scholarly journals Light-Addressable Actuator-Sensor Platform for Monitoring and Manipulation of pH Gradients in Microfluidics: A Case Study with the Enzyme Penicillinase

Biosensors ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 171
Author(s):  
Rene Welden ◽  
Melanie Jablonski ◽  
Christina Wege ◽  
Michael Keusgen ◽  
Patrick Hermann Wagner ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Enzymatic Reaction ◽  
Microfluidic Channel ◽  
Ph Gradients ◽  
Ph Influence ◽  
Sensor Platform ◽  
Local Ph ◽  
Scanning Electron ◽  
Light Addressable Potentiometric Sensor

The feasibility of light-addressed detection and manipulation of pH gradients inside an electrochemical microfluidic cell was studied. Local pH changes, induced by a light-addressable electrode (LAE), were detected using a light-addressable potentiometric sensor (LAPS) with different measurement modes representing an actuator-sensor system. Biosensor functionality was examined depending on locally induced pH gradients with the help of the model enzyme penicillinase, which had been immobilized in the microfluidic channel. The surface morphology of the LAE and enzyme-functionalized LAPS was studied by scanning electron microscopy. Furthermore, the penicillin sensitivity of the LAPS inside the microfluidic channel was determined with regard to the analyte’s pH influence on the enzymatic reaction rate. In a final experiment, the LAE-controlled pH inhibition of the enzyme activity was monitored by the LAPS.

scholarly journals Deep Learning Based Instance Segmentation of Titanium Dioxide Particles in the Form of Agglomerates in Scanning Electron Microscopy

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 968
Author(s):  
Paul Monchot ◽  
Loïc Coquelin ◽  
Khaled Guerroudj ◽  
Nicolas Feltin ◽  
Alexandra Delvallée ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Titanium Dioxide ◽  
Learning Community ◽  
Spherical Particles ◽  
Average Value ◽  
Size Characterization ◽  
Scanning Electron

The size characterization of particles present in the form of agglomerates in images measured by scanning electron microscopy (SEM) requires a powerful image segmentation tool in order to properly define the boundaries of each particle. In this work, we propose to use an algorithm from the deep statistical learning community, the Mask-RCNN, coupled with transfer learning to overcome the problem of generalization of the commonly used image processing methods such as watershed or active contour. Indeed, the adjustment of the parameters of these algorithms is almost systematically necessary and slows down the automation of the processing chain. The Mask-RCNN is adapted here to the case study and we present results obtained on titanium dioxide samples (non-spherical particles) with a level of performance evaluated by different metrics such as the DICE coefficient, which reaches an average value of 0.95 on the test images.

Reversible Light‐Responsive Coacervate Microdroplets with Rapid Regulation of Enzymatic Reaction Rate

2021 ◽  
Author(s):  
Yan Huang ◽  
Xiaoliang Wang ◽  
Junbo Li ◽  
Youping Lin ◽  
Haixu Chen ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Enzymatic Reaction

A Context-Aware Information Model for Elderly Homecare Services in a Smart Home

2009 ◽  
Author(s):  
Feng Zhou ◽  
Jianxin Roger Jiao ◽  
Songlin Chen ◽  
Daqing Zhang
Keyword(s):  
Home Environment ◽  
Smart Home ◽  
Rough Set Theory ◽  
Research Problem ◽  
Information Model ◽  
Context Aware ◽  
Sensor Platform ◽  
Smart Home Environment ◽  
Manual Assistance

One of the critical situations facing the society across the globe is the problem of elderly homecare services (EHS) due to the aggravation of the society coupled with diseases and limited social resources. This problem has been typically dealt with by manual assistance from caregivers and/or family members. The emerging Ambience Intelligence (AmI) technology suggests itself to be of great potential for EHS applications, owing to its strength in constructing a pervasive computing environment that is sensitive and responsive to the presence of human users. The key challenge of AmI implementation lies in context awareness, namely how to align with the specific decision making scenarios of particular EHS applications. This paper proposes a context-aware information model in a smart home to tackle the EHS problem. Mainly, rough set theory is applied to construct user activity models for recognizing various activities of daily living (ADLs) based on the sensor platform constructed in a smart home environment. Subsequently, issues of case comprehension and homecare services are also discussed. A case study in the smart home environment is presented. Initial findings from the case study suggest the importance of the research problem, as well as the feasibility and potential of the proposed framework.

scholarly journals A MATLAB Toolbox for Modeling Genetic Circuits in Cell-Free Systems

2020 ◽  
Author(s):  
Vipul Singhal ◽  
Zoltan A. Tuza ◽  
Zachary Z. Sun ◽  
Richard M. Murray
Keyword(s):  
Reaction Rate ◽  
Behavior Prediction ◽  
Genetic Circuits ◽  
Matlab Toolbox ◽  
Parameter Inference ◽  
Batch Mode ◽  
E Coli ◽  
Entire Duration ◽  
Resource Loading

AbstractWe introduce a MATLAB based simulation toolbox, called txtlsim, for an E. coli based Transcription-Translation (TX-TL) system. This toolbox accounts for several cell-free related phenomena, such as resource loading, consumption, and degradation, and in doing so, models the dynamics of TX-TL reactions for the entire duration of batch-mode experiments. We use a Bayesian parameter inference approach to characterize the reaction rate parameters associated with the core transcription, translation and mRNA degradation mechanics of the toolbox, allowing it to reproduce constitutive mRNA and protien expression trajectories. We demonstrate the use of this characterized toolbox in a circuit behavior prediction case study for an incoherent feed-forward loop.

Enzymatic Reaction Kinetics of Papain-Extracted Collagen from Bighead Carp Scales

2015 ◽  
Vol 727-728 ◽  
pp. 56-60
Author(s):  
Min Li ◽  
Liu Meng Chen ◽  
Bo Quan Jiang
Keyword(s):  
Reaction Kinetics ◽  
Reaction Rate ◽  
Enzymatic Reaction ◽  
Raw Material ◽  
Bighead Carp ◽  
Fish Waste ◽  
Biomedical Material ◽  
Production Output ◽  
And Control ◽  
Kinetics Of

Collagen, as an important biomedical material, has been widely used in medical industry. Fish waste (scales, skins, bones, fins and swim bladders) is a kind of newly developed alternative collagen raw material.This paper uesd papain as enzyme and local bighead fish scales as raw material to extract collagen. More attention was paid to the study on enzymatic reaction kinetics of papain-extracted collagen. The results showed that two kinds of kinetic models(Michaelis-Menten equations and exponential type dynamic equations) at 20, 25 and 28°C were established, respectively and experimentally proved to be basically in agreement with the actual values. These models have a great significance to predict, adjust and control the reaction rate and production output under different conditions.

Optimized Determination of γ-Glutamyltransferase by Reaction-Rate Analysis

1974 ◽  
Vol 20 (9) ◽  
pp. 1121-1124 ◽  
Author(s):  
Sidney B Rosalki ◽  
David Tarlow
Keyword(s):  
Dilute Hydrochloric Acid ◽  
Reaction Rate ◽  
Enzymatic Reaction ◽  
Enzyme Reaction ◽  
Enzyme Reactions ◽  
Rate Analysis ◽  
Acid Substrate ◽  
Incubation Buffer ◽  
Optimal Ph

Abstract We describe a method for measuring γ-glutamyltransferase (EC 2.3.2.2) activity in serum, which can be used with automated enzyme analyzers (such as the LKB 8600 Reaction Rate Analyzer) that require enzyme reactions to be initiated with substrate. The method also permits optimal determination conditions to be obtained at 37 °C. The enzymatic reaction is commenced by adding γ-glutamyl-p-nitroanilide dissolved in dilute hydrochloric acid to samples pre-incubated with tris(hydroxymethyl)aminomethane—glycylglycine buffer. The p-nitroaniline liberated is continously monitored at 37 °C at 405 nm. The pH of the pre-incubation buffer is such that the optimal pH for the enzyme reaction results from addition of the acid substrate solution.

scholarly journals A Multi-Scale Approach to Modeling the Interfacial Reaction Kinetics of Lipases with Emphasis on Enzyme Adsorption at Water-Oil Interfaces

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1082
Author(s):  
Sherly Rusli ◽  
Janna Grabowski ◽  
Anja Drews ◽  
Matthias Kraume
Keyword(s):  
Reaction Kinetics ◽  
Surface Area ◽  
Reaction Rate ◽  
Enzymatic Reaction ◽  
Interfacial Area ◽  
Enzyme Adsorption ◽  
Multi Scale ◽  
Specific Interfacial Area ◽  
Enzyme Molecules ◽  
Interfacial Adsorption

The enzymatic hydrolysis of triglycerides with lipases (EC 3.1.1.3.) involves substrates from both water and oil phases, with the enzyme molecules adsorbed at the water-oil (w/o) interface. The reaction rate depends on lipase concentration at the interface and the available interfacial area in the emulsion. In emulsions with large drops, the reaction rate is limited by the surface area. This effect must be taken into account while modelling the reaction. However, determination of the interfacial saturation is not a trivial matter, as enzyme molecules have the tendency to unfold on the interface, and form multi-layer, rendering many enzyme molecules unavailable for the reaction. A multi-scale approach is needed to determine the saturation concentration with specific interfacial area so that it can be extrapolated to droplet swarms. This work explicitly highlights the correlation between interfacial adsorption and reaction kinetics, by integration of the adsorption kinetics into the enzymatic reaction. The rate constants were fitted globally against data from both single droplet and drop swarm experiments. The amount of adsorbed enzymes on the interface was measured in a single drop with a certain surface area, and the enzyme interfacial loading was estimated by Langmuir adsorption isotherm.

Automated Enzymatic Determination of L-Lactate in Serum, with Use of a Miniature Centrifugal Anlyzer

1976 ◽  
Vol 22 (12) ◽  
pp. 2038-2041 ◽  
Author(s):  
T P Hadjiioannou ◽  
S I Hadjiioannou ◽  
S D Brunk ◽  
H V Malmstadt
Keyword(s):  
Lactate Dehydrogenase ◽  
Reaction Rate ◽  
Enzymatic Reaction ◽  
Reaction Rates ◽  
Enzymatic Determination ◽  
Analytical Recovery ◽  
Rate Method ◽  
Relative Errors ◽  
Lithium Lactate

Abstract We describe an automated enzymatic reaction-rate method for spectrophotometric determination of lactate in serum with a miniature centrifugal analyzer. The L(+)-lactate is selectively oxidized in the presence of lactate dehydrogenase (EC 1.1.1.27) and NAD+ to from NADH, whitch is measured from its absorption. Reaction rates are determined automatically, and unknown concentrations are calculated from a computer0generated calibration curve with aqueous lithium lactate standards. Lactte concentrations in the range 0.32-1.6 µg/4 µl (80-400 mg/liter) of sample were determined with relative errors and coefficient of variation of 4.8%. Analytical recovery of lactate added to pooled serum was 89-112% (average, 101%). Comparison with a kit ("Rapid Lactate") method gave a correlation coefficient squared of 0.979 over a concentration range of 39-779 mg/liter.

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