Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
RSC Adv ; 12(37): 24139, 2022 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-36108320

RESUMO

[This retracts the article DOI: 10.1039/C7RA11763A.].

2.
Artigo em Inglês | MEDLINE | ID: mdl-35341149

RESUMO

Early and automatic detection of colorectal tumors is essential for cancer analysis, and the same is implemented using computer-aided diagnosis (CAD). A computerized tomography (CT) image of the colon is being used to identify colorectal carcinoma. Digital imaging and communication in medicine (DICOM) is a standard medical imaging format to process and analyze images digitally. Accurate detection of tumor cells in the complex digestive tract is necessary for optimal treatment. The proposed work is divided into two phases. The first phase involves the segmentation, and the second phase is the extraction of the colon lesions with the observed segmentation parameters. A deep convolutional neural network (DCNN) based residual network approach for the colon and polyps' segmentation from the CT images is applied over the 2D CT images. The residual stack block is being added to the hidden layers with short skip nuance, which helps to retain spatial information. ResNet-enabled CNN is employed in the current work to achieve complete boundary segmentation of the colon cancer region. The results obtained through segmentation serve as features for further extraction and classification of benign as well as malignant colon cancer. Performance evaluation metrics indicate that the proposed network model has effectively segmented and classified colorectal tumors with dice scores of 91.57% (on average), sensitivity = 98.28, specificity = 98.68, and accuracy = 98.82.

3.
Ultrason Sonochem ; 58: 104596, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31450358

RESUMO

Herein, we report a super-active electrocatalyst of copper(II) oxide nanoparticles (CuO NPs) decorated functionalized multiwalled carbon nanotubes (CuO NPs@f-MWCNTs) by the ultrasonic method. The as-synthesized CuO NPs@f-MWCNTs was characterized through the FESEM, XPS, XRD and electrochemical impedance spectroscopy (EIS). The combination of highly active CuO NPs and highly conductive f-MWCNTs film with rapid detection enables this nanohybrid to display excellent electrochemical performance towards anesthesia drug. Furthermore, the hybrid electrocatalyst modified SPCE was developed for the determination of flunitrazepam (FTM) for the first time. FTM is important anesthesia drug with high adverse effect in human body. Benefiting from the synergistic reaction of CuO NPs and f-MWCNTs, this nanohybrid exhibited high sensitivity and specificity towards FTM electro-reduction. The CuO NPs@f-MWCNTs film modified SPCE exhibits outstanding electrochemical activity including excellent reproducibility, wide linear range from 0.05 to 346.6 µM with nanomolar limit of detection for FTM detection. Further, the as-modified CuO NPs@f-MWCNTs/SPCE has been applied to determination of FTM in biological and drug samples with satisfactory recovery results, thereby showing a notable potential for extensive (bio) sensor applications.


Assuntos
Antibacterianos/análise , Cobre/química , Eletroquímica/instrumentação , Flunitrazepam/análise , Limite de Detecção , Nanosferas/química , Nanotubos de Carbono/química , Antibacterianos/sangue , Antibacterianos/química , Antibacterianos/urina , Técnicas de Química Sintética , Eletrodos , Flunitrazepam/sangue , Flunitrazepam/química , Flunitrazepam/urina , Humanos , Nanotecnologia , Fatores de Tempo
4.
Ultrason Sonochem ; 58: 104618, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31450380

RESUMO

In this study, a super-active Iron (II, III) oxide nanospheres (Fe3O4 NPs) decorated reduced graphene oxide (rGOS) nanocomposite was developed. Fe3O4 NPs were stabilized on rGOS through electrostatic interactions in the aqueous medium. This process involves an ultrasound assisted reduction reaction of the GOS. The as-synthesized Fe3O4 NPs@rGOS was characterized through the HRTEM, SEM, XRD, Raman, elemental mapping and EDX analysis. The Fe3O4 NPs@rGOS modified GCE was developed for the determination of biomarker. Uric acid is important biomarker based on gout and kidney stone with high adverse effect in human body. The results obtained showed that the modified electrode Fe3O4 NPs@rGOS shows good electrochemical reduction peak compared to bare electrode and control electrodes. The Fe3O4 NPs@rGOS modified sensor linear range 0.02-783.6 µM was observed with nanomolar LOD 0.12 nM. In addition, the modified Fe3O4 NPs@rGOS/GCE sensor has been applied to determination of uric acid concentration in urine and blood serum samples. Furthermore, advantages of the modified sensor are high stability, repeatability and reproducibility.


Assuntos
Testes de Química Clínica/métodos , Grafite/química , Limite de Detecção , Nanopartículas de Magnetita/química , Ondas Ultrassônicas , Ácido Úrico/sangue , Ácido Úrico/urina , Técnicas de Química Sintética , Testes de Química Clínica/instrumentação , Eletroquímica , Humanos , Concentração de Íons de Hidrogênio , Nanotecnologia , Oxirredução , Óxidos/química , Ácido Úrico/química
5.
Ultrason Sonochem ; 56: 134-142, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31101247

RESUMO

Herein, we have reported a simple sonochemical synthesis of multi-layer graphene covered tungsten trioxide nanoballs (WO3 NBs) and the nanocomposite was characterized by FESEM, HRTEM, XRD, XPS, CV and EIS. Furthermore, progesterone (PGT) is a preferred marker for various biological problems like pregnancy problem, mood swings, anxiety, depression, nervousness and body pain. Therefore, its selective and sensitive determination in various biological fluids is beneficial for the evaluation of malformation problems. We describe the fabrication of an amperometric and non-enzymatic biosensor based on WO3 NBs@GR nanocomposite modified electrode for nanomolar detection of PGT. The results showed that the nanocomposite modified electrode exhibit well-defined electro-oxidation peak compared to bare and control electrodes, demonstrating the superior electrocatalytic ability and performances. The fabricated modified sensor was facilitates the analysis of PGT in the concentration ranges of 0.025-1792.5 µM with a low detection limit of 4.28 nM. Further, the as-prepared WO3 NBs@GR electrode has been applied to determination of PGT in human blood samples with outstanding recovery results and more importantly, the facile and environment-friendly sonochemical construction strategy extended here, may be open a cost-effective way for setting up the nanocomposites based (bio) sensing platform.


Assuntos
Eletroquímica/instrumentação , Grafite/química , Limite de Detecção , Óxidos/química , Tungstênio/química , Ondas Ultrassônicas , Catálise , Técnicas de Química Sintética , Eletrodos , Oxirredução , Propriedades de Superfície , Temperatura
6.
Ultrason Sonochem ; 56: 318-326, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31101269

RESUMO

A simple and facile ultrasound based sonochemical method to incorporate Perovskite-type barium titanate (BaTiO3) nanoparticles inside the layered and reduced graphene oxide sheets (rGOs) is reported. BaTiO3@rGOs nanocomposite was characterized by FESEM, HRTEM, EDX, mapping, XRD, XPS and EIS. The results show that the decoration and also incorporation of BaTiO3 nanoparticles in the multi-layered and ultrasound reduced graphene oxide matrix. Non-enzymatic and differential pulse voltammetric sensor of ractopamine (food toxic) based on the BaTiO3@rGOs nanocomposite modified screen printed carbon electrode is developed. Compared with the original BaTiO3/SPCE and rGOs/SPCE, the BaTiO3@rGOs/SPCE displays excellent current response towards ractopamine and gives linearity in the range of 0.01-527.19 µM ractopamine in neutral phosphate buffer (pH 7.0). The BaTiO3@rGOs nanocomposite modified sensor also exhibits valuable ability of anti-interference to electroactive analytes. Furthermore, the as-prepared BaTiO3 NPs@rGOs/SPCE has been applied to the determination of ractopamine in pork and chicken samples.


Assuntos
Compostos de Cálcio/química , Grafite/química , Carne/análise , Nanopartículas/química , Óxidos/química , Fenetilaminas/análise , Titânio/química , Ondas Ultrassônicas , Técnicas de Química Sintética , Eletroquímica , Eletrodos , Análise de Alimentos , Contaminação de Alimentos/análise , Modelos Moleculares , Conformação Molecular , Oxirredução , Propriedades de Superfície , Fatores de Tempo
7.
Ultrason Sonochem ; 56: 422-429, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31101280

RESUMO

The nanomaterials have received enormous attention in the catalysis applications. Particularly, we have focused on the fabrication of nanocomposite for an electrochemical sensor with improved electrocatalytic performance. Herein, a rapid and sensitive electrochemical detection of nitrite is essential for assessing the risks facing ecosystems in environment. We report a simple and robust ultrasonic-assisted synthetical route via prepared Er2O3 nanoparticles decorated reduced graphene oxide nanocomposite (Er2O3 NPs@RGO) modified electrode for nitrite detection. The composition and morphological formation were characterized by XRD, XPS, FESEM, and HRTEM. The amperometric (i-t) and cyclic voltammetry were exhibits tremendous electrocatalytic capability and superior performance toward nitrite oxidation. A sensitive and reproducible amperometric nitrite sensor was fabricated which able to detect trace concentration as 3.69 nM and excellent sensitivity (24.17 µA µM-1 cm-2). The method worked well even in cured meat and water samples and the results has indicates the reliability of the method in real-time analysis.


Assuntos
Poluentes Ambientais/análise , Érbio/química , Grafite/química , Metemoglobinemia/induzido quimicamente , Nanosferas/química , Nitritos/análise , Óxidos/química , Catálise , Técnicas de Química Sintética , Eletroquímica , Eletrodos , Poluentes Ambientais/toxicidade , Limite de Detecção , Nitritos/toxicidade , Reprodutibilidade dos Testes , Propriedades de Superfície , Ondas Ultrassônicas
8.
Ultrason Sonochem ; 54: 79-89, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30833196

RESUMO

In this paper, mesoporous tungsten sulfide electrocatalyst (MP-WS2) were developed through a facile sonochemical technique (SC) and utilized as an electrocatalyst for the sensitive electrochemical detection of Psychoactive drug. The as-prepared SC-MP-WS2 NRs and HT-WS2 NPs (hydrothermally synthesized) were characterized using XRD, Raman, XPS, FESEM, HRTEM, BET, EDX, and electrochemical analysis, which exposed the formation of WS2 in the form of mesoporous nanorods in shape. Further, the use of the as-developed SC-MP-WS2 NRs and HT-WS2 NPs as an electrocatalyst for the detection of clonazepam (CNP). Interestingly, the SC-MP-WS2 NRs modified screen-printed carbon electrode (SC-MP-WS2 NRs/SPCE) exhibited an excellent electrocatalytic performance, and enhanced reduction peak current when compared to HT-WS2 NPs with unmodified electrode. Moreover, as-prepared SC-MP-WS2 NRs/SPCE displayed wide linear response range (10-551 µM), lower detection limit (2.37 nM) and high sensitivity (24.32 µAµM-1cm-2). Furthermore, SC-MP-WS2 NRs/SPCE showed an excellent selectivity even in the existence of potentially co-interfering compounds. The proposed sensor was successfully applied for the determination of CNP in biological and drug samples with acceptable recovery.


Assuntos
Clonazepam/análise , Nanotubos/química , Psicotrópicos/análise , Temperatura , Tungstênio/química , Ondas Ultrassônicas , Carbono/química , Catálise , Clonazepam/sangue , Eletroquímica , Eletrodos , Humanos , Limite de Detecção , Modelos Moleculares , Conformação Molecular , Porosidade , Psicotrópicos/sangue
9.
Ultrason Sonochem ; 54: 90-98, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30846281

RESUMO

Herein, we developed a silver nanoparticles decorated iron pyrite flowers (FeS2@Ag NL) based nanocomposite was prepared by a sonochemical method. The formation of FeS2@Ag NL nanocomposite was confirmed by XRD, XPS, HR-TEM and analytical techniques. The FeS2@Ag NL/SPCE was potentially applied towards electrochemical detection of toxic herbicide (acifluorfen-AFF). This provided an efficient sensor platform anchoring FeS2@Ag NL on its surface. Under optimized conditions of differential pulse voltammetric transduction, a linear relationship between the current and the concentration was obtained in the range of 0.05-1126.45 µM for Acifluorfen. The detection limit was observed to be 0.0025 µM. the modified sensor exhibits excellent electrochemical performance, including good linear range, nanomolar detection limit, high sensitivity, and desirable stability. Particularly, the practical applicability was revealed by quantifying the AFF concentration in biological samples.

10.
J Photochem Photobiol B ; 177: 62-68, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29069633

RESUMO

Green synthesis of silver nanoparticles (Ag NPs) using an extract of dried Zingiber officinale (ginger) root as a reducing and capping agent in the presence of microwave irradiation was herein reported for the first time. The formation of symmetrical spheres is confirmed from the UV-Visible spectrum of Ag NPs. Fourier transform infra-red spectroscopy confirms the formation of the Ag NPs. X-ray diffraction analysis was utilized to calculate the crystallite size of Ag NPs and the value was found to be 10nm. High-resolution transmission electron microscopy and high-resolution scanning electron microscopy were used to investigate the morphology and size of the synthesized samples. The sphere like morphology is confirmed from the images. The purity and crystallinity of Ag NPs is confirmed by energy-dispersive X-Ray analysis and selected area electron diffraction respectively. The electrochemical behavior of the synthesized Ag NPs was assessed by cyclic voltammetry (CV) and shows the redox peaks in the potential range of -1.1 to +1.1V. Agar diffusion method is used to examine the antibacterial activity of Ag NPs. For this purpose, two gram positive and two gram negative bacteria were studied. This single step approach was found to be simple, short time, cost-effective, reproducible, and eco-friendly.


Assuntos
Antibacterianos/síntese química , Antibacterianos/farmacologia , Química Verde , Nanopartículas Metálicas/química , Prata/química , Zingiber officinale/química , Antibacterianos/química , Técnicas Eletroquímicas , Zingiber officinale/metabolismo , Bactérias Gram-Negativas/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Extratos Vegetais/química , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...