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1.
BMC Cancer ; 24(1): 170, 2024 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-38310283

RESUMO

BACKGROUND: The prognosis of SCLC is poor and difficult to predict. The aim of this study was to explore whether a model based on radiomics and clinical features could predict the prognosis of patients with limited-stage small cell lung cancer (LS-SCLC). METHODS: Simulated positioning CT images and clinical features were retrospectively collected from 200 patients with histological diagnosis of LS-SCLC admitted between 2013 and 2021, which were randomly divided into the training (n = 140) and testing (n = 60) groups. Radiomics features were extracted from simulated positioning CT images, and the t-test and the least absolute shrinkage and selection operator (LASSO) were used to screen radiomics features. We then constructed radiomic score (RadScore) based on the filtered radiomics features. Clinical factors were analyzed using the Kaplan-Meier method. The Cox proportional hazards model was used for further analyses of possible prognostic features and clinical factors to build three models including a radiomic model, a clinical model, and a combined model including clinical factors and RadScore. When a model has prognostic predictive value (AUC > 0.7) in both train and test groups, a nomogram will be created. The performance of three models was evaluated using area under the receiver operating characteristic curve (AUC) and Kaplan-Meier analysis. RESULTS: A total of 1037 features were extracted from simulated positioning CT images which were contrast enhanced CT of the chest. The combined model showed the best prediction, with very poor AUC for the radiomic model and the clinical model. The combined model of OS included 4 clinical features and RadScore, with AUCs of 0.71 and 0.70 in the training and test groups. The combined model of PFS included 4 clinical features and RadScore, with AUCs of 0.72 and 0.71 in the training and test groups. T stages, ProGRP and smoke status were the independent variables for OS in the combined model, whereas T stages, ProGRP and prophylactic cranial irradiation (PCI) were the independent factors for PFS. There was a statistically significant difference between the low- and high-risk groups in the combined model of OS (training group, p < 0.0001; testing group, p = 0.0269) and PFS (training group, p < 0.0001; testing group, p < 0.0001). CONCLUSION: Combined models involved RadScore and clinical factors can predict prognosis in LS-SCLC and show better performance than individual radiomics and clinical models.


Assuntos
Neoplasias Pulmonares , Carcinoma de Pequenas Células do Pulmão , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Prognóstico , Radiômica , Estudos Retrospectivos , Carcinoma de Pequenas Células do Pulmão/diagnóstico por imagem , Carcinoma de Pequenas Células do Pulmão/terapia , Tomografia Computadorizada por Raios X
2.
Arch Microbiol ; 206(4): 151, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38467842

RESUMO

Salmonella Typhimurium, a zoonotic pathogen, causes systemic and localized infection. The emergence of drug-resistant S. Typhimurium has increased; treating bacterial infections remains challenging. Phage endolysins derived from phages have a broader spectrum of bacteriolysis and better bacteriolytic activity than phages, and are less likely to induce drug resistance than antibiotics. LysST-3, the endolysin of Salmonella phage ST-3, was chosen in our study for its high lytic activity, broad cleavage spectrum, excellent bioactivity, and moderate safety profile. LysST-3 is a promising antimicrobial agent for inhibiting the development of drug resistance in Salmonella. The aim of this study is to investigate the molecular characteristics of LysST-3 through the prediction of key amino acid sites of LysST-3 and detection of its mutants' activity. We investigated its lytic effect on Salmonella and identified its key amino acid sites of interaction with substrate. LysST-3 may be a Ca2+, Mg2+ - dependent metalloenzyme. Its concave structure of the bottom "gripper" was found to be an important part of its amino acid active site. We identified its key sites (29P, 30T, 86D, 88 L, and 89 V) for substrate binding and activity using amino acid-targeted mutagenesis. Alterations in these sites did not affect protein secondary structure, but led to a significant reduction in the cleavage activity of the mutant proteins. Our study provides a basis for phage endolysin modification to target drug-resistant bacteria. Identifying the key amino acid site of the endolysin LysST-3 provides theoretical support for the functional modification of the endolysin and the development of subsequent effective therapeutic solutions.


Assuntos
Bacteriófagos , Fagos de Salmonella , Fagos de Salmonella/genética , Aminoácidos , Endopeptidases/genética , Endopeptidases/farmacologia , Endopeptidases/química , Bacteriófagos/genética , Bacteriófagos/metabolismo , Antibacterianos/farmacologia
3.
Phys Chem Chem Phys ; 26(4): 3110-3116, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38189422

RESUMO

Based on first-principles calculations, we predict a class of graphene-like magnetic materials, transition metal carbonitrides MN4C6 (M = Cr, Mn, Fe, and Co), which are made up of a benzene ring and an MN4 moiety, two common planar units in the compounds. The structural stability is demonstrated by the phonon and molecular dynamics calculations, and the formation mechanism of the planar geometry of MN4C6 is ascribed to the synergistic effect of sp2 hybridization, M-N coordination bond, and π-d conjugation. The MN4C6 materials consist of only one layer of atoms and the transition metal atom is located in the planar crystal field, which is markedly different from most two-dimensional materials. The calculations indicate that MnN4C6, FeN4C6, and CoN4C6 are ferromagnetic while CrN4C6 has an antiferromagnetic ground state. The Curie temperatures are estimated by solving the anisotropic Heisenberg model with the Monte Carlo method.

4.
PLoS Pathog ; 17(5): e1009587, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33974679

RESUMO

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tick-borne emerging phlebovirus with high mortality rates of 6.0 to 30%. SFTSV infection is characterized by high fever, thrombocytopenia, leukopenia, hemorrhage and multiple organ failures. Currently, specific therapies and vaccines remain elusive. Suitable small animal models are urgently needed to elucidate the pathogenesis and evaluate the potential drug and vaccine for SFTSV infection. Previous models presented only mild or no pathogenesis of SFTS, limiting their applications in SFTSV infection. Therefore, it is an urgent need to develop a small animal model for the investigation of SFTSV pathogenesis and evaluation of therapeutics. In the current report, we developed a SFTSV infection model based on the HuPBL-NCG mice that recapitulates many pathological characteristics of SFTSV infection in humans. Virus-induced histopathological changes were identified in spleen, lung, kidney, and liver. SFTSV was colocalized with macrophages in the spleen and liver, suggesting that the macrophages in the spleen and liver could be the principle target cells of SFTSV. In addition, histological analysis showed that the vascular endothelium integrity was severely disrupted upon viral infection along with depletion of platelets. In vitro cellular assays further revealed that SFTSV infection increased the vascular permeability of endothelial cells by promoting tyrosine phosphorylation and internalization of the adhesion molecule vascular endothelial (VE)-cadherin, a critical component of endothelial integrity. In addition, we found that both virus infection and pathogen-induced exuberant cytokine release dramatically contributed to the vascular endothelial injury. We elucidated the pathogenic mechanisms of hemorrhage syndrome and developed a humanized mouse model for SFTSV infection, which should be helpful for anti-SFTSV therapy and pathogenesis study.


Assuntos
Modelos Animais de Doenças , Phlebovirus/patogenicidade , Febre Grave com Síndrome de Trombocitopenia/patologia , Doenças Transmitidas por Carrapatos/patologia , Animais , Plaquetas/patologia , Plaquetas/virologia , Moléculas de Adesão Celular/metabolismo , Células Endoteliais/patologia , Células Endoteliais/virologia , Feminino , Humanos , Leucócitos Mononucleares/patologia , Leucócitos Mononucleares/virologia , Macrófagos/patologia , Macrófagos/virologia , Camundongos , Fosforilação , Febre Grave com Síndrome de Trombocitopenia/virologia , Doenças Transmitidas por Carrapatos/virologia
5.
Environ Res ; 219: 115161, 2023 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-36580981

RESUMO

Soluble extracellular metabolites (SEM) produced by microorganisms might significantly change during sludge bulking, which is a major operational problem caused by the excessive growth of filamentous bacteria. However, knowledge remains limited about the dynamics and potential role of SEM in the bulking of sludge. In this study, filamentous bulking was simulated in a laboratory-scale reactor and changes to SEM characteristics during the bulking process were investigated using excitation-emission matrix spectroscopy and ultrahigh-performance liquid chromatography-mass spectrometry. SEM components changed significantly at different phases of sludge bulking. Changes in SEM were closely correlated with the structure of the bacterial community. Based on the EEM profiles, significant increases in fulvic acid-like and humic acid-like substances in SEM were observed with the development of filamentous bulking. The degree of humification in SEM showed a clear increasing trend. Untargeted extracellular metabolomic analysis showed that the intensity of berberine and isorhamnetin in SEM increased significantly during the bulking phase, which might synergistically facilitate the development of filamentous bulking.


Assuntos
Esgotos , Eliminação de Resíduos Líquidos , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Análise Espectral , Bactérias , Espectrometria de Massas , Reatores Biológicos
6.
Br J Cancer ; 127(8): 1450-1460, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35941174

RESUMO

BACKGROUND: Gastric cancer (GC) is characterised by a heterogeneous tumour microenvironment (TME) that is closely associated with the response to treatment, especially immunotherapies. However, most previous GC molecular subtyping systems need complex gene signatures and examination methods, restricting their clinical applications. Thus, we developed a new TME-based molecular subtype using only two genes. METHODS: Nine independent GC cohorts at the tissue- or single-cell level with more than 2000 patients were used in this study, including data we examined by single-cell sequencing, quantitative RT-PCR and immunochemistry/immunofluorescence staining. Nine different methods, five existing molecular subtypes and a series of signatures were used to evaluate the TME and molecular characteristics of GC. RESULTS: We established a CTSL/ZBTB7B subtyping system and uncovered the novel CTSLHighZBTB7BLow high-risk subgroup, but characterised by relative higher immune cell infiltration and lower tumour purity. This subgroup demonstrate higher levels of immune checkpoints and more enrichment of cancer-related pathways compared with other cases. CONCLUSIONS: We identified a high-risk subpopulation with unique TME features based on expressions of CTSL and ZBTB7B, suggesting a counterbalancing phenotype between immunostimulatory and immunosuppressive mechanisms. This subtyping system could be used to select treatment and management strategies for GC.


Assuntos
Neoplasias Gástricas , Catepsina L , Proteínas de Ligação a DNA/genética , Humanos , Imunoterapia , Fenótipo , Neoplasias Gástricas/patologia , Fatores de Transcrição/genética , Microambiente Tumoral/genética
7.
Microb Pathog ; 169: 105624, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35697172

RESUMO

Salmonella infection is a major public health concern. Several strategies for Salmonella infection prevention and control are currently available including vaccines and antibiotics. However, vaccines are expensive and inefficient, and the use of antibiotics can lead to antibiotic resistance. Thus, alternative strategies for the treatment of Salmonella remain warrant. In this study, recombinant holin HolST-3 and lysin LysST-3 from Salmonella phage ST-3 were expressed and purified, and their bactericidal properties were analyzed. HolST-3 and LysST-3 possessed a wider lysis spectrum and more efficient bactericidal effect than phage ST-3, and a synergistic bactericidal effect was observed when combined in vitro. In addition, we explored the bactericidal properties of HolST-3 and LysST-3 in vivo using zebrafish as a model organism, and found that the bactericidal effects of both HolST-3 and LysST-3 in vivo were comparable to those of cefotaxime, an antibiotic. This study provides a basis for the development of HolST-3 and LysST-3 as novel bactericidal agents for the prevention and treatment of infectious diseases caused by Salmonella spp.


Assuntos
Infecções por Salmonella , Fagos de Salmonella , Animais , Antibacterianos/farmacologia , Myoviridae , Salmonella , Infecções por Salmonella/terapia , Fagos de Salmonella/genética , Peixe-Zebra
8.
Curr Microbiol ; 79(12): 371, 2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36269452

RESUMO

The novel phage ST-3, capable of infecting the foodborne pathogen Salmonella Typhimurium, was isolated from wastewater. The Biological characters and genome information of ST-3 were analyzed. In the in vitro assay, the phage ST-3 with a MOI of 10 effectively inhibited the growth of Salmonella Typhimurium CGMCC 1.1174 in 6 h. The inhibitory effect of combination phage ST-3 and antibiotics was also studied, the removal rate of planktonic host exposed to ST-3 and levofloxacin hydrochloride at the same time, or to ciprofloxacin followed by ST-3, is higher than that exposed to antibiotic dosing group alone and antibiotic + phage dosing group. The phage ST-3 combined with 0.5 µg/mL levofloxacin hydrochloride resulted in the largest decrease in biofilm biomass at 54%. The phage ST-3 could be a potential agent to control Salmonella Typhimurium growth and provide instruction for use it and antibiotics together.


Assuntos
Bacteriófagos , Fagos de Salmonella , Salmonella typhimurium/genética , Antibacterianos/farmacologia , Levofloxacino/farmacologia , Águas Residuárias , Ciprofloxacina/farmacologia , Bacteriófagos/genética , Myoviridae , Fagos de Salmonella/genética
9.
Sensors (Basel) ; 22(19)2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36236502

RESUMO

Thermal infrared hyperspectral imager is one of the frontier payloads in current hyperspectral remote sensing research. It has broad application prospects in land and ocean temperature inversion, environmental monitoring, and other fields. However, due to the influence of the production process of the infrared focal plane array and the characteristics of the material itself, the infrared focal plane array inevitably has blind pixels, resulting in spectral distortion of the data or even invalid data, which limits the application of thermal infrared hyperspectral data. Most of the current blind pixels detection methods are based on the spatial dimension of the image, that is, processing single-band area images. The push-broom thermal infrared hyperspectral imager works completely different from the conventional area array thermal imager, and only one row of data is obtained per scan. Therefore, the current method cannot be directly applied to blind pixels detection of push-broom thermal infrared hyperspectral imagers. Based on the imaging principle of push-broom thermal infrared hyperspectral imager, we propose a practical blind pixels detection method. The method consists of two stages to detect and repair four common types of blind pixels: dead pixel, dark current pixel, blinking pixel, and noise pixel. In the first stage, dead pixels and dark current pixels with a low spectral response rate are detected by spectral filter detection; noise pixels are detected by spatial noise detection; and dark current pixels with a negative response slope are detected by response slope detection. In the second stage, according to the random appearance of blinking pixels, spectral filter detection is used to detect and repair spectral anomalies caused by blinking pixels line by line. In order to verify the effectiveness of the proposed method, a flight test was carried out, using the Airborne Thermal-infrared Hyperspectral Imaging System (ATHIS), the latest thermal infrared imager in China, for data acquisition. The results show that the method proposed in this paper can accurately detect and repair blind pixel, thus effectively eliminating spectral anomalies and significantly improving image quality.


Assuntos
Cytisus , China , Temperatura
10.
Sensors (Basel) ; 22(5)2022 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-35270966

RESUMO

Here, we report a novel technology for the fabrication of copper-electroplating-modified liquid metal microelectrodes. This technology overcomes the complexity of the traditional fabrication of sidewall solid metal electrodes and successfully fabricates a pair of tiny stable solid-contact microelectrodes on both sidewalls of a microchannel. Meanwhile, this technology also addresses the instability of liquid metal electrodes when directly contacted with sample solutions. The fabrication of this microelectrode depends on controllable microelectroplating of copper onto the gallium electrode by designing a microelectrolyte cell in a microfluidic chip. Using this technology, we successfully fabricate various microelectrodes with different microspacings (from 10 µm to 40 µm), which were effectively used for capacitive sensing, including droplet detection and oil particle counting.


Assuntos
Gálio , Técnicas Analíticas Microfluídicas , Cobre , Galvanoplastia , Microeletrodos , Microfluídica
11.
Molecules ; 27(24)2022 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-36558152

RESUMO

Sensitive detection methods for T4 polynucleotide kinase/phosphatase (T4 PNKPP) are urgently required to obtain information on malignancy and thereby to provide better guidance in PNKP-related diagnostics and drug screening. Although the CRISPR/Cas12a system shows great promise in DNA-based signal amplification protocols, its guide RNAs with small molecular weight often suffer nuclease degradation during storage and utilization, resulting in reduced activation efficiency. Herein, we proposed a self-supplying guide RNA-mediated CRISPR/Cas12a system for the sensitive detection of T4 PNKP in cancer cells, in which multiple copies of guide RNA were generated by in situ transcription. In this assay, T4 PNKP was chosen as a model, and a dsDNA probe with T7 promoter region and the transcription region of guide RNA were involved. Under the action of T4 PNKP, the 5'-hydroxyl group of the dsDNA probe was converted to a phosphate group, which can be recognized and digested by Lambda Exo, resulting in dsDNA hydrolysis. The transcription template was destroyed, which resulted in the failure to generate guide RNA by the transcription pathway. Therefore, the CRISPR/Cas12a system could not be activated to effectively cleavage the F-Q-reporter, and the fluorescence signal was turned off. In the absence of T4 PNKP, the 5'-hydroxyl group of the substrate DNA cannot be digested by Lambda Exo. The intact dsDNA acts as the transcription template to generate a large amount of guide RNA. Finally, the formed Cas12a/gRNA complex triggered the reverse cleavage of Cas12a on the F-Q-reporter, resulting in a "turn-on" fluorescence signal. This strategy displayed sharp sensitivity of T4 PNKP with the limit of detection (LOD) down to 0.0017 mU/mL, which was mainly due to the multiple regulation effect of transcription amplification. In our system, the dsDNA simultaneously serves as the T4 PNKP substrate, transcription template, and Lambda Exo substrate, avoiding the need for multiple probe designs and saving costs. By integrating the target recognition, Lambda Exo activity, and trans-cleavage activity of Cas12a, CRISPR/Cas12a catalyzed the cleavage of fluorescent-labeled short-stranded DNA probes and enabled synergetic signal amplification for sensitive T4 PNKP detection. Furthermore, the T4 PNKP in cancer cells has been evaluated as a powerful tool for biomedical research and clinical diagnosis, proving a good practical application capacity.


Assuntos
Sistemas CRISPR-Cas , DNA , Sistemas CRISPR-Cas/genética , DNA/genética , DNA/química , Polinucleotídeo 5'-Hidroxiquinase/genética , Polinucleotídeo 5'-Hidroxiquinase/metabolismo , Sondas de DNA/química , Corantes Fluorescentes/química , RNA
12.
Bioorg Chem ; 116: 105322, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34488127

RESUMO

Bacillary dysentery is a common foodborne disease with an exaggerated mortality rate because of Shigella infection. With the increasing severity of Shigella infection, lyase has been considered as the most promising alternative to antimicrobial agents, owing to the emergence of resistant bacteria and the difficulty in disrupting and eliminating bacterial biofilms. In this study, we cloned and characterised HolSSE1 and LysSSE1, holin, and lysozyme from the S. dysenteriae phage SSE1 with extended bacterial host range against common gram-negative and gram-positive bacteria. In addition, the efficacy of HolSSE1 and LysSSE1 in removing bacterial biofilms was observed on polystyrene surfaces. Moreover, synergistic bacteriostasis was observed when they were used together. Alignment and structural model analysis showed that both HolSSE1 and LysSSE1 are T4 phage proteins that have not yet been identified. Therefore, HolSSE1 and LysSSE1 can be promising biocontrol agents for the prevention and treatment of various pathogenic infections.


Assuntos
Antibacterianos/farmacologia , Liases/metabolismo , Shigella dysenteriae/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Biofilmes/efeitos dos fármacos , Relação Dose-Resposta a Droga , Liases/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade
13.
Biol Pharm Bull ; 44(9): 1263-1271, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34162786

RESUMO

Herpes simplex virus-1 (HSV-1) infection of the eyes leads to herpes simplex virus keratitis (HSK), the main cause of infectious blindness in the world. As the current therapeutics for HSV-1 infection are rather limited and prolonged use of acyclovir (ACV)/ganciclovir (GCV) and in immunocompromised patients lead to the rise of drug resistant mutants, it underlines the urgent need for new antiviral agents with distinct mechanisms. Our study attempted to establish ras-related C3 botulinum toxin substrate 1 (Rac1) as a new therapeutic target for HSV-1 infection by using Rac1-specific inhibitors to evaluate the in vitro inhibition of virus growth. Our results showed that increased Rac1 activity facilitated HSV-1 replication and inhibition of Rac1 activity by NSC23766 and Ehop016 significantly reduced HSV-1 replication. Thus, we identified NSC23766 and Ehop016 as possessing potent anti-HSV-1 activities by suppressing the Rac1 activity, suggesting that Rac1 is a potential target for treating HSV-1-related diseases.


Assuntos
Aminoquinolinas/farmacologia , Antivirais/farmacologia , Carbazóis/farmacologia , Herpes Simples/tratamento farmacológico , Pirimidinas/farmacologia , Proteínas rac1 de Ligação ao GTP/antagonistas & inibidores , Aminoquinolinas/uso terapêutico , Animais , Antivirais/uso terapêutico , Carbazóis/uso terapêutico , Chlorocebus aethiops , Avaliação Pré-Clínica de Medicamentos , Células HeLa , Herpes Simples/virologia , Herpesvirus Humano 1/efeitos dos fármacos , Herpesvirus Humano 1/fisiologia , Humanos , Pirimidinas/uso terapêutico , Células Vero , Replicação Viral/efeitos dos fármacos , Proteínas rac1 de Ligação ao GTP/metabolismo
14.
Sensors (Basel) ; 19(10)2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31137774

RESUMO

Developing sensing materials for military explosives and improvised explosive precursors is of great significance to maintaining homeland security. 5-Nitro-1,10-phenanthroline (Aphen)-modified TiO2 nanospheres are prepared though coordination interactions, which broaden the absorption band edge of TiO2 and shift it to the visible region. A sensor array based on an individual TiO2/Aphen sensor is constructed by regulating the excitation wavelength (365 nm, 450 nm, 550 nm). TiO2/Aphen shows significant response to nitroaromatic explosives since the Aphen capped on the surface of TiO2 can chemically recognize and absorb nitroaromatic explosives by the formation of the corresponding Meisenheimer complex. The photocatalytic mechanism is proved to be the primary sensing mechanism after anchoring nitroaromatic explosives to TiO2. The fingerprint patterns obtained by combining kinetics and thermodynamics validated that the single TiO2/Aphen sensor can identify at least six nitroaromatic explosives and improvised explosives within 8 s and the biggest response reaches 80%. Furthermore, the TiO2/Aphen may allow the contactless detection of various explosives, which is of great significance to maintaining homeland security.

15.
Sensors (Basel) ; 19(23)2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31779193

RESUMO

Polarimetric synthetic aperture radar is an important tool in the effective detection of marine oil spills. In this study, two cases of Radarsat-2 Fine mode quad-polarimetric synthetic aperture radar datasets are exploited to detect a well-known oil seep area that collected over the Gulf of Mexico using the same research area, sensor, and time. A novel oil spill detection scheme based on a multi-polarimetric features model matching method using spectral pan-similarity measure (SPM) is proposed. A multi-polarimetric features curve is generated based on optimal polarimetric features selected using Jeffreys-Matusita distance considering its ability to discriminate between thick and thin oil slicks and seawater. The SPM is used to search for and match homogeneous unlabeled pixels and assign them to a class with the highest similarity to their spectral vector size, spectral curve shape, and spectral information content. The superiority of the SPM for oil spill detection compared to traditional spectral similarity measures is demonstrated for the first time based on accuracy assessments and computational complexity analysis by comparing with four traditional spectral similarity measures, random forest (RF), support vector machine (SVM), and decision tree (DT). Experiment results indicate that the proposed method has better oil spill detection capability, with a higher average accuracy and kappa coefficient (1.5-7.9% and 1-25% higher, respectively) than the four traditional spectral similarity measures under the same computational complexity operations. Furthermore, in most cases, the proposed method produces valuable and acceptable results that are better than the RF, SVM, and DT in terms of accuracy and computational complexity.

16.
Sensors (Basel) ; 19(4)2019 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-30795616

RESUMO

The homemade explosive, triacetone triperoxide (TATP), is easy to synthesize, sensitive to detonation but hard to detect directly. Vapor sensor arrays composed of a few sensor materials have the potential to discriminate TATP, but the stability of the sensor array is always a tricky problem since each sensor may encounter a device fault. Thus, a sensor array based on a single optoelectronic TiO2/PW11 sensor was first constructed by regulating the excitation wavelength to discriminate TATP from other explosives. By in situ doping of Na3PW12O40, a Keggin structure of PW11 formed on the TiO2 to promote the photoinduced electron-hole separation, thus obviously improving the detection sensitivity of the sensor film and shortening the response time. The response of the TiO2/PW11 sensor film to TATP under 365, 450 and 550 nm illumination is 81%, 42%, and 37%, respectively. The TiO2/PW11 sensor features selectivity to TATP and is able to detect less than 50 ppb. The flexibility and stability of the flexible sensor film is also demonstrated with the extent of bending. Furthermore, the sensing response cannot be affected by ambient air below 60% relative humidity.

17.
Sensors (Basel) ; 18(1)2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-29342945

RESUMO

Researchers have studied oil spills in open waters using remote sensors, but few have focused on extracting reflectance features of oil pollution on sea ice. An experiment was conducted on natural sea ice in Bohai Bay, China, to obtain the spectral reflectance of oil-contaminated sea ice. The spectral absorption index (SAI), spectral peak height (SPH), and wavelet detail coefficient (DWT d5) were calculated using stepwise multiple linear regression. The reflectances of some false targets were measured and analysed. The simulated false targets were sediment, iron ore fines, coal dust, and the melt pool. The measured reflectances were resampled using five common sensors (GF-2, Landsat8-OLI, Sentinel3-OLCI, MODIS, and AVIRIS). Some significant spectral features could discriminate between oil-polluted and clean sea ice. The indices correlated well with the oil area fractions. All of the adjusted R² values exceeded 0.9. The SPH model1, based on spectral features at 507-670 and 1627-1746 nm, displayed the best fitting. The resampled data indicated that these multi-spectral and hyper-spectral sensors could be used to detect crude oil on the sea ice if the effect of noise and spatial resolution are neglected. The spectral features and their identified changes may provide reference on sensor design and band selection.

18.
J Environ Manage ; 206: 633-641, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-29132086

RESUMO

To develop an efficient and environmental-friendly approach to detoxicate nickel (Ni) and fluoranthene co-contaminated soil, the combined application of Coprinus comatus (C. comatus) with Serratia sp. FFC5 and/or Enterobacter sp. E2 was investigated. The pot experiment tested the influences of bacterial inoculation on the growth of C. comatus, content of Ni in C. comatus, Ni speciation in soil, fluoranthene dissipation, soil enzymatic activities, bacterial population and community structure. With the inoculation of bacteria, the fresh weights of C. comatus, concentration of Ni in C. comatus and the dissipation rates of fluoranthene were increased by 17.73-29.38%, 68.97-204.97% and 34.84-60.90%, respectively. Notably, results illustrated that the co-inoculation of FFC5 and E2 showed better effect in biomass enhancement, Ni accumulation and fluoranthene dissipation than solitary inoculation. Simultaneously, higher soil enzymatic and microbiological activities suggested that the integrated detoxication method of bacteria and C. comatus could improve soil quality. Therefore, we can infer that bacterial inoculation strengthened detoxication effect of C. comatus in Ni-fluoranthene co-contaminated soil, indicating that the combined application of C. comatus and bacteria can be an efficient alternative for detoxicating Ni and fluoranthene co-contaminated soil.


Assuntos
Biodegradação Ambiental , Coprinus , Fluorenos/isolamento & purificação , Níquel/isolamento & purificação , Poluentes do Solo/isolamento & purificação , Bactérias , Solo , Microbiologia do Solo
20.
Arch Environ Contam Toxicol ; 73(1): 154-169, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28695250

RESUMO

Current marine oil spill detection and monitoring methods using high-resolution remote sensing imagery are quite limited. This study presented a new bottom-up and top-down visual saliency model. We used Landsat 8, GF-1, MAMS, HJ-1 oil spill imagery as dataset. A simplified, graph-based visual saliency model was used to extract bottom-up saliency. It could identify the regions with high visual saliency object in the ocean. A spectral similarity match model was used to obtain top-down saliency. It could distinguish oil regions and exclude the other salient interference by spectrums. The regions of interest containing oil spills were integrated using these complementary saliency detection steps. Then, the genetic neural network was used to complete the image classification. These steps increased the speed of analysis. For the test dataset, the average running time of the entire process to detect regions of interest was 204.56 s. During image segmentation, the oil spill was extracted using a genetic neural network. The classification results showed that the method had a low false-alarm rate (high accuracy of 91.42%) and was able to increase the speed of the detection process (fast runtime of 19.88 s). The test image dataset was composed of different types of features over large areas in complicated imaging conditions. The proposed model was proved to be robust in complex sea conditions.


Assuntos
Monitoramento Ambiental/métodos , Modelos Químicos , Poluição por Petróleo/análise , Petróleo/análise , Tecnologia de Sensoriamento Remoto , Poluentes Químicos da Água/análise
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