958 resultados para PM-AH
Resumo:
Angiogeneesi on tärkeä ilmiö elimistön fysiologiassa, mutta myös lukuisissa patologisissa tiloissa. Angiogeneesi on monivaiheinen prosessi, joka sisältää angiogeneesiä indusoivia ja sitä inhiboivia tekijöitä tasapainossa keskenään. Useat tutkimukset puoltavat sitä, että tymosiini ȕ4 (Tȕ4) ja tetrapeptidi Ac-SDKP (N-asetyyliseryyli- aspartyyli-lysyyli-proliini) indusoivat angiogeneesiä in vitro ja in vivo. Tutkimukset viittaavat myös siihen, että prolyylioligopeptidaasi (POP) hydrolysoi peptidifragmentin Ac- SDKP Tȕ4:n (43 ah) proliinin jälkeen. POP on laajalti esiintyvä seriiniproteaasi, joka pystyy pilkkomaan vain alle 30 aminohapon oligopeptidejä. Tȕ4:n tulee siksi pilkkoutua ensin jonkin, vielä tuntemattoman peptidaasin johdosta. POP:ia on löydetty eniten aivoista, minkä vuoksi sitä on tutkittu varsinkin muistin ja oppimisen häiriötiloissa sekä neurodegeneratiivisten sairausten yhteydessä. POP:in todellinen fysiologinen merkitys on kuitenkin vielä selvittämättä. Tämän pro gradun kirjallisuusosiossa selvitetään angiogeneesiin liittyvien tekijöiden yhteyksiä sekä kuvataan angiogeenisten Tȕ4:n, Ac-SDKP:n ja POP:in ominaisuuksia, esiintymistä ja toimintaa. Kokeellisen osion tarkoituksena oli osoittaa, osallistuvatko POP ja Tȕ4 tetrapeptidin Ac-SDKP muodostumiseen ja kapillaarimuodostumiseen ja edelleen, voidaanko POPaktiivisuutta, tetrapeptidi- ja kapillaarimuodostumista estää spesifisellä POP-inhibiittorilla, KYP-2047:llä. Kokeellinen osa oli kaksiosainen. Ensimmäisessä osassa tutkittiin POPaktiivisuutta ja suoritettiin Ac-SDKP –pitoisuusmittauksia ajanjaksolla 0-180 min Wistarkannan rotista tehdyillä homogenaateilla. Tutkimusryhminä olivat 0,1 ja 0,5 μM KYP-2047 (+2 μM Tȕ4), 1:20 (0,625 μM) humaaniperäinen rekombinantti-POP (+ 2 μM Tȕ4), 2 μM Tȕ4 (pos. kontrolli) ja raakahomogenaatti (neg. kontrolli). Toisessa osassa tutkittiin kapillaarimuodostumista ajanjaksolla 0-180 min humaaniperäisillä napanuoralaskimon primaariendoteelisoluilla MatrigelTM Matrix -päällystetyllä 48- kuoppalevyllä, jolle oli siirrostettu 50 000 solua/kuoppa. Naudan seerumilla ja antibiooteilla käsitellyt tutkimusryhmät olivat 5 ja 10 μM KYP-2047 (+4 μM Tȕ4), 1:20 (0,625 μM) humaaniperäinen rekombinantti-POP (+4 μM Tȕ4), 4 μM Tȕ4 (pos. kontrolli) ja DMEM (neg. kontrolli). Kuoppia inkuboitiin ja kapillaarimuodostuminen kuvattiin valomikroskoopilla digitaalikameralla. Kutakin tutkimusryhmää pipetoitiin kolmeen rinnakkaiseen kuoppaan ja kokeet toistettiin neljästi. Sulkeutuneiden kapillaarien lukumäärä laskettiin manuaalisesti ja tuloksista tehtiin tilastollinen analyysi. 7ȕ4:n ja POP:in havaittiin molempien osallistuvan tetrapeptidin AC-SDKP muodostumiseen munuaishomogenaateissa. Primaariendoteelisolut muodostivat selkeitä kapillaareja Matrigelilla, erityisesti POP- ja Tȕ4–ryhmissä. KYP-2047 inhiboi tehokkaasti POP:ia kaikissa kokeissa osoittautuen hyväksi antiangiogeeniseksi yhdisteeksi. Angiogeneesin mekanismien ja POP:in, Tȕ4:n ja Ac-SDKP:n yhteyksien selvittäminen vaatii luonnollisesti vielä lisätutkimuksia.
Resumo:
We performed a signature-based search for long-lived charged massive particles (CHAMPs) produced in 1.0 $\rm{fb}^{-1}$ of $\bar{p}p$ collisions at $\sqrt{s}=1.96$ TeV, collected with the CDF II detector using a high transverse-momentum ($p_T$) muon trigger. The search used time-of-flight to isolate slowly moving, high-$p_T$ particles. One event passed our selection cuts with an expected background of $1.9 \pm 0.2$ events. We set an upper bound on the production cross section, and, interpreting this result within the context of a stable scalar top quark model, set a lower limit on the particle mass of 249 GeV/$c^2$ at 95% C.L.
Resumo:
We present a measurement of the top quark mass with t-tbar dilepton events produced in p-pbar collisions at the Fermilab Tevatron $\sqrt{s}$=1.96 TeV and collected by the CDF II detector. A sample of 328 events with a charged electron or muon and an isolated track, corresponding to an integrated luminosity of 2.9 fb$^{-1}$, are selected as t-tbar candidates. To account for the unconstrained event kinematics, we scan over the phase space of the azimuthal angles ($\phi_{\nu_1},\phi_{\nu_2}$) of neutrinos and reconstruct the top quark mass for each $\phi_{\nu_1},\phi_{\nu_2}$ pair by minimizing a $\chi^2$ function in the t-tbar dilepton hypothesis. We assign $\chi^2$-dependent weights to the solutions in order to build a preferred mass for each event. Preferred mass distributions (templates) are built from simulated t-tbar and background events, and parameterized in order to provide continuous probability density functions. A likelihood fit to the mass distribution in data as a weighted sum of signal and background probability density functions gives a top quark mass of $165.5^{+{3.4}}_{-{3.3}}$(stat.)$\pm 3.1$(syst.) GeV/$c^2$.
Resumo:
We present a measurement of the tt̅ production cross section in pp̅ collisions at √s=1.96 TeV using events containing a high transverse momentum electron or muon, three or more jets, and missing transverse energy. Events consistent with tt̅ decay are found by identifying jets containing candidate heavy-flavor semileptonic decays to muons. The measurement uses a CDF run II data sample corresponding to 2 fb-1 of integrated luminosity. Based on 248 candidate events with three or more jets and an expected background of 79.5±5.3 events, we measure a production cross section of 9.1±1.6 pb.
Resumo:
We present a measurement of the top quark mass in the all-hadronic channel (\tt $\to$ \bb$q_{1}\bar{q_{2}}q_{3}\bar{q_{4}}$) using 943 pb$^{-1}$ of \ppbar collisions at $\sqrt {s} = 1.96$ TeV collected at the CDF II detector at Fermilab (CDF). We apply the standard model production and decay matrix-element (ME) to $\ttbar$ candidate events. We calculate per-event probability densities according to the ME calculation and construct template models of signal and background. The scale of the jet energy is calibrated using additional templates formed with the invariant mass of pairs of jets. These templates form an overall likelihood function that depends on the top quark mass and on the jet energy scale (JES). We estimate both by maximizing this function. Given 72 observed events, we measure a top quark mass of 171.1 $\pm$ 3.7 (stat.+JES) $\pm$ 2.1 (syst.) GeV/$c^{2}$. The combined uncertainty on the top quark mass is 4.3 GeV/$c^{2}$.
Resumo:
We present a measurement of the tt̅ production cross section in pp̅ collisions at √s=1.96 TeV using events containing a high transverse momentum electron or muon, three or more jets, and missing transverse energy. Events consistent with tt̅ decay are found by identifying jets containing candidate heavy-flavor semileptonic decays to muons. The measurement uses a CDF run II data sample corresponding to 2 fb-1 of integrated luminosity. Based on 248 candidate events with three or more jets and an expected background of 79.5±5.3 events, we measure a production cross section of 9.1±1.6 pb.
Resumo:
Superplastic materials exhibit very large elongations to failure,typically >500%, and this enables commercial forming of complex shaped components at slow strain rates of similar to 10(-4) s(-1). We report extraordinary record superplastic elongations to failure of up to 5300% at both high strain rates and low temperature in electrodeposited nanocrystalline Ni and some Ni alloys. Superplasticity is not related to the presence of sulfur or a low melting phase at grain boundaries. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Resumo:
The line spectral frequency (LSF) of a causal finite length sequence is a frequency at which the spectrum of the sequence annihilates or the magnitude spectrum has a spectral null. A causal finite-length sequencewith (L + 1) samples having exactly L-LSFs, is referred as an Annihilating (AH) sequence. Using some spectral properties of finite-length sequences, and some model parameters, we develop spectral decomposition structures, which are used to translate any finite-length sequence to an equivalent set of AH-sequences defined by LSFs and some complex constants. This alternate representation format of any finite-length sequence is referred as its LSF-Model. For a finite-length sequence, one can obtain multiple LSF-Models by varying the model parameters. The LSF-Model, in time domain can be used to synthesize any arbitrary causal finite-length sequence in terms of its characteristic AH-sequences. In the frequency domain, the LSF-Model can be used to obtain the spectral samples of the sequence as a linear combination of spectra of its characteristic AH-sequences. We also summarize the utility of the LSF-Model in practical discrete signal processing systems.
Resumo:
We present a measurement of the $\ttbar$ production cross section in $\ppbar$ collisions at $\sqrt{s}=1.96$ TeV using events containing a high transverse momentum electron or muon, three or more jets, and missing transverse energy. Events consistent with $\ttbar$ decay are found by identifying jets containing candidate heavy-flavor semileptonic decays to muons. The measurement uses a CDF Run II data sample corresponding to $2 \mathrm{fb^{-1}}$ of integrated luminosity. Based on 248 candidate events with three or more jets and an expected background of $79.5\pm5.3$ events, we measure a production cross section of $9.1\pm 1.6 \mathrm{pb}$.
Resumo:
We report a measurement of the top quark mass $M_t$ in the dilepton decay channel $t\bar{t}\to b\ell'^{+}\nu'_\ell\bar{b}\ell^{-}\bar{\nu}_{\ell}$. Events are selected with a neural network which has been directly optimized for statistical precision in top quark mass using neuroevolution, a technique modeled on biological evolution. The top quark mass is extracted from per-event probability densities that are formed by the convolution of leading order matrix elements and detector resolution functions. The joint probability is the product of the probability densities from 344 candidate events in 2.0 fb$^{-1}$ of $p\bar{p}$ collisions collected with the CDF II detector, yielding a measurement of $M_t= 171.2\pm 2.7(\textrm{stat.})\pm 2.9(\textrm{syst.})\mathrm{GeV}/c^2$.
Resumo:
Hormone therapy (HT) is widely used to relieve climacteric symptoms in order to increase the well-being of the women. The benefits as well as side-effects of HT are well documented. The principal menopausal oral symptoms are dry mouth (DM) and sensation of painful mouth (PM) due to various causes. Profile studies have indicated that HT users are more health-conscious than non-users. The hypothesis of the present study was that there are differences in oral health between woman using HT and those not using HT. A questionnaire study of 3173 women of menopausal age (50-58 years old) was done to investigate the prevalence of self-assessed sensations of PM and DM. Of those women participating in the questionnaire study, a random sample of 400 (200 using, 200 not using HT) was examined clinically in a 2-year follow-up study. Oral status was recorded according to WHO methods using DMFT and CPITN indices. The saliva flows were measured, salivary total protein, albumin and immunoglobulin concentrations and selected periodontal micro-organisms were analysed, and panoramic tomography of the jaws was taken. The patients filled in a structured questionnaire on their systemic health, medication and health habits. According to our questionnaire study there was no significant difference in the occurrence of self- assessed PM or DM between the HT users and non-users. According to logistic regression analyses, climacteric complaints significantly correlated with the occurrence of PM (p=0.000) and DM (p=0.000) irrespective of the use of HT, indicating that PM and DM are associated with climacteric symptoms in general. There was no difference between the groups in DMFT index values at follow up. The number of filled teeth (FT) showed a significant (p<0.05) increase in the HT group at follow-up. Periodontitis was diagnosed in 79% of HT users at baseline and in 71% at the follow-up. The values for non-HT users were 80% vs. 76%, respectively (Ns.). The mean numbers of ≥ 6 mm deep periodontal pockets were 0.9 ± 1.7 at baseline vs. 1.1 ± 2.1 two years later in the HT group, and 1.0 ± 1.7 vs. 1.2 ± 1.9, respectively, in the non-HT group. In a large Finnish national health survey, the prevalence of peridontitis of women of this age group was lower, but the prevalence of severe periodontitis seemed to be higher than in our study. Salivary albumin, IgG and IgM concentrations decreased in the HT group during the 2-year follow up (p<0.05), possibly indicating an improvement in epithelial integrity. No difference was found in any other salivary parameters or in the prevalence of the periodontal bacteria between or within the groups. In conclusion, the present findings showed that 50 to 58 year old women living in Helsinki have fairly good oral and dental health. The occurrence of PM and DM seemed to be associated with climacteric symptoms in general, and the use of HT did not affect the oral symptoms studied.
Resumo:
The purpose of this study is to experimentally investigate the interaction of inelastic deformation and microstructural changes of two Zr-based bulk metallic glasses (BMGs): Zr41.25Ti13.75Cu12.5Ni10Be22.5 (commercially designated as Vitreloy 1 or Vit1) and Zr46.75Ti8.25Cu7.5Ni10Be27.5 (Vitreloy 4, Vit4). High-temperature uniaxial compression tests were performed on the two Zr alloys at various strain rates, followed by structural characterization using differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). Two distinct modes of mechanically induced atomic disordering in the two alloys were observed, with Vit1 featuring clear phase separation and crystallization after deformation as observed with TEM, while Vit4 showing only structural relaxation with no crystallization. The influence of the structural changes on the mechanical behaviors of the two materials was further investigated by jump-in-strain-rate tests, and flow softening was observed in Vit4. A free volume theory was applied to explain the deformation behaviors, and the activation volumes were calculated for both alloys.
Resumo:
A polymer containing electron-rich aromatic donors (1,5-dialkoxynaphthalene (DAN)) was coerced into a folded state by an external folding agent that contained an electron-deficient aromatic acceptor (pyromellitic diimide (PM)) unit. The donor-containing polymer was designed to carry a tertiary amine moiety in the linking segment, which served as an H-bonding site for reinforcing the interaction with the acceptor containing folding agent that also bore a carboxylic acid group. The H-bonding interaction of the carboxylic acid and the tertiary amine brings the PDI unit between two adjacent DAN units along the polymer backbone to induce charge-transfer (C-T) interactions, and this in turn causes the polymer chain to form a pleated structure. Evidence for the formation of such a pleated structure was obtained from NMR titration studies and also by monitoring the C-T band in their UV-visible spectra. By varying the length of the segment that links the PDI acceptor to the carboxylic acid group, we showed that the most effective folding agent was the one that had a single carbon spacer, as evident from the highest value of the association constant. Control experiments with propionic acid clearly demonstrated the importance of the additional C-T interactions for venerating the folded structures. Further, solution viscosity measurements in the presence of varying amounts of the folding agent revealed a gradual stiffening of the chain in the case of the PDI carrying carboxylic acid, whereas no such affect was seen in the case of simple propionic acid. These observations were supported by D FT calculations of the interactions of a dimeric model of the polymer with the various folding agents; here too the stability of the complex was seen to be highest in the case of the single carbon spacer.
Resumo:
We provide a comparative performance analysis of network architectures for beacon enabled Zigbee sensor clusters using the CSMA/CA MAC defined in the IEEE 802.15.4 standard, and organised as (i) a star topology, and (ii) a two-hop topology. We provide analytical models for obtaining performance measures such as mean network delay, and mean node lifetime. We find that the star topology is substantially superior both in delay performance and lifetime performance than the two-hop topology.
Resumo:
During the course of genome studies in a rural community in the South Indian state of Karnataka, DNA-based investigations and counselling for familial adenomatous polyposis (FAP) were requested via the community physician. The proposita died in 1940 and FAP had been clinically diagnosed in 2 of her 5 children, both deceased. DNA samples from 2 affected individuals in the third generation were screened for mutations in the APC gene, and a frame-shift mutation was identified in exon 15 with a common deletion at codon 1061. Predictive testing for the mutation was then organized on a voluntary basis. There were 11 positive tests, including confirmatory positives on 2 persons diagnosed by colonoscopy, and to date surgery has been successfully undertaken on 3 previously undiagnosed adults. The ongoing success of the study indicates that, with appropriate access to the facilities offered by collaborating centres, predictive testing is feasible for diseases such as FAP and could be of significant benefit to communities in economically less developed countries.