Gas-phase ionic reactions: dynamics and mechanism of nucleophilic displacements     

ML Chabinyc  SL Craig  CK Regan  JI Brauman 《Science (New York, N.Y.)》1998,279(5358):1882-1886

Nucleophilic displacement reactions (the SN2 reaction) of ions in the gas phase are a prototypical reaction system that allows a study of dynamics, mechanisms, and structure-energy relations. This article reviews aspects of the kinetics (especially the applicability of statistical reaction rate theory), the relation of structure and reactivity, and the effects of small numbers of solvent molecules on the reaction and compares the behavior of the ionic reaction in the gas phase with that in solution.  相似文献   

Cambrian burgess shale animals replicated in clay minerals     

PJ Orr  DEG Briggs  SL Kearns 《Science (New York, N.Y.)》1998,281(5380):1173-1175

Although the evolutionary importance of the Burgess Shale is universally acknowledged, there is disagreement on the mode of preservation of the fossils after burial. Elemental mapping demonstrates that the relative abundance of elements varies between different anatomical features of the specimens. These differences reflect the compositions of the minerals that replicated the decaying organism, which were controlled by contrasts in tissue chemistry. Delicate morphological details are replicated in the elemental maps, showing that authigenic mineralization was fundamental to preserving these fossils, even though some organic remains are also present.  相似文献   

Acute paraplegia in a Thoroughbred racehorse after general anaesthesia     

SR RAIDAL  SL RAIDAL  RB RICHARDS  AV COSGRIFF  KJ ROSE 《Australian veterinary journal》1997,75(3):178-179

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Thalidomide pharmacokinetics in sheep     

SL Smith  P Singh  D Harding  D Lun  JP Chambers 《New Zealand veterinary journal》2016,64(4):238-242

AIM: To determine the half life (T_1/2), time taken to reach maximum plasma concentration (T_max) and maximum plasma concentration (C_max) of thalidomide in sheep following I/V, oral and topical treatment with a single dose of thalidomide.

METHOD: Three groups of 4–6-month-old ram lambs were treated with thalidomide dissolved in dimethylsulphoxide (DMSO). The first group (n=10) was treated I/V with 100?mg thalidomide in 2?mL DMSO; the second group (n=8) received 400?mg thalidomide in 2?mL DMSO orally, and the third group (n=8) had 400?mg thalidomide in 4?mL DMSO applied topically. Plasma samples were collected up to 36 hours after treatment, snap-frozen at ?80°C and analysed for concentrations of thalidomide using high performance liquid chromatography.

RESULTS: Following I/V administration, T_1/2 was 5.0 (SEM 0.4) hours, volume of distribution was 3,372.0 (SEM 244.3) mL/kg and clearance was 487.1 (SEM 46.1) mL/hour.kg. Topical application of 400?mg thalidomide did not increase plasma concentrations. Following oral administration, thalidomide bioavailability was 89%, with T_1/2, T_max, and C_max being 7.2 (SEM 0.8) hours, 3.0 (SEM 0.4) hours and 1,767.3 (SEM 178.1) ng/mL, respectively.

CONCLUSION: Topical administration using DMSO as a solvent did not increase concentrations of thalidomide in plasma. The mean pharmacokinetic parameters determined following oral treatment with 400?mg of thalidomide were similar to those reported in humans receiving a single 400?mg oral dose (T_1/2 7.3 hours; T_max 4.3 hours and C_max 2,820?ng/mL). There is potential for thalidomide to be used as a model for the treatment of chronic inflammatory conditions in sheep, such as Johne's disease, where tumour necrosis factor alpha plays a pathogenic role.  相似文献   

Bilateral Sertoli and Interstitial Cell Tumours in Abdominal Testes of a Goat with Polled Intersex Syndrome (PIS)     

IF Canisso  LL Coffee  K Ortved  SL Fubini  LV Monteagudo  DH Schlafer  RO Gilbert 《Reproduction in domestic animals》2014,49(6):e64-e69

An 8‐year‐old, mixed breed, polled goat was presented for evaluation of male‐like behaviour. Clinical findings included clitoromegaly, a heavily muscled neck, pronounced beard, and erect dorsal guard hairs, which are phenotypic characteristics commonly observed in intersex animals. Transrectal ultrasonography revealed the presence of two abdominal masses caudolateral to the uterine horns. Serum concentration of estradiol was elevated. Genetic evaluation was compatible with polled intersex syndrome defined by an XX karyotype without a Y chromosome or SRY gene. Based on gross and histologic evaluation, the abdominal masses were determined to be intra‐abdominal testes, each of which was effaced by Sertoli cell and interstitial (Leydig) cell tumours. The Sertoli cell tumours (SCTs) represented two unique histologic patterns. Regardless of pattern, neoplastic Sertoli cells were consistently lipid laden and positive for vimentin. Interstitial cell tumours (ICTs) were negative for vimentin. Clinical and histopathologic findings suggest that prolonged exposure to steroids secreted by neoplastic Sertoli cells contributed to virilization. In addition, results from immunohistochemistry indicated that vimentin may be a valuable immunodiagnostic tool for differentiation between interstitial and Sertoli cell tumours in goats.  相似文献   

Dermatoses caused by infestations of immature Ixodes spp. on dogs and cats in Sydney, Australia   总被引：1，自引：1，他引：0  

CG Baxter  LJ Vogelnest  SL Doggett 《Australian veterinary journal》2009,87(5):182-187

Infestations of larval and nymphal Ixodes spp. were identified in 16 dogs and 16 cats from several small animal clinics in Sydney. Cases occurred in late summer or autumn, peaking in February, and were seasonally recurrent in some individuals. Clinical signs of infestation included a papular dermatitis and irritation or pruritus that ranged from severe to mild or absent. The distribution of tick attachment tended to be cranial and ventral, with the face, legs, axillae and ventrum the most commonly affected sites. The estimated number of ticks in each infestation varied from less than 10 to more than 100. Basic morphological examination of ticks collected from affected animals was performed by attending veterinarians using light microscopy, and larvae and nymphs belonging to the Ixodes genus were identified. Ticks collected from 17 animals and submitted to the Department of Medical Entomology, Westmead Hospital were putatively identified as I. trichosuri (57%) and I. holocyclus (25%) larvae. Histopathological samples of attachment sites collected from three dogs and one cat were characterised by ticks attached in well-demarcated invaginations of the skin ('tick craters') associated with variable epidermal and/or dermal necrosis, focal eosinophilic intraspinous pustules, mild to marked eosinophilic and neutrophilic, superficial to deep, dermal perivascular to interstitial inflammation, and moderate to marked superficial dermal oedema and red cell extravasation. A range of topical acaricidal preparations, including fipronil and synthetic pyrethroids, were used for treatment.  相似文献   

Cervical diskospondylitis in two horses     

CM COLBOURNE  SL RAIDAL  JV YOVICH  JMcC HOWELL  JL RICHARDSON 《Australian veterinary journal》1997,75(7):477-479

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Assessment of Ram and Boar Spermatozoa during Cell-sorting by Flow Cytometry   总被引：1，自引：0，他引：1  

SL Catt  JK O'Brien  WMC Maxwell  G Evans 《Reproduction in domestic animals》1997,32(5):251-258

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Neural tube defects in four Shetland sheepdog puppies: clinical characterisation and computed tomography investigation     

ZM Thomas  JM Podadera  SL Donahoe  TSY Foo  L Weerakoon  H Mazrier 《Australian veterinary journal》2020,98(7):312-318

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Partially Molten Middle Crust Beneath Southern Tibet: Synthesis of Project INDEPTH Results   总被引：23，自引：0，他引：23  

KD Nelson  W Zhao  LD Brown  J Kuo  J Che  X Liu  SL Klemperer  Y Makovsky  R Meissner  J Mechie  R Kind  F Wenzel  J Ni  J Nabelek  C Leshou  H Tan  W Wei  AG Jones  J Booker  M Unsworth  WSF Kidd  M Hauck  D Alsdorf  A Ross  M Cogan  C Wu  E Sandvol  M Edwards 《Science (New York, N.Y.)》1996,274(5293):1684-1688

INDEPTH geophysical and geological observations imply that a partially molten midcrustal layer exists beneath southern Tibet. This partially molten layer has been produced by crustal thickening and behaves as a fluid on the time scale of Himalayan deformation. It is confined on the south by the structurally imbricated Indian crust underlying the Tethyan and High Himalaya and is underlain, apparently, by a stiff Indian mantle lid. The results suggest that during Neogene time the underthrusting Indian crust has acted as a plunger, displacing the molten middle crust to the north while at the same time contributing to this layer by melting and ductile flow. Viewed broadly, the Neogene evolution of the Himalaya is essentially a record of the southward extrusion of the partially molten middle crust underlying southern Tibet.  相似文献