Search

Terahertz (THz) waves have exhibited promising prospects in 6G/7G communications, sensing, nondestructive detection, material modulation, and biomedical applications. With the development of high-power THz sources, more and more nonlinear optical effects at THz frequency and THz-induced nonlinear optical phenomena are investigated. These studies not only show a clear physics picture of electrons, ions, and molecules but also provide many novel applications in sensing, imaging, communications, and aerospace. Here, we review recent developments in THz nonlinear physics and THz-induced nonlinear optical phenomena. This review provides an overview and illustrates examples of how to achieve strong THz nonlinear phenomena and how to use THz waves to achieve nonlinear material modulation.

Objective: To explore the effects of ultrasound-guided serratus anterior plane block (SAPB) and thoracic paravertebral block (TPVB) on opiate dosage and stress response in patients undergoing thoracoscopic radical resection of lung cancer. Methods: A total of 130 patients undergoing elective thoracoscopic radical resection of lung cancer in Changshu Second Peoples Hospital between June 2019 and January 2022 were enrolled. According to the random number table method, they were divided into SAPB group (65 cases, ultrasound-guided SAPB before anesthesia induction) and TPVB group (65 cases, ultrasound-guided TPVB before anesthesia induction). After surgery, all underwent patient-controlled intravenous analgesia with analgesia pumps. The timepoints including preoperative, thoracic closure, and postoperative 2, 6, and 24 hours were set as T1, T2, T3, T4 and T5, respectively, and the intraoperative blood loss and fluid supplement, operation time, intraoperative dosages of sufentanil and propofol, and postoperative cumulative dosages of sufentanil at T3, T4 and T5 in the two groups were recorded. At T3, T4 and T5, pain changes were evaluated by Prince-Henry scores. The levels of prostaglandins E2 (PGE2), norepinephrine (NE) and cortisol (Cor) were detected by enzyme-linked immunosorbent assay. The partial pressure of arterial oxygen was detected by a blood gas analyzer, and oxygenation index (OI) was calculated. The occurrence of postoperative adverse events (PAEs) in the two groups was recorded. Results: From T3 to T5, levels of PGE2, NE, and Cor in SAPB group were significantly lower than those in TPVB group (P＜0.05). OI at T2 to T4 was significantly lower than that at T1, while OI at T5 was significantly higher than that at T2, T3, and T4 in both groups (P＜0.05). From T2 to T4, OI in SAPB group was significantly higher than that in TPVB group (P＜0.05). Compared with TPVB group, the cumulative consumption of sufentanil in SAPB group slightly decreased from T3 to T5, but the differences were not statistically significant (P>0.05). The incidences of nausea and vomiting (6.15% vs 18.46%, χ2=4.561, P=0.033), atelectasis(3.08% vs 12.31%, χ2=3.900, P=0.048) and hypotension (7.69% vs 20.00%, χ2=4.127, P=0.042) in SAPB group were lower than those in TPVB group. Conclusion: Compared with TPVB, ultrasound-guided SAPB can relieve stress response, promote the recovery of pulmonary oxygenation and reduce PAEs in patients undergoing thoracoscopic radical resection of lung cancer, but whether it can significantly reduce the dosage of opiates needs to be further explored.

Modern stealth application systems require integrated meta-devices to operate effectively and have gained significant attention recently. This research paper proposes a 1-bit coding metasurface (CM) design. The fundamental component of the proposed CM is integrated to convert linearly polarized incoming electromagnetic waves into their orthogonal counterpart within frequency bands of 12.37–13.03 GHz and 18.96–32.37 GHz, achieving a polarization conversion ratio exceeding 99%. Furthermore, it enables linear-to-circular polarization conversion from 11.80 to 12.29, 13.17 to 18.44, and 33.33 to 40.35 GHz. A second element is produced by rotating a fundamental component by 90°, introducing a phase difference of π (pi) between them. Both elements are arranged in an array using a random aperiodic coding sequence to create a 1-bit CM for reducing the radar cross-section (RCS). The planar structure achieved over 10 dB RCS reduction for polarized waves in the frequency bands of 13.1–13.8 GHz and 20.4–30.9 GHz. A prototype was fabricated and tested, with the experimental results showing a good agreement with the simulated outcomes. The proposed design holds potential applications in radar systems, reflector antennas, stealth technologies, and satellite communication. [ABSTRACT FROM AUTHOR]

Background & Aims: Gut–vascular barrier (GVB) dysfunction has been shown to be a prerequisite for nonalcoholic fatty liver disease (NAFLD) development. However, the causes of GVB disruption and the underlying mechanisms are still elusive. Here, we explored whether and how Escherichia coli (E. coli) NF73‐1, a pathogenic E. coli strain isolated from nonalcoholic steatohepatitis patients, contributes to NAFLD by modulating the GVB. Methods: C57BL/6J mice were fed with high‐fat diet (HFD) or normal diet in the presence or absence of E. coli NF73‐1 for the indicated time periods. Intestinal barrier function and infiltration of immune cells were evaluated in these mice. Endothelial cells were exposed to E. coli NF73‐1 for barrier integrity analysis. Results: HFD‐induced GVB disruption preceded the damage of intestinal epithelial barrier (IEB) as well as intestinal and hepatic inflammatory changes and can be reversed by vascular endothelial growth factor A blockade. Antibiotic treatment prevented mice from HFD‐induced liver steatosis by restoration of the GVB. Notably, E. coli NF73‐1 caused a more conspicuous damage of GVB than that of the IEB and contributed to NAFLD development. Mechanistically, E. coli NF73‐1 dismantled the GVB by inhibiting the Wnt/β‐catenin signalling pathway. Activation of Wnt/β‐catenin improved the GVB and impeded the translocation of E. coli NF73‐1 into the liver in vitro and in vivo. Conclusions: E. coli NF73‐1 disrupts GVB and aggravates NAFLD via inhibiting the Wnt/β‐catenin signalling pathway. Targeting E. coli NF73‐1 or selectively enhancing the GVB may act as potential avenues for the prevention and treatment of NAFLD. [ABSTRACT FROM AUTHOR]

A large‐scale outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2) occurred in Shanghai, China, in early December 2022. To study the incidence and characteristics of otitis media with effusion (OME) complicating SARS‐CoV‐2, we collected 267 middle ear effusion (MEE) samples and 172 nasopharyngeal (NP) swabs from patients. The SARS‐CoV‐2 virus was detected by RT‐PCR targeting. The SARS‐CoV‐2 virus, angiotensin‐converting enzyme 2 (ACE2), and transmembrane serine protease 2 (TMPRSS2) expression in human samples was examined via immunofluorescence. During the COVID‐19 epidemic in 2022, the incidence of OME (3%) significantly increased compared to the same period from 2020 to 2022. Ear symptoms in patients with SARS‐CoV‐2 complicated by OME generally appeared late, even after a negative NP swab, an average of 9.33 ± 6.272 days after COVID‐19 infection. The SARS‐CoV‐2 virus was detected in MEE, which had a higher viral load than NP swabs. The insertion rate of tympanostomy tubes was not significantly higher than in OME patients in 2019–2022. Virus migration led to high viral loads in MEE despite negative NP swabs, indicating that OME lagged behind respiratory infections but had a favorable prognosis. Furthermore, middle ear tissue from adult humans coexpressed the ACE2 receptor for the SARS‐CoV‐2 virus and the TMPRSS2 cofactors required for virus entry. [ABSTRACT FROM AUTHOR]

This paper presents the design and measurement of an IEEE 802.11ad standard compatible RF transceiver for 60 GHz wireless communication systems. In addition to the traditional half-duplex (HD) mode, this work supports full-duplex (FD) operations to deliver better channel utilization and faster response times for the system. The isolation between the transmitter and receiver from the architecture design to system integration for FD operations has been fully considered. A digital self-interference cancellation (DSIC) is implemented in MATLAB to verify the FD performance. The super-heterodyne architecture with an intermediate frequency (IF) of 12 GHz is designed to suppress the image frequencies without using extra filters. A flexible phase-locked loop (PLL) synthesizer provides a local oscillator (LO) frequency with a 2 kHz resolution. Other than the time division duplex (TDD) mode used in the conventional 60 GHz system, a wide-bandwidth baseband digital variable-gain amplifier (DVGA) with a 3 dB bandwidth of more than 4 GHz also supports frequency division duplex (FDD) operations. The transceiver chip is fabricated using the Tower Jazz 0.18 µm SiGe BiCMOS process. With an on-board antenna, the transceiver covers all four channels in the 802.11ad standard, with MCS-12 (7.04 Gbps under 1.76 GSym/s and 16-QAM) under 1.5 m. In the proposed system design, the RF frontend-based self-interference (SI) suppression from the local transmitter to receiver LNA is around 54 dB. To achieve a practical FD application, the SI is further suppressed with the help of a digital SI compensation. The measured power consumption for the transmitter and receiver configurations are 194 mW and 231 mW, respectively, in HD mode and 398 mW for the FDD or FD operation mode. [ABSTRACT FROM AUTHOR]