977 resultados para Apoliporotein AI


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Boc-Trp-Ile-Ala-Aib-Ile-Val-Aib-Leu-Aib- Pro-Ala-Aib-Pro-Aib-Pro-Phe-OM(we here Boc is t-butoxycarbonyla nd Aib is a-aminoisobutyriac cid), a synthetica polar analog of the membrane-activefu ngal peptide antibioticz ervamtycinII A, crystallizesi n spaceg roupP 1 withZ =1 and cell parameters a = 9.086 ?0.002 A, b = 10.410 ?+ 0.002 A, c = 28.188 ? 0.004 A, a = 86.13 ? 0.01?, 13 = 87.90 ? 0.01?, and y = 89.27 ? 0.01?;o veralla greementf actorR = 7.3% for 7180 data (Fo > 3cr) and 0.91-A resolution. The peptide backbone makes a continuous spiral that begins as a 310-helix at the N-terminus, changes to an a-helix for two turns, and ends in a spiral of three fl-bends in a ribbon. Each of the fl-bends contains a proline residue at one of the corners. The torsion angles 4i range from -51? to -91? (average value -64o), and the torsion angles ai range from -1? to -46? (average value -31?). There are 10 intramolecularN H...OCh ydrogenb onds in the helix and two directh ead-to-taihl ydrogenb ondsb etween successive molecules. Two H20 and two CH30H solvent molecules fill additional space with appropriate hydrogen bonding in the head-to-tail region, and two additional H20 molecules form hydrogen bonds with carbonyl oxygens near the curve in the helix at Pro-10. Since there is only one peptide molecule per cell in space group P1, the molecules repeat only by translation, and consequently the helices pack parallel to each other.

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Biomimetics involves transfer from one or more biological examples to a technical system. This study addresses four questions. What are the essential steps in a biomimetic process? What is transferred? How can the transferred knowledge be structured in a way useful for biologists and engineers? Which guidelines can be given to support transfer in biomimetic design processes? In order to identify the essential steps involved in carrying out biomimetics, several procedures found in the literature were summarized, and four essential steps that are common across these procedures were identified. For identification of mechanisms for transfer, 20 biomimetic examples were collected and modeled according to a model. of causality called the SAPPhIRE model. These examples were then analyzed for identifying the underlying similarity between each biological and corresponding analogue technical system. Based on the SAPPhIRE model, four levels of abstraction at which transfer takes place were identified. Taking into account similarity, the biomimetic examples were assigned to the appropriate levels of abstraction of transfer. Based on the essential steps and the levels of transfer, guidelines for supporting transfer in biomimetic design were proposed and evaluated using design experiments. The 20 biological and analogue technical systems that were analyzed were similar in the physical effects used and at the most abstract levels of description of their functionality, but they were the least similar at the lowest levels of abstraction: the parts involved. Transfer most often was carried out at the physical effect level of abstraction. Compared to a generic set of guidelines based on the literature, the proposed guidelines improved design performance by about 60%. Further, the SAPPhIRE model turned out to be a useful representation for modeling complex biological systems and their functionality. Databases of biological systems, which are structured using the SAPPhIRE model, have the potential to aid biomimetic concept generation.

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Reactions of [PdIVB-(AI)2]++ [PdIICl4]-- (i) B-(AI)2 = dianion of N,N'-ethylene-/i-propylene-/n-propylene-bis(acetyl-acetoneimine) with some π-acceptor ligands, aliphatic primary amines and nitrosating reagents have been investigated. In all these reactions except nitrosation, 1:1 adducts having the formula, [PdIVB-(AI)2.X] [PdIICl4] [X = triphenylphosphine (TPP), triphenylarsine (TPA), pyridine (Py), methylamine (CH3NH2) or ethylamine (C2H5NH2)] are obtained. The formation of these complexes is associated with a bond isomerization - from Pd-Cxo-π -allylic bond prevailing in [PdIVB-(AI)2]2+ to PdIV-O bonding.Reaction of (i) with nitrosating reagents reduces PdIV to PdII and subsequently transform the γ-CH group, into an ambidentate isonitroso group (°C = NOH). The latter enters into coordination with PdII by dislodging the already coordinated carbonyl group. Further, selective nitrosation (mono- and dinitrosation) has been carried out by controlling the amount of the nitrosating reagent and the reaction time. The complexes have been characterized by elemental analyses, electrical conductivity, magnetic susceptibility and ir spectral data.

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In a max-min LP, the objective is to maximise ω subject to Ax ≤ 1, Cx ≥ ω1, and x ≥ 0. In a min-max LP, the objective is to minimise ρ subject to Ax ≤ ρ1, Cx ≥ 1, and x ≥ 0. The matrices A and C are nonnegative and sparse: each row ai of A has at most ΔI positive elements, and each row ck of C has at most ΔK positive elements. We study the approximability of max-min LPs and min-max LPs in a distributed setting; in particular, we focus on local algorithms (constant-time distributed algorithms). We show that for any ΔI ≥ 2, ΔK ≥ 2, and ε > 0 there exists a local algorithm that achieves the approximation ratio ΔI (1 − 1/ΔK) + ε. We also show that this result is the best possible: no local algorithm can achieve the approximation ratio ΔI (1 − 1/ΔK) for any ΔI ≥ 2 and ΔK ≥ 2.

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Maintenance of breeding efficiency and high semen quality is essential for reproductive success in farm animals. Early recognition of possible inheritable factors causing infertility requires constant attention. This thesis focuses on describing different manifestations of impaired spermatogenesis, their impact on fertility and partly also their incidence in populations. The reasons for spermatogenic failure are various. An interruption of germ cell differentiation, spermatogenic arrest, can lead to infertility. The incidence of azoospermia was investigated in the 1996 2005 survey of Finnish AI and farm breeding boars. We focused on the diagnosis, testicular morphometry and the possible reasons for the condition. The incidence of azoospermia was significantly higher in Yorkshire boars than in the Landrace breed. The most common diagnosis in Yorkshire boars was germ cell arrest at the primary spermatocyte level. The second most frequent diagnosis in Yorkshire boars was segmental aplasia of the Wolffian ducts with idiopathic epididymal obstruction. Other reasons for azoospermia were infrequent. In the second study we investigated the incidence of two relatively well-defined specific sperm defects in Finnish Yorkshire and Landrace boars during the same survey, the immotile short-tail sperm (ISTS) defect and the knobbed acrosome (KA) defect. In the Finnish Yorkshire boars the inherited ISTS defect, and the probably inherited KA defect, were important causes of infertility during 1996 2005. The ISTS defect was found in 7.6% and the KA defect in 0.8% of the Yorkshire boars. No Landrace boars were diagnosed with either of these two defects. In the third study we described a new sterilizing sperm defect in an oligoasthenoterazoospermic bull. Because of its morphological characteristics this defect was termed the multinuclear-multiflagellar sperm (MNMFS) defect. The number of Sertoli cells in the seminiferous tubuli was highly increased in the MNMFS bull compared with the number in normal bulls. In the following two studies we used a combined approach of fluorescence in situ hybridization (FISH), flow cytometry and morphometric studies to provide information on the cytogenetic background of macrocephalic bull spermatozoa. We described cellular features of diploid spermatozoa and compared the failures in the first and second meiotic divisions. In the last study we describe how the transplantation of testicular cells was used to determine whether spermatogonia derived from donor animals are able to colonize and produce motile spermatozoa in immune-competent unrelated boars suffering the ISTS defect. Transplantation resulted in complete focal spermatogenesis, indicated by the appearance of motile spermatozoa and confirmed by genotyping.

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Tutkielmassa tarkastellaan erään 16- ja 17-vuotiaista syntyperäisistä pyhäjärvisistä nuorista tytöistä ja pojista koostuvan sosiaalisen ryhmän puhekieltä diftongin reduktion ja geminaatioilmiöiden kautta. Geminaatioilmiöistä tarkastellaan yleisgeminaatiota ja itämurteiden erikoisgeminaatiota mutta pääpaino on itämurteiden erikoisgeminaatiossa. Tutkimuspaikkakunta Pyhäjärvi sijaitsee maantieteellisesti Pohjois-Pohjanmaalla mutta kuuluu lingvistisesti savolaismurteisiin. Tutkielman tavoitteena on selvittää, kuinka elinvoimaisia tarkasteltavaksi valitut piirteet ovat sekä kuinka paljon ja miten ne varioivat ryhmän puhekielessä. Aineistoa analysoidaan pääasiassa kvantitatiivisesti. Kvalitatiivisesti piirteiden käyttöä tarkastellaan etenkin vuorovaikutuksen mutta myös sukupuolen näkökulmasta. Tutkittavia kielenoppaita on kuusi: kolme tyttöä ja kolme poikaa. Tytöt ovat lukio- ja pojat ammattikouluopiskelijoita. Kielenoppaiden muodostama ryhmä pohjautuu yläkouluaikaisiin ystävyyssuhteisiin ja oli jo olemassa ennen aineistonkeruuta. Tutkielman aineistona on 5 tuntia ryhmän jäsenten välisiä keskusteluja: 2,5 tuntia tyttöjen keskistä keskustelua, 1,5 tuntia poikien keskustelua ja 1 tunti keskustelua, jossa kaikki ryhmän jäsenet olivat läsnä koko ryhmän kesken. Kukin keskustelu on tallennettu sekä ääni- että videonauhalle. Nauhoitukset on tehty maalis- ja toukokuussa 2010. Tutkielman kvantitatiivinen analyysi perustuu korvakuulolla tehtyihin mittauksiin ja niihin perustuviin absoluuttisiin frekvensseihin. Sekä diftongin reduktio että molemmat geminaatioilmiöt ovat ryhmän puhekielessä elinvoimaisia piirteitä, joskin diftongin reduktion kohdalla esiintyminen on labiilia. Etenkin yleisgeminaatio on ryhmän puhekielessä, myös idiolekteittain katsottuna, taajaan esiintyvä ja lähes varioimaton piirre: geminoituminen esiintyy täysgeminaattana lähes aina yleisgeminaation sallivissa konteksteissa. Geminoituminen on vahvempaa ensi- kuin jälkitavuissa. Sen sijaan sekä diftongin reduktio että itämurteiden erikoisgeminaatio varioivat ryhmän puhekielessä yleiskielisten ja eriasteisten murteellisten varianttien välillä. Suurin osa diftongeista, niin i-, u- kuin y-loppuisistakin, esiintyy yleiskielisessä muodossa ja redusoituessaan reduktion lievässä asteessa. Itämurteiden erikoisgeminaation mahdollistavissa konteksteissa yleiskielisiä variantteja on niin ikään murrevariantteja enemmän. Murrevarianttien enemmistö on täysgeminaatallisia. Tutkielmassa selviää lisäksi, että eri diftongien ja konsonanttien välillä on ryhmän puhekielessä eroja sekä piirteiden asteittaisessa että määrällisessä esiintymisessä, samoin kuin eri äänneympäristöissä esiintymisessäkin. Myös idiolektien välillä on eroja diftongin reduktion ja itämurteiden erikoisgeminaation esiintymisessä. Aineisto osoittaa, että sekä diftongin reduktion että itämurteiden erikoisgeminaation esiintymisessä on selviä leksikaalisia rajoitteita kielenoppaiden puheessa. Kun diftongi ai tai ei muodostaa lekseemin yksin (ai dialogipartikkelina ja ei kieltosanana), se on yleiskielinen. Diftongi äi puolestaan esiintyy poikkeuksellisen vahvana varianttina affektisissa yhteyksissä lekseemissä äiti. Affektisuus vaikuttaa liittyvän myös konsonanttiyhtymien lj, rp ja rv jälkikomponenttien geminoitumiseen vahvistavasti lekseemeissä kaljaa, turpaan ja hirvee. Tarkasteluun valittujen puhekielen piirteiden esiintymisessä voi havaita säännönmukaisuutta myös lauserakennetta ja kielenkäyttöä laajemmin tarkastelemalla. Referoinnin ja tarinankerronnan yhteydessä diftongin reduktion ja itämurteiden erikoisgeminaation käyttö yleistyy ja vahvistuu. Vahvistuminen on puhetilanteen ja keskusteluun osallistuvien vuorovaikutustehtävien motivoimaa. Tällöin on kyse selvästä murteella tyylittelystä. Itsekorjauksen ja liitepartikkelin -kO avulla muodostettujen kysymysten yhteydessä piirteet puolestaan esiintyvät aineistossa yleiskielisinä. Yleisgeminaatioon edellä mainitut eivät näytä vaikuttavan. Sukupuolten välillä on huomattavissa eroja tarkasteltujen kielenpiirteiden esiintymisessä ja käytössä. Tutkielma osoittaa, että pojat ovat tarkasteluun valittujen kielenpiirteiden valossa jonkin verran tyttöjä murteellisempia. Sukupuolten välisiä murteellisuuseroja voidaan selittää etenkin opiskelupaikkakunnan, koulutuksen, sosiaalisten kontaktien, kielenkäytön tapojen ja vuorovaikutustehtävien avulla. Tutkimus tarjoaa tietoa nykypuhesuomen variaatiosta kolmen puhekielen piirteen kautta. Työ jättää paljon tarkasteltavaa myös tämän tutkielman jälkeiselle tutkimukselle. Edelleen selvitettäväksi jäävät monet muut kielenpiirteet ryhmän puhekielessä. Erityisen mielenkiintoinen tutkimuskohde olisi persoonapronominien variaatio (minä ~ mä ~ mää). Luonnollinen jatke tutkielmalle olisi myös ryhmän reaaliaikainen seuraaminen valittujen kielenpiirteiden osalta.

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The constitutive flow behaviour in hot working of as cast magnesium has been studied with the help of a processing map developed in the temperature range 300-550°C and strain rate range 0·001-100 s−1. The map, interpreted using the dynamic materials model, revealed that the material undergoes dynamic recrystallisation at 425°C and 0·3 s−1, which are the optimum parameters for hot working. Ai temperatures higher than 450°C and strain rates lower than about 0·1 s−1, wedge cracking occurs in as cast magnesium. The wedge cracking domain has a high efficiency of power dissipation (60%), whereas the dynamic recrystallisation domain has a value of 34%. At temperatures below 450°C and strain rates above 10 s−1, the material exhibits flow instability in the form of mechanical twinning. At higher temperatures and strain rates, instability is manifested by flow localisation.

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While the endocrine role of oestrogen is well established, its function in follicular maturation as an autocrine or paracrine regulator is less well understood. This study was designed to delineate the requirement of oestrogen for follicular development in immature rats. Exogenous gonadotrophin (25 IU pregnant mare serum gonadotrophin (PMSG) per rat) was administered to 21- to 23-day old female rats to induce follicular growth and development. In the experimental animals, synthesis of oestrogen was blocked by implanting an Alzet pump containing the aromatase inhibitor (AI) CGS 16949A (fadrozole hydrochloride; 50 mu g/rat per day). The treatment resulted in blockade of the PMSG induced increase in both serum and intrafollicular oestrogen (>95%), thus leading to an inhibition in uterine weight increment. Compared with the controls, ovarian weight increased markedly in both the PMSG (295%)- and PMSG+AI (216%)-primed animals. There was no significant difference in either the proliferative capabilities of the ovarian granulosa cells or their responsiveness to human chorionic gonadotrophin (hCG; 200 pg/ml) and ovine FSH (20 ng/ml) between the PMSG- and PMSG+AI-treated groups. Histological examination of the ovary, however, indicated a decrease in the number of healthy antral follicles in the Al-treated group compared with the PMSG-primed animals but both the groups showed a percentage increase over the controls (PMSG, 225; PMSG+AI, 158). The responsiveness of the animals to an ovulatory dose of hCG was drastically reduced (>80% inhibition of ovulation) in the oestrogen-deprived animals; this could be overriden by exogenous administration of oestrogen. In conclusion, although blocking oestrogen synthesis in the PMSG-primed rat does not seem to alter the functional properties of the isolated granulosa cells in vitro there appears to be an effect on the number of follicles which complete maturation and are able to ovulate in vivo.

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We describe a compiler for the Flat Concurrent Prolog language on a message passing multiprocessor architecture. This compiler permits symbolic and declarative programming in the syntax of Guarded Horn Rules, The implementation has been verified and tested on the 64-node PARAM parallel computer developed by C-DAC (Centre for the Development of Advanced Computing, India), Flat Concurrent Prolog (FCP) is a logic programming language designed for concurrent programming and parallel execution, It is a process oriented language, which embodies dataflow synchronization and guarded-command as its basic control mechanisms. An identical algorithm is executed on every processor in the network, We assume regular network topologies like mesh, ring, etc, Each node has a local memory, The algorithm comprises of two important parts: reduction and communication, The most difficult task is to integrate the solutions of problems that arise in the implementation in a coherent and efficient manner. We have tested the efficacy of the compiler on various benchmark problems of the ICOT project that have been reported in the recent book by Evan Tick, These problems include Quicksort, 8-queens, and Prime Number Generation, The results of the preliminary tests are favourable, We are currently examining issues like indexing and load balancing to further optimize our compiler.

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Anion-deficient perovskite oxides of the formula AM(1-x)Al(x)O(3-x) (A = Na or K; M = Nb or Ta) have been prepared for 0 < x less than or equal to 0.5. Diffraction experiments reveal that while the potassium compounds adopt orthorhombic/cubic perovskite structures similar to the parent KNbO3/KTaO3, the sodium compound, NaNb0.5Al0.5O2.5, possesses a brownmillerite/LaSr-CuAlO5-like superstructure. Al-27 NMR spectra show an exclusive tetrahedral oxygen coordination for AI(III) in Na-Nb0.5Al0.5O2.5 (I) and both tetrahedral and octahedral coordination for Al(III) in KNb0.5Al0.5O2.5 (II). The results suggest a long-range and short-range ordering of oxide ion vacancies in I and II respectively. Electrical conductivity measurements show a significant oxide ion conduction for KNb1-xAlxO3-x, with the conductivity increasing with x up to x = 0.5. The differences in the Arrhenius plots of the ionic conductivity of I and II have been rationalized in terms of the long-range and short-range ordering of oxide ion vacancies in the anion-deficient perovskite oxides.

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The present study focusses attention on the effects of blocking estrogen synthesis, during follicular phase, on follicular maturation in the adult female bonnet monkey (Macaca radiata). Administration of cycling females (n = 4) with an aromatase inhibitor CGS 16949A (AI) by Alzet mini-pump (2.5 mg/day) from day 3 of cycle resulted in significant reduction in basal (by 53%) and surge levels of estrogen (by 70%) but this had no effect on follicular maturation, ovulation and luteal function as assessed by serum hormone profiles as well as laparotomy. This lack of need for estrogen for completion of follicular maturation process was confirmed by administering cycling monkeys hFSH (25 IU/day) from day 3 till day 8 of the cycle along with (5 mg AI/day) or without Al (n = 3/group). Administration of Al resulted in suppression of FSH induced increase in serum estrogen (by 100%) and elevation in circulating androstenedione. Aromatase inhibitor treatment had no effect on either the number of follicles developed or their size relative to control. Testing the ability of both granulosa and thecal cells, removed on day 9 of treatment cycle, to respond to gonadotropins in vitro showed no change indicating that cellular development and maturation of follicular cells had occurred normally. It is concluded that follicular maturation in the primate can occur even when increase in estrogen synthesis is blocked.

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In engineering design, the end goal is the creation of an artifact, product, system, or process that fulfills some functional requirements at some desired level of performance. As such, knowledge of functionality is essential in a wide variety of tasks in engineering activities, including modeling, generation, modification, visualization, explanation, evaluation, diagnosis, and repair of these artifacts and processes. A formal representation of functionality is essential for supporting any of these activities on computers. The goal of Parts 1 and 2 of this Special Issue is to bring together the state of knowledge of representing functionality in engineering applications from both the engineering and the artificial intelligence (AI) research communities.