In-plane Sensitive Electronic Speckle Pattern Interferometer using a Diffractive Holographic Optical Element

We describe a student project in electronic speckle pattern interferometry. The project includes holographic recording of diffraction gratings in thick, self-processing photopolymer layers made from off-the-shelf chemicals. The gratings are employed in a simple electronic speckle pattern interferometer to measure in-plane rotation

Contemporary analysis and architecture for a generic cloud-based sensor data management platform.

An increasing volume of data is being generated by sensors and smart devices deployed in different areas, often far from computing facilities such as data centres. These data can be difficult to gather and process using local computing infrastructure. This is due to cost and limited resources. Cloud computing provides scalable resources that are capable of addressing such problems. However, platform-independent methods of gathering and transmitting sensor data to Clouds are not widely available. This paper presents a state-of-the-art analysis of Cloud-based sensor monitoring and data gathering platforms. It discusses their strengths and weaknesses and reviews the current trends in this area. Informed by the analysis, the paper further proposes a generic conceptual architecture for achieving a platform-neutral Cloud-based sensor monitoring and data gathering platform. We also discuss the objectives, design decisions and the implementation considerations for the conceptual architecture.IC

Attenuated total reflectance infrared spectroelectrochemistry at a carbon particle electrode; unmediated redox control of a [NiFe]-hydrogenase solution

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.We report a versatile infrared spectroscopic method for studying redox chemistry of metalloproteins, and demonstrate for the first time electrochemically-induced changes to the active site of the regulatory [NiFe]-hydrogenase from Ralstonia eutropha. A carbon particle network working electrode allows control over a wide potential window without the need for solution mediators.EC/FP7/258600/EU/Understanding and Exploiting Biological Catalysts for Energy Cycling: Development of Infrared Spectroelectrochemistry for Studying Intermediates in Metalloenzyme Catalysis/ENERGYBIOCATALYSISDFG, EXC 314, Unifying Concepts in Catalysi

A trust label system for communicating trust in cloud services.

Cloud computing is rapidly changing the digital service landscape. A proliferation of Cloud providers has emerged, increasing the difficulty of consumer decisions. Trust issues have been identified as a factor holding back Cloud adoption. The risks and challenges inherent in the adoption of Cloud services are well recognised in the computing literature. In conjunction with these risks, the relative novelty of the online environment as a context for the provision of business services can increase consumer perceptions of uncertainty. This uncertainty is worsened in a Cloud context due to the lack of transparency, from the consumer perspective, into the service types, operational conditions and the quality of service offered by the diverse providers. Previous approaches failed to provide an appropriate medium for communicating trust and trustworthiness in Clouds. A new strategy is required to improve consumer confidence and trust in Cloud providers. This paper presents the operationalisation of a trust label system designed to communicate trust and trustworthiness in Cloud services. We describe the technical details and implementation of the trust label components. Based on a use case scenario, an initial evaluation was carried out to test its operations and its usefulness for increasing consumer trust in Cloud services.N/

Intrarenal Mas and AT(1) receptors play a role in mediating the excretory actions of renal interstitial angiotensin-(1-7) infusion in anaesthetized rats

New Findings What is the central question of this study? Dietary sodium manipulation alters the magnitude of angiotensin‐(1–7) [Ang‐(1–7)]‐induced natriuresis. The present study sought to determine whether this was related to relative changes in the activity of intrarenal Mas and/or AT1 receptors. What is the main finding and its importance? Angiotensin‐(1–7)‐induced diuresis and natriuresis is mediated by intrarenal Mas receptors. However, intrarenal AT1 receptor blockade also had an inhibitory effect on Ang‐(1–7)‐induced natriuresis and diuresis. Thus, Ang‐(1–7)‐induced increases in sodium and water excretion are dependent upon functional Mas and AT1 receptors. We investigated whether angiotensin‐(1–7) [Ang‐(1–7)]‐induced renal haemodynamic and excretory actions were solely dependent upon intrarenal Mas receptor activation or required functional angiotensin II type 1 (AT1) receptors. The renin–angiotensin system was enhanced in anaesthetized rats by prior manipulation of dietary sodium intake. Angiotensin‐(1–7) and AT1 and Mas receptor antagonists were infused into the kidney at the corticomedullary border. Mas receptor expression was measured in the kidney. Mean arterial pressure, urine flow and fractional sodium excretion were 93 ± 4 mmHg, 46.1 ± 15.7 μl min−1 kg−1 and 1.4 ± 0.3%, respectively, in the normal‐sodium group and 91 ± 2 mmHg, 19.1 ± 3.3 μl min−1 kg−1 and 0.7 ± 0.2%, respectively, in the low‐sodium group. Angiotensin‐(1–7) infusion had no effect on mean arterial pressure in rats receiving a normal‐sodium diet but decreased it by 4 ± 5% in rats receiving a low‐sodium diet (P < 0.05). Interstitial Ang‐(1–7) infusion increased urine flow twofold and fractional sodium excretion threefold (P < 0.05) in rats receiving a normal‐sodium diet and to a greater extent, approximately three‐ and fourfold, respectively, in rats receiving the low‐sodium diet (both P < 0.05). Angiotensin‐(1–7)‐induced increases in urine flow and fractional sodium excretion were absent in both dietary groups during intrarenal AT1 or Mas receptor inhibition after either losartan or A‐779, respectively. Thus, AT1 receptor activation, as well as Mas receptor activation, plays an essential role in mediating Ang‐(1–7)‐induced natriuresis and diuresis. Whether this is because Ang‐(1–7) partly antagonizes AT1 receptors or whether Ang‐(1–7)‐induced natriuresis is mediated through AT1–Mas receptor dimerization remains unclear

Superior Segment Facet Joint Violation During Instrumented Lumbar Fusion is Associated With Higher Reoperation Rates and Diminished Improvement in Quality of Life

Study Design: A retrospective cohort study at a single tertiary care center. Objective: To determine the impact of superior segment facet joint violation (FJV) during lumbar fusion on reoperation rates and quality of life (QOL). Summary of Background Data: Although lumbar fusion is an efficacious and durable treatment for numerous spinal pathologies, adjacent segment degeneration remains a serious complication. FJV has been suggested to alter load-bearing capability and potentially contribute to adjacent segment degeneration. Materials and Methods: Patients who underwent instrumented lumbar fusion surgery between 2009 and 2013 with postoperative computed tomography imaging were included. Patients were placed in the FJV group if either of the superior segment facet joints were compromised by the pedicle screw or rod. Patients with preserved facet joints were placed in the control group. Demographic, perioperative, QOL, and reoperation data were collected. QOL scores including the Pain Disability Questionnaire, Patient Health Questionnaire-9, and EuroQOL 5 Dimensions (EQ-5D) were acquired. Results: Of 240 patients included, 112 patients were found to have FJV and the remaining 128 patients were placed in the control group. One year following lumbar fusion, QOL outcomes and reoperation rates were similar between the FJV and control groups. At 2-year follow-up, patients in the FJV group were less likely to make a significant improvement in EQ-5D (P=0.041). Also, the reoperation rate in the FJV group was significantly higher than in the control group at 2 years (15.2% vs. 6.3%, respectively; P=0.024) and 3 years (19.6% vs. 9.4%, P=0.023). Multivariable logistic regression showed FJV to be an independent predictor of both (1) failing to make a significant improvement in EQ-5D (P=0.046) and (2) undergoing reoperation at both 2 and 3 years postoperatively (P=0.024 and 0.020, respectively). Conclusions: FJV was independently associated with a higher reoperation rate and diminished improvement in QOL

Chronic intermittent hypoxia increases rat sternohyoid muscle NADPH oxidase expression with attendant modest oxidative stress

Chronic intermittent hypoxia (CIH) causes upper airway muscle dysfunction. We hypothesized that the superoxide generating NADPH oxidase (NOX) is upregulated in CIH-exposed muscle causing oxidative stress. Adult male Wistar rats were exposed to intermittent hypoxia (5% O2 at the nadir for 90 s followed by 210 s of normoxia), for 8 h per day for 14 days. The effect of CIH exposure on the expression of NOX subunits, total myosin and 4-hydroxynonenal (4-HNE) protein adducts in sternohyoid muscle was determined by western blotting and densitometry. Sternohyoid protein free thiol and carbonyl group contents were determined by 1D electrophoresis using specific fluorophore probes. Aconitase and glutathione reductase activities were measured as indices of oxidative stress. HIF-1α content and key oxidative and glycolytic enzyme activities were determined. Contractile properties of sternohyoid muscle were determined ex vivo in the absence and presence of apocynin (putative NOX inhibitor). We observed an increase in NOX 2 and p47 phox expression in CIH-exposed sternohyoid muscle with decreased aconitase and glutathione reductase activities. There was no evidence, however, of increased lipid peroxidation or protein oxidation in CIH-exposed muscle. CIH exposure did not affect sternohyoid HIF-1α content or aldolase, lactate dehydrogenase, or glyceraldehyde-3-phosphate dehydrogenase activities. Citrate synthase activity was also unaffected by CIH exposure. Apocynin significantly increased sternohyoid force and power. We conclude that CIH exposure upregulates NOX expression in rat sternohyoid muscle with concomitant modest oxidative stress but it does not result in a HIF-1α-dependent increase in glycolytic enzyme activity. Constitutive NOX activity decreases sternohyoid force and power. Our results implicate NOX-dependent reactive oxygen species in CIH-induced upper airway muscle dysfunction which likely relates to redox modulation of key regulatory proteins in excitation-contraction coupling

Raman Spectroscopic Analysis of Human Skin Tissue Sections Ex-vivo: Evaluation of the Effects of Tissue Processing and Dewaxing

Raman spectroscopy coupled with K-means clustering analysis (KMCA) is employed to elucidate the biochemical structure of human skin tissue sections, and the effects of tissue processing. Both hand and thigh sections of human cadavers were analysed in their unprocessed and formalin fixed paraffin processed (FFPP) and subsequently dewaxed forms. In unprocessed sections, KMCA reveals clear differentiation of the stratum corneum, intermediate underlying epithelium and dermal layers for sections from both anatomical sites. The stratum corneum is seen to be relatively rich in lipidic content; the spectrum of the subjacent layers is strongly influenced by the presence of melanin, while that of the dermis is dominated by the characteristics of collagen. For a given anatomical site, little difference in layer structure and biochemistry is observed between samples from different cadavers. However, the hand and thigh sections are consistently differentiated for all cadavers, largely based on lipidic profiles. In dewaxed FFPP samples, while the stratum corneum, intermediate and dermal layers are clearly differentiated by KMCA of Raman maps of tissue sections, the lipidic contributions to the spectra are significantly reduced, with the result that respective skin layers from different anatomical sites become indistinguishable. While efficient at removing the fixing wax, the tissue processing also efficiently removes the structurally similar lipidic components of the skin layers. In studies of dermatological processes in which lipids play an important role, such as wound healing, dewaxed samples are therefore not appropriate. Removal of the lipids does however accentuate the spectral features of the cellular and protein components, which may be more appropriate for retrospective analysis of disease progression and biochemical analysis using tissue banks

Analysis of Human Skin Tissue by Raman Microspectroscopy: Dealing with the Background

Raman microspectroscopy is widely used for molecular characterisation of tissue samples. Nevertheless, when working in vitro on tissue sections, the presence of a broad background to the spectra remains problematic and its removal requires advanced methods for pre-processing of the data. To date, research efforts have been primarily devoted to development of techniques of statistical analysis to extract the relevant information contained in the spectra. However, few attempts have been made to understand the origin of the background and to improve the protocols used for the collection of Raman spectra that could lead to the reduction or elimination of the background. It has been demonstrated that measurement at 785nm in water immersion significantly reduces the Raman background of both pure biochemical components and tissue sections, associating the background at 785nm with a scattering phenomenon rather than fluorescence. It is however of interest to probe the dependence of the observed background and any time evolution normally associated with photobleaching of fluorophores, under dry and immersed conditions, on the source wavelength. Using 785nm or 660nm as source, extended exposure of dried skin tissue sections to the laser results in a time dependent reduction of the background present in the Raman spectra. When working in water immersion, the overall background as well as the evolution over time is greatly reduced and the background is seen to stabilise after ~20 seconds exposure. Using 532 nm or 473 nm as source for the examination of dried tissue sections, visible photodamage of the sample limits the laser power usable for the collection of spectra to 5 mW. Immersion of the tissue sections protects against photodamage and laser powers of up to 30 mW can be used without any visible damage. Under these conditions, the background is significantly reduced and good quality Raman spectra can be recorded. By adapting the protocol usually used for the collection of Raman spectra, this study clearly demonstrates that other approaches rather than mathematical manipulation of the data can be used to deal with the intrinsic background commonly observable. Notably, the dependence of the background and its time evolution under prolonged exposure on sample environment potentially sheds light on its origin as due to sample morphology (scattering) rather than chemical content (fluorescence). Overall, the study demonstrates that, in addition to reduced background, the photostability of the samples is significantly enhanced in an immersion geometry

In Vivo Flow Dynamics of the Total Cavopulmonary Connection from Three-dimensional Multislice Magnetic Resonance Imaging

Background. The total cavopulmonary connection (TCPC) design continues to be refined on the basis of flow analysis at the connection site. These refinements are of importance for myocardial energy conservation in the univentricular supported circulation. In vivo magnetic resonance phase contrast imaging provides semiquantitative flow visualization information. The purpose of this study was to understand the in vivo TCPC flow characteristics obtained by magnetic resonance phase contrast imaging and compare the results with our previous in vitro TCPC flow experiments in an effort to further refine TCPC surgical design. Methods. Twelve patients with TCPC underwent sedated three-dimensional, multislice magnetic resonance phase contrast imaging. Seven patients had intraatrial lateral tunnel TCPC and 5 had extracardiac TCPC. Results. In all patients in both groups a disordered flow pattern was observed in the inferior caval portion of the TCPC. Flow at the TCPC site appeared to be determined by connection geometry, being streamlined at the superior vena cava–pulmonary junction when the superior vena cava was offset and flared toward the left pulmonary artery. Without caval offset, intense swirling and dominance of superior vena caval flow was observed. In TCPC with bilateral superior vena cavae, the flow patterns observed included secondary vortices, a central stagnation point, and influx of the superior vena cava flow into the inferior caval conduit. A comparative analysis of in vivo flow and our previous in vitro flow data from glass model prototypes of TCPC demonstrated significant similarities in flow disturbances. Three-dimensional magnetic resonance phase contrast imaging in multiple coronal planes enabled a comprehensive semiquantitative flow analysis. The data are presented in traditional instantaneous images and in animated format for interactive display of the flow dynamics. Conclusions. Flow in the inferior caval portion of the TCPC is disordered, and the TCPC geometry determines flow characteristics