bluuebunny/crossref_metadata_2025 huggingface dataset:
PELICAN: a pricing mechanism for the electronic distribution of materials to the higher education community
Authors: Hardy Rachel , Oppenheim Charles , Rubbert Iris
Published: July 2002

PELICAN (Pricing Experiment Library Information Co‐operative Network) is a Joint Information Systems Committee‐funded project intended to develop an understanding of possible charging mechanisms for distributing commercially published digitized texts to students. The paper discusses the background to the project and sets out its aims and intentions within the context of ongoing dialogues between rights holders and the higher and further education communities. A brief description of the methodology to be adopted and the likely benefits for all stakeholders of establishing a mutually acceptable business and pricing model for the digitization of printed texts in UK higher education is presented.
On‐demand publishing in the Humanities: project
Authors: Sykes Phil
Published: July 2002

This article describes the ‘On‐Demand Publishing in the Humanities’ project, funded by JISC as part of the eLib programme, at Liverpool John Moores University. The principal aims of the project were to develop a ‘cheap and cheerful’ model for networking electronic texts, to develop a model agreement for the networking of copyright texts for use with publishers, and to shed light on the problems and benefits of on‐demand publishing for all the stakeholders involved. The article sets out the project methods, describes the extent to which the aims of the project have been fulfilled, analyses the reactions of end‐users to the materials, and attempts an assessment of the current viability of on‐demand publishing as a means of supplying copyright texts to students.
Publisher—library relationships in the digital environment
Authors: Cox John
Published: July 2002

STM represents 250 publishing companies and learned societies, and recognizes that the advent of digital networks affects authors, publishers, librarians, and readers. Dialogue between publishers and librarians is essential to creating the sense of partnership and open‐mindedness needed to meet the future needs of scholarship and research. Publishers and librarians have complementary roles and responsibilities, serving the same needs and facing similar challenges. The interests of publishers and librarians need to be rebalanced in order to seize the benefits of digital information flow. Legislation provides a framework of copyright, privacy, competition, and consumer law that protects against misuse while facilitating the flow of information from author to reader. If laws need to be amended, such changes should be made on the basis of the mutual agreement of all members of the community. There is much to be achieved without legislative change. Neither publishers nor librarians should shy away from the issues that divide them, especially the scope of fair use and the exchange of copyright information between libraries. A more detailed analysis of the impact of copyright exemptions is needed. The development of a predictable licensing environment and the testing of new business models requires co‐operation between publishers and librarians, and leads to better mutual understanding. STM seeks dialogue with libraries and with other members of the research and scholarly communities in order to meet the challenges, opportunities, and expectations created by the digital environment.
A Multivariate Faa di Bruno Formula with Applications
Authors: Constantine G. , Savits T.
Published: July 2002

A multivariate Faa di Bruno formula for computing arbitrary partial derivatives of a function composition is presented. It is shown, by way of a general identity, how such derivatives can also be expressed in the form of an infinite series. Applications to stochastic processes and multivariate cumulants are then delineated.
Multidimensional stability of planar travelling waves
Authors: Kapitula Todd
Published: July 2002

The multidimensional stability of planar travelling waves for systems of reaction-diffusion equations is considered in the case that the diffusion matrix is the identity. It is shown that if the wave is exponentially orbitally stable in one space dimension, then it is stable for

x
∈

R

n

,

n
≥
2

x\in \mathbf {R}^n,\,n\ge 2

. Furthermore, it is shown that the perturbation of the wave decays like

t

−
(
n
−
1
)

/

4

t^{-(n-1)/4}

as

t
→
∞

t\to \infty

. The result is proved via an application of linear semigroup theory.
Convergence of a random walk method for a partial differential equation
Authors: Lu Weidong
Published: July 2002

A Cauchy problem for a one–dimensional diffusion–reaction equation is solved on a grid by a random walk method, in which the diffusion part is solved by random walk of particles, and the (nonlinear) reaction part is solved via Euler’s polygonal arc method. Unlike in the literature, we do not assume monotonicity for the initial condition. It is proved that the algorithm converges and the rate of convergence is of order

O
(
h
)

O(h)

, where

h
h

is the spatial mesh length.
Matrix representations and the Teichmüller space of the twice punctured torus
Authors: Button J.
Published: July 2002

We realise the Teichmüller space of the twice-punctured torus as a set of triples of matrices that are suitably normalised. As a consequence, we see the space as a simple open subset of

R

4

\mathbb R^4

which is obtained directly from the matrix entries. We also discuss the connection between this representation and the one in terms of the traces of elements.
The imd gene is required for local Cecropin expression in Drosophila barrier epithelia
Authors: Önfelt Tingvall Tove , Roos Erik , Engström Ylva
Published: July 2002

Surfaces of higher eukaryotes are normally covered with microorganisms but are usually not infected by them. Innate immunity and the expression of gene‐encoded antimicrobial peptides play important roles in the first line of defence in higher animals. The immune response in Drosophila promotes systemic expression of antimicrobial peptides in response to microbial infection. We now demonstrate that the epidermal cells underlying the cuticle of larvae respond to infected wounds by local expression of the genes for the antimicrobial peptide cecropin A. Thus, the Drosophila epidermis plays an active role in the innate defence against microorganisms. The immune deficiency (imd) gene was found to be a crucial component of the signal‐induced epidermal expression in both embryos and larvae. In contrast, melanization, which is part of the wound healing process, is not dependent on the imd gene, indicating that the signalling pathways promoting melanization and antimicrobial peptide gene expression can be uncoupled.
Converting MlyI endonuclease into a nicking enzyme by changing its oligomerization state
Authors: Besnier Caroline E , Kong Huimin
Published: July 2002

N.BstNBI is a nicking endonuclease that recognizes the sequence GAGTC and nicks one DNA strand specifically. The Type IIs endonuclease, MlyI, also recognizes GAGTC, but cleaves both DNA strands. Sequence comparisons revealed significant similarities between N.BstNBI and MlyI. Previous studies showed that MlyI dimerizes in the presence of a cognate DNA, whereas N.BstNBI remains a monomer. This suggests that dimerization may be required for double‐stranded cleavage. To test this hypothesis, we used a multiple alignment to design mutations to disrupt the dimerization function of MlyI. When Tyr491 and Lys494 were both changed to alanine, the mutated endonuclease, N.MlyI, no longer formed a dimer and cleaved only one DNA strand specifically. Thus, we have shown that changing the oligomerization state of an enzyme changes its enzymatic function. This experiment also established a protocol that could be applied to other Type IIs endonucleases in order to generate more novel nicking endonucleases.
Directional encoding by fish auditory systems
Authors: Fay Richard R. , Edds–Walton Peggy L.
Published: July 2002

This paper reviews and discusses several investigations of the peripheral neural code for the directional axis of acoustical particle motion in the saccule of two fishes: goldfish (
Carassius auratus
) and toadfish (
Opsanus tau
). Most saccular afferents are directional in the manner of hair cells, having a cosine–shaped directional response pattern. The saccular sensory epithelia are orientated almost vertically in a parasagittal plane. In the horizontal plane, these epithelia are orientated obliquely with respect to the midline. Hair–cell stereocilia project perpendicularly. Thus, directional response patterns of saccular afferents tend to be orientated in azimuth parallel to the orientation of the epithelia in the head. The oblique angle of the toadfish saccule is greater than that of the goldfish, and the range of best directions in the horizontal plane for each species reflects those differing orientations. The azimuth of acoustical particle motion could be computed by comparing the relative activation of the two saccules, as is the case for the ears of most terrestrial vertebrates. The spatial patterns of saccular hair–cell orientation of most fishes thus appear to have little function in azimuthal source location, but for toadfish are probably most important for determining the elevation of monopole sources.
Recommendations of the American Association of Physicists in Medicine on interstitial source calibration and dosimetry: Implications for dose specification and prescription
Authors: Williamson Jeffrey F. , Coursey Bert M. , DeWerd Larry A. , Hanson William F. , Nath Ravinder , Rivard Mark J. , Ibbott Geoffrey
Published: July 2002

The National Institute of Standards and Technology (NIST) introduced a national standard for air kerma strength of the ThreaSeed® Model 200 source (the only seed available until 1999) in early 1999. Correct implementation of the NIST‐99 standard requires the use of dose rate constants normalized to this same standard. Prior to the availability of this standard, the vendor's calibration procedure consisted of intercomparing Model 200 seeds with a source with a NIST‐traceable activity calibration. The AAPM undertook a comprehensive review of source dosimetry including (i) comparison of the vendor and NIST‐99 calibration standards; (ii) comparison of original Task Group 43 dosimetry parameters with more recent studies; (iii) evaluation of the vendor's calibration history; and (iv) evaluation of administered‐to‐prescribed dose ratios from the introduction of sources in 1987 to the present. This review indicates that for a prescribed dose of 115 Gy, the administered doses were (a) 124 Gy for the period 1988–1997 and (b) 135 Gy for the period 1997–1999. The AAPM recommends that the following three steps should be undertaken concurrently to implement correctly the 1999 dosimetry data and NIST‐99 standard for source: (1) the vendor should provide calibrations in terms of air kerma strength traceable to NIST‐99 standard, (2) the medical physicist should update the treatment planning system with properly normalized (to NIST‐99) dosimetry parameters for the selected source model, and (3) the radiation oncologist in collaboration with the medical physicist should decide which clinical experience they wish to duplicate; the one prior to 1997 or the one from 1997 to 1999. If the intent is to duplicate the experience prior to 1997, which is backed by the long‐term follow‐up and published outcome studies, then the prior prescriptions of 115 Gy should be replaced by 124 Gy to duplicate that experience.
Frication noise modulated by voicing, as revealed by pitch-scaled decomposition
Authors: Jackson Philip J. B. , Shadle Christine H.
Published: July 2002

A decomposition algorithm that uses a pitch-scaled harmonic filter was evaluated using synthetic signals and applied to mixed-source speech, spoken by three subjects, to separate the voiced and unvoiced parts. Pulsing of the noise component was observed in voiced frication, which was analyzed by complex demodulation of the signal envelope. The timing of the pulsation, represented by the phase of the anharmonic modulation coefficient, showed a step change during a vowel-fricative transition corresponding to the change in location of the noise source within the vocal tract. Analysis of fricatives /β, v, ð, z, ȝ, v̥, ʕ/ demonstrated a relationship between steady-state phase and place, and f0 glides confirmed that the main cause was a place-dependent delay.
Binaural processing model based on contralateral inhibition. III. Dependence on temporal parameters
Authors: Breebaart Jeroen , van de Par Steven , Kohlrausch Armin
Published: July 2002

This paper and two accompanying papers [Breebaart et al., J. Acoust. Soc. Am. 110, 1074–1088 (2001); 110, 1089–1104 (2001)] describe a computational model for the signal processing of the binaural auditory system. The model consists of several stages of monaural and binaural preprocessing combined with an optimal detector. Simulations of binaural masking experiments were performed as a function of temporal stimulus parameters and compared to psychophysical data adapted from literature. For this purpose, the model was used as an artificial observer in a three-interval, forced-choice procedure. All model parameters were kept constant for all simulations. Model predictions were obtained as a function of the interaural correlation of a masking noise and as a function of both masker and signal duration. Furthermore, maskers with a time-varying interaural correlation were used. Predictions were also obtained for stimuli with time-varying interaural time or intensity differences. Finally, binaural forward-masking conditions were simulated. The results show that the combination of a temporal integrator followed by an optimal detector in the time domain can account for all conditions that were tested, except for those using periodically varying interaural time differences (ITDs) and those measuring interaural correlation just-noticeable differences (jnd’s) as a function of bandwidth.
Transient acoustic wave fields in continuously layered media with depth-dependent attenuation: An analysis based on higher-order asymptotics
Authors: Verweij Martin D.
Published: July 2002

A method is presented for the analysis of the space-time domain acoustic wave field in a continuously layered, lossy, isotropic fluid or equivalent fluid. Application of vertically varying compliance and inertia memory functions enables the modeling of a large class of depth-dependent loss properties. The method is based on integral transformations and consists of three steps. First, a temporal Laplace transformation with a real and positive transform parameter is applied, which is followed by horizontal spatial Fourier transformations. Second, higher-order, WKBJ-like asymptotic representations are derived that form approximate solutions of the resulting transform domain problem. With the chosen forward transformation process, problems caused by a zero vertical slowness are avoided, and the need for more intricate types of asymptotics is absent. Third, the Cagniard–De Hoop method is employed for the transformation back to the space-time domain. The form of the transform domain expressions allows for a very efficient use of the inversion process, while many steps of the inverse transformation may be performed analytically. Since the method does not impose a numerical limit on the bandwidth of the result, it may also be employed to generate a Green’s function. Numerical results are presented for reflections from half-spaces filled with a continuously layered, equivalent fluid with depth-dependent losses. At each level these losses show an almost “constant-Q” behavior in the frequency domain. The results show that there is an interval, beginning with the arrival time, on which the improvement due to the use of higher-order asymptotics is significant.
Piano strings and “phantom” partials
Authors: Conklin Harold A.
Published: July 2002

Additional partials can occur in the radiated tone of pianos at frequencies other than those predicted by classical string equations.
A0
and A1 coupling, arching, rib height, and f-hole geometry dependence in the 2 degree-of-freedom network model of violin cavity modes
Authors: Bissinger George
Published: July 2002

Six free parameters in the 2 degree-of-freedom (2DOF) network model [E. A. G. Shaw, J. Acoust. Soc. Am. 87, 398–410 (1990)] for the A0 and A1 cavity modes of the violin were optimized by fitting a 64-measurement database of frequencies and upper-/lower-bout pressure ratios obtained by varying volumes of water in a rigid, zero-arch aluminum violin cavity surrogate with various orientations. The optimized 2DOF model predicts an A0 frequency dependence on cavity volume of f∼V−0.25, quite different from the Helmholtz value of V−0.50 but in excellent agreement with experiment, signaling substantial coupling between the A0 and A1 modes. After modifying the model to separate rib height and arching dependence, predicted frequencies and pressure ratios behaved similarly—all decreased with increasing rib height or arching—with the notable exception of A1 frequencies, which increased with arching. For 11 instruments ranging in size from a 1/16th size violin to violoncellos, the optimized 2DOF model predicted A0 frequencies consistently ∼11% higher than experiment; similarly A1 frequency predictions were 15% high. The effects of sliding, flipping or rotating the f-holes were also investigated.
Steerable adaptive first- and second-order differential microphones
Authors: Elko Gary W.
Published: July 2002

Directional microphone arrays are spatial filters that can be designed to improve the sound quality of speech in audio telecommunication by removing acoustic signals arriving from undesired directions. Recently, there has been a large interest in adaptive microphone systems (also sometimes referred to as ‘‘smart microphones’’), since these systems automatically self-adjust their spatial response to minimize acoustic interference and thereby increase the desired signal-to-noise ratio. The talk will present adaptive first- and second-order differential microphone arrays that have fixed look directions dependent on the array geometry. A generalized version of the adaptive first-order system will then be presented where the look direction can be arbitrarily oriented (independent of the array spatial orientation). The commensurate problem of acoustic echo cancellation with adaptive microphones will also be discussed and some potential solutions given.
Direct numerical simulation of sound generation in turbulent shear flows
Authors: Colonius Tim
Published: July 2002

Direct numerical simulations of turbulent shear flows and their radiated acoustic fields have provided new insights into the mechanisms of sound generation, as well as the efficacy and limitations of the acoustic analogy approach. At present, these computations are expensive, and limited to relatively low Reynolds number and canonical flows. The computational approach consists of using high-order accurate numerical methods, together with accurate and robust nonreflecting and buffer-zone boundary conditions. This talk will focus on the results of computations of sound generated in mixing layers, jets, and open cavity flows. The relationship between linear stability waves in the flow and the radiated acoustic field is examined, in the context of a forced subsonic mixing layer and a fully turbulent supersonic round jet. For the subsonic flow, the acoustic sources can be modeled as wave packets, which radiate a superdirective acoustic field. For the supersonic jet, the directly computed (i.e., nonlinear source) acoustic field is compared to predictions based on radiating stability waves. Finally, the flow/acoustic instabilities in the subsonic flow over an open cavity are examined, and control strategies for reducing the internal acoustic load are explored. [Work supported by NSF (CTS-9501349) and AFOSR (F49620-98-1-0095).]
State and trends of acoustics education in Germany
Authors: Költzsch Peter
Published: July 2002

An overall view of the state of the education in the field of acoustics in Germany, Austria, and Switzerland is given in ‘‘Guide to Acoustics Studies’’ (2nd ed., July 1998, edited by DEGA). In Germany, acoustics is taught at 63 institutes (23 universities, 16 universities of technology, and 3 universities for music, art film, or television). In connection with education, the following problem is of great interest: How is the discipline of acoustics integrated into the traditional faculties of German universities? The present state is: integration of acoustics in mechanical, electrical, environmental engineering et al. On the other hand, a characteristic problem also is the existence of a ‘‘strong’’ acoustics institute at a university with a considerable research and education potential and, on the other hand, smaller special acoustics research and education capacities in all those scientific disciplines in which acoustics plays an important role. Here the question emerges whether it is more expedient for the development of acoustics to ‘‘keep’’ so-called ‘‘acoustics pets’’ in several faculties or to found a central acoustics institute to satisfy all requirements at the institutes and at the university in all. However, into which faculty should this ‘‘acoustics institute’’ be integrated then?
Novel acoustic sources from squeezed cavities in car tires
Authors: Gagen M. J.
Published: July 2002

This paper demonstrates that the partial squeezing of car tire cavities at ground impact cannot be adequately modeled by the usual acoustic wave equation. A more complete treatment must begin with the Euler equations for fluid flow in a squeezed cavity to derive a wave equation dependent on cavity wall velocities and accelerations. These can be sizable as ground impact causes the walls of a tire cavity to move with velocities of order 1 m/s and with accelerations of 103 m/s2 over time scales of about 1 ms. Further, the geometry of a typical cavity is such that width compression causes significant increases in pressure and density to occur before the arrival of the rarefaction wave propagating from the open end of the cavity begins to exhaust the full length of the cavity. This causes significant departures from equilibrium density and pressure conditions. These influences are demonstrated both analytically and numerically.
Mechanisms for subcritical penetration into a sandy bottom: Experimental and modeling results
Authors: Maguer Alain , Fox Warren L. J. , Schmidt Henrik , Pouliquen Eric , Bovio Edoardo
Published: July 2002

This paper presents preliminary results of a recent study whose overall objectives are to determine the mechanisms contributing significantly to subcritical acoustic penetration into ocean sediments, and to quantify the results for use in sonar performance prediction for the detection of buried objects. In situ acoustic measurements were performed on a sandy bottom whose geoacoustical and geomorphological properties were also measured. A parametric array mounted on a tower moving on a rail was used to insonify hydrophones located above and below the sediment interface. Data covering grazing angles both above and below the nominal critical angle and in the frequency range 2–15 kHz were acquired and processed. The results are compared to two models that account for scattering of sound at the rough water–sediment interface into the sediment. Although all possible mechanisms for subcritical penetration are not modeled, the levels predicted by both models are consistent with the levels observed in the experimental data. For the specific seafloor and experimental conditions examined, the analysis suggests that for frequencies below 5–7 kHz sound penetration into the sediment at subcritical insonification is dominated by the evanescent field, while scattering due to surface roughness is the dominant mechanism at higher frequencies.
Determination of the dynamic elastic moduli and internal friction using thin resonant bars
Authors: Guo Qiushuang , Brown David A.
Published: July 2002

Analysis of the data from the resonant-bar technique for determining wave speed and internal friction is presented. Internal friction has been included in the longitudinal and torsional wave equations and the analytical solution has been obtained. In determining the acoustical constants of lossy materials, a broad frequency spectrum is used that includes many resonances and not just data at or near the individual resonances. Corrections due to the mass, length, stiffness, and damping of the transducers are also presented. The theoretical solutions are compared with the measured magnitude and phase response data for torsional, longitudinal, and flexural measurements and are shown to be in good agreement.
Internal viscosity dumbbell model with a Gaussian approximation
Authors: Schieber Jay D.
Published: July 2002

A noninertial Hookean dumbbell with internal viscosity (or internal friction) is studied in transient and steady shear flows by use of a Gaussian closure on the second moment equation of the configuration of the dumbbell. The model predicts shear thinning for the viscosity and first normal stress coefficients for all values of the relative internal viscosity parameter ε. A second Newtonian region is observed for the viscosity. Qualitative, but not quantitative, agreement is found with optically determined orientation angles of polymer coils in steady shear flows for dilute polymer solutions. The model greatly overestimates the amount of relative stretching of the polymer coil in steady shear flow. In startup flows, large, but finite, values of ε show shear stress overshoot at high shear rates, and oscillatory behavior at the highest shear rates studied. Transient negative values of the first normal stress difference are also predicted. The maximum in stress is attained at much lower values of strain than for the predictions at small ε. The oscillations are shown to be caused primarily by oscillations in the orientation of the polymer coil, rather than by oscillations in the size of the polymer coil. Instantaneous jumps in the shear stress at t=0 are observed in agreement with Manke and Williams. Cessation of shear flows shows a jump in stress in agreement with data on xanthan gum. The decay upon cessation is nonexponential, but does follow the Lodge–Meissner relation. The width of the polymer coil is predicted to go through a maximum during this decay. Also, the addition of internal viscosity to the dumbbell satisfactorally gives a positive asymptotic value for η′−ηs (in-phase complex viscosity minus solvent contribution) in small amplitude oscillatory shear flow.
Vanishing elasticity for wet foams: Equivalence with emulsions and role of polydispersity
Authors: Saint-Jalmes A. , Durian D. J.
Published: July 2002

We present an experimental study of the rheology of polydisperse aqueous foams of different gas volume fractions φ. With oscillatory deformation at fixed frequency, we determine the behavior of the maximum stress as a function of the strain amplitude. At low strain, the maximum stress increases linearly, defining a shear modulus G. At progressively higher strains, the response eventually becomes nonlinear, defining the yield strain and the yield stress. While φ decreases toward φc=0.635±0.01, G goes to zero, and the yield stress decreases by many orders of magnitude with a quadratic behavior. The yield strain, which can be extrapolated to 0.18±0.02 at φ=1, has a minimum value of 0.045±0.010 at φc. This behavior shows the occurrence of a melting transition located at φc, which can be correlated to the random close packing of spheres. We compare these results to similar ones obtained previously for monodisperse and polydisperse emulsions. Our new experiments clarify the rheological similarities between emulsions and foams, as well as the role of polydispersity. We find that as long as polydispersity is moderate, it does not play a crucial role in the elastic response of foams and emulsions.
Improved powder X-ray data for cancrinites IV: Franzinite
Authors: Ballirano Paolo , Maras Adriana
Published: July 2002

Improved powder X-ray diffraction (XRD) data for franzinite, the ten-layer member of the cancrinite group of minerals, were obtained using an automated parallel-beam powder diffractometer with a capillary mount. The cell parameters of franzinite were found to be a=12.8976(3) Å, c=26.5040(8) Å, V=3818.2(2) Å3 in space group P321, while the strongest reflections were at 3.725(100), 3.809(65), 3.562(56), 3.586(55), 2.662(42), 2.150(31) and 3.302(30) Å. The new results include an increased number of indexed peaks, improved figures-of-merit with respect to PDF 30-1170 and intensities validated by Rietveld refinement.
Assessment of MRI image distortion based on 6 consecutive years of annual QAs and measurements on 14 MRI scanners used for radiation therapy
Authors: Lu Lanchun , Yang Xiangyu , Raterman Brian , Jiang Xia , Meineke Matthew , Grecula John , Blakaj Dukagjin , Palmer Joshua , Raval Raju , Thomas Evan , Hintenlang David , Gupta Nilendu
Published: November 2022

Purpose

To determine the magnitude of MRI image distortion based on 6 consecutive years of annual quality assurances/measurements on 14 MRI scanners used for radiation therapy and to provide evidence for the inclusion of additional margin for treatment planning.

Methods and materials

We used commercial MRI image phantoms to quantitatively study the MRI image distortion over period of 6 years for up to 14 1.5 and 3 T MRI scanners that could potentially be used to provide MRI images for treatment planning. With the phantom images collected from 2016 to 2022, we investigated the MRI image distortion, the dependence of distortion on the distance from the imaging isocenter, and the possible causes of large distortion discovered.

Results

MRI image distortion increases with the distance from the imaging isocenter. For a region of interest (ROI) with a radius of 100 mm centered at the isocenter, the mean magnitude of distortion for all MRI scanners is , and the maximum distortion varies from depending on MRI scanners. For an ROI with a radius of 200 mm centered at the isocenter, the mean magnitude of distortion increases to , and the range of the maximum distortion increases to depending on MRI scanners. The distortion could reach 2 mm at 150 mm from the isocenter.

Conclusion

An additional margin to accommodate image distortion should be considered for treatment planning. Imaging with proper patient alignment to the isocenter is vital to reducing image distortion. We recommend performing image distortion checks annually and after major upgrade on MRI scanners.
Acoustic Properties of Aerogels: Current Status and Prospects
Authors: Budtova Tatiana , Lokki Tapio , Malakooti Sadeq , Rege Ameya , Lu Hongbing , Milow Barbara , Vapaavuori Jaana , Vivod Stephanie L.
Published: November 2022

Noise reduction remains an important priority in the modern society, in particular, for urban areas and highly populated cities. Insulation of buildings and transport systems such as cars, trains, and airplanes has accelerated the need to develop advanced materials. Various porous materials, such as commercially available foams and granular and fibrous materials, are commonly used for sound mitigating applications. In this review, a special class of advanced porous materials, aerogels, is examined, and an overview of the current experimental and theoretical status of their acoustic properties is provided. Aerogels can be composed of inorganic matter, synthetic or natural polymers, as well as organic/inorganic composites and hybrids. Aerogels are highly porous nanostructured materials with a large number of meso‐ and small macropores; the mechanisms of sound absorption partly differ from those of traditional porous absorbers possessing large macropores. The understanding of the acoustic properties of aerogels is far from being complete, and experimental results remain scattered. It is demonstrated that the structure of the aerogel provides a complex three‐dimensional architecture ideally suited for promising high‐performance materials for acoustic mitigation systems. This is in addition to the numerous other desirable properties that include low density, low thermal conductivity, and low refractive index.
Ballistic Thermal Transport at Sub‐10 nm Laser‐Induced Hot Spots in GaN Crystal
Authors: Huang Dezhao , Sun Qiangsheng , Liu Zeyu , Xu Shen , Yang Ronggui , Yue Yanan
Published: November 2022

Ballistic thermal transport at nanoscale hotspots will greatly reduce the performance of a Gallium nitride (GaN) device when its characteristic length reaches the nanometer scale. In this work, the authors develop a tip‐enhanced Raman thermometry approach to study ballistic thermal transport within the range of 10 nm in GaN, simultaneously achieving laser heating and measuring the local temperature. The Raman results show that the temperature increase from an Au‐coated tip‐focused hotspot up to two times higher (40 K) than that in a bare tip‐focused region (20 K). To further investigate the possible mechanisms behind this temperature difference, the authors perform electromagnetic simulations to generate a highly focused heating field, and observe a highly localized optical penetration, within a range of 10 nm. The phonon mean free path (MFP) of the GaN substrate can thus be determined by comparing the numerical simulation results with the experimentally measured temperature increase which is in good agreement with the average MFP weighted by the mode‐specific thermal conductivity, as calculated from first‐principles simulations. The results demonstrate that the phonon MFP of a material can be rapidly predicted through a combination of experiments and simulations, which can find wide application in the thermal management of GaN‐based electronics.
Replacing the oxidation‐sensitive triaminoaryl chemotype of problematic KV7 channel openers: Exploration of a nicotinamide scaffold
Authors: Wurm Konrad W. , Bartz Frieda‐Marie , Schulig Lukas , Bodtke Anja , Bednarski Patrick J. , Link Andreas
Published: November 2022

KV7 channel openers have proven their therapeutic value in the treatment of pain as well as epilepsy and, moreover, they hold the potential to expand into additional indications with unmet medical needs. However, the clinically validated but meanwhile discontinued KV7 channel openers flupirtine and retigabine bear an oxidation‐sensitive triaminoraryl scaffold, which is suspected of causing adverse drug reactions via the formation of quinoid oxidation products. Here, we report the design and synthesis of nicotinamide analogs and related compounds that remediate the liability in the chemical structure of flupirtine and retigabine. Optimization of a nicotinamide lead structure yielded analogs with excellent KV7.2/3 opening activity, as evidenced by EC50 values approaching the single‐digit nanomolar range. On the other hand, weighted KV7.2/3 opening activity data including inactive compounds allowed for the establishment of structure–activity relationships and a plausible binding mode hypothesis verified by docking and molecular dynamics simulations.
Novel staging for gastric neuroendocrine neoplasms by incorporating the WHO grading into the TNM staging system
Authors: Zhang Rihong , Guo Yu , Wang Youliang , Hu Li , Fang Cheng , Yang Yujie , Yang Xianqi , Chen Luohai , Chen Jie , Wang Wei , Sun Xiaowei
Published: November 2022

Background

The 8th tumor‐node‐metastasis (TNM) classification of the American Joint Committee on Cancer (AJCC) can be used to estimate the prognosis of gastric neuroendocrine tumor (gNET) and gastric neuroendocrine carcinoma (gNEC) patients but not gastric neuroendocrine neoplasms (gNENs).

Methods

First, in the SEER (training) dataset, a TNMG system was built by combining the WHO G grade (G1‐4; NEC grouped into G4) with the 8th AJCC T (T1‐4), N (N0‐1), and M (M0‐1) stage, which was then validated in a Chinese (validation) cohort.

Results

In all, 2245 gNENs cases from the training dataset and 280 cases from the validation dataset were eligible. The T stage, M stage, and G grade were independent prognostic factors for OS in both datasets (all p < 0.05). The TNMG staging system demonstrated better C‐index for predicting OS than the 8th AJCC TNM staging system in both the training (0.87, 95%CI: 0.86–0.88 vs. 0.79, 95%CI: 0.77–0.81) and validation (0.77, 95%CI: 0.73–0.80 vs. 0.75, 95%CI: 0.71–0.79) datasets. The AUC of the 3‐year OS for the TNMG staging system was 0.936 and 0.817 in the SEER and validation dataset, respectively; higher than those of the 8th AJCC system (vs. 0.843 and 0.779, respectively). DCA revealed that compared with the 8th AJCC TNM staging system, the TNMG staging system demonstrated superior net prognostic benefit in both the training and validation datasets.

Conclusions

The proposed TNMG staging system could more accurately predict the 3‐ and 5‐year OS rate of gNENs patients than the 8th AJCC TNM staging system.
Alternative splicing of HSPA12A pre‐RNA by SRSF11 contributes to metastasis potential of colorectal cancer
Authors: Pan Yao‐Jie , Huo Fu‐Chun , Kang Meng‐Jie , Liu Bo‐Wen , Wu Meng‐Di , Pei Dong‐Sheng
Published: November 2022

Background

Dysregulation of alternative splicing (AS) induced by serine/arginine‐rich proteins has recently been linked to cancer metastasis. Nonetheless, as a member of the serine/arginine‐rich protein family, the involvement of SRSF11 in colorectal cancer (CRC) is unknown.

Methods

The TCGA dataset and clinical samples were used to assess SRSF11 expression levels in CRC. For SRSF11, functional experiments were conducted both in vitro and in vivo. RNA‐seq technology was used to analyze and screen SRSF11‐triggered AS events, which were then confirmed by in vivo UV crosslinking and immunoprecipitation (CLIP) and mini‐gene reporter assays. Jalview software was used to determine the preferential binding motif with relation to exon skipping (ES) events. Furthermore, coimmunoprecipitation (Co‐IP) and Phospho‐tag SDS‐PAGE experiments were used to investigate PAK5‐mediated phosphorylation regulation on SRSF11, and in vitro kinase experiments validated the interaction.

Results

In CRC, SRSF11 was discovered to be overexpressed and associated with a poor prognosis. And SRSF11 played a pro‐metastatic role in vitro and in vivo. By screening SRSF11‐regulated AS events, we identified the binding motif of SRSF11‐triggered splicing‐switching of HSPA12A AS, which specifically regulated HSPA12A AS by directly binding to a motif in exon 2. Mechanistically, the HSPA12A transcript with exon 2 retention increased N‐cadherin expression by promoting RNA stability. Furthermore, the oncogenic kinase PAK5 phosphorylated SRSF11 at serine 287, protecting it from ubiquitination degradation.

Conclusions

SRSF11 exerts pro‐metastatic effects in CRC by inhibiting the AS of HSPA12A pre‐RNA. Our findings point to SRSF11‐regulated HSPA12A splicing as a novel relationship between SRSF11‐regulated splicing and CRC metastasis and suggest a PAK5/SRSF11/HSPA12A axis as a potential therapeutic target and prognostic biomarker in CRC.
Extensive sensorimotor training enhances nociceptive cortical responses in healthy individuals
Authors: Zamorano Anna M. , Kleber Boris , Arguissain Federico , Vuust Peter , Flor Herta , Graven‐Nielsen Thomas
Published: November 2022

Background

Prolonged and repeated sensorimotor training is a crucial driver for promoting use‐dependent plasticity, but also a main risk factor for developing musculoskeletal pain syndromes, yet the neural underpinnings that link repetitive movements to abnormal pain processing are unknown.

Methods

Twenty healthy musicians, one of the best in vivo models to study use‐dependent plasticity, and 20 healthy non‐musicians were recruited. Perceptual thresholds, reaction times (RTs) and event‐related potentials (ERPs) were recorded using nociceptive intra‐epidermal and non‐nociceptive transcutaneous electrical stimulation.

Results

In response to comparable stimulus intensities, musicians compared to non‐musicians showed larger non‐nociceptive N140 (associated with higher activation of regions within the salience network), higher nociceptive N200 ERPs (associated with higher activation of regions within the sensorimotor network) and faster RTs to both stimuli. Non‐musicians showed larger non‐nociceptive P200 ERP. Notably, a similar P200 component prominently emerged during nociceptive stimulation in non‐musicians. Across participants, larger N140 and N200 ERPs were associated with RTs, whereas the amount of daily practice in musicians explained non‐nociceptive P200 and nociceptive P300 ERPs.

Conclusions

These novel findings indicate that the mechanisms by which extensive sensorimotor training promotes use‐dependent plasticity in multisensory neural structures may also shape the neural signatures of nociceptive processing in healthy individuals.

Significance

Repetitive sensorimotor training may increase the responsiveness of nociceptive evoked potentials. These novel data highlight the importance of repetitive sensorimotor practice as a contributing factor to the interindividual variability of nociceptive‐related potentials.
A multi‐proxy study of Umbric Ferralsols genesis in a high‐mountain environment in Rio de Janeiro state
Authors: Pereira Marcos Gervasio , da Silva Rafael Cipriano , Pinheiro Junior Carlos Roberto , da Silva Neto Eduardo Carvalho , Fontana Ademir , Schiavo Jolimar Antonio , Carvalho Maranhão Deyvid Diego , de Azevedo Antônio Carlos , Pacheco Anderson Almeida
Published: November 2022

The formation of strongly weathered soils of the tropics (Ferralsols) with high carbon stocks (thick A‐horizon/umbric horizon) is still not understood. In order to contribute to the understanding of the formation of Umbric Ferralsols, we studied these soils in the highlands of Rio de Janeiro state (Brazil) from various perspectives. We analysed soil morphology, micromorphology, physical and chemical soil attributes, soil phytolith assemblages, and δ13C isotopic composition in a multi‐proxy study. The profiles presented ferralic horizons with SiO2/Al2O3 ratio (ki index) < 1.0, low silt/clay ratio values, predominance of kaolinite and presence of gibbsite, and low cation exchange capacity. These characteristics indicate a high degree of weathering and ferralitization. The isotopic and phytolithic variations indicate climatic modifications during the Late Holocene (approximately 2300 years ago), with a predominance of mixed vegetation composed of plants of the C3 and C4 photosynthetic cycles. This condition favoured the accumulation of organic matter in the Umbric Ferralsols. The accumulation of organic matter in subsurface B horizons occurred under drier past climatic conditions in a savanna environment, which may have favoured the occurrence of fires, thereby explaining the charcoal fragments identified in the micromorphological analyses. In contrast, the development of the umbric horizon in the profiles was favoured under wetter environmental conditions than the present environmental conditions, and favoured the development of vegetation and intense accumulation of organic material on the surface and at depths close to 100 cm. The pedogenesis of umbric horizons in Ferralsols reinforces the importance of bioturbation in the incorporation of organic matter, intensifying the humification and resulting in a strong darkening of the soil (melanization).
Evaluation of rheological and optical properties plus stability of beverage cloud emulsions prepared with corn oil, gum rosin, and modified starch
Authors: Nasrolahi Soghra , Sadeghizadeh‐Yazdi Jalal , Ehrampoush Mohammad Hassan , Madadizadeh Farzan , Khalili Elham
Published: November 2022

Rheological and optical properties as well as stability of beverage cloud emulsion prepared with corn oil, gum rosin (EG), and modified starch were evaluated in model juices. The emulsions were prepared with three levels of modified starch (6%, 12%, and 18% w/w), corn oil (5%, 7%, and 9% w/w), and gum rosin (1%, 3%, and 5% w/w). Experiments were designed using the Box–Behnken design. The analysis of variance (ANOVA) was used to evaluate the significance of the experimental factors and the factors were then optimized using response surface methodology (RSM). The stability of emulsions was measured through ring formation in both the primary emulsion and the model beverage as a function of storage time. Also, the effect of heat treatment was examined on the stability of emulsions in model beverages. The results revealed that heat treatment did not cause the formation of an observable ring in the model juice containing stabilized starch emulsion. Rheological examinations of the stable emulsion samples showed a pseudoplastic and time‐independent non‐Newtonian behavior. The optimum emulsion sample consistency coefficient was 0.46 Pa.sn and the flow behavior index was 0.88. The apparent viscosity of the optimum emulsion sample based on Herschel–Bulkley model at shear rate of 100 s−1 was 0.0439 Pa.s. The results indicated that the concentration of modified starch, gum rosin, and corn oil has a significant effect on the stability and creaminess of the emulsion. In general, with an increase in the percentage of modified starch, the stability rises while the rate of creaminess decreases (p < 0.05). Furthermore, elevation of the concentration of corn oil had a significant effect on the opacity of emulsions and the final product (p < 0.05).
Petrogenesis of mantle peridotites in Neo‐Tethyan ophiolites from the Eastern Himalaya and Indo‐Myanmar Orogenic Belt in the geo‐tectonic framework of Southeast Asia
Authors: Singh Athokpam Krishnakanta , Chung Sun‐Lin , Somerville Ian D.
Published: November 2022

The Neo‐Tethyan ophiolites of the Tuting‐Tidding Suture Zone (TTSZ), Eastern Himalaya (viz., Tidding Ophiolite Complex and Mayodia Ophiolite Complex) and Indo‐Myanmar Orogenic Belt (IMOB, i.e., Nagaland Ophiolite Complex and Manipur Ophiolite Complex) which lie along the southern extension of the Indus‐Tsangpo Suture Zone have been collectively investigated through the mantle‐derived peridotite sequence. The peridotites (harzburgite and dunites) in the Eastern Himalaya ophiolites are refractory, constrained by the high Fo olivine content (~95), high Cr# [Cr/(Cr + Al)] (0.90–0.99), as well as by the parental melt composition of Cr‐spinels (Al2O3 melt = 3.05–7.55 wt%, FeO/MgO = 0.69–6.46). They have slightly “U‐shaped” chondrite‐normalized Rare Earth Elements (REE) patterns with slight enrichment in Light Rare Earth Elements (LREE) relative to the patterns expected for residues of partial melting, thereby indicating a reaction with the LREE‐enriched melt. These peridotites represent residual portions of a depleted/enriched mantle that underwent partial melting up to 23% in the nascent forearc of an intra‐oceanic subduction zone, and later metasomatized by high‐temperature silicate melts and low‐temperature hydrous fluids. They are composed of a very refractory olivine‐spinel assemblage (Fo: 91.68–96.44; Cr#: 0.90–0.99), corroborating a boninitic parentage, with influence from melt‐rock interactions. In the case of the IMOB ophiolites, a wide range of chemical compositions is observed in the mantle sequence. Lherzolites display low Cr# (0.12–0.26) and TiO2 (<0.11) associated with high Mg# [Mg/(Mg + Fet)] (0.69–0.76) in the Cr‐spinels present in them. They represent the residual product of a fertile mantle that underwent low‐degree partial melting (2%–10%) in a divergent mid‐ocean ridge (MOR) tectonic setting. On the other hand, the harzburgites and dunites of the IMOB have high Cr# (0.84–0.90) and low TiO2 (<0.06 wt%) Cr‐spinels and exhibit slightly U‐shaped REE distributions indicating their derivation from a highly depleted mantle source, which experienced higher degree partial melting (17%–24%) similar to those of supra‐subduction zone (SSZ) harzburgites and dunites of the TTSZ peridotites. The occurrence of both MOR and SSZ types of melting regimes indicates that the peridotites in the IMOB ophiolites formed at two major different stages of the pre‐subduction and subduction events, respectively. However, the peridotites of Eastern Himalaya ophiolites were formed only during subduction tectonics. Thus, we argue that the mantle peridotites in the ophiolites of northeast India evolved from lherzolite through clinopyroxene‐harzburgite and harzburgite then to highly refractory dunite, supporting multistage melting and melt‐rock reaction processes during their generation.