Do Uric Acid Deposits in Zooxanthellae Function as Eye-Spots?

The symbiosis between zooxanthellae (dinoflagellate genus Symbiodinium) and corals is a fundamental basis of tropical marine ecosystems. However the physiological interactions of the hosts and symbionts are poorly understood. Recently, intracellular crystalline deposits in Symbiodinium were revealed to be uric acid functioning for nutrient storage. This is the first exploration of these enigmatic crystalline materials that had previously been misidentified as oxalic acid, providing new insights into the nutritional strategies of Symbiodinium in oligotrophic tropical waters. However, we believe these deposits also function as eye-spots on the basis of light and electron microscopic observations of motile cells of cultured Symbiodinium. The cells possessed crystalline deposit clusters in rows with each row 100–150 nm thick corresponding to 1/4 the wavelength of light and making them suitable for maximum wave interference and reflection of light. Crystalline clusters in cells observed with a light microscope strongly refracted and polarized light, and reflected or absorbed short wavelength light. The facts that purines, including uric acid, have been identified as the main constituents of light reflectors in many organisms, and that the photoreceptor protein, opsin, was detected in our Symbiodinium strain, support the idea that uric acid deposits in Symbiodinium motile cells may function as a component of an eye-spot

Weathering of the Granite Soils and Its Influence on the Stability of Slope

The cutting slopes in granite soil regions are exposed in air and subjected to temperature change and water infiltration immediately after cutting. Then the strength of the soil mass is lowered successively up to failure point. In order to clarify the cause of the phenomena, the authors tried to examine a slope selected in a granite soil region by means of physical, chemical and mineralogical analysis. According to the results obtained from the above experiments, it is concluded that the original ground before cutting can be classified into three zones with characteristic clay minerals and the more the ground is weathered initially, the more rapidly their strength decreases excepting for the severely weathered part. These results are considered to depend largely on the fact that the soil grains weathered originally in the long period of time are relatively sensitive or unstable to chemical and mechanical actions

A System Utilizing Metal Hydride Actuators to Achieve Passive Motion of Toe Joints for Prevention of Pressure Ulcers: A Pilot Study

This paper describes the influence of human toe movement on blood flow and the design of a toe joint passive motion system for preventing pressure ulcers. First, we measured lower extremity blood flow in the foot during active and passive motion of the toe to facilitate the design of new rehabilitation equipment. Also, the flexion and extension angles and the force of the toe joints were measured to determine appropriate specifications for the system. Increases in blood flow were observed at the external malleolus during movement. Flexion and extension angles and the force of the toe joints were found to differ significantly among participants. It is shown that a toe joint passive motion system can be effective in preventing pressure ulcers. On the basis of these results, a device using alloys of metal hydride (MH) as an actuator that is suitable for the system to initiate toe motion, was developed

Effect of purification method of β-chitin from squid pen on the properties of β-chitin nanofibers

Published online 20 June 2016The relationship between purification methods of β-chitin from squid pen and the physicochemical properties of β-chitin nanofibers (NFs) were investigated. Two types of β-chitin were prepared, with β-chitin (a → b) subjected to acid treatment for decalcification and then base treatment for deproteinization, while β-chitin (b → a) was treated in the opposite order. These β-chitins were disintegrated into NFs using wet pulverization. The β-chitin (b → a) NF dispersion has higher transmittance and viscosity than the β-chitin (a → b) NF dispersion. For the first time, we succeeded in obtaining 3D images of the β-chitin NF dispersion in water by using quick-freeze deep-etch replication with high-angle annular dark field scanning transmission electron microscopy. The β-chitin (b → a) NF dispersion has a denser and more uniform 3D network structure than the β-chitin (a → b) NF dispersion. Widths of the β-chitin (a → b) and (b → a) NFs were approximately 8–25 and 3–10 nm, respectively.ArticleINTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES. 91:987-993 (2016)journal articl

Validating Variational Bayes Linear Regression Method With Multi-Central Datasets.

PurposeTo validate the prediction accuracy of variational Bayes linear regression (VBLR) with two datasets external to the training dataset.MethodThe training dataset consisted of 7268 eyes of 4278 subjects from the University of Tokyo Hospital. The Japanese Archive of Multicentral Databases in Glaucoma (JAMDIG) dataset consisted of 271 eyes of 177 patients, and the Diagnostic Innovations in Glaucoma Study (DIGS) dataset includes 248 eyes of 173 patients, which were used for validation. Prediction accuracy was compared between the VBLR and ordinary least squared linear regression (OLSLR). First, OLSLR and VBLR were carried out using total deviation (TD) values at each of the 52 test points from the second to fourth visual fields (VFs) (VF2-4) to 2nd to 10th VF (VF2-10) of each patient in JAMDIG and DIGS datasets, and the TD values of the 11th VF test were predicted every time. The predictive accuracy of each method was compared through the root mean squared error (RMSE) statistic.ResultsOLSLR RMSEs with the JAMDIG and DIGS datasets were between 31 and 4.3 dB, and between 19.5 and 3.9 dB. On the other hand, VBLR RMSEs with JAMDIG and DIGS datasets were between 5.0 and 3.7, and between 4.6 and 3.6 dB. There was statistically significant difference between VBLR and OLSLR for both datasets at every series (VF2-4 to VF2-10) (P < 0.01 for all tests). However, there was no statistically significant difference in VBLR RMSEs between JAMDIG and DIGS datasets at any series of VFs (VF2-2 to VF2-10) (P > 0.05).ConclusionsVBLR outperformed OLSLR to predict future VF progression, and the VBLR has a potential to be a helpful tool at clinical settings

Effect of acidity on the physicochemical properties of α- and β-chitin nanofibers

Published online 11 Apr 2017We have investigated whether acidity can be used to control the physicochemical properties of chitin nanofibers (ChNFs). In this study, we define acidity as the molar ratio of dissociated protons from the acid to the amino groups in the raw chitin powder. The effect of acidity on the physicochemical properties of α- and β-ChNFs was compared. The transmittance and viscosity of the β-ChNFs drastically and continuously increased with increasing acidity, while those of the α-ChNFs were not affected by acidity. These differences are because of the higher ability for cationization based on the more flexible crystal structure of β-chitin than α-chitin. In addition, the effect of the acid species on the transmittance of β-ChNFs was investigated. The transmittance of β-ChNFs can be expressed by the acidity regardless of the acid species, such as hydrochloric acid, phosphoric acid, and acetic acid. These results indicate that the acidity defined in this work is an effective parameter to define and control the physicochemical properties of ChNFs.ArticleINTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES. 102:358-366 (2017)journal articl

Weak antilocalization induced by Se substitution in layered BiCh2_2-based (Ch = S, Se) superconductors LaO1−x_{1-x}Fx_xBiS2−y_{2-y}Sey_y

We report transport properties for layered BiCh2-based (Ch = S, Se) superconductors LaO1-xFxBiS2-ySey (x = 0.2, 0.5, y = 0-1.05) and the observation of weak antilocalization (WAL). Electrical resistivity and Hall coefficients for the Se-poor samples increase with decreasing temperature. The increase becomes less pronounced with increasing Se concentration indicating a loss of insulating behavior. Interestingly, the moderately Se-substituted samples exhibit metallic behavior in the high-temperature region and a weak increase in the resistivity in the low-temperature regions, which indicates the existence of carrier localization. The heavily Se-substituted compounds show metallic behavior in the entire-temperature region. Sign changes of the Hall coefficients are observed for the x = 0.2 samples, which possibly is related to a charge-density wave (CDW). Magnetoresistance measurements indicate that WAL is realized in the heavily Se-substituted systems. The WAL behavior is weakened by the changes in F and Se concentrations. A crossover state of the WAL and WL emerges around the moderately F-doped and Se-free LaO0.8F0.2BiS2. The change of the resistivity behavior by the F and Se substitution clearly correlates to the difference of the magnetoconductance. Moreover, the localization regions of the WAL-WL crossover and weak WAL states are possibly associated with the CDW. We propose that the BiCh2-based system is a good platform for studying relationship between WAL, superconductivity, and electronic ordering because those states are tunable by element substitutions with bulk single crystals