991 resultados para MANUFACTURING STRATEGIES
Resumo:
The variation in nitrogen use strategies and photosynthetic pathways among vascular epiphyte families was addressed in a white-sand vegetation in the Brazilian Central Amazon. Foliar nitrogen and carbon concentrations and their isotopic composition (δ15N and δ13C, respectively) were measured in epiphytes (Araceae, Bromeliaceae and Orchidaceae) and their host trees. The host tree Aldina heterophylla had higher foliar N concentration and lower C:N ratio (2.1 ± 0.06% and 23.6 ± 0.8) than its dwellers. Tree foliar δ15N differed only from that of the orchids. Comparing the epiphyte families, the aroids had the highest foliar N concentration and lowest C:N ratios (1.4 ± 0.1% and 34.9 ± 4.2, respectively). The orchids had more negative foliar δ15N values (-3.5 ± 0.2) than the aroids (-1.9 ± 0.7) and the bromeliads (-1.1 ± 0.6). Within each family, aroid and orchid taxa differed in relation to foliar N concentrations and C:N ratios, whereas no internal variation was detected within bromeliads. The differences in foliar δ15N observed herein seem to be related to the differential reliance on the available N sources for epiphytes, as well as to the microhabitat quality within the canopy. In relation to epiphyte foliar δ13C, the majority of epiphytes use the water-conserving CAM-pathway (δ13C values around -17), commonly associated with plants that live under limited and intermittent water supply. Only the aroids and one orchid taxon indicated the use of C3-pathway (δ13C values around -30).
Resumo:
Transplantation of mobilized peripheral blood stem cells (PBSC) for rescue of bone marrow function after high-dose chemo-/radiotherapy is widely used in hematologic malignancies and solid tumors. Mobilization of stem cells to the peripheral blood can be achieved by cytokine treatment of the patients. The main advantage of autologous PBSC transplantation over bone marrow transplantation is the faster recovery of neutrophil and platelet counts. The threshold number of PBSC required for adequate rescue of bone marrow is thought to be about 2 x 106 CD34+ cells/kg, if the stem cells are collected by leukapheresis and subsequently cryopreserved. We show that this critical number could be further reduced to as few as 0.2 x 106 cells/kg. In 30 patients with multiple myeloma and 25 patients with bad risk lymphoma 1 liter of granulocyte colony-stimulating factor (G-CSF)-mobilized unprocessed whole blood (stored at 4oC for 1-3 days) was used for transplantation. Compared to a historical control group, a significant reduction in the duration of neutropenia, thrombocytopenia and the length of hospital stay was documented. Furthermore, the effect of stem cell support was reflected by a lower need for platelet and red cell transfusions and a reduced antibiotic use. Considering the data as a whole, a cost saving of about 50% was achieved. To date, this easy to perform method of transplantation is only feasible following high-dose therapies that are completed within 72 h, since longer storage of unprocessed blood is accompanied by a substantial loss of progenitor cell function. Ongoing investigations include attempts to prolong storage times for whole blood
Resumo:
Stimulation of the mammalian immune system by administration of plasmid DNA has been shown to be an important approach for vaccine development against several pathogens. In the present study we investigated the use of DNA vaccines to induce immune responses against an enteric bacterial pathogen, enterotoxigenic Escherichia coli (ETEC). Three plasmid vectors encoding colonization factor antigen I (CFA/I), an ETEC fimbrial adhesin, were constructed. Eukaryotic cells transfected with each of these plasmids expressed the heterologous antigen in different compartments: bound to the cytoplasmic membrane (pRECFA), accumulated in the cytoplasm (pPolyCFA) or secreted to the outside medium (pBLCFA). BALB/c mice were intramuscularly (im) inoculated with purified plasmid DNA and the systemic, cellular and secreted CFA/I-specific immune responses were analyzed. The results showed that all three DNA vaccine formulations could elicit CFA/I-specific immune responses. Moreover, cellular location of the plasmid-encoded CFA/I seems to have an important role in the induced immune response. Taken together, these results indicate that DNA vaccines also represent a promising approach against enteric bacterial pathogens.
Resumo:
The induction of systemic (IgG) and mucosal (IgA) antibody responses against the colonization factor I antigen (CFA/I) of enterotoxigenic Escherichia coli (ETEC) was evaluated in mice primed with an intramuscularly delivered CFA/I-encoding DNA vaccine followed by two oral immunizations with a live recombinant Salmonella typhimurium vaccine strain expressing the ETEC antigen. The booster effect induced by the oral immunization was detected two weeks and one year after the administration of the DNA vaccine. The DNA-primed/Salmonella-boosted vaccination regime showed a synergistic effect on the induced CFA/I-specific systemic and secreted antibody levels which could not be attained by either immunization strategy alone. These results suggest that the combined use of DNA vaccines and recombinant Salmonella vaccine strains can be a useful immunization strategy against enteric pathogens.
Resumo:
The objective of this research is to demonstrate the use of Lean Six Sigma methodology in a manufacturing lead time improvement project. Moreover, the goal is to develop working solutions for the target company to improve its manufacturing lead time. The theoretical background is achieved through exploring the literature of Six Sigma, Lean and Lean Six Sigma. The development will be done in collaboration with the related stakeholders, by following the Lean Six Sigma improvement process DMAIC and by analyzing the process data from the target company. The focus of this research is in demonstrating how to use Lean Six Sigma improvement process DMAIC in practice, rather than in comparing Lean Six Sigma to other improvement methodologies. In order to validate the manufacturing system’s current state, improvement potential and solutions, statistical tools such as linear regression analysis were used. This ensured that all the decisions were as heavily based on actual data as possible. As a result of this research, a set of solutions were developed and implemented in the target company. These solutions included batch size reduction, bottleneck shift, first-in first-out queuing and shifting a data entry task from production planners to line workers. With the use of these solutions, the target company was able to reduce its manufacturing lead time by over one third.
Resumo:
Salivary cortisol is an index of plasma free cortisol and is obtained by a noninvasive procedure. We have been using salivary cortisol as a tool for physiological and diagnostic studies, among them the emergence of circadian rhythm in preterm and term infants. The salivary cortisol circadian rhythm in term and premature infants was established between 8 and 12 postnatal weeks. In the preterm infants the emergence of circadian rhythm was parallel to the onset of sleep rhythm. We also studied the use of salivary cortisol for screening for Cushing's syndrome (CS) in control and obese outpatients based on circadian rhythm and the overnight 1 mg dexamethasone (DEX) suppression test. Salivary cortisol was suppressed to less than 100 ng/dl after 1 mg DEX in control and obese patients. A single salivary cortisol measurement at 23:00 h and again after 1 mg DEX above the 90th percentile of the obese group values had sensitivity and specificity of 93 and 93% (23:00 h), and 91 and 94% (after DEX), respectively. The sensitivity improved to 100% when we combined both parameters. We also studied 11 CS children and 21 age-matched primary obese children for whom salivary cortisol sensitivity and specificity were 100/95% (23:00 h), and 100/95% (1 mg DEX), respectively. Similar to adults, sensitivity and specificity of 100% were obtained by combining 23:00 h and 1 mg DEX. The measurement of salivary cortisol is a useful tool for physiological studies and for the diagnosis of CS in children and adults on an outpatient basis.
Resumo:
Adrenocortical carcinoma is a highly malignant neoplasm with an incidence of two per million people per year. Several treatment strategies have resulted in temporary or partial tumor regression but very few cases have attained long survival. Surgical resection of the primary tumor and metastases is most effective. Several chemotherapeutic protocols have been employed with variable success. Mitotane (o,p'-DDD) is an adrenalytic drug effective in inducing a tumor response in 33% of patients treated. Mitotane requires metabolic transformation for therapeutic action. Tumors may vary in their ability to metabolize mitotane and the ability of tumors to transform mitotane may predict the clinical response to the drug. Preliminary data show a possible correlation between metabolic activity of neoplastic adrenocortical tissue and response to mitotane. We have attempted to develop mitotane analogs with enhanced adrenalytic effect. Compared to mitotane, a di-chloro compound, the bromo-chloro and di-bromo analogs appear to have a greater effect. Future approaches to the treatment of adrenocortical carcinoma are likely to be based on blocking or reversing the biological mechanisms of tumorigenesis. Angiogenic and chemotactic mechanisms may play a role in adrenal tumor growth and inhibition of these mechanisms may result in inhibition of tumor growth. New mitotane analogs with greater adrenalytic potential could be a promising approach to developing more effective and selective therapies for adrenal cancer. Alternative approaches should attempt to suppress tumor growth by means of compounds with anti-angiogenic and anti-chemotactic activity.
Resumo:
The purpose of this study was to expand the applicability of supplier segmentation and development approaches to the project-driven construction industry. These practices are less exploited and not well documented in this operational environment compared to the process-centric manufacturing industry. At first, portfolio models to supply base segmentation and various supplier development efforts were investigated in literature review. A step-wise framework was structured for the empirical research. The empirical study employed multiple research methods in three case studies in a large Finnish construction company. The first study categorized the construction item classes into the purchasing portfolio and positioned suppliers to the power matrix by investigating buyer-supplier relations. Using statistical tests, the study also identified factors that affect suppliers’ performance. The final case study identified improvement areas of the interface between a main contractor and one if its largest suppliers. The final results indicate that only by assessing the supply base in a holistic manner and the power circumstances in it, buyers comprehend how to best establish appropriate supplier development strategies in the project environment.
Resumo:
The exposure of fish to air is normally expected to interfere with the nitrogen excretion process. Hoplias malabaricus and Hoplerythrinus unitaeniatus, two teleost species, display distinct behaviors in response to decreases in natural reservoir water levels, although they may employ similar biochemical strategies. To investigate this point, plasma levels of ammonia, urea, uric acid, and the two urea cycle enzymes, ornithine carbamoyl transferase (OCT) and arginase (ARG), as well as glutamine synthetase (GS) were determined for both species after exposure to air. Plasma ammonia increased gradually during exposure to air, but only H. malabaricus showed increased concentrations of urea. Plasma uric acid remained very low in both fish. Enzymatic activities (mean ± SD, µmol min-1 g protein-1) of H. malabaricus showed significant increases (P<0.05, N = 6) in OCT from 0.84 ± 0.05 to 1.42 ± 0.03, in ARG from 8.07 ± 0.47 to 9.97 ± 0.53 and in GS from 1.15 ± 0.03 to 2.39 ± 0.04. The OCT and ARG enzymes remained constant in H. unitaeniatus (N = 6), but GS increased from 1.49 ± 0.02 to 2.06 ± 0.03. Although these species are very closely related and share the same environment, their biochemical strategies in response to exposure to air or to increased plasma ammonia are different.
Resumo:
Laser additive manufacturing (LAM), known also as 3D printing, is a powder bed fusion (PBF) type of additive manufacturing (AM) technology used to manufacture metal parts layer by layer by assist of laser beam. The development of the technology from building just prototype parts to functional parts is due to design flexibility. And also possibility to manufacture tailored and optimised components in terms of performance and strength to weight ratio of final parts. The study of energy and raw material consumption in LAM is essential as it might facilitate the adoption and usage of the technique in manufacturing industries. The objective this thesis was find the impact of LAM on environmental and economic aspects and to conduct life cycle inventory of CNC machining and LAM in terms of energy and raw material consumption at production phases. Literature overview in this thesis include sustainability issues in manufacturing industries with focus on environmental and economic aspects. Also life cycle assessment and its applicability in manufacturing industry were studied. UPLCI-CO2PE! Initiative was identified as mostly applied exiting methodology to conduct LCI analysis in discrete manufacturing process like LAM. Many of the reviewed literature had focused to PBF of polymeric material and only few had considered metallic materials. The studies that had included metallic materials had only measured input and output energy or materials of the process and compared to different AM systems without comparing to any competitive process. Neither did any include effect of process variation when building metallic parts with LAM. Experimental testing were carried out to make dissimilar samples with CNC machining and LAM in this thesis. Test samples were designed to include part complexity and weight reductions. PUMA 2500Y lathe machine was used in the CNC machining whereas a modified research machine representing EOSINT M-series was used for the LAM. The raw material used for making the test pieces were stainless steel 316L bar (CNC machined parts) and stainless steel 316L powder (LAM built parts). An analysis of power, time, and the energy consumed in each of the manufacturing processes on production phase showed that LAM utilises more energy than CNC machining. The high energy consumption was as result of duration of production. Energy consumption profiles in CNC machining showed fluctuations with high and low power ranges. LAM energy usage within specific mode (standby, heating, process, sawing) remained relatively constant through the production. CNC machining was limited in terms of manufacturing freedom as it was not possible to manufacture all the designed sample by machining. And the one which was possible was aided with large amount of material removed as waste. Planning phase in LAM was shorter than in CNC machining as the latter required many preparation steps. Specific energy consumption (SEC) were estimated in LAM based on the practical results and assumed platform utilisation. The estimated platform utilisation showed SEC could reduce when more parts were placed in one build than it was in with the empirical results in this thesis (six parts).
Resumo:
To inhibit an ongoing flow of thoughts or actions has been largely considered to be a crucial executive function, and the stop-signal paradigm makes inhibitory control measurable. Stop-signal tasks usually combine two concurrent tasks, i.e., manual responses to a primary task (go-task) are occasionally countermanded by a stimulus which signals participants to inhibit their response in that trial (stop-task). Participants are always instructed not to wait for the stop-signal, since waiting strategies cause the response times to be unstable, invalidating the data. The aim of the present study was to experimentally control the strategies of waiting deliberately for the stop-signal in a stop-task by means of an algorithm that measured the variation in the reaction times to go-stimuli on-line, and displayed a warning legend urging participants to be faster when their reaction times were more than two standard deviations of the mean. Thirty-four university students performed a stop-task with go- and stop-stimuli, both of which were delivered in the visual modality and were lateralized within the visual field. The participants were divided into two groups (group A, without the algorithm, vs group B, with the algorithm). Group B exhibited lower variability of reaction times to go-stimuli, whereas no significant between-group differences were found in any of the measures of inhibitory control, showing that the algorithm succeeded in controlling the deliberate waiting strategies. Differences between deliberate and unintentional waiting strategies, and anxiety as a probable factor responsible for individual differences in deliberate waiting behavior, are discussed.
Resumo:
The estimation of losses plays a key role in the process of building any electrical machine. How to estimate those losses while designing any machine; by obtaining the characteristic of the electrical steel from the catalogue and calculate the losses. However, this way is inaccurate since the electrical steel performs several manufacturing processes during the process of building any machine, which affects directly the magnetic property of the electrical steel and accordingly the characteristic of the electrical steel will be affected. That means the B–H curve of the steel that was obtained from the catalogue will be changed. Moreover, during loading and rotating the machine, some important changes occur to the B–H characteristic of the electrical steel such as the stress on the laminated iron. Accordingly, the pre-estimated losses are completely far from the actual losses because they were estimated based on the data of the electrical steel obtained from the catalogue. So in order to estimate the losses precisely significant factors of the manufacturing processes must be included. The paper introduces the systematic estimation of the losses including the effect of one of the manufacturing factors. Similarly, any other manufacturing factor can be included in the pre-designed losses estimations.