Array Size Reduction for High-Rank LOS MIMO ULAs

In this paper we propose an extended LOS MIMO channel model, which considers an additional phase shifting term in the transmission path, and which provides the potential to improve channel conditioning significantly. We show that this phase shifting can, for example, be achieved by adding a dielectric material between the transmitting and receiving antennas, where the phase shift is dependent on the distance the waves travel in the medium. Using that distance as a design parameter we demonstrate that the optimal spacing between antenna elements of uniform linear arrays, achieving full spatial multiplexing, can be reduced compared with the well-known spacing criterion from previous investigations.Comment: Submitted to IEEE Wireless Communications Letter

Model Based Sensor System for Temperature Measurement in R744 Air Conditioning Systems

The goal is the development of a novel principle for the temperature acquisition of refrigerants in CO2 air conditioning systems. The new approach is based on measuring the temperature inside a pressure sensor, which is also needed in the system. On the basis of simulative investigations of different mounting conditions functional relations between measured and medium temperature will be derived.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838

Effect of a 6-week yoga intervention on swing mechanics during the golf swing:a feasibility study

Recent evidence suggests that participating in physical conditioning programmes can improve golf performance, however, the effectiveness of a yoga intervention has yet to be investigated. The aim of the current study was to investigate the effectiveness of a six-week yoga intervention on golf swing mechanics. Ten male golfers participated in the laboratory-based-study. Golf swing mechanics were collected from two testing sessions, before and after the six-week yoga intervention, using the Vicon motion capture system. Following the six-week yoga intervention, significant changes were observed between the yoga and control group in X-Factor (P ≤ 0.05) and a medium effect (d ≥ 0.50) observed. No significant changes (P > 0.05) and no effect (d < 0.20) were observed in the X-Factor stretch. Significant changes (P ≤ 0.05) and a medium effect (d > 0.50) were observed for the pelvis rotations following the yoga intervention, however, no differences were observed in torso rotations or hand velocities (P > 0.05). The findings of this feasibility study suggest that yoga may be a promising intervention in helping to improve golf swing mechanics, however, future research is required to confirm the effect of the use of yoga during the golf swing due to the sample size

Conditioning bounds for traveltime tomography in layered media

This paper revisits the problem of recovering a smooth, isotropic, layered wave speed profile from surface traveltime information. While it is classic knowledge that the diving (refracted) rays classically determine the wave speed in a weakly well-posed fashion via the Abel transform, we show in this paper that traveltimes of reflected rays do not contain enough information to recover the medium in a well-posed manner, regardless of the discretization. The counterpart of the Abel transform in the case of reflected rays is a Fredholm kernel of the first kind which is shown to have singular values that decay at least root-exponentially. Kinematically equivalent media are characterized in terms of a sequence of matching moments. This severe conditioning issue comes on top of the well-known rearrangement ambiguity due to low velocity zones. Numerical experiments in an ideal scenario show that a waveform-based model inversion code fits data accurately while converging to the wrong wave speed profile

Thermal analysis of Malaysian double storey housing - low/medium cost unit

Almost half of the total energy used today is consumed in buildings. In the tropical climate, air-conditioning a housing unit takes much of the energy bill. Malaysia is no exception. Malaysian double storey terrace housing is popular among developers and buyers. Surveys have shown that housing occupants are much dissatisfied with the thermal comfort and artificial cooling is often sought. The objective of this study is to assess the thermal comfort of the low and medium-cost double storey housing in the area surrounding Universiti Teknologi Malaysia. A simulation program using the Weighting Factor Method calculates the heat transfer interaction, temperature distribution, and PMV level in three types of housing units in relation to the size. Fanger's PMV model based on ISO Standard 7730 is used here because it accounts for all parameters that affect the thermal sensation of a human within its equation. Results showed that both the low and medium-cost housing units studied are out of the comfortable range described by ASHRAE Standard 55 with the units all complied with the local bylaws. In view of the uncertainties in energy supply, future housing units should consider natural ventilation as part of the passive energy management

Probing magnetic fields with multi-frequency polarized synchrotron emission

We investigate the problem of probing the local spatial structure of the magnetic field of the interstellar medium using multi-frequency polarized maps of the synchrotron emission at radio wavelengths. We focus in this paper on the three-dimensional reconstruction of the largest scales of the magnetic field, relying on the internal depolarization (due to differential Faraday rotation) of the emitting medium as a function of electromagnetic frequency. We argue that multi-band spectroscopy in the radio wavelengths, developed in the context of high-redshift extragalactic HI lines, can be a very useful probe of the 3D magnetic field structure of our Galaxy when combined with a Maximum A Posteriori reconstruction technique. When starting from a fair approximation of the magnetic field, we are able to recover the true one by using a linearized version of the corresponding inverse problem. The spectral analysis of this problem allows us to specify the best sampling strategy in electromagnetic frequency and predicts a spatially anisotropic distribution of posterior errors. The reconstruction method is illustrated for reference fields extracted from realistic magneto-hydrodynamical simulations

Enhanced selectivity of hydrogel-based molecularly imprinted polymers (HydroMIPs) following buffer conditioning.

We have investigated the effect of buffer solution composition and pH during the preparation, washing and re-loading phases within a family of acrylamide-based molecularly imprinted polymers (MIPs) for bovine haemoglobin (BHb), equine myoglobin (EMb) and bovine catalyse (BCat). We investigated water, phosphate buffer saline (PBS), tris(hydroxymethyl)aminomethane (Tris) buffer and succinate buffer. Throughout the study MIP selectivity was highest for acrylamide, followed by N-hydroxymethylacrylamide, and then N-iso-propylacrylamide MIPs. The selectivity of the MIPs when compared with the NIPs decreased depending on the buffer conditions and pH in the order of Tris>PBS>succinate. The Tris buffer provided optimum imprinting conditions at 50mM and pH 7.4, and MIP selectivities for the imprinting of BHb in polyacrylamide increased from an initial 8:1 to a 128:1 ratio. It was noted that the buffer conditions for the re-loading stage was important for determining MIP selectivity and the buffer conditions for the preparation stage was found to be less critical. We demonstrated that once MIPs are conditioned using Tris or PBS buffers (pH7.4) protein reloading in water should be avoided as negative effects on the MIP's imprinting capability results in low selectivities of 0.8:1. Furthermore, acidifying the pH of the buffer solution below pH 5.9 also has a negative impact on MIP selectivity especially for proteins with high isoelectric points. These buffer conditioning effects have also been successfully demonstrated in terms of MIP efficiency in real biological samples, namely plasma and serum

Plasma from Volunteers Breathing Helium Reduces Hypoxia-Induced Cell Damage in Human Endothelial Cells-Mechanisms of Remote Protection Against Hypoxia by Helium.

PurposeRemote ischemic preconditioning protects peripheral organs against prolonged ischemia/reperfusion injury via circulating protective factors. Preconditioning with helium protected healthy volunteers against postischemic endothelial dysfunction. We investigated whether plasma from helium-treated volunteers can protect human umbilical vein endothelial cells (HUVECs) against hypoxia in vitro through release of circulating of factors.MethodsHealthy male volunteers inhaled heliox (79% helium, 21% oxygen) or air for 30 min. Plasma was collected at baseline, directly after inhalation, 6 h and 24 h after start of the experiment. HUVECs were incubated with either 5% or 10% of the plasma for 1 or 2 h and subjected to enzymatically induced hypoxia. Cell damage was measured by LDH content. Furthermore, caveolin 1 (Cav-1), hypoxia-inducible factor (HIF1α), extracellular signal-regulated kinase (ERK)1/2, signal transducer and activator of transcription (STAT3) and endothelial nitric oxide synthase (eNOS) were determined.ResultsPrehypoxic exposure to 10% plasma obtained 6 h after helium inhalation decreased hypoxia-induced cell damage in HUVEC. Cav-1 knockdown in HUVEC abolished this effect.ConclusionsPlasma of healthy volunteers breathing helium protects HUVEC against hypoxic cell damage, possibly involving circulating Cav-1

Hypoxic pre-conditioning increases the infiltration of endothelial cells into scaffolds for dermal regeneration pre-seeded with mesenchymal stem cells.

Many therapies using mesenchymal stem cells (MSC) rely on their ability to produce and release paracrine signals with chemotactic and pro-angiogenic activity. These characteristics, however, are mostly studied under standard in vitro culture conditions. In contrast, various novel cell-based therapies imply pre-seeding MSC into bio-artificial scaffolds. Here we describe human bone marrow-derived MSC seeded in Integra matrices, a common type of scaffold for dermal regeneration (SDR). We show and measured the distribution of MSC within the SDR, where cells clearly establish physical interactions with the scaffold, exhibiting constant metabolic activity for at least 15 days. In the SDR, MSC secrete VEGF and SDF-1α and induce transwell migration of CD34(+) hematopoietic/endothelial progenitor cells, which is inhibited in the presence of a CXCR4/SDF-1α antagonist. MSC in SDR respond to hypoxia by altering levels of angiogenic signals such as Angiogenin, Serpin-1, uPA, and IL-8. Finally, we show that MSC-containing SDR that have been pre-incubated in hypoxia show higher infiltration of endothelial cells after implantation into immune deficient mice. Our data show that MSC are fully functional ex vivo when implanted into SDR. In addition, our results strongly support the notion of hypoxic pre-conditioning MSC-containing SDR, in order to promote angiogenesis in the wounds