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To investigate the efficacy of medical treatment and balloon angioplasty for intracranial atherosclerosis using high-resolution MR vessel wall imaging (HR-MRI).In this prospective study, patients with symptomatic severe stenosis from January 2018 to August 2021 were treated with medical treatment or balloon angioplasty. The patients underwent HR-MRI at baseline and at 3, 6, and 12 months. Plaque characteristics at follow-up were compared with those at baseline using paired sample T-test or Wilcoxon rank sum test. The difference in the recurrence of ischemic events between two groups was compared.A total of 37 patients (26 males; mean age = 60.5 ± 11.6 years) were evaluated. Of 68 plaques, 42 (61.8%) were treated with medication only. At 12 months of medical treatment, maximum plaque length (p = 0.004), maximum wall thickness (p = 0.036), and plaque enhancement (p = 0.001) were significantly reduced than baseline. At 3 months after balloon angioplasty, luminal stenosis (p = 0.048) was significantly reduced compared to baseline. At 6 months after balloon angioplasty, maximum plaque length (p = 0.011), maximum wall thickness (p = 0.003), and luminal stenosis (p = 0.001) were significantly reduced than baseline. No difference was found in the recurrence of ischemic events between two groups (p = 0.458).Intracranial atherosclerotic plaque shrank and tended to be stable at 12 months of medical treatment. Plaque burden was significantly reduced 6 months after balloon angioplasty. This may provide evidence for the application and selection of treatment strategies for intracranial atherosclerotic disease.• Plaque burden and plaque enhancement were significantly reduced at 12 months of medical treatment compared to baseline. • Plaque burden was significantly reduced at 6 months after balloon angioplasty compared with baseline. • No significant difference in the recurrence rate of ischemic stroke between patients treated with medication and balloon angioplasty.

Background and Purpose: Aneurysmal wall enhancement (AWE) on vessel wall magnetic resonance imaging (VW-MRI) has been described as a new imaging biomarker of unstable unruptured intracranial aneurysms (UIAs). Previous studies of symptomatic UIAs are limited due to small sample sizes and lack of AWE quantification. Our study aims to investigate whether qualitative and quantitative assessment of AWE can differentiate symptomatic and asymptomatic UIAs. Methods: Consecutive patients with UIAs were prospectively recruited for vessel wall magnetic resonance imaging at 3T from October 2014 to October 2019. UIAs were categorized as symptomatic if presenting with sentinel headache or oculomotor nerve palsy directly related to the aneurysm. Evaluation of wall enhancement included enhancement pattern (0=none, 1=focal, and 2=circumferential) and quantitative wall enhancement index (WEI). Univariate and multivariate analyses were used to identify the parameters associated with symptoms. Results: Two hundred sixty-seven patients with 341 UIAs (93 symptomatic and 248 asymptomatic) were included in this study. Symptomatic UIAs more frequently showed circumferential AWE than asymptomatic UIAs (66.7% versus 17.3%, P P P =0.01; odds ratio=3.32 for WEI [95% CI, 1.51–7.26], P =0.003). The combination of AWE pattern and WEI had an area under the curve of 0.91 to identify symptomatic UIAs, with a sensitivity of 95.7% and a specificity of 73.4%. Conclusions: In a large cohort of UIAs with vessel wall magnetic resonance imaging, both AWE pattern and WEI were independently associated with aneurysm-related symptoms. The qualitative and quantitative features of AWE can potentially be used to identify unstable intracranial aneurysms.

OBJECTIVES To assess the value of multiparametric magnetic resonance imaging including intravoxel incoherent motion (IVIM), diffusion tensor imaging (DTI) and blood oxygen level dependent (BOLD) MRI in differentiating the severity of hepatic warm ischemia-reperfusion injury (WIRI) in a rabbit model. METHODS Fifty rabbits were randomly divided into a sham-operation group and four test groups (n = 10 for each group) according to different hepatic warm ischemia times. IVIM, DTI and BOLD MRI were performed on a 3 T MR scanner with 11 b values (0 to 800 s/mm2), 2 b values (0 and 500 s/mm2) on 12 diffusion directions, multiple-echo gradient echo (GRE) sequences (TR/TE, 75/2.57-24.25 ms), respectively. IVIM, DTI and BOLD MRI parameters, hepatic biochemical and histopathological parameters were compared. Pearson and Spearman correlation methods were performed to assess the correlation between these MRI parameters and laboratory parameters. Furthermore, receiver operating characteristic (ROC) curves were compiled to determine diagnostic efficacies. RESULTS True diffusion (Dslow), pseudodiffusion (Dfast), perfusion fraction (PF), mean diffusivity (MD) significantly decreased, while R2* significantly increased with prolonged warm ischemia times, and significant differences were found in all of biochemical and histopathological parameters (all P

Rationale and Objectives To evaluate the feasibility of simultaneous multislice (SMS)-accelerated, readout-segmented echo-planar imaging (rs-EPI, RESOLVE) with the use of special-purpose coils for head and neck assessment, particularly in patients diagnosed with head and neck malignant tumors, through comparison with the conventional RESOLVE and RESOLVE with readout partial-Fourier technique (RESOLVE-RPF). Materials and Methods Twenty-five healthy volunteers and 24 patients with histologically proven malignant head and neck tumors were included in this prospective study. The MR exam included conventional RESOLVE, RESOLVE-RPF, prototypic SMS-RESOLVE, and prototypic SMS-RESOLVE with special-purpose coils (SMS-RESOLVE + Coils), acquired at b-values of both 0 and 800 s/mm2. Image quality was evaluated qualitatively (reader score) and quantitatively (tumor distortion, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), SNR efficiency) and compared. For volunteer imaging, the image quality of target tissues at three different typical levels (oropharyngeal, hypopharyngeal, and thyroid level) were evaluated. For patient imaging, the image quality of primary tumors and metastatic lymph nodes was evaluated. Results The acquisition time was 3:37 minutes for RESOLVE, 2:58 minutes for RESOLVE-RFP, 2:01 minutes for SMS-RESOLVE and 2:01 minutes for SMS-RESOLVE + Coils, with a 44% reduction compared to the conventional RESOLVE. No significant differences in the reader scores, tumor distortion, or ADC values of the lesions were found among the protocols. The SNR and CNR at the oropharyngeal and hypopharyngeal level of SMS-RESOLVE + Coils were markedly improved and significantly higher than those of RESOLVE, as well as the SNR, SNR efficiency of tumors and lymph nodes. No significant differences in quantitative measurements were found at the thyroid level. Conclusion SMS-RESOLVE + Coils protocol is an effective and promising approach to optimally reducing the total acquisition time, and could be a good alternative with a superior SNR and SNR efficiency in comparison with conventional RESOLVE. However, the limited application in the lower neck region needs further investigation.

Since the adoption of the open-door policy, the Chinese dietary pattern has changed greatly. Based on the dietary changes, this study analyzed the arable land and water footprints (WFs) for the food consumption of urban and rural residents in China. The results showed that the arable land demand and WFs for meat, vegetable oil, soybeans and liquor exceeded those for other foods, and the per capita arable land and WFs for food consumption of urban residents were higher than those of rural residents. The total arable land and WFs for the food consumption of residents increased by 16.9 million ha (from 91.1 to 108 million ha) and 214.5 billion m

We aimed to investigate differential characteristics of plaque in the middle cerebral artery (MCA) and hemodynamics in patients with ischemic stroke and transient ischemic attack (TIA), and to develop a predictive model for the presence of ischemic stroke and neurological impairment.Sixty-seven patients with acute ischemic events in MCA territory who underwent high-resolution vessel wall imaging between September 2016 and August 2018 were reviewed retrospectively. Patients were assigned to either the stroke group or TIA group, according to diffusion-weighted imaging and neurological examination. Plaque characteristics and anterograde score (AnS) were calculated. Tmax6.0-s volume was acquired by RApid Processing of perfusIon and Diffusion software. Multivariate logistic regression analysis and multiple linear regression analysis were performed to establish a predictive model for irreversible infarction occurrence and clinical severity.Forty-five patients were assigned to the stroke group, and 22 were assigned to the TIA group. Plaque length, intraplaque hemorrhage (IPH), enhancement, AnS, and Tmax6.0-s volumes were significantly different between the two groups (p0.05). IPH and AnS were independent predictors for patients with stroke (p = 0.020 and 0.034, respectively). Tmax6.0-s volume, IPH, hypertension, and AnS were associated with high National Institutes of Health Stroke Scale (NIHSS) scores (all p0.05, R = 0.725, and adjusted RIPH and AnS are useful in predicting stroke occurrence. Tmax6.0-s volume, IPH, hypertension, and AnS are associated with neurological impairment of the patients.• Ischemic stroke and TIA patients have different plaque characteristics and hemodynamics. • Intraplaque hemorrhage and anterograde score have high diagnostic efficiency for ischemic stroke. • The combination of Tmax6.0-s volume, intraplaque hemorrhage, hypertension, and anterograde score can predict the National Institutes of Health Stroke Scale scores of patients.

The purpose of this study was to investigate cerebral blood flow (CBF) changes in hemodialysis patients with arterial spin labeling (ASL) and to correlate these changes with clinical risk factors and neurocognitive function. Thirty-two hemodialysis patients and 35 age-, sex-, and education-matched healthy controls (HCs) were recruited in this prospective study. The Mini-Mental State Examination (MMSE) was performed to evaluate neurocognitive function. Pulsed ASL was performed to measure CBF. Two independent sample t-test was used to explore the CBF difference between the patients and HCs. Multiple stepwise regression was used to investigate the risk factors for CBF in patients. Correlation analysis was used to explore the relationship between the MMSE scores and CBF changes with and without adjusting for anemia status. Compared to HCs, the hemodialysis patients showed significantly increased CBF in some neurocognition-related cerebral regions (all P

BACKGROUND The application value of T2 mapping in evaluating cervical cancer (CC) features remains unclear. PURPOSE To investigate the role of T2 values in evaluating CC classification, grade, and lymphovascular space invasion (LVSI) in comparison to apparent diffusion coefficient (ADC), and to compare synthetic T2 -weighted (T2 W) images calculated from T2 values to conventional T2 W images for CC staging. STUDY TYPE Retrospective. POPULATION Sixty-three patients with histopathologically confirmed CC. FIELD STRENGTH/SEQUENCE 3T, conventional T2 W turbo spin-echo, diffusion-weighted echo-planar, and accelerated T2 mapping sequence. ASSESSMENT T2 and ADC values between different pathological features of CC were compared. The diagnostic accuracies of conventional and synthetic T2 W images in staging were also compared. STATISTICAL TESTS Parameters were compared using an independent t-test, Wilcoxon signed-rank test, and the chi-square test. Receiver operating characteristic analysis was performed. RESULTS The T2 values varied significantly between well/moderately differentiated and poorly differentiated tumors ([92.8 ± 9.5 msec] vs. [83.8 ± 9.5 msec], P

In traditional research in insurance and finance, a firm is subject to immediate liquidation when its asset value process drops to an absorbing low barrier. This treatment greatly simplifies research but largely ignores the complexity of the liquidation procedure in the real world. In banking and finance, many researchers have taken into account the features of Chapter 7 liquidation and Chapter 11 reorganization of the U.S. Bankruptcy Code. Also, there have been similar discussions in insurance regulation, but few works have been done to achieve a quantitative understanding of the liquidation risk in insurance under contemporary regulatory frameworks. In this paper, we quantify the rehabilitation proceeding in insurance, which is akin to Chapter 11 reorganization of the U.S. Bankruptcy Code, and we conduct a probabilistic analysis of the liquidation risk of an insurance company having the option of rehabilitation. In doing so, we construct a three-barrier model to describe the solvent and insolvent states in which the surplus process follows different time-homogeneous diffusions. We derive analytical expressions for the liquidation probability and the Laplace transform of the liquidation time with a fixed grace period and then extend the study to the case with independent exponentially distributed grace periods. If further restricted to the constant elasticity of variance (CEV) framework, the obtained formulas become completely explicit.

Background and Purpose— This study aims to investigate the association between the characteristics of atherosclerotic plaques of middle cerebral artery and recurrent ischemic stroke using magnetic resonance vessel wall imaging. Methods— One hundred and five patients with ischemic stroke attributed to middle cerebral artery plaque underwent high-resolution black-blood magnetic resonance vessel wall imaging. They were divided into group 1, with the first episode of acute stroke (imaging within 4 weeks of stroke, n=44); group 2, with recurrent acute stroke (n=29); and group 3, with chronic stroke (imaging after 3 months of stroke, n=32). Plaque characteristics including plaque area, plaque burden, contrast-enhancement ratio, eccentricity, and degree of stenosis were measured and compared across 3 groups. Association between plaque characteristics and recurrent strokes was investigated by multivariate analysis. Results— Plaque burden was significantly greater in recurrent stroke group than the other 2 groups (median: group 2, 82.7%, versus group 1, 76.3%, and group 3, 73.4%; P =0.001). Patients with acute stroke had higher enhancement ratio than patients with chronic stroke (median: group 1, 1.59, and group 2, 1.90, versus group 3, 1.33; P =0.014). Comparing to first-onset acute stroke patients, recurrent stroke patients were older, more likely with female sex and hypertension, and had higher plaque burden. After adjustment of clinical factors, plaque burden was the only independent imaging feature associated with recurrent stroke (odds ratio, 2.26, per 10% increase [95% CI, 1.03–4.96]; P =0.042). Conclusions— Higher plaque burden of middle cerebral artery identified on magnetic resonance vessel wall imaging is independently associated with recurrent ischemic stroke.

To evaluate liver perfusion changes and their effect on liver regeneration (LR) after partial hepatectomy (PH) using intravoxel incoherent motion (IVIM) and T2* mapping in a rat model.One hundred and two rats underwent 30%, 50%, or 70% PH. Within each group (n = 34), rats in MR imaging subgroup (n = 10) underwent liver IVIM and T2* mapping before and within 2 h, 1, 2, 3, 5, 7, 14, and 21 days post-PH to measure D*, perfusion fraction (PF), and T2* values. Three rats from histologic subgroup (n = 24) sacrificed at each time point for hepatocyte Ki-67 indices and diameters measurement.Liver D* and PF values decreased immediately post-PH, then returned to original level as LR progressed in all groups. PF values in 70% PH group were significantly lower than in the other two groups (p .05). D* and PF values correlated significantly with hepatocyte Ki-67 indices (r = -0.588 to -0.915; p .05) and hepatocyte diameter (r = -0.555 to -0.792; p .05). Liver T2* values decreased immediately within 2 h post-PH, then increased to a high level and followed with returning to original level gradually. The duration of the high T2* levels was consistent with Ki-67 indices.Liver perfusion decreased immediately followed with increasing gradually after PH. IVIM and T2* mapping are promising methods for monitoring changes of liver perfusion. IVIM-derived D* value is the best indicator in reflecting the process of LR noninvasively.

BACKGROUND: Magnetic resonance imaging (MRI) has been used increasingly as an adjunct examination to ultrasound (US) for the evaluation of fetal anomalies. The purpose of this study was to determine whether the accuracy and confidence of diagnosing fetal vertebral anomalies are improved with MRI. We also assessed whether fetal MRI provides additional information when diagnosing fetal vertebral anomalies. METHODS: We performed a single-center, retrospective study of 127 pregnant women with fetuses suspected of having vertebral anomalies on US examination; women also underwent fetal MRI scanning. Comparisons of diagnostic accuracy and confidence were made between MRI and US for the identification of fetal vertebral anomalies. We also assessed any additional information provided by MRI. McNemar’s paired binomial test, chi-square test, or Fisher’s exact test were used to compare the diagnostic ability between MRI and US. In all cases, postnatal or postmortem imaging findings were used as reference standards. RESULTS: A total of 127 participants were recruited between December 2015 and January 2021. Fetal vertebral anomalies were detected in 63.8% (81/127) cases and found to be negative in 36.2% (46/127) of cases at follow up. The diagnostic accuracy of vertebral anomalies was 46.9% (38/81) for US and 84.0% (68/81) for MRI [difference, 37.1%; 95% confidence interval (CI): 27% to 48%; P

To explore changes of cerebral gray matter volumes (GMV) in hemodialysis patients, the clinical risk factors for GMV changes, and the relationship between GMV changes and neuropsychological tests results. Eighty-eight hemodialysis patients and seventy-six healthy controls (HCs) were recruited in this study. Fifty patients underwent follow-up magnetic resonance, blood biochemical examinations, and neuropsychological test (1.75±0.55 years). Changes in GMV between patients and HCs, longitudinal GMV changes in patients were explored. The clinical risk factors for the longitudinal GMV changes, the correlations between longitudinal GMV changes and neuropsychological tests changes in hemodialysis patients were analyzed. Compared to HCs, the hemodialysis patients had diffusely decreased in GMV (with age, sex, and total intracranial volume [TIV] as covariates, PPPPP=0.02). The decreased left caudate volumes were positively correlated with reduced MMSE scores in hemodialysis patients (rs=0.437, P=0.033). Hemodialysis patients had diffused GM atrophy over time, which was related to cognitive impairment.

We have studied the high-pressure compression behavior of molybdenum up to 60 GPa by synchrotron radial x-ray diffraction (RXRD) in a diamond anvil cell (DAC). It is found that all diffraction peaks of molybdenum undergo a split at around 27 GPa, and we believe that a phase transition from a body-centered cubic structure to a rhombohedral structure at room pressure has occurred. The slope of pressure–volume curve shows continuity before and after this phase transition, when fitting the pressure–volume curves of the body-centered cubic structure at low pressure and the rhombohedral structure at high pressure. A bulk modulus of 261.3 (2.7) GPa and a first-order derivative of the bulk modulus of 4.15 (0.14) are obtained by using the nonhydrostatic compression data at the angle ψ = 54.7° between the diffracting plane normal and stress axis.

Background and Purpose: 3D pointwise encoding time reduction magnetic resonance angiography (PETRA-MRA) is a promising non-contrast magnetic resonance angiography (MRA) technique for intracranial stenosis assessment but it has not been adequately validated against digital subtraction angiography (DSA) relative to 3D-time-of-flight (3D-TOF) MRA. The aim of this study was to compare PETRA-MRA and 3D-TOF-MRA using DSA as the reference standard for intracranial stenosis assessment before and after angioplasty and stenting in patients with middle cerebral artery (MCA) stenosis.Materials and Methods: Sixty-two patients with MCA stenosis (age 53 ± 12 years, 43 males) underwent MRA and DSA within a week for pre-intervention evaluation and 32 of them had intracranial angioplasty and stenting performed. The MRAs' image quality, flow visualization within the stents, and susceptibility artifact were graded on a 1–4 scale (1 = poor, 4 = excellent) independently by three radiologists. The degree of stenosis was measured by two radiologists independently on DSA and MRAs.Results: There was an excellent inter-observer agreement for stenosis assessment on PETRA-MRA, 3D-TOF-MRA, and DSA (ICCs > 0.90). For pre-intervention evaluation, PETRA-MRA had better image quality than 3D-TOF-MRA (3.87 ± 0.34 vs. 3.38 ± 0.65, P < 0.001), and PETRA-MRA had better agreement with DSA for stenosis measurements compared to 3D-TOF-MRA (r = 0.96 vs. r = 0.85). For post-intervention evaluation, PETRA-MRA had better image quality than 3D-TOF-MRA for in-stent flow visualization and susceptibility artifacts (3.34 ± 0.60 vs. 1.50 ± 0.76, P < 0.001; 3.31 ± 0.64 vs. 1.41 ± 0.61, P < 0.001, respectively), and better agreement with DSA for stenosis measurements than 3D-TOF-MRA (r = 0.90 vs. r = 0.26). 3D-TOF-MRA significantly overestimated the stenosis post-stenting compared to DSA (84.9 ± 19.7 vs. 39.3 ± 13.6%, p < 0.001) while PETRA-MRA didn't (40.6 ± 13.7 vs. 39.3 ± 13.6%, p = 0.18).Conclusions: PETRA-MRA is accurate and reproducible for quantifying MCA stenosis both pre- and post-stenting compared with DSA and performs better than 3D-TOF-MRA.

Purpose Clinical approach for staging cerebral venous sinus thrombosis (CVST) depends on the duration from symptom onset to clinical diagnosis, which is subjective and may be incorrect. To investigate if T1-weighted signal characteristics of the thrombus can be used for staging the thrombus on segment level and predicting endovascular therapy outcome. Methods Ninety-one CVST patients underwent non-contrast-enhanced T1-weighted 3D variable-flip-angle fast-spin-echo (T1-SPACE) and 29 of them received endovascular therapy. We divided the 91 patients into acute, subacute, and chronic CVST stage according to the clinical approach, and then analyzed the T1 weighted signal characteristics (i.e., thrombus shape and signal intensity) of the thrombus at each stage. To investigate the endovascular therapy outcome associated with the thrombus stage and signal characteristics, we evaluated the thrombolytic ratio on patient level and recanalization rate on segment level, respectively. Results The thrombi at acute or chronic stage were depicted as isointense signals but as hyperintense signals at subacute stage. Compared to the thrombus at acute stage, the thrombus at chronic stage was contractive and can be distinguished. Developing thrombi at transition periods of acute-to-subacute or subacute-to-chronic stage were found appearing mixed iso-/hyper-intense signals. On patient’s level, the patients at earlier stage had higher thrombolytic ratio (acute: 80.7 ± 18.3%, subacute: 62.6 ± 36.3%, chronic: 22.9 ± 24.2%). On segment level, the thromboembolic segments of isointense or mixed iso-/hyper-intense thrombi at non-chronic stage had good thrombolytic outcome. Conclusion T1-weighted signal characteristics of the thrombus can be used for staging CVST and predicting the endovascular therapy outcome.

Study Objectives The relationship of iron with cognitive and motor impairment in idiopathic rapid eye movement sleep behavior disorder (iRBD) remains unknown. Methods Twenty-nine (29) patients and 28 healthy controls (HCs) underwent susceptibility weighted imaging and susceptibility mapping. These images were used to evaluate the nigrosome-1 (N1) sign in the substantia nigra (SN), global and regional high-iron (RII) content, and volume of subcortical nuclei. Results The number of iRBD patients with N1 loss (12) was significantly higher than HCs (2) (p = 0.005). Compared with HCs, the iRBD patients had reduced volume of the right caudate nucleus (RCN) (p < 0.05, false discovery rate [FDR] correction) but no significant changes in global and RII iron of the subcortical nuclei (all p > 0.05, FDR correction). Multiple regression analysis revealed that: for cognitive function, the RII iron of the RCN was significantly correlated with visuospatial function and the global iron of the right dentate nucleus (RDN) was correlated with memory function; for motor function, the RII iron of the left DN (LDN) and global iron of the left CN correlated with the Alternate-Tap test (left, average), the global iron of the LDN correlated with the Alternate-Tap test (right), and the global iron of the left GP correlated with the 3-m Timed Up and Go test (all p < 0.05, FDR correction). Conclusions Our exploratory analysis found that iRBD patients had a higher incidence of N1 loss and reduced RCN volume after FDR correction. Cognitive and motor impairment were associated with iron deposition in several cerebral nuclei after FDR correction.

Asset allocation with a derivative security is studied in a hidden, Markovian regime-switching, economy using filtering theory and the martingale approach. A generalized delta-hedged ratio and a generalized elasticity of an option are introduced to accommodate the presence of the information state process and the derivative security. Malliavin calculus is applied to derive a solution for a general utility function which includes an exponential utility, a power utility, and a logarithmic utility. A compact solution is obtained for a logarithmic utility. Some economic implications of the solutions are discussed.

Land use change under rapid urbanization can drastically change terrestrial ecological conditions. This study presents an integrated analysis of land use dynamics and the resultant ecological impacts on sustainable development over the past 25 years (1990–2015) in response to urban development. Remote sensing and geographic information system techniques were employed to examine the spatiotemporal trajectory of land use changes. Based on the analysis of the equivalent factor table for land use types and ecosystem services value (ESV), the value of ecosystem services was calculated in the case study of Fuyang, China. Correlations were identified between ESV and a family of landscape fragmentation metrics. The results showed that the area affected by land use changes represented 33.35% of the total study area and caused a 31.74 million US$·a−1 decrease in ESV from 1990 to 2015. The ESV was spatially imbalanced and generally low in urban areas. Ecological plans for cropland reforestation and urban green projects were effective in slowing ESV losses while urban areas rapidly developed. In addition, total ESV was negatively correlated with edge density (ED), patch density (PD), landscape shape index (LSI), and Shannon's diversity index (SHDI) but positively correlated with aggregation index (AI), suggesting that landscape fragmentation had an adverse impact on the overall ESV in Fuyang. Therefore, sustainable land use planning must be integrated with landscape patterns to provide useful guidance regarding the spatial regulation of a given area to protect and improve ecosystem services.

Additional file 1.

At present, a new round of scientific and technological revolution and industrial transformation with information technology at its core are accelerating. At present, a new round of scientific and technological revolution and industrial transformation with information technology at its core is accelerating. The challenge of new economy and new industry has put forward new requirements for the training of talents in China. The challenges of new economy and new industry have put forward new requirements for the cultivation of engineering talents in China. Based on corpus, this study constructed a model of intelligent English teaching assisted by virtual corpus. The traditional teaching of college English reading is based on, around, and for texts. Using DDL model, teachers can break the limitation of textbooks. On the basis of analyzing the general idea of the text, they can search out massive real corpus related to the general idea of the text by searching the core words in the text, so as to provide extensive reading resources for students in the maximum range. At the same time, teachers can rely on the corpus to design different types of teaching activities, realize student-centered task-based, inquiry-based, and autonomous learning and cultivate students’ critical thinking ability, practical ability, and cross-cultural communication ability. This model breaks the limitation of “classroom + textbook,” realizes student-centered task-based, exploratory, and autonomous learning, trains interdisciplinary new engineering talents needed by emerging industries and new economy in the future, and promotes the sustainable development of English teaching. Corpus-data-driven college English teaching mode breaks the limitation of “classroom + textbook,” changes the traditional college English teaching mode, and realizes student-centered task-oriented, inquiry-based, and autonomous learning.

The study aimed to analyze the feasibility of a radial turbo-spin-echo (TSE) T2 mapping to differentiate the histological grades and lymphovascular space invasion (LVSI) of cervical squamous cell carcinoma (CSCC) in comparison with diffusion-weighted imaging (DWI).A total of 58 patients with CSCC and 40 healthy volunteers underwent T2 mapping and DWI before therapy. The T2 and apparent diffusion coefficient (ADC) values were calculated using different tumor characteristics. The differences, efficacies and correlations between parameters were determined.The T2 and ADC values were significantly different between CSCC and normal cervical stroma (both p 0.05). Poorly differentiated (G3) tumor showed lower T2 and ADC values than well differentiated (G1) and moderately differentiated (G2) tumor (all p 0.05). The T2 values were significantly lower in LVSI-positive CSCC than LVSI-negative CSCC (p 0.05). No significant difference was found in ADC values for LVSI status (p = 0.561). The area under the ROC (AUC) for T2 and ADC values to distinguish G1/G2 and G3 tumor were 0.741 and 0.763, respectively. The AUC for T2 and ADC values to distinguish LVSI-positive and LVSI-negative CSCC were 0.877 and 0.537, respectively. The T2 and ADC values were negatively correlated with the tumor grades (r = -0.402 and r = -0.339, respectively).Radial TSE T2 mapping is feasible for CSCC. Similar to ADC values, quantitative T2 values could serve as a noninvasive biomarker to predict histological grades preoperatively. Moreover, T2 values could determine the presence of LVSI better than ADC values.

Purpose To compare integrated slice-specific dynamic shimming (iShim) diffusion weighted imaging (DWI) and single-shot echo-planar imaging (SS-EPI) DWI in image quality and pathological characterization of rectal cancer. Materials and methods A total of 193 consecutive rectal tumor patients were enrolled for retrospective analysis. Among them, 101 patients underwent iShim-DWI (b = 0, 800, and 1600 s/mm2) and 92 patients underwent SS-EPI-DWI (b = 0, and 1000 s/mm2). Qualitative analyses of both DWI techniques was performed by two independent readers; including adequate fat suppression, the presence of artifacts and image quality. Quantitative analysis was performed by calculating standard deviation (SD) of the gluteus maximus, signal intensity (SI) of lesion and residual normal rectal wall, apparent diffusion coefficient (ADC) values (generated by b values of 0, 800 and 1600 s/mm2 for iShim-DWI, and by b values of 0 and 1000 s/mm2 for SS-EPI-DWI) and image quality parameters, such as signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of primary rectal tumor. For the primary rectal cancer, two pathological groups were divided according to pathological results: Group 1 (well-differentiated) and Group 2 (poorly differentiated). Statistical analyses were performed with p Results Compared with SS-EPI-DWI, significantly higher scores of image quality were obtained in iShim-DWI cases (P background was significantly reduced on b = 1600 s/mm2 images and ADC maps of iShim-DWI. Both SNR and CNR of b = 800 s/mm2 and b = 1600 s/mm2 images in iShim-DWI were higher than those of b = 1000 s/mm2 images in SS-EPI-DWI. In primary rectal cancer of iShim-DWI cohort, SIlesion was significantly higher than SIrectum in both b = 800 and 1600 s/mm2 images. ADC values were significantly lower in Group 2 (0.732 ± 0.08) × 10− 3 mm2/s) than those in Group 1 ((0.912 ± 0.21) × 10− 3 mm2/s). ROC analyses showed significance of ADC values and SIlesion between the two groups. Conclusion iShim-DWI with b values of 0, 800 and 1600 s/mm2 is a promising technique of high image quality in rectal tumor imaging, and has potential ability to differentiate rectal cancer from normal wall and predicting pathological characterization.

Group recommendation has received great attention owing to its practical value in real applications. However, group members are implicit and groups are formed occasionally in some scenarios. Existing solutions for latent group recommendation assumes a user belongs to a specific group, and totally ignore the possible correlation between the user' $s$ preferences and other groups' preferences. In addition, existing methods cannot deal with new items cold-start problem effectively because they only focus on which items are favored by the group without considering the hidden related information between items. These weaknesses usually lead to poor performance of latent group recommendation. To address the problems above, this paper proposes a latent group recommendation method based on double fuzzy clustering and matrix tri-factorization (DFCMTF -LGR). Firstly, this method utilizes unsupervised learning to implement potential feature extraction and double fuzzy clustering for users and items. Secondly, a novel matrix tri-factorization method is presented to adjust the membership of user-to-group, item-to-item category, and the incidence of group-to-item category is obtained. Finally, latent groups are detected according to user-to-group membership, and group rating can be generated in accordance with group-to-item category incidence matrix and item-to-item category membership. Experimental results on real datasets demonstrate that our proposed DFCMTF-LGR has better performance compared with state-of-the art methods.

A human hand gesture recognition algorithm based on multi-scale hybrid features is pro-posed. A large number of gesture data images are organized and annotated by automatic im-age annotation algorithm. Based on dense sampling, the multi-scale Gaussian pyramid is taken into account for enhancing the image details; it can realize the recognition of both large and small target gestures. Meanwhile, according to the aggregation and distribution of gestures, statistical analysis is used to optimize the size and aspect ratio of anchors, which can further improve the accuracy of recognition. The experiment results show that the mean average precisions of this algorithm can be improved to 99.7% and 93.3% for the simple gesture and complex gesture, respectively, which are higher than that obtained by these traditional methods, such as faster region-convolution neural network (Faster R-CNN), You Only Look Once (YOLO), and SSD.

Agricultural land fragmentation has an important impact on ecosystem services, especially food production. However, the relationship between land fragmentation and production diversification remains controversial and requires further analysis. This study characterized the dynamics of land fragmentation and production diversification in Zhejiang Province, China, from 1995 to 2015 using remote sensing, landscape metrics, and a diversification assessment approach. The results showed that Zhejiang Province experienced increasing fragmentation of agricultural landscapes and profound diversification of agricultural production. Fragmentation had a significant negative effect on grain crop production, but it had a significant positive effect on production diversification. These findings showed that fragmentation is an important driver of the diversification of agriculture and contributes to increased dietary diversity in local households. Therefore, we believe that when addressing land fragmentation issues, both the positive and negative impacts of fragmentation in different local conditions and circumstances should be taken into account. Our findings will provide scientific support for land consolidation management and agricultural land resource protection.

To quantitatively evaluate the volume of the ischemic penumbra using susceptibility-weighted imaging and mapping (SWIM) of asymmetrical prominent cortical veins (APCVs) in patients with acute ischemic stroke. Eighty-five eligible patients with acute ischemic stroke on admission within 12 h from symptom onset were studied. The APCVs on SWIM were quantitatively (SWI-volume) and semi-quantitatively (SWI-Alberta Stroke Program Early CT Score, SWI-ASPECTS) evaluated to calculate mismatch. To assess the diagnostic efficacy of APCVs on SWIM, comparative analyses were performed between SWIvolume-DWI mismatch and SWIASPECTS-DWI mismatch, using PWI-DWI mismatch as a reference. Correlations were calculated between the mismatches, as well as between SWI-volume and time-to-maximum (Tmax) > 6 s volume. Additionally, each of these mismatches was correlated with the National Institute of Health Stroke Scale (NIHSS). The sensitivity, negative predictive value, and accuracy of SWIvolume-DWI mismatch were demonstrably higher than SWIASPECTS-DWI mismatch (100% vs. 53.7%, 100% vs. 9.5%, 97.7% vs. 54.5%, respectively). A significant positive correlation was found between SWIvolume-DWI and PWI-DWI mismatch (r = 0.691, p 6 s volume (r = 0.786, p < 0.001). A significant negative correlation was found between SWIvolume-DWI mismatch and NIHSS (r = − 0.360, p = 0.022), as well as between SWIASPECTS-DWI mismatch and NIHSS (r = − 0.499, p = 0.001). SWIvolume-DWI mismatch had higher diagnostic efficacy than SWIASPECTS-DWI mismatch in defining the ischemic penumbra and showed good consistency with PWI-DWI mismatch in acute ischemic stroke. Quantitation of APCVs using SWIM provided an accurate method for determining hypoperfusion and provided a reliable method to reflect the hypoxia of penumbra. • SWI volume -DWI mismatch has higher diagnostic efficacy than SWI ASPECTS -DWI mismatch in defining the ischemic penumbra. • SWI volume -DWI mismatch shows good consistency with PWI-DWI mismatch in managing penumbra in acute ischemic stroke. • Quantitation of APCV volume using SWIM provided an accurate method for determining the hypoperfusion area and provided a reliable method to reflect the hypoxia of penumbra.

Background: A rapid lateral flow test (Peptest) to detect pepsin in saliva/sputum has been considered as a valuable method for diagnosing laryngopharyngeal reflux (LPR) and gastroesophageal reflux disease (GERD). The aim of this meta-analysis is to analyze the utility of Peptest for diagnosis of LPR and GERD. Methods: PubMed, EMBASE, and the Cochran Library (from January 1980 to 26 January 2020) were searched for pepsin in saliva for LPR/GERD diagnosis. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the curve data were summarized to examine the accuracy. Results: A total of 16 articles that included 2401 patients and 897 controls were analyzed. The pooled sensitivity and specificity for the diagnosis of GERD/LPR with Peptest were 62% (95% confidence interval [CI] 49%–73%) and 74% (95% CI 50%–90%), respectively. The summarized diagnostic odds ratio and area under the curve were 5.0 (95% CI 2–19) and 0.70 (95% CI 0.66–0.74), respectively. Conclusion: Peptest shows moderate diagnostic value for LPR and GERD. More studies with standard protocols should be done to verify its usefulness.

Background: Precise and reliable brain morphometry analysis is critical for clinical and research purposes. The magnetization-prepared rapid gradient echo (MPRAGE), multi-echo MPRAGE (MEMPRAGE) and magnetization-prepared 2 rapid acquisition gradient echo (MP2RAGE) sequences have all been used to acquire brain structural images, but it is unclear which of these sequences is the most suitable for brain morphometry and whether the number of coil channels (20 or 32) affects scan precision. This study aimed to assess the impact of T1-weighted image acquisition variables (sequence and head coil) on the repeatability of resultant automated volumetric measurements., Methods: Twenty-four healthy volunteers underwent back-to-back scanning protocols with three sequences and two different coils (i.e., six scanning conditions in total) presented in a randomized order in a single session. MorphoBox prototype and FreeSurfer were used for brain segmentation. Brain structures were divided into cortical and subcortical regions for more precise analysis. The acquired volume and thickness values were used to calculate test-retest variability (TRV) values. TRV values from the six different combinations were compared for total brain structures, total cortical structures, total subcortical structures, and every single structure., Results: The median TRV value for all brain regions was 1.23% with MorphoBox and 3.14% with FreeSurfer. When using FreeSurfer results to compare the six combinations, for total brain structures volume and total cortical structures volume and thickness, the MEMPRAGE-32 channel combination showed significantly lower TRV values than the others (P, Conclusions: TRV values were generally low, indicating generally high reliability for every region. The MEMPRAGE sequence was the most reliable of the three sequences for total brain structures and cortical structures. However, MP2RAGE was the most reliable for subcortical structures. The 32-channel coil showed better repeatability results than the 20-channel coil.

BACKGROUND AND PURPOSE: Not all tandem occlusions diagnosed on traditional vascular imaging modalities, such as MRA, represent actual complete ICA occlusion. This study aimed to explore the utility of high-resolution vessel wall imaging in identifying true ICA tandem occlusions and screening patients for their suitability for endovascular recanalization. MATERIALS AND METHODS: Patients with no signal in the ICA on MRA were retrospectively reviewed. Two neuroradiologists independently reviewed their high-resolution vessel wall images to assess whether there were true tandem occlusions and categorized all cases into intracranial ICA occlusion, extracranial ICA occlusion, tandem occlusion, or near-occlusion. DSA classified patient images into the same 4 categories, which were used as the comparison with high-resolution vessel wall imaging. The suitability for recanalization of occluded vessels was evaluated on high-resolution vessel wall imaging compared with DSA. RESULTS: Forty-five patients with no ICA signal on MRA who had available high-resolution vessel wall imaging and DSA images were included. Among the 34 patients (34/45, 75.6%) with tandem occlusions on DSA, 18 cases also showed tandem occlusions on high-resolution vessel wall imaging. The remaining 16 patients, intracranial ICA, extracranial ICA occlusions and near-occlusions were found in 2, 6, and 8 patients, respectively, on the basis of high-resolution vessel wall imaging. A total of 20 cases (20/45, 44.4%) were considered suitable for recanalization on the basis of both DSA and high-resolution vessel wall imaging. Among the 25 patients deemed unsuitable for recanalization by DSA, 11 were deemed suitable for recanalization by high-resolution vessel wall imaging. CONCLUSIONS: High-resolution vessel wall imaging could allow identification of true ICA tandem occlusion in patients with an absence of signal on MRA. Findings on high-resolution vessel wall imaging can be used to screen more suitable candidates for recanalization therapy.

Land suitability analysis is an important step in land use planning for livestock development because of its high efficiency to allocate livestock farms to the most suitable land areas and minimize adverse effects on environment. This study aimed to use two multi-criteria analysis approaches: Weighted Linear Combination (WLC) and Ordered Weighted Averaging (OWA), to comparatively evaluate and map land use suitability for livestock production in Hangzhou metropolitan area, China. The evaluation used eight factors as suitability criteria, relating to topographic, environmental, human factors, and socio-economic data. The analytic hierarchy process (AHP) method and GIS techniques were integrated into the evaluation models to create the land suitability map. The results of WLC approach showed that 11.4% of the total area was highly suitable for livestock production while 48.6% was unsuitable. Of these, areas located far from central city had higher suitability, while areas close to the urban district, drinking water source area, ecological and natural conservation area, had lower suitability. Sensitivity analysis indicated this expert suitability results for livestock production were robust. Indirect validations conducted by mutual comparisons of suitability maps computed using the WLC and OWA approaches demonstrated 90.4% of the overall agreement with a kappa coefficient of 0.857, indicating that both methods provide very similar spatial land use suitability distributions. Ecological fitness was evaluated by comparing the suitability analysis result with a previous livestock development planning and several recommendations aimed at improving the long-term livestock development plans were made for Hangzhou.

We consider the optimal financing (capital injections) and dividend payment problem for a Brownian motion model in the case of restricted dividend rates. The company has no obligation to inject capitals and therefore, the bankruptcy risk is present. Capital injections, if any, will incur both fixed and proportional transaction costs and dividend payments incur proportional transaction costs. The aim is to find the optimal strategy to maximize the expected present value of dividend payments minus the total cost of capital injections up to the time of bankruptcy. The problem is formulated as a mixed impulse-regular control problem. We address the problem via studying three cases of two auxiliary functions. We derive important analytical properties of the auxiliary functions and use them to study the value function and then identify the optimal control strategy. We show that the optimal dividend control is of threshold type and the optimal financing strategy prescribes to either never inject capitals or inject capitals only when the surplus reaches 0 with a fixed lump sum amount.

BACKGROUND Liposomal prostaglandin E1 (Lipo-PGE1) treatment should protect against hepatic warm ischemia-reperfusion injury (WIRI). Improved methods are needed for the noninvasive evaluation of hepatic responses to prophylactic Lipo-PGE1 pretreatment approaches. PURPOSE To demonstrate that multiparametric MRI measurements permit noninvasive differentiation of Lipo-PGE1 treatment outcomes in a hepatic WIRI animal model. STUDY TYPE Animal study. ANIMAL MODEL Seventy rabbits were randomly divided into a sham-operated group (A0), warm ischemia groups experiencing increasing periods of ischemia (A1-A3), and corresponding intervention groups (I1-I3) (n = 10 for each group). FIELD STRENGTH/SEQUENCE Imaging was performed at 3T using a multiecho gradient echo (GRE) sequence (repetition time / echo time [TR/TE], 75/2.57-24.25 msec) for R2* blood oxygenation level-dependent (BOLD) measurements, free-breathing single-shot echo-planar imaging (ss-EPI) sequence with two b-values (0 and 500 s/mm2 ) in 12 diffusion directions for diffusion tensor imaging (DTI), and a free-breathing ss-EPI sequence with eight b-values (0 to 800 s/mm2 ) for intravoxel incoherent motion (IVIM) measurements. ASSESSMENT The BOLD-derived parameter (R2*), DTI-derived parameters (ADC, FA), and IVIM-derived parameters (Dslow, Dfast, and PF) were calculated for comparisons between treatment groups and correlation to ALT, AST, and LDH levels. STATISTICAL TESTS One-way analysis of variance (ANOVA), independent sample t-test, Spearman correlation, and receiver operating characteristic (ROC) analysis were performed. RESULTS Histopathology confirmed the validity of the WIRI model and the efficacy of intervention with clear structure and morphology differences between the different ischemia times and between the Lipo-PGE1 treatment and control groups. Prolonged warm ischemia times resulted in higher R2* and FA values and gradually lower ADC, Dslow, Dfast, and PF values (all P

Background Reduced flow into the brain or decreased jugular venous outflow from the brain may serve as a potential biomarker for Parkinson's disease (PD). Our goal was to compare the presence of vascular abnormalities, flow, and increases in midbrain iron content (a hallmark of the disease) in patients with PD. Methods A total of 85 PD patients and 85 healthy controls (HCs) were imaged at 3T. We assessed vascular abnormalities using magnetic resonance (MR) venography, average cerebral blood flow using 2D flow quantification, and substantia nigra iron content using susceptibility mapping. Results Fifty-two percent (52%) of the PD subjects showed venous structural and functional abnormalities in the two most severe categories, while ony 14% of the HC group showed these abnormalities. Total arterial flow (tA) was significantly lower for the PD group (10.9 ± 1.8 ml/s) compared to the HCs (11.6 ± 2.1 ml/s) (t = 2.28, p = 0.02). Of the PD patients (HCs), 42% (14%) had little flow on the left side. PD patients had higher heart rates and lower perfusion and the lower perfusion correlated with increased iron content in the substantia nigra. Conclusion Some PD patients showed abnormal left internal jugular veins, lower tA, higher heart rates, and lower perfusion relative to HCs. These indicators could serve as early biomarkers for PD and create new avenues for future studies regarding the etiology of PD.

Parkinson's disease (PD) is a neurodegenerative disease with a progressive loss of mesencephalic dopaminergic neurons of the substantia nigra (SN). To further evaluate its pathophysiology, accurate animal models are needed. The current study aims to verify the impact of a 6-hydroxydopamine (6-OHDA) bilateral microinjection into the SN on gastrointestinal symptoms in rats and confirm that the 6-OHDA rat model is an appropriate tool to investigate the mechanisms of Parkinsonian GI disorders. Immunohistochemistry, digital X-ray imaging, short-circuit current, FITC-dextran permeability and ultra-performance liquid chromatography tandem mass spectrometry were used in this study. The results indicated that the dopaminergic neurons in SN and fibres in the striatum were markedly reduced in 6-OHDA rats. The 6-OHDA rats manifested reductions in occupancy in a rotarod test and increases in daily food debris but no difference in body mass or daily consumption. Compared with control rats, faecal pellets and their contents were significantly decreased, whereas gastric emptying and intestinal transport were delayed in 6-OHDA rats. The increased in vivo FITC-dextran permeability and decreased intestinal transepithelial resistance in the model suggest attenuated barrier function in the digestive tract in the PD model. Moreover, inflammatory factors in the plasma showed that pro-inflammatory factors IL-1β and IL-8 were significantly increased in 6-OHDA rats. Collectively, these findings indicate that the model is an interesting experimental tool to investigate the mechanisms involved in the progression of gastrointestinal dysfunction in PD.

The paraventricular nucleus (PVN) of the hypothalamus is an important center in regulating the functions of internal organs, and it is the key nucleus for coordinating endocrine, behavior and autonomic stress responses. Dopamine receptors are widely expressed in the hypothalamus and participate in the regulation of many vital activities, such as blood pressure and glycolipid metabolism, but the details of the cellular localization of dopamine receptors in the PVN are not clear. The present study investigated the distribution of D

We consider the optimal capital injection and dividend control problem for a class of growth restricted diffusions with the possibility of bankruptcy. The surplus process of a company is modeled by a diffusion process with return and volatility being functions of the surplus process. The company can control the dividend payments and capital injections with the goal of maximizing the expectation of the total discounted dividends minus the total cost of capital injections up to the time of bankruptcy. We distinguish three cases and provide optimality results for each case.

The equation of state (EOS) of HfC and nanosized TiC at high pressure has been studied by means of synchrotron radiation X-ray diffraction (XRD) in a diamond anvil cell (DAC) at ambient temperature, and density functional theory (DFT) calculations. XRD analysis showed that the cubic structure of HfC and nanosized TiC maintained to the maximum pressures. The XRD data yield a bulk modulus [Formula: see text] GPa with [Formula: see text] of HfC. In addition, the bulk modulus of nanosized TiC derived from XRD data is [Formula: see text] GPa with [Formula: see text].