Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 87
Filtrar
Más filtros

Base de datos
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Sci Rep ; 14(1): 21504, 2024 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-39277703

RESUMEN

WSGP has demonstrated significant potential for various bioactive effects. However, limited research has explored their anti-ulcerative colitis (UC) effects and mechanism on the colonic system and gut microbial metabolites. We evaluated the ameliorative effects of WSGP on the UC mice model. Using H&E to assess histological injury of colon morphology, AB-PAS staining to detect mucin secretion from goblet cells and the mucous layer, IF to evaluate the expression of intercellular tight junction proteins, ELISA to measure inflammatory factors, WB analysis to measure protein expression of inflammatory signaling pathways, RT-qPCR to quantify gene transcription of inflammatory factors, and LC-MS to analyze metabolites in mouse cecum contents. WSGP supplementation increased food intake, body weight, and colon length while reducing disease activity and histological scores in colitis-afflicted mice. WSGP mitigated colonic tissue damage and restored intestinal barrier integrity by suppressing NF-κB/STAT3 signaling, thereby decreasing gene transcription, protein expression of proinflammatory factors, and nitric oxide production. Additionally, WSGP improved UC by altering the variety of intestinal microbial metabolites. This study demonstrates that WSGP supplementation attenuates UC mice by suppressing the NF-κB/STAT3 signaling pathway, enhancing mucosal barrier function, reducing pro-inflammatory cytokines, and modulating gut microbial metabolites.


Asunto(s)
Colitis Ulcerosa , Ajo , Microbioma Gastrointestinal , Mucosa Intestinal , Polisacáridos , Animales , Microbioma Gastrointestinal/efectos de los fármacos , Ratones , Mucosa Intestinal/metabolismo , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/microbiología , Mucosa Intestinal/patología , Polisacáridos/farmacología , Ajo/química , Colitis Ulcerosa/microbiología , Colitis Ulcerosa/tratamiento farmacológico , Colitis Ulcerosa/metabolismo , Colitis Ulcerosa/patología , Modelos Animales de Enfermedad , Masculino , Colon/metabolismo , Colon/patología , Colon/efectos de los fármacos , Colon/microbiología , Transducción de Señal/efectos de los fármacos , FN-kappa B/metabolismo , Factor de Transcripción STAT3/metabolismo , Agua , Ratones Endogámicos C57BL
2.
Cell Rep ; 43(10): 114757, 2024 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-39302836

RESUMEN

PsbS protein is essential for the rapid induction of non-photochemical quenching (NPQ) under low night temperatures (LNTs), but its stability is often affected by adverse environmental conditions. However, the regulatory mechanism for the stability of PsbS or chloroplast proteins remains to be fully characterized. We show that LNT decreases NPQ levels and SlPsbS protein abundance in tomato leaves. LNT-activated chloroplast vesicles (SlCVs) targeting the chloroplasts induce the formation of CV-containing vesicles (CCVs) containing SlPsbS, exported from the chloroplasts. Subsequently, SlCV and SlPsbS contact COP9 signalosome subunit 5A (SlCSN5A) in the cytosol and are ubiquitinated and degraded. Genetic evidence demonstrates that the overexpression of SlCV aggravates SlPsbS protein degradation, whereas silencing of SlCSN5 and SlCV delays LNT-induced NPQ reduction and SlPsbS protein turnover. This study reveals a ubiquitin-dependent degradation pathway of chloroplast proteins co-mediated by CV and CSN5A, thereby providing a basic reference for the regulation of chloroplast protein stability under stress conditions.

3.
Brain Sci ; 14(8)2024 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-39199433

RESUMEN

Heterogeneity has been one of the main barriers to understanding and treatment of autism spectrum disorder (ASD). Previous studies have identified several subtypes of ASD through unsupervised clustering analysis. However, most of them primarily depicted the pairwise similarity between individuals through second-order relationships, relying solely on patient data for their calculation. This leads to an underestimation of the complexity inherent in inter-individual relationships and the diagnostic information provided by typical development (TD). To address this, we utilized an elastic net model to construct an individual deviation-based hypergraph (ID-Hypergraph) based on functional MRI data. We then conducted a novel community detection clustering algorithm to the ID-Hypergraph, with the aim of identifying subtypes of ASD. By applying this framework to the Autism Brain Imaging Data Exchange repository data (discovery: 147/125, ASD/TD; replication: 134/132, ASD/TD), we identified four reproducible ASD subtypes with roughly similar patterns of ALFF between the discovery and replication datasets. Moreover, these subtypes significantly varied in communication domains. In addition, we achieved over 80% accuracy for the classification between these subtypes. Taken together, our study demonstrated the effectiveness of identifying subtypes of ASD through the ID-hypergraph, highlighting its potential in elucidating the heterogeneity of ASD and diagnosing ASD subtypes.

4.
BMJ Open Gastroenterol ; 11(1)2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39209333

RESUMEN

BACKGROUND: Oesophageal squamous cell carcinoma (OSCC) poses a considerable health burden, particularly in regions such as East Asia. This study aims to investigate the long-term outcomes of OSCC patients who are smokers and drinkers. MATERIALS AND METHODS: In this retrospective analysis, data from Sichuan Cancer Hospital and Institute Esophageal Cancer Case Management Database between January 2010 and December 2017 were examined. Patients were categorised into different groups based on their smoking and alcohol consumption history: None, Smoker, Non-Smoker, Smoke-Only, Drinker, Non-Drinker, Drinker-Only, and Both. Survival outcomes were compared between the groups using Kaplan-Meier analysis and propensity score matching (PSM). The primary outcome was overall survival (OS), measured from surgery to death or last follow-up in April 2022. RESULTS: The OS median was 45.4 months for all patients after oesophagectomy. Smokers had a significantly lower median OS of 36.6 months compared with Non-Smokers with 66.2 months (p<0.001). Similarly, Drinkers had a lower median OS of 34.4 months compared with Non-Drinkers with 52.0 months (p<0.001). PSM analysis confirmed the significant differences in OS between Smokers and Non-Smokers (p=0.002) and between Drinkers and Non-Drinkers (p=0.002). Subgroup analyses showed no significant differences in OS between Group Another and Group Both, Group Smoker-Only and Group Drinker-Only, and Group Drinker-Only and Group Both. (figure 4) CONCLUSION: Smoking and drinking were associated with significantly reduced OS in patients. However, no significant differences were found between the subgroups of patients who only smoked, only drank, or engaged in both habits.


Asunto(s)
Consumo de Bebidas Alcohólicas , Neoplasias Esofágicas , Carcinoma de Células Escamosas de Esófago , Esofagectomía , Puntaje de Propensión , Fumar , Humanos , Esofagectomía/efectos adversos , Masculino , Femenino , Persona de Mediana Edad , Carcinoma de Células Escamosas de Esófago/cirugía , Estudios Retrospectivos , Neoplasias Esofágicas/cirugía , Neoplasias Esofágicas/mortalidad , Consumo de Bebidas Alcohólicas/efectos adversos , Consumo de Bebidas Alcohólicas/epidemiología , Fumar/efectos adversos , Fumar/epidemiología , Anciano , Fumadores/estadística & datos numéricos , China/epidemiología , Estimación de Kaplan-Meier , Resultado del Tratamiento
5.
ACS Omega ; 9(28): 30826-30833, 2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-39035977

RESUMEN

In pursuit of accessing clean water, the phosphate removal is of great importance for preventing eutrophication toward sustainable ecology. However, effective adsorbents with high capacity, selectivity, and long-term stability for treating phosphate in water still remain desired, which requires further development. Herein, a type of porous La-based adsorbents, which are composed of highly dispersed La(OH)3 on amino-functionalized Caragana korshinskii (CK) nanowires, are designed and fabricated through simple amination and decoration of lemon bars. Specifically, the adsorption to phosphate can be quickly completed within 50 min, and an ultrahigh adsorption capacity of 173.3 mg of P g-1 is realized. Moreover, these composite adsorbents display excellent selectivity and anti-interference ability to phosphate in the presence of common anions (CO3 2-, NO3-, Cl-, and SO4 2-). After four regenerations, there is still a removal rate of 85%. This study underscores an integrated material model for designing advanced structures toward efficient wastewater treatment.

6.
Materials (Basel) ; 17(14)2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-39063718

RESUMEN

Yttrium aluminum garnet (YAG)-based optical fiber is one of the research hotspots in the field of fiber lasers due to its combined advantages of a wide doping range of rare earth ions and the high mechanical strength of YAG material, as well as the flexibility and small size of the fiber structure. YAG-based optical fibers and related laser devices can be used in communication, sensing, medicine, etc. A comprehensive review of YAG-based optical fibers is provided in this paper. Firstly, the fabrication processes of YAG-based optical fibers are summarized and the structure and properties of fibers are classified and compared. Secondly, according to the optical wavelength regions, rare earth-doped YAG-based optical fibers for the applications of single-frequency and mode-locked fiber lasers are summarized. Lastly, the development challenges in both the fabrication and applications of YAG-based optical fibers are discussed.

7.
Thromb J ; 22(1): 69, 2024 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-39075498

RESUMEN

OBJECTIVE: Thromboangiitis obliterans (TAO) remains clinical challenging due to its rarity and underwhelming management outcomes. This study aimed to describe a novel TAO rabbit model that demonstrates a closer resemblance to TAO. METHODS: Thirty-six New Zealand rabbits underwent the surgical implantation of calibrated gelatin sponge particles (CGSPs) into their right femoral artery. The CGSPs were soaked in different solutions to simulate different types of thrombi: normal (NT; normal saline); inflammatory TAO thrombus (TAO; dimethylsulfoxide [DMSO]), and DMSO with methotrexate (MTX). All groups underwent clinical assessment, digital subtraction angiography (DSA) and histopathological analysis at time points day 0 (immediate), week 1 (acute), week 2 (subacute), and week 4 (chronic). RESULTS: The TAO rabbit presented with signs of ischemia of the right digit at week 4. On DSA, the TAO rabbits exhibited formation of corkscrew collaterals starting week 1. On H&E staining, gradual CGSP degradation was observed along with increased red blood cell aggregation and inflammatory cells migration in week 1. On week 2, disorganization of the tunica media layer and vascular smooth muscle cell (VSMC) proliferation was observed. In the TAO rabbit, migrated VSMCs, inflammatory cells, and extracellular matrix with collagen-like substances gradually occluded the lumen. On week 4, the arterial lumen of the TAO rabbit was filled with relatively-organized VSMC and endothelial cell clusters with less inflammatory cells. Neorevascularization was found in the MTX-treated group. CONCLUSION: The novel TAO rabbit model shows a closer resemblance to human TAO clinically, radiographically, and histopathologically. Histological analysis of the IT progression in the TAO model suggests that it is of VSMC origin.

8.
Environ Pollut ; 360: 124609, 2024 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-39074690

RESUMEN

Fluorochemical industry is an emerging industry leading to environmental emissions of fluoride ion, fluorinated greenhouse gases (GHGs) and per- and polyfluoroalkyl substances (PFASs) globally. Chlorofluorocarbon (CFCs) and hydrochlorofluorocarbon (HCFCs) are the primary causes of ozone layer depletion, and together with hydrofluorocarbons (HFCs), they contribute to global climate warming. PFAS are emerging persistent organic pollutants, comprising thousands of materials including perfluoroalkyl acids (PFAAs), perfluoroalkane sulfonamides (FASAs), and fluoropolymers.As the implementation of the Montreal Protocol and the Stockholm Convention makes progress, fluorochemical industry is searching for alternatives like HFCs, perfluoroalkyl ether carboxylic acids (PFECAs) and etc. Even though studies on chemical processes and environmental influences of the fluorochemical industry are plentiful, research on emissions of fluorine chemicals from different fluorochemical industry is still scarce. In this study, we conducted on-site sampling to analyze the distribution of fluorine chemicals in the surrounding environment of the fluorochemical industrial sites. The sampling sites represent different stages of fluorochemical industry production, including fluorite mining, synthesis of fluorochemical raw materials like fluorocarbons, and fine fluorine product processing which is mostly PFAS. Results show that at the fluorite mining stage, concurrent emissions of fluoride ion and CFC-12 contribute to the primary environmental issue. Perfluorooctanoic acid (PFOA) and some short-chain PFASs like perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluoroheptanoic acid (PFHpA), and perfluorobutanesulfonic acid (PFBS) are the main pollutants from fluocarbons production, accompanied by emissions of fluorinated GHGs such as HFC-32, and HCFC-22. At the fine fluorine product synthesis stage where produces fluoropolymers, perfluoropolyethers and fluorinated surfactants, PFAS especially for emerging alternatives PFECAs like hexafluoropropylene oxide dimer acid (HFPODA) and Perfluoro-4-oxapentanoic acid (PF4OPeA), as well as fluorinated GHGs like HFC-23 and HFC-227ea, require increasing attention.


Asunto(s)
Contaminantes Atmosféricos , Monitoreo del Ambiente , Fluoruros , Fluorocarburos , Gases de Efecto Invernadero , Fluorocarburos/análisis , Fluoruros/análisis , Monitoreo del Ambiente/métodos , Contaminantes Atmosféricos/análisis , Gases de Efecto Invernadero/análisis , Caprilatos/análisis , Industria Química
9.
Fundam Res ; 4(2): 334-343, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38933520

RESUMEN

By conducting a two-dimensional experimental study, this paper aims to enhance the understanding of the mechanism of sand convective motions in the vicinity of a wall subjected to long-term cyclic lateral loadings. The experimental tests were conducted in a rectangular sandbox with a transparent front-wall, through which the process of sand particle motions could be recorded by using a high-resolution digital camera. The images were processed with a high time-resolved PIV (Particle Image Velocimetry) system. Based on the experimental data, this work (1) presents the sand flow field in the convective zones; (2) provides means to describe the convection mechanism; (3) proposes the relationships between the loading conditions and dimensions of the region with intense sand movement; and (4) elaborates the similarity of the sand flow velocity structure within the sand convective zones.

10.
BMC Musculoskelet Disord ; 25(1): 472, 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-38880874

RESUMEN

BACKGROUND: Scoliosis is a high incidence disease that endangers the physical and mental health of adolescents. Traction therapy, as a conservative treatment plan, is helpful to improve the recovery speed of patients by studying the influence of different traction factors on the therapeutic effect. METHODS: Based on the thin layer CT data of the lumbar spine of a 16-year-old patient with scoliosis, Mimics21.0 was used to extract the 3D digital model, and Geomagic Wrap2021 was used to perform the smooth surface. After that, SolidWorks was used to manually construct the structures, such as the intervertebral disc, and Ansys17.0 was used to add constraints, ligaments, and other features. Three-factor ANOVA was carried out after an orthogonal experiment that considered traction mode, traction angle, and traction force was finished. RESULTS: ① A three-dimensional biomechanical model of lumbar scoliosis was created. ② The model's correctness was confirmed by comparing it to the corpse and other finite element models, as well as by verifying it under a range of working settings. ③ Traction force (P = 0.000), traction angle (P = 0.000), the interaction between traction force and traction angle (P = 0.000), and the interaction between traction mode and traction angle (P = 0.045) were all significant. ④ The interaction between traction force and traction angle has the most significant effect on Cobb, and traction with a certain angle is better than traditional axial traction. ⑤ Traction mode is not significant, but the interaction between traction mode and traction angle is significant. CONCLUSIONS: A certain angle of traction can aid in improving outcomes and the traction force can be suitably decreased in the clinical formulation of the traction plan. The uniformity of correcting effect is more favorable when higher fixation techniques like positive suspension or traction bed traction are used, as opposed to overhanging traction.


Asunto(s)
Análisis de Elementos Finitos , Vértebras Lumbares , Escoliosis , Tracción , Humanos , Tracción/métodos , Escoliosis/terapia , Escoliosis/diagnóstico por imagen , Escoliosis/fisiopatología , Vértebras Lumbares/diagnóstico por imagen , Adolescente , Imagenología Tridimensional , Fenómenos Biomecánicos , Tomografía Computarizada por Rayos X , Resultado del Tratamiento
12.
J Gastrointest Surg ; 28(5): 611-620, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38704198

RESUMEN

PURPOSE: With the rising life expectancy and an aging population, it has become increasingly important to investigate treatments suitable for older adult patients with esophageal cancer. This study investigated whether older adult patients who underwent esophagectomy had better clinical outcomes than those who were nonsurgically treated. METHODS: We retrospectively analyzed patients with esophageal squamous cell carcinoma (ESCC) who were 70 years or older and underwent esophagectomy, radiotherapy (RT), and/or chemoradiotherapy (CRT) between January 2018 and December 2019. Patients were divided into 2 groups: the surgery group (S group) and the nonsurgery group (NS group). We then compared the clinical outcomes of the 2 groups. RESULTS: After a median follow-up duration of 36.6 months, the S group showed better overall survival (OS). The 3-year OS was 59% in the S group and 27% in the NS group (hazard ratio [HR], 0.397; 95% CI, 0.278-0.549; P < .0001). In the S group, the median progression-free survival was 38.3 months (95% CI, 30.6-46.1) compared with 12.3 months in the NS group (HR, 0.511; 95% CI, 0.376-0.695; P < .0001). In addition, the number of adverse events in the NS group was higher than that in the S group (P < .001). CONCLUSION: Overall, patients with ESCC at the age of ≥70 years who underwent esophagectomy had significantly better clinical outcomes than those who underwent nonsurgical treatment with RT and/or CRT.


Asunto(s)
Neoplasias Esofágicas , Carcinoma de Células Escamosas de Esófago , Esofagectomía , Puntaje de Propensión , Humanos , Masculino , Anciano , Femenino , Neoplasias Esofágicas/terapia , Neoplasias Esofágicas/mortalidad , Neoplasias Esofágicas/patología , Estudios Retrospectivos , Carcinoma de Células Escamosas de Esófago/terapia , Carcinoma de Células Escamosas de Esófago/mortalidad , Carcinoma de Células Escamosas de Esófago/patología , Carcinoma de Células Escamosas de Esófago/cirugía , Anciano de 80 o más Años , Quimioradioterapia , Tasa de Supervivencia , Resultado del Tratamiento , Factores de Edad , Supervivencia sin Progresión
13.
Med Image Anal ; 94: 103148, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38554550

RESUMEN

Deep learning methods show great potential for the efficient and precise estimation of quantitative parameter maps from multiple magnetic resonance (MR) images. Current deep learning-based MR parameter mapping (MPM) methods are mostly trained and tested using data with specific acquisition settings. However, scan protocols usually vary with centers, scanners, and studies in practice. Thus, deep learning methods applicable to MPM with varying acquisition settings are highly required but still rarely investigated. In this work, we develop a model-based deep network termed MMPM-Net for robust MPM with varying acquisition settings. A deep learning-based denoiser is introduced to construct the regularization term in the nonlinear inversion problem of MPM. The alternating direction method of multipliers is used to solve the optimization problem and then unrolled to construct MMPM-Net. The variation in acquisition parameters can be addressed by the data fidelity component in MMPM-Net. Extensive experiments are performed on R2 mapping and R1 mapping datasets with substantial variations in acquisition settings, and the results demonstrate that the proposed MMPM-Net method outperforms other state-of-the-art MR parameter mapping methods both qualitatively and quantitatively.


Asunto(s)
Algoritmos , Procesamiento de Imagen Asistido por Computador , Metacrilatos , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Encéfalo , Imagen por Resonancia Magnética/métodos
14.
Adv Mater ; 36(28): e2402239, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38519452

RESUMEN

In this work, a distinctive "metal-ion organic hybrid interface" (MOHI) between polyimide (PI) and calcium niobate (CNO) nanosheets is designed. The metal ions in the MOHI can achieve atomic-level matching not only with the inorganic CNO, but also with the PI chains, forming uniform and strong chemical bonds. These results are demonstrated by experiment and theory calculations. Significantly, the MOHI reduces the free volume and introduces deep traps across the filler-matrix interfacial area, thus suppressing the electric field distortion in PI-based composite dielectrics. Consequently, PI-based dielectric containing the MOHI exhibits excellent energy storage performance. The energy storage densities (Ue) of the composite dielectric reach 9.42 J cm-3 and 4.75 J cm-3 with energy storage efficiency (η) of 90% at 25 °C and 150 °C respectively, which are 2.6 and 11.6 times higher than those of pure PI. This study provides new ideas for polymer-based composite dielectrics in high energy storage.

15.
Clin Exp Hypertens ; 46(1): 2328147, 2024 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-38488417

RESUMEN

BACKGROUND: Several studies indicate that the cystathionine ß-synthase (CBS) gene T833C, G919A and 844ins68 polymorphisms in the 8th exon region may be correlated with coronary artery disease (CAD) susceptibility, but the results have been inconsistent and inconclusive. Thus, a meta-analysis was conducted to provide a comprehensive estimate of these associations. METHODS: On the basis of searches in the PubMed, EMBASE, Cochrane Library, Wanfang, VIP, and CNKI databases, we selected 14 case - control studies including 2123 cases and 2368 controls for this meta-analysis. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated accordingly using a fixed-effect or random-effect model. RESULTS: The results indicated an increased risk between the CBS T833C gene polymorphisms and susceptibility to CAD under the dominant model (CC+CT vs. TT: OR = 1.92, 95% CI: 1.11 ~ 3.32), recessive model (CC vs. CT+TT: OR = 1.88, 95% CI: 1.17 ~ 3.03), and homozygous model (CC vs. TT: OR = 2.46, 95% CI: 1.04 ~ 5.83). In these three genetic models, no significant association was identified for CBS G919A (AA+AG vs. GG: OR = 1.48, 95% CI: 0.45 ~ 4.82),(AA vs. AG+GG: OR = 1.58, 95% CI: 0.93 ~ 2.70),(AA vs. GG: OR = 1.66, 95% CI: 0.40 ~ 6.92) or CBS 844ins68 (II+ID vs. DD: OR = 1.04, 95% CI: 0.80 ~ 1.35),(II vs. ID+DD: OR = 1.09, 95% CI: 0.51 ~ 2.36),(II vs. DD: OR = 1.10, 95% CI: 0.51 ~ 2.39). CONCLUSIONS: This meta-analysis suggests that the CBS T833C gene polymorphism is significantly associated with the risk of CAD and it shows a stronger association in Asian populations. Individuals with the C allele of the CBS gene T833C polymorphism might be particularly susceptible to CAD.


Asunto(s)
Enfermedad de la Arteria Coronaria , Humanos , Enfermedad de la Arteria Coronaria/genética , Cistationina betasintasa/genética , Polimorfismo Genético , Homocigoto , Exones/genética , Predisposición Genética a la Enfermedad , Polimorfismo de Nucleótido Simple/genética
16.
Org Lett ; 26(11): 2266-2270, 2024 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-38451860

RESUMEN

A sustainable, cyanide-free synthesis of alkyl nitriles via the aerobic oxidative deconstruction of unstrained cycloalkanones with ammonium salts has been developed. Using inexpensive and stable ammonium salts as the nitrogen source, a variety of alkyl nitriles containing a distal carbonyl group were obtained in good yields under visible-light-promoted iron catalysis. This protocol is characterized by mild conditions, abundant and environmentally benign materials, and high atom and step economy with minimal waste generation. The primary mechanism study revealed that 1O2 is likely to be involved in this reaction.

17.
Opt Express ; 32(4): 4944-4953, 2024 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-38439233

RESUMEN

Single-frequency fiber lasers at S-, C-, and L-bands play a crucial role in various applications such as optical network expansion, high-precision metrology, coherent lidar, and atomic physics. However, compared to the C-band, the S- and L-bands have wavelength deviations and suffer from excited-state absorption, which limits the output performance. To address this issue, a strategy called ion hybridization has been proposed to increase the differences in site locations of rare earth (RE) ions in the laser matrix, thereby achieving a broader gain bandwidth. This strategy has been applied to an Er3+/Yb3+ co-doped modified phosphate fiber (EYMPF), resulting in gain coefficients per unit length greater than 2 dB/cm at S-, C-, and L-bands. To demonstrate its capabilities, several centimeter-long EYMPFs have been used to generate single-frequency laser outputs at S-, C- and L-bands with kHz-linewidths, high signal-to-noise ratios (>70 dB), and low relative intensity noise (<-130 dB/Hz) in a compact short linear-cavity configuration.

18.
JACS Au ; 4(2): 491-501, 2024 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-38425939

RESUMEN

Site-selective excitation (SSE), which is usually realized by tuning the wavelength of absorbed light, is an ideal way to study bond-selective chemistry, analyze the crystal structure, investigate protein conformation, etc., eventually leading to active manipulation of desired processes. Herein, SSE has been explored in (110)-, (100)-, and (011)-faced rutile TiO2, a prototypical material in both surface science and photocatalysis fields. Using ultraviolet photoelectron spectroscopy and photon energy-, substrate orientation-, and laser polarization-dependent two-photon photoemission spectroscopy (2PPE), intra-atomic 3d → 3d transition from the split Ti3+ 3d orbitals, i.e., band gap states and excited states at ∼1.00 eV below and ∼2.40 eV above the Fermi level, respectively, has been proven for all of the samples, suggesting that it is a common property of this material. The distinct structure of rutile TiO2 results in the anisotropic 3d → 3d transitions with the transition dipole moment along the long axes ([110] and [11̅0]) of TiO6 blocking units. This anisotropy facilitates the selective excitation of Ti3+ ions in the two types of TiO6, which cannot be realized by conventional wavelength tuning, via polarization alignment of the excitation source. Discovery in this work builds the foundation for future investigation of site-selective photophysical and photochemical processes and eventually possible active manipulation in this material at the atomic level.

19.
Opt Lett ; 49(3): 434-437, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38300025

RESUMEN

Single-frequency fiber lasers (SFFLs), 1083 nm, have been extensively applied in 4He optical pumping magnetometers (OPMs) for magnetic field detection. However, the sensitivity and accuracy of OPMs are constrained by the frequency stability of SFFLs. Focusing on this concern, the frequency-stabilized performance of the 1083 nm SFFLs is successfully improved by externally tailoring the laser linewidth to match the spectral width of the error signal in saturated absorption spectroscopy. Thereinto, a high-intensity error signal of saturated absorption is generated as a large number of 4He atoms with a wide range of velocities interacting with the 1083 nm laser. Consequently, the root mean square value of the fluctuating frequency after locking is effectively decreased from 24.6 to 13.6 kHz, which achieves a performance improvement of 44.7%. Such a strategy can provide a technical underpinning for effectuating an absolute frequency stabilization with higher precision based on atomic and molecular absorption spectroscopy techniques.

20.
Nat Commun ; 15(1): 1839, 2024 Feb 29.
Artículo en Inglés | MEDLINE | ID: mdl-38424039

RESUMEN

Untethered capsules hold clinical potential for the diagnosis and treatment of gastrointestinal diseases. Although considerable progress has been achieved recently in this field, the constraints imposed by the narrow spatial structure of the capsule and complex gastrointestinal tract environment cause many open-ended problems, such as poor active motion and limited medical functions. In this work, we describe the development of small-scale magnetically driven capsules with a distinct magnetic soft valve made of dual-layer ferromagnetic soft composite films. A core technological advancement achieved is the flexible opening and closing of the magnetic soft valve by using the competitive interactions between magnetic gradient force and magnetic torque, laying the foundation for the functional integration of both drug release and sampling. Meanwhile, we propose a magnetic actuation strategy based on multi-frequency response control and demonstrate that it can achieve effective decoupled regulation of the capsule's global motion and local responses. Finally, through a comprehensive approach encompassing ideal models, animal ex vivo models, and in vivo assessment, we demonstrate the versatility of the developed magnetic capsules and their multiple potential applications in the biomedical field, such as targeted drug delivery and sampling, selective dual-drug release, and light/thermal-assisted therapy.


Asunto(s)
Sistemas de Liberación de Medicamentos , Enfermedades Gastrointestinales , Animales , Fenómenos Físicos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA