bluuebunny/crossref_metadata_2025 huggingface dataset:
Sound production in recorderlike instruments. I. Dimensionless amplitude of the internal acoustic field
Authors: Verge Marc-Pierre , Fabre Benoit , Hirschberg A. , Wijnands A. P. J.
Published: July 2002

Data on the internal acoustic pressure signals in an experimental recorderlike flue organ pipe are presented. A dimensionless representation appears to be a powerful basis for the analysis of these data. The dimensionless amplitude of the fundamental is, for a given geometry, a function of the Strouhal number only. For the first hydrodynamic mode of the jet, this amplitude is independent of the acoustic mode involved. The dimensionless amplitude of the second harmonic displays two different behaviors, depending on whether the jet is laminar or turbulent. This specific Strouhal number dependency implies a strong influence of the distance W from the flue exit to the labium on the timbre of recorderlike instruments. In recorders the ratio W/h, where h is the height of the flue exit, is adjusted by craftsmen to a value close to 4. This specific ratio ensures an optimal harmonic content to noise ratio in the produced sound. Increasing the distance W yields a more powerful sound but at the expense of additional turbulence noise. For these large ratios W/h, transitions between different hydrodynamic modes of the jet are observed at low blowing pressures. This phenomenon is avoided by the choice of a recorderlike geometry.
Perceptual segregation of a harmonic from a vowel by interaural time difference and frequency proximity
Authors: Darwin C. J. , Hukin R. W.
Published: July 2002

The five experiments reported here examine the conditions under which sounds differing in their interaural time difference (ITD) are segregated for the purposes of perceiving a vowel’s identity. Experiment 1 confirms previous findings that (i) a difference in ITD provides only a very weak cue for segregating a vowel’s 500-Hz harmonic from the remainder of an isolated vowel; (ii) embedding the harmonic in a series of 500-Hz tones produces some segregation, which is enhanced if the harmonic and the tones differ in ITD from the rest of the vowel; and (iii) when these latter sounds are presented in the same block as isolated vowels, they facilitate segregation of the harmonic by ITD in the isolated vowels. The subsequent experiments show that this last effect, across-trial facilitation, is only produced by sounds which cue both the frequency and the ITD of the harmonic; either alone is insufficient. We also show that: (i) a single cue tone at the frequency of the harmonic is sufficient to facilitate the use of ITD in grouping; (ii) sequential organization by frequency proximity dominates over sequential organization by ITD when simultaneous sound sources are present; and (iii) the effectiveness of a cue tone can be abolished by capturing it into a synchronous harmonic complex. The experiments clarify the conditions under which ITDs contribute to the segregation of simultaneous sounds.
Focusing and imaging using eigenfunctions of the scattering operator
Authors: Mast T. Douglas , Nachman Adrian I. , Waag Robert C.
Published: July 2002

An inverse scattering method that uses eigenfunctions of the scattering operator is presented. This approach provides a unified framework that encompasses eigenfunction methods of focusing and quantitative image reconstruction in arbitrary media. Scattered acoustic fields are described using a compact, normal operator. The eigenfunctions of this operator are shown to correspond to the far-field patterns of source distributions that are directly proportional to the position-dependent contrast of a scattering object. Conversely, the eigenfunctions of the scattering operator specify incident-wave patterns that focus on these effective source distributions. These focusing properties are employed in a new inverse scattering method that represents unknown scattering media using products of numerically calculated fields of eigenfunctions. A regularized solution to the nonlinear inverse scattering problem is shown to result from combinations of these products, so that the products comprise a natural basis for efficient and accurate reconstructions of unknown inhomogeneities. The corresponding linearized problem is solved analytically, resulting in a simple formula for the low-pass-filtered scattering potential. The linear formula is analytically equivalent to known filtered-backpropagation formulas for Born inversion, and, at least in the case of small scattering objects, has advantages of computational simplicity and efficiency. A similarly efficient and simple formula is derived for the nonlinear problem in which the total acoustic pressure can be determined based on an estimate of the medium. Computational results illustrate focusing of eigenfunctions on discrete and distributed scattering media, quantitative imaging of inhomogeneous media using products of retransmitted eigenfunctions, inverse scattering in an inhomogeneous background medium, and reconstructions for data corrupted by noise.
Radiation forces between two bubbles in a compressible liquid
Authors: Doinikov A. A. , Zavtrak S. T.
Published: July 2002

The expression for the interaction force exerted by a sound field between two gas bubbles, allowing for the compressibility of the surrounding liquid, is derived. The bubble radii are considered to be small compared to the distance l between the equilibrium centers of the bubbles and the wavelength λ of sound, while the ratio of l to λ is assumed to be arbitrary. For an incompressible liquid, the interaction force, usually called the mutual or secondary Bjerknes force, is known to be inversely proportional to l2. It is found that when it is taken into account, the compressibility of the liquid gives rise to two long-range terms inversely proportional to l; one of these, like the Bjerknes force, is directed along the line joining the centers of the bubbles, and the other is in the direction of the gradient of an incident field. The refined expression of the interaction force is used for studies of the relative motion of the two bubbles, resulting from their radiative interaction, in a plane traveling wave and a plane standing wave. It is shown that the long-range terms can cause the bubbles to form stable bound pairs with a fixed separation between the bubbles.
Are inner or outer hair cells the source of summating potentials recorded from the round window?
Authors: Durrant John D. , Wang Jian , Ding D. L. , Salvi Richard J.
Published: July 2002

The relative contribution of inner hair cells (IHCs) and outer hair cells (OHCs) to the production of the summating potential (SP) is unresolved in the literature. Since OHCs in the base of the cochlea have been reported to produce little dc receptor potential except at very high sound pressure levels [, J. Physiol (London) 284, 261–290 (1983)], the IHCs appear to be the dominant source of the SP. However, results of intracochlear recordings are conflicting, although deriving from measurements in different turns of the cochlea [e.g., , J. Physiol. (London) 284, 261–290 (1983) versus Sensory Transduction (1992)]. To determine which type of hair cells is the dominant source of the SP recorded at the round window, we used carboplatin to selectively destroy IHCs or a combination of IHCs and OHCs in the chinchilla. Related work, using measurements of distortion product otoacoustic emissions and cochlear potentials to assess the functional status of the OHCs served to validate this animal model [, Hearing Res. 96(1-2), 71–82 (1996)]. The SP, cochlear microphonic (CM), and compound action potential (CAP) were recorded from the round window, and cochleograms were determined using well-established histological methods. The results were reasonably distinctive among three groups of ears—control (from untreated normal chinchillas), IHC–loss (extensive IHC loss with minor or no loss of OHCs), and IHC–OHC loss (total IHC loss plus extensive loss of OHCs over the basal half of the cochlea). Ears of chinchillas in the IHC loss group had a decrease of over 50% in SP output compared to control ears with the exact reduction depending somewhat upon the stimulus conditions. Ears in the IHC+OHC loss group, nevertheless, showed even further reduction in SP output which was clearly attributable to destruction of OHCs in the cochlear base. It was concluded that, although the IHCs are responsible for a greater contribution of dc-receptor potential to the SP recorded at the round window, a significant contribution is made by the OHCs, as well. The results suggest, specifically, that the round window “sees” SP output roughly in inverse proportion to the IHC:OHC. Lastly, the complexity of SP production, as recorded from the round window, precludes a completely straightforward interpretation of the SP:CAP in clinical ECochG.
Stress effect on boundary conditions and elastic wave propagation through an interface between anisotropic media
Authors: Degtyar A. D. , Rokhlin S. I.
Published: July 2002

Elastic wave propagation through a plane interface between two generally anisotropic stressed solids is considered. The case when one solid is replaced with fluid is considered separately due to its importance for the development of immersion techniques for ultrasonic stress determination. The incident wave plane can coincide with or deviate from planes of material symmetry. Static stresses are assumed to be locally homogeneous and to satisfy static boundary conditions. The analysis is applicable for both applied and residual stresses. For numerical implementation a method and an analysis of the reflection-refraction problem on the boundary of separation between two anisotropic solids [Rokhlin et al., J. Acoust. Soc. Am. 79, 906 (1986)] is modified to take stresses into account. Simulations are performed to implement the theory described and to clarify the stress effect on elastic wave interaction with a solid interface. Changes in propagation directions, polarizations, and energy transmission and reflection coefficients due to the presence of stresses are discussed. The stress-induced birefringence is explored quantitatively. Conditions for destructive interference of shear waves are presented.
A microcosm of musical expression: II. Quantitative analysis of pianists’ dynamics in the initial measures of Chopin’s Etude in E major
Authors: Repp Bruno H.
Published: July 2002

Patterns of expressive dynamics were measured in bars 1–5 of 115 commercially recorded performances of Chopin’s Etude in E major, op. 10, No. 3. The grand average pattern (or dynamic profile) was representative of many performances and highly similar to the average dynamic profile of a group of advanced student performances, which suggests a widely shared central norm of expressive dynamics. The individual dynamic profiles were subjected to principal components analysis, which yielded five Varimax-rotated components, each representing a different, nonstandard dynamic profile associated with a small subset of performances. Most performances had dynamic patterns resembling a mixture of several components, and no clustering of performances into distinct groups was apparent. Some weak relationships of dynamic profiles with sociocultural variables were found, most notably a tendency of female pianists to exhibit a greater dynamic range in the melody. Within the melody, there were no significant relationships between expressive timing [, J. Acoust. Soc. Am. 104, 1085–1100 (1998)] and expressive dynamics. These two important dimensions seem to be controlled independently at this local level and thus offer the artist many degrees of freedom in giving a melody expressive shape.
Effects of categorization and discrimination training on auditory perceptual space
Authors: Guenther Frank H. , Husain Fatima T. , Cohen Michael A. , Shinn-Cunningham Barbara G.
Published: July 2002

Psychophysical phenomena such as categorical perception and the perceptual magnet effect indicate that our auditory perceptual spaces are warped for some stimuli. This paper investigates the effects of two different kinds of training on auditory perceptual space. It is first shown that categorization training using nonspeech stimuli, in which subjects learn to identify stimuli within a particular frequency range as members of the same category, can lead to a decrease in sensitivity to stimuli in that category. This phenomenon is an example of acquired similarity and apparently has not been previously demonstrated for a category-relevant dimension. Discrimination training with the same set of stimuli was shown to have the opposite effect: subjects became more sensitive to differences in the stimuli presented during training. Further experiments investigated some of the conditions that are necessary to generate the acquired similarity found in the first experiment. The results of these experiments are used to evaluate two neural network models of the perceptual magnet effect. These models, in combination with our experimental results, are used to generate an experimentally testable prediction concerning changes in the brain’s auditory maps under different training conditions.
Comparison between electroglottography and electromagnetic glottography
Authors: Titze Ingo R. , Story Brad H. , Burnett Gregory C. , Holzrichter John F. , Ng Lawrence C. , Lea Wayne A.
Published: July 2002

Newly developed glottographic sensors, utilizing high-frequency propagating electromagnetic waves, were compared to a well-established electroglottographic device. The comparison was made on four male subjects under different phonation conditions, including three levels of vocal fold adduction (normal, breathy, and pressed), three different registers (falsetto, chest, and fry), and two different pitches. Agreement between the sensors was always found for the glottal closure event, but for the general wave shape the agreement was better for falsetto and breathy voice than for pressed voice and vocal fry. Differences are attributed to the field patterns of the devices. Whereas the electroglottographic device can operate only in a conduction mode, the electromagnetic device can operate in either the forward scattering (diffraction) mode or in the backward scattering (reflection) mode. Results of our tests favor the diffraction mode because a more favorable angle imposed on receiving the scattered (reflected) signal did not improve the signal strength. Several observations are made on the uses of the electromagnetic sensors for operation without skin contact and possibly in an array configuration for improved spatial resolution within the glottis.
Fast analysis of transient acoustic wave scattering from rigid bodies using the multilevel plane wave time domain algorithm
Authors: Ergin A. A. , Shanker B. , Michielssen E.
Published: July 2002

The analysis of transient wave scattering from rigid bodies using integral equation-based techniques is computationally intensive: if carried out using classical schemes, the evaluation of the velocity potential on the surface of a three-dimensional scatterer, represented in terms of Ns spatial basis functions for Nt time steps, requires O(NtNs2) operations. The recently developed plane wave time domain (PWTD) algorithm permits the rapid evaluation of transient fields that are generated by bandlimited source distributions. It has been shown that incorporation of the PWTD algorithm into integral equation-based solvers in a two-level setting reduces the computational complexity of a transient analysis to O(NtNs1.5 log Ns). In this paper, it is shown that casting the PWTD scheme into a multilevel framework permits the analysis of transient acoustic surface scattering phenomena in O(NtNs log2 Ns) operations using O(NtNs) memory. Numerical examples that demonstrate the efficacy of the multilevel implementation are also presented.
Modal control of beam flexural vibration
Authors: Rizet Nicolas , Brissaud Michel , Gonnard Paul , Béra Jean-Christophe , Sunyach Michel
Published: July 2002

An active control system was developed to control the flexural vibrations of a beam with a modal filtering with only one secondary actuator. Segmented piezoelectric actuators and sensors were used for driving and sensing the bending beam vibrations. The primary actuator was fed by a broadband random disturbance signal in order to excite the first five modes of the structure. However, only the second to fifth modes were controlled. The control algorithm was implemented on a DSP board and the input and output signals were filtered using high order low pass filters. These filters, implemented on the DSP board avoid the degrading effect on the control performances of the higher order modes and which are not controlled. The modal filtering was achieved by computing. To this end, it is based on a previous identification procedure. This latter models, in one step, the dynamics of the structure and also the transfer function of the electronic circuits of the controller. The identified filtered modes were then used to compute the gain matrix using a LQR technique (linear quadratic regulator). Simulations of the active control were carried out and practical implementation of the control algorithms was performed. Experimental and simulation results were then compared and discussed.
Boltzmann and the Beginnings of Linear Viscoelasticity
Authors: Markovitz Hershel
Published: July 2002

This paper was presented, in part, as a plenary lecture at the Seventh International Congress on Rheology at Gothenburg, Sweden on August 23, 1976 in observance of the centenary of Boltzmann's superposition principle.
Extensional Flow of Polymer Melts
Authors: Shroff Ramesh N. , Cancio L. V. , Shida Mitsuzo
Published: July 2002

The apparent uniaxial extensional viscosity or elongational viscosity, ηE, of several polymer melts in a wide range of temperatures was determined as a function of strain rate, ε̇, using Cogswell's analysis of converging flow at the die entry. In particular, ηE was derived from knowledge of the dependence of the steady-flow viscosity as well as the entrance pressure drop, δP0, on shear rate. Quantitative agreement was found in ηE−ε̇ dependence derived from the convergent flow analysis (CFA) along with that measured from isothermal melt-spinning experiments for melts of high-density and low-density polyethylene, polypropylene, and polystyrene. Further support of CFA comes from the finding here that the normalized entrance pressure drop, δP0/τ, is uniquely related to the vortex angle in a manner similar to that determined from flow visualization studies by Ballenger and White. Here τ is the shear stress at the die wall. Additionally, the flow activation energy in extension is found to be equal to that in shear for melts of low-density polyethylene, polypropylene, and polystyrene. Such observations are in line with the earlier results of Munsted on polystyrene melts. An anomaly exists for high-density polyethylenes since ηE increased with increases in temperature above a critical temperature. Finally, the shapes of extensional flow curves are found to be similar to the published data, although an exception such as low-melt-index, low-density polyethylene, where ηE decreases with ε̇, is cited.
Birefringence of amorphous polymers. V. Dynamic measurements on poly(α-methyl styrene) and polycarbonate
Authors: Inoue Tadashi , Hwang Eui Jeong , Osaki Kunihiro
Published: July 2002

The complex Young’s modulus, E*(ω), and the complex strain-optical coefficient, O*(ω), of poly(α-methyl styrene), PMS, and Bisphenol A polycarbonate, PC, were measured over the frequency range of 1–130 Hz around the glass-to-rubber transition point. The real part of O*(ω), O′, of PMS is negative over the entire temperature range considered and the imaginary part, O″, changes its sign from negative to positive with decreasing temperature. Both O′ and O″ of PC are positive over the entire temperature range used. These results are qualitatively different from those for polystyrene. The data were analyzed with a modified stress-optical rule and the complex modulus was separated into two components (denoted by R and G). The G component, which is located in the glassy zone, is related to the high glass modulus, and the shapes of the G components of PMS, PC, and PS are very similar to each other. The R component, located at the long time end of the glass-to-rubber transition zone of PC, is quite different from those of PS and PMS. The difference is mainly due to differences in the plateau modulus, which for PC is about ten times higher than that of PS. The stress-optical coefficient of the R component, CR, varies much more with the molecular structure, but the coefficient of the G component, CG, is positive and almost constant for these polymers.
Prevalence of Antiphospholipid Antibodies and Association With Incident Cardiovascular Events
Authors: Zuo Yu , Navaz Sherwin , Liang Wenying , Li Chun , Ayers Colby R. , Rysenga Christine E. , Harbaugh Alyssa , Norman Gary L. , Solow E. Blair , Bermas Bonnie , Akinmolayemi Oludamilola , Rohatgi Anand , Karp David R. , Knight Jason S. , de Lemos James A.
Published: April 2023

Importance

The prevalence of antiphospholipid antibodies (aPL) and their association with future atherosclerotic cardiovascular disease (ASCVD) risk has yet to be thoroughly investigated.

Objective

To determine the association between measurements of aPL at a single time point and ASCVD risk in a diverse population.

Design, Setting, and Participants

This cohort study measured 8 aPL (anticardiolipin [aCL] IgG/IgM/IgA, anti–beta-2 glycoprotein I [aβ2GPI] IgG/IgM/IgA, and antiphosphatidylserine/prothrombin [aPS/PT] IgG/IgM) by solid-phase assays in plasma from participants of the Dallas Heart Study (DHS) phase 2, a multiethnic, population-based cohort study. Blood samples were collected between 2007 and 2009. The median follow-up was 8 years. Statistical analysis was performed from April 2022 to January 2023.

Main Outcomes and Measures

Associations of aPL with future ASCVD events (defined as first nonfatal myocardial infarction, first nonfatal stroke, coronary revascularization, or death from cardiovascular cause) were assessed by Cox proportional hazards models, adjusting for known risk factors, medications, and multiple comparisons.

Results

Among the 2427 participants (mean [SD] age, 50.6 [10.3] years; 1399 [57.6%] female; 1244 [51.3%] Black, 339 [14.0%] Hispanic, and 796 [32.8%] White), the prevalence of any positive aPL tested at a single time point was 14.5% (353 of 2427), with approximately one-third of those detected at a moderate or high titer; aCL IgM had the highest prevalence (156 individuals [6.4%]), followed by aPS/PT IgM (88 [3.4%]), aβ2GPI IgM (63 [2.6%]), and aβ2GPI IgA (62 [2.5%]). The IgA of aCL (adjusted hazard ratio [HR], 4.92; 95% CI, 1.52-15.98) and aβ2GPI (HR, 2.91; 95% CI, 1.32-6.41) were independently associated with future ASCVD events. The risk further increased when applying a positivity threshold of at least 40 units (aCL IgA: HR, 9.01 [95% CI, 2.73-29.72]; aβ2GPI IgA: HR, 4.09 [95% CI, 1.45-11.54]). Levels of aβ2GPI IgA negatively correlated with cholesterol efflux capacity (r = −0.055; P = .009) and positively correlated with circulating oxidized LDL (r = 0.055; P = .007). aβ2GPI IgA–positive plasma was associated with an activated endothelial cell phenotype as evidenced by increased surface expression of surface E-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1.

Conclusions and Relevance

In this population-based cohort study, aPL detectable by solid-phase assays were present in a substantial proportion of adults; positive aCL IgA and aβ2GPI IgA at a single time point were independently associated with future ASCVD events. Longitudinal studies with serial aPL measurements are needed to further explore these findings.
Trends in Telehealth Visits During Pregnancy, 2018 to 2021
Authors: Acharya Mahip , Ali Mir M. , Hayes Corey J. , Bogulski Cari A. , Magann Everett F. , Eswaran Hari
Published: April 2023

This cross-sectional study examines trends of prenatal telehealth visits in pregnancy and explores patient characteristics associated with the number of prenatal telehealth visits.
Plaque Macrophage‐Targeting Nanosystems with Cooperative Co‐Regulation of ROS and TRAF6 for Stabilization of Atherosclerotic Plaques
Authors: Yang Qian , Jiang Hong , Wang Yue , Leng Xiao , Wang Yantang , Tong Jie , Zhou Yang , Mo Chunfen , Peng Jinrong , Gao Huile
Published: April 2023

Chronic inflammatory microenvironment is the predominant milieu that promotes the progression of atherosclerosis (AS). However, targeted regulation of the chronic proinflammatory milieu still needs to be improved. In this study, macrophage‐targeting nanosystems composed of 37pA peptide embedded–Pt lipid nanoparticles (37pA‐PtLNP) and tumor necrosis factor‐associated factor 6 (TRAF6) inhibitor (6877002)‐loaded poly(ε‐caprolactone)‐b‐polyethylene glycol‐b‐poly(ε‐caprolactone) (PCEC) are constructed with 37pA peptide embedded–lipid coating (37pA‐LNP/6877002), to stabilize atherosclerotic lesions. The cooperative regulation effects of these nanosystems in achieving reactive oxygen species (ROS) scavenging and inflammatory signaling inhibition are investigated. 37pA‐PtLNP effectively scavenges several ROS, however, also promotes the expression of iNOS. The introduction of 37pA‐LNP/6877002 inhibits the activities of TRAF6, a downstream intracellular factor of the CD40L‐CD40‐TRAF6 axis, to decrease the proportion of the proinflammatory M1 macrophage phenotype, which is further downregulated by combined treatment with 37pA‐PtLNP. The combination of 37pA‐PtLNP and 37pA‐LNP/6877002 not only counteracts 37pA‐PtLNP–induced iNOS upregulation but also alleviates the chronic inflammatory microenvironment by reducing the expression of proinflammatory cytokines and chemokines. The anti‐AS efficacy in vivo on ApoE−/− mice further demonstrates that the combination of 37pA‐PtLNP and 37pA‐LNP/6877002 targetedly modulates the atherosclerotic plaque microenvironment, achieving stabilization of lesions with minimal progression. This study provides a promising strategy for AS management.
Sodium‐Based Concave Metasurfaces for High Performing Plasmonic Optical Filters by Templated Spin‐on‐Sodiophobic‐Glass
Authors: Yang Yuhan , Fu Hanyu , Su Huanhuan , Chen Shuying , Wu Shan , Liang Jie , Wei Tianqi , Wang Yang , Zhu Shining , Zhu Jia , Zhou Lin
Published: April 2023

Optical filters have aroused tremendous excitement in advanced photonic instruments and modern digital displays due to their flexible capability of spectrum manipulation. Plasmonic metasurfaces of narrow bandwidth, high spectral contrast, and robust structure tolerance are highly desired for optical filtration (especially in the visible regime) but rather challenging as large spectral broadening from intrinsic ohmic loss and design/fabrication deviations. Here the high‐performing sodium‐based metasurfaces are demonstrated for optical filtration across 450 to 750 nm by unique structure design of spatially decoupled concave surfaces and precise fabrication through templated solidification of liquid metals. Thanks to the distinct suppression of metallic loss as well as fabrication tolerance of interfacial structures, the as‐prepared concave metasurfaces enable a minimum linewidth of ≈15 nm, a maximal optical contrast of ≈93%, and a high measure‐to‐design spectral match ratio ≈1500. These results have for the first time pushed the operation wavelengths of sodium‐based plasmonic devices from infrared to visible which in turn demonstrates the capability of filling the blank of commercial dielectric optical filters thus far.
Polarization‐Tuned Fano Resonances in All‐Dielectric Short‐Wave Infrared Metasurface
Authors: Attiaoui Anis , Daligou Gérard , Assali Simone , Skibitzki Oliver , Schroeder Thomas , Moutanabbir Oussama
Published: April 2023

The short‐wave infrared (SWIR) is an underexploited portion of the electromagnetic spectrum in metasurface‐based nanophotonics despite its strategic importance in sensing and imaging applications. This is mainly attributed to the lack of material systems to tailor light–matter interactions in this range. Herein, this limitation is addressed and an all‐dielectric silicon‐integrated metasurface enabling polarization‐induced Fano resonance control at SWIR frequencies is demonstrated. The platform consists of a 2D Si/Ge0.9Sn0.1 core/shell nanowire array on a silicon wafer. By tuning the light polarization, it is shown that the metasurface reflectance can be efficiently engineered due to Fano resonances emerging from the electric and magnetic dipoles competition. The interference of optically induced dipoles in high‐index nanowire arrays offers additional degrees of freedom to tailor the directional scattering and the flow of light while enabling sharp polarization‐modulated resonances. This tunablity is harnessed in nanosensors yielding an efficient detection of 10−2 changes in the refractive index of the surrounding medium.
Heteroatom‐Driven Coordination Fields Altering Single Cerium Atom Sites for Efficient Oxygen Reduction Reaction
Authors: Yin Leilei , Zhang Shuai , Sun Mingzi , Wang Siyuan , Huang Bolong , Du Yaping
Published: April 2023

For current single‐atom catalysts (SACs), modulating the coordination environments of rare‐earth (RE) single atoms with complex electronic orbital and flexible chemical states is still limited. Herein, cerium (Ce) SAs supported on a P, S, and N co‐doped hollow carbon substrate (Ce SAs/PSNC) for the oxygen reduction reaction (ORR) are reported. The as‐prepared Ce SAs/PSNC possesses a half‐wave potential of 0.90 V, a turnover frequency value of 52.2 s−1 at 0.85 V, and excellent stability for the ORR, which exceeds the commercial Pt/C and most recent SACs. Ce SAs/PSNC‐based liquid zinc–air batteries (ZABs) exhibit a high and stable open‐circuit voltage of 1.49 V and a maximum power density of 212 mW cm−2. As the catalyst of the air cathode, it also displays remarkable performance in flexible electronic devices. Theoretical calculations reveal that the introduction of S and P sites induces significant electronic modulations to the Ce SA active sites. The P and S dopings promote the electroactivity of Ce SAs and improve the overall site‐to‐site electron transfer within the Ce SAs/PSNC. This work offers a unique perspective for modulating RE‐based SACs in a complex coordination environment toward superior electrocatalysis and broad applications in energy conversion and storage devices.
Hot Electron Dynamics in MoS2/Pt Van Der Waals Electrode Interface for Self‐Powered Hot Electron Photodetection
Authors: Hong Chengyun , Jang Seo Gyun , Yu Young‐Jun , Kim Ji‐Hee
Published: April 2023

Hot electron photodetection provides a powerful platform for photosensing beyond the bandgap of a semiconductor. High‐performing hot electron photodetection has been reported in 2D transition metal dichalcogenide material‐based devices without the support of plasmonic metal nanostructures but with planar metal electrodes. However, the mechanism driving hot electron dynamics in 2D transition metal dichalcogenide devices has not been explored. Here, we uncover the hot electron transfer in MoS2 and Pt van der Waals (vdW) metal electrodes by transient reflection spectroscopy, revealing a sub‐picosecond transfer time of hot electron and a decelerated recombination process in MoS2 at the below bandgap photoexcitation compared to the pristine MoS2. With an independent photocurrent mapping, the ultralong diffusion is revealed in MoS2/vdW metal electrode and a self‐powered near‐infrared (NIR) photodetector is demonstrated with a high responsivity of 6 mA W−1 and detectivity of 9 × 109 Jones at a wavelength of 1062 nm by integrating Pt and Ag asymmetric vdW electrodes into MoS2. The results will pave the way for the next generation of hot‐electron‐based self‐powered optoelectronic devices.
Cationic Molecular Metal Chalcogenide Ligand‐Passivated Colloidal Quantum Dots and Their Application to Suppressed Dark‐Current Near‐Infrared Photodetectors
Authors: Seo Haewoon , Eun Hyeong Ju , Choi Donghyeuk , Na Hyon Bin , Shim Yeongseok , Heo Junseok , Cho Kyung‐Sang , Kim Jong H. , Kim Sang‐Wook
Published: April 2023

The surface of colloidal‐type quantum dots (QDs) is protected with surfactants to maintain their nanoscale size and dispersion in various solvents. Such protection is advantageous to the processability of the dots, but the surfactants also act as insulators, thereby adversely affecting the electrical properties of the resulting devices. Anion‐type molecular metal chalcogenide complexes (MCCs) have been developed as an alternative to these surfactants. However, anionic ligands limit the charges of the resulting QDs to negative values; thus, additional processes are required to compensate for these charges. Herein, this work prepares cationic‐type dimetal diselenium perchlorate MCCs (M2Se2(ClO4)2, M = Mn, Zn, and Sn) and applies them to stabilize colloidal QDs. The resulting M2Se2‐PbS QDs are then used to fabricate near‐infrared photodetectors (NIR‐PDs). The devices exhibit remarkably suppressed dark current densities (JD) of as low as 4.92 × 10−10 A cm−2 when compared with PDs based on 1,2 ethandithiol‐PbS (EDT‐PbS) (JD = 1.41 × 10−8 A cm−2). In addition, the devices exhibit a high responsivity of 0.07 A W−1 in response to 950 nm NIR light signals, as well as an excellent specific detectivity of 5.66 × 1012 Jones at 950 nm. Finally, this work fabricates hybrid‐type QD films using cationic and anionic MCC‐PbS QDs and obtains a high external quantum efficiency (EQE) of 13.1%.
An All‐MXene‐Based Flexible, Seamless System with Integrated Wireless Charging Coil, Micro‐Supercapacitor, and Photodetector
Authors: Duan Zhongyi , Hu Chuqiao , Liu Weijia , Liu Jinhai , Chu Zhengyu , Yang Weiqing , Li La , Shen Guozhen
Published: April 2023

Fabrication of miniature‐integrated devices combining energy harvester, energy storage, and various sensors via simple, fast, and efficient ways is strongly desired for the practical application of integrated smart systems. Herein, this work presents a simple one‐step laser scribing method to prepare an all MXene‐based seamlessly integrated system with integrated wireless charging coil, micro‐supercapacitor, and photodetector in a small area of only 1.78 cm2. All the three modules in the integrated system are composed entirely of Ti3C2Tx MXene and are connected with highly conductive MXene wires without additional welding or assembling operation. The energy is first received by the wireless charging coil and then stored in the Zn‐ion micro‐supercapacitor, which is subsequently used to drive the surface‐modified (dodecyl triethoxysilane) DCTES‐MXene‐based photodetector, thus realizing the complete energy cycles. This work conceptually illustrates a simple method for designing and preparing integrated multifunctional wearable devices.
Wake‐Riding Effect‐Inspired Opto‐Hydrodynamic Diatombot for Non‐Invasive Trapping and Removal of Nano‐Biothreats
Authors: Xiong Jianyun , Shi Yang , Pan Ting , Lu Dengyun , He Ziyi , Wang Danning , Li Xing , Zhu Guoshuai , Li Baojun , Xin Hongbao
Published: April 2023

Contamination of nano‐biothreats, such as viruses, mycoplasmas, and pathogenic bacteria, is widespread in cell cultures and greatly threatens many cell‐based bio‐analysis and biomanufacturing. However, non‐invasive trapping and removal of such biothreats during cell culturing, particularly many precious cells, is of great challenge. Here, inspired by the wake‐riding effect, a biocompatible opto‐hydrodynamic diatombot (OHD) based on optical trapping navigated rotational diatom (Phaeodactylum tricornutum Bohlin) for non‐invasive trapping and removal of nano‐biothreats is reported. Combining the opto‐hydrodynamic effect and optical trapping, this rotational OHD enables the trapping of bio‐targets down to sub‐100 nm. Different nano‐biothreats, such as adenoviruses, pathogenic bacteria, and mycoplasmas, are first demonstrated to be effectively trapped and removed by the OHD, without affecting culturing cells including precious cells such as hippocampal neurons. The removal efficiency is greatly enhanced via reconfigurable OHD array construction. Importantly, these OHDs show remarkable antibacterial capability, and further facilitate targeted gene delivery. This OHD serves as a smart micro‐robotic platform for effective trapping and active removal of nano‐biothreats in bio‐microenvironments, and especially for cell culturing of many precious cells, with great promises for benefiting cell‐based bio‐analysis and biomanufacturing.
Goldenrod herbariomics: Hybrid‐sequence capture reveals the phylogeny of Solidago
Authors: Semple John C. , McMinn‐Sauder Harper , Stover Melissa , Lemmon Alan R. , Lemmon Emily Moriarty , Beck James B.
Published: April 2023

Premise

The phylogenetic relationships among the ca. 138 species of goldenrods (Solidago; Asteraceae) have been difficult to infer due to species richness, and shallow interspecific genetic divergences. This study aims to overcome these obstacles by combining extensive sampling of goldenrod herbarium specimens with the use of a custom Solidago hybrid‐sequence capture probe set.

Methods

A set of tissues from herbarium samples comprising ca. 90% of Solidago species was assembled and DNA was extracted. A custom hybrid‐sequence capture probe set was designed, and data from 854 nuclear regions were obtained and analyzed from 209 specimens. Maximum likelihood and coalescent approaches were used to estimate the genus phylogeny for 157 diploid samples.

Results

Although DNAs from older specimens were both more fragmented and produced fewer sequencing reads, there was no relationship between specimen age and our ability to obtain sufficient data at the target loci. The Solidago phylogeny was generally well‐supported, with 88/155 (57%) nodes receiving ≥95% bootstrap support. Solidago was supported as monophyletic, with Chrysoma pauciflosculosa identified as sister. A clade comprising Solidago ericameriodes, Solidago odora, and Solidago chapmanii was identified as the earliest diverging Solidago lineage. The previously segregated genera Brintonia and Oligoneuron were identified as placed well within Solidago. These and other phylogenetic results were used to establish four subgenera and fifteen sections within the genus.

Conclusions

The combination of expansive herbarium sampling and hybrid‐sequence capture data allowed us to quickly and rigorously establish the evolutionary relationships within this difficult, species‐rich group.
Setting‐based skin cancer prevention at the workplace: A survey among German outdoor workers
Authors: Görig Tatiana , Breitbart Eckhard W. , Drexler Hans , Diehl Katharina
Published: April 2023

Background

Outdoor workers are at increased risk of developing skin cancer. Setting‐based prevention at the workplace can reduce the UV exposure of outdoor workers through appropriate technical or organizational measures. We explored the implementation of setting‐based UV protection at the workplace in Germany from the perspective of outdoor workers.

Methods

A Germany‐wide sample of 319 outdoor workers from different employment sectors (64.3% male) was surveyed via telephone on different technical and organizational measures for UV protection at the workplace. Bivariate analyses were performed to explore associations with job‐related characteristics.

Results

In general, 28.0% were rarely or never provided with a place in the shade during working hours, and 27.4% rarely or never provided with a shaded place during breaks. One‐third had rarely or never the opportunity to work in the shade on hot summer days. Overall, 51.9% reported receiving protective clothing from their employer, 45.5% were provided with headgear, and 25.1% with sunscreen. About one‐third had often or always the option of starting work earlier in the morning on hot summer days to work less in the sun, while 18.6% had to work overtime on such days. One‐third (35.4%) had been educated at work about risks of solar radiation and sun protection measures.

Conclusions

Our study is among the first to present findings on the implementation of different setting‐based UV protection measures at the workplace and provides starting points for employers and policy makers to improve UV protection at the workplace.
Hippocampal metabolic subregions and networks: Behavioral, molecular, and pathological aging profiles
Authors: Maleki Balajoo Somayeh , Eickhoff Simon B. , Masouleh Shahrzad Kharabian , Plachti Anna , Waite Laura , Saberi Amin , Bahri Mohamed Ali , Bastin Christine , Salmon Eric , Hoffstaedter Felix , Palomero‐Gallagher Nicola , Genon Sarah
Published: April 2023

INTRODUCTION

Hippocampal local and network dysfunction is the hallmark of Alzheimer's disease (AD).

METHODS

We characterized the spatial patterns of hippocampus differentiation based on brain co‐metabolism in healthy elderly participants and demonstrated their relevance to study local metabolic changes and associated dysfunction in pathological aging.

RESULTS

The hippocampus can be differentiated into anterior/posterior and dorsal cornu ammonis (CA)/ventral (subiculum) subregions. While anterior/posterior CA show co‐metabolism with different regions of the subcortical limbic networks, the anterior/posterior subiculum are parts of cortical networks supporting object‐centered memory and higher cognitive demands, respectively. Both networks show relationships with the spatial patterns of gene expression pertaining to cell energy metabolism and AD's process. Finally, while local metabolism is generally lower in posterior regions, the anterior–posterior imbalance is maximal in late mild cognitive impairment with the anterior subiculum being relatively preserved.

DISCUSSION

Future studies should consider bidimensional hippocampal differentiation and in particular the posterior subicular region to better understand pathological aging.
State‐of‐the‐art electrochemical sensors for quantitative detection of pesticides
Authors: Kadu Rashmi Dilip , Keri Rangappa S. , D. H. Nagaraju , Budagumpi Srinivasa
Published: April 2023

Pesticides are hazardous chemicals that are spread on crops to protect from pests or insects. These are widely used in agriculture as well as for domestic purposes, which not only affect plants and animals but also harm the human body. Therefore, detection of these harmful pesticides is of utmost importance. Conventional methods of pesticide detection are costly, time–consuming and need manpower to perform analysis; however, electrochemical sensing of pesticides is emerging as one of the best current approaches. Since, these sensors exhibit the capability of detecting pesticides onsite, easy fabrication, high selectivity and sensitivity, hence are preferred ones from the forensic point of view. Although, there have been several studies conducted on the sensing of pesticides but this study mainly focuses on electrochemical sensing of pesticides using specific nanomaterials such as nanoparticles, nanocomposites, metal–organic framework (MOF) and 2‐dimensional materials. Additionally, this review also comprises of the comparison of analytical conditions including limit of detection of the aforementioned technique, future perspectives and challenges associated with the development of next generation sensors. Therefore this review, in a broad perspective, provides information that would be useful for the fabrication of new electrochemical sensors and their applicability in the fields of chemistry, forensic science, food technology, material science, environmental science, nanoscience and biotechnology. From the study conducted through this review, it was observed that AuNPs are the mostly used nanoparticles where enzymatic nanosensor with coating of AuNPs along with fluorine doped tin oxide exhibited good activity for the detection of pesticides.
Enhanced Fischer–Tropsch synthesis performance on MOFs‐derived Fe‐based catalysts constrained by SiO2
Authors: Chen Tao , Jiang Xiangning , Zhao Ning , Nisa Mehar U. , Li Zhenhua
Published: April 2023

Fischer–Tropsch synthesis (FTS) is an essential technology to produce clean fuel, and catalyst will affect syngas conversion efficiency and product distribution. For traditional oxides‐supported catalysts, the mutual constraint between active metal loading and dispersion at high metal loading is hard to overcome, which will hinder the synthesis of high‐performance FTS catalysts. Herein, we report an efficient method for synthesizing iron‐based catalysts with not only high loading but also high dispersion. By using metal–organic frameworks Fe‐MIL‐88B as the precursor, we synthesized a series of Fe@C@SiO2 catalysts by tuning the amount of tetraethyl orthosilicate (TEOS) through a one‐step method; TEOS was in situ introduced and followed by high‐temperature carbonization. The prepared catalyst possesses a Fe@C core–shell structure with carbon layer encapsulation. Meanwhile, the SiO2 in the catalyst can effectively confine iron particles and avoid the agglomeration of iron species during high‐temperature carbonization. Among these catalysts, the Fe@C@SiO2‐0.005 showed the greatest FTS performance because high iron dispersion was achieved at high iron loading. Further increase SiO2 content enhanced the confinement effect of SiO2 but generated inert Fe2SiO4 species, which decreased the adsorption and activation of reactants and FTS activity.
A compendium of stable hotspots in the CHO genome
Authors: Hilliard William , Lee Kelvin H.
Published: April 2023

The use of targeted integration for industrial CHO cell line development currently requires significant upfront effort to identify genomic loci capable of supporting multigram per liter therapeutic protein production from a limited number of transgene copies. To address this barrier to widespread adoption, we characterized transgene expression from thousands of stable hotspots in the CHO genome using the Thousands of Reporters Integrated in Parallel high‐throughput screening method. This genome‐scale data set was used to define a limited set of epigenetic properties of hotspot regions with sizes on the order of 10 kb. Cell lines with landing pad integrations at eight retargeted hotspot candidates consistently exhibited higher transgene mRNA expression than a commercially viable hotspot in equivalent culture conditions. Initial benchmarking of NISTmAb and trastuzumab productivity from one of these hotspots yielded mAb productivities of approximately 0.7–2 g/L (qP range: 2.9–8.2 pg/cell/day) in small‐scale fed‐batches. These findings indicate the list of hotspot candidates identified here will be a valuable resource for targeted integration platform development within the CHO community.