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11.
Object segmentation in medical images is an actively investigated research area. Segmentation techniques are a valuable tool
in medical diagnostics for cancer tumours and cysts, for planning surgery operations and other medical treatment. In this
paper, a Monte Carlo algorithm for extracting lesion contours in ultrasound medical images is proposed. An efficient multiple
model particle filter for progressive contour growing (tracking) from a starting point is developed, accounting for convex,
non-circular forms of delineated contour areas. The driving idea of the proposed particle filter consists in the incorporation
of different image intensity inside and outside the contour into the filter likelihood function. The filter employs image
intensity gradients as measurements and requires information about four manually selected points: a seed point, a starting
point, arbitrarily selected on the contour, and two additional points, bounding the measurement formation area around the
contour. The filter performance is studied by segmenting contours from a number of real and simulated ultrasound medical images.
Accurate contour segmentation is achieved with the proposed approach in ultrasound images with a high level of speckle noise. 相似文献
12.
Richard Hood David K. Aspinwall Sein Leung Soo Andrew L. Mantle Donka Novovic 《CIRP Annals》2014,63(1):53-56
Slot milling is presented as a potential manufacturing route for aerospace component feature production when machining γ-TiAl intermetallic alloy Ti–45Al–2Mn–2Nb + 0.8 vol.% TiB2XD using 2 mm diameter AlTiN coated WC ball nose end milling cutters. When operating with flood cutting fluid at v = 88 m/min, f = 0.05 mm/tooth, d = 0.2 mm, maximum flank wear was ∼65 μm after 25 min. SEM micrographs of slot surfaces show re-deposited/adhered and smeared workpiece material to a length of ∼50 μm. Brittle fracture of the slot edges was restricted to <10 μm with sporadic top burr formation observed up to ∼20 μm. Cross sectional micrographs of the slot sidewalls showed bending of the lamellae limited to within 5 μm. 相似文献
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14.
M. A. Islam M. Novovic P. Bowen J. F. Knott 《Journal of Materials Engineering and Performance》2003,12(3):244-248
Phosphorus is a very common trace element that can segregate at prior austenite grain boundaries and/or carbide/matrix interfaces
of low alloy steels at high temperature (e.g., order of 500 °C) and adversely affect the fracture properties. This paper investigates
segregation of P during reversible temper embrittlement (96 h at 520 °C) of quenched and fully tempered 2.25Cr-1Mo steel by
Auger electron spectroscopy and describes the segregation mechanism. This paper also describes the effect of P segregation
on fracture resistance and fracture mode of unembrittled steels, respectively, by fracture toughness testing over a temperature
range of −196 °C to 20 °C and fractography in scanning electron microscopes. During temper embrittlement phosphorus segregation
has been attributed due to the mechanism of “carbide rejection”. This segregation caused a reduction in fracture toughness
values of the quenched and tempered steels at all test temperatures and an increase in the transition temperature. Phosphorus
segregation also changed the brittle fracture micromechanism of quenched and fully tempered samples from one of transgranular
cleavage to a mixed mode of fracture (transgranular cleavage and intergranular decohesion). The micromechanism of fracture
at temperatures from the upper shelf, however, remained almost unchanged. 相似文献
15.
Blint Barth Dvid K. Jsz Tamara Horvth Bence Barth Gergely Marti Gerda Strifler Gabriella Varga Lilla Sndor Domonkos Pernyi Szabolcs Tallsy Tibor Donka Pter Jvor Mihly Boros Petra Hartmann 《International journal of molecular sciences》2022,23(9)
Despite their clinical effectiveness, a growing body of evidence has shown that many classes of antibiotics lead to mitochondrial dysfunction. Ceftriaxone and Rifaximin are first choice perioperative antibiotics in gastrointestinal surgery targeting fundamental processes of intestinal bacteria; however, may also have negative consequences for the host cells. In this study, we investigated their direct effect on mitochondrial functions in vitro, together with their impact on ileum, colon and liver tissue. Additionally, their impact on the gastrointestinal microbiome was studied in vivo, in a rat model. Rifaximin significantly impaired the oxidative phosphorylation capacity (OxPhos) and leak respiration in the ileal mucosa, in line with increased oxidative tissue damage and histological changes following treatment. Ceftriaxone prophylaxis led to similar changes in the colon mucosa. The composition and diversity of bacterial communities differed extensively in response to antibiotic pre-treatment. However, the relative abundances of the toxin producing species were not increased. We have confirmed the harmful effects of prophylactic doses of Rifaximin and Ceftriaxone on the intestinal mucosa and that these effects were related to the mitochondrial dysfunction. These experiments raise awareness of mitochondrial side effects of these antibiotics that may be of clinical importance when evaluating their adverse effects on bowel mucosa. 相似文献