bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of seed loading approaches in prostate brachytherapy
Authors: Butler Wayne M. , Merrick Gregory S. , Lief Jonathan H. , Dorsey Anthony T.
Published: July 2002

Since uniform seed loading in prostate brachytherapy can produce an intolerably high dose along the urethra, some form of peripheral loading is commonly employed. We define three variants of peripheral loading and compare them in a small, medium, and large prostate in terms of coverage of the planning target volume (PTV), homogeneity, and ability to spare critical structures of excessive dose. Modified uniform loading has at least 2/3 of the seeds occupying sites on a 1 cm cubic grid keyed to the prostate base and the posterior border of the prostate. Nonuniform loading explicitly spares the urethra by using only basal and apical seeds in at least two centrally located needles. Peripheral loading uses higher activity seeds with the posterior implant plane 5 mm anterior to the posterior border of the prostate. The three prostate volumes (18.7, 40.7, and 60.2 cm3 by ultrasound) were expanded to planning volumes (32.9, 60.0, and 87.8 cm3, respectively). The planning volumes (PTVs) were loaded with a seed distribution and activity sufficient to cover 99.7±0.3% of the PTV with the prescribed minimal peripheral dose (mPD) of 145 Gy. Activities used ranged from 0.32 to 0.37 mCi/seed (0.41–0.47 U/seed) for the first two approaches and from 0.57 to 0.66 mCi (0.72–0.84 U) for peripheral loading. Modified uniform loading produced the most uniform distribution based on dose–volume histograms and the volume receiving >150% of prescribed dose. All the approaches are capable of constraining the superior–inferior dose profile (the urethral path) to less than 150% of the mPD, but the nonuniform approach with explicit urethral sparing kept the urethral dose below 120% of the mPD. Dose profiles for the three approaches along the posterior–anterior midline axis are comparable near the urethra, but peripheral and nonuniform approaches have extended regions where the dose is >150% of mPD. These regions approach within 10 mm of the rectum or urethra, so these two approaches require greater accuracy in intraoperative execution of the plan. Although each of the three planning approaches can achieve the treatment goals of adequate coverage and critical structure sparing, modified uniform loading has a more homogeneous dose distribution. This approach may be more forgiving of systematic errors in seed placement.
Demonstration of different bending profiles of a cantilever caused by a torque or a force
Authors: Höpfl Th. , Sander D. , Kirschner J.
Published: July 2002

A simple experiment is described to demonstrate the different deflected shapes assumed by a cantilever due to a torque or a force acting on its end. An optical deflection technique is used to show that different shapes appear in the cantilever even if the torque or force causes an identical displacement of the cantilever end.
Statistical thermodynamics of helix–coil transitions in biopolymers
Authors: Bloomfield Victor A.
Published: July 2002

Helical conformations, such as the α-helix in polypeptides and the double helix in DNA, are common structural elements in biopolymers. As the temperature is raised or the pH is changed to extremes of acidity or alkalinity, the helix becomes disordered into a random coil state. The helix–coil transition has been extensively studied, both experimentally and theoretically, as a model for conformational transitions in biopolymers and as a way to obtain information about the intermolecular forces which stabilize biopolymer structure. We develop three theoretical treatments that describe the helix–coil transition with increasing degrees of detail and rigor: the all-or-none model, the zipper model, which allows initiation of the helix only once along the polymer chain, and the matrix model, which places no restrictions on helix–coil junctions. The matrix model is mathematically similar to the familiar one-dimensional Ising model.
Note on group velocity and energy propagation
Authors: Bers Abraham
Published: July 2002

A general proof is given for the equality between group velocity and energy velocity for linear wave propagation in a homogeneous medium with arbitrary spatial and temporal dispersion.
Spatially extended sound equalization in rectangular rooms
Authors: Santillán Arturo O.
Published: July 2002

The results of a theoretical study on global sound equalization in rectangular rooms at low frequencies are presented. The zone where sound equalization can be obtained is a continuous three-dimensional region that occupies almost the complete volume of the room. It is proved that the equalization of broadband signals can be achieved by the simulation of a traveling plane wave using FIR filters. The optimal solution has been calculated following the traditional least-squares approximation, where a modeling delay has been applied to minimize reverberation. An advantage of the method is that the sound field can be estimated with sensors placed in the limits of the equalization zone. As a consequence, a free space for the listeners can be obtained.
A boundary diffraction wave model for a spherically focused ultrasonic transducer
Authors: Schmerr, Jr. Lester W. , Sedov Alexander , Lerch Terence P.
Published: July 2002

A model of a spherically focused piston transducer is developed in terms of boundary diffraction waves. The model represents the radiated pressure in terms of a direct wave and a one-dimensional edge wave integral. This decomposition allows the efficient calculation of the transducer beam in a form previously available only for a planar transducer. Numerical results for the simulation of the entire wave field of a transducer are given to illustrate the effectiveness of the formulation.
An empirical relation to predict ultrasonic velocity in electrolytic solutions
Authors: Iyer S. Sivaramakrishna , Abdulkhadar M.
Published: July 2002

An empirical relation to predict ultrasonic velocity in an electrolytic solution in terms of the surface tension and density of and ultrasonic velocity in water and surface tension, density and a function f(α) of degree of dissociation of the solution is suggested. The relation may be used to predict ultrasonic velocity at any concentration of the solution, provided the ultrasonic velocities at two other concentrations are known. The agreement between the predicted and observed values is good.
Measurements of scaling properties for acoustic propagation in a single pore
Authors: Wilen L. A.
Published: July 2002

An experimental investigation of sound propagation in a single pore of circular cross section is described. By working at low frequencies and in various pressure ranges, viscous and thermal penetration depths which range from less than, to much greater than, the pore radius are achieved. The system is an experimental model for a pore in either sound absorbing material or the “stack” region of a thermoacoustic engine. The measured acoustic response compares favorably with theoretical predictions. Deviations are attributed to the cell geometry. In certain ranges of pressure and frequency, simple scaling properties may be utilized to determine the relative viscosity and thermal diffusivity of gases. Measurements of both quantities (relative to those of argon) for helium, neon, nitrogen, krypton, and water vapor (viscosity only) are presented and compared with known values. Practical applications of the experimental technique are discussed.
Articulatory control of phonological vowel length contrasts: Kinematic analysis of labial gestures
Authors: Hertrich Ingo , Ackermann Hermann
Published: July 2002

The present study investigated the articulatory control of the German vowel quantity contrast, i.e., the phonological difference between short and long vowels. By means of an optoelectronic system the excursions of the compound lower lip/jaw opening and closing gestures were measured during production of test sentences comprising the target sequence /pVp/ (V=/a/, /i/, /u/, /a:/, /i:/, /u:/). First, a highly linear relationship between peak velocity and movement amplitude emerged within each quantity class. Second, vowel quantity systematically influenced the scaling of velocity and amplitude during oral opening. Third, as compared to their short counterparts, long vowels showed an increased peakedness of the velocity profile. Finally, the velocity profiles of the long vowels were characterized by an asymmetric shape in terms of a prolonged deceleration phase of the opening and a lengthened acceleration interval of the closing movement. With respect to durational coarticulation patterns, the control of vowel quantity clearly differed from intrinsic, i.e., vowel type-induced, variability. The latter was partially compensated for at the level of word duration by shortening of the prevocalic consonant whereas vowel quantity turned out to be primarily due to the lengthening of the syllable /pV/.
Effects of air conditioning on sound propagation in a large space
Authors: Ueda Yasutaka , Ando Yoichi
Published: July 2002

Sound-pressure level (SPL) fluctuation caused by air conditioners is measured using pure tones as the sound source, in a gymnasium. When the air conditioner is turned on, the mean standard deviation of SPL changes about 0.9 dB at 2 kHz, 2.5 dB at 4 kHz, 3.3 dB at 8 kHz, and 3.8 dB at 16 kHz, while that in the case with air conditioning off is less than 0.6 dB at all frequencies. The cumulative density of mean-squared amplitude corresponds well with the gamma distribution. Based on this statistical analysis, the SPL change is thought to be related to the impulse response which is represented by the direct sound (regular) and changing delay time of reflection sound (irregular). The cumulative density of mean-squared amplitude for this model using pure tones also indicated a gamma distribution. It is found that the frequency characteristic and the cumulative density of the SPL change have the same tendencies as the method of modulation for the delay time of reflected sound.
A computationally efficient alternative for the Liljencrants–Fant model and its perceptual evaluation
Authors: Veldhuis Raymond
Published: July 2002

An alternative for the Liljencrants–Fant (LF) glottal-pulse model is presented. This alternative is derived from the Rosenberg model. Therefore, it is called the Rosenberg++ model. In the derivation a general framework is used for glottal-pulse models. The Rosenberg++ model is described by the same set of T or R parameters as the LF model but it has the advantage over the LF model that it is computationally more efficient. It is compared with the LF model in a psychoacoustic experiment, from which it is concluded that in a practical situation it is capable of producing synthetic speech which is perceptually equivalent to speech generated with the LF model.
Vibroacoustic analysis of an unbaffled rotating disk
Authors: Côté André F. , Atalla Noureddine , Guyader Jean-Louis
Published: July 2002

The dynamic and acoustic response of an unbaffled rotating disk, subjected to a space-fixed harmonic lateral force, is investigated. The plate is supposed to be clamped at the inside and free at the outer boundary. The exciting force being space-fixed, the mass and stiffness matrices, obtained from the variational method combined with the Rayleigh–Ritz approach in the rotating frame, are converted back to the nonrotating frame, where the generalized force and the displacements of the plate are evaluated. The related acoustic pressure, neglecting fluid loading, is determined using a boundary element formulation. Special attention has been given to ensure correct modeling of the unbaffled condition on the radiation of the plate. Results are presented to show the effect of rotation for both dynamic response and acoustic radiation. A practical case is also investigated: the circular saw. To simulate the exciting force of the saw, a measurement of the force induced by one tooth has been done. Then, a retarded-time sum has been performed to account for the exact number of teeth.
Gas-filled liposomes as ultrasound contrast agents for blood pool, thrombus-specific and therapeutic applications
Authors: Unger Evan C. , McCreery Thomas , Shen Dekang , Wu GuanLi , Sweitzer Robert , Wu Qui
Published: July 2002

Our group has developed technology for stabilizing microbubbles with phospholipid coatings (Aerosomes®-ImaRx Pharmaceutical Corp.). The first agent (MRX-115) is based upon lipid-coated microspheres filled with perfluoropropane gas and is in phase III clinical trials (October, 1997) for radiology and cardiology applications. Myocardial perfusion studies show the potential for the agent to detect ischemia in patients with myocardial infarcts. Targeting ligands have been covalently bound to lipids and incorporated into the stabilizing shells on the microbubbles. The first targeted agent planned for clinical trials is MRX-408 (perfluorobutane gas, linear hexapeptide-RGD analog). In vitro studies show enhanced visualization of thrombi, and in vivo studies in dogs with arterial and venous thrombi show selective enhancement, even in animals injected with heparin. In vitro studies have been performed to test sonothrombolysis comparing MRX-115 to MRX-408 with and without urokinase. The targeted contrast agent MRX-408 increases the rate of clot dissolution with ultrasound. Targeted, tissue-specific agents are feasible for ultrasound. A thrombus-specific ultrasound contrast agent has the potential to improve clot characterization and detection as well as clot lysis.
Laboratory target strength measurements of free-swimming Antarctic krill (Euphausia superba)
Authors: Pauly Timothy , Penrose John D.
Published: July 2002

Target strength measurements of free-swimming krill at 120 kHz were made using a single-beam monostatic system in a 10-m3 laboratory tank. Krill (grouped according to length classes) swam freely in the tank triggering a data acquisition system when generating a backscattered signal larger than a threshold, determined by the system noise level. Dorsal and ventral target strength estimates were calculated indirectly by deconvolution of the cumulative probability function of echo ensembles of single-animal insonifications. For mean length classes in the range [29.6 to 36.2] mm the median single-animal target strengths are in the range [−76.7 to −71.8] dB. Monte Carlo computer simulations were used to evaluate the effects of varying the ratio of largest to smallest echo amplitudes for a given ensemble, thus enabling the estimation of threshold induced bias in the target strength estimates. The threshold induced bias was then determined for each ensemble of experimental data and used to determine corrections which were in the range of [−0.84 to −0.33] dB. An error analysis of the target strength estimates detailing the components due to measurement accuracy and precision, and the indirect signal processing techniques used is also presented.
An active noise control algorithm for controlling multiple sinusoids
Authors: Lee Seung Man , Lee Hyuck Jae , Yoo Cha Hee , Youn Dae Hee , Cha Il Whan
Published: July 2002

The filtered-x LMS algorithm and its modified versions have been successfully applied in suppressing acoustic noise such as single and multiple tones and broadband random noise. This paper presents an adaptive algorithm based on the filtered-x LMS algorithm which may be applied in attenuating tonal acoustic noise. In the proposed method, the weights of the adaptive filter and estimation of the phase shift due to the acoustic path from a loudspeaker to a microphone are computed simultaneously for optimal control. The algorithm possesses advantages over other filtered-x LMS approaches in three aspects: (1) each frequency component is processed separately using an adaptive filter with two coefficients, (2) the convergence parameter for each sinusoid can be selected independently, and (3) the computational load can be reduced by eliminating the convolution process required to obtain the filtered reference signal. Simulation results for a single-input/single-output (SISO) environment demonstrate that the proposed method is robust to the changes of the acoustic path between the actuator and the microphone and outperforms the filtered-x LMS algorithm in simplicity and convergence speed.
Single-bubble sonoluminescence: Investigation of the emitted pressure wave with a streak camera and a fiber-optic probe hydrophone
Authors: Pecha R. , Wang Z. Q. , Gompf B. , Eisenmenger W.
Published: July 2002

In the collapse end phase of single-bubble sonoluminescence (SBSL), in addition to a short light pulse, a spherical pressure wave is emitted by the bubble into the surrounding liquid. This pressure wave was investigated with two different methods: (1) If the bubble is illuminated by a laser beam, laser light is Mie-scattered by the bubble itself, but also by the outgoing pressure pulse. The scattered light of both was recorded with a streak camera with a spatial resolution of 8 μm and a temporal resolution of 500 ps. From the time-dependent radial distance of the pressure pulse r(t) from the bubble, the velocity v(t) can be determined. The speed of sound in the vicinity of the bubble is increased in comparison to normal conditions. This change in the sound velocity was used to estimate the amplitude of the pressure pulse. (2) At a distance of 2.5 mm from the bubble, a fiber-optic probe hydrophone with a spatial resolution of 100 μm and a rise time of 5 ns was used to measure the pressure wave. Measurements depending on the amplitude of the driving sound field, the gas concentration, and the temperature of the water will be presented.
Sperm whale clicks and the Norris/Harvey theory of click generation
Authors: Mo/hl Bertel
Published: July 2002

In Odontocetes, sounds are generated within the melon, a structure homologous with the nose of terrestrial mammals. In sperm whales this nose is hypertrophied, accounting for about 1/3 of the length or weight of adults. A sound-generating function has been ascribed to this organ complex [K. S. Norris and G. W. Harvey, in NASA Spec. Publ. 262, edited by S. R. Galler et al. (1972), pp. 397–417]. A sound generator weighing upward of 10 tonnes and with a cross section of 2 m is expected to generate high level, directional sounds. This prediction is not supported by the published data for sperm whale clicks (SL’s of 180 dB re: 1 μPa; little, if any, directionality). Such data, if truly characterizing sperm whale clicks, does not support the Norris/Harvey theory. To increase the amount of data, a hydrophone array, suspended from three platforms separated by 1 km and linked by radio, was deployed at the slope of the continental shelf off Andenes, Norway, in the summers of 1997 and 1998. The SL’s above 210 dB re: 1 μPa were recorded. Also, SL differences exceeding 20 dB for the same click at different directions were seen. Thus, previously published properties of sperm whale clicks underestimate maximum capabilities of the sound generator and therefore cannot falsify the Norris/Harvey theory. [Work supported by the Danish National Research Foundation.]
The full-field equations for acoustic radiation and scattering
Authors: Ochmann Martin
Published: July 2002

The source simulation technique or related approaches like the multipole method, the superposition method, etc. are used for calculating the sound field radiated (or scattered) from complex-shaped structures. However, it is known that these techniques can lead to ill-conditioned systems of equations, and their numerical treatment requires extreme care. A new stabilized variant of the source simulation technique—called the full-field method—has been developed by using the exterior instead of the interior Helmholtz integral formulation or, equivalently, by expanding the sound field into special trial and weighting functions. These functions are chosen in such a way that the resulting matrix becomes more diagonally dominant. The full-field method is applied to the acoustic radiation from a pulsating sphere and to the high-frequency scattering from a cylinder and a nonconvex structure. The numerical results are compared with calculations obtained from other methods. It is shown that the improved method leads to better conditioned sets of equations which can be solved directly without singular-value decomposition, since the associated condition numbers are decreased strongly, in some cases by a few orders of magnitude.
Development of dispersion curves for two-layered cylinders using laser ultrasonics
Authors: Kley Markus , Valle Christine , Jacobs Laurence J. , Qu Jianmin , Jarzynski Jacek
Published: July 2002

In this paper, laser-ultrasonic techniques are employed to develop a quantitative understanding of the underlying principles of the propagation of guided circumferential waves in two-layered cylindrical components. The high-fidelity, broad-bandwidth, point source/receiver and noncontact nature of these optical techniques are critical elements to the success of this work. The experimental procedure consists of measuring a series of transient, circumferentially propagating waves in a cylindrical waveguide and then operating on these transient waveforms with signal-processing techniques to develop the dispersion relationship for that waveguide; this procedure extracts the steady-state behavior from a series of transient measurements. These dispersion curves are compared to theoretical values. There is good agreement between the experimental and theoretical results, thus demonstrating the accuracy and effectiveness of using laser-ultrasonic techniques to study the propagation of guided circumferential waves.
Field study of the annoyance of low-frequency runway sideline noise
Authors: Fidell Sanford , Silvati Laura , Pearsons Karl , Lind Stephen , Howe Richard
Published: July 2002

Noise from aircraft ground operations often reaches residences in the vicinity of airports via grazing incidence paths that attenuate high-frequency noise more than air-to-ground propagation paths, thus increasing the relative low-frequency content of such noise with respect to overflight noise. Outdoor A-weighted noise measurements may not appropriately reflect low-frequency noise levels that can induce potentially annoying secondary emissions inside residences near runways. Contours of low-frequency noise levels were estimated in a residential area adjacent to a busy runway from multi-site measurements of composite maximum spectra of runway sideline noise in the one-third octave bands between 25 and 80 Hz, inclusive. Neighborhood residents were interviewed to determine the prevalence of annoyance attributable to runway sideline noise at frequencies below 100 Hz, and of its audible manifestations inside homes. Survey respondents highly annoyed by rattle and vibration were concentrated in areas with low-frequency sound levels due to aircraft operations in excess of 75 to 80 dB.
Calculations of internal-wave-induced fluctuations in ocean-acoustic propagation
Authors: Flatté Stanley M. , Rovner Galina
Published: July 2002

Variability in the ocean sound-speed field on time scales of a few hours and horizontal spatial scales of a few kilometers is often dominated by the random, anisotropic fluctuations caused by the internal-wave field. Results have been compiled from analytical approaches and from numerical simulations using the parabolic approximation into an efficient set of algorithms for calculating approximations to internal-wave effects on temporal and spatial coherences, coherent bandwidths, and regimes of acoustic fluctuation behavior. These approximate formulas account for the background, deterministic, sound-speed profile and the anisotropy of the internal-wave field, and they also allow for the incorporation of experimentally determined profiles of sound speed, buoyancy frequency, and sound-speed variance. The algorithms start from the geometrical-acoustics approximation, in which the field transmitted from a source can be described completely in terms of rays whose characteristics are determined by the sound speed as a function of position. Ordinary integrals along these rays provide approximations to acoustic-fluctuation quantities due to the statistical effects of internal waves, including diffraction. The results from the algorithms are compared with numerical simulations and with experimental results for long-range propagation in the deep ocean.
Laser Doppler velocimetry measurements of particle velocity fluctuations in a concentrated suspension
Authors: Shapley Nina C. , Armstrong Robert C. , Brown Robert A.
Published: July 2002

Recent statistical constitutive models of suspensions of neutrally buoyant, noncolloidal, solid spheres in Newtonian fluids suggest that the particles migrate in response to gradients in “suspension temperature,” defined as the average kinetic energy contained in the particle velocity fluctuations. These models have not yet been compared systematically with experimental data. In addition the “temperature'’ models assume isotropic particle velocity fluctuations, since the suspension temperature is given as a scalar. However, highly anisotropic particle velocity fluctuations have been observed experimentally, which suggests that a suspension temperature tensor is more realistic. We use laser Doppler velocimetry to measure particle velocity fluctuations arising from interparticle collisions in a concentrated suspension under nearly homogeneous shear flow in a narrow-gap concentric cylinder Couette device. We compare the relative sizes of the fluctuating velocity components and determine the variation of each component with particle volume fraction and shear rate. The data indicate that the suspension temperature is anisotropic. The flow direction component is overwhelmingly the largest at every concentration and shear rate, followed in order of magnitude by the neutral-direction and velocity-gradient-direction components. Additionally, over the region of the flow accessible to measurement, each fluctuating velocity component demonstrates a distinct variation with shear rate and particle volume fraction. Finally, we explain the observed anisotropy and variation of the suspension temperature in terms of the dynamics of interparticle interactions.
A Bubble Inflation Technique for the Measurement of Viscoelastic Properties in Equal Biaxial Extensional Flow
Authors: Joye Donald D. , Poehlein Gary W. , Denson Costel D.
Published: July 2002

A bubble inflation technique for establishing equal biaxial extensional flow in viscoelastic materials is presented. This technique was used to measure biaxial extensional viscosity and elastic properties of a polyisobutylene at room temperature (23°C). A theoretical experimental procedure, based on certain idealizations, was developed for establishing bubble growth under constant stress. Modifications of the experimental design were introduced to correct for the nonidealities encountered in practice. The accuracy and reliability of the measurements are tested, and sources of error, and possibilities for future work are discussed. Several constitutive equations are examined with respect to biaxial extensional flow. Predicted behavior patterns are compared with experimental results.
Nonlinear Behavior of Viscoelastic Materials. II. The Method of Analysis and Temperature Dependence of Nonlinear Viscoelastic Functions
Authors: Matsumoto Takayoshi , Segawa Yasuhiko , Warashina Yoshiro , Onogi Shigeharu
Published: July 2002

The nonlinear viscoelastic functions G1′, G1″, G3′, and G3″ were evaluated for disperse systems of polystyrene solution and styrene-divinyl benzene copolymer particles at various temperatures ranging from 10 to 70°C over the frequency range from 12 to 1/256 Hz. In general, frequency dependence curves of all the functions are rather flat and become less sensitive to temperature as the temperature rises. To the curves at different temperatures, the so-called time-temperature superposition can be applied; the shift factors determined in the course of horizontal shifts of curves for various functions are quite the same and are independent of the strain amplitude. Master curves of the nonlinear functions manifest plateaus in the low frequency region, where the polymer solution itself shows rapid changes in G′ and G″. The height of the plateaus increases very rapidly with increasing particle content. All the moduli G1′, G1″, G3′, and G3″ decreases first rapidly and then slowly with increasing strain amplitude until they level off at larger strain amplitudes. The physical meanings of the nonlinear functions are also discussed.
What’s wrong with the moduli Charley Brown? or Get the H out and go to L
Authors: Plazek Donald J.
Published: July 2002

For unknown psychological reasons, the vast majority of viscoelastic measurements are presented as dynamic or stress relaxation modulus functions. To examine only modulus functions appears to be acceptable, because within a constant or two, all of the complete viscoelastic functions are mathematically equivalent. It is pointed out here, that most data are not practicably equivalent and that in numerous instances the compliance functions are more revealing concerning molecular orientational dynamics; especially those that are not influenced by viscous flow. The presence of shoulders or plateaus exhibited by the dynamic storage modulus G′ or the stress relaxation modulus G(t) functions, which can be mistaken for molecular entanglement plateaus, are shown to be present in some systems that contain no effective entanglements. The obfuscation caused by the viscous deformation in the terminal zone of behavior is emphasized. The additivity of different molecular mechanisms contributing to the compliance functions demand that decomposition be carried out on these functions, before further analysis is possible. Since the results from any dynamic measurement, which yields both storage and loss components of the modulus, can be algebraically transformed into the compliance components, investigators have nothing to lose but possibly much to gain by including the examination of the compliances as well as the moduli.
On consistency criteria for stress tensors in kinetic theory models
Authors: Schieber Jay D. , Öttinger Hans Christian
Published: July 2002

Two different consistency criteria are considered for the stress tensor expressions of two different kinetic theory models for dilute polymer solutions. The criteria are material objectivity and thermodynamic consistency. Two separate approaches for checking thermodynamic consistency are considered, the first proposed by Grmela [Phys. Lett. 111A, 41 (1985)] and the second by Jongschaap [Lecture Notes in Physics (Springer, Berlin, 1991)]. The two models considered are a Hookean dumbbell model with internal viscosity (no linearization or rotation matrix approximations), and an inertial, elastic bead-spring chain. Both sets of criteria may be applied to these models without finding either a closed-form expression for the stress tensor, or solving any of the equations. We find that the Giesekus form for the stress tensor expression for a Hookean dumbbell with internal viscosity is both thermodynamically consistent and objective, whereas the Kramers form is not thermodynamically consistent. The Kramers form for the stress tensor is found to be thermodynamically consistent for an inertial, elastic bead-spring chain, but is not materially objective. We also find that the approaches of Grmela and Jongschaap are the same, although each requires a different ansatz for the relationship between thermodynamic quantities and polymer conformations.
Flow development of Herschel–Bulkley fluids in a sudden three-dimensional square expansion
Authors: Burgos Gilmer R. , Alexandrou Andreas N.
Published: July 2002

The flow development of Herschel–Bulkley fluids in a sudden three-dimensional square expansion is studied numerically. The flow is modeled using the mixed-Galerkin finite element formulation to solve the conservation of mass and momentum equations. The Herschel–Bulkley material behavior is described using a regularized model based on the Papanastasiou model. Solutions are obtained for a downstream-to-upstream expansion ratio of 2:1 and for a wide range of pressure gradient values and rheological parameters. The results show that, during the evolution of the flow, two core regions and dead zones at the corners are formed. The extent of the core regions decreases with the pressure gradient and the Reynolds number, and increases with the power-law index. It is also found that the volume flow rate at steady flow increases with the pressure gradient, power-law index, and Reynolds number.
24.64%‐Efficiency MA‐Free Perovskite Solar Cell with Voc of 1.19 V Enabled by a Hinge‐Type Fluorine‐Rich Complex
Authors: Li Zhijun , Wu Meizi , Yang Lu , Guo Kunpeng , Duan Yuwei , Li Yong , He Kun , Xing Yifan , Zhang Zheng , Zhou Hui , Xu Dongfang , Wang Jungang , Zou Hong , Li Da , Liu Zhike
Published: January 2023

High density of defects at interface severely affects the performance of perovskite solar cells (PSCs). Herein, cobalt (II) hexafluoro‐2,4‐pentanedionat (CoFAc), a hinge‐type fluorine‐rich complex, is introduced onto the surface of formamidinium cesium lead iodide (FACsPbI3) film to address the issues of perovskite/Spiro‐OMeTAD interface. The existence of CoFAc passivates both organic cation and halide anion vacancies by establishing powerful hydrogen bonds with HC(NH2)2+ (FA+) and strong ionic bonds with Pb2+ in perovskite films. In addition, CoFAc serves as a connecting link to enhance interfacial hole‐transport kinetics via interacting with Spiro‐OMeTAD. Consequently, FACsPbI3 PSCs with CoFAc modification display a champion power conversion efficiency (PCE) of 24.64% with a charming open‐circuit voltage (VOC) of 1.191 V, which is the record VOC among all the reported organic‐inorganic hybrid PSCs with TiO2 as electron transport layer. Furthermore, CoFAc‐modified devices exhibit an outstanding long‐term stability, which can maintain 95% of their initial PCEs after exposure to ambient atmosphere for 1500 h without any encapsulation.
Dislocated Bilayer MOF Enables High‐Selectivity Photocatalytic Reduction of CO2 to CO
Authors: Liang Jinxia , Yu Hao , Shi Junjuan , Li Bao , Wu Lixin , Wang Ming
Published: January 2023

The highly selective photoreduction of CO2 into valuable small‐molecule chemical feedstocks such as CO is an effective strategy for addressing the energy crisis and environmental problems. However, it remains a challenge because the complex CO2 photoreduction process usually generates multiple possible products and requires a subsequent separation step. In this paper, 2D monolayer and bilayer porphyrin‐based metal‐organic frameworks (MOFs) are successfully constructed by adjusting the reaction temperature and solvent polarity with 5,10,15,20‐tetrakis(4‐pyridyl)porphyrin as the light‐harvesting ligand. The bilayer MOF is a low‐dimensional MOF with a special structure in which the upper and lower layers are arranged in dislocation and are bridged by halogen ions. This bilayer MOF exhibits 100% ultra‐high selectivity for the reduction of CO2 to CO under simulated sunlight without any cocatalyst or photosensitizer and can be recycled at least three times. The intrinsic mechanism of this photocatalytic CO2 reduction process is explored through experimental characterization and density functional theory (DFT) calculations. This work shows that the rational design of the number of layers in 2D MOF structures can tune the stability of these structures and opens a new avenue for the design of highly selective MOF photocatalysts.
Multi‐Wavelength Light‐Responsive Metal–Phenolic Network‐Based Microrobots for Reactive Species Scavenging
Authors: Guo Ziyi , Liu Tianyi , Gao Wanli , Iffelsberger Christian , Kong Biao , Pumera Martin
Published: January 2023

Light‐driven microrobots with different propulsion mechanisms have attracted great attention in microrobot synthesis and applications. However, current systems rely heavily on precious metals, using a complex synthesis process and limited working wavelength. It is therefore of great interest to fabricate microrobots that can be driven by multi‐wavelength irradiation and with simple components. Here, metal–phenolic network (MPN)‐based microrobots are synthesized using a sacrificial polystyrene bead template and an extra capping is added to regulate their symmetry. The hollow MPN microrobots with different layers of capping are capable of moving under both near‐infrared (NIR) irradiation and ultraviolet (UV) irradiation, without fuel. The velocity of the microrobots under irradiation is altered by the thickness of the asymmetric capping and their motion could be manipulated remotely by switching the NIR or UV irradiation on and off. With light‐driven mobility, the reactive oxygen and nitrogen species (RONS) scavenging activity of the microrobots is significantly increased. Therefore, this proposed microrobot system provides a synthesis strategy to develop asymmetric light‐navigated microrobots for future medical treatment with tunable structure, multi‐wavelength light‐responsive mobility, and great RONS scavenging capacity.
Compatible Solution‐Processed Interface Materials for Improved Efficiency of Polymer Solar Cells
Authors: Xu Zhuo , Madalaimuthu Jose Prince , Slowik Josef Bernd , Meitzner Rico , Anand Aman , Alam Shahidul , Corte Héctor , Stumpf Steffi , Schubert Ulrich S. , Hoppe Harald
Published: January 2023

The electron transport layer (ETL) in an organic solar cell is one of the main components that play a crucial role in the extraction of charges, improving efficiency, and increasing the lifetime of the solar cells. Herein, solution‐processed PBDTTT‐C‐T:PC71BM‐based organic solar cells are fabricated using conjugated PDINO molecules, sol‐gel derived under stoichiometric titanium oxide (TiOx), and a mixture of the same as an ETL. For PBDTTT‐C‐T:PC71BM‐based organic solar cells, a blend of organic‐inorganic ETLs demonstrates reduced bimolecular recombination and trap‐assisted recombination than a single ETL of either two materials. Furthermore, in both, fullerene and nonfullerene systems, the efficiency of the devices employing the blend ETL as compared to the single ETLs show some performance improvement. The strategy of integrating compatible organic and inorganic interface materials to improve device efficiency and lifetime simultaneously, and demonstrate the universality of different systems, has potential significance for the commercial development of organic solar cells.
Group 2 Innate Lymphoid Cells Protect Mice from Abdominal Aortic Aneurysm Formation via IL5 and Eosinophils
Authors: Zhang Yuanyuan , Liu Tianxiao , Deng Zhiyong , Fang Wenqian , Zhang Xian , Zhang Shuya , Wang Minjie , Luo Songyuan , Meng Zhaojie , Liu Jing , Sukhova Galina K. , Li Dazhu , McKenzie Andrew N. J. , Libby Peter , Shi Guo‐Ping , Guo Junli
Published: January 2023

Development of abdominal aortic aneurysms (AAA) enhances lesion group‐2 innate lymphoid cell (ILC2) accumulation and blood IL5. ILC2 deficiency in Rorafl/flIl7rCre/+ mice or induced ILC2 depletion in Icosfl‐DTR‐fl/+Cd4Cre/+ mice expedites AAA growth, increases lesion inflammation, but leads to systemic IL5 and eosinophil (EOS) deficiency. Mechanistic studies show that ILC2 protect mice from AAA formation via IL5 and EOS. IL5 or ILC2 from wild‐type (WT) mice, but not ILC2 from Il5−/− mice induces EOS differentiation in bone‐marrow cells from Rorafl/flIl7rCre/+ mice. IL5, IL13, and EOS or ILC2 from WT mice, but not ILC2 from Il5−/− and Il13−/− mice block SMC apoptosis and promote SMC proliferation. EOS but not ILC2 from WT or Il5−/− mice block endothelial cell (EC) adhesion molecule expression, angiogenesis, dendritic cell differentiation, and Ly6Chi monocyte polarization. Reconstitution of WT EOS and ILC2 but not Il5−/− ILC2 slows AAA growth in Rorafl/flIl7rCre/+ mice by increasing systemic EOS. Besides regulating SMC pathobiology, ILC2 play an indirect role in AAA protection via the IL5 and EOS mechanism.
Encapsulation of phenylacetic acid in block copolymer nanoparticles during polymerization induced self‐assembly
Authors: Li Guanrui , Barzycki Daniel C. , Ricarte Ralm G.
Published: January 2023

Polymerization induced self‐assembly (PISA) is an in situ method for producing block copolymer nanoparticles. Performing PISA in the presence of a pharmaceutical drug causes the nanoparticles to encapsulate the drug. While this approach is straightforward, the effects of drug loading and block copolymer composition remain unclear. Here, we investigate encapsulation of the drug phenylacetic acid (PA) in poly(glycerol monomethacrylate)‐block‐poly(2‐hydroxypropyl methacrylate) (PGMA‐PHPMA) nanoparticles during PISA. Nanoparticle morphology is characterized by electron microscopy and light scattering, while encapsulation efficiency () is quantified using nuclear magnetic resonance diffusometry. Increasing the PA loading shifts the nanoparticle morphology from spherical micelles cylindrical micelles vesicles. At a 32 mg/ml PA loading, maximizes at ~80%. Increasing the PHPMA degree of polymerization minimally impacts . The invariance of toward core block length suggests that PA binds to the nanoparticle corona, highlighting the importance of the hydrophilic block for drug encapsulation during PISA.
Clinical characteristics and outcome of 318 families with familial monoclonal gammopathy: A multicenter Intergroupe Francophone du Myélome study
Authors: Dumontet Charles , Demangel Delphine , Galia Perrine , Karlin Lionel , Roche Laurent , Fauvernier Mathieu , Golfier Camille , Laude Marie‐Charlotte , Leleu Xavier , Rodon Philippe , Roussel Murielle , Azaïs Isabelle , Doyen Chantal , Slama Borhane , Manier Salomon , Decaux Olivier , Pertesi Maroulio , Beaumont Marie , Caillot Denis , Boyle Eileen M. , Cliquennois Manuel , Cony‐Makhoul Pascale , Doncker Anne‐Violaine , Dorvaux Véronique , Petillon Marie Odile , Fontan Jean , Hivert Bénédicte , Leduc Isabelle , Leyronnas Cécile , Macro Margaret , Maigre Michel , Mariette Clara , Mineur Philippe , Rigaudeau Sophie , Royer Bruno , Vincent Laure , Mckay James , Perrial Emeline , Garderet Laurent
Published: January 2023

Familial forms of monoclonal gammopathy, defined as multiple myeloma (MM) or Monoclonal Gammopathy of Undetermined Significance (MGUS), are relatively infrequent and most series reported in the literature describe a limited number of families. MM rarely occurs in a familial context. MGUS is observed much more commonly, which can in some cases evolve toward full‐blown MM. Although recurrent cytogenetic abnormalities have been described in tumor cells of sporadic cases of MM, the pathogenesis of familial MM remains largely unexplained. In order to identify genetic factors predisposing to familial monoclonal gammopathy, the Intergroupe Francophone du Myélome identified 318 families with at least two confirmed cases of monoclonal gammopathy. There were 169 families with parent/child pairs and 164 families with cases in at least two siblings, compatible with an autosomal transmission. These familial cases were compared with sporadic cases who were matched for age at diagnosis, sex and immunoglobulin isotype, with 10 sporadic cases for each familial case. The gender distribution, age and immunoglobulin subtypes of familial cases were unremarkable in comparison to sporadic cases. With a median follow‐up of 7.4 years after diagnosis, the percentage of MGUS cases having evolved to MM was 3%. The median overall survival of the 148 familial MM cases was longer than that of matched sporadic cases, with projected values of 7.6 and 16.1 years in patients older and younger than 65 years, respectively. These data suggest that familial cases of monoclonal gammopathy are similar to sporadic cases in terms of clinical presentation and carry a better prognosis.
The Composite Immune Risk Score predicts overall survival after allogeneic hematopoietic stem cell transplantation: A retrospective analysis of 1838 cases
Authors: Cao Yigeng , Gong Xiaowen , Feng Yahui , Wang Mingyang , Hu Yu , Liu Huilan , Liu Xueou , Qi Saibing , Ji Yanping , Liu Fang , Zhu Huaiping , Guo Wenwen , Shen Qiujin , Zhang Rongli , Zhao Ningning , Zhai Weihua , Song Xiaoqiang , Chen Xin , Geng Liangquan , Chen Xia , Zheng Xuetong , Ma Qiaoling , Tang Baolin , Wei Jialin , Huang Yong , Ren Yuanyuan , Song Kaidi , Yang Donglin , Pang Aiming , Yao Wen , He Yi , Shang Yue , Wan Xiang , Zhang Wei , Zhang Song , Sun Guangyu , Feng Sizhou , Zhu Xiaofan , Han Mingzhe , Song Zhen , Guo Ye , Sun Zimin , Jiang Erlie , Chen Junren
Published: January 2023

There has been little consensus on how to quantitatively assess immune reconstitution after hematopoietic stem cell transplantation (HSCT) as part of the standard of care. We retrospectively analyzed 11 150 post‐transplant immune profiles of 1945 patients who underwent HSCT between 2012 and 2020. 1838 (94.5%) of the cases were allogeneic HSCT. Using the training set of patients (n = 729), we identified a composite immune signature (integrating neutrophil, total lymphocyte, natural killer, total T, CD4+ T, and B cell counts in the peripheral blood) during days 91–180 after allogeneic HSCT that was predictive of early mortality and moreover simplified it into a formula for a Composite Immune Risk Score. When we verified the Composite Immune Risk Score in the validation (n = 284) and test (n = 391) sets of patients, a high score value was found to be associated with hazard ratios (HR) of 3.64 (95% C.I. 1.55–8.51; p = .0014) and 2.44 (95% C.I., 1.22–4.87; p = .0087), respectively, for early mortality. In multivariate analysis, a high Composite Immune Risk Score during days 91–180 remained an independent risk factor for early mortality after allogeneic HSCT (HR, 1.80; 95% C.I., 1.28–2.55; p = .00085). In conclusion, the Composite Immune Risk Score is easy to compute and could identify the high‐risk patients of allogeneic HSCT who require targeted effort for prevention and control of infection.
Waldenström macroglobulinemia: 2023 update on diagnosis, risk stratification, and management
Authors: Gertz Morie A.
Published: January 2023

Disease Overview

Waldenström macroglobulinemia (WM) is a lymphoplasmacytic lymphoma with immunoglobulin M (IgM) monoclonal protein. Clinical features include anemia, thrombocytopenia, hepatosplenomegaly, lymphadenopathy, and rarely hyperviscosity.

Diagnosis

Presence of IgM monoclonal protein associated with ≥10% clonal lymphoplasmacytic cells in bone marrow confirms the diagnosis. The L265P mutation in MYD88 is detectable in more than 90% of patients and is found in most IgM MGUS patients. MYD88 is not required for the diagnosis.

Risk Stratification

Age, hemoglobin level, platelet count, β2 microglobulin, LDH, and monoclonal IgM concentrations are characteristics that are predictive of outcomes.

Risk‐Adapted Therapy

Not all patients who fulfill WM criteria require therapy; these patients can be observed until symptoms develop. Rituximab‐monotherapy is inferior to regimens that combine it with bendamustine, an alkylating agent, a proteosome inhibitor, or a BTK inhibitor. The preferred Mayo Clinic induction is either rituximab and bendamustine (without rituximab maintenance) or zanubrutinib.

Management of Refractory Disease

Bortezomib, cyclophosphamide, fludarabine, thalidomide, everolimus, Bruton Tyrosine Kinase inhibitors, carfilzomib, lenalidomide, bendamustine, and venetoclax have all been shown to have activity in relapsed WM. Given WM's natural history, the reduction of therapy toxicity is an important part of treatment selection.