A collagen film with micro-rough surface can promote the corneal epithelization process for corneal repair.

Corneal disease is a major cause of blindness and keratoplasty is an effective treatment method. A freeze-dried collagen film (FD-Col) with micro-rough surface structure for corneal epithelial repair was reported in our previous studies. In this research, we conducted a more comprehensive study on the FD-Col film. Besides with excellent mechanical property and optical transparency, the FD-Col film also has good penetrating ability in nutrient solutions. The permeability coefficient of the FD-Col in NaCl and tryptophan solution is (2.58 ±â€¯0.47) × 10-6 cm2/s and (2.67 ±â€¯0.13) × 10-7 cm2/s, respectively. In addition, the morphology change of the FD-Col film before and after water absorption is relatively stable suggesting that this film can be fabricated with various dimensions easily. Moreover, corneal lamellar keratoplasty shows that the FD-Col film can be sutured in rabbit's ocular surface and the re-epithelization process in vivo is complete in about 12 days, and the transparency is restored quickly in the first month. Corneal rejection reaction, neovascularization and keratoconus are not observed within 2 months. This FD-Col film, which can be prepared in large quantities and at low cost, should have potential application in corneal repair in the future.

Sharp inequalities for tangent function with applications.

In the article, we present new bounds for the function [Formula: see text] on the interval [Formula: see text] and find sharp estimations for the Sine integral and the Catalan constant based on a new monotonicity criterion for the quotient of power series, which refine the Redheffer and Becker-Stark type inequalities for tangent function.

Gentamicin modified chitosan film with improved antibacterial property and cell biocompatibility.

Gentamicin modified chitosan film (CS-GT) was produced using a three-step procedure comprising: (i) the chitosan solution was air-dried to form a chitosan (CS) film, (ii) using citric acid to generate the amide and carboxyl groups on the surface of CS, (iii) the CS with surface carboxyl groups was modified by grafting of gentamicin. After modification, this CS-GT film has excellent hydrophilicity and biocompatibility. It is very evident that the gentamicin grafting treatment significantly improves the antibacterial properties of the CS film. Our preliminary results suggest that this novel gentamicin modified chitosan film, which can be prepared in large quantities and at low cost, should have potential application in biomedical applications.

Improving the moisturizing properties of collagen film by surface grafting of chondroitin sulfate for corneal tissue engineering.

Cornea disease is the second cause of blindness and keratoplasty is the most commonly performed option for visual rehabilitation of patients with corneal blindness. However, the clinical treatment has been drastically limited due to a severe shortage of high-quality donor corneas. Although collagen film with outstanding biocompatibility has promising application in corneal tissue engineering, the moisturizing properties of collagen-based materials must be further improved to satisfy the requirements of clinical applications. This paper describes a novel collagen-based film with high moisture capacity reinforced by surface grafting of chondroitin sulfate. The collagen-chondroitin sulfate (abbreviated as Col-CS) film was analyzed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy and its hydrophilic property, moisture retention, optical property, and mechanical performance had been tested. The moisture-retaining capacity is found to be improved with the introduction of chondroitin sulfate, and the Col-CS membrane performs better mechanical properties than the collagen film. Moreover, the modified film proves excellent biocompatibility for the proliferation of human corneal epithelial cells in vitro. This Col-CS film with good moisturizing properties can reduce the risk of xerophthalmia and is expected to increase the implant success rate in clinic patients with corneal defects.

Modification of properties of old newspaper pulp with biological method.

Modification of properties of old newspaper (ONP) deinked pulp with laccase and histidine was investigated. It was found that the optimum conditions for laccase-histidine treatment were: the concentration of laccase 0.9 U/g dry pulp, the concentration of histidine 1% relative to the dry pulp, room temperature, reaction time 1.5h, pH 7, the pulp consistency 5% and O(2) atmosphere. The results also showed that, in the optimum conditions, compared to the control pulp, the wet tensile strength, the carboxyl group content and water retention value of ONP treated with laccase and histidine were increased by 55.1%, 39.1% and 45.7%, respectively. Moreover, environmental scanning microscope images showed that more collapse and more fibrillation were observed on the laccase-histidine-treated fiber surface than the control samples, which led to form better bonding between fibers in handsheets resulting in the increase of the paper strength of laccase-histidine-treated ONP pulp.