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1.
Arterioscler Thromb Vasc Biol ; 32(9): 2214-22, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22772758

RESUMEN

OBJECTIVE: Bone morphogenetic proteins (Bmps) are important mediators of inflammation and atherosclerosis, though their mechanism of action is not fully understood. To better understand the contribution of the Bmp signaling pathway in vascular inflammation, we investigated the role of Bmper (Bmp endothelial cell precursor-derived regulator), an extracellular Bmp modulator, in an induced in vivo model of inflammation and atherosclerosis. METHODS AND RESULTS: We crossed apolipoprotein E-deficient (ApoE(-/-)) mice with mice missing 1 allele of Bmper (Bmper(+/-) mice used in the place of Bmper(-/-) mice that die at birth) and measured the development of atherosclerosis in mice fed a high-fat diet. Bmper haploinsufficiency in ApoE(-/-) mice (Bmper(+/-);ApoE(-/-) mice) led to a more severe phenotype compared with Bmper(+/+);ApoE(-/-) mice. Bmper(+/-);ApoE(-/-) mice also exhibited increased Bmp activity in the endothelial cells in both the greater and lesser curvatures of the aortic arch, suggesting a role for Bmper in regulating Bmp-mediated inflammation associated with laminar and oscillatory shear stress. Small interfering RNA knockdown of Bmper in human umbilical vein endothelial cells caused a dramatic increase in the inflammatory markers intracellular adhesion molecule 1 and vascular cell adhesion molecule 1 at rest and after exposure to oscillatory and laminar shear stress. CONCLUSIONS: We conclude that Bmper is a critical regulator of Bmp-mediated vascular inflammation and that the fine-tuning of Bmp and Bmper levels is essential in the maintenance of normal vascular homeostasis.


Asunto(s)
Enfermedades de la Aorta/prevención & control , Aterosclerosis/prevención & control , Proteínas Portadoras/metabolismo , Moléculas de Adhesión Celular/metabolismo , Células Endoteliales/metabolismo , Mediadores de Inflamación/metabolismo , Inflamación/prevención & control , Animales , Enfermedades de la Aorta/genética , Enfermedades de la Aorta/inmunología , Enfermedades de la Aorta/metabolismo , Enfermedades de la Aorta/patología , Apolipoproteínas E/deficiencia , Apolipoproteínas E/genética , Aterosclerosis/genética , Aterosclerosis/inmunología , Aterosclerosis/metabolismo , Aterosclerosis/patología , Proteína Morfogenética Ósea 4/metabolismo , Proteínas Portadoras/genética , Células Cultivadas , Modelos Animales de Enfermedad , Células Endoteliales/inmunología , Células Endoteliales/patología , Genotipo , Células Endoteliales de la Vena Umbilical Humana/inmunología , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Inflamación/genética , Inflamación/inmunología , Inflamación/metabolismo , Inflamación/patología , Molécula 1 de Adhesión Intercelular/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fenotipo , Interferencia de ARN , Proteínas Recombinantes/metabolismo , Estrés Mecánico , Factores de Tiempo , Transfección , Calcificación Vascular/inmunología , Calcificación Vascular/metabolismo , Calcificación Vascular/prevención & control , Molécula 1 de Adhesión Celular Vascular/metabolismo
2.
Sci Robot ; 7(67): eabl7755, 2022 06 29.
Artículo en Inglés | MEDLINE | ID: mdl-35767647

RESUMEN

Vision processing for control of agile autonomous robots requires low-latency computation, within a limited power and space budget. This is challenging for conventional computing hardware. Parallel processor arrays (PPAs) are a new class of vision sensor devices that exploit advances in semiconductor technology, embedding a processor within each pixel of the image sensor array. Sensed pixel data are processed on the focal plane, and only a small amount of relevant information is transmitted out of the vision sensor. This tight integration of sensing, processing, and memory within a massively parallel computing architecture leads to an interesting trade-off between high performance, low latency, low power, low cost, and versatility in a machine vision system. Here, we review the history of image sensing and processing hardware from the perspective of in-pixel computing and outline the key features of a state-of-the-art smart camera system based on a PPA device, through the description of the SCAMP-5 system. We describe several robotic applications for agile ground and aerial vehicles, demonstrating PPA sensing functionalities including high-speed odometry, target tracking, obstacle detection, and avoidance. In the conclusions, we provide some insight and perspective on the future development of PPA devices, including their application and benefits within agile, robust, adaptable, and lightweight robotics.


Asunto(s)
Robótica , Computadores , Visión Ocular , Percepción Visual
3.
IEEE Trans Pattern Anal Mach Intell ; 42(7): 1642-1653, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32305899

RESUMEN

Camera sensors rely on global or rolling shutter functions to expose an image. This fixed function approach severely limits the sensors' ability to capture high-dynamic-range (HDR) scenes and resolve high-speed dynamics. Spatially varying pixel exposures have been introduced as a powerful computational photography approach to optically encode irradiance on a sensor and computationally recover additional information of a scene, but existing approaches rely on heuristic coding schemes and bulky spatial light modulators to optically implement these exposure functions. Here, we introduce neural sensors as a methodology to optimize per-pixel shutter functions jointly with a differentiable image processing method, such as a neural network, in an end-to-end fashion. Moreover, we demonstrate how to leverage emerging programmable and re-configurable sensor-processors to implement the optimized exposure functions directly on the sensor. Our system takes specific limitations of the sensor into account to optimize physically feasible optical codes and we evaluate its performance for snapshot HDR and high-speed compressive imaging both in simulation and experimentally with real scenes.

4.
Front Robot AI ; 7: 126, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33501292

RESUMEN

Environments in which Global Positioning Systems (GPS), or more generally Global Navigation Satellite System (GNSS), signals are denied or degraded pose problems for the guidance, navigation, and control of autonomous systems. This can make operating in hostile GNSS-Impaired environments, such as indoors, or in urban and natural canyons, impossible or extremely difficult. Pixel Processor Array (PPA) cameras-in conjunction with other on-board sensors-can be used to address this problem, aiding in tracking, localization, and control. In this paper we demonstrate the use of a PPA device-the SCAMP vision chip-combining perception and compute capabilities on the same device for aiding in real-time navigation and control of aerial robots. A PPA consists of an array of Processing Elements (PEs), each of which features light capture, processing, and storage capabilities. This allows various image processing tasks to be efficiently performed directly on the sensor itself. Within this paper we demonstrate visual odometry and target identification running concurrently on-board a single PPA vision chip at a combined frequency in the region of 400 Hz. Results from outdoor multirotor test flights are given along with comparisons against baseline GPS results. The SCAMP PPA's High Dynamic Range (HDR) and ability to run multiple algorithms at adaptive rates makes the sensor well suited for addressing outdoor flight of small UAS in GNSS challenging or denied environments. HDR allows operation to continue during the transition from indoor to outdoor environments, and in other situations where there are significant variations in light levels. Additionally, the PPA only needs to output specific information such as the optic flow and target position, rather than having to output entire images. This significantly reduces the bandwidth required for communication between the sensor and on-board flight computer, enabling high frame rate, low power operation.

5.
PLoS One ; 15(12): e0242983, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33259507

RESUMEN

BACKGROUND: Antepartum fetal monitoring aims to assess fetal development and wellbeing throughout pregnancy. Current methods utilised in clinical practice are intermittent and only provide a 'snapshot' of fetal wellbeing, thus key signs of fetal demise could be missed. Continuous fetal monitoring (CFM) offers the potential to alleviate these issues by providing an objective and longitudinal overview of fetal status. Various CFM devices exist within literature; this review planned to provide a systematic overview of these devices, and specifically aimed to map the devices' design, performance and factors which affect this, whilst determining any gaps in development. METHODS: A systematic search was conducted using MEDLINE, EMBASE, CINAHL, EMCARE, BNI, Cochrane Library, Web of Science and Pubmed databases. Following the deletion of duplicates, the articles' titles and abstracts were screened and suitable papers underwent a full-text assessment prior to inclusion in the review by two independent assessors. RESULTS: The literature searches generated 4,885 hits from which 43 studies were included in the review. Twenty-four different devices were identified utilising four suitable CFM technologies: fetal electrocardiography, fetal phonocardiography, accelerometry and fetal vectorcardiography. The devices adopted various designs and signal processing methods. There was no common means of device performance assessment between different devices, which limited comparison. The device performance of fetal electrocardiography was reduced between 28 to 36 weeks' gestation and during high levels of maternal movement, and increased during night-time rest. Other factors, including maternal body mass index, fetal position, recording location, uterine activity, amniotic fluid index, number of fetuses and smoking status, as well as factors which affected alternative technologies had equivocal effects and require further investigation. CONCLUSIONS: A variety of CFM devices have been developed, however no specific approach or design appears to be advantageous due to high levels of inter-device and intra-device variability.


Asunto(s)
Monitoreo Fetal/instrumentación , Atención Prenatal , Acelerometría , Electrocardiografía , Femenino , Movimiento Fetal , Edad Gestacional , Frecuencia Cardíaca Fetal/fisiología , Humanos , Embarazo , Procesamiento de Señales Asistido por Computador
6.
Healthcare (Basel) ; 8(2)2020 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-32272756

RESUMEN

We examined the impact of a group-based self-empowerment intervention among diabetes patients, which uses multidisciplinary education, collaborative learning, peer support, and development of diabetes-specific social capital to improve glycemic control and weight management. Thirty-five patients who had primary care established at the Prisma Health Upstate, Internal Medicine Resident clinic and held the diagnosis of diabetes for longer than one year were recruited for our single-arm pilot intervention. Each group intervention session involved one to two internal medicine resident physician facilitators, a clinical diabetic educator, and 5-10 patients. Each session had a framework facilitated by the resident, with most of the discussion being patient-led, aiming to provide a collaborative learning environment and create a support group atmosphere to encourage self-empowerment. Patients' hemoglobin A1c level and body mass index (BMI) before the intervention and 3 to 6 months after completion were collected from the laboratory results obtained in the participants' routine clinic visits. All graduates from this three-week intervention were invited to attend monthly maintenance sessions, and we tracked the HgbA1c measures of 29 JUMP graduates one year after the intervention, even though 13 of the 29 chose not to participate in the monthly maintenance sessions. The pre-intervention HgbA1c level averaged 8.84%, whereas the post-intervention HgbA1c level averaged 7.81%. A paired t test showed that this pre-post difference of 1.03 percentage points was statistically significant (p = 0.0007). For BMI, there was an average decline of 0.78 from the pre-intervention mean value of 40.56 to the post-intervention mean value of 39.78 (p = 0.03). Among the 29 participants who agreed to participate in our follow-up measure of their HgbA1c status one year after the intervention, a paired t test showed that there was no significant difference between the post-JUMP measure and the follow-up measure (p = 0.808). There was no statistically significant difference between the HgbA1c level of those participating in the maintenance program and that of those not participating (post-intervention t test of between-group difference: p = 0.271; follow-up t test of between-group difference: p = 0.457). Our single-arm, pilot study of the three-week group intervention of self-empowerment shows promising results in glycemic control and weight loss. The short duration and small number of sessions expected could make it more feasible for implementation and dissemination as compared with popular intervention protocols that require much longer periods of attendance, if the effectiveness of this patient group-based self-empowerment approach can be further established by randomized controlled studies in the future.

7.
PLoS One ; 8(1): e52957, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23301008

RESUMEN

The co-occurrence of vertebrate trace and body fossils within a single geological formation is rare and the probability of these parallel records being contemporaneous (i.e. on or near the same bedding plane) is extremely low. We report here a late Pleistocene locality from the Victorian Volcanic Plains in south-eastern Australia in which demonstrably contemporaneous, but independently accumulated vertebrate trace and body fossils occur. Bite marks from a variety of taxa are also present on the bones. This site provides a unique opportunity to examine the biases of these divergent fossil records (skeletal, footprints and bite marks) that sampled a single fauna. The skeletal record produced the most complete fauna, with the footprint record indicating a markedly different faunal composition with less diversity and the feeding traces suggesting the presence, amongst others, of a predator not represented by either the skeletal or footprint records. We found that the large extinct marsupial predator Thylacoleo was the only taxon apparently represented by all three records, suggesting that the behavioral characteristics of large carnivores may increase the likelihood of their presence being detected within a fossil fauna. In contrast, Diprotodon (the largest-ever marsupial) was represented only by trace fossils at this site and was absent from the site's skeletal record, despite its being a common and easily detected presence in late Pleistocene skeletal fossil faunas elsewhere in Australia. Small mammals absent from the footprint record for the site were represented by skeletal fossils and bite marks on bones.


Asunto(s)
Fósiles , Paleontología/métodos , Animales , Australia , Huesos , Geología , Mamíferos , Factores de Tiempo
8.
Artículo en Inglés | MEDLINE | ID: mdl-21768017

RESUMEN

This paper describes the design of a programmable transmit beamformer application-specific integrated circuit (ASIC) with 8 channels for ultrasound imaging systems. The system uses a 20-MHz reference clock. A digital delay-locked loop (DLL) was designed with 50 variable delay elements, each of which provides a clock with different phase from a single reference. Two phase detectors compare the phase difference of the reference clock with the feedback clock, adjusting the delay of the delay elements to bring the feedback clock signal in phase with the reference clock signal. Two independent control voltages for the delay elements ensure that the mark space ratio of the pulses remain at 50%. By combining a 10- bit asynchronous counter with the delays from the DLL, each channel can be programmed to give a maximum time delay of 51 µs with 1 ns resolution. It can also give bursts of up to 64 pulses. Finally, for a single pulse, it can adjust the pulse width between 9 ns and 100 ns by controlling the current flowing through a capacitor in a one-shot circuit, for use with 40-MHz and 5-MHz transducers, respectively.


Asunto(s)
Procesamiento de Señales Asistido por Computador , Ultrasonografía/instrumentación , Diseño de Equipo , Retroalimentación
9.
Artículo en Inglés | MEDLINE | ID: mdl-19686993

RESUMEN

A scanning head has been designed and fabricated that incorporates a 20-MHz, 128-element linear transducer. The scanning head also incorporates -200 V pulsers and a custom 16-channel amplifier. The transducer was constructed with 28 microm PVDF film with an element pitch of 250 microm. The transducer showed an average -20 dB pulse length of 69 ns. The elements of the PVDF array were tested and found to have 7.5 mPa/ radical Hz equivalent noise pressure. The radiated power level for 32 pulsed elements was approximately 1 MPa. An imaging test shows that the system achieves axial and lateral resolutions of 40 microm and 0.2 mm, respectively. The entire scanning head dissipates approximately 1.6 W at a pulse repetition rate of 750 Hz.


Asunto(s)
Modelos Teóricos , Polivinilos/química , Transductores , Ultrasonografía/instrumentación , Algoritmos , Amplificadores Electrónicos , Brazo/irrigación sanguínea , Brazo/diagnóstico por imagen , Diseño de Equipo , Humanos , Piel/diagnóstico por imagen
10.
Appl Opt ; 44(31): 6578-92, 2005 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-16270546

RESUMEN

Design requirements for an 8000 frame/s dual-wavelength ratiometric chemical species tomography system, intended for hydrocarbon vapor imaging in one cylinder of a standard automobile engine, are examined. The design process is guided by spectroscopic measurements on iso-octane and by comprehensive results from laboratory phantoms and research engines, including results on temporal resolution performance. Novel image reconstruction techniques, necessary for this application, are presented. Recent progress toward implementation, including details of the optical access arrangement employed and signal-to-noise issues, is described. We present first cross-cylinder IR absorption measurements from a reduced channel-count (nontomographic) system and discuss the prospects for imaging.

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