Engineered MRI nanoprobes based on superparamagnetic iron oxide nanoparticles

This project aimed to engineer new T2 MRI contrast agents for cell labeling based on formulations containing monodisperse iron oxide magnetic nanoparticles (MNP) coated with natural and synthetic polymers. Monodisperse MNP capped with hydrophobic ligands were synthesized by a thermal decomposition method, and further stabilized in aqueous media with citric acid or meso-2,3-dimercaptosuccinic acid (DMSA) through a ligand exchange reaction. Hydrophilic MNP-DMSA, with optimal hydrodynamic size distribution, colloidal stability and magnetic properties, were used for further functionalization with different coating materials. A covalent coupling strategy was devised to bind the biopolymer gum Arabic (GA) onto MNPDMSA and produce an efficient contrast agent, which enhanced cellular uptake in human colorectal carcinoma cells (HCT116 cell line) compared to uncoated MNP-DMSA. A similar protocol was employed to coat MNP-DMSA with a novel biopolymer produced by a biotechnological process, the exopolysaccharide (EPS) Fucopol. Similar to MNP-DMSA-GA, MNP-DMSA-EPS improved cellular uptake in HCT116 cells compared to MNP-DMSA. However, MNP-DMSA-EPS were particularly efficient towards the neural stem/progenitor cell line ReNcell VM, for which a better iron dose-dependent MRI contrast enhancement was obtained at low iron concentrations and short incubation times. A combination of synthetic and biological coating materials was also explored in this project, to design a dynamic tumortargeting nanoprobe activated by the acidic pH of tumors. The pH-dependent affinity pair neutravidin/iminobiotin, was combined in a multilayer architecture with the synthetic polymers poy-L-lysine and poly(ethylene glycol) and yielded an efficient MRI nanoprobe with ability to distinguish cells cultured in acidic pH conditions form cells cultured in physiological pH conditions.

Erratum: Influence of oxygen plasma treatment parameters on poly(vinylidene fluoride) electrospun fiber mats wettability

Electrospun poly(vinylidene fluoride) (PVDF) fiber mats find applications in an increasing number of areas, such as battery separators, filtration and detection membranes, due to their excellent properties. However, there are limitations due to the hydrophobic nature and low surface energy of PVDF. In this work, oxygen plasma treatment has been applied in order to modify the surface wettability of PVDF fiber mats and superhydrophilic PVDF electrospun membranes have been obtained. Further, plasma treatment does not significantly influences fiber average size (~400 ± 200 nm), morphology, electroactive -phase content (~80-85%) or the degree of crystallinity (Xc of 42 ± 2%), allowing to maintain the excellent physical-chemical characteristics of PVDF. Plasma treatment mainly induces surface chemistry modifications, such as the introduction of oxygen and release of fluorine atoms that significantly changes polymer membrane wettability by a reduction of the contact angle of the polymer fibers and an overall decrease of the surface tension of the membranes.

A construção publicitária da herança da marca Burberry: uma proposta de análise

A herança das marcas de luxo é uma componente da marca (Aaker, 2004), construída numa dimensão intangível — do imaginário (Maffesoli, 2006), do mito, do desejo (Castarède, 2007) — e materializada em vários suportes de comunicação, entre estes, as imagens publicitárias em revistas de moda. Segundo vários autores (Kopnina, 2007; Morris & Nichols, 2013; Moulins & Roux, 2008), a herança das marcas de luxo é representada na publicidade através de uma linguagem simbólica que transmite os valores e emoções da marca, apela à dimensão sensitiva e afetiva dos consumidores e tenta seduzi-los e conquistá-los, articulando o passado, o presente e o futuro, a sua herança (Hill, 2006). No quadro de um projeto de investigação de doutoramento sobre o tema, pretende-se discutir o conceito de herança da marca e o papel da comunicação publicitária no processo de construção da mesma. O foco incide nas marcas de luxo de vestuário, dada a forte carga simbólica que define este segmento (Lipovetsky & Roux, 2005; Lipovetsky, 2007) e a importância vital da dimensão intangível neste setor (Hancock II et al. (Eds.), 2014; Husband & Chadha, 2007; Kapferer & Bastien, 2009a; Okonkwo, 2007; Tungate, 2009). Como suporte teórico para esta discussão, articulam-se saberes provenientes da gestão da marca, do marketing, da sociologia e da filosofia. Por ser uma marca que investe na construção da sua herança e na criação de produtos icónicos, nomeadamente o trench coat (Moore & Birtwistle, 2004), propomos ilustrar a nossa reflexão com o exemplo da marca britânica Burberry e das suas imagens publicitárias. Para o efeito, recorremos às últimas 4 imagens publicitárias da Burberry, publicadas na Vogue UK, por ser o país de origem da marca. Assim, iremos 1) analisar a herança da Burberry e o papel da trench coat nesta construção e no percurso da marca; 2) identificar, nas imagens, os elementos sígnicos que remetem para a herança da Burberry; 3) relacionar estes elementos com a história e o percurso da Burberry para compreender a forma como estas imagens fazem do trench coat um produto icónico da marca. Assim, este trabalho, no quadro do nosso projeto de investigação de doutoramento, permite-nos aprofundar conceitos e relações centrais na problemática tecida e testar caminhos para a sua exploração empírica.

Atividade fotossintética do bago de uva (Vitis vinifera, cv. Alvarinho) ao longo do desenvolvimento dos cachos em diferentes microambientes de luz

Dissertação de mestrado em Biologia Molecular, Biotecnologia e Bioempreendedorismo em Plantas

Gellan gum-coated gold nanorods: an intracellular nanosystem for bone tissue engineering

Gold nanorods (AuNRs) have emerged as an exceptional nanotool for a myriad of applications ranging from cancer therapy to tissue engineering. However, their surface modification with biocompatible and stabilizing biomaterials is crucial to allow their use in a biological environment. Herein, low-acyl gellan gum (GG) was used to coat AuNRs surface, taking advantage of its stabilizing, biocompatible and gelling features. The layer-by-layer based strategy implied the successive deposition of poly(acrylic acid), poly(allylamine hydrochloride) and GG, which allowed the formation of a GG hydrogel-like shell with 7 nm thickness around individual AuNRs. Stability studies in a wide range of pH and salt concentrations showed that the polysaccharide coating can prevent AuNRs aggregation. Moreover, a reversible pH-responsive feature of the nanoparticles was observed. Cytocompatibility and osteogenic ability of GG-coated AuNRs was also addressed. After 14 days of culturing within SaOS-2, an osteoblast-like cell line, in vitro studies revealed that AuNRs-GG exhibit no cytotoxicity, were internalized by the cells and localized inside lysosomes. AuNRs-GG combined with osteogenic media enhanced the mineralization capacity two-fold, as compared to cells exposed to osteogenic media alone. The proposed system has shown interesting features for osteogenesis, and further insights might be relevant for drug delivery, tissue engineering and regenerative medicine.

Effect of chitosan-Aloe vera coating on postharvest quality of blueberry (Vaccinium corymbosum) fruit

The present study was carried out to evaluate the effect of chitosan-based edible coatings with Aloe vera extract on the postharvest blueberry fruit quality during storage at 5 °C. Firstly, A. vera fractions (pulp and liquid) were extracted from leaves and evaluated in terms of antifungal and antioxidant capacities. The choice of the most adequate chitosan and A. vera fraction concentrations to be incorporated in coating formulation was made based on the wettability of the corresponding coating solutions. Coatings with 0.5% (w/v) chitosan + 0.5% (w/v) glycerol + 0.1% (w/v) Tween 80 + 0.5% (v/v) A. vera liquid fraction presented the best characteristics to uniformly coat blueberry surface. Physico-chemical (i.e., titratable acidity, pH, weight loss) and microbiological analyses of coated blueberries (non-inoculated or artificially inoculated with Botrytis cinerea) were performed during 25 d. Microbiological growth and water loss levels were approximately reduced by 50% and 42%, respectively, in coated blueberries after 25 d compared to uncoated blueberries. After 15 d, weight loss values were 6.2% and 3.7% for uncoated and chitosanA. vera coated blueberries, respectively. Uncoated fruits presented mold contamination after 2 d of storage (2.0 ± 0.32 log CFU g1), whilst fruits with chitosan-based coatings with A. vera presented mold contamination only after 9 d of storage (1.3 ± 0.35 log CFU g1). Overall, coatings developed in this study extend blueberries shelf-life for about 5 d, demonstrating for the first time that the combination of chitosan and A. vera liquid fraction as edible coating materials has great potential in expanding the shelf-life of fruits.

Influence of Quality of Sleep on the Nocturnal Decline in Blood Pressure During Ambulatory Blood Pressure Monitoring

OBJECTIVE: To assess the influence of the quality of sleep on the nocturnal physiological drop in blood pressure during ambulatory blood pressure monitoring. METHODS: We consecutively assessed ambulatory blood pressure monitoring, the degree of tolerance for the examination, and the quality of sleep in 168 patients with hypertension or with the suspected "white-coat" effect. Blood pressure fall during sleep associated with a specific questionnaire and an analogical visual scale of tolerance for ambulatory blood pressure monitoring were used to assess usual sleep and sleep on the day of examination. Two specialists in sleep disturbances classified the patients into 2 groups: those with normal sleep and those with abnormal sleep. RESULTS: Fifty-nine (35 %) patients comprised the abnormal sleep group. Findings regarding the quality of sleep on the day of ambulatory blood pressure monitoring as compared with those regarding the quality of sleep on a usual day were different and were as follows, respectively: total duration of sleep (-12.4±4.7 versus -42.2±14.9 minutes, P=0.02), latency of sleep (0.4±2.7 versus 17±5.1 minutes, P<0.001), number of awakenings (0.1±0.1 versus 1.35±0.3 times, P<0.001), and tolerance for ambulatory blood pressure monitoring (8±0.2 versus 6.7±0.35, P=0.035). An abnormal drop in blood pressure during sleep occurred in 20 (18%) patients in the normal sleep group and in 14 (24%) patients in the abnormal sleep group, P=0.53. CONCLUSION: Ambulatory blood pressure monitoring causes sleep disturbances in some patients, and a positive association between quality of sleep and tolerance for the examination was observed.

Development of nanohydrogels as a vehicle for the release of bioactive compounds in food matrices

PhD in Chemical and Biological Engineering

Ambulatory Blood Pressure Monitoring: Five Decades of More Light and Less Shadows

Abstract Casual blood pressure measurements have been extensively questioned over the last five decades. A significant percentage of patients have different blood pressure readings when examined in the office or outside it. For this reason, a change in the paradigm of the best manner to assess blood pressure has been observed. The method that has been most widely used is the Ambulatory Blood Pressure Monitoring - ABPM. The method allows recording blood pressure measures in 24 hours and evaluating various parameters such as mean BP, pressure loads, areas under the curve, variations between daytime and nighttime, pulse pressure variability etc. Blood pressure measurements obtained by ABPM are better correlated, for example, with the risks of hypertension. The main indications for ABPM are: suspected white coat hypertension and masked hypertension, evaluation of the efficacy of the antihypertensive therapy in 24 hours, and evaluation of symptoms. There is increasing evidence that the use of ABPM has contributed to the assessment of blood pressure behaviors, establishment of diagnoses, prognosis and the efficacy of antihypertensive therapy. There is no doubt that the study of 24-hour blood pressure behavior and its variations by ABPM has brought more light and less darkness to the field, which justifies the title of this review.

Riqueza em óleo nas sementes, amêndoas e cascas das bagas de mamona

This paper is a joined publication of the Depts. of Genetics and of Technology, of the E. S. A. "Luiz de Queiroz", Universidade de São Paulo, and deals with the variation of the percentage oil content in the whole seeds, the embryos and the seed-coat of 28 varieties of castor-beans (Ricinus communis, L.). Primarily, the authors, as a justification of this paper, make reference to the applications which castor-oil has in industry, medicine, etc. In accordance with the weight of 100 seeds, the varieties of castor-beans were classified into 3 classes : small seeds (100 seeds less than 30 g), medium seeds (100 seeds between 30 g and 60) and large seeds (100 seeds more than 60 g). The percentage of oil in the seed, embryo and seed-coat, the dimensions of the seeds and the weight of 100 seeds are given for every variety in table 1. In order to obtain an estimate of the variability for the methods of determination of the oil percentage, in the 3 differents parts of the seeds and also in the 3 groups of seeds, the coefficient of variability was calculate (table 2). It is showed that the variation in the seed and embryo is low and that in the seed-coat is very high. The analysis of variance, with regard to the difference among the 3 types of seeds (small, medium and large), among the 3 parts of the seed (whole seed, embryo and seed-coat) and residual error, is given in table 3. Only, the oil content of whole seeds among types of seeds was significant at the 5% level. The t test among the correspondent means is not significant for the difference between medium and large seeds is significant between both these types (medium and large) and small seeds. The fiducial limits in relation to the mean of the oil percentage in the 3 differents types of seed, show that there is one variety (n. 1013-2), which has a percentage of oil, in the medium type of seed, significantly at the 5% level (table 4), higher than the general mean. Since the distribution of the percentage of oil in the seedcoat is discontinuous, 5 groups were established (table 5). All the differences between groups are significant (table 6). For practical purposes, when we have to remove the seed coat, one should eliminate those varieties which loose at least 3% of oil by this procedure. There is a significant linear correlation at 5% level between the percentage of oil in the seed and in the embryo, of the smali and medium type of seeds (table 7), and also, when taking the 3 types together (lower part of table 7), one finds that the same is true. Also, the correlation between the percentages of oil in the embryo and in the seed-coat of the 3 types together is significant at 5% level. According to the results obtained in relation to the percentage in 28 varieties studied, it can be recommended, for breeding purposes, to work only with those varieties which belong to the medium and the large types of seeds.

Alterações patológicas do apêndice vermiforme contendo Proglottis de Taenia sp

Pathological changes in the vermiform appendix harbouring tapeworm's proglottides are reported. Marked local (tissue) eosinophilia in the stroma of the mucous coat and to a less degree in the sub-mucosa and around the vessels in the inner circular layer of the muscular coat is the essential change observed. Peculiar changes such as an striking increase in the volume of the mucus-producing goblet-cells either in the epithelium covering the free surface or in the glands of Lieberkühn, as well as new epithelium atypical in form and arrangement were noticed in direct connection and likely induced by the tapeworn as a foreign body (mechanical injury). The local (tissue) eosinophilia probably represents an anaphylactoid response to foreign proteins originating in the tapeworm. Acute appendicitis in its recognized varieties such as appendicitis superficalis catarrhalis, a. s. exulcerans, a. s. haemorrhagica, a. phlegmonosa, and a. phlegmonosa-ulcerosa could be microscopically excluded. It seems, however, that local (tissue) eosinophilia when particularly widespread is able to give clinical symtoms suggestive of acute appendicitis.

Diagnóstico rápido de citomegalovirus (CMV) en pacientes inmunocomprometidos mediante anticuerpos monoclonales que reconocen proteinas precoces virales

Se aplicó la técnica de detección de antigenos precoces fluorescentes (DAPF) usando el anticuerpo monoclonal E-13 McAb, mediante el cual se lograron detectar 15 casos positivos a CMV de 75 muestras de orina o sangre ("buffy coat") tomadas de 52 pacientes inmunocomprometidos ingresados en el Instituto de Nefrología de ciudad Habana. Aplicando las técnicas clásicas de aislamiento en fibroblastos humanos diploides (MRC-5), se lograron aislar 12 cepas de CMV de casos previamente positivos por DAPF; lográndose además un aislamiento en una muestra reportada negativa por fluorescencia. Se observó una coincidencia de un 80% entre ambas técnicas. Se detectó la presencia de anticuerpos IgG contra CMV en todos los casos estudiados, utilizando para ello la técnica ELISA.

Biomphalaria obstructa (Morelet, 1849): a study of topotypic specimens (Mollusca: pulmonata: planorbidae)

A description of Biomphalaria obstructa (Morelet, 1849), based on specimens collected at its type locality - isla del carmen, state of Campeche, Mexico - is presented. The Shell is small, 13 mm in diameter, 3.5 mm in width and with 5.75 whorls in the largest specimen, thin, moderately lustrous and translucent, horn-colored. Whorls increasing regularly (neither slowly nor rapidly) in diameter, rounded on the periphery side, bluntly angular on the left. Suture well-marked, deeper on the left. Right side widely concave, with first whorl deeply situated and partly hidden by the next. Left side shallower than right one, largely flattened, with first whorl plaintly visible. Aperture roundly heart-shaped, usually in the same plane as the body whorl but somewhat deflected to the left (less frequently to the right) in some specimens. Peristome sharp, seldom blunt; a distinct callus on the parietal wall. A number of young shells develop one set (seldom more) of apertural lamellae which tend to be resorbed as the shell grows. Absence of renal ridge. Ovotestis with about 70 mostly unbrached diverticula. Seminal vesicle beset with well-developed knoblike to fingerlike diverticula. Vaginal pouch more or less developed. Spermatheca club-shaped when empty, egg-shaped when full, and with intermediate forms between those extremes. Spermathecal body usually somewhat longer than the duct. Prostate with 7 to 20 (mean 12.06 ± 2.51) usually short diverticula which give off plumpish branches spreading out in a fan shape and overlapping to some extent their immediate neighbors. Foremost prostatic diverticulum nearly always partially or completely inserted between the spermathecal body and the uterine wall. Penial sheath consistently narrower and shorter than the prepuce. Muscular coat of the penis consisting of an inner longitudinal and an outer circular layers. Ratios between organ lengths: caudal to cephalic parts of female duct = 0.55 to 1.37 (mean 0.85 +- 0.17); cephalic parte of female duct to penial complex = 1.36 to 2.81 ((mean 1.90 +- 0.33); penial sheath to prepuce = 042 to 0.96 (mean 0.67 +- 0.13). Comparison with Morelet’s type specimens of Planorbis orbiculus and P. retusus points to the identity of those nominal species with B. obstructa.

Sulphate-reducing bacteria associated with biocorrosion: a review

Biocorrosion means any process of corrosion in wich microorganisms are somehow involved. As far as the petroleum industry is concerned, the anaerobic type is the more important, with Sulphate-Reducing Bacteria (SRB) accouting for half of the described processes. SRB are obligate anaerobs that use sulphur, sulphate or other oxidized sulphur compounds as oxidizing agents when decomposing organic material. A typical product of SRB metabolism, hydrogen sulphide -H2S-, is extremely toxic. In the present work we review the literature on mechanisms underlying biocorrosive process in wich SRB are involved and summarize some of the ultrastructural and eletrochemical work developed using SRB obtained from water injection flow in wells located on PETROBRAS offshore marine plataforms, sampled directly in the field over metallic probes, or cultured under laboratory conditions. Biofilms develop when SRB adhere to inert surfaces. A high diversity of morphological types is found inside these biofilms. Their extracellular matrix is highly hydrated and mainly anionic, as shown by its avid reaction with cationic compounds like ruthenium red. We have noted that variations in iron contet lead to interesting changes in the ultrastructure of the bacterial cell coat and also in the rate of corrosion induced in metallic test cupons. Since routine methods to prevent and treat SRB contamination and biodeterioration involve the use of biocides that are toxic and always have some environmental impact, an accurate diagnosis of biocorrosion is always required prior to a treatment decision. We developed a method that detects and semi-quantifies the presence of living or dead SRB by using free silver potentials as an indicator of corrosive action by SRB-associated sulphides. We found a correlation between sulphide levels (determined either by spectrophotometry, or using a silver electrode -E(Ag)- that measured changes in free potentials induced by the presence of exogeneously added sulphide) and SRB concentration (enumerated by a culturing method). E (Ag) was characterized under a variety of conditions andwas found to be relatively immune to possible interference resulting from aeration of media or from the psence of iron corrosion products. The method offers a simple, rapid, and effective means of diagnosing biocorrosive processes prior to their control.

New inhibitors of Helicobacter pylori urease holoenzyme selected from phage-displayed peptide libraries.

Urease is an important virulence factor for Helicobacter pylori and is critical for bacterial colonization of the human gastric mucosa. Specific inhibition of urease activity has been proposed as a possible strategy to fight this bacteria which infects billions of individual throughout the world and can lead to severe pathological conditions in a limited number of cases. We have selected peptides which specifically bind and inhibit H. pylori urease from libraries of random peptides displayed on filamentous phage in the context of pIII coat protein. Screening of a highly diverse 25-mer combinatorial library and two newly constructed random 6-mer peptide libraries on solid phase H. pylori urease holoenzyme allowed the identification of two peptides, 24-mer TFLPQPRCSALLRYLSEDGVIVPS and 6-mer YDFYWW that can bind and inhibit the activity of urease purified from H. pylori. These two peptides were chemically synthesized and their inhibition constants (Ki) were found to be 47 microM for the 24-mer and 30 microM for the 6-mer peptide. Both peptides specifically inhibited the activity of H. pylori urease but not that of Bacillus pasteurii.