OBJECTIVE:To prepare Activated carbon N-acetylcysteine microcapsule (ACNAC),and to optimize preparation technology. METHODS:ACNAC was prepared by emulsion cross-linked method using biodegradable material gelatin as capsule wall material. Using comprehensive evaluation index of drug-loading amount,entrapment rate and particle size distribution percent-age(the percentage of 80-140 μm particle)as index,drug-loading ratio,amount of gelatin,mixing speed and the amount of emul-sifier as factors,single factor test and orthogonal test were used to optimize formulation technology. The technology was validated and distribution of particle size of ACNAC was determined. RESULTS:The optimal formulation technology was as follows as drug-loading ratio 1∶1,gelatin 15%,emulsifier 2.0%,mixing speed 1 000 r/min. Average drug-loading amount of 6 batches of ACNAC was 15.9%(RSD=1.21%),average encapsulation efficiency was 78.1%(RSD=1.11%)and average particle size distri-bution percentage was 81.9%. CONCLUSIONS:ACNAC is prepared successfully,and formulation technology is reasonable and feasible.

Objective To evaluate the clinical efficacy of staged treatment of complex tibial plateau fractures with temporary transarticular external fixation and delayed plate fixation.Methods Enrolled in this study were 44 cases of complex tibial plateau fracture who had been treated from January 2011 to January 2014.Temporary transarticular external fixation and delayed plate fixation was adopted in 22 patients (observation group),involving 14 men and 8 women with an average age of 45.5 ± 11.4 years,and 10 left sides and 12 right sides.By the Schatzker classification,13 cases were type Ⅴ and 9 type Ⅵ.Calcaneal traction and plate fixation was adopted in the other 22 patients (control group),involving 13 men and 9 women with an average age of 43.8 ± 10.4 years,and 8 left sides and 14 right sides.By the Schatzker classification,12 cases were type Ⅴ and l0 type Ⅵ.The 2 groups were evaluated by the time from hospitalization to plate fixation,operation time,intra-operative bleeding volume,hospitalization time,healing time,complications and Hospital for Special Surgery (HSS) scoring at the final follow-ups.The 2 groups were compatible with no significant differences regarding the preoperative general data (P ＞ 0.05).Results The 44 patients were followed up for 12 to 30 months (mean,18.6 months).There were significant differences between the 2 groups in the time from hospitalization to plate fixation,operation time,intra-operative bleeding volume and hospitalization time (P ＜ 0.05).There was also a significant difference in the complications rate (4.5％ (1/22) for the observation group versus 27.3％ (6/22) for the control group) (P ＜ 0.05),but there was no significant difference in the good to excellent rate by HSS scoring [86.3％ (19/22) versus 81.8％ (18/22)] (P ＞ 0.05).Conclusions Although both methods can treat complex tibial plateau fractures,temporary transarticular external fixation and delayed plate fixation may be preferable because it can lead to decreased hospitalization time,less intra-operative bleeding volume,fewer surgical complications and good functional recovery of the knee.

Objective To investigate the effect and safety of comprehensive therapy based on femoral head arthroplasty in treating old femoral neck fracture in the elderly complicated with other severe basic medical conditions.Methods Thirty-six elderly patients with old femoral neck fracture were treated with femoral head arthroplasty.Mean age of the patients was 78.2 years, and mean duration since injury was 13.7 months.All the patients had at least one severe basic medical problem.Perioperative complications were retrospectively analyzed, and function of hip joint was evaluated 6 months after operation.Results One patient died because of severe pulmonary infection, while 16 electrolyte imbalance, 7 hypotension, 4 arrhythmia, 2 acute heart failure and 1 acute kidney injury were cured in the rest 35 patients.Harris hip score of the 35 patients increased from (22.0 ± 6.8) points pre-operatively to (69.2 ± 10.8) points 6 months post-operatively (P ＜ 0.01).Conclusions Comprehensive therapy based on femoral head arthroplasty is effective for old femoral neck fracture in the elderly suffering severe underlying diseases.Early treatment, perfect pre-operative preparation, correct manipulation and appropriate perioperative management play important roles.

Objective:To design a semi-spherical applicator for delivery of semi-spherical dose distributions and assess its dosemetric characteristics.Methods:The applicator was designed in the following way. First, the scattering angle and dose rate of the electron beam having passed through a series of scattering foils of different thicknesses were calculated to determine the thickness of the scattering foil. And then, a series of location model was designed, and the variances of the mean electron energy on the surface of these models were calculated to determine the foil location. Finally, the relationship between the geometric characteristics of the layer and the surface dose on the applicator was established to design the modulator. Monte Carlo (MC) codes EGSnrc/BEAMnrc and EGS4/DOSXYZ were employed to model the head of the Mobetron, the location model, the layer, the semi-spherical applicator, and to calculate the dose distributions.Results:A semi-spherical applicator was designed for electron beam of energy 12 MeV, which consisted of a 2.5 cm diametre cylindrical collimator with 0.5 cm thick wall made of 0.3 cm thick steel and 0.2 cm thick water equivalent material (WEM), a 0.14 cm-thick foil made of tansgen, and a 2.5 cm diametre hollow semi-sphere containing a crescent modulator made of WEM. The dose rate was about 160 cGy/min, and the depth of the 50% isodose curve was 0.85 cm.Conclutions:We designed and performed a MC simulation of a semi-spherical applicator to deliver a semi-spherical dose distribution from a high energy electron beam.