Estudio del óxido de grafeno (GO) en la densificación de β-fosfato tricálcico

Se obtuvo un biocerámico a partir de los reactivos analíticos del GO y β-Ca3(PO4)2, este último con contenidos mínimos de Hap y P2O7, los cuales fueron homogeneizados por micromolienda, con el fin de aumentar el área de contacto y las posibilidades del mecanismo de densificación. El estudio de funcionalización del biocerámico, GO/β-Ca3(PO4)2, se realizó a temperaturas de 500 hasta 800°C por 1 y 2 h, bajo atmósfera controlada de argón. La sinterización se observó por la reducción de las partículas debido al crecimiento, engrosamiento y unión entre los granos; lo cual sugirió que se reduce la energía total del biocerámico y lo compacta a medida que aumenta la temperatura, así como, la concentración del GO desde 0.015 a 0.075%. Los resultados del análisis por espectroscopía de absorción infrarroja mostraron la desaparición gradual de los grupos funcionales de la Hap en función de la temperatura.A bioceramic was obtained from GO and β-Ca3(PO4)2 analytical reagents, the latest with minimal content of Hap and P2O7, which were homogenized by micro-grinding, in order to increase the contact area and the possibilities of the densification mechanism. The bioceramic functionalization study, GO/β-Ca3(PO4)2, it was performed at temperatures of 500 to 800°C for 1 and 2 h, under a controlled argon atmosphere. Sintering was observed by the reduction of the particles due to the growth, thickening and union between the grains; which suggested that the total energy of the bioceramic is reduced and compacted as the temperature increases, as well as, the concentration of GO from 0.015 to 0.075%. The results of the analysis by infrared absorption spectroscopy showed the gradual disappearance of the functional groups of the Hap as a function of temperature

Common and rare variant association analyses in amyotrophic lateral sclerosis identify 15 risk loci with distinct genetic architectures and neuron-specific biology

A cross-ancestry genome-wide association meta-analysis of amyotrophic lateral sclerosis (ALS) including 29,612 patients with ALS and 122,656 controls identifies 15 risk loci with distinct genetic architectures and neuron-specific biology. Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a lifetime risk of one in 350 people and an unmet need for disease-modifying therapies. We conducted a cross-ancestry genome-wide association study (GWAS) including 29,612 patients with ALS and 122,656 controls, which identified 15 risk loci. When combined with 8,953 individuals with whole-genome sequencing (6,538 patients, 2,415 controls) and a large cortex-derived expression quantitative trait locus (eQTL) dataset (MetaBrain), analyses revealed locus-specific genetic architectures in which we prioritized genes either through rare variants, short tandem repeats or regulatory effects. ALS-associated risk loci were shared with multiple traits within the neurodegenerative spectrum but with distinct enrichment patterns across brain regions and cell types. Of the environmental and lifestyle risk factors obtained from the literature, Mendelian randomization analyses indicated a causal role for high cholesterol levels. The combination of all ALS-associated signals reveals a role for perturbations in vesicle-mediated transport and autophagy and provides evidence for cell-autonomous disease initiation in glutamatergic neurons

The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar and APOGEE-2 Data

This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library (MaStar) accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) survey which publicly releases infra-red spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the sub-survey Time Domain Spectroscopic Survey (TDSS) data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey (SPIDERS) sub-survey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated Value Added Catalogs (VACs). This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper (MWM), Local Volume Mapper (LVM) and Black Hole Mapper (BHM) surveys

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Canagliflozin and Cardiovascular and Renal Outcomes in Type 2 Diabetes Mellitus and Chronic Kidney Disease in Primary and Secondary Cardiovascular Prevention Groups

Background: Canagliflozin reduces the risk of kidney failure in patients with type 2 diabetes mellitus and chronic kidney disease, but effects on specific cardiovascular outcomes are uncertain, as are effects in people without previous cardiovascular disease (primary prevention). Methods: In CREDENCE (Canagliflozin and Renal Events in Diabetes With Established Nephropathy Clinical Evaluation), 4401 participants with type 2 diabetes mellitus and chronic kidney disease were randomly assigned to canagliflozin or placebo on a background of optimized standard of care. Results: Primary prevention participants (n=2181, 49.6%) were younger (61 versus 65 years), were more often female (37% versus 31%), and had shorter duration of diabetes mellitus (15 years versus 16 years) compared with secondary prevention participants (n=2220, 50.4%). Canagliflozin reduced the risk of major cardiovascular events overall (hazard ratio [HR], 0.80 [95% CI, 0.67-0.95]; P=0.01), with consistent reductions in both the primary (HR, 0.68 [95% CI, 0.49-0.94]) and secondary (HR, 0.85 [95% CI, 0.69-1.06]) prevention groups (P for interaction=0.25). Effects were also similar for the components of the composite including cardiovascular death (HR, 0.78 [95% CI, 0.61-1.00]), nonfatal myocardial infarction (HR, 0.81 [95% CI, 0.59-1.10]), and nonfatal stroke (HR, 0.80 [95% CI, 0.56-1.15]). The risk of the primary composite renal outcome and the composite of cardiovascular death or hospitalization for heart failure were also consistently reduced in both the primary and secondary prevention groups (P for interaction >0.5 for each outcome). Conclusions: Canagliflozin significantly reduced major cardiovascular events and kidney failure in patients with type 2 diabetes mellitus and chronic kidney disease, including in participants who did not have previous cardiovascular disease

Fabrication of TiO2/ZnO nanofibers for energy storage applications

Se estudiaron nanofibras de TiO2/ZnO preparadas por calcinación de fibras precursoras de poli (vinil acetato), isopropóxido de titanio y nano polvo de zinc elaboradas por la técnica de electrohilado. La estructura y la morfología de las nanofibras de TiO2/ZnO y fibras precursoras se caracterizaron por Microscopia Electrónica de Barrido (SEM), Microscopia Electrónica de Barrido de Emisión de Campo equipado con Espectroscopia Dispersiva de Rayos X (FESEM-EDS), Espectroscopia de Infrarrojo con Transformada de Fourier (FTIR) y Difracción de Rayos X (XRD). El análisis XRD mostró la estructura cristalina de los óxidos de titanio (anatasa) y de zinc (wurzita hexagonal), después de calcinar las fibras precursoras a 500 °C. Las microfotografías de SEM muestran que tanto las fibras precursoras como las nanofibras forman redes uniformes y buena morfología. Estas nanofibras de dióxido de titanio /óxido de zinc presentan buen área de superficie y diámetros de 200 nm apropiados que podrían ser de aplicación potencial en el campo de energía renovable, en particular, para la fabricación de celdas solares.The TiO2 /ZnO nanofibers prepared by the calcination of polyvinyl acetate of precursor fibers, titanium isopropoxide and nano zinc powder produced by the electrospinning technique were studied. The structure and morphology of TiO2 /ZnO nanofibers and precursor fibers were characterized by Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy coupled to Energy Dispersive X-ray spectroscopy (FESEM-EDS), Fourier Transform Infrared Spectroscopy (FTIR) and XRD (X Ray Diffraction). XRD analysis displayed crystalline structures of titanium oxides (anatase) and zinc (hexagonal wurzite), after calcining the precursor fibers at 500 °C. SEM microphotographs display that both precursor fibers and nanofibers form uniform networks and good morphology. These titanium dioxide / zinc oxide nanofibers get good surface area and appropriate 200 nm diameters which could potentially be applied in the renewable energy field, particularly for solar cells manufacturing

Enzymatic ring-opening polymerization of ε-caprolactone by Yarrowia lipolytica lipase in ionic liquids

12 páginas, 17 figuras, 1 esquema, 2 tablas.Yarrowia lipolytica (YLL), Candida rugosa (CRL), and porcine pancreatic lipase (PPL) were employed successfully as catalysts in the enzymatic ring-opening polymerization (ROP) of ε-caprolactone in the presence of 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), 1-butylpyridinium tetrafluoroborate ([BuPy][BF4]), 1-butylpyridinium trifluoroacetate ([BuPy][CF3COO]), 1-ethyl-3-methylimidazolium nitrate ([EMIM][NO3]) ionic liquids. Poly(ε-caprolactone)s (PCLs) with molecular weights (Mn) in the range of 300–9000 Da were obtained. 1H- and 13C-NMR analyses on PCLs formed by YLL, CRL, and PPL showed asymmetric telechelic -hydroxy-ω-carboxylic acid end groups. Differences between CP-MAS and MAS spectra are observed and discussed in terms of morphology. MALDI-TOF spectra show the formation of at least seven species. Differential scanning calorimetry (DSC) and Wide Angle X-Ray Scattering (WAXS) results demonstrate the high degree of crystallinity present in all the polyesters.Contract grant sponsor: Consejo Nacional de Ciencia y Tecnología (CONACyT); contract grant number: SEP-2004- C01-47173E. Contract grant sponsor: Consejo de Ciencia y Tecnología del Estado de Guanajuato (CONCYTEG). Contract grant sponsor: Universidad de Guanajuatato.Peer reviewe

Comparative Study of Starch Fibers Obtained by Electro-spinning of Indigenous, Commercial and Cationic Potato Starch

By using the electro-spinning process on natural polymers, it is possible to obtain biodegradable membranes with potential applications in filters and scaffolds for tissue engineering. In this study, a comparison was made between the respective chemical, physical and thermal properties of the fibers from two sources of starch: One derived from a local, indigenous variety of potato (Diacol Capiro), native to the Boyacá region of Colombia (from here on referred to as “local starch”); the other, commercially available starch. A cationization of fibers was also carried out on the two starches. Chemical, physical and thermal properties were analyzed by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (DRX), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed the fibers were cationized with a highly amorphous state, with a heat resistance of 300°C from physicochemical changes generated in the fibers