[en] Objective: To explore a new scanning technique to reduce and avoid image artifacts of thoracoabdominal CT and improve image quality for patients who cannot raise their arms. Methods: Sixty-one patients with arm-raising disability between March 2004 and May 2009 were enrolled in the study. Thirty-one cases before June 2007 were scanned with their arms beside their body (control group), 30 cases after June 2007 were scanned with their arms shifting to different imaging planes of the spine (study group), and another 30 patients who can raising their arms were taken as routine group. The images artifacts were blindly evaluated by 5-points scale (severe, less severe, moderate, minimum and no artifact) by 2 experienced CT technologists and one radiologist and compared between the three groups (X² test). CT values and its noise of the liver with or without artifact of the three groups were measured and analyzed by one-way ANOVA test. Results: In the control group, 11 cases had severe, 15 cases had less severe, 5 cases had moderate. In the study group, 6 cases had moderate, 15 cases had minimum, 9 cases had no artifact. In the routine group, 8 cases minimum and 22 cases had no artifact. Image quality was significantly improved in the study group compared to the conventional group where X²=95.32 and P<0.01. CT value and the noise of the liver without artifact were (54.5 ± 3.0) HU and 10.7 ± 2.4 in the control group, (52.0 ± 3.5) HU and 10.7 ± 0.5 in the study group, (53.7 ± 3.1) HU and 9.9 ± 0.5 in the routine group, respectively. CT value and noise of the liver with artifact were (41.7 ± 8.4) HU and 17.9 ± 2.6 in control group, (53.1 ± 6.9) HU and 11.0 ± 0.7 in the study group, (54.1 ± 2.4) HU and 9.9 ± 0.5 in the routine group, respectively. The CT value and its noise variation with artifact were significantly higher in the control group than the study group and the control group, where F=36.352, 235.848, respectively and P<0.01. Conclusion: The image quality can be improved and the artifact can be minimized for the patients with arm-raising disability by shifting their arm position to the different imaging planes of the spine. (authors)

[en] Objective: To determine the reliability of CT perfusion scans and its parameters of γ-variate curve in evaluating the acute myocardial infarction for clinical reference of diagnosis on coronary artery disease and myocardial infarction. Methods: Imatron C-150 electron beam CT (EBCT) were used to scan a hydrodynamic model which could mimic a change of contrast medium by intravenous injection in vivo. Then 6 adult canines were employed in the experiment with thoracic operation, and branches of the anterior descending and circumflex of left coronary arteries (LCA) were ligated so that myocardial infarction was made out. After intravenous administration of contrast medium, the hearts were scanned with perfusion EBCT and γ-variate curves were manifested. Some heterogeneities and differentiations between the normality and the infarctions were put forward when the parameters of all these curves were analyzed and statistically processed. Two myocardial infarctions were also verified by SPECT, and all the samples stained with TTC method were compared with those on the perfusion images. The pathological study with optical microscope and electron microscope were further carried on. Results: The ascending slopes of γ-variate curves were different in the perfusion quantity. The normal curve of canine myocardium showed a somewhat quick ascending pattern first, and then a gradual descending pattern successively, with the ascending time of about 10-13 s, ascending CT value of about 34-37 HU, and peak CT value of about 70-81 HU. Whereas the curve on myocardial infarction demonstrated a prolonged ascending time of about 19.9 s, diminished ascending CT value of only about 20 HU, and peak CT value of about 53.8 HU, which were significantly different from the normality (P<0.05). Conclusion: There are some differences in γ-variate curves between normal myocardium and myocardial infarction, which can be detected by CT perfusion scan. (authors)

[en] To solve the dynamical consensus problem of second-order multi-agent systems with communication delay, delay-dependent compensations are added into the normal asynchronously-coupled consensus algorithm so as to make the agents achieve a dynamical consensus. Based on frequency-domain analysis, sufficient conditions are gained for second-order multi-agent systems with communication delay under leaderless and leader-following consensus algorithms respectively. Simulation illustrates the correctness of the results. (interdisciplinary physics and related areas of science and technology)

[en] Highlights: • Conventional geo-accumulation index ignores the uncertainty in observation data. • Stochastic geo-accumulation model (SGM) takes this uncertainty into consideration. • SGM has better capacities in uncertainty analysis and risk recognizing. • SGM has a better capacity in synthetic pollution evaluation. -- Abstract: The uncertainties introduced by sampling errors, measurement errors, and sediment heterogeneity in the evaluation of heavy metal pollution in the sediment of Poyang Lake are inevitable. The conventional geo-accumulation index (IGeo) cannot overcome these uncertainties. Thus, a stochastic geo-accumulation model (SGM) is established to solve this problem. In the SGM, the distribution of the heavy metal's concentration is stimulated by maximum entropy principle. Then, a membership vector is designed to quantify the pollution condition of each pollutant. Finally, a synthetic membership vector is generated to represent the comprehensive situation of heavy metal pollution in the sediment. SGM is applied in the evaluation of heavy metal pollution in four wetlands of Poyang Lake. Results show that (i) the SGM exhibits better capabilities in uncertainty analysis, risk recognition, and comprehensive pollution evaluation than the conventional IGeo and Hakanson index (HI) models. (ii) The pollution grade of heavy metals in the sediment of Longkou Wetland is “moderately contaminated,” whereas the pollution categories in Nanjishan, Wucheng, and Baishazhou wetlands are “uncontaminated to moderately contaminated.” (iii) Copper and lead are the key risk factors in Poyang Lake.

[en] In this paper, the morphology of the acupuncture point (abbreviated as acupoint hereafter) or tissue where there were no acupoints in the fractional rabbit hind limb was studied by in-line phase contrast CT imaging (PCI-CT) methods based on synchrotron radiation. The density of micro-vessels was calculated for tissues with acupoints or without acupoints. Differences between acupoints area and non-acupoint areas determined by the density of the micro-vessels propose a strong evidence of the existence of acupoints. Our results showed that there were two significantly higher densities of the micro-vessels, where two acupoints were located, respectively. In addition, there were large numbers of involutedly microvascular structure in the acupoint areas. Nevertheless, in non-acupoints area, the microvascular structure was relatively simple and flat

[en] A crystalline triazine organic framework (CTF-1) has been synthesized experimentally (Angewandte International Edition chemie, 2007, 47, 3450–345). However, there are few researches on it as a photocatalyst. The electronic structure and optical properties of CTF-1 were studied by first-principles calculations. Through the band edge and the absorption spectrum of CTF-1, we found that it can be used as organic photocatalyst. In addition, we have also found that the use of multilayer stacking and increasing nitrogen content can effectively reduce the band gap, and improve the range of light absorption.

[en] In this paper, a novel reagentless amprometric immunosensor was built on the conductive multilayer, comprised of Nafion-coated multi-wall carbon nanotubes (MWCNT), thionine (Thi) and gold nanoparticles (nano-Au). First, Nafion-MWCNT homogeneous composite was dropped on the surface of the glass carbon electrode (GCE). Then Thi was chemisorbed by both carboxylic MWCNT and cation exchanger Nafion. Furthermore, the negative-charged nano-Au, which was used to immobilize biomolecules, was chemisorbed onto Thi film through the electrostatic force with the amino groups of Thi. The stepwise self-assembly process of the immunosensor was characterized by means of cyclic voltammetry (CV), and the microstructure of modified film was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Using α-1-fetoprotein (AFP) as a model, this novel immunosensor presented amplified sensitivity, good stability, and a broader linear response in two ranges from 0.5-20 ng/mL and 20-200 ng/mL with a detection limit of 0.26 ng/mL, as well as good selectivity and storage stability.