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The products that we use in our living environment greatly assist us in maintaining health and independence as we age. Much research has been conducted on the physical ergonomic needs in product design for older people, overlooking an understanding of the ‘softer’ functionality that domestic products offer. Through an ethnographic case study of older peoples' cooking and heating product needs (N=40), this paper presents 1) a theoretical framework which supports the need for designers to consider social and emotional connections when designing domestic products for older people and 2) practical implications and requirements for future designers to consider when designing these products. In this paper, I encourage designers to consider the reflective and visceral connections domestic products hold and how products can both inhibit and increase social inclusion.

COVID-19 has had an extreme effect on older people. Now more than ever we need collaborative approaches to address complex issues within research on aging. However, the pandemic has dramatically changed the way we conduct, interact, and organize research within interdisciplinary groups. This paper describes a case study of how an interdisciplinary institute for research on aging has managed the process of change during COVID-19 restrictions. A design lead, researcher centered approach was used to understand the needs of researchers as they adapted across 6 months. Firstly, an online survey (n=51) was conducted to understand the scope of change and needs. The survey found broad themes ranging from assistance with finding additional funding to adjusting current research proposals. Following the survey, two Co-Design Sessions were conducted. The first session (n=53) diverged thinking to scope ideas from the survey and actionable themes were created. The second session (n=36) was conducted to converge thinking and focus on solutions based on one of these themes. The results revealed a diversity of ideas addressing the needs of interdisciplinary researchers in aging. These ideas spanned from exploring the capacity to do research remotely and creating virtual collaboration spaces to rethinking stakeholder engagement. Received: 1 July 2021Accepted: 12 October 2021

Pulsed low-intensity focused ultrasound (PLIFUS) has shown promise in inducing neuromodulation in several animal and human studies. Therefore, it is of clinical interest to develop experimental platforms to test repetitive PLIFUS as a therapeutic modality in humans with neurologic disorders. In the study described here, our aim was to develop a laboratory-built experimental device platform intended to deliver repetitive PLIFUS across the hippocampus in seizure onset zones of patients with drug-resistant temporal lobe epilepsy. The system uses neuronavigation targeting over multiple therapeutic sessions. PLIFUS (548 kHz) was emitted across multiple hippocampal targets in a human subject with temporal lobe epilepsy using a mechanically steered piezoelectric transducer. Stimulation was delivered up to 2.25 W/cm2 spatial peak temporal average intensity (free-field equivalent), with 36%-50% duty cycle, 500-ms sonications and 7-s inter-stimulation intervals lasting 140 s per target and repeated for multiple sessions. A first-in-human PLIFUS course of treatment was successfully delivered using the device platform with no adverse events.

We developed a method to create customizable phantoms suitable for endocavitary imaging and interventional research, based on the fabrication of an acrylic phantom mold, and development of a phantom matrix composed of gelatin, agar, graphite particles, and propanol. Our phantom was mechanically stable, easily fabricated, and highly adjustable, and its ultrasound (US) and magnetic resonance imaging (MRI) scans showed the qualification for the procedure guidance compared with the human prostate image using the same US system. To test the feasibility of the phantom for the research, the seeds placement guided by MRI/US fusion was performed, and the overall test error (distance from the seed center to the virtual lesion center in olives) was 2.59 ± 0.59 mm. We have created a simple, low-cost, configurable, gelatin-based phantom and tested its feasibility for simulating endorectal interventional US procedures. The design of the phantom mold and matrix is likely to be useful to the broader medical training community, and the preliminary data from the experiment of MRI/US-guided seeds placement showed its potential to test the clinical hypothesis in US research.

Creative problem-solving has been identified as one of the most critical future-proof skillsets we can develop in our society. When educating future designers, entrepreneurship skills are now considered essential; however, designers find it difficult to establish themselves as entrepreneurs. Therefore, graduate designers are increasingly in need of these skills to complement their creative ability. This paper offers information to academic institutions looking to implement entrepreneurship modules in existing design and creative programmes. The paper seeks to understand the entrepreneurship skills required for product design graduates through a case study. Current teaching practice is described, and interviews and co-design sessions with relevant stakeholders are conducted to inform future entrepreneurship education for product design students. From these findings, a module descriptor entitled ‘Entrepreneurship for Designers’ was created for an existing programme and delivered through both practice and theory. This module is intended to provide an understanding of the entrepreneurship process and to offer students the confidence to pursue design-related ventures post-graduation.

An introduction to the physics and technological principles of diagnostic ultrasound is presented, including (1) a discussion of ultrasound-tissue interactions; (2) the pulse-echo technique; (3) transducers and ultrasound machine instrumentation for the detection and signal processing of echoes and image formation; (4) Doppler ultrasound; (5) B-mode and Doppler ultrasound artifacts. An overview of advanced ultrasound modes including harmonic and compound imaging, elastography, 3D imaging, ultrasound contrast, bioeffects, and safety of ultrasound is also provided.

COVID-19 has impacted not only the health of citizens, but also the various factors that make up our society, living environments, and ecosystems. This pandemic has shown that future living will need to be agile and flexible to adapt to the various changes in needs of societal populations. Digital technology has played an integral role during COVID-19, assisting various sectors of the community, and demonstrating that smart cities can provide opportunities to respond to many future societal challenges. In the decades ahead, the rise in aging populations will be one of these challenges, and one in which the needs and requirements between demographic cohorts will vary greatly. Although we need to create future smart age-friendly ecosystems to meet these needs, technology still does not feature in the WHO eight domains of an age-friendly city. This paper extends upon Marston and van Hoof&rsquo, s &lsquo, Smart Age-friendly Ecosystem&rsquo, (SAfE) framework, and explores how digital technology, design hacking, and research approaches can be used to understand a smart age-friendly ecosystem in a post-pandemic society. By exploring a series of case studies and using real-life scenarios from the standpoint of COVID-19, we propose the &lsquo, Concept of Age-friendly Smart Ecologies (CASE)&rsquo, framework. We provide an insight into a myriad of contemporary multi-disciplinary research, which are capable to initiate discussions and bring various actors together with a positive impact on future planning and development of age-friendly ecosystems. The strengths and limitations of this framework are outlined, with advantages evident in the opportunity for towns, regions/counties, provinces, and states to take an agile approach and work together in adopting and implement improvements for the greater benefits of residents and citizens.

In March 2020 the United Nations published an open brief for the creative community to propose interventions to the unfolding COVID-19 pandemic. However, when faced with unprecedented wicked problems such as these, the rigour of design and creative processes can tested. COVID-19 has demonstrated how important human centred design responses are in understanding the worldviews and ecosystems of users. Ad hoc design responses or design hacks have demonstrated that they have a role to play in how we create our future individual, community and societal ecosystems. In terms of age friendly design, this pandemic makes us envision what should be, furthermore, how we could create better products and services through technology. For our ageing communities ‘Cocooning’ and other social restriction measures have exposed technological deficiencies for the needs of older people and opens up questions of our future preparedness for a growing ageing society. Now more than ever, designers need to understand the behavioural mind-set of older people in their own ecosystem and understand existing mental models. In this opinion piece we posit what acts of design hacking can lead us to greater understanding of users mental models and therefore better understanding of technology needs for both older and younger adults. While presenting various examples of how design hacking is conducted by citizens and participants alike, it shows that it offers designers differing perspectives, experiences and inspiration for technology.

As focused ultrasound for blood-brain barrier disruption (FUS-BBBD) has progressed to human application, it has become necessary to consider the potential effects of prior irradiation treatments. Using a murine model, we examined the effects of whole-brain irradiation on FUS-BBBD. We first subjected half of the experimental cohort to daily 3-Gy whole-brain irradiation for 10 consecutive days. Then, microbubble-assisted FUS-BBBD was performed unilaterally while the contralateral sides served as unsonicated controls. FUS-BBBD, as evident by measuring the fluorescence yield of extravasated trypan blue dye, was identified at all sites with minimal or no apparent pathology. The peak fluorescence intensity caused by extravasated dye in the sonicated region was 17.5 ± 12.1% higher after radiation and FUS-BBBD than after FUS-BBBD alone, suggesting that prior radiation of the brain may be a sensitizing factor for FUS-BBBD. Radiation alone-without FUS-BBBD-resulted in mild BBB disruption. Hemorrhagic petechiae were observed in 9 of 12 radiated brains, with 77% of them clearly located outside the sonicated area; no petechiae were found in non-irradiated animals. This radiation protocol did not appear to increase the risk for vascular damage associated with FUS-BBBD.

Intergenerational initiatives in post-secondary settings have demonstrated health and social benefits. However, there is a lack of detail with regard to the process by which such initiatives are conceptualized and the role of older and younger users in their development. Guided by the principles of an Age-Friendly University (AFU) alongside elements from a 'Design Thinking' approach, this project outlines the process undertaken to design a new intergenerational space to promote intergenerational connectivity. An online student survey (n = 504; 72.2% female) and focus groups were conducted with older adults (n = 22; 12 females; aged 70-95), which found similar themes across age groups with respect to: 1) past intergenerational experiences; 2) perceived benefits/challenges of accessing the space, and; 3) activity suggestions. Using these findings, alongside direct stakeholder input, Occupational Therapy students developed programming and design suggestions for the space in question aimed at strengthening interactions across age and ability. Results from this process indicate consulting with older and younger users can circumvent potential challenges and inform the design of campus-based initiatives that can promote intergenerational exchange. yes

Large organisations use design and design thinking to create value; however, there is a low awareness and practice of design and design thinking in smaller businesses. 69% of Irish businesses never use design, or use it only at a superficial level (DJEI, 2016). Previous research on the relationship between design and the wider-enterprise base in Ireland has focused on highly innovative and successful businesses that are already accustomed to design and have ten or more employees. The result of these studies has produced stories of how design creates value for each business, making it difficult to understand how it is applied in, and relates to, other businesses, particularly micro- enterprises without design competence. This paper aims to contribute to the academic field of design and wider-enterprise base in Ireland, in relation to design thinking and regional micro-enterprises who are not accustomed to design. It explores how design thinking offers strategic value to these businesses by building understanding of the identity and purpose of the business for the owner. yes

One of the key unmet needs to improve long-term outcomes of heart transplantation is to develop accurate, noninvasive, and practical diagnostic tools to detect transplant rejection. Early intragraft inflammation and endothelial cell injuries occur prior to advanced transplant rejection. We developed a novel diagnostic imaging platform to detect early declines in microvascular perfusion (MP) of cardiac transplants using contrast-enhanced ultrasonography (CEUS). The efficacy of CEUS in detecting transplant rejection was tested in a murine model of heart transplants, a standard preclinical model of solid organ transplant. As compared to the syngeneic groups, a progressive decline in MP was demonstrated in the allografts undergoing acute transplant rejection (40%, 64%, and 92% on days 4, 6, and 8 posttransplantation, respectively) and chronic rejection (33%, 33%, and 92% on days 5, 14, and 30 posttransplantation, respectively). Our perfusion studies showed restoration of MP following antirejection therapy, highlighting its potential to help monitor efficacy of antirejection therapy. Our data suggest that early endothelial cell injury and platelet aggregation contributed to the early MP decline observed in the allografts. High-resolution MP mapping may allow for noninvasive detection of heart transplant rejection. The data presented have the potential to help in the development of next-generation imaging approaches to diagnose transplant rejection.

The world’s population is ageing; researchers have an increasingly important role to play in innovating new products, appliances and services to allow for better everyday living conditions of this ageing demographic. Health, wellbeing and age in place needs are of particular importance in Ireland as research has revealed that as a nation we are living longer in ill health (McGill, 2009). The most fundamental domestic products to health, wellbeing and in the promotion of ageing in place are cooking and heating products, however little design research has been carried out in this area. To inquire into the context of usability in older adults, ethnographic research has been conducted within the homes of participant older adults to obtain a true insight into user needs in cooking and heating products. This involved a yearlong (Spring, Summer, Autumn and Winter) study with forty participants over the age of 70 years across Ireland and from various socio-economic groups. From this study prototypes will be created and user tested by older adults to determine appropriate design criteria for these products.

Recent studies have attempted to dispel the idea of the longitudinal mode being the only significant mode of ultrasound energy transport through the skull bone. The inclusion of shear waves in propagation models has been largely ignored because of an assumption that shear mode conversions from the skull interfaces to the surrounding media rendered the resulting acoustic field insignificant in amplitude and overly distorted. Experimental investigations with isotropic phantom materials and ex vivo human skulls demonstrated that, in certain cases, a shear mode propagation scenario not only can be less distorted, but at times allowed for a substantial (as much as 36% of the longitudinal pressure amplitude) transmission of energy. The phase speed of 1.0-MHz shear mode propagation through ex vivo human skull specimens has been measured to be nearly half of that of the longitudinal mode (shear sound speed = 1500±140 m/s, longitudinal sound speed = 2820±40 m/s), demonstrating that a closer match in impedance can be achieved between the skull and surrounding soft tissues with shear mode transmission. By comparing propagation model results with measurements of transcranial ultrasound transmission obtained by a radiation force method, the attenuation coefficient for the longitudinal mode of propagation was determined to between 14 Np/m and 70 Np/m for the frequency range studied while the same for shear waves was found to be between 94 Np/m and 213 Np/m. This study was performed within the frequency range of 0.2–0.9 MHz. (E-mail: white@bwh.harvard.edu)

The development of high-intensity ultrasound technology into a system for performing image-guided noninvasive ultrasound neurosurgery has developed at a relatively rapid pace in the past few years. Magnetic resonance imaging has contributed significantly to this development by providing a modality by which percutaneous ultrasound treatments can be preoperatively planned, intraoperatively guided and postoperatively evaluated for safety and efficacy. Especially in the case of transcranial ultrasound therapies, the structural identification and thermal monitoring of cortical structures is essential to avoid overheating at the skull-brain interface and to avoid the sonication of critical structures. This chapter briefly describes the physics of transmitting ultrasound through the skull and the technological advances that circumvented the physical limits imposed by the skull bone. The integration of magnetic resonance guidance and monitoring is detailed, along with an overview of ongoing studies with a commercially developed magnetic resonance imaging-compatible hemispherical transducer array.

A full-wave Helmholtz model of continuous-wave (CW) ultrasound fields may offer several attractive features over widely used partial-wave approximations. For example, many full-wave techniques can be easily adjusted for complex geometries, and multiple reflections of sound are automatically taken into account in the model. To date, however, the full-wave modeling of CW fields in general 3D geometries has been avoided due to the large computational cost associated with the numerical approximation of the Helmholtz equation. Recent developments in computing capacity together with improvements in finite element type modeling techniques are making possible wave simulations in 3D geometries which reach over tens of wavelengths. The aim of this study is to investigate the feasibility of a full-wave solution of the 3D Helmholtz equation for modeling of continuous-wave ultrasound fields in an inhomogeneous medium. The numerical approximation of the Helmholtz equation is computed using the ultraweak variational formulation (UWVF) method. In addition, an inverse problem technique is utilized to reconstruct the velocity distribution on the transducer which is used to model the sound source in the UWVF scheme. The modeling method is verified by comparing simulated and measured fields in the case of transmission of 531 kHz CW fields through layered plastic plates. The comparison shows a reasonable agreement between simulations and measurements at low angles of incidence but, due to mode conversion, the Helmholtz model becomes insufficient for simulating ultrasound fields in plates at large angles of incidence.

A new transskull propagation technique, which deliberately induces a shear mode in the skull bone, is investigated. Incident waves beyond Snell's critical angle experience a mode conversion from an incident longitudinal wave into a shear wave in the bone layers and then back to a longitudinal wave in the brain. The skull's shear speed provides a better impedance match, less refraction, and less phase alteration than its longitudinal counterpart. Therefore, the idea of utilizing a shear wave for focusing ultrasound in the brain is examined. Demonstrations of the phenomena, and numerical predictions are first studied with plastic phantoms and then using an ex vivo human skull. It is shown that at a frequency of 0.74 MHz the transskull shear method produces an amplitude on the order of--and sometimes higher than--longitudinal propagation. Furthermore, since the shear wave experiences a reduced overall phase shift, this indicates that it is plausible for an existing noninvasive transskull focusing method [Clement, Phys. Med. Biol. 47(8), 1219-1236 (2002)] to be simplified and extended to a larger region in the brain.

Ultrasound imaging has become a standard method for evaluating patients who have suffered blunt trauma. Specifically, focused assessment with sonography in trauma, commonly known as the “FAST exam,” is regularly employed to detect free intraperitoneal, intrathoracic, and pericardial fluid in the setting of trauma. Currently, evaluation of the intracranial space remains a significant missing component of the FAST exam because the skull bone acts as a physical barrier to ultrasound transmission for existing approaches in pulse-echo ultrasound imaging. To address this shortcoming, we have explored a grounds-up re-evaluation of the way in which ultrasound can be used in neurosonography based on the hypothesis that backscattered signal from the intracranial space can be analyzed to identify the unique signature of pooling and coagulated blood. Preliminary experiments with tissue phantoms, ex vivo animal blood, and ex vivo human calvaria have established the parameters that optimize the SNR of pulse-echo transc...

Pre- and postdesiccation sound speeds through ex vivo porcine skull specimens were determined by time-of-flight measurements with propagated broadband pulses centered at 0.97 MHz (Phis12.7 mm, -6-dB bandwidth = 58%). The measured longitudinal sound speed in the 13 porcine samples (predesiccation average sound speed = 1727 plusmn 57 ms-1) changed by a statistically significant +2.3% after deionized water reconstitution (paired t-test, alpha = 0.05, p = 0.0332).

At a previous meeting (June 1995) a report was given on anomalous behavior of the Rayleigh–Ritz method for calculating the normal mode frequencies of elastic solids (the method that forms the basis for most resonant ultrasound work), when those solids had the shapes of slightly perturbed parallelepipeds. These shapes are of interest to understand the effects of sample preparation errors on the overall elastic constant determination. In an effort to understand these effects, a systematic study of the various interrelated computational issues in RUS has been undertaken. Attempts are made to address the following issues: (1) whether the anomalous behavior of the Rayleigh‐Ritz solutions is algorithmic or numerical; (2) whether these anomalies may result from problems with the inverse calculation (where the frequencies are inverted to obtain elastic constants) as well; and (3) what relationship exists between the RMS error in the frequencies and the confidence in the elastic constant determination. Results wil...

The development and growth of rye (Secale cereale L. cv. Rheidol) was studied in seedlings grown hydroponically in complete nutrient solutions containing between 10 and 600 μM K+. The phyllochron (defined as the interval between the appearance of successive leaves) was used as a developmental timescale to compare plants. The pattern of both shoot and root development was strictly ordered on a phyllochron basis and was unaffected by solution K+ concentration, with the exception that tillers in plants grown at the lowest K+ concentrations were occasionally either not initiated or aborted at an early stage of development. However, both the rate of leaf appearance on the main stem and successive tillers and the rate of tiller appearance were slower in plants grown at lower K+ concentrations. The rate of leaf appearance on the main stem was reduced to below 90% of its maximal value at solution concentrations below about 50 μM K+. Plant relative growth rate (RGR) was also reduced by lowering the K+ concentration of the nutrient solution and fell to below 90% of its maximal value at solution concentrations below about 200 μM K+. There was a complex relationship between tissue K+ concentration and the K+ concentration of the nutrient solution, which differed between leaves and root. Leaf K+ concentration increased steadily from about 50 μmol g-1 f. wt to about 200 μmol g-1 f. wt as solution K+ concentration was increased from 10 to 400 μM. In contrast, root K+ concentration exhibited a sigmoidal dependence on solution K+ concentration, maintaining a minimal value of approximately 20 μmol g-1 f. wt at concentration below 100 μM K+, then increasing progressively to about 120 μmol g-1 f. wt at a solution concentration of 600 μM K+. The 'critical' leaf K+ concentration, i.e. the concentration at which either plant RGR or plant development was reduced 90% of its maximal value, was 86 μmol g-1 f. wt for plant RGR and 150 μmol g-1 f. wt for plant development. The 'critical' root K+ concentration was 24 μmol g-1 f. wt K+ for both RGR and development. A decline in tissue K+ concentration below these thresholds reduced plant growth considerably. Root K+ concentration was a sensitive indicator of the K+ status of the plant with respect to potential growth since plant growth declined abruptly as root K+ concentration approached its 'critical' value, whereas plant growth showed a less defined relationship with shoot K+ concentration.

One of the most, basic trade-offs in ultrasound imaging involves frame rate, depth, and number of lines. Achieving good spatial resolution and coverage requires a large number of lines, leading to decreases in frame rate. An even more serious imaging challenge occurs with imaging modes involving spatial compounding and 3-D/4-D imaging, which are severely limited by the slow speed of sound in tissue. The present work can overcome these traditional limitations, making ultrasound imaging many-fold faster. By emitting several beams at once, and by separating the resulting overlapped signals through spatial and temporal processing, spatial resolution and/or coverage can be increased by many-fold while leaving frame rates unaffected. The proposed approach can also be extended to imaging strategies that do not involve transmit beamforming, such as synthetic aperture imaging. Simulated and experimental results are presented where imaging speed is improved by up to 32-fold, with little impact on image quality. Object complexity has little impact on the method’s performance, and data from biological systems can readily be handled. The present work may open the door to novel multiplexed and/or multidimensional protocols considered impractical today.

Slime isolated after growth of four strains of coagulase-negative staphylococci on chemically defined medium plus agar was rich in galactose. However, when sterile agar plates were extracted with saline, high-molecular-weight material with similar properties was obtained that also was galactose-rich. Most of the dry weight attributed to slime, and probably all the galactose, originated from agar. Slime isolated by gel and ion-exchange chromatography from liquid culture in the same medium contained glycerol phosphate, glucose (no galactose), glucosamine, alanine, uronate, an unidentified component, and protein. Separation of protein from carbohydrate was achieved by affinity chromatography. [14C]glucose in the medium labeled the carbohydrate polymer; [14C]amino acids chiefly labeled extracellular proteins. Slime from bacteria grown on medium solidified with silica gel or on dialysis membrane above an agar surface showed essentially the same composition and behavior after purification as the material isolated from liquid culture.

Higher frequency components, which are induced by a nonlinear response of tissue under high pressures, have long been known to enhance thermal ablation due to the increased absorption of the higher frequencies. It has been proposed that aspects of nonlinear propagation could be used to control power deposition. This study describes an approach designed to exploit the enhanced heating effect of nonlinear ultrasound while utilizing yet another property of a properly designed nonlinear field. By using a relatively low driving frequency to propagate through aberration layers close to the source before the buildup of higher harmonics, the less distorted low frequency wave then acts as a virtual source, creating a higher frequency beam of harmonics of the driving source. Simulation and experimental studies have established the feasibility of the proposed method. The results identify parameters that exhibit reduced spatial distortion of HIFU focal fields when the 2nd harmonic is analyzed. This was shown to be the case for both single-source and multiple-source focused ultrasound, and experimentally demonstrated with ultrasound transmission through both bone phantom and ex vivo human skull. In a highly inhomogeneous nearfield, as may be created by bone or fat layers, the resulting field is considerably less distorted than direct linear propagation of the same frequency. Future challenges include the optimization of this effect by designing a beam that minimizes the fundamental frequency and maximizes the harmonics at the target.

Most operational protocols for HIFU procedures do not incorporate a pre-treatment planning stage comparable to the rigorous pre-treatment planning that is mandated for other modalities of radiation therapy. Ongoing studies investigating pre-treatment strategies that would improve the efficiency and effectiveness of HIFU treatments are complex in nature. Most are based on the incorporation of predictive phase-aberration corrections of propagation-path-specific phase changes. We have shown that the substantially simpler method of optimizing HIFU source placement in relation to layered tissue structures can have a significant effect on focal integrity, and that MRI scans and a wave-vector time-domain linear propagation model can potentially be used to plan for optimized source orientation. Five ex vivo bovine tissue specimens with heterogeneous tissue structures were each mounted in rigid frames with acoustic windows for HIFU transmission. A spherically-focused HIFU source (F0 = 1.502 MHz, D = 100 mm, Rc = 100 mm) was positioned to transmit though each specimen at pre-selected orientations, and the transmitted ultrasound pressure fields were scanned for a series of orientations, followed by a series of MRI scans. Ultrasound transmission simulations were performed and compared with experimental results. Analyses performed on the acoustic field scans to quantify the level of focal distortion [distortion index (DI) = 1- (the ratio between the acoustic energy within a focal zone and the total acoustic energy within the measured area] demonstrated that over the 5 specimens, at least an average of 7.3% (range 5.6% to 12.3%, SD = 2.8%) improvement in DI could be expected by source placement optimization. The accurate simulation of ultrasound propagation through heterogeneous tissue layers using MRI data was also achieved.

A device that uses the shear mode of transcranial ultrasound transmission for intraoperative monitoring has been designed, constructed, and tested with 10 human subjects. Magnetic resonance (MR) images were obtained with the device spatially registered to the MR reference coordinates. Peaks in both the ultrasound and MR signals were identified and analyzed both for spatial localization and signal-to-noise ratio (SNR). The first results aimed towards validating the prototype device against MRI have demonstrated excellent correlation (n = 38, R2 = 0.9962) between the structural localization abilities of the two modalities. In addition, the overall SNR of the ultrasound backscatter signals (n = 38, SNR = 25.4plusmn5.2 dB) was statistically equivalent to that of the MR data (n = 38, SNR = 22.5plusmn4.8 dB).

Theme The conservation of bison (Bison bison) in Yellowstone National Park from near extinction to a high of 5000 animals has led to societal conflict regarding overabundance and potential transmission of brucellosis to cattle with widespread economic consequences. As abundance increased during 1971–1996, more bison migrated from the Hayden and Pelican valleys to the lower-elevation Madison headwaters area and, eventually, outside the park (Meagher 1998, Fuller et al. 2007). Meagher (1998) and others (Taper et al. 2000, Gates et al. 2005) concluded these migratory movements were stress-related responses to decreased food availability as bison fully occupied habitat in the Pelican and Hayden valleys and, subsequently, the Firehole and Madison river drainages. This hypothesis implies that these areas have a relatively fixed capacity for wintering bison and, as a result, a larger proportion of bison migrate to the Madison headwaters and elsewhere as bison numbers increase beyond this capacity. However, density-independent factors such as genetic predisposition, individual asymmetries (e.g., age, sex), and stochastic variations in climate that influence food availability may also affect migration (Lundberg 1987). We used data collected during 1970–1971 through 2005–2006 to quantify annual variations in the magnitude and timing of migration by central herd bison, identify potential factors driving this variation, and evaluate if the proportion of migrants increased with abundance.

Traditional ultrasound imaging methods rely on the bandwidth and center frequency of transduction to achieve axial and radial image resolution, respectively. In this study, a new modality for spatially localizing scattering targets in a two-dimensional field is presented. In this method, the bandwidth of field excitation is high, and the center frequency is lowered such that the corresponding wavelengths are substantially larger than the target profiles. Furthermore, full two-dimensional field measurements are obtained with single send-receive sequences, demonstrating a substantial simplification of the traditional scanning techniques. Field reconstruction is based on temporal-spectral cross-correlations between measured backscatter data and a library of region of interest (ROI) backscatter data measured a priori. The transducer design is based upon a wedge-shaped geometry, which was shown to yield spatially frequency-separated bandwidths of up to 156% with center frequencies of 1.38 MHz. Initial results with these send-and-receive transducer parameters and cylindrical reflection targets in a 10-mm times 10-mm ROI demonstrate two-dimensional target localization to within 0.5 mm. Spatial localization of point scatterers is demonstrated for single and multiple scattering sites.

The development of large-aperture multiple-source transducer arrays for ultrasound transmission through the human skull has demonstrated the possibility of controlled and substantial acoustic energy delivery into the brain parenchyma without the necessitation of a craniotomy. The individual control of acoustic parameters from each ultrasound source allows for the correction of distortions arising from transmission through the skull bone and also opens up the possibility for electronic steering of the acoustic focus within the brain. In addition, the capability to adjust the frequency of insonation at different locations on the skull can have an effect on ultrasound transmission. To determine the efficacy and applicability of a multiple-frequency approach with such a device, this study examined the frequency dependence of ultrasound transmission in the range of 0.6–1.4 MHz through a series of seventeen points on four ex vivo human skulls. Effects beyond those that are characteristic of frequency-dependent attenuation were examined. Using broadband pulses, it was shown that the reflected spectra from the skull revealed information regarding ultrasound transmission at specific frequencies. A multiple-frequency insonation with optimized frequencies over the entirety of five skull specimens was found to yield on average a temporally brief 230% increase in the transmitted intensity with an 88% decrease in time-averaged intensity transmission within the focal volume. This finding demonstrates a potential applicability of a multiple-frequency approach in transcranial ultrasound transmission.

The behavior of a 1–3 piezocomposite transducer at high driving amplitudes and off‐resonance frequencies was investigated numerically and experimentally. By heuristically generating a numerical model of a simple resonator with a hard restoring force, a likely mechanism was identified for harmonic distortions in high power ultrasound transduction. Experimental observations of enhanced upper harmonic content in transducer response to a sinusoidal driving function were analyzed. This analysis revealed that a substantial proportion of the total pressure amplitude (at least 51%) was distributed into harmonics of the driving frequency, especially at frequencies that were below or above a characteristic resonance peak of the transducer. These results imply a need for more detailed and thorough evaluation of ultrasound transducers which are designed for high‐intensity applications.

Although the transmission of ultrasound (US) through the skull bone has been demonstrated for both therapeutic and imaging applications, the clinical efficacy of certain transcranial US applications remains limited by the highly attenuating properties of skull bone. For those applications, the ability to pre-procedurally determine those areas of the skull that are less attenuating to US could be a tremendous asset for improving the use of US in the brain. To present a possible solution, we have hypothesized that the optical transmission intensity at points across the skull surface can be correlated with the local US transmission efficiency. The demonstration of this correlation would potentially allow for the use of integrated lasers and photodetectors within a HIFU system to create a patient-specific transmission map of the skull. We have statistically investigated the relationship between transmitted optical and US intensities over multiple points across several ex vivo human calvaria to demonstrate this correlation. Along with the results of the analysis, preliminary designs to incorporate optical transmission assessment in transcranial HIFU and echoencephalography will be presented.

The present state-of-the-art technology in clinical neurosonography requires an acoustic window to achieve a sufficient signal-to-noise ratio (SNR) for detection of intracranial hemorrhage (ICrH). Conventional clinical practices use ultrasound in the range of 2–10 MHz to image and diagnose patients, a frequency range that is too high to produce high-quality transcranial images. This study examined the use of ultrasound frequencies on the order of 0.5 MHz, applied through the skull bone, to detect ICrH. We demonstrated with exvivo human skull specimens, ex vivo animal blood, and soft tissue-mimicking phantoms that a single element ultrasonic transducer can likely be used to detect the presence of ICrH immediately adjacent to the skull bone. The lower frequency design of the transducer together with optimized aperture geometry demonstrated efficient signal transmission through the skull bone with a focal depth optimized for intracranial anatomy. The identification of hemorrhage-brain interfaces was demonstr...