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R-zones are important part of the skin-stiffener joint in composite panels. Owing to their complex geometric shapes, defect behaviour, and poor accessibility, it is difficult to perform non-destructive testing and evaluation of their defects. A new method based on reflection behaviour generated by mono-pulse ultrasonic (MU) waves in R-zones for characterising and evaluating their defects was developed. Specimens with artificial and actual delaminations were used. The MU reflection behaviours, time-domain signals, and image characteristics originating from the R-zones were studied. Optical microscopy experiments were conducted to verify the MU results. Methods for discriminating the delamination and resin layer as well as determining their accurate depth were established using the MU signals from the R-zones. The experimental results show that delamination, resin layer, and pockets in the R-zones can be characterised and evaluated in detail using the MU method. Its resolution and dead zone reached 1 prepreg ply thickness. The minimum deviation of the layup depth of the detected delamination and resin layer in the R-zone is less than one prepreg ply thickness. Delaminations of ∅ 3 mm at different depths were detected reliably.
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Ondas Ultrasónicas , UltrasonidoRESUMEN
Objective To explore the effect of methadone maintenace treatment (MMT)in functional connectivity (FC)of nucleus accumbens (Nacc)on heroin addicts,and to identify the potential neuromechanism of MMT performing on heroin craving.Methods Craving scores and resting-state fMRI (rs-fMRI)were performed in 37 heroin addicts under MMT and 26 matched heroin addicts (HA) without any treatment.The rs-fMRI data preprocessing was performed by data processing assistant for rs-fMRI (DPARSF)soft-ware based on Matlab 2009a.Bilateral Naccs were set as regions of interesting (ROIs)respectively,and then the mean time series and other voxels within whole brain were analyzed by the rs-fMRI data analysis toolkit (REST).Intra-and inter-group analysis was performed with a single sample t-test and two sample t-test respectively.The partial correlation between the intensity of FC in brain regions showed abnormal FC and the duration/doses of methadone consumption was further investigated by SPSS.Craving scores were tested with two sample t-test.Results Inter-group analysis showed the FC of the right Nacc with left dorsal medial/lateral prefrontal cortex and right dorsal anterior cingulate was significantly increased in the MMT group in comparisonwith HA group,how-ever,it was decreased with right medial orbitofrontal cortex.The FC between the left Nacc and left dorsal medial/lateral prefrontal cortex,right dorsal lateral prefrontal cortex,right dorsal anterior cingulate and left insular cortex was also significantly increased in the MMT group (P 26,t=2.91).There were no regions with induced FC.The craving scores of MMT were signifi-cantly lower than those of HA (t = - 2.03,P <0.05 ).There was no significant correlation between the abnormal FC and the duration/doses of methadone consumption in MMT group.Conclusion MMT may influence the function of the nucleus accumbens through cognitive control and motivation/drive circuits,thereby reduce drug craving of heroin addicts.
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Objective To observe the effect of shock lymph drainage on multiple organ injury of rats with traumatic hemorrhagic shock (THS) and discuss the relating mechanism. Methods Male Wistar rats were divided into control group, lymph drainage group and lymph return group. The THS model was established in lymph drainage group and lymph return group, when the shock mesenteric lymph was drained in lymph drainage group. The change of the mean arterial pressure ( MAP), the biochemical indices of liver, kidney, myocardium and acid-base, the morphology, ATP contents and ATPase activities of lung, kidney, liver and myocardium were observed. Results The MAP at multiple time points after 80 minutes of infusion, the ATP contents and ATPase activities of multiple organs in lymph drainage group were higher than those in lymph return group. Multiple biochemical indices in lymph drainage group were superior to those in lymph return group, with statistical difference. The inflammation, congestion, degeneration and necrosis were found in organs of lymph return group, but only mild lesions could be seen in lymph drainage group. Conclusions The shock lymph drainage can alleviate multiple organ injury of THS rats, mechanism of which is correlated with improvement of the energy metabolism and maintenance of MAP and acid-base status.