bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy and variability assessment of a semiautomatic technique for segmentation of the carotid arteries from three‐dimensional ultrasound images
Authors: Gill J. D. , Ladak H. M. , Steinman D. A. , Fenster A.
Published: July 2002

In this paper, we report on a semiautomatic method for segmentation of three‐dimensional (3D) carotid vascular ultrasound (US) images. Our method is based on a dynamic balloon model represented by a triangulated mesh. The mesh is manually placed within the interior of the carotid vessels, then is driven outward until it reaches the vessel wall by applying an inflation force to the mesh. Once the mesh is in close proximity to the vessel wall, it is further deformed using an image‐based force, in order to better localize the boundary. Since the method requires manual initialization, there is inherent variability in the position and shape of the final segmented boundary. Using a 3D US image of a patient's carotids, we have examined the local variability in boundary position as the initialization position is varied throughout the interior of the carotid vessels in the 3D image. We have compared the semiautomatic segmentation method to a fully manual segmentation method, and found that the semiautomatic approach is less variable than the intraobserver variability for manual segmentation. We have furthermore examined the accuracy of the semiautomatic method by comparing the average surface to an “ideal” surface, determined by the average manually segmented surface. We have found, in general, good agreement between the semiautomatic and manual segmentation methods. For the 3D US image in question, the mean separation between the average segmented surface and the gold standard was found to be 0.35 mm. The two surfaces were determined to agree with each other, within uncertainty, at 65% of the mesh points comprising the two surfaces.
Measurement of the ratio h/e2 in an advanced undergraduate laboratory
Authors: Schober A. M. , Ruedlinger B. , Dahm A. J.
Published: July 2002

The two-dimensional integer quantum Hall effect is shown to be a feasible experiment for an advanced undergraduate laboratory. A measurement of the ratio h/e2 yielded a value of 25 811(±1+4) Ω. The established value is 25 812.81 Ω. Techniques which would improve this accuracy to 15 ppm are suggested.
Phonetically trained models for speaker recognition
Authors: Rodrı́guez-Liñares Leandro , Garcı́a-Mateo Carmen
Published: July 2002

In this paper, a speaker recognition system that introduces acoustic information into a Gaussian mixture model (GMM)-based recognizer is presented. This is achieved by using a phonetic classifier during the training phase. The experimental results show that, while maintaining the recognition rate, the decrease in the computational load is between 65% and 80% depending on the number of mixtures of the models.
Asymmetry of masking between noise and iterated rippled noise: Evidence for time-interval processing in the auditory system
Authors: Krumbholz Katrin , Patterson Roy D. , Nobbe Andrea
Published: July 2002

This study describes the masking asymmetry between noise and iterated rippled noise (IRN) as a function of spectral region and the IRN delay. Masking asymmetry refers to the fact that noise masks IRN much more effectively than IRN masks noise, even when the stimuli occupy the same spectral region. Detection thresholds for IRN masked by noise and for noise masked by IRN were measured with an adaptive two-alternative, forced choice (2AFC) procedure with signal level as the adaptive parameter. Masker level was randomly varied within a 10-dB range in order to reduce the salience of loudness as a cue for detection. The stimuli were filtered into frequency bands, 2.2-kHz wide, with lower cutoff frequencies ranging from 0.8 to 6.4 kHz. IRN was generated with 16 iterations and with varying delays. The reciprocal of the delay was 16, 32, 64, or 128 Hz. When the reciprocal of the IRN delay was within the pitch range, i.e., above 30 Hz, there was a substantial masking asymmetry between IRN and noise for all filter cutoff frequencies; threshold for IRN masked by noise was about 10 dB larger than threshold for noise masked by IRN. For the 16-Hz IRN, the masking asymmetry decreased progressively with increasing filter cutoff frequency, from about 9 dB for the lowest cutoff frequency to less than 1 dB for the highest cutoff frequency. This suggests that masking asymmetry may be determined by different cues for delays within and below the pitch range. The fact that masking asymmetry exists for conditions that combine very long IRN delays with very high filter cutoff frequencies means that it is unlikely that models based on the excitation patterns of the stimuli would be successful in explaining the threshold data. A range of time-domain models of auditory processing that focus on the time intervals in phase-locked neural activity patterns is reviewed. Most of these models were successful in accounting for the basic masking asymmetry between IRN and noise for conditions within the pitch range, and one of the models produced an exceptionally good fit to the data.
Dispersion of interface waves in sediments with power-law shear speed profiles. II. Experimental observations and seismo-acoustic inversions
Authors: Chapman David M. F. , Godin Oleg A.
Published: July 2002

The propagation of seismic interface waves is investigated in soft marine sediments in which the density is constant, the shear modulus is small, and the profile of shear speed cs versus depth z is of the power-law form cs(z)=c0zν, in which c0 and ν are constants (0<ν<1). Both the phase speed V and the group speed U of interface waves scale with frequency as fν/(ν−1) and they obey the simple relation U=(1−ν)V. These relations are derived in a simple way using ray theory and the WKB method; a companion paper [O. A. Godin and D. M. F. Chapman, J. Acoust. Soc. Am. 110, 1890 (2001)] rigorously derives the same result from the solutions to the equations of motion. The frequency scaling is shown to exist in experimental data sets of interface wave phase speed and group speed. Approximate analytical formulas for the dispersion relations (phase and group speed versus frequency) enable direct inversion of the profile parameters c0 and ν from the experimental data. In cases for which there is multi-mode dispersion data, the water-sediment density ratio can be determined as well. The theory applies to vertically polarized (P-SV) modes as well as to horizontally polarized (SH) modes (that is, Love waves).
Simplified method to solve sound transmission through structures lined with elastic porous material
Authors: Lee Joon-H. , Kim J. , Kim Han-J.
Published: July 2002

An approximate analysis method is developed to calculate sound transmission through structures lined with porous material. Because the porous material has both the solid phase and fluid phase, three wave components exist in the material, which makes the related analysis very complicated. The main idea in developing the approximate method is very simple: modeling the porous material using only the strongest of the three waves, which in effect idealizes the material as an equivalent fluid. The analysis procedure has to be conducted in two steps. In the first step, sound transmission through a flat double panel with a porous liner of infinite extents, which has the same cross sectional construction as the actual structure, is solved based on the full theory and the strongest wave component is identified. In the second step sound transmission through the actual structure is solved modeling the porous material as an equivalent fluid while using the actual geometry of the structure. The development and validation of the method are discussed in detail. As an application example, the transmission loss through double walled cylindrical shells with a porous core is calculated utilizing the simplified method.
Broadband time-reversing array retrofocusing in noisy environments
Authors: Sabra Karim G. , Khosla Sunny R. , Dowling David R.
Published: July 2002

Acoustic time reversal is a promising technique for spatial and temporal focusing of sound in unknown environments. Acoustic time reversal can be implemented with an array of transducers that listens to a remote sound source and then transmits a time-reversed version of what was heard. In a noisy environment, the performance of such a time-reversing array (TRA) will be degraded because the array will receive and transmit noise, and the intended signal may be masked by ambient noise at the retrofocus location. This article presents formal results for the signal-to-noise ratio at the intended focus (SNRf) for TRAs that receive and send finite-duration broadband signals in noisy environments. When the noise is homogeneous and uncorrelated, and a broadcast power limitation sets the TRA’s electronic amplification, the formal results can be simplified to an algebraic formula that includes the characteristics of the signal, the remote source, the TRA, and the noisy environment. Here, SNRf is found to be proportional to the product of the signal bandwidth and the duration of the signal pulse after propagation through the environment. Using parabolic-equation propagation simulations, the formal results for SNRf are illustrated for a shallow water environment at source-array ranges of 1 to 40 km and bandwidths from several tens of Hz to more than 500 Hz for a signal center frequency of 500 Hz. Shallow-water TRA noise rejection is predicted to be superior to that possible in free space because TRAs successfully exploit multipath-propagation.
Nonlinear analysis of irregular animal vocalizations
Authors: Tokuda Isao , Riede Tobias , Neubauer Jürgen , Owren Michael J. , Herzel Hanspeter
Published: July 2002

Animal vocalizations range from almost periodic vocal-fold vibration to completely atonal turbulent noise. Between these two extremes, a variety of nonlinear dynamics such as limit cycles, subharmonics, biphonation, and chaotic episodes have been recently observed. These observations imply possible functional roles of nonlinear dynamics in animal acoustic communication. Nonlinear dynamics may also provide insight into the degree to which detailed features of vocalizations are under close neural control, as opposed to more directly reflecting biomechanical properties of the vibrating vocal folds themselves. So far, nonlinear dynamical structures of animal voices have been mainly studied with spectrograms. In this study, the deterministic versus stochastic (DVS) prediction technique was used to quantify the amount of nonlinearity in three animal vocalizations: macaque screams, piglet screams, and dog barks. Results showed that in vocalizations with pronounced harmonic components (adult macaque screams, certain piglet screams, and dog barks), deterministic nonlinear prediction was clearly more powerful than stochastic linear prediction. The difference, termed low-dimensional nonlinearity measure (LNM), indicates the presence of a low-dimensional attractor. In highly irregular signals such as juvenile macaque screams, piglet screams, and some dog barks, the detectable amount of nonlinearity was comparatively small. Analyzing 120 samples of dog barks, it was further shown that the harmonic-to-noise ratio (HNR) was positively correlated with LNM. It is concluded that nonlinear analysis is primarily useful in animal vocalizations with strong harmonic components (including subharmonics and biphonation) or low-dimensional chaos.
Effects of age and frequency disparity on gap discrimination
Authors: Lister Jennifer , Besing Joan , Koehnke Janet
Published: July 2002

Temporal discrimination was measured using a gap discrimination paradigm for three groups of listeners with normal hearing: (1) ages 18–30, (2) ages 40–52, and (3) ages 62–74 years. Normal hearing was defined as pure-tone thresholds ⩽25 dB HL from 250 to 6000 Hz and ⩽30 dB HL at 8000 Hz. Silent gaps were placed between 14-octave bands of noise centered at one of six frequencies. The noise band markers were paired so that the center frequency of the leading marker was fixed at 2000 Hz, and the center frequency of the trailing marker varied randomly across experimental runs. Gap duration discrimination was significantly poorer for older listeners than for young and middle-aged listeners, and the performance of the young and middle-aged listeners did not differ significantly. Age group differences were more apparent for the more frequency-disparate stimuli (2000-Hz leading marker followed by a 500-Hz trailing marker) than for the fixed-frequency stimuli (2000-Hz lead and 2000-Hz trail). The gap duration difference limens of the older listeners increased more rapidly with frequency disparity than those of the other listeners. Because age effects were more apparent for the more frequency-disparate conditions, and gap discrimination was not affected by differences in hearing sensitivity among listeners, it is suggested that gap discrimination depends upon temporal mechanisms that deteriorate with age and stimulus complexity but are unaffected by hearing loss.
Error analysis in acoustic elastography. II. Strain estimation and SNR analysis
Authors: Bilgen Mehmet , Insana Michael F.
Published: July 2002

Accurate displacement estimates are required to obtain high-quality strain estimates in elastography. In this paper the strain variance is derived from the statistical properties of the displacement field to define a point signal-to-noise ratio for elastography (SNR0). Displacements caused by compressional forces applied along the axis of the transducer beam are modeled by scaling and shifting the axial reflectivity profile of the tissue. The strain variance is given as a function of essential experimental parameters, such as the amount of tissue compression, echo waveform window length, and the amount of window overlap. SNR0 is defined in terms of applied compression and strain variance and normalized by the input signal-to-noise ratio (SNRi) for echo signals, to formulate the performance metric SNR0/SNRi. This quantity characterizes the noise properties, dynamic range, and sensitivity of strain images based on the spatial resolution requirements. The results indicate that low noise, high sensitivity, and limited dynamic range strain images are obtained for high-frequency bandpass signals when the applied strain is small. For large strains, however, one strategy for low-noise strain imaging employs base-band signals to obtain images with large dynamic range but limited peak sensitivity and noise figure. A better strategy includes companding, which eliminates the average strain in the echo signal before cross-correlation to reduce the dynamic range requirement and increase peak sensitivity for strain estimates.
Short-term temporal integration: Evidence for the influence of peripheral compression
Authors: Oxenham Andrew J. , Moore Brian C. J. , Vickers Deborah A.
Published: July 2002

Thresholds for a 6.5-kHz sinusoidal signal, temporally centered in a 400-ms broadband-noise masker, were measured as a function of signal duration for normally hearing listeners and listeners with cochlear hearing loss over a range of masker levels. For the normally hearing listeners, the slope of the function relating signal threshold to signal duration (integration function) was steeper at medium masker levels than at low or high levels by a factor of nearly 2, for signal durations between 2 and 10 ms, while no significant effect of level was found for signal durations of 20 ms and more. No effect of stimulus level was found for the hearing-impaired listeners at any signal duration. For signal durations greater than 10 ms, consistent with many previous studies, the slope of the integration function was shallower for the hearing-impaired listeners than for the normally hearing listeners. However, for shorter durations, there was no significant difference in slope between the results from the hearing-impaired listeners and those from the normally hearing listeners in the high- and low-level masker conditions. A model incorporating a compressive nonlinearity, representing the effect of basilar-membrane (BM) compression, and a short-term temporal integrator, postulated to be a more central process, can account well for changes in the short-term integration function with level, if it is assumed that the compression is greater at medium levels than at low or high levels by a factor of about 4. This is in reasonable agreement with physiological measurements of BM compression, and with previous psychophysical estimates.
Vocalization as an indicator for disorders in mammals
Authors: Riede Tobias , Tembrock Guenter , Herzel Hanspeter , Brunnberg Leo
Published: July 2002

As in humans, diseases in animals may lead to characteristic changes of the voice. In particular, multiparametric frequency, time analysis, as well as the amount of nonlinear phenomena (frequency jumps, subharmonics, biphonation, chaos) provide information about the well-being of an animal and the progress of a disease. Vocalization of domestic animals (dogs and cats) in a university hospital and of a macaque species in a zoological garden have been recorded. First results show that diseases lead typically to shortened call length and decreasing frequency modulation in the cat. Using narrow-band spectrogram subharmonics, biphonation, frequency jumps, and deterministic chaos are identified during the recuperation process of a cat with craniocerebellar trauma. The same nonlinear phenomena appear in several dogs with dysphonia following exhaustion of the voice and in a Japanese macaque infant with an unidentified systemic disorder. The ratio of nonlinear phenomena during systemic disorders of an animal shows a species-specific pattern. There was an increase mostly of frequency jumps in the macaque infant, of frequency jumps and chaos in the dog, and of chaos and subharmonics in the cat vocalization. [Work supported by NaFoeG, Humboldt-University Berlin.]
Measurements of sound speed in excised tissue over temperatures expected under high-intensity focused ultrasound conditions
Authors: Bloch Susannah H. , Bailey Michael R. , Crum Lawrence A. , Kaczkowski Peter J. , Keilman George W. , Mourad Pierre D.
Published: July 2002

Noninvasive monitoring of high-intensity focused ultrasound (HIFU) treatment by diagnostic ultrasound is currently limited by a poor understanding of the bioacoustic effects of tissue heating. Sound-speed measurement has been proposed as a means of noninvasive thermal mapping. The sound speed in most tissues changes monotonically but nonlinearly with temperature to around 60 °C. Above that temperature, at which the tissue proteins begin to denature, irreversible changes occur in the tissue and its corresponding acoustic properties. Sound-speed data around and above the range in which the tissue ‘‘cooks’’ is a challenge to obtain because of changes in tissue shape, compressibility, and overall dimensions associated with the cooking process. In this research, an apparatus to measure sound speed during a controlled temperature change was used to study the effects of temperature, thermal dose, and thermal dose rate on the speed of sound in various mammalian tissues. The apparatus, potential sources of error, and results will be presented, and implications for forward and inverse HIFU propagation modeling and acoustic remote sensing of HIFU-induced temperature changes will be discussed. [Work supported by DARPA.]
Effects of loop diuretics on the suppression tuning of distortion-product otoacoustic emissions in rabbits
Authors: Martin Glen K. , Jassir David , Stagner Barden B. , Lonsbury-Martin Brenda L.
Published: July 2002

The suppression tuning of distortion-product otoacoustic emissions (DPOAEs) is commonly assumed to measure frequency selectivity, because the dominant features of suppression-tuning curves (STCs) are similar to the principal properties of the neural-tuning curves (NTCs) of single auditory-nerve fibers. In the present study, several common loop diuretics were used to affect the DPOAE-generation process to determine if reversible ototoxicity could adversely modify the characteristics of STCs, in a manner similar to that shown previously for NTCs. Contour plots of DPOAE level in the presence of a series of variable-level suppressor tones were obtained before and after administering diuretic drugs that reversibly reduced or eliminated DPOAEs. Primary-tone pairs were centered at 2.8 or 4 kHz, with L1=L2, or L2<L1. From the resulting plots, STC parameters including tip frequency, threshold at the tip frequency, and Q10 dB measures of tuning were extracted for four suppression criteria of 3, 6, 9, and 12 dB. In the pre-drug nonototoxic state, suppression tuning depended on both primary-tone level (L1,L2), and the relative levels of the primaries (L1−L2), with tuning being sharper for lower- than for higher-level equilevel primaries, and sharpest for offset-level primary tones. Following drug injection, the expected decrease in sharpness of tuning evidenced by changes in Q10 dB as well as the dramatically elevated tip thresholds normally seen for NTCs under similar conditions, were not observed. Overall, Q10 dB increased or decreased more or less randomly, with a slight tendency for STCs to become sharper than prior to drug dosing, for the two highest suppression criteria. The STC-tip frequencies demonstrated significant decreases following diuretic administration that were weakly correlated with the associated decreases in DPOAE amplitude. The most consistent changes in response to the drug-induced reduction in DPOAE level were increases in the STC-tip thresholds. However, these changes were relatively small and rarely exceeded 10 dB. In the absence of notable changes in overall STC shape, a major finding was a change in the effectiveness of suppression following ototoxic insult. However, when the amount of suppression was expressed as a percentage of the DPOAE remaining, the effects of diuretic dosing were often almost completely obscured. Overall, the results demonstrated that when the generation of DPOAEs was interfered with by the introduction of a suppressor tone to produce STCs that resemble NTCs, STCs behaved quite differently following reversible cochlear insult than their previously documented neural counterparts. These findings imply that STCs do not assess the frequency-selective aspects of the cochlear amplification process in a manner similar to NTCs.
Wave scattering on a fractal surface
Authors: Qian Z. W.
Published: July 2002

A generalized Von Koch surface was constructed. On the basis of Freedman’s formulation for wave scattering and by applications of the Lipchitz transform under Hölder conditions in fractals, a demonstration was given that the Hausdorff dimension of the solid-angle discontinuity on the scattering surface is the same as the one of the surface itself, and an expression of the scattering strength of the fractal surface has been given. A comparison with the Schulkin–Shaffer empirical formula for the sound scattering from sea surface proposes that, in this situation, the generalized (continuous) Koch surface seems to degenerate into the (discrete) four-two Cantor sets, only the latter make a contribution to the backscattering.
Nonlinear rheology of hyperbranched polyisobutylene
Authors: Robertson C. G. , Roland C. M. , Puskas J. E.
Published: July 2002

The nonlinear shear rheology of a hyperbranched polyisobutylene (PIB) with narrow molecular weight distribution (Mw/Mn=1.3) was compared to that of a polydisperse (Mw/Mn=2.5) linear PIB. After adjusting the respective measurement temperatures to yield equal shear viscosities, the rheology was found to be quite similar for the two polymers, notwithstanding their markedly different structures. These similarities persisted in capillary extrusion experiments at moderate shear rates, on the compounds reinforced with carbon black. However, at higher shear rates, the linear PIB exhibits a greater elastic response, with consequently larger extrudate swell.
The Character of the Stress-Strain Function for Highly Filled Elastomers
Authors: Farris R. J.
Published: July 2002

The uniaxial stress-strain behavior of highly filled elastomers is examined in terms of a simplified thermodynamic model. Experimental data are presented showing the stress-strain-dilatational behavior at a series of hydrostatic pressures from which the behavior at constant volume can be obtained. Deviations from this constant volume stress-strain state are shown to be dependent upon the rate at which pressure-volume and surface energies are being expended by the material due to the formation and growth of vacuoles. Mathematically and experimentally the behavior is considered to be essentially reversible as experimental data indicates. Therefore, the only forms of energy considered are mechanical, and energy balances are made using only force-deflection, pressure-volume, and surface energies. This method of approach accounts for the energy sinks which reduce the rate at which the material accumulates mechanical energy and indicates what factors govern the stress-strain response.
A Correlation of Normal Stress Data for Polyisobutylene Solutions
Authors: Tanner R. I.
Published: July 2002

A survey of normal stress measurements for polyisobutylene fluids is made. The first normal stress (N1) data are correlated with N1c2/τ2 as a very weak function of concentration (c), molecular weight (M), and shear stress (τ). We also find the second normal stress as about −0.15 of N1. The limitations of this empirical correlation are discussed.
In situ characterization by small angle light scattering of the shear-induced coalescence mechanisms in immiscible polymer blends
Authors: Rusu D. , Peuvrel-Disdier E.
Published: July 2002

This work presents an in situ experimental investigation of the shear-induced coalescence mechanism in low concentration polymer blends (1%–10%). An original sizing method based on small-angle light scattering and optical microscopy were used to determine the evolution of the drop size distributions as a function of time. In order to study the pure coalescence mechanisms, measurements were conducted according to a specific flow protocol. The influences of the shear rate, initial morphology, concentration of the polymer blend and phase inversion on the coalescence kinetics were investigated. The investigated blends are mixtures of polydimethylsiloxane and polyisobutene. The amount of strain, the step-down rate ratio and the concentration squared are identified as relevant parameters to describe the coalescence kinetics. The dependence of the steady state drop sizes on the applied shear rate is well described by a coalescence model considering partially mobile interfaces.
Analysis of Palierne’s emulsion model in the case of viscoelastic interfacial properties
Authors: Jacobs U. , Fahrländer M. , Winterhalter J. , Friedrich Chr.
Published: July 2002

The quantitative understanding of rheological experiments on compatibilized binary polymer blends requires the consideration of viscoelastic interfacial properties. The Palierne model offers these capabilities but a systematic analysis has not been performed yet. Starting from the Palierne model containing a Maxwell ansatz for complex interfacial shear or dilatational moduli and which considers a particle-size distribution function, we find that this model combines parameter and material functions in an ambiguous way. Consequently, a simplified version of the model—frequency-independent interfacial moduli and monomodal particle-size distribution—was introduced. Formulas have been derived for the relaxation times, the form relaxation time, and one additional still longer time which is associated with viscoelastic interfacial properties. We have found a good agreement between the predictions of the model and experimental data as well as the characteristic times in the relaxation time spectrum and the derived time constants for a PS/PMMA blend compatibilized with different amounts of a corresponding symmetric block copolymer. These results reveal that from the rheological point of view, the interface is of almost elastic nature, either shear or dilatational.
Basic principle and performance characteristics of multilayer beam conditioning optics
Authors: Jiang Licai , Al-Mosheky Zaid , Grupido Nick
Published: July 2002

Multilayer optics is one of the widely applied optics for conditioning an X-ray beam in the region of X-ray diffraction. Multilayer optics offers a well-balanced performance. The beam conditioned by a multilayer optic is characterized by low divergence, good spectrum purity, and high intensity. This article will start with a short historical note of the development of X-ray multilayer and a summary on the basic performance characteristics of X-ray multilayer, then move on to the discussion on the design principle of one- and two-dimensional optics. Both parallel beam optics and focusing optics will be addressed. As examples, selected applications of multilayer optics are also briefly discussed. Finally, the main problems associated with the application of multilayer optics are identified and the future developments are discussed.
Endogenous/Exogenous Nanovaccines Synergistically Enhance Dendritic Cell‐Mediated Tumor Immunotherapy
Authors: Zhang Yu , Li Qiang , Ding Meng , Xiu Weijun , Shan Jingyang , Yuwen Lihui , Yang Dongliang , Song Xuejiao , Yang Guangwen , Su Xiaodan , Mou Yongbin , Teng Zhaogang , Dong Heng
Published: February 2023

Traditional dendritic cell (DC)‐mediated immunotherapy is usually suppressed by weak immunogenicity in tumors and generally leads to unsatisfactory outcomes. Synergistic exogenous/endogenous immunogenic activation can provide an alternative strategy for evoking a robust immune response by promoting DC activation. Herein, Ti3C2 MXene‐based nanoplatforms (termed MXP) are prepared with high‐efficiency near‐infrared photothermal conversion and immunocompetent loading capacity to form endogenous/exogenous nanovaccines. Specifically, the immunogenic cell death of tumor cells induced by the photothermal effects of the MXP can generate endogenous danger signals and antigens release to boost vaccination for DC maturation and antigen cross‐presentation. In addition, MXP can deliver model antigen ovalbumin (OVA) and agonists (CpG‐ODN) as an exogenous nanovaccine (MXP@OC), which further enhances DC activation. Importantly, the synergistic strategy of photothermal therapy and DC‐mediated immunotherapy by MXP significantly eradicates tumors and enhances adaptive immunity. Hence, the present work provides a two‐pronged strategy for improving immunogenicity and killing tumor cells to achieve a favorable outcome in tumor patients.
Advances in Gelatin Bioinks to Optimize Bioprinted Cell Functions
Authors: Asim Saad , Tabish Tanveer A. , Liaqat Usman , Ozbolat Ibrahim T. , Rizwan Muhammad
Published: February 2023

Gelatin is a widely utilized bioprinting biomaterial due to its cell‐adhesive and enzymatically cleavable properties, which improve cell adhesion and growth. Gelatin is often covalently cross‐linked to stabilize bioprinted structures, yet the covalently cross‐linked matrix is unable to recapitulate the dynamic microenvironment of the natural extracellular matrix (ECM), thereby limiting the functions of bioprinted cells. To some extent, a double network bioink can provide a more ECM‐mimetic, bioprinted niche for cell growth. More recently, gelatin matrices are being designed using reversible cross‐linking methods that can emulate the dynamic mechanical properties of the ECM. This review analyzes the progress in developing gelatin bioink formulations for 3D cell culture, and critically analyzes the bioprinting and cross‐linking techniques, with a focus on strategies to optimize the functions of bioprinted cells. This review discusses new cross‐linking chemistries that recapitulate the viscoelastic, stress‐relaxing microenvironment of the ECM, and enable advanced cell functions, yet are less explored in engineering the gelatin bioink. Finally, this work presents the perspective on the areas of future research and argues that the next generation of gelatin bioinks should be designed by considering cell–matrix interactions, and bioprinted constructs should be validated against currently established 3D cell culture standards to achieve improved therapeutic outcomes.
A Wafer‐Scale Nanoporous 2D Active Pixel Image Sensor Matrix with High Uniformity, High Sensitivity, and Rapid Switching
Authors: Park Heekyeong , Sen Anamika , Kaniselvan Manasa , AlMutairi AbdulAziz , Bala Arindam , Lee Luke P. , Yoon Youngki , Kim Sunkook
Published: February 2023

2D transition‐metal dichalcogenides (TMDs) have been successfully developed as novel ubiquitous optoelectronics owing to their excellent electrical and optical characteristics. However, active‐matrix image sensors based on TMDs have limitations owing to the difficulty of fabricating large‐area integrated circuitry and achieving high optical sensitivity. Herein, a large‐area uniform, highly sensitive, and robust image sensor matrix with active pixels consisting of nanoporous molybdenum disulfide (MoS2) phototransistors and indium–gallium–zinc oxide (IGZO) switching transistors is reported. Large‐area uniform 4‐inch wafer‐scale bilayer MoS2 films are synthesized by radio‐frequency (RF) magnetron sputtering and sulfurization processes and patterned to be a nanoporous structure consisting of an array of periodic nanopores on the MoS2 surface via block copolymer lithography. Edge exposure on the nanoporous bilayer MoS2 induces the formation of subgap states, which promotes a photogating effect to obtain an exceptionally high photoresponsivity of 5.2 × 104 A W−1. A 4‐inch‐wafer‐scale image mapping is successively achieved using this active‐matrix image sensor by controlling the device sensing and switching states. The high‐performance active‐matrix image sensor is state‐of‐the‐art in 2D material‐based integrated circuitry and pixel image sensor applications.
A phylogenomic analysis of Lonicera and its bearing on the evolution of organ fusion
Authors: Srivastav Mansa , Clement Wendy L. , Landrein Sven , Zhang Jingbo , Howarth Dianella G. , Donoghue Michael J.
Published: February 2023

Premise

The ~140 species of Lonicera are characterized by variously fused leaves, bracteoles, and ovaries, making it a model system for studying the evolution and development of organ fusion. However, previous phylogenetic analyses, based mainly on chloroplast DNA markers, have yielded uncertain and conflicting results. A well‐supported phylogeny of Lonicera will allow us to trace the evolutionary history of organ fusion.

Methods

We inferred the phylogeny of Lonicera using restriction site–associated DNA sequencing (RADSeq), sampling all major clades and 18 of the 23 subsections. This provided the basis for inferring the evolution of five fusion‐related traits.

Results

RADSeq data yielded a well‐resolved and well‐supported phylogeny. The two traditionally recognized subgenera (Periclymenum and Chamaecerasus), three of the four sections (Isoxylosteum, Coeloxylosteum, and Nintooa), and half of the subsections sampled were recovered as monophyletic. However, the large and heterogeneous section Isika was strongly supported as paraphyletic. Nintooa, a clade of ~22 mostly vine‐forming species, including L. japonica, was recovered in a novel position, raising the possibility of cytonuclear discordance. We document the parallel evolution of fused leaves, bracteoles, and ovaries, with rare reversals. Most strikingly, complete cupules, in which four fused bracteoles completely enclose two unfused ovaries, arose at least three times. Surprisingly, these appear to have evolved directly from ancestors with free bracteoles instead of partial cupules.

Conclusions

We provide the most comprehensive and well‐supported phylogeny of Lonicera to date. Our inference of multiple evolutionary shifts in organ fusion provides a solid foundation for in depth developmental and functional analyses.
DHEAS and nutritional status among Sidama, Ngandu, and Aka children: Effects of cortisol and implications for adrenarche
Authors: Helfrecht Courtney , Wang Hui , Dira Samuel J. , DeAvila David , Meehan Courtney L.
Published: February 2023

Objective

Adrenarche, the biological event marked by rising production of dehydroepiandrosterone and its sulfate (DHEAS), may represent a sensitive period in child development, with important implications for adolescence and beyond. Nutritional status, particularly BMI and/or adiposity, has long been hypothesized as a factor in DHEAS production but findings are inconsistent, and few studies have examined this among non‐industrialized societies. In addition, cortisol has not been included in these models. We here evaluate effects of height‐ (HAZ), weight‐ (WAZ), and BMI‐ (BMIZ) for‐age on DHEAS concentrations among Sidama agropastoralist, Ngandu horticulturalist, and Aka hunter‐gatherer children.

Methods

Heights and weights were collected from 206 children aged 2–18 years old. HAZ, WAZ, and BMIZ were calculated using CDC standards. DHEAS and cortisol assays were used to determine biomarker concentrations in hair. Generalized linear modeling was used to examine effects of nutritional status on DHEAS concentrations, as well as cortisol, controlling for age, sex, and population.

Results

Despite the prevalence of low HAZ and WAZ scores, the majority (77%) of children had BMI z‐scores >−2.0 SD. Nutritional status has no significant effect on DHEAS concentrations, controlling for age, sex, and population. Cortisol, however, is a significant predictor of DHEAS concentrations.

Conclusions

Our findings do not support a relationship between nutritional status and DHEAS. Instead, results suggest an important role for stress and ecology in DHEAS concentrations across childhood. Specifically, effects of environment via cortisol may be influential to patterning of DHEAS. Future work should investigate local ecological stressors and their relationship to adrenarche.
RNA methyltransferase BmMettl3 and BmMettl14 in silkworm (Bombyx mori) and the regulation of silkworm embryonic development
Authors: Li Bing , Hu Pei , Huang Zhi‐Hao , Yang Jia‐Yue , Wang Jie , Xie Xiu‐Zhi , Wang Yu‐Han , Li Chen‐Chen , Xu Jia‐Ping
Published: February 2023

N6‐methyladenosine (m6A) is a ubiquitous reversible epigenetic RNA modification that plays an important role in regulating many biological processes, especially embryonic development. However, regulation of m6A methylation during silkworm embryonic development and diapause remains to be investigated. In this study, we analyzed the phylogeny of subunits of methyltransferases BmMettl3 and BmMettl14, and detected the expression patterns of BmMettl3 and BmMettl14 in different tissues and at different developmental stages in silkworm. To investigate the function of m6A on the development of silkworm embryo, we analyzed the m6A/A ratio in diapause and diapause termination eggs. The results showed that BmMettl3 and BmMettl14 were highly expressed in gonads and eggs. Moreover, the expression of BmMettl3 and BmMettl14 and the m6A/A ratio were significantly increased in diapause termination eggs compared with diapause eggs in the early stage of silkworm embryonic development. Furthermore, in BmN cell cycle experiments, the percentage of cells in the S phase increased when lacking BmMettl3 or BmMettl14. This work contributes to understanding the role of m6A methylation during insect embryogenesis and gametogenesis. It also provides a research orientation to further analyze the role of m6A methylation in diapause initiation and termination during insect embryonic development.
Multiple schedules with response interruption and redirection to reduce stereotypy in children with autism spectrum disorder: Generalization and social validity
Authors: Callahan Ashley E. , Sidener Tina M. , DeBar Ruth M. , Deshais Meghan A. , Pane Heather M. , Patil Priya
Published: February 2023

Although response interruption and redirection (RIRD) and multiple schedule arrangements have sometimes been shown to be effective in reducing stereotypy for individuals with autism spectrum disorder (ASD), important questions remain about optimal methods for facilitating generalization and social validity. In the current study, we sought to extend the literature on stereotypy treatment and MSAs in several ways. First, we programmed for generalization by conducting sessions with two exemplars of two different categories of activities (i.e., school work, toy play) and assessing generalization with novel exemplars and activities and during the participant's typical instructional program. Second, we used RIRD instructions that were contextual models of appropriate behavior relevant to each activity. Third, during the free access component of the multiple schedule, we used a child's play tent as a first step toward teaching participants to engage in stereotypy during private free time. For all three participants with ASD, stereotypy decreased quickly and substantially, with reductions generalizing to novel activities and contexts. An extensive social validity assessment with board‐certified behavior analysts indicated high social acceptability of the goals, procedures, and outcomes.
Outcomes with plug‐based versus suture‐based vascular closure device after transfemoral transcatheter aortic valve replacement: A systematic review and meta‐analysis
Authors: Sedhom Ramy , Dang Alexander T. , Elwagdy Amr , Megaly Michael , Elgendy Islam Y. , Zahr Firas , Gafoor Samir , Mamas Mamas , Elbadawi Ayman
Published: February 2023

Background

Studies comparing plug‐based (i.e., MANTA) with suture‐based (i.e., ProStar XL and ProGlide) vascular closure devices (VCDs) for large‐bore access closure after transcatheter aortic valve replacement (TAVR) have yielded mixed results.

Aims

To examine the comparative safety and efficacy of both types of VCDs among TAVR recipients.

Methods

An electronic database search was performed through March 2022 for studies comparing access‐site related vascular complications with plug‐based versus suture‐based VCDs for large‐bore access site closure after transfemoral (TF) TAVR.

Results

Ten studies (2 randomized controlled trials [RCTs] and 8 observational studies) with 3113 patients (MANTA = 1358, ProGlide/ProStar XL = 1755) were included. There was no difference between plug‐based and suture‐based VCD in the incidence of access‐site major vascular complications (3.1% vs. 3.3%, odds ratio [OR]: 0.89; 95% confidence interval [CI]: 0.52−1.53). The incidence of VCD failure was lower in plug‐based VCD (5.2% vs. 7.1%, OR: 0.64; 95% CI: 0.44−0.91). There was a trend toward a higher incidence of unplanned vascular intervention in plug‐based VCD (8.2% vs. 5.9%, OR: 1.35; 95% CI: 0.97−1.89). Length of stay was shorter with MANTA. Subgroup analyses suggested significant interaction based on study designs such that there was higher incidence of access‐site vascular complications and bleeding events with plug‐based versus suture‐based VCD among RCTs.

Conclusion

In patients undergoing TF‐TAVR, large‐bore access site closure with plug‐based VCD was associated with a similar safety profile as suture‐based VCD. However, subgroup analysis showed that plug‐based VCD was associated with higher incidence of vascular and bleeding complications in RCTs.
The impact of chronic total occlusions in patients undergoing transcatheter aortic valve replacement: A systematic review and meta‐analysis
Authors: Will Maximilian , Schwarz Konstantin , Weiss Thomas , Leibundgut Gregor , Lamm Gudrun , Vock Paul , Mascherbauer Julia , Kwok Chun Shing
Published: February 2023

Coronary artery disease (CAD) is frequently encountered in patients evaluated for transcatheter aortic valve replacement (TAVR) due to severe aortic stenosis. The prognostic relevance of chronic total occlusions (CTOs) in this setting is poorly understood. We conducted a search of MEDLINE and EMBASE to identify studies evaluating patients who underwent TAVR and evaluated outcomes depending on the presence of coronary CTOs. Pooled analysis was performed to estimate the rate and risk ratio for mortality. Four studies involving 25,432 patients fulfilled the inclusion criteria. The follow up ranged from in‐hospital outcomes to 8‐years follow‐up. Coronary artery disease was present in 67.8% to 75.5% of patients in 3 studies which reported this variable. The prevalence of CTOs varied between 2% and 12.6% in this cohort. The presence of CTOs was associated with increase in length of stay (8.1 ± 8.2 vs. 5.9 ± 6.5, p < 0.01), cardiogenic shock (5.1% vs. 1.7%, p < 0.01), acute myocardial infarction (5.8% vs. 2.8%, p = 0.02) and acute kidney injury (18.6% vs. 13.9%, p = 0.048). The pooled 1‐year death rate revealed 41 deaths in 165 patients in the CTO group and 396 deaths in 1663 patients with no CTO ((24.8%) vs. (23.8%)). The meta‐analysis of death with CTO versus no CTO showed a nonsignificant trend toward increased mortality with CTOs (risk ratio 1.11 95% CI 0.90–1.40, I2 = 0%). Our analysis suggests that concomitant CTO lesions in patients undergoing TAVR are common, and its presence was associated with increased in‐hospital complications. However, CTO presence by itself was not associated with increased long‐term mortality, only a nonsignificant trend toward an increased risk of death in patients with CTO was found. Further studies are warranted to assess the prognostic relevance of CTO lesion in TAVR patients.
Distal versus conventional radial artery access for coronary catheterization: A systematic review and meta‐analysis
Authors: Feghaly Julien , Chen Kai , Blanco Anamarys , Pineda Andres M.
Published: February 2023

Background

The distal radial artery (DRA) access is an alternative to the conventional radial artery (CRA) access for coronary angiography and interventions and appears to be associated with reduced incidence of certain outcomes.

Methods

A systematic review was performed to evaluate differences between DRA versus CRA access for coronary angiography and/or interventions. Following preferred reporting items for systematic review and meta‐analysis‐protocols guidelines, two reviewers independently selected studies published in the electronic databases (MEDLINE, EMBASE, SCOPUS, CENTRAL) from inception to October 10, 2022, followed by data extraction, meta‐analysis, and quality assessment.

Results

The final review included 28 studies with (total: 9151 patients [DRA: 4474; CRA: 4677]). Compared with CRA, DRA access was found to be associated with a shorter time to achieve hemostasis (mean difference, MD: −32.49 [95% confidence interval, CI: −65.53, −2.46], p < 0.00001), and reduced incidence of radial artery occlusion (RAO) (risk ratio, RR: 0.38 [95% CI: 0.25, 0.57], p < 0.00001), any bleeding (RR: 0.44 [95% CI: 0.22, 0.86], p = 0.02), and pseudoaneurysm (RR: 0.41 [95% CI: 0.18, 0.99], p = 0.05). However, DRA access has increased access time (MD: 0.31 [95% CI: −0.09, 0.71], p < 0.00001) and crossover rates (RR: 2.75 [95% CI: 1.70, 4.44], p < 0.00001). There were no statistically significant differences in other technical aspects and complications.

Conclusion

DRA access is a safe and feasible approach for coronary angiography and interventions. Compared to CRA, DRA provides a shorter hemostasis time, lower incidence of RAO, any bleeding, and pseudoaneurysm, and is associated with increased access time and crossover rates.