Induced chiral helical effect on the main chain of aliphatic polyacetylenes

11‐Dodecyn‐1‐ol as an achiral, aliphatic, monosubstituted acetylene was copolymerized with cholesteryl 3‐butynyl carbonate as a chiral, aliphatic, monosubstituted acetylene with Rh(nbd)[B(C₆H₅)₄] (nbd = norbornadiene) in tetrahydrofuran. The main chain of the obtained copolymers seemed to be mainly composed of the cis‐type structure. The backbone π–π* transition of these copolymers showed significant circular dichroism (CD), indicating an excess of one‐handed helical conformation. These CD signals were varied with the contents of the cholesteryl units in the copolymers. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 913–917, 2001     

Pipette tip biosensors for bacterial double-stranded DNA using bioluminescence induced by zinc finger luciferase

The authors describe a pipette type of biosensor for detecting target genes and using a zinc finger protein fused to luciferase (ZF luciferase). The ZF protein binds to a specific DNA sequence, and the target double-stranded (ds) DNA can be detected by monitoring the enzymatic activity of ZF luciferase. A small avidin-immobilized reaction plate is placed on a plastic pipette tip (referred to as Biologi tip). The dsDNA detection procedures are carried out by using a programmable dispensing robot equipped with a photodetector. These procedures include (a) the aspiration of an analyte to capture the biotinylated target dsDNA (a product of a polymerase chain reaction) on the small reaction plate inside the pipette tip, (b) the introduction of ZF luciferase and luciferin into the pipette tip, and (c) migration of the pipette tip to the detection port to measure bioluminescence on the small reaction plate. The emission originating from luciferase activity is observed on the reaction plate containing immobilized biotin-tagged target dsDNA, whereas plates containing non-target or biotinylated single-stranded DNA only do not yield a signal. The intensity of emission increases proportionally to the concentration of dsDNA, and the detection limit of the target dsDNA is as low as 62 pM. An actual genomic DNA sample from Escherichia coli O157 was successfully detected by this automatic analyzer using the Biologi tip equipped with a reaction plate. This indicates that this system has a large potential for practical applications, including in particular point-of-care analyses in hygiene control, food safety testing, and clinical diagnosis.

Open image in new window

Graphical abstract A pipette-type biosensor was developed to detect target genes using a luciferase-fused zinc finger protein, where a small NeutrAvidin-immobilized reaction plate was placed on the tip, and the biotinylated target double-stranded DNA was detected by monitoring the bound luciferase activity.

     

Isolation of o-xylylene (o-quinodimethane) dirivatives. A strong through-bond interaction in 2,3-benzobicyclo[2.2.0]hexane system

Some o-xylylene (o-quinodimethane) derivatives were isolated as stable cyrstalline materials. A strong through-bond interaction in tetracyanoethylene addition product of tetraphenylbenzodicyclobutadiene ($\text{21}$ is suggested.     

DESIGN AND PERFORMANCE OF THE OKAZAKI LARGE SPECTROGRAPH FOR PHOTOBIOLOGICAL RESEARCH

A computer-operated spectrograph was recently built at Okazaki, Japan. Different specimens can be placed on a horseshoe-shaped focal curve (10 m long) covering a wavelength range of 250 to 1000 nm so they can be irradiated simultaneously. The linear dispersion is about 0.8 nm/cm. The photon fluence rate on the focal curve is 5 x 10¹⁵. photons x cm^-2 x s^-1 at 300nm and 1 x 10¹⁶ photons x cm^-2 x s^-1 at 600 and at 900 nm. The spectral half width is 5.5 nm or less on the focal curve. The stray light content is about 10^-5 of the main peak at the peak wavelength ± 100 nm. Specimens are set in microcomputer-controlled threshold boxes so that wavelengths, photon fluence rates, photon fluences and timing of irradiations are controlled automatically according to a pre-programmed schedule. An optical fiber system is also provided for remote irradiations.     

Optically detected electron—nuclear double resonance and electron—nuclear—nuclear triple resonance study of 17O hyperfine coupling in the lowest nπ* triplet state of benzil

Optically detected ENDOR and electron—nuclear—nuclear triple resonance of ¹⁷O were measured via phosphorescence from ³(nπ^*) benzil in benzophenone-d₁₀ crystals at high magnetic field. The n and π^* spin densities on the oxygen atom are 0.201 and 0.092, respectively, the angle between the two CO bonds being 150°.     

A singular value decomposition algorithm based on solving hyperplane constrained nonlinear systems

A new algorithm for singular value decomposition (SVD) is presented through relating SVD problem to nonlinear systems whose solutions are constrained on hyperplanes. The hyperplane constrained nonlinear systems are solved with the help of Newton’s iterative method. It is proved that our SVD algorithm has the quadratic convergence substantially and all singular pairs are computable. These facts are also confirmed by some numerical examples.     

Stochastic exponential synchronization of jumping chaotic neural networks with mixed delays

This paper deals with the exponential synchronization problem for a class of stochastic jumping chaotic neural networks with mixed delays and sector bounded nonlinearities. The mixed time delays under consideration comprise both discrete time-varying delays and distributed time delays. By applying the Finsler’s Lemma and constructing appropriate Lyapunov-Krasovskii functional based on delay partitioning, several improved delay-dependent feedback controllers with sector nonlinearities are developed to achieve the synchronization in mean square in terms of linear matrix inequalities. It is established theoretically that two special cases of the obtained criteria are less conservative than some existing results but including fewer slack variables. As the present conditions involve no free weighting matrices, the computational burden is largely reduced. One numerical example is provided to demonstrate the effectiveness of the theoretical results.     

Theory of raman scattering from molecules. Summation over vibrational states

Upper and lower bounds of the vibrational sums involved in the polanzability tensor are derived. The lower bound leads to a simplified formula applicable to resonance Raman scattering in both weak and strong coupling cases. A new expansion of the vibrational sum is introduced and useful expressions for excitation profiles are obtained.     

Sequential Upscaling Method

This paper presents a new method for scaling up multiphase flow properties which properly accounts for boundary conditions on the upscaled cell. The scale-up proposed does not require the simulation of a complete finely-gridded model, instead it calls for assumptions allowing the calculation of the boundary conditions related to each block being scaled up. To upscale a coarse block, we have to assume or determine the proper boundary conditions for that coarse block. To date, most scale-up methods have been based on the assumption of steady-state flow associated with uniform fractional flows over all the boundaries of the coarse block. However, such an assumption is not strictly valid when we consider heterogeneities. The concept of injection tubes is introduced: these are hypothetical streamtubes connecting the injection wellbore to all inlet faces of the fine grid cells constituting the block to be scaled up. Injection tubes allow the capturing of the fine-scale flow behavior of a finely-gridded model at the inlet face of the coarse block without having to simulate that fine grid. We describe how to scale up an entire finely-gridded model sequentially using injection tubes to determine the boundary conditions for two-phase flow. This new scale-up method is able to capture almost exactly the fine-scale two-phase flow behavior, such as saturation distributions, inside each isolated coarse-grid domain. Further, the resultant scaled-up relative permeabilities reproduce accurately the spatially-averaged performance of the finely-gridded model throughout the simulation period. The method has been shown to be applicable not only to viscous-dominated flow but also to flow affected by gravity for reasonable viscous-to-gravity ratios.     

Proton acceleration to 40 MeV using a high intensity, high contrast optical parametric chirped-pulse amplification/Ti:sapphire hybrid laser system

Using a high-contrast (10(10):1) and high-intensity (10(21) W/cm(2)) laser pulse with the duration of 40 fs from an optical parametric chirped-pulse amplification/Ti:sapphire laser, a 40 MeV proton bunch is obtained, which is a record for laser pulse with energy less than 10 J. The efficiency for generation of protons with kinetic energy above 15 MeV is 0.1%.