Highly-accessible, doped TiO₂ nanoparticles embedded at the surface of SiO₂ as photocatalysts for the degradation of pollutants under visible and UV radiation

A series of photocatalysts consisting of C- and N-doped titanium dioxide (TiO2) nanoparticles highly dispersed and firmly embedded at the surface of a silica matrix were prepared using a novel synthesis method in which activated carbon has a double role: it acts as support for depositing the TiO2 nanoparticles and as hard template for generating a silica matrix that embeds them. Additionally, the use of activated carbon in combination with ammonia during the synthesis led to carbon and nitrogen doping of the TiO2 domains, which enhanced their absorption of radiation in the visible range. The combination of these features led to higher activity (i.e. higher removal % and TON) in the photocatalytic degradation of probe pollutants (phenol and rhodamine B) compared to the benchmark P25 TiO2 under UV and, even more markedly, under visible radiation. Particularly, the photocatalyst prepared with 10 wt% of TiO2 nanoparticles (10%TiO2NP@SiO2) displayed much enhanced TON values under visible radiation compared to P25 TiO2 (a 12 times higher TON with rhodamine B, and an 8 times higher TON with phenol). The TON values are also significantly higher compared to any previously reported TiO2-SiO2 photocatalyst. The TiO2NP@SiO2 photocatalysts can be effectively reused in consecutive runs. The photocatalytic activity of the prepared materials was correlated to their physicochemical properties by means of a thorough characterisation using a combination of techniques (XRD, ICP-OES, N2 physisorption, TEM, UV–vis, FT-IR and XPS)

Insight into the prebiotic concept: lessons from an exploratory, double blind intervention study with inulin-type fructans in obese women

Objective To highlight the contribution of the gut microbiota to the modulation of host metabolism by dietary inulin-type fructans (ITF prebiotics) in obese women. Methods A double blind, placebo controlled, intervention study was performed with 30 obese women treated with ITF prebiotics (inulin/oligofructose 50/50 mix; n=15) or placebo (maltodextrin; n=15) for 3 months (16 g/day). Blood, faeces and urine sampling, oral glucose tolerance test, homeostasis model assessment and impedancemetry were performed before and after treatment. The gut microbial composition in faeces was analysed by phylogenetic microarray and qPCR analysis of 16S rDNA. Plasma and urine metabolic profiles were analysed by 1H-NMR spectroscopy. Results Treatment with ITF prebiotics, but not the placebo, led to an increase in Bifidobacterium and Faecalibacterium prausnitzii; both bacteria negatively correlated with serum lipopolysaccharide levels. ITF prebiotics also decreased Bacteroides intestinalis, Bacteroides vulgatus and Propionibacterium, an effect associated with a slight decrease in fat mass and with plasma lactate and phosphatidylcholine levels. No clear treatment clustering could be detected for gut microbial analysis or plasma and urine metabolomic profile analyses. However, ITF prebiotics led to subtle changes in the gut microbiota that may importantly impact on several key metabolites implicated in obesity and/or diabetes. Conclusions ITF prebiotics selectively changed the gut microbiota composition in obese women, leading to modest changes in host metabolism, as suggested by the correlation between some bacterial species and metabolic endotoxaemia or metabolomic signatures

Uma Contribuição ao Modelamento Analítico em Amplificadores Raman

Os atuais avanços na fabricação de lasers de alta potência e da tecnologia WDM despertaram o interesse em investir em amplificadores ópticos com banda larga, como os amplificadores Raman. A amplificação dos sinais em amplificadores Raman ocorre devido ao efeito não linear que surge nas transmissões de sinais em fibras ópticas, conhecido como espalhamento estimulado de Raman. Os amplificadores Raman apresentam uma amplificação distribuída, pois a transferência de energia ocorre ao longo de todo o comprimento do enlace. Um dos maiores desafios quando se trata de amplificadores Raman com multi-bombeios é conseguir ajustar o ganho e o ripple desejados em uma banda larga de sinais. Esta otimização é condicionada ao correto conjunto de bombeios, seus comprimentos de onda e suas potências, que é estabelecido ao sistema. Alguns métodos de otimização do ganho já foram propostos em trabalhos anteriores e grande parte deles recorre à solução numérica das equações acopladas que descrevem a evolução das potências em amplificadores Raman. Este trabalho desenvolve um modelo analítico com equações que descrevem a evolução das potências e conseqüentemente do ganho dos sinais propagantes em amplificadores Raman multi-bombeios e multi-sinais. O modelo analítico inclui a interação, devido ao efeito Raman, entre todos os comprimentos de onda propagantes e os efeitos de polarização, desconsiderando em sua formulação os efeitos de ruído de emissão espontânea amplificada e do espalhamento elástico da luz (espalhamento de Rayleigh). O modelo proposto é validado comparando os resultados analíticos com resultados obtidos através de soluções numéricas e com dados experimentais, considerando diversas configurações do amplificador. Os testes comparativos mostram que o modelo analítico desenvolvido neste trabalho é uma ferramenta bastante rápida e confiável que pode ser utilizada para projetar amplificadores Raman multi-sinais e multibombeios

Gut microbiota-derived propionate reduces cancer cell proliferation in the liver

Peer reviewedPublisher PD

MECP2 duplication syndrome: The electroclinical features of a case with long-term evolution

MECP2 duplication syndrome (MDS) is a rare and severe neurodevelopmental disorder frequently associated with epilepsy. Different seizure types and electroencephalographic (EEG) patterns were described in patients with MDS, although it lacks a specific phenotype. We report on an adult patient with long-term epilepsy showing an evolution of the EEG pattern that progressively changed into burst suppression (BS) during sleep. As BS has not been previously reported in MDS, this report expands the neurophysiological phenotype of MDS and further suggest the possible occurrence of a longitudinal spectrum of seizure types and EEG patterns in MDS

Preoperative cardiac risks in noncardiac surgery: The role of coronary angiography

The preoperative evaluation of patients candidates to noncardiac surgery requires a knowledge of factors related both to type of surgery and to features of the single patient, potentially responsible for perioperative cardiovascular complications, fatal and nonfatal. The assessment of symptoms and/or noninvasive testing indicating the presence of coronary artery disease may suggest the need for medical therapy optimization and, eventually, coronary arteriography before the scheduled timing of noncardiac surgery. There is no evidence favoring a prophylactic myocardial revascularization (percutaneous or surgical) and more studies are needed to define the role of coronary artery disease diagnosis and treatment before high-risk non cardiac surgery

Wheat-derived arabinoxylan oligosaccharides with prebiotic effect increase satietogenic gut peptides and reduce metabolic endotoxemia in diet-induced obese mice

BACKGROUND: Alterations in the composition of gut microbiota -known as dysbiosis- have been proposed to contribute to the development of obesity, thereby supporting the potential interest of nutrients acting on the gut microbes to produce beneficial effect on host energetic metabolism. Non-digestible fermentable carbohydrates present in cereals may be interesting nutrients able to influence the gut microbiota composition.OBJECTIVE AND DESIGN: The aim of the present study was to test the prebiotic potency of arabinoxylan oligosaccharides (AXOS) prepared from wheat bran in a nutritional model of obesity, associated with a low-grade chronic systemic inflammation. Mice were fed either a control diet or a high fat (HF) diet, or a HF diet supplemented with AXOS during 8 weeks.RESULTS: AXOS supplementation induced caecal and colon enlargement associated with an important bifidogenic effect. It increased the level of circulating satietogenic peptides produced by the colon (peptide YY and glucagon-like peptide-1), and coherently counteracted HF-induced body weight gain and fat mass development. HF-induced hyperinsulinemia and the Homeostasis Model Assessment of insulin resistance were decreased upon AXOS feeding. In addition, AXOS reduced HF-induced metabolic endotoxemia, macrophage infiltration (mRNA of F4/80) in the adipose tissue and interleukin 6 (IL6) in the plasma. The tight junction proteins (zonula occludens 1 and claudin 3) altered upon HF feeding were upregulated by AXOS treatment suggesting that the lower inflammatory tone was associated with the improvement of gut barrier function.CONCLUSION: Together, these findings suggest that specific non-digestible carbohydrates produced from cereals such as AXOS constitute a promising prebiotic nutrient in the control of obesity and related metabolic disorders.</p

Circulating fatty acids and endocannabinoidome-related mediator profiles associated to human longevity

To evaluate whether a peculiar plasma profile of fatty acids and endocannabinoidome (eCBome)-related mediators may be associated to longevity, we assessed them in octogenarians (Old; n=42) living in the east-central mountain area of Sardinia, a High-Longevity Zone (HLZ), compared to sexagenarian (Young; n=21) subjects from the same area, and to Olds (n=22) from the Northern Sardinia indicated as Lower-Longevity Zone (LLZ). We found significant increases in conjugated linoleic acid (CLA) and heptadecanoic acid (17:0) levels in Old-HLZ with respect to younger subjects and Old-LLZ subjects. Young-HLZ subjects exhibited higher circulating levels of pentadecanoic acid (15:0) and retinol. Palmitoleic acid (POA) was elevated in both Young and Old subjects from the HLZ. eCBome profile showed a significantly increased plasma level of the two endocannabinoids, N-arachidonoyl-ethanolamine (AEA) and 2-arachidonoyl-glycerol (2-AG) in Old-HLZ subjects compared to Young-HLZ and Old-LLZ respectively. In addition, we found increased N-oleoyl-ethanolamine (OEA), 2-linoleoyl-glycerol (2-LG) and 2-oleoyl-glycerol (2-OG) levels in Old-HLZ group with respect to Young-HLZ (as for OEA an d 2-LG) and both the Old-LLZ and Young-HLZ for 2-OG. The endogenous metabolite of docosahexaenoic acid (DHA), N-docosahexaenoyl-ethanolamine (DHEA) was significantly increased in Old-HLZ subjects. In conclusion, our results suggest that in the HLZ area, Young and Old subjects exhibited a favourable, albeit distinctive, fatty acids and eCBome profile that may be indicative of a metabolic pattern potentially protective from adverse chronic conditions. These factors could point to a suitable physiological metabolic pattern that may counteract the adverse stimuli leading to age-related disorders such as neurodegenerative and metabolic diseases

PROP1 and CTNNB1 expression in adamantinomatous craniopharyngiomas with or without β-catenin mutations

INTRODUCTION: Activating mutations in exon 3 of the &#946;-catenin gene are involved in the pathogenesis of adamantinomatous craniopharyngiomas. Recently, the interaction between &#946;-catenin and PROP1 has been shown to be responsible for pituitary cell lineage determination. We hypothesized that dysregulated PROP1 expression could also be involved in the pathogenesis of craniopharyngiomas OBJECTIVES: To determine whether dysregulated gene expression was responsible for tumor pathogenesis in adamantinomatous craniopharyngiomas, the &#946;-catenin gene was screened for mutations, and the expression of the &#946;-catenin gene and PROP1 was evaluated. &#946;-catenin gene was amplified and sequenced from 14 samples of adamantinomatous craniopharyngiomas. PROP1 and &#946;-catenin gene expression was assessed by real-time RT-PCR from 12 samples, and &#946;-catenin immunohistochemistry was performed on 11 samples. RESULTS: Mutations in the &#946;-catenin gene were identified in 64% of the adamantinomatous craniopharyngiomas samples. Evidence of &#946;-catenin gene overexpression was found in 71% of the tumors with &#946;-catenin mutations and in 40% of the tumors without mutations, and &#946;-catenin immunohistochemistry revealed a nuclear staining pattern for each of the analyzed samples. PROP1 expression was undetectable in all of the tumor samples. CONCLUSION: We found evidence of &#946;-catenin gene overexpression in the majority of adamantinomatous craniopharyngiomas, and we also detected a nuclear &#946;-catenin staining pattern regardless of the presence of a bcatenin gene mutation. These results suggest that WNT signaling activation plays an important role in the pathogenesis of adamantinomatous craniopharyngiomas. Additionally, this study was the first to evaluate PROP1 expression in adamantinomatous craniopharyngiomas, and the absence of PROP1 expression indicates that this gene is not involved in the pathogenesis of this tumor, at least in this cohort

Characterisation of Gut Microbiota in Ossabaw and Göttingen Minipigs as Models of Obesity and Metabolic Syndrome

Recent evidence suggests that the gut microbiota is an important contributing factor to obesity and obesity related metabolic disorders, known as the metabolic syndrome. The aim of this study was to characterise the intestinal microbiota in two pig models of obesity namely Göttingen minipigs and the Ossabaw minipigs.The cecal, ileal and colonic microbiota from lean and obese Osabaw and Göttingen minipigs were investigated by Illumina-based sequencing and by high throughput qPCR, targeting the 16S rRNA gene in different phylogenetic groups of bacteria. The weight gain through the study was significant in obese Göttingen and Ossabaw minipigs. The lean Göttingen minipigs' cecal microbiota contained significantly higher abundance of Firmicutes (P<0.006), Akkermensia (P<0.01) and Methanovibribacter (P<0.01) than obese Göttingen minipigs. The obese Göttingen cecum had higher abundances of the phyla Spirochaetes (P<0.03), Tenericutes (P<0.004), Verrucomicrobia (P<0.005) and the genus Bacteroides (P<0.001) compared to lean minipigs. The relative proportion of Clostridium cluster XIV was 7.6-fold higher in cecal microbiota of obese Göttingen minipigs as compared to lean. Obese Ossabaw minipigs had a higher abundance of Firmicutes in terminal ileum and lower abundance of Bacteroidetes in colon than lean Ossabaw minipigs (P<0.01). Obese Ossabaws had significantly lower abundances of the genera Prevotella and Lactobacillus and higher abundance of Clostridium in their colon than the lean Ossabaws. Overall, the Göttingen and Ossabaw minipigs displayed different microbial communities in response to diet-induced obesity in the different sections of their intestine.Obesity-related changes in the composition of the gut microbiota were found in lean versus obese Göttingen and Ossabaw minipigs. In both pig models diet seems to be the defining factor that shapes the gut microbiota as observed by changes in different bacteria divisions between lean and obese minipigs