[Preparation and Characterization of Manganese and Fluorine Co-Modified Hydroxyapatite Composite Coating].

Titanium and titanium alloys have been widely used as orthopedic, dental implants and cardiovascular stents owing to their superior physical properties. However, titanium surface is inherently bio-inert, thus could not form efficient osseointegration with surrounding bone tissue. Therefore, to improve the surface property of titanium implant is significantly important in clinical application. Manganese and fluorine co-doped hydroxyapatite (FMnHAP) coatings were prepared on titanium substrate by electrochemical deposition technique. The as-prepared coatings were examined by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) tests. The results indicated that the FMnHAP coatings take the morphology of nanoscale-villous-like, the composite coating becomes more compact. The FTIR test indicated that the symmetry of bending vibration modes of hydroxyl changed, simulated body fluid immersion test proved that the FMnHAP coatings had induce carbonate-apatite formation, indicating that the composite coating possess excellent biocompatibility. In the electrochemical corrosion testing, the FMnHAP coatings showed stronger corrosion resistance than pure Ti.

[Preparation of chitosan/strontium-substituted hydroxyapatite films on titanium and its FTIR characteristics].

Chitosan/strontium-substituted hydroxyapatite (CHI/SrHAP) coatings were prepared on titanium substrate by electrochemical deposition technique containing Sr2+, Ca2+, PO4(3-) and Chitosan. The as-prepared coatings were examined by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) tests. The results indicate that the CHI/SrHAP coatings take the morphology of flake-like rather than the needle-like crystal , and the composite coating becomes more compact. The FTIR test indicates that the typical vibration absorption peaks of chitosan (amide I and amide II) emerged, simulated body fluid immersion test proved that the CHI/SrHAP coatings had induced carbonate-apatite formation, indicating that the composite coating possesses excellent biocompatibility. In the electrochemical corrosion testing, that the CHI/SrHAP coatings showed stronger corrosion resistance than pure Ti.

[Study of adsorption and desorption of behaviors of Pb2+ on thiol-modified bentonite by flame atomic absorption spectrometry].

A comparative analysis of the functional groups and surface structure of the Ca-bentonite (RB) and thiol-modified bentonite (TMB) were characterized by means of FTIR and SEM. The absorptive property of Pb2+ on TMB and RB and its influential factors was studied and the conditions for the adsorption were optimized by using FAAS method. Then the conditions for desorption of Pb2+ from the TMB by using simulated acid rain were studied and the contrast analysis of absorptive stability of Pb2+ on TMB and RB was given. The results showed that the adsorption rate of Pb2+ by TMB could reach more than 98%, when the initial Pb2+ concentration was 100 mg.L-1, the liquid-solid ratio was 5 g.L-1, pH was 6. 0, KNO3 ionic strength was 0. 1 mol.L-1 and adsorption period was 60min at 25 C. The saturated adsorption capacity of TMB was 67.27 mg.g-1; it's much more than that of RB (9.667 mg.g-1). The adsorption of Pb2+ on TMB follows Langmuir and Freundlich isotherm models well. Desorption experiments of Pb2+ from TMB with simulated acid rain (pH 3. 50) were done, and the desorption rate was 0. The results showed that TMB has a strong adsorption and fixation capacity for PbZ+; it is adapted to lead contaminated soil for chemical remediation.

Properties of proton transfer in hydrogen-bonded systems and its experimental evidences and applications in biology.

We review the progresses of investigation of soliton theory of proton transfer along the hydrogen-bonded systems, such as protein molecules and ice, based on its features of molecular structure, and study further the properties of motion of proton-soliton and influences of anharmonic vibration and structure disorder of the systems, environmental temperature and externally applied fields on the motion of the proton-soliton. In these studies we first determine the mechanism of generation and representation of the nonlinear interactions, which results in the form of proton-soliton, give the Hamiltonian of the system, and gain the proton-soliton solutions of dynamic equations of the proton using the analytic and numerical simulation methods, respectively. At the same time, we find out the mobility and electric conductivity of the proton-soliton along the systems arising from the nonlinear interactions under action of an electric field, as well as their temperature-dependences in ice. These results in the investigations are consistent with experimental data. Thus the true occurrence of the proton-soliton excitation and the correctness of the theory are verified by the experiments. Therefore the theory of proton-soliton transfer in the systems built here is correct. Finally we utilize the nonlinear theory of proton-soliton transfer to investigate the mechanism and properties of transcript and duplication of deoxyribonucleic acid (DNA) in life systems, in which the theory of transcript and duplication are firstly established on the basis of the properties of molecular structure of DNA. The results studied show that the phenomena of transcript and duplication of DNA are explained perfectly using the theory of proton-soliton motion in the hydrogen-bonded systems. Thus we not only obtain the properties of proton-soliton but also confirm that the proton-soliton theory can be applied to elucidate the mechanism of transcript and duplication in DNA. Thus the proton-soliton theory in hydrogen-bonded systems has a wide application in physics and biology.

[FTIR spectra investigation of rat tissues exposure to infrared light].

Structure of biological molecules may change when exposure to electromagnetic field, the change can be recognized from the change of the infrared spectrum. The present paper studied microstructure of rat blood, testis and brain after its exposure to infrared light for 30 days via their FTIR characteristics within the 1 700 - 1 000 cm(-1) range, and the authors also analysed biological characteristics of tissue microstructure with infrared light exposure on rat by their second derivative spectra. Mechanisms of biological effects induced by infrared light were further explored through the findings. All the results indicate that the Fourier transform infrared spectroscopy can be used to analyze infrared light exposure for biological tissue microstructure.

[Effects of PEMF on fluorescence spectra of rats serum].

To investigate the relationship between the fluorescence spectra of serum and the brain injury effect, the alteration of fluorescence emission in serum was collected by fluotescence spectroscopy, the pathologic changes in the rat brain were obvious by histopathology after exposure to PEMF. Sprague-Dawley male rats were randomized into sham exposed and PEMFs exposed groups. After exposure to PEMF (3.5 ns rising time, 14 ns pulse width, and amplitude up to 200 kV/400 kV at 1 Hz repetitive rate) at 0.5, 1, 3, 6 and 12 h, the expression of S100B and the fluorescence spectra in serum were detected, the changes in brain morphology were observed. The results showed that the fluorescence intensity of 400 kV groups were higher than 200 kV groups at different time points after exposure to PEMF. It suggests that the extent of brain injury was associated with the pulse frequency. The trends of fluorescence spectra in serum coincide with the expression of S100B and pathologic changes. It shows that fluorescence spectroscopy could apply to analysis of the effect of brain injury after exposure to PEMF.

[Preparation of fluoridated hydroxyapatite coatings on titanium by electrolytic deposition and its FTIR characteristics].

Fluoridated hydroxyapatite coatings (FHAP) were prepared on titanium substrate by electrochemical deposition technique containing Ca2+, PO4(3-), and F(-) ions. The deposition was all conducted at a constant current of 0.9 mA for 60 min at 60 degrees C. The as-prepared coatings were examined by scanning electron microscope (SEM), energy-dispersive Xray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and Xray diffraction (XRD) tests. The results indicate that the FHAP cryatals take the morphology of nanoscale-rodlike cone rather than the micron-daisy petal, and the composite coating becomes more compact. The FTIR test indicates that the symmetry of stretching and bending vibration modes of hydroxyl changed, simulated body fluid immersion test proved that the FHAP coating had induced carbonate-apatite formation, indicating that the composite coating possesses excellent biocompatibility.

Altered expression of matrix metalloproteinases and tight junction proteins in rats following PEMF-induced BBB permeability change.

OBJECTIVE: To investigate the expression of occludin, ZO-1, MMP-2, and MMP-9 in cerebral microvasculature following Pulse Electromagnetic Field (PEMF) induced BBB permeability change. METHODS: Sprague-Dawley rats were randomized into PEMF and sham exposed groups (n = 8). After exposure to PEMF at 0.5, 1, 3, 6, and 12 h, BBB permeability was measured by Evans-Blue extravasation. The expression of occludin, ZO-1, MMP-2, and MMP-9 were detected by real-time quantitative reverse transcriptase PCR and western blotting. MMP-2 and MMP-9 activity were detected by EnzChek gelatinase assay. RESULTS: Compared with the sham group, PEMF exposure led to increased permeability of the BBB to EB, which was prolonged after exposure. BBB permeability became progressively more severe, and recovered at 6 h. The gene and protein expression of occludin and ZO-1 were significantly decreased, while MMP-2 and MMP-9 expression were significantly increased after exposure to PEMF. All levels of expression recovered 12 h following PEMF. CONCLUSION: Changes to BBB permeability were related to the alteration expression of tight junction proteins and matrix metalloproteinase after exposure to PEMF.

[FTIR spectra investigation of rat sensitive tissues exposure to ELF-EMF].

Nonthermal effects of extremely low frequency electromagnetic fields (ELF-EMF) are related to changes in the microstructure of biological tissues after exposure to electromagnetic radiation. Fourier transform infrared spectroscopy (FTIR) analysis method can effectively study the mechanisms of biological effects of electromagnetic radiation. The present paper studies the characteristics of sensitive tissues of rat after ELF-EMF exposure. FTIR analysis of sensitive tissues of control group and experimental group showed that 50 Hz, 0.75 mT ELF-EMF exposure for 20 days can affect molecular level of the rat testis, blood and brain. Experimental results show that regular changes in absorption peak positions and intensity in the spectra of sensitive tissue may be caused by exposure to ELF-EMF, therefore, Fourier transform infrared spectroscopy is an effective means to study mechanism of biological effects of electromagnetic fields.

Investigation of biological property of nanohydroxyapatite materials.

The biological effects of nanohydroxyapatites and its cell toxicity have been studied using the MTT and ALP method, infrared spectrum of absorption and electrophoresis method, respectively. The nanohydroxyapatites are prepared and made by using sol-gel method, in which the parameters of process and reaction are controlled as: pH > 9, Ca/P = 1.67, sintering temperature of 1100 degrees C and sintering time 2 hours. Studied results show that nanohydroxyapatites can interact with human serum albumin and change its second structure and weight of molecules. We find that the nanohydroxyapatites and complex of nanoHAP + nanoCrO2 can all restrain the proliferation of MG63 cells, but their toxicities are first degree or minor, the toxicity of the complex is smaller than that of pure nanohydroxyapatites.

The properties of bio-energy transport and influence of structure nonuniformity and temperature of systems on energy transport along polypeptide chains.

A new theory of bio-energy transport along protein molecules in living systems, where the energy is released by hydrolysis of adenosine triphosphate (ATP), is proposed based on some physical and biological reasons. In the new theory, the Davydov's Hamiltonian and wave function of the systems are simultaneously modified and extended. A new interaction has been added into Davydov's Hamiltonian. The wave function of the excitation state of single particles for the excitons in the Davydov model is replaced by a new wave function of two-quanta quasicoherent state. In such a case, the bio-energy is transported by the new soliton, which differs from the Davydov's soliton. The soliton is formed through self- trapping of two excitons interacting amino acid residues. The exciton is generated by vibrations of amide-I (CO stretching) arising from the energy of hydrolysis of ATP. The properties of the new soliton are extensively studied by analytical method and its lifetime is calculated using the nonlinear quantum perturbation theory and a wide ranges of parameter values relevant to protein molecules. The lifetime of the new soliton at the biological temperature 300 K is enough large and belongs to the order of 10⁻¹° s, or τ/τ0≥700, in which the soliton can transports over several hundreds amino acid residues. These studied results show clearly that the new soliton is thermally stable and has so larger lifetime that it can play an important role in biological processes. Thus the new model is a candidate of the bio-energy transport mechanism in protein molecules. In the meanwhile, the influences of structure nonuniformity in protein molecules and temperature of the systems on the states and properties of the soliton transport of bio-energy are numerically simulated and studied by the fourth-order Runge-Kutta method. The structure nonuniformity arises from the disorder distributions of masses of amino acid residues, side groups and impurities, which results also in the fluctuations of the spring constant of protein molecules, dipole-dipole interaction between the neighboring amides, exciton-phonon (vibration of amino acids)interaction, chain-chain interaction among the three channels and ground state energy of the systems. We investigated the behaviors and states of the new solitons in a single protein molecular chain and α-Helix protein molecules with three channels under influences of the structure nonuniformity. We prove first that the bio-energy is transported by a soliton, which can move without dispersion, retaining its shape, velocity and energy in a uniform and periodic protein molecule. When the structure nonuniformity exists, although the fluctuations of the spring constant, dipole-dipole interaction constant, exciton-phonon coupling constant and ground state energy and the nonuniformity distributions of masses of amino acid residues can change the states and properties of motion of new soliton, they are still quite stable and very robust against these structure nonuniformities, i.e., even there are a larger structure nonuniformity in the protein molecules, the new solitons cannot be still dispersed. If the effects of thermal perturbation of medium on the soliton in nonuniform proteins is considered again, the new soliton can transport also over a larger spacing of 400 amino acids and has a longer time period of 300 ps, it is still thermally stable up to 320 K under the influence of the above structure nonuniformities. However, the new soliton disperses in the case of a higher temperature of 325 K and in more large structure nonuniformity. Thus, we determine that the new soliton's lifetime and critical temperature are 300 ps and 320 K, respectively. These results are also consistent with analytical data obtained via quantum perturbed theory. For α-Helix protein molecules with three channels, the results obtained show that the structure nonuniformity and quantum fluctuation can change the states and features of the new solitons, for example, the amplitudes, energies and velocities of the new soliton are decreased, but the solitons have been not destroyed, they can still transport steadily along the molecular chains retaining energy and momentum. When the quantum fluctuations are larger, such as, structure disorders and quantum fluctuations of 0.67<α(K)<2, ΔW=±8%W¯, ΔJ=±1%J¯, Δ(χ1+χ2)=±3%(χ¯1+χ¯2) and ΔL=±1%L¯ and Δɛ0=ɛ|ß(n)|, ɛ=0.1 meV, |ß(n)|<0.5, the new soliton is still stable. Therefore, the new solitons are quite robust against these nonuniform effects. However, they will be dispersed or disrupted in cases of very large structure nonuniformity. When the influence of temperature on solitons is considered, we find that the new solitons can transport steadily over 333 amino acid residues in the case of a long time period of 120 ps, in which the soliton can retain its shape and energy to travel forward along protein molecules after their mutual collision at the biological temperature of 300 K. However, the soliton disperses in cases of higher temperatures 325 K under action of a larger structure disorder. Thus, its critical temperature is about 320 K. When the effects of structure nonuniformity and temperature are considered simultaneously, then the new soliton has still high thermal stability and can transport also along the protein molecular chains retaining its amplitude, energy and velocity, they will disperses in the larger fluctuations, for example, 0.67 M¯

The theory of bio-energy transport in the protein molecules and its properties.

The bio-energy transport is a basic problem in life science and related to many biological processes. Therefore to establish the mechanism of bio-energy transport and its theory have an important significance. Based on different properties of structure of α-helical protein molecules some theories of bio-energy transport along the molecular chains have been proposed and established, where the energy is released by hydrolysis of adenosine triphosphate (ATP). A brief survey of past researches on different models and theories of bio-energy, including Davydov's, Takeno's, Yomosa's, Brown et al.'s, Schweitzer's, Cruzeiro-Hansson's, Forner's and Pang's models were first stated in this paper. Subsequently we studied and reviewed mainly and systematically the properties, thermal stability and lifetimes of the carriers (solitons) transporting the bio-energy at physiological temperature 300 K in Pang's and Davydov's theories. From these investigations we know that the carrier (soliton) of bio-energy transport in the α-helical protein molecules in Pang's model has a higher binding energy, higher thermal stability and larger lifetime at 300 K relative to those of Davydov's model, in which the lifetime of the new soliton at 300 K is enough large and belongs to the order of 10(-10) s or τ/τ(0)≥700. Thus we can conclude that the soliton in Pang's model is exactly the carrier of the bio-energy transport, Pang's theory is appropriate to α-helical protein molecules.

[Effects of redox state of disulfide bonds on the intrinsic fluorescence and denaturation of Trx-fused gibberellin-induced cysteine-rich protein from Gymnadnia conopsea].

In the present paper, thioredoxin-fused gibberellin-induced cysteine-rich protein from Gymnadnia conopsea, desigated as Trx-GcGASA and expressed prokaryotically, was purified and identified by using Ni(2+) -NTA affinity chromatography column and SDS-PAGE, and then its intrinsic fluorescence was investigated in the absence and presence of dithiothreitol (DTT), oxidized glutathione (GSSG), peroxide and guanidine hydrochloride (GdnHCl) by means of steady-state fluorescence spectroscopic methods. It was found that (1) at the neutral pH Trx-GcGASA had maximum fluorescence emission at 305 nm following excitation at different wavelengths varying from 250 to 280 nm, which was ascribed to the fluorescence emission from tyrosine residues. (2) The reduction of disulphide bonds lead to the changes in the relative fluorescence intensity between tyrosine and tryptophan residues from 0.7 to 1.8. (3) Both Tyr and Trp residues underwent 12%-21% decrease in fluorescence intensity with the addition of 0.5 mmol x L(-1) GSSG or 5 mmol x L(-1) peroxide. The latter was roughly consistent with the antioxidative activity reported in vivo. (4) No matter whether 1 mmol x L(-1) DTT was absent or present, the fusion protein could not be fully unfolded with lambda(max) < 350 nm following the treatment of 6 mol x L(-1) GdnHCl. (5) Fusion protein Trx-GcGASA experienced GdnHCl-induced denaturation process, and the unfolding equilibrium curve could be well fitted by using two-state model, giving the Gibbs free energy change (deltaG) of 3.7 kJ x mol(-1). However, it was not the case for reduced Trx-GcGASA protein. The aforementioned experimental results will not only provide some guides to investigate the effects of fusion partner Trx on the unfolding thermodynamics, kinetics and refolding process of Trx-GcGASA, but also will be useful for further studies on the strucuture of GA-induced cysteine-rich protein with the help of spectroscopic methods.