36 results on '"Yikai Xu"'
Search Results
2. Uncovering strong π-metal interactions on Ag and Au nanosurfaces under ambient conditions via in-situ surface-enhanced Raman spectroscopy
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Chunchun Li, Zheng Chen, Yiming Huang, Yingrui Zhang, Xinyuan Li, Ziwei Ye, Xin Xu, Steven E.J. Bell, and Yikai Xu
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General Chemical Engineering ,Biochemistry (medical) ,Materials Chemistry ,Environmental Chemistry ,General Chemistry ,Biochemistry - Abstract
The interactions between aromatic molecules and metal nanoparticles are ubiquitous in nanotechnology. Currently, π-metal interactions under ambient conditions are well appreciated for VIIIB but not for IB metals. Here, we demonstrate the direct probing of π-metal interactions under ambient conditions with molecular specificity using surface-enhanced Raman spectroscopy (SERS), which reveals that aromatic hydrocarbons adsorb strongly from solution onto the surfaces of Ag and Au nanoparticles, provided there is no surface oxidation. Theoretical modeling shows that this adsorption is driven by dispersive π-metal interactions and that the aromatic molecules co-adsorb alongside surface ligands that are present initially on the nanosurface. Finding direct evidence for this long-neglected interaction has significant implications for various applications. This is demonstrated with SERS sensing of an aromatic drug molecule whose structure would typically suggest it to be weakly adsorbing, and indeed it is not detected on conventional Ag colloids due to surface oxidation, but it is found to adsorb strongly onto Au particles.
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- 2022
3. Predicting peritoneal recurrence and disease-free survival from CT images in gastric cancer with multitask deep learning: a retrospective study
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Yuming Jiang, Zhicheng Zhang, Qingyu Yuan, Wei Wang, Hongyu Wang, Tuanjie Li, Weicai Huang, Jingjing Xie, Chuanli Chen, Zepang Sun, Jiang Yu, Yikai Xu, George A Poultsides, Lei Xing, Zhiwei Zhou, Guoxin Li, and Ruijiang Li
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Medicine (miscellaneous) ,Health Informatics ,Disease-Free Survival ,Deep Learning ,Health Information Management ,Artificial Intelligence ,Predictive Value of Tests ,Stomach Neoplasms ,Humans ,Decision Sciences (miscellaneous) ,Neoplasm Recurrence, Local ,Tomography, X-Ray Computed ,Peritoneal Neoplasms ,Retrospective Studies - Abstract
Peritoneal recurrence is the predominant pattern of relapse after curative-intent surgery for gastric cancer and portends a dismal prognosis. Accurate individualised prediction of peritoneal recurrence is crucial to identify patients who might benefit from intensive treatment. We aimed to develop predictive models for peritoneal recurrence and prognosis in gastric cancer.In this retrospective multi-institution study of 2320 patients, we developed a multitask deep learning model for the simultaneous prediction of peritoneal recurrence and disease-free survival using preoperative CT images. Patients in the training cohort (n=510) and the internal validation cohort (n=767) were recruited from Southern Medical University, Guangzhou, China. Patients in the external validation cohort (n=1043) were recruited from Sun Yat-sen University Cancer Center, Guangzhou, China. We evaluated the prognostic accuracy of the model as well as its association with chemotherapy response. Furthermore, we assessed whether the model could improve the ability of clinicians to predict peritoneal recurrence.The deep learning model had a consistently high accuracy in predicting peritoneal recurrence in the training cohort (area under the receiver operating characteristic curve [AUC] 0·857; 95% CI 0·826-0·889), internal validation cohort (0·856; 0·829-0·882), and external validation cohort (0·843; 0·819-0·866). When informed by the artificial intelligence (AI) model, the sensitivity and inter-rater agreement of oncologists for predicting peritoneal recurrence was improved. The model was able to predict disease-free survival in the training cohort (C-index 0·654; 95% CI 0·616-0·691), internal validation cohort (0·668; 0·643-0·693), and external validation cohort (0·610; 0·583-0·636). In multivariable analysis, the model predicted peritoneal recurrence and disease-free survival independently of clinicopathological variables (p0·0001 for all). For patients with a predicted high risk of peritoneal recurrence and low survival, adjuvant chemotherapy was associated with improved disease-free survival in both stage II disease (hazard ratio [HR] 0·543 [95% CI 0·362-0·815]; p=0·003) and stage III disease (0·531 [0·432-0·652]; p0·0001). By contrast, chemotherapy had no impact on disease-free survival for patients with a predicted low risk of peritoneal recurrence and high survival. For the remaining patients, the benefit of chemotherapy depended on stage: only those with stage III disease derived benefit from chemotherapy (HR 0·637 [95% CI 0·484-0·838]; p=0·001).The deep learning model could allow accurate prediction of peritoneal recurrence and survival in patients with gastric cancer. Prospective studies are required to test the clinical utility of this model in guiding personalised treatment in combination with clinicopathological criteria.None.
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- 2022
4. Boosting electromagnetic enhancement for detection of non-adsorbing analytes on semiconductor SERS substrates
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Xinyu Liu, Ziwei Ye, Qian Xiang, Zehong Xu, Wenhui Yue, Chunchun Li, Yikai Xu, Lingzhi Wang, Xiaoming Cao, and Jinlong Zhang
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General Chemical Engineering ,Biochemistry (medical) ,Materials Chemistry ,Environmental Chemistry ,General Chemistry ,Biochemistry - Published
- 2023
5. Radiographical assessment of tumour stroma and treatment outcomes using deep learning: a retrospective, multicohort study
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Zhen Han, Qingyu Yuan, Guoxin Li, Ruijiang Li, Zhiwei Zhou, Jiang Yu, Tuanjie Li, Sujuan Xi, Na Li, Yaoqin Xie, Yikai Xu, Chuanli Chen, Xiaokun Liang, Wei Wang, Yuming Jiang, and George A. Poultsides
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Male ,Oncology ,China ,medicine.medical_specialty ,medicine.medical_treatment ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Medicine (miscellaneous) ,Health Informatics ,Disease-Free Survival ,Deep Learning ,Health Information Management ,Stroma ,Predictive Value of Tests ,Stomach Neoplasms ,Internal medicine ,Biomarkers, Tumor ,medicine ,Humans ,Decision Sciences (miscellaneous) ,Stage (cooking) ,Proportional Hazards Models ,Retrospective Studies ,Chemotherapy ,Receiver operating characteristic ,business.industry ,Stomach ,Hazard ratio ,Cancer ,Retrospective cohort study ,Middle Aged ,Prognosis ,medicine.disease ,Progression-Free Survival ,Radiography ,ROC Curve ,Chemotherapy, Adjuvant ,Area Under Curve ,Cohort ,Female ,Neural Networks, Computer ,Tomography, X-Ray Computed ,business - Abstract
Summary: Background: The tumour stroma microenvironment plays an important part in disease progression and its composition can influence treatment response and outcomes. Histological evaluation of tumour stroma is limited by access to tissue, spatial heterogeneity, and temporal evolution. We aimed to develop a radiological signature for non-invasive assessment of tumour stroma and treatment outcomes. Methods: In this multicentre, retrospective study, we analysed CT images and outcome data of 2209 patients with resected gastric cancer from five independent cohorts recruited from two centres (Nanfang Hospital of Southern Medical University [Guangzhou, China] and Sun Yat-sen University Cancer Center [Guangzhou, China]). Patients with histologically confirmed gastric cancer, at least 15 lymph nodes harvested, preoperative abdominal CT available, and complete clinicopathological and follow-up data were eligible for inclusion. Tumour tissue was collected for patients in the training cohort (321 patients), internal validation cohort one (246 patients), and external validation cohort one (128 patients). Four stroma classes were defined according to the protein expression of α-smooth muscle actin and periostin assessed by immunohistochemistry. The primary objective was to predict the histologically based stroma classes by using preoperative CT images. We trained a deep convolutional neural network model using the training cohort and tested the model in the internal and external validation cohort one. We evaluated the model's association with prognosis in the training cohort, two internal, and two external validation cohorts and compared outcomes of patients who received or did not receive adjuvant chemotherapy. Findings: The deep-learning model achieved a high diagnostic accuracy for assessing tumour stroma in both internal validation cohort one (area under the receiver operating characteristic curve [AUC] 0·96–0·98]) and external validation cohort one (AUC 0·89–0·94). The stromal imaging signature was significantly associated with disease-free survival and overall survival in all cohorts (p
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- 2021
6. Aberrant Functional Connectivity of Basal Forebrain Subregions with Cholinergic System in Short-term and Chronic Insomnia Disorder
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Yunfan Wu, Guang Xu, Tianyue Wang, Mengchen Liu, Guihua Jiang, Xiaofen Ma, Shishun Fu, Yikai Xu, Yi Yin, and Junzhang Tian
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Cingulate cortex ,medicine.medical_specialty ,Basal Forebrain ,Cholinergic Agents ,Striatum ,Grey matter ,03 medical and health sciences ,0302 clinical medicine ,Sleep Initiation and Maintenance Disorders ,Internal medicine ,medicine ,Humans ,Clinical significance ,Gray Matter ,Basal forebrain ,business.industry ,Functional connectivity ,Epworth Sleepiness Scale ,Magnetic Resonance Imaging ,030227 psychiatry ,Psychiatry and Mental health ,Clinical Psychology ,Chronic insomnia ,Endocrinology ,medicine.anatomical_structure ,business ,030217 neurology & neurosurgery - Abstract
Background To systematically investigate structural and functional abnormalities in subregions of the basal forebrain (BF) using structural and resting-state fMRI, and to examine their clinical relevance in short-term and chronic insomnia disorder (ID). Methods Thirty-four patients with short-term ID, 41 patients with chronic ID, and 46 healthy controls (HCs) were recruited. Grey matter volume and seed-based resting-state functional connectivity (RSFC) in each BF subregion (Ch1,2,3 and 4) were computed and compared among the three groups. Spearman correlation was used to estimate the relationships between MRI-based alterations and clinical variables. Results The short-term group exhibited lower RSFC with the bilateral striatum and bilateral Ch_4 than HCs and the chronic group. In the left Ch_4, subjects in the chronic group exhibited lower RSFC with the left middle cingulate cortex than HCs and the short-term group. The short-term group exhibited lower RSFC with the left parahippocampal gyrus (PHG) than HCs and the chronic group. The chronic group exhibited the highest RSFC with the left middle frontal gyrus (MFG), followed by HCs and the short-term group. In the right Ch_4, the chronic group exhibited the lowest RSFC with the right superior temporal gyrus, followed by HCs and the short-term group. Moreover, in the short-term group, negative correlations were found between the left Ch_4 and left MFG RSFC and Epworth Sleepiness Scale scores. Conclusions These findings suggest that the Ch_4 may be a key node for establishing diagnostic and categorical biomarkers of ID, which could be useful in developing more effective treatment strategies for insomnia.
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- 2021
7. Noninvasive imaging evaluation of tumor immune microenvironment to predict outcomes in gastric cancer
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Yikai Xu, Ruijiang Li, Chuanli Chen, Guoxin Li, Tuanjie Li, Yuming Jiang, Hongxia Wang, Qingyu Yuan, Jia Wu, Weicai Huang, Zhiwei Zhou, Yanfeng Hu, and Sujuan Xi
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0301 basic medicine ,Oncology ,medicine.medical_specialty ,medicine.medical_treatment ,Immune microenvironment ,Logistic regression ,03 medical and health sciences ,0302 clinical medicine ,Stomach Neoplasms ,Internal medicine ,Tumor Microenvironment ,medicine ,Humans ,Prospective Studies ,Prospective cohort study ,Retrospective Studies ,Chemotherapy ,business.industry ,Hazard ratio ,Cancer ,Retrospective cohort study ,Hematology ,Prognosis ,medicine.disease ,030104 developmental biology ,Chemotherapy, Adjuvant ,030220 oncology & carcinogenesis ,Immunohistochemistry ,business - Abstract
Background The tumor immune microenvironment can provide prognostic and predictive information. A previously validated ImmunoScore of Gastric Cancer (ISGC) evaluates both lymphoid and myeloid cells in the tumor core and invasive margin with immunohistochemical staining of surgical specimens. We aimed to develop a noninvasive radiomics-based predictor of ISGC. Patients and methods In this retrospective study including four independent cohorts of 1778 patients, we extracted 584 quantitative features from the intratumoral and peritumoral regions on contrast-enhanced computed tomography images. A radiomic signature [radiomics ImmunoScore (RIS)] was constructed to predict ISGC using regularized logistic regression. We further evaluated its association with prognosis and chemotherapy response. Results A 13-feature radiomic signature for ISGC was developed and validated in three independent cohorts (area under the curve = 0.786, 0.745, and 0.766). The RIS signature was significantly associated with both disease-free and overall survival in the training and all validation cohorts [hazard ratio (HR) range: 0.296–0.487, all P Conclusion The RIS is a reliable tool for evaluation of immunoscore and retains the prognostic significance in gastric cancer. Future prospective studies are required to confirm its potential to predict treatment response and select patients who will benefit from chemotherapy.
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- 2020
8. Comprehensive Analysis of Biochar-Based Co2 Capture
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Chen Zhang, Ying Ji, Chunchun Li, Yingrui Zhang, Shuzhuang Sun, Yikai Xu, Long Jiang, and Chunfei Wu
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
9. Association of Habitual Glucosamine Use with Risk of Dementia: Prospective Study in UK Biobank
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Deying Liu, Bingquan Lin, Linna Shi, Peizhen Zhang, Jiayang Lin, Xueyun Wei, Chensihan Huang, Bingyan Huang, Junlin Huang, Xuzhen Lei, Dan Guo, Yating Liu, Linjie Yang, Yikai Xu, and Huijie Zhang
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
10. Cycloacceleration of ferroptosis and calcicoptosis for magnetic resonance imaging-guided colorectal cancer therapy
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Shuai Guo, Zongheng Li, Jie Feng, Wei Xiong, Jing Yang, Xuanyi Lu, Sugeun Yang, Yikai Xu, Aiguo Wu, and Zheyu Shen
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Biomedical Engineering ,Pharmaceutical Science ,General Materials Science ,Bioengineering ,Biotechnology - Published
- 2022
11. A one-pot method for building colloidal nanoparticles into bulk dry powders with nanoscale magnetic, plasmonic and catalytic functionalities
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Chunchun Li, Ziwei Ye, Yikai Xu, Peter K. J. Robertson, Nathan Skillen, Steven E. J. Bell, Hannah McCabe, and Jessica Kelly
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chemistry.chemical_classification ,Aqueous solution ,Materials science ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Pickering emulsion ,0104 chemical sciences ,Colloid ,chemistry ,Magnetic nanoparticles ,General Materials Science ,Surface layer ,0210 nano-technology ,Nanoscopic scale - Abstract
Building easy-to-handle bulk materials with nanoproperties is crucial for many nanotechnology-based real-world applications. Here, we describe a simple one-pot method based on nanoparticle self-assembly of pickering emulsions and in situ polymer deposition for preparing particles consisting of a rigid micro-polymer core covered in exposed surface layers of nanoparticles, which we have named nano-micro-particles (NMPs). Unlike simple colloids, these NMPs can be filtered off from the aqueous suspensions in which they are prepared and dried to form free-flowing powders, which most importantly, retain the properties of the constituent nanoparticles in the surface layer. These NMPs can be stored for extended periods but then used either in the dry state or be re-suspended into liquid media as required. The preparation method is very general and can be readily extended to assemble various types of nanoparticles regardless of their material composition or morphology. In addition, functional components, such as magnetic particles or fluorescent tags, can be encapsulated within the polymer core. This method is a platform technology for building nanoparticles into bulk materials with nano-functionalities tailored toward real-life applications. This is illustrated with examples of the preparation of NMPs suitable for rapid and low-cost on-site water monitoring and remediation.
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- 2019
12. Whole-tumor histogram analysis of apparent diffusion coefficient in differentiating intracranial solitary fibrous tumor/hemangiopericytoma from angiomatous meningioma
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Wenle He, Jun Zhou, Xiaodan Li, Yikai Xu, Yihao Guo, Xiaomin Liu, Xiang Xiao, Liuji Guo, and Yuankui Wu
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Adult ,Male ,Percentile ,Solitary fibrous tumor ,Infratentorial Neoplasms ,Skull Base Neoplasms ,030218 nuclear medicine & medical imaging ,Diagnosis, Differential ,03 medical and health sciences ,0302 clinical medicine ,Histogram ,Meningeal Neoplasms ,Humans ,Medicine ,Effective diffusion coefficient ,Radiology, Nuclear Medicine and imaging ,Aged ,Hemangiopericytoma ,Receiver operating characteristic ,business.industry ,General Medicine ,Middle Aged ,medicine.disease ,Diffusion Magnetic Resonance Imaging ,Solitary Fibrous Tumors ,030220 oncology & carcinogenesis ,Mann–Whitney U test ,Kurtosis ,Female ,Epidemiologic Methods ,Meningioma ,business ,Nuclear medicine - Abstract
Purpose To assess the role of histogram analysis of apparent diffusion coefficient (ADC) maps based on whole-tumor in differentiating intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) from angiomatous meningioma (AM). Materials and methods Pathologically confirmed intracranial SFT/HPC (n = 15) and AM (n = 20) were retrospectively collected and their clinical and conventional MRI features were analyzed. Diffusion-weighted (DW) images (b = 0 and 1000 s/mm2) were processed with the mono-exponential model. Regions of interest covering the whole tumor were drawn on all slices of the ADC maps to obtain histogram parameters, including mean ADC (ADCmean), median ADC (ADCmedian), maximum ADC (ADCmax), minimum ADC (ADCmin), skewness and kurtosis, as well as the 5th, 10th, 25th, 75th, 90th and 95th percentile ADC (ADC5, ADC10, ADC25, ADC75, ADC90 and ADC95). Differences of histogram parameters between SFT/HPC and AM were compared using Mann-Whitney U test. Receiver operating characteristic (ROC) curve was used to determine the diagnostic performance. Results The ADCmin (P = 0.001) and ADC5 (P = 0.045) were significantly lower in SFT/HPCs than in AMs, while no significant difference was found in sex, age, conventional MRI features or any other histogram parameters between the two entities (P = 0.051−1.000). ADCmin showed the best diagnostic performance (area under curve [AUC], 0.86; sensitivity, 81.3%; specificity, 83.3%) in differentiating SFT/HPC from AM with optimal cutoff value being 569.00 × 10−6 mm2/s, followed by ADC5 (AUC, 0.72; sensitivity, 68.8%; specificity, 75%) with optimal cutoff value being 781.97 × 10−6 mm2/s. Conclusion SFT/HPC and AM share similar conventional MR appearances. Whole-tumor histogram analysis of ADC maps may be a useful tool for differential diagnosis, with ADCmin and ADC5 being potential parameters.
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- 2019
13. Developed and validated a prognostic nomogram for recurrence-free survival after complete surgical resection of local primary gastrointestinal stromal tumors based on deep learning
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Yu Zhang, Cangui Zhang, Hao Chen, Mingli Zhao, Tao Chen, Shangqing Liu, Tian Lin, Wei Xiong, Yanfeng Hu, Yikai Xu, Yali Yang, Jiang Yu, Hao Liu, Yong Li, Guoxin Li, Xingyu Feng, and Xixi Zhao
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Adult ,Male ,0301 basic medicine ,Surgical resection ,medicine.medical_specialty ,Research paper ,genetic structures ,Gastrointestinal Stromal Tumors ,lcsh:Medicine ,urologic and male genital diseases ,Disease-Free Survival ,General Biochemistry, Genetics and Molecular Biology ,Residual neural network ,Residual Neural Network ,03 medical and health sciences ,Deep Learning ,0302 clinical medicine ,Recurrence free survival ,Adjuvant therapy ,Humans ,Medicine ,Aged ,Gastrointestinal Neoplasms ,Retrospective Studies ,lcsh:R5-920 ,business.industry ,lcsh:R ,External validation ,General Medicine ,Middle Aged ,Nomogram ,Prognosis ,Training cohort ,Nomograms ,030104 developmental biology ,Recurrence-free Survival ,030220 oncology & carcinogenesis ,Imatinib ,Cohort ,Female ,Radiology ,lcsh:Medicine (General) ,business - Abstract
This study aimed to develop and validate a prognostic nomogram for recurrence-free survival (RFS) after surgery in the absence of adjuvant therapy to guide the selection for adjuvant imatinib therapy based on Residual Neural Network (ResNet).The ResNet model was developed based on contrast-enhanced computed tomography (CE-CT) in a training cohort consisted of 80 patients pathologically diagnosed gastrointestinal sromal tumors (GISTs) and validated in internal and external validation cohort respectively. Independent clinicopathologic factors were integrated with the ResNet model to construct the individualized nomogram. The performance of the nomogram was evaluated in regard to discrimination, calibration, and clinical usefulness.The ResNet model was significantly associated with RFS. Integrable predictors in the individualized ResNet nomogram included the tumor site, size, and mitotic count. Compared with modified NIH, AFIP, and clinicopathologic nomogram, both ResNet nomogram and ResNet model showed a better discrimination capability with AUCs of 0·947(95%CI, 0·910–0·984) for 3-year-RFS, 0·918(0·852–0·984) for 5-year-RFS, and AUCs of 0·912 (0·851–0·973) for 3-year-RFS, 0·887(0·816–0·960) for 5-year-RFS, respectively. Calibration curve shows the good calibration of the nomogram in terms of the agreement between the estimated and the observed 3- and 5- year outcomes. Decision curve analysis showed that the ResNet nomogram had a higher overall net benefit.In conclusion, we presented a deep learning-based prognostic nomogram to predict RFS after resection of localized primary GISTs with excellent performance and could be a potential tool to select patients for adjuvant imatinib therapy. Keywords: Gastrointestinal Stromal Tumors, Deep Learning, Residual Neural Network, Recurrence-free Survival, Imatinib
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- 2019
14. Production and testing of novel photocatalytic TiO2 surface-exposed nanoparticle (TiO2-SEN) thin plastic films
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Andrew Mills, Steven E. J. Bell, Xinyuan Li, Yikai Xu, Aaron McNeill, and Nathan Wells
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Tetraphenylborate ,Chemistry ,Scanning electron microscope ,General Chemical Engineering ,General Physics and Astronomy ,Nanoparticle ,02 engineering and technology ,General Chemistry ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Coating ,Chemical engineering ,Phase (matter) ,Monolayer ,Photocatalysis ,engineering ,Polystyrene ,0210 nano-technology - Abstract
Thin, flexible, surface-active, polystyrene-based, optically transparent films, embedded with a coating of commercially sourced titanium dioxide nanoparticles (Evonik P25), are made by coupling protonated TiO2 particles with an anionic phase transfer agent (tetraphenylborate), to create an ion-paired species that is drawn to a water/dichloromethane (DCM) interface to form a monolayer. The latter is subsequently embedded in a thin polystyrene (PS) film, typically 2.5 μm thick, by allowing the DCM to evaporate. The resulting clear TiO2 Surface-Exposed Nanoparticle (TiO2-SEN) thin plastic films are characterised using scanning electron microscopy (SEM) and found to have 25.3 ± 5.4 nm TiO2 nanoparticles exposed to the air on one side and PS on the other. The photocatalytic activity of these films is demonstrated using a number of different tests including: the photo-oxidation of 4-chlorophenol (4-CP) and methylene blue (MB) and the photoreduction of resazurin (Rz) and MB. In most of these tests the photoactivity of the film is more than double compared to that of a commercial photocatalytic film, Activ™.
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- 2019
15. Pressing solids directly into sheets of plasmonic nanojunctions enables solvent-free surface-enhanced Raman spectroscopy
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Jessica Kelly, Steven E. J. Bell, Hannah McCabe, Ziwei Ye, Yikai Xu, and Chunchun Li
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Materials science ,Nanotechnology ,02 engineering and technology ,Substrate (electronics) ,Surface-enhanced Raman spectroscopy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Spectral line ,0104 chemical sciences ,Solvent ,symbols.namesake ,symbols ,Molecule ,General Materials Science ,0210 nano-technology ,Raman spectroscopy ,Dissolution ,Plasmon - Abstract
Often chemical analysis of solid materials begins with dissolving the sample in a solvent but this is undesirable, particularly if the physical form is important. In principle surface-enhanced Raman spectroscopy (SERS) should allow detection of solid analytes and offers attomolar sensitivity combined with molecular specificity. SERS requires the target molecules to sit in plasmonic hot-spots, which are normally nanojunctions, just a few nm across. This means that solid samples normally need to be dissolved in a solvent so they can diffuse into the enhancing region. Here, we show that SERS spectra of picograms of solid analytes can be directly obtained by pressing them into a flexible SERS substrate with a dense field of exposed nanojunction hot-spots anchored on its surface. We demonstrate that this can be a powerful tool for straightforward and non-destructive forensic analysis of layered materials (crossing ink lines), solid explosives and illicit drugs as well as for studying previously intractable samples such as pharmaceutical co-crystals, whose important solid state structure is lost when they are dissolved.
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- 2018
16. Radiomics signature of computed tomography imaging for prediction of survival and chemotherapeutic benefits in gastric cancer
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Jingjing Xie, Yikai Xu, Wei Wang, Chuanli Chen, Guoxin Li, Jiang Yu, Hao Chen, Wenbing Lv, Yuming Jiang, Xuefan Zha, Zhiwei Zhou, Tuanjie Li, and Yanfeng Hu
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Adult ,Male ,Oncology ,medicine.medical_specialty ,Research paper ,Multivariate analysis ,Radiomics signature ,Computed tomography ,Comorbidity ,TNM staging system ,Stage ii ,General Biochemistry, Genetics and Molecular Biology ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Radiomics ,Stomach Neoplasms ,Internal medicine ,Antineoplastic Combined Chemotherapy Protocols ,Image Processing, Computer-Assisted ,Humans ,Chemotherapy ,Medicine ,Aged ,Neoplasm Staging ,medicine.diagnostic_test ,business.industry ,External validation ,Reproducibility of Results ,Cancer ,General Medicine ,Middle Aged ,Nomogram ,Prognosis ,medicine.disease ,Treatment Outcome ,ROC Curve ,030220 oncology & carcinogenesis ,Female ,Neoplasm Grading ,Tomography, X-Ray Computed ,Gastric cancer ,business ,Biomarkers - Abstract
To develop and validate a radiomics signature for the prediction of gastric cancer (GC) survival and chemotherapeutic benefits. In this multicenter retrospective analysis, we analyzed the radiomics features of portal venous-phase computed tomography in 1591 consecutive patients. A radiomics signature was generated by using the Lasso-Cox regression model in 228 patients and validated in internal and external validation cohorts. Radiomics nomograms integrating the radiomics signature were constructed, demonstrating the incremental value of the radiomics signature to the traditional staging system for individualized survival estimation. The performance of the nomograms was assessed with respect to calibration, discrimination, and clinical usefulness. The radiomics signature consisted of 19 selected features and was significantly associated with DFS (disease-free survival) and OS (overall survival). Multivariate analysis demonstrated that the radiomics signature was an independent prognostic factor. Incorporating the radiomics signature into the radiomics-based nomograms resulted in better performance for the estimation of DFS and OS than the clinicopathological nomograms and TNM staging system, with improved accuracy of the classification of survival outcomes. Further analysis showed that stage II and III patients with higher radiomics scores exhibited a favorable response to chemotherapy. In conclusion, the newly developed radiomics signature is a powerful predictor of DFS and OS, and it may predict which patients with stage II and III GC benefit from chemotherapy.
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- 2018
17. Preoperative histogram analysis of intravoxel incoherent motion (IVIM) for predicting microvascular invasion in patients with single hepatocellular carcinoma
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Yikai Xu, Zhongping Zhang, Maodong Chen, Yanqiu Feng, Yihao Guo, Hongxiang Li, Zeyu Zheng, Yingjie Mei, Jing Zhang, and Caiqin Xie
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Male ,Percentile ,Carcinoma, Hepatocellular ,Sensitivity and Specificity ,030218 nuclear medicine & medical imaging ,Motion ,03 medical and health sciences ,0302 clinical medicine ,Histogram ,Preoperative Care ,medicine ,Humans ,Effective diffusion coefficient ,Neoplasm Invasiveness ,Radiology, Nuclear Medicine and imaging ,Prospective Studies ,Intravoxel incoherent motion ,Retrospective Studies ,Receiver operating characteristic ,medicine.diagnostic_test ,business.industry ,Liver Neoplasms ,Magnetic resonance imaging ,General Medicine ,Middle Aged ,Magnetic Resonance Imaging ,Vascular Neoplasms ,Tumor Burden ,Diffusion Magnetic Resonance Imaging ,ROC Curve ,Area Under Curve ,030220 oncology & carcinogenesis ,Microvessels ,Kurtosis ,Female ,Tomography ,business ,Nuclear medicine - Abstract
Purpose To evaluate the value of intravoxel incoherent motion (IVIM) histogram analysis based on whole tumor volume in predicting microvascular invasion (MVI) of single hepatocellular carcinoma (HCC). Materials and Methods The study enrolled 41 patients with pathologically proven HCCs who underwent IVIM diffusion-weighted imaging with nine b values and contrast-enhanced magnetic resonance imaging (MRI). Histogram parameters including mean; skewness; kurtosis; and percentiles (5th, 10th, 25th, 50th, 75th, 90th, 95th) were derived from apparent diffusion coefficient (ADC), perfusion fraction (f), true diffusion coefficient (D), and pseudo diffusion coefficient (D*). Quantitative histogram parameters and clinical data were compared between HCCs with and without MVI. For significant parameters, receiver operating characteristic (ROC) curves were further plotted to compare the diagnosis performance for identifying MVI. Results The mean, 5th, 10th, 25th, 50th, and 75th percentiles of D, and the 5th, 10th, and 25th percentiles of ADC between HCCs with and without MVI were statistically significant (all P<0.05). The histogram parameters of D* and f showed no statistically significant differences between HCCs with and without MVI (all P>0.05). The areas under the ROC curves (AUCs) were 0.707–0.874 for D and 0.668–0.720 for ADC. The largest AUC of D (5th percentile) showed significantly higher accuracy than that of ADC or tumor size (P = 0.009–0.046). With a cut-off of 0.403 × 10−3 mm²/s, the 5th percentile of D value provided a sensitivity of 81% and a specificity of 85% in the prediction of MVI. Conclusions Histogram analysis of IVIM based on whole tumor volume can be useful for predicting MVI. The 5th percentile of D was most useful value to predict MVI of HCC.
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- 2018
18. Multifunctional NIR-responsive poly(vinylpyrrolidone)-Cu-Sb-S nanotheranostic agent for photoacoustic imaging and photothermal/photodynamic therapy
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Bingxia Zhao, Miaomiao Yuan, Meirong Hou, Qingliang Zhao, Yikai Xu, Zelong Chen, and Chenggong Yan
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Antimony ,Materials science ,Infrared Rays ,Chalcogenide ,medicine.medical_treatment ,Biomedical Engineering ,Photoacoustic imaging in biomedicine ,chemistry.chemical_element ,Nanoparticle ,Nanotechnology ,Photodynamic therapy ,02 engineering and technology ,Sulfides ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Theranostic Nanomedicine ,Nanomaterials ,Photoacoustic Techniques ,Biomaterials ,Mice ,chemistry.chemical_compound ,medicine ,Animals ,Humans ,Molecular Biology ,Mice, Inbred BALB C ,Povidone ,Hyperthermia, Induced ,Neoplasms, Experimental ,General Medicine ,Photothermal therapy ,021001 nanoscience & nanotechnology ,Copper ,0104 chemical sciences ,Photochemotherapy ,chemistry ,Nanoparticles ,Female ,0210 nano-technology ,Ternary operation ,HeLa Cells ,Biotechnology - Abstract
Ternary copper-based chalcogenide nanomaterials have become rather attractive due to the near-infrared (NIR) response in cancer theranostic fields. However, it is still challenging to further improve the theranostic efficiency of these nanomaterials. Herein, Cu-Sb-S nanoparticles (NPs) around 24 nm are synthesized facilely and functionalized with poly(vinylpyrrolidone) (PVP). Under the NIR irradiation, the resultant PVP-Cu-Sb-S NPs exhibit a relatively high photothermal conversion efficiency of 53.16% and a simultaneous reactive oxygen species (ROS) generation effect. Due to these outstanding photothermal/photodynamic effects, excellent tumor ablation results can be achieved by the combination of PVP-Cu-Sb-S NPs and 808 nm NIR laser treatments without obvious side effect. In addition, they show remarkable contrast enhancement according to in vitro and in vivo photoacoustic (PA) imaging. These PVP-Cu-Sb-S NPs could be served as a multifunctional nanotheranostic agent for PA imaging, photothermal/photodynamic cancer therapy. Statement of Significance Highly theranostic efficiency ternary copper-based chalcogenide nanomaterials has not been fully developed yet. Herein we report the PVP-Cu-Sb-S nanoparticles (NPs) with relatively high photothermal efficiency, simultaneous reactive oxygen species generation effect and photoacoustic imaging capability. The photothermal conversion efficiency of PVP-Cu-Sb-S NPs is higher than most of copper-based chalcogenide nanomaterials reported before. These findings provide a new kind of ternary copper-based chalcogenide with an enhanced theranostic effect, which could be served as a promising multifunctional nanotheranostic agent in the field of biomedical application.
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- 2018
19. Gd-EOB-DTPA-enhanced T1ρ imaging vs diffusion metrics for assessment liver inflammation and early stage fibrosis of nonalcoholic steatohepatitis in rabbits
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Jingting Chen, Chaoling Jin, Hongfeng Zhang, Yikai Xu, Xiang Wang, Yuanliang Xie, and Xiaoqi Wang
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Gadolinium DTPA ,Male ,medicine.medical_specialty ,Biomedical Engineering ,Biophysics ,Gastroenterology ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Non-alcoholic Fatty Liver Disease ,Fibrosis ,Internal medicine ,Animals ,Humans ,Medicine ,Effective diffusion coefficient ,Radiology, Nuclear Medicine and imaging ,Intravoxel incoherent motion ,Inflammation ,Receiver operating characteristic ,medicine.diagnostic_test ,business.industry ,Fatty liver ,Magnetic resonance imaging ,Image Enhancement ,medicine.disease ,Magnetic Resonance Imaging ,Disease Models, Animal ,Diffusion Magnetic Resonance Imaging ,Liver ,ROC Curve ,Area Under Curve ,Biomarker (medicine) ,030211 gastroenterology & hepatology ,Rabbits ,Steatohepatitis ,business - Abstract
To assess the value of T1ρ,T1ρ on hepatobiliary phase (HBP) and diffusion metrics in staging of Non-alcoholic fatty liver disease (NAFLD) activity scores, inflammation, fibrosis in NASH rabbits model. Non-alcoholic steatohepatitis (NASH) rabbits model was induced by feeding a varied duration of high-fat, high-cholesterol diet. T1ρ,T1ρ (HBP) 20min after administration of Gd-EOB-DTPA, and Intravoxel incoherent motion imaging (IVIM) diffusion-weighted imaging were performed on a 3.0T magnetic resonance (MR) imaging unit. The diagnostic value of each parameter for NAS, inflammation and fibrosis severity were determined. T1ρ (r=0.658) and T1ρ (HBP) (r=0.750) have strong association with NASH overall activity, T1ρ (HBP) is strongly relevant to inflammation stage (r=0.812). There was negative association between f and inflammation (r=-0.480), whilst no significant relation between other three parameters (apparent diffusion coefficient (ADC), pseudo-diffusion coefficient (D*) and true diffusion coefficient (D)) and inflammation or overall activity. The areas under the receiver operating characteristic curves (AUCs) of f, ADC, T1ρ and T1ρ-HBP were 0.871, 0.728, 0.849 and 0.949 for differentiating NASH; 0.731, 0.552, 0.925 and 0.922 for G2-3 inflammation; and 0.767, 0.625, 0.816, and 0.882 for S1-2 fibrosis. Comparison of ROC curve showed T1ρ (HBP) had an optimal diagnostic performance for NASH [T1ρ (HBP) vs ADC, AUC:0.949 vs 0.728, P=0.043], inflammation [T1ρ (HBP) vs ADC, AUC:0.922 vs 0.552, P=0.003], fibrosis [T1ρ (HBP) vs ADC, AUC:0.882 vs 0.625, P=0.046]. The combination of T1ρ (HBP)+perfusion fraction (f) showed highest diagnostic value for NASH (AUC:0.971), inflammation (AUC:0.935). Among T1ρ imaging and IVIM diffusion metrics, combination of T1rho (HBP)+f was found to be superior noninvasive imaging biomarker for NASH activity assessment.
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- 2018
20. Introducing Carbon Capture Science & Technology (CCST)!
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Chunfei Wu and Yikai Xu
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Environmental technology. Sanitary engineering ,TD1-1066 - Published
- 2021
21. Mitochondrial targeted fluorescent probe with AIE characteristics for bioimaging
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Qi Xia, Yikai Xu, Xiaodan Lu, Ruiyuan Liu, Meirong Hou, and Chenggong Yan
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Materials science ,Biocompatibility ,Mice, Nude ,Bioengineering ,Nanotechnology ,02 engineering and technology ,Mitochondrion ,010402 general chemistry ,01 natural sciences ,Biomaterials ,Mice ,chemistry.chemical_compound ,Optical imaging ,Animals ,Cytotoxicity ,Fluorescent Dyes ,Optical Imaging ,021001 nanoscience & nanotechnology ,Fluorescence ,Mitochondria ,0104 chemical sciences ,Solvent ,Benzothiazole ,chemistry ,Mechanics of Materials ,Solvents ,Biophysics ,0210 nano-technology ,Preclinical imaging - Abstract
In this work, a new benzothiazole based mitochondrial tracker, Bth-Mito, is synthesized by with 2-benzothiazoleacetonitrile and 4-(diethylamino)-benzaldehyde. Bth-Mito is weakly fluorescent when dissolved in the good solvent but becomes highly emissive in poor solvents, showing a phenomenon of aggregation-induced emission. Bth-Mito shows the greatest potentials for bioimaging applications in view of low cytotoxicity and high photostability. Bth-Mito could penetrate cells to give stable green fluorescence, even after continuous irradiation, making it suitable candidate for time-lapse and long-term bioimaging application. Moreover, Bth-Mito could specifically localize in mitochondrial. Furthermore, in vivo imaging studies on nude mice have revealed that Bth-Mito could be used as optical imaging probe for in vivo imaging. Histological assessment of tissues treated with Bth-Mito also further confirmed the low toxicity and good biocompatibility of Bth-Mito.
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- 2017
22. A novel fluorescence probe based on triphenylamine Schiff base for bioimaging and responding to pH and Fe 3+
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Yuping Zhou, Chenggong Yan, Xiuli Chen, Jinqing Qu, Lei Wang, Ruiyuan Liu, Xiaodong Yang, Yikai Xu, and Xiaodan Lu
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Aqueous solution ,Schiff base ,Analytical chemistry ,Bioengineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Triphenylamine ,Photochemistry ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,Biomaterials ,Job plot ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Intramolecular force ,Proton NMR ,Titration ,0210 nano-technology - Abstract
A novel fluorescence probe 1 based on triphenylamine was synthesized and characterized by NMR, IR, high resolution mass spectrometry and elemental analysis. Its fluorescence was quenched when pH below 2. There was a linear relationship between the fluorescence intensity and pH value ranged from 2 to 7. And its fluorescence emission was reversibility in acidic and alkaline solution. Furthermore, it exhibited remarkable selectivity and high sensitivity to Fe 3 + and was able to detect Fe 3 + in aqueous solution with low detection limit of 0.511 μM. Job plot showed that the binding stoichiometry of 1 with Fe 3 + was 1:1. Further observations of 1 H NMR titration suggested that coordination interaction between Fe 3 + and nitrogen atom on C N bond promoted the intramolecular charge transfer (ICT) or energy transfer process causing fluorescence quenching. Additionally, 1 was also able to be applied for detecting Fe 3 + in living cell and bioimaging.
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- 2017
23. Alterations of white matter structural networks in patients with non-neuropsychiatric systemic lupus erythematosus identified by probabilistic tractography and connectivity-based analyses
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Man Xu, Yanqiu Feng, Xinyuan Zhang, Yikai Xu, Yingjie Mei, Yihao Guo, Xiangliang Tan, and Qianjin Feng
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Adult ,Cognitive Neuroscience ,Central nervous system ,lcsh:Computer applications to medicine. Medical informatics ,lcsh:RC346-429 ,Probabilistic tractography ,White matter ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Lupus Erythematosus, Systemic ,Cingulum (brain) ,Radiology, Nuclear Medicine and imaging ,In patient ,lcsh:Neurology. Diseases of the nervous system ,Cerebral Cortex ,030203 arthritis & rheumatology ,business.industry ,Regular Article ,Graph theory ,Neuropsychiatric systemic lupus erythematosus ,Diffusion tensor imaging ,medicine.anatomical_structure ,Non-neuropsychiatric systemic lupus erythematosus ,Neurology ,lcsh:R858-859.7 ,Female ,Neurology (clinical) ,Nerve Net ,business ,Neuroscience ,Neurocognitive ,030217 neurology & neurosurgery ,Diffusion MRI - Abstract
Purpose Systemic lupus erythematosus (SLE) is a chronic inflammatory female-predominant autoimmune disease that can affect the central nervous system and exhibit neuropsychiatric symptoms. In SLE patients without neuropsychiatric symptoms (non-NPSLE), recent diffusion tensor imaging studies showed white matter abnormalities in their brains. The present study investigated the entire brain white matter structural connectivity in non-NPSLE patients by using probabilistic tractography and connectivity-based analyses. Methods Whole-brain structural networks of 29 non-NPSLE patients and 29 healthy controls (HCs) were examined. The structural networks were constructed with interregional probabilistic connectivity. Graph theory analysis was performed to investigate the topological properties, and network-based statistic was employed to assess the alterations of the interregional connections among non-NPSLE patients and controls. Results Compared with HCs, non-NPSLE patients demonstrated significantly decreased global and local network efficiencies and showed increased characteristic path length. This finding suggests that the global integration and local specialization were impaired. Moreover, the regional properties (nodal efficiency and degree) in the frontal, occipital, and cingulum regions of the non-NPSLE patients were significantly changed and negatively correlated with the disease activity index. The distribution pattern of the hubs measured by nodal degree was altered in the patient group. Finally, the non-NPSLE group exhibited decreased structural connectivity in the left median cingulate-centered component and increased connectivity in the left precuneus-centered component and right middle temporal lobe-centered component. Conclusion This study reveals an altered topological organization of white matter networks in non-NPSLE patients. Furthermore, this research provides new insights into the structural disruptions underlying the functional and neurocognitive deficits in non-NPSLE patients., Highlights • The global integration and local specialization of the white matter networks were disrupted in non-NPSLE patients. • The brain regions with significantly altered nodal properties were mainly involved in language, visual, and DMN systems. • The properties of some identified regions presented negative correlations with the SLE disease activity index scores. • The distribution pattern of the hubs measured by nodal degree was altered in the non-NPSLE patients. • The non-NPSLE group exhibited a subnetwork of decreased connectivity and a subnetwork of increased connectivity.
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- 2017
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24. Radiomic Nomogram for Prediction of Peritoneal Metastasis in Patients with Gastric Cancer
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Yikai Xu, Guoxin Li, Yanfeng Hu, Shi-Tong Yu, Zhiwei Zhou, Weicai Huang, Hao Liu, Ruoxiu Xiao, Chuanli Chen, Yuming Jiang, Jiang Yu, Zepang Sun, Qingyu Yuan, Jingjing Xie, Kangneng Zhou, and Zhen Han
- Subjects
Oncology ,medicine.medical_specialty ,Peritoneal metastasis ,business.industry ,Cancer ,Nomogram ,medicine.disease ,Logistic regression ,Radiomics ,Informed consent ,Internal medicine ,Cohort ,medicine ,In patient ,business - Abstract
Background: The aim of this study is to evaluate whether radiomic feature-based computed tomography (CT) imaging signatures could predict peritoneal metastasis (PM) in gastric cancer (GC) and to develop a preoperative nomogram for predicting PM status. Methods: We retrospectively analyzed radiomics features of CT images in 955 consecutive patients in pathological T4 gastric cancer from two cancer centers. The prediction model which was built from 292 quantitative image features was developed in the training cohort and validated in internal and external validation cohorts. Lasso regression model was used for feature selection and radiomics signature building. Predicting model was developed by multivariable logistic regression analysis. Radiomics signature, clinical T and N stage were incorporated and presented with a radiomics nomogram. We use calibration, discrimination, and clinical usefulness to assess the performance of the nomogram. Results: The radiomics signature was significantly associated with PM status in training and validation cohorts. Multivariable logistic analysis found the radiomics signature was an independent predictor for peritoneal metastasis. The discrimination accuracies of radiomic signature for predicting PM were 0.751(95%CI, 0.703-0.799), 0.802(95%CI, 0.691-0.912), and 0.745(95%CI, 0.683-0.806) for training cohort, internal and external validation cohort, respectively. Further, the discrimination accuracies of radiomic nomogram for predicting PM were 0.792(95%CI, 0.748-0.836), 0.870(95%CI, 0.795-0.946) and 0.815(95%CI, 0.763-0.867) for training cohort, internal and external validation cohort, respectively. Conclusions: CT-based radiomic signature was a powerful predictor of peritoneal metastasis and the radiomics nomogram could facilitate the preoperative individualized prediction of PM status. Funding Statement: This work was supported by grants from: National Natural Science Foundation of China 81672446, 81600510. The Outstanding Youths Development Scheme of Nanfang Hospital, Southern Medical University (2018J007). Director’s Foundation of Nanfang Hospital, 2016B010. Declaration of Interests: None of the authors had any potential conflicts of interest, including relevant financial interests, activities, relationships, and affiliations. Ethics Approval Statement: This study was approved by the ethics committee at every participating center, and the informed consent requirement was waived.
- Published
- 2019
25. The FTO m6A demethylase inhibits the invasion and migration of prostate cancer cells by regulating total m6A levels
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Ying Li, Yikai Xu, and Kai Zhu
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0301 basic medicine ,endocrine system diseases ,Biology ,Immunofluorescence ,medicine.disease_cause ,030226 pharmacology & pharmacy ,General Biochemistry, Genetics and Molecular Biology ,Metastasis ,03 medical and health sciences ,chemistry.chemical_compound ,Prostate cancer ,0302 clinical medicine ,medicine ,General Pharmacology, Toxicology and Pharmaceutics ,Cellular localization ,medicine.diagnostic_test ,nutritional and metabolic diseases ,pathological conditions, signs and symptoms ,General Medicine ,medicine.disease ,030104 developmental biology ,chemistry ,Cell culture ,Cancer research ,biology.protein ,Demethylase ,N6-Methyladenosine ,Carcinogenesis - Abstract
Aims N6-Methyladenosine (m6A) is the most frequent posttranscriptional modification and plays important roles in tumorigenesis and metastasis. The roles of fat mass and obesity-associated (FTO) in metabolic diseases have been widely explored. However, the molecular mechanisms and physiological functions of FTO in prostate cancer remain largely unknown. This study aimed to explore the exact functions of FTO in the progression of prostate cancer metastasis. Main methods Dot blot and m6A RNA methylation quantification assays were performed to determine m6A levels. The protein and mRNA expression levels were detected using immunoblot (IB) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analyses. Cell invasion and migration abilities were measured using transwell and wound healing assays. Bioinformatics was used to measure the expression level of FTO and possible correlation between FTO levels and advanced tumor stage. Immunofluorescence (IF) was performed to measure the cellular localization of FTO. Key findings FTO was downregulated in prostate cancer tissues and cell lines, and the m6A content was increased. Importantly, patients with lower FTO expression had advanced tumor stage and higher Gleason scores. Gain- and loss-of-function assays revealed that FTO inhibits prostate cancer cell invasion and migration in vitro. Moreover, we confirmed that FTO can decrease the total m6A level. Significance The present study revealed that the FTO m6A demethylase inhibits prostate cancer cell invasion and migration by regulating total m6A levels.
- Published
- 2021
26. Corrigendum to 'Noninvasive imaging evaluation of tumor immune microenvironment to predict outcomes in gastric cancer'
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Qingyu Yuan, Yikai Xu, Ruijiang Li, Hongxia Wang, Sujuan Xi, Yuming Jiang, Chuanli Chen, Yanfeng Hu, Weicai Huang, Tuanjie Li, Joseph C. Wu, Guoxin Li, and Zhiwei Zhou
- Subjects
Oncology ,Noninvasive imaging ,medicine.medical_specialty ,business.industry ,Immune microenvironment ,Internal medicine ,MEDLINE ,Medicine ,Cancer ,Hematology ,business ,medicine.disease - Published
- 2021
27. Waste plastics recycling for producing high-value carbon nanotubes: Investigation of the influence of Manganese content in Fe-based catalysts
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Yeshui Zhang, Steven E. J. Bell, Chunfei Wu, Su He, and Yikai Xu
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Environmental Engineering ,Materials science ,Hydrogen ,Health, Toxicology and Mutagenesis ,0211 other engineering and technologies ,chemistry.chemical_element ,02 engineering and technology ,Carbon nanotube ,Manganese ,010501 environmental sciences ,7. Clean energy ,01 natural sciences ,Catalysis ,law.invention ,law ,Environmental Chemistry ,Waste Management and Disposal ,0105 earth and related environmental sciences ,021110 strategic, defence & security studies ,Pollution ,Chemical engineering ,chemistry ,Yield (chemistry) ,Dispersion (chemistry) ,Pyrolysis ,Filamentous carbon - Abstract
Thermo-chemical conversion is a promising technology for the recycle of waste plastics, as it can produce high-value products such as carbon nanotubes (CNTs) and hydrogen. However, the low yield of CNTs is one of the challenges. In this work, the addition of Mn (0 wt.%, 1 wt.%, 5 wt.%, and 10 wt.%) to Fe-based catalyst to improve the production of CNTs has been investigated. Results show that the increase of Mn content from 0 wt.% to 10 wt.% significantly promotes CNTs yield formed on the catalyst from 23.4 wt.% to 32.9 wt.%. The results show that Fe-particles in the fresh catalysts are between 10−25 nm. And the addition of Mn in the Fe-based catalyst enhanced the metal-support interactions and the dispersion of metal particles, thus leading to the improved catalytic performance in relation to filamentous carbon growth. In addition, the graphitization of CNTs is promoted with the increase of Mn content. Overall, in terms of the quantity and quality of the produced CNTs, 5 wt.% of Mn in Fe-based catalyst shows the best catalytic performance, due to the further increase of Mn content from 5 wt.% to 10 wt.% led to a dramatic decrease of purity by 10 wt.%.
- Published
- 2021
28. Preparation and properties of organo-soluble tetraphenylethylene monolayer-protected gold nanorods
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Xiang Ma, Xuyang Yao, Tiantian Cao, Yikai Xu, and Dengfeng Li
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chemistry.chemical_classification ,Quenching (fluorescence) ,Process Chemistry and Technology ,General Chemical Engineering ,02 engineering and technology ,Tetraphenylethylene ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,Covalent bond ,Monolayer ,symbols ,Thiol ,Molecule ,Nanorod ,0210 nano-technology ,Raman spectroscopy - Abstract
Organo-soluble tetraphenylethylene derived monolayer-protected gold nanorods were prepared and characterized. The prepared gold nanorods covered with tetraphenylethylene thiol via the strong covalent Au–S linkage were found to be soluble and stable in organic solvents. The successful thiol exchange and modification of tetraphenylethylene derivative molecules on gold nanorods were confirmed from UV–Vis, Raman and FT-IR spectra. The gold nanorods were found to have a quenching effect on the aggregation-induced emission of the tetraphenylethylene thiol molecule modified on their surfaces.
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- 2016
29. Mitochondria-targeted aggregation-induced emission active near infrared fluorescent probe for real-time imaging
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Yikai Xu, Ruiyuan Liu, Xiaodan Lu, Chenggong Yan, Meirong Hou, Yanjing Dong, Zikang Chen, and Li Qi
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Biocompatibility ,Cell Survival ,Cytological Techniques ,Mice, Nude ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Analytical Chemistry ,Rhodamine ,Mice ,symbols.namesake ,chemistry.chemical_compound ,In vivo ,Stokes shift ,Organelle ,Animals ,Humans ,Tissue Distribution ,Instrumentation ,Spectroscopy ,Fluorescent Dyes ,Microscopy, Confocal ,Spectroscopy, Near-Infrared ,Quenching (fluorescence) ,Chemistry ,Near-infrared spectroscopy ,021001 nanoscience & nanotechnology ,Fluorescence ,Atomic and Molecular Physics, and Optics ,Mitochondria ,0104 chemical sciences ,symbols ,Biophysics ,Female ,0210 nano-technology ,HeLa Cells - Abstract
Mitochondria are essential organelles in eukaryotic cells and act as the energy powerhouse and biosynthetic compartment. Fluorescent dyes are widely used powerful molecular tools for analytical sensing and optical imaging. Low photostability, short excitation and emission wavelengths, and aggregation-induced quenching effects restrict the application of traditional commercial mitochondrial fluorescent probes for bioimaging. In this study, using rhodamine as the acceptor and phenothiazine as the donor, we synthesized a novel mitochondrial-targeted near infrared (NIR) fluorescent probe, MIT-PZR. Due to low cytotoxicity, great photostability and high specificity for mitochondria targeting, MIT-PZR has enormous potential for cell imaging. Furthermore, with a sizeable Stokes shift (emission peak at 705 nm), MIT-PZR penetrated tissues providing stable red fluorescence for imaging in vivo. The histological assessment of various tissues after treatment with MIT-PZR indicated that it has good biocompatibility. Thus, MIT-PZR is a promising mitochondrial NIR fluorescent probe for future application in clinical diagnosis and modern biological research.
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- 2020
30. Intravoxel incoherent motion diffusion-weighted MRI in patients with breast cancer: Correlation with tumor stroma characteristics
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Peng Hao, Yingman Zhao, Yikai Xu, Yuan Li, Xin Qin, Zhengping Wang, Yuankui Wu, Chang-Qing Li, Feng Chen, and Chenggong Yan
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Adult ,Contrast Media ,Breast Neoplasms ,030218 nuclear medicine & medical imaging ,Correlation ,Motion ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,Stroma ,Image Interpretation, Computer-Assisted ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,In patient ,Breast ,Prospective Studies ,Tumor stroma ,Intravoxel incoherent motion ,Tumor size ,business.industry ,Reproducibility of Results ,General Medicine ,Middle Aged ,medicine.disease ,Diffusion Magnetic Resonance Imaging ,030220 oncology & carcinogenesis ,Female ,Nuclear medicine ,business ,Diffusion MRI - Abstract
Purpose To determine whether imaging parameters derived from intravoxel incoherent motion (IVIM) diffusion weighted imaging (DWI) vary according to tumor-stroma ratio(TSR) or dominant stroma type of breast cancer. Methods We prospectively enrolled 77 patients with breast cancer who underwent IVIM DWI on a 3.0 T MR scanner. The values of IVIM parameters (D, D* and f) were measured. After surgery, TSR or dominant stroma type was evaluated. The relationship between imaging parameters and tumor stroma characteristics was analyzed. Results The mean D and f values were lower in stroma-poor tumor than in stroma-rich tumor (P = 0.012, 0.015). The mean D value was lower in the collagen-dominant type than in fibroblast-dominant or lymphocyte-dominant type (P = 0.032, 0.043). According to multivariate linear regression analyses, tumor size (P = 0.007), TSR (P = 0.008), dominant stroma type (collagen dominant, P = 0.012), and histological grade (P = 0.031) were independently correlated with D value; and tumor size (P = 0.011), TSR (P = 0.021) and histological grade (P = 0.037) were independently correlated with f value. Conclusion In breast cancer, D and f values show significant differences according to TSR, and D value is lower in collagen dominant type than in fibroblast dominant or lymphocyte dominant types.
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- 2019
31. Radiomic Signature of Computed Tomography Imaging for Prediction of Survival and Chemotherapeutic Benefits in Gastric Cancer
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Tuanjie Li, Wei Wang, Xuefan Zha, Jingjing Xie, Guoxin Li, Yanfeng Hu, Yikai Xu, Chuanli Chen, Zhiwei Zhou, Jiang Yu, Wenbing Lv, and Yuming Jiang
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National health ,medicine.medical_specialty ,Multivariate analysis ,medicine.diagnostic_test ,business.industry ,External validation ,Cancer ,Computed tomography ,TNM staging system ,Nomogram ,Stage ii ,medicine.disease ,Medicine ,Medical physics ,business - Abstract
To develop and validate a radiomics signature for prediction of gastric cancer (GC) survival and chemotherapeutic benefits. In this multicenter retrospective analysis, we analyzed radiomics features of portal venous-phase computed tomography in 1,591 consecutive patients. A radiomics signature was generated by using the Lasso-Cox regression model in 228 patients and validated in internal and external validation cohorts. Radiomics nomograms integrating the radiomics signature were constructed, demonstrating the incremental value of the radiomics signature to the traditional staging system for individualized survival estimation. The performance of the nomograms was assessed with respect to calibration, discrimination, and clinical usefulness. The radiomics signature consisted of 19 selected features and was significantly associated with DFS and OS. Multivariate analysis demonstrated that the radiomics signature was an independent prognostic factor. Incorporating the radiomics signature into the radiomics-based nomograms resulted in better performance for the estimation of DFS than the clinicopathologic nomograms and the TNM staging system, with improved accuracy of the classification of survival outcomes. Further analysis showed stage II and III patients with higher radiomics scores exhibited a favorable response to chemotherapy. In conclusion, the newly developed radiomics signature was a powerful predictor of OS and DFS. Moreover, the radiomics signature could predict which patients with stage II and III GC benefit from chemotherapy. Funding Statement: This work was supported by grants from: National Natural Science Foundation of China 81672446, 81600510, 81370575, 81570593. Natural Science Foundation of Guangdong Province, 2014A030313131. Science and Technology Planning Project of Guangzhou, 2014B020228003, 2014B030301041, 2015A030312013. Science and Technology Program of Guangzhou, 158100076, 201400000001-3. Public welfare in Health Industry, National Health and Family Planning Commission of China (201402015, 201502039). Key Clinical Specialty Discipline Construction Program. Declaration of Interests: The author(s) indicated no potential conflicts of interest. Ethics Approval Statement: Ethical approval was obtained for this retrospective analysis at every participating center, and the informed consent requirement was waved.
- Published
- 2018
32. The risk of placental abruption and placenta previa in pregnant women with chronic hepatitis B viral infection: A systematic review and meta-analysis
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Q.T. Huang, Li-lin Hang, Y.H. Yu, Mei Zhong, Yikai Xu, Q. Liu, C.X. Cai, Shan-shan Wei, and Jianing Chen
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medicine.medical_specialty ,Placental abruption ,Obstetrics ,business.industry ,Placenta Previa ,Obstetrics and Gynecology ,medicine.disease ,Viral infection ,Placenta previa ,Hepatitis B, Chronic ,Reproductive Medicine ,Chronic hepatitis ,Pregnancy ,Meta-analysis ,Relative risk ,Epidemiology ,medicine ,Humans ,Female ,Electronic database ,Pregnancy Complications, Infectious ,business ,Abruptio Placentae ,Developmental Biology - Abstract
Introduction Several epidemiological studies have found a positive association between chronic hepatitis B virus (CHB) infection and the risk of placental abruption and placenta previa, but various studies have reported conflicting findings. The objective was to systematically review the literature to determine a possible association between CHB infection and these two placental complications. Methods We conducted a computerized search in electronic database through March 1, 2014, supplemented with a manual search of reference lists, to identify original published research on placental abruption and placenta previa rates in women with CHB infection. Data were independently extracted, and relative risks were calculated. The meta-analysis was performed using Stata version 10.0 software. Results Five studies involving 9088 placenta previa cases were identified. No significant association between CHB infection and placenta previa was identified (OR = 0.98, 95% CI = 0.60–1.62). Five studies involving 15571 placental abruption cases were identified. No significant association between CHB infection and placental abruption was identified (OR = 1.42, 95% CI, 0.93–2.15). Discussion The immune response against the virus represents a key factor in determining infection outcomes. No observation of significant increased risk of the placental complications could be partially explained by the complex immune response during CHB infection. Conclusions Our meta-analysis found no evidence of significant associations between CHB infection and increased risk of placental abruption as well as placenta previa. Further well-designed studies were warranted to assess any potential association between CHB infection and increased risk of placental abruption as well as placenta previa.
- Published
- 2014
33. Optimal region-of-interest MRI R2* measurements for the assessment of hepatic iron content in thalassaemia major
- Author
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Xinyuan Zhang, Meiyan Feng, Huashuai Gao, Binquan Lin, Wufan Chen, Yikai Xu, Yanqiu Feng, and Jianyun Liao
- Subjects
Adult ,Male ,Accuracy and precision ,Iron ,Biomedical Engineering ,Biophysics ,Signal-To-Noise Ratio ,Region of interest ,Image Interpretation, Computer-Assisted ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Hepatic iron ,Retrospective Studies ,Mathematics ,Reproducibility ,medicine.diagnostic_test ,Thalassaemia major ,business.industry ,beta-Thalassemia ,Reproducibility of Results ,Magnetic resonance imaging ,Magnetic Resonance Imaging ,Noise ,Liver ,Content (measure theory) ,Female ,Nuclear medicine ,business ,Algorithms - Abstract
Objectives To evaluate the performance of region-of-interest (ROI)-based MRI R2* measurements by using the first-moment noise-corrected model (M1NCM) to correct the non-central Chi noise in magnitude images from phased arrays for hepatic iron content (HIC) assessment. Methods R2* values were quantified using the M1NCM model. Three approaches were employed to determine the representative R2*: fitting of the ROI-averaged signal (average-then-fit, ATF); outputting the median and mean of R2*s from the pixel-wise fitting of decay signals within the ROI (denoted as PWFmed and PWFmea, respectively). The accuracy and precision of the three approaches were evaluated on synthesized data. The agreement among these approaches and their intra- and inter-observer reproducibility were assessed on 105 thalassaemia major patients. Results Simulations showed that ATF consistently yielded the highest accuracy and precision at varying noise levels. By contrast, PWFmed and PWFmea slightly and significantly overestimated high R2* at poor signal-to-noise ratios, respectively. Patient study showed that ATF agreed well with PWFmed, whereas PWFmea produced high R2* measurements for patients with severe HIC. No significant difference was observed in the reproducibility of the three approaches. Conclusions PWFmea tends to overestimate high R2*, whereas ATF and PWFmed can produce more accurate R2* measurements for HIC assessment.
- Published
- 2014
34. Early identification of neonatal mild hypoxic-ischemic encephalopathy by amide proton transfer magnetic resonance imaging: A pilot study
- Author
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Yingjie Mei, Caixia Li, Sijin Chen, Xilong Liu, Daokun Ren, Mei Zhong, and Yikai Xu
- Subjects
Male ,Encephalopathy ,Ischemia ,Gestational Age ,Pilot Projects ,Risk Assessment ,Hypoxic Ischemic Encephalopathy ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Thalamus ,Centrum semiovale ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Child ,medicine.diagnostic_test ,business.industry ,Putamen ,Infant, Newborn ,Brain ,Gestational age ,Magnetic resonance imaging ,General Medicine ,medicine.disease ,Amides ,Magnetic Resonance Imaging ,Postnatal age ,Early Diagnosis ,Case-Control Studies ,030220 oncology & carcinogenesis ,Hypoxia-Ischemia, Brain ,Feasibility Studies ,Female ,Protons ,business ,Nuclear medicine - Abstract
This study aimed to evaluate the amide proton transfer (APT) values in neonates with mild hypoxic-ischemic encephalopathy (HIE) using APT imaging.A total of 30 full-term neonates with mild HIE (16 males and 14 females; mean postnatal age 4.2 days, age range 2-7 days) and 12 normal neonates (six males and six females; mean postnatal age 3.3 days, age range 2-5 days) underwent conventional magnetic resonance imaging and APT imaging. APT measurements were performed in multiple regions of interest (ROIs) in the brain. APT values were statistically analyzed to assess for significant differences between the mild HIE and normal neonates in different regions of the brain, and correlation with neonatal gestational age.In 30 neonates with mild HIE, 10% (3/30) of the HIE patients had normal conventional MRI. There were significant differences in APT values of the HIE group in bilateral caudate, bilateral thalamus, bilateral centrum semiovale and left globus pallidus/putamen (p 0.05), and no statistical difference was observed in right globus pallidus/putamen (p = 0.051) and brainstem (p = 0.073) between the two groups. Furthermore, APT values in bilateral caudate, bilateral globus pallidus/putamen, bilateral thalamus, and brainstem regions (p 0.05) exhibited positive linear correlations with gestational age in the control group, except for bilateral centrum semiovale (right: Pearson's r = 0.554, p = 0.062; left: Pearson's r = 0.561, p = 0.058). In the mild HIE groups, no significant correlation with gestational age was found in all regions.APT imaging is a feasible and useful technique with diagnostic capability for neonatal HIE.
- Published
- 2019
35. Detection of hypoxic-ischemic brain injury with 3D-enhanced T2* weighted angiography (ESWAN) imaging
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Jia-Ning Zhang, Peng Hao, Yikai Xu, and Qiang-Qiang Gang
- Subjects
Pathology ,medicine.medical_specialty ,Swine ,Thalamus ,Encephalopathy ,Contrast Media ,Hypoxic ischemic brain injury ,Striatum ,Sensitivity and Specificity ,Imaging, Three-Dimensional ,Image Interpretation, Computer-Assisted ,medicine ,Animals ,Humans ,Radiology, Nuclear Medicine and imaging ,medicine.diagnostic_test ,business.industry ,Reproducibility of Results ,Magnetic resonance imaging ,General Medicine ,Image Enhancement ,medicine.disease ,Disease Models, Animal ,Animals, Newborn ,Brain Injuries ,Hypoxia-Ischemia, Brain ,Angiography ,Swine, Miniature ,Immunohistochemistry ,T2 weighted ,business ,Magnetic Resonance Angiography - Abstract
Objective To demonstrate the use of 3D-enhanced T2* weighted angiography (ESWAN) imaging for the observation and quantification of the evolution of brain injury induced by a recently developed model of hypoxic-ischemic brain injury (HI/R) in neonatal piglets. Methods For these experiments, newborn piglets were subjected to HI/R injury, during which ESWAN scanning was performed, followed by H&E staining and immunohistochemistry of AQP-4 expression. Results In the striatum, values from T2* weighted magnetic resonance imaging (MRI) increased and reached their highest level at 3 days post injury, whereas T2* values increased and peaked at 24 h in the subcortical region. The change in T2* values was concordant with brain edema. Phase values in the subcortical border region were not dependent on time post-injury. Magnitude values were significantly different from the control group, and increased gradually over time in the subcortical border region. Susceptibility-weighted images (SWI) indicated small petechial hemorrhages in the striatum and thalamus, as well as dilated intramedullary veins. Conclusion SWI images can be used to detect white and gray matter microhemorrhages and dilated intramedullary veins. The T2*, phase, and magnitude map can also reflect the development of brain injury. Our data illustrate that ESWAN imaging can increase the diagnostic sensitivity and specificity of MRI in neonatal hypoxic-ischemic encephalopathy.
- Published
- 2013
36. Distribution of intravoxel incoherent motion MRI-related parameters in the brain: evidence of interhemispheric asymmetry
- Author
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Yihao Guo, Chunhong Wang, D. Ren, Yikai Xu, Yanqiu Feng, Xiaoyong Zhang, Yingjie Mei, Maodong Chen, and X. Xiao
- Subjects
Adult ,Grey matter ,Sensitivity and Specificity ,030218 nuclear medicine & medical imaging ,Temporal lobe ,White matter ,Motion ,03 medical and health sciences ,Imaging, Three-Dimensional ,0302 clinical medicine ,Nuclear magnetic resonance ,Image Interpretation, Computer-Assisted ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Cerebrum ,Intravoxel incoherent motion ,Evidence-Based Medicine ,medicine.diagnostic_test ,business.industry ,Reproducibility of Results ,Magnetic resonance imaging ,General Medicine ,Image Enhancement ,White Matter ,Lobe ,Diffusion Tensor Imaging ,medicine.anatomical_structure ,Frontal lobe ,business ,030217 neurology & neurosurgery ,Diffusion MRI - Abstract
Aim To compare intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI)-derived true diffusion (D) and perfusion fraction (f)-values of the two hemispheres to detect the presence of asymmetrical differences. Materials and methods Forty-seven healthy right-handed volunteers were assessed using IVIM imaging. The interhemispheric D- and f-values were compared using paired t-tests and two related-samples Wilcoxon's test. Results Comparison of the interhemispheric D- and f-values of the grey matter revealed a significant difference in the D-value of the frontal lobe and the f-value of the temporal lobe (p=0.028, p=0.030, respectively). A significant difference in the D-values of the frontal, temporal, and occipital lobes (p=0.003, p=0.005, and p=0.001, respectively) was seen, whereas no significant difference in f-values was seen. Conclusions The distribution of the IVIM-derived D- and f-values in the two hemispheres was not completely symmetrical. Radiologists should consider this difference when the contralateral region is used as internal reference to normalise the IVIM imaging results. Average values of the interhemispheric white matter within the same lobe as the lesion may be the best internal reference.
- Published
- 2017
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