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The acoustic impedance mismatch between water and air limits the acoustic communication through the water–air interface. Here, based on the resonances of bubbles, we propose a metasurface consisting of bubbles sealed with membranes for perfect sound transmission at the water–air interface. We have experimentally achieved sound transmission enhancement of over 20 dB at 380–510 Hz, with the thickness of the metasurface about 1/180 times air wavelength. By flexibly adjusting the immersion depth, the metasurface is able to operate at multiple frequencies. The effects of viscosity and geometry of bubbles are discussed simulatively. The present work is relevant to the practical design of advanced acoustic devices for transmedia communication. [ABSTRACT FROM AUTHOR]

Among the different nanostructures that have been demonstrated as promising materials for various applications, three–dimensional (3D) nanostructures have attracted significant attention as building blocks for constructing high-performance nanodevices because of their unusual mechanical, electrical, thermal, optical, and magnetic properties arising from their novel size effects and abundant active catalytic/reactive sites due to the high specific surface area. Considerable research efforts have been devoted to designing, fabricating, and evaluating 3D nanostructures for applications, including structural composites, electronics, photonics, biomedical engineering, and energy. This review provides an overview of the nanofabrication strategies that have been developed to fabricate 3D functional architectures with exquisite control over their morphology at the nanoscale. The pros and cons of the typical synthetic methods and experimental protocols are reviewed and outlined. Future challenges of fabrication of 3D nanostructured materials are also discussed to further advance current nanoscience and nanotechnology. [ABSTRACT FROM AUTHOR]

Extreme impedance mismatch causes sound insulation at water–air interfaces, limiting numerous cross‐media applications such as ocean‐air wireless acoustic communication. Although quarter‐wave impedance transformers can improve transmission, they are not readily available for acoustics and are restricted by the fixed phase shift at full transmission. Here, this limitation is broken through impedance‐matched hybrid metasurfaces assisted by topology optimization. Sound transmission enhancement and phase modulation across the water–air interface are achieved independently. Compared to the bare water–air interface, it is experimentally observed that the average transmitted amplitude through an impedance‐matched metasurface at the peak frequency is enhanced by ≈25.9 dB, close to the limit of the perfect transmission 30 dB. And nearly 42 dB amplitude enhancement is measured by the hybrid metasurfaces with axial focusing function. Various customized vortex beams are experimentally realized to promote applications in ocean‐air communication. The physical mechanisms of sound transmission enhancement for broadband and wide‐angle incidences are revealed. The proposed concept has potential applications in efficient transmission and free communication across dissimilar media. [ABSTRACT FROM AUTHOR]

Natural silk fiber derived from the Bombyx mori (B. mori) silkworm has long been used as a luxury raw material in textile industry because of its shimmering appearance and durability, and as surgical suture for its high strength and flexibility. Regenerated silk fibroin, as the main protein extracted from the cocoons of the B. mori silkworm, recently has gained considerable attention due to its outstanding properties, including facile processability, superior biocompatibility, controllable biodegradation, and versatile functionalization. Tremendous effort has been made to fabricate silk fibroin into various promising materials with controlled structural and functional characteristics for advanced utilities in a multitude of biomedical applications, flexible optics, electronics devices, and filtration systems. Herein, reverse engineered silk fibroin extraction methods are reviewed, recent advances in extraction techniques are discussed. Fabrication methods of silk fibroin materials in various formats are also addressed in detail; in particular, progress in new fabrication technologies is presented. Attractive applications of silk fibroin-based materials are then summarized and highlighted. The challenges faced by current approaches in production of silk fibroin-based materials and future directions acquired for pushing these favorable materials further toward above mentioned applications are further elaborated. [ABSTRACT FROM AUTHOR]

Copyright of Acta Mechanica Sinica is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Self-accelerating beams have applications in optic and acoustic fields due to their peculiar properties. As a promising artificial two-dimensional metamaterial, a metasurface can be used as the generator of self-accelerating beams. However, restricted by the generalized Snell's law, most research hotspots focus on flat metasurfaces. In this Letter, the generalized Snell's law on an arbitrary curved reflective surface is discussed. Then, the phase profile for the self-accelerating beams generated from the curved reflective surface is derived based on the caustic theory. The metasurface consisting of the tunable spiral path units is constructed, and numerical and experimental validations are performed. The methodology developed in the present letter extends the applications of the self-accelerating beams. [ABSTRACT FROM AUTHOR]

In this paper, a tunable arc-shaped acoustic metasurface (AAM) carpet cloak has been proposed and systematically investigated. The AAM carpet cloak consists of covers, rotors, bolts and nuts. The rotors can be rotated continuously within the covers to form a reconfigurable hook channel mechanism. By setting various rotational angles, we construct two-dimensional (2D) tunable AAM carpet cloaks to achieve excellent stealth performances under different operating conditions. Numerical simulations and experimental results for the 2D carpet cloaks show good agreements. Furthermore, simulated results for three-dimensional (3D) carpet cloaks have demonstrated that tapered objects are successfully escaping from being detected. The tunable hook channel mechanism can be flexibly applied to arbitrarily curved metasurface carpet cloaks, making them closer to practical invisibility acoustic devices. [ABSTRACT FROM AUTHOR]

Objective To study the application value of surface electromyography in children with dysphagia. Methods A total of 20 children with dysphagia were enrolled as the observation group, and 20 healthy children, matched for sex and age, were enrolled as the control group. Surface electromyography was used to record the electromyography integral values of the submental and infrahyoid muscle groups in the resting state and the state after water swallowing. The two groups were compared in terms of the electromyography integral values of the submental and infrahyoid muscle groups in the resting state and the state after swallowing 5 mL water. The observation group was observed in terms of the changes in the electromyography integral values of the submental and infrahyoid muscle groups after 1 month of rehabilitation treatment. A Spearman correlation analysis was used to evaluate the correlation of the degree of dysphagia with the electromyography integral values of the submental and infrahyoid muscle groups in the observation group. Results There was no significant difference between the two groups in the electromyography integral values of the submental and infrahyoid muscle groups in the resting state (P>0.05), while after water swallowing, the observation group had significantly higher electromyography integral values than the control group (P<0.05). The observation group had significant improvements in the clinical symptoms of dysphagia after treatment, with significant reductions in the electromyography integral values of the submental and infrahyoid muscle groups (P<0.05). The severity of dysphagia was positively correlated with the electromyography integral values of the submental and infrahyoid muscle groups (P<0.01). Conclusions Surface electromyography is useful in the diagnosis and therapeutic effect evaluation for dysphagia in children. [ABSTRACT FROM AUTHOR]

Hybrid Metasurfaces for Perfect Transmission and Customized Manipulation of Sound Across Water-Air Interface (Adv. Sci. 19/2023) More details can be found in article number 2207181 by Yan-Feng Wang, Yue-Sheng Wang, and co-workers. B Acoustic Metasurfaces b By utilizing hybrid impedance-matched metasurfaces floating on the water-air interface, sound waves under the water can be perfectly transmitted to the air with arbitrary desired wavefronts, such as acoustic vortex, thereby greatly improving ocean-air communication efficiency. [Extracted from the article]

Potassium perfluorooctane sulfonate (KPFOS) and sodium perfluorooctane sulfonate (NaPFOS) exhibit poor surface activities in aqueous solution at room temperature because of their high Krafft points. In this work, we attempted to increase the solubility of KPFOS and NaPFOS and consequently improve their surface activities at room temperature with sodium p-methylbenzene sulfonate (BS) and urea, which are typical hydrotropes in industrial applications. The effects of BS and urea on the surface tension of the aqueous solutions of KPFOS and NaPFOS were investigated at 25 °C. When the hydrotropes were added, the effectiveness of KPFOS and NaPFOS in surface tension reduction was greatly enhanced and KPFOS showed higher efficiency in surface tension reduction than NaPFOS. On the other hand, BS had much stronger ability than urea to reduce the surface tension of KPFOS and NaPFOS in water. In particular, with the assistance of BS the minimum surface tension of KPFOS approached 19 mN/m at 25 °C. It was worth noting that in the presence of BS, the surface tension of an apparently 'saturated' solution (i.e., with coexisting surfactant solid) continuously decreased with increasing surfactant concentration. This behavior was ascribed to enrichment of branched PFOS isomers in aqueous phase with the assistance of BS, as evidenced by high-resolution F NMR. Hydrotropes were able to recover the inherent character of KPFOS and NaPFOS as highly surface-active fluorinated surfactants by increasing the solubility of branched isomers. This is an easy way to enhance the effectiveness in surface tension reduction at room temperature for fluorinated surfactants with high Krafft points. [ABSTRACT FROM AUTHOR]

Background: Enterovirus (EV)-related hand, foot, and mouth disease/herpangina (HFMD/HA) has been prevalent in Guangdong Province, China, since 2010.Methods: Clinical data for EV-related HFMD/HA inpatients admitted to the Department of Paediatrics of Zhujiang Hospital from 2010 to 2013 were retrospectively reviewed. The corresponding EV serotypes were also determined by reverse transcription-polymerase chain reaction or BLAST analysis of the sequenced partial lengths of the viral protein1/5'-untranslated region.Results: A total of 867 eligible inpatients admitted during 2010-2013 were included in the study. Of these, the serotype of the responsible EV was successfully identified in 824 cases. The incidence of enterovirus 71 (EV71) infection amongst pediatric HFMD/HA inpatients decreased dramatically from 55.5 % in 2010 to 8.1 % in 2013, with a similar decrease recorded for coxsackievirus A16 (CVA16). However, the incidence of non-EV71/CVA16 infection increased from 30.0 % in 2010 to 83.8 % in 2013. We noted that the types of infection caused by different EV serotypes varied: EV71 was responsible for 100 % of the paralysis cases (26/26), 84.6 % of the deaths (11/13), and 84.1 % of cases with severe central nervous system involvement (SCNSI) (74/88); echovirus contributed to 16.4 % of the deaths (2/13) and 4.4 % of the SCNSI cases; and coxsackievirus accounted for only 2.2 % of the SCNSI cases (2/90). The clinical features of HFMD/HA cases varied greatly during the time period examined, with drastic changes in the hospitalization rates (45.1, 63.7, 36.4, and 19.1 % for 2010, 2011, 2012, and 21013, respectively), mortality rates (2.3, 0.9, 2.5, and 0.0 %, respectively), paralysis (5.1, 1.2, 5.4, and 0.0 %, respectively), SCNSI (16.8, 7.1, 12.7, and 2.2 %, respectively), and acute respiratory infection (21.1, 22.0, 45.9, and 59.0 %, respectively).Conclusions: The incidences of infection caused by different EV serotypes, along with the clinical features of HFMD/HA cases, changed drastically in Guangdong Province, China, from 2010 to 2013, with the biggest changes observed in 2013. The changed constituent ratios of the different EV serotypes might therefore be responsible for the differences in the observed clinical features of HFMD/HA during this period. [ABSTRACT FROM AUTHOR]

Background: A series of complications caused by enteroviruses, including meningitis, encephalitis, acute flaccid paralysis, acute cardiopulmonary failure, respiratory infection, and myocardial injury have been reported in hand, foot and mouth disease/herpangina (HFMD/HA). However, the complication of diarrhoea caused by enteroviruses has been neglected, and a summary of its clinical features and impact on HFMD/HA is unavailable.Methods: We included inpatients with HFMD/HA admitted to the Paediatric Department of Zhujiang Hospital during 2009-2012. We summarised and compared clinical data for cases with and without diarrhoea, and determined enterovirus serotypes by reverse transcriptase polymerase chain reaction and genotyping based on a partial-length fragment of viral protein 1 or the 5'-untranslated region.Results: There were 804 inpatients with HFMD/HA and 28 (3.5%) presented with diarrhoea. Gastrointestinal symptoms were mild in most cases of diarrhoea (82.1%), with high prevalence of no dehydration (82.1%), short duration of diarrhoea (78.6%) and watery stools (75.0%). The prevalence of multi-organ dysfunction syndrome (10.7 vs 0.40%) (p = 0.001), hepatic injury (14.3 vs 3.4%) (p = 0.019), myocardial injury (21.4 vs 6.1%) (p = 0.002) and convulsion (21.4 vs 7.2%) (p = 0.016) was significantly higher in the diarrhoea than no diarrhoea group. There was no significant difference between the two groups regarding prevalence of death, altered consciousness, paralysis, central nervous system involvement, or acute respiratory infection.Conclusions: Most patients with diarrhoea caused by enteroviruses circulating in Guangdong Province in 2009-2012 had mild or moderate gastrointestinal symptoms. Although enterovirus-related diarrhoea caused additional multi-organ dysfunction syndrome, hepatic injury and myocardial injury in children with HFMD/HA, timely intervention efficiently reduced disease severity and improved outcome. [ABSTRACT FROM AUTHOR]

Abstract: Lamadian Oilfield has entered a high water-cut stage after long-term water flooding, and injected water circulates in high-permeability channels. Constant-rate and constant-pressure mercury injections were used to study the change in the physical properties of the reservoir during development by water flooding and that in the features of the pore structure of the reservoir before and after long-term water flush. The constant-rate mercury injection analysis shows that the throat radii of main infiltration paths are enlarged and the pore radius distribution remains constant after long-term water flooding, suggesting that the infiltrating features are controlled mainly by throats instead of pores. The constant-pressure mercury injection analysis shows that water flooding enlarges the pore-throat radius median and maximum radius, increases large throats, and the corresponding pore-throat distribution frequency and permeability. Both methods reveal that pore throats are enlarged after long-term water flooding and large pore throats are the main path of fluid infiltration. [Copyright &y& Elsevier]