901 resultados para Lean maintenance
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Introduction of potent antiretroviral combination therapy (ART) has reduced overall morbidity and mortality amongst HIV-infected adults. Some prophylactic regimes against opportunistic infections can be discontinued in patients under successful ART. (1) The influence of the availability of ART on incidence and mortality of disseminated M. avium Complex infection (MAC). (2) The safety of discontinuation of maintenance therapy against MAC in patients on ART. The Swiss HIV-Cohort Study, a prospective multicentre study of HIV-infected adults. Patients with a nadir CD4 count below 50 cells/mm3 were considered at risk for MAC and contributed to total follow-up time for calculating the incidence. Survival analysis was performed by using Kaplan Meier and Cox proportional hazards methods. Safety of discontinuation of maintenance therapy was evaluated by review of the medical notes. 398 patients were diagnosed with MAC from 1990 to 1999. 350 had a previous CD4 count below 50 cells/mm3. A total of 3208 patients had a nadir CD4 count of less than 50 cells/mm3 during the study period and contributed to a total follow-up of 6004 person-years. The incidence over the whole study period was 5.8 events per 100 person-years. In the time period of available ART the incidence of MAC was significantly reduced (1.4 versus 8.8 events per 100 person-years, p < 0.001). Being diagnosed after 1995 was the most powerful predictor of better survival (adjusted hazard ratio for death: 0.27; p < 0.001). None of 24 patients discontinuing maintenance therapy while on ART experienced recurrence of MAC during a total follow-up of 56.6 person-years (upper 95% confidence limit 5.3 per 100 person-years). Introducing ART has markedly reduced the risk of MAC for HIV-infected individuals with a history of very low CD4 counts. Survival after diagnosis of MAC has improved after ART became available. In patients responding to ART, discontinuation of maintenance therapy against M. avium may be safe.
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Calpain 3 is a member of the calpain family of calcium-dependent intracellular proteases. Thirteen years ago it was discovered that mutations in calpain 3 (CAPN3) result in an autosomal recessive and progressive form of limb girdle muscular dystrophy called limb girdle muscular dystrophy type 2A. While calpain 3 mRNA is expressed at high levels in muscle and appears to have some role in developmental processes, muscles of patients and mice lacking calpain 3 still form apparently normal muscle during prenatal development; thus, a functional calpain 3 protease is not mandatory for muscle to form in vivo but it is a pre-requisite for muscle to remain healthy. Despite intensive research in this field, the physiological substrates of the calpain 3 protein (hereafter referred to as CAPN3) and its alternatively spliced isoforms remain elusive. The existence of these multiple isoforms complicates the search for the physiological functions of CAPN3 and its pathophysiological role. In this review, we summarize the genetic and biochemical evidence that point to loss of function of the full-length isoform of CAPN3, also known as p94, as the pathogenic isoform. We also argue that its natural substrates must reside in its proximity within the sarcomere where it is stored in an inactive state anchored to titin. We further propose that CAPN3 has many attributes that make it ideally suited as a sensor of sarcomeric integrity and function, involved in its repair and maintenance. Loss of these CAPN3-mediated activities can explain the "progressive" development of muscular dystrophy.
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Diplomityön kohdeyrityksen liiketoiminta on kokenut viime aikoina merkittäviä muutoksia lisääntyneen volyymin, vaihtuneiden toimitilojen ja konsernin taloudellisesti haastavan tilanteen johdosta. Olosuhteiden muuttuessa ja taloudellisten vaikeuksien kasvaessa on tuotannonohjauksen kehittäminen jäänyt yksikössä takaa-alalle, mikä näkyy pitkittyneinä toimitusaikoina ja laskutusviiveenä, heikkona ohjattavuutena ja täten myös kannattavuuden huonontumisena. Työn tavoitteena onkin tutkia sähkömoottorihuoltotoiminnan nykytilaa ja löytää käytännönläheisiä ja nopeasti toteutettavissa olevia ratkaisuja tuotannonohjauksen kehittämiseksi. Työn teoreettisena viitekehyksenä käytettiin tuotannonohjauksen perusproblema-tiikkaa käsitteleviä teoksia, kuten myös tuotannonohjauksen kehityshankkeisiin liittyvää materiaalia. Tämän lisäksi työhön on pyritty saamaan lisänäkemystä suo-rittamalla benchmarking -vierailuja yhteistyöyrityksiin, jossa on hiljattain suoritettu vastaavan kaltaisia, onnistuneita tuotannonohjauksen kehityshankkeita. Työn empiirinen osuus jaoteltiin kahteen teemaan; nykytila-analyysiin ja toimenpide-ehdotuksiin. Nykytila-analyysi pyrittiin luomaan mahdollisimman kattavaksi sisällyttämällä siihen näkökulmia niin tuotannollisten lukujen kuin henkilöstön nä-kemysten perusteella. Analyysin pohjalta yritykselle laadittiin ehdotuksia käytän-nönläheisistä, nopeasti toteutettavissa olevista toimenpiteistä kuten myös ehdotuksia tuotannon jatkokehityksestä.
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The objective of this thesis is to better understand customer’s role in lean startup methodology. The aim is to find out how customers are involved in lean startup methodology implantation and increase the likelihood of new venture survival. This study emphasizes the usage of customers in shaping of new product development processes within companies, through iteration and constant communication. This communication facilitates the development of features that are requested by the customers and enhances the prospects of the new venture. The empirical part of the study is a single qualitative case study that uses action research to implement the lean startup methodology into a pre-revenue venture and examines its customer involvement processes. The studied case company is Karaoke d.o.o., developing a game called kParty. The study used the theory discussed in the literature review: customer involvement (in the survey and interviews conducted for the lean startup methodology), lean principles (through the implementation of lean startup methodology) and lean startup methodology, which are the central building parts of this thesis as a whole. The thesis contributes to the understanding of customer involvement in lean startup methodology, while giving practical implications of customer orientation and product market fitting.
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Mitochondria have an important role in cell metabolism, being the major site of ATP production via oxidative phosphorylation (OXPHOS). Accumulation of mtDNA mutations have been linked to the development of respiratory dysfunction, apoptosis, and aging. Base excision repair (BER) is the major and the only certain repair pathway existing in mitochondria that is in responsible for removing and repairing various base modifications as well as abasic sites (AP sites). In this research, Saccharomyces cerevisiae (S. cerevisiae) BER gene knockout strains, including 3 single DNA glycosylase gene knockout strains and Ap endonuclease (Apn 1 p) knockout strain were used to examine the importance of this DNA repair pathway to the maintenance of respiratory function. Here, I show that individual DNA glycosylases are nonessential in maintenance of normal function in yeast mitochondria, corroborating with previous research in mammalian experimental models. The yeast strain lacking Apn 1 p activity exhibits respiratory deficits, including inefficient and significantly low intracellular ATP level, which maybe due to partial uncoupling of OXPHOS. Growth of this yeast strain on respiratory medium is inhibited, but no evidence was found for increased ROS level in Apn 1 p mitochondria. This strain also shows an increased cell size, and this observation combined with an uncoupled OXPHOS may indicate a premature aging in the Apnlp knockout strain, but more evidence is needed to support this hypothesis. However, the BER is necessary for maintenance of mitochondrial function in respiring S.cerevisiae.
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Background: CVD is the second leading cause of death in Canada. Mastery and self-esteem are psychosocial factors, suggested to be emerging risk factors for CVD. Purpose: The purpose of the study was two-fold; first to establish whether mastery and self-esteem predicted adherence to maintenance CR; and second, whether mastery and self-esteem improved after a 6-month maintenance CR program. Methods: Data were collected at the Brock University Heart Institute. The study involved a sample of 98 participants. At intake to the program and 6-month follow-up, participants completed a questionnaire battery which included the Rosenberg Self-Esteem Scale and the Pearlin-Schooler Mastery Scale. Results: Mastery and self-esteem scores did not alter the likelihood of adherence to the CR program. Mastery and self-esteem did significantly improve after 6-months of CR amongst participants with the lowest exercise capacity. Conclusion: Maintenance CR does improve mastery and self-esteem amongst those with diminished exercise capacity.
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Many arthropods exhibit behaviours precursory to social life, including adult longevity, parental care, nest loyalty and mutual tolerance, yet there are few examples of social behaviour in this phylum. The small carpenter bees, genus Ceratina, provide important insights into the early stages of sociality. I described the biology and social behaviour of five facultatively social species which exhibit all of the preadaptations for successful group living, yet present ecological and behavioural characteristics that seemingly disfavour frequent colony formation. These species are socially polymorphic with both / solitary and social nests collected in sympatry. Social colonies consist of two adult females, one contributing both foraging and reproductive effort and the second which remains at the nest as a passive guard. Cooperative nesting provides no overt reproductive benefits over solitary nesting, although brood survival tends to be greater in social colonies. Three main theories explain cooperation among conspecifics: mutual benefit, kin selection and manipulation. Lifetime reproductive success calculations revealed that mutual benefit does not explain social behaviour in this group as social colonies have lower per capita life time reproductive success than solitary nests. Genetic pedigrees constructed from allozyme data indicate that kin selection might contribute to the maintenance of social nesting -, as social colonies consist of full sisters and thus some indirect fitness benefits are inherently bestowed on subordinate females as a result of remaining to help their dominant sister. These data suggest that the origin of sociality in ceratinines has principal costs and the great ecological success of highly eusociallineages occurred well after social origins. Ecological constraints such as resource limitation, unfavourable weather conditions and parasite pressure have long been considered some of the most important selective pressures for the evolution of sociality. I assessed the fitness consequences of these three ecological factors for reproductive success of solitary and social colonies and found that nest sites were not limiting, and the frequency of social nesting was consistent across brood rearing seasons. Local weather varied between seasons but was not correlated with reproductive success. Severe parasitism resulted in low reproductive success and total nest failure in solitary nests. Social colonies had higher reproductive success and were never extirpated by parasites. I suggest that social nesting represents a form of bet-hedging. The high frequency of solitary nests suggests that this is the optimal strategy when parasite pressure is low. However, social colonies have a selective advantage over solitary nesting females during periods of extreme parasite pressure. Finally, the small carpenter bees are recorded from all continents except Antarctica. I constructed the first molecular phylogeny of ceratinine bees based on four gene regions of selected species covering representatives from all continents and ecological regions. Maximum parsimony and Bayesian Inference tree topology and fossil dating support an African origin followed by an Old World invasion and New World radiation. All known Old World ceratinines form social colonies while New World species are largely solitary; thus geography and phylogenetic inertia are likely predictors of social evolution in this genus. This integrative approach not only describes the behaviour of several previously unknown or little-known Ceratina species, bu~ highlights the fact that this is an important, though previously unrecognized, model for studying evolutionary transitions from solitary to social behaviour.
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Tesis (Maestro en Ciencias de la Administración con Especialidad en Producción y Calidad) U.A.N.L. - 2001
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La démence d'Alzheimer est une maladie neurodégénérative caractérisée par une perte progressive et irreversible des fonctions cognitives et des compétences intellectuelles. La maladie d’Alzheimer se présente sous deux formes: la forme familiale ou précoce (EOAD) qui représente 5% des cas et elle est liée à des mutations génétiques affectant le métabolisme des peptides amyloïde; et la forme tardive ou sporadique (LOAD) qui représente 95% des cas mais son étiologie est encore mal définie. Cependant, le vieillissement reste le principal facteur de risque pour développer LOAD. Les changements épigénétiques impliquant des modifications des histones jouent un rôle crucial dans les maladies neurodégénératives et le vieillissement lié à l'âge. Des données récentes ont décrit LOAD comme un désordre de l'épigénome et ont associé ce trouble à l'instabilité génomique. Les protéines Polycomb sont des modificateurs épigénétiques qui induisent le remodelage de la chromatine et la répression des gènes à l'hétérochromatine facultative. Nous rapportons que les souris hétérozygotes pour une protéine Polycomb développent avec l'âge un trouble neurologique ressemblant à LOAD caractérisé par l’altération des fonctions cognitives, la phosphorylation de la protéine tau, l'accumulation des peptides amyloïde, et le dysfonctionnement synaptique. Ce phénotype pathologique est précédé par la décondensation de l’hétérochromatine neuronale et l'activation de la réponse aux dommages à l'ADN. Parallèlement, une réduction d’expression de polycomb, malformations de l'hétérochromatine neuronale, et l'accumulation de dommages à l'ADN étaient également présents dans les cerveaux de patients LOAD. Remarquablement, les dommages de l'ADN ne sont pas distribués de façon aléatoire sur le génome mais sont enrichis au niveau des séquences répétitives. Les conclusions présentées dans cette thèse ont identifié des modifications épigénétiques spécifiques qui conduisent à une instabilité génomique aberrante menant à la formation de LOAD. Ces résultats vont aider au développement de nouveaux traitements qui peuvent potentiellement ralentir la neurodégénérescence.
Resumo:
Le surenroulement de l’ADN est important pour tous les processus cellulaires qui requièrent la séparation des brins de l’ADN. Il est régulé par l’activité enzymatique des topoisomérases. La gyrase (gyrA et gyrB) utilise l’ATP pour introduire des supertours négatifs dans l’ADN, alors que la topoisomérase I (topA) et la topoisomérase IV (parC et parE) les éliminent. Les cellules déficientes pour la topoisomérase I sont viables si elles ont des mutations compensatoires dans un des gènes codant pour une sous-unité de la gyrase. Ces mutations réduisent le niveau de surenroulement négatif du chromosome et permettent la croissance bactérienne. Une de ces mutations engendre la production d'une gyrase thermosensible. L’activité de surenroulement de la gyrase en absence de la topoisomérase I cause l’accumulation d’ADN hyper-surenroulé négativement à cause de la formation de R-loops. La surproduction de la RNase HI (rnhA), une enzyme qui dégrade l’ARN des R-loops, permet de prévenir l’accumulation d’un excès de surenroulement négatif. En absence de RNase HI, des R-loops sont aussi formés et peuvent être utilisés pour déclencher la réplication de l’ADN indépendamment du système normal oriC/DnaA, un phénomène connu sous le nom de « constitutive stable DNA replication » (cSDR). Pour mieux comprendre le lien entre la formation de R-loops et l’excès de surenroulement négatif, nous avons construit un mutant conditionnel topA rnhA gyrB(Ts) avec l’expression inductible de la RNase HI à partir d’un plasmide. Nous avons trouvé que l’ADN des cellules de ce mutant était excessivement relâché au lieu d'être hypersurenroulé négativement en conditions de pénurie de RNase HI. La relaxation de l’ADN a été montrée comme étant indépendante de l'activité de la topoisomérase IV. Les cellules du triple mutant topA rnhA gyrB(Ts) forment de très longs filaments remplis d’ADN, montrant ainsi un défaut de ségrégation des chromosomes. La surproduction de la topoisomérase III (topB), une enzyme qui peut effectuer la décaténation de l’ADN, a corrigé les problèmes de ségrégation sans toutefois restaurer le niveau de surenroulement de l’ADN. Nous avons constaté que des extraits protéiques du mutant topA rnhA gyrB(Ts) pouvaient inhiber l’activité de surenroulement négatif de la gyrase dans des extraits d’une souche sauvage, suggérant ainsi que la pénurie de RNase HI avait déclenché une réponse cellulaire d’inhibition de cette activité de la gyrase. De plus, des expériences in vivo et in vitro ont montré qu’en absence de RNase HI, l’activité ATP-dépendante de surenroulement négatif de la gyrase était inhibée, alors que l’activité ATP-indépendante de cette enzyme demeurait intacte. Des suppresseurs extragéniques du défaut de croissance du triple mutant topA rnhA gyrB(Ts) qui corrigent également les problèmes de surenroulement et de ségrégation des chromosomes ont pour la plupart été cartographiés dans des gènes impliqués dans la réplication de l’ADN, le métabolisme des R-loops, ou la formation de fimbriae. La deuxième partie de ce projet avait pour but de comprendre les rôles des topoisomérases de type IA (topoisomérase I et topoisomérase III) dans la ségrégation et la stabilité du génome de Escherichia coli. Pour étudier ces rôles, nous avons utilisé des approches de génétique combinées avec la cytométrie en flux, l’analyse de type Western blot et la microscopie. Nous avons constaté que le phénotype Par- et les défauts de ségrégation des chromosomes d’un mutant gyrB(Ts) avaient été corrigés en inactivant topA, mais uniquement en présence du gène topB. En outre, nous avons démontré que la surproduction de la topoisomérase III pouvait corriger le phénotype Par- du mutant gyrB(Ts) sans toutefois corriger les défauts de croissance de ce dernier. La surproduction de topoisomérase IV, enzyme responsable de la décaténation des chromosomes chez E. coli, ne pouvait pas remplacer la topoisomérase III. Nos résultats suggèrent que les topoisomérases de type IA jouent un rôle important dans la ségrégation des chromosomes lorsque la gyrase est inefficace. Pour étudier le rôle des topoisomérases de type IA dans la stabilité du génome, la troisième partie du projet, nous avons utilisé des approches génétiques combinées avec des tests de « spot » et la microscopie. Nous avons constaté que les cellules déficientes en topoisomérase I avaient des défauts de ségrégation de chromosomes et de croissance liés à un excès de surenroulement négatif, et que ces défauts pouvaient être corrigés en inactivant recQ, recA ou par la surproduction de la topoisomérase III. Le suppresseur extragénique oriC15::aph isolé dans la première partie du projet pouvait également corriger ces problèmes. Les cellules déficientes en topoisomérases de type IA formaient des très longs filaments remplis d’ADN d’apparence diffuse et réparti inégalement dans la cellule. Ces phénotypes pouvaient être partiellement corrigés par la surproduction de la RNase HI ou en inactivant recA, ou encore par des suppresseurs isolés dans la première partie du projet et impliques dans le cSDR (dnaT18::aph et rne59::aph). Donc, dans E. coli, les topoisomérases de type IA jouent un rôle dans la stabilité du génome en inhibant la réplication inappropriée à partir de oriC et de R-loops, et en empêchant les défauts de ségrégation liés à la recombinaison RecA-dépendante, par leur action avec RecQ. Les travaux rapportés ici révèlent que la réplication inappropriée et dérégulée est une source majeure de l’instabilité génomique. Empêcher la réplication inappropriée permet la ségrégation des chromosomes et le maintien d’un génome stable. La RNase HI et les topoisomérases de type IA jouent un rôle majeur dans la prévention de la réplication inappropriée. La RNase HI réalise cette tâche en modulant l’activité de surenroulement ATP-dependante de la gyrase, et en empêchant la réplication à partir des R-loops. Les topoisomérases de type IA assurent le maintien de la stabilité du génome en empêchant la réplication inappropriée à partir de oriC et des R-loops et en agissant avec RecQ pour résoudre des intermédiaires de recombinaison RecA-dépendants afin de permettre la ségrégation des chromosomes.
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Some study has been made earlier, but no attempt has ever been made to make the study comprehensive and comparative. There exists also no information as to the working of the system. Hence the work is undertaken to provide first hand knowledge of the legal institutions that had handled and now handles annually large masses of deprived and neglected population. An investigation is also necessary to know the legal and social characteristics of the jurisdiction enjoined on the court so that this will help compare the law in the statute with the law and practice. The evaluation of the working system in the changed social atmosphere is also an urgent need of the hour
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To provide maintenance engineering community with a model named “Maintenance quality function deployment” (MQFD) for nourishing the synergy of quality function deployment (QFD) and total productive maintenance (TPM) and enhancing maintenance quality of products and equipment.The principles of QFD and TPM were studied. MQFD model was designed by coupling these two principles. The practical implementation feasibility of MQFD model was checked in an automobile service station.Both QFD and TPM are popular approaches and several benefits of implementing them have been reported worldwide. Yet the world has not nourished the synergic power of integrating them. The MQFD implementation study reported in this paper has revealed its practical validity
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Refiners today operate their equipment for prolonged periods without shutdown. This is primarily due to the increased pressures of the market resulting in extended shutdown-to-shutdown intervals. This places extreme demands on the reliability of the plant equipment. The traditional methods of reliability assurance, like Preventive Maintenance, Predictive Maintenance and Condition Based Maintenance become inadequate in the face of such demands. The alternate approaches to reliability improvement, being adopted the world over are implementation of RCFA programs and Reliability Centered Maintenance. However refiners and process plants find it difficult to adopt this standardized methodology of RCM mainly due to the complexity and the large amount of analysis that needs to be done, resulting in a long drawn out implementation, requiring the services of a number of skilled people. These results in either an implementation restricted to only few equipment or alternately, one that is non-standard. The paper presents the current models in use, the core requirements of a standard RCM model, the alternatives to classical RCM, limitations in the existing model, classical RCM and available alternatives to RCM and will then go on to present an ‗Accelerated‘ approach to RCM implementation, that, while ensuring close conformance to the standard, does not place a large burden on the implementers
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The Massachusetts Institute of Technology (MIT) submits this proposal for the Enterprise Value Phase of the Lean Aerospace Initiative (LAI) in response to the October 9, 2002 Request for Proposal (RFP) F33615-02-2-5501 from the Air Force Research Laboratory (AFRL/MLKT), Wright-Patterson Air Force Base, Ohio. This proposal addresses the conduct of the LAI as set forth in the Enterprise Value Phase Concept of Operations (final draft dated 5 June 2002. The creation of this Enterprise Value Phase Concept of Operations (ConOps) was the result of extensive interaction among all stakeholders in the LAI consortium. The proposed products and research topics have been developed by the MIT LAI team based on this extended interaction with the Lean Aerospace Initiative consortium members during the concept of operations development. This proposal is in consonance with the Enterprise Value Phase vision, and mission as set forth in the concept of operations so as to meet stakeholder needs to achieve the goals and deliverables desired, prioritized to fit available funding.
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This report is a formal documentation of the results of an assessment of the degree to which Lean Principles and Practices have been implemented in the US Aerospace and Defense Industry. An Industry Association team prepared it for the DCMA-DCAAIndustry Association “Crosstalk” Coalition in response to a “Crosstalk” meeting action request to the industry associations. The motivation of this request was provided by the many potential benefits to system product quality, affordability and industry responsiveness, which a high degree of industry Lean implementation can produce.