bluuebunny/crossref_metadata_2025 huggingface dataset:
A behavioral reverse correlation technique to decipher early auditory feature coding
Authors: Kaernbach Christian
Published: July 2002

Certainly people do not perceive auditory stimuli as a bunch of time-varying spectral components, but what else could provide a format for early auditory feature coding? This question has been dealt with extensively in vision, revealing sensitivity to waveletlike stimuli and to simple object feature elements. Up to now there has been no attempt to decipher the alphabet of hearing at a coding level higher than that of sinusoidal phonons on the auditory nerve. The present study demonstrates a behavioral reverse correlation technique revealing which kind of features will be detected in random stimuli (noise). When a noise segment is repeatedly presented, it will elicit simple percepts, equivalent to the detection of lines, circles, or faces in random dot images. When these percepts are masked by another noise segment, in about 60% of the cases there is a clear-cut difference of masking level depending on the sign of the masker. By adding up sign-sensitive maskers in the correct polarity, one gets the ‘‘noison’’ that elicits this specific percept. The noisons presented in the talk represent only a random selection of possible auditory features, but they give an indication of the potential scope of feature specifications.
Airbus airframe noise reduction—A European harmonized research effort
Authors: Dobrzynski Werner
Published: July 2002

Very large aircraft—such as the planned Airbus A3XX—require correspondingly high lift forces and extended landing gear structures, thus causing potentially very high airframe noise levels during the landing approach. This problem was realized by the Airbus Consortium, and the first relevant research initiatives date back to the early 1990s. Soon after, initial research at DLR began under contract to Airbus Industrie, dedicated to landing gear airframe noise. Recognizing the general challenge of research for aircraft noise reduction at that time, a European Noise Reduction Initiative (ENRI) was proposed, dealing with both engine and airframe noise. Subsequent technical discussions, however, led to separate programs for engine and airframe noise research, the latter being initiated under the acronym RAIN (reduction of airframe and installation noise). RAIN encompasses analytical and experimental work to describe, predict, and reduce the noise both from landing gears and high lift devices. In parallel, national research programs began: In France wind tunnel and flyover experiments relate to the whole aircraft airframe noise characteristics, while corresponding research in Germany focuses on high lift devices noise. In Great Britain, noise modeling is performed for landing gear noise prediction. These national efforts are coordinated by the Airbus partner companies (3E-program).
The effects of signal duration on NoSo and NoSπ thresholds at 500 Hz and 4 kHz
Authors: Bernstein Leslie R. , Trahiotis Constantine
Published: July 2002

A two-interval, two-alternative temporal forced-choice procedure was used to measure NoSo and NoSπ masked thresholds with 500-Hz and 4-kHz tonal signals. The duration of the signal was either 10, 20, 40, or 320 ms. The maskers were 200-Hz-wide bands of Gaussian noise centered at the frequency of the signal and presented continuously. Decreasing the duration of the 500-Hz tonal signal resulted in a modest increase (1.5 dB or so) in the masking-level difference (MLD) measured between NoSo and NoSπ conditions. In contrast, decreasing the duration of the 4-kHz tonal signal resulted in a substantial decrease (4.5 dB or so) in the MLD. Comparisons of the data with thresholds predicted from analyses based on “windows of temporal integration” provided quantitatively acceptable accounts of the data. The data obtained in the NoSπ condition at 4 kHz, which are novel and were of primary interest, were well-accounted for in a statistical sense. However, there were small, but systematic, discrepancies between the predictions and the data. Those discrepancies, although small in magnitude, suggest that binaural temporal integration at high frequencies, where the envelopes of the stimuli convey the information, may be inherently different from both monaural temporal integration and binaural temporal integration at low frequencies.
Photoacoustic detection and localization of small gas leaks
Authors: Yönak Serdar H. , Dowling David R.
Published: July 2002

Leak detection and localization are critical manufacturing quality-control processes. Many industrial and domestic machines use or convey pressurized gases or liquids. Unintended leaks from machine components may be detrimental to consumers, manufacturers, and the environment. This paper describes a leak detection technique based on photoacoustic sounds produced by the interaction of a carbon dioxide (CO2) laser tuned to 10.6 micrometers and a photoactive tracer gas, sulfur hexaflouride (SF6), emitted by calibrated leak sources. Acoustic signals generated by a high-speed scan of the laser beam through the cloud of tracer gas formed near the leak are recorded in a bandwidth from 3 to 52 kHz by multiple microphones. From the recorded signals, the presence or absence of a leak may be deduced by comparison with the background noise level at the signal frequencies, which occur at the harmonics of the scan rate. When a leak is present, its location is determined from a simple model of the acoustic environment and matched field processing (MFP). Current results show that a gas leak of 1 cm3 per day can be detected and localized to within ±3 mm in a few seconds using four microphones, placed 0.41 m from the leak location, and an incoherent average of the MFP ambiguity surfaces at eight signal frequencies. Comparisons of the Bartlett and minimum-variance-distortionless matched field processors are also presented.
Extension of the angular spectrum approach to curved radiators
Authors: Wu Ping , Stepinski Tadeusz
Published: July 2002

The angular spectrum approach (ASA) is conventionally applied to the evaluation of acoustic fields from planar radiators because it is usually based on the 2-D Fourier transform (or the zero-order Hankel transform in the axisymmetrical case) which is implemented only in a plane. The present paper is intended to extend the ASA to more general cases where radiators have curved surfaces. For this purpose, two approaches are developed. The first one is the extended ASA and is derived in a general way. From this approach, the angular spectrum of a curved radiator is given by a double integral that does not take the 2-D Fourier transform form, and thus cannot be implemented using 2-D fast Fourier transform (FFT) but by numerical integration. The second approach is the indirect ASA that gives the angular spectrum via 2-D Fourier transforming an initial field pre-calculated in a plane. The method for calculating the initial field is proposed based on the method developed by Ocheltree and Frizzell for planar sources. An example is given of a linear array with a cylindrically concave surface, and in this case, the angular spectrum (the double integral) from the extended ASA reduces to a single integral. The angular spectra of the array are calculated using both approaches and compared. The comparison has shown that the angular spectra obtained from both approaches are in excellent agreement. The accuracy and efficiency of the two approaches are studied in the numerical implementation. In this example, the extended ASA has been shown to be more efficient and more accurate than the latter approach. Both approaches can be applied to arbitrarily curved transducers. In the general case where the double integral cannot be reduced to a single integral, the latter approach can be more efficient.
Acoustic scintillations and angle-of-arrival fluctuations observed outdoors with a large planar vertical microphone array
Authors: Wilson D. Keith , Tate Calandra R. , Swanson David C. , Reichard Karl M.
Published: July 2002

A vertical planar array of 32 microphones (eight elements in the vertical direction and four in the horizontal; overall dimensions approximately 6 m by 3 m) was used to image the scintillations and angle-of-arrival fluctuations from a source 770 m distant. Data sets of 20-min duration were collected in a variety atmospheric conditions. On a windy afternoon, the source image underwent dramatic scintillations and fluctuations in its apparent position. For still nighttime conditions, the image was much more stable, although deep fading still occurred.
Full-field mapping of ultrasonic field by light-source-synchronized projection
Authors: Yao Gang , Wang Lihong V.
Published: July 2002

A simple method for imaging ultrasonic fields in clear media is introduced. A modulated laser source is used to project the ultrasonic field onto a CCD camera. By use of the source-synchronized lock-in detection scheme, 2D images of the amplitude and phase distributions can be determined simultaneously. This technique is experimentally demonstrated with a 1-MHz and a 3.5-MHz ultrasonic transducer operated in continuous-wave mode. This method is very straightforward to implement and can be combined with the traditional tomographic reconstruction technique to obtain the 3D distribution of an ultrasonic field.
A composite model of the auditory periphery for simulating responses to complex sounds
Authors: Robert Arnaud , Eriksson Jan L.
Published: July 2002

This paper presents a phenomenological model of the cochlea. It consists of a bank of nonlinear time-varying parallel filters and an active distributed feedback. Realistic filter shapes are obtained with the all-pole gamma-tone filter (APGF), which provides both a good approximation of the far more complex wave propagation or cochlear mechanics models and a very simple implementation. Special care has been taken in modeling nonlinear properties in order to mimic the responses of the cochlea to complex stimuli. As a result, the model reproduces several observed phenomena including compression, two-tone suppression, and suppression of tones by noise. The distributed feedback, based on physiological evidence from outer hair cell (OHC) functioning, controls the damping parameter of the APGF and provides good modeling of both low-side and high-side suppression. Responses to more complex stimuli as well as a study of the model’s parameters are also presented. Areas of application of this type of model include understanding of signal coding in the cochlea and auditory nerve, development of hearing aids, speech analysis, as well as input to neural models of higher auditory centers.
Direct imaging of traveling Lamb waves in plates using photorefractive dynamic holography
Authors: Telschow K. L. , Deason V. A. , Schley R. S. , Watson S. M.
Published: July 2002

Anisotropic stiffness properties of sheet materials can be determined by measuring the propagation of Lamb waves in different directions, but this typically requires multiple positioning of a suitable transducer at several points or scanning over the area of the sample plate. A laser imaging approach is presented that utilizes the adaptive property of photorefractive materials to produce a real-time measurement of the antisymmetric Lamb traveling wave displacement and phase in all planar directions simultaneously without scanning. Continuous excitation and lock-in methodology is employed, enabling the data to be recorded and displayed by a video camera. Analysis of the image produces a direct quantitative determination of the phase velocity in all directions showing plate stiffness anisotropy in the plane. The method is applicable to materials that scatter light diffusely and provides quantitative imaging of the dynamic surface motion exhibited by traveling elastic waves. A description is given of this imaging process and, for the first time, its ability to perform lock-in measurement of elastic wave displacement amplitude and phase.
Measuring the threshold for speech reception by adaptive variation of the signal bandwidth. II. Hearing-impaired listeners
Authors: Noordhoek Ingrid M. , Houtgast Tammo , Festen Joost M.
Published: July 2002

In a previous study [Noordhoek et al., J. Acoust. Soc. Am. 105, 2895–2902 ], an adaptive test was developed to determine the speech-reception bandwidth threshold (SRBT), i.e., the width of a speech band around 1 kHz required for a 50% intelligibility score. In this test, the band-filtered speech is presented in complementary bandstop-filtered noise. In the present study, the performance of 34 hearing-impaired listeners was measured on this SRBT test and on more common SRT (speech-reception threshold) tests, namely the SRT in quiet, the standard SRT in noise (standard speech spectrum), and the spectrally adapted SRT in noise (fitted to the individual’s dynamic range). The aim was to investigate to what extent the performance on these tests could be explained simply from audibility, as estimated with the SII (speech intelligibility index) model, or require the assumption of suprathreshold deficits. For most listeners, an elevated SRT in quiet or an elevated standard SRT in noise could be explained on the basis of audibility. For the spectrally adapted SRT in noise, and especially for the SRBT, the data of most listeners could not be explained from audibility, suggesting that the effects of suprathreshold deficits may be present. Possibly, such a deficit is an increased downward spread of masking.
Forward masking in normal-hearing, hearing-impaired, and noise-masked normal listeners
Authors: Henry Paula P. , Grantham D. Wesley
Published: July 2002

This study examined forward-masking functions in normal-hearing, hearing-impaired, and noise-masked normal listeners using a 300-ms, one-octave 80 dB SPL masker centered at 4000 Hz and a 20-ms, 4000-Hz pure-tone signal. Thresholds were measured as a function of interstimulus interval (0 to 150 ms), and a time constant (τ) was estimated from the best exponential fit to this function. No significant differences were found between τ values obtained from the normal-hearing (mean: 44 ms) and hearing-impaired (mean: 45 ms) subjects. Thus, temporal resolution in this task was not worse for the impaired listeners than for the normal listeners. Under the noise-masked condition, normal-hearing subjects completed the forward-masking task in the presence of a continuous 4000-Hz, one-octave noise, whose level was chosen to shift each subject’s threshold to match that of a hearing-impaired subject of equivalent age and gender. The mean τ value obtained in the noise-masked condition was 8 ms, which was significantly smaller than the τ values obtained from either group in the absence of a background masker. This curious finding suggests that use of a continuous noise masker to simulate hearing loss is not effective in this temporal resolution task. [Work supported by NIDCD.]
Combustion instabilities in propulsion systems
Authors: Yang Vigor
Published: July 2002

Periodic acoustic motions in combustion chambers, a phenomenon commonly known as combustion instability, were discovered in air-breathing and rocket engines at about the same time in the late 1930s. Since then, unstable oscillations have occurred in most, if not practically all, new development programs. Indeed, because of the high density of energy release in volume having relatively low losses, conditions normally favor excitation and sustenance of oscillations in any combustion chamber intended for a propulsion system. This presentation will provide an overview of combustion instabilities in three types of propulsion systems (i.e., solid rocket motors, liquid rocket engines, and air-breathing engines), with emphasis focused on the state-of-the-art understanding and future research needs. Various research issues in acoustics, fluid mechanics, and chemistry related to oscillatory combustion in practical systems will be discussed. Both passive and active control techniques will be covered. In particular, the application of contemporary CFD schemes, approximate analytical methods, and experimental diagnostic tools to combustion instability studies will be addressed in detail.
Influence of source and echo separation on echo threshold of natural complex sounds
Authors: Valenzuela Miriam N. , Hafter Ervin R.
Published: July 2002

Most studies of the precedence effect are based on stimuli that differ dramatically from ‘‘realistic’’ stimuli. Important differences include the following. (a) Stimulus types used in studies are often clicks, noise bursts or sinusoids; realistic sounds are mostly harmonic or inharmonic complex tones. (b) Durations of stimuli used in studies often avoid a temporal overlap between lead and lag; durations of realistic sounds are normally such that first and subsequent wave fronts overlap most of the time. (c) Lead and lag stimuli used in studies to simulate a primary sound and its reflection from a nearby surface are often signals of equal amplitude and identical wave form; reflections of realistic sounds differ normally from the primary sound in amplitude and wave form. As a first step toward understanding the precedence effect and its significance in ‘‘real world’’ situations, experiments with synthetic piano tones of durations longer than 100 ms (longer than echo delays in typical rooms) were conducted in a simulated reverberant environment. The dependence of echo threshold on the direction of sound incidence was studied using measurements of fusion and localization dominance. The results show a decrease of echo threshold with an increase of spatial separation between primary source and reflection.
Power flow in coupled bending and longitudinal waves in beams
Authors: Szwerc Richard P. , Burroughs Courtney B. , Hambric Stephen A. , McDevitt Timothy E.
Published: July 2002

In complex structures, curvature and impedance discontinuities (e.g., junctions) couple bending and longitudinal waves. Propagation losses for longitudinal waves are often much less than losses for bending waves, and damping treatments often less effective on longitudinal waves. When the dissipation in longitudinal waves is less than that on bending waves, longitudinal waves can provide an efficient means of power flow between bending waves generated at one location and bending waves that are a source of acoustic radiation at another location. In order to design and locate effective treatments, knowledge of the power flow in longitudinal as well as bending waves is required. The measurement of power in both bending and longitudinal waves when both waves are present is demonstrated. Measurements conducted on a straight beam and a T-beam are compared to predictions obtained using finite element methods. The effect of coupling between waves at the junction in a T-beam is illustrated using results from measurements of power flow.
Coupled mode perturbation theory of range dependence
Authors: Tindle C. T. , O’Driscoll L. M. , Higham C. J.
Published: July 2002

The conventional coupled mode solution is combined with perturbation theory to give a fast, accurate range-dependent normal mode solution for deep water acoustic propagation. Perturbation theory is used to calculate the new normal modes at each range step. The new modes are obtained as a linear combination of the modes for the previous step without requiring a numerical solution of the depth-separated wave equation. The process may be repeated for many steps and yields normal modes and eigenvalues which are sufficiently accurate for solution of practical problems in deep water. The method is applied to long-range propagation through oceanic fronts.
The Forced Vibrating Reed: Error Analysis
Authors: Glauz R. D.
Published: July 2002

A linearized error analysis is performed of the forced vibrating reed test. The test variables measured are amplitude ratio, phase lag, and frequency in addition to geometric variables. Utilizing the perturbations of the complex modulus resulting from perturbations of the measured quantities enables the experimenter to design effective tests for maximum utilization of test equipment.
Rheological Properties of Dilute Polymer Solutions Determined in Extensional and in Shearing Experiments
Authors: Baid K. M. , Metzner A. B.
Published: July 2002

Rheogoniometric and fiber spinning experiments were carried out using polyacrylamide solutions containing 100, 200, and 300 ppm of polymer. The stress levels in the extensional flow experiments were 1–3 orders of magnitude greater than those which would have been exhibited by Newtonian fluids of identical viscosity level. Since the stresses arising in extensional flows of simple fluids are very sensitive to the distant deformation history of the material,whereas the recent history is of dominant importance in shearing flows, the ability to model both deformation processes with a common constitutive equation is a very severe test of the latter, and one which is of importance in a variety of processing areas. An evaluation of several constitutive relations is presented; two derivative models are found to portray the results with reasonable accuracy, although a given set of material parameters does not suffice for predicting all of the stresses measured in both shearing and extension.
Effect of Polymer Additives on the Process of Transition
Authors: Sharma R. S. , Seshadri V. , Malhotra R. C.
Published: July 2002

The process of transition from laminar to turbulent flow on a flat plate in the presence of drag-reducing polymer additives has been investigated. In particular, the effect of polymer concentration and plate inclination on the formation of turbulent spots and their subsequent growth has been studied. It is observed that polymer addition causes a delay in both onset of turbulence and complete transition. The turbulent spots are seen to move at a lower velocity in the presence of the polymer additives. Further, the pressure gradient affects the transition in polymer solutions in the same way that it does in pure water.
Simple shearing flow of three-dimensional foams and highly concentrated emulsions with planar films
Authors: Reinelt Douglas A.
Published: July 2002

Simple shearing flow of a ‘‘dry,’’ perfectly ordered, three-dimensional foam composed of planar films is considered. The undeformed spatially periodic cell structure is formed by regular tetrakaidecahedra, which have six square surfaces and eight regular hexagonal surfaces. The elastic–plastic response of the foam is modeled by assuming that all surfaces remain planar and that the angle between connected surfaces does not change during elastic deformation. An explicit expression for the stress tensor that is valid up to the elastic limit is determined. Past the elastic limit, the foam structure and macroscopic stress are piecewise continuous functions of strain. Discontinuities in structure and stress are associated with topological (T1) changes in the film network structure that occur when the area of an individual film vanishes. These T1 changes, which reduce surface energy and result in the switching of cell neighbors, are essential mechanisms for yield behavior in foam flow. The foam structure is determined for all values of shear strain by choosing initial cell orientations that lead to periodic behavior with strain. The shear stress evaluated from a strain energy method differs from that obtained by volume averaging the local surface tension forces; this inconsistency arises because a foam with planar films cannot satisfy the equilibrium requirement that three films meet at equal angles of 120°.
Bulk crosslinking of diallyl phthalate monomers
Authors: Heydel C. , Cassagnau P. , Michel A.
Published: July 2002

The radical crosslinking of ortho diallyl phthalate was studied with dynamic mechanical analysis and infrared spectroscopy, the combination of which provides an in situ method for the elucidation of the effects of the reaction temperature. Studies of the side reactions (degradative transfer) showed that the reaction temperature must be lower than 170 °C to obtain the optimal mechanical properties when dicumyl peroxide is used as a initiator. Above 170 °C, at the end of polymerization, the extent of reaction increases with the reaction temperature, whereas the crosslinking density decreases. These phenomena can be explained by an intramolecular cyclization reaction which consumes the allyl bond without formation of a crosslinking point. Furthermore, the gel point behavior was well characterized from the divergence of zero shear rate viscosity and the power law in dynamic moduli. The value of the relaxation exponent (Δ=0.75) was found to be close to the theoretical percolation t value. However, the exponent increases slightly with the reaction temperature, suggesting a more open network structure. This phenomenon was also explained by an intramolecular reaction that evolves as a function of temperature.
Association of Demographic and Socioeconomic Indicators With the Use of Wearable Devices Among Children
Authors: Kim Ethan H. , Jenness Jessica L. , Miller Adam Bryant , Halabi Ramzi , de Zambotti Massimiliano , Bagot Kara S. , Baker Fiona C. , Pratap Abhishek
Published: March 2023

Importance

The use of consumer-grade wearable devices for collecting data for biomedical research may be associated with social determinants of health (SDoHs) linked to people’s understanding of and willingness to join and remain engaged in remote health studies.

Objective

To examine whether demographic and socioeconomic indicators are associated with willingness to join a wearable device study and adherence to wearable data collection in children.

Design, Setting, and Participants

This cohort study used wearable device usage data collected from 10 414 participants (aged 11-13 years) at the year-2 follow-up (2018-2020) of the ongoing Adolescent Brain and Cognitive Development (ABCD) Study, performed at 21 sites across the United States. Data were analyzed from November 2021 to July 2022.

Main Outcomes and Measures

The 2 primary outcomes were (1) participant retention in the wearable device substudy and (2) total device wear time during the 21-day observation period. Associations between the primary end points and sociodemographic and economic indicators were examined.

Results

The mean (SD) age of the 10 414 participants was 12.00 (0.72) years, with 5444 (52.3%) male participants. Overall, 1424 participants (13.7%) were Black; 2048 (19.7%), Hispanic; and 5615 (53.9%) White. Substantial differences were observed between the cohort that participated and shared wearable device data (wearable device cohort [WDC]; 7424 participants [71.3%]) compared with those who did not participate or share data (no wearable device cohort [NWDC]; 2900 participants [28.7%]). Black children were significantly underrepresented (−59%) in the WDC (847 [11.4%]) compared with the NWDC (577 [19.3%]; P < .001). In contrast, White children were overrepresented (+132%) in the WDC (4301 [57.9%]) vs the NWDC (1314 [43.9%]; P < .001). Children from low-income households (<$24 999) were significantly underrepresented in WDC (638 [8.6%]) compared with NWDC (492 [16.5%]; P < .001). Overall, Black children were retained for a substantially shorter duration (16 days; 95% CI, 14-17 days) compared with White children (21 days; 95% CI, 21-21 days; P < .001) in the wearable device substudy. In addition, total device wear time during the observation was notably different between Black vs White children (β = −43.00 hours; 95% CI, −55.11 to −30.88 hours; P < .001).

Conclusions and Relevance

In this cohort study, large-scale wearable device data collected from children showed considerable differences between White and Black children in terms of enrollment and daily wear time. While wearable devices provide an opportunity for real-time, high-frequency contextual monitoring of individuals’ health, future studies should account for and address considerable representational bias in wearable data collection associated with demographic and SDoH factors.
Are We Undertreating Pain—A Review of the CDC 2022 Opioid Prescription Guidelines in the Context of Otolaryngology
Authors: Xu Katherine , Sangal Neel R. , Chao Tiffany N.
Published: March 2023

This Viewpoint discusses the 2022 Centers for Disease Control and Prevention guidelines for opioid prescription in the context of otolaryngology.
Hunting and Foraging, Central Africa
Authors: Lupo Karen
Published: March 2023

The prehistoric record of foragers in Central Africa is very limited. It is generally agreed that ancestors of ethnographically known forest foragers (formerly called pygmies) were present in forested areas of Central Africa by 70,000 years ago, if not earlier. Limited data from a handful of well‐dated archaeological sites show that these were likely mobile populations that exploited resources from forest and savanna woodlands. Historic and ethnohistoric records provide the most detailed records of forest foragers. These observations and later ethnographic studies show that forest foragers were nomadic populations that specialized in exploiting forest resources. Many of these populations had well‐established and multidimensional interrelationships with settled Bantu‐speaking food producers. The most visible aspect of these interrelationships was the economic exchange of forest products for domesticated foods. But the interrelationships also had important ritual, political, and social dimensions.
Western Gaṅgas
Authors: Adiga Malini
Published: March 2023

The Western Gaṅgas are among the longest‐reigning dynasties in Karnataka and shaped the history and culture of the region which came to be named Gaṅgavādi after them. Their origin is probably local and by the mid‐sixth century
ce
they had established a hold over the river valleys of the Penner and Kaveri. They claimed overlordship of the chiefs and village heads who they enlisted to serve under them as tax collectors and land demarcators. From the late sixth century the Gaṅgas were drawn into the conflict between the Cāḷukyas and Pallavas, which continued till the mid‐eighth century when the Rāṣṭrakūṭas became the sovereign power of the Deccan. For about thirty years from ca. 788
ce
, the Rāṣṭrakūṭas held Gaṅgavāḍi directly through their governors but after 819
ce
the Gaṅgas regained their kingdom. The relationship with the Rāṣṭrakūṭas seems to have been one of subordinate alliance for the Gaṅgas, particularly under Rācamalla II, Būtuga II, and their successors. The Gaṅga period in southern Karnataka was marked by the spread of agriculture and the growth of a variegated intermediary class comprising chiefs of various lineages,
gāvuṇḍas
, heroes, and temples.
Indo‐Scythians and Śakas
Authors: Skinner Michael C.
Published: March 2023

The Indo‐Scythians and Śakas were nomadic groups who established kingdoms in the regions of Gandhara and northern and western India starting in the first century
bce
. Śakas in Gandhara and northern India continued to rule until the emergence of the Kushana Empire in the second half of the first century
ce
, while those in western India remained in power until the fifth century when they were defeated by the Guptas. Coins and inscriptions are the main sources available for these rulers and this evidence has been used to establish a Śaka chronology and locate the areas they governed. Śaka rulers also initiated dating eras, and the Śaka era started by the Western Kṣatrapa Caṣṭana in 78
ce
is still used in parts of India today.
Bhāskaravarman
Authors: Pal Sayantani
Published: March 2023

Bhāskaravarman was a king in early seventh‐century Kāmarūpa in the Brahmaputra Valley. He belonged to the Bhauma Nāraka dynasty of Assam. Under Bhāskaravarman Kāmarūpa emerged as a strong regional power and became involved in north Indian politics through a friendly alliance with Harṣavardhana.
Shengqi
(Lived Object)
Authors: Hung Wu
Published: March 2023

Shengqi
or “lived objects” are tomb furnishings which were originally owned and used by the dead. This entry discusses the concept and practice of this type of object in its ritual, cultural, and intellectual contexts in ancient China.
Magnetically Enhanced Thin‐Film Coarsening by a Magnetic XPFC Model Allowing to Decouple Magnetic Anisotropy and Magnetostriction
Authors: Backofen Rainer , Voigt Axel
Published: March 2023

External magnetic fields provide a macroscopic control mechanism to influence the microstructure of polycrystalline materials. Herein, the influence of strong magnetic fields on grain growth in thin films is modeled with a magnetic extended phase field crystal model. The magneto–structural effects are incorporated into the correlation function in reciprocal space. With this approach, magnetic anisotropy, magnetostriction, and mobility of grain boundary can be controlled and a variety of geometrical and topological properties consistent with experimental results can be determined.
Spinodal Decomposition of B2‐phase and Formation of Cr‐Rich Nano‐precipitates in AlCoCrFeNi2.1 Eutectic High‐Entropy Alloy
Authors: Charkhchian Javad , Zarei-Hanzaki Abbas , Moshiri Ali , Abedi Hamid Reza , Schwarz Tim M. , Lawitzki Robert , Schmitz Guido , Chadha Kanwal , Aranas Clodualdo , Shen Jiajia , Oliveira João Pedro
Published: March 2023

Herein, the occurrence of a B2‐phase separation and formation of Cr‐rich nano‐precipitates during the solidification process of AlCoCrFeNi2.1 eutectic high‐entropy alloy is addressed. Toward this end, various advanced characterizations, including high‐resolution transmission electron microscopy and atom probe tomography combined with thermodynamic calculations, are employed. The as‐solidified microstructure is composed of face‐centered cubic (FCC) dendrites and interdendritic regions consisting of a eutectic mixture of FCC and body‐centered cubic (BCC) phases. The presence of uniformly distributed Cr‐rich nano‐precipitates is traced through the BCC B2 phase in the interdendritic area. Regarding the occurrence of upward diffusion and Gibbs free energy variation, the formation of Cr‐rich nano‐precipitates is attributed to the spinodal decomposition where the critical temperature of 800 °C is passed behind during the solidification process. The formation of dense dislocation array in the interdendritic region due to thermal stress induced during solidification is introduced as a pathway for diffusion of alloying elements in the course of cooling stage.
Oral Delivery of Protein Drugs via Lysine Polymer‐Based Nanoparticle Platforms
Authors: Han Shuyan , Xin Peikun , Guo Qilun , Cao Zhong , Huang Hai , Wu Jun
Published: March 2023

Oral delivery of proteins has opened a new perspective for the treatment of different diseases. However, advances of oral protein formulation are usually hindered by protein susceptibility and suboptimal absorption in the gastrointestinal tract (GIT). Polymeric nano drug delivery systems are considered revolutionary candidates to solve these issues, which can be preferably tunable against specific delivery challenges. Herein, a tailored family of lysine‐based poly(ester amide)s (Lys‐aaPEAs) is designed as a general oral protein delivery platform for efficient protein loading and protection from degradation. Insulin, as a model protein, can achieve effective internalization by epithelial cells and efficient transport across the intestinal epithelium layer into the systemic circulation, followed by controlled release in physiological environments. After the oral administration of insulin carried by Lys‐aaPEAs with ornamental hyaluronic acid (HA), mice with type 1 diabetes mellitus showed an acceptable hypoglycemic effect with alleviated complications. A successful oral insulin delivery is associated with patient comfort and convenience and simultaneously avoids the risk of hypoglycemia compared with injections, which is of great feasibility for daily diabetes therapy. More importantly, this versatile Lys‐aaPEAs polymeric library can be recognized as a universal vehicle for oral biomacromolecule delivery, providing more possibilities for treating various diseases.
Consumer demand for food at home and food away from home: Understanding economic linkages during the pandemic
Authors: Balagtas Joseph V. , Cooper Joseph , McLaughlin Patrick , Qin Fei
Published: March 2023

Household food expenditure has shifted away from Food at Home (FAH) and towards Food Away from Home (FAFH). Prior to the COVID‐19 pandemic, FAFH's share of food expenditure surpassed that of FAH, reaching 55% in 2019. Yet economic research on FAFH and the interaction of FAFH and FAH has been limited. Combining scanner data for meat sales in grocery stores with data for FAFH expenditure, we estimate a model of demand for at‐home meat, incorporating FAFH expenditure as a demand shifter. We quantify substitution between FAFH expenditure and FAH meat and quantify the impact of the COVID‐19 disruptions to the food service sector on retail prices of FAH meat.
Explainable Artificial Intelligence Approach to Identify the Origin of Phonon‐Assisted Emission in WSe2 Monolayer
Authors: Yoo Jaekak , Cho Youngwoo , Jeong Byeonggeun , Choi Soo Ho , Kim Ki Kang , Lim Seong Chu , Lee Seung Mi , Choo Jaegul , Jeong Mun Seok
Published: March 2023

The application of explainable artificial intelligence in nanomaterial research has emerged in the past few years, which has facilitated the discovery of novel physical findings. However, a fundamental question arises concerning the physical insights presented by deep neural networks; the model interpretation results have not been carefully evaluated. Herein, explainable artificial intelligence and quantum mechanical calculations is bridged to investigate the correlation between light scattering and emission in a WSe2 monolayer. Convolutional neural networks using light scattering and emission data are first trained, while expecting the networks to determine the relationships between them. The trained models are interpreted and the specific phonon contribution during the exciton relaxation process is derived. Finally, the findings are independently evaluated through quantum mechanical calculations, such as the Born–Oppenheimer molecular dynamics simulation and density functional perturbation theory. The study provides reliable fundamental physical insight by evaluating the results of neural networks and suggests a novel methodology that can be applied in materials science.
Brønstedsäure‐Katalyse – Kontrolle der Konkurrenz zwischen monomerem und dimerem Reaktionsweg erhöht Stereoselektivität
Authors: Franta Maximilian , Gramüller Johannes , Dullinger Philipp , Kaltenberger Simon , Horinek Dominik , Gschwind Ruth M.
Published: March 2023

Chirale Phosphorsäuren (CPS) sind inzwischen ein bevorzugter Katalysatortyp in der Organokatalyse, jedoch bleibt die Auswahl der optimalen Katalysatorstruktur weiterhin eine Herausforderung. Zusätzlich können unbekannte konkurrierende Reaktionswege die maximale Stereoselektivität und das Potenzial von Vorhersagemodellen einschränken. Bei der CPS‐katalysierten Transferhydrierung von Iminen haben wir für viele Systeme zwei Reaktionswege mit inverser Stereoselektivität gefunden, bei denen entweder eine monomere CPS oder ein Wasserstoffbrücken‐verknüpftes Dimer als Katalysator fungiert. NMR‐Messungen und DFT‐Berechnungen offenbarten ein dimeres Intermediat mit einer stärkeren Substrataktivierung durch Kooperativitätseffekte. Beide Wege können separiert werden: Niedrige Temperaturen und hohe Katalysatoranteile begünstigen den dimeren Reaktionsweg (ee bis zu −98 %), während niedrige Temperaturen und reduzierte Katalysatoranteil den monomeren Reaktionsweg fördern und zu einem signifikant verbesserten ee führen (92–99 % ee; vorher 68–86 % bei höheren Temperaturen). Insgesamt wird eine große Auswirkung auf die CPS‐Katalyse in Bezug auf Reaktionsoptimierung und Vorhersage erwartet.
Terminal Alkynes as One‐Carbon Donors in [5+1] Heteroannulation: Synthesis of Pyridines via Ynimine Intermediates and Application in the Total Synthesis of Anibamine B
Authors: Lavernhe Rémi , Wang Qian , Zhu Jieping
Published: March 2023

Transition‐metal‐catalyzed [4+2] heteroannulation of α,β‐unsaturated oximes and their derivatives with alkynes has been developed into a powerful strategy for the synthesis of pyridines. It nevertheless lacks regioselectivity when unsymmetrically substituted alkynes are used. We report herein the unprecedented synthesis of polysubstituted pyridines by a formal [5+1] heteroannulation of two readily accessible building blocks. A copper‐catalyzed aza‐Sonogashira cross‐coupling between β,γ‐unsaturated oxime esters and terminal alkynes affords ynimines, which, without isolation, undergo an acid‐catalyzed domino reaction involving ketenimine formation, 6π‐electrocyclization and aromatization to afford pyridines. Terminal alkynes served as a one‐carbon donor to the pyridine core in this transformation. Di‐ through pentasubstituted pyridines are accessible with complete regioselectivity and excellent functional‐group compatibility. The first total synthesis of anibamine B, an indolizinium alkaloid with potent antiplasmodial activity, was accomplished featuring this reaction as a key step.
Nickel‐Catalyzed Chemoselective Arylation of Amino Alcohols
Authors: Morrison Kathleen M. , Yeung Charles S. , Stradiotto Mark
Published: March 2023

A systematic evaluation of competitive bisphosphine/Ni‐catalyzed C−N versus C−O cross‐couplings involving model compounds enabled development of hitherto unknown chemoselective O‐ and N‐arylation of amino alcohols with (hetero)aryl chloride electrophiles, without recourse to protection group chemistry. Use of the CyPAd‐DalPhos pre‐catalyst C2 enabled particularly challenging O‐arylation chemoselectivity in amino alcohols featuring branched primary and secondary alkylamine groups, while selective N‐arylation was observed in substrates featuring less‐hindered linear alkylamine and aniline reacting groups. Useful reaction scope in the (hetero)aryl chloride was achieved throughout, and the ability to conduct such transformations using benchtop handling of materials is demonstrated.
Tough, Reprocessable, and Recyclable Dynamic Covalent Polymers with Ultrastable Long‐Lived Room‐Temperature Phosphorescence
Authors: Zhao Zi‐Han , Zhao Pei‐Chen , Chen Shi‐Yi , Zheng You‐Xuan , Zuo Jing‐Lin , Li Cheng‐Hui
Published: March 2023

Room‐temperature phosphorescence (RTP) polymers, whose emission can persist for a long period after photoexcitation, are of great importance for practical applications. Herein, dynamic covalent boronic ester linkages with internal B−N coordination are incorporated into a commercial epoxy matrix. The reversible dissociation of B−N bonds upon loading provides an efficient energy dissipation pathway for the epoxy network, while the rigid epoxy matrix can inhibit the quenching of triplet excitons in boronic esters. The obtained polymers exhibit enhanced mechanical toughness (12.26 MJ m−3), ultralong RTP (τ=540.4 ms), and shape memory behavior. Notably, there is no apparent decrease in the RTP property upon prolonged immersion in various solvents because the networks are robust. Moreover, the dynamic bonds endow the polymers with superior reprocessablity and recyclability. These novel properties have led to their potential application for information encryption and anti‐counterfeiting.
“First Come, First Served” and Threshold Effects in a Central‐to‐Planar‐to‐Helical Hierarchical Chiral Induction
Authors: Zhao Ting , Yi Jigao , Liu Chunhong , Liang Xiaotong , Shen Yanling , Wei Lingling , Xie Xiangyu , Wu Wanhua , Yang Cheng
Published: March 2023

Perylene diimide tethered pillar[5]arene derivatives form aggregates in non‐polar organic solvents, and the complexation of cationic amino acid ethyl ester (cAA‐OEt) with the aggregates induce a central‐to‐planar‐to‐helical chirality transfer, leading to intensive circular dichroism (CD) signals having dissymmetric factors (gabs) of up to 3.67×10−2. The hierarchical chiral induction exhibited an intriguing threshold dose effect, namely, the chiral induction does not occur in the low concentration range of cAA‐OEt but is triggered when cAA‐OEt exceeds a threshold concentration. The inhibited interconversion between the Rp and Sp conformers of pillar[5]arene, which is further restricted in the aggregation, plays a crucial role in the threshold effect. When adding enantiopure cAA‐OEt first to the threshold concentration and then adding an equal amount of the antipodal cAA‐OEt to give cAA‐OEt in racemic form, CD spectra having the same sign as the CD induced by first adding pure cAA‐OEt were induced, thus showing an unprecedented “first come, first served” effect.
Synthesis, spectroscopic characterization, density functional theory, molecular docking studies, antioxidant and antimicrobial potential of novel Schiff base macrocyclic complexes of bivalent manganese
Authors: Mamta  , Pinki  , Subhash  , Chaudhary Ashu
Published: March 2023

The threat of antibiotic resistance to public health is becoming a major cause of mortality on a worldwide scale. It has stimulated the interest of researchers in the development of novel antibiotics. Therefore, a new series of Schiff base macrocyclic ligands (N8MacL1‐N8MacL3) and their bivalent manganese complexes were synthesized and analyzed for biological activities. Characterization of the synthesized macrocyclic compounds was done by various spectroscopic techniques like elemental analysis, infrared (IR), proton nuclear magnetic resonance (NMR), 13C NMR, ultraviolet–visible, mass, electron paramagnetic resonance (EPR), and powder X‐ray diffraction (PXRD). Based on spectral studies, an octahedral environment has been proposed around the manganese metal center in the synthesized macrocyclic complexes. Density functional theory (DFT) calculations were used to evaluate the stability and the electronic properties of the synthesized macrocyclic ligands and their Mn (II) complexes. The structures of the synthesized compounds were optimized by using the def2‐SVP basis set at B3LYP level. The synthesized compounds were evaluated against gram‐positive bacterial strains (Staphylococcus aureus and Bacillus cereus), gram‐negative bacterial strains (Escherichia coli and Xanthomonas campestris), and fungal strains (Candida albicans and Fusarium oxysporum) for their antimicrobial activity by agar well diffusion method. Among all of the newly synthesized compounds, the macrocyclic complex [Mn(N8MacL3)Cl2] exhibited high antimicrobial activity against all bacterial and fungal strains except S. aureus. The virtual screening of synthesized Schiff base ligand [L], macrocyclic ligands (N8MacL1‐N8MacL3), and their Mn (II) complex [Mn(N8MacL1)Cl2‐Mn(N8MacL3)Cl2] are performed against the receptors, which were used for in vitro antimicrobial testing, to identify the most plausible drug–ligand interactions. The scavenging activity of DPPH radicals was utilized to study the antioxidant activity of the synthesized compounds. The macrocyclic metal complex [Mn(N8MacL3)Cl2] exhibited excellent antioxidant activity.
Accelerated Workflow for Antiperovskite‐based Solid State Electrolytes
Authors: Sjølin Benjamin H. , Jørgensen Peter B. , Fedrigucci Andrea , Vegge Tejs , Bhowmik Arghya , Castelli Ivano E.
Published: March 2023

We developed and implemented a multi‐target multi‐fidelity workflow to explore the chemical space of antiperovskite materials with general formula X3BA (X=Li, Na, Mg) and Pm‐3m space group, searching for stable high‐performance solid state electrolytes for all‐solid state batteries. The workflow is based on the calculation of thermodynamic and kinetic properties, including phase and electrochemical stability, semiconducting behavior, and ionic diffusivity. To accelerate calculation of the kinetic properties, we use a surrogate model to predict the transition state structure during ionic diffusion. This reduces the calculation cost by more than one order of magnitude while keeping the mean error within 73 meV of the more accurate nudged elastic band method. This method identifies 14 materials that agree with the experimentally reported results as some of the best solid state electrolytes. Moreover, this approach is general and chemistry neutral, so can be applied to other battery chemistries and crystal prototypes.