Estimation for fatigue limit reliability of a metal with inhomogeneities under stress ratio

In this paper, by using statistical characteristics of hardness in a small region and statistical characteristics of mechanical condition in a small region based on a defect size distribution and a certain stress which is applied to a defect, a quantitative prediction method for fatigue limit reliability of a metal with inhomogeneities is proposed. Also rotating bending and push–pull fatigue tests under R=-1 are carried out on quenched-tempered 0.5% carbon steels, whose average hardness is about H_V600. Comparing a predicted fatigue limit reliability with experimental data, the applicability of the present proposed method is examined and confirmed.     

Fast and robust training of a probabilistic latent semantic analysis model by the parallel learning and data segmentation

Probabilistic Latent Semantic Analysis （PLSA） is proven to be effective in the information retrieval and the speech recognition technique. In this paper, we modify the calculation procedure of estimation algorithm. It substantially reduces the memory requirements. And, parallelization approach enables making models in less time. Next, we examined data segmentation for PLSA adaptation. Most meetings have a number of topics. We divide the meeting automatically and fit PLSA models with them. The experiment showed recognition performance improvement.     

Regulation of Photochemical Energy Transfer Accompanied by Structural Changes in Thylakoid Membranes of Heat-Stressed Wheat

Photosystems of higher plants alleviate heat-induced damage in the presence of light under moderate stressed conditions; however, in the absence of light (i.e., in the dark), the same plants are damaged more easily. (Yamauchi and Kimura, 2011) We demonstrate that regulating photochemical energy transfer in heat-treated wheat at 40 °C with light contributed to heat tolerance of the photosystem. Chlorophyll fluorescence analysis using heat-stressed wheat seedlings in light showed increased non-photochemical quenching (NPQ) of chlorophyll fluorescence, which was due to thermal dissipation that was increased by state 1 to state 2 transition. Transmission electron microscopy revealed structural changes in thylakoid membranes, including unstacking of grana regions under heat stress in light. It was accompanied by the phosphorylation of thylakoid proteins such as D1 and D2 proteins and the light harvesting complex II proteins Lhcb1 and Lhcb2. These results suggest that heat stress at 40 °C in light induces state 1 to state 2 transition for the preferential excitation of photosystem I (PSI) by phosphorylating thylakoid proteins more strongly. Structural changes of thylakoid membrane also assist the remodeling of photosystems and regulation of energy distribution by transition toward state 2 probably contributes to plastoquione oxidation; thus, light-driven electrons flowing through PSI play a protective role against PSII damage under heat stress.     

A normal intensity level of psycho-physiological stress can benefit working memory performance at high load

In recent years, the effects of stress on adaptation and human performance have received considerable attention in medical literature and in occupational fields. In this study, we employed an acute psycho-physiological laboratory stressor, which is similar to real life stressful conditions and is capable of reliably eliciting the normal range of stress effects. The primary goal of the present study was to investigate whether the effect of stress on working memory performance depends on the number of images that need to be maintained (memory load), and the duration of the retention interval. By manipulating the number of images and the length of the retention interval of the modified Stenberg working memory test, we altered the task difficulty and examined the consequent effects on behavior. Twelve young students were submitted to a stressful condition one day and a control condition on another day. The stressor used included a physiological factor (socially evaluated cold pressor test) and a psychosocial factor (modified version of trier social stress test). The sympathetic nervous system and hypothalamic–pituitary–adrenal axis activation were assessed by heart rate and salivary cortisol. It was found that this procedure, which involves exposure to a normal intensity level of psycho-physiological stress, can demonstrate the beneficial effect of stress on reaction time without decreasing accuracy at high memory loads, but not at low memory loads.     

The use of poly (ε‐caprolactone) to enhance the mechanical strength of porous Si‐substituted carbonate apatite

Poly(ε‐caprolactone) (PCL)/silicon‐substituted carbonate apatite (Si‐CO3Ap) composite derived from the interconnected porous Si‐CO3Ap reinforced with molten PCL was prepared. PCL was used to improve the mechanical properties of a porous apatite by a simple polymer infiltration method, in which the molten PCL was deposited through the interconnected channel of porous Si‐CO3Ap. The PCL covered and penetrated into the pores of the Si‐CO3Ap to form an excellent physical interaction with Si‐CO3Ap leading to a significant increase in diametral tensile strength from 0.23 MPa to a maximum of 2.04 MPa. The Si‐CO3Ap/PCL composite has a porosity of about 50–60% and an interconnected porous structure, with pore sizes of 50–150 μm which are necessary for bone tissue formation. These results could pave the way for producing a porous, structured biocomposite which could be used for bone replacement. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effects of light intensity and water temperature on oxygen release from roots into water lettuce rhizosphere

The oxygen release rate into the rhizosphere by a floating aquatic plant-water lettuce-was determined under various light intensities (0.0-1.2x10(5)lx) and water temperatures (10-35 degrees C). The net specific oxygen release rate was expressed by a model equation comprising the gross oxygen release rate and the rhizosphere respiration terms. Experimental and simulated results show that the net specific oxygen release rate increased with light intensity up to the optimal value, but slight inhibition by higher light intensities was observed at 10-20 degrees C. With increased water temperature, the respiration rate became larger than the gross oxygen release rate. The maximum net specific oxygen release rate of 11.0-12.5mg-O(2)kg-wet(-1)h(-1) was obtained at the optimal condition of about 25 degrees C and 9.0x10(4)-1.1x10(5)lx. The net oxygen release rate was negligible at 35 degrees C at any light intensity because the respiration rate was much greater than the gross oxygen release rate into the rhizosphere.     

Optimization of bacterial plasmid transformation using nanomaterials based on the yoshida effect

With the help of sepiolite, a unique method for transforming DNA into bacteria, based on the Yoshida effect, has been developed recently. However, we confronted many problems when this newest method was tried. Only a few transformants could be obtained even when 100 ng of plasmid pET15b was used, and a successful result seemed difficult to repeat. To address this problem, we optimized the operating method and could achieve about 15,000 transformants using the same amount of plasmid, which could match the efficiency gained using the calcium chloride transformation method. Meanwhile, the results could also be reproduced well. In the same way, carbon nanotubes were used to attain more than 15,000 transformants in the same situation. Therefore, the transformation method could be extended to other nanomaterials. Meanwhile, compared with the mechanism previously reported, we verified quite a different principle for the mechanism responsible for such a transformation. In sum, this unique transformation can be developed to become the third widely-used transformation method in laboratories in addition to the chemical method and electroporation.