通过骨基质表面培养板检测RANKL诱导破骨细胞骨侵蚀能力

目的探讨以骨基质表面培养板替代骨磨片鉴定破骨细胞骨侵蚀能力的应用方法。方法通过RANKL诱导破骨前体细胞RAW264. 7建立破骨细胞分化模型,运用TRAP染色检测破骨细胞分化程度,并以骨基质表面培养板替代骨磨片行骨陷窝试验检测破骨细胞骨侵蚀能力,以侵蚀面积反映骨侵蚀能力。结果不同浓度的RANKL因子可有效诱导破骨前体细胞RAW264. 7分化为成熟多核破骨细胞,呈浓度依赖性。成熟破骨细胞在骨基质表面培养板上形成不同面积的不规则侵蚀圆环,趋势与破骨细胞分化程度一致。结论使用骨基质表面培养板可有效反映破骨细胞形成及骨侵蚀能力,与TRAP染色结果一致,并且具有操作简便、结果直观、便于统计分析等优点。

表面脱钙骨基质明胶修复大块骨缺损的实验与临床研究

目的 探讨表面脱钙骨基质明胶修复大块骨缺损的疗效及相关问题。方法 将 32只成年家兔随机分成A、B两组 ,双侧桡骨制成 1cm骨缺损 ,分别植入表面脱钙骨基质明胶 (SDBMG)、全脱钙骨基质明胶 (WDBMG)及SDBMG、自体骨 ,术后定期进行X线、组织学检查 (A组 )及生物力学测定 (B组 ) ;临床采用人SDBMG治疗大块骨缺损 31例 ,术后定期进行X线检查。结果 SDBMG呈由表及里的“渐进”诱导成骨过程 ;SDBMG的骨修复作用与自体骨相近 ,SDBMG侧抗压强度与自体骨侧的差异无显著性意义 ;临床随访示除 1例因适应症选择不当而失败外 ,其它 30例均治愈。结论 SDBMG具有良好的成骨作用和可靠的力学性能 ,可作为自体骨理想的替代材料修复大块骨缺损 ,但对活动期感染性骨缺损宜慎用。

微孔对同种异体表面脱钙骨基质明胶诱导成骨能力的影响

目的 观察微孔制备对表面脱钙骨基质明胶诱导成骨能力的影响。方法 用有微孔和无微孔表面脱钙骨基质明胶修复大鼠颅骨上直径为 8mm的环形骨缺损 ,术后不同时间行组织学和X线检查。结果 有微孔制备的表面脱钙骨基质明胶诱导成骨能力优于无微孔的表面脱钙骨基质明胶。结论 微孔制备能提高表面脱钙骨基质明胶诱导成骨的能力。

表面脱钙骨基质明胶诱导成骨修复颅骨大面积缺损的实验研究

目的:寻找替代自体骨移植修复颅骨大面积缺损的理想材料。方法:用表面脱钙骨基质明胶修复大鼠颅骨8 mm的圆形缺损,术后不同时间行x线、组织学检查。结果:表面脱钙骨基质明胶具有诱导成骨能力,保留骨的部分生物力学特性,但完全被新骨替代时间较长。结论:表面脱钙骨基质明胶是修复大面积颅骨缺损的理想材料。

表面脱钙骨基质明胶修复大块骨缺损的前瞻性临床研究

目的：探讨同种表面脱钙骨基质明胶(SDBMG)修复大块骨缺损的临床疗效及替代自体骨的可能性。方法：临床采用人表面脱钙骨基质明胶治疗大块骨缺损31例，术后定期进行X线检查，并观察伤口、体温、血常规及免疫球蛋白变化。结果：伤口一期愈合29例；因植入物直径过大、再次手术后伤口愈合1例；术后间断发热(<38．5℃)12例，1w后正常；除1例感染性骨缺损失败外，其他病例血常规及免疫球蛋白均正常，30例治愈。结论：SDBMG具有力学性能可靠、成骨作用及组织相溶性良好的特点，是长骨大块骨缺损的有效修复材料，可作为自体骨理想的替代材料用于临床，但对活动期感染性骨缺损宜慎用。

微孔同种异体表面脱钙骨基质明胶诱导成骨能力的实验研究

目的 :观察微孔制备对表面脱钙骨基质明胶诱导成骨能力的影响。方法 :用有微孔和无微孔表面脱钙骨基质明胶修复大鼠颅骨直径为 8mm的环形骨缺损 ,术后不同时间行组织学和X线检查。结果 :有微孔制备的表面脱钙骨基质明胶诱导成骨能力优于无微孔的表面脱钙骨基质明胶。结论

同种异体表面脱钙骨基质明胶诱导成骨能力的实验研究

目的 :观察表面脱钙骨基质明胶诱导成骨能力 ,寻找自体骨移植的理想替代材料。方法 :用表面脱钙骨基质明胶修复大鼠颅骨 8mm的圆形缺损 ,同自体骨、骨基质明胶移植对比 ,术后不同时间行X线、组织学检查。结果 :表面脱钙骨基质明胶同骨基质明胶诱导成骨能力相似 ,但完全被新骨替代时间较长。结论 :表面脱钙骨基质明胶是修复大面积或节段性骨缺损的理想材料。

自体外周血干细胞与骨基质明胶复合移植治疗骨缺损

目的观察自体外周血干细胞(autologous peripheral blood stem cells,APBSC)/表面脱钙骨基质明胶(bone matrix gelatin,BMG)共移植修复节段性骨缺损的疗效。方法 36例患者随机分为APBSC/BMG组(A组)及BMG组(B组)各18例,均行手术治疗,并行牢固内外固定。结果术后平均愈合时间A组为5个月,B组为8个月,两组间差异具有统计学意义(P<0.05);治疗期间患者未见明显不良反应。结论 APBSC/BMG复合移植较单纯BMG移植治疗骨缺损疗效好,无不良反应。

Cell surface activation of progelatinase A (proMMP-2) and cell migration

Gelatinase A (MMP-2) is considered to play a critical role in cell migration and invasion. The proteinase is secreted from the cell as an inactive zymogen. In vivo it is postulated that activation of progelationase A (proMMP-2) takes place on the cell surface mediated by membrane-type matrix metalloproteinases (MT-MMPs). Recent studies have demonstrated that proMMP-2 is recruited to the cell surface by interacting with tissue inhibitor of metalloproteinases-2 (TIMP-2) bound to MT1MMP by forming a ternary complex. bee MT1-MMP closely located to the ternary complex then activates proMMP-2 on the cell surface. MT1-MMP is found in cultured invasive cancer cells at the invadopodia. The MTMMP/TIMP-2/ MMP- 2 system t bus provides localized expression of proteolysis of the extracellular matrix required for cell migration.

The matrix metalloproteinase stromelysin-3 cleaves laminin receptor at two distinct sites between the transmembrane domain and laminin binding sequence within the extracellular domain

The matrix metalloproteinase (MMP) stromelysin-3 (ST3) has long been implicated to play an important role in extracellular matrix (ECM) remodeling and cell fate determination during normal and pathological processes. However like other MMPs, the molecular basis of ST3 function in vivo remains unclear due to the lack of information on its physiological substrates. Furthermore, ST3 has only weak activities toward all tested ECM proteins. Using thyroid hormone-dependent Xenopus laevis metamorphosis as a model, we demonstrated previously that ST3 is important for apoptosis and tissue morphogenesis during intestinal remodeling. Here, we used yeast two-hybrid screen with mRNAs from metamorphosing tadpoles to identify potential substrate of ST3 during development. We thus isolated the 37 kd laminin receptor precursor (LR). We showed that LR binds to ST3 in vitro and can be cleaved by ST3 at two sites distinct from where other MMPs cleave. Through peptide sequencing, we determined that the two cleavage sites are in the extracellular domain between the transmembrane domain and laminin binding sequence. Furthermore, we demon strated that these cleavage sites are conserved in human LR. These results together with high levels of human LR and ST3 expression in carcinomas suggest that LR is a likely in vivo substrate of ST3 and that its cleavage by ST3 may alter cell-extracellular matrix interaction, thus, playing a role in mediating the effects of ST3 on cell fate and behavior ob- served during development and pathogenesis.

Surface plasmon resonance analysis to evaluate the importance of heparin sulfate groups＇ binding with human aFGF and bFGF

Human acidic and basic fibroblast growth factors (aFGF and bFGF) are classic and well characterized members of the heparin binding growth factor family. Heparin is generally thought to play an extremely important role in regulating aFGF and bFGF bioactivities through its strong binding with them. In order to unravel the mechanism of the interactions between heparin and FGFs, and evaluate the importance of heparin sulfate groups' binding with FGFs, surface plasmon resonance analyses were performed using IAsys Cuvettes System. Heparin and its regioselectively desulfated derivatives were immobilized on the cuvettes. aFGF and bFGF solutions with different concentrations were pipetted into the cuvettes and the progress of the interaction was monitored in real\|time by Windows based software, yielding kinetic and equilibrium constants for these interactions. In addition, in order to reduce the delicate difference among the cuvettes, inhibition analyses of mixture of FGFs and immobilized native heparin by modified heparins were also done. The data from these two methods were similar, indicating that all sulfate groups at 2 O, 6 O and N in heparin were required for the binding to aFGF; and that their contribution to the binding was in the order 2 O, N and 6 O sulfate group. In contrast, definite contribution of the 6 O sulfate group to the binding with bFGF was most apparent, while the other two sulfate groups appeared to be necessary in the order 2 O and N sulfate group. These methods established here can be used for analysing the effect of sulfate groups in heparin on the binding with other human FGF members or other heparin binding proteins.

Influence of nitrogen hetero-substitution on the electrochemical performance of coal-based activated carbons measured in non-aqueous electrolyte

Nitrogen-containing carbons were prepared by modification of activated carbons.The modified carbons were used as electrode materials with improved electrochemical performance.Precursor anthracite was activated by KOH(KOH:anthracite= 1:1), modified by melamine or urea and then treated at 1173 K to obtain the modified carbons.The porous structure, the chemical composition and the electrochemical characteristics of the carbons were investigated by nitrogen sorption, XPS and electrochemical methods respectively.Electrochemical experiments were performed in an organic electrolytic solution of 1 M(C2H5)4NBF4/PC.The samples modified by the different methods showed differences in chemical composition that introduced varying degrees of electrochemical performance enhancement.The presence of nitrogen enhanced the electron donor properties and the surface wettability of the activated carbons:this ensured a sufficient utilization of the exposed surface for charge storage.

Genetic Function Approximation Based QSPR Models for Predicting the Wetting Ability of Lubricants onto Rolled Copper Foil Surface

The contact angle phenomena and wetting behavior of fatty acids,alcohols and ester used as additives in lubricants onto the rolled copper foil(RCF)surface were studied by the static sessile drop method.Semi-empirical quantum-chemical method studies on the contact angle of these compounds onto surface using several structural parameters were carried out.Molecular refractivity as well as several structural parameters were adopted in the development of quantitative structure-property relationships(QSPR)using genetic function approximation(GFA)statistical analysis method.The results show that quantum parameters are a better choice when predicting the contact angle and wettability of lubricants onto the RCF surface.Contact angle of the compounds serves as a function of their viscosity,interfacial tension,and physicochemical parameters.Alog P,molecular refractivity,molecular flexibility,total molecular mass,solvent surface area,element count,total energy and dipole are the most sensitive ones among the major contributing parameters.Notably,studies of lubricants on the RCF surfaces allow wetting theories to be tested down to the microcosmic scale,which can bring about new insight to predict wettability of lubricants onto RCF surface.

EFFECT OF SURFACTANT SDS ON DETERMINATION OF NUCLEIC ACID WITH TERBIUM (III) FLUORESENCE

The effect of an anionic surfactant (sodium dodecyl sulfate, SDS) on the fluorescence properties of nucleic acid with terbium (III) is studied. Results show that ribonucleic acid (RNA) presents fluorescence reaction with Tb (III) directly, but deoxyribonucleic acid (DNA) presents similar fluorescence reaction only after its denaturation. In the presence of SDS, the fluorescence intensity is 4.0 times and 3.5 times greater than that of DNA and RNA without SDS.

Study of Wetting Properties of Carbon Nanofiber Coatings on Various Substrates

The role of roughness and composition on the wetting characteristics of a series of carbon nanofiber based coatings were studied in order to evaluate its superhydrophobic properties. In this study, idealized surfaces were created from a smooth stainless steel and aluminium sheets and two other stainless steel sheets with different textured surfaces. All surfaces were coated with carbon nanofiber alcohol solutions in order to generate coatings of variable compositions using mixtures of isopropanol, water and a commercial carbon nanofibre. The optimum concentration of carbon nanofiber in coatings was obtained to produce superhydrophobic surfaces. A general trend of increasing hydrophobicity was observed for coated surfaces as compared to the bare substrate. Individual contact angles were dependent on the nature of the underlying substrate, relative surface pattern, and roughness. Overall wetting properties were dependent upon composition and micro scale roughness of the coatings.

Effects of surface chemical properties of activated coke on selective catalytic reduction of NO with NH_3 over commercial coal-based activated coke

Surface chemical properties of typical commercial coal-based activated cokes were characterized by Xray photoelectron spectroscopy(XPS) and acid-base titration, and then the influence of surface chemical properties on catalytic performance of activated cokes of NO reduction with NH3 was investigated in a fixed-bed quartz micro reactor at 150 ℃. The results indicate that the selective catalytic reduction(SCR) activity of activated cokes with the increase of its surface acidic sites and oxygen content,obviously, a correlation between catalytic activity and surface acidic sites content by titration has higher linearity than catalytic activity and surface oxygen content by XPS. While basic sites content by acid-base titration have not correlation with SCR activity. It has been proposed that surface basic sites content measured by titration may not be on adjacent of acidic surface oxides and then cannot form of NO2-like species, thus the reaction of reduction of NO with NH3 have been retarded.

Influence of Surface Geometry of Grating Substrate on Director in Nematic Liquid Crystal Cell

The director in nematic liquid crystal cell with a weak anchoring grating substrate and a strong anchoring planar substrate is relative to the coordinates x and z.The influence of the surface geometry of the grating substrate in the cell on the director profile is numerically simulated using the two-dimensional finite-difference iterative method under the condition of one elastic constant approximation and zero driven voltage.The deepness of groove and the cell gap affect the distribution of director.For the relatively shallow groove and the relatively thick cell gap,the director is only dependent on the coordinate z.For the relatively deep groove and the relatively thin cell gap,the director must be dependent on the two coordinates x and z because of the increased elastic strain energy induced by the grating surface.

Influence of the Surface and Structural Characteristics of Activated Carbons on Adsorptive Removal of Halo-Olefinic Impurities from 1,1,1,3,3-Pentafluoropropane

Halo-olefinic impurities in 1,1,1,3,3-pentafluoropropane （HFC-245fa） product used as blowing agents, etc. could damage the human body and must be removed. Activated carbon was treated by HCI, HN03 and NaOH, respectively. The adsorptive performance of unmodified and modified activated carbons for the removal of a low con- tent of l-chloro-3,3,3-trifluoro-l-propene （HCFC-1233zd）, 1,3,3,3-tetrafluoro-l-propene （HFC-1234ze）, 1- chloro-l,3,3,3-tetrafluoro-l-propene （HFC-1224zb） and 2-chloro-l,3,3,3-tetrafluoro-l-propene （HFC-1224xe） halo-olefins in the 1,1,1,3,3-pentafluoropropane （HFC-245fa] product was investigated. These halo-olefinic im- purities could be substantially removed from the HFC-245fa product via the adsorption over activated carbon when the adsorption temperature was under 333 K, which can be attributed to the n-n dispersion interactions between the halo-olefins and carbon graphite layer. The basic surface groups of activated carbon could catalyze the decomposition of HFC-245fa to form HFC-1234ze. However, the significant increase in the amount of surface acidic groups of activated carbon led to a distinct decrease of adsorption capacity due to the reduction in the mi- cropore volume of adsorbent and a decrease in the strength of the n-n dispersive interactions between halo- olefin molecules and carbon basal. The breakthrough time of halo-olefinic impurities on activated carbon in- creased with the increase of molecular mass and the decrease of molecular symmetry.

Interface and Surface Properties of Nano-hydroxyapatite /Poly (1,4-PhenyleneSulfide)-Poly(2,4-Phenylene Sulfide Acid) Copolymer Composite

The interface and surface properties of nano-hydroxyapatite(n-HA) and poly( 1, 4-phenylene sulfide)-poly (2,4-phenylene sulfide acid)(PPS-PPSA) copolymer composite were investigated. The results show that there are some strong interface combinations of calcium ion (Ca2+ ), car-boxyl (-COO- ) and phosphate radicle ion (PO_4~3- ) between copolymer and n-HA in the composite. The presence of the 2,4-phenylene sulfide acid in copolymer can increase the affinity to n-HA, which causes the formation of chemical bindings between the PPS-PPSA copolymer and n-HA. XRD analysis and IR surface analysis indicate that n-HA is not encapsulated by copolymer but exposed on the surface of the composite, and has same structure and properties with the origi-nal n-HA. The presence of the interface chemical bindings between the PPS-PPSA copolymer and n-HA can increase the content of n-HA in composite but does not cause the decrease of the composite mechanical strength.