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1.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-38575067

RESUMO

OBJECTIVE: The aim of this review is to summarize the current evidence and future perspectives of bladder-sparing treatment for MIBC. METHODS: A non-systematic literature search in Medline/Pubmed was performed in October 2023 with the following keywords "bladder cancer", "bladder-sparing", "trimodal therapy", "chemoradiation", "biomarkers", "immunotherapy", "neoadjuvant chemotherapy", "radiotherapy". RESULTS: Urology guidelines recommend radical cystectomy as the standard curative treatment for muscle-invasive urothelial bladder cancer, reserving radiotherapy for patients who are unfit or who want to preserve their bladder. Given the morbidity and mortality of cystectomy and its impact on quality of life and bladder function, modern oncologic therapies are increasingly oriented toward organ preservation and maximizing functional outcomes while maintaining treatment efficacy. Trimodal therapy, which incorporates maximal transurethral resection followed by radiotherapy with concurrent radiosensitizing chemotherapy, is an effective regimen for bladder function preservation in well-selected patients. Despite the absence of comparative data from randomized trials, the two approaches seem to provide comparable oncologic outcomes. Studies are evaluating the expansion of eligibility criteria for trimodal therapy, the optimization of radiotherapy and immunotherapy delivery to further improve outcomes, and the validation of biomarkers to guide bladder preservation. CONCLUSIONS: Trimodal therapy has shown acceptable outcomes for bladder preservation; therefore, it provides a valid treatment option in well-selected patients.

2.
Food Chem ; 444: 138709, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38350163

RESUMO

Melon landraces are highly appreciated by consumers who pay price premiums to compensate for lower yields, enabling on-farm conservation. However, they are highly susceptible to soilborne diseases. This study analyses the impact of Cucurbita and Cucumis rootstocks on the accumulation of flavor-related metabolites in Spanish landraces of the Ibericus melon group, as a strategy to promote their sustainable cultivation. Scion genotype was the main factor conditioning the accumulation of sugars and acids both under standard and saline organic farming conditions. The effects of grafting on organic acid accumulation were negligible, while the effects on sugar content were significant. The latter effects were dependent on specific scion-rootstock combinations, though wild Cucumis (e.g. Fian) rootstocks represent an alternative that should be further studied. The effect on the accumulation of volatiles was limited, and again depended on specific scion-rootstock combinations. The rootstock effect even differed between populations of the same landrace.


Assuntos
Cucumis , Cucurbita , Cucurbitaceae , Agricultura , Açúcares , Ácidos
3.
Phys Chem Chem Phys ; 19(34): 22670-22677, 2017 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-28812086

RESUMO

The photoluminescence behaviour of carbon-based nanodots is still debated. Both core and surface structures are involved in the emission mechanism, and the electronic transitions can be modified by external agents such as metal ions or pH, but the general relation between the structure and the optical function is poorly understood. Here, we report a comparative study on the effects of these variables, changing the core structure from crystalline to amorphous, and modifying the surface structure by different passivation procedures. Our results highlight that the emission mechanism of the tunable visible fluorescence is identical for crystalline and amorphous samples, indicating the independence of the emission from the core structure. Furthermore, surface functionalization weakly influences the emission peak position, but has large consequences on their interaction with different metal ions. This suggests the involvement of quasi-degenerate electronic states originating from the high density of different interacting groups on the surface. Finally, we report the presence of an unusual ultraviolet emission band for the amorphous sample, likely involving localized molecular-type chromophores with carboxyl ends. Our findings provide new information on the emission mechanisms of CDs and can be used to engineer sub-types of CDs displaying very similar emission features, but specifically tailored for different sensing applications.

4.
Int J Med Inform ; 103: 55-64, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28551002

RESUMO

INTRODUCTION: Hyponatremia is the most common type of electrolyte imbalance, occurring when serum sodium is below threshold levels, typically 135mmol/L. Electrolyte balance has been identified as one of the most challenging subjects for medical students, but also as one of the most relevant areas to learn about according to physicians and researchers. We present a computer-interpretable guideline (CIG) model that will be used for medical training to learn how to improve the diagnosis of hyponatremia applying an expert consensus document (ECDs). METHODS: We used the PROForma set of tools to develop the model, using an iterative process involving two knowledge engineers (a computer science Ph.D. and a preventive medicine specialist) and two expert endocrinologists. We also carried out an initial validation of the model and a qualitative post-analysis from the results of a retrospective study (N=65 patients), comparing the consensus diagnosis of two experts with the output of the tool. RESULTS: The model includes over two-hundred "for", "against" and "neutral" arguments that are selectively triggered depending on the input value of more than forty patient-state variables. We share the methodology followed for the development process and the initial validation results, that achieved a high ratio of 61/65 agreements with the consensus diagnosis, having a kappa value of K=0.86 for overall agreement and K=0.80 for first-ranked agreement. CONCLUSION: Hospital care professionals involved in the project showed high expectations of using this tool for training, but the process to follow for a successful diagnosis and application is not trivial, as reported in this manuscript. Secondary benefits of using these tools are associated to improving research knowledge and existing clinical practice guidelines (CPGs) or ECDs. Beyond point-of-care clinical decision support, knowledge-based decision support systems are very attractive as a training tool, to help selected professionals to better understand difficult diseases that are underdiagnosed and/or incorrectly managed.


Assuntos
Simulação por Computador , Tomada de Decisões Assistida por Computador , Sistemas de Apoio a Decisões Clínicas , Hiponatremia/diagnóstico , Guias de Prática Clínica como Assunto/normas , Idoso , Consenso , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Estudos Retrospectivos , Software
5.
Rev Neurol ; 63(s01): S13-S18, 2016 Sep 05.
Artigo em Espanhol | MEDLINE | ID: mdl-27658431

RESUMO

INTRODUCTION: The effectiveness and safety of fingolimod in patients with relapsing-remitting multiple sclerosis (RRMS) have been proven in clinical trials. Yet, due to their limitations, it is important to know how it behaves under everyday clinical practice conditions. Hence, the aim of this study is to evaluate the effectiveness and safety of fingolimod after 12 months' usage in clinical practice in Galicia. PATIENTS AND METHODS: We conducted a retrospective, multi-centre study (n = 8) of patients with RRMS who were treated with one or more doses of fingolimod, 0.5 mg/day. Effectiveness was assessed -annualised relapse rate (ARR), changes in the score on the Expanded Disability Status Scale (EDSS), percentage of patients free from relapses, free from progression of disability and free from activity in resonance- for the total number of patients and according to previous treatment. Safety was assessed based on the percentage of patients who withdrew and presented adverse side effects. RESULTS: After 12 months' use, fingolimod reduced the ARR by 87% (1.7 to 0.23; p < 0.0001) and, consequently, 81% of patients were free from relapses. The score was reduced by 9%. In all, 91% of patients were free from progression of disability and 72% were free from resonance activity. No signs of disease activity were found in 43% of the patients. Most of the benefits of fingolimod differed depending on previous treatment. About a third of the patients reported adverse side effects, but only 2% of them withdrew for this reason. CONCLUSIONS: In clinical practice, most of the results on the effectiveness of the clinical trials conducted with fingolimod were observed during the first 12 months of treatment. A better safety profile was observed than that reported in the clinical trials.


TITLE: Fingolimod: efectividad y seguridad en la practica clinica habitual. Estudio observacional, retrospectivo y multicentrico en Galicia.Introduccion. La efectividad y seguridad del fingolimod en pacientes con esclerosis multiple remitente recurrente (EMRR) se demostro en ensayos clinicos. Sin embargo, por las limitaciones de estos, es importante saber como se comporta en condiciones de practica clinica habitual. Asi, el objetivo de este estudio es evaluar la efectividad y seguridad del fingolimod despues de 12 meses de uso en la practica clinica en Galicia. Pacientes y metodos. Estudio retrospectivo y multicentrico (n = 8) de pacientes con EMRR y tratados con una o mas dosis de fingolimod, 0,5 mg/dia. Se evaluo la efectividad ­tasa anualizada de brotes (TAB), cambio en la puntuacion de la escala expandida del estado de discapacidad (EDSS), porcentaje de pacientes libres de brotes, libres de progresion de discapacidad y libres de actividad en resonancia­ para el total de pacientes y segun tratamiento previo. Se evaluo la seguridad a partir del porcentaje de pacientes que discontinuaron y que presentaron efectos adversos. Resultados. Despues de 12 meses de uso, el fingolimod redujo un 87% la TAB (de 1,7 a 0,23; p < 0,0001) y, en consecuencia, un 81% de pacientes estuvo libre de brotes. La puntuacion de la EDSS disminuyo un 9%. Un 91% de pacientes estuvo libre de progresion de discapacidad y un 72%, libre de actividad en resonancia. En el 43% de los pacientes no se evidenciaron signos de la actividad de la enfermedad. La mayoria de los beneficios del fingolimod difirieron segun el tratamiento previo. Alrededor de un tercio de los pacientes comunicaron efectos adversos, pero solo el 2% discontinuo debido a ellos. Conclusiones. La mayoria de los resultados de efectividad de los ensayos clinicos del fingolimod se observa durante los 12 primeros meses de tratamiento en la practica clinica. Se observo un mejor perfil de seguridad al comunicado en los ensayos clinicos.

6.
J Chromatogr A ; 1464: 42-9, 2016 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-27558356

RESUMO

In this article, carbon fibres (CFs) are presented as sorbent material for the dispersive micro-solid phase extraction of twelve chlorophenols from urine samples. CFs are synthesized by a reagentless and green procedure consisting of heating raw cotton, a natural precursor, at high temperature (400°C) in an inert atmosphere (Ar) during 2h. The resulting fibres, which present good water dispersibility, are finally loaded on an in-syringe device. This device, which integrates the extraction and final elution of the analytes, is disposable and it is adapted to process low sample volumes. Working at the optimum conditions, the extraction procedure in combination with gas chromatography/mass spectrometry allows the determination of the analytes in urine at the low µg/L range. In fact, the limits of quantification (LOQs) of the analytes were in the interval from 1µg/L to 2.5µg/L with precision values, expressed as relative standard deviations (RSD), better than 13%. Relative recovery values, ranging from 74.5% to 113%, demonstrate the applicability of the proposed method.


Assuntos
Clorofenóis/isolamento & purificação , Clorofenóis/urina , Cromatografia Gasosa-Espectrometria de Massas/métodos , Extração em Fase Sólida/métodos , Carbono/química , Fibra de Carbono , Humanos , Extração em Fase Sólida/instrumentação , Seringas
7.
Analyst ; 141(9): 2688-95, 2016 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-27055393

RESUMO

This work presents a novel fluorescent sensor for the determination of tacrine by combining the magnificent fluorescence properties of nitrogen-doped graphene quantum dots (N-GQDs) with the high potential of acetylcholinesterase (AChE) enzyme for screening its inhibitors. Tacrine was the first drug approved for Alzheimer's disease and it is currently being used in several therapeutic treatments given its activity as a reversible inhibitor of AChE. The principle of the developed biosensor relies on the fact that the native fluorescence of the synthesized N-GQDs is quenched by interaction with enzymatic reaction products, and the inclusion of tacrine in assay solution results in the gradual recovery of the original fluorescence in an inhibitor concentration-dependent manner. While N-GQD fluorescence was not directly affected by tacrine, the inclusion of an AChE based-enzymatic system allowed for its determination with a detection limit (S/N = 3) of 1.22 µM. This biosensor was demonstrated to be simple, rapid and reproducible (%RSD 4.87, n = 7) for analysis of tacrine in aqueous solutions.


Assuntos
Acetilcolinesterase/química , Técnicas Biossensoriais/tendências , Grafite/química , Nitrogênio/química , Pontos Quânticos/química , Tacrina/análise , Técnicas Biossensoriais/métodos
8.
Talanta ; 151: 100-105, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-26946015

RESUMO

The paper reports for the first time the direct determination of silver ion (Ag(+)) using luminescent Carbon Quantum Dot hydrogels (CQDGs). Carbon Quantum Dots (CQDs) with different superficial moieties (passivate-CQDs with carboxylic groups, thiol-CQDs and amine-CQDs) were used to prepare hybrid gels using a low molecular weight hydrogelator (LMWG). The use of the gels results in considerable fluorescence enhancement and also markedly influences selectivity. The most selective CQDG system for Ag(+) ion detection proved to be those containing carboxylic groups onto their surface. The selectivity towards Ag(+) ions is possibly due to its flexible coordination sphere compared with other metal ions. This fluorescent sensing platform is based on the strong Ag-O interaction which can quench the photoluminescence of passivate-CQDs (p-CQDs) through charge transfer. The limit of detection (LOD) and quantification (LOQ) of the proposed method were 0.55 and 1.83µgmL(-1), respectively, being applied in river water samples.

9.
J Chromatogr A ; 1431: 55-63, 2016 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-26792452

RESUMO

UV-ion mobility spectrometry (UV-IMS) is a reliable and inexpensive technique which allows efficient monitoring of BTX (benzene, toluene, m-xylene, o-xylene and p-xylene) in different air samples. Water molecules are unavoidably present in every on-field measurement affecting sensitivity and selectivity of the UV-IMS method. For this reason, the influence of humidity on the mobility spectra when measuring BTX is discussed here. Furthermore, a polydimethyl siloxane (PDMS) membrane assembled on an ad-hoc designed membrane holder coupled to UV-IMS was proposed for online measurement of analytes in humid gaseous samples without sample preparation/pre-treatment steps. The use of this membrane reduces the moisture of the gaseous sample before entering into the IMS, and the consequent distortion of the signal. The limit of detection (LOD) and the limit of quantification (LOQ) achieved with the method proposed were in the range of 0.49-1.21mgL(-1) and 1.63-4.03mgL(-1), respectively for all analytes. The precision of the method was evaluated in terms of repeatability and reproducibility obtaining values lower than 1.1% for drift time and 12.0% for peak height when the membrane was used coupled to the UV-IMS for all target analytes in the humidity range of 10-75% RH. Thus, BTX can be determined directly and quantified unequivocally with the membrane system in ambient air even at humid condition.


Assuntos
Monitoramento Ambiental/métodos , Gases/química , Hidrocarbonetos Aromáticos/análise , Análise Espectral , Poluentes Atmosféricos/análise , Benzeno/análise , Umidade , Íons/química , Reprodutibilidade dos Testes , Tolueno/análise , Xilenos/análise
10.
Chem Commun (Camb) ; 52(7): 1311-26, 2016 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-26671042

RESUMO

Fluorescent nanodots have become increasingly prevalent in a wide variety of applications with special interest in analytical and biomedical fields. The present overview focuses on three main aspects: (i) a systematic description and reasonable classification of the most relevant types of fluorescent nanodots according to their nature, quantum confinement and crystalline structure is provided, starting with a clear distinction between semiconductor and carbon-based dots (graphene quantum dots, carbon quantum dots and carbon nanodots). A new set of abbreviations and definitions for them to avoid contradictions found in literature is also proposed; (ii) a rational classification allows the establishment of clear-cut differences and similarities among them. From a basic point of view, the origins of the photoluminescence of the different nanodots are also established, which is a relevant contribution of this overview. Additionally, the most outstanding similarities and differences in a great variety of criteria (i.e. year of discovery, synthesis, the physico-chemical characteristics like structure, nature, shape, size, quantum confinement, toxicity and solubility, the optical characteristics including the quantum yield and lifetime, limitations, applications as well as the evolution of publications) are thoroughly outlined; and (iii) finally, the promising future of fluorescent nanodots in both analytical and biomedical fields is discussed using selected examples of relevant applications.


Assuntos
Carbono/química , Nanoestruturas , Semicondutores , Fluorescência
11.
Case Rep Pediatr ; 2015: 984214, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26576310

RESUMO

Neonatal hyperglycemia is a metabolic disorder found in the neonatal intensive care units. Neonatal diabetes mellitus (NDM) is a very uncommon cause of hyperglycemia in the newborn, occurring in 1 in every 400,000 births. There are two subtypes of neonatal diabetes mellitus: permanent neonatal diabetes mellitus (PNDM) and transient neonatal diabetes mellitus (TNDM). We describe a term, small for gestational age, female neonate with transient neonatal diabetes mellitus who presented with poor feeding tolerance and vomiting associated with hyperglycemia (385 mg/dL), glycosuria, and metabolic acidosis within the first 12 hours of life. The neonate was treated with intravenous insulin, obtaining a slight control of hyperglycemia. An adequate glycemia was achieved at 5 weeks of life. The molecular studies showed complete loss of maternal methylation at the TND differentially methylated region on chromosome 6q24. The etiology of this neonate's hyperglycemia was a hypomethylation of the maternal TND locus. A rare cause of neonatal diabetes mellitus must be considered if a neonate presents refractory hyperglycemia. To our knowledge, this is the first case reported in Puerto Rico of transient neonatal mellitus due to the uncommon mechanism of maternal hypomethylation of the TND locus. Its prevalence in Puerto Rico is unknown.

12.
Talanta ; 144: 944-52, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26452912

RESUMO

The quantitative determination of some compounds such as benzene and phenol in a complex matrix by ion mobility spectrometry (IMS) can be a difficult task, due to the influence of other components present in the matrix and the chemical properties of both compounds, such as their high volatility and low proton affinity. Monitoring of these compounds in a heat transfer fluid (HTF) is essential to check the correct working of a thermosolar plant and for safety and environmental reasons. Benzene and phenol, among other compounds, are produced when HTF is exposed to high temperatures in continuous cycles and their presence can decrease the efficiency of HTF. For the first time, a headspace module coupled to a gas chromatography column in combination with an IMS (with a tritium ionization source) has been optimized and fully validated to simultaneously quantify benzene and phenol in HTF. The limit of detection (LOD) and limit of quantification (LOQ) achieved with the method proposed were 0.011 and 0.038 g L(-1) and 0.004 and 0.014 g L(-1) for benzene and phenol respectively. The precision of the method was evaluated in terms of repeatability and reproducibility with all values lower than 9.2% and 13.3%, respectively. Results demonstrated that benzene and phenol were generated in the HTF heating process, and its concentration increased with heating time (approximately 483 h). The average concentration values for benzene and phenol in degraded HTF samples were not significantly different to values obtained using a gas chromatography-flame ionization detector instrument. Therefore, IMS is a promising technique for in-field quality control of HTF in a thermosolar plant due to its speed, versatility, sensitivity and selectivity to quantify these degradation compounds.

13.
J Chromatogr A ; 1370: 25-32, 2014 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-25454127

RESUMO

A periodic mesoporous organosilica, in particular, a phenylene-bridged material (Ph-PMO), was evaluated for the first time as a sorbent for retaining and eluting fenuron, simazine, atrazine, carbaryl and terbutryn in grape must by solid phase extraction (SPE) prior to their determination with capillary electrophoresis coupled with ultraviolet detection (CE-UV). The analytes were used as model compounds to demonstrate the potential of Ph-PMO for increasing the sensitivity of CE. Under optimal conditions, the limits of detection for the analytes ranged from 0.6 to 4 µg/L, and their limits of quantitation from 2 to 10 µg/L. These values were comparable and, in some cases, even better than those obtained with C18 and HLB materials. Ph-PMO was characterized physicochemically by X-ray diffraction analysis, N2 adsorption-desorption measurements and laser diffraction particle sizing. The sorbent afforded the extraction of atrazine, carbaryl and terbutryn from grape must with mean recoveries ranging from 86 to 105%. Therefore, periodic mesoporous organosilicas possess a high potential as SPE materials.


Assuntos
Dióxido de Silício/química , Extração em Fase Sólida/métodos , Adsorção , Eletroforese Capilar/métodos , Concentração de Íons de Hidrogênio , Tamanho da Partícula , Porosidade , Propriedades de Superfície , Difração de Raios X
14.
J Hazard Mater ; 275: 107-15, 2014 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-24853140

RESUMO

The aim of this study was to assess the toxicological risks arising from the coexistence of polyethylene glycol coated single-walled carbon nanotubes (SWCNTs-PEG) and a known environmental contaminant: 4-nonylphenol (NP). To this end, in vitro toxicity assays involving the exposure of 3T3-L1 cells (mouse embryonic fibroblasts) to SWCNTs-PEG alone or in combination with NP for 24 or 48 h were performed. Experimental treatments were conducted in both presence (10%) and absence of serum in order to evaluate its influence on the toxicity of SWCNTs-PEG. Although the results provided no unambiguous evidences of synergistic toxicity between SWCNTs-PEG and NP, some specific treatments with mixtures (SWCNTs-PEG+NP) resulted in an unexpected combined toxicity in relation to the individual treatments. Only in those cases the interaction between SWCNTs-PEG and NP could have a synergistic effect on the resulting toxicity. The addition of 10% serum increased the stability of SWCNTs-PEG in the culture medium-possibly by steric repulsions-and reduced the toxicity of nanoparticles as a result. Overall, the serum had a "protective effect" on cells against all treatments: SWCNTs-PEG, NP or their mixtures (SWCNTs-PEG+NP). Raman spectroscopy allowed the intracellular distribution of SWCNTs-PEG to be elucidated.


Assuntos
Disruptores Endócrinos/toxicidade , Poluentes Ambientais/toxicidade , Nanotubos de Carbono/toxicidade , Fenóis/toxicidade , Polietilenoglicóis/toxicidade , Soro , Células 3T3-L1 , Animais , Sobrevivência Celular/efeitos dos fármacos , Disruptores Endócrinos/química , Poluentes Ambientais/química , Camundongos , Nanotubos de Carbono/química , Fenóis/química , Polietilenoglicóis/química
15.
J Chromatogr A ; 1345: 43-9, 2014 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-24786654

RESUMO

In this article, the easy synthesis of magnetic nanoparticles-nylon 6 composite is presented, characterized and applied in the microextraction field. The one-step synthesis of the composite is performed by a solvent changeover playing with the different solubility of the polymeric network in formic acid and water. The new material has been characterized by different techniques including infrared spectroscopy, transmission and scanning microscopy. The extraction performance of the composite under a dispersive micro solid phase extraction format has been evaluated by determining four polycyclic aromatic hydrocarbons (benzo[b]fluoranthene, fluoranthene, indeno[1,2,3-cd]pyrene and phenanthrene) in water using ultra performance liquid chromatography (UPLC) combined with photo diode array detection. The developed methodology allows the determination of the analytes with limits of detection in the range from 0.05 µg/L (benzo[b]fluoranthene) to 0.58 µg/L (phenanthrene). The repeatability of the method was better than 6.9% at the limit of quantification level. The relative recoveries varied in the interval 80-111%.


Assuntos
Caprolactama/análogos & derivados , Nanopartículas de Magnetita/química , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Polímeros/química , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/isolamento & purificação , Caprolactama/química , Cromatografia Líquida de Alta Pressão/métodos , Nanopartículas de Magnetita/ultraestrutura , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Hidrocarbonetos Policíclicos Aromáticos/química , Extração em Fase Sólida/instrumentação , Água/química
16.
J Chromatogr A ; 1343: 26-32, 2014 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-24745843

RESUMO

In this article, carbon coated titanium dioxide nanotubes (c-TNTs) have been synthesized. The synthesis of the bare TNTs (b-TNTs) using anatase as precursor and their coating with a caramel layer have been performed by simple and cheap hydrothermal processes. The final conversion of the caramel layer in a carbon coating has been accomplished by a thermal treatment (600°C) in an inert (Ar) atmosphere. The c-TNTs have been characterized by different techniques including transmission microscopy, infrared spectroscopy, X-ray powder diffraction, thermogravimetry and Brunauer, Emmett and Teller (BET) adsorption isotherms. The extraction performance of the c-TNTs under a microextraction format has been evaluated and compared with that provided by b-TNTs and multiwalled carbon nanotubes (MWCNTs) using naproxen and ketoprofen as model analytes. c-TNTs provided better results than the other nanoparticles, especially at low acidic pH values. In addition, c-TNTs presented a better dispersibility than MWCNTs, which is very interesting for their use in dispersive micro-solid phase extraction. Finally, a microextraction format, adapted to low sample volumes, has been proposed and applied for the determination of naproxen and ketoprofen in saliva and urine samples by liquid chromatography with UV detection. The results indicate that this approach is promising for the analysis of biological samples. In fact, the recoveries were in the range between 96% and 119% while the precision, expressed as relative standard deviation, was better than 8.5% and 26.3% for urine and saliva, respectively. The detection limits were in the range 34.1-40.8µg/L for saliva samples and 81.1-110µg/L for urine samples.


Assuntos
Carbono/química , Nanotubos de Carbono/química , Extração em Fase Sólida/métodos , Titânio/química , Adsorção , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Transmissão , Nanopartículas/química , Nanotubos de Carbono/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
17.
Anal Bioanal Chem ; 406(8): 1999-2000, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24481620
18.
Sci Total Environ ; 466-467: 40-6, 2014 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-23892022

RESUMO

The awareness of the impact of human activities in society and environment is known as "Social Responsibility" (SR). It has been a topic of growing interest in many enterprises since the fifties of the past Century, and its implementation/assessment is nowadays supported by international standards. There is a tendency to amplify its scope of application to other areas of the human activities, such as Research, Development and Innovation (R + D + I). In this paper, a model of quantitative assessment of Social Responsibility in Environmental Science and Technology (SR EST) is described in detail. This model is based on well established written standards as the EFQM Excellence model and the ISO 26000:2010 Guidance on SR. The definition of five hierarchies of indicators, the transformation of qualitative information into quantitative data and the dual procedure of self-evaluation and external evaluation are the milestones of the proposed model, which can be applied to Environmental Research Centres and institutions. In addition, a simplified model that facilitates its implementation is presented in the article.


Assuntos
Ecologia , Atividades Humanas , Modelos Teóricos , Responsabilidade Social , Tecnologia , Ecologia/normas , Humanos , Tecnologia/normas
19.
Analyst ; 139(1): 290-8, 2014 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-24255912

RESUMO

Raman spectroscopy has been employed in analytical sciences for purity determination of carbon nanotube samples based on the consideration of G-/D-band intensity ratios. This work demonstrates the role of aggregation in these feature bands, which, in the case of single walled carbon nanotubes (SWNTs), has proved to be crucial for G-/D-band intensity ratio measurements. We have found variation in the relative intensities of G- and D-bands across a sample of SWNTs without any other treatment, discarding the possible influence of the laser beam or sample focusing. In the case of multiwalled carbon nanotubes (MWNTs), this effect is less notorious. Thus, to achieve a good representativeness of Raman measurements, it is important to consider the sample preparation procedure in order to avoid aggregation, which has an effect over the signals, making difficult the subsequent interpretation of results.

20.
Talanta ; 118: 321-7, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24274303

RESUMO

A simple, environmentally friendly, one-pot method to synthesize highly stable bare gold nanoparticles (AuNPs) has been developed. AuNPs have been synthesized from tetrachloroauric acid solution using steel or stainless steel as solid reducing agent, which can be reused. The proposed method yields bare gold nanoparticles at atmospheric pressure and room temperature for potentially producing large quantities. The obtained AuNPs have been characterized by SEM, TEM and AFM finding an average diameter of around 20 nm, polygonal yet nearly spherical shape and a narrow size distribution. The mechanism of reaction has been investigated by UV-vis spectroscopy, ICP-OES and EDX analysis. The obtained dispersed gold nanoparticles proved to be stable if stored a 4 °C for over four months without the addition of a stabilizing agent. Their analytical potential as SERS substrate has been demonstrated and their performance compared with that showed by citrate-coated gold nanoparticles. Thanks to their unique properties, their use as analytical tools provides analytical processes with enhanced selectivity and precision.


Assuntos
Técnicas Biossensoriais/métodos , Ácido Cítrico/química , Ouro/química , Nanopartículas Metálicas/química , Análise Espectral Raman/métodos , Aço Inoxidável/química , Microscopia de Força Atômica/métodos , Microscopia Eletrônica de Varredura/métodos , Microscopia Eletrônica de Transmissão/métodos , Espectrometria por Raios X/métodos , Espectrofotometria Ultravioleta/métodos , Propriedades de Superfície
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