In this paper, a method for dose calculation with pencil beam kernels constructed by point kernel superposition was proposed to accelerate the dose calculation during intensity optimization iteration. With this method, the direct aperture optimization method can be integrated in the planning system based on point kernel convolution/superposition model. The dose calculation time was also reduced during the iteration. From the result of the phantom and clinical patient data test, it was concluded that this method could be used for the intensity optimization of iteration dose calculation as the satisfied precision due to the optimization result coherence obtained. By implementing the method in the planning system product based on point kernel convolution/superposition model, a lot of additional research and development works for the pencil beam dose calculation model as well as the product maintenance cost can be avoided.
Algorithms ; Humans ; Models, Theoretical ; Phantoms, Imaging ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; Software

Objective To review the prevalence of nosocomial infection and the change of drug resistance in a comprehensive intensive care unit (ICU) and to provide theoretical basis for clinical prevention and treatment.Methods The strains of bacteria and fungi were isolated from ICU and their drug resistance was retrospectively analyzed from Jan.1st,2010 to Dec.31th,2011.Results The main pathogen of nosocomial infection were Gram-negative bacteria ( 73.3％ ),Gram-positive bacteria ( 17.9％ ) and fungi ( 8.7％ ).In bacterial infection,Gram-negative and G-positive bacteria accounted for 80.3％ and 19.7％ respectively.In Gram-negative bacteria,pseudomonas aeruginosa was the major type (21.7％).In Gram-positive bacteria,staphylococcus aureus (31.4％) was most prominent.Drug resistance of bacteria was severe,while that of fungi was mild.Conclusion Bacteria has severe drug resistance and exhibits multi-drug resistance for commonly used antibiotics.The principle of antibiotics application should be mastered and antibiotics should be chosen according to drug-sensitivity tests.

Objective: To prepare ibuprofen dispersible tablet and compare its pharmacokinetics and bioavailability with market tablets in rabbits. Methods: According to inspection of factors and orthogonal design, optimal formulation was decided. A randomized crossover and self control design was used. Eight healthy rabbits were single oral dosed with 100 mg ibuprofen dispersible tablet or market tablet, respectively. The plasma drug concentration was determined by HPLC method. The pharmacokinetic parameters were calculated by 3P87 program and the bioequivalence was assessed by NDST5.0 program. Results: A one compartment open model was adopted and the pharmacokinetic parameters of dispersible tablet and market tablet were as follows: c max were (9.79?2.25) and (4.54?1.50) ?g/ml; t max were (0.27?0.07) and (2.03?0.53) h; t 1/2 were (6.65? 2.14) and (9.17?4.38) h; AUC 0~∞ were (94.11?28.38) and (65.20?18.38) ?g?h?ml -1 , respectively. Ralative bioavailability of the dispersible tablet was 164.11% compared to market tablet. Conclusion: Ibuprofen dispersible tablet is administrated easily and absorbed quickly, and its bioavailability is far more better than the market one. [

Objective: To prepare silibinin solid dispersion and measure its dissolution in vitro .Methods: Silibinin solid dispersions were obtained with urea, PVP and poloxamer188 as carriers by melting and coevaporation methods. Differential thermal analysis and powder X ray diffraction were used to determine the status of drug in carriers, and the dissolution characteristics in vitro were studied in simulated gastric juice. Results: In PVP silibinin solid dispersions drug was amorphous; in poloxamer188 silibinin solid dispersions, drug existed as fine crystal, while in urea silibinin solid dispersions most of silibinin existed as crystal, only a little as molecule. Poloxamer188 was the better carrier in improving the solution and dissolution rate of the drug. Conclusion: Poloxamer188 is a very useful carrier in improving the solubility and dissolution of silibinin. [

Objective To explore the expression of merlin and cyclins and the nucleocytoplasmic shuttling of merlin in abiogenous vestibular schwannoma tissues. Methods Four paraffin imbedding vestibular Schwannoma samples were included in the study.The cyclins and merlin were analyzed by immunofluorescence at the same time,and the expression and location were synchronously observed with confocal laser microscopy(CLM) in a single schwannoma cell. Results Cyclins and merlin were perspicuously and synchronously presented in a single cell in vestibular schwannoma tissues.In early G1 phase of the tumor cell,merlin was mainly stained in the nucleus,followed by perinucleus and cytoplasm.In G1/S phase,merlin was concentrated in the perinucleus,less in the nucleus and cytoplasm.Merlin staining showed uniform distribution in the nucleus in G2/M phase,while was absent from the nucleus and concentrated in the perinucleus in late G2/M phase. Conclusion The expression of merlin and various kinds of cyclins can be synchronously presented in abiogenous vestibular schwannoma cells with immunofluorescence and CLM.Merlin is shuttling among the nucleus,cytoplasm and perinucleus along with the progression of cell cycle.

Now the layer-by-layer self-assembling (LbL) technique has become an attention-getting reparative methodology for ultrathin film formation. Many scientists in different academic areas including bioengieering, medical science, drug controlled release, optoelectronics dive into this technology. Among of them, carriers with structures which can be flexibly controlled are more useful since functional structure units can be assembled in layer-by-layer fashion, which is simplicity, chemical mildness, concealment, can achieve targeted drug delivery and so on. In this review, we have discussed the advantage, development, influential factors and applications of LbL. We have focused on reviewing the applications and perspective of nanoparticles, microgels and capsules were both fabricated via the LbL assembling at drug delivery.

Objective To study the character of transformation of H.pylori into coccoid form under oxidative stress, and the changes in the biological charasteristics after transformation. Methods The coccoid form of H.pylori was studied with bacteriological, enymological, and genetical methods to identify its differences from the original form. Animal experiment was conducted to determine its implantation capacity. Results Morphological transformation from spiral to coccoid form occurred with the prolongation of culture under oxygen stress. The metabolic activity was reduced gradually, finally maintained at a lower level. The activities of urease, alkaline phosphatase and acid phosphatase were decreased markedly. The mRNA levels of main virulence factors were declined. Both mRNA and activities of enzyme of Sod B and Kat retained high levels. A part of the coccoid forms showed reversion to helical form, and colonization in mice stomach could be found after being inoculated to mice. Conclusions The metabolism and virulence of H.pylori were all lowered under oxidative stress, but a part of the coccoid form may be viable. Sod B and Kat may play an important role in the oxygen metabolism of H.pylori.

Objective:To investigate the in vivo absorption kinetics of caffeine at different intestine segments in rats.Methods: The rat intestine was cannulated for in situ recirculation.The absorption kinetics of caffeine,including the absorption segments of intestine,drug concentration and pH value,were investigated in all the rats under light anesthesia.Ultraviolet light spectrometry and high-performance liquid chromatography were used to determine the concentrations of phenol red and caffeine,respectively.Results: The absorption rate constants(Ka) of caffeine in the small intestine at the concentrations of 2.5,5,10 and 25 mg?L-1 were 0.252,0.247,0.304 and 0.232 h-1,respectively.The Ka values at pH of 7.8,6.8,and 5.4 were 0.267,0.274 and 0.247 h-1,respectively.The Ka values in the duodenum,jejunum,ileum,and colon were 0.112,0.099,0.095 and 0.069 5 h-1,respectively.Conclusion: Concentration and pH value have no obvious effect on the absorption kinetics of caffeine.Caffeine can be better absorbed in the duodenum,jejunum and ileum than in the colon.The absorption of caffeine in the intestine is a first-order process through passive diffusion mechanism.

Pulsed drug delivery(PDD),which can be released at well-defined time points as the therapy needs,can decrease the frequency and avoid taking drug at night,thus improving patient compliance.Here we introduce three kinds of programmed PDD systems independent of external chemical triggering;they are divided according to the triggering mechanisms:degradation-triggered PDD,osmotic pressure-triggered PDD,and both degradationi and osmotic pressure-triggered PDD.This paper reviews preparing technique,release mechanisms and influencing factors of the three PDD systems.The release profiles of pulsatile PDD can be regulated for different therapeutic needs,requiring no external triggers;especially that the PDD system triggered by both degradation and osmotic pressure has a bright future.

Objective To discuss the clinical effect of combination therapy under the theory of "treating soft tissue for bone disease" on knee osteoarthritis.Methods The 160 cases were randomly divided into control group(80 cases) and experimental group(80 cases).The control group was treated by diclofenac sodium sustained release capsules(per os) and sodium hyaluronate(intra-joint injection).The experimental group was treated by traction,steaming and washing,massage,needle-knife therapy,manipulation on soft tissues for loosening the joint,and orthepedic insoles.The course of treatment was 3 weeks.The effect was evaluated according to Lysholm Score,knee movement and subjective satisfaction after the follow-up for 6 months.Results Of the 154 cases completed the study(control group 75 cases and experimental group 79 cases),the Lysholm Score and knee movement had a very significant improvement(P