Influence of a Zeolite-Based Cascade Layer on Fischer–Tropsch Fuels Production over Silicon Carbide Supported Cobalt Catalyst

In this work, selective production of middle distillate from synthesis gas was conducted over a cascade catalytic system in a single unit. Co/β-SiC was chosen as an efficient Fischer–Tropsch synthesis (FTS) catalyst (first layer) while proton-type H-ZSM-5 and H-βeta zeolites (second layer) were tested for the subsequent hydroprocessing to produce middle distillate from waxes. Moreover, in order to compare, a prior FTS reference experiment was performed. Catalytic materials were characterized by means of Atomic Absorption, Thermogravimetric analysis, X-Ray diffraction, N₂ adsorption–desorption, Temperature-Programmed Reduction and Temperature-Programmed Desorption. From catalytic results, a distinguishable enhancement of commercial fuels products was observed under the proposed cascade operation compared to the stand-alone configuration or physical mixture. Regardless the zeolite type, FTS over Co/β-SiC with subsequent upgrading was demonstrated to result in the complete elimination of waxes, solving the main weakness of a conventional fixed-bed reactor. Moreover, apart from a selective production of gasoline, the proposed concept provided a significant enhancement of both kerosene and diesel yields, particularly when zeolite H-βeta is incorporated to the cascade system due to its mild acidity and larger pore size.     

Impact of nitrogen doping of carbon nanospheres on the nickel-catalyzed hydrogenation of butyronitrile

Three nickel catalysts supported on carbon and nitrogen-doped carbon nanospheres have been prepared by deposition-precipitation (DP) with urea (ca. 2% w/w). The nanospheres were prepared by thermal pyrolysis of benzene (CNS_B), aniline (CNS_A) and nitrobenzene (CNS_N) and characterized by transmission electron microscopy (TEM), N₂ adsorption–desorption, temperature-programmed oxidation (TPO), X-ray diffraction (XRD), elemental (CHN) analysis, X-ray photoelectron spectroscopy (XPS), temperature-programmed decomposition (TPD) and acid/base titrations, revealing different graphitic characteristics and different distribution of nitrogen (when present) functionalities. Upon Ni introduction, the catalysts were characterized by temperature-programmed reduction (TPR), XRD and TEM. Surface area weighted mean Ni particle diameters (post activation at 603 K) were in the range 10.5–18.2 nm. Ni particle size exhibited a big dependence on CNS nitrogen doping, where nitrogen introduction, essentially in the quaternary form, enhanced metal sintering by enriching the surface electron density of the support. The catalysts were tested in the gas phase hydrogenation of butyronitrile (T = 493 K). Extracted specific reaction rates in the steady state followed the sequence: Ni/CNS_B < Ni/CNS_A < Ni/CNS_N. When the active metal was physically mixed with the support, the following sequence was obtained: Ni + CNS_B < Ni + CNS_A < Ni + CNS_N. Our results demonstrate that doping carbon nanospheres with nitrogen strongly impacts on reactant adsorption and metal sintering, both critical aspects in the hydrogenation of nitriles. Selectivity was not sensitive to the support (or the physical mixture) employed and was in all cases close to 100% to the primary amine.     

Mobilization of phosphorus from iron ore by the bacterium Burkholderia caribensis FeGL03

The bacterium Burkholderia caribensis FeGL03, isolated from a Brazilian high-phosphorus iron ore, was used to mobilize the phosphate contained in the same ore. The phosphate-mobilizing ability of the organism was tested in shake-flask cultures containing sterilized crushed iron ore in a chemically-defined liquid culture medium containing glucose (1 g/l) as carbon source and no phosphorus source except the ore itself. Phosphate removal from the ore was determined by measuring the residual phosphate contained in the ore after the bacterial treatment. The time course of the phosphate mobilization process was determined with two different particle sizes (2.0 mm and 0.2 mm mean size) of the crushed ore under conditions of unlimited and limited air exchange. Between 5% and 20% of the phosphorus originally contained in the ore was mobilized in 21 days of treatment. Other variables such as dissolved Fe, pH and cell counts were also monitored throughout the trials. It was also found that this bacterium accumulated gluconic acid in the spent broth. Scanning electron microscopy, revealed biofilms on the ore surface as a result of the production of exopolymeric substances (EPS). Extraction of the EPS from the cultures and its analysis by Fourier transform infrared techniques revealed the presence of molecular functionalities capable of interacting with the ore surface and with the iron dissolved in the medium. It was found that dense biofilms, formed under limited air exchange, resulted in lower phosphate mobilization from the ore than under unlimited air exchange. This was found to be a consequence of a dynamic process of iron and phosphate re-precipitation within the formed biofilms.     

Effect of inclination on gas-fluidized beds of fine cohesive powders

Results are presented of an experimental investigation on how bed inclination affects the fluidization and sedimentation behavior of fine cohesive particles. In contrast with the expected Geldart C behavior, and due to self-agglomeration, these fine particles are uniformly fluidized by gas in a vertically oriented bed, displaying a fluid-like regime and expanding smoothly as the gas velocity is increased. When the gas flow supply to the bed is suddenly stopped, the initial sedimentation velocity of the vertically oriented bed is similar to the fluidizing gas velocity as corresponds to uniform fluidization. The main effect of inclination is to induce fluidization heterogeneity. The local gas velocity increases in the adjacent region to the upper wall at the expense of the region adjacent to the lower wall. This situation anticipates the onset of local bubbling in the region adjacent to the upper wall. Meanwhile the region adjacent to the lower wall remains in a solid-like state and does not reach the fluid-like state until values of the gas flow are applied much higher than those needed in a vertical fluidized bed. As a consequence, the expansion and fluidization uniformity of the tilted bed are hindered. If the gas supply to the inclined bed is suddenly stopped, and because of induced heterogeneity, sedimentation takes place at a decreased rate as compared with sedimentation velocity in the uniformly fluidized vertical bed.     

Insulin receptor substrate (IRS) proteins IRS-1 and IRS-2 differential signaling in the insulin/insulin-like growth factor-I pathways in fetal brown adipocytes

In the present study we have investigated the contribution of the insulin receptor substrate proteins (IRS-1 and IRS-2) to the insulin/insulin like growth factor I (IGF-I)-signaling pathways in fetal rat brown adipocytes, a model that expresses both insulin and IGF-I receptors. Insulin/IGF-I rapidly stimulated IRS-1 and IRS-2 tyrosine phosphorylation, their association with p85alpha, and IRS-1- and IRS-2-associated phosphatidylinositol (PI) 3-kinase activation to the same extent, the effect of insulin being stronger than the effect of IGF-I at the same physiological dose (10 nM). Furthermore, insulin/IGF-I stimulated IRS-1-associated Grb-2 phosphorylation. However, IRS-2-associated Grb-2 phosphorylation was barely detected. Pull-down experiments with glutathione-S-transferase-fusion proteins containing SH2-domains of p85alpha revealed a strong association between IRS-1 and IRS-2 with p85alpha in response to insulin/IGF-I, the insulin effect being stronger than IGF-I. However, the Grb-2-SH2 domain showed functional differences. While a strong association between IRS-1/Grb-2 was found, IRS-2/Grb-2 association was virtually absent in response to insulin/IGF-I, as also demonstrated in competition studies with a phosphopeptide containing the phosphotyrosine 895 residue within the putative Grb-2-binding domain. Finally, insulin/IGF-I stimulated tyrosine phosphorylation of the three SHC proteins (46, 52, and 66 kDa). Moreover, insulin/IGF-I markedly increased the amount of Grb-2-associated SHC proteins by the same extent. Our results suggest that both IRS-1 and IRS-2 are required for phosphatidylinositol 3-kinase activation that leads to adipogenic and thermogenic differentiation of fetal brown adipose tissue; meanwhile, IRS-1 and SHC, but not IRS-2, associate with Grb-2 leading to the ras-mitogen-activated protein kinase-signaling pathway required for fetal brown adipocyte proliferation.     

Prognostic value of immunophenotypic detection of minimal residual disease in acute lymphoblastic leukemia

PURPOSE: The identification of immunophenotypic aberrancies through multiparametric flow cytometry makes the differentiation between normal and leukemic cells relatively simple and quick, and is therefore an attractive method for the investigation of minimal residual disease (MRD). In this report, we have analyzed the impact on relapse and relapse-free survival (RFS) of detecting immunophenotypical aberrant cells in acute lymphoblastic leukemia (ALL) patients in cytomorphologic complete remission (CR). MATERIALS AND METHODS: Two hundred eleven bone marrow (BM) samples from 53 consecutive ALL (37 precursor B-ALL and 16 T-ALL) patients were analyzed. The only selection criteria were to have at least one aberrant immunophenotypic feature at diagosis and to have achieved cytomorphologic CR after induction therapy. For MRD detection, all follow-up samples were analyzed with triple labelings using a two-step acquisition procedure, in which 106 cells were screened for the possible persistence of residual leukemic cells with the same phenotypic aberrancy as that identified diagnosis. RESULTS: Patients who displayed a gradual increase in MRD levels showed a higher relapse rate (90% v22%; P < .00001) and shorter median RFS (12 months v not reached; P < .0001) than those with stable or decreasing MRD levels. This adverse prognostic influence also was observed when children and adults, as well as B-ALL and T-ALL patients, were analyzed separately. An MRD level > or = or greater than 10(-3) discriminated two risk groups of ALL patients with significantly different relapse rates and RFS at all treatment phases (end of induction, consolidation, maintenance, and out of treatment). CONCLUSION: Multiparametric flow cytometry of MRD in ALL patients is a valuable tool for relapse prediction and for the identification of a cohort of patients with very poor prognosis.     

Structure–function relationships of fullerene esters in polymer solar cells: unexpected structural effects on lifetime and efficiency

We report both transport measurements and spectroscopic data of polymer/fullerene blend photovoltaics using a small library of fullerene esters to correlate device properties with a range of functionality and structural diversity of the ester substituent. We observe that minor structural changes can lead to significant and surprising differences in device efficiency and lifetime. For example we have found that isomeric R‐groups in the fullerene ester‐based devices we have studied have dramatically different efficiencies. The characteristic lifetimes derived from both transport and spectroscopic measurements are generally comparable; however, some more rapid effects in specific fullerene esters are not observed spectroscopically. It is apparent from our results that each fullerene derivative requires re‐optimization to reveal the best device performance. Furthermore we conclude that a library approach is essential for evaluating the effects of structural differences in the constituent molecules and serves as important device optimization method that is not being currently employed in photovoltaic investigations. Copyright © 2015 John Wiley & Sons, Ltd.     

Assessment of nutritional compounds and antinutritional factors in pea (Pisum sativum) seeds

The nutrient and antinutritional factor content of 18 pea lines was studied. The following levels were found: non‐protein nitrogen 5.2–10.2 g kg^?1 DM, protein nitrogen 35.3–42.4 g kg^?1 DM, lysine 50.7–76.3 g kg^?1 protein DM, histidine 17.8–24.8 g kg^?1 protein DM, tyrosine 22.6–30.0 g kg^?1 protein DM, protein 25.9–31.9% DM, in vitro protein digestibility 89.3–95.6%, vitamin B₁ 5.9–10.3 mg kg^?1 DM, vitamin B₂ 1.1–3.7 mg kg^?1 DM, sucrose 11.6–25.4 g kg^?1 DM, raffinose 4.1–10.3 g kg^?1 DM, stachyose 10.7–26.7 g kg^?1 DM, verbascose 0.0–26.7 g kg^?1 DM, total α‐galactosides 22.6–63.4 g kg^?1 DM, trypsin inhibitor activity 0.8–8.4 TIU mg^?1 DM, inositol hexaphosphate 2.3–6.5 g kg^?1 DM, inositol pentaphosphate 0.1–1.8 g kg^?1 DM and total inositol phosphates 2.8–7.1 g kg^?1 DM. Peas with yellow cotyledons had the highest trypsin inhibitor activities, those with light green cotyledons had the highest lysine contents, and those with dark green cotyledons were the richest in vitamins B₁ and B₂. Peas with brown testae had the lowest verbascose and sucrose contents, while they were the richest in inositol hexaphosphate. Smaller peas were characterised by the highest protein nitrogen contents as well as the highest contents of vitamins B₁ and B₂, verbascose and inositol pentaphosphate. Peas of medium size showed the lowest verbascose, α‐galactoside and vitamin B₂ contents. Bigger peas showed the lowest inositol pentaphosphate contents. © 2003 Society of Chemical Industry