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The effect of amide functional groups at the nanodiamond surface is of great significance. Herein, we develop a new facile, inexpensive, and contaminant-free approach to modify nanodiamond surface through the mechanochemical amidation of nanodiamond using ball milling technique in the presence of ammonium chloride (NH4Cl) as amidation reagent to introduce the amide functional groups on the nanodiamond surface. It is observed that the amidated nanodiamonds can uniformly disperse well in an aqueous solution. Moreover, the results indicated that the technique is easy to operate and scale-up for industrial application. Furthermore, the well-dispersed nanodiamond colloids can be used for numerous applications including lubrication, thermal interface materials, and drug delivery system. More interesting, the dried amidated nanodiamond can be re-dispersed back to the colloidal solution of a wide range of solvents including water, dimethylsulfoxide, dimethyl formamide and ethanol, which greatly expands the application and functionality of nanodiamond.

The nanodiamond (ND) particles have several potential applications including tribology, drug delivery, bioimaging, etc. However, the severe colloidal aggregation tendency of ND particles strictly limits its exploitation. Moreover, due to NDs rich surface chemistry and relatively small size, it is still difficult to separate these large ND particles using conventional separation methods. Herein, we develop an efficient and straightforward strategy to separate the colloidal aminated nanodiamonds (ND-NH2) into small size nanoparticles by viscosity gradient centrifugation method in a polyvinylpyrrolidone (PVP) aqueous solution. Prior to and after separation, the pristine ND and ND-NH2 particles size and morphology were characterized by DLS (dynamic light scattering analyzer) and TEM (transmission electron microscopic), which show that ND particles with narrow size distribution and uniform morphology can be easily separated by the viscosity gradient of PVP aqueous solution. This simple, rapid and effective separation method could be extended to separate other functionalized NDs with different sizes.

Sepsis-associated encephalopathy (SAE) is key manifestation of sepsis which is responsible for increased morbidity and mortality. Leucine rich alpha-2-glycoprotein 1 (Lrg1) is a secreted protein implicated in a variety of diseases. We aimed to explore the effects and potential mechanism of Lrg1 on sepsis-mediated brain injury. A sepsis-induced brain damage mice model was established. Then, ELISA was utilized to detect the levels of inflammatory factors in brain tissues. Behavioral performance, spatial learning and memory of mice were evaluated by open field test and Morris water maze test. The number of neurons was tested by HE staining. Lrg1 expression was evaluated by RT-qPCR and western blot. In vitro, mouse hippocampal neuronal cell line (HT22) was stimulated by lipopolysaccharide (LPS). After Lrg1 silencing, cell viability was determined using CCK-8 and cell apoptosis was assessed by TUNEL. The levels of inflammatory factors were detected by ELISA. Moreover, western blot was applied to analyze the expression of proteins in transforming growth factor beta1 (TGFβ1)/SMAD signaling. Results revealed that mice in the model group showed obvious behavioral changes. Lrg1 was highly expressed in the brain tissues of model mice. Besides, Lrg1 knockdown suppressed the inflammation and apoptosis of LPS-induced HT22 cells. Moreover, Lrg1 silencing caused the inactivation of TGFβ1/SMAD signaling. Rescue assays confirmed that TGFβ1 overexpression reversed the impacts of Lrg1 deletion on the inflammation and apoptosis in LPS-induced HT22 cells. Collectively, Lrg1 silencing alleviates brain injury in SAE via inhibiting TGFβ1/SMAD signaling, implying that Lrg1 might serve as a promising target for SAE treatment.

AIM: To investigate microvascular changes in eyes with central retinal vein occlusion (CRVO) complicated by macular edema before and after intravitreal conbercept injection and evaluate correlations between these changes and best-corrected visual acuity (BCVA) and retinal thickness. METHODS: Twenty-eight eyes of 28 patients with macular edema caused by CRVO were included in this retrospective study. All patients received a single intravitreal conbercept injection to treat macular edema. BCVA and the results of optical coherence tomography angiography (OCTA) automatic measurements of the vessel density in the superficial (SCP) and deep retinal capillary plexus (DCP), the foveal avascular zone (FAZ) area, the FAZ perimeter (PERIM), the vessel density within a 300-μm wide ring surrounding the FAZ (FD-300), the acircularity index (AI), the choriocapillaris flow area, and retinal thickness were recorded before and at one month after treatment and compared with the results observed in age- and sex- matched healthy subjects. RESULTS: The vessel density in the SCP and DCP, the FD-300, and the flow area of the choriocapillaris were all significantly lower in CRVO eyes than in healthy eyes, while the AI and retinal thickness were significantly higher (all P

Purpose: To quantitatively evaluate microvascular changes in eyes with macular oedema due to branch retinal vein occlusion (BRVO) using optical coherence tomography angiography (OCTA) before and after intravitreal conbercept injection and the correlation of such changes with best-corrected visual acuity (BCVA) and retinal thickness. Methods: Twenty-eight eyes of 28 patients treated with a single intravitreal injection of conbercept for macular oedema due to BRVO were included in this study. The automatically measured values of the vessel density in the superficial (SCP) and deep retinal capillary plexus (DCP), the foveal avascular zone (FAZ) area, the FAZ perimeter, the vessel density within a 300 μm wide ring surrounding the FAZ (FD-300), the acircularity index (AI), the choriocapillaris flow area and the retinal thickness were obtained via OCTA before and at 1 month after initial injection and compared with those of age- and sex- matched healthy subjects. Results: In BRVO eyes, the vascular density in the SCP and DCP, the FD-300 and the flow area of choriocapillaris were significantly lower than those in healthy eyes, while the AI and the retinal thickness were significantly increased. After treatment, the retinal thickness in eyes with BRVO was significantly decreased in all quadrants, and the mean BCVA dramatically increased from 20/162 to 20/78 (p = 0.0017). The mean flow area of choriocapillaris significantly improved after treatment. Moreover, negative correlations between the logMAR BCVA and the whole vascular density in the SCP and DCP as well as the flow area of choriocapillaris were observed. Conclusion: OCTA enables non-invasive, layer-specific and quantitative assessment of microvascular changes in eyes with BRVO before and after treatment, and it can be used as a valuable imaging tool for the evaluation of the follow-up in BRVO patients.

Background: We aimed to investigate the high-risk factors of stroke through logistic regressive analysis and using LightGBM algorithm separately. The results of the two models were compared for instructing the prevention of stroke. Methods: Samples of residents older than 40 years of age were collected from two medical examination centers in Jiaxing, China from 2018 to 2019. Among the total 2124 subjects, 1059 subjects were middle-aged people (40-59 years old) and 1065 subjects were elder-aged people (≥60 years old). Their demographic characteristics, medical history, family history, eating habits etc. were recorded and separately input into logistic regressive analysis and LightGBM algorithm to build the prediction models of high-risk population of stroke. Four values including F1 score, accuracy, recall rate and AUROC were compared between the two models. Results: The risk factors of stroke were positively correlated with age, while negatively correlated with the frequency of fruit consumption and taste preference. People with low-salt diet were associated with less risk of stroke than those with high-salt diet, and male had higher stroke risk than female. Meanwhile, the risk factors were positively correlated with the frequency of alcohol consumption in the middle-aged group, and negatively correlated with the education level in the elder-aged group. Furthermore, the four values from LightGBM were higher than those from logistic regression, except for the recall value of the middle-aged group. Conclusion: Age, gender, family history of hypertension and diabetes, the frequency of fruit consumption, alcohol and dairy products, taste preference, and education level could as the risk predictive factors of stroke. The Model of using LightGBM algorithm is more accurate than that using logistic regressive analysis.

Traditional copyright protection technologies are unable to adapt to the current digital era of the Internet, and some problems such as difficult in digital works confirmation copyright, complex copyright transactions, copyright protection and infringement monitoring. Although Digital Rights Management (DRM) can provide certain security for digital copyrights, it still cannot effectively solve these problems. The decentralization, non-tampering, traceability and other characteristics of the blockchain are of great help to address the above problems. This paper proposes a scheme combining blockchain technology with digital rights management, and builds a digital rights management platform based on blockchain. In this paper, we propose platform system architecture based on blockchain technology by using the open source Hyperledger Fabric framework as the underlying blockchain development platform and combining smart contracts, IPFS systems, timestamps and other technologies, and have implemented the functions of the four core modules of the platform, which brings new breakthroughs for digital copyright protection technology.

PURPOSE: To evaluate pre-operative and post-operative morphologic characteristics in idiopathic macular epiretinal membrane (ERM) by optical coherence tomography angiography (OCTA). METHODS: Thirty-three subjects with unilateral idiopathic ERM were enrolled and the contralateral eyes served as controls. Vascular parameters including superficial capillary plexus (SCP), deep capillary plexus (DCP), outer capillary plexus (OCP), and choroidal capillary plexus (CCP) were evaluated by OCTA. RESULTS: The superficial foveal avascular zone (FAZ) was significantly smaller in eyes with ERM (P

In the virtual simulation training system for interventional surgery, most people focus on how to model blood vessel, catheter and guide wire. However, little research has been done on the effect of intravascular blood on interventional surgery. Blood is a kind of viscous fluid, so as the catheter or guide wire advances, retreats, or rotates through the blood vessel, the blood produces a kind of viscous force in the movement of the catheter or guide wire. It can affect the accuracy of the operation. In order to realize real simulation, firstly, the Smoothed Particle Hydrodynamics (SPH) method is applied to the study to simulate physical blood flow. Secondly, the Marching Cube method is adopted to render physical model, which can establish a good blood flow model. The method can also be used to simulate bleeding on organs or skin surfaces. Finally, we achieve the blood flow in blood vessel which is modeled by tensor - mass method. The experimental results show that the SPH method for blood simulation has a very real effect, and the simulation of intravascular blood flow is of great significance for the further study of interventional surgery.

Minimally invasive surgery (MIS) is an emerging technique, which is widely used and studied for computer-assisted training. The cooperation of the catheter and the guidewire is an essential part during the MIS procedure, which is not fully paid attention to but anatomic vascular deformation simulation. In this paper, a novel simulator integrated with a complete strategy for the cooperation of the catheter and the guidewire is proposed. A composite model of the physically based catheter and the guidewire, which are mapped to distinguished visual model and collision model of these two devices, is constructed at the initial point in the aorta vessels. Once it comes into the neurovascular cavity, the composite model is decomposed to two physically based model corresponding to the catheter and the guidewire respectively. Thereafter, the guidewire is operated and propelled through the catheter, which is fixed in position. The results show that the composite model exhibits equivalent efficiency and effectiveness as well as the separate catheter model, especially at the bifurcation of the vessels. The simulator proposed herein provides a fundamental module meeting the real-time and realistic requirements of our endovascular interventional surgery training system.

Mass Spring Model (MSM) and Finite Element Method (FEM) are two basic methods for soft model deformation simulation. However, MSM has a high computation efficiency but low accuracy which is only a coarse approximation of the real biological soft tissue while FEM is inverse on the two sides. To achieve realistic and real-time simulation at the same time, in this paper, we proposed an improved non-linear elastic tensor-mass modelling method, which realizes fast computation of non-linear mechanical deformations, and it is suitable for simulating the hollow biological tissue surface. Based on the tensor-mass concept, we applied the tensors of triangles to the surface vessel model, which is distinguished from the current study of tetrahedral tensors while simulating solid tissue, such as liver. Also, we applied an extension of an efficient implicit numerical analytical method for the simulation. Moreover, we introduced a haptic force feedback device for interactions between the vessel model and the virtual medical instrument which improves the realism of the simulation. A set of experiments, including the interactive deformation of the physical vessel model, and the stress-strain data analyses of different nodes and a single node, were conducted to validate the realism, accuracy, steadiness of the TMM model during the simulation. The simulation results showed high efficiency and real time performance over 91 fps which is about 30% higher than the current realistic simulation method in the training system.

Well-Structured Pushdown Systems (WSPDSs) are pushdown systems extended with states and stack alphabet to be vectors, for modeling (restricted) recursive concurrent programs. It has been considered to be “very close to the border of undecidability”. In this paper, we prove some hardness results for the coverability problem of WSPDSs. We show that for WSPDS with three dimensional vectors as states and WSPDS with three dimensional vectors as stack alphabet, the coverability problem becomes Ackermann-hard.

Minimally invasive surgery is a specialized surgical technique that permits vascular interventions through very small incisions. It minimizes the patient's trauma and permits a faster recovery compared to traditional surgery. Although traditional invasive surgery training system can complete general training work, real-time performance and accuracy of most training system failed to meet the requirements of training work. Therefore, in this study, three parts, including 3D modeling, collision detection algorithm and application architecture were improved in the existing training system. Firstly, an improved Marching cubes algorithm was adopted to simplify the mathematical modeling of vessels by merging the related points of the mesh model. Secondly, a hybrid collision detection algorithm was proposed and implemented. Lastly, the CPU-GPU parallel computing architecture was adopted. Particularly, the design of the improved VR-based system and the experimental results were presented and analyzed. Moreover, experimental results showed that the proposed system was beneficial to improve the skill of surgeons in manipulating the catheter and guide wire. Thus, the simulators could be used for trial surgery training.

Timed automata are commonly recognized as a formal behavioral model for real-time systems. For compositional system design, parallel composition of timed automata as proposed by Larsen et al. [22] is useful. Although parallel composition provides a general method for system construction, in the low level behavior, components often behave sequentially by passing control via communication. This paper proposes a behavioral model, named controller automata, to combine timed automata by focusing on the control passing between components. In a controller automaton, to each state a timed automaton is assigned. A timed automaton at a state may be preempted by the control passing to another state by a global labeled transition. A controller automaton properly extends the expressive power because of the stack, but this can make the reachability problem undecidable. Given a strict partial order over states, we show that this problem can be avoided and a controller automaton can be faithfully translated into a timed automaton.

Background Physics-based vascular modelling is an essential issue to be addressed in the development of the endovascular interventional surgery training system, which helps to shorten the training period of novice surgeons to obtain dexterous skills of surgical operation. Methods A blood vessel model based on tensor-mass method (TMM) is formulated and implemented in this context. A multimodel representation is adopted for the vascular model, including the mechanical, visual, and collision model. Triangular and tetrahedral TMM are formulated and implemented in Simulation Open-source Framework Architecture (SOFA). An extensional formulation and analysis of two typical methods are implemented in SOFA. Meanwhile, a set of experiments were conducted to test the refresh rate, the stability, and the visual realism of the vascular deformation simulation, integrating with TMM, mass-spring model, and finite element method. Results The experimental and subjects' testing results prove that TMM outperforms the current physically based methods in realistic and real-time vascular deformation simulation, which provides a refresh rate up to 256 frame per second on a triangular vascular topology. Conclusions The vascular model presented herein provides a fundamental module meeting the real-time and realistic requirements of our endovascular interventional surgery simulator.

Both the patents issued and applications filed in China regarding nickel/metal hydride (Ni/MH) battery technology are reviewed in the article. Selective works from 39 battery manufactures, 9 metal hydride alloy suppliers, 13 Ni(OH)2 suppliers, 20 hardware suppliers, 19 system integrators, universities, and 12 research institutes are included. China being the country that produces the most Ni/MH batteries is relatively weak in the innovation part of intellectual properties when compared to the US and Japan. However, it produces very many patents in the areas of cell structure optimization and production processes. Designs of high-capacity, high-power, and low-cost cells are compared from different manufacturers.

This paper proposes a new timed model named nested timed automata (NeTAs). A NeTA is a pushdown system whose stack symbols are timed automata (TAs). It either behaves as the top TA in the stack, or switches from one TA to another by pushing, popping, or changing the top TA of the stack. Different from existing component-based context-switch models such as recursive timed automata and timed recursive state machines, when time passage happens, all clocks of TAs in the stack elapse uniformly. We show that the safety property of NeTAs is decidable by encoding NeTAs to the dense timed pushdown automata. NeTAs provide a natural way to analyze the recursive behaviors of component-based timed systems with structure retained. We illustrate this advantage by the deadline analysis of nested interrupts.