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KDM6B-mediated epigenetic modification of the testicular regulator Dmrt1 has previously been identified as the primary switch of the male pathway in a temperature-dependent sex-determination (TSD) system; however, the molecular network of the female pathway has not yet been established. Here, we have functionally characterized for the first time an upstream regulator of the female pathway, the forkhead transcription factor FOXL2, in Trachemys scripta, a turtle species with a TSD system. FOXL2 exhibited temperature-dependent female-specific expression patterns before the onset of gonadal differentiation and was preferentially localized in ovarian somatic cells. Foxl2 responded rapidly to temperature shifts and estrogen. Importantly, forced expression of Foxl2 at the male-producing temperature led to male-to-female sex reversal, as evidenced by the formation of an ovary-like structure, and upregulation of the ovarian regulators Cyp19a1 and R-spondin1. Additionally, knockdown of Foxl2 caused masculinization at the female-producing temperature, which was confirmed by loss of the female phenotype, development of seminiferous tubules, and elevated expression of Dmrt1 and Sox9. Collectively, we demonstrate that Foxl2 expression is necessary and sufficient to drive ovarian determination in T. scripta, suggesting a crucial role of Foxl2 in female sex determination in the TSD system.
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Tortugas , Animales , Femenino , Regulación del Desarrollo de la Expresión Génica , Gónadas/metabolismo , Masculino , Procesos de Determinación del Sexo/genética , Diferenciación Sexual/genética , Temperatura , Tortugas/genéticaRESUMEN
In the analysis of both single-cell RNA sequencing (scRNA-seq) and spatially resolved transcriptomics (SRT) data, classifying cells/spots into cell/domain types is an essential analytic step for many secondary analyses. Most of the existing annotation methods have been developed for scRNA-seq datasets without any consideration of spatial information. Here, we present SpatialAnno, an efficient and accurate annotation method for spatial transcriptomics datasets, with the capability to effectively leverage a large number of non-marker genes as well as 'qualitative' information about marker genes without using a reference dataset. Uniquely, SpatialAnno estimates low-dimensional embeddings for a large number of non-marker genes via a factor model while promoting spatial smoothness among neighboring spots via a Potts model. Using both simulated and four real spatial transcriptomics datasets from the 10x Visium, ST, Slide-seqV1/2, and seqFISH platforms, we showcase the method's improved spatial annotation accuracy, including its robustness to the inclusion of marker genes for irrelevant cell/domain types and to various degrees of marker gene misspecification. SpatialAnno is computationally scalable and applicable to SRT datasets from different platforms. Furthermore, the estimated embeddings for cellular biological effects facilitate many downstream analyses.
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Perfilación de la Expresión Génica , Análisis de la Célula Individual , Programas Informáticos , Perfilación de la Expresión Génica/métodos , Análisis de la Célula Individual/métodos , TranscriptomaRESUMEN
Construction of a high-quality charge transport layer (CTL) with intimate contact with the substrate via tailored interface engineering is crucial to increase the overall charge transfer kinetics and stability for a bulk-heterojunction (BHJ) organic solar cell (OSC). Here, we demonstrate a surface chemistry strategy to achieve a homogeneous composite hole transport layer (C-HTL) with robust substrate contact by self-assembling two-dimensional tungsten disulfide (WS2) nanosheets on a thin molybdenum oxide (MoO3) film-evaporated indium tin oxide (ITO) substrate. It is found that over such a well-defined C-HTL, WS2 is homogeneously tethered on the ITO/MoO3 substrate stemming from the strong electronic coupling interaction between the building blocks, which enables a favorable interfacial configuration in terms of uniformity. As a result, the D18:L8-BO-based OSC with C-HTL exhibits a power conversion efficiency (PCE) of 19.23%, an 11% improvement over the WS2-based control device, and the highest efficiency among single-junction PEDOT-free binary BHJ OSCs.
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Nanographene C222, which consists of a planar graphenic plane containing 222 carbon atoms, holds the record as the largest planar nanographene synthesized to date. However, its complete insolubility makes the processing of C222 difficult. Here we addressed this issue by introducing peripheral substituents perpendicular to the graphene plane, effectively disrupting the interlayer stacking and endowing C222 with good solubility. We also found that the electron-withdrawing substituents played a crucial role in the cyclodehydrogenation process, converting the dendritic polyphenylene precursor to C222. After disrupting the interlayer stacking, the introduction of only a few peripheral carboxylic groups allowed C222 to dissolve in phosphate buffer saline, reaching a concentration of up to 0.5 mg/mL. Taking advantage of the good photosensitizing and photothermal properties of the inner C222 core, the resulting water-soluble C222 emerged as a single-component agent for both photothermal and photodynamic tumor therapy, exhibiting an impressive tumor inhibition rate of 96%.
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Nanopartículas , Neoplasias , Fotoquimioterapia , Humanos , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/uso terapéutico , Terapia Fototérmica , Fotoquimioterapia/métodos , Neoplasias/tratamiento farmacológicoRESUMEN
High-entropy ceramics exhibit various excellent properties owing to their high configurational entropy, which is caused by multi-principal elements sharing one lattice site. The configurational entropy will further increase significantly if multi-principal elements randomly share two different lattice sites. For this purpose, pseudobrookite phase containing two cationic lattice sites (A and B sites) is selected, and corresponding high-entropy pseudobrookite (M2+ 0.4M3+ 1.2)Ti1.4O5 is synthesized. Herein, the distribution of the 2-valent and 3-valent cations in the A and B sites are analysed in depth. The distance between the A and B sites in the crystal structure models which are constructed by the Rietveld analysis is calculated and defined as distance d. Meanwhile, the atomic column positions in the STEM images are quantified by a model-based mathematical algorithm, and the corresponding distance d are calculated. By comparing the distance d, it is determine that the 2-valent and 3-valent cations are jointly and disorderly distributed in the A and B sites in high-entropy (M2+ 0.4M3+ 1.2)Ti1.4O5. The density functional theory (DFT) simulations also demonstrate that this type of crystal structure is more thermodynamically stable. The higher degree of cationic disorder leads to a higher configurational entropy in high-entropy (M2+ 0.4M3+ 1.2)Ti1.4O5, and endows high-entropy (M2+ 0.4M3+ 1.2)Ti1.4O5 with very low thermal conductivity (1.187-1.249 W m-1 K-1).
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BACKGROUND: Sepsis can cause immune dysregulation and multiple organ failure in patients and eventually lead to death. The gut microbiota has demonstrated its precise therapeutic potential in the treatment of various diseases. This study aimed to discuss the structural changes of the gut microbiota in patients with sepsis and to analyze the differences in the gut microbiota of patients with different prognoses. METHODS: We conducted a multicenter study in which rectal swab specimens were collected on the first and third days of sepsis diagnosis. A total of 70 specimens were collected, and gut microbiota information was obtained by 16S rRNA analysis. RESULTS: The relative abundance of Enterococcus decreased in rectal swab specimens during the first three days of diagnosis in patients with sepsis, while the relative abundance of inflammation-associated Bacillus species such as Escherichia coli, Enterobacteriaceae, and Bacteroidetes increased. By comparing the differences in the flora of the survival group and the death group, we found that the abundance of Veillonella and Ruminococcus in the death group showed an increasing trend (p < 0.05), while the abundance of Prevotella_6 and Prevotella_sp_S4_BM14 was increased in surviving patients (p < 0.05). CONCLUSIONS: The Firmicutes/Bacteroidetes ratio, reflecting overall gut microbial composition, was significantly lower on day three of sepsis diagnosis. Changes in the abundance of specific gut microbiota may serve as prognostic markers in patients with sepsis.
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Microbioma Gastrointestinal , Sepsis , Humanos , Microbioma Gastrointestinal/genética , ARN Ribosómico 16S/genética , Heces , Firmicutes/genética , Sepsis/diagnóstico , Bacteroidetes/genéticaRESUMEN
OBJECTIVE: This study aimed to investigate the correlation between positive psychological capital, post-traumatic growth, social support, and quality of life (QOL) in patients with systemic lupus erythematosus (SLE). METHODS: A cross-sectional study was conducted at the First Affiliated Hospital of Xinjiang Medical University from October 2022 to May 2023. A sample of 330 hospitalized SLE patients was selected for this study. The collected data included demographic information, the SLE disease activity index, the Positive Mental Capital Questionnaire, the Chinese version of the Post-Traumatic Growth Scale, the Social Support Rating Scale, and the Chinese version of the Lupus Quality of Life Scale. RESULTS: The QOL score among the 330 SLE patients was measured as M(P25, P75) of 105 (83.00,124.00). Positive psychological capital, post-traumatic growth, and social support demonstrated significant positive correlations with the QOL in SLE patients (p < 0.05). Multiple linear regression analysis revealed that literacy, disease level, disease duration, occupation, marital status, psychological capital, social support, and post-traumatic growth were influential factors associated with the QOL in SLE patients. CONCLUSION: Medical professionals should be attentive to the psychological well-being of SLE patients and should consider implementing early psychological interventions. These interventions are crucial for enhancing the QOL for individuals diagnosed with SLE.
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Lupus Eritematoso Sistémico , Crecimiento Psicológico Postraumático , Humanos , Calidad de Vida/psicología , Estudios Transversales , Lupus Eritematoso Sistémico/complicaciones , Apoyo Social , Encuestas y CuestionariosRESUMEN
PURPOSE: In approximate 40% of thoracic endovascular aortic repair (TEVAR) procedures, the left subclavian artery (LSA) needs to be covered to obtain sufficient proximal sealing zone. To preserve the LSA during the TEVAR for type B aortic dissection (TBAD) adjacent to LSA, our team designed a modular single inner-branched stent graft. This study was performed to evaluate the safety and feasibility of deploying a modular single inner-branched stent graft in a porcine model. MATERIALS AND METHODS: Modular inner-branched stent grafts were implanted in 14 pigs via right femoral and right carotid arterial access. Computed tomography angiography (CTA) and angiography were performed in all pigs to appraise the morphological characteristics of the stent grafts at the end of follow-up. The pigs were then euthanized, and tissues were collected for gross and histological examination. RESULTS: The technical success rate was 100% (14/14). One pig suddenly died 5 hours after operation, and 1 pig died after completing the follow-up CTA. During the follow-up period, all surviving pigs showed good mental state, normal diets and activities. Computed tomography angiography examinations showed that all stent grafts were intact without fracture. All bridging covered stents were patent. Angiography showed that the position, shape, and adhesion of the stent grafts were good, and no obvious endoleaks were found. Histological examination showed that the biocompatibility of the stent grafts was good. CONCLUSIONS: This study's outcomes demonstrate that it is safe and feasible to deploy a modular single inner-branched stent graft in a porcine model. CLINICAL IMPACT: This device is the first modular device designed to treat TBAD adjacent to LSA in China. This device is a modular two-component system consisting of a thoracic aortic stent graft with a retrograde inner branch and a bridging covered stent. The modular design and the retrograde inner branch are the two important innovations of this device. Theoretically, the device could make it easier and safer for clinicians to treat TBAD adjacent to the LSA.
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PURPOSE: The purpose was to evaluate the clinical outcomes of a dedicated venous stent with the tripartite composite segments for the treatment of iliofemoral venous obstruction (IVO) in a mixed cohort of nonthrombotic iliac vein lesion (NIVL) and post-thrombotic syndrome (PTS) over a period of 12 months. METHODS: The Grency Trial is a prospective, multicenter, single-arm, open-label, pivotal study, which was conducted at 18 large tertiary hospitals in China from August 2019 to October 2020. A total of 133 hospitalized patients were screened and 110 patients with clinical, etiology, anatomical, and pathophysiology clinical class (CEAP) clinical grade C>3 and iliac vein stenosis >50% or occlusion, including 72 patients with NIVL and 38 patients with PTS, were implanted with Grency venous stents. Primary endpoint was stent patency at 12 months follow-up, and secondary outcomes were technical success; improvement in venous clinical severity score (VCSS) at 3, 6, and 12 month follow-up; and rates of clinical adverse events. RESULTS: Among 110 patients who were implanted with Grency venous stents, 107 patients completed the 12 month follow-up. All 129 stents were successfully implanted in 110 limbs. Twelve-month primary patency rate was 94.39% [95% confidence interval [CI]=88.19%-97.91%] overall, and 100% [94.94%-100%] and 83.33% [67.19%-93.63%] in the NIVL and PTS subgroups, respectively. Venous clinical severity score after iliac vein stenting improved significantly up to 12 months follow-up. There were 3 early major adverse events (1 intracerebral hemorrhage and 2 stent thrombosis events related to anticoagulation therapy), and 7 late major adverse events (1 cardiovascular death, 1 intracranial hemorrhage with uncontrolled hypertension, and 5 in-stent restenosis cases without stent fractures or migration). CONCLUSIONS: The Grency venous stent system appeared excellent preliminary safe and effective for IVO treatment. Further large-scale studies with longer-term follow-up are needed to evaluate long-term patency and durability of stent. CLINICAL IMPACT: The design of venous stents for iliofemoral venous obstruction (IVO) must address engineering challenges distinct from those encountered in arterial stenting. The Grency venous stent, a nitinol self-expanding stent specifically tailored for IVO, features a composite structure designed to meet the stent requirements of various iliac vein segments. The Grency Trial is a prospective, multicenter, single-arm, open-label pivotal study aimed at evaluating the efficacy and safety of the Grency stent system. Following a 12-month follow-up period, the Grency venous stent system has demonstrated both safety and efficacy in treating iliofemoral venous outflow obstruction.
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Various tenofovir (TFV) prodrugs have been developed by introducing masking groups to the hydroxyls of the monophosphonate group to enhance intestinal absorption efficiency and therapeutic effects. However, the reported TFV prodrugs have drawbacks such as low bioavailability, systemic toxicity caused by their breakdown in non-targeted tissues, and potential low intracellular conversion efficiency. In the present study, we developed a class of TFV monobenzyl ester phosphonoamidate prodrugs without substitutions on the benzene ring. Compared with previous TFV prodrugs, compounds 3a and 3b developed in the present study showed higher anti-hepatitis B virus activity, stronger stability and higher levels of intrahepatic enrichment of the metabolic product (TFV), indicating the potential of these compounds as novel prodrugs with high efficiency and low systemic toxicity for the treatment of hepatitis B.
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Fármacos Anti-VIH , Infecciones por VIH , Profármacos , Humanos , Tenofovir/farmacología , Tenofovir/metabolismo , Tenofovir/uso terapéutico , Fármacos Anti-VIH/uso terapéutico , Adenina/farmacología , Adenina/uso terapéutico , Profármacos/metabolismo , Anticuerpos , Infecciones por VIH/tratamiento farmacológicoRESUMEN
BACKGROUND: Neuroinflammation plays an important pathophysiological role in epilepsy; however, the precise connection between immune cells and epilepsy remains unclear. This study used Mendelian randomization (MR) to analyze the causal relationship between 731 immune cell traits and epilepsy. METHODS: Based on data from a genome-wide association study (GWAS), a bidirectional two-sample MR analysis was conducted to investigate the potential influence of immune cell phenotypes on epilepsy. Five MR methods were used to analyze the results, with the inverse variance weighted (IVW) method as the primary method, and the results were corrected using the false discovery rate (FDR) method. Sensitivity analyses were performed to test for heterogeneity and horizontal pleiotropy. RESULTS: After correction for FDR, four immune traits remained significantly associated with epilepsy risk: CD25 expression on memory (OR = 1.04, 95 % CI = 1.02 â¼ 1.06,P = 2.55 × 10-4), IgD+CD38dim (OR = 1.05, 95 % CI = 1.02 â¼ 1.08, P = 4.73 × 10-4), CD24+CD27+ (OR = 1.04, 95 % CI = 1.02 â¼ 1.06, P = 4.82 × 10-4), and IgD-CD38dim (OR = 1.04, 95 % CI = 1.02 â¼ 1.06, P = 1.04 × 10-3) B cells. The risk of generalized epilepsy was significantly associated with two immune cell traits, whereas that of focal epilepsy was significantly associated with seven immune cell traits. Furthermore, immune cell phenotypes are not affected by genetically predicted epilepsy. CONCLUSION: This MR study affirms the causal connection between circulating immune cells and epilepsy, offering guidance for further understanding of the immune mechanisms that underlie epilepsy and the discovery of novel targets for therapy.
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Epilepsia , Estudio de Asociación del Genoma Completo , Análisis de la Aleatorización Mendeliana , Fenotipo , Humanos , Epilepsia/genética , Epilepsia/inmunología , Predisposición Genética a la Enfermedad , Polimorfismo de Nucleótido SimpleRESUMEN
We designed a cascaded all-soft-glass fiber structure and simulate midinfrared 2-20 µm ultrawideband supercontinuum (SC) generation numerically. The cascaded fiber structure consists of a 1.5 m I n F 3 fiber, a 0.2 m chalcogenide photonic crystal fiber, and a 0.2 m tellurium-based chalcogenide photonic crystal fiber. Using a 2 µm pulse pumping this cascaded structure, the generated SC covering the wavelengths longer than 20 µm has been demonstrated theoretically. The 30 dB bandwidth reaches 20.87 µm from 1.44 to 22.31 µm. The effect of different pulse widths on SC generation is considered. With the increase of peak power and the decrease of pulse width, the energy of SC in the 15-20 µm waveband increases gradually. The mechanism of SC broadening process has also been analyzed. The SC generation of more than 20 µm in this cascade structure is caused by the self-phase modulation, soliton effects, four-wave mixing, and redshifted dispersive wave. This method demonstrates the possibility of generating ultrawide bandwidth SCs up to a 20 µm waveband by a commercial 2 µm pump source and all-fiber structure.
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BACKGROUND: Radiologic volumetric evaluation of Wilms' tumor (WT) is an important indicator to guide treatment decisions. However, due to the heterogeneity of the tumors, radiologists have main-guard differences in diagnosis that can lead to misdiagnosis and poor treatment. The aim of this study was to explore whether CT-based outlining of WT foci can be automated using deep learning. METHODS: We included CT intravenous phase images of 105 patients with WT and double-blind outlining of lesions by two radiologists. Then, we trained an automatic segmentation model using nnUnet. The Dice similarity coefficient (DSC) and 95th percentile Hausdorff distance (HD95) were used to assess the performance. Next, we optimized the automatic segmentation results based on the ratio of the three-dimensional diameter of the lesion to improve the performance of volumetric assessment. RESULTS: The DSC and HD95 was 0.83 ± 0.22 and 10.50 ± 8.98 mm. The absolute difference and percentage difference in tumor size was 72.27 ± 134.84 cm3 and 21.08% ± 30.46%. After optimization according to our method, it decreased to 40.22 ± 96.06 cm3 and 10.16% ± 9.70%. CONCLUSION: We introduce a novel method that enhances the accuracy of predicting WT volume by integrating AI automated outlining and 3D tumor diameters. This approach surpasses the accuracy of using AI outcomes alone and has the potential to enhance the clinical evaluation of pediatric patients with WT. By intertwining AI outcomes with clinical data, this method becomes more interpretive and offers promising applications beyond Wilms tumor, extending to other pediatric diseases.
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Neoplasias Renales , Tomografía Computarizada por Rayos X , Tumor de Wilms , Humanos , Tumor de Wilms/diagnóstico por imagen , Tumor de Wilms/patología , Neoplasias Renales/diagnóstico por imagen , Neoplasias Renales/patología , Tomografía Computarizada por Rayos X/métodos , Masculino , Femenino , Preescolar , Lactante , Niño , Carga Tumoral , Aprendizaje Profundo , Método Doble Ciego , Imagenología Tridimensional , Estudios RetrospectivosRESUMEN
Acetylacetone (AcAc) is a typical class of ß-diketones with broad industrial applications due to the property of the keto-enol isomers, but its isomerization and chemical reactions at the air-droplet interface are still unclear. Hence, using combined molecular dynamics and quantum chemistry methods, the heterogeneous chemistry of AcAc at the air-droplet interface was investigated, including the attraction of AcAc isomers by the droplets, the distribution of isomers at the air-droplet interface, and the hydration reactions of isomers at the air-droplet interface. The results reveal that the preferential orientation of two AcAc isomers (keto- and enol-AcAc) to accumulate and accommodate at the acidic air-droplet interface. The isomerization of two AcAc isomers at the acidic air-droplet interface is more favorable than that at the neutral air-droplet interface because the "water bridge" structure is destroyed by H3O+, especially for the isomerization from keto-AcAc to enol-AcAc. At the acidic air-droplet interface, the carbonyl or hydroxyl O-atoms of two AcAc isomers display an energetical preference to hydration. Keto-diol is the dominant products to accumulate at the air-droplet interface, and excessive keto-diol can enter the droplet interior to engage in the oligomerization. The photooxidation reaction of AcAc will increase the acidity of the air-droplet interface, which indirectly facilitate the uptake and formation of more keto-diol. Our results provide an insight into the heterogeneous chemistry of ß-diketones and their influence on the environment.
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Pentanonas , Agua , Isomerismo , Pentanonas/química , Agua/químicaRESUMEN
The synthesis of well-defined nanocarbon multilayers, beyond the bilayer structure, is still a challenging goal. Herein, two trilayer nanographenes were synthesized by covalently linking nanographene layers through helicene bridges. The structural characterization of the trilayer nanographenes revealed a compact trilayer-stacked architecture. The introduction of a furan ring into the helicene linker modulates the interlayer overlap and π-conjugation of the trilayer nanographenes, enabling the tuning of the interlayer coupling, as demonstrated by optical, electrochemical, and theoretical analyses. Both synthesized trilayer nanographenes are rigid chiral nanocarbons and show a chirality transfer from the helicene moiety to the stacked nanographene layers. These helical trilayer nanographenes reported here represent the covalently linked multilayer nanographenes rather than bilayer ones, showing the tunable multilayer stacking structure.
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The heterogeneous reaction of nitryl chloride (ClNO2) on the air-water surface plays a significant role in the chloride lifecycle. The air-water surface is ubiquitous on ice surfaces under supercooled conditions, affecting the uptake and heterogeneous reaction processes of trace gases. Previous studies suggest that ClNO2 is formed on Cl-doped ice surfaces following the N2O5 uptake. Herein, a distinctive heterogeneous reaction mechanism of ClNO2 is suggested on an air-water surface containing Cl under supercooled conditions using combined classic molecular dynamics (MD) and Born-Oppenheimer MD simulations. It is found that N2O5 dissociates into a NO2+ and NO3- ionic pair on the top air-water surface. In the top layer of the surface containing barely any Cl-, NO2+ proceeds through hydrolysis and produces H3O+ and HNO3. Thus, surface acidification appears because of H3O+ yields. With NO2+ diffusion to the deep layer of the surface, NO2+ reacts with Cl- and forms ClNO2. Note that ClNO2 formation competes with NO2+ hydrolysis, and the rate of ClNO2 formation is 27.7[Cl-] larger than that of NO2+ hydrolysis. Afterward, the reaction of ClNO2 with Cl- becomes barrierless with the catalysis by H3O+, which is not feasible on a neutral surface. Cl2 is thus generated and escapes into the atmosphere (low solubility of Cl2), contributing to the Cl radical. The proposed mechanism bolsters the current understanding of ClNO2's fate and its role in Cl chemistry in extremely cold environments like the Arctic and other high-latitude regions in wintertime.
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The entire decaying dynamics of harmonic mode-locking (HML) are studied utilizing the dispersive Fourier transform (DFT) technique in a SESAM-based mode-locked fiber laser. It is unveiled that the harmonic solitons do not disappear directly, but undergo transitional processes from the higher-order HML to the lower-order HML and then to the fundamental mode-locking (FML), and finally vanish. The "big corner" can also exist in the decaying process rather than just in the buildup process of HML, and there is at least one "big corner" during the decaying process between the consecutive multi-pulsing states. The energy stabilization phase (ESP) cannot be observed during every transitional process. A breathing behavior and a vibrating soliton molecule are observed in the decaying process from the 2nd HML to the FML and in the decaying process of the FML, respectively. Our work would enrich the understanding of HML behaviors and may contribute to the laser designs.
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We propose a Yb-doped fiber laser with an all-fiber beam shaper based on a single-mode-graded-index multimode-few-mode fiber (SMF-GIMF-FMF) structure. The excitation coefficients of the mode can be adjusted continuously by changing the GIMF length. Numerical simulations are performed to investigate the beam shaping dynamics in the fiber structure. Through adding the simple device geometry in the laser cavity, the switchable output between the fundamental transverse (LP01) mode and the second-order transverse (LP11) mode can be achieved. Cylindrical vector beams with high mode purity are also shown by removing the degeneracy of the LP11 mode.
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We have developed a temporal coupled-mode theory based on quasi-normal modes to investigate the chiroptical effects in parity-time (PT) symmetric metasurfaces. The PT symmetry enforces a different constraint for the direct scattering matrix and the coupling constants, which is verified by calculating the transmission spectra originating from the chiral quasi-bound states in the continuum. What's more, the scattering matrix can be analytically continued to the complex frequency plane. We find that the zero and pole singularities of the transmission coefficients and scattering matrix play an important role in the optical chirality. The pole singularities carry a quantized topological charge of -1. Our work paves the way for studying the enhanced optical chirality in non-Hermitian metasurfaces.
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The technology based on immobilized enzymes was employed to screen the constituents inhibiting disease-related enzyme activity from traditional Chinese medicine, which is expected to become an important approach of innovative drug development. Herein, the Fe3O4@POP composite with a core-shell structure was constructed for the first time with Fe3O4 magnetic nanoparticles as the core, 1,3,5-tris (4-aminophenyl) benzene (TAPB) and 2,5-divinylterephthalaldehyde (DVA) as organic monomers, and used as the support for immobilizing α-glucosidase. Fe3O4@POP was characterized by transmission electron microscopy, energy-dispersive spectrometry, Fourier transform infrared, powder X-ray diffraction, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. Fe3O4@POP exhibited a distinct core-shell structure and excellent magnetic response (45.2 emu g-1). α-Glucosidase was covalently immobilized on core-shell Fe3O4@POP magnetic nanoparticles using glutaraldehyde as the cross-linking agent. The immobilized α-glucosidase possessed improved pH stability and thermal stability as well as good storage stability and reusability. More importantly, the immobilized enzyme exhibited a lower Km value and enhanced affinity for the substrate than the free one. The immobilized α-glucosidase was subsequently used for inhibitor screening from 18 traditional Chinese medicines in combination with capillary electrophoresis analysis among which Rhodiola rosea exhibited the highest enzyme inhibitory activity. These positive results demonstrated that such magnetic POP-based core-shell nanoparticles were a promising carrier for enzyme immobilization and the screening strategy based on immobilized enzyme provided an effective way to rapidly explore the targeted active compounds from medicinal plants.