Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 68
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Total Environ ; 927: 172262, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38583605

RESUMO

South and Southeast Asia (SSA) emitted black carbon (BC) exerts potential effects on glacier and snow melting and regional climate change in the Tibetan Plateau. In this study, online BC measurements were conducted for 1 year at a remote village located at the terminus of the Mingyong Glacier below the Meili Snow Mountains. The Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) was used to investigate the contribution and potential effect of SSA-emitted BC. In addition, variations in the light absorption characteristics of BC and brown carbon (BrC) were examined. The results indicated that the annual mean concentration of BC was 415 ± 372 ngm-3, with the highest concentration observed in April (monthly mean: 930 ± 484 ngm-3). BC exhibited a similar diurnal variation throughout the year, with two peaks observed in the morning (from 8:00 to 9:00 AM) and in the afternoon (from 4:00 to 5:00 PM), with even lower values at nighttime. At a short wavelength of 370 nm, the absorption coefficient (babs) reached its maximum value, and the majority of babs values were < 20 Mm-1, indicating that the atmosphere was not overloaded with BC. At the same wavelength, BrC substantially contributed to babs, with an annual mean of 25.2 % ± 12.8 %. SSA was the largest contributor of BC (annual mean: 51.1 %) in the study area, particularly in spring (65.6 %). However, its contributions reached 20.2 % in summer, indicating non-negligible emissions from activities in other regions. In the atmosphere, the SSA BC-induced radiative forcing (RF) over the study region was positive. While at the near surface, the RF exhibited a significant seasonal variation, with the larger RF values occurring in winter and spring. Overall, our findings highlight the importance of controlling BC emissions from SSA to protect the Tibetan Plateau against pollution-related glacier and snow cover melting.

2.
Heliyon ; 10(2): e24053, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38293444

RESUMO

After severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, a series of symptoms may persist for a long time, which is now called long COVID. It was found that long COVID can affect all patients with COVID-19. Therefore, long COVID has become a hot topic. In this study, we used the WOS database as a sample data source to conduct a bibliometric and visual analysis of 1765 long COVID articles over the past three years through VOSviewer and R package. The results show that countries/authors in Europe and The United States of America contribute most of the articles, and their cooperation is also the most active. Keyword co-occurrence identified four clusters, with important topics including the mechanism, clinical symptoms, epidemiological characteristics, and management/treatment of long COVID. Themes such as "cognitive impairment", "endothelial dysfunction", "diagnosis", and "biomarkers" are likely to be the focus of new attention in the coming period. In addition, we put forward the possible research opportunities on long COVID for researchers and practitioners to facilitate future research.

3.
J Environ Manage ; 353: 120160, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38278120

RESUMO

The partial substitution of A-site in perovskites is a major strategy to enhance the catalytic oxidation activity. This study explores the use of silver (Ag) to partially replace the lanthanum (La) ion at the A-site in LaCoO3 perovskite, investigating the role of Ag in the ABO3 perovskite structure, elucidating the nitric oxide (NO) oxidation mechanism over La1-xAgxCoO3 (x = 0.1-0.5) perovskites. La0.7Ag0.3CoO3 with an Ag-doping amount of 0.3, exhibited the highest NO oxidation activity of 88.5% at 275 °C. Characterization results indicated that Ag substitution enhanced the perovskite, maintaining its original phase structure, existing in the form of a mixture of Ag0 and Ag+ in the La1-xAgxCoO3 (x = 0.1-0.5) perovskites. Notably, Ag substitution improved the specific surface area, reduction performance, Co3+, and surface adsorption oxygen content. Additionally, the study investigated the relationship between magnetism and NO oxidation from a magnetism perspective. Ag-doping strengthened the magnetism of La-Ag perovskite, resulting in stronger adsorption of paramagnetic NO. This study elucidated the NO oxidation mechanism over La-Ag perovskite, considering structural and magnetic properties, providing valuable insights for the subsequent development and industrial application of high oxidation ability perovskite catalysts.


Assuntos
Compostos de Cálcio , Lantânio , Óxido Nítrico , Óxidos , Titânio , Lantânio/química , Propriedades de Superfície , Fenômenos Magnéticos
4.
Mater Today Bio ; 24: 100904, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38130428

RESUMO

Late detection, peritoneal dissemination, chemoresistance and weak response to targeted therapeutics lead to high mortality in ovarian cancer. More efficient and specific tumor imaging and therapeutic agents are needed to improve the resection rate of surgery and to eliminate residual disease. The expression patterns of follicle-stimulating hormone (FSH) receptor make it a suitable target for ovarian cancer. Here, we report a strategy to develop an organic near-infrared probe for FSH receptor-targeted tumor imaging and photothermal therapy. The FSH-Rh760 probe was conjugated from the Rh760 fluorophore with the FSH ß subunit 33-53 peptide. FSH-Rh760 specifically distinguished peritoneal metastatic ovarian cancerous foci from surrounding normal tissues with a high tumor-to-background ratio. The fluorescence signals in tumors peaked at 2 h and were cleared at 120 h postinjection. FSH-Rh760 treatment rapidly increased the abdomen temperature of mice up to ∼43 °C upon exposure to a near-infrared laser and effectively suppressed peritoneal tumor growth with tumor specificity. No significant systemic toxicities were observed. This study demonstrates the targeting ability and biocompatibility of FSH receptor-targeted theranostics and highlights its potential for clinical application in imaging-guided precision tumor resection and photothermal therapy to eliminate cancer lesions intraoperatively and postoperatively.

5.
Mol Imaging ; 2023: 6674054, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38089464

RESUMO

Objective: In this study, we utilized gonadotropin-releasing hormone analogue-modified indocyanine green (GnRHa-ICG) to improve the accuracy of intraoperative recognition and resection of endometriotic lesions. Methods: Gonadotropin-releasing hormone receptor (GnRHR) expression was detected in endometriosis tissues and cell lines via immunohistochemistry and western blotting. The in vitro binding capacities of GnRHa, GnRHa-ICG, and ICG were determined using fluorescence microscopy and flow cytometry. In vivo imaging was performed in mouse models of endometriosis using a near-infrared fluorescence (NIRF) imaging system and fluorescence navigation system. The ex vivo binding capacity was determined using confocal fluorescence microscopy. Results: GnRHa-ICG exhibited a significantly stronger binding capacity to endometriotic cells and tissues than ICG. In mice with endometriosis, GnRHa-ICG specifically imaged endometriotic tissues (EMTs) after intraperitoneal administration, whereas ICG exhibited signals in the intestine. GnRHa-ICG showed the highest fluorescence signals in the EMTs at 2 h and a good signal-to-noise ratio at 48 h postadministration. Compared with traditional surgery under white light, targeted NIRF imaging-guided surgery completely resected endometriotic lesions with a sensitivity of 97.3% and specificity of 77.8%. No obvious toxicity was observed in routine blood tests, serum biochemicals, or histopathology in mice. Conclusions: GnRHa-ICG specifically recognized and localized endometriotic lesions and guided complete resection of lesions with high accuracy.


Assuntos
Endometriose , Verde de Indocianina , Humanos , Feminino , Animais , Camundongos , Endometriose/diagnóstico por imagem , Endometriose/cirurgia , Endometriose/metabolismo , Diagnóstico por Imagem , Modelos Animais de Doenças , Hormônio Liberador de Gonadotropina , Imagem Óptica/métodos
6.
Artigo em Inglês | MEDLINE | ID: mdl-38153822

RESUMO

Video scene graph generation (VidSGG) aims to identify objects in visual scenes and infer their relationships for a given video. It requires not only a comprehensive understanding of each object scattered on the whole scene but also a deep dive into their temporal motions and interactions. Inherently, object pairs and their relationships enjoy spatial co-occurrence correlations within each image and temporal consistency/transition correlations across different images, which can serve as prior knowledge to facilitate VidSGG model learning and inference. In this work, we propose a spatial-temporal knowledge-embedded transformer (STKET) that incorporates the prior spatial-temporal knowledge into the multi-head cross-attention mechanism to learn more representative relationship representations. Specifically, we first learn spatial co-occurrence and temporal transition correlations in a statistical manner. Then, we design spatial and temporal knowledge-embedded layers that introduce the multi-head cross-attention mechanism to fully explore the interaction between visual representation and the knowledge to generate spatial- and temporal-embedded representations, respectively. Finally, we aggregate these representations for each subject-object pair to predict the final semantic labels and their relationships. Extensive experiments show that STKET outperforms current competing algorithms by a large margin, e.g., improving the mR@50 by 8.1%, 4.7%, and 2.1% on different settings over current algorithms.

7.
Appl Opt ; 62(28): 7463-7470, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37855515

RESUMO

To break the dependence on a high-speed and high-resolution digital-to-analog converter (DAC) in the traditional quantum noise randomized cipher (QNRC), a practical DAC-free modulation scheme based on cascaded phase-shift keying (PSK) is proposed and demonstrated by a proof-of-concept experiment. By employing seven cascaded phase modulators (PMs) driven by designed electrical voltage signals, a 128 PSK-QNRC system is achieved with a transmission rate of 10 Gbaud/s and a transmission distance more than 50 km, which eliminates the need for a DAC on the transmitter side. The bit error rate (BER) performance of the proposed scheme is compared to that of a traditional scheme based on an arbitrary waveform generator (AWG) with a sampling rate of 25 GSa/s. The results show that compared to a traditional scheme, the power penalties of the proposed scheme are -1.8d B, 0.9 dB, and 1 dB, respectively, at the rates of 10, 5, and 2.5 Gbps. In other words, the BER performance of the proposed scheme is close to the traditional scheme at a low transmission rate, but better than that of the traditional scheme at a high transmission rate, where the sampling rate of the DAC is not high enough to generate a complete waveform. This work greatly enhances the security of a QNRC system.

8.
Open Life Sci ; 18(1): 20220747, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37854319

RESUMO

Osteoarthritis (OA) is a painful joint disease that is common among the middle-aged and elderly populations, with an increasing prevalence. Therapeutic options for OA are limited, and the pathogenic mechanism of OA remains unclear. The roles of cytokines and signaling pathways in the development of OA is a current research hot spot. Interleukin (IL)-17 is a pleiotropic inflammatory cytokine produced mainly by T helper 17 cells that has established roles in host defense, tissue repair, lymphoid tissue metabolism, tumor progression, and pathological processes of immune diseases, and studies in recent years have identified an important role for IL-17 in the progression of OA. This narrative review focuses on the mechanisms by which IL-17 contributes to articular cartilage degeneration and synovial inflammation in OA and discusses how IL-17 and the IL-17 signaling pathway affect the pathological process of OA. Additionally, therapeutic targets that have been proposed in recent years based on IL-17 and its pathway in OA are summarized as well as recent advances in the study of IL-17 pathway inhibitors and the potential challenges of their use for OA treatment.

9.
Heliyon ; 9(10): e20467, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37810825

RESUMO

To effectively classify tree species within datasets characterized by limited samples, we introduced a novel approach named DenseNetBL, founded upon the fusion of the DenseNet architecture and a pivotal bottleneck layer. This bottleneck layer, encompassing a compact convolutional component, played a central role in our methodology. The evaluation of DenseNetBL was conducted under varying conditions, encompassing small-sample tree species data, extensive remote sensing datasets, and state-of-the-art classifiers. Furthermore, a quantitative assessment was executed to extract tree species areas. This was achieved by quantifying pixel areas within manually delineated tree species maps and classifier-generated counterparts. The findings of our study indicated that, in scenarios devoid of pre-trained weights, DenseNetBL consistently outperformed its DenseNet counterpart with equivalent layer numbers. In the realm of small-sample situations, both the Swin Transformer and Vision Transformer exhibited inferior performance when juxtaposed with DenseNet and DenseNetBL. Remarkably, among the shallow architectures, DenseNet33BL showcased superior aptitude for small-sample tree species classification, culminating in the most commendable results (Overall Accuracy (OA) = 0.901, Kappa = 0.892). Conversely, the Vision Transformer yielded the least favorable classification outcomes (OA = 0.767, Kappa = 0.708). The amalgamation of DenseNet33BL and simple linear iterative clustering emerged as the optimal strategy for attaining robust tree species area extraction results across two prototypical forests. In contrast, DenseNet121 exhibited suboptimal performance in the same forests, attaining the least satisfactory tree species area extraction results. These comprehensive findings underscore the efficacy of our DenseNetBL approach in addressing the challenges associated with small-sample tree species classification and accurate tree species area extraction.

10.
Appl Opt ; 62(21): 5613-5618, 2023 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-37707176

RESUMO

We propose a new, to the best of our knowledge, broadband signal downconversion scheme implemented by a monolithic integrated mutual injection laser. A mathematical derivation, simulation, and experimental verification are carried out. Because the period-one oscillation frequency can be selectively operated on a large scale by controlling the current on the integrated laser, the tuning downconversion range is realized without changing the experimental equipment. The experiment verifies that the downconversion of the linear frequency modulation signal with a bandwidth of 0.5 GHz from the center frequency of 18.75 to 0.85 GHz, and the spurious-free dynamic range (SFDR) has reached 71.7d B/H z 2/3. Compared with the scheme based on discrete components, the system has no electric local oscillator or external modulator, which provides a method for radar signal downconversion.

11.
Polymers (Basel) ; 15(18)2023 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-37765678

RESUMO

Co-pyrolysis is considered a very promising technology for the treatment of solid wastes as it can rapidly realize the volume reduction of raw materials and obtain high value-added products. To realize the resource utilization of newly emerging solid wastes in relation to edible fungi residue and waste plastics, mushroom residue (MR), a representative of edible fungi residue, was co-pyrolyzed with waste plastic bags (PE), waste plastic lunch boxes (PP), and waste plastic bottles (PET). The thermal behavior and pyrolysis kinetics of the mixtures were investigated. It was found that the softening of the plastics in the mixtures led to an increase in the initial pyrolysis temperature of MR by 2-27 °C, while the pyrolytic intermediates of MR could greatly promote the decomposition of the plastics, resulting in a decrease in the initial pyrolysis temperatures of PE, PP, and PET in the mixtures by 25, 8, and 16 °C, respectively. The mixture of MR and PE (MR/PE) under different mixture ratios showed good synergies, causing the pyrolysis peaks attributed to MR and PE to both move towards the lower temperature region relative to those of individual samples. The increase in heating rate led to enhanced thermal hysteresis of the reaction between MR and PE. The strength of the interaction between plastics and MR based on mass variation was subject to the order PE > PP > PET. The pyrolysis activation energies of MR, PE, PP, and PET calculated from kinetic analysis were 6.18, 119.05, 84.30, and 74.38 kJ/mol, respectively. The activation energies assigned to MR and plastics were both reduced as plastics were introduced to co-pyrolyze with MR, indicating that MR and plastics have a good interaction in the co-pyrolysis process. This study provides theoretical and experimental guidance for the resource utilization of agricultural solid wastes via thermochemical conversion.

12.
ACS Appl Mater Interfaces ; 15(27): 32226-32239, 2023 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-37385963

RESUMO

The high mortality rate of ovarian cancer can be primarily attributed to late diagnosis and early lymph node (LN) metastasis. The anatomically deep-located ovaries own intricate anatomical structures and lymphatic drainages that compromise the resolution and sensitivity of near-infrared first-window (NIR-I) fluorescence imaging. Reported NIR-II imaging studies of ovarian cancer focused on late-stage metastasis detection via the intraperitoneal xenograft model. However, given the significant improvement in patient survival associated with early-stage cancer detection, locating tumors that are restricted within the ovary is equally crucial. We obtained the polymer nanoparticles with bright near-infrared-II fluorescence (NIR-II NPs) by nanoprecipitation of DSPE-PEG, one of the ingredients of FDA-approved nanoparticle products, and benzobisthiadiazole, an organic NIR-II dye. The one-step synthesis and safe component lay the groundwork for its clinical translation. Benefiting from the NIR-II emission (∼1060 nm), NIR-II NPs enabled a high signal-to-noise (S/N) ratio (13.4) visualization of early-stage orthotopic ovarian tumors with NIR-II fluorescence imaging for the first time. Imaging with orthotopic xenograft allows a more accurate mimic of human ovarian cancer origin, thereby addressing the dilemma of translating existing nanoprobe preclinical research by providing the nano-bio interactions with early local tumor environments. After PEGylation, the desirable-sized probe (∼80 nm) exhibited high lymphophilicity and relatively extended circulation. NIR-II NPs maintained their accurate detection of orthotopic tumors, tumor-regional LNs, and minuscule (<1 mm) disseminated peritoneal metastases simultaneously (with S/N ratios all above 5) in mice with advanced-stage cancer in real time ∼36 h after systematic delivery. With NIR-II fluorescence guidance, we achieved accurate surgical staging in tumor-bearing mice and complete tumor removal comparable to clinical practice, which provides preclinical data for translating NIR-II fluorescence image-guided surgery.


Assuntos
Neoplasias Ovarianas , Cirurgia Assistida por Computador , Humanos , Animais , Camundongos , Feminino , Linfonodos/diagnóstico por imagem , Metástase Linfática , Neoplasias Ovarianas/diagnóstico por imagem , Neoplasias Ovarianas/patologia , Imagem Óptica/métodos , Cirurgia Assistida por Computador/métodos , Corantes Fluorescentes/química
13.
Appl Opt ; 62(7): 1689-1694, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-37132915

RESUMO

A simple and highly efficient four-channel all-optical wavelength conversion based on four-wave mixing effect of the directly modulated three-section monolithically integrated semiconductor laser is proposed and experimentally investigated. For this wavelength conversion unit, the spacing of the wavelength can be adjusted by tuning the bias current of the lasers and setting it to be 0.4 nm (50 GHz) as a demonstration is this work. A 50 Mbps 16-QAM signal centers at 4-8 GHz is experimentally switched to a targeted path. Up- or downconversion depends on a wavelength-selective switch, and the conversion efficiency can reach up to -2 to 0 dB. This work provides a new technology for photonic radio-frequency switching matrix and contributes to the integrated implementation of satellite transponders.

14.
Appl Opt ; 62(7): 1822-1828, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-37132931

RESUMO

Multi-band linearly frequency-modulated (LFM) signal generation with a multiplying bandwidth is proposed and experimentally demonstrated. It is a simple photonics method based on the gain-switching state in a distributed feedback semiconductor laser without a complex external modulator and high-speed electrical amplifiers. With N comb lines, the carrier frequency and bandwidth of generated LFM signals are N times those of the reference signal. (N is the number of comb lines.) The number of bands and time-bandwidth products (TBWPs) of the generated signals could be easily adjusted by tuning the reference signal from an arbitrary waveform generator. Three-band LFM signals with carrier frequencies ranging from the X-band to K-band are given as an example, and the TBWP up to 20000. The results of auto-correlations of the generated waveforms are also given.

15.
Diabetes Metab Syndr Obes ; 16: 331-343, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36785675

RESUMO

Background and Aims: Diabetic kidney disease (DKD) is a prevalent and intractable microvascular complication of diabetes mellitus (DM), the process of which is closely related to abnormal expression of angiogenesis-regulating factors (ARFs). Stem cell transplantation might be a novel strategy for treating DKD. This study aims to explore the effect of transplantation of human amniotic mesenchymal stem cells (hAMSCs) on renal microangiopathy in a type 1 DKD rat model (T1DRM). Methods: Seventy-two rats were randomly divided into three groups, including normal control group, DKD group, and hAMSCs transplantation group. T1DRM was established using a rat tail vein injection of streptozotocin (STZ) (55 mg/kg). hAMSCs were obtained from placental amniotic membranes during cesarean delivery and transplanted at 3 and 4 weeks through penile veins. At 6, 8, and 12 weeks following transplantation, blood glucose levels, renal function, pathological kidney alterations, and the expressions of ARFs' mRNA and protein were analyzed. Results: In T1DRM, transplanted hAMSCs that were homed at the injured site of kidneys increased ARFs' expression and decreased blood glucose levels. Compared to the DKD group, the levels of 24-h urinary protein, serum creatinine, urea, and kidney injury molecule-1 (KIM-1) were reduced in hAMSCs transplantation group. In terms of renal pathology such as the degree of basement membrane thickening, hAMSCs transplantation was also less severe than the DKD group, thereby alleviating kidney injury. Conclusion: hAMSCs transplantation might ameliorate STZ-induced chronic kidney injury through increasing ARFs' expression in kidneys and lowering blood glucose levels.

16.
Opt Express ; 31(26): 42744-42753, 2023 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-38178386

RESUMO

A novel photonic method of linearly frequency-modulated (LFM) signal generation with high purity based on the monolithically integrated semiconductor laser (MISL) subject to the dynamical optoelectrical feedback is proposed and demonstrated in this paper. In this approach, the MISL is firstly operated in period-one state. By introducing the dynamical optoelectrical feedback to modulate the MISL, the generated LFM signals would be constantly optimized as long as the delay of the feedback loop is matched with the repetition period of the LFM signal. In this system, no additional high-speed external modulator, high-frequency electrical LFM oscillator are required, highly simplifying the framework and reducing the power consumption. In the current proof-of-concept experiment, one LFM signal with the bandwidth as large as 5.6 GHz is generated and the corresponding frequency comb contrast can be drastically improved by 51 dB. Furthermore, the effect of the delay mismatch is also discussed in this paper.

17.
Front Pharmacol ; 13: 1041884, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36386149

RESUMO

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by persistent joint inflammation. In recent decades, biological agents such as anti-tumor necrosis factor-α (TNF-α) drugs have been applied in the treatment of RA and it achieved great improvement. The treatment has its side effects, but severe thrombocytopenia is very rare. In this case report we described the occurrence of severe thrombocytopenia in a patient with RA who was treated with adalimumab. Specially, the symptoms of the RA are not significantly improved by adalimumab treatment and severe thrombocytopenia it induced is resistant to treatment. After receiving four doses of adalimumab, the patient's platelet count dropped to 4 × 103/µl. We halted adalimumab and administered glucocorticoids, interleukins, and platelet transfusion. On the sixth day, the platelet count rose to 52 × 103/µl. Lab tests and bone marrow pictures were unremarkable. Patient was treated with prednisone for maintenance. On day 17, the platelet count declined to 12 × 103/µl. We started the patient on methylprednisolone and recombinant human thrombopoietin (rh-TPO), but the effect was not significant. On day 25, intravenous immune globulin (IVIG) was applied in place of the rh-TPO. On 29th day, the patient's platelets returned to normal. We summarized the existing literature on thrombocytopenia induced by anti-TNF-α drugs. This case suggested immunoglobulins could be considered for the treatment of refractory thrombocytopenia.

18.
Opt Express ; 30(12): 22153-22160, 2022 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-36224921

RESUMO

The pulse energy and average power are two long-sought parameters of femtosecond lasers. In the fields of nonlinear-optics and strong-field physics, they respectively play the role to unlock the various nonlinear processes and provide enough photon fluxes. In this paper, a high-energy and high-power Yb:CALGO regenerative amplifier with 120 fs pulse width is reported. This high-performance regenerative amplifier can work with high stability in a large tuning range of repetition rates. Varying the repetition rate from 3 to 180 kHz, the maximum output power of 36 W and the pulse energy up to 4.3 mJ, corresponding to a peak power of more than 20 GW are demonstrated. The output beam is near diffraction limited with M2 = 1.09 and 1.14 on the horizontal and vertical directions, respectively. In addition, multi-plate compression is employed to achieve 30 fs output with 23 W average power which is attractive for applications such as high-harmonic generation.

19.
J Environ Radioact ; 251-252: 106959, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35830840

RESUMO

Glaciers, as the core part of the cryosphere, are very sensitive to climate change. As an indicator of glacier changes, the characteristics of glacier-originated rivers have profound significance to global climate change and local water resources. In this paper, the Mingyong River, a glacier-originated river replenished by groundwater, was selected to study the river hydrological cycle characteristics by integrating natural tracer radium isotopes with hydrochemical parameters. The results showed that there were significant differences in radium isotope activities and hydrochemical parameters between groundwater and river water, and the radium activities increased along the river, which reflected the fact that the river was supplied by groundwater seepage. We also found that the activity ratios of 224Ra/228Ra in river and groundwater were less than one unit, which indicated that the groundwater and river water circulated rapidly and that the radioactive equilibrium of short-time radium isotopes had not yet been reached. According to the geochemical behavior of radium in river water body, the mass balance equation of radium was established. 228Ra and 224Ra were used to estimate the groundwater seepage of different segments of the Mingyong River. The results demonstrated that the groundwater seepage fluxes calculated by 224Ra and 228Ra were similar and increased along the river from 123.12 to 657.68 m3 m-1 d-1. Our results have certain significance in revealing the characteristics of the local hydrological cycle and demonstrate that radium isotopes can be used as a tool to estimate the groundwater discharge of rivers in glacial environments.


Assuntos
Água Subterrânea , Monitoramento de Radiação , Rádio (Elemento) , Monitoramento Ambiental/métodos , Camada de Gelo , Isótopos , Rádio (Elemento)/análise , Rios , Água
20.
Front Pharmacol ; 13: 806284, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35359856

RESUMO

The treatment of chronic wound is an important topic of current clinical issue. Neovascularization plays a crucial role in skin wound healing by delivering fresh nutrients and oxygen to the wound area. The aim of this study was to investigate the mechanisms of urolithin A (UA) in angiogenesis during wound healing. The results of in vitro experiments showed that treatment with UA (5-20 µM) promoted the proliferation, migration, and angiogenic capacity of HUVECs. Furthermore, we investigated the effect of UA in vivo using a full-thickness skin wound model. Subsequently, we found that UA promoted the regeneration of new blood vessels, which is consistent with the results of accelerated angiogenesis in vitro experiments. After UA treatment, the blood vessels in the wound are rapidly formed, and the deposition and remodeling process of the collagen matrix is also accelerated, which ultimately promotes the effective wound healing. Mechanistic studies have shown that UA promotes angiogenesis by inhibiting the PI3K/AKT pathway. Our study provides evidence that UA can promote angiogenesis and skin regeneration in chronic wounds, especially ischemic wounds.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...