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Effective wavelength extension is vital in the applications of high-power narrow-linewidth fiber lasers. In this work, we demonstrate a 5-kW power-level narrow-linewidth fiber amplifier at 1050â nm utilizing a homemade biconical-tapered Yb-doped fiber (BT-YDF). Up to â¼4.96â kW fiber laser is achieved with a 3â dB linewidth of â¼0.54â nm and a beam quality factor of Mx 2 = 1.46, My 2 = 1.6. The experimental comparisons reveal that BT-YDF has the advantages of improving a stimulated Raman scattering threshold and balancing transverse mode instability suppression in the fiber amplifier. This work could provide a good reference for extending the operating wavelength of high-power fiber amplifiers.
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In this paper, a hundred-watt-level near-diffraction-limited step-index Yb-doped fiber (YDF) laser near 980 nm is demonstrated firstly, to the best of our knowledge. By using the 11.7-W 979-nm single-mode seed light, the in-band amplified spontaneous emission (ASE) is well suppressed and the maximum output power of 101.5 W with the beam quality (M2 factor) of 1.285 was obtained. This work does not only propose an effective method for the suppression of in-band ASE, but also provides a cost-effective solution of hundred-Watt-level near-diffraction-limited fiber lasers near 980 nm.
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Requirements on the double-cladding Yb-doped fiber (DCYF) for power scaling of diffraction-limited fiber amplifiers are studied in this paper. By considering the limitations of thermal lens and transverse mode instability separately, it is found that the power scaling limit can be enlarged to more-than 100â kW and 80â kW, respectively, with the proper selection of pump and signal wavelengths. It is also found that the requirements on DCYF strongly depend on the wavelength and brightness of pump light. It is predicted that smaller-than 20-µm core diameter is required to achieve the 20-kW output power, as long as the 976-nm pump brightness can be high enough. The requirements on the inner-cladding diameter and cladding-to-core ratio of DCYF are also investigated.
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Patients with metastatic colorectal cancer often have poor outcomes, primarily due to hepatic metastasis. Colorectal cancer (CRC) cells have the ability to secrete cytokines and other molecules that can remodel the tumor microenvironment, facilitating the spread of cancer to the liver. Kupffer cells (KCs), which are macrophages in the liver, can be polarized to M2 type, thereby promoting the expression of adhesion molecules that aid in tumor metastasis. Our research has shown that huachanshu (with bufalin as the main active monomer) can effectively inhibit CRC metastasis. However, the underlying mechanism still needs to be thoroughly investigated. We have observed that highly metastatic CRC cells have a greater ability to induce M2-type polarization of Kupffer cells, leading to enhanced metastasis. Interestingly, we have found that inhibiting the expression of IL-6, which is highly expressed in the serum, can reverse this phenomenon. Notably, bufalin has been shown to attenuate the M2-type polarization of Kupffer cells induced by highly metastatic Colorectal cancer (mCRC) cells and down-regulate IL-6 expression, ultimately inhibiting tumor metastasis. In this project, our aim is to study how high mCRC cells induce M2-type polarization and how bufalin, via the SRC-3/IL-6 pathway, can inhibit CRC metastasis. This research will provide a theoretical foundation for understanding the anti-CRC effect of bufalin.
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Bufanólidos , Neoplasias del Colon , Interleucina-6 , Macrófagos del Hígado , Neoplasias Hepáticas , Macrófagos del Hígado/efectos de los fármacos , Macrófagos del Hígado/metabolismo , Bufanólidos/farmacología , Bufanólidos/uso terapéutico , Neoplasias Hepáticas/secundario , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Humanos , Animales , Interleucina-6/metabolismo , Interleucina-6/genética , Neoplasias del Colon/patología , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/metabolismo , Neoplasias del Colon/genética , Línea Celular Tumoral , Ratones , Antineoplásicos/farmacología , Microambiente Tumoral/efectos de los fármacos , Polaridad Celular/efectos de los fármacos , Metástasis de la NeoplasiaRESUMEN
Background: Bufalin, the main active ingredient of the traditional Chinese medicine huachansu, is used in the clinical treatment of colorectal cancer and has multiple effects, including the inhibition of migratory invasion, reversal of multi-drug resistance, induction of apoptosis and differentiation, and inhibition of angiogenesis. Methods: We collected relevant articles on bufalin from 2003 to 2022 using the Web Science platform, and analysed the information using VOSviewer, CiteSpace, and Microsoft Excel to categorise and summarise the publications over the past 20 years. Results: We collected 371 papers, with a steady increase in the number of articles published globally. China has the highest number of published articles, whereas Japan has the highest number of citations. Currently, there is considerable enthusiasm for investigating the anti-tumour mechanism of bufalin and optimising drug delivery systems for its administration. Conclusion: For the first time, we present a comprehensive overview of papers published worldwide on bufalin over the past two decades and the progress of its application in tumour therapy. We summarised the key authors, institutions, and countries that have contributed to the field and the potential of bufalin for the treatment of cancer. This will help other researchers obtain an overview of progress in the field, enhance collaboration and knowledge sharing, and promote future research on bufalin.
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Realizing stimulated Raman scattering (SRS) suppression is a key topic for high-power fiber lasers. Here, we report an effective and simple strategy for SRS suppression using chirped and tilted fiber Bragg gratings (CTFBGs) in high-power fiber oscillators while maintaining the compactness and stability of the system. The CTFBG is inserted on the side of a cavity mirror FBG without cutting the gain fiber. To improve power handling capability, the CTFBG and cavity mirror FBGs are inscribed by femtosecond (fs) lasers. The optimal SRS suppression effect can be realized when the CTFBG is inserted into the resonant cavity and on the side of the output coupler FBG. The SRS threshold is increased by approximately 11% with an SRS suppression ratio of nearly 14â dB. Moreover, the output power of the fiber oscillator is improved to 3.5â kW, which is the maximum power achieved in fiber oscillators with SRS suppression using CTFBGs, to the best of our knowledge. The temperature of the air-cooled CTFBG is 50.2 °C, which has the potential to handle higher power. This work provides new insights for suppressing SRS in fiber oscillators, promoting the application of CTFBGs in high-power lasers.
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We characterized high-power continuous-wave (CW) and pulsed mid-infrared (mid-IR) fiber amplifiers at a wavelength of 3.1â 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.
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Cadmium sulfide (CdS) is a photocatalyst widely used for efficient H2 production under visible light irradiation, due to its narrow bandgap and suitable conduction band position. However, the fast recombination of carriers results in their low utilization. In order to improve photocatalytic hydrogen production, it reports the successful introduction of metallic Cd and S vacancies on CdS nanorods (CdS NRs) by a facile in situ chemical reduction method, using a thermal treatment process. This procedure generates interfacial and polarization electric fields, that significantly improve the photocatalytic hydrogen production performance of CdS NRs in sodium sulfide and sodium sulfite aqueous solutions, under visible light irradiation (λ >420 nm). The introduction of these electric fields is believed to improve charge separation and facilitate faster interfacial charge migration, resulting in a significantly optimized catalyst, with a photocatalytic hydrogen evolution rate of up to 10.6 mmol-1 g-1 h-1 with apparent quantum efficiency (AQE) of 12.1% (420 nm), which is 8.5 times higher than that of CdS. This work provides a useful method to introduce metallic and S vacancies on metal sulfide photocatalysts to build local polarization and interfacial electric fields for high-performance photocatalytic H2 production.
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We present a robust chirped and tilted fiber Bragg grating (CTFBG) in a large-mode-area double-cladding fiber (LMA-DCF) written by a femtosecond (fs) laser. By implementing the fs-CTFBG into the output end of a high-power fiber laser for Raman filtering, a power handling capability of 4â kW is achieved with a Raman filtering ratio of â¼13â dB. To the best of our knowledge, this is the maximum handling power of a CTFBG for Raman filtering. The signal loss of the fs-CTFBG is 0.03â dB, which has little effect on the output laser beam quality. The air-cooled fs-CTFBG has a minimum temperature slope of 7.8°C/kW due to a self-annealing effect. This work proves the excellent performance of the fs-CTFBG, promoting the development of high-power CTFBGs.
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Tecnología de Fibra Óptica , Refractometría , Diseño de Equipo , Análisis de Falla de Equipo , Rayos LáserRESUMEN
Chirped and tilted fiber Bragg gratings (CTFBGs) are important all-fiber filtering components in high-power fiber lasers for stimulated Raman scattering (SRS) suppression. The fabrication of CTFBGs in large-mode-area double-cladding fibers (LMA-DCFs) by femtosecond (fs) laser is reported for the first time to the best of our knowledge. The chirped and tilted grating structure is obtained by scanning the fiber obliquely and moving the fs-laser beam relative to the chirped phase mask at the same time. By this method, the CTFBGs with different chirp rates, grating lengths, and tilted angles are fabricated, and the maximum rejection depth and bandwidth are â¼25â dB and â¼12â nm, respectively. To test the performance of the fabricated CTFBGs, one is inserted between the seed laser and the amplifier stage of a 2.7â kW fiber amplifier, and an SRS suppression ratio of â¼4â dB is achieved with no reduction in laser efficiency and degradation in beam quality. This work provides a highly fast and flexible method to fabricate large-core CTFBGs, which is of great significance to the development of high-power fiber laser systems.
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Photocatalysis provides a sustainable way for NOx elimination. However, efficient and safe photocatalytic removal of NOx remain a great challenge due to the limited light-harvesting ability and quick recombination of charge carriers. Herein, holey sulfur-doped g-C3N4 nanosheets (CNN-S) was reported by directly calcining a mixture of hydrolyzed dicyandiamide and thioacetamide. The specific surface area of the pristine g-C3N4 nanosheets (CNN-S0) is 3-4 times higher than bulk g-C3N4 (BCN), and the photocatalytic NO removal rate also increased from 17% (BCN) to 35% (CNN-S0). The effect of sulfur content on the photocatalytic performance was systematic studied, and CNN-S0.5 sample exhibits the highest NO removal rate (53%). The high photoreactivity of S-doped g-C3N4 nanosheets can be attributed to enhanced visible light absorption, increased specific surface area, and effective separation and transfer of photo-generated charges owing to the synergistic effect of the nanosheet structure and sulfur doping. In addition, density functional theory calculations show that the doping of S is also beneficial to the adsorption and activation of the reactants on CN.
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Luz , Azufre , Adsorción , TioacetamidaRESUMEN
Pyrolysis polygeneration has been proven to be effective in solid waste recycling, while cleaner production is hindered by nitrogen oxide emissions and waste oil utilization. In this study, waste bio-oil was proposed as additive for promoting urea-based selective non-catalytic reduction (SNCR) denitrification efficiency to establish bio-oil reusing process and the influence of waste bio-oil on promoting SNCR denitrification were investigated. Then the effects of temperature, bio-oil components and fly ash on SNCR denitrification characteristics were explored. The results illustrated that 5 wt% bio-oil additives would widen the optimum denitrification temperature window by 24.8 % (from 210.25 to 262.43 °C), reduce the reduction temperature by 62.11 °C (from 944.04 to 881.93 °C), and increase the denitrification efficiency by 21 %. Among the main components in waste bio-oil, acetic acid was more effective than phenol and furfural in promoting SNCR denitrification under 900 °C, a large amount of OH was produced to promote the reduction of NH3 and HNCO. In addition, the existence of fly ash could promote urea oxidation and reduce denitrification efficiency because of the catalytic effect of CaO and Fe2O3 on urea oxidation.
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Ceniza del Carbón , Urea , Desnitrificación , Óxidos de Nitrógeno , Calor , BiocombustiblesRESUMEN
Currently, chemoresistance is a major challenge that directly affects the prognosis of patients with colorectal cancer (CRC). In addition, hypoxia is associated with poor prognosis and therapeutic resistance in patients with cancer. Accumulating evidence has shown that αhederin has significant antitumour effects and that αhederin can inhibit hypoxiamediated drug resistance in CRC; however, the underlying mechanism remains unclear. In the present study, viability and proliferation assays were used to evaluate the effect of αhederin on the drug resistance of CRC cells under hypoxia. Sequencing analysis and apoptosis assays were used to determine the effect of αhederin on apoptosis under hypoxia. Western blot analysis and reverse transcriptionquantitative PCR were used to measure apoptosisrelated protein and mRNA expression levels. Furthermore, different mouse models were established to study the effect of αhederin on hypoxiamediated CRC drug resistance in vivo. In the present study, the high expression of Bcl2 in hypoxic CRC cells was revealed to be a key factor in their drug resistance, whereas αhederin inhibited the expression of Bcl2 by reducing AKT phosphorylation in vitro and in vivo, and promoted the apoptosis of CRC cells under hypoxia. By contrast, overexpression of AKT reversed the effect of αhederin on CRC cell apoptosis under hypoxia. Taken together, these results suggested that αhederin may overcome hypoxiamediated drug resistance in CRC by inhibiting the AKT/Bcl2 pathway. In the future, αhederin may be used as a novel adjuvant for reversing drug resistance in CRC.
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Neoplasias Colorrectales , Proteínas Proto-Oncogénicas c-akt , Animales , Ratones , Proteínas Proto-Oncogénicas c-akt/metabolismo , Neoplasias Colorrectales/patología , Proliferación Celular , Apoptosis , Resistencia a Antineoplásicos/genética , Hipoxia , Línea Celular Tumoral , Regulación Neoplásica de la Expresión GénicaRESUMEN
At present, recurrence and metastasis are still important factors that lead to a poor prognosis among colorectal cancer (CRC) patients. Cancer-associated fibroblasts (CAFs) can promote tumorigenesis and development. Bufalin is the main active monomer of the clinical drug cinobufacini, which exhibits antitumor activity in various cancers. But few research have investigated the effect of bufalin in inhibiting metastasis from the perspective of the tumor microenvironment. We first isolated CAFs from freshly resected colorectal cancer patient specimens and observed the effect of CAFs on CRC cell invasion through a series of experiments. We explored the effect of bufalin on the physiological activity of CRC mediated by CAFs through experiments. In our study, we found that CAFs could promote CRC cell activity through the STAT3 pathway. Bufalin reversed CAF-mediated CRC invasion and metastasis by inhibiting the STAT3 pathway. Overexpression of STAT3 attenuated the inhibitory function of bufalin on invasion and metastasis. Taken together, bufalin can reverse CAF-mediated colorectal cancer metastasis based on inhibiting the STAT3 signaling pathway.
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Fibroblastos Asociados al Cáncer , Neoplasias Colorrectales , Humanos , Fibroblastos Asociados al Cáncer/metabolismo , Fibroblastos Asociados al Cáncer/patología , Apoptosis , Transducción de Señal , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Línea Celular Tumoral , Proliferación Celular , Microambiente Tumoral/fisiología , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismoRESUMEN
We report here the first, to the best of our knowledge, demonstration of a mid-infrared (mid-IR) fiber gas amplifier based on acetylene-filled hollow-core fibers. A quasi-all-fiber structure fiber acetylene laser in a single-pass configuration is used as a seed. The injection of the seed removes the threshold and increases the laser efficiency, which are more pronounced at high pressure. In a 3.1-m HCF filled with 2.5 mbar of acetylene, the fiber gas amplifier shows a conversion efficiency (relative to the coupled pump power) of 22.2% at 3.1â µm, which is increased by 35% compared with that without the seed. Both the seed laser and the amplifier laser have good beam quality with M2 < 1.1. It is predictable that such a fiber gas amplifier can achieve a more efficient and higher power mid-IR output for other selected molecular species compared with the single-pass structure, which is beneficial to the development of high-power mid-IR fiber gas lasers.
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During task execution, the autonomous robots would likely pass through many narrow corridors along with mobile obstacles in dynamically complex environments. In this case, the off-line path planning algorithm is rather difficult to be directly implemented to acquire the available path in real-time. Hence, this article proposes a probabilistic roadmap algorithm based on the obstacle potential field sampling strategy to tackle the online path planning, called Obstacle Potential field-Probabilistic Roadmap Method (OP-PRM). The obstacle potential field is introduced to determine the obstacle area so as to construct the potential linked roadmap. Then the specific range around the obstacle boundary is justified as the target sampling area. Based on this obstacle localization, the effectiveness of the sampling points falling into the narrow corridors can be increased greatly for feasible roadmap construction. Furthermore, an incremental heuristic D* Lite algorithm is applied to search the shortest paths between the starting point and the target point on the roadmap. Simulation experiments demonstrate that the OP-PRM path planning algorithm can enable robots to search the optimal path fast from the starting point to the destination and effectively cross narrow corridors in complex dynamic environments.
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We report here the characteristics of a nanosecond high-power mid-infrared (mid-IR) light source based on an anti-resonant hollow-core fiber (AR-HCF) filled with acetylene gas. It is a single-pass configuration with 9.3-m HCFs, pumped by a modulated and amplified diode laser. A maximum average power of approximately 8 W (pulse energy of â¼0.8 µJ and peak power of â¼40 W) at 3.1 µm is achieved with a laser slope efficiency of â¼22.8% at 6 mbar of acetylene, which is, to the best of our knowledge, a record output power for such mid-IR HCF lasers. This work demonstrates the great potential of fiber gas lasers for high-power output in the mid-IR.
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INTRODUCTION: The aim of the study was to explore the mechanism by which minocycline protects the blood-brain barrier (BBB) in septic rats. METHODS: A sepsis rat model was generated in healthy, male Sprague-Dawley rats by cecal ligation and puncture (CLP). The rats were randomly divided into four groups and treated as follows: sham-operated plus normal saline (Sham + S group), CLP plus normal saline (CLP + S group), CLP plus minocycline pretreatment (CLP + M1 group), and CLP plus minocycline treatment (CLP + M2 group). Rats in the CLP + M1 group received 45 mg/kg minocycline by intraperitoneal injection every 12 h for 72 h. Rats in the Sham + S and CLP + S groups were injected with the same volume of normal saline every 12 h for 72 h. Rats in the CLP + M2 group were intraperitoneally injected with 45 mg/kg minocycline immediately after CLP and once every 12 h for 72 h. All rats were sacrificed at 72 h after operation. Tumor necrosis factor α and interleukin 6 levels, the expression of ionized calcium-binding adaptor molecule-1 (Iba-1), and the permeability of the BBB were measured. The expression of matrix metalloproteinases-9 (MMP-9) and the tight junction proteins zonula occludens-1 (ZO-1) and occludin was detected by Western blot. In addition, Evans blue (EB) staining, immunohistochemistry, and ELISA analysis were carried out. RESULTS: Minocycline pretreatment significantly inhibited microglial activation, decreased the sepsis-induced expression of MMP-9, increased the expression of ZO-1 and occludin, and improved the permeability of the BBB. Minocycline treatment failed to inhibit microglial activation, decrease the sepsis-induced expression of MMP-9, increase the expression of ZO-1 or occluding, or improve the permeability of the BBB. CONCLUSIONS: Minocycline pretreatment can effectively improve the altered permeability of the BBB caused by sepsis. The mechanism may be related to the inhibition of microglial activation and MMP-9 expression and increased expression of ZO-1 and occludin.
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Barrera Hematoencefálica , Sepsis , Animales , Masculino , Metaloproteinasa 9 de la Matriz/metabolismo , Minociclina/metabolismo , Minociclina/farmacología , Minociclina/uso terapéutico , Ocludina/metabolismo , Ratas , Ratas Sprague-Dawley , Solución Salina , Sepsis/metabolismoRESUMEN
PURPOSE: As rapidly dividing cells are usually the target of anticancer chemotherapy, it is inevitable that rapidly dividing normal cells become damaged, with myelosuppressive effects being a serious side effect of this therapy. Many recent studies have found that exosomal microRNAs (miRNAs) are related to the occurrence of some diseases. PATIENTS AND METHODS: Small RNA sequencing was used to investigate differential exosomal miRNAs with the same expression trend between groups after chemotherapy: MildA (before chemotherapy in patients with mild myelosuppression) and MildB (after chemotherapy in patients with mild myelosuppression); SevereA (before chemotherapy in patients with severe myelosuppression) and SevereB (after chemotherapy in patients with severe myelosuppression). A Venn diagram was generated to screen exosomal miRNAs related to chemotherapy. Small RNA sequencing was also used to investigate differentially expressed exosomal miRNAs among these groups, and exosomal miRNAs related to myelosuppression after chemotherapy was explored using a Venn diagram. RT-qPCR was applied to further verify the sequencing results. We performed target gene prediction and functional analysis for candidate exosomal miRNAs. RESULTS: Compared with that in the MildA or SevereA group, an increase in exosomal miR-122-5p was found in the MildB or SevereB group, and the expression level was lower in the SevereB group than in the MildB group. However, we found no notable difference in its expression level between the MildA and SevereA groups. Similar results were not obtained for the remaining miRNAs. RT-qPCR confirmed the screening results. Further analyses indicated that exosomal miR-122-5p targets CDK4 to inhibit the cell cycle. CONCLUSION: The expression level of exosomal miR-122-5p in the serum of patients with colorectal cancer correlates with the severity of myelosuppression caused by chemotherapy, and miR-122-5p targets CDK4 to inhibit cell cycle progression.
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In this Letter, to the best of our knowledge, the first kilowatt monolithic Yb-doped fiber laser operating near 980 nm is demonstrated. The fiber laser is achieved with the help of an all-fiber amplifier fabricated with a 105/250-µm core/cladding-diameter double-cladding Yb-doped fiber. With 11-W seed light, about 1.11-kW output power was obtained with 65.3% slope efficiency. The center wavelength was around 978 nm with a 10-dB bandwidth of about 0.6 nm. About 34-dB suppression of 1030-nm amplified spontaneous emission was realized, and the output beam quality (M2 factor) was about 16.2 at maximum output power. Better beam quality can be expected by optimizing the seed light and active fiber. This work can provide significant guidance for the study and designation of high-power fiber lasers operating near 980 nm and other three-level fiber sources.