[From Passive Application to Active Design -Restructuring and Reshaping of Core Specialty Knowledge Systems of Biomedical Engineering (Biomedical Materials Track) Undergraduate Education].

Biomedical engineering (BME) (biomedical materials track) is a typical field of interdisciplinary integration. Its specialty education simultaneously undertakes the duo reformation responsibilities for the new engineering education and the new medical education due to its unique strengths in interdisciplinary nature, comprehensive scope of knowledge, and status of being on the cutting edge of technology. We made an analysis, in this paper, of the opportunities and challenges faced by BME (biomedical materials track) specialty education on the basis of the trends and frontiers of development in biomedical materials in the world. From the perspective of new requirements raised by major national strategies and industrial development for the qualifications and competence of professionals specializing in biomedical materials, thorough reflections were made on the specialized education of BME (biomedical materials track) under the background of the new engineering education and the new medical education. Furthermore, we proposed herein to reconstruct the specialized core knowledge system according to the main line of the reactions and the responses between the biomedical materials and human bodies at different levels and set up a series of courses of biomedical materials science centered on Materiobiology as the core. We also proposed to establish a diversified integrated reform model of the training system incorporating production, learning, research and application for highly competent BME (biomedical materials track) professionals. This paper attempts to contribute to the solution of the major issue of how to train the innovative talents and leaders who will pioneer a new round of diagnosis and treatment technology revolution and the development of the medical device industry.

Graphene oxide-composited chitosan scaffold contributes to functional recovery of injured spinal cord in rats.

The study illustrates that graphene oxide nanosheets can endow materials with continuous electrical conductivity for up to 4 weeks. Conductive nerve scaffolds can bridge a sciatic nerve injury and guide the growth of neurons; however, whether the scaffolds can be used for the repair of spinal cord nerve injuries remains to be explored. In this study, a conductive graphene oxide composited chitosan scaffold was fabricated by genipin crosslinking and lyophilization. The prepared chitosan-graphene oxide scaffold presented a porous structure with an inner diameter of 18-87 µm, and a conductivity that reached 2.83 mS/cm because of good distribution of the graphene oxide nanosheets, which could be degraded by peroxidase. The chitosan-graphene oxide scaffold was transplanted into a T9 total resected rat spinal cord. The results show that the chitosan-graphene oxide scaffold induces nerve cells to grow into the pores between chitosan molecular chains, inducing angiogenesis in regenerated tissue, and promote neuron migration and neural tissue regeneration in the pores of the scaffold, thereby promoting the repair of damaged nerve tissue. The behavioral and electrophysiological results suggest that the chitosan-graphene oxide scaffold could significantly restore the neurological function of rats. Moreover, the functional recovery of rats treated with chitosan-graphene oxide scaffold was better than that treated with chitosan scaffold. The results show that graphene oxide could have a positive role in the recovery of neurological function after spinal cord injury by promoting the degradation of the scaffold, adhesion, and migration of nerve cells to the scaffold. This study was approved by the Ethics Committee of Animal Research at the First Affiliated Hospital of Third Military Medical University (Army Medical University) (approval No. AMUWEC20191327) on August 30, 2019.

[Raman spectrum study of the calcium phosphate glass structure affected by the addition of TiO2].

Calcium phosphate glasses in which part of CaO was replaced by TiO2 were prepared by the conventional melt quench method. The structures and their thermal properties were studied by XRD, Raman and DSC techniques. The results show that, TiO2 and calcium phosphate form homogeneous glass with the amount of the additive less than 3 mol%. The glasses matrix generates a Ca2P2O7 and CaTi4 (PO4)6 crystal phase with the amount of the additives in the range of 6-12 mol%. With the addition of TiO2, the structural changes of the glass system are from metaphosphate to pyrophosphate and orthophosphate. With the TiO2 less than 3 mol%, the cohesion of the glasses structure and the glasses thermal stability is enhanced, and the glasses transition temperature is gradually increased.

[Raman spectra analysis of calcium metaphosphate glass-ceramics].

In the present paper, calcium metaphosphate glass with molar ratio of Ca/P = 0.45 was prepared and Ca(PO3)2 glass-ceramics were obtained by reheating the glass at 300-700 degrees C. The Raman spectra of samples were measured. The bands of these Raman spectra were assigned and analyzed. The length of P-O bonds was calculated by using Raman wavenumbers. The results show that the crystal phase in glass was obtained when preserved at 300 degrees C for 3 h; Along with temperature increase, upsilon(s) (PO2) and upsilon(s) (POP) bands are stable in frequency, the bands intensity increases and fine structure appears in the Raman spectra fingerprint. The crystallization degree of glass-ceramics surface is higher than the inner. The length of P-O bonds changes during the heating process and crystallization. The length of O--P--O chain bonds changes to 158.27 pm from 159.96 pm, and terminal P--O changes to 149.02 pm from 147.92 pm, when Ca(PO3)2 glass becomes beta-Ca(PO3)2 crystal.

[Synthesis of the CaCO3:Eu3+ red phosphor by microwave method].

The red phosphor of CaCO3 doped with Eu3+ was synthesized with the microwave method in the aqueous solution and characterized with electron microscope (SEM), X-ray diffraction (XRD), and photoluminescence and photoluminescence excitation (PL-PLE) spectrum. Also under investigation was the influence of microwave power on luminescence properties. The results showed that the synthesized CaCO3:Eu+ particles were the mixture of various particles in the forms of vaterite with flower-flake, calcite with cubic shape and aragonite with needle-like, which were evenly dispersed. The Eu3+ ion as the luminescent center inhabited the site of Ca3+ in mixed phases of CaCO3:Eu3+. This feature was mainly characterized by the intense charge transfer band range from 200 to 300 nm in the PLE spectrum, which was the wide band excitation. Moreover, the narrow excitation peaks at 319, 395, 465, 535 nm and so on could be detected in the PLE spectrum. For the mixed phase, the magnetic-dipole transition (5)D0 to (7)F1 emission was split into two sublevels at about 589 and 593 nm by the crystal field. The mainly emission peaks were located in the vicinity of 614 and 620 nm, corresponding to the electric dipole transition (1)D0-->(7)F2 of Eu3+ ions that was the pure red emission. Moreover, with the improvement of the microwave power, the emission intensity was on rise for the morphology and phase of the sample changed from the flower-flake vaterite to the needle-like aragonite, coupled with the intensity of red light emission.

Research on the additives to reduce radioactive pollutants in the building materials containing fly ash.

Several kinds of functional additives such as barite, zeolite, ferric oxide, gypsum, and high alumina cement were introduced to prepare a low-radiation cement-based composite to reduce radioactive pollutants contained in fly ash. The effect of content and granularity of the functional additives on the release of radioactive pollutants were investigated. Composites were characterized by X-ray diffraction, Scan electron microscopy. The results indicate that the radioactive pollutants contained in the fly ash can be reduced by adding a proper amount of zeolite, ferric oxide, gypsum, and high alumina cement. The release of radon from fly ash decreases with a decrease in the granularity of additives. Compared with traditional cement-based composite containing fly ash, the release of radon can be reduced 64.8% in these composites, and the release of gamma-ray is decreased 45%. Based on the microstructure and phase analysis, we think that by added functional additives, there are favorable to form self-absorption of radioactivity in the interior composites. This cement-based composite will conducive to fly ash are large-scale applied in the field of building materials.

[Controlled release of paclitaxel from microparticles containing PLLA and its anti-tumor activity on human ovarian carcinoma cell line].

OBJECTIVE: To prove the PLLA-PTX' efficacy on growth, apoptosis of ovarian cancer cell line SKOV3, and to study the controlled release roles of PLLA for PTX. METHODS: Cultured cells of human ovarian Carcinoma cell Line SKOV3 were treated with PLLA-PTX microparticles and PTX only separately, untreated cells as the control. The proliferation of SKOV3 cells were determined by MTT assay with the morphologic change observed under inverted phase contrast microscope, the apoptosis of cell were demonstrated by FCM and in situ TUNEL technique. RESULTS: The anti-tumor activity of PLLA-PTX microparticles was stronger than PTX alone. A time-dependent and dose-dependent growth inhibition was abserved. At 0.05 micromol/L drug concentration, SKOV3 cell viability experiment demonstrated that the drug formulated in the microparticles was more effective than that formulated in PTX. PLLA-PTX microparticles can increase G2/M period percentage, interrupt the cell cycle proceeding, and inhibit the tumor cells'growth through cell apoptosis. Positive staining for the presence of apoptosis were obtained in SKOV3 cells with PLLA-PTX microparticles. CONCLUSIONS: PLLA-PTX microparticles have strong anti-tumor activity and obviously controlled released effectiveness. It shows longer and stronger controlled anti-tumor activity than paclitaxel alone.

Development of Fe3O4-poly(L-lactide) magnetic microparticles in supercritical CO2.

The Fe(3)O(4)-poly(L-lactide) (Fe(3)O(4)-PLLA) magnetic microparticles were successfully prepared in a process of solution-enhanced dispersion by supercritical CO(2) (SEDS), and their morphology, particle size, magnetic mass content, surface atom distribution and magnetic properties were characterized. Indomethacin (Indo) was used as a drug model to produce drug-polymer magnetic composite microparticles. The resulting Fe(3)O(4)-PLLA microparticles with mean size of 803 nm had good magnetic property and a saturation magnetization of 24.99 emu/g. The X-ray photoelectron spectroscopy (XPS) test indicated that most of the Fe(3)O(4) were encapsulated by PLLA, which indicated that the Fe(3)O(4)-PLLA magnetic microparticles had a core-shell structure. After further loading with drug, the Indo-Fe(3)O(4)-PLLA microparticles had a bigger mean size of 901 nm, and the Fourier transform infrared spectrometer (FTIR) analysis demonstrated that the SEDS process was a typical physical coating process to produce drug-polymer magnetic composite microparticles, which is favorable for drugs since there is no change in chemistry. The in vitro cytotoxicity test showed that the Fe(3)O(4)-PLLA magnetic microparticles had no cytotoxicity and were biocompatible, which means there is potential for biomedical application.

Study of poly(L-lactide) microparticles based on supercritical CO2.

Poly(L-lactide) (PLLA) microparticles were prepared in supercritical anti-solvent process. The effects of several key factors on surface morphology, and particle size and particle size distribution were investigated. These factors included initial drops size, saturation ratio of PLLA solution, pressure, temperature, concentration of the organic solution, the flow rate of the solution and molecular weight of PLLA. The results indicated that the saturation ratio of PLLA solution, concentration of the organic solution and flow rate of the solution played important roles on the properties of products. Various microparticles with the mean particle size ranging from 0.64 to 6.64 microm, could be prepared by adjusting the operational parameters. Fine microparticles were obtained in a process namely solution-enhanced dispersion by supercritical fluids (SEDS) process with dichloromethane/acetone mixture as solution.

Facial pain induces the alteration of transient receptor potential vanilloid receptor 1 expression in rat trigeminal ganglion.

OBJECTIVE: To investigate the involvement of transient receptor potential vanilloid receptor 1 (TRPV1) in the facial inflammatory pain in relation to thermal hyperalgesia and cold pain sensation. METHODS: Facial inflammatory pain model was developed by subcutaneous injection of turpentine oil (TO) into rat facial area. Head withdrawal thermal latency (HWTL) and head withdrawal cold latency (HWCL) were measured once a day for 21 d after TO treatment using thermal and cold measurement apparatus. The immunohistochemical staining, cell-size frequency analysis and the survey of average optical density (OD) value were used to observe the changes of TRPV1 expression in the neurons of the trigeminal ganglion (TG), peripheral nerve fibers in the vibrissal pad, and central projection processes in the trigeminal sensory nuclei caudalis (Vc) on day 3, 5, 7, 14, and 21 after TO injection. RESULTS: HWTL and HWCL decreased significantly from day 1 to day 14 after TO injection with the lowest value on day 5 and day 3, respectively, and both recovered on day 21. The number of TRPV1-labeled neurons increased remarkably from day 1 to day 14 with a peak on day 7, and returned back to the normal level on day 21. In control rats, only small and medium-sized TG neurons were immunoreactive (IR) to TRPV1, and the TRPV1-IR terminals were abundant in both the vibrissal pad and the Vc. Within 2 weeks of inflammation, the expression of TRPV1 in small and medium-sized TG neurons increased obviously. Also the TRPV1 stained terminals and fibers appeared more frequent and denser in both the vibrissal pad skin and throughout laminae I and the outer zone of laminae II (IIo) of Vc. CONCLUSION: Facial inflammatory pain could induce hyperalgesia to noxious heat and cold stimuli, and result in increase of the numbers of TRPV1 positive TG neurons and the peripheral and central terminals of TG. These results suggest that the phenotypic changes of TRPV1 expression in small and medium-sized TG neurons and terminals might play an important role in the development and maintenance of TO-induced inflammatory thermal hyperalgesia and cold pain sensation.

[Preparing of Al2O3/ZrO2 composite dental ceramics through isostatic pressing technology].

OBJECTIVE: To find out how to prepare high-density dental ceramics through isostatic pressing so that sintering shrinkage will be reduced. METHODS: To prepare Al2O3/ZrO2 composite powder first, then to mold through dry-pressing, and to shape the green-body through isostatic pressing. The green-bodies were sintered at the temperature of 1 400 degrees C and kept at the temperature for different period of time (2 h, 3 h, 4 h). After that, the density and fracture strength were measured and the microstructure observed by scanning electron microscope (SEM). RESULTS: The sample product's density, line-shrinkage, and fracture strength of ceramics was rising with the sintering time lengthened. The sample product kept under the temperature of 1 400 degrees C for 4 hours, the fracture strength was (497.27 +/- 78.45) MPa and glass phase distributed evenly in the ceramics and the grains were integrated owing to the glass phase. The longer the sintering time, the more even the microstructure was. CONCLUSION: The sintering quality and the efficiency were improved through isostatic pressing.

Characterization of three types of ATP-activated current in relation to P2X subunits in rat trigeminal ganglion neurons.

In the present study, ATP-activated currents (I(ATP)s) recorded from rat trigeminal ganglion (TG) neurons using whole-cell patch clamp technique are classified into three types (F, I and S) based on the characteristics of their activation and desensitization. The time of rising phase (R(10-90)) of types F, I and S of I(ATP) is measured to be 33.6+/-4.5, 62.2+/-9.9 and 302.1+/-62.0 ms respectively, and positively correlated to cell size. The time of decaying phases (D(10-90)) of types F and S is 399.4+/-58.2 and >1500 ms, respectively. The dose-response curves for the three types of I(ATP) show that their EC(50) values are close (3.44 x 10(-5), 4.89 x 10(-5) and 4.14 x 10(-5) M for types F, I and S respectively, P>0.05). Their reversal potentials are basically the same, varying from +4 to +10 mV. In addition, using whole-cell patch clamp technique in combination with single cell immunohistochemical staining for P2X receptor subunits, our results suggest that the type distinction of ATP-activated current was associated with cell size and P2X receptor subunits: small-sized cells with type F of I(ATP) express only P2X1 and/or P2X3 subunits, while cells with types S and I of I(ATP) express P2X2 or P2X4 in addition to P2X1 and P2X3.

Characteristics of P2X purinoceptors in the membrane of rat trigeminal ganglion neurons.

The characteristics of purinoceptors in the membrane of rat trigeminal ganglion (TG) neurons were studied by using whole- cell patch clamp technique. The results showed that most of neurons examined (78.9%, 142/180) were responsive to ATP in a concentration-dependent manner; the others (21.1%, 38/180) were ATP insensitive. Of the ATP-sensitive cells, the majority (95.1%, 135/142) responded to ATP with an inward current, a few (2.1%, 3/142) with an outward current, and the rest (2.8%, 4/142) with biphasic current. Small sized cells (<30 mum) responded to ATP with a rapid desensitizing inward current and were highly sensitive to vanilloid; the medium sized cells (30~40 mum) responded to ATP with slow desensitizing inward current and were not sensitive to vanilloid; while the majority of large sized cells (>40 mum) did not respond to ATP and vanilloid. The waveform of ATP-activated inward currents was related to the cell diameter. The I-V curves for both small and medium sized cells manifested obvious inward rectification. Furthermore, we studied the kinetic features of ATP-activated currents and the effects of P2 purinoceptor agonists and antagonists on I(ATP). The findings suggest that ATP receptor-ion channels are expressed differently among different types of rat TG neurons.

The comparisons on total RNA from different source-original neurons applied in LMPC.

Objective To compare the quality and quantity of total RNA from different source-original neurons applied in LMPC technique. Methods (1) Aglient 2100 bioanalyzer and RT-PCR were used to check the concentration and fragmentation of total RNA from unfixed, temporal fixed and fixed 12 h hypothalamus sections; (2) Different neurons of PVN and SON were collected by LMPC, CRH, TRH, AVP, OT mRNA level were measured by RT-PCR; (3) Labeled neurons by injecting CTB into stomach and non-labeled neurons in DMV collected by LMPC were checked for house keeping genes by RT-PCR. Results (1) Unfixed section had higher concentration and better quality of total RNA compared with fixed sections applied in LMPC; relative short amplicons such as GAPDH, NSE, MCH and MC4R were successfully obtained from fixed and unfixed and long amplicon of GR can only be obtained from unfixed material; (2) In mangocellular PVN and SON the expressions of AVP and OT were more special than those in the parvocellular PVN. Oppositely, the expressions of CRH, TRH in the parvocellular were more special than the other two; (3) The expressions of house keeping genes had no significant difference between labeled and non-labeled DMV neurons. Conclusion The quality and quantity of total RNA from unfixed brain tissues were better than fixed tissues applied in LMPC and the CTB tracer which may differentiate neurons had no significant effect on physiology of the neurons applied in LMPC. The results showed that the LMPC technique is suitable for the qualitative and quantitative study on individual neurons at mRNA level.

Effects of tanshinone on neuropathological changes induced by amyloid beta-peptide(1-40) injection in rat hippocampus.

AIM: To investigate the effect of tanshinone (Tan) on the neuropathological changes induced by amyloid beta-peptide1-40 (Abeta1-40) injection in hippocampus in rats. METHODS: Abeta1-40 10 microg was injected bilaterally into the dorsal blade of the dentate gyrus in the hippocampus. The level of acetylcholinesterase (AChE) in hippocampus was evaluated by histochemistry. The expressions of neuronal nitric oxide synthase (nNOS) and inducible form of NOS (iNOS) were detected by immunohistochemistry and Western blot. Abeta1-40-injected rats were treated ig with Tan, the major active ingredient from Salvia miltiorrhiza of Chinese herb extract. RESULTS: The level of AChE positive fibers of each subfield in Abeta1-40-injected hippocampus decreased significantly compared with those of control (P<0.01). The expression of nNOS was down-regulated whereas the iNOS was up-regulated. After treatment with Tan (50 mg/kg, ig), the changes mentioned above were significantly improved. Moreover, the correlation analysis revealed a significant negative correlation between the area percentage of AChE positive fibers and the number of iNOS positive neural cells in CA1, CA2 to CA3 (CA2-3), and dentate gyrus (DG) subfields (P<0.01). CONCLUSION: Tan can protect the neuropathological changes induced by Abeta1-40 injection in hippocampus.

Quantitative analysis of sinoatrial node using Doppler tissue images.

A method has been developed to quantitatively analyze sinoatrial nodes (SAN) using Doppler tissue images (DTI). Doppler tissue images of SAN are acquired using an intracardiac catheter via the superior vena cava in an in vivo experiment. A sequence of DTI images of a SAN is obtained, and a complete cycle of the SAN excitation is observed. The tissue acceleration of the SAN is extracted and quantitatively analyzed. The estimated time-acceleration curve of the SAN exhibits remarkable similarity to the electrocardiogram curve. This is the first report on such finding. The experimental results show that the tissue movement of the SAN correlates with electrical cardiac activities and closely associates with the different phases of the cardiac cycle. This method has great potential in characterizing the local cardiac activities through the study of the conduct pathway.

Enzymes activity of intestinal grafts after liver small bowel transplantation in rats.

OBJECTIVES: To investigate the activity alterations of enzymes in intestine grafts after liver/small bowel transplantation in rats and the relations of these changes to immune rejection of grafts. METHODS: A model of liver/small bowel transplantation (LSBT) was established in closed colony SD and Wistar rats. The activity of enzymes including triphosphatase (ATPase), alkalinophosphatase (AKP), acytelcholinesterase (AchE), oxidesynthase (NOS) and monoamine oxidase (MAO) in bowel grafts was studied histochemically at regular postoperative intervals. RESULTS: The activity of enzymes in the wall of the grafts disappeared eventually in isolated small bowel transplantation (SBT) rats. In contrast, the activity in LSBT rats remained and recovered postoperatively. CONCLUSIONS: The rejection in grafted intestine could be prevented or delayed in LSBT rats. The changes in the activity of enzymes and neurons might be used to detect the rejection and function of the graft.