Nanoscale modification of porous gelatin scaffolds with chondroitin sulfate for corneal stromal tissue engineering

Recent studies reflect the importance of using naturally occurring biopolymers as three-dimensional corneal keratocyte scaffolds and suggest that the porous structure of gelatin materials may play an important role in controlling nutrient uptake. In the current study, the authors further consider the application of carbodiimide cross-linked porous gelatin as an alternative to collagen for corneal stromal tissue engineering. The authors developed corneal keratocyte scaffolds by nanoscale modification of porous gelatin materials with chondroitin sulfate (CS) using carbodiimide chemistry. Scanning electron microscopy/energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy showed that the amount of covalently incorporated polysaccharide was significantly increased when the CS concentration was increased from 0% to 1.25% (w/v). In addition, as demonstrated by dimethylmethylene blue assays, the CS content in these samples was in the range of 0.078–0.149 nmol per 10 mg scaffold. When compared with their counterparts without CS treatment, various CS-modified porous gelatin membranes exhibited higher levels of water content, light transmittance, and amount of permeated nutrients but possessed lower Young’s modulus and resistance against protease digestion. The hydrophilic and mechanical properties of scaffolds modified with 0.25% CS were comparable with those of native corneas. The samples from this group were biocompatible with the rabbit corneal keratocytes and showed enhanced proliferative and biosynthetic capacity of cultured cells. In summary, the authors found that the nanoscale-level modification has influence on the characteristics and cell-material interactions of CS-containing gelatin hydrogels. Porous membranes with a CS content of 0.112 ± 0.003 nmol per 10 mg scaffold may hold potential for use in corneal stromal tissue engineering

Social Capital and Technological Literacy in Taiwan

The burgeoning interest in social capital within the technology community represents a welcome move towards a concern for the social elements of technological adaptation and capacity. Since technology plays an ever larger role in our daily life, it is necessary to articulate social capital and its relationship to technological literacy. A nationwide data was collected by area sampling, and position generator was used to measure social capital. Regression model was constructed for technological literacy. Age, gender, education, income, web access, and social capital were included as independent variables. The results show that age, gender, education, web access, and social capital were good predictors of technological literacy. It is concluded that social capital is helpful in coping with rapid technological change. Theoretical and empirical implications and future research are discussed

Donor Site Morbidity Associated with Cancellous Bone Harvest from the Anterior Iliac Crest: Using a Mini-Access Approach and Literature Review

Introduction: The anterior iliac crest is a popular donor sites for cancellous bone in alveolar cleft reconstruction. Potential problems such as donor site pain, restricted ambulation, and sensory nerve injury, are common drawbacks. We developed a mini-access approach to harvest cancellous bone graft from the iliac crest and reviewed the donor site morbidity in the literature.Methods: We reviewed the previously-collected data from patients who underwent alveolar bone grafting using the mini-access approach from the iliac crest in 2005, which was the second year in which we used this method. Donor site morbidity was recorded and analyzed. Data from a total of 40 patients were reviewed.Results: 28 patients were male and 12 were female with a mean age of 10. Thirty-three patients had a unilateral cleft, and 7 patients had bilateral clefts. The average bone graft volume was 5.35 ml, while the average length of hospitalization was 4.55 days. Suspected lateral femoral cutaneous nerve injury occurred in 10% of the cases.Conclusion: Compared to the literature, although we could not conclude that the mini-access approach is absolutely better than the other methods, it provides an easy, alternative way without special equipments to decrease the donor site morbidity

Cyclosporine A Eye Drop-Induced Elongated Eyelashes: A Case Report

Purpose: The most common ocular adverse event following the use of cyclosporine A (CsA) 0.05% ophthalmic emulsion is ocular burning (17%). Other adverse effects that have been reported include conjunctival hyperemia (1–5%), discharge, epiphora, eye pain, foreign body sensation, pruritus, stinging and blurred vision. Here, we report a specific side effect of CsA, namely eye drop-induced eyelash elongation in a patient with refractory giant papillary conjunctivitis. Design: Observational case report. Methods: Case report and review of the literature. Results: A 32-year-old female with giant papillary conjunctivitis on the left eye, who had undergone papillectomy 3 years previously and was refractory to topical steroid therapy, was treated with CsA 0.05% ophthalmic emulsion (Restasis) 4 times a day, preservative-free artificial tears and gentamicin ophthalmic solution in the left eye. After 5 months of topical CsA treatment, elongated eyelashes of her left eye were observed without other adverse effects. Conclusion: Although hypertrichosis and trichomegaly have been documented in the literature as side effects of systemic CsA, topical CsA 0.05% eye drop-induced elongated eyelashes have not been reported, and we believe ophthalmologists should be mindful and inform patients about this specific side effect

Recurrent chronic subdural hemorrhage due to cervical spinal CSF leak in a young adult: Report of a case

SummaryNontraumatic intracranial subdural hemorrhage may result from disorders at remote anatomic sites. Here, we report a young adult who suffered from bilateral subdural hematoma without antecedent head injury. The subdural hematoma did not resolve after surgical drainage. The symptom of postural headache prompted a contrast-enhanced magnetic resonance imaging (MRI) examination of the brain, which revealed signs indicative of intracranial hypotension. Subsequently, MRI of the spine demonstrated leakage of cerebrospinal fluid (CSF) in the upper cervical spine region. The patient recovered after conservative treatment. A review of the patient’s medical history revealed that the patient had chiropractic therapy on his neck 2 months prior to admission. Intracranial hypotension due to spinal CSF leak is a rare cause of subdural hemorrhage, yet it should be considered in the absence of head trauma

Optical Properties and Enhanced Photothermal Conversion Efficiency of SiO2/A-Dlc Selective Absorber Films for A Solar Energy Collector Fabricated by Unbalance Sputter

AbstractSolar energy could become the most attractive alternative energy source. In this study we test an attractive new candidate material for solar energy collectors. It can be found that the higher the gas pressure is, the higher the sp2/sp3 area ratio, the greater the sputtering rate and the greater the optical absorption. The photothermal conversion efficiency of a SiO2 coating on the amorphous diamond-like carbon (a-DLC) selective absorber films deposited on the Cr/mirror like Al substrate is 93.2% as the film thickness of a SiO2 coating is 105nm. The coatings also increase the protective properties for a longer service life. This makes the SiO2 coated a-DLC film a promising new candidate material for solar selective absorber films. The SiO2/a-DLC selective absorber films also were deposited on the Al extrusion substrates

In Vitro Response of Retinal Pigment Epithelial Cells Exposed to Chitosan Materials Prepared with Different Cross-Linkers

The interaction between cells and biopolymers is the evaluation indicator of the biocompatibility of materials. The purpose of this work was to examine the responses of retinal pigment epithelial (RPE) cells to genipin (GP) or glutaraldehyde (GTA) cross-linked chitosan by means of cell viability assays, cytokine expression analyses, and apoptosis assays. Evaluations of non-cross-linked chitosan were conducted simultaneously for comparison. Both GP and GTA treated samples with the same extent of cross-linking (around 80%) were prepared by varying cross-linking time. Our results showed that GP cross-linking was carried out by either radical polymerization of the monomers or SN2 nucleophilic substitution reaction involving the replacement of the ester group on the monomer with a secondary amide linkage. On the other hand, GTA could react with free amino groups of chitosan, leading to the formation of either the Schiff bases or the Michael-type adducts with terminal aldehydes. The biocompatibility of non-cross-linked chitosan membranes was demonstrated by the absence of any signs of toxicity or inflammation reaction. The present study showed that the ARPE-19 cells exposed to GTA cross-linked chitosan membranes had significantly higher cytotoxicity, interleukin-6 levels, and number of TUNEL-positive nuclei than did those exposed to GP treated samples. In addition, the materials modified with GTA trigger apoptosis at an early stage and may induce toxicity in the RPE cells later. The findings suggest that while the chitosan molecules bridged by GP are satisfactorily cytocompatible, the counterparts treated by GTA do not seem to be tolerated. In terms of material safety, the GP cross-linked chitosan may be compatible with human RPE cells and may have a potential application as delivery carriers in the treatment of posterior segment diseases