bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of noise-induced permanent threshold shift and age-related threshold shift
Authors: Mills John H. , Boettcher Flint A. , Dubno Judy R.
Published: July 2002

Current medical-legal practices as well as an international standard (ISO 1999) assume the permanent threshold shifts produced by exposure to noise add (in dB) to the threshold shifts caused by increased chronological age (presbyacusis). This assumption, known as the additivity rule, was tested in an animal model. Mongolian gerbils, born and raised in a quiet vivarium, were exposed at age 18 months to a 3.5-kHz pure tone for 1 h at 113 dB SPL. At 6-weeks post-exposure, permanent threshold shifts in the exposed ear were approximately 20 dB in the 4- to 8-kHz region. Thresholds in the nonexposed, control ear were unaffected by the exposure. Animals were then allowed to age in the quiet vivarium until age 36 months and then were retested. Thus in a given animal, aging-only effects were assessed in one ear (internal control) and noise-plus-aging effects were assessed in the other (test) ear. A second control was mean age-related threshold shift measured in 48 gerbils who were born and raised in the quiet vivarium. This group is referred to as a non-noise-exposed population (population control). Using the additivity rule, predictions with either the internal or population control significantly overestimated noise-plus-aging effects. Use of the ISO 1999 compression factor reduced the overestimations by 0–5 dB. The intensity rule produced the most accurate predictions. These results suggest that the interaction of noise-induced permanent threshold shift and age-related threshold shift is not straightforward and that current medical-legal methods using the additivity rule overestimate the contribution of “noise effects.”
The perfectly matched layer for acoustic waves in absorptive media
Authors: Liu Qing-Huo , Tao Jianping
Published: July 2002

The perfectly matched layer (PML) was first introduced by Berenger as a material absorbing boundary condition (ABC) for electromagnetic waves. It was first proven by Chew and Liu that a fictitious elastic PML half-space also exists in solids, which completely absorbs elastic waves, in spite of the coupling between compressional and shear waves. The PML absorbing boundary condition provides much higher absorption than other previous ABCs in finite-difference methods. In this work, a method is presented to extend the perfectly matched layer to simulating acoustic wave propagation in absorptive media. This nonphysical material is used at the computational edge of a finite-difference time-domain (FDTD) algorithm as an ABC to truncate unbounded media. Two aspects of the acoustic PML are distinct: (a) For a perfectly matched layer in an intrinsically absorptive medium, an additional term involving the time-integrated pressure field has to be introduced to account for the coupling between the loss from the PML and the normal absorptive loss; (b) In contrast to the full elastodynamic problem, the acoustic PML requires a splitting only on the pressure field, but not on the particle velocity field. The FDTD algorithm is validated by analytical solutions and other numerical results for two- and three-dimensional problems. Unlike the previous ABCs, the PML ABC effectively absorbs outgoing waves at the computational edge even when a dipping interface intersects the outer boundary.
Elasto-acoustics of a two-dimensional thin strip by a hybrid method
Authors: El-Raheb Michael
Published: July 2002

Elastic response of a two-dimensional thin strip coupled to an acoustic fluid is treated. Frequency response of the strip is expressed using transfer matrices of strip segments, and acoustic pressure of the fluid is expressed using a constant source density applied over each segment. Acoustic pressure loading the strip and continuity of elastic and acoustic velocities at midpoints of segments serve to couple the elastic and acoustic fields. Transmission loss (TL) of a baffled simply supported flat strip excited acoustically by diffuse sound is compared to TL from a modal solution, and TL measured across a rectangular plate having the same thickness and material properties. The unexpected close agreement between TL from the two-dimensional (2-D) strip model and measured TL is explained by relating strip and plate’s analytical solutions of frequency response, and acoustic impedance from a prescribed oscillatory motion.
Experimental study of different approaches for active control of sound transmission through double walls
Authors: Bao C. , Pan J.
Published: July 2002

Recently, active noise control technology has been used to increase the sound transmission loss of double-wall structures. Several approaches have been put forward and explored individually. However, no comparative study on those approaches has been conducted to show which approach is more effective for given circumstances. In this paper, three different approaches for controlling sound transmission through double-panel partitions into a room, i.e., applying acoustic control sources in the air gap between the two panels (cavity control), applying vibration control sources on the radiating panel (panel control), and applying acoustic control sources in the receiving room (room control), are studied and compared to each other experimentally. The mechanisms involved in each approach are illustrated and the conditions for effective noise attenuation are examined. The results show that the modal overlap of each subsystem (the cavity, the radiating panel, and the room) and the control mechanisms involved are the two most important factors that determine the effectiveness of each corresponding approach.
Three-dimensional wave-envelope elements of variable order for acoustic radiation and scattering. Part I. Formulation in the frequency domain
Authors: Astley R. J. , Macaulay G. J. , Coyette J-P. , Cremers L.
Published: July 2002

Mapped wave-envelope elements of variable radial order are presented for the computation of time-harmonic, unbounded, three-dimensional acoustical fields. Their application to transient problems is described in a companion article (Part II). Accuracy is assessed by a comparison of computed and analytic solutions for multi-pole fields generated by a vibrating sphere. Solutions are also presented for plane wave scattering. Elements of radial order m+l are shown to be capable of modeling multi-pole components of order m, although the provision of adequate transverse resolution is shown to be a stringent requirement, particularly at high frequencies. Ill-conditioning of the coefficient matrix limits the practical implementation of the method to elements of radial order eleven or less. The utility of the method for more general geometries is demonstrated by the presentation of computed solutions for the sound field generated by the vibration of a cylindrical piston in a plane baffle and of an idealised engine casing under anechoic conditions. The computed results are shown to be in close agreement with the analytic solution in the case of the cylindrical piston, and with a boundary element solution in the case of the engine casing.
Energy fields of partially coherent sources
Authors: Li Jing-Fang , Pascal Jean-Claude , Carles Claude
Published: July 2002

Random acoustic fields and their energetic quantities (acoustic active and reactive intensities, potential and kinetic energy densities) are described in terms of the mutual coherences between sources. Conditions to correctly construct the coherence matrix of sources in a multivariate random process are given. It is shown that the description of a sound field using the coherence matrix of source is equivalent to the superposition of a number of independent coherent fields, which do not correspond to the original localized sources. A method based on processing the principal components of the coherence matrix of sources is given to reduce the number of necessary fields. The coherence function between acoustic pressure and particle velocity and the curl of active intensity are proposed as two indicators for estimating the degree of coherence and the polarization of acoustic fields. These indicators are analyzed theoretically and experimentally. The description of the structure of partially coherent fields is generalized by the definition of the field matrix whose rank is an indicator of the local complexity of an acoustic field.
Unimorph and bimorph actuators
Authors: Yoshikawa Shoko , Saarmaa Erik , Kottenstette Nicholas , Jacques Robert
Published: July 2002

Although piezoelectric ceramic unimorph and bimorph actuators have been around for several decades, detailed scientific understanding and design limitations have not yet been clarified. This study compares unimorph and bimorph actuators and the effects of thermally induced stress on the ceramics. The experimental results and analytical models show that there are optimum thickness and modulus ratios of piezoelectric and non-piezoelectric (substrate) layers for each application, depending on the need for either free stroke or blocked force. Bimorph actuators were found to be significantly more energy efficient than unimorph actuators. The stress effect of the piezoelectric ceramic layer caused by thermal mismatch to the actuator performance was not significant compared with the experimental data and modeled values. However, in soft piezoelectric ceramics, reduction of capacitance due to stress was significant and influenced actuator energy input. Asymmetric thermal stress also caused bowing of thin piezoelectric ceramic samples. The effect of this shape was modeled and compared to the experimental results.
Click train encoding in primary auditory cortex of the awake monkey: Evidence for two mechanisms subserving pitch perception
Authors: Steinschneider Mitchell , Reser David H. , Fishman Yonatan I. , Schroeder Charles E. , Arezzo Joseph C.
Published: July 2002

Multiunit activity (MUA) and current source density (CSD) patterns evoked by click trains are examined in primary auditory cortex (A1) of three awake monkeys. Temporal and spectral features of click trains are differentially encoded in A1. Encoding of temporal features occurs at rates of 100–200 Hz through phase-locked activity in the MUA and CSD, is independent of pulse polarity pattern, and occurs in high best frequency (BF) regions of A1. The upper limit of ensemble-wide phase-locking is about 400 Hz in the input to A1, as manifested in the cortical middle laminae CSD and MUA of thalamocortical fibers. In contrast, encoding of spectral features occurs in low BF regions, and resolves both the f0 and harmonics of the stimuli through local maxima of activity determined by the tonotopic organization of the recording sites. High-pass filtered click trains decrease spectral encoding in low BF regions without modifying phase-locked responses in high BF regions. These physiological responses parallel features of human pitch perception for click trains, and support the existence of two distinct physiological mechanisms involved in pitch perception: the first using resolved harmonic components and the second utilizing unresolved harmonics that is based on encoding stimulus waveform periodicity.
Application of pulse compression techniques to broadband acoustic scattering by live individual zooplankton
Authors: Chu Dezhang , Stanton Timothy K.
Published: July 2002

Distinct frequency dependencies of the acoustic backscattering by zooplankton of different anatomical groups have been observed in our previous studies [, ICES J. Mar. Sci. 49, 97–106 (1992); Stanton et al., ICES J. Mar. Sci. 51, 505–512 (1994)]. Based mainly on the spectral information, scattering models have been proposed to describe the backscattering mechanisms of different zooplankton groups [, J. Acoust. Soc. Am. 103, 236–253 (1998b)]. In this paper, an in-depth study of pulse compression (PC) techniques is presented to characterize the temporal, spectral, and statistical signatures of the acoustic backscattering by zooplankton of different gross anatomical classes. Data collected from various sources are analyzed and the results are consistent with our acoustic models. From compressed pulse (CP) outputs for all three different zooplankton groups, two major arrivals from different parts of the animal body can be identified: a primary and a secondary arrival. (1) Shrimplike animals (Euphausiids and decapod shrimp; near broadside incidence only): the primary one is from the front interface (interface closest to the transducer) of the animal and the secondary arrival is from the back interface; (2) gas-bearing animals (Siphonophores): the primary arrival is from the gas inclusion and the secondary arrival is from the body tissue (“local acoustic center of mass”); and (3) elastic shelled animals (Gastropods): the primary one is from the front interface and the secondary arrival corresponds to the subsonic Lamb wave that circumnavigates the surface of the shell. Statistical analysis of these arrivals is used to successfully infer the size of the individual animals. In conjunction with different aspects of PC techniques explored in this paper, a concept of partial wave target strength (PWTS) is introduced to describe scattering by the different CP highlights. Furthermore, temporal gating of the CP output allows rejection of unwanted signals, improves the output signal-to-noise ratio (SNR) of the spectra of selected partial waves of interest, and provides a better understanding of the scattering mechanism of the animals. In addition, it is found that the averaged PWTS can be used to obtain a more quantitative scattering characterization for certain animals such as siphonophores.
Nonlinear Stoneley and Scholte waves
Authors: Meegan G. D. , Hamilton M. F. , Il’inskii Yu. A. , Zabolotskaya E. A.
Published: July 2002

Spectral evolution equations are derived for plane, progressive, finite-amplitude Stoneley and Scholte waves that propagate along plane interfaces formed by two semi-infinite, isotropic media in contact. The evolution equations have mathematical forms identical to those obtained previously for Rayleigh waves [E. A. Zabolotskaya, J. Acoust. Soc. Am. 91, 2569–2575 (1992)], and they are expressed explicitly in terms of the second- and third-order elastic constants of the media. Calculations were performed to simulate nonlinear surface wave propagation in several pairs of real media. Harmonic generation and shock formation associated with the Stoneley and Scholte modes are compared with the corresponding processes in Rayleigh waves. Waveform distortion is shown to be very similar for the three types of surface waves when the propagation distance is normalized by an appropriate shock formation distance.
Elimination of branch cuts from the normal-mode solution using gradient half spaces
Authors: Westwood Evan K. , Koch Robert A.
Published: July 2002

A method for eliminating the branch cuts and branch line integrals from the normal-mode solution to the range-invariant acoustic wave equation has been developed and implemented. In the usual normal-mode formulation, evaluation of the vertical wave number in the ocean waveguide’s lower half space involves a square root operation and gives rise to a branch point at the critical angle. When the Pekeris cut is chosen, energy steeper than the critical angle is represented by leaky modes, and lateral-wave energy near the critical angle is represented by the branch line integral. When a mode lies near the branch cut, the branch line integral can be significant at all ranges. Branch line integrals are cumbersome to compute, and, for range-dependent problems, cannot be included in adiabatic and coupled-mode algorithms. By inserting small attenuation and sound-speed gradients in the lower half space, the plane-wave solution is replaced by an Airy function solution, the branch point is eliminated, the Pekeris branch cut is replaced by a series of modes, and the leaky modes become bounded at infinite depth. Implementation of and example calculations using this approach using the normal-mode model ORCA are given.
Frequency dependence of ultrasonic backscatter from human trabecular bone: Theory and experiment
Authors: Wear Keith A.
Published: July 2002

A model describing the frequency dependence of backscatter coefficient from trabecular bone is presented. Scattering is assumed to originate from the surfaces of trabeculae, which are modeled as long thin cylinders with radii small compared with the ultrasonic wavelength. Experimental ultrasonic measurements at 500 kHz, 1 MHz, and 2.25 MHz from a wire target and from trabecular bone samples from human calcaneus in vitro are reported. In both cases, measurements are in good agreement with theory. For mediolateral insonification of calcaneus at low frequencies, including the typical diagnostic range (near 500 kHz), backscatter coefficient is proportional to frequency cubed. At higher frequencies, the frequency response flattens out. The data also suggest that at diagnostic frequencies, multiple scattering effects on the average are relatively small for the samples investigated. Finally, at diagnostic frequencies, the data suggest that absorption is likely to be a larger component of attenuation than scattering.
Adaptive eigenvalue decomposition algorithm for passive acoustic source localization
Authors: Benesty Jacob
Published: July 2002

To find the position of an acoustic source in a room, the relative delay between two (or more) microphone signals for the direct sound must be determined. The generalized cross-correlation method is the most popular technique to do so and is well explained in a landmark paper by Knapp and Carter. In this paper, a new approach is proposed that is based on eigenvalue decomposition. Indeed, the eigenvector corresponding to the minimum eigenvalue of the covariance matrix of the microphone signals contains the impulse responses between the source and the microphone signals (and therefore all the information we need for time delay estimation). In experiments, the proposed algorithm performs well and is very accurate.
Nonlinear Stress Relaxation of Polyisobutylene in Simple Extension
Authors: Taylor Carl R. , Greco Roberto , Kramer Ole , Ferry John D.
Published: July 2002

Relaxation of stress in simple extension of polyisobutylene (viscosity-average molecular weight 2.3×106) has been measured at stretch ratios (λ) up to about 2. Data at 3, 25, and 50°C were reduced to 25°C. At any instant of reduced time, the dependence of stress on λ could be described by the Mooney-Rivlin equation; the coefficients C1 and C2 were obtained from two linear plotting procedures. At short times, C1 decreased rapidly while C2 remained essentially constant. Two to three logarithmic decades of time later, C2 decreased. Thus, the terminal zone of viscoelastic behavior corresponds solely to the C2 contribution. This result confirms measurements by Arai and Niinomi (Kogyo Kagaku Zasshi, 74, 2525 (1971)) on polyisoprene and styrene-butadiene rubber and measurements by Noordermeer and Ferry (J. Polym. Sci., (1976), in press) on 1,2-polybutadiene. Tentative interpretations in terms of motions of entanglements are discussed. Similar measurements on a sample of polyisobutylene which had been heated with vulcanizing ingredients and was very slightly crosslinked gave higher values of C2 but lower values of C1.
Deviation of Velocity Gradient Profiles from the “Gap Loading” and “Surface Loading” Limits in Dynamic Simple Shear Experiments
Authors: Schrag John L.
Published: July 2002

The shear-wave field generated in a linear viscoelastic medium confined between parallel plates (one fixed, the other oscillating sinusoidally in its own plane) has been evaluated and presented in a graphical form convenient for determination of the role of wave propagation effects in dynamic rheological measurements. The transition from closely spaced planes (“gap loading”) to the freely propagating plane wave (“surface loading”) limit is examined; the importance of deviations in magnitude and phase of the gradient profile from the gap loading limit is discussed in terms of high precision dynamic rheological experiments; significant deviations occur for shear wavelength to gap width ratios of 30 or less.
Yield stress in magnetorheological and electrorheological fluids: A comparison between microscopic and macroscopic structural models
Authors: Bossis G. , Lemaire E. , Volkova O. , Clercx H.
Published: July 2002

The yield stress of a magnetorheological suspension is calculated from two different approaches. The first one is based on a mesoscopic description of the structure taking only into account the shape anisotropy of the strained aggregates. The second one is based on a microscopic approach where the interparticle forces, due to the application of the field, are calculated numerically by taking into account the magnetostatics between the particles inside the aggregates. We show that the macroscopic description well applies to suspensions of nonmagnetic particles in a ferrofluid and that a layered structure, consisting of parallel slabs of magnetizable materials should have a yield stress much higher than a structure made of cylindrical aggregates. On the other hand the microscopic approach is appropriated for the description of suspensions of particles of high permeability. In this case, the yield stress is mainly determined by the rupture between pairs of particles and, consequently, it strongly increases with the angle between the line of centers of the pair undergoing the rupture and the field.
Efficient Sodium Storage in Selenium Electrodes Achieved by Selenium Doping and Copper Current Collector Induced Displacement Redox Mechanisms
Authors: Meng Weijia , Dang Zhenzhen , Li Diansen , Jiang Lei , Fang Daining
Published: July 2022

Selenium (Se), with its high specific volume capacity and high electronic and superior kinetics, is considered a promising electrode material with promising applications. However, the solvation and shuttle effects of polyselenides hinder their further application. The selenium/nitrogen‐doped hollow porous carbon spheres (Se/NHPCs) are obtained using the sacrificial template and in situ gas‐phase selenization methods. The Se species are doped into carbon matrixes in an adjustable amount to form Se‐C(N) bonds during this process. Density functional theory calculations show that the Se‐C(N) bond enhances the charge transfer between Na2Se and carbon matrix and binding energy, which improves rate performance and cycling stability. As expected, Se/NHPCs electrode exhibit high reversible capacity (480 mAh g–1 at 0.5 A g–1 after 200 cycles) and rate performance (311 mAh g–1 at 5 A g–1) as the anode for sodium‐ion batteries. A series of ex situ characterization results show that Cu2Se produced by copper current collector induction is effective in the adsorption of polyselenides while enhancing the electrode conductivity. Since the lattice structures of Cu2Se and Na2Se are similar, this displacement reaction that does not involve lattice reconfiguration provides an effective strategy for the preparation of high‐performance and low‐cost electrode materials.
Superionic Bifunctional Polymer Electrolytes for Solid‐State Energy Storage and Conversion
Authors: Wang Rui‐Yang , Jeong Seungwon , Ham Hyeonseong , Kim Jihoon , Lee Hojun , Son Chang Yun , Park Moon Jeong
Published: July 2022

Achieving superionic conductivity from solid‐state polymer electrolytes is an important task in the development of future energy storage and conversion technologies. Herein, a platform for innovative electrolyte technologies based on a bifunctional polymer, poly(3‐hydroxy‐4‐sulfonated styrene) (PS‐3H4S), is presented. By incorporating OH and SO3H functional groups at adjacent positions in the styrene repeating unit, “intra‐monomer” hydrogen bonds are formed to effectively weaken the electrostatic interactions of the SO3− moieties in the polymer matrix with embedded ions, promoting rich structural and dynamic heterogeneity in the PS‐3H4S electrolyte. Upon the incorporation of an ionic liquid, interconnected rod‐like ion channels, which allow the decoupling of ion relaxation from polymer relaxation, are formed in the stiff motif of the polymeric domains passivated by interfacial ionic layers. This results in accelerated proton hopping through the glassy polymer matrix, and proton hopping becomes more pronounced at cryogenic temperatures down to −35 °C. The PS‐3H4S/ionic liquid composite electrolytes exhibit a high ionic conductivity of 10−3 S cm−1 and high storage modulus of ≈100 MPa at 25 °C, and can be successfully applied in soft actuators and lithium‐metal batteries.
Liquid Crystalline Systems from Nature and Interaction of Living Organisms with Liquid Crystals
Authors: Kim Won‐Sik , Im Jun‐Hyung , Kim Hyein , Choi Jin‐Kang , Choi Yena , Kim Young‐Ki
Published: July 2022

Biomaterials, which are substances interacting with biological systems, have been extensively explored to understand living organisms and obtain scientific inspiration (such as biomimetics). However, many aspects of biomaterials have yet to be fully understood. Because liquid crystalline phases are ubiquitously found in biomaterials (e.g., cholesterol, amphiphile, DNA, cellulose, bacteria), therefore, a wide range of research has made attempts to approach unresolved issues with the concept of liquid crystals (LCs). This review presents these studies that address the interactive correlation between biomaterials and LCs. Specifically, intrinsic LC behavior of various biomaterials such as DNA, cellulose nanocrystals, and bacteriaare first introduced. Second, the dynamics of bacteria in LC media are addressed, with focus on how bacteria interact with LCs, and how dynamics of bacteria can be controlled by exploiting the characteristics of LCs. Lastly, how the strong correlation between LCs and biomaterials has been leveraged to design a new class of biosensors with additional functionalities (e.g., self‐regulated drug release) that are not available in previous systems is reviewed. Examples addressed in this review convey the message that the intersection between biomaterials and LCs offers deep insights into fundamental understanding of biomaterials, and provides resources for development of transformative technologies.
Polarized Cu–Bi Site Pairs for Non‐Covalent to Covalent Interaction Tuning toward N2 Photoreduction
Authors: Di Jun , Chen Chao , Wu Yao , Zhao Yunxuan , Zhu Chao , Zhang Yi , Wang Changda , Chen Hailong , Xiong Jun , Xu Manzhang , Xia Jiexiang , Zhou Jiadong , Weng Yuxiang , Song Li , Li Shuzhou , Jiang Wei , Liu Zheng
Published: July 2022

A universal atomic layer confined doping strategy is developed to prepare Bi24O31Br10 materials incorporating isolated Cu atoms. The local polarization can be created along the CuOBi atomic interface, which enables better electron delocalization for effective N2 activation. The optimized Cu‐Bi24O31Br10 atomic layers show 5.3× and 88.2× improved photocatalytic nitrogen fixation activity than Bi24O31Br10 atomic layer and bulk Bi24O31Br10, respectively, with the NH3 generation rate reaching 291.1 µmol g−1 h−1 in pure water. The polarized Cu–Bi site pairs can increase the non‐covalent interaction between the catalyst's surface and N2 molecules, then further weaken the covalent bond order in NN. As a result, the hydrogenation pathways can be altered from the associative distal pathway for Bi24O31Br10 to the alternating pathway for Cu‐Bi24O31Br10. This strategy provides an accessible pathway for designing polarized metal site pairs or tuning the non‐covalent interaction and covalent bond order.
Solvation‐Driven Actuation of Anion‐Exchange Membranes
Authors: Ulbricht Nicco , Boldini Alain , Bae Chulsung , Wallmersperger Thomas , Porfiri Maurizio
Published: July 2022

Ion‐exchange membranes, conventionally utilized in separation processes of electrolyte solutions, are electroactive polymers that display a unique coupling between electrochemistry and mechanics. Previous experimental studies have demonstrated the possibility of actuating cation‐exchange membranes in salt solution through the application of a remote external electric field. The use of anion‐exchange membranes as contactless actuators, however, has never been documented and little is known about the physics of their actuation. Here, it is reported for the first time the possibility of contactless actuating anion‐exchange membranes in salt solutions; such an actuation is mediated by the selection of anions in the external salt solution and the membrane. Actuation is attributed to the physical phenomenon of solvation, the interaction between ions and solvent in solution. Contrary to previous studies with cation‐exchange membranes, the results show that anion‐exchange membranes consistently bend toward the anode. The integration of anion‐exchange and cation‐exchange membranes in composites promises innovative programmable contactless actuators, with applications in underwater robotics and biomedical engineering.
An Engineered Nanocomposite Copper Coating with Enhanced Antibacterial Efficacy
Authors: Nakhaie Davood , Williams Teresa C. , Velapatino Billie , Bryce Elizabeth A. , Charles Marthe K. , Asselin Edouard , Clifford Amanda M.
Published: July 2022

Contaminated surfaces are a major source of nosocomial infection. To reduce microbial bioburden and surface‐based transmission of infectious disease, the use of antibacterial and self‐sanitizing surfaces, such as copper (Cu), is being explored in clinical settings. Cu has long been known to have antimicrobial activity. However, Gram‐positive microorganisms, a class that includes pathogens commonly responsible for hospital‐acquired infection such as Staphylococcus aureus and Clostridioides difficile, are more resilient to its biocidal effect. Inspired by inherently bactericidal nanostructured surfaces found in nature, an improved Cu coating is developed, engineered to contain nanoscale surface features and thus increase its antibacterial activity against a broader range of organisms. In addition, a new method is established for facilitating the rapid and continuous release of biocidal metal ions from the coating, through incorporation of an antibacterial metal salt (ZnCl2) with a lower reduction potential than Cu. Electrophoretic deposition (EPD) is used to fabricate these coatings, which serves as a low‐cost and scalable route for modifying existing conductive surfaces with complex shape. By tuning both the surface morphology and chemistry, a nanocomposite Cu coating is created that decreases the microbial bioburden of Gram‐positive S. aureus by 94% compared to unmodified Cu.
Ferroelectric Single‐Molecule Magnet with Toroidal Magnetic Moments
Authors: Wang Yu‐Xia , Ma Yinina , Wang Jie‐Su , Yang Yue , Guo Yun‐Nan , Zhang Yi‐Quan , Jin Kui‐Juan , Sun Young , Cheng Peng
Published: July 2022

Materials that coexist magnetic and electric properties on the molecular scale in single‐molecule magnets (SMMs) with peculiar quantum behaviors have promise in molecular electronics and spintronics. Nevertheless, such molecular materials are limited in potentials because their magnetic signal cannot be transformed into an electrical signal through magnetoresistance or Hall effects for their high insulativity. The discovery of an entirely new material, ferroelectric SMMs (FE SMMs) is reported. This FE SMM also shows single‐molecule magnetic behaviors, toroidal magnetic moments, and room‐temperature ferroelectricity. The toroidal moment is formed by a vortex distribution of magnetic dipoles in triangular Dy3 clusters. The analysis of ac magnetic susceptibility reveals the coexistence of three distinct magnetic relaxation processes at low temperatures. The ferroelectricity is introduced by incorporating polar alcohol molecules in the structure, which is confirmed by the X‐ray diffraction and optical second harmonic generation (SHG) measurements. Moreover, the dielectric measurements reveal a ferroelectric‐to‐ferroelectric phase transition around 150 K due to the symmetry change from Pc to Pna21. The coexistence of toroidal moment and ferroelectricity along with quantum magnetism in the rare‐earth single‐molecule magnets yields a unique class of multiferroics.
Retracted: Radical Covalent Organic Frameworks Associated with Liquid Na‐K toward Dendrite‐Free Alkali Metal Anodes
Authors: Wang Jianyi , Chen Menghui , Lu Zicong , Chen Zhida , Si Liping
Published: July 2022

Liquid sodium‐potassium (Na‐K) alloy has the characteristics of high abundance, low redox potential, high capacity, and no dendrites, which has become an ideal alternative material for potassium/sodium metal anodes. However, the high surface tension of liquid sodium potassium alloy at room temperature makes it inconvenient in practical use. Here, the Na‐K as reducing agent treats with hydrazone linkages of covalent organic frameworks (COFs) and obtain the carbon‐oxygen radical COFs (COR‐Tf‐DHzDM‐COFs). The preparation method solves the problems that the preparation process of the traditional Na‐K composite anode is complex and has high cost. The structures of the COR‐Tf‐DHzDM‐COFs are characterized by X‐ray diffraction （XRD), fourier transform infrared (FT‐IR), electron paramagnetic resonance (EPR), and solid‐state NMR measurements. It is the first time that carbon‐oxygen radical COFs from bulk COFs are constructed by one‐step method and the operation is flexible, convenient, and high rate of quality, which is suitable for big production and widely used. The cycle stability of the composite Na‐K anode is improved, which provides a new idea for the design of high‐performance liquid metal anode.
Further delineation of GEMIN4 related neurodevelopmental disorder with microcephaly, cataract, and renal abnormalities syndrome
Authors: Altassan Ruqaiah , Qudair Ahmad , Alokaili Riyadh , Alhasan Khalid , Faqeih Eissa A. , Alhashem Amal , Alowain Muhammed , Alsayed Moeanaldeen , Rahbeeni Zuhair , Albadi Lama , Alkuraya Fowzan S. , Anderson Eric N. , Rajan Deepa , Pandey Udai Bhan
Published: July 2022

Pathogenic variants in GEMIN4 have recently been linked to an inherited autosomal recessive neurodevelopmental disorder characterized with microcephaly, cataracts, and renal abnormalities (NEDMCR syndrome). This report provides a retrospective review of 16 patients from 11 unrelated Saudi consanguineous families with GEMIN4 mutations. The cohort comprises 11 new and unpublished clinical details from five previously described patients. Only two missense, homozygous, pathogenic variants were found in all affected patients, suggesting a founder effect. All patients shared global developmental delay with variable ophthalmological, renal, and skeletal manifestations. In addition, we knocked down endogenous Drosophila GEMIN4 in neurons to further investigate the mechanism of the functional defects in affected patients. Our fly model findings demonstrated developmental defects and motor dysfunction suggesting that loss of GEMIN4 function is detrimental in vivo; likely similar to human patients. To date, this study presents the largest cohort of patients affected with GEMIN4 mutations. Considering that identifying GEMIN4 defects in patients presenting with neurodevelopmental delay and congenital cataract will help in early diagnosis, appropriate management and prevention plans that can be made for affected families.
A simulation‐based integrated virtual testbed for dynamic optimization in smart manufacturing systems
Authors: Sun Yuting , Tu Jiachen , Bragin Mikhail , Zhang Liang
Published: July 2022

In a manufacturing system, production control‐related decision‐making activities occur at different levels. At the process level, one of the main control activities is to tune the parameters of individual manufacturing equipment. At the system level, the main activity is to coordinate production resources and to route parts to appropriate workstations based on their processing requirement, priority indices, and control policy. At the factory level, the goal is to plan and schedule the processing of parts at different operations for the entire system in order to optimize certain objectives. Note that the results of such activities at different levels are closely coupled and affect the overall performance of the manufacturing system as a whole. Therefore, it is important to systematically integrate these control and optimization activities into one unified platform to ensure the goal of each individual activity is aligned with the overall performance of the system. In this paper, we develop a simulation‐based virtual testbed that implements dynamic optimization, automatic information exchange, and decision‐making from the process‐level, system‐level, and factory‐level of a manufacturing system into an integrated computation environment. This is demonstrated by connecting a Python‐based numerical computation program, discrete‐event simulation software (Simul8), and an optimization solver (CPLEX) via a third‐party master program. The application of this simulation‐based virtual testbed is illustrated by a case study in a machining shop.
Staged co‐gasification characteristics of pyrolyzed semi‐coke and antibiotic filter residue under oxy‐fuel condition
Authors: Wang Chang'an , Luo Maoyun , Tang Guantao , Jin Liyan , Zhao Lin , Che Defu
Published: July 2022

Pyrolyzed semi‐coke (SC) is a by‐product of coal‐graded utilization, while the clean and efficient utilization of excess powdery pyrolyzed SC has given a huge challenge. The antibiotic filter residue (AFR) is a kind of biomass solid wastes, which also requires proper disposal or resource utilization. Utilizing the fuel complementary characteristics of pyrolyzed SC and AFR, oxy‐fuel gasification co‐processing can not only effectively realize the resource utilization of solid wastes but also achieve significant CO2reduction boosting carbon neutrality. Here, the Aspen Plus software was used to simulate the staged oxy‐fuel co‐gasification characteristics of SC and AFR. The simulation results show that with the increase of the SC proportion in blends from 0% to 100%, the lower heating value is raised from 9.48 to 11.26 MJ·m−3, the gas yield is increased from 1.39 to 2.55 m3·kg−1, and the cold gas efficiency grows by 39.28%. The rise of oxygen volume percentage improves the lower heating value in the produced gas and volume fraction of H2, but the contents of CO and CO2, together with the gas yield and cold gas efficiency, show decreasing trends. Raising gasification temperature within a reasonable range is beneficial for enhancing the gasification performance and improving the syngas quality. The raised oxygen equivalent ratio increases the content of CO2but leads to the decline of CO and H2. For sample AFR, as the oxygen equivalent ratio is varied from 0.6 to 0.8, the volume fraction of CO2increases by 14.19%, while the contents of CO and H2reduce by 5.34% and 8.77%, respectively. The present study offers effective support for the co‐disposal and resource utilization of powdery pyrolyzed SC and AFR.
Synthesis and characterization of ultra‐tough crosslinked polyamide with hybrid polymer networks equipping strong hydrogen bonds
Authors: Chen Yu‐Hao , Chang Yun , Rwei Syang‐Peng
Published: July 2022

In this work, a novel crosslinked polyamide (cPA) system with hybrid polymer networks was developed. The hexamethylenediamine, acrylic acid (AA), and bis(6‐aminohexyl) dodecanediamide (BAHD) were utilized as the main building block in crosslinked polyamide (cPA) system by Michael addition reaction and polycondensation, wherein an amide diamine monomer, BAHD, was utilized as the building provider of hydrogen‐bonding networks. Simultaneously, the internal covalent bond networks were constructed by the Michael addition between AA and diamine, resulting in permanent covalent crosslinks. By adjusting the ratio of BAHD content, a series of copolyamides were successfully synthesized, and the thermal, mechanical, and viscoelastic behavior of cPAs were systematically discussed. Based on these results, the best mechanical properties in our cPAs were found in the composition of BH37, which exhibited microcrystalline behavior and outstanding tensile properties with melting temperature of 55°C, tensile strength above 45 MPa, and elongation at break above 1000%. It demonstrated that the adjusting of reversible hydrogen bonds and permanent covalent crosslinks in hybrid polymer networks could effectively endow the cPAs with excellent flexibility and strength. These studies provide useful information for designing novel cPA materials with controlled thermal and mechanical properties, which suggested the potential for use in advanced application fields.
Experimental study of the hydroquinone (HQ)–hexamethylenetetramine (HMTA) gel system for conformance improvement in extremely high‐temperature reservoirs
Authors: Deng Bo , Liu Wei , Gu Jianwei , Song Yanan , Liu Chao , Ruan Banxi , Chen Bowen
Published: July 2022

An organically crosslinked polymer with hydroquinone (HQ)–hexamethylenetetramine (HMTA) as crosslinker used for profile control was analyzed systematically at extremely high temperatures (over 150°C). The optimal gelation time and gelation performance may be achieved by changing the polymer and crosslinking agent concentrations. The gelation time is decreased and the gelation performance is improved as the concentration of polymer and hydroquinone‐HMTA increased. It still has a very dense microscopic three‐dimensional network structure after 3 months of aging at 150°C. The gel system can effectively improve the formation profile by plugging the high permeability layer and introducing subsequent water into the undisturbed layer.
Preparation of poly (styrene‐methyl methacrylate)@grafted halloysite microspheres and the properties of its composite fibers
Authors: Yan Xiaofei , Song Lixiang , Zhu Chenyan , Li Jiawei , Qi Dongming
Published: July 2022

It has become a hotspot that microfibrils with a high aspect ratio have a good reinforcement effect on the composite fibers. To prepare the micro‐fibrillation composite fibers with excellent performance and good dispersity, poly (styrene‐methyl methacrylate)@grafted halloysite nanotubes(PSM@PMHNTs) microspheres were prepared by suspension polymerization method, and the PSM@PMHNTs reinforced composite fibers were prepared by simple blending with polymethylmethacrylate (PMMA). The structure and mechanical properties of the composite fibers were studied by transmission electron microscopy, scanning electron microscopy, dynamic thermo‐mechanical analysis, and universal material testing machine. The results showed that polystyrene grafted halloysite nanotubes (PMHNTs) had good hydrophobicity and were successfully embedded in poly (styrene‐methyl methacrylate) (PSM). The mechanical performance of microfibril composite fiber with PSM@PMHNTs is better when compared that with PMHNTs and PSM, and the elongation at break of the composite fiber has dramatically increased by 120.90% compared to that of pure PMMA. In addition, the mechanical properties of the composite fibers were increased firstly and then decreased with the increase of PMHNTs contents and draft ratios, while the glass transition temperature of the composite fibers had no obvious changes. The composite fiber has the best mechanical properties when the content of PMHNTs is 1.0 wt% and the draft ratio is 6, and the tensile strength and elongation at break were 26.94% and 256.36% higher than that of pure PMMA, respectively.
Research Progress on Lignocellulosic Biomass Degradation Catalyzed by Enzymatic Nanomaterials
Authors: Luo Hangyu , Liu Xiaofang , Yu Dayong , Yuan Junfa , Tan Jinyu , Li Hu
Published: July 2022

Lignocellulose biomass (LCB) has extensive applications in many fields such as bioenergy, food, medicines, and raw materials for producing value‐added products. One of the keys to efficient utilization of LCB is to obtain directly available oligo‐ and monomers (e. g., glucose). With the characteristics of easy recovery and separation, high efficiency, economy, and environmental protection, immobilized enzymes have been developed as heterogeneous catalysts to degrade LCB effectively. In this review, applications and mechanisms of LCB‐degrading enzymes are discussed, and the nanomaterials and methods used to immobilize enzymes are also discussed. Finally, the research progress of lignocellulose biodegradation catalyzed by nano‐enzymes was discussed.
Ligand‐Dissociation‐Type N,N‐Dimethylaminopyrene Probes for In‐Situ Site‐Specific Protein Labeling
Authors: Tsuda Tomohito , Arai Atsushi , Kita Masaki
Published: July 2022

To develop practical methods for in‐situ labeling of target proteins and to analyze their binding modes with bioactive ligands, 6‐N,N‐dimethylaminopyrene‐N‐acyl‐N‐alkylsulfonamide‐4,8‐diazacyclononyne (dmpy‐NASA‐DACN) tags were synthesized. Strain‐promoted azide‐alkyne cyclization with azide‐conjugated ligands (biotin and sulfonamide) gave ligand‐dissociation‐type dmpy probes. With these probes, specific labeling of avidin and human carboxylase 1 (hCA1) proceeded even in the presence of cell lysate proteins in ca. 10% RIPA buffer. Affinity purification, in‐gel tryptic digestion on polystyrene gel, and MALDI MS analysis established the dmpy‐labeled positions of target proteins. Molecular modeling studies also supported why the dmpy‐labeling reactions proceeded site‐specifically near ligand‐binding sites on the target proteins. Our findings might contribute to the development of chemical probes that specifically label various biomacromolecules in cells.
Conformal Lithium Peroxide Growth Kinetically Driven by MoS2/MoN Heterostructures Towards High‐Performance Li−O2 Batteries
Authors: Gu Yuting , Ma Yong , Wei Le , Lian Yuebin , He Ying , Su Yanhui , Li Xinjian , Peng Yang , Deng Zhao
Published: July 2022

The morphological control and spatial accommodation of Li2O2 discharge products on the oxygen cathode are crucial to bolstering both the Coulombic and round‐trip efficiencies of Li−O2 batteries. Herein, MoS2/MoN heterostructures are constructed on carbon cloth to serve as the freestanding and binder‐free oxygen cathode for Li−O2 batteries, lending a low charge/discharge polarization of 0.79 V, a large specific capacity of 9.04 mAh cm−2, and a superb cycling stability beyond 800 h. Through comprehensive microscopic, electroanalytical and density function theory analyses, the superb electrochemical performance is attributed to the formation of a conformal and amorphous Li2O2 layer, which is kinetically driven in virtue of the higher electric conductivity of MoN and stronger LiO2 intermediate adsorption on the heterostructures. This work advocates the merits of interfacial engineering to enhance the performance of Li−O2 batteries by manipulating the discharge product formation.
Representation of indigenous languages employing a religious screen for the discursive construction of students' postcolonial national identities: A curious case of ‘internal colonisation’ and ‘cultural invasion’ in Pakistani schools
Authors: Qazi M. Habib , Javid Choudhary Z. , Ullah Inayat
Published: July 2022

This study problematises the discourses of Pakistan's national curriculum textbooks to investigate how they represent Pakistan's indigenous languages/cultures through the prism of religion to constitute secondary school students' particular postcolonial linguistic identities. It also draws on the perspectives of 12 teachers and 424 students to record their responses. Taking insights from Paulo Freire's cultural invasion, Robert Blauner's internal colonisation and selected postcolonial perspectives, the study notes a dynamic interplay of the sampled textbooks, schoolteachers and the school as a site of discursive social practices. Jointly, they position students within an exclusionary homogenous Urdu‐loving group—a language which is represented as Arabic's tributary. Indigenous languages are recognised, however, as an adjunct to Arabic and Urdu, emphasising their role in the proselytisation of Islam in the region. Similarly, fine arts and indigenous cultural festivals are represented from a particular religious lens. The students strongly identify with this curious case of internal colonisation and cultural invasion, and support it. They exhibit self‐righteousness and aversion towards linguistic/cultural pluralism and minorities, which entails implications for Pakistan's national cohesion and educational parlance of equity and inclusivity.