Picometer-scale electronic control of molecular dynamics inside a single molecule     

Lastapis M  Martin M  Riedel D  Hellner L  Comtet G  Dujardin G 《Science (New York, N.Y.)》2005,308(5724):1000-1003

Tunneling electrons from a low-temperature (5 kelvin) scanning tunneling microscope were used to control, through resonant electronic excitation, the molecular dynamics of an individual biphenyl molecule adsorbed on a silicon(100) surface. Different reversible molecular movements were selectively activated by tuning the electron energy and by selecting precise locations for the excitation inside the molecule. Both the spatial selectivity and energy dependence of the electronic control are supported by spectroscopic measurements with the scanning tunneling microscope. These experiments demonstrate the feasibility of controlling the molecular dynamics of a single molecule through the localization of the electronic excitation inside the molecule.  相似文献   

Isoflurane measurement error using short wavelength infrared techniques in horses: influence of fresh gas flow and pre-anaesthetic food deprivation     

Dujardin CL  Gootjes P  Moens Y 《Veterinary anaesthesia and analgesia》2005,32(2):101-106

OBJECTIVE: To quantify the isoflurane measurement error arising from the use of short wavelength infrared (IR) anaesthetic gas analysis during low flow anaesthesia in horses. STUDY DESIGN: Prospective clinical study. ANIMAL POPULATION: Sixty-four client-owned horses referred for elective or emergency surgery (age 1-16 years, body mass 400-650 kg). MATERIALS AND METHODS: Horses were divided into four groups based on duration of pre-anaesthetic food deprivation period (FDP) and fresh gas flow during anaesthesia: a high flow group with normal FDP (n = 16) and three groups with low flow and normal (n = 29), long (n = 5) or no (n = 14) FDP, respectively. Circuit isoflurane concentrations were measured simultaneously using a short wavelength (methane-sensitive) analyser (Datex Capnomac Ultima) and a long wavelength (methane-insensitive) analyser (Hewlett Packard M 1025 B) for at least 60 minutes. The difference between the readings of both analysers gave the isoflurane measurement error of short wavelength IR analysis, from which the circuit methane concentration was calculated. RESULTS: In the low flow groups, isoflurane measurement error increased over time, whereas in the high flow group, error remained constant after an initial rise in the first 15 minutes. The isoflurane measurement error was significantly lower (p < 0.005) in the high flow group compared with the low flow-normal FDP group from 15 to 60 minutes. Compared to the low flow - normal FDP group, isoflurane measurement error was significantly smaller (p < 0.001, from 15 to 60 minutes) in the low flow-long FDP group and significantly larger (p = 0.016, at 60 minutes) in the low flow-no FDP group. Within the low flow-no FDP group, values in colic cases did not differ from those in noncolic cases (p > 0.7). CONCLUSIONS: Isoflurane measurement using short wavelength IR absorption is inaccurate. The fresh gas flow and duration of pre-anaesthetic food deprivation influence the isoflurane measurement error during anaesthesia in horses. CLINICAL RELEVANCE: Short wavelength IR analysers are not reliable for isoflurane measurement during (low flow) anaesthesia in horses.  相似文献   

Determination of the pharmacokinetic-pharmacodynamic cut-off values of marbofloxacin in horses to support the establishment of a clinical breakpoint for antimicrobial susceptibility testing     

Alain Bousquet-Mélou  Marc Schneider  Farid El Garch  Diane C. Broussou  Aude A. Ferran  Elodie A. Lallemand  Cyrielle Triboulloy  Peter Damborg  Pierre-Louis Toutain 《Equine veterinary journal》2021,53(5):1047-1055

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Effects of seedbed structure and water content at sowing on the development of soil surface crusting under rainfall     

Aude Gallardo-Carrera  Joël Lonard  Yves Duval  Carolyne Dürr 《Soil & Tillage Research》2007,95(1-2):207-217

This study was carried out to observe the dynamics of crust formation on the soil surface under field conditions and analyse the effects of seedbed structure and water content on soil surface crusting. Seedbed sensitivity to crusting was also estimated in the laboratory by stability tests on aggregates. We observed 57 plots during the sowings of spring and autumn crops in fields in Northern France (Estrees-Mons, 50°N latitude, 3°E longitude). The soil is an Orthic Luvisol according to the FAO classification (0.17–0.25 g g⁻¹ clay and 0.02 g g⁻¹ organic matter on average). Visual assessments in situ were performed and photographs taken of crust stages on delimited areas, each 5 mm of cumulated rainfall since sowing. In 2004–2005, the seedbeds were characterised by their distribution of aggregate sizes and tests of aggregate stabilities of surface samples kept with their water content at sowing. A penetrometer was used to measure crust resistance and estimate its thickness. These data were analysed to detect the cumulative rainfall values needed for the initiation and development of the successive stages of crusts. A fully developed structural crust (stage F1) required 13, 22, 27 mm cumulated rainfall respectively for seedbeds with proportions of clods over 2 cm ranging from 0 to 0.15 (fine seedbed), 0.15 to 0.30 (medium seedbed), >0.30 g g⁻¹ (coarse seedbed). Aggregate stability measured on samples kept at sowing water content was low for soil with low water content (<0.17 g g⁻¹) but increased sharply for water contents over 0.17 g g⁻¹. Stage F1 was reached more rapidly (only 11 mm versus 19 mm cumulated rainfall) only for fine seedbeds with less than 0.15 g g⁻¹ of clods over 2 cm and with a low water content at sowing, The stage of 50% of soil surface covered with sedimentary crusts was reached for 85 mm for fine seedbed versus 120 mm for medium seedbed. The mean penetrometer resistance of dry crusts was 0.55 ± 0.43 MPa for stage F1 and 3.54 ± 0.83 MPa for a sedimentary stage; mean penetrometer resistance increased continuously with cumulated rainfall and was much lower for wet crusts. These quantitative data gathered under field conditions constitute the first step towards the prediction of soil surface crusting. The cumulative rainfalls were used in order to estimate the risk of occurrence of structural and sedimentary crusts forming during crop emergence with several types of seedbeds.  相似文献   

Metal Accumulation by Woody Species on Contaminated Sites in the North of France     

Aude Migeon  Pierre Richaud  Frédéric Guinet  Michel Chalot  Damien Blaudez 《Water, air, and soil pollution》2009,204(1-4):89-101

Metal accumulation was investigated in a range of woody species that were planted on Cd-, Zn- and Pb- polluted sites in North of France. The study is unique in that we directly compare a large number of woody species (25). The highest accumulation of Zn and Cd was found in the Salicaceae family members with up to 950 mg Zn kg^?1 dry weight (DW) and 44 mg Cd kg^?1 DW in leaves of Populus tremula × Populus tremuloides. Zn content was positively correlated with Cd content, both in leaves and stems. Pb concentration was generally low and was species-independent. Oak and birch species accumulated more Mn as compared to other woody species. A seasonal variation in metal accumulation could be found. Although soil compositions and metal bioavailabilities differed amongst the experimental sites chosen in this study, variation of metal concentrations within a given species was small. High bioconcentration factors for poplar and willow suggested the high potential of these species over other woody species for metal accumulation. Taken together, these data suggest that poplar and willow species are good candidates for phytoremediation programmes.  相似文献   

Land use change and soil carbon pools: evidence from a long-term silvopastoral experiment     

Dario A. Fornara  Rodrigo Olave  Paul Burgess  Aude Delmer  Matthew Upson  Jim McAdam 《Agroforestry Systems》2018,92(4):1035-1046

Multi-functional silvopastoral systems provide a wide range of services to human society including the regulation of nutrients and water in soils and the sequestration of atmospheric carbon dioxide (CO₂). Although silvopastoral systems significantly contribute to enhance aboveground carbon (C) sequestration (e.g. C accumulation in woody plant biomass), their long-term effects on soil C pools are less clear. In this study we performed soil physical fractionation analyses to quantify the C pool of different aggregate fractions across three land use types including (1) silvopastoral system with ash trees (Fraxinus excelsior L.), (2) planted woodland with ash trees, and (3) permanent grassland, which were established in 1989 at Loughgall, Northern Ireland, UK. Our results show that 26 years after the conversion of permanent grassland to either silvopastoral or woodland systems, soil C (and N) stocks (0–20 cm depth) did not significantly change between the three land use types. We found, however, that permanent grassland soils were associated with significantly higher C pools (g C kg^?1 soil; P < 0.03) of the large macro-aggregate fraction (> 2 mm) whereas soil C pools of the micro-aggregate (53–250 μm) and silt and clay (< 53 μm) fractions were significantly higher in the silvopastoral and woodland systems (P < 0.05). A key finding of this study is that while tree planting on permanent grassland may not contribute to greater soil C stocks it may, in the long-term, increase the C pool of more stable (recalcitrant) soil micro-aggregate and silt and clay fractions, which could be more resilient to environmental change.  相似文献   

Tuning of natural killer cell reactivity by NKp46 and Helios calibrates T cell responses   总被引：1，自引：0，他引：1  

Narni-Mancinelli E  Jaeger BN  Bernat C  Fenis A  Kung S  De Gassart A  Mahmood S  Gut M  Heath SC  Estellé J  Bertosio E  Vely F  Gastinel LN  Beutler B  Malissen B  Malissen M  Gut IG  Vivier E  Ugolini S 《Science (New York, N.Y.)》2012,335(6066):344-348

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Objective effectiveness of and indications for laser‐assisted turbinectomy in brachycephalic obstructive airway syndrome     

Nai‐Chieh Liu  Marie‐Aude Genain  Lajos Kalmar  David R. Sargan  Jane F. Ladlow 《Veterinary surgery : VS》2019,48(1):79-87

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Cardiopulmonary effects and anaesthesia recovery quality in horses anaesthetized with isoflurane and low‐dose S‐ketamine or medetomidine infusions          下载免费PDF全文

M Paula Larenza Menzies  Simone K Ringer  Aude Conrot  Regula Theurillat  Katharina Kluge  Annette PN Kutter  Michelle Jackson  Wolfgang Thormann  Regula Bettschart‐Wolfensberger 《Veterinary anaesthesia and analgesia》2016,43(6):623-634

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Host evolution in Mastomys natalensis (Rodentia: Muridae): An integrative approach using geometric morphometrics and genetics          下载免费PDF全文

Aude LALIS  Allowen EVIN  Marc JANIER  Lamine KOIVOGUI  Christiane DENYS 《Integrative zoology》2015,10(6):505-514

The commensal rodent Mastomys natalensis is the natural reservoir of Lassa arenavirus (LASV), which causes hemorrhagic fever in West Africa. To study a possible effect of the virus on phenotypic and genotypic variation of its persistently infected host, we compared LASV‐positive and non‐infected wild‐caught M. natalensis. The LASV effects on the phenotypic variation were explored using standard external morphometric measurements, geometric morphometric analyses of the cranial size and shape, and brain case volume. The genetic variability of M. natalensis specimens was assessed using 9 polymorphic microsatellite markers. Independent of sex and age, LASV‐infected animals had smaller external body measurements, reproductive organs, skull size and brain case volume. Cranial shape differences between the 2 groups are represented by a lateral constriction of the entire skull. The genetic variability revealed consanguinity only among the LASV‐positive rodents. We hypothesize that growth impairment may result in a selective disadvantage for LASV‐infected M. natalensis, leading to a preferably commensal lifestyle in areas where the LAVS is endemic and, thereby, increasing the risk of LASV transmission to humans.  相似文献