bluuebunny/crossref_metadata_2025 huggingface dataset:
X‐ray imaging technique for in vitro tissue composition measurements using saline/iodine displacement: Technique optimization
Authors: Moreau M. , Holdsworth D. W. , Fenster A.
Published: July 2002

An in vitro radiographic technique which uses saline/iodine displacement has been developed to study the thickness of bone‐equivalent and soft‐tissue‐equivalent materials within atherosclerotic plaques in arterial specimens which have been cut open longitudinally and laid flat. Results concerning the optimization of the imaging parameters are presented and discussed. The technique consists of imaging arterial specimens under two different conditions: (1) when it is immersed in an isotonic saline solution, to estimate the calcium content, and (2) when it is immersed in a concentrated iodine solution, to estimate the total thickness of the specimen. Calibration step wedges made out of bone‐mimicking and soft‐tissue‐mimicking materials are imaged simultaneously to generate calibration curves which are used to convert the radiographs into bone‐equivalent and soft‐tissue‐equivalent thickness images. The optimal spectral parameters were determined to be 45 and 100 kVP for the saline and the iodine images, respectively, with a significant amount of added filtration for both images. Inherent systematic inaccuracies due to (1) the nonidealities due to linear attenuation coefficient mismatch between tissue and calibration materials and (2) beam hardening due to heel effect are determined theoretically, and can be used to correct a set of bone‐equivalent and the soft‐tissue‐equivalent images to within ±6 μm with an ideal, noise‐free imaging system.
Investigation of the line‐pair pattern method for evaluating mammographic focal spot performance
Authors: Goodsitt Mitchell M. , Chan Heang‐Ping , Liu Bob
Published: July 2002

The latest American College of Radiology (ACR) Mammography Quality Control Manual contains a new method for evaluating focal spot performance, which this paper refers to as the “line‐pair pattern test.” The ACR describes a variety of methods for performing this test, and does not advocate one method over another. The authors of this paper conducted an investigation to compare the optional ways for performing the test. Resolution measurements were obtained using a prototype line‐pair resolution phantom imaged with a GE DMR mammography unit. Measurements were made with the line‐pair pattern 4.5 cm above the breast support platforms in both conventional (contact) and magnification geometries. Both 4.5 cm of air and Lucite were tested as attenuators between the line‐pair pattern and the breast support platform. Image receptors that were employed included film alone, screen‐film, and screen‐film that was not allowed to wait the recommended 15 min before exposure. kVp was varied as was the orientation of the line‐pair pattern relative to the chest wall. For the air attenuator case, the screen degraded the measured resolution by 1–3 lp/mm when compared to the direct film. The Lucite attenuator reduced the resolution by an additional 1 lp/mm. Increasing kVp improved the resolution slightly for the conventional mode, but decreased it slightly for the magnification mode. Based upon the results of this study, recommendations are made for improving the test protocol. For a test of focal spot performance, one should use the no‐attenuation with direct film detector setup. For a measure of the resolution of the entire imaging chain, one should use the Lucite attenuator with screen‐film detector setup.
Electron arc dose distributions as a function of beam energy
Authors: Olivares‐Pla Marina , Podgorsak Ervin B. , Pla Conrado
Published: July 2002

The characteristic angle‐β concept provides a simple semiempirical method for determination of dose distributions in electron arc therapy. Initially, the method required a set of measured radial depth dose distributions for each electron beam energy used for arc therapy. In this paper, we report an extension of the angle‐β concept that enables the determination of arc therapy depth doses for an arbitrary electron energy from the known set of depth dose data at a reference energy. Depth dose distributions of stationary and arc electron beams have been studied in the energy range from 9 to 18 MeV. The stationary electron beams used for electron arc therapy were collimated by photon collimators only, no secondary collimation was used in our experiments. For stationary electron beams and for arc electron beams with a given characteristic angle β, the depths of dose maximum as well as the depths of a given percentage depth dose beyond the depth of dose maximum are linearly proportional to the mean incident electron energy. This simple geometrical and dosimetric relationship increases the potential usefulness of the angle‐β concept in clinical electron arc therapy.
Range spectra in electron penetration problems
Authors: Perry D. , Wollin M. , Olch A. , Buffa A.
Published: July 2002

The theory of electron penetration as predicted by the Fokker–Planck equation is first reviewed within a restricted context that considers the multiple scattering and transport of charged particles. We then broaden the context and show that range straggling effects also fit successfully into this framework, which completes an electron model initiated by Yang. We introduce those effects with a superposition of Fokker–Planck solutions, i.e., by using an incident beam that contains a spectrum of initial energies, or equivalently, a set of csda ranges. Straggling effects appear to be a beam property in this approach but are returned to the material when we use it. All the information needed to construct the spectrum is obtained from a measurement of the electron rest charge distribution in polystyrene. To illustrate the correctness of this procedure, we consider the case of a 20 MeV electron beam incident on water. We predict the absorbed dose distribution as a function of depth and also measure it with an ionization chamber in a water tank. We find nearly perfect agreement between calculation and experiment in this case where all the results derive and apply to a clinically operational machine.
Effects of lossy compression on lesion detection: Predictions of the nonprewhitening matched filter
Authors: Zhao Binsheng , Schwarz Lawrence H. , Kijewski Peter K.
Published: July 2002

The nonprewhitening matched filter (NPWMF) was used to study the effect of wavelet‐based lossy image compression on lesion detectability. Two classes of images, representing lesion‐present and lesion‐absent cases, were generated by simulation techniques. The performance index, of the NPWMF was calculated from the reconstructed images of the two classes and was used as an objective measure for quantifying signal detectability. The effect of compression on detectability was analyzed by defining signal amplitude, signal size, and noise amplitude at a constant Since human observer studies directly correlate with the performance index the effect of signal parameters on compression ratios could be evaluated. For example, a signal with 7 pixels in diameter and an amplitude of 10 that was compressed at a ratio of 4.6:1, and a signal of the same size with an amplitude of 15 but compressed at a ratio of 24.3:1, both had a of 4.1, implying identical detectability. Similar results for other combinations of signal and noise parameters, but at constant can be used to analyze the effect of compression on detectability without requiring human observer studies.
Better narrow beam profiles by exposing a stack of radiochromic films and averaging the readings
Authors: Duggan D. M. , Coffey C. W.
Published: July 2002

Radiochromic film, with its high spatial resolution and tissue‐equivalence would be excellent for obtaining crossbeam profiles of narrow radiosurgery beams, if it were not for its nonuniformity. We show that this can be largely overcome by exposing a stack of three films to a beam, reading each film separately, registering the films, and averaging the readings from all three films at each point. In this way, two‐dimensional dose distributions for a 10 mm diameter (full width at half‐maximum at isocenter) beam as well as the central square centimeter of a large (10 cm×10 cm beam were obtained. The effects of averaging three films in a stack are also compared to the results of averaging three readings of the same film. For the films uniformly irradiated in the center of the large field, the average, standard deviation, minimum, and maximum values of the dose were obtained. These statistics show that the dose distribution obtained by averaging three scans of the same film is better than the distribution from one scan, and the distribution from averaging three films in a stack is even better. A distribution was judged to be better if the average dose was closer to the actual dose, the standard deviation was smaller, and the minimum and maximum were closer together.
Direct measurement and analytical modeling of scatter in portal imaging
Authors: Spies L. , Evans P. M. , Partridge M. , Hansen V. N. , Bortfeld T.
Published: July 2002

In this study a direct measurement of scatter in portal imaging for various air gaps and scatterer thicknesses at a beam energy of 6 MV is presented. The experimental data are compared with results from a Monte Carlo (MC) scatter model. In the regime where the air gap is larger than 9.3 cm the MC and the experiment agree. Based on this MC model an analytical model is developed, which takes all important interaction processes into account. It comprises a rigorous treatment of first order scattering and an estimation of photons scattered more than once within the phantom. This estimation is based on the assumption that higher order scattering can be considered as isotropically distributed around a certain scatter origin located in the midplane of the phantom. It is found that relative deviations between the MC model and the analytical model are of 2% to 3% in regions where scattering is very large.
Localization of cochlear implant electrodes in radiographs
Authors: Yang Siying , Wang Ge , Skinner Margaret W. , Rubinstein Jay T. , Vannier Michael W.
Published: July 2002

Multielectrode cochlear implantation is the most effective treatment for profound sensorineural hearing loss. In vivo three‐dimensional 3‐D localization of cochlear implant electrodes is important for modeling of the electrical field in the cochlea, design of electrode arrays, and may improve speech processor programming for better speech recognition. The prerequisite for 3‐D localization of the electrodes is their 2‐D localization in x‐ray radiographs. In this paper, we develop a practical method to localize the electrodes with high efficiency, accuracy, and reproducibility. In this method, a priori knowledge of the electrodes and their approximate positions are utilized, an intelligent thresholding and segmentation mechanism is embedded, and the electrode center is computed as the weighted geometric center of segmented electrode pixels. Experiments with physical phantoms and human data demonstrate the feasibility and utility of this method. The PC‐based program developed for this project is disseminated on the Web.
A localization algorithm and error analysis for stereo x‐ray image guidance
Authors: Jiang Hangyi , Liu Hong , Wang Ge , Chen Wei , Fajardo Laurie L.
Published: July 2002

Stereo x‐ray radiography attracts increasing attention in major clinical applications. The purpose of this paper is to analyze the 3D localization error for breast biopsy procedures and provide guidelines for improving its accuracy. Our prototype is a CCD based digital stereo x‐ray imaging system. The mathematical model consists of two x‐ray sources and one stationary detector plane. A closed form least‐squares solution is derived for 3D localization of feature points, particularly a biopsy needle tip, from a pair of 2D digital radiographs. Based on the least‐squares formula and its first order approximation, the 3D localization error is analyzed in terms of object location, measurement error, separation between the two x‐ray sources, and distance from the source to the detector. The stereo imaging and error estimation formulas are numerically simulated and experimentally validated. The data are in agreement with theoretical prediction. These results can be used for the purpose of system design and protocol optimization.
Photon quantum mechanics and beam splitters
Authors: Holbrow C. H. , Galvez E. , Parks M. E.
Published: July 2002

We are developing materials for classroom teaching about the quantum behavior of photons in beam splitters as part of a project to create five experiments that use correlated photons to exhibit nonclassical quantum effects vividly and directly. Pedagogical support of student understanding of these experiments requires modification of the usual quantum mechanics course in ways that are illustrated by the treatment of the beam splitter presented here.
Tunnel splittings for one-dimensional potential wells revisited
Authors: Garg Anupam
Published: July 2002

The Wentzel–Kramers–Brillouin and instanton answers for the tunnel splitting of the ground state in a symmetric double-well potential are both reduced to an expression involving only functionals of the potential, without the need for solving any auxilliary problems. This formula is applied to simple model problems. The prefactor for the splitting in the textbook by Landau and Lifshitz is amended so as to apply to the ground and low lying excited states.
Interaction between adenosine triphosphate and mechanically induced modulation of electrically evoked otoacoustic emissions
Authors: Kirk Desmond L.
Published: July 2002

It was shown previously that electrically evoked otoacoustic emissions (EEOAEs) can be amplitude modulated by low-frequency bias tones and enhanced by application of adenosine triphosphate (ATP) to scala media. These effects were attributed, respectively, to the mechano-electrical transduction (MET) channels and ATP-gated ion channels on outer hair cell (OHC) stereocilia, two conductance pathways that appear to be functionally independent and additive in their effects on ionic current through the OHC. In the experiments described here, the separate influences of ATP and MET channel bias on EEOAEs did not combine linearly. Modulated EEOAEs increased in amplitude, but lost modulation at the phase and frequency of the bias tone (except at very high sound levels) after application of ATP to scala media, even though spectral components at the modulation sideband frequencies were still present. Some sidebands underwent phase shifts after ATP. In EEOAEs modulated by tones at lower sound levels, substitution of the original phase values restored modulation to the waveform, which then resembled a linear summation of the separate effects of ATP and low-frequency bias. While the physiological meaning of this procedure is not clear, the result raises the possibility that a secondary effect of ATP on one or more nonlinear stages in the transduction process, which may have caused the phase shifts, obscured linear summation at lower sound levels. In addition, “acoustic enhancement” of the EEOAE may have introduced nonlinear interaction at higher levels of the bias tones.
Single half-wavelength ultrasonic particle filter: Predictions of the transfer matrix multilayer resonator model and experimental filtration results
Authors: Hawkes Jeremy J. , Coakley W. Terence , Gröschl Martin , Benes Ewald , Armstrong Sian , Tasker Paul J. , Nowotny Helmut
Published: July 2002

The quantitative performance of a “single half-wavelength” acoustic resonator operated at frequencies around 3 MHz as a continuous flow microparticle filter has been investigated. Standing wave acoustic radiation pressure on suspended particles (5-μm latex) drives them towards the center of the half-wavelength separation channel. Clarified suspending phase from the region closest to the filter wall is drawn away through a downstream outlet. The filtration efficiency of the device was established from continuous turbidity measurements at the filter outlet. The frequency dependence of the acoustic energy density in the aqueous particle suspension layer of the filter system was obtained by application of the transfer matrix model [H. Nowotny and E. Benes, J. Acoust. Soc. Am. 82, 513–521 (1987)]. Both the measured clearances and the calculated energy density distributions showed a maximum at the fundamental of the piezoceramic transducer and a second, significantly larger, maximum at another system’s resonance not coinciding with any of the transducer or empty chamber resonances. The calculated frequency of this principal energy density maximum was in excellent agreement with the optimal clearance frequency for the four tested channel widths. The high-resolution measurements of filter performance provide, for the first time, direct verification of the matrix model predictions of the frequency dependence of acoustic energy density in the water layer.
Spectral Green’s function for wave excitation and propagation in a piezoelectric, continuously twisted, structurally chiral medium
Authors: Lakhtakia Akhlesh , Robbie Kevin , Brett Michael J.
Published: July 2002

A continuously twisted, structurally chiral medium (CTSCM) is a reciprocal medium whose constitutive properties vary helicoidally along its axis of spirality (say, the z axis), and the corresponding piezoelectric medium is abbreviatedly called the PCTSCM. Very recent progress in thin-film research is presented here to show that technologically significant CTSCM’s and PCTSCM’s are waiting in the wings and calling for theoretical advances in the understanding of wave excitation and propagation in these novel materials. A spectral Green’s function is obtained as a bilinear composition of two matrices, after implementing a spatial Fourier transform in the xy plane as well as the Oseen transformation. As a result, multilayered media problems as well as grating problems utilizing CTSCM’s and PCTSCM’s become accessible to theoretical exploration leading to novel transducers, sensors, and other devices.
Placing constrained layer damping patches using reactive shearing structural intensity measurements
Authors: Kruger Daniel H. , Adin Mann J. , Wiegandt Ted
Published: July 2002

The use of reactive shearing structural intensity to place small patches of constrained layer damping material in order to achieve the largest reduction in the radiated sound power of a cubic structure is described. The normal surface velocity of a square plate was measured using a laser vibrometer. The plate was measured with no damping and with various damping configurations. Reactive structural intensity was calculated for the undamped plate for velocity distributions at resonance frequencies of the first and third modes of the plate. A cube was simulated by placing various measured plate velocity distributions at these same two frequencies on one side of the cube while leaving the remaining five sides rigid. The sound power radiated by the cubic structure as a function of normal surface velocity was written using the boundary element method. Experimental results indicated that patches of constrained layer damping material placed over areas of high reactive structural intensity reduced the radiated sound power significantly more than patches of the same area placed over areas of low reactive structural intensity. Reductions as high as 10.25 dB were achieved for patches comprising only 6.4% of the area of one side of the cube by varying the number, size, shape, and placement of constrained layer damping patches to correspond to areas where the reactive shearing structural intensity magnitude was high.
Stochastic ray theory for long-range sound propagation in deep ocean environments
Authors: Brown Michael G. , Viechnicki John
Published: July 2002

The motion of sound ray trajectories in deep ocean environments, including internal wave induced scattering, is considered. Using the empirical Garrett–Munk internal wave spectrum and results from the study of stochastic differential equations, a framework for studying and modeling stochastic ray motion is developed. It is argued that terms in the ray equations involving internal wave induced sound speed perturbations δc can be neglected, but those involving ∂δc/∂z cannot. It is then shown in that the (Markov) approximation that spatial variations of ∂δc/∂z are delta correlated is remarkably good. These results lead naturally to an extremely simple system of coupled stochastic ray equations (in ray depth z, ray slowness p and travel time T) in which stochasticity enters the system only through the equation for p. Solutions to the stochastic ray equations—or the corresponding Fokker–Planck equation—describe approximately the density of acoustic energy in range, depth, angle and time. Two dimensionless parameters are introduced: (1) an acoustic Péclet number which is a measure of the ratio of the strength of deterministic ray refraction to that of stochastic scattering induced ray diffusion; and (2) a measure of the ratio of the strength of scattering induced ray diffusion to that of wave diffraction. Numerical solutions to the stochastic ray equations are compared to full wave simulations. These results show that, even in the weak scattering regime (large acoustic Péclet number), the inclusion of internal wave induced scattering may lead to important qualitative corrections to predictions of distributions of acoustic energy.
A new theoretical approach to photoacoustic signal generation
Authors: Hoelen C. G. A. , de Mul F. F. M.
Published: July 2002

From the various mechanisms of photoacoustic (PA) signal generation, the one due to local thermal expansion in aqueous media is treated here in detail. This mechanism is also referred to as thermoelastic PA signal generation. A new physical explanation of the spherical PA profile is presented, from which the signals generated by other source geometries and temporal profiles can be deduced. The characteristic PA signal profiles are discussed for some fundamental and practical source geometries. Also the PA signal attenuation and deformation due to viscous and thermoelastic losses is discussed. The analytic result for the transient generated by a spherical Gaussian spatiotemporal PA source is presented. Experimental PA signals are shown for several geometries and source diameters.
Comments on “Mode coupling by internal waves for multimegameter acoustic propagation in the ocean” [J. Acoust. Soc. Am. 100, 3607–3620 (1996)]
Authors: Virovlyansky Anatoly L.
Published: July 2002

The results of numerical simulation presented in the subject paper shows that sound pulses carried by individual high modes in an underwater acoustic waveguide at ranges of a few thousand km are severely distorted due to inhomogeneities induced by random internal waves. At the same time, the total wave field reveals a rather coherent pattern, where raylike wavefronts are evident. Here, comment is made on this interesting result from the viewpoint of ray-mode relations in a waveguide with large-scale refractive index inhomogeneities. It is shown that when very distorted mode arrival patterns are synthesized together, the result is a much less distorted ray-arrival pattern.
Target strength of an oily deep-water fish, orange roughy (Hoplostethus atlanticus) II. Modeling
Authors: McClatchie Sam , Ye Zhen
Published: July 2002

Orange roughy consist of ∼18% lipids by weight, mostly as wax esters, and the lipids must be taken into account when modeling target strength. A deformed cylinder model incorporating the effect of temperature and pressure on sound speed through wax ester was used to scale experimental measurements of target strength to the temperatures and pressures where orange roughy live (∼6 °C, depths ∼800–1300 m). The effect of decreasing temperature and increasing pressure is to increase the sound speed in orange roughy lipids. Modeling shows that the net effect of this is to reduce tilt-averaged target strength, 〈TS〉, by ∼2 dB. Adjusting experimental results to compensate for temperature and pressure effects gives a predicted 〈TS〉 for a 35-cm orange roughy of −48.3 dB. Adjusting in situ estimates of orange roughy 〈TS〉 for avoidance behavior [McClatchie et al., J. Acoust. Soc. Am. 106, 131–142 (1999)] suggests the correct 〈TS〉 is ∼−47.5 dB, rather than −50 dB as previously reported [Kloser et al., ICES J. Mar. Sci. 54, 60–71 (1997)]. We conclude that experimental and in situ estimates now converge at a 〈TS〉 of ∼−48 dB for a 35-cm fish.
Determining impact source location in structural networks
Authors: Dickey Joseph , Maidanik Gideon
Published: July 2002

An impact, or similar event, generates a transient in a structural network consisting of connected one-dimensional systems. A sensor, attached at an arbitrary point in the network, will ‘‘hear’’ a complicated time series of pulses. A few of these pulses are recorded and used to generate a time-reversed series which is injected at the sensor location. If the network is stationary in time, the impulse response function (IRF) can be used to show that the introduced series will constructively interfere at the original impact point and this location can thereby be determined. The procedure is demonstrated computationally using a time-domain IRF. The relationship between the above and ‘‘reciprocity’’ and ‘‘inverse filtering’’ will be discussed.
Modulation detection interference with narrow-band noise interferers
Authors: Verhey Jesko , Dau Torsten
Published: July 2002

The detection of amplitude modulation of a sinusoidal (target) carrier can be impaired by the presence of a modulated sound (interferer) with a different carrier frequency, referred to as modulation detection interference (MDI). Typically, sinusoidally amplitude-modulated tones remote in frequency are used as the interferer, and the target modulation threshold is increased if the interferer- and target-modulation rates are similar. In the present study, narrow-band noise was used as the interferer. Detection thresholds for modulations of 5, 10, and 50 Hz imposed on tone carriers were measured as a function of noise bandwidth (0–200 Hz), the spectral distance between the carrier and interferer (0.5–4 octaves), the carrier level (40–80 dB SPL), and the carrier-interferer level difference (0–30 dB). In all conditions, the intrinsic fluctuations of the noise interfered with modulation detection, with maximum interference at noise bandwidths about twice the modulation frequency. This bandwidth dependence corresponds directly to that found in ‘‘on-frequency’’ conditions with narrow-band noise carriers; however, the interference is much smaller. An across-channel modulation-filterbank model is used to describe the similar bandwidth dependence and the different overall effectiveness of the on- and off-frequency interferer. [Work supported by the Deutsche Forschungsgemeinschaft.]
Time reversal and the inverse filter
Authors: Tanter Mickaël , Thomas Jean-Louis , Fink Mathias
Published: July 2002

To focus ultrasonic waves in an unknown inhomogeneous medium using a phased array, one has to calculate the optimal set of signals to be applied on the transducers of the array. In the case of time-reversal mirrors, one assumes that a source is available at the focus, providing the Green’s function of this point. In this paper, the robustness of this time-reversal method is investigated when loss of information breaks the time-reversal invariance. It arises in dissipative media or when the field radiated by the source is not entirely measured by the limited aperture of a time-reversal mirror. However, in both cases, linearity and reciprocity relations ensure time reversal to achieve a spatiotemporal matched filtering. Nevertheless, though it provides robustness to this method, no constraints are imposed on the field out of the focus and sidelobes may appear. Another approach consists of measuring the Green’s functions associated to the focus but also to neighboring points. Thus, the whole information characterizing the medium is known and the inverse source problem can be solved. A matrix formalism of the propagation operator is introduced to compare the time-reversal and inverse filter techniques. Moreover, experiments investigated in various media are presented to illustrate this comparison.
Conservation translocations from the ‘Global Reintroduction Perspectives’ series: Disease and other biological problems
Authors: Beckmann Katie M. , Soorae Pritpal S.
Published: August 2022

Conservation translocations, defined as population reinforcement, reintroduction, assisted colonization or ecological replacement, have become a popular tool in efforts to restore wildlife populations and their wider ecosystems. Given that conservation translocations remain challenging to undertake, and positive outcomes are not guaranteed, we should maximize opportunities to learn from the outcomes of previous projects.

Case studies of animal and plant conservation translocation published in the first six volumes (2008–2018) of the IUCN/SSC's ‘Global Reintroduction Perspectives’ series were reviewed. Alongside project metadata, the following self‐reported information was extracted from the case studies: select project strategies and methods; information relating to any mortality, ill‐health or poor fecundity; and health management practices.

Two hundred and ninety‐five of the 351 case studies clearly described a discrete conservation translocation initiative for which releases were underway or complete at their time of publication. Sixty per cent of these 295 case studies were reintroductions. Mammals were the most commonly translocated taxon (29% of case studies), and projects were most often conducted in Oceania, Western Europe or North America or the Caribbean.

The data set presents information on disease and other biological problems self‐reported in these conservation translocation case studies. It can inform health and wider management planning for future conservation translocation projects.
Lack of national strategy leaves uneven availability of gambling services
Authors: Enos Gary
Published: August 2022

As technology continues to make gambling more accessible, thereby creating more potential risk of addiction for some, those who do develop problems are still relying on a patchwork system that makes their luck in finding treatment largely dependent on geography.
MTF: Cannabis use with vaping goes up, use without vaping down
Authors: Knopf Alison
Published: August 2022

More and more high schoolers are using marijuana by vaping, and fewer are using it by smoking, according to a recent study of the Monitoring the Future (MTF) survey conducted by the National Institute on Drug Abuse (NIDA). So the next time you hear someone say that marijuana use in teens is going down, ask them about the route of administration.
Study: People leaving jail should get take‐homes
Authors: Knopf Alison
Published: August 2022

Providing methadone, buprenorphine, or naltrexone to inmates to treat their opioid use disorder (OUD) shows great promise in reducing the risk of overdose when they are released from jail. That release period, the period of reentry, is the most dangerous for these drug users. But more than that is needed—they need to leave prison or jail with the medication, a study has found.
Manipulating and Optimizing the Hierarchically Porous Electrode Structures for Rapid Mass Transport in Solid Oxide Cells
Authors: Hou Mingyang , Pan Yuxin , He Fan , Xu Kang , Zhang Hua , Zhou Yucun , Zhao Bote , Chen Yu , Liu Meilin
Published: August 2022

Over the past decades, considerable efforts have been made to develop hierarchically porous electrodes for the high surface area, the fast velocity of fuels/products to/away from the reaction site, and the high loading of thermal‐ and/or electrochemical‐ catalysts. Manipulation of the hierarchical structure is one of the key steps for high performance in applications of efficient energy storage and conversion such as solid oxide cells. This review starts with a brief introduction to the basic concept of mass transport and how mass transport may affect performance. Then, the latest developments in enhancing the performance of cells through modification or optimization of the hierarchically porous electrode structures, including altering the geometry or morphology and increasing the triple‐phase boundaries length of electrodes are summarized. Subsequently, the unique characteristics of microstructures that are critical to enhancing electrode performance and provide important insights into the mechanisms of performance (activity and durability) enhancement, aiming at achieving the rational design of better electrode architecture are highlighted. Finally, the remaining challenges for the knowledge‐based design of highly efficient electrodes for electrochemical devices, together with possible directions and future perspectives for the development of highly efficient electrodes through optimization of microstructure are discussed.
Nanopatterning on Mixed Halide Perovskites for Promoting Photocurrent Generation of Flexible Photodetector
Authors: Chun Do Hyung , Kim Seongchan , Park Jumi , Lee SunJe , Kim Wook , Lee Jung Hwan , Rhee Ryan , Kim Tae Gyun , Choi Dae Geun , Choi Dukhyun , Kim Dongho , Cho Jeong Ho , Park Jong Hyeok
Published: August 2022

Nanoimprinting lithography (NIL) technique is widely utilized for nanostructure engineering of soft materials. Owing to the soft organic/inorganic hybrid nature, the optical and crystallographic properties of halide perovskites (HPs) are improved by the NIL process. However, the wide application of NIL into various HPs has lagged. Herein, a defect‐free nanopatterned‐(FAPbI3)0.85(MAPbBr3)0.15 (NP‐FAMA) film is successfully developed via optimized NIL. As surface energy is a key parameter to be controlled for accomplishing NIL process, trichloro(1H,1H,2H,2H‐perfluorooctyl)silane (CF3(CF2)5CH2CH2SiCl3) treatment on polymeric mold, which prevents the peeling‐off problem. Along with surface morphology modification, NP‐FAMA exhibits enhanced crystallographic and photophysical properties. The photoresponsivity of NP‐FAMA‐based photodetectors outperforms bare (b‐) FAMA‐based devices. Surprisingly, the external quantum efficiency (EQE) of the NP‐FAMA‐based devices dramatically increases to 225%, photomultiplication (PM), under 1 nW illumination without any charge‐injecting materials. To clarify these PM phenomena, the trap‐assisted PM mechanism is suggested as a model system for promoting photocurrent generation of HPs that is supported by PL analysis.
An Aqueous Analog MAC Machine
Authors: Jung Woo‐Bin , Jung Han Sae , Wang Jun , Hinton Henry , Fournier Maxime , Horgan Adrian , Godron Xavier , Nicol Robert , Ham Donhee
Published: August 2022

Using ions in aqueous milieu for signal processing, like in biological circuits, may potentially lead to a bioinspired information processing platform. Studies, however, have focused on individual ionic diodes and transistors rather than circuits comprising many such devices. Here a 16 × 16 array of new ionic transistors is developed in an aqueous quinone solution. Each transistor features a concentric ring electrode pair with a disk electrode at the center. The electrochemistry of these electrodes in the solution provides the basis for the transistor operation. The ring pair electrochemically tunes the local electrolytic concentration to modulate the disk's Faradaic reaction rate. Thus, the disk current as a Faradaic reaction to the disk voltage is gated by the ring pair. The 16 × 16 array of these transistors performs analog multiply–accumulate (MAC) operations, a computing modality hotly pursued for low‐power artificial neural networks. This exploits the transistor's operating regime where the disk current is a multiplication of the disk voltage and a weight parameter tuned by the ring pair gating. Such disk currents from multiple transistors are summated in a global reference electrode to complete a MAC task. This ionic circuit demonstrating analog computing is a step toward sophisticated aqueous ionics.
Construction of Ultrathin S‐Scheme Heterojunctions of Single Ni Atom Immobilized Ti‐MOF and BiVO4 for CO2 Photoconversion of nearly 100% to CO by Pure Water
Authors: Zhao Lina , Bian Ji , Zhang Xianfa , Bai Linlu , Xu Linyao , Qu Yang , Li Zhijun , Li Yuxin , Jing Liqiang
Published: August 2022

To rationally design single‐atom metal–organic framework (MOF)‐involving photocatalysts remains an ongoing challenge for efficient CO2 conversion. Here, cuppy microstructures, consisting of a Ti(IV)‐oxo node and three linked carboxylic moieties, in the single‐coordination‐layer Ti2(H2dobdc)3 MOF (NTU‐9) are exploited to immobilize abundant single Ni(II) sites (Ni@MOF). The coupling of Ni@MOF with BiVO4 (BVO) nanosheets by H‐bonding‐induced assembly process obtains wide‐spectrum 2D heterojunctions. The optimal heterojunction exhibits competitive performance and enables around 66‐fold CO2 conversion of that for BVO nanoparticles by pure water, with nearly 100% CO selectivity. The exceptional photoactivity is attributed to favorable S‐scheme charge transfer from BVO to MOF then to single Ni(II) sites. Noteworthily, single Ni(II) sites anchored by the Ti(IV)‐oxo node and vicinal carboxylic moieties serving as a unique local microenvironment (LME) are found to synergistically catalyze CO2 conversion. Specifically, the hydroxyl groups of carboxylic moieties can form H‐bonds with CO2 to promote its adsorption on single Ni(II) sites, and also can provide accessible protons to facilitate H‐assisted CO2 reduction. Moreover, the CO desorption and subsequent CO2 adsorption on single Ni(II) sites with LME is proved to be thermodynamically favored, and hence dominates the high CO selectivity. This work highlights the significance of modulating the LME of single atoms to rationally design photocatalysts for realizing carbon neutralization.
A Zinc‐Ion Battery‐Type Self‐Powered Pressure Sensor with Long Service Life
Authors: Zhang Qixiang , Lei Dandan , Liu Nishuang , Liu Zunyu , Ren Ziqi , Yin Jianyu , Jia Peixue , Lu Wenzhong , Gao Yihua
Published: August 2022

Accurate and continuous pressure signal detection without external power supply is a key technology to realize the miniaturization of wearable electronic equipment, the internet of things, and artificial intelligence. However, it is difficult to be achieved by using current sensor technologies. Here, a new one‐body strategy, i.e., zinc‐ion battery pressure (ZIB‐P) sensor technology, which designs the rechargeable solid‐state ZIB itself as a flexible pressure sensor is reported. In the device, an isolation layer is introduced into the sandwich configuration solid‐state battery to realize the change of device internal resistance by pressure during the transformation of the mechanical signal to the electrical signal. This battery pressure sensor possesses good flexibility, fast response/recovery time (76.0/88.0 ms), stable long‐term response, excellent cycle stability (100 000 times), and wide pressure detection range (2.0 to 3.68 × 105 Pa). Especially, the excellent charge–discharge performance in the ZIB‐P sensor endows it with the real‐time detection ability of human vital signs (pulse, limb movement, etc.) and ultrahigh stability without degradation even under 100 000 times pressure stimulation. The ZIB‐P sensor strategy provides a new solution for the future development of miniaturized wearable electronic devices.
MoSe2–VSe2–NbSe2 Ternary Alloy Nanosheets to Boost Electrocatalytic Hydrogen Evolution Reaction
Authors: Kwon Ik Seon , Kwak In Hye , Zewdie Getasew Mulualem , Lee Seung Jae , Kim Ju Yeon , Yoo Seung Jo , Kim Jin‐Gyu , Park Jeunghee , Kang Hong Seok
Published: August 2022

Alloying of transition metal dichalcogenides (TMDs) is a pioneering method for engineering electronic structures with expanded applications. In this study, MoSe2–VSe2–NbSe2 ternary alloy nanosheets are synthesized via a colloidal reaction. The composition is successfully tuned over a wide range to adjust the 2H–1T phase transition. The alloy nanosheets consist of miscible atomic structures at all compositions, which is distinct from immiscible binary alloys. Compared to each binary alloy, the ternary alloys display higher electrocatalytic activity toward the hydrogen evolution reaction (HER) in an acidic electrolyte. The HER performance exhibits a volcano‐type composition dependence, which is correlated with the experimental d‐band center (εd). Spin‐polarized density functional theory (DFT) calculations consistently predict the homogenous atomic distributions. The Gibbs free energy of H adsorption (ΔGH*) and the activation barrier (Ea) support that miscible ternary alloying greatly enhances the HER performance.
A Peritumorally Injected Immunomodulating Adjuvant Elicits Robust and Safe Metalloimmunotherapy against Solid Tumors
Authors: Zhang Lingxiao , Zhao Jing , Hu Xi , Wang Chenhan , Jia Yingbo , Zhu Chaojie , Xie Shangzhi , Lee Jiyoung , Li Fangyuan , Ling Daishun
Published: August 2022

Clinical immunotherapy of solid tumors elicits durable responses only in a minority of patients, largely due to the highly immunosuppressive tumor microenvironment (TME). Although rational combinations of vaccine adjuvants with inflammatory cytokines or immune agonists that relieve immunosuppression represent an appealing therapeutic strategy against solid tumors, there are unavoidable nonspecific toxicities due to the pleiotropy of cytokines and undesired activation of off‐target cells. Herein, a Zn2+ doped layered double hydroxide (Zn‐LDH) based immunomodulating adjuvant, which not only relieves immunosuppression but also elicits robust antitumor immunity, is reported. Peritumorally injected Zn‐LDH sustainably neutralizes acidic TME and releases abundant Zn2+, promoting a pro‐inflammatory network composed of M1‐tumor‐associated macrophages, cytotoxic T cells, and natural‐killer cells. Moreover, the Zn‐LDH internalized by tumor cells effectively disrupts endo‐/lysosomes to block autophagy and induces mitochondrial damage, and the released Zn2+ activates the cGas‐STING signaling pathway to induce immunogenic cell death, which further promotes the release of tumor‐associated antigens to induce antigen‐specific cytotoxic T lymphocytes. Unprecedentedly, merely injection of Zn‐LDH adjuvant, without using any cytotoxic inflammatory cytokines or immune agonists, significantly inhibits the growth, recurrence, and metastasis of solid tumors in mice. This study provides a rational bottom‐up design of potent adjuvant for cancer metalloimmunotherapy against solid tumors.
MAB‐Phases and Beyond—A Tribological Success Story?
Authors: Rosenkranz Andreas , Zambrano Dario , Przyborowski Alexandra , Shah Raj , Jastrzębska Agnieszka Maria
Published: August 2022

Early transition metal borides (MAB‐phases) are extensively investigated due to their excellent mechanical and tribological properties. These characteristics of ternary transition metal borides have created a promising pathway to achieve strong materials with unique properties. These layered materials combine both metallic and ceramic attributes and possess intriguing properties such as excellent mechanical, chemical, and thermal stability. Most of the MAB‐phases were discovered before the 1990s, but recent discoveries of their derivatives, such as i‐MAB phases, and MBenes, have boosted their “renaissance.” Altogether, this perspective summarizes the existing state‐of‐the‐art regarding the tribological performance of the most promising MAB‐phases and further discusses their success story in potential applications. Since the story of their derivative phases regarding mechanical/tribological applications has just begun, going beyond MAB‐phases is highly promising to explore novel high‐strength materials.
Positively Charged Poly(Piperazinamide) Nanofiltration Membranes for the Fast Removal of Metal Ions
Authors: Liu Ying , Kong Jinfeng , Bian Xiangying , Zhang Yuping , Ji Miaozhou , Peng Quan , Jin Jian , Zhu Yuzhang
Published: August 2022

Positively charged nanofiltration (NF) membranes with high perm‐selectivity are highly desired to remove divalent cations such as Ca2+ and Mg2+ ions to ensure the safety of domestic and industrial water supply. In this work, a poly(piperazinamide) NF membrane with a positively charged surface is fabricated via the surfactant‐assembly regulated interfacial polymerization (SARIP) of piperazine (PIP) and 1,3,5‐trimesoyl chloride (TMC). The surfactant assembly can accelerate PIP monomer into the hexane to react with TMC monomer, thus reducing the difference in the trans‐interface diffusion of PIP and the diffusion of TMC in hexane, forming an interfacial polymerization with a stoichiometric characteristic. By tuning the concentration ratio of PIP and TMC, a positively charged poly(piperazinamide) NF membrane will be achieved. At the same time, utilizing the superior hydrophilicity of bacterial cellulose nanofibers nanofilm, a crumpled poly(piperazinamide) active layer is successfully constructed, resulting in a permeating flux up to 22 L m−2 h−1 bar−1 and simultaneously with a MgCl2 rejection >96%. The performance of this positively charged poly(piperazinamide) NF membrane is superior to most other positive NF membranes for the removal of divalent cations so far.
Tailored ZnO Functional Nanomaterials for Solution‐Processed Quantum‐Dot Light‐Emitting Diodes
Authors: Mokarian Zanjani Saeedeh , Tintori Francesco , Sadeghi Sadra , Linkov Pavel , Dayneko Sergey , Shahalizad Afshin , Pahlevaninezhad Hamid , Pahlevani Majid
Published: August 2022

Recent improvements in efficiency and luminance of quantum‐dot light‐emitting diodes (QLEDs) promise a versatile technology for next‐generation lighting and display applications. This is accomplished due to the advances in colloidal quantum‐dot (CQD) synthetic methods together with proper engineering of the charge balance in these devices. The exciton quenching mechanisms occurring at the interface between the QD emissive layer and the zinc oxide (ZnO) electron transport layer (ETL) are one of the important parts of the charge transport path, affecting efficiency and long‐term stability. Herein, a comprehensive overview of the advances in the engineering of ZnO‐based ETLs, in terms of device efficiency and operational stability, is attempted. It is specifically highlighted that significant improvements can be achieved using various ZnO ETL defect passivation methods. This review also describes the key requirements for high‐performance QLEDs from the ETL engineering aspect and catalyzes for further interdisciplinary explorations to realize reliable devices for practical applications.
Paying Comprehensive Attention to the ESPT Mechanism and Luminescent Property of Salicylic Acid and Its Derivatives in Various Microenvironments
Authors: Shang Changjiao , Cao Yunjian , Zhang Yajie , Ma Min , Sun Chaofan
Published: August 2022

Investigating the effects of surrounding microenvironments and substituents on the excited‐state proton transfer (ESPT) mechanism have always been a great challenge, especially in protic solvents and solid state. In this work, a detailed theoretical study on ESPT processes of salicylic acid (SA) and its two derivatives (5ASA and 5NSA) in gas, cyclohexane, acetonitrile, ethanol (EtOH), and crystal phases is performed based on the density functional theory (DFT) and time‐dependent DFT as well as the combined quantum mechanics/molecular mechanics (QM/MM) methods. Intramolecular charge transfer‐induced aggregation‐caused quenching phenomenon of 5ASA is unveiled utilizing the hole–electron analysis. Independent gradient model analysis is implemented to reveal the spontaneous forward proton transfer (PT) behavior of 5ASA. Besides, potential energy surfaces are constructed to evaluate the dominant PT pathway in EtOH, and the related transition state structures are also obtained to accurately provide the intra‐ and inter‐PT energy barriers. Eventually, excited‐state ab initio molecular dynamics computation reaffirms that the intra‐PT reaction is predominant for SA. This theoretical work comprehensively explores the ESPT mechanism and luminescent properties of SA and its two derivatives, which provides a reference for developing efficient organic light‐emitting materials based on ESPT chromophores.