1000 resultados para pattern transfer
Resumo:
The importance of Technology Transfer activities of companies is underpinned by the changes in technological and economic environments. However, there is still a significant gap in defining possible ways for Technology Transfer projects effectiveness improvement. The Master’s Thesis overviews common problems faced by the companies in implementation of Technology Transfer projects and examines Lean management principles as possible way to improve its effectiveness. Based on the analysis of the relevant scientific literature and results of the survey, conducted among the firms of different types, the approach to Technology Transfer projects implementation with the use of Lean management principles is proposed. The approach serves to solve some of the important problems faced by the managers of Technology Transfer projects. It is envisaged that this approach can help to increase overall Technology Transfer projects’ effectiveness.
Resumo:
Lipid movement in cells occurs by a variety of methods. Lipids diffuse freely along the lateral plane of a membrane and can translocate between the lipid leaflets, either spontaneously or with the help of enzymes. Lipid translocation between the different cellular compartments predominantly takes place through vesicular transport. Specialized lipid transport proteins (LTPs) have also emerged as important players in lipid movement, as well as other cellular processes. In this thesis we have studied the glycolipid transport protein (GLTP), a protein that transports glycosphingolipids (GSLs). While the in vitro properties of GLTP have been well characterized, its cell biological role remains elusive. By altering GSL and GLTP levels in cells, we have extracted clues towards the protein's function. Based on the results presented in this thesis and in previous works, we hypothesize that GLTP is involved in the GSL homeostasis in cells. GLTP most likely functions as a transporter or sensor of newly synthesized glucosylceramide (GlcCer), at or near the site of GlcCer synthesis. GLTP also seems to be involved in the synthesis of globotriacylceramide, perhaps in a manner that is similar to that of the fourphosphate adaptor protein 2, another GlcCer-transporting LTP. Additionally, we have developed and studied a novel method of introducing ceramides to cells, using a solvent-free approach. Ceramides are important lipids that are implicated in several cellular functions. Their role as proapoptotic molecules is particularly evident. Ceramides form stable bilayer structures when complexed with cholesterol phosphocholine (CholPC), a large-headgroup sterol. By adding ceramide/CholPC complexes to the growth medium, various chain length ceramides were successfully delivered to cells in culture. The uptake rate was dependent on the chain length of the ceramide, where shorter lipids were internalized more quickly. The rate of uptake also determined how the cells metabolised the ceramides. Faster uptake favored conversion of ceramide to GlcCer, whereas slower delivery resulted mainly in breakdown of the lipid.
Resumo:
As reactive extraction grown more and more popular in a variety of technological applications, optimizing its performance becomes more and more important. The process of complex formation is affected by a great number of both physical and chemical properties of all the components involved, and sometimes their interference with one another makes improving the effectiveness of such processes very difficult. In this Master’s Theses, the processes of complex formation between the aqueous phase - represented by copper sulfate water solution, and organic phase – represented by Acorga M5640 solvent extractor, were studied in order to establish the effect these components have on reactive extraction performance and to determine which step is bottlenecking the process the most.
Resumo:
This study was a comparative investigation of face-toface (i.e., proximate) and computer-mediated written (i.e., graphic) pre-writing conferences. The participants in this study were advanced English as a second language students. The 2 types of conferences were compared in terms of textual features, participation, and the . degree to which they were on topic. Moreover, drafts written after the 2 types of conferences were compared in terms of textual features, and the degree to which they were related to the conferences. Students produced an equivalent amount of discourse in an equivalent amount of time in the 2 types of conferences. The discourse in graphic conferences displayed greater lexical range, and some evidence suggests that it was less on-topic. Both these results likely occurred because the graphic conferences contained more discourse demonstrating interactive competence. Participation in graphic conferences was found to be as balanced or more balanced among students, and among students and the group leader combined. Overall, the drafts produced after the 2 types of conferences were of equivalent length and topical range, but some evidence suggests that drafts written after proximate conferences were more related to the conferences.
Resumo:
This study examined whether daily classroom meetings resulted in the positive transfer of conflict resolution information and skills beyond the formal classroom setting and into the classroom. A control group of sixteen Grade five students received three weeks of conflict resolution training and an experimental group of nineteen Grade five students fi-om the same school received three weeks of conflict resolution training followed by three additional weeks of class meetings. Pretest measures were taken via a scaled questionnaire and short answer questions before the conflict resolution lessons began for the following skills: knowledge of conflict resolution; conflict resolution behaviour; and attitude about using conflict resolution to resolve problems with other people. Posttest measures examined conflict resolution skills following involvement in the study. Students chosen randomly and both teachers were interviewed following the study. The teachers were again interviewed three months after the study. Teacher journal notes rounded out the data. The results of the study indicated that the Grade five boys who participated in three weeks of conflict resolution training did not increase their conflict resolution skills in any of the areas examined. Girls who participated in three weeks of conflict resolution training did not improve in two areas (i.e., behaviour, knowledge) and became less positive about using verbal mediation to resolve conflicts. The Grade five students who participated in three weeks of training and three weeks of class meetings obtained different results. The boys improved significantly in their ability to use verbal mediation to resolve conflicts and were more positive about verbal mediation. They did not become more knowledgeable about verbal mediation. The girls who participated in three weeks of training and three weeks of class meetings were more knowledgeable of conflict resolution and used conflict resolution to solve problems with other people. However, they were significantly less positive about using these skills to resolve problems.
Resumo:
The human a-tocopherol transfer protein (h-a-TTP) is understood to be the entity responsible for the specific retention of a-tocopherol (a-toc) in human tissues over all other forms of vitamin E obtained from the diet. a-Tocopherol is the most biologically active form of vitamin E, and to date has been studied extensively with regard to its antioxidant properties and its role of terminating membrane lipid peroxidation chain reactions. However, information surrounding the distribution of a-tocopherol, specifically its delivery to intracellular membranes by a-TTP, is still unclear and the molecular factors influencing transfer remain elusive. To investigate the mechanism of ligand transfer by the h-a-TTP, a fluorescent analogue of a-toc has been used in the development of a fluorescence resonance energy transfer (FRET) assay. (/?)-2,5,7,8-tetramethyl-2-[9-(7-nitro-benzo[l,2,5]oxdiazol-4-ylamino)-nonyl]- chroman-6-ol (NBD-toc) has allowed for the development of the FRET-based ligand transfer assay. This ligand has been utilized in a series of experiments where changes were made to acceptor lipid membrane concentration and composition, as well as to the ionic strength and viscosity of the buffer medium. Such changes have yielded evidence supporting a collisional mechanism of ligand transfer by a-TTP, and have brought to light a new line of inquiry pertaining to the nature of the forces governing the collisional transfer interaction. Through elucidation of the transfer mechanism type, a deeper understanding of the transfer event and the in vivo fate of a-tocopherol have been obtained. Furthermore, the results presented here allow for a deeper investigation of the forces controlling the collisional protein-membrane interaction and their effect on the transfer of a-toc to membranes. Future investigation in this direction will raise the possibility of a complete understanding of the molecular events surrounding the distribution of a-toc within the cell and to the body's tissues.
Resumo:
To further understand in vivo localization and trafficking of a-tocopherol (a-Toe), the most biologically active form of vitamin E, between lipid environments, tocopherols are required that can be followed by teclu1iques such as confocal microscopy and fluorescence resonance energy transfer (FRET) assays. To this end, sixteen fluorescent analogues of a-tocopherol (la-d [(1)anthroy loxy -a-tocopherols, A O-a-Toes], 2a-d [w-nitro benzoxadiazole-a-tocopherols, NBD-aToes], 3a-d [w-dansyl-a-tocopherols, DAN-a-Toes], and 4a-d [w-N-methylanthranilamide-atocopherols, NMA-a-TocsD were prepared by substituting fluorescent labels at the terminus of w-functionalized alkyl chains extending from C-2 of the chroman ring while retaining key binding features of the natural ligand. These compounds were prepared starting from (S)-Trolox® acid VIa esterification, protection, and reduction producing the silyl-protected (S)-Trolox aldehyde that was coupled using Wittig chemistry to different w-hydroxyalkylphosphonium bromides. Reduction of the alkene generated the w-hydroxy functionalized 2-n-alkyl intermediates 9a-d having the necessary 2R stereochemistry. A series of functional group manipulations including mesylation, substitution with azide, and hydride reduction provided w-amino functionalized intermediates 12a-d as well. Coupling intermediates 9a-d and 12a-d with the selected fluorophores (9- anthracene carboxylic acid, 4-chloro-7-nitrobenz-2-oxa-l,3-diazole, 5- dimethylaminonapthalene-l-sulfonyl chloride, and I-methyl-2H-3,1-benzoxazine-2,4(1H)dione), followed by deprotection of the phenolic silyl group, gave the desired fluorescent ligands la-d, 2a-d, 3a-d and 4a-d in good yield. Assessment of their binding affinities with recombinant human a-tocopherol transfer protein (ha-TTP) utilizing fluorescent titration binding assays identified competent ligands for further use in protein studies. Compounds Id (C9-AO-a-Toc) and 2d (C9-NBD-a-Toc) both having nonyl alkyl chain extensions between the chromanol and fluorophore were shown to bind specifically to ha-TTP with dissociation constants (KdS) of approximately 280 nM and 55 nM respectively, as compared to 25 nM for the natural ligand 2R,4'R,^'R-a-tocophQxoL.
Resumo:
Young soybean plants (Glycine ~. L. cultivar Harosoy '63), grown under controlled conditions, were exposed to gamma radiation on a single occasion. One hour following exposure to 3,750 rads, the mature trifoliate leaf of the soybean plant was isolated in a closed system and permitted to photoassimilate approximately 1-5 pCi of 14C02 for 15 minutes. After an additional 45 minute-period, the plant was sacrificed and the magnitude of translocation and distribution pattern of 14C determined. In the non-irradiated plants 18~ of the total 14C recovered was outside the fed leaf blades and of this translocated 14c, 28~ was above the node of the fed leaf, 38~ in the stem below the node, 28~ in the roots and 7~ in the petiole. As well, in the irradiated plants, a smaller per cent (6~) of the total 14 C recovered was exported out of the source leaf blades. Of this translocated 14c , a smaller per cent (20~) was found in the apical region above the node of the source leaf and a higher per cent (45~) was recovered from the stem below the node and in the petiole (11~). The per cent of exported 14 C recovered from the root was unaffected by the radiation. Replacement of the shoot apex with 20 ppm IAA immediately following irradiation, only J partially increased the magnitude of translocation but did completely restore the pattern of distribution to that observed in the non-irradiated plants. From supplementary studies showing a radiationinduced reduction of photosynthetic rates in the source leaf and a reduction of the cumulative stem and leaf lengths in the apical sink region, the observed effects of radiation on the translocation process have been correlated to damage incurred by the source and sink regions. These data suggest that the reduction in the magnitude of translocation is the result of damage to both the source and sink regions rather than the phloem conducting tissue itself, whereas the change in the pattern of translocation is probably the result of a reduced rate of 14C-assimilate movement caused by a radiation-induced decrease of sink metabolism, especially the decrease in the metabolism of the apical sink.
Resumo:
An in vitro investigation of some important factors controlling the activity of chitin synthase in cell-free extracts of two Mortierella species has been carried out. Mixed membrane fractions from mycelial homogenates of Mortierella candelabrum and Mortierella pusilla were found to catalyse the transfer of N-acetylglucosamine from UDP-N-acetylglucosamine into an insoluble product characterized as chitin by its insolubility in weak acid and alkali, and the release of glucosamine and diacetylchitobiose on hydrolysis with a strong acid and chitinase, respectively. Apparent Km values for UDP-GlcNAc were 1.8 mM and 2.0 mM for M. pusilla and ~ candelabrum, respectively. Polyoxin D was found to be a very potent competitive inhibitor with values of the constant of inhibition, Ki' for both species about three orders of magnitude lower than theKm for UDP-GlcNAc. A divalent cation, Mg+2 , Mn+2 or Co+2 , was required for activity. N-acetylglucosamine, the monomer of chitin, stimulated the activity of the enzyme. The crude enzyme preparation of ~ candelabrum, unlike that of ~ pusilla, showed an absolute requirement for both Mg+2 and N-acetylglucosamine. Large differences in response to exogenous proteases were noted in the ratio of active to inactive chitin synthase of the two species. A fifteen fold or greater increase was obtained after treatment with acid protease (from Aspergillussaitoi) as compared to a two- to four-fold activation of the M. pusilla membrane preparation treated similarly. During storage at 4°C over 48 hours, an endogenous activation of chitin synthase of ~ pus ilIa was achieved, comparable to that obtained by exogenous protease treatment. The high speed supernatant of both species inhibited the chitin synthase activity of the mixed membrane fractions. The inhibitor of ~ pus ilIa was effective against the pre-activated enzyme whereas that of M. candelabrum inhibited the activated enzyme. Several possibilities are discussed as to the role of the different factors regulating the enzyme activity. The suggestion is made from the properties of chitin synthase in the two species that in vivo a delicate balance exists between the activation and inactivation of the enzyme which is responsible for the pattern of wall growth of each fungus.
Resumo:
There were three purposes to this study. The first purpose was to determine how learning can be influenced by various factors i~ the rock climbing experience. The second purpose was to examine what people can learn from the rock climbing experience. The third purpose was to investigate whether that learning can transfer from the rock climbing experience to the subjects' real life in the workplace. Ninety employees from a financial corporation in the Niagara Region volunteered for this study. All subjects were surveyed throughout a one-day treatment. Ten were purposefully selected one month later for interviews. Ten themes emerged from the subjects in terms of what was learned. Inspiration, motivation, and determination, preparation, goals and limitations, perceptions and expectations, confidence and risk taking, trust and support, teamwork, feedback and encouragement, learning from failure, and finally, skills and flow. All participants were able to transfer what was learned back to the workplace. The results of this study suggested that subjects' learning was influenced by their ability to: take risks in a safe environment, fail without penalty, support each other, plan without time constraints, and enjoy the company of fellow workers that they wouldn't normally associate with. Future directions for research should include different types of treatments such as white water rafting, sky diving, tall ship sailing, or caving.
Seasonal variation in hatching pattern and chick survival in the ring-billed gull Larus delawarensis
Resumo:
The general objective of my study was to monitor proximate causes and seasonal patterns of hatching asynchrony and chick survival in the Ring-billed Gull (Larus delawarensis). Two different plots were set up at a Ring-billed Gull colony near Port Colborne, Ontario in the summer of 1992. One group was from 'peak' nesting pairs (clutches initiated between 15 April and 1 May); a second group was from 'late' nesting pairs (clutches initiated between 9 .. 22 May). Despite equal intra-clutch egg laying intervals between the peak and late periods, intra-clutch hatching intervals lengthened as the season progressed (ie. hatching became more asynchronous). Clutches from both periods were monitored for nocturnal attendance and brood patch development of parents was monitored during the egg laying period. Late nesters were characterized by an absence of nocturnal desertion, substantial brood patch defeatheration at clutch initiation and a reduction in the number of chicks fledged per pair. Chick survival to 25 days (taken as fledging) reflected patterns of chick mass at brood completion and five days post-brood completion, in peak clutches. In late clutches, survival was poor for all chicks and, was partially independent of hatching order, due in part to stochastic events such as Herring Gull predation and adverse weather. In both the peak and late periods, last-hatched C-chicks realized the poorest survival to fledging among brood mates. An artificial hatching pattern (manipulated synchrony) and an artificial hatching order were created, in three-chick broods, through a series of egg exchanges. In peak and late clutches manipulated to hatch synchronously (s; 24 h): C-chick survival to fledging did not differ from the survival of A- and B-chicks, in the peak period. In the late period, the survival of C-chicks was significantly lower than that of A-chicks. In peak clutches manipulated such that chicks from last-laid eggs (C-chicks) hatched 24 h - 48 h ahead of the A- and B- chicks, C-chick survival was greater than in controls. Within those broods, C-chicks survived better on average than both A- and B- chicks.
Resumo:
There is considerable interest in intramolecular energy transfer, especially in complexes which absorb visible light, because it is crucial to the better understanding of photoharvesting systems in photosynthetic organisms and for utilizing solar energy as well. Porphyrin dimers represent one of the best systems for the exploration of light-induced intramolecular energy transfer. Many kinds of porphyrins and porphyrin dimers have been studied over the past decade, however little attention has been paid to the influence of paramagnetic metals on the behavior of their excited states. In this thesis, Electron Paramagnetic Resonance Spectroscopy (EPR) is used to study such compounds. After light irradiation, porphyrins easily produce a variety of excited states, which are spin polarized and can be detected by the time-resolved (TR) EPR technique. The spin polarized results for vanadyl porphyrins, their electrostatically-coupled dimers, a covalently-linked copper porphyrin-free base porphyrin dimer, and free base porphyrins are presented in this thesis. From these results we can conclude that the spin polarization patterns of vanadyl porphyrins come primarily from the trip-quartet state generated by intersystem crossing (lSC) from the excited sing-doublet state through the trip-doublet state. The spin polarization pattern of electrostatically-coupled vanadyl porphyrin-free base porphyrin dimer is produced by the triplet state of the free base porphyrin half which is coupled to the unpaired electron on the vanadyl ion.
Resumo:
The proce-ss ofoxygenic photosynthesis is vital to life on Earth. the central event in photosynthesis is light induced electron transfer that converts light into energy for growth. Ofparticular significance is the membrane bound multisubunit protein known as Photosystem I (PSI). PSI is a reaction centre that is responsible for the transfer of electrons across the membrane to reduce NADP+ to NADPH. The recent publication ofa high resolution X-ray structure of PSI has shown new information about the structure, in particular the electron transfer cofactors, which allows us to study it in more detail. In PSI, the secondary acceptor is crucial for forward electron transfer. In this thesis, the effect of removing the native acceptor phylloquinone and replacing it with a series of structurally related quinones was investigated via transient electron paramagnetic resonance (EPR) experiments. The orientation of non native quinones in the binding site and their ability to function in the electron transfer process was determined. It was found that PSI will readily accept alkyl naphthoquinones and anthraquinone. Q band EPR experiments revealed that the non-native quinones are incorporated into the binding site with the same orientation of the headgroup as in the native system. X band EPR spectra and deuteration experiments indicate that monosubstituted naphthoquinones are bound to the Al site with their side group in the position occupied by the methyl group in native PSI (meta to the hydrogen bonded carbonyl oxygen). X band EPR experiments show that 2, 3- disubstituted methyl naphthoquinones are also incorporated into the Al site in the same orientation as phylloquinone, even with the presence of a halogen- or sulfur-containing side chain in the position normally occupied by the phytyl tail ofphylloquinone. The exception to this is 2-bromo-3-methyl --.- _. -. - -- - - 4 _._ _ _ - _ _ naphthoquinone which has a poorly resolved spectrum, making determination of the orientation difficuh. All of the non-native quinones studied act as efficient electron acceptors. However, forward electron transfer past the quinone could only be demonstrated for anthraquinone, which has a more negative midpoint potential than phylloquinone. In the case of anthraquinone, an increased rate of forward electron transfer compared to native PSI was found. From these results we can conclude that the rate ofelectron transfer from Al to Fx in native PSI lies in the normal region ofthe Marcus Curve.
Resumo:
Since its discovery nearly a century ago, a-tocopherol (vitamin E) research has been mainly focused on its ability to terminate the cycle of lipid peroxidation in membranes. Nitrobenzoxadiazole fluorescent analogues were made previously to study the intracellular transfer of vitamin E in cells. However, these molecules were reportedly susceptible to photobleaching while under illumination for transfer assays and microscopy. Here is reported the synthesis of a series of fluorescent analogues of vitamin E incorporating the more robust dipyrrometheneboron difluoride fluorophore (BDP-a-Tocs; Aex = 507 nm, Aem = 511 nm). C8-BDP-a-Toc 42c, having an eight-carbon chain between the chromanol and fluorophore, wa<; shown to bind specifically to a-tocopherol transfer protein with a dissociation constant of approximately 100 nM. Another fluorescent analogue of vitamin E with a thienyl derivative of BODIPY that is excited and fluoresces at longer wavelengths (Aex = 561 nm, Aem = 570 nm) is in development.