Total Energy Expenditure and Functional Status in Older Adults: A Doubly Labelled Water Study.

OBJECTIVES: Higher total energy expenditure in free living conditions, regardless of any activity, has been strongly associated with a lower risk of mortality in healthy older adults. Also, a good performance in physical and functional tests is a marker of good functional prognosis. However, it is not yet clear what is the association between total energy expenditure and the performance in physical and functional tests. The objective of this study was to verify the association between the total energy expenditure of older adults measured by doubly labelled water and the performance in functional tests. DESIGN: Cross-sectional study. SETTINGS AND PARTICIPANTS: Fifty-six older people were recruited from health services linked to the participating institutions. MEASUREMENTS: Socio-demographic, anthropometric and clinical characteristics were assessed through the application of a structured questionnaire. Body composition was evaluated by isotopic dilution of deuterium oxide and functional status was assessed by the gait speed test, 6-minute walk test and handgrip strength. Total energy expenditure (GET) was assessed using the doubly labelled water method and the physical activity profile was verified using an activity monitor based on accelerometery. RESULTS: The results showed that the highest total energy expenditure correlated with the best performance in the gait speed tests (r = 0.266; p = 0.047), 6-minute walk test (r = 0.424; p = 0.001) and maximum handgrip strength (r = 0.478; p = 0.000). Multivariate regression analysis in a model adjusted for sex and fat-free mass revealed an association between total energy expenditure and the 6-minute walk test (ß = 1.790; t = 2.080; p = 0.044) and the number of sedentary events ( ß = 6.389; t = 2.147; p = 0.038). CONCLUSION: The results of this study suggest that, in clinical practice, older individuals with lower gait speed, worse performance in the 6-minute walk test and lower handgrip strength, may have lower total energy expenditure, being the stimulus for its increase important for the prevention of possible problems related to low energy expenditure.

Optimization of silver-containing bioglass nanoparticles envisaging biomedical applications.

Bioglass nanoparticles (BGs) are of outmost importance in the biomedical field, because their unique characteristics, namely osteoconductivity and osteoinductivity, and also in certain conditions, angiogenic and bactericidal properties. In this work, novel bioglass nanoparticles containing silver (AgBGs) were synthesized by a sol-gel method, adopting different thermal treatments to obtain new nanoparticles with bioactive and antibacterial features. This is the first systematic study of the effect of the thermal treatment on the properties of AgBGs. The effect of the studied thermal treatments on the properties of synthesized nanoparticles was analyzed by several characterization techniques: FT-IR, XRD, S-TEM, SEM-EDS and Zeta potential. FT-IR allowed the identification of the characteristic peaks of the nanoparticles and XRD revealed the presence of the characteristic peaks of an apatite-like phase. By S-TEM analysis it was found that the produced nanoparticles are dense and have a diameter <200 nm. The SEM micrographs showed their surface morphology and Zeta potential measurements were performed to study their suspension stability. Additionally, in vitro bioactivity tests confirmed their bioactive potential and the microbiological tests evidenced their bactericidal effect. These promising AgBGs could be incorporated either in 2D or 3D structures for several biomedical applications, namely in the orthopedic and dental fields.

Chitosan derivatives obtained by chemical modifications for biomedical and environmental applications.

Chitosan is a natural based polymer, obtained by alkaline deacetylation of chitin, which presents excellent biological properties such as biodegradability and immunological, antibacterial and wound-healing activity. Recently, there has been a growing interest in the chemical modification of chitosan in order to improve its solubility and widen its applications. The main chemical modifications of chitosan that have been proposed in the literature are reviewed in this paper. Moreover, these chemical modifications lead to a wide range of derivatives with a broad range of applications. Recent and relevant examples of the distinct applications, with particular emphasis on tissue engineering, drug delivery and environmental applications, are presented.

Microhardness of starch based biomaterials in simulated physiological conditions.

In this work the variation of the surface mechanical properties of starch-based biomaterials with immersion time was followed using microhardness measurements. Two blends with very distinct water uptake capabilities, starch/cellulose acetate (SCA) and starch/poly(epsilon-caprolactone) (SPCL), were immersed in a phosphate buffer solution (PBS) at 37.5 degrees C for various times. The microhardness of the blends decreased significantly ( approximately 50% for SPCL and approximately 94% for SCA), within a time period of 30 days of immersion, reflecting the different hydrophilic character of the synthetic components of the blends. The dependence of microhardness on the applied loading time and load was also analysed and showed a power law dependency for SCA. Water uptake and weight loss measurements were performed for the same immersion times used in the microhardness experiments. The different swelling/degradation behaviour presented by the blends was related to the respective variation in microhardness. Moreover, complementary characterization of the mechanical properties of SCA and SPCL was accomplished by dynamic mechanical analysis (DMA) and creep measurements. Microhardness measurements proved to be a useful technique for characterizing the mechanical behaviour near the surface of polymeric biomaterials, including in simulated physiological conditions.

Body Mass Index and Its Relationship with Disability, Chronic Diseases and Frailty in Older People: A Comparison of the Lipschitz and Who Classifications.

BACKGROUND: Anthropometric parameters are closely associated with the pathophysiology of frailty and with clinic and functional parameters assessed for its diagnosis. OBJECTIVE: To evaluate the possible association of the nutritional status of older people as assessed by Body Mass Index (BMI) and functional disability, self-reported chronic diseases and frailty, comparing the use of two different classifications of BMI. DESIGN: Cross-sectional study. SETTING: The sample was selected among community-dwelling older people from the city of Ribeirão Preto/ Brazil. PARTICIPANTS: 326 independent older people (mean age 73.8±6.4 years) who participated in the FIBRA (Frailty in Brazilian Older People) study. MEASUREMENTS: Weight and height were collected for BMI analysis and frailty criteria were applied according to Fried et al. Participants were also evaluated for self-reported activities of daily living (Katz Index and Lawton and Brody Scale), and the presence of chronic diseases. RESULTS: The prevalence of frailty was 12.3%. Regardless of the classification of BMI applied, most of the sample was classified as overweight (50.9% and 39.3% in the Lipschitz and WHO classifications, respectively). For both classifications, low weight was the only BMI classification associated with frailty status (OR Lipschitz: 4.12(1.53-11.14); OR WHO: 6.21 (1.26-30.58). Comorbidities and dependence in activities of daily living (ADLs) were associated with BMI ≥ 30kg.m2. CONCLUSION: Regardless of the classification adopted, low weight is associated with frailty. However, when the WHO stratification is employed, high BMI is also associated to increased functional disability and the presence of comorbidities, coexisting factors of frailty.

Antibacterial bioadhesive layer-by-layer coatings for orthopedic applications.

In this study, thin LbL films were produced by combining the adhesive properties of the hyaluronic acid-dopamine conjugate with the bioactivity and bactericidal properties of silver doped bioactive glass nanoparticles. The build-up of these films was investigated by quartz crystal microbalance with dissipation monitoring. LbL coatings were then constructed on a glass substrate for further characterization. We found that these antimicrobial bioinspired films display enhanced adhesive strength. In vitro bioactivity tests were performed by immersing them in simulated body fluid solution for 14 days where the constructed films promoted the formation of a bone-like apatite layer. From microbiological assays, it was found that coatings containing silver doped nanoparticles exhibited a remarkable antibacterial effect against Staphylococcus aureus and Escherichia coli cultures. Finally, in vitro cellular behavior tests showed enhanced cell adhesion, proliferation and viability for these antibacterial bioadhesive films. Therefore, the constructed thin films showed promising properties and evidenced great potential to be used as coatings for orthopedic implants.

High performance free-standing films by layer-by-layer assembly of graphene flakes and ribbons with natural polymers.

In this work, novel free-standing (FS) films based on chitosan, alginate and graphene oxide (GO) were developed through layer-by-layer assembly. First, GO was synthesized from graphite and multi-walled carbon nanotubes using a modified Hummer's method, yielding oxidized graphene flakes (o-GFs) and oxidized graphene nanoribbons (o-GNRs), respectively, which were then characterized. Then FS films were produced and their morphological, thermal and mechanical properties, as well as the o-GF and o-GNR dispersion along the films were assessed. Their degradation and swelling profiles as well as their biological behavior were evaluated. Graphite and nanotubes were successfully oxidized and exfoliated forming stable suspensions that could be combined with chitosan (CHI) and alginate (ALG) solutions by layer-by-layer processing. The addition of o-GFs and o-GNRs resulted in rougher, hydrophilic FS films with significantly improved mechanical properties relative to CHI/ALG films. The presence of o-GFs or o-GNRs did not affect the thermal stability and the addition of o-GFs resulted in films with enhanced cytocompatibility. The results demonstrate the high potential of the GO reinforced films for biomedical applications, in particular o-GF films, for wound healing, and cardiac and bone engineering applications.

Confinement effects on the dynamic behavior of poly(D,L-lactic acid) upon incorporation in α-cyclodextrin.

Inclusion complexes (ICs) composed of α-cyclodextrin (α-CD) and poly(D,L-lactic acid) (PDLLA), with 10/24 (IC1) and 15/46 (IC2) (% w/w) of PDLLA incorporated/initial PDLLA weight percentage, were prepared and characterized mainly by dielectric relaxation spectroscopy (DRS). Bulk PDLLA was also analyzed for comparison. DRS was revealed to be a suitable tool to distinguish the dynamical response of the PDLLA regions constrained in between α-CD channels from the fraction incorporated inside channels. While the cooperative α-process undergoes a dramatic depletion shifting to higher temperatures (∼4.5 °C) for the PDLLA interchannels portion, it is suppressed for PDLLA chains inside pores. It was demonstrated that the broad secondary relaxation of bulk PDLLA is the Johari-Goldstein process (ßJG-process). The detection of its analogue in the ICs at higher frequencies, to a greater extent in IC1, is interpreted as a true confinement effect where the dimensions of the α-CD channels interfere with the length scale of the ßJG-process. The limit predicted in the framework of the coupling model, where the α-relaxation transforms in the ßJG-process, seems to be reached in the ICs. Furthermore, it was found that the length scale of the additional γ process only detected in the ICs is inferior to inter- or intrachannel dimensions.

Lâminas de irrigação e sombreamento na produção de biomassa de Acariçoba (Hydrocotyle umbellata L. ) / Levels of irrigation and shade in the production of the biomass of dollarweed (Hydrocotyle umbellata L. )

RESUMO: A acariçoba é uma planta utilizada pela medicina ayurvédica e em cosméticos por possuir propriedades rejuvenescedoras e revitalizante do sistema nervoso e cérebro. Com objetivo de avaliar os caracteres agronômicos e o teor de flavonóides totais de acariçoba em resposta a aplicação de lâminas distintas de irrigação e sombreamento, foi conduzido um experimento em área localizada nas coordenadas 17º 47' 53'' latitude (S); longitude (W) - 51º 55' 53'', com altitude média de 648m, no período de julho a novembro. O clima é Aw (tropical), relevo suave ondulado (8% de declividade) com solo classificado como Latossolo Vermelho Distroférrico e textura argilosa. As temperaturas médias anuais são 18,1ºC e 30ºC. A umidade relativa do ar média é de 64,7% e a precipitação total anual média é de 1550 mm, com estações do ano seca e chuvosa, bem definidas. O ensaio foi conduzido em blocos casualizados em esquema fatorial 2 x 2, com 5 repetições totalizando vinte unidades experimentais com dois manejos de irrigação, sendo um com aplicação de uma lâmina de água diariamente, e outro, com duas aplicações de lâmina de água diariamente. Os tratamentos de sombreamento foram a pleno sol e com 50% de sombreamento. Foram avaliadas a massa fresca e massa seca das partes aéreas, a altura e o número de plantas, e o teor de flavonóides totais das partes aéreas. A produção de flavonóides foi favorecida pelo sombreamento, enquanto a irrigação não influenciou nem na produção de flavonoides, nem nos caracteres agronômicos avaliados.

ABSTRACT: Dollarweed is a plant that is widely used by the Ayurvedic medicine and in the cosmetics industry because of its rejuvenating and revitalizing properties related to the nervous system and the brain. In order to evaluate the agronomic characteristics and the content of total flavonoids of the dollarweed, in response to the application of different levels of irrigation and shade, an experiment was conducted in an area at the coordinates 17º 47' 53'' latitude (S), 51º 55' 53'' longitude (W), with a mean altitude of 648m, from July to November. The climate is Aw (tropical), gently undulating relief (8% slope) with distroferric red latosol and clayey texture. The average annual temperatures are 18.1 ºC and 30 ºC. The average relative humidity of the air is 64.7% and the average annual rainfall is 1550 mm, with well-defined dry and rainy seasons. The assay was in randomized blocks, with a 2 x 2 factorial design, with 5 repetitions, amounting to twenty experimental units with two irrigation managements, being one with a daily application of water and the other with two daily applications of water. The shading treatments were under full sun and 50% shade. The fresh and dry weights of the aerial parts, the height and number of plants and the total content of flavonoids of the aerial parts were evaluated. The production of flavonoids was favored by the shade; irrigation did not influence the production of flavonoids or the agronomic characters evaluated.