Design of Nonionic Surfactants for Supercritical Carbon Dioxide     

JB McClain  DE Betts  DA Canelas  ET Samulski  JM DeSimone  JD Londono  HD Cochran  GD Wignall  D Chillura-Martino  R Triolo 《Science (New York, N.Y.)》1996,274(5295):2049-2052

Interfacially active block copolymer amphiphiles have been synthesized and their self-assembly into micelles in supercritical carbon dioxide (CO2) has been demonstrated with small-angle neutron scattering (SANS). These materials establish the design criteria for molecularly engineered surfactants that can stabilize and disperse otherwise insoluble matter into a CO2 continuous phase. Polystyrene-b-poly(1,1-dihydroperfluorooctyl acrylate) copolymers self-assembled into polydisperse core-shell-type micelles as a result of the disparate solubility characteristics of the different block segments in CO2. These nonionic surfactants for CO2 were shown by SANS to be capable of emulsifying up to 20 percent by weight of a CO2-insoluble hydrocarbon into CO2. This result demonstrates the efficacy of surfactant-modified CO2 in reducing the large volumes of organic and halogenated solvent waste streams released into our environment by solvent-intensive manufacturing and process industries.  相似文献   

Proliferating cells express mRNAs with shortened 3' untranslated regions and fewer microRNA target sites     

Sandberg R  Neilson JR  Sarma A  Sharp PA  Burge CB 《Science (New York, N.Y.)》2008,320(5883):1643-1647

Messenger RNA (mRNA) stability, localization, and translation are largely determined by sequences in the 3' untranslated region (3'UTR). We found a conserved increase in expression of mRNAs terminating at upstream polyadenylation sites after activation of primary murine CD4+ T lymphocytes. This program, resulting in shorter 3'UTRs, is a characteristic of gene expression during immune cell activation and correlates with proliferation across diverse cell types and tissues. Forced expression of full-length 3'UTRs conferred reduced protein expression. In some cases the reduction in protein expression could be reversed by deletion of predicted microRNA target sites in the variably included region. Our data indicate that gene expression is coordinately regulated, such that states of increased proliferation are associated with widespread reductions in the 3'UTR-based regulatory capacity of mRNAs.  相似文献   

The predicted impact of possible climatic change on virus-vector nematodes in Great Britain     

R. Neilson  B. Boag 《European journal of plant pathology / European Foundation for Plant Pathology》1996,102(2):193-199

Data extracted from surveys of plant-parasitic nematodes in Great Britain allowed relatively detailed maps of the geographical distribution of various longidorid and trichodorid virus-vector nematode species to be produced. These distributions are related to long-term monthly mean temperature. Recently published figures for climate change were applied to the distribution data. A potential increase in nematode associated problems due to climate change using examples of existing published data are examined and discussed.  相似文献   

动物基因转移技术     

J.D.Murray  聂进宝 《中国畜牧兽医》1989,16(4):8-10

Grodon首先于1980年报道,转移克隆化的外源DNA到小鼠体中,而使小鼠的所有细胞都含有外源基因。随后又有很多类似报道,被整合的外源基因,即转基因被稳定地整合到转基因动物的基因组中,并按孟德尔方式遗传。然而,转基因动物内在的潜力却首先是由Palmiter等(1982)证明的。他们发现,当转移到小鼠体内的生长激素基因表达时,明显增加了生长速度。近十年来,转基因小鼠通常都用做研究工具,很多实验室试图应用这一技术来改变家畜的基因型。到本世纪末或下世纪  相似文献   

Meeting food safety challenges     

JD TULLOCH 《Australian veterinary journal》1997,75(11):800-801

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Polyarthritis in wild mice (Mus musculus) caused by Streptobacillus moniliformis     

JD TAYLOR  CP STEPHENS  RG DUNCAN†  GR SINGLETON† 《Australian veterinary journal》1994,71(5):143-145

SUMMARY Mice trapped on farms in south-eastern Queensland had chronic abscessating osteoarthritides mainly involving the carpi and tarsi. Pleomorphic bacteria were shown by silver staining to be plentiful within lesions. Streptobacillus moniliformis was isolated from the joints, and streptobacillary polyarthritis was diagnosed. Other lesions observed included subcutaneous and hepatic abscesses.  相似文献   

New techniques for measuring the growth and survival of larvae of Lucilia cuprina on sheep     

CH EISEMANN  LAY JOHNSTON  JD KERR † 《Australian veterinary journal》1989,66(6):187-189

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Erysipelothrix rhusiopathiae infection of guinea fowl (Numida meleagris)     

GW CAMPBELL  JD TAYLOR  BJ HARROWER 《Australian veterinary journal》1992,69(1):13-13

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Roles of grape thaumatin-like protein and chitinase in white wine haze formation     

Marangon M  Van Sluyter SC  Neilson KA  Chan C  Haynes PA  Waters EJ  Falconer RJ 《Journal of agricultural and food chemistry》2011,59(2):733-740

Grape chitinase was found to be the primary cause of heat-induced haze formation in white wines. Chitinase was the dominant protein in a haze induced by treating Sauvignon blanc wine at 30 °C for 22 h. In artificial wines and real wines, chitinase concentration was directly correlated to the turbidity of heat-induced haze formation (50 °C for 3 h). Sulfate was confirmed to have a role in haze formation, likely by converting soluble aggregates into larger visible haze particles. Thaumatin-like protein was detected in the insoluble fraction by SDS-PAGE analysis but had no measurable impact on turbidity. Differential scanning calorimetry demonstrated that the complex mixture of molecules in wine plays a role in thermal instability of wine proteins and contributes additional complexity to the wine haze phenomenon.  相似文献   

The Impact of Solar Variability on Climate   总被引：5，自引：0，他引：5  

JD Haigh 《Science (New York, N.Y.)》1996,272(5264):981-984

A general circulation model that simulated changes in solar irradiance and stratospheric ozone was used to investigate the response of the atmosphere to the 11-year solar activity cycle. At solar maximum, a warming of the summer stratosphere was found to strengthen easterly winds, which penetrated into the equatorial upper troposphere, causing poleward shifts in the positions of the subtropical westerly jets, broadening of the tropical Hadley circulations, and poleward shifts of the storm tracks. These effects are similar to, although generally smaller in magnitude than, those observed in nature. A simulation in which only solar irradiance was changed showed a much weaker response.  相似文献