3D printing of silk fibroin-based hybrid scaffold treated with platelet rich plasma for bone tissue engineering

3D printing/bioprinting are promising techniques to fabricate scaffolds with well controlled and patient-specific structures and architectures for bone tissue engineering. In this study, we developed a composite bioink consisting of silk fibroin (SF), gelatin (GEL), hyaluronic acid (HA), and tricalcium phosphate (TCP) and 3D bioprinted the silk fibroin-based hybrid scaffolds. The 3D bioprinted scaffolds with dual crosslinking were further treated with human platelet-rich plasma (PRP) to generate PRP coated scaffolds. Live/Dead and MTT assays demonstrated that PRP treatment could obviously promote the cell growth and proliferation of human adipose derived mesenchymal stem cells (HADMSC). In addition, the treatment of PRP did not significantly affect alkaline phosphatase (ALP) activity and expression, but significantly upregulated the gene expression levels of late osteogenic markers. This study demonstrated that the 3D printing of silk fibroin-based hybrid scaffolds, in combination with PRP post-treatment, might be a more efficient strategy to promote osteogenic differentiation of adult stem cells and has significant potential to be used for bone tissue engineering

Analysis of DNA Methylation in Various Swine Tissues

DNA methylation is known to play an important role in regulating gene expression during biological development and tissue differentiation in eukaryotes. In this study, we used the fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) method to assess the extent and pattern of cytosine methylation in muscle, heart, liver, spleen, lung, kidney and stomach from the swine strain Laiwu, and we also examined specific methylation patterns in the seven tissues. In total, 96,371 fragments, each representing a recognition site cleaved by either or both EcoRI + HpaII and EcoRI + MspI, the HpaII and MspI are isoschizomeric enzymes, were amplified using 16 pairs of selective primers. A total of 50,094 sites were found to be methylated at cytosines in seven tissues. The incidence of DNA methylation was approximately 53.99% in muscle, 51.24% in the heart, 50.18% in the liver, 53.31% in the spleen, 51.97% in the lung, 51.15% in the kidney and 53.39% in the stomach, as revealed by the incidence of differential digestion. Additionally, differences in DNA methylation levels imply that such variations may be related to specific gene expression during tissue differentiation, growth and development. Three types of bands were generated in the F-MSAP profile, the total numbers of these three types of bands in the seven tissues were 46,277, 24,801 and 25,293, respectively

3D printing of silk fibroin-based hybrid scaffold treated with platelet rich plasma for bone tissue engineering

3D printing/bioprinting are promising techniques to fabricate scaffolds with well controlled and patient-specific structures and architectures for bone tissue engineering. In this study, we developed a composite bioink consisting of silk fibroin (SF), gelatin (GEL), hyaluronic acid (HA), and tricalcium phosphate (TCP) and 3D bioprinted the silk fibroin-based hybrid scaffolds. The 3D bioprinted scaffolds with dual crosslinking were further treated with human platelet-rich plasma (PRP) to generate PRP coated scaffolds. Live/Dead and MTT assays demonstrated that PRP treatment could obviously promote the cell growth and proliferation of human adipose derived mesenchymal stem cells (HADMSC). In addition, the treatment of PRP did not significantly affect alkaline phosphatase (ALP) activity and expression, but significantly upregulated the gene expression levels of late osteogenic markers. This study demonstrated that the 3D printing of silk fibroin-based hybrid scaffolds, in combination with PRP post-treatment, might be a more efficient strategy to promote osteogenic differentiation of adult stem cells and has significant potential to be used for bone tissue engineering

Effect of structure on dynamical stab-resistance behaviors of laminates composite

The dynamic stab-resistance behaviors of laminate composites composed of TA15, TA1 titanium with various thicknesses of ultra-high-molecular-weight polyethylene, and polyester fabrics are characterized under dynamic stab testing conditions and analyzed by a new method using the average velocity of tension-compaction-plastic deformation process to calculate the ratio of energy in different damage process. The damaged area is observed by optical microscopy and SEM, and the impact force-time curve and damage degree are analyzed, and the energy of different processes during the dynamic stab test is calculated. The results show that laminates with the structure of high strength material among the low strength materials have much better performance than other specimens

3D printing of silk fibroin-based hybrid scaffold treated with platelet rich plasma for bone tissue engineering

3D printing/bioprinting are promising techniques to fabricate scaffolds with well controlled and patient-specific structures and architectures for bone tissue engineering. In this study, we developed a composite bioink consisting of silk fibroin (SF), gelatin (GEL), hyaluronic acid (HA), and tricalcium phosphate (TCP) and 3D bioprinted the silk fibroin-based hybrid scaffolds. The 3D bioprinted scaffolds with dual crosslinking were further treated with human platelet-rich plasma (PRP) to generate PRP coated scaffolds. Live/Dead and MTT assays demonstrated that PRP treatment could obviously promote the cell growth and proliferation of human adipose derived mesenchymal stem cells (HADMSC). In addition, the treatment of PRP did not significantly affect alkaline phosphatase (ALP) activity and expression, but significantly upregulated the gene expression levels of late osteogenic markers. This study demonstrated that the 3D printing of silk fibroin-based hybrid scaffolds, in combination with PRP post-treatment, might be a more efficient strategy to promote osteogenic differentiation of adult stem cells and has significant potential to be used for bone tissue engineering

Preparation of boron nitride fiber by organic precursor method

In this paper, boron nitride polymer precursor was made by boric acid, melamine, twelve sodium alkyl sulfate as raw materials and pure water as medium which is heated to 70 °C. Boron nitride precursor polymer was soluble in formic acid solution. The boron nitride precursor can be electrostatically spun at the voltage in 23 kV and the distance between the positive and negative poles is 15 cm. The formed fiber is very uniform. The properties of the precursors were analyzed through electron microscope, infrared spectrum, X-ray and ultraviolet spectrum. The aim of the job is to got the precursor of BN and spun it. Keywords: Melamine, Boric acid, Boron nitride precursor, Electrostatic spinnin

Comprehensive performance evaluation based on electromagnetic shielding properties of the weft-knitted fabrics made by stainless steel/cotton blended yarn

Electromagnetic shielding (EMS) fabric is an effective way to prevent electromagnetic (EM) radiation. However, the research about mechanism analysis of the fabrics’ structure, EM wave (EMW) incident direction, and EMW frequency on the EMS properties of knitted fabrics is discordant at present. Meanwhile, researchers are focused on improving the EMS efficiency of the fabric but rarely discussed the thermal-wet comfort of the fabric. Therefore, in this study a series of weft-knitted fabrics within stainless steel/cotton (30/70) blended yarns were knitted, and the effects of EMW incident direction, stitches, loop lengths, and frequency on EMS effectiveness (EMSE) were analyzed. Meanwhile, the EMS property, warmth retention property, air permeability, moisture permeability, and bursting strength were selected as the evaluation index to evaluate the comprehensive properties of the fabrics by fuzzy mathematics. The results showed that all factors had different degrees of influence on EMSE, and the weft inlay stitch had both the functionality and thermal-wet comfort, which was excellent EMSE in knitted fabric. These results are expected to provide a reference to the design of EMS weft-knitted fabrics

Anti-puncture, frigostable, and flexible hydrogel-based composites for soft armor

Cold adaptation is essential to the protective effect of soft armor and other protective materials because of the potential for prolonged exposure to freezing conditions in service, while the properties of flexible matrices are always affected by low temperatures. To integrate the good protection efficiency and excellent anti-freezing properties, polyvinyl alcohol (PVA), sodium alginate (SA), and glycerol (Gly) were selected to prepare a frigostable hydrogel in this study. Afterward, the hydrogel was laminated with aramid fabric to obtain a flexible anti-puncture composite that can be used at low temperatures. At −30 °C, the breaking strength and elongation of PVA/SA/Gly hydrogel reached 1.32 MPa and 330%, which was basically the same as at room temperature, indicating its excellent cold adaptation. Meanwhile, the maximum puncture resistance force and energy dissipation of the aramid/hydrogel composite at −30 °C were 56.88 N and 263.07 mJ, respectively, 289% and 184% higher than that of neat fabric, while the weight gain rate of the composite was only 40%. At room and low temperatures, the flexibility of the composite was only 5% and 8% lower than that of the neat fabric, respectively, and a helix shape of 360° could be formed and maintained under a small torsional force even at −30 °C

Regulation of dielectric and microwave absorption properties of needle-punched polyimide/carbon fiber nonwoven composites in X-band

The application of nonwoven fabrics in the field of microwave absorption is becoming more and more extensive because of its advantages of light weight, short manufacturing process and strong designability. In this article, polyimide and carbon fiber (PI/CF) nonwoven fabrics were prepared by needle punching process, and then they were immersed in water-based polyurethane (WPU) solution containing different contents of short carbon fiber (SCF, 0–3 mm) to prepare a series of PI/CF/WPU composites. As could be seen from the microscopic morphology that the materials were well impregnated by WPU, and the prepared composites had dense structures. The tensile strength and elongation at break of pure WPU were 13.4 MPa and 161.9%, respectively. The addition of 2 wt.% SCFs in WPU increased the tensile strength to 14.4 MPa by 7.4%, while the addition of 5 wt.% SCFs decreased the tensile strength by 8.2%. Adding 2 wt.% and 5 wt.% SCFs to WPU had little effect on improving the dielectric of pure WPU. But when the PI/CF nonwoven fabrics were added, the dielectric properties of the material greatly improved. The real and imaginary parts of the PI/CF/WPU were 20.2 and 9.5 at 8.2 GHz without SCF addition, 30.4 and 15.7 with 2 wt.% SCFs addition, and 47.2 and 182.8 with 5 wt.% SCFs addition. For PI/CF/WPU without SCF, the reflectivity in the entire X-band was lower than −10 dB in the thickness of 2–2.2 mm. When the thickness was 2.2 mm, the reflectivity reached the minimum value of −25 dB at 12.4 GHz