Stochastic pulse regulation in bacterial stress response     

Locke JC  Young JW  Fontes M  Hernández Jiménez MJ  Elowitz MB 《Science (New York, N.Y.)》2011,334(6054):366-369

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Pressure dependence of the superconducting transition temperature of magnesium diboride     

Monteverde M  Núñez-Regueiro M  Rogado N  Regan KA  Hayward MA  He T  Loureiro SM  Cava RJ 《Science (New York, N.Y.)》2001,292(5514):75-77

We studied the pressure and temperature dependence of the electrical resistivity of the superconducting compound magnesium diboride (MgB(2)). The superconducting transition temperature decreases monotonically with pressure, being parabolic or linear, depending on samples. The rate of decrease under pressure is higher than in conventional superconductors. We discuss our results in terms of the semimetallic character of the electronic band structure of MgB(2).  相似文献   

Classification of pumpkin seed oils according to their species and genetic variety by attenuated total reflection Fourier-transform infrared spectroscopy     

Saucedo-Hernández Y  Lerma-García MJ  Herrero-Martínez JM  Ramis-Ramos G  Jorge-Rodríguez E  Simí-Alfonso EF 《Journal of agricultural and food chemistry》2011,59(8):4125-4129

Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), followed by multivariate treatment of the spectral data, was used to classify seed oils of the genus Cucurbita (pumpkins) according to their species as C. maxima, C. pepo, and C. moschata. Also, C. moschata seed oils were classified according to their genetic variety as RG, Inivit C-88, and Inivit C-2000. Up to 23 wavelength regions were selected on the spectra, each region corresponding to a peak or shoulder. The normalized absorbance peak areas within these regions were used as predictors. Using linear discriminant analysis (LDA), an excellent resolution among all categories concerning both Cucurbita species and C. moschata varieties was achieved. The proposed method was straightforward and quick and can be easily implemented. Quality control of pumpkin seed oils is important because Cucurbita species and genetic variety are both related to the pharmaceutical properties of the oils.  相似文献   

Aeromonas hydrophila-associated septicemia in captive crocodiles (Crocodylus johnstoni and Crocodylus porosus)     

Roh YS  Park H  Cho HU  Cho A  Islam MR  Cho HS  Lim CW  Kim B 《Journal of zoo and wildlife medicine》2011,42(4):738-742

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Ultrasonographic assessment of maternal cardiac function and peripheral circulation during normal gestation in dogs     

Blanco PG  Tórtora M  Rodríguez R  Arias DO  Gobello C 《Veterinary journal (London, England : 1997)》2011,190(1):154-159

The aim of this study was to describe changes in cardiac morphology, systolic function and some peripheral hemodynamic parameters during normal pregnancy in dogs. Twenty healthy bitches, 10 pregnant (PG) and 10 non-pregnant controls (CG), were evaluated every 10 days using echocardiography from day 0 of the estrus cycle to parturition or to day 65 for the PG and CG groups, respectively. Systolic blood pressure (SBP) and uterine artery resistance index (RI) were also assessed. Throughout the study, the shortening fraction and cardiac output increased up to 30% vs. 5% (P<0.01) and 45% vs. 2% (P<0.01) in the PG and CG groups, respectively. In contrast, SBP and RI diminished up to 20% vs. 1% (P<0.01) and 29% vs. 0% (P<0.01) in the PG and CG groups, respectively. In conclusion, a decrease in afterload, an increase in cardiac output and cardiac hypertrophy appear to be the result of the hemodynamic modifications occurring during pregnancy in dogs.  相似文献   

Partial replacement of Fe(o,o‐EDDHA) by humic substances for Fe nutrition and fruit quality of citrus     

Mar Cerdán  Antonio Sánchez‐Sánchez  Margarita Juárez  Juan J. Sánchez‐Andreu  Juana D. Jordá  Dolores Bermúdez 《植物养料与土壤学杂志》2007,170(4):474-478

The most widely used Iron (Fe) fertilizer in calcareous soils is the synthetic chelate Fe(o,o‐EDDHA). However, humic substances are occasionally combined with Fe chelates in drip irrigation systems in order to lower costs. We investigated the effect of various mixtures of Fe(o,o‐EDDHA) and a commercially available humic substance on Fe availability in a calcareous soil from Murcia, Spain (in vitro experiment) and on leaf Fe content and fruit‐quality attributes of Citrus macrophylla (field experiment). In the in vitro experiment, a calcareous soil was incubated for 15 d with solutions of sole Fe(o,o‐EDDHA) and humic substance and of a mixture of humic substance and Fe(o,o‐EDDHA) to determine the dynamics of available Fe. While the mixture did not significantly increase the available soil Fe, it did decrease the rate of Fe retention in the surface soil compared to sole Fe(o,o‐EDDHA). In the field experiment, the substitution in the application solution of 67% of Fe(o,o‐EDDHA) by commercial humic substance increased leaf P in lemon trees from 0.19% with sole Fe(o,o‐EDDHA) to 0.30% and leaf Fe from 94 mg kg^–1 to 115 mg kg^–1. Some quality parameters like vitamin C content and peel thickness were also improved with a partial substitution of Fe(o,o‐EDDHA) by humic substances. We conclude that a partial substitution of commercial Fe chelates by humic substance can improve crop Fe uptake and may thus be economically attractive. The underlying physiological mechanisms and ecological implications require further studies.  相似文献   

Complexation of several fungicides with beta-cyclodextrin: determination of the association constants and isolation of the solid complexes     

Lezcano M  Novo M  Al-Soufi W  Rodríguez-Núñez E  Tato JV 《Journal of agricultural and food chemistry》2003,51(17):5036-5040

The formation of inclusion complexes with beta-cyclodextrin was studied for several popular fungicides of different types: prochloraz, 2-phenylphenol, thiophanate methyl, 8-hydroxyquinoline, and benalaxyl. Phase solubility diagrams showed that in all cases complexation takes place, leading to an important increase of water solubility in prochloraz and benalaxyl. Equilibrium association constants could be determined from the phase solubility data and from NMR titrations in the case of 2-phenylphenol. Because of the low solubility of the complex formed between 8-hydroxyquinoline and beta-cyclodextrin, the corresponding association constant could not be determined. The solid complexes of fungicide-cyclodextrin were prepared and isolated by different methods. The isolation of real complexes and not physical mixtures was confirmed in the cases of prochloraz, 2-phenylphenol, and benalaxyl by differential scanning calorimetry.  相似文献   

Effect of cooking temperatures on chemical changes in species of organic arsenic in seafood   总被引：2，自引：0，他引：2  

Devesa V  Martínez A  Súñer MA  Vélez D  Almela C  Montoro R 《Journal of agricultural and food chemistry》2001,49(5):2272-2276

The concentrations of arsenobetaine (AB), tetramethylarsonium ion (TMA(+)), and trimethylarsine oxide (TMAO) were determined in samples of sole, dory, hake, and sardine, raw and after being subjected to cooking processes--baking, frying, and grilling--at various temperatures. In all cases, the temperature attained inside the product during the cooking process was measured. The arsenic species extracted from the samples with methanol/water were separated by means of a column switching technique between a PRP-X100 column and a PRP-X200 column. AB was detected by hydride generation atomic absorption spectrometry, whereas TMA(+) and TMAO were detected by hydride generation atomic fluorescence spectrometry. The results obtained showed that, in all of the types of seafood studied, TMA(+) appeared after cooking, possibly because heating facilitates decarboxylation of AB to TMA(+).  相似文献   

Effect of the addition of sewage sludge as a fertilizer on a sandy vineyard soil     

Bravo-Martín-Consuegra  Sandra  García-Navarro  Francisco Jesús  Amorós-Ortíz-Villajos  José Ángel  Pérez-de-los-Reyes  Caridad  Higueras  Pablo L. 《Journal of Soils and Sediments》2016,16(4):1360-1365

Purpose

The application of sludge from wastewater in agriculture has increased in recent years, and it is therefore important to assess the effect that such treatment has on both the soil and the plant. The aim of the study described here was to ascertain whether there is a variation in the properties of the soil and to determine if this addition has an impact on the plant.

Materials and methods

The area of investigation was close to the municipality of Villarrubia de los Ojos (Ciudad Real). In this work, six samples were taken from the surface horizon in the studied plot at a depth of 35 cm. A further three samples were taken: (i) a surface horizon of a soil close to the area under investigation but without treatment (control sample), (ii) a sample of sludge from the wastewater treatment plant and (iii) a sample of the mixture used by farmers as fertilizer. Laboratory tests were conducted in accordance with the SCS-USDA (1972) guidelines. Trace element samples were analysed by X-ray fluorescence spectrophotometry (Philips PW 2404).

Results and discussion

The parcel of land studied is dominated by a sandy texture (88.3 % sand), and a decrease in pH was observed in areas in which the mixture (manure + sludge) was added (pH?=?8.0) compared to areas in which fertilizer was not applied (pH?=?8.5). It was observed that the addition of the compound led to an increase in the electrical conductivity of the soil. The trace elements can be organized into two groups based on the results obtained in this study. One group contains the trace elements that were only present in the rows that were treated with the fertilizer. The other group of trace elements was mobilized throughout the whole plot.

Conclusions

The application of sewage sludge on agricultural soils can be very useful as an organic amendment because it produces an increase in soil organic matter. However, sewage sludge must be applied with caution due to the changes in soil chemical properties (for example, pH and E.C.). The use of this type of waste for prolonged periods of time can cause problems of contamination in the soil.

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Ozone Biomonitoring with Bel-W3 Tobacco Plants in the City of Valencia (Spain)     

Vicent Calatayud  María José Sanz  Esperanza Calvo  Júlia Cerveró  Wolfgang Ansel  Andreas Klumpp 《Water, air, and soil pollution》2007,183(1-4):283-291

A biomonitoring study using the ozone-sensitive bioindicator plant Nicotiana tabacum cv. Bel-W3 was conducted in the city of Valencia (eastern Spain) and surrounding areas in 2002. Plants were exposed to ambient air at seven sites, including four traffic-exposed urban sites, a large urban garden and a suburban and a rural station, for six consecutive 2-week periods using highly standardised methods. Foliar injury was registered at all stations in at least one of the exposure periods. The urban stations submitted to intense traffic showed lower ozone injury than the less traffic-exposed stations. Strong changes in the intensity of ozone injury were observed for the different exposure periods. Leaf injury was significantly related to both mean ozone values (24 and 12 h means) and cumulative exposure indices (AOT20, AOT40). However, correlation strength was moderate (r _s?=?0.39 to 0.58), suggesting that the plant response to ozone was modified by environmental factors. The use of sensitive bioindicators like tobacco Bel-W3 in cities provides complementary information to that of continuously operating air quality monitors, as the impact of ambient ozone levels is directly measured.  相似文献