Collision and dissociation of soliton molecules triggered by gain perturbation in passively mode-locked fiber laser.

Soliton molecule has the properties that similar to those of matter molecule, which brings great research value. The rich dynamics of soliton molecules depend on the complex interactions between pulses. As one of the important factors, gain dynamics has multi-dimensional effects on the interactions of soliton molecules. We here study the interaction process of soliton molecules under gain perturbation, and find the oscillation and collision behaviors of pulses within soliton molecules induced by gain perturbation, as well as the pulses recombination through interactions between soliton molecules. We believe that the energy change in the cavity and the energy transfer based on the continuous wave component play an important role in the evolution process of the dissociation of soliton molecules into three-pulses bunch and single pulse. These findings reveal the effects of gain on the motion of soliton molecules and provide a basis for exploring the control dynamics of soliton molecules.

Demonstration of 120 Gbit/s turbulence-resilient coherent optical communication employing cylindrical vector beam multiplexing.

Free space optical (FSO) communication has gained widespread attention due to its advantages, including high confidentiality, high communication capacity, and no limitation of spectrum. One of the great challenges in FSO communication is the transmission performance degradation in atmospheric turbulence channel due to wavefront distortion and scintillation. Here, we proposed and experimentally demonstrated a 120 Gbit/s vector beam multiplexed coherent optical communication system with turbulence-resilient capacity. Four multiplexed vector beams, each carrying a 30 Gbit/s quadrature phase-shift keying signal, propagate through different turbulence conditions. The influence of turbulence channel on the vector beam impairments is experimentally investigated. Under the weaker turbulence conditions, the system bit error rates are below the forward error correction threshold of 3.8 × 10-3. In comparison with the Gaussian mode, the communication interruption probability of the vector beams system decreases from 36% to 12%-18% under stronger turbulence conditions.

Experimental demonstration of an 8-Gbit/s free-space secure optical communication link using all-optical chaos modulation.

For the first time, to the best of our knowledge, we experimentally demonstrate a high-speed free-space secure optical communication system based on all-optical chaos modulation. The effect of atmospheric turbulence on optical chaos synchronization is experimentally investigated via a hot air convection atmospheric turbulence simulator. It is shown that, even under moderately strong turbulent conditions, high-quality chaos synchronization could be obtained by increasing the transmission power. Moreover, a secure encryption transmission experiment using a high bias current induced chaotic carrier for 8-Gbit/s on-off-keying data over a ∼10-m free-space optical link is successfully demonstrated, with a bit-error rate below the FEC threshold of 3.8 × 10-3. This work favorably shows the feasibility of optical chaotic encryption for the free-space optical transmission system.

Enhanced vitamin K2 production by engineered Bacillus subtilis during leakage fermentation.

Menaquinone-7 (MK-7), a valuable member of the vitamin K2 series, is an essential nutrient for humans. It is used for treating coagulation disorders, and osteoporosis, promoting liver function recovery, and preventing cardiovascular diseases. In this study, to further improve the metabolic synthesis of MK-7 by the mutant strain, the effect of surfactants on the metabolic synthesis of MK-7 by the mutant strain Bacillus subtilis 168 KO-SinR (BS168 KO-SinR) was analyzed. The scanning electron microscopy and flow cytometry results showed that the addition of surfactants changed the permeability of the cell membrane of the mutant strain and the structural components of the biofilm. When 0.7% Tween-80 was added into the medium, the extracellular and intracellular synthesis of MK-7 reached 28.8 mg/L and 59.2 mg/L, respectively, increasing the total synthesis of MK-7 by 80.3%. Quantitative real-time PCR showed that the addition of surfactant significantly increased the expression level of MK-7 synthesis-related genes, and the electron microscopy results showed that the addition of surfactant changed the permeability of the cell membrane. The research results of this paper can serve as a reference for the industrial development of MK-7 prepared by fermentation.

Ultrasound in paediatric surgery: A meta-analysis review of its influence on postoperative wound healing and infection rates.

Ultrasound (US) has traditionally been recognised for its imaging capabilities, but its emerging role as a therapeutic modality in postoperative wound management, especially in paediatric care, has garnered significant attention. This meta-analysis aimed to evaluate the influence of US on postoperative wound healing and infection rates in paediatric patients. From an initial pool of 1236 articles, seven were deemed suitable for inclusion. Postoperative wound healing was assessed using the Redness, Edema, Ecchymosis, Discharge, and Approximation (REEDA) scale. Notably, there was a significant difference in wound healing patterns between the US-treated and control groups (I2 = 94%, standardized mean difference [SMD]: -4.60, 95% confidence intervals [CIs]: -6.32 to -2.88, p < 0.01), as illustrated in Figure 4. Additionally, a marked difference in wound infection rates was observed between the groups (I2 = 93%, SMD: -5.86, 95% CIs: -9.04 to -2.68, p < 0.01), as portrayed in Figure 5. The findings underscore the potential benefits of US in enhancing postoperative wound healing and reducing infection rates in paediatric surgical settings. However, the application of US should be judicious, considering the nuances of individual patient needs and clinical contexts.

Ultrafast Visible-Light-Induced ATRP in Aqueous Media with Carbon Quantum Dots as the Catalyst and Its Application for 3D Printing.

Photoinduced atom transfer radical polymerization (ATRP) has been proved to be a versatile technique for polymer network formation. However, the slow polymerization rates of typical ATRP limited its application in the field of additive manufacturing (3D printing). In this work, we introduced carbon quantum dots (CQDs) for the first time to the ATRP in aqueous media and developed an ultrafast visible-light-induced polymerization system. After optimization, the polymerization could achieve a high monomer conversion (>90%) within 1 min, and the polydispersity index (PDI) of the polymer was lower than 1.25. This system was then applied as the first example of ATRP for the 3D printing of hydrogel through digital light processing (DLP), and the printed object exhibited good dimensional accuracy. Additionally, the excellent and stable optical properties of CQDs also provided interesting photoluminescence capabilities to the printed objects. We deduce this ATRP mediated 3D printing process would provide a new platform for the preparation of functional and stimuli-responsive hydrogel materials.

Elastic and inelastic collision dynamics between soliton molecules and a single soliton.

Dissipative systems form various self-organized states owing to the abundant attractor structures. The study of the response of different self-organized states under collision perturbation is of great significance for understanding the dissipative nonlinear systems. The collision dynamics of single soliton and soliton molecules can not only assist the stability analysis of attractors, but also reveal the rich physical connotations of soliton interactions. Here, for the first time, the collision processes of single soliton and soliton molecules in different excited states are detected using the dispersive Fourier transform technology. The collision processes include the disintegration and rebuilding of soliton molecules as well as chaotic oscillating evolution, accompanied by the emergence of transition states such as triple binding state, soliton fusion and acceleration. According to whether the soliton molecule can return to its initial excited state, the collisions are classified as elastic and inelastic. The different interaction strength between solitons is an important condition for rebuilding stable soliton molecules. Numerical simulations show that the gain dynamics are the main physical origin of collisions. Our research will stimulate in-depth research on the interaction of self-organized states in nonlinear systems such as chemical molecules, and have potential applications in optical logic gates.

Rutin Promotes Pancreatic Cancer Cell Apoptosis by Upregulating miRNA-877-3p Expression.

(1) Background: pancreatic cancer is one of the most serious cancers due to its rapid and inevitable fatality, which has been proved very difficult to treat, compared with many other common cancers. Thus, developing an effective therapeutic strategy, especially searching for potential drugs, is the focus of current research. The exact mechanism of rutin in pancreatic cancer remains unknown. (2) Method: three pancreatic cancer cell lines were used to study the anti-pancreatic cancer effect of rutin. The potent anti-proliferative, anti-migration and pro-apoptotic properties of rutin were uncovered by cell viability, a wound-healing migration assay, and a cell apoptosis assay. High-throughput sequencing technology was used to detect the change of miRNAs expression. Immunoblotting analysis was used to detect the expression of apoptotic proteins. (3) Results: CCK-8 and EDU assays revealed that rutin significantly inhibited pancreatic cancer cells' proliferation (p < 0.05). A wound-healing assay showed that rutin significantly suppressed pancreatic cancer cells' migration (p < 0.05). A flow cytometric assay showed that rutin could promote pancreatic cancer cells' apoptosis. Intriguingly, rutin significantly upregulated miR-877-3p expression to repress the transcription of Bcl-2 and to induce pancreatic cancer cell apoptosis. Accordingly, rutin and miR-877-3p mimics could promote apoptotic protein expression. (4) Conclusions: our findings indicate that rutin plays an important role in anti-pancreatic cancer effects through a rutin-miR-877-3p-Bcl-2 axis and suggests a potential therapeutic strategy for pancreatic cancer.

[Relationship between sleep-wake circadian chronotype and anxiety and depression of medical students in a university in Wuhu City in 2020].

OBJECTIVE: To explore the circadian rhythm of sleep-wake and its relationship with anxiety and depression among medical students. METHODS: A stratified cluster random sampling method was adopted in this study, 2231 medical students in grades 1 to 3 from a medical college in Wuhu City(1004 boys and 1227 girls, aged(19.09±1.13) years) were selected in November 2020. The sleep wake circadian chronotype and mental health of medical students were evaluated by the Morningness-Eveningness Questionnaire 19(MEQ-19), the Patient Health Questionnaire 2(PHQ-2), and the Generalized Anxiety Disorder scale(GAD-2), respectively. RESULTS: The detection rates of evening chronotype, intermediate circadian chronotype, and morning chronotype were 59.84%(n=1335), 37.92%(n=846), and 2.24%(n=50), respectively. The detection rates of anxiety, depression, and anxiety combined with depression were 12.86%(n=287), 14.12%(n=315), and 9.59%(n=214), respectively. After adjusting for gender, age, grade, class performance in the last half semester, and learning burden, the result of multivariate logistic regression analysis showed that compared with medical students with intermediate circadian chronotype, medical students with evening chronotype were more likely to have anxiety(OR_(adj. )=1.403, 95% CI 1.066-1.846, P=0.016) and depression(OR_(adj. )=1.639, 95% CI 1.251-2.146, P < 0.001). CONCLUSION: The detection rate of anxiety and depression in medical students is high. The circadian chronotype of medical students is mainly evening chronotype, which is a risk factor affecting anxiety and depression among medical students.

Oscillatory self-organization dynamics between soliton molecules induced by gain fluctuation.

In passively mode-locked fiber lasers (PMLFLs), the dissipative solitons (DSs) can self-organize to form complex structures through delicate interactions. However, it is still elusive to control these soliton structures by external influences. We here find that at a certain critical power, the location between two soliton molecules can be controlled by a slow modulated pump power. After applying the pump power with periodic fluctuation, two soliton molecules oscillate from the state of soliton molecular complex to stable distribution with maximum inter-molecular separation. During this process, the internal structure of each soliton molecule keeps steady. The slow gain depletion and recovery mechanism which plays a dominant role affects the motion of soliton molecules. These results could further expand the molecular analogy of spectroscopy and stimulate the development of optical information storage and processing.

Site-directed mutagenesis of the quorum-sensing transcriptional regulator SinR affects the biosynthesis of menaquinone in Bacillus subtilis.

BACKGROUND: Menaquinone (MK-7) is a highly valuable vitamin K2 produced by Bacillus subtilis. Common static metabolic engineering approaches for promoting the production of MK-7 have been studied previously. However, these approaches caused an accumulation of toxic substances and reduced product yield. Hence, dynamic regulation by the quorum sensing (QS) system is a promising method for achieving a balance between product synthesis and cell growth. RESULTS: In this study, the QS transcriptional regulator SinR, which plays a significant role in biofilm formation and MK production simultaneously, was selected, and its site-directed mutants were constructed. Among these mutants, sinR knock out strain (KO-SinR) increased the biofilm biomass by 2.8-fold compared to the wild-type. SinRquad maximized the yield of MK-7 (102.56 ± 2.84 mg/L). To decipher the mechanism of how this mutant regulates MK-7 synthesis and to find additional potential regulators that enhance MK-7 synthesis, RNA-seq was used to analyze expression changes in the QS system, biofilm formation, and MK-7 synthesis pathway. The results showed that the expressions of tapA, tasA and epsE were up-regulated 9.79-, 0.95-, and 4.42-fold, respectively. Therefore, SinRquad formed more wrinkly and smoother biofilms than BS168. The upregulated expressions of glpF, glpk, and glpD in this biofilm morphology facilitated the flow of glycerol through the biofilm. In addition, NADH dehydrogenases especially sdhA, sdhB, sdhC and glpD, increased 1.01-, 3.93-, 1.87-, and 1.11-fold, respectively. The increased expression levels of NADH dehydrogenases indicated that more electrons were produced for the electron transport system. Electrical hyperpolarization stimulated the synthesis of the electron transport chain components, such as cytochrome c and MK, to ensure the efficiency of electron transfer. Wrinkly and smooth biofilms formed a network of interconnected channels with a low resistance to liquid flow, which was beneficial for the uptake of glycerol, and facilitated the metabolic flux of four modules of the MK-7 synthesis pathway. CONCLUSIONS: In this study, we report for the first time that SinRquad has significant effects on MK-7 synthesis by forming wrinkly and smooth biofilms, upregulating the expression level of most NADH dehydrogenases, and providing higher membrane potential to stimulate the accumulation of the components in the electron transport system.

Fluostatins M-Q Featuring a 6-5-6-6 Ring Skeleton and High Oxidized A-Rings from Marine Streptomyces sp. PKU-MA00045.

Aromatic polyketides from marine actinomycetes have received increasing attention due to their unusual structures and potent bioactivities. Compared to their terrestrial counterparts, marine aromatic polyketides have been less discovered and their structural and biological diversities are far from being fully investigated. In this study, we employed a PCR-based genome mining method to discover aromatic polyketides in our marine bacteria collection. Five new atypical angucyclinones, fluostatins M-Q (1-5) featuring a unique 6-5-6-6 ring skeleton, were discovered from one "positive" Streptomyces sp. PKU-MA00045. The structures of fluostatins M-Q (1-5) were elucidated based on comprehensive spectroscopic analyses and the crystallographic structure of fluostatin P (4), which contains the most oxidized A-ring, was solved by X-ray diffraction analysis with Cu Kα radiation. Compared to the published 16 fluostatin analogues, fluostatins M-Q (1-5) contained a different methoxy group attached at C-7 and hydroxy group attached at C-4, enriching the structural diversity of aromatic polyketides from marine actinomycetes. Genome sequencing of Streptomyces sp. PKU-MA00045 revealed the biosynthetic gene cluster of fluostatins M-Q (1-5), which contained different genes and gene organizations compared to known fluostatin gene clusters, facilitating the investigation of the biosynthesis of the unique 6-5-6-6 ring skeleton in all fluostatins.

Bacillibactin and Bacillomycin Analogues with Cytotoxicities against Human Cancer Cell Lines from Marine Bacillus sp. PKU-MA00093 and PKU-MA00092.

Nonribosomal peptides from marine Bacillus strains have received considerable attention for their complex structures and potent bioactivities. In this study, we carried out PCR-based genome mining for potential nonribosomal peptides producers from our marine bacterial library. Twenty-one "positive" strains were screened out from 180 marine bacterial strains, and subsequent small-scale fermentation, HPLC and phylogenetic analysis afforded Bacillus sp. PKU-MA00092 and PKU-MA00093 as two candidates for large-scale fermentation and isolation. Ten nonribosomal peptides, including four bacillibactin analogues (1-4) and six bacillomycin D analogues (5-10) were discovered from Bacillus sp. PKU-MA00093 and PKU-MA00092, respectively. Compounds 1 and 2 are two new compounds and the ¹H NMR and 13C NMR data of compounds 7 and 9 is first provided. All compounds 1-10 were assayed for their cytotoxicities against human cancer cell lines HepG2 and MCF7, and the bacillomycin D analogues 7-10 showed moderate cytotoxicities with IC50 values from 2.9 ± 0.1 to 8.2 ± 0.2 µM. The discovery of 5-10 with different fatty acid moieties gave us the opportunity to reveal the structure-activity relationships of bacillomycin analogues against these human cancer cell lines. These results enrich the structural diversity and bioactivity properties of nonribosomal peptides from marine Bacillus strains.

Prevalence of intestinal parasites in companion dogs with diarrhea in Beijing, China, and genetic characteristics of Giardia and Cryptosporidium species.

Companion animals including dogs are one of the important components in One Health. Parasites may cause not only diseases in pet animals but also many zoonotic diseases infecting humans. In this study, we performed a survey of intestinal parasites in fecal specimens (n = 485) collected from outpatient pet dogs with diarrhea in Beijing, China, for the entire year of 2015 by microscopic examination (all parasites) and SSU rRNA-based nested PCR detection (Giardia and Cryptosporidium). We observed a total of 124 (25.6%) parasite-positive specimens that contained one or more parasites, including Giardia duodenalis (12.8%), Cryptosporidium spp. (4.9%), Cystoisospora spp. (4.3%), trichomonads (4.3%), Toxocara canis (3.5%), Trichuris vulpis (0.6%), and Dipylidium caninum (0.2%). Among the 55 dog breeds, infection rates were significantly higher in border collies and bulldogs, but lower in poodles (p < 0.05). Risk factor analysis suggested that age was negatively correlated with the infection rate (p < 0.00001), while vaccination and deworming in the past 12 months could significantly reduce the parasite infections (p < 0.01). Among the 62 Giardia-positive specimens, 21 were successfully assigned into assemblages using glutamate dehydrogenase (gdh) and/or beta-giardin (bg) genes, including assemblage D (n = 15), C (n = 5), and F (n = 1). Among the 24 Cryptosporidium-positive specimens by SSU rRNA PCR, 20 PCR amplicons could be sequenced and identified as Cryptosporidium canis (n = 20). Collectively, this study indicates that parasites are a significant group of pathogens in companion dogs in Beijing, and companion dogs may potentially transmit certain zoonotic parasites to humans, particularly those with weak or weakened immunity.

Chiral [Mo8O26]4- Polyoxoanion-Induced Three-Dimensional Architectures With Homochiral Eight-Fold Interpenetrated Metal-Organic Frameworks.

A pair of novel chiral compounds based on homochiral 8-fold interpenetrated metal-organic frameworks (MOFs) and chiral polyoxometalates (POMs), formulated as d-[Cu(4,4'-bipy)1.5]4[Mo8O26] (d-1) and l-[Cu(4,4'-bipy)1.5]4[Mo8O26] (l-1) (4,4'-bipy = 4,4'-bipyridine), have been successfully synthesized and characterized by single crystal X-ray diffraction, infrared, thermogravimetric analysis, elemental analysis, and solid circular dichroism spectra. Structural analysis indicates that two compounds are enantiomers. The connection of copper cations and 4,4'-bipy ligands generates helical infinite chains, while adjacent chains are further linked by Cu-N bonds to form a three-dimensional interpenetrating framework with a (10,3)-a topology. Interestingly, the chiral [Mo8O26]4- polyanions are encapsulated in the chiral MOFs via sharing the oxygen atoms. Both d- and l-[Cu(4,4'-bipy)1.5]4[Mo8O26] crystallize in chiral space group C2221. Additionally, two compounds represent new examples of chiral self-assembly.

Domain structures as optical gratings controlled by electric field in a bent-core nematic.

A regular domain structure consisting of parallel stripes - flexodomains - have been induced by low frequency (subHz) electric voltage in a bent core nematic liquid crystal. The wavelength of the pattern is in the range of 1-10 micrometers and thus can conveniently be observed in a polarizing microscope. It also serves as an optical grating and produces a regular system of laser diffraction spots. The pattern was found to emerge and disappear consecutively in each half period of the driving, with the wavelength of the flexodomains changing periodically as the ac voltage oscillates. Analyzing the polarization characteristics of the diffracted light, the polarization of the first order spot was found perpendicular to that of the incident light, in accordance with a recent theoretical calculation.

Beyond surveillance: privacy, ethics, and regulations in face recognition technology.

Facial recognition technology (FRT) has emerged as a powerful tool for public governance and security, but its rapid adoption has also raised significant concerns about privacy, civil liberties, and ethical implications. This paper critically examines the current rules and policies governing FRT, highlighting the tensions between state and corporate interests on one hand, and individual rights and ethical considerations on the other. The study also investigates international legal frameworks aimed at protecting individual rights and privacy, arguing that current legislative measures often fall short of robust scholarly standards and international human rights norms. The paper concludes with recommendations for developing principled and adaptable governance frameworks that harness the benefits of FRT while mitigating its risks and negative impacts, underscoring the importance of placing human rights and ethics at the center of regulating this transformative technology.

Transcription factor MYB8 regulates iron deficiency stress response in Arabidopsis.

Iron (Fe) is a crucial microelement for humans, animals, and plants. Insufficient Fe levels in plants impede growth and diminish photosynthesis, thus decreasing crop production. Notably, approximately one-third of the soil worldwide is alkaline and prone to Fe deficiency. Therefore, understanding the mechanisms underlying Fe absorption and transportation in plants can enhance Fe bioavailability in crops. In this study, the role of the transcription factor MYB8 in plant response to Fe deficiency in Arabidopsis was investigated via reverse genetics. Phenotype analysis revealed that the functional deletion mutant of MYB8 gene exhibited sensitivity to Fe deficiency stress, as indicated by shorter root length, lower chlorophyll content, and Fe concentration. Conversely, MYB8 overexpression strain showed a tolerant phenotype. Furthermore, qRT-PCR identified possible downstream MYB8-regulated genes. Moreover, MYB8 regulated the expression of iron-regulated transporter 1 (IRT1) by binding to the MYB binding sites motif ('AACAAAC') in its promoter.

Lanthanum-modified pyroaurite as a geoengineering tool to simultaneously sink Microcystis cyanobacteria and immobilize phosphorus in eutrophic water.

Excessive phosphorus (P) in eutrophic water induces cyanobacterial blooms that aggravate the burden of in-situ remediation measures. In order to ensure better ecological recovery, Flock & Lock technique has been developed to simultaneously sink cyanobacteria and immobilize P but requires a combination of flocculent and P inactivation agent. Here we synthesized a novel lanthanum-modified pyroaurite (LMP), as an alternative for Flock & Lock of cyanobacteria and phosphorus at the background of rich humic acid and suspended solids. LMP shows a P adsorption capacity of 36.0 mg/g and nearly 100 % removal of chlorophyll-a (Chl-a), turbidity, UV254 and P at a dosage (0.3 g/L) much lower than the commercial analogue (0.5 g/L). The resultant sediment (98.2 % as immobile P) exhibits sound stability without observable release of P or re-growth of cyanobacteria over a 50-day incubation period. The use of LMP also constrains the release of toxic microcystins to 1.4 µg/L from the sunk cyanobacterial cells, outperforming the commonly used polyaluminum chloride (PAC). Similar Flock & Lock efficiency could also be achieved in real eutrophic water. The outstanding Flock & Lock performance of LMP is attributable to the designed La modification. During LMP treatment, La acts as not only a P binder by formation of LaPO4, but also a coagulant to create a synergistic effect with pyroaurite. The controlled hydrolysis of surface La(III) over pyroaurite aided the possible formation of La(III)-pyroaurite networking structure, which significantly enhanced the Flock & Lock process through adsorption, charge neutralization, sweep flocculation and entrapment. In the end, the preliminary economic analysis is performed. The results demonstrate that LMP is a versatile and cost-effective agent for in-situ remediation of eutrophic waters.

Impact of self-control and time perception on intertemporal choices in gain and loss situations.

Individuals frequently encounter dilemmas in which they must choose between smaller, immediate gains and larger, delayed rewards; this phenomenon is known as intertemporal choice. The present study analyzed the interplay of trait and state self-control and time perception tendencies (time overestimation vs. time underestimation) and how it influences the rates of selecting immediate options in both gain and loss situations by conducting an intertemporal choice task. Experiment 1 was used to explore the impact of trait self-control and time perception on intertemporal choices within gain and loss situations. In Experiment 2, the e-crossing task was used to induce self-control resource depletion in participants and to investigate the impact of self-control resources and time perception on intertemporal choices in gain and loss situations. The results indicate that (1) compared with the high-self-control group, the low-self-control group exhibited a greater tendency to choose immediate options. Additionally, the high time estimation group was more likely to opt for immediate choices than the low time estimation group was. Furthermore, participants were more likely to select immediate options in the loss situation than in the gain situation. (2) In the gain situation, the high time estimation group was more likely to choose immediate options than was the low time estimation group. However, in the loss situation, the difference between the two groups was nonsignificant. (3) Time perception and gain-loss situations exerted a moderating mediating effect on the impact of self-control resources on intertemporal choices. These findings shed light on the influence of both self-control abilities and self-control resources on intertemporal choices. They provide valuable insights into intertemporal decision behaviors across diverse contexts and indicate the need for rational analysis based on one's current state to mitigate cognitive biases to ensure individuals can maximize benefits in their daily lives.