4-bit SiGe phase shifter using distributed active switches and variable gain amplifier for x-band phased array applications

This paper presents a 4-bit digitally controlled phase shifter for X-band (8-12.5 GHz) phased-arrays, implemented in 0.25-mu m SiGe BiCMOS process. Distributed active switches are utilized in first three bits. On-chip inductances are used to provide 22.5 degrees phase shift steps. The placement and the geometry of these inductances are optimized for minimum phase error and insertion loss. In order to compensate the gain variations of this stage, a single stage variable gain amplifier is used. The fourth bit which provides 0/180 degrees phase shift is obtained in third amplification stage, with switching between common base - common emitter configuration. With utilization of this technique overall phase error is significantly decreased and overall gain is increased. The phase shifter achieves 7dB gain with 3 dB of gain error. 360 degrees phase shift is achieved in 4 bit resolution with a phase error of 0.5 degrees at center frequency of 10GHz, and maximum 22 degrees phase error in 4.5 GHz bandwidth. The chip size is 2150 mu m x 1040 mu m including the bondpads. These performance parameters are comparable with the state of the art using similar technology

The effects of rivaroxaban, an oral anticoagulant, on human IVD primary cultures

Introduction: The present study aimed to investigate the potential effects of rivaroxaban, an oral anticoagulant that inhibits the effects of factor Xa, on intact intervertebral disc tissue cells and the extracellular matrix (ECM). Material and methods: Rivaroxaban was applied to primary human cell cultures prepared from tissues of the intervertebral disc. Comparative molecular analyses were performed on non-drug-treated control group samples. Descriptive statistics were presented as the mean +/- standard deviation. An analysis of variance test was performed to determine whether there were significant differences in the mean across the groups. When differences across groups were observed, Tukey's honestly significant difference post-hoc test was used for multiple pairwise comparisons. The significance of the obtained data was determined statistically. The alpha significance value was < 0.05. Results: The cells in the control group and in the rivaroxaban-treated group were viable, healthy, and proliferated (p < 0.05). However, the expression levels of the chondroadherin gene (CHAD), cartilage oligo matrix protein (COMP), matrix metalloproteinase (MMP)-13, and MMP-19 genes were changed (p < 0.05). Conclusions: Although rivaroxaban does not suppress cell proliferation due to morphological, biological, and biochemical changes in the intervertebral disc tissue, it may change the expression of genes that are related to ECM maintenance

Active positive sloped equalizer for x-band SiGe BiCMOS phased array applications

This work presents an active equalizer circuit with positive gain slope at X-Band (8 - 12 GHz). Compared to passive examples, the active equalizer realized better filter and impedance characteristics in frequency of interest with increased functionality for a single amplification stage. It achieved close to 10 dB of peak gain, a + 1.13 dB/GHz gain slope with 2.8 dB NF by utilizing cascode topology. The design reaches a -1.5 dBm input-referred compression point (input-P1dB) while consuming 46 mW of power. To the best of authors’ knowledge, the presented work achieves the best on-chip gain, a gain slope and NF performance in the literature as an equalizer that utilizes SiGe BiCMOS technology

Effects of etanercept, a tumor necrosis factor receptor fusion protein, on primary cell cultures prepared from intact human intervertebral disc tissue

The aim of the present study was to investigate the effects of etanercept (ETA), a tumor necrosis factor (TNF) inhibitor, on human cell cultures prepared from intact intervertebral disc tissue. ETA is used as a treatment for cases of rheumatoid arthritis, psoriatic arthritis, axial spondyloarthritis and ankylosing spondylitis accompanied by moderate or severe joint pain. ETA was applied to primary cell cultures [annulus fibrosus and nucleus pulposus (NP) from intact intervertebral disc tissue]. Cell cultures without ETA treatment served as the control group. Morphological and quantitative molecular analyses of the two groups were performed. The number of viable cells and cell proliferation decreased in the ETA-treated cultures as compared with those in the control group. Furthermore, in the treatment group, the chondroadherin gene, an NP-specific marker, was not expressed after 24 h. By contrast, the cartilage oligo matrix protein was expressed 24, 48 and 72 h post-ETA treatment, while its expression was significantly lower than that in the control group. In addition, the expression of interleukin-1 beta, as well as matrix metallopeptidase-7 and -19, was markedly decreased. Overall, the cell proliferation and gene expression in the ETA-treated cells were significantly different from those in the control group (P<0.05). These results suggest that the treatment duration and dosage of TNF inhibitors, which are used to suppress active inflammation, should be considered in the clinical setting. These biological agents may delay the healing of intervertebral disc tissue damage by slowing cell proliferation and altering gene expression via anabolic and catabolic pathways

An x-band 6-bit active phase shifter

This paper presents a 6-bit active phase shifter using a new vector-sum method for X-band (8-12 GHz) phased arrays in 0.13 mu m SiGe BiCMOS process. An RC filter is used to generate two orthogonal vectors which are then fed into four VGAs, two using the common-base and two using the common-emitter topology. This generates 4 vectors of 0 degrees, 90 degrees, 180 degrees and 270 degrees which are scaled and added by varying the gains of the VGAs to generate any phase between 0-360 degrees. The gains of the VGAs are adjusted with analog voltage control using the current-steering method. The outputs of the VGAs are connected together with a common load in order to add the vectors in current-domain. The phase shifter achieves < 5.6 degrees RMS phase error over 8-12 GHz and < 3.1 degrees RMS phase error over 9-11 GHz. The phase shifter has a power consumption of 16.6 mW from a 2V supply. The chip size is 850 mu m x 532 mu m including the probing pads. These performance parameters are comparable with the state of the art of the technology in literature

New CagL amino acid polymorphism patterns of helicobacter pylori in peptic ulcer and non-ulcer dyspepsia

Background and Objectives: Helicobacter pylori infection is associated with chronic gastritis, ulcers, and gastric cancer. The H. pylori Type 4 secretion system (T4SS) translocates the CagA protein into host cells and plays an essential role in initiating gastric carcinogenesis. The CagL protein is a component of the T4SS. CagL amino acid polymorphisms are correlated with clinical outcomes. We aimed to study the association between CagL amino acid polymorphisms and peptic ulcer disease (PUD) and non-ulcer dyspepsia (NUD). Materials and Methods: A total of 99 patients (PUD, 46; NUD, 53) were enrolled and screened for H. pylori by qPCR from antrum biopsy samples. The amino acid polymorphisms of CagL were analyzed using DNA sequencing, followed by the MAFFT sequence alignment program to match the amino acid sequences. Results: Antrum biopsy samples from 70 out of 99 (70.7%) patients were found to be H. pylori DNA-positive. A positive band for cagL was detected in 42 out of 70 samples (PUD, 23; NUD, 19), and following this, these 42 samples were sequenced. In total, 27 different polymorphisms were determined. We determined three CagL amino acid polymorphism combinations, which were determined to be associated with PUD and NUD. Pattern 1 (K35/N122/V134/T175/R194/E210) was only detected in PUD patient samples and was related to a 1.35-fold risk (p = 0.02). Patterns 2 (V41/I134) and 3 (V41/K122/A171/I174) were found only in NUD patient samples and were linked to a 1.26-fold increased risk (p = 0.03). Conclusions: We observed three new patterns associated with PUD and NUD. Pattern 1 is related to PUD, and the other two patterns (Patterns 2 and 3) are related to NUD. The patterns that we identified include the remote polymorphisms of the CagL protein, which is a new approach. These patterns may help to understand the course of H. pylori infection.Istanbul Aydin University Scientific Research Projects Uni

A wideband low noise SiGe medium power amplifier for x-band phased array applications

This paper presents a Medium Power Amplifier (MPA) for X-Band Phased Array RADAR applications in 0.25 mu m SiGe technology. The MPA is designed such that it achieves high output power and low noise simultaneously that enables its use in Transmitter/ Receiver (T/R) core module as a Low Noise Amplifier (LNA). The MPA achieves 23.6dB peak gain and 17.3dB maximum output power at 10GHz with a power consumption of 190mW. Its input and output is matched in a 7 GHz of bandwidth, while its mean Noise Figure (NF) is about 3dB throughout the defined bandwidth. According to authors' knowledge, this work presents state-of-the-art wideband MPA performances in literature, with 7GHz of operational bandwidth and 17.3dBm output power

A SiGe BiCMOS bypass low-noise amplifier for x-band phased array RADARs

This paper presents a bypass low noise amplifier (LNA) for X-band phased array applications in 0.25μm SiGe BiCMOS technology. The trade-off between gain and bypass modes is considered to achieve high gain as well as low noise figure for gain mode while maintaining reasonable insertion loss with high power handling capability in bypass mode. In gain mode, the LNA achieves a measured gain of 17-14.2 dB and a noise figure of 1.75-1.95 dB over the 8-12 GHz band while consuming 27.4mW of DC-power. The measured input-referred I-dB compression point (IP 1dB ) is -3.9 dBm at 10 GHz. When operating in bypass mode, the measured insertion loss is 6.5-5.95 dB over the entire X-band with the measured IP 1dB of 15.1 dBm at 10 GHz, and it dissipates only 1μW power. Thanks to the bypassing technique, an increase of about 19 dB is achieved for IP 1dB in bypass mode compare to the gain mode. The measured return losses are better than 10 dB for both operating modes over whole X-band. The effective chip area excluding the pads is 0.3 mm 2

A wideband high isolation CMOS T/R switch for x-band phased array radar systems

This paper presents an SPDT switch which is designed to operate at 8-12 GHz frequency range (X-Band), as a sub module of the front end circuit of a phased array radar. The switch distinguishes itself from its counterparts with its larger frequency range and higher isolation that is uniformly distributed over its bandwidth. It is fabricated using 0.25 mu m SiGe BiCMOS technology of IHP Microelectronics (Germany). As a new technique, shunt inductors are placed next to shunt transistors in order to improve trade-off between insertion loss and isolation. It has isolation higher than 30 dB in entire band, input referred 1dB compression point is 27.6 dBm, insertion loss is between 2.7-4.1 dB, input and output referred return losses are better than 11 dB in the frequency range of 8-12 Gliz