Design of SiOx/TiO2@C hierarchical structure for efficient lithium storage.

The large volume expansion effect and unstable solid electrolyte interface films of SiOx-based anode materials have hindered their commercial development. It has been shown that composite doping is a general strategy to solve critical problems. In this study, TiO2-doped core-shell SiOx/TiO2@C composites were created using the sol-gel method. On the one hand, the uniformly dispersed TiO2nanoparticles can alleviate the volume expansion of the SiOxactive material during the lithiation process. On the other hand, they can react with Li+to form LixTiO2, thereby increasing the ion diffusion rate in the composite material. The outer carbon shell acts as a protective layer that not only alleviates the volume expansion of the composite, but also improve the electron migration rate of the composite. The prepared SiOx/TiO2@C composite has a reversible capacity of 828.2 mA h g-1(0.2 A g-1100 cycles). After 500 cycles, it still maintains a reversible capacity of 500 mA h g-1even at a high current density of 2 A g-1. These findings suggest that SiOx/TiO2@C composites have a bright future in applications.

Rapid Prediction and Accurate Location Selection of Mild Traumatic Brain Injury (mTBI) by Using Multiple Parameter Analysis of Diffusion Tensor Imaging (DTI): Integrating Correlational and Clinical Approaches.

Background: Mild traumatic brain injury (mTBI) is a widespread and serious public health problem which also causes physical and psychological suffering to patients and their families and imposes a significant economic burden on society. But it is usually very difficult to detect and provide warning of mTBI in early stage. Therefore, a novel method is urgent for the increasing demands on the accurate and rapid prediction and feature selection of mTBI. Objectives: To establish a better idea of the performance of neuroimage biomarker in the acute phase of mTBI, our study adopts diffusion tensor imaging (DTI) which could present the pathophysiological changes of white matter through several parameters noninvasively and combined with behavioral experiments such as intelligence quotient test, memory, executive function, and motion function to find the relationship between DTI abnormal brain regions and behavioral abnormalities. Then, provide new method for rapid prediction and feature selection of mTBI. Methods: 77 mTBI patients were admitted to the Emergency and Neurosurgery Departments of the Third Xiangya Hospital of Central South University from August 2019 to July 2021; the patients (41 males and 36 females) suffered mTBI because of car accident (36), assault (11), and fall (30). All the mTBI patients were examined through MRI scan and behavioral psychology test within 3 days after injury. MRI images and behavioral psychology tests were also collected; the correlation between the DTI biomarker and the cognitive psychological outcome was analyzed. A series of integration and computational methods were also used for fusion arithmetic and result analysis. Results: Compared with the healthy control group, the patients in the acute stage of mTBI presented lower scores in the digit symbol substitution test (DSST), suggesting that mTBI patients in the acute stage had decline in information processing speed and associative learning. The difference of DTI parameters in acute stage mTBI patients was mainly manifested as increased AD and MD values in multiple brain regions, while RD and FA values have no significant difference. The most significant brain regions were bilateral corticospinal tracts (CST), bilateral posterior internal capsule lentiform nucleus, bilateral superior longitudinal fasciculus, left terminal striae, and left sagittal plane with right posterior thalamic radiation. The Pearson correlation coefficient was significantly positive correlation between AD and MD elevation in the left sagittal layer and the results of DSST and digit span in acute stage mTBI patients. Conclusions: The acute phase mTBI patients performed lower score on the DSST than those in the normal control group. This neuropsychological change was associated with increased AD value and MD value in the left sagittal layer, which indicated reduction of information processing speed in mTBI patients in the acute phase. It might be related to abnormal AD value and MD value in the upper longitudinal tract, lower longitudinal tract, lower frontal occipital tract, and sagittal layer. In this study, combined with neuropsychological test and increase of the AD value and MD value in certain brain region, neurosurgeon should pay more attention to the abnormal of the upper longitudinal tract and the patients' information processing speed in the diagnosis and treatment of the acute phase mTBI patients. The study offers a much more secure and integrated method for rapid prediction and feature selection of mTBI, which could have broader clinical approaches and application prospects.

Biomechanical influence of T1 tilt alteration on adjacent segments after anterior cervical fusion.

Background: Anterior cervical fusion (ACF) has become a standard treatment approach to effectively alleviate symptoms in patients with cervical spondylotic myelopathy and radiculopathy. However, alteration of cervical sagittal alignment may accelerate degeneration at segments adjacent to the fusion and thereby compromise the surgical outcome. It remains unknown whether changes in T1 tilt, an important parameter of cervical sagittal alignment, may cause redistribution of biomechanical loading on adjacent segments after ACF surgery. Objective: The objective was to examine the effects of T1 tilt angles on biomechanical responses (i.e.range of motion (ROM) and intradiscal VonMises stress) of the cervical spine before and after ACF. Methods: C2-T1 FE models for pre- and postoperative C4-C6 fusion were constructed on the basis of our previous work. Varying T1 tilts of -10°, -5°, 0°, 5°, and 10° were modeled with an imposed flexion-extension rotation at the T1 inferior endplate for the C2-T1 models. The flexion-extension ROM and intradiscal VonMises stress of functional spinal units were compared between the pre- and postoperative C2-T1 FE models of different T1 tilts. Results: The spinal segments adjacent to ACF demonstrated higher ROM ratios after the operation regardless of T1 tilt. The segmental ROM ratio distribution was influenced as T1 tilt varied and loading conditions, which were more obvious during displacement-control loading of extension. Regardless of T1 tilt, intradiscal VonMises stress was greatly increased at the adjacent segments after the operation. As T1 tilt increased, intradiscal stress at C3-C4 decreased under 30° flexion and increased under 15° extension. The contrary trend was observed at the C6-C7 segment, where the intradiscal stress increased with the increasing T1 tilt under 30° flexion and decreased under 15° extension. Conclusion: T1 tilt change may change biomechanical loadings of cervical spine segments, especially of the adjacent segments after ACF. Extension may be more susceptible to T1 tilt change.

Effect of cervical alignment change after anterior cervical fusion on radiological adjacent segment pathology.

Background: Adjacent segment pathology (ASP) is one of the primary complications affecting the long-term efficacy of anterior cervical fusion (ACF). At present, the cause and mechanism of adjacent segmental lesions are still controversial. Methods: We performed a retrospective analysis on 88 patients with cervical spondylotic myelopathy (CSM) who had been followed up for at least 1 year after ACF. The patients were divided into radiological adjacent segment pathology (RASP) and non-RASP groups according to the presence of postoperative RASP. On the lateral radiographs of the cervical spine of all patients taken before and after surgery at the short-term and final follow-ups, the following parameters were measured: C2-7 Cobb angle of the cervical vertebrae; Cobb angle of the operated segments; and the anterior and posterior height of the fused segments [i.e., the anterior fusion segment height (AFH) and the posterior fusion segment height (PFH)]. The intra- and inter-group differences of the patients before and after surgery were calculated, as well as correlation of ACF with the occurrence of RASP. Results: There were 42 cases in the RASP group and 46 cases in the non-RASP group. In the RASP group, the C2-7 Cobb angle was significantly reduced in the short term after surgery (20.42±9.92° vs. 13.81±8.52°, P<0.01), while in non-RASP group the C2-7 Cobb angle was significantly increased in the short term after surgery (12.65±11.91° vs. 15.35±10.05°, P<0.05). The heights of both the anterior and posterior fused segments in the 2 groups were significantly higher after surgery, and they were significantly lower at the final follow-up than at the short-term follow-up. Post-operative AFH change was significantly correlated with C2-7 Cobb angle (r=0.274, P=0.010) and fused segment Cobb angle change (r=0.333, P=0.002). However, Cox regression analysis showed that only the postoperative C2-7 Cobb angle change was associated with RASP, with a hazard ratio of 0.336. Conclusions: Decreased cervical lordosis after ACF may be related to postoperative RASP. Maintaining good cervical curvature after surgery may reduce the incidence of RASP after ACF.

The Multi-Modal Risk Analysis and Medical Prevention of Lumbar Degeneration, Fatigue, and Injury Based on FEM/BMD for Elderly Chinese Women Who Act as Stay-Home Grandchildren Sitters.

Background: An increasing number of Chinese elderly women stay at home and act as grandchildren sitters. In consequence of the frequent load-bearing, chronic lumbar fatigue probably caused a higher risk of lumbar degeneration, fatigue, and injury which has become one of the most important aging and health problems in China. In this study, a multi-mode lumbar finite element model (FEM) with specific bone mineral density (BMD) were developed and validated for further spine injury prevention and control. Methods: The material properties of lumbar vertebra were modified according to degenerated bone mineral density, and geometry was adjusted based on intervertebral disc height. The motion of lifting children was simulated by a 76 year-old Chinese women's FEM, and the stress distribution was calculated and predicted. Results: The pressure of L5-S intervertebral disc in the bending 3-year-old dummy lifting posture was significantly higher than the same posture without lifting, the maximum effective stress of endplate cartilage in the upright child lifting posture was 1.6 times that of the bending without lifting posture. And the fatigue risk limitation frequency of the upright with dummy posture was predicted with the functional equation of fatigue and stress which was deduced by genetic algorithm, which combined with the effective stress of lumbar vertebrae spongy bone calculated from FEM. Conclusions: The child-lifting motion could increase the risk of lumbar degeneration, fatigue, and injury in elderly women, and they should keep below the frequency limit of the motion of lifting children in their daily life. This study could put forward scientific injury prevention guidance to Chinese elderly women who lift children in daily life frequently.

A Bibliometric Analysis and Visualization of the Top-Cited Publications in Mild Traumatic Brain Injury.

Background: For measuring their impact in scientific research, the citation count of the publications is used in the bibliometric analysis, though still in the bibliometric analysis, there is no comprehensive summary of mild traumatic brain injury (mTBI) research. This article intends to provide the physicians and the neuroscientists with a reference guide to assess the most influential publications written on this subject through a macroscopic view of the research activities on mTBI. Methods: The database of the Web of Science was used to compile the 100 top-ranking publications on mTBI. The selected publications were evaluated on the basis of the several categorizations including the type of the publications, number of citations, country of origin, and year of publication. Results: Between 1946 and 2020, the 13,040 publications that were published were included in the database. The least cited publications received 274 citations, while the most cited received 1,748. Altogether, 71 publications were from the USA while 29 were from other countries. Among all the institutions, the University of Pittsburgh Medical Center led the list with six publications. Around 100 papers, mostly on the clinical studies in the categories of neurology and neurosciences, were published in 54 different journals. Conclusions: This study provides both a transverse section summary and historical retrospect for the clinical advances of mTBI, and the publications of important observations that contributed a significant impact on the treatment and prevention of mTBI had been identified.

Multi-Modal Analysis of Resting-State fMRI Data in mTBI Patients and Association With Neuropsychological Outcomes.

Various cognitive disorders have been reported for mild traumatic brain injury (mTBI) patients during the acute stage. This acute stage provides an opportunity for clinicians to optimize treatment protocols, which are based on the evaluation of brain structural connectivity. So far, most brain functional magnetic resonance imaging studies are focused on moderate to severe traumatic brain injuries (TBIs). In this study, we prospectively collected resting state data on 50 mTBI within 3 days of injury and 50 healthy volunteers and analyzed them using Amplitude of low-frequency fluctuation (ALFF), Regional Homogeneity (ReHo), graph theory methods and behavior measure, to explore the dysfunctional brain regions in acute mTBI. In our study, a total of 50 patients suffering <3 days mTBI and 50 healthy subjects were tested in rs-fMRI, as well as under neuropsychological examinations including the Wechsler Intelligence Scale and Stroop Color and Word Test. The correlation analysis was conducted between graph theoretic parameters and neuropsychological results. For the mTBI group, the ReHo of the inferior temporal gyrus and the cerebellum superior are significantly lower than in the control group, and the ALFF of the left insula, the cerebellum inferior, and the middle occipital gyrus were significantly higher than in the control group, which implies the dysfunctionality usually observed in Parkinson's disease. Executive function disorder was significantly correlated with the global efficiencies of the dorsolateral superior frontal gyrus and the anterior cingulate cortex, which is consistent with the literature: the acute mTBI patients demonstrate abnormality in terms of motor speed, association, information processing speed, attention, and short-term memory function. Correlation analysis between the neuropsychological outcomes and the network efficiency for the mTBI group indicates that executive dysfunction might be caused by local brain changes. Our data support the idea that the cerebral internal network has compensatory reactions in response to sudden pathological and neurophysiological changes. In the future, multimode rs-fMRI analysis could be a valuable tool for evaluating dysfunctional brain regions after mTBI.

Study on the Long Bone Failure Behaviors Under the Indenter Rigid-Contact by Experiment Analysis and Subject-Specific Simulation.

The bending fracture behaviors of long bone have gained great attention due to the high bending fracture risk during sports events, traffic accidents, and falling incidents, etc. For evaluating bone bending behaviors, most of the previous studies used an indenter in three point bending experiments while the effect of its rigidity was never considered. In this work, using the porcine long bones, the three point bending tests were conducted to explore the bone fracture behaviors under a rigid indenter. In addition to collecting the force applied, the bone fracture dynamic process was recorded by high-speed photography, and the fracture surface profile in mesoscale was observed by the scanning electron microscope (SEM). Based on CT scanning of long bones, the cross section properties of test specimens were calculated by a homemade matlab script for correlating with their failure strengths. Also, a subject-specific finite element (FE) model was developed to identify the outcomes induced by a rigid indenter on simulation. Findings led to conclusions as follows: (1) The tension fracture came with fracture path deflection, which was caused by the bone indentation induced mesoscale crack-opening. Due to this damage before the whole bone fracture, a bone fracture moment correction was established to compensate experimental data. (2) The plastic indentation caused the force fluctuation as suggested by correlation analysis. (3) The bone failure moment correlated with the inertial moment of the bone cross section at the fracture location higher than the traditional cross section area. (4) In the subject-specific simulation, the indentation caused compression fracture under a much lower failure force. Removing the element erosion on the indenter-contacted area only during the validation was verified as a good option to solve this issue.

Optimizing bone cement stiffness for vertebroplasty through biomechanical effects analysis based on patient-specific three-dimensional finite element modeling.

Vertebroplasty is a common and effective treatment for symptomatic osteoporotic vertebral compression fractures. However, the cemented and adjacent vertebras have a risk of recollapse due to largely unassured mechanisms, among which excessive stiffness of bone cement may be an important risk factor. This study aimed to find the most appropriate range of bone cement stiffness by analyzing its biomechanical effects on the augmented and adjacent vertebras of individual patient after vertebroplasty. A three-dimensional finite element model of T11-L1 osteoligamentous vertebras was reconstructed according to individual computed tomography data and validated by post mortem human subject experiment in literatures. Bone cement of varying stiffness was injected into the trabecular core of the T12 vertebra simulatively. The maximum von Mises stresses on cancellous and cortical bones of T11-L1 vertebras were analyzed under the loading conditions of flexion, extension, bending, and torsion. For the adjacent T11 and L1 vertebras, the stepwise elevation of the bone cement elastic modulus increased the maximum von Mises stress on the cancellous bone, but its effect on cortical bone was negligible. For the augmented T12 vertebra, the stresses on cancellous bone increased slightly under the loading condition of lateral bending and remained no impact on cortical bone. The linear interpolation revealed that the most suitable range of cement elastic modulus is 833.1 and 1408.1 Mpa for this patient. Increased elastic modulus of bone cement may lead to a growing risk of recollapse for the cemented vertebra as well as the adjacent vertebras. Our study provides a fresh perspective in clinical optimization of individual therapy in vertebroplasty. Graphical abstract ᅟ.

A Lower Limb-Pelvis Finite Element Model with 3D Active Muscles.

A lower limb-pelvis finite element (FE) model with active three-dimensional (3D) muscles was developed in this study for biomechanical analysis of human body. The model geometry was mainly reconstructed from a male volunteer close to the anthropometry of a 50th percentile Chinese male. Tissue materials and structural features were established based on the literature and new implemented experimental tests. In particular, the muscle was modeled with a combination of truss and hexahedral elements to define its passive and active properties as well as to follow the detailed anatomy structure. Both passive and active properties of the model were validated against the experiments of Post-Mortem Human Surrogate (PMHS) and volunteers, respectively. The model was then used to simulate driver's emergency braking during frontal crashes and investigate Knee-Thigh-Hip (KTH) injury mechanisms and tolerances of the human body. A significant force and bending moment variance was noted for the driver's femur due to the effects of active muscle forces during emergency braking. In summary, the present lower limb-pelvis model can be applied in various research fields to support expensive and complex physical tests or corresponding device design.