Enhanced Frequency Conversion in Parity-Time Symmetry Line.

Non-Hermitian degeneracies reveal intriguing and nontrivial behaviors in open physical systems. Examples like parity-time (PT) symmetry breaking, topological encircling chirality, and enhanced sensing near an exceptional point (EP) are often associated with the abrupt nature of the phase transition around these degeneracies. Here we experimentally observe a cavity-enhanced second-harmonic frequency (SHG) conversion on a PT symmetry line, i.e., a set consisting of open-ended isofrequency or isoloss lines, both terminated at EPs on the Riemann surface in parameter space. The enhancement factor can reach as high as 300, depending on the crossing point whether in the symmetry or the broken phase of the PT line. Moreover, such enhancement of SHG enables sensitive distance sensing with a nanometer resolution. Our works may pave the way for practical applications in sensing, frequency conversion, and coherent wave control.

Low-Threshold Anti-Stokes Raman Microlaser on Thin-Film Lithium Niobate Chip.

Raman microlasers form on-chip versatile light sources by optical pumping, enabling numerical applications ranging from telecommunications to biological detection. Stimulated Raman scattering (SRS) lasing has been demonstrated in optical microresonators, leveraging high Q factors and small mode volume to generate downconverted photons based on the interaction of light with the Stokes vibrational mode. Unlike redshifted SRS, stimulated anti-Stokes Raman scattering (SARS) further involves the interplay between the pump photon and the SRS photon to generate an upconverted photon, depending on a highly efficient SRS signal as an essential prerequisite. Therefore, achieving SARS in microresonators is challenging due to the low lasing efficiencies of integrated Raman lasers caused by intrinsically low Raman gain. In this work, high-Q whispering gallery microresonators were fabricated by femtosecond laser photolithography assisted chemo-mechanical etching on thin-film lithium niobate (TFLN), which is a strong Raman-gain photonic platform. The high Q factor reached 4.42 × 106, which dramatically increased the circulating light intensity within a small volume. And a strong Stokes vibrational frequency of 264 cm-1 of lithium niobate was selectively excited, leading to a highly efficient SRS lasing signal with a conversion efficiency of 40.6%. And the threshold for SRS was only 0.33 mW, which is about half the best record previously reported on a TFLN platform. The combination of high Q factors, a small cavity size of 120 µm, and the excitation of a strong Raman mode allowed the formation of SARS lasing with only a 0.46 mW pump threshold.

Measuring and analyzing the information entropy value of key Audit matters (KAMs) disclosure at the system and reporting scale.

Drawing upon information entropy theory, this study deduces a measurement formula for the information entropy for key audit matters (KAMs) disclosure, considering both system scale and audit report scale. The information entropy of an audit report within a specific system is calculated as the weighted average logarithm value of the continuous product of KAM disclosure frequencies. Subsequently, a systematic calculation of KAM disclosure information entropy is conducted using 14,837 financial statement audit reports from listed companies traded on the Shanghai and Shenzhen Stock Exchanges, covering the FY 2017-20 period. The findings indicate that: (1) The information entropy of KAM disclosure has decreased from 2017 to 2020, while the homogenization degree of KAM disclosure has increased. (2) The information entropy and evenness of KAM disclosure on the main board are significantly higher than those of the ChiNext and the STAR Market. (3) The transportation, storage and postal services, manufacturing, finance, power supply, heating, gas and water supply industries exhibit the highest overall information entropy of KAM disclosure, indicating good quality. (4) The information entropy and evenness of KAM disclosure are higher for the big 4 accounting firms compared to domestic accounting firms and big 8 accounting firms. (5) The KAMs disclosed when the Certified Public Accountant (CPA) provides unqualified opinions, emphasizing that matter paragraphs possess higher information value, and are more disorderly and balanced. The measurement method and related results of information entropy offer reference and comparative value for future research on the quality of KAMs disclosure.

High-efficiency second harmonic generation in a micro-resonator on dual-layered lithium niobate.

High-quality micro-resonators on thin-film lithium niobate (TFLN) have emerged as an ideal platform for on-chip nonlinear optical applications due to their strong light confinement and excellent natural nonlinear optical properties. Here, we present high-efficiency second-harmonic generation (SHG) in micro-resonators on a TFLN based on the modal phase matching and natural quasi-phase matching. By optimizing the phase-matching conditions through thermal tuning, we demonstrate an on-chip SHG efficiency of 149,000%/W in the low power regime. Furthermore, we achieve an absolute conversion efficiency of 10.3% with a 0.3 mW pump power. Our work paves the way toward future efficient on-chip frequency conversion of classical and quantum light without the need for poling of the LN films.

Host plant-induced changes in metabolism and osmotic regulation gene expression in Diaphorina citri adults.

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a worldwide citrus pest. It transmits the pathogen Candidatus Liberibacter spp. of Huanglongbing (HLB), causing severe economic losses to the citrus industry. Severalgenera of plants in the Rutaceae family are the hosts of D. citri. However, the impact of these hosts on the metabolism and osmotic regulation gene expression of the pest remains unexplored. In this study, the contents of total sugars, sucrose, fructose, and glucose in young shoots, old leaves, and young leaves of 'Shatangju' mandarin and Murraya exotica were analyzed. Metabolomic analysis found that sucrose and trehalose were more abundant in the gut samples of D. citri adults fed on M. exotica when compared to what's in 'Shatangju' mandarin. A total of six aquaporin genes were identified in D. citri through the genome and transcriptome data. Subsequently, the expression patterns of these genes were investigated with respect to their developmental stage and tissue specificity. Additionally, the expression levels of osmotic regulation and trehalose metabolism genes in adults fed on different plants were evaluated. Our results provide useful information on the transfer of sugar between plants and D. citri. Our results preliminary revealed the sugar metabolism regulation mechanism in D. citri adults.

Characterization and transcriptomic analyses of the toxicity induced by toosendanin in Spodoptera frugipreda.

The fall armyworm, Spodoptera frugiperda, is a destructive agricultural pest that seriously threatens global food security. Insecticide resistance of this pest has gradually formed in recent years due to improper usage, and alternative methods are badly needed. Toosendanin (TSN) is a botanical compound with broad-spectrum insecticidal activities against many pests. However, the effects of TSN on S. frugiperda are still unclear. In this study, the growth inhibition phenomenon, including weight loss and prolonged developmental duration, in the larvae with TSN exposure was clearly observed. Compared to the control group, a total of 450 and 3314 differentially expressed genes (DEGs) were identified by RNA-Seq in the larvae groups treated with 10 and 20 mg/kg TSN, respectively. Furthermore, the DEGs involved in the juvenile hormone and ecdysone signal pathways and downstream processes, including detoxifying enzyme genes, chitin synthesis and metabolism genes, and cuticular protein genes, were found. Our findings suggest that TSN regulates the expression of key genes in juvenile hormone and ecdysone signal pathways and a series of downstream processes to alter the hormone balance and cuticle formation and eventually inhibit larval growth, which laid the foundation for the molecular toxicological mechanism research of TSN on S. frugiperda larvae.

Ultra-high Q lithium niobate microring monolithically fabricated by photolithography assisted chemo-mechanical etching.

As one of the element photonic structures, the state-of-the-art thin-film lithium niobate (TFLN) microrings reach an intrinsic quality (Q) factor higher than 107. However, it is difficult to maintain such high-Q factors when monolithically integrated with bus waveguides. Here, a relatively narrow gap of an ultra-high Q monolithically integrated microring is achieved with 3.8 µm, and a high temperature annealing is carried out to improve the loaded (intrinsic) Q factor with 4.29 × 106 (4.04 × 107), leading to an ultra-low propagation loss of less than 1 dB/m, which is approximately 3 times better than the best values previously reported in ion-slicing TFLN platform.

The effects of carvacrol on development and gene expression profiles in Spodoptera frugiperda.

The fall armyworm, Spodoptera frugiperda, is a highly polyphagous agricultural pest that is widely distributed around the world and causes severe crop yield loss. Carvacrol showed adverse effects on many pests, such as larval death and growth inhibition. While the effects of carvacrol on S. frugiperda larvae are not yet known. In this study, the effects of carvacrol on S. frugiperda, including larval growth inhibition and mortality induction, were observed. The detoxification and digestive enzyme activities of larvae with 1.0 and 2.0 g/kg carvacrol treatments were analyzed. Carvacrol boosted the enzyme activities of carboxylesterase (CarE) and glutathione S-transferase (GST) while decreasing the activities of α-amylase (AMS), lipase (LIP), and trypsin. A total of 3422 differentially expressed genes were identified in the larvae treated with 2.0 g/kg carvacrol, of which the DEGs involved in xenobiotic detoxification, food digestion, and insecticidal targets were further examined. These results suggest that carvacrol could regulate growth and development by affecting the process of food digestion, and exert its toxicity on the larvae through interaction with a variety of insecticidal targets. While the altered expressions of detoxification enzymes might be related to the detoxification and metabolism of carvacrol. Our findings offer a theoretical foundation for the use of carvacrol for S. frugiperda control in the field.

Characterization of the physiological, histopathological, and gene expression alterations in Spodoptera frugiperda larval midguts affected by toosendanin exposure.

The fall armyworm, Spodoptera frugiperda, is a polyphagous pest worldwide and feeds on many grain and cash crops, which threatens the safety of agriculture and forestry production. Toosendanin (TSN) is a commercial insecticidal active ingredient used to manage various pests in the field and showed adverse effects against S. frugiperda, while the effects of TSN on the larval midguts are not yet known. In this study, the effects of 10 and 20 mg/kg TSN exposures on the larval midguts were analyzed. The structural changes of the larval midgut induced by TSN treatments were also determined by hematoxylin-eosin staining. Besides, TSN treatments also changed the enzyme activities of three digestive enzymes (α-amylase, lipase, and trypsin) and two detoxification enzymes (CarE and GST). A total of 2868 differentially expressed genes (DEGs) were identified by RNA-Seq in the larval midguts with 20 mg/kg TSN treatment, and the DEGs responsible for food digestion and detoxification were further examined. Our findings revealed the preliminary modes of action of TSN on the larval midguts of S. frugiperda, which provide a preliminary rationale for controlling S. frugiperda with TSN in the field.

Erbium-ytterbium codoped thin-film lithium niobate integrated waveguide amplifier with a 27†dB internal net gain.

A photonic integrated waveguide amplifier fabricated on erbium-ytterbium (Er-Yb) codoped thin-film lithium niobate (TFLN) has been investigated in this work. A small-signal internal net gain of 27 dB is achieved at a signal wavelength of 1532 nm in the fabricated Er-Yb TFLN waveguide amplifier pumped by a diode laser at ≈980 nm. Experimental characterizations reveal the suitability of waveguide fabrication by the photolithography-assisted chemo-mechanical etching (PLACE) technique and also the gain in an Yb-sensitized-Er material. The demonstrated high-gain chip-scale TFLN amplifier is promising for interfacing with established lithium niobate integrated devices, greatly extending the spectrum of TFLN photonic applications.

The comparison of gut gene expression and bacterial community in Diaphorina citri (Hemiptera: Liviidae) adults fed on Murraya exotica and 'Shatangju' mandarin (Citrus reticulate cv. Shatangju).

BACKGROUND: Diaphorina citri Kuwayama is an important citrus pest. It serves as the vector for the transmission of Candidatus Liberibacter asiaticus (CLas), which induced a destructive disease, Huanglongbing, and caused huge economic losses. During the interaction between insects and plants, insects have evolved a series of mechanisms to adapt to various host plants. Murraya exotica and 'Shatangju' mandarin (Citrus reticulate cv. Shatangju) are the Rutaceae species from different genera that have been discovered as suitable hosts for D. citri adults. While the adaptation mechanism of this pest to these two host plants is unclear. RESULTS: In this study, RNA-seq and 16 S rDNA amplification sequencing were performed on the gut of D. citri adults reared on M. exotica and 'Shatangju' mandarin. RNA-seq results showed that a total of 964 differentially expressed genes were found in different gut groups with two host plant treatments. The impacted genes include those that encode ribosomal proteins, cathepsins, and mitochondrial respiratory chain complexes. According to 16 S rDNA sequencing, the compositions of the gut bacterial communities were altered by different treatments. The α and ß diversity analyses confirmed that the host plant changes influenced the gut microbial diversity. The functional classification analysis by Tax4Fun revealed that 27 KEGG pathways, mostly those related to metabolism, including those for nucleotide metabolism, energy metabolism, metabolism of cofactors and vitamins, amino acid metabolism, carbohydrate metabolism, xenbiotics biodegradation and metabolism, lipid metabolism, and biosynthesis of other secondary metabolites, were significantly altered. CONCLUSION: Our preliminary findings shed light on the connection between D. citri and host plants by showing that host plants alter the gene expression profiles and bacterial community composition of D. citri adults.

Does the disclosure of key audit matters improve the audit quality for sustainable development: Empirical evidence from China.

In this paper, taking the 14837 annual audit reports of 4159 listed companies in Shanghai and Shenzhen Stock Exchanges from 2017 to 2020 as samples, and taking the information entropy value of KAM disclosures and the type of audit opinion as the agent indexes of the explanatory variable and the interpreted variable respectively, whether the disclosure of KAMs could improve audit quality had been empirically tested and analyzed. The results shown that: (1) The regression coefficient of information entropy value of KAMs disclosure was 0.1785, which shown a significant positive correlation, and was established at the level of 1% significance, that was to say, KAMs disclosure can improve audit quality. (2) The marginal effect coefficient was only 0.0081, which meant that there was some information redundancy in the KAMs disclosure and the enhancement effect on audit quality was weak. (3) In the robustness test, the interpreted variable was respectively replaced by audit cost (taking the natural logarithm of audit cost) and manipulated accrual profit (taking the absolute value of manipulated accrual profit), the regression coefficients of information entropy of KAMs were 0.0852 and 0.0017 respectively, which shown a significant positive correlation and were consistent with the results of the main regression test. (4) Further research shown that whether the industry in which the audited company was located and whether the audit institution was one of the international Big Four would affect the disclosure of KAMs, and then affect the audit quality in the same direction. The implementation effect of the new audit reporting standards was supported by these test evidences.

Controllable EIT-like mode splitting in a chiral microcavity.

Two coupled resonance modes can lead to exotic transmission spectra due to internal interference processes. Examples include electromagnetically induced transparency (EIT) in atoms and mode splitting in optics. The ability to control individual modes plays a crucial role in controlling such transmission spectra for practical applications. Here we experimentally demonstrate a controllable EIT-like mode splitting in a single microcavity using a double-port excitation. The mode splitting caused by internal coupling between two counter-propagating resonances can be effectively controlled by varying the power of the two inputs, as well as their relative phase. Moreover, the presence of asymmetric scattering in the microcavity leads to chiral behaviors in the mode splitting in the two propagating directions, manifesting itself in terms of a Fano-like resonance mode. These results may offer a compact platform for a tunable device in all-optical information processing.

Effects of azadirachtin on detoxification-related gene expression in the fat bodies of the fall armyworm, Spodoptera frugiperda.

The fall armyworm, Spodoptera frugiperda, has become a worldwide pest and threatens world food production. A previous study indicated that azadirachtin, the most effective botanical insecticide for S. frugiperda, inhibits larval growth of the insect. The effect of azadirachtin on the tissues of the larvae, however, remains to be determined. In this study, the effects of azadirachtin on the structure of fat bodies were analyzed. Comparative transcriptomic analysis was conducted between controls and samples treated with 0.1 µg/g azadirachtin for 7 days to explore potential relevant mechanisms. The expression of 5356 genes was significantly affected after azadirachtin treatment, with 3020 up-regulated and 2336 down-regulated. Among them, 137 encode detoxification enzymes, including 53 P450s, 20 GSTs, 27 CarEs, 16 UGTs, and 12 ABC transporters. Our results indicated that azadirachtin could destroy fat body structure and change the mRNA levels of detoxification-related genes. The up-regulated genes encoding detoxification enzymes might be related to detoxifying azadirachtin. Our results elucidate a preliminary mechanism of azadirachtin detoxification in the fat bodies of S. frugiperda larvae.

Integrated miRNA and transcriptome profiling to explore the molecular mechanism of Spodoptera frugiperda larval midgut in response to azadirachtin exposure.

As a destructive agricultural pest, Spodoptera frugiperda has spread worldwide in the past few years. Azadirachtin, an environmentally friendly and most promising compound, showed adverse effects, including mortality and growth inhibition, against S. frugiperda. While the effects of azadirachtin on the midgut of this pest remain to be determined. In this study, structural damage was observed in the larval midguts of S. frugiperda with azadirachtin exposure. RNA-seq on the larval midguts with different azadirachtin treatments was performed. Compared to the control group, a total of 3344 and 4759 differentially expressed genes (DEGs) were identified in the midguts with 0.1 and 0.5 µg/g azadirachtin exposure, respectively. Among them, the DEGs encoding detoxification enzymes/proteins, immune-related proteins, digestion and absorption-related proteins, and transcript factors were further analyzed. High-throughput sequencing was also used for the identification of differentially expressed microRNAs in different treatments. A total of 153 conserved miRNAs and 147 novel miRNAs were identified, of which 11 and 29 miRNAs were affected by 0.1 and 0.5 µg/g azadirachtin treatments, respectively. The integrated analysis found that 13 and 178 miRNA versus mRNA pairs were acquired in the samples with 0.1 and 0.5 µg/g azadirachtin treatments, respectively. The results of high-throughput sequencing were confirmed by real-time quantitative polymerase chain reaction (RT-qPCR). These results provide useful information for revealing the molecular mechanism of S. frugiperda larval midgut in response to azadirachtin.

Genome-wide identification, characterization and functional analysis of the chitianse and chitinase-like gene family in Diaphorina citri.

BACKGROUND: Insect chitinases play vital roles in postembryonic development, especially during the molting process, and are potential targets for the RNA interference (RNAi)-based insecticidal strategy. Systematic functional analyses of chitinase genes have already been conducted on numerous insect pests, but similar analyses have not been carried out on Diaphorina citri. RESULTS: Eleven chitinase/chitinase-like genes and one endo-ß-N-acetylglucosaminidase (ENGase) gene were identified in the Diaphorina citri genome using various bioinformatic tools. Transcriptomes of the integument and midgut from fifth-instar nymphs and freshly-emerged adults of Diaphorina citri were generated and sequenced. Potential functions of 12 chitinase/chitinase-like genes were examined during nymph-adult transitions. Four chitinase genes, including DcCht5, DcCht7, DcCht10-1 and DcCht10-2, were mainly expressed in the integument of fifth-instar nymphs. These four genes were also up-regulated significantly under 20-hydroxyecdysone (20E) treatments. RNAi-mediated knockdown of these four genes suggests that they are essential for nymph-adult transition. CONCLUSION: Our results demonstrated essential roles of the chitinase/chitinase-like genes during the nymph-adult transition in Diaphorina citri, which are potentially useful targets for controlling the Diaphorina citri pest. © 2022 Society of Chemical Industry.

Effects of camptothecin on histological structures and gene expression profiles of fat bodies in Spodoptera frugiperda.

Spodoptera frugiperda is a serious threat to global food production. Our previous study demonstrated that Camptothecin (CPT), a bioactive secondary metabolite from Camptotheca acuminata (Decne: Nyssaceae), exhibits adverse impact on the larval midgut of S. frugiperda and inhibits insect growth. However, effects of CPT on fat bodies of S. frugiperda larvae have not been examined yet. In the present study, we found that histological structures of fat bodies of S. frugiperda larvae were damaged in insects treated with CPT. Comparative transcriptomic analyses among different fat body samples from controls and insects treated with 1.0 and 5.0 µg/g CPT were performed. A total of 4212 and 5044 differentially expressed genes (DEGs) were identified in the samples treated with 1.0 and 5.0 µg/g CPT, respectively. Our data indicated that the pathways of detoxification, immune response, fatty acids, chitin, and hormone biosynthesis in fat bodies were affected by CPT treatments based on DEGs. These results provided a comprehensive view of the damage and gene expression changes in fat bodies of S. frugiperda after CPT exposure, which shall be useful to reveal the mechanism of CPT toxicity against S. frugiperda in future.

On-chip microdisk laser on Yb3+-doped thin-film lithium niobate.

We demonstrate an on-chip Yb3+-doped lithium niobate (LN) microdisk laser. The intrinsic quality factors of the fabricated Yb3+-doped LN microdisk resonator are measured up to 3.79×105 at a 976 nm wavelength and 1.1×106 at a 1514 nm wavelength. The multi-mode laser emissions are obtained in a band from 1020 to 1070 nm pumped by a 984 nm laser and with the low threshold of 103µW, resulting in a slope efficiency of 0.53% at room temperature. Furthermore, both the second-harmonic frequency of pump light and the sum frequency of the pump light and laser emissions are generated in the on-chip Yb3+-doped LN microdisk, benefiting from the strong χ(2) nonlinearity of LN. These microdisk lasers are expected to contribute to the high-density integration of a lithium niobate on insulator-based photonic chip.

Dendrobium officinale Polysaccharide Alleviates Intestinal Inflammation by Promoting Small Extracellular Vesicle Packaging of miR-433-3p.

Dendrobium officinale polysaccharide (DOP) attenuates inflammatory bowel disease (IBD), but its role in regulating cross-talk between intestinal epithelial cells (IEC) and macrophages against IBD is unclear. This study aimed to investigate DOP protective effects on the intestinal inflammatory response through regulation by miRNA in small extracellular vesicles (sEVs). Our results show that DOP interfered with the secretion of small extracellular vesicles (DIEs) by IEC, which reduced the levels of inflammatory mediators. Increased miR-433-3p expression in DIEs was identified as an important protector against intestinal inflammation. DOP regulated the loading of miR-433-3p by hnRNPA2B1 into the intestinal sEV to increase the abundance of miR-433-3p. DIEs delivered miR-433-3p to lipopolysaccharide-induced macrophages and targeted the MAPK8 gene, leading to inhibition of the MAPK signaling pathway and reduced production of inflammatory cytokines. One protective mechanism of DOP is mediated by intestinal sEV containing miR-433-3p, which is a potential therapeutic agent for the prevention of inflammatory factor accumulation from excessive intestinal macrophage activity and for restoring homeostasis in the intestinal microenvironment.

On-chip ultra-narrow-linewidth single-mode microlaser on lithium niobate on insulator.

We report an on-chip single-mode microlaser with a low threshold fabricated on erbium doped lithium-niobate-on-insulator (LNOI). The single-mode laser emission at 1550.5 nm wavelength is generated in a coupled microdisk via the inverse Vernier effect at room temperature, when pumping the resonator at 977.7 nm wavelength. A threshold pump power as low as 200 µW is demonstrated due to the high quality factor above 106. Moreover, the measured linewidth of the microlaser reaches 348 kHz without discounting the broadening caused by the utilization of optical amplifiers, which is, to our knowledge, the best result in LNOI microlasers. Such a single-mode microlaser lithographically fabricated on chip is in high demand by the photonics community.