scholarly journals Pesticide Residues Identification by Optical Spectrum in the Time-Sequence of Enzyme Inhibitors Performed on Microfluidic Paper-Based Analytical Devices (µPADs)

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2428 ◽  
Author(s):  
Ning Yang ◽  
Naila Shaheen ◽  
Liangliang Xie ◽  
Junjie Yu ◽  
Hussain Ahmad ◽  
...  

Pesticides vary in the level of poisonousness, while a conventional rapid test card only provides a general “absence or not” solution, which cannot identify the various genera of pesticides. In order to solve this problem, we proposed a seven-layer paper-based microfluidic chip, integrating the enzyme acetylcholinesterase (AChE) and chromogenic reaction. It enables on-chip pesticide identification via a reflected light intensity spectrum in time-sequence according to the different reaction efficiencies of pesticide molecules and assures the optimum temperature for enzyme activity. After pretreatment of figures of reflected light intensity during the 15 min period, the figures mainly focused on the reflected light variations aroused by the enzyme inhibition assay, and thus, the linear discriminant analysis showed satisfying discrimination of imidacloprid (Y = −1.6525X − 139.7500), phorate (Y = −3.9689X − 483.0526), and avermectin (Y = −2.3617X − 28.3082). The correlation coefficients for these linearity curves were 0.9635, 0.8093, and 0.9094, respectively, with a 95% limit of agreement. Then, the avermectin class chemicals and real-world samples (i.e., lettuce and rice) were tested, which all showed feasible graphic results to distinguish all the chemicals. Therefore, it is feasible to distinguish the three tested kinds of pesticides by the changes in the reflected light spectrum in each min (15 min) via the proposed chip with a high level of automation and integration.

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1113
Author(s):  
Mohammed Asadullah Khan ◽  
Jürgen Kosel

An integrated polymer-based magnetohydrodynamic (MHD) pump that can actuate saline fluids in closed-channel devices is presented. MHD pumps are attractive for lab-on-chip applications, due to their ability to provide high propulsive force without any moving parts. Unlike other MHD devices, a high level of integration is demonstrated by incorporating both laser-induced graphene (LIG) electrodes as well as a NdFeB magnetic-flux source in the NdFeB-polydimethylsiloxane permanent magnetic composite substrate. The effects of transferring the LIG film from polyimide to the magnetic composite substrate were studied. Operation of the integrated magneto hydrodynamic pump without disruptive bubbles was achieved. In the studied case, the pump produces a flow rate of 28.1 µL/min. while consuming ~1 mW power.


Author(s):  
Igor Junio de Oliveira Custódio ◽  
Gibson Moreira Praça ◽  
Leandro Vinhas de Paula ◽  
Sarah da Glória Teles Bredt ◽  
Fabio Yuzo Nakamura ◽  
...  

This study aimed to analyze the intersession reliability of global positioning system (GPS-based) distances and accelerometer-based (acceleration) variables in small-sided soccer games (SSG) with and without the offside rule, as well as compare variables between the tasks. Twenty-four high-level U-17 soccer athletes played 3 versus 3 (plus goalkeepers) SSG in two formats (with and without the offside rule). SSG were performed on eight consecutive weeks (4 weeks for each group), twice a week. The physical demands were recorded using a GPS with an embedded triaxial accelerometer. GPS-based variables (total distance, average speed, and distances covered at different speeds) and accelerometer-based variables (Player Load™, root mean square of the acceleration recorded in each movement axis, and the root mean square of resultant acceleration) were calculated. Results showed that the inclusion of the offside rule reduced the total distance covered (large effect) and the distances covered at moderate speed zones (7–12.9 km/h – moderate effect; 13–17.9 km/h – large effect). In both SSG formats, GPS-based variables presented good to excellent reliability (intraclass correlation coefficients – ICC > 0.62) and accelerometer-based variables presented excellent reliability (ICC values > 0.89). Based on the results of this study, the offside rule decreases the physical demand of 3 versus 3 SSG and the physical demands required in these SSG present high intersession reliability.


Author(s):  
Blanca Alicia Correa ◽  
Juan Fernando Eusse ◽  
Danny Munera ◽  
Jose Edinson Aedo ◽  
Juan Fernando Velez

2007 ◽  
Vol 46 (No. 36) ◽  
pp. L868-L870 ◽  
Author(s):  
Masashi Kuwahara ◽  
Rie Endo ◽  
Toshio Fukaya ◽  
Takayuki Shima ◽  
Yasuhiko Iwanabe ◽  
...  

2020 ◽  
Vol 45 (9) ◽  
pp. 42-61
Author(s):  
Busra Kartal ◽  

Teachers with a high level of self-efficacy and positive attitudes are more likely to use new and constructivist approaches and to create a learning environment in which students may develop 21st-century skills. Examining pre-service teachers’ attitudes and beliefs related to teaching allow teacher preparation programs to evaluate their effectiveness on beliefs and attitudes. This correlational research investigated pre-service elementary science and mathematics teachers’ beliefs and attitudes due to gender, grade level, and department, and revealed the reliable correlation between beliefs and attitudes performing partial correlation. Results show that females feel more efficacious in teaching and have more positive attitudes than males. 4th grades also perceive a higher level of efficacy for student engagement and using instructional strategies than 1st grades. Partial correlation coefficients revealed positive strong relationships between attitudes and efficacy beliefs. Recommendations are suggested based on implications.


2021 ◽  
pp. 205-225
Author(s):  
Arkady Lyubarev

Correlation coefficients between the results of political parties in the 2016 State Duma elections in the Russian Federation as a whole and in 26 regions, as well as in the elections of regional parliaments of 35 subjects of the Russian Federation in 2012–2015 were calculated. For the 2016 State Duma elections, data was used at all levels – regions, single-member electoral districts, TEC and PEC. It is noted that the “United Russia” correlations with all major parties are generally negative. A fairly high level of correlation is observed between the liberal parties. The main focus is on correlations between parliamentary opposition parties and parties with similar names. The correlation coefficients between the results of parties and candidates in the State Duma elections of 2011 and 2016 and the Presidential elections of 2012 and 2018 were also calculated, showing the stability of the geographical distribution of the electorate of the main parties. Regional differences in the nature of correlations between the main political parties are noted. It is assumed that correlations between parties reflect not so much their ideological closeness as the social closeness of their electorate. In this regard, it is noted that a positive correlation between the results of ideologically distant parties (“Yabloko” and the Communist party or “Yabloko” and “Rodina”) is associated with their reliance on the urban electorate and, perhaps, its most educated part. The reasons for voting for spoiler parties and the role of these parties in reducing the results of the main participants in the elections are discussed.


Author(s):  
Oskar Ekelund ◽  
Kim Ekblom ◽  
Sofia Somajo ◽  
Johanna Pattison-Granberg ◽  
Karl Olsson ◽  
...  

Background: The recently launched high-throughput assays for the detection of antibodies against SARS-CoV-2 may change the managing strategies for the COVID-19 pandemic. This study aimed at investigating the performance of three high-throughput assays and one rapid lateral flow test relative to the recommended criteria defined by regulatory authorities. Methods: A total of 133 samples, including 100 pre-pandemic samples, 20 samples from SARS-CoV-2 RT-PCR positive individuals, and 13 potentially cross-reactive samples were analysed with SARS-CoV-2 IgG (Abbott), Elecsys Anti-SARS-CoV-2 (Roche), LIAISON SARS-CoV-2 S1/S2 IgG (DiaSorin) and 2019-nCOV IgG/IgM Rapid Test (Dynamiker Biotechnology Co). Results: All assays performed with a high level of specificity; however, only Abbott reached 100% (95% CI 96.3-100). The pre-pandemic samples analysed with Roche, DiaSorin and Dynamiker Biotechnology resulted in two to three false-positive results per method (specificity 96.9-98.0%). Sensitivity differed more between the assays, Roche exhibiting the highest sensitivity (100%, CI 83.9-100). The corresponding figures for Abbott, DiaSorin and Dynamiker Biotechnology were 85.0%, 77.8% and 75.0%, respectively. Conclusions: The results of the evaluated SARS-CoV-2 assays vary considerably as well as their ability to fulfil the performance criteria proposed by regulatory authorities. Introduction into clinical use in low-prevalent settings, should therefore, be made with caution.


Author(s):  
Muhammad Afif Hendrawan ◽  
Pramana Yoga Saputra ◽  
Cahya Rahmad

Nowadays, biometric modalities have gained popularity in security systems. Nevertheless, the conventional commercial-grade biometric system addresses some issues. The biggest problem is that they can be imposed by artificial biometrics. The electroencephalogram (EEG) is a possible solution. It is nearly impossible to replicate because it is dependent on human mental activity. Several studies have already demonstrated a high level of accuracy. However, it requires a large number of sensors and time to collect the signal. This study proposed a biometric system using single-channel EEG recorded during resting eyes open (EO) conditions. A total of 45 EEG signals from 9 subjects were collected. The EEG signal was segmented into 5 second lengths. The alpha band was used in this study. Discrete wavelet transform (DWT) with Daubechies type 4 (db4) was employed to extract the alpha band. Power spectral density (PSD) was extracted from each segment as the main feature. Linear discriminant analysis (LDA) and support vector machine (SVM) were used to classify the EEG signal. The proposed method achieved 86% accuracy using LDA only from the third segment. Therefore, this study showed that it is possible to utilize single-channel EEG during a resting EO state in a biometric system.


2019 ◽  
Vol 31 ◽  
pp. 1-14
Author(s):  
Silviu Bercea ◽  
Ruxandra Năstase-Bucur ◽  
Oana Teodora Moldovan ◽  
Marius Kenesz ◽  
Silviu Constantin

The human impact upon the subterranean microbiomes is not only a peril to the cave environment but might also affect future visitors. We focused on the changes that humans induced on the surfaces they came in direct or indirect contact with inside two intensely visited Romanian show caves, by means of commercially available microbial rapid test kits and molecular identification. Overall culturable bacteria abundance in the caves maintained high levels year-round while Enterobacteriaceae, coliform bacteria and Escherichiacoli levels peaked during the touristic season, reaching levels that could pose a threat to the health of the visitors. Culturable fungi abundance usually peaked in the spring, remained at a high level in the summer and started to slowly decrease towards the winter months. Differences were observed between the direct and indirect exposed surfaces, as the later had lower overall levels of bacteria and fungi, with increased Enterobacteriaceae loads. Most of the taxa identified are known biodeteriorants of subterranean surfaces and were previously associated with human altered caves. A Dothideomycete sp. previously unknown to the cave environments was detected. This was the first study to analyse the dynamics of the microbial communities of delicate subterranean surfaces in show caves through the use of commercially available test kits. We revealed that exposed surfaces in show caves, in direct or indirect contact with tourists, are host to high concentrations of cultivable microbes. The touristic activity was shown to influence the abundance and dynamics of the microbial communities inhabiting surfaces of show caves.


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