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891.
Fluoroscopy-based 3-D reconstruction of femoral bone cement: a new approach for revision total hip replacement 总被引:1,自引:0,他引:1
de la Fuente M Ohnsorge JA Schkommodau E Jetzki S Wirtz DC Radermacher K 《IEEE transactions on bio-medical engineering》2005,52(4):664-675
In revision total hip replacement the removal of the distal femoral bone cement can be a time consuming and risky operation due to the difficulty in determining the three-dimensional (3-D) boundary of the cement. We present a new approach to reconstruct the bone cement volume by using just a small number of calibrated multiplanar X-ray images. The modular system design allows the surgeon to react intraoperatively to problems arising during the individual situation. When encountering problems during conventional cement removal, the system can be used on demand to acquire a few calibrated X-ray images. After a semi-automatic segmentation and 3-D reconstruction of the cement with a deformable model, the system guides the surgeon through a free-hand navigated or robot-assisted cement removal. The experimental evaluation using plastic test implants cemented into anatomic specimen of human femoral bone has shown the potential of this method with a maximal error of 1.2 mm (0.5 mm RMS) for the distal cement based on just 4-5 multiplanar X-ray images. A first test of the complete system, comparing the 3-D-reconstruction with a computed tompgraphy data set, confirmed these results with a mean error about 1 mm. 相似文献
892.
Harinder P S Makkar Michael Blümmel Norbert K Borowy Klaus Becker 《Journal of the science of food and agriculture》1993,61(2):161-165
Abstract. A method for gravimetric determination of tannins based on binding with insoluble polyvinylpyrrolidone (PVP) is presented. The gravimetric method gives the absolute amount of tannins and avoids problems of standards associated with spectrophotometric methods. The method was applied to nine browse and tree leaves. The values obtained correlate significantly with tannins determined spectrophotometrically, protein precipitation capacities and protein precipitable phenotics. This method together with other tannin assays will be useful in nutritional studies. The present study also demonstrates the different behaviour of tannic acids from different commercial sources towards PVP suggesting the presence of different moieties in tannic acids from different commercial sources and even among batches from the same source thereby affecting the results obtained using the spectrophotometric methods. Use of well-defined tannic acid as a standard in spectrophotometric methods is suggested which will allow meaningful comparison of values obtained from different laboratories. 相似文献
893.
O'Sullivan Maureen; Ekman Paul; Friesen Wallace; Scherer Klaus R. 《Canadian Metallurgical Quarterly》1985,48(1):54
14 groups of undergraduates (2 for each of 7 conditions) made judgments based on separated channels (speech content, voice quality, face alone, and body alone) and judgments based on combined channels (speech, face plus speech, and face plus body plus speech). Ss observed (via videotape) and heard (via audiotape) the spontaneous behavior of 15 stimulus persons in 2 types of interview situations and rated various aspects of the behavior. In Study 1, criterion judgments were based on a task similar to answering a phone. In Study 2, they were similar to watching TV. In Study 3, a complete set of behavioral clues was the basis of the criterion judgments. Results show that correlations between separated and combined channels varied significantly, depending on the kind of behavior judged. Judgments of honestly described positive feelings based on nonverbal channels were highly correlated with judgments of the whole person, while most speech-content judgments were uncorrelated. Judgments of stimulus persons' lied-about negative feelings were less influenced by nonverbal behavior. Judgments based on content of what was said were most highly correlated with how the person making the statement was judged. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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896.
The Concentration-Controlled Recycle Reactor. The scope offered by the concentration-controlled recycle reactor for elucidatin the kinetics of heterogeneous gas reactions is presented in three contexts: identification of reaction networks; experimental design; and separate determination of changes of activity. Control strategies appropriate for the problem at hand are an essential prerequisite for the application of experimental strategies. In particular, long analysis cycles require appropriate modification of modern methods of control theory. Various model-based control concepts have been developed and tested by experiment and simulation. 相似文献
897.
Hodapp Robert M.; Young Kathryn T.; Algieri Marie; Minde Klaus 《Canadian Metallurgical Quarterly》1992,24(3):other1
Reports an error in "Maternal emotional reactions to the premature infant in the context of the family" by Robert M. Hodapp and Kathryn T. Young (Canadian Journal of Behavioural Science Revue canadienne des Sciences du comportement, 1992[Jan], Vol 24[1], 29-40). The authors of the article should be listed as Robert M. Hodapp, Yale University, Kathryn T. Young, Yale University, Marie Algieri, Hospital for Sick Children, and Klaus Minde, Montreal Children's Hospital. The two last names were inadvertendly omitted. (The following abstract of the original article appeared in record 1992-27071-001.) Examined maternal emotional reactions to the birth and early development of premature infants and whether such reactions are influenced by specific social support variables. 22 mothers of premature infants (aged 26–31 wks) were rated on 13 general psychological characteristics common to "maternal mourning reactions" of mothers of handicapped and at-risk children. Ss experienced relatively brief adverse reactions. The proposed 3-stage model of maternal mourning (i.e., shock; emotional disorganization; emotional organization) did not appear to characterize this sample. Ss with supportive spouses and close friends experienced less severe emotional reactions, as did Ss whose husbands were looking forward to becoming fathers. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Zusammenfassung Instabile Str?mungsvorg?nge in Axialverdichtern werden entsprechend ihrer periodischen Erscheinungsform in die rotierende
Abl?sung und das Pumpen klassifiziert. Sie verursachen kritische Betriebszust?nde mit extrem hohen dynamischen Belastungen
aller Baugruppen. Dies gilt insbesondere für Flugtriebwerksverdichter, deren stabiler Betrieb durch h?ufige Lastwechsel und
zus?tzlich auftretende Einlaufst?rung stark gef?hrdet ist. Gegenma?nahmen werden um so erfolgreicher sein, je besser die str?mungsmechanischen
Vorg?nge sowohl in der Entstehungsphase als auch w?hrend des instabilen Verdichterbetriebes verstanden werden. Experimentelle
Untersuchungen sind in vielen F?llen aufgrund des Risikos gro?er Materialsch?den nicht durchführbar, so da? theoretische Verfahren
zunehmende Bedeutung erlangen.
In der vorliegenden Arbeit wird ein Rechenmodell vorgestellt, mit dessen Hilfe die instation?ren str?mungsmechanischen Vorg?nge
simuliert werden k?nnen und das Aussagen über den Zusammenhang zwischen einigen Systemparametern und den instabilen Str?mungsph?nomenen
erm?glicht. Im Vordergrund steht hierbei die Darstellung der rotierenden Abl?sung und des Pumpvorgangs als eine gekoppelte
Instabilit?tsform. Ein einfaches Modell einer Verdichteranlage wird ausgew?hlt, bestehend aus dem Einlauf, einem einzelnen
Laufrad, dem Druckstutzen und einem Speicher mit Drosselvorrichtung, um diese Kopplung mit einem numerischen L?sungsverfahren
nachzuweisen. Es stellt die Str?mung als einen zweidimensionalen, instation?ren, kompressiblen Vorgang dar, wobei die Verlust-
und Umlenkkorrelationen des Laufrades sowie die übertragungsgleichungen des Speichers in den entsprechenden Randkoordinaten
berücksichtigt werden. Umfangsabh?ngige Totaldruckst?rungen werden in Form eines St?rgitterbeiwertes der Str?mung im Ansaugstutzen
überlagert. Die Entwicklung des periodisch instation?ren Str?mungsfeldes in Abh?ngigkeit vom Speichervolumen und der Drosselstellung
wird in ausgew?hlten Simulationsbeispielen diskutiert. Zur vollst?ndigen Auswertung der Stabilit?tsuntersuchung wird die Pumpfrequenz,
die Frequenz umlaufender Str?mungsinstabilit?ten und die Anzahl der Abl?sezellen herangezogen.
Herrn Professor Dr.-Ing.Wilhelm Dettmering zum 75. Geburtstag gewidmet 相似文献