913 resultados para repetition tunable


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Bacterial resistance to almost all available antibiotics is an important public health issue. A major goal in antimicrobial drug discovery is the generation of new chemicals capable of killing pathogens with high selectivity, particularly multi-drug-resistant ones. Here we report the design, preparation and activity of new compounds based on a tunable, chemically accessible and upscalable lipopeptide scaffold amenable to suitable hit-to-lead development. Such compounds could become therapeutic candidates and future antibiotics available on the market. The compounds are cyclic, contain two D-amino acids for in vivo stability and their structures are reminiscent of other cyclic disulfide-containing peptides available on the market. The optimized compounds prove to be highly active against clinically relevant Gram-negative and Gram-positive bacteria. In vitro and in vivo tests show the low toxicity of the compounds. Their antimicrobial activity against resistant and multidrug-resistant bacteria is at the membrane level, although other targets may also be involved depending on the bacterial strain.

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Bacterial resistance to almost all available antibiotics is an important public health issue. A major goal in antimicrobial drug discovery is the generation of new chemicals capable of killing pathogens with high selectivity, particularly multi-drug-resistant ones. Here we report the design, preparation and activity of new compounds based on a tunable, chemically accessible and upscalable lipopeptide scaffold amenable to suitable hit-to-lead development. Such compounds could become therapeutic candidates and future antibiotics available on the market. The compounds are cyclic, contain two D-amino acids for in vivo stability and their structures are reminiscent of other cyclic disulfide-containing peptides available on the market. The optimized compounds prove to be highly active against clinically relevant Gram-negative and Gram-positive bacteria. In vitro and in vivo tests show the low toxicity of the compounds. Their antimicrobial activity against resistant and multidrug-resistant bacteria is at the membrane level, although other targets may also be involved depending on the bacterial strain.

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Bacterial resistance to almost all available antibiotics is an important public health issue. A major goal in antimicrobial drug discovery is the generation of new chemicals capable of killing pathogens with high selectivity, particularly multi-drug-resistant ones. Here we report the design, preparation and activity of new compounds based on a tunable, chemically accessible and upscalable lipopeptide scaffold amenable to suitable hit-to-lead development. Such compounds could become therapeutic candidates and future antibiotics available on the market. The compounds are cyclic, contain two D-amino acids for in vivo stability and their structures are reminiscent of other cyclic disulfide-containing peptides available on the market. The optimized compounds prove to be highly active against clinically relevant Gram-negative and Gram-positive bacteria. In vitro and in vivo tests show the low toxicity of the compounds. Their antimicrobial activity against resistant and multidrug-resistant bacteria is at the membrane level, although other targets may also be involved depending on the bacterial strain.

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Bacterial resistance to almost all available antibiotics is an important public health issue. A major goal in antimicrobial drug discovery is the generation of new chemicals capable of killing pathogens with high selectivity, particularly multi-drug-resistant ones. Here we report the design, preparation and activity of new compounds based on a tunable, chemically accessible and upscalable lipopeptide scaffold amenable to suitable hit-to-lead development. Such compounds could become therapeutic candidates and future antibiotics available on the market. The compounds are cyclic, contain two D-amino acids for in vivo stability and their structures are reminiscent of other cyclic disulfide-containing peptides available on the market. The optimized compounds prove to be highly active against clinically relevant Gram-negative and Gram-positive bacteria. In vitro and in vivo tests show the low toxicity of the compounds. Their antimicrobial activity against resistant and multidrug-resistant bacteria is at the membrane level, although other targets may also be involved depending on the bacterial strain.

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Bacterial resistance to almost all available antibiotics is an important public health issue. A major goal in antimicrobial drug discovery is the generation of new chemicals capable of killing pathogens with high selectivity, particularly multi-drug-resistant ones. Here we report the design, preparation and activity of new compounds based on a tunable, chemically accessible and upscalable lipopeptide scaffold amenable to suitable hit-to-lead development. Such compounds could become therapeutic candidates and future antibiotics available on the market. The compounds are cyclic, contain two D-amino acids for in vivo stability and their structures are reminiscent of other cyclic disulfide-containing peptides available on the market. The optimized compounds prove to be highly active against clinically relevant Gram-negative and Gram-positive bacteria. In vitro and in vivo tests show the low toxicity of the compounds. Their antimicrobial activity against resistant and multidrug-resistant bacteria is at the membrane level, although other targets may also be involved depending on the bacterial strain.

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Metal-organic frameworks (MOFs) form a new class of materials with well-defined yet tunable properties. These are crystalline, highly porous and exhibit strong metal-ligand interactions. Importantly, their physical and chemical properties, including pore size, pore structure, acidity, and magnetic and optical characteristics, can be tailored by choosing the appropriate ligands and metal precursors. Here we review the key aspects of synthesis and characterization of MOFs, focusing on lanthanide-based and vanadium-based materials. We also outline some of their applications in catalysis and materials science.

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AbstractThis work describes the development of a biosensor based on the tyrosinase enzyme (Tyr) for the determination of phenol (PHEN) in laboratory effluent samples derived from ammoniacal nitrogen analysis of the water samples from the Muquém dam in the city of Cariús, CE, using square-wave voltammetry (SWV). The electrode modification consisted of the immobilization of gold nanoparticles, multi-walled carbon nanotubes, cobalt phthalocyanine, and Tyr on a glassy carbon electrode. The electrolyte, pH, enzyme quantity, and voltammetric parameters were optimized to detect PHEN. The analytical curves presented a linear range from 4.97 × 10-6 mol L-1 to 6.10 × 10-5 mol L-1, and the detection limit (DL) and quantitation limit (QL) values were 4.81 × 10-6 mol L-1 and 4.97 × 10-6mol L-1, respectively. The repetition of measurements with the same biosensor and repetition for three other prepared biosensors exhibited a relative standard deviation (RSD) of 5.50 and 1.75%, respectively. The percentage recovery of PHEN in effluent samples varied from 86.40 to 105.04%. The stability of the biosensor was evaluated (at 21 days) with satisfactory results, showing 97.86% of the initial response. Moreover, the DL and recovery percentages agreed with the established values from CONAMA and ABNT, respectively. Thus, the electrode configuration developed seems a promising tool in the detection and quantification of PHEN in complex samples.

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Tämän kandidaatintyön tavoitteena on esittää kuvaus kulutusoppimisen teorioista ja tämän lisäksi kuvata käytännön sovelluksia liittyen kulutuskäyttäytymiseen ja mainontaan. On olemassa kaksi keskeistä ajattelutapaa liittyen oppimisen teorioihin. Ensimmäisen suuntauksen kannattajat näkevät oppimisen puhtaasti behavioristisena, eli että se on seurausta toistoista, ja siten ne näkevät yksilön "mustana laatikkona", jossa syötteenä on ärsyke ja suoritteena on tietty käytös. Toisen suuntauksen kannattajien mielestä oppiminen on kognitiivinen prosessi; kaikista yksinkertaisimmista tapauksista lähtien yksilö prosessoi informaatiota ratkaistakseen omia ongelmiaan. Käytännössä kumpaakin teoriaa tarvitaan selittämään oppimista ilmiönä, koska oppiminen on yhdistelmä toistoja ja kognitiivisia prosesseja. Työmme näyttää kuinka markkinoijat hyödyntävät näitä kahta teoriaa käytännössä mainonnassaan, tarkoituksenaan tuotemerkkinsä ja tuotteidensa asemointi markkinoilla suhteessa kilpailijoihinsa.

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The presented thesis is devoted to investigation of wave processes in hybrid ferrite / ferroelectric structures. Spin wave devices based on ferrite films have such disadvantages, as huge size of the magnetic systems, low tuning velocity, considerable power inputs for parameters control that limits possible device applications. The considered layered structures allow to overcome the disadvantages mentioned and to promote the development of novel class of tunable microwave devices. The proposed theoretical analysis is intended to construct a model of hybrid electromagnetic-spin waves. Based on the theoretical analysis the experimental investigations were carried out. The experimental resonance characteristics of ferrite / ferroelectric resonator were obtained and their tunability by means of magnetic and electric field was demonstrated.

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Tässä kvalitatiivisessa pro gradu -työssä tutkittiin kuluttajien brändikokemuksia aikakauslehtien brändeistä. Päätutkimusongelmana oli kuinka kuluttaja kokee aikakauslehden brändin. Alaongelmia olivat seuraavat: mitä ovat brändikokemukset, mitkä ovat brändikokemuksen ulottuvuudet, mitkä konseptit liittyvät brändikokemukseen, kuka on vastuussa brändikokemusten luomisesta ja miten brändikokemuksia luodaan. Tässä tutkimuksessa on analysoitu yhtä avointa kysymystä: kerro meille kokemuksiasi X lehden brändistä. Vastausten perusteella vastaajista muodostettiin kahdeksan ryhmää: Uloskasvaneet, Internet-sivujen käyttäjät, Toistoon kyllästyneet, Vertaistukijat, Nostalgiset, Uskolliset, Tyytyväiset ja Luottavaiset.

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AB STRACT This study aimed at evaluating the natural durability of Eucalyptus dunnii, Eucalyptus robusta, Eucalyptus tereticornis and Hovenia dulcis woods submitted to a deterioration test in two environments, field and forest. The test samples were buried until half of their length (150 mm). Evaluations were carried out each 45 days, totalizing a 405-day period, with three-repetition withdrawal of each species for environment, totalizing nine samples from each environment, making up 24 test samples for evaluation. After percentage calculations of mass loss and resistance degree classification, the deterioration index was adopted for decomposition evaluation and fungal decay potential determination of test samples. The study has been carried out in completely randomized design (CRD), evaluated through analysis of variance (ANOVA) with subsequent comparison of means by Turkey' s test, in a 5%-level of probability of error, along with regression analysis. Eucalyptus tereticornis wood presented lesser mass loss in both environments. Hovenia dulcis presented lesser deterioration probability in both environments. Forest environment test samples presented greater mass loss percentages and lesser deterioration index.

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The aim of this study was to evaluate the application possibility of tabular CUSUM control charts in the quality control of chemical variables in surface water. It was performed bibliographic and field research to collect water samples from 2003 to 2009, totaling 30 samples, some monthly and others semi-annual in order to observe the variables that regulate water quality. It was found that these charts may be applied to control the quality of river water; showing to be effective in the perception of changes during the process, especially for small samples (n=1) which there is no repetition as in this research. It was also concluded that the Mandurim River does not presents significant levels of pollution.

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PURPOSE: To determine fetal heart rate (FHR) responses to maternal resistance exercise for the upper and lower body at two different volumes, and after 25 minutes post-exercise.METHODS: Ten pregnant women (22-24 weeks gestation, 25.2±4.4 years of age, 69.8±9.5 kg, 161.6±5.2 cm tall) performed, at 22-24, 28-32 and 34-36 weeks, the following experimental sessions: Session 1 was a familiarization with the equipment and the determination of one estimated maximum repetition. For sessions 2, 3, 4 and 5,FHR was determined during the execution of resistance exercise on bilateral leg extension and pec-deck fly machines, with 1 and 3 sets of 15 repetitions; 50% of the weight load and an estimated repetition maximum. FHR was assessed with a portable digital cardiotocograph. Results were analyzed using Student's ttest, ANOVA with repeated measures and Bonferroni (α=0.05; SPSS 17.0).RESULTS: FHR showed no significant differences between the exercises at 22-24 weeks (bilateral leg extension=143.8±9.4 bpm, pec-deck fly=140.2±10.2 bpm, p=0.34), 28-30 weeks (bilateral leg extension=138.4±12.2 bpm, pec-deck fly=137.6±14.0 bpm, p=0.75) and 34-36 weeks (bilateral leg extension=135.7±5.8 bpm, pec-deck fly=139.7±13.3 bpm, p=0.38), between the volumes(bilateral leg extension at 22-24 weeks: p=0.36, at 28-30 weeks: p=0.19 and at 34-36 weeks: p=0.87; pec-deck fly at 22-24 weeks: p=0.43, at 28-30 weeks: p=0.61 and at 34-36 weeks: p=0.49) and after 25 minutes post-exercise.CONCLUSION: Results of this pilot study would suggest that maternal resistance exercise is safe for the fetus.

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Advanced oxidation processes (AOPs) have been studied and developed to suffice the effective removal of refractory and toxic compounds in polluted water. The quality and cost of wastewater treatment need improvements, and electric discharge technology has a potential to make a significant difference compared to other established AOPs based on energy efficiency. The generation of active oxidant species such as ozone and hydroxyl radicals by high voltage discharge is a relatively new technology for water treatment. Gas-phase pulsed corona discharge (PCD), where a treated aqueous solution is dispersed between corona-producing electrodes free of the dielectric barriers, was developed as an alternative approach to the problem. The short living radicals and ozone formed in the gas phase and at the gas-liquid interface react with dissolved impurities. PCD equipment has a relatively simple configuration, and with the reactor in an enclosed compartment, it is insensitive towards gas humidity and does not need the gas transport. In this thesis, PCD was used to study and evaluate the energy efficiency for degrading various organic compounds, as well as the chemistry of the oxidation products formed. The experiments investigate the aqueous oxidation of phenol, humic substances, pharmaceutical compounds (paracetamol, ibuprofen, indomethacin, salicylic acids, -estradiol), as well as lignin degradation and transformation to aldehydes. The study aims to establish the influence of initial concentration of the target pollutant, the pulsed discharge parameters, gas phase composition and the pH on the oxidation kinetics and the efficiency. Analytical methods to measure the concentrations of the target compounds and their by-products include HPLC, spectrophotometry, TOC and capillary electrophoresis. The results of the research included in this summary are presented in the attached publications and manuscripts accepted for publication. Pulsed corona discharge proved to be highly effective in oxidizing each of the target compounds, surpassing the closest competitor, conventional ozonation. The increase in oxidation efficiencies for some compounds in oxygen media and at lower pulse repetition frequencies shows a significant role of ozone. The role of the ·OH radicals was established in the surface reactions. The main oxidation products, formation of nitrates, and the lignin transformation were quantified. A compound specific approach is suggested for optimization of the PCD parameters that have the most significant impact on the oxidation energy efficiency because of the different characteristics and responses of the target compound to the oxidants, as well as different admixtures that are present in the wastewater. Further studies in the method’s safety (nitration and nitrosation of organic compounds, nitrite and nitrate formation enhancement) are needed for promoting the method.

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Sellunkeiton sivutuotteena syntyvä mustalipeä sisältää arvokkaita orgaanisia yhdisteitä, kuten hydroksihappoja. Toistaiseksi hydroksihapot on käytetty muun mustalipeän tavoin sellutehtaan lämmöntuotantoon. Hydroksihappojen merkitys lämmöntuotannon kannalta on kuitenkin pieni verrattuna mustalipeän sisältämään ligniiniin. Viime vuosina kiinnostus hydroksihappoja kohtaan on kasvanut sillä ne voisivat toimia lähtöaineena monille kemikaaleille, joiden valmistukseen käytetään perinteisesti fossiilisia polttoaineita. Hydroksihappoja voidaan erottaa mustalipeästä useilla eri menetelmillä. Erotukseen soveltuvia menetelmiä ovat esimerkiksi ioniekskluusiokromatografia, kalvosuodatus ja kiteytys sekä kokoekskluusiokromatografia. Kromatografisissa menetelmissä käytetyt hartsit ja kalvosuodatuksessa käytettävät kalvot ovat kuitenkin alttiita eri yhdisteiden aiheuttamalle likaantumiselle. Tämän työn kirjallisuusosassa käsitellään mustalipeän koostumusta sekä mustalipeän sisältämiä hydroksihappoja ja niiden käyttökohteita. Lisäksi kirjallisessa osassa on kuvattu aikaisemmin tutkittuja menetelmiä hydroksihappojen erottamiseksi mustalipeästä. Viimeisin menetelmä mustalipeän fraktioimiseksi on kokoekskluusiokromatografia. Työssä on kuvattu kokoeksluusiokromatografian periaate ja selvitetty menetelmän soveltuvuutta mustalipeän fraktiointiin. Lisäksi on käsitelty kromatografisissa menetelmissä käytettyjen hartsien likaantumista, likaantumisen vaikutusta erotustehokkuuteen ja likaantumisen ehkäisyä. Kokeellisessa osassa käsitellään hydroksihappojen erotusta mustalipeästä kokoekskluusiokromatografialla sekä kokoekskluusiokromatografiassa käytettävän hartsin likaantumista ja kestävyyttä. Työssä selvitettiin toistokokein likaantumisen vaikutusta hartsin erotuskykyyn käsitellyn mustalipeän määrän kasvaessa. Malliaineena käytettiin ultrasuodatettua soodakeitettyä mustalipeää. Tulosten perusteella hartsin likaantuminen ei vaikuttanut hydroksihappojen erotukseen mustalipeästä. Kestävyyskokeissa hartsin vesiretentiossa ei havaittu mittausten perusteella johdonmukaista muutosta. HPLC-analyysien perusteella huomattiin liuoksista kuitenkin mahdollisia hartsin hajoamistuotteita, joita ei kuitenkaan pystytty tunnistamaan.