Comprehensive review in moisture retention mechanism of polysaccharides from algae,plants, bacteria and fungus

Polysaccharides have attracted much attention due to their significant bio-activities. This review aims to summarize the main polysaccharides sources of related polysaccharides from algae, plants, fungus, and bacteria, and give insights into the structure–activity relationship between the moisture retention and structural characteristics of polysaccharides. The molecular weight, functional groups, polysaccharide modifications and apparent structure of polysaccharides are closely related to the moisturizing properties of polysaccharides in terms of moisturizing conformation. Based on recent moisturizing pieces of evidence, we propose a new framework focusing on the moisturizing intrinsic and extrinsic mechanisms. Polysaccharides molecular weight has different effects on moisturizing property. The extrinsic moisturization is mainly via the formation of hydrogen bonds between polysaccharides, the intrinsic moisturizing is mainly by regulating the production of some tight junction proteins. Accordingly, this review could further open the door for the production and application of polysaccharides as novel moisturizing agents in the cosmetic field.     

Helical Carbon Nanotubes: Intrinsic Peroxidase Catalytic Activity and Its Application for Biocatalysis and Biosensing

A combined hydrothermal/hydrogen reduction method has been developed for the mass production of helical carbon nanotubes (HCNTs) by the pyrolysis of acetylene at 475 °C in the presence of Fe₃O₄ nanoparticles. The synthesized HCNTs have been characterized by high‐resolution transmission electron microscopy, scanning electron microscopy, X‐ray diffraction analysis, vibrating sample magnetometry, and contact‐angle measurements. The as‐prepared helical‐structured carbon nanotubes have a large specific surface area and high peroxidase‐like activity. Catalysis was found to follow Michaelis–Menten kinetics and the HCNTs showed strong affinity for both H₂O₂ and 3,3′,5,5′,‐tetramethylbenzidine (TMB). Based on the high activity, the HCNTs were firstly used to develop a biocatalyst and amperometric sensor. At pH 7.0, the constructed amperometric sensor showed a linear range for the detection of H₂O₂ from 0.5 to 115 μM with a correlation coefficient of 0.999 without the need for an electron‐transfer mediator. Because of their low cost and high stability, these novel metallic HCNTs represent a promising candidate as mimetic enzymes and may find a wide range of new applications, such as in biocatalysis, immunoassay, and environmental monitoring.     

A high-resolution finite-difference method for simulating two-fluid,viscoelastic gel dynamics

An important class of gels are those composed of a polymer network and fluid solvent. The mechanical and rheological properties of these two-fluid gels can change dramatically in response to temperature, stress, and chemical stimulus. Because of their adaptivity, these gels are important in many biological systems, e.g. gels make up the cytoplasm of cells and the mucus in the respiratory and digestive systems, and they are involved in the formation of blood clots. In this study we consider a mathematical model for gels that treats the network phase as a viscoelastic fluid with spatially and temporally varying material parameters and treats the solvent phase as a viscous Newtonian fluid. The dynamics are governed by a coupled system of time-dependent partial differential equations which consist of transport equations for the two phases, constitutive equations for the viscoelastic stresses, two coupled momentum equations for the velocity fields of the two fluids, and a volume-averaged incompressibility constraint. We present a numerical method based on a staggered grid, second order finite-difference discretization of the momentum equations and a high-resolution unsplit Godunov method for the transport equations. The momentum and incompressibility equations are solved in a coupled manner with the Generalized Minimum Residual (GMRES) method using a multigrid preconditioner based on box-relaxation. We present results on the accuracy and robustness of the method together with an illustration of the interesting behavior of this gel model for the four-roll mill problem.     

The integral convexity of sets and functionals in Banach spaces

By way of the Bochner integral of vector-valued functions, the integral convexity of sets and functionals and the concept of integral extreme points of sets are introduced in Banach spaces. The relations between integral convexity and convexity are mainly discussed, two integral extreme points theorems and their applications are obtained at last.     

抗菌药物柳氮磺胺镉配聚物的合成和晶体结构

0 Introduction Crystal engineering of pharmaceutical solids rep- resents a fertile and emerging research filed[1]. The im- petus for discovery of diverse crystal forms of drugs stems from the critical need to balance stability, bioavailability and other performance characteristics as well as provides valuable intellectual property pro- tection. Sulfasalazine (synonyms salazopyridine and salazosulfapyridine, abbreviated as H-SSZ) is a conju- gate of 5-aminosalicylic acid and sulfapyridine pos…     

异薄荷醇黄原酸镍的配合物(英)

The coordination geometry around Ni atom in the homochiral bis(2-isopropyl-5-methylcyclohexyl xanthalato) nickel(Ⅱ) (1) displays an approximately square plane defined by four S atoms from two xanthalato ligands. CCDC: 252343.     

Nonsolvable Groups with Three Nonlinear Irreducible Character Codegrees∗

For an irreducible character χ of a finite group G, the codegree of χ is defined as |G : ker(χ)|/χ(1). In this paper, the authors determine finite nonsolvable groups with exactly three nonlinear irreducible character codegrees, which are L2(2f ) for f ≥ 2, PGL2(q) for odd q ≥ 5 or M10.     

Lie Bialgebras of a Family of Lie Algebras of Block Type

Lie bialgebra structures on a family of Lie algebras of Block type are shown to be triangular coboundary.     

Group-invariant solutions of a integrable coupled system

In this paper, a new idea is put forward to modify the Clarkson–Kruskal's (CK's) direct method. By using the classical Lie group approach and the modified the CK's direct method, symmetry reductions and exact solutions are discussed for a integrable coupled KdV system. The group explanation for all the results obtained by the modified direct method is also given.