Lignite pre-treatment and its effect on bio-stimulative properties of respective lignite humic acids   总被引：1，自引：0，他引：1  

Zoja Vl kov  Laurent Grasset  Barbora Anto&#x;ov  Miloslav Peka&#x;  Ji&#x;í Ku erík 《Soil biology & biochemistry》2009,41(9):1894-1901

Humic acids originating from South-Moravian lignite were subjected to a comparative study with the aim to assess the alteration of their physico-chemical properties after various lignite pre-treatments. Physical modification was achieved with two organic acids, such as acetic acid and citric acid and chemical modification by nitric acid and hydrogene peroxide in various concentrations. Elemental analysis, solid-state NMR, GC–MS analysis of polyols and size exclusion chromatography were carried out for chemical–physical characterization of obtained humic acids. Their biological effect, in form of potassium and ammonium humates, was tested on maize (Zea mays) seedlings. In these tests, potassium humates achieved far better overall results than ammonium humates. Results were inter-correlated in order to appraise the influence of humic acids physical and chemical properties on biological activity. Surprisingly, fractions with the lowest molecular size (0–35 kDa) showed no correlation with bioactivity results (Pearson coefficient from 0.05 to −0.4). On the contrary, middle-sized fractions (35–175 kDa) showed highly significant positive correlation (Pearson coefficient up to 0.92) and the highest molecular-size-fractions (275–350 kDa) showed negative correlation (Pearson coefficient up to −0.75). These findings were identical for both potassium and ammonium humates. No connection was found between bioactivity of humates and polyols content which was remarkably high; it reached 150 mg per g of humic acids in the most extreme case of 5% hydrogene peroxide pre-treatment. In the final analysis, the preparation mode bore pivotal responsibility for the control of humic acids biological effect and showed the best results for potassium humates obtained from lignite pre-treated by acetic acid and by 2% hydrogen peroxide.  相似文献   

Porcine CD18 mediates Actinobacillus pleuropneumoniae ApxIII species-specific toxicity     

Philippe G.A.C. Vanden Bergh  Laurent L.M. Zecchinon  Thomas Fett    Daniel Desmecht 《Veterinary research》2009,40(4)

Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, produces Apx toxins that are recognized as major virulence factors. Recently, we showed that ApxIIIA-cytotoxic activity specifically targets Sus scrofa leukocytes. Since both LtxA from Aggregatibacter actinomycetemcomitans (aggressive periodontitis in humans) and LktA from Mannheimia haemolytica (pneumonia in ruminants) share this characteristic, respectively towards human and ruminant leukocytes, and because both use the CD18 subunit to interact with their respective LFA-1, we hypothesized that ApxIIIA was likely to bind porcine CD18 to exercise its deleterious effects on pig leukocytes. A β ₂−integrin-deficient ApxIIIA-resistant human erythroleukemic cell line was transfected either with homologous or heterologous CD11a/CD18 heterodimers using a set of plasmids coding for human (ApxIIIA-resistant), bovine (-resistant) and porcine (-susceptible) CD11a and CD18 subunits. Cell preparations that switched from ApxIIIA-resistance to -susceptibility were then sought to identify the LFA-1 subunit involved. The results showed that the ApxIIIA-resistant recipient cell line was rendered susceptible only if the CD18 partner within the LFA-1 heterodimer was that of the pig. It is concluded that porcine CD18 is necessary to mediate A. pleuropneumoniae ApxIIIA toxin-induced leukolysis.  相似文献   

Ultrasonography of the Bovine Respiratory System and Its Practical Application     

Marie Babkine  Laurent Blond 《Veterinary Clinics of North America: Food Animal Practice》2009

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Neurology without the gimmicks     

Laurent Garosi 《Journal of Feline Medicine and Surgery》2009,11(5):339

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Spatial distribution of sediments and transfer properties in soils in a stormwater infiltration basin   总被引：3，自引：2，他引：1  

Patrice Cannavo  Laure Vidal-Beaudet  Béatrice Béchet  Laurent Lassabatère  Sylvain Charpentier 《Journal of Soils and Sediments》2010,10(8):1499-1509

Purpose  

The aim of our study was to characterise the heterogeneity of sediment distribution in a stormwater retention/infiltration basin (Pont de Cheviré, Nantes, France) and to determine the impact of this distribution on water transfer properties in the soil.  相似文献   

Floristic and ecological differences between recent and ancient forests growing on non-acidic soils     

Delphine Sciama  Laurent Augusto  Jean-Luc Dupouey  Maya Gonzalez  Concepción Moares Domínguez 《Forest Ecology and Management》2009

The aim of this work was to investigate differences in soil chemistry and understory composition between recent forests (sites afforested in the last 170 years) and ancient forests growing on non-acidic soils. The study was carried out on hardwood forests at moderate elevation (400–600 m asl) in the Jura Mountains (N.E. France) on four main pedological substrates with different characteristics. The floristic composition of 127 stands from recent forests (n = 65) or ancient forests (n = 62) was surveyed. Some functional traits and the Ellenberg indicator values of the surveyed species were recorded. In addition, the topsoil from 30 stands was analysed. The composition of the flora was analysed by Detrended Correspondence Analysis and the species which were typical of one class of forest age were identified using a chi-square (χ²) test. The difference between forest classes for plant traits, their indicator values, or soil chemistry was tested using the generalized linear model and Bonferroni t-tests (or Kruskall–Wallis tests). The floristic composition of the ancient forests was significantly different from that of the recent forests and was characterized by a high occurrence of shrub species in recent forests. These differences were associated with higher specific leaf area, low-range seeds dispersal, and some life forms like geophytes. There was no clear difference in soil chemistry between the two classes of forests, except for δ¹⁵N values. The weakness of the difference in the soil between ancient and recent forests suggested that changes in soil chemistry caused by a former agricultural land use were not responsible for the differences in understory composition recorded. The differences in functional traits between the two forest classes supported this conclusion. We finally concluded that (i) past land use modifies the vegetation composition of current forests, even on neutral soils and that (ii) in our context, biological filters were probably responsible for these changes.  相似文献   

Erratum to: Incidence and Characterization of <Emphasis Type="Italic">Potato Virus Y</Emphasis> in Seed Potatoes in Tunisia     

Sonia Boukhris-Bouhachem  J. Rouze-Jouan  N. Khamassi  Fattouma Djilani-Khouadja  Hatem Fakhfakh  Laurent Glais  Michel Tribodet  Camille Kerlan 《Potato Research》2011,54(3):283

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Whiptail Stingray Injury     

Simon Laurent  Olivier Martinet  Helene Cuq  Alain Rind  Philippe Durasnel  Claire Lenne  Renaud Blondé 《The Forestry Chronicle》2018,29(2):243-247

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An inconvenient truth about xylem resistance to embolism in the model species for refilling <Emphasis Type="Italic">Laurus nobilis</Emphasis> L.     

Laurent J. Lamarque  Déborah Corso  José M. Torres-Ruiz  Eric Badel  Timothy J. Brodribb  Régis Burlett  Guillaume Charrier  Brendan Choat  Hervé Cochard  Gregory A. Gambetta  Steven Jansen  Andrew King  Nicolas Lenoir  Nicolas Martin-StPaul  Kathy Steppe  Jan Van den Bulcke  Ya Zhang  Sylvain Delzon 《Annals of Forest Science》2018,75(3):88

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COMPARISON OF THORACIC ULTRASONOGRAPHY AND RADIOGRAPHY FOR THE DETECTION OF INDUCED SMALL VOLUME PNEUMOTHORAX IN THE HORSE          下载免费PDF全文

Jessica Partlow  Florent David  Luanne Michelle Hunt  Fabien Relave  Laurent Blond  Manuel Pinilla  Jean‐Pierre Lavoie 《Veterinary radiology & ultrasound》2017,58(3):354-360

Small volume pneumothorax can be challenging to diagnose in horses. The current standard method for diagnosis is standing thoracic radiography. We hypothesized that thoracic ultrasonography would be more sensitive. Objectives of this prospective, experimental study were to describe a thoracic ultrasound method for detection of small volume pneumothorax in horses and to compare results of radiography and ultrasound in a sample of horses with induced small volume pneumothorax. Six mature healthy horses were recruited for this study. For each horse, five 50 ml air boluses were sequentially introduced via a teat cannula into the pleural space. Lateral thoracic radiographs and standardized ultrasound (2D and M‐mode) examinations of both hemithoraces were performed following administration of each 50 ml air bolus. Radiographs and ultrasound images/videos were analyzed for detection of pneumothorax by four independent investigators who were unaware of treatment status. Sensitivity, specificity, positive predictive values, negative predictive values, and agreement among investigators (Kappa test, κ) were calculated for radiography, 2D and M‐mode ultrasound. Comparisons were made using a chi‐squared exact test with significance set at P < 0.05. Two‐dimensional (84%) and M‐mode (80%) ultrasound were more sensitive than radiography (48%) for pneumothorax detection (P = 0.02 and P = 0.04, respectively). Specificity and positive predictive values were similar for all three imaging modalities (P = 1). Agreement between investigators for pneumothorax detection was excellent for 2D ultrasound (κ = 1), very good for M‐mode ultrasound (κ = 0.87), and good for radiography (κ = 0.79). Findings from this experimental study supported the use of thoracic ultrasonography as a diagnostic method for detecting pneumothorax in horses.  相似文献