No abstract

Phosphorus-containing flame retardant (HBAEA-DOPO) for epoxy resin was synthesized by addition reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) with bis[2-(4-hydroxybenzylideneamino) ethyl]amine (HBAEA) that was synthesized via 4-hydroxybenzaldehyde with diethylenetriamine. HBAEA-DOPO was mixed with 4,4 0-diaminodiphenyl sulfone to co-cure the epoxy resin of diglycidyl ether bisphenol A. The silane modified nano-silica (nano-SiO 2) was used to reinforce the epoxy resin. Thermal stability and dynamic mechanical properties of the cured epoxy materials were studied with the use of thermogravimetric analysis and dynamic mechanical thermal analysis. Flame retardance and burning behavior were evaluated by the limiting oxygen index (LOI), vertical burning test, and the cone calorimetry. The cured epoxy materials have excellent thermal stability, and the temperatures at the maximum weight loss rate are over 384.0 C. The characteristic temperature corresponding to 5.00 wt% of thermal decomposition reaches 341.5 C as 1.00 wt% of phosphorus content is loaded. Flame retardant grade meets the V-0 level. The fire residue mass gradually increases with HBAEA-DOPO and nano-SiO 2. The characteristics of high flame retardance and smoke suppression of HBAEA-DOPO and nano-SiO 2 on the cured epoxy composites have been demonstrated to be related to char formation and intumescent flame retardance in the condensed phase.

ObjectiveThe aim of this study was to investigate the optimal timing for the resection of heterotopic ossification (HO) of the elbow.MethodsWe retrospectively reviewed 42 patients who were treated operatively for heterotopic ossification of the elbow from March 2010 to December 2014 at our institution. The patients were divided into early (before 12 months) and late (after 12 months) excision groups. In the early excision group (17 patients), the average time from the initial injury to HO excision was 7.4 (3–11) months, and in the late excision group (25 patients), the average time was 33.5 (12–240) months. Every patient was evaluated by range of motion (ROM), the Mayo Elbow Performance Score (MEPS), postoperative complications and HO recurrence.ResultsThe preoperative mean ROM in the late excision group was greater than that of the early excision group, suggesting that the ROM is expected to increase even without surgery. Both early and late surgery increased ROM and MEPS, but early surgery improved ROM and MEPS more than late surgery did (p < .05).ConclusionsEarly excision of HO can provide better elbow function, as indicated by ROM and MEPS. Considering that there were no notable differences in postoperative ROM and MEPS, HO recurrence, or postoperative complications, we concluded that early excision is safe and that the time from an elbow injury to surgery may be shortened.Level of EvidenceLevel III, therapeutic study.

Interfacial rheology is crucial in dictating morphology and ultimate properties of particle-stabilized polymer blends, but is challenging to be determined. In this study, a fully polymeric dumbbell-shaped Janus nanoparticle (JNP) of polymethyl methacrylate (PMMA) and polystyrene (PS) spheres with equal sizes (∼80 nm) was prepared and used as an efficient compatibilizer for PMMA/PS blends. The JNPs were preferentially localized at the PMMA/PS interface, thereby reducing the interfacial tension and refining the morphology in both droplet-matrix and co-continuous type blends, whereby a JNP concentration ∼2.5 wt % is sufficient to reach a saturation in droplet size reduction due to compatibilization. Based on the linear viscoelastic moduli and corresponding relaxation spectra (H(τ)*τ) of JNP-compatibilized droplet-matrix blends, besides the droplet shape relaxation time (τF), a longer relaxation time (τβ), typically related to interfacial viscoelasticity, was readily identified. The dependence of τβ on the JNP concentration (W JNPs) was significantly dominated by the droplet size reduction induced by the JNP compatibilization, with τβ decreasing with increasing W JNPs. The viscoelastic properties extracted from τβ typically originate from a combination of gradients in interfacial tension due to the particle redistribution at the droplet interface (Marangoni stresses) and the deviatoric stresses of intrinsic rheological origin. The latter originate from the intrinsic viscoelasticity of the particle-laden interface, which is enhanced by particle jamming and particle–polymer interactions, such as entanglements between chains from the polymeric spheres and those penetrating from the bulk into the spheres. To address the challenge of isolating these contributions, a JNP-sandwiched PMMA/PS multilayer structure was designed to exclude the effect of Marangoni stresses and droplet curvature, thus having no τF but a new relaxation (τ′β), which characterizes the contribution of intrinsic interfacial viscoelasticity. The τ′β was observed to increase with JNP coverage (Σ) following the Vogel–Fulcher–Tammann model that is typically used to describe the divergent behavior of the “cage” effect in classical colloidal glasses. Moreover, a multimode Maxwell model fitting allows to split the interfacial relaxation into the confined diffusion of JNPs within their cage and the entanglements between the JNPs and the bulk.

No abstract

V, therapeutic study.

Bio‐absorbable polymers are widely desired to be applied and used as biomaterials for surgery hemostatic and medical tissue engineering devices. Ring‐opening copolymerization reaction was applied to synthesize poly(ethylene succinate‐co‐glycolide) (PES‐b‐PGA). Stannous octoate was used as a catalyst whereas poly(ethylene succinate) was used as a macro‐initiator to react with glycolide. PES‐b‐PGA was then used as a compatibilizer to prepare the blend biomaterial of PPDO/PLGA/PES‐b‐PGA by melt blending poly(p‐dioxanone) (PPDO) with poly(lactide‐co‐glycolide) (PLGA). This would enhance the interactions of the inter‐molecular chains and intra‐molecular segments thus improving the compatibility. To obtain the biomaterial of PPDO/PLGA/PES‐b‐PGA with a regulated and controlled degradation and/or hydrolysis period, various ratios of PPDO, PLGA, and PES‐b‐PGA was blended. Behaviors of the thermal and in vitro simulated degradation, biological compatibility, cytotoxicity and subcutaneous implantation of PPDO/PLGA/PES‐b‐PGA were investigated. The results show that the in vitro hydrolytic degradation cycle is consistent with the wound healing time and that the biomaterial has slight cytotoxicity and it will do good to the cell proliferation, with 1 grade of cytotoxicity and the relative growth rate being the range from 92.5% to 96.2%. The implantation of the biomaterial into the rabbits' ears will not adversely affect the wound healing and the tissues surrounding the implanted sites. Therefore, the biomaterial has good biocompatibility and potential applications in medical tissue engineering devices.

BackgroundExtraskeletal osteosarcoma (ESOS) is a highly malignant osteosarcoma that occurs in extraskeletal tissues. It often affects the soft tissues of the limbs. ESOS is classified as primary or secondary ESOS. Case presentationwe report a case of primary hepatic osteosarcoma in a 76-year-old male patient. The patient had a giant cystic-solid mass in the right liver that was evident on ultrasound and computed tomography. Postoperative pathology and immunohistochemistry of the mass, which was surgically removed, suggested fibroblastic osteosarcoma. No other abnormal lesions were found. Therefore, the patient was diagnosed with primary hepatic osteosarcoma. The hepatic osteosarcoma reoccurred 48 days after surgery, resulting in significant compression and narrowing of the hepatic segment of the inferior vena cava. Consequently, the patient underwent stent implantation in the inferior vena cava and transcatheter arterial chemoembolization. Unfortunately, the patient died of postoperative multiple organ failure.ConclusionsHepatic osteosarcoma is a rare mesenchymal tumor with a short course and a high likelihood of metastasis and recurrence. If a biopsy were to return osteoid in a large liver tumor, ESOS would be suspected. However, there is no evidence-based treatment plan to date. Surgical resection combined with adjuvant chemoradiotherapy seems to be the best treatment option.