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排序方式: 共有104条查询结果,搜索用时 125 毫秒
41.
Shazza Rehman Zanyar Movasaghi Art T. Tucker Simon P. Joel Jawwad A. Darr Alexander V. Ruban Ihtesham U. Rehman 《Journal of Raman spectroscopy : JRS》2007,38(10):1345-1351
A relatively non‐destructive method employing Raman spectroscopy for the analysis of histopathological specimens is described. Raman spectroscopy has allowed qualitative analysis of the same specimen used for histopathological evaluation. Breast cancer tissues have been analysed to demonstrate the feasibility of the chemical changes taking place in the biological tissue, which can be identified precisely, and the results are reproducible. Raman analysis of tissue sections provides distinct spectra that can be used to distinguish between the nuclear grades of ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) of the breast. Sixty cases of breast carcinoma including DCIS and IDC and seven cases of normal breast tissues were studied employing the Raman spectroscopic technique. This study reports for the first time spectral differences between DCIS grades. It is concluded that Raman spectroscopy can objectively distinguish between DCIS and IDC grades and is non‐destructive and reproducible. It should become possible in future to use Raman spectroscopy as an informative and quantitative method suitable for classification of grades and diagnosis of breast carcinoma. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
42.
A minimally invasive approach was proposed to measure local blood perfusion rate in living tissues, based on the well-known
Pennes bioheat equation. The measuring probe consists of a heater covered with conductive epoxy and temperature sensor deposited
on the probe–tissue interface. By monitoring the probe–tissue interface’s temperature response before and after employing
the constant heat flux, the tissue blood perfusion rate can be obtained. A theoretical model was developed to describe the
measurement system. In vivo experiments were performed on the rabbit’s thighs to validate this method. At last, uncertainties
implied in the temperature measurement and voltage across the heater was evaluated. The results point out the way to improve
the accuracy of the present method and its appropriate application occasion. 相似文献
43.
This paper proposes a novel calibration technique based on combining support vector regression with a digital band pass (DBP) filter for the quantitative analysis of near‐infrared spectra. The efficacy of the proposed method is investigated and validated in the determination of glucose from near‐infrared spectra of a mixture composed of urea, triacetin and glucose. In this paper, the DBP filtering was implemented as a pre‐processing technique in the frequency domain as a Gaussian band pass filter and in the time domain as a Chebyshev filter. The grid‐search optimization method was used to optimize the filter parameters. The results demonstrate that utilization of the optimized DBP filters as a pre‐processing technique improved the performance of the predictive models. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
44.
钬激光辅助治疗的咽部微创手术 总被引:2,自引:0,他引:2
目的 :探讨用钬激光辅助的微创手段治疗解剖位置较深 ,但又有自然通道的咽部良性肿瘤。方法 :14例术前诊断为咽部良性肿瘤患者 ,其中包括血管瘤 ,神经纤维瘤 ,乳头状瘤 ,淋巴组织。借助手术显微镜和内窥镜充分暴露位置较深的咽部肿瘤 ,用钬激光治疗咽部良性肿瘤。用Davis张口器暴露患者口咽部 ,若肿瘤暴露完整 ,则进行显微镜下处理 ;若肿瘤只能暴露部分 ,则口咽部用显微镜下处理 ,鼻咽部在内窥镜下处理。显微镜下精确肿瘤的边缘 ,分辨血管的走向 ,用钬激光烧灼 ,剥离子钝性分离 ,逐渐将肿瘤与周围正常组织分离。将内窥镜置于右侧鼻腔 ,探及鼻咽部。将钬激光发射光纤头从左侧鼻腔置入鼻咽部 ,内窥镜明视下在肿瘤周围烧灼 ,用镰状刀切开已烧灼创面粘膜 ,迅速钳取部分肿瘤留送病理检测。再用激光烧灼止血。结果 :手术中由于暴露充分 ,出血量较少 ,良性肿瘤能完整切除 ,未复发。结论 :利用各种显微、内窥镜手段能将解剖深部组织充分暴露 ,同时结合钬激光等器械能很好地处理肿瘤周围血管 ,能有效地、创伤极小地治疗咽部良性肿瘤 相似文献
45.
Plant diseases often cause yield losses in agriculture worldwide. In mathematical ecology, the concept of the basic (or basal) reproduction number, R0, has received little attention in the scientific literature related to phytopathogen transmission in plants. The spread and magnitude of outbreaks, the rate of invasion and infectivity of the etiologic agent, the contact complexities occurring among parasite and host, and its susceptibility and period of infectiousness are very important factors for epidemiological models. These mathematical models, when applied in ecology, can help to understand the spread of infections from phytopathogens (or pests) to plant hosts as well as detect potential risks of contamination or outbreaks by using the basic reproduction number in effective control strategies. In this study, the Maclaurin series concepts on the Force of Infection were applied to derive R0 expressions from generic epidemiological SIR (Susceptible‐Infected‐Removed) models. Consequently, we were able to obtain these relations from three transmission‐infection model examples. Then, once the expression of Force of Infection is known from the “infectious” problem studied, it is possible to apply this technique to formulate the R0 relation and guide practicable strategies for dispersing invasive phytopathogen controls. 相似文献
46.
Pierre Aboulker Nick Brettell Frédéric Havet Dániel Marx Nicolas Trotignon 《Journal of Graph Theory》2017,85(4):814-838
A graph G has maximal local edge‐connectivity k if the maximum number of edge‐disjoint paths between every pair of distinct vertices x and y is at most k. We prove Brooks‐type theorems for k‐connected graphs with maximal local edge‐connectivity k, and for any graph with maximal local edge‐connectivity 3. We also consider several related graph classes defined by constraints on connectivity. In particular, we show that there is a polynomial‐time algorithm that, given a 3‐connected graph G with maximal local connectivity 3, outputs an optimal coloring for G. On the other hand, we prove, for , that k‐colorability is NP‐complete when restricted to minimally k‐connected graphs, and 3‐colorability is NP‐complete when restricted to ‐connected graphs with maximal local connectivity k. Finally, we consider a parameterization of k‐colorability based on the number of vertices of degree at least , and prove that, even when k is part of the input, the corresponding parameterized problem is FPT. 相似文献
47.
Five French pastels and a sanguine drawing dating from the 17th to the 20th century were studied by Raman spectroscopy. Different operative conditions were used: the pastels were investigated through their protective glass, and the results obtained were compared with those obtained after removing the glass and after sampling a micrometric particle of pigment. Different parameters (wavelengths, powers of excitation and objectives) were tested in order to assess the optimal procedure of analysis for this fragile work of art. The results obtained for black (carbons), yellow (chrome/cobalt yellow), red (lead oxide, vermillion, orpiment), brown (red lead and chrome yellow), blue (Prussian blue, lapis lazuli/ultramarine), green (mixture of above blue and yellow pigments) and white (calcite, lead white, anatase) pigments are presented and the consistency of the pigments' period of use with the dating proposed for each pastel is evaluated. In one of the pastels, the blackening of the carnation colour made of an unstable mixture of lead white, red lead and vermilion was studied. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
48.
49.
Martin Donnelley Kaye S. Morgan Andreas Fouras William Skinner Kentaro Uesugi Naoto Yagi Karen K. W. Siu David W. Parsons 《Journal of synchrotron radiation》2009,16(4):553-561
Fine non‐biological particles small enough to be suspended in the air are continually inhaled as we breathe. These particles deposit on airway surfaces where they are either cleared by airway defences or can remain and affect lung health. Pollutant particles from vehicles, building processes and mineral and industrial dusts have the potential to cause both immediate and delayed health problems. Because of their small size, it has not been possible to non‐invasively examine how individual particles deposit on live airways, or to consider how they behave on the airway surface after deposition. In this study, synchrotron phase‐contrast X‐ray imaging (PCXI) has been utilized to detect and monitor individual particle deposition. The in vitro detectability of a range of potentially respirable particulates was first determined. Of the particulates tested, only asbestos, quarry dust, fibreglass and galena (lead sulfate) were visible in vitro. These particulates were then examined after delivery into the nasal airway of live anaesthetized mice; all were detectable in vivo but each exhibited different surface appearances and behaviour along the airway surface. The two fibrous particulates appeared as agglomerations enveloped by fluid, while the non‐fibrous particulates were present as individual particles. Synchrotron PCXI provides the unique ability to non‐invasively detect and track deposition of individual particulates in live mouse airways. With further refinement of particulate sizing and delivery techniques, PCXI should provide a novel approach for live animal monitoring of airway particulates relevant to lung health. 相似文献
50.
This paper researched into some methods for generating min-weighted
rigid graphs and min-weighted persistent graphs. Rigidity and
persistence are currently used in various studies on coordination
and control of autonomous multi-agent formations. To minimize the
communication complexity of formations and reduce energy
consumption, this paper introduces the rigidity matrix and presents three
algorithms for generating min-weighted rigid and min-weighted
persistent graphs. First, the existence of a min-weighted rigid graph
is proved by using the rigidity matrix, and algorithm 1 is presented
to generate the min-weighted rigid graphs. Second, the algorithm 2
based on the rigidity matrix is presented to direct the edges of
min-weighted rigid graphs to generate min-weighted persistent
graphs. Third, the formations with range constraints are considered,
and algorithm 3 is presented to find whether a framework can form a
min-weighted persistent formation. Finally, some simulations are
given to show the efficiency of our research. 相似文献