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Food grinding is an abnormal behavior in rodents and its influencing factors are unknown. Our study investigated the potential relationships between gut microbiota and food grinding in Brandt's voles ( Lasiopodomys brandtii (Radde, 1861)) by comparing the differences between groups with different degrees of food grinding. The strong food-grinding group showed more relative food ground, higher ratio of ground food to food consumption, and lower percentage of time spent in the central area. The structure of fecal microbiota community differed between the strong and weak food-grinding groups. Strong and weak food-grinding voles showed higher abundances of Alistipes and Aerococcus and Atopostipes, Paenalcaligenes, Un—s-Clostridiaceae bacterium GM1, and Streptococcus, respectively. Strong correlations between the food ground to consumption ratio and abundances of fecal microbiota were found in Streptococcus and Paenalcaligenes. Fecal acetate and isobutyrate contents were higher in strong food-grinding voles and positively correlated with relative ground food and food ground to consumption ratio. Our study suggests that gut microbiota and short-chain fatty acids may contribute to the regulation of food-grinding behavior.

A theoretical model for tunable Mach–Zehnder interferometers (TMZIs) constructed in a two-dimensional photonic crystal (2D PhC) is proposed. The 2D PhC consists of a square lattice of cylindric air holes in silicon. The TMZI includes two mirrors and two splitters. Light propagates between them employing a self-collimation effect. The two interferometer branches have different path lengths. Parts of the longer branch are infiltrated with a kind of liquid crystal (LC) with ordinary and extraordinary refractive indices 1.522 and 1.706, respectively. The transmission spectra at two TMZI output ports are in the shape of sinusoidal curves and have a uniform peak spacing 0.0017c/a in the frequency range from 0.26c/a to 0.27c/a. When the effective refractive index neff of the liquid crystal is increased from 1.522 to 1.706, the peaks shift to the lower frequencies over 0.0017c/a while the peak spacing is almost kept unchanged. Thus this TMZI can work as a tunable power splitter or an optical switch. For the central operating wavelength around 1550nm, its dimensions are only about tens of micron. Thus this device may be applied to photonic integrated circuits.

We report an LD-end-pumped linearly-polarized continuous-wave (CW) Nd:YAP laser operating at 1341.4 nm. Making use of the plane-concave resonator (T = 2.4%) and the plane-plane resonator (T = 2.6%), we obtain linearly-polarized laser radiation at 1341.4 nm with a power of 3.15 and 2.86 W and corresponding optical slope efficiency of 18.4 and 17.5%, respectively. The effect of the laser oscillation mode on the output is analyzed. An experiment on the intra-cavity frequency doubling with an LBO crystal has been performed, and a laser power of 431 mW in one direction at 670.7 nm was obtained.