Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Ethnopharmacol ; 319(Pt 3): 117365, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38380568

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Fufangxiaopi Formula (FF) is a modified form of Sishen Wan, traditionally used for treating diarrhea. The application of FF for treating ulcerative colitis (UC) has achieved desirable outcomes in clinical settings. However, the underlying mechanism of the effect of FF on UC is yet to be determined. AIM OF STUDY: This study aimed to evaluate the protective effect and underlying mechanism of FF on mice with dextran sodium sulfate (DSS)-induced colitis. MATERIALS AND METHODS: In vivo, the efficacy of FF on the symptoms associated with DSS-induced colitis in mice was clarified by observing the body weight change, colon length, DAI score, and H&E staining. The release of inflammatory mediators in mouse colon tissues was detected by ELISA and MPO, and the contents of TLR4/NF-κB signaling pathway and MAPK signaling pathway-related proteins, as well as intestinal barrier-related proteins, were detected in mouse colon tissues by western blot method. Changes in the content of barrier proteins in mouse colon tissues were detected by immunofluorescence. 16S rRNA sequencing and FMT were performed to clarify the effects of FF on intestinal flora. In vitro, the effect of FF-containing serum on LPS-induced inflammatory mediator release from RAW264.7 cells were detected by qRT-PCR. The contents of TLR4/NF The effects of FF-containing serum on B signaling pathway and MAPK signaling pathway related proteins in RAW264.7 cells and intestinal barrier related proteins in Caco-2 cells were detected by western blot. The effects of FF-containing serum on LPS-induced nuclear translocation of p65 protein in RAW264.7 cells and barrier-associated protein in Caco-2 cells were detected by immunofluorescence. RESULTS: In vivo studies showed that FF could significantly alleviate the symptoms of UC, including reducing colon length, weight loss, clinical score, and colon tissue injury in mice. FF could significantly reduce the secretion of proinflammatory cytokines by suppressing the activation of the TLR4/NF-κB and MAPK signaling pathways. Moreover, FF could protect the integrity of intestinal barriers by significantly increasing claudin-3, occludin, and ZO-1 expression levels. 16S rRNA sequencing and FMT elucidate that FF can alleviate symptoms associated with colitis in mice by interfering with intestinal flora. In vitro studies showed that FF drug-containing serum could significantly inhibit proinflammatory responses and attenuate the secretion of iNOS, IL-1ß, TNF-α, IL-6, and COX-2 by suppressing the activation of TLR4/NF-κB and MAPK signaling pathways in RAW264.7 cells. Furthermore, FF could protect the Caco-2 cell epithelial barrier. CONCLUSION: FF could alleviate DSS-induced colitis in mice by maintaining the intestinal barrier, inhibiting the activation of TLR4/NF-κB and MAPK signaling pathways, reducing the release of proinflammatory factors, and regulating intestinal microecology.


Assuntos
Colite Ulcerativa , Colite , Humanos , Camundongos , Animais , NF-kappa B/metabolismo , RNA Ribossômico 16S , Receptor 4 Toll-Like/metabolismo , Lipopolissacarídeos/farmacologia , Células CACO-2 , Colite/induzido quimicamente , Colite/tratamento farmacológico , Colite Ulcerativa/induzido quimicamente , Colite Ulcerativa/tratamento farmacológico , Inflamação/tratamento farmacológico , Colo , Sulfato de Dextrana , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças
2.
Phytother Res ; 38(4): 2023-2040, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38384110

RESUMO

Ulcerative colitis (UC) is one of the most prevalent inflammatory bowel diseases and poses a serious threat to human health. Currently, safe and effective preventive measures are unavailable. In this study, the protective effects of asiaticoside (AS) on dextran sodium sulfate (DSS)-induced colitis in mice and the underlying molecular mechanism were investigated. In this experiment, colitis was induced in mice with DSS. Subsequently, the role of AS in colitis and its underlying mechanisms were examined using H&E staining, immunofluorescence staining, western blot, Elisa, FMT, and other assays. The results showed that AS significantly attenuated the related symptoms of DSS-induced colitis in mice. In addition, AS inhibited the activation of signaling pathways TLR4/NF-κB and MAPK reduced the release of inflammatory factors, thereby attenuating the inflammatory response in mice. AS administration also restored the permeability of the intestinal barrier by increasing the levels of tight junction-associated proteins (claudin-3, occludin, and ZO-1). In addition, AS rebalanced the intestinal flora of DSS-treated mice by increasing the diversity of the flora. AS can alleviate DSS-induced ulcerative colitis in mice by maintaining the intestinal barrier, thus inhibiting the signaling pathways TLR4/NF-κB and MAPK activation, reducing the release of inflammatory factors, and regulating intestinal microecology.


Assuntos
Colite Ulcerativa , Colite , Triterpenos , Humanos , Animais , Camundongos , Colite Ulcerativa/induzido quimicamente , Colite Ulcerativa/tratamento farmacológico , NF-kappa B , Receptor 4 Toll-Like , Colite/induzido quimicamente , Colite/tratamento farmacológico , Sulfato de Dextrana/efeitos adversos , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças , Colo
3.
Phytomedicine ; 116: 154891, 2023 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-37229891

RESUMO

BACKGROUND: Vascular remodeling plays a crucial role in the pathogenesis of several cardiovascular diseases (CVDs). Unfortunately, current drug therapies offer limited relief for vascular remodeling. Therefore, the development of innovative therapeutic strategies or drugs that target vascular remodeling is imperative. Betulinaldehyde (BA) is a triterpenoid with diverse biological activities, but its effects on vascular remodeling remain unclear. OBJECTIVE: This study aimed to investigate the role of BA in vascular remodeling and its mechanism of action, providing valuable information for future applications of BA in the treatment of CVDs. METHODS: Network pharmacology was used to predict the key targets of BA in vascular remodeling. The effect of BA on vascular remodeling was assessed in a rat model of balloon injury using hematoxylin and eosin staining, Masson staining, immunohistochemistry staining, and Western blotting. A phenotypic transformation model of vascular smooth muscle cells (VSMCs) was induced by platelet-derived growth factor-BB, and the functional impacts of BA on VSMCs were assessed via CCK-8, EdU, Wound healing, Transwell, and Western blotting. Finally, after manipulation of phospholipase C gamma1 (PLCγ1) expression, Western blotting and Ca2+ levels determination were performed to investigate the potential mechanism of action of BA. RESULTS: The most key target of BA in vascular remodeling, matrix metalloproteinase 9 (MMP9), was identified through network pharmacology screening. Vascular remodeling was alleviated by BA in vivo and its effects were associated with decreased MMP9 expression. In vitro studies indicated that BA inhibited VSMC proliferation, migration, phenotypic transformation, and downregulated MMP9 expression. Additionally, BA decreased PLCγ1 expression and Ca2+ levels in VSMCs. However, after pretreatment with a phospholipase C agonist, BA's effects on down-regulating the expression of PLCγ1 and Ca2+ levels were inhibited, while the expression of MMP9 increased compared to that in the BA treatment group. CONCLUSION: This study demonstrated the critical role of BA in vascular remodeling. These findings revealed a novel mechanism whereby BA mediates its protective effects through MMP9 regulation by inhibiting the PLCγ1/Ca2+/MMP9 signaling pathway. Overall, BA may potentially be developed into a novel medication for CVDs and may serve as a promising therapeutic strategy for improving recovery from CVDs by targeting MMP9.


Assuntos
Metaloproteinase 9 da Matriz , Remodelação Vascular , Ratos , Animais , Proliferação de Células , Metaloproteinase 9 da Matriz/metabolismo , Fosfolipase C gama/metabolismo , Becaplermina , Miócitos de Músculo Liso , Movimento Celular , Células Cultivadas
4.
Artigo em Inglês | MEDLINE | ID: mdl-36673979

RESUMO

Soil erosion is an important global environmental issue that severely affects regional ecological environment and socio-economic development. The Yellow River (YR) is China's second largest river and the fifth largest one worldwide. Its watershed is key to China's economic growth and environmental security. In this study, six impact factors, including rainfall erosivity (R), soil erosivity (K), slope length (L), slope steepness (S), cover management (C), and protective measures (P), were used. Based on the revised universal soil loss equation (RUSLE) model, and combined with a geographic information system (GIS), the temporal and spatial distribution of soil erosion (SE) in the YR from 2000 to 2020 was estimated. The patch-generating land use simulation (PLUS) model was used to simulate the land-use and land-cover change (LUCC) under two scenarios (natural development and ecological protection) in 2040; the RUSLE factor P was found to be associated with LUCC in 2040, and soil erosion in the Yellow River Basin (YRB) in 2040 under the two scenarios were predicted and evaluated. This method has great advantages in land-use simulation, but soil erosion is greatly affected by rainfall and slope, and it only focuses on the link between land-usage alteration and SE. Therefore, this method has certain limitations in assessing soil erosion by simulating and predicting land-use change. We found that there is generally slight soil erosivity in the YRB, with the most serious soil erosion occurring in 2000. Areas with serious SE are predominantly situated in the upper reaches (URs), followed by the middle reaches (MRs), and soil erosion is less severe in the lower reaches. Soil erosion in the YRB decreased 11.92% from 2000 to 2020; thus, soil erosion has gradually reduced in this area over time. Based on the GIS statistics, land-use change strongly influences SE, while an increase in woodland area has an important positive effect in reducing soil erosion. By predicting land-use changes in 2040, compared to the natural development scenario, woodland and grassland under the ecological protection scenario can be increased by 1978 km2 and 2407 km2, respectively. Soil erosion can be decreased by 6.24%, indicating the implementation of woodland and grassland protection will help reduce soil erosion. Policies such as forest protection and grassland restoration should be further developed and implemented on the MRs and URs of the YR. Our research results possess important trend-setting significance for soil erosion control protocols and ecological environmental protection in other large river basins worldwide.


Assuntos
Rios , Solo , Erosão do Solo , Modelos Teóricos , Monitoramento Ambiental/métodos , Conservação dos Recursos Naturais
5.
Molecules ; 27(24)2022 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-36557939

RESUMO

Colorectal cancer (CRC) is a prevalent and serious gastrointestinal malignancy with high mortality and morbidity. Chemoprevention refers to a newly emerged strategy that uses drugs with chemopreventive properties to promote antioxidation, regulate cancer cell cycle, suppress proliferation, and induce cellular apoptosis, so as to improve cancer treatment outcomes. Natural polyphenols are currently recognized as a class of chemopreventive agents that have shown remarkable anticarcinogenic properties. Numerous in vitro and in vivo studies have elucidated the anti-CRC mechanisms of natural polyphenols, such as regulation of various molecular and signaling pathways. Natural polyphenols are also reportedly capable of modulating the gut microbiota and cancer stem cells (CSCs) to suppress tumor formation and progression. Combined use of different natural polyphenols is recommended due to their low bioavailability and instability, and combination treatment can exert synergistical effects, reduce side effects, and avoid drug resistance in CRC treatment. In summary, the application of polyphenols in the chemoprevention and treatment of CRC is promising. Further clinical evaluation of their effectiveness is warranted and anticipated.


Assuntos
Anticarcinógenos , Neoplasias Colorretais , Humanos , Polifenóis/farmacologia , Polifenóis/uso terapêutico , Anticarcinógenos/farmacologia , Quimioprevenção , Transdução de Sinais , Neoplasias Colorretais/patologia
6.
Mol Med Rep ; 25(2)2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34958106

RESUMO

The natural incidence of primary epithelial ovarian cancer (OVC) in adult female voles of some established strains of Microtus fortis is relatively high. M. fortis OVC has some pathological similarities to human epithelial OVC, therefore M. fortis represents the latest and most valuable animal model for studying human OVC. The lack of available genetic information for M. fortis limits the use of common immunological methods; thus, high­throughput sequencing technologies have been used to reveal the mechanisms of primary OVC in M. fortis. The individuals with cancer were diagnosed using histopathologic hematoxylin and eosin staining. The present study used RNA­sequencing (RNA­seq) technology to establish a de novo assembly of the M. fortis transcriptome produced 339,830 unigenes by the short reads assembly program Trinity. Comparisons were made between OVC and healthy ovarian tissue (OV) and between fallopian tube cancer (FTC) and healthy fallopian tube (FT) tissues using RNA­seq analysis. A total of 3,434 differentially expressed genes (DEGs) were identified in OVC tissue compared with OV tissue using RNA­Seq by Expectation­Maximization software, including 1,950 significantly upregulated and 1,484 significantly downregulated genes. There were 2,817 DEGs identified in the FTC tissues compared with the FT tissue, including 1,762 significantly upregulated and 1,055 significantly downregulated genes. Pathway enrichment analysis revealed that upregulated transcripts in the OVC vs. OV groups were involved in cell growth and proliferation­associated pathways, whereas the downregulated DEGS in the OVC vs. OV groups were enriched in steroid biosynthesis­related pathways. Furthermore, the tumor suppressor gene, p53, was downregulated in the FTC and OVC compared with the FT and OV groups, respectively; whereas, genes that promoted cell migration, such as Ras­related protein Rap­1b, Ras homolog family member A and RAC1, were upregulated. In summary, to the best of our knowledge, the present study characterized the M. fortis de novo transcriptome of OV and FT tissues and to perform RNA­seq quantification to analyze the differences in healthy and cancerous OV and FT tissues. These results identified pathways that differed between cancerous and healthy M. fortis tissues. Analysis of these pathways may help to reveal the pathogenesis of primary OVC in M. fortis in future work.


Assuntos
Arvicolinae/genética , Arvicolinae/metabolismo , Carcinoma Epitelial do Ovário/genética , Carcinoma Epitelial do Ovário/metabolismo , Transcriptoma/genética , Animais , Carcinoma Epitelial do Ovário/patologia , Neoplasias das Tubas Uterinas/genética , Neoplasias das Tubas Uterinas/metabolismo , Feminino , Regulação Neoplásica da Expressão Gênica , Análise de Sequência de RNA
7.
Ann Transl Med ; 10(24): 1394, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36660694

RESUMO

Background: In the era of precision therapy, early classification of breast cancer (BRCA) molecular subtypes has clinical significance for disease management and prognosis. We explored the accuracy of machine learning (ML) models for early classification of BRCA molecular subtypes through a systematic review of the literature currently available. Methods: We retrieved relevant studies published in PubMed, EMBASE, Cochrane, and Web of Science until 15 April 2022. A prediction model risk of bias assessment tool (PROBAST) was applied for the assessment of risk of bias of a genomics-based ML model, and the Radiomics Quality Score (RQS) was simultaneously used to evaluate the quality of this radiomics-based ML model. A random effects model was adopted to analyze the predictive accuracy of genomics-based ML and radiomics-based ML for Luminal A, Luminal B, Basal-like or triple-negative breast cancer (TNBC), and human epidermal growth factor receptor 2 (HER2). The PROSPERO of our study was prospectively registered (CRD42022333611). Results: Of the 38 studies were selected for analysis, 14 ML models were based on gene-transcriptomic, with only 4 external validations; and 43 ML models were based on radiomics, with only 14 external validations. Meta-analysis results showed that c-statistic values of the ML based on radiomics for the identification of BRCA molecular subtypes Luminal A, Luminal B, Basal-like or TNBC, and HER2 were 0.76 [95% confidence interval (CI): 0.60-0.96], 0.78 (95% CI: 0.69-0.87), 0.89 (95% CI: 0.83-0.91), and 0.83 (95% CI: 0.81-0.86), respectively. The c-statistic values of ML based on the gene-transcriptomic analysis cohort for the identification of the previously described BRCA molecular subtypes were 0.96 (95% CI: 0.93-0.99), 0.96 (95% CI: 0.93-0.99), 0.98 (95% CI: 0.95-1.00), and 0.97 (95% CI: 0.96-0.98) respectively. Additionally, the sensitivity of the ML model based on radiomics for each molecular subtype ranged from 0.79 to 0.85, while the sensitivity of the ML model based on gene-transcriptomic was between 0.92 and 0.99. Conclusions: Both radiomics and gene transcriptomics produced ideal effects on BRCA molecular subtype prediction. Compared with radiomics, gene transcriptomics yielded better prediction results, but radiomics was simpler and more convenient from a clinical point of view.

8.
Nat Microbiol ; 6(1): 51-58, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33199863

RESUMO

Coronavirus disease 2019 (COVID-19) is caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)1-3 and individuals with COVID-19 have symptoms that can be asymptomatic, mild, moderate or severe4,5. In the early phase of infection, T- and B-cell counts are substantially decreased6,7; however, IgM8-11 and IgG12-14 are detectable within 14 d after symptom onset. In COVID-19-convalescent individuals, spike-specific neutralizing antibodies are variable3,15,16. No specific drug or vaccine is available for COVID-19 at the time of writing; however, patients benefit from treatment with serum from COVID-19-convalescent individuals17,18. Nevertheless, antibody responses and cross-reactivity with other coronaviruses in COVID-19-convalescent individuals are largely unknown. Here, we show that the majority of COVID-19-convalescent individuals maintained SARS-CoV-2 spike S1- and S2-specific antibodies with neutralizing activity against the SARS-CoV-2 pseudotyped virus, and that some of the antibodies cross-neutralized SARS-CoV, Middle East respiratory syndrome coronavirus or both pseudotyped viruses. Convalescent individuals who experienced severe COVID-19 showed higher neutralizing antibody titres, a faster increase in lymphocyte counts and a higher frequency of CXCR3+ T follicular help (TFH) cells compared with COVID-19-convalescent individuals who experienced non-severe disease. Circulating TFH cells were spike specific and functional, and the frequencies of CXCR3+ TFH cells were positively associated with neutralizing antibody titres in COVID-19-convalescent individuals. No individuals had detectable autoantibodies. These findings provide insights into neutralizing antibody responses in COVID-19-convalescent individuals and facilitate the treatment and vaccine development for SARS-CoV-2 infection.


Assuntos
Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , COVID-19/imunologia , SARS-CoV-2/imunologia , Células T Auxiliares Foliculares/imunologia , Anticorpos Neutralizantes/imunologia , Reações Cruzadas , Humanos , Receptores CXCR3/imunologia
9.
J Anal Methods Chem ; 2020: 8548126, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32399312

RESUMO

Sedimentary phosphorus (P) forms are important representatives of P sources and their bioavailability as well as the potential of sediments to release P in water. In this study, surface sediments along a transect of the Changjiang Estuary and two transects along the Andong salt marsh in the southwest of Hangzhou Bay were subjected to the elucidation of sedimentary P species using the standards, measurements, and testing (SMT) and sequential extraction (SEDEX) methods. The results showed that the mean sedimentary P forms elucidated by the SMT method were as follows: organic P (OP; ∼11-14 mg/kg; ∼30-45% of total P; TP) > apatite P (∼5-15 mg/kg; ∼21-36% TP) > Fe/Al-P (∼8-14 mg/kg; ∼31-34% TP), with inorganic P (IP) composing 54-70% of TP. The mean sedimentary P forms elucidated by the SEDEX method were as follows: authigenic P (∼54-68 mg/kg; ∼41-46% TP) > extractable P (Ex-P; ∼36-53 mg/kg; ∼28-34%) > Fe-P (∼21-27 mg/kg; ∼13-19%) > OP (∼8.7-13 mg/kg; ∼5-8%) > detrital P (De-P; ∼2 mg/kg; ∼1-2% TP), with IP composed of ∼91-94% TP. These results showed that the SEDEX method elucidated higher concentrations of sedimentary P forms as well as the TP from these coastal sediments although the SMT method had the advantage of being more economic and faster. The results of both the SMT and SEDEX methods showed that the Andong salt marsh and Changjiang Estuary sediments had much bioavailable P. The mean percentages of bioavailable P from the SMT and SEDEX methods were ∼64-74% and 52-56% of TP, respectively, indicating that these sediments were prone to release P to the coastal areas.

10.
Appl Opt ; 58(16): 4458-4466, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31251256

RESUMO

This paper investigated the use of spectra and multispectral images for on-site visualized classification of transparent hazards and noxious substances (HNS), such as benzene, xylene, and palm oil, floating on a water surface with the potential use for rapid classification of multiple HNS during a leak accident. Partial least-squares discrimination analysis (PLS-DA) and least-squares support vector machine (LS-SVM) models achieved a classification accuracy of 100% for spectral reflectance (325-900 nm) and multispectral image at nine wavelengths. Wavelength division and selection were applied for spectra and spectral images, respectively, to reduce the difficulty in data collection and to simplify the redundant bands. This was followed by PLS-DA and LS-SVM modeling. The LS-SVM model based on the least wavelengths (365, 410, 450, and 850 nm) of multispectral images was suggested as the most effective method for on-site visualized classification of transparent HNS on a water surface.

11.
Anal Chem ; 91(1): 1056-1063, 2019 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-30539637

RESUMO

The ability to detect cancer early in an accurate and rapid fashion is of critical importance for cancer diagnosis and accurate resection in surgery. γ-Glutamyltranspeptidase (GGT) is overexpressed in several human cancers, while maintaining a low expression in normal microenvironments, and thus is recognized as an important cancer biomarker. To date, rational design of a zero cross-talk ratiometric near-infrared (NIR) GGT fluorescent probe for efficient cancer diagnosis in various biological samples is still a big challenge. In this work, a zero cross-talk ratiometric NIR GGT fluorescent probe named Cy-GSH is developed. Cy-GSH shows high sensitivity to GGT, which is desired for early cancer diagnosis. Upon additional GGT, a large emission shift from 805 to 640 nm is observed, which is suitable for visualizing deeply located cancer in vivo. In addition, successful monitoring of GGT activity in blood, cells, tissues, and in vivo makes Cy-GSH possess great potential for the clinical cancer early diagnosis. Furthermore, accurately visualizing tumors and metastases in mouse models illuminates that the probe may be a convenient tool for fluorescence-guided cancer surgery. To our knowledge, this is the first report to describe the strategy of a zero cross-talk ratiometric NIR GGT fluorescent probe for early cancer diagnosis and fluorescence-guided surgery.


Assuntos
Biomarcadores Tumorais/química , Técnicas Biossensoriais , Fluorescência , Corantes Fluorescentes/química , Imagem Óptica , gama-Glutamiltransferase/química , Animais , Biomarcadores Tumorais/metabolismo , Linhagem Celular , Corantes Fluorescentes/metabolismo , Glutationa/química , Glutationa/metabolismo , Células HCT116 , Células Hep G2 , Humanos , Raios Infravermelhos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Estrutura Molecular , Neoplasias Experimentais/diagnóstico por imagem , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/cirurgia , Espectrometria de Fluorescência , gama-Glutamiltransferase/metabolismo
12.
Appl Opt ; 56(24): 6881-6888, 2017 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-29048028

RESUMO

Even though it is well known that both the magnitude and detailed angular shape of scattering (phase function, PF), particularly in the backward angles, affect the color of the ocean, the current remote-sensing reflectance (Rrs) models typically account for the effect of its magnitude only through the backscattering coefficient (bb). Using 116 volume scattering function (VSF) measurements previously collected in three coastal waters around the U.S. and in the water of the North Atlantic Ocean, we re-examined the effect of particle PF on Rrs in four scenarios. In each scenario, the magnitude of particle backscattering (i.e., bbp) is known, but the knowledge on the angular shape of particle backscattering is assumed to increase from knowing nothing about the shape of particle PFs to partially knowing the particle backscattering ratio (Bp), the exact backscattering shape as defined by ߘp(γ≥90°) (particle VSF normalized by the particle total scattering coefficient), and the exact backscattering shape as defined by the χp factor (particle VSF normalized by the particle backscattering coefficient). At sun zenith angle=30°, the nadir-viewed Rrs would vary up to 65%, 35%, 20%, and 10%, respectively, as the constraints on the shape of particle backscattering become increasingly stringent from scenarios 1 to 4. In all four scenarios, the Rrs variations increase with both viewing and sun angles and are most prominent in the direction opposite the sun. Our results show a greater impact of the measured particle PFs on Rrs than previously found, mainly because our VSF data show a much greater variability in Bp, ߘp(γ≥90°), and χp than previously known. Among the uncertainties in Rrs due to the particle PFs, about 97% can be explained by χp, 90% by ߘp(γ≥90°), and 27% by Bp. The results indicate that the uncertainty in ocean color remote sensing can be significantly constrained by accounting for χp of the VSFs.

13.
Opt Express ; 25(4): A1-A13, 2017 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-28241661

RESUMO

In examining the dependence of the sea surface reflectance of skylight ρs on sky conditions, wind speed, solar zenith angle, and viewing geometry, Mobley [Appl. Opt.38, 7442 (1999).10.1364/AO.38.007442] assumed ρs is independent of wavelength. Lee et al. [Opt. Express18, 26313 (2010).10.1364/OE.18.026313] showed experimentally that ρs does vary spectrally due to the spectral difference of sky radiance coming from different directions, which was ignored in Mobley's study. We simulated ρs from 350 nm to 1000 nm by explicitly accounting for spectral variations of skylight distribution and Fresnel reflectance. Furthermore, we separated sun glint from sky glint because of significant differences in magnitude, spectrum and polarization state between direct sun light and skylight light. The results confirm that spectral variation of ρs(λ) mainly arises from the spectral distribution of skylight and would vary from slightly blueish due to normal dispersion of the refractive index of water, to neutral and then to reddish with increasing wind speeds and decreasing solar zenith angles. Polarization moderately increases sky glint by 8 - 20% at 400 nm but only by 0 - 10% at 1000 nm. Sun glint is inherently reddish and becomes significant (>10% of sky glint) when the sun is at the zenith with moderate winds or when the sea is roughened (wind speeds > 10 m s-1) with solar zenith angles < 20°. We recommend a two-step procedure by first correcting the glint due to direct sun light, which is unpolarized, followed by removing the glint due to diffused and polarized skylight. The simulated ρs(λ) as a function of wind speeds, sun angles and aerosol concentrations for currently recommended sensor-sun geometry, i.e., zenith angle = 40° and azimuthal angle relative to the sun = 45°, is available upon request.

14.
Chem Pharm Bull (Tokyo) ; 60(7): 887-91, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22790823

RESUMO

A series of novel 1,3,4-oxadiazole derivatives based on benzisoselenazolone has been prepared and tested for antiproliferative activity in vitro against the cells of human cancer cell lines: SSMC-7721 (human liver cancer cell), MCF-7 (human breast cancer cell) and A549 (human lung cancer cell). All the compounds obtained exhibited antiproliferative activity and showed selective cytotoxicity against different cancer cells. Compounds 7d and 7i showed significant antiproliferative activities against MCF-7 cells, with IC50 values of 1.07 and 1.76 µM respectively. Compound 7d were found to be the most potent compound against SSMC-7721 cells, with IC50 values 4.46 µM.


Assuntos
Antineoplásicos/síntese química , Oxidiazóis/química , Antineoplásicos/química , Antineoplásicos/toxicidade , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Oxidiazóis/síntese química , Oxidiazóis/toxicidade , Relação Estrutura-Atividade
15.
Bioorg Med Chem Lett ; 22(9): 3191-3, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22483583

RESUMO

A series of novel 1,3,4-thiadiazole-containing benzisoselenazolone derivatives were prepared by the condensation of 2-chloroselenobenzoyl chloride and 2-amino-5-substituted-1,3,4-thiadiazole. Their in vitro antiproliferative activities were evaluated in SSMC-7721, MCF-7 and A-549 cells. The results suggest that, in different tumor cells, some compounds have good antiproliferative activity, certain selectivity and potential value of further research.


Assuntos
Azóis/síntese química , Ensaios de Seleção de Medicamentos Antitumorais , Tiadiazóis/síntese química , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Azóis/farmacologia , Linhagem Celular Tumoral , Humanos , Tiadiazóis/farmacologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...