bluuebunny/crossref_metadata_2025 huggingface dataset:
On the quasi-analytic treatment of hysteretic nonlinear response in elastic wave propagation
Authors: Van Den Abeele Koen E-A , Johnson Paul A. , Guyer Robert A. , McCall Katherine R.
Published: July 2002

Microscopic features and their hysteretic behavior can be used to predict the macroscopic response of materials in dynamic experiments. Preisach modeling of hysteresis provides a refined procedure to obtain the stress–strain relation under arbitrary conditions, depending on the pressure history of the material. For hysteretic materials, the modulus is discontinuous at each stress–strain reversal which leads to difficulties in obtaining an analytic solution to the wave equation. Numerical implementation of the integral Preisach formulation is complicated as well. Under certain conditions an analytic expression of the modulus can be deduced from the Preisach model and an elementary description of elastic wave propagation in the presence of hysteresis can be obtained. This approach results in a second-order partial differential equation with discontinuous coefficients. Classical nonlinear representations used in acoustics can be found as limiting cases. The differential equation is solved in the frequency domain by application of Green’s function theory and perturbation methods. Limitations of this quasi-analytic approach are discussed in detail. Model examples are provided illustrating the influence of hysteresis on wave propagation and are compared to simulations derived from classical nonlinear theory. Special attention is given to the role of hysteresis in nonlinear attenuation. In addition guidance is provided for inverting a set of experimental data that fall within the validity region of this theory. This work will lead to a new type of NDT characterization of materials using their nonlinear response.
Collecting localization response with a virtual acoustic pointer
Authors: Langendijk Erno H. , Bronkhorst Adelbert W.
Published: July 2002

A virtual acoustic pointer may provide a natural way of indicating the apparent position of virtual auditory stimuli. In a localization experiment, listeners were instructed to place an acoustic pointer at the same apparent position as a virtual target. The pointer was generated by filtering a click train (100 ms) with equalized minimum-phase head-related transfer functions (HRTFs). Listeners controlled the position of the pointer with a hand-held stick that rotated about a fixed point. In the baseline condition the target, a 100 ms noise burst, was filtered with the same HRTFs as the pointer. In other conditions, the HRTFs of the target were modeled with three, five, or seven principal components. Target and pointer were never presented simultaneously. Listener’s judgments with the pointer were more accurate than those reported in previous studies requiring verbal responses. The acoustic pointer also seemed to help listeners to resolve front-back confusions. With fewer than seven principal components used to synthesize stimuli, subjects made substantially more front-back confusions and many more errors in elevation, in agreement with previous studies. The results suggest that an acoustic pointer allows more subtle cues for sound localization to be studied. [Work supported by TNO.]
Sensor—actuator tile for underwater surface impedance control studies
Authors: Corsaro Robert D. , Houston Brian , Bucaro Joseph A.
Published: July 2002

An actuator—sensor tile has been developed for use in studies examining the issues involved in actively controlling the reflection and transmission characteristics of generic underwater structures. The tile is 25 cm square and contains a full area actuator, acoustic pressure sensor, and (acoustic particle) velocity sensor. This paper presents the predictive models used in the tile design. Issues addressed include transducer performance, spatial sampling, near-field sensing, internal resonances, and both direct and extraneous coupling mechanisms, all of which can contribute to complicate the system transfer functions. The acoustic characteristics of the final tile were evaluated at the NRL Laboratory for Structural Acoustics (LSA) and these results are compared with predictions.
Stop-consonant and vowel perception in 3- and 4-year-old children
Authors: Ohde Ralph N. , Haley Katarina L.
Published: July 2002

Recent research on 5- to 11-year-old children’s perception of stop consonants and vowels indicates that they can generally identify these sounds with relatively high accuracy from short duration stimulus onsets [Ohde et al., J. Acoust. Soc. Am. 97, 3800–3812 (1995); Ohde et al., J. Acoust. Soc. Am. 100, 3813–3824 (1996)]. The purpose of the current experiments was to determine if younger children, aged 3–4 years, can also recover consonant and vowel features from stimulus onsets. Ten adults, ten 3-year olds, and ten 4-year-olds listened to synthesized syllables composed of combinations of [b d g] and [i u ɑ]. The synthesis parameters included manipulations of the following stimulus variables: formant transition (moving or straight), noise burst (present or absent), and voicing duration (10, 30, or 46 ms). Developmental effects were found for the perception of both stop consonants and vowels. In general, adults identified these sounds at a significantly higher level than children, and perception by 4-year-olds was significantly better than 3-year-olds. A developmental effect of dynamic formant motion was obtained, but it was limited to only the [g] stop consonant. Stimulus duration affected the children’s perception of vowels indicating that they may utilize additional auditory information to a much greater extent than adults. The results support the importance of information in stimulus onsets for syllable identification, and developmental changes in sensitivity to these cues for consonant and vowel perception.
The force between two parallel rigid plates due to the radiation pressure of broadband noise: An acoustic Casimir effect
Authors: Larraza Andrés , Holmes Christopher D. , Susbilla Robert T. , Denardo Bruce
Published: July 2002

Theoretical and experimental results are presented for the force law between two rigid, parallel plates due to the radiation pressure of broadband acoustic noise. The noise is in the band of 5–15 kHz and has an intensity of 133 dB (re: 10−12 W/m2). Excellent quantitative agreement is shown between theory and experiment. These results constitute an acoustic analog for the Casimir effect, which is the force experienced by two closely spaced uncharged conducting plates due to the quantum electromagnetic zero-point field. In contrast to this case, however, band-limited noise can cause the force to be attractive or repulsive as a function of separation between the plates.
Acoustical and mechanical characterization of anisotropic open-cell foams
Authors: Melon M. , Mariez E. , Ayrault C. , Sahraoui S.
Published: July 2002

Acoustical (viscous static permeability, tortuosity, and viscous characteristic length) and mechanical (skeleton viscoelasticity tensor) parameters which characterize the behavior of porous media are provided from measurements along three perpendicular axes. The measurements are performed on cubic samples of open-cell foams. The longitudinal direction is chosen to be parallel to the growth direction of the foam. The results show that the samples tested here exhibit a quasi-axisymmetrical geometry. It appears that a precise description of this type of reticulated polymeric foam must include its anisotropy, especially for vibroacoustic behavior prediction.
Measurements and model of the cat middle ear: Evidence of tympanic membrane acoustic delay
Authors: Puria Sunil , Allen Jont B.
Published: July 2002

In order to better understand the mechanics of tympanic membrane (TM) transduction at frequencies above a few kHz, the middle-ear (ME) impedance measured near the tympanic membrane is studied for three anesthetized cat ears after widely opening the ME cavities (MEC). Three conditions were measured: intact ossicles, drained cochlea, and disarticulated stapes. When the cochlear load is removed from the ME by disarticulating the stapes, the impedance magnitude varies by about ±25 dB in the 5- to 30-kHz range, with peaks and valleys at intervals of ≈5 kHz. These measurements suggest middle-ear standing waves. It is argued that these standing waves reside in the TM. In contrast, the magnitude of the impedance for the intact case varies by less than ±10 dB, indicating that for this case the standing waves are damped by the cochlear load. Since the measurements were made within 2 mm of the TM, standing waves in the ear canal can be ruled out at these frequencies. Although the ME cavities were widely opened, reflections from the ME cavity walls or surrounding structures could conceivably result in standing waves. However, this possibility is ruled out by model predictions showing that such large standing waves in the ME cavity space would also be present in the intact case, in disagreement with the observation that standing waves are damped by cochlear loading. As a first-order approximation, the standing waves are modeled by representing the TM as a lossless transmission line with a frequency-independent delay of 36 μs. The delay was estimated by converting the impedance data to reflectance and analyzing the reflectance group delay. In the model the ossicles are represented as lumped-parameter elements. In contrast to previous models, the distributed and lumped parameter model of the ME is consistent with the measured impedance for all three conditions in the 200-Hz to 30-kHz region. Also in contrast with previous models, the ear-canal impedance is not mass dominated for frequencies above a few kHz. Finally, the present model is shown to be consistent, at high frequencies, with widely accepted transfer functions between (i) the stapes displacement and ear-canal pressure, (ii) the vestibule pressure and ear-canal pressure, and (iii) the umbo velocity and ear-canal volume velocity. An improved understanding of TM mechanics is important to improve hearing aid transducer design, ear-plug design, as well as otoacoustic emissions research.
Ultrasonic splitting of oil-in-water emulsions
Authors: König Ralf , Benes Ewald , Gröschl Martin , Hald Jens
Published: July 2002

Standing resonant ultrasonic wave fields can be utilized for liquid–liquid separation of the dispersed particles and the fluid caused by the acoustic radiation pressure and the induced particle agglomeration or coagulation/coalescence process. For the splitting of oil-in-water emulsions, the available piezoelectric composite transducer technology was improved and a dedicated resonator with crossed plane wave sonication geometry has been developed. The resonator chamber is entirely made of aluminium or tempax glass and the PZT piezoceramic transducer delivers an acoustic energy flow density of up to 24 W/cm2 into the sonication volume. The chosen resonance frequency is kept stable by automatic frequency control utilizing the maximum true power criterion. Physically and chemically well-defined low and high density pure laboratory and also industrially used cooling-lubricating oil-in-water emulsion samples have been investigated. The quality of the ultrasonic-induced particle separation/coagulation process is characterized by physical–chemical analysis of the separated oil- and water phase and by determining the change of the particle size distribution of the initial emulsion due to the ultrasonic treatment. [Work supported by the European Commission, Contract Nos. ERBFMBICT960916 and ERBFMRXCT970156.]
Reverberation in rectangular long enclosures with diffusely reflecting boundaries
Authors: Kang Jian
Published: July 2002

Based on the technique of radiosity, a computer model has been developed for calculating acoustic indices in rectangular enclosures with diffusely reflecting boundaries. The model divides every boundary into a number of patches and replaces patches and receivers with nodes in a network. The energy moving between nodes depends on the form factor between pairs of patches. For a cube, there is good agreement between the model result and classical theories, which can be regarded as a validation of the model. Computations for long enclosures show that (1) with the increase of source–receiver distance the RT30 increases continuously and the early decay time (EDT) increases rapidly until it reaches maximum and then decreases slowly—correspondingly, the decay curves are concave in the near field and then become convex. (2) Air absorption has greater effect on both reverberation and sound attenuation along the length than that with geometrically reflecting boundaries [J. Kang, Acust./acta acust. 82, 509–516 (1996)]. (3) With a constant cross-sectional size, reverberation time reaches a maximum as the aspect ratio tends to 1. (4) With a given amount of absorption, reverbation can vary considerably with various absorption distributions in a cross section. [Work supported by Lloyd Foundation.]
An iterative approach for approximating bubble distributions from attenuation measurements
Authors: Caruthers J. W. , Elmore P. A. , Novarini J. C. , Goodman R. R.
Published: July 2002

A precise theory exists, based on an integral equation, by which acoustic signal attenuation versus frequency, due to a known bubble-density distribution versus bubble radius, may be calculated. Lacking a simple inversion scheme for the integral equation, an approximation which accounts only for attenuation due to resonant bubbles is available (and often applied) to calculate a bubble distribution. An iterative approach for improving on that resonant bubble approximation is presented here. That new approach is based on alternating calculations and corrections between attenuation data and the bubble distribution presumed to have produced it. This iterative technique is tested, first, on two simulated data sets of bubble distributions. It is then applied to attenuation data measured as a function of frequency from 39 to 244 kHz during the Scripps Pier Experiment [Caruthers et al., Proc. 16th Int. Cong. on Acoust., pp. 697–698 (1998)]. The results of the simulations demonstrate the validity of the method by faithfully reproducing the initial distributions for the simulated attenuation data. When applied to the real data, the method leads to a bubble distribution whose use in a direct solution of the integral equation reproduces the measured data with greater accuracy than does the resonant bubble approximation alone.
Dimethylformamidase with a Unique Iron Center
Authors: Arya Chetan K , Ramanathan Gurunath , Vinothkumar Kutti R , Subramanian Ramaswamy
Published: March 2022

N, N
‐Dimethylformamide is an abundant and one of the most used solvents in the chemical industry. The enzyme dimethylformamidase catalyzes the hydrolytic cleavage of the highly stable formamide bond. Sequence analysis of the enzyme suggested that it does not belong to the known family of amidohydrolases. The enzyme in its smallest form, is a tetramer made of two large and two small subunits. It is a very halotolerant enzyme that oligomerizes to form a dimer of tetramers with increasing salt concentration. The domain that contains the active site is a new fold. The active site is a Fe(III) center coordinated by two tyrosines and glutamic acid. Site‐directed mutagenesis shows that glutamic acid, histidine, and asparagine around the active site are critical for the catalysis by the enzyme. The evolution of the enzyme to break down the man‐made dimethylformamide is still a mystery.
Sirohydrochlorin Nickelochelatase
CfbA
Authors: Fujishiro Takashi
Published: March 2022

Sirohydrochlorin nickelochelatase CfbA is one of the coenzyme F430 biosynthetic (Cfb) enzymes. CfbA catalyzes insertion of Ni
2+
into sirohydrochlorin (SHC) to yield nickel‐sirohydrochlorin (Ni‐SHC). From a structural viewpoint, CfbA belongs to the class II chelatase family. In addition, CfbA is regarded as an ‘ancestral’ class II chelatase due to its unique homodimeric architecture, which is structurally homologous to the overall architectures of monomeric ‘descendant’ class II chelatases. Furthermore, two CfbA types, type I/type II, based on its His‐rich/non‐His‐rich motif, have been demonstrated to be important for considering the coevolution of CfbA enzymes and the coenzyme F430 (F430)‐containing archaea. More importantly, some historical aspects are described for not only CfbA enzymes from F430‐containing organisms (e.g.
Methanocaldococcus jannaschii
) but also ancestral class II chelatases, called CbiX
S
, from non‐F430‐containing organisms (e.g.
Archaeoglobus fulgidus
). Herein, there are suggestions: the name of ‘CfbA’ should be used for the ancestral class II chelatases from ‘F430‐containing’ organisms, and the name of ‘CbiX
S
’ should be used for the ancestral class II chelatases from the ‘F430‐lacking’ organisms, because the abbreviation ‘Cfb’ comes from
C
oenzyme
F
430
b
iosynthesis. Not only the classification and annotations but also some unique biochemical and structural properties of CfbA are shown in this review. In particular, a unique catalytic mechanism of CfbA, a substrate‐SHC‐assisted Ni‐insertion mechanism, is introduced, which has been demonstrated based on the successful X‐ray crystal structural analysis of an intermediate of the CfbA ternary complex with Ni
2+
and SHC. Some studies of CfbA with nonnatural substrates are also shown, which possibly provide evolutionary aspects and substrate specificities of the class II chelatases.
Copper‐Containing Nitrite Reductase
Authors: Rose Samuel L , Hough Michael A , Antonyuk Svetlana V , Eady Robert R , Hasnain S. Samar
Published: March 2022

Cu‐containing nitrite reductases (CuNiRs) catalyze the reduction of nitrite to nitric oxide and water. CuNiRs are part of the denitrification and nitrification pathways that are not only important from bioenergetics perspective but are also the major contributors to terrestrial and oceanic nitrogen cycling. These pathways make a significantly increasing contribution to global warming by release of N
2
O, an ozone‐depleting and greenhouse gas some 300‐fold more potent than CO
2
. Advanced crystallographic techniques based on synchrotrons and X‐ray free electron lasers have been applied to this important class of enzymes. Here we provide a detailed review of recent results obtained from a global effort.
Synthetic Strategies for the Preparation of Gold‐based Anticancer Agents
Authors: Gukathasan Sailajah , Awuah Samuel G.
Published: March 2022

Gold (Au) complexes attained an exceptional reach as new metal‐based anticancer agents in recent years. The FDA‐approved AuIcomplex auranofin [(2,3,4,6‐tetra‐O‐acetyl‐1‐thio‐β‐d‐glucopyranose (triethylphosphoranylidene)gold(I)] displays efficacious chemotherapeutic potential in phase I and II clinical trials for both liquid and solid tumors. Ignited by the success of auranofin as an anticancer agent, new designs and synthetic processes toward AuIand AuIIIcomplexes for unique biomedical applications are actively ongoing. In the past few years, AuIIIcomplexes have become attractive as premised on promising antitumor preclinical studies despite bottlenecks associated with stability and biological target identification. Advancement of gold complexes to the clinic will require agents with improved anticancer potency, unambiguous biological target, pharmacokinetic profile, and optimal stability. Thus, ligand tuning and innovative synthetic chemistry coupled with rigorous biological characterization are crucial. In this article, an overview of known synthetic strategies for the synthesis of gold anticancer complexes is presented. Primary focus on the synthesis of AuIand AuIIIcomplexes along with anticancer outcomes is outlined. This article presents medicinal inorganic chemists with an armory of synthetic tools and purification protocols to readily access highly potent gold anticancer agents.
Influence of expert degree and scientific validity of testimony on mock Jurors' perceptions of credibility
Authors: Flick Cassandra , Smith Olivia K. H. , Schweitzer Kimberly
Published: March 2022

Expert credentials and scientific validity of expert evidence have been shown to impact mock jurors' perceptions of expert credibility. The current study investigated the interactive effects of these two variables. Participants (N = 273) were exposed to a mock civil trial based on a real hostile work environment case. We were interested in both the interactions of expert degree and overall validity of the evidence, as well the impact of degree with specific types of validity. In a between‐subjects design, we varied the expert's educational degree (MS vs. PhD) and the scientific validity of the expert's evidence through internal validity (high vs. low) and ecological validity (high vs. low). Results indicated an interaction of degree with overall scientific quality, while controlling for participant sex. When the expert presented high‐quality testimony, a PhD expert and their evidence were perceived more positively than an MS expert.
Kernel center adaptation in the reproducing kernel Hilbert space embedding method
Authors: Paruchuri Sai Tej , Guo Jia , Kurdila Andrew
Published: March 2022

The performance of adaptive estimators that employ embedding in reproducing kernel Hilbert spaces (RKHS) depends on the choice of the location of basis kernel centers. Parameter convergence and error approximation rates depend on where and how the kernel centers are distributed in the state‐space. In this article, we develop the theory that relates parameter convergence and approximation rates to the position of kernel centers. We develop criteria for choosing kernel centers in a specific class of systems by exploiting the fact that the state trajectory regularly visits the neighborhood of the positive limit set. Two algorithms, based on centroidal Voronoi tessellations and Kohonen self‐organizing maps, are derived to choose kernel centers in the RKHS embedding method. Finally, we implement these methods on two practical examples and test their effectiveness.
Microstructural Evolution of a Selective Laser Melted FeCoCrNiMn–(N,Si) High‐Entropy Alloy Subject to Cold‐Rolling and Subsequent Annealing
Authors: Zhang Zhonglun , Wu Yufan , Gu Ji , Song Min
Published: March 2022

Herein this article, selective laser melting (SLM) technique is used to manufacture N and Si contained FeCoCrNiMn high‐entropy alloy (HEA). The SLMed FeCoCrNiMn–(N,Si) alloy is then treated by cold‐rolling and isochronous annealing. The influences of Si and N additions on the microstructural evolution and tensile properties of the HEA are investigated. It is shown that adding Si and N elements increases the recrystallization temperature and postpones the whole recrystallization processing of the alloy. The annealing‐induced anomalous hardening is seen for the alloy at both 500 and 600 °C. When the annealing treatment temperature is 800 °C and above, the alloy is fully recrystallized in 1 h. The tensile properties evolution of the FeCoCrNiMn–(N,Si) alloy with annealing temperature has the similar tendency to the equiatomic FeCoCrNiMn alloy. In addition, uniformly distributed Cr2N particles form during the annealing processing. The dispersion and small size of the Cr2N particles significantly improve the tensile mechanical properties of the alloy by inhibiting the movements of both dislocations and grain boundaries.
Phase Modulation Enabled High Thermoelectric Performance in Polycrystalline GeSe0.75Te0.25
Authors: Wang Zhiran , Wu Hong , Zhang Bin , Dai Lu , Huo Yufeng , Huang Yuling , Han Guang , Lu Xu , Zhou Xiaoyuan , Wang Guoyu
Published: March 2022

The structure–property link is inherent to materials. Hexagonal Ge4Se3Te phase, with special Ge–Ge cationic bonding and distinctive from other IV–VI compounds, reveals thermoelectric (TE) performance far below the common values for IV–VI compounds. Here, it is shown that its TE performance can be substantially enhanced by phase modulation: increasing sintering temperature from 573 to 773 K leads to the decomposition of hexagonal phase into a composite of orthorhombic and rhombohedral phases, which significantly improves TE performance at T ≤ 550 K; Sb/Cd doping stabilizes the rhombohedral phase, compensates the hole concentration, and strengthens the phonon scattering, which further enhances the TE performance over the whole temperature range. The theoretical calculation reveals that the rhombohedral phase has a more favorable electronic band structure than the hexagonal phase for achieving higher electrical transport properties. The optimized TE performance is obtained in rhombohedral Ge0.90Sb0.08Cd0.02Se0.75Te0.25, with a zTmax of 1.36 at 778 K and zTave of 0.73 from 322 to 778 K, which are among the highest values in the Se‐rich side of Ge(Se, Te) system, and one order higher than those in the hexagonal phase. The study sheds light on the validity of phase modulation for TE performance optimization in Ge(Se, Te)‐based material systems.
Anion‐Doping‐Induced Vacancy Engineering of Cobalt Sulfoselenide for Boosting Electromagnetic Wave Absorption
Authors: Liu Jiaolong , Zhang Limin , Wu Hongjing
Published: March 2022

Vacancy engineering is an attractive approach to modulate the electronic structure of transition metal chalcogens. However, illustrating how anion vacancy can be engineered to tailor their electromagnetic (EM) parameters and electromagnetic wave (EMW) absorption, based on clear vacancy concentrations and/or various anion vacancies rather than semiempirical rules, is currently lacking but significantly desired. An anion‐doping‐induced vacancy engineering is pioneered, where the selective oxidation process upgrades the transformation from Co‐based precursor to S‐doped CoSe2 (System II) instead of Se‐doped CoS2 (System I) in the subsequent sulfuration/selenization, which results in vacancy level improvement and coexistence of sulfur vacancies (VS) and selenium vacancy (VSe). Thanks to the boosted dielectric polarization loss provided by the comparable coexistence of sulfur/selenium vacancies (VS/VSe = 0.52), S‐doped CoSe2 harvests a broad bandwidth of 9.25 GHz (8.75–18.00 GHz) at 2.42 mm. This feature almost simultaneously achieves 100% coverage for X‐, and Ku‐bands, outperforming all reported metal sulfides/selenides until now. This work establishes a clear correlation between vacancy concentrations/various anion vacancies and EMW dissipation ability, offering valuable insights for designing advanced EMW absorbing materials.
Porous Cationic Electrospun Fibers with Sufficient Adsorption Sites for Effective and Continuous 99TcO4− Uptake
Authors: Zhao Rui , Chen Dingyang , Gao Nvwa , Yuan Liyong , Hu Wei , Cui Fengchao , Tian Yuyang , Shi Weiqun , Ma Shengqian , Zhu Guangshan
Published: March 2022

Removal of radioactive technetium‐99 (99TcO4−) from water by effective adsorbents is highly desired but remains a challenge. The currently used resin adsorbents possess several obstacles, such as slow adsorption kinetics and low adsorption capacity. To address these issues, herein a type of fibrous adsorbent with porosity and hyper‐branched quaternary ammonium groups, namely porous cationic electrospun fibers (PCE fibers), is successfully prepared. PCE fibers can remove 97% of 99TcO4− within 1 min and the equilibrium time of 99% removal is 20 min. The predicted maximum adsorption capacity toward the surrogate ReO4− can reach 826 mg g−1, which is higher than the state of art anion‐exchange resins and most of the other reported adsorbents. Furthermore, PCE fibers have good selectivity for ReO4− in the presence of competitive anions, and can retain ReO4− uptake under extreme conditions including high acid–base and gamma irradiation. Importantly, PCE fibrous adsorptive membrane is employed for dynamic ReO4− removal from simulated Hanford LAW stream with a processing capacity of 600 kg simulated stream per kilogram PCE fibers. The excellent performance highlights the advantages of PCE fibers over traditional resins in technetium removal.
Isogenous Asymmetric–Symmetric Acceptors Enable Efficient Ternary Organic Solar Cells with Thin and 300 nm Thick Active Layers Simultaneously
Authors: Bai Hai‐Rui , An Qiaoshi , Jiang Mengyun , Ryu Hwa Sook , Yang Jie , Zhou Xue‐Jiao , Zhi Hong‐Fu , Yang Can , Li Xiong , Woo Han Young , Wang Jin‐Liang
Published: March 2022

Integrating desirable light absorption, energy levels, and morphology in one matrix is always the aspiration to construct high‐performance organic solar cells (OSCs). Herein, an asymmetric acceptor Y6‐1O is incorporated into the binary blends of acceptor Y7‐BO and donor PM6 to prepare ternary OSCs. Two isogenous asymmetric–symmetric acceptors with similar chemical skeletons tend to form alloy‐like state in blends due to their good compatibility, which contributes to optimizing the morphology for efficient charge generation and extraction. The complementary absorption of two acceptors helps to improve the photon harvesting of ternary blends, and the higher lowest unoccupied molecular orbital (LUMO) energy level of Y6‐1O offers the chance to uplift the mixed LUMO energy levels of acceptors. Combining the aforesaid benefits, the ternary OSCs with 10 wt% Y6‐1O produce a top‐ranked power conversion efficiency (PCE) of 18.11% with simultaneously elevated short‐circuit current density, open‐circuit voltage, and fill factor in comparison to Y7‐BO‐based binary devices. Furthermore, the optimized ternary OSCs with ≈300 nm active layers obtain a champion PCE of 16.61%, which is the highest value for thick‐film devices reported so far. This work puts forward an avenue for further boosting the performance of OSCs with two isogenous acceptors but different asymmetric structures.
Perspective of 2D Integrated Electronic Circuits: Scientific Pipe Dream or Disruptive Technology?
Authors: Waltl Michael , Knobloch Theresia , Tselios Konstantinos , Filipovic Lado , Stampfer Bernhard , Hernandez Yoanlys , Waldhör Dominic , Illarionov Yury , Kaczer Ben , Grasser Tibor
Published: March 2022

Within the last decade, considerable efforts have been devoted to fabricating transistors utilizing 2D semiconductors. Also, small circuits consisting of a few transistors have been demonstrated, including inverters, ring oscillators, and static random access memory cells. However, for industrial applications, both time‐zero and time‐dependent variability in the performance of the transistors appear critical. While time‐zero variability is primarily related to immature processing, time‐dependent drifts are dominated by charge trapping at defects located at the channel/insulator interface and in the insulator itself, which can substantially degrade the stability of circuits. At the current state of the art, 2D transistors typically exhibit a few orders of magnitude higher trap densities than silicon devices, which considerably increases their time‐dependent variability, resulting in stability and yield issues. Here, the stability of currently available 2D electronics is carefully evaluated using circuit simulations to determine the impact of transistor‐related issues on the overall circuit performance. The results suggest that while the performance parameters of transistors based on certain material combinations are already getting close to being competitive with Si technologies, a reduction in variability and defect densities is required. Overall, the criteria for parameter variability serve as guidance for evaluating the future development of 2D technologies.
Flexible Mo2C‐Modified SiC/C Nanofibers for BroadBand Electromagnetic Wave Absorption
Authors: Yuan Xiaoyan , Li Huanhuan , Sha Aiming , Huang Shengyan , Li Bo , Guo Shouwu
Published: March 2022

Materials with 1D structure exhibit a remarkable advantage for losing electromagnetic (EM) wave energy. Herein, flexible Mo2C‐modified SiC/C nanofibers (Mo‐SiC/C NFs) are synthesized for the first time by co‐electrospinning and subsequent high‐temperature pyrolysis, using polycarbosilane (PCS) and molybdenum acetyl acetone (MoO2(acac)2) as precursors. It is found that the polymer derived temperature of PCS is significantly decreased by introducing MoO2(acac)2, as well as endowing the SiC/C NFs with good flexibility, high crystallinity, and remarkable microwave absorption performance. The as‐prepared fibers dispersed in paraffin with a low filler loading (15 wt%) exhibit a minimum reflection loss (RL, dB) of ‐62.5 dB, and a wide effective absorption bandwidth (EAB, RL<‐10 dB) of 6.8 GHz at 2.75 mm. Meanwhile, the EAB of the hybrid can cover the whole X‐band and most of the C‐band by modulating its thickness. These high‐efficient performances mainly originate from the specific 1D microstructure, abundant interfaces and defects, and synergistic effect among SiC, Mo2C, and C matrix. Thus, this work offers a way to explore flexible SiC/C NFs as a promising candidate with lightweight and wide EAB for EM wave absorption.
Oligonucleotic Probes and Immunosensors Based on Nanoporous Anodic Alumina for Screening of Diseases
Authors: Xifre‐Perez Elisabet , Ferre‐Borrull Josep , Marsal Lluis F.
Published: March 2022

This paper is an overview of the recent advances in nanoporous anodic alumina sensing platforms based on the interaction of oligonucleotides and antibodies with bioelements (e.g., virus, bacteria, or biomarkers) that can cause or identify diseases. Nanoporous alumina is the common platform material for all these sensing devices that have an enormous potential for the next‐generation bioanalytical systems. Nanoporous alumina is a cost‐effective material with morphological flexibility that provides high sensitivity to the sensing systems due to its large surface‐to‐volume ratio. Immunosensors transduce the signal produced by the specific antibody–antigen interaction. They are widely used for clinical analysis due to the high selectivity and sensitivity of their immunoreaction, transduced by different methods (electrochemical, optical, piezoelectric, etc). Another important, outstanding and more recently type of biosensors are based on the oligonucleotic functionalization of nanoporous alumina. Oligonucleotides can bind to a wide variety of elements (small organic molecules, proteins, or cells) with high selectivity, specificity, and affinity, even higher to those of antibodies. The basic concepts and mechanisms of their sensing methods for health care biosensing are introduced. Their transduction methods and great potential applications will be evaluated and classified in detail, together with a discussion of possible future trends.
Shaping Electromagnetic Fields with Irregular Metasurface
Authors: Li Zhenfei , Liu Ji , Zhang Jin , Shao Linda , Zhang Chiben , Wang Xiong , Jin Ronghong , Zhu Weiren
Published: March 2022

The electromagnetic scattering of an object is directly related to its physical geometry and material properties. While metasurfaces show excellent performances in mimicking material properties almost at well by flexibly designing meta‐atoms with arbitrary electromagnetic responses, their physical geometries are generally in a regular manner. The break of a metasurface's geometry will inevitably affect its electromagnetic scattering that introduces uncertainty in wavefront manipulation. Here, a general approach for highly efficient wavefront manipulation with irregular shaped metasurfaces is proposed. Such an approach establishes a universal iterative modulation relation between the metasurface and scattered field by introducing boundary constraints at the aperture, enabling to deal with the electromagnetic scattering from a metasurface with arbitrary spatial shape. In this way, the desired wavefront form can be engineered using meta‐atom sequences with arbitrarily shaped aperture. As a proof of concept, a flower‐shaped metasurface operating in the reflection mode is designed and experimentally demonstrated for reconstructing four random focuses with uniform and high‐efficiency intensity distribution at near‐field region, while the flower shaped field pattern can be extracted near the aperture plane. Such a method may pave a new route for advanced wavefront manipulation and electromagnetic concealment/camouflage applications.
Direct GaAs Nanowire Growth and Monolithic Light‐Emitting Diode Fabrication on Flexible Plastic Substrates
Authors: Khayrudinov Vladislav , Sorokina Anastasiia , Raj Vidur , Gagrani Nikita , Koskinen Tomi , Jiang Hua , Tittonen Ilkka , Jagadish Chennupati , Hoe Tan Hark , Lipsanen Harri , Haggren Tuomas
Published: March 2022

The growth of self‐catalyzed GaAs nanowires (NWs) and monolithic light‐emitting diode (LED) directly on flexible plastic substrates is reported. Dense GaAs NW forest is attained in self‐catalyzed mode using metalorganic vapor phase epitaxy. The NWs are shown to be crystalline with a zinc‐blende phase. The optical properties of the GaAs NWs are found to be promising in both photoluminescence emission and light‐trapping based on reflectance and transmittance measurements. The LED is fabricated from p‐type NWs by depositing Au as Ohmic contact and TiO2/ITO as an electron‐selective contact. The demonstrated NW growth and LED fabrication represent a significant step toward low‐cost, industrially feasible flexible III–V NW optoelectronic applications, as plastic is inexpensive, and the fabrication steps are compatible with roll‐to‐roll processing.
Gold(I)‐Catalyzed Domino Reaction: An Access to Furooxepines
Authors: Galéa Roméric , Blond Gaëlle
Published: March 2022

Abstract. We report herein the synthesis of [7,5]‐fused bicyclic acetals, also named furooxepines through a gold(I)‐catalyzed domino reaction. During this transformation, two molecules of homopropargyl alcohol react together, in a sequence including an intramolecular hydroalkoxylation, condensation, a 1,6‐enyne cycloisomerization, acetalization and an isomerization. This gold(I)‐catalyzed domino reaction allow the formation of three bonds, two heterocycles and a tetrasubstituted carbon stereocenters in a one‐step operation with 100% atom economy. Post‐functionalizations allow the formation of tetrahydrofurans.

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Antioxidant and Biocompatible CO2‐Based Biocomposites from Vegetable Wastes for Active Food Packaging
Authors: Tran Thi Nga , Lim Kwon Taek , Fiorentini Fabrizio , Athanassiou Athanassia
Published: March 2022

In this study, an innovative and scalable strategy is developed to valorize vegetable wastes as valuable and cost‐effective natural antioxidant resources in the development of CO2‐based biocomposites. The dried vegetable stems (parsley and spinach) are firstly micronized and then incorporated into a CO2‐derived poly(propylene carbonate) (PPC) polymer matrix by hot compression molding technique. The vegetable waste microparticles are found to be homogenously dispersed within the PPC matrix. Due to the establishment of a strong intermolecular hydrogen bond network between PPC and vegetable waste microparticles, the obtained biocomposites exhibit improved mechanical properties compared to pure PPC, comparable to these of common plastics use for packaging materials. The water barrier properties of the developed biocomposites are also promising for packaging applications. Additionally, the developed biocomposites are found to be biocompatible and show effective antioxidant scavenging activity against 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical cation (ABTS•+). Therefore, these antioxidant and biocompatible biocomposites deriving from CO2 greenhouse gas and industrial agro‐food wastes are of great interest for active food packaging applications.
An Injectable Dual‐Function Hydrogel Protects Against Myocardial Ischemia/Reperfusion Injury by Modulating ROS/NO Disequilibrium
Authors: Hao Tian , Qian Meng , Zhang Yating , Liu Qi , Midgley Adam C. , Liu Yangping , Che Yongzhe , Hou Jingli , Zhao Qiang
Published: March 2022

Acute myocardial infarction (MI) is the leading cause of death worldwide. Exogenous delivery of nitric oxide (NO) to the infarcted myocardium has proven to be an effective strategy for treating MI due to the multiple physiological functions of NO. However, reperfusion of blood flow to the ischemic tissues is accompanied by the overproduction of toxic reactive oxygen species (ROS), which can further exacerbate tissue damage and compromise the therapeutic efficacy. Here, an injectable hydrogel is synthesized from the chitosan modified by boronate‐protected diazeniumdiolate (CS‐B‐NO) that can release NO in response to ROS stimulation and thereby modulate ROS/NO disequilibrium after ischemia/reperfusion (I/R) injury. Furthermore, administration of CS‐B‐NO efficiently attenuated cardiac damage and adverse cardiac remodeling, promoted repair of the heart, and ameliorated cardiac function, unlike a hydrogel that only released NO, in a mouse model of myocardial I/R injury. Mechanistically, regulation of the ROS/NO balance activated the antioxidant defense system and protected against oxidative stress induced by I/R injury via adaptive regulation of the Nrf2‐Keap1 pathway. Inflammation is then reduced by inhibition of the activation of NF‐κB signaling. Collectively, these results show that this dual‐function hydrogel may be a promising candidate for the protection of tissues and organs after I/R injury.
Fiber‐Optic Theranostics (FOT): Interstitial Fiber‐Optic Needles for Cancer Sensing and Therapy
Authors: Ran Yang , Xu Zhiyuan , Chen Minfeng , Wang Wei , Wu Yang , Cai Jiexuan , Long Junqiu , Chen Zhe‐Sheng , Zhang Dongmei , Guan Bai‐Ou
Published: March 2022

Photonics has spurred a myriad of diagnostic and therapeutic applications for defeating cancer owing to its superiority in spatiotemporal maneuverability and minimal harm. The limits of light penetration depth and elusiveness of photosensitizer utilization, however, impede the implementation of the photodiagnostic and ‐therapy for determining and annihilating the deep‐situated tumor. Herein, a promising strategy that harnesses functional optical fibers is developed and demonstrated to realize an in vivo endoscopic cancer sensing and therapy ensemble. Tumor detection is investigated using hypoxia‐sensitive fluorescent fibers to realize fast and accurate tumor recognition and diagnosis. The tumor treatment is further performed by exploiting the endogenous photothermal effect of rare‐earth‐doped optical fibers. The eradication of orthotopic and subcutaneous xenografts significantly validates the availability of tumoricidal fibers. The strategy opens horizons to inspire the design of optical fiber‐mediated “plug and play” precise tumor theranostics with high safety, which may intrigue broader fields, such as fiber optics, materials, chemistry, medicine, and clinics.
Gestational Leucylation Suppresses Embryonic T‐Box Transcription Factor 5 Signal and Causes Congenital Heart Disease
Authors: Zhang Xuan , Liu Lian , Chen Wei‐Cheng , Wang Feng , Cheng Yi‐Rong , Liu Yi‐Meng , Lai Yang‐Fan , Zhang Rui‐Jia , Qiao Ya‐Nan , Yuan Yi‐Yuan , Lin Yan , Xu Wei , Cao Jing , Gui Yong‐Hao , Zhao Jian‐Yuan
Published: March 2022

Dysregulated maternal nutrition, such as vitamin deficiencies and excessive levels of glucose and fatty acids, increases the risk for congenital heart disease (CHD) in the offspring. However, the association between maternal amino‐acid levels and CHD is unclear. Here, it is shown that increased leucine levels in maternal plasma during the first trimester are associated with elevated CHD risk in the offspring. High levels of maternal leucine increase embryonic lysine‐leucylation (K‐Leu), which is catalyzed by leucyl‐tRNA synthetase (LARS). LARS preferentially binds to and catalyzes K‐Leu modification of lysine 339 within T‐box transcription factor TBX5, whereas SIRT3 removes K‐Leu from TBX5. Reversible leucylation retains TBX5 in the cytoplasm and inhibits its transcriptional activity. Increasing embryonic K‐Leu levels in high‐leucine‐diet fed or Sirt3 knockout mice causes CHD in the offspring. Targeting K‐Leu using the leucine analogue leucinol can inhibit LARS activity, reverse TBX5 K‐Leu modification, and decrease the occurrence of CHD in high‐leucine‐diet fed mice. This study reveals that increased maternal leucine levels increases CHD risk in the offspring through inhibition of embryonic TBX5 signaling, indicating that leucylation exerts teratogenic effects during heart development and may be an intervening target of CHD.
Oxygen‐Deficient Metal Oxides for Supercapacitive Energy Storage: From Theoretical Calculation to Structural Regulation and Utilization
Authors: Wan Yi , Li Yanan , Wang Kai , Liu Haiyan , Hu Han , Wu Mingbo
Published: March 2022

Nanostructured metal oxides (MOs) have been a well‐concerning focus for the development of high‐performance supercapacitors due to their capability of delivering pseudocapacitive contribution. To effectively promote the potential of MOs for this purpose, the regulation of their electronic configuration, electrical conductivity, and active sites should be conducted where the introduction of oxygen vacancies (OVs) into MOs offers promising prospects. As a result, a comprehensive summary of the latest progress in this field is of paramount importance. After theoretically analyzing the role of OVs for boosted supercapacitive energy storage performance at the molecular/atomic levels, the possibility of controllably engineering OVs in MOs is discussed to provide valuable guides for experimental design. Then, the continuously emerged technologies for regulating OVs in MOs are classified in a simple yet clear manner, namely, direct incorporation and postregulation. Then, the typical examples of the oxygen‐deficient MOs including single transition MOs, binary transition MOs, and composites with improved electrochemical performance have been discussed. Finally, the challenges and prospects of this rising field are outlooked to conclude this review.
Artificial intelligence informed toxicity screening of amine chemistries used in the synthesis of hybrid organic–inorganic perovskites
Authors: Su An , Cheng Yingying , Xue Haotian , She Yuanbin , Rajan Krishna
Published: March 2022

This article describes a machine learning guided framework for screening the potential toxicity impact of amine chemistries used in the synthesis of hybrid organic–inorganic perovskites. Using a combination of a probabilistic molecular fingerprint technique that encodes bond connectivity (MinHash) coupled to non‐linear data dimensionality reduction methods (Uniform Manifold Approximation and Projection), we develop an “Amine Atlas.” We show how the Amine Atlas can be used to rapidly screen the relative toxicity levels of amine molecules used in the synthesis of 2D and 3D perovskites and help identify safer alternatives. Our work also serves as a framework for rapidly identifying molecular similarity guided, structure–function relationships for safer materials chemistries that also incorporate sustainability/toxicity concerns.