Pyrolyzed chitosan-based materials for CO2/CH4 separation

Chitosan is a biopolymer obtained by deacetylation of chitin extracted from sub-products of the food industry and it is rich in nitrogen content. Pyrolyzed chitosan– and chitosan-periodic mesoporous organosilica (PMO)– based porous materials with different pore structures and chemical features are prepared using different dry methods and ensuing pyrolysis at 800 °C, for application in the CO2/CH4 adsorption/separation. The highest CO2 adsorption capacity (1.37 mol·kg−1 at 100 kPa; 1.9 mol·kg−1 at 500 kPa) and the best selectivity for CO2/CH4 separation (95 at 500 kPa) is obtained using 1.5% (m/v) of chitosan solution dried under supercritical CO2. This material combines a good CO2 adsorption capacity with one of the highest selectivities for CO2/CH4 separation of the literature, arising as a promising alternative adsorbent for natural gas or biogas upgrading at reduced cost. The presence of high nitrogen content together with pores of diameter around 2 nm leads to an increase of the CO2 adsorption capacity. In the case of chitosan-PMO-based materials, the activation step using both acid and crushing methods is crucial to increase the CO2 adsorbed amount. Here, the highest CO2 adsorption capacity and the highest selectivity are obtained by the chitosan-PMO crushed adsorbent and the chitosan-PMO material activated with sulfuric acid, respectively. These observations indicate the importance of the controlled attack of the material surface to enhance the diffusion of the target gases within the adsorbent, avoiding the adsorption of other species.publishe

Towards a natural classification : the taxonomy and evolution of Xanthorrhoea

The ability to increase the filler content of paper without significantly sacrificing its mechanical strength is of high interest for papermakers. In this work, three samples of ground calcium carbonate (GCC), differing in size and in brightness, modified with silica via the sol-gel method, were used as fillers in papermaking. Handsheets were produced using a eucalyptus kraft pulp furnish and with a filler amount near 20%. It was found that not only were the strength properties of the handsheets produced with the modified GCCs always significantly better than those obtained with the unmodified GCCs (e.g., the tensile index exhibited improvements of 16 to 20%), but bulk also was increased (by 7 to 13%). Some decreases in the light scattering and opacity values were noted when using the modified GCC, but the brightness was roughly the same. The enhanced fiber-to-filler bonding may be attributed to the hydrogen bonding between the cellulosic fibers and the hydroxyl groups of the silica coating the calcium carbonate particles

Importância dos Dispositivos Eletrónicos Cardíacos Implantáveis no Diagnóstico da Síndrome da Apneia do Sono

Introduction: Sleep Apnea Syndrome (SAS) is a prevalent respiratory disease with marked expression in the population with cardiovascular disease. The diagnosis is based on polysomnography. In patients with cardiac implantable electronic devices (CIED), the prevalence of SAS may reach 60%. The objective of this study was to evaluate the value of DEC in the SAS screening. Methods: Prospective study that included patients with CIED with sleep apnea algorithm. The frequency response function was activated and simplified polygraphy was performed. The data of the device were collected on the day of the polygraph. Results: The sample included 29 patients, with a mean age of 76.1 years, 71.4% of the male gender. The prevalence of SAS was 77%. For SAS, the agreement between polysomnography and the Pacemaker was Kappa = 0.54 (p = 0.001), 95% CI (0.28, 0.81) (moderate agreement); for moderate to severe SAS, the agreement was Kappa = 0.73 (p <0.001), 95% CI (0.49, 0.976) (substantial agreement). Severe SAS was obtained: sensitivity 60%, specificity 100%, positive predictive value 100%, negative predictive value 60% and diagnostic accuracy 75%; for moderate to severe SAS: sensitivity of 90%, specificity of 83%, positive predictive values of 90% and negative of 87.5%, with a diagnostic accuracy of 87.5%. Conclusion: SAS is highly prevalent in patients with CIED. The values obtained through these devices have a strong positive correlation with the Apnea-Hypopnea Índex, which makes them a good tool for the screening of severe SAS.info:eu-repo/semantics/publishedVersio

Low frequency of CD4(+) CD25(+) Treg in SLE patients: a heritable trait associated with CTLA4 and TGF gene variants

Background: CD4(+)CD25(+) regulatory T cells play an essential role in maintaining immune homeostasis and preventing autoimmunity. Therefore, defects in Treg development, maintenance or function have been associated with several human autoimmune diseases including Systemic Lupus Erythematosus (SLE), a systemic autoimmune disease characterized by loss of tolerance to nuclear components and significantly more frequent in females

Benzyl N-((S)-2-hydr­oxy-1-{N′-[(E)-2-methoxy­benzyl­idene]hydrazinecarbon­yl}eth­yl)carbamate from synchrotron data

A U-shaped conformation is found in the title compound, C19H21N3O5, with the benzene rings lying to the same side of the mol­ecule; the dihedral angle between them is 10.83 (16)°. The dihedral angle formed between the hydrazinecarbonyl and carbamate residues is 68.42 (13)°. The carbonyl groups lie approximately at right angles to each other [O—C⋯C—O pseudo torsion angle of 107.7 (3)°], and the conformation about the C12=N3 bond [1.279 (4) Å] is E. An intra­molecular Ncb—H⋯Ohy (cb = carbmate and hy = hydr­oxy) hydrogen bond occurs, generating an S(6) loop. In the crystal, inter­molecular Oh—H⋯Oca (ca = carbon­yl) and Nhz—H⋯Oca (hz = hydrazine) hydrogen bonds lead to the formation of a supra­molecular chain, two mol­ecules thick, which propagates along the a axis; these are connected by C—H⋯Oca contacts

How gamma-rays and electron-beam irradiation would affect the antimicrobial activity of differently processed wild mushroom extracts?

Aims: The effects of irradiation (gamma-rays and electron-beams), up to 10 kGy, in the antimicrobial activity of mushroom species (Boletus edulis, Hydnum repandum, Macrolepiota procera and Russula delica) differently processed (fresh, dried, freeze) were evaluated. Methods and Results: Clinical isolates with different resistance profiles from hospitalized patients in Local Health Unit of Mirandela, Northeast of Portugal, were used as target micro-organisms. The mushrooms antimicrobial activity did not suffer significant changes that might compromise applying irradiation as a possible mushroom conservation technology. Conclusions: Two kGy dose (independently of using gamma-rays or electron-beams) seemed to be the most suitable choice to irradiate mushrooms. Significance and Impact of the Study: This study provides important results in antimicrobial activity of extracts prepared from irradiated mushroom species.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and COMPETE/QREN/EU for financial support to CIMO (PEst-OE/AGR/UI0690/2011), Â. Fernandes (SFRH/BD/76019/2011) and J.C.M. Barreira (SFRH/BPD/72802/2010). They also thank to the Local Health Unit of Mirandela, Northeast of Portugal, for all the support and to INCT - Institute of Nuclear Chemistry and Technology, in Warsaw, Poland for electron-beam irradiation

Association of the fibronectin type III domain–containing protein 5 rs1746661 single nucleotide polymorphism with reduced brain glucose metabolism in elderly humans

Fibronectin type III domain–containing protein 5 (FNDC5) and its derived hormone, irisin, have been associated with metabolic control in humans, with described FNDC5 single nucleotide polymorphisms being linked to obesity and metabolic syndrome. Decreased brain FNDC5/irisin has been reported in subjects with dementia due to Alzheimer’s disease. Since impaired brain glucose metabolism develops in ageing and is prominent in Alzheimer’s disease, here, we examined associations of a single nucleotide polymorphism in the FNDC5 gene (rs1746661) with brain glucose metabolism and amyloid-β deposition in a cohort of 240 cognitively unimpaired and 485 cognitively impaired elderly individuals from the Alzheimer’s Disease Neuroimaging Initiative. In cognitively unimpaired elderly individuals harbouring the FNDC5 rs1746661(T) allele, we observed a regional reduction in low glucose metabolism in memory-linked brain regions and increased brain amyloid-β PET load. No differences in cognition or levels of cerebrospinal fluid amyloid-β42, phosphorylated tau and total tau were observed between FNDC5 rs1746661(T) allele carriers and non-carriers. Our results indicate that a genetic variant of FNDC5 is associated with low brain glucose metabolism in elderly individuals and suggest that FNDC5 may participate in the regulation of brain metabolism in brain regions vulnerable to Alzheimer’s disease pathophysiology. Understanding the associations between genetic variants in metabolism-linked genes and metabolic brain signatures may contribute to elucidating genetic modulators of brain metabolism in humans