In Vitro Fermentation of Oat Flours from Typical and High β-Glucan Oat Lines

Two publicly available oat (Avena sativa) lines, “Jim” and “Paul” (5.17 and 5.31% β-glucan, respectively), and one experimental oat line “N979” (7.70% β-glucan), were used to study the effect of β-glucan levels in oat flours during simulated in vitro digestion and fermentation with human fecal flora obtained from different individuals. The oat flours were digested by using human digestion enzymes and fermented by batch fermentation under anaerobic conditions for 24 h. The fermentation progress was monitored by measuring pH, total gas, and short-chain fatty acid (SCFA) production. Significant effects of β-glucan on the formation of gas and total SCFA were observed compared to the blank without substrate (P \u3c 0.05); however, there were no differences in pH changes, total gas, and total SCFA production among oat lines (P \u3e 0.05). Acetate, propionate, and butyrate were the main SCFA produced from digested oat flours during fermentation. More propionate and less acetate were produced from digested oat flours compared to lactulose. Different human fecal floras obtained from three healthy individuals had similar patterns in the change of pH and the production of gas during fermentation. Total SCFA after 24 h of fermentation were not different, but the formation rates of total SCFA differed between individuals. In vitro fermentation of digested oat flours with β-glucan could provide favorable environmental conditions for the colon and these findings, thus, will help in developing oat-based food products with desirable health benefits

Self-Assembled Charged Hydrogels Control the Alignment of Filamentous Actin

We demonstrate a novel route to control attachment of filamentous actin (F-actin) on hydrogel films. By incorporating an amine-terminated silane, the hydrogel surface charge and surface topography are varied. With increasing silane content, F-actin reorients from perpendicular to parallel to the hydrogel surface, ceases to wobble, and forms mainly elongated or cyclic structures. F-Actin coverage reaches a maximum at 2.5 vol% silane and declines at higher silane content. This biphasic behavior is explained by the simultaneous increase in surface charge and the self-assembly of a micron scale pattern of positively charged islands. Our approach provides guidelines for constructing nanoscale tracks to guide motor proteins underlying nano-engineered devices such as molecular shuttles

Spectral Density Scaling of Fluctuating Interfaces

Covariance matrix of heights measured relative to the average height of a growing self-affine surface in the steady state are investigated in the framework of random matrix theory. We show that the spectral density of the covariance matrix scales as $\rho(\lambda) \sim \lambda^{-\nu}$ deviating from the prediction of random matrix theory and has a scaling form, $\rho(\lambda, L) = \lambda^{-\nu} f(\lambda / L^{\phi})$ for the lateral system size $L$, where the scaling function $f(x)$ approaches a constant for $x \ll 1$ and zero for $x \gg 1$. The obtained values of exponents by numerical simulations are $\nu \approx 1.73$ and $\phi \approx 1.40$ for the Edward-Wilkinson class and $\nu \approx 1.64$ and $\phi \approx 1.79$ for the Kardar-Parisi-Zhang class, respectively. The distribution of the largest eigenvalues follows a scaling form as $\rho(\lambda_{max}, L) = 1/L^b f_{max} ((\lambda_{max} -L^a)/L^b)$, which is different from the Tracy-Widom distribution of random matrix theory while the exponents $a$ and $b$ are given by the same values for the two different classes

Dynamics of Helping Behavior and Networks in a Small World

To investigate an effect of social interaction on the bystanders' intervention in emergency situations a rescue model was introduced which includes the effects of the victim's acquaintance with bystanders and those among bystanders from a network perspective. This model reproduces the experimental result that the helping rate (success rate in our model) tends to decrease although the number of bystanders $k$ increases. And the interaction among homogeneous bystanders results in the emergence of hubs in a helping network. For more realistic consideration it is assumed that the agents are located on a one-dimensional lattice (ring), then the randomness $p \in [0,1]$ is introduced: the $kp$ random bystanders are randomly chosen from a whole population and the $k-kp$ near bystanders are chosen in the nearest order to the victim. We find that there appears another peak of the network density in the vicinity of $k=9$ and $p=0.3$ due to the cooperative and competitive interaction between the near and random bystanders.Comment: 13 pages, 8 figure

Two-gap and paramagnetic pair-breaking effects on upper critical field of SmFeAsO0.85_{0.85} and SmFeAsO0.8_{0.8}F0.2_{0.2} single crystals

We investigated the temperature dependence of the upper critical field [$H_{c2}(T)$] of fluorine-free SmFeAsO$_{0.85}$ and fluorine-doped SmFeAsO$_{0.8}$F$_{0.2}$ single crystals by measuring the resistive transition in low static magnetic fields and in pulsed fields up to 60 T. Both crystals show that $H_{c2}(T)$'s along the c axis [$H_{c2}^c(T)$] and in an $ab$-planar direction [$H_{c2}^{ab}(T)$] exhibit a linear and a sublinear increase, respectively, with decreasing temperature below the superconducting transition. $H_{c2}(T)$'s in both directions deviate from the conventional one-gap Werthamer-Helfand-Hohenberg theoretical prediction at low temperatures. A two-gap nature and the paramagnetic pair-breaking effect are shown to be responsible for the temperature-dependent behavior of $H_{c2}^c$ and $H_{c2}^{ab}$, respectively.Comment: 21 pages, 8 figure