bluuebunny/crossref_metadata_2025 huggingface dataset:
Practical ship noise level measurements in shallow water
Authors: Abrahamsen Kai A.
Published: November 2019

Ship noise radiation has been recognized as an important environmental factor which attracts increasing attention. It is important to be able to measure the noise radiation in order to control ship noise and to evaluate consequences of ship generated noise. Operation of ships is associated with significant costs. Large cruise vessels may have operational costs in the range 10–20 000.-$ per hour. Smaller merchant vessels are less expensive, but the operational costs are still an important factor. Hence, it is important to be able to perform underwater noise measurements fast at or near the sailing area of the vessel using mobile equipment. Underwater noise measurements can be rather complex if all theoretical influences are to be controlled, but may be simplified if considered in a practical way and still yield acceptable accuracy. This talk will describe practical ways to perform underwater noise measurements, discuss factors leading to variability in the measurements and describe how to limit the variability as much as possible while still keeping the measurements within a simple practical frame.
Merchant vessel source level estimation from low-frequency vector sensor systems
Authors: Smith Kevin B. , Leary Paul , Deal Thomas J.
Published: November 2019

Low-frequency acoustic vector sensor systems deployed in propagation favorable locations have the potential to not only provide accurate tracking of distant merchant vessels but also, with a combination of AIS data and propagation modeling, produce good estimates of ship source levels. In this work, data from two similar low-frequency acoustic vector sensor systems will be examined using this approach. One system collected data approximately 3 km off the coast of Big Sur, California at the edge of the shelf break, while the other system collected data from a depth of about 900 m near the mouth of the Monterey Bay Canyon. Directional and temporal variations in the ambient noise field will also be evaluated, and causes will be considered including flow noise due to currents, surface (wind) noise, distant shipping, and marine mammals. Bearing estimation results for shipping will be compared with AIS tracks recorded during the periods of deployment. Local sound speed measurements and bathymetry in the vicinity of the deployment area will be used as inputs to a two-dimensional propagation model that properly invokes reciprocity of the acoustic vector field. The results from each system will be compared with the goal of reducing model uncertainty.
Vector acoustic study of ship noise during the 2017 Sediment Characterization Experiment off New England
Authors: Dahl Peter H. , Dall'Osto David R.
Published: November 2019

The Intensity Vector Autonomous Recorder (IVAR) is a bottom deployed system measuring particle velocity and pressure. Results using IVAR in the Sediment Characterization Experiment (SBCEX) conducted off New England (spring 2017), involving active sources have been presented [P. H. Dahl and D. R. Dall’Osto, IEEE J. Ocean. Eng. (2019)]. Here, passive ship noise is studied from a 200-m length cargo vessel that is tracked over a 10 km course a 15 knots for which the closest point of approach (CPA) to the IVAR deployment location (1.25 m above the seafloor) was 500 m, as confirmed by Automatic Identification System (AIS) data. The time-frequency interference pattern of the noise as the vessel closes and opens in range is studied by way of vector acoustic field indicators. These are non-dimensional ratios of second-order quantities, e.g., kinetic energy over potential energy, which preserve magnitude over the track. Inferences on the seabed made from study of the field indicators are compared with geoacoustic models emerging from studies related to SBCEX. The aspect-dependent source level of the vessel is also estimated, with method tested on a known, omni-directional source towed past IVAR from the research vessel R/V Endeavor. [Study supported by Office of Naval Research.]
Ship source level estimation in an uncertain environment via trans-dimensional Bayesian inversion
Authors: Tollefsen Dag , Knobles David P. , Dosso Stan E. , Hodgkiss William S.
Published: November 2019

This paper considers the joint estimation of ship source spectral levels and environment parameters of a layered seabed via a trans-dimensional Bayesian matched-field inversion approach, with applications to shallow-water data collected with acoustic arrays in the 2017 Seabed Characterization Experiment conducted on the New England Shelf. The approach samples probabilistically over possible model parameterizations (number of seabed layers), and provides uncertainty estimates of ship source levels that include uncertainty due to the environment and source depth/range. Approaches to modeling of a distributed source (i.e., as multiple point sources) in the inversions will also be considered. The approach is applied to low-frequency tonal (propeller and machinery) noise in the 10–300 Hz frequency band due to large container ships passing near the arrays.
A comparison of quiet ship certifications with the Enhancing Cetacean Habitat Observation (ECHO) ship noise database
Authors: Hannay David E. , Frouin-Mouy Heloise , Wladichuk Jennifer L. , Pace Federica , MacGillivray Alexander O.
Published: November 2019

Measurements from the large ship noise database acquired by the Vancouver Fraser Port Authority’s Enhancing Cetacean Habitat Observation (ECHO) program were used to assess the conservativeness of five vessel noise certification societies. A multi-variate linear regression analysis of the database was used to scale ECHO measurements to a common reference vessel type for each of 6 categories: tug, tanker, bulker, container ship, vehicle carrier, cruise ship. The purpose of scaling the ECHO measurements was to create a modified dataset to compare with existing vessel noise certification society noise thresholds. The conservativeness of the certification society thresholds was found to vary with vessel category. The general findings are that the society limits are conservative for faster categories (e.g., container ship) but not for slower vessels such as tankers, and certification systems using monopole source level (MSL) had better matches with measurement data than the approaches using radiated noise level (RNL). None of the certification societies accounts for differences of vessels within a vessel category. Therefore, small ships are currently evaluated against the same threshold criteria as large ships. The scaling system developed here using the ECHO dataset could be used to scale measurements (or thresholds) to account for different vessel sizes and operating conditions. This research was funded by Transport Canada.
Small-boat source level estimates in a fjord environment
Authors: Smistad Ragnhild , Buen Helge , Tollefsen Dag
Published: November 2019

Small vessels contribute to noise in the marine environment and it is of interest to measure radiated noise levels of such. This paper presents measurements of radiated noise from small leisure boats (lengths 16 to 23 ft) conducted at a shallow water site in a fjord environment. The measurements used a bottom-deployed tripod with three hydrophones, and a laser instrument for boat range and speed estimation. Data were processed for source levels in one-third octave frequency bands from 0.1 to 1.6 kHz and using the ANSI/ASA standard for distance normalization. For boats moving at speeds 4 to 6 km, source levels varied by up to 20 dB between boat types. Estimated broadband source levels were 8 to 22 dB lower than for merchant vessels previously measured in the same environment.
Analysis of systematic source level measurements of small vessels
Authors: Wladichuk Jennifer L. , Hannay David E. , MacGillivray Alexander , Li Zizheng , Thornton Sheila
Published: November 2019

Improving our knowledge of how sound impacts marine mammals is particularly important where the spatial distributions of vessels and marine mammals overlap, as exemplified by the critical habitat for the endangered Southern Resident Killer Whale (SRKW). In this study, two acoustic recorders were deployed in transboundary Haro Strait (British Columbia, Canada and Washington State, USA) from July to October 2017 to measure sound levels produced by whale-watching vessels and other small boats. During this period, 20 different volunteer vessels were assessed operating at a range of speeds—nominally 5 knots, 9 knots, and cruising speed. The measurement protocol was designed based on ANSI S12.64-2009. For all vessels, we observed positive correlations between source levels and speed; however, the speed trends (slope of curves) were not as strong as those of large commercial vessels. Mean source levels were computed for each vessel type in the broadband frequency range (0.05–64 kHz), the SRKW communication band (0.5–15 kHz), and the SRKW echolocation band (15–64 kHz) at each speed. Here we discuss how source levels were affected by vessel speed, hull shape and propeller type, as well as the positive and negative aspects of the protocol design.
Formalizing noise field beam correlation techniques for analyzing deep layers
Authors: Gebbie John , Siderius Martin
Published: November 2019

This work takes an information theoretic approach to understanding and characterizing beam correlations within the ambient noise field and discusses the implications for passive seabed geoacoustic estimation, particularly as it applies to deep layers. The passive fathometer [J. Acoust. Soc. Am. 120(3), 1315–1323 (2006)] and head wave correlation analysis [J. Acoust. Soc. Am. 140(1), EL62–EL66] are examples of techniques that use beam correlations and have generated interest given their ability to expose information about geo-acoustic properties as well as the layering structure of the bottom. However, the conditions under which these techniques can operate, what information is actually available, and which multilayer properties can be independently estimated, are open questions. Formal answers come in the form of the Cramér-Rao lower bounds (CRLB), but this requires an exact definition of the probability function for a cross-beamformer output defined in the space of the multilayered bottom properties. Often prior information about a site is available, and this can readily be incorporated to yield the Bayesian CRLB, which allows this approach to be used for experimental design. The theoretical framework for the Bayesian CRLB will be presented along with simulation and measured data examples.
Observations of compressional, shear and interface waves in the New England Mudpatch
Authors: Miller James H. , Potty Gopu R. , Lin Ying-Tsong , Bonnel Julien , Newhall Arthur , Yang Jie , Chaytor Jason D.
Published: November 2019

In March 2017, instruments including a tetrahedral hydrophone array and vertically gimbaled geophones were deployed during the Seabed Characterization Experiment in the New England Mudpatch south of Martha’s Vineyard. The water depth at the location was about 70 m and a 6-m-thick layer of fine-grained sediments overlays sand layers. The relative positions of the geophones were localized using a time-difference-of-arrival (TDOA) technique applied to signals from Mk-64 SUS charges at various aspects and ranges from 5 to 25 km. In addition, noise from a research vessel provided information on relative depths of the geophones. The geophones were found to have sunk into the soft mud, and this provided a unique opportunity to sense shear waves in the mud and Stoneley waves on the mud-sand interface. In addition, post-Airy Phase arrivals are thought to be shear waves generated at the mud-sand boundary. Interface waves were generated by the interface Wave Sediment Profiler (iWaSP), an instrument with bender beams oriented to shake the seabed. Estimates using iWaSP of shear speed in the mud and sand layers were consistent with inversions using modal dispersion measured on the tetrahedral hydrophone array reported by Potty and Miller (2019). [Work supported by the Office of Naval Research.]
Diffraction and scattering at the seafloor
Authors: Stephen Ralph A.
Published: November 2019

In bottom-interacting ocean acoustics discrete, deterministic arrivals with significant energy are returned from the seafloor at angles that are not predicted by Snell’s law. This observation has led to some confusion between the terms “diffraction” and “scattering” as used in ocean acoustics. The common dictionary definitions of diffraction, as the process by which a beam is spread out or bent after passing the edge of an obstacle, and of scattering, as deflecting waves in a more or less random fashion, do not describe the observed seafloor interaction where a pulse of energy is returned deterministically, not randomly, from the seafloor in a non-Snell’s law direction. In ocean acoustics and marine seismology, it is rare to consider “bending diffraction” but it is quite common to see “scattering diffraction,” for example, as diffraction hyperbolas on bottom profiling and seismic records. For impulsive sources, in addition to specular reflections and random scattering from the seafloor, a significant aspect of bottom-interacting acoustics in deep water is diffraction of energy from discrete seafloor locations along repeatable paths in three-dimensions. [Work supported by ONR.]
Models mimicking characteristics of the urinary system and stones relevant to lithotripsy
Authors: Maxwell Adam D. , Hunter Christopher , Chen Tony T. , Wang Yak-Nam , Lynch Elizabeth , Dunmire Barbrina , Bailey Michael R. , Williams James C. , Kreider Wayne
Published: November 2019

Both new and established modes of noninvasive lithotripsy are often tested in an in vitro apparatus to evaluate the efficacy of different technologies and exposures to fragment urinary stones. A significant challenge for these experiments is to accurately replicate the physical properties of a stone and the surrounding urinary tract. Such a task requires appropriate models for the stone, the fluid, and the tissue, all of which can contribute to stone fragmentation. This presentation will describe research into new models to more accurately replicate the fracture of natural human stones, including artificial models and natural stones from other mammalian species. Experiments show several factors such as fluid gas concentration, tissue phantom properties, and fluid confinement and also affect cavitation behavior and lithotripsy effectiveness. Experiments measuring such cavitation activity in vivo in a porcine model and correlation with in vitro observations will be presented. Altogether, these studies suggest that lithotripsy experiments are dependent on these characteristics and require careful choice of models to mimic in vivo scenarios. [Work supported by NIDDK K01 DK104854 and P01 DK043881.]
Simulation of acoustic backscattered field from a medium with randomly distributed fibers
Authors: Kari Mohammadreza , Feltovich Helen , Hall Timothy J.
Published: November 2019

Common assumptions in quantitative ultrasound include that the medium is homogeneous and isotropic and has diffuse scattering conditions. In some soft tissues, due to the presence of fiber-like structures, the medium is anisotropic and has a periodic scattering condition. Skeletal muscle is an example in which the fibers are highly aligned, a coherent scattering condition appears. Using the closed form solution of acoustic backscattered field from immersed finite cylindrical targets, this work presents a simulation study of a medium containing randomly distributed fibers. The effective scatterer diameter and average backscatter coefficient of the medium are calculated and compared with the change in fiber orientation. The effects of other parameters such as number of fibers and their lengths are also analyzed. In addition, different distributions of parameters such as normal or uniform distributions are considered, and their effects on the backscattered field are studied.
Experimental investigation of acoustic backscattered field from a medium with random and aligned fibers
Authors: Kari Mohammadreza , Feltovich Helen , Hall Timothy J.
Published: November 2019

Some soft tissues, such as skeletal muscles, have fiber-like structures that make them anisotropic. Acoustic backscattering from such tissues or media has been of interest to many scientists in biomedical fields because it complicates interpretation of imaging data. Backscatter coefficient measurements show diagnostic promise for this purpose both in vitro and in vivo. Many parameters, e.g., effective scatterer diameter or average scattering strength, can be estimated with acoustic backscatter measurements. In the present work, we experimentally study the backscatter coefficient of a medium with aligned or random fibers and estimate the effect of fiber orientation upon the backscattered field and the estimated scatterer diameter. Using an experimental approach, we explore the relationship between the backscatter coefficient of a medium with multiple fibers and with a single fiber. In addition, we investigate the effect of the spatial Fourier transform of the fiber distribution in the medium with its frequency dependence of backscatter coefficients. The experimental results show that backscatter coefficients of a medium with random fibers can be modeled by the product of number density of fibers, backscatter coefficients of the same single fiber, and the spatial Fourier transform of the fiber distribution.
Aberration correction using nonlinear backscattered signals from the focus of an ultrasound beam
Authors: Bawiec Christopher R. , Khokhlova Vera A. , Sapozhnikov Oleg A. , O'Donnell Matthew , Hunter Christopher , Ghanem Mohamed A. , Peek Alex T. , Khokhlova Tatiana D.
Published: November 2019

High intensity focused ultrasound (HIFU) therapies are often affected by aberrations, which can severely limit treatments. For multi-element arrays, applying phase corrections for each element could mitigate these effects. Here, an aberration correction method based on cross-correlation of nonlinear HIFU waves, backscattered from the focus is proposed and tested. A spherically focused 1.5 MHz 256-element HIFU array powered by Verasonics system was used for both emitting and receiving backscattered ultrasound waves. A short (3-cycle) high-amplitude pulse was transmitted through an aberrating layer into an ex vivo clotted bovine blood sample. The backscattered signal was recorded by individual array elements and high-pass filtered at 4 MHz. The layer introduced different acoustic path lengths for individual elements leading to a decrease in the peak-positive pressure of ~70%. The time delay required for each element to restore the nonlinear waveform at the focus was calculated based on the cross-correlation between the backscattered filtered signals. The results were confirmed by replacing the sample with a hydrophone. Using the corrected time delays, peak-positive focal pressure increased over 75% from uncorrected aberrated levels. These results demonstrate that the proposed focal “nonlinear beacon” can be used for phase correction feedback in HIFU treatments of soft tissue. [Work supported by NIH R01GM122859, R01EB007643, and RSF19-12-00148.]
Ultrasound elastography monitoring reveals a decline in shear wave attenuation and clot viscosity after recombinant tissue plasminogen activator treatment of blood clots
Authors: Bosio Guillaume , Bhatt Manish , Cloutier Guy
Published: November 2019

Deep vein thrombosis is one of the leading causes of disability and serious illness and can become fatal. The lytic recombinant tissue plasminogen activator (rt-PA) is the main drug used for clot lysis and rapid normalization of venous blood flow. Less than 40% of patients who receive rt-PA treatment have improved blood flow. In this study, we quantitatively monitor the rt-PA treatment in in-vitro blood clots with ultrasound elastography. An acoustic radiation force imaging sequence was implemented on a research ultrasound system to remotely generate shear waves inside the blood clot samples. Porcine blood samples from two different pigs were bought from a local slaughterhouse. Clots of varying viscoelasticity were prepared by allowing different coagulation time between 30 min to 3 days in borosilicate glass pipettes. The clots were then embedded in gelatin-agar phantoms to perform ultrasound measurements. Another batch of clots from the same blood samples was treated with rt-PA drug for 30 min, and ultrasound measurements were performed after treatment. In 11 samples, variations in SW speed before and after rt-PA treatment were not found to be statistically significant (>0.05). However, SW attenuation and clot viscosity declined significantly after rt-PA treatment by 33.49% ± 31.07% (<0.05) and 33.33% ± 35.72% (<0.05). The results indicate that SW attenuation and viscosity can be used to monitor DVT treatment, and clot viscosity may emerge as an important biomarker for clot staging.
Novel bilayer aberration-inducing gel phantom for high-intensity focused ultrasound applications
Authors: Peek Alex T. , Khokhlova Tatiana D. , Rosnitskiy Pavel B. , Yuldashev Petr V. , Bawiec Christopher R. , Kreider Wayne , Hunter Christopher , Sapozhnikov Oleg , Khokhlova Vera A.
Published: November 2019

Aberrations induced by soft tissue inhomogeneities often complicate HIFU therapies. In this work, a bilayer phantom made from polyvinyl alcohol hydrogel (PVA) and ballistic gelatin (BG) was built to mimic alternating layers of water-based and lipid tissues characteristic for a body wall and reproducibly distort HIFU fields. The density (1.04 g/ml PVA, 0.86 g/ml BG), sound speed (1520 m/s PVA, 1450 m/s BG), attenuation coefficient (0.016 dB/cm MHz PVA, 0.052 dB/cm MHz BG) of gel materials, and nonlinearity coefficient close to that of water were measured using homogeneous gel layers of 4 cm thickness. A 3-D-printed mold was fabricated to generate the random interface between the gel layers. The interface pattern was designed using a 2-D Fourier spectrum approach replicating different spatial scales of tissue inhomogeneities. Distortion of the field of a 256-element 1.5 MHz HIFU array by the phantom was characterized through hydrophone measurements for both linear and nonlinear beam focusing. Both spatial shift (up to 2.3 mm axially and 0.35 mm transversely) and widening of the focus were observed, as well as dramatic reduction in focal pressures caused by aberrations (up to fourfold decrease in the peak positive pressure for a focal waveform with developed shock). [Work supported by NIH R01EB007643, R01GM122859, and R01EB025187.]
Direct error in constitutive equation formulation for inverse problems in time harmonic viscoelasticity
Authors: Barbone Paul E. , Babaniyi Olalekan A.
Published: November 2019

We present a variational formulation for inverse viscoelasticity problems based on minimizing the error in a constitutive equation. This is formulated as a quadratic minimization problem with linear constraints and, hence, is amenable to a direct solution with a single solve. Here, we extend our prior work with scalar waves to inverse viscoelasticity, intended for application to shear wave fields excited by acoustic radiation force pulses. We demonstrate that the problem is ill-posed with a single wave field but is stable with two measured wave-fields. We compare two approaches using two input wave-fields: first, we consider using two wave fields excited by two different push pulse configurations. Second, we consider using a single push pulse but combining information across frequencies.
Flow phantom for contrast enhanced ultrasound research, device validation, and clinical training
Authors: Matula Thomas , Kucewicz John , Dunmire Barbrina
Published: November 2019

Phantoms are an important part of ultrasound research, instrument development, and clinical training. There are, however, no standardized phantoms for contrast enhanced ultrasound. Phantoms typically include either tubes to mimic flow in larger vessels or dialysis tubing to mimic perfusion in the capillary bed. These approaches fail to mimic the full range of flow regimes and tissue scattering observed in the body during imaging. To address some of these limitations, we designed a phantom that integrates flow in both the macro- and microcirculation with physiological tissue backscatter, attenuation, and sound speed and that can be customized to simultaneously mimic flow in normal and malignant tissues. A variety of sponges and foams were considered. Acceptable materials were fit in a custom-built flow chamber and imaged with a commercially available ultrasound system. A polyvinyl alcohol (PVA) sponge was deemed to be a suitable phantom material. PVA has a sound speed of 1490 m/s and attenuation coefficient of 0.6 dB/cm/MHz. After introducing a contrast agent into the flow system, the agent could be visualized rapidly entering the flow inlets, perfusing slowly through the sponge, and rapidly exiting through the flow outlets. [Funded by Philips Ultrasound and the Life Sciences Discovery Fund No. 3292512.]
Using graphics programming methods in PC SWAT
Authors: Woods Denton
Published: November 2019

The Panama City Shallow Water Acoustic Toolset (PC SWAT), developed at the Naval Surface Warfare Center Panama City Division (NSWC PCD), simulates sonar performance for a wide variety of underwater environments. Recent technical enhancements in the simulation package include the addition of triangular target scattering using the Kirchhoff approximation, enabling the use of arbitrary 3-D targets. Technical inspiration and techniques borrowed from the graphics programming community that have been adapted to improve performance predictions and fidelity of the sonar simulator package will be presented.
Numerical method for prediction of duct break out sound power
Authors: Williams Paul T. , Kirby Ray , Hill James
Published: November 2019

The acoustic design of duct systems requires consideration of both the noise propagating within a duct and also of the noise transmitted out through the duct walls into the environment. Control of this breakout noise can form a significant part of a noise control solution, and so understanding this phenomenon can lead to reduced material use. The breakout noise is investigated here using coupled structural-acoustic finite element models. Propagation along a waveguide with constant cross section is represented using a modal expansion of the acoustic pressure in the fluid and displacement in the duct walls. The free-field external environment requires an outer boundary condition, and for this purpose, a perfectly matched layer is applied at some distance from the elastic walls. The finite length of the waveguide is then enforced by coupling the fields to separate infinite length inlet and outlet ducts by the mode matching method. Transmitted power from the finite length duct is investigated when a noise source is placed in the inlet.
AI methods for duct acoustics
Authors: Sack Stefan , Yang Cheng , Åbom Mats
Published: November 2019

Acoustic mode decomposition is commonly used to separate pressure wave components in flow ducts, and established methods relay on mathematical descriptions of the wave motion. In this work, a new approach to mode decomposition is presented which uses artificial intelligence (AI) to separate the acoustic mode content. A neural network is trained with data gained from a small set of numeric solutions of the Linearized Navier-Stokes equation in the frequency domain in a straight duct. The network is tested on relevant experimental data. Good agreement with the analytical method is demonstrated in two applications with different flow conditions. We conclude that using AI for mode decomposition is a promising alternative to the standard method as it is applicable to a much broader set of aero-acoustic problems.
Helmholtz-Kirchhoff integral formula for predicting the acoustic pressure from a radiator including irregular surface
Authors: Been Kyounghun , Lee Junsu , Moon Wonkyu
Published: November 2019

The Helmholtz-Kirchhoff integral (HKI) for the radiation problem from a finite source with a vibrating surface is a method of calculating the acoustic pressure at any position in the three-dimensional space using the velocity conditions of the radiating surface. Previous studies predicted the acoustic pressure from the radiator based on the HKI. However, the acoustic pressure should be evaluated first on the radiation surface in order to calculate the acoustic pressure in the space. Nonetheless, it is difficult to evaluate the acoustic pressure on the radiation surface accurately if there are non-smooth points. Because the exact HKI is not easily found to be applicable for the evaluation, in this study, we investigated the HKI from the beginning. Through the process of deriving the formula, we proposed the form of the HKI that can be used for calculating the acoustic pressure at both smooth and non-smooth points of the radiation surface. The proposed formula is also proved mathematically. As a result, the acoustic pressures calculated by the proposed formula are compared to those using a FEM. The results yield that the overall relative errors are less than 2% even on the radiator surface including vertices. [Work supported by Samsung Display Corporation.]
Ultrasonic wave transport in resonant emulsions made of slow or fast droplets
Authors: TALLON Benoit , Brunet Thomas , Page John H.
Published: November 2019

The key transport parameters of acoustic waves travelling in disordered media are studied through ultrasonic experiments on monodisperse resonant emulsions. Through accurate measurements of both ballistic and diffusive transport over a wide range of frequencies, we show that the group velocity of the ballistic component may differ significantly from the energy velocity of the diffusive waves, in particular in the vicinity of scattering resonances. Moreover, we demonstrate the crucial role played by the refractive acoustic index of the droplets relative to the surrounding media by studying emulsions made of “slow” fluorinated oil droplets or “fast” liquid metallic droplets dispersed in a water-based gel. Our observations are successfully explained by theories based on independent scattering approximations relevant for these diluted media. Effects of droplet resonances in the diffusive regime are also discussed giving a complete study of the energy velocity of scalar waves in strongly scattering media. B. Tallon, T. Brunet, and J.H. Page, Phys. Rev. Lett. 119, 164301 (2017).
Focusing of rarefaction wave and dynamics of cavitation zone state behind its front in two-phase cylindrical liquid layer
Authors: Kedrinskiy Valeriy , Bolshakova - Zhuravleva Ekaterina
Published: November 2019

The evolution of the cavitation zone behind the front of a converging cylindrical rarefaction wave (RW) in a layer of two-phase distilled water is investigated numerically within the IKvanW mathematical model. The process is initiated by the generation of a shock wave (SW) exponential profile by the coaxial piston in the vicinity of the axis symmetry (R = 0 mm) in the wide range of amplitudes (Umax = 40–200 m/s) and time constants of exponent (10–40 μs). SW propagates along the radius of layer and reflects from a free surface (R = 60 or 100 mm) forming RW. The analysis of influence of SW parameters (at given exponent 10 μs for all amplitudes Umax) on the state of the cavitation zone has shown that the cavitation process is smoothly intensified for each value Umax in the distance ranging from 100–40 mm. Then, it drastically increases approaching the axis (interval 40–20 mm) and reaches 3500 units of the concentration (for Umax = 200 m/s). The total concentration becomes more than 6%. It is of interest to note that a significant effect produced by the changes in the initial parameters of state and in exponents (at Umax = 100 m/s): (1)—at R0 = 1.5 μm, k0 = 10-5, the calculation for exponent 40 μs practically coincides with the results for 30 μs. Thus, the latter can be considered as a limit value for the accepted parameters of two-phase medium state (total concentration reaches 2%) and (2)—at R0 = 7 μm, k0 = 10-3, the concentration distributions increase separately for each exponent and total concentration reaches value close to 16%.
Effect of a mass flux at bubble-liquid interface on propagation properties of weakly nonlinear waves
Authors: Fujimoto Aya , Kamei Takafumi , Ayukai Takahiro , Kanagawa Tetsuya
Published: November 2019

Toward the establishment and realization of medical applications accompanied with a phase change such as a drug delivery system, a formulation of the effect of mass transfer (i.e., mass flux) at the bubble-liquid interface on a ultrasound propagation process has been desired. Since a large amplitude ultrasound is utilized in such an application, the consideration of both the mass flux and the wave nonlinearity is essential. Although Fuster and Montel [J. Fluid Mech.(2015)] investigated linear wave propagation, nonlinear analysis has not been performed. In this paper, we theoretically clarify the effect of mass flux at the bubble-liquid interface on weakly nonlinear (i.e., finite but small amplitude) propagation of pressure waves in bubbly liquids. The effect of total evaporation or condensation as a mass flux across the bubble interface is taken into account as a simple classical model. Although various types of dissipation are installed, the effect of viscosity of gas inside the bubble is neglected. The set of basic equations for bubbly flows is composed of the conservation laws of mass, momentum, and energy, equation of motion for radial oscillations of bubble wall, equations of state, and so on. From the method of multiple scales, some nonlinear wave equations (e.g., KdV-Burgers equation) are derived. We then discuss the effects of mass flux on the propagation processes of nonlinear waves.
Derivation of an amplitude equation for pressure wave propagation in polydisperse bubbly liquids
Authors: Ishitsuka Reona , Kanagawa Tetsuya
Published: November 2019

A weakly nonlinear propagation of plane progressive pressure waves in an initially quiescent water uniformly containing small gas bubbles is theoretically investigated. In the present study, the bubbles do not coalesce, break up, appear, and disappear. The bubbles are spherical, and these oscillations are spherically symmetric. In addition, the viscosity of gas inside the bubbles and the thermal conductivities of the both phases are neglected. Although abovementioned assumptions were used in our previous studies [e.g., Kanagawa et al., J. Fluid Sci. Technol.(2010); Kanagawa, J. Acoust. Soc. Am. (2015)] and classical studies [e.g., van Wijngaarden, J. Fluid Mech. (1968)], we here incorporate polydispersity of bubbly liquids. From the method of multiple scales, an amplitude (or a nonlinear wave) equation describing a long-range propagation of waves in bubbly liquids is derived from the basic equations in a two-fluid model. By comparing the present result with the previous results assuming monodispersity, we qualitatively and quantitatively discuss an effect of polydispersity on the wave propagation process in bubbly liquids.
Overview of the fixed base correction method for modal testing on dynamic boundary conditions
Authors: Kerrian Peter , Napolitano Kevin
Published: November 2019

Modal tests are important steps in the validation of structural dynamic finite element models of test articles. Often, inadequate boundary conditions require more effort to be spent correlating the boundary condition or support structure rather than the test article. Recently, boundary condition correction methods, such as the fixed base correction method, have been developed to extract fixed based mode shapes for test articles on dynamic test fixtures. This paper presents an overview of the fixed base correction method and provides examples of the implementation to academic and representative test articles.
A comparative analysis of fitness flooring buildups designed for heavy weight impacts
Authors: Scarlett Jessica
Published: November 2019

A comparitve analysis of fitness flooring builups designed for heavy weight impacts. Multiple combinations of polyurethane foam and rubber topping layers were laboratory tested for sound and vibration performance. Variables included polyurethane density and thickness and rubber topping thickness, mass of weights dropped, and height of weights dropped. The review of data aims to identify ideal buildups for specific weight impacts and drop heights.
Activated leukocyte cell adhesion molecule regulates B lymphocyte migration across central nervous system barriers
Authors: Michel Laure , Grasmuck Camille , Charabati Marc , Lécuyer Marc-André , Zandee Stephanie , Dhaeze Tessa , Alvarez Jorge I. , Li Rui , Larouche Sandra , Bourbonnière Lyne , Moumdjian Robert , Bouthillier Alain , Lahav Boaz , Duquette Pierre , Bar-Or Amit , Gommerman Jennifer L. , Peelen Evelyn , Prat Alexandre
Published: November 2019

Activated leukocyte cell adhesion molecule mediates B lymphocyte migration across central nervous system barriers.
Prospective clinical testing and experimental validation of the Pediatric Sepsis Biomarker Risk Model
Authors: Wong Hector R. , Caldwell J. Timothy , Cvijanovich Natalie Z. , Weiss Scott L. , Fitzgerald Julie C. , Bigham Michael T. , Jain Parag N. , Schwarz Adam , Lutfi Riad , Nowak Jeffrey , Allen Geoffrey L. , Thomas Neal J. , Grunwell Jocelyn R. , Baines Torrey , Quasney Michael , Haileselassie Bereketeab , Lindsell Christopher J.
Published: November 2019

Prognostic biomarkers for pediatric septic shock are conserved in a murine model of sepsis and accelerate testing of precision medicine strategies.
Comparison of Two Typing Methods for Characterization of Azole Resistance in Aspergillus fumigatus from Potting Soil Samples in a Chinese Hospital
Authors: Fan Hong , Chen Yong , Duan Liping , Zhao Jingya , Qin Chunping , Li Haifeng , Sun Jinke , Han Li
Published: November 2019

To understand the characterizations of azole resistance in
Aspergillus fumigatus
from potting soil samples in the hospital, a total of 58 samples were collected. Among 106
A. fumigatus
samples obtained, 5 isolates from 4 soil samples located in the gerontology department were identified as azole-resistant
A. fumigatus
(ARAF). Four ARAF isolates harbored the TR
34
/L98H allele, and the other one had no mutation in the
cyp51A
gene.
Precision Medicine and Mysteries in Clinical Microbiology: Rationalizing Epidemiology, Genotype, and Phenotype To Guide Therapeutics
Authors: Perez Federico , Bonomo Robert A.
Published: November 2019

Whole-genome sequencing (WGS) using MinION was used to characterize high-risk clones of
Escherichia coli
and
Klebsiella pneumoniae
harboring
bla
NDM-5
,
bla
OXA-181
, and
bla
CTX-M-15
, as well as
Pseudomonas aeruginosa
harboring
bla
NDM
, in a patient who received health care in India. Synergy testing demonstrated the activity of aztreonam and ceftazime-avibactam in combination.
Antigenic Variation in
Neisseria gonorrhoeae
Occurs Independently of RecQ-Mediated Unwinding of the
pilE
G Quadruplex
Authors: Voter Andrew F. , Callaghan Melanie M. , Tippana Ramreddy , Myong Sua , Dillard Joseph P. , Keck James L.
Published: November 2019

The pathogenic bacteria
Neisseria gonorrhoeae
avoids clearance by the immune system through antigenic variation (AV), the process by which immunogenic surface features of the bacteria are exchanged for novel variants. RecQ helicase is critical in AV and its role has been proposed to stem from its ability to unwind a DNA secondary structure known as a guanine quadruplex (G4) that is central to AV. In this work, we demonstrate that the role of RecQ in AV is independent of its ability to resolve G4s and that RecQ is incapable of unwinding the G4 in question. We propose a new model of RecQ’s role in AV where the G4 might recruit or orient RecQ to facilitate homologous recombination.
Laboratory Diagnosis of Sexually Transmitted Infections in Cases of Suspected Child Sexual Abuse
Authors: Qin Xuan , Melvin Ann J.
Published: November 2019

Laboratory diagnosis of microbial agents associated with sexually transmitted infections plays an important role in both the care of victims of child sexual abuse (CSA) and the investigation of suspected CSA incidents, with law enforcement implications. Rapid and sensitive test results prompt immediate actions to treat and protect the victimized children.
miR-541 potentiates the response of human hepatocellular carcinoma to sorafenib treatment by inhibiting autophagy
Authors: Xu Wen-Ping , Liu Jin-Pei , Feng Ji-Feng , Zhu Chang-Peng , Yang Yuan , Zhou Wei-Ping , Ding Jin , Huang Chen-Kai , Cui Ya-Lu , Ding Chen-Hong , Zhang Xin , Lu Bin , Xie Wei-Fen
Published: November 2019

Objective

Autophagy participates in the progression of hepatocellular carcinoma (HCC) and the resistance of HCC cells to sorafenib. We investigated the feasibility of sensitising HCC cells to sorafenib by modulating miR-541-initiated microRNA-autophagy axis.

Design

Gain- and loss-of-function assays were performed to evaluate the effects of miR-541 on the malignant properties and autophagy of human HCC cells. Autophagy was quantified by western blotting of LC3, transmission electron microscopy analyses and confocal microscopy scanning of mRFP-GFP-LC3 reporter construct. Luciferase reporter assays were conducted to confirm the targets of miR-541. HCC xenograft tumours were established to analyse the role of miR-541 in sorafenib-induced lethality.

Results

The expression of miR-541 was downregulated in human HCC tissues and was associated with malignant clinicopathologic phenotypes, recurrence and survival of patients with HCC. miR-541 inhibited the growth, metastasis and autophagy of HCC cells both in vitro and in vivo. Prediction software and luciferase reporter assays identified autophagy-related gene 2A (ATG2A) and Ras-related protein Rab-1B (RAB1B) as the direct targets of miR-541. Consistent with the effects of the miR-541 mimic, inhibition of ATG2A or RAB1B suppressed the malignant phenotypes and autophagy of HCC cells. Furthermore, siATG2A and siRAB1B partially reversed the enhancement of the malignant properties and autophagy in HCC cells mediated by the miR-541 inhibitor. More interestingly, higher miR-541 expression predicted a better response to sorafenib treatment, and the combination of miR-541 and sorafenib further suppressed the growth of HCC cells in vivo compared with the single treatment.

Conclusions

Dysregulation of miR-541-ATG2A/RAB1B axis plays a critical role in patients’ responses to sorafenib treatment. Manipulation of this axis might benefit survival of patients with HCC, especially in the context of the highly pursued strategies to eliminate drug resistance.
Association between particulate matter air pollution and lung cancer
Authors: Zhang Zhenyu , Zhu Dawei , Cui Bin , Ding Ruoxi , Shi Xuefeng , He Ping
Published: November 2019

Long-term exposure to particulate matter 2.5 μm (PM2.5) air pollution is associated with an increased risk of lung cancer. However, the evidence is limited in low-income and middle-income countries. We estimated the association between the incidence of lung cancer and PM2.5air pollution exposure in the Urban Employee Basic Medical Insurance (UEBMI) beneficiaries in China. A total of 16 483 new lung cancer cases diagnosed from 12 966 137 UEBMI beneficiaries from 36 cities between 2013 and 2016. The relative risk for lung cancer associated with a 10 µg/m3increase in 3-year PM2.5exposure was 1.12 (95% CI 1.00 to 1.26). The population attributable risk estimated for a reduction in PM2.5concentration to 35 µg/m3corresponded to a decrease of 14% in cases of lung cancer. Reducing PM2.5air pollution has a significant public health benefit.
Constraining the Inert Doublet Model using Vector Boson Fusion
Authors: Dercks Daniel , Robens Tania
Published: November 2019

In this work, we use a recast of the Run II search for invisible Higgs decays within Vector Boson Fusion to constrain the parameter space of the Inert Doublet model, a two Higgs doublet model with a dark matter candidate. When including all known theoretical as well as collider constraints, we find that the above can rule out a relatively large part in the $$m_H,\,\lambda _{345}$$mH,λ345 parameter space, for dark scalar masses $$m_H\,\le \,100\,{\mathrm{GeV}}$$mH≤100GeV. Including the latest dark matter constraints, a smaller part of parameter space remains which is solely excluded from the above analysis. We also discuss the sensitivity of monojet searches and multilepton final states from Run II.
Buchweitz’s equivalences for Gorenstein flat modules with respect to semidualizing modules
Authors: Hu Jiangsheng , Geng Yuxian , Wu Jinyong , Li Huanhuan
Published: November 2019

Let [Formula: see text] be a commutative Noetherian ring and [Formula: see text] a semidualizing [Formula: see text]-module. We obtain an exact structure [Formula: see text] and prove that the full subcategory [Formula: see text] of [Formula: see text] is a Frobenius category with [Formula: see text] the subcategory of projective and injective objects, where [Formula: see text] and [Formula: see text] (respectively, [Formula: see text]) is the subcategory of [Formula: see text]-Gorenstein flat (respectively, [Formula: see text]-flat [Formula: see text]-cotorsion) [Formula: see text]-modules. Then the stable category [Formula: see text] of [Formula: see text] and the singularity category [Formula: see text] of [Formula: see text] are also considered. As a consequence, we get that there is a Buchweitz’s equivalence [Formula: see text] if and only if [Formula: see text] is a part of some AB-context.
Isomorphism classes of commutative algebras generated by idempotents
Authors: Inoue Kazuyo , Kawai Hideyasu , Onoda Nobuharu
Published: November 2019

We study commutative algebras generated by idempotents with particular emphasis on the number of primitive idempotents. Let [Formula: see text] be an integral domain with the field of fractions [Formula: see text] and let [Formula: see text] be an [Formula: see text]-algebra which is torsion-free as an [Formula: see text]-module. We show that if [Formula: see text] satisfies the three conditions: [Formula: see text] is generated by idempotents over [Formula: see text]; [Formula: see text] is countably infinite dimensional over [Formula: see text]; [Formula: see text] has [Formula: see text] primitive idempotents for a nonnegative integer [Formula: see text], then [Formula: see text] is uniquely determined up to [Formula: see text]-algebra isomorphism. We also consider the case where [Formula: see text] has countably many primitive idempotents.
Some remarks on locally perfect rings
Authors: Zhou Dechuan , Kim Hwankoo , Zhang Xiaolei , Hu Kui
Published: November 2019

In this paper, the concept of almost projective covers is introduced. Using this concept, locally perfect rings are characterized. Also, the concepts of [Formula: see text]-almost projective modules, [Formula: see text]-almost projective covers, and [Formula: see text]-locally perfect rings are introduced. Then [Formula: see text]-locally perfect rings are characterized in terms of [Formula: see text]-almost projective modules and [Formula: see text]-almost projective covers, respectively.
An irreducibility question concerning modifications of Laguerre polynomials
Authors: Banerjee Pradipto , Bera Ranjan
Published: November 2019

This paper addresses a question recently posed by Hajir concerning the irreducibility of certain modifications [Formula: see text] of generalized Laguerre polynomials [Formula: see text] where [Formula: see text] is an integer. For a fixed [Formula: see text], we obtain lower bounds [Formula: see text] on [Formula: see text] in terms of [Formula: see text] such that [Formula: see text] is irreducible over the rationals for all [Formula: see text]. Furthermore, for [Formula: see text], it is shown that [Formula: see text] is either irreducible or is a product of a linear polynomial and a polynomial of degree [Formula: see text]. The set of circumstances in which [Formula: see text] has a linear factor for [Formula: see text], is completely described.