The use of the rapid D-dimer test for the exclusion of acute venous thromboembolism in a regional hospital.

The performance of rapid D-dimer ELISA assay has been validated as a part of various diagnostic work-ups in tertiary care hospitals for the exclusion of acute thromboembolism in the medical emergency department. In order to measure the performance of this test outside of predetermined protocols and in a different medical setting, we retrospectively analysed a cohort of adult patients admitted to the emergency department of a regional hospital with a suspicion of acute venous thromboembolism. All D-dimer assays performed during an 18-month period were retrieved. The patients' data were collected from hospital charts. Six-month follow-up was determined either by a written or telephone questionnaire or after contact with the patient's physician. The patients for whom this process was completed were included in the study and a retrospective diagnostic assessment was performed using a combination of clinical probability and objective testing. The diagnosis was then compared to the result of the initial D-dimer assay. During the study period 494 patients were included with 110 venous thromboembolic episodes. The sensitivity and negative predictive value of the D-dimer assay were respectively 94.5% (95% CI 88.4 to 97.7%) and 96.8% (95% CI 93.2 to 98.7%). The yield of the rapid D-dimer assay in this study is comparable to the results of management studies performed in tertiary centres. D-dimer ELISA assay can be used to exclude venous thromboembolism, particularly in cases with a low clinical probability, in the emergency department and for larger populations in various clinical settings, even in the absence of a formal diagnostic work-up. False negative results can occur, particularly in the presence of a high clinical probability of acute thromboembolism

Modeling of dielectric material interfaces for the radial point interpolation time-domain method

Copyright © 2009 IEEEThe Radial Point Interpolation Time-Domain (RPITD) method is a flavor of meshless domain discretization methods applicable to computational electromagnetics. Meshless methods do not require an explicit mesh topology, but rather rely on a representation of a physical model as a node distribution. This is firstly advantageous for modeling of conformal boundaries and multi-scale geometries. But as the most attractive feature, the node arrangements can be adapted on-the-fly. The RPITD method is based on interpolation of the field distribution using radial and monomial basis functions. This paper introduces a technique to model arbitrarily shaped dielectric interfaces in the framework of meshless methods. Using the proposed technique, errors associated to the interpolation of non-smooth fields at material interfaces are reduced, as demonstrated for 2D-TE modes. This allows for accurate modeling of interfaces with dielectric contrast. Unlike previous publications which modify the basis functions at interfaces, a physically motivated correction term is introduced here. Errors in the vicinity of material interfaces decrease significantly and simulation accuracy is generally improved.Thomas Kaufmann, Thomas Merz, Christophe Fumeaux and Rudiger Vahldiec

Wearable Quarter-Wave Folded Microstrip Antenna for Passive UHF RFID Applications

A wearable low-profile inset-fed quarter-wave folded microstrip patch antenna for noninvasive activity monitoring of elderly is presented. The proposed antenna is embedded with a sensor-enabled passive radio-frequency identification (RFID) tag operating in the ultra-high frequency (UHF) industrial-scientific-medical (ISM) band around 900 MHz. The device exhibits a low and narrow profile based on a planar folded quarter-wave length patch structure and is integrated on a flexible substrate to maximise comfort to the wearer. An extended ground plane made from silver fabric successfully minimises the impact of the human body on the antenna performance. Measurements on a prototype demonstrate a reflection coefficient (S₁₁) of −30 dB at resonance and a −10 dB bandwidth from 920 MHz to 926 MHz. Simulation results predict a maximum gain of 2.8 dBi. This is confirmed by tag measurements where a 4-meter read range is achieved using a transmit power of 30 dBm, for the case where the passive wearable tag antenna is mounted on a body in a practical setting. This represents an almost 40% increase in read range over an existing dipole antenna placed over a 10 mm isolator layer on a human subject.Thomas Kaufmann, Damith C. Ranasinghe, Ming Zhou, and Christophe Fumeau

Est-il possible d'optimiser le traitement médicamenteux des patients âgés ?

Contexte: La polymédication, définie ici comme la prescription simultanée de M 4 médicaments, est fréquente chez les personnes de M 65 ans. Celle-ci peut s'accompagner d'une mauvaise adhérence aux traitements et provoquer des effets indésirables. Cette revue systématique a évalué l'efficacité des interventions visant à améliorer l'adéquation de la polymédication chez la personne âgée (M 65 ans) présentant deux maladies chroniques ou plus

A modular textile antenna design using snap-on buttons for wearable applications

An antenna design concept with detachable radiation elements offering modular geometry reconfigurabilities for wearable applications is presented. By utilizing snap-on buttons, both as the radio-frequency (RF) connection and mechanical holding mechanism, different modularly interchangeable microstrip patches are employed to demonstrate geometry reconfigurabilities in terms of polarization and resonance frequency. The uniqueness of the design arises from the fact that all configurations share one common feed structure which consists of a two-layered substrate including snap-on buttons, a ground plane, and a proximity coupled feed. To show the concept, modular realizations with different functionalities in terms of polarization or resonance frequency are demonstrated in this paper. First, a detachable patch offering interchangeable right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) at 5 GHz is proposed. Second, a demonstration of a planar inverted-F antenna (PIFA) concept offering interchangeable resonance frequencies for the 2.4- and 5.3-GHz bands of wireless local area networks (WLAN) is given. Finally, a patch module designed for 8-GHz operation is presented to show the versatility in frequency modularity. Experimental results of the fabricated antennas in freeAn antenna design concept with detachable radiation elements offering modular geometry reconfigurabilities for wearable applications is presented. By utilizing snap-on buttons, both as the radio-frequency (RF) connection and mechanical holding mechanism, different modularly interchangeable microstrip patches are employed to demonstrate geometry reconfigurabilities in terms of polarization and resonance frequency. The uniqueness of the design arises from the fact that all configurations share one common feed structure which consists of a two-layered substrate including snap-on buttons, a ground plane, and a proximity coupled feed. To show the concept, modular realizations with - ifferent functionalities in terms of polarization or resonance frequency are demonstrated in this paper. First, a detachable patch offering interchangeable right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) at 5 GHz is proposed. Second, a demonstration of a planar inverted-F antenna (PIFA) concept offering interchangeable resonance frequencies for the 2.4- and 5.3-GHz bands of wireless local area networks (WLAN) is given. Finally, a patch module designed for 8-GHz operation is presented to show the versatility in frequency modularity. Experimental results of the fabricated antennas in free space, worn by a torso phantom and in bending conditions, validate the concept and prove that this type of modular design offers convenient, passive, low cost, and versatile system reconfigurabilities, which can benefit wearable applications. space, worn by a torso phantom and in bending conditions, validate the concept and prove that this type of modular design offers convenient, passive, low cost, and versatile system reconfigurabilities, which can benefit wearable applications.Shengjian Jammy Chen, Thomas Kaufmann, Damith Chinthana Ranasinghe, Christophe Fumeau

Wearable dual-band stripline-fed half-mode substrate-integrated cavity antenna

Published 19/02/2016A low-profile dual-band half-mode substrate-integrated cavity antenna with a fully shielded textile feeding mechanism is presented for wearable applications. The antenna operates at the lower and upper microwave industrial, scientific and medical bands. The cavity geometry is accurately defined with conducting thread through computerised embroidery. Design guidelines are developed for a practical realisation. Good agreement between simulated and measured results validates the proposed structure.S.P. Pinapati, T. Kaufmann, D.C. Ranasinghe, C. Fumeau

Effective-medium-cladded dielectric waveguides for terahertz waves

Terahertz integrated platforms with high efficiency are crucial in a broad range of applications including terahertz communications, radar, imaging and sensing. One key enabling technology is wideband interconnection. This work proposes substrate-less all-dielectric waveguides defined by an effective medium with a subwavelength hole array. These self-supporting structures are built solely into a single silicon wafer to minimize significant absorption in metals and dielectrics at terahertz frequencies. In a stark contrast to photonic crystal waveguides, the guiding mechanism is not based on a photonic bandgap but total internal reflections The waveguides are discussed in the context of terahertz communications that imposes stringent demands on performance. Experimental results show that the realized waveguides can cover the entire 260-400 GHz with single dominant modes in both orthogonal polarizations and an average measured attenuation around 0.05 dB/cm. Limited by the measurement setup, the maximum error-free data rate up to 30 Gbit/s is experimentally achieved at 335 GHz on a 3-cm waveguide. We further demonstrate the transmission of uncompressed 4K-resolution video across this waveguide. This waveguide platform promises integration of diverse active and passive components. Thus, we can foresee it as a potential candidate for the future terahertz integrated circuits, in analogy to photonic integrated circuits at optical frequencies. The proposed concept can potentially benefit integrated optics at large.Weijie Gao, Xiongbin Yu, Masayuki Fujita, Tadao Nagatsuma, Christophe Fumeaux and Withawat Withayachumnanku

Efficiency of a compact elliptical planar ultra-wideband antenna based on conductive polymers

Extent: 11p.A planar antenna for ultra-wideband (UWB) applications covering the 3.1–10.6 GHz range has been designed as a test bed for efficiency measurements of antennas manufactured using polymer conductors. Two types of conductive polymers, PEDOT and PPy (polypyrrole), with very different thicknesses and conductivities have been selected as conductors for the radiating elements. A comparison between measured radiation patterns of the conductive polymers and a copper reference antenna allows to estimate the conductor losses of the two types of conductive polymers. For a 158 μm thick PPy polymer, an efficiency of almost 80% can be observed over the whole UWB spectrum. For a 7 μm thick PEDOT layer, an average efficiency of 26.6% demonstrates, considering the room for improvement, the potential of this type of versatile materials as flexible printable alternative to conductive metallic paints. The paper demonstrates that, even though the PEDOT conductivity is an order of magnitude larger than that of PPy, the thicker PPy layer leads to much higher efficiency over the whole UWB frequency range. This result highlights that high efficiency can be achieved not only through high conductivity, but also through a sufficiently thick layer of conductive polymers.Thomas Kaufmann, Akhilesh Verma, Van-Tan Truong, Bo Weng, Roderick Shepherd, and Christophe Fumeau

Changing trends in end-stage renal disease patients with diabetes.

Worldwide, diabetes has become the most common cause of end-stage renal disease (ESRD), yet Swiss data are largely lacking. This observational study examined ESRD patients with diabetes mellitus (ESRD-DM) at end of 2009 and 2014. The prevalence and characteristics of ESRD-DM patients were collected in all dialysis facilities in the Canton of Vaud of Switzerland in 2009 and in 2014, and the 5-year mortality rate was assessed. A total of 107 and 140 ESRD-DM patients underwent dialysis at end of 2009 and 2014, respectively. Within the 5-year period a total of 167 incidental ESRD-DM patients required dialysis, corresponding to an estimated incidental rate of 0.84/1000 person-years in the diabetic population. In 2009, all patients with ESRD-DM underwent haemodialysis, decreasing to 96.2% in 2014, with 3.8% on peritoneal dialysis. Age, sex, body mass index, type of diabetes, duration of diabetes, cause of ESRD, dialysis duration, dialysis frequency, vascular access, and glycosylated haemoglobin levels did not differ between 2009 and 2014. In 2014, macrovascular comorbidity was reported more often than in 2009, but not amputations. Haemoglobin level decreased significantly from 117.9 g/l to 112.3 g/l. Calcium-containing phosphate binder and angiotensin-converting enzyme inhibitor use significantly decreased, whereas iron therapy significantly increased with time. The 5-year mortality rate was 61.7%. Five-year survivors were significantly younger and had a higher body mass index. The growing prevalence of ESRD-DM emphasises that prevention of chronic kidney disease and its progression should be a public health priority in Switzerland

Highly-Sensitive Thin Film THz Detector Based on Edge Metal-Semiconductor-Metal Junction

Terahertz (THz) detectors have been extensively studied for various applications such as security, wireless communication, and medical imaging. In case of metal-insulator-metal (MIM) tunnel junction THz detector, a small junction area is desirable because the detector response time can be shortened by reducing it. An edge metal-semiconductor-metal (EMSM) junction has been developed with a small junction area controlled precisely by the thicknesses of metal and semiconductor films. The voltage response of the EMSM THz detector shows the clear dependence on the polarization angle of incident THz wave and the responsivity is found to be very high (similar to 2,169 V/W) at 0.4 THz without any antenna and signal amplifier. The EMSM junction structure can be a new and efficient way of fabricating the nonlinear device THz detector with high cut-off frequency relying on extremely small junction area