hyperimmunoglobulin, and neutralizing monoclonal antibodies (mAbs) applied in passive immunotherapy have yielded positive outcomes and played a crucial role in the early COVID-19 treatment. In this review, the development path, action mechanism, clinical research results, challenges, and safety profile associated with the use of COVID-19 convalescent plasma, hyperimmunoglobulin, and mAbs were summarized. In addition, the prospects of applying antibody therapy against VOCs was assessed, offering insights into the coping strategies for facing new infectious disease outbreaks.

关键词: SARS-CoV-2     COVID-19     convalescent plasma     hyperimmunoglobulin     neutralizing monoclonal antibodies    

标题 作者 时间 类型 操作

Mycophenolate mofetil or tacrolimus compared with azathioprine in long-term maintenance treatment for

期刊论文

Development and application of an off-site maintenance system in the petrochemical industry

Ruisheng YONG, Yanbing YE, Hanbin LUO, Lieyun DING

期刊论文

Risk evaluation for the task transfer of an aircraft maintenance program based on a multielement connection

期刊论文

Human reliability in maintenance task

Pacaiova HANA,

期刊论文

民航视情维修决策优化模型发展

张海军,左洪福,梁剑,戎翔

期刊论文

A review of condition-based maintenance: Its prognostic and operational aspects

Yanrong LI, Shizhe PENG, Yanting LI, Wei JIANG

期刊论文

Trend prediction technology of condition maintenance for large water injection units

Xiaoli XU, Sanpeng DENG

期刊论文

规划维修及其在舰船装备维修保障中的应用

张文俊,王 苇,徐 巍,王 辉

期刊论文

How to judge the association of postmenopausal hormone therapy and the risk of breast cancer

Ling XU

期刊论文

kinetostatic modeling and morphology characterization of cable-driven continuum robots for aero-engine maintenance

期刊论文

Particle therapy for cancers: a new weapon in radiation therapy

null

期刊论文

Effect of cutterhead configuration on tunnel face stability during shield machine maintenance outages

期刊论文

Experimental study on the establishment and maintenance of brain death model with pigs

ZHANG Shuijun, SHI Jihua, ZHAI Wenlong, SONG Yan, CHEN Shi

期刊论文

Study and practice on condition-based maintenance of induced fans in coal-fired power plants

CHEN Gang, LI Bing, CHEN Fei, HUANG Shuhong

期刊论文

Passive antibody therapy in emerging infectious diseases

期刊论文