fmr1 Mutation Alters the Early Development of Sensory Coding and Hunting and Social Behaviors in Larval Zebrafish.

Autism spectrum disorders (ASDs) are developmental in origin; however, little is known about how they affect the early development of behavior and sensory coding. The most common inherited form of autism is Fragile X syndrome (FXS), caused by a mutation in FMR1 Mutation of fmr1 in zebrafish causes anxiety-like behavior, hyperactivity, and hypersensitivity in auditory and visual processing. Here, we show that zebrafish fmr1-/- mutant larvae of either sex also display changes in hunting behavior, tectal coding, and social interaction. During hunting, they were less successful at catching prey and displayed altered behavioral sequences. In the tectum, representations of prey-like stimuli were more diffuse and had higher dimensionality. In a social behavioral assay, they spent more time observing a conspecific but responded more slowly to social cues. However, when given a choice of rearing environment fmr1-/- larvae preferred one with reduced visual stimulation, and rearing them in this environment reduced genotype-specific effects on tectal excitability. Together, these results shed new light on how fmr1-/- changes the early development of neural systems and behavior in a vertebrate.SIGNIFICANCE STATEMENT Autism spectrum disorders (ASDs) are caused by changes in early neural development. Animal models of ASDs offer the opportunity to study these developmental processes in greater detail than in humans. Here, we found that a zebrafish mutant for a gene which in humans causes one type of ASD showed early alterations in hunting behavior, social behavior, and how visual stimuli are represented in the brain. However, we also found that mutant fish preferred reduced visual stimulation, and rearing them in this environment reduced alterations in neural activity patterns. These results suggest interesting new directions for using zebrafish as a model to study the development of brain and behavior in ASDs, and how the impact of ASDs could potentially be reduced.

Improving Quantitative Analysis with Cross Instrument-Sparse Bayesian Learning (CI-SBL) Raman Spectroscopy Analysis Algorithm.

Qualitative and quantitative analysis of Raman spectroscopy is a widely used nondestructive analytical technique in many fields. It utilizes the Raman scattering effect of lasers to obtain molecular vibration information on samples. By comparison with the Raman spectra of standard substances, qualitative and quantitative analyses can be achieved on unknown samples. However, current Raman spectroscopy analysis algorithms still have many drawbacks. They struggled to handle quantitative analysis between different instruments. Their prediction accuracy for concentration is generally low, with poor robustness. Therefore, this study addresses these deficiencies by designing the cross instrument-sparse Bayesian learning (CI-SBL) Raman spectroscopy analysis algorithm. CI-SBL can facilitate spectroscopic analysis between different instruments through the cross instrument module. CI-SBL converts data from portable instruments into data from scientific instruments, with high similarity between the converted spectrum and the spectrum from the scientific instruments reaching 98.6%. The similarity between the raw portable instrument spectrum and the scientific instrument spectrum is often lower than 90%. The cross instrument effect of the CI-SBL is remarkable. Moreover, CI-SBL employs sparse Bayesian learning (SBL) as the core module for analysis. Through multiple iterations, the SBL algorithm effectively identified various components within mixtures. In experiments, CI-SBL can achieve a qualitative accuracy of 100% for the majority of binary and multicomponent mixtures. On the other hand, the previous Raman spectroscopy analysis algorithms predominantly yield a qualitative accuracy below 80% for the same data. Additionally, CI-SBL incorporates a quantitative module to calculate the concentration of each component within the mixed samples. In the experiment, the quantification error for all substances was below 3%, with the majority of the substances exhibiting an error of approximately 1%. These experimental results illustrate that CI-SBL significantly enhances the accuracy of qualitative judgment of mixture spectra and the prediction of mixture concentrations compared with previous Raman spectroscopy analysis algorithms. Furthermore, the cross instrument module of CI-SBL allows for a flexible handling of data acquired from different instruments.

Discovery of Unusual Ajmaline-Macroline Type Bisindole Alkaloids from Alstonia macrophylla by Building Blocks-Based Molecular Networking.

Three unusual ajmaline-macroline type bisindole alkaloids, alsmaphylines A-C, together with their postulated biogenetic precursors, were isolated from the stem barks and leaves of Alstonia macrophylla via the building blocks-based molecular network (BBMN) strategy. Alsmaphyline A represents a rare ajmaline-macroline type bisindole alkaloid with an S-shape polycyclic ring system. Alsmaphylines B and C are two novel ajmaline-macroline type bisindole alkaloids with N-1-C-21' linkages, and the former possesses an unconventional stacked conformation due to the presence of intramolecular noncovalent interactions. The chemical structures including absolute configurations of alsmaphylines A-C were established by comprehensive spectroscopic analyses, electronic circular dichroism (ECD) calculations, and single-crystal X-ray crystallography. In addition, a plausible biosynthetic pathway of these bisindole alkaloids as well as their ability to promote the protein synthesis on HT22 cells were discussed.

Effects of water replenishment on lake water quality and trophic status: An 11-year study in cold and arid regions.

Water replenishment is an important measure for maintaining and improving the aquatic environmental quality of lakes. The problems of water quality deterioration and water shortage can be alleviated by introducing water of higher quality. However, the mechanism of water replenishment in the improvement of the water quality and trophic status of lakes remains unclear. This study investigated water replenishment in Wuliangsuhai Lake (WLSHL) from 2011 to 2021 by collecting seasonal water samples and conducting laboratory analyses. Water replenishment was found to be capable of significantly improving lake water quality and alleviating eutrophication. It is worth noting that single long-term water replenishment measures have limitations in improving the water quality and trophic status. The whole process was divided into three stages according to the water quality and trophic status, namely the buffer period, decline period, and stable period. During the buffer period, the water quality and trophic status showed only slight improvement because of the small amount of water replenishment and the low proportion of higher-quality water from the Yellow River. In the decline period, with increasing water replenishment, the proportion of higher-quality water from the Yellow River gradually increased, leading to the most significant and stable degree of improvement. In the stable period, increases in the amount of water replenishment had little effect on improving the water quality and trophic status, which is attributable to the balance between internal pollutants (lake water-sediment), and the balance between internal-external pollutants (lake water-irrigation return flow + Yellow River water). On the premise of stable water quality, with eutrophication control as the management goal, the optimal water replenishment would be approximately 10.58 ×108 m3. Further necessary measures for solving aquatic environmental problems include the combination of sediment dredging, optimization of the water replenishment route, and implementation of quality management in water replenishment.

Objective sleep characteristics and continuous glucose monitoring profiles of type 2 diabetes patients in real-life settings.

AIM: To investigate the association between objective sleep parameters and glycaemic variability determined by continous glucose monitoring (CGM) among patients with type 2 diabetes, given the significant role of sleep in glycaemic control. METHODS: In this study, CGM was carried out in 28 patients with T2D (aged 62.3 ± 4.8 years, 57% women). Sleep characteristics were assessed by actigraphy within the CGM period. CGM-derived outcomes included glucose level, and percentages of time in range (TIR) and time above range (TAR) during the monitoring period. Associations between intraindividual night-to-night variations in sleep characteristics and overall CGM outcomes were analysed using linear regression. Associations between sleep characteristics during each night and time-matched CGM outcomes were analysed using linear mixed models. RESULTS: A total of 249 person-days of CGM, coupled with 221 nights of sleep characteristics, were documented. Greater standard deviation (SD) of objective sleep duration (minutes) between measurement nights was associated with higher glucose level (coefficient 0.018 mmol/L [95% confidence interval {CI} 0.004, 0.033], P = 0.017), smaller proportion of TIR (% in observation period; coefficient -0.20% [95% CI -0.36, -0.03], P = 0.023), and greater proportion of TAR (coefficient 0.22% [95% CI 0.06, 0.39], P = 0.011). Later sleep midpoint (minutes from midnight) was associated with greater SD of glucose during the same sleep period (coefficient 0.002 minutes [95% CI 0.0001, 0.003], P = 0.037), longer nocturnal sleep duration was associated with smaller coefficient of variation of glucose level in the upcoming day (-0.015% [95% CI -0.03, -0.001], P = 0.041). CONCLUSION: Objectively determined sleep duration and sleep midpoint, as well as their daily variability, are associated with CGM-derived glucose profiles in T2D patients.

Hovenianin A Alleviates Hepatic Fibrosis by Inhibiting the PI3K/AKT Pathway in TGF-ß1-Induced HSCs Based on Network Pharmacology and Transcriptomic Analysis.

Hepatic fibrosis is a global health problem, which currently has no FDA approved antifibrotic therapy yet. This study aimed to explore the mechanism of Hovenia genus in the treatment of hepatic fibrosis by an integrative strategy combining network pharmacology analysis, molecular docking, transcriptomics and experimental validation. The traditional Chinese medicine systems pharmacology (TCMSP) database and literatures were used to collect the components of Hovenia genus. Public databases including GeneCards, TTD, PharmGkb were used to acquire the putative targets. The GO and KEGG analysis were applied to explore the underlying mechanisms. Furthermore, The TGF-ß1 induced hepatic stellate cells (HSCs) model were performed to evaluate the anti-hepatic fibrosis activity of Hovenia genus. The RT-qPCR, Western blotting and flow cytometry experiments were used to validate the anti-hepatic fibrosis mechanisms of Hovenianin A. The KEGG analysis of network pharmacology and transcriptomics revealed that the core targets mainly enriched in PI3K-Akt signaling pathways. The cell screening results indicated flavonoids were the main active ingredients of Hovenia. Hovenianin A, a bioactive bisflavonol, was validated to promote the apoptosis of HSCs by inhibiting PI3K-Akt pathway. Molecular docking further corroborated the binding sites between Hovenianin A and AKT1. In summary, Hovenia may have therapeutic effects on liver fibrosis by modulating the PI3K-Akt apoptosis pathway. Our findings may facilitate the development of Hovenia genus, which could help to treat liver fibrosis in the future.

Long-Term Results and Risk Factors of Treatment for Post-Infarction Ventricular Septal Rupture: A Single-Center Experience.

BACKGROUND: Ventricular septal rupture (VSR) following myocardial infarction (MI) is a rare but lethal complication. We analyzed the long-term results and risk factors for survival in the treatment of VSR. METHODS: From January 2012 to December 2021, 115 consecutive patients with post-MI VSR were admitted to our hospital. Depending on different treatment methods patients were divided into following three groups: medical, transcatheter intervention, and surgical repair. During the study, relevant clinical data, operation-related conditions, and follow-up data were analyzed. The Kaplan-Meier method and log-rank test were used to determine the cumulative incidence of mortality. The independent risk factors for patient mortality were evaluated by multivariate logistic regression. RESULTS: The mean follow-up time was 43.4 ± 34.7 months. The overall in-hospital, 30-day, and long-term mortality rates were 24.3%, 38.3%, and 51.3%, respectively. In the medical group, the in-hospital and 30-day mortality rates were 46.7 % (21/45) and 82.2 % (37/45), respectively, with only three patients alive at follow-up. In the transcatheter intervention group, 30-day and long-term mortality rates were 12% and 28%, respectively. In the surgical repair group, 30-day and long-term mortality rates were 8.9% and 22.2%, respectively. Compared with the surgery-group patients, patients with transcatheter intervention had a longer time from VSR to intervention. Logistic regression analysis revealed that age, previous infarction, Killip class, serum creatinine, Troponin T, N-terminal pro-B-type natriuretic peptide, and medical strategy were risk factors for all-cause mortality. CONCLUSIONS: The 30-day and long-term outcomes of patients treated with surgical repair and transcatheter intervention were significantly better than medically treated patients.

Synthesis of nanoparticles via microfluidic devices and integrated applications.

In recent years, nanomaterials have attracted the research intervention of experts in the fields of catalysis, energy, biomedical testing, and biomedicine with their unrivaled optical, chemical, and biological properties. From basic metal and oxide nanoparticles to complex quantum dots and MOFs, the stable preparation of various nanomaterials has always been a struggle for researchers. Microfluidics, as a paradigm of microscale control, is a remarkable platform for online stable synthesis of nanomaterials with efficient mass and heat transfer in microreactors, flexible blending of reactants, and precise control of reaction conditions. We describe the process of microfluidic preparation of nanoparticles in the last 5 years in terms of microfluidic techniques and the methods of microfluidic manipulation of fluids. Then, the ability of microfluidics to prepare different nanomaterials, such as metals, oxides, quantum dots, and biopolymer nanoparticles, is presented. The effective synthesis of some nanomaterials with complex structures and the cases of nanomaterials prepared by microfluidics under extreme conditions (high temperature and pressure), the compatibility of microfluidics as a superior platform for the preparation of nanoparticles is demonstrated. Microfluidics has a potent integration capability to combine nanoparticle synthesis with real-time monitoring and online detection, which significantly improves the quality and production efficiency of nanoparticles, and also provides a high-quality ultra-clean platform for some bioassays.

Study on MICP dust suppression technology in open pit coal mine: Preparation and mechanism of microbial dust suppression material.

With the recent increases in energy demands, the dust hazards of coal mining caused by transportation, loading and unloading and other processes are becoming increasingly serious. To control dust in open pit coal mines more environmentally friendly and efficiently, and to promote the use and development of non-in situ high-yield urease microorganisms for dust suppression in coal mines, Bacillus pasteurii was selected for dust suppression experiments in this article. Additionally, the growth of microorganisms in the coal dust microenvironment was simulated, and the effect of microbial mineralization products on the calorific value of upper coal dust was further studied. Our findings indicated that Bacillus pasteurii induced dust suppression by forming a calcite precipitate with non-uniform particle size to coal dust cementation. Moreover, after a single spray, the wind erosion resistance efficiency was 84% when the wind speed was set at 10 m/s. The growth of microorganisms and urease activity in the coal dust leachate were largely equal to those in the control group, reaching a peak at approximately 24 h, that the maximum growth quantity of OD600 was about 1.5, and the maximum urease activity was 11 mmol·L-1·min-1. The difference between the peak heat release rate of mixed coal dust and pure coal was only 4.82 kW/m2, which would not affect the value of coal products. Non in-situ Bacillus pasteurii can be growth metabolized normally in the microenvironment of coal dust. Finally, the mechanism of coal dust suppression by mineralization of microbial bacterial solution to form calcium carbonate was described by a reaction equation, which is important for further application and development of microbial dust suppressants.

[A new dihydrochalcone from Humulus scandens].

To study the chemical constituents from the stems and leaves of Humulus scandens, this study isolated thirteen compounds by different chromatographic methods including silica gel column, ODS, Sephadex LH-20 and preparative HPLC. Based on comprehensive analysis, the chemical structures were elucidated and identified as citrunohin A(1), chrysosplenetin(2), casticin(3), neoechinulin A(4), ethyl 1H-indole-3-carboxylate(5), 3-hydroxyacetyl-indole(6),(1H-indol-3-yl) oxoacetamide(7), inonotusic acid(8), arteannuin B(9), xanthotoxol(10), α-tocopherol quinone(11), eicosanyl-trans-p-coumarate(12), and 9-oxo-(10E,12E)-octadecadienoic acid(13). Among them, compound 1 was a new dihydrochalcone, and the other compounds were obtained from H. scandens for the first time.

High-power Yb:CALGO regenerative amplifier and 30 fs output via multi-plate compression.

The pulse energy and average power are two long-sought parameters of femtosecond lasers. In the fields of nonlinear-optics and strong-field physics, they respectively play the role to unlock the various nonlinear processes and provide enough photon fluxes. In this paper, a high-energy and high-power Yb:CALGO regenerative amplifier with 120 fs pulse width is reported. This high-performance regenerative amplifier can work with high stability in a large tuning range of repetition rates. Varying the repetition rate from 3 to 180 kHz, the maximum output power of 36 W and the pulse energy up to 4.3 mJ, corresponding to a peak power of more than 20 GW are demonstrated. The output beam is near diffraction limited with M2 = 1.09 and 1.14 on the horizontal and vertical directions, respectively. In addition, multi-plate compression is employed to achieve 30 fs output with 23 W average power which is attractive for applications such as high-harmonic generation.

An efficient ensemble method for missing value imputation in microarray gene expression data.

BACKGROUND: The genomics data analysis has been widely used to study disease genes and drug targets. However, the existence of missing values in genomics datasets poses a significant problem, which severely hinders the use of genomics data. Current imputation methods based on a single learner often explores less known genomic data information for imputation and thus causes the imputation performance loss. RESULTS: In this study, multiple single imputation methods are combined into an imputation method by ensemble learning. In the ensemble method, the bootstrap sampling is applied for predictions of missing values by each component method, and these predictions are weighted and summed to produce the final prediction. The optimal weights are learned from known gene data in the sense of minimizing a cost function about the imputation error. And the expression of the optimal weights is derived in closed form. Additionally, the performance of the ensemble method is analytically investigated, in terms of the sum of squared regression errors. The proposed method is simulated on several typical genomic datasets and compared with the state-of-the-art imputation methods at different noise levels, sample sizes and data missing rates. Experimental results show that the proposed method achieves the improved imputation performance in terms of the imputation accuracy, robustness and generalization. CONCLUSION: The ensemble method possesses the superior imputation performance since it can make use of known data information more efficiently for missing data imputation by integrating diverse imputation methods and learning the integration weights in a data-driven way.

A novel pathogenicity determinant hijacks maize catalase 1 to enhance viral multiplication and infection.

Pathogens have evolved various strategies to overcome host immunity for successful infection. Maize chlorotic mottle virus (MCMV) can cause lethal necrosis in maize (Zea mays) when it coinfects with a virus in the Potyviridae family. However, the MCMV pathogenicity determinant remains largely unknown. Here we show that the P31 protein of MCMV is important for viral accumulation and essential for symptom development. Ectopic expression of P31 using foxtail mosaic virus or potato virus X induced necrosis in systemically infected maize or Nicotiana benthamiana leaves. Maize catalases (CATs) were shown to interact with P31 in yeast and in planta. P31 accumulation was elevated through its interaction with ZmCAT1. P31 attenuated the expression of salicylic acid (SA)-responsive pathogenesis-related (PR) genes by inhibiting catalase activity during MCMV infection. In addition, silencing of ZmCATs using a brome mosaic virus-based gene silencing vector facilitated MCMV RNA and coat protein accumulation. This study reveals an important role for MCMV P31 in counteracting host defence and inducing systemic chlorosis and necrosis. Our results have implications for understanding the mechanisms in defence and counter-defence during infection of plants by various pathogens.

Model-based decoupling of evoked and spontaneous neural activity in calcium imaging data.

The pattern of neural activity evoked by a stimulus can be substantially affected by ongoing spontaneous activity. Separating these two types of activity is particularly important for calcium imaging data given the slow temporal dynamics of calcium indicators. Here we present a statistical model that decouples stimulus-driven activity from low dimensional spontaneous activity in this case. The model identifies hidden factors giving rise to spontaneous activity while jointly estimating stimulus tuning properties that account for the confounding effects that these factors introduce. By applying our model to data from zebrafish optic tectum and mouse visual cortex, we obtain quantitative measurements of the extent that neurons in each case are driven by evoked activity, spontaneous activity, and their interaction. By not averaging away potentially important information encoded in spontaneous activity, this broadly applicable model brings new insight into population-level neural activity within single trials.

Altered brain-wide auditory networks in a zebrafish model of fragile X syndrome.

BACKGROUND: Loss or disrupted expression of the FMR1 gene causes fragile X syndrome (FXS), the most common monogenetic form of autism in humans. Although disruptions in sensory processing are core traits of FXS and autism, the neural underpinnings of these phenotypes are poorly understood. Using calcium imaging to record from the entire brain at cellular resolution, we investigated neuronal responses to visual and auditory stimuli in larval zebrafish, using fmr1 mutants to model FXS. The purpose of this study was to model the alterations of sensory networks, brain-wide and at cellular resolution, that underlie the sensory aspects of FXS and autism. RESULTS: Combining functional analyses with the neurons' anatomical positions, we found that fmr1-/- animals have normal responses to visual motion. However, there were several alterations in the auditory processing of fmr1-/- animals. Auditory responses were more plentiful in hindbrain structures and in the thalamus. The thalamus, torus semicircularis, and tegmentum had clusters of neurons that responded more strongly to auditory stimuli in fmr1-/- animals. Functional connectivity networks showed more inter-regional connectivity at lower sound intensities (a - 3 to - 6 dB shift) in fmr1-/- larvae compared to wild type. Finally, the decoding capacities of specific components of the ascending auditory pathway were altered: the octavolateralis nucleus within the hindbrain had significantly stronger decoding of auditory amplitude while the telencephalon had weaker decoding in fmr1-/- mutants. CONCLUSIONS: We demonstrated that fmr1-/- larvae are hypersensitive to sound, with a 3-6 dB shift in sensitivity, and identified four sub-cortical brain regions with more plentiful responses and/or greater response strengths to auditory stimuli. We also constructed an experimentally supported model of how auditory information may be processed brain-wide in fmr1-/- larvae. Our model suggests that the early ascending auditory pathway transmits more auditory information, with less filtering and modulation, in this model of FXS.

Wave-attenuation characteristics of combined-vegetation wave break forests for big rivers with large flood water level changes.

For large rivers with a compound cross section, the downstream channel has a very wide water surface during the flood season. A wide water surface, high water level, and larger wind speed will cause higher waves, increasing the threat of flooding to the dike. The design of a combined-vegetation wave break forest was put forward to achieve better wave attenuation effect. The main idea of this concept is to plant different types of vegetation at different locations in front of the dike. Three single-vegetation and four combined-vegetation forest schemes were tested under seven different water depth conditions. Both physical experiments and wave numerical simulations were carried out for each scheme to study the wave attenuation effect. The results showed that the wave attenuation effect of the single-vegetation wave break forest was significantly different under different water depth conditions, and the overall effect of the combined-vegetation of wave forest was better. Combined-vegetation wave break forests combine the advantages of different types of vegetation in different water levels, which makes it more economical and reasonable to plant by rivers with large water level variation. The proposed design ideas and methods could provide theoretical support for ecological revetment engineering of large rivers and insights for practical applications.

[A new alkaloid from Ervatamia hainanensis].

In order to study the alkaloids from branches and leaves of Ervatamia hainanensis, silica gel, ODS, Sephadex LH-20 and HPLC chromatography were used to obtain six alkaloids from the branches and leaves of E. hainanensis with use of. Based on the physicochemical properties and spectral data, their structures were identified as 10-hydroxydemethylhirsuteine(1), 3R-hydroxycoronaridine(2), 3-(2-oxopropyl)coronaridine(3), pandine(4), 16-epi-vobasine(5), and 16-epi-vobasinic acid(6). Among them, compound 1 was a new monoterpenoid indole alkaloid, and compounds 5 and 6 were obtained from this plant for the first time.

A Violaxanthin Deepoxidase Interacts with a Viral Suppressor of RNA Silencing to Inhibit Virus Amplification.

RNA silencing plays a critical role against viral infection. To counteract this antiviral silencing, viruses have evolved various RNA silencing suppressors. Meanwhile, plants have evolved counter-counter defense strategies against RNA silencing suppression (RSS). In this study, the violaxanthin deepoxidase protein of maize (Zea mays), ZmVDE, was shown to interact specifically with the helper component-proteinase (HC-Pro; a viral RNA silencing suppressor) of Sugarcane mosaic virus (SCMV) via its mature protein region by yeast two-hybrid assay, which was confirmed by coimmunoprecipitation in Nicotiana benthamiana cells. It was demonstrated that amino acids 101 to 460 in HC-Pro and the amino acid glutamine-292 in ZmVDE mature protein were essential for this interaction. The mRNA levels of ZmVDE were down-regulated 75% to 65% at an early stage of SCMV infection. Interestingly, ZmVDE, which normally localized in the chloroplasts and cytoplasm, could relocalize to HC-Pro-containing aggregate bodies in the presence of HC-Pro alone or SCMV infection. In addition, ZmVDE could attenuate the RSS activity of HC-Pro in a specific protein interaction-dependent manner. Subsequently, transient silencing of the ZmVDE gene facilitated SCMV RNA and coat protein accumulation. Taken together, our results suggest that ZmVDE interacts with SCMV HC-Pro and attenuates its RSS activity, contributing to decreased SCMV accumulation. This study demonstrates that a host factor can be involved in secondary defense responses against viral infection in monocot plants.

Flexible single-mode delivery of a high-power 2 µm pulsed laser using an antiresonant hollow-core fiber.

We demonstrate flexible single-mode transmission of a high average power 2 µm nanosecond pulse using antiresonant hollow-core fibers (AR-HCFs). 39.1 W average power is delivered using a coiled 1.7 m AR-HCF, which is designed for single-mode guidance and good higher-order mode suppression. The effect of bending on the fiber output power and beam profile is also investigated. The Gaussian-like output beam profile is maintained up to a 7.5 cm bending radius. This is the highest average power delivered by a flexible long HCF in this wavelength without the need for an enclosed controlled environment, to the best of our knowledge.

High-efficiency ultrafast Tm-doped fiber amplifier based on resonant pumping.

We demonstrated a high-efficiency ultrafast Tm-doped fiber amplifier based on a resonant pumping technique. A continuous-wave fiber laser at 1940 nm was employed as the pump laser. The slope efficiency of the resonantly pumped pulsed Tm-doped fiber amplifier reached 87% with respect to the launched pump power. The maximum average output power reached 40 W when the launched pump power was 53 W. The repetition rate and the pulse duration of the output pulses from a fiber amplifier were 248 MHz and 129 ps, respectively. The corresponding peak power was 1.25 kW, and the pulse energy was 161.3 nJ. To the best of our knowledge, this is the first demonstration of a resonant pumping enabled high-power high-efficiency ultrafast fiber laser operating at a 2 µm band.