Browsing by Issue Date, starting with "2022-04-06"
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- Electropolymerized, Molecularly Imprinted Polymer on a Screen-Printed Electrode—A Simple, Fast, and Disposable Voltammetric Sensor for TrazodonePublication . Seguro, Isabel; Rebelo, Patrícia; Pacheco, João; Delerue-Matos, CristinaIn recent years, analytical chemistry has been facing new challenges, particularly in developing low-cost, green, and easy-to-reproduce methods. In this work, a simple, reproducible, and low-cost electrochemical (voltammetric) molecularly imprinted polymer (MIP) sensor was designed specifically for the detection of trazodone (TZD). Trazodone (TZD) is an antidepressant drug consumed worldwide since the 1970s. By combining electropolymerization (surface imprinting) with screen-printed electrodes (SPCEs), the sensor is easy to prepare, is environmentally friendly (uses small amounts of reagents), and can be used for in situ analysis through integration with small, portable devices. The MIP was obtained using cyclic voltammetry (CV), using 4-aminobenzoic acid (4-ABA) as the functional monomer in the presence of TZF molecules in 0.1 M HCl. Non-imprinted control was also constructed in the absence of TZD. Both polymers were characterized using CV, and TZD detection was performed with DPV using the oxidation of TZD. The polymerization conditions were studied and optimized. Comparing the TZD signal for MIP/SPCE and NIP/SPCE, an imprinting factor of 71 was estimated, indicating successful imprinting of the TZD molecules within the polymeric matrix. The analytical response was linear in the range of 5–80 µM, and an LOD of 1.6 µM was estimated. Selectivity was evaluated by testing the sensor for molecules with a similar structure to TZD, and the ability of MIP/SPCE to selectively bind to TZD was proven. The sensor was applied to spiked tap water samples and human serum with good recoveries and allowed for a fast analysis (around 30 min).
- Validity and reliability of a new incremental step test for people with chronic obstructive pulmonary diseasePublication . Vilarinho, Rui; Serra, Lúcia; Águas, Ana; Alves, Carlos; Silva, Pedro Matos; Caneiras, Cátia; Mesquita Montes, AntónioIncremental step tests (IST) can be used to assess exercise capacity in people with chronic obstructive pulmonary disease (COPD). The development of a new step test based on the characteristics of the incremental shuttle walk test (ISWT) is an important study to explore. We aimed to develop a new IST based on the ISWT in people with COPD, and assess its validity (construct validity) and reliability, according to Consensus-based Standards for the selection of health status Measurement Instruments (COSMIN) recommendations. A cross-sectional study was conducted in participants recruited from hospitals/clinics. During the recruitment, the participants who presented a 6-minute walk test (6MWT) report in the previous month were also identified and the respective data was collected. Subsequently, participants attended two sessions at their homes. IST was conducted on the first visit, along with the 1 min sit-to-stand (1MSTS) test. IST was repeated on a second visit, performed 5–7 days after the first one. Spearman’s correlations were used for construct validity, by comparing the IST with the 6MWT and the 1MSTS. Intraclass correlation coefficient (ICC2,1), SE of measurement (SEM) and minimal detectable change at 95% CI (MDC95) were used for reliability. The learning effect was explored with the Wilcoxon signed-rank test. 50 participants (70.8±7.5 years) were enrolled. IST was significant and moderate correlated with the 6MWT (ρ=0.50, p=0.020), and with the 1MSTS (ρ=0.46, p=0.001). IST presented an ICC2,1=0.96, SEM=10.1 (16.6%) and MDC95=27.9 (45.8%) for the number of steps. There was a statistically significant difference between the two attempts of the IST (p=0.030). Despite the significant and moderate correlations with the 6MWT and 1MSTS, the inability to full compliance with the COSMIN recommendations does not yet allow the IST to be considered valid in people with COPD. On the other hand, the IST is a reliable test based on its high ICC, but a learning effect and an ‘indeterminate’ measurement error were shown.
- Acetil-L-Carnitina como neuroprotetor na excitotoxicidade do glutamatoPublication . Casais, Joana; Lobo, Andrea; Summavielle, TeresaA excitotoxicidade consiste na ativação excessiva de recetores de glutamato, causada pela acumulação extracelular deste neurotransmissor. A ativação dos recetores de glutamato promove o aumento excessivo da concentração intracelular de cálcio e morte neuronal associada à ativação de protéases como calpaínas e caspases - acontecimentos típicos de patologias como isquémia cerebral, Alzheimer, Parkinson e Huntington. A acetil-L-carnitina (ALC) é um éster da L-carnitina com funções neuroprotetoras, mas o mecanismo envolvido permanece desconhecido.