16,688 research outputs found
Recent Results From the EU POF-PLUS Project: Multi-Gigabit Transmission Over 1 mm Core Diameter Plastic Optical Fibers
No full textRecent activity to achieve multi-gigabit transmission over 1 mm core diameter graded-index and step-index plastic optical fibers for distances up to 50 meters is reported in this paper. By employing a simple intensity-modulated direct-detection system with pulse amplitude or digital multi-tone modulation techniques, low-cost transceivers and easy to install large-core POFs, it is demonstrated that multi-gigabit transmission up to 10 Gbit/s over 1-mm core diameter POF infrastructure is feasible. The results presented in this paper were obtained in the EU FP7 POF-PLUS project, which focused on applications in different scenarios, such as in next-generation in-building residential networks and in datacom applications
Agenesis: pilot case report by 2.9 mm implant
No full textThe agenesis of the upper lateral incisor is one of the most frequent aesthetic-functional problems in dentistry. The reported case concerns a 49 years old male patient with bilateral agenesis of teeth 1.2-2.2 and a root stump of tooth 5.2 temporarily rehabilitated through a Maryland bridge. Without orthodontic treatment, the only solution for implant-prosthetic rehabilitation of tooth 1.2 results therefore in the use of a 2.9 mm diameter implant. The clinical and radiographic control of the implant and the gingival stability at a distance of 1 year gives a positive result both clinically and radiographically. The use of the implant with a 2.9 mm diameter is therefore indicated in extreme cases of limited bone availability
Nifedipine stimulates endothelial progenitor cell migratory ability by reducing intracellular oxidative stress
No full textNifedipine improves the migratory ability of circulating endothelial progenitor cells depending on manganese superoxide dismutase upregulation
No full textBACKGROUND:
Migratory ability of resident endothelial cells and their circulating progenitors, that is endothelial progenitor cells (EPCs), represent a crucial event in vascular repairing processes. Although oxidants are known to counteract the migratory ability of resident endothelial cells, their possible role in modulating EPC motility is unknown. EPCs exhibit stronger resistance to oxidants than mature endothelial cells mainly because of higher expression of manganese (Mn) superoxide dismutase (SOD). As nifedipine is a dihydropyridine calcium antagonist known to enhance MnSOD expression in mature endothelial cells, we investigated the effects of nifedipine on MnSOD expression and motility in EPCs.
METHODS AND RESULTS:
EPCs were isolated from peripheral blood of healthy donors and cultured in fibronectin-coated flasks. Nifedipine improved both motility of cultured EPCs (+55% vs. control, P = 0.007) and their adhesion to tumor necrosis factor-alpha-activated mature endothelial cells (+33% vs. control, P = 0.03). Reduction of EPC dichlorofluorescein content (-32% vs. control, P = 0.009) and a parallel increase in nitrite plus nitrate concentration in EPC supernatants (+25% vs. control, P = 0.009) were also observed. The study of SOD showed a nifedipine-dependent upregulation of MnSOD in a time-dependent and dose-dependent manner. MnSOD expression blockade by RNA interference abolished nifedipine effect on EPC motility. Although nifedipine also increased vascular endothelial growth factor (VEGF) release from EPCs, its effect on EPC motility was unaffected by an anti-VEGF antibody.
CONCLUSION:
Nifedipine improves EPC motility due to MnSOD upregulation. The capability of this dihydropyridine calcium antagonist to reduce cardiovascular events might also be related to improved EPC function
Employing M1 direct calibration/de-embedding approaches for large signal model validation at mm-wave frequencies
No full textIn this contribution, we employ direct calibration/de-embedding approaches to validate the large signal device model of state-of-the-art HBTs and CMOS technologies operating in the mm-wave frequency band WR6. The capability of placing the first tier calibration reference plane in close proximity to the DUT allows the large signal metric to be directly compared with foundry models.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.Electronic
Measurement of the inter-foot distance using a Time-of-Flight proximity sensor: preliminary evaluation during leg oscillation exercises
No full textThe distance between the feet during walking could be a key factor to better understand gait stability. The aim of this work was to investigate the application of an Infrared Timeof-Flight sensor in the inter-foot distance estimation during leg oscillation exercises. The results, compared to a stereophotogrammetric system used as gold standard, showed a mean absolute error between 3.6 mm and 6.9 mm and a mean absolute percentage error in the range of 1.9% to 3.8%. An improvement of 50% (6 mm) in the inter-foot distance accuracy, compared to a wearable platform based on ultrasound and inertial sensors, was observed
Dynamic Estimation of Vital Signs with mm-wave FMCW Radar
No full textIn this paper, we propose a method for continuous monitoring of vital signs-in particular, respiration frequency-with a commercial mm-wave radar. The nearly constant frequency (NCF) model is adopted to represent chest displacement due to respiration and simulate radar response. Based on this model, an extended Kalman filter (EKF) based estimator is developed to track the breathing frequency of a person. The impact of dynamic model parameters is investigated in numerical simulation. The possibility to track breathing frequency with the proposed method is demonstrated by experimental data processing. 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.Microwave Sensing, Signals & System
Comportamento meccanico di tamponamenti in blocchi di laterizio rettificati e giunti sottili
No full textRecentemente, si è posta l’attenzione, anche in Italia, su un nuovo sistema costruttivo per la realizzazione di murature non portanti, basato sull’impiego di blocchi rettificati, tali da consentire l’esecuzione di letti “sottili” di malta, dell’ordine di 1-3 mm di spessore. Al fine di determinare il comportamento sotto carico di elementi costruttivi realizzati con la tecnologia descritta, è stata intrapresa una campagna di ricerche incentrata, oltre che sullo studio del comportamento meccanico degli elementi costituenti, blocchi e collanti, sulla valutazione della risposta di elementi strutturali di grandi dimensioni, alle azioni sia complanari che fuori piano. Lo studio è stato completato con la messa a punto di modelli agli elementi finiti capaci di descrivere il comportamento rilevato sperimentalmente e quindi utili per estendere i risultati ad elementi strutturali diversi, per forma e modalità di carico
A 23-to-29GHz Receiver with mm-Wave N-Input-N-Output Spatial Notch Filtering and Autonomous Notch-Steering Achieving 20-to-40dB mm-Wave Spatial Rejection and -14dBm In-Notch IP1 dB
No full textDigital beamforming receivers (RXs) support MIMO operation and offer great flexibility and accuracy in multi-beam formation and calibration. However, compared with analog phased-array and hybrid systems, due to the absence of any rejection for spatial in-band blockers, the RX/ADC dynamic range and linearity should be high enough to prevent array saturation. Therefore, the use of self-steering spatial notch filters (SNFs) is necessary to aid the digital beamformers and reduce RX/ADC power consumption while strong blockers exist. To address that, the sub-6GHz RXs in [1], [2] synthesize a baseband spatial notch impedance and translate it to RF by passive mixers. However, this technique cannot be directly applied at mm-wave frequencies as the impedance translational performance of the passive mixers degrades significantly. Hence, the mm-wave beamformer in [3] realizes a cascadable SNF at an intermediate frequency (IF). However, the front-end mm-wave components like mixers and phase shifters have to tolerate strong blockers, thus degrading RX linearity. Besides, it uses multiple IF buffers and VGAs for signal scaling and combining, which could be power-hungry if a similar method is adopted to realize a mm-wave SNF. To improve on those limitations, we propose a scalable SNF structure, which (1) suppresses the strongest in-band blocker at mm-wave frequencies, (2) supports N-input-N-output MIMOs, and (3) requires no active blocks except the phase shifters. A two-step autonomous notch-steering technique is also developed to adjust the SNF notch direction power-efficiently and accurately.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.Electronic
Experiencing the armed struggle : the Soweto generation and after
No full textIncludes bibliographical references (p. 354-369).This study explores the experiences of the rank-and-file soldiers of Umkhonto we Sizwe and the Azanian People's Liberation Anny. Extensive interviews by the author and other researchers reveal the voices of the soldiers themselves. The African National Congress and Pan African Congress archives at the University of the Western Cape and the University of Fort Hare supplement and verify these oral testimonies, as do some published sources. Most previously published materials about the armed struggle against apartheid have already focused on diplomacy, strategy and tactics, operations, leadership, and human rights abuses to the neglect of the soldiers' actual experiences. This study complements these with significant new oral history materials from the Soweto generation of soldiers and their successors. When dealing with MK, many authors have documented issues of the camp structure in Angola, and operations inside South Africa, so much of this detail is only addressed briefly, leaving space to explore the soldiers' experiences. In the case of APLA, very little has been written on its history, and more detail is provided on these subjects. This study therefore deals with the soldiers' politicisation and motivation for joining the armed struggle, their experiences in leaving South Africa and training in exile, the crises in exile which limited their effectiveness for a time, their return to fight in South Africa, and their difficulties in the "new" South Africa. These materials reveal that vast problems remain facing these veterans of the struggle against apartheid, and that they have the potential, if properly supported and employed, to contribute substantially to the development of present day South Africa. Conversely, if their neglect continues, they also have the potential to bring vast harm to the country. Further use of the investigative tools of oral history, especially if extended to the former soldiers' vernacular languages, is necessary to augment the history of South Africa, and these soldiers' contributions
- …
