860 resultados para chain saw
Resumo:
Direct evidence confirming the hypothesis that a dysfunction of the mitochondrial respiratory chain (MRC) underlies the pathogenesis of hyperlactatemia associated with highly active antiretroviral therapy (HAART) is scarce. We studied mitochondrial DNA (mtDNA) content and MRC function in the skeletal muscle of an HIV-infected patient during an episode of symptomatic hyperlactatemia. Skeletal muscle biopsy was performed during the episode when the patient was symptomatic and 3 months later when the patient was clinically recovered. Assessment of mitochondria was performed using histological, polarographic, spectrophotometrical, and Southern blot and real time PCR DNA quantification methods. The histological study disclosed extensive mitochondrial impairment in the form of ragged-red fibers or equivalents on oxidative reactions. These findings were associated with an increase in mitochondrial content and a decrease in both mitochondrial respiratory capacity and MRC enzyme activities. Mitochondrial DNA content declined to 53% of control values. Mitochondrial abnormalities had almost disappeared later when the patient became asymptomatic. Our findings support the hypothesis that MRC dysfunction stands at the basis of HAART-related hyperlactatemia.
Resumo:
Direct evidence confirming the hypothesis that a dysfunction of the mitochondrial respiratory chain (MRC) underlies the pathogenesis of hyperlactatemia associated with highly active antiretroviral therapy (HAART) is scarce. We studied mitochondrial DNA (mtDNA) content and MRC function in the skeletal muscle of an HIV-infected patient during an episode of symptomatic hyperlactatemia. Skeletal muscle biopsy was performed during the episode when the patient was symptomatic and 3 months later when the patient was clinically recovered. Assessment of mitochondria was performed using histological, polarographic, spectrophotometrical, and Southern blot and real time PCR DNA quantification methods. The histological study disclosed extensive mitochondrial impairment in the form of ragged-red fibers or equivalents on oxidative reactions. These findings were associated with an increase in mitochondrial content and a decrease in both mitochondrial respiratory capacity and MRC enzyme activities. Mitochondrial DNA content declined to 53% of control values. Mitochondrial abnormalities had almost disappeared later when the patient became asymptomatic. Our findings support the hypothesis that MRC dysfunction stands at the basis of HAART-related hyperlactatemia.
Resumo:
Bacterial programmed cell death and quorum sensing are direct examples of prokaryote group behaviors, wherein cells coordinate their actions to function cooperatively like one organism for the benefit of the whole culture. We demonstrate here that 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO), a Pseudomonas aeruginosa quorum-sensing-regulated low-molecular-weight excreted molecule, triggers autolysis by self-perturbing the electron transfer reactions of the cytochrome bc1 complex. HQNO induces specific self-poisoning by disrupting the flow of electrons through the respiratory chain at the cytochrome bc1 complex, causing a leak of reducing equivalents to O2 whereby electrons that would normally be passed to cytochrome c are donated directly to O2. The subsequent mass production of reactive oxygen species (ROS) reduces membrane potential and disrupts membrane integrity, causing bacterial cell autolysis and DNA release. DNA subsequently promotes biofilm formation and increases antibiotic tolerance to beta-lactams, suggesting that HQNO-dependent cell autolysis is advantageous to the bacterial populations. These data identify both a new programmed cell death system and a novel role for HQNO as a critical inducer of biofilm formation and antibiotic tolerance. This newly identified pathway suggests intriguing mechanistic similarities with the initial mitochondrial-mediated steps of eukaryotic apoptosis.
Resumo:
Background: The DNA repair protein O6-Methylguanine-DNA methyltransferase (MGMT) confers resistance to alkylating agents. Several methods have been applied to its analysis, with methylation-specific polymerase chain reaction (MSP) the most commonly used for promoter methylation study, while immunohistochemistry (IHC) has become the most frequently used for the detection of MGMT protein expression. Agreement on the best and most reliable technique for evaluating MGMT status remains unsettled. The aim of this study was to perform a systematic review and meta-analysis of the correlation between IHC and MSP. Methods A computer-aided search of MEDLINE (1950-October 2009), EBSCO (1966-October 2009) and EMBASE (1974-October 2009) was performed for relevant publications. Studies meeting inclusion criteria were those comparing MGMT protein expression by IHC with MGMT promoter methylation by MSP in the same cohort of patients. Methodological quality was assessed by using the QUADAS and STARD instruments. Previously published guidelines were followed for meta-analysis performance. Results Of 254 studies identified as eligible for full-text review, 52 (20.5%) met the inclusion criteria. The review showed that results of MGMT protein expression by IHC are not in close agreement with those obtained with MSP. Moreover, type of tumour (primary brain tumour vs others) was an independent covariate of accuracy estimates in the meta-regression analysis beyond the cut-off value. Conclusions Protein expression assessed by IHC alone fails to reflect the promoter methylation status of MGMT. Thus, in attempts at clinical diagnosis the two methods seem to select different groups of patients and should not be used interchangeably.
Resumo:
Hemoglobin and its structures have been described since the 1990s to enhance a variety of biological activities of endotoxins (LPS) in a dose-dependent manner. To investigate the interaction processes in more detail, the system was extended by studying the interactions of newly designed peptides from the γ-chain of human hemoglobin with the adjuvant monophosphoryl lipid A (MPLA), a partial structure of lipid A lacking its 1-phosphate. It was found that some selected Hbg peptides, in particular two synthetic substructures designated Hbg32 and Hbg35, considerably increased the bioactivity of MPLA, which alone was only a weak activator of immune cells. These findings hold true for human mononuclar cells, monocytes and T lymphocytes. To understand the mechanisms of action in more detail, biophysical techniques were applied. These showed a peptide-induced change of the MPLA aggregate structure from multilamellar into a non-lamellar, probably inverted, cubic structure. Concomitantly, the peptides incorporated into the tightly packed MPLA aggregates into smaller units down to monomers. The fragmentation of the aggregates was an endothermic process, differing from a complex formation but rather typical for a catalytic reaction.
Resumo:
Value chain collaboration has been a prevailing topic for research, and there is a constantly growing interest in developing collaborative models for improved efficiency in logistics. One area of collaboration is demand information management, which enables improved visibility and decrease of inventories in the value chain. Outsourcing of non-core competencies has changed the nature of collaboration from intra-enterprise to cross-enterprise activity, and this together with increasing competition in the globalizing markets have created a need for methods and tools for collaborative work. The retailer part in the value chain of consumer packaged goods (CPG) has been studied relatively widely, proven models have been defined, and there exist several best practice collaboration cases. The information and communications technology has developed rapidly, offering efficient solutions and applications to exchange information between value chain partners. However, the majority of CPG industry still works with traditional business models and practices. This concerns especially companies operating in the upstream of the CPG value chain. Demand information for consumer packaged goods originates at retailers' counters, based on consumers' buying decisions. As this information does not get transferred along the value chain towards the upstream parties, each player needs to optimize their part, causing safety margins for inventories and speculation in purchasing decisions. The safety margins increase with each player, resulting in a phenomenon known as the bullwhip effect. The further the company is from the original demand information source, the more distorted the information is. This thesis concentrates on the upstream parts of the value chain of consumer packaged goods, and more precisely the packaging value chain. Packaging is becoming a part of the product with informative and interactive features, and therefore is not just a cost item needed to protect the product. The upstream part of the CPG value chain is distinctive, as the product changes after each involved party, and therefore the original demand information from the retailers cannot be utilized as such – even if it were transferred seamlessly. The objective of this thesis is to examine the main drivers for collaboration, and barriers causing the moderate adaptation level of collaborative models. Another objective is to define a collaborative demand information management model and test it in a pilot business situation in order to see if the barriers can be eliminated. The empirical part of this thesis contains three parts, all related to the research objective, but involving different target groups, viewpoints and research approaches. The study shows evidence that the main barriers for collaboration are very similar to the barriers in the lower part of the same value chain; lack of trust, lack of business case and lack of senior management commitment. Eliminating one of them – the lack of business case – is not enough to eliminate the two other barriers, as the operational model in this thesis shows. The uncertainty of the future, fear of losing an independent position in purchasing decision making and lack of commitment remain strong enough barriers to prevent the implementation of the proposed collaborative business model. The study proposes a new way of defining the value chain processes: it divides the contracting and planning process into two processes, one managing the commercial parts and the other managing the quantity and specification related issues. This model can reduce the resistance to collaboration, as the commercial part of the contracting process would remain the same as in the traditional model. The quantity/specification-related issues would be managed by the parties with the best capabilities and resources, as well as access to the original demand information. The parties in between would be involved in the planning process as well, as their impact for the next party upstream is significant. The study also highlights the future challenges for companies operating in the CPG value chain. The markets are becoming global, with toughening competition. Also, the technology development will most likely continue with a speed exceeding the adaptation capabilities of the industry. Value chains are also becoming increasingly dynamic, which means shorter and more agile business relationships, and at the same time the predictability of consumer demand is getting more difficult due to shorter product life cycles and trends. These changes will certainly have an effect on companies' operational models, but it is very difficult to estimate when and how the proven methods will gain wide enough adaptation to become standards.
Resumo:
This study focuses to the intersection of three sets of activities in a company: expert work, development work and supply chain management, SCM. Experts and expert work represent a set of individuals whose efficiency and impact this study is intended to improve, while development work defines the set of organizational activities to focus on. SCM as an expertise area acts as the platform on which this study is built. The study has two aims. Firstly, it aims to derive a model helping an SCM expert to increase the effectiveness of expert work in development tasks by understanding the encountered organizational situations and processes better, reflecting his/her past and future actions to organizational processes and selecting and adjusting the processes and contents of his/her work accordingly. Secondly, it aims to develop applicable approaches and methods to understand, evaluate and manage the organizational processes and situations in development work. The integrative model on approaches and methods to improve the effectiveness of development processes is split to two aggregate dimensions: technical performance of the developed solution and consumption of resources of the development process. Six potential approaches and methods aiming at helping in the management of organizational dimensions are presented in enclosed publications. The approaches focus on three subtasks of development work: decision making, implementation and change, and knowledge accumulation. The approaches and methods have been tested in case studies representing typical development processes in the area of supply chain management. As a result, four suggestions are presented. Firstly, SCM experts are advised to consider the SCM development work to be consisting of development processes. Secondly, inside these processes they should identify and evaluate the risk of difficult decision-making related to organizational factors. Thirdly, they are prompted for an active role in implementation and change, supporting the implementation through whole process. Finally, the development should be seen in a holistic view, taking into account the stage of knowledge and organizational issues related to it, and adopt a knowledge development strategy.
Resumo:
The usual objectives that companies have for subcontracting are studied in this thesis. The case company’s objectives for contract manufacturing now and in the future are identified. The main objective of the thesis is to create a focused model for the structure and supply chain management in the contract manufacturing network. This model is made for case company’s certain profit center. The different possibilities and their advantages and disadvantages for the structure and supply chain management are examined trough a theoretical review of literature. The possibilities found are then examined from the case company’s point of view. The case company point of view is established based on the opinions of the case company’s representatives. The outcome of the thesis is that the star shaped structure with supply chain management centralized to case company would be the best choice for the case company to manage the contract manufacture network.
Resumo:
Mimicry is a central plank of the emotional contagion theory; however, it was only tested with facial and postural emotional stimuli. This study explores the existence of mimicry in voice-to-voice communication by analyzing 8,747 sequences of emotional displays between customers and employees in a call-center context. We listened live to 967 telephone inter-actions, registered the sequences of emotional displays, and analyzed them with a Markov chain. We also explored other propositions of emotional contagion theory that were yet to be tested in vocal contexts. Results supported that mimicry is significantly present at all levels. Our findings fill an important gap in the emotional contagion theory; have practical implications regarding voice-to-voice interactions; and open doors for future vocal mimicry research.
Resumo:
Succeeding in small board lot (0-20 tons) deliveries, is not always prosperous and failures as well as extra costs compared to standard costs arise. Failure deliveries from converting plants to customer locations tie a lot of unwanted and unexpected costs. Extra costs are handled as quality costs and more precise, internal failure costs. These costs revolve from unsuccessful truck payloads, redundant warehousing or unfavorable routing as examples. Quality costs are becoming more and more important factor in company’s financial decision making. Actual, realized truck payload correlates with the extra costs occurring, so filling the truck payload all get-out well is a key to lower the extra costs. Case company in this study is Corporation A, business segment Boards. Boards have outsourced half of their converting in order to gain better customer service via flexibility, lead time reductions and logistics efficiency improvements. Examination period of the study is first two quarters of year 2008 and deliveries examined are from converters to the customer locations. In Corporation A’s case, the total loss in failure deliveries is hundreds of thousands of Euros during the examination period. So, the logistics goal of getting the right product to the right place and right time for the least cost, does not completely realize.
Resumo:
The aim of this thesis is to analyze how increasing the level of unitizing affects to the costs in the transport system of a Finnish paper and board company. The parts of the supply chain where costs are analyzed are limited to domestic inland transport and port operations. Supply Chain management is important aspect of modern day companies’ strategies. Intermodal transport and different transport systems are the key items which are studied in the theory part of this thesis. In the case study the payload simulations for SECU container (Stora Enso Cargo Unit) stuffed in mills sites are base of the cost analyze of this thesis. Thesis also makes a glance for the restrictions and development trends in Finnish railroads. In analyze SECU containers are moved up to the mill site for stuffing. This increases the level of unitizing in supply chain. Analyze is made for three variation of current traffic lines. Analyze shows that when idea of intermodalism is well used there is considerable cost savings to gather in pre-transportation and port operations. But also effects to mill sites and destination ports needs to be take under considering. In analyze the effects of increased axle weight for SECU container transportation in Finnish railroads is studied. When transport unit is stuffed in earliest possible point supply chain and unloaded the last possible point the savings made in chain can be considerable. In case study of this thesis almost 40% savings in total costs could be reached in pre transportation and port operations when unitizing level is increased in supply chain.
Resumo:
Leaf scald of barley caused by Rhynchosporium secalis is an important disease in Argentina. The fungus is a necrotrophic pathogen which survives in stubble, seeds and weeds. Isolation of R. secalis from seeds on artificial media usually has not been successful due to the slow growth rate of the pathogen and strong inhibition by contaminants. The objective in this work was to detect R. secalis in different genotypes of barley seeds in Argentina using the polymerase chain reaction (PCR)-based diagnostic assay. Four barley genotypes were tested in 2004: Quilmes Ayelén, Quilmes Alfa, Barke and Maltería Pampa 1004. The previously described RS8 and RS9 primers were used for the detection of R. secalis in barley seeds. A 264-bp single band was obtained for each cultivar showing the presence of R. secalis. The use of specific primers was efficient in the detection of R. secalis in barley seeds in Argentina and could be used for routine diagnosis, epidemiology and seed transmission studies. This is the first report on the detection of R. secalis in barley seeds in Argentina.