ABSTRACT Objective Modic changes (MCs) classification system is the most widely used method in magnetic resonance imaging (MRI) for characterizing subchondral vertebral marrow changes. However, it shows a high degree of sensitivity to variations in MRI because of its semiquantitative nature. In 2021, the authors of this classification system further proposed a quantitative and reliable MC grading method. However, automated tools to grade MCs are lacking. This study developed and investigated the performance of convolutional neural network (CNN) in detecting and grading MCs based on their maximum vertical extent. In order to verify performance, we tested CNNs' generalization performance, the performance of CNN with that of junior doctors, and the consistency of junior doctors after AI assistance. Methods A retrospective analysis of 139 patients' MRIs with MCs was conducted and annotated by a spine surgeon. Of the 139 patients, MRIs from 109 patients were acquired using Philips scanners from June 2020 to June 2021, constituting Dataset 1. The remaining 30 patients had MRIs obtained from both Philips and United Imaging scanners from June 2022 to March 2023, forming Dataset 2. YOLOv8 and YOLOv5 were developed in PyCharm using the Python language and based on the PyTorch deep learning framework, data enhancement and transfer learning were applied to enhance model generalization. The model's performance was compared with precision, recall, F1 score, and mAP50. It also tested generalizability and compared it with the junior doctor's performance on the second data set (Dataset 2). Post hoc, the junior doctor graded Dataset 2 with CNN assistance. In addition, the region of interest was displayed using the class activation mapping heat map. Results On the unseen test set, the YOLOv8 and YOLOv5 models achieved precision of 81.60% and 61.59%, recall of 80.90% and 67.16%, mAP50 of 84.40% and 68.88%, and F1 of 0.81 and 0.60 respectively. On Dataset 2, YOLOv8 and junior doctor achieved precision of 95.1% and 72.5%, recall of 68.3% and 60.6%. In the AI‐assisted experiment, agreement between the junior doctor and the senior spine surgeon significantly improved from Cohen's kappa of 0.368–0.681. Conclusions YOLOv8 in detecting and grading MCs was significantly superior to that of YOLOv5. The performance of YOLOv8 is superior to that of junior doctors, and it can enhance the capabilities of junior doctors and improve the reliability of diagnoses.
Abstract Failure analysis (FA) was encountered as a ion charging risk when using focused ion beam to insert extra test pads for mixed signal integrated circuits (IC) on silicon on insulator (SOI). To overcome this challenge, and to precisely locate the open circuit defect, this paper described an effective non-destructive FA method based on dynamic InGaAs photon emission microscopy and schematic/layout analysis to determine the open circuit type and position. Nano-probing and electron beam absorbed current was used to located the precise location of the open circuit defect. Two typical samples of mixed signal IC on SOI were used (Samples 1 and 2, with extra and missing emission spots, respectively) to illustrate the analysis procedure and effectiveness for the proposed method. Scanning electron microscope results were presented to verify the accuracy of this method. It was demonstrated that the proposed method was able to accurately determine failure of open circuit efficiently without microprobe for mixed signal IC on SOI.
Shape modification of curves or surfaces is an important process in computer geometric modeling. This paper presents a new method to modify NURBS curves so that their shapes satisfy specified geometric constraints such as points and tangent vectors at more than one selected parametric points. The main idea of this method is given as follows: Firstly, some new conceptions are introduced, such as local curve, total curve, redundant constraints and redundant curve etc. For every parametric point, after computing a set of local curves that satisfy constraints at those parametric points respectively, one total curve consisting of those local curves is constructed. Subsequently, one redundant curve satisfying the redundant constraints is interpolated. Finally, applying the idea of constructing Coons surface, the modified curve that equals to the redundant curve subtracted from the total curve is obtained. Meanwhile, as a byproduct, authors find two existing methods are actually the same one. Examples show that the proposed approach is applicable for CAD systems.
Treatment-resistant depression (TRD) may have different physiopathological neuromechanism in different age groups. This study used the amplitude of low frequency fluctuations (ALFF) to initially compare abnormalities in local functional brain activity in younger and older patients with TRD.A total of 21 older TRD patients, 19 younger TRD, 19 older healthy controls (HCs), and 19 younger HCs underwent resting-state functional MRI scans, and the images were analyzed using the ALFF and further analyzed for correlation between abnormal brain regions and clinical symptoms in TRD patients of different age groups.Compared with the older TRD, the younger TRD group had increased ALFF in the left middle frontal gyrus and decreased ALFF in the left caudate nucleus. Compared with the matched HC group, ALFF was increased in the right middle temporal gyrus and left pallidum in the older TRD group, whereas no significant differences were found in the younger TRD group. In addition, ALFF values in the left middle frontal gyrus in the younger TRD group and in the right middle temporal gyrus in the older TRD were both positively correlated with the 17-item Hamilton Rating Scale for Depression score.Different neuropathological mechanisms may exist in TRD patients of different ages, especially in the left middle frontal gyrus and left caudate nucleus. This study is beneficial in providing potential key targets for the clinical management of TRD patients of different ages.
Abstract Carbon dots (CDs) phosphors in white laser diodes (WLD) have the advantages of sufficient surface functionalization sites and low cost. Specially, their color rendering index (CRI) in WLD is unsatisfactory due to the uncontrollable synthesis process and low thermal stability. Herein, surface nitrogen‐containing groups of CDs are synthesized from phenylenediamine isomers and trimeric acid, and the optical and thermal properties of CDs are modulated by introducing amide bonds (–CONH). By varying the phenylenediamine isomers, CDs synthesized from o ‐phenylenediamine, m ‐phenylenediamine, and p ‐phenylenediamine emit different fluorescence peaks at 534, 498, and 434 nm, respectively. Further investigation shows that the increase of –CONH and adjacent –NH 2 favors the reduction of bandgap, which in turn induces redshifted emission. The green‐emitting CDs are also found to be thermally stable at high –CONH contents up to 10.35%. Finally, by assembling the fluorescent film with 450 nm laser diode, WLD with color coordinates of (0.3767, 0.3540), correlated color temperature of 3924 K, and CRI of 87 is realized, and its CRI reaches the advancing value for single phosphors‐based WLD devices. This work will lay the theoretical and experimental foundation for the realization of the low‐cost, high photothermal stability, high‐color‐rendering‐index CDs‐based laser lighting devices.
Previous studies found that transcutaneous auricular vagus nerve stimulation (taVNS) was clinically effective in treating a case of treatment-resistant depression (TRD). However, the brain neural mechanisms underlying the immediate effects of taVNS treatment for TRD have not been elucidated.Differences in the amplitude of low-frequency fluctuations (ALFF) between TRD and healthy control (HC) groups were observed. The TRD group was treated with taVNS for 30 min, and changes in ALFF in the TRD group before and after immediate treatment were observed. The ALFF brain regions altered by taVNS induction were used as regions of interest to analyze whole-brain functional connectivity (FC) changes in the TRD group.A total of 44 TRD patients and 44 HCs completed the study and were included in the data analysis. Compared with the HC group, the TRD group had increased ALFF in the left orbital area of the middle frontal gyrus. After taVNS treatment, ALFF in the left orbital area of the middle frontal gyrus and right middle frontal gyrus decreased in the TRD group, while ALFF in the right orbital area of the superior frontal gyrus increased. The FC in the left orbital area of the middle frontal gyrus with left middle frontal gyrus and the right inferior occipital gyrus was significantly increased.Transcutaneous auricular vagus nerve stimulation demonstrates immediate modulation of functional activity in the emotional network, cognitive control network, and visual processing cortex, and may be a potential brain imaging biomarker for the treatment of TRD.
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