bluuebunny/crossref_metadata_2025 huggingface dataset:
Synapsins as regulators of neurotransmitter release
Authors: Hilfiker Sabine , Pieribone Vincent A. , Czernik Andrew J. , Kao Hung-Teh , Augustine George J. , Greengard Paul
Published: July 2002

One of the crucial issues in understanding neuronal transmission is to define the role(s) of the numerous proteins that are localized within presynaptic terminals and are thought to participate in the regulation of the synaptic vesicle life cycle. Synapsins are a multigene family of neuron–specific phosphoproteins and are the most abundant proteins on synaptic vesicles. Synapsins are able to interact
in vitro
with lipid and protein components of synaptic vesicles and with various cytoskeletal proteins, including actin. These and other studies have led to a model in which synapsins, by tethering synaptic vesicles to each other and to an actin–based cytoskeletal meshwork, maintain a reserve pool of vesicles in the vicinity of the active zone. Perturbation of synapsin function in a variety of preparations led to a selective disruption of this reserve pool and to an increase in synaptic depression, suggesting that the synapsin–dependent cluster of vesicles is required to sustain release of neurotransmitter in response to high levels of neuronal activity. In a recent study performed at the squid giant synapse, perturbation of synapsin function resulted in a selective disruption of the reserve pool of vesicles and in addition, led to an inhibition and slowing of the kinetics of neurotransmitter release, indicating a second role for synapsins downstream from vesicle docking. These data suggest that synapsins are involved in two distinct reactions which are crucial for exocytosis in presynaptic nerve terminals. This review describes our current understanding of the molecular mechanisms by which synapsins modulate synaptic transmission, while the increasingly well–documented role of the synapsins in synapse formation and stabilization lies beyond the scope of this review.
Concluding overview: looking back, looking forward
Authors: Rickinson Alan
Published: July 2002

The γ–herpesviruses are a group of related agents which share the same broad strategy for infection of and persistence within the lymphoid tissues of their hosts. Yet in evolutionary terms these agents are sufficiently diverse to display multiple different molecular mechanisms whereby that strategy can be achieved. Attempts are made to relate the different in vitro growth transforming capacities of the γ
1
–herpesviruses, the T–lymphotropic γ
2
–herpesviruses and the B–lymphotropic γ
2
–herpesviruses to what is known about the biology of these virus infections in their natural or in experimental hosts. The review then summarizes the evidence linking γ–herpesviruses with oncogenesis and proposes that the diverse spectrum of Epstein–Barr virus and human herpesvirus 8–associated human tumours falls into three pathogenetically distinct categories. Many questions remain unanswered in the areas of γ–herpesvirus biology and disease pathogenesis: resolving these questions will require a broadening of our experimental approaches and a willingness to relinquish ‘single–model’ panaceas.
High-Resolution BAC-Based Map of the Central Portion of Mouse Chromosome 5
Authors: Crabtree Jonathan , Wiltshire Tim , Brunk Brian , Zhao Shaying , Schug Jonathan , Stoeckert Christian J. , Bucan Maja
Published: July 2002

The current strategy for sequencing the mouse genome involves the combination of a whole-genome shotgun approach with clone-based sequencing. High-resolution physical maps will provide a foundation for assembling contiguous segments of sequence. We have established a bacterial artificial chromosome (BAC)-based map of a 5-Mb region on mouse Chromosome 5, encompassing three gene families: receptor tyrosine kinases (PdgfraKit-Kdr), nonreceptor protein-tyrosine type kinases (Tec–Txk), and type-A receptors for the neurotransmitter GABA (Gabra2, Gabrb1, Gabrg1, and Gabra4). The construction of a BAC contig was initiated by hybridization screening the C57BL/6J (RPCI-23) BAC library, using known genes and sequence tagged sites (STSs). Additional overlapping clones were identified by searching the database of available restriction fingerprints for the RPCI-23 and RPCI-24 libraries. This effort resulted in the selection of >600 BAC clones, 251 kb of BAC-end sequences, and the placement of 40 known and/or predicted genes within this 5-Mb region. We use this high-resolution map to illustrate the integration of the BAC fingerprint map with a radiation-hybrid map via assembled expressed sequence tags (ESTs). From annotation of three representative BAC clones we demonstrate that up to 98% of the draft sequence for each contig could be ordered and oriented using known genes, BAC ends, consensus sequences for transcript assemblies, and comparisons with orthologous human sequence. For functional studies, annotation of sequence fragments as they are assembled into 50–200-kb stretches will be remarkably valuable.
On the applicability of the AAPM TG‐60/TG‐43 dose calculation formalism to intravascular line sources: Proposal for an adapted formalism
Authors: Schaart Dennis R. , Clarijs Martijn C. , Bos Adrie J. J.
Published: July 2002

Despite the widely recognized usefulness of the AAPM TG‐43 brachytherapy dose calculation formalism, a straightforward application of this approach to describe the dose distribution about intravascular line sources as proposed by TG‐60 may be difficult or even impossible, especially when these line sources emit low‐energy photons or beta particles. The causes of these limitations are investigated and illustrated by means of some numerical examples. In order to solve the observed limitations an adapted formalism is proposed, intended specifically for the description of the dose rate distribution about line sources but conceptually similar to the TG‐43/TG‐60 formalism. Several examples are presented to illustrate the usefulness of the proposed line source dose calculation formalism.
Sector analysis of prostate implants
Authors: Bice William S. , Prestidge Bradley R. , Sarosdy Michael F.
Published: July 2002

The analysis of treatment plans generated following prostate implants (post plans) is an essential part of the patient's treatment regimen. The results are used to determine the adequacy of the individual implant and, just as importantly, to provide an evaluation of the institution's brachytherapy technique. Compiled post plan results can be used to compare data from different institutions and help determine guidelines that should be established as dosimetric goals. Sector analysis, or spatial dose mapping, is a novel method of analyzing brachytherapy results that has been developed for this purpose. The display of isodose curves provides spatial information pertaining to the dosimetric evaluation of post plans but is an unwieldy tool; ill suited to the creation of general conclusions for comparative efforts. Dose–volume histogram (DVH) analysis is an excellent tool for examining dosimetric results, but the spatial information is lost. Sector analysis bridges the gap between isodose curves and DVH analysis in post plan analysis. To perform sector analysis we divide the gland into three regions in the cranial–caudal direction (base, midgland, and apex) and four regions on each transverse slice (anterior, posterior, left and right). This gives twelve sectors, each identified by its location in the cranial–caudal direction and position on the transverse slice, e.g., posterior midgland. DVH analysis is performed for each region separately and compiled for display. We present an example of the use of this technique wherein we have analyzed a sequential series of 118 implants performed by a single practitioner (BRP) at two institutions over a calendar year. The implants were performed using two different techniques at the two institutions. Sector analysis was used to compare the results of the implants at the two institutions.
Dose to radiation therapists from activation at high‐energy accelerators used for conventional and intensity‐modulated radiation therapy
Authors: Rawlinson J. Alan , Islam Mohammad K. , Galbraith Duncan M.
Published: July 2002

The increased beam‐on times which characterize intensity‐modulated radiation therapy (IMRT) could lead to an increase in the dose received by radiation therapists due to induced activity. To examine this, gamma ray spectrometry was used to identify the major isotopes responsible for activation at a representative location in the treatment room of an 18 MV accelerator (Varian Clinac 21EX). These were found to be and The decay of the dose rate measured at this location following irradiation was analyzed in terms of the known half‐lives to yield saturation dose rates of 9.6, 12.4, and 6.2 μSv/h, respectively. A formalism was developed to estimate activation dose (μSv/week) due to successive patient irradiation cycles, characterized by the number of 18 MV fractions per week, F, the number of MU per fraction, M, the in‐room time between fractions, (min), and the treatment delivery time (min). The results are represented by the sum of two formulas, one for the dose from F M and one for the dose from the other isotopes For conventional therapy doses are about 60 μ Sv/week for an 18 MV workload of 60 000 MU/week. Irradiation for QA purposes can significantly increase the dose. For IMRT as currently practiced, lengthy treatment delivery times limit the number of fractions that can be delivered per week and hence limit the dose to values similar to those in conventional therapy. However for an IMRT regime designed to maximize patient throughput, doses up to 330 μSv/week could be expected. To reduce dose it is recommended that IMRT treatments should be delivered at energies lower than 18 MV, that in multienergy IMRT, high‐energy treatments should be scheduled in the latter part of the day, and that equipment manufacturers should strive to minimize activation in the design of high‐energy accelerators.
Suitability of laser stimulated TLD arrays as patient dose monitors in high dose x‐ray imaging
Authors: Geise R. A. , Schueler B. A. , Lien W. , Jones S. C.
Published: July 2002

Skin entrance doses of patients undergoing interventional x‐ray procedures are capable of causing skin damage and should be monitored routinely. Single TLD chips are not suitable because the location of maximum skin exposure cannot be predicted. Most photographic films are too sensitive at diagnostic x‐ray energies for dosimetry, exhibit temporal changes in response, and require special packaging by the user. We have investigated the suitability of laser heated TLDs in a polyimide binder in the range of 0.2–20 Gy. These are available in radioluscent arrays up to 30×30 cm for direct measurement of patient skin dose. Dose response was compared with a calibrated ion chamber dosimeter. Exposures were made at 60, 90, and 120 kVp, at low (fluoroscopy) and high (DSA) dose rates, and at different beam incidence angles. Longitudinal reproducibility and response to temperature changes during exposure were also checked. The dose response is linear below approximately 6 Gy where the slope starts to increase 2% per Gy. Errors were less than ±2% over a 0–80 degree range of beam incidence angles; less than ±3% for both dose rate variations and kVp differences between 70 and 120 kVp. The response was unaffected by temperature changes between 20 and 37 °C. Reproducibility is currently ±7%. TLD arrays are suitable for patient dosimetry in high dose fluoroscopy procedures if appropriate calibrations are used. Uncertainty in skin dose measurement is less than 10%, which is substantially better than film dosimetry.
Clinical implementation of a two‐component x‐ray source model for calculation of head‐scatter factors
Authors: Jursinic Paul A.
Published: July 2002

A calculation method is described, which presumes that linac output has two components. One component is direct x rays from the target and the remaining component is an extra‐focal, distributed source of radiation that is scattered from the flattening filter, primary collimator, and the jaws of the moveable collimator. This calculation method gives values for output factors that differ from measured values by no more than 0.5% for field widths from 4 to 40 cm, rectangular fields with long to short axis ratios as great as 10, symmetric and asymmetric fields, and source‐to‐axis distances from 65 to 360 cm. While this calculation method has great accuracy and flexibility, a minimal amount of input data is required: (1) measured output factors at a source‐to‐axis distance of 100 cm for square fields; (2) positions of the collimator with respect to the x‐ray source target; and (3) output factors measured at various source‐to‐axis distances for a field.
Fast image reconstruction for optical absorption tomography in media with radially symmetric boundaries
Authors: Hampel Uwe , Freyer Richard
Published: July 2002

In this paper we present a reconstruction algorithm to invert the linearized problem in optical absorption tomography for objects with radially symmetric boundaries. This is a relevant geometry for functional volume imaging of body regions that are sensitive to ionizing radiation, e.g., breast and testis. From the principles of diffuse light propagation in scattering media we derive the governing integral equations describing the effects of absorption variations on changes in the measurement data. Expansion of these equations into a Neumann series and truncation of higher‐order terms yields the linearized forward imaging operator. For the proposed geometry we utilize an invariance property of this operator, which greatly reduces the problem dimensionality. This allows us to compute the inverse by singular value decomposition and consequently to apply regularization techniques based on the knowledge of the singular value spectrum. The inversion algorithm is highly efficient computing slice images as fast as convolution‐backprojection algorithms in computed tomography (CT). To demonstrate the capacity of the inversion scheme we present reconstruction results for synthetic and phantom measurement data.
A doorless entry system for high‐energy radiation therapy rooms
Authors: Dawson D. J. , Wissing W. W. F. M. , Tonks R. E.
Published: July 2002

A doorless entry system has been designed for use in high‐energy radiation therapy rooms. The doorless entry improves patient access, safety and throughput, increases the physical safety for the radiation therapists, and avoids the significant cost of heavy shielding doors. The design meets concerns relating to radiation safety, operational ease, and authorized entry. The new system is currently operating in one room housing a cobalt‐60 unit and is to be employed in five additional rooms housing dual‐energy accelerators (maximum energies of 10 and 18 MV). The doorless entry has received wide approval from the radiation therapists and no concerns have been expressed with respect to unauthorized entry or radiation safety.
Dosimetry and treatment planning for boron neutron capture therapy
Authors: Raaijmakers C. P. J.
Published: July 2002

Dosimetric techniques were developed for the determination of the various dose components in phantoms irradiated with an epithermal neutron beam for boron neutron capture therapy (BNCT). Using paired ionization chambers and activation foils, the accuracy (1 standard deviation, SD) in the determination of the absolute thermal neutron fluence, gamma‐ray dose and fast neutron dose amounted to 5%, 5%, and 18%, respectively. Methods were developed which assure an agreement between prescribed and actual obtained values of 1% (1 SD) for the absolute beam output and 5%–10% (1 SD) for the blood–boron concentration during irradiation. Clinical dosimetry studies were performed resulting in a set of reference beam data which are used for quality control, dosimetry intercomparisons and as input for a conventional semi‐empirical treatment planning system (TPS). Using these reference beam data and the electron and photon beam model of the TPS, the various dose components could be calculated fast and with a high accuracy in a homogeneous anthropomorphic head phantom. At the central axis, the agreement between measurements and calculations was within 2%–3% (1 SD). It is concluded that the accuracy in dosimetry, beam output monitoring, blood–boron monitoring and treatment planning is sufficient to start clinical studies of BNCT in Petten, The Netherlands.
Mass energy‐absorption coefficients and mass collision stopping powers for electrons in tumors of various histologies
Authors: Maughan Richard L. , Chuba Paul , Porter Arthur T. , Ben‐Josef Edgar , Lucas David R. , Bjarngard Bengt E.
Published: July 2002

The mass energy‐absorption coefficients and electron mass collision stopping powers have been calculated for tumors of various histologies. Eleven excised or biopsied tumor specimens were considered, including samples from two squamous cell lung carcinomas, two sarcomas, three adenoid cystic carcinomas, two melanomas and two rectal carcinomas. The hydrogen, carbon, nitrogen and oxygen composition of the tumor samples was determined. Photon mass energy‐absorption data in the energy range 1 keV to 20 MeV have been calculated using elemental mass energy‐absorption coefficients previously calculated by Hubbell and Seltzer. Electron mass collision stopping powers for energies between 10 keV and 60 MeV were calculated from the values for water using the data and methodology described in ICRU Report #37. The ratio of the average mass energy‐absorption coefficient of the tumor samples to the coefficient of water was found to be 0.99 across most of the energies of clinical interest (>100 keV) except for photon energies of 5 MeV and above for which the ratio dropped to 0.98. The ratio of the average electron mass collision stopping power of the tumor specimens to that of water was 0.99 for all energies.
Image quality degradation by light scattering processes in high performance display devices for medical imaging
Authors: Badano Aldo
Published: July 2002

This thesis addresses the characterization of light scattering processes that degrade image quality in high performance electronic display devices for radiography. Using novel experimental and computational tools, we study the lateral diffusion of light in emissive displays that causes extensive veiling glare and significant reduction of the contrast. In addition, we examine the deleterious effects of ambient light reflections that affect the contrast of low luminance regions, and superimpose unwanted structured signal. To model veiling glare and display reflections, we use a Monte Carlo light transport simulation code, DETECT‐II, that tracks individual photons through multiple scattering events. The simulation accounts for the photon polarization state, and provides descriptions for rough surfaces and thin film coatings. A new experimental method to measure veiling glare is described based on a conic collimated probe that minimizes unwanted contributions from bright areas. We show that veiling glare ratios in the order of a few hundreds can be measured with an uncertainty of a few percent. For a high performance medical imaging monitor with anti‐reflective coating, the veiling glare ratio for a 1 cm diameter dark spot was measured to be 240. Finally, we introduce experimental techniques for measurements of display reflectance, and we compare measured reflection coefficients with Monte Carlo estimates. In spite of having comparable reflection coefficients, the low maximum luminance of current cathode‐ray tube devices worsens the effect of ambient light reflections when compared to radiographic film. Flat panel technologies can perform even better than film due to a thin faceplate, increased light absorption, and high brightness.
MABDOSE. I: Characterization of a general purpose dose estimation code
Authors: Johnson Timothy K. , McClure David , McCourt Steven
Published: July 2002

The MABDOSE software represents a general tool to perform internal radiation dosimetry. It uses a three‐dimensional lattice in which to conduct radiation transport, scoring energy deposition in discrete voxels. The dosimetry system currently relies on the same algorithm used by the MIRD committee for photon transport, and assumes local deposition of particulate energy. A mathematical description of the dosimetry system's implementation is given. Additionally, a characterization of the system with respect to memory requirements, data libraries used, and simulation timing benchmarks, is presented. Validation of the software is presented in a companion manuscript.
Miniature scintillating detector for small field radiation therapy
Authors: Létourneau D. , Pouliot J. , Roy R.
Published: July 2002

In planning stereotactic radiosurgery treatments, depth dose curves, profiles, and dose rate of treatment beams are difficult to obtain with conventional detectors because of loss of lateral electronic equilibrium and volume averaging. A scintillating detector with high spatial resolution and good reliability has been developed to overcome this problem. The miniature dosimeter consists of two identical radiation‐resistant 10 m long silica optical fibers, each connected to an independent silicon photodiode. A small cylindrical polystyrene scintillator (3.9 mm3) is optically glued to the detection fiber. The light seen by the photodiode connected to this fiber arises from fluorescence of the scintillator and from the Cerenkov effect produced in silica. The reference signal produced by the fiber without scintillator is used to subtract the Cerenkov light contribution from the raw detector response. The sensitive volume of the scintillating detector is nearly water‐equivalent and thus minimizes dose distribution perturbation in water. The miniature dosimeter has a spatial resolution comparable to the film‐densitometer system. Profiles of 1 cm diam, 6 MV photon beam measured with both systems show very similar shapes. Furthermore, the use of photodiodes instead of photomultiplier tubes gives a better stability response and offers the possibility to perform absolute dosimetry.
Evaluation of a commercial three‐dimensional electron beam treatment planning system
Authors: Ding G. X. , Cygler J. E. , Zhang G. G. , Yu M. K.
Published: July 2002

We evaluated a commercial three‐dimensional (3D) electron beam treatment planning system (CADPLAN V.2.7.9) using both experimentally measured and Monte Carlo calculated dose distributions to compare with those predicted by CADPLAN calculations. Tests were carried out at various field sizes and electron beam energies from 6 to 20 MeV. For a homogeneous water phantom the agreement between measured and CADPLAN calculated dose distributions is very good except at the phantom surface. CADPLAN is able to predict hot and cold spots caused by a simple 3D inhomogeneity but unable to predict dose distributions for a more complex geometry where CADPLAN underestimates dose changes caused by inhomogeneity. We discussed possible causes for the inaccuracy in the CADPLAN dose calculations. In addition, we have tested CADPLAN treatment monitor unit and electron cut‐out factor calculations and found that CADPLAN predictions generally agree with manual calculations.
Echolocation behavior of big brown bats, Eptesicus fuscus, in the field and the laboratory
Authors: Surlykke Annemarie , Moss Cynthia F.
Published: July 2002

Echolocation signals were recorded from big brown bats, Eptesicus fuscus, flying in the field and the laboratory. In open field areas the interpulse intervals (IPI) of search signals were either around 134 ms or twice that value, 270 ms. At long IPI’s the signals were of long duration (14 to 18–20 ms), narrow bandwidth, and low frequency, sweeping down to a minimum frequency (Fmin) of 22–25 kHz. At short IPI’s the signals were shorter (6–13 ms), of higher frequency, and broader bandwidth. In wooded areas only short (6–11 ms) relatively broadband search signals were emitted at a higher rate (avg. IPI=122 ms) with higher Fmin (27–30 kHz). In the laboratory the IPI was even shorter (88 ms), the duration was 3–5 ms, and the Fmin 30–35 kHz, resembling approach phase signals of field recordings. Excluding terminal phase signals, all signals from all areas showed a negative correlation between signal duration and Fmin, i.e., the shorter the signal, the higher was Fmin. This correlation was reversed in the terminal phase of insect capture sequences, where Fmin decreased with decreasing signal duration. Overall, the signals recorded in the field were longer, with longer IPI’s and greater variability in bandwidth than signals recorded in the laboratory.
Theory of frequency dependent acoustics in patchy-saturated porous media
Authors: Johnson David Linton
Published: July 2002

The theory of the dynamic bulk modulus, K̃(ω), of a porous rock, whose saturation occurs in patches of 100% saturation each of two different fluids, is developed within the context of the quasi-static Biot theory. The theory describes the crossover from the Biot–Gassmann–Woods result at low frequencies to the Biot–Gassmann–Hill result at high. Exact results for the approach to the low and the high frequency limits are derived. A simple closed-form analytic model based on these exact results, as well as on the properties of K̃(ω) extended to the complex ω-plane, is presented. Comparison against the exact solution in simple geometries for the case of a gas and water saturated rock demonstrates that the analytic theory is extremely accurate over the entire frequency range. Aside from the usual parameters of the Biot theory, the model has two geometrical parameters, one of which is the specific surface area, S/V, of the patches. In the special case that one of the fluids is a gas, the second parameter is a different, but also simple, measure of the patch size of the stiff fluid. The theory, in conjunction with relevant experiments, would allow one to deduce information about the sizes and shapes of the patches or, conversely, to make an accurate sonic-to-seismic conversion if the size and saturation values are approximately known.
A k-space method for coupled first-order acoustic propagation equations
Authors: Tabei Makoto , Mast T. Douglas , Waag Robert C.
Published: July 2002

A k-space method for large-scale simulation of ultrasonic pulse propagation is presented. The present method, which solves the coupled first-order differential equations for wave propagation in inhomogeneous media, is derived in a simple form analogous to previous finite-difference methods with staggered spatial and temporal grids. Like k-space methods based on second-order wave equations, the present method is exact for homogeneous media, unconditionally stable for “slow” [c(r)⩽c0] media, and highly accurate for general weakly scattering media. In addition, unlike previous k-space methods, the form of the method allows straightforward inclusion of relaxation absorption and perfectly matched layer (PML) nonreflecting boundary conditions. Numerical examples illustrate the capabilities of the present k-space method. For weakly inhomogeneous media, accurate results are obtained using coarser temporal and spatial steps than possible with comparable finite-difference and pseudospectral methods. The low dispersion of the k-space method allows accurate representation of frequency-dependent attenuation and phase velocity associated with relaxation absorption. A technique for reduction of Gibbs phenomenon artifacts, in which compressibility and exponentially scaled density functions are smoothed by half-band filtering, is introduced. When employed together with this smoothing technique, the k-space method provides high accuracy for media including discontinuities, high-contrast inhomogeneities, and scattering structures smaller than the spatial grid resolution.
Inter-individual differences in binaural detection of low-frequency or high-frequency tonal signals masked by narrow-band or broadband noise
Authors: Bernstein Leslie R. , Trahiotis Constantine , Hyde Erika L.
Published: July 2002

Detection thresholds for either 500-Hz tones or 4-kHz tones were measured for a group of 19 listeners utilizing the interaural configurations NoSo and NoSπ. Both broadband (100–8500 Hz) noises and narrow-band (50-Hz-wide) noises served as maskers. In addition, direct measures of the listeners’ sensitivities to changes in interaural temporal differences (ITDs) and interaural intensitive differences (IIDs) were measured using 400-Hz-wide noises centered at 500 Hz or 4 kHz. A rather large range of inter-individual differences in threshold was observed for 4-kHz tonal signals masked by narrow-band noise in the NoSπ configuration. This result is consistent with several sets of data from our previous experiments conducted over more than a decade. A broad range of thresholds was also obtained for 500-Hz tonal signals masked by narrow-band noise in the NoSπ configuration. This outcome, coupled with the fact that the use of a broadband masker did not yield a large distribution of thresholds for the detection of a 500-Hz tone masked by a broad band of noise, suggests that it is the use of a narrow-band masker, per se, that results in a large range of thresholds. Statistical analyses revealed that thresholds in the NoSπ detection tasks were not highly correlated with thresholds measured in the ITD- and the IID-discrimination tasks. Nevertheless, the five listeners who were the most sensitive in the narrow-band NoSπ detection and the five listeners who were the least sensitive in the narrow-band NoSπ detection tasks were those who were the most and least sensitive, respectively, to changes in ITDs and to changes in IIDs.
An acoustic integration model (AIM) for assessing the impact of underwater noise on marine wildlife
Authors: Ellison William T. , Weixel Karen , Clark Christopher W.
Published: July 2002

In recent years there has been a heightened awareness of the environmental impact of noise, especially man-made noise, on marine wildlife. The National Environmental Policy Act (NEPA), Executive Order 12114, The Endangered Species Act, The Marine Mammal Protection Act, and the Coastal Zone Management Act each provide for varying levels of regulation and control in protection of the environment and marine wildlife. In order to assess the environmental impact of a sound source, one must predict the sound levels that any given species will be exposed to over time in the locale of the source’s radiated field. This is a three-part process involving (1) the ability to measure or predict an animal’s location in space in time, (2) the ability to measure or predict the sound field at these times and locations, and finally, (3) integration of these two data sets so as to determine the net acoustic impact of the sound source on any specific animal. This paper describes a modeling methodology for accomplishing this task. Model inputs required to specify the acoustic environment, animal distribution and behavior, and sound source characteristics are discussed in detail. The AIM model output capabilities are described together with topical examples.
Viscoelastic shear properties of human vocal fold mucosa: Measurement methodology and empirical results
Authors: Chan Roger W. , Titze Ingo R.
Published: July 2002

A standard method for the empirical rheological characterization of viscoelastic materials was adopted to measure the viscoelastic shear properties of human vocal-fold mucosal tissues (the superficial layer of lamina propria). A parallel-plate rotational rheometer was employed to measure shear deformation of viscoelastic tissue samples, which were deformed between two rigid circular plates rotating in small-amplitude sinusoidal oscillations. Elastic and viscous shear moduli of the samples were then quantified as a function of oscillation frequency (0.01 to 15 Hz) based on shear stresses and strains recorded by the rheometer. Data were obtained from 15 excised human larynges (10 male and 5 female). Results showed that the elastic shear modulus μ and the damping ratio ζ of human vocal-fold mucosa were relatively constant across the range of frequencies observed, while the dynamic viscosity η decreased monotonically with frequency (i.e., shear thinning). Intersubject differences in μ and η as large as an order of magnitude were observed, part of which may reflect age-related and gender-related differences. Some molecular interpretations of the findings are discussed.
Rheological properties and adhesive failure of thin viscoelastic layers
Authors: Crosby A. J. , Shull K. R. , Lin Y. Y. , Hui C.-Y.
Published: July 2002

Methods have been developed for measuring the linear viscoelastic properties of thin adhesive layers, and for determining the stress intensity factor characterizing the driving force for adhesive failure. Both methods involve bringing a hemispherical indenter in contact with the adhesive layer while simultaneously monitoring the load, displacement, and radius of contact between the indenter and the adhesive. Dynamic moduli for the adhesive layer are obtained by oscillating the indenter, and the adhesive properties are obtained by pulling the indenter completely out of contact with the adhesive layer. Existing theories of viscoelastic contact mechanics were extended to account for the fact that the adhesive layer thickness is not substantially larger than the contact radius, as is generally assumed. A variety of correction factors were introduced that depend on the ratio of the contact radius to the adhesive layer thickness. These methods were applied to a model adhesive based on an acrylic triblock copolymer. Determination of the time-dependent creep and relaxation functions for this material was simplified by the power-law frequency response of the dynamic moduli. The large stress intensity factors observed were related to a Dugdale model of the cohesive zone at the contact edge.
Advances in Point‐Of‐Care Testing for Emergency Response, Infectious Diseases, and Critical Care — Novel Technologies, Practice Standards, and Improved Outcomes
Authors: Füzéry Anna K. , Kost Gerald J. , Tran Nam K.
Published: September 2022

We present strategies forpoint‐of‐care testing(POCT) that pave the way for diagnostic portals from homes to intensive care. Now well recognized worldwide by the public and professionals alike, POCT has become ubiquitous. Its scope encompasses mobile field rescue, emergency rooms, and hospital intensive care, where rapid test results help stabilize critically ill patients.

We introduce novel technologies and insights for effective application of POCT, including identifying infectious pathogens. We chronicle the discovery of the clinical significance of ionized calcium, the ‘fifth electrolyte,’ an obligatory whole‐blood analyte. We tabulate outcomes associated with whole‐blood analysis, which has progressed significantly across the globe.

Progressively endemic, coronavirus disease 2019 is catapulting POCT to new heights. This striking expansion calls for more practical know‐how among laboratorians and public health officials, careful planning of POC strategies in healthcare small‐world networks, and support by national guidelines and policies, especially in limited‐resource settings.

Technical, clinical, and cultural advances predict exponential growth as the world embraces faster, smaller, and smarter connected diagnostic decision making where it counts the most, at points of need. This POC paradigm shift means learning novel principles and appreciating new standards for POC devices used on ambulances for emergency rescue, so we start there.
Information Processing
Authors: Bailey Rachel L.
Published: September 2022

The information processing perspective approaches studying human behavior by focusing on the mental processes underlying that behavior. Multiple models exist that have been extended and revised. These models differ in structure, function, and emphasis, but current models generally assume that cognition is a limited capacity process that occurs over time and is highly influenced by affective processes and individual differences.
Toolkit article: Approaches to measuring social inequities in health in human biology research
Authors: Thayer Zaneta , Uwizeye Glorieuse , McKerracher Luseadra
Published: September 2022

Across populations, human morbidity and mortality risks generally follow clear gradients, with socially‐disadvantaged individuals and groups tending to have higher morbidity and mortality at all life stages relative to those more socially advantaged. Anthropologists specialize in understanding the proximate and ultimate factors that shape variation in human biological functioning and health and are therefore well‐situated to explore the relationships between social position and health in diverse ecological and cultural contexts. While human biologists have developed sophisticated methods for assessing health using minimally‐invasive methods, at a disciplinary level, we have room for conceptual and methodological improvement in how we frame, measure, and analyze the social inequities that might shape health inequities. This toolkit paper elaborates on some steps human biologists should take to enhance the quality of our research on health inequities. Specifically, we address: (1) how to frame unequal health outcomes (i.e., inequalities vs. disparities vs. inequities) and the importance of identifying our conceptual models of how these inequities emerge; (2) how to measure various axes of social inequities across diverse cultural contexts, and (3) approaches to community collaboration and dissemination. We end by discussing (4) future directions in human biology research of health inequities, including understanding the ultimate causes of sensitivity to social inequities and transitioning from research to action.
Electrochemical Cross‐Electrophile‐Coupling for Transition‐Metal‐Free Allylic Carboxylation with Ambient CO2
Authors: Zhao Rong , Lin Zhipeng , Maksso Isaac , Struwe Julia , Ackermann Lutz
Published: September 2022

The use of CO2as a C1 building block to access carboxylic acids is one of the key aspects in the context of carbon capture and utilization (CCU). Herein we report on an electrochemical carboxylation of allyl esters with CO2at atmospheric pressure. This strategy enabled to the synthesis of diverse carboxylic acids without the need for a transition metal catalyst. Furthermore, the mechanism was studied through ICP‐MS analysis and cyclic voltammetry studies for the cross‐electrophile CO2coupling.
Exploring the frontiers of deep underground sciences and engineering—China Yunlong Lake Laboratory is striving to be the best
Authors: Hu Lihua , Wang Jianguo , Karrech Ali , Li Xiaozhao , Zhao Peng , Liu Lulu
Published: September 2022

This paper introduces the establishment of deep underground infrastructure for science and engineering research. First, the representative deep underground research laboratories and facilities in the world and their functions were summarized and reviewed. Then, the plan and service target of China Yulong Lake Laboratory were proposed for the storage of resources and energy, as well as the sealing of hazardous waste in deep underground space. On this basis, this paper reveals how the facility addresses its key scientific issue on “The law of fluid matter migration in deep underground space” and engineering significance. Finally, the construction progress of the facility components was demonstrated in details. As is hoped, this paper would provide useful reference to the deep underground research community; meanwhile, international collaboration on deep underground research is highly welcome.
Supporting graduate field leadership through community‐sourced advice, action, and policy
Authors: Hayes Katherine , Carter Trevor , Cook Phoebe , Twaddell Erin , Buma Brian
Published: September 2022

Ecology and environmental science graduate degrees often involve fieldwork, frequently led by the graduate student. Few formal resources exist to support graduate students in successfully planning and implementing a data collection field campaign, even though this experience may be fundamental to completing a graduate degree. Graduate fieldwork requires leading and managing a team, often in unique circumstances (including long hours, remote regions, etc.), and therefore can be challenging even for those with previous leadership or field experience. Our objectives were to (1) collect general advice for graduate students on leading fieldwork safely and effectively, (2) solicit specific suggestions on resources and actions to take before, during, and after the field season, and (3) develop a series of recommendations for labs, departments, and universities to better prepare and support their students. We developed a survey to solicit community input and distributed it widely to the ecological sciences community via email LISTSERVs and social media. Here, we present results from the survey responses, including a summary of the perceived challenges that graduate students face while leading their own fieldwork, suggestions for how to prepare and complete fieldwork successfully, and a compilation of resources. Graduate field leaders can improve success via clear communication, risk assessment and procedural planning implemented before, during, and after the field season. Labs, principal investigators, departments, and professional societies can support graduate field leaders by formalizing institutional resources, financial support, and incentivizing skill development. Field leadership is a critical skill to develop during graduate education, and contributes to the success, retention, and advancement of researchers in the natural sciences.
“We can hardly even do it nowadays. So, what's going to happen in 5 years from now, 10 years from now?” The health and community care and support needs and preferences of older people living with HIV in Ontario, Canada: a qualitative study
Authors: Murzin Kate , Racz Elizabeth , Behrens D. M. , Conway Tracey , Da Silva George , Fitzpatrick Eimear , Lindsay Joanne D. , Walmsley Sharon L. ,   the PANACHE study team
Published: September 2022

Introduction

The population of people living with HIV (PLWH) is ageing consequent to effective treatment and a steady stream of new diagnoses among older adults. PLWH experience a greater burden of age‐related comorbidities and poorer social determinants of health compared to their HIV‐negative peers, yet comprehensive requisites for care and support as PLWH age remain poorly understood. Preferences And Needs for Ageing Care among HIV‐positive Elderly people in Ontario, Canada (PANACHE ON), explored the health and community care and social support needs and preferences of a diverse group of older PLWH (age 60+) and described life course experiences among older PLWH that shape these needs and preferences and whether they are met.

Methods

PANACHE ON was a qualitative community‐based participatory research study. In‐person focus groups using a semi‐structured interview guide were co‐facilitated by pairs of trained older PLWH from July to October 2019. Purposive sampling bolstered the inclusion of communities disproportionately affected by HIV in Ontario. Descriptive analysis was used to summarize demographic data; participatory data analysis was conducted by a subset of the research team, with transcripts double‐coded and analysed using NVIVO 12 Plus.

Results

A total of 73 PLWH participated, 66% identified as men. The mean age was 64 years (range 55–77) and median time living with HIV was 23 years (range 2–37). The current and anticipated needs of older PLWH, many of which were only partially met, included necessities such as food and housing, mobility and sensory aids, in‐home support, social and emotional support, transportation and information. Three experiences—trauma, stigma and uncertainty—intersected in the lives of many of our participants, shaping their needs for care and support, and impacting the ease with which these needs were met.

Conclusions

Unmet health and social needs and limited control over the availability and accessibility of ageing‐related care and support due to resource constraints or reduced capacity for self‐advocacy results in anxiety about the future among older PLWH, despite their well‐developed coping strategies and experience navigating systems of care. These study findings will inform the development of the first national needs assessment of older PLWH in Canada.
Neurosurgical Implant Safety in 7 T MRI: A Scoping Review
Authors: Shaffer Annabelle , Weisbaum David , Naik Anant , Anderson Aaron , Wszalek Tracey , Cohen Mark , Sutton Brad , Webb Andrew , Damon Bruce , Arnold Paul M.
Published: September 2022

The use of 7 Tesla (T) magnetic resonance imaging (MRI) is expanding across neurosurgical and neurologic specialties. However, few neurosurgical‐related implants have been tested for safety at 7 T, limiting its use in patients with cranial fixation, shunt placements, and other implants. Implant safety can be determined via the American Society for Testing Materials International (ASTM) guidelines. To assess the current state of neurosurgical implant safety at 7 T, a systematic search was performed using PubMed, MEDLINE, Web of Knowledge, and citation matching. Studies written in English that included at least one neurosurgical implant and at least one safety outcome were included. Data were extracted for implant studied, implant composition, deflection angle, torque, temperature change, and ASTM guidelines followed. PRISMA reporting guidelines for scoping reviews were followed. Overall, 18 studies consisting of 45 unique implants were included. Implants included cranial fixation devices, aneurysm clips, spinal rods, pedicle screws, ventriculoperitoneal (VP) shunts, deep brain stimulation devices, and electroencephalogram (EEG) caps and electrodes. Cranial fixation devices, deep brain stimulation devices, spinal rods, and pedicle screws are likely 7 T MRI compatible based on outcomes reported. Aneurysm clips and EEG devices had variable safety outcomes. The VP shunts studied lost functionality after 7 T MRI exposure. We identified several implants that are likely compatible with 7 T MRI. Given the growth in 7 T imaging and expansion of the technology, neurosurgical implants should be constructed with the aforementioned considerations. Caution must be taken with all implants, especially aneurysm clips, programmable VP shunts, and EEG recording devices. It is also noteworthy that several implant testing reports did not report following ASTM standards. This scoping review seeks to concisely summarize all neurosurgical‐related implants that have been tested for safety in 7 T MRI.

Evidence Level

2

Technical Efficacy

Stage 2