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131.
132.
S De Marino M Iorizzi F Zollo L Minale CD Amsler BJ Baker JB McClintock 《Canadian Metallurgical Quarterly》1997,60(10):959-966
A total of 19 steroids, of which 13 steroidal oligoglycosides (nine new and four known) and six polyhydroxylated steroids (four new and two known), has been isolated from the Antarctic starfish Acodontaster conspicuus. The mixture is dominated by glycosides composed of steroidal aglycons having the hydroxyl groups typically disposed on one side of the tetracyclic nucleus, i.e., 3 beta,4 beta,6 alpha,8,15 beta-, with some having a sulfate at C-6, and differing in the side chains and/or in the disaccharide moieties that are usually attached at C-26, with some at C-28 and C-29. Those compounds are accompanied by minute amounts of glycosides with a delta 8(14)-double bond in the steroid, which is a structural feature not previously found among polyhydroxysteroids derived from starfish. Small amounts of six related unglycosidated polyhydroxysteroids and three higher-molecular-weight asterosaponins complete the composition of the mixture. The structures of the new compounds were determined by interpretation of their spectral data and by comparison with spectral data of known compounds. Eighteen of these compounds were evaluated for their ability to inhibit growth in Antarctic marine bacteria isolated from either the water column or the surfaces of benthic marine invertebrates. Of these compounds, 50% were active against at least one Antarctic marine bacterium. This suggests that these compounds may play an important role in deterring microbial fouling. 相似文献
133.
PJ Klingler SL Smith BJ Abendstein E Brenner RA Hinder 《Canadian Metallurgical Quarterly》1997,92(12):2295-2298
A case is reported of an elective appendectomy in a patient with known ingestion of a sharp foreign body. The metal drill bit was ingested unintentionally 3 months before presentation at our institution. Plain abdominal films demonstrated the foreign body in the right lower abdominal quadrant. Because the gold dental drill bit was sharp and thought to be lodged in the terminal ileum or cecum, an attempt was made to remove the object during colonoscopy. This attempt was unsuccessful because no drill bit could be detected in the colon or terminal ileum. A laparoscopic exploration was performed, and the foreign body was found to lie in the appendix, after bowel manipulation under fluoroscopic guidance and with direct laparoscopic visualization. A laparoscopic assisted appendectomy was performed. On pathologic examination the drill bit was embedded in the tip of the appendix with signs of intramucosal acute inflammation. Management and indication for surgery of foreign bodies in the appendix are discussed, and we review the related literature. This is the second reported case of a dental drill bit in the appendix causing appendicitis. 相似文献
134.
135.
KS Armour BJ Clatworthy AR Bean JE Wells AM Clarke 《Canadian Metallurgical Quarterly》1997,110(1057):462-465
AIMS: To establish trends in frequency of serious spinal cord injuries in rugby and rugby league over a 20 year period and to elucidate patterns of injury from retrospective analysis of cases admitted to New Zealand's two spinal injuries units. METHODS: A detailed survey of unit records with follow-up of selected patients; statistical analysis of data. RESULTS: During the 20 years 1976 to 1995, 119 rugby and 22 rugby league players (total 141) were admitted to New Zealand's two spinal injuries units suffering serious spinal injuries and 47 of these became permanently confined to wheelchairs. There was a steady increase in frequency throughout the period studied. Of the injuries 83% occurred in forwards and 17% in backs. In rugby it was the scrum which produced most injuries, and in rugby league it was the tackle. The early season month of April produced most spinal injuries. In the eighteen months since intense compulsory educational programmes on safety were introduced by the New Zealand Rugby Union there have been no serious spinal cord injuries from rugby scrums. CONCLUSION: Contrary to widespread belief, there has not been a decrease in spinal cord injuries in rugby following rule changes in the mid 1980s. The information produced by this retrospective study has been an effective educational platform to make rugby and rugby league safer. 相似文献
136.
BJ Daly D Berry JJ Fitzpatrick B Drew K Montgomery 《Canadian Metallurgical Quarterly》1997,45(5):209-214
Assisted suicide is an issue of great importance to nurses. This issue reflects our values and beliefs as a society, calls for a clear and precise response as a profession, and challenges individual nurses to think about their own moral views. The history of the debate and the compelling moral arguments on both sides attest to the complexity of the issue and also suggest that it will not soon be resolved. The current position of the profession, as expressed in the ANA Code for Nurses and a specific position statement, were reviewed. The dilemma faced by the individual nurse who perceives an obligation to adhere to the guidelines specified by his or her profession's code and yet whose conscience dictates an act in violation of this code has been discussed as an instance of conscientious objection. While this analysis has been necessarily brief, it was intended to illustrate the importance of being clear about one's personal moral views and equally clear about one's duty to fulfil the obligations stemming from the profession's public statements. It is essential that the profession continue to explore the moral issues involved in requests for assistance in dying and provide additional guidelines for practicing nurses, with sound rationale for the profession's position. 相似文献
137.
S Katragadda A Xie D Puleo JB Skatrud BJ Morgan 《Canadian Metallurgical Quarterly》1997,83(6):2048-2054
Obstructive and nonobstructive apneas elicit substantial increases in muscle sympathetic nerve activity and arterial pressure. The time course of change in these variables suggests a causal relationship; however, mechanical influences, such as release of negative intrathoracic pressure and reinflation of the lungs, are potential contributors to the arterial pressure rise. To test the hypothesis that apnea-induced pressor responses are neurally mediated, we measured arterial pressure (photoelectric plethysmography), muscle sympathetic nerve activity (peroneal microneurography), arterial O2 saturation (pulse oximeter), and end-tidal CO2 tension (gas analyzer) during sustained Mueller maneuvers, intermittent Mueller maneuvers, and simple breath holds in six healthy humans before, during, and after ganglionic blockade with trimethaphan (3-4 mg/min, titrated to produce complete disappearance of sympathetic bursts from the neurogram). Ganglionic blockade abolished the pressor responses to sustained and intermittent Mueller maneuvers (-4 +/- 1 vs. +15 +/- 3 and 0 +/- 2 vs. +15 +/- 5 mmHg) and breath holds (0 +/- 3 vs. +11 +/- 3, all P < 0.05). We conclude that the acute pressor response to obstructive and nonobstructive voluntary apnea is sympathetically mediated. 相似文献
138.
Shidong Li Michael S. Sellers Cemal Basaran Andrew J. Schultz David A. Kofke 《International journal of molecular sciences》2009,10(6):2798-2808
Volumetric strain can be divided into two parts: strain due to bond distance change and strain due to vacancy sources and sinks. In this paper, efforts are focused on studying the atomic lattice strain due to a vacancy in an FCC metal lattice with molecular dynamics simulation (MDS). The result has been compared with that from a continuum mechanics method. It is shown that using a continuum mechanics approach yields constitutive results similar to the ones obtained based purely on molecular dynamics considerations. 相似文献
139.
D Vaudry BJ Gonzalez M Basille Y Anouar A Fournier H Vaudry 《Canadian Metallurgical Quarterly》1998,84(3):801-812
A high density of pituitary adenylate cyclase-activating polypeptide (PACAP) receptors coupled to both adenylyl cyclase and phospholipase C is found in the external granule cell layer of the rat cerebellum during postnatal development. It has recently been reported that synthetic PACAP promotes cell survival and neurite outgrowth in immature granule cells. In the present study, we have investigated the transduction pathways that mediate the neurotrophic activity of PACAP in cultured granule cells from eight-day-old rat cerebellum. The effect of PACAP on cell survival was mimicked by dibutyryladenosine 3',5'-cyclic-monophosphate but not phorbol 12-myristate 13-acetate suggesting that only the adenylyl cyclase pathway is involved in the neurotrophic activity of PACAP. PACAP also induced a transient increase in c-fos messenger RNA level. The ability of PACAP to stimulate c-fos gene expression was mimicked by dibutyryladenosine 3',5'-cyclic-monophosphate but not phorbol 12-myristate 13-acetate. Similar effects of PACAP on granule cell survival were observed whether the cells were continuously incubated with PACAP for 48 h or only exposed to PACAP during 1 h. The protein kinase A inhibitor H89 significantly reduced the effect of PACAP on c-fos messenger RNA level whereas the specific protein kinase C inhibitor chelerythrine did not modify c-fos gene expression. These data indicate that the action of PACAP on cerebellar granule cell survival and c-fos gene expression are both mediated through the adenylyl cyclase/protein kinase A pathway. The observation that a short-term stimulation by PACAP can be converted into a long-lasting response indicates that the effect of the peptide on cell survival must involve immediate-early gene activation. The fact that a brief exposure to PACAP causes both c-fos gene expression and promotes cell survival strongly suggests that c-fos is involved in the trophic effect of PACAP on immature cerebellar granule cells. 相似文献
140.