Arc discharge method to fabricate large concave structures for open-access fiber Fabry-Pérot cavities.

We present a novel micro-fabrication technique for creating concave surfaces on the endfacets of photonic crystal fibers. A fiber fusion splicer is used to generate arc discharges to melt and reshape the fiber endfacet. This technique can produce large spherical concave surfaces with roughness as low as 0.12 nm in various types of photonic crystal fibers. The deviation of fabricated surface and a spherical profile in the region of 70 µm in diameter is less than 50 nm. The center of the concave surface and the fiber mode field are highly coincident with a deviation less than 500 nm. Finesse measurements have shown that a Fabry-Pérot cavity composed of the fiber fabricated using this method and a plane mirror maintains finesse of 20000. This method is easy to replicate, making it a practical and efficient approach to fabricate concave surface on fibers for open-access fiber Fabry-Pérot cavities.

The role and mechanism of flavonoid herbal natural products in ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory disease of the intestine that presents clinically with abdominal pain, mucopurulent stools, and posterior urgency. The lesions of UC are mainly concentrated in the rectal and colonic mucosa and submucosa. For patients with mild to moderate UC, the best pharmacological treatment includes glucocorticoids, immunosuppressants, antibiotics, and biologics, but the long-term application can have serious toxic side effects. Currently, nearly 40% of UC patients are treated with herbal natural products in combination with traditional medications to reduce the incidence of toxic side effects. Flavonoid herbal natural products are the most widely distributed polyphenols in plants and fruits, which have certain antioxidant and anti-inflammatory activities. Flavonoid herbal natural products have achieved remarkable efficacy in the treatment of UC. The pharmacological mechanisms are related to anti-inflammation, promotion of mucosal healing, maintenance of intestinal immune homeostasis, and regulation of intestinal flora. In this paper, we summarize the flavonoid components of anti-ulcerative colitis and their mechanisms reported in the past 10 years, to provide a basis for rational clinical use and the development of new anti-ulcerative colitis drugs.

Engineering of glycerol utilization in Pseudomonas chlororaphis GP72 for enhancing phenazine-1-carboxylic acid production.

Glycerol is a by-product of biodiesel, and it has a great application prospect to be transformed to synthesize high value-added compounds. Pseudomonas chlororaphis GP72 isolated from the green pepper rhizosphere is a plant growth promoting rhizobacteria that can utilize amount of glycerol to synthesize phenazine-1-carboxylic acid (PCA). PCA has been commercially registered as "Shenqinmycin" in China due to its characteristics of preventing pepper blight and rice sheath blight. The aim of this study was to engineer glycerol utilization pathway in P. chlororaphis GP72. First, the two genes glpF and glpK from the glycerol metabolism pathway were overexpressed in GP72ANO separately. Then, the two genes were co-expressed in GP72ANO, improving PCA production from 729.4 mg/L to 993.4 mg/L at 36 h. Moreover, the shunt pathway was blocked to enhance glycerol utilization, resulting in 1493.3 mg/L PCA production. Additionally, we confirmed the inhibition of glpR on glycerol metabolism pathway in P. chlororaphis GP72. This study provides a good example for improving the utilization of glycerol to synthesize high value-added compounds in Pseudomonas.

Evaluation of Decellularized Bovine Tendon Sheets for Achilles Tendon Defect Reconstruction in a Rabbit Model.

BACKGROUND: Achilles tendon (AT) defects frequently occur in trauma and chronic injuries. Currently, no method can satisfactorily reconstruct the AT with completely restored function. PURPOSE: To evaluate the postoperative outcomes of AT defect reconstruction with decellularized bovine tendon sheets (DBTSs) in a rabbit model. STUDY DESIGN: Controlled laboratory study. METHODS: DBTSs were prepared from bovine tendons after compression, decellularization, antigen extraction, freeze drying, and sterilization. Platelet-rich plasma (PRP) was obtained by differential centrifugation. Sixty-three rabbits were used in this study, and the AT defect model was created bilaterally. All rabbits were divided into 3 groups (n = 21). In the DBTS group and the DBTS + PRP group, 2-cm-long AT was excised and reconstructed by DBTSs or PRP-treated DBTSs. In the control group, the rabbits underwent AT transection, and stumps were sutured. After surgery, all rabbits were assessed by ultrasonography and magnetic resonance imaging and then sacrificed for histological examination and biomechanical testing at 4, 8, or 12 weeks. RESULTS: Gross observations demonstrated the absence of immunologic incompatibility and rejection. Histological examination showed that DBTSs promoted host cell infiltration and new fibrous tissue integration as compared with the control group. In each group, there was an AT-like structure formation and aligned collagen fiber deposition at 12 weeks. Mechanical properties of the reconstructed AT were not significantly different among the 3 groups at 4, 8, and 12 weeks after surgery ( P > .05). Ultrasonography and magnetic resonance imaging results illustrated that the reconstructed AT from each group maintained remodeling, and there was no significant difference in the echogenicity scoring ( P > .05) and percentages of good and excellent ( P > .05) among the 3 groups. CONCLUSION: DBTSs, which retain the native tendon structure and bioactive factors, had the ability to remodel and integrate into the rabbit AT and improve the healing process. CLINICAL RELEVANCE: DBTSs could serve as an effective bioscaffold to reconstruct AT defects.

Fabrication and characterization of a decellularized bovine tendon sheet for tendon reconstruction.

Obtaining a performing decellularized tendon scaffold with proper dimensions and adequate availability is highly desirable. However, the combined study of complete decellularization and detailed characterization of native tendon extracellular matrix (ECM) from large animals is still lacking. In the present study, we developed a new decellularization protocol, including physical methods and enzymatic solutions for processing bovine Achilles tendons, and produced a decellularized bovine tendon sheet (DBTS) scaffold for tendon reconstruction. The decellularization effectiveness was demonstrated by DNA quantification and histological qualification. The removal of the alpha-gal epitopes was confirmed by ELISA analysis and immunohistochemical staining. After decellularization, there were no significant alterations of the native tendon extracellular matrix (ECM) properties, including the internal ultrastructure, biochemical compositions such as collagen, glycosaminoglycans (GAGs), basic fibroblast growth factor (bFGF) and transforming growth factor-ß1 (TGF-ß1), fibronectin and decorin, as well as substantial mechanical strength. Furthermore, the DBTS scaffold showed no cytotoxic and promoted the proliferation of NIH-3T3 fibroblasts in vitro. When implanted into rat subcutaneous tissue, the DBTS scaffold displayed excellent histocompatibility in vivo. Our results, while offering a new decellularization protocol for large tendons, can provide a promising biologic scaffold with a combination of mechanical strength and tendon ECM bioactive factors that may have many potential applications in tendon reconstruction. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2299-2311, 2017.

Mesenchymal Stem Cells Derived from Peripheral Blood Retain Their Pluripotency, but Undergo Senescence During Long-Term Culture.

Peripheral blood-derived mesenchymal stem cells (PB-MSCs) show promise as a source of cells for autologous transplantation because they can be harvested through minimally invasive procedures. To ensure adequate numbers of cells for transplantation and tissue regeneration, PB-MSCs must first be cultured and expanded in vitro, but whether long-term passage modifies their properties has been poorly understood. In this study we triggered production of PB-MSCs in rabbits using granulocyte colony-stimulating factor (G-CSF) and AMD3100, and then isolated and expanded the cells in culture until they reached a state of senescence, usually after about 20 passages. Cultures of low-, middle-, and high-passage numbers were compared in terms of morphology, proliferative capacity, phenotype, differentiation potential, apoptosis, metabolic indicators, and senescence. As passage number increased, MSCs retained their elongated spindle shape, but became larger and flatter, slowed in growth gradually, and increased proportion of cells showed G1 arrest. The proportions of apoptotic cells, production of reactive oxygen species (ROS), and ADP/ATP ratio increased with passage number. Expression of senescence-associated ß-galactosidase increased, while telomerase activity decreased. On the other hand, cultures did not show significant changes in phenotype or lose their ability to differentiate into three lineages as passage number increased. These results suggest that PB-MSCs maintain their stem cell properties during prolonged culturing, but they undergo senescence that may be due to apoptosis and production of ROS. These findings may help to standardize in vitro production of PB-MSCs for tissue engineering.

[Research and implementation of the registry system of multimedia EMR sharing based on XDS-I].

Referring to XDS-I and RIM of ebXML, we have built a registry system for electronic medical records sharing which is introduced, in this paper.