bluuebunny/crossref_metadata_2025 huggingface dataset:
Excitation and propagation of non-axisymmetric guided waves in a hollow cylinder
Authors: Li Jian , Rose Joseph L.
Published: July 2002

Excitation and propagation of non-axisymmetric guided waves in a hollow cylinder is studied by using the normal mode expansion method (NME). Different sources such as angle beam, tube end excitation with normal beam, and comb transducer possibilities are discussed based on the derivations of the NME method. Numerical calculations are focused on the case of angle beam partial loading. Based on the NME method, the amplitude coefficients for all of the harmonic modes are obtained. Due to the difference of phase velocities for different modes, the superimposed total field varies with propagating distances and hence makes particle displacement distribution patterns (angular profile) change with distance. This varying non-axisymmetric angular profile of guided waves represents a nonuniform energy distribution around the hollow cylinder and thus has an impact on the inspection ability of guided waves. The angular profiles of an angle beam source are predicted by theory and then verified by experiments. The predicted angular profiles also provide information for determining the transducer location to find defects in a certain position on the hollow cylinder.
Noise source identification in a rotary compressor: A multidisciplinary synergetic approach
Authors: Kim Han-Jun , Cho Young Man
Published: July 2002

The complex nature of noise/vibration generation and transmission in rotating machinery has made it indispensable to employ various techniques to identify the corresponding sources and paths. A theoretical approach via finite-element analysis (FEA), an experimental approach via direct measurement, and a signal processing approach via feature extraction of the measured data have all made significant contributions. Yet, there has not been much interdisciplinary effort among the three areas although their mutually complementary roles have long been recognized. In this paper, a synergetic approach is proposed to noise/vibration source and transmission path identification in order to take advantage of all the merits of the three different approaches. The proposed approach is discussed with a rotary compressor as a testbed. In the new approach, the experimentally measured sound intensity map is initially used to suggest the active radiation area, which guides us to instrument the rotary compressor at the suspected noise/vibration source positions. The collected data from the compressor is then processed to unravel the candidate source(s). Various signal processing techniques such as filtering, Hilbert transform, and fast Fourier transform are used to enhance the desired features buried in the experimental data. Finally, modal analysis via FEA and direct measurement further help to pinpoint the true source(s) and simultaneously verifies the conjecture following the experimental data processing.
Low-frequency reflection characteristics of the s0 Lamb wave from a rectangular notch in a plate
Authors: Lowe M. J. S. , Diligent O.
Published: July 2002

An analysis of the reflection of the fundamental Lamb mode s0 from surface-breaking rectangular notches in isotropic plates is presented. The results are obtained from finite element time domain simulations together with experimental measurements. Very good agreement is found between the simulations and the measurements. Results are shown for a range of notch widths and depths, including the special case of a crack, defined as a zero-width notch. An interference phenomenon is identified which explains the periodic nature of the reflection coefficient when plotted as a function of notch width. Finally, an analysis using the S-parameter approach and both low and high frequency asymptotic analyses yields physical explanations of the nature of the reflection behavior from the cracks. It is found that the low frequency (quasistatic) approximation may be used accurately for cracks up to about a quarter of the plate thickness, provided that the quasistatic crack-opening function is chosen such that bending of the plate is omitted. At higher frequencies and depths the functions tend towards the high frequency (ray theory) predictions but these are never accurate models within the nondispersive frequency range of the s0 mode.
The response of an elastically supported infinite Timoshenko beam to a moving vibrating mass
Authors: Mackertich Seroj
Published: July 2002

An analysis is made of the problem of vibrations of an infinite beam on elastic foundation excited by a moving and vibrating mass. The solution is presented within the framework of a beam theory which includes the effects of shear deformation and rotatory inertia. An example is provided where the displacement is calculated.
Spectral balance as a cue in the perception of linguistic stress
Authors: Sluijter Agaath M. C. , van Heuven Vincent J. , Pacilly Jos J. A.
Published: July 2002

In this study, the claim that intensity, as an acoustic operationalization of loudness, is a weak cue in the perception of linguistic stress is reconsidered. This claim is based on perception experiments in which loudness was varied in a naive way: All parts of the spectrum were amplified uniformly, i.e., loudness was implemented as intensity or gain. In an earlier study it was found that if a speaker produces stressed syllables in natural speech, higher frequencies increase more than lower frequencies. Varying loudness in this way would therefore be more realistic, and should bring its true cue value to the surface. Results of a perception experiment bear out that realistic intensity level manipulations (i.e., concentrated in the higher frequency bands) provide stronger stress cues than uniformly distributed intensity differences, and are close in strength to duration differences.
Dependence of ultrasonic attenuation and absorption in dog soft tissues on temperature and thermal dose
Authors: Damianou Christakis A. , Sanghvi Narendra T. , Fry Francis J. , Maass-Moreno Roberto
Published: July 2002

The effect of temperature and thermal dose (equivalent minutes at 43 °C) on ultrasonic attenuation in fresh dog muscle, liver, and kidney in vitro, was studied over a temperature range from room temperature to 70 °C. The effect of temperature on ultrasonic absorption in muscle was also studied. The attenuation experiments were performed at 4.32 MHz, and the absorption experiments at 4 MHz. Attenuation and absorption increased at temperatures higher than 50 °C, and eventually reached a maximum at 65 °C. The rate of change of tissue attenuation as a function of temperature was between 0.239 and 0.291 Np m−1 MHz−1 °C−1 over the temperature range 50–65 °C. A change in attenuation and absorption was observed at thermal doses of 100–1000 min, where a doubling of these loss coefficients was observed over that measured at 37 °C, presumably the result of changes in tissue composition. The maximum attenuation or absorption was reached at thermal dosages on the order of 107 min. It was found that the rate at which the thermal dose was applied (i.e., thermal dose per min) plays a very important role in the total attenuation absorption. Lower thermal dose rates resulted in larger attenuation coefficients. Estimations of temperature-dependent absorption using a bioheat equation based thermal model predicted the experimental temperature within 2 °C.
Thermoacoustic relaxation in a pin-array stack
Authors: Hayden M. E. , Swift G. W.
Published: July 2002

The pressure response p1 of a fixed quantity of He4 gas subjected to sinusoidal volume perturbations is studied experimentally. Thermal diffusion near solid boundaries causes the gas response to be neither adiabatic nor isothermal. The data are interpreted in terms of the thermal relaxation function fκ which relates p1 to the spatial average of the acoustic temperature profile. Comparison of a number of geometries allows us to accurately determine fκ for a thermoacoustic pin-array stack.
A model for binaural response properties of inferior colliculus neurons. I. A model with interaural time difference-sensitive excitatory and inhibitory inputs
Authors: Cai Hongmei , Carney Laurel H. , Colburn H. Steven
Published: July 2002

A model was developed that simulates the binaural response properties of low-frequency inferior colliculus (IC) neurons in response to several types of stimuli. The model incorporates existing models for auditory-nerve fibers, bushy cells in the cochlear nucleus, and cells in medial superior olive (MSO). The IC model neuron receives two inputs, one excitatory from an ipsilateral MSO model cell and one inhibitory from a contralateral MSO model cell. The membrane potential of the IC model neuron (and the other model neurons) is described by Hodgkin–Huxley type equations. Responses of IC neurons are simulated for pure-tone stimuli, binaural beat stimuli, interaural phase-modulated tones, single binaural clicks, and pairs of binaural clicks. The simulation results show most of the observed properties of IC discharge patterns, including the bimodal and unimodal interaural time difference (ITD) functions, sensitivities to direction and rate of change of ITD, ITD-dependent echo suppression, and early and late inhibitions in response to clicks. This study demonstrates that these response properties can be generated by a simple model incorporating ITD-dependent excitation and inhibition from binaural neurons.
State switched transducers: A new approach to high-power, low-frequency, underwater projectors
Authors: Larson Gregg D. , Rogers Peter H. , Munk Walter
Published: July 2002

In order to produce high-amplitude, low-frequency signals, an underwater transducer must generate a relatively large volume displacement. Since water exerts a large reaction force back on the transducer, “conventional wisdom” dictates that such a transducer would have to be a high Q resonant device and thus not be broadband. However, a transducer does not have to be broadband in the conventional sense to meet the requirements of communication and sonar systems. A transducer that is capable of instantaneously switching between two discrete frequencies is adequate for communication and transmission of coded signals; one that is capable of switching among several frequencies could produce the chirp signals commonly used in active sonars. Ordinarily, a broadband transducer is needed to accomplish the frequency switching rapidly. A way around this difficulty is the “state-switched” source concept originally proposed by Walter Munk in 1980 which permits instantaneous frequency switching of a high Q resonant transducer while always maintaining the resonance state. The objective of this research has been to investigate this novel approach to the design of high-power, low-frequency, broadband transducers for use in long-range underwater communication, active sonar, and underwater research applications. This paper presents a practical realization of a “state-switched” source.
Automated recognition of bird song elements from continuous recordings using dynamic time warping and hidden Markov models: A comparative study
Authors: Kogan Joseph A. , Margoliash Daniel
Published: July 2002

The performance of two techniques is compared for automated recognition of bird song units from continuous recordings. The advantages and limitations of dynamic time warping (DTW) and hidden Markov models (HMMs) are evaluated on a large database of male songs of zebra finches (Taeniopygia guttata) and indigo buntings (Passerina cyanea), which have different types of vocalizations and have been recorded under different laboratory conditions. Depending on the quality of recordings and complexity of song, the DTW-based technique gives excellent to satisfactory performance. Under challenging conditions such as noisy recordings or presence of confusing short-duration calls, good performance of the DTW-based technique requires careful selection of templates that may demand expert knowledge. Because HMMs are trained, equivalent or even better performance of HMMs can be achieved based only on segmentation and labeling of constituent vocalizations, albeit with many more training examples than DTW templates. One weakness in HMM performance is the misclassification of short-duration vocalizations or song units with more variable structure (e.g., some calls, and syllables of plastic songs). To address these and other limitations, new approaches for analyzing bird vocalizations are discussed.
Lamb wave assessment of fatigue and thermal damage in composites
Authors: Seale Michael D. , Smith Barry T. , Prosser W. H.
Published: July 2002

Among the various techniques available, ultrasonic Lamb waves offer a convenient method of evaluating composite materials. Since the Lamb wave velocity depends on the elastic properties of a structure, an effective tool exists to monitor damage in composites by measuring the velocity of these waves. Lamb wave measurements can propagate over long distances and are sensitive to the desired in-plane elastic properties of the material. This paper describes two studies which monitor fatigue damage and two studies which monitor thermal damage in composites using Lamb waves. In the fatigue studies, the Lamb wave velocity is compared to modulus measurements obtained using strain gage measurements in the first experiment and the velocity is monitored along with the crack density in the second. In the thermal damage studies, one examines samples which were exposed to varying temperatures for a three minute duration and the second includes rapid thermal damage in composites by intense laser beams. In all studies, the Lamb wave velocity is demonstrated to be an excellent method to monitor damage in composites.
The influence of liquid temperature on the sonoluminescence hot spot
Authors: Vuong Vi Q. , Fyrillas Marios M. , Szeri Andrew J.
Published: July 2002

An explanation is provided for the influence of relatively small changes in liquid temperature on the hot spot within a sonoluminescence bubble. This influence derives from a change in the (stable) equilibrium mass of the bubble due to a variation of the gas solubility in the liquid with temperature. If the acoustic drive amplitude is held constant, a change in the liquid temperature has a large or small effect depending on the variability of the solubility with temperature. For a gas like xenon, which has rapidly decreasing solubility in water with increasing temperature, a decrease in water temperature shifts the stable mass exchange equilibrium to a smaller bubble size. This increases the ratio of maximum to minimum bubble radius over an acoustic cycle, resulting in a much higher hot spot temperature. In contrast helium has very little variation of solubility with temperature near room temperature; therefore the hot spot temperature is relatively insensitive to variations in the liquid temperature outside a helium bubble.
Wave propagation in fluids contained in finite-length anisotropic viscoelastic pipes
Authors: Yu Jinghong , Kojima Eiichi
Published: July 2002

Wave propagation characteristics are studied of a fluid-filled, finite-length anisotropic viscoelastic pipe—a flexible hydraulic hose. An analytical model in transfer matrix form is developed for relating the pressure and flow ripples at hose upstream and downstream. The anisotropic viscoelasticity of the hose wall, the coupled vibration of the hose and the fluid, and the effect of possible longitudinal resonances of the finite-length hose are considered. The static mechanical properties and frequency-dependent mechanical properties of the hose wall are determined by means of specially designed static expansion method and optimal searching method separately. Experimental confirmation is made over a wide frequency range by using an experimental procedure for measuring the transfer matrix parameters. By comparing the predicted and measured results of the hoses with different lengths, it is shown that the model yields fairly good results in a frequency range of around 0–3 kHz and even may predict the influence of longitudinal resonances of the hose wall on the wave propagation of fluid in the hose. The effectiveness of the experimental methods and procedure proposed here are also verified.
FDTD simulation of finite-amplitude pressure and temperature fields for biomedical ultrasound
Authors: Hallaj Ibrahim M. , Cleveland Robin O.
Published: July 2002

Full wave simulations provide a valuable tool for studying the spatial and temporal nature of an acoustic field. One method for producing such simulations is the finite-difference time-domain (FDTD) method. This method uses discrete differences to approximate derivatives in the governing partial differential equations. We used the FDTD method to model the propagation of finite-amplitude sound in a homogeneous thermoviscous fluid. The calculated acoustic pressure field was then used to compute the transient temperature rise in the fluid; the heating results from absorption of acoustic energy by the fluid. As an example, the transient temperature field was calculated in biological tissue in response to a pulse of focused ultrasound. Enhanced heating of the tissue from finite-amplitude effects was observed. The excess heating was attributed to the nonlinear generation of higher-frequency harmonics which are absorbed more readily than the fundamental. The effect of nonlinear distortion on temperature rise in tissue was observed to range from negligible at 1 MPa source pressure to an 80% increase in temperature elevation at 10 MPa source pressure.
Measurement of transient response of rooms and comparison with geometrical acoustic models
Authors: Suh J. S. , Nelson P. A.
Published: July 2002

The transient responses of rooms obtained from measurements and geometrical room acoustic models are compared. The conventional image model was modified in order to include interference in the modeling process by accounting for the amplitude and phase changes produced at each reflection. This “phase image model” has the capability to find the simulated pressure impulse response of a modeled room. In order to validate this model, some theoretical analyses and measurements were first carried out on a single reflecting surface. Finally the pressure impulse responses and energy impulse responses were measured in real rooms and these were compared with those from the phase image model and the conventional models. It is shown that the inclusion of complex reflections in the phase image model greatly increases the accuracy of the predictions. In this work Gabor pulses are used as the optimal source strength signals, enabling comparison between measurements and room acoustic models.
The relative perceptual distinctiveness of initial and final consonants in CVC syllables
Authors: Redford Melissa A. , Diehl Randy L.
Published: July 2002

Among the world’s languages, syllable inventories allowing only initial consonants predominate over those allowing both initial and final consonants. Final consonants may be disfavored because they are less easy to identify and/or more difficult to produce than initial consonants. In this study, two perceptual confusion experiments were conducted in which subjects identified naturally produced consonant–vowel–consonant syllables in different frame sentences. Results indicated that initial consonants were significantly more identifiable than final consonants across all conditions. Acoustic analyses of the test syllables indicated that the relative identifiability of initial and final consonants might be explained in terms of production differences as indicated by the greater acoustic distinctiveness of initial consonants.
Applications of waveguide-type base functions for the eigenproblems of two-dimensional cavities
Authors: Kim Yoon Young , Kim Dong Kyun
Published: July 2002

An acoustic modal analysis technique useful for two-dimensional cavities of general shapes is developed as an extension of the technique developed earlier by Kim and Kang [J. Acoust. Soc. Am. 99, 2938–2946 (1996)] for the modal analysis of convex membranes. Both Neumann and Dirichlet problems can be solved with the present choice of cosinusoidally varying waveguide-type functions instead of sinusoidally varying waveguide-type functions adopted earlier [J. Acoust. Soc. Am. 99, 2938–2946 (1996)]. A cavity subdivision technique for general nonconvex cavities overcomes the limitation of the earlier technique useful only for convex cavities. Successful applications of the present technique are demonstrated in some practical two-dimensional cavity problems. The present technique is potentially a very efficient technique in handling higher eigenmodes.
Numerical simulation of pulse propagation in nonlinear 1-D media
Authors: Scalerandi M. , Delsanto P. P. , Chiroiu C. , Chiroiu V.
Published: July 2002

The problem of convergence of finite difference (FD) schemes for simulating the propagation of pulses in nonlinear media is analyzed. In order to establish the reliability of the numerical procedure, different FD schemes are considered and compared among themselves, with the results of a Von Neumann analysis and with the analytical solution (when available). Examples of application of the method are also provided: e.g., the propagation of semi-infinite waves and pulses in active media with periodic and exponentially decaying nonlinearities.
A model for longitudinal and shear wave propagation in viscoelastic media
Authors: Szabo Thomas L. , Wu Junru
Published: July 2002

Relaxation models fail to predict and explain loss characteristics of many viscoelastic materials which follow a frequency power law. A model based on a time-domain statement of causality is presented that describes observed power-law behavior of many viscoelastic materials. A Hooke’s law is derived from power-law loss characteristics; it reduces to the Hooke’s law for the Voigt model for the specific case of quadratic frequency loss. Broadband loss and velocity data for both longitudinal and shear elastic types of waves agree well with predictions. These acoustic loss models are compared to theories for loss mechanisms in dielectrics based on isolated polar molecules and cooperative interactions.
Rheology of Suspensions in Polymeric Liquids
Authors: Metzner A. B.
Published: July 2002

This paper reviews the flow behavior of concentrated suspensions as may be of interest in the processing of composites and similar polymeric materials. Succinct synopses are arranged at the end of each section. In general, the state of the art is a good one: a small number of experiments on a new formulation frequently suffice for a general prediction of flow behavior when solids are suspended in viscous molten polymers, and in many instances, even a priori predictions of the viscosity are possible. Less viscous systems are much more difficult; several remaining problems and research areas are identified.
Granular collision lubrication
Authors: Yu Chih-Ming , Craig Kevin , Tichy John
Published: July 2002

The flow of powder or granules has been proposed as a mechanism of lubrication suitable for high-temperature applications where conventional liquid lubrication fails. This study is primarily experimental with a simplified theory presented for interpreting the data. Two key features are present which seem to be additive: (1) a collisional normal stress generated by kinetic energy of the particles, and (2) a lubrication normal stress due to converging surfaces. Experiments are conducted in an annular shear cell with sliding motion between opposing surfaces. The shear surface may be flat or contain three sloping regions with a step. Normal stress (load) and shear stress (friction) are proportional to shear rate squared. In the case of inclined surfaces, stresses are also proportional to the surface slope squared.
Particle migration in tube flow of suspensions
Authors: Han Minsoo , Kim Chongyoup , Kim Minchul , Lee Soonchil
Published: July 2002

In this research, we investigated the migration of particles in the tube flow of suspension for a wide range of particle loading (φ0) and particle Reynolds number (Rep), using a magnetic resonance imaging (MRI) technique. The suspension consisted of nearly monodisperse polymethylmethacrylate spheres in a density matched Newtonian fluid. The volume fraction of the solid was 0.06–0.40. Both the velocity and the concentration distributions were measured under fully developed conditions. It has been found that, when φ0 was small (⩽0.1) and Rep was not small (>≈0.2), the particles moved toward the position at a distance of 0.5–0.6 R (tube radius) from the tube axis and the velocity profile was parabolic. When φ0=0.4, particles always moved toward the center of the tube and the velocity profile was blunted. The degree of blunting was larger for smaller Rep. Between these two limiting cases, the particle migration was dependent on Rep. When Rep is small the particles move toward the tube axis regardless of φ0. When φ0 is 0.2–0.3 and Rep>≈0.2, particles are concentrated both at the center and at the middle of the tube axis and tube wall. The velocity profile keeps the parabolic form unless the particles are concentrated regardless of Rep. Apparent wall slip is not observed except for the case of φ0=0.40. It is suggested that, when the particle Reynolds number is larger than 0.1, the inertial effect cannot be neglected regardless of the average particle concentration.
Curvilinear flows of noncolloidal suspensions: The role of normal stresses
Authors: Morris Jeffrey F. , Boulay Fabienne
Published: July 2002

The role of normal stresses in causing particle migration and macroscopic spatial variation of the particle volume fraction φ in a mixture of rigid neutrally buoyant spherical particles suspended in Newtonian fluid is examined for curvilinear shear flows. The problem is studied for monodisperse noncolloidal Stokes-flow suspensions, i.e., for conditions of low-Reynolds-number flow and infinite Péclet number, Pe=O(ηγ̇a3/kT), where η is the suspending fluid viscosity, γ̇ is the shear rate, a is the particle radius, and kT is the thermal energy. Wide-gap Couette, parallel-plate torsional, and cone-and-plate torsional flows are studied. The entire φ dependence of the compressive shear-induced normal stresses is captured by a “normal stress viscosity” ηn(φ), which vanishes (as φ2) at φ=0 and diverges at maximum packing in the same fashion as does the shear viscosity ηs(φ). Anisotropy of the normal stresses arising from the presence of the particles is modeled as independent of φ, so that ratios of any two particle contributions to the bulk normal stress components are constants, Σ22p/Σ11p=λ2 and Σ33p/Σ11p=λ3; the standard convention of (1,2,3) denoting the (flow, gradient, vorticity) directions is used so that, for example, Σ11p is the normal component of the particle stress Σp in the flow direction. Predictions for the steady and unsteady flows are presented to demonstrate the influence of variation of the normal stress anisotropy parameters λ2 and λ3, the rheological functions ηs and ηn, and the sedimentation hindrance function used to represent the resistance to relative motions of the phases during migration. Comparison with available experimental data shows that a single set of parameters for the rheological model is able to describe all qualitative features of the observed migrations in the flows considered.
Nanosized Fat Emulsion Injection Modulating Local Microenvironment Promotes Angiogenesis in Chronic Wound Healing
Authors: Xian Caihong , Zhang Zhen , You Xinru , Fang Yifen , Wu Jun
Published: May 2022

The current treatment for chronic diabetic wounds is costly for patients and society. The proinflammatory state and impaired vascular condition are the main factors that hamper diabetic wound healing. In this study, fat emulsion (FE), a nanosized product clinically used to provide nutrition and energy to patients through vein injection, is evaluated for its diabetic wound healing capability for the first time. The nanosized FE is mixed with methacrylated hyaluronic acid (HA–MA) hydrogel to form an anti‐inflammatory and angiogenic FE/HA–MA hybrid hydrogel dressing to accelerate the diabetic wound closure. Results of RT‐qPCR analysis and ELISA demonstrate that the FE exerts excellent anti‐inflammatory effects by significantly downregulating the expression of proinflammatory cytokines tumor necrosis factor‐α (TNF‐α) and interleukin‐1β (IL‐1β), both in vitro and in vivo. The endothelial tube formation and scratch assays reveal that the FE promotes angiogenesis and cell migration, respectively, by releasing vascular endothelial growth factor A. The in vivo diabetic wound mouse model confirms an increased blood vessel density, healing rate, tissue epithelialization, and collagen deposition in the FE/HA–MA hybrid hydrogel dressing group compared to the control group. These findings may provide a promising and economic product and strategy for diabetic wound treatment in the clinic.
Initial guess estimation and fast solving of petroleum complex molecular reconstruction model
Authors: Guan Dong , Zhang Linzhou
Published: May 2022

We proposed a fast method to solve the petroleum molecular reconstruction problem via initial guess estimation coupled with local optimization algorithm. A virtual oil database was constructed. After inputting the bulk properties of the target oil, several virtual oils with similar bulk properties were selected and their model parameters were used as the initial guesses. Subsequently, we proved that by using a local optimization method, the optimal model parameters can be rapidly obtained. The diesel and vacuum gas oil compositional models were exemplified as case studies. The results show that the proposed method presented faster computational time, which is within the range of 20–50 times that of frequently used global algorithms. Moreover, the optimal solution of the proposed method exhibited higher accuracy. In addition, the effect of the number of virtual oils and the parallel computation performance were also investigated.
Overcoming Pilotitis in Digital Medicine at the Intersection of Data, Clinical Evidence, and Adoption
Authors: Egermark Mathias , Blasiak Agata , Remus Alexandria , Sapanel Yoann , Ho Dean
Published: May 2022

Worldwide, digital medicine technologies are being developed at a rapid rate. While these digital medicine technologies offer the potential to transform and revolutionize health care, many are at risk of stalling and remaining in the pilot stage, known as “pilotitis,” thus never reaching true potential. Therefore, overcoming “pilotitis” to increase the uptake of digital medicine technologies is a global concern. To date, several authors have proposed solutions to overcome various barriers owing to the “pilotitis” of digital medicine technologies, such as regulatory frameworks and patients’ data ownership; however, many areas require further consideration. This perspective piece identifies three barriers to the adoption and implementation of digital medicine technologies and proposes approaches for how to overcome them. Addressing such barriers may provide a pathway to success for digital medicine technologies to improve patient outcomes and increase the efficiency of healthcare delivery.
Undiagnosed disease program in South Africa: Results from first 100 exomes
Authors: Moosa Shahida , Coetzer Kimberly Christine , Lee Eugene , Seo Go Hun
Published: May 2022

The Undiagnosed Disease Program in South Africa (UDP) sought to prospectively evaluate the clinical utility of exome sequencing (ES) in a phenotypically diverse, multi‐ethnic cohort of South African patients with suspected rare genetic disorders. ES was undertaken in 100 sequential patients (93 singletons, 3 duos, and 4 trios) recruited to the UDP at Stellenbosch University. The data were analyzed through two separate bioinformatics pipelines (EVIDENCE from 3 billion and our in‐house pipeline). A definitive diagnosis could be reached in 51% (51/100) patients, with 46% (46/100) patients having either pathogenic or likely pathogenic single‐nucleotide variants/indels (SNVs/indels), and 5 patients with likely‐pathogenic copy number variants (CNVs) (5/100). The CNVs were subsequently confirmed on microarray or MLPA analysis. Detailed phenotyping and HPO terms enabled analysis and variant identification. Twenty‐five novel variants in 22 genes are reported here. We provide data from the first year of this UDP and show that even amongst mainly singletons from an understudied, diverse African population, ES is a valuable diagnostic tool, especially if it includes CNV analysis. The remaining undiagnosed patients present a unique opportunity for further research and novel gene discovery.
Integrative Approach to Predict Severity in Nonketotic Hyperglycinemia
Authors: Kuseyri Hübschmann Oya , Juliá‐Palacios Natalia Alexandra , Olivella Mireia , Guder Philipp , Zafeiriou Dimitrios I. , Horvath Gabriella , Kulhánek Jan , Pearson Toni S. , Kuster Alice , Cortès‐Saladelafont Elisenda , Ibáñez Salvador , García‐Jiménez Maria Concepción , Honzík Tomáš , Santer René , Jeltsch Kathrin , Garbade Sven F. , Hoffmann Georg F. , Opladen Thomas , García‐Cazorla Ángeles
Published: May 2022

Objective

Glycine encephalopathy, also known as nonketotic hyperglycinemia (NKH), is an inherited neurometabolic disorder with variable clinical course and severity, ranging from infantile epileptic encephalopathy to psychiatric disorders. A precise phenotypic characterization and an evaluation of predictive approaches are needed.

Methods

Longitudinal clinical and biochemical data of 25 individuals with NKH from the patient registry of the International Working Group on Neurotransmitter Related Disorders were studied with in silico analyses, pathogenicity scores, and molecular modeling of GLDC and AMT variants.

Results

Symptom onset (p < 0.01) and diagnosis occur earlier in life in severe NKH (p < 0.01). Presenting symptoms affect the age at diagnosis. Psychiatric problems occur predominantly in attenuated NKH. Onset age ≥ 3 months (66% specificity, 100% sensitivity, area under the curve [AUC] = 0.87) and cerebrospinal fluid (CSF)/plasma glycine ratio ≤ 0.09 (57% specificity, 100% sensitivity, AUC = 0.88) are sensitive indicators for attenuated NKH, whereas CSF glycine concentration ≥ 116.5μmol/l (100% specificity, 93% sensitivity, AUC = 0.97) and CSF/plasma glycine ratio ≥ 0.15 (100% specificity, 64% sensitivity, AUC = 0.88) are specific for severe forms. A ratio threshold of 0.128 discriminates the overlapping range. We present 10 new GLDC variants. Two mild variants resulted in attenuated, whereas 2 severe variants or 1 mild and 1 severe variant led to severe phenotype. Based on clinical, biochemical, and genetic parameters, we propose a severity prediction model.

Interpretation

This study widens the phenotypic spectrum of attenuated NKH and expands the number of pathogenic variants. The multiparametric approach provides a promising tool to predict disease severity, helping to improve clinical management strategies. ANN NEUROL 2022;92:292–303
High Conflicts as Wicked Problems from the Perspective of Family Counsellor and Child Welfare Services in Norway
Authors: Heggdalsvik Inger Kristin , Lorås Lennart , Samsonsen Vibeke
Published: May 2022

This article explores professionals’ understanding and experiences of parental high conflicts in Norwegian family counsellor and child welfare services. The data were analysed using reflexive thematic analysis, examining four focus group interviews with a total of 24 professionals. We used tame and wicked problems as a theoretical frame of reference in order to discuss how high conflict cases can be understood. The analysis shows that the complexity and experiences of high conflicts challenge professionals in their assessments and development of solutions. Our conclusion is that the nature of the complexity, unpredictability, and instability of high conflicts fits within the framework of wicked problems.
Clinical Issues—June 2022
Authors: Jones Emily
Published: May 2022

THIS MONTH

Electrostatic precipitator device use during laparoscopic surgery

Key words: electrostatic precipitation (ESP), surgical smoke precipitator, anions, visual field, medical device reporting (MDR).

Removal of used flammable skin antisepsis materials

Key words: flammable liquid antiseptics, National Fire Protection Association (NFPA), fire prevention, fire risk, patient care vicinity.

Ocular protection for patients with eyelash extensions

Key words: ocular injury, eyelash extensions, eye protection, lagophthalmos, intraocular pressure.

Perioperative nursing care of the patient with Raynaud’s phenomenon

Key words: ischemia, vasospasm, comfort measures, hypothermia, complementary care.
Conductive polycarbonate composites prepared by a ternary polymer blend approach involving sea‐island‐type interfacial carbon black networks
Authors: Li Hansong , Tuo Xinlin , Xing Ziyi , Guo Bao‐Hua , Yu Jian , Guo Zhao‐Xia
Published: May 2022

Ternary blends containing one major and two minor components are a common type of polymer blends, however, they have never been used to improve the electrical conductivity of polymer composites. Herein, polycarbonate (PC)/nylon‐poly(m‐xylene adipamide) (MXD6)/poly(ethylene terephthalate) (PET) (70/15/15) ternary blend is used to improve the conductivity of PC by forming sea‐island type interfacial carbon black (CB) networks. The phase change of PET from island to continuous structure, caused by the formation of CB networks at PET/MXD6 interface, is the key of success. The electrical percolation threshold of CB is much smaller than that in neat PC (only a ninth). Rheological investigation is carried out to confirm the formation of CB networks. The static mechanical properties of PC/MXD6/PET (70/15/15)‐2 vol% CB composite are evaluated by tensile testing, showing improved stiffness and strength, compared with the corresponding ternary blend, neat PC, and PC‐2 vol% CB composite.
Cover Image, Volume 16, Issue 3
Authors: Phillips Steven D. , Jones Susanne B. , Meyer Pimphan A. , Snowden‐Swan Lesley J.
Published: May 2022

The cover image is based on the Research Article Techno‐economic analysis of cellulosic ethanol conversion to fuel and chemicals by Steven Phillips et al., https://doi.org/10.1002/bbb.2346.

image
Einsatz von Hydrophobierungen nach der TR Instandhaltung des DIBt – Vorgehen aus der Perspektive des Planers und Praxisbeispiel
Authors: Schießl‐Pecka Angelika , Strehlein Doris
Published: May 2022

Nach der Technischen Regel Instandhaltung (TR IH) des Deutschen Instituts für Bautechnik (DIBt) [1], die bereits in einigen Bundesländern bauaufsichtlich eingeführt ist, ist im Gegensatz zum Teil 1 der Instandsetzungsrichtlinie des DAfStb [2] auch die Verwendung von Hydrophobierungen bzw. OS1‐Systemen zum Schutz gegen das Eindringen von Stoffen, zur Regulierung des Wasserhaushalts von Beton und zur Erhöhung des elektrolytischen Widerstands von Beton (bei carbonatisierungsinduzierter Bewehrungskorrosion) möglich. Im vorliegenden Beitrag wird ein Überblick über die am Markt erhältlichen Produktgruppen an Hydrophobierungen auf Silan‐ oder Siloxan‐Basis gegeben. Da der Planer nach der TR IH Auftragsmengen und Eindringtiefen vorgeben muss, werden das Vorgehen zur Bestimmung von Mindestauftragsmengen und Mindesteindringtiefen skizziert und entsprechende Laborprüfungen zur Bestimmung der Mindestwerte vorgestellt. Weiterhin werden Hinweise zur Planung und Qualitätssicherung während der Bauausführung gegeben. Eine während der Nutzung möglicherweise nachlassende Wirkung einer Hydrophobierung muss gemäß TR IH durch Kontrollmessungen im Instandhaltungsplan berücksichtigt werden. In diesem Zusammenhang werden verschiedene Möglichkeiten erläutert, mit denen ein solcher Wirkungsnachweis möglich ist. Abschließend wird ein Praxisbeispiel vorgestellt.
Characterizing biological macromolecules with attenuated total reflectance–Fourier transform infrared spectroscopy provides hands‐on spectroscopy experiences for undergraduates
Authors: Helburn Robin , Nolan Kathleen
Published: May 2022

Infrared (IR) spectra of biologically derived materials display distinct absorption bands correlating to individual macromolecules: protein, polysaccharide, lipid, and nucleic acids. A series of experiments aimed at teaching qualitative bioorganic spectroscopy using attenuated total reflectance (ATR) Fourier transform infrared (IR) with biological polymers as samples is proposed. Labs targeting 1st and 4th year undergraduate students at St. Francis College are being developed. During 2014 ➔ 2017, an integrated biology/chemistry exercise featuring elementary spectroscopy as an addition to an existing lab on light microscopy was administered to three sections of a 1st year general biology course. Students were taught the concept of a spectral fingerprint and to identify carbohydrate and protein based materials by looking for key vibrational bands. The success of that effort as determined by the results of an assessment quiz became the motivation for developing an advanced 4th year exercise involving four macromolecules. In a trial lab (Spring 2019) students gathered reference spectra from materials homogeneous in a single biopolymer followed by spectra of whole tissues which they were expected to fully characterize. Assessment data suggest that 1st year students benefited most from the experience. A detailed discussion of reference and sample spectra (as obtained by students) and relevant bond vibrations along with suggestions for instructors are presented.
The Milan System classification of Warthin tumor: A large institutional study of 124 cases highlighting cytologic features that limit definitive interpretation
Authors: Torous Vanda F. , Faquin William C.
Published: May 2022

BACKGROUND

Fine‐needle aspiration (FNA) is highly accurate for the diagnosis of Warthin tumor (WT). However, there is a minor subset of WT cases that are more challenging to interpret. The goal of this study is to identify factors that limit definitive diagnosis of WT on FNA.

METHODS

All WT surgical specimens diagnosed during a 6.5‐year study period were retrospectively identified and the preceding cytologic specimen diagnostic categories were analyzed. Of particular interest were WT cases with indeterminate or malignant interpretations. Cases that noted squamous or mucinous change in either the surgical or cytologic reports were also reviewed.

RESULTS

A total of 157 WT surgical specimens were identified, with 124 (79.0%) having prior FNAs. The distribution of cytologic diagnostic categories was 12 (9.7%) nondiagnostic, 10 (8.1%) nonneoplastic, 13 (10.5%) atypia of undetermined significance (AUS), 82 (66.1%) neoplasm: benign, 4 (3.2%) salivary gland neoplasm of uncertain malignant potential (SUMP), 2 (1.6%) suspicious for malignancy, and 1 (0.8%) malignant. Of the 20 cases in indeterminate/malignant categories, a majority noted either squamoid (9 of 20) or mucinous (2 of 20) changes. The remainder noted scant cellularity as a limiting factor to interpretation. Additionally, 27 cases mentioned squamous or mucinous change in the surgical or cytology report, with a wide spectrum of cytologic categorization including 2 (7.4%) nondiagnostic, 2 (7.4%) nonneoplastic, 7 (25.9%) AUS, 8 (29.6%) neoplasm: benign, 4 (14.8%) SUMP, 2 (7.4%) suspicious for malignancy, and 1 (3.7%) malignant.

CONCLUSIONS

This study identified 2 key causes for indeterminate or misclassification of WT on FNA: specimen hypocellularity and metaplastic changes. Recognition of the potential for squamous and mucinous metaplastic changes combined with observance of some helpful diagnostic clues such as the presence of crystalloids may aid in preventing diagnostic pitfalls.;
Cognitive Long‐range: Towards efficient public communication infrastructure for Internet of Things
Authors: Mousavi Seyed Mehdi , Khademzadeh Ahmad , Rahmani Amir Masoud
Published: May 2022

The most common Internet of Things (IoT) scenarios entail devices with limited energy resources and need to be connected to the Internet via wireless networks. This has driven the recent development of low‐power wide‐area networks (LPWANs) and the rise of the Long Range (LoRa) technology. The LoRa protocol has a simple modulation scheme that ensures low power consumption, high convergence, and resistance against interference. In most LPWAN technologies, several physical layer challenges arise, such as low data rates, spectral inefficiency, and increased interference. As a physical layer solution, the cognitive radio (CR) offers a possible way of resolving these challenges. CR allows wireless networks to operate without the need for a dedicated spectrum. Regarding the variety of end‐user requirements, developing a public communication network that can support such diverse and heterogeneous applications is necessary to reduce the implementation costs than developing a dedicated communication network for each application. This paper proposes a Cognitive LoRa (C‐LoRa) protocol that utilizes unlicensed and licensed frequencies as well as interference mitigation to improve the QoS of LoRa. To extract the priority list of traffic patterns, C‐LoRa incorporates the Analytic Hierarchy Process (AHP) algorithm. The priority list enables real‐time applications to receive optimal spectrum allocation. C‐LoRa can be efficiently implemented as a public communication infrastructure for heterogeneous IoT devices. The addition of licensed channels improves the overall QoS and decreases the average waiting time in queues. The platform layer of C‐LoRa consists of a cognitive engine that sends traffic priority lists to cognitive spectrum allocators. The IoT application servers are connected to the cloud platform layer via SNMP, HTTP, and other desired protocols. Access gateways equipped with a cognitive spectrum allocator are always connected to a power supply and serve as a transparent bridge to the cognitive engine at the platform layer, converting RF packets to IP packets and vice versa.
A comprehensive analytical perspective of ASEP for Beaulieu‐Xie fading channels
Authors: Bilim Mehmet
Published: May 2022

This study presents the average symbol error probability (ASEP) performance of a single‐input single‐output communication with imperfect phase error (IPE) and without IPE over the Beaulieu‐Xie fading channels. The Beaulieu‐Xie fading model is proposed recently and it is a popular characterization for the line‐of‐sight and non‐line‐of‐sight environments. The proposed theoretical analysis, which is based on the probability density function, is enough general and applicable in some real‐life scenarios. For both cases, closed‐form exact, approximate, and asymptotic expressions are derived for the ASEP of different modulation types. Finally, exact simulations have been introduced to confirm the accuracy of the theoretical findings obtained and present insights into the considered scheme performance.
Research on the investment decisions of PV micro‐grid enterprises under carbon trading mechanisms
Authors: Yu Guanyi , Wang Kai , Hu Yumeng , Chen Weidong
Published: May 2022

Achieving carbon neutrality targets requires substantial financial support. Effective utilization of renewable energy is an essential means of promoting energy‐saving and emission reduction to realize a green and circular economy. This paper combines carbon trading mechanisms with the operational mode of Chinese micro‐grid enterprises. This method uses the real options theory to construct an investment decision model for photovoltaic (PV) micro‐grid enterprises. The study aims to analyze the impact of carbon trading revenue on a numerical simulation of PV micro‐grid enterprise investment decisions. The findings demonstrate that when projected growth rates, volatility standard deviations, and risk‐free interest rates rise in the carbon trading market, the carbon price threshold rises, causing businesses to seek out investment opportunities with higher future carbon prices. The increase of micro‐grid generation technology acceptance probability, the availability of resources to meet generation investment requirements, and the generation project cycle will decrease the carbon price threshold and accelerate enterprise investment. Studying the influence of carbon trading prices on micro‐grid investment has specific guidance and practical significance for future government subsidy policies and the investment strategies of grid enterprises.