951 resultados para Structural changes


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PURPOSE: To evaluate the photodynamic potential of a new hydrosoluble photosensitizer (WST-11, Stakel; Steba Biotech, Toussus-Le-Noble, France), for use in occlusion of normal choroidal vessels in the rabbit eye and CNV (choroidal neovascularization) in the rat eye. METHODS: Occlusive and nonocclusive parameters of Stakel and verteporfin photodynamic therapy (PDT) were investigated in pigmented rabbits. Eyes were followed by fluorescein angiography (FA) and histology at various intervals after PDT. RESULTS: When occlusive parameters (fluence of 50 J/cm(2), 5 mg/kg drug dose and DLI [distance to light illumination] of 1 minute) were used, Stakel PDT was efficient immediately after treatment without associated structural damage of the RPE and retina overlying the treated choroid in the rabbit eye. Two days later, total occlusion of the choriocapillaries was seen in 100% of the treated eyes, along with accompanying histologic structural changes in the overlying retina. When the occlusive parameters (fluence, 100 J/cm2; drug dose, 12 mg/m2; and DLI, 5 minutes) of verteporfin PDT were used, occlusion of the choriocapillaries was observed in 89% of the treated eyes. Histology performed immediately after treatment demonstrated structural damage of the overlying retina and RPE layer. Weaker, nonocclusive Stakel PDT parameters (25 J/cm2, 5 mg/kg, and DLI of 10 minutes) did not induce choriocapillary occlusion or retinal lesions on FA or histology. Weaker, nonocclusive verteporfin PDT parameters (10 J/cm2, 0.2 mg/kg, and DLI of 5 minutes) did not induce choriocapillary occlusion. However, histology of these eyes showed the presence of damage in the retinal and choroidal tissues. Moreover, preliminary results indicate that selective CNV occlusion can be achieved with Stakel PDT in the rat eye. CONCLUSIONS: Unlike verteporfin PDT, Stakel PDT does not cause direct damage to the RPE cell layer or retina. These observations indicate that Stakel PDT may have a high potential for beneficial therapeutic outcomes in treatment of AMD.

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In intestinal secretions, secretory IgA (SIgA) plays an important sentinel and protective role in the recognition and clearance of enteric pathogens. In addition to serving as a first line of defense, SIgA and SIgA x antigen immune complexes are selectively transported across Peyer's patches to underlying dendritic cells in the mucosa-associated lymphoid tissue, contributing to immune surveillance and immunomodulation. To explain the unexpected transport of immune complexes in face of the large excess of free SIgA in secretions, we postulated that SIgA experiences structural modifications upon antigen binding. To address this issue, we associated specific polymeric IgA and SIgA with antigens of various sizes and complexity (protein toxin, virus, bacterium). Compared with free antibody, we found modified sensitivity of the three antigens assayed after exposure to proteases from intestinal washes. Antigen binding further impacted on the immunoreactivity toward polyclonal antisera specific for the heavy and light chains of the antibody, as a function of the antigen size. These conformational changes promoted binding of the SIgA-based immune complex compared with the free antibody to cellular receptors (Fc alphaRI and polymeric immunoglobulin receptor) expressed on the surface of premyelocytic and epithelial cell lines. These data reveal that antigen recognition by SIgA triggers structural changes that confer to the antibody enhanced receptor binding properties. This identifies immune complexes as particular structural entities integrating the presence of bound antigens and adds to the known function of immune exclusion and mucus anchoring by SIgA.

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This report is divided into two volumes. This volume (Volume I) summarizes a structural health monitoring (SHM) system that was developed for the Iowa DOT to remotely and continuously monitor fatigue critical bridges (FCB) to aid in the detection of crack formation. The developed FCB SHM system enables bridge owners to remotely monitor FCB for gradual or sudden damage formation. The SHM system utilizes fiber bragg grating (FBG) fiber optic sensors (FOSs) to measure strains at critical locations. The strain-based SHM system is trained with measured performance data to identify typical bridge response when subjected to ambient traffic loads, and that knowledge is used to evaluate newly collected data. At specified intervals, the SHM system autonomously generates evaluation reports that summarize the current behavior of the bridge. The evaluation reports are collected and distributed to the bridge owner for interpretation and decision making. Volume II summarizes the development and demonstration of an autonomous, continuous SHM system that can be used to monitor typical girder bridges. The developed SHM system can be grouped into two main categories: an office component and a field component. The office component is a structural analysis software program that can be used to generate thresholds which are used for identifying isolated events. The field component includes hardware and field monitoring software which performs data processing and evaluation. The hardware system consists of sensors, data acquisition equipment, and a communication system backbone. The field monitoring software has been developed such that, once started, it will operate autonomously with minimal user interaction. In general, the SHM system features two key uses. First, the system can be integrated into an active bridge management system that tracks usage and structural changes. Second, the system helps owners to identify damage and deterioration.

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Pancreatic acinar cells of euthermic, hibernating and arousing individuals of the hazel dormouse Muscardinus avellanarius (Gliridae) have been observed at the electron-microscopic level and analysed by means of ultrastructural morphometry and immunocytochemistry in order to investigate possible fine structural changes of cellular components during periods of strikingly different degrees of metabolic activity. During hibernation, the cisternae of the rough endoplasmic reticulum (RER) flatten assuming a parallel pattern, the Golgi apparatus is extremely reduced and the mitochondria contain many electron-dense particles. The cell nuclei appear irregularly shaped, with deep indentations containing small zymogen granules. They also contain abundant coiled bodies and unusual constituents, such as amorphous bodies and dense granular bodies. Large numbers of zymogen granules occur in all animals. However, the acinar lumina are open and filled with zymogen only in euthermic animals, whereas, in hibernating and arousing individuals, they appear to be closed. Morphometrical analyses indicate that, in pancreatic acinar cells, nuclei and zymogen granules significantly decrease in size from euthermia to hibernation, probably reflecting a drastic decrease of metabolic activities, mainly protein synthesis and processing. In all the studied animals, immunocytochemistry with specific antibodies has revealed an increasing gradient in alpha-amylase content along the RER-Golgi-zymogen granule pathway, reflecting the protein concentration along the secretory pathway. Moreover, during deep hibernation, significantly larger amounts of alpha-amylase accumulate in RER and zymogen granules in comparison to the other seasonal phases analysed. Upon arousal, all cytoplasmic and nuclear constituents restore their euthermic aspect and all morphometrical and immunocytochemical parameters exhibit the euthermic values, thereby indicating a rapid resumption of metabolic activities.

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Angiotensin II can raise blood pressure rapidly by inducing direct vasoconstriction and by activating the sympathetic nervous system via central and peripheral mechanisms. In addition, this peptide may act as a growth factor to cause vascular and cardiac hypertrophy (CVH). The structural changes caused by hypertension can therefore be amplified by angiotensin II. Blockade of angiotensin II generation with angiotensin-converting enzyme (ACE) inhibitors appears to be particularly effective in preventing the development of cardiovascular hypertrophy. This beneficial effect might be related to some extent to local accumulation of bradykinin. ACE is one of the enzymes physiologically involved in bradykinin degradation. Treatment of hypertensive rats with a selective bradykinin antagonist can attenuate the blood pressure-lowering effect of ACE inhibition and render less effective the prevention of intimal thickening after endothelial removal from the rat carotid artery. Bradykinin is a vasodilator that acts by increasing the release of endothelium-derived factors such as nitric oxide and prostacyclin, which may have antiproliferative activity. However, blockade of the renin-angiotensin system with an angiotensin II subtype 1-receptor antagonist is also effective in preventing cardiac hypertrophy and neointimal proliferation after endothelial injury. Therefore, the exact contribution of bradykinin to the beneficial effects of ACE inhibition on cardiovascular hypertrophy remains to be further explored.

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L'article rend compte des résultats d'une recherche comparative sur les processus de féminisation des professions juridiques en France et en Grande-Bretagne. Les auteurs attirent l'attention sur l'importance du rôle du « levier des diplômes » sur la féminisation plus précoce et plus soutenue de certaines professions juridiques en France par rapport à la Grande-Bretagne. Les auteurs situent ce phénomène de féminisation dans le contexte des transformations structurelles qui touchent ces professions depuis le milieu des années 1970. Prenant appui sur les données portant sur l'évolution des carrières des avocats français et des solicitors britanniques en fonction du sexe et de l'ancienneté, elles attirent l'attention sur la manière dont ces transformations structurelles s'articulent avec le phénomène de féminisation et insistent sur la nécessité d'une analyse approfondie des trajectoires professionnelles sexuées dans ce contexte de grands bouleversements structurels. The paper presents the results of a comparative research project on the feminisation of the legal professions in Britain and France. The authors stress the importance of the role of the « qualifications lever » on the earlier and more extensive character of the feminisation of certain legal professions in France as compared to Britain. An attempt is made to place feminisation in the general context of structural change taking place within the legal profesions since the middle of the 1970's. On the basis of original data on the career structure of French avocats and British solicitors by gender and length of service, the authors stress the manner in which such structural changes interrelate with the process of professional féminisation and insist on the need to adopt in-depth analysis of gendered professional career patterns within this context of profound structural transformation

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Background: It has been suggested that chromosomal rearrangements harbor the molecular footprint of the biological phenomena which they induce, in the form, for instance, of changes in the sequence divergence rates of linked genes. So far, all the studies of these potential associations have focused on the relationship between structural changes and the rates of evolution of single-copy DNA and have tried to exclude segmental duplications (SDs). This is paradoxical, since SDs are one of the primary forces driving the evolution of structure and function in our genomes and have been linked not only with novel genes acquiring new functions, but also with overall higher DNA sequence divergence and major chromosomal rearrangements.Results: Here we take the opposite view and focus on SDs. We analyze several of the features of SDs, including the rates of intraspecific divergence between paralogous copies of human SDs and of interspecific divergence between human SDs and chimpanzee DNA. We study how divergence measures relate to chromosomal rearrangements, while considering other factors that affect evolutionary rates in single copy DNA. Conclusion: We find that interspecific SD divergence behaves similarly to divergence of single-copy DNA. In contrast, old and recent paralogous copies of SDs do present different patterns of intraspecific divergence. Also, we show that some relatively recent SDs accumulate in regions that carry inversions in sister lineages.

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Diplomityö tehtiin taustatutkimukseksi Komartek Oyj:n Kolibri-projektiin, jonka tarkoituksena on tuottaa uuden sukupolven asiakastietojärjestelmä sähköyhtiöille. Työn tarkoituksena oli kartoittaa sähkömarkkinoiden liiketoiminnan nykytilaa ja lähitulevaisuutta, kun sähkömarkkinoiden täydellisestä vapautumisesta on kulunut viisi vuotta. Kirjallisuuden perusteella tutkittiin markkinoiden vapautumista ja sähkömarkkinoiden nykyistä tilannetta. Työssä pohdittiin myös nykyisten markkinoiden toimijoitaja heidän toimintakenttäänsä. Toimintakenttää kartoitettiin myös päästökaupan ja hajautetun energiantuotannon kannalta. Diplomityön yhteydessä tehtiin kaksi haastattelututkimusta. Asiantuntijahaastattelu tehtiin 30 alan asiantuntijalle sähköpostitse Delphoi-menetelmällä ja tutkimuksen tarkoitus oli kerätä tietoa sähköyhtiöiden toimintaympäristön luomista uhkista ja mahdollisuuksista. Sähköyhtiöihin tehdyssä haastattelututkimuksessa haastateltiin 13 sähköyhtiön edustajaa. Tutkimuksen tarkoitus oli kartoittaa yhtiöiden tekemiä toimenpiteitä ja strategioita muuttuvassa toimintaympäristössä. Sähkömarkkinoiden rakennemuutos ei ole liiketoiminnan kannalta vielä loppunut. Useat sähköyhtiöt harjoittavat toimintaansa sekä vanhan että uuden tilanteen mukaan. Lisäksi edelleen odotetaan suuria muutoksia toimintakentässä esimerkiksi päästökaupan ja Euroopan sähkömarkkinoiden avaamisen suhteen. Toisaalta sähkömarkkinoidenavaaminen on tuonut toimijoille myös uusia mahdollisuuksia laajentaa tai tehostaa toimintaansa. Sähkömarkkinoiden liiketoiminnasta olisi hyvä tehdä lisäselvityksiä markkinatilanteen vakiinnuttua.

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Pheromones form an essential chemical language of intraspecific communication in many animals. How olfactory systems recognize pheromonal signals with both sensitivity and specificity is not well understood. An important in vivo paradigm for this process is the detection mechanism of the sex pheromone (Z)-11-octadecenyl acetate (cis-vaccenyl acetate [cVA]) in Drosophila melanogaster. cVA-evoked neuronal activation requires a secreted odorant binding protein, LUSH, the CD36-related transmembrane protein SNMP, and the odorant receptor OR67d. Crystallographic analysis has revealed that cVA-bound LUSH is conformationally distinct from apo (unliganded) LUSH. Recombinantly expressed mutant versions of LUSH predicted to enhance or diminish these structural changes produce corresponding alterations in spontaneous and/or cVA-evoked activity when infused into olfactory sensilla, leading to a model in which the ligand for pheromone receptors is not free cVA, but LUSH that is "conformationally activated" upon cVA binding. Here we present evidence that contradicts this model. First, we demonstrate that the same LUSH mutants expressed transgenically affect neither basal nor pheromone-evoked activity. Second, we compare the structures of apo LUSH, cVA/LUSH, and complexes of LUSH with non-pheromonal ligands and find no conformational property of cVA/LUSH that can explain its proposed unique activated state. Finally, we show that high concentrations of cVA can induce neuronal activity in the absence of LUSH, but not SNMP or OR67d. Our findings are not consistent with the model that the cVA/LUSH complex acts as the pheromone ligand, and suggest that pheromone molecules alone directly activate neuronal receptors.

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Tutkielman päätavoitteenaoli analysoida, kuinka raportoitavat segmentit määritetään IAS 14 Segmenttiraportoinnin mukaan. Tutkielma keskittyy yrityskauppojen ja muiden rakenteellisten muutosten vaikutukseen. Lähestymistapa on päätöksentekoa tukeva ja keskittyy teoreettiseen aiheen käsittelyyn sekä omaa normatiivisia piirteitä. Teoriaosuus selittää kansainvälisten tilinpäätösstandardien (IFRS) vaatimukset segmenttiraportoinnille sekä sisältää vertailevan analyysin U.S. GAAP:n vastaavaan segmenttistandardiin SFAS 131:een. Teoriaosuuden johtopäätös on IAS 14:n tärkeys linkkinä johdonraportoinnin ja ulkoisen raportoinnin välillä. Se myös esittää, kuinka IAS 14:n ja SFAS 131:n välillä ei ole merkittäviä eroja. Case-yrityksen raportointiorganisaatio on kompleksi johtuen yrityskaupoista ja muista rakenteellisista muutoksista. Organisaatio tulisi yksinkertaistaa uuden laskentajärjestelmän myötä kattamaan vain juridiset yhtiöt, segmentit ja rahavirtaa tuottavat yksiköt. Loppupäätelmä osoitti yrityksen sisäisen ja ulkoisen raportoinnin olevan identtisiä. Kun organisaatiorakenne muuttuu, raportoitavien segmenttien määrittäminen riippuu johdon näkemyksestä ja siten johdonraportoinnista. Uutena seikkana nousi esille segmenttien määrittämisen mahdollinen syventäminen rahavirtaa tuottavien yksiköiden tasolle.

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The flexibility of different regions of HIV-1 protease was examined by using a database consisting of 73 X-ray structures that differ in terms of sequence, ligands or both. The root-mean-square differences of the backbone for the set of structures were shown to have the same variation with residue number as those obtained from molecular dynamics simulations, normal mode analyses and X-ray B-factors. This supports the idea that observed structural changes provide a measure of the inherent flexibility of the protein, although specific interactions between the protease and the ligand play a secondary role. The results suggest that the potential energy surface of the HIV-1 protease is characterized by many local minima with small energetic differences, some of which are sampled by the different X-ray structures of the HIV-1 protease complexes. Interdomain correlated motions were calculated from the structural fluctuations and the results were also in agreement with molecular dynamics simulations and normal mode analyses. Implications of the results for the drug-resistance engendered by mutations are discussed briefly.

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13-16-vuotiaiden purentaelimistön toimintahäiriöt ja päänsärky Tutkimuksen tarkoituksena oli selvittää purentaelimistön toimintahäiriöihin (TMD) liittyvien oireiden ja kliinisten löydösten esiintyvyyttä ja muutosta kolmen vuoden seurannan aikana päänsärystä kärsivillä nuorilla ja heidän verrokeillaan, TMD-löydösten yhteyttä eri tyyppisiin päänsärkyihin ja päänsärkyyn liittyviin tekijöihin, TMD-löydöksiä ennustavia tekijöitä sekä perhetaustan osuutta TMD-löydösten esiintyvyyteen. Tutkimus perustui kahteen laajaan koululaismateriaaliin Turun seudulla. Ensimmäinen 13-vuotiaiden nuorten ryhmä (n = 311) osallistui myös 16-vuotiaana seuranta-tutkimukseen. Toisen 13-vuotiaiden nuorten ryhmän (n = 154) äidit (n = 154) osallistuivat myös tutkimukseen, jossa selvitettiin tapaus-verrokkiasetelmassa TMD-löydösten ja päänsärkyjen esiintyvyyttä kahdessa sukupolvessa. Nuoret jaettiin päänsärkyryhmiin ja terveisiin kontrolleihin IHS (1988) päänsärky-kriteerien mukaisesti kyselykaavakkeen ja lääkärin suorittaman haastattelun ja kliinisen tutkimuksen antamien tietojen perusteella. Lääkäri määritteli äitien päänsärkydiagnoosin kyselykaavakkeen tietojen perusteella. Kaikki nuoret ja heidän äitinsä haastateltiin ja heille tehtiin kliininen purentafysiologinen tutkimus sokkoutetusti. Tutkimuksen tulokset osoittivat, että tytöillä esiintyi TMD-löydöksiä selvästi enemmän kuin pojilla sekä ennen puberteettia että sen jälkeen. Tutkimuksessa havaittiin selkeä yhteys TMD-löydösten ja molempien päänsärkytyyppien, migreenin ja episodisen tensiotyyppisen päänsäryn, välillä. Kolmen vuoden seurannan aikana TMD-löydöksissä havaittiin runsasta muutosta ja iän myötä vähenemistä, mutta TMD-oireiden kohdalla ei vastaavaa muutosta todettu. TMD-löydösten ja niska-hartiaseudun lihaskipujen välillä havaittiin yhteys 13-vuotiailla nuorilla. Mikään päänsärkyyn liittyvistä tekijöistä 13-vuotiailla ei osoittautunut ennustavaksi taustatekijäksi myöhemmille TMD-löydöksille. TMD-löydösten suhteen ei todettu perheyhteyttä. Päänsäryistä kärsivillä nuorilla on enemmän myös muita kiputiloja, kuten purentaelimistön toimintahäiriöitä ja niska-hartiaseudun kipuja, kuin heidän terveillä verrokeillaan. 1316 vuoden iässä nämä löydökset ovat valtaosaltaan lieviä ja vaihtelevia.

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NR2E3 encodes the photoreceptor-specific nuclear hormone receptor that acts as a repressor of cone-specific gene expression in rod photoreceptors, and as an activator of several rod-specific genes. Recessive variants located in the ligand-binding domain (LBD) of NR2E3 cause enhanced short wavelength sensitive- (S-) cone syndrome (ESCS), a retinal degeneration characterized by an excess of S-cones and non-functional rods. We analyzed the dimerization properties of NR2E3 and the effect of disease-causing LBD missense variants by bioluminescence resonance energy transfer (BRET(2) ) protein interaction assays. Homodimerization was not affected in presence of p.A256V, p.R039G, p.R311Q, and p.R334G variants, but abolished in presence of p.L263P, p.L336P, p.L353V, p.R385P, and p.M407K variants. Homology modeling predicted structural changes induced by NR2E3 LBD variants. NR2E3 LBD variants did not affect interaction with CRX, but with NRL and rev-erbα/NR1D1. CRX and NRL heterodimerized more efficiently together, than did either with NR2E3. NR2E3 did not heterodimerize with TLX/NR2E1 and RXRα/NR2C1. The identification of a new compound heterozygous patient with detectable rod function, who expressed solely the p.A256V variant protein, suggests a correlation between LBD variants able to form functional NR2E3 dimers and atypical mild forms of ESCS with residual rod function.

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We have studied the effect of pressure on the structural and vibrational properties of lanthanum tritungstate La2(WO4)3. This compound crystallizes under ambient conditions in the modulated scheelite-type structure known as the α phase. We have performed x-ray diffraction and Raman scattering measurements up to a pressure of 20 GPa, as well as ab initio calculations within the framework of the density functional theory. Up to 5 GPa, the three methods provide a similar picture of the evolution under pressure of α-La2(WO4)3. At 5 GPa, we begin to observe some structural changes, and above 6 GPa we find that the x-ray patterns cannot be indexed as a single phase. However, we find that a mixture of two phases with C2/c symmetry accounts for all diffraction peaks. Our ab initio study confirms the existence of several C2/c structures, which are very close in energy in this compression range. According to our measurements, a state with medium-range order appears at pressures above 9 and 11 GPa, from x-ray diffraction and Raman experiments, respectively. Based upon our theoretical calculations we propose several high-pressure candidates with high cationic coordinations at these pressures. The compound evolves into a partially amorphous phase at pressures above 20 GPa.

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This paper analyses how banking regulation was introduced in Switzerland - one of the world's most prominent financial centres - which remained in place until the beginning of the twenty-first century. It shows that the law adopted on 8 November 1934 is a perfect example of capture of the regulator by the regulated. Essentially a political response in the context of the economic crisis of the 1930s, it largely reflected the interests of banking circles by limiting the intervention of the State as much as possible. The introduction of the new legislation was facilitated by the temporary weakness of Swiss banking circles, as they depended on the State to delay or prevent the collapse of many major credit institutions. They did not manage to derail the law as they had two decades earlier when they scuppered the federal bill on banks drawn up between 1914 and 1916. But this time they were better organized and more united, and intervened all the more effectively in the legislative process itself. The 1934 law is thus distinctive in that it made no structural changes to the architecture of the financial centre but merely codified its practices through flexible legislation meant to reassure the public. The law was aimed less at controlling banking activity than at keeping - thanks to skilfully calibrated political concessions - the State from having to intervene more directly in the internal management of banks or in the fixing of interest rates and the export of capital.