Articular cartilage as a load-bearing connective tissues may often be caused defects by trauma,sports, degenerative or age-related diseases. As articular cartilage has a limited inherent repair capacity, a large variety of treatment approaches including autologous chondrocyte transplantation, microfracture and mosaicplasty methods have been developed. However, there are limitations in these strategies especially when using autologous chondrcytes. Mesenchymal stem cells are considered the most promising seed cells in the study of tissue engineered cartilage. This review focuses on the induction of mesenchymal stem cells into chondrocytes in vitro and their application in cartilage repair.

ObjectiveTo study the feasibility of analyzing photosensitizers absorbing process by cells based on image processing technology.MethodsFluorescence images of Laryngeal cells were taken by inverted fluorescence microscope after adding photosensitizers for a certain time.Parameter L that reflects the fluorescence intensity of cells in different times was obtained and the calculation results were compared.ResultsThe fluorescence intensity of cells increased over time.Sobel operater and Otsu algorithm can both reflect the fluorescence intensity of images.ConclusionImage processing technology can effectively analyzes the process of photosensitizers absorbed by cells.

ObjectiveMatching pursuit algorithm(MAP),for its good parametric characterization,was applied in epileptic electroencephalography(EEG) to study time-frequency distribution.MethodsSimulation experiment of time-frequency analysis was carried out to verify the matching pursuit algorithm s superiority on frequency resolution and parametric characterization.Fourier transform,Wigner-Ville distribution and matching pursuit algorithm were applied to the time-frequency analysis on normal EEG and epileptic EEG to study epileptic discharge in the time-frequency plane and the results were compared.ResultsSimulation results showed that the matching pursuit algorithm obtained a better time-frequency distribution.Distributions of epileptic EEG and normal EEG had significant difference in time-frequency plane.ConclusionTime-frequency analysis based on matching pursuit can better reveal the EEG characteristics.

Objective Although chitosan has excellent biocompatibility and biodegradability, it is only soluble in acid solution that is not feasible for application in tissue engineering. The current study is aimed to prepare the carboxymethyl chitosan (CMC) for the purpose of improving the solubility of chitosan to meet the requirement of development of tissue engineering scaffolds. Methods The preparation methods and process conditions, such as the proportion of reactant, reaction temperature, reaction time and so on for three types of carboxymethyl chitosan were studied. Results The results indicated that optimal process conditions of three types of water soluble chitosan were obtained. Conclusion Water solubility of chitosan is greatly improved through carboxymethyl modification, which provides possibilities and foundation for further research.

Objective To construct an injectable controlled delivery system of paclitaxel based on thermosensitive PCL1250-PEG1500-PCL1250 hydrogels. Methods A thermosensitive PCL1250-PEG1500-PCL1250 triblock copolymer was synthesized by ring-opening polymerization of e-CL using PEG (Mw=l 500) as the initiator and Sn(Oct)2 as the catalyst. The synthesized PCL1250-PEG1500-PCL1250 copolymers were characterized for their composition,structure, and molecular weight via 1H NMR and GPC techniques. A series of Paclitaxel loaded hydrogels with various predesigned hydrogel concentrations and initial drug loadings were prepared to investigate their gelation ability, in vitro drug release behavior and in vivo biodegradability. Results The results calculated from 1H NMR and GPC indicated that EG/CL ratio(1.55) was consistent with the initial feed ratio(1.6), which offered a strong proof to their composition and molecular structure. The thermosensitive PCL1250-PEG1500-PCL1250 hydrogels exhibited a desirable sol-gel transition ability within the concentration range of 15%-30%. The in vitro release rate of paclitaxel from the paclitaxel/PCL1250-PEG1500-PCL1250 hydrogels was controllable by altering the hydrogel concentrations and initial drug loadings. The PCL1250-PEG1500-PCL1250 hydrogels showed a good in situ gelation ability after subcutaneously injected into mouse back. The in situ formed hydrogels gradually degradated with time and almost disappeared after 45 days in vivo. Conclusion Both the controllable drug release behavior and promising biodegradability of this new thermosensitive PCL1250-PEG1500-PCL1250 hydrogels paved a way to develop a novel delivery system for paclitaxel.

MR-T1ρ imaging is one of the novelest MRI techniques in recent years,T1ρ relaxation mainly reflect the interaction between water molecules and the surrounding macromolecu]es.Due to the unique point of view,the technique has been used to investigate a variety of pathological mechanisms in early stage of diseases,such as the content of collagen protein in articular cartilage,neuron apoptosis in neurodegenerative diseases and so on,which provides a new tool for detecting lesions in ultra-early stage or the evaluation of treatment effect.

As one of the most sensitive cells of endoplasmic reticulum stress,pancreatic βcells have an abundance of endoplasmic reticulum .It is the adaptive response of pancreatic β cells under Endoplasmic reticulum stress conditions.Internal and external factors in the environment such as oxidative damage,lipid toxicity and the effect of cytokines in the endoplasmic reticulum could breake the steady-state,resulting in barriers to folding or misfolding of protein,thereby to trigger endoplasmic reticulum stress.Serious and lasting stress will lead to β cell apoptosis,involved in a variety of metabohc diseases as well as a variety of diseases.This article gives a review on the injury effects of multi-factor induced endoplasmic reticulum stress on the pancreatic β-cell

Nanopore single molecule sequencing(SMS) is considered as one of the most promising third generation DNA sequencing method by virtue of fast sequencing and low cost. As the most significant part of the sequencing system, the synthetic solid nanopore has recently been the research highlight in the field of nanopore DNA sequencing because of its fine-controlled size, high reliability and wide applicability. Also, its fabrication method is currently one of the main challenges in this field. In this article, the principles of the nanopore SMS are introduced followed by the review of the difficulties and challenges in the current research stage with emphasis on the nanopore fabrication methods.

Mesenchymal stem cells(MSCs), which can be introduced in brain tissue by the strategies of brain parenchyma, blood and neurolymph transplantation, to repair tissue injury and promote functional recovery of neural system, have been considered as the ideal seed cells for the treatment of central nervous system diseases. However, as the special structure exists in the blood-brain barrier, study on correlation between MSCs and blood-brain barrier permeability will make it possible for more MSCs to pass the barrier to perform the treatment. This paper gives a review on the latest research development in the field.

The concept of hemangioblast was proposed a century ago. The existence of hemangioblasts has been demonstrated recently in vitro by differentiation of mouse and human embryonic stem (ES) cell into em-bryoid bodies(EBs). In the developing embryo, a common progenitor, termed "hemangioblast", generates both hematopoietic and endothelial cell lineages. The in vitro differentiation of embryonic stem cells to hemangioblast is a powerful approach for studying the commitment of the hematopoietic and endothelial lineages. This review will summarize recent development in the studies on hemangioblast.