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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120230, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34358784

RESUMO

Luminescent metal-organic frameworks (LMOFs) and their functional materials with unique characteristics can provide the basis for the construction of new analytical techniques, which can meet the continuous demand for various fields. In this work, guanosine monophosphate (GMP), terbium ion (Tb3+) and zeolitic imidazolate framework-8 (ZIF-8) are self-assembled to form a ZIF-8@GMP-Tb nanocomplex, which can be utilized as a ratiometric fluorescent probe to monitor alkaline phosphatase (ALP) activity. Specifically, with adding ALP, the fluorescence intensity at 547 nm (one of the characteristic emission peaks of Tb3+) obviously decreased. Meanwhile, the conjugated structure of GMP increased the fluorescence of ZIF-8 (located at 330 nm). The possible mechanism was proposed through the characterization of the materials. Based on the variation of the emission peaks at 330 and 547 nm, the ratiometric fluorescent sensor of ALP has a linear range of 0.25-20 U/L. Moreover, applying this sensing system to the detection of ALP in the human serum sample and ALP inhibitor investigation possesses satisfactory results. This work provides a new perspective for the utilization of ZIF-8 and lanthanide ions in manufacturing simple and sensitive sensors.


Assuntos
Guanosina Monofosfato , Zeolitas , Fosfatase Alcalina , Corantes Fluorescentes , Humanos , Térbio
2.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120295, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34450572

RESUMO

Cerium, an abundant lanthanide element, is widely used in human industry. The accumulation of Ce4+ ion, however, will damage the environment and biological organism. Therefore, its facile detection is highly needed. Herein, we design a hybrid sensing platform consisting of carbon dots (C-dots) and bathophenanthroline-disulfonate-Fe2+ complex (Bphen-Fe2+) for trace-level determination of Ce4+. Based on inner filter effect (IFE), the red-colored Bphen-Fe2+ complex severely quenches the fluorescence of C-dots. After addition of Ce4+, Fe2+ is oxidized to Fe3+, and the colorless Bphen-Fe3+ complex generates, which weakens the IFE efficiency and leads to the fluorescence recovery of C-dots. Meanwhile, due to the decreasing amount of Bphen-Fe2+ upon Ce4+ addition, the red color of the solution gradually fades, which enables visual detection of Ce4+ by the naked eyes. Under the optimized conditions, the C-dots/Bphen-Fe2+ system realizes the fluorometric and colorimetric sensing of Ce4+ in the range of 0.5-100 and 1.9-80 µM, with the limits of detection as low as 0.5 and 1.9 µM, respectively. This method also shows high selectivity over other common ions, and has an excellent applicability for monitoring of Ce4+ in real water samples.


Assuntos
Cério , Pontos Quânticos , Carbono , Colorimetria , Humanos , Íons , Fenantrolinas
3.
Carbohydr Polym ; 275: 118762, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34742450

RESUMO

Fungal keratitis remains a serious infectious ocular disease, and the traditional administration of eye drops is limited by ocular intrinsic barriers and drug shortages. Herein, we fabricated a chitosan-based dual-functional platform for ocular topical delivery of econazole. The platform can prolong the residence time on the ocular surface due to its strong interaction with the mucin layer by physical adhesion and covalent bonding, and also open corneal epithelial tight junctions for being positively charged, thereby enhancing corneal penetration of drug. Using these strategies, dosing concentration was reduced from 0.3 wt% to 0.1 wt%, dosing frequency was reduced from once-an-hour to twice-daily, in vitro and in vivo antifungal therapeutic effects were achieved and patient compliance could be improved. Given its high structural adaptability, many other ocular anterior segment-related diseases would benefit from this platform.

4.
Artigo em Inglês | MEDLINE | ID: mdl-34741747

RESUMO

This study investigates the effect of income inequality and institutional quality on carbon emission in 180 countries of the world from 2002 to 2019. The study employed OLS, fixed effect, and system generalized method of moments (SGMM), and the results show that income inequality, institutional quality, financial development, and economic growth have a direct significant and positive effect on carbon emission while trade openness and renewable energy significantly reduce carbon emission. VOA, ROL from the legal system, and GOV from the political system negatively affect carbon emission while the interaction term between GDP and GINI is found negative for carbon emission while the interaction of FD and GINI, INST and GINI, FD, and GDP are positively linked with carbon emission. The EKC hypothesis has been evidenced in the analysis with all INST indices. Our findings have considerable policy implications for the sample countries regarding the income inequality and institutions' development toward environmental quality enrichment.

5.
China CDC Wkly ; 3(43): 897-900, 2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34745687

RESUMO

What is already known about this topic?: Benzene is classified as a Class I human carcinogen by the International Agency for Research on Cancer. Long-term exposure to benzene increases the risk of chronic benzene poisoning and leukemia. However, benzene is still widely used in the manufacturing industry. What is added by this report?: The scale of enterprises most exposed to benzene was small enterprises, and joint-equity enterprises had the highest number that exceeded the permissible concentration-time weighted average. What are the implications for public health practice?: It is still necessary to strengthen the monitoring of benzene concentrations in the manufacturing industry, especially in small enterprises. The occupational exposure limit of benzene should be appropriately reduced.

6.
Front Mol Biosci ; 8: 717962, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34760922

RESUMO

Exposure to high levels of ozone contributes to insensitivity to glucocorticoids in asthma treatment, but the underlying mechanisms are not known. We built two asthma models: a "T2-high" asthma model was established by ovalbumin (OVA) sensitization/challenge and OVA sensitization/challenge combined with ozone exposure (OVA + ozone) was used to induce airway inflammation with increased numbers of neutrophils to simulate "T2-low" asthma. The expression of T-helper (Th)1/2/17-related cytokines was measured by cytokine antibody arrays. Bronchial provocation tests were carried out to evaluate the lung resistance of mice. Hematoxylin and eosin staining, periodic acid-Schiff staining, and immunohistochemical (IHC) analyses of alpha-smooth muscle actin were undertaken to observe morphology changes in lungs. The expression of glucocorticoid receptors (GRs) and phosphorylated-GR (p-GR) was measured by western blotting. Nr3c1 mRNA was quantified by RT-qPCR. Protein expression of proinflammatory cytokines, signal transducer and activator of transcription 3 (STAT3), suppressor of cytokine signaling 3 (SOCS3), and CXCL1 was measured through ELISAs, western blotting, or IHC analyses. Resected lung tissue from seven asthma patients and 10 healthy controls undergoing thoracotomy for pulmonary nodules was evaluated by IHC analyses and ELISAs. In both asthma models, mucus hypersecretion, as well as inflammation, hyperresponsiveness, and remodeling of the airways, was present compared with the control group, whereas the OVA + ozone group showed severe neutrophil infiltration. The expression of Th17-related cytokines (interleukin (IL)-6, IL-17A, IL-21), GR protein, and CXCL1 increased in the OVA + ozone group, whereas the expression of p-GR decreased. Dexamethasone (Dex) could not totally reverse the expression of p-GR and histone deacetylase-2 in the OVA + ozone group. STAT3 expression increased in the OVA + ozone group and could not be completely reversed by Dex, and nor could IL-6 expression. A positive correlation between IL-6 or IL-17A and STAT3 and negative correlation between SOCS3 and STAT3 were shown, suggesting that the IL-6/STAT3 pathway may be involved in OVA + ozone-induced corticosteroid-resistant airway inflammation. In clinical samples, IL-17A expression in lung tissue was positively correlated with percent STAT3-positive area and negatively correlated with SOCS3 expression. The IL-6/STAT3 pathway may contribute to corticosteroid insensitivity in OVA + ozone-induced neutrophilic airway inflammation through regulation of Th17 cells and could provide new targets for individual treatment of corticosteroid resistance in asthma.

7.
Expert Rev Mol Med ; 23: e16, 2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34758892

RESUMO

Cancer remains the leading cause of death worldwide, and metastasis is still the major cause of treatment failure for cancer patients. Epithelial-mesenchymal transition (EMT) has been shown to play a critical role in the metastasis cascade of epithelium-derived carcinoma. Tumour microenvironment (TME) refers to the local tissue environment in which tumour cells produce and live, including not only tumour cells themselves, but also fibroblasts, immune and inflammatory cells, glial cells and other cells around them, as well as intercellular stroma, micro vessels and infiltrated biomolecules from the nearby areas, which has been proved to widely participate in the occurrence and progress of cancer. Emerging and accumulating studies indicate that, on one hand, mesenchymal cells in TME can establish 'crosstalk' with tumour cells to regulate their EMT programme; on the other, EMT-tumour cells can create a favourable environment for their own growth via educating stromal cells. Recently, our group has conducted a series of studies on the interaction between tumour-associated macrophages (TAMs) and colorectal cancer (CRC) cells in TME, confirming that the interaction between TAMs and CRC cells mediated by cytokines or exosomes can jointly promote the metastasis of CRC by regulating the EMT process of tumour cells and the M2-type polarisation process of TAMs. Herein, we present an overview to describe the current knowledge about EMT in cancer, summarise the important role of TME in EMT, and provide an update on the mechanisms of TME-induced EMT in CRC, aiming to provide new ideas for understanding and resisting tumour metastasis.

8.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 43(5): 727-735, 2021 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-34728033

RESUMO

Objective To evaluate the influence of temperature on the outpatient visits for urticaria in Lanzhou City and its hysteresis and to find out the sensitive populations by sex and age stratification.Methods We collected the urticaria outpatient data in three grade A class three hospitals as well as the meteorological data and air pollutant data in Lanzhou from January 2011 to December 2017.The distributed lag non-linear model(DLNM)was employed to analyze the influence of daily mean temperature on the outpatient visits for urticaria.Stratification analysis was performed for different age groups(0-14,15-59,≥60 years)and different sex populations.Results Temperature had a non-linear relationship with the outpatient visits for urticaria,and there existed hysteresis.During the research period,the average daily outpatient visits for urticaria at the three hospitals in Lanzhou was 25,ranging from 1 to 76.With the rise in the daily mean temperature within 0-10 ℃,the risk of outpatient visits for urticaria first increased and then decreased.When the daily mean temperature was 2 ℃,hysteresis occurred on the 18th day,and the relative risk(RR)reached the maximum(1.12,95% CI:1.04-1.20)at the lag of 21 days.The risk of urticaria increased with the rise in temperature at high temperature.In addition,the effect of high temperature on the outpatient visits for urticaria in Lanzhou presented hysteresis,and the hysteresis was more obvious at higher temperatures.At the lag of 21 days,when the temperatures were 19.9 ℃ and 25.5 ℃,the RR values were 1.20(95% CI:1.12-1.27)and 1.39(95% CI:1.31-1.48),respectively.The results of stratified analysis showed that the effect of high temperature was more sensitive for those of 0-14 years and 15-59 years as well as the female population,and the RR values at a lag of 21 days were 1.60(95% CI:1.45-1.71),1.34(95% CI:1.25-1.43),and 1.43(95% CI:1.33-1.53)for the population of 0-14 years,the population of 15-59 years,and female population,respectively.Low temperature mainly affected the people aged ≥60 years,with a maximum RR of 1.38(95% CI:1.03-1.85)when the daily mean temperature was -4.8 ℃ at a lag of 12 days.It did not affect other populations.Conclusions The daily mean temperature in Lanzhou share a close relationship with the outpatient visits for urticaria.High temperature will increase the risk of urticaria for people at the age of 0-14 years and 15-59 years,while low temperature will increase the risk of urticaria for people above 60 years.


Assuntos
Poluentes Atmosféricos , Urticária , Adolescente , Poluentes Atmosféricos/análise , Criança , Pré-Escolar , China/epidemiologia , Feminino , Humanos , Lactente , Recém-Nascido , Pessoa de Meia-Idade , Dinâmica não Linear , Pacientes Ambulatoriais , Temperatura , Urticária/epidemiologia
9.
J Hazard Mater ; : 127703, 2021 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-34799159

RESUMO

Rice (Oryza sativa L.), a staple for half of the world's population, usually accumulates high levels of cadmium (Cd) in the grain when planted in the Cd-contaminated paddy fields. Genetic improvements using natural variation of grain-Cd accumulation is the most cost-effective way to mitigate the risk of excess Cd accumulation. However, as a complex trait, grain-Cd accumulation is susceptible to environmental variation, which challenges to characterize the genetic nature and subsequently the stable performance of grain-Cd accumulation. To boost the genetic effect on grain-Cd performance, we established an approach of normalization using the comparative grain-Cd value (CCd) following a contrasting field design. Identification of the genetic locus responsible for CCd variation help us develop a low-grain-Cd variety de novo, named 'Lushansimiao', which had lower grain-Cd levels in a large-scale field test and can produce Cd-safe rice following prolonged irrigations in the field with intermediate levels of Cd pollution. Combined CCd evaluating and low-Cd allelic genotyping, another six varieties were also identified as low-grain-Cd rice. Our study paves the way to efficiently quantify the genetic nature of grain-Cd accumulation in rice, and the stable low-Cd rice varieties will help to mitigate the risk of excess Cd accumulation in rice.

10.
Opt Express ; 29(23): 38849-38857, 2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34808928

RESUMO

Knots and links, as three-dimensional topologies, have played a fundamental role in many physical fields. Despite knotted vortex loops having been shown to exist in the light field, the three-dimensional configuration of vortex loop is fixed due to their topological robustness, making the fields with different topologies independent of each other. In this work, we established the mapping between the torus knots/links and the integer topological charge of the optical vortex, and demonstrated the change of the intermediate state with fractional charges. Furthermore, we experimentally observed the transformation process of the three-dimensional topological structure by only changing the topological charge. Remarkably, we revealed two different reconnection mechanisms associated with the odd or even index of the torus topology. We hope these results may provide new insight for the study of singular optics and evolution in other physical fields.

11.
Nat Commun ; 12(1): 6524, 2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34764284

RESUMO

Out-of-plane spin polarization σz has attracted increasing interests of researchers recently, due to its potential in high-density and low-power spintronic devices. Noncollinear antiferromagnet (AFM), which has unique 120° triangular spin configuration, has been discovered to possess σz. However, the physical origin of σz in noncollinear AFM is still not clear, and the external magnetic field-free switching of perpendicular magnetic layer using the corresponding σz has not been reported yet. Here, we use the cluster magnetic octupole in antiperovskite AFM Mn3SnN to demonstrate the generation of σz. σz is induced by the precession of carrier spins when currents flow through the cluster magnetic octupole, which also relies on the direction of the cluster magnetic octupole in conjunction with the applied current. With the aid of σz, current induced spin-orbit torque (SOT) switching of adjacent perpendicular ferromagnet is realized without external magnetic field. Our findings present a new perspective to the generation of out-of-plane spin polarizations via noncollinear AFM spin structure, and provide a potential path to realize ultrafast high-density applications.

12.
Oncol Res Treat ; 2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34775385

RESUMO

BACKGROUND: Breast cancer resistance protein (BCRP), or ABCG2 (ATP-binding cassette sub-family G member 2), is an ATP-binding cassette (ABC) transporter that mediates energy-dependent transport of substrate drugs out of the cell. Its overexpression may contribute to intrinsic drug resistance in vitro. However, the current literature has not yet clarified the clinical significance of BCRP/ABCG2 in invasive breast carcinoma. OBJECTIVES: The purpose of this study was to validate the expression of BCRP/ABCG2 in invasive breast carcinoma and its role in response to neoadjuvant chemotherapy. METHODS: In this study, a pretherapeutic core biopsy was performed in 222 patients. BCRP/ABCG2 expression in carcinoma tissue was measured by immunohistochemistry. BCRP/ABCG2 expression correlations with clinicopathological features, molecular subtypes, and therapy response after neoadjuvant chemotherapy were investigated. RESULTS: The results showed that BCRP/ABCG2 was expressed in different molecular subtypes. The proportions of patients with high BCRP/ABCG2 expression were similar in luminal A and luminal B tumors (Luminal B, 80%; Luminal A, 78%), compared with other molecular subtypes (Triple-negative, 63%; HER-2+, 58%. P=0.05). BCRP/ABCG2 expression and the number of lymphatic metastases (𝑃=0.001) and tumor size (𝑃=0.011) demonstrated a statistically significant correlation. Low BCRP/ABCG2 expression was associated with an increased pathological complete response (pCR) rate of 38%, higher than the 19% in tumors with high BCRP/ABCG2 expression (P=0.002). In multivariable analysis, BCRP/ABCG2 and hormone receptor (HR) expression were identified as independent risk factors of pCR (P=0.003, P=0.013. respectively). CONCLUSIONS: BCRP/ABCG2 is highly expressed in hormone receptor-positive breast cancer. High BCRP/ABCG2 expression is associated with lymphatic metastasis, tumor size, and poor pCR. BCRP/ABCG2 may be a novel potential biomarker that can predict clinical progression and therapy response after neoadjuvant chemotherapy.

13.
Clin Immunol ; 232: 108876, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34740840

RESUMO

PURPOSE: To evaluate the efficacy and safety of immune checkpoint inhibitor combination therapy in advanced renal cell carcinoma (RCC). METHODS: We searched PubMed/Embase/Cochrane Library for relevant randomized controlled trials (RCTs). Clinical outcome measures including overall survival (OS), progression-free survival (PFS), objective response rates (ORRs), and adverse events (AEs) were analyzed by Stata 15.1 software. RESULTS: Seven RCTs involving 3461 patients were included. The pooled hazard ratios of OS and PFS for combination therapy were 0.67 (0.53-0.82, p < 0.001) and 0.68 (0.52-0.83, p < 0.001), respectively. Longer OS and PFS for combination therapy was also observed in the PD-L1 expression leve ≥1% group. The pooled odds ratios of ORRs and grade 3 or higher AEs were 2.31 (1.61-3.32, p < 0.001) and 0.94 (0.65-1.37, p = 0.753), respectively. CONCLUSIONS: Immune checkpoint inhibitor combination therapy showed more clinical benefit in the first-line treatment for advanced RCC, with a safety profile.


Assuntos
Antineoplásicos Imunológicos/uso terapêutico , Carcinoma de Células Renais/tratamento farmacológico , Inibidores de Checkpoint Imunológico/uso terapêutico , Imunoterapia/métodos , Neoplasias Renais/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Humanos
14.
ACS Appl Mater Interfaces ; 13(46): 55600-55610, 2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34779615

RESUMO

The development of flexible and wearable electronic devices has put an increasing demand on electrode systems with seamless connection and high compatibility with the main device, in order to accommodate complex deformation conditions and maintain stable performance. Here, we present a carbon nanotube-integrated electrode (CNTIE) by wet-pulling the ends of a carbon nanotube (CNT) film to form condensed thin fibers that resemble conventional conducting wire electrodes. A flexible strain sensor was constructed consisting of the middle CNT film as the main functional part and the CNTIE as self-derived electrodes, with inherent CNT connection between the two parts. The sensor can be transferred to versatile substrates (e.g., balloon surface) or encapsulated in thermoplastic polymers, exhibiting a large linear response range (up to 1000% in tensile strain), excellent durability and repeatability over 5000 cycles, and the ability to detect small- to large-degree human body motions. In addition, the strain sensor based on the CNTIE hybrid film (MXene/CNT and graphene/CNT) also shows superior linearity and stability at a strain range of 0-800%. Compared with the sensors using traditional silver wire electrodes and separately fabricated CNT fiber electrodes, our CNTIE plays an important role in achieving highly stable performance in the strain cycles. Our self-derived integrated electrodes provide a potential route to solve the incompatibility issues of conventional electrodes and to develop high-performance flexible and wearable systems based on CNTs and other nanomaterials.

15.
Ecotoxicol Environ Saf ; 228: 112938, 2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34741930

RESUMO

Inhaling silica dust in the environment can cause progressive pulmonary fibrosis, then silicosis. Silicosis is the most harmful occupational disease in the world, so the study of the mechanism is of great significance for the prevention and treatment of silicosis. Long non-coding RNAs (lncRNAs) are important players in the pathological process of fibrotic diseases. However, the function of specific lncRNA in regulating pulmonary fibrosis remains elusive. In this study, a mouse model of pulmonary fibrosis via intratracheal instillation of silica particles was established, and the differential expression of lnc-SNHG1 and miR-326 in lung tissues and TGF-ß1-treated fibroblasts was detected by the qRT-PCR method. Short interfering RNA (siRNA) and plasmid were designed for knockdown or overexpression of lnc-SNHG1 in fibroblasts. MiRNA simulant was designed for overexpression of miR-326 in vivo and in vitro. Dual-luciferase reporter system, immunofluorescence, western blot, wound healing and transwell assay were performed to investigate the function and the underlying mechanisms of lnc-SNHG1. As a result, we found that lnc-SNHG1 was highly expressed in fibrotic lung tissues of mice and TGF-ß1-treated fibroblasts. Moreover, the high expression of lnc-SNHG1 facilitated the migration and invasion of fibroblasts and the secretion of fibrotic molecules, while the low expression of lnc-SNHG1 exerted the opposite effects. Further mechanism studies showed that miR-326 was the potential target of lnc-SNHG1, and there is a negative correlation between the expression levels of lnc-SNHG1 and miR-326. Combined with mitigating fibrotic effects of miR-326 in a mouse model of silica particles exposure, we revealed that lnc-SNHG1 significantly sponged miR-326 and facilitated the expression of SP1, thus accelerating fibroblast-to-myofibroblast transition and synergistically promoting the development of pulmonary fibrosis. Our study uncovered a key mechanism by which lnc-SNHG1 regulated pulmonary fibrosis through miR-326/SP1 axis, and lnc-SNHG1 is a potential target for the prevention and treatment of silicosis.

16.
Comput Intell Neurosci ; 2021: 5410440, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34630546

RESUMO

A synthetic aperture radar (SAR) target recognition method based on image blocking and matching is proposed. The test SAR image is first separated into four blocks, which are analyzed and matched separately. For each block, the monogenic signal is employed to describe its time-frequency distribution and local details with a feature vector. The sparse representation-based classification (SRC) is used to classify the four monogenic feature vectors and produce the reconstruction error vectors. Afterwards, a random weight matrix with a rich set of weight vectors is used to linearly fuse the feature vectors and all the results are analyzed in a statistical way. Finally, a decision value is designed based on the statistical analysis to determine the target label. The proposed method is tested on the moving and stationary target acquisition and recognition (MSTAR) dataset and the results confirm the validity of the proposed method.


Assuntos
Reconhecimento Automatizado de Padrão , Radar , Algoritmos
17.
Front Cardiovasc Med ; 8: 728746, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34604357

RESUMO

With the large-scale genome-wide sequencing, long non-coding RNAs (lncRNAs) have been found to compose of a large portion of the human transcriptome. Recent studies demonstrated the multidimensional functions of lncRNAs in heart development and disease. The subcellular localization of lncRNA is considered as a key factor that determines lncRNA function. Cytosolic lncRNAs mainly regulate mRNA stability, mRNA translation, miRNA processing and function, whereas nuclear lncRNAs epigenetically regulate chromatin remodeling, structure, and gene transcription. In this review, we summarize the molecular mechanisms of cytosolic and nuclear lncRNAs in heart development and disease separately, and emphasize the recent progress to dictate the crosstalk of cytosolic and nuclear lncRNAs in orchestrating the same biological process. Given the low evolutionary conservation of most lncRNAs, deeper understanding of human lncRNA will uncover a new layer of human regulatory mechanism underlying heart development and disease, and benefit the future clinical treatment for human heart disease.

18.
Appl Opt ; 60(23): 6843-6848, 2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34613164

RESUMO

In this paper, a compact and stable Q-switched erbium-doped fiber laser operating at around 1600 nm by employing a segment of 1-cm thulium-doped fiber saturable absorber (TDF-SA) is proposed. When the pump power is adjusted between 28 and 71 mW, the Q-switched operation can be maintained stably, and the output power increases from 74 µW to 2.6 mW. Furthermore, the peak power clamping effect is also observed when the pump power exceeds 60 mW. The structure of the cavity is greatly simplified by using all-optical and hybrid fiber components, which contributes to its long-term stability. Our results prove that the TDF can be a promising SA for all-fiber Q-switched pulses generation in the L-band.

19.
Opt Express ; 29(19): 29766-29779, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34614715

RESUMO

We demonstrate a prominent spatial frequency shift (SFS) for the femtosecond laser-induced periodic structures by only changing the polarization ellipticity of the working laser. The nanostructures are fabricated on the surfaces of silicon (Si) and zinc selenide (ZnSe) using elliptically polarized femtosecond laser pulses, with the pulse duration of 35 fs, the central wavelength of 800nm, and the repetition rate of 1kHz. The experimental results show that the red- and blue-shift trends of the SFS are individually represented on silicon and zinc selenide with the increased polarization ellipticity, where low- and high-spatial-frequency nano-ripples are fabricated, respectively. These unique phenomena are explained by using the laser-surface plasmon polariton interference mechanism and the effective medium theory. The proposed nanostructures with regulatable period are further used for creating nano-gratings on silicon which perform chirped characteristics.

20.
Opt Express ; 29(16): 25109-25117, 2021 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-34614849

RESUMO

We demonstrate a nanometric displacement sensor with a switchable measuring range by using a single silicon nanoantenna. It is revealed that the interference between the longitudinal and transverse dipolar scattering can be well tuned by moving the nanoantenna in the focal field of the cylindrical vector beam. As a result, a position related scattering directivity is found and is used as a displacement sensor with a 4.5 nm lateral resolution. Interestingly, the measuring range of this displacement sensor can be extended by twice through simply changing the excitation from the azimuthally polarized beam to the radially polarized beam. Our results provide a facile way to tune the measuring range of the nanometric displacement sensor and may open up an avenue to super-resolution microscopy and optical nanometrology.

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