Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Sensors (Basel) ; 22(1)2022 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-35009904

RESUMEN

Vibration energy harvesters in industrial applications usually take the form of cantilever oscillators covered by a layer of piezoelectric material and exploit the resonance phenomenon to improve the generated power. In many aeronautical applications, the installation of cantilever harvesters is not possible owing to the lack of room and/or safety and durability requirements. In these cases, strain piezoelectric harvesters can be adopted, which directly exploit the strain of a vibrating aeronautic component. In this research, a mathematical model of a vibrating slat is developed with the modal superposition approach and is coupled with the model of a piezo-electric patch directly bonded to the slat. The coupled model makes it possible to calculate the power generated by the strain harvester in the presence of the broad-band excitation typical of the aeronautic environment. The optimal position of the piezoelectric patch along the slat length is discussed in relation with the modes of vibration of the slat. Finally, the performance of the strain piezoelectric harvester is compared with the one of a cantilever harvester tuned to the frequency of the most excited slat mode.

2.
Ecotoxicology ; 29(6): 676-683, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32291617

RESUMEN

Salt tolerance and the possible functions of suberization on salt exclusion and secretion were examined in a dominant mangrove plant, Avicennia marina. The results showed that low salinities (10‰ and 20‰) almost has no negative effect on A. marina, however significant growth inhibitions were observed in the seedlings grown in higher salinities (30‰ and 40‰). With the increases of salinity, increased tissue Na+ content and enhanced salt secretion by glands were observed. Obvious suberization thickening were detected both in the exodermis and endodermis of the roots after salt pretreatment when compared to the roots without salt treatment. More importantly, the present data further confirmed that these root apoplastic barriers would directly decrease Na+ loading into xylem. Higher salt tolerance was observed in the seedlings pre-cultivated by salty tide when compared to fresh water cultivated A. marina. In summary, this study suggests a barrier property of suberization in dealing with salt exclusion in mangroves, a moderate salt pre-treatment may benefit plant withstanding high salinity.


Asunto(s)
Avicennia/fisiología , Tolerancia a la Sal/fisiología , Iones , Raíces de Plantas , Salinidad , Plantones , Sodio , Xilema
3.
J Asian Nat Prod Res ; 20(2): 139-147, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28595458

RESUMEN

A series of tanshinone IIA derivatives were synthesized through sulfonation, slat-forming, chlorination, and amidation reactions. Meanwhile, anti-myocardial injury activity was evaluated in vitro. D8 and D9 exhibited a slightly higher anti-myocardial injury (5.78, 7.46 µM) activity compared with esmolol (8.12 µM). In addition, they also displayed a concentration-dependent inhibition on the anti-myocardial injury.


Asunto(s)
Abietanos/síntesis química , Abietanos/farmacología , Abietanos/química , Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Lesiones Cardíacas , Estructura Molecular , Miocardio
4.
J Cell Sci ; 128(23): 4341-52, 2015 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-26483383

RESUMEN

SLAT (also known as DEF6) promotes T cell activation and differentiation by regulating NFAT-Ca(2+) signaling. However, its role in TCR-mediated inside-out signaling, which induces integrin activation and T cell adhesion, a central process in T cell immunity and inflammation, has not been explored. Here, we show that SLAT is crucial for TCR-induced adhesion to ICAM-1 and affinity maturation of LFA-1 in CD4(+) T cells. Mechanistic studies revealed that SLAT interacts, through its PH domain, with a key component of inside-out signaling, namely the active form of the small GTPase Rap1 (which has two isoforms, Rap1A and Rap1B). This interaction has been further shown to facilitate the interdependent recruitment of Rap1 and SLAT to the T cell immunological synapse upon TCR engagement. Furthermore, a SLAT mutant lacking its PH domain drastically inhibited LFA-1 activation and CD4(+) T cell adhesion. Finally, we established that a constitutively active form of Rap1, which is present at the plasma membrane, rescues the defective LFA-1 activation and ICAM-1 adhesion in SLAT-deficient (Def6(-/-)) T cells. These findings ascribe a new function to SLAT, and identify Rap1 as a target of SLAT function in TCR-mediated inside-out signaling.


Asunto(s)
Adhesión Celular/fisiología , Proteínas de Unión al ADN/metabolismo , Antígeno-1 Asociado a Función de Linfocito/metabolismo , Proteínas Nucleares/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal/fisiología , Proteínas de Unión al GTP rap/metabolismo , Proteínas de Unión al GTP rap1/metabolismo , Animales , Línea Celular , Proteínas de Unión al ADN/genética , Factores de Intercambio de Guanina Nucleótido , Antígeno-1 Asociado a Función de Linfocito/genética , Ratones , Ratones Transgénicos , Proteínas Nucleares/genética , Estructura Terciaria de Proteína , Receptores de Antígenos de Linfocitos T/genética , Proteínas de Unión al GTP rap/genética , Proteínas de Unión al GTP rap1/genética
5.
Front Robot AI ; 11: 1423319, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38993481

RESUMEN

Introduction: Robotics uptake in the aerospace industry is low, mainly due to the low-volume/high-accuracy production that aerospace manufacturers require. Furthermore, aerospace manufacturing and assembly sites are often unstructured environments not specifically suitable for robots to operate in. Methods: This paper introduces a robotic visual inspection system using off-the-shelf components able to inspect the mounting holes for wing slat actuators without the need for fixed-coordinate programming; the part just needs to be left within reach of the robot. Our system sets one of the opposed pairs of mounting holes as a reference (the "datum") and then compares the tilt of all other pairs of mounting holes with respect to it. Under the assumption that any deviation in the mounting hole tilt is not systematic but due to normal manufacturing tolerances, our system will either guarantee the correct alignment of all mounting holes or highlight the existence of misaligned holes. Results and Discussion: Computer-vision tilt measurements are performed with an error of below 0.03° using custom optimization for the sub-pixel determination of the center and radius of the mounting holes. The error introduced by the robot's motion from the datum to each of the remaining hole pairs is compensated by moving back to the datum and fixing the orientation again before moving to inspect the next hole pair. This error is estimated to be approximately 0.05°, taking the total tilt error estimation for any mounting hole pair to be 0.08° with respect to the datum. This is confirmed by manually measuring the tilt of the hole pairs using a clock gauge on a calibrated table (not used during normal operation).

6.
IEEE Trans Nucl Sci ; 59(1)2012 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-24347677

RESUMEN

In order to develop a breast-imaging system for Single Photon Emission Computed Tomography (SPECT) using slit-slat and multislit-slat collimators, we searched for optimized geometric parameters of the collimators. For this study, we employed two independent metrics to validate each result: 1) Signal to Noise Ratio (SNR) based on the Cramer-Rao lower Bound (CRB) and 2) contrast at the same noise level from an ensemble. We calculated SNR values using forward-projection data of an anthropomorphic digital phantom containing two lesions in the breast (one at the chest wall and the other at the center) with a simulated slit-slat collimator as a function of the collimator's geometric parameters. We also calculated contrast values from reconstructed images with noise. Based on the results from the slit-slat case, we investigated angular range, SNR, and contrast for the multislit-slat. We saw similar trends of the two metrics. One interesting property of the multislit-slat is that the imaging performance depends on the orientation of the field of view (FOV) of the side slits. When we compared the metric values for the slit-slat and multislit-slat, improvement was seen only when the lesion was in the FOV of the side slits. Therefore, tuning the parameters of the multislit-slat to optimally detect lesions at the chest wall might be a sensible option since the slit-slat already provides good image quality for center and superficial lesions.

7.
Ecol Evol ; 11(23): 17117-17131, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34938497

RESUMEN

There is a growing demand for ecological restoration using suitable seeds following international standards or national legal demands for local seed-sourcing. However, before selecting the appropriate geographic origin of seeds, it is vital to explore taxonomic complexity related to the focal taxa. We used ddRAD-seq to screen genomic diversity within Carex bigelowii s.lat. focussing on Norway. This species complex is considered a candidate for seeding, but presents considerable morphological, ecological, and genetic variation. The genetic structure of 132 individuals of C. bigelowii s.lat., including Carex nigra as an outgroup, was explored using ordinations, clustering analyses, and a genetic barrier algorithm. Two highly divergent clusters were evident, supporting the recognition of two taxonomic units "C. dacica" and C. bigelowii "subsp. bigelowii". Previously defined seed-sourcing regions for C. bigelowii s.lat. did not consider the known taxonomic complexity, and therefore interpreted the overall genetic structure as seed-sourcing regions, not taxa. We estimated genetic neighborhood sizes within each taxon to be 100-150 km and 300 km, respectively, indicating species-specific delimitations of local seed-sourcing regions. Frequent hybrids, local genetic distinctiveness, and suggested ecotypes add complexity to the discussed seed-sourcing regions. Our results show how genomic screening of diversity and structure in a species complex can alleviate the taxonomic impediment, inform practical questions, and legal requirements related to seed-sourcing, and together with traditional taxonomic work provide necessary information for a sound management of biodiversity.

8.
Diagnostics (Basel) ; 11(6)2021 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-34067462

RESUMEN

Mandibular fracture is one of the most frequent injuries in oral and maxillo-facial surgery. Radiologists diagnose mandibular fractures using panoramic radiography and cone-beam computed tomography (CBCT). Panoramic radiography is a conventional imaging modality, which is less complicated than CBCT. This paper proposes the diagnosis method of mandibular fractures in a panoramic radiograph based on a deep learning system without the intervention of radiologists. The deep learning system used has a one-stage detection called you only look once (YOLO). To improve detection accuracy, panoramic radiographs as input images are augmented using gamma modulation, multi-bounding boxes, single-scale luminance adaptation transform, and multi-scale luminance adaptation transform methods. Our results showed better detection performance than the conventional method using YOLO-based deep learning. Hence, it will be helpful for radiologists to double-check the diagnosis of mandibular fractures.

9.
Polymers (Basel) ; 12(9)2020 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-32842522

RESUMEN

In the present work, a novel polymer composite electrolytes (PCEs) based on poly(vinyl alcohol) (PVA): ammonium thiocyanate (NH4SCN): Cd(II)-complex plasticized with glycerol (Gly) are prepared by solution cast technique. The film structure was examined by XRD and FTIR routes. The utmost ambient temperature DC ionic conductivity (σDC) of 2.01 × 10-3 S cm-1 is achieved. The film morphology was studied by field emission scanning electron microscopy (FESEM). The trend of σDC is further confirmed with investigation of dielectric properties. Transference numbers of ions (tion) and electrons (tel) are specified to be 0.96 and 0.04, respectively. Linear sweep voltammetry (LSV) displayed that the PCE potential window is 2.1 V. The desired mixture of activated carbon (AC) and carbon black was used to fabricate the electrodes of the EDLC. Cyclic voltammetry (CV) was carried out by sandwiching the PCEs between two carbon-based electrodes, and it revealed an almost rectangular shape. The EDLC exhibited specific capacitance, energy density, and equivalent series resistance with average of 160.07F/g, 18.01Wh/kg, and 51.05Ω, respectively, within 450 cycles. The EDLC demonstrated the initial power density as 4.065 × 103 W/Kg.

10.
Phys Med ; 54: 1-14, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30336998

RESUMEN

Prompt-gamma (PG) imaging has the potential for monitoring proton therapy in real time. Different approaches are investigated. We focus on developing multi-slat collimators to image PG quanta, aiming at optimizing collimator performance to detect deviations in treatment delivery. We investigated six different multi-slat configurations, which have either optimal (analytical) intrinsic spatial resolution at fixed efficiency, or otherwise; at different distances from the proton pencil-beam axis (15 cm-35 cm). We used Geant4 to simulate irradiations of the head (energy: 130 MeV) and pelvis (200 MeV) of an anthropomorphic phantom, with and without physiologic/morphologic or setup changes of clinical dosimetric relevance. The particles escaping the phantom were transported through each of these multi-slat configurations and the gamma counts profiles were recorded at the collimator exit. Median filtering was applied to the registered PG-profiles to mitigate the effects of septa shadowing and statistical fluctuations. Time-of-flight discrimination was used to enhance the signal-to-background ratio, which appeared crucial for 200 MeV irradiations. Visual detection of the artificially introduced changes was possible by comparing the PG to the depth-dose profiles. Moreover, 2 mm range shifts could be detected in the head irradiation case using a simple linear regression fit to the falloff of the PG-profile. The influence of changes in complex, patient-like dose distributions on the PG-profiles obtained with multi-slat collimation is first studied in this work, which further gives insight on collimator design optimization and highlights its potential and simplicity for detecting proton treatment deviations over a wide range of Bragg peak positions.


Asunto(s)
Fantasmas de Imagen , Terapia de Protones/instrumentación , Cintigrafía/instrumentación , Humanos , Método de Montecarlo , Hipófisis/diagnóstico por imagen , Hipófisis/efectos de la radiación , Dosificación Radioterapéutica , Bazo/diagnóstico por imagen , Bazo/efectos de la radiación
11.
Acta Vet Scand ; 59(1): 34, 2017 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-28558798

RESUMEN

BACKGROUND: The objective was to investigate the effect of placing mats on concrete slatted floors on performance, behaviour, hoof condition, dirt scores, physiological and immunological variables of beef steers, and to compare responses with animals on out-wintering pads. Continental crossbred beef steers [n = 360; mean (±SD) initial live weight 539 kg (42.2)] were blocked by breed and live weight and randomly assigned to one of five treatments; (1) Concrete slats alone, (2) Mat 1 (Natural Rubber structure) (Durapak Rubber Products), (3) Mat 2 (Natural rubber structure) (EasyFix), (4) Mat 3 (modified ethylene vinyl acetate (EVA) foam structure) and (5) Out-wintering pads (OWP's). RESULTS: Animals on the OWPs had a greater (P < 0.05) live weight gain (P < 0.05) compared with the slat and Mat 2 treatments: results for Mat 1 and Mat 3 were the same (P > 0.05) as the other treatments. Animals on the OWPs had reduced lying percentage time compared with all the other treatments. Dry matter (DM) intake was greater for animals on the OWPs compared with all the other treatments. Carcass weight, kill out proportion, carcass fat score, carcass composition score, FCR and physiological responses were similar (P > 0.05) among treatments. No incidence of laminitis was observed among treatments. The number of hoof lesions was greater on all mat types (P < 0.05) compared with concrete slats and OWP treatments. Dirt scores were greater (P < 0.05) for animals on OWPs when measured on days 42, 84, 105, 126 and 150 compared with animals on slats. CONCLUSIONS: Under the conditions adopted for the present study, there was no evidence to suggest that animals housed on bare concrete slats were disadvantaged in respect of animal welfare compared with animals housed on other floor types. It is concluded that the welfare of steers was not adversely affected by slats compared with different mat types or OWPs.


Asunto(s)
Crianza de Animales Domésticos , Enfermedades de los Bovinos/prevención & control , Vivienda para Animales , Animales , Bovinos , Pisos y Cubiertas de Piso , Pezuñas y Garras , Masculino , Carne Roja , Estaciones del Año , Resultado del Tratamiento
12.
Ann Stomatol (Roma) ; 8(3): 123-130, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29682225

RESUMEN

BACKGROUND: The purpose of this study was to report the outcome of the management of both horizontal and vertical defects of alveolar crest using the bone slat technique approach in conjunction with third molar removal prior to implant placement in the aesthetic area. METHODS: We present a 20-year-old female patient who lost a maxillary lateral incisor. The objective of treatment was to replace the lateral incisor with an implant-supported crown restoration without interfering with the integrity and topography of the adjacent gingival tissues. Because the future implant site showed horizontal and vertical bone defect the Authors decided to perform bone regeneration. The need for such bone augmentation in the younger patient often coincides with the timing for third molar removal. By combining third molar extraction with bone harvest and alveolar grafting, the patient undergoes only one surgical approach. The bone height (9.5 mm) and width (5.7 mm) were measured at the point of interest (tooth 12) both before and after implant placement in the reconstructed panoramic and parasagittal views by Cone Beam Computed Tomography (CBCT) scan. RESULTS: The final results demonstrated an increase in length of 5 mm after bone slat technique (from 9.5 mm to 13.5 mm) and an increase in width of 1 mm (from 5.7 mm to 6.7 mm). ISQ measurements were recorded at the time of implant placement (the mean was: 68.5) and immediately after individualized screw-retained provisional crown (the mean was: 77). CONCLUSIONS: This technique is reliable and aesthetic and functional results appear to be stable and respect this requisite: simple and fast graft harvesting and low risk of morbidity especially in conjunction with third molar removal.

13.
Ann Stomatol (Roma) ; 8(1): 39-44, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28736606

RESUMEN

BACKGROUND: The reconstruction of alveolar ridges for implant placement is still a challenging surgical procedure, especially in the case of extensive vertical and horizontal bone atrophy. OBJECTIVE: The objective of the present study was to evaluate the quantity and quality of newly regenerated bone; clinically by means of direct clinical measuring, ridges augmented by autogenous cortical bone associated with autogenous particulate bone graft in the posterior lower jaw defect. METHODS: For the preliminary study, a bone defects in partially edentulous in patient aged 52 years were selected to receive horizontal ridge augumentation prior autolougous bone block and particulate graft. The donor site was the ramus of the same side. Prior the clinical evaluation, periapical X-ray and the cone beam computerized tomography (CBCT) was observed the quality, quantity and the stability the soft and hard tissue healing process, final result and the outcome. RESULT: The bone augmentation achieved with this technique created the ideal bone volume of hard and soft tissue, in quantity and quality, for placement of implants. CONCLUSION: The surgical technique was found to be easy in terms of technique and surgical trauma.

14.
Front Immunol ; 8: 1163, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28993769

RESUMEN

Regulatory T cells (Tregs) control key events of immune tolerance, primarily by suppression of effector T cells. We previously revealed that Tregs rapidly suppress T cell receptor (TCR)-induced calcium store depletion in conventional CD4+CD25- T cells (Tcons) independently of IP3 levels, consequently inhibiting NFAT signaling and effector cytokine expression. Here, we study Treg suppression mechanisms through unbiased phosphoproteomics of primary human Tcons upon TCR stimulation and Treg-mediated suppression, respectively. Tregs induced a state of overall decreased phosphorylation as opposed to TCR stimulation. We discovered novel phosphosites (T595_S597) in the DEF6 (SLAT) protein that were phosphorylated upon TCR stimulation and conversely dephosphorylated upon coculture with Tregs. Mutation of these DEF6 phosphosites abrogated interaction of DEF6 with the IP3 receptor and affected NFAT activation and cytokine transcription in primary Tcons. This novel mechanism and phosphoproteomics data resource may aid in modifying sensitivity of Tcons to Treg-mediated suppression in autoimmune disease or cancer.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA