A universal interface for plug-and-play assembly of stretchable devices.

Stretchable hybrid devices have enabled high-fidelity implantable1-3 and on-skin4-6 monitoring of physiological signals. These devices typically contain soft modules that match the mechanical requirements in humans7,8 and soft robots9,10, rigid modules containing Si-based microelectronics11,12 and protective encapsulation modules13,14. To make such a system mechanically compliant, the interconnects between the modules need to tolerate stress concentration that may limit their stretching and ultimately cause debonding failure15-17. Here, we report a universal interface that can reliably connect soft, rigid and encapsulation modules together to form robust and highly stretchable devices in a plug-and-play manner. The interface, consisting of interpenetrating polymer and metal nanostructures, connects modules by simply pressing without using pastes. Its formation is depicted by a biphasic network growth model. Soft-soft modules joined by this interface achieved 600% and 180% mechanical and electrical stretchability, respectively. Soft and rigid modules can also be electrically connected using the above interface. Encapsulation on soft modules with this interface is strongly adhesive with an interfacial toughness of 0.24 N mm-1. As a proof of concept, we use this interface to assemble stretchable devices for in vivo neuromodulation and on-skin electromyography, with high signal quality and mechanical resistance. We expect such a plug-and-play interface to simplify and accelerate the development of on-skin and implantable stretchable devices.

Correction: Public Opinion About COVID-19 on a Microblog Platform in China: Topic Modeling and Multidimensional Sentiment Analysis of Social Media.

[This corrects the article DOI: 10.2196/47508.].

Public Opinion About COVID-19 on a Microblog Platform in China: Topic Modeling and Multidimensional Sentiment Analysis of Social Media.

BACKGROUND: The COVID-19 pandemic raised wide concern from all walks of life globally. Social media platforms became an important channel for information dissemination and an effective medium for public sentiment transmission during the COVID-19 pandemic. OBJECTIVE: Mining and analyzing social media text information can not only reflect the changes in public sentiment characteristics during the COVID-19 pandemic but also help the government understand the trends in public opinion and reasonably control public opinion. METHODS: First, this study collected microblog comments related to the COVID-19 pandemic as a data set. Second, sentiment analysis was carried out based on the topic modeling method combining latent Dirichlet allocation (LDA) and Bidirectional Encoder Representations from Transformers (BERT). Finally, a machine learning linear regression (ML-LR) model combined with a sparse matrix was proposed to explore the evolutionary trend in public opinion on social media and verify the high accuracy of the model. RESULTS: The experimental results show that, in different stages, the characteristics of public emotion are different, and the overall trend is from negative to positive. CONCLUSIONS: The proposed method can effectively reflect the characteristics of the different times and space of public opinion. The results provide theoretical support and practical reference in response to public health and safety events.

Why and how do consumers use dietary supplements? A systematic review and thematic analysis.

Using the input-process-output (IPO) model as an organizing framework, this paper provides an overview of the literature on multiple dimensions of dietary supplement (DS) consumption. Based on a systematic review of 174 studies from different disciplines over two decades, we pinpointed the key topics that have been examined in this growing body of literature and identified the major themes within DS consumption. Moreover, we integrated the major themes in inputs, processes, and outputs to develop a comprehensive understanding of individuals' DS consumption behaviors, motivations, and social mechanisms underlying such behaviors. This research has implications for health consumption and promotion research. We identified DS consumption as a social-cultural process in which individuals practice lifelong self-learning and socialization activities through which lay health knowledge may be developed. Accordingly, their DS use motives may be related to health improvement or not (e.g. identity expressions), which are formed during interactions with various stakeholders in the health marketplace. When confronting the contemporary health promotion culture and self-care paradigm, it is important for researchers to deepen our knowledge of consumers' motives for DS consumption and the underlying social mechanisms to aid consumers' health consumption decisions and guide the multiple stakeholders in the health marketplace.

Dynamic Fluorescent Patterning Based on Visible-Light-Responsive Diselenide Metathesis.

A diselenide bond, as a dynamic covalent bond, is a versatile tool to construct smart interfaces, which can respond to visible light. In this work, we used microcontact printing (µCP) to construct diselenide patterns on quartz substrates. Fluorescent patterns were obtained on the modified surfaces via the visible-light-induced diselenide metathesis reaction, which allowed the patterning process to be fast, dynamically erasable, and compatible with different fluorescent molecules including rhodamine B and boron-dipyrromethene (BODIPY) used in this work. A variety of analytical methods offered comprehensive evidence for the success of the printing of diselenides here. We further printed diselenide and disulfide intersecting stripes on one single quartz substrate layer by layer and introduced rhodamine B and BODIPY to obtain a multicolored pattern simultaneously. By taking advantage of their responsiveness to different wavelengths, the composite pattern of disulfides and diselenides could be erased by two stepwise stages. The fluorescent images of the modified substrate showed a good agreement with the pattern of the poly(dimethylsiloxane) (PDMS) stamp, indicating the methodology with a potential application for information storage.

Fiber-optic multipoint laser-ultrasonic excitation transducer using coreless fibers.

Photoacoustic ultrasound excitation has great potential in structural nondestructive testing and applications for medical treatments as a promising alternative to electrical ultrasound. This study proposes and demonstrates a multipoint optical fiber laser-ultrasonic transducer system, wherein the fiber-optic ultrasonic transducer is fabricated by a coreless fiber segment's fusion with single-mode fibers at each end. Simulation and experiment results show that the transducer coupling ratio is dependent on the coreless fiber's length. The structure of such an ultrasonic transducer is easily manufactured. Thus, the structures of these optical fiber ultrasonic transducers with different coupling ratios are connected in the order of small to large coupling ratios. In this manner, multipoint ultrasonic excitation with equal intensities at each excitation point can be obtained using this simple and low-cost method. Using laser guidance through the optical fiber to generate ultrasound can efficiently solve some shortcomings of traditional ultrasonic transducers, such as large volume, small bandwidth, and electromagnetic interference. Moreover, this type of fiber-optic ultrasound transducer has higher mechanical strength than other fiber-optic ultrasound transducers and is expected to be useful in structural health-monitoring of buildings.

Wavelength-Controlled Dynamic Metathesis: A Light-Driven Exchange Reaction between Disulfide and Diselenide Bonds.

Wavelength-controlled dynamic processes are mostly based on light-triggered isomerization or the cleavage/formation of molecular connections. Control over dynamic metathesis reactions by different light wavelengths, which would be useful in controllable dynamic chemistry, has rarely been studied. Taking advantage of the different bond energies of disulfide and diselenide bonds, we have developed a wavelength-driven exchange reaction between disulfides and diselenides, which underwent metathesis under UV light to produce Se-S bonds. When irradiated with visible light, the Se-S bonds were reversed back to those of the original reactants. The conversion of the exchange depends on the wavelength of the incident light. This light-driven metathesis chemistry was also applied to tune the mechanical properties of polymer materials. The visible-light-induced reverse reaction was compatible with reductant-catalyzed disulfide/diselenide metathesis, and could be utilized to develop a dissipative system with light as the energy input.

Eight Novel Capsular Polysaccharide Synthesis Gene Loci Identified in Nontypeable Streptococcus suis Isolates.

Streptococcus suis is an important pathogen of pigs and may cause serious disease in humans. Serotyping is one of the important diagnostic tools and is used for the epidemiological study of S. suis. Nontypeable S. suis strains have been reported in many studies; however, the capsular polysaccharide (CPS) synthesis cps loci of nontypeable strains have not been analyzed. In this study, we investigated the genetic characteristics of cps loci in 78 nontypeable strains isolated from healthy pigs. Eight novel cps loci (NCLs) were found, and all of them were located between the orfZ-orfX region and the glf gene. All NCLs possess the wzy and wzx genes, strongly suggesting that the CPSs of these NCLs were synthesized using the Wzx/Wzy-dependent pathway. The cps genes found in the 78 isolates were assigned to 96 homology groups (HGs), 55 of which were NCL specific. The encapsulation of the 78 isolates was also examined using transmission electron microscopy. Fifty-three isolates were found to have a capsule, and these were of varied thicknesses. Our data enhance our understanding of the cps gene cluster diversity of nontypeable S. suis strains and provide insight into the evolution of the S. suis capsular genes.

Population analysis of Streptococcus suis isolates from slaughtered swine by use of minimum core genome sequence typing.

Streptococcus suis, an important zoonotic pathogen, is a highly diverse species with only a subset of strains that cause disease in humans. Our previous study proposed a minimum core genome (MCG) sequence typing method and defined seven MCG groups, with MCG group 1 as the prevalent group causing human infections. In this study, we identified a set of 10 single nucleotide polymorphisms (SNPs) distributed in six genes that were used to identify the seven MCG groups. The 10 SNPs were typed for 179 S. suis isolates collected from slaughtered pigs. The most prevalent groups among the tested isolates were MCG groups 6 and 7. Most of the isolates (147/179) were genotyped as mrp negative, epf negative, sly negative, and CDS2157 positive. The 179 isolates were also typed by multilocus sequence typing (MLST) and divided into 115 sequence types (STs), 111 of which were new. The 6 serotypes (29, 11, 5, 12, 30, and 2) represented 72.3% of the serotyped isolates. Our data show that the typing assay facilitates the application of genome data to the surveillance of S. suis.

Characterization of Shiga toxin-producing Escherichia coli isolated from healthy pigs in China.

BACKGROUND: Shiga toxin-producing Escherichia coli (STEC) is recognized as an important human diarrheal pathogen. Swine plays an important role as a carrier of this pathogen. In this study we determined the prevalence and characteristics of STEC from healthy swine collected between May 2011 and August 2012 from 3 cities/provinces in China. RESULTS: A total of 1003 samples, including 326 fecal, 351 small intestinal contents and 326 colon contents samples, was analyzed. Two hundred and fifty five samples were stx-positive by PCR and 93 STEC isolates were recovered from 62 stx-positive samples. Twelve O serogroups and 19 O:H serotypes including 6 serotypes (O100:H20/[H20], O143:H38/[H38], O87:H10, O172:H30/[H30], O159:H16, O9:H30/[H30]) rarely found in swine and ruminants were identified. All 93 STEC isolates harbored stx2 only, all of which were stx2e subtype including 1 isolate being a new variant of stx2e. 53.76%, 15.05% and 2.15% STEC isolates carried astA, hlyA and ehxA respectively. Four STEC isolates harbored the high-pathogenicity island. Of the 15 adherence-associated genes tested, 13 (eae, efa1, iha, lpfAO113, lpfAO157/OI-154, lpfAO157/OI-141, toxB, saa, F4, F5, F6, F17 or F41) were all absent while 2 (paa and F18) were present in 7 and 4 STEC isolates respectively. The majority of the isolates were resistant to tetracycline (79.57%), nalidixic acid (78.49%), trimethoprim-sulfamethoxazole (73.12%) and kanamycin (55.91%). The STEC isolates were divided into 63 pulsed-field gel electrophoresis patterns and 21 sequence types (STs). Isolates of the same STs generally showed the same or similar drug resistance patterns. A higher proportion of STEC isolates from Chongqing showed multidrug resistance with one ST (ST3628) resistant to 14 antimicrobials. CONCLUSIONS: Our results indicate that swine is a significant reservoir of STEC strains in China. Based on comparison by serotypes and sequence types with human strains and presence of virulence genes, the swine STEC may have a low potential to cause human disease.

Dynamic diselenide bonds: exchange reaction induced by visible light without catalysis.

Dynamic covalent bonds are extensively employed in dynamic combinatorial chemistry. The metathesis reaction of disulfide bonds is widely used, but requires catalysis or irradiation with ultraviolet (UV) light. It was found that diselenide bonds are dynamic covalent bonds and undergo dynamic exchange reactions under mild conditions for diselenide metathesis. This reaction is induced by irradiation with visible light and stops in the dark. The exchange is assumed to proceed through a radical mechanism, and experiments with 2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO) support this assumption. Furthermore, the reaction can be conducted in different solvents, including protic solvents. Diselenide metathesis can also be used to synthesize diselenide-containing asymmetric block copolymers. This work thus entails the use of diselenide bonds as dynamic covalent bonds, the development of a dynamic exchange reaction under mild conditions, and an extension of selenium-related dynamic chemistry.

Mitigating the Overheat of Stretchable Electronic Devices Via High-Enthalpy Thermal Dissipation of Hydrogel Encapsulation.

The practical application of flexible and stretchable electronics is significantly influenced by their thermal and chemical stability. Elastomer substrates and encapsulation, due to their soft polymer chains and high surface-area-to-volume ratio, are particularly susceptible to high temperatures and flame. Excessive heat poses a severe threat of damage and decomposition to these elastomers. By leveraging water as a high enthalpy dissipating agent, here, a hydrogel encapsulation strategy is proposed to enhance the flame retardancy and thermal stability of stretchable electronics. The hydrogel-based encapsulation provides thermal protection against flames for more than 10 s through the evaporation of water. Further, the stretchability and functions automatically recover by absorbing air moisture. The incorporation of hydrogel encapsulation enables stretchable electronics to maintain their functions and perform complex tasks, such as fire saving in soft robotics and integrated electronics sensing. With high enthalpy heat dissipation, encapsulated soft electronic devices are effectively shielded and retain their full functionality. This strategy offers a universal method for flame retardant encapsulation of stretchable electronic devices.

An Antidehydration Hydrogel Based on Zwitterionic Oligomers for Bioelectronic Interfacing.

Hydrogels are ideal interfacing materials for on-skin healthcare devices, yet their susceptibility to dehydration hinders their practical use. While incorporating hygroscopic metal salts can prevent dehydration and maintain ionic conductivity, concerns arise regarding metal toxicity due to the passage of small ions through the skin barrier. Herein, an antidehydration hydrogel enabled by the incorporation of zwitterionic oligomers into its network is reported. This hydrogel exhibits exceptional water retention properties, maintaining ≈88% of its weight at 40% relative humidity, 25 °C for 50 days and about 84% after being heated at 50 °C for 3 h. Crucially, the molecular weight design of the embedded oligomers prevents their penetration into the epidermis, as evidenced by experimental and molecular simulation results. The hydrogel allows stable signal acquisition in electrophysiological monitoring of humans and plants under low-humidity conditions. This research provides a promising strategy for the development of epidermis-safe and biocompatible antidehydration hydrogel interfaces for on-skin devices.

Minimum core genome sequence typing of bacterial pathogens: a unified approach for clinical and public health microbiology.

Bacterial pathogens impose a heavy health burden worldwide. In the new era of high-throughput sequencing and online bioinformatics, real-time genome typing of infecting agents, and in particular those with potential severe clinical outcomes, holds promise for guiding clinical care to limit the detrimental effects of infections and to prevent potential local or global outbreaks. Here, we sequenced and compared 85 isolates of Streptococcus suis, a zoonotic human and swine pathogen, wherein we analyzed 32 recognized serotypes and 75 sequence types representing the diversity of the species and the human clinical isolates with high public health significance. We found that 1,077 of the 2,469 genes are shared by all isolates. Excluding 201 common but mobile genes, 876 genes were defined as the minimum core genome (MCG) of the species. Of 190,894 single-nucleotide polymorphisms (SNPs) identified, 58,501 were located in the MCG genes and were referred to as MCG SNPs. A population structure analysis of these MCG SNPs classified the 85 isolates into seven MCG groups, of which MCG group 1 includes all isolates from human infections and outbreaks. Our MCG typing system for S. suis provided a clear separation of groups containing human-associated isolates from those containing animal-associated isolates. It also separated the group containing outbreak isolates, including those causing life-threatening streptococcal toxic shock-like syndrome, from sporadic or less severe meningitis or bacteremia-only isolates. The typing system facilitates the application of genome data to the fields of clinical medicine and epidemiology and to the surveillance of S. suis. The MCG groups may also be used as the taxonomical units of S. suis to define bacterial subpopulations with the potential to cause severe clinical infections and large-scale outbreaks.

Enhancing the interfacial binding strength between modular stretchable electronic components.

Stretchable electronics are emerging for personalized and decentralized clinics, wearable devices and human-machine interactions. Nowadays, separated stretchable functional parts have been well developed and are approaching practical usage. However, the production of whole stretchable devices with full functions still faces a huge challenge: the integration of different components, which was hindered by the mechanical mismatch and stress/strain concentration at the connection interfaces. To avoid connection failure in stretchable devices, a new research focus is to improve the interfacial binding strength between different components. In this review, recent developments to enhance interfacial strength in wearable/implantable electronics are introduced and catalogued into three major strategies: (i) covalent bonding between different device parts, (ii) molecular interpenetration or mechanical interlocking at the interfaces and (iii) covalent connection between the human body and devices. Besides reviewing current methods, we also discuss the existing challenges and possible improvements for stretchable devices from the aspect of interfacial connections.

Enhancing Prosthetic Control through High-Fidelity Myoelectric Mapping with Molecular Anchoring Technology.

Myoelectric control utilizes electrical signals generated from the voluntary contraction of remaining muscles in an amputee's stump to operate a prosthesis. Precise and agile control requires low-level myoelectric signals (below 10% of maximum voluntary contraction, MVC) from weak muscle contractions such as phantom finger or wrist movements, but imbalanced calcium concentration in atrophic skin can distort the signals. This is due to poor ionic-electronic coupling between skin and electrode, which often causes excessive muscle contraction, fatigue, and discomfort during delicate tasks. To overcome this challenge, a new strategy called molecular anchoring is developed to drive hydrophobic molecular effectively interact with and embed into stratum corneum for high coupling regions between ionic fluxes and electronic currents. The use of hydrophobic poly(N-vinyl caprolactam) gel has resulted in an interface impedance of 20 kΩ, which is 1/100 of a commercial acrylic-based electrode, allowing the detection of ultralow myoelectric signals (≈1.5% MVC) that approach human limits. With this molecular anchoring technology, amputees operate a prosthesis with greater dexterity, as phantom finger and wrist movements are predicted with 97.6% accuracy. This strategy provides the potential for a comfortable human-machine interface when amputees accomplish day-to-day tasks through precise and dexterous myoelectric control.

Influential Nodes Identification in the Air Pollution Spatial Correlation Weighted Networks and Collaborative Governance: Taking China's Three Urban Agglomerations as Examples.

Nowadays, driven by green and low-carbon development, accelerating the innovation of joint prevention and control system of air pollution and collaborating to reduce greenhouse gases has become the focus of China's air pollution prevention and control during the "Fourteenth Five-Year Plan" period (2021-2025). In this paper, the air quality index (AQI) data of 48 cities in three major urban agglomerations of Beijing-Tianjin-Hebei, Pearl River Delta and Yangtze River Delta, were selected as samples. Firstly, the air pollution spatial correlation weighted networks of three urban agglomerations are constructed and the overall characteristics of the networks are analyzed. Secondly, an influential nodes identification method, local-and-global-influence for weighted network (W_LGI), is proposed to identify the influential cities in relatively central positions in the networks. Then, the study area is further focused to include influential cities. This paper builds the air pollution spatial correlation weighted network within an influential city to excavate influential nodes in the city network. It is found that these influential nodes are most closely associated with the other nodes in terms of spatial pollution, and have a certain ability to transmit pollutants to the surrounding nodes. Finally, this paper puts forward policy suggestions for the prevention and control of air pollution from the perspective of the spatial linkage of air pollution. These will improve the efficiency and effectiveness of air pollution prevention and control, jointly achieve green development and help achieve the "carbon peak and carbon neutrality" goals.

Research on Determining the Critical Influencing Factors of Carbon Emission Integrating GRA with an Improved STIRPAT Model: Taking the Yangtze River Delta as an Example.

Driven by China's peak carbon emissions and carbon neutrality goals, each region should choose a suitable local implementation path according to local conditions, so it is of great significance to mine and analyze the critical influencing factors of regional carbon emissions. Therefore, this paper integrates grey relation analysis (GRA) and an improved STIRPAT model and selects the Yangtze River Delta region of China as the research object to analyze the factors affecting carbon emissions in four provinces in the region. Firstly, it uses the IPCC method to calculate the energy carbon emissions of each province. Secondly, according to the existing research, the relevant influencing factors of carbon emissions are sorted and summarized as candidate sets and this paper uses GRA to calculate the correlation degree of the above candidate sets. On this basis, this paper combines with the characteristics of the improved STIRPAT model to determine the index selection criteria and filter out the critical factors of each province. Thirdly, an improved STIRPAT model is constructed for each province to explore the influence of critical factors and analyze the influencing factors of carbon emissions in detail. The empirical results show that during the period from 2005 to 2019, the carbon emissions of the four provinces in the Yangtze River Delta are significantly different in structure and trend. At the same time, the critical influencing factors of each province are different and the influence of the same factor on different regions is significantly different. Finally, the policy suggestions for the provinces to achieve their peak carbon emissions and carbon neutrality goals are precisely tailored to the different carbon emission influencing factors.

Water-Enhanced and Remote Self-Healing Elastomers in Various Harsh Environments.

The development of underwater remote stimulus-responsive self-healing polymer materials for applications in inaccessible and urgent situations is very challenging because water can readily disturb traditional noncovalent bonds and absorb heat, UV light, IR light, and electromagnetic wave energy at the wave band of micrometers and millimeters. Herein, visible-light-responsive diselenide bonds are employed as the healing moieties to produce a water-enhanced and remote self-healing elastomer triggered by a blue laser, which possesses excellent underwater transmission capability. During healing, the strain at break reaches ∼200% in 5 min and its toughness almost fully recovers within 1 h, which is estimated to be the fastest reported to date for healing silicone elastomers with a healing efficiency above 90%. The remote underwater pipeline sealing is instantly accomplished with the diselenide-containing elastomers by a blue laser 3 m away, thereby providing a direction for future emergent healing applications.

Self-Reporting Joule Heating Modulated Stiffness of Polymeric Nanocomposites for Shape Reconfiguration.

Shape reconfigurable devices, e.g., foldable phones, have emerged with the development of flexible electronics. But their rigid frames limit the feasible shapes for the devices. To achieve freely changeable shapes yet keep the rigidity of devices for user-friendly operations, stiffness-tunable materials are desired, especially under electrical control. However, current such systems are multilayer with at least a heater layer and a structural layer, leading to complex fabrication, high cost, and loss of reprocessability. Herein, we fabricate covalent adaptable networks-carbon nanotubes (CAN-CNT) composites to realize Joule heating controlled stiffness. The nanocomposites function as stiffness-tunable matrices, electric heaters, and softening sensors all by themselves. The self-reporting of softening is used to regulate the power control, and the sensing mechanism is investigated by simulating the CNT-polymer chain interactions at the nanoscale during the softening process. The nanocomposites not only have adjustable mechanical and thermodynamic properties but also are easy to fabricate at low cost and exhibit reprocessability and recyclability benefiting from the dynamic exchange reactions of CANs. Shape and stiffness control of flexible display systems are demonstrated with the nanocomposites as framing material, where freely reconfigurable shapes are realized to achieve convenient operation, wearing, or storage, fully exploiting their flexible potential.