Local bone metabolism balance regulation via double-adhesive hydrogel for fixing orthopedic implants

© 2021 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)The effective osteointegration of orthopedic implants is a key factor for the success of orthopedic surgery. However, local metabolic imbalance around implants under osteoporosis condition could jeopardize the fixation effect. Inspired by the bone structure and the composition around implants under osteoporosis condition, alendronate (A) was grafted onto methacryloyl hyaluronic acid (H) by activating the carboxyl group of methacryloyl hyaluronic acid to be bonded to inorganic calcium phosphate on trabecular bone, which is then integrated with aminated bioactive glass (AB) modified by oxidized dextran (O) for further adhesion to organic collagen on the trabecular bone. The hybrid hydrogel could be solidified on cancellous bone in situ under UV irradiation and exhibits dual adhesion to organic collagen and inorganic apatite, promoting osteointegration of orthopedic implants, resulting in firm stabilization of the implants in cancellous bone areas. In vitro, the hydrogel was evidenced to promote osteogenic differentiation of embryonic mouse osteoblast precursor cells (MC3T3-E1) as well as inhibit the receptor activator of nuclear factor-κ B ligand (RANKL)-induced osteoclast differentiation of macrophages, leading to the upregulation of osteogenic-related gene and protein expression. In a rat osteoporosis model, the bone-implant contact (BIC) of the hybrid hydrogel group increased by 2.77, which is directly linked to improved mechanical stability of the orthopedic implants. Overall, this organic-inorganic, dual-adhesive hydrogel could be a promising candidate for enhancing the stability of orthopedic implants under osteoporotic conditions.This work was supported by the National Key R&D Program of China (2020YFA0908200), National Natural Science Foundation of China (82120108017), Six talent peaks project in Jiangsu Province (WSW-018). This work was financed by Portuguese funds through FCT - Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior in the framework of the project “Institute for Research and Innovation in Health Sciences” UID/BIM/04293/2019.info:eu-repo/semantics/publishedVersio

Fluorescent semiconductor nanocrystals, a promising fluorescent anti-counterfeiting material for specialty paper

Fluorescent semiconductor nanocrystals, also called quantum dots (QDs), have unique electronic and optical properties. One of the most useful features of QDs is that whereas their absorption spectra are broad, their emission spectra are very narrow. Different QDs can emit different wavelengths of visible light under UV excitation. QDs as a fluorescent anti-counterfeiting material have been attracting great interest in the application of specialty papers, such as security paper, banknote paper, packaging paper, etc. An anti-counterfeiting technique using QDs is one of the newest achievements in the anti-counterfeiting field. In the long run, research and development in the area of QDs anti-counterfeiting will surely create many fruitful results

Water-Resistant Material from Recovered Fibers and Acrylic Emulsion Terpolymer

Styrene (SM), methyl methacrylate (MMA), and butyl acrylate (BA) were used to synthesize a polyacrylic emulsion by core-shell emulsion polymerization. The solid content of the emulsion reached 40% using reasonable reactive emulsifier contents and feeding modes. Then, the emulsion and a fiber were dispersed, coated, and dried together. Finally, fiber-based water-resistant material was successfully fabricated. The experimental results showed that under the conditions of a monomer mass ratio of 1:1:1 and a mass ratio of polyacrylic emulsion to fiber of 2:1, the Cobb value of the material reached 5.0 g/m2. The tensile strength, elongation, and breaking length were 7.4225 kN/m, 1.0%, and 11.706 km, respectively. Using scanning electron microscopy (SEM) to analyze the surface morphology and internal structure of products, the reasons for the high water resistance of fiber-based material was due to the bonding and filling effects of the polyacrylic emulsion on the fibers. For tightly bound fibers, the porous structures formed in fiber-based boards were reduced. On the other hand, the polyacrylic emulsion filled the gaps between fibers. This filling effect led to a continuous structure, and the water resistance of the material was further enhanced

A Secure User Authentication Scheme against Smart-Card Loss Attack for Wireless Sensor Networks Using Symmetric Key Techniques

User authentication in wireless sensor networks (WSNs) is a critical security issue due to their unattended and hostile deployment in the field. In order to protect the security of real-time data query from an external user, many two-factor (password and smart-card) user authentication schemes are proposed. However, most of them are insecure against various attacks. This paper summarizes attacks and security requirements for two-factor user authentication in WSNs. Based on security requirements, a user authentication and session key establishment scheme is also proposed, and this scheme can resist smart-card loss attack merely by using symmetric key techniques. Security and performance analysis demonstrate that, compared to the existing schemes, the proposed approach is more secure and highly efficient

Preparation and Characterization of Lignin-based Membrane Material

Lignin-based membrane material was prepared from lignosulfonate extracted from sulfite pulping. The effects of formaldehyde, polyvinyl alcohol (PVA), urea, borax, glutaraldehyde (GD), and dimethyl phthalate (DMP) on tensile strength and water absorption were investigated. The experimental results showed that the optimum conditions were as follows: a reaction temperature of 85 °C, 22.22 wt.% lignosulfonate, 1.59 wt.% borax, 22.22 wt.% urea, 31.75 wt.% formaldehyde, 22.22 wt.% PVA, 32.32 wt.% GD (to PVA glue), and 32.32 wt.% DMP (to PVA glue). Under these conditions, the tensile strength reached 2.2 ×104 Pa and the water absorption was 35.2%. The products were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that the product components were compatible in this system, and the introduction of cross-linking agents may have resulted in a decrease in pore size

CBD: A Deep-Learning-Based Scheme for Encrypted Traffic Classification with a General Pre-Training Method

With the rapid increase in encrypted traffic in the network environment and the increasing proportion of encrypted traffic, the study of encrypted traffic classification has become increasingly important as a part of traffic analysis. At present, in a closed environment, the classification of encrypted traffic has been fully studied, but these classification models are often only for labeled data and difficult to apply in real environments. To solve these problems, we propose a transferable model called CBD with generalization abilities for encrypted traffic classification in real environments. The overall structure of CBD can be generally described as a of one-dimension CNN and the encoder of Transformer. The model can be pre-trained with unlabeled data to understand the basic characteristics of encrypted traffic data, and be transferred to other datasets to complete the classification of encrypted traffic from the packet level and the flow level. The performance of the proposed model was evaluated on a public dataset. The results showed that the performance of the CBD model was better than the baseline methods, and the pre-training method can improve the classification ability of the model

Adsorption kinetics of platinum group elements onto macromolecular organic matter in seawater

Adsorption kinetics of the interaction between Pt, Pd and Rh (defined here as platinum group elements, PGEs) ions and macromolecular organic compounds (MOCs, >10 kDa), including humic acid, carrageenan and bovine serum albumin, and different cutoff fractions of natural organic matter (>1 kDa and >3 kDa) obtained from seawater using centrifugal ultrafiltration devices were investigated. For a given element, all the adsorption kinetics did not reach equilibrium except the interaction between Pt and >1 kDa cutoff, and between Pd and humic acid. For all the tested MOCs, the adsorption kinetics could be divided into two stages, a rapid adsorption process in the first 8 h and the desorption stage after the first 8 h until the equilibrium. The change trend of partition coefficient (log_(10)K_d) values with experiment time was consistent with that of the kinetic curves. However, in the interaction between PGE ions and natural dissolved organic matter (NDOM), an obvious difference in the change trends of log_(10)K_d and kinetic curves was observed. It indicated that the partition behavior of PGE ions interacting with NDOM in seawater was a combined effect of different organic constituents. The adsorption and log_(10)K_d of PGEs in the >1 kDa NDOM fraction were higher and more stable than those in the >3 kDa NDOM fraction. The results also indicated that the 1–3 kDa NDOM may dominate the interaction between PGEs ions and NDOM. Moreover, no kinetic model could perfectly simulate the adsorption process. It indicated that the colloidal struction and morphology of MOCs or NDOM in seawater might be inhomogeneous. Hence, the interaction between PGE ions and organic matter in seawater was a complicated process and needs further research

Morphology and Crystal-Plane Effects of Fe/W-CeO2 for Selective Catalytic Reduction of NO with NH3

The CeO2 ordinary amorphous, nanopolyhedrons, nanorods, and nanocubes were prefabricated by the hydrothermal method, and employed as carriers of Fe/W–CeO2 catalysts to selectively catalyze the reduction of NO with ammonia. Characterization results indicated that the morphology of CeO2 support originated from selectively exposing different crystal surfaces, which has a significant effect on oxygen vacancies, acid sites and the dispersion of Fe2O3. The CeO2 nanopolyhedrons catalyst (Fe/W–CeO2–P) showed most oxygen vacancies, the largest the quantity of acid sites, the largest BET (Brunauer-Emmett-Teller) surface area and the best dispersion of Fe2O3, which was associated with predominately exposing CeO2 (111) planes. Consequently, the Fe/W–CeO2–P catalyst has the highest NO conversion rate in the temperature range of 100–325 °C among the ordinary amorphous, nanorods, and nanocubes Fe/W–CeO2 catalysts

Use of the Thyromental Height Test for Prediction of Difficult Laryngoscopy: A Systematic Review and Meta-Analysis

The thyromental height test (TMHT) has been proposed as a novel single clinical test for predicting difficult laryngoscopy (DL), though consequent studies have put forward various estimates when verifying its reliability. This systematic review and meta-analysis aimed to provide a comprehensive evaluation of the predictive value of TMHT for DL. A computerized search of CNKI, CQVIP, EBSCO, PubMed, SinoMed, and Wanfang Data was conducted on 1 June 2022. Prospective cohort studies reporting diagnostic properties of TMHT in relation to Cormack and Lehane grading in patients aged more than 16 years, either sex, scheduled for surgery under general anesthesia, requiring tracheal intubation with direct laryngoscopy were included in this analysis. Data was extracted or calculated, and meta-analysis was done by the Stata MIDAS module. A total of 23 studies with 5896 patients were included in this analysis. Summary estimates of all included studies are as follows: sensitivity 74% (95% CI, 68–79%); specificity 88% (95% CI, 81–92%); diagnostic odd ratio, 20 (95% CI, 10–40); positive likelihood ratio, 5.9 (95% CI, 3.6–9.6); and negative likelihood ratio, 0.30 (95% CI, 0.23–0.39). Summary sensitivity and specificity for studies with a prespecified threshold were 82% (95% CI, 71–89%) and 94% (95% CI, 87–98%), respectively. The estimated area under curve (AUC) was 85% (95% CI, 81–88%). There was no significant threshold effect but significant heterogeneity in both sensitivity and specificity. Heterogeneity in sensitivity became insignificant after removing two outliers of sensitivity analysis. It is concluded that THMT has an overall optimal predictive value for DL in adult patients with diverse ethnicity and various risk factors, displaying better predictive values in a large patient population comparing to other recent reported bedside assessments and a previous meta-analysis. As significant heterogeneity brought by un-standardized application of external laryngeal manipulations in the included studies may have biased the results of this meta-analysis, the actual predictive value of TMHT for DL still awaits further studies with good designs and large sample sizes for better determination

GRU-based multi-scenario gait authentication for smartphones

At present, most of the gait-based smartphone authentication researches focus on a single controlled scenario without considering the impact of multi-scenario changes on the authentication accuracy.The movement direction of the smartphone and the user changes in different scenarios, and the user’s gait data collected by the orientation-sensitive sensor will be biased accordingly.Therefore, it has become an urgent problem to provide a multi-scenario high-accuracy gait authentication method for smartphones.In addition, the selection of the model training algorithm determines the accuracy and efficiency of gait authentication.The current popular authentication model based on long short-term memory (LSTM) network can achieve high authentication accuracy, but it has many training parameters, large memory footprint, and the training efficiency needs to be improved.In order to solve the above problems a multi-scenario gait authentication scheme for smartphones based on Gate Recurrent Unit (GRU) was proposed.The gait signals were preliminarily denoised by wavelet transform, and the looped gait signals were segmented by an adaptive gait cycle segmentation algorithm.In order to meet the authentication requirements of multi-scenario, the coordinate system transformation method was used to perform direction-independent processing on the gait signals, so as to eliminate the influence of the orientation of the smartphone and the movement of the user on the authentication result.Besides, in order to achieve high-accuracy authentication and efficient model training, GRUs with different architectures and various optimization methods were used to train the gait model.The proposed scheme was experimentally analyzed on publicly available datasets PSR and ZJU-GaitAcc.Compared with the related schemes, the proposed scheme improves the authentication accuracy.Compared with the LSTM-based gait authentication model, the training efficiency of the proposed model is improved by about 20%