bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic portal imaging with an avalanche‐multiplication‐based video camera
Authors: Pang G. , Rowlands J. A.
Published: July 2002

The aim of this study is to investigate the degree to which the imaging quality of an existing (video‐based) electronic portal imaging device (EPID) system may be improved by using an avalanche‐multiplication‐based video camera (called the avalanche‐gain method). Due to avalanche multiplication in the target of the video camera tube, the new camera can be made up to several hundred times more sensitive than a camera using a conventional video (e.g., Saticon) tube. As a result, the camera noise which limits the performance of current video‐based EPIDs should be overwhelmed and made negligible. The detective quantum efficiency (DQE) of an EPID using the avalanche‐gain method has been measured with 6 MV and 18 MV beams obtained using a linear accelerator. It is shown that the camera noise is indeed much smaller than quantum noise and that the DQE of the system is significantly increased compared to conventional video‐based EPIDs. Variation of DQE of the avalanche‐gain video portal system with a change of demagnification was also investigated. It has been shown that the improvement of optical coupling has less effect in this system than that in a conventional video‐based EPID system.
In vivo biodistribution of and internal dosimetry of radioiodinated agents selective to the muscarinic acetylcholinergic receptor complex
Authors: Breeden William K. , Hamby David M. , Carey James E. , Eckerman Keith F. , McPherson Daniel W. , Knapp Furn F.
Published: July 2002

The development of new radioiodinated ligands for imaging the muscarinic acetylcholinergic complex (mAChR) using single photon emission computed tomography (SPECT) requires the evaluation of human organ doses prior to approval for human use. Animal biodistribution and excretion data were obtained and evaluated for IPIP, a new mAChR agent. Preliminary biodistribution studies were performed on four different stereoisomers of IPIP. A biokinetic model of the stereoisomer was constructed for the rat and used to estimate the internal absorbed dose in humans based on an extrapolation of the rat model. The thyroid is the critical organ for this radiopharmaceutical, with an absorbed dose estimate of 2.4 mGy/MBq for both males and females, when labeled with Even when blocked, the thyroid is still the critical organ, yet with a 90% dose reduction. The heart and brain receive the next highest doses in both males and females. Effective dose estimates for the use of pure in humans are 0.16 mSv/MBq for males and 0.14 mSv/MBq for females. The biodistribution studies of the stereoisomer showed the most promise as a successful agent for imaging muscarinic receptor sites in the heart and brain. IPIP also demonstrated potential as a therapeutic radiopharmaceutical for some colon carcinomas where muscarinic receptor sites are expressed in the tumor cells. These results provide preliminary data for use of IPIP in clinical studies on humans.
Regularization methods for delta-function potential in two-dimensional quantum mechanics
Authors: Nyeo Su-Long
Published: July 2002

The quantum mechanics of a bound particle in the delta-function potential in two dimensions is studied with a discussion of its regularization and renormalization. A simple regularization approach is considered with the introduction of several regularizing functions for defining the quantum system. More systematic regularization is introduced from the mathematical viewpoint of the theory of distributions. The renormalization scheme independence of the physical observable is demonstrated.
Matched-impulse-response processing for shallow-water localization and geoacoustic inversion
Authors: Michalopoulou Zoi-Heleni
Published: July 2002

In this paper, impulse response matching is proposed for source localization and environmental inversion. The ocean impulse response is estimated using a cross-correlation procedure applied to data from the propagation of a broadband pulse in a shallow-water environment. Source localization and geoacoustic parameter estimation are then performed through time-domain correlations between the estimated impulse responses at spatially separated phones and synthetic replica impulse responses. The method is both spatially and temporally coherent. Parameter space search uses a hierarchical scheme designed to exploit the sensitivity of the acoustic field to the unknown parameters. Tested on the SWellEX-96 and synthetic data, the proposed method is shown to be more robust than conventional (linear), incoherent, broadband matched field processing.
A concept for a research tool for experiments with cochlear implant users
Authors: Geurts Luc , Wouters Jan
Published: July 2002

APEX, an acronym for computer A¯pplication for P¯sycho-E¯lectrical eX¯periments, is a user friendly tool used to conduct psychophysical experiments and to investigate new speech coding algorithms with cochlear implant users. Most common psychophysical experiments can be easily programmed and all stimuli can be easily created without any knowledge of computer programing. The pulsatile stimuli are composed off-line using custom-made MATLAB (Registered trademark of The Mathworks, Inc., http://www.mathworks.com) functions and are stored on hard disk or CD ROM. These functions convert either a speech signal into a pulse sequence or generate any sequence of pulses based on the parameters specified by the experimenter. The APEX personal computer (PC) software reads a text file which specifies the experiment and the stimuli, controls the experiment, delivers the stimuli to the subject through a digital signal processor (DSP) board, collects the responses via a computer mouse or a graphics tablet, and writes the results to the same file. At present, the APEX system is implemented for the LAURA (Registered trademark of Philips Hearing Implants) cochlear implant. However, the concept—and many parts of the system—is portable to any other device. Also, psycho-acoustical experiments can be conducted by presenting the stimuli acoustically through a sound card.
A method for studying variability in fricatives using dynamic measures of spectral mean
Authors: Munson Benjamin
Published: July 2002

This paper presents a new method for studying within-speaker variability in fricative spectra. In this method, nonlinear regression is used to predict values of the spectral mean of a 10-ms window of frication noise from its position in the fricative. The resulting measure of model fit, R2, is used as an index of within-speaker variability. This method was applied to a corpus of /s/ and /∫/ tokens spoken by three groups of participants: 3–4-year-old children, 7–8-year-old children, and adults. Results indicated that fricatives were more variable when produced before the stop consonant /p/ than before /t/. No difference in variability was noted between adults and children, although a nonsignificant trend of decreased variability in adults was noted.
Judgments of noticeable differences in sound fields of concert halls caused by intensity variations in early reflections
Authors: Okano Toshiyuki
Published: July 2002

In concert halls early reflections combine with the direct sound and with reverberation to determine the subjective rating of a room’s acoustics. Of interest is how variations in the amplitudes of these early reflections are related to the subjectively just-noticeable differences (jnd) in several important acoustical parameters for their wide range encountered in existing halls. Investigated were four subjective parameters, apparent source width (ASW), loudness, intimacy and clarity, which are related to the physical measurements, [1—IACCE3], G, ITDG, and C80, defined mathematically in Beranek [Concert and Opera Halls: How They Sound (Acoustical Society of America, New York, 1996)]. Forty-eight types of sound fields were chosen in which to make variations in the amplitudes of early reflections and were reproduced electro-acoustically by multiple loudspeakers in an anechoic chamber. The results indicate that ASW and loudness are more sensitive to changes in the levels of early reflections, and were the primary parameters investigated. Although the number of subjects available with enough experience in listening classical music is limited and the measured jnd is an initial estimation, the jnd of [1—IACCE3] is measured as 0.065±0.015 in variations of sound field structures and the jnd of G was measured as 0.25±0.15 dB, which is consistent with the results of previous studies.
Velocity dispersion in water-saturated granular sediment
Authors: Stoll Robert D.
Published: July 2002

Recent experiments in the Gulf of Mexico have yielded a wealth of information on the environmental conditions and geoacoustic response of a uniform sand stratum immediately beneath the seafloor. A comparison of p-wave velocities measured at low (125 Hz) and high (11–50 kHz) frequencies in this layer indicates that there is a significant amount of velocity dispersion that occurs in the interval between these extremes. This narrow-band dispersion, which is not consistent with the often-used assumption of a nearly constant-Q model, is in accordance with the predictions of the Biot theory. It results from viscous damping in the fluid as it moves relative to the skeletal frame. Other recent field data that support this conclusion are presented.
Frequency specificity of chirp-evoked auditory brainstem responses
Authors: Wegner Oliver , Dau Torsten
Published: July 2002

This study examines the usefulness of the upward chirp stimulus developed by Dau et al. [J. Acoust. Soc. Am. 107, 1530–1540 (2000)] for retrieving frequency-specific information. The chirp was designed to produce simultaneous displacement maxima along the cochlear partition by compensating for frequency-dependent traveling-time differences. In the first experiment, auditory brainstem responses (ABR) elicited by the click and the broadband chirp were obtained in the presence of high-pass masking noise, with cutoff frequencies of 0.5, 1, 2, 4, and 8 kHz. Results revealed a larger wave-V amplitude for chirp than for click stimulation in all masking conditions. Wave-V amplitude for the chirp increased continuously with increasing high-pass cutoff frequency while it remains nearly constant for the click for cutoff frequencies greater than 1 kHz. The same two stimuli were tested in the presence of a notched-noise masker with one-octave wide spectral notches corresponding to the cutoff frequencies used in the first experiment. The recordings were compared with derived responses, calculated offline, from the high-pass masking conditions. No significant difference in response amplitude between click and chirp stimulation was found for the notched-noise responses as well as for the derived responses. In the second experiment, responses were obtained using narrow-band stimuli. A low-frequency chirp and a 250-Hz tone pulse with comparable duration and magnitude spectrum were used as stimuli. The narrow-band chirp elicited a larger response amplitude than the tone pulse at low and medium stimulation levels. Overall, the results of the present study further demonstrate the importance of considering peripheral processing for the formation of ABR. The chirp might be of particular interest for assessing low-frequency information.
Auditory profile analysis: Is there perceptual constancy for spectral shape for stimuli roved in frequency?
Authors: Gockel Hedwig , Colonius Hans
Published: July 2002

The ability to discriminate between two spectral shapes was investigated using a one-interval, two-alternative forced choice procedure. Each stimulus consisted of seven components equally spaced on a logarithmic frequency scale (frequency ratio of 1.2 between adjacent components). The two spectral shapes were produced by first generating a complex each of whose components was equally loud (when heard in isolation) and then increasing the level of either the third or the fifth component by a certain amount. To render pitch an unusable cue, the center frequencies of the stimuli were randomly varied between presentations (maintaining the ratio between adjacent components) over a range of about three octaves (279–2074 Hz). The data indicate that listeners were not able to distinguish between the two types of profiles even for very large increments in level of the third and the fifth components. The results suggest that there is no perceptual constancy for this type of spectral shape for stimuli roved over a sufficiently large frequency range. The spectral shape cannot be perceived independently of stimulus frequency. The results are related to the multi-channel model applied in profile analysis tasks.
Signal response of elastically coated plates
Authors: Keltie Richard F.
Published: July 2002

An analytical model of a compliant elastic coating attached to a submerged thin plate has been developed. A plane acoustic wave, representing the signal, is incident from the water on to the elastic coating. The normal and tangential velocity components induced in the coating by the acoustic wave are calculated. The effects of incidence angle, frequency, location throughout the coating, and coating properties on the signal response velocity components are evaluated. Many details of the coating velocity components are explained based on simple uncoupled waveguide characteristics of the coating. In general, the normal velocity components are several tens of decibels higher in amplitude than the tangential velocity components. It was shown, however, that the tangential velocity component could be increased by an average amount of about 20 dB, without serious degradation of the normal component, by altering the coating properties. In particular, combinations of high longitudinal wave speed and low shear wave speed were found to be advantageous.
Measurements of differential scattering cross section using a ring transducer
Authors: Jansson Tomas T. , Mast T. Douglas , Waag Robert C.
Published: July 2002

A procedure for the measurement of intrinsic scattering object properties is presented and used to obtain illustrative results. The procedure is based on the measurement of the scattered acoustic field as a function of scattering angle and frequency. Measurements are normalized using analytically determined expressions for emitter and detector beams resulting from a combination of unfocused linear elements arranged in a circular configuration. The spatial effects of finite emitter pulse length and detector gate length are represented by a convolution formula valid for narrow-band transmitted signals and long receiver gates. The normalization includes correction for target absorption as well as measurement of the directly transmitted acoustic power in the free field and yields the average differential scattering cross section per unit volume. Under the Born approximation, this quantity is directly proportional to the spatial-frequency spectrum of the scattering medium inhomogeneities. Measured results are reported for two phantoms consisting of glass microspheres embedded in a weakly absorbing agar background medium. For the phantoms employed, scattering effects, rather than increased absorption, are shown to account for most of the difference in transmission loss between pure agar and agar with glass spheres. The measured differential scattering cross sections are compared with theoretical cross sections for distributions of glass spheres measured experimentally. The measured values show good relative agreement with theory for varying angle, frequency, and phantom properties. The results are interpreted in terms of wave space resolution and the potential for tissue characterization using similar fixed transducer configurations.
Three-dimensional mechanical admittance: Theory and new measurement method applied to the violin bridge
Authors: Boutillon Xavier , Weinreich Gabriel
Published: July 2002

The mechanical admittance (or mobility) measures the generalized velocities of a system under generalized forces, whereas the impedance measures the forces when velocities are imposed. It is shown that generally, and in cases of practical interest, the experimental determination of the impedance and that of the admittance must comply with different requirements. Therefore, one description cannot be derived from the other unless the degrees of freedom of the system which are not measured are properly dealt with. Some of the experimental methods presented in the literature are discussed along these lines. A new method is proposed for measuring locally the mobility matrix: it is based on comparison with a known mechanical impedance and requires no force measurements. A realization is presented in the case of the bridge of a violin and a quarter-size cello. Theoretical requirements are found to be met between ∼450–1500 Hz for the violin and ∼250–2000 Hz for the cello. Limitations of the method are found to be the influence of rotational degrees of freedom and the scarcity of modes at some frequencies. Some implications of the findings for the acoustics of the violin are also discussed.
Modulation of torsional waves in a rod with a crack
Authors: Ekimov A. E. , Didenkulov I. N. , Kazakov V. V.
Published: July 2002

Results of experiments concerning nonlinear effects for elastic waves in metal rods with the crack-type defects are presented. The dependence of the nonlinear effect on the contact type is discussed. The crack has been modeled by cutting a rod and tightly filling the crack with metal plates. Two types of contact have been studied: a dry contact and a contact with lubricant. The modulation of high-frequency torsional waves (20 and 22.8 kHz) in the rod under the effect of low-frequency flexural vibrations has been investigated. Flexural vibrations have been excited by a shock and by a vibrator. The modulation of high-frequency torsional waves under the effect of low-frequency vibrations has been observed only in the rod with a crack. The level of modulation drastically decreases in the presence of liquid lubricant.
The use of glottal electromagnetic micropower sensors (GEMS) in determining a voiced excitation function
Authors: Burnett Gregory C. , Holzrichter John F. , Ng Larry C. , Gable Todd J.
Published: July 2002

Recent experiments using a portable, extremely low-power electromagnetic motion sensor to detect the motion of the posterior tracheal wall during speech production will be presented. The motion of the wall may be related to the driving subglottal pressure through a lumped element circuit model, leading to an approximation to the voiced excitation function of the human vocal tract. Using the excitation and the recorded spoken audio, a stable and accurate transfer function of the vocal tract may be calculated every few glottal cycles in near real-time. The excitation function may be used to calculate very accurate pitch information at low cost, and the transfer functions may be employed as an additional feature vector to enhance the performance of a new class of speech recognizers and synthesizers. [Work supported by NSF and DOE.]
Detection of time- and bandlimited increments and decrements in a random-level noise
Authors: Heinz Michael G. , Formby C.
Published: July 2002

The purpose of this study was to compare detection of increments and decrements occurring over limited regions of time and frequency within a 500-ms broadband (0–6000 Hz) noise. Three listeners tracked detection thresholds adaptively in a two-interval, two-alternative forced-choice task. Thresholds were measured for both increments and decrements in level [ΔL=10 log10(1+ΔN0/N0) dB, where N0 is the spectral power density of the noise] as a function of signal duration (T=30–500 ms) for a range of signal bandwidths (W=62–6000 Hz) that were logarithmically centered around 2500 Hz. Listeners were forced to rely on temporal- and spectral-profile cues for detection due to randomization of overall presentation level from interval to interval, which rendered overall energy an inconsistent cue. Increments were detectable for all combinations of W and T, whereas decrements were not consistently detectable for W<500 Hz. Narrow-band decrements were not detectable due to spread of excitation from the spectral edges of the noise into the decrements. Increment and decrement thresholds were similar for W⩾1000 Hz. Temporal- and spectral-integration effects were observed for both increments and decrements. The exceptions were for random-level conditions in which the signal matched the bandwidth or duration of the standard. A multicue decision process is described qualitatively to explain how the combination of temporal- and spectral-profile cues can produce temporal- and spectral-integration effects in the absence of overall-energy cues.
Quantifying the distortion products generated by amplitude-modulated noise
Authors: Wiegrebe Lutz , Patterson Roy D.
Published: July 2002

When sinusoidal amplitude modulation (SAM) is applied to noise or tone carriers, the stimuli can generate audible distortion products in the region of the modulation frequency. As a result, when bandpass-filtered SAM noise is used to investigate temporal processing, a band of unmodulated noise is typically positioned at the modulation frequency to mask any distortion products. This study was designed to investigate the distortion products for bandpass noise carriers, and so reduce ambiguity about the form of this distortion and its role in perception. The distortion consists of two distortion-noise bands and a distortion tone at the modulation frequency. In the first two experiments, the level and phase of the distortion tone are measured using two different experimental paradigms. In the third experiment, modulation-frequency difference limens are measured for filtered SAM noise and it is shown that performance deteriorates markedly when the distortion tone is canceled. In a fourth experiment, masked threshold is measured at low frequencies for bands of high-frequency, unmodulated noise with the same levels and spectra as the SAM noises in the earlier experiments. The results confirm that unmodulated noise also produces quadratic distortion which may explain some aspects of earlier reports on remote masking.
Optimum and standard beam widths for numerical modeling of interface scattering problems
Authors: Stephen Ralph A.
Published: July 2002

Gaussian beams provide a useful insonifying field for surface or interface scattering problems such as encountered in electromagnetics, acoustics and seismology. Gaussian beams have these advantages: (i) They give a finite size for the scattering region on the interface. (ii) The incident energy is restricted to a small range of grazing angles. (iii) They do not have side lobes. (iv) They have a convenient mathematical expression. The major disadvantages are: (i) Insonification of an interface is nonuniform. The scattered field will depend on the location of the scatterers within the beam. (ii) The beams spread, so that propagation becomes an integral component of the scattering problem. A standard beam parameterization is proposed which keeps propagation effects uniform among various models so that the effects of scattering only can be compared. In continuous wave problems, for a given angle of incidence and incident amplitude threshold, there will be an optimum Gaussian beam which keeps the insonified area as small as possible. For numerical solutions of pulse beams, these standard parameters provide an estimate of the smallest truncated domain necessary for a physically meaningful result.
Simulation of circular array ultrasound transducers for intravascular applications
Authors: Borsboom Jerome M. G. , Céspedes E. Ignacio , van der Steen Antonius F. W. , Lancée Charles T. , Deprettere Ed F.
Published: July 2002

The beam shape of a circular array transducer that is commonly used in intravascular ultrasound catheters was investigated in linear mode of operation. For this use, a simulation program which can simulate the radio frequency (rf)-response of a number of scatterers has been developed. The program is based on the impulse response method, which is implemented in the frequency domain. Due to the unusual geometry of the transducer, the far field gets peculiarly shaped for large apertures. Instead of having a far field with its maximum intensity in a single lobe on the acoustical axis, the far field splits up into a dual-lobe far field with maximum intensity in two lobes off the acoustical axis. A formula is derived that predicts the occurrence of these beam shapes.
Elasticity in Steady Flow
Authors: Philippoff W.
Published: July 2002

In rheology the use of the concepts of elasticity—or mechanical stored energy—or recoverable shear in steady flow has been used for some time, but by no means universally accepted. In this paper, the foundations of the statistical mechanics of polymer solutions, as developed by Kuhn, Rouse, and Zimm, together with numerous others, are reviewed for the purpose of developing the basic ideas of elasticity and birefringence in steady flow and investigating what assumptions and limitations the present theory has. The quantitative relations between a number of mathematical theories are tabulated and a survey of the experimental results is given. The questions still unsolved are formulated. Especially the correlation among viscosity, flow birefringence, dynamic properties, and normal stress measurements is emphasized.
Angular Relationship in Rheology
Authors: Philippoff W.
Published: July 2002

Up to now the constitutive equations for viscoelastic liquids have usually been formulated in connecting similar components of the stress and strain velocity tensors (one-dimensional liquids). This is completely adequate if one assumes that both tensors have their axes parallel to each other (coaxial tensors). However, there is enough evidence, especially in finite shear in laminar flow, that this is not always the case. The stress and strain velocity tensors can have a finite angle between their principal axes. This angle in finite shear depends on the amount of shear. In such a case, not only the relation between the corresponding components has to be considered but also the influence of all the components of one tensor on each single component of the other tensor. This has been performed for laminar (two-dimensional) shear for the Maxwell and the Rouse models and results in a non-Newtonian viscosity for both models and a different behavior for the recoverable shear calculated from steady-state and vibrational experiments. The results of the theory coincide closely with experimental findings.
Material Functions for Generalized Newtonian Fluids
Authors: Dealy John M.
Published: July 2002

The concept of the generalized Newtonian fluid (GNF) provides a useful basis for the formulation of constitutive equations for real materials. The purpose of this paper is to review the rational foundations of the generalized Newtonian fluid, and to discuss the problems involved in its practical application to real materials. Of special interest are the types of material constants which must appear and the dimensionless groups which govern the solutions of boundary value problems. It is demonstrated that, if the material function of a GNF contains one material constant with units of viscosity, it must also contain at least one material constant with units of time (or reciprocal time). The role of this characteristic time for both purely-viscous and elastic fluids is discussed.
On the Ultrasonic Dynamic Viscosities in Superposed Oscillatory Shear
Authors: Bernstein B. , Huilgol R. R.
Published: July 2002

The dynamic shear viscosities for both in-line and transverse oscillations, superposed on steady simple shearing, have been measured experimentally. It has been found that at large values of the frequency of oscillation, these dynamic viscosities approach the zero shear dynamic viscosity, measured according to the linear theory of viscoelasticity. It is the purpose of this note to derive these ultrasonic limits by a theoretical study of the incompressible BKZ fluid. It is also shown by a counterexample that these limits do not hold for all simple fluids.
A Layered Waveguide Technique for Determination of the Viscoelastic Properties of Liquids and Deformable Solids
Authors: Hunston Donald L. , Myers Raymond R. , Palmer Maurice B.
Published: July 2002

In connection with the development of a technique for determining shear mechanical properties of liquids and deformable solids at high frequencies, the basic equations are presented for a layered waveguide geometry. The model is an infinite plate surrounded by an infinite viscoelastic material. The propagation of shear waves in such a system is described and the appropriate equations are developed to relate explicitly the shear mechanical properties of the surrounding material to the velocity and attenuation of the wave in the plate. For the case in which the characteristic shear mechanical impedance of the surrounding material is less than 2% of that of the plate, a simplified equation is obtained. This equation is useful for a wide range of liquids. The equations for the layered waveguide technique are compared to the corresponding equations for other techniques and the similarities are discussed.
On Ultrasonic Dynamic Moduli
Authors: Bernstein B. , Huilgol R. R.
Published: July 2002

It had been shown previously that the dynamic viscosities measured by superposing in-line and transverse small-amplitude oscillations on steady simple shearing were independent of the base rate of shear at ultrasonic frequencies in the BKZ fluid. This result was derived on the assumption that the shear relaxation modulus had a bounded right-hand derivative at the origin. The present investigation proves this same result without this assumption. A similar conclusion is derived for the derivative of the storage modulus at high frequencies. In addition, it is shown that these ultrasonic measurements cast light on the question of the boundedness of the first two derivatives of the relaxation modulus at the origin.
X-ray powder diffraction analysis of an organic adduct m-nitrobenzoic acid diethanolamina for nonlinear optics
Authors: Che Yunxia , Zheng Jimin , Hao Jianmin , Chu Lianqing
Published: July 2002

An organic adduct nonlinear optical material m-nitrobenzoic acid⋅diethanolamina (C11H16N2O6) has been characterized by X-ray powder diffraction. Experimental values of 2θ corrected for systematic errors, relative peak intensities, values of d, and the Miller indices of 56 observed reflections are reported. The powder diffraction data have been evaluated, and the figure of merit was found to be F30=57.9 (0.0108, 48). The unit cell parameters were refined by a least-squares fit with a Cc space group and a=22.973(5) Å, b=4.6657(6) Å, c=15.023(3) Å, β =124.45(1)°, V=1327.75 Å3; Z=4, Dx=1.37 g/cm3. The powder diffraction results are in agreement with those obtained from single crystal structure data.
A study on the home modifications required for discharged patients from hospital to home
Authors: Nishino Akiko , Tsukuda Kazunori , Okamoto Kazuhiko , Nishide Kazuhiko
Published: April 2022

The objective of this study is to find out the actual situations of discharged patients' home modifications to mitigate the environmental gap between a recovery rehabilitation hospital and their own homes, as well as to identify their potential needs for home improvement. The results of this study show: (1) Patients have many potential needs for home modification which are hard for a physical therapist (PT) or occupational therapist (OT) to discover at one‐time‐only home inspections 1 month before discharge. (2) The typical suggestion from a PT or OT is to install handrails, whereas architectural experts have limited opportunity to give professional advice; therefore, a collaboration system should be established.
Cost‐Effectiveness of the Early Arthritis Clinic Organizational Model
Authors: Zanetti Anna , Sakellariou Garifallia , Zambon Antonella , Carrara Greta , Argnani Lisa , Mantovani Lorenzo G. , Cortesi Paolo A. , Bugatti Serena , Montecucco Carlomaurizio , Scirè Carlo A.
Published: April 2022

Objective

Early diagnosis and tight control improve outcomes of rheumatoid arthritis (RA). However, whether establishing an early arthritis clinic (EAC) is sustainable for national health systems is not known. This analysis aimed to compare effectiveness and costs of an EAC compared to patients followed by the current standard of care.

Methods

A retrospective study on administrative health databases of patients with a new diagnosis of RA was conducted: 430 patients followed in an EAC were enrolled, and 4 non‐EAC controls were randomly matched for each. During 2 years of follow‐up, the mean health care costs (outpatient, inpatient, pharmaceutical, and global) and 3 effectiveness measures (number and length of hospitalization and quality of care) of the EAC and non‐EAC were estimated. The incremental cost‐effectiveness ratio was calculated as well as the cost‐effectiveness acceptability curve.

Results

The cohorts included patients with a mean age of 55.4 years, and 1,506 patients (70%) were female. The mean pharmaceutical (2,602 versus 1,945 euros) and outpatient (2,447 versus 1,778 euros) costs were higher in the EAC cohort. Conversely, a higher rate of non‐EAC patients had a low adherence to quality‐of‐care indicators. The expected number of hospitalizations and the length of stay were statistically significantly higher in the non‐EAC versus EAC.

Conclusion

Despite an expected increase in outpatient costs (visits and diagnostic tests) and pharmaceutical costs, the reduction in terms of number and length of hospitalizations and the higher adherence to international quality‐of‐care guidelines support the effectiveness of the EAC model.
Impact of Belimumab on Organ Damage in Systemic Lupus Erythematosus
Authors: Urowitz Murray B. , Aranow Cynthia , Asukai Yumi , Bass Damon L. , Bruce Ian N. , Chauhan Deven , Dall'Era Maria , Furie Richard , Fox Norma Lynn , Gilbride Jennifer A. , Hammer Anne , Ginzler Ellen M. , Gonzalez‐Rivera Tania , Levy Roger A. , Merrill Joan T. , Quasny Holly , Roth David A. , Stohl William , van Vollenhoven Ronald , Wallace Daniel J. , Petri Michelle
Published: April 2022

Organ damage is a key determinant of poor long‐term prognosis and early death in patients with systemic lupus erythematosus (SLE). Prevention of damage is a key treatment goal of the 2019 update of the European Alliance of Associations for Rheumatology (EULAR) recommendations for SLE management. Belimumab is a monoclonal antibody that inhibits B lymphocyte stimulator (BLyS) and is the only therapy approved for both SLE and lupus nephritis. Here, we review the clinical trial and real‐world data on the effects of belimumab on organ damage in adult patients with SLE. Across 4 phase III studies, belimumab in combination with background SLE therapy demonstrated consistent reductions in key drivers of organ damage including disease activity, risk of new severe flares, and glucocorticoid exposure compared to background therapy alone. Long‐term belimumab use in SLE also reduced organ damage progression measured by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index, as reported in open‐label extension studies, and propensity score–matched comparative analyses to background therapy alone. Results from a clinical trial showed that in patients with active lupus nephritis, belimumab treatment improved renal response, reduced the risk of renal‐related events, and impacted features related to kidney damage progression compared to background therapy alone. The decrease of organ damage accumulation observed with belimumab treatment in SLE, including lupus nephritis, suggest a disease‐modifying effect.
Nonlinear robust‐optimal control of boost converter in photovoltaic applications
Authors: Amirparast Ali , Gholizade‐Narm Hossein
Published: April 2022

The negative aspects of overusing fossil fuels for producing electricity attract the attention of engineers society to use renewable energies. Power electronic converters play an important role in the transmission and usage of renewable energy in the industry. Boost converters are a major part of devices in which convert renewable energies into usable energy for various industries or appliances. In this article, to control a boost converter with parametric uncertainty, a new robust‐optimal controller is designed. The proposed control method is designed based on merging two conventional control theory: the robust control theory and linear quadratic regulator technique. This method consists of two nested loops. The inner loop composed of a state feedback controller which works as active damping to improve the transient state. The outer loop consists of a PI controller to track the desired voltage and reject disturbance. The coefficients of both controllers are computed by a robust‐optimal control technique. To evaluate the proposed control method, a well‐tuned single‐loop PI controller and a quantitative feedback theory based PID controller are compared with the proposed method. As shown by simulations, the proposed method has a more reliable performance in dealing with parameters uncertainties such as load changes and input voltage drops.
A distributed optimal power management system for microgrids with plug&play capabilities
Authors: Hosseinzadeh Mehdi , Schenato Luca , Garone Emanuele
Published: April 2022

In this article we consider the problem of managing the power flow among different components of a microgrid while ensuring that the demands of all loads are satisfied. In order to address this problem, we propose a distributed scheme where only one sensor (for each subgrid in the microgrid) broadcasts a single scalar variable though a wireless communication network (e.g., WiFi, ZigBee, cellular communication network). More precisely, in the proposed scheme each generation/storage subsystem is able to adjust its operating set‐point only making use of the feedback from the sensors. This architecture provides the system with plug&play capabilities. Interestingly enough, the proposed scheme provides the optimal power flow for the whole microgrid without any information on the demanded load. In this article we apply the proposed approach to hybrid ac/dc microgrids; however, the scheme is general and can be applied to any type of microgrid. The effectiveness of the proposed scheme is evaluated through extensive simulations and compared with a centralized optimal strategy.
Single‐Junction Organic Solar Cells with 19.17% Efficiency Enabled by Introducing One Asymmetric Guest Acceptor
Authors: Sun Rui , Wu Yao , Yang Xinrong , Gao Yuan , Chen Zeng , Li Kai , Qiao Jiawei , Wang Tao , Guo Jing , Liu Chao , Hao Xiaotao , Zhu Haiming , Min Jie
Published: April 2022

The ternary strategy has been widely identified as an effective approach to obtain high‐efficiency organic solar cells (OSCs). However, for most ternary OSCs, the nonradiative voltage loss lies between those of the two binary devices, which limits further efficiency improvements. Herein, an asymmetric guest acceptor BTP‐2F2Cl is designed and incorporated into a PM1:L8‐BO host blend. Compared with the L8‐BO neat film, the L8‐BO:BTP‐2F2Cl blend film shows higher photoluminescence quantum yield and larger exciton diffusion length. Introducing BTP‐2F2Cl into the host blend extends its absorption spectrum, improves the molecular packing of host materials, and suppresses the nonradiative charge recombination of the ternary OSCs. Consequently, the power conversion efficiency is improved up to 19.17% (certified value 18.7%), which represents the highest efficiency value reported for single‐junction OSCs so far. The results show that improving the exciton behaviors is a promising approach to reducing the nonradiative voltage loss and realizing high‐performance OSCs.
Steric Engineering Enables Efficient and Photostable Wide‐Bandgap Perovskites for All‐Perovskite Tandem Solar Cells
Authors: Wen Jin , Zhao Yicheng , Liu Zhou , Gao Han , Lin Renxing , Wan Sushu , Ji Chenglong , Xiao Ke , Gao Yuan , Tian Yuxi , Xie Jin , Brabec Christoph J. , Tan Hairen
Published: April 2022

Wide‐bandgap (WBG, ≈1.8 eV) perovskite is a crucial component to pair with narrow‐bandgap perovskite in low‐cost monolithic all‐perovskite tandem solar cells. However, the stability and efficiency of WBG perovskite solar cells (PSCs) are constrained by the light‐induced halide segregation and by the large photovoltage deficit. Here, a steric engineering to obtain high‐quality and photostable WBG perovskites (≈1.8 eV) suitable for all‐perovskite tandems is reported. By alloying dimethylammonium and chloride into the mixed‐cation mixed‐halide perovskites, wide bandgaps are obtained with much lower bromide contents while the lattice strain and trap densities are simultaneously minimized. The WBG PSCs exhibit considerably improved performance and photostability, retaining >90% of their initial efficiencies after 1000 h of operation at maximum power point. With the triple‐cation/triple‐halide WBG perovskites enabled by steric engineering, a stabilized power conversion efficiency of 26.0% in all‐perovskite tandem solar cells is further obtained. The strategy provides an avenue to fabricate efficient and stable WBG subcells for multijunction photovoltaic devices.
Flexible Confinement and Manipulation of Mie Resonances via Nano Rectangular Hollow Metasurfaces
Authors: Li Zhancheng , Geng Guangzhou , Cheng Jiaqi , Liu Wenwei , Yu Shiwang , Xie Boyang , Cheng Hua , Li Junjie , Zhou Wenyuan , Tian Jianguo , Chen Shuqi
Published: April 2022

Mie resonances excited in high‐index all‐dielectric metasurfaces provide a powerful platform for the constraint and manipulation of light at the subwavelength scale, which enable tremendous advanced developments in optical field manipulation, imaging, and sensing. Recently, how to manipulate and confine Mie resonances in the frequency domain has attracted tremendous interest since it is invaluable for the implementation of frequency‐selective and ‐multiplexed optical devices. Here, the authors theoretically analyze and experimentally demonstrate that the nano rectangular hollow (NRH) metasurfaces are promising candidates for the flexible confinement and effective manipulation of Mie resonances in the frequency domain. They reveal that the diameter of the hollow in the NRH can provide an efficient degree of freedom for the constraint of displace currents in the space domain, which results in the confinement of Mie resonances in the frequency domain. The excitation wavelength of the Mie resonance can also be manipulated by adjusting the side length of the NRH. The potential uses of NRH metasurfaces in the implementation of frequency‐selective intensity encoding and optical encryption are theoretically and experimentally demonstrated. The results provide a fertile ground for confining Mie resonances in the frequency domain and can be further applied in frequency‐multiplexed optical devices.
Facile Polydimethylsiloxane Treatment of Indium Gallium Zinc Oxide Phototransistor for Visible Light‐Based Multilevel Photomemory
Authors: Park Kyungho , Lee Jin Hyeok , Kang Byung Ha , Chung Jusung , Kim Hee Jun , Kwak Kyungmoon , Kim Hyun Jae
Published: April 2022

For visible light‐based multilevel photomemories, indium‐gallium‐zinc‐oxide (IGZO, In:Ga:Zn = 1:2.8:1.4)‐based phototransistors capable of detection and storage in the visible light region are fabricated through the facile polydimethylsiloxane (PDMS) treatment, a process of exfoliating the hardened PDMS after coating on the gate insulator (GI) via a drop‐casting process. Here, PDMS residues form on the GI by exfoliation induced subgap states in the front channel of IGZO. Subgap states are composed of interface trap states by the less‐hardened PDMS and organic‐related trap states by diffusion of organic residues into the IGZO front region during the 300 °C annealing step. PDMS‐treated IGZO phototransistors exhibit improved optoelectronic characteristics due to increased subgap states. Photoresponsivity, photosensitivity, and detectivity under red light irradiation with an intensity of 5 mW mm−2 are improved compared with untreated IGZO phototransistors, from 69.56 to 718.15 A W−1, from 7.64 × 103 to 4.63 × 107, and from 3.16 × 108 to 1.25 × 1012 Jones, respectively. Additionally, the possibility of multilevel photomemory is evaluated using the same devices. These devices are able to not only hold data for 18 000 s after red light irradiation for 1 s but also exhibit stable operation for up to 60 repetitive programming/erasing cycles.
Hypertension, a dementia polygenic risk score, APOE genotype, and incident dementia
Authors: Littlejohns Thomas J. , Collister Jennifer A. , Liu Xiaonan , Clifton Lei , Tapela Neo M. , Hunter David J.
Published: April 2022

Introduction

There is inconsistent evidence on whether genetic risk for dementia modifies the association between hypertension and dementia.

Methods

In 198,965 dementia‐free participants aged ≥60 years, Cox proportional‐hazards models were used to investigate the association between hypertension and incident dementia. A polygenic risk score (PRS) based on 38 non‐apolipoprotein E (APOE) single nucleotide polymorphisms and APOE ε4 status were used to determine genetic risk for dementia.

Results

Over 15 years follow‐up, 6270 participants developed dementia. Hypertension was associated with a 19% increased risk of dementia (hazard ratio = 1.19, 95% confidence interval 1.11–1.27). The associations remained similar when stratifying by genetic risk, with no evidence for multiplicative interaction by dementia PRS (P = 0.20) or APOE ε4 status (P = 0.16). However, the risk difference between those with and without hypertension was larger among those at higher genetic risk.

Discussion

Hypertension was associated with an increased risk of dementia regardless of genetic risk for dementia.
Validating the trauma care system developed by Yokohama City local government
Authors: Takeuchi Ichiro , Morimura Naoto , Iwashita Masayuki , Kitano Mitsuhide , Doi Tomoki , Hayashi Munetaka , Fujita Takashi , Yamasaki Motoyasu , Shuri Jun
Published: April 2022

Background

Since becoming the city with the first government‐designated major trauma center in 2014, Yokohama has been striving to centralize care for extensive trauma patients. Hence, in this study, the Yokohama City Major Trauma Care Advisory Committee tested the efficacy of the centralization of care for trauma patients.

Methods

This investigation included all cases of deaths due to road traffic accidents that occurred in the 2‐year period following the establishment of the major trauma center. The probability of survival was calculated using data provided by the police and fire departments. Cases that died despite having a probability of survival of 50% or more were included in the survey undertaken by physicians recommended by the Japanese Association for the Surgery of Trauma, who visited the hospitals.

Results

Of those surveyed, preventable trauma death accounted for 1 case (1.7%) and potentially preventable trauma death accounted for 7 (11.9%), compared with 5 (9.8%) and 11 (21%) cases, respectively, in the period 2009–2010.

Conclusions

Comparing the survey conducted before establishment of the major trauma center, those results support the benefits of centralizing care for severe trauma cases. We aim to continue improving trauma care provided through the center along with the Yokohama Medical Control Council and to overcome challenges that were identified through the peer review.