[Western Blot analysis of type I, III, V, VI collagen after laser epithelial keratomileusis and photorefractive keratectomy in cornea of rabbits].

Purpose: Use immunohistochemical staining and Western Blot analysis to observe and compare the accurate dynamic changes of type I, III, V, VI collagen in the wound healing processes of the rabbit cornea which underwent LASEK or PRK to investigate the possible mechanism of corneal haze and myopic regression.

Methods: New Zealand White rabbits were divided into 8 groups: normal control group (n=6), 1 day, 7 days, 1, 3, 4, 5 and 6 month groups (n=14). Every rabbit underwent LASEK in one eye while the other one with PRK.

Potential involvement of the cyclooxygenase-2 pathway in hepatocellular carcinoma-associated angiogenesis.

Angiogenesis plays a crucial role in tumor development and growth. The present study was carried out to investigate the potential involvement of the cyclooxygenase-2 (Cox-2) pathway in the regulation of angiogenesis in hepatocellular carcinoma (HCC). We inhibited Cox-2 expression in HCC cell line HuH-7 by selective Cox-2 inhibitor (SC-58635) or Cox-2 siRNA.

N,N-dimethyl-beta-alanine as an inexpensive and efficient ligand for palladium-catalyzed Heck reaction.

N,N-Dimethyl-beta-alanine was found to be a more powerful phosphine-free ligand than the previously reported ligand, N,N-dimethylglycine, in the Pd-catalyzed Heck reaction for a variety of aryl bromides, aryl iodides, and activated aryl chlorides with a practical turnover number of 10(3). Both kinetic and theoretical studies suggested that N,N-dimethyl-beta-alanine led to faster oxidative addition of an aryl halide to Pd than N,N-dimethylglycine. [reaction: see text]

[Fluorescence characteristics of dissolved organic matter during algal bloom in Jiaozhou Bay].

Fluorescence excitation-emission matrix spectroscopy (EEMS) was employed to characterize the dissolved organic matter (DOM) in algal bloom seawater of Jiaozhou Bay in February, 2004. The relationships of DOM fluorescence characteristics with phytoplankton multiplication, dissolved organic carbon (DOC), salinity, dissolved oxygen and pH were discussed. In addition, the protein-like and humic-like fluorescence changes fore and aft cross-flow ultrafiltration (CFF) were primarily evaluated.

Asymmetric transfer hydrogenation of imines and iminiums catalyzed by a water-soluble catalyst in water.

The first asymmetric transfer hydrogenation of cyclic imines and iminiums in water was successfully performed in high yields and enantioselectivities with sodium formate as the hydrogen source and CTAB as an additive catalyzed by a water-soluble and recyclable ruthenium(II) complex of the ligand (R,R)-2.

Design of highly enantioselective organocatalysts based on molecular recognition.

[reaction: see text] Various organocatalysts have been designed based on molecular recognition to catalyze the asymmetric direct aldol reaction of ketones with aryl and alkyl alpha-keto acids, affording beta-hydroxyl carboxylic acids with a tertiary stereogenic center with excellent enantioselectivities of up to 98% ee. A linear effect was observed for the reaction, demonstrating a single molecule of the catalyst involved in the catalysis.

Copper(II)-mediated resolution of alpha-halo carboxylic acids with chiral O,O'-dibenzoyltartaric acid: spontaneous racemization and crystallization-induced dynamic resolution.

Herein we present a new example of coordination-mediated resolution of racemic acids by a chiral acid. The reaction of copper(II) acetate monohydrate, optically pure O,O'-dibenzoyltartaric acid (DBTA) and racemic alpha-bromo-2-chlorophenylacetic acid (HL1) in acetonitrile solution afforded a binuclear copper(II) complex with D-DBTA dianion, alpha-bromo-2-chlorophenylacetate and acetate as ligands. After decomposition of the complex with acid, the optically active acid ((R)-HL1) was obtained.

Asymmetric nitroallylation of arylboronic acids with nitroallyl acetates catalyzed by chiral rhodium complexes and its application in a concise total synthesis of optically pure (+)-gamma-lycorane.

[reaction: see text]A new rhodium-catalyzed highly enantioselective nitroallylation of 2-nitrocyclohex-2-enol esters with arylboronic acids is described. A rhodium complex of [RhOH(COD)]2 and optically pure BINAP is the optimal catalyst that provides good yields and high enantioselectivities ranging from 90 to 99% ee for various arylboronic acids at 50 degrees C. A concise total synthesis of optically pure (+)-gamma-lycorane in overall 38% yield was achieved on the basis of this new method.

Improvement of phenylethanoid glycosides biosynthesis in Cistanche deserticola cell suspension cultures by chitosan elicitor.

Effect of chitosan elicitor on growth and phenylethanoid glycosides (PeGs) accumulation in Cistanche deserticola cell suspension cultures was investigated. PeGs accumulation was dramatically improved by addition of selected chitosan at optimal elicitation conditions. Furthermore, a strategy of repeated addition of the chitosan elicitor for enhancing PeGs accumulation was developed.

Transfer hydrogenation of activated C=C bonds catalyzed by ruthenium amido complexes: reaction scope, limitation, and enantioselectivity.

[reaction: see text] It was found that the chemoselectivity could be completely switched from C=O to C=C bonds in the transfer hydrogenation of activated alpha,beta-unsaturated ketones catalyzed by diamine-ruthenium complex. Moreover, this addition via metal hydride had been applied to the reduction of various activated olefins. The electron-withdrawing ability of functional groups substituted on C=C bonds at the alpha- or beta-position had strong influence on the reactivity.

[Antigen retrieval immunohistochemistry under the influence of pH value and time].

Objective: To find the best antigen retrieval buffer and retrieval time for the immunohistochemical staining of P504S, P63, CD10, and Ki-67.

Methods: The following tissues were fixed in 10% formalin: the tissues of prostate carcinoma, benign prostate hyperplasia, proliferative breast disease and cunnus epithelial tissue infected by human papilloma virus. Immunohistochemical stainings for these tissues were processed by EnVision's methods.

Enantioselective direct aldol reactions catalyzed by L-prolinamide derivatives.

l-Prolinamides 2, prepared from l-proline and simple aliphatic and aromatic amines, have been found to be active catalysts for the direct aldol reaction of 4-nitrobenzaldehyde with neat acetone at room temperature. They give moderate enantioselectivities of up to 46% enantiomeric excess (ee). The enantioselectivity increases as the amide N-H becomes a better hydrogen bond donor.

Modification of (1R,2S)-1,2-diphenyl-2-aminoethanol for the highly enantioselective, asymmetric alkylation of N-diphenylphosphinoyl arylimines with dialkylzinc.

Experimental studies on the modification of (1R,2S)-1,2-diphenyl-2-aminoethanol, which is used to promote the alkylation of N-diphenylphosphinoyl benzalimine with diethylzinc, revealed that N-monosubstituted amino alcohols exhibited higher enantioselectivities than their N,N-disubstituted counterparts and imino alcohols. Application of the optimal chiral ligand 3c to activate the reaction of N-diphenylphosphinoyl arylimines with diethylzinc and dibutylzinc resulted in excellent enantiomeric selectivities of up to 98% ee. The origin of the experimentally observed enantioselectivities was revealed by density functional calculations (B3LYP/6-31G*) on the transition structures of several model reactions.

Facile preparation of optically pure 7,7'-disubstituted BINOLs and their application in asymmetric catalysis.

A family of optically pure 7,7'-disubsituted-2,2'-dihydroxy-1,1'-dinaphthyls have been conveniently prepared from easily accessible 7-alloxyl-2-naphthol by reaction sequences beginning with the asymmetric oxidative coupling and followed by key synthetic steps including deprotection, alkylation, and Suzuki coupling. Application of these binaphthols in catalytic phenylacetylene addition to aldehydes resulted in excellent enantioselectivities.

Facile resolution of racemic terbutaline and a study of molecular recognition through chiral supramolecules based on enantiodifferentiating self-assembly.

An effective resolving agent, (2S, 3S)-di-O-(p-toluoyl) tartaric acid(4), was screened using a 'family' approach to yield direct resolution of (R)-terbutaline (1) with high optical purity and yield. Molecular recognition was studied by X-ray crystallographic analyses of the single crystals of the pair of diastereomeric salts. The more-soluble salt formed a sheet supramolecular structure, and the less-soluble salt formed a columnar supramolecular structure by enantiodifferentiating self-assembly.

Facile optical resolution of tert-butanethiosulfinate by molecular complexation with (R)-BINOL and study of chiral discrimination of the diastereomeric complexes.

An important synthon, tert-butanethiosulfinate (2), has been effectively resolved by forming molecular complexes with (R)-2,2'-dihydroxy-1,1'-binaphthyl (BINOL, 3) in high enantioselectivity (>99 % ee). The present procedure represents the first example of the resolution of thiosulfinate. The mechanism of chiral discrimination is discussed in terms of molecular recognition based on IR and Xray analyses of the diastereomeric complexes during the resolution.

Asymmetric transfer hydrogenation of prochiral ketones in aqueous media with new water-soluble chiral vicinal diamine as ligand.

[reaction: see text] An easily accessible water-soluble chiral o-sulfonated 1,2-diphenylethlenediamine 2 and its mono-N-tosylated derivative 3 were synthesized for the first time. The ruthenium-complex-catalyzed reduction of prochiral ketones in aqueous media has been examined by using 3 as ligand and sodium formate as the source of hydrogen. The asymmetric transfer hydrogenation of omega-bromo acetophenones was achieved, in which only formate displacement occurred when formic acid/triethylamine azeotrope was used as the hydrogen donor.

Evaluation of chiral oxazolines for the highly enantioselective diethylzinc addition to N-(diphenylphosphinoyl) imines.

On the basis of the principle that the incorporation of the structurally rigid and conformationally restricted skeleton in beta-amino alcohols is beneficial to the enantioselective diethylzinc addition to imines, a series of chiral oxazolines, which had been designed and conveniently prepared from commercially available (1S,2S)-2-amino-1-phenylpropane-1,3-diol, were applied in the diethylzinc addition to diphenylphosphinoyl imines to give high yields of 68-84% and excellent ee values of 90-95%. The configuration of the product was controlled by the chirality of the carbon bonded to the hydroxyl group in the oxazoline. Oxazolines bearing a para- or meta-substituted phenyl group generally offered higher enantioselectivity than those containing an ortho-substituted phenyl.

Novel small organic molecules for a highly enantioselective direct aldol reaction.

Novel organic molecules containing an l-proline amide moiety and a terminal hydroxyl for catalyzing direct asymmetric aldol reactions of aldehydes in neat acetone are designed and prepared. Catalyst 3d, prepared from l-proline and (1S,2S)-diphenyl-2-aminoethanol, exhibits high enantioselectivities of up to 93% ee for aromatic aldehydes and up to >99% ee for aliphatic aldehydes. A theoretical study of transition structures demonstrates the important role of the terminal hydroxyl group in the catalyst in the stereodiscrimination.

Multiple dendritic catalysts for asymmetric transfer hydrogenation.

The first and second generation multiple dendritic ligands based on chiral diamine were synthesized in a convergent approach and were well-characterized by NMR and MS techniques. Their ruthenium complexes prepared in situ had good solubility in the reaction medium (azeotrope of formic acid and triethylamine) and demonstrated high catalytic activity and enantioselectivity comparable to monomeric catalysts in the asymmetric transfer hydrogenation of ketones and imines. Quantitative yields and for some cases a slightly higher enantioselectivity (up to 98.

The rational design of novel chiral oxovanadium(IV) complexes for highly enantioselective oxidative coupling of 2-naphthols.

Several novel chiral oxovanadium(IV) complexes have been designed and prepared for the asymmetric catalytic oxidative coupling of 2-naphthols with high enantioselectivities of 83-98% ee.

Highly enantioselective diethylzinc addition to imines employing readily available N-monosubstituted amino alcohols.

An easily accessible chiral ligand 3c, which promoted diethylzinc addition to imines with 96-98% ee, has been found by finely screening N,N-disubstituted and N-monosubstituted amino alcohols. N-monosubstituted amino alcohols, on average, gave slightly higher enantioselectivities than their N,N-disubstituted analogues. These results imply that the restricted and rigid structure of amino alcohol is not the absolute requirement for the highly enantioselective dialkylzinc addition to diphenylphosphinoylimines.

A highly enantioselective hetero-Diels-Alder reaction of aldehydes with Danishefsky's diene catalyzed by chiral titanium(IV) 5,5',6,6',7,7',8,8'-octahydro-1,1'-bi-2-naphthol complexes.

The catalytic effect of chiral Lewis acids on the hetero-Diels-Alder reaction between aldehydes and Danishefsky's diene (1) has been investigated. A variety of combinations of different ligands and Lewis acids have been examined as catalysts for the hetero-Diels-Alder reaction between benzaldehyde and 1, and it has been found that the readily accessible Ti(IV)-H(8)-BINOL (TiHBOL) complex is a very effective catalyst for the reaction, leading to products with very high enantioselectivity (up to 99% ee) and yield (92%). The hetero-Diels-Alder reaction of other aldehydes with 1 under the catalysis of TiHBOL is a general reaction which proceeds well with very high enantioselectivity and isolated yield for various aldehydes at 0 degrees C to room temperature.