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1.
J Environ Sci (China) ; 140: 230-241, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38331503

RESUMO

Cigarette butts (CBs) are one of the most common types of litter in the world. Due to the toxic substances they contain, the waste generated poses a harmful risk to the environment, and therefore there is an urgent need for alternative solutions to landfill storage. Thus, this work presents a possible revalorization of this waste material, which implies interesting environmental benefits. CBs were used as sacrificial templates for the preparation of CaO-based materials by impregnation with calcium and magnesium nitrates followed by flaming combustion. These materials presented enhanced porosity for their use in the Calcium Looping process applied either to thermochemical energy storage or CO2 capture applications. The influence of the concentration of Ca and Mg in the impregnating solutions on the multicycle reactivity of the samples was studied. An improved multicycle performance was obtained in terms of conversion for both applications.


Assuntos
Dióxido de Carbono , Produtos do Tabaco , Dióxido de Carbono/química , Cálcio , Resíduos , Fenômenos Físicos
2.
Rev Enferm ; 40(4): 20-6, 2017 Apr.
Artigo em Espanhol | MEDLINE | ID: mdl-30277706

RESUMO

Objective: To design an instrument to measure impairment of skin integrity in the diaper area of infants and severity of injury for the prevention and management of irritative diaper dermatitis. Methodology: Design in 3 phases: 1) comprehensive review and critical appraisal of literature to design the preliminary content of the instrument; 2) critical evaluation of initial proposal by an expert group (nursing and pediatric medicine) with opinion survey and ad hoc questions; 3) content analysis using data tabulation for the modification and final design of the instrument. Setting: Primary Care Management of Tenerife. Results: In the 1st phase a proposed instrument is designed: two groups of risk factors (10 modulators risk and 9 high risk); and a severity scale with 5 aspects to assess including 4-5 items each (depth, location, extension, type of injury, signs of infection). The 2nd phase involved 19 professionals. A Tabulation of the data grouped into add or omit factors was used. The 3rd phase ends with a modified version of the instrument: 10 modulating factors, 5 of hig risk and 4 items for each aspect to assess severity. Discussion-Conclusions: The scarce bibliography found and absence of similar tools explain the design. The next phase will be the validation of RDIC-lac instrument. Clinical Relevance: Susceptibility to prevent skin lesions in the diaper area in the pediatric age.


Assuntos
Dermatite das Fraldas/diagnóstico , Medição de Risco , Índice de Gravidade de Doença , Humanos , Lactente , Inquéritos e Questionários
3.
Biomedicines ; 12(6)2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38927379

RESUMO

The variability of the Conditioned Pain Modulation (CPM) effect can be attributed to conditioning stimulus (CS) characteristics, such as intensity, duration, unpleasantness, or affinity. This study investigates the impact of affinity and unpleasantness variables on the CPM effect using two protocols (cold water and ischemia) in the same healthy individuals (n = 54). Additional variables were also examined for their potential influence on the CPM effect. The main results are as follows: (1) a higher level of affinity and a lower level of unpleasantness for the stimuli used resulted in a stronger CPM effect; (2) significant differences were observed in the extreme categories (high and low) of both variables, whereas the 'indifferent' group did not show a clear trend; (3) within-subject analysis demonstrated that affinity for the CS had a clear impact on the CPM effect; (4) no correlations were found between the CPM effect and the additional variables, except for the extraversion variable with the CPM effect of the ischemia protocol, and CS duration variable with CPM effect in the cold water protocol; and (5) only the affinity variable explained the CPM effect in both protocols in the multiple linear regression analysis. The affinity variable was found to influence the CPM effects significantly, indicating its important role in our perception and response to pain.

4.
Front Epidemiol ; 4: 1368675, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38952354

RESUMO

Background: Multiple Sclerosis (MS) is a common neurological disease among white populations of European origin. Frequencies among Latin Americans continue to be studied, however, epidemiologic, and clinical characterization studies lack from Central American and Caribbean countries. Ethnicity in these countries is uniformly similar with a prevalent Mestizo population. Methods and results: Data from January 2014 to December 2019 from Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, Dominican Republic, and Aruba on demographic, clinical, MRI and phenotypic traits were determined in coordinated studies: ENHANCE, a population-based, retrospective, observational study on incidence and clinical characteristics, and from the subgroup with MS national registries (Aruba, Dominican Republic, Honduras, and Panama), data on prevalence, phenotypes and demographics. Expanded Disability Status Scale (EDSS), and therapeutic schemes were included. ENHANCE data from 758 patients disclosed 79.8% of Mestizo ethnicity; 72.4% female; median age at onset 31.0 years and 33.2 at diagnosis. The highest incidence rate was from Aruba, 2.3-3.5 × 100,000 inhabitants, and the lowest, 0.07-0.15 × 100,000, from Honduras. Crude prevalence rates per 100,000 inhabitants fluctuated from 27.3 (Aruba) to 1.0 (Honduras). Relapsing MS accounted for 87.4% of cases; EDSS <3.0 determined in 66.6% (mean disease duration: 9.1 years, SD ± 5.0); CSF oligoclonal bands 85.7%, and 87% of subjects hydroxyvitamin D deficient. Common initial therapies were interferon and fingolimod. Switching from interferon to fingolimod was the most common escalation step. The COVID-19 pandemic affected follow-up aspects of these studies. Conclusion: This is the first study providing data on frequencies and clinical characteristics from 8 countries from the Central American and Caribbean region, addressing MS as an emergent epidemiologic disorder. More studies from these areas are encouraged.

5.
Polymers (Basel) ; 15(21)2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-37959944

RESUMO

This study investigates the viability of cinnamic acid derivatives as alternative plasticizers for polyvinyl chloride (PVC) films by addressing concerns about conventional phthalate-based options that pose health and environmental risks. By theoretical modeling, this research evaluates the compatibility between various cinnamic acid-based plasticizers and the PVC matrix, which suggests their potential effectiveness. Additionally, the incorporation of these plasticizers notably enhances the tensile properties of PVC films, particularly in terms of ductility and elongation at break by surpassing the neat PVC. Moreover, cinnamic acid-based plasticizers induce a drop in the glass transition temperature and storage modulus by, thereby, enhancing flexibility and reducing brittleness in the material. Although a slight reduction in the onset degradation temperature is observed, it does not impede the industrial processing of PVC plastisols at temperatures up to 190 °C. Optically, plasticized films exhibit high transparency with minimal UV and visible light absorption, which renders them suitable for applications necessitating clarity. The water vapor transmission rate analysis indicates increased permeability, influenced by molecular volumes. Atomic force microscopy reveals a compacted, homogeneous surface structure in most plasticized films, which signifies improved film quality. Thus, utilizing cinnamic acid derivatives as PVC plasticizers offers substantial mechanical and structural benefits, while compatibility ensures effective integration by contributing to environmentally sustainable PVC formulations with enhanced performance.

6.
Polymers (Basel) ; 15(23)2023 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-38231960

RESUMO

New composite materials were developed with poly(lactide) (PLA) and Posidonia oceanica fibers through reactive extrusion in the presence of dicumyl peroxide (DCP) and subsequent injection molding. The effect of different amounts of methyl trans-cinnamate (MTC) on the mechanical, thermal, thermomechanical, and wettability properties was studied. The results showed that the presence of Posidonia oceanica fibers generated disruptions in the PLA matrix, causing a decrease in the tensile mechanical properties and causing an impact on the strength due to the stress concentration phenomenon. Reactive extrusion with DCP improved the PO/PLA interaction, diminishing the gap between the fibers and the surrounding matrix, as corroborated by field emission scanning electron microscopy (FESEM). It was observed that 20 phr (parts by weight of the MTC, per one hundred parts by weight of the PO/PLA composite) led to a noticeable plasticizing effect, significantly increasing the elongation at break from 7.1% of neat PLA to 31.1%, which means an improvement of 338%. A considerable decrease in the glass transition temperature, from 61.1 °C of neat PLA to 41.6 °C, was also observed. Thermogravimetric analysis (TGA) showed a loss of thermal stability of the plasticized composites, mainly due to the volatility of the cinnamate ester, leading to a decrease in the onset degradation temperature above 10 phr MTC.

7.
Polymers (Basel) ; 15(12)2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37376389

RESUMO

In this study, a new composite material is developed using a semi bio-based polypropylene (bioPP) and micronized argan shell (MAS) byproducts. To improve the interaction between the filler and the polymer matrix, a compatibilizer, PP-g-MA, is used. The samples are prepared using a co-rotating twin extruder followed by an injection molding process. The addition of the MAS filler improves the mechanical properties of the bioPP, as evidenced by an increase in tensile strength from 18.2 MPa to 20.8 MPa. The reinforcement is also observed in the thermomechanical properties, with an increased storage modulus. The thermal characterization and X-ray diffraction indicate that the addition of the filler leads to the formation of α structure crystals in the polymer matrix. However, the addition of a lignocellulosic filler also leads to an increased affinity for water. As a result, the water uptake of the composites increases, although it remains relatively low even after 14 weeks. The water contact angle is also reduced. The color of the composites changes to a color similar to wood. Overall, this study demonstrates the potential of using MAS byproducts to improve their mechanical properties. However, the increased affinity with water should be taken into account in potential applications.

8.
Cir Esp (Engl Ed) ; 101(9): 624-631, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37119950

RESUMO

INTRODUCTION: The standard treatment for intrahepatic cholangiocarcinoma (iCCA) and mixed hepatocellular-cholangiocarcinoma (HCC-CC) is surgical resection, nevertheless, recent studies show adequate survival rates in selected patients with iCCA or HCC-CC undergoing liver transplantation (LT). METHODS: A retrospective cohort study was design including all patients undergoing LT at our center between January, 2006 and December, 2019 with incidentally diagnosed iCCA or HCC-CC after pathological examination of the explanted liver (n = 13). RESULTS: There were no iCCA or HCC-CC recurrences during the follow-up, and hence, there were no tumor related deaths. Global and disease-free survival were the same. The 1, 3 and 5-years patient survival were 92.3%, 76.9% and 76.9%, respectively. Survival rates in the "early-stage tumor group" at 1, 3 and 5 years were 100%, 83.3% and 83.3%, respectively, with no significant differences as compared to the "advanced-stage tumors group". No statistically significant differences in terms of 5-year survival were found when comparing tumor histology (85.7% for iCCA and 66.7% for HCC-CC). CONCLUSIONS: These results suggest that LT could be an option in patients with chronic liver disease who develop an iCCA or HCC-CC, even in highly selected advanced tumors, but we must be cautious when analyzing these results because of the small sample size of the series and its retrospective nature.


Assuntos
Neoplasias dos Ductos Biliares , Carcinoma Hepatocelular , Colangiocarcinoma , Neoplasias Hepáticas , Transplante de Fígado , Humanos , Carcinoma Hepatocelular/cirurgia , Carcinoma Hepatocelular/patologia , Estudos Retrospectivos , Seguimentos , Neoplasias Hepáticas/cirurgia , Neoplasias Hepáticas/patologia , Transplante de Fígado/métodos , Resultado do Tratamento , Neoplasias dos Ductos Biliares/diagnóstico , Colangiocarcinoma/cirurgia , Ductos Biliares Intra-Hepáticos/patologia
10.
ACS Sustain Chem Eng ; 10(2): 850-859, 2022 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-35070518

RESUMO

This study explores the effect of steam addition during carbonation on the multicyclic performance of limestone under calcium looping conditions compatible with (i) CO2 capture from postcombustion gases (CCS) and with (ii) thermochemical energy storage (TCES). Steam injection has been proposed to improve the CO2 uptake capacity of CaO-based sorbents when the calcination and carbonation loops are carried out in CCS conditions: at moderate carbonation temperatures (∼650 °C) under low CO2 concentration (typically ∼15% at atmospheric pressure). However, the recent proposal of calcium-looping as a TCES system for integration into concentrated solar power (CSP) plants has aroused interest in higher carbonation temperatures (∼800-850 °C) in pure CO2. Here, we show that steam benefits the multicyclic behavior in the milder conditions required for CCS. However, at the more aggressive conditions required in TCES, steam essentially has a neutral net effect as the CO2 uptake promoted by the reduced CO2 partial pressure but also is offset by the substantial steam-promoted mineralization in the high temperature range. Finally, we also demonstrate that the carbonation rate depends exclusively on the partial pressure of CO2, regardless of the diluting gas employed.

11.
Healthcare (Basel) ; 10(3)2022 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-35326899

RESUMO

(1) Background: Behavioral and psychological symptoms of dementia (BPSD) are a threat for people with dementia and their caregivers. Doll therapy is a non-pharmacological person-centered therapy to promote attachment, company, and usefulness with the aim of minimizing challenging behaviors. However, the results are not clear. (2) Objective: To know the effectiveness of doll therapy in reducing behavioral and psychological symptoms of people with dementia at a moderate-severe phase. (3) Methodology: The systematic review was informed according to the criteria established by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Searches were conducted in eight databases: Cochrane, PubMed, Web of Science, Cinahl, Embase, Lilacs, PeDro, and Scopus before October 2021. Studies were selected when they accomplished the simple majority of Consolidated Standards of Reporting Trials (CONSORT). The risk of bias was appraised with the Cochrane Collaboration Risk of Bias Tool. The review protocol was recorded in Inplasy:1539. (4) Results: The initial search strategy showed 226 relevant studies, 7 of which met the eligibility criteria. In the included studies, a total number of 295 participants (79% female) with a mean age of 85 years were enrolled. There was found to be a reduction in challenging and aggressive behaviors, the participants were less rough and irritable, and their communication skills and emotional state were also improved. (5) Conclusion: Our findings suggest that doll therapy improves the emotional state of people with dementia, diminishes disruptive behaviors, and promotes communication. However, randomized studies with a larger sample size and higher methodological rigor are needed, as well as follow-up protocols in order to reaffirm these results.

12.
Animals (Basel) ; 11(4)2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33915793

RESUMO

Currently, there is an intense effort to find an alternative hormone to eCG to induce ovulation after estrus synchronization treatments in sheep. One of the proposed alternatives is based on the use of hCG, but the results are controversial since fertility rates are commonly affected. The present study aims to evaluate, therefore, the adequacy of hCG in protocols for the synchronization of estrus and ovulation. Ovarian follicle dynamics, occurrence of estrus behavior and subsequent ovulation, quality of corpora lutea, and pregnancy rate after controlled natural mating were assessed in two consecutive trials. The findings indicate that the low fertility rates reported for the protocols based on the administration of hCG for inducing ovulation during estrus synchronization in sheep may be related to a high occurrence of abnormal follicular growth patterns, disturbances, and retardments of ovulation and concomitant formation of follicular cysts in the treated females. These results preclude their practical application to induce ovulation concomitantly to estrous synchronization treatments.

13.
Urol Int ; 84(3): 292-300, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20389158

RESUMO

OBJECTIVE: To characterize a large series of renal cell carcinomas (RCCs) in young patients and to compare the data obtained to previously published data. PATIENTS AND METHODS: A total of 130 RCCs diagnosed in patients <40 years of age were collected from 9 different hospitals in Spain. Cases were re-evaluated following the diagnostic criteria of the 2004 WHO classification of renal tumors. RESULTS: Histologically, tumors were classified as clear cell (50.7%), papillary (8.5%), chromophobe (14.6%), unclassified (16.9%) and clear cell papillary (9.3%) RCCs. Organ-confined disease (OCD) was detected in 83.6% of the cases. Tumor size and Fuhrman's grade were statistically correlated (Spearman's rho = 0.391). CD10 (p = 0.000), CK7 (p = 0.000), CD15 (p = 0.016), CD117 (p = 0.000), 34betaE12 cytokeratin (p = 0.034) and e-cadherin (p = 0.000) immunostaining significantly differentiated the five histological categories. CONCLUSIONS: OCD was more common in young RCC patients. The clear cell phenotype accounted for only 50% of RCCs in this age group, with an increasing number of chromophobe and unclassified RCCs. Clear cell RCCs with a papillary growth pattern accounted for a significant proportion of the cases.


Assuntos
Carcinoma de Células Renais/patologia , Neoplasias Renais/patologia , Adolescente , Adulto , Feminino , Humanos , Imuno-Histoquímica , Masculino , Estudos Retrospectivos , Adulto Jovem
14.
J Colloid Interface Sci ; 561: 678-686, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31761465

RESUMO

In this work, we utilize a top-down approach to synthesize nitrogen doped graphene quantum dots from a 3D-graphene precursor via an eco-friendly hydrothermal method. The nanoparticles obtained showed a 2-3 nm diameter and well dispersion behavior in aqueous media. The reaction mechanism of insertion of nitrogen from polyvinylpolypyrrolidone onto the 3D-graphene structure, via an esterification reaction, was studied by the density functional theory, in addition, the kinetic and thermodynamic magnitudes of the reaction was analyzed with the help of Eyring's transition state theory and statistical thermodynamics. After analysis by ss-NMR and XPS spectroscopies, the functional groups involved in this process were characterized, and N was found mainly as amide/amine groups. Fluorescence emission, which exhibited a red shift (552 nm) and an emission maximum at 512 nm when excited at 480 nm, demonstrated a low stoke shift (Δλ = 32 nm), explained by the proposed structural model.

15.
Anal Chim Acta ; 1050: 169-175, 2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30661586

RESUMO

Analytical nanometrology is a present challenge in today's analytical science, particularly from a practical point of view and when it is addressed to routine/control laboratories. In this way, a screening-confirmation approach is described for the characterization and distinction between titanium dioxide nano/micro-particles in sugary food samples. The first step involves the confirmation of the presence of TiO2 in the sample (used as additive E171 in sugary samples), using a portable Raman spectrometer, in which the crystalline structure of TiO2 (anatase or rutile) in the positive samples can be also obtained in this step. Then, the second step was only applied to positive samples, and it involves the use of Capillary Electrophoresis (CE), which allows to distinguish between TiO2-nanoparticles (<100 nm) from TiO2-microparticles (>100 nm). Additionally, nanoparticles (TiO2 anatase (5 nm diameter) and TiO2 rutile (60 nm diameter) and rutile microparticles (0.1-0.2 µm diameter) can be electrophoretically separated. The general procedure is simple, fast, and low cost, providing a valuable analytical tool in the field of food safety and control, thus contributing to the development of the analytical nanometrology.


Assuntos
Nanopartículas/química , Nanotecnologia , Açúcares/química , Titânio/química , Eletroforese Capilar , Conformação Molecular , Análise Espectral Raman
16.
Talanta ; 194: 357-362, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30609543

RESUMO

The fabrication of surface-enhanced Raman spectroscopy (SERS) substrates, which can offer the advantages of strong Raman signal enhancement with good reproducibility, is still a challenge for practical applications. In this work, a simple and reproducible SERS substrate combining the properties of multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs), is proposed for the determination and quantification of sulfapyridine in milk samples with a concentration range of 10-100 ng mL-1. The Raman signals of sulfapyridine is enhanced at factor of 4394. The procedure presented is capable of detecting and quantifying small quantities of sulfapyridine without implying any preconcentration step, just using an affordable and portable Raman spectrometer. The precision, in terms of repeatability and inter and intermediate precision, was lower than 8% in all cases.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Leite/química , Nanotubos de Carbono/química , Análise Espectral Raman/métodos , Sulfapiridina/análise , Animais , Propriedades de Superfície , Fatores de Tempo
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 223: 117302, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31260886

RESUMO

A novel approach for the decoration of reduced graphene oxide with copper selenide (CuSe-rGO), using supercritical carbon dioxide (sc-CO2) as a medium, was developed and proposed as a new substrate for surface-enhanced Raman spectroscopy (SERS) to determine Rhodamine B in chili powder. The synthesized materials graphene oxide (GO), reduced graphene oxide (rGO) and CuSe-rGO were characterized by Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). All SERS spectra were obtained by using a portable Raman spectrometer. The procedure presented involves a simple and rapid sample pretreatment in order to determine Rhodamine B in chili powder, with a limit of quantification of 44.5 ng g-1. The recovery values of the proposed method resulted in the 96% to 99% range, with RSD values from 2.4% to 3.0%. The developed SERS active hybrid substrate has an enhancement factor higher than those using gold or silver nanoparticles, providing a clear improvement in the sensitivity.

18.
Hear Res ; 213(1-2): 1-10, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16386394

RESUMO

In teleosts, the lateral line system is composed of neuromasts containing hair cells that are analogous to those present in the inner ear of all vertebrates. In the zebrafish embryo and early larva, this system is composed of the anterior lateral line (ALL), which covers the head, and the posterior lateral line (PLL), present in the trunk and tail. The mechanosensory hair cells found in neuromasts can be labeled in vivo using fluorescent dyes such as 4-di-2-Asp (DiAsp) or FM1-43. We have studied the effects of water-borne copper exposure on the function of the lateral line system in zebrafish larvae. Our results show that transient incubation of post-hatching larvae for 2h with non-lethal concentrations of copper (1-50 microM CuSO4) induces cellular damage localized to neuromasts, apoptosis, and loss of hair cell markers. This effect is specific to copper, as other metals did not show these effects. Since hair cells in fish can regenerate, we followed the reappearance of viable hair cells in neuromasts after copper removal. In the PLL, we determined that there is a threshold concentration of copper above which regeneration does not occur, whereas, at lower concentrations, the length of time it takes for viable hair cells to reappear is dependent on the amount of copper used during the treatment. The ALL behaves differently though, as regeneration can occur even after treatments with concentrations of copper an order of magnitude higher than the one that irreversibly affects the PLL. Regeneration of hair cells is dependent on cell division within the neuromasts as damage that precludes proliferation prevents reappearance of this cell type.


Assuntos
Cobre/toxicidade , Sistema da Linha Lateral/efeitos dos fármacos , Mecanorreceptores/efeitos dos fármacos , Animais , Morte Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Células Ciliadas Auditivas/efeitos dos fármacos , Imuno-Histoquímica , Sistema da Linha Lateral/citologia , Mecanorreceptores/fisiologia , Compostos de Piridínio , Regeneração , Coloração e Rotulagem , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
19.
Acta Psychol (Amst) ; 123(3): 279-98, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16524555

RESUMO

Some contemporary approaches suggest that inhibitory mechanisms play an important role in cognitive development. In addition, several authors distinguish between intentional and unintentional inhibitory processes in cognition. We report two experiments aimed at exploring possible developmental changes in these two types of inhibitory mechanisms. In Experiment 1, an updating task was used. This task requires that participants intentionally suppress irrelevant information from working memory. In Experiment 2, the retrieval-practice task was used. Retrieval practice of a subset of studied items is thought to involve unintentional inhibitory processes to overcome interference from competing memories. As a result, suppressed items become forgotten in a later memory test. Results of the experiments indicated that younger children (8) were less efficient than older children (12) and adults at intentionally suppressing information (updating task). However, when the task required unintentional inhibition of competing items (retrieval-practice task), this developmental trend was not found and children and adults showed similar levels of retrieval-induced forgetting. The results are discussed in terms of the development of efficient inhibition and the distinction between intentional and unintentional inhibitions.


Assuntos
Cognição/fisiologia , Memória/fisiologia , Adolescente , Fatores Etários , Criança , Feminino , Humanos , Masculino , Rememoração Mental , Vocabulário
20.
Talanta ; 161: 775-779, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27769480

RESUMO

A supercritical carbon dioxide medium was used for the decoration of functionalized multi-walled carbon nanotubes (MWCNTs) with metallic nanoparticles. This procedure allowed the rapid and simple decoration of carbon nanotubes with the selected metallic nanoparticles. The prepared nanomaterials were used to modify screen-printed electrodes, improving their electrochemical properties and allowing to obtain a wide range of working electrodes based on carbon nanotubes. These electrodes were applied to the amperometric determination of vitamin B6 in food and pharmaceutical samples as an example of the analytical potentiality of the electrodes thus prepared. Using Ru-nanoparticles-MWCNTs as the working electrode, a linear dynamic range between 2.6×10-6 and 2×10-4molL-1 and a limit of detection of 0.8×10-6molL-1 were obtained. These parameters represented a minimum 3-fold increase in sensitivity compared to the use of bare MWCNTs or other carbon-based working electrodes.

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