Heritability of anxiety sensitivity: a twin study

OBJECTIVE: In attempting to explain the familial predisposition to panic disorder, most studies have focused on the heritability of physiologic characteristics (e.g., CO2 sensitivity). A heretofore unexplored possibility is that a psychological characteristic that predisposes to panic-anxiety sensitivity-might be inherited. In this study, the authors examined the heritability of anxiety sensitivity through use of a twin group. METHOD: Scores on the Anxiety Sensitivity Index were examined in a group of 179 monozygotic and 158 dizygotic twin pairs. Biometrical model fitting was conducted through use of standard statistical methods. RESULTS: Broad heritability estimate of the Anxiety Sensitivity Index as a unifactorial construct was 45%. Additive genetic effects and unique environmental effects emerged as the primary influences on anxiety sensitivity. There was no evidence of genetic discontinuity between normal and extreme scores on the Anxiety Sensitivity Index. CONCLUSIONS: This study suggests that one psychological risk factor for the development of panic disorder-anxiety sensitivity-may have a heritable component. As such, anxiety sensitivity should be considered in future research on the heritability of panic disorder.     

Electrospun three‐dimensional silk fibroin nanofibrous scaffold

Practical application to three‐dimensional (3‐D) tissue culture has been limited by the structural restriction of two‐dimensional (2‐D) nature of electrospun nanofiber mat. In this study, for constructing 3‐D nanofibrous structure as real 3‐D tissue engineering scaffold, we developed new fabrication process with silk fibroin (SF) by electrospinning and evaluated the features of this SF nanofiber scaffold (SFNS) through morphological and cell‐culture analyses. Foam type of the SFNS exhibited high porosity as well as large pores and its cell proliferation well occurred inside (inner spaces of pores), which makes this suitable for 3‐D cell‐culture scaffold. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of water‐contact on the roughness of patterned photoresist investigated by AFM analysis

The effect of water‐contact time on the roughness increment of patterned photoresist (AZ5214) was investigated by atomic force microscopy (AFM) analysis and the reason for the roughness increment was studied by the gravimetric experiment and the ellipsometry method. New method for calculating root‐mean‐square (RMS) line edge roughness from AFM data and the model of immersion lithography for experimentation were established. From the gravimetric experiments, it was confirmed that the diffusion of water into photoresist file is ruled my Fick's law. It was suggested that the amount of the roughness increment during rapid evaporation of water. As a result, the roughness of both the patterned line edge and the surface were proportioned in the root of water‐contact time at the initial time and it was the same as the results in previous gravimetric experiments. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2361–2365, 2007     

Zr K-edge XAS study on ZrO<Subscript>2</Subscript>-pillared aluminosilicate

The ZrO₂-pillared clay with high acidic property has been prepared by reacting 1 wt% colloidal suspension of Na⁺-montmorillonite with 1 N aqueous solution of ZrOCl₂·8H₂O and by subsequent heating. The evolution of local structure around zirconium of the intercalant stabilized in-between aluminosilicate layers upon intercalating, drying, and pillaring condition has been systematically studied by X-ray absorption spectroscopy, and compared to those of reference compounds such as ZrO₂, and ZrOCl₂ · 8H₂O and its 1 N aqueous solution. The intercalated zirconium species was identified as the Zr-tetramer, [Zr₄(OH)₁₄(H₂O)₁₀]²⁺, with an average molecular volume of 10 × 10 Å² and a thickness of 4.5 Å. Also it becomes more condensed upon drying and eventually transforms to a zirconium oxide pillar upon calcination.     

Effect of Acceptors on the Segregation of Donors in Niobium-Doped Barium Titanate Positive Temperature Coefficient Resistors

Small amounts of niobium (donor) doping in barium titanate (BaTiO₃) cause semiconductivity in this material. When the amount of niobium is increased slightly, the BaTiO₃ is converted back to an insulator. This phenomenon is attributed to donor segregation. Such an insulating material can recover its semiconductivity when specific amounts of acceptors are introduced. The space-charge segregation theory explains that such acceptors can prevent the segregation of donors. Impedance/modulus analysis of BaTiO₃ with a slightly increased niobium content and with no or a minimal amount of magnesium (acceptor) show a response of a third resistance–capacitance (RC) network, in addition to the two that have been thought to be caused by the grains and grain boundaries. The response of the third RC network is not observed at greater magnesium concentrations that give a recovery of the semiconductivity. This study suggests that acceptors can inhibit the donor segregation.     

Correlation of Microstructure and Hydrogen Delayed Fracture for 1GPa Steels

Automobile industry tries to reduce the weight of automobile using high-strength steels.However,the high-strength steels are highly susceptible to delayed-fracture caused by hydrogen embrittlement.With increasing the strength,hydrogen embrittlement is more sensitive to diffusible hydrogen.The mechanism of delayed-fracture and the relationship with the microstructure and alloying elements are still ambiguous.This study analyzed the effect of the size and the spheroidization rate for the carbides on hydrogen-induced delayed fracture for 1GPa TS steel.