947 resultados para Bilayer Segmentation


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This study applied qualitative case study method for solving what kind of benefits salespeople and their customers perceived to gain when sales reps used a specific sales force automation tool, that defined the values and identified segment that best fit to each customer. The data consisting of four interviews was collected using semi-structured individual method and analyzed with thematic analysis technique. The analysis revealed five salespeople perceived benefits and four customer perceived benefits. Salespeople perceived benefits were improvements in customer knowledge, guidance of sales operations, salesperson-customer relationship building, time management and growing performance. Customer perceived benefits were information transmission, improved customer service, customer-salesperson relationship building and development of operations, which of the last was found as a new previously unrecognized customer benefit.

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Most cells exchange ions and small metabolites via gap junction channels. These channels are made of two hemichannels (connexons), each formed by the radial arrangement of six connexin (Cx) proteins. Connexins span the bilayer four times (M1-M4) and have both amino- and carboxy-termini (NT, CT) at the cytoplasmic side of the membrane, forming two extracellular loops (E1, E2) and one inner (IL) loop. The channels are regulated by gates that close with cytosolic acidification (e.g., CO2 treatment) or increased calcium concentration, possibly via calmodulin activation. Although gap junction regulation is still unclear, connexin domains involved in gating are being defined. We have recently focused on the CO2 gating sensitivity of Cx32, Cx38 and various mutants and chimeras expressed in Xenopus oocytes and studied by double voltage clamp. Cx32 is weakly sensitive to CO2, whereas Cx38 is highly sensitive. A Cx32 chimera containing the second half of the inner loop (IL2) of Cx38 was as sensitive to CO2 as Cx38, indicating that this domain plays an important role. Deletion of CT by 84% did not affect CO2 sensitivity, but replacement of 5 arginines (R) with sparagines (N) at the beginning of CT (C1) greatly enhanced the CO2 sensitivity of Cx32. This suggests that whereas most of CT is irrelevant, positive charges of C1 maintain the CO2 sensitivity of Cx32 low. As a hypothesis we have proposed a model that involves charge interaction between negative residues of the beginning of IL1 and positive residues of either C1 or IL2. Open and closed channels would result from IL1-C1 and IL1-IL2 interactions, respectively

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Alpha-Hemolysin is synthesized as a 1024-amino acid polypeptide, then intracellularly activated by specific fatty acylation. A second activation step takes place in the extracellular medium through binding of Ca2+ ions. Even in the absence of fatty acids and Ca2+ HlyA is an amphipathic protein, with a tendency to self-aggregation. However, Ca2+-binding appears to expose hydrophobic patches on the protein surface, facilitating both self-aggregation and irreversible insertion into membranes. The protein may somehow bind membranes in the absence of divalent cations, but only when Ca2+ (or Sr2+, or Ba2+) is bound to the toxin in aqueous suspensions, i.e., prior to its interaction with bilayers, can a-hemolysin bind irreversibly model or cell membranes in such a way that the integrity of the membrane barrier is lost, and cell or vesicle leakage ensues. Leakage is not due to the formation of proteinaceous pores, but rather to the transient disruption of the bilayer, due to the protein insertion into the outer membrane monolayer, and subsequent perturbations in the bilayer lateral tension. Protein or glycoprotein receptors for a-hemolysin may exist on the cell surface, but the toxin is also active on pure lipid bilayers.

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Liposomes (lipid-based vesicles) have been widely studied as drug delivery systems due to their relative safety, their structural versatility concerning size, composition and bilayer fluidity, and their ability to incorporate almost any molecule regardless of its structure. Liposomes are successful in inducing potent in vivo immunity to incorporated antigens and are now being employed in numerous immunization procedures. This is a brief overview of the structural, biophysical and pharmacological properties of liposomes and of the current strategies in the design of liposomes as vaccine delivery systems.

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The primary purpose of this research is to develop an enhanced understanding of how consumption values influence environmentally responsible consumption of print and digital media. Theoretical elaboration considers the associations of functional, social and emotional consumption values, green consumer segmentation and media consumption. Additionally, the purpose is to identify consumer perceptions of print and digital media’s environmental responsibility. Empirical analysis was based on qualitative interviews with a sample of 20 Finnish consumers categorized in two segments: young adults and middle aged consumers. Primary data collection was conducted through individual, semi-structured interviews. To analyze the respondents’ approach on the topic, the interviews disclosed themes of media consumption, perceived environmental friendliness of media, norms of behavior and consumers’ general consumption patterns. The results implicate functional value dominated the consumption decision-making process both in a general level and in media consumption. In addition to functional value, environmental responsibility does provide consumers with both emotional and social values. Analysis on perceived environmental responsibility of media demonstrated consumers generally perceive digital media as an environmentally responsible alternative because it does not create physical paper waste. Nevertheless, the perceptions of environmental responsibility and media consumption patterns lacked a consistent connection. Though, both theory and empirical results indicated an average consumer lacks a comprehensive understanding of digital and print media’s life-cycle and hence their environmental advantages and disadvantages.

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Alzheimer’s disease (AD) is the most common form of dementia. Characteristic changes in an AD brain are the formation of β-amyloid protein (Aβ) plaques and neurofibrillary tangles, though other alterations in the brain have also been connected to AD. No cure is available for AD and it is one of the leading causes of death among the elderly in developed countries. Liposomes are biocompatible and biodegradable spherical phospholipid bilayer vesicles that can enclose various compounds. Several functional groups can be attached on the surface of liposomes in order to achieve long-circulating target-specific liposomes. Liposomes can be utilized as drug carriers and vehicles for imaging agents. Positron emission tomography (PET) is a non-invasive imaging method to study biological processes in living organisms. In this study using nucleophilic 18F-labeling synthesis, various synthesis approaches and leaving groups for novel PET imaging tracers have been developed to target AD pathology in the brain. The tracers were the thioflavin derivative [18F]flutemetamol, curcumin derivative [18F]treg-curcumin, and functionalized [18F]nanoliposomes, which all target Aβ in the AD brain. These tracers were evaluated using transgenic AD mouse models. In addition, 18F-labeling synthesis was developed for a tracer targeting the S1P3 receptor. The chosen 18F-fluorination strategy had an effect on the radiochemical yield and specific activity of the tracers. [18F]Treg-curcumin and functionalized [18F]nanoliposomes had low uptake in AD mouse brain, whereas [18F]flutemetamol exhibited the appropriate properties for preclinical Aβ-imaging. All of these tracers can be utilized in studies of the pathology and treatment of AD and related diseases.

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The effect of the skin secretion of the amphibian Siphonops paulensis was investigated by monitoring the changes in conductance of an artificial planar lipid bilayer. Skin secretion was obtained by exposure of the animals to ether-saturated air, and then rinsing the animals with distilled water. Artificial lipid bilayers were obtained by spreading a solution of azolectin over an aperture of a Delrin cup inserted into a cut-away polyvinyl chloride block. In 9 of 12 experiments, the addition of the skin secretion to lipid bilayers displayed voltage-dependent channels with average unitary conductance of 258 ± 41.67 pS, rather than nonspecific changes in bilayer conductance. These channels were not sensitive to 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid or tetraethylammonium ion, but the experimental protocol used does not permit us to specify their characteristics.

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The photophysical properties of zinc phthalocyanine (ZnPC) and chloroaluminum phthalocyanine (AlPHCl) incorporated into liposomes of dimyristoyl phosphatidylcholine in the presence and absence of additives such as cholesterol or cardiolipin were studied by time-resolved fluorescence, laser flash photolysis and steady-state techniques. The absorbance of the drugs changed linearly with drug concentration, at least up to 5.0 µM in homogeneous and heterogeneous media, indicating that aggregation did not occur in these media within this concentration range. The incorporation of the drugs into liposomes increases the dimerization constant by one order of magnitude (for ZnPC, 3.6 x 10(4) to 1.0 x 10(5) M-1 and for AlPHCl, 3.7 x 10(4) to 1.5 x 10(5) M-1), but this feature dose does not rule out the use of this carrier, since the incorporation of these hydrophobic drugs into liposomes permits their systemic administration. Probe location in biological membranes and predominant positions of the phthalocyanines in liposomes were inferred on the basis of their fluorescence and triplet state properties. Both phthalocyanines are preferentially distributed in the internal regions of the liposome bilayer. The additives affect the distribution of these drugs within the liposomes, a fact that controls their delivery when both are used in a biological medium, retarding their release. The addition of the additives to the liposomes increases the internalization of phthalocyanines. The interaction of the drugs with a plasma protein, bovine serum albumin, was examined quantitatively by the fluorescence technique. The results show that when the drugs were incorporated into small unilamellar liposomes, the association with albumin was enhanced when compared with organic media, a fact that should increase the selectivity of tumor targeting by these phthalocyanines (for ZnPC, 0.71 x 10(6) to 1.30 x 10(7) M-1 and for AlPHCl, 4.86 x 10(7) to 3.10 x 10(8) M-1).

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Pro gradu –tutkielman tavoitteena on tutkia asiakasarvoa ja sitä, miten asiakasarvoa voidaan käyttää hyväksi uusasiakashankinnassa. Tällä hetkellä kirjallisuudessa on pinnalla muutos tuotekeskeisyydestä asiakaskeskeiseen näkökulmaan, joka tunnistaa asiakasarvon tärkeyden bisnes suhteissa. Tämä tutkimus osallistuu kyseiseen keskusteluun muodostamalla tavan mitata asiakasarvoa, ja peilaamalla saavutettuja tuloksia uusasiakashankinta prosessiin. Empiirinen tutkimus on toteutettu kahdessa osassa: kvalitatiivisessa sekä kvantitatiivisessa. Ensimmäisessä osassa haastateltiin kahdeksaa potentiaalista asiakasta, minkä jälkeen saadut tulokset vietiin suurempaan skaalaan toteuttamalla kysely suurelle joukolle potentiaalisia asiakkaita. Lopulliset tulokset osoittavat, että asiakasarvon käyttäminen hyväksi uusasiakashankinnassa on erittäin tehokas ja käyttökelpoinen metodi. Asiakasarvoon perustuvat asiakassegmentit mahdollistavat oikeiden arvojen kommunikoinnin oikeille segmenteille. Se antaa yritykselle myös mahdollisuuden valita houkuttelevimmat asiakasryhmät ja vahvistaa asiakaskantaansa.

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Plants used in traditional medicine are rich sources of hemolysins and cytolysins, which are potential bactericidal and anticancer drugs. The present study demonstrates for the first time the presence of a hemolysin in the leaves of Passiflora quadrangularis L. This hemolysin is heat stable, resistant to trypsin treatment, has the capacity to froth, and acts very rapidly. The hemolysin activity is dose-dependent, with a slope greater than 1 in a double-logarithmic plot. Polyethylene glycols of high molecular weight were able to reduce the rate of hemolysis, while liposomes containing cholesterol completely inhibited it. In contrast, liposomes containing phosphatidylcholine were ineffective. The Passiflora hemolysin markedly increased the conductance of planar lipid bilayers containing cholesterol but was ineffective in cholesterol-free bilayers. Successive extraction of the crude hemolysin with n-hexane, chloroform, ethyl acetate, and n-butanol resulted in a 10-fold purification, with the hemolytic activity being recovered in the n-butanol fraction. The data suggest that membrane cholesterol is the primary target for this hemolysin and that several hemolysin molecules form a large transmembrane water pore. The properties of the Passiflora hemolysin, such as its frothing ability, positive color reaction with vanillin, selective extraction with n-butanol, HPLC profile, cholesterol-dependent membrane susceptibility, formation of a stable complex with cholesterol, and rapid erythrocyte lysis kinetics indicate that it is probably a saponin.

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The brewing and baking yeast Saccharomyces cerevisiae has been used as a model for stress response studies of eukaryotic cells. In this review we focus on the effect of high hydrostatic pressure (HHP) on S. cerevisiae. HHP exerts a broad effect on yeast cells characteristic of common stresses, mainly associated with protein alteration and lipid bilayer phase transition. Like most stresses, pressure induces cell cycle arrest. Below 50 MPa (500 atm) yeast cell morphology is unaffected whereas above 220 MPa wild-type cells are killed. S. cerevisiae cells can acquire barotolerance if they are pretreated with a sublethal stress due to temperature, ethanol, hydrogen peroxide, or pressure. Nevertheless, pressure only leads to protection against severe stress if, after pressure pretreatment, the cells are also re-incubated at room pressure. We attribute this effect to the inhibition of the protein synthesis apparatus under HHP. The global genome expression analysis of S. cerevisiae cells submitted to HHP revealed a stress response profile. The majority of the up-regulated genes are involved in stress defense and carbohydrate metabolism while most repressed genes belong to the cell cycle progression and protein synthesis categories. However, the signaling pathway involved in the pressure response is still to be elucidated. Nitric oxide, a signaling molecule involved in the regulation of a large number of cellular functions, confers baroprotection. Furthermore, S. cerevisiae cells in the early exponential phase submitted to 50-MPa pressure show induction of the expression level of the nitric oxide synthase inducible isoform. As pressure becomes an important biotechnological tool, studies concerning this kind of stress in microorganisms are imperative.

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SStrong evidence suggests that the climate is changing and that these changes are largely caused by human activities. A consensus exists among researchers that human activity is causing global warming and that actions to mitigate global warming need to be taken swiftly. The transportation sector, which relies heavily on fossil fuel burning and primarily oil, is one of the big contributors to air pollution problems at local, regional and global levels. It is the fastest growing source of greenhouse gas emissions and is estimated to be responsible for nearly a quarter of global energyrelated carbon dioxide emissions. Car sharing is a mobility solution encouraging its users to decrease private car usage in favour of communal transit and environmental goals. The idea of car sharing originates from the aspiration to decrease personal car ownership and to reduce vehicle distance travelled. This thesis seeks to complement the understanding of Finnish car sharing users and their usage through better categorization. Through better categorization and segmentation of Finnish car sharing users the thesis seeks to provide information for improved marketing insight. Research is done on the demographic and behavioural characteristics of Finnish car sharing users and they are compared with international findings about the characteristics of International car sharing users. The main research problem is Are Finnish car sharing users similar to international ones? A theoretical research framework on the determinants of individual car sharing usage is built based on international research about demographic and behaviouristic characteristics. After this a quantitative survey is performed to the customers of a Finnish car sharing organization. The data analysed in the thesis consist out of 532 answers received from the car sharing organizations customers. The data is analysed with descriptive and other exploratory methods, which create an understanding of Finnish car sharing users. At the end of the analysis the demographic and behavioural characteristics of Finnish car sharing users are compared with international ones. The research findings of the thesis indicate that the demographic and behavioural characteristics of Finnish car sharing usage largely follow those of their international counterparts. Thanks to the thesis results the car sharing organization is able to better target their customers through improved marketing insight.

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The Saimaa ringed seal is one of the most endangered seals in the world. It is a symbol of Lake Saimaa and a lot of effort have been applied to save it. Traditional methods of seal monitoring include capturing the animals and installing sensors on their bodies. These invasive methods for identifying can be painful and affect the behavior of the animals. Automatic identification of seals using computer vision provides a more humane method for the monitoring. This Master's thesis focuses on automatic image-based identification of the Saimaa ringed seals. This consists of detection and segmentation of a seal in an image, analysis of its ring patterns, and identification of the detected seal based on the features of the ring patterns. The proposed algorithm is evaluated with a dataset of 131 individual seals. Based on the experiments with 363 images, 81\% of the images were successfully segmented automatically. Furthermore, a new approach for interactive identification of Saimaa ringed seals is proposed. The results of this research are a starting point for future research in the topic of seal photo-identification.

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Arvoverkostojen välinen kilpailu nykyisessä liiketoiminnassa on johtanut siihen, että toimittajaportfolioita pyritään hallitsemaan yhä strategisemmin. Yksi tapa hallita yrityksen toimittajaportfoliota on segmentoida toimittajat eri kategorioihin ja asettaa näille kategorioille strategiset tavoitteet. Segmentoinnin työkaluina voidaan käyttää ostoportfolioita, joita on suunniteltu useita erilaisia erilaisiin tarpeisiin. Käytetyin portfoliomalli on Kraljicin ostoportfolio, jota käytetään visualisoimaan yrityksen toimittajia ja tuotteita niiden tuottovaikutuksen ja toimitusriskin perusteella. Tutkimuksen tavoite oli ymmärtää, miten hankinta-alan asiantuntijat hallitsevat toimittajaportfoliotaan, painottaen erityisesti sitä, miten hankinta-asiantuntijat käyttävät tieteellisiä ostoportfolioita todellisessa liike-elämässä. Tutkimus toteutettiin laadullisin menetelmin, koska työn tarkoituksena oli ymmärtää syvällisesti tutkittavia kohteita ja pohtia niitä taustatekijöitä, jotka puoltavat tai hidastavat ostoportfolioiden käyttöä yrityksissä. Työssä haastateltiin viittä hankinta-alan asiantuntijaa, joista kaksi työskentelee johtavissa tehtävissä yksityisessä osakeyhtiössä ja kolme työskentelee johtavissa tehtävissä julkisessa osakeyhtiössä. Työn lopputuloksena voidaan todeta, että Kraljicin ostoportfoliota käytetään laajasti erilaisissa hankinnoissa, mutta muita tieteellisiä malleja ei käytetä. Portfolionanalyysin käyttö liittyy usein hankintaosaston kokoon, hankintahenkilöstön asiantuntevuuteen ja koulutukseen, strategisuuteen ja strategiseen vaikutusvaltaan yrityksessä. Niiden käyttö riippuu myös siitä, minkälaisia hankintoja tehdään. Haastavimmaksi ostoportfolioiden käyttö koetaan palveluiden hankinnoissa. Portfoliomallia hyödynnetään erityisesti, kun yritys kartoittaa toimittajakenttäänsä hakiessaan uusia muutossuuntia liiketoimintaansa.

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Multiple cell membrane alterations have been reported to be the cause of various forms of hypertension. The present study focuses on the lipid portion of the membranes, characterizing the microviscosity of membranes reconstituted with lipids extracted from the aorta and mesenteric arteries of spontaneously hypertensive (SHR) and normotensive control rat strains (WKY and NWR). Membrane-incorporated phospholipid spin labels were used to monitor the bilayer structure at different depths. The packing of lipids extracted from both aorta and mesenteric arteries of normotensive and hypertensive rats was similar. Lipid extract analysis showed similar phospholipid composition for all membranes. However, cholesterol content was lower in SHR arteries than in normotensive animal arteries. These findings contrast with the fact that the SHR aorta is hyporeactive while the SHR mesenteric artery is hyperreactive to vasopressor agents when compared to the vessels of normotensive animal strains. Hence, factors other than microviscosity of bulk lipids contribute to the vascular smooth muscle reactivity and hypertension of SHR. The excess cholesterol in the arteries of normotensive animal strains apparently is not dissolved in bulk lipids and is not directly related to vascular reactivity since it is present in both the aorta and mesenteric arteries. The lower cholesterol concentrations in SHR arteries may in fact result from metabolic differences due to the hypertensive state or to genes that co-segregate with those that determine hypertension during the process of strain selection.