Wyniki wyszukiwania - Biblioteka Nauki

1

Finite Element analysis for Edge-to-Edge Technique to Treat Post-Mitral Valve Repair Systolic Anterior Motion

100%

Zhong Q. , Zeng W. , Huang X. , Zhao X.

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tom Vol. 16, no. 4

3--12

EN

Systolic anterior motion of the mitral valve is an uncommon complication of mitral valve repair, which requires immediate supplementary surgical action. Edge-to-edge suture is considered as an effective technique to treat post-mitral valve repair systolic anterior motion by clinical researches. However, the fundamentals and quantitative analysis are vacant to validate the effectiveness of the additional edge-to-edge surgery to repair systolic anterior motion. In the present work, finite element models were developed to simulate a specific clinical surgery for patients with posterior leaflet prolapse, so as to analyze the edge-to-edge technique quantificationally. The simulated surgery procedure concluded several actions such as quadrangular resection, mitral annuloplasty and edge-to-edge suture. And the simulated results were compared with echocardiography and measurement data of the patients under the mitral valve surgery, which shows good agreement. The leaflets model with additional edge-to-edge suture has a shorter mismatch length than that of the model merely under quadrangular resection and mitral annuloplasty actions at systole, which assures a better coaptation status. The stress on the leaflets after edge-to-edge suture is lessened as well.

2

Determination of the average maintenance time of CNC machine tools based on type II failure correlation

88%

Shen G. , Zeng W. , Han C. , Liu P. , Zhang Y.

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2017

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tom Vol. 19, no. 4

604--614

EN

An average maintenance time calculation method based on components failure correlation analysis is proposed to revise the traditional system maintenance time. This paper focus on complex system type II fault correlation, using the Decision-making trial and evaluation laboratory / Interpretative structural model method to divide the fault level of components. And the copula connection function is introduced to calculation of failure rate function of failure correlation components. In addition, the system maintenance time model is established by synthesizing the failure rate function of each unit of the system. Moreover, the average maintenance time under the minimum number of failures is determined. This method shows that the minimum average maintenance time of the proposed system is more reasonable than the traditional one and provides the basis for system and component reliability design.

PL

W artykule zaproponowano metodę obliczania średniego czasu konserwacji, opartą na analizie korelacji uszkodzeń elementów składowych systemu. Metoda ta ma na celu rewizję tradycyjnego czasu konserwacji systemu. Głównym tematem pracy jest korelacja awarii typu II występujących w systemach złożonych. Elementy systemu podzielono ze względu na poziom uszkodzenia przy użyciu metody DEMATEL w połączeniu z interpretacyjnym modelowaniem strukturalnym. Funkcję intensywności skorelowanych uszkodzeń elementów systemu obliczono za pomocą funkcji łączącej (kopuły). Dodatkowo, opracowano model czasu konserwacji systemu poprzez syntezę funkcji intensywności uszkodzeń każdej jednostki systemu. Ponadto, określono średni czas konserwacji dla minimalnej liczby uszkodzeń. Metoda ta pokazuje, że minimalny średni czas konserwacji proponowanego systemu jest korzystniejszy niż tradycyjnie przyjęty i stanowi podstawę do projektowania niezawodności systemu i jego składowych.

3

A special connection between gamma delta T cells and natural antibodies?

88%

Born W. K. , Huang Y. , Zeng W. , Torres R. M. , O'Brien R. L.

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2016

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tom 64

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nr 6

4

Simultaneous determination of eleven alkaloids in Corydalis decumbens by HPLC with diode-array detection

75%

Gu G. H. , Yang D. J. , Wang S. Y. , Zeng W. , Wang W. , Yuan J. S.

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2017

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tom Vol. 29, no. 1

121--134

EN

A high-performance liquid chromatography—diode-array detection method was developed and validated to determine simultaneously eleven major alkaloids in Corydalis decumbens (Thunb.) Pers. The alkaloids detected were corlumidine, protopine, coptisine, tetrahydrojatrorrhizine, palmatine, berberine, sanguinarine, papaverine hydrochloride, tetrahydropalmatine, bicuculline, and corydaline. Chromatographic separation was achieved using a C-18 column with a mobile phase composed of A (0.2% acetic acid solution, adjusted with triethylamine to pH 5.0) and B (acetonitrile), with stepwise gradient elution. Ultraviolet diode-array detection was used; chromatograms were examined at the wavelength of 280 nm. The regression equations showed a good linear relationship between the peak area of each marker and concentration (r = 0.9994–0.9999). The recovery values ranged between 93.66% and 100.54%. The method was fully validated with respect to detection and quantification limits, precision, reproducibility, and accuracy. The described high-performance liquid chromatography (HPLC) method was successfully used for the differentiation and quantification of the eleven major alkaloids in C. decumbens (Thunb.) Pers. and can be considered an effective procedure for the analyses of this important class of natural compounds.