XPS分析过程中X-射线照射对PET的影响

利用X-射线光电子能谱仪的X-射线源照射PET薄膜样品,通过XPS方法原位分析表征了X-射线照射对PET样品的损伤影响。X-射线照射对PET样品的影响显著:随着X-射线照射时间的延长,C1s峰整体向低结合能端发生位移,PET样品中元素C和O的原子百分含量分别呈线性升高和线性下降的趋势,官能团C—O和O=C—O的数量呈线性减小趋势。X-射线照射热效应导致的PET热降解是造成这些变化的主要原因。

Selected Major Elements Content in Igneous Rocks of Paraguay by Neutron and X-ray Irradiation

Plutonic and volcanic rocks were analyzed by INAA （Instrumental Neutron Activation Analysis） ana XRF （X-ray flurescence） in their major components for its classification. The samples proceed from the sites/regions corresponding to the Precambrian to Paleozoic/Postpaleozoic magmatism in the eastern and western Paraguay. The analysed elements were Si, A1, Na and K and thus the SiO2, AI/O3, Na2O and K2O content determined. The activation were performed in an annular 25Ci Am-Be neutron source with total flux of 5×10^7n.s^-1. The reactions used were （1） ^28Si （n, p） ^27A1, （2） ^27A1 （n, p） ^27Mg; （3） ^23Na （n, γ） ^24Na, the fourth element of interest, potassium, was analysed by XRF. The procedure overall uncertainties were checked as per the analysis of three compositae samples of SiO2： ＋ A12O3 ＋ NaHCO3 ＋ K2CO3 prepared as standards in convenient proportions. The determination of these parameters according to the last recommendations of the IUGS （International Union of Geosciences）, permits the classification of the rocks in the categories acid, intermediate, basic and ultrabasie, as well as the identification of the rock family and in certain cases, the norm and their magmatic provenance.

Radiobiological effect of abdominal X-ray hypo-fraction irradiation on Wistar rats liver

Objective: The aim of our study was to investigate the impact of abdominal hypo-fraction irradiation on liver damage in rats so as to provide a reference for its clinical application. Methods: A total of 100 Wistar rats were equally randomized to five groups as control, 4 Gy, 6 Gy, 8 Gy and 12 Gy group, and the corresponding fractionated doses were offered. Liver functions were examined at the 2nd, 4th, 6th, 8th and 10th week after irradiation. Morphological changes were observed by HE staining. Expressions of Bcl-2 and Bax were examined by immunohistochemical technique. Results: In all irradiation groups, hepatocellular swell, degeneration, necrosis and even hepatic fibrosis could be seen. The differences of the liver coefficient, Glutamyl pyruvic transaminase (GPT), Glutamyl oxaloacetic transaminase (GOT) were significant among the groups and different time points (F = 11.833-781.972, F = 20.857-264.692, P < 0.001). Expressions of Bcl-2 and Bax were significantly different between each group (F = 211.607, 116.577; P < 0. 001), and between each time point (F = 54.083, 68.749; P < 0. 001). Conclusion: Compare with conventional fraction, abdominal hypo-fraction irradiation may cause radiation damage to rat liver, being dose-and-time dependent. Up-regulation of activating apoptosis protein Bax and down-regulation of inhibiting apoptosis protein Bcl-2 may involve in the process.

香菇多糖对放化疗致动物白细胞减少症的影响

目的研究香菇多糖对放化疗致动物白细胞减少症的影响。方法通过制备小鼠和家兔白细胞减少实验动物模型,观察香菇多糖的升白作用。结果在所选择的剂量范围内,10、5、1 mg.kg-1剂量的香菇多糖不仅可以提升X射线照射和环磷酰胺致小鼠的外周血白细胞总数、血小板数量、血红蛋白含量和骨髓有核细胞总数,还可使外周血及骨髓白细胞分类趋于正常,减轻X射线照射和环磷酰胺注射所造成的骨髓抑制作用,并使胸腺、脾脏指数升高;3.7、1.9、0.9 mg.kg-1剂量香菇多糖可以提升盐酸阿糖胞苷致家兔的外周血白细胞、血小板数量和血红蛋白含量,并使外周血及骨髓白细胞分类趋于正常,减轻盐酸阿糖胞苷所造成的骨髓抑制,并使胸腺、脾脏指数升高。结论香菇多糖可以促进白细胞升高,减轻X射线照射、环磷酰胺、盐酸阿糖胞苷导致的骨髓抑制,明显改善骨髓的造血功能。

Role of 18F-fluorodeoxyglucose positron emission tomography imaging in surgery for pancreatic cancer

AIM： To evaluate the role of positron emission tomography using 18F-fluorodeoxyglucose （FDG-PET） in the surgical management of patients with pancreatic cancer, including the diagnosis, staging, and selection of patients for the subsequent surgical treatment. METHODS： This study involved 53 patients with proven primary pancreatic cancer. The sensitivity of diagnosing the primary cancer was examined for FDG-PET CT, cytological examination of the bile or pancreatic juice, and the serum levels of carcinoembrionic antigens （CEA） and carbohydrate antigen 19-9 （CA29-9）. Next, the accuracy of staging was compared between FDG-PET and CT. Finally, FDG-PET was analyzed semiquantitatively using the standard uptake value （SUV）. The impact of the SUV on patient management was evaluated by examining the correlations between the SUV and the histological findings of cancer. RESULTS： The sensitivity of FDG-PET, CT, cytological examination of the bile or pancreatic juice, and the serum levels of CEA and CA19-9 were 92.5%, 88.7%, 46.4%, 37.7% and 69.8%, respectively. In staging, FDG-PET was superior to CT only in diagnosing distant disease （bone metastasis）. For local staging, the sensitivity of CT was better than that of FDG-PEr. The SUV did not correlate with the pTNM stage, grades, invasions to the vessels and nerve, or with the size of the tumor. However, there was a statistically significant difference （4.6 ± 2.9 vs 7.8 ± 4.5, P = 0.024） in the SUV between patients with respectable and unresectable disease. CONCLUSION： FDG-PET is thus considered to be useful in the diagnosis of pancreatic cancer. However, regarding the staging of the disease, FDG-PET is not considered to be a sufficiently accurate diagnostic modality. Although the SUV does not correlate with the patho-histological prognostic factors, it may be useful in selecting patients who should undergo subsequent surgical treatment.

Highly metabolic thrombus of the portal vein:^(18)F fluorodeoxyglucose positron emission tomography/computer tomography demonstration and clinical significance in hepatocellular carcinoma

AIM： To assess the ability of ^18F-fluorodeoxyglucose positron emission tomography/computer tomography （^18F-FDG PET/CT） to differentiate between benign and malignant portal vein thrombosis in hepatocellular carcinoma （HCC） patients.METHODS： Five consecutive patients who had HBV cirrhosis, biopsy-proven HCC, and thrombosis of the main portal vein and/or left/right portal vein on ultrasound （US）, computer tomography （CT） or magnetic resonance imaging （MRI） were studied with ^18F-FDG PET/CT. The presence or absence of a highly metabolic thrombus on ^18F-FDG PET/CT was considered diagnostic for malignant or benign portal vein thrombosis, respectively. All patients were followed-up monthly with US, CT or MRI. Shrinkage of the thrombus or recanalization of the vessels on US, CT or MRI during follow-up was considered to be definitive evidence of the benign nature of the thrombosis, whereas enlargement of the thrombus, disruption of the vessel wall, and parenchymal infiltration over follow-up were considered to be consistent with malignancy. ^18SF-FDG PET/CT, and US, CT or MRI results were compared.RESULTS： Follow-up （1 to 10 mo） showed signs of malignant thrombosis in 4 of the 5 patients. US, CT or MRI produced a true-positive result for malignancy in 4 of the patients, and a false-positive result in 1. ^18F-FDG PET/CT showed a highly metabolic thrombus in 4 of the 5 patients. ^18F-FDG PET/CT achieved a true-positive result in all 4 of these patients, and a true-negative result in the other patient. No false-positive result was observed using ^18F-FDG PET/CT.CONCLUSION： ^18F-FDG PET/CT may be helpful in discriminating between benign and malignant portal vein thrombi. Patients may benefit from ^18F-FDG PET/CT when portal vein thrombi can not be diagnosed exactly by US, CT or MRI.

MRI and PET images fusion based on human retina model

The diagnostic potential of brain positron emission tomography （PET） imaging is limited by low spatial resolution. For solving this problem we propose a technique for the fusion of PET and MRI images. This fusion is a trade-off between the spectral information extracted from PET images and the spatial information extracted from high spatial resolution MRI. The proposed method can control this trade-off. To achieve this goal, it is necessary to build a multiscale fusion model, based on the retinal cell photoreceptors model. This paper introduces general prospects of this model, and its application in multispectral medical image fusion. Results showed that the proposed method preserves more spectral features with less spatial distortion. Comparing with hue-intensity-saturation （HIS）, discrete wavelet transform （DWT）, wavelet-based sharpening and wavelet-a trous transform methods, the best spectral and spatial quality is only achieved simultaneously with the proposed feature-based data fusion method. This method does not require resampling images, which is an advantage over the other methods, and can perform in any aspect ratio between the pixels of MRI and PET images.

Initial Approach to the Cellular Irradiation Injury of Human Pancreatic Carcinoma Cell Line MIA PaCa-2 by High Dose per Fraction

OBJECTIVE To investigate an initial approach of radiotherapy, which produces cellular radiation injury by high dose in one fraction. METHODS Human pancreatic carcinoma cell line MIA PaCa-2, was cultivated and divided into 5 groups： 0, 2, 5, 10, 17 Gy. Cultivated cells were irradiated by 6MV-X ray in one fraction. Analysis were done as follows： comet assay, which assessed the level of DNA damage in the treated cells right after the cell was irradiated, flow cytometry, which was performed at 0, 6, 12, 24, 36 h after the cell line treated to ladder, which quantitatively asses changes of its cell cycle, DNA assessed the degree of DNA injury after 6 and 12 h, and histological examination, which analyzed cellular morphology after 24 h. RESULTS （1） After X-ray irradiated, the morphological change of human pancreatic carcinoma cell line （MIA PaCa-2） was mainly swelling. （2） When the dose of radiation was lower than 10 Gy, increasing the dose could greatly improve cell necrosis, apoptosis and blockage of cell cycle in GJM phase, which was consistent with the theory of radiation biology. （3） When radiation dose was more than the 10 Gy, the peak of apoptotic necrosis appeared strong and early. （4） The degree of DNA injury was also related to the dose of radiation therapy and most obvious in the 10 Gy group and not so obvious in the 17 Gy group. （5） When dose was less than 10 Gy, DNA ladder was a single electrophoretic band; in the 10 Gy group, the electrophoresis showed a multiple ladder band; when dose was more than 10 Gy, a vague and irregular band appeared on the electrophoresis. CONCLUSION Oncotic necrosis may be the main cell death style when dose per fraction is high, which differs from conventional dose fraction radiation therapy.

Expression of Mitochondrial Transcripts in Gastric MGC803 Cell Line Subjected by Hypoxia

OBJECTIVE To determine the transcriptional expression of mitochondrial genome （mtDNA） in MGC803 cell lines subjected by various time-phase hypoxic dispositions, and further to discuss the influence of mtDNA transcripts on hypoxic resistance to irradiation. METHODS The MGC803 cells exposed to anoxic environment were divided into control group （0 h）, hypoxic group （2 h, 8 h, 16 h, 24 h） and irradiated group after exposing the hypoxia. RTPCR was applied to detect the transcripts of cytochrome oxidase subunit Ⅰ （COI）, NADH dehydrogenase subunit 4 （ND4）, ND5, cytochrome b （cyt-b） and ATPase6 （ATP-6） in MGC803 cell lines at various time-phases of hypoxic, and after X-ray irradiation. Flow cytometry and colony formation assay were conducted to evaluate the cell cycle phase and survival fraction. RESULTS COI and ND4 transcripts of MGC803 cell lines were influenced remarkably by hypoxia. COI transcripts were decreased remarkably with the elongation time of exposing the hypoxic, and reduced to one fourth of its original amount of prehypoxia 24 h after exposing the hypoxia. ND4 transcripts were increased initially, and elevated to two folds 8 h after exposing the hypoxia, and then reduced to one second 24 h after exposing the hypoxia. Hypoxia resulted in G1 phase blockage, especially after hypoxia for 16 h. The survival fraction of MGCS03 ceils exposing the hypoxia in irradiated group showed that as the time of exposing the hypoxic before irradiation is prolonged, the survival fraction of MGC803 cells may have an elevated tendency. CONCLUSION The tumor cells with lower expression levels of the COI and the ND4 after exposing the hypoxic have stronger resistance to the radiation, which indicates that increasing the expression levels of the COI and the ND4 might be advantageous to enhance the sensitivity of hypoxic tumor cells to the radiotherapy.

BODY SURFACE EXPOSURE DISTRIBUTION OF EXAMINEES RECEIVED UPPER G．I．T．X－RAY EXAMINATION

A special cloth for keeping LiF(Mg,Cu,P)TL dosimetry elements is worn by examinees. The exposures of 128 examinees .received upper G.I.T (gastro-intestinal tram) X-ray examination are measured. The reference point of the maximum body surface exposure given is at the middle of stomach. The average of this point is (4.97±1.94) × 10-4C.kg-1 person-1 examination-1 and (1.33±0.28)×10-4C.kg-1.min-1.

PET for Staging of Esophageal Cancer

FDG-PET is of clinical value especially for detection of distant metastases or recurrent esophageal cancer. For the staging of primary tumor or locoregional lymph node metastasis PET is cur- rently not suitable.

Characterization of nano-Ag/PVP composites synthesized via ultra-violet irradiation

Nano-silver/polyvinylpyrrolidone(PVP)composite materials were successfully synthesized bi-insitu from silver nitrate solution with N-vinyl pyrrolidone (NVP) monomer,containing neither initiator nor reductant, in ultraviolet irradiation conditions.The resultant Ag/PVP nanocomposites were characterized by infrared spectroscopy (FT-IR), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD).TEM show that nano silver particles are homogeneously dispersed in PVP polymer matrix, and the mean size of spherical silver particles is about 5 nm.The spectroscopy of XPS and FTIR showed that there is an interaction between nano silver not only with carbonyl oxygen but also with the nitrogen group within the NVP molecule through the p-π conjugation effect in the nano-silver/PVP composites system.

L3-Edge Jump and Shift on White-Line of Pd Interlayer for Trilaminar Neutron Production Target under H2^＋ Irradiation

Interlayer Pd for the Li/Pd/Cu neutron target for BNCT （boron neutron capture therapy） was characterized after 0.1-5 keV H2^＋ irradiation by XAFS （X-ray absorption fine structure） technique, and following conclusions were derived： （1） from the XAFS observation of white line of Pd, remarkable Pd L3 edge jump was found in 1.1-3 times higher than before irradiation in low irradiation fluence; （2） this fact indicates increase of hole density in Pd 4d-band, whereas, no change was observed for XASF spectra of Ag sample under the same irradiation conditions; （3） remarkable Pd L3 edge shift of 0.12-0.66 eV was also found with increase of H2＋ irradiation energy in low fluence, and drastically decreased after peak in high irradiation energy and fluence; （4） implanted protons deposited in Pd as negative under the balance of electron population enhanced by proton irradiation and charge transfer.

Role of VEGF-A/C and CCR-7 in the enhanced metastasis of A549 cells induced by 2 and 4 Gy X-rays in vitro and in vivo

Radiotherapy is a common strategy in treating lung cancer.Accumulating evidence suggested that radiotherapy has the potential to promote the metastasis and invasion of carcinoma cells.In this study,we aimed to testify the role of vascular endothelial growth factor(VEGF)and C-C chemokine receptor-7(CCR-7)in the metastasis of human adenocarcinoma A549 cells in vivo and in vitro.Nude mice were injected with A549 cells irradiated by 0,2 and 4 Gy X-rays,respectively.Quantitative detections of VEGF-A/C and CCR-7 mRNA from lung sample were performed by real-time RT-PCR.Small interfering RNA(siRNA)transfection technology was further used to testify the role of the genes in the metastasis of A549 cells.VEGF and CCR-7mRNA could only be detected 10 weeks post injection in vivo when visible tumor foci scattered in lung.In addition,VEGF-A/C mRNA expressed significantly higher in mice injected with A549 cells irradiated by 2 and 4 X-rays than those with 0 Gy X-rays irradiation.On the other hand,A549 cells with or without X-rays irradiation transfected with VEGF siRAN and CCR-7 siRNA showed a dramatic decrease of invasiveness compared to normal A549 cells with or without irradiation.The migration indexes were?0.7,?0.48,?0.34 and?0.32 for A549 cells with CCR-7 siRNA,VEGF siRNA,X-rays combined CCR-7 siRNA and X-rays combined VEGF-siRNA respectively.These results demonstrated that X-rays could promote the metastasis of A549 cells,and VEGF-A/C and CCR-7 mRNA were closely related to the metastasis of A549 cells in vivo and in vitro.

The impact of X-rays on the expressions of miR-130a/miR-25 and its potential role in the enhanced metastasis of A549 cell lines in vitro induced by X-rays

We aimed to investigate the impact of X-rays on miR-130a and miR-25 expressions of A549 cell lines and to understand the mechanism of miR-130a and miR-25 on the regulation of invasion and metastasis of A549 cell lines. Human adenocarcinoma cells of the line A549 were cultured and radiated by X-rays at the absorbed doses of 2 and 4, respectively by linear accelerator. Transwell invasion and migration assay were employed to exam the metastasis ability of A549 cells post X-rays irradiation. Both the miRNA and mRNA were extracted from A549 cells at different time points post radiation. The expressions of miR-130a and miR-25, as well as the expressions of VEGF and CCR-7 mRNAs, were detected in A549 cells with 2 and 4 Gy X-rays radiation, respectively by real time PCR. Results were statistically analyzed by SAS 8.2 software, which showed that the invasiveness of A549 cells post 2 and 4 Gy X-rays increased significantly compared with that of untreated A549 cells (the migration cell numbers are 20, 48 and 62 in Group 0, 2 and 4 Gy X-rays, respectively). Furthermore, the expressions of miR-130a and miR-25 also increased significantly at the time-points of 1, 2, 4, and 8 h post radiation, and began to decrease to the control level at 12 h post radiation. VEGF and CCR-7 mRNAs were detected to be up-regulated 18 h post radiation and remained at a high level till 72 h post radiation. The expression of VEGF mRNA has a close correlation with that of CCR-7 mRNA, and the expression of miR-130a also has a correlation with that of VEGF and CCR-7mRNAs. It is concluded that the metastasis of A549 cells in vitro could be promoted by X-rays, and miR-130a might play a role in the metastasis of A549 cells via regulating the expressions of VEGF and CCR-7 mRNAs.

Impact of TID on response to pulsed X-ray irradiation in the bipolar operational amplifier

Groups of a typical operational amplifier-μA741 were irradiated in a cobalt unit, each group accumulating a different total ionizing dose （TID）. The results showed that the TID caused power consumption current and slew rate （SR） to degenerate in ultra-linearity, owing to a severe reduction in the current gain of the internal LPNP transistors. Pulsed X-ray irradiation experiments were carried out on the μA741 groups with different values, and the results revealed that the impact on the response to the pulsed X-ray irradiation was greater when the devices absorbed more TID. The mechanism for this is explained on the basis of the circuit construction of the μA741; the sensitive parameters of the circuit were obtained via simulation on SP1CE. The simulation results additionally showed that if the sensitive parameters were optimized, the duration of interruption caused by the pulsed X-ray irradiation would be reduced significantly. In addition, several proposals are provided for hardening the devices.

Synthesis of polycarbonate diol catalyzed by metal-organic framework Zn_4O[CO_2-C_6H_4-CO_2]_3

The metal-organic framework Zn4O[1,4-benzenedicarboxylate]3(Zn4O[CO2-C6H4-CO2]3,commonly known as MOF-5,was prepared by the ultrasonic irradiation method.The catalyst was characterized by X-ray diffraction(XRD) and Fourier transform infrared(FTIR) spectroscopy.It was then used as the catalyst for the preparation of polycarbonate diol(PCDL) via the transesterification between diphenyl carbonate(DPC) and 1,6-hexandiol(1,6-HD).Its catalytic activity in the transesterification process is evaluated by the yield of phenol,and its catalytic activity in the polycondensation process is determined by the number-average molecular weight(Mn) and the hydroxyl value.Compared to the triethylenediamine(C6H12N2),Mg-Al layered double hydroxide(Mg-Al LDH),sodium ethoxide(C2H5ONa) and sodium methoxide(CH3ONa),MOF-5 exhibits highest catalytic activity for the preparation of PCDL.Under reaction conditions(n(1,6-HD)/n(DPC) = 1.2,w(catalyst) = 0.03%,198 ℃),the yield of phenol is up to 90.1% and the PCDL shows highest Mn and lowest hydroxyl value.

Preparation,characterization of Mo,Ag-loaded BiVO_4 and comparison of their degradation of methylene blue

Two types of metal-loaded visible-light-driven photocatalysts,Mo-BiVO4and Ag-BiVO4,were synthesized by wet impregnation method.Material poperties were characterized by UV-vis diffuse reflectance spectroscopy,X-ray diffraction,field emission scanning electron microscopy,X-ray photoelectron spectroscopy and low temperature nitrogen adsorption-desorption.Photocatalytic activity of the obtained materials was investigated through degrading methylene blue(MB) solution under visible-light irradiation.The results reveal that both metal loaded-BiVO4catalysts have monoclinic scheelite structure.Mo and Ag exist as oxides on the surface of the particles.The changes of absorption in visible-light region,band gap(E g) and specific surface area(A BET) caused by loading Ag are more obvious than those caused by loading Mo.But the isoelectric point of Ag-BiVO4decreases less than that of Mo-BiVO4does.Both catalysts show higher photocatalytic activity than pure BiVO4,resulting in the significantly improved efficiency of degradation of MB.And the degradation efficiency of these two metal-loaded BiVO4photocatalysts is similar to each other.However,mechanisms of such enhancement are different.The decrease of isoelectric point helps Mo-BiVO4improve the degradation efficiency.As for Ag-BiVO4,the augmentation of absorption in visible-light region as well as the abatement of E g plays more important roles.