Malignant lesions of the liver identified on T1- but not T2-weighted MR images at 1.5 T

The authors reviewed their 2 1/2-year experience with a magnetic resonance (MR) imaging protocol for a 1.5-T MR imager that included T2-weighted fat-suppressed spin-echo, T1-weighted breath-hold gradient-echo, and serial dynamic gadolinium-enhanced T1-weighted gradient-echo imaging to identify histologic types of malignant liver lesions more apparent on T1- than on T2-weighted images. MR images of 212 consecutive patients with malignant liver lesions were reviewed. T2-weighted, T1-weighted, and dynamic contrast-enhanced T1-weighted images were examined separately in a blinded fashion. Seven patients demonstrated liver lesions (lymphoma [two patients] and carcinoid, hepatocellular carcinoma, colon adenocarcinoma, transitional cell carcinoma, and melanoma [one patient each]) on T1-weighted images that were inconspicuous on T2-weighted images. In all cases, the lesions were most conspicuous on T1-weighted images obtained immediately after administration of contrast agent. Histologic confirmation was present for all seven patients. The consistent feature among these lesions was that they were hypovascular, due either to a fibrous stroma or to dense monoclonal cellularity. These results suggest that in some patients with hypovascular primary neoplasms, the lesions may be identified only on T1-weighted images, and that immediate postcontrast T1-weighted images are of particular value in demonstrating lesions.     

Process design for the production of a ceramic-like body from recycled waste glass

The influence of fabrication variables on the sintering behaviour of a ceramic-like body containing 90% recycled waste glass was inferred from measurements of some of the fired properties (moduli of rupture and elasticity, firing shrinkage, bulk density and porosity). Interpretation of these results in terms of viscous sintering theory indicates the relative influence on the sintering behaviour of factors such as particle size and distribution, clay binder content and plasticity, pressing pressure, heating/cooling rate, firing temperature and time, thus enabling the fabrication variables to be optimized. Comparison of the physical properties of the resulting glass-based bodies with those of commercial ceramic tile bodies indicates that the glass-based bodies are very comparable with the best ceramic tiles tested, and considerably better than several commercially-produced clay-based bodies.     

Thermal fluctuation of fine ferromagnetic particles

Fine ferromagnetic particles jump spontaneously from one locally stable state to another; they surmount intervening energy bartiers with the aid of thermal agitation. A theory of this phenomenon has as its primary goal the calculation of time constants. The elements of such a theory are presented. The emphasis is on calculations that require only elementary methods and on results that are simple enough to be easily applicable. The reader is assumed to be acquainted with the basic properties of ferromagnetic materials but not necessarily with Brownian-motion theory, on which the present theory is based.     

Attributions for negative life events and depression: The role of perceived control.

Although perceptions of control occupied a central role in the development of learned helplessness theory, recent helplessness research has not considered controllability judgments when relating attributions to depression. Supporting the importance of this construct, the research discussed in this article found evidence that judgments of control interact with other attributions in predicting depression. Specifically, in a prospective study of stress and well-being in adolescence, internal, stable, and global attributions for negative events attributed to uncontrollable causes were found to be positively related to increases in depression (as predicted by the reformulated helplessness theory), but internal and global attributions for negative events attributed to controllable causes were found to be inversely related to increases in depression. The discussion considers the implications of the findings for understanding the nature of the relation between attributions for naturally occurring life events and depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The growth and properties of Mn-doped single-crystal InP

Manganese has been studied as a new acceptor impurity in bulk InP. Large single crystals which possess the lowest hole concentrations yet reported, 3 × 10¹⁴ cm^?3, have been grown by the liquid encapsulated Czochralski pulling technique. This low carrier level is due to the low distribution coefficient for the electrically active manganese, k_active = 4 × 10^?3 and the high activation energy, 0.30 eV. In comparison, the acceptor commonly used to produce p-type material in InP, Zn, has a distribution coefficient of ≈1.0 which makes it especially difficult to achieve the low hole concentrations necessary for certain device applications. Optical absorption and photoluminescence data are also reported.     

Persistent repetition priming in picture naming and its dissociation from recognition memory.

The current experiments investigated the longevity of repetition priming and dissociations between different memory measures. Picture-naming latencies revealed robust repetition priming in four separate studies: Previously named pictures were named faster than new pictures. The magnitude of this naming facilitation was stable across 1 to 6 weeks. The apparent temporal invulnerability of repetition priming was in marked contrast to the decline in episodic recognition memory across 6 weeks, suggesting a dissociation between implicit and explicit memory. Additional evidence of this dissociation was observed within each session: Naming facilitation for repeated pictures occurred regardless of whether those particular pictures were consciously recognized. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measured and perceived colour on cathode ray tubes

A study is outlined which indicates that the application of traditional colorimetry to CRT displays is not totally adequate. The findings may be interpreted as indicating that the measured colours of CRT displays are always more saturated than the colours perceived by the human eye.     

Knowledge and beliefs regarding the consequences of cigarette smoking and their relationships to smoking status in a biracial sample.

198 men and 413 women responded to random telephone surveys in Fargo, North Dakota and Memphis, Tennessee. Each S was given the Smoking Attitudes Survey, which assesses generalized health beliefs and health-related problems associated with smoking. Ss' knowledge of smoking-associated diseases and diseases not associated with smoking was also assessed. Stepwise regression analysis of composite knowledge scores revealed 4 predictors of the health consequences of smoking: education, race, smoking status, and income. Smokers reported less knowledge and less concern about health consequences of smoking, were more likely to be male, and were more concerned about health consequences of cholesterol. The best predictor of smokers who had never attempted cessation was their greater concern over weight control, compared with smokers with a history of smoking-cessation attempts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of nitrogen doping on the growth and properties of plasma-enhanced chemical-vapor-deposited diamond-like-carbon films

Nitrogen-doped diamond-like carbon (DLC) or amorphous hydrogenated carbon (a-C:H) films were grown by plasma enhanced chemical vapor deposition using methane and nitrogen gases as precursors. The effects of nitrogen trifluoride (NF₃) on these nitrogen-doped DLC films were also investigated. The deposition rate decreases sharply with the addition of nitrogen in the absence of NFF₃ due to dilution, while it increases in the presence of NFF₃ due, presumably, to the reduction of activated hydrogen species by the fluorine radical (F϶. X-ray photoelectron spectra reveal a nitrogen concentration in the range of 9.3 to 13.8% in these DLC films with a C Is electron binding energy of 287-288 eV, indicating the diamond-like structure. Infrared spectra of DLC films indicate the presence of amino groups (N-H) and nitrile and/or isonitrile (C= N) groups giving strong evidence of sp carbon. Diamond like carbon films deposited in CHF₄ +NF₄ (with and without NFF₃) have a lower refractive index, a lower bulk resistivity, and a lower optical bandgap than films deposited using CHF₄ due to a lower hydrogen content in the films. Moreover, the bulk resistivity of these films decreases by over four orders of magnitude and the optical bandgap decreases from 2.65 eV to about 0.75 eV following annealing at a temperature of 500°C.