8,916 research outputs found
R. Neubauer to Mr. Meredith (12 October 1962)
https://egrove.olemiss.edu/mercorr_pro/2146/thumbnail.jp
Fluorescein angiography compared to three-dimensional measurements by the retinal thickness analyzer in classic choroidal neovascularization
Purpose: To compare and correlate imaging of classic subfoveal choroidal neovascularization (CNV) with noninvasive 3-dimensional imaging by the retinal thickness analyzer (RTA) to conventional fluorescein angiography (FA). Methods: A total of 29 eyes of 29 consecutive patients with predominantly classic CNV eligible for photodynamic therapy underwent FA and RTA imaging. The FA dimensions of the CNV were measured independently by two graders. With the RTA, masked to FA the size of the CNV itself as imaged in 3-dimensional reconstruction, the size of significantly thickened retina overlying the CNV and the maximum retinal thickness were measured. Results: The mean diameter of the CNV determined from 3-dimensional RTA reconstructions showed an excellent correlation with measurements from FA (r = 0.91, p < 0.001). The area of retinal thickening was by a mean of 0.7 mm in diameter larger and correlated moderately well with the size of the CNV on FA (r = 0.65, p < 0.001). In contrast, there was no correlation between the absolute retinal thickness and the CNV size on FA. Conclusions: Noninvasive quantitative mapping of predominantly classic CNV by RTA is feasible and also allows 3-dimensional measurement of the lesion itself. The results correlate well with FA assessment but visualize different properties of the disease. Copyright (c) 2007 S. Karger AG, Basel
Hypervelocity dust particle impacts observed by the Giotto Magnetometer and Plasma Experiments
We report thirteen very short events in the magnetic field of the inner magnetic pileâup region of comet Halley observed by the Giotto magnetometer experiment together with simultaneous plasma data obtained by the Johnstone plasma analyzer and the ion mass spectrometer experiments. The events are due to dust impacts in the milligram range on the spacecraft at the relative velocity between the cemetery dust and the spacecraft of 68 km/sec. They are generally consistent with dust impact events derived from spacecraft attitude perturbations by the Giotto camera [Curdt and Keller, private communication]. Their characteristic shape generally involves a sudden decrease in magnetic field magnitude, a subsequent overshoot beyond initial field values and an asymptotic approach to the initial field somewhat reminiscent of the magnetic field signature after the AMPTE releases in the solar wind. These observations give a new way of analyzing ultraâfast dust particles incident on a spacecraft
Generalized Qualification and Qualification Levels for Spectral Regularization Methods
The concept of qualification for spectral regularization methods for inverse
ill-posed problems is strongly associated to the optimal order of convergence
of the regularization error. In this article, the definition of qualification
is extended and three different levels are introduced: weak, strong and
optimal. It is shown that the weak qualification extends the definition
introduced by Mathe and Pereverzev in 2003, mainly in the sense that the
functions associated to orders of convergence and source sets need not be the
same. It is shown that certain methods possessing infinite classical
qualification, e.g. truncated singular value decomposition (TSVD), Landweber's
method and Showalter's method, also have generalized qualification leading to
an optimal order of convergence of the regularization error. Sufficient
conditions for a SRM to have weak qualification are provided and necessary and
sufficient conditions for a given order of convergence to be strong or optimal
qualification are found. Examples of all three qualification levels are
provided and the relationships between them as well as with the classical
concept of qualification and the qualification introduced by Mathe and
Perevezev are shown. In particular, spectral regularization methods having
extended qualification in each one of the three levels and having zero or
infinite classical qualification are presented. Finally several implications of
this theory in the context of orders of convergence, converse results and
maximal source sets for inverse ill-posed problems, are shown.Comment: 20 pages, 1 figur
Concentric left ventricular remodeling and aortic stiffness: A comparison of obesity and hypertension
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The Role of Lymphadenectomy in Surgical Staging of Endometrial Cancer
Surgical staging, including lymph node sampling, for endometrial cancer was adopted by the
International Federation of Gynecology and Obstetrics (FIGO) in 1988 based on reports demonstrating
diagnostic and therapeutic advantages. This review focuses on the incidence of lymph node metastasis,
risk factors for lymph node involvement, the effect of lymph node metastasis on prognosis, the
therapeutic effect and diagnostic usefulness of lymphadenectomy, risks of lymph node dissection, and
future directions in surgical staging of endometrial cancer. Surgical staging identifies most patients with
extrauterine disease as well as uterine risk factors for recurrence, thereby allowing for a more informed
approach to postoperative adjuvant therapy. Lymphadenectomy as a part of surgical staging is not
required in patients assessed intraoperatively to be at low risk for lymph node metastasis (<2âcm grade
1 tumors with superficial myometrial invasion), however, a systematic lymph node dissection should be
performed in most other patients with endometrial cancer. In the future, molecular markers may be
useful to predict preoperatively tumor aggressiveness and lymph node metastasis. It is hoped that an
approach of surgical staging with selective lymph node dissection will improve survival and spare
patients additional surgical complications or unnecessary postoperative exposure to radiation and/or
chemotherapy
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