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D Riley

Publications and source records attributed to D Riley.

At least 37 records · Page 2Linked to original sources
PubMed2000

Study of charmless hadronic B meson decays to pseudoscalar-vector final states.

We report results of searches for charmless hadronic B meson decays to pseudoscalar( pi(+/-), K+/-, pi(0), or K(0)(S))-vector( rho, K(*), or omega) final states. By using 9.7x10(6) BB pairs collected with the CLEO detector, we report the first observation of B(-)--->pi(-)rho(0), B(0)-->pi(+/-)rho(-/+), and B(-)-->pi(-)omega, which are expected to be dominated by hadronic b-->u transitions. The measured branching fractions are (10.4(+3.3)(-3.4)+/-2.1)x10(-6), (27.6(+8.4)(-7.4)+/-4.2)x10(-6), and (11.3(+3.3)(-2.9)+/-1. 4)x10(-6), respectively. Branching fraction upper limits are set for all of the other decay modes investigated.

Journal Article↗
PubMed2000

Modification of inflammatory response to implanted biomedical materials in vivo by surface bound superoxide dismutase mimics.

The healing response to implanted biomedical materials involves varying degrees and stages of inflammation and healing which in some cases leads to device failure. In this article, we describe synthetic methods and in vivo results of a novel surface treatment for biomedical materials involving covalent conjugation of a low molecular weight superoxide dismutase mimic (SODm), which imparts anti-inflammatory character to the material. SODm investigated in this study are a new class of anti-inflammatory drugs consisting of a Mn(II) complex of a macrocyclic polyamine ring that catalyze the dismutation of superoxide at rates equivalent to that of native enzyme. The SODms were covalently linked to small disks of ultra-high molecular weight polyethylene, poly(etherurethane urea), and tantalum metal at two concentrations and implanted in a subcutaneous rat implant model for 3, 7, 14, and 28 days. Histological examination of the implant tissue performed at 3 and 28 days revealed striking anti-inflammatory effects on both acute and chronic inflammatory responses. At 3 days, the formation of a neutrophil-rich acute inflammatory infiltrate seen in control implants was inhibited for all three materials treated with SODm. At 28 days, foreign body giant cell formation (number of FBGCs per field) and fibrous capsule formation (mean thickness of implant capsule) were also significantly inhibited over untreated control implants. A mechanism based on our current understanding of superoxide as an inflammatory mediator at implanted biomedical materials is proposed.

Animals↗
PubMed2000

X-Ray diffraction from a dense plasma

We report measurements of x-ray scattering cross sections for dense plasmas created by subjecting aluminum foils to strong laser-driven shocks. A narrow cone of quasimonochromatic x-rays at approximately 4.75 keV was used to probe the shocked part of the foil and scattered photons were detected with a CCD camera. The scattering cross section shows a clear peak, indicating diffraction from the plasma. Analysis and simulation of the data suggest that radiative heating and electron-ion energy exchange are important factors in the plasma production.

Journal Article↗
PubMed2000

Plausibility of homeopathy and conventional chemical therapy: the systemic memory resonance hypothesis.

The controversy surrounding clinical observations and double-blind studies on homeopathic treatments is lessened when modern dynamical systems analysis is applied to high-dilution therapies. The logic of recurrent feedback loops, which applies to all dynamical network systems, inexorably leads to the systemic memory hypothesis - that complex patterns of emergent information and energy are stored to various degrees in physical, chemical, and biological systems. The addition of resonance, a dynamic pattern recognition process, explains many classic observations using high-dilution therapies. The systemic memory resonance hypothesis potentially provides a plausible biophysical mechanism for explaining not only how high-dilution therapies contribute to healing, but by extension, how information and energy in low-dilution and chemical therapies contribute to healing as well.

Drug Therapy↗
PubMed2000

Soft-x-ray emission dynamics in picosecond laser-produced plasmas

Plasmas were generated by prepulse-free picosecond laser irradiation of solid targets consisting of five different fluorine salts. Picosecond-time-resolved x-ray spectroscopy of K-shell emission from H-like and He-like fluorine was performed to study the temporal evolution of plasma parameters including electron density and temperature. Measurements show that the fluorine line emission intensity reaches its maximum in a time comparable with the rise time of the laser pulse. This peak is then followed by a decay whose rate depends upon the atomic number of the alkali component of the target. Our measurements show clear evidence of radiation cooling effects in higher-Z targets.

Journal Article↗
PubMed2000

Why older age predicts lower acceptance of physician-assisted suicide.

BACKGROUND: Prior research has shown that older Americans have less accepting attitudes toward the legalization of physician-assisted suicide (PAS). OBJECTIVE: The current study tests nine explanations for why older Americans are less accepting of PAS. DESIGN: Survey questionnaires in two settings: a small rural community and an internal medicine clinic in western Wisconsin (n = 1,311). RESULTS: Overall, 57% of this sample supported legalization of PAS while 31% opposed and 12% were in the middle. Two of the nine factors significantly (and negatively) predicted attitudes toward PAS: religious beliefs and belief that life's transitions have value. One factor is shown to mediate the relationship between age and PAS. Older subjects' greater focus on religious beliefs was able to significantly explain their lower levels of acceptance of PAS, as compared to younger subjects. CONCLUSION: Findings from this study support other PAS studies, which indicate that most Americans support the legalization of PAS. More importantly, it clarifies the role of age--that is, age is not important in and of itself. Rather, it is important as a predictor of religious beliefs which in turn predict negative attitudes and unique influences on the thinking of American adults concerning the legalization of PAS.

Adolescent↗
PubMed2000

Health care in big cities--the McGill experience.

Big cities encounter problems which are peculiar to them: population mix, housing conditions, social structure, infrastructure including transport, etc, which manifest in hospitals. From the beginning of the 20th century, big cities have been served by many providers of hospital care. Common to most cities is the change in the principles and methods of care, e.g. home care, and the notion that traditional hospital services are no longer the only answer to the needs of the population of large cities. Over the last decade, plans and projects have been devised to address the problems of excessive bed capacity, insufficient and excessive specialised units and difficulties in administration of payment systems.

Academic Medical Centers↗
PubMed1999

Combining serial analysis of gene expression and array technologies to identify genes differentially expressed in breast cancer.

Several methods have been used recently to determine gene expression profiles of cell populations. Here we demonstrate the strength of combining two approaches, serial analysis of gene expression (SAGE) and DNA arrays, to help elucidate pathways in breast cancer progression by finding genes consistently expressed at different levels in primary breast cancers, metastatic breast cancers, and normal mammary epithelial cells. SAGE profiles of 21PT and 21MT, two well-characterized breast tumor cell lines, were compared with SAGE profiles of normal breast epithelial cells to identify differentially expressed genes. A subset of these candidates was then placed on an array and screened with clinical breast tumor samples to find genes and expressed sequence tags that are consistently expressed at different levels in diseased and normal tissues. In addition to finding the predicted overexpression of known breast cancer markers HER-2/neu and MUC-1, the powerful coupling of SAGE and DNA arrays resulted in the identification of genes and potential pathways not implicated previously in breast cancer. Moreover, these techniques also generated information about the differences and similarities of expression profiles in primary and metastatic breast tumors. Thus, combining SAGE and custom array technology allowed for the rapid identification and validation of the clinical relevance of many genes potentially involved in breast cancer progression. These differentially expressed genes may be useful as tumor markers and prognostic indicators and may be suitable targets for various forms of therapeutic intervention.

Biomarkers, Tumor↗
PubMed1999

Forecasting patient services: a 21st century vision of an academic health centre.

This article provides an overview of the development and implementation of the McGill University Health Centre model for forecasting patient services in the year 2004, and advice on how to apply the model. Critical success factors and case examples are highlighted. The insights provided will be of value to hospitals and other institutions that recognize the necessity of engaging in long-range planning and forecasting.

Academic Medical Centers↗
PubMed1999

Harm reduction: concepts and practice. A policy discussion paper.

This paper provides an overview of the context, definition, and key features of the harm reduction approach, and provides several examples of current programs in various countries. Both licit and illicit drugs are included in these illustrations. Some of the critical issues, and the strategies needed to advance harm reduction, are discussed. [Translations are provided in the International Abstracts Section of this issue.]

Canada↗
PubMed1999

Synthesis and antibacterial activities of novel 12-O-methylerythromycin A derivatives.

The novel erythromycin A derivatives: 9(S)-9-dihydro-12-O-methylerythromycin A (6) and 12-O-methyerythromycin A (3), have been prepared using a new synthetic approach. The critical step is the regioselective methylation of the 12-hydroxyl of the boron complex of 2',4"-O-bis(trimethylsilyl)-9(S)-9-dihydroerythromycin A (8), which has unprotected 6-, 9- and 11-hydroxyl groups. The antibacterial activities of these new derivatives were compared with those of erythromycin A (1), clarithromycin (2) and 9(S)-9-dihydroclarithromycin (5).

Anti-Bacterial Agents↗