399 research outputs found
Experimental and Simulation Study of Adsorption in Postcombustion Conditions Using a Microporous Biochar. 1. CO2 and N2 Adsorption
The influence of N2 on CO2 adsorption was evaluated using a microporous biochar with a narrow pore size distribution. The adsorption isotherms of pure CO2 and N2 were measured at 0, 30, 50, and 70 °C up to 120 kPa and fitted to the Toth adsorption model. Dynamic breakthrough experiments were carried out in a fixed-bed adsorption unit using binary mixtures with compositions representative of different postcombustion streams (8–30% CO2) from ambient temperature to 70 °C. Dynamic adsorption experiments were simulated to validate the mathematical model of the adsorption process, as a necessary step for its later use for process design. The Ideal Adsorption Solution (IAS) theory, based on the pure component adsorption models, was used to account for competitive adsorption with satisfactory results. The information gathered in the present work will be used to extend the validity of the model to the adsorption of postcombustion streams containing H2O in part 2.Work was carried out with financial support from the HiPerCap
Project of the European Union 7th Framework Programme
FP7 (2007-2013; Grant Agreement number: 60855). M.G.P.
acknowledges funding from the CSIC (JAE-Doc program
cofinanced by the European Social Fund). N.Q. acknowledges
funding from the Government of the Principado de Asturias
(Severo Ochoa Program). The authors also appreciate the
support from the technical consultants of AspenTechnology
Inc., M.M. and E.L.Peer reviewe
Microstructured reactor as a pre-turbo catalytic converter
The idea of a structured catalytic converter
placed immediately after engine exhaust valves, thus
operating on high gas temperature and velocity, is
explored. The assumption is that major part of the reactor
operates in the entry region where Nusselt and Sherwood
numbers are highly enhanced. In this work, flow resistances
as well as heat and mass transfer coefficients were studied
for gas velocities exceeding 50 m/s. Consequently, the
transition range (between laminar and turbulent flows) was
reached. The comparison with classic monolith has shown
significant improvement in heat or mass transfer paid by
slight increase in flow resistance
Prolactin Receptor Signaling Is Essential for Perinatal Brown Adipocyte Function: A Role for Insulin-like Growth Factor-2
BACKGROUND: The lactogenic hormones prolactin (PRL) and placental lactogens (PL) play central roles in reproduction and mammary development. Their actions are mediated via binding to PRL receptor (PRLR), highly expressed in brown adipose tissue (BAT), yet their impact on adipocyte function and metabolism remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: PRLR knockout (KO) newborn mice were phenotypically characterized in terms of thermoregulation and their BAT differentiation assayed for gene expression studies. Derived brown preadipocyte cell lines were established to evaluate the molecular mechanisms involved in PRL signaling on BAT function. Here, we report that newborn mice lacking PRLR have hypotrophic BAT depots that express low levels of adipocyte nuclear receptor PPARgamma2, its coactivator PGC-1alpha, uncoupling protein 1 (UCP1) and the beta3 adrenoceptor, reducing mouse viability during cold challenge. Immortalized PRLR KO preadipocytes fail to undergo differentiation into mature adipocytes, a defect reversed by reintroduction of PRLR. That the effects of the lactogens in BAT are at least partly mediated by Insulin-like Growth Factor-2 (IGF-2) is supported by: i) a striking reduction in BAT IGF-2 expression in PRLR KO mice and in PRLR-deficient preadipocytes; ii) induction of cellular IGF-2 expression by PRL through JAK2/STAT5 pathway activation; and iii) reversal of defective differentiation in PRLR KO cells by exogenous IGF-2. CONCLUSIONS: Our findings demonstrate that the lactogens act in concert with IGF-2 to control brown adipocyte differentiation and growth. Given the prominent role of brown adipose tissue during the perinatal period, our results identified prolactin receptor signaling as a major player and a potential therapeutic target in protecting newborn mammals against hypothermia
Mechanisms and models of somatic cell reprogramming
Whitehead Institute for Biomedical Research (Jerome and Florence Brill Graduate Student Fellowship)National Institutes of Health (U.S.) (US NIH grant RO1-CA087869)National Institutes of Health (U.S.) (US NIH grant R37-CA084198)National Science Foundation (U.S.) (NSF Graduate Research Fellowship)National Institutes of Health (U.S.) ((NIH) Kirschstein National Research Service Award,1 F32 GM099153-01A1)Vertex Pharmaceuticals Incorporated (Vertex Scholar
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An integrated bioinformatics analysis reveals divergent evolutionary pattern of oil biosynthesis in high- and low-oil plants
Seed oils provide a renewable source of food, biofuel and industrial raw materials that is important for humans. Although many genes and pathways for acyl-lipid metabolism have been identified, little is known about whether there is a specific mechanism for high-oil content in high-oil plants. Based on the distinct differences in seed oil content between four high-oil dicots (20~50%) and three low-oil grasses (<3%), comparative genome, transcriptome and differential expression analyses were used to investigate this mechanism. Among 4,051 dicot-specific soybean genes identified from 252,443 genes in the seven species, 54 genes were shown to directly participate in acyl-lipid metabolism, and 93 genes were found to be associated with acyl-lipid metabolism. Among the 93 dicot-specific genes, 42 and 27 genes, including CBM20-like SBDs and GPT2, participate in carbohydrate degradation and transport, respectively. 40 genes highly up-regulated during seed oil rapid accumulation period are mainly involved in initial fatty acid synthesis, triacylglyceride assembly and oil-body formation, for example, ACCase, PP, DGAT1, PDAT1, OLEs and STEROs, which were also found to be differentially expressed between high- and low-oil soybean accessions. Phylogenetic analysis revealed distinct differences of oleosin in patterns of gene duplication and loss between high-oil dicots and low-oil grasses. In addition, seed-specific GmGRF5, ABI5 and GmTZF4 were predicted to be candidate regulators in seed oil accumulation. This study facilitates future research on lipid biosynthesis and potential genetic improvement of seed oil content
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