Carbon Fiber Breakage Mechanism in Aluminum(Al)/Carbon Fibers(CFs) Composite Sheet during Accumulative Roll Bonding(ARB) Process

We put forward a method of fabricating Aluminum(Al)/carbon fibers(CFs) composite sheets by the accumulative roll bonding(ARB) method. The finished Al/CFs composite sheet has CFs and pure Al sheets as sandwich and surface layers. After cross-section observation of the Al/CFs composite sheet, we found that the CFs discretely distributed within the sandwich layer. Besides, the tensile test showed that the contribution of the sandwich CFs layer to tensile strength was less than 11% compared with annealed pure Al sheet. With ex-situ observation of the CFs breakage evolution with-16%,-32%, and-45% rolling reduction during the ARB process, the plastic instability of the Al layer was found to bring shear damages to the CFs. At last, the bridging strengthening mechanism introduced by CFs was sacrificed. We provide new insight into and instruction on Al/CFs composite sheet preparation method and processing parameters.

Estimation of cancer cell migration in biomimetic random/oriented collagen fiber microenvironments

Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment,playing a crucial role in pathological processes such as tumor invasion and metastasis.However,conventional two-dimensional cell culture and animal models have limitations in studying the influence of tumor microenvironment on cancer cell migration.Fortunately,the further development of microfluidic technology has provided solutions for the study of such questions.We utilize microfluidic chip to build a random collagen fiber microenvironment(RFM)model and an oriented collagen fiber microenvironment(OFM)model that resemble early stage and late stage breast cancer microenvironments,respectively.By combining cell culture,biochemical concentration gradient construction,and microscopic imaging techniques,we investigate the impact of different collagen fiber biochemical microenvironments on the migration of breast cancer MDA-MB-231-RFP cells.The results show that MDA-MB-231-RFP cells migrate further in the OFM model compared to the RFM model,with significant differences observed.Furthermore,we establish concentration gradients of the anticancer drug paclitaxel in both the RFM and OFM models and find that paclitaxel significantly inhibits the migration of MDA-MB-231-RFP cells in the RFM model,with stronger inhibition on the high concentration side compared to the low concentration side.However,the inhibitory effect of paclitaxel on the migration of MDA-MB-231-RFP cells in the OFM model is weak.These findings suggest that the oriented collagen fiber microenvironment resembling the late-stage tumor microenvironment is more favorable for cancer cell migration and that the effectiveness of anticancer drugs is diminished.The RFM and OFM models constructed in this study not only provide a platform for studying the mechanism of cancer development,but also serve as a tool for the initial measurement of drug screening.

Anti-abrasion collagen fiber-based membrane functionalized by UiO-66-NH_(2)with ultra-high efficiency and stability for oil-in-water emulsions separation

Membrane separation strategies offer promising platform for the emulsion separation.However,the low mechanical strength of membrane separation layers and the trade-off between separation flux and efficiency present significant challenges.In this study,we report a CFM@UiO-66-NH_(2)membrane with high separation flux,efficiency and stability,through utilizing a robust anti-abrasion collagen fiber membrane(CFM)as the multifunctional support and UiO-66-NH_(2)by an in-situ growth as the separation layer.The high mechanical strength of the CFM compensated for the weakness of the separation layer,while the charge-breaking effect of UiO-66-NH_(2),along with the size sieving of its constituent separating layers and the capillary effect of the collagen fibers,contributed to the potential for efficient separation.Additionally,the CFM@UiO-66-NH_(2)membrane exhibited superhydrophilic properties,making it suitable for separating oil-in-water microemulsions and nanoemulsions stabilized by anionic surfactants.The membrane demonstrated remarkable separation efficiencies of up to 99.960%and a separation flux of370.05 L·m^(-2)·h^(-1).Moreover,it exhibits stability,durability,and abrasion resistance,maintaining excellent separation performance even when exposed to strong acids and alkalis without any damage to its structure and performance.After six cycles of reuse,it achieved a separation flux of 417.97 L·m^(-2)·h^(-1)and a separation efficiency of 99.747%.Furthermore,after undergoing 500 cycles of strong abrasion,the separation flux remained at 124.39 L·m^(-2)·h^(-1),with a separation efficiency of 99.992%.These properties make it suitable for the long-term use in harsh operating environments.We attribute these properties to the electrostatic effect resulting from the amino group on UiO-66-NH_(2)and its in-situ growth on the CFM,which forms a size-screening separation layer.Our work highlights the potential of the CFM@UiO-66-NH_(2)membrane as an environmentally friendly size-screening material for the efficient emulsion wastewater separation.

Three-dimensional remodeling of collagen fibers within cervical tissues in pregnancy

The cervix is a collagen-rich connective tissue that must remain closed during pregnancy while undergoing progressive remodeling in preparation for delivery,which begins before the onset of the preterm labor process.Therefore,it is important to resolve the changes of collagen flbers during cervical remodeling for the prevention of preterm labor.Herein,we assessed the spatial organization of collagen flbers in a three-dimensional(3D)context within cervical tissues of mice on day 3,9,12,15 and 18 of gestation.We found that the 3D directional variance,a novel metric of alignment,was higher on day 9 than that on day 3 and then gradually decreased from day 9 to day 18.Compared with two-dimensional(2D)approach,a higher sensitivity was achieved from 3D analysis,highlighting the importance of truly 3D quantification.Moreover,the depthdependent variation of 3D directional variance was investigated.By combining multiple 3D directional variance-derived metrics,a high level of classification accuracy was acquired in distinguishing different periods of pregnancy.These results demonstrate that 3D directional variance is sensitive to remodeling of collagen fibers within cervical tissues,shedding new light on highly-sensitive,early detection of preterm birth(PTB).

Dietary protein levels changed the hardness of muscle by acting on muscle fiber growth and the metabolism of collagen in sub-adult grass carp(Ctenopharyngodon idella)

Background:Nutrient regulation has been proven to be an effective way to improve the flesh quality in fish.As a necessary nutrient for fish growth,protein accounts for the highest proportion in the fish diet and is expensive.Although our team found that the effect of protein on the muscle hardness of grass carp was probably related to an increased collagen content,the mechanism for this effect has not been deeply explored.Moreover,few studies have explored the protein requirements of sub-adult grass crap(Ctenopharyngodon idella).Therefore,the effects of different dietary protein levels on the growth performance,nutritional value,muscle hardness,muscle fiber growth,collagen metabolism and related molecule expression in grass carp were investigated.Methods:A total of 450 healthy grass carp(721.16±1.98 g)were selected and assigned randomly to six experimen-tal groups with three replicates each(n=25/replicate),and were fed six diets with 15.91%,19.39%,22.10%,25.59%,28.53%and 31.42%protein for 60 d.Results:Appropriate levels of dietary protein increased the feed intake,percentage weight gain,specific growth rate,body composition,unsaturated fatty acid content in muscle,partial free amino acid content in muscle,and muscle hardness of grass carp.These protein levels also increased the muscle fiber density,the frequency of new muscle fibers,the contents of collagen and IGF-1,and the enzyme activities of prolyl 4-hydroxylases and lysyloxidase,and decreased the activity of matrix metalloproteinase-2.At the molecular level,the optimal dietary protein increased col-lagen type Iα1(Colα1),Colα2,PI3K,Akt,S6K1,La ribonucleoprotein domain family member 6a(LARP6a),TGF-β1,Smad2,Smad4,Smad3,tissue inhibitor of metalloproteinase-2,MyoD,Myf5,MyoG and MyHC relative mRNA levels.The levels of the myostatin-1 and myostatin-2 genes were downregulated,and the protein expression levels of p-Smad2,Smad2,Smad4,p-Akt,Akt,LARP6 and Smad3 were increased.Conclusions:The appropriate levels of dietary protein promoted the growth of sub-adult grass carp and improved muscle hardness by promoting the growth of muscle fibers,improving collagen synthesis and depressing collagen degradation.In addition,the dietary protein requirements of sub-adult grass carp were 26.21%and 24.85%according to the quadratic regression analysis of growth performance(SGR)and the muscle hardness(collagen content),respectively.

自成核行为在CF/PPS复合材料中的差异性与普适性

以半结晶高分子为基体的碳纤维增强热塑性复合材料,其基体的结晶行为将受到碳纤维表面性质与热历史的共同影响。当这种材料在经历反复加热冷却的热循环过程时,基体会产生自成核行为,其结晶过程变得更加复杂。通过三种T300级碳纤维分别制备了碳纤维增强聚苯硫醚(CF/PPS)复合材料,并探究了二次熔融温度与CF/PPS复合材料结晶行为的关系,揭示了不同碳纤维表面性质对CF/PPS复合材料自成核行为的影响。在此基础上阐明了CF/PPS复合材料基体自成核与CF异相成核的竞争关系。最后,通过冲压成型制得具有自成核行为的CF/PPS复合材料角片,验证了自成核对于CF/PPS复合材料二次热成型技术的有效性与重要性。

碳纤维/聚醚醚酮(CF/PEEK)复合材料摩擦磨损性能及抗摩擦静电特性研究

利用真空热压烧结技术制备了不同碳纤含量的碳纤维/聚醚醚酮(CF/PEEK)复合材料,采用热导率分析仪和热重测试仪对材料的热学性能进行表征,并利用多功能摩擦磨损试验机、三维形貌轮廓仪、扫描电子显微镜和摩擦静电计对材料的摩擦磨损性能和抗摩擦静电性能进行分析。分析结果表明:随着CF添加量的增加,复合材料摩擦因数、磨损率和摩擦静电电压先降低后升高,当CF添加量(质量分数)为20%时,摩擦因数、磨损率和摩擦静电电压达到最低,分别为0.247、5.6×10^(-6)mm/(N·m)和3.3 V,证明此种方法制备的20%CF/PEEK材料具有优异的摩擦磨损性能和抗静电性能。CF/PEEK复合材料磨损机理以黏着磨损为主,并且伴随着轻微的磨粒磨损。

Remodeling of skin nerve fibers during burn wound healing

Burn wound healing involves a complex sequence of processes. Recent studies have revealed that skin reinnervation may have an impact on physiological wound repair. Few studies have addressed the process of reinnervation and morphological changes in regenerated nerve fibers. The regeneration of neurites during full-thickness burn wound healing was determined by immunofluorescent staining using an anti-neurofilament protein monoclonal antibody, and three-dimensional morphology was observed under a laser scanning confocal microscope. Morphology and the volume fraction of collagen and nerve fibers were measured. Skin reinnervation increased during wound healing, peaked during the proliferative scar stage, and then decreased to lower levels during the maturation period. The results from the skin nerve fibers correlated with those from collagen using semi-quantitative analysis. Disintegration and fragmentation were observed frequently in samples from the proliferative stage, and seldom occurred during the maturation stage. There was a remodeling process of regenerated nerve fibers during wound healing, which comprised changed innervation density and topical morphology. The mechanism of remodeling for nerve fibers requires further investigation.

Adsorptive Recovery of Uranium from Nuclear Fuel Industrial Wastewater by Titanium Loaded Collagen Fiber

Effective recovery of UO2+2 from wastewater is essential for nuclear fuel industry and related industries.In this study,a novel adsorbent was prepared by loading titanium(Ti4+) onto collagen fiber(TICF),and its physical and chemical properties as well as adsorption to UO2+2 in nuclear fuel industrial wastewater were investigated.It is found that TICF can effectively recover UO2+2 from the wastewater with excellent adsorption capacity.The adsorption capacity is 0.62 mmol·g-1 at 303 K and pH 5.0 when the initial concentration of UO2+2 is 1.50 mmol·L-1.The adsorption isotherms can be described by the Langmuir equation and the adsorption capacity increases with temperature.The effect of co-existed F on the adsorption capacity for UO2+2 is significant,which can be eliminated by adding aluminum ions as complexing agent,while the other co-existed ions in the solutions,including HCO-3,Cl-,NO-3,Ca2+,Mg2+ and Cu2+,have little effect on the adsorption capacity for UO2+2.The saturated TICF after UO2+2 adsorption can be regenerated by using 0.2 mol·L-1 nitrate(HNO-3) as desorption agent,and the TICF can be reused at least three times.Thus the TICF is a new and effective adsorbent for the recovery of UO2+2 from the wastewater.

Evaluation of diffusion in gel entrapment cell culture within hollow fibers

AIM: To investigate diffusion in mammalian cell culture by gel entrapment within hollow fibers. METHODS: Freshly isolated rat hepatocytes or human oral epidermoid carcinoma (KB) cells were entrapped in type I collagen solutions and statically cultured inside microporous and ultrafiltration hollow fibers. During the culture time collagen gel contraction, cell viability and specific function were assessed. Effective diffusion coefficients of glucose in cell-matrix gels were determined by lag time analysis in a diffusion cell. RESULTS: Significant gel contractions occurred in the collagen gels by entrapment of either viable hepatocytes or KB cells. And the gel contraction caused a significant reduction on effective diffusion coefficient of glucose. The cell viability assay of both hepatocytes and KB cells statically cultured in hollow fibers by collagen entrapment further confirmed the existence of the inhibited mass transfer by diffusion. Urea was secreted about 50% more by hepatocytes entrapped in hollow fibers with pore size of 0.1 μm than that in hollow fibers with MWCO of 100 ku. CONCLUSION: Cell-matrix gel and membrane pore size are the two factors relevant to the limited mass transfer by diffusion in such gel entrapment of mammalian cell culture.

Electroless nickel plating on the surface of carbon fibers

The electroless nickel plating on the surface of carbon fibers was prepared by pretreating the carbon fibers in order to increase their conductivity,and consequently enhance the EMI shielding effectiveness of the composites.The relationship between the performance of depositing coat and pH value,temperature,reaction time and the way of agitation was studied.Results show that the depositing quality is stable under pH between 4.5 and 5.0,temperature between 75 ℃ and 85 ℃,reaction time for 10 min and air agitation.The uniform and compact nickel layer deposited on carbon fibers was proved by XRD and SEM,and the electrical resistivity of carbon fibers with nickel coating was tested.Results indicate that the electrical resistivity of carbon fibers with electroless nickel plating is decreased by an order of magnitude compared with that of carbon fibers.It means that nickel coating can greatly improve the electromagnetic interference shielding properties of carbon fibers.

A method of removing retardance induced by scattering of collagenous fiber bundles

In this work,we report a method of removing scattering induced retardance in polarization sensitive fnll field optical coherence tomography(PS-FFOCT).First,the Mueller matrix that describes its operation is derived.The thickness invariant retardance induced by the scattering of collagenous fiber bundles is then used to find the accurate values of the birefringence of the layers that consist collagenous fibers.Finally,the initial en face birefringent images of in vitro beef tendon samples are presented to demonstrate the capability of our method.

APPLICATION OF THE COLLAGENOUS FIBER FROM THE SOLID WASTES OF LEATHER FOR PAPERMAKING

The capability of pulping for the solid waste of leather was investigated. The properties of paper that made up of collagenous fiber and plant fiber were also analyzed. The result showed that by proper treatment, solid waste of leather could be made into collagen fiber for papermaking. The physical strength of paper can be enhanced by appending collagenous fiber in a proper propriety.

Characterization of Amino Terminated Hyperbranched Collagen Fiber and Adsorption Thermodynamics to Cr(Ⅵ)

In this study, a novel adsorption material amino terminated hyperbranched polyamide collagen fiber( CF-HBPN)was prepared by loading amino terminated hyperbranched polyamide( HBPN) which was synthesized by polycondensation of methacrylate and diethylenetriamine onto the surface of collagen fiber( CF) with glutaraldehyde as the cross-linking agent. X-ray photoelectron spectroscopy( XPS) and thermogravimetric analysis( TGA) were employed to characterize the structures of CF and CFHBPN. In addition,the adsorption property of CF-HBPN toward Cr( Ⅵ) and adsorption thermodynamic were studied as well. The experimental results indicated that the Cr( Ⅵ) 's removal rate by CF-HBPN was 3. 09 higher than that of CF under the same conditions. Langmuir single layer adsorption model was found more suitable to describe the adsorption process than Freundlich adsorption model. The adsorption process was an endothermic reaction. The adsorption efficiency was enhanced with the increase of temperature. X-ray diffraction( XRD) was employed to elucidate the difference between CF-HBPN and Cr( Ⅵ) loaded CF-HBPN[CF-HBPN-Cr( Ⅵ) ].

A 3D biophysical model for cancer spheroid cell-enhanced invasion in collagen-oriented fiber microenvironment

The process of in situ tumors developing into malignant tumors and exhibiting invasive behavior is extremely complicated.From a biophysical point of view,it is a phase change process affected by many factors,including cell-to-cell,cell-to-chemical material,cell-to-environment interaction,etc.In this study,we constructed spheroids based on green fluorescence metastatic breast cancer cells MDA-MB-231 to simulate malignant tumors in vitro,while constructed a three-dimensional(3D)biochip to simulate a micro-environment for the growth and invasion of spheroids.In the experiment,the 3D spheroid was implanted into the chip,and the oriented collagen fibers controlled by collagen concentration and injection rate could guide the MDA-MB-231 cells in the spheroid to undergo directional invasion.The experiment showed that the oriented fibers greatly accelerated the invasion speed of MDA-MB-231 cells compared with the traditional uniform tumor micro-environment,namely obvious invasive branches appeared on the spheroids within 24 hours.In order to analyze this interesting phenomenon,we have developed a quantitative analyzing approach to explore strong angle correlation between the orientation of collagen fibers and invasive direction of cancer cell.The results showed that the oriented collagen fibers produced by the chip can greatly stimulate the invasion potential of cancer cells.This biochip is not only conducive to modeling cancer cell metastasis and studying cell invasion mechanisms,but also has the potential to build a quantitative evaluation platform that can be used in future chemical drug treatments.

CF/Fe_(3)O_(4)增强环氧树脂吸波复合材料的性能研究

为了弥补吸波复合材料在应用上的局限性,采用原位还原法制备负载Fe_(3)O_(4)颗粒的碳纤维(CF/Fe_(3)O_(4)),通过浇铸成型将CF/Fe_(3)O_(4)复合纤维与环氧树脂进行复合,制备了CF/Fe_(3)O_(4)增强环氧树脂吸波复合材料。研究了CF/Fe_(3)O_(4)复合纤维长度、添加量、复合材料厚度对复合材料吸波性能和弯曲强度的影响。研究发现:当CF/Fe_(3)O_(4)复合纤维长度为4 mm、添加量为0.8%、复合材料厚度为4.5 mm时,CF/Fe_(3)O_(4)增强环氧树脂吸波复合材料的吸波效果最优,最大反射损耗在18 GHz处达-16.8 dB,有效带宽为3.8 GHz,较同制备工艺条件下的CF增强环氧树脂复合材料的反射损耗(-4.75 dB)提升了253.7%。

CF/ASA复合材料的电磁屏蔽性能影响因素

通过填料分散复合法制备CF/ASA(苯乙烯、丙烯晴和丙烯酸酯类橡胶体的接枝共聚物)复合材料,研究CF的长度及含量对复合材料电磁屏蔽效能的影响,并且,对其导电性和微观形貌进行表征。激光共聚焦显微镜研究结果显示,复合材料内部碳纤维分散均匀,碳纤维之间相互搭接形成了较好的导电网络。分析表明,随着导电性的提升,复合材料电磁屏蔽性能逐渐提升;随着纤维含量的增加,复合材料的膜电阻逐渐减小,其电磁屏蔽效能得到提高,当碳纤维含量为29%、碳纤维长度为6 mm的复合材料样品膜电阻最小,其值为23.36Ω/sq,而有效屏蔽带宽达到最大,其值为6 GHz,电磁屏蔽性能最优。电磁波频率在10~15 GHz范围内,复合材料具有较好的电磁屏蔽性能,并且,碳纤维长度越长,复合材料电磁屏蔽效能越好。

Electrospinning and Electrospun Nanofibers

Electro-spinning is a very modern process which can be used in various purposes. We did this experimental work at Swerea IVF in Sweden during M. Sc in Textile Technology programme at University of Bor?s. We should especially thank our supervisor—Anna Thorvaldsson and course teacher—Ioannis S. Chronakis. In this report, we have tried to explain the basic manufacturing techniques of the electrospun nanofiber by the electro-spinning, how one can characterize it by SEM (Scanning Electron Microscopy) and its various applications in the practical field, e.g wound healing, Tissue Engineering Scaffold. The experimental work helped us a lot to gather sufficient knowledge about the electro-spinning process which we wanted to share with all.

Rapid and efficient characterization of cervical collagen orientation using linearly polarized colposcopic images

Collagen provides tissue strength and structural integrity.Quanti fication of the orientated dispersion of collagen fibers is an important factor when studying the mechanical properties of the cervix.In this study,for the first time,a new method for rapid characterization of the collagen fiber orientations of the cervix using linearly polarized light colposcopy is presented.A total of 24 colposcopic images were captured using a cross-polarized imaging system with white LED light sources.In the preprocessing stage,the Red channel of the RGB image was chosen,which contains no information of the blood vessels because of the low-absorption of blood cells in the red region.OrientationJ,which is an ImageJ plug-in,was used to estimate the local orientation of the collagen fibers.The result shows that in the nonpregnant cervix,the middle zone(Zone 2)has circumferentially aligned collagen fibers while the inner zone(Zone 1)has randomly arranged.The collagen fiber dispersion in Zone 2 is much smaller than that in Zone 1 at all four quadrants region(anterior,posterior,left,and right quadrant).This new analysis technique could potentially combine with diagnostic tools to provide a quantitative platform of collagen fibers in the clinic.

国产三维五向M55JCf/Al复合材料的显微组织和弯曲性能

研究国产三维五向M55JCf/Al复合材料的显微组织和致密度以及在室温和350℃下的弯曲性能。结果表明:国产三维五向M55JCf/Al复合材料的致密度为98%,显微组织无明显缺陷,仅存在少量的纤维团聚现象和浸渗微孔缺陷;在室温和350℃的弯曲强度分别为505 MPa和335 MPa,弯曲模量分别为158 GPa和138 GPa,表现出优良的室温、高温弯曲性能。