Sensitive detection of PDT-induced cell damages with luminescent oxygen nanosensors.

In this work luminescent nanosensors specifically created for intracellular oxygen (ic-O2) were utilized to assess photodynamic therapy (PDT) -induced cell damages. Firstly, ic-O2 was demonstrated to be consumed much faster than extracellular O2 with respective O2 nanosensors. Using the ic-O2 nanosensors, PDT-treated cells with different degree of impairment were then resolved according to the oxygen consumption rate (OCR). The evolving trend of cytotoxicity derived from OCRs was in agreement with cell viability obtained from 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Moreover, the direct damage of PDT on cell mitochondria was successfully detected by monitoring respiration instantly after PDT treatment, which is actually beyond the scope of MTT assay. These results suggest that fluorescence sensing of ic-O2-associated cell respiration is promising and even may become a standardized method, complementary to MTT assay, to evaluate PDT-induced cytotoxicity.

Elastic intramedullary nail for treatment of extremity fractures in children.

OBJECTIVE: To assess the clinical therapeutic effects of elastic intramedullary nail on extremity fractures in children. METHODS: From June 2005 to March 2008, 40 children with extremity fractures were treated by elastic intramedullary nail, in whom femoral shaft fractures occurred in 26 cases, tibiofibular fractures in 8 cases, radial capitular fractures in 4 cases, ulnoradial fractures in 2 cases. All patients were treated by closed reduction and elastic intramedullary nail fixation. RESULTS: All the fractures gained satisfactory reduction and healing. The average duration needed for fracture healing was 1-2 months. Postoperative follow-up confirmed a sound functional recovery. CONCLUSIONS: The elastic intramedullary nail is a minimally invasive and effective surgical approach for treatment of extremity fractures in children. It allows early functional exercises after operation and secures a satisfactory bone union and functional recovery.

Depletion potentials in colloidal mixtures of hard spheres and rods.

The depletion potential between a hard sphere and a planar hard wall, or two hard spheres, imposed by suspended rigid spherocylindrical rods is computed by the acceptance ratio method through the application of Monte Carlo simulation. The accurate results and ideal-gas approximation results of the depletion potential are determined with the acceptance ratio method in our simulations. For comparison, the depletion potentials are also studied by using both the density functional theory and Derjaguin approximations. The density profile as a function of positions and orientations of rods, used in the density functional theory, is calculated by Monte Carlo simulation. The potential obtained by the acceptance ratio method is in good agreement with that of density functional theory under the ideal-gas approximation. The comparison between our results and those of other theories suggests that the acceptance ratio method is the only efficient method used to compute the depletion potential induced by nonspherical colloids with the volume fraction beyond the ideal-gas approximation.

Density of states of a two-dimensional XY model from the Wang-Landau algorithm.

Using the Wang-Landau algorithm combined with the analytic method, the density of states of a two-dimensional XY model on square lattices of sizes 16x16, 24x24, and 32x32 is accurately calculated. Thermodynamic quantities, such as internal energy, free energy, entropy, and specific heat are obtained from the resulted density of states by numerical integration. It is found that both the density of states and the extensive thermodynamic quantities obey the scaling law. From the entropy curve, symptoms of phase transition are observed. A general method of calculation of the density of states of continuous models by simulation combined with analytical method is proposed.

Coupled exofixator for comminuted fracture of humeral shaft.

OBJECTIVE: To report and assess the efficacy of a coupled exofixator in the treatment of comminuted fracture of the humeral shaft. METHODS: From June 1999 to September 2003, 24 patients with comminuted fracture of the humeral shaft were treated in our department, in whom 11 were involved in left humerus fractures and 13 in right humerus fractures. Closed reduction or open reduction with a small incision as well as a coupled exofixator was used to treat these patients. RESULTS: All cases got anatomical reduction after 6-12 months follow-up. The time for fracture union averaged 5.8 months with a good functional recovery of the shoulder-elbow joints. CONCLUSIONS: The coupled exofixator is favorable to the treatment of comminuted humeral shaft fractures. It can shorten union time and avoid nonunion occurrence.