Fully Integrated 24-GHz 1TX-2RX Transceiver for Compact FMCW Radar Applications

A fully integrated 24-GHz radar transceiver with one transmitter (TX) and two receivers (RXs) for compact frequency modulated continuous wave (FMCW) radar applications is here presented. The FMCW synthesizer was realized using a fractional-N phase-locked loop (PLL) and programmable chirp generator, which are completely integrated in the proposed transceiver. The measured output phase noise of the synthesizer is -80 dBc/Hz at 100 kHz offset. The TX consists of a three-bit bridged t-type attenuator for gain control, a two-stage drive amplifier (DA) and a one-stage power amplifier (PA). The TX chain provides an output power of 13 dBm while achieving <0.5 dB output power variation within the range of 24 to 24.25 GHz. The RX with a direct conversion I-Q structure is composed of a two-stage low noise amplifier (LNA), I-Q generator, mixer, transimpedance amplifier (TIA), a two-stage biquad band pass filter (BPF), and a differential-to-single (DTS) amplifier. The TIA and the BPF employ a DC offset cancellation (DCOC) circuit to suppress the strong reflection signal and TX-RX leakage. The RX chain exhibits an overall gain of 100 dB. The proposed radar transceiver is fabricated using a 65 nm CMOS technology. The transceiver consumes 220 mW from a 1 V supply voltage and has 4.84 mm2 die size including all pads. The prototype FMCW radar is realized with the proposed transceiver and Yagi antenna to verify the radar functionality, such as the distance and angle of targets.

A Wideband True Time Delay Circuit Using 0.25 µm GaN HEMT Technology

This paper presents a wideband 4-bit true time delay IC using a 0.25 μm GaN HEMT (High-Electron-Mobility Transistor) process for the beam-squint-free phased array antennas. The true time delay IC is implemented with a switched path circuit topology using DPDT (Double Pole Double Throw) with no shunt transistor in the inter-stages to improve the bandwidth and SPDT (Single Pole Single Throw) switches at the input and the output ports. The delay lines are implemented with CLC π-networks with the lumped element to ensure a compact chip size. A negative voltage generator and an SPI controller are implemented in the PCB (Printed Circuit Board) due to the lack of digital control logic in GaN technology. A maximum time delay of ~182 ps with a time delay resolution of 10.5 ps is achieved at DC-6 GHz. The RMS (Root Mean Square) time delay and amplitude error are <5 ps and <0.6 dB, respectively. The measured insertion loss is <6.8 dB and the input and output return losses are >10 dB at DC-6 GHz. The current consumption is nearly zero with a 3.3 V supply. The chip size including pads is 2.45 × 1.75 mm2. To the authors' knowledge, this is the first demonstration of a true time delay IC using GaN HEMT technology.

A Multimode 28 GHz CMOS Fully Differential Beamforming IC for Phased Array Transceivers

A 28 GHz fully differential eight-channel beamforming IC (BFIC) with multimode operations is implemented in 65 nm CMOS technology for use in phased array transceivers. The BFIC has an adjustable gain and phase control on each channel to achieve fine beam steering and beam pattern. The BFIC has eight differential beamforming channels each consisting of the two-stage bi-directional amplifier with a precise gain control circuit, a six-bit phase shifter, a three-bit digital step attenuator, and a tuning bit for amplitude and phase variation compensation. The Tx and Rx mode overall gains of the differential eight-channel BFIC are around 11 dB and 9 dB, respectively, at 27.0-29.5 GHz. The return losses of the Tx mode and Rx mode are >10 dB at 27.0-29.5 GHz. The maximum phase of 354° with a phase resolution of 5.6° and the maximum attenuation of 31 dB, including the gain control bits with an attenuation resolution of 1 dB, is achieved at 27.0-29.5 GHz. The root mean square (RMS) phase and amplitude errors are <3.2° and <0.6 dB at 27.0-29.5 GHz, respectively. The chip size is 3.0 × 3.5 mm², including pads, and Tx mode current consumption is 580 mA at 2.5 V supply voltage.

WHO informal consultation on revision of guidelines on evaluation of similar biotherapeutic products, virtual meeting, 30 June – 2 July 2021

The WHO informal consultation was held to promote the revision of WHO guidelines on evaluation of similar biotherapeutic products (SBPs) adopted by the Expert Committee on Biological Standardization (ECBS) in 2009. It was agreed in the past consultations that the evaluation principles in the guidelines are still valid, but a review was recommended to provide more clarity and case-by-case flexibility. The opportunity was therefore taken to review the experience and identify areas where the current guidance could be more permissive without compromising its basic principles, and where additional explanation could be provided regarding the possibility of reducing the amount of data needed for regulatory approval. The meeting participants applauded the leading role taken by the WHO in providing a much-needed streamlined approach for development and evaluation of SBPs which will provide efficient and cost-effective product development and increase patient access to treatments. It was recognized that the principles as currently described in the draft WHO guidelines are based on sound science and experience gained over the last fifteen years of biosimilar approvals. However, since these guidelines when finalised will constitute the global standard for biosimilar evaluation and assist national regulatory authorities in establishing revised guidance and regulatory practice in this complex area, it was felt that further revision and clarity on certain perspectives in specific areas was necessary to dispel uncertainties arising in the current revised version. This report describes the principles in the draft guidelines, including topics discussed and consensus reached.

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WHO guidelines serve as a basis for the development of national regulatory framework for biosimilars.

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Revision of guidelines is to provide more flexibility and clarification on data required for regulatory approval.

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Revised guidelines would contribute to improving consistency on regulatory decision and patient access to treatments.

A study on accumulator analysis for the valve performance evaluation system of nuclear power plants

To evaluate the valves used in the nuclear power plants are working properly under the required conditions, the performance and capacity test should be performed. In the test system, the accumulator was employed to control the large amount of high pressure and high temperature steam generated in the boiler precisely. In the accumulating process, the steam is often condensed. In order to prevent condensation, it is needed to install heaters and preheat the accumulator. However, if the size of the accumulator becomes large, the installation of the heater may not be easy. Therefore, when the test is conducted, the system was preheated by the latent heat generated from the phase change. Insufficient thermal insulation may cause temperature differences and it can cause mechanical problems in the accumulator structure. If insulation is sufficient, the temperature difference is indicated by the height. As the cooled condensate moves downwards, the condensate is discharged by the drain valve control and the temperature difference of the structure can be disappeared. The results of this paper can be applied to the conceptualization of equipment that uses latent heat and for the design of high-precision steam experimental devices or the design of high-capacity steam utilization systems.

Learning Gains from a Recurring "Teach and Question" Homework Assignment in a General Biology Course: Using Reciprocal Peer Tutoring Outside Class

Providing students with one-on-one interaction with instructors is a big challenge in large courses. One solution is to have students interact with their peers during class. Reciprocal peer tutoring (RPT) is a more involved interaction that requires peers to alternate the roles of "teacher" and "student." Theoretically, advantages for peer tutoring include the verbalization and questioning of information and the scaffolded exploration of material through social and cognitive interaction. Studies on RPT vary in their execution, but most require elaborate planning and take up valuable class time. We tested the effectiveness of a "teach and question" (TQ) assignment that required student pairs to engage in RPT regularly outside class. A quasi-experimental design was implemented: one section of a general biology course completed TQ assignments, while another section completed a substitute assignment requiring individuals to review course material. The TQ section outperformed the other section by ∼6% on exams. Session recordings were coded to investigate correlation between TQ quality and student performance. Asking more questions was the characteristic that best predicted exam performance, and this was more predictive than most aspects of the course. We propose the TQ as an easy assignment to implement with large performance gains.

Differential CMOS Sub-Terahertz Detector with Subthreshold Amplifier

We propose a differential-type complementary metal-oxide-semiconductor (CMOS) sub-terahertz (THz) detector with a subthreshold preamplifier. The proposed detector improves the voltage responsivity and effective signal-to-noise ratio (SNR) using the subthreshold preamplifier, which is located between the differential detector device and main amplifier. The overall noise of the detector for the THz imaging system is reduced by the preamplifier because it diminishes the noise contribution of the main amplifier. The subthreshold preamplifier is self-biased by the output DC voltage of the detector core and has a dummy structure that cancels the DC offsets generated by the preamplifier itself. The 200 GHz detector fabricated using 0.25 μm CMOS technology includes a low drop-out regulator, current reference blocks, and an integrated antenna. A voltage responsivity of 2020 kV/W and noise equivalent power of 76 pW/√Hz are achieved using the detector at a gate bias of 0.5 V, respectively. The effective SNR at a 103 Hz chopping frequency is 70.9 dB with a 0.7 W/m² input signal power density. The dynamic range of the raster-scanned THz image is 44.59 dB.

Osteoporosis medication prescribing in British Columbia and Ontario: impact of public drug coverage

We compared the patterns of osteoporosis medication prescribing between two provinces in Canada with different public drug coverage policies. Oral bisphosphonates were the primary drugs used, yet access to the second-generation oral bisphosphonates (alendronate, risedronate) was limited in one region. Implications of differential access to oral bisphosphonates warrants further study.

INTRODUCTION

Approved therapies for treating osteoporosis in Canada include bisphosphonates, calcitonin, denosumab, raloxifene, and teriparatide. However, significant variation in access to these medications through public drug coverage exists across Canada. We sought to compare patterns of osteoporosis medication prescribing between British Columbia (BC) and Ontario.

METHODS

Using dispensing data from BC (PharmaNet) and Ontario (Ontario Drug Benefits), we identified all new users of osteoporosis medications aged 66 or more years from 1995/1996 to 2008/2009. We summarized the number of new users by fiscal year, sex, and index drug for each province. BC data were also stratified by whether drugs were dispensed within or outside public PharmaCare.

RESULTS

We identified 578,254 (n = 122,653 BC) eligible new users. Overall patterns were similar between provinces: (1) most patients received an oral bisphosphonate (93% in BC and 99% in Ontario); (2) etidronate prescribing declined after 2001/2002, reaching a low of 41% in BC and 10% in Ontario in 2008/2009; and (3) the proportion of males treated increased over time, from 7% in 1996/1997 to 25% in 2008/2009. However, we note major differences within versus outside the BC PharmaCare system. In particular, <2% of drugs dispensed within PharmaCare compared to 79% of drugs dispensed outside PharmaCare were for a second-generation bisphosphonate (alendronate or risedronate).

CONCLUSIONS

Oral bisphosphonates are the primary drugs used to treat osteoporosis in Canada. Prescribing practices changed over time as newer medications came to market, yet access to second-generation bisphosphonates through BC PharmaCare was limited. Implications of differential access to oral bisphosphonates warrants further study.

Cocaine or selective block of dopamine transporters influences multisecond oscillations in firing rate in the globus pallidus

Previous studies have shown that direct-acting dopamine agonists modulate the multisecond oscillations which are present in globus pallidus spike trains in vivo in awake rats. To investigate possible modulation by endogenous dopamine and by other monoamines, and by drugs with abuse potential, cocaine or selective monoamine uptake blockers were injected systemically during extracellular recording of single globus pallidus neurons and the results analyzed with spectral and wavelet methods. Both cocaine and the selective dopamine uptake blocker GBR-12909 significantly shortened the period of multisecond oscillations, as well as increasing overall firing rate. Cocaine effects were blocked by dopamine antagonist pretreatment, as well as by N-methyl-D-aspartate receptor antagonist (MK-801) pretreatment. Desipramine and fluoxetine (blockers of norepinephrine and serotonin uptake, respectively) had no significant effects on multisecond oscillations. The results suggest that dopamine has a primary role among monoamines in modulating multisecond oscillations in globus pallidus activity, and that tonic dopaminergic and glutamatergic transmission is necessary for normal slow oscillatory function.

Outdoor air pollutants derived from industrial processes may be causally related to the development of asthma in children

BACKGROUND

There is no consistent evidence that outdoor air pollutants are involved in the development of asthma.

OBJECTIVE

The aim of this study was to determine whether outdoor air pollutants derived from industrial processes were related to the prevalence of asthma, bronchial hyperresponsiveness, and atopy in exposed children.

METHODS

A total of 7,511 children from 7 to 12 years of age were recruited in the study. Eight hundred eighty-eight of 1,009 (88%) of the subjects living around industrial factories and 5,998 of 6,502 (92%) living in a less polluted neighboring area responded to the ISAAC questionnaire. A total of 1,492 subjects 8 to 9 years old underwent skin prick tests for 11 common aeroallergens. A total of 732 of the subjects from 8 to 9 years of age underwent bronchial provocation tests with hypertonic saline (BPT-HS).

RESULTS

The prevalence of ever experiencing wheezing and wheeze during the last 12 months was 25.6%, and 18.8% among the children living in the more polluted area. This was significantly higher than for those living in the less polluted area (14.2% and 9.0%, respectively). The positive rate of BPT-HS (the provocative dose of hypertonic saline causing 20% fall of FEV, < or = 23 mL) was higher among those in the more polluted area than in children living in the less polluted area (12.2% vs 7.5%). However, the rate of atopy based on the skin tests was the same in the two groups (28.3% vs 30.6%).

CONCLUSIONS

The prevalence of asthma and bronchial hyperresponsiveness was higher among children living around the heavily industrial area compared with those living in the less polluted area, despite similar atopic sensitization.

Drugs used in the treatment of attention-deficit/hyperactivity disorder affect postsynaptic firing rate and oscillation without preferential dopamine autoreceptor action

BACKGROUND

Current theories propose that low doses of catecholaminergic stimulants reduce symptoms in patients with attention-deficit/hyperactivity disorder by acting on autoreceptors to reduce catecholaminergic transmission; few data are available that directly address this hypothesis.

METHODS

We investigated the autoreceptor and postsynaptic receptor actions of systemically administered stimulants on dopaminergic systems in rats with single-unit recording in the substantia nigra pars compacta and globus pallidus, respectively.

RESULTS

Dose-response curves for rate indicated that the potencies of the indirect-acting agonists methylphenidate and D-amphetamine at dopaminergic autoreceptors were not greater than at postsynaptic receptors; in fact, D-amphetamine was more potent postsynaptically. In addition to effects on firing rate, spectral/wavelet analyses indicated that these drugs had prominent effects on postsynaptic multisecond oscillations. These oscillations were shifted by stimulants from baseline periods of approximately 30 sec to periods of 5-10 sec. Effects on pattern were found at doses as low as 1.0 mg/kg (methylphenidate) and 0.2 mg/kg (D-amphetamine). At this latter dose, D-amphetamine had little effect presynaptically.

CONCLUSIONS

These and prior results demonstrate that there is no autoreceptor-preferring dose range of catecholaminergic stimulants; these drugs at low doses are unlikely to reduce motor activity by this mechanism. Nonetheless, they might affect attentive and cognitive processes by modulating multisecond temporal patterns of central activity.