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Biomedical subjects

D Riley

Publications and source records attributed to D Riley.

At least 73 records · Page 4Linked to original sources
PubMed2001

Evidence of New States Decaying into Xi(*)(c)pi.

Using 13.7 fb(-1) of data recorded by the CLEO detector at Cornell Electron Storage Ring, we report evidence of two new charmed baryons: one decaying into Xi(0')(c)pi(+) with the subsequent decay Xi(0')(c)-->Xi(0)(c)gamma, and its isospin partner decaying into Xi(+')(c)pi(-) followed by Xi(+')(c)-->Xi(+)(c)gamma. We measure the following mass differences for the two states: M(Xi(0)(c)gammapi(+))-M(Xi(0)(c)) = 318.2+/-1.3+/-2.9 MeV and M(Xi(+)(c)gammapi(-))-M(Xi(+)(c)) = 324.0+/-1.3+/-3.0 MeV. We interpret these new states as the J(P) = 1 / 2(-) Xi(c1) particles, the charmed-strange analogs of the Lambda(+)(c1)(2593).

Journal Article↗
PubMed2001

Observation of B --> phiK and B --> phiK*.

We have studied two-body charmless hadronic decays of B mesons into the final states straight phiK and phiK(*). Using 9.7 million B&Bmacr; pairs collected with the CLEO II detector, we observe the decays B- --> phiK- and B0--> phiK(*0) with the following branching fractions: B(B--->phiK-) = (5.5(+2.1)(-1.8)+/-0.6)x10(-6) and B(B0--> phiK(*0)) = (11.5(+4.5+1.8)(-3.7-1.7))x10(-6). We also see evidence for the decays B0-->phiK0 and B---> phiK(*-). However, since the statistical significance is not overwhelming for these modes, we determine upper limits of <12.3x10(-6) and <22.5x10(-6) ( 90% confidence level), respectively.

Journal Article↗
PubMed2001

Observation of the Omega(0)(c) Charmed Baryon at CLEO.

The CLEO experiment at the CESR collider has used 13.7 fb(-1) of data to search for the production of the Omega(0)(c) (css ground state) in e(+)e(-) collisions at square root of (s) approximately 10.6 GeV. The modes used to study the Omega(0)(c) are Omega(-)pi(+), Omega(-)pi(+)pi(0), Xi-K-pi(+)pi(+), Xi0K-pi(+), and Omega(-)pi(+)pi(+)pi(-). We observe a signal of 40.4+/-9.0(stat) events at a mass of 2694.6+/-2.6(stat)+/-1.9(syst) MeV/c(2), for all modes combined.

Journal Article↗
PubMed2001

Measurement of the relative branching fraction of upsilon(4S) to charged and neutral B-meson pairs.

We analyze 9.7x10(6) B_B pairs recorded with the CLEO detector to determine the production ratio of charged to neutral B-meson pairs produced at the Upsilon(4S) resonance. We measure the rates for B0-->J/psiK((*)0) and B+-->J/psiK((*)+) decays and use the world-average B-meson lifetime ratio to extract the relative widths f(+-) / f(00) = gamma(Upsilon(4S)-->B+B-) / gamma(Upsilon(4S)-->B0 B-0)) = 1.04+/-0.07(stat)+/-0.04(syst). With the assumption that f(+-)+f(00) = 1, we obtain f(00) = 0.49+/-0.02(stat)+/-0.01(syst) and f(+-) = 0.51+/-0.02(stat)+/-0.01(syst). This production ratio and its uncertainty apply to all exclusive B-meson branching fractions measured at the Upsilon(4S) resonance.

Journal Article↗
PubMed2001

Measurement of the lambda(+)(c) lifetime.

The Lambda+c lifetime is measured using 9.0 fb(-1) of e+e- annihilation data collected on or just below the Upsilon(4S) resonance with the CLEO II.V detector at CESR. Using an unbinned maximum likelihood fit, the Lambda+c lifetime is measured to be 179.6+/-6.9(stat)+/-4.4(syst) fs. The precision of this colliding beam measurement is comparable to other measurements, which are based on fixed-target experiments, with different systematic uncertainties.

Journal Article↗
PubMed2001

Homeopathy and conventional medicine: an outcomes study comparing effectiveness in a primary care setting.

BACKGROUND: Recent meta-analyses of randomized controlled trials in homeopathy have suggested that homeopathy is more than a placebo response. OBJECTIVE: Comparison of the effectiveness of homeopathy in primary care with conventional medicine in primary care for three commonly encountered clinical conditions. DESIGN: An international multicenter, prospective, observational study in a real world medical setting comparing the effectiveness of homeopathy with conventional medicine. PARTICIPANTS: Thirty (30) investigators with conventional medical licenses at six clinical sites in four countries enrolled 500 consecutive patients with at least one of the following three complaints: (1) upper respiratory tract complaints including allergies; (2) lower respiratory tract complaints including allergies; or (3) ear complaints. MAIN OUTCOME MEASURES: The primary outcomes criterion was the response to treatment, defined as cured or major improvement after 14 days of treatment. Secondary outcomes criteria were: (1) rate of recovery; (2) occurrence of adverse events; (3) patient satisfaction; and (4) length of consultation. RESULTS: Four hundred and fifty-six (456) patient visits were compared: 281 received homeopathy, 175 received conventional medicine. The response to treatment as measured by the primary outcomes criterion for patients receiving homeopathy was 82.6%, for conventional medicine it was 68%. Improvement in less than 1 day and in 1 to 3 days was noted in 67.3% of the group receiving homeopathy and in 56.6% of those receiving conventional medicine. The adverse events for those treated with conventional medicine was 22.3% versus 7.8% for those treated with homeopathy. Seventy-nine percent (79.0%) of patients treated with homeopathy were very satisfied and 65.1% of patients treated with conventional, medicine were very satisfied. In both treatment groups 60% of cases had consultations lasting between 5 and 15 minutes. CONCLUSIONS: Homeopathy appeared to be at least as effective as conventional medical care in the treatment of patients with the three conditions studied.

Adolescent↗
PubMed2000

Cleavage of focal adhesion kinase by different proteases during SRC-regulated transformation and apoptosis. Distinct roles for calpain and caspases.

Integrin-associated focal adhesion complexes provide the main adhesive links between the cellular actin cytoskeleton and the surrounding extracellular matrix. In vitro, cells utilize a complex temporal and spatially regulated mechanism of focal adhesion assembly and disassembly required for cell migration. Recent studies indicate that members of both calpain and caspase protease families can promote limited proteolytic cleavage of several components of focal adhesions leading to disassembly of these complexes. Such mechanisms that influence cell adhesion may be deregulated under pathological conditions characterized by increased cell motility, such as tumor invasion. v-Src-induced oncogenic transformation is associated with loss of focal adhesion structures and transition to a less adherent, more motile phenotype, while inactivating temperature-sensitive v-Src in serum-deprived transformed cells leads to detachment and apoptosis. In this report, we demonstrate that v-Src-induced disassembly of focal adhesions is accompanied by calpain-dependent proteolysis of focal adhesion kinase. Furthermore, inhibitors of calpain repress v-Src-induced focal adhesion disruption, loss of substrate adhesion, and cell migration. In contrast, focal adhesion loss during detachment and apoptosis induced after switching off temperature-sensitive v-Src in serum-deprived transformed cells is accompanied by caspase-mediated proteolysis of focal adhesion kinase. Thus, calpain and caspase differentially regulate focal adhesion turnover during Src-regulated cell transformation, motility, and apoptosis.

Animals↗
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↗