Bioactive Porous Particles as Biological and Physical Stimuli for Bone Regeneration.

Even though bony defects can be recovered to their original condition with full functionality, critical-sized bone injuries continue to be a challenge in clinical fields due to deficiencies in the scaffolding matrix and growth factors at the injury region. In this study, we prepared bone morphogenetic protein-2 (BMP-2)-loaded porous particles as a bioactive bone graft for accelerated bone regeneration. The porous particles with unique leaf-stacked morphology (LSS particles) were fabricated by a simple cooling procedure of hot polycaprolactone (PCL) solution. The unique leaf-stacked structure in the LSS particles provided a large surface area and complex release path for the sufficient immobilization of BMP-2 and sustained release of BMP-2 for 26 days. The LSS was also recognized as a topographical cue for cell adhesion and differentiation. In in vitro cell culture and in vivo animal study using a canine mandible defect model, BMP-2-immobilized LSS particles provided a favorable environment for osteogenic differentiation of stem cells and bone regeneration. In vitro study suggests a dual stimulus of bone mineral-like (leaf-stacked) structure (a physical cue) and continuously supplied BMP-2 (a biological cue) to be the cause of this improved healing outcome. Thus, LSS particles containing BMP-2 can be a promising bioactive grafting material for effective new bone formation.

Multifunctional Optical Device with a Continuous Tunability over 500 nm Spectral Range Using Polymerized Cholesteric Liquid Crystals.

We report that polymerization makes a robust, practically applicable multifunctional optical device with a continuous wavelength tunable over 500 nm spectral range using UV-polymerizable cholesteric liquid crystals (CLCs). It can be used as a circular polarizer generating an extremely high degree of circularly polarized light with |g| = 1.85~2.00. It can also be used for optical notch filters, bandwidth-variable (from ~28 nm to ~93 nm) bandpass filters, mirrors, and intensity-variable beam splitters. Furthermore, this CLC device shows excellent stability owing to the polymerization of CLC cells. Its performance remains constant for a long time (~2 years) after a high-temperature exposure (170 °C for 1 h) and an extremely high laser beam intensity exposure (~143 W/cm2 of CW 532 nm diode laser and ~2.98 MW/cm2 of Nd: YAG pulse laser operation for two hours, respectively). The optical properties of polymerized CLC were theoretically analyzed by Berreman's 4 × 4 matrix method. The characteristics of this device were significantly improved by introducing an anti-reflection layer on the device. This wavelength-tunable and multifunctional device could dramatically increase optical research efficiency in various spectroscopic works. It could be applied to many instruments using visible and near-infrared wavelengths.

ZnS Quantum Dot Based Acetone Sensor for Monitoring Health-Hazardous Gases in Indoor/Outdoor Environment.

This study reports the ZnS quantum dots (QDs) synthesis by a hot-injection method for acetone gas sensing applications. The prepared ZnS QDs were characterized by X-ray diffraction (XRD) and transmission electron microscopy analysis. The XRD result confirms the successful formation of the wurtzite phase of ZnS, with a size of ~5 nm. Transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and fast Fourier transform (FFT) images reveal the synthesis of agglomerated ZnS QDs with different sizes, with lattice spacing (0.31 nm) corresponding to (111) lattice plane. The ZnS QDs sensor reveals a high sensitivity (92.4%) and fast response and recovery time (5.5 s and 6.7 s, respectively) for 100 ppm acetone at 175 °C. In addition, the ZnS QDs sensor elucidates high acetone selectivity of 91.1% as compared with other intrusive gases such as ammonia (16.0%), toluene (21.1%), ethanol (26.3%), butanol (11.2%), formaldehyde (9.6%), isopropanol (22.3%), and benzene (18.7%) for 100 ppm acetone concentration at 175 °C. Furthermore, it depicts outstanding stability (89.1%) during thirty days, with five day intervals, for 100 ppm at an operating temperature of 175 °C. In addition, the ZnS QDs acetone sensor elucidates a theoretical detection limit of ~1.2 ppm at 175 °C. Therefore, ZnS QDs can be a promising and quick traceable sensor nanomaterial for acetone sensing applications.

Purulent pericarditis caused by group G streptococcus as an initial presentation of colon cancer.

Bacterial pericarditis has been recognized as a rare disease since the development of antibiotics. Usually, the disease is associated with underlying conditions or a seeding of infection elsewhere to the pericardium. Here we describe a case of group G streptococcal pericarditis as an initial presentation of colon cancer. A 52-yr-old man was admitted because of dyspnea. An electrocardiogram showed a diffuse ST-segment elevation and a two-dimensional echocardiogram showed a large amount of pericardial effusion. A pericardiocentesis was done and purulent fluid was drained. Group G streptococci was cultured in pericardial fluid. The patient was treated with antibiotics and pericardiostomy with saline irrigation. A colonoscopy revealed a small mass with moderately differentiated adenocarcinoma in rectosigmoid colon. He underwent a mucosectomy and was recovered without any complication.