A motion assessment method for reference stack selection in fetal brain MRI reconstruction based on tensor rank approximation.

Slice-to-volume registration and super-resolution reconstruction are commonly used to generate 3D volumes of the fetal brain from 2D stacks of slices acquired in multiple orientations. A critical initial step in this pipeline is to select one stack with the minimum motion among all input stacks as a reference for registration. An accurate and unbiased motion assessment (MA) is thus crucial for successful selection. Here, we presented an MA method that determines the minimum motion stack based on 3D low-rank approximation using CANDECOMP/PARAFAC (CP) decomposition. Compared to the current 2D singular value decomposition (SVD) based method that requires flattening stacks into matrices to obtain ranks, in which the spatial information is lost, the CP-based method can factorize 3D stack into low-rank and sparse components in a computationally efficient manner. The difference between the original stack and its low-rank approximation was proposed as the motion indicator. Experiments on linearly and randomly simulated motion illustrated that CP demonstrated higher sensitivity in detecting small motion with a lower baseline bias, and achieved a higher assessment accuracy of 95.45% in identifying the minimum motion stack, compared to the SVD-based method with 58.18%. CP also showed superior motion assessment capabilities in real-data evaluations. Additionally, combining CP with the existing SRR-SVR pipeline significantly improved 3D volume reconstruction. The results indicated that our proposed CP showed superior performance compared to SVD-based methods with higher sensitivity to motion, assessment accuracy, and lower baseline bias, and can be used as a prior step to improve fetal brain reconstruction.

Enhanced fluorescence properties of polyfluorene-based polymer dots through an ascorbic acid-photoaging treatment for living cell imaging.

The polymer dots (Pdots) prepared by the conjugated polymer (PFO, poly (9,9-dihexylfluorene-2,7-diyl)) have high fluorescence intensity and are often used in biological fluorescence imaging. However, due to the chain defects, the PFO Pdots suffer from stability issues such as photoinactivation and photobleaching. To solve this problem, we drew inspiration from the preparation process of organic planar light-emitting devices and added an optimization processing after Pdots was prepared. We used illumination as the driving force to activate defects on its chain, and ascorbic acid as a reducing substance to restore the chain defects of the polymer to a more stable state. Through this method, we increased the fluorescence intensity by nearly 1.9 times, and significantly improving their long and short-term stability. In addition, it ensures other properties remain unchanged. This optimization scheme is also fully compatible with the entire biological imaging process, ensuring that other important properties such as cytotoxicity do not undergo unnecessary changes. Furthermore, we conducted material characterization and theoretical simulation, revealing that the optimization scheme mainly serves to repair C-9 alkyl defects on the polyfluorene unit. This study has improved and enhanced the fluorescence performance of PFO Pdots, and also provides a way to optimize the treatment of other similar conjugated polymer material systems.

Development of the Fetal Brain Corticocortical Structural Network during the Second-to-Third Trimester Based on Diffusion MRI.

During the second-to-third trimester, the neuronal pathways of the fetal brain experience rapid development, resulting in the complex architecture of the interwired network at birth. While diffusion MRI-based tractography has been employed to study the prenatal development of structural connectivity network (SCN) in preterm neonatal and postmortem fetal brains, the in utero development of SCN in the normal fetal brain remains largely unknown. In this study, we utilized in utero dMRI data from human fetuses of both sexes between 26 and 38 gestational weeks to investigate the developmental trajectories of the fetal brain SCN, focusing on intrahemispheric connections. Our analysis revealed significant increases in global efficiency, mean local efficiency, and clustering coefficient, along with significant decrease in shortest path length, while small-worldness persisted during the studied period, revealing balanced network integration and segregation. Widespread short-ranged connectivity strengthened significantly. The nodal strength developed in a posterior-to-anterior and medial-to-lateral order, reflecting a spatiotemporal gradient in cortical network connectivity development. Moreover, we observed distinct lateralization patterns in the fetal brain SCN. Globally, there was a leftward lateralization in network efficiency, clustering coefficient, and small-worldness. The regional lateralization patterns in most language, motor, and visual-related areas were consistent with prior knowledge, except for Wernicke's area, indicating lateralized brain wiring is an innate property of the human brain starting from the fetal period. Our findings provided a comprehensive view of the development of the fetal brain SCN and its lateralization, as a normative template that may be used to characterize atypical development.

A Shape-Restorable hierarchical polymer membrane composite system for enhanced antibacterial and antiadhesive efficiency.

Intelligent shape memory polymer can be potentially used in manufacturing implantable devices that enables a benign variation of implant dimensions with the external stimuli, thus effectively lowering insertion forces and evading associated risks. However, in surgical implantation, biomaterials-associated infection has imposed a huge burden to healthcare system that urgently requires an efficacious replacement of antibiotic usages. Preventing the initial attachment and harvesting a biocidal function upon native surfaces may be deemed as a preferable strategy to tackle the issues of bacterial infection. Herein, a functionalized polylactic acid (PLA) composite membrane assembled with graphene (GE, a widely used photothermal agent) was fabricated through a blending process and then polydimethylsiloxane utilized as binders to pack hydrophobic SiO2 tightly onto polymer surface (denoted as PLA-GE/SiO2). Such an active platform exhibited a moderate shape-memory performance upon near-infrared (NIR) light stimulation, which was feasible for programmed deformation and shape recovery. Particularly stirring was that PLA-GE/SiO2 exerted a pronounced bacteria-killing effect under NIR illumination, 99.9 % of E. coli and 99.8 % of S. aureus were effectively eradicated in a lean period of 5 min. Furthermore, the obtained composite membrane manifested excellent antiadhesive properties, resulting in a bacteria-repelling efficacy of up to 99 % for both E. coli and S. aureus species. These findings demonstrated the potential value of PLA-GE/SiO2 as a shape-restorable platform in "kill&repel" integration strategy, further expanding its applications for clinical anti-infective treatment.

Metabolite T1 relaxation times decrease across the adult lifespan.

Relaxation correction is an integral step in quantifying brain metabolite concentrations measured by in vivo magnetic resonance spectroscopy (MRS). While most quantification routines assume constant T1 relaxation across age, it is possible that aging alters T1 relaxation rates, as is seen for T2 relaxation. Here, we investigate the age dependence of metabolite T1 relaxation times at 3 T in both gray- and white-matter-rich voxels using publicly available metabolite and metabolite-nulled (single inversion recovery TI = 600 ms) spectra acquired at 3 T using Point RESolved Spectroscopy (PRESS) localization. Data were acquired from voxels in the posterior cingulate cortex (PCC) and centrum semiovale (CSO) in 102 healthy volunteers across 5 decades of life (aged 20-69 years). All spectra were analyzed in Osprey v.2.4.0. To estimate T1 relaxation times for total N-acetyl aspartate at 2.0 ppm (tNAA2.0) and total creatine at 3.0 ppm (tCr3.0), the ratio of modeled metabolite residual amplitudes in the metabolite-nulled spectrum to the full metabolite signal was calculated using the single-inversion-recovery signal equation. Correlations between T1 and subject age were evaluated. Spearman correlations revealed that estimated T1 relaxation times of tNAA2.0 (rs = -0.27; p < 0.006) and tCr3.0 (rs = -0.40; p < 0.001) decreased significantly with age in white-matter-rich CSO, and less steeply for tNAA2.0 (rs = -0.228; p = 0.005) and (not significantly for) tCr3.0 (rs = -0.13; p = 0.196) in graymatter-rich PCC. The analysis harnessed a large publicly available cross-sectional dataset to test an important hypothesis, that metabolite T1 relaxation times change with age. This preliminary study stresses the importance of further work to measure age-normed metabolite T1 relaxation times for accurate quantification of metabolite levels in studies of aging.

Recent advances in biological molecule detection based on a three-dimensional graphene structure.

Graphene has become an attractive material in the field of electrochemical detection owing to its unique electrical properties. Although the simple stacking structures of two-dimensional (2D) graphene sheets can provide excellent detection properties, a macroscopic three-dimensional (3D) structure needs to be constructed to enhance its functional properties. Graphene with a 3D structure has elegant functions, unlike graphene with a 2D structure. These properties include a large specific surface area, easy loading of nanomaterials with electrocatalytic and redox functions, and so on. Herein, we outline the preparation methods (self-assembly, chemical vapor deposition, templates, and 3D printing) for 3D graphene structures for obtaining excellent detection performance and applications in detecting biological molecules, bacteria, and cells. Furthermore, this review focuses on the improvement of the detection performance and enhancement of the applicability of graphene-based electrochemical sensors. We hope that this article will provide a reference for the future development of electrochemical sensors based on 3D graphene composites.

Regional GABA levels modulate abnormal resting-state network functional connectivity and cognitive impairment in multiple sclerosis.

More evidence shows that changes in functional connectivity with regard to brain networks and neurometabolite levels correlated to cognitive impairment in multiple sclerosis. However, the neurological basis underlying the relationship among neurometabolite levels, functional connectivity, and cognitive impairment remains unclear. For this purpose, we used a combination of magnetic resonance spectroscopy and resting-state functional magnetic resonance imaging to study gamma-aminobutyric acid and glutamate concentrations in the posterior cingulate cortex, medial prefrontal cortex and left hippocampus, and inter-network functional connectivity in 29 relapsing-remitting multiple sclerosis patients and 34 matched healthy controls. Neuropsychological tests were used to evaluate the cognitive function. We found that relapsing-remitting multiple sclerosis patients demonstrated significantly reduced gamma-aminobutyric acid and glutamate concentrations and aberrant functional connectivity involving cognitive-related networks compared to healthy controls, and both alterations were associated with specific cognition decline. Moreover, mediation analyses indicated that decremented hippocampus gamma-aminobutyric acid levels in relapsing-remitting multiple sclerosis patients mediated the association between inter-network functional connectivity in various components of default mode network and verbal memory deficits. In summary, our findings shed new lights on the essential function of GABAergic system abnormalities in regulating network dysconnectivity and functional connectivity in relapsing-remitting multiple sclerosis patients, suggesting potential novel approach to treatment.

Reproducibility of Diffusion MRI-Based Tractography in the Fetal Brain.

BACKGROUND: Tractography based on diffusion MRI (dMRI) is a useful tool to study white matter of the developing brain. However, its application in fetal brains is limited due to motion artifacts and low resolution of in utero dMRI, leading to reduced reliability, which was scarcely investigated in previous studies. PURPOSE: To identify reliably traceable fibers in fetal brains and assess whether reproducibility varies with gestational age (GA) and varies between brain regions. STUDY TYPE: Prospective cohort study. SUBJECTS: A total of 44 healthy fetuses with GAs between 25 and 37 (31 ± 6). FIELD STRENGTH/SEQUENCE: 3-T, diffusion-weighted echo-planar imaging sequence (2-5 repeated dMRI scans within the same session per subject). ASSESSMENT: We fitted dMRI with constrained spherical deconvolution model and conducted tractography on eight fibers. We extracted volume, fractional anisotropy, and fiber count for each fiber and assessed the reproducibility of these metrics between repeated scans within each subject. Data were divided into two age-based subgroups (≤30 weeks, N = 28, and >30 weeks, N = 16) for further tests. STATISTICAL TESTS: The reproducibility were compared between fibers by analysis of variance and two-sample t tests. Multiple comparisons were corrected by the false discovery rate (5% was accepted). RESULTS: The reproducibility of the anterior thalamic radiation, inferior longitudinal fasciculus (ILF), genu of the corpus callosum (GCC), and body of the corpus callosum (BCC) significantly decreased with advancing GA (correlation coefficient = 0.525-0.823), as confirmed by group comparisons between fetuses in early GA (≤30 weeks) and late GA (>30 weeks) groups. Corticospinal tract, inferior fronto-occipital fasciculus, and GCC showed high reproducibility for fiber count (weighted dice average = 0.846 vs. 0.814), while BCC and ILF exhibited the lowest reproducibility in both age groups. DATA CONCLUSION: The study indicates that the reliability of fetal brain tractography depends on GA and varies among different fibers. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.

Unlocking the link: how hippocampal glutathione-glutamate coupling predicts cognitive impairment in multiple sclerosis patients.

Cognitive impairment is a common symptom of multiple sclerosis and profoundly impacts quality of life. Glutathione (GSH) and glutamate (Glu) are tightly linked in the brain, participating in cognitive function. However, GSH-Glu couplings in cognitive brain regions and their relationship with cognitive impairment in relapsing-remitting multiple sclerosis (RRMS) remains unclear. Forty-one RRMS patients and 43 healthy controls underwent magnetic resonance spectroscopy to measure GSH and Glu levels in the posterior cingulate cortex, medial prefrontal cortex and left hippocampus. Neuropsychological tests were used to evaluate the cognitive function. The Glu/GSH ratio was used to indicate the coupling between GSH and Glu and was tested as a predictor of cognitive performance. The results show that RRMS patients exhibited reduced hippocampal GSH and Glu levels, which were found to be significant predictors of worse verbal and visuospatial memory, respectively. Moreover, GSH levels were dissociated from Glu levels in the left hippocampus of RRMS patients. Hippocampal Glu/GSH ratio is significantly correlated with processing speed and has a greater predictive effect. Here we show the hippocampal Glu/GSH ratio could serve as a new potential marker for characterizing cognitive impairment in RRMS, providing a new direction for clinical detection of cognitive impairment.

sLASER and PRESS perform similarly at revealing metabolite-age correlations at 3 T.

PURPOSE: To compare the respective ability of PRESS and sLASER to reveal biological relationships, using age as a validation covariate at 3 T. METHODS: MRS data were acquired from 102 healthy volunteers using PRESS and sLASER in centrum semiovale and posterior cingulate cortex (PCC). Acquisition parameters included TR/TE = 2000/30 ms, 96 transients, and 2048 datapoints sampled at 2 kHz. Spectra were analyzed using Osprey. SNR, FWHM linewidth of total creatine, and metabolite concentrations were extracted. A linear model was used to compare SNR and linewidth. Paired t-tests were used to assess differences in metabolite measurements between PRESS and sLASER. Correlations were used to evaluate the relationship between PRESS and sLASER metabolite estimates, as well as the strength of each metabolite-age relationship. Coefficients of variation were calculated to assess inter-subject variability in each metabolite measurement. RESULTS: SNR and linewidth were significantly higher (p < 0.01) for sLASER than PRESS in PCC. Paired t-tests showed significant differences between PRESS and sLASER in most metabolite measurements. PRESS-sLASER measurements were significantly correlated (p < 0.05) for most metabolites. Metabolite-age relationships were consistently identified using both methods. Similar coefficients of variation were observed for most metabolites. CONCLUSION: The study results suggest strong agreement between PRESS and sLASER in identifying relationships between brain metabolites and age in centrum semiovale and PCC data acquired at 3 T. sLASER is technically desirable due to the reduced chemical shift displacement artifact; however, PRESS performed similarly in homogeneous brain regions at clinical field strength.

Tescalcin modulates bone marrow-derived mesenchymal stem cells osteogenic differentiation via the Wnt/ß-catenin signaling pathway.

BACKGROUND: Bone mesenchymal stem cells (BMSCs) are recognized for their intrinsic capacity for self-renewal and differentiation into osteoblasts, adipocytes, and chondrocytes, making them pivotal entities within the field of bone research. Tescalcin (TESC) is known to play a role in specific cellular processes related to proliferation and differentiation. However, the precise involvement of TESC in the regulation of BMSCs remains unclear. The present study was designed to verify the functional implications of TESC in BMSCs. METHODS: An adenovirus vector was engineered to downregulate TESC expression, and the Wnt/ß-catenin signaling pathway was activated using BML-284. The assessment of mRNA was conducted by quantitative real-time polymerase chain reaction (qRT-PCR). The assessment of protein expression was conducted by Western blotting and immunofluorescence techniques (IF), respectively. Alkaline phosphatase (ALP) staining and activity assays were performed to verify ALP changes, while Alizarin Red S (ARS) staining and quantitative analysis were employed to assess mineralization capacity. RESULTS: Initially, we observed an upregulation of TESC expression during osteogenic differentiation. Subsequently, TESC knockdown was demonstrated to decrease the osteogenic-related genes expression and diminish BMSCs mineralization. Concomitantly, we identified the inhibition of Wnt/ß-catenin signaling following the TESC knockdown. Furthermore, the administration of BML-284 effectively activated the Wnt/ß-catenin pathway, successfully rescuing the compromised TESC-mediated osteogenic differentiation. CONCLUSION: Our findings indicate that TESC knockdown exerts an inhibitory effect on the osteogenic differentiation of BMSCs through the modulation of the Wnt/ß-catenin signaling pathway. This study unveils a novel target with potential applications for enhancing the regenerative potential of BMSCs in the realm of regenerative medicine.

Three-dimensional magnetic resonance neurography aids in detection of brachial plexus nerve root signal and size alterations in patients with amyotrophic lateral sclerosis: a case-control study.

Background: Since previous histopathological studies have shown a distal to proximal gradient of axonal damage in peripheral nerves of patients with amyotrophic lateral sclerosis (ALS), it would be worthwhile to evaluate consequence of such changes on magnetic resonance imaging (MRI). The aim of this study was to assess proximal-distal longitudinal signal and size alterations of brachial plexus nerve roots in ALS patients using 3-dimensional (3D) magnetic resonance neurography (MRN). Methods: A total of 21 ALS patients and 19 controls were evaluated. The diameters and signal-to-noise (SNR) ratio values of C5-C8 roots were measured at five points from proximal to distal sites. Student's t-test was performed to compare the differences at each point between two groups. Linear regression was performed for each nerve root, and the differences in linear regression slopes between two groups were analyzed. Receiver operating characteristic (ROC) analysis was performed for the diameter and SNR value ratio of the distal to the proximal points. Results: Interobserver agreement was excellent [intraclass correlation coefficient (ICC): 0.802-0.913]. The diameters and SNR values of C5-C8 roots showed a significant decrease (P<0.05) from proximal to distal except SNR value of C5 root in controls. The slope values of diameters in ALS were -0.01924 for C5, -0.04404 for C6, -0.06228 for C7, and -0.06464 for C8. The slope values of SNR values in ALS were -10.14 for C5, -12.86 for C6, -15.99 for C7, and -19.06 for C8. The slope of nerve diameters and SNR values for ALS patients were more negatively sloped than controls (P<0.05) except SNR values of C5 and C7 roots. The ROC analysis confirmed that the diameter and SNR value ratio could differentiate ALS patients from controls with high accuracy. The cutoff values of diameter ratio were 0.7418 for C5, 0.6952 for C6, 0.6431 for C7, and 0.7147 for C8. The cutoff values of SNR value ratio were 0.5989 for C5, 0.6516 for C6, 0.6065 for C7, and 0.6758 for C8. Conclusions: Proximal-distal longitudinal diameters and SNR values decreased significantly for brachial plexus nerve roots in ALS patients with larger differences in slopes compared to controls. These results reflect pathophysiological changes of ALS and may be helpful in improving the diagnosis of ALS.

[Retracted] Expression and function of PIM kinases in osteosarcoma.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that (in addition to overlapping data panels internally within the figure, suggesting that some of the data had been derived from the same original sources where the results of differently performed experiments were intended to have been portrayed) certain of the data featured in Fig. 5A on p. 2123 had already been published in another article written by different authors at different research institutes [Tian F, Ding D and Li D: Fangchinoline targets PI3K and suppresses PI3K/AKT signaling pathway in SGC7901 cells. Int J Oncol 46: 2355­2363, 2015]. Owing to the fact that the contentious data in the above article had already been published prior to its submission to International Journal of Oncology, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Oncology 49: 2116­2126, 2016; DOI: 10.3892/ijo.2016.3708].

Evaluating changes in the strength of the levator ani muscle after vaginal delivery using T2-parameter mapping.

OBJECTIVE: To evaluate pelvic floor muscle injury in patients with levator ani muscle (LAM) weakness after vaginal delivery using T2-parameter mapping. MATERIALS AND METHODS: 40 parturients (patient group) and 25 nonparturients (healthy control group) were enrolled in the study. The LAM weakness group had a Modified Oxford Grading System (MOGS) grade of less than 3 after vaginal delivery. All participants underwent pelvic magnetic resonance imaging (MRI) scans, including T2 and T2* mapping, on which the main branches of the LAM, the puborectalis and iliococcygeus, were evaluated. The differences in T2 and T2* values in the puborectalis and iliococcygeus between patients with LAM weakness and controls were analyzed using an independent samples t test or a Mann-Whitney U test. RESULTS: For both the right and left iliococcygeus, the T2* values of the patient group were lower than those of the control group (P = 0.002 and 0.008, respectively), while no significant difference was observed in the T2 values between the groups (P = 0.45 and 0.69, respectively). For both the right and left puborectalis, no significant differences in the T2* (P = 0.25 and P = 0.25, respectively) or T2 values (P = 0.38 and 0.43, respectively) were observed between the patient and control groups. CONCLUSION: T2* mapping as a quantitative measurement is an effective imaging tool to assess LAM injury in women after vaginal delivery. The iliococcygeus was more susceptible to vaginal delivery damage than the puborectalis, and pelvic floor dysfunction may be mainly driven by iliococcygeus injury.

Romosozumab in osteoporosis: yesterday, today and tomorrow.

Osteoporosis is a systemic bone disease characterized by low bone mass, microarchitectural deterioration, increased bone fragility, and fracture susceptibility. It commonly occurs in older people, especially postmenopausal women. As global ageing increases, osteoporosis has become a global burden. There are a number of medications available for the treatment of osteoporosis, categorized as anabolic and anti-resorptive. Unfortunately, there is no drugs which have dual influence on bone, while all drugs have limitations and adverse events. Some serious adverse events include jaw osteonecrosis and atypical femoral fracture. Recently, a novel medication has appeared that challenges this pattern. Romosozumab is a novel drug monoclonal antibody to sclerostin encoded by the SOST gene. It has been used in Japan since 2019 and has achieved promising results in treating osteoporosis. However, it is also accompanied by some controversy. While it promotes rapid bone growth, it may cause serious adverse events such as cardiovascular diseases. There has been scepticism about the drug since its inception. Therefore, the present review comprehensively covered romosozumab from its inception to its clinical application, from animal studies to human studies, and from safety to cost. We hope to provide a better understanding of romosozumab for its clinical application.

[Retracted] miR­486 suppresses the development of osteosarcoma by regulating PKC­Î´ pathway.

Following the publication of the above article, a concerned reader drew to the Editor's attention that, for the Transwell invasion and migration assay experiments shown in Figs. 5 and 6, there were multiple instances of apparently overlapping data panels, such that the data would have been derived from the same original sources where they were intended to show the results from differently performed experiments; moreover, certain of the data shown in Fig. 5B were strikingly similar to data that had appeared in Fig. 2 in a previously published paper written by different authors at different research institutes [Tian F, Ding D and Li D: Fangchinoline targets PI3K and suppresses PI3K/AKT signaling pathway in SGC7901 cells. Int J Oncol 46: 2355­2363, 2015]. In view of the fact that certain of the data in the above article had already appeared in a previously published paper, and given the large number of apparently overlapping data panels identified in the two referenced figures, the Editor of International Journal of Oncology has decided that this paper should be retracted from the publication. After having been in contact with the authors, they accepted the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Oncology 50: 1590­1600, 2017; DOI: 10.3892/ijo.2017.3928].

Regional changes in brain apparent diffusion coefficient in fetuses with complex congenital heart disease and normal pregnancy assessed using diffusion-weighted imaging.

Objectives: To explore changes in brain apparent diffusion coefficient (ADC) in normal fetuses and fetuses with complex congenital heart disease (CHD) during the second and early third trimesters. Methods: This single-center prospective study was conducted from May 2019 through October 2021. We measured and compared the mean ADC values between 23 fetuses with CHD and 27 gestational age (GA)-matched controls using covariance analyses. ADC density plots and histograms were used to compare brain characteristics. False-discovery rates (FDR, α = 0.05) correction was used for multiple testing. Results: The mean ADC in the frontal white matter, temporal white matter, parietal white matter, occipital white matter, cerebellar hemisphere, central area of the centrum semiovale, basal ganglia region, thalamus, and pons were not significantly different (all p > 0.05). Based on histogram analysis, there were no significant differences between the controls and fetuses with CHD after FDR correction. However, the ADC density plots showed significant heterogeneity between the controls and fetuses with CHD. Conclusion: The mean ADC values and ADC histogram analysis did not differ between the CHD and normal groups. The ADC density plots may provide supplementary information and improve the sensitivity for detecting early brain changes in fetuses with CHD.

Optimization Design of the Bending-Vibration Resistance of Magnetorheological Elastomer Carbon Fibre Reinforced Polymer Sandwich Sheets.

An optimization design of the bending-vibration resistance of magnetorheological elastomer carbon fibre reinforced polymer sandwich sheets (MECFRPSSs) was studied in this paper. Initially, by adopting the classical laminate theory, the Reddy's high-order shear deformation theory, the Rayleigh-Ritz method, etc., an analytical model of the MECFRPSSs was established to predict both bending and vibration parameters, with the three-point bending forces and a pulse load being considered separately. After the validation of the model was completed, the optimization design work of the MECFRPSSs was conducted based on an optimization model developed, in which the thickness, modulus, and density ratios of magnetorheological elastomer core to carbon fibre reinforced polymer were taken as design variables, and static bending stiffness, the averaged damping, and dynamic stiffness parameters were chosen as objective functions. Subsequently, an artificial bee colony algorithm was adopted to execute single-objective, dual-objective, and multi-objective optimizations to obtain the optimal design parameters of such structures, with the convergence effectiveness being examined in a validation example. It was found that it was hard to improve the bending, damping, and dynamic stiffness behaviours of the structure simultaneously as the values of design variables increased. Some compromised results of design parameters need to be determined, which are based on Pareto-optimal solutions. In further engineering application of the MECFRPSSs, it is suggested to use the corresponding design parameters related to a turning point to better exert their bending-vibration resistance.

Altered glutamate-glutamine and amide proton transfer-weighted values in the hippocampus of patients with amnestic mild cognitive impairment: A novel combined imaging diagnostic marker.

Background and purpose: Early diagnosis of amnestic mild cognitive impairment (aMCI) and timely management to delay the onset of Alzheimer's disease (AD) would benefit patients. Pathological metabolic changes of excitatory/inhibitory neurotransmitters and abnormal protein deposition in the hippocampus of aMCI may provide a new clue to imaging diagnosis. However, the diagnostic performance using these hippocampal metabolite measurements is still unclear. We aimed to quantify right hippocampal glutamate-glutamine (Glx) and gamma-aminobutyric acid (GABA) levels as well as protein-based amide proton transfer-weighted (APTw) signals of patients with aMCI and investigate the diagnostic performance of these metabolites. Methods: In this cross-sectional study, 20 patients with aMCI and 20 age- and gender-matched healthy controls (HCs) underwent MEGA Point Resolved Spectroscopy (MEGA-PRESS) and APTw MR imaging at 3 T. GABA+, Glx, and APTw signals were measured in the right hippocampus. The GABA+ levels, Glx levels, Glx/GABA+ ratios, and APTw values were compared between the HCs and aMCI groups using the Mann-Whitney U test. Binary logistic regression and receiver operating characteristic (ROC) curve analyses were used to evaluate MEGA-PRESS and APTw parameters' diagnostic performance. Results: Compared with HCs, patients with aMCI had significantly lower Glx levels in the right hippocampus (7.02 ± 1.41 i.u. vs. 5.81 ± 1.33 i.u., P = 0.018). No significant changes in the GABA+ levels were observed in patients with aMCI (HCs vs. aMCI: 2.54 ± 0.28 i.u. vs. 2.47 ± 0.36 i.u., P = 0.620). In addition, Glx/GABA+ ratios between the two groups (HCs vs. aMCI: 2.79 ± 0.60 vs. 2.37 ± 0.55, P = 0.035) were significantly different. Compared with HCs, patients with aMCI showed higher APTw values in the right hippocampus (0.99 ± 0.26% vs. 1.26% ± 0.28, P = 0.006). The ROC curve analysis showed that Glx, GABA+, Glx/GABA+, and APTw values had an area under the curve (AUC) of 0.72, 0.55, 0.70, and 0.75, respectively, for diagnosing aMCI. In the ROC curve analysis, the AUC of the combination of the parameters increased to 0.88, which is much higher than that observed in the univariate analysis (P < 0.05). Conclusion: The combination of right hippocampal Glx levels and APTw values improved the diagnostic performance for aMCI, indicating it as a promising combined imaging diagnostic marker. Our study provided a potential imaging diagnostic strategy of aMCI, which may promote early detection of aMCI and facilitate timely intervention to delay the pathological progress toward AD.

Differences in left and right carotid plaque vulnerability in patients with bilateral carotid plaques: a CARE-II study.

BACKGROUND AND PURPOSE: Atherosclerosis is a very complex process influenced by various systemic and local factors. Therefore, in patients with bilateral carotid plaques (BCPs), there may be differences in carotid plaque vulnerability between the sides. We aimed to investigate the differences in BCP characteristics in patients with BCPs using magnetic resonance vessel wall imaging (MR-VWI). METHODS: Participants with BCPs were selected for subanalysis from a multicentre study of Chinese Atherosclerosis Risk Evaluation II. We measured carotid plaque burden, identified each plaque component and measured their volume or area bilaterally on MR-VWI. Paired comparisons of the burden and components of BCPs were performed. RESULTS: In all, 540 patients with BCPs were eligible for analysis. Compared with the right carotid artery (CA), larger mean lumen area (p<0.001), larger mean wall area (p=0.025), larger mean total vessel area (p<0.001) and smaller normalised wall index (p=0.006) were found in the left CA. Regarding plaque components, only the prevalence of lipid-rich necrotic core (LRNC) in the left CA was higher (p=0.026). For patients with a vulnerable plaque component coexisting on both sides, only the intraplaque haemorrhage (IPH) volume (p=0.011) was significantly greater in the left CA than in the right CA. CONCLUSIONS: There were asymmetries in plaque growth and evolution between BCPs. The left carotid plaques were more likely to have larger plaque burden, higher prevalence of LRNC and greater IPH volume, which may contribute to the lateralisation of ischaemic stroke in the cerebral hemispheres.