The relation between immunity and health: Comment on Pennebaker, Kiecolt-Glaser, and Glaser.

Pennebaker, Kiecolt-Glaser, and Glaser (1988) recently presented data showing changes in health care visits and immunological functioning as a result of a brief experimental manipulation in which subjects disclosed past traumatic events. The authors did not fully discuss the apparent parallel changes that occurred as they were assessed by two dependent measures, symptom-related and immunologic, and the data, therefore, may have been misinterpreted. In this article, we discuss the findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memorability functions as an indicator of qualitative age differences in text recall.

An analysis in which the probability of text unit recall for older adults [p(Re|O)] is plotted as a function of this probability for the young [p(Re|Y)] is considered as one way to assess whether there are qualitative differences in text recall for young and old. The application of this relative memorability analysis to previously reported data dealing with the immediate recall of spoken sentences (Stine, Wingfield, & Poon, 1986) revealed that although older adults show qualitative recall similar to younger adults when informational density is low, they show less discrimination among text elements when informational density is increased. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for auditory temporal distinctiveness: Modality effects in order and frequency judgments.

Two new, long-lasting phenomena involving modality of stimulus presentation are documented. In one series of experiments we investigated effects of modality of presentation on order judgments. Order judgments for auditory words were more accurate than order judgments for visual words at both the beginning and the end of lists, and the auditory advantage increased with the temporal separation of the successive items. A second series of experiments investigated effects of modality on estimates of presentation frequency. Frequency estimates of repeated auditory words exceeded frequency estimates of repeated visual words. The auditory advantage increased with frequency of presentation, and this advantage was not affected by the retention interval. These various effects were taken as support for a temporal coding assumption, that auditory presentation produces a more accurate encoding of time of presentation than does visual presentation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Investigation of photoresist-specific optical proximity effect

Optical proximity effects arising from individual resist characteristics are investigated. The parameters studied are those used in photoresist exposure and development simulation using the SOLID and Prolith/2 programs. The optical proximity effect is found to be independent of the exposure parameters but greatly affected by the development process and is shown to be a function of the Mack parameter, n, which is related to the resist contrast, γ. Finally, in order to put this effect into perspective with other resist selection criteria, the development parameter, n, is also shown to be related to wall angle and depth-of-focus (DOF).

The results of this investigation will therefore enable the user to select the most appropriate photoresist for a specific application.     

Radiobiology of alpha particles. IV. Cell inactivation by alpha particles of energies 0.4-3.5 MeV

In this report the effectiveness of low-energy alpha particles in the range 0.4 to 3.5 MeV for cell killing is investigated. Four cell lines of different nuclear dimensions (AG1522, C3H 10T1/2, CHO-10B, and HS-23) are studied. Monte Carlo simulations are carried out to interpret the experimental results. They are presented as a function of dose to the nucleus, the total track length of alpha particles in the nucleus, and other parameters. It is found that the effectiveness of alpha particles for cell killing decreases with decreasing alpha-particle energy. The maximum RBE value is found to extend to LET values as high as 180 keV/microns. Although the LET might be the same, the effectiveness of alpha particles for cell killing is higher in the ascending part of the Bragg curve compared to descending part of the Bragg curve. The terminal tracks of alpha particles are observed to be less effective for cell killing.     

Low-threshold, high-power, 1.3-μm wavelength, InGaAsP-InPetched-facet folded-cavity surface-emitting lasers

A 1.3-μm wavelength, InGaAsP-InP folded-cavity, surface-emitting laser with CH₄-H₂ reactive ion-etched vertical and 45° angled facets was demonstrated for the first time. Continuous-wave threshold currents of 32 mA have been achieved, with >15 mW CW power for the surface-emitted light. These surface-emitting lasers with two dry-etched facets are suitable for wafer-level testing and for monolithic integration with other InP-based photonic devices     

Channel response to grade-control structures on Muddy Creek,Mississippi

Grade-control structures are commonly employed to prevent bed degradation and concomitant bank instability of channelized reaches of rivers. A study of a 20 km reach of a coastal plains stream was conducted in 1985 to determine the effects of 12 rock-lined grade-control structures that were installed between 1977 and 1983 prior to channel excavation. An Allowable Tractive Stress Method (TR.25) was used to determine the placement of grade-control structures, and the gradients between them, for a trapezoidal-shaped channel designed to convey the 1 year recurrence interval peak flow. The design was successful in preventing bed degradation and bank erosion over the period of observation. However, unpredicted channel responses have occurred. Aggradation is apparent between control structures, and a two-stage compound channel has formed as a consequence of berm development, especially in the lower, older subreach. In the lower subreach, the vegetated berms have constricted the cross-sectional area at the design discharge (99 m³ s^?1), and as a result, water-surface slope, shear stress, and unit-stream power have incresed. Bed material has become coarser and better sorted, which has increased shear intensity values. These unexpected changes are attributed to the lack of adequate consideration of the requirement for balance between sediment supply and transport in the TR.25 procedure; seven tributaries contribute sediment to the main channel of the study reach. It appears that the increased energy is utilized in bedload transport rather than channel erosion. This study demonstrates that the TR.25 method is too conservative if significant amounts of sediment are being supplied to the design channel. In such cases, adjustments in channel morphology will increase the energy to accommodate bedload transport.     

Mice deficient in both p53 and Rb develop tumors primarily of endocrine origin

To examine whether a cooperative role exists between inherited Rb and p53 deficiency in tumorigenesis, crosses were made between p53- and Rb-deficient mice and were monitored for subsequent tumor incidence and spectrum. Parental mice containing either Rb or p53 mutant alleles showed a predisposition for pituitary adenomas or lymphomas and sarcomas, respectively. Mice heterozygous for both Rb and p53 mutant alleles developed tumors of endocrine origin (medullary thyroid carcinomas, pancreatic islet cell carcinomas, and pituitary adenomas) in addition to lymphomas and sarcomas. Except for pituitary adenomas, these endocrine tumors were rarely seen in the parental p53 or Rb mutant mice. Mice deficient for both Rb and p53 showed a faster rate of tumor development than mice deficient only in Rb or p53. These results indicate that p53 and Rb do cooperate in the acceleration of tumorigenesis and in the development of endocrine tumor types.     

Characterization of DNA adducts formed by anti-benzo[g]chrysene 11,12-dihydrodiol 13,14-epoxide

The anti-11,12-dihydrodiol 13,14-epoxide of benzo[g]chrysene, a fjord-region-containing hydrocarbon, was found to react with DNA in vitro to yield, as the major product, an adduct in which the epoxide of the 11R, 12S, 13S, 14R enantiomer was opened trans by the amino group of deoxyadenosine. The structures of this adduct and other deoxyadenosine and deoxyguanosine adducts were established by spectroscopic methods. In reactions with deoxyguanylic acid, a product tentatively identified as a 7-substituted guanine was also detected. The mutagenic properties of this dihydrodiol epoxide in shuttle vector pSP189 showed that mutation at AT pairs accounted for 39% of base change mutations whereas chemical findings indicated that about 60% of adducts formed in calf thymus DNA involved adenines. Since calf thymus DNA is 56% AT and the target supF gene is 41% AT, the findings represent a fairly close relationship between adduct formation and mutagenic response. Overall, the chemical and mutagenic selectivities for the two purine bases in DNA were similar, though not identical, to those for the only other fjord-region-containing hydrocarbon studied in depth, i.e., benzo[c]phenanthrene. A major difference for these two hydrocarbon derivatives, however, is that benzo[c]phenanthrene dihydrodiol epoxides react to much higher extents (approximately 4-fold) with DNA than did the benzo[g]chrysene derivative.