49 research outputs found
Os et articulations : le sport soumet notre squelette à rude épreuve... pour le meilleur et pour le pire !
No full textDossier sur les os et articulations du sportif. Sommaire : 'Petites histoires d'os' (mille et une choses étonnantes à propos de notre squelette), 'Mythes et croissance' (sport et croissance : interview de Daniel Courteix, directeur du laboratoire de biologie des APS à Clermont 2), 'Entre marbre et verre' (interview de Martine Le Merrer, responsable du centre de référence sur les maladies osseuses constitutionnelles à l'hôpital Necker), 'La série Urgences' (traumatologie articulaire et osseuse : interview de Jacques Rodineau, médecin spécialiste dans la rééducation fonctionnelle à la Pitié-Salpêtrière), 'La mort des os' (interview de Didier Hannouche, chirurgien orthopédiste spécialiste des nécroses osseuses et des techniques de reconstruction), 'Squelette en voie de disparition' (vieillissement, ostéoporose : interview de Martine Cohen-Solal, rhumatologue spécialiste des maladies osseuses
Benzylchlorocarbene: origins of Arrhenius curvature in the kinetics of the 1,2-H shift rearrangement
No full textBenzylchlorocarbene (1, BCC) was generated photochemically from benzylchlorodiazirine (2) in isooctane, methylcyclohexane (MCH), and tetrachloroethane (TCE) at temperatures from similar to 30 to -75 degrees C. At -70 degrees C in isooctane, the identified products included Z/E-beta-chlorostyrenes 4 (46.6%), alpha-chlorostyrene 5 (2.4%), 1,1-dichloro-2-phenylethane 6 (1.9%), a BCC-isooctane insertion product 8 (5.5%), carbene dimers 9 (3.8%), and azine 3 (30%). The significant incursion of intermolecular products 3, 8, and 9 implies that laser flash photolytic (LFP) kinetic data for the decay of BCC obtained at low temperature is biased and should not be employed in Arrhenius analyses. Accordingly, previously obtained curved Arrhenius correlations for BCC do not necessarily implicate quantum mechanical tunneling (QMT) in the 1,2-H shift rearrangement of BCC to 4. Similarly in MCH, where BCC affords a solvent insertion product in similar to 44-53% yield, the curved Arrhenius correlation (Figure 1) cannot be readily interpreted. In polar solvents such as TCE, clean H-shift reactions of BCC are obtained even at -71 degrees C; an Arrhenius correlation of LFP kinetic data is linear from 3 to -71 degrees C (Figure 2), affording E-a = 3.2 kcal mol(-1) and log A = 10.0 s(-1). Therefore, QMT does not appear to play a major role in the 1,2-H shift rearrangement of BCC at ambient or near ambient temperature in solution.PT: J; CR: BONNEAU R, 1996, J AM CHEM SOC, V118, P3829 DEAN JA, 1992, LANGES HDB CHEM DIX EJ, 1993, J AM CHEM SOC, V115, P10424 DOX AW, 1941, ORG SYNTH, V1, P5 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 ISAACS NS, 1995, PHYSICAL ORGANIC CHE, P304 JACKSON JE, 1988, J AM CHEM SOC, V110, P5595 KAZANIS S, 1991, J PHYS CHEM-US, V95, P4430 KEATING AE, 1997, COMMUNICATION 0804 LAVILLA JA, 1989, J AM CHEM SOC, V111, P6877 LAVILLA JA, 1990, TETRAHEDRON LETT, V31, P5109 LIU MTH, 1984, TETRAHEDRON, V40, P887 LIU MTH, 1985, CHEM COMMUN, P982 LIU MTH, 1985, J ORG CHEM, V50, P3218 LIU MTH, 1990, J AM CHEM SOC, V112, P3915 LIU MTH, 1992, J AM CHEM SOC, V114, P3604 LIU MTH, 1992, J PHOTOCH PHOTOBIO A, V63, P115 LIU MTH, 1994, ACCOUNTS CHEM RES, V27, P287 LIU MTH, 1994, J PHOTOCH PHOTOBIO A, V84, P133 MODARELLI DA, 1992, J AM CHEM SOC, V114, P7034 MODARELLI DA, 1993, J AM CHEM SOC, V115, P470 MOSS RA, 1987, J AM CHEM SOC, V109, P4341 MOSS RA, 1990, J AM CHEM SOC, V112, P1638 MOSS RA, 1994, ADV CARBENE CHEM, V1, P59 MOSS RA, 1996, J AM CHEM SOC, V118, P12588 MOSS RA, 1997, CHEM COMMUN 0321, P617 MOSS RA, 1997, TETRAHEDRON LETT, V38, P7049 STORER JW, 1993, J AM CHEM SOC, V115, P10426 SUGIYAMA MH, 1992, J AM CHEM SOC, V114, P966 TOMIOKA H, 1984, J AM CHEM SOC, V106, P454 WHITE WR, 1992, J ORG CHEM, V57, P2841 WIERLACHER S, 1993, J AM CHEM SOC, V115, P8943 YEN VQ, 1962, ANN CHIM, V7, P785; NR: 33; TC: 8; J9: J ORG CHEM; PG: 7; GA: ZM109Source type: Electronic(1
Inferior Thyroid Artery Injury After Attempts of Internal Jugular Venous Catheterization
No full text[No abstract available]Abbott G, 2001, BRIT J ANAESTH, V86, P143, DOI 10.1093-bja-86.1.143; Cuhaci B, 2000, AM J NEPHROL, V20, P476, DOI 10.1159-000046203; Jeganath V, 2001, BRIT J ANAESTH, V87, P302, DOI 10.1093-bja-87.2.302; MACGEE DC, 2003, NEW ENGL J MED, V348, P1123; Merrer J, 2001, JAMA-J AM MED ASSOC, V286, P700, DOI 10.1001-jama.286.6.700; Peces R, 1998, NEPHROL DIAL TRANSPL, V13, P1009, DOI 10.1093-ndt-13.4.1009; Randolph AG, 1996, CRIT CARE MED, V24, P2053, DOI 10.1097-00003246-199612000-00020; Ruesch S, 2002, CRIT CARE MED, V30, P454, DOI 10.1097-00003246-200202000-00031; Timsit JF, 1998, CHEST, V114, P207, DOI 10.1378-chest.114.1.20733
Kinetic and spectroscopic properties of carbene-diazirine ylides
No full textThe formation of a metastable carbene-diazirine ylide (CDY), characterized by an UV absorption spectrum in the range of 270-290 nm and yielding azine by rearrangement, is shown to be a general process in the photolysis of diazirines. However, the yield of formation and the lifetime of CDY greatly depend on the system considered. The decreasing value of the rate constant of the reaction, carbene + diazirine --> CDY, from similar to 10(9) M-1 s(-1) for singlet dialkylcarbenes, Ad: (adamantylidene) and BCN: (bicyclo[3.3.1]non-9-ylidene), to similar to 10(8) M-1 s(-1) for benzylchlorocarbene and to similar to 10(6) M-1 s(-1) for cyclopropyl and phenylchlorocarbenes, reflects the decreasing reactivity of these carbenes. The lifetime of these ylides is determined by the value of the activation energy barrier for their rearrangement to azine, E-a approximate to 15.5 kcal/mol for dialkylcarbenes, approximate to 11.5 kcal/mol fur alkylchlorocarbenes, and <10 kcal/mol for phenylchlorocarbene. This decrease of E-a is related to the strong stabilization of the azine when proceeding from CR2=N-N=CR2 to Ph-CCl=N-N=CCl-Ph. Another mechanism for the formation of azine, by a second-order reaction of the diazo isomer of the diazirine, is clearly identified in the case of photolysis of the BCN(N-2) diazirine.PT: J; CR: BONNEAU R, 1989, J AM CHEM SOC, V111, P5974 BONNEAU R, 1992, J PHOTOCH PHOTOBIO A, V68, P97 BONNEAU R, 1997, PURE APPL CHEM, V69, P979 BONNEAU R, 1998, J PHOTOCH PHOTOBIO A, V116, P9 BRINKER UH, 1998, ADV CARBENE CHEM, V2 DOYLE MP, 1987, J ORG CHEM, V52, P1619 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 JACKSON JE, 1988, J AM CHEM SOC, V110, P5595 LIU MTH, 1992, J AM CHEM SOC, V114, P3604 LIU MTH, 1992, J ORG CHEM, V57, P2483 LIU MTH, 1992, J PHOTOCH PHOTOBIO A, V63, P115 LIU MTH, 1994, INT J CHEM KINET, V26, P1179 LIU MTH, 1994, J PHOTOCH PHOTOBIO A, V84, P133 LIU MTH, 1994, RES CHEM INTERMEDIAT, V20, P195 LIUEAU R, 1989, J PHYS CHEM-US, V93, P7300 MERRER DC, 1998, J ORG CHEM, V63, P3010 MOSS RA, 1990, J AM CHEM SOC, V112, P1638 MOSS RA, 1990, J AM CHEM SOC, V112, P5642 OIDA S, 1967, CHEM PHARM BULL, V15, P545 OIDA S, 1968, CHEM PHARM BULL, V16, P654 SHUSTOV GV, 1999, CAN J CHEM, V77, P540 TURRO NJ, 1980, J AM CHEM SOC, V102, P7576; NR: 22; TC: 8; J9: J PHYS CHEM A; PG: 6; GA: 311EYSource type: Electronic(1
Effect of substituents on the thermal decomposition of diazirines: Experimental and computational studies
No full textThe thermal decomposition of phenylehlorodiazirine (1), phenyl-n-butyldiazirine (2), and 2-adamantane-2,3'-[3H] diazirine (3) has been studied in solution in the presence Of C-60. The C-60 probe technique indicates that in the decomposition diazirine 1 yielded exclusively phenylchlorocarbene, diazirine 2 yielded mainly a diazo intermediate, and diazirine 3 yielded a mixture of carbene and diazo compound. In the case of diazirine 2, 13% of (E)-1-phenyl-1-pentene resulted from the direct thermal rearrangement of diazirine without the participation of a carbene. As well, the thermal decomposition of these diazirines has been studied theoretically with ab initio and density functional methods. The experimental results are broadly in agreement with the theoretical predictions. The calculations further indicate that the rebound reaction between carbene and molecular nitrogen leading to the formation of a diazo intermediate is an important reaction in the gas-phase decomposition of diazirine.PT: J; CR: AKASAKA T, 2000, J AM CHEM SOC, V122, P7134 AMRICH MJ, 1964, J AM CHEM SOC, V86, P292 BECKE AD, 1988, PHYS REV A, V38, P3098 BECKE AD, 1993, J CHEM PHYS, V98, P5648 BONNEAU R, 1998, ADV CARBENE CHEM, V2, P1 BONNEAU R, 1998, J PHOTOCH PHOTOBIO A, V116, P9 CELEBI S, 1993, J AM CHEM SOC, V115, P8613 DIEDERICH F, 1994, CHEM SOC REV, P243 DIEDERICH F, 1994, NATURE, V369, P199 FIGUERA JM, 1976, AN QUIM, V72, P737 FIGUERA JM, 1978, J CHEM SOC F1, V74, P809 FREY HM, 1962, P CHEM SOC, P79 FREY HM, 1963, J CHEM SOC, P3514 FREY HM, 1964, J CHEM SOC, P4700 FREY HM, 1965, J CHEM SOC, P1700 FREY HM, 1965, J CHEM SOC, P3101 FREY HM, 1966, ADV PHOTOCHEM, V4, P225 FRISCH MJ, 2001, GAUSSIAN 98 REVISION GONZALEZ R, 1995, J ORG CHEM, V60, P2618 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 HEHRE WJ, 1972, J CHEM PHYS, V56, P2257 HIRAO K, 1992, CHEM PHYS LETT, V190, P374 HIRAO K, 1992, CHEM PHYS LETT, V196, P397 HIRAO K, 1992, INT J QUANTUM CHEM S, V26, P517 HIRAO K, 1993, CHEM PHYS LETT, V201, P59 HIRSCH A, 1993, ANGEW CHEM INT EDIT, V32, P1138 HIRSCH A, 1994, CHEM FULLERENES HIRSCH A, 1999, FULLERENES RELATED S ISAEV SD, 1973, ZH ORG KHIM+, V9, P724 JENNINGS BM, 1976, J AM CHEM SOC, V98, P6416 LAUFER AH, 1971, J AM CHEM SOC, V93, P4137 LEE C, 1988, PHYS REV B, V37, P785 LIU M, 1987, CHEM DIAZIRINES LIU MTH, 1972, CAN J CHEM, V50, P3009 LIU MTH, 1972, J PHYS CHEM-US, V76, P797 LIU MTH, 1977, CAN J CHEM, V55, P3596 LIU MTH, 1982, CHEM SOC REV, V11, P127 MERRER DC, 2001, ADV CARBENE CHEM, V3, P53 MODARELLI DA, 1992, J AM CHEM SOC, V114, P7034 MOORE CB, 1964, J CHEM PHYS, V41, P3504 NAKANO H, 1993, J CHEM PHYS, V99, P7983 NAKANO H, 1995, MR2D VER 2 PAULSEN SR, 1960, ANGEW CHEM, V72, P781 PLATZ MS, 1998, ADV CARBENE CHEM, V2, P133 PLATZ MS, 2002, CARBENE CHEM, P27 PLATZ MS, 2002, CARBENE CHEM, P44 ROOS BO, 1987, ADV CHEM PHYS, V69, P399 SCHMIDT MW, 1993, J COMPUT CHEM, V14, P1347 SCHMITZ E, 1961, TETRAHEDRON LETT, P612 SHILOV AE, 1968, TETRAHEDRON LETT, P4177 SMITH AB, 1993, J AM CHEM SOC, V115, P5829 STEVENS IDR, 1990, J CHEM SOC P2, P661 SUZUKI T, 1991, SCIENCE, V254, P1186 SUZUKI T, 1992, J AM CHEM SOC, V114, P7301 TAYLOR R, 1993, NATURE, V363, P685 TAYLOR R, 1996, CHEM FULLERENS WAKAHARA T, 2002, J AM CHEM SOC, V124, P9465; NR: 57; TC: 5; J9: J ORG CHEM; PG: 8; GA: 721XFSource type: Electronic(1
Pseudo-outbreak of Pseudomonas putida Respiratory Infection Caused by Laboratory Contamination
No full textInternational audienc
Pseudo-outbreak of <i>Pseudomonas putida</i> Respiratory Infection Caused by Laboratory Contamination
No full textJ Hosp Infect
No full textCohorting carbapenemase-producing Enterobacteriaceae (CPE) carriers during hospitalisation limits the in hospital spreading. Our objective was to identify risk factors for CPE acquisition among contacts of an index patient in non-cohorted populations. A multicentre retrospective matched case-control study was conducted in five hospitals. Each contact patient (case) who acquired Klebsiella pneumoniae OXA-48 from an index patient was compared to three contact (controls) with the same index patients matched with hospitalization in the same unit and similar exposure-times. Fifty-one secondary cases and 131 controls were included. By univariate analysis exposure time (OR=1.06; 95% CI = 1.02 - 1.1; p = 0.006), concomitant infection at admission (OR=3.23; 95% CI = 1.42 - 7.35; p = 0.005), antimicrobial therapy within the last month before hospitalization (OR=2.88; 95% CI = 1.34- 6.2; p = 0.007), antimicrobial therapy during the exposure-time (OR=5.36; 95% CI = 2.28 - 12.6; p < 0.001), use of at least one invasive procedure (OR=2.99; 95% CI = 1.25 - 7.15; p = 0.014), number of invasive procedure (OR=1.52; 95%CI = 1.05 - 2.19; p=0.025), and the geographical proximity (OR=2.84; 95% CI = 1.15 - 7.00; p = 0.023) were associated with CPE acquisition. By multivariate analysis, antimicrobial therapy during the exposure-time (OR=6.36; 95% CI = 2.46 - 16.44; p < 0.001), at least one invasive procedure (OR=2.92; 95%CI=1.04-8.17; p=0.041), and geographical proximity (OR=3.69; 95% CI = 1.15 - 11.86; p = 0.028) were associated with acquisition. In this study, geographical proximity, invasive procedure and antimicrobial therapy during exposure-time were significantly associated with KP-OXA-48 acquisition
Impact of intensive care unit relocation and role of tap water on an outbreak of Pseudomonas aeruginosa expressing OprD-mediated resistance to imipenem
No full textBackground: To assess the impact of the incidental relocation of an intensive care unit (ICU) on the risk of colonizations/infections with Pseudomonas aeruginosa exhibiting OprD-mediated resistance to imipenem (PA-OprD). Aim: The primary aim was to compare the proportion of PA-OprD among P. aeruginosa samples before and after an incidental relocation of the ICU. The role of tap water as a route of contamination for colonization/infection of patients with PA-OprD was assessed as a secondary aim. Methods: A single-centre, observational, before/after comparison study was conducted from October 2013 to October 2015. The ICU was relocated at the end of October 2014. All P. aeruginosa-positive samples isolated from patients hospitalized ≥48 h in the ICU were included. Tap water specimens were collected every three months in the ICU. PA-OprD strains isolated from patients and tap water were genotyped using pulse-field gel electrophoresis. Findings: A total of 139 clinical specimens of P. aeruginosa and 19 tap water samples were analysed. The proportion of PA-OprD strains decreased significantly from 31% to 7.7% after the relocation of the ICU (P = 0.004). All PA-OprD clinical specimens had a distinct genotype. Surprisingly, tap water was colonized with a single PA-OprD strain during both periods, but this single clone has never been isolated from clinical specimens. Conclusion: Relocation of the ICU was associated with a marked decrease in P. aeruginosa strains resistant to imipenem. The polyclonal character of PA-OprD strains isolated from patients and the absence of tap-water-to-patient contamination highlight the complexity of the environmental impact on the endogenous colonization/infection with P. aeruginosa.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
