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Numerous modern technologies are reliant on the low-phase noise and exquisite timing stability of microwave signals. Substantial progress has been made in the field of microwave photonics, whereby low-noise microwave signals are generated by the down-conversion of ultrastable optical references using a frequency comb 1 – 3 . Such systems, however, are constructed with bulk or fibre optics and are difficult to further reduce in size and power consumption. In this work we address this challenge by leveraging advances in integrated photonics to demonstrate low-noise microwave generation via two-point optical frequency division 4 , 5 . Narrow-linewidth self-injection-locked integrated lasers 6 , 7 are stabilized to a miniature Fabry–Pérot cavity 8 , and the frequency gap between the lasers is divided with an efficient dark soliton frequency comb 9 . The stabilized output of the microcomb is photodetected to produce a microwave signal at 20 GHz with phase noise of −96 dBc Hz −1 at 100 Hz offset frequency that decreases to −135 dBc Hz −1 at 10 kHz offset—values that are unprecedented for an integrated photonic system. All photonic components can be heterogeneously integrated on a single chip, providing a significant advance for the application of photonics to high-precision navigation, communication and timing systems. We leverage advances in integrated photonics to generate low-noise microwaves with an optical frequency division architecture that can be low power and chip integrated.

When the retina is constantly affected by high glucose (HG) due to diabetes, the barrier function of the retinal pigment epithelium (RPE) is impaired, accompanied by unnecessary vascularization. This eventually leads to the development of diabetic retinopathy (DR). This study investigated the recovery effect of substance P (SP) on RPE injured by HG. RPE was treated with HG for 24 h, and HG-induced cellular injuries were confirmed. SP was added to the dysfunctional RPE. Compared to RPE in low glucose (LG) conditions, HG-damaged RPE had large, fibrotic cell shapes, and its cellular viability decreased. HG treatment reduced tight junction protein expression levels and caused oxidative stress by interrupting the antioxidant system; this was followed by inflammatory factor intracellular adhesion molecule-1 (ICAM-1), Monocyte chemotactic protein-1 (MCP-1), and angiogenesis factor vascular endothelial growth factor (VEGF) expression. SP treatment contributed to RPE recovery by enhancing cell viability, tight junction protein expression, and RPE function under HG conditions, possibly by activating the Akt signaling pathway. Importantly, SP treatment reduced ICAM-1, MCP-1, and VEGF expression. Collectively, SP activated survival signals to suppress oxidative stress and improve retinal barrier function in RPE, accompanied by immune suppression. This suggests the possible application of SP to diabetic retinal injuries.

Twelve undescribed peptidic compounds, bukhansantaibols A–K (1–10) and bukhansantaibals A–B (11–12), were isolated from the soil fungus Trichoderma atroviride through LC-MS and bioactivity-guided purification. Their structures were elucidated by the analysis of 1D and 2D NMR spectra, HRESIMS, and acid hydrolysis using modified Marfey’s method. All compounds were evaluated for their cytotoxic activity against HCT-8 (colon cancer) and SK-OV-3 (ovarian cancer) cells. Among them, compounds 1–5 exhibited significant inhibitory effects, with IC50 values ranging from 2.1 to 19.6 μM.

Highly frequency-stable lasers are ubiquitous tools for optical-frequency metrology, precision interferometry, and quantum information science. While making a universally applicable laser is unrealistic, spectral noise can be tailored for specific applications. Here we report a high-power 698-nm clock laser with a maximum output of 4W and minimized frequency noise up to a few kHz Fourier frequency, together with long-term instability of 3.5 × 10 − 17 at one to thousands of seconds. The laser-frequency noise is precisely characterized with atom-based spectral analysis that employs a pulse sequence designed to suppress sensitivity to intensity noise. This method provides universally applicable tunability of the spectral response and analysis of quantum sensors over a wide frequency range. With the optimized laser system characterized by this technique, we achieve an average single-qubit Clifford gate fidelity of up to F 1 2 = 0.999 64 ( 3 ) when simultaneously driving 3000 optical qubits with a homogeneous Rabi frequency ranging from 10 Hz to 1 kHz. This result represents the highest single optical-qubit-gate fidelity for a large number of atoms.

Despite the steadily increasing prevalence of female smoking, gender-responsive tobacco cessation services have not been widely provided worldwide. The purpose of this study is to identify factors associated with the use of tobacco cessation services among female tobacco product users in Korea from a national perspective. We performed a logistic regression analysis using data from 663 female smokers; 11.0% of female smokers had used government-supported smoking cessation services. A logistic regression model showed a statistically significant association between the utilization of smoking cessation services and a history of pregnancy and childbirth, depression, current use of heated tobacco products and multiple tobacco products, parental smoking status and receiving advice to quit. With regard to the motivation ruler, those in their 50s reported a higher importance than those in their 20s. Weight gain concerns when quitting smoking were the lowest among the participants aged 19–29. The need to develop gender-specific smoking cessation programs is the highest among the participants aged 39–49 and the lowest among those aged 19–29. This study suggests several factors related to the utilization of national health services among female smokers. Further studies considering gender-specific needs for the development of gender-responsive tobacco cessation support are needed.

Liver failure is an outcome of chronic liver disease caused by steatohepatitis and cholestatic injury. This study examined substance P (SP) effect on liver injury due to cholestatic stress caused by excessive bile acid (BA) accumulation. Chenodeoxycholic acid (CDCA) was added to HepG2 cells to induce hepatic injury, and cellular alterations were observed within 8 h. After confirming BA-mediated cellular injury, SP was added, and its restorative effect was evaluated through cell viability, reactive oxygen species (ROS)/inflammatory cytokines/endothelial cell media expression, and adjacent liver sinusoidal endothelial cell (LSEC) function. CDCA treatment provoked ROS production, followed by IL-8 and ICAM-1 expression in hepatocytes within 8 h, which accelerated 24 h post-treatment. Caspase-3 signaling was activated, reducing cell viability and promoting alanine aminotransferase release. Interestingly, hepatocyte alteration by CDCA stress could affect LSEC activity by decreasing cell viability and disturbing tube-forming ability. In contrast, SP treatment reduced ROS production and blocked IL-8/ICAM-1 in CDCA-injured hepatocytes. SP treatment ameliorated the effect of CDCA on LSECs, preserving cell viability and function. Collectively, SP could protect hepatocytes and LSECs from BA-induced cellular stress, possibly by modulating oxidative stress and inflammation. These results suggest that SP can be used to treat BA-induced liver injury.

In many cases, optical systems exhibit orders of magnitude improved performance over their microwave counterparts. For example, optical clocks have much better stability than microwave clocks, and generating picosecond pulses is easy in optics while it is very challenging with electronics. The field of microwave photonics aims to bring such advantages of optical systems to the microwave domain, achieving performance levels beyond the capabilities of conventional electronics. In the work presented here, we show how microwave photonics can be harnessed for low noise microwave generation and cryogenic applications. For low noise microwaves, focus is given to the behavior of photodiode flicker noise, the dominant noise contributor at long timescales, under short pulse illumination. Due to the cyclostationary nature of the noise process, flicker phase noise was found to be lower than flicker amplitude noise by as much as 10 dB, in agreement with our noise model. The cryogenic photonic link experiments were performed with the goal of driving Josephson junction arrays with photonically generated electrical pulse patterns, as required for producing AC voltage standards. This approach can potentially achieve system bandwidths as wide as 100 GHz, which is very difficult to achieve in cryogenic systems driven with traditional methods. With optically driven Josephson junctions, we synthesized a 1 kHz bipolar sine wave. An optical arbitrary pulse pattern generator based on a 2D line-by-line pulse shaper is also shown. The pulse shaper exhibits the highest resolution among programmable pulse shapers of similar designs. With these experiments, we show how microwave photonics can continue to push the state-of-the-art in low noise microwave generation and high-bandwidth signal generation in cryogenic environments.

Background: This study was conducted to evaluate the relationship of job stress, burnout, and resilience of 271 nurses who worked alternately at a university hospital in South Korea Province and a state-designated inpatient ward for COVID-19 in Korea. Methods: The study sample included nurses who worked at a university hospital in South Korea, during the period between February 2020 and May 2021. The participants (n = 271) responded to an online survey between April 2021 and 12 May 2021. The questionnaire included information related to job stress, burn out, and resilience. Results: In phase 1 of regression, job stress had a significant negative effect on resilience of recovery (β = −0.397, p < 0.001). In phase 2, job stress had a significant positive effect on burnout (β = 0.513, p < 0.001). In phase 3, resilience had a significant negative effect on burnout (β = −0.459, p < 0.001). Seventy-five percent of burnout was directly associated with job stress, while 25% of burnout was indirectly associated through mediated effects, through resilience. Conclusions: The promotion of resilience would not only serve as the basis for active coping in situations where burnout and stress are severe, but also serve as a basic driving force for actively overcoming them. Further study to cope with stress and reduce burnout at the organizational level should be conducted.

Adolescence is a crucial period for cognitive and psychological development and physical maturation. During this period, hormonally influenced circadian rhythms lead to reduced hours of sleep, and it is important to determine whether sleep quality is sufficient for fatigue relief. Non-face-to-face classes during coronavirus disease-2019 (COVID-19) potentially affected adolescents’ sleep quality, psychological state, amount of physical activity, smoking, alcohol consumption, and internet (smartphone) use. We investigated the effects of the COVID-19 situation on adolescents’ sleep satisfaction and its relation to the aforementioned factors. Data of 109,281 adolescents collected via an online survey, conducted from 3 June 2019 to 12 July 2019 and from 3 August 2020 to 13 November 2020, were analyzed. Health status comparison between the satisfactory and unsatisfactory sleep groups yielded significant results (odds ratio [OR] = 1.10, confidence interval [CI] = 1.04–1.17) for 2020. In both groups, perceived health was worse in 2019 than in 2020 (OR = 2.72, CI = 2.53–2.92). During COVID-19, non-face-to-face classes increased adolescents’ sleep satisfaction. Their psychological state improved, while amount of physical activity (muscle-strengthening exercises), average weight, and internet (smartphone) use increased. Smoking and alcohol consumption decreased.

Numerous modern technologies are reliant on the low-phase noise and exquisite timing stability of microwave signals. Substantial progress has been made in the field of microwave photonics, whereby low-noise microwave signals are generated by the down-conversion of ultrastable optical references using a frequency comb13. Such systems, however, are constructed with bulk or fibre optics and are difficult to further reduce in size and power consumption. In this work we address this challenge by leveraging advances in integrated photonics to demonstrate low-noise microwave generation via two-point optical frequency division4,5. Narrow-linewidth self-injection-locked integrated lasers6,7 are stabilized to a miniature Fabry-Perot cavity8, and the frequency gap between the lasers is divided with an efficient dark soliton frequency comb9. The stabilized output of the microcomb is photodetected to produce a microwave signal at 20 GHz with phase noise of-96 dBc Hz1 at 100 Hz offset frequency that decreases to -135 dBc Hz1 at 10 kHz offset-values that are unprecedented for an integrated photonic system. All photonic components can be heterogeneously integrated on a single chip, providing a significant advance for the application of photonics to high-precision navigation, communication and timing systems.