热塑性淀粉的制备及在聚乳酸复合材料中的应用

通过糠基缩水甘油醚(FGE)的化学接枝改性,成功制得具有优异熔融加工性能的热塑性淀粉。红外光谱和核磁共振氢谱分析表明,通过马来酸酐的桥接作用,FGE成功接枝到淀粉分子上。X射线衍射分析发现,FGE的接枝能有效破坏淀粉的晶体结构,从而赋予FGE接枝淀粉(FGE-g-St)优异的热塑性加工性能。动态接触角测试发现,FGE-g-St的接触角从原淀粉(N-St)的30°左右提高至65°左右,表现出极其优异的疏水性能,从而显著改善了FGE-g-St与聚乳酸的界面相容性。相对于PLA/N-St复合材料,PLA/FGE-g-St复合材料的拉伸强度、弯曲强度和断裂伸长率均得到显著提高,这得益于其优异的界面相容性。

Brain structure in post-traumatic stress disorder A voxel-based morphometry analysis

This study compared the difference in brain structure in 12 mine disaster survivors with chronic post-traumatic stress disorder, 7 cases of improved post-traumatic stress disorder symptoms, and 14 controls who experienced the same mine disaster but did not suffer post-traumatic stress disorder, using the voxel-based morphometry method. The correlation between differences in brain structure and post-traumatic stress disorder symptoms was also investigated. Results showed that the gray matter volume was the highest in the trauma control group, followed by the symptoms-improved group, and the lowest in the chronic post-traumatic stress disorder group. Compared with the symptoms-improved group, the gray matter volume in the lingual gyrus of the right occipital lobe was reduced in the chronic post-traumatic stress disorder group. Compared with the trauma control group, the gray matter volume in the right middle occipital gyrus and left middle frontal gyrus was reduced in the symptoms-improved group. Compared with the trauma control group, the gray matter volume in the left superior parietal lo- bule and right superior frontal gyrus was reduced in the chronic post-traumatic stress disorder group. The gray matter volume in the left superior parietal Iobule was significantly positively correlated with the State-Trait Anxiety Inventory subscale score in the symptoms-improved group and chronic post-traumatic stress disorder group （r = 0.477, P = 0.039）. Our findings indicate that （1） chronic post-traumatic stress disorder patients have gray matter structural damage in the prefrontal lobe, oc- cipital lobe, and parietal lobe, （2） after post-traumatic stress, the disorder symptoms are improved and gray matter structural damage is reduced, but cannot recover to the trauma-control level, and （3） the superior parietal Iobule is possibly associated with chronic post-traumatic stress disorder. Post-traumatic stress disorder patients exhibit gray matter abnormalities.

Microstructural changes in memory and reticular formation neural pathway after simple concussion

Patients with concussion often present with temporary disturbance of consciousness. The microstructural and functional changes in the brain associated with concussion, as well as the relationship with transient cognitive disorders, are currently unclear. In the present study, a rabbit model of simple concussion was established. Magnetic resonance-diffusion tensor imaging results revealed that the corona radiata and midbrain exhibited significantly decreased fractional anisotropy values in the neural pathways associated with memory and the reticular formation. In addition, the apparent diffusion coefficient values were significantly increased following injury compared with those before injury. Following a 1-hour period of quiet rest, the fractional anisotropy values significantly increased, and apparent diffusion coefficient values significantly decreased, returning to normal pre-injury levels. In contrast, the fractional anisotropy values and apparent diffusion coefficient values in the corpus callosum, thalamus and hippocampus showed no statistical significant alterations following injury. These findings indicate that the neural pathways associated with memory and the reticular formation pathway exhibit reversible microstructural white matter changes when concussion occurs, and these changes are exhibited to a different extent in different regions.

Soft Mesoporous Organosilica Nanoplatforms Improve Blood Circulation,Tumor Accumulation/Penetration,and Photodynamic Efficacy

To date,the ability of nanoplatforms to achieve excellent therapeutic responses is hindered by short blood circulation and limited tumor accumulation/penetration.Herein,a soft mesoporous organosilica nanoplatform modified with hyaluronic acid and cyanine 5.5 are prepared,denoted SMONs-HA-Cy5.5,and comparative studies between SMONs-HA-Cy5.5(24.2 MPa)and stiff counterparts(79.2 MPa)are conducted.Results indicate that,apart from exhibiting a twofold increase in tumor cellular uptake,the soft nanoplatforms also display a remarkable pharmacokinetic advantage,resulting in considerably improved tumor accumulation.Moreover,SMONs-HA-Cy5.5 exhibits a significantly higher tumor penetration,achieving 30-μm deeper tissue permeability in multicellular spheroids relative to the stiff counterparts.Results further reveal that the soft nanoplatforms have an easier extravasation from the tumor vessels,diffuse farther in the dense extracellular matrix,and reach deeper tumor tissues compared to the stiff ones.Specifically,the soft nanoplatforms generate a 16-fold improvement(43 vs.2.72μm)in diffusion distance in tumor parenchyma.Based on the significantly improved blood circulation and tumor accumulation/penetration,a soft therapeutic nanoplatform is constructed by loading photosensitizer chlorin e6 in SMONs-HA-Cy5.5.The resulting nanoplatform exhibits considerably higher therapeutic efficacy on tumors compared to the stiff ones.

Mechanism of Neurophysiological Treatment of Amblyopia Using Functional Magnetic Resonance Imaging

Purpose: To research the mechanism of neurophysiological treatment of amblyopia by observing the visual cortex activation under rotating grating stimulus with functional magnetic resonance imaging (MRI), and identify the components of the activation. Methods: Nine healthy volunteers were examined using gradient-recalled echo and echo-planar imaging (GRE-EPI) pulse sequence performed at the 1.5 Tesla MRI scanner. In the block designing, rotating grating, stationary grating and luminance were plotted as task states, stationary grating, luminance and darkness as control states, respectively. The tasks of stimuli included 6 steps. Imaging processing and statistical analysis were carried out off-line using statistical parametric mapping (SPM99) software in single-subject. Results: Some individual areas of visual cortex were activated by various stimuli information supplied by rotating grating. The strong activation in the middle of occipital lobe related to the stimuli of luminance, bilateral activation of Brodmann’s 19th area related to visual motion perception, and the mild activation in the middle of occipital lobe related to form perception. Conclusion: The plotting of control state is important in bock design. The effective visual information of rotating grating includes components of luminance, visual motion perception and form perception. Functional MRI has potential as a tool for studying the physiological mechanism of visual cortex.

基于人工智能的全自动化一站式CT血流储备分数在冠心病 患者中的诊断与预后价值

Currently,clinically available coronary CT angiography(CCTA)derived fractional flow reserve(CT-FFR)is time-consuming and complex.We propose a novel artificial intelligence-based fully-automated,on-site CT-FFR technology,which combines the automated coronary plaque segmentation and luminal extraction model with reduced order 3 dimentional(3D)computational fluid dynamics.A total of 463 consecutive patients with 600 vessels from the updated China CT-FFR study in Cohort 1 undergoing both CCTA and invasive fractional flow reserve(FFR)within 90 d were collected for diagnostic performance evaluation.For Cohort 2,a total of 901 chronic coronary syndromes patients with index CT-FFR and clinical outcomes at 3-year follow-up were retrospectively analyzed.In Cohort 3,the association between index CT-FFR from triple-rule-out CTA and major adverse cardiac events in patients with acute chest pain from the emergency department was further evaluated.The diagnostic accuracy of this CT-FFR in Cohort 1 was 0.82 with an area under the curve of 0.82 on a per-patient level.Compared with the manually dependent CT-FFR techniques,the operation time of this technique was substantially shortened by 3 times and the number of clicks from about 60 to 1.This CT-FFR technique has a highly successful(>99%)calculation rate and also provides superior prediction value for major adverse cardiac events than CCTA alone both in patients with chronic coronary syndromes and acute chest pain.Thus,the novel artificial intelligencebased fully automated,on-site CT-FFR technique can function as an objective and convenient tool for coronary stenosis functional evaluation in the real-world clinical setting.

Aberrant Resting-State Functional Connectivity in the Default Mode Network in Pediatric Bipolar Disorder Patients with and without Psychotic Symptoms

Mood disorders/psychosis have been associated with dysfunctions in the default mode network(DMN).However,the relative contributions of DMN regions to state and trait disturbances in pediatric bipolar disorder(PBD)remain unclear.The aim of this study was to investigate the possible mechanisms of PBD through brain imaging and explore the influence of psychotic symptoms on functional alterations in PBD patients.Twenty-nine psychotic and 26 non-psychotic PBD patients,as well as 19 age-and sex-matched healthy controls underwent a restingstate functional MRI scan and the data were analyzed by independent component analysis.The DMN component from the fMRI data was extracted for each participant.Spearman's rank correlation analysis was performed between aberrant connectivity and clinical measurements.The results demonstrated that psychotic PBD was characterized by aberrant DMN connectivity in the anterior cingulate cortex/medial prefrontal cortex,bilateral caudate nucleus,bilateral angular gyri,and left middle temporal gyrus,while non-psychotic PBD was not,suggesting further impairment with the development of psychosis.In summary,we demonstrated unique impairment in DMN functional connectivity in the psychotic PBD group.These specific neuroanatomical abnormalities may shed light on the underlying pathophysiology and presentation of PBD.

Altered relationship between thickness and intrinsic activity amplitude in generalized tonic–clonic seizures

A thinner cortex has higher potential for binding GABA receptor A which is associated with larger amplitudes of intrinsic brain activity(i BA). However, the relationship between cortical thickness and i BA is unknown in intact and epileptic brains. To this end, we investigated the relationship between cortical thickness measured by highresolution MRI and surface-based i BA derived from resting-state functional MRI in normal controls(n = 82) andpatients with generalized tonic–clonic seizures(GTCS)only(n = 82). We demonstrated that the spatial distribution of cortical thickness negatively correlated with surface-based i BA amplitude at both whole-brain and within independent brain functional networks. In GTCS patients,spatial coupling between thickness and i BA amplitude decreased in the default mode, dorsal attention, and somatomotor networks. In addition, the vertex-wise acrosssubject thickness–i BA amplitude correspondence altered in the frontal and temporal lobes as well as in the precuneus in GTCS patients. The relationship between these two modalities can serve as a brain-based marker for detecting epileptogenic changes.

Effect of lamellar structural parameters on the bending fracture behavior of AA1100/AA7075 laminated metal composites

The lamellar structure has an important impact on the mechanical properties of dissimilar laminated metal composites(LMCs),including the thickness ratio of dissimilar metal constituent layers and the number of layers.AA1100 and AA7075 with thickness ratios of 1:4 and 3:4 were fabricated for multilayer AA1100/AA7075 LMCs by hot accumulative roll bonding(ARB)technology.The bending fracture characteristics of AA1100/AA7075 LMCs with different thickness ratios and numbers of constituent layers were investigated.The research results indicated that AA1100/AA7075 LMCs with a low thickness ratio exhibited better bending ductility and toughness than those with a high thickness ratio,which was attributed to the crack growth resistance caused by the thickness of the soft AA1100 layer.The toughening mechanism introduced by crack deflection or arresting contributed to the enhancement in the toughness of the LMCs compared with that of the single 7075 Al layer.The bonding interfaces of AA1100/AA7075 LMCs with different numbers of layers are continuous and straight due to the high ARB temperature.A decrease in bending toughness was observed as the number of layers increased.Unlike LMCs with a low number of layers,crack deflection or interface delamination is also considered a main toughening mechanism in dissimilar LMCs in addition to the thickness effect.

Computed tomography and photoacoustic imaging guided photodynamic therapy against breast cancer based on mesoporous platinum with insitu oxygen generation ability

Photodynamic therapy(PDT)has been widely used in cancer treatment.However,hypoxia in most solid tumors seriously restricts the efficacy of PDT.To improve the hypoxic microenvironment,we designed a novel mesoporous platinum(mPt)nanoplatform to catalyze hydrogen peroxide(H2 O2)within the tumor cells in situ without an extra enzyme.During the fabrication,the carboxy terminus of the photosensitizer chlorin e6(Ce6)was connected to the amino terminus of the bifunctional mercaptoaminopolyglycol(SH-PEG-NH2)by a condensation reaction,and then PEG-Ce6 was modified onto the mPt moiety via the mercapto terminal of SH-PEG-NH2.Material,cellular and animal experiments demonstrated that Pt@PEG-Ce6 catalyzed H2 O2 to produce oxygen(O2)and that Ce6 transformed O2 to generate reactive oxygen species(ROS)upon laser irradiation.The Pt@PEG-Ce6 nanoplatform with uniform diameter presented good biocompatibility and efficient tumor accumulation.Due to the high atomic number and good near-infrared absorption for Pt,this Pt@PEG-Ce6 nanoplatform showed computed tomography(CT)and photoacoustic(PA)dual-mode imaging ability,thus providing an important tool for monitoring the tumor hypoxic microenvironment.Moreover,the Pt@PEG-Ce6 nanoplatform reduced the expression of hypoxia-inducible factor-la(HIF-1α)and programmed death-1(PD-1)in tumors,discussing the relationship between hypoxia,PD-1,and PDT for the first time.

Deformable double-shelled hollow mesoporous organosilica nanocapsules:A multi-interfacial etching strategy

Multishelled hollow structures have drawn increasing interest because of their peculiar compartmentation environments and physicochemical properties.In this work,deformable double-shelled hollow mesoporous o rganosilica nanocapsules(DDHMONs)were succes s fully synthesized by a multi-interfacial etching strategy.The obtained DDHMONs have a double-shelled structure with aninorganic-organic hybrid framework,a uniform outer layer(~320 nm)and inner layer(~180 nm),ordered mesochannels(~2.21 nm),and a large specific surface area(~1233 m^(2)/g).In vitro toxicity tests show that the DDHMONs have excellent biocompatibility when coincubated with human breast cancer cells.In addition,the anti cancer substance doxorubicin(DOX)can be highly loaded in DDHMONs(~335μg/mg).The results from flow cytometry together with confocal laser scanning microscopy show that DOX can be efficiently delivered into MCF-7 cells by DDHMONs,thus improving chemotherapeutic efficiency and demonstrating that DDHMONs have potential nanomedicine applications as anticancer agents.

Current vortices and magnetic fields driven by moving polar twin boundaries in ferroelastic materials

Ferroelastic twin boundaries often have properties that do not exist in bulk,such as superconductivity,polarity etc.Designing and optimizing domain walls can hence functionalize ferroelastic materials.Using atomistic simulations,we report that moving domain walls have magnetic properties even when there is no magnetic element in the material.The origin of a robust magnetic signal lies in polar vortex structures induced by moving domain walls,e.g.,near the tips of needle domains and near domain wall kinks.These vortices generate displacement currents,which are the origin of magnetic moments perpendicular to the vortex plane.This phenomenon is universal for ionic crystals and holds for all ferroelastic domain boundaries containing dipolar moments.

Study design of deep learning based automatic detection of cerebrovascular diseases on medical imaging: a position paper from Chinese Association of Radiologists

In recent years,with the development of artificial intelligence,especially deep learning technology,researches on automatic detection of cerebrovascular diseases on medical images have made tremendous progress and these models are gradually entering into clinical practice.However,because of the complexity and flexibility of the deep learning algorithms,these researches have great variability on model building,validation process,performance description and results interpretation.The lack of a reliable,consistent,standardized design protocol has,to a certain extent,affected the progress of clinical translation and technology development of computer aided detection systems.After reviewing a large number of literatures and extensive discussion with domestic experts,this position paper put forward recommendations of standardized design on the key steps of deep learning-based automatic image detection models for cerebrovascular diseases.With further research and application expansion,this position paper would continue to be updated and gradually extended to evaluate the generalizability and clinical application efficacy of such tools.

Cell-type-specific genes associated with cortical structural abnormalities in pediatric bipolar disorder

Background Pediatric bipolar disorder(PBD)has been proven to be related to abnormal brain structural connectivity,but how the abnormalities in PBD correlate with gene expression is debated.Objective This study aims at identification of cell-type-specific gene modules based on cortical structural differences in PBD.Methods Morphometric similarity networks(MSN)were computed as a marker of interareal cortical connectivity based on MRI data from 102 participants(59 patients and 43 controls).Partial least squares(PLS)regression was used to calculate MSN differences related to transcriptomic data in AHBA.The biological processes and cortical cell types associated with this gene expression profile were determined by gene enrichment tools.Results MSN analysis results demonstrated differences of cortical structure between individuals diagnosed with PBD and healthy control participants.MSN differences were spatially correlated with the PBD-related weighted genes.The weighted genes were enriched for“trans-synaptic signaling”and“regulation of ion transport”,and showed significant specific expression in excitatory and inhibitory neurons.Conclusions This study identified the genes that contributed to structural network aberrations in PBD.It was found that transcriptional changes of excitatory and inhibitory neurons might be associated with abnormal brain structural connectivity in PBD.