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This paper presents a shunt protection technique to improve the hot-switching reliability of metal-contact radio-frequency microelectromechanical systems (RF-MEMS) switches. The proposed technique places shunt protection contacts in front of the main contact of an RF-MEMS metal contact switch to block RF signal while the main contact is switching ON or OFF. The shunt protection contact creates a local cold-switching condition for the main contact to increase the lifetime of the switch under hot-switching condition. The shunt protection technique can also increase the overall isolation of the switch. To demonstrate the technique, RF-MEMS switches with and without shunt protection were fabricated using all metal process. Compared with the unprotected switch, the protected switch has longer lifetime under hot-switching condition. The protected switch has >100-million cycles and up to 500-million cycles lifetime under the 1-W hot-switching condition, measured in open-air laboratory environment. Besides, the isolation of the shunt-protected switch is 70 dB at 1.0 GHz and 36 dB at 40 GHz, and the insertion loss is 0.30 dB at 1.0 GHz and 0.43 dB at 40 GHz.

This paper presents a tunable active bandpass filter with bandwidth-adjustable notches close to the passband for wideband blocker suppression with high attenuation. The proposed filter is composed of a 3-pole N-path bandstop filter in cascade with an N-path bandpass filter, where the center frequency of the bandpass filter is offset from the bandstop filters. With proper tuning of the coupling capacitors in the bandstop filter, three adjacent notches can be created which provides a larger suppression bandwidth. An implementation of the filter in 65-nm CMOS exhibits a passband tunable between 0.1-1.1 GHz, with a 3-dB bandwidth of 12.4-14.2 MHz, a gain of 9.5-10.3 dB, a noise figure of 4.3-5.8 dB, and a total power consumption of 40-64.3 mW. The blocker 1-dB compression point is 6.5 dBm and the out-of-band IIP3 is 18.4 dBm. The reported filter provides a promising solution to multi-standard, multi-frequency software-defined radio applications.

This paper presents a dielectric waveguide based multi-mode sub-THz interconnect channel for high data-rate high bandwidth-density planar chip-to-chip communications. By using a proposed new transition of microstrip line to dielectric waveguide, the interconnect channel achieves wide bandwidth on two orthogonal modes Ey11 and Ex11. To the authors' knowledge, this is the first demonstration of a multi-mode sub-THz interconnect channel. The measured minimum insertion losses for mode Ey11 and mode Ex11 are 8.0 dB with 21.3 GHz 3-dB bandwidth and 9.0 dB with 24.0 GHz 3-dB bandwidth, respectively.

This paper presents a high energy-efficiency and high bandwidth-density dielectric waveguide based sub-THz interconnect. A bumpless flip-channel packaged nearfield coupled transition based channel together with the holistic active circuit design scheme boosts the energy efficiency to the record based on the authors' best knowledge. The channel demonstrates the transmission loss of 0.04 dB/mm and the bending loss of 0.17 dB/bend. This proof-of-concept sub-THz link, with active circuits in 65 nm bulk CMOS, demonstrates the bit error rate of less than 1 × 10-12 up to 12.1 Gb/s with a high bandwidth density of 80.7 Gb/s/mm2. The record energy efficiency of 0.32 pJ/b is achieved at 10 Gb/s with 3.2 mW power consumption. The communication distance is 46.2 mm.

This paper presents a compact 213 GHz fundamental oscillator with an optimal embedding network that maximizes the output power. Fabricated in 65-nm bulk CMOS, the oscillator occupies a core area of only 70×40 pm2, owing to the use of a compact low-loss capacitive transformer structure. The oscillator achieves 0.56-mW output power while consuming a DC current of 14.35 mA from a 1-V power supply, representing a recording-breaking DC-to-RF efficiency of 3.9% amongst fundamental oscillators above 200 GHz.

A new wake-up receiver (WuRx) designed in 0.13 μm CMOS process is hybrid-integrated with a micro-electromechanical system (MEMS) RF resonator. While only consuming 166 nW of power (18.8 nW for the comparator and 147 nW for periphery), the WuRx is capable of detecting RF signals as weak as -60 dBm. In order to achieve this sensitivity, a passive voltage-boosting network comprised of a high quality factor (high-Q) piezoelectric MEMS resonator is utilized, in place of an inductor, to amplify the received voltages applied to a CMOS rectifier. The output of the rectifier is then applied to a low-power comparator used to set a logical bit that indicates when an RF signal has been detected. The trade-offs in designing the voltage boosting network are explained and an equation for the optimum number of rectifier stages is derived.

This paper presents a tunable active bandpass filter with adjustable notch close to the passband for blocker rejection. The proposed filter is based on two-path signal cancellation and consists of a top-C coupled tunable bandpass filter in parallel with an inductor. The proposed filter is implemented with high-Q N-path filter/resonator blocks in 65-nm CMOS process. The passband of the filter is tunable from 0.4 GHz to 2.2 GHz with a 3-dB bandwidth of 14.4-15.6 MHz, an insertion loss of 3.6-5.8 dB, a noise figure of 3.8-6 dB, and a total power consumption of 12.4-42 mW. Transmission zero is created close to the passband with a minimal offset of 40 MHz and are tunable across a 25 MHz range with up to 54 dB rejection. The blocker 1-dB compression point is 8.5 dBm and the out-of-band IIP3 is 23.5 dBm. The proposed filter provides a promising solution to multi-standard, multi-frequency software-defined radio applications.

This paper presents the design and characterization of a miniaturized tunable bandpass filter utilizing high-Q ceramic coaxial resonators and commercially available RF-MEMS tunable digital capacitors. A proof-of-concept 2-pole tunable filter occupying only 10 × 10 mm2 is demonstrated with a frequency tuning range of 800-1100 MHz and bandwidth tuning range of 6-13%.

Wake-up receivers have been proposed to provide continuous sensing in a wide variety of Internet of Things applications. To achieve impedance transformation and passive amplification between the antenna and rectifier node, current wake-up receivers employ large magnetic transformers that exhibit both low Q and inductance per unit area in planar CMOS technology. The adoption of piezoelectric MEMS resonators to replace magnetic transformers offers an area-efficient, high-Q, monolithic solution that allows large voltage amplification for ultra-low-power applications. AlN Contour Mode Resonators (CMRs) are an emerging class of piezoelectric MEMS that offers frequency reconfiguration via lithography.

A monolithic piezoelectric MEMS-CMOS resonant transformer that can be used in ultra-low-power high-efficiency RF sensing applications is presented for the first time. The MEMS-CMOS resonant transformer is based on a 59 MHz 2-port Aluminum Nitride (AlN) Contour Mode Resonator (CMR) bonded to a 0.18 μm NMOS-based rectifier for voltage boosting and RF-to-DC conversion. The integrated device is fabricated in a foundry-based process by conductive eutectic wafer bonding. To amplify the voltage, the AlN CMR is designed to attain a large quality factor (Q=1150) and a relatively low dielectric capacitance (C0=1.51 pF) in relation to the number of rectifier stages (n=20). As a result, a ten-fold voltage gain MEMS-CMOS resonant transformer is demonstrated in this work.

Background: Visitation has a positive effect on patients and families, yet, it can disrupt intensive care unit (ICU) care and increase the risk of patient infections, which previously favoured face‐to‐face visits. The coronavirus disease 2019 (COVID‐19) pandemic has raised the importance of virtual visits and led to their widespread adoption globally, there are still many implementation barriers that need to be improved. Therefore, this review aimed to explore the use of ICU virtual visit technology during the COVID‐19 pandemic and the barriers and facilitators of virtual visits to improve virtual visits in ICUs. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines, six databases (CINAHL, China National Knowledge Infrastructure [CNKI], PubMed, Cochrane, VIP and Wang Fang databases) were searched for empirical studies published between 1 January 2020 and 22 October 2023. Studies that investigated and reported barriers to and facilitators of implementing virtual visits in ICUs during the COVID‐19 pandemic were included. Evidence from the included studies was identified and thematically analysed using Thomas and Harden's three‐step approach. Study quality was appraised with the Mixed‐Methods Appraisal Tool. Results: A total of 6770 references were screened, of which 35 studies met the inclusion criteria after a full‐text review. Eight main barriers to virtual visits use were identified: technical difficulties; insufficient resources; lack of physical presence and nonverbal information; low technical literacy; differences in families' perceptions of visual cues; privacy and ethics issues; inequitable access and use of virtual visit technology; and lack of advance preparation. Four facilitating factors of virtual visit use were identified: providing multidimensional professional support; strengthening coordination services; understanding the preferences of patients and their families; and enhancing privacy and security protection. In the quality appraisal of 35 studies, 12 studies were rated as low, five as medium and 18 as high methodological quality. Conclusion: This review identified key facilitating factors and barriers to ICU virtual visits, which can foster the development of infrastructure, virtual visiting workflows, guidelines, policies and visiting systems to improve ICU virtual visiting services. Further studies are necessary to identify potential solutions to the identified barriers. [ABSTRACT FROM AUTHOR]

This paper presents a tunable active bandpass filter (BPF) with adjustable transmission zeros (TZs) close to the passband for software-defined radio (SDR) applications. The RF front-end frequency selectivity is enhanced by the creation of TZs that also improve the out-of-band (OOB) input-referred third-order intercept point (IIP3). The filter is based on two-path signal cancellation and consists of a tunable BPF in parallel with two tunable bandstop filters. This combination ensures the correct amplitude and phase relationships across a wide tuning range to create adjustable TZs without sacrificing the gain of the passband. This paper presents in detail the design considerations and guidelines, as well as analysis of the filter performance in the presence of nonidealities such as parasitics and imperfect clock signal shape. The proposed filter is implemented with high-Q N-path filter blocks in a 65-nm CMOS process. The passband of the filter is tunable from 0.1 to 1.4 GHz with a 3-dB bandwidth of 9.8-10.2 MHz, a gain of 21.5-24 dB, a noise figure of 3-4.2 dB, and a total power consumption of 50-73 mW. TZs are created on both sides of the passband with a minimal offset of 25 MHz and are tunable across a 20-MHz range with up to a 60-dB rejection. The measured blocker 1-dB compression point is 8 dBm and the OOB IIP3 is 23 dBm. The reported filter provides a promising on-chip filtering solution for multistandard multifrequency SDR applications with improved interference mitigation capabilities.

Ferroptosis, a form of regulated cell death that is induced by excessive lipid peroxidation, is a key tumour suppression mechanism.sup.1-4. Glutathione peroxidase 4 (GPX4).sup.5,6 and ferroptosis suppressor protein 1 (FSP1).sup.7,8 constitute two major ferroptosis defence systems. Here we show that treatment of cancer cells with GPX4 inhibitors results in acute depletion of N-carbamoyl-l-aspartate, a pyrimidine biosynthesis intermediate, with concomitant accumulation of uridine. Supplementation with dihydroorotate or orotate--the substrate and product of dihydroorotate dehydrogenase (DHODH)--attenuates or potentiates ferroptosis induced by inhibition of GPX4, respectively, and these effects are particularly pronounced in cancer cells with low expression of GPX4 (GPX4.sup.low). Inactivation of DHODH induces extensive mitochondrial lipid peroxidation and ferroptosis in GPX4.sup.low cancer cells, and synergizes with ferroptosis inducers to induce these effects in GPX4.sup.high cancer cells. Mechanistically, DHODH operates in parallel to mitochondrial GPX4 (but independently of cytosolic GPX4 or FSP1) to inhibit ferroptosis in the mitochondrial inner membrane by reducing ubiquinone to ubiquinol (a radical-trapping antioxidant with anti-ferroptosis activity). The DHODH inhibitor brequinar selectively suppresses GPX4.sup.low tumour growth by inducing ferroptosis, whereas combined treatment with brequinar and sulfasalazine, an FDA-approved drug with ferroptosis-inducing activity, synergistically induces ferroptosis and suppresses GPX4.sup.high tumour growth. Our results identify a DHODH-mediated ferroptosis defence mechanism in mitochondria and suggest a therapeutic strategy of targeting ferroptosis in cancer treatment. DHO dehydrogenase regulates ferroptosis by preventing mitochondrial lipid peroxidation and its inhibition suppresses growth in tumours with low levels of GPX4., Author(s): Chao Mao [sup.1] , Xiaoguang Liu [sup.1] , Yilei Zhang [sup.1] , Guang Lei [sup.1] , Yuelong Yan [sup.1] , Hyemin Lee [sup.1] , Pranavi Koppula [sup.1] [sup.2] , [...]

Obesity is a systemic and chronic inflammation, which seriously endangers people's health. People tend to diet to control weight, and the short-term effect of dieting in losing weight is significant, but the prognosis is limited. With weight loss and recovery occurring frequently, people focus on weight cycling. The effect of weight cycling on a certain tissue of the body also has different conclusions. Therefore, this article systematically reviews the effects of body weight cycling on the body and finds that multiple weight cycling (1) increased fat deposition in central areas, lean mass decreased in weight loss period, and fat mass increased in weight recovery period, which harms body composition and skeletal muscle mass; (2) enhanced the inflammatory response of adipose tissue, macrophages infiltrated into adipose tissue, and increased the production of pro-inflammatory mediators in adipocytes; (3) blood glucose concentration mutation and hyperinsulinemia caused the increase or decrease in pancreatic β-cell population, which makes β-cell fatigue and leads to β-cell failure; (4) resulted in additional burden on the cardiovascular system because of cardiovascular rick escalation. Physical activity combined with calorie restriction can effectively reduce metabolic disease and chronic inflammation, alleviating the adverse effects of weight cycling on the body. [ABSTRACT FROM AUTHOR]