183 research outputs found
Plant Programmed Cell Death Caused by an Autoactive Form of Prf Is Suppressed by Co-Expression of the Prf LRR Domain
No full textIn tomato, the NBARC-LRR resistance (R) protein Prf acts in concert with the Pto or Fen kinase to determine immunity against Pseudomonas syringae pv. tomato (Pst). Prf-mediated defense signaling is initiated by the recognition of two sequence-unrelated Pst-secreted effector proteins, AvrPto and AvrPtoB, by tomato Pto or Fen. Prf detects these interactions and activates signaling leading to host defense responses including localized programmed cell death (PCD) that is associated with the arrest of Pst growth. We found that Prf variants with single amino acid substitutions at D1416 in the IHD motif (isoleucine-histidine-aspartic acid) in the NBARC domain cause effector-independent PCD when transiently expressed in leaves of Nicotiana benthamiana, suggesting D1416 plays an important role in activation of Prf. The N-terminal region of Prf (NPrf) and the LRR domain are required for this autoactive Prf cell death signaling but dispensable for accumulation of the Prf(D1416V) protein. Significantly, co-expression of the Prf LRR but not NPrf, with Prf(D1416V), AvrPto/Pto, AvrPtoB/Pto, an autoactive form of Pto (Pto(Y207D)), or Fen completely suppresses PCD. However, the Prf LRR does not interfere with PCD caused by Rpi-blb1(D475V), a distinct R protein-mediated PCD signaling event, or that caused by overexpression of MAPKKK alpha, a protein acting downstream of Prf. Furthermore, we found the Prf(D1416V) protein is unable to accumulate in plant cells when co-expressed with the Prf LRR domain, likely explaining the cell death suppression. The mechanism for the LRR-induced degradation of Prf(D1416V) is unknown but may involve interference in the intramolecular interactions of Prf or to binding of the unattached LRR to other host proteins that are needed for Prf stability
PRF Sampling Strategies for SwarmSAR Systems
No full textThe work investigates staggered and random PRF (Pulse Repetition Frequency) strategies for a close formation of small Synthetic Aperture Radar (SAR) satellites operating in a multistatic configuration. The satellites are positioned within a fraction of the along-track critical baseline, hence allowing for the application of Displaced Phase Center image formation approaches. The performance of regular and random pulse sampling schemes is in particular assessed for a single-input multiple-output (SIMO) S-Band constellation, whose feasibility is further analyzed in relation to the number of satellites and their antenna size.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Optical and Laser Remote SensingMicrowave Sensing, Signals & SystemsMathematical Geodesy and PositioningAtmospheric Remote Sensin
Measuring RF-Induced Heating of a Phantom with PRF Shift Thermometry
No full textUnder MR-avbildning simuleres den spesifikke absorpsjonsraten (SAR) for å sikre at oppvarmingen som følge av bildesekvensens radiofrekvenspulser (RF) ikke overskrider de regulatoriske grensene. Å verifisere simuleringene ved å måle selve oppvarmingen i fantomer med enkel geometri er derfor viktig. Én metode for å måle temperaturendringer er PRF-skifttermometri, som består av å ta fasebilder og konvertere dem til temperaturkart. Denne masteroppgaven undersøker om PRF-skifttermometri ved 7T, kombinert med en temperatursensor for 0. og 1. ordens magnetfeltdriftskorreksjon, er nøyaktig nok til å måle den RF-induserte oppvarmingen av et fantom som følge av bildesekvensen brukt til termometrien. En GRE-sekvens med justerbar varmepuls ble laget slik at sekvensens SAR kunne justeres uten å endre opptaksparameterne. Serier med 77 fasebilder ble tatt sekvensielt i løpet av 10 minutter for å måle temperaturendringen indusert av bildesekvensen selv. Et tilpasset sfærisk agarfantom ble brukt til eksperimentene. Serien av fasebilder ble konvertert til temperaturkart, og 0. og 1. ordens romlig drift ble korrigert ved hjelp av en temperatursensor. De resulterende temperaturkartene ble evaluert. Nøyaktigheten til temperaturkartene oppnådd med PRF-skifttermometri, som presentert i denne rapporten, tilfredsstilte ikke det forhåndsdefinerte nøyaktighetsmålet på 0,1°C i hele bildet. Ved temperatursensoren som ble brukt til validering varierte den beregnede RMSE verdien fra 0,12°C til 0,37°C for de 10 minutter lange seriene. Feilene så ut til å skyldes romlig drift av 2. orden, som virket reproduserbar og derfor kanskje mulig å fjerne. Ytterligere eksperimenter og arbeid med sekvensen og post-prosessering kan mulig forbedre nøyaktigheten slik at metoden kan brukes til verifikasjon av SAR-beregninger i fremtiden.During an MRI scan, the Specific Absorption Rate (SAR) is simulated to ensure the heating due to the imaging sequence’s Radio Frequency (RF) pulses does not exceed the regulatory limits. Verifying the simulations by measuring the actual heating in phantoms with simple geometry is therefore important. One method of measuring temperature change is PRF shift thermometry, which consists of acquiring phase images and converting them to temperature maps. This master’s thesis investigates whether PRF shift thermometry at 7T, combined with a temperature probe for 0th and 1st order magnetic field drift correction, is accurate enough to measure the RF-induced heating of a phantom due to the thermometry imaging sequence itself. A custom GRE sequence with an adjustable heating pulse was made so the sequence SAR could be adjusted without changing the imaging parameters. Series of 77 phase images were acquired sequentially for 10 minutes with the custom sequence to measure the temperature change induced by the imaging sequence. A custom spherical agar phantom was used for the experiments. The series of phase images were converted to temperature maps, and the 0th and 1st order spatial drift was corrected using a temperature probe. The resulting temperature maps were evaluated. The accuracy of the temperature maps acquired with the PRF shift thermometry method proposed in this report did not satisfy the predefined accuracy goal of 0.1°C at all spatial locations. At a temperature probe used for validation, the calculated Root Mean Square Error (RMSE) ranged from 0.12°C to 0.37°C for the 10 minutes series. The errors seemed to result from 2nd order spatial drift, which looked reproducible and may therefore be possible to remove. Further experiments and work with the sequence and post-processing may improve the accuracy so that the method can be used for verification of SAR calculations in the future
Measuring RF-Induced Heating of a Phantom with PRF Shift Thermometry
No full textUnder MR-avbildning simuleres den spesifikke absorpsjonsraten (SAR) for å sikre at oppvarmingen som følge av bildesekvensens radiofrekvenspulser (RF) ikke overskrider de regulatoriske grensene. Å verifisere simuleringene ved å måle selve oppvarmingen i fantomer med enkel geometri er derfor viktig. Én metode for å måle temperaturendringer er PRF-skifttermometri, som består av å ta fasebilder og konvertere dem til temperaturkart. Denne masteroppgaven undersøker om PRF-skifttermometri ved 7T, kombinert med en temperatursensor for 0. og 1. ordens magnetfeltdriftskorreksjon, er nøyaktig nok til å måle den RF-induserte oppvarmingen av et fantom som følge av bildesekvensen brukt til termometrien. En GRE-sekvens med justerbar varmepuls ble laget slik at sekvensens SAR kunne justeres uten å endre opptaksparameterne. Serier med 77 fasebilder ble tatt sekvensielt i løpet av 10 minutter for å måle temperaturendringen indusert av bildesekvensen selv. Et tilpasset sfærisk agarfantom ble brukt til eksperimentene. Serien av fasebilder ble konvertert til temperaturkart, og 0. og 1. ordens romlig drift ble korrigert ved hjelp av en temperatursensor. De resulterende temperaturkartene ble evaluert. Nøyaktigheten til temperaturkartene oppnådd med PRF-skifttermometri, som presentert i denne rapporten, tilfredsstilte ikke det forhåndsdefinerte nøyaktighetsmålet på 0,1°C i hele bildet. Ved temperatursensoren som ble brukt til validering varierte den beregnede RMSE verdien fra 0,12°C til 0,37°C for de 10 minutter lange seriene. Feilene så ut til å skyldes romlig drift av 2. orden, som virket reproduserbar og derfor kanskje mulig å fjerne. Ytterligere eksperimenter og arbeid med sekvensen og post-prosessering kan mulig forbedre nøyaktigheten slik at metoden kan brukes til verifikasjon av SAR-beregninger i fremtiden
Effects of autologous platelet-rich fibrin in post-extraction alveolar sockets: A randomized, controlled split-mouth trial in dogs with spontaneous periodontal disease
No full textPeriodontal disease (PD) is a common inflammatory condition in dogs; in severe stages, dental extraction is frequently required. Platelet-rich fibrin (PRF) has been used in human oral surgical procedures and has been experimentally tested on post-extraction sockets in healthy dogs. This is the first split-mouth, randomized, controlled trial designed to compare post-extractive alveolar socket healing with and without topical application of PRF in canine spontaneous PD. Clinical evaluation, radiographic density, and histological scores for inflammation and regeneration were assessed at recruitment (T0) and after a three-week follow up (T1) on 12 dogs, for a total of 31 pairs of sockets. No complications or clinically evident differences between the treated sites and the control sites were observed. Comparing the radiographic densities of the extraction sites measured at T0 and T1, a significant enhancement was observed within the PRF group, but not within control group. The histological score decreased significantly from T0 to T1 within group PRF, but not within the control group; at T1, the PRF group showed a significantly lower histological score than the control group. These findings suggest that PRF could be able to stimulate the natural process of tissue healing and regeneration of post-extraction sites in dogs with spontaneous periodontal disease (PD)
Effet de la rigidité, du taux du polymère renforcé de fibres (PRF) et de l’armature transversale interne sur la contribution à la résistance à l’effort tranchant d’un renfort en PRF collé en surface : état de l’art et besoins en recherche
No full textLe prsent article traite du renforcement en cisaillement des poutres en BA l’aide de PRF coll en surface. La premire partie de l’tude dcrit l’volution des normes nord-amricaines ce sujet. La seconde partie prsente une analyse exhaustive des paramtres majeurs influenant la contribution du PRF la rsistance, incluant une comparaison des prdictions des normes avec les rsultats des essais exprimentaux rapports dans la littrature. Il ressort que plusieurs paramtres majeurs n’ont fait l’objet, ce jour, que de peu d’investigations : (i) le taux de l’acier transversal interne et (ii) le nombre de couches des PRF colls en surface. Une base de donnes extraite partir des tudes exprimentales a t ensuite labore. Les rsultats obtenus confirment l’existence d’une interaction entre le PRF et l’acier transversal quant la reprise des efforts tranchants. Ils mettent galement en vidence l’existence d’une rigidit optimale du PRF au-del de laquelle le gain en rsistance attribu au PRF coll en surface est plafonn.
This paper deals with the shear strengthening of reinforced concrete (RC) beams using externally bonded fiber-reinforced polymer (EB FRP) composite materials. The first part of the paper reviews the evolution of North American codes and standards for the shear resistance of RC beams strengthened with EB FRP composites, whereas the second part provides a comprehensive analysis of the major parameters influencing the contribution of FRP to shear resistance. It also presents a comparison of the predictions of current design standards (ACI 440.2R 2017; CSA/S6 2019; CSA/S806 2012; fib-TG9.3 2001) with the results of experimental tests reported in the literature. The study shows that major parameters influencing the shear behaviour have received little attention. These parameters include in particular: (i) the presence and ratio of internal transverse steel reinforcement and (ii) the number of EB FRP plies (layers). This may explain the observed discrepancies between the prediction models of existing equations for shear resistance and the results obtained from tests. Consequently, a database extracted from the experimental studies was developed as part of this study. The results obtained highlight and confirm the existence of an interaction between the EB FRP composites and the internal transverse steel reinforcement with regard to shear resistance of RC beams. They also show the existence of an optimal FRP stiffness beyond which there is no substantial gain in resistance attributed to the EB FRP.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Three-dimensional evaluation of the effects of injectable platelet rich fibrin (i-PRF) on alveolar bone and root length during orthodontic treatment: a randomized split mouth trial
No full textBackground: The role of injectable platelet rich fibrin (i-PRF) in orthodontic treatment has not been investigated with focus on its effect on dental and bony periodontal elements. Objective: To evaluate the efficacy of i-PRF in bone preservation and prevention of root resorption. Methods: A randomized split-mouth controlled trial included 21 patients aged 16–28 years (20.85 ± 3.85), who were treated for Class II malocclusion with the extraction of the maxillary first premolars. Right and left sides were randomly allocated to either experimental treated with i-PRF or control sides. After the leveling and alignment phase, the canines were retracted with 150gm forces. The i-PRF was prepared from the blood of each patient following a precise protocol, then injected immediately before canine retraction on the buccal and palatal aspects of the extraction sites. Localized maxillary cone beam computed tomography scans were taken before and after canine retraction to measure alveolar bone height and thickness and canine root length (indicative of root resorption), and the presence of dehiscence and fenestration. Paired sample t-tests and Wilcoxon signed rank tests were used to compare the changes between groups. Results: No statistically significant differences in bone height, bone thickness were found between sides and between pre- and post-retraction period. However, root length was reduced post retraction but did not differ between sides. In both groups, postoperative dehiscence was observed buccally and palatally and fenestrations were recorded on only the buccal aspect. Conclusions: I-PRF did not affect bone quality during canine retraction or prevent canine root resorption. I-PRF did not reduce the prevalence of dehiscence and fenestration. Trial registration ClinicalTrials.gov (identifier number: NCT 03399760. 16/01/2018). © 2021, The Author(s)
Development of a reduced primary reference fuel-oxymethylene dimethyl ether (PRF-OMEx) mechanism for diesel engine applications
No full text[EN] Oxymethylene dimethyl ethers (OMEx), having a chemical formula of CH3O-(CH2O)(x)-CH3 where x varies from 1 to 5, have been widely considered as a promising fuel to partially replace diesel in CI engines in terms of reducing soot emissions. This work is focused on developing a reduced primary reference fuel (PRF)-OMEx chemical mechanism to better describe the combustion and emission characteristics of gasoline/diesel blends with OMEx. The novelty of this work lies in the fact that the OMEx part of the mechanism is represented not only by OME3 as done in most studies found in literature, but also with other OME chain lengths that is, OME2-4 which are considered to be optimum and better represent the commercial OMEx blends. For this purpose, a detailed OMEx mechanism is reduced by applying different reduction techniques considering a wide range of operating conditions including pressure, temperatures, equivalence ratios and fuel compositions. The result is merged with an already validated PRF mechanism to form a reduced PRF-OMEx mechanism consisting of 213 species and 840 reactions. The newly formed mechanism is validated against a wide set of experimental data including ignition delay times, laminar flame speeds and species concentration profiles. Furthermore, a rigorous set of numerical simulations for various diesel-OMEx blends in a compression ignition engine are carried out at two different operating points to validate the developed mechanism. Simulation results highlight that the developed mechanism not only replicates the experimental behavior in terms of in-cylinder pressure and heat release rate but exhibits a better combustion phasing closer to experimental data when compared with other mechanisms where only OME3 is utilized to represent OMEx. Overall, the developed PRF-OMEx mechanism proves to be realistic and suitable for application in engine combustion simulations involving gasoline/diesel and OMEx blends.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work has been partially funded by Universitat Politecnica de Valencia through grant agreement UPV-Subprograma 2 (PAID-01-22).García-Oliver, JM.;Novella Rosa, R.;Micó, C.;Khalid, UB. (2024). Development of a reduced primary reference fuel-oxymethylene dimethyl ether (PRF-OMEx) mechanism for diesel engine applications. International Journal of Engine Research. 25(10):1898-1913. https://doi.org/10.1177/14680874241255755S18981913251
Regeneração óssea guiada associada a osso xenógeno e plasma rico em fibrina : relato de caso
No full textOrientador : Prof. Marco Aurélio JaszczerskiMonografia (especialização) - Universidade Federal do Paraná, Setor de Ciências da Saúde, Curso de Especialização em ImplantodontiaInclui referênciasResumo : A reabilitação oral com implantes dentários é um procedimento que requer volume ósseo suficiente da crista óssea alveolar para viabilizar sua instalação e promover uma reabilitação funcional e estética. Quando se verifica insuficiente volume ósseo, são necessários procedimentos de aumento com enxerto para obter volume suficiente para ancoragem dos implantes. Neste contexto a regeneração óssea guiada (ROG), pode viabilizar ganhos expressivos, cujo seu objetivo é promover a formação óssea em deformidades ósseas, que aliados a Fibrina rica em plaquetas e leucócito (L-PRF) e o substituto ósseo Bio Oss®, podem promover um ganho exponencial em qualidade e quantidade óssea. Com propósito de avaliar a regeneração óssea guiada e associadas ao PRF e osso xenógeno, os quais se destacam pela sua ação terapêutica e inovadora de mediadores biológicos, capazes de promover eventos cicatriciais como: quimiotaxia, mitogênese, angiogênese, o presente artigo têm como objetivo: analisar a eficácia do PRF associado ao Bio- Oss®, frente ao processo de reparo tecidual, seguindo os princípios da Regeneração óssea guiada, observando resultados obtidos com neoformação óssea, através de exames de tomografia computadorizada do tipo cone bean. Palavras-chave: Reparação tecidual. Osteogênese. PRF. LPRF. Regeneração óssea guiada e Aumento ósseo vertical
Development of the CMS detector for the CERN LHC Run 3
No full textA preprint version of this article is available at arXiv:2309.05466v1 [physics.ins-det], https://arxiv.org/abs/2309.05466v1 . Comments: Submitted to the Journal of Instrumentation. All figures and tables can be found at https://cms-results.web.cern.ch/cms-results/public-results/publications/PRF-21-001 (CMS Public Pages). Report number: CMS-PRF-21-001, CERN-EP-2023-136.Since the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger.SCOAP3
- …
