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1
Absorption Ångström exponents of aerosols and light absorbing carbon (LAC) obtained from in situ data in Covilhã, central Portugal
Publicaçãopor Mogo, SandraOutros Autores: Cachorro, Victoria; de Frutos, Ángel M; Rodrigues, A.Origem: uBibliorumA field campaign was conducted from October 2009 to July 2010 at Covilhã, a small town located in the region of Beira Interior (Portugal) in the interior of the Iberian Peninsula. The ambient light-absorption coefficient, σ(a) (522 nm), obtained from a Particle Soot Absorption Photometer (PSAP), presented a daily mean value of 12.1 Mm⁻¹ (StD = 7.3 Mm⁻¹). The wavelength dependence of aerosol light absorption is investigated through the Ångström parameter, α(a). The α(a) values for the pair of wavelengths 470-660 nm ranged from 0.86 to 1.47 during the period of measurements. The PSAP data were used to infer the mass of light absorbing carbon (LAC) and the daily mean varied from 0.1 to 6.8 μg m⁻³. A detailed study of special events with different aerosol characteristics is carried out and, to support data interpretation, air masses trajectory analysis is performed. -
2
Preparation of well-defined brush-like block copolymers for gene delivery applications under biorelevant reaction conditions
Publicaçãopor Góis, Joana R.Outros Autores: Reis, Fábio; Almeida, Ana Margarida; Pereira, Patrícia; Sousa, Fani; Serra, Armenio et al.Origem: uBibliorumWell-defined oligo(ethylene glycol) methyl ether methacrylate (OEOMA) based block copolymers with cationic segments composed by N,N-(dimethylamino) ethyl methacrylate (DMAEMA) and/or 2-(diisopropylamino) ethyl methacrylate (DPA) were developed under biorelevant reaction conditions. These brush-type copolymers were synthesized through supplemental activator and reducing agent (SARA) atom transfer radical polymerization (ATRP) using sodium dithionite as SARA agent. The synthesis was carried out using an eco-friendly solvent mixture, very low copper catalyst concentration, and mild reaction conditions. The structure of the block copolymers was characterized by size exclusion chromatography (SEC) analysis and 1H nuclear magnetic resonance (NMR) spectroscopy. The pH-dependent protonation of these copolymers enables the efficient complexation with plasmid DNA (pDNA), yielding polyplexes with sizes ranging from 200 up to 700 nm, depending on the molecular weight of the copolymers, composition and concentration used. Agarose gel electrophoresis confirmed the successful pDNA encapsulation. No cytotoxicity effect was observed, even for N/P ratios higher than 50, for human fibroblasts and cervical cancer cell lines cells. The in vitro cellular uptake experiments demonstrated that the pDNA-loaded block copolymers were efficiently delivered into nucleus of cervical cancer cells. The polymerization approach, the unique structure of the block copolymers and the efficient DNA encapsulation presented can open new avenues for development of efficient tailor made gene delivery systems under biorelevant conditions. -
3
Use of cork granules as an effective sustainable material to clean-up spills of crude oil and derivatives
Publicaçãopor Todescato, DiegoOutros Autores: Hackbarth, Fabíola V.; Carvalho, Pedro J.; Souza, Antônio A. Ulson de; Souza, Selene M A. G. Ulson de; Boaventura, Rui A. R. et al.The use of cork granules for cleaning up crude oil or oil derivative spills and further oil recovery appears as a promising option due to their unique properties, which allow a high oil sorption capacity, low water pickup and excellent reuse. The present work reports the effect of oil viscosity on cork sorption capacity by using five types of oils (lubricating oil, 5.7 goil gcork-1; heavy oil, 4.2 goil gcork-1; light oil, 3.0 goil gcork-1; biodiesel, 2.6 goil gcork-1; and diesel, 2.0 goil gcork-1). The cork sorption capacity for light petroleum was also evaluated as a function of temperature and sorbent particle size. Additionally, improvements on oil recovery from cork sorbents by a mechanical compression process have been achieved as a result of a design of experiments (DOE) using the response surface methodology. Such statistical technique provided remarkable results in terms of cork sorbent reusability, as the oil sorption capacity was preserved after 30 cycles of sorption-squeezing steps. The sorbed oils could be removed from the sorbent surface, collected simply by squeezing the cork granules and further reused. The best operational region yielded near 80% oil recovery, using a cork mass of 8.85 g (particle size of 2.0-4.0 mm) loaded with 43.5 mL of lubricating oil, at 5.4 bar, utilising two compressions with a duration of 2 min each. Graphical abstract. -
4
Prostatic Artery Embolization for Benign Prostatic Hyperplasia: Prospective Randomized Trial of 100-300 μm versus 300-500 μm versus 100- to 300-μm + 300- to 500-μm Embospheres....
Publicaçãopor Torres, DanielOutros Autores: Costa, Nuno V; Pisco, João; Pinheiro, Luis C; Oliveira, Antonio G; Bilhim, TiagoPurpose: This study compared the safety and efficacy of prostatic arterial embolization (PAE) with that of trisacryl gelatin microspheres of different sizes for treatment of benign prostatic hyperplasia (BPH). Materials and methods: This study consisted of a single-center, randomized controlled clinical trial in 138 patients who underwent PAE for BPH between July 2015 and December 2016. Patients were randomized to PAE using microspheres of different sizes: group A patients were treated with microspheres 100-300 μm, group B with 300-500 μm, and group C with 100-300 μm followed by 300-500 μm. All patients were evaluated before and at 1, 3, 6, 12, and 18 months after PAE. Baseline data were comparable across the 3 groups, using the following mean International Prostate Symptom Score/quality of life (IPSS/QoL); prostate volume (PV) scores, respectively: 23.0/4.14; 87.9 cm3 (group A); 23.0/4.09; 89.0 cm3 (group B); and 24.2/4.29; 81.0 cm3 (group C) (P > 0.05). Results: Mean IPSS/QoL scores; PV after PAE were: 9.98/2.49; 65.1 cm3 (group A); 8.24/2.26; 63.1 cm3 (group B); and 10.1/2.69; 53.1 cm3 (group C) (P = 0.23; P = 0.39; P = 0.24). There were 26 clinical failures. The cumulative probabilities of clinical success at 18 months were 76.7% in group A, 82.6% in group B, and 83.3% in group C (P = 0.68). Nontarget embolization was prevented in 6 patients by coil embolization. All adverse events were mild and self-limited with rates of 86.0% in group A (37 of 43); 41.3% in group B (19 of 46); and 58.3% in group C (28 of 48) (P < 0.001). Dysuria was the most frequent adverse event (28 of 137 [20.4%]). Conclusions: PAE outcomes were not significantly different among microspheres of different sizes. The use of 100- to 300-μm microspheres was associated with an increased risk of minor adverse events. -
5
Insights into the protective role of solid lipid nanoparticles on rosmarinic acid bioactivity during exposure to simulated gastrointestinal conditions
Publicaçãopor Madureira, Ana RaquelOutros Autores: Campos, Débora A.; Oliveira, Ana L.; Sarmento, Bruno; Pintado, M. E.; Gomes, Ana M. P.The evaluation of the digestion effects on bioactive solid lipid nanoparticles (SLN) was performed. For this purpose, witepsol and carnauba SLN loaded with rosmarinic acid (RA) were exposed to the simulated gastrointestinal tract (GIT) conditions prevailing in stomach and small intestine. The simulation of intestinal epithelium was made with a dialysis bag and intestinal cell culture lines. Changes on SLN physical properties, RA release and absorption profiles were followed at each step. Combination of digestion pH and enzymes showed a significant effect upon SLN physical properties. Zeta potential values increased at stomach conditions and decreased at small intestine simulation. Also, at intestine, SLN increased their sizes and released 40-60% of RA, maintaining its initial antioxidant activity values. Sustained release of 40% of RA from SLN was also observed in dialysis tube. At CaCo-2 cell line, both types of SLN showed similar absorbed RA % (ca. 30%). Nevertheless, in CaCo-2/HT29x mix cell lines, for carnauba SLN a lower adsorption RA % was observed than for witepsol SLN. Solid lipid nanoparticles protected RA bioactivity (in terms of antioxidant activity) until reaching the intestine. A controlled release of RA from SLN was achieved and a significant absorption was observed at intestinal cells. Overall, SLN produced with witepsol showed a higher stability than carnauba SLN. -
6
Effect of surface treatments on the bond strength of a resin cement to commercially pure titanium
Publicaçãopor de Almeida-Júnior, Antonio AlvesOutros Autores: Fonseca, Renata Garcia; Haneda, Isabella Gagliardi; Abi-Rached, Filipe de Oliveira; Adabo, Gelson LuisOrigem: OasisbrInvestigation of the effectiveness of surface treatments that promote a strong bond strength of resin cements to metals can contribute significantly to the longevity of metal-ceramic restorations. This study evaluated the effect of surface treatments on the shear bond strength (SBS) of a resin cement to commercially pure titanium (CP Ti). Ninety cast CP Ti discs were divided into 3 groups (n=30), which received one of the following airborne-particle abrasion conditions: (1) 50 μm Al2O3 particles; (2) 30 μm silica-modified Al2O3 particles (Cojet Sand); (3) 110 μm silica-modified Al2O3 particles (Rocatec). For each airborne-particle abrasion condition, the following post-airborne-particle abrasion treatments were used (n=10): (1) none; (2) adhesive Adper Single Bond 2; (3) silane RelyX Ceramic Primer. RelyX ARC resin cement was bonded to CP Ti surfaces. All specimens were thermally cycled before being tested in shear mode. Failure mode was determined. The best association was Rocatec plus silane. All groups showed 100% adhesive failure. There were combinations that promote higher SBS than the protocol recommended by the manufacturer of RelyX ARC. -
7
Evaluation of bone ingrowth into porous titanium implant: Histomorphometric analysis in rabbits
Publicaçãopor de Vasconcellos, Luana Marotta ReisOutros Autores: Leite, Daniel Oliveira; de Oliveira, Fernanda Nascimento; Carvalho, Yasmin Rodarte; Cairo, Carlos Alberto AlvesOrigem: OasisbrA porous material for bone ingrowth with adequate pore structure and appropriate mechanical properties has long been sought as the ideal bone-implant interface. This study aimed to assess in vivo the influence of three types of porous titanium implant on the new bone ingrowth. The implants were produced by means of a powder metallurgy technique with different porosities and pore sizes: Group 1 = 30% and 180 μm; Group 2 = 30% and 300 μm; and Group 3 = 40% and 180 μm. Six rabbits received one implant of each type in the right and left tibiae and were sacrificed 8 weeks after surgery for histological and histomor-phometric analyses. Histological analysis confirmed new bone in contact with the implant, formed in direction of pores. Histomorphometric evaluation demonstrated that the new bone formation was statistically significantly lower in the group G1 than in group G3, (P = 0.023). Based on these results, increased porosity and pore size were concluded to have a positive effect on the amount of bone ingrowth. -
8
Blends of cross-linked high amylose starch/pectin loaded with diclofenac
Publicaçãopor Soares, Grazielle ArantesOutros Autores: Castro, Ana Doris de; Cury, Beatriz S.F.; Evangelista, Raul CesarOrigem: OasisbrPolymers blends represent an important approach to obtain materials with modulated properties to reach different and desired properties in designing drug delivery systems in order to fulfill therapeutic needs. The aim of this work was to evaluate the influence of drug loading and polymer ratio on the physicochemical properties of microparticles of cross-linked high amylose starch-pectin blends loaded with diclofenac for further application in controlled drug delivery systems. Thermal analysis and X-ray diffractograms evidenced the occurrence of drug-polymer interactions and the former pointed also to an increase in thermal stability due to drug loading. The rheological properties demonstrated that drug loading resulted in formation of weaker gels while the increase of pectin ratio contributes to origin stronger structures. © 2012 Elsevier Ltd. -
9
Scanning electron microscopic and profilometric study of different sharpening stones
Publicaçãopor Andrade Acevedo, Roberto AntonioOutros Autores: Cardozo, Ana Karina Veloso; Sampaio, José Eduardo CésarOrigem: OasisbrScaling and root planing contribute to the recovery of periodontal health. All periodontal instruments loose their fine cutting angle after use. To maintain this angle, correct sharpening is required using specifically designed stones. The characteristics of sharpening stones can be compared to the blade of the instruments and also transported to root surface during instrumentation. Root smoothness is related to the quality of the blade. Therefore, the purpose of this study was to evaluate the characteristics of 9 sharpening stones by scanning electron microscopic and profilometric analyses. Ceramic and Neumar stones were very fine and both may be recommended to maintain the sharpness of the instruments. Arkansas, Thompson and CE stones presented greater roughness with very regular and round particles, and are suitable for maintenance of the cutting angle. In addition, these stones may be indicated for the routine sharpening of the instruments that are partly dull. Oxide Aluminum, Carborundum and JON stones were the coarsest with large irregular particles and may be indicated for initial sharpening of totally dull instruments with completion of sharpening with finer stones. -
10
Synthesis by wet chemical method of different phases of apatites applying ultrasound
Publicaçãopor Rodriguez-Chanfrau, Jorge E.Outros Autores: Garcia Pelizaro, Thales A.; Da Silva, Ricardo Moutinho; Tolaba, Angel G.; Pizoni, Elizabeth; Veranes-Pantoja, Yaymarilis et al.Origem: OasisbrCalcium phosphates have been widely used in medical, orthopedic and dental applications as materials for the replacement and repair of bone tissue or as implants coatings. Hydroxyapatite (HA), one of the phases of the Apatite, is one of the most used material for these applications due to its bioactivity and biocompatibility and similarity with the mineral phase of the human bone. One of the most widely methods used in calcium phosphate synthesis is the wet method, which allows to modify the physical chemical properties of the HA through the adjust of technical parameter of the method. The aim of this work was to study the influence of ultrasound during the maturation stage of the synthesis process. The obtained samples were characterized by X-ray Powder Diffraction, FTIR spectroscopy and Scanning Electron Microscopy. Particle size by scanning electron microscopy was determined. The calcium content by atomic absorption spectrometry was determined. The absorption/ desorption isotherms were determined by the method of nitrogen adsorption surface area, and the porosity was determined. The obtained results were compared with the results obtained in the synthesis without applying ultrasound. In this work ACP, TCP and OCP calcium phosphate were obtained by a wet reaction, without and with application of ultrasound. All samples shown isotherms adsorption/desorption characteristic of mesoporous materials. The samples treated with ultrasound have smaller particle size, smaller pore size and smaller surface area than samples obtained without ultrasound application.
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