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Rechargeable aqueous zinc-ion batteries (AZIBs) have captured a surge of interest in recent years as a promising alternative for scalable energy storage applications owing to the intrinsic safety, affordability, environmental benignity, and impressive electrochemical performance. Despite the facilitated development of this technology by many investigations, however, its smooth implementation is still plagued by inadequate energy density and undesirable life span, which calls for an efficient and controllable cathode storage chemistry. Here, this review focuses on the key bottlenecks by offering a comprehensive summary of representative cathode materials and comparatively analyzing their structural features and electrochemical properties. Then, we critically present several feasible electrode design strategies to guide future research activities from a fundamental perspective for high-energy-density and durable cathode materials mainly in terms of interlayer regulation, defect engineering, multiple redox reactions, activated two-electron reactions, and electrochemical activation and conversion. Finally, we outline the remaining challenges and future perspectives of developing high-performance AZIBs.

Vanadium-based compounds with an open framework structure have become the subject of much recent investigation into aqueous zinc-ion batteries (AZIBs) due to high specific capacity. However, there are some issues with vanadium dissolution from a cathode framework as well as the generation of byproducts during discharge that should not be ignored, which could cause severe capacity deterioration and inadequate cycle life. Herein, we report several barium vanadate nanobelt cathodes constructed of two sorts of architectures, i.e., Ba1.2V6O16·3H2O and BaV6O16·3H2O (V3O8-type) and BaxV2O5·nH2O (V2O5-type), which are controllably synthesized by tuning the amount of barium precursor. Benefiting from the robust architecture, layered BaxV3O8-type nanobelts (Ba1.2V6O16·3H2O) exhibit superior rate capability and long-term cyclability owing to fast zinc-ion kinetics, enabled by efficiently suppressing cathode dissolution as well as greatly eliminating the generation of byproduct Zn4SO4(OH)6·xH2O, which provides a reasonable strategy to engineer cathode materials with robust architectures to improve the electrochemical performance of AZIBs.

Background Celastrol (CEL), a triterpene extracted from the Chinese herb tripterygium wilfordii, has been reported to have profound anticancer activities. However, poor water solubility and high side toxicities have severely restricted the clinical applications of CEL. Purpose We proposed a facile "in situ drug conjugation-induced self-assembly" strategy to prepare CEL-loaded nanoparticles (CEL-NPs) that exhibited enhanced antitumor activity against melanoma. Methods First, the CEL was chemically conjugated onto a methoxyl poly(ethylene glycol)-b-poly(L-lysine) (mPEG-PLL) backbone, resulting in the conversion of the double hydrophilic mPEG-PLL polymer into an amphiphilic polymer prodrug, mPEG-PLL/CEL. The obtained mPEG-PLL/CEL could self-assemble into stable micelles in aqueous solution due to the hydrophobic association of CEL moieties in the side chains and the possible electrostatic interaction between the carboxyl group in CEL and the residue amine group in the PLL segment. Thus, the obtained mPEG-PLL/CEL nanoparticles were named CEL self-stabilized nanoparticles (CEL-NPs), which were then characterized by dynamic light scattering and transmission electron microscopy. Furthermore, the antitumor effects of the CEL-NPs were investigated by an MTT assay in vitro and in a B16F10 tumor-bearing mice model. Results The CEL-NPs exhibited sustained drug release behavior and were effectively endocytosed by B16F10 cells. Furthermore, the in vivo antitumor evaluation demonstrated that the CEL-NPs had remarkably higher tumor growth inhibition rates and lower systemic side effects than free CEL. Conclusion In summary, our present work not only demonstrates the generation of stable CEL-loaded nanoparticles for the efficient treatment of melanoma but also describes a general way to prepare drug self-stabilized nanomedicine for anticancer therapy.

The damage properties of carbon fiber reinforced polymer (CFRP) laminates exposed to combined lightning components D and C were explored by standardized artificial lightning tests, and then evaluated by visual inspection and ultrasonic scan. To interpret the heating mechanism of CFRPs under the combined lightning components D and C, a mathematical model of lightning arc was involved in the finite element analysis, the results of which agreed well with experimental data. It was revealed that the component D controlled the in-plane damage area, while the sequential injection of component C aggravated the in-plane damage extent and tended to induce in-depth damage. The simulated results indicated that the resistive heating effect played a leading role in thermal damage of CFRPs during component D, whereas the damage occurred in component C was dominated by lightning arc heating effect.

The stiffener plays an important role in the overall performance of T-stiffened skin assembly which is a primary structure of aircraft. In this paper, a thermo-viscoelastic finite element model tha...

This paper synergistically addressed the microstructure alteration and the mechanical behavior of rubber during thermo-oxidative aging process from both experimental and numerical modeling aspects. Through the FTIR spectra analysis, equilibrium swelling experiment, low-field NMR measurement and mechanical tests of styrene-butadiene rubber (SBR) samples, a macromolecular network alteration mechanism was introduced. The mechanism is related to the variation of the crosslinking network and dangling chain ends of SBR during aging. A finite deformation based hyper-viscoelastic constitutive model was then established to capture the mechanical behavior of SBR during aging. Based on the interpretation of the microscopic mechanism, the above-mentioned network alterations during aging were considered in the model. After the implementation by means of the finite element simulation software ABAQUS, the accuracy of the established model was checked via the comparison of the numerical results with the corresponding data obtained from mechanical tests. The work is helpful for estimating rubber mechanical performance during aging process.

In order to investigate the influence of anticorrosion-used fiberglass isolation layer on the lightning strike protection (LSP) of carbon fiber reinforced plastic (CFRP), the specimens, prepared by inserting a fiberglass layer between the expanded metal (Al or Cu) foil and CFRP substrate, were subjected to the artificial lightning of standardized Waveform C (200 Coulombs) and Waveform D (100 kA). The post-lightning damage was evaluated via visual inspection, ultrasonic scanning and residual strength test. The experiments found that the fiberglass isolation layer enhanced the LSP effectiveness of CFRP. While the majority of LSP solutions are based on the current “discharge” mechanism of highly conductive materials, the fiberglass isolation layer probably belongs to the “isolating” mechanism. The inherent electrically insulating, thermally insulating and refractory properties of fiberglass make it possible to construct an isolation layer that suppresses the downward penetration of lightning electric and heat into the underlying CFRP, preventing the CFRP from being ablated by internal Joule heat and external heat.

Our aim was to characterize health beliefs about the human papillomavirus (HPV) vaccine in a large set of Twitter posts (tweets). We collected a Twitter data set related to the HPV vaccine from 1 January 2014, to 31 December 2017. We proposed a deep-learning-based framework to mine health beliefs on the HPV vaccine from Twitter. Deep learning achieved high performance in terms of sensitivity, specificity, and accuracy. A retrospective analysis of health beliefs found that HPV vaccine beliefs may be evolving on Twitter.

In order to investigate the lightning strike protection (LSP) effectiveness of expanded foils, the carbon fiber reinforced polymer (CFRP) composites with copper or aluminum expanded foil surface layers were subjected to standardized Waveform D (100 kA). The results demonstrated the excellent performance of the expanded foils in suppressing the heavy lightning strikes. Importantly, the damage morphology of post-lightning specimens indicated that the electrical conductivity of expanded foils was anisotropic, which was confirmed by numerical simulation. The anisotropic conductive expanded foils can highly enhance LSP effectiveness if their laying directions are optimally designed according to aircraft lightning zoning by SAE ARP 5414. Taking the expanded foil as an example, the study proposed a novel method to enhance LSP effectiveness for CFRP-based aircraft by optimally designing the laying directions of the LSP layers with anisotropic electrical conductivity.

Rechargeable aqueous zinc-ion batteries have shown great potential for grid-scale applications owing to their high safety, low cost and sustainability. However, they are still limited by the lack of suitable cathode materials with high energy density and satisfactory cycling stability. Herein, a highly reversible zinc-ion battery system with (NH4)2V6O16·1.5H2O nanobelts as the cathode materials and aqueous ZnSO4 solution as the electrolyte has been developed. The (NH4)2V6O16·1.5H2O nanobelts deliver a superior reversible specific capacity of 479 mA h g−1 at 0.1 A g−1 with a desirable energy density of 371.5 W h kg−1 and exhibit an impressive cycling stability, i.e. 152 mA h g−1 retained after 3000 cycles at 5 A g−1. The high energy density and long-term cycling stability make (NH4)2V6O16·1.5H2O a promising candidate for grid-scale energy storage. This work could be extended to choose and construct other ideal high-performance cathode materials for ZIBs and other multivalent metal ion storage systems.

By using standardized Waveforms C and D, this study explored the lightning strike protection (LSP) effectiveness of nickel coated carbon fiber nonwoven veils (Ni-CFNVs) on protecting the carbon fiber composite structures in Zone 2 (aircraft lightning zoning). The post-lightning damage was evaluated by visual inspection, ultrasonic scan and residual strength test. Results showed that the Ni-CFNV of 70 g/m2 eliminated lightning strike damage inflicted by both waveforms and it even performed better than the commercial expanded copper foil of 73 g/m2. Therefore, the Ni-CFNV will be a promising alternative to metal mesh for eliminating lightning strike damage to the structures in Zone 2. The remarkable LSP effectiveness of Ni-CFNV can be explained by its integration of high electrical conductivity of Ni-coating and prominent ablation resistance of carbon fiber. The experiments indicate that not only the electrical conductivity, but also the ablation resistance of LSP layer greatly influences the LSP effectiveness.

The degradation model of stiffness matrix containing thermal-mechanical coupling damage was constructed by the user-defined subroutine VUMAT on the basis of continuum damage mechanics (CDM) and phenomenological analysis method, then, it was introduced to the software ABAQUS/Explicit to simulate the damage caused by lightning induced effects of thermal ablation and expansion on carbon fiber reinforced polymer (CFRP) laminates. The results revealed the evolution of the coupling damage from the analysis of stress-strain state and damage variables involved. It can be concluded that the thermal-mechanical coupling model pushed the simulated in-plane damage much closer to the experimental results than thermal ablation model, and the good consistency of simulated in-depth damage and experimental results indicated that the lightning induced in-depth damage was mainly brought from the combined impacts of thermal ablation and expansion.

Using the mixed experimental/numerical method, the frequency-dependent transverse shear moduli (TSM) and damping values of the commercially available Nomex honeycomb cores were investigated. Four kinds of honeycomb cores with different phenolic resin thicknesses were used to explore the effect of the phenolic resin thickness on these dynamic mechanical properties. Results reveal that both the TSM and damping values have positive logarithmic relationships with the frequency, and the sensitivity of these dynamic mechanical properties to frequency is higher for the honeycomb core with thicker phenolic resin. Among all the transverse shear directions, TSM and damping values in the LT direction are the highest at medium and high frequencies. Compared with the damping values, the effect of phenolic resin thickness on TSM is more obvious. Therefore, it is a more efficient way to enhance the TSM than to improve the damping values by controlling the thickness of phenolic resin.

The characteristics of blood flow in an abnormal pediatric aorta with an aortic coarctation and aortic arch narrowing are examined using direct numerical simulations and patient-specific boundary conditions. The blood flow simulations of a normal pediatric aorta are used for comparison to identify unique flow features resulting from the aorta geometrical anomalies. Despite flow similarities compared to the flow in normal aortic arch, the flow velocity decreases with an increase in pressure, wall shear stress, and vorticity around both anomalies. The presence of wall shear stresses in the trailing indentation region and aorta coarctation opposing the primary flow direction suggests that there exist recirculation zones in the aorta. The discrepancy in relative flowrates through the top and bottom of the aorta outlets, and the pressure drop across the coarctation, implies a high blood pressure in the upper body and a low blood pressure in the lower body. We propose using flow manipulators prior to the aortic arch and coarctation to lower the wall shear stress, while making the recirculation regions both smaller and weaker. The flow manipulators form a guide to divert and correct blood flow in critical regions of the aorta with anomalies.

The hysteresis loss and the heat generation of rubber compounds under different ambient temperatures and frequencies were predicted in terms of the viscoelastic theory. The cross-linking densities and the dynamic compressive properties were measured in order to partially reveal the microstructures and the viscoelastic response of rubber specimens. Based on the experimental data of storage and loss moduli, a piecewise fitting method was established to determine the viscoelastic constitutive model parameters. Then the dynamic compressive process of natural rubber specimen was analyzed by the finite element method. The obtained hysteresis loss and the energy dissipation were used to predict the transient and steady-state temperature field. The results reveal that the dependence of rubber hysteresis loss on the frequency at a lower ambient temperature plays a more important role in predicting the heat generation of rubber compounds; the dependence becomes weaker as the ambient temperature increases.

Background Suicide has been one of the leading causes of deaths in the United States. One major cause of suicide is psychiatric stressors. The detection of psychiatric stressors in an at risk population will facilitate the early prevention of suicidal behaviors and suicide. In recent years, the widespread popularity and real-time information sharing flow of social media allow potential early intervention in a large-scale population. However, few automated approaches have been proposed to extract psychiatric stressors from Twitter. The goal of this study was to investigate techniques for recognizing suicide related psychiatric stressors from Twitter using deep learning based methods and transfer learning strategy which leverages an existing annotation dataset from clinical text. Methods First, a dataset of suicide-related tweets was collected from Twitter streaming data with a multiple-step pipeline including keyword-based retrieving, filtering and further refining using an automated binary classifier. Specifically, a convolutional neural networks (CNN) based algorithm was used to build the binary classifier. Next, psychiatric stressors were annotated in the suicide-related tweets. The stressor recognition problem is conceptualized as a typical named entity recognition (NER) task and tackled using recurrent neural networks (RNN) based methods. Moreover, to reduce the annotation cost and improve the performance, transfer learning strategy was adopted by leveraging existing annotation from clinical text. Results & conclusions To our best knowledge, this is the first effort to extract psychiatric stressors from Twitter data using deep learning based approaches. Comparison to traditional machine learning algorithms shows the superiority of deep learning based approaches. CNN is leading the performance at identifying suicide-related tweets with a precision of 78% and an F-1 measure of 83%, outperforming Support Vector Machine (SVM), Extra Trees (ET), etc. RNN based psychiatric stressors recognition obtains the best F-1 measure of 53.25% by exact match and 67.94% by inexact match, outperforming Conditional Random Fields (CRF). Moreover, transfer learning from clinical notes for the Twitter corpus outperforms the training with Twitter corpus only with an F-1 measure of 54.9% by exact match. The results indicate the advantages of deep learning based methods for the automated stressors recognition from social media.

Key thermophysical properties of the thermosetting resin, including density, conductivity coefficient and specific heat that evolve with resin curing, are related to temperature and curing degree fields of the fiber/resin composite material. However, their effects on heat transfer inside composite materials, consequently on the curing non-uniformity in thick-section laminates, are not well understood. The focus of this study is on the effects of key thermophysical properties of resin on the curing uniformity of AS4/3501-6 composite by means of the coupled thermochemical analysis with the method of numerical simulation. The results clearly indicate that the conductivity coefficient and specific heat of resin have obvious influence on curing uniformity, especially for thick laminates, while the density of resin has no noticeable effect on the curing uniformity. The simulation results can help to guide the material preparation of industrial production.

Hierarchical birnessite-type manganese oxide catalysts modified by transition metal (cobalt, cerium, copper, and nickel) cations were synthesized via a facile hydrothermal reaction. The influence of doping elements on the structure and catalytic behavior of the as-prepared catalysts was thoroughly investigated by characterization techniques such as XRD, SEM, TEM, BET, ICP-OES, XPS, FT-IR, TGA, H2-TPR and O2-TPD. The results indicated that the doping of different transition metal cations was found to hardly alter the phase structures and morphologies of the as-obtained birnessite, but displayed distinct differences in catalytic activity for CO oxidation. The doping of Ce(III) and Cu(II) remarkably promoted the catalytic performance while Co(II) and Ni(II) induced a passive effect on the activity. Ce–MnO2 exhibited superior CO oxidation activity at lower temperatures with T50 = 146 °C and T90 = 175 °C in comparison with the pristine birnessite, while Cu–MnO2 possessed the best activity at a relatively low temperature below 120 °C with Tlight-off = 65 °C. The mobility and reducibility of lattice oxygen were found to be the determinants for CO oxidation, in substantial correlation with the generation of surface oxygen vacancies and activation of lattice oxygen species. These features could be mostly ascribed to the formation of synergistic Ce–Mn and Cu–Mn interactions in their respective lattice oxides, however, in different ways.

A three-dimensional differential viscoelastic model combining the effects of curing degree, thermal expansion, chemical shrinkage and stress relaxation for composite laminates was established and well verified. The evolution of strain and stress of composite laminates during cure was numerically simulated using the validated model. Also, fiber Bragg grating temperature and strain sensors were adjacently embedded in the composite laminate to in situ monitor the temperature and strain evolution. The monitored strain was evaluated by comparison with the corresponding simulated strain. The results reveal that the monitored temperature can reflect the actual temperature evolution in composite laminates, whereas the monitored strain cannot accurately characterize the actual strain evolution in composite laminates at the early stage of cure. However, when the resin/grating interfacial bond strength increases enough to transfer resin strain effectively, the changes in the monitored strain can match well with the actual strain changes.

In this article, a triphasic model is developed and the finite element method is adopted to research weak polyelectrolyte hydrogel. The influence of HCl concentrations in external solution on ion concentrations inside the hydrogel as well as the evolution of water volume fraction is discussed. The conservation of charge can be reached everywhere in the hydrogel. Besides, drug release equation which both considers the convection and diffusion effects is employed to analyze the drug release rate. The results show that the drug release rate has a very close relationship with the pH value. Afterwards, the simulated results are compared with experimental results of Beebe to validate the reliability and accuracy of this simulation. This work is significant in studying the oral drug controlled release in gastrointestinal tract.

Both temperature dependent model and pyrolysis dependent model were proposed to investigate the lightning strike damage of carbon fiber reinforced polymer (CFRP) composite laminates, where lightning in-plane and in-depth damages were evaluated by the two models, respectively. Firstly, the simulated results were compared with the experimental data of IM600/133 composites to determine the feasibility of the models. The results affirmed that lightning in-plane damage evaluated by temperature dependent model had a good agreement with experimental results while the lightning in-depth damage evaluated by pyrolysis dependent model matched well with experimental results. Then the proposed models and methods were confirmed by the simulation of the lightning strike damage of TR50S15L/YPH-308 laminates and the comparison between the simulated and experimental results. The appropriate models and methods to evaluate lightning in-plane and in-depth damages are helpful for the research of lightning damage behaviors, mechanisms and anti-lightning optimizations of CFRP.

The numerical model of carbon fiber reinforced polymer (CFRP) laminates with electrically modified interlayers subjected to lightning strike is constructed through finite element simulation, in which both intra-laminar and inter-laminar lightning damages are considered by means of coupled electrical-thermal-pyrolytic analysis method. Then the lightning damage extents including the damage volume and maximum damage depth are investigated. The results reveal that the simulated lightning damages could be qualitatively compared to the experimental counterparts of CFRP laminates with interlayers modified by nickel-coated multi-walled carbon nanotubes (Ni-MWCNTs). With higher electrical conductivity of modified interlayer and more amount of modified interlayers, both damage volume and maximum damage depth are reduced. This work provides an effective guidance to the anti-lightning optimization of CFRP laminates.

Background Disease comorbidity is very common and has significant impact on disease treatment. Revealing the associations among diseases may help to understand the mechanisms of diseases, improve the prevention and treatment of diseases, and support the discovery of new drugs or new uses of existing drugs. Methods In this paper, we introduced a mathematical model to represent gene related diseases with a series of associated genes based on the overrepresentation of genes and diseases in PubMed literature. We also illustrated an efficient way to reveal the implicit connections between COPD and other diseases based on this model. Results We applied this approach to analyze the relationships between Chronic Obstructive Pulmonary Disease (COPD) and other diseases under the Lung diseases branch in the Medical subject heading index system and detected 4 novel diseases relevant to COPD. As judged by domain experts, the F score of our approach is up to 77.6%. Conclusions The results demonstrate the effectiveness of the gene fingerprint model for diseases on the basis of medical literature.

High-safety and low-cost aqueous Zn-ion batteries have triggered an astounding investigation surge in the last 5 years and are becoming competitive alternatives for grid-scale energy storage. However, the implementation of this promising technology is still plagued by the lack of effective and affordable cathode materials that can enable high energy densities and an exceptional cycling stability. Herein, a novel vanadium-based oxide cathode based on MgV2 O6 ·1.7H2 O nanobelts, which delivers a high capacity (425.7 mAh g-1 at 0.2 A g-1 ), a robust rate capability (182.1 mAh g-1 at 10 A g-1 ), and an ultrastable cycle without any visible deterioration, as well as an adequate energy density (331.6 Wh kg-1 ), is developed. Such excellent electrochemical Zn-ion storage performance is believed to result from the fast ion-diffusion kinetics boosted by a stable layered structure and an ultrahigh intercalation pseudocapacitance reaction, which are also benefited by a typical H+ /Zn2+ co-insertion mechanism, accompanied by an atypical Zn2+ intercalation chemistry with a partial but irreversible Mg2+ -Zn2+ ion-exchange reaction during the initial discharge. These results provide key and enlightening insights into the design of high-performance vanadium oxide cathode materials.

The realization of detection of carbon dioxide (CO2) is important for environmental protection. A critical challenge is how to fabricate low-cost fiber Bragg grating (FBG) sensor. Here, a new type of polyether sulfone (PES)-coated FBG sensor for CO2 detection is reported to address this challenge. The PES coating exhibits volume dilation in CO2 exposure and can transfer the stress to the grating, causing changes of the period and the refractive index of the grating. The uniform and smooth PES coating is critical for the repeatability and reliability of the sensor, which is realized through the low-temperature spin coating and high-temperature curing. The influence factors and the performance of the FBG sensor were investigated. The maximum Bragg wavelength shift is positively related to coating thickness and negatively related to temperature. The PES-coated FBG sensor possesses good selectivity to CO2 and the minimum response time is 3.27 min. The limit of detection (LOD) can be down to 0.78 % for CO2 detection. Finally, an over-concentration alarm system for on-line CO2 monitoring was developed. The outstanding features of the PES-coated FBG sensor with low-cost and simple fabrication process provide widely prospect in applications.

For predicting the mechanical properties of discontinuous carbon fiber-reinforced thermoplastics (DCFRTP), it is essential to consider the microstructure, including the fiber orientation and the properties of the constituting materials. In the present study, a heterogeneous particle model, considering the microscopic factors, is constructed on the basis of the peridynamic (PD) theory to investigate the tensile properties of DCFRTP. Two kinds of randomly oriented DCFRTP, with different constituents and volume fractions of carbon fiber, are used for the verification of this numerical model. A comparison between the PD simulations and the experimental results shows a good agreement. The effect of the model size on the prediction is discussed.

Accurate debonding identification is essential for subsequent structural repair, however, the research on debonding identification on both sides of the symmetrical honeycomb sandwich structures by means of the vibration-based method faces certain challenges. To address this, a two-step strategy based on the uniform load surface (ULS) curvature method is presented. Specifically, the potential debonding area is first identified through the global debonding detection of the entire sandwich structure. Then, the specific debonding information on both sides is identified by introducing the local constraint to the boundary of the above potential debonding area. The corresponding mechanism is that the local constraint improves the relative vibration amplitude of debonded skin. On this basis, further study on the applicable scope of the ULS curvature method indicates that the debonding of Nomex honeycomb sandwich structures with relatively low-modulus skin and large honeycomb core phenolic resin thickness is relatively easy to be identified. This work is helpful to guide the precise debonding detection of honeycomb sandwich structures.

The damage of carbon fiber reinforced polymer (CFRP) laminated composites under lightning strike is analyzed by coupled electrical–thermal-pyrolytic models, which is implemented by the ABAQUS/Standard finite element code coupled with user-defined subroutines USDFLD and HEATVAL. To clarify the effects of the lightning current waveform parameters and the thermal/electrical properties of CFRPs, the damages of CFRP laminated specimens under diverse lightning current waveforms are experimentally and numerically analyzed. The results reveal that the damage volume shows a strong logarithmic relationship with the action integral, and that the damage is strongly governed by the electrical properties of CFRPs, though thermal conductivity variation barely affects the damage volume.

Curing process-induced internal stress and deformation are major problems that restrict the wildly used of carbon fiber/epoxy composites in aerospace and vehicle industry. The finite element simulations of the evolution of cure-induced internal stress and curing deformation of the AS4/3601-6 composites are carried out using both elastic and viscoelastic models. The differences between these two kinds of numerical results are analyzed. The numerical results show that the difference between the two decreases with the increase of the fiber volume fraction or the decrease of the resin curing shrinkage. The comparative analysis is helpful for clearly understanding the deformation mechanism and then optimally designing the processing conditions in accordance with the specific needs.

In different parts of the gastrointestinal tract, the rate of drug release from polyelectrolyte hydrogel tablets is highly affected by variance of ionic concentration. This research aims at revealing clearly how the drug release from a hydrogel matrix is affected by ionic concentration of external solution through the finite element simulation and triphasic mechanism model. The coupled relationship of the motions including the polyelectrolyte hydrogel swelling, the water flow and the ion diffusion, is illustrated in the present work. In order to simulate the drug controlled release from a swollen polyelectrolyte hydrogel carrier, the mathematical model was built on the basis of the multiphasic theory of polyelectrolyte hydrogels. Finally, the reliability of the simulation method was verified qualitatively by experimental results. The results reveal that when the initial concentration of fixed anions of polymer network is higher than the concentration of free anions in the external solution, the drug release rate increases with increasing the ionic concentration of the external solution. The research is helpful for the optimal design of oral drug release in gastrointestinal tract.

Background As the second-largest economy in the world, China has invested considerable financial and policy support into hospital informatization since health care reform in 2010. However, the results and experience of such investments have not been compared with relevant research and applications in the United States and Europe. Objectives From the perspective of professional conference proceedings, we comparatively analyzed the current situations, characteristics, hotspots, and trends of medical informatics (MI) development in China, the United States and Europe to help Chinese MI researchers and practitioners summarize their experiences and determine gaps compared to their American and European peers. We also aimed to educate foreign peers about the special contributions of the China MI circle and facilitate multilevel international cooperation. Methods English conference proceedings of the American Medical Informatics Association (AMIA) Annual Symposium (USA), Medical Informatics Europe (MIE, Europe) and World Conference on Medical Informatics (MEDINFO, Global) from 2007 to 2017 were searched within Scopus and Pubmed. Proceedings of Chinese MI conferences (CMIAAS, CHINC, CHITEC, CPMI) (China) were searched within Chinese databases CQVIP, CNKI and WanFang during the same period. The datasets were preprocessed via a Natural Language Processing (NLP) package on Python and were qualitatively and quantitatively analyzed via bibliometric methods. Results Overall, 2285, 1601, 1930 and 5431 papers were publicized from the AMIA Symposium (USA), MIE (Europe), MEDINFO (Global) and Chinese MI conferences (China) between 2007 and 2017, respectively, with an H-index of 32, 19, 19 and 3, respectively. The AMIA Symposium, MIE and MEDINFO received submissions from 43, 68 and 80 countries (or regions), respectively, but Chinese MI conferences (CMIAAS, CHINC, CHITEC, CPMI) only received submissions from 3 foreign countries. Author affiliations were quite similar among the AMIA Symposium, MIE and MEDINFO, as 67%, 75% and 70% of authors came from universities/colleges, respectively; 18%, 10% and 11% came from medical institutions, respectively; and 7%, 8% and 10% came from institutes, respectively. In contrast, the majority (54%) of authors in Chinese MI conferences came from medical institutions followed by universities/colleges (17%) and institutes (10%). Of the top 5 authors with the most publications in AMIA Symposium, MIE and MEDINFO, 14/15 of them had medical backgrounds, but only one author from the Chinese MI conferences majored in medicine. Electronic medical records (EMR) were included in the top 10 high-frequency keywords by all four conference groups, but the amount of time that this keyword appeared differed in 2009, 2011, 2012 and 2013, respectively. Conclusions The MI annual conferences are all different among China, the United States and Europe. China lags in the theoretical and discipline bases but has made considerable investments in the past 10 years. China should fully use its second-mover advantage and application advantages and utilize international experiences and cooperation to make stronger contributions to global MI development.

Background There are many problems with fitness trackers, such as device usability, which limit their large-scale application, and relevant studies are limited in terms of their sample size and evaluation methods. The purpose of the study was to evaluate the perceived usability of various mainstream fitness trackers on the market, and to learn about user feedback on feature preferences for each device. Methods Trial use of seven mainstream fitness trackers (two smart watches and five smart wristbands) followed by a survey study were applied. The questionnaire was specifically developed for this study, which included two parts (user preferences and device usability in five dimensions). We recruited users to test the devices for at least 30 days and asked experienced users to provide feedback in order to evaluate each device, including the rating and user preference of each device. Results We received 388 valid questionnaires, in which users rated their responses on a five-point Likert scale. (1) User preference: the average user satisfaction was 3.50–3.86 (points), and the rating for willingness to buy averaged between 3.36 and 3.59. More users were willing to wear (58.3–81.3%) and purchase (56.8–83.0%) the devices than were not. The top three general feature preferences were daily activity tracking, heart health monitoring, and professional fitness tracking. The top three health-related feature preferences were heart rate monitoring, daily pedometer, and professional fitness tracking. (2) Usability evaluation: product design was rated from 3.57 to 4.00; durability, 3.63–4.26; ease of use, 3.70–3.90; added features, 3.30–3.83; and user-rated accuracy, 3.44–3.78. A significant difference was observed in the rating of product design and durability among the different devices (p < 0.05) score. Conclusions Users generally had positive subjective intent regarding fitness trackers but were less satisfied with their cost effectiveness. The users preferred health related features such as heart health monitoring, and professional fitness tracking. The rating of most of the current mainstream fitness trackers was fair with some significant differences among the devices. Thus, further improvement is needed.

It is a challenge to predict the permeability due to the complex correlation between the permeability and structural parameters of fabric preform. In this paper, the correlation between the in-plane permeability and the structural parameters of the non-crimped fabrics is investigated by using the finite element method. The effect of the intra-ply structural parameters and ply orientations on the in-plane permeability of the fabric preform is investigated. In addition, the influence of four structural parameters on the in-plane permeability is analyzed by the Morris method. The results show that the in-plane permeability is most sensitive to the distance between fiber bundles, while the semi-major axis length of the ellipse section of the fiber bundle is relatively insensitive. The order of the in-plane permeability of non-crimped fabrics preform with different ply orientations is as follows: [0]2 > [0/90] > [−45/45]. The present research is helpful to predict permeability and to further simulate resin filling process.

The intralaminar and interlaminar damages of U3160/3266 laminated composites toughened by polyamide nonwoven fabric (PNF) under low velocity impact are investigated through a numerical model which considers both the three-dimensional continuum damage mechanics (CDM) and the bilinear cohesive zone model (CZM). The analysis of the intralaminar damage is implemented by the ABAQUS/Explicit finite element code coupled with a user-defined subroutine VUMAT where the longitudinal failure, transverse matrix cracking, and nonlinear shear of the material are taken into account. Then the effects of the thickness and strength of PNF/3266 interlayer on the damage of composites are numerically analyzed. The results reveal that damage morphology can be simulated qualitatively compared to the experimental counterparts. With the decreasing interlayer thickness or the increasing interlayer strength, the damage area is effectively reduced. This work provides an effective model to predict the low velocity impact damage of composites, and is helpful for the optimization of interlayer toughened composites. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

The objective of this research is to put forward a toughening method by using the polyamide non-woven fabric (PNF) and investigate the Mode-I fracture toughness and delamination characteristic of the toughened CFRP laminates by performing the double cantilever beam test. The effect of PNF interlayer, which is formulated by a bilinear cohesive zone model, on the Mode-I fracture of U3160-PNF/3266 laminated composites is numerically analyzed. And the intralaminar damages are considered by using strength criteria and stiffness degradation law. The influences of PNF/3266 interlayer strength, U3160/3266 laminate thickness and initial crack length on the mechanical response of laminates are studied systematically. The work by combining the experiment and simulation is helpful for the optimal design of laminated composites used in aerospace and civil engineering.

Objective. To analyze and compare the usefulness of hypertension management APPs released in the Chinese market; to understand the general situations, characteristics, problems, and trends in hypertension management mHealth APPs; and to identify the gaps between mainland China products and non-mainland China products with the aim to provide recommendations for developers in industry and assist hypertensive patients in selecting suitable APPs.Methods. The hypertension management APPs available by October 2016 in China were analyzed from the perspective of data items and function usefulness. Sample sets were determined through PRISMA. An evaluation item set was developed based on the usability framework of TURF and theChinese Guideline for the Management of Hypertensionand used to quantitatively analyze the functionalities and data items collected from the sample APPs from the perspective of designers, users, and activity models.Results. Among the 73 Chinese-supported APPs, none of the hypertension management APPs could fully cover the usefulness item set (mean = 37.4%). Regarding the use of mobile terminal hardware, only cameras and positioning sensors are commonly used in information collection. Regarding the data items and services provided, the most commonly collected data are “demographic information” (88% versus 100%) and “vital signs” (76% versus 100%), but APPs developed in mainland China and non-mainland China provided significantly different services and profit-making patterns. Regarding data security and privacy protection, the APPs from mainland China provided far lower usefulness (31% versus 56%).Conclusions. mHealth APPs can promptly and efficiently acquire sign-related data by improving the professionality and scientificity of data about healthy living habits. APPs also improve the preventive usefulness of the collected data and bring about new opportunities for the management and control of hypertension. Other important research trends include privacy protection and data security.

Based on the continuum damage mechanics (CDM) and the cohesive zone model (CZM), a numerical analysis method for the evaluation of damage in composite laminates under low-velocity impact is proposed. The intraply damage including matrix crack and fiber fracture is represented by the CDM which takes into account the progressive failure behavior in the ply, using the damage variable to describe the intraply damage state. The delamination is characterized by a special contact law including the CZM which takes into account the normal crack and the tangential slip. The effect of the interlaminar toughness on the impact damage is investigated, which is as yet seldom discussed in detail. The results reveal that as the interlaminar fracture toughness enhances, the delamination area and the dissipated energy caused by delamination decrease. The contribution of normal crack and tangential slip to delamination is evaluated numerically, and the later one is the dominant delamination type during the impact process. Meanwhile, the numerical prediction has a good agreement with the experimental results. The study is helpful for the optimal design and application of composite laminates, especially for the design of interlaminar toughness according to certain requirements. POLYM. COMPOS., 2014. © 2014 Society of Plastics Engineers

A new numerical simulation method was proposed to predict the mechanical behavior of carbon fiber reinforced resin composites under low-velocity impact load. The impact damage evolution can be characterized in the form of energy dissipation which can be calculated through the new numerical model. The evolution mechanism of delamination was analyzed through distinguishing between the normal induced delamination and tangential slip induced delamination. The drop weight tests were conducted on composite laminates with five kinds of stacking sequence. Experimental analysis was also presented in this article. The damage area and distribution was investigated through ultrasonic C-scan. The prediction had a good agreement with the experimental results through the comparison of impact response. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44374.