Micro- and nanostructured poly[oligo(ethylene glycol)methacrylate] brushes grown from photopatterned halogen initiators by atom transfer radical polymerization

Photolithographic techniques have been used to fabricate polymer brush micro- and nanostructures. On exposure to UV light with a wavelength of 244 nm, halogens were selectively removed from films of chloromethylphenyltrichlorosilane and 3-(2-bromoisobutyramido)propyl-triethoxysilane on silicon dioxide. Patterning was achieved at the micrometer scale, by using a mask in conjunction with the incident laser beam, and at the nanometer scale, by utilizing interferometric lithography (IL). Friction force microscopy images of patterned surfaces exhibited frictional contrast due to removal of the halogen but no topographical contrast. In both cases the halogenated surface was used as an initiator for surface atom-transfer radical polymerization. Patterning of the surface by UV lithography enabled the definition of patterns of initiator from which micro- and nanostructured poly[oligo(ethylene glycol)methacrylate] bottle brushes were grown. Micropatterned brushes formed on both surfaces exhibited excellent resistance to protein adsorption, enabling the formation of protein patterns. Using IL, brush structures were formed that covered macroscopic areas (approximately 0.5 cm2) but exhibited a full width at half maximum height as small as 78 nm, with a period of 225 nm. Spatially selective photolytic removal of halogens that are immobilized on a surface thus appears to be a simple, rapid, and versatile method for the formation of micro- and nanostructured polymer brushes and for the control of protein adsorption.     

山西省棉区棉花促早熟集成避霜技术研究

试验研究棉花促早熟集成避霜技术结果表明 ,喷施壮早丰后棉花生育进程加快 ,吐絮期提早 2～ 4d ,单株铃数和铃重增加 ,皮棉比对照增产 12 2 3% ,且对棉花纤维品质无不良影响。并提出以壮早丰系统化学调控、地膜覆盖和增加棉花种植密度为关键技术 ,配合适期播种、选择早熟品种、水肥运筹、病虫害综合防治和乙烯利催熟等棉花系统促早熟集成避霜配套栽培技术措施 ,皮棉可增产 14 34%～ 2 4 5 8%。     

Studies on Persian clover (Trifolium resupinatum)

Yields of green fodder, dry matter and nitrogen were adversely affected by an increase in the harvesting interval of Persian clover from 40 to 100 days. The optimum harvesting interval which gave maximum yield of green fodder (86.6 ton/ha) and dry matter (11.2 ton/ha) was 30 days. The maximum yield of total nitrogen (423 kg/ha) was obtained when the harvesting interval was 20 days.     

Extraction of oil from Jatropha curcas L. seed kernels by enzyme assisted three phase partitioning

Three phase partitioning has been evaluated for extraction of oil from Jatropha curcas L. seeds. This process consisted of simultaneous addition of t-butanol (1:1, v/v) and 30% (w/v) ammonium sulphate to the slurry prepared from Jatropha seed kernels. Combination of sonication and enzyme treatment with a commercial preparation of fungal proteases at pH 9, led to 97% oil yield within 2 h.     

Biochemical changes in wheat during storage at three temperatures

Biochemical changes in wheat grains stored at 10, 25 and 45 °C for six months were studied. A significant decrease in pH and an increase in titratable acidity was observed during storage of wheat grains at 25 °C and 45 °C. Moisture contents of wheat grains decreased by 15% at 25 °C and 26% at 45 °C during six months of storage. A significant decrease in water soluble amylose (20–28%) along with an increase in insoluble amylose contents (7.6–17%) were observed during storage at 25 and 45 °C. Amylase activity of the samples showed a decrease as the storage progressed. Total soluble sugars increased by 9% at 10 °C and 12% at 25 °C; a 37% decrease was observed after six months storage at 45 °C. Total available lysine decreased by 18.0% and 22.6% at 25 and 45 °C, respectively, after six months storage. In vitro protein digestibility of wheat grains decreased by 5.00% at 25 °C and 10.28% at 45 °C during six months of storage. However, no significant biochemical changes occurred during storage at 10 °C.     

Growth,blood chemistry and histology of rats fed zincsupplemented rapeseed protein concentrates

Two rapeseed protein concentrates (RPC) supplemented with zinc oxide were fed to male and female rats at two levels providing approximately half or all of the protein in a purified basal diet containing 20% protein (N×6.25). Control groups were given either a purified basal diet with casein or a laboratory chow diet. After 16 weeks, there were no significant (P<0.05) differences in body weight except the male rats fed the casein control diet had higher body weights than did other male rats. No significant differences were observed in organ weights including thyroids, hematology, bone marrow differential counts, serum glucose, urea nitrogen, total protein, albumin/globulin ratio, cholesterol, transaminases or alkaline phosphatase. The levels of serum vitamins A and E of females fed some of the RPC diets were less than in those fed the caseincontrol diet, but equal to those in females fed laboratory chow diet. Females fed either RPC or casein in the semi-purified diets, which contained zinc oxide, exhibited kidney calcification.Bureau of Nutritional Sciences, No. 112; Food Research Institute, No. 420.     

Plant density and nitrogen effects on growth dynamics,light interception and yield of maize

Maize (Zea mays L.) growth and yield are most sensitive to variations in plant density and nitrogen (N) in north-western Pakistan. This study was conducted on the Agricultural Research Farm of NWFP (North West Frontier Province) Agricultural University, Peshawar, from 2002–2004 to establish an accurate plant density and N management system aimed at high yield of maize. The 2 × 3 × 6 factorial experiment was designed having two plant densities (P1 = 60,000 and P2 = 100,000 plants ha^?1) and three nitrogen rates (N1 = 60, N2 = 120 and N3 = 180 kg N ha^?1) applied to the main plots, while six split application for N in different proportions were applied to subplots at different growth stages of maize in two equal (S1), three equal (S2), three unequal (S3), four equal (S4), five equal (S5) and five unequal splits (S6) at sowing and with 1st, 2nd, 3rd and 4th irrigation at two-week intervals. Growth rate and yield increased with elevated dose and number of N split applications. Improved endurance to high stands allowed maize to intercept and use solar radiation more efficiently, contributing to the remarkable increase in the crop growth rate and yield.     

Buffalo (Bubalus bubalis) ES Cell–Like Cells are Capable of In Vitro Skeletal Myogenic Differentiation

When buffalo embryonic stem (ES) cell–like cells that expressed surface markers SSEA‐4, TRA‐1‐60, TRA‐1‐81, CD9 and CD90 and intracellular markers OCT4, SOX2 and FOXD3, as shown by immunofluorescence, and that expressed REX‐1 and NUCLEOSTEMIN as confirmed by RT‐PCR, were subjected to suspension culture in hanging drops in absence of LIF and buffalo foetal fibroblast feeder layer support, they differentiated to form three‐dimensional embryoid bodies (EBs). Of 231 EBs examined on Day 3 of suspension culture, 141 (61.3 ± 3.09%) were of compact type, whereas 90 (38.4 ± 3.12%) were of cystic type. The cells obtained from EBs were found to express NF‐68 and NESTIN (ectodermal lineage), BMP‐4 and α‐skeletal actin (mesodermal lineage), and α‐fetoprotein, GATA‐4 and HNF‐4 (endodermal lineage). When these EBs were cultured on gelatin‐coated dishes, they spontaneously differentiated to several cell types such as epithelial‐ and neuron‐like cells. When EBs were cultured in the presence of 1 or 2% DMSO or 10^?8 m or 10^?7 m retinoic acid for 25 days, ES cells could be directed to form muscle cell–like cells, the identity of which was confirmed by expression of α‐actinin by immunofluorescence and of MYF‐5, MYOD and MYOGENIN genes by RT‐PCR. MYOD was first detected on Day 10 in both treatment groups and on Day 15 in controls, whereas MYOGENIN was first detected on Day 10, Day 15 and Day 25 in the presence of retinoic acid, in the presence of DMSO and in controls, respectively. The present study demonstrates the ability of buffalo ES cell–like cells to undergo directed differentiation to cells of skeletal myogenic lineage.     

Development of Heat Tolerant Two-Line Hybrid Rice Restorer Line Carrying Dominant Locus of OsHTAS

In order to create novel germplasm resources for breeding heat tolerant variety,we transferred a dominant allele OsHTAS,previously characterized and cloned from a high-temperature tolerant local variety HT54,which was collected from the rice production area of southern China,into a high-temperature sensitive intermediate breeding line HT13 through six rounds of successive backcross by using marker-assisted selection.The molecular analysis showed that the recovery of genetic background of a resultant near isogenic line(NIL),MHT13,was around 99.8%.The OsHTAS gene introduced in the MHT13 expressed normally in the HT13 genetic background,mediating heat tolerance and phenotype similar to those of the donor parent HT54.The major agronomic traits of MHT13 resembled those of the recurrent parent HT13.Moreover,MHT13 had high general combining ability and its rice quality reached the grade 3 standard of edible high-quality rice issued by Ministry of Agriculture of the People’s Republic of China,which greatly improved its application value in rice production.     

发动机悬置系统的研究综述

发动机悬置系统的动静态特性影响整车的行驶平顺性,因此对发动机动力总成的研究可以在一定程度上改善乘车的舒适性和行驶的平顺性;同时合理地选择动力总成悬置参数有利于降低发动机的振动向车架的传递,改善汽车的NVH性能。本论文对汽车动力总成研究的方法和理论做出了详细的论述,并对悬置元件的发展作了扼要说明,为发动机悬置系统的研究提供了完善的理论参考。