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1.
J Agric Food Chem ; 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31895559

RESUMO

Facile fabrication of difunctional nanoparticles (NPs) for pesticide delivery and imaging is still a fascinating challenge. Here, water-dispersible difunctional NPs were developed using flash nanoprecipitation (FNP) where self-assembling amphiphilic block copolymers were used to encapsulate a highly hydrophobic model pesticide, Lambda-cyhalothrin, and the fluorescent dye Nile red. The particle size (ranging from 158 to 280 nm) and fluorescence property of NPs could be controlled by varying the flow rate or Nile red feed concentration. The aggregation state and rearrangement of the dye molecules in the NPs were also investigated. IVIS imaging and confocal laser scanning microscopy analysis demonstrated that the resulting difunctional nanopesticide particles could allow accurate in situ tracking of the pesticide on the leaf surface, while effectively avoiding interference from chlorophyll autofluorescence. The difunctional NP suspension maintained high insecticidal activity and stability. This work demonstrates the feasibility and great potential of the FNP method in universal fabrication of multifunctional NPs with in situ pesticide tracing and crop protection capabilities.

2.
J Diabetes Investig ; 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31912623

RESUMO

AIMS/INTRODUCTION: Diabetic nephropathy (DN) is a complication of diabetes mellitus that is characterized by the gradual loss of kidney function, which results in increased levels of albumin in the urine. The Pro12Ala polymorphism in peroxisome proliferator-activated receptorγ2 gene (PPARγ2) has been confirmed to improve insulin sensitivity, but its association with susceptibility to DN in patients with type 2 diabetes (T2DM) remains inconclusive. MATERIALS AND METHODS: To examine whether the Pro12Ala polymorphism leads to the development of DN, a case-control study was carried out in 554 patients with T2DM. The genotypes of Pro12Ala polymorphism of PPAR-γ2 gene were analyzed by real-time polymerase chain reaction with TaqMan® probe genotyping assay in all patients. RESULTS: The mean age of study population was 57.7 ± 8.8 years with average diabetes duration of 12.8 ± 6.9 years. The prevalence of albuminuria was 43.5%. The frequency of genotype Pro12Pro (PP), Pro12Ala (PA) and Ala12Ala (AA) genotype were 92.6%, 7.0%, 0.4% in our study population and 90.4%, 8.9%, 0.7% in normal urinary albumin-to-creatinine ratio (UACR) group, respectively. The Ala carriers (PA+AA) had significantly lower UACR (15.0 vs 20.5 mg/g, P=0.001) and better renal function (eGFR: 81.8[69.8-97.6] vs 78.7 mL/min/1.73 m2 [61.6-96.2]; p = 0.05) compared to those with the genotype PP. After adjustment for age, sex and other confounders, the odds ratio of albuminuria for the Ala12 allele was of 0.428 (95% CI: 0.195-0.940, p=0.034]). CONCLUSIONS: Our results suggest that the PPAR-γ2 Ala12 variant has significant protective effects against albuminuria and DN.

3.
J Transl Med ; 18(1): 12, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31915008

RESUMO

BACKGROUND: Malignant behavior and radioresistance, which severely limits the efficacy of radiation therapy (RT) in nasopharyngeal carcinoma (NPC), are associated with tumor progression and poor prognosis. Mesenchymal stem cells (MSCs) are used as a therapeutic tool in a variety of tumors. The aim of this study was to reveal the effect of tumor suppressor microRNA-34c-5p (miR-34c) on NPC development and radioresistance, as well as to confirm that exosomes derived from MSCs overexpressing miR-34c restore the sensitivity to radiotherapy in NPCs. METHODS: Potentially active microRNAs were screened by cell sequencing, Gene Expression Omnibus (GEO) database analysis, and analysis of clinical serum samples from 70 patients. The expression of genes and proteins was detected by Western blotting, quantitative reverse transcription PCR (qRT-PCR), and immunohistochemistry (IHC). Proliferation, apoptosis, invasion, migration and radioresistance of NPC were detected. Luciferase reporter assays were used to verify the interactions of microRNAs with their downstream targets. MSCs exosomes were isolated by ultrafiltration and verified by electron microscopy and nanoparticle tracking technology. RESULTS: The expression of miR-34c was associated with the occurrence and radiation resistance of NPC. In vitro and in vivo experiments indicated that overexpression of miR-34c inhibit malignant behavior such as invasion, migration, proliferation and epithelial-mesenchymal transition (EMT) in NPCs by targeting ß-Catenin. In addition, we found alleviated radioresistance upon miR-34c overexpression or ß-catenin knockdown in NPCs. Exosomes derived from miR-34c-transfected MSCs attenuated NPC invasion, migration, proliferation and EMT. Moreover, miR-34c-overexpressing exosomes drastically increased radiation-induced apoptosis in NPC cells. CONCLUSION: miR-34c is a tumor suppressor miR in NPC, which inhibits malignant behavior as well as radioresistance of tumor. Therefore, exogenous delivery of miR-34c to NPCs via MSC exosomes inhibits tumor progression and increases the efficiency of RT. Combination IR with miR-34c-overexpressing exosomes may be effective treatment for radioresistant NPCs.

4.
Langmuir ; 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31898907

RESUMO

Aqueous lubrication in nature is attracting increasing attention in the tribological fields for reducing friction energy consumption and improving anti-wear durability. Generally, adding nano lubricant additives is one of the most important strategies to effectively enhance the interface performance under boundary lubrication via the formation of a protective tribofilm on rubbing surfaces. However, the adsorbed tribofilms are unstable and prone to failure during friction, and the interaction mechanism between the tribofilms and frictional interfaces is partly disclosed. In this study, inspired by mussels, an in situ assembled polydopamine (PDA) tribofilm is achieved with PDA nanoparticles as aqueous lubricant additives, which shows excellent lubrication properties. The coefficient of friction is interface-independent and reduced by as much as 83%. The results show that the PDA tribofilm can not only form chemical bonding with metal interfaces but also present a synergistic lubrication effect with the upper ceramic surface. Especially, a self-repairing effect of the PAD tribofilm is observed, by which the ultra-stable lubricating properties can be achieved during friction, and thus the friction and wear can be effectively controlled. This work provides an effective method for improving the interface stability of friction pairs under aqueous lubrication, and also shows great meaning for industrial applications.

5.
Artif Cells Nanomed Biotechnol ; 48(1): 137-142, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31852310

RESUMO

Our previous study found that IL33 repressed the growth of pulmonary adenocarcinoma (PA) via regulation of dendritic cells (DCs). However, the molecular mechanism of DCs in PA is still unclear. The present work showed that CYLD-/- mice have a shorter survival rate of PA, and knockout CYLD in DCs also repress the progression of PA in mice. Subsequently, we found that decreased expression and reduced the nuclear translocation of NF-κB signalling was observed in CYLD knockout DCs, and inhibiting NF-κB pathway repressed DCs-induced proliferation and function of CD4+ T cells. These results indicated that CYLD function as a tumour suppresser in PA via regulates the function of DCs through NF-κB signalling pathway. Our findings support that CYLD serves as a potential target for immunotherapy in PA.

6.
Eur J Pharmacol ; 866: 172822, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31760068

RESUMO

Brown adipose tissue (BAT) plays important roles in regulating energy homeostasis and combating obesity. Accordingly, increasing the abundance and/or activating BAT would be effective and promising approaches to combat obesity and obesity-relative diseases. Our previous data in vitro have shown that osteopontin (OPN) induces the brown adipogenesis in 3T3-L1 cells via a phosphatidylinositol 3 kinase (PI3K)-AKT pathway. However, it is currently unknown whether OPN exerts such an effect on animals in vivo. Therefore, in the study we sought to investigate the pro-browning effects of OPN and to explore its underlying mechanisms by transfecting with Ad-GFP-aP2-OPN-shRNA to specifically down-regulate the OPN of white adipose tissue (WAT) in mice. Our present results show that downregulation of OPN in WAT exacerbates obesity and inhibits WAT-browning. Moreover, immunohistochemical results also exhibit that the downregulation of OPN significantly diminishes the expression and sub-cellular localization of UCP-1, PRDM16 and PGC-1α. Besides, the western blotting results reveal that the expression levels of PI3K, AKT-pS473 and PPARγ markedly reduce. Consequently, we conclude that the downregulation of OPN inhibits the browning of WAT through inhibiting the expression of PPARγ mediated by the PI3K-AKT pathway. The findings suggest that OPN is involved in regulation of WAT-browning and regulating its expression would become a potential strategy to combat obesity and obesity-relative metabolic diseases.

7.
Artigo em Inglês | MEDLINE | ID: mdl-31859476

RESUMO

Nonflammable solid-state electrolytes can potentially address the reliability and energy density limitations of lithium-ion batteries. Garnet-structured oxides such as Li7La3Zr2O12 (LLZO) are some of the most promising candidates for solid-state devices. Here, three-dimensional (3D) solid-state LLZO frameworks with low tortuosity pore channels are proposed as scaffolds, into which active materials and other components can be infiltrated to make composite electrodes for solid-state batteries. To make the scaffolds, we employed aqueous freeze tape casting (FTC), a scalable and environmentally friendly method to produce porous LLZO structures. Using synchrotron radiation hard X-ray microcomputed tomography, we confirmed that LLZO films with porosities of up to 75% were successfully fabricated from slurries with a relatively wide concentration range. The acicular pore size and shape at different depths of scaffolds were quantified by fitting the pore shapes with ellipses, determining the long and short axes and their ratios, and investigating the equivalent diameter distribution. The results show that relatively homogeneous pore sizes and shapes were sustained over a long range along the thickness of the scaffold. Additionally, these pores had low tortuosity and the wall thickness distributions were found to be highly homogeneous. These are desirable characteristics for 3D solid electrolytes for composite electrodes, in terms of both the ease of active material infiltration and also minimization of Li diffusion distances in electrodes. The advantages of the FTC scaffolds are demonstrated by the improved conductivity of LLZO scaffolds infiltrated with poly(ethylene oxide)/lithium bis(trifluoromethanesulfonyl)imide (PEO/LITFSI) compared to those of PEO/LiTFSI films alone or composites containing LLZO particles.

8.
Rice (N Y) ; 12(1): 88, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31792643

RESUMO

BACKGROUND: Soil salinity is one of the main environmental conditions that affects rice production. Identifying the genetic loci that affect rice salt tolerance (ST)-related traits at the seedling stage, especially under saline field conditions, is crucial for ST rice breeding by pyramiding ST genes that act at different developmental stages. RESULTS: Large phenotypic variations were observed in 708 rice accessions, and yield and its related traits were considerably limited when exposed to salt stress. In a genome-wide association study (GWAS), 2255 marker-trait association signals were detected for all measured traits, and the significant SNPs were distributed in 903 genes. Of these, 43 genes processed same functional annotation, and the gene ontology terms "biological processes" and "molecular function" with the known genes responsive to salt stress in rice. Further haplotype analysis detected 15 promising candidates significantly associated with the target traits, including five known genes and 10 novel genes. We identified seven accessions carrying favorable haplotypes of four genes significantly associated with grain yield that performed well under saline stress conditions. CONCLUSIONS: Using high density SNPs within genes to conduct GWAS is an effective way to identify candidate genes for salt tolerance in rice. Five known genes (OsMYB6, OsGAMYB, OsHKT1;4, OsCTR3, and OsSUT1) and two newly identified genes (LOC_Os02g49700, LOC_Os03g28300) significantly associated with grain yield and its related traits under saline stress conditions were identified. These promising candidates provide valuable resources for validating potential ST-related genes and will facilitate rice breeding for salt tolerance through marker-assisted selection.

9.
Front Pharmacol ; 10: 1344, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31824310

RESUMO

Osteoporosis is a bone disease characterized by increasing osseous fragility and fracture due to the reduced bone mass and microstructural degradation. Primary pharmacological strategies for the treatment of osteoporosis, hormone replacement treatment (HRT), and alendronate therapies may produce adverse side-effects and may not be recommended for long-term usage. Some classic and bone-specific natural Chinese medicine are very popularly used to treat osteoporosis and bone fracture effectively in clinical with their potential value in bone growth and development, but with few adverse side-effects. Current evidence suggests that the treatments appear to improve bone metabolism and attenuate the osteoporotic imbalance between bone formation and bone resorption at a cellular level by promoting osteoblast activity and inhibiting the effects of osteoclasts. The valuable therapies might, therefore, provide an effective and safer alternative to primary pharmacological strategies. Therefore, the purpose of this article is to comprehensively review these classic and bone-specific drugs in natural Chinese medicines for the treatment of osteoporosis that had been deeply and definitely studied and reported with both bone formation and antiresorption effects, including Gynochthodes officinalis (F.C.How) Razafim. & B.Bremer (syn. Morinda officinalis F.C.How), Curculigo orchioides Gaertn., Psoralea corylifolia (L.) Medik Eucommia ulmoides Oliv., Dipsacus inermis Wall. (syn. Dipsacus asperoides C.Y.Cheng & T.M.Ai), Cibotium barometz (L.) J. Sm., Velvet Antler, Cistanche deserticola Ma, Cuscuta chinensis Lam., Cnidium monnieri (L.) Cusson, Epimedium brevicornum Maxim, Pueraria montana (Lour.) Merr. and Salvia miltiorrhiza Bunge., thus providing evidence for the potential use of alternative Chinese medicine therapies to effectively treat osteoporosis.

10.
Nanoscale ; 2019 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-31829357

RESUMO

The metal-semiconductor heterostructure is an important candidate for photocatalysis due to its efficient charge transport and separation. A controllable morphology and ideal interfaces are critically significant for improving the heterostructure photocatalytic performance. By controlling the concentration of Cd2+ to control the reaction environment (pH value) and reaction rate, the CdSe nanocrystal is overgrown on the side or tip of the Au nanorods, which leads to a strong interaction between the excitons of CdSe nanocrystals and the plasmons of Au nanorods. Both kinds of Au-CdSe heterorods exhibit good hydrogen productivity. Particularly, the lateral Au-CdSe heterorods exhibit excellent photocatalytic efficiency due to the larger contact interface of Au and CdSe and the strong local field of the CdSe nanocrystals grown on one side of the Au nanorods being enhanced by the transverse plasmon resonance in the visible region. We provide an approach to modulate the combination of the asymmetric metal nanoparticle and the semiconductor shell; these core-semishell heterostructures have potential applications ranging from photocatalysis to photonic nanodevices.

11.
J Biomed Sci ; 26(1): 94, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31787098

RESUMO

BACKGROUND: Insulin-like growth factor 1 (IGF-1) is an important pleiotropic hormone that exerts neuroprotective and neuroreparative effects after a brain injury. However, the roles of IGF-1 variants in mild traumatic brain injury (mTBI) are not yet fully understood. This study attempted to elucidate the effects of IGF-1 variants on the risk and neuropsychiatric outcomes of mTBI. METHODS: Based on 176 recruited mTBI patients and 1517 control subjects from the Taiwan Biobank project, we first compared the genotypic distributions of IGF-1 variants between the two groups. Then, we analyzed associations of IGF-1 variants with neuropsychiatric symptoms after mTBI, including anxiety, depression, dizziness, and sleep disturbances. Functional annotation of IGF-1 variants was also performed through bioinformatics databases. RESULTS: The minor allele of rs7136446 was over-represented in mTBI patients compared to community-based control subjects. Patients carrying minor alleles of rs7136446 and rs972936 showed more dizziness and multiple neuropsychiatric symptoms after brain injury. CONCLUSIONS: IGF-1 variants were associated with the risk and neuropsychiatric symptoms of mTBI. The findings highlight the important role of IGF-1 in the susceptibility and clinical outcomes of mTBI.

12.
Artigo em Inglês | MEDLINE | ID: mdl-31791588

RESUMO

The microbiome is recognized as a quasi-organ in the human body. When dysbiosis of the microbiome occurs, this variation may contribute to alterations in the microenvironment, potentially inducing an inflammatory immune response and providing a niche for neoplastic growth. However, there is limited evidence regarding the correlation and interaction between the microbiome and tumorigenesis. By utilizing microRNA sequencing data of patients with colon and rectal cancer from The Cancer Genome Atlas, we designed a novel analytical process to extract non-human small RNA sequences and align them with the microbial genome to obtain a comprehensive view of the cancer-associated microbiome. In the present study, we identified >1000 genera among 630 colorectal samples and clustered these samples into three distinctive colorectal enterotypes. Furthermore, we found 12 genera from these clusters that are associated with cancer stages and revealed their putative functions. Our results indicate that the proposed analytical approach can effectively determine the cancer-associated microbiome. It may be readily applied to explore other types of cancer, in which specimens of the microbiome are difficult to collect.

13.
J Card Surg ; 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31794109

RESUMO

BACKGROUND: Patient-prosthesis mismatch (PPM) has been shown to be associated with adverse outcomes after surgical aortic valve replacement. There is limited data on its risk and impact after transcatheter aortic valve replacement (TAVR), especially with the newer generation heart valves. OBJECTIVES: The objective of this study is to investigate the incidence, predictors, and clinical outcomes of PPM after TAVR. METHODS: This is a retrospective study of 991 consecutive patients who underwent TAVR procedure at a tertiary referral center, between April 2012 and February 2019. Patients were stratified by the presence or absence of PPM, defined as an effective orifice area/body surface area ratio ≤0.85 cm2 /m2 . Multivariable logistic regression analysis was used to determine independent predictors of PPM. Kaplan-Meier survival estimates were used to determine overall 5-year survival. RESULTS: PPM was encountered in 27.6% of patients. In multivariable analysis, age less than 70 years (P = .062), body mass index (BMI) more than 30 (P = .0057), history of atrial fibrillation (P = .0004), black race (P = .0078), and Sapien 3 sizes 20 and 23 mm (P < .0001)emerged as independent predictors of PPM. Sapien 3 valve size 20/23 mm was associated with higher risk of PPM compared to other valve types. Patients with PPM had comparable postoperative outcomes and overall 5-year survival. There was no significant difference in postoperative complications between patient groups. PPM was not associated with worse overall survival (56% for both PPM and no-PPM patients, log-rank P = .80). CONCLUSIONS: Younger age, atrial fibrillation, black race, higher BMI were predictors of PPM. Smaller sizes balloon-expandable valves had a higher risk of PPM.

15.
Chemistry ; 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31803978

RESUMO

Metal-organic rotaxane frameworks (MORFs) attracted much attention in the past years for construction of intelligent functional materials. Herein, we report one-pot synthesis of a three-dimensional (3D) cucurbit[7]uril (Q[7])-based MORF under hydrothermal conditions, namely Q[7]-MORF-1, formed by encapsulating the anionic benzoate moieties of the tricarboxylate ligand into the cavity of Q[7]. Furthermore, Q[7]-MORF-1 shows dual-capture capacity for iodine and K+ selectively among the alkali metal ions. The captured molecular iodine is included in the cavity of Q[7] via halogen-bonding interactions and the K+ cations are positioned at the carbonyl port of the Q[7] through K-O coordination interactions.

16.
Ann Transl Med ; 7(20): 536, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31807518

RESUMO

Background: Male breast cancer (MBC) is a rare malignancy. We aimed to analyze the incidence trends, clinicopathological characteristics, and survival outcomes in early MBC comparison with early female breast cancer (FBC). Methods: We included eligible MBC and FBC patients with stage I-II disease in the Surveillance, Epidemiology, and End Results (SEER) database from 2000-2015. Joinpoint regression was used to evaluate the trends in age-adjusted incidence. A one-to-four propensity score matching (PSM) analysis was performed to reduce bias in a retrospective study. Survival outcomes were evaluated using Kaplan-Meier analyses with the log-rank test and Cox proportional hazards regression analysis. Results: Trends in the age-adjusted incidence rates of early MBC were stable [2000-2015, annual percentage change (APC) =0.50, 95% confidence interval (CI): -0.1 to 1.1, P=0.102]; however, the incidence of early FBC changed significantly over the time period (2000-2015, APC = 0.30, 95% CI: 0.0 to 0.6, P=0.045). In the matched cohort, unmarried status, higher grade, larger tumor size, and advanced lymph node (LN) status were associated with a higher risk of breast cancer death and death of any causes both in early MBC and FBC patients. The hormone receptor (HR) status was as a prognostic factor in FBC patients, but not in MBC. Early MBC had worse breast cancer-specific survival (BCSS) and overall survival (OS) than early FBC in stage I, stage II and HR-positive subgroup of patients. Conclusions: The biological behavior, clinicopathological features, and clinical outcomes of early MBC are different from that of FBC. Further studies on individualized treatment approaches in MBC are needed.

17.
Cell Cycle ; : 1-11, 2019 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-31814518

RESUMO

Small nucleolar RNA host gene 7 (SNHG7) is a newly recognized oncogenic Long non-coding RNA (lncRNA) in most human cancers. In gastric cancer, SNHG7 has been suggested to enhance cell proliferation and suppressed apoptosis through down-regulating P15 and P16 expression, but the effect of SNHG7 on gastric cancer cell migration and invasion was still unknown. In our study, we aimed to estimate the relationship between SNHG7 expression and clinical and pathological characteristics, and explore the effect of SNHG7 on gastric cancer cell migration and invasion. In our study, the levels of SNHG7 expression in gastric cancer tissues and cell lines were severally higher than in normal adjacent tissues and gastric mucosal epithelial cells. Moreover, high SNHG7 expression was positively correlated with TNM stage, depth of invasion, lymph-node metastasis and distant metastasis in gastric cancer patients. Furthermore, the multivariate Cox proportional hazard analysis further showed high SNHG7 expression was an independent poor prognostic factor for overall survival in gastric cancer patients. The studies in vitro revealed that SNHG7 directly binds to miR-34a and negatively regulates miR-34a expression, and SNHG7 enhances gastric cancer cell migration and invasion through suppressing miR-34a-Snail-EMT axis. In conclusion, SNHG7 functions as oncogenic lncRNA in gastric cancer and may be a potential therapeutic target for gastric cancer patients.Abbreviations: lncRNA: Long non-coding RNA; SNHG7: Small nucleolar RNA host gene 7; EMT: Epithelial mesenchymal transition; TNM: Tumor-Lymph Node-Metastasis.

18.
J Vis Exp ; (153)2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31814625

RESUMO

Stem cell-based therapies for brain injuries, such as traumatic brain injury (TBI), are a promising approach for clinical trials. However, technical hurdles such as invasive cell delivery and tracking with low transplantation efficiency remain challenges in translational stem-based therapy. This article describes an emerging technique for stem cell labeling and tracking based on the labeling of the mesenchymal stem cells (MSCs) with superparamagnetic iron oxide (SPIO) nanoparticles, as well as intranasal delivery of the labeled MSCs. These nanoparticles are fluorescein isothiocyanate (FITC)-embedded and safe to label the MSCs, which are subsequently delivered to the brains of TBI-induced mice by the intranasal route. They are then tracked non-invasively in vivo by real-time magnetic resonance imaging (MRI). Important advantages of this technique that combines SPIO for cell labeling and intranasal delivery include (1) non-invasive, in vivo MSC tracking after delivery for long tracking periods, (2) the possibility of multiple dosing regimens due to the non-invasive route of MSC delivery, and (3) possible applications to humans, owing to the safety of SPIO, non-invasive nature of the cell-tracking method by MRI, and route of administration.

19.
ACS Nano ; 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31841297

RESUMO

Optical excitation, subsequent energy transfer, and emission are fundamental to many physical problems. Optical antennas are ideal candidates for manipulating these processes. We extend energy transfer to second- and third-harmonic (SH and TH) fields through the collaborative susceptibility χ(n) (n = 1, 2, 3) resonances of nonlinear optical antennas. Hollow gold stars, with a broadband response covering the fundamental, SH, and TH frequencies, are synthesized as nonlinear antennas. Harmonic resonance energy transfer through a χ(3) → χ(1) collaboration is revealed. A χ(3) → χ(2) collaboration is uncovered, with largely enhanced SH radiation demonstrated by exciting the three resonances at the fundamental, SH, and TH frequencies. A theoretical model of the effective nonlinear susceptibilities is proposed to calculate the efficiencies of the two nonlinear energy transfer processes.

20.
Artigo em Inglês | MEDLINE | ID: mdl-31861736

RESUMO

: Purpose: To improve numerical simulation of the non-contact tonometry test by using arbitrary Lagrangian-Eulerian deforming mesh in the coupling between computational fluid dynamics model of an air jet and finite element model of the human eye. METHODS: Computational fluid dynamics model simulated impingement of the air puff and employed Spallart-Allmaras model to capture turbulence of the air jet. The time span of the jet was 30 ms and maximum Reynolds number was Re=2.3×104, with jet orifice diameter 2.4 mm and impinging distance 11 mm. The model of the human eye was analysed using finite element method with regional hyperelastic material variation and corneal patient-specific topography starting from stress-free configuration. The cornea was free to deform as a response to the air puff using an adaptive deforming mesh at every time step of the solution. Aqueous and vitreous humours were simulated as a fluid cavity filled with incompressible fluid with a density of 1000 kg/m3. RESULTS: Using the adaptive deforming mesh in numerical simulation of the air puff test improved the traditional understanding of how pressure distribution on cornea changes with time of the test. There was a mean decrease in maximum pressure (at corneal apex) of 6.29 ± 2.2% and a development of negative pressure on a peripheral corneal region 2-4 mm away from cornea centre. CONCLUSIONS: The study presented an improvement of numerical simulation of the air puff test, which will lead to more accurate intraocular pressure (IOP) and corneal material behaviour estimation. The parametric study showed that pressure of the air puff is different from one model to another, value-wise and distribution-wise, based on cornea biomechanical parameters.

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