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PURPOSE The objective of this study was to investigate the presence of nonbladder sensory abnormalities in participants with overactive bladder syndrome (OAB). MATERIALS AND METHODS Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN) study participants with OAB symptoms and controls were recruited from 6 U.S. tertiary referral centers. Quantitative sensory testing (QST) was performed to determine pressure pain sensitivity at the thumbnail bed and auditory sensitivity. Fixed and mixed effect multivariable linear regressions and Weibull models were used to compare QST responses between groups. Pearson correlations were used to assess the relationship between QST measures. Associations between QST and self-reported symptoms were explored with linear regression. RESULTS A total of 297 participants were analyzed (191 OAB, 106 controls; 76% white, 51% male). OAB cases were older than controls (57.4 vs 52.2 years, p=0.015). No significant differences in experimental thumbnail (nonbladder) pain or auditory sensitivity were detected between OAB cases and controls. Correlations between pressure and auditory derived metrics were weak to moderate overall for both groups, with some significantly stronger correlations for cases. Exploratory analyses indicated increased pressure pain and auditory sensitivity were modestly associated with greater self-reported bladder pain and pain interference with physical function. CONCLUSIONS As a group, no significant differences between OAB cases and controls were observed in experimental nonbladder pain or auditory sensitivity during QST. Associations between QST outcomes and clinical pain raise the possibility of centrally mediated sensory amplification in some individuals with OAB.

Objectives Quantitative sensory testing may help predict treatment responses in individuals with chronic pain. Our objective was to determine whether evoked pain sensitivity at baseline predicted preferential treatment responses to either emotional awareness and expression therapy (EAET) or cognitive behavioral therapy (CBT) in individuals with fibromyalgia (FM). Methods This was a secondary analysis of a previous randomized clinical trial, in which individuals with FM were randomized to EAET, CBT, or Education as a control intervention. Only females who completed baseline and post-treatment assessments were analyzed (n=196). The primary outcome was change in overall clinical pain severity from pretreatment to posttreatment, and the primary predictor of interest was pressure pain tolerance at baseline. Results Among patients with low pain tolerance at baseline (n=154), both EAET and CBT led to small but significant improvements in clinical pain severity (CBT mean=0.66, 95% confidence interval [0.24-1.07]; EAET mean=0.76 [0.34-1.17]). Conversely, in patients with normal pain tolerance (n=42), there was no significant improvement in clinical pain after CBT (0.13 [-0.88 to 1.14]), a small improvement after FM Education (0.81 [0.14-1.48]), but a much larger and statistically significant improvement after EAET (2.14 [1.23-3.04]). Discussion Normal levels of pressure pain tolerance at baseline predicted greater improvement in clinical pain severity after EAET than CBT. Quantitative sensory testing may provide insights about individual responses to psychologically based therapies for individuals with chronic pain.

INTRODUCTION AND OBJECTIVE:It has been hypothesized that some overactive bladder (OAB) patients may have central sensitization and/or increased sensitivity to sensory stimuli (“sensory/afferent hyp...

Background Persistent cancer-related fatigue is one of the most common and burdensome symptoms experienced by ovarian cancer survivors. Despite the high burden of fatigue in ovarian cancer survivors, there are few available treatments. Previous research has shown self-acupressure to be a safe method for improving persistent fatigue, sleep, and quality of life among fatigued breast cancer survivors, yet there are no studies examining self-acupressure for fatigue in ovarian cancer survivors. Methods A three group parallel, randomized controlled trial will be conducted to evaluate the efficacy of self-acupressure taught and delivered via a patient-designed, custom-built mobile app ("MeTime") and accompanying hand-held device ("AcuWand") to help guide correct pressure application. A sample of 165 ovarian cancer survivors, who have completed primary cancer treatment will be recruited from tumor registries in Michigan and Los Angeles. Participants will be mailed a tablet preloaded with the app and a device, and all visits will be conducted remotely. Participants will be randomized to 6-weeks of daily self-acupressure via the app and device, or a sham app and device, or no care group. Self-report measures will be completed at baseline, 6-weeks (post-intervention), 3-, and 6-months. Primary outcome is the Brief Fatigue Inventory; secondary outcomes are sleep, quality of life, and symptoms commonly associated with persistent fatigue. Discussion An app based self-acupressure treatment may be an easily-accessible and inexpensive treatment to reduce fatigue in ovarian cancer survivors. The results of the study will provide information on the possible benefits of app-based self-acupressure for fatigue in ovarian cancer survivors. Trial registration: This study is registered at ClinicalTrials.gov Identifier: NCT03763838, date registered on December 4, 2018.

Experimental pain sensitivity was assessed in individuals with urologic chronic pelvic pain syndrome (UCPPS) as part of the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network. A series of computer-controlled pressure stimuli were delivered to the thumbnail bed, an asymptomatic site distant from the area of UCPPS pain that is considered to be indicative of overall body pain threshold. Stimuli were rated according to a standardized magnitude estimation protocol. Pain sensitivity in participants with UCPPS was compared with healthy controls and a mixed pain group composed of individuals with other chronic overlapping pain conditions, including fibromyalgia, chronic fatigue, and irritable bowel syndromes. Data from 6 participating MAPP testing sites were pooled for analysis. Participants with UCPPS (n = 153) exhibited an intermediate pain sensitivity phenotype: they were less sensitive relative to the mixed pain group (n = 35) but significantly more sensitive than healthy controls (n = 100). Increased pain sensitivity in patients with UCPPS was associated with both higher levels of clinical pain severity and more painful body areas outside the pelvic region. Exploratory analyses in participants with UCPPS revealed that pain sensitivity increased during periods of urologic symptom flare and that less pressure pain sensitivity at baseline was associated with a greater likelihood of subsequent genitourinary pain improvement 1 year later. The finding that individuals with UCPPS demonstrate nonpelvic pain hypersensitivity that is related to clinical symptoms suggests that central nervous system mechanisms of pain amplification contribute to UCPPS.

Dentists regularly employ a variety of self‐report and sensory techniques to aid in the diagnosis and treatment of tooth‐related disease. Many of these techniques leverage principles borrowed from psychophysics, the quantitative measurement of the relationship between stimuli and evoked sensations, which falls under the larger umbrella of quantitative sensory testing (QST). However, most clinicians fail to meet the bar for what could be considered quantitative sensory testing, and instead focus on qualitative and dichotomous “yes/no” aspects of sensory experience. With our current subjective measurements for pain assessments, diagnosis and treatment of dental pain in young children and individuals (any age) with severe cognitive impairment rely extensively on third‐party observations. Consequently, the limitation of inadequate pain diagnosis can lead to poor pain management. In this review, it discusses mechanisms that underlie acute and chronic dental pain. It details the measurement of somatosensory responses and pulpal blood flow as objective measures of tooth health and pain. It proposes that bridging these varied methodologies will significantly improve diagnosis and treatment of orofacial pain and pathology. It concludes that improving the precision of sensory measurements could yield important improvements in diagnostic challenges in pulpal pathology for noncommunicative and cognitively impaired individuals.

The American Society of Anesthesiologists Standards for Basic Monitoring recommends blood pressure (BP) measurement every 5 min. Research has shown distractions or technical factors can cause prolonged measurement intervals exceeding 5 min. We investigated the relationship between prolonged non-invasive BP (NIBP) measurement interval and the incidence of hypotension, detected postinterval. Our secondary outcome was to determine independent predictors of these prolonged NIBP measurement intervals. Retrospective data were analyzed from 139,509 general anesthesia cases from our institution’s Anesthesia Information Management System (AIMS). Absolute hypotension (AH) was defined a priori as a systolic BP < 80 mmHg and relative hypotension (RH) was defined as a 40% decrease in systolic BP from the preoperative baseline. Odds ratios (OR) with 95% confidence intervals and Pearson’s Chi square Test reported the association of prolonged NIBP measurement intervals on hypotension detected post-NIBP measurement interval. Logistic regression models were developed to determine independent predictors of NIBP measurement intervals. The analysis revealed that NIBP measurement intervals greater than 6 and 10 min are associated with an approximately four times higher incidence of a patient transitioning into hypotension (AH/RH > 6 min OR 4.0 / 3.6; AH/RH > 10 min OR 4.3 / 3.9; p< 0.001). A key finding was that the “> 10-minute AH model” indicated that age 41–80, increased co-morbidity profile, obesity and turning (repositioning) of the operative room table were significant predictors of prolonged NIBP measurement intervals (p < 0.001). While we do not suggest NIBP measurement intervals cause hypotension, intervals greater than 6 and 10 min are associated with a fourfold increase in the propensity of an undetected transition into both RH or AH. These data support current monitoring guidelines.

To review the scientific literature pertaining to the use of hand-carried and hand-held ultrasound devices in low- and middle-income countries (LMIC), with a focus on clinical applications, geographical areas of use, the impact on patient management and technical features of the devices used.; The electronic databases PubMed and Google Scholar were searched. No language or date restrictions were applied. Case reports and original research describing the use of hand-carried ultrasound devices in LMIC were included if agreed upon as relevant by two-reviewer consensus based on our predefined research questions.; A total of 644 articles were found and screened, and 36 manuscripts were included for final review. Twenty-seven studies were original research articles, and nine were case reports. Several reports describe the successful diagnosis and management of difficult, often life-threatening conditions, using hand-carried and hand-held ultrasound. These portable ultrasound devices have also been studied for cardiac screening exams, as well as a rapid triage tool in rural areas and after natural disaster. Most applications focus on obstetrical and abdominal complaints. Portable ultrasound may have an impact on clinical management in up to 70% of all cases. However, no randomised controlled trials have evaluated the impact of ultrasound-guided diagnosis and treatment in resource-constrained settings. The exclusion of articles published in journals not listed in the large databases may have biased our results. Our findings are limited by the lack of higher quality evidence (e.g. controlled trials).; Hand-carried and hand-held ultrasound is successfully being used to triage, diagnose and treat patients with a variety of complaints in LMIC. However, the quality of the current evidence is low. There is an urgent need to perform larger clinical trials assessing the impact of hand-carried ultrasound in LMIC.

Analgesic trials frequently fail to demonstrate efficacy of drugs known to be efficacious. Poor pain reporting accuracy is a possible source for this low essay-sensitivity. We report the effects of Accurate-Pain-Reporting-Training (APRT) on the placebo response in a trial of Pregabalin for painful-diabetic-neuropathy. The study was a two-stage randomized, double-blind trial: In Stage-1 (Training) subjects were randomized to APRT or No-Training. The APRT participants received feedback on the accuracy of their pain reports in response to mechanical stimuli, measured by R-square score. In Stage-2 (Evaluation) all subjects entered a placebo-controlled, cross-over trial. Primary (24-h average pain intensity) and secondary (current, 24-h worst, and 24-h walking pain intensity) outcome measures were reported. Fifty-one participants completed the study. APRT patients (n = 28) demonstrated significant (p = 0.036) increases in R-square scores. The APRT group demonstrated significantly (p = 0.018) lower placebo response (0.29 ± 1.21 vs. 1.48 ± 2.21, mean difference ± SD = -1.19±1.73). No relationships were found between the R-square scores and changes in pain intensity in the treatment arm. In summary, our training successfully increased pain reporting accuracy and resulted in a diminished placebo response. Theoretical and practical implications are discussed.

A syringe-implantable electrocardiography (ECG) monitoring system is proposed. The noise optimization and circuit techniques in the analog front-end (AFE) enable 31 nA current consumption while a minimum energy computation approach in the digital back-end reduces digital energy consumption by 40%. The proposed SoC is fabricated in 65 nm CMOS and consumes 64 nW while successfully detecting atrial fibrillation arrhythmia and storing the irregular waveform in memory in experiments using an ECG simulator, a live sheep, and an isolated sheep heart.

Friction stir forming utilizes a friction stirring action to soften and extrude a base material into a cavity in a substrate material thereby forming a joint. In this research, Abaqus software was used to model the process in order to understand the key joint features of interest and provide direction for experimental optimization. A three dimensional, thermo-mechanical finite element model was developed and applied to simulate the process and obtain detailed stress and temperature distribution plots. Adaptive mesh and contact features were utilized for large deformation of the aluminum work material. It was found that the model accurately predicted the shape of the joint and flash extrusion during the process. The maximum temperature was found at the outer radius of the tool, but was much lower than temperatures in friction stir welding.

This study measures the vascular wall shear rate at the vessel edge using decorrelation based ultrasound speckle tracking. Results for nine healthy and eight renal disease subjects are presented. Additionally, the vascular wall shear rate and circumferential strain during physiologic pressure, pressure equalization and hyperemia are compared for five healthy and three renal disease subjects. The mean and maximum wall shear rates were measured during the cardiac cycle at the top and bottom wall edges. The healthy subjects had significantly higher mean and maximum vascular wall shear rate than the renal disease subjects. The key findings of this research were that the mean vascular wall shear rates and circumferential strain changes between physiologic pressure and hyperemia that was significantly different between healthy and renal disease subjects.

The effect of process parameters (cycle time, tool speed and axial force) on the specimen temperature measured 2 mm away from the weld in spot friction welding (SFW) of Al 6111-T4 is investigated. The temperatures were correlated to the lap shear load. Results revealed that, to achieve a good joint strength with the maximum lap shear load >2˙5 kN, temperatures should be greater than a threshold value, which is 350°C at a location close to the SFW joint in this study. By studying the specimen macrographs, two internal weld geometric features based on the cross-section area were identified and correlated to the shear and mixed failure modes of the lap shear tested specimens. A model was developed and validated using experimental data of the cross section area of SFW joint with either shear or mixed mode fracture. The model predicts that the SFW joint strength is maximised at the transition region between the shear and mixed mode fracture.

Friction stir welding (FSW) is a solid state joining technique that is rapidly establishing itself as an approved production technique and it remains the focus of significant international research effort. Scientific understanding of the FSW process is necessary for its successful automation. The interaction between the rotating tool and the alloy is complex, making the determination of the contribution of various process parameters (tool geometry, temperature, rake angle, speed and feed) to the desired weld properties difficult. The construction of a rotating multi-axial transducer has been realised. This allows online and offline measurement of process responses (force footprint, energy, temperature, etc.) and can be incorporated into a feedback control system for the processes technical and economic trade-off regulation. This paper describes the design, development and calibration of this multi-axial transducer. The application of the real-time process data to develop the force footprint as an aid for gaining scientific insight into FSW is also discussed.

Introduction: Home telemetry monitoring with accurate automated rhythm classification can have important clinical benefits in the timely diagnosis and appropriate management of patients with atrial fibrillation (AF). We clinically validated a novel personal e-Health device and algorithm developed to distinguish AF from sinus rhythm (SR). Methods: A handheld electrocardiogram (ECG) recording system (Maestro) and signal processing platform were developed. The Maestro provides an LCD interface that continuously shows an ECG, heart rate, and heart rhythm status. Twenty second ECG signals analogous to Lead I were acquired from 66 patients presenting to the arrhythmia clinic at the University of Michigan Hospital either in SR or AF. Electrograms were segmented into non-overlapping 6-second samples and one random segment per patient was selected for analysis by the Maestro system. Simultaneous 5 or 12 lead ECGs were obtained from these patients and 3 expert physicians blinded to the Maestro analysis identified the rhythm as SR or AF. The Maestro system applied several signal conditioning algorithms to each ECG sample. The dimensionless temporal R-R interval variability (VRR) index and spectral frequency dispersion metric (FDM) were computed. Results: The 2-dimensional scatter-gram of the samples demonstrated 2 distinct clusters of VRR and FDM for patients with SR and AF. The VRR index clusters for SR and AF patients were 0.018 ± 0.013 and 0.187 ± 0.073 (mean±std), respectively (p < 0.001). The FDM clusters for SR and AF patients occurred at 10.5 ± 5.916 and 15.892 ± 3.337, respectively (p < 0.001). We developed a Gaussian Mixed Model (GMM) classifier to distinguish between the AF and SR clusters. Only after the GMM classifier was obtained were the Maestro classifications compared to the physicians’ readings. The algorithm correctly categorized AF (N = 46) and SR (N = 20) for all Maestro segments analyzed with 100% specificity and sensitivity. Conclusion: The Maestro handheld telemetry unit utilizes a novel classification algorithm and was demonstrated to acquire and automatically analyze 6-second electrograms for rapid and accurate classification of patients in SR or AF in this initial clinical validation trial.

This paper investigates the self-learning of inverse kinematics for the feed-forward control of a robot to position intracardiac catheters. Cardiac ablation is routinely performed to treat Atrial Fibrillation, and requires a catheter be accurately positioned in the heart, by hand or by a robot, under feedback control. This is typically a slow process and methods to reduce procedure times are needed. To investigate our proposed method, a robotic system to manipulate a standard intracardiac catheter was constructed. To safely develop our proposed learning system, a comprehensive dataset was collected using a magnetic tracking system to measure the catheter tip positions versus robot actuator positions. Initially, the robot began with no model of its kinematics. A Genetic Algorithm was used to decide on the next actuator sequence that would reduce the uncertainty in a Feedforward Neural Network (FFNN) based inverse kinematic model. An automated iterative process was followed where the robot would perform virtual experiments, to grow its knowledge of its inverse kinematics. After 791 learning cycles the final analysis revealed that the complete inverse kinematic relationship has been explored with the given constraints. A validation dataset indicated the learned FFNN model was able to predict x, y and z positions of the catheter tip to within ±0.17 mm, ±0.73 mm and ±0.62 mm, respectively. The robot successfully self-learned its inverse kinematic model using the proposed methodology. Future work is required to investigate the influence of disturbances on positioning accuracy.

Management of fluid overload in patients with end-stage renal disease represents a unique challenge to clinical practice because of the lack of accurate and objective measurement methods. Currently, peripheral edema is subjectively assessed by palpation of the patient's extremities, ostensibly a qualitative indication of tissue viscoelastic properties. New robust quantitative estimates of tissue fluid content would allow clinicians to better guide treatment, minimizing reactive treatment decision making. Ultrasound viscoelastography (UVE) can be used to estimate strain in viscoelastic tissue, deriving material properties that can help guide treatment. We are developing and testing a simple, low-cost UVE system using a single-element imaging transducer that is simpler and less computationally demanding than array-based systems. This benchtop validation study tested the feasibility of using the UVE system by measuring the mechanical properties of a tissue-mimicking material under large strains. We generated depth-dependent creep curves and viscoelastic parameter maps of time constants and elastic moduli for the Kelvin model of viscoelasticity. During testing, the UVE system performed well, with mean UVE-measured strain matching standard mechanical testing with maximum absolute errors ≤4%. Motion tracking revealed high correlation and signal-to-noise ratios, indicating that the system is reliable.

There has been significant work on the application of ultrahigh strength steels and aluminum alloys for automotive body mass reduction. Integration of these materials into the automotive structure is non-trivial and advanced methods are required to effectively join the dissimilar materials with the properties required for automotive applications. Friction stir forming is a new environmentally benign manufacturing process for joining dissimilar materials. Fundamentally this process is based on frictional heating and mechanically stirring a plasticized material into a mechanical interlocking joint with a second material. In this research, the significant process parameters were identified and their optimized settings for the current experimental conditions defined using a design of experiments methodology. The overall joint structure and grain microstructure were mapped along different stages of the friction stir forming process. Then, friction stir forming of aluminum work material into different cavity geometries was mapped to study geometrical effects. Two layers were found to form within the aluminum, the thermo-mechanical affected zone that had been deformed due to the contact pressure and angular momentum of the tool, and the heat affected deformation zone that deformed into the interlocking cavity. The geometrical study produced interesting results about the direction and magnitude of material forming under different areas of the tool.

Friction Stir Welding (FSW) is a modern, solid-state joining processes, involving frictional heating and mechanical forging. High quality joints can be created using a control system that compensates for external disturbances by regulating the state of the weld zone (WZ) surrounding the tool. However, in this situation direct monitoring is complex since the rotating tool is embedded in plasticized material. This research discusses the development of a Bluetooth-based Wireless Rotating Process Monitoring (WRPM) system to overcome limitations in inductive/capacitive telemetry systems. Communication channel performance was assessed to determine the suitability of Bluetooth for use in the feedback control loop for in-process FSW WZ temperature control. Peak round-trip communications latencies of 300–650 ms for 20–200 byte payloads were observed. Additionally, electrical noise from the machine tool reduced the receive signal strength measured on the Bluetooth module. The bit error rate (BER) also increased from 0 to 0.001 % as spindle speed increased from 0 to 1400 rpm. Due to the communication latency, the signal strength and BER effects were not observed to affect throughput. The results support the use of the WRPM system for feedback control of FSW. However, deterministic communication latency must be achieved to enable the design of a stable control system.

Bioimpedance spectroscopy (BIS) has shown significant potential in many areas of medicine to provide new physiologic markers. Several acute and chronic diseases are accompanied by changes in intra- and extracellular fluid within various areas of the human body. The estimation of fluid in various body compartments is therefore a simple and convenient method to monitor certain disease states. In this work, the design and evaluation of a BIS instrument are presented and three key areas of the development process investigated facilitating the BIS measurement of tissue hydration state. First, the benefit of incorporating DC-stabilizing circuitry to the standard modified Howland current pump (MHCP) is investigated to minimize the effect of DC offsets limiting the dynamic range of the system. Second, the influence of the distance between the bioimpedance probe and a high impedance material is investigated using finite element analysis (FEA). Third, an analytic compensation technique is presented to minimize the influence of parasitic capacitance. Finally, the overall experimental setup is evaluated through ex vivo BIS measurements of porcine spleen tissue and compared to published results. The DC-stabilizing circuit demonstrated its ability to maintain DC offsets at less than 650 μV through 100 kHz while maintaining an output impedance of 1 MΩ from 100 Hz to 100 kHz. The proximity of a bioimpedance probe to a high impedance material such as acrylic was shown to increase measured impedance readings by a factor of 4x as the ratio of the distance between the sensing electrodes to the distance between the bioimpedance probe and acrylic reached 1:3. The average parasitic capacitance for the circuit presented was found to be 712 ± 128 pF, and the analytic compensation method was shown to be able to minimize this effect on the BIS measurements. Measurements of porcine spleen tissue showed close correlation with experimental results reported in published articles. This research presents the successful design and evaluation of a BIS instrument. Specifically, robust measurements were obtained by implementing a DC-stabilized current source, investigating probe-material proximity issues and compensating for parasitic capacitance. These strategies were shown to provide tissue measurements comparable with published literature.

We present an 8-bit sub-ranging SAR ADC designed for bursty signals having long time periods with small code spread. A modified capacitive-DAC (CDAC) saves previous sample’s MSB voltage and reuses it throughout subsequent conversions. This prevents unnecessary switching of large MSB capacitors as well as conversion cycles, reducing energy consumed in the comparator and digital logic and yielding total energy savings of 2.6×. In 0.18μm CMOS, the ADC consumes 120nW at 0.6V and 100kS/s with 46.9dB SNDR.

Background/Aims: Recently, ultrasound signals termed ‘lung water comets' associated with pulmonary edema have been correlated with adverse clinical events in dialysis patients. These comets fluctuate substantially during the ultrasound exam highlighting the need for objective quantitative measurement methods. Methods: We developed an image-processing algorithm for the detection and quantification of lung comets. Quantification measures included comet number (comet count) and the fraction of the ultrasound beams with comet findings (comet fraction). We used this algorithm in a pilot study in 20 stable dialysis outpatients to identify associations between ultrasound comets and clinical parameters including blood pressure (BP), percent blood volume reduction on dialysis (%BV), ejection fraction (EF), and ultrafiltration on dialysis (UF). Results: Positive findings included associations with lung comet measurements with pre-dialysis Diastolic BP (r = 0.534, p = 0.015), subject age (r = -0.446, p = 0.049), and a combination of EF and end dialysis %BV reduction (r = -0.585, p = 0.028). Comet fraction and comet count were closely correlated due to the inherent relationship between these two metrics (r = 0.973, p < 0.001). Negative findings included ultrasound comets that did not change from beginning to end of dialysis (p = 0.756), and were not significantly correlated with single dialysis treatment UF (p = 0.522), subject body weight (p = 0.208), or BMI (p = 0.358). Conclusions: Ultrasound signal processing methods may help quantify lung ultrasound comets. Additional findings include algorithmic lung comet measurement that did not change significantly during single dialysis sessions in these stable outpatients, but were associated with cardiovascular and fluid status parameters.

Electrocardiography (ECG) is a critical source of information for a number of heart disorders. In arrhythmia studies and treatment, long-term observation is critical to determine the nature of the abnormality and its severity. However, even small body-wearable systems can impact a patient's everyday life and signals captured using such systems are prone to noise from sources such as 60Hz power and body movement. In contrast, implanted devices are less susceptible to these noise sources and, while having closer-spaced electrodes, can obtain similar quality ECG signals due to their proximity to the heart [1]. In addition, implanted devices enable continuous monitoring without affecting patient quality of life. As in other implantable systems, low power consumption is a critical factor; in this case to provide a sufficiently long operating time between wireless recharge events.

This study investigated the use of ultrasound speckle decorrelation- and correlation-based lateral speckle-tracking methods for transverse and longitudinal blood velocity profile measurement, respectively. By studying the blood velocity gradient at the vessel wall, vascular wall shear stress, which is important in vascular physiology as well as the pathophysiologic mechanisms of vascular diseases, can be obtained. Decorrelation-based blood velocity profile measurement transverse to the flow direction is a novel approach, which provides advantages for vascular wall shear stress measurement over longitudinal blood velocity measurement methods. Blood flow velocity profiles are obtained from measurements of frame-to-frame decorrelation. In this research, both decorrelation and lateral speckle-tracking flow estimation methods were compared with Poiseuille theory over physiologic flows ranging from 50 to 1000 mm/s. The decorrelation flow velocity measurement method demonstrated more accurate prediction of the flow velocity gradient at the wall edge than the correlation-based lateral speckle-tracking method. The novelty of this study is that speckle decorrelation-based flow velocity measurements determine the blood velocity across a vessel. In addition, speckle decorrelation-based flow velocity measurements have higher axial spatial resolution than Doppler ultrasound measurements to enable more accurate measurement of blood velocity near a vessel wall and determine the physiologically important wall shear.

Vascular access (VA) surveillance to guide care is essential for dialysis patients. Non-linear, patient specific formation of stenoses reduce VA efficiency. Various methods are used to monitor blood flow or pressure. However, these are surrogates for stenosis rather than direct measurements. There is also no reimbursement for VA surveillance and measurements consume clinician time, making more frequent measurements difficult. Hemodynamic variability increases the chance of infrequent observations missing stenosis formation. This paper presents a specialized ultrasound system intended to slide between the dialysis needles and provide operator independent VA geometry and volume flow during treatment. Specific attention is paid toward the magnetic design of the Lorentz force linear actuator. Experimental results indicate that the system can successfully collect Doppler flow information across a tissue-mimicking flow phantom vessel.

Ultrasound transducer arrays represent the current standard for medical ultrasound imaging applications. Despite this, the development of low-cost imaging systems is typically limited to single element wobbler transducers. We have developed a novel single element transducer system that is able to replicate the function of expensive linear arrays. This system uses a Lorentz force linear motor to mechanically sweep a single element transducer along a linear path. In order to optimize our system's operating characteristics for high speed imaging applications, we have performed a fluid dynamics analysis of the drag generated as a result of the transducer motion. Analytical and finite element models are derived for the motion of a rectangular cylinder through a confined channel. Our analysis reveals that small changes to the actuator housing geometry can drastically reduce drag, allowing us to achieve higher imaging frame rates. In addition, we predict the formation of an alternating vortex street that may introduce an additional source of vibration.

Renal disease is epidemic in the United States with 8 × 106 people having chronic kidney disease (CKD) with a glomerular filtration rate of less than 60 ml/min and another 12 × 106 having evidence of microalbuminuria. Bleeding from biopsy is a major problem in many areas of medicine but particularly in nephrology where the risk of serious bleeding from the kidney, although infrequent, may become life threatening [1–4]. Risk factors associated with bleeding such as hypertension or other comorbidities have been studied [2,3]. However, while methods of performing kidney biopsies have improved over the last two decades, renal biopsies still entail inherent bleeding risk such that approximately a third may have postbiopsy hematoma [1,2]. Even though some modifiable risk factors are mitigated, most patients at increased risk are not biopsied. Even mild coagulopathies increase the risk such that conventional (percutaneous) renal biopsy is contraindicated [1,3,4]. While these and other published data indicate that serious bleeding complications occur in only 1%–2% of cases, the data are inherently biased by excluding the riskiest patients from percutaneous renal biopsy. Because of this bleeding risk, renal biopsy is used sparingly in the CKD population, ranging in western countries from 3.3 in 100,000 in Italy, to 21.5 in 100,000 in Australia [5]. While accurate biopsy rates in the US are lacking, using a median rate of 16.2 in 100,000 such as that reported for France [5], yields an estimate of approximately 50,000 renal biopsies annually in the US. The contraindication of biopsy is not optimal since the risk of bleeding is greater in many patient populations where renal biopsy would be most helpful, such as in autoimmune diseases and renal dysfunction manifested by elevated creatinine greater than 2 mg/dl [4]. Even though most hematoma do not become life threatening, the current strategy for monitoring and managing complications can be improved. Safer renal biopsy will allow more accurate diagnosis and better management of this epidemic health problem. Prior attempts at designing biopsy needles that deploy hemostatic agents have been made [6–9]. However, there are two shortcomings in prior designs. First, they attempt to deploy an unshielded hemostatic plug into the kidney (or other organ) tissue along the outside of the biopsy needle shaft during the biopsy procedure. These plugs will be met with resistance from the remaining organ tissue as it is introduced into the biopsy site, resulting in ineffective deployment. Second, no controlled deployment mechanism has been developed that will reliably fill the tissue void created by the biopsy needle with the hemostatic plug. Other designers have attempted to improve guidance and deployment mechanisms in standard two-stage biopsy needles [10–15], but these prior solutions do not address the problem of effective deployment of the hemostatic plug within the void as the needle is withdrawn. While there are a variety of approaches that may be taken to improve the current situation, we have chosen to develop a biopsy needle and mechanism that injects a hemostatic plug at the time of biopsy to control bleeding. This study evaluates the performance of a prototype biopsy device referred to as the therapeutic injection system (TIS). The TIS is designed to minimize the risk of bleeding complications by delivering a shielded hemostatic plug using a specialized delivery mechanism. The clotting and sealing caused by the plug material then completes the hemostatic action. The following two sections describe the design and validation of this device. Section 4 provides experimental results, followed by Secs. 5 and 6 presenting a discussion of the results and concluding remarks.

Quantitative evaluation of tissue hydration and edema is a key marker to guide clinical care. Towards this end, a pulsed-wave (PW) tissue Doppler device to directly measure time-dependent tissue deformation (strain and strain rate) is being developed. With integrated bio-impedance (BIZ) measurements, this system has the potential to significantly improve the edema assessments currently being used. The current study acquires depth dependent tissue creep Doppler signals which are fitted to a linear viscoelastic model to obtain time constants suitable for assessing edema. In addition BIZ measurements were performed looking forward to sensor integration. Work continues to advance the determination of viscoelastic tissue properties, targeting the prototype development for clinical studies.

Quantitative sensory testing (QST) can provide useful information about the underlying mechanisms involved in chronic pain. However, currently available devices typically employed suffer from operator-dependent effects, or are too cumbersome for routine clinical care. This paper presents the design and initial validation of a novel automated pressure-pain type QST platform, termed the multi-modal automated sensory testing (MAST) system. The MAST configuration presented consists of wireless, hand-held thumbnail pressure stimulators (with circular 10 mm2 rubber tips) and graphical touch screen interface devices to manage the QST process and obtain patient feedback. Validation testing of the custom-designed force sensor showed a 1 % error for low forces increasing to 2 % error for larger loads up to 100 N (full-scale). Validation of the controller using three ramp rates (64, 248, and 496 kPa/s) and six pressures (32, 62, 124, 273, 620, and 1116 kPa) showed an overall mean error of 1.7 % for applied stimuli. Clinical evaluation revealed decreased pressure pain thresholds in chronic pain patients (98.07 ± SE 16.34 kPa) compared to pain free, healthy control subjects (259.88 ± SE 33.54 kPa, p = 0.001). The MAST system is portable and produces accurate, repeatable stimulation profiles indicating potential for point-of-care applications.

Intelligent medical displays have the potential to improve patient outcomes by integrating multiple physiologic signals, exhibiting high sensitivity and specificity, and reducing information overload for physicians. Research findings have suggested that information overload and distractions caused by patient care activities and alarms generated by multiple monitors in acute care situations, such as the operating room and the intensive care unit, may produce situations that negatively impact the outcomes of patients under anesthesia. This can be attributed to shortcomings of human-in-the-loop monitoring and the poor specificity of existing physiologic alarms. Modern artificial intelligence techniques (ie, intelligent software agents) are demonstrating the potential to meet the challenges of next-generation patient monitoring and alerting.

In this study, metal particles were added during the spot friction welding (SFW) process, a solid state sheet metal joining process, to create a localized metal matrix composite (MMC) for the improvement of lap shear strength in AISI 6111-T4 aluminum alloy sheets. The Ancorsteel® 1000 particles were compressed between the upper and lower sheets and distributed concentrically around the tool axis perpendicular to the plate surface, which formed a localized MMC and were effective as the reinforcement particles in aluminum 6111-T4 alloy sheets. Results revealed that the MMC reinforcement improved the lap shear strength of SFW joints by about 25%. An aluminum-ferrous solid solution was formed around the steel particles along the aluminum matrix interface. The load-deflection curve shows that the steel particle MMC increased both the strength and ductility of SFW joint. This is attributed to two phenomena observed on the failed lap shear tensile specimens with SFW MMC. One is the longer and more torturous crack path, and the other is the secondary crack on steel particle MMC reinforced SFW joints.

BACKGROUND: Anterior retraction of the tongue is used to enhance upper airway patency during pediatric fiberoptic intubation. This can be achieved by the use of Magill forceps as a tongue retractor, but lingual grip can become unsteady and traumatic. Our objective was to modify this instrument using computer-aided engineering for the purpose of stable tongue retraction. METHODS: We analyzed the geometry and mechanical properties of standard Magill forceps with a combination of analytical and empirical methods. This design was captured using computer-aided design techniques to obtain a 3-dimensional model allowing further geometric refinements and mathematical testing for rapid prototyping. RESULTS: On the basis of our experimental findings we adjusted the design constraints to optimize the device for tongue retraction. Stereolithography prototyping was used to create a partially functional plastic model to further assess the functional and ergonomic effectiveness of the design changes. To reduce pressure on the tongue by regular Magill forceps, we incorporated (1) a larger diameter tip for better lingual tissue pressure profile, (2) a ratchet to stabilize such pressure, and (3) a soft molded tip with roughened surface to improve grip. CONCLUSION: Computer-aided engineering can be used to redesign and prototype a popular instrument used in airway management. On a computational model, our modified Magill forceps demonstrated stable retraction forces, while maintaining the original geometry and versatility. Its application in humans and utility during pediatric fiberoptic intubation are yet to be studied.

There is a lack in understanding of the frictional contact condition during friction stir processes. High temperature, force and work material adhesion to and from the tool make the coefficient of friction difficult to measure. In this study, an experiment was set up to simultaneously measure the temperature and normal and frictional forces between a rotating tool and a stationary workpiece at steady state conditions. The coefficient of friction was measured for increasing temperature. A simple model was created to convert the thermocouple temperature measurement to the temperature at the point of contact between the tool and workpiece. It was found that the coefficient of friction had a decreasing trend as temperature approached the solidus temperature of the work material. The results and analysis of the experiments are presented.Copyright © 2010 by ASME

Automated physiologic alarms are available in most commercial physiologic monitors. However, due to the variability of data coming from the physiologic sensors describing the state of patients, false positive alarms frequently occur. Each alarm requires review and documentation, which consumes clinicians' time, may reduce patient safety through 'alert fatigue' and makes automated physician paging infeasible. To address these issues a computerized architecture based on simple reactive intelligent agent technology has been developed and implemented in a live critical care unit to facilitate the investigation of deterministic algorithms for the improvement of the sensitivity and specificity of physiologic alarms. The initial proposed algorithm uses a combination of median filters and production rules to make decisions about what alarms to generate. The alarms are used to classify the state of patients and alerts can be easily viewed and distributed using standard network, SQL database and Internet technologies. To evaluate the proposed algorithm, a 28 day study was conducted in the University of Michigan Medical Center's 14 bed Cardiothoracic Intensive Care Unit. Alarms generated by patient monitors, the intelligent agent and alerts documented on patient flow sheets were compared. Significant improvements in the specificity of the physiologic alarms based on systolic and mean blood pressure was found on average to be 99% and 88% respectively. Even through significant improvements were noted based on this algorithm much work still needs to be done to ensure the sensitivity of alarms and methods to handle spurious sensor data due to patient or sensor movement and other influences.

This study investigates the application of metal particles in spot friction welding (SFW), a semi-solid state sheet metal joining process, to create the localized metal matrix composite (MMC) for the improvement of lap-shear strength. Ancorsteel® 1000 particles, compressed around the axial center-line of the tool between the upper and lower sheets, was demonstrated to form a localized MMC and effective as the reinforcement particles in aluminum 6111-T4 alloy sheets. Results revealed that the particle MMC in SFW increased the maximum lap-shear by 20%. In the stir-zone, steel particle sizes were significantly reduced due to breaking by mechanical action. Analysis revealed an aluminum-ferrous solid solution formation around the steel particle and aluminum matrix interfaces. In the heat-affected zone along the joint line, steel particles retained their original sizes and reinforced the joint interface. The load deflection curve and cross-section micrographs of the failed lap-shear tensile specimens indicated that, for steel particle MMC samples, the crack path was longer. This was due to a localized MMC forming along the joint interface and was identified as the primary factor responsible for the increase in SFW lap-shear strength.Copyright © 2009 by ASME

The friction stir welding (FSW) process requires advanced automation to ensure consistent and reliable joints. This has been realized by the development of an experimental set-up by the integration and online monitoring of accurate sensors with reliable modular control software. With increasing productivity and quality requirements imposed by manufacturers, machine flexibility and scalability are becoming increasingly pertinent. On-line process monitoring facilitates the `adaption' of machines able to respond to changing process parameters and conditions. Modular open software architectures allow flexibility in machine application. This paper introduces a fresh approach for the integration of the latest automation technology into an experimental setup equipped with an advanced sensory system. A new method of capturing sensory data and the implementation aspects of the software architecture for a micro-kernel based real-time embedded operating system is introduced. Agile automation of the FSW process is thus realized by advanced monitoring and control

Advanced process automation is essential to ensure consistent and reliable friction stir welds. This paper illustrates the potential for a better understanding of the influence of certain process parameters on weld properties, through their monitoring and feedback into process control during the welding process. To accomplish this, the force footprint and temperature profile need to be accurately monitored and controlled during welding. In particular, the reaction forces of the tool can be described through a “force footprint” and related to weld quality and dynamic performance. This requires the integration of reliable and accurate sensor output into a computerised control program. Such an instrumented friction stir welding (FSW) set-up has been created. These parameters include tool torque, tool temperature, vertical force of the tool shoulder on the material and the horizontal force profile around the tool during its revolution. Future work will include more complete determination of the temperature profile associated with the thermomechanically affected zone (TMAZ) weld region. The system monitors these parameters during welding and can modify tool speed, feed and forces in response to changing weld conditions.