Radar soundings of the subsurface of Mars   总被引：2，自引：0，他引：2  

Picardi G  Plaut JJ  Biccari D  Bombaci O  Calabrese D  Cartacci M  Cicchetti A  Clifford SM  Edenhofer P  Farrell WM  Federico C  Frigeri A  Gurnett DA  Hagfors T  Heggy E  Herique A  Huff RL  Ivanov AB  Johnson WT  Jordan RL  Kirchner DL  Kofman W  Leuschen CJ  Nielsen E  Orosei R  Pettinelli E  Phillips RJ  Plettemeier D  Safaeinili A  Seu R  Stofan ER  Vannaroni G  Watters TR  Zampolini E 《Science (New York, N.Y.)》2005,310(5756):1925-1928

The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.  相似文献   

MET amplification leads to gefitinib resistance in lung cancer by activating ERBB3 signaling     

Engelman JA  Zejnullahu K  Mitsudomi T  Song Y  Hyland C  Park JO  Lindeman N  Gale CM  Zhao X  Christensen J  Kosaka T  Holmes AJ  Rogers AM  Cappuzzo F  Mok T  Lee C  Johnson BE  Cantley LC  Jänne PA 《Science (New York, N.Y.)》2007,316(5827):1039-1043

The epidermal growth factor receptor (EGFR) kinase inhibitors gefitinib and erlotinib are effective treatments for lung cancers with EGFR activating mutations, but these tumors invariably develop drug resistance. Here, we describe a gefitinib-sensitive lung cancer cell line that developed resistance to gefitinib as a result of focal amplification of the MET proto-oncogene. inhibition of MET signaling in these cells restored their sensitivity to gefitinib. MET amplification was detected in 4 of 18 (22%) lung cancer specimens that had developed resistance to gefitinib or erlotinib. We find that amplification of MET causes gefitinib resistance by driving ERBB3 (HER3)-dependent activation of PI3K, a pathway thought to be specific to EGFR/ERBB family receptors. Thus, we propose that MET amplification may promote drug resistance in other ERBB-driven cancers as well.  相似文献   

Predicting a human gut microbiota's response to diet in gnotobiotic mice     

Faith JJ  McNulty NP  Rey FE  Gordon JI 《Science (New York, N.Y.)》2011,333(6038):101-104

The interrelationships between our diets and the structure and operations of our gut microbial communities are poorly understood. A model community of 10 sequenced human gut bacteria was introduced into gnotobiotic mice, and changes in species abundance and microbial gene expression were measured in response to randomized perturbations of four defined ingredients in the host diet. From the responses, we developed a statistical model that predicted over 60% of the variation in species abundance evoked by diet perturbations, and we were able to identify which factors in the diet best explained changes seen for each community member. The approach is generally applicable, as shown by a follow-up study involving diets containing various mixtures of pureed human baby foods.  相似文献   

Identification of serum stress biomarkers in pigs housed at different stocking densities     

Marco-Ramell A  Pato R  Peña R  Saco Y  Manteca X  Ruiz de la Torre JL  Bassols A 《Veterinary journal (London, England : 1997)》2011,190(2):e66-e71

Eight Duroc×(Landrace×Large White) male pigs housed at a stocking rate of 0.50m(2)/pig were subjected to a higher stocking rate of 0.25m(2)/pig (higher density, HD) for two 4-day periods over 26 days. Using biochemical and proteomic techniques serum and plasma samples were examined to identify potential biomarkers for monitoring stress due to HD housing. HD housed pigs showed significant differences (P<0.001) in total cholesterol and low density lipoprotein-associated cholesterol, as well as in concentrations of the pig-major acute phase protein (Pig-MAP) (P=0.002). No differences were observed in serum cortisol or other acute phase proteins such as haptoglobin, C-reactive protein or apolipoprotein A-I. HD-individuals also showed an imbalance in redox homeostasis, detected as an increase in the level of oxidized proteins measured as the total plasma carbonyl protein content (P<0.001) with a compensatory increase in the activity of the antioxidant enzyme glutathione peroxidase (P=0.012). Comparison of the serum proteome yielded a new potential stress biomarker, identified as actin by mass spectrometry. Cluster analysis of the results indicated that individuals segregated into two groups, with different response patterns, suggesting that the stress response depended on individual susceptibility.  相似文献   

Using BCG,MPT-51 and Ag85 as antigens in an indirect ELISA for the diagnosis of bovine tuberculosis     

Ediane Batista da Silva  Bruna Daniella de Souza Silva  Jerônimo Rafael Ruiz Leon  André Kipnis  Isabel K.F. de Miranda Santos  Ana Paula Junqueira-Kipnis 《Veterinary journal (London, England : 1997)》2011,187(2):276-278

This study evaluated the Mycobacterium tuberculosis protein antigen MPT-51, the trimeric antigen 85 (Ag85) complex, and Bacillus Calmette-Guérin (BCG) in an indirect ELISA to diagnose bovine tuberculosis (TB) from serum samples. Serum was collected from 208 intra-dermal tuberculin test (ITT)-positive and 54 ITT-negative animals from a region where bovine TB is endemic. Using the Ag85 and BCG antigens, the indirect ELISA was able to discriminate ITT-positive from ITT-negative animals. This level of discrimination was not achieved when using the MPT-51 antigen. The highest sensitivity (Se) and specificity (Sp) of the test was found when BCG was used (Se, 82%; Sp, 91%). Further work in different epidemiological settings and with larger numbers of animals will be required to validate these findings.  相似文献   

Higher-tier assessment of the potential for groundwater issues due to the use of 1,3-D soil fumigant; evaluation of the active ingredient, metabolites and potentially related chlorinated compounds     

Lamastra L  Ferrari F  Fait G  Greco L  Kennedy SH  Capri E  Trevisan M 《Pest management science》2011,67(11):1439-1445

BACKGROUND: 1,3‐Dichloropropene (1,3‐D, CAS No. 542‐75‐6) is a broad‐spectrum soil fumigant used to control numerous species of soilborne plant‐parasitic nematodes. 1,3‐D consists of two isomers, (Z)‐ and (E)‐1,3‐D. There are a number of low‐level chlorinated compounds that could potentially be produced as a part of the 1,3‐D manufacturing process. 1,3‐D and its metabolites, as well as potentially related chlorinated compounds, represent potential groundwater contaminants. RESULTS: This study has investigated the hydrolytic stability, under biotic and abiotic conditions in the laboratory, of an extensive representative list of 1,3‐D and potentially related chlorinated compounds in order to predict their environmental fate. All of these compounds showed intrinsic hydrolytic instability under both abiotic and biotic test conditions. Furthermore, a monitoring programme was carried out. Twenty‐five wells were monitored in five Italian regions characterised by historical and existing use of 1,3‐D. The parent compound, its two major metabolites and potentially related chlorinated compounds were not detected in the well water at > 0.1 µg L^?1 at any sampling location. CONCLUSION: The soil fumigant (E,Z)‐1,3‐D, its metabolites and potentially related chlorinated compounds constitute a low risk to groundwater. Copyright © 2011 Society of Chemical Industry  相似文献   

Chemical and biochemical properties in a silty loam soil under conventional and organic management   总被引：2，自引：0，他引：2  

Sebastiana Melero  Juan Carlos Ruiz Porras  Juan Francisco Herencia  Engracia Madejon 《Soil & Tillage Research》2006,90(1-2):162-170

To improve soil fertility, efforts need to be made to increase soil organic matter content. Conventional farming practice generally leads to a reduction of soil organic matter. This study compared inorganic and organic fertilisers in a crop rotation system over two cultivation cycles: first crop broad bean (Vicia faba L.) and second crop mixed cropped melon-water melon (Cucumis melo-Citrullus vulgaris) under semi-arid conditions. Total organic carbon (TOC), Kjeldahl-N, available-P, microbial biomass C (Cmic), and N (Nmic), soil respiration and enzymatic activities (protease, urease, and alkaline phosphatase) were determined in soils between the fourth and sixth year of management comparison. The metabolic quotient (qCO₂), the Cmic/Nmic ratio, and the Cmic/TOC ratio were also calculated. Organic management resulted in significant increases in TOC and Kjeldahl-N, available-P, soil respiration, microbial biomass, and enzymatic activities compared with those found under conventional management. Crop yield was greater from organic than conventional fertilizer. The qCO₂ showed a progressive increase for both treatments during the study, although qCO₂ was greater with conventional than organic fertilizer. In both treatments, an increase in the Cmic/Nmic ratio from first to second crop cycle was observed, indicating a change in the microbial populations. Biochemical properties were positively correlated (p < 0.01) with TOC and nutrient content. These results indicated that organic management positively affected soil organic matter content, thus improving soil quality and productivity.  相似文献   

Protection, promotion and support of breast-feeding in Europe: current situation     

Cattaneo A  Yngve A  Koletzko B  Guzman LR;Promotion of Breastfeeding in Europe project 《Public health nutrition》2005,8(1):39-46

OBJECTIVE: To describe the current situation regarding protection, promotion and support of breast-feeding in Europe, as a first step towards the development of a blueprint for action. DESIGN AND SETTING: A questionnaire was completed by 29 key informants and 128 other informants in the EU, including member states, accession and candidate countries. RESULTS: EU countries do not fully comply with the policies and recommendations of the Global Strategy on Infant and Young Child Feeding that they endorsed during the 55th World Health Assembly in 2002. Some countries do not even comply with the targets of the Innocenti Declaration (1990). Pre-service training on breast-feeding practice is inadequate and in-service training achieves only low to medium coverage. The Baby Friendly Hospital Initiative is well developed only in three countries; in 19 countries, less than 15% of births occur in baby-friendly hospitals. The International Code of Marketing of Breastmilk Substitutes, endorsed in 1981 by all countries, is not fully applied and submitted to independent monitoring. The legislation for working mothers meets on average the International Labour Organization standards, but covers only women with full formal employment. Voluntary mother-to-mother support groups and trained peer counsellors are present in 27 and 13 countries, respectively. Breast-feeding rates span over a wide range; comparisons are difficult due to use of non-standard methods. The rate of exclusive breast-feeding at 6 months is low everywhere, even in countries with high initiation rates. CONCLUSIONS: EU countries need to revise their policies and practices to meet the principles inscribed in the Global Strategy on Infant and Young Child Feeding in order to better protect, promote and support breast-feeding.  相似文献   

A rapid method for the determination of chlorine, phosphorus, and sulfur in flours of grains and legumes using wavelength dispersive x-ray flourescence spectrometry     

T Pérez Ruiz  M Hernández Córdoba  R González 《Journal of the Association of Official Analytical Chemists》1991,74(4):625-626

A rapid method for the determination of chlorine, phosphorus, and sulfur in commercial flours of wheat, barley, maize, rice, field bean, and soybean by wavelength dispersive x-ray fluorescence spectrometry has been developed. The flours are strained through a 425 microns sieve, then pelletized and measured. The total analysis time for the quantitation of chlorine, phosphorus, and sulfur is less than 20 min per sample. Calibration is carried out using a standard additions method with mixed standards. The method is accurate and precise, and appears to be adequate for routine analyses.  相似文献   

New device for direct extraction of volatiles in solid samples using SPME.   总被引：10，自引：0，他引：10  

J Ruiz  J Ventanas  R Cava 《Journal of agricultural and food chemistry》2001,49(11):5115-5121

A new device that allows extraction of volatiles from solid materials by SPME, avoiding preparation of the sample, was designed and tested in two different food products. Volatiles from dry-cured ham and canned liver sausage were analyzed by headspace SPME (HS SPME) and by using a new device that protects the SPME fiber in the core of the solid material. Volatile profiles generated by using both methods of extraction were very similar in both products. Compounds that have been previously highlighted as quality markers, such as products from oxidative degradation of lipids, products from Strecker degradation of amino acids, or terpenes, were satisfactorily extracted by SPME coupled to the device for direct extraction. In addition, by using this method no laboratory contaminants were extracted, whereas some major laboratory solvents were presented in the chromatogram using the HS SPME method. However, coefficients of variation were higher when performing the direct sampling procedure. This new device appears to have potential as a simple method for extracting volatiles in solid materials while at the same time avoiding taking samples.  相似文献