碱法草浆洗涤性质的多段模拟研究

由于草浆中含有大量的硅、半纤维素和杂细胞,碱法草浆的黑液粘度较大。与硫酸盐木浆比较,麦草浆在多段洗涤过程中耗水量大,滤水性能和洗涤效率低。本文主要研究了麦草浆的洗涤性质以及硫酸盐木浆和非木材碱法浆的实验室模拟洗涤过程。结果表明:洗涤效率取决于洗涤水和浆悬浮液中黑液的浓度差别。

肥皂的洗涤性质、效果和生物降解性

合成表面活性剂脂肪醇硫酸盐是最早作为洗涤剂的表面活性剂。脂肪醇硫酸盐最初是在1932年使用于高级洗涤剂Fewa中。脂肪醇硫酸盐是通过脂肪酸高压氢化与所得脂肪醇硫酸化制得的。从1935到1945年以煤和石油为原料合成得到了其他的表面活性化合物,此与战争时期居民的脂肪供给也有关。IG染料工业公司的Scholler和Wittwer在1930年的进一步发明是一项重要的发明,他们用环氧乙烷生产非离子表面活性剂。当时开发的表面活性剂、脂肪醇硫酸盐、烷基磺酸盐。

Leaf choice in black-and-white snub-nosed monkeys Rhinopithecus bieti is related to the physical and chemical properties of leaves

To understand the effects of the chemical and physical properties of plant leaves on food choice in Rhinopithecus bieti, we collected mature leaves of nine food and five non-food plant species at the southernmost part of the species＇s range. Chemical properties such as fat, ash, crude protein （CP）, total phenolics （TP）, and fiber content including neutral detergent fiber （NDF）, acid detergent fiber （ADF）, lignin, celluloses and hemicelluloses, and physical toughness were measured. R. bieti tended to choose leaves with lower fiber content, higher ash, a higher ratio of CP/ADF, and lower toughness. No difference was found for fat, crude protein, total phenolics, hemicelluloses and lignin between food and non-food leaves. Even though the ratio of CP/ADF is generally regarded as a good indicator for colobine food choice, the difference in the ratio of CP/ADF between food and non-food leaves was only the result of differences in ADE Since positive correlations were found between ADF and tough- ness from all leaves （both food and non-food species）, and toughness of leaves was likely easier for R. bieti to sense than fiber content via mastication, the toughness of leaves may function as a predictor of food choice in this species [Current Zoology 56 （6） 643-49, 2010].

Native Trees Forage Alternative Protein Feed for Cattle in Tropical ＂Mexico＂

The objective of this study was to find highly nutritious native plants to feed cattle in northern Veracruz （Mexico） as an alternative to avoid deforestation for pasture establishment. Six fodder tree species （Leucaena, Leucaenaleucocephala, Morera, Morus alba, Chacloco, rubiHamelia patents, Guficima, Guasumaulmifolia, Pichoco-bunting, Erythrinaamericana, Cocuite, Gliricidiasepium） were selected for their leave production, rapid growth and high nutritional quality. The plants were evaluated in the bud stage of senescence and flowering, restricting the fraction of mature foliage in the samples located under 2 meters height. Samples were collected from five plants per specie that were randomly selected. The nutritious parameters were evaluated through proximate analysis with the Van Soest technique. This study used a completely randomized design with five replicates. The nutritious composition showed PC （protein content） differences （P 〈 0.05） among species indicating that Leucaenaleucocephala （20%） had the lowest, Gliricidiasepium was （21%） intermediate and Morus alba （23%） had the highest. The FDN （neutral detergent fiber） and FDA （acid detergent） were lowest for Guasumaulmifolia （23.4%） and the other five species exceeded 40%. In conclusion, native foliage of fodder trees in northern, Veracruz are highly nutritious for cattle feeding and could alternative to avoid deforestation for pasture establishment to continue.

Intake and Digestibility of Native and Exotic Grasses Fed Ad libitum to Djallonke Sheep in South Benin

Native （Andropogon gayanus, Panicum maximum and Pennisetum purpureum） and exotic grasses （Brachiaria ruzi：iensis, Panieum maximum cv. C1 and T58） consumed in tropical humid zone were evaluated by estimating their voluntary intake and in vivo digestibility. The measurements were performed with 4 male Djallonke sheep （28 kg LW） fed ad libitum in metabolic cages, during a 10-days in vivo trial, preceded by a 14-days accommodation period. Each grass was studied at 3 stages of development. The samples （distributed grasses, refusals and faeces） were analysed for organic matter （OM）, crude fibre （CF）, neutral detergent fibre （NDF）, acid detergent fibre （ADF）, acid detergent lignin （ADL） and crude protein （CP） contents. Voluntary digestible organic matter intake （VDOMI） and voluntary digestible crude protein intake （VDCPI） were calculated （in g kg ^-1 LW075） as synthetic parameters to compare the grasses. The chemical composition of the distributed forages varied significantly （P 〈 0.001） between species or cultivars and development stages. After 4-5 leaves per tiller stage, CP contents decreased in all species and lowest in native species. Andropogon gayanus was the most l ignified species at any stage of development. At the end of the rainy season, Pennisetum purpureum leaves and Brachiaria ruziziensis had the highest CP. For all the grasses, CP contents were higher （and CF contents lower） in the consumed material, compared to the offered forages, showing thereby the high selectivity by the sheep. Dry matter intake, OM and CP digestibility varied greatly （P 〈 0.001） between forages and development stages with high interactions between these factors （P 〈 0.001）. Voluntary digestible organic matter intake and VDCPI were the highest （P 〈 0.05） for native Panicum maximum and Pennisetum purpureum. There was a relationship between digestibility and intake parameters, and ADL content of the grasses seems to be an important factor determining at least digestibility.

Nutritional Value Evaluation of Saccharum spontaneum L. Germplasm Resources

The contents of dry matter, crude fat, crude protein, neutral detergent fiber, acid detergent fiber, crude ash, Ca and P in 43 Saccharum spontaneum L.germplasms during the vegetative period were determined. Among them, the crude protein, crude fat, neutral detergent fiber, acid detergent fiber, P and Ca contents were treated as the judging indicators. The nutritional value evaluation was carried out with the analytic hierarchy process(AHP). The results showed A49(Guangxi)had the highest nutritional value. Its dry matter, crude protein, crude fat, crude ash,neutral detergent fiber, acid detergent fiber, Ca and P contents were 32.35%,7.20%, 4.06%, 8.07%, 75.81%, 50.72%, 0.23% and 0.16% respectively. While A3(Guangdong) had the lowest nutritional value. Its dry matter, crude protein, crude fat, crude ash, neutral detergent fiber, acid detergent fiber, Ca and P contents were32.24%, 4.62%, 0.51%, 6.38%, 46.40%, 40.02%, 0.15% and 0.09% respectively.The crude protein content differed significantly among different germplasms. A48 had the highest crude protein content(9.11%), and A14 had the lowest crude protein content(3.72%). Based on the evaluation results, the 43 Saccharum spontaneum L.germplasms were divided into 3 groups: high-nutritional value type, moderate-nutritional value type and low-nutritional value type. We hoped to provide a theoretical reference for the application of Saccharum spontaneum L. as a forage grass.

Structural analysis of a nanoparticle containing a lipid bilayer used for detergent-free extraction of membrane proteins

In the past few years there has been a growth in the use of nanoparticles for stabilizing lipid membranes that contain embedded proteins. These bionanoparticles provide a solution to the challenging problem of membrane protein isolation by maintaining a lipid bilayer essential to protein integrity and activity. We have previously described the use of an amphipathic polymer （poly（styrene-co-maleic add）, SMA） to produce discoidal nanoparticles with a lipid bilayer core containing the embedded protein. However the structure of the nanoparticle itself has not yet been determined. This leaves a major gap in understanding how the SMA stabilizes the encapsulated bilayer and how the bilayer relates physically and structurally to an unencapsulated lipid bilayer. In this paper we address this issue by describing the structure of the SMA lipid particle （SMALP） using data from small angle neutron scattering （SANS）, electron microscopy （EM）, attenuated total reflection Fourier transform infrared spectroscopy （ATR-FTIR）, differential scanning calorimetry （DSC） and nuclear magnetic resonance spectroscopy （NMR）. We show that the particle is disc shaped containing a polymer ＂bracelet＂ encircling the lipid bilayer. The structure and orientation of the individual components within the bilayer and polymer are determined showing that styrene moieties within SMA intercalate between the lipid acyl chains. The dimensions of the encapsulated bilayer are also determined and match those measured for a natural membrane. Taken together, the description of the structure of the SMALP forms the foundation for future development and applications of SMALPs in membrane protein production and analysis.