2D Co-MOF nanosheet-based nanozyme with ultrahigh peroxidase catalytic activity for detection of biomolecules in human serum samples.

A two-dimensional (2D) Co-MOF nanosheet-based nanozyme was developed for colorimetric detection of disease-related biomolecules. The prepared 2D Co-MOFs exhibited ultrahigh peroxidase catalytic activity. 2D Co-MOFs can catalyze the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to the blue product oxTMB, accompanying an obvious change of absorption value at 652 nm. However, alkaline phosphatase can catalyze the hydrolysis of L-ascorbic acid-2-phosphate to produce ascorbic acid which can reduce the oxTMB to TMB, resulting in an obvious color fading. Therefore, by recording the change of absorption value at 652 nm, the 2D Co-MOF nanosheets were used to detect ascorbic acid (AA) and alkaline phosphatase (ALP). The limit of detection for AA and ALP was 0.47 µM and 0.33 U L-1, respectively. The limit of quantification for AA and ALP was 1.56 µM and 1.1 U L-1, respectively. The developed nanozyme was successfully used to determine alkaline phosphatase in clinical human serum samples and the results were consistent with those provided by the hospital. Furthermore, by integrating 2D Co-MOF nanosheets with image recognition and data processing function fixed on a smartphone, a portable test of ascorbic acid was reached. Schematic presentation of the preparation of two-dimensional Co-MOF nanosheet-based nanozyme and their application in portable detection of biomolecules.

A nanoporous palladium(II) bridged coordination polymer acting as a peroxidase mimic in a method for visual detection of glucose in tear and saliva.

A nanoporous coordination polymer (NPCP) was prepared from palladium(II) chloride and 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole and is shown to act as a peroxidase mimetic. It can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 which is formed on enzymatic oxidation of glucose by glucose oxidase. Based on these findings, a sensitive glucose test was worked out at 652 nm where the intensity if the greenish-blue product is related to the actual concentration of glucose. Figures of merit include (a) rather low Km value (30 µM) which evidences the strong binding affinity of the NPCP toward glucose, (b) a high v(max) (8.5 M·s-1), (c) a 47 nM detection limit, (d) a lifetime of a month, (e) a wide working pH range (2-10), and (f) a 25-80 °C temperature range. The assay was applied to non-invasive determination of glucose assay in tear, saliva where the detection limits are found to be 61 and 91 nM, respectively. Graphical abstract DSchematic of the mechanism of the peroxidase like catalytic activity of AHMT-Pd NPCP that was applied in a selective colorimetric method for glucose detection based on TMB oxidation in the presence of enzymatically generated H2O2.

Validity and reliability of a simple 'low-tech' test for measuring choice stepping reaction time in older people.

OBJECTIVE: To establish the psychometric properties of a simple 'low-tech' choice stepping reaction time test (CSRT-M) by investigating its validity and test-retest reliability. DESIGN: Cross-sectional. SETTING: Community. SUBJECTS: A total of 169 older people from the control arm of a clinical trial and a convenience sample of 30 older people. MAIN MEASURES: Demographic, physical, cognitive and prospective falls data were collected in addition to CSRT-M. The CSRT-M time was taken as the total time to complete 20 steps onto four targets printed on a portable rubber mat. Assessment of the original electronic version (CSRT-E) and re-administration of the CSRT-M the next day was done in 30 participants. RESULTS: Multivariate regression analysis showed that the CSRT-M time was best explained by leaning balance control, quadriceps strength and cognitive functioning (R2 = 0.44). Performance on the CSRT-M was worse in older participants and participants with a presence of fall risk factors, supporting good discriminant validity. The odds of suffering multiple future falls increased by 74% (odds ratio (OR) = 1.74, 95% CI (confidence interval) = 1.14-2.65, p = 0.010) for each standard deviation increase in CSRT-M, supporting good predictive validity. Criterion validity was confirmed by a strong bivariate correlation between CSRT-M and CSRT-E (0.81, p < 0.001). Test-retest reliability for the CSRT-M was good (intraclass correlation coefficient = 0.74, 95% CI = 0.45-0.88, p < 0.001). CONCLUSIONS: A simple test of unplanned volitional stepping (CSRT-M) has excellent predictive validity for future falls, good inter-day test-retest reliability and excellent criterion validity with respect to the well-validated CSRT-E. The CSRT-M, therefore, may be a useful fall risk screening tool for older people.

A novel AIE material for sensing of Erythromycin in pure water by hydrogen bond in portable test strips and cellular imaging applications.

Erythromycin could be used to treat various bacterial infection, but it was harmful to the colonic microflora. Therefore, it is highly desirable to develop a fluorescence probe that could selectively and sensitively detect Erythromycin in pure water. In this work, a fluorescent probe named EHMC, which exhibited aggregation-induced emission (AIE) characteristic in solid state and water/EtOH binary solvent was developed for "turn on" sensing Erythromycin in pure water with high selectivity and sensitivity (detection limit: 1.78 × 10-8 M). Also, there are fewer interference from other antibiotics in the detection process of probe EHMC for Erythromycin. Moreover, probe EHMC could as a portable test strips for highly selective detection of Erythromycin and identification of different concentrations of Erythromycin. In addition, living cells imaging experiments displayed that probe EHMC could detect Erythromycin in A549 cells and BEAS-2B cells successfully. Combined with the theoretical calculation results The sensing mechanisms that the CO in Erythromycin and OH in EHMC formed intermolecular hydrogen bond and further formed new aggregates were confirmed by job' plot, 1H NMR, FT-IR, ESI-MS, DLS and TEM and DFT calculation.

Highly selective Fe3+ and F-/H2PO4- sensor based on a water-soluble cationic pillar[5]arene with aggregation-induced emission characteristic.

A water-soluble cationic pillar[5]arene (CWP5) without lager conjugated construction was first reported as a novel pillar[5]arene-based aggregation-induced emission luminogen (AIEgen), which showed a remarkable aggregation-induced emission (AIE) with the concentration increasing. The AIE effect of CWP5 has affected by different solvent, it had the lowest critical aggregation concentration (CAC) value and highest fluoresence emission intensity in DMSO solution. Simultaneously, CWP5 can serve as a chemosensor for the successively fluorescent detection of Fe3+ and F-/H2PO4- with high sensitivity and selectivity. A rewritable portable test kit made from CWP5 provides a possibility to on-site detection and manufacture of encryption and decryption materials.

Rapid visual detection of nitroaromatic explosives using a luminescent europium-organic framework material.

Rapid field screening is enormously important in forensic analysis of explosives. In this article, we used a methodology based on a strong red-fluorescent europium-organic framework (Eu-MOF) material for sensitive and selective detection of picric acid, TNT, and tetryl using the fluorescence quenching effect. Results indicate that Eu-MOF can be used for the visual detection of these three explosives with low detection limits (20-140 µg/mL) and high quenching efficiency (Ksv > 104 M-1). Furthermore, this material can be recycled just by washing it with ethanol. The fluorescence quenching mechanism is also discussed. Importantly, we prepared a portable test strip that can be used for sensing TNT, and using this, we achieved a rapid field test for explosives. Consequently, Eu-MOF is a promising candidate material for use as an explosive optical sensor.

Extreme learning machine: a new alternative for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters.

BACKGROUND: Heat collection rate and heat loss coefficient are crucial indicators for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, the direct determination requires complex detection devices and a series of standard experiments, wasting too much time and manpower. FINDINGS: To address this problem, we previously used artificial neural networks and support vector machine to develop precise knowledge-based models for predicting the heat collection rates and heat loss coefficients of water-in-glass evacuated tube solar water heaters, setting the properties measured by "portable test instruments" as the independent variables. A robust software for determination was also developed. However, in previous results, the prediction accuracy of heat loss coefficients can still be improved compared to those of heat collection rates. Also, in practical applications, even a small reduction in root mean square errors (RMSEs) can sometimes significantly improve the evaluation and business processes. CONCLUSIONS: As a further study, in this short report, we show that using a novel and fast machine learning algorithm-extreme learning machine can generate better predicted results for heat loss coefficient, which reduces the average RMSEs to 0.67 in testing.

Influence of radiation on endotoxin test using the PTS TM for 18-FDG radiopharmaceutical / Influência da radiação sobre o teste de endotoxina usando o PTS TM para 18 radiofármaco FDG

F-18 FDG (2-[18-F] fluoro-2-deoxy-D-glucose) is the most frequently used radiopharmaceutical for PET and PET CT imaging exams. The FDA recently approved the use of the PTS TM (Portable Test System) as an alternative to the standard test proposed by the United States Pharmacopeia using the LAL (Limulus Amebocyte Lysates), that takes longer to perform (about 1h) than the PTS TM (15 min). Recent studies have demonstrated that radiation could interfere with the PTS TM test. In order to study the effects of radiation on the PTS TM test and/or equipment, 27 batches of F-18 FDG produced in the Nuclear Engineering Institute were analyzed. The results showed that no direct correlation with radiation was found in any of the cases.

O FDG-18 é o radiofármaco mais utilizado nos exames de PET e PET CT. O FDA recentemente aprovou o uso do PTS TM (Portable Test System) como método alternativo ao teste padrão de endotoxina, proposto pela Farmacopéia Americana, considerando que no primeiro há um tempo de espera de 1 hora frente a somente 15 minutos do segundo. Estudo recentes demonstram que a radiação poderia interferir no teste do PTS TM. De modo a avaliar os efeitos da radiação no teste PTS TM foram analisados 27 lotes de F-18 FDG produzidos no Instituto de Engenharia Nuclear. Os resultados demonstraram que em todos os casos nenhuma correlação direta com a radiação foi observada.