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Sensors (Basel) ; 21(18)2021 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-34577327


Toxic and nontoxic volatile organic compound (VOC) gases are emitted into the atmosphere from certain solids and liquids as a consequence of wastage and some common daily activities. Inhalation of toxic VOCs has an adverse effect on human health, so it is necessary to monitor their concentration in the atmosphere. In this work, we report on the fabrication of inorganic nanotube (INT)-tungsten disulfide, paper-based graphene-PEDOT:PSS sheet and WS2 nanotube-modified conductive paper-based chemiresistors for VOC gas sensing. The WS2 nanotubes were fabricated by a two-step reaction, that is oxide reduction and sulfurization, carried out at 900 °C. The synthesized nanotubes were characterized by FE-SEM, EDS, XRD, Raman spectroscopy, and TEM. The synthesized nanotubes were 206-267 nm in diameter. The FE-SEM results show the length of the nanotubes to be 4.5-8 µm. The graphene-PEDOT:PSS hybrid conductive paper sheet was fabricated by a continuous coating process. Then, WS2 nanotubes were drop-cast onto conductive paper for fabrication of the chemiresistors. The feasibility and sensitivity of the WS2 nanotube-modified paper-based chemiresistor were tested in four VOC gases at different concentrations at room temperature (RT). Experimental results show the proposed sensor to be more sensitive to butanol gas when the concentration ranges from 50 to 1000 ppm. The limit of detection (LOD) of this chemiresistor for butanol gas was 44.92 ppm. The WS2 nanotube-modified paper-based chemiresistor exhibits good potential as a VOC sensor with the advantages of flexibility, easy fabrication, and low fabrication cost.

Nanotubos , Compostos Orgânicos Voláteis , Dissulfetos , Humanos , Limite de Detecção , Tungstênio
Sensors (Basel) ; 16(7)2016 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-27409621


Most individuals with intellectual disabilities (ID) demonstrate problems in learning and movement coordination. Consequently, they usually have difficulties in activities such as standing, walking, and stair climbing. To monitor the physical impairments of these children, regular gross motor evaluation is crucial. Straight-line level walking is the most frequently used test of their mobility. However, numerous studies have found that unless the children have multiple disabilities, no significant differences can be found between the children with ID and typically-developed children in this test. Stair climbing presents more challenges than level walking because it is associated with numerous physical factors, including lower extremity strength, cardiopulmonary endurance, vision, balance, and fear of falling. Limited ability in those factors is one of the most vital markers for children with ID. In this paper, we propose a sensor-based approach for measuring stair-walking performance, both upstairs and downstairs, for adolescents with ID. Particularly, we address the problem of sensor calibration to ensure measurement accuracy. In total, 62 participants aged 15 to 21 years, namely 32 typically-developed (TD) adolescents, 20 adolescents with ID, and 10 adolescents with multiple disabilities (MD), participated. The experimental results showed that stair-walking is more sensitive than straight-line level walking in capturing gait characteristics for adolescents with ID.

Deficiência Intelectual/fisiopatologia , Caminhada/fisiologia , Acelerometria , Adolescente , Análise de Variância , Humanos , Reprodutibilidade dos Testes , Rotação , Processamento de Sinais Assistido por Computador , Adulto Jovem
Materials (Basel) ; 7(11): 7366-7378, 2014 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-28788252


Cu electrodeposition was performed on a cylindrical AZ80 substrate with a U-shaped surface. A uniform deposition of Cu was achieved on an AZ80 electrode via galvanostatic etching, followed by Cu electrodeposition in an eco-friendly alkaline Cu plating bath. Improper wetting and lower rotational speeds of the AZ80 electrode resulted in an uneven Cu deposition at the inner upper site of the U-shaped surface during the Cu electroplating process. This wetting effect could be deduced from the variation in the anodic potential during the galvanostatic etching. The corrosion resistance of the Cu-deposited AZ80 electrode can be considerably improved after Ni electroplating.

Biomaterials ; 31(26): 6849-58, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20619787


In this study, we report the biodistribution of aspart-insulin, a rapid-acting insulin analogue, following oral or subcutaneous (SC) administration to rats using the single-photon emission computed tomography (SPECT)/computed tomography (CT). Oral delivery of aspart-insulin was achieved using a pH-responsive nanoparticle (NP) system composed of chitosan (CS) and poly(gamma-glutamic acid). The results obtained in the SPECT/CT study indicate that the orally administered aspart-insulin was absorbed into the systemic circulation, while the drug carrier (CS) was mainly retained in the gastrointestinal tract.Via the SC route, the peak aspart-insulin concentration in the peripheral tissue/plasma was observed at 20 min after injection. Within 3 h, half of the initial dose (ID) of aspart-insulin was degraded and excreted into the urinary bladder. In contrast, via oral delivery, there was constantly circulating aspart-insulin in the peripheral tissue/plasma during the course of the study, while 20% of the ID of aspart-insulin was metabolized and excreted into the urinary bladder. In the pharmacodynamic (PD) and pharmacokinetic (PK) evaluation in a diabetic rat model, the orally administered aspart-insulin loaded NPs produced a slower hypoglycemic response for a prolonged period of time, whereas the SC injection of aspart-insulin produced a more pronounced hypoglycemic effect for a relatively shorter duration. Finally, comparison of the PD/PK profiles of the orally administered aspart-insulin with those of the SC injection of NPH-insulin, an intermediate-acting insulin preparation, suggests the suitability of our NP system to be used as a non-invasive alternative for the basal insulin therapy.

Sistemas de Liberação de Medicamentos/métodos , Insulina/análogos & derivados , Nanopartículas/química , Administração Oral , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Células CACO-2 , Impedância Elétrica , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/metabolismo , Humanos , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Injeções Subcutâneas , Insulina/administração & dosagem , Insulina/farmacocinética , Insulina/farmacologia , Insulina Aspart , Masculino , Microscopia Confocal , Modelos Animais , Nanopartículas/ultraestrutura , Tamanho da Partícula , Ratos , Ratos Wistar , Fatores de Tempo , Distribuição Tecidual/efeitos dos fármacos