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Abstract Parity-time (PT) symmetry is an active research area that provides a variety of new opportunities for different systems with novel functionalities. For instance, PT symmetry has been used in lasers and optoelectronic oscillators to achieve single-frequency lasing or oscillation. A single-frequency system is essentially a static PT-symmetric system, whose frequency is time-invariant. Here we investigate time-variant PT symmetry in frequency-scanning systems. Time-variant PT symmetry equations and eigenfrequencies for frequency-scanning systems are developed. We show that time-variant PT symmetry can dynamically narrow the instantaneous linewidth of frequency-scanning systems. The instantaneous linewidth of a produced frequency-modulated continuous-wave (FMCW) waveform is narrowed by a factor of 14 in the experiment. De-chirping and radar imaging results also show that the time-variant PT-symmetric system outperforms a conventional frequency-scanning one. Our study paves the way for a new class of time-variant PT-symmetric systems and shows great promise for applications including FMCW radar and lidar systems.

In the context of the San Gavain hydroelectric power station diversion tunnel project in Peru, this paper studies the surrounding rock instability mechanism using a combination of numerical simulation methods and model test and presents the enclosing rock instability criterion based on the catastrophe model. The study demonstrates that the distribution of stress and displacement during tunnel excavation is more affected by the presence of laminated joints; the thinner the layer thickness, the more prominent the influence of laminations, and the higher the deformation of the surrounding rock. With the increase in layer thickness, the resultant displacement shows the law of gradual decrease; when the layer thickness is greater than 16 cm, the rate of decrease gradually slows down, and the maximum displacement is 0.201 mm. The failure mode of the layered perimeter rock tunnel with a 45° inclination angle primarily shows up as tensile deformation at the left arch shoulder and shear slip deformation at the right arch foot under the combined action of blasting disturbance load and excavation. Based on the instability analysis of the fold catastrophe model and cups catastrophe model, the influence of bending deformation between layers of surrounding rock is generally greater than shear slip deformation. The instability criterion Δ＜0 exists in all working conditions, bending instability damage may occur in all cases. When the layer thickness is greater than 24 cm, the shear slip instability criterion is greater than zero for 0–2 ms, and the system is always in a stable state, and when the layer thickness is less than 24 cm, the system may be destabilized at 1.5 ms.

Abstract To facilitate intelligent interconnection among people, machines, and things, the next generation of communication technology must incorporate various sensing functions besides high-speed wireless communications. Integration of radar, wireless communications, and spectrum sensing is being investigated for 6G with increased spectral efficiency, enhanced system integration, and reduced cost. Microwave photonics, a technique that combines microwave engineering and photonic technology is considered an effective solution for implementing the integration and breaking the bottleneck problems of electronic solutions. Here, we show a photonics-assisted joint radar, wireless communications, and spectrum sensing system that enables precise perception of the surrounding physical and electromagnetic environments while maintaining high-speed communication. Communication signals and frequency-sweep signals are merged optically using a shared system architecture and hardware to achieve signal level sharing, ultimately simultaneously achieving high-accuracy radar ranging and imaging with a measurement error within ± 4 cm and an imaging resolution of 25 × 24.7 mm, high-data-rate wireless communications at 2 Gbaud, and wideband spectrum sensing with a frequency measurement error within ±10 MHz in a 6 GHz bandwidth.

Abstract Background With the prevalence of coronavirus disease 2019 (COVID-19), many severe cases have been discovered worldwide. Here, a case of concurrent pneumomediastinum, pneumoretroperitoneum, and intestinal perforation was reported. This case was the first report on COVID-19-induced related complications. Case presentation A 74-year-old female patient was hospitalized for COVID-19. Air leakage was unexpectedly found during imaging reexamination. Considering the unobvious subjective feeling of the patient, a conservative treatment was given at the early stage, and finally, sigmoid colon perforation was surgically confirmed. The family gave up the treatment at last, because the patient could not be taken off the ventilator. Coincidentally, the patient also had abnormal renal anatomical position. This situation led to an abnormal air leakage direction and the atypical manifestations of peritonitis. It was also one of the important reasons for the delayed diagnosis and treatment of the disease. Conclusions Clinicians should be vigilant for spontaneous gastrointestinal perforation in patients with COVID-19, particularly those undergoing treatment with glucocorticoids and tocilizumab. The case is shared to highlight this rare and fatal extrapulmonary manifestation of COVID-19 and further assist clinicians to raise their awareness and timely implement imaging investigation and multidisciplinary intervention so as to facilitate early discovery, diagnosis and treatment and reduce the mortality.

Schizophrenia (SCZ) is a severe neuropsychiatric disorder characterized by cognitive, affective, and social dysfunction, resulting in hallucinations, delusions, emotional blunting, and disordered thinking. In recent years, proteomics has been increasingly influential in SCZ research. Glycosylation, a key post-translational modification, can alter neuronal stability and normal signaling in the nervous system by affecting protein folding, stability, and cellular signaling. Recent research evidence suggests that abnormal glycosylation patterns exist in different brain regions in autopsy samples from SCZ patients, and that there are significant differences in various glycosylation modification types and glycosylation modifying enzymes. Therefore, this review explores the mechanisms of aberrant modifications of N-glycosylation, O-glycosylation, glycosyltransferases, and polysialic acid in the brains of SCZ patients, emphasizing their roles in neurotransmitter receptor function, synaptic plasticity, and neural adhesion. Additionally, the effects of antipsychotic drugs on glycosylation processes and the potential for glycosylation-targeted therapies are discussed. By integrating these findings, this review aims to provide a comprehensive perspective to further understand the role of aberrant glycosylation modifications in the pathophysiology of SCZ.

The recent “coal-to-gas'' (CTG) energy policy serves as an important measure to mitigate air pollution in northern China, and also carries out a mission of alleviating rural energy poverty. To unravel the impact of the CTG policy on rural energy poverty, this study examines the effect on economic and well-being dimensions of energy poverty based on data from five villages in northern China. The findings indicate that in general the CTG policy only limitedly alleviated rural energy poverty with effects varying significantly across different social groups. Economically, the policy has significantly increased recipients’ financial burden, and thereby exacerbated their energy poverty. In terms of well-being, the policy has improved the quality of life for villagers by reducing cooking time and raising indoor temperature, thus contributing to a reduction in energy poverty. The CTG recipients are distinguished into four categories based on varied experiences on economic and well-being aspects, with only one third experiencing overall positive impacts. The study suggests that energy policies intended to alleviate energy poverty may paradoxically perpetuate it. The differential impact across social groups calls for more nuanced and targeted approaches to mitigate the adverse effects of energy policies.

An exceptional-point (EP) enhanced fiber-optic bending sensor is reported. The sensor is implemented based on parity-time (PT)-symmetry using two coupled Fabry-Perot (FP) resonators consisting of three cascaded fiber Bragg gratings (FBGs) inscribed in an erbium-ytterbium co-doped fiber (EYDF). The EP is achieved by controlling the pumping power to manipulate the gain and loss of the gain and loss FP resonators. Once a bending force is applied to the gain FP resonator to make the operation of the system away from its EP, frequency splitting occurs, and the frequency spacing is a nonlinear function of the bending curvature, with an increased slope near the EP. Thus, by measuring the frequency spacing, the bending information is measured with increased sensitivity. To achieve high-speed and high-resolution interrogation, the optical spectral response of the sensor is converted to the microwave domain by implementing a dual-passband microwave-photonic filter (MPF), with the spacing between the two passbands equal to that of the frequency splitting. The proposed sensor is evaluated experimentally. A curvature sensing range from 0.28 to 2.74 m−1 is achieved with an accuracy of 7.56×10−4 m−1 and a sensitivity of 1.32 GHz/m−1, which is more than 4 times higher than those reported previously.

This paper demonstrates a five-layer InAs/InP quantum-dash semiconductor optical amplifier (QDash-SOA), which will be integrated into microwave-photonic on-chip devices for millimeter-wave (mmWave) over fibre wireless networking systems. A thorough investigation of the QDash-SOA is conducted regarding its communication performance at different temperatures, bias currents, and input powers. The investigation shows a fibre-to-fibre (FtF) small-signal gain of 18.79 dB and a noise figure of 6.3 dB. In a common application with a 300 mA bias current and 25 °C temperature, the peak FtF gain is located at 1507.8 nm, which is 17.68 dB, with 3 dB gain bandwidth of 56.6 nm. Furthermore, the QDash-SOA is verified in a mmWave radio-over-fibre link with QAM (32 Gb/s 64-QAM 4-GBaud) and OFDM (250 MHz 64-QAM) signals. The average error vector magnitude of the QAM and OFDM signals after a 2 m wireless link could be as low as 8.29% and 6.78%, respectively. These findings highlight the QDash-SOA’s potential as a key amplifying component in future integrated microwave-photonic on-chip devices.

Alpha-fetoprotein (AFP) serves as a crucial diagnostic marker for primary hepatocellular carcinoma (HCC) and germ cell tumors (GCTs), with rare instances of significantly elevated levels in other diseases. In this study, we present a case of an elderly patient who was diagnosed with AFP-producing gastric cancer (AFPGC) following an elevated AFP result during physical examination. In investigating liver cancer at an early stage, the diagnosis was missed because of failure in detecting the lesion, resulting in delayed treatment initiation. AFPGC is a rare aggressive tumor that demands heightened awareness among clinicians to foster early detection, diagnosis, and treatment for improved prognosis.

Background: Depression is a severe mental disorder that poses a significant threat to both the physical and mental wellbeing of individuals. Currently, there are various methods for treating depression, including traditional Chinese herbal formulations like Chaihu-Shugan-San (CSS), which have shown effective antidepressant effects in both clinical and animal research.Objective: This review aims to provide a comprehensive synthesis of evidence related to CSS, considering both preclinical and clinical studies, to uncover its potential multi-level, multi-pathway, and multi-target mechanisms for treating depression and identify its active ingredients.Methods: A thorough search was conducted in electronic databases, including PubMed, MEDLINE, Web of Science, Google Scholar, CNKI, and Wanfang, using keywords such as “Chaihu Shugan” and “depression” to retrieve relevant literature on CSS and its active ingredients. The review process adhered to the PRISMA guidelines.Results: This review consolidates the mechanisms underlying antidepressant effects of CSS and its active ingredients. It emphasizes its involvement in the regulation of monoaminergic neurotransmitter systems, synaptic plasticity, and the hypothalamic-pituitary-adrenal axis, among other aspects.Conclusion: CSS exerts a pivotal role in treating depression through various pathways, including the monoaminergic neurotransmitter system, the hypothalamic-pituitary-adrenal axis, synaptic plasticity, inflammation, brain-derived neurotrophic factor levels, and the brain-gut axis. This review facilitates a comprehensive understanding of the current state of CSS research, fostering an in-depth exploration of the etiological mechanisms of depression and the potential discovery of novel antidepressant drugs.

Abstract Synthetic dimension opens new horizons in quantum physics and topological photonics by enabling new dimensions for field and particle manipulations. The most appealing property of the photonic synthetic dimension is its ability to emulate high-dimensional optical behavior in a unitary physical system. Here we show that the photonic synthetic dimension can transform technical problems in photonic systems between dimensionalities, providing unexpected solutions to technical problems that are otherwise challenging. Specifically, we propose and experimentally demonstrate a fully reconfigurable photonic Galton board (PGB) in the temporal synthetic dimension, in which the temporal high-speed challenge is translated into a spatial fiber-optic length matching problem, leading to the generation of tera-sample-per-second arbitrary waveforms with ultimate flexibility. In the experiments, an arbitrary waveform with a widely tunable sampling rate, ranging from 10.42 GSa/s to a record high of 1.64 TSa/s, is demonstrated. The concept of dimension conversion offers possible solutions to various physical dimension-related problems, such as super-resolution imaging, high-resolution spectroscopy, and high-precision time measurement.

BackgroundDespite the increasing global prevalence of depression, existing treatment methods have limitations. Acupuncture has been recognized for its potential to alleviate various diseases by regulating inflammatory cytokines. However, a comprehensive systematic analysis of the effects of acupuncture on depression through inflammatory cytokines is currently lacking. This review aims to evaluate the impact of acupuncture on inflammatory cytokines in animal models of depression.MethodsA comprehensive search was conducted in PubMed, EMBASE, MEDLINE, and the Research Information Service System to identify studies that met predefined inclusion and exclusion criteria. The quality of each included study was assessed using a 10-item checklist adapted from the Cochrane Collaboration methods and animal data review. Meta-analysis was performed using STATA 17.0 software for literature that met the inclusion criteria.ResultsThe meta-analysis included a total of 21 studies involving 376 rodents. The overall quality of the included reports was rated as moderate or higher. The results demonstrated that acupuncture had a significant effect on the reduction of pro-inflammatory cytokines, including: IL-1β [SMD = 3.36, 95% CI (2.73, 4.00), I2 = 73.3%, p

Abstract Convolutional neural networks are an important category of deep learning, currently facing the limitations of electrical frequency and memory access time in massive data processing. Optical computing has been demonstrated to enable significant improvements in terms of processing speeds and energy efficiency. However, most present optical computing schemes are hardly scalable since the number of optical elements typically increases quadratically with the computational matrix size. Here, a compact on-chip optical convolutional processing unit is fabricated on a low-loss silicon nitride platform to demonstrate its capability for large-scale integration. Three 2 × 2 correlated real-valued kernels are made of two multimode interference cells and four phase shifters to perform parallel convolution operations. Although the convolution kernels are interrelated, ten-class classification of handwritten digits from the MNIST database is experimentally demonstrated. The linear scalability of the proposed design with respect to computational size translates into a solid potential for large-scale integration.

Abstract Background The relationship between headache and thyrotoxicosis has been occasionally mentioned in case reports, but there are few related reports. Thus, the relationship cannot be determined. Few cases of subacute thyroiditis (SAT) presenting as simple headache have been reported. Case presentation This case report describes a middle-aged male patient who came to our hospital with acute headache for 10 days. He was initially misdiagnosed as meningitis due to headache, fever, and increased C-reactive protein. Routine antibacterial and antiviral therapy did not improve his symptoms. Blood test suggested thyrotoxicosis, and color ultrasound suggested SAT sonography. He was diagnosed with SAT. With the treatment of SAT, the headache was relieved after the thyrotoxicosis improved. Conclusion This patient is the first detailed report of SAT presenting with simple headache, which is helpful for clinicians to differentiate and diagnose atypical SAT.

Optical nonreciprocity is of fundamental importance for signal processing in modern optical communication systems but is still facing issues on either high energy consumption, complicated design or on-chip integration. Here, an all-fiber device, containing two mutually coupled Fabry-Perot resonators to realize broken parity-time (PT) symmetry is demonstrated, which may find applications in software-defined optical networks.

Abstract A microwave photonic frequency divider to produce a frequency‐divided microwave signal with its frequency that is one‐third the frequency of the input microwave signal is proposed and experimentally demonstrated. The key novelty of the approach is that the phase control, a condition to realise the frequency division operation, is implemented through controlling the modulator bias voltage, enabling a wideband, high resolution and fast response phase control. One‐third frequency division with an ultra‐high harmonic suppression of over 71.5 dB is demonstrated for the first time.

A chirped microwave waveform with a large time-bandwidth product (TBWP) can find important applications in modern radar systems and microwave imaging systems. Microwave photonics, a field that studies the generation and processing of microwave signals in the optical domain to take advantage of the ultra-wide bandwidth offered by photonics, has been considered an effective solution for high-frequency and large-bandwidth microwave waveform generation. In this paper, an overview on photonic generation of wideband chirped microwave waveforms is provided. Three major methods are discussed including chirped microwave waveform generation based on spectral shaping and frequency-to-time (SS-FTT) mapping, frequency and bandwidth multiplication, and Fourier-domain mode-locking of an optoelectronic oscillator (OEO). The performance of the techniques for chirped microwave waveform generation is studied. Techniques to generate chirped microwave waveforms based on photonic integrated circuits (PICs) are also discussed.

Abstract Introduction: Atrial fibrillation (AF) is the most common sustained arrhythmia. Sorting nexin 10 (SNX10) has been reported to be an important regulator in embryonic development and human diseases, however, little is known about its role in cardiac disease. The aim of this study was to investigate the clinical significance of SNX10 expression in AF. Methods: Nineteen valvular heart disease patients with AF and nine valvular heart disease patients with sinus rhythm (SR) were enrolled. Atrial tissue samples from patients undergoing open heart surgery were examined. Atrial tissues of normal hearts were obtained from two cases’ autopsies. The SNX10 expression and its associations with the degree of fibrosis were analyzed by immunohistochemistry and Masson’s trichrome staining. Results: SNX10 expression was detected in the cytoplasm of cardiac cells in human myocardial tissue. The SNX10 expression level was higher in the SR group than in the AF group (P=0.023). SNX10 expression was negatively associated with the degree of fibrosis (P=0.017, Spearman rho=-0.447), the New York Heart Association degree (P=0.003, Spearman rho=-0.545), left atrial diameter (P=0.038, Spearman rho=-0.393), right atrial diameter (P=0.043, Spearman rho=-0.386), and the brain natriuretic peptide (BNP) level 24 hours after surgery (P=0.030, Spearman rho=-0.426), but not the BNP level before surgery and 72 hours after surgery. No statistical significance was observed between SNX10 and the level of troponin T and C-reactive protein. Conclusion: Decreased SNX10 might serve as a potential risk factor in AF of the valvular heart disease.

Linearly chirped microwave waveforms with high time-bandwidth products would have important applications but are difficult to achieve. Here the authors generate such a waveform in a photonic setting by implementing a micro-disk resonator as a tunable optical bandpass filter in a Fourier-domain mode-locked laser.

Most conventional PT-symmetric systems contain two physically separated modes. Here the authors proposed a PT-symmetric microwave optoelectronic oscillator, where the gain and loss modes are confined in a single spatial resonator, resulting in an increased structural simplicity, and long-term stability.

FPGAs have long been of interest as reconfigurable circuits, but their electronic nature provides eventual limitations. Here the authors demonstrate a photonic digital signal processor that is field programmable using arrays of microdisk resonators.

BackgroundSerum creatinine, an important diagnostic indicator for acute kidney injury (AKI), was considered to be a risk factor for cardiovascular disease. This study aimed to investigate the significance of postoperative serum creatinine in predicting the prognosis of cardiac surgery patients.MethodsThe Medical Information Mart for Intensive Care III (MIMIC-III) database was used to extract the clinical data. Adult (≥18 years) cardiac surgery patients in the database were enrolled. The correlation of postoperative serum creatinine with lengths of intensive care unit (ICU) stay was analyzed with Spearman correlation, and the association of postoperative serum creatinine with hospital mortality was analyzed with chi-square tests. Multivariable logistic regression was used to identify postoperative serum creatinine as an independent prognostic factor for hospital mortality.ResultsA total of 6,001 patients were enrolled in our study, among whom, 108 patients (1.8%) died in the hospital. Non-survivors had much higher postoperative serum creatinine levels (initial: 0.8 vs. 1.2 mg/dl, P < 0.001; maximum: 1.1 vs. 2.8 mg/dl, P < 0.001; minimum: 0.8 vs.1.1 mg/dl, P < 0.001). Positive correlations were observed between postoperative serum creatinine (P < 0.001) and lengths of ICU stay. For all models, postoperative initial creatinine, postoperative maximum creatinine, and postoperative minimum creatinine were all positively associated with hospital mortality (all P < 0.001). The predictive performance of postoperative serum creatinine was moderately good (area under the curve (AUC) for initial creatinine = 0.7583; AUC for maximum creatinine = 0.8413; AUC for minimum creatinine = 0.7063).ConclusionsThis study demonstrated the potential to use postcardiac surgery serum creatinine as an outcome indicator.

Aims: To explore the value of preoperative liver function tests (LFTs) for the prognosis of cardiac surgery patients without liver disease.Methods: The Medical Information Mart for Intensive Care III (MIMIC-III) database was used to extract the clinical data. Adult cardiac patients (≥18 years) without liver disease in the database were enrolled. The association of LFTs with the time of hospital stay and ICU stay was analyzed with the Spearman correlation. Survival curves were estimated using the Kaplan-Meier method and compared by the log-rank test. Multivariable logistic regression was used to identify LFTs that were independent prognostic factors of mortality.Results: A total of 2,565 patients were enrolled in this study. Albumin (ALB) was negatively associated with the time of hospital stay and ICU stay, while alanine transaminase (ALT), aspartate aminotransferase (AST), and total bilirubin were positively associated with the time of hospital stay and ICU stay (all p < 0.001). Abnormal ALB, ALT, AST, and total bilirubin were associated with lower 90-day and 4-year survival (all p < 0.001) and could be used as independent risk factors for hospital mortality and 90-day mortality. However, only ALB and total bilirubin were independent risk factors for 4-year mortality.Conclusion: Preoperative LFT abnormalities were associated with short-term and long-term prognosis of cardiac surgery patients without liver disease.

We propose and experimentally demonstrate an approach to carrier frequency and phase recovery of a microwave photonic signal based on carrier period measurement (CPM). In the approach, a coarse carrier frequency offset (CFO) estimation is first performed, which is realized by measuring the crossing period of the microwave signal with its mean level. Then, an envelope detection method is used to simultaneously estimate the residual CFO and the carrier phase. Through the two steps, wideband and high-accuracy carrier recovery can be realized. The proposed approach is validated by an experiment. Effective carrier recovery of a microwave photonic signal is achieved with a carrier frequency varying from 7 to 37 GHz carrying a 2-Gbaud on-off-keying or quadrature phase shift keying baseband signal. The CFO estimation range is from -21 to +9 GHz, and the CFO estimation errors are less than 0.1 MHz.

In optoelectronic oscillators used to produce chirps for radar or communications, low phase noise usually comes at a cost of slow tuning due to mode-building time. The authors use Fourier-domain mode locking to break this limitation and enable fast-tunable chirp production for microwave photonics.