A Model of the Relationship Between Psychosocial Variables and Diurnal Cortisol Rhythm Under Chronic Stress by Using Structural Equations

By using structural equations, we investigated the effect of chronic stress on salivary cortisol rhythm and proposed a causal model of chronic stress by using psychosocial and physiological data. First, 111 healthy workers (48 males, 63 females) completed questionnaires on chronic stress and lifestyle habits. Then, they provided saliva samples and answered questionnaires that were prepared to assess their psychological states 5 times (on waking up and at 10:00, 11:40, 14:00, and 16:00) on workdays. Structural equation modeling (SEM) revealed that chronic stress and longer commuting time resulted in sleep irregularities and this disrupted the cortisol circadian rhythm. This suggests that chronic stress disrupts the cortisol circadian rhythm even in healthy individuals, and sleep regularity mediates the effect of chronic stress on the cortisol rhythm.

     

Image-based magnification calibration for electron microscope

Magnification calibration is a crucial task for the electron microscope to achieve accurate measurement of the target object. In general, magnification calibration is performed to obtain the correspondence between the scale of the electron microscope image and the actual size of the target object using the standard calibration samples. However, the current magnification calibration method mentioned above may include a maximum of 5 % scale error, since an alternative method has not yet been proposed. Addressing this problem, this paper proposes an image-based magnification calibration method for the electron microscope. The proposed method employs a multi-stage scale estimation approach using phase-based correspondence matching. Consider a sequence of microscope images of the same target object, where the image magnification is gradually increased so that the final image has a very large scale factor $S$ (e.g., $S=1\!,\!\!000$ ) with respect to the initial image. The problem considered in this paper is to estimate the overall scale factor $S$ of the given image sequence. The proposed scale estimation method provides a new methodology for high-accuracy magnification calibration of the electron microscope. This paper also proposes a quantitative performance evaluation method of scale estimation algorithms using Mandelbrot images which are precisely scale-controlled images. Experimental evaluation using Mandelbrot images shows that the proposed scale estimation algorithm can estimate the overall scale factor $S=1\!,\!\!000$ with approximately 0.1 % scale error. Also, a set of experiments using image sequences taken by an actual scanning transmission electron microscope (STEM) demonstrates that the proposed method is more effective for magnification calibration of a STEM compared with a conventional method.     

Crisscross addition polymerization of alkyl aldazines and 1,4-phenylene diisocyanate

Crisscross addition polymerization of alkyl aldazines (i.e., acetaldehyde azine, propionaldehyde azine, and butyraldehyde azine (BuAz)) and 1,4-phenylene diisocyanate (Ph(IC)₂) was investigated under various conditions. The crisscross addition polymerizations in pyridine yielded polymers in higher yields. The polymers obtained in the present study exhibited very limited solubilities and contained fractions insoluble in conventional organic solvents. However, since the BuAz/Ph(IC)₂ polymers obtained at 24 and 48 h were soluble in pyridine, the M_w values for these polymers were determined to be 2.2 × 10³ and 4.4 × 10³, respectively, by small angle X-ray scattering. These data indicated that molecular weights of the pyridine-insoluble polymers were as high as or close to 10⁴. IR, ¹H NMR, and MALDI-TOF-MS data confirmed the formation of linear polymers by crisscross addition polymerization. Thermogravimetric analyses indicated that the polymers were considerably decomposed in the region of 300-400 °C, but the polymers exhibited residual weights of 15-25% even at 500 °C. Differential scanning calorimetry data indicated that glass transition temperatures for the polymers were higher than the onset of decomposition presumably because of the rigid backbone.     

A specimen-drift-free EDX mapping system in a STEM for observing two-dimensional profiles of low dose elements in fine semiconductor devices

We developed a specimen-drift-free energy-dispersive X-ray (EDX) mapping system in a scanning transmission electron microscope (STEM) to improve the sensitivity and spatial resolution of EDX elemental mapping images. The amount of specimen drift was analysed from two STEM images before and after specimen drift by using the phase-correlation method, and was compensated for with an image-shift deflector of the STEM by the displacement of the scanning electron beam. We applied this system to observe the two-dimensional distribution of low dose arsenic in silicon semiconductor devices. The sensitivity of the elemental mapping was improved to several tenths atomic % for arsenic atoms while maintaining a spatial resolution of 2 nm.