Peripheral nerve injury is very common in clinics. It has brought the patients with high rate of disability and huge economic burden and become one of serious health problems in the world. Nowadays, with the development of nerve tissue engineering, it provides new method for surgical procedures of nerve defects repair.The nerve scaffold plays a vital role in repairing nerve defects. It can provide temporary support for nerve cells to grow,adhere and to form structures. This review aims at introducing classification, properties and the applications of the nerve scaffolds for tissue engineering. Future development of the nerve scaffolds and remaining problems are discussed as well.

The gene silence induced by small interfering RNA (siR N A) provides a powerful tool for gene therapy of neoplasm. However, safe and efficient delivery of exogenous siRNA is still the key issue for clinical application. Polyethyenimines ( PEI ) and its copolymers can encapsulate siRNA into complex in the formation of nanoparticle wherein the stability and activity of siRNA are closely related to the structure and molecular weight of PEI, N/P ratio, and the composition of copolymers.The siRNA-encapsulated nanoparticles can effectively inhibit the proliferation of tumor cell not only in vitro, but also in vivo by administration via intratumoral,intraperitoneal or venous injections.

Effective loading and site-specific delivery of growth factors to regulate the cell growth on scaffold is one of the key issues of tissue engineering. Polymeric nanoparticle is one of the candidate carriers for carrying growth factors. This article attempts to introduce the biological characteristics of growth factors commonly used in tissue engineering, polymer materials for carrying the growth factors and the preparation of the nanoparticles and delivery systems. The advantages and disadvantages of different preparations are also discussed to facilitate the selection of the appropriate methods and materials. Relevant research progress and application potentials are discussed ss well.

Object High overlap of data window is essential to improve axial resolution in elastogaphy.However, correlated errors in displacement estimates increase dramatically with the increase of the overlap, and generate the so-called "worm" artifacts. This paper presents a wavelet shrinkage de-noising in strain estimates to reduce the worm artifacts at high overlap. Methods Each of axial strain A-lines was decomposed using discrete wavelet transformation up to 3 levels. The high frequency components of every levels of wavelet coefficients were quantified by using soft threshold function according to different adaptive thresholds. Then the discrete wavelet reconstruction were performed to produce a wavelet shrinkage denoised strain line. Results The simulation results illustrated that the presented technique could efficiently denoise worm artifacts and enhance the elastogram performance indices such as elastographic SNRe and CNRe. Elastogram obtained by wavelet denoising had the closest correspondence with ideal strain image. In addition, the results also demonstrated that wavelet shrinkage de-noising applied in strain estimates could obtain better image quality parameters than that apphed in displacement estimates. The elastic phantom experiments also showed the similar elastogram performance improvement. Conclusion Wavelet shrinkage de-noising can efficiently denoise the worm artifacts noise of elastogram and improve the performance indices of elastogram while maintaining the high axial resolution.

It is confirmed that the adult cells can be re-programmed to embryonic stem cells(ESCs) by presenting some certain factors in oocytes in the clone process of animals. In recent years, some transcription factors that can induce pluripotent stem cells(iPS) have been identified and which made it possible to obtain induced pluripotent stem cells similar to embryonic stem cells. iPS provides a unique platform to study the pluripotent mechanism and to establish some specific disease models. This major scientific discovery can not only avoid the use of ES which involves ethics debate, but also lead the stem cell research to a new field.

Objective In the treatment of tumor with high intensity focused ultrasound (HIFU),the acoustic pressure distribution determines the safety and reliability of HIFU.It is necessary to predict the acoustic field produced by HIFU transducer.Methods To analyze the acoustic pressure distribution of HIFU generated by different excitation frequency and variable incentive power,comparison was made between the acoustic pressure simulated by finite difference time domain (FDTD) method and the ones measured by experiments.ResultsThe resultsshowed that the pressureat focalpoint increasedwiththe increasing of excitation power,while the change in the focal length was negligible.The focal point moved towards the transducer with the frequency increasing until the maximum sound pressure was gained at the resonant frequency (RF).Conclusion The simulation results are consistent with the experiment results,indicating that the acoustic fields can be predicted by simulation.

Objective To investigate the impact of chitosan and alkylated chitosan DNA nanoparticles on the function of human naive CD4+T cells.Methods The secretion of cytokines (IL-4 and TNF-γ) was observed after the co-incubation of human naive CD4+T cells with nanoparticles 12 h,24 h and 48 h,respectively.ResultsNone of the nanoparticles induced the production of cytokines ( IL-4 and TNF-γ ).Conclusion Chitosan and alkylated chitosan DNA nanoparticles will not induce the differentiation of human naive CD4+ T cells into T1 or T2 and may be considered as a safe gene carrier.

ObjectiveTo evaluate the inhibitive effect of Photodynamic therapy (PDT) with different parameters on dental caries formation in rats.MethodsWistar rats were infected with S.mutans to establish the rat caries mode 1.The rat's teeth were treated with 0.9% NS and 0.2% NaF as controls;laser,photosensitizer and laser plus photosensitizer,respectively as treated groups.Hematoporyrin monomethyl ether(HM ME) was used as photosensitizer and laser as the light source.The rats were sacrificed after five weeks.Keyes count was used to measure the inhibitory effect of PDT on dental caries.The surface morphology of the teeth was evaluated by scan electronic microscopy(SEM).Results The PDT-treated group and NaF-treated group showed significantly reduced Keyes scores compared with the negative controls (P＜0.05).The laser-treated group,photosensitizer-treated group and NS-treated group showed no significantly reduced Keyes scores compared with the negative controls (P＜0.05).The differences of Keyes scores between various parameter PDT treated groups were significant (P＜0.05).Additionally,Keyes scores reduced gradually with the increasing of laser power.The outcome of SEM showed that the teeth treated with different laser powers exhibited different changes in morphology.Conclusion HMMEPDT had significant inhibitive efficacy on caries development in rats and its inhibitory effect presented close correlation with the power of laser,which indicates that it is important to apply appropriate power in clinical treatment.

Objective The aim of this study was to observe the outcome and evaluate the clinical efficacy of pulsed electromagnetic fields (PEMF) on pain management in patients with osteoporosis.MethodsA total of 58 patients with osteoporosis were treated with PEMF stimulation.Pains as main indicators of their symptom were evaluated before and after treatments.The clinical outcomes were assessed by observing the visual analogue scale (VAS).Statistical analysis was carried out to support the data.Results After PEMF treatment,the patients exhibited significant pain relief from mean VAS of 6.97±1.83 to 3.36±1.69(t-test,P＜0.05 ).Of the 58 patients,28 obtained significant symptom alleviation and 18 obtained moderate symptom alleviation,while 8 obtained slight alleviation,indicating the total clinical efficacy of 93%(54/58).Conclusion The current study provides the clinical outcomes indicating that PEMF may help to release the pain from primary osteoporosis and it might be an applicable supplementary treatment method for the osteoporosis related pain.

Objective To investigate the correlation of intima-media thickness (IMT) of the lower peripheral arteries and maximal shear rate (SR) in diabetic (DM) patients and to analyze the related risk factors.Methods A total of 84 diabetic patients and 46 controls were recruited in the study.Color Doppler ultrasonography technique was applied to observe the IMT,diameter(D) and hemodynamics of the lower peripheral arteries and the comparison with biochemical parameters was carried out in order to reveal their correlation to the pathological changes of vascular in DM patients.ResultsIn DM group,the SR was lower than that in control group (P＜0.05).The risk factors related to the lower peripheral arteries of DM patients also were significant difference to that of control group (P＜0.05).Conclusion The decrease of SR in diabetes patients can cause the thicker IMT,which is one of the important factors leading to atherosclerosis and is correlated to various risk factors for metabolic syndrome.