Biomedical subjects

Yu-Liang Liu

Publications and source records attributed to Yu-Liang Liu.

5 recordsLinked to original sources

PubMed2006

Catalytic and highly enantioselective Friedel-Crafts alkylation of aromatic ethers with trifluoropyruvate under solvent-free conditions.

[Structure: see text] Highly enantioselective Friedel-Crafts alkylation of simple and aromatic ethers (4a-l) with 3,3,3-trifluoropyruvate (3) was accomplished by using chiral (4R,5S)-DiPh-BOX(1b)-Cu(OTf)2 complex (1 mol %) as a catalyst under solvent-free conditions. Excellent yields and enantioselectivities (90-93% ee, after recrystallization up to 99% ee) of the Friedel-Crafts alkylation products were obtained.

Journal Article↗

PubMed2006

[Study on dynamic spectrum and its frequency domain extracting method].

For non-invasive blood components detection using near-infrared spectrum, eliminating the influence of the individual difference is very important. In the non-invasive component measurement, the individual discrepancy refers to the difference of personal feature in measured tissues except the pulsatile component of artery blood, including hairs, horny layer, subcutaneous tissue, muscle, skeleton etc. It is declared that the individual discrepancy is different from the personal feature; it is an important factor blocking the practice of the technology. In the present article, a new method of detecting blood components is presented, which is based on the principle of photoplethysmography and Fourier transform. With this method, the influence of individual difference caused by skin and other tissues can be mostly eliminated, and the absorbance of artery blood could be obtained. The concept of the frequency domain extracting method was presented. The experiment was done and the dynamic spectrum which only evaluates the pulsatile part of the entire optical signal was obtained. The advantage of dynamic spectrum with frequency domain extracting method is analyzed. The result shows that the method can be realized and has many advantages.

English Abstract↗

PubMed2005

Phylogenetic analysis of eight genes of H9N2 subtype influenza virus: a mainland China strain possessing early isolates' genes that have been circulating.

H9N2 subtype influenza virus has become worldwide and prevalent in China. Previous studies illustrated that at least three sublineages had been established in terrestrial poultry of Eurasian avian. In this presentation, eight full-length genes of an H9N2 strain, A/Chicken/Shanghai/F/98 (Ck/SH/F/98) were obtained. Sequence analysis and phylogenetic studies were conducted by comparing eight genes with those of all the available H9N2 strains from the GenBank. The results showed that four genes (HA, NA, M and NS genes) of Ck/SH/F/98 were incorporated into the sublineage represented by the early mainland China strain, Ck/BJ/1/94. However, the other four of RNP genes of Ck/SH/F/98 did not show close relationship with those of the three known sublineages' viruses. Therefore, Ck/SH/F/98 was a natural reassortant between different sublineages. In addition, comparison showed that Ck/SH/F/98 could be a putative precursor of a later isolate from southern China, Dk/ST/1605/01, with at least six genes of both closely related, indicating genes of Ck/SH/F/98 and early isolates had ever been circulating. Further comparison in terms of molecular markers of species specificity of HA1 revealed that DK/ST/1605/01 also resembled Ck/SH/F/98 more than a common earlier duck strain. The results supported the idea of two-way transmission between terrestrial and aquatic birds that emphasized the importance to raise concerns on the natural evolution of all the eight genes of H9N2 avian influenza viruses.

Amino Acid Sequence↗

PubMed2004

[Construction of recombinant fowlpox virus expressing chicken IL-2 and assay of biologic activity of the product in vitro].

In order to determine the adjuvant effects of the chicken IL-2 (ChIL-2) on new generation vaccines, ChIL-2 gene was amplified from ConA-stimulated chicken spleen cells by RT-PCR and was directionally inserted into fowlpox virus (FPV) transferring vector p1175 under the control of FPV early/late promoter (PE/L), resulting in recombinant transferring vector p1175IL2. Then the p1175IL2 plasmid was transfected into chicken embryo fibroblasts (CEF) pre-infected with wild type FPV to generate recombinant fowlpox virus expressing ChIL-2 (rFPV-IL2). By selection of blue plaques on the CEF, overlaid with agar containing X-gal, rFPV-IL2 was obtained and purified. The supernatant from CEF monolayer infected with rFPV-IL2 (M.O.I2.0) after 72 hours was detected for the production of ChIL-2 by XTT/PMS colorimetric assay. About 3.6 x 10(5) u/mL of specific ChIL-2 activity was determined. The results show that rFPV-IL2 can express ChIL-2 effectively. rFPV-IL2 provides us with an effective tool for studying avian immunology as well as a potential vaccine-enhancing agent.

Animals↗

PubMed2003

Finite element analysis of the cervico-trochanteric stemless femoral prosthesis.

OBJECTIVE: To investigate the biomechanical performance of a newly designed cervico-trochanteric stemless prosthesis by comparing the stress distribution with that of the traditional stem-type porous-coated anatomic prosthesis. DESIGN: Three-dimensional finite element models were created for the intact femur, cervico-trochanteric implanted femur and porous-coated anatomic implanted femur. The stress distributions on the femur and the implant were compared. The effects of using two or three screws fixation for the cervico-trochanteric implanted femur were also investigated. BACKGROUND: Local bone loss after implantation of traditional stem-type prostheses remains an unsolved problem during the long-term application of total hip replacement. The stress shielding effect and osteolysis were thought to be the two main factors that result in local bone loss after prosthesis implantation. In order to eliminate the mechanical and the biological causes of bone loss after total hip arthroplasty, a newly designed stemless femoral prosthesis was investigated. METHODS: Three-dimensional finite element models were created for the intact, cervico-trochanteric (with two or three fixation screws), and porous-coated anatomic implanted femora with the geometry of a standardized composite femur. Analysis was performed for a loading condition simulating the single-legged stance. The von Mises stress distributions of each model were analyzed and compared. RESULTS: The results can be summarized as follows: (1) Von Mises stress in the proximal, medial femur for the cervico-trochanteric implanted model was higher than that of the intact model and the porous-coated anatomic implanted model; (2) stress-shielding effect of the cervico-trochanteric models (with two or three fixation screws) were eliminated as compared with the porous-coated anatomic model; (3) no obvious difference in von Mises stress distribution for the cervico-trochanteric implanted model with two or three fixation screws. CONCLUSIONS: The cervico-trochanteric femoral prosthesis may reduce the stress-shielding effect of the proximal femur and achieve a more physiological stress distribution on the proximal femur than that of the porous-coated anatomic prosthesis. RELEVANCE: The new concept of cervico-trochanteric stemless prosthesis has proven to possess several advantages based on the current results, and may be an alternative for traditional stem-type prostheses in future clinical applications.

Biomechanical Phenomena↗