5,442 research outputs found

    The relationships between shop floor management and QCCs to support Kaizen

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    Purpose - The purpose of this study is to develop and redefine the ‘classic’ roles of shop floor management and Quality Control Cycles (QCCs) in Kaizen. In specific, it aims to examine the linkage between shop floor management and QCCs, and test the relationships among shop floor management, QCCs and long-term Kaizen improvement outcomes. Design/methodology/approach – This study employs qualitative method by using a questionnaire to obtain data from 371 respondents in nine Sino-Japanese automotive joint-ventures. The data are analysed with the method of canonical correlation approach. Findings – The study identifies important factors to assist the adoption of shop floor management and QCCs for Kaizen. The analysis on the survey indicates that not all the shop floor management tools could help to identify improvement opportunities. QCCs are effective in addressing large problems and challenging current policies in companies, however, they have low impacts on individual learning. Research limitations/implications – The data of this study comes from nine Sino- Japanese automotive joint ventures. Therefore, the sample selection is limited in these companies. The findings are able to be applied for improving the similar problems which identified in this study. Practical implications – The study has the following practical implications, include the first one which is small shop floor problems can be identified and rapid solved continuously at source by shop floor management. The second one is QCCs, or other similar group-based improvement approaches take long to be fully addressed and implemented. Thirdly, practical solutions can be achieved from small and gradual changes, and they can prevent the results backsliding to the pre-improvement stage. Finally, QCCs are hardly to achieve a better improvement alone. It requires other Kaizen approaches to support. Originality/value – This study is probably the first to explore and investigate the implementation of the four building block tools of shop floor management in real business practise, and more specific the first to discuss the relationship among shop floor management, QCCs and long-term improvement outcomes based on empirical data from Sino-Japanese automotive joint-ventures

    Lutein Protects against Methotrexate-Induced and Reactive Oxygen Species-Mediated Apoptotic Cell Injury of IEC-6 Cells

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    Purpose High-dose chemotherapy using methotrexate (MTX) frequently induces side effects such as mucositis that leads to intestinal damage and diarrhea. Several natural compounds have been demonstrated of their effectiveness in protecting intestinal epithelial cells from these adverse effects. In this paper, we investigated the protection mechanism of lutein against MTX-induced damage in IEC-6 cells originating from the rat jejunum crypt. Methods: The cell viability, induced-apoptosis, reactive oxygen species (ROS) generation, and mitochondrial membrane potential in IEC-6 cells under MTX treatment were examined in the presence or absence of lutein. Expression level of Bcl2, Bad and ROS scavenging enzymes (including SOD, catalase and Prdx1) were detected by quantitative RT-PCR. Results: The cell viability of IEC-6 cells exposed to MTX was decreased in a dose- and time-dependent manner. MTX induces mitochondrial membrane potential loss, ROS generation and caspase 3 activation in IEC-6 cells. The cytotoxicity of MTX was reduced in IEC-6 cells by the 24 h pre-treatment of lutein. We found that pre-treatment of lutein significantly reduces MTX-induced ROS and apoptosis. The expression of SOD was up-regulated by the pre-treatment of lutein in the MTX-treated IEC-6 cells. These results indicated that lutein can protect IEC-6 cells from the chemo-drugs induced damage through increasing ROS scavenging ability. Conclusion: The MTX-induced apoptosis of IEC-6 cells was shown to be repressed by the pre-treatment of lutein, which may represent a promising adjunct to conventional chemotherapy for preventing intestinal damages

    Inhibitory Effects of Resveratrol on PDGF-BB-Induced Retinal Pigment Epithelial Cell Migration via PDGFRβ, PI3K/Akt and MAPK Pathways

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    Purpose: In diseases such as proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy, and age-related macular degeneration, retinal pigment epithelial (RPE) cells proliferate and migrate. Moreover, platelet-derived growth factor (PDGF) has been shown to enhance proliferation and migration of RPE cells in PVR. Even resveratrol can suppress the migration and adhesion of many cell types, its effects on RPE cell migration and adhesion remain unknown. In this study, we investigated the inhibitory effects of resveratrol on RPE cell migration induced by PDGF-BB, an isoform of PDGF, and adhesion to fibronectin, a major ECM component of PVR tissue. Methods: The migration of RPE cells was assessed by an electric cell-substrate impedance sensing migration assay and a Transwell migration assay. A cell viability assay was used to determine the viability of resveratrol treated-cells. The cell adhesion to fibronectin was examined by an adhesion assay. The interactions of resveratrol with PDGF-BB were analyzed by a dot binding assay. The PDGF-BB-induced signaling pathways were determined by western blotting and scratch wound healing assay. Results: Resveratrol inhibited PDGF-BB-induced RPE cell migration in a dose-dependent manner, but showed no effects on ARPE19 cell adhesion to fibronectin. The cell viability assay showed no cytotoxicity of resveratrol on RPE cells and the dot binding assay revealed no direct interactions of resveratrol with PDGF-BB. Inhibitory effects of resveratrol on PDGF-BB-induced platelet-derived growth factor receptor β (PDGFRβ) and tyrosine phosphorylation and the underlying pathways of PI3K/Akt, ERK and p38 activation were found; however, resveratrol and PDGF-BB showed no effects on PDGFRα and JNK activation. Scratch wound healing assay demonstrated resveratrol and the specific inhibitors of PDGFR, PI3K, MEK or p38 suppressed PDGF-BB-induced cell migration. Conclusions: These results indicate that resveratrol is an effective inhibitor of PDGF-BB-induced RPE cell migration via PDGFRβ, PI3K/Akt and MAPK pathways, but has no effects on the RPE cell adhesion to fibronectin

    Molecular cloning and characterization of a thioredoxin from Taiwanofungus camphorata

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    Abstract Background Thioredoxin (Trx) is reduced by thioredoxin reductase. Trx is used in ribonucleoide reduction, assimilatory sulfate reduction, in modulation of protein sulfhydryl groups, and refolding proteins. Results A TcTrx (Tc: Taiwanofungus camphorata) cDNA (640 bp, GenBank AY838902.1) encoding a putative thioredoxin (Trx) of 135 amino acid residues with calculated molecular mass of 16.17 kDa was cloned from Taiwanofungus c amphorata. The deduced amino acid sequence containing a motif (Cys-Gly-Pro-Cys) that is highly conserved among the reported Trxs. A three dimensional structural model of the TcTrx has been created based on the known structure of Malassezia sympodialis Trx (MsTrx, PDB ID: 2j23). To characterize the TcTrx, the codon optimized coding region was subcloned into an expression vector and transformed into Saccharomyces cerevisiae. The recombinant His8-tagged TcTrx was expressed and purified by Ni affinity chromatography. The purified enzyme showed a band of approximately 32 kDa (expected dimeric form) on a 12% SDS-PAGE. The molecular mass determined by MALDI-TOF is 33.16 kDa which suggests that the purified enzyme is a dimeric enzyme. Furthermore, the enzyme exhibited TcTrx activity via insulin assay. The Michaelis constant (K M ) value for insulin was 3.78 × 10−2 mM. The enzyme’s half-life of deactivation was 13 min at 45°C. The enzyme was most active at pH 7. Conclusions A three dimensional structural model of T. camphorata Trx based on its TcTrx cDNA sequence. The active form of the TcTrx has been successfully expressed in yeast. The enzyme possesses Trx activity and is capable of reduction of disulfide bonds during the formation of newly synthesized proteins. </jats:sec

    A Retrospective Cohort Study Comparing Stroke Recurrence Rate in Ischemic Stroke Patients With and Without Acupuncture Treatment.

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    Little was known about the effects of acupuncture on stroke recurrence. The aim of this study is to investigate whether ischemic stroke patients receiving acupuncture treatment have a decreased risk of stroke recurrence. A retrospective cohort study of 30,058 newly diagnosed cases of ischemic stroke in 2000 to 2004 was conducted based on the claims of Taiwan National Health Insurance Research Database. The use of acupuncture treatment and stroke recurrence were identified during the follow-up period from 2000 to 2009. This study compared the risk of stroke recurrence between ischemic stroke cohorts with and without acupuncture treatment by calculating adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of acupuncture associated with stroke recurrence in the Cox proportional hazard model. The stroke recurrence rate per 1000 person-years decreased from 71.4 without to 69.9 with acupuncture treatment (P &lt; 0.001). Acupuncture treatment was associated with reduced risk of stroke recurrence (HR 0.88; 95% CI 0.84-0.91). The acupuncture effect was noted in patients with or without medical treatment for stroke prevention but its impact decreased with aging of stroke patients. Compared with stroke patients without acupuncture treatment and medication therapy, the hazard ratios of stroke recurrence for those had medication therapy only, acupuncture only, and both were 0.42 (95% CI 0.38-0.46), 0.50 (95% CI 0.43-0.57), and 0.39 (95% CI 0.35-0.43), respectively. This study raises the possibility that acupuncture might be effective in lowering stroke recurrence rate even in those on medications for stroke prevention. Results suggest the need of prospective sham-controlled and randomized trials to establish the efficacy of acupuncture in preventing stroke

    翡翠水庫蓄水範圍保護帶設置對水庫水質改善影響

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    翡翠水庫係為大臺北地區民生用水重要來源,其污染來源以非點源污染為主。保護帶設置為非點源污染最佳管理作業 (BMP),也是目前翡翠水庫管理策略之一。本研究應用地理資訊系統 (GIS) 以及暴雨管理模式 (SWMM),模擬保護帶 (Buffer Strips) 設置後對翡翠水庫集水區非點源污染削減量,模擬水質項目包含懸浮固體 (SS)、總磷 (TP) 及生化需氧量 (BOD)。研究結果顯示,在蓄水範圍四周設置50 公尺保護帶時,設置保護帶的子集水區SS 輸出削減率超過80%,TP 削減率超過50%,BOD 削減率達到70%。另外利用Vollenweider 模式模擬保護帶設置對水庫水質影響,此總磷削減率最高可達6.1%。若以水庫總磷濃度10μg/L為目標值,則集水區總磷污染量尚需削減19.0%~22.2%。設置50 公尺保護帶可削減總磷每年約800 公斤,佔目標削減量1/3~1/4。除了設置保護帶外,尚需透過其他非點源污染控制措施才能達到此削減量。The Feitsui reservoir is the drinking water source for the Taipei metropolis, and nonpoint source pollution in this reservoir has been considered as an important issue. Buffer Strips are one of the best management practices (BMPs) and are used in Feitsui reservoir management. In this study, we integrate geographic information systems (GIS) and Stormwater Management Model (SWMM) to assess the effects of buffer strips in Feitsui reservoir. The major water quality items contain suspended solids (SS), total phosphorus (TP) and biochemical oxygen demand (BOD). The results show placing buffer strips 50 m in width around the reservoir can reduce 80% of SS, 50% of TP, and 70% of COD for the subwatersheds with buffer strips. In addition, the Vollenweider model is utilized to assess water quality in the reservoir and the results show that a 19-22% pollution reduction rate is required to achieve the goal of 10μg/L of TP. Buffer strips 50m in width contributed 1/3-1/4 reduction loads, which is 800 kgTP/yr. In addition to buffer strips, more BMPs are necessary in the watershed management of Feitsui reservoir

    WMAP constraint on the P-term inflationary model

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    In light of WMAP results, we examine the observational constraint on the P-term inflation. With the tunable parameter ff, P-term inflation contains richer physics than D-term and F-term inflationary models. We find the logarithmic derivative spectral index with n>1n>1 on large scales and n<1n<1 on small scales in agreement to observation. We obtained a reasonable range for the choice of the gauge coupling constant gg in order to meet the requirements of WMAP observation and the expected number of the e-foldings. Although tuning ff and gg we can have larger values for the logarithmic derivative of the spectral index, it is not possible to satisfy all observational requirements for both, the spectral index and its logarithmic derivative at the same time.Comment: 6 pages, double column, 13 figures included. Version appearing in the Physical Review
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