Efficient high-power orthogonal dual-slab Yb:KGd(WO4)2 laser oscillator with a TEM00 mode.

We demonstrated a TEM00 mode orthogonal dual-slab Yb:KG(WO4)2(Yb:KGW) laser oscillator with high average power. Polarization anisotropy of thermal lenses was investigated and alleviating the astigmatism based on orthogonal dual-slab. In addition, the laser polarization was directly controlled by adjusting the net gain of the two crystals. The maximum output power was highly enhanced compared with single crystal due to effective thermal distribution. For an absorbed pump power of 52.4 W, this oscillator delivered an average power of 26.5 W, corresponding to an optical-to-optical conversion efficiency of 50.6%. Meanwhile, the ellipticity of the output laser was optimized to 0.940. Nearly diffraction-limited beam quality was measured to be M x2 = 1.19 and M y2=1.18.

417†W, 2.38†mJ Innoslab amplifier compressible to a high pulse quality of 406†fs.

We demonstrate a 417 W, 175 kHz Innoslab chirped pulse amplification laser compressible to short and clean 406 fs pulse duration. A spectral bandwidth (full width at half maximum, FWHM) of ∼3 nm was maintained at full pump power, and the pulses exhibited good pulse quality in a wide tunable pulse energy range from 1.7 mJ to a maximum of 2.38 mJ. At the maximum output power, the compressed pulses were nearly pedestal free. The comprehensive effects of residual high-order dispersion from the front end, the gain shaping effects of the amplifier, and the slight mismatch of third-order dispersion (TOD) between the stretcher (CFBG) and the gating compressor, along with the small nonlinear phase shift accumulated in the amplifier, could have facilitated the high pulse quality. To the best of our knowledge, this is the shortest pulse duration from the Innoslab amplifiers at hundreds of watts average power in the millijoule energy regime.

Dual-slab Yb:KGd(WO4)2 regenerative amplifier for spectral shaping and high-power output.

A high-power regenerative amplifier (RA) based on dual-slab Yb:KGd(WO4)2 (Yb:KGW) was demonstrated, which provided a maximum average power of 33.7 W at a repetition rate of 75-200 kHz before compression with a central wavelength of 1039 nm, corresponding to an optical-to-optical conversion efficiency of 51.4%. To the best of our knowledge, this is the highest average power from the Yb:KGW solid-state RA. The compressed pulse duration of 205 fs was realized under the maximum output power. By adjusting the gain of the crystals, respectively, the spectral shaping can be achieved. A combination spectrum with root-mean-square (RMS) bandwidth of 4.5 nm was generated with a central wavelength of 1035 nm at an output power of 20 W, the compressed pulse duration was 159 fs. Meanwhile, effective mitigation of thermal effects by dual-slab configuration guaranteed the nearly diffraction-limited beam quality: M x2 = 1.17 and M y2 = 1.20.

Third-generation sequencing and metabolome analysis reveal candidate genes and metabolites with altered levels in albino jackfruit seedlings.

BACKGROUND: Most plants rely on photosynthesis; therefore, albinism in plants with leaves that are white instead of green causes slow growth, dwarfing, and even death. Although albinism has been characterized in annual model plants, little is known about albino trees. Jackfruit (Artocarpus heterophyllus) is an important tropical fruit tree species. To gain insight into the mechanisms underlying the differential growth and development between albino jackfruit mutants and green seedlings, we analyzed root, stem, and leaf tissues by combining PacBio single-molecule real-time (SMRT) sequencing, high-throughput RNA-sequencing (RNA-seq), and metabolomic analysis. RESULTS: We identified 8,202 differentially expressed genes (DEGs), including 225 genes encoding transcription factors (TFs), from 82,572 full-length transcripts. We also identified 298 significantly changed metabolites (SCMs) in albino A. heterophyllus seedlings from a set of 692 metabolites in A. heterophyllus seedlings. Pathway analysis revealed that these DEGs were highly enriched in metabolic pathways such as 'photosynthesis', 'carbon fixation in photosynthetic organisms', 'glycolysis/gluconeogenesis', and 'TCA cycle'. Analysis of the metabolites revealed 76 SCMs associated with metabolic pathways in the albino mutants, including L-aspartic acid, citric acid, succinic acid, and fumaric acid. We selected 225 differentially expressed TF genes, 333 differentially expressed metabolic pathway genes, and 76 SCMs to construct two correlation networks. Analysis of the TF-DEG network suggested that basic helix-loop-helix (bHLH) and MYB-related TFs regulate the expression of genes involved in carbon fixation and energy metabolism to affect light responses or photomorphogenesis and normal growth. Further analysis of the DEG-SCM correlation network and the photosynthetic carbon fixation pathway suggested that NAD-ME2 (encoding a malic enzyme) and L-aspartic acid jointly inhibit carbon fixation in the albino mutants, resulting in reduced photosynthetic efficiency and inhibited plant growth. CONCLUSIONS: Our preliminarily screening identified candidate genes and metabolites specifically affected in albino A. heterophyllus seedlings, laying the foundation for further study of the regulatory mechanism of carbon fixation during photosynthesis and energy metabolism. In addition, our findings elucidate the way genes and metabolites respond in albino trees.

Nanosecond pulsed deep-red laser source by intracavity frequency-doubled crystalline Raman laser.

We demonstrated a deep-red laser source by intracavity frequency-doubled crystalline Raman laser for the first time, to the best of our knowledge. The actively Q-switched 1314 nm Nd:LiYF4 laser was first converted to the eye-safe Raman laser using a KGd(WO4)2 (KGW) crystal, which was subsequently frequency-doubled in a bismuth borate crystal. Benefiting from the KGW bi-axial properties, the deep-red laser source was able to lase separately at two different spectral lines at 730 and 745 nm. Under an optimal repetition rate of 4 kHz, the maximum average powers of 1.7 and 2.0 W were attained with good beam quality of M2≈1.7. The corresponding pulse durations were determined to be 3.0 and 2.8 ns with the peak powers up to approximately 140 and 180 kW, respectively.

High-peak-power narrowband eye-safe intracavity Raman laser.

We demonstrated a narrowband eye-safe intracavity Raman laser by incorporating a fused silica etalon into the fundamental resonator. The KGd(WO4)2 (KGW) Raman laser was pumped by an actively Q-switched Nd:YLF laser at 1314 nm. Thanks to the KGW bi-axial properties, two distinct eye-safe Raman lasers operating at 1461 and 1490 nm were obtained separately by rotation of the KGW crystal. At an optimized pulse repetition frequency of 4 kHz, the maximum average output powers of 3.6 and 4.0 W were achieved with the peak powers up to approximately 330 and 480 kW, respectively. The eye-safe Stokes emissions were narrow linewidth (∼0.05 nm FWHM; measurement limited) and near diffraction limited (M2 < 1.4). The powerful narrowband eye-safe Raman lasers are of interest for applications as diverse as laser range finding, scanning lidar and remote sensing.

High-peak-power eye-safe orthogonally-polarized dual-wavelength Nd:YLF/KGW Raman laser.

An actively Q-switched eye-safe orthogonally-polarized dual-wavelength intracavity Raman laser was demonstrated for the first time, to the best of our knowledge. The gain balanced dual-wavelength operation at 1314 and 1321 nm within an in-band pumped Nd:YLF laser was realized by slightly titling the cavity mirrors. Owing to the KGW bi-axial properties, two sets of simultaneous orthogonally-polarized dual-wavelength Raman lasers at 1470, 1490 nm and 1461, 1499 nm were achieved by simply rotating the KGW crystal for 90°, respectively. With an incident pump power of 30 W and an optimized pulse repetition frequency of 5 kHz, the maximum dual-wavelength Raman output powers of 2.6 and 2.4 W were obtained with the pulse widths of 5.8 and 6.3 ns, respectively, corresponding to the peak powers up to 89.7 and 76.5 kW.

Single-longitudinal-mode cascaded crystalline Raman laser at 1.7 µm.

A single-longitudinal-mode crystalline Raman laser in the 1.7 µm wave band was reported for the first time, to the best of our knowledge. The YVO4 Raman laser, which was intracavity-pumped by an actively Q-switched 1314 nm Nd:YLF laser, demonstrated the cascaded Stokes oscillation at 1715 nm. By inserting an etalon in the fundamental resonator, linewidth narrowing and power scaling of the second-Stokes laser were realized based on the spatial-hole-burning-free Raman gain. With an optimal pulse repetition frequency of 4 kHz, the maximum single-longitudinal-mode average output power of 1.8 W was acquired with the spectrum linewidth of ∼340MHz. Further increasing the incident pump power, the second-Stokes laser transitioned to multimode regime, and the maximum average output power reached 2.7 W with the peak power as high as ∼380kW.

Efficient high-power orthogonally-polarized dual-wavelength Nd:YLF laser at 1314 and 1321†nm.

We demonstrate an 806 nm laser diode end-pumped continuous-wave (CW) and actively Q-switched (AQS) orthogonally-polarized dual-wavelength Nd:YLF laser operating at 1314 and 1321 nm. Benefitting from the small difference of the stimulated emission cross sections at 1314 and 1321 nm in Nd:YLF crystal, the power equalized emissions at both wavelengths were achieved by simply titling the output coupler. A maximum CW output power of 9.2 W was obtained with the incident pump power of 32.5 W, giving an optical-to-optical conversion efficiency of approximately 28% and a slope efficiency of approximately 33%. Furthermore, active Q-switching was realized by inserting a Brewster-cut acousto optic modulator. For an incident pump power of 30 W, this oscillator delivered an average power of 6.5 W at a pulse repetition frequency (PRF) of 20 kHz, and a pulse energy of 2.6 mJ with a peak power of approximately 72 kW at a PRF of 1 kHz.

Frequency expansion of orthogonally polarized dual-wavelength laser by cascaded stimulated Raman scattering.

In this Letter, the frequency expansion of an orthogonally polarized dual-wavelength laser, based on the cascaded stimulated Raman scattering, was demonstrated for the first time, to the best of our knowledge. The dual-wavelength fundamental laser generated from two separate Nd:YLF crystals was free of gain competition. Integrating the benefit of the two different orthogonally polarized Raman gain peaks in the KGd(WO4)2 (KGW) crystal, two sets of first-Stokes orthogonally polarized dual-wavelength Raman lasers were first achieved by rotating the Raman crystal for 90°. Furthermore, by simply replacing the Raman output coupler, we attained another two sets of second-Stokes orthogonally polarized dual-wavelength Raman lasers via the cascaded Raman shift. At a pulse repetition frequency of 5 kHz, the maximum first-Stokes and second-Stokes dual-wavelength Raman output powers were 3.12 and 2.09 W, with the combined peak powers of approximately 240 and 290 kW, respectively.

Performance evaluation of continuous-wave mid-infrared wavelength conversion in silicon waveguides.

Continuous-wave (CW) mid-infrared (MIR) wavelength conversion is experimentally demonstrated using degenerate four-wave mixing (FWM) between two thulium-doped fiber (TDF) lasers in a silicon waveguide. One TDF laser is homemade with a high power and tunable wavelength, while the other one is a commercial product. The conversion efficiency is measured with respect to the pump power and the signal wavelength detuning. In the 2 µm MIR band, the measured 3 dB conversion bandwidth is 52 nm. It verifies the feasibility of FWM-based wavelength conversion based on silicon waveguides in future MIR optical communication systems.

All-optical wavelength conversion for telecommunication mode-division multiplexing signals in integrated silicon waveguides.

An all-optical wavelength conversion method for telecommunication-band mode-division multiplexing (MDM) signals is proposed in integrated silicon waveguides by using the four-wave mixing effect with a dual-mode pump. By engineering the dispersion profile of the integrated silicon waveguide, the phase-matching conditions are realized simultaneously for the TE01 mode and the TE11 mode of the MDM signal in the telecommunication band, and they can be converted to the idler modes simultaneously. In a 1.2-cm-long waveguide, the 3-dB conversion bandwidth reaches 58 nm with a conversion efficiency of -22.3 dB pumped by a 100-mW TE01 and 105-mW TE11 pump source.

Experimental demonstration of nonlinear enhancement in a graphene-deposited microfiber.

Nonlinear enhancement is experimentally demonstrated by depositing graphene scraps from graphene ethanol dispersion onto a tapered microfiber. The enhancement of the nonlinearity is verified by observing the four-wave mixing (FWM) effect in the homemade graphene-deposited microfiber (GDMF). When the incident pump power is 24.2 dBm, the FWM conversion efficiency in the GDMF reaches -57.1 dB. Compared to the bare microfiber with the same dimensions, the conversion efficiency is improved by more than 3 dB. Our fabricated GDMF provides a simple way to enhance the fiber nonlinearity, and it will be suitable for nonlinear applications such as wavelength conversion and other optical signal processing operations.

[Detection of Carbon Dioxide Concentration in Soil Profile Based on Nondispersive Infrared Spectroscopy Technique].

In order to explore the variation of CO2 concentration and soil respiration in soil profile, the nondispersive infrared (NDIR) spectroscopy technique was applied to continually estimate the soil CO2 concentration in different soil layers (the humus horizon, A-, B-, C-horizon) in situ. The main instrument used in this experiment was silicon-based nondispersive infrared sensor, which could work in severe environment. We collected the Measurement value by NDIR spectroscopy technique throughout 2013. The values of soil carbon flux in different soil layers were calculated based on the model of gradient method and calibrated by measuring with an automated soil CO2 efflux system (LI-8100). The results showed that: a vertical gradient for the carbon dioxide concentration in soil profile was found, and the concentration was highest in the deepest soil horizon. Moreover, A linear correlation between the soil CO2 effluxes was calculated based on model and measurement, and the model prediction correlation coefficient was 0.9069, 0.7185, 0.8382, and 0.9030 in the H-, A-, B-, and C-horizon, respectively. The roots of mean square error (RMSE) were 0.2067, 0.1041, 0.0156, and 0.0096 in the H-, A-, B-, and C-horizon, respectively. These results suggest that the gradient method based on the NDIR spectroscopy technique can be successfully used to measure soil CO2 efflux in different soil layers, which reveal that diffusion and convection transport CO2 between the soil layers. It is a promising sensor for detecting CO2 concentration in soil profile, providing the basic data for calculating the global carbon in soil profile.

Differential Water Conservation Capacity in Broadleaved and Mixed Forest Restoration in Latosol Soil-Eroded Region, Hainan Province, China.

The water conservation capacity of the litter and soil layers of forest ecosystems improves the function of forest ecosystems in conserving soil and water. Plantation restoration plays a key role in preventing soil erosion. In order to evaluate the water conservation capacity of plantation restoration in Latosol soil-eroded region, we analyzed the litter thickness and mass, water absorption process, water holding recovery process, and soil water holding capacity of five restoration types (Hevea brasiliensis, Acacia mangium, Eucalyptus robusta, Acacia-Eucalyptus, and Acacia-Hevea) in the Mahuangling Watershed, Hainan province. The results showed that the thickness of the litter ranged from approximately 3.42 ± 0.24 to 4.73 ± 0.81 cm, and the litter mass ranged from 5.04 ± 1.52 t·ha-1 to 13.16 ± 1.76 t·ha-1, with higher litter mass in the SL layer than in the UL layer. The litter mass of A. mangium was higher than that of H. brasiliensis, E. robusta, Acacia-Eucalyptus, and Acacia-Hevea, which was 3.16 ± 1.76 t·ha-1. A. mangium forest was significantly higher than other plantation restoration types in terms of the maximum water retention capacity (Qmax) and the effective water retention capacity (Qeff). The soil bulk weight ranged from approximately 1.52 ± 0.09 to 1.59 ± 0.08 g·cm-3, and porosity ranged from 31.77 ± 4.72 to 35.62 ± 3.02%, both of which increased with the depth of the soil layer. The water holding capacity of 0-60 cm soil varied from approximately 12.94 ± 7.91 to 45.02 ± 31.79 t·ha-1, with A. mangium having the best soil permeability and the strongest soil water holding capacity. The entropy weight method was used to conduct a comprehensive evaluation, and the results showed that the water conservation capacity of the soil layer was 1.26 times higher than that of the litter layer, in which the water conservation capacity of A. mangium was the strongest, with a comprehensive evaluation value of 0.2854, which effectively intercepted rainfall and reduced surface runoff. Hence, we suggest that the planting of A. mangium should be considered in future ecological restoration projects of the erosion area of Mahuangling in order to improve the function of conserving soil and water in a restoration forest ecosystem.

LS-NTP: Unifying long- and short-range spatial correlations for near-surface temperature prediction.

The near-surface temperature prediction (NTP) is an important spatial-temporal forecast problem, which can be used to prevent temperature crises. Most of the previous approaches fail to explicitly model the long- and short-range spatial correlations simultaneously, which is critical to making an accurate temperature prediction. In this study, both long- and short-range spatial correlations are captured to fill this gap by a novel convolution operator named Long- and Short-range Convolution (LS-Conv). The proposed LS-Conv operator includes three key components, namely, Node-based Spatial Attention (NSA), Long-range Adaptive Graph Constructor (LAGC), and Long- and Short-range Integrator (LSI). To capture long-range spatial correlations, NSA and LAGC are proposed to evaluate node importance aiming at auto-constructing long-range spatial correlations, which is named as Long-range aware Graph Convolution Network (LR-GCN). After that, the Short-range aware Convolution Neural Network (SR-CNN) accounts for the short-range spatial correlations. Finally, LSI is proposed to capture both long- and short-range spatial correlations by intra-unifying LR-GCN and SR-CNN. Upon the proposed LS-Conv operator, a new model called Long- and Short-range for NPT (LS-NTP) is developed. Extensive experiments are conducted on two real-world datasets and the results demonstrate that the proposed method outperforms state-of-the-art techniques. The source code is available on GitHub:https://github.com/xuguangning1218/LS_NTP.

Pathogenesis and treatment of neuropsychiatric systemic lupus erythematosus: A review.

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease with a complex pathogenesis. Neuropsychiatric systemic lupus erythematosus (NPSLE) is a serious complication of SLE that involves the nervous system and produces neurological or psychiatric symptoms. After decades of research, it is now believed that the diverse clinical manifestations of NPSLE are associated with intricate mechanisms, and that genetic factors, blood-brain barrier dysfunction, vascular lesions, multiple autoimmune antibodies, cytokines, and neuronal cell death may all contribute to the development of NPSLE. The complexity and diversity of NPSLE manifestations and the clinical overlap with other related neurological or psychiatric disorders make its accurate diagnosis difficult and time-consuming. Therefore, in this review, we describe the known pathogenesis and potential causative factors of NPSLE and briefly outline its treatment that may help in the diagnosis and treatment of NPSLE.

Follicular Fluid-Derived Exosomal MicroRNA-18b-5p Regulates PTEN-Mediated PI3K/Akt/mTOR Signaling Pathway to Inhibit Polycystic Ovary Syndrome Development.

Small RNA sequences in follicular fluid (FF)-derived exosomes (extracellular vesicles contain proteins, DNA, and RNA) vitally function in the development of polycystic ovary syndrome (PCOS). It has been identified that microRNA (miR)-18b-5p is one of miRs that differ between control and PCOS women that passed the false discovery rate, and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is an important modifier of biological functions of ovarian granulosa cells (GCs) in PCOS. However, whether miR-18b-5p could functionally mediate the progression of PCOS via PTEN was not clarified completely, which was the issue we wanted to solve in our research. FF-derived exosomes were isolated using an extraction kit. KGN cells were co-cultured with miR-18b-5p-modified exosomes or transfected with a PTEN-related vector. After treatment, cell proliferation and apoptosis were observed. A rat model of PCOS was established by letrozole and then injected with miR-18b-5p-modified exosomes. Then, serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and estradiol (E2) levels in PCOS rats were measured. miR-18b-5p, PTEN, and phosphatidylinositol 3 kinases/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway-related genes were tested. In PCOS patients, miR-18b-5p was downregulated, and PTEN was highly expressed in FF and GCs. PTEN knockdown increased KGN cell proliferation and limited apoptosis. FF-derived exosomes stimulated proliferation and suppressed apoptosis of KGN cells; decreased FSH, LH, and testosterone; and increased E2 in PCOS rats. Upregulating miR-18b-5p further enhanced the inhibitory effects of exosomes on suppressing the progression of PCOS. miR-18b-5p targeted PTEN and could activate PI3K/Akt/mTOR pathway. miR-18b-5p produced by FF-derived exosomes reduces PTEN expression and promotes the activation of the PI3K/Akt/mTOR signaling pathway to improve PCOS. Based on that, circulating miR-18b-5p levels can contribute to the progression of PCOS complications.

RNA Sequencing Reveals Phenylpropanoid Biosynthesis Genes and Transcription Factors for Hevea brasiliensis Reaction Wood Formation.

Given the importance of wood in many industrial applications, much research has focused on wood formation, especially lignin biosynthesis. However, the mechanisms governing the regulation of lignin biosynthesis in the rubber tree (Hevea brasiliensis) remain to be elucidated. Here, we gained insight into the mechanisms of rubber tree lignin biosynthesis using reaction wood (wood with abnormal tissue structure induced by gravity or artificial mechanical treatment) as an experimental model. We performed transcriptome analysis of rubber tree mature xylem from tension wood (TW), opposite wood (OW), and normal wood (NW) using RNA sequencing (RNA-seq). A total of 214, 1,280, and 32 differentially expressed genes (DEGs) were identified in TW vs. NW, OW vs. NW, and TW vs. OW, respectively. GO and KEGG enrichment analysis of DEGs from different comparison groups showed that zeatin biosynthesis, plant hormone signal transduction, phenylpropanoid biosynthesis, and plant-pathogen interaction pathways may play important roles in reaction wood formation. Sixteen transcripts involved in phenylpropanoid biosynthesis and 129 transcripts encoding transcription factors (TFs) were used to construct a TF-gene regulatory network for rubber tree lignin biosynthesis. Among them, MYB, C2H2, and NAC TFs could regulate all the DEGs involved in phenylpropanoid biosynthesis. Overall, this study identified candidate genes and TFs likely involved in phenylpropanoid biosynthesis and provides novel insights into the mechanisms regulating rubber tree lignin biosynthesis.

(Epi)genetic variants of the sarcomere-desmosome are associated with premature utero-contraction in spontaneous preterm labor.

Spontaneous preterm birth is a syndrome with clinical and genetic heterogeneity. Few studies have focused on the genetic and epigenetic defects and pathogenic mechanisms associated with premature uterine contraction in spontaneous preterm birth. The objective of this study was to investigate the (epi)genetic variations associated with premature uterine contraction of spontaneous preterm birth. A systems biology approach with an integrated multiomic study was employed. Biobanked pregnancy tissues selected from a pregnancy cohort were subjected to genomic, transcriptomic, methylomic, and proteomic studies, with a focus on genetic loci/genes related to uterine muscle contraction, specifically, genes associated with sarcomeres and desmosomes. Thirteen single nucleotide variations and pathogenic variants were identified in the sarcomere gene, TTN, which encodes the protein Titin, from 146 women with spontaneous preterm labor. Differential expression profiles of five long non-coding RNAs were identified from loci that overlap with four sarcomeric genes. Longitudinally, the long non-coding RNA of gene TPM3 that encodes the protein tropomysin 3 was found to significantly regulate the mRNA of TPM3 in the placenta, compared to maternal blood. The majority of genome methylation profiles related to premature uterine contraction were also identified in the CpG promoters of sarcomeric genes/loci. Differential expression profiles of mRNAs associated with premature uterine contraction showed 22 genes associated with sarcomeres and three with desmosomes. The results demonstrated that premature uterine contraction was associated mainly with pathogenic variants of the TTN gene and with transcriptomic variations of sarcomeric premature uterine contraction genes. This association is likely regulated by epigenetic factors, including methylation and long non-coding RNAs.