Emission of five OAM dispersive waves in dispersion-engineered double-ring core fiber.

Beams carrying orbital angular momentum (OAM) have exhibited significant potential across various fields, such as metrology, image coding, and optical communications. High-performance broadband coherent OAM sources are critical to the operation of optical systems. The emission of dispersive waves facilitates the efficient transfer of energy to distant spectral domains while preserving the coherence among the generated frequency components. Light sources that maintain consistency over a wide range can increase the efficiency of optical communication systems and improve the measurement accuracy in imaging and metrology. In this work, we propose a germanium-doped double ring-core fiber for five OAM dispersive waves (DWs) generation. The OAM1,1 mode supported in the fiber exhibits three zero-dispersion wavelengths (ZDWs) located at 1275, 1720 and 2325 nm. When pumped under normal dispersion, the output spectrum undergoes broadening and exhibits five DWs, situated around 955, 1120, 1450, 2795 and 2965 nm, respectively. Concomitant with blue-shifted and red-shifted dispersive waves, the spectrum spans from 895 to 3050 nm with high coherence. The effect of the fiber and input pulse parameters on DWs generation, as well as the underlying dynamics of the dispersive wave generation process, are discussed. As expected, the number and location of DWs generated in the output spectrum have agreement with the prediction of the phase-matching condition. Overall, this multiple DWs generation method in the proposed fiber paves the way for developing efficient and coherent OAM light sources in fiber-based optical systems.

Solid-state Lidar with wide steering angle using counter-propagating beams.

In a solid-state photonics-based Lidar, all essential components can be integrated into a silicon chip. It is simple and effective to use a tunable laser source to implement Lidar's beam steering. However, how to effectively increase the steering angle in a small wavelength tuning range is usually a key challenge due to the limited material and waveguide dispersion. In Silicon-on-insulator waveguide, we design a novel solid-state Lidar using two trans-electrical (TE) polarized beams counter-propagating towards each other. Two corresponding output beams from just a single grating coupler (GC) can be seamlessly combined to double the beam steering angle. Furthermore, a low-priced solid-state Lidar is designed for TE polarized beams counter-propagating towards each other by using wavelength division multiplexed laser array.

A photoactivated H2S donor based on a coumarin structure with real-time monitoring capability.

Attaining controlled, biocompatible H2S donors poses significant challenges. We developed Bhc-TCN-Ph, a photoactivated H2S donor derived from 6-bromo-7-hydroxycoumarinmethyl thiocarbonate. Upon 365 nm light exposure, COS is released, generating H2S and coumarin fluorescence for visualization. This process produces no electrophilic by-products. In vitro evaluations reveal good cytochemical and cytocompatibility characteristics.

Sleep Characteristics in Older Adults with Different Levels of Risk for Dementia: A Cross-sectional Study.

BACKGROUND: Sleep problems are very prevalent in older adults, especially in those at risk for dementia. But the relationships between sleep parameters and subjective or objective cognitive decline are still inconclusive. AIM: The study aimed to investigate the self-reported and objectively measured sleep characteristics in older adults with mild cognitive impairment (MCI) and subjective cognitive decline (SCD). METHODS: This study adopted a cross-sectional design. We included older adults with SCD or MCI. Sleep quality was measured separately by the Pittsburgh sleep quality index (PSQI) and ActiGraph. Participants with SCD were divided into low, moderate, and high levels of SCD groups. Independent samples T-tests, one-way ANOVA, or nonparametric tests were used to compare the sleep parameters across groups. Covariance analyses were also performed to control the covariates. RESULTS: Around half of the participants (45.9%) reported poor sleep quality (PSQI＜7), and 71.3% of participants slept less than 7 hours per night, as measured by ActiGraph. Participants with MCI showed shorter time in bed (TIB) (p＜0.05), a tendency of shorter total sleep time (TST) at night (p = 0.074) and for each 24-hour cycle (p = 0.069), compared to those with SCD. The high SCD group reported the highest PSQI total score and longest sleep latency than all the other three groups (p＜0.05). Both the MCI and high SCD groups had shorter TIB and TST for each 24-hour cycle than the low or moderate SCD groups. Besides, participants with multiple-domain SCD reported poorer sleep quality than those with single-domain SCD (p＜0.05). CONCLUSION: Sleep dysregulation is prevalent in older adults with a risk for dementia. Our findings revealed that objectively measured sleep duration might be an early sign of MCI. Individuals with high levels of SCD demonstrated poorerself-perceived sleep quality and deserved more attention. Improving sleep quality might be a potential target to prevent cognitive decline for people with a risk for dementia.

Shaoyao decoction restores the mucus layer in mice with DSS-induced colitis by regulating Notch signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Restoring the mucus layer is a potential strategy for treating ulcerative colitis (UC). Previous studies reported that a Chinese medicine formula Shaoyao Decoction (SYD) effectively improved UC. However, the role and mechanism of SYD in restoring the mucus layer are still vague. AIM OF THE STUDY: This study aimed to research the therapeutical effects and unravel the involved mechanism of SYD on DSS-evoked UC. MATERIALS AND METHODS: First, the constituents of SYD were detected by UPLC-QTOF-MS/MS. Then, the DSS-induced UC model was introduced to investigate the pharmacologic action and molecular mechanism of SYD on UC. Pharmacodynamic indicators were assessed including body weight, colon length, ulcerations, disease activity index (DAI), inflammatory cytokines and histological parameters. To investigate the integrality and functions of the mucous layer, AB-PAS stain and UEA-1 stain were used to evaluate the completeness of mucous layer, as well as the maturation of goblet cells (GCs). The bacterial invasion was detected by fluorescence in situ hybridization. As to mechanism exploration, the expressions of Notch/Hes1 pathway were investigated by using agonists in lipopolysaccharides (LPS) -stimulated LS174T cell. RESULTS: After modeling in mice, SYD remarkedly ameliorated the symptoms of mouse colitis, the expression of pro-inflammatory factors declined, and increased IL-10 expression was observed in SYD-treated mice. Besides, SYD repaired the structure of the mucus layer and prevented bacterial invasion. Mechanism investigation discovered that SYD promoted GCs differentiation by inhibiting the Notch pathway, which was consistent with the results in LPS-challenged LS174 cell. CONCLUSIONS: These findings demonstrated that SYD could restore the mucus layer to prevent UC via suppressing the Notch signaling pathway, which provided evidences for the UC treatment of SYD in the clinic.

Broadband dispersion compensating ring-core fiber for orbital angular momentum modes.

A well designed ring-core fiber can theoretically support numerous orbital angular momentum (OAM) modes with low crosstalk for space-division-multiplexing (SDM) data transmission, which is considered as a promising solution for overcoming the capacity crunch in optical communication network. However, the accumulated chromatic dispersion in OAM-fiber could limit the data speed and transmission distance of communication systems. A potential solution is to insert a dispersion compensation ring-core fiber with opposite-sign of dispersion in the transmission fiber along the fiber link. In this work, we propose a triple ring-core fiber with broadband negative dispersion. A highest negative dispersion of -24.47 ps/(nm·km) at 1550 nm and an average dispersion slope in the C band from -0.182 ps/(nm2·km) to 0.065 ps/(nm2·km) can be achieved to compensate multi-order dispersion. The effects of Ge-doping concentration fluctuation in the high-index ring core and fabrication errors on fiber geometric structures are also investigated. Furthermore, the effective mode area decreases as the widths of high-index rings increase due to the enhanced confinement ability. The designed triple ring-core fiber could offer potential for compensating OAM fiber links with positive dispersions.

Aloin A prevents ulcerative colitis in mice by enhancing the intestinal barrier function via suppressing the Notch signaling pathway.

BACKGROUND: Previous studies reported that Aloe vera ameliorated DSS-induced colitis and promoted mucus secretion. However, the effect of Aloin A (AA), a major compound of Aloe vera, on colitis and its exact mechanism remains uncovered. METHODS: C57BL/6 mice were successively subjected to 3% DSS solution for 5 days and distilled water for 2 days. Concurrently, AA (25, 50 mg/kg) and 5-aminosalicylic (500 mg/kg) were administrated intragastrically from day 1 to day 7. Colitis was evaluated by disease active index (DAI), colon length, inflammation response, and intestinal barrier function. In vitro LS174T cells challenged with 50 ng/ml of lipopolysaccharides (LPS) were used to validate the modulatory action of AA on the Notch signaling pathway. RESULTS: Our results showed that oral administration with AA prominently prevented DSS-induced colitis symptoms in terms of decreased DAI, prevention of colon shortening, and reduced pathological damage. AA mitigated the inflammatory response evidenced by the decreased proinflammatory cytokines (TNF-α, IL-1ß, IL-6) and increased anti-inflammatory cytokine (IL-10). Besides, AA inhibited apoptosis and facilitated proliferation in colons. Moreover, AA treatment up-regulated the expression of tight junction (TJ) proteins (ZO-1, Occludin) and promoted the secretion of MUC2 to decrease colon permeability. Mechanistically, AA inhibited the Notch pathway to promote the secretion of MUC2, which was consistent with LPS-challenged LS174 cells. CONCLUSION: These results suggested that AA could prevent colitis by enhancing the intestinal barrier function via suppressing the Notch signaling pathway. Thus, AA might be a prospective remedy for ulcerative colitis.

Over-Two-Octave Supercontinuum Generation of Light-Carrying Orbital Angular Momentum in Germania-Doped Ring-Core Fiber.

In this paper, we design a silica-cladded Germania-doped ring-core fiber (RCF) that supports orbital angular momentum (OAM) modes. By optimizing the fiber structure parameters, the RCF possesses a near-zero flat dispersion with a total variation of <±30 ps/nm/km over 1770 nm bandwidth from 1040 to 2810 nm for the OAM1,1 mode. A beyond-two-octave supercontinuum spectrum of the OAM1,1 mode is generated numerically by launching a 40 fs 120 kW pulse train centered at 1400 nm into a 12 cm long designed 50 mol% Ge-doped fiber, which covers 2130 nm bandwidth from 630 nm to 2760 nm at −40 dB of power level. This design can serve as an efficient way to extend the spectral coverage of beams carrying OAM modes for various applications.

Application of traditional Chinese medicine syndrome differentiation in identification of body constitution of hypertensive and diabetic patients.

OBJECTIVE: To investigate the application of traditional Chinese medicine (TCM) syndrome differentiation in identification of body constitution of hypertensive and diabetic patients. METHODS: A total of 110 hypertensive patients with diabetes treated in our hospital were enrolled in this study, and were divided into a study group (SG, n=60) and a control group (CG, n=50) according to different intervention methods. Patients in the CG received conventional western medical intervention for hypertension and diabetes, while patients in the SG received body constitution-identified TCM syndrome differentiation intervention additionally. The changes of blood pressure and plasma glucose during the intervention were compared between the two groups, the clinical effect and quality of life of the two groups were evaluated, and multivariate stepwise Logistic regression analysis on influencing factor of TCM body constitution was conducted. RESULTS: Compared with that before intervention, the proportion of gentleness constitution in the SG showed a significant increase (P<0.05) after intervention. Dynamic analysis during the intervention showed that patients in the SG had lower systolic blood pressure (SBP), diastolic blood pressure (DBP), lower level of fasting plasma glucose (GLU) and 2-h postprandial plasma glucose (2hPG) than the CG from 1 to 12 months after intervention (P<0.05). Patients in the SG scored higher than the CG on all SF-36 dimensions after intervention (P<0.05). Multivariate stepwise Logistic regression analysis showed that dampness-heat constitution, blood-stasis constitution, Yin-deficiency constitution and phlegm-dampness constitution were the main risk factors for hypertension with diabetes (P<0.05). CONCLUSION: Body constitution-identified TCM syndrome differentiation treatment for hypertensive patients with diabetes is effective, which can significantly improve the plasma glucose and blood pressure indices of patients. Dampness-heat constitution, blood-stasis constitution, Yin-deficiency constitution and phlegm-dampness constitution are the risk factors for hypertension with diabetes.

Non-zero dispersion-shifted ring fiber for the orbital angular momentum mode.

As the dimension of orbital angular momentum (OAM) is orthogonal to the other degrees of freedom for photon, such as wavelength, it can be utilized to further increase data capacity in the wavelength division multiplexing (WDM) systems. However, the non-zero dispersion-shifted fiber (NZDSF) for the OAM mode has not yet been investigated or even proposed. In this work, we propose and design a ring fiber with low chromatic dispersion for the HE2,1 mode, which can serve as NZDSF for its corresponding OAM1,1 mode. A low dispersion of 3.3 ps/(nm·km) at 1550 nm and <2.9 ps/(nm·km) dispersion variation from 1530 to 1565 nm for the OAM1,1 mode is achieved in simulation, which satisfies the standard of the ITU-T G.655.C. The designed fiber with ring width from 1.5 µm to 3.5 µm can support the OAM1,1 mode within the C-band, and a large effective area of about 646 µm2 is obtained. We also note that the fiber with larger inner radius and ring width are more tolerant to the perturbations, such as fiber ellipticity and bending. In the fiber-based optical communication systems, the designed ring fiber could be used as a candidate for supporting OAM modes with low dispersion and reduced nonlinear effects.

Seven air-core fibers with germanium-doped high-index rings supporting hundreds of OAM modes.

In this paper, we propose and design a multi-orbital-angular-momentum multi-ring air-core fiber, which has seven high-index rings with each ring supporting 62 radially fundamental OAM modes across C and L bands (from 1530 nm to 1625 nm), i.e. 434 OAM modes in total. The designed fiber features >4×10-4 intra-ring modal indices difference for OAM modes with the same topological charge l in a ring across the C and L bands. Moreover, it can keep <-52 dB crosstalk between the OAM modes in the adjacent rings at 1550 nm, and <-24 dB crosstalk across C and L bands after 100-km fiber propagation. This kind of seven-air-core-ring fiber would be a robust candidate for transmitting efficient OAM modes and boosting the capacity of optical fiber communications systems.

Small-molecule probes for fluorescent detection of cellular hypoxia-related nitroreductase.

Nitroreductase is a reductase that catalyzes nitro aromatic compounds to aromatic amines. It effectively reduces nitro to hydroxylamine or amino when in the presence of nicotinamide adenine dinucleotide or nicotinamide adenine dinucleotide phosphate. In terms of tumor, nitroreductase is upregulated in hypoxic tumor cells, and its content is directly related to the degree of hypoxia. Therefore, effective detection of nitroreductase is important not only for the study of cellular hypoxia, but also for the diagnosis and treatment of tumors and related diseases. In this review, we summarized the latest advances in small-molecule fluorescent probes for nitroreductase detection based on different fluorescence mechanisms, with a focus on research conducted between May 2018 and December 2020. The development trends and application prospect in this rapidly developing field were also highlighted.

Renieramycin-type alkaloids from marine-derived organisms: Synthetic chemistry, biological activity and structural modification.

Marine natural products are known for their diverse chemical structures and extensive bioactivities. Renieramycins, the member of tetrahydroisoquinoline family of marine natural products, arouse interests because of their strong antitumor activities and similar structures to the first marine antitumor agent ecteinascidin-743, approved by the European Union. According to the literatures, researches on the pharmacological activities of renieramycins mainly focus on their antitumor activities. In addition, by structural modification, derivatives of renieramycins show stronger antiproliferative activity and less accidental necrosis activity on cells. Nevertheless, the difficulties in extraction and separation hinder their further development. Hence, the synthetic chemistry work of renieramycins plays a key role in their further development. In this review, currently reported researches on the synthetic chemistry, pharmacological activities and structural modification of renieramycins are summarized, which will benefit future drug development and innovation.

Polarization Beam Splitter Based on Si3N4/SiO2 Horizontal Slot Waveguides for On-Chip High-Power Applications.

In this paper, we propose an Si3N4/SiO2 horizontal-slot-waveguide-based polarization beam splitter (PBS) with low nonlinearity for on-chip high-power systems. The coupling length ratio between the quasi-TE and quasi-TM modes (LTE/LTM) was optimized to 2 for an efficient polarization splitting. For the single-slot design, the coupling length of the PBS was 281.5 µm, while the extinction ratios (ER) of the quasi-TM and quasi-TE modes were 23.9 dB and 20.8 dB, respectively. Compared to PBS based on the Si3N4 strip waveguide, the coupling length became 22.6% shorter. The proposed PBSs also had a relatively good fabrication tolerance for an ER of >20 dB. For the multi-slot design, the coupling length of the PBS was 290.3 µm, while the corresponding ER of the two polarizations were 24.0 dB and 21.0 dB, respectively. Furthermore, we investigated the tradeoff between the ER and coupling length for the optimized PBSs with single slot or multiple slots.