Application of 5T glutamate chemical exchange saturation transfer imaging in brain tumors: preliminary results.

PURPOSE: Glutamate chemical exchange saturation transfer (GluCEST) is a non-invasive CEST imaging technique for detecting glutamate levels in tissues. We aimed to investigate the reproducibility of the 5T GluCEST technique in healthy volunteers and preliminarily explore its potential clinical application in patients with brain tumors. METHODS: Ten volunteers (4 males, mean age 29 years) underwent three 5T GluCEST imaging scans. The reproducibility of the three imaging GluCEST measurements was assessed using one-way repeated measures analysis of variance (ANOVA), generalized estimating equations, and linear mixed models. Twenty-eight patients with brain tumors (10 males, mean age 54 years) underwent a single GluCEST scan preoperatively, and t-tests were used to compare the differences in GluCEST values between different brain tumors. In addition, the diagnostic accuracy of GluCEST values in differentiating brain tumors was assessed using the receiver work characteristics (ROC) curve. RESULTS: The coefficients of variation of GluCEST values in healthy volunteers were less than 5% for intra-day, inter-day, and within-subjects and less than 10% for between-subjects. High-grade gliomas (HGG) had higher GluCEST values compared to low-grade gliomas (LGG) (P < 0.001). In addition, cerebellopontine angle (CPA) meningiomas had higher GluCEST values than acoustic neuromas (P < 0.001). The area under the curve (AUC) of the GluCEST value for differentiating CPA meningioma from acoustic neuroma was 0.93. CONCLUSION: 5T GluCEST images are highly reproducible in healthy brains. In addition, the 5T GluCEST technique has potential clinical applications in differentiating LGG from HGG and CPA meningiomas from acoustic neuromas.

Probiotics combined with atorvastatin administration in the treatment of hyperlipidemia: A randomized, double-blind, placebo-controlled clinical trial.

BACKGROUND: Hyperlipidemia is a common feature of chronic diseases. The aim of this work was designed to assess the role of probiotics (Lactobacillus casei Zhang, Bifidobactetium animalis subsp. lactis V9, and Lactobacillus plantarum P-8) in the treatment of hyperlipidemia. METHODS: Thirty three patients with hyperlipidemia were randomly divided into a probiotic group (n = 18) and a control group (n = 15). The probiotic group was administered probiotics (2 g once daily) and atorvastatin 20 mg (once daily), and the control group was administered a placebo (2 g once daily) and atorvastatin 20 mg (once daily). Serum and fecal samples were gathered for subsequent analyses. RESULTS: Time had a significant effect on the total cholesterol (TC), triglycerides (TG), and low-density lipoprotein-cholesterol (LDL-C) levels in the probiotic and control groups (P < .05). The gut microbial abundance in the probiotic group was markedly higher than that in the control group following 3-month probiotic treatment (P < .05). At the phylum level, probiotics exerted no notable effects on the relative abundance of Firmicutes, Bacteroidetes, and Actinobacteria but elevated that of Tenericutes and reduced Proteobacteria. At the genus level, probiotics increased the relative abundance of Bifidobacterium, Lactobacillus, and Akkermansia, and decreased that of Escherichia, Eggerthella, and Sutterella relative to the control group in months 1, 2, and 3 (P < .05). CONCLUSIONS: Probiotics optimize the gut microbiota structure and decrease the amount of harmful bacteria in patients with hyperlipidemia. Probiotics can influence the composition of gut microorganisms and increase their diversity and abundance in vivo. It is recommended to use probiotics combined with atorvastatin to treat patients with hyperlipidemia.

The feasibility of half-dose contrast-enhanced scanning of brain tumours at 5.0 T: a preliminary study.

PURPOSE: This study investigated and compared the effects of Gd enhancement on brain tumours with a half-dose of contrast medium at 5.0 T and with a full dose at 3.0 T. METHODS: Twelve subjects diagnosed with brain tumours were included in this study and underwent MRI after contrast agent injection at 3.0 T (full dose) or 5.0 T (half dose) with a 3D T1-weighted gradient echo sequence. The postcontrast images were compared by two independent neuroradiologists in terms of the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and subjective image quality score on a ten-point Likert scale. Quantitative indices and subjective quality ratings were compared with paired Student's t tests, and interreader agreement was assessed with the intraclass correlation coefficient (ICC). RESULTS: A total of 16 enhanced tumour lesions were detected. The SNR was significantly greater at 5.0 T than at 3.0 T in grey matter, white matter and enhanced lesions (p < 0.001). The CNR was also significantly greater at 5.0 T than at 3.0 T for grey matter/tumour lesions, white matter/tumour lesions, and grey matter/white matter (p < 0.001). Subjective evaluation revealed that the internal structure and outline of the tumour lesions were more clearly displayed with a half-dose at 5.0 T (Likert scale 8.1 ± 0.3 at 3.0 T, 8.9 ± 0.3 at 5.0 T, p < 0.001), and the effects of enhancement in the lesions were comparable to those with a full dose at 3.0 T (7.8 ± 0.3 at 3.0 T, 8.7 ± 0.4 at 5.0 T, p < 0.001). All subjective scores were good to excellent at both 5.0 T and 3.0 T. CONCLUSION: Both quantitative and subjective evaluation parameters suggested that half-dose enhanced scanning via 5.0 T MRI might be feasible for meeting clinical diagnostic requirements, as the image quality remains optimal. Enhanced scanning at 5.0 T with a half-dose of contrast agents might benefit patients with conditions that require less intravenous contrast agent, such as renal dysfunction.

ML241 Antagonizes ERK 1/2 Activation and Inhibits Rotavirus Proliferation.

Rotavirus (RV) is the main pathogen that causes severe diarrhea in infants and children under 5 years of age. No specific antiviral therapies or licensed anti-rotavirus drugs are available. It is crucial to develop effective and low-toxicity anti-rotavirus small-molecule drugs that act on novel host targets. In this study, a new anti-rotavirus compound was selected by ELISA, and cell activity was detected from 453 small-molecule compounds. The anti-RV effects and underlying mechanisms of the screened compounds were explored. In vitro experimental results showed that the small-molecule compound ML241 has a good effect on inhibiting rotavirus proliferation and has low cytotoxicity during the virus adsorption, cell entry, and replication stages. In addition to its in vitro effects, ML241 also exerted anti-RV effects in a suckling mouse model. Transcriptome sequencing was performed after adding ML241 to cells infected with RV. The results showed that ML241 inhibited the phosphorylation of ERK1/2 in the MAPK signaling pathway, thereby inhibiting IκBα, activating the NF-κB signaling pathway, and playing an anti-RV role. These results provide an experimental basis for specific anti-RV small-molecule compounds or compound combinations, which is beneficial for the development of anti-RV drugs.

Quantifying H&E staining results, grading and predicting IDH mutation status of gliomas using hybrid multi-dimensional MRI.

OBJECTIVE: To assess the performance of hybrid multi-dimensional magnetic resonance imaging (HM-MRI) in quantifying hematoxylin and eosin (H&E) staining results, grading and predicting isocitrate dehydrogenase (IDH) mutation status of gliomas. MATERIALS AND METHODS: Included were 71 glioma patients (mean age, 50.17 ± 13.38 years; 35 men). HM-MRI images were collected at five different echo times (80-200 ms) with seven b-values (0-3000 s/mm2). A modified three-compartment model with very-slow, slow and fast diffusion components was applied to calculate HM-MRI metrics, including fractions, diffusion coefficients and T2 values of each component. Pearson correlation analysis was performed between HM-MRI derived fractions and H&E staining derived percentages. HM-MRI metrics were compared between high-grade and low-grade gliomas, and between IDH-wild and IDH-mutant gliomas. Using receiver operational characteristic (ROC) analysis, the diagnostic performance of HM-MRI in grading and genotyping was compared with mono-exponential models. RESULTS: HM-MRI metrics FDvery-slow and FDslow demonstrated a significant correlation with the H&E staining results (p < .05). Besides, FDvery-slow showed the highest area under ROC curve (AUC = 0.854) for grading, while Dslow showed the highest AUC (0.845) for genotyping. Furthermore, a combination of HM-MRI metrics FDvery-slow and T2Dslow improved the diagnostic performance for grading (AUC = 0.876). DISCUSSION: HM-MRI can aid in non-invasive diagnosis of gliomas.

Improved Detection of Target Metabolites in Brain Tumors with Intermediate TE, High SNR, and High Bandwidth Spin-Echo Sequence at 5T.

BACKGROUND AND PURPOSE: Due to high chemical shift displacement, challenges emerge at ultra-high fields when measuring metabolites using 1H-MRS. Our goal was to investigate how well the high SNR and high bandwidth spin-echo (HISE) technique perform at 5T for detecting target metabolites in brain tumors. MATERIALS AND METHODS: Twenty-six subjects suspected of having brain tumors were enrolled. HISE and point-resolved spectroscopy (PRESS) single-voxel spectroscopy scans were collected with a 5T clinical scanner with an intermediate TE (TE = 144 ms). The main metabolites, including total NAA, Cr, and total Cho, were accessed and compared between HISE and PRESS using a paired Student t test, with full width at half maximum and SNR as covariates. The detection rate of specific metabolites, including lactate, alanine, and lipid, and subjective spectral quality were accessed and compared between HISE and PRESS. RESULTS: Twenty-three pathologically confirmed brain tumors were included. Only the full width at half maximum for total NAA was significantly lower with HISE than with PRESS (P < .05). HISE showed a significantly higher SNR for total NAA, Cr, and total Cho compared with PRESS (P < .05). Lactate was detected in 21 of the 23 cases using HISE, but in only 4 cases using PRESS. HISE detected alanine in 8 of 9 meningiomas, whereas PRESS detected alanine in just 3 meningiomas. PRESS found lipid in more cases than HISE, while HISE outperformed PRESS in terms of subjective spectral quality. CONCLUSIONS: HISE outperformed the clinical standard PRESS technique in detecting target metabolites of brain tumors at 5T, particularly lactate and alanine.

Safety, Immunogenicity, and Mechanism of a Rotavirus mRNA-LNP Vaccine in Mice.

Rotaviruses (RVs) are a major cause of diarrhea in young children worldwide. The currently available and licensed vaccines contain live attenuated RVs. Optimization of live attenuated RV vaccines or developing non-replicating RV (e.g., mRNA) vaccines is crucial for reducing the morbidity and mortality from RV infections. Herein, a nucleoside-modified mRNA vaccine encapsulated in lipid nanoparticles (LNP) and encoding the VP7 protein from the G1 type of RV was developed. The 5' untranslated region of an isolated human RV was utilized for the mRNA vaccine. After undergoing quality inspection, the VP7-mRNA vaccine was injected by subcutaneous or intramuscular routes into mice. Mice received three injections in 21 d intervals. IgG antibodies, neutralizing antibodies, cellular immunity, and gene expression from peripheral blood mononuclear cells were evaluated. Significant differences in levels of IgG antibodies were not observed in groups with adjuvant but were observed in groups without adjuvant. The vaccine without adjuvant induced the highest antibody titers after intramuscular injection. The vaccine elicited a potent antiviral immune response characterized by antiviral clusters of differentiation CD8+ T cells. VP7-mRNA induced interferon-γ secretion to mediate cellular immune responses. Chemokine-mediated signaling pathways and immune response were activated by VP7-mRNA vaccine injection. The mRNA LNP vaccine will require testing for protective efficacy, and it is an option for preventing rotavirus infection.

Study on the electrodeposition of uranium in chloride molten salt.

This study focuses on the recovery of UO2 from oxide spent fuel using electrodeposition. U3O8 was used as the initial material and dissolved in NaCl-2CsCl using NH4Cl at high temperatures by means of chlorination reaction. The electrolysis process was conducted using a three-electrode system to investigate the effects of cathode material and diameter, electrolysis temperature, electrolysis time, electrolysis voltage, and uranium concentration in the molten salt on the electrolysis reaction. By optimizing the electrolysis conditions, pure UO2 with a recovery efficiency of 97% was obtained, and the products were characterized using XRD, SEM-EDS, ICP-AES and XPS. It was found that within the scope of this experiment, increasing the cathode diameter, extending the electrolysis time, and increasing the reduction voltage appropriately all led to an improvement in the recovery efficiency of the electrolysis reaction, while other conditions had minimal effect on the reaction. Furthermore, doping of the electrolyte system was performed by adding La, Ce and Nd elements, while the removal of La showed good purification effects, with a maximum decontamination factor of 119. Furthermore, the system showed good purification effects for Nd, with a decontamination factor of 57.

Characterizing cerebrospinal fluid mobility using heavily T2-weighted 3D fast spin echo (FSE) imaging with improved multi-directional diffusion-sensitized driven-equilibrium (iMDDSDE) preparation.

Cerebrospinal fluid (CSF) flow patterns and their relationship with arterial pulsation can depict the function of glymphatic system (GS). We propose an improved multi-directional diffusion-sensitized driven-equilibrium (iMDDSDE) prepared heavily T2-weighted 3D FSE (iMDDSDE-HT2) magnetic resonance imaging (MRI) method to noninvasively assess the mobility (MO) of CSF distributed in the ventricles and perivascular spaces (PVS). This method could obtain 3D high resolution (1 mm isotropic) imaging of CSF MO with full brain coverage within five min and distinguish the CSF MO across different pulse phases using a peripheral pulse unit (PPU). The MO curves had the largest amplitude value in the PVS of middle cerebral artery (11.11 × 10-9 m2/s) and the largest amplitude growth rate in the posterior cerebral artery (189%). The average coefficient of variations (CVs) in non-pulse trigger and pulse phase 1 and 3 were 0.11, 0.10 and 0.09 respectively. The MO in older healthy participants was lower compared to the young participants, and the MO in cerebral major artery stenosis patients with acute ischemia stroke (AIS) were lower compared to those without AIS in several ventriclar ROIs (P < 0.05). This sequence is a clinically feasible method to effectively evaluate CSF flow patterns in human brain.

Disturbed meningeal lymphatic function associated with malignancy and progression in patients with intracranial malignant tumors.

BACKGROUND: Meningeal lymphatic vessels (mLVs) have proven to bear a relationship with tumor immunity and therapeutic efficacy of intracranial malignant tumors in pre-clinical animal studies. We aimed to explore the association between mLV function and intracranial malignant tumors in clinical participants. METHODS: The participants were allocated to a control group or a group of patients with intracranial tumors. Dynamic enhanced magnetic resonance was used to evaluate the wash-in and wash-out functions of mLVs around the superior sagittal sinus and the sigmoid sinus. FINDINGS: A total of 246 individuals were recruited for our study. The area under curve and wash-in rate of mLVs in the intracranial tumor group were higher than in the control group (2,749 vs. 2,110, p < 0.001 and 3.72 vs. 2.87, p < 0.001, respectively). The wash-out ratio of mLVs was lower in the intracranial tumor group than in the control group (0.65 vs. 0.73, p < 0.001). Decreased wash-out of mLVs was associated with tumor progression (ß = -0.118; p < 0.001). High-grade glioma and isocitrate dehydrogenase wild type were associated with a lower mLV wash-out function (ß = -0.057, p = 0.044 and ß = -0.069, p = 0.047, respectively). CONCLUSIONS: Intracranial malignant tumors were associated with elevated wash-in function and decreased wash-out function of mLVs. High-grade glioma and isocitrate dehydrogenase wild type were associated with low mLV wash-out function, and long-term decreased mLV wash-out function was a risk factor for tumor progression. FUNDING: There was no funding.

Oleanolic acid, a small-molecule natural product, inhibits ECM degeneration in osteoarthritis by regulating the Hippo/YAP and Wnt/ß-catenin pathways.

Over the past few decades, osteoarthritis (OA) has been a major health problem worldwide. It is urgent to develop new, effective, and safe drugs to treat OA. There are many pentacyclic triterpenoids in nature that are safe and have health benefits. Oleanolic acid (OLA), one of the pentacyclic triterpenoids, is a potential novel compound for treating OA; however, its mechanism of action is still unclear. In this study, the mechanism of resistance to extracellular matrix (ECM) degradation of OLA and its protective role in the amelioration of OA were investigated by in vivo and in vitro experiments. We found that OLA promoted interleukin-1ß (IL-1ß)-induced production of type II collagen (collagen II) in rat chondrocytes, decreased the expression of matrix metalloproteinase (MMP)-3 and MMP-13, and inhibited inflammatory cytokine (IL-1ß and TNF-α) and cartilage marker (CTX-II and COMP) levels, thereby hindering the pathological process of cartilage. Mechanistically, OLA inhibited the Wnt/ß-catenin pathway, activated the Hippo/YAP pathway, and hampered the ECM degradation process by inhibiting the nuclear translocation of ß-catenin and YAP. When we knocked down ß-catenin, OLA lost its stimulatory effect on the Hippo pathway. These findings confirm that OLA plays an anti-ECM degradation role by regulating the Wnt/ß-catenin and Hippo/YAP pathways. Overall, this study provides a theoretical basis for developing highly effective and low-toxic natural products for the prevention and treatment of OA.

Mesenchymal stromal cell biotherapy for Parkinson's disease premotor symptoms.

Parkinson's disease (PD) is a neurodegenerative disorder with motor deficits due to nigrostriatal dopamine depletion and with the non-motor/premotor symptoms (NMS) such as anxiety, cognitive dysfunction, depression, hyposmia, and sleep disorders. NMS is presented in at least one-fifth of the patients with PD. With the histological information being investigated, stem cells are shown to provide neurotrophic supports and cellular replacement in the damaging brain areas under PD conditions. Pathological change of progressive PD includes degeneration and loss of dopaminergic neurons in the substantia nigra of the midbrain. The current stem cell beneficial effect addresses dopamine boost for the striatal neurons and gliovascular mechanisms as competing for validated PD drug targets. In addition, there are clinical interventions for improving the patient's NMS and targeting their autonomic dysfunction, dementia, mood disorders, or sleep problems. In our and many others' research using brain injury models, multipotent mesenchymal stromal cells demonstrate an additional and unique ability to alleviate depressive-like behaviors, independent of an accelerated motor recovery. Intranasal delivery of the stem cells is discussed for it is extensively tested in rodent animal models of neurological and psychiatric disorders. In this review, we attempt to discuss the repairing potentials of transplanted cells into parkinsonism pathological regions of motor deficits and focus on preventive and treatment effects. From new approaches in the PD biological therapy, it is believed that it can as well benefit patients against PD-NMS.

Functional abnormalities of the cerebellum in vascular mild cognitive impairment.

OBJECTIVES: The alterations in cerebellar activity that occur in vascular mild cognitive impairment remain largely unexplored. This study aimed to investigate potential associations between abnormal cerebellar functional connectivity (FC) and changes in cognitive function by examining intracerebellar and cerebellar-cerebral FC. METHODS: MRI data were collected from seventy-two patients with vascular mild cognitive impairment (VMCI), comprising 38 patients with small vessel mild cognitive impairment (SVMCI) and 34 with poststroke mild cognitive impairment (PSMCI), and from 43 demographically matched healthy controls (HCs). Changes in FC between subregions within the cerebellum and from each cerebellar subregion to the selected cerebral seed points in VMCI patients were calculated, and the association of these changes with cognitive function was examined. RESULTS: Compared with HCs, we found that VMCI patients had 11 cerebellar subregions showing significant differences (mainly decreases) in FC with brain regions in the default-mode network (DMN), sensory-motor network (SMN), and frontoparietal network (FPN). In the intracerebellar FC analysis, 47 (8%) cerebellar connections had significant intergroup differences, mainly a reduced magnitude of FC in VMCI patients. In the correlation analysis, higher Montreal Cognitive Assessment (MoCA) scores were correlated with stronger intracerebellar FC (left crus II-right lobule VI, left crus II-right lobule VIIb) and cerebellar-cerebral FC (right lobule X-left precuneus, vermal lobule IX-right inferior parietal lobule) in both the SVMCI and PSMCI groups. CONCLUSION: These findings suggest prominent intracerebellar and cerebellar-cerebral FC abnormalities in VMCI patients, contributing evidence for a possible role of the cerebellum in cognitive processes.

Stability and repeatability of diffusion-weighted imaging (DWI) of normal pancreas on 5.0 Tesla magnetic resonance imaging (MRI).

To explore the stability and repeatability of diffusion-weighted imaging (DWI) of normal pancreas with different field of views (FOV) on 5.0 T magnetic resonance imaging (MRI) system. Twenty healthy subjects underwent two sessions of large FOV (lFOV) and reduced FOV (rFOV) DWI sequence scanning. Two radiologists measured the apparent diffusion coefficient (ADC) values and the signal-to-noise ratio (SNR) of the pancreatic head, body, and tail on DWI images, simultaneously, using a 5-point scale, evaluate the artifacts and image quality. One radiologist re-measured the ADC on DWI images again after a 4-week interval. The test-retest repeatability of two scan sessions were also evaluated. Intra-observer and inter-observer at lFOV and rFOV, the ADC values were not significantly different (P > 0.05), intraclass correlation coefficients (ICCs) and coefficient of variations were excellence (ICCs 0.85-0.99, CVs < 8.0%). The ADC values were lower with rFOV than lFOV DWI for the head, body, tail, and overall pancreas. The consistency of the two scan sessions were high. The high stability and repeatability of pancreas DWI has been confirmed at 5.0 T. Scan durations are reduced while resolution and image quality are improved with rFOV DWI, which is more preferable than lFOV for routine pancreas imaging.

Geochemical fractionation, bioaccessibility and ecological risk of metallic elements in the weathering profiles of typical skarn-type copper tailings from Tongling, China.

Nonferrous metal tailings have long posed a significant threat to the surrounding environment and population. Previous studies have primarily focused on heavy metal pollution in the vicinity of sulfide tailings, while little attention was given to metal mobility and bioavailability within skarn-type tailings profile during weathering. Therefore, this study aimed to investigate the fractionation, bioaccessibility, and ecological risk associated with metallic elements (MEs, including Pb, Cd, Cr, Zn, and Cu) in two representative weathering copper-tailings profiles of Tongling mine (China). This was achieved through the use of mineralogical analyses, BCR extractions (F1: exchangeable, F2: reducible, F3: oxidizable, F4: residual fraction), in-vitro gastrointestinal simulation test (PBET) and risk assessment models. The mineral compositions of two weathering profiles were similar, with quartz and calcite being the dominant minerals, along with minor amounts of siderite, hematite and spangolite. The mean concentration in the tailings profile was approximately 0.31 (Cr), 1.8 (Pb), 12 (Zn), 33 (Cd) or 34 (Cu) times of the local background values (LBVs). The mean content of the bottom weakly-weathering layer in profile was about 0.36 (Cr), 0.91 (Pb), 1.91 (Cd), 2.73 (Zn) or 2.68 (Cu) times of the surface oxide layer, indicating a strong weathering-leaching effect. The average proportion of BCR-F1 fraction for Cd (30.94 %) was the highest among the five MEs, possibly due to its association with calcite. The PBET-extracted fractions for Cd, Zn and Cu were significantly positively correlated with the F1, F2 and F3 fractions of BCR, suggesting that these elements have higher bioavailability/bioaccessibility. The assessment results indicated that Cd posed a higher health risk, while the risk of Cu, Zn, and Pb is relatively low and Cr is safe. In conclusion, this study provides valuable insights into the environmental geochemical behavior and potential risks of MEs in skarn-type non-ferrous metal tailings ponds.

A unified hybrid transformer for joint MRI sequences super-resolution and missing data imputation.

Objective.High-resolution multi-modal magnetic resonance imaging (MRI) is crucial in clinical practice for accurate diagnosis and treatment. However, challenges such as budget constraints, potential contrast agent deposition, and image corruption often limit the acquisition of multiple sequences from a single patient. Therefore, the development of novel methods to reconstruct under-sampled images and synthesize missing sequences is crucial for clinical and research applications.Approach. In this paper, we propose a unified hybrid framework called SIFormer, which utilizes any available low-resolution MRI contrast configurations to complete super-resolution (SR) of poor-quality MR images and impute missing sequences simultaneously in one forward process. SIFormer consists of a hybrid generator and a convolution-based discriminator. The generator incorporates two key blocks. First, the dual branch attention block combines the long-range dependency building capability of the transformer with the high-frequency local information capture capability of the convolutional neural network in a channel-wise split manner. Second, we introduce a learnable gating adaptation multi-layer perception in the feed-forward block to optimize information transmission efficiently.Main results. Comparative evaluations against six state-of-the-art methods demonstrate that SIFormer achieves enhanced quantitative performance and produces more visually pleasing results for image SR and synthesis tasks across multiple datasets.Significance. Extensive experiments conducted on multi-center multi-contrast MRI datasets, including both healthy individuals and brain tumor patients, highlight the potential of our proposed method to serve as a valuable supplement to MRI sequence acquisition in clinical and research settings.

The Aging Behavior and Life Prediction of CFRP Rods under a Hygrothermal Environment.

Carbon fiber-reinforced polymer (CFRP) composites have been widely used in civil engineering structures due to their excellent mechanical and durability properties. The harsh service environment of civil engineering leads to significant degradation of the thermal and mechanical performances of CFRP, which then reduces its service reliability, service safety, and life. Research on the durability of CFRP is urgently needed to understand the long-term performance degradation mechanism. In the present study, the hygrothermal aging behavior of CFRP rods was investigated experimentally through immersion in distilled water for 360 days. The water absorption and diffusion behavior, the evolution rules of short beam shear strength (SBSS), and dynamic thermal mechanical properties were obtained to investigate the hygrothermal resistance of CFRP rods. The research results show that the water absorption behavior conforms to Fick's model. The ingression of water molecules leads to a significant decrease in SBSS and glass transition temperature (Tg). This is attributed to the plasticization effect of the resin matrix and interfacial debonding. Furthermore, the Arrhenius equation was used to predict the long-term life of SBSS in the actual service environment based on the time-temperature equivalence theory, obtaining a stable strength retention of SBSS of 72.78%, which was meaningful to provide a design guideline for the long-term durability of CFRP rods.

More than one quarter of Africa's tree cover is found outside areas previously classified as forest.

The consistent monitoring of trees both inside and outside of forests is key to sustainable land management. Current monitoring systems either ignore trees outside forests or are too expensive to be applied consistently across countries on a repeated basis. Here we use the PlanetScope nanosatellite constellation, which delivers global very high-resolution daily imagery, to map both forest and non-forest tree cover for continental Africa using images from a single year. Our prototype map of 2019 (RMSE = 9.57%, bias = -6.9%). demonstrates that a precise assessment of all tree-based ecosystems is possible at continental scale, and reveals that 29% of tree cover is found outside areas previously classified as tree cover in state-of-the-art maps, such as in croplands and grassland. Such accurate mapping of tree cover down to the level of individual trees and consistent among countries has the potential to redefine land use impacts in non-forest landscapes, move beyond the need for forest definitions, and build the basis for natural climate solutions and tree-related studies.

The Long-Term Interfacial Evolution and Prediction of Carbon- and Glass-Fiber-Reinforced Epoxy Hybrid Rods under a Hygrothermal Environment.

In order to promote the engineering applications of carbon- and glass-fiber-reinforced epoxy hybrid rods, it is necessary to fully understand its long-term hygrothermal durability. In the present study, the water absorption behaviors of a hybrid rod in a water immersion environment are studied experimentally, the degradation rules of the mechanical properties are obtained, and establishing a life prediction model is attempted. The water absorption of the hybrid rod confirms to the classical Fick's diffusion model, and the water absorption concentration is determined by radial position, immersion temperature, and immersion time. In addition, the radial position of water molecules diffused into the rod is positively correlated with the diffusion concentration. The short-beam shear strength of the hybrid rod decreased significantly after 360 days of exposure; this is because water molecules interact with the polymer through hydrogen bonds to produce bound water during the immersion process, leading to resin matrix hydrolysis and plasticization, as well as interfacial debonding. In addition, the ingression of water molecules caused degradation in the viscoelastic behavior of the resin matrix in hybrid rods. The glass transition temperature of hybrid rods decreased by 17.4% after exposure at 80 °C for 360 days. The Arrhenius equation was used calculate the long-term life of short-beam shear strength in the actual service temperature based on the time-temperature equivalence theory. The stable strength retention for SBSS was found to be 69.38%, which is a useful durability design parameter for hybrid rods in civil engineering structures.

The disruption of white matter integrity of systemic striatal circuits in alcohol-dependent males with physiological cue reactivity.

Alcohol dependence (AD) is a chronic and relapsing disorder. Conditioned cues associated with the rewarding properties of drugs could trigger motivational/physiological reactions and render subjects vulnerable to relapse. Striatal circuit dysfunction has been implicated in alcohol addiction behaviours. However, little is known about the striatal tracts structural connectivity changes underlying cue induced reactivity in AD. In our present study, we recruited 51 patients with AD; 31 individuals had physiological response. We used seed-based classification by probabilistic tractography with nine target masks to explore the white matter integrity of striatal circuits in physiological responders (N = 31), non-responders (N = 20), and healthy controls (N = 27). Compared with healthy controls, physiological responders showed lower fractional anisotropy (FA) and/or higher mean diffusivity in the striatum-dorsolateral prefrontal cortex (dlPFC), striatum-ventral lateral prefrontal cortex, striatum-supplementary motor area (SMA), and striatum-insular. Considering age and smoking are potential nuisances to diffusion parameters, an analysis of covariance also was conducted and similar results were found. We also found the cue-induced physiological response was negatively associated with the FA of the striatum-SMA (r = -0.287; p = 0.045) and left striatum-dlPFC (r = -0.253; p = 0.079) in AD. In our study, we found abnormal integrity of striatal circuit structural connectivity in AD with physiological cue reactivity, especially trajectory from prefrontal cortex and insular. We also found the FA of striatal tracks was negatively associated with the degree of cue reactivity. Our findings provide further evidence for reduced white matter integrity of striatal circuits for cue reactivity in male individuals with AD.