Partículas nanométricas de ferritas de ítrio

Nanoparticles of yttrium iron garnet (YIG) were obtained by coprecipitation. The particles were prepared by hydrolysis in acid medium with addition of ammonia or urea, for homogeneous nucleation, at 90ºC. Different compositions and spherical morphologies were achieved by changing reactants concentrations and precipitation agent. X-ray diffractometry, transmission electron microscopy, differential thermal analysis and electrophoretic mobility were carried out on these particles to investigate the obtained phase, phase transition temperature, morphology, particle size and zeta potential, respectively.

Propulsor pneumático versátil e isento de pulsação para sistemas de análise em fluxo

Aquarium air pumps are proposed and evaluated as pneumatic liquid propulsion devices for flow injection and continuos flow analysis (FIA and CFA) systems. This kind of pump is widely available at a very low cost and it can sustain a pressure around of 4 psi (0.28 bar) indefinitely. By applying this air pressure onto a solution contained in a reservoir flask, it is possible to reach flow rates of up to 12.5 mL min-1 for circuits comprising reactors, made from 0.8 i.d. tubing with a length of 100 cm. The precise adjustment of flow rate below the maximum one can be made with a simplified needle valve or inserting in series a short length of capillary tube. The absence of flow pulsation is a definite advantage in comparison with peristaltic pumps, especially when amperometric detection is elected, as confirmed experimentally in FIA and CF applications.

Biohajoavat kompleksinmuodostajat mekaanisen massan peroksidivalkaisussa

Mekaanisen massan peroksidivalkaisussa on perinteisesti käytetty kahta kompleksinmuodostajaa, jotka ovat dietyleenitriamiinipentaetikkahappo (DTPA) ja etyleenidiamiinipentaetikkahappo (EDTA). Kompleksinmuodostajat saavat aikaan hyvän kelatointituloksen muodostamalla valkaisulle haitallisten metalli-ionien kanssa kompleksin ja estäen näin metalli-ionien valkaisutulosta huonontavan vaikutuksen. Perinteiset kompleksinmuodostajat DTPA ja EDTA eivät kuitenkaan ole biohajoavia ja niiden epäillään irrottavan metalleja vesistöjen sedimenteistä. Työssä selvitettiin kolmen eri biohajoavan kompleksinmuodostajan valkaisuteho verrattuna perinteisiin kompleksinmuodostajiin. Laboratoriossa suoritetut pesukokeet osoittivat, että mikään biohajoava kompleksinmuodostaja ei saavuttanut samaa pesutehoa kuin perinteiset kompleksinmuodostajat. Valkaisukokeet kuitenkin osoittivat, että biohajoava kompleksinmuodostaja ISA pääsi hyvin lähelle perinteisten kompleksinmuodostajien valkaisutuloksia suoritettaessa valkaisu siten, että massa esipestään kompleksinmuodostajalla ja sen jälkeen valkaistaan vakiokemikaaliannoksella alkalina ollessa natriumhydroksidi. Kaksi muuta biohajoavaa kompleksinmuodostajaa, ISA+EDDS ja HAS, eivät saavuttaneet samaa tasoa. HAS toimi kyllä stabilaattorina, muttei pystynyt nostamaan massan vaaleutta.

Novel Proteins Involved in Dynamics of The Photosynthetic Apparatus

During the past few years, a considerable number of research articles have been published relating to the structure and function of the major photosynthetic protein complexes, photosystem (PS) I, PSII, cytochrome (Cyt) b6f, and adenosine triphosphate (ATP) synthase. Sequencing of the Arabidopsis thaliana (Arabidopsis) genome together with several high-quality proteomics studies has, however, revealed that the thylakoid membrane network of plant chloroplasts still contains a number of functionally unknown proteins. These proteins may have a role as auxiliary proteins guiding the assembly, maintenance, and turnover of the thylakoid protein complexes, or they may be as yet unknown subunits of the photosynthetic complexes. Novel subunits are most likely to be found in the NAD(P)H dehydrogenase (NDH) complex, the structure and function of which have remained obscure in the absence of detailed crystallographic data, thus making this thylakoid protein complex a particularly interesting target of investigation. In this thesis, several novel thylakoid-associated proteins were identified by proteomics-based methods. The major goal of characterization of the stroma thylakoid associated polysome-nascent chain complexes was to determine the proteins that guide the dynamic life cycle of PSII. In addition, a large protein complex of ≥ 1,000 kDa, residing in the stroma thylakoid, was characterized in greater depth and it was found to be a supercomplex composed of the PSI and NDH complexes. A set of newly identified proteins from Arabidopsis thylakoids was subjected to detailed characterization using the reverse genetics approach and extensive biochemical and biophysical analysis. The role of the novel proteins, either as auxiliary proteins or subunits of the photosynthetic protein complexes, was revealed. Two novel thylakoid lumen proteins, TLP18.3 and AtCYP38, function as auxiliary proteins assisting specific steps of the assembly/repair of PSII. The role of the 10-kDa thylakoid lumen protein PsbR is related to the optimization of oxygen evolution of PSII by assisting the assembly of the PsbP protein. Two integral thylakoid membrane proteins, NDH45 and NDH48, are novel subunits of the chloroplast NDH complex. Finally, the thylakoid lumen immunophilin AtCYP20-2 is suggested to interact with the NDH complex, instead of PSII as was hypothesized earlier.

Electrochemical Characterisation of Filter Media Properties and Their Exploitation in Enhanced Filtration

Streaming potential measurements for the surface charge characterisation of different filter media types and materials were used. The equipment was developed further so that measurements could be taken along the surfaces, and so that tubular membranes could also be measured. The streaming potential proved to be a very useful tool in the charge analysis of both clean and fouled filter media. Adsorption and fouling could be studied, as could flux, as functions of time. A module to determine the membrane potential was also constructed. The results collected from the experiments conducted with these devices were used in the study of the theory of streaming potential as an electrokinetic phenomenon. Several correction factors, which are derived to take into account the surface conductance and the electrokinetic flow in very narrow capillaries, were tested in practice. The surface materials were studied using FTIR and the results compared with those from the streaming potentials. FTIR analysis was also found to be a useful tool in the characterisation of filters, as well as in the fouling studies. Upon examination of the recorded spectra from different depths in a sample it was possible to determine the adsorption sites. The influence of an external electric field on the cross flow microflltration of a binary protein system was investigated using a membrane electroflltration apparatus. The results showed that a significant improvement could be achieved in membrane filtration by using the measured electrochemical properties to help adjust the process conditions.

Community-acquired pneumonia in adult patients with special reference to rapid methods for etiological diagnosis

Aikuispotilaan kotisyntyisen keuhkokuumeen etiologinen diagnostiikka mikrobiologisilla pikamenetelmillä Tausta. Keuhkokuume on vakava sairaus, johon sairastuu Suomessa vuosittain n. 60 000 aikuista. Huolimatta siitä, että taudin hoito on kehittynyt, siihen liittyy yhä merkittävä, 6-15%:n kuolleisuus. Alahengitystieinfektion aiheuttajamikrobien tunnistaminen on myös edelleen haasteellista. Tavoitteet. Tämän työn tavoitteena oli tutkia Turun yliopistollisessa keskussairaalassa hoidettujen aikuispotilaiden keuhkokuumeen etiologiaa sekä selvittää uusien mikrobiologisten pikamenetelmi¬en hyödyllisyyttä taudinaiheuttajan toteamisessa. Aineisto. Osatöiden I ja III aineisto koostui 384 Turun yliopistollisen keskussairaalaan infektio-osastolla hoidetusta keuhkokuumepotilaasta. Osatyössä I tutkittiin keuhkokuumeen aiheuttaja¬mikrobeja käyttämällä perinteisten menetelmien lisäksi antigeeniosoitukseen ja PCR-tekniikkaan perustuvia pikamenetelmiä. Osatyö II käsitti 231 potilaasta koostuvan alaryhmän, jossa tutkittiin potilaiden nielun limanäytteestä rinovirusten ja enterovirusten esiintyvyyttä. Osatyössä III potilailta tutkittiin plasman C-reaktiivisen proteiinin (CRP) pitoisuus ensimmäisten viiden sairaalahoitopäi¬vän aikana. Laajoja tilastotieteellisiä analyysejä käyttämällä selvitettiin CRP:n käyttökelpoisuutta sairauden vaikeusasteen arvioinnissa ja komplikaatioiden kehittymisen ennustamisessa. Osatyössä IV 68 keuhkokuumepotilaan sairaalaan tulovaiheessa otetuista näytteistä määritettiin neutrofiilien pintareseptorien ekspressio. Osatyössä V analysoitiin sisätautien vuodeosastoilla vuosina 1996-2000 keuhkokuumepotilaille tehtyjen keuhkohuuhtelunäytteiden laboratoriotutkimustulokset. Tulokset. Keuhkokuumeen aiheuttaja löytyi 209 potilaalta, aiheuttajamikrobeja löydettiin kaikkiaan 230. Näistä aiheuttajista 135 (58.7%) löydettiin antigeenin osoituksella tai PCR-menetelmillä. Suu¬rin osa, 95 (70.4%), todettiin pelkästään kyseisillä pikamenetelmillä. Respiratorinen virus todettiin antigeeniosoituksella 11.1% keuhkokuumepotilaalla. Eniten respiratorisia viruksia löytyi vakavaa keuhkokuumetta sairastavilta potilailta (20.3%). 231 keuhkokuumepotilaan alaryhmässä todettiin PCR-menetelmällä picornavirus 19 (8.2%) potilaalla. Respiratorinen virus löytyi tässä potilasryh¬mässä kaiken kaikkiaan 47 (20%) potilaalta. Näistä 17:llä (36%) löytyi samanaikaisesti bakteerin aiheuttama infektio. CRP-tasot olivat sairaalaan tulovaiheessa merkitsevästi korkeammat vakavaa keuhkokuumetta (PSI-luokat III-V) sairastavilla potilailla kuin lievää keuhkokuumetta (PSI-luokat I-II) sairastavilla potilailla (p <0.001). Yli 100 mg/l oleva CRP-taso neljän päivän kuluttua sairaa¬laan tulosta ennusti keuhkokuumeen komplikaatiota tai huonoa hoitovastetta. Neutrofiilien komple¬menttireseptorin ekspressio oli pneumokokin aiheuttamaa keuhkokuumetta sairastavilla merkitse¬västi korkeampi kuin influenssan aiheuttamaa keuhkokuumetta sairastavilla. BAL-näytteistä vain yhdessä 71:stä (1.3%) todettiin diagnostinen bakteerikasvu kvantitatiivisessa viljelyssä. Uusilla menetelmilläkin keuhkokuumeen aiheuttaja löytyi vain 9.8% BAL-näytteistä. Päätelmät. Uusilla antigeeniosoitus- ja PCR-menetelmillä keuhkokuumeen etiologia voidaan saada selvitettyä nopeasti. Lisäksi näitä menetelmiä käyttämällä taudin aiheuttajamikrobi löytyi huomattavasti suuremmalta osalta potilaista kuin pelkästään tavanomaisia menetelmiä käyttämällä. Pikamenetelmien hyödyllisyys vaihteli taudin vaikeusasteen mukaan. Respiratorinen virus löytyi huomattavan usein keuhkokuumetta sairastavilta potilailta, ja näiden potilaiden taudinkuva oli usein vaikea. Tulovaiheen korkeaa CRP-tasoa voidaan käyttää lisäkeinona arvioitaessa keuhkokuumeen vaikeutta. CRP on erityisen hyödyllinen arvioitaessa hoitovastetta ja riskiä komplikaatioiden ke¬hittymiseen. Neutrofiilien komplementtireseptorin ekspression tutkiminen näyttää lupaavalta pi¬kamenetelmältä erottamaan bakteerien ja virusten aiheuttamat taudit toisistaan. Antimikrobihoitoa saavilla potilailla BAL-tutkimuksen löydökset olivat vähäiset ja vaikuttivat hoitoon vain harvoin.

Adsorção de oligonucleotídeos em nanoemulsões obtidas por emulsificação espontânea

This paper describes the adsorption of an oligothymidylate (pdT16) on nanoemulsions obtained by spontaneous emulsification procedures. Formulations were composed by medium chain triglycerides, egg lecithin, glycerol, water (NE) and stearylamine (NE SA). After optimization of operating conditions, the mean droplet size was smaller than 255 nm. Adsorption isotherms showed a higher amount of pdT16 adsorbed on cationic NE SA (60 mg/g) compared to NE (20 mg/g). pdT16 adsorption was also evidenced by the inversion of the zeta-potential of NE SA (from +50 to -30 mV) and the morphology of oil droplets examined through transmission electron microscopy. The overall results showed the role of electrostatic interactions on the adsorption of pdT16 on the oil/water interface of nanoemulsions.

Determinação teórica das conformações mais estáveis da trealose em solução aquosa

In this work the most abundant trehalose conformers for the isolated molecule as well as for the water solvated system are selected. The theoretical tecniques employed are ab initio calculations in the gas phase and in aqueous solution using the PCM model. A conformational map is built for the glycosidic angles (phi and psi) and the search for the most abundant structures is explained. The final structures are validated by the agreement found between experimental and theoretical values for ³J H,C along the glycosidic linkage.

Thylakoid Protein Phosphorylation in Regulation of Photosynthesis

Once the seed has germinated, the plant is forced to face all the environmental changes in its habitat. In order to survive, plants have evolved a number of different acclimation systems. The primary reaction behind plant growth and development is photosynthesis. Photosynthesis captures solar energy and converts it into chemical form. Photosynthesis in turn functions under the control of environmental cues, but is also affected by the growth, development, and metabolic state of a plant. The availability of solar energy fluctuates continuously, requiring non-stop adjustment of photosynthetic efficiency in order to maintain the balance between photosynthesis and the requirements and restrictions of plant metabolism. Tight regulation is required, not only to provide sufficient energy supply but also to prevent the damage caused by excess energy. The very first reaction of photosynthesis is splitting of water into the form of oxygen, hydrogen, and electrons. This most fundamental reaction of life is run by photosystem II (PSII), and the energy required for the reaction is collected by the light harvesting complex II (LHCII). Several proteins of the PSII-LHCII complex are reversibly phosphorylated according to the energy balance between photosynthesis and metabolism. Thylakoid protein phosphorylation has been under extensive investigation for over 30 years, yet the physiological role of phosphorylation remains elusive. Recently, the kinases behind the phosphorylation of PSII-LHCII proteins (STN7 and STN8) were identified and the knockout mutants of these kinases became available, providing powerful tools to elucidate the physiological role of PSII-LHCII phosphorylation. In my work I have used the stn7 and stn8 mutants in order to clarify the role of PSII-LHCII phosphorylation in regulation and protection of the photosynthetic machinery according to environmental cues. I show that STN7- dependent PSII-LHCII protein phosphorylation is required to balance the excitation energy distribution between PSII and PSI especially under low light intensities when the excitation energy transfer from LHC to PSII and PSI is efficient. This mechanism differs from traditional light quality-induced “state 1” – “state 2” transition and ensures fluent electron transfer from PSII to PSI under low light, yet having highest physiological relevance under fluctuating light intensity. STN8-dependent phosphorylation of PSII proteins, in turn, is required for fluent turn-over of photodamaged PSII complexes and has the highest importance upon prolonged exposure of the photosynthetic apparatus to excess light.

Estabilização do ácido lipoico via encapsulação em nanocápsulas poliméricas planejadas para aplicação cutânea

This work reports the development of polymeric nanocapsules containing lipoic acid prepared by interfacial deposition of poli(ε-caprolactona). The suspensions showed acid pH and encapsulation efficiencies from 77 to 90%. Zeta potential values were from -7.42 to -5.43 mV and particle sizes were lower than 340 nm with polidispersion lower than 0.3. The stability of nanocapsules within 28 days was evaluated in terms of pH, lipoic acid content, diameter, size distribution, zeta potential and measurements of relative light backscattering. The stability of formulations containing free lipoic acid was also evaluated. Nanoencapsulation drastically improved the physico-chemical stability of lipoic acid.

Desenvolvimento e caracterização de nanocápsulas de poli (L-lactídeo) contendo benzocaína

In this paper we describe the preparation poly (L-lactide) (PLA) nanocapsules as a drug delivery system for the local anesthetic benzocaine. The characterization and in vitro release properties of the system were investigated. The characterization results showed a polydispersity index of 0.14, an average diameter of 190.1± 3 nm, zeta potential of -38.5 mV and an entrapment efficiency of 73%. The release profile of Benzocaine loaded in PLA nanocapsules showed a significant different behavior than that of the pure anesthetic in solution. This study is important to characterize a drug release system using benzocaine for application in pain treatment.

Nanopartículas de alginato como sistema de liberação para o herbicida clomazone

In this paper, we describe the preparation of alginate nanoparticles as a delivery system for the herbicide clomazone. Two different methods were investigated and characterized by size distribution, zeta potencial, pH and in vitro release. The alginate/AOT nanoparticles had higher rates of association of the herbicide clomazone than alginate/chitosan nanoparticles. Clomazone release profile, showed a significant difference in release behavior of pure herbicide in solution when compared with herbicide loaded in both alginate nanoparticles. This study is important to construct a biodegradable release system using herbicide for later release into more specific targets, avoiding contamination of environmental matrices.

Cargas superficiais da fração argila de solos influenciadas pela vinhaça e fósforo

Effects of vinasse, P sorption and the interaction vinasse-phosphorus on zeta potential and point of zero charge (PZC) as well as the effects of vinasse on P sorption on clay-fraction samples from two soils were evaluated. The vinasse and P sorption influenced the surface charge of clay fraction of both soils. Sorption of P increased negative charges from soil particles reducing PZC. These effects were more pronounced when clay fraction was previously treated with vinasse. Vinasse treatment reduced P sorption, probably due to coating of P-adsorption sites and by enhancing the negative charges.

Preparação e caracterização de suspensões coloidais de nanocarreadores lipídicos contendo resveratrol destinados à administração cutânea

Solid lipid nanoparticles (SLN), nanoemulsions (NE), and microemulsions (ME) were prepared by the hot solvent diffusion method, using tristearin or castor oil as oily phase, and soy lecithin and Solutol HS 15 as surfactants. Mean particle sizes ranged from 20 to 215 nm and negative zeta potentials were obtained for all nanocarriers. A HPLC method used to determine resveratrol was specific, linear, exact and precise. The entrapment efficiency was high for all formulations. However, resveratrol content was significantly varied among the lipid nanocarriers. Lipid nanocarrier containing hydrogels exhibiting pseudoplastic behavior were obtained after incorporation of hydroxyethylcellulose in the colloidal dispersions.

Encapsulation of naproxen in nanostructured system: structural characterization and in vitro release studies

Nanoparticles were produced by solvent emulsification evaporation method with the following characteristics: nanometric size (238 ± 3 nm), narrow polydispersity index (0.11), negative zeta potential (-15.1 mV), good yield of the process (73 ± 1.5%), excellent encapsulation efficiency (81.3 ± 4.2%) and spherical shape. X-rays diffraction demonstrated the loss of drug crystallinity after encapsulation; however, the profile of the diffractograms of the poly-ε-caprolactone (PCL) nanoparticles was kept. Differential scanning calorimetry thermograms, correspondingly, exhibited the loss of drug melting peak and the increasing of the melting point of the PCL nanoparticles, evidencing an interaction drug-polymer. Naproxen release was low and sustained obeying the Higuchi´s kinetic. The results show that nanoparticles are promising sustained release system to the naproxen.