990 resultados para 338.064
Resumo:
Metal nanoparticle photocatalysts have attracted recent interest due to their strong absorption of visible and ultraviolet light. The energy absorbed by the metal conduction electrons and the intense electric fields in close proximity, created by the localized surface plasmon resonance effect, makes the crucial contribution of activating the molecules on the metal nanoparticles which facilitates chemical transformation. There are now many examples of successful reactions catalyzed by supported nanoparticles of pure metals and of metal alloys driven by light at ambient or moderate temperatures. These examples demonstrate these materials are a novel group of efficient photocatalysts for converting solar energy to chemical energy and that the mechanisms are distinct from those of semiconductor photocatalysts. We present here an overview of recent research on direct photocatalysis of supported metal nanoparticles for organic synthesis under light irradiation and discuss the significant reaction mechanisms that occur through light irradiation.
Resumo:
The solubilities of two fatty acids, namely hexadecanoic acid (palmitic acid) and octadecanoic acid (stearic acid) in supercritical carbon dioxide (SCCO2), were determined at T = (328 and 338) K from 12.8 MPa to 22.6 MPa. Three models, namely a thermodynamic model based on the Peng-Robinson equation of state with Kwak and Mansoori mixing rules, a model based on dilute solution theory proposed by Mendez-Santiago and Teja and a new reformulated Chrastil equation model, were used to correlate the solubilities. In all the models, the correlation constants are temperature independent. All the models successfully correlated the experimental results for the solubilities of hexadecanoic acid within 3%.
Resumo:
Aromatic aldehydes and aryl isocyanates do not react at room temperature. However, we have shown for the first time that in the presence of catalytic amounts of group(IV) n-butoxide, they undergo metathesis at room temperature to produce imines with the extrusion of carbon dioxide. The mechanism of action has been investigated by a study of stoichiometric reactions. The insertion of aryl isocyanates into the metal n-butoxide occurs very rapidly. Reaction of the insertion product with the aldehyde is responsible for the metathesis. Among the n-butoxides of group(IV) metals, Ti((OBu)-Bu-n)(4) (8aTi) was found to be more efficient than Zr((OBu)-Bu-n)(4) (8aZr) and Hf((OBu)-Bu-n)(4) (8aHf) in carrying out metathesis. The surprisingly large difference in the metathetic activity of these alkoxides has been probed computationally using model complexes Ti(OMe)(4) (8bTi), Zr(OMe)(4) (8bZr) and Hf(OMe)(4) (8bHf) at the B3LYP/LANL2DZ level of theory. These studies indicate that the insertion product formed by Zr and Hf are extremely stable compared to that formed by Ti. This makes subsequent reaction of Zr and Hf complexes unfavorable.
Resumo:
Background We aimed to assess the effect of afatinib on overall survival of patients with EGFR mutation-positive lung adenocarcinoma through an analysis of data from two open-label, randomised, phase 3 trials. Methods Previously untreated patients with EGFR mutation-positive stage IIIB or IV lung adenocarcinoma were enrolled in LUX-Lung 3 (n=345) and LUX-Lung 6 (n=364). These patients were randomly assigned in a 2:1 ratio to receive afatinib or chemotherapy (pemetrexed-cisplatin [LUX-Lung 3] or gemcitabine-cisplatin [LUX-Lung 6]), stratified by EGFR mutation (exon 19 deletion [del19], Leu858Arg, or other) and ethnic origin (LUX-Lung 3 only). We planned analyses of mature overall survival data in the intention-to-treat population after 209 (LUX-Lung 3) and 237 (LUX-Lung 6) deaths. These ongoing studies are registered with ClinicalTrials.gov, numbers NCT00949650 and NCT01121393. Findings Median follow-up in LUX-Lung 3 was 41 months (IQR 35–44); 213 (62%) of 345 patients had died. Median follow-up in LUX-Lung 6 was 33 months (IQR 31–37); 246 (68%) of 364 patients had died. In LUX-Lung 3, median overall survival was 28·2 months (95% CI 24·6–33·6) in the afatinib group and 28·2 months (20·7–33·2) in the pemetrexed-cisplatin group (HR 0·88, 95% CI 0·66–1·17, p=0·39). In LUX-Lung 6, median overall survival was 23·1 months (95% CI 20·4–27·3) in the afatinib group and 23·5 months (18·0–25·6) in the gemcitabine-cisplatin group (HR 0·93, 95% CI 0·72–1·22, p=0·61). However, in preplanned analyses, overall survival was significantly longer for patients with del19-positive tumours in the afatinib group than in the chemotherapy group in both trials: in LUX-Lung 3, median overall survival was 33·3 months (95% CI 26·8–41·5) in the afatinib group versus 21·1 months (16·3–30·7) in the chemotherapy group (HR 0·54, 95% CI 0·36–0·79, p=0·0015); in LUX-Lung 6, it was 31·4 months (95% CI 24·2–35·3) versus 18·4 months (14·6–25·6), respectively (HR 0·64, 95% CI 0·44–0·94, p=0·023). By contrast, there were no significant differences by treatment group for patients with EGFR Leu858Arg-positive tumours in either trial: in LUX-Lung 3, median overall survival was 27·6 months (19·8–41·7) in the afatinib group versus 40·3 months (24·3–not estimable) in the chemotherapy group (HR 1·30, 95% CI 0·80–2·11, p=0·29); in LUX-Lung 6, it was 19·6 months (95% CI 17·0–22·1) versus 24·3 months (19·0–27·0), respectively (HR 1·22, 95% CI 0·81–1·83, p=0·34). In both trials, the most common afatinib-related grade 3–4 adverse events were rash or acne (37 [16%] of 229 patients in LUX-Lung 3 and 35 [15%] of 239 patients in LUX-Lung 6), diarrhoea (33 [14%] and 13 [5%]), paronychia (26 [11%] in LUX-Lung 3 only), and stomatitis or mucositis (13 [5%] in LUX-Lung 6 only). In LUX-Lung 3, neutropenia (20 [18%] of 111 patients), fatigue (14 [13%]) and leucopenia (nine [8%]) were the most common chemotherapy-related grade 3–4 adverse events, while in LUX-Lung 6, the most common chemotherapy-related grade 3–4 adverse events were neutropenia (30 [27%] of 113 patients), vomiting (22 [19%]), and leucopenia (17 [15%]). Interpretation Although afatinib did not improve overall survival in the whole population of either trial, overall survival was improved with the drug for patients with del19 EGFR mutations. The absence of an effect in patients with Leu858Arg EGFR mutations suggests that EGFR del19-positive disease might be distinct from Leu858Arg-positive disease and that these subgroups should be analysed separately in future trials.
Resumo:
Advertising and marketing institutions produce categorisations of different groups of population. These categorisations serve as tools for addressing the potential consumers. This research is about how and what kind of categorisations of consumerhood are produced and how they are used as governing patterns within the institutions of advertising. My goal is to shed light on methods, cultural patterns and discourses for making people become consumers, objects for marketing measures. The data consists of 23 qualitative thematic interviews with Finnish advertising professionals. Moreover, examples are drawn from professional magazines and brochures of media agencies and marketing research organisations. First, I present some of the the official consumer categories in the consumer monitors produced by research organisations. Then, I analyse the unofficial consumer categories which are produced by advertising professionals in the interviews. The methodological framework is based on discourse theory and especially on Michel Foucault s ideas on power, governmentality, and discourses. Discursive categorisation of the population is one of the means of governmentality used in marketing and advertising. Knowledge of the consumer research is used as a tool for governing the potential consumers. Even though the real consumers always have a possibility to behave against the marketer s wishes. The marketers can not make people buy certain products or services, but they aim at influencing people in a way that they want to buy the products and start to govern themselves. As result, I present six unofficial discursive consumer categories, which are used by the advertising professionals. The consumerhood may be represented as rational, self-fulfilling, indifferent, whimsical, manipulated or sovereign. However, The discursive consumer categorisations are overlapping and controversial. The interviewed advertising professionals construct their own particular position in relation to the consumers which are viewed as others . On the other, the interviewees may talk about themselves as consumers. Finally, I maintain that the consumers and target groups of advertising are viewed as commodities in advertising institutions. The end product of the product development is not only the product but the aim is to produce the consumer of the product. The research of the ways advertising professionals aim to govern the consumers gives knowledge on the networks of power in which people act within consumer culture.
Resumo:
We report the most restrictive direct limits on masses of fourth-generation down-type quarks b′, and quarklike composite fermions (B or T5/3), decaying promptly to tW∓. We search for a significant excess of events with two same-charge leptons (e, μ), several hadronic jets, and missing transverse energy. An analysis of data from pp̅ collisions with an integrated luminosity of 2.7 fb-1 collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits mb′, mB>338 GeV/c2 and mT5/3>365 GeV/c2 at 95% confidence level.
Resumo:
We report the most restrictive direct limits on masses of fourth-generation down-type quarks $b^{\prime}$, and quark-like composite fermions ($B$ or $T_{5/3}$), decaying promptly to $t W^{\mp}$. We search for a significant excess of events with two same-charge leptons ($e$, $\mu$), several hadronic jets, and missing transverse energy. An analysis of data from $p\overline{p}$ collisions with an integrated luminosity of 2.7 fb$^{-1}$ collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits $m_{b^{\prime}}, m_{B} >$ 338 $\mathrm{GeV}/c^2$ and $m_{T_{5/3}} >$ 365 $\mathrm{GeV}/c^2$ at 95% confidence level.
Resumo:
The Raman spectrum of cyclohexanol has been studied in detail in the liquid state at 30° C. and at about 68° C. and in the solid state at about 13° C. The O-H stretching frequency of cyclohexanol has been found to extend from 3106-3571 cm.-1 in the liquid state at 30° C. and from 3204-3652 cm.-1 at 68° C. The 38 lines recorded in the present investigation have been following frequency shifts: 342, 408, 458, 478, 555, 653, 789, 834, 843, 863, 887, 920, 966, 978, 1024, 1047, 1070, 1139, 1173, 1184, 1210, 1235, 1252, 1301, 1329, 1346, 1362, 1438, 1448, 1464, 2660, 2684, 2710, 2854, 2896, 2925, 2940, 3106 to 3511 (band). Those lines which are italicized are the additional lines observed for the first time. The Raman lines at 966 cm.-1 and 1070 cm.-1 have been assigned to C-OH stretching vibrations of the axial and equatorial isomers. The ratio of the integrated intensity of the 1070 cm.-1 line to the 966 cm.-1 gave the equilibrium constant K as 2·896 at 30° C. and as 2·66 at 68° C. Knowing K, the free energy different Δ F was calculated and it was found to be 0·64 Kcal./mole at 30° C. and 0·66 Kcal./mole at about 68° C. Reasonable assignment has been made for most of the observed Raman lines.
Resumo:
Tiivistelmä Maaraportin tavoitteena on luoda yleiskatsaus Italian kolmanteen sektoriin ja tutkimus kohdistuu erityisesti Pohjois-Italiassa sijaitsevan Veneton läänin kolmannen sektorin palvelutuotantoon. Raportissa tarkastellaan erityisesti kolmannen sektorin ja julkisen palvelutuotantosektorin sekä julkishallinnon toiminnallisia suhteita. Kolmannen sektorin mahdollisuuksia vastata maaseutualueiden palvelujen tarjonnan haasteisiin on pyritty analysoimaan. Italia on julkishallinnon ja kolmannen sektorin palvelutuotannon kannalta tarkasteltuna nykytilanteessa mielenkiintoinen testilaboratorio koko Euroopan mittakaavassa johtuen maan historiallisista, kulttuuri-sista, kieli- ja maantieteellisistä sekä itse väestöpohjan tarjoamista haasteista. Italiasta ei voida puhua yhden homogeenisen valtiokäsitteen alla, koska maa toimii kulttuurisista perinteistään johtuen kolmella eri nopeudella. Itse valtio käsitettäkin tulkitaan Italiassa monin eri tavoin pohjautuen ”valtiona” nähdyn organisaation käytännön funktioon sitoutuneena alueellisiin ja kulttuurisiin tekijöihin. Teollinen, dynaaminen yritysten varakas Pohjois-Italia henkilöityneenä Milanoon, hallinnon ja kulttuurin leimaama Keski-Italia kiteytyneenä ikuiseen kaupunkiin Roomaan ja Napolin alapuolinen Etelä-Italia, joka painii ”järjestelmässä sisällä olevan järjestelmänsä” kanssa eivät ole koskaan muodos-taneet oikeasti yhtenäistä Italian valtiota. Italiassa erillisinä itsehallinnollisina alueina toimivat lääneiksi luettavat Sisilia, Trentino Alto-Adige, Val di Aosta, Sardegna ja Friuli-Venezia Giulia, mikä lisää hallinnollista kirjavuutta. Viimeisten vuosien aikana Italian julkishallinto on ollut jatkuvassa transitiotilassa yrittäessään kohdata uudistumisen vaateita globalisoituvassa maailmassa. Italiassa on meneillään hidas siirtyminen liittovaltiomaiseen järjestelmään ja jopa syvempään paikallisuuteen. Massiivinen ja raskas julkishallintokoneisto neljällä eri tasolla (valtio - lääninhallinnolliset alueet - vahvat maakunnat - kunnat) on erittäin hankalasti modernisoitavissa, mutta poliittinen tahtotila on vaihtumassa klassista vahvaa keskushallintoa kannattavasta ajattelutavasta hyväksymään federalistisia, alueellisia hallintoratkaisuja. Italiassa on herätty havaitsemaan, että ongelmien ratkaisu täytyy viedä itse alueille ja niiden ihmisille, koska unilateraalinen keskushallinnointitapa ei enää vastaa monikerroksisiin, moniulotteisiin alueellisiin haasteisiin. Jokaisella alueella on erilaiset lähtökohdat ongelmien ratkaisuihin myös globalisoitumisen asettamissa yhteisissä haasteissa. Kolmannen sektorin asema arvostettuna italialaisten kansalaispalvelujen täydentäjänä ja tuottajana alkaa olla nykypäivää. Kolmannen sektorin elintärkeä osuus uusien palvelutarpeiden tunnistamisessa on jo yleisesti tunnustettu tosiasia Italiassa. Vapaaehtoisjärjestöt toimivat eturivissä kansalaisten arkipäivässä ja pystyvät näin kanavoimaan ensimmäisinä sosiaalista kehityskulkua ja kohottamaan esiin erilaisia marginaalistenkin ryhmien tarpeita sekä vastaamaan niihin. Kolmas sektori laajentaa, tuottaa ja paikkaa paikallista julkista palvelutuotantoa. Ratkaiseva askel lainsäädännölliseltä kannalta on ollut rahoitusvirtojen ohjaaminen kolmannen sektorin ns. ONLUS-organisaatioille ja ONLUS-statuksen perustaminen vuonna 1997. Italiassa on 60 231.214 asukasta (31.7.2009) ja se on hallinnollisesti jakaantuneena 8 100 kuntaan. Suomessa vastaavat luvut ovat 5 350 712 asukasta ja 348 kuntaa (11/2009). Maantieteelliseltä kooltaan Italia ei eroa 301 338 km2:n pinta-alallaan paljonkaan Suomesta (338 424 km2). Väestömäärän erojen vuoksi Italiassa on keskimäärin 199,9 asukasta neliökilometrillä ja Suomessa 17,1. Maiden välinen suora vertailu ei ollut mittakaavaerojen vuoksi järkevää. Kuntien hallinnollinen rooli on Italiassa painotukseltaan erilainen kuin Suomessa. Suomessa kuntien vastuulla oleva sosiaali-, terveydenhuolto- ja koulutoimi eivät ole samassa laajuudessa italialaisten kuntien vastuulla vaan näiden toimialojen vastuulliset tahot ovat läänit terveydenhoitopiireineen sekä maakuntahallinto koulupiirien osalta. Italialaisten kuntien vastuualueet voivat myös vaihdella mittavasti perustuslaissa määriteltyjen perustoimien lisäksi. Tutkimuksen kohteeksi on rajattu Koillis-Italiassa sijaitseva Veneton läänin alue, koska se on väkimäärältään lähes yhtä suuri kuin Suomi, 4 893 309 asukasta (31.3.2009). Kuntien lukumäärä on huimaava 581 kpl. Veneto on maantieteelliseltä alueeltaan pieni ja harvaan asuttua maaseutua on pinta-alasta melko niukasti. Pohjoisen osan vuoristoalueet karuine olosuhteineen muodostavat palvelutuotannollisesti haas-teellisen ympäristön, joka on verrattavissa suomalaisten maaseutualueiden tilanteeseen. Venetossa on omaksuttu Italian mittakaavassa innovatiivisia ratkaisuja julkishallinnon palvelutuotannon ja kolmannen sektorin toiminnan osalta. Veneton alue on luokiteltu maailman pienyritysintensiivisimmäksi alueeksi, mikä heijastuu myös alueen palvelutuotantoratkaisuissa. Raportti esittelee ensin Italian hallintoa, keskushallinnon, paikallishallinnon ja tutkimuksen asettelulle olennaisten kolmannen sektorin toimijoiden osalta. Tämä on välttämätöntä, sillä kolmannen sektorin toiminta on Italiassa hyvin pitkälle lainsäädännöllä ohjattua ja rajattua. Kolmannen sektorin käsitteistöä, toimijoita, järjestäytymistä ja sen toimintaa säätelevää lainsäädäntöä esitellään tarkemmin. Veneton läänin osalta kolmanteen sektoriin perehdytään sekä hallinnon että toimijakentän näkökulmia tulkiten. Raportin lopussa esitellään kolmannen sektorin palvelutuotantoon ja hallinnointiin liittyviä case-esimerkkitapauksia.
Resumo:
Denoising of images in compressed wavelet domain has potential application in transmission technology such as mobile communication. In this paper, we present a new image denoising scheme based on restoration of bit-planes of wavelet coefficients in compressed domain. It exploits the fundamental property of wavelet transform - its ability to analyze the image at different resolution levels and the edge information associated with each band. The proposed scheme relies on the fact that noise commonly manifests itself as a fine-grained structure in image and wavelet transform allows the restoration strategy to adapt itself according to directional features of edges. The proposed approach shows promising results when compared with conventional unrestored scheme, in context of error reduction and has capability to adapt to situations where noise level in the image varies. The applicability of the proposed approach has implications in restoration of images due to noisy channels. This scheme, in addition, to being very flexible, tries to retain all the features, including edges of the image. The proposed scheme is computationally efficient.
Resumo:
Rare earth exchanged H–Y zeolites were prepared by simple ion exchange methods at 353 K and have been characterized using different physicochemical techniques. A strong peak around 58 ppm in the 27Al{1H} MAS NMR spectra of these zeolites suggests a tetrahedral coordination for the framework aluminium. Small peak at or near 0 ppm is due to hexa-coordinated extra-framework aluminium and a shoulder peak near 30 ppm is a penta-coordinated aluminium species; [Al(OH)4]−. The vapor-phase benzene alkylation with 1-decene and 1-dodecene was investigated with these catalytic systems. Under the reaction conditions of 448 K, benzene/olefin molar ratio of 20 and time on stream 3 h, the most efficient catalyst was CeH–Y which showed more than 70% of olefin conversion with 48.5% 2-phenyldecane and 46.8%, 2-phenyldodecane selectivities with 1-decene and 1-dodecene respectively.
Resumo:
Kinetic measurements of enzyme activity indicate that type I pantothenate kinase from Mycobacterium tuberculosis has dual substrate specificity for ATP and GTP, unlike the enzyme from Escherichia coli, which shows a higher specificity for ATP. A molecular explanation for the difference in the specificities of the two homologous enzymes is provided by the crystal structures of the complexes of the M. tuberculosis enzyme with (1) GMPPCP and pantothenate, (2) GDP and phosphopantothenate, (3) GDP, (4) GDP and pantothenate, (5) AMPPCP, and (6) GMPPCP, reported here, and the structures of the complexes of the two enzymes involving coenzyme A and different adenyl nucleotides reported earlier. The explanation is substantially based on two critical substitutions in the amino acid sequence and the local conformational change resulting from them. The structures also provide a rationale for the movement of ligands during the action of the mycobacterial enzyme. Dual specificity of the type exhibited by this enzyme is rare. The change in locations of ligands during action,observed in the case of the M. tuberculosis enzyme, is unusual, so is the striking difference between two homologous enzymes in the geometryof the binding site, locations of ligands, and specificity. Furthermore, the dual specificity of the mycobacterial enzyme appears to have been caused by a biological necessity. (C) 2010 Elsevier Ltd.All rights reserved.
Resumo:
The conformational analysis of a pair of two-linked peptide units in the anti-parallel arrangement is reported here with a view to study the effect of association of one chain with the other. The pair of two-linked peptide units were fixed in space through the hydrogen bonds between them, in accordance with certain hydrogen bond criteria. Model building was undertaken to ascertain whether the proximity of the side-chains could be used to eliminate any one of the right-hand twisted, left-hand twisted or regular β-structures. Stereochemically, it was found possible with all of them. The preference for a right-hand twisted β-structure, however, was indicated by the classical energy calculations. The relevance of the results thus obtained is discussed in the context of the preferential right-hand twist of the β-pleated sheets present in globular proteins. The agreement between the minimum energy conformations obtained for the pair of two-linked peptide units and the globular protein data is also indicated.
Resumo:
The properties of thin films depend to a large extent upon their mechanical stability which in turn is dependent on the intrinsic stresses developed during evaporation. This paper describes a simple method for the measurement of stresses in thin films by the use of real-time holographic interferometry.