Intense emission at 605†nm from Pr3+-doped fluorotellurite glass fibers.

Pr3+-doped fluorotellurite glass fibers (PDFTFs) were fabricated by using a rod-in-tube method. By using a 976/1400 nm dual-wavelength upconversion pump technique, an intense emission at 605 nm was obtained from a 6 cm long PDFTF, which was attributed to the transition 1D2 → 3H4 of Pr3+ ions. With an increase in power of the 1400 nm laser from ∼34 to ∼136 mW, the spectral bandwidth of the 605 nm emission decreased and the intensity of the 605 nm emission increased monotonically, indicating the generation of 605 nm amplified spontaneous emission (ASE). To the best of our knowledge, this is the first report of 605 nm ASE in PDFTFs. Our results showed that PDFTFs had the potential for constructing red fiber lasers and amplifiers.

Strip loaded waveguide amplifiers based on erbium-doped nanocomposites with 17†dB internal net gain.

We propose a strip loaded amplifier employing SU-8 as the loaded waveguide and nanoparticles (NPs)-polymethyl methacrylate (PMMA) as the cladding layer. By leveraging the undoped SU-8 loaded waveguide, the polymer waveguide amplifier accomplished remarkably low transmission losses, reaching as low as 1.8 dB/cm at 1530 nm. We prepared NPs-PMMA nanocomposite by utilizing NaLu0.1Y0.7F4: Er3+, Yb3+ @NaLuF4 core-shell nanoparticles, which exhibited a significantly enhanced lifetime of 6.15 ms. An internal net gain of up to 17.7 dB was achieved on a strip loaded waveguide with a length as short as 0.5 cm when the on-chip pump power was 77 mW. Signal enhancement (SE) was measured at different wavelengths, revealing that the strip loaded waveguide exhibited broadband SE ranging from 1510 nm to 1570 nm, covering the C-band. To the best of our knowledge, this work has achieved the highest gain results reported thus far on a polymer matrix and provides an efficient method for optical amplification in passive devices on silicon and Si3N4 platforms, leveraging the ease of integration of polymer materials with diverse photonic platforms.

Land degradation neutrality assessment and factors influencing it in China's arid and semiarid regions.

The ecosystems in China's arid and semiarid regions are notably fragile and experiencing dramatic land degradation. At the 12th Conference of the Parties (COP12) to the United Nations Convention to Combat Desertification (UNCCD) in October 2015, a definition for land degradation neutrality (LDN) was proposed and subsequently integrated into the Sustainable Development Goals (SDGs). Research on LDN has developed in terms of conceptual framework constructions, quantitative assessments, and empirical studies. However, LDN and its drivers must be clarified in China's arid and semiarid regions since some representative processes have yet to be fully considered in the assessment. Here, we develop an LDN indicator system specialised for the area, assess their LDN status, and determine the impacts of human activities and climate change on LDN. Our research aims to refine the LDN indicator system tailored for China's arid and semiarid regions by incorporating the trends of wind and water erosion. We also identify the influence of human activity and climate change on LDN, which provides insightful strategies for ecological restoration and sustainable development in drylands with climate-sensitive ecosystems. The results show that: (1) In 2020, more than half of areas of China's arid and semiarid regions achieved LDN, with more pronounced success in the southeastern areas compared to the central regions. (2) For LDN drivers, elevation shows negligible influence on LDN, whereas increased temperature promotes LDN achievement. Conversely, factors like vapour pressure deficit and v-direction wind speed hinder it. In conclusion, China's arid and semiarid regions achieved LDN, and the dominant factor that substantially influences LDN varies across geographical zones, with higher wind speeds and elevated GDP levels generally obstructing LDN in most areas.

Clinical outcomes of clip-assisted endoscopic cyanoacrylate injection versus conventional endoscopic cyanoacrylate injection in treating gastric varices with a gastrorenal shunt.

BACKGROUND AND STUDY AIMS: The optimal treatment for gastric varices (GVs) is a topic that remains definite for this study. This study compared the clinical outcomes of clip-assisted endoscopic cyanoacrylate injection (clip-ECI) to conventional endoscopic cyanoacrylate injection (con-ECI) for the treatment of GVs with a gastrorenal shunt. PATIENTS AND METHODS: Data were collected retrospectively in five medical centers from 2015 to 2020. The patients were treated with con-ECI (n = 126) or clip-ECI (n = 148). Clinical characteristics and procedural outcomes were compared. Patients were followed until death, liver transplantation or 6 months after the treatment. The primary outcome was rebleeding, and the secondary outcome was survival. RESULTS: There were no significant differences in age, sex, etiology, shunt diameter and Child-Pugh classification between the two groups. Fewer GVs obliteration sessions were required in the clip-ECI group than in the con-ECI group (p = 0.015). The cumulative 6-month rebleeding-free rates were 88.6% in the clip-ECI group and 73.7% in the con-ECI group (p = 0.002). The cumulative 6-month survival rates were 97.1% in the clip-ECI group and 94.8% in the con-ECI group (p = 0.378). CONCLUSIONS: Compared with con-ECI, clip-ECI appears more effective for the treatment of GVs with a gastrorenal shunt, which required less sessions and achieved a higher 6-month rebleeding-free rate.

Mood, hormone levels, metabolic and sleep across the menopausal transition in VCD-induced ICR mice.

AIMS: Menopausal transition is the transitional period before menopause in women, often accompanied by abnormal fluctuations in hormone levels that increase the risk of aging-related diseases. 4-vinylcyclohexene dioxide (VCD) is a chemical agent that induces gradual depletion of ovarian follicles, which can mimic the natural human process of transition from menopausal transition to post-menopause. Previous studies have shown that the onset of menopausal transition or menopause in VCD-injected mice is associated with a specific strain, even in inbred animals. Institute of Cancer Research (ICR) mice constitute general purpose outbred population, which has not been well-characterized in the VCD-induced model. Thus, the current study aimed to explore the characteristic features, including sleep, mood, and metabolism, of the model by examining the effect of timing of VCD injection in ICR mice to extend the applications of this model. MATERIALS AND METHODS: ICR mice were randomly divided into six groups: 20d VCD and 20d Control, 35d VCD and 35d Control, 52d VCD and 52d Control. VCD mice were intraperitoneally injected with VCD (160 mg/kg), while Control mice were injected intraperitoneally with sesame oil for 4 consecutive weeks, five times a week daily. A vaginal smear was used to observe the estrous cycle of the mice. On the 20th, 35th, and 52nd day after VCD or sesame oil injection, the ovarian morphology, the number of atretic cells, hormone levels, anxiety, depression-like behaviors, sleep phase, and energy metabolism were observed. KEY FINDINGS: The menopausal transition model was successfully replicated by injecting VCD into ICR mice. On the specific days after VCD treatment, the number of atretic follicles increased, the level of E2 decreased and FSH increased, the depressive- and anxiety-like behavior increased, the time of REM and NREM sleep time decreased, and energy metabolism was reduced. SIGNIFICANCE: These results suggested that the ICR mice model has human-like characteristics during the menopause transition. Moreover, the ICR model has a long menopausal transition duration.

Polymer/silica hybrid waveguide amplifier at 532 nm based on NaYF4:Er3+, Yb3+ nanocrystals.

An optical waveguide amplifier, which can solve the problem of optical attenuation in optical network transmission, is the key technology to solve optical chip integration and optical interconnection. Here, to the best of our knowledge, we propose a novel polymer/silica hybrid waveguide amplifier at 532 nm for the first time. The research is of great significance to the improvement of short distance communication and visible light communication system. The waveguide amplifier was designed as an embedded structure based on NaYF4:Er3+Yb3+ nanocrystals, which were synthesized by high-temperature thermal decomposition. When the input signal power was 0.1 mW, and the pump power was 300 mW, a relative gain of 4.3 dB was obtained on an 8 mm waveguide. This result is of great research significance to break the distance limit and make all-optical transmission a reality.

Research on a Fractal Dimension Calculation Method for a Nano-Polymer Microspheres Dispersed System.

Polymer microspheres (PMs) are a kind of self-similar volume expansion particle, and their fractal dimension varies with hydration swelling. However, there is no unique fractal dimension calculation method for their characteristics. A new model is established in this paper, which is particular to calculate the fractal dimension of PMs. We carried out swelling hydration experiments and scanning electron microscope (SEM) experiments to verify the new model. The new model and the box-counting model were used to calculate the fractal dimensions of PMs based on the hydration experiment results. Then, a comparison of the calculation results of the two methods was used to verify the validity of the model. Finally, according to the new model calculation results, the fractal dimension characteristics of PMs were analyzed. The research results indicate that the new model successfully correlates the cumulative probability of the PMs dispersed system with the fractal dimension and makes fractal dimension calculation of PMs more accurate and convenient. Based on the experiment results, the new model was used to calculate the fractal dimension of PMs and the box-counting model, and its findings were all 2.638 at initial state hydration and 2.739 and 2.741 at hydration time as of day 1. This result verifies the correctness of the new model. According to the hydration swelling experiments and the new model calculation results, the fractal dimension is linear correlated to the average particle size of PMs and the standard deviation average particle size. This means the fractal dimension of PMs represents the space occupancy ability and space occupancy effectiveness.

Research on the Impact of the Built Environment on the Characteristics of Metropolis Rail Transit School Commuting-Take Wuhan as an Example.

The long-distance commute to school caused by urban sprawl and the car-oriented urban construction model are key factors leading to primary/middle school students being picked up by their parents in cars. Encouraging those students to take rail transit can reduce their dependence on cars. This paper uses a stepwise regression based on rail-transit swipe data to explore the influence of the built environment on rail-transit commuting characteristics in Wuhan, and uses a geographically weighted regression (GWR) model to analyze the spatial heterogeneity of significant influencing variables. The study found that: (1) 60% of students are one-way commuters; (2) 88.6% of students travel less than 10 km; (3) the floor area ratio, bus station density and whether the station is a transfer station have an obvious positive effect on the flow of commuters; (4) whether the station is a departure station has a positive effect on the commuting distance, but the mixed degree of land use and road density have a negative effect on the commuting distance. This research can assist cities in formulating built environment optimization measures and related policies to improve school-age children's use of rail transit. This is important in the development of child-friendly cities.