2 W, 1.5†µm single-mode fiber methane Raman laser pumped by a Yb-doped fiber amplifier.

We report here, to the best of our knowledge, the first 1.5 µm methane-filled fiber Raman laser pumped by a fiber laser. Based on the narrow-linewidth pulsed Yb-doped fiber laser pump source and a 15 m hollow-core fiber filled with 2.5 bar methane, the maximum power of 2.06 W Stokes wave at 1543 nm is obtained. The output laser has a narrow linewidth of 2.3 GHz, and the pulse repetition frequency can be adjusted flexibly. The output shows excellent near-diffraction-limited beam quality with a M2 factor of ∼1.09. This work proves the advantage of the fiber laser pump source with modest peak power and flexible temporal characteristics in 1.5 µm fiber gas Raman laser emission, providing good guidance for generating pulsed fiber source with narrow linewidth and high beam quality.

High power mid-infrared fiber amplifier at 3.1†µm by acetylene-filled hollow-core fibers.

We characterized high-power continuous-wave (CW) and pulsed mid-infrared (mid-IR) fiber amplifiers at a wavelength of 3.1 µm in acetylene-filled hollow-core fibers (HCFs) with a homemade seed laser. A maximum CW power of 7.9 W was achieved in a 4.2-m HCF filled with 4-mbar acetylene, which was 11% higher than the power without the seed. The maximum average power of the pulsed laser was 8.6 W (pulse energy of 0.86 µJ) at 7-mbar acetylene pressure, a 16% increase over the power without the seed. To the best of our knowledge, backward characteristics are reported for the first time for fiber gas lasers, and the backward power accounted for less than 5% of the forward power. The optimum acetylene pressure and HCF length for the highest mid-IR output are discussed based on theoretical simulations. This study provides significant guidance for high-power mid-infrared (mid-IR) output in gas-filled HCFs.

Contribution of the Ultrasound Techniques in the Evaluation of Knee Joint Damage in the Case of Pigmented Villonodular Synovitis and Rheumatoid Arthritis.

OBJECTIVES: This is a prospective study to evaluate the clinical value of high-frequency ultrasound (HFUS), superb microvascular imaging (SMI), and contrast-enhanced ultrasound (CEUS) in differentiation of pigmented villonodular synovitis (PVNS) and highly active rheumatoid arthritis (RA). METHODS: Twenty PVNS patients and 24 active RA patients were selected to undergo HFUS, SMI, and CEUS examinations. The characteristics of HFUS, SMI, and CEUS in PVNS and RA were compared, and the differential diagnosis performances of HFUS, SMI, and CEUS in PVNS and RA were evaluated by receiver operating characteristic (ROC) analysis. RESULTS: There were statistically significant in joint effusion, synovial thickness, synovial morphology, synovial echo, synovial vessel shape, synovial enhanced direction, and enhanced pattern between PVNS and RA (P < .05). However, no statistically significant were found in bone erosion, synovial boundary, blood signal grading of synovium, synovial enhanced strength, and CEUS quantitative parameters (including PI, TTP, S, MTT, and AUC) (P > .05). The AUC of HFUS, SMI, and CEUS for differential diagnosis PVNS and RA were 0.832, 0.675, and 0.817, respectively. The AUC of HFUS + SMI, HFUS + CEUS, SMI + CEUS, HFUS + SMI + CEUS were 0.923, 0.940, 0.817, and 0.940, respectively. The AUC of HFUS + SMI and HFUS + CEUS was higher than that of each alone (P < .05). CONCLUSIONS: HFUS, SMI, and CEUS can be used as supplementary methods for diagnosis and differential diagnosis in PVNS and active RA. What is more, the combination of HFUS + SMI and HFUS + CEUS was suggested.

Fabrication of a Highly Efficient Wood-Based Solar Interfacial Evaporator with Self-Desalting and Sterilization Performance.

Solar interfacial evaporation based on wood-derived materials has been considered a promising strategy for desalination and wastewater purification. Herein, we adopted delignified wood (DW) as the water transport substrate and lignosulfonate (LS)-modified narrow-band gap semiconductor nickel disulfide (NiS2) as the light-absorbing agent (LS-NiS2) to fabricate a high-efficiency evaporator (LS-NiS2@DW). On the one hand, the high absorbance (>95%) within a broad wavelength range and excellent photothermal conversion efficiency of LS-NiS2 endow efficient solar energy utilization. On the other hand, the hydrophilicity of DW facilitates water activation, which results in a lower evaporation enthalpy of LS-NiS2@DW (1274.4 kJ kg-1) than that of pure water. By combining LS-NiS2 and DW, LS-NiS2@DW achieved an evaporation rate as high as 2.80 kg m-2 h-1 under one sun irradiation (1 kW m-2), and the evaporation efficiency reached 87.4%. Notably, LS-NiS2@DW exhibits a high evaporation rate (2.42-2.69 kg m-2 h-1) in simulated seawater for 24 h with no salt crystals formed on the surface. Moreover, LS-NiS2@DW shows high antibacterial activity with about 90% reduction in bacterial survival rate. This work could provide new perspectives for the design of a high-efficiency wood-based photothermal evaporator.

Investigation of the pump coupling efficiency of a side-pumping combiner based on tapered-fused method.

Side-pumping combiner is used for pumping double-clad fiber in various fiber laser schemes. However, its coupling efficiency and temperature characteristics suffer when pumped via a large numerical aperture (NA) pump light. We investigated the method of optimizing the coupling efficiency of a (2 + 1) ×1 combiner under a large NA pump light injection. After optimization of taper ratio and length of the pump fiber and fusion area between pump and signal fiber, the coupling efficiency increased and the temperature characteristic improved, which could be useful for fabrication of a side-pumping combiner for high-power fiber laser applications.

Family doctor contract services and health-related quality of life among patients with chronic diseases in rural China: what is the role of socioeconomic status?

PURPOSE: Few studies explored the relationship between the family doctor contract services (FDCS) and health-related quality of life (HRQOL) among patients with chronic diseases in rural China. This study aims to explore the relationship between the status of signing on FDCS and HRQOL among patients with chronic diseases and examine whether there are differences in the relationship between different socioeconomic status (SES). METHODS: A total of 1,210 respondents were included in this study. HRQOL was measured by EQ-5D-3L. The contracting status was divided into uncontracted and contracted. Tobit regression and Logistic regression were employed to explore the association between contracting status and HRQOL. The interaction terms were included to explore the differences in the association among different SES. RESULTS: Contracting with family doctors was associated with HRQOL (coefficient = 0.042; 95%CI 0.008 to 0.075). The association was different among different socioeconomic levels that the contracting status was only associated with HRQOL in sub-high-income (P < 0.01) and highly educated patients (P < 0.05). Compared with uncontracted patients, contracted patients reported higher ED-5D-3L utility value in the sub-high-income group (coefficient = 0.078; 95%CI 0.017 to 0.140) and high educational attainment (coefficient = 0.266; 95%CI 0.119 to 0.413). CONCLUSIONS: This study found a significant association between FDCS and HRQOL among chronic patients in rural Shandong, China. This relationship varied by income levels and educational attainment. The government should take efforts to formulate a variety of measures to encourage chronic patients to contract with family doctors, with special attention to people with low SES.

Do older people with cardiovascular-metabolic multimorbidity prefer to sign contracts for family doctor services? Evidence from a cross-sectional study in rural Shandong, China.

BACKGROUND: Family doctor policy is an important part of deepening healthcare reform in China. The study aimed to explore the association between cardiovascular-metabolic multimorbidity and the status of signing a contract for family doctor services among the older people in rural Shandong, China. METHODS: A cross-sectional study was conducted in 3 cities of Shandong province, China. A total of 1395 rural residents over 60 years of age were included in this study using a multistage stratified random sampling method. Covariates included demographic and socioeconomic characteristics, health-related characteristics, health service utilization, and awareness of family doctor contract services. The univariate and multivariate regression logistic analysis was used to analyze the data. RESULTS: There were 28.2% of the rural older people contracted for the family doctor contract services. The contract rate of seniors with cardiovascular-metabolic multimorbidity was statistically higher than those without cardiovascular-metabolic multimorbidity (OR = 1.67, 95%CI, 1.21-2.32) after controlling for confounding factors. In addition, occupation, physical activities, self-rated health status, distance from the village clinic, the awareness of family doctor contract services were found to be associated with the signing behavior among the rural older adults. CONCLUSION: This study demonstrated that the rural older people with cardiovascular-metabolic multimorbidity had a higher family doctor contract rate than those without cardiovascular-metabolic multimorbidity, and there was a gap between the current signing rate and the policy goal. To increase the rate of signing for family doctor contract services, the government should take joint efforts to expand the publicity and coverage, and give priority to meeting the healthcare demands of rural older adults with cardiovascular-metabolic multimorbidity.

Family characteristics associated with rural households' willingness to renew the family doctor contract services: a cross-sectional study in Shandong, China.

BACKGROUND: In China, some previous studies have investigated the signing rate and willingness of residents to sign the family doctor contract services (FDCS). Few studies have explored residents' willingness to renew the FDCS. This study is designed to understand the family characteristics difference towards rural households' willingness of maintaining the FDCS. METHODS: A total of 823 rural households were included in the analysis. A descriptive analysis was conducted to describe the sample characteristics. The binary logistic regression model was used to explore the family characteristics that influence the renewal willingness for FDCS among rural households in Shandong province, China. RESULTS: Our study found that about 95.5% rural households had willingness to maintain the FDCS in Shandong, China. Those households with catastrophic health expenditures (CHE) (OR = 0.328, 95%CI = 0.153-0.703), with highest level of education at graduate or above (OR = 0.303, 95%CI = 0.123-0.747) were less willing to maintain the FDCS. Those whose households have more than half of the labor force (OR = 0.403, 95%CI = 0.173-0.941) and those households living in economically higher condition were less willing to maintain the FDCS. CONCLUSIONS: This study demonstrates a significant association between family characteristics (CHE, highest education in households, proportion of the household labor force) and willingness to maintain FDCS among rural households in Shandong, China. Targeted policies should be made for rural residents of identified at-risk families.

Willingness of patients with chronic disease in rural China to contract with family doctors: implication for targeting characteristics.

BACKGROUND: Rural residents with chronic conditions have a stronger need for health services, which should make using family doctor contract services a priority. This study aimed to evaluate the rate of willingness among rural residents with chronic conditions to contract with family doctors and examine its determinants. METHODS: A cross-sectional study was conducted from May, 2018 to June, 2018 in Shandong Province in China. A total of 769 rural unsigned residents with chronic conditions were included in the analysis. Using the Andersen model as the theoretical framework, logistic regression models were chosen to analyse the factors associated with willingness to contract with family doctors. RESULTS: This study found that the rate of willingness to contract with family doctors among chronic patients in rural Shandong was 46.7%. A higher willingness was observed in those living a further distance from the village clinic (more than 600 m: OR = 1.85, 95%CI =1.17-2.93), having received publicity for family doctor contract services (OR = 1.71, 95% CI = 1.06-2.76), reporting need for utilizing a chronic disease management program (OR = 3.36, 95% CI = 2.20-5.23), and reporting need for higher medical insurance reimbursement (OR = 1.91, 95% CI = 1.28-2.83). CONCLUSIONS: The prevalence of contract willingness was relatively low among unsigned rural residents with chronic conditions in rural Shandong, China. The need factors were powerful factors affecting their willingness to contract with family doctors. The government should therefore strengthen targeted publicity and education to rural residents with chronic conditions and provide targeted healthcare services, such as chronic disease management programs and medical services with higher reimbursement rates, to promote their willingness to contract with family doctors.

Single-Fiber Laser Ablation in Treating Selected Metastatic Lymph Nodes of Papillary Thyroid Carcinoma and Benign Cold Thyroid Nodules-Preliminary Results.

BACKGROUND AND OBJECTIVES: To evaluate the feasibility and efficacy of single-fiber laser ablation (LA) under ultrasound guidance and appropriate ablation modes in the treatment of selected metastatic lymph nodes of papillary thyroid carcinoma (PTC) and benign cold thyroid nodules STUDY DESIGN/MATERIALS AND METHODS: A total of 18 patients (consisting of 8 patients with 18 metastatic lymph nodes of PTC and 10 patients with 10 benign cold thyroid nodules) each underwent one session of single-fiber LA under ultrasound guidance. On the basis of the sizes of the nodules, the ablation modes were chosen accordingly. The single-dot ablation mode was used in the nodules with three orthogonal diameters measuring no greater than 10 mm in diameter, with a dot, a level and an insertion. The double-dots overlapping ablation mode was used in the nodules with the largest diameters measuring greater than 10 mm (in which the nodules measured no more than 15 mm in diameter and with the other two perpendicular diameters measuring no greater than 10 mm in diameter) with two dots, a level and two insertions. The multiple levels and dots overlapping ablation mode was used in the nodules with the three orthogonal diameters all measuring larger than 10 mm, with multiple dots, levels and insertions. RESULTS: After 12 months of follow-up in the treated nodules of the metastatic lymph nodes of PTC and benign cold thyroid nodules, the mean baseline volumes decreased from 0.29 ± 0.12 to 0.03 ± 0.03 ml and 3.85 ± 0.64 to 1.1 ± 0.37 ml, respectively, and the mean volume reduction ratios (VRRs), which was calculated as {[(initial volume-final volume) × 100%]/initial volume}, were 90.3 ± 7.6% and 72 ± 5.8%, respectively. There were six ablative zones that completely disappeared, whereas the ablative zones that still existed presented as scar-like areas or small hyperechoic areas that were compatible with scar tissue among the 18 malignant nodules at the last follow-up. CONCLUSIONS: Single-fiber LA under ultrasound guidance, with the appropriate ablation modes, is feasible and effective for the treatment of selected metastatic lymph nodes of PTC and benign cold thyroid nodules. This study suggests that single-fiber LA may be applied to selected cases with appropriate ablation modes. Lasers Surg. Med. 2019 © 2019 Wiley Periodicals, Inc.

High-efficiency laser wavelength conversion in deuterium-filled hollow-core photonic crystal fiber by rotational stimulated Raman scattering.

We report here, to the best of our knowledge, for the first time high-efficiency laser wavelength conversion from 1.5 µm band to 1.7 µm band in deuterium-filled hollow-core photonic crystal fibers by rotational stimulated Raman scattering (SRS). Due to the special transmission properties of this low-loss hollow-core fiber, the ordinary dominant vibrational SRS is suppressed, permitting efficient conversion to the rotational stokes wave in a single-pass configuration pumped by a fiber amplified and modulated tunable 1.55 µm diode laser. Using proper pump pulse energy and gas pressure, the power conversion efficiencies over the whole output laser wavelength range from 1640 nm to 1674 nm are higher than 48%. And the maximum Raman conversion efficiency of 61.2% is achieved with 20 m fiber and 20 bar deuterium pressure pumped at 1540 nm, giving a maximum average power of about 0.8 W (pulse energy of 1.6 µJ). This work points to a new way for engineerable and compact fiber lasers operation at 1.7 µm band, which has significant applications in biological imaging, laser medical treatment, material processing and detecting.

Low-loss coupling from single-mode solid-core fibers to anti-resonant hollow-core fibers by fiber tapering technique.

We demonstrate here for the first time, to the best of our knowledge, an effective method to achieve low-loss light coupling from solid-core fibers to anti-resonant hollow-core fibers (AR-HCFs) by fiber tapering technique. We establish the coupling models by beam propagation method (BPM), and the simulation results show that the coupling efficiency can be optimized by choosing a proper waist diameter of the tapered solid-core fiber. Two types of AR-HCFs have been tested experimentally, and the maximum light coupling efficiency is ∼91.4% at 1.06 µm and ∼90.2% at 1.57 µm for the ice-cream AR-HCF, and ∼83.7% at 1.57 µm for the node-less AR-HCF. This work provides a feasible low-loss light coupling scheme for AR-HCFs, which is very useful for implementing all fiber systems.

Intelligent Sensor-Cloud in Fog Computer: A Novel Hierarchical Data Job Scheduling Strategy.

In the Fog Computer (FC), the process of data is prone to problems such as low data similarity and poor data tolerance. This paper proposes a hierarchical data job scheduling strategy Based on Intelligent Sensor-Cloud in Fog Computer (HDJS). HDJS dynamically adjusts the priority of the job to avoid job starvation and maximize the use of resources, uses the key frame to the resource occupied information, distributes the frame sequence to the unit, and then combines the intra frame distribution strategy to balance the load between the nodes. The experimental results show our proposed strategy may be possible to avoid the operation of hunger and resource fragmentation problems, make full use of the advantages of multi-core and multi-thread, improve system resource utilization, and shorten the execution time and response time.

0.83 W, single-pass, 1.54 µm gas Raman source generated in a CH4-filled hollow-core fiber operating at atmospheric pressure.

We report here the first watt-level efficient single-pass 1.54 µm fiber gas Raman source by methane-filled hollow-core fiber operating at atmospheric pressure. Pumped with a high-power MOPA (master oscillator power amplifier) structure Q-switched 1.06 µm pulsed solid-state laser, efficient 1.54 µm Stokes wave is generated in a single-pass configuration by vibrational stimulated Raman scattering of methane molecules. With an experimentally optimized fiber length of 3.2 m, we get a 1543.9 nm Stokes wave operating at atmospheric pressure with a record average power of ~0.83 W, which is about 12 times higher than the similar experiment previously reported, and the corresponding power conversion efficiency is about 45%. Operating at atmospheric pressure makes it more convenient in future applications.

High-power tunable mid-infrared fiber gas laser source by acetylene-filled hollow-core fibers.

High-power tunable pulsed and CW mid-infrared fiber gas laser sources in acetylene-filled hollow-core fibers, to the best of our knowledge, are demonstrated for the first time. By precisely tuning the wavelength of the pump source, an amplified tunable 1.5 µm diode laser, to match different absorption lines of acetylene, the laser output is step-tunable in the range of 3.09~3.21 µm with a maximum pulse average power of ~0.3 W (~0.6 µJ pulse energy) and a maximum CW power of ~0.77 W, making this system the first watt-level tunable fiber gas laser operating at mid-infrared range. The output spectral and power characteristics are systemically studied, and the explanations about the change of the ratio of the P over R branch emission lines with the pump power and the gas pressure are given, which is useful for the investigations of mid-infrared fiber gas lasers.

Efficient mid-infrared cascade Raman source in methane-filled hollow-core fibers operating at 2.8 µm.

We report here for the first time, to the best of our knowledge, a novel and efficient cascade Raman laser source operating at 2.8 µm by two stages of methane-filled hollow-core fibers (HCFs). In the first stage, a commercial 1064.6 nm laser is used as the pump source, and an efficient first-order Stokes wave of 1543.9 nm is obtained with a quantum conversion efficiency of ∼87% in 2 m ice-cream HCF filled with 2 bar methane gas. In the second stage, efficient 2.8 µm laser emission is also generated by the first-order stimulated Raman scattering of methane, while the pump source is the Stokes wave at 1543.9 nm. A maximum quantum conversion efficiency of ∼75% is obtained with 2.2 m node-less HCF filled with 11 bar methane gas, resulting in a record total quantum efficiency of ∼65%, which is 1.6 times the previous similar result. This work provides a significant efficient method to obtain a wide wavelength range of mid-infrared, even far-infrared fiber laser sources from conveniently available 1 µm band lasers with proper HCFs and different active gases.

Efficient high power, narrow linewidth 1.9 µm fiber hydrogen Raman amplifier.

We report here an efficient, high power, narrow linewidth 1.9 µm gas Raman amplifier by means of a hydrogen-filled hollow-core fiber. A 1.9 µm narrow linewidth continuous wave seed laser is coupled into the hollow-core fiber together with a high power pulsed 1064 nm MOPA laser through a shortpass dichroic mirror, and then amplified by stimulated Raman scattering of hydrogen. With 2 m fiber length and 4.5 bar gas pressure, the maximum average 1908 nm Stokes power of 570 mW is obtained, a record average power level for such experiments. The maximum peak power is about 50 kW, the linewidth is about 1 GHz, and the quantum efficiency is about 51%. This work has demonstrated the potential to get a high average power gas Raman laser in a hollow-core fiber, and it further provides the possibility to achieve a high average power 4 µm midinfrared fiber laser by cascaded gas stimulated Raman scattering.

Fabrication of chirped and tilted fiber Bragg gratings on large-mode-area doubled-cladding fibers by phase-mask technique.

We demonstrate here the inscription of chirped and tilted fiber Bragg gratings (CTFBGs), to the best of our knowledge, for the first time in hydrogen-loaded large-mode-area (LMA) double-cladding fibers using UV pulses and linearly chirped phase masks. High reflectivity wideband adjustable band-rejection filters are achieved in fibers like LMA-GDF-10/130-M and PS-GDF-20/400-M, with a wavelength coverage of more than 10 nm and suppression ratio around 20 dB. The spectrum and temperature properties are investigated. Experimental results indicate that CTFBGs could be used in double-cladding fiber systems with a smoothly varying attenuation spectrum and a low insertion loss, which is significant for further power scaling in a high-power fiber system.

Ultra-efficient Raman amplifier in methane-filled hollow-core fiber operating at 1.5 µm.

We report on what is, to the best of our knowledge, the first ultra-efficient 1.5 µm Raman amplifier in a methane-filled anti-resonance hollow-core fiber. A 1.5 µm single frequency seed laser is coupled into the hollow-core fiber together with a 1064 nm pulsed pump laser using a shortpass dichromic mirror, and then amplified by stimulated Raman scattering of methane. A maximum optical-to-optical conversion efficiency of 66.4% has been obtained, resulting in a record near quantum-limit efficiency of 96.3% in a 2 m long hollow-core fiber filled with only 2 bar methane gas. This kind of gas filled hollow-core Raman amplifier provides a potential method to obtain high efficiency mid-infrared laser sources with low threshold and narrow linewidth in various applications.

Rational Design of Antifouling Polymeric Nanocomposite for Sustainable Fluoride Removal from NOM-Rich Water.

The presence of natural organic matter (NOM) exerts adverse effects on adsorptive removal of various pollutants including fluoride from water. Herein, we designed a novel nanocomposite adsorbent for preferable and sustainable defluoridation from NOM-rich water. The nanocomposite (HZO@HCA) is obtained by encapsulating hydrous zirconium oxide nanoparticles (HZO NPs) inside hyper-cross-linked polystyrene anion exchanger (HCA) binding tertiary amine groups. Another commercially available nanocomposite HZO@D201, with the host of a cross-linked polystyrene anion exchanger (D201) binding ammonium groups, was involved for comparison. HZO@HCA features with abundant micropores instead of meso-/macropores of HZO@D201, resulting in the inaccessible sites for NOM due to the size exclusion. Also, the tertiary amine groups of HCA favor an efficient desorption of the slightly loaded NOM from HZO@HCA. As expected, Sigma-Aldrich humic acid even at 20 mg of DOC/L did not exert any observable effect on fluoride sequestration by HZO@HCA, whereas a significant inhibition was observed for HZO@D201. Cyclic adsorption runs further verified the superior reusability of HZO@HCA for defluoridation from NOM-rich water. In addition, the HZO@HCA column could generate ∼80 bed volume (BV) effluent from a synthetic fluoride-containing groundwater to meet the drinking water standard (<1.5 mg F/L), whereas HCA and HZO@D201 columns could only generate <5 and ∼40 BV effluents, respectively. This study is believed to shed new light on how to rationally design antifouling nanocomposites for water remediation.