A Novel Preparation of Artificial Bile Ducts for Clinical Application of Biliary Diseases

The aim of this paper was to prepare an artificial bile duct using polytetrafluoroethylene( PTFE) for the development of a new treatment for biliary diseases. The basic properties of the PTFE material,such as crystallization properties,were characterized; the surface structures of the sample tubes were observed by scanning electron microscope( SEM) and water permeability test of different tubes was evaluated by osmosis device. Six Shanghai white pigs were selected to do the implantation surgery of the artificial bile ducts. After 90 days,the artificial bile ducts were removed from the pigs and characterized by electron microscope in order to study the tissue compatibility. The results of animal test indicated that the artificial bile duct had good tissue compatibility. This new artificial bile duct shows great potential for the treatment of biliary diseases.

掺杂的化学计量比LiNbO_3单晶物理化学性能的改进

Lithium niobate LiNbO 3 is one of the most widely used non linear crystals.The melt grown crystals show typical non stoichiometric character.In the congruent crystal there are 5% of anti site Nb 5+ which are compensated by Li + vacancies.This kind of defect structure limits application of the crystal in several cases.In the ordered stoichiometric structure there are merely about 0.01% of anti site Nb 5+ ions. Non doped stoichiometric crystals exhibit significant changes of physical properties as compared with congruent ones,i.e. the blue shift of the absorption edge the narrowing of the spectral lines in EPR and NMR,Raman OH vibration etc.

Synthesis, Crystal Structure and Electrochemical Properties of 2-Chlorobenzaldehyde Thiosemicarbazone

The title compound crystallized in space group P21/c with Z=4, in a unit cell ofdimensions. a=12.964(4), b=5. 131(5), c=14.970(1)A, V=9331 (1) A3, Dc=1 .429gcm",P=0.541mm-1, R=0.045, Rw=0.059. The equilibrium constant of the ligand with CdBr2 wasobtained by polarograPhic method. Crystal structufe determination revealed that the molecule is intransconformation and non-hydrogen atoms of the molecule are in one plane except N(3) atom.

Applications of the crystallization process in the pharmaceutical industry

The applications of the crystallization technique in the pharmaceutical industry as a purification and separation process for the isolation and synthesis of pure active pharmaceutical ingredients(API),co-crystals,controlled release pulmonary drug delivery,and separation of chiral isomers are briefly discussed using a few case studies.The effect of process variables and solvent on the polymorphism and morphology of stavudine is discussed.The implementation of external control in the form of feedback and real-time optimal control using cooling and antisolvent crystallization of paracetamol in water-isopropyl alcohol is introduced.Two methods to prepare micronsized drug particles,namely,micro-crystallization and polymer-coated API-loaded magnetic nanoparticles for pulmonary drug delivery,are discussed.The significance of co-crystals in drug administration is highlighted using the theophylline-nicotinamide co-crystal system.Resolution of chloromandelic acid derivatives,a racemic compound,is achieved using direct crystallization and diastereomeric salts crystallization.The crystal structures of diastereomeric salts of chloromandelic acid and phenylethylamine are determined.The structure comparison between the less soluble and more soluble salts shows that weak interactions such as CH/πinteractions and van der Waals forces contribute to chiral recognition when the hydrogen bonding patterns are similar.

Effect of Soda Ash on Properties of Mold Flux and Mineralogical Structures of Flux Film

During continuous casting,properties of mold flux and mineralogical structures of flux film play important roles in controlling steel quality.The effect of soda ash on the physical properties and crystallization characteristics of mold flux was investigated using process mineralogy,including polarizing microscopy,X-ray diffraction,and electron microprobe,etc.Mold flux was mainly prepared using cement clinker and industrial mineral materials under laboratory conditions,and the mineralogical structures of the flux film were systematically identified and quantitatively analyzed.The results showed that,by increasing the soda ash content from 10mass% to 18mass%,the crystallization temperature,critical cooling rate and crystallization ratio of the flux film decreased,but the crystallization ratio still reached 75% after adding soda ash,and the mineral compositions and microstructures of the flux film changed slightly.When the soda ash content exceeded 14mass%,the critical cooling rate and the crystallization ratio decreased slightly,whereas the mineral content of the flux film changed evidently,with a large amount of cuspidine precipitation and a significant decrease in the wollastonite content until it reached zero,which resulted in deterioration of the lubrication of the flux film.

Study on Dispersion Properties of Photonic Crystal Fiber by Effective-Index Model

The group-velocity-dispersion properties of photonic crystal fiber (PCF) were investigated by effective-index model. The relationship between waveguide dispersion and structure parameters: the pitch A and the relative hole size/was studied.

The Gain Properties of 1-D Active Photonic Crystal

The terminology 'ID frequency'(w ID) is proposed after analyzing the 1D active photonic crystal based on the transfer matrix method. The relationship between wID and the structure parameters of the photonic crystal is investigated.