Correlation of the glass transition temperature of plasticized PVC using a lattice fluid model

A model has been developed to estimate the glass transition temperature of polymer+plasticizer mixtures (up to 30 wt% plasticizer). The model is based on the Sanchez-Lacombe equation of state and the Gibbs-DiMarzio criterion, which states that the entropy of a mixture is zero at the glass transition. The polymers studied included polystyrene and poly(vinyl chloride). The plasticizers studied included a wide range of chemicals from methyl acetate to di-undecyl phthalate. The model qualitatively accounted for the effect of different plasticizers on the mixture glass transition temperature.     

Age-related deficits in mice performing working memory tasks in a water maze.

This study determined whether mice exhibit spatial working memory deficits with increased age. C57BL/6JNia mice of 3 different ages were tested in the Morris water maze with 2 protocols designed to assess immediate and delayed working memory abilities. Young mice required multiple trials in order to show improvements in the working memory task. Deficits in immediate working memory were detected in both 10- and 24- to 26-month-old mice. Reference memory deficits and declines in performance in the delayed working memory task were only seen in 24- to 26-month-olds. This increased susceptibility of immediate working memory processes to the aging process in mice may be related to their need for more rehearsal in the water maze than other species. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thoughts of agoraphobic people during scary tasks.

The authors examined the occurrence of theoretically derived patterns of thinking in 74 agoraphobic participants as they drove alone or tolerated an enclosed place. During the increasingly scary tasks in a behavioral test hierarchy, participants responded to a periodic beep by stating aloud what they were thinking at that moment, yielding more than 1,800 tape-recorded statements. Content analyses revealed that participants were mainly preoccupied with their current anxiety (expressed in 29% of the statements) and with their self-efficacy (15%). Despite participants' mounting feelings of anxiety, fewer than 1% of their statements expressed a thought of danger or an anticipation of future anxiety or panic. The rarity of danger thoughts poses an explanatory challenge for all cognitive theories of phobia and especially for the perceived danger theory of A. T. Beck (1976) and A. T. Beck, G. Emery, and R L. Greenberg (1985). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the Computation of Optical Flow using the 3-D Gabor Transform

The motion of brightness patterns in an image sequence (optical flow) is most intuitively considered as a spatiotemporal phenomenon. It has been shown, however, that motion has a characteristic signature in the spatiotemporal-frequency (Fourier) domain. This fact can be exploited for the computation of optical flow. However, for cases which involve a number of regions in a sequence with different motions, as in scenes with one or more objects moving against a stationary or moving background, the global nature of the Fourier transform makes it unsuitable for this task. The signatures of the different motions cannot be resolved in the Fourier domain, nor associated with their respective regions in the image sequence. Local frequency representations provide a means to address this problem. In this paper, we consider the application of a 3-D version of the widely used Gabor transform to the computation of optical flow.     

CD56+ NK lymphomas: clinicopathological features and prognosis

Dosing regimen is an important determinant of both drug cost and patient compliance. This retrospective analysis evaluated dosing regimens and drug acquisition costs for 101 patients identified from medical records in a large metropolitan hospital as having hypertension and/or benign prostatic hyperplasia and receiving alpha-blocker therapy with either doxazosin or terazosin. Although once-daily administration is generally recommended for both drugs, 25 (38%) of 66 patients receiving terazosin were treated twice daily compared with 6 (17%) of 35 patients treated twice daily with doxazosin. This difference was statistically significant. The average (mean +/- SD) daily treatment cost per patient for all individuals receiving terazosin during the period of the record review was $1.68 +/- 0.60. For patients treated with doxazosin, the average was $0.96 +/- 0.65-a highly statistically significant result. If all 66 patients receiving terazosin had been converted to doxazosin at the beginning of the study, annual savings would have been $17,345.00. These results demonstrate the importance of reviewing actual dosing regimens. The fact that doxazosin could be administered to a significantly higher percentage of patients once daily rather than twice daily substantially decreased its cost relative to terazosin. A once-daily treatment regimen may also enhance patient compliance, thereby improving the chances of therapeutic success.     

Individual differences in the subjective effects of the first cigarette of the day: A self-report method for studying tolerance.

Some smokers are more sensitive than others to the subjective effects of cigarettes, especially the first cigarette of the day. This report explored self-reported subjective effects to the first cigarette of the day and examined the extent to which heaviness of smoking and years smoking are associated with subjective effects. In 3 independent samples (ns?=?254, 116, 86), self-reports of light-headedness from the first cigarette of the day decreased with increasing heaviness of smoking and increasing number of years smoking, suggesting that differences in responses were due to differences in chronic tolerance. Because measures of the subjective effects of drugs are useful in the study of drug response variability, this self-report item on light-headedness should be included in further research on individual differences in the subjective effects of cigarette smoking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interphase precipitation reaction in HSLA steels

An in-depth study of the interphase precipitation reaction in model vanadium steels has shown that the reaction may not just be confined to HSLA steels, but may be part of a general class of banded microstructures which are common to both eutectoid and eutectic systems. A new mass transport theory has been developed in which the interphase precipitation reaction in Fe-C-V steels is treated as a generalized type of cooperative growth. In addition to predicting the spacings of sheets of interphase precipitates and the precipitate sizes in steels, this theory is providing new insights into the origin of banded structures occurring in eutectic systems at solid-liquid interface boundary velocities faster than those required for coupled growth, but slower than those required to produce the extended metastable solid solution.     

The Relative Influences of Ring Modes and Methyl Internal Rotation on the Cold Beam IVR of p-Fluorotoluene

Room temperature (300 K) experiments have earlier established that the replacement of a fluorine atom in p-difluorobenzene (pDFB) with a methyl group to make p-fluorotoluene (pFT) generates a qualitative difference in intramolecular vibrational redistribution (IVR) characteristics as seen in the S₁ states. Here we report S₁–S₀ fluorescence excitation and dispersed single vibronic level (SVL) fluorescence spectra that have been obtained for IVR comparisons in the cold (5 K) environment of supersonic expansions. As in the 300 K experiments, the cold beam S₁ vibrational energy threshold for IVR is substantially lower in pFT. The vibrational congestion in dispersed fluorescence that reveals extensive S₁ level interactions first appears after pumping an S₁ pFT level near 800 cm⁻¹. In contrast, congestion in pDFB spectra is still absent from levels with twice this energy. Attention is directed to the relative S₁ ring level structures as a potential contributor to the distinctive IVR behaviors. Dispersed fluorescence from the S₁ zero point levels and fluorescence excitation spectra are combined with published information about S₁ fundamentals to show that the S₁ vibrational level structures of the two molecules are as closely related as those of an isotopomer pair. It is argued that the small differences in S₁ fundamentals cannot be a principal contribution to the qualitative IVR differences.     

Perfectionism, perceived weight status, and bulimic symptoms: Two studies testing a diathesis-stress model.

Among a total of 890 women from 2 separate nonclinical samples (1 collected in 1982 on college undergraduates, n?=?435, and 1 collected in 1992 on women who were in college in 1982, n?=?455), the authors tested a diathesis-stress model of the interrelations of perfectionism, perceived weight status, and bulimic symptoms. The authors predicted and found that perfectionism served as a risk factor for bulimic symptoms for women who perceived themselves as overweight but did not serve as a risk factor for those who did not perceive themselves as overweight. Perceived weight activated perfectionism as a predictor of bulimic symptoms; actual weight did not serve the same role. These findings are discussed in the context of recent clinical and social psychological theory regarding development of bulimic symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)