The effect of inorganic additives on the formation,composition, and combustion of cellulosic char

At temperature above 300°C the glycosyl units of cellulose are simultaneously depolymerized to a tar and decomposed to a char by evolution of H₂O, CO, and CO₂. When the glycosyl units are depleted, a stable char is formed containing about 30% aliphatic and 70% aromatic components. The aliphatic component is formed first, but on further heating is converted to polycyclic aromatic structures. The chars formed at lower temperatures are more combustible because the aliphatic component of the char is highly pyrophoric and is oxidized almost at the same temperature at which it is formed (～360°C). The aromatic component, however, is less reactive and is oxidized at ～520°C. Consequently, the chars formed at higher temperatures are less combustible. It has been shown that (NH₄)₂HPO₄, which is a well-known flame retardant and smoldering inhibitor, lowers the pyrolysis temperature and increases the char yield by accelerating the decomposition reactions. This affects the composition of the intermediate chars but the final products have about the same composition irrespective of additives. (NH₄)₂HPO₄ also lowers the rate of oxidation of the aromatic component and the corresponding heat release. NaCl, which is an enhancer of smoldering combustion, has a slight stabilizing effect on pyrolysis of cellulose. It lowers the oxidation temperature of the aromatic component and dramatically increases its rate. The corresponding heat release is also increased due to complete oxidation to CO₂. The rate of oxidation calculated from the dynamic thermal analysis data is more than tripled by NaCl and significantly reduced by (NH₄)₂HPO₄.     

The distribution of serum high density lipoprotein subfractions in non-human primates

The ultracentrifugal flotation patterns in 1.2 g/ml solvent and ultracentrifugal gradient distribution of high density lipoproteins (HDL) from the primates-human, apes and monkeys-were determined, with emphasis on the gorilla species of apes and rhesus monkeys. Diets for non-human primates were commercial chow, which is low in cholesterol. Molecular weights and protein, cholesterol, phospholipid and triglyceride compositions of various density fractions were determined on human, gorilla and rhesus HDL. The HDL₂/HDL₃ ratio was determined from the two peaks observed upon flotation in high salt in the analytical ultracentrifuge. The HDL₂ of all three species of apes-gorillas (Gorilla gorilla), chimpanzees (Pan troglodytes) and orangutans (Pongo pygmaeus)—was always greater than HDL₃, while that of all six species of Old World monkeys-Rhesus (Macaca mulatta), sooty mangabeys (Cercocebus atys), cynomolgus (Macaca fascicularis), stumptails, (Macaca arctoides) patas (Erythrocebus patas) and African greens (Cercopithecus aethiops)—was less. In addition, the HDL₃ concentration in five gorillas was about 15 mg/dl as cholesterol while the HDL₂ concentration was 92 mg/dl, much lower and higher, respectively, than humans. HDL₂ of gorillas was similar in density and molecular weight to that of humans. The distribution of densities in gorilla HDL was predominantly in HDL₂, while rhesus HDL usually, but not always, was unimodal, having a density distribution similar in heterogeneity to human HDL₃, but somewhat less dense (peaking at 1.109 vs 1.129 g/ml). The molecular weight of rhesus HDL was about the same as human HDL₃ in all three density subfractions and at the peak density. Likewise, the chemical compositions were similar for the subfractions 1.10–1.125 and>1.125 g/ml for rhesus HDL and human HDL₃. Consequently most but not all chow-fed rhesus HDL was very similar to human HDL₃, but lighter in density. A preliminary report of this study was given at the American Society for Biological Chemists Meeting in New Oreleans in April 1982.     

Proximate Composition and Seed Lipid Components of Sorghum Cultivars from Argentina

Seeds of 11 sorghum cultivars ( Sorghum bicolor ) from Argentina were analysed for proximate composition, fatty acids and sterols. Oil, protein, carbohydrate and ash contents varied between 41 and 66 g kg⁻¹, 111 and 156 g kg⁻¹, 670 and 730 g kg⁻¹ and 13·8 and 20·6 g kg⁻¹ of dry matter, respectively. Fatty acid profiles revealed that the major acids were palmitic (15·1–24·8%), oleic (29·9–41·8%) and linoleic (35·9–51·3%). Unsaponifiable matter was examined for sterols. Sitosterol was the prominent component in all cultivars (43·8–57·9%), followed by campesterol (18·7–29·1%) and stigmasterol (12·4–20·5%).     

Quantification of ethyl carbamate in cachaça produced in different agro‐industrial production systems

Popularly known by various names such as caninha, dangerous, drips, damned and many other denominations, cachaça is the genuine Brazilian drink, produced by the fermentation of sugarcane juice by yeast, followed by distillation in alambics. Considering that cachaça is the most widely consumed distilled beverage from Brazil, the knowledge of the chemical composition and the presence of potentially toxic compounds such as ethyl carbamate, considered a human carcinogen, is important. The aim of this study was to evaluate the influence of different conditions of the agro‐industrial cachaça production systems, including the variety of sugarcane, on the quantification of ethyl carbamate through the chromatographic. Thirteen unaged beverage samples, produced from different varieties of sugarcane, were analysed. Using analysis of variance and comparison of average concentrations of ethyl carbamate (Scott–Knott, α = 5%), all of the samples were found to contain contaminant levels below the ceiling established by the legislation, which is 210 µg L^?1. Copyright © 2016 The Institute of Brewing & Distilling     

Milk yield and somatic cell count during the following lactation after selective treatment of cows at dry-off

Selective dry cow therapy (SDCT) has received increasing attention in recent years owing to global concerns over agricultural use of antimicrobial drugs and development of antimicrobial resistance. The objective of this study was to evaluate the effect of SDCT on milk yield and somatic cell count (SCC) in dairy herds in the USA. Cows in four Ohio dairy herds were categorized into two groups (low-SCC and high-SCC) at dry-off based on their SCC and clinical mastitis (CM) history during the lactation preceding the dry-off. Low-SCC cows were randomly assigned to receive or not to receive intramammary antibiotics at dry-off. Milk yield and SCC of these cows during the following lactation were compared using linear mixed effects models, adjusting for parity, calving season, stage of lactation, previous lactation milk yield and herd. Milk yield of untreated and treated low-SCC cows at dry-off did not differ significantly during the following lactation. Overall, treated low-SCC cows had 16% lower SCC (approximately 35 000 cells/ml, P = 0·0267) than the untreated cows during the following lactation; however, the effect was variable in different herds. Moreover the impact of treatment, or the lack thereof, on milk yield varied considerably between herds. The results suggested that in some herds treating all cows at dry-off may be beneficial while in other herds leaving healthy cows without antibiotic dry cow treatment has no negative impact on milk yield or milk quality (SCC), and in fact, may be beneficial. Further studies are needed to identify characteristics of herds where treating all cows routinely at dry-off may be needed for maintaining good udder health and where switching to selective treatment of cows at dry-off would be the optimal approach to achieve best results.     

Effect of temperature and water availability during late maturation of the soybean seed on germ and cotyledon isoflavone content and composition

BACKGROUND: Isoflavone content in soybean seeds is strongly influenced by both environment and genotype. However, little is known about the effect of environment and genotype on isoflavones in germ versus cotyledons. To determine the effect of temperature and soil moisture status during soybean seed development on seed isoflavone concentration and composition, a set of two French and three US cultivars of similar maturity were grown in the greenhouse. At the R6 growth stage, plants were subjected to one of three night/day temperature regimes (13/23°, 18/28° or 23/33 °C) in either optimal or sub‐optimal soil water conditions. RESULTS: In cotyledons, a three‐ to six‐fold variation in total isoflavone content was observed between the high and low temperature treatments, whereas the germ contents had less than a two‐fold variation. Soil water supply had less effect than temperature on the isoflavone contents and compositions. In both seed parts, the isoflavone concentrations were highly dependent on the cultivar. CONCLUSION: These results show that isoflavone content and composition in cotyledon and germ are unrelated and it should be possible to independently manipulate these seed traits through plant breeding and crop management systems. Copyright © 2007 Society of Chemical Industry     

Disentangling oil weathering at a marine seep using GC x GC: broad metabolic specificity accompanies subsurface petroleum biodegradation

Natural seeps contribute nearly half of the oil entering the coastal ocean. However, environmental fate studies generally monitor fewer than 5% of these petroleum compounds. Hence, the rates and relevance of physical, chemical, and biological weathering processes are unknown for the large majority of hydrocarbons, both released from natural seeps and also from human activities. To investigate the specific compositional changes occurring in petroleum during subsurface degradation and submarine seepage, we studied the natural oil seeps offshore Santa Barbara, California with comprehensive, two-dimensional gas chromatography (GC x GC). With this technique, we quantified changes in the molecular diversity and abundance of hydrocarbons between subsurface reservoirs, a proximal sea floor seep, and the sea surface overlying the seep. We also developed methods to apportion hydrocarbon mass losses due to biodegradation, dissolution, and evaporation, for hundreds of tracked compounds that ascended from the subsurface to the sea floor to the sea surface. The results provide the first quantitative evidence of broad metabolic specificity for anaerobic hydrocarbon degradation in the subsurface and reveal new trends of rapid hydrocarbon evaporation at the sea surface. This study establishes GC x GC as a powerful technique for differentiating biological and physical weathering processes of complex mixtures at a molecular level.     

NO and NO2 emission ratios measured from in-use commercial aircraft during taxi and takeoff

In August 2001, the Aerodyne Mobile Laboratory simultaneously measured NO, NO2, and CO2 within 350 m of a taxiway and 550 m of a runway at John F. Kennedy Airport. The meteorological conditions were such that taxi and takeoff plumes from individual aircraft were clearly resolved against background levels. NO and NO2 concentrations were measured with 1 s time resolution using a dual tunable infrared laser differential absorption spectroscopy instrument, utilizing an astigmatic multipass Herriott cell. The CO2 measurements were also obtained at 1 s time resolution using a commercial non-dispersive infrared absorption instrument. Plumes were measured from over 30 individual planes, ranging from turbo props to jumbo jets. NOx emission indices were determined by examining the correlation between NOx (NO + NO2) and CO2 during the plume measurements. Several aircraft tail numbers were unambiguously identified, allowing those specific airframe/engine combinations to be determined. The resulting NOx emission indices from positively identified in-service operating airplanes are compared with the published International Civil Aviation Organization engine certification test database collected on new engines in certification test cells.     

Effects of monoglyceride content,cooling rate and shear on the rheological properties of olive oil/monoglyceride gel networks

Functionality of conventional fat spreads can be achieved without hydrogenation by the formation of stable network structures upon cooling of mixtures of monoglycerides (MGs) and vegetable oils from the melt. Such mixtures are healthy substitutes for margarine and butter. The effects of MG content, cooling rate and shear on the temperature ramp, mechanical spectra and hardness of olive oil/MG gel networks were investigated. A minimum MG volume fraction was necessary for formation of a gelled network, but this concentration was less than that needed for a space‐filling network structure. Onset of gel network or structure formation was indicated by a sudden divergence in value of the elastic modulus G′. The temperature at onset of structure formation, T_o, final G′ value and network hardness all increased with increase in MG content. High cooling rates led to low final G′ values but harder networks, and vice versa. Maximum gel network development occurred when moderate shear (about 300 s^?1) was applied at incipient gelation. Copyright © 2004 Society of Chemical Industry