6 Y-SNP typing of China and Korean samples using primer extension and DHPLC.
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China↗
Biomedical subjects
Xiaojun Yu
Publications and source records attributed to Xiaojun Yu.
Enhanced second-harmonic generation in AlGaAs/AlxOy tightly confining waveguides and resonant cavities.
We demonstrate second-harmonic generation (SHG) from sub-micrometer-sized AlGaAs/AlxOy artificially birefringent waveguides. The normalized conversion efficiency is the highest ever reported. We further enhanced the SHG using a waveguide-embedded cavity formed by dichroic mirrors. Resonant enhancements as high as approximately 10x were observed. Such devices could be potentially used as highly efficient, ultracompact frequency converters in integrated photonic circuits.
Journal Article↗
Dichroic mirror embedded in a submicrometer waveguide for enhanced resonant nonlinear optical devices.
We report the design, fabrication and characterization of novel dichroic mirrors embedded in a tightly confining AlGaAs/Al(x)O(y) waveguide. Reflection at the first-harmonic wavelength as high as 93% is achieved, while high transmission is maintained at the second-harmonic wavelength. The measured cavity spectrum is in excellent agreement with finite-difference time-domain simulations. Such a mirror is essential for achieving resonant enhancement of second-harmonic generation.
Journal Article↗
Design of compliance chamber and after-load in apparatus for cultured endothelial cells subjected to stresses.
In order to create a hemodynamic environment that can simulate the physiological condition of arteries, an in vitro experiment apparatus was designed whose key modules were compliance chamber and after-load. These two modules were developed based on the theories of hemodynamics. Both the normal and shear stress to which endothelial cells are exposed can be controlled with these modules, thus facilitating the research of endothelial cells subjected to stresses.
Blood Pressure↗
The ABJS Nicolas Andry Award: Tissue engineering of bone and ligament: a 15-year perspective.
Musculoskeletal repair is a major challenge for orthopaedic surgeons. The burden of repair is compounded by supply constraints and morbidity associated with autograft and allograft tissue. We report 15 years of research regarding tissue engineering and biological substitutes for bone and ligaments. Our approach has focused on biomaterial selection, scaffold development, cell selection, cell/material interaction, and growth factor delivery. We have extensively tested poly(ester), poly(anhydride), poly(phosphazene) derivatives, and composite materials using biocompatibility, degradation, and mechanical analyses for bone and ligament tissue engineering. We have developed novel three-dimensional matrices with a pore structure and mechanical properties similar to native tissue. We also have reported on the attachment, growth, proliferation, and differentiation of cells cultured on several scaffolds. Through extensive molecular analysis, in vitro culture condition analysis, and in vivo evaluation, our findings provide new methods of bone tissue regeneration using three-dimensional tissue engineered scaffolds, bioactive bone cement composite materials, and three-dimensional tissue engineered scaffolds for ligament regeneration.
Animals↗
An experimental study on the biomechanical properties of the cancellous bones of distal femur.
OBJECTIVE: To study the comprehensive biomechanical properties of the cancellous bone of distal femur through a series of mechanical tests, and provide relevant subjects with the basic technical data. BACKGROUND: The study on bone mechanics is a commonly used approach to evaluate the biomechanical competency of bone. The biomechanical properties of bone have come to be the precondition of the further research of these relevant clinical subjects. METHOD: In this paper, comprehensive items of mechanical properties of the cancellous bones of distal femur were conducted, and many valuable test results were obtained through a series of mechanical tests, which comprised tensile test, compression test, torsion test, shear test, bending test and impact test. The specimens were extracted from the normal corpses of Chinese donors died from acute head injury. As another key problem in this kind of experiment, the sampling and fixing method of cancellous bones specimens was developed and optimized in this research. RESULT: A series of the experimental data of mechanical properties of cancellous bones were obtained in the tests, these experimental data include tensile strength, compression strength, yield tensile strength, modulus of elasticity, torsion strength, shear strength, torsion modulus, bending strength, yield shear limit and impact toughness, which can reflect the complex mechanical competency of bone, being of great value and practice in clinic and further research on cancellous bones. The mechanical properties of the cancellous bones of distal femur were analyzed and discussed. CONCLUSION: The biomechanical properties of the cancellous bones have a close relationship with individual difference. Comprehensive items of the mechanical properties of the bone can evaluate the mechanical performance of the bone better, and can provide more valuable data to relevant research.
Adult↗
[Dynamics of soil active organic matter in Chinese fir plantations].
Soil active organic matter is the main source of soil nutrients, and plays an important role in the formation and stabilization of soil aggregate. Chinese fir (Cunninghamia lanceolata) is the most important fast-growing timber tree species in southern China, but its continuous plantation has caused soil deterioration. The study on the active fractions of soil organic matter under the first and second generation plantations of Chinese fir and the native broad-leaved forest at Huitong Experimental Station of Forest Ecology, Chinese Academy of Sciences, in Hunan Province showed that their contents were higher under native broad-leaved forest than under Chinese fir plantations, and higher under the first than under the second generation plantation. The content of soil active organic carbon (SAOC), microbial biomass carbon (MBC), water-soluble organic carbon (WSOC) and water-soluble carbohydrate (WSC) was 18.79 g x kg(-1), 421.7 mg x kg(-1), 252.2 mg x kg(-1) and 136.3 mg x kg(-1) under the first generation plantation of Chinese fir, and 22.31 g x kg(-1), 800.5 mg x kg(-1), 361.1 mg x kg(-1) and 220.1 mg x kg(-1) under the native broad-leaved forest, respectively. The corresponding values under the second generation plantation of Chinese fir were 73.6%, 87.9%, 66.3% and 53.2% of those under the first generation plantation of Chinese fir. The results also indicated that there existed some extent correlations among the active fractions of soil organic matter, and higher correlations between soil microbial biomass carbon and other active fractions of soil organic matter.
Carbon↗
[Perforin and granzyme--the perfect material of biologic missile].
Perforin and granzyme are important effector molecules in cytolytic cells. They can induce apoptosis of tumor cells and infection cells. The research of biologic missile is noticed with the progress in therapy targeting to the disease. It is supposed that perforin and granzyme play an important role in biological missiles because of their biologic function and structure. A review on several aspects of these effector molecules is presented.
Animals↗
Bioreactor-based bone tissue engineering: the influence of dynamic flow on osteoblast phenotypic expression and matrix mineralization.
An important issue in tissue engineering concerns the possibility of limited tissue ingrowth in tissue-engineered constructs because of insufficient nutrient transport. We report a dynamic flow culture system using high-aspect-ratio vessel rotating bioreactors and 3D scaffolds for culturing rat calvarial osteoblast cells. 3D scaffolds were designed by mixing lighter-than-water (density, <1g/ml) and heavier-than-water (density, >1g/ml) microspheres of 85:15 poly(lactide-co-glycolide). We quantified the rate of 3D flow through the scaffolds by using a particle-tracking system, and the results suggest that motion trajectories and, therefore, the flow velocity around and through scaffolds in rotating bioreactors can be manipulated by varying the ratio of heavier-than-water to lighter-than-water microspheres. When rat primary calvarial cells were cultured on the scaffolds in bioreactors for 7 days, the 3D dynamic flow environment affected bone cell distribution and enhanced cell phenotypic expression and mineralized matrix synthesis within tissue-engineered constructs compared with static conditions. These studies provide a foundation for exploring the effects of dynamic flow on osteoblast function and provide important insight into the design and optimization of 3D scaffolds suitable in bioreactors for in vitro tissue engineering of bone.
Alkaline Phosphatase↗
[Researches in forensic biomechanics].
Forensic biomechanics is the science of proof, which applies the biomechanical theory and technology to resolve problems related to mechanics in the process of expert witness. It belongs to the realm of a new subject combining biomechanics and forensics. Forensic biomechanics is a new branch of modern biomechanics and at the same time a new important branch of forensics, and it is one of the most potential research areas in forensics of injury. In this paper, the task of forensic biomechanics expert witness, the procedure of expert witness, and the forensic biomechanics research methods and cases are reviewed.
Biomechanical Phenomena↗
[Development on study of zinc deficiency and immunity].
In this paper, the progress on study of zinc deficiency and immunity including the relationship between zinc deficiency and the apoptosis of T cell, B cell, the expression of MT, immunological function of red cell, and non-specific immune system were reviewed.
Animals↗
Tissue-engineered scaffolds are effective alternatives to autografts for bridging peripheral nerve gaps.
The use of autografts for "bridging" peripheral nerve gaps is limited by lack of suitable donor nerve grafts. Using a tissue-engineering approach, we have designed a three-dimensional scaffold that presents laminin 1 (LN-1) and nerve growth factor (NGF) in vivo. Semipermeable polysulfone tubes were used as carriers to introduce the tissue-engineered scaffolds to a 10-mm sciatic nerve gap in adult rats. Two months after implantation, the gross morphology of the regenerated nerve, the success rate of regeneration, and the total number and density of myelinated axons in the tissue-engineered scaffolds matched that observed in autografts. LN-1- and NGF-containing scaffolds performed comparably to autografts when functional measures that include the relative gastrocnemius muscle weight and the sciatic functional index were quantified. Our results demonstrate that tissue-engineered scaffolds match the performance of autografts in an in vivo model of peripheral nerve regeneration, raising the possibility of the scaffolds being used clinically instead of scarce autografts.
Animals↗