708-4 Can the Results of SPECT Scintigraphy Safely Guide Clinical Management of Patients with Active CAD?

Myocardial perfusion scintigraphy is increasingly used to categorize risk in pts with known or a high likelihood of CAD. This strategy will only be cost-effective if: 1) cardiologists will largely reserve further testing such as angiography (angio) to high-risk subsets; and 2) it is shown that less severe patterns of abnormality can be safely managed medically. We previously reported angio rates after all 4, 162 SPECT studies (excluding those with angio within 90 days beforeSPECT) at our cardiology practice-based nuclear lab: 4% (69/1663) in pts with fixed defects only and/or no ischemia; 60% (682/1141) in pts with high-risk ischemia (2 of multivessel or LAD distribution ischemia and abnormal lung uptake); and 9% (123/1352) for pts with mild-moderate ischemia. In this study, we determined outcome of the 1229 pts with mild-moderate ischemia who did not have referral for angio. Patient characteristics: mean age 65 yrs; known CAD=1061 (86%); prior CABG=344; prior MI=575; prior PTCA=674; angina=592. Twenty-eight (2%) pts were lost to follow-up. The remainder were followed for a mean of 18 months. There were 22 hard events (MI=15; cardiac death=71) (1.8%) and 54 pts required PTCA or CABG (total event rate 6.3%). Mean time to any event was 13.2 months from SPECT. Freedom from hard events at 1 yr was 99% and at 2 yrs 97%. Freedom from any event was 97% at 1 yr and 91% at 2 yrs.Conclusions1) SPECT can be a highly effective strategy for selecting pts for angio; 2) Even in a self-referral setting angio is largely reserved for pts with high-risk scans; and 3) Pts with mildly-moderately abnormal scans can be treated safely with medical therapy and close follow-u

Effect of mucoprotein on the bond strength of resin composite to human dentin

The final publication is available at Springer via http://dx.doi.org/10.1007/s10266-011-0002-9.The purpose of this study was to test the bond strength and analyze the morphology of the dentin-adhesive interface of two etch and rinse and two self-etch adhesive systems with two kinds of artificial saliva (with and without 450 mg/L mucin) contamination under different conditions of decontaminating the interface. Bonded specimens were sectioned perpendicularly to the bonded surface in 1-mm thick slabs. These 1-mm thick slabs were remounted in acrylic blocks and sectioned in sticks perpendicular to the bonding interfaces with a 1-mm2 area. Nine specimens from each condition were tested after 24 h on a testing machine (Instron) at a speed of 0.5 mm/min for a total of 360 specimens. Mean and standard deviations of bond strength (MPa) were calculated. ANOVA showed significant differences as well as Fisher’s PLSD intervals (p < 0.05). The following values are the results for different groups: Control group 34–60 MPa, saliva without mucin 0–52 MPa, and saliva with mucin 0–57 MPa. Failure sites were mixed and adhesive failure was common for the low bond strength results. P&BNT with ideal conditions and following the manufacturer’s instructions (control) had the highest bond strengths and the dentin-adhesive interface exhibited an ideal morphology of etch-and-rinse system. SEM gave complementary visual evidence of the effect in the dentin/adhesive interface structure with some contaminated conditions compared with their respective control groups. This in vitro artificial saliva model with and without mucin showed that an organic component of saliva could increase or decrease the bond strength depending on the specific bonding agent and decontamination procedure

Bond strength of adhesives to dentin contaminated with smoker’s saliva

The final publication is available at Springer via http://dx.doi.org/10.1007/s10266-009-0109-4.The purpose of this study was to determine the effects of contamination with smoker’s and non-smoker’s saliva on the bond strength of resin composite to superficial dentin using different adhesive systems. The interfacial structure between the resin and dentin was evaluated for each treatment using environmental scanning electron microscopy (ESEM). Freshly extracted human molars were ground with 600-grit SiC paper to expose the superficial dentin. Adhesives [One-Up-Bond-F-Plus (OUFP) and Adper-Prompt-L-Pop (APLP)] and resin composite (TPH-Spectrum) were bonded to the dentin (n = 8/group, 180 total specimens) under five surface conditions: control (adhesive applied following manufacturers’ instructions); saliva, then 5-s air dry, then adhesive; adhesive, saliva, 5-s air dry; adhesive, saliva, 5-s water rinse, 5-s air dry (ASW group); and adhesive, saliva, 5-s water rinse, 5-s air dry, reapply adhesive (ASWA group). After storage in water at 37°C for 24 h, the specimens were debonded under tension at a speed of 0.5 mm/min. ESEM photomicrographs of the dentin/adhesive interfaces were taken. Mean bond strength ranged from 8.1 to 24.1 MPa. Fisher’s protected least significant difference (P = 0.05) intervals for critical adhesive, saliva, and surface condition differences were 1.3, 1.3, and 2.1 MPa, respectively. There were no significant differences in bond strength to dentin between contamination by smoker’s and non-smoker’s saliva, but bond strengths were significantly different between adhesive systems, with OUFP twice as strong as APLP under almost all conditions. After adhesive application and contamination with either smoker’s or nonsmoker’s saliva followed by washing and reapplication of the adhesive (ASWA group), the bond strength of both adhesive systems was the same as that of the control group

Structural characterization of low‐temperature molecular beam epitaxial In0.52Al0.48As/InP heterolayers

A systematic study of the structural quality and arsenic content of as‐grown In0.52Al0.48As/InP layers deposited on InP by molecular beam epitaxy at temperatures between 150 and 450 °C was performed using transmission electron microscopy and particle‐induced x‐ray emission. We found that the amount of As incorporated in the layers generally increases with decreasing growth temperature, with the crystalline quality of the layers being good at growth temperatures higher than 200 °C. At 150 °C, a large density of pyramidal defects is formed, the defects are related to the very large amount of excess As incorporated into the layer. The mechanisms leading to the formation of these defects are discussed. At 200 °C, however, the amount of excess As is lower than expected, and wavy streaks of diffuse scattering are seen in electron diffraction. It is shown that small ordered domains of the CuPt type on the group III atoms are responsible for these features.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70657/2/APPLAB-60-8-989-1.pd

Representational capacity of a set of independent neurons

The capacity with which a system of independent neuron-like units represents a given set of stimuli is studied by calculating the mutual information between the stimuli and the neural responses. Both discrete noiseless and continuous noisy neurons are analyzed. In both cases, the information grows monotonically with the number of neurons considered. Under the assumption that neurons are independent, the mutual information rises linearly from zero, and approaches exponentially its maximum value. We find the dependence of the initial slope on the number of stimuli and on the sparseness of the representation.Comment: 19 pages, 6 figures, Phys. Rev. E, vol 63, 11910 - 11924 (2000

The Common Factors of Grit, Hope, and Optimism Differentially Influence Suicide Resilience

No study to date has simultaneously examined the commonalities and unique aspects of positive psychological factors and whether these factors uniquely account for a reduction in suicide risk. Using a factor analytic approach, the current study examined the relationships between grit, hope, optimism, and their unique and overlapping relationships in predicting suicide ideation. Results of principle axis factor analysis demonstrated close relationships between these variables at both the construct and item level. Item-level analyses supported a five-factor solution (Stick-to-Itiveness, Poor Future, Consistency of Interest, Positive Future, and Poor Pathways). Four of the five factors (excluding Stick-to-Itiveness) were associated with suicide ideation. Additionally, results of a multiple regression analysis indicated that two of the five factors (Consistency of Interest and Positive Future) negatively predicted suicide ideation while Poor Future positively predicted suicide ideation. Implications regarding the interrelationships between grit, hope, and optimism with suicide ideation are discussed

Deep-ultraviolet cavity ringdown spectroscopy

The sensitive optical detection technique of cavity ringdown spectroscopy is extended to the wavelength range 197-204 nm. A novel design narrowband Fourier-transform-limited laser is used, and the technique is applied to gas-phase extinction measurements in CO2, SF6, and O-2. Further demonstration of the system capabilities is given in high-resolution recordings of the Schumann-Runge (0, 0), (1, 0), and (2, 0) bands in O-2. (C) 2004 Optical Society of America

Slogging and Stumbling Toward Social Justice in a Private Elementary School: The Complicated Case of St. Malachy

This case study examines St. Malachy, an urban Catholic elementary school primarily serving children traditionally marginalized by race, class, linguistic heritage, and disability. As a private school, St. Malachy serves the public good by recruiting and retaining such traditionally marginalized students. As empirical studies involving Catholic schools frequently juxtapose them with public schools, the author presents this examination from a different tack. Neither vilifying nor glorifying Catholic schooling, this study critically examines the pursuit of social justice in this school context. Data gathered through a 1-year study show that formal and informal leaders in St. Malachy adapted their governance, aggressively sought community resources, and focused their professional development to build the capacity to serve their increasingly pluralistic student population. The analysis confirms the deepening realization that striving toward social justice is a messy, contradictory, and complicated pursuit, and that schools in both public and private sectors are allies in this pursuit

Odor supported place cell model and goal navigation in rodents

Experiments with rodents demonstrate that visual cues play an important role in the control of hippocampal place cells and spatial navigation. Nevertheless, rats may also rely on auditory, olfactory and somatosensory stimuli for orientation. It is also known that rats can track odors or self-generated scent marks to find a food source. Here we model odor supported place cells by using a simple feed-forward network and analyze the impact of olfactory cues on place cell formation and spatial navigation. The obtained place cells are used to solve a goal navigation task by a novel mechanism based on self-marking by odor patches combined with a Q-learning algorithm. We also analyze the impact of place cell remapping on goal directed behavior when switching between two environments. We emphasize the importance of olfactory cues in place cell formation and show that the utility of environmental and self-generated olfactory cues, together with a mixed navigation strategy, improves goal directed navigation

The spike-timing-dependent learning rule to encode spatiotemporal patterns in a network of spiking neurons

We study associative memory neural networks based on the Hodgkin-Huxley type of spiking neurons. We introduce the spike-timing-dependent learning rule, in which the time window with the negative part as well as the positive part is used to describe the biologically plausible synaptic plasticity. The learning rule is applied to encode a number of periodical spatiotemporal patterns, which are successfully reproduced in the periodical firing pattern of spiking neurons in the process of memory retrieval. The global inhibition is incorporated into the model so as to induce the gamma oscillation. The occurrence of gamma oscillation turns out to give appropriate spike timings for memory retrieval of discrete type of spatiotemporal pattern. The theoretical analysis to elucidate the stationary properties of perfect retrieval state is conducted in the limit of an infinite number of neurons and shows the good agreement with the result of numerical simulations. The result of this analysis indicates that the presence of the negative and positive parts in the form of the time window contributes to reduce the size of crosstalk term, implying that the time window with the negative and positive parts is suitable to encode a number of spatiotemporal patterns. We draw some phase diagrams, in which we find various types of phase transitions with change of the intensity of global inhibition.Comment: Accepted for publication in Physical Review