Can Machine Learning Models Based on Computed Tomography Radiomics and Clinical Characteristics Provide Diagnostic Value for Epstein-Barr Virus-Associated Gastric Cancer?

OBJECTIVE: The aim of this study was to explore whether machine learning model based on computed tomography (CT) radiomics and clinical characteristics can differentiate Epstein-Barr virus-associated gastric cancer (EBVaGC) from non-EBVaGC. METHODS: Contrast-enhanced CT images were collected from 158 patients with GC (46 EBV-positive, 112 EBV-negative) between April 2018 and February 2023. Radiomics features were extracted from the volumes of interest. A radiomics signature was built based on radiomics features by the least absolute shrinkage and selection operator logistic regression algorithm. Multivariate analyses were used to identify significant clinicoradiological variables. We developed 6 ML models for EBVaGC, including logistic regression, Extreme Gradient Boosting, random forest (RF), support vector machine, Gaussian Naive Bayes, and K-nearest neighbor algorithm. The area under the receiver operating characteristic curve (AUC), the area under the precision-recall curves (AP), calibration plots, and decision curve analysis were applied to assess the effectiveness of each model. RESULTS: Six ML models achieved AUC of 0.706-0.854 and AP of 0.480-0.793 for predicting EBV status in GC. With an AUC of 0.854 and an AP of 0.793, the RF model performed the best. The forest plot of the AUC score revealed that the RF model had the most stable performance, with a standard deviation of 0.003 for AUC score. RF also performed well in the testing dataset, with an AUC of 0.832 (95% confidence interval: 0.679-0.951), accuracy of 0.833, sensitivity of 0.857, and specificity of 0.824, respectively. CONCLUSIONS: The RF model based on clinical variables and Rad_score can serve as a noninvasive tool to evaluate the EBV status of gastric cancer.

Inflammation Disrupts the Brain Network of Executive Function after Cardiac Surgery.

OBJECTIVE: To investigate postoperative functional connectivity (FC) alterations across impaired cognitive domains and their causal relationships with systemic inflammation. BACKGROUND: Postoperative cognitive dysfunction commonly occurs after cardiac surgery, and both systemic and neuroinflammation may trigger its development. Whether FC alterations underlying deficits in specific cognitive domains after cardiac surgery are affected by inflammation remains unclear. METHODS: Seventeen patients, who underwent cardiac valve replacement, completed a neuropsychological test battery and brain MRI scan before surgery and on days 7 and 30 after surgery compared to age-matched healthy controls. Blood samples were taken for tumor necrosis factor-a and interleukin-6 measurements. Seed-to-voxel FC of the left dorsolateral prefrontal cortex (DLPFC) was examined. Bivariate correlation and linear regression models were used to determine the relationships among cognitive function, FC alterations, and cytokines. RESULTS: Executive function was significantly impaired after cardiac surgery. At day 7 follow-up, the surgical patients, compared to the controls, demonstrated significantly decreased DLPFC FC with the superior parietal lobe and attenuated negative connectivity in the default mode network, including the angular gyrus and posterior cingulate cortex. The left DLPFC enhanced the connectivity in the right DLPFC and posterior cingulate cortex, all of which were related to the increased tumor necrosis factor-a and decreased executive function up to day 7 after cardiac surgery. CONCLUSIONS: The decreased FC of executive control network and its anticorrelation with the default mode network may contribute to executive function deficits after cardiac surgery. Systemic inflammation may trigger these transient FC changes and executive function impairments.

A chemoenzymatic process for preparation of highly purified dehydroepiandrosterone in high space-time yield.

Dehydroepiandrosterone (DHEA) is an important neurosteroid hormone to keep human hormonal balance and reproductive health. However, DHEA was always produced with impurities either by chemical or biological method and required high-cost purification before the medical use. To address this issue, a novel chemoenzymatic process was proposed and implemented to produce DHEA. An acetoxylated derivate of 4-androstene-3,17-dione (4-AD) was generated by chemical reaction and converted into DHEA by an enzyme cascade reaction combining a hydrolysis reaction with a reduction reaction. The hydrolysis reaction was catalyzed by a commercial esterase Z03 while the reduction reaction was catalyzed by E. coli cells co-expressing a 3ß-hydroxysteroid dehydrogenase SfSDR and a glucose dehydrogenase BtGDH. After the condition optimization, DHEA was synthesized at a 100 mL scale under 100 mM of substrate loading and purified as white powder with the highest space-time yield (4.80 g/L/h) and purity (99 %) in the biosynthesis of DHEA. The successful attempt in this study provides a new approach for green synthesis of highly purified DHEA in the pharmaceutical industry.

Radiomics nomogram based on optimal VOI of multi-sequence MRI for predicting microvascular invasion in intrahepatic cholangiocarcinoma.

OBJECTIVE: Microvascular invasion (MVI) is a significant adverse prognostic indicator of intrahepatic cholangiocarcinoma (ICC) and affects the selection of individualized treatment regimens. This study sought to establish a radiomics nomogram based on the optimal VOI of multi-sequence MRI for predicting MVI in ICC tumors. METHODS: 160 single ICC lesions with MRI scanning confirmed by postoperative pathology were randomly separated into training and validation cohorts (TC and VC). Multivariate analysis identified independent clinical and imaging MVI predictors. Radiomics features were obtained from images of 6 MRI sequences at 4 different VOIs. The least absolute shrinkage and selection operator algorithm was performed to enable the derivation of robust and effective radiomics features. Then, the best three sequences and the optimal VOI were obtained through comparison. The MVI prediction nomogram combined the independent predictors and optimal radiomics features, and its performance was evaluated via the receiver operating characteristics, calibration, and decision curves. RESULTS: Tumor size and intrahepatic ductal dilatation are independent MVI predictors. Radiomics features extracted from the best three sequences (T1WI-D, T1WI, DWI) with VOI10mm (including tumor and 10 mm peritumoral region) showed the best predictive performance, with AUCTC = 0.987 and AUCVC = 0.859. The MVI prediction nomogram obtained excellent prediction efficacy in both TC (AUC = 0.995, 95%CI 0.987-1.000) and VC (AUC = 0.867, 95%CI 0.798-0.921) and its clinical significance was further confirmed by the decision curves. CONCLUSION: A nomogram combining tumor size, intrahepatic ductal dilatation, and the radiomics model of MRI multi-sequence fusion at VOI10mm may be a predictor of preoperative MVI status in ICC patients.

Comparison of the effectiveness of anchoring needles and coils in localizing multiple nodules in the lung.

BACKGROUND: Recently, a new type of pulmonary nodule positioning needle has been adopted clinically. We aimed to evaluate the efficacy and safety of a new type of localization needles compared with coils for the simultaneous localization of multiple pulmonary nodules guided by computed tomography (CT) prior to video-assisted thoracoscopic surgery (VATS). MATERIALS AND METHODS: From January 2021 to March 2022, 87 pulmonary nodules from 40 patients were localized using the new localization needle. From January 2020 to December 2020, 68 pulmonary nodules in 31 patients were localized using coils. The relative outcomes were compared. RESULTS: The success rate of pulmonary nodule localization in the needle group was 97.7% while that in the coil group was 98.5%. In the needle group, the time needed to locate the first nodule was significantly shorter than in the coil group (10.9 min vs. 17.2 min, P = 0.001). Moreover, the time needed per patient was also significantly shorter for the needle group compared with the coil group (23.7 min vs. 30 min, P = 0.017). The incidence of pneumothorax in the needle group was 25.0% vs. 12.9% in the coil group (P = 0.204). The rate of pulmonary hemorrhage in the needle group was 40.0% vs. 32.3% in the coil group (P = 0.502). The success rate of VATS wedge resection was 100% in both groups. CONCLUSION: Both disposable pulmonary nodule localization needles and coils are safe and effective for CT-guided localization of multiple pulmonary nodules of the same stage prior to VATS. However, the use of needles is time-saving compared with the use of coils. The coil localization may exhibit better safety than needle localization.

Preoperative computed tomography-guided localization for lung nodules: localization needle versus coil.

PURPOSE: To compare the clinical efficacy of computed tomography (CT)-guided localization needle and coil insertion as approaches to preoperative lung nodule (LN) localization. MATERIAL AND METHODS: Between January 2018 and December 2019, 52 patients awaiting video-assisted thoracoscopic surgery (VATS) resection underwent CT-guided coil insertion to facilitate LN localization. Additionally, 41 patients underwent CT-guided localization needle insertion between January and June 2021. RESULTS: In total, 62 and 54 LNs were localized in 52 and 41 patients in the coil and localization needle groups, respectively, with respective technical localization success rates of 96.8% and 100% (p = .498). The localization needle group exhibited a significantly shorter duration of localization relative to the coil group (p < .001), whereas comparable rates of pneumothorax (p = .918) and hemorrhage (p = .712) were evident in these groups. VATS-guided LN resection procedures achieved 100% technical success rates in both groups, and there were no significant differences between groups with respect to the type of resection (p = .113) or the mean duration of VATS (p = .778). CONCLUSION: Coil- and localization needle-based approaches can be successfully used for LN localization prior to VATS resection, with localization needle insertion being associated with a shorter duration of localization.

I-125 seeds insertion with TACE for advanced HCC: a meta-analysis of randomized controlled trials.

PURPOSE: To assess the effectiveness of I-125 seeds (IS) insertion with transcatheter arterial chemoembolization (TACE) in treating patients with advanced hepatocellular carcinoma (HCC). MATERIAL AND METHODS: An extensive search was conducted for relevant randomized controlled trials (RCTs) from the establishment date of each database to November 2020. RESULTS: A total of nine RCTs were included in this study. Our analysis showed no significant changes in the pooled Δalpha-fetoprotein values (p = .06), incident rates of myelosuppression (p = .46), vomit occurrence (p = .27), and abnormal liver function (p = .42) between the two treatment groups. However, the complete response (p < .00001), total response (p < .00001), and disease control (p < .00001) rates were significantly higher in patients who underwent TACE with IS insertion, as opposed to patients who received TACE alone. Furthermore, patients who underwent TACE with IS insertion experienced markedly longer pooled overall survival (OS) time (p < .0001), with better OS rates at the six-month (p = .0002), one-year (p < .0001), and three-year (p = .0003) follow-ups than patients who received TACE alone. CONCLUSION: TACE with IS insertion can significantly improve clinical response and prolong the survival of advanced HCC patients.

Association of Hypertension With Both Occurrence and Outcome of Symptomatic Patients With Mild Intracranial Atherosclerotic Stenosis: A Prospective Higher Resolution Magnetic Resonance Imaging Study.

BACKGROUND: Intracranial atherosclerotic plaque causing mild luminal stenosis might lead to acute ischemic events. However, the difference between culprit and nonculprit lesions is unclear, as are the factors associated with favorable treatment outcomes. PURPOSE: To quantify characteristics of intracranial atherosclerosis with mild luminal stenosis and to identify factors associated with lesion type (culprit or nonculprit) and with clinical outcomes. STUDY TYPE: Prospective POPULATION: 293 patients who had acute stroke with mild luminal stenosis (<50%) in the middle cerebral or basilar artery. FIELD STRENGTH/SEQUENCE: 3.0 T higher resolution magnetic resonance imaging (hrMRI) of intracranial arteries and whole brain MR images. ASSESSMENT: Morphological and compositional analysis of plaques was performed. This included assessment of plaque volume, plaque burden, remodeling ratio, eccentricity, intraplaque hemorrhage, and enhancement ratio. Clinical outcomes were assessed according to the modified Rankin Scale (mRS) at day 90, with a favorable outcome being defined as a 90-day mRS ≤2. STATISTICAL TESTS: The odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by a logistic regression model. RESULTS: Hypertension (OR 5.2; 95% CI 2.6-10.3; P < 0.05) and hrMRI enhancement ratio (OR 2.7; 95% CI 1.4-5.1; P < 0.05) were independently associated with lesion type. Patients without hypertension had significantly more (P < 0.05) favorable outcomes (124/144) than patients with hypertension (97/149). Most hypertensive patients without any previous blood pressure control (54/63) had a favorable outcome. However, these patients were significantly younger (P < 0.05) than those with adequate blood pressure control. After adjusting for all significant characteristics, hypertension duration (OR 1.19; 95% CI 1.09-1.29; P < 0.05), hypertension management (OR 2.49; 95% CI 1.18-5.26; P < 0.05), and enhancement ratio (OR 0.01; 95% CI 0.001-0.157; P < 0.05) were found to be independent high-risk factors for outcome prediction. DATA CONCLUSION: hrMRI provided incremental value over traditional risk factors in identifying higher risk intracranial atherosclerosis with mild luminal stenosis. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.

Clinical-radiological predictive model in differential diagnosis of small (≤ 20 mm) solitary pulmonary nodules.

BACKGROUND: There is a lack of clinical-radiological predictive models for the small (≤ 20 mm) solitary pulmonary nodules (SPNs). We aim to establish a clinical-radiological predictive model for differentiating malignant and benign small SPNs. MATERIALS AND METHODS: Between January 2013 and December 2018, a retrospective cohort of 250 patients with small SPNs was used to construct the predictive model. A second retrospective cohort of 101 patients treated between January 2019 and December 2020 was used to independently test the model. The model was also compared to two other models that had previously been identified. RESULTS: In the training group, 250 patients with small SPNs including 156 (62.4%) malignant SPNs and 94 (37.6%) benign SPNs patients were included. Multivariate logistic regression analysis indicated that older age, pleural retraction sign, CT bronchus sign, and higher CEA level were the risk factors of malignant small SPNs. The predictive model was established as: X = - 10.111 + [0.129 × age (y)] + [1.214 × pleural retraction sign (present = 1; no present = 0)] + [0.985 × CT bronchus sign (present = 1; no present = 0)] + [0.21 × CEA level (ug/L)]. Our model had a significantly higher region under the receiver operating characteristic (ROC) curve (0.870; 50% CI: 0.828-0.913) than the other two models. CONCLUSIONS: We established and validated a predictive model for estimating the pre-test probability of malignant small SPNs, that can help physicians to choose and interpret the outcomes of subsequent diagnostic tests.

Computed tomography-guided cryoablation for functional adrenal aldosteronoma.

PURPOSE: To assess the safety and clinical effectiveness of computed tomography (CT)-guided cryoablation for functional adrenal aldosteronoma. MATERIAL AND METHODS: From June 2012 to December 2018, 11 patients with functional adrenal aldosteronoma underwent CT-guided cryoablation in our center. Data comprising complete ablation rate, clinical success rate, procedure-related complications and long-term outcome were collected and analyzed. RESULTS: A total of 11 aldosteronoma in 11 patients were treated. Complete ablation was achieved in all patients after a single ablation session. No procedure-related complications occurred. Clinical success rate was 100%. Mean aldosterone levels, and systolic and diastolic pressure decreased from 858.6 ± 93.2 pmol/L, 156.4 ± 7.8 mmHg and 90.0 ± 10.5 mmHg prior to treatment, respectively, to 321.8 ± 41.2 pmol/L (p < .001), 129.1 ± 9.4 mmHg (p < .001) and 76.4 ± 5.5 mmHg (p = .005) after treatment, respectively. Mean renin and potassium improved from 0.2 ± 0.1 µg/L/h and 2.9 ± 0.2 mmol/L before treatment, respectively to 4.6 ± 0.4 µg/L/h (p < .001) and 4.2 ± 0.2 mmol/L (p < .001) following treatment, respectively. No tumor or clinical symptom recurrence occurred during the follow-up. CONCLUSIONS: CT-guided cryoablation is a safe and effective method for the treatment of functional adrenal aldosteronoma.

Computed tomography-guided lung biopsy: a randomized controlled trial of low-dose versus standard-dose protocol.

OBJECTIVES: To assess the relative diagnostic utility of low- and standard-dose computed tomography (CT)-guided lung biopsy. METHODS: In this single-center, single-blind, prospective, randomized controlled trial, patients were enrolled between November 2016 and June 2017. Enrolled study participants were randomly selected to undergo either low- or standard-dose CT-guided lung biopsy. Diagnostic accuracy was the primary study endpoint, whereas technical success, radiation dose, and associated complications were secondary study endpoints. RESULTS: In total, 280 patients underwent study enrollment and randomization, with 271 (low-dose group, 135; standard-dose group, 136) receiving the assigned interventions. Both groups had a 100% technical success rate for CT-guided lung biopsy, and complication rates were similar between groups (p > 0.05). The mean dose-length product (36.0 ± 14.1 mGy cm vs. 361.8 ± 108.0 mGy cm, p < 0.001) and effective dose (0.5 ± 0.2 mSv vs. 5.1 ± 1.5 mSv, p < 0.001) were significantly reduced in the low-dose group participants. Sensitivity, specificity, and overall diagnostic accuracy rates in the low-dose group were 91.8%, 100%, and 94.6%, respectively, whereas in the standard-dose group, the corresponding values were 89.6%, 100%, and 92.4%, respectively. These results indicated that diagnostic performance did not differ significantly between the 2 groups. Using univariate and multivariate analyses, we found larger lesion size (p = 0.038) and procedure-related pneumothorax (p = 0.033) to both be independent predictors of diagnostic failure. CONCLUSIONS: Our results demonstrate that low-dose CT-guided lung biopsy can yield comparable diagnostic accuracy to standard-dose CT guidance, while significantly reducing the radiation dose delivered to patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT02971176 KEY POINTS: • Low-dose CT-guided lung biopsy is a safe and simple method for diagnosis of lung lesions. • Low-dose CT-guided lung biopsy can yield comparable diagnostic accuracy to standard-dose CT guidance. • Low-dose CT-guided lung biopsy can achieve a 90% reduction in radiation exposure when compared with standard-dose CT guidance.

Computed Tomography Fluoroscopy-Guided Versus Conventional Computed Tomography-Guided Lung Biopsy: A Systematic Review and Meta-analysis.

PURPOSE: This study aimed to compare the feasibility, safety, diagnostic accuracy, and radiation dose between computed tomography (CT) fluoroscopy (CTF)-guided and conventional CT (CCT)-guided lung biopsy. METHODS: Relevant articles up until February 2020 were identified within the PubMed, Embase, and Cochrane Library databases. Diagnostic accuracy rate, pneumothorax, and pneumothorax requiring chest tube served as primary end points, with technical success, hemoptysis, operative time, and radiation dose serving as secondary end points. Pooled odds ratios (ORs) were calculated for the dichotomous variables. Pooled estimates of the mean difference (MD) were measured for the continuous variables. RESULTS: This meta-analysis included 9 studies. Seven studies were retrospective, and 2 studies were randomized controlled trials. A total of 6998 patients underwent either CTF-guided (n = 3858) or CCT-guided (n = 3154) lung biopsy. The diagnostic accuracy rate was significantly higher in the CTF group compared with the CCT group (OR, 0.32; P < 0.00001). No significant differences were detected between the CTF and CCT groups in terms of incidence rates of pneumothorax (OR, 0.95; P = 0.84), rates of pneumothorax requiring chest tube insertion (OR, 0.95; P = 0.84), technical success rates (OR, 0.41; P = 0.15), incidence rates of hemoptysis (OR, 1.19; P = 0.61), operative time (MD, -4.38; P = 0.24), and radiation dose (MD, 158.60; P = 0.42). A publication bias was found for the end points of pneumothorax requiring chest tube insertion and operative time. CONCLUSIONS: Compared with CCT-guided lung biopsy, CTF-guided lung biopsy could yield a higher diagnostic accuracy with similar safety and radiation exposure.

Computed Tomography-Guided Biopsy for Small (≤20 mm) Lung Nodules: A Meta-Analysis.

PURPOSE: This study was designed to evaluate the diagnostic accuracy of computed tomography (CT)-guided biopsy for small lung nodules (SLNs) (≤20 mm) and to assess related complication rates. METHODS: We reviewed the Pubmed, Embase, and Cochrane Library databases to identify all relevant studies published as of April 2020. Random effects modeling were then used to evaluate pooled data pertaining to technical success rates, diagnostic accuracy, pneumothorax rates, and rates of hemoptysis. The meta-analysis was conducted using Stata v12.0. RESULTS: In total, we identified 25 relevant studies for incorporation into this meta-analysis, incorporating 2922 total CT-guided lung biopsy. Pooled technical success rates, diagnostic accuracy, pneumothorax rates, and hemoptysis rates were 94% (95% confidential interval [CI], 0.91-0.98), 90% (95% CI, 0.88-0.93), 19% (95% CI:, 0.15-0.24), and 12% (95% CI, 0.08-0.15), respectively. We observed significant heterogeneity among these studies for all 4 of these parameters (I = 90.0%, 82.7%, 88.6%, and 88.4%, respectively). When we conducted a meta-regression analysis, we did not identify any variables that influenced diagnostic accuracy or technical success, pneumothorax, or hemoptysis rates. Publication bias risk analyses suggested that there was relatively little risk of publication bias pertaining to pneumothorax rates (P = 0.400) or hemoptysis rates (P = 0.377). In contrast, we detected a high risk of publication bias pertaining to reported technical success rates (P = 0.007) and diagnostic accuracy (P = 0.000). CONCLUSIONS: A CT-guided biopsy can be safely and effectively used to diagnose SLNs.

Computed Tomography-Guided Transfissural Coil Localization of Lung Nodules.

BACKGROUND: The objective of this study was to evaluate the feasibility, safety, and clinical effectiveness of preoperative computed tomography (CT)-guided transfissural coil localization (TFCL) of subfissural lung nodules. METHODS: Five patients with lung nodules who underwent CT-guided TFCL before video-assisted thoracoscopic surgery between November 2015 and December 2018 were included. Technical success rates of TFCL and wedge resection were assessed, as well complications and pathological results. RESULTS: The technical success rate of TFCL was 100%. Two patients experienced parenchymal hemorrhage around the needle path, and two patients experienced asymptomatic pneumothorax after TFCL. The technical success rate of the wedge resection of lung nodules was also 100%. The pathological diagnoses of the five nodules were minimally invasive adenocarcinoma (n = 3), adenocarcinoma in situ (n = 1), and inflammatory nodule (n = 1). CONCLUSION: CT-guided TFCL is a safe and effective method for the preoperative localization of subfissural lung nodules.

Sparse Blind Deconvolution with Nonconvex Optimization for Ultrasonic NDT Application.

In the field of ultrasonic nondestructive testing (NDT), robust and accurate detection of defects is a challenging task because of the attenuation and noising of the ultrasonic wave from the structure. For determining the reflection characteristics representing the position and amplitude of ultrasonic detection signals, sparse blind deconvolution methods have been implemented to separate overlapping echoes when the ultrasonic transducer impulse response is unknown. This letter introduces the ℓ1/ℓ2 ratio regularization function to model the deconvolution as a nonconvex optimization problem. The initialization influences the accuracy of estimation and, for this purpose, the alternating direction method of multipliers (ADMM) combined with blind gain calibration is used to find the initial approximation to the real solution, given multiple observations in a joint sparsity case. The proximal alternating linearized minimization (PALM) algorithm is embedded in the iterate solution, in which the majorize-minimize (MM) approach accelerates convergence. Compared with conventional blind deconvolution algorithms, the proposed methods demonstrate the robustness and capability of separating overlapping echoes in the context of synthetic experiments.

Arrival-Time Detection in Wind-Speed Measurement: Wavelet Transform and Bayesian Information Criteria.

The time-difference method is a common one for measuring wind speed ultrasonically, and its core is the precise arrival-time determination of the ultrasonic echo signal. However, because of background noise and different types of ultrasonic sensors, it is difficult to measure the arrival time of the echo signal accurately in practice. In this paper, a method based on the wavelet transform (WT) and Bayesian information criteria (BIC) is proposed for determining the arrival time of the echo signal. First, the time-frequency distribution of the echo signal is obtained by using the determined WT and rough arrival time. After setting up a time window around the rough arrival time point, the BIC function is calculated in the time window, and the arrival time is determined by using the BIC function. The proposed method is tested in a wind tunnel with an ultrasonic anemometer. The experimental results show that, even in the low-signal-to-noise-ratio area, the deviation between mostly measured values and preset standard values is mostly within 5 µs, and the standard deviation of measured wind speed is within 0.2 m/s.

A Study on Determining Time-Of-Flight Difference of Overlapping Ultrasonic Signal: Wave-Transform Network.

An ultrasonic sensors system is commonly used to measure the wall thickness of buried pipelines in the transportation of oil and gas. The key of the system is to precisely measure time-of-flight difference (TOFD) produced by the reflection of ultrasonic on the inner and outer surfaces of the pipelines. In this paper, based on deep learning, a novel method termed Wave-Transform Network is proposed to tackle the issues. The network consists of two parts: part 1 is designed to separate the potential overlapping ultrasonic echo signals generated from two surfaces, and part 2 is utilized to divide the sample points of each signal into two types corresponding to before and after the arrival time of ultrasonic echo, which can determine the time-of-flight (TOF) of each signal and calculate the thickness of pipelines. Numerical simulation and actual experiments are carried out, and the results show satisfactory performances.

Luminescence Lifetime-Based In Vivo Detection with Responsive Rare Earth-Dye Nanocomposite.

For years, luminescence lifetime imaging has served as a quantitative tool in indicating intracellular components and activities. However, very few studies involve the in vivo study of animals, especially in vivo stimuli-responsive activities of animals, as both excitation and emission wavelengths should fall into the near-infrared (NIR) optical transparent window (660-950 and 1000-1500 nm). Herein, this work reports a lifetime-responsive nanocomposite with both excitation and emission in the NIR I window (800 nm) and lifetime in the microsecond region. The incorporation of Tm3+ -doped rare-earth nanocrystals and NIR dye builds an efficient energy transfer pathway that enables a tunable luminescence lifetime range. The NaYF4 :Tm nanocrystal, which absorbs and emits photons at the same energy level, is found to be 33 times brighter than optimized core-shell upconversion nanocrystals, and proved to be an effective donor for NIR luminescence resonance energy transfer (LRET). The anti-interference capability of luminescence lifetime signals is further confirmed by luminescence and lifetime imaging. In vivo studies also verify the lifetime response upon stimulation generated in an arthritis mouse model. This work introduces an intriguing tool for luminescence lifetime-based sensing in the microsecond region.

A Study of Quantifying Thickness of Ferromagnetic Pipes Based on Remote Field Eddy Current Testing.

Remote Field Eddy Current Testing (RFECT) has broad applications in ferromagnetic pipe testing due to the same testing sensitivity to inner and outer wall defects. However, how to quantify wall thickness in the RFECT of pipes is still a big problem. According to researchers' studies, a linear relationship exists between the wall thickness, permeability and conductivity of a pipe and the phase of the RFECT signal. Aiming to quantify wall thickness by using this linear function, it is necessary to further study the effects of pipe permeability and conductivity on the phase of the RFECT signal. When the product value of the permeability and the conductivity of a pipe remains constant, the univariate analysis and Finite Element Analysis (FEA) are employed to analyze the variations among the phase of the RFECT signal caused by different couples of permeability and conductivity. These variations are calibrated by using a nonlinear fitting method. Moreover, Multi-Frequency Eddy Current Testing (MFECT) is applied to inverse the permeability and conductivity of a pipe to compensate for the quantification analysis of wall thickness. The methods proposed in this paper are validated by analyzing the simulation signals and can improve the practicality of RFECT of ferromagnetic pipes.