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1.
Sensors (Basel) ; 24(7)2024 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-38610538

RESUMEN

Safe autonomous vehicle (AV) operations depend on an accurate perception of the driving environment, which necessitates the use of a variety of sensors. Computational algorithms must then process all of this sensor data, which typically results in a high on-vehicle computational load. For example, existing lane markings are designed for human drivers, can fade over time, and can be contradictory in construction zones, which require specialized sensing and computational processing in an AV. But, this standard process can be avoided if the lane information is simply transmitted directly to the AV. High definition maps and road side units (RSUs) can be used for direct data transmission to the AV, but can be prohibitively expensive to establish and maintain. Additionally, to ensure robust and safe AV operations, more redundancy is beneficial. A cost-effective and passive solution is essential to address this need effectively. In this research, we propose a new infrastructure information source (IIS), chip-enabled raised pavement markers (CERPMs), which provide environmental data to the AV while also decreasing the AV compute load and the associated increase in vehicle energy use. CERPMs are installed in place of traditional ubiquitous raised pavement markers along road lane lines to transmit geospatial information along with the speed limit using long range wide area network (LoRaWAN) protocol directly to nearby vehicles. This information is then compared to the Mobileye commercial off-the-shelf traditional system that uses computer vision processing of lane markings. Our perception subsystem processes the raw data from both CEPRMs and Mobileye to generate a viable path required for a lane centering (LC) application. To evaluate the detection performance of both systems, we consider three test routes with varying conditions. Our results show that the Mobileye system failed to detect lane markings when the road curvature exceeded ±0.016 m-1. For the steep curvature test scenario, it could only detect lane markings on both sides of the road for just 6.7% of the given test route. On the other hand, the CERPMs transmit the programmed geospatial information to the perception subsystem on the vehicle to generate a reference trajectory required for vehicle control. The CERPMs successfully generated the reference trajectory for vehicle control in all test scenarios. Moreover, the CERPMs can be detected up to 340 m from the vehicle's position. Our overall conclusion is that CERPM technology is viable and that it has the potential to address the operational robustness and energy efficiency concerns plaguing the current generation of AVs.

2.
South Med J ; 117(1): 11-15, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-38151245

RESUMEN

OBJECTIVES: Thoracic outlet syndrome (TOS) is an uncommon neurovascular disorder that presents as neck and upper extremity pain secondary to brachial plexus trunk or subclavian vasculature compression. The orthopedic literature has correlated patient-reported allergies to postoperative patient-reported outcome (PRO) scores for a variety of surgical procedures. We sought to evaluate patient-reported allergies and PROs following surgical decompression for TOS. METHODS: A chart review was conducted after identifying patients who underwent surgical thoracic outlet decompression by a single surgeon. Patients were contacted and administered five PRO questionnaires via telephone: the QuickDASH Outcome Measure questionnaire (disabilities of the arm, shoulder, and hand [DASH]), the Cervical Brachial Symptom Questionnaire, the Single Assessment Numeric Evaluation, the 12-Item Short Form Survey, and the Numeric Rating Scale (a visual analogue scale). A bivariate analysis of Pearson's correlation coefficient (r) was used to determine the associations of allergies with questionnaires and demographic variables. RESULTS: Of the 393 patients (128 males and 265 females) identified in the study, 75 (24%) responded and completed all of the questionnaires, 18 (24%) males and 57 (76%) females. A significant correlation was found between the number of allergies reported and the QuickDASH Outcome Measure questionnaire (r = 0.375, P < 0.001), the Cervical Brachial Symptom Questionnaire (r = 0.295, P = 0.01), change in the Single Assessment Numeric Evaluation score (r = -0.310, P < 0.01), change in the visual analogue scale (r = 0.244, P = 0.035), sex (r = 0.245, P = 0.034), and the number of medications (r = 0.642, P < 0.001). CONCLUSIONS: The increased frequency of patient-reported allergies is significantly associated with worse PRO scores for women undergoing TOS surgical decompression. Better understanding this association can help physicians counsel patients on expected outcomes.


Asunto(s)
Hipersensibilidad , Síndrome del Desfiladero Torácico , Masculino , Humanos , Femenino , Autoinforme , Resultado del Tratamiento , Síndrome del Desfiladero Torácico/complicaciones , Síndrome del Desfiladero Torácico/epidemiología , Síndrome del Desfiladero Torácico/cirugía , Encuestas y Cuestionarios , Descompresión Quirúrgica/métodos , Hipersensibilidad/complicaciones , Hipersensibilidad/epidemiología , Hipersensibilidad/cirugía , Estudios Retrospectivos
3.
Meat Sci ; 201: 109192, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37084549

RESUMEN

This study compared the fatty acid and mineral concentrations of lamb meat that was prepared to different levels of cooking doneness. Ten m. longissimus lumborum were each sectioned into 4 slices that were randomly assigned to be uncooked or grilled to an internal end-point temperature of 60 °C (rare), 71 °C (medium), or 77 °C (well done). It was found that cooking loss increased as the level of cooking doneness increased. The proportion of most major fatty acids were not altered by cooking. However, when adjusted for cooking loss (i.e., mg/135 g serve of lamb as-is equivalent prepared to each level of cooking doneness), the concentration of most major fatty acids, including C16:0, C18:0, C18:1n-9, and many conjugated linoleic acids, were lowered after grilling to any level of cooking doneness and compared to the uncooked samples. The omega-6 to omega-3 ratio was lowest for the uncooked samples and highest for those prepared to a well done level of cooking doneness. Conversely, the concentration of health claimable omega-3 fatty acids in the uncooked meat was retained upon cooking and across all the different internal endpoint temperatures. Calcium, magnesium, phosphorous, potassium, and sodium were reduced with preparation of lamb meat to any level of cooking doneness, compared with uncooked meat. Zinc, iron, and selenium were retained within the cooked samples. These findings show that consumer preference for a level of cooking doneness will have only minor effects on the concentration of minerals and fatty acids in lamb meat.


Asunto(s)
Carne Roja , Selenio , Ovinos , Animales , Temperatura , Ácidos Grasos , Carne Roja/análisis , Culinaria , Carne/análisis
4.
Sensors (Basel) ; 22(16)2022 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-36015761

RESUMEN

Commercialization of autonomous vehicle technology is a major goal of the automotive industry, thus research in this space is rapidly expanding across the world. However, despite this high level of research activity, literature detailing a straightforward and cost-effective approach to the development of an AV research platform is sparse. To address this need, we present the methodology and results regarding the AV instrumentation and controls of a 2019 Kia Niro which was developed for a local AV pilot program. This platform includes a drive-by-wire actuation kit, Aptiv electronically scanning radar, stereo camera, MobilEye computer vision system, LiDAR, inertial measurement unit, two global positioning system receivers to provide heading information, and an in-vehicle computer for driving environment perception and path planning. Robotic Operating System software is used as the system middleware between the instruments and the autonomous application algorithms. After selection, installation, and integration of these components, our results show successful utilization of all sensors, drive-by-wire functionality, a total additional power* consumption of 242.8 Watts (*Typical), and an overall cost of $118,189 USD, which is a significant saving compared to other commercially available systems with similar functionality. This vehicle continues to serve as our primary AV research and development platform.


Asunto(s)
Conducción de Automóvil , Vehículos Autónomos , Inteligencia Artificial , Conservación de los Recursos Energéticos , Análisis Costo-Beneficio
5.
Hand (N Y) ; 17(1): 43-49, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-32036706

RESUMEN

Background: Although the diagnosis of thoracic outlet syndrome (TOS) is often missed, outcomes from surgical intervention significantly improve patient satisfaction. This article seeks to highlight patient characteristics, intraoperative findings, and both short and long-term outcomes of thoracic outlet decompression in the adolescent population. Methods: A retrospective chart review of patients between the ages of 13 and 21 years with a clinical diagnosis of neurogenic thoracic outlet syndrome (NTOS) who were treated surgically between 2000 and 2015 was performed. Data points including preoperative patient characteristics and intraoperative findings were collected. In addition, patient-reported outcome scores, including Visual Analog Scale (VAS), Single Assessment Numeric Evaluation (SANE), Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire, Cervical Brachial Symptom Questionnaire (CBSQ), and NTOS index, were obtained for a cohort of patients with follow-up ranging from 2 to 15 years. Results: The study population consisted of 54 patients involving 61 extremities. The most common procedures included neurolysis of the supraclavicular brachial plexus (60, 98.4%), anterior scalenectomy (59, 96.7%), and middle scalenectomy (54, 88.5%). First rib resection (FRR) was performed in 28 patients (45.9%). Long-term outcomes were collected for 24 (44%) of 54 patients with an average follow-up of 69.5 months (range, 24-180 months). The average VAS improved from 7.5 preoperatively to 1.8 postoperatively. The average SANE increased from 28.9 preoperatively to 85.4 postoperatively. The average postoperative scores were 11.4 for the QuickDASH, 27.4 for the CBSQ, and 17.2 for the NTOS index. Subgroup analysis of patients having FRR (28, 45.9%) demonstrated no difference in clinical outcome measures compared with patients who did not have FRR. Conclusion: Surgical treatment of NTOS in adolescent patients has favorable intermediate and long-term outcomes.


Asunto(s)
Síndrome del Desfiladero Torácico , Adolescente , Adulto , Descompresión Quirúrgica/métodos , Humanos , Estudios Retrospectivos , Costillas/cirugía , Síndrome del Desfiladero Torácico/cirugía , Resultado del Tratamiento , Adulto Joven
6.
Med Eng Phys ; 83: 142-147, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32507417

RESUMEN

This note describes the development of a mixed-reality assistive robotic wheel chair simulator for testing of Parkinson's tremor mitigation and operator assistance. It consists of a power chair (PCh), roller dynamometer, head mounted virtual reality (VR) display, computer with VR game engine, and microcontroller to interface the PCh and computer. Unlike past VR PCh simulators, both a tremor notch filter and basic collision avoidance is implemented. Further, the simulator identifies the Parkinson's tremor frequency. Operator performance is assessed using deviations from a given route and velocity profile. To demonstrate the simulator's operation, an operator with Parkinson's tremor drove the PCh down two 20 m long hallways connected by a 90∘ turn while operating data was collected. Results show less variation in velocity tracking with use of the notch filter than without it; route tracking was nearly the same. Advantages of the simulator compared to a wholly physical approach are low cost, improved safety, portability, small footprint, and environments and robotic features are virtual.


Asunto(s)
Enfermedad de Parkinson , Procedimientos Quirúrgicos Robotizados , Robótica , Realidad Virtual , Simulación por Computador , Humanos , Enfermedad de Parkinson/diagnóstico , Temblor/diagnóstico , Interfaz Usuario-Computador
7.
J Vasc Surg ; 72(3): 790-798, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32497747

RESUMEN

The global SARS-CoV-2/COVID-19 pandemic has required a reduction in nonemergency treatment for a variety of disorders. This report summarizes conclusions of an international multidisciplinary consensus group assembled to address evaluation and treatment of patients with thoracic outlet syndrome (TOS), a group of conditions characterized by extrinsic compression of the neurovascular structures serving the upper extremity. The following recommendations were developed in relation to the three defined types of TOS (neurogenic, venous, and arterial) and three phases of pandemic response (preparatory, urgent with limited resources, and emergency with complete diversion of resources). • In-person evaluation and treatment for neurogenic TOS (interventional or surgical) are generally postponed during all pandemic phases, with telephone/telemedicine visits and at-home physical therapy exercises recommended when feasible. • Venous TOS presenting with acute upper extremity deep venous thrombosis (Paget-Schroetter syndrome) is managed primarily with anticoagulation, with percutaneous interventions for venous TOS (thrombolysis) considered in early phases (I and II) and surgical treatment delayed until pandemic conditions resolve. Catheter-based interventions may also be considered for selected patients with central subclavian vein obstruction and threatened hemodialysis access in all pandemic phases, with definitive surgical treatment postponed. • Evaluation and surgical treatment for arterial TOS should be reserved for limb-threatening situations, such as acute upper extremity ischemia or acute digital embolization, in all phases of pandemic response. In late pandemic phases, surgery should be restricted to thrombolysis or brachial artery thromboembolectomy, with more definitive treatment delayed until pandemic conditions resolve.


Asunto(s)
Betacoronavirus/patogenicidad , Infecciones por Coronavirus/prevención & control , Pandemias/prevención & control , Neumonía Viral/prevención & control , Guías de Práctica Clínica como Asunto , Síndrome del Desfiladero Torácico/diagnóstico , Triaje/normas , COVID-19 , Consenso , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/transmisión , Infecciones por Coronavirus/virología , Descompresión Quirúrgica/normas , Procedimientos Quirúrgicos Electivos/métodos , Procedimientos Quirúrgicos Electivos/normas , Tratamiento de Urgencia/métodos , Tratamiento de Urgencia/normas , Humanos , Control de Infecciones/normas , Comunicación Interdisciplinaria , Recuperación del Miembro/métodos , Recuperación del Miembro/normas , Selección de Paciente , Neumonía Viral/epidemiología , Neumonía Viral/transmisión , Neumonía Viral/virología , SARS-CoV-2 , Telemedicina/normas , Síndrome del Desfiladero Torácico/etiología , Síndrome del Desfiladero Torácico/terapia , Terapia Trombolítica/métodos , Terapia Trombolítica/normas , Tiempo de Tratamiento/normas
8.
JBJS Case Connect ; 9(3): e0392, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31584904

RESUMEN

CASE: We report 2 cases of brachial plexus injury after open subpectoral biceps tenodesis. In 1 patient, the nerves likely sustained a stretch injury related to retractor use. In the other patient, multiple nerves were severed, and we hypothesize that they were caught in a drill bit. CONCLUSIONS: To decrease the risk of nerve injury due to traction or inadvertent wrapping of nerves in the drill bit or tenodesis screw, we recommend careful retractor use and tendon fixation techniques that use a protective sleeve during both drilling and fixation.


Asunto(s)
Neuropatías del Plexo Braquial/etiología , Plexo Braquial/lesiones , Complicaciones Posoperatorias/etiología , Tenodesis/efectos adversos , Femenino , Humanos , Enfermedad Iatrogénica , Persona de Mediana Edad
9.
J Food Sci Technol ; 56(8): 3957-3961, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31413421

RESUMEN

This study compared the modified Soxhlet (Soxtec) and Folch extraction methods for determining the total lipid or intramuscular fat (IMF) content of aged beef samples. Ageing periods tested were 0, 5, 8, 10 and 12 weeks during which samples were held in vacuo and at ~ 1.0 °C. Prior to solvent extraction, all samples were freeze-dried and ground. The Folch method was found to result in higher IMF values and therefore higher extraction efficiency when compared to the Soxtec. A linear relationship was evident between the two methods that described 80.9% of the variation between IMF values. An interaction between ageing period and extraction method was identified, although ageing period did not independently impact on averaged IMF findings. Based on these observations and reagent toxicity not being a limiting factor, it is recommended that the Folch extraction method be used to determine beef IMF, although it is acknowledged that the Soxtec method IMF results were strongly aligned with those found using the Folch extraction method and tended towards comparability for beef aged < 5 weeks.

10.
Bioinformatics ; 35(11): 1978-1980, 2019 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-30376034

RESUMEN

SUMMARY: VarSome.com is a search engine, aggregator and impact analysis tool for human genetic variation and a community-driven project aiming at sharing global expertise on human variants. AVAILABILITY AND IMPLEMENTATION: VarSome is freely available at http://varsome.com. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Asunto(s)
Genoma Humano , Motor de Búsqueda , Programas Informáticos , Genómica , Humanos
11.
J Acoust Soc Am ; 146(6): 4224, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31893683

RESUMEN

Sonar systems that exploit correlation for navigation, such as correlation velocity logs and micronavigation for synthetic aperture sonar, often make redundant estimates of the spatial coherence of the scattered field at several spatial lags. Two models for the correlation of these redundant measurements are described. First, an analytical model is derived using the assumption of stationary Gaussian statistics. Next, a numerical model is described that accounts for non-stationary processes present in measurements of seafloor scattering. These models are compared to normal-incidence scattering data collected at Seneca Lake, NY. Both models show good agreement with the measurements when the spatial separation between redundant hydrophone pairs is less than the coherence length. At greater spatial separation, the analytical model diverges from the measurements. This disagreement is explained by a lack of stationarity in the measured data which is captured by the numerical model. Finally, spatial variations in the volume scattering strength of the sediment are identified as a source of the non-stationarity in the measurements.

13.
Meat Sci ; 121: 141-147, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27317848

RESUMEN

Primiparous Santa Gertrudis heifers were used to evaluate the effects of gestational dietary protein content on meat quality traits of 20month old bull progeny (n=40). At -60d before AI, heifers were randomly allocated to HIGH or LOW protein diet (HPERI and LPERI). From 24dpc, half of each treatment group changed to an alternative post-conception HIGH or LOW protein diet (HPOST and LPOST). LPERI and LPOST diets resulted in higher shear force of the semitendinosus muscle than HPERI (P=0.053) and HPOST (P=0.003), respectively. Heat-soluble collagen in the semitendinosus muscle was lower (P=0.019) for LPERI than HPERI. Collagen and tenderness of the longissimus muscle were not affected by dam nutrition (P>0.05). Color, pH, sarcomere length, cooking loss, compression values, desmin and troponin-T degradation, fiber type, intramuscular fat and polyunsaturated fatty acid content were not affected by dam nutrition during the peri-conception and first trimester gestational period (P>0.05).


Asunto(s)
Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Dieta/veterinaria , Proteínas en la Dieta/administración & dosificación , Preñez , Carne Roja/análisis , Tejido Adiposo/química , Animales , Bovinos , Colágeno/química , Color , Culinaria , Desmina/metabolismo , Grasas de la Dieta/análisis , Ácidos Grasos Insaturados/análisis , Femenino , Calidad de los Alimentos , Concentración de Iones de Hidrógeno , Masculino , Carne , Proteínas Musculares/química , Músculo Esquelético/química , Fenotipo , Embarazo , Sarcómeros/química , Troponina T/metabolismo
14.
Rev Urol ; 18(1): 28-32, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27162509

RESUMEN

Falls and fractures have a significant impact on our patients, their families, and caregivers, and cost the health care system billions of dollars. Each year, millions of adults aged 65 and older fall. Falls can cause moderate to severe injuries, such as hip fractures and head traumas, and can increase the risk of early death. Fortunately, falls are a public health problem that is largely preventable. Because many patients with falls and subsequent fractures have urologic conditions, urologists are positioned to help with the prevention of these significant and costly injuries. This article discusses the epidemiology of falls and fractures, and the urologic comorbidities that increase their risk.

15.
Biomech Model Mechanobiol ; 15(6): 1713-1731, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27169403

RESUMEN

While cardiovascular device-induced thrombosis is associated with negative patient outcomes, the convoluted nature of the processes resulting in a thrombus makes the full thrombotic network too computationally expensive to simulate in the complex geometries and flow fields associated with devices. A macroscopic, continuum computational model is developed based on a simplified network, which includes terms for platelet activation (chemical and mechanical) and thrombus deposition and growth in regions of low wall shear stress (WSS). Laminar simulations are performed in a two-dimensional asymmetric sudden expansion geometry and compared with in vitro thrombus size data collected using whole bovine blood. Additionally, the predictive power of the model is tested in a flow cell containing a series of symmetric sudden expansions and contractions. Thrombi form in the low WSS area downstream of the asymmetric expansion and grow into the nearby recirculation region, and thrombus height and length largely remain within 95 % confidence intervals calculated from the in vitro data for 30 min of blood flow. After 30 min, predicted thrombus height and length are 0.94 and 4.32 (normalized by the 2.5 mm step height). Importantly, the model also correctly predicts locations of thrombus deposition observed in the in vitro flow cell of expansions and contractions. As the simulation results, which rely on a greatly reduced model of the thrombotic network, are still able to capture the macroscopic behavior of the full network, the model shows promise for timely predictions of device-induced thrombosis toward optimizing and expediting the device development process.


Asunto(s)
Corazón Auxiliar/efectos adversos , Modelos Cardiovasculares , Trombosis/etiología , Trombosis/patología , Animales , Velocidad del Flujo Sanguíneo , Bovinos , Simulación por Computador , Activación Plaquetaria , Reproducibilidad de los Resultados , Estrés Mecánico , Factores de Tiempo
16.
J Bacteriol ; 197(20): 3245-54, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26381189

RESUMEN

UNLABELLED: The plasmid R1162 (RSF1010) encodes a primase essential for its replication. This primase makes up the C-terminal part of MobA, a multifunctional protein with the relaxase as a separate N-terminal domain. The primase is also translated separately as the protein RepB'. Here, we map two signals for type IV secretion onto the recently solved structure of RepB'. One signal is located internally within RepB' and consists of a long α-helix and an adjacent disordered region rich in arginines. The second signal is made up of the same α-helix and a second, arginine-rich region at the C-terminal end of the protein. Successive arginine-to-alanine substitutions revealed that either signal can be utilized by the type IV secretion complex of the plasmid R751. The internal signal also enables conjugal transfer when linked to the relaxase part of MobA. Both signals are similar to those previously identified for type IV secretion substrates in the Vir system of Agrobacterium tumefaciens. Moreover, the C-terminal arginine-rich segment of RepB' has been shown to be secreted by Vir. However, with R751, the signals require MobB, an R1162-encoded accessory protein active in conjugal transfer. The results of two-hybrid assays revealed that MobB interacts, via its membrane-associated domain, with the R751 plasmid coupling protein TraG. In addition, MobB interacts with a region of MobA just outside the RepB' domain. Therefore, MobB is likely an adaptor that is essential for recognition of the primase-associated signals by the R751 secretion machinery. IMPORTANCE: For most plasmids, type IV secretion is an intrinsic part of the mechanism for conjugal transfer. Protein relaxases, bound to the 5' end of the transferring strand, are mobilized into recipient cells by the type IV pathway. In this work, we identify and characterize two signals for secretion in the primase domain of MobA, the relaxase of the IncQ plasmid R1162 (RSF1010). We also show that the adaptor protein MobB is required for engagement of these signals with the R751 coupling protein TraG. These results clarify the location and properties of secretion signals active during the conjugal transfer of plasmid DNA.


Asunto(s)
ADN Primasa/metabolismo , Escherichia coli K12/metabolismo , Plásmidos/fisiología , Sistemas de Secreción Tipo IV/fisiología , Secuencia de Aminoácidos , Clonación Molecular , ADN Primasa/genética , ADN Bacteriano , Escherichia coli K12/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Datos de Secuencia Molecular , Conformación Proteica , Transducción de Señal
17.
Nat Commun ; 5: 4122, 2014 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-24947823

RESUMEN

In primates, C-fibre polymodal nociceptors are broadly classified into two groups based on mechanosensitivity. Here we demonstrate that mechanically sensitive polymodal nociceptors that respond either quickly (QC) or slowly (SC) to a heat stimulus differ in responses to a mild burn, heat sensitization, conductive properties and chemosensitivity. Superficially applied capsaicin and intradermal injection of ß-alanine, an MrgprD agonist, excite vigorously all QCs. Only 40% of SCs respond to ß-alanine, and their response is only half that of QCs. Mechanically insensitive C-fibres (C-MIAs) are ß-alanine insensitive but vigorously respond to capsaicin and histamine with distinct discharge patterns. Calcium imaging reveals that ß-alanine and histamine activate distinct populations of capsaicin-responsive neurons in primate dorsal root ganglion. We suggest that histamine itch and capsaicin pain are peripherally encoded in C-MIAs, and that primate polymodal nociceptive afferents form three functionally distinct subpopulations with ß-alanine responsive QC fibres likely corresponding to murine MrgprD-expressing, non-peptidergic nociceptive afferents.


Asunto(s)
Potenciales de Acción/fisiología , Ganglios Espinales/citología , Calor , Fibras Nerviosas Amielínicas/fisiología , Nociceptores/clasificación , Nociceptores/fisiología , Animales , Capsaicina/farmacología , Ganglios Espinales/efectos de los fármacos , Histamina/farmacología , Inyecciones Intradérmicas , Macaca , Masculino , Nociceptores/efectos de los fármacos , Estimulación Física , Estadísticas no Paramétricas , Estimulación Química , beta-Alanina/administración & dosificación , beta-Alanina/farmacología
18.
J Biomech Eng ; 136(7)2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24805351

RESUMEN

Thrombosis and thromboembolization remain large obstacles in the design of cardiovascular devices. In this study, the temporal behavior of thrombus size within a backward-facing step (BFS) model is investigated, as this geometry can mimic the flow separation which has been found to contribute to thrombosis in cardiac devices. Magnetic resonance imaging (MRI) is used to quantify thrombus size and collect topographic data of thrombi formed by circulating bovine blood through a BFS model for times ranging between 10 and 90 min at a constant upstream Reynolds number of 490. Thrombus height, length, exposed surface area, and volume are measured, and asymptotic behavior is observed for each as the blood circulation time is increased. Velocity patterns near, and wall shear stress (WSS) distributions on, the exposed thrombus surfaces are calculated using computational fluid dynamics (CFD). Both the mean and maximum WSS on the exposed thrombus surfaces are much more dependent on thrombus topography than thrombus size, and the best predictors for asymptotic thrombus length and volume are the reattachment length and volume of reversed flow, respectively, from the region of separated flow downstream of the BFS.


Asunto(s)
Simulación por Computador , Hidrodinámica , Imagen por Resonancia Magnética , Resistencia al Corte , Estrés Mecánico , Trombosis/fisiopatología , Animales , Circulación Sanguínea , Bovinos , Modelos Biológicos , Trombosis/patología , Factores de Tiempo
19.
J Acoust Soc Am ; 135(1): 155-64, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24437755

RESUMEN

Tonpilz acoustic transducers for use underwater often include a stack of piezoelectric material pieces polarized along the length of the stack and having alternating polarity. The pieces are interspersed with electrodes, bonded together, and electrically connected in parallel. The stack is normally much shorter than a quarter wavelength at the fundamental resonance frequency so that the mechanical behavior of the transducer is not affected by the segmentation. When the transducer bandwidth is less than a half octave, as has conventionally been the case, for example, with lead zirconate titanate (PZT) material, stack segmentation has no significant effect on the mechanical behavior of the device in its normal operating band near the fundamental resonance. However, when a high coupling coefficient material such as lead magnesium niobate-lead titanate (PMN-PT) is used to achieve a wider bandwidth with the tonpilz, the performance difference between a segmented stack and a similar piezoelectric section with electrodes only at the two ends can be significant. This paper investigates the effects of stack segmentation on the performance of wideband underwater tonpilz acoustic transducers. Included is a discussion of a particular tonpilz transducer design using single crystal piezoelectric material with high coupling coefficient compared with a similar design using more traditional PZT ceramics.

20.
Anesthesiology ; 119(2): 422-32, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23880991

RESUMEN

BACKGROUND: Spinal cord stimulation (SCS) is a useful neuromodulatory technique for treatment of certain neuropathic pain conditions. However, the optimal stimulation parameters remain unclear. METHODS: In rats after L5 spinal nerve ligation, the authors compared the inhibitory effects on mechanical hypersensitivity from bipolar SCS of different intensities (20, 40, and 80% motor threshold) and frequencies (50, 1 kHz, and 10 kHz). The authors then compared the effects of 1 and 50 Hz dorsal column stimulation at high- and low-stimulus intensities on conduction properties of afferent Aα/ß-fibers and spinal wide-dynamic-range neuronal excitability. RESULTS: Three consecutive daily SCS at different frequencies progressively inhibited mechanical hypersensitivity in an intensity-dependent manner. At 80% motor threshold, the ipsilateral paw withdrawal threshold (% preinjury) increased significantly from pre-SCS measures, beginning with the first day of SCS at the frequencies of 1 kHz (50.2 ± 5.7% from 23.9 ± 2.6%, n = 19, mean ± SEM) and 10 kHz (50.8 ± 4.4% from 27.9 ± 2.3%, n = 17), whereas it was significantly increased beginning on the second day in the 50 Hz group (38.9 ± 4.6% from 23.8 ± 2.1%, n = 17). At high intensity, both 1 and 50 Hz dorsal column stimulation reduced Aα/ß-compound action potential size recorded at the sciatic nerve, but only 1 kHz stimulation was partially effective at the lower intensity. The number of actions potentials in C-fiber component of wide-dynamic-range neuronal response to windup-inducing stimulation was significantly decreased after 50 Hz (147.4 ± 23.6 from 228.1 ± 39.0, n = 13), but not 1 kHz (n = 15), dorsal column stimulation. CONCLUSIONS: Kilohertz SCS attenuated mechanical hypersensitivity in a time course and amplitude that differed from conventional 50 Hz SCS, and may involve different peripheral and spinal segmental mechanisms.


Asunto(s)
Neuralgia/terapia , Estimulación de la Médula Espinal/métodos , Médula Espinal/fisiopatología , Animales , Modelos Animales de Enfermedad , Masculino , Dimensión del Dolor/métodos , Umbral del Dolor , Ratas , Ratas Sprague-Dawley
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