Three Degrees of Freedom Global Calibration Method for Measurement Systems with Binocular Vision

Guan Xu,Xinyuan Zhang,Xiaotao Li,Jian Su,Xue Lu,Huanping Liu,Zhaobing Hao 한국광학회 2016 Current Optics and Photonics Vol.20 No.1

We develop a new method to globally calibrate the feature points that are derived from the binocularsystems at different positions. A three-DOF (degree of freedom) global calibration system is establishedto move and rotate the 3D calibration board to an arbitrary position. A three-DOF global calibration modelis constructed for the binocular systems at different positions. The three-DOF calibration model unifiesthe 3D coordinates of the feature points from different binocular systems into a unique world coordinatesystem that is determined by the initial position of the calibration board. Experiments are conducted onthe binocular systems at the coaxial and diagonal positions. The experimental root-mean-square errorsbetween the true and reconstructed 3D coordinates of the feature points are 0.573 mm, 0.520 mm and0.528 mm at the coaxial positions. The experimental root-mean-square errors between the true andreconstructed 3D coordinates of the feature points are 0.495 mm, 0.556 mm and 0.627 mm at the diagonalpositions. This method provides a global and accurate calibration to unity the measurement points ofdifferent binocular vision systems into the same world coordinate system.

Autophagy in Tumorigenesis and Cancer Treatment

Xu, Dong-Wei,Zhang, Guan-Qing,Wang, Zong-Wei,Xu, Xiao-Yin,Liu, Tong-Xiang Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.6

Autophagy is a self-digestion process, wrapping cytoplasmic proteins or organelles to form vesicles for degradation in lysosomes. The process plays an important role in the maintenance of intracellular homostasis. Here we overview articles on autophagy and cancer/tumors in Pubmed and found 327 articles. Autophagy exists in many tumors and is involved in cell malignant transformation and tumor cell growth. In early phases of tumorigenesis, autophagy clears the abnormally folded proteins and dysfunctional organelles such as mitochondria. Autophagy can also inhibit cell stress responses and prevent genetic damage. When a tumor develops, autophagy helps tumor cells survive nutritional deficiencies and hypoxic conditions. Studies of autophagy in the occurrence and progression of tumors should provide new therapeutic strategies for tumors.

Adaptable Center Detection of a Laser Line with a Normalization Approach using Hessian-matrix Eigenvalues

Guan Xu,Lina Sun,Jian Su,Zhaobing Hao,Xue Lu,Xiaotao Li 한국광학회 2014 Current Optics and Photonics Vol.18 No.4

In vision measurement systems based on structured light, the key point of detection precision is to determine accurately the central position of the projected laser line in the image. The purpose of this research is to extract laser line centers based on a decision function generated to distinguish the real centers from candidate points with a high recognition rate. First, preprocessing of an image adopting a difference image method is conducted to realize image segmentation of the laser line. Second, the feature points in an integral pixel level are selected as the initiating light line centers by the eigenvalues of the Hessian matrix. Third, according to the light intensity distribution of a laser line obeying a Gaussian distribution in transverse section and a constant distribution in longitudinal section, a normalized model of Hessian matrix eigenvalues for the candidate centers of the laser line is presented to balance reasonably the two eigenvalues that indicate the variation tendencies of the second-order partial derivatives of the Gaussian function and constant function, respectively. The proposed model integrates a Gaussian recognition function and a sinusoidal recognition function. The Gaussian recognition function estimates the characteristic that one eigenvalue approaches zero, and enhances the sensitivity of the decision function to that characteristic, which corresponds to the longitudinal direction of the laser line. The sinusoidal recognition function evaluates the feature that the other eigenvalue is negative with a large absolute value, making the decision function more sensitive to that feature, which is related to the transverse direction of the laser line. In the proposed model the decision function is weighted for higher values to the real centers synthetically, considering the properties in the longitudinal and transverse directions of the laser line. Moreover, this method provides a decision value from 0 to 1 for arbitrary candidate centers, which yields a normalized measure for different laser lines in different images. The normalized results of pixels close to 1 are determined to be the real centers by progressive scanning of the image columns. Finally, the zero point of a second-order Taylor expansion in the eigenvector’s direction is employed to refine further the extraction results of the central points at the subpixel level. The experimental results show that the method based on this normalization model accurately extracts the coordinates of laser line centers and obtains a higher recognition rate in two group experiments.

Effect of Insulin-like Growth Factor-1 on Bone Morphogenetic Protein-2 Expression in Hepatic Carcinoma SMMC7721 Cells through the p38 MAPK Signaling Pathway

Xu, Guan-Jun,Cai, Sheng,Wu, Jian-Bing Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

Objective: To observe the effect of insulin-like growth factor-1 (IGF-1) on bone morphogenetic protein (BMP)-2 expression in hepatocellular carcinoma SMMC7721 cells. Methods: Cells were divided into blank control, IGF-1, IGF-1 + SB203580, and SB203580 groups. SB203580 was used to block the p38 MAPK signaling pathway. Changes in the expression of BMP-2, p38 MAPK, and phosphorylated p38, MERK, ERK and JNK were determined using reverse transcription polymerase chain reactions (RT-PCR) and Western blot analysis. Results: Protein expression of phosphorylated BMP-2, MERK, ERK, and JNK was significantly up-regulated by IGF-1 compared with the control group ($1.138{\pm}0.065$ vs. $0.606{\pm}0.013$, $0.292{\pm}0.005$ vs. $0.150{\pm}0.081$, $0.378{\pm}0.006$ vs. $0.606{\pm}0.013$, and $0.299{\pm}0.015$ vs. $0.196{\pm}0.017$, respectively; P<0.05). Levels of BMP-2 and phosphorylated MERK and JNK were significantly reduced after blocking of the p38MAPK signaling pathway ($0.494{\pm}0.052$ vs. $0.165{\pm}0.017$, $0.073{\pm}0.07$ vs. $0.150{\pm}0.081$, and $0.018{\pm}0.008$ vs. $0.196{\pm}0.017$, respectively; P<0.05), but such a significant difference was not observed for phosphorylated ERK protein expression ($0.173{\pm}0.07$ vs. $0.150{\pm}0.081$, P>0.05). Conclusion: IGF-1 can up-regulate BMP-2 expression, and p38 MAPK signaling pathway blockage can noticeably reduce the up-regulated expression. We can conclude that the up-regulatory effect of IGF-1 on BMP-2 expression is realized through the p38 MAPK signaling pathway.

Precision Evaluation of Three-dimensional Feature Points Measurement by Binocular Vision

Guan Xu,Xiaotao Lin,Jian Su,Hongda Pan,Guangdong Tian 한국광학회 2011 Current Optics and Photonics Vol.15 No.1

Binocular-pair images obtained from two cameras can be used to calculate the three-dimensional (3D) world coordinate of a feature point. However, to apply this method, measurement accuracy of binocular vision depends on some structure factors. This paper presents an experimental study of measurement distance, baseline distance, and baseline direction. Their effects on camera reconstruction accuracy are investigated. The testing set for the binocular model consists of a series of feature points in stereo-pair images and corresponding 3D world coordinates. This paper discusses a method to increase the baseline distance of two cameras for enhancing the accuracy of a binocular vision system. Moreover, there is an inflexion point of the value and distribution of measurement errors when the baseline distance is increased. The accuracy benefit from increasing the baseline distance is not obvious, since the baseline distance exceeds 1000 mm in this experiment. Furthermore, it is observed that the direction errors deduced from the set-up are lower when the main measurement direction is similar to the baseline direction.

Application of Multilocus Sequence Analysis (MLSA) for Accurate Identification of Legionella spp. Isolated from Municipal Fountains in Chengdu, China, Based on 16S rRNA, mip, and rpoB Genes

Wang Guan,Ying Xu,Da-li Chen,Jia-nan Xu,Yu Tian,Jian-ping Chen 한국미생물학회 2012 The journal of microbiology Vol.50 No.1

Legionellosis (Legionnaires’ disease; LD) is a form of severe pneumonia caused by species of Legionella bacteria. Because inhalation of Legionella-contaminated aerosol is considered the major infection route, routine assessments of potential infection sources such as hot water systems, air-conditioner cooling water, and municipal fountains are of great importance. In this study, we utilized in vitro culture and multilocus sequence analysis (MLSA) targeting 16S rRNA, mip, rpoB, and mip-rpoB concatenation to isolate and identify Legionella spp. from 5 municipal fountains in Chengdu City, Sichuan Province, China. Our results demonstrated that 16S rRNA was useful for initial identification, as it could recognize isolates robustly at the genus level, while the genes mip, rpoB, and mip-rpoB concatenation could confidently discriminate Legionella species. Notably, the three subspecies of L. pneumophila could be distinguished by the analysis based on rpoB. The serotyping result of strain CD-1 was consistent with genetic analysis based on the concatenation of mip and rpoB. Despite regular maintenance and sanitizing methods, 4 of the 5 municipal fountains investigated in this study were positive for Legionella contamination. Thus, regularly scheduled monitoring of municipal fountains is urgently needed as well as vigilant disinfection. Although the application of MLSA for inspection of potential sites of infection in public areas is not standard procedure, further investigations may prove its usefulness.

Non-interfacial self-assembly of synthetic protocells

Xiaolin Xu,Wencai Guan,Xiaolei Yu,Guoxiong Xu,Chenglong Wang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Protocell refers to the basic unit of life and synthetic molecular assembly with cell structure and function. The protocells have great applications in the field of biomedical technology. Simulating the morphology and function of cells is the key to the preparation of protocells. However, some organic solvents used in the preparation process of protocells would damage the function of the bioactive substance. Perfluorocarbon, which has no toxic effect on bioactive substances, is an ideal solvent for protocell preparation. However, perfluorocarbon cannot be emulsified with water because of its inertia. Methods Spheroids can be formed in nature even without emulsification, since liquid can reshape the morphology of the solid phase through the scouring action, even if there is no stable interface between the two phases. Inspired by the formation of natural spheroids such as pebbles, we developed non-interfacial self-assembly (NISA) of microdroplets as a step toward synthetic protocells, in which the inert perfluorocarbon was utilized to reshape the hydrogel through the scouring action. Results The synthetic protocells were successfully obtained by using NISA-based protocell techniques, with the morphology very similar to native cells. Then we simulated the cell transcription process in the synthetic protocell and used the protocell as an mRNA carrier to transfect 293T cells. The results showed that protocells delivered mRNAs, and successfully expressed proteins in 293T cells. Further, we used the NISA method to fabricate an artificial cell by extracting and reassembling the membrane, proteins, and genomes of ovarian cancer cells. The results showed that the recombination of tumor cells was successfully achieved with similar morphology as tumor cells. In addition, the synthetic protocell prepared by the NISA method was used to reverse cancer chemoresistance by restoring cellular calcium homeostasis, which verified the application value of the synthetic protocell as a drug carrier. Conclusion This synthetic protocell fabricated by the NISA method simulates the occurrence and development process of primitive life, which has great potential application value in mRNA vaccine, cancer immunotherapy, and drug delivery.

Neutropenia during the First Cycle of Induction Chemotherapy Is Prognostic for Poor Survival in Locoregionally Advanced Nasopharyngeal Carcinoma: A Real-World Study in an Endemic Area

Cheng Xu,Shi-Ping Yang,Yuan Zhang,Ling-Long Tang,Guan-Qun Zhou,Xu Liu,Yan-Ping Mao,Rui Guo,Wen-Fei Li,Lei Chen,Ai-Hua Lin,Ying Sun,Jun Ma 대한암학회 2018 Cancer Research and Treatment Vol.50 No.3

Purpose The purpose of this study was to investigate the effect of neutropenia during the first cycle of induction chemotherapy (IC-1) on survival in locoregionally advanced nasopharyngeal carcinoma (LANPC). Materials and Methods Eligible patients (n=545) with LANPC receiving IC+concurrent chemoradiotherapy were included. Based on nadir neutrophil after IC-1, all patients were categorized into three groups: no/grade 1-2/grade 3-4 neutropenia. Five-year overall survival (OS) and disease-free survival (DFS) were compared between groups and subgroups stratified by IC regimen. We also explored the occurrence of IC-1–induced myelosuppression events and the minimal value of post-treatment neutrophil-to-lymphocyte ratio (post-NLRmin). Univariate/multivariate analyses were performed to investigate the effect of IC-1–induced neutropenia, timing of neutropenia, number of myelosuppression events, and high post-NLRmin on OS/DFS. Results Grade 1-2/grade 3-4 neutropenia were associated with poorer OS/DFS than no neutropenia (all p < 0.05); OS/DFS were not significantly different between patients experiencing grade 1-2 vs. 3-4 neutropenia. Neutropenia had no significant effect on OS/DFS in patients receiving docetaxel–cisplatin–5-fluorouracil (TPF). Grade 1-2 (grade 3-4) neutropenia negatively influenced OS/DFS in patients receiving cisplatin–5-fluorouracil (PF) (PF and docetaxel– cisplatin [TP]; all p < 0.05). Neutropenia, two/three myelosuppression events, and high post-NLRmin ( 1.33) was most frequent on days 5-10, second and third week of IC-1, respectively. After adjustment for covariates, IC-1–induced neutropenia, two/three myelosuppression events, and post-NLRmin  1.33 were validated as negative predictors of OS/DFS (all p < 0.05); timing of neutropenia had no significant effect. Conclusion Occurrence of neutropenia, number of myelosuppression events, and high post-NLRmin during PF/TP IC-1 have prognostic value for poor survival in LANPC.

Research on Peak-detection Algorithm for High-precision Demodulation System of Fiber Bragg Grating

Peng Wang,Xu Han,Simin Guan,Hong Zhao,Minglei Shao 보안공학연구지원센터 2014 International Journal of Hybrid Information Techno Vol.7 No.6

In order to improve the detection accuracy of wavelength, the filtering and curve fitting technologies were applied in the FBG wavelength demodulation system based on tunable F-P filter. These methods could realize the accurate peak-location of output signals of the photo detector. According to the characteristics of noise, the FIR low-pass filter was designed to filter the obtained light power signals so as to provide the input signals with high SNR for the peak-detection algorithms. By analyzing and comparing several typical peak-searching algorithms, the algorithm of Gauss formula nonlinear curve fitting (L-M) was chosen to fit the digitized light power signals. The experimental results show that L-M fitting algorithm reduces the mean square error by 7.5% compared with the Gauss fitting algorithm. For the Gauss signal in the wavelength demodulation system designed in the paper, the L-M algorithm has lower mean square error than other peak-searching algorithms. This algorithm is suitable for FBG wavelength demodulation system based on tunable F-P filter. It can efficiently raise the accuracy of wavelength demodulation system.

遼東及西北西北朝鮮靑銅時代陶壺的幾個問題

徐光輝 원광대학교 마한백제문화연구소 1993 馬韓, 百濟文化 Vol.13 No.-