An immediate-extraction anterior single-tooth replacement utilizing a fiber-reinforced dual-component bridge

Replacement of a single anterior tooth is an extremely challenging procedure. Numerous objective and subjective factors must be evaluated by the interdisciplinary team in the determination of the appropriate restorative method. This article reviews the restorative options and describes an emerging treatment modality--the fiber-reinforced dual-component bridge--as the option selected in a case requiring an immediate extraction of the maxillary right central incisor. The pertinent technology, indications, contraindications, and current clinical technique of dual-component nonmetallic prostheses are examined.     

Binding of the recA protein of Escherichia coli to single- and double-stranded DNA

The recA protein of Escherichia coli binds both single- (SS) and double-stranded (DS) DNA; however, the optimal conditions differ for interaction with these DNA substrates. Binding of DS DNA by recA protein is pH dependent (optimum near pH 6.2) and requires a nucleoside triphosphate (ATP) and divalent cation. Substitution of the 5'-O-3'-thiotriphosphate (ATP(gamma S)) for ATP leads to formation of stable complexes of recA protein and DNA that dissociate very slowly. Formation of these complexes is extremely sensitive to ionic strength and pH. However, once formed, the complexes resist changes in pH and high salt concentrations. SS DNA binds to recA protein in the absence of a nucleoside triphosphate, but recA protein-SS DNA complexes are stabilized by ATP(gamma S). At high recA protein/DNA ratios (1 recA protein monomer/30 nucleotides), these complexes sediment in sucrose gradients as large protein-DNA aggregates. Although ATP(gamma S) blocks dissociation of recA protein from DNA, ATP stimulates the release of recA protein from SS DNA. Hydrolysis of the ATP is not required for dissociation since it is also enhanced by ADP and certain nucleoside triphosphates that are not hydrolyzed by recA protein. recA protein binds with different affinities to ribohomopolymers and deoxyhomopolymers. It preferentially binds polydeoxythymidylate and polydeoxycytidylate but does not bind short oligonucleotides, indicating that there is a minimum size requirement for the binding step. The recA protein exists as a heterogeneous aggregate at pH 7.5 and at low ionic strength. At pH 6.2 in the presence of Mg2+, the protein sediments homogeneously as a dimer. At pH 6.2, ATP or ATP(gamma S) promotes an oligomerization of the recA protein which can be observed as filamentous structures by electron microscopy. Oligomerization is not induced by UTP, a nucleoside triphosphate that is efficiently hydrolyzed by the recA protein, but fails to stimulate efficiently recA protein-promoted annealing and assimilation of single-stranded DNA.     

Thermal conductivity of additively colored MgO

The thermal conductivity of MgO additively colored in magnesium vapor has been measured in the temperature range 1–55 K. These measurements have been compared to the pure crystal thermal conductivity data. There is a “dip” in the thermal conductivity vs. temperature curve of the additively colored specimen near 20 K, where the thermal conductivity is depressed to one-fifth of the pure crystal value. The “dip” is attributed to resonant phonon scattering associated with quasilocalized modes of theF center. After UV irradiation, resulting in partialF →F ⁺ conversion, the thermal conductivity “dip” was found to be much weaker. The increase in thermal conductivity of the bleached sample is attributed to a relaxation of neighboring ions due to the different charge state of the defect. A successful fit to the thermal conductivity data has been made using the Debye model of solids and a defect scattering rate consisting of a resonance expression plus Rayleigh scattering term. A good fit can be made to the data of the bleached specimen by varying only the parameter associated with concentration ofF centers.     

"Longitudinal study of social class and defense preferences": Erratum.

Reports an error in the original article by A. Weinstock (Journal of Consulting Psychology, 1967[Oct], 31[5], 539-541). In this article, the author failed to mention that the study was done at the University of California Institute of Human Development and was supported in part by United States Public Health Service Grant MH 06238-02. (The following abstract of this article originally appeared in record 1967-16574-001.) Longitudinal data were used to assess the relationship between childhood social class and the development of particular defense mechanisms in adulthood. Childhood social class was correlated with ratings of defense mechanisms made when Ss were 30 yr. old. The results show that denial is negatively and projection and intellectualization are positively correlated with childhood social class. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Terrain Vague: Interactive Space and the Housescape

‘Only connect!’ Despite the proliferation of interactivity technologies for domestic spaces, current commercial models for the smart house remain focused on the supply of gizmos and multimedia flatscreens. What is the design potential for connectivity in the home? Mike Weinstock asks how interactive technologies might achieve a new level of topographical and environmental change and enhance the spaces in which we live. Copyright © 2005 John Wiley & Sons, Ltd.     

Approach to the patient with palpitations

Palpitations are a common complaint present in up to 16% of outpatients. They are nonspecific and in only 15% of patients do they correlate with a cardiac arrhythmia. The significance of palpitations is related to the presence or absence of underlying cardiac disease, the clinical setting in which palpitations occur, and the characteristics and severity of symptoms. This article presents a concise approach to the evaluation of the ambulatory patient with palpitations.     

Rejoinder to "A reply to Weinstock."

Replies to D. Ehrenfreund's (see PA, Vol. 51:Issue 5) remarks questioning the appropriateness of the adjusted percentage maintenance schedule recommended by Weinstock in a review of deprivation schedules. The previous recommendation is reaffirmed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electron-electron scattering in vanadium

Measurements have been made over a range from liquid helium to room temperature of the electrical resistivity of a single crystal of vanadium with a residual resistance ratio (RRR) of 1974, the highest ever reported. The data were analyzed in terms of electron-impurity scattering, electron-electron scattering, and electron-phonon interband and intraband scattering. We have obtained aT ² electron-electron scattering coefficient of (1.6±0.2)×10^–11 cm/K², in agreement with that obtained earlier in the same laboratory on a crystal with lower purity. Therefore, we conclude that electron-electron scattering does contribute measurably to the electrical resistivity of vanadium at low temperature.Supported in part by the U.S. Department of Energy.     

Identification of informal reasoning fallacies as a function of epistemological level, grade level, and cognitive ability.

Informal reasoning fallacies are violations of critical discussion norms. As epistemological understanding of knowledge justification appears to underlie the informal reasoning skills of argument construction and evaluation, it was hypothesized that adolescents with greater epistemological sophistication would be more able to identify informal reasoning fallacies. It was hypothesized that 11th graders would be more epistemologically sophisticated than 7th or 9th graders and, thus, would more likely identify fallacies. Students responded to questions regarding argument scenarios that did or did not contain fallacies. More 11th graders identified fallacies. Epistemological level predicted only identification of one type of fallacy that might be described as epistemological in nature. Cognitive ability also seemed to contribute to the increased ability with grade to identify fallacies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predictors of engaging in problem gambling treatment: Data from the West Virginia Problem Gamblers Help Network.

Gambling help-lines are an essential access point, or frontline resource, for treatment seeking. This study investigated treatment engagement after calling a gambling help-line. From 2000–2007 over 2,900 unique callers were offered an in-person assessment appointment. Logistic regression analyses assessed predictors of (a) accepting the referral to the in-person assessment appointment and (b) attending the in-person assessment appointment. Over 76% of callers accepted the referral and 55% of all callers attended the in-person assessment appointment. This treatment engagement rate is higher than typically found for other help-lines. Demographic factors and clinical factors such as gender, severity of gambling problems, amount of gambling debt, and coercion by legal and social networks predicted engagement in treatment. Programmatic factors such as offering an appointment within 72 hr also aided treatment engagement. Results suggest gambling help-lines can be a convenient and confidential way for many individuals with gambling problems to access gambling-specific treatment. Alternative services such as telephone counseling may be beneficial for those who do not engage in treatment. (PsycINFO Database Record (c) 2011 APA, all rights reserved)