Lipid analog with 2-nitrophenol trigger designed for liposome fusion at physiological pH

A novel lipid analog with two long alkyl (C₁₆) chains, an aspartate skeleton, a connecting alkyl (C₈) chain, and 2-nitrophenol trigger group is synthesized by an efficient synthetic route, which can induce liposome fusion at physiological pH.     

Preparation of carbon microparticle assemblies from phenolic resin using an inverse opal templating method

Three-dimensionally (3D) well-ordered carbon microparticle assemblies with different particle morphologies were fabricated by infiltration of phenolic resin solution into SiO₂ inverse opal structures and subsequent carbonization. The effect of the phenolic resin solution concentration and the carbonization temperature on the morphology of the fabricated carbon microparticles was investigated. At a carbonization temperature of 1000 °C, carbon microparticles with interlocked bridges were obtained when the concentration of phenolic resin solution is 40 wt% and hollow carbon microparticles with opened window channels were obtained at a concentration of 30–35 wt%. When the carbonization temperature was decreased to 500 °C, carbon microparticles with interlocked bridges also were observed, even when the phenolic resin concentration was 30 wt%. The structures and properties of the carbon microparticles and their assemblies were characterized using SEM, XRD, and N₂ adsorption.     

Synthesis and properties of ellipsoidal hematite/silicone core-shell particles

Monodispersed ellipsoidal hematite particles were synthesized and coated with silicone using a silane-coupling agent, phenyltriethoxysilane. The thickness of the silicone shell was controlled by the concentration of phenyltriethoxysilane and the presence of n-hexadecyltrimethylammonium chloride, which was thought to modify the surface properties of the hematite particles to be organophilic. The hematite/silicone core-shell particles were strongly hydrophobic and had a good dispersibility and stability in toluene. Hollow ellipsoidal silicone particles were obtained by the dissolution of hematite with hydrochloric acid from the core-shell particles.     

A reinforcement learning with switching controllers for a continuous action space

Reinforcement learning (RL) attracts much attention as a technique for realizing computational intelligence such as adaptive and autonomous decentralized systems. In general, however, it is not easy to put RL to practical use. This difficulty includes the problem of designing a suitable action space for an agent, i.e., satisfying two requirements in trade-off: (i) to keep the characteristics (or structure) of an original search space as much as possible in order to seek strategies that lie close to the optimal, and (ii) to reduce the search space as much as possible in order to expedite the learning process. In order to design a suitable action space adaptively, in this article, we propose a RL model with switching controllers based on Q-learning and an actor-critic to mimic the process of an infant’s motor development in which gross motor skills develop before fine motor skills. Then a method for switching controllers is constructed by introducing and referring to the “entropy.” Further, through computational experiments by using a path-planning problem with continuous action space, the validity and potential of the proposed method have been confirmed.     

In Situ Observation of Deformation in Semi-solid Fe-C Alloys at High Shear Rate

Synchrotron X-ray radiography at 125 frames per second was used to study deformation mechanisms in semi-solid Fe-C alloys at high solid fraction and shear strain rates of 10^?1/s. An image correlation approach was also used to quantify the shear strain fields and study shear-induced dilation and the origin of shear cracking. It was shown that, at high solid fraction (90 to 93 pct solid), rearrangement including rotation and translation of solid particles became restricted and shear strain localized into narrow liquid-filled channels/fissures. Shear cracking was shown to originate from inadequate liquid flow into the expanding spaces between solid particles caused by shear-induced dilation. At lower solid fraction (~85 pct solid), solid particles rearranged with a significantly higher component of rotation leading to more shear-induced dilation and a wider shear band.     

Sintering Kinetics at Isothermal Shrinkage: Effect of Specific Surface Area on the Initial Sintering Stage of Fine Zirconia Powder

The isothermal shrinkage behaviors of fine zirconia powders (containing 2.8–2.9 mol% Y₂O₃) with specific surface areas of about 6 and 16 m²/g were investigated to clarify the effect of specific surface area on the initial sintering stage. The shrinkage of powder compact was measured under constant temperatures in the range of 1000°–1100°C. The increase in specific surface area enhanced the densification rate with increasing temperature. The values of activation energy ( Q ) and frequency-factor term (β₀) of diffusion at initial sintering were estimated by applying the sintering-rate equation to the isothermal shrinkage data. The Q of diffusion changes little but the β₀ increases with the increase in specific surface area. It is therefore concluded that the increase in the specific surface area of fine zirconia powder enhances the shrinkage rate because of an increase in the β₀ at the initial stage of sintering.     

Damage Analysis of Hanshin Expressway Viaducts during 1995 Kobe Earthquake. III: Three-Span Continuous Girder Bridges

Almost all the single reinforced concrete (RC) piers from P35 to P350 received consistently severe damage, considering the large residual inclination of piers included in earthquake-induced severe damage. However, some of the piers in the section from P35 to P350 remained lightly damaged, and this phenomenon is observed especially in many piers under fixed bearings in continuous girder bridges. In this study, using experimentally based models for metal bearings and installing them to an existing FEM code, a nonlinear dynamic response analysis of a continuous girder bridge system is conducted. It is shown that the results depend on the ground motion, but the fuse effect of the breaking of the bearings could have been a reason for the phenomenon.     

A 144-Mb, eight-level NAND flash memory with optimized pulsewidthprogramming

We report a fast-programming, compact sense and latch (SL) circuit to realize an eight-level NAND flash memory. Fast programming is achieved by supplying optimized voltage and pulsewidth to the bit lines, according to the programming data. As a result, all data programming is completed almost simultaneously, and 0.67-MB/s program throughput, which is 1.7 times faster than conventional program throughput, is achieved. The compact layout of the SL circuit is made possible by four 3-bit latches sharing one unit of the read/verify control circuit. Using these techniques, we fabricated a 144-Mb, eight-level NAND flash memory using a 0.35-μm CMOS process, resulting in a 104.2-mm² die size and a 1.05-μm² effective cell size     

Hyper-Kloosterman Sums and their Applications to the Coding Theory

The dual code of the Melas code is called the Kloosterman code. The weights of its codewords can be expressed by the Kloosterman sums, and are uniformly distributed with respect to the Sato-Tate measure. In this paper, the hyper-Kloosterman code C _m (q), a generalization of the Kloosterman code is defined, and the uniform distribution property is deduced using the hyper-Kloosterman sums when m is even and p− 1|m. Finally we discuss doubly-evenness for the weights in the binary case. It shows that we can construct infinitely many doubly-even codes in a non-trivial way. Received: October 30, 2000; revised version: February 28, 2001     

Partition of Mn during the growth of proeutectoid ferrite allotriomorphs in an Fe-1.6 at. pct C-2.8 at. pct Mn alloy

A STEM analysis is made of the Mn distribution around grain boundary allotriomorphs of proeutectoid ferrite in an Fe-1.6 at. Pct C-2.8 at. Pct Mn alloy. Whereas the Mn enriched region is readily observed to extend along the austenite grain boundary, no substantial build-up or depletion of Mn near the ferrite : austenite interface is detected, consistent with the electron probe microanalysis previously reported. In the temperature range where the partition-local equilibrium (P-LE) mode has been proposed to prevail, measured parabolic growth rate constantsfall 1 to 2 orders of magnitude above that predicted from this model, but also below that calculated from the paraequilibrium (PE) model by roughly the same amount. A modification of the theory of grain boundary diffusion-aided growth of precipitates,i.e., the collector/rejector plate mechanism, on the other hand, accounts fairly well for the observed growth kinetics of ferrite allotriomorphs. However, only a slightly better accounting than the P-LE model is provided by this mechanism for the temperature dependence of Mn partition. Data on Ni partition, obtained in an Fe-0.5 at. Pct C-3.1 at. Pct Ni alloy, are also analyzed with the rejector plate model.