The reignition of aero-engine combustors at high altitudes poses significant challenges due to the low-temperature and low-pressure environment.A novel Long Pulse-Width Plasma Ignition(LPWPI)system has been developed ...The reignition of aero-engine combustors at high altitudes poses significant challenges due to the low-temperature and low-pressure environment.A novel Long Pulse-Width Plasma Ignition(LPWPI)system has been developed to enhance ignition performance.The LPWPI system can effectively prolong the discharge duration time,improve ignition efficacy,and increase the plasma penetration depth.Experimental comparisons with the traditional Spark Ignition(SI)system demonstrate that the LPWPI increased discharge duration to 2.03 ms,which is 45 times longer than that of the SI system,while also doubling the spark penetration depth to 24.1 mm.The LPWPI system achieved a discharge efficiency of 61.1%,significantly surpassing the SI system's efficiency of23.3%.These advancements facilitated an extension of the lean ignition boundary by approximately 22.7%to 39.3%.High-speed camera recordings reveal that the spark duration of the LPWPI system was extended to 2.1 ms,compared to 0.6 ms in the SI system.Ignition progress with LPWPI shows a sustained spark kernel without the flame residence stage observed in the SI system.The impressive performance of the LPWPI system suggests that it is a promising alternative for aero-engine ignition systems.展开更多
BACKGROUND Epigenetic regulation of leptin(LEP)plays a critical role in metabolic disorders,yet its promoter methylation patterns in lean diabetic populations remain poorly characterized.Emerging evidence suggests DNA...BACKGROUND Epigenetic regulation of leptin(LEP)plays a critical role in metabolic disorders,yet its promoter methylation patterns in lean diabetic populations remain poorly characterized.Emerging evidence suggests DNA methylation may precede clinical hyperglycemia,offering potential for early risk stratification.While obesity-associated LEP methylation is well-studied,lean Asian populations who exhibit high diabetes prevalence despite lower adiposity,represent an underexplored cohort.This study hypothesizes that LEP promoter methylation in peripheral leukocytes decreases progressively from normoglycemia to prediabetes and type 2 diabetes mellitus(T2DM),correlating inversely with serum LEP levels in lean Chinese adults[body mass index(BMI)<24 kg/m^(2)].AIM To investigate LEP promoter methylation status and its association with serum LEP levels across glycemic states in lean Chinese adults.METHODS We enrolled 392 participants including 120 normoglycemic controls,94 prediabetes[44 impaired fasting glucose(IFG)/50 impaired glucose tolerance(IGT)],178 T2DM aged 40-60 years with BMI<24 kg/m^(2).Genomic DNA from peripheral leukocytes underwent bisulfite conversion followed by methylation-specific PCR to assess CpG methylation in the LEP promoter.Serum LEP was quantified via enzyme-linked immunosorbent assay,with other parameters measured through standard assays.Statistical analyses included analysis of variance,χ²tests,and Pearson correlation(Bonferroni-corrected P value).RESULTS Methylation frequencies declined progressively:59.2%(controls)reduced to 43.6%(prediabetes;IFG:38.6%,IGT:48%)reduced to 31.5%(T2DM)(all P<0.05 vs controls;T2DM vs IGT:P=0.030).Serum LEP levels increased significantly in T2DM(16.94±4.19μg/L)vs controls(11.33±3.10μg/L;P=0.002),with intermediate values in prediabetes(IFG:13.79±3.32μg/L;IGT:12.62±4.81μg/L).A near-perfect inverse correlation between methylation and LEP levels was observed(r=-0.95,95%CI:-0.97 to-0.92,P<0.001),persisting after adjusting for age and BMI(β=-0.91,P<0.001).CONCLUSION LEP promoter hypomethylation parallels worsening glycemic status in lean Chinese adults,suggesting its potential as a blood-based epigenetic biomarker for diabetes progression,pending validation in longitudinal cohorts.展开更多
Over the past few years,the Cu element has attracted much attention in duplex stainless steels.It undoubtedly holds advantageous in regulating the two-phase proportion and austenite stability and is also one of the cr...Over the past few years,the Cu element has attracted much attention in duplex stainless steels.It undoubtedly holds advantageous in regulating the two-phase proportion and austenite stability and is also one of the crucial factors affecting the corrosion resistance.However,the systematic research on the impact of Cu addition to lean duplex stainless steels remains insufficient.In this study,a novel Cu-alloyed Mn-N-type 20Cr lean duplex stainless steel was developed and the effect of Cu on the strain hardening capacity and corrosion resistance was analyzed.The results show that the Cu addition increases the volume fraction and stability of the austenite,retards the martensitic transformation,and extends the transformation-induced plasticity effect to a wider strain range.Compared to the Cu-free steel,the plasticity of Cu-containing steel can be increased by~26%.Additionally,the addition of Cu redistributes the Cr and N elements in the ferrite and austenite phases,thereby improving the corrosion resistance of the lean duplex stainless steel.展开更多
Objective:To evaluate the application value of lean management in the management of flexible endoscopes.Methods:From January to December 2023,routine management was implemented,and 200 flexible endoscopes used for exa...Objective:To evaluate the application value of lean management in the management of flexible endoscopes.Methods:From January to December 2023,routine management was implemented,and 200 flexible endoscopes used for examination and treatment were included in the control group;from January to December 2024,lean management was implemented,and 200 flexible endoscopes used for examination and treatment were included in the observation group.The average daily usage frequency,management effectiveness,and failure rate of flexible endoscopes were compared between the two groups.Results:The average daily usage frequency of flexible endoscopes in the observation group was higher than that in the control group(P<0.05);the 3S retrieval rate and spot-check qualification rate of endoscopes in the observation group were higher than those in the control group(P<0.05);the failure rate of flexible endoscopes in the observation group was lower than that in the control group(P<0.05).Conclusion:Implementing lean management during the management of flexible endoscopes can improve the efficiency of endoscope retrieval,increase the average daily usage frequency of flexible endoscopes,and reduce endoscope failures.展开更多
This study systematically investigated the Lean Blowoff(LBO)limits of Two-Dimensional(2D)bluff-body stabilized premixed flames by varying the air mass flow rate,inflowtemperature,bluff-body width,and fuel type.The dat...This study systematically investigated the Lean Blowoff(LBO)limits of Two-Dimensional(2D)bluff-body stabilized premixed flames by varying the air mass flow rate,inflowtemperature,bluff-body width,and fuel type.The data of LBO limits were analyzed and fittedaccording to the Damk?hler(Da)and Reynolds(Re)numbers,and the fitting accuracy of LBO datawas highly improved by a modified characteristic length simultaneously considering the length andwidth of the bluff body,which is usually neglected in the previous studies.Moreover,to our knowl-edge,this is the first time that simultaneous transverse and spanwise OH*-Chemiluminescence(CL)imaging has been performed to examine the three-dimensional behavior of the LBO process.The flame stability is heavily affected by the mass and energy transport between reactants andproducts in both directions,potentially leading to the flame pinch-off.The intensity and positionof the upstream flame after pinch-off are decisive to the occurrence of the following LBO.Whenthe upstream flame after pinch-off is weak and close to the bluff body,it cannot re-ignite thedownstream unburnt gas.Subsequently,a permanent downstream extinction occurs,and theLBO takes place.The results help understand the LBO mechanism of 2D bluff-body stabilizedflames.展开更多
Lean construction has been newly applied to construction industry. The best performance of a project can be achieved through the precise definition of construction product, rational work break structure, lean supply c...Lean construction has been newly applied to construction industry. The best performance of a project can be achieved through the precise definition of construction product, rational work break structure, lean supply chain, decrease of resources waste, objective control and so forth. Referring to the characteristics of schedule planning of construction projects and lean construction philosophy, we proposed optimizing methodology of real-time and dynamic schedule of construction projects based on lean construction. The basis of the methodology is process reorganization and lean supply in construction enterprises. The traditional estimating method of the activity duration is fuzzy and random;however, a newly proposed lean forecasting method employs multi-components linear-regression, back-propagation artificial neural networks and learning curve. Taking account of the limited resources and the fixed duration of a project, the optimizing method of the real-time and dynamic schedule adopts the concept of resource driving. To optimize the schedule of a construction project timely and effectively, an intellectualized schedule management system was developed. It can work out the initial schedule, optimize the real-time and dynamic schedule, and display the schedule with the Gant Chart, the net-work graph and the space-time line chart. A case study was also presented to explain the proposed method.展开更多
TiO2/γ-Al2O3 supported In/Ag catalysts were prepared by impregnation method,and investigated for NO reduction with CO as the reducing agent under lean burn conditions.The microscopic structure and surface properties ...TiO2/γ-Al2O3 supported In/Ag catalysts were prepared by impregnation method,and investigated for NO reduction with CO as the reducing agent under lean burn conditions.The microscopic structure and surface properties of the catalysts were studied by N2 adsorption-desorption,X-ray diffraction,transmission electron microscopy,X-ray photoelectron spectroscopy,ultraviolet-visible spectroscopy,H2 temperature-programmed reduction and Fourier transform infrared spectroscopy.TiO2/γ-Al2O3 supported In/Ag is a good catalyst for the reduction of NO to N2.It displayed high dispersion,large amounts of surface active components and high NO adsorption capacity,which gave good catalytic performance and stability for the reduction of NO with CO under lean burn conditions.The silver species stabilized and improved the dispersion of the indium species.The introduction of TiO2 into the γ-Al2O3 support promoted NO adsorption and improved the dispersion of the indium species and silver species.展开更多
The increase on the competitiveness, the search on the customer satisfaction, the search by reducing waste in the civil construction were facts which helped entrepreneurs and companies to seek new ways of working, bei...The increase on the competitiveness, the search on the customer satisfaction, the search by reducing waste in the civil construction were facts which helped entrepreneurs and companies to seek new ways of working, being lean construction one of the ways to get that. Studies report that the application of the lean tools in construction was carried out in an isolated way. This type of application was pointed as a major factor limiting the extent of achievement in implementing lean principles. The aim of this studies is to identify opportunities to implement the principles of lean production in the service department of a construction company in Goi^is, proposing routines that try to implement the continuous improvement of its processes, eliminating waste, reducing the lead time, allow it to perform the mapping processes, applying the just-in-time and among others, providing services that add value to the customer satisfaction. It was possible to establish the average time for each step, allowing to identify possible improvements in the department, from the perspective of lean principles. The research paper concludes by pointing out the activities for the Department of Post Construction work from building companies, from lean concepts.展开更多
There are frequent failures in the project delivery in time and increasing the waste in Oman construction industry.Lean Construction(LC)principles which are lean thinking in design and construction process may be a po...There are frequent failures in the project delivery in time and increasing the waste in Oman construction industry.Lean Construction(LC)principles which are lean thinking in design and construction process may be a possible solution.Hence,the paper is aimed on exploring the status of the LC practices and its impact on Omani Construction Industry(OCI).The paper presents barriers,potential benefits,and the measures of suitability and acceptability of LC principles.A quantitative research approach was adopted and research data was collected using an online questionnaire survey in Oman.The data were analysed and results are presented in tables and charts followed by critical discussions.The survey found that onethird of the construction professionals have a good awareness and half of them having a higher level awareness about LC practices.More than one third of the construction organisations are adopting LC principles with a high consensus on the suitability and acceptability,and they recognised that time commitment is necessary for the successful implementation and achieve benefits.The study concludes that the reduction in project delivery time and construction at site waste is the key advantage of implementing LC priciples in design and construction stages in the omani construction industry.展开更多
In contemporary contexts,Lean Six Sigma(LSS)is extensively utilized and has evolved across various sectors due to its substantial benefits.This paper aims to explore the definition,origin,and development of LSS,as wel...In contemporary contexts,Lean Six Sigma(LSS)is extensively utilized and has evolved across various sectors due to its substantial benefits.This paper aims to explore the definition,origin,and development of LSS,as well as its key tools,methods,theoretical research,and future prospects.Furthermore,it analyzes the theoretical foundations and practical applications of LSS in-depth,with an emphasis on anticipating future development trends.The goal is to provide readers with a comprehensive overview of LSS and offer insights for enterprises seeking to implement LSS for process improvement and innovation.展开更多
BACKGROUND Nonalcoholic fatty liver disease(NAFLD)is one of the most common chronic diseases in the world.Nowadays,the percentage of non-obese or lean patients with NAFLD is increasing.NAFLD in non-obese populations,e...BACKGROUND Nonalcoholic fatty liver disease(NAFLD)is one of the most common chronic diseases in the world.Nowadays,the percentage of non-obese or lean patients with NAFLD is increasing.NAFLD in non-obese populations,especially the lean subgroup with a normal waist circumference(WC),might lead to more problems than obese individuals,as these individuals may not visit clinics for NAFLD diagnosis or ignore the diagnosis of NAFLD.If the precise characteristics of these populations,especially the lean subgroup,are identified,the clinicians would be able to provide more appropriate advice and treatment to these populations.AIM To investigate the prevalence,clinical characteristics,risk factors,and possible indicators for NAFLD in lean Chinese adults with a normal WC.METHODS People without diabetes mellitus or significant alcohol consumption who underwent routine health examinations were included.Their fatty liver index(FLI),abdominal ultrasonography results,and controlled attenuation parameter were all assessed.Genotyping for single-nucleotide polymorphisms associated with NAFLD was performed in another small group consisting of biopsy-proven NAFLD subjects and healthy controls.RESULTS A total of 2715 subjects who underwent routine health examinations were included in the study.Among 810 lean participants with a normal WC,142(17.5%)fulfilled the diagnostic criteria for NAFLD.Waist-height ratio,hemoglobin,platelets,and triglycerides were significant factors associated with the presence of NAFLD in these participants.The appropriate cut-off value of the FLI score in screening for NAFLD in the lean subjects with a normal WC was 25.15,which had a 77.8%sensitivity and 75.9%specificity.There was no significant difference in the single-nucleotide polymorphisms in the SIRT1,APOC3,PNPLA3,AGTR1,and PPARGC1A genes between lean subjects with and without NAFLD(P<0.05).CONCLUSION NAFLD is not uncommon in lean Chinese adults even with a normal WC.Metabolic factors,rather than genetic factors,may play important roles in the development of NAFLD in this population.A lower cut-off value of the FLI score in screening for NAFLD should be used for lean Chinese adults with a normal WC.展开更多
Much has been published on the characteristics of type 2 diabetes mellitus and its association with the epidemic of obesity.But relatively little is known about the incidence of lean diabetes,progression of disease an...Much has been published on the characteristics of type 2 diabetes mellitus and its association with the epidemic of obesity.But relatively little is known about the incidence of lean diabetes,progression of disease and fate of the patients with low-normal body mass index(< 25).Studies in developing countries have shown that the clinical characteristics of these patients include history of childhood malnutrition,poor socioeconomic status,relatively early age of onset and absence of ketosis on withdrawal of insulin.In the United States,recent studies showed that the lean,normal weight diabetes is not rare especially among minority populations.They showed that these patients are mainly males,have higher prevalence of insulin use indicating rapid beta cell failure.They might have increased total,cardiovascular and non cardiovascular mortality when compared to obese diabetic patients.In this review,the epidemiologic and clinical features of lean diabetes are presented.The potential causal mechanisms of this emerging diabetes type that may include genetic,autoimmune,acquired and behavioral factors are discussed.The need for studies to further elucidate the causation as well as specific prevention and treatment of lean diabetes is emphasized.展开更多
基金co-supported by the National Natural Science Foundation of China(Nos.52376138 and 52025064)the Science Center for Gas Turbine Project,China(No.P2022B-Ⅱ-018-001)the Foundation Research Project,China(No.1002TJA22010)。
文摘The reignition of aero-engine combustors at high altitudes poses significant challenges due to the low-temperature and low-pressure environment.A novel Long Pulse-Width Plasma Ignition(LPWPI)system has been developed to enhance ignition performance.The LPWPI system can effectively prolong the discharge duration time,improve ignition efficacy,and increase the plasma penetration depth.Experimental comparisons with the traditional Spark Ignition(SI)system demonstrate that the LPWPI increased discharge duration to 2.03 ms,which is 45 times longer than that of the SI system,while also doubling the spark penetration depth to 24.1 mm.The LPWPI system achieved a discharge efficiency of 61.1%,significantly surpassing the SI system's efficiency of23.3%.These advancements facilitated an extension of the lean ignition boundary by approximately 22.7%to 39.3%.High-speed camera recordings reveal that the spark duration of the LPWPI system was extended to 2.1 ms,compared to 0.6 ms in the SI system.Ignition progress with LPWPI shows a sustained spark kernel without the flame residence stage observed in the SI system.The impressive performance of the LPWPI system suggests that it is a promising alternative for aero-engine ignition systems.
文摘BACKGROUND Epigenetic regulation of leptin(LEP)plays a critical role in metabolic disorders,yet its promoter methylation patterns in lean diabetic populations remain poorly characterized.Emerging evidence suggests DNA methylation may precede clinical hyperglycemia,offering potential for early risk stratification.While obesity-associated LEP methylation is well-studied,lean Asian populations who exhibit high diabetes prevalence despite lower adiposity,represent an underexplored cohort.This study hypothesizes that LEP promoter methylation in peripheral leukocytes decreases progressively from normoglycemia to prediabetes and type 2 diabetes mellitus(T2DM),correlating inversely with serum LEP levels in lean Chinese adults[body mass index(BMI)<24 kg/m^(2)].AIM To investigate LEP promoter methylation status and its association with serum LEP levels across glycemic states in lean Chinese adults.METHODS We enrolled 392 participants including 120 normoglycemic controls,94 prediabetes[44 impaired fasting glucose(IFG)/50 impaired glucose tolerance(IGT)],178 T2DM aged 40-60 years with BMI<24 kg/m^(2).Genomic DNA from peripheral leukocytes underwent bisulfite conversion followed by methylation-specific PCR to assess CpG methylation in the LEP promoter.Serum LEP was quantified via enzyme-linked immunosorbent assay,with other parameters measured through standard assays.Statistical analyses included analysis of variance,χ²tests,and Pearson correlation(Bonferroni-corrected P value).RESULTS Methylation frequencies declined progressively:59.2%(controls)reduced to 43.6%(prediabetes;IFG:38.6%,IGT:48%)reduced to 31.5%(T2DM)(all P<0.05 vs controls;T2DM vs IGT:P=0.030).Serum LEP levels increased significantly in T2DM(16.94±4.19μg/L)vs controls(11.33±3.10μg/L;P=0.002),with intermediate values in prediabetes(IFG:13.79±3.32μg/L;IGT:12.62±4.81μg/L).A near-perfect inverse correlation between methylation and LEP levels was observed(r=-0.95,95%CI:-0.97 to-0.92,P<0.001),persisting after adjusting for age and BMI(β=-0.91,P<0.001).CONCLUSION LEP promoter hypomethylation parallels worsening glycemic status in lean Chinese adults,suggesting its potential as a blood-based epigenetic biomarker for diabetes progression,pending validation in longitudinal cohorts.
基金supported by the Jilin Scientific and Technological Development Program(No.YDZJ202201ZYTS669)the National Natural Science Foundation of China(Nos.51974032,52174355,51874043 and 51604034).
文摘Over the past few years,the Cu element has attracted much attention in duplex stainless steels.It undoubtedly holds advantageous in regulating the two-phase proportion and austenite stability and is also one of the crucial factors affecting the corrosion resistance.However,the systematic research on the impact of Cu addition to lean duplex stainless steels remains insufficient.In this study,a novel Cu-alloyed Mn-N-type 20Cr lean duplex stainless steel was developed and the effect of Cu on the strain hardening capacity and corrosion resistance was analyzed.The results show that the Cu addition increases the volume fraction and stability of the austenite,retards the martensitic transformation,and extends the transformation-induced plasticity effect to a wider strain range.Compared to the Cu-free steel,the plasticity of Cu-containing steel can be increased by~26%.Additionally,the addition of Cu redistributes the Cr and N elements in the ferrite and austenite phases,thereby improving the corrosion resistance of the lean duplex stainless steel.
文摘Objective:To evaluate the application value of lean management in the management of flexible endoscopes.Methods:From January to December 2023,routine management was implemented,and 200 flexible endoscopes used for examination and treatment were included in the control group;from January to December 2024,lean management was implemented,and 200 flexible endoscopes used for examination and treatment were included in the observation group.The average daily usage frequency,management effectiveness,and failure rate of flexible endoscopes were compared between the two groups.Results:The average daily usage frequency of flexible endoscopes in the observation group was higher than that in the control group(P<0.05);the 3S retrieval rate and spot-check qualification rate of endoscopes in the observation group were higher than those in the control group(P<0.05);the failure rate of flexible endoscopes in the observation group was lower than that in the control group(P<0.05).Conclusion:Implementing lean management during the management of flexible endoscopes can improve the efficiency of endoscope retrieval,increase the average daily usage frequency of flexible endoscopes,and reduce endoscope failures.
基金the financial support of the National Natural Science Foundation of China(Nos.U2141221 and 52076136)the National Science and Technology Major Project,China(Nos.J2019-Ⅲ-0004-0047 and Y2022-Ⅲ-0001-0010)+1 种基金the Center for Basic Science of Aero Engines and Gas Turbines Project,China(No.P2022-B-Ⅱ019-001)the Natural Science Foundation of Shanghai,China(Nos.22ZR1467900 and 23ZR1481400)。
文摘This study systematically investigated the Lean Blowoff(LBO)limits of Two-Dimensional(2D)bluff-body stabilized premixed flames by varying the air mass flow rate,inflowtemperature,bluff-body width,and fuel type.The data of LBO limits were analyzed and fittedaccording to the Damk?hler(Da)and Reynolds(Re)numbers,and the fitting accuracy of LBO datawas highly improved by a modified characteristic length simultaneously considering the length andwidth of the bluff body,which is usually neglected in the previous studies.Moreover,to our knowl-edge,this is the first time that simultaneous transverse and spanwise OH*-Chemiluminescence(CL)imaging has been performed to examine the three-dimensional behavior of the LBO process.The flame stability is heavily affected by the mass and energy transport between reactants andproducts in both directions,potentially leading to the flame pinch-off.The intensity and positionof the upstream flame after pinch-off are decisive to the occurrence of the following LBO.Whenthe upstream flame after pinch-off is weak and close to the bluff body,it cannot re-ignite thedownstream unburnt gas.Subsequently,a permanent downstream extinction occurs,and theLBO takes place.The results help understand the LBO mechanism of 2D bluff-body stabilizedflames.
文摘Lean construction has been newly applied to construction industry. The best performance of a project can be achieved through the precise definition of construction product, rational work break structure, lean supply chain, decrease of resources waste, objective control and so forth. Referring to the characteristics of schedule planning of construction projects and lean construction philosophy, we proposed optimizing methodology of real-time and dynamic schedule of construction projects based on lean construction. The basis of the methodology is process reorganization and lean supply in construction enterprises. The traditional estimating method of the activity duration is fuzzy and random;however, a newly proposed lean forecasting method employs multi-components linear-regression, back-propagation artificial neural networks and learning curve. Taking account of the limited resources and the fixed duration of a project, the optimizing method of the real-time and dynamic schedule adopts the concept of resource driving. To optimize the schedule of a construction project timely and effectively, an intellectualized schedule management system was developed. It can work out the initial schedule, optimize the real-time and dynamic schedule, and display the schedule with the Gant Chart, the net-work graph and the space-time line chart. A case study was also presented to explain the proposed method.
基金supported by the National Science & Technology Pillar Program(2012BAF03B02)National Natural Science Foundation of China(21101085,U1162203)+3 种基金Natural Science Foundation of Liaoning Province(2015020196)Doctoral Fund of Shandong Province(BS2015HZ003)Fushun Science & Technology Program(FSKJHT 201423)Liaoning Excellent Talents Program in University(LJQ2012031)~~
文摘TiO2/γ-Al2O3 supported In/Ag catalysts were prepared by impregnation method,and investigated for NO reduction with CO as the reducing agent under lean burn conditions.The microscopic structure and surface properties of the catalysts were studied by N2 adsorption-desorption,X-ray diffraction,transmission electron microscopy,X-ray photoelectron spectroscopy,ultraviolet-visible spectroscopy,H2 temperature-programmed reduction and Fourier transform infrared spectroscopy.TiO2/γ-Al2O3 supported In/Ag is a good catalyst for the reduction of NO to N2.It displayed high dispersion,large amounts of surface active components and high NO adsorption capacity,which gave good catalytic performance and stability for the reduction of NO with CO under lean burn conditions.The silver species stabilized and improved the dispersion of the indium species.The introduction of TiO2 into the γ-Al2O3 support promoted NO adsorption and improved the dispersion of the indium species and silver species.
文摘The increase on the competitiveness, the search on the customer satisfaction, the search by reducing waste in the civil construction were facts which helped entrepreneurs and companies to seek new ways of working, being lean construction one of the ways to get that. Studies report that the application of the lean tools in construction was carried out in an isolated way. This type of application was pointed as a major factor limiting the extent of achievement in implementing lean principles. The aim of this studies is to identify opportunities to implement the principles of lean production in the service department of a construction company in Goi^is, proposing routines that try to implement the continuous improvement of its processes, eliminating waste, reducing the lead time, allow it to perform the mapping processes, applying the just-in-time and among others, providing services that add value to the customer satisfaction. It was possible to establish the average time for each step, allowing to identify possible improvements in the department, from the perspective of lean principles. The research paper concludes by pointing out the activities for the Department of Post Construction work from building companies, from lean concepts.
文摘There are frequent failures in the project delivery in time and increasing the waste in Oman construction industry.Lean Construction(LC)principles which are lean thinking in design and construction process may be a possible solution.Hence,the paper is aimed on exploring the status of the LC practices and its impact on Omani Construction Industry(OCI).The paper presents barriers,potential benefits,and the measures of suitability and acceptability of LC principles.A quantitative research approach was adopted and research data was collected using an online questionnaire survey in Oman.The data were analysed and results are presented in tables and charts followed by critical discussions.The survey found that onethird of the construction professionals have a good awareness and half of them having a higher level awareness about LC practices.More than one third of the construction organisations are adopting LC principles with a high consensus on the suitability and acceptability,and they recognised that time commitment is necessary for the successful implementation and achieve benefits.The study concludes that the reduction in project delivery time and construction at site waste is the key advantage of implementing LC priciples in design and construction stages in the omani construction industry.
文摘In contemporary contexts,Lean Six Sigma(LSS)is extensively utilized and has evolved across various sectors due to its substantial benefits.This paper aims to explore the definition,origin,and development of LSS,as well as its key tools,methods,theoretical research,and future prospects.Furthermore,it analyzes the theoretical foundations and practical applications of LSS in-depth,with an emphasis on anticipating future development trends.The goal is to provide readers with a comprehensive overview of LSS and offer insights for enterprises seeking to implement LSS for process improvement and innovation.
基金National Key R&D Program of China,No.2017YFC0908900National Natural Science Foundation of China,No.81873565 and No.81900507Hospital Funded Clinical Research,Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine,No.17CSK04 and No.15LC06.
文摘BACKGROUND Nonalcoholic fatty liver disease(NAFLD)is one of the most common chronic diseases in the world.Nowadays,the percentage of non-obese or lean patients with NAFLD is increasing.NAFLD in non-obese populations,especially the lean subgroup with a normal waist circumference(WC),might lead to more problems than obese individuals,as these individuals may not visit clinics for NAFLD diagnosis or ignore the diagnosis of NAFLD.If the precise characteristics of these populations,especially the lean subgroup,are identified,the clinicians would be able to provide more appropriate advice and treatment to these populations.AIM To investigate the prevalence,clinical characteristics,risk factors,and possible indicators for NAFLD in lean Chinese adults with a normal WC.METHODS People without diabetes mellitus or significant alcohol consumption who underwent routine health examinations were included.Their fatty liver index(FLI),abdominal ultrasonography results,and controlled attenuation parameter were all assessed.Genotyping for single-nucleotide polymorphisms associated with NAFLD was performed in another small group consisting of biopsy-proven NAFLD subjects and healthy controls.RESULTS A total of 2715 subjects who underwent routine health examinations were included in the study.Among 810 lean participants with a normal WC,142(17.5%)fulfilled the diagnostic criteria for NAFLD.Waist-height ratio,hemoglobin,platelets,and triglycerides were significant factors associated with the presence of NAFLD in these participants.The appropriate cut-off value of the FLI score in screening for NAFLD in the lean subjects with a normal WC was 25.15,which had a 77.8%sensitivity and 75.9%specificity.There was no significant difference in the single-nucleotide polymorphisms in the SIRT1,APOC3,PNPLA3,AGTR1,and PPARGC1A genes between lean subjects with and without NAFLD(P<0.05).CONCLUSION NAFLD is not uncommon in lean Chinese adults even with a normal WC.Metabolic factors,rather than genetic factors,may play important roles in the development of NAFLD in this population.A lower cut-off value of the FLI score in screening for NAFLD should be used for lean Chinese adults with a normal WC.
文摘Much has been published on the characteristics of type 2 diabetes mellitus and its association with the epidemic of obesity.But relatively little is known about the incidence of lean diabetes,progression of disease and fate of the patients with low-normal body mass index(< 25).Studies in developing countries have shown that the clinical characteristics of these patients include history of childhood malnutrition,poor socioeconomic status,relatively early age of onset and absence of ketosis on withdrawal of insulin.In the United States,recent studies showed that the lean,normal weight diabetes is not rare especially among minority populations.They showed that these patients are mainly males,have higher prevalence of insulin use indicating rapid beta cell failure.They might have increased total,cardiovascular and non cardiovascular mortality when compared to obese diabetic patients.In this review,the epidemiologic and clinical features of lean diabetes are presented.The potential causal mechanisms of this emerging diabetes type that may include genetic,autoimmune,acquired and behavioral factors are discussed.The need for studies to further elucidate the causation as well as specific prevention and treatment of lean diabetes is emphasized.
