Widening Synthesis Bottlenecks: Realization of Ultrafast and Continuous‐Flow Synthesis of High‐Silica Zeolite SSZ‐13 for NOx Removal

Characteristics of zeolite formation, such as being kinetically slow and thermodynamically metastable, are the main bottlenecks that obstruct a fast zeolite synthesis. We present an ultrafast route, the first of its kind, to synthesize high‐silica zeolite SSZ‐13 in 10 min, instead of the several days usually required. Fast heating in a tubular reactor helps avoid thermal lag, and the synergistic effect of addition of a SSZ‐13 seed, choice of the proper aluminum source, and employment of high temperature prompted the crystallization. Thanks to the ultra‐short period of synthesis, we established a continuous‐flow preparation of SSZ‐13. The fast‐synthesized SSZ‐13, after copper‐ion exchange, exhibits outstanding performance in the ammonia selective catalytic reduction (NH₃‐SCR) of nitrogen oxides (NO_x), showing it to be a superior catalyst for NO_x removal. Our results indicate that the formation of high‐silica zeolites can be extremely fast if bottlenecks are effectively widened.     

Asymptotic distribution of the LR statistic for equality of the smallest eigenvalues in high-dimensional principal component analysis

This paper deals with the distribution of the LR statistic for testing the hypothesis that the smallest eigenvalues of a covariance matrix are equal. We derive an asymptotic null distribution of the LR statistic when the dimension p and the sample size N approach infinity, while the ratio p/N converging on a finite nonzero limit c(0,1). Numerical simulations revealed that our approximation is more accurate than the classical chi-square-type approximation as p increases in value.     

Ultraslow propagation of squeezed vacuum pulses with electromagnetically induced transparency

We have succeeded in observing ultraslow propagation of squeezed vacuum pulses with electromagnetically induced transparency. Squeezed vacuum pulses (probe lights) were incident on a laser-cooled 87Rb gas together with an intense coherent light (control light). A homodyne method sensitive to the vacuum state was employed for detecting the probe pulse passing through the gas. A delay of 3.1 micros was observed for the probe pulse having a temporal width of 10 micros.     

Dispersion of refractoriness and induction of reentry due to chaos synchronization in a model of cardiac tissue

Ventricular fibrillation is a lethal condition caused by multiple chaotically wandering electrical wavelets in the heart, reentering their own and each other's territories. The development of effective therapies requires a detailed understanding of how these reentrant waves are initiated. In this Letter, we demonstrate a novel mechanism for inducing reentry, in which chaos synchronization causes large-scale heterogeneities of refractoriness transverse to the direction of propagation. These regions of increased refractoriness create localized conduction block, which induces spiral wave reentry.     

New generation of the reference interaction site model self-consistent field method: introduction of spatial electron density distribution to the solvation theory

The authors propose the new generation of the reference interaction site model self-consistent field (RISM-SCF) method for the solvation effect on the electronic structure of a solute molecule, in which the procedure proposed by Gill et al. [J. Chem. Phys. 96, 7178 (1992)] is adopted. Main improvements are the introduction of spatial electron density distribution and the removal of the grid dependency that is inherent in the original RISM-SCF. The procedure also provides very stable determination of the effective charges even if a buried atom exists in the target molecule and eventually extends the applicability of the RISM-SCF. To demonstrate the superiority of our method, sample calculations for H2O, C2H5OH, and HLi in aqueous solution are presented.     

Arginine improves protein elution in hydrophobic interaction chromatography. The cases of human interleukin-6 and activin-A

The effects of arginine on protein binding and elution in hydrophobic interaction chromatography (HIC) were examined using recombinant human interleukin-6 (IL-6) and activin-A. Binding of IL-6 in the presence of ammonium sulfate (AS) was tested using low- and high-substituted phenyl-sepharose. While inclusion of arginine during loading of IL-6 resulted in incomplete binding to the low-substituted phenyl-sepharose, binding was complete to the high-substituted phenyl-sepharose. Arginine facilitated elution of IL-6 from both columns. These results demonstrate that arginine weakens hydrophobic interactions between IL-6 and the phenyl-sepharose. More drastic results were obtained using activin-A, which showed undetectable recovery from phenyl-sepharose. Although no apparent elution of activin-A was observed from butyl-sepharose in aqueous buffer alone, the addition of arginine to the buffer resulted in partial elution recovery and, together with ethanol, resulted in greatly improved recovery of the protein. Two arginine derivatives, acetylarginine and agmatine, were also effective. These results show that arginine improves protein elution in HIC.     

Synthesis and polymerization of novel fluorinated acrylates and methacrylates bearing alkoxyl groups derived from radical addition reaction of perfluoroisopropenyl ester

Radical addition of 2-benzoxypentafluoropropene [CF₂C(CF₃)OCOC₆H₅] (BPFP) with alcohols such as ethanol and 2-propanol was investigated to afford fluorinated alcohols. Radical addition of BPFP with cyclic ethers such as tetrahydrofuran, 1,3-dioxolane and tetrahydropyran was also achieved to afford addition products followed by hydrolysis to yield fluorinated alcohols possessing cyclic structures. Novel fluoroalkyl acrylates and methacrylates were synthesized from the fluorinated alcohols with (meth)acryloyl chlorides. Radical polymerization of the fluoroalkyl (meth)acrylates yielded polymers of 1.2 × 10⁵ as the highest molecular weight.     

Preparation of 4,5‐dihydro‐1,3‐selenazoles by reaction of aromatic primary selenoamides with acetylenedicarboxylate

Reactions of primary selenoamides with dimethyl acetylenedicarboxylate afforded 2‐aryl‐5‐methoxy‐carbonylmethylene‐4,5‐dihydro‐1,3‐selenazol‐4‐ones in moderate to high yields. Reactions of the primary selenoamides with acetylenedicarboxylic acid gave 2‐aryl‐5‐carboxymethylene‐4‐ethoxy‐4,5‐dihydro‐1,3‐selenazol‐4‐ols in moderate yields.     

A facile preparation of selenohydantoins using isoselenocyanate

Reactions of isoselenocyanate with methyl aminoacetate hydrochlorides in the presence of triethylamine afforded selenohydantoins, 2‐selenoxoimidazolidin‐4‐ones, in high yields.