Six-port precision directional coupler

A design for a six-port, high phase and amplitude balance, stripline coupler is presented. Both the predicted and the measured performance of a hardware prototype show phase and amplitude balance better than 0.2 dB and 0.9 at the design frequency of 2.46 GHz when fabricated on an FR-4 substrate

Wideband 0.18µm CMOS VCO Using Active Inductor with Negative Resistance

This paper presents a wideband voltage controlled oscillator topology based on an active inductor generating negative resistance. The proposed architecture covers a frequency band between 1.325 GHz - 2.15 GHz with average in-band phase noise of -86 dBc/Hz at 1 MHz offset from the carrier frequency. Power consumption of the oscillator core is 28 mW from a 1.8 V supply. The circuit has been simulated in Eldo RF (Design Architect IC, Mentor Graphics) using UMC 0.18 µm 1P6M Salicide RF CMOS model libraries

Physical component performance degradation detection based on error probability analysis

The detection and diagnosis of physical layer faults at system level in communications systems remains problematic. This paper presents a cross layer fault detection scheme, suitable for implementation at higher levels in a communications system,with the ability to detect and diagnose the cause of physical layer failure which results in impaired performance. It is based on the distribution of symbol error frequency and the probability of error of the underlying modulation scheme used in the communications system. With this knowledge, a simple counting algorithm is proposed as a diagnostic tool to implement the methodology

Wideband 0.18µm CMOS VCO Using Active Inductor with Negative Resistance

This paper presents a wideband voltage controlled oscillator topology based on an active inductor generating negative resistance. The proposed architecture covers a frequency band between 1.325 GHz - 2.15 GHz with average in-band phase noise of -86 dBc/Hz at 1 MHz offset from the carrier frequency. Power consumption of the oscillator core is 28 mW from a 1.8 V supply. The circuit has been simulated in Eldo RF (Design Architect IC, Mentor Graphics) using UMC 0.18 µm 1P6M Salicide RF CMOS model libraries

Low cost experimental software defined radio system

This paper documents the design of a low cost experimental SDR Platform as a research tool. In order to keep costs to a minimum and provide the maximum flexibility a processor-less architecture is chosen. All signal processing is carried out using a standard notebook computer. The platform consists of four hardware elements. These are baseband transmitter board, baseband receiver board, RF transmitter board and RF receiver board. The baseband transmitter board consists of a USB 2.0 interface and two 16-bit DACs. The baseband receiver board consists of a USB 2.0 interface and two 16-bit ADCs. The transmitter RF board consists of a direct conversion modulator, local oscillator, variable gain RF amplifier and power amplifier. The receiver board consists of a low noise amplifier, a direct conversion down-converter with gain control and a local oscillator

Elevated ACKR2 expression is a common feature of inflammatory arthropathies

Objectives. Chemokines are essential contributors to leucocyte accumulation at sites of inflammatory pathology. Interfering with chemokine or chemokine receptor function therefore represents a plausible therapeutic option. However, our currently limited understanding of chemokine orchestration of inflammatory responses means that such therapies have not yet been fully developed. We have a particular interest in the family of atypical chemokine receptors that fine-tune, or resolve, chemokine-driven responses. In particular we are interested in atypical chemokine receptor 2 (ACKR2), which is a scavenging receptor for inflammatory CC-chemokines and that therefore helps to resolve in vivo inflammatory responses. The objective of the current study was to examine ACKR2 expression in common arthropathies. Methods. ACKR2 expression was measured by a combination of qPCR and immuno-histochemistry. In addition, circulating cytokine and chemokine levels in patient plasma were assessed using multiplexing approaches. Results. Expression of ACKR2 was elevated on peripheral blood cells as well as on leucocytes and stromal cells in synovial tissue. Expression on peripheral blood leucocytes correlated with, and could be regulated by, circulating cytokines with particularly strong associations being seen with IL-6 and hepatocyte growth factor. In addition, expression within the synovium was coincident with aggregates of lymphocytes, potentially atopic follicles and sites of high inflammatory chemokine expression. Similarly increased levels of ACKR2 have been reported in psoriasis and SSc. Conclusion. Our data clearly show increased ACKR2 in a variety of arthropathies and taking into account our, and others’, previous data we now propose that elevated ACKR2 expression is a common feature of inflammatory pathologies

Hardware implementation of a versatile low-cost mixed-signal platform for SDR experimentation

This paper presents the design of a reconfigurable mixedsignal platform used in the Software Defined Radio context.It is a single board part of a pre-existing modular system operating from 1.6 to 2.5 GHz that supports GSM1800,DCS1800, PCS1900, UMTS-FDD, UMTS-TDD and 802.11b standards. Its purpose is to facilitate configuration and data exchange between a computer and an RF transceiver. Technical choices, design and overall performances of the prototype are discussed

Software engine development for SDR

This paper focuses on the development of the software engine for an SDR hardware platform [1][2]. This SDR hardware system operates across the frequency band from 1.6GHz to 2.5GHz with the capability to support the GSM1800, PCS 1900, UMTS-FDD, UMTS-TDD and 802.11b standards. It consists of TX/RX RF front-ends, data converters and the USB 2.0 PHY interface

Exchange of polar lipids from adults to neonates in \u3ci\u3eDaphnia magna\u3c/i\u3e: Perturbations in sphingomyelin allocation by dietary lipids and environmental toxicants

Because xenosensing nuclear receptors are also lipid sensors that regulate lipid allocation, we hypothesized that toxicant-induced modulation of HR96 activity would alter lipid profiles and the balance between adult survival and neonate production following exposure in Daphnia magna. Adult daphnids were exposed to unsaturated fatty acid- and toxicant- activators or inhibitors of HR96 and later starved to test whether chemical exposure altered allocation toward survival or reproduction. The HR96 activators, linoleic acid and atrazine, decreased reproduction as expected with concomitant changes in the expression of HR96 regulated genes such as magro. The HR96 inhibitors, docosahexaenoic acid (DHA) and triclosan, increased reproduction or neonate starvation survival, respectively. However, pre-exposure to triclosan increased in neonate survival at the expense of reproductive maturation. Lipidomic analysis revealed that sphingomyelins (SM) are predominantly found in neonates and therefore we propose are important in development. DHA and triclosan increased neonatal SM, consistent with HR96’s regulation of Niemann-Pick genes. While DHA altered expression of magro, Niemann-Pick 1b, mannosidase, and other HR96-regulated genes as expected, triclosan primarily perturbed sphingomyelinase and mannosidase expression indicating different but potentially overlapping mechanisms for perturbing SM. Overall, SM appears to be a key lipid in Daphnia maturation and further support was provided by carmofur, which inhibits sphingomyelin/ceramide metabolism and in turn severely represses Daphnia maturation and initial brood production. In conclusion, toxicants can perturb lipid allocation and in turn impair development and reproduction

Ultraviolet Fe II Emission in Fainter Quasars: Luminosity Dependences, and the Influence of Environments

We investigate the strength of ultraviolet Fe II emission in fainter quasars com- pared with brighter quasars for 1.0 :( z :( 1.8, using the SDSS (Sloan Digital Sky Survey) DR7QSO catalogue and spectra of Schneider et al., and the SFQS (SDSS Faint Quasar Survey) catalogue and spectra of Jiang et al. We quantify the strength of the UV Fe II emission using the W 2400 equivalent width of Weymann et al., which is defined between two rest-frame continuum windows at 2240–2255 and 2665–2695 ˚A. The main results are the following. (1) We find that for W 2400 2: 25 ˚A there is a universal (i.e. for quasars in general) strengthening of W 2400 with decreasing intrinsic luminosity, L3000. (2) In conjunction with previous work by Clowes et al., we find that there is a further, differential, strengthening of W 2400 with decreasing L3000 for those quasars that are members of Large Quasar Groups (LQGs). (3) We find that increasingly strong W 2400 tends to be associated with decreasing FWHM of the neighbouring Mg II λ2798 broad emission line. (4) We suggest that the dependence of W 2400 on L3000 arises from Lyα fluorescence. (5) We find that stronger W 2400 tends to be associated with smaller virial estimates from Shen et al. of the mass of the central black hole, by a factor ∼ 2 between the ultrastrong emitters and the weak. Stronger W 2400 emission would correspond to smaller black holes that are still growing. The differential effect for LQG members might then arise from preferentially younger quasars in the LQG environments