How to use clustering techniques in PACS system is introduced. Two kinds of cluster solution to configure PACS system is proposed.
Computer Systems ; Radiology Information Systems ; organization & administration

According to the related standards, an in vitro corrosion fatigue testing of coronary stents was designed. The stents were fixed in the latex tubes, which were full of 0.9% saline solution, and radial stress was produced for simulating natural vessel. The accelerated fatigue test was performed with 4 x 10(8) cycles at a frequency of 60 Hz, which was equal to 10 years in vivo implantation. Twelve coronary stents made from stainless steel were adopted in the experiment. The bulk structure and surface morphology before and after testing were analysed by scanning electron microscopy. The structure damage and surface change caused by corrosion fatigue were identified and the probable reasons were proposed.
Biocompatible Materials ; chemistry ; Computer Simulation ; Corrosion ; Equipment Failure Analysis ; Humans ; Materials Testing ; Models, Cardiovascular ; Stainless Steel ; chemistry ; Stents ; Time Factors

OBJECTIVE To study the effect and mechanism of N1,N2 bis(2,3-dihydroxy-4,6-disul-fonic acid benzyl)ethylenediamine sodium salt(NBED)on uranium excretion.METHODS ICR mice were divided into the blank control group,uranium exposure group(0.03 mg·mouse-1),uranium expo-sure+diethylenetriamine pentaacetic acid(DTPA-CaNa3)(150 mg·kg-1)group,and the uranium expo-sure+NBED(45,90,180 mg·kg-1)group.After uranyl acetate was injected into the tail vein of mice,appro-priate doses of NBED or DTPA-CaNa3 were injected into the tail vein.After 24 h,the uranium contents in the kidney,bone and liver+spleen+muscle were determined by inductively coupled plasma mass spectrometry(ICP-MS).The dissociation constant of NBED and the complexation constant of NBED with uranyl were determined via potentiometric titration.RESULTS Animal experiments showed that NBED 45,90 and 180 mg·kg-1 could significantly reduce the uranium accumulation in the kidney by 48.2%-66.5%,in the bone by 21.4%-54.8%,and in liver+spleen+muscle by 38.2%(P<0.01),compared to the uranium exposure group,47.8%,21.4%and 22.7%respectively by DTPA-CaNa3(P<0.05),and the effect in the NBED 180 mg·kg-1 group was significantly better than in the DTPA-CaNa3 group(P<0.05).The results of potentiometric titration showed that there was about 22.3%LH5,59.8%LH4 and 17.85%LH3(L means NBED)in NBED at pH 7.4,and the secondary dissociation LH4 was the main form.In the range of pH 3-11,there were four complex compounds of NBED and uranyl,and their step-wise complex cumulative constants were logβ111(12.5),logβ101(9.8),logβ102(15.3),logβ1-12(6.5)respectively.The(UO2)L22-was the main species(75.3%)at physiological pH 7.4,and the-log[UO22+free]value(pUO2)of free uranyl ion in solution was 9.57.CONCLUSION NBED mainly exists in the form of secondary dissociated LH4in vivo,and chelates with uranyl 2:1 to form uranyl complex,which is excreted in vitro.Intravenous administration of NBED can more effectively promote excretion than DTPA-CaNa3.