Polyphosphates and pyrophosphates of pentopyranoses and pentofuranoses as allosteric effectors of human hemoglobin: synthesis, molecular recognition, and oxygen release

Perphosphorylated pentopyranoses and pentofuranoses were synthesized from parent carbohydrates as potential allosteric effectors of hemoglobin (Hb). The construction of seven- and eight-membered cyclic pyrophosphates was also carried out successfully on most of the pentoses. All final compounds were tested for their efficiency on oxygen release from human Hb. Most proved to be efficient allosteric effectors, some of them with an affinity toward Hb and an effect on oxygen release from Hb approaching that of myo-inositol hexakisphosphate, which is one of the most active allosteric effectors of Hb. The efficacy was higher for free phosphates than for pyrophosphates.     

Effective drag on spheres immersed in a fluidized bed at minimum fluidization—Influence of bulk solids properties

The aims of this work are to elucidate the effects that bulk solids properties have on the effective drag experienced by large spheres immersed in an emulsion of group-B solids under minimum fluidization conditions and to analyze the ways in which the different suspensions react towards different applied shear rates. To investigate this, magnetic particle tracking was applied to resolve the trajectory of falling-sphere measurements in which the size, density, and sphericity of the bulk solids were varied as well as the size and density of the spherical tracers. The resulting experimental scope included both rising and sinking tracers as well as full segregation and in-bed stagnation of the tracers. The set-up provided highly resolved tracer trajectories, from which the drag experienced by the sphere can be calculated. For sinking tracers, the results showed that an increase in bulk solids size, angularity, and density reduced the terminal velocity of the sphere. This effect correlated well with the bed expansion and Hausner ratio, indicating that a reduced void space among the bulk solids is the main reason for the increase in motion resistance. At lower shear rates, namely, during the de-acceleration towards the stagnant state, beds of larger, more angular, or denser bulk solids yield lower levels of shear stress. The angle of repose of the bulk solids correlated with the rate at which the emulsion thins with increasing shear rate. For rising tracers, shear stress did not show any significant dependency on the properties of the bulk solids.     

Loss of Vps54 Function Leads to Vesicle Traffic Impairment,Protein Mis-Sorting and Embryonic Lethality

The identification of the mutation causing the phenotype of the amyotrophic lateral sclerosis (ALS) model mouse, wobbler, has linked motor neuron degeneration with retrograde vesicle traffic. The wobbler mutation affects protein stability of Vps54, a ubiquitously expressed vesicle-tethering factor and leads to partial loss of Vps54 function. Moreover, the Vps54 null mutation causes embryonic lethality, which is associated with extensive membrane blebbing in the neural tube and is most likely a consequence of impaired vesicle transport. Investigation of cells derived from wobbler and Vps54 null mutant embryos demonstrates impaired retrograde transport of the Cholera-toxin B subunit to the trans-Golgi network and mis-sorting of mannose-6-phosphate receptors and cargo proteins dependent on retrograde vesicle transport. Endocytosis assays demonstrate no difference between wobbler and wild type cells, indicating that the retrograde vesicle traffic to the trans-Golgi network, but not endocytosis, is affected in Vps54 mutant cells. The results obtained on wobbler cells were extended to test the use of cultured skin fibroblasts from human ALS patients to investigate the retrograde vesicle traffic. Analysis of skin fibroblasts of ALS patients will support the investigation of the critical role of the retrograde vesicle transport in ALS pathogenesis and might yield a diagnostic prospect.     

Organic milk improves Bifidobacterium lactis counts and bioactive fatty acids contents in fermented milk

In functional dairy products, polyunsaturated fatty acids such as, conjugated linoleic acid (CLA) and α-linolenic acid (ALA) have been highlighted for their benefits related to prevention of some chronic diseases. In order to study the effect of type of milk (conventional vs. organic, characterized by a specific fatty acid composition), Bifidobacterium animalis subsp. lactis (BB12, B94, BL04 and HN019) counts, acidification activity and chemical composition (pH, lactose, lactic acid contents and fatty acids profile) were investigated before fermentation and after 24 h of products stored at 4 °C. Organic and conventional milk influenced acidification performance and bacteria counts, which was strain-dependent. Higher counts of BB12 were observed in organic milk, whereas superior counts of BL04 were found in conventional milk. Organic fermented milk showed lower levels in saturated fatty acids (FA) and higher in monounsaturated FA contents. Similarly, among bioactive FA, organic fermented milks have higher amounts of trans vaccenic acid (TVA–C18:1t), conjugated linoleic acid (CLA) and slightly higher contents of α-linoleic acid (ALA).     

Proteomic and peptidomic characterisation of beer: Immunological and technological implications

In this study, the protein and peptide fractions of two commercial Italian barley malt beers, made with different processes by the same producer, have been analysed with a combined immunochemical and mass spectrometry approach. The “gluten” content of beer samples, measured with the R5 monoclonal antibody, was below the caution limit proposed by the Codex Alimentarius for gluten-free foods. The proteomic approach allowed to identify a 17 kDa avenin-like protein partially homologous to hordeins, that was particularly abundant in foam, in addition to the already reported barley albumins (Z₄-barley and ns-LTPs) and to minor amounts of yeast glycolytic enzymes. No intact hordeins were detected, although fragments derived from γ₃- and B-hordein were present. In consideration of the many implications of the protein/peptide pattern, these data provide useful information to improve quality and safety of beer.     

Experimental Determination of the Boiling Heat Transfer Coefficients of R-134a and R-417A on a Smooth Copper Tube

Flooded evaporators are widely used as compact cooling units to cool liquids. They consist of a shell-and-tube heat exchanger, with the fluid to cool flowing inside the tubes of the bundle and a refrigerant that evaporates over those tubes. Pool boiling on the external surface of the tubes is a very complex process, and therefore the boiling heat transfer coefficients (HTCs) should be determined experimentally. Copper and copper alloys tubes are commonly employed in such heat exchangers, due to their high thermal conductivity and relative low cost. On the other hand, refrigeration and air conditioning sectors are undergoing significant changes caused mainly by the necessity of replacing existing refrigerants with more environmentally friendly ones. This paper reports the experimental determination of the pool boiling HTCs of R-134a and R-417A blend on a smooth copper tube of 18.87 mm diameter, at two saturation temperatures of 10°C and 7°C. Although smooth tubes are not commonly used in shell-and-tube evaporators nowadays, it is a first approach to pool boiling of drop-in refrigerants. The experimental setup and data acquisition are described, the experimental procedure is explained, the data reduction methodology is detailed, and the results are presented and discussed.     

Production of ultrapure hydrogen in a Pd–Ag membrane reactor using noble metals supported on La–Si oxides. Heterogeneous modeling for the water gas shift reaction

Two different catalysts, Rh(0.6% wt/wt)/La₂O₃(27% wt/wt)·SiO₂ and Pt(0.6% wt/wt)/La₂O₃(27%)·SiO₂, were tested in the WGS reaction. Their performances were first studied in a conventional fixed-bed reactor. Their activities were similar and they were both very stable. However, as Pt(0.6)/La₂O₃(27)·SiO₂ showed a much higher selectivity to the desired reaction, the performance of a membrane reactor employing this catalyst was studied. The effects of the H₂O/CO ratio, space velocity, sweep gas flow rate and size of the catalyst particle on CO conversion and H₂ recovery were studied at laboratory scale under isothermal conditions. A 1-D heterogeneous model was developed in order to properly reproduce the experimental results obtaining good agreement between the simulation results and laboratory data. The experimental and theoretical results confirm the existence of significant external mass-transfer limitations in the fluid-particle interface for these very active formulations.     

Influence of seed sludge and pretreatment method on hydrogen production in packed-bed anaerobic reactors

Several studies have reported on the effects of inoculums source and pretreatment on biological hydrogen production. However, there have been few studies on continuous reactors. This paper investigated the influence of different seed sludge sources and pretreatment methods on biohydrogen production in up-flow anaerobic fixed-bed reactors fed with sucrose. The following inoculum sources were included in the study: (1) anaerobic sludge from an up-flow anaerobic sludge blanket (UASB) reactor used to treat poultry slaughterhouse wastewater (Sl), (2) anaerobic sludge from a UASB reactor used to treat swine wastewater (Sw) and (3) autofermentation (A). Heat (He) and acid (Ac) shock were used to increase hydrogen production and suppress hydrogen consumption. The average hydrogen yields (HY) in the experiment were 2.1 (A), 2.0 (SlHe), 2.0 (SlAc), 1.0 (Sl), 1.0 (SwAc), 0.7 (SwHe) and 0.7 (Sw) mol H₂ mol⁻¹ sucrose. Although heat shock produced the maximum HY value (SlHe), acid pretreatment (SlAc) resulted in more stable hydrogen production with the largest average value, which could be an advantage of using pH shock. The autofermentation process presented HY values similar to those produced with SlAc and SlHe, making it a suitable seed sludge for biohydrogen production because pretreatment was not required.     

Solvent and stabilizer free growth of Ag and Pd nanoparticles using metallic salts/cyclotriphosphazenes mixtures

Cyclotriphosphazene is used as a sacrificial solid-state template to synthesize a range of Ag and Pd nanoparticles with diverse geometries by thermal treatment using MLn/N₃P₃(O₂C₁₂H₈)₃ mixtures. The Pd and Ag nanoparticles are synthesized by solid-state pyrolysis of AgPPh₃[CF₃SO₃]/N₃P₃(O₂C₁₂H₈)₃ and PdCl₂/N₃P₃(O₂C₁₂H₈)₃ mixtures with molar relationships of 1:1, 1:5 and 1:10 respectively, in air and at 800 °C. The morphology of the as-prepared nanoparticles is found to depend on the molar ratio of the precursor mixture, the preparation method and of the nature of the metal. Ag and Pd, microcrystals were thermally grown on Si from the respective 1:1 precursors while that metal foams were grown from 1:5 ratios precursors on SiO₂ wafers. High resolution transmission electron microscopy investigations reveal in most cases small crystals of Pd. HRSTEM measurements indicate that the formation of the Pd and Ag nanoparticles occurs through a phase demixing and dewetting mechanism. This approach has potential to be a useful and facile method to prepare metallic nanoparticles without requiring solutions or surfactants for application in electronic, catalytic and sensor materials and devices.     

Kiln Drying of Acacia mangium Willd Wood: Considerations of Moisture Content before and after Drying and Presence of Wet Pockets

Acacia mangium is an important plantation species cultivated in Costa Rica and other tropical countries worldwide. However, wood uses have been limited due to drying-related problems such as high initial moisture content (MC_i) and high variability in final moisture content (MC_f). The objective of this study was to investigate the causes of these problems. Climatic conditions where trees grow, tree height, grain pattern, drying schedules, distance from pith, and sapwood or heartwood presence were considered. Results showed an average MC_i of 127% ranging from 58 to 186%. MC_i variation was influenced by climatic conditions, tree height, and grain pattern. Average MC_f was 19%, ranging from 9 to 52%. Lack of MC_f uniformity after drying is influenced by tree height, drying schedule, and the interaction of both factors. Wet pockets were also found to develop during drying. Lumber from trees growing in humid tropical climates subjected to a low relative humidity drying schedule as well as rift-sawn or double rift-sawn lumber was likely to develop wet pockets.