Approximate calculation of leaky-mode loss coefficients for Ti-diffused LiNbO3waveguides

A hybrid-mode model is developed which allows analytical calculation of the leaky-mode loss coefficient in Ti-diffused LiNbO3waveguides. Field representations correspond to the approximation of geometrical optics. Hybrid-mode effective indexes are approximated utilizing the known anisotropy of LiNbO3. ForX- orY-cut waveguides the leaky mode is shown to be an extraordinary-like hybrid mode with a small ordinary field component which arises from extraordinary to ordinary power conversion at the abrupt index boundary. This ordinary index component is not bound by the graded index boundary, giving rise to the power loss. The theoretical dependence of the loss coefficient on propagation direction is in agreement with experiment.     

Some pitfalls in psychological theorizing.

"The purpose of this paper is to draw attention to certain examples of confusing psychological statements. These could be classified as involving circularity, lack of parsimony, and indefinite regress. It is hoped that pointing to these examples will lead to their avoidance… . Explanations must lie outside of the thing explained… . It seems to us that, before we invoke a new term, we are obligated to consider whether we are adding unnecessarily to an already unparsimonious state of affairs… . The mere fact that one uses a new term implies that there is a difference, and it seems to us this carries with it the obligation to make the difference explicit. What is particularly unfortunate is the fact that failure to do so is often associated with a disregard for the work of others on essentially the same problem… . A greater regard for parsimony would probably lead to unification rather than fragmentation of research findings." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of microspheres containing cytokine neutralizing antibodies in endotoxemia.

Albumin microspheres are efficient carriers for delivering therapeutic agents to macrophages. In response to endotoxin, macrophages release tumor necrosis factor alpha (TNF alpha) and interleukin-1-beta (IL-1 beta). Blocking the effects of TNF alpha and IL-1 beta decreased lethality due to endotoxin-induced shock. In this study, we compared the efficacy of the microsphere form of TNF alpha and/or IL-1 beta neutralizing antibodies (NAs) with the free form of TNF alpha and/or IL-1 beta NA in preventing lethality due to endotoxemia and evaluated the duration of blockade by the microsphere form of TNF alpha and/or IL-1 beta NA on endotoxin-induced cytokine release. The results indicate that the microsphere form of TNF alpha and/or IL-1 beta NA protected 80% of the rats from lethal endotoxemia, while none of the rats that received the free from of TNF beta and/or IL-1 beta NA survived longer than 48 hr. The microsphere form of TNF alpha and/or IL-1 beta NA attenuated endotoxin-induced cytokine release more potently than the free form of TNF alpha and/or IL-1 beta NA in vivo. In vitro, the microsphere form of TNF alpha and/or IL-1 beta NA blocked endotoxin-induced cytokine release for at least 24 hr. Higher efficacy of the microsphere form of NA in reducing mortality and blocking cytokine release makes it more therapeutically advantageous than the free form of NA in the treatment of lethal endotoxemia.     

Edible mushroom (Agaricus bisporus) lectin, which reversibly inhibits epithelial cell proliferation, blocks nuclear localization sequence-dependent nuclear protein import

The Galbeta1-3GalNAcalpha (TF antigen)-binding lectin (ABL) from the common edible mushroom (Agaricus bisporus) has a potent anti-proliferative effect without any apparent cytotoxicity. This unusual combination of properties prompted investigation of its mechanism of action. In contrast to soluble lectin, agarose-immobilized, and hence noninternalizable ABL had no effect on proliferation of HT29 colon cancer cells. Electron microscopy of HT29 cells incubated with fluorescein- and gold-conjugated ABL showed internalization of the lectin into endocytotic vesicles and multivesicular bodies. Confocal microscopy showed perinuclear accumulation of fluorescein isothiocyanate-conjugated lectin, which also inhibits HT29 cell proliferation, raising the possibility that the lectin might interfere with nuclear pore function. Transport of heat shock protein 70 into the nucleus in response to heat shock was blocked by preincubation of HT29 cells for 6 h with 40 micrograms/ml ABL. In digitonin-permeabilized cells, nuclear uptake of bovine albumin conjugated to a nuclear localization sequence (NLS)-containing peptide was also inhibited by a 15-min preincubation with 40-100 micrograms/ml ABL. In contrast, serum-stimulated nuclear translocation of mitogen-activated protein kinase, which is NLS-independent, was not affected by pretreatment of cells with the lectin. These results suggest that the anti-proliferative effect of ABL is likely to be a consequence of the lectin trafficking to the nuclear periphery, where it blocks NLS-dependent protein uptake into the nucleus.     

Does psi exist? Lack of replication of an anomalous process of information transfer.

D. J. Bern and C. Honorton (1994) recently presented in this journal a set of ganzfeld extrasensory perception (ESP) experiments conducted by C. Honorton that appeared to support the existence of a communication anomaly. In this article, the authors present a meta analysis of 30 ganzfeld ESP studies from 7 independent laboratories adhering to the same stringent methodological guidelines that C. Honorton followed. The studies failed to confirm his main effect of participants scoring above change on the ESP task, Souffer z?=?0.70, p?=?.24, one-tailed; M effect size (z/N1/2)?=?0.013, SD?=?0.23. The new studies included replication attempts of 3 out of 5 internal effects reported as statistically significant by D. J. Bern and C. Honorton. Only 1 was confirmed, and the authors found the D. J. Bern and C. Honorton were mistaken in describing the original effect as being statistically significant. The authors conclude that the ganzfeld technique does not at present offer a replicable method for producing ESP in the laboratory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Demonstrating specific cognitive deficits: A psychometric perspective.

Cognitive deficits associated with psychopathology often do not occur in isolation. Consequently, identifying a specific deficit in a disorder requires comparing the magnitude of group differences on theoretically relevant measures with those on control tasks measuring other constructs. L. J. Chapman and J. P. Chapman (1973) noted that common forms of such Group?×?Task interactions are theoretically ambiguous unless performance measures have comparable discriminating power. The principles of psychometric matching for discriminating power developed in the Chapmans' research program are reviewed, and both criticisms and alternative psychometric approaches are evaluated. Psychometric matching can be mindful of threats to the construct validity of measures and frequently remains methodologically necessary. Otherwise, interactions involving measures that vary in sensitivity to individual differences may be misinterpreted as evidence for specific deficits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

10-GHz power performance of a type II InP/GaAsSb DHBT

Type-II InP/GaAsSb double heterojunction bipolar transistors (DHBTs) were fabricated and microwave power performance was measured. For an InP collector thickness of 150 nm, the DHBTs show a current gain of 24, low offset voltages, and a BV/sub CEO/>6V. The 1.2/spl times/16 /spl mu/m/sup 2/ devices show f/sub T/=205GHz and f/sub MAX/=106GHz at J/sub C/=304 kA/cm/sup 2/. These devices delivered 12.6 dBm to the load at P/sub AVS/=3.3 dBm operating at 10 GHz, yielding a power-added efficiency of 41% and G/sub T/=9.3 dB.