scholarly journals Enhanced Performance of Reagent-Less Carbon Nanodots Based Enzyme Electrochemical Biosensors

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5576 ◽  
Author(s):  
Iria Bravo ◽  
Cristina Gutiérrez-Sánchez ◽  
Tania García-Mendiola ◽  
Mónica Revenga-Parra ◽  
Félix Pariente ◽  
...  
Keyword(s):  
Enzymatic Reaction ◽  
Lactate Concentration ◽  
Standard Addition ◽  
Carbon Nanodots ◽  
Fast Method ◽  
Lactate Oxidase ◽  
The One ◽  
Linear Concentration Range ◽  
Serum Extract

This work reports on the advantages of using carbon nanodots (CNDs) in the development of reagent-less oxidoreductase-based biosensors. Biosensor responses are based on the detection of H2O2, generated in the enzymatic reaction, at 0.4 V. A simple and fast method, consisting of direct adsorption of the bioconjugate, formed by mixing lactate oxidase, glucose oxidase, or uricase with CNDs, is employed to develop the nanostructured biosensors. Peripherical amide groups enriched CNDs are prepared from ethyleneglycol bis-(2-aminoethyl ether)-N,N,N′,N′-tetraacetic acid and tris(hydroxymethyl)aminomethane, and used as precursors. The bioconjugate formed between lactate oxidase and CNDs was chosen as a case study to determine the analytical parameters of the resulting L-lactate biosensor. A linear concentration range of 3.0 to 500 µM, a sensitivity of 4.98 × 10−3 µA·µM−1, and a detection limit of 0.9 µM were obtained for the L-lactate biosensing platform. The reproducibility of the biosensor was found to be 8.6%. The biosensor was applied to the L-lactate quantification in a commercial human serum sample. The standard addition method was employed. L-lactate concentration in the serum extract of 0.9 ± 0.3 mM (n = 3) was calculated. The result agrees well with the one obtained in 0.9 ± 0.2 mM, using a commercial spectrophotometric enzymatic kit.

scholarly journals Wearable Battery-Free Perspiration Analyzing Sites Based on Sweat Flowing on ZnO Nanoarrays

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Wanglinhan Zhang ◽  
Hongye Guan ◽  
Tianyan Zhong ◽  
Tianming Zhao ◽  
Lili Xing ◽  
...  
Keyword(s):  
Enzymatic Reaction ◽  
Lactate Concentration ◽  
Electrical Signal ◽  
Physiological Status ◽  
Zno Nanowire ◽  
Lactate Oxidase ◽  
Capillary Action ◽  
Wireless Transmitter ◽  
Flow Channels ◽  
Self Powered

AbstractWe fabricated wearable perspiration analyzing sites for actively monitoring physiological status during exercises without any batteries or other power supply. The device mainly consists of ZnO nanowire (NW) arrays and flexible polydimethylsiloxane substrate. Sweat on the skin can flow into the flow channels of the device through capillary action and flow along the channels to ZnO NWs. The sweat flowing on the NWs (with lactate oxidase modification) can output a DC electrical signal, and the outputting voltage is dependent on the lactate concentration in the sweat as the biosensing signal. ZnO NWs generate electric double layer (EDL) in sweat, which causes a potential difference between the upper and lower ends (hydrovoltaic effect). The product of the enzymatic reaction can adjust the EDL and influence the output. This device can be integrated with wireless transmitter and may have potential application in constructing sports big data. This work promotes the development of next generation of biosensors and expands the scope of self-powered physiological monitoring system.

Electrochemical assay system with single-use electrode strip for measuring lactate in whole blood

1993 ◽  
Vol 39 (11) ◽  
pp. 2312-2314 ◽  
Author(s):  
N Shimojo ◽  
K Naka ◽  
H Uenoyama ◽  
K Hamamoto ◽  
K Yoshioka ◽  
...  
Keyword(s):  
Whole Blood ◽  
Enzymatic Reaction ◽  
Lactate Concentration ◽  
Assay System ◽  
Lactate Oxidase ◽  
Electron Mediator ◽  
Electrochemical Assay ◽  
Electrode Strip ◽  
Before And After ◽  
Single Use

Abstract We have developed an assay system for measuring lactate in whole blood, consisting of a single-use strip of an enzyme-coated electrode and a small meter. The electrode strip is made of three plastic films: a cover sheet, a spacer, and an insulation layer printed with electrodes that are coated with lactate oxidase (EC 1.1.3.x) and ferricyanide as an electron mediator. The meter measures the magnitude of the anodic current of the reduced mediator by the enzymatic reaction and displays the lactate concentration 60 s after a blood sample (5 microL) is applied. The calibration curve was linear up to 20 mmol/L, and the between-run CVs at three concentrations were 1.7-8.4%. Lactate concentrations determined by this method (y) in blood samples from healthy individuals before and after exercise agreed with the results obtained by the conventional enzymatic method (x): y = 0.97x - 0.3, Sy/x = 0.7. This assay provides a rapid and convenient test for measuring blood lactate concentrations.

Inhibition of Enzymatic Reactions. A Rapid Method to Determine the Index pI50

2002 ◽  
Vol 57 (5-6) ◽  
pp. 496-499 ◽  
Author(s):  
David Kulhavý ◽  
Alexander Čegan ◽  
Karel Komers ◽  
Jaromír Mindl
Keyword(s):  
Rapid Method ◽  
Mixed Type ◽  
Enzymatic Reaction ◽  
Reaction Rates ◽  
Fast Method ◽  
Enzymatic Reactions ◽  
Initial Substrate ◽  
The One ◽  
Hydrolysis Of

The activity of every substance I inhibiting an enzymatic reaction can be approximately evaluated by the index pI50. This paper describes a simple and fast method of estimate and/or determination of this index. The method is based on the linearity of the dependence of the ratio of reaction rates of uninhibited and inhibited reaction vs. concentration of the inhibitor at constant initial substrate and enzyme concentrations for fully competitive, noncompetitive, uncompetitive and mixed type of inhibition by the one inhibitor. The validity of the method is demonstrated by four inhibitors of hydrolysis of acetylthiocholine by butyrylcholine esterase.

A CASE STUDY OF NL INFLUENCE IN UNIS FKIP ENGLISH DEPARTMENT STUDENTS' INTERLANGUAGE

2018 ◽  
Vol 18 (1) ◽  
pp. 46-54
Author(s):  
Irmala Sukendra ◽  
Agus Mulyana ◽  
Imam Sudarmaji
Keyword(s):  
Second Language ◽  
Second Language Acquisition ◽  
Native Speakers ◽  
Communicative Competence ◽  
Mother Tongue ◽  
Universal Grammar ◽  
Similar System ◽  
The One ◽  
L1 Acquisition

Regardless to the facts that English is being taught to Indonesian students starting from early age, many Indonesian thrive in learning English. They find it quite troublesome for some to acquire the language especially to the level of communicative competence. Although Krashen (1982:10) states that “language acquirers are not usually aware of the fact that they are acquiring language, but are only aware of the fact that they are using the language for communication”, second language acquisition has several obstacles for learners to face and yet the successfulness of mastering the language never surmounts to the one of the native speakers. Learners have never been able to acquire the language as any native speakers do. Mistakes are made and inter-language is unavoidable. McNeili in Ellis (1985, p. 44) mentions that “the mentalist views of L1 acquisition hypothesizes the process of acquisition consists of hypothesis-testing, by which means the grammar of the learner’s mother tongue is related to the principles of the ‘universal grammar’.” Thus this study intends to find out whether the students go through the phase of interlanguage in their attempt to acquire second language and whether their interlanguage forms similar system as postulated by linguists (Krashen).

Interrelationships between municipal spatial policy strategy and airport operation and development. Lodz Airport case study

2018 ◽  
Vol 59 (1) ◽  
pp. 65-79
Author(s):  
Katarzyna Nikorowicz-Zatorska
Keyword(s):  
Land Use ◽  
Urban Planning ◽  
Cultural Development ◽  
The Other ◽  
Local Authorities ◽  
Spatial Management ◽  
The One ◽  
Surrounding Areas

Abstract The present paper focuses on spatial management regulations in order to carry out investment in the field of airport facilities. The construction, upgrades, and maintenance of airports falls within the area of responsibility of local authorities. This task poses a great challenge in terms of organisation and finances. On the one hand, an active airport is a municipal landmark and drives local economic, social and cultural development, and on the other, the scale of investment often exceeds the capabilities of local authorities. The immediate environment of the airport determines its final use and prosperity. The objective of the paper is to review legislation that affects airports and the surrounding communities. The process of urban planning in Lodz and surrounding areas will be presented as a background to the problem of land use management in the vicinity of the airport. This paper seeks to address the following questions: if and how airports have affected urban planning in Lodz, does the land use around the airport prevent the development of Lodz Airport, and how has the situation changed over the time? It can be assumed that as a result of lack of experience, land resources and size of investments on one hand and legislative dissonance and peculiar practices on the other, aviation infrastructure in Lodz is designed to meet temporary needs and is characterised by achieving short-term goals. Cyclical problems are solved in an intermittent manner and involve all the municipal resources, so there’s little left to secure long-term investments.

De la gestión local a la gobernanza global: actores e interacciones multiniveles en la gestión del agua en la ciudad de México

2011 ◽  
Vol 1 (3) ◽  
pp. 34-66
Author(s):  
Joyce Valdovinos
Keyword(s):  
Private Sector ◽  
Water Governance ◽  
The State ◽  
Public Authorities ◽  
Service Contracts ◽  
Governance Model ◽  
Role Of The State ◽  
The One

The provision of water services has traditionally been considered a responsibility of the state. During the late 1980s, the private sector emerged as a key actor in the provision of public services. Mexico City was no exception to this trend and public authorities awarded service contracts to four private consortia in 1993. Through consideration of this case study, two main questions arise: First, why do public authorities establish partnerships with the private sector? Second, what are the implications of these partnerships for water governance? This article focuses, on the one hand, on the conceptual debate of water as a public and/or private good, while identifying new trends and strategies carried out by private operators. On the other hand, it analyzes the role of the state and its relationships with other actors through a governance model characterized by partnerships and multilevel networks.Spanish La provisión del servicio del agua ha sido tradicionalmente considerada como una responsabilidad del Estado. A finales de la década de 1980, el sector privado emerge como un actor clave en el suministro de servicios públicos. La ciudad de México no escapa a esta tendencia y en 1993 las autoridades públicas firman contratos de servicios con cuatro consorcios privados. A través de este estudio de caso, dos preguntas son planteadas: ¿Por qué las autoridades públicas establecen partenariados con el sector privado? ¿Cuáles son las implicaciones de dichos partenariados en la gobernanza del agua? Este artículo aborda por una parte, el debate conceptual del agua como bien público y/o privado, identificando nuevas tendencias y estrategias de los operadores privados. Por otra parte, se analizan el rol y las relaciones del Estado con otros actores a través de un modelo de gobernanza, definido en términos de partenariados y redes multi-niveles.French Les services de l'eau ont été traditionnellement considérés comme une responsabilité de l'État. À la fin des années 1980, le secteur privé est apparu comme un acteur clé dans la fourniture de certains services publics. La ville de Mexico n'a pas échappé à cette tendance et en 1993, les autorités publiques ont signé des contrats de services avec quatre consortiums privés. À travers cette étude de cas, nous nous interrogerons sur deux aspects : pourquoi les autorités publiques établissentelles des partenariats avec le secteur privé ? Quelles sont les implications de ces partenariats sur la gouvernance de l'eau ? Cet article s'intéresse, d'une part, au débat conceptuel sur l'eau en tant que bien public et/ou privé, en identifiant les tendances nouvelles et les stratégies menées par les opérateurs privés. D'autre part y sont analysés le rôle de l'État et ses relations avec d'autres acteurs à travers un modèle de gouvernance, défini en termes de partenariats, et des réseaux multi-niveaux.

Paranasal Sinus Mucocele Clinical, imagistic and biochemical aspects

2018 ◽  
Vol 69 (8) ◽  
Author(s):  
Doina Vesa ◽  
Cristian Martu ◽  
Razvan Leata ◽  
Ludmila Lozneanu ◽  
luminita Radulescu ◽  
...  
Keyword(s):  
Facial Asymmetry ◽  
Retrospective Case ◽  
Mri Scans ◽  
The One ◽  
Ethmoid Sinuses ◽  
Retrospective Case Study ◽  
Cellular Components ◽  
Ct And Mri

Paranasal mucoceles are a type of cysts that evolve slowly and are asymptomatic; this poses a difficulty in diagnosing the patient because the symptoms can go unnoticed. The mucocele evolves unpredictably. On the one hand, it can become infected turning into pyoceles and on the other hand, it can invade important regions such as the orbital, cranial or genian regions, creating facial asymmetry. This is a retrospective case study of 37 patients diagnosed with sinus mucoceles, followed up by clinical examination and paraclinical tests such as CT and MRI scans. The biochemical components of the liquid from within the mucocele were analyzed and the following criteria were recorded: NaCl-, Cl-, Na+ and cholesterine as well as cellular components such as mastocytes, macrophages, hematocytes and leucocytes. In all cases, the treatment option was surgery with favorable post-operative and follow-up evaluation. The mucoceles that appeared post-operatively (maxillary and ethmoid sinuses) evolved more rapidly than the mucoceles that were induced byan external injury. Longer follow-up of operated patients permitted a more timely diagnosis of recurrences.

Freedom of speech is not freedom from ethics: the 2019 Israel Folau media controversy as a case study

2021 ◽  
pp. 1329878X2199289
Author(s):  
Jay Daniel Thompson ◽  
Denis Muller
Keyword(s):  
Content Analysis ◽  
Freedom Of Speech ◽  
Rugby Player ◽  
Ethical Principles ◽  
Framing Analysis ◽  
The Media ◽  
The One

This article examines how freedom of speech is framed in the media controversy surrounding the Australian rugby player Israel Folau’s April 2019 Instagram post. A content analysis and framing analysis of newspaper reportage reveals that the controversy has been largely discussed in terms of whether or not Folau’s speech was being curtailed and whether this curtailing indicates a broader, ideologically motivated censoriousness. This discussion is problematic in that it says little about the actual substance of Folau’s post. This article argues that debates surrounding freedom of speech such as the one involving Folau could and should be enriched by an engagement with ethical principles. This engagement is premised on a commitment to the free exchange of views, while acknowledging that ‘speech’ is not always inherently beneficial for democracy, nor worth defending.

scholarly journals Scenario Analyses of Exhaust Emissions Reduction through the Introduction of Electric Vehicles into the City

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 2030
Author(s):  
Marianna Jacyna ◽  
Renata Żochowska ◽  
Aleksander Sobota ◽  
Mariusz Wasiak
Keyword(s):  
Inner City ◽  
Electric Vehicles ◽  
Transport Model ◽  
Exhaust Emissions ◽  
Scenario Analyses ◽  
High Emission ◽  
Clean Air ◽  
The One ◽  
The City

In recent years, policymakers of urban agglomerations in various regions of the world have been striving to reduce environmental pollution from harmful exhaust and noise emissions. Restrictions on conventional vehicles entering the inner city are being introduced and the introduction of low-emission measures, including electric ones, is being promoted. This paper presents a method for scenario analysis applied to study the reduction of exhaust emissions by introducing electric vehicles in a selected city. The original scenario analyses relating to real problems faced by contemporary metropolitan areas are based on the VISUM tool (PTV Headquarters for Europe: PTV Planung Transport Verkehr AG, 76131 Karlsruhe, Germany). For the case study, the transport model of the city of Bielsko-Biala (Poland) was used to conduct experiments with different forms of participation of electric vehicles on the one hand and traffic restrictions for high emission vehicles on the other hand. Scenario analyses were conducted for various constraint options including inbound, outbound, and through traffic. Travel time for specific transport relations and the volume of harmful emissions were used as criteria for evaluating scenarios of limited accessibility to city zones for selected types of vehicles. The comparative analyses carried out showed that the introduction of electric vehicles in the inner city resulted in a significant reduction in the emission of harmful exhaust compounds and, consequently, in an increase in the area of clean air in the city. The case study and its results provide some valuable insights and may guide decision-makers in their actions to introduce both driving ban restrictions for high-emission vehicles and incentives for the use of electric vehicles for city residents.

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