This review covers the preparation, characterization, properties, and applications of methylcelluloses (MC). In particular, the influence of different chemical modifications of cellulose (under both ...heterogeneous and homogeneous conditions) is discussed in relation to the physical properties (solubility, gelation) of the methylcelluloses. The molecular weight (MW) obtained from the viscosity is presented together with the nuclear magnetic resonance (NMR) analysis required for the determination of the degree of methylation. The influence of the molecular weight on the main physical properties of methylcellulose in aqueous solution is analyzed. The interfacial properties are examined together with thermogelation. The surface tension and adsorption at interfaces are described: surface tension in aqueous solution is independent of molecular weight but the adsorption at the solid interface depends on the MW, the higher the MW the thicker the polymeric layer adsorbed. The two-step mechanism of gelation is confirmed and it is shown that the elastic moduli of high temperature gels are not dependent on the molecular weight but only on polymer concentration. Finally, the main applications of MC are listed showing the broad range of applications of these water soluble cellulose derivatives.
OBJECTIVES: The aim of the present study was to examine the prevalence and factors associated with sarcopenia in older residents in São Paulo, Brazil. DESIGN: Cross-sectional study. SETTING: São ...Paulo, Brazil. PARTICIPANTS: 1,149 older individuals from the second wave of the Saúde, Bem-Estar e Envelhecimento (SABE) study from 2006. MEASUREMENTS: The definition of sarcopenia was based on the consensus of the European Working Group on Sarcopenia in Older People (EWGSOP), which include three components: low muscle mass, assessed by a skeletal muscle mass index of ≤8.90kg/m² for men and ≤6.37kg/m² for women; low muscle strength, assessed by handgrip strength <30kg for men and <20kg for women; and low physical performance, assessed by gait speed <0.8m/s. Diagnosis of sarcopenia required presence of low muscle mass plus low muscle strength or low physical performance. Socio-demographic and behavioral characteristics, medical conditions and nutritional status were considered as independent variables to determine the associated factors using a logistic regression model. RESULTS: The prevalence of sarcopenia was 16.1% in women and 14.4% in men. Advanced age with a dose response effect, cognitive impairment, lower income, smoking, undernutrition and risk for undernutrition (p<0.05) were factors associated with sarcopenia. CONCLUSIONS: The EWGSOP algorithm is useful to define sarcopenia. The prevalence of sarcopenia in the Brazilian elderly population is high and several associated factors show that this syndrome is affected by multiple domains. No differences were observed by gender in any age groups.
•NIRS was applied to predict total anthocyanins content (TAC) and total phenolic compounds (TPC) in wax jambu fruit.•The PLS analysis for quantitative prediction of both parameters gave excellent ...accuracy values.•For TAC, PLS model produced prediction accuracy (rp=0.98, RMSECV=7.56mgL−1, RMSEP=9.0mgL−1 and RPD=5.19).•For TPC, PLS model produced prediction accuracy (rp=0.94, RMSECV=19.01mgL−1, RMSEP=22.18mgL−1 and RPD=3.27).
The aim of this work was to develop an analytical method to predict total anthocyanins content (TAC) and total phenolic compounds (TPC) in intact wax jambu fruit Syzygium malaccense (L.) Merryl et Perry using near-infrared spectroscopy (NIRS) and partial least squares (PLS). The estimation accuracy was based on parameters such as root mean square error of prediction (RMSEP), correlation coefficients calibration (rc) and prediction (rp) set and ratio of performance to deviation (RPD). TAC, rp=0.98, RMSEP=9.0mgL−1 and RPD=5.19 were attained using second derivative pre-treatment. TPC, rp=0.94, RMSEP=22.18 (mg gallic acid equivalents (GAE)/100g) and RPD=3.27 (excellent accuracy) were also obtained using second derivative pre-treatment. These findings suggest that the NIRS and PLS algorithms can be used to determine TCA and TPC in intact wax jambu fruit.
BACKGROUND: Sarcopenia and dynapenia have been associated with poorer physical performance, disability and death. The aim of this study was to compare the association between sarcopenia and dynapenia ...with mortality. METHODS: We studied 1,149 Brazilians aged 60 years or older residing in São Paulo. Sarcopenia was defined according to the consensus of the European Working Group on Sarcopenia in Older People (EWGSOP), which includes three components: low muscle mass (LMM) assessed by skeletal muscle mass index ≤ 8.90kg/m2 (men) and ≤ 6.37kg/m2 (women); low muscle strength (LMS) assessed by handgrip strength < 30kg (men) and < 20kg (women); and low physical performance (LPP) assessed by walking speed ≤ 0.8m/s. Diagnosis of sarcopenia required presence of LMM plus LMS or LPP. Dynapenia was defined as handgrip strength < 30kg (men) and < 20kg (women). Covariates included socio-demo graphic and behavioral variables, medical conditions, hospitalization, depressive symptoms, cognition, and disability in activities of daily living or instrumental activities of daily living. The outcome was all-cause mortality over five-year follow-up. RESULTS: During the five-year follow-up, 187 subjects died. The mortality rate for those with or without sarcopenia were 65.9/1,000 person/years and 20.1/1,000 person/years and for dynapenia were 44.3/1,000 person/years and 14.9/1,000 person/years. The adjusted model showed that sarcopenia (HR=1.52, 95%CI: 1.06–2.19) and dynapenia (HR=2.04, 95%CI: 1.24–3.37) are independent risk factors for death. CONCLUSIONS: The EWGSOP definition of sarcopenia and dynapenia can help to determine risk for mortality and can be used as a screening instrument in public health.
Individual variability in word generation is a product of genetic and environmental influences. The genetic effects on semantic verbal fluency were estimated in 1,735 participants from the Brazilian ...Baependi Heart Study. The numbers of exemplars produced in 60 s were broken down into time quartiles because of the involvement of different cognitive processes-predominantly automatic at the beginning, controlled/executive at the end. Heritability in the unadjusted model for the 60-s measure was 0.32. The best-fit model contained age, sex, years of schooling, and time of day as covariates, giving a heritability of 0.21. Schooling had the highest moderating effect. The highest heritability (0.17) was observed in the first quartile, decreasing to 0.09, 0.12, and 0.0003 in the following ones. Heritability for average production starting point (intercept) was 0.18, indicating genetic influences for automatic cognitive processes. Production decay (slope), indicative of controlled processes, was not significant. The genetic influence on different quartiles of the semantic verbal fluency test could potentially be exploited in clinical practice and genome-wide association studies.
The biological pump transports organic carbon produced by photosynthesis to the meso- and bathypelagic zones, the latter removing carbon from exchanging with the atmosphere over centennial time ...scales. Organisms living in both zones are supported by a passive flux of particles, and carbon transported to the deep-sea through vertical zooplankton migrations. Here we report globally-coherent positive relationships between zooplankton biomass in the epi-, meso-, and bathypelagic layers and average net primary production (NPP). We do so based on a global assessment of available deep-sea zooplankton biomass data and large-scale estimates of average NPP. The relationships obtained imply that increased NPP leads to enhanced transference of organic carbon to the deep ocean. Estimated remineralization from respiration rates by deep-sea zooplankton requires a minimum supply of 0.44 Pg C y
transported into the bathypelagic ocean, comparable to the passive carbon sequestration. We suggest that the global coupling between NPP and bathypelagic zooplankton biomass must be also supported by an active transport mechanism associated to vertical zooplankton migration.
► Aloe extract (AE) and polysaccharidic fraction (PF) of Aloe leaves pulp were studied. ► PF is mainly constituted by a partially acetylated 4-linked β-d-glucomannan. ► Acetyl groups are located at ...C-2, C-2 and C-3, C-3 and/or C-6 of Manp units. ► AE is composed by a high amount of free glucose (61%) and the acetylated glucomannan. ► AE and PF showed pseudoplastic behavior and PF higher viscoelastic properties.
The structural and rheological properties of the Aloe extract (AE) and the polysaccharidic fraction (PF) obtained from the leaves pulp of Aloe barbadensis Miller were investigated. Structural analyses carried out by composition, methylation analysis and NMR spectroscopy showed that PF is mainly constituted by a partially acetylated 4-linked β-d-glucomannan. The acetyl groups are located at C-2, C-2 and C-3, C-3 and/or C-6. The acetylation pattern of this type of polysaccharide was for the first time established using bidimensional NMR analyses. AE and PF aqueous solutions at 25°C showed a non-Newtonian behavior (with pseudoplastic characteristics), however PF showed higher apparent viscosity than AE. Dynamic oscillatory analyses showed that both samples, at the same concentration, behaved as a concentrated solution. PF presented higher values of G′ compared with those of AE and this behavior could be consequence of its higher content in partially acetylated glucomannan.
A new class of highly fluorescent, photostable, and magnetic core/shell nanoparticles in the submicrometer size range has been synthesized from a modified Stöber method combined with the ...layer‐by‐layer (LbL) assembly technique. Luminescent magnetic nanoparticles are prepared via two main steps. The first step involves controlled addition of tetraethoxysilane to a dispersion of Fe3O4/γ‐Fe2O3 nanoparticles, which are thereby homogeneously incorporated as cores into monodisperse silica spheres. The second step involves the LbL assembly of polyelectrolytes and luminescent CdTe quantum dots onto the surfaces of the silica‐coated magnetite/maghemite particles, which are finally covered with an outer shell of silica. These spherical particles have a typical diameter of 220 ± 10 nm and a saturation magnetization of 1.34 emu g–1 at room temperature, and exhibit strong excitonic photoluminescence. Nanoparticles with such a core/shell architecture have the added benefit of providing a robust platform (the outer silica shell) for incorporating diverse functionalities into a single nanoparticle.
Water‐based luminescent magnetic colloidal particles have been prepared by the encapsulation of iron oxide nanoparticles and luminescent semiconductor nanocrystals in silica spheres. These patterned magnetic silica spheres are expected to serve as luminescent markers while attached to bioligands, and are capable of being driven by a magnetic field (see Figure and cover).
Paraquat dichloride (methyl viologen; PQ) is an effective and widely used herbicide that has a proven safety record when appropriately applied to eliminate weeds. However, over the last decades, ...there have been numerous fatalities, mainly caused by accidental or voluntary ingestion. PQ poisoning is an extremely frustrating condition to manage clinically, due to the elevated morbidity and mortality observed so far and due to the lack of effective treatments to be used in humans. PQ mainly accumulates in the lung (pulmonary concentrations can be 6 to 10 times higher than those in the plasma), where it is retained even when blood levels start to decrease. The pulmonary effects can be explained by the participation of the polyamine transport system abundantly expressed in the membrane of alveolar cells type I, II, and Clara cells. Further downstream at the toxicodynamic level, the main molecular mechanism of PQ toxicity is based on redox cycling and intracellular oxidative stress generation. With this review we aimed to collect and describe the most pertinent and significant findings published in established scientific publications since the discovery of PQ, focusing on the most recent developments related to PQ lung toxicity and their relevance to the treatment of human poisonings. Considerable space is also dedicated to techniques for prognosis prediction, since these could allow development of rigorous clinical protocols that may produce comparable data for the evaluation of proposed therapies.
Purpose Discrepancies between subjective and objective measures of total sleep time (TST) are frequent among insomnia patients, but this issue remains scarcely investigated in obstructive sleep apnea ...(OSA). We aimed to evaluate if sleep perception is affected by the severity of OSA. Methods We performed a 3-month cross-sectional study of Brazilian adults undergoing overnight polysomnography (PSG). TST was objectively assessed from PSG and by a self-reported questionnaire (subjective measurement). Sleep perception index (SPI) was defined by the ratio of subjective and objective values. Diagnosis of OSA was based on an apnea/hypopnea index (AHI) greater than or equal to 5.0/h, being its severity classified according to AHI thresholds: 5.0-14.9/h (mild OSA), 15.0-29.9/h (moderate OSA), and greater than or equal to 30.0/h (severe OSA). Results Overall, 727 patients were included (58.0% males). A significant difference was found in SPI between non-OSA and OSA groups (p = 0.014). Mean SPI values significantly decreased as the OSA severity increased: without OSA (100.1 #177; 40.9%), mild OSA (95.1 #177; 24.6%), moderate OSA (93.5 #177; 25.2%), and severe OSA (90.6 #177; 28.2%), p = 0.036. Using logistic regression, increasing SPI was associated with a reduction in the likelihood of presenting any OSA (p = 0.018), moderate/severe OSA (p = 0.019), and severe OSA (p = 0.028). However, insomnia was not considered as an independent variable for the presence of any OSA, moderate/severe OSA, and severe OSA (all p-values > 0.05). Conclusion In a clinical referral cohort, SPI significantly decreases with increasing OSA severity, but is not modified by the presence of insomnia symptoms.
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