Flexible wavelength-, pulse-controlled mode-locked all-fiber laser based on a fiber Lyot filter.

In this paper, we report a flexible wavelength-, pulse-controlled mode-locked all-fiber laser based on a novel fiber optic Lyot filter. The wavelength, pulse duration and spectral bandwidth of passive mode-locked lasers can be tuned by controlling the polarization controller. The proposed Lyot filter was constructed by a single-mode fiber insertion between two polarization-maintaining fibers. The filter bandwidth and laser output tunability were based on the birefringence characteristics of the polarization-maintaining fibers. This all-fiber laser is simple and stable and can be used for various applications where width-tunable or wavelength-tunable pulses are necessary.

Ultra-broadband flat-top circular polarizer based on chiral fiber gratings near the dispersion turning point.

Based on the dual-resonance principle around the dispersion turning point, a scheme of chiral long-period fiber gratings (CLPGs) formed by twisting a high-birefringence (Hi-Bi) fiber is herein proposed to realise ultra-broadband flat-top circular polarizers. The coupling bandwidth is approximately seven times larger than that of traditional CLPGs. In addition, by introducing chirp characteristics in these CLPGs, an ultra-broadband flat-top circular polarizer with ∼200 nm@3 dB was conveniently achieved. Subsequently, by optimising the chirped CLPGs, a circular polarizer with a bandwidth extinction ratio of approximately 30 dB and a high level of ∼100 nm at 1 dB was realised. It was shown that the mode-controlling performances of the CLPGs can be remarkably improved, which has significant applications in light-field regulation. Finally, for the first time, it was proved that the CLPG cannot generate a vortex beam.

Abnormal Liver Function Tests Were Associated With Adverse Clinical Outcomes: An Observational Cohort Study of 2,912 Patients With COVID-19.

Background and Aim: The impact of liver function test (LFTs) abnormality on adverse clinical outcomes in coronavirus disease 2019 (COVID-19) patients remains controversial. The aim of this study was to assess the impact of abnormal LFTs on clinical outcomes in a large cohort of hospitalized patients with COVID-19. Methods: We retrospectively collected data on 2,912 consecutive patients with COVID-19 who were admitted to a makeshift hospital in China between 5 February and 23 March 2020. The association between LFTs abnormalities (baseline and peak values) and clinical outcomes was measured by using Cox regression models. Results: On admission 1,414 patients (48.6%) had abnormal LFTs, with alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), alkaline phosphatase (ALP), and gamma-glutamyltransferase (GGT) elevation in 662 (22.7%), 221 (7.6%), 52 (1.8%), 135 (4.6%), and 536 (18.5%) patients, respectively, and hypoalbuminemia in 737 (25.3%) patients. During a median 13 (IQR: 8-19) days of hospitalization, 61 patients (2.1%) died, 106 patients (3.6%) admitted to intensive care unit (ICU), and 75 patients (2.6%) required mechanical ventilation. After adjustment for confounders, baseline abnormal LFTs were independently associated with increased risks of mortality (adjusted HR 3.66, 95%CI 1.64-8.19, p = 0.002), ICU admission (adjusted HR 3.12 95%CI 1.86-5.23, p < 0.001), and mechanical ventilation (adjusted HR 3.00, 95%CI 1.63-5.52, p < 0.001), which was homogeneous across the severity of COVID-19 infection. Among the parameters of LTFs, the associations with the outcomes were more pronounced for AST and albumin abnormality. In contrast, ALT elevation was not significantly associated with those outcomes. Similar results were observed for peak values of LFTs during hospitalization. Conclusions: Abnormality of AST, albumin, TBIL, ALP, and GGT but not ALT were independently associated with adverse outcomes.

Diagnosis of liquid-gas mixed sprays in the near-field region using femtosecond laser induced supercontinuum imaging method.

Direct femtosecond shadowgraphy and supercontinuum (SC)-illumination imaging methods for diagnosing liquid-gas mixed sprays in the near-field region of spray nozzles were compared. Some big spray structures can be captured using femtosecond shadowgraphy which can freeze the motion of the sprays. But the speckles caused by the interference of multi-scattered photons erode the edges of ligaments and conceal many fine droplets. SC-illumination imaging can not only freeze the motion of the sprays but also significantly suppressing the speckles, presenting a more realistic spray pattern. Based on the SC imaging technology, the effects of various factors such as flow ratio of gas to liquid (GLR), total flow and nozzle size on the spray were studied.

2,3,5,4'-Tetrahydroxystilbene-2-O-ß-d-glucoside alleviated the acute hepatotoxicity and DNA damage in diethylnitrosamine-contaminated mice.

AIMS: 2,3,5,4'-Tetrahydroxystilbene-2-O-ß-d-glucoside (TSG) is the key bioactive ingredient extracted from Polygonum multiflorum Thumb. Pharmacological studies suggest that it exerts numerous biological effects, including anti-oxidant, anti-aging, and anti-inflammation. This study aimed at investigating the effect of TSG on diethylnitrosamine (DEN)-induced acute hepatotoxicity and DNA damage. MAIN METHODS: Fifty male C57BL/6 mice were randomly divided into 5 groups (n = 10 each): control, DEN, DEN+TSG (low), DEN+TSG (high) and TSG (high) groups. DEN (100 mg/kg) was injected intraperitoneally (i.p.) alone or with TSG (30 or 60 mg/kg, i.p.) for 5 consecutive days. KEY FINDINGS: TSG inhibited liver injury and inflammatory cell infiltration in DEN-treated mice. It also attenuated DEN-induced accumulation of reactive oxygen species (ROS), proinflammatory cytokines, and DNA damage. Moreover, TSG promoted the expression of nuclear erythroid 2-related factor 2 (Nrf2) target antioxidant genes by enhancing Nrf2 protein phosphorylation and nuclear translocation. As major phase I detoxification enzymes, cytochrome P450 family 2 subfamily E member 1 (CYP2E1) and cytochrome P450 1 subfamily A member 1 (CYP1A1) are responsible for the metabolic activation of DEN. We found that TSG administration inhibited CYP2E1 and CYP1A1 induction in DEN-treated mice. SIGNIFICANCE: These results indicate that TSG can alleviate DEN-induced acute hepatotoxicity by modulating the Nrf2-related antioxidant system and metabolic activation of DEN. Therefore, TSG might be a promising medication for DEN-induced liver injury treatment.

Comparison of femtosecond shadowgraphy and optical Kerr gated ballistic imaging for measurements of spray structures.

Two femtosecond methods for imaging moderate liquid-gas sprays in the near-field region of spray nozzles - shadowgraphy and optical Kerr gated (OKG) ballistic imaging - were compared. Most spray structures can be captured using femtosecond shadowgraphy that can freeze the motion of the sprays. Femtosecond OKG ballistic imaging can distinguish finer structures and more-realistic liquid sheets by the filtering of multiple scattered photons. To compensate for the high-spatial-frequency components of the spray structures filtered by OKG ballistic imaging, differential OKG (DOKG) ballistic imaging was demonstrated. For dilute sprays, femtosecond shadowgraphy with a relatively simple experimental setup is recommended. For dense sprays, femtosecond OKG (or DOKG) ballistic imaging is more suitable.

Ballistic imaging through an intense scattering medium using a supercontinuum with a roundabout spatial gate.

We propose a new ballistic imaging method that is capable of imaging an object through an intense scattering medium. In this method, a femtosecond supercontinuum and a roundabout spatial gate were used to suppress speckles and filter background noise, respectively. The roundabout spatial gate extracts ballistic light and avoids low-pass spatial filtering to ensure the high resolution of images. The experimental results showed that even when the optical depth of the scattering medium reached 17, the images extracted by the method had improved identifiability and contrast.

Speckle-suppressed full-field imaging through a scattering medium using a supercontinuum.

We demonstrate speckle-suppressed full-field imaging through a scattering medium using incoherent supercontinuum (SC) illumination. The patterns in images obtained using SC illumination were found to be more easily identifiable than those in images acquired using coherent direct laser illumination due to the speckle suppression. Even when the optical depth reached 12.3, the patterns remained identifiable. As one of the potential applications, we also demonstrated the imaging for a high-pressure diesel spray using SC illumination.

Long-working-distance microscopic imaging in a turbid medium by use of an ultrafast optical Kerr gate.

We demonstrate a long-working-distance microscopic imaging of hidden objects in a turbid medium by use of an ultrafast optical Kerr gate (OKG). The results show that the working distance and the spatial resolution of the long-working-distance microscopic imaging system have been increased simultaneously compared with those of the conventional 4f OKG imaging systems. A compound lens consisting of a long-focus achromatic doublet and a microscope objective is used to increase the long working distance and ensure the sufficient spatial resolution. The microscopic OKG imaging system with a working distance of 245 mm and a maximal spatial resolution of approximately 7 µm has been performed.

Inhibition of FOXM1 by thiostrepton sensitizes medulloblastoma to the effects of chemotherapy.

Medulloblastoma (MB) is the most common malignant brain tumor in children and is highly invasive and metastatic. Despite recent advances, most MB patients suffer significant therapy-related morbidity, and the survival rate for patients with metastatic MB remains unsatisfactory. Altered expression of FOXM1 has been detected in many types of cancers, and the inhibition of FOXM1 has been studied as a cancer therapy. In the present study, we evaluated the impact of the inhibition of FOXM1 by thiostrepton in Daoy MB cells. Cells were treated with different concentrations of thiostrepton alone or in combination with cisplatin. Cell viability was measured with CCK-8 assays, and cell cycle distribution and apoptosis were assessed by flow cytometric analysis. Changes in protein expression were examined by western blotting. RNAi experiments were performed using siRNA oligonucleotides. The invasion and migration studies were performed using 8-µm Transwell plates. Inhibition of FOXM1 by thiostrepton significantly decreased MB cell proliferation. Cell arrest at the G2/M phase and apoptosis were significantly increased in MB cell lines that were treated with thiostrepton or transfected with siRNA. Thiostrepton decreased the IC50 value of cisplatin for MB treatment by enhancing cisplatin-induced apoptosis. Thiostrepton also decreased cell invasion and migration, which are crucial steps for tumor progression. Our data suggest that targeting FOXM1 with small-molecule inhibitors results in potent antitumor activity and chemosensitizing effects in human medulloblastoma cells.