PubMed Health⌕ Search

Biomedical subjects

R Everson

Publications and source records attributed to R Everson.

6 recordsLinked to original sources
PubMed2002

Comparison of a needle-free high-pressure injection system with needle-tipped injection of intracavernosal alprostadil for erectile dysfunction.

Patients identified from hospital records as using alprostadil injections for erectile dysfunction were invited to take part in this open crossover study. On alternate weeks eight patients were given intracavernosal needle injections and transdermal needle-free injection of alprostadil in a randomized order. Efficacy of injection and associated pain were assessed and compared for the two methods. Pain produced during injection was significantly greater with the needle-free system than with the needle-tipped injection whilst efficacy was significantly less. Bruising was reported in all except one patient following needle-free injection only. Patient ratings of the needle-free injector were significantly lower than ratings for needle-tipped alprostadil delivery and when asked to express a preference, every patient chose the needle-tipped injection over the needle-free device.

Adult↗
PubMed1999

Independent component analysis: A flexible nonlinearity and decorrelating manifold approach.

Independent component analysis (ICA) finds a linear transformation to variables that are maximally statistically independent. We examine ICA and algorithms for finding the best transformation from the point of view of maximizing the likelihood of the data. In particular, we discuss the way in which scaling of the unmixing matrix permits a "static" nonlinearity to adapt to various marginal densities. We demonstrate a new algorithm that uses generalized exponential functions to model the marginal densities and is able to separate densities with light tails. We characterize the manifold of decorrelating matrices and show that it lies along the ridges of high-likelihood unmixing matrices in the space of all unmixing matrices. We show how to find the optimum ICA matrix on the manifold of decorrelating matrices, and as an example we use the algorithm to find independent component basis vectors for an ensemble of portraits.

Algorithms↗
PubMed1997

Separating spatially distributed response to stimulation from background. I. Optical imaging.

We consider the problem of estimating a small stimulus-induced response to stimulation that is masked by a fluctuating background when measurements of the background in the absence of stimulation are available, as is common in optical imaging of the cortex and in many other experimental situations. Two related methods based on the Karhunen-Loève procedure are discussed. One seeks the function, an indicator function, that is most parallel to the response data and most orthogonal to the background data. The second removes the subspace spanned by the background from the response. Numerical investigations on simulated optical imaging data show that the first method is generally superior. Connections between the two methods and techniques for assessing the quality of the result are discussed.

Artifacts↗
PubMed1976

Cancer of the uterine corpus after hormonal treatment for breast cancer.

Among 45853 women in whom breast cancer was diagnosed after age forty-nine, from the series of the End Results Program of the National Cancer Institute, cancer of the uterine corpus subsequently developed in 203. The risk was greater among those women receiving hormones than in other treatment groups, and tended to rise with increasing interval from first treatment. One method of estimating an expected value indicated that the excess risk of corpus cancer in breast-cancer patients was restricted to those treated with hormones. Given the time period under study, it may be assumed that the hormones were primarily non-steroidal oestrogens.

Age Factors↗