[en] A soft x-ray polarimeter with multilayer was developed at the Beijing Synchrotron Radiation Facility (BSRF). The polarimeter was designed to utilize reflection and transmission geometry. Four operational modes have, been designed and carried out. Some experiments have been performed by using this polarimeter with various modes. The polarization properties of Mo/Si and Cr/C multilayer have been measured, the results of researches showed that the non-periodic and periodic multilayer can be used as polarizing elements in soft X-ray with synchrotron radiation. Using the home-made synchrotron radiation soft X-ray polarimeter and multilayer elements, the polarization characteristics of the Beamline 3WIB have been measured systemically at BSRF. The degree of linear polarization is up to 0.995 from 0.585 at 206 eV when the beam is polarized by multilayer optical elements. We also measured magneto-optical Faraday rotation around the M_2_,_3 edges (60-70 eV) of Ni film on Beamline 3WIB. The results demonstrate that the Faraday rotation angles are obviously large around Ni M_2_,_3 edges, the rotation angles are 1.85±0.19° and-0.75±0.09° at the energy 65.5 eV and 68 eV, respectively. (authors)

[en] Bacillus amyloliquefaciens ES-2 was implanted with 20 keV N⁺ ion beam to breed mutants of high yield of antimicrobial lipopeptides. The dose effects of the nitrogen ion implantation on the survival and positive mutations rate was studied. The mutant strain designated as B. amyloliquefaciens ES-2-4 showing higher yield of antimicrobial lipopeptides was obtained. The concentration of the lipopeptides in fermentation liquid increased by 15.2% compared with the original strain. The authors also studied the fermentation process between the mutant and the original strain. It indicated that the mutant with shorter lag phase, longer stable phase and higher yield of the lipopeptides, which was suitable for large-scale production. (authors)

[en] Objective: To investigate the relationships of X-ray tube voltage (kVp) with surface dose of the phantom and phantom-thickness on the basis of the particular signal to noise ratio of X-ray images. Methods X-ray digital subtraction angiography was simulated using a phantom made of acrylic acids. Under the particular surface dose of X-ray image intensifier, the curve of the surface doses of phantom surface-kVp and the curve of the phantom thickness-kVp were acquired with different exposure combinations of kVp and mAs. Results: According to the curve of the surface dose of phantom-kVp, it suggestsd that the gradual increase in kVp corresponded to the gradually decreased surface dose of phantom, with the slope tending to zero. However, the gradual increased phantom thickness corresponded to the gradually increased kVp on the basis of the curve of the phantom thickness-kVp, with the presentation of kVp = 64 + 0.89D (phantom thickness, cm) between the phantom thickness and kVp. Conclusion: The graduall increased in kVp might result in the gradual decrease in surface dose of phantom, the optimized kVp relating directly to the phantom thickness. (authors)

[en] Objective: To evaluate the 3-dimention (3D)CTA, MRA and DSA imagings in the application of dense packing for curing aneurysm. Methods: 64 patients with intra-cranial aneurysms were treated with clipping or endovascular techniques (including 72 aneurysms with 60 intravascular embolizations). Their 3D images were studied, the characteristics of CTA MRA and DSA were compared. Results: Among 72 aneurysms, 60 were packed with dense packing in 50 patients, >95% packing in 10 cases. The measurement of aneurysm in 3D-CTA showed bigger than that of 2D-DSA; and that of 3D-DSA was bigger than that of 2D- DSA. Conclusion: Aneurysms could be obliterated by endovascular technique; dense packing in 3D images would be achieved in most patients, but the 3D images showed aneurysm often larger than those of 2D images. (authors)

[en] Objective: To discuss the clinical value of MR diffusion-weighted imaging (DWI) in the follow-up of hepatocellular carcinoma after transcatheter arterial chemo embolization (TACE). Methods: MR DWI was performed in 16 patients with hepatocellular carcinoma after receiving TACE. The DWI findings were compared with DSA and/or CT signs. The mean apparent diffusion coefficient (ADC) value of each lesion was determined separately, and the mean ADC value of intra-hepatic metastatic lesion was compared with that of the primary lesion. Results: A total of 18 lesions were revealed in DSA, of which satisfactory iodinated oil deposit was seen in 11 (satisfactory group) and poor deposit in 7 (poor group). After TACE, the mean ADC value of normal hepatic parenchyma showed no obvious changes when compared to its preoperative value (t = 0.54, P > 0.05). The mean ADC value obtained in poor group was significantly lower than that obtained in satisfactory group (t = 4.81, P < 0.01). In satisfactory group the preoperative ADC values were higher than the postoperative ones (t = 6.81, P < 0.01), while in poor group no significant difference was found between preoperative and postoperative ADC values. In addition, twelve intra-hepatic metastases were detected on DWI. Statistically significant difference in the mean ADC value existed between the metastatic lesions and the primary lesions (t = 4.61, P < 0.01). Conclusion: DWI is very sensitive in detecting hepatic metastatic lesions and, therefore, can be used to evaluate the therapeutic effect of TACE. (authors)

[en] Objective: To analyze the diffusion-weighted MR imaging findings in ischemic spinal cord lesions and discuss the value of diffusion-weighted MR imaging in differentiating diagnosis with inflammatory diseases and tumors. Methods: Six patients (2 male, 4 female) with typical sudden onset of neurological deficits caused by spinal cord ischemia were evaluated. There were no definite etiologies in all patients. DW imaging was performed within 1 to 30 days after the initial neurological symptoms using a Philips Gyroscan 1.5 TMR system. Four patients had other scans including contrast-enhanced MR imaging (CE-MRI) and/or FLAIR scans. Two of them followed up with MR images in three months. All six patients were imaged using a multi-shot, navigator-corrected, echo-planar pulse sequence, and ADC values were calculated in sagittal-oriented plane. Results: MR abnormalities were demonstrated on sagittal T₂-weighted images with 'patch-like' or 'strip-like' hyperintensities (6/6) and cord enlargement (5/6). Axial T₂-weighted images showed bilateral (6/6) hyperintensities. In one patient only the posterior spinal artery (PSA) territory was involved. Spinal cord was mainly affected at the cervical (2/6) and thoracolumbar (4/6) region, two of them included the conus medullaris (T10-L1). DW images showed high signals in all infarct lesions, degree of intensity depended on scanning time from ill-onset and progress of illness and whether companied with hemorrhage. In this group, except one case with closely normal ADC value due to one month course of illness, the five others ADC values of lesions calculated from ADC maps arranged from 0.23 x 10^-3 mm²/s to 0.47 x 10^-3 mm²/s [average value (0.37 ± 0.10) x 10^-3 mm²/s], markedly lower than normal parts [ average value (0.89 ± 0.08) x 10^-3 mm²/s]. There were marked difference between lesions and normal regions (t=4.71, P<0.01). Five cases had better contrast of signals in DW images than in T₂W images. Meanwhile, lesions could be displayed much better in DW images than in T₂W images because of CSF presenting low signals in DW images. Dynamic or repeated DWI examinations would be helpful for analyzing the degree of injury and recovery. Most lesions showed non-enhanced effects in CE-MRI except one lesion showed irregular slight enhancement. Conclusion: MR imaging is useful in detecting spinal cord infarction. DW imaging of the spinal cord may provide additional information for assessment of ischemic changes and help improve ability in differentiating diagnosis. (authors)

[en] Preoperative portal vein embolization (PVE) has become an important tool in the management of selected patients with hepatic cancer before the major hepatic resection is carried out. PVE can redirect the portal flow to the intended future remnant liver tissue in order to induce the hypertrophy of the non-diseased portion of the liver and thereby may reduce the occurrence of complications and shorten the hospitalization days after surgery. This article aims to review the technical and clinical considerations in performing PVE and to discuss the PVE-related practical points, including the relevant anatomy, the access approach,the choosing of embolic agents and the pathophysiology of PVE. In addition, the indications and contraindications for performing PVE, the use of combination therapies and the concern for tumor growth after PVE are also discussed. (authors)

[en] Objective: To compare the mechanical characteristics of blood clot models used for the evaluation of interventional thrombectomy devices for acute stroke, and to provide more scientific blood clot models for the manufacture of interventional thrombectomy devices. Methods: The Kan's and Gralla's radioparent tube clots model was duplicated. The spontaneous radioparent tube red clots (SNTR) and spontaneous radioparent tube of white clots (SNTW) were prepared. By bending testing and elongation testing the mechanical properties of clot models were evaluated. By using HE staining the organizational structure of the clot models was assessed. Software SAS9.3 was used to analyze the data. Results: SNSW (Kan model), TNTR (Gralla model), SNTR and SNTW were successfully prepared. The bending testing of the four radioparent clot models that carried quite different mechanical properties was separately performed at 24 hours, one and two weeks later. The results showed that the elasticity of SNSW was (5.00 ± 4.47), (4.16 ± 3.76) and (5.83 ± 6.64) degree respectively; the elasticity of TNTR was (19.33 ± 6.05), (16.66 ± 4.08) and (19.16 ± 9.70) degree respectively; the elasticity of SNTR was (10.00 ± 7.07), (7.50 ± 6.89) and (13.33 ± 4.08) degree respectively; and the elasticity of SNTW was (87.5 ± 2.73), (81.66 ± 6.83) and (88.33 ± 4.08) degree respectively. The elongation testing of the four radioparent clot models that carried quite different mechanical properties was separately performed at 24 hours, one and two weeks later. The results showed that the stretch limit of SNSW was (4.43 ± 0.38), (4.67 ± 0.29) and (4.60 ± 0.31) cm respectively; the stretch limit of TNTR was (3.79 ± 0.13), (3.91 ± 0.11) and (3.91 ± 0.16) cm respectively; the stretch limit of SNTR was (3.25 ± 0.15), (3.46 ± 0.10) and (3.33 ± 0.27) cm respectively; the stretch limit of SNTW was (4.22 ± 0.18), (4.40 ± 0.32) and (4.11 ± 0.15) cm respectively. Conclusion: SNSW, TNTR SNTR and SNTW are four clot models with different mechanical properties. It is reasonable that the use of one proper clot model or some of these clot models should be based on the purpose of the study. (authors)

[en] Objective: To evaluate the effect of intramyocardial administration of basic fibroblast growth factor on angiogenesis of infarcted myocardium in dogs. Methods: Twenty-four mongrel dogs were randomized into control group and therapeutic group. Acute myocardial infarction was made by ligation of the left anterior descending coronary artery distal to its first diagonal branch. As soon as coronary artery was occluded, 50 mg of basic fibroblast growth factor in 15 ml of saline was injected into the infarcted and border zone in therapeutic group, whereas 15 ml saline alone was used in the same way in control dogs. Every 3 dogs in each group was studied on the 1^st day, the 3^rd day, the 10^th day, and the 17^th day, respectively. Electron microscope was used to observe the growth of capillaries. Angiogenesis was evaluated by immunohistochemical studies with VIII factor. With sensitivity encoded technique, cine MR and MR perfusion imaging were performed on each dog within 3 hours after surgery and before euthanasia to evaluate cardiac function and the characteristics of myocardial perfusion. Results: In therapeutic group, LVEF improved markedly since the 10^th day (on the 10^th day: control group 24.09 ± 3.32, therapeutic group 45.71 ± 6.27; on the 17^th day: control group 31.46 ± 4.60, therapeutic group 53.46 ± 5.24). Hypoenhancement on first pass and hyperenhancement on delayed phase appeared in infarcted myocardium. There were significant differences for the time of upslope, peak time of signal intensity, upslope curves ratio, and contrast enhancement ratio between infarcted and normal myocardium. The size of infarcted myocardium was markedly decreased on the 17^th day [control group (9.04 ± 1.59)%, therapeutic group (4.07 ± 1.20)%]. The capillaries grew actively in therapeutic group and microvessel density was higher in therapeutic group than in control group except the first day (control group and therapeutic group respectively on the 3^rd day: 92.3 ± 11.6, 147.3 ± 11.6; on the 10^th day: 125.0 ± 12.1, 182.7 ± 14.0; on the 17^th day: 124.7 ± 14.5, 223.7 ± 19.9). Conclusion: Intramyocardial administration of basic fibroblast growth factor is useful in increasing the growth of microvessels, decreasing the size of the infarcted myocardium, and improving left ventricular function in acute myocardial infarction

[en] Objective: To evaluate DSA-guided embolization in establishing different spinal cord ischemia models of canine and relevant diffusion-weighted imaging (DWI) application. Methods: Nine canines were randomly divided into three groups with different matching of lipiodol and diatrizoate meglumine which were injected into bilateral intercostal arteries at 9-11 level guided by DSA monitor. Then observe the changes of motor function and pathologic findings, especially perform routine MRI and DWI by a 1.5 T MR system. Results: Except one case, 8 embolization models were established successfully. Among three groups, slight-group got slight injury and muscle power was about 3-5 grade and range of injury was about two vertebra distance; medium-group presented obvious paraplegia and muscle power was 0-1 grade and range of injury was between 3-4 vertebra distance; severe-group showed greater severity and larger range of injury. All lesions presented high signals at routine MRI and DWI. Conclusion: Using different matching of lipiodol and diatrizoate meglumine can establish different spinal cord ischemia models of canine by DSA- guided embolization and DWI can be performed successfully by 1.5 T MR system, which may be a good method for advanced study of spinal cord ischemia. (authors)