Performance Analysis of Smartphone-based Mobile Wi-Fi Hotspots Operating in a Congested Environment

In this work, we address the ubiquity of internet connections in smart cities by analyzing mobile Wi-Fi hotspots in terms of speed and energy efficiency in a congested Wi-Fi environment. We consider state-of-theart consumer smartphones in our work since they are the major devices in establishing mobile Wi-Fi hotspots nowadays. There are two main wireless connections in mobile Wi-Fi hotspots, the cellular connection and the Wi-Fi connection. It has been known that the speed of WiFi connections enormously supersedes the speed of cellular connections with the use of present technologies of each. In this work, we show that this well-known fact becomes controversial when establishing mobile Wi-Fi hotspots using smartphones in a nowadays typical congested Wi-Fi environment

Performance evaluation of a low cost series hybrid electric vehicle

The escalating amount of vehicles on the road has raised awareness to vehicular environmental impacts and sustainability; this has provided a stimulus for future mobility considerations. The conventional car may not meet future requirements regarding noise, emissions and energy consumption. There is a distinct lack of short-term alternative solutions that meet consumer requirements and has a potential for mass production. Furthermore, the internal combustion engine has been developed over 100 years and there may be some risk that the automotive companies choose to invest into the “wrong” alternative. This paper presents a development process in an attempt to find answer this dilemma. The first consideration is the vehicle performance criteria that take into account consumer expectations and operational/regulatory/environmental factors. Secondly, the drive train components are identified, most are commercially available, and are particular to these factors. Finally, a computer simulation isused to assess the performance of the vehicle, in comparison with the factors.The result of these investigations is a series hybrid electric vehicle that is recharged from the mains. The fuel consumption is four times better than that of a comparable car, but vehicle mass and cost have not increased significantly. The driving range of this vehicle is not limited to the battery capacity.This vehicle meets the consumer expectations as well as environmental issues and benefits with added driver comfort. Still being low-cost, it provides the potential for mass-production and thus reducing overall impacts on the environment

Spectroscopic & thermodynamic investigations of the physical basis of anhydrobiosis in caenorhabditis elegans dauer larvae

Anhydrobiotic organisms have the remarkable ability to lose extensive amounts of body water and survive in an ametabolic, suspended animation state. Distributed to various taxa of life, these organisms have evolved strategies to efficiently protect their cell membranes and proteins against extreme water loss. At the molecular level, a variety of mutually non-exclusive mechanisms have been proposed to account particularly for preserving the integrity of the cell membranes in the desiccated state. Recently, it has been shown that the dauer larva of the nematode Caenorhabditis elegans is anhydrobiotic and accumulates high amounts of trehalose during preparation for harsh desiccation (preconditioning), thereby allowing for a reversible desiccation / rehydration cycle. Here, we have used this genetic model to study the biophysical manifestations of anhydrobiosis and show that, in addition to trehalose accumulation, the dauer larvae exhibit a systemic chemical response upon preconditioning by dramatically reducing their phosphatidylcholine (PC) content. The C. elegans strain daf-2 was chosen for these studies, because it forms a constitutive dauer state under appropriate growth conditions. Using complementary approaches such as chemical analysis, time-resolved FTIR-spectroscopy, Langmuir-Blodgett monolayers, and fluorescence spectroscopy, it is shown that this chemical adaptation of the phospholipid (PL) composition has key consequences for their interaction with trehalose. Infrared-spectroscopic experiments were designed and automated to particularly address structural changes during fast hydration transients. Importantly, the coupling of headgroup hydration to acyl chain order at low humidity was found to be altered on the environmentally relevant time scale of seconds. PLs from preconditioned larvae with reduced PC content exhibit a higher trehalose affinity, a stronger hydration-induced gain in acyl chain free volume, and a wider spread of structural relaxation rates during lyotropic transitions and sub- headgroup H-bond interactions as compared to PLs from non-preconditioned larvae. The effects are related to the intrinsically different hydration properties of PC and phosphatidylethanolamine (PE) headgroups, and lead to a larger hydration-dependent rearrangement of trehalose-mediated H-bond network in PLs from preconditioned larvae. This results in a lipid compressibility modulus of ∼0.5 mN/m and 1.2 mN/m for PLs derived from preconditioned and non-preconditioned larvae, respectively. The ensemble of these changes evidences a genetically controlled chemical tuning of the native lipid composition of a true anhydrobiote to functionally interact with a ubiquitous protective disaccharide. The biological relevance of this adaptation is the preservation of plasma membrane integrity by relieving mechanical strain from desiccated trehalose- containing cells during fast rehydration. Finally, the thermo-tropic lipid phase behavior was studied by temperature-dependent ATR-FTIR and fluorescence spectroscopy of LAURDAN-labeled PLs. The results show that the adaptation to drought, which is accomplished to a significant part by the reduction of the PC content, relies on reducing thermo-tropic and enhancing lyotropic phase transitions. The data are interpreted on a molecular level emphasizing the influence of trehalose on the lipid phase transition under biologically relevant conditions by a detailed analysis of the lipid C=O H-bond environment. The salient feature of the deduced model is a dynamic interaction of trehalose at the PL headgroup region. It is proposed here that the location of trehalose is changed from a more peripheral to a more sub-headgroup-associated position. This appears to be particularly pronounced in PLs from preconditioned worms. The sugar slides deeper into the inter-headgroup space during hydration and thereby supports a quick lateral expansion such that membranes can more readily adapt to the volume changes in the swelling biological material at reduced humidity. The data show that the nature of the headgroup is crucial for its interaction with trehalose and there is no general mechanism by which the sugar affects lipidic phase transitions. The intercalation into a phosphatidylethanolamine-rich membrane appears to be unique. In this case, neither the phase transition temperature nor its width is affected by the protective sugar, whereas strong effects on these parameters were observed with other model lipids. With respect to membrane preservation, desiccation tolerance may be largely dependent on reducing phosphatidylcholine and increasing the phsophatidylethanolamine content in order to optimize trehalose headgroup interactions. As a consequence, fast mechanical adaptation of cell membranes to hydration-induced strain can be realized

An inertial coupled marine power generator for small boats

This paper proposes a device to harvest energy from the vertical motion of small boats and yachts. The device comprises a sprung mass coupled to an electrical generator through a ball screw. The mathematical equations describing the dynamics of the system are derived. The equations are used to determine the optimum device parameters, namely its mass, spring constant, ball screw lead, within practical constraints. Simulation results are presented to determine the maximum power that can be generated and the optimum load resistance as a function of boat vibration frequency

Interaction of Retinol with HSA using Spectroscopic Techniques

The interaction between retinol and HSA has been investigated using UV-absorption spectrophotometry, fluorescence spectroscopy and Fourier Transform Infrared (FT-IR) spectroscopy.UV-absorption spectrophotometry showed an increase in the absorption intensity with increasing the molecular ratios of retinol to HSA, it is found that the value of the binding constant is estimated to be1.7176×102 M-1. FTIR spectroscopy is used in the mid infrared region with Fourier self deconvolution, second derivative, difference spectra, peak picking and curve fitting were used to determine the effect of Retinol on the protein secondary structure in the amides I, II and Ill regions. Analysis of FTIR absorbance spectra is found that the intensity of the absorption bands increased with increasing the molecular ratios of retinol, however from the deconvoluted and curve fitted spectra found that the absorbance intensity for α-helix decreases relative to β-sheets, this decrease in intensity is related to the formation of H- bonding in the complex molecules

Interaction of the Testosterone with Bovine Serum Albumin (BSA): UV-Visible Absorption Spectroscopy

The molecular interactions between BSA and Testosterone have been successfully investigated. The absorption, distribution and metabolism of many molecules can be altered based on their affinity to BSA. BSA is often increases the apparent solubility of hydrophobic ligands in plasma and modulate their delivery to cells. In this study, the interaction between Testosterone and BSA has been investigated using UV- absorption spectrophotometry and fluorescence spectroscopy to determine the binding constant. From UV- absorption spectrophotometry which showed a decreasing in the absorption intensity with increasing of the molecular ratios of testosterone to BSA, it is found that the value of the binding constant of testosterone to BSA, K equals 0.415*103 M-1 at 293 K. While from the Fluorescence spectroscopy there was a quenching in the intensity with increasing of the molecular ratios of testosterone to BSA and it gave the same value of the binding constant as uv-absorption spectroscopy.This work is supported by the German Research Foundation DFG grant no. DR228/24-

Comparative studies on the interactions between human serum albumin, bovine serum albumin and cholesterol: ftir and fluorescence spectroscopy

The interaction of the human serum albumin (HSA), bovine serum albumin (BSA) with cholesterol has been investigated. The basic binding interaction was studied by FTIR and fluorescence spectroscopy. From spectral analysis cholesterol showed a strong ability to quench the intrinsic fluorescence of HSA and BSA through a static quenching mechanism. The binding constant (k) between HSA and cholesterol is estimated to be K=2.14 × 103 M-1 at 293 K while between BSA and cholesterol is estimated to be K=.1.12 × 103 M-1 at the same temperature. FTIR spectroscopy with Fourier self-deconvolution technique was used to determine the protein secondary structure and cholesterol binding mechanisms. The observed spectral changes indicate a higher percentage of H-bonding between cholesterol and -helix compared to the percentage of H-bonding to cholesterol and -sheets.This work is supported by the German Research Foundation DFG grant No. DR228/24-

Nefrología Diagnóstica e Intervencionista: extensión en España y beneficios en la atención al paciente renal

En nuestro trabajo queremos evaluar la práctica y la formación de la nefrología diagnóstica e intervencionista en España, así mismo, evaluar la seguridad de los procedimientos realizados por nefrólogos y valorar el beneficio obtenido cuando la práctica de la nefrología diagnóstica e intervencionista esté realizada por nefrólogos entrenados. Para la realización de este estudio, se ha elaborado un formulario para recoger los datos de toda la información relacionada con la actividad de la nefrología diagnóstica e intervencionista realizada en los hospitales en España en el último año, y se ha enviado a los servicios correspondientes a través de la secretaria de la Sociedad Española de Nefrología, se ha aceptado una respuesta por Servicio de Nefrología. Encontramos cierta deficiencia en la actividad de la nefrología diagnóstica e intervencionista, tanto en formación como en solidez en los centros de nefrología en España, aunque se comprueba la adecuada seguridad en los procedimientos realizados por nefrólogos, y el efecto positivo en la atención a los pacientes renale

Enhanced Position Verification for VANETs using Subjective Logic

The integrity of messages in vehicular ad-hoc networks has been extensively studied by the research community, resulting in the IEEE~1609.2 standard, which provides typical integrity guarantees. However, the correctness of message contents is still one of the main challenges of applying dependable and secure vehicular ad-hoc networks. One important use case is the validity of position information contained in messages: position verification mechanisms have been proposed in the literature to provide this functionality. A more general approach to validate such information is by applying misbehavior detection mechanisms. In this paper, we consider misbehavior detection by enhancing two position verification mechanisms and fusing their results in a generalized framework using subjective logic. We conduct extensive simulations using VEINS to study the impact of traffic density, as well as several types of attackers and fractions of attackers on our mechanisms. The obtained results show the proposed framework can validate position information as effectively as existing approaches in the literature, without tailoring the framework specifically for this use case.Comment: 7 pages, 18 figures, corrected version of a paper submitted to 2016 IEEE 84th Vehicular Technology Conference (VTC2016-Fall): revised the way an opinion is created with eART, and re-did the experiments (uploaded here as correction in agreement with TPC Chairs