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The synthesis of a low particle size carbon molecular sieve (CMS) adsorbent was optimized for the O2/N2 separation. The best performing CMS displayed an O2/N2 adsorption kinetic selectivity of 123 and an inverse of apparent diffusion time constant of ca. 9 × 10−2 s−1; these are the highest values reported for an oxygen chemisorption stabilized sample. The adsorbent was prepared from the carbonization of a cellulosic precursor at 1000 °C followed by milling and stabilization steps. The sample structure, morphology and performance were further examined by scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, CO2 adsorption and adsorption capacity and kinetics of O2, N2, Ar and SF6 at 25 °C. SEM micrographs showed very fine powder particles with stomas. CO2 adsorption isotherms revealed that the CMS adsorbent has a well-developed microporous structure. The obtained results were well above the ones reported on literature for similar conditions opening the door for the preparation of stable carbon molecular sieve adsorbents with extraordinary O2/N2 separation performance.

Novel carbon molecular sieve membranes with high separation performance and stability in the presence of humidified streams were prepared from an optimized ionic liquid-regenerated cellulose precursor, in a single carbonization step. Membranes prepared at two different carbonization end temperatures (550 degrees C and 600 degrees C) were analyzed through scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, carbon dioxide adsorption and permeation experiments. The prepared membranes exhibited uniform thickness of approximately 20 mu m and a well-developed microporous structure. The permeation performance of these carbon molecular sieve membranes was above the Robeson upper bound curve for polymeric membranes. In particular, the membrane prepared at 550 degrees C end temperature exhibited permeability to oxygen of 5.16 barrer and O-2/N-2 ideal selectivity of 32.3 and permeability to helium of 126 barrer and He/N-2 ideal selectivity of 788; besides, permeation experiments performed in the presence of ca. 80% relative humidity showed that humidity does not originate pore blockage. These results open the door for the preparation of tailor made precursors that originate carbon molecular sieve membranes with extraordinary separation performances, mechanical resistance and stability.

Membrane technology is considered to be one of the most efficient processes for CO2 separation/removal from different sources. Membranes are environmentally friendly, easy to scale up, energy efficient, and already used in various gas and liquid separation processes. Among different types of membranes, polymeric facilitated transport membranes have gained a significant interest due to the high CO2 permeability and remarkable high selectivities versus H2, N2, CO, and CH4. The selectivity of these membranes is related to the reversible chemisorption of CO2, which provides the facilitated transport, and the low permeability to the nonreacting species. In this chapter, the facilitated transport mechanism is described and amine-based fixed-site-carrier and ionic liquid-based facilitated transport membranes for CO2/H2 separation are discussed.

Supported composite alumina-carbon molecular sieve membranes (c-CMSM) were prepared from in house prepared novolac phenolic resin loaded with boehmite nanoparticles in a single dipping-drying-carbonization step. A porous a-alumina tube support was dipped into a N-methyl-2-pyrrolidone solution containing polymerized novolac resin loaded with boehmite, subsequently dried at 100 degrees C and carbonized at 500 degrees C under nitrogen environment. The structure, morphology and performance of the membranes were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), carbon dioxide adsorption and permeation of N-2, O-2, He, H-2 and CO2. SEM showed carbon membranes with a thin and very uniform layer with a thickness of ca. 3 mu m CO2 adsorption isotherms indicated that the produced carbon membranes presented a microporous structure. The c-CMSM exhibited good gas separation properties. The permselectivity surpass the Robeson upper bound for polymeric membranes, especially regarding ideal permselectivities of pairs H-2/N-2 = 117, and He/O-2 = 49. Aging effects were observed after membrane exposure to ambient air. However with a thermal treatment under nitrogen atmosphere the permeance of nitrogen increases. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

The dopaminergic antagonist drug Domperidone has immunomodulatory effects. We investigated the effects of repeated Domperidone treatment in a model of Lypopolyssacharide (LPS)-induced acute lung inflammation. Adult C57BL/6J mice were treated with either Vehicle or Domperidone for 5days, and challenged intranasally with LPS in the following day. The behavior of mice was analyzed in the open field and elevated plus-maze test before and 24h after LPS challenge. The bronchoalveolar lavage fluid, blood and lung tissue were collected 24h and 48h after LPS challenge. Domperidone treatment increased LPS-induced tumor necrosis factor (TNF) and interleukin (IL)-6 production in the bronchoalveolar lavage fluid, without altering tissue damage and the number of immune cells in the lungs and circulation. Locomotor and anxiety-like behavior were unchanged after Domperidone and/or LPS treatment. Cytokine data indicate that Domperidone promotes a change in activity of other cell types, likely alveolar epithelial cells, without affecting immune cell migration in the present model. Due to the role of these cytokines in progression of inflammation, Domperidone treatment may exacerbate a subsequent inflammatory injury.

We investigated the effect of dexamethasone during the last week of pregnancy on glucose and lipid metabolism in male offspring. Twelve-week old offspring were evaluated after fasting for 12-hours (physiological) and 60-hours (prolonged). Physiological fasting resulted in glucose intolerance, decreased glucose clearance after pyruvate load and increased PEPCK expression in rats born to dexamethasone-treated mothers (DEX). Prolonged fasting resulted in increased glucose tolerance and increased glucose clearance after pyruvate load in DEX. These modulations were accompanied by accumulation of hepatic triglycerides (TG). Sixty-hour fasted DEX also showed increased citrate synthase (CS) activity, ATP citrate lyase (ACLY) content, and pyruvate kinase 2 (pkm2), glucose transporter 1 (slc2a1) and lactate dehydrogenase-a (ldha) expressions. Hepatic AKT2 was increased in 60-hour fasted DEX, in parallel with reduced miRNAs targeting the AKT2 gene. Altogether, we show that metabolic programming by prenatal dexamethasone is characterized by an unexpected hepatic TG accumulation during prolonged fasting. The underlying mechanism may depend on increased hepatic glycolytic flux due to increased pkm2 expression and consequent conversion of pyruvate to non-esterified fatty acid synthesis due to increased CS activity and ACLY levels. Upregulation of AKT2 due to reduced miRNAs may serve as a permanent mechanism leading to increased pkm2 expression.

The liver plays an essential role in maternal metabolic adaptation during late pregnancy. With regard to lipid metabolism, increased secretion of very low-density lipoprotein (VLDL) is characteristic of late pregnancy. Despite this well-described metabolic plasticity, the molecular changes underlying the hepatic adaptation to pregnancy remain unclear. As AMPK is a key intracellular energy sensor, we investigated whether this protein assumes a causal role in the hepatic adaptation to pregnancy. Pregnant Wistar rats were treated with vehicle or AICAR (5-aminoimidazole-4-carboxamide ribonucleotide) for 5 days starting at gestational day 14. At the end of treatment, the rats were subjected to an intraperitoneal pyruvate tolerance test and in situ liver perfusion with pyruvate. The livers were processed for Western blot analysis, quantitative PCR, thin-layer chromatography, enzymatic activity, and glycogen content measurements. Blood biochemical profiles were also assessed. We found that AMPK and ACC phosphorylation were reduced in the livers of pregnant rats in parallel with a reduced level of hepatic gluconeogenesis of pyruvate. This effect was accompanied by both a reduction in the levels of hepatic triglycerides (TG) and an increase in circulating levels of TG. Treatment with AICAR restored hepatic levels of TG to those observed in nonpregnant rats. Additionally, AMPK activation reduced the upregulation of genes related to VLDL synthesis and secretion observed in the livers of pregnant rats. We conclude that the increased secretion of hepatic TG in late pregnancy is concurrent with a transcriptional profile that favors VLDL production. This transcriptional profile results from the reduction in hepatic AMPK activity. ispartof: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology vol:307 issue:9 pages:R1146-R1156 ispartof: location:United States status: published

Carbon molecular sieve membranes (CMSM) were prepared on α-alumina supports by carbonization of a resorcinol–formaldehyde resin loaded with boehmite. Two series of carbon membranes produced at 500 °C and 550 °C carbonization end temperatures were prepared. The influence of the carbonization end temperature on the structure, morphology and performance of the membranes was examined by scanning electron microscopy, thermogravimetric analysis, CO2 adsorption and permeation to N2, O2, He, H2 and CO2 at temperatures from 25 °C to 120 °C. SEM photographs showed carbon membranes with a thin and very uniform layer and a thickness of ca. 3 µm. Carbon dioxide adsorption isotherms revealed that all the produced carbon membranes have a well-developed microporous structure. Nevertheless, the membranes carbonized at 550 °C have more ultramicropores and a narrower pore size distribution. The permselectivity of CMSM prepared at this temperature surpasses the Robeson upper bound for polymeric membranes, especially regarding ideal selectivities of pairs O2/N2 (O2 permeation rate: 9.85×10−10 mol m−2 s−1 Pa−1 and ideal selectivity: >11.5), H2/N2 (H2 permeation rate: 5.04×10−8 mol m−2 s−1 Pa−1 and ideal selectivity: >586) and He/N2 (He permeation rate: 4.68×10−8 mol m−2 s−1 Pa−1 and ideal selectivity: >544).

For some time, carbon molecular sieve membranes (CMSMs) have been promoted as energy-efficient candidates for gas separation due to their high selectivity, permeability, and stability in chemically aggressive environments. Nevertheless, these membranes have not yet been made into commercial products due to a significant decrease in performance when exposed to humidity and/or oxygen. Herein, disruptive CMSMs with extremely high separation performance and stability, even in the presence of humidity, are reported. The carbon membranes are prepared from a renewable, low-cost precursor with a single carbonization step. Water vapor adsorption/desorption studies demonstrate that these membranes have a linear water vapor adsorption isotherm, characteristic of a homogeneous distribution of hydrophilic sites on the pore surfaces, allowing for water molecules to hop continuously between sites and avoiding the formation of pore-blocking water clusters. These results are a breakthrough toward bringing this new type of membrane to a commercial level.

It is known that the circadian rhythm in hepatic phosphoenolpyruvate carboxykinase expression (a limiting catalytic step of gluconeogenesis) and hepatic glucose production is maintained by both daily oscillation in autonomic inputs to the liver and night feeding behavior. However, increased glycemia and reduced melatonin (Mel) levels have been recently shown to coexist in diabetic patients at the end of the night period. In parallel, pinealectomy (PINX) is known to cause glucose intolerance with increased basal glycemia exclusively at the end of the night. The mechanisms that underlie this metabolic feature are not completely understood. Here, we demonstrate that PINX rats show night-time hepatic insulin resistance characterized by reduced insulin-stimulated RAC-α serine/threonine-protein kinase phosphorylation and increased phosphoenolpyruvate carboxykinase expression. In addition, PINX rats display increased conversion of pyruvate into glucose at the end of the night. The regulatory mechanism suggests the participation of unfolded protein response (UPR), because PINX induces night-time increase in activating transcription factor 6 expression and prompts a circadian fashion of immunoglobulin heavy chain-binding protein, activating transcription factor 4, and CCAAT/enhancer-binding protein-homologous protein expression with Zenith values at the dark period. PINX also caused a night-time increase in Tribble 3 and regulatory-associated protein of mammalian target of rapamycin; both were reduced in liver of PINX rats treated with Mel. Treatment of PINX rats with 4-phenyl butyric acid, an inhibitor of UPR, restored night-time hepatic insulin sensitivity and abrogated gluconeogenesis in PINX rats. Altogether, the present data show that a circadian oscillation of UPR occurs in the liver due to the absence of Mel. The nocturnal UPR activation is related with night-time hepatic insulin resistance and increased gluconeogenesis in PINX rats. ispartof: Endocrinology vol:152 issue:4 pages:1253-63 ispartof: location:United States status: published

Composite carbon molecular sieve membranes (c-CMSM) were prepared in a single dipping–drying–carbonization step from phenolic resin solutions (12.5–15 wt.%) loaded with boehmite nanoparticles (0.5–1.2 wt.%). A carbon matrix with well-dispersed Al2O3 nanowires was formed from the decomposition of the resin and dehydroxylation of boehmite. The effect of the carbon/Al2O3 ratio on the porous structure of the c-CMSM was accessed based on the pore size distribution and gas permeation toward N2, O2, CO2, He, H2, C3H6 and C3H8. c-CMSM with higher carbon/Al2O3 ratios had a more open porous structure, exhibiting higher permeabilities and lower permselectivities. c-CMSM performance was above the upper bound curves for polymeric membranes for several gas pairs, particularly for C3H6/C3H8 (permeability toward C3H6 of 420 barrer and permselectivity of 18.1 for a c-CMSM with carbon/Al2O3 ratio of 4.4). Unsupported films were also prepared (carbon/Al2O3 ratio 7.3) and crushed into small flakes. Equilibrium isotherms of H2, N2, O2, CO2, C3H8 and C3H6 at 293 K were determined on these flakes to obtain the kinetic and adsorption selectivities toward gas pairs of interest; obtained adsorption and diffusion coefficients accurately predicted the permeabilities of all studied gases except CO2 (experimental and predicted permeabilities of 1148 and 154 barrer, respectively).

Excess of glucocorticoids (GCs) during pregnancy is strongly associated with the programming of glucose intolerance in the offspring. However, the impact of high GC levels on maternal metabolism is not clearly documented. This study aimed to test the hypothesis that mothers exposed to elevated levels of GCs might also display long-term disturbances in glucose homeostasis. Dexamethasone (DEX) was administered noninvasively to the mothers via drinking water between the 14th and the 19th days of pregnancy. Mothers were subjected to glucose and insulin tolerance tests at 1, 2, 3, 6, and 12 mo postweaning. Pregnant rats not treated with DEX and age-matched virgin rats were used as controls. Pancreatic islets were isolated at the 20th day of pregnancy and 12 mo postweaning in order to evaluate glucose-stimulated insulin secretion. The expression of the miR-29 family was also studied due to its responsiveness to GCs and its well-documented role in the regulation of pancreatic β-cell function. Rats treated with DEX during pregnancy presented long-term glucose intolerance and impaired insulin secretion. These changes correlated with 1) increased expression of miR-29 and its regulator p53, 2) reduced expression of syntaxin-1a, a direct target of miR-29, and 3) altered expression of genes related to cellular senescence. Our data demonstrate that the use of DEX during pregnancy results in deleterious outcomes to the maternal metabolism, hallmarked by reduced insulin secretion and glucose intolerance. This maternal metabolic programming might be a consequence of time-sustained upregulation of miR-29s in maternal pancreatic islets.

Recent efforts of bone repair focus on development of porous scaffolds for cell adhesion and proliferation. Collagen-nanohydroxyapatite (HA) scaffolds (70:30; 50:50; and 30:70 mass percentage) were produced by cryogelation technique using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide as crosslinking agents. A pure collagen scaffold was used as control. Morphology analysis revealed that all cryogels had highly porous structure with interconnective porosity and the nanoHA aggregates were randomly dispersed throughout the scaffold structure. Chemical analysis showed the presence of all major peaks related to collagen and HA in the biocomposites and indicated possible interaction between nanoHA aggregates and collagen molecules. Porosity analysis revealed an enhancement in the surface area as the nanoHA percentage increased in the collagen structure. The biocomposites showed improved mechanical properties as the nanoHA content increased in the scaffold. As expected, the swelling capacity decreased with the increase of nanoHA content. In vitro studies with osteoblasts cells showed that they were able to attach and spread in all cryogels surfaces. The presence of collagen-nanoHA biocomposites resulted in higher overall cellular proliferation compared to pure collagen scaffold. A statistically significant difference between collagen and collagen-nanoHA cryogels was observed after 21 day of cell culture. These innovative collagen-nanoHA cryogels could have potentially appealing application as scaffolds for bone regeneration. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.