N21,N22‐carbonyl‐bridged biliverdin. red‐blue color change effected by conformation

An N₂₁,N₂₂‐carbonyl‐bridged mesobiliverdin, prepared in high yield by reaction of the unbridged parent (λ_max 639 nm, ? 15,700, chloroform) with 1,1′‐carbonyldiimidazole and 1,8‐diazabicyclo[5.4.0]undec‐7‐ene, gave magenta‐colored solutions in chloroform that absorb strongly in the visible spectrum (λ_max 534 nm, ? 27,700) and shifted to bright blue (λ_max 669 nm, ? 35,300) upon addition of trifluoroacetic acid.     

Stereospecific Bromine Replacement in the Synthesis of 4(e) and 4(a)-Deuterioadamantan-2-ones

Stereospecific introduction of deuterium on the adamantane skeleton has been accomplished with LiAID(OCH₃)₃-CuI.     

On Mixed Pressure-Velocity Regularity Criteria to the Navier-stokes Equations in Lorentz Spaces,Part Ⅱ:The Non-slip Boundary Value Problem

This paper is a continuation of the authors recent work [Beir?o da Veiga, H.and Yang, J., On mixed pressure-velocity regularity criteria to the Navier-Stokes equations in Lorentz spaces, Chin. Ann. Math., 42(1), 2021, 1–16], in which mixed pressure-velocity criteria in Lorentz spaces for Leray-Hopf weak solutions of the three-dimensional NavierStokes equations, in the whole space R~3 and in the periodic torus T~3, are established. The purpose of the present work is to extend the result of mentio...     

A new proposal for the discretization of the Griffin—Wheeler—Hartree—Fock equations

A polynomial expansion is proposed as a new way to discretize the Griffin-Wheeler-Hartree-Fock equations of the Generator Coordinate Hartree-Fock method. The implementation of the polynomial expansion in the Generator Coordinate Hartree-Fock method discretizes the Griffin-Wheeler-Hartree-Fock equations through a numerical mesh which is not equally spaced. This procedure makes the optimization of Gaussian exponents in the Generator Coordinate Hartree-Fock method more flexible and more efficient. The results obtained with the polynomial expansion for atomic Hartree-Fock energies show this technique is very powerful when employed in the design of compact and high accurate Gaussian basis sets used in ab initio non-relativistic (Hartree-Fock) and relativistic (Dirac-Fock) calculations.     

A Fuzzy Logic Approach to Buffer Management in ATM Networks

A fuzzy buffer controller is developed to minimize cell loss in ATM switches. The proposed fuzzy controller sequences cells in buffers based upon the corresponding priority class, end-to-end delay parameter and congestion status. Cells are then scheduled and/or discarded according to their sequenced positions.     

COMPONENT ALLEE EFFECTS AND STAGE‐SPECIFIC PREDATION: A BRIEF INSIGHT INTO CONSERVATION AND BIOLOGICAL CONTROL ISSUES

In this paper, we propose a two‐stage structured population model subject to component Allee effects in fecundity and maturation, and with two disturbances (predation only and harvest and predation) acting on both stages. It is shown that this combination leads to a demographic Allee effect—a characteristic that could be exploited in pest biological control, but on the other hand, it represents a bane in conservation biology. The analysis is performed for disturbances with functional responses type 2 and 3, and the models show that they yield qualitatively similar results. This characteristic is discussed from the species conservation and biological control point of view, together with possible extensions of this work.     

基于多分辨分析的沪深股市相关性分析

为了有效地揭示沪深股市不同交易周期股票交易的相关性,本文采用极大重叠离散小波变换,将上证指数和深圳成指高频收益率分解在不同的交易周期上,对各个周期的收益率采用semi-GPD模型作为其边缘分布分别进行拟合,在此基础上采用Copula函数方法建立同周期收益率的联合分布,度量了沪深两市同周期交易的相关性.实证表明,不同交易周期所表现出的相关性存在明显差异,并且随着交易期的增长,沪深两市非对称结构逐步明显。     

Synthesis and conformational analysis of a chiral fluorinated bilirubin analog lacking carboxyl groups

An optically active analog 1 of etiobilirubin-IVγ with a single fluorine on each of the C(8) and C(12) alkyl groups has been synthesized in order to examine its potential for hydrogen bonding with fluorine. Circular dichroism spectroscopy reveals an unusually strong influence of 2,2,2-trifluoroethanol solvent on diastereo-selection of the M-helical conformation of (8¹S,12¹S)-1.