An assessment of physical properties and the viability of osteoblast-like cells of cefazolin-impregnated calcium sulfate bone-void filler.

Calcium sulfate, an injectable and biodegradable bone-void filler, is widely used in orthopedic surgery. Based on clinical experience, bone-defect substitutes can also serve as vehicles for the delivery of drugs, for example, antibiotics, to prevent or to treat infections such as osteomyelitis. However, antibiotic additions change the characteristics of calcium sulfate cement. Moreover, high-dose antibiotics may also be toxic to bony tissues. Accordingly, cefazolin at varying weight ratios was added to calcium sulfate samples and characterized in vitro. The results revealed that cefazolin changed the hydration reaction and prolonged the initial setting times of calcium sulfate bone cement. For the crystalline structure identification, X-ray diffractometer revealed that cefazolin additive resulted in the decrease of peak intensity corresponding to calcium sulfate dihydrate which implying incomplete phase conversion of calcium sulfate hemihydrate. In addition, scanning electron microscope inspection exhibited cefazolin changed the morphology and size of the crystals greatly. A relatively higher amount of cefazolin additive caused a faster degradation and a lower compressive strength of calcium sulfate compared with those of uploaded samples. Furthermore, the extract of cefazolin-impregnated calcium sulfate impaired cell viability, and caused the death of osteoblast-like cells. The results of this study revealed that the cefazolin additives prolonged setting time, impaired mechanical strength, accelerated degradation, and caused cytotoxicity of the calcium sulfate bone-void filler. The aforementioned concerns should be considered during intra-operative applications.

Antifibrotic Effect of Bletilla striata Polysaccharide-Resveratrol-Impregnated Dual-Layer Carboxymethyl Cellulose-Based Sponge for The Prevention of Epidural Fibrosis after Laminectomy.

The application of antifibrotic materials can alleviate epidural fibrosis by restricting excessive fibroblast proliferation and mitigating scar tissue formation. Here, a biodegradable carboxymethyl cellulose (CMC)-Bletilla striata polysaccharide (BSP)-resveratrol (RES) sponge was fabricated to inhibit scar tissue formation post laminectomy surgery. Fibroblasts NIH/3T3, myoblasts C2C12, neural cells PC-12, and Schwann cells RSC96 were used to evaluate the in vitro cytocompatibility. Laminectomies on 10 Sprague-Dawley rats with/without the application of the CMC-BSP-RES sponge were performed. The severity of adhesion between the dura mater and formed scar tissue was qualitatively scored. All cell lines exhibited good viability with no significant difference in cytotoxicity when cultured with variable extractions of the CMC-BSP-RES sponge. S100a4 and P4hb expressions were downregulated in NIH/3T3 cultured in the CMC-BSP-RES sponge, implying that this sponge potentially inhibits fibroblast activity. No post-operative shrinkage or dura mater expansion along the surgical site was detected. The peel-off tests revealed that the tenacity of adhesion de-creased. Histopathological examinations verified that the average number of fibroblasts in the CMC-BSP-RES group considerably decreased. The CMC-BSP-RES sponge is a biocompatible and effective material for alleviating post-operative epidural fibrosis and mitigating fibroblast expression following laminectomy.

Curcumin-Loaded Hydrophobic Surface-Modified Hydroxyapatite as an Antioxidant for Sarcopenia Prevention.

Oxidative stress and later-induced chronic inflammation have been reported to play an important role on the progression of sarcopenia. Current treatments for sarcopenia are mainly administered to patients whom sarcopenia already developed. However, there has been no promising results shown in therapy. Therefore, the development of therapeutic and preventive strategies against sarcopenia would be necessary. Curcumin is a traditional medicine that possesses anti-inflammatory and antioxidative properties. In the present study, hydroxyapatite was subjected to hydrophobic surface modifications for curcumin loading (Cur-SHAP). It was, subsequently, utilized for delivery to the patient's body via intramuscular injection in order to achieve constant release for more than 2 weeks, preventing the progression of the sarcopenia or even leading to recovery from the early stage of the illness. According to the results of WST-1, LIVE/DEAD, DCFDA, and gene expression assays, Cur-SHAP exhibited good biocompatibility and showed great antioxidant/anti-inflammatory effects through the endocytic pathway. The results of the animal studies showed that the muscle endurance, grip strength, and fat/lean mass ratio were all improved in Cur-SHAP-treated rats from LPS-induced sarcopenia. In summary, we successfully synthesized hydrophobic surface modification hydroxyapatite for curcumin loading (Cur-SHAP) and drug delivery via the IM route. The LPS-induced sarcopenia rats were able to recover from disease after the Cur-SHAP treatment.

Conservative treatment of recurrent symptoms of an incomplete, atypical femoral fracture associated with glucocorticoid, bisphosphonate, and denosumab therapy in a patient with chronic obstructive pulmonary disease.

Background: Patients with chronic obstructive pulmonary disease have a high prevalence of osteoporosis, and different osteoporosis drugs are used to prevent fractures in these patients. Although the overall incidence of complete or incomplete, atypical femoral fracture (AFF) is low, long-term use of antiresorptive agents is associated with an increased risk of developing AFF. Methods: We present a patient with chronic obstructive pulmonary disease with recurrent symptoms of an incomplete AFF who had been treated with glucocorticoids, and sequentially with alendronate, zoledronic acid, strontium ranelate, raloxifene, denosumab and finally with teriparatide. The first episode occurred before osteoporosis therapies, the second after bisphosphonate treatments, and the third under denosumab. Results: Although her symptoms resolved along with gradually healing of fracture lines after conservative treatment without surgical intervention, progressive varus deformity of the proximal femur may have contributed to recurrence of AFF. Conclusion: Early treatment with anabolic agents and prophylactic fixation of incomplete AFF may alleviate symptoms and prevent recurrences.

Solid-State Carbon-Doped GaN Schottky Diodes by Controlling Dissociation of the Graphene Interlayer with a Sputtered AlN Capping Layer.

Carbon-doped GaN (GaN:C) Schottky diodes are prepared by controlling the destruction status of the graphene interlayer (GI) on the substrate. The GI without a sputtered AlN capping layer (CL) was destroyed because of ammonia precursor etching behavior in a high-temperature epitaxy. The damaged GI, like nanographite as a solid-state carbon doping source, incorporated the epitaxial growth of the GaN layer. The secondary ion mass spectroscopy depth profile indicated that the carbon content in the GaN layer can be tuned further by optimizing the sputtering temperature of AlN CL because of the better capping ability of high crystalline quality AlN CL on GI being achieved at higher temperature. The edge-type threading dislocation density and carbon concentration of the GaN:C layer with an embedded 550 °C-grown AlN CL on a GI substrate can be significantly reduced to 2.28 × 109 cm-2 and ∼2.88 × 1018 cm-3, respectively. Thus, a Ni-based Schottky diode with an ideality factor of 1.5 and a barrier height of 0.72 eV was realized on GaN:C. The series resistance increased from 28 kΩ at 303 K to 113 kΩ at 473 K, while the positive temperature coefficient (PTC) of series resistance was ascribed to the carbon doping that induced the compensation effect and lattice scattering effect. The decrease of the donor concentration was confirmed by temperature-dependent capacitance-voltage (C-V-T) measurement. The PTC characteristic of GaN:C Schottky diodes created by dissociating the GI as a carbon doping source should allow for the future use of high-voltage Schottky diodes in parallel, especially in high-temperature environments.

InGaN-Based Light-Emitting Diodes Grown on a Micro/Nanoscale Hybrid Patterned Sapphire Substrate.

A hybrid patterned sapphire substrate (hybrid-PSS) was prepared using an anodic aluminum oxide etching mask to transfer nanopatterns onto a conventional patterned sapphire substrate with microscale patterns (bare-PSS). The threading dislocation (TD) suppression of light-emitting diodes (LEDs) grown on a hybrid-PSS (HP-LED) exhibits a smaller reverse leakage current compared with that of LEDs grown on a bare-PSS (BP-LED). The strain-free GaN buffer layer and fully strained InGaN active layer were evidenced by cross-sectional Raman spectra and reciprocal space mapping of the X-ray diffraction intensity for both samples. The calculated piezoelectric fields for both samples are close, implying that the quantum-confined Stark effect was not a dominant mechanism influencing the electroluminescence (EL) peak wavelength under a high injection current. The bandgap shrinkage effect of the InGaN well layer was considered to explain the large red-shifted EL peak wavelength under high injection currents. The estimated LED chip temperatures rise from room temperature to 150 °C and 75 °C for BP-LED and HP-LED, respectively, at a 600-mA injection current. This smaller temperature rise of the LED chip is attributed to the increased contact area between the sapphire and the LED structural layer because of the embedded nanopattern. Although the chip generates more heat at high injection currents, the accumulated heat can be removed to outside the chip effectively. The high diffuse reflection (DR) rate of hybrid-PSS increases the escape probability of photons, resulting in an increase in the viewing angle of the LEDs from 130° to 145°. The efficiency droop was reduced from 46% to 35%, effects which can be attributed to the elimination of TDs and strain relaxation by embedded nanopatterns. In addition, the light output power of HP-LED at 360-mA injection currents exhibits a ∼ 22.3% enhancement, demonstrating that hybrid-PSSs are beneficial to apply in high-power LEDs.