scholarly journals In Situ Oxidation of Cu2O Crystal for Electrochemical Detection of Glucose

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2926 ◽  
Author(s):  
Chenlin Lu ◽  
Zhipeng Li ◽  
Liwei Ren ◽  
Nan Su ◽  
Diannan Lu ◽  
...  
Keyword(s):  
Electrochemical Detection ◽  
Electrode Surface ◽  
Glucose Sensor ◽  
High Specificity ◽  
Response Range ◽  
Peak Sensitivity ◽  
Cu2o Nanoparticles ◽  
High Concentrations ◽  
Glucose Electrode

The development of a sensitive, quick-responding, and robust glucose sensor is consistently pursued for use in numerous applications. Here, we propose a new method for preparing a Cu2O electrode for the electrochemical detection of glucose concentration. The Cu2O glucose electrode was prepared by in situ electrical oxidation in an alkaline solution, in which Cu2O nanoparticles were deposited on the electrode surface to form a thin film, followed by the growth of Cu(OH)2 nanorods or nanotubes. The morphology and electrocatalytic activity of a Cu2O glucose electrode can be tuned by the current density, reaction time, and NaOH concentration. The results from XRD, SEM, and a Raman spectrum show that the electrode surface was coated with cubic Cu2O nanoparticles with diameters ranging from 50 to 150 nm. The electrode exhibited a detection limit of 0.0275 mM, a peak sensitivity of 2524.9 μA·cm−2·mM−1, and a linear response range from 0.1 to 1 mM. The presence of high concentrations of ascorbic acid, uric acid, dopamine and lactose appeared to have no effects on the detection of glucose, indicating a high specificity and robustness of this electrode.

New Technologies for Decontamination of Radioactive Substances Scattered by Nuclear Accident / Nowe Technologie Dekontaminacji Radioaktywnych Substancji Rozproszonych Przez Awarie Nuklearna

2013 ◽  
Vol 58 (1) ◽  
pp. 283-290 ◽  
Author(s):  
Y. Nishizaki ◽  
H. Miyamae ◽  
S. Ichikawa ◽  
K. Izumiya ◽  
T. Takano ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
New Technologies ◽  
Ferric Hydroxide ◽  
Nuclear Accident ◽  
Radioactive Cesium ◽  
Cesium Ions ◽  
Naoh Solution ◽  
High Concentrations ◽  
Water Rinsing

Our effort for decontamination of radioactive cesium scattered widely by nuclear accident in March 2011 in Fukushima, Japan has been described. Radioactive cesium scattered widely in Japan has been accumulating in arc or plasma molten-solidified ash in waste incinerating facilities up to 90,000 Bq/kg of the radioactive waste. Water rinsing of the ash resulted in dissolution of cesium ions together with high concentrations of potassium and sodium ions. Although potassium inhibits the adsorption of cesium on zeolite, we succeeded to precipitate cesium by in-situ formation of ferric ferrocyanide and iron rust in the radioactive filtrate after rinsing of the radioactive ash with water. Because the regulation of no preservation of any kind of cyanide substances, cesium was separated from the precipitate consisting of cesium-captured ferric ferrocyanide and ferric hydroxide in diluted NaOH solution and subsequent filtration gave rise to the potassium-free radioactive filtrate. Cesium was captured by zeolite from the potassium-free radioactive filtrate. The amount of this final radioactive waste of zeolite was significantly lower than that of the arc-molten-solidified ash.

scholarly journals An Autonomous Platform for Near Real-Time Surveillance of Harmful Algae and Their Toxins in Dynamic Coastal Shelf Environments

2021 ◽  
Vol 9 (3) ◽  
pp. 336
Author(s):  
Stephanie K. Moore ◽  
John B. Mickett ◽  
Gregory J. Doucette ◽  
Nicolaus G. Adams ◽  
Christina M. Mikulski ◽  
...  
Keyword(s):  
Real Time ◽  
Domoic Acid ◽  
Harmful Algae ◽  
Coastal Trapped Waves ◽  
Resource Managers ◽  
Bloom Formation ◽  
High Concentrations ◽  
Data Gap ◽  
Autonomous Technology

Efforts to identify in situ the mechanisms underpinning the response of harmful algae to climate change demand frequent observations in dynamic and often difficult to access marine and freshwater environments. Increasingly, resource managers and researchers are looking to fill this data gap using unmanned systems. In this study we integrated the Environmental Sample Processor (ESP) into an autonomous platform to provide near real-time surveillance of harmful algae and the toxin domoic acid on the Washington State continental shelf over a three-year period (2016–2018). The ESP mooring design accommodated the necessary subsystems to sustain ESP operations, supporting deployment durations of up to 7.5 weeks. The combination of ESP observations and a suite of contextual measurements from the ESP mooring and a nearby surface buoy permitted an investigation into toxic Pseudo-nitzschia spp. bloom dynamics. Preliminary findings suggest a connection between bloom formation and nutrient availability that is modulated by wind-forced coastal-trapped waves. In addition, high concentrations of Pseudo-nitzschia spp. and elevated levels of domoic acid observed at the ESP mooring location were not necessarily associated with the advection of water from known bloom initiation sites. Such insights, made possible by this autonomous technology, enable the formulation of testable hypotheses on climate-driven changes in HAB dynamics that can be investigated during future deployments.

scholarly journals Fe3O4@C Nanoparticles Synthesized by In Situ Solid-Phase Method for Removal of Methylene Blue

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 330
Author(s):  
Hengli Xiang ◽  
Genkuan Ren ◽  
Yanjun Zhong ◽  
Dehua Xu ◽  
Zhiye Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Solid Phase ◽  
Raw Materials ◽  
Phase Method ◽  
Maximum Adsorption Capacity ◽  
High Catalytic Activity ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
High Concentrations

Fe3O4@C nanoparticles were prepared by an in situ, solid-phase reaction, without any precursor, using FeSO4, FeS2, and PVP K30 as raw materials. The nanoparticles were utilized to decolorize high concentrations methylene blue (MB). The results indicated that the maximum adsorption capacity of the Fe3O4@C nanoparticles was 18.52 mg/g, and that the adsorption process was exothermic. Additionally, by employing H2O2 as the initiator of a Fenton-like reaction, the removal efficiency of 100 mg/L MB reached ~99% with Fe3O4@C nanoparticles, while that of MB was only ~34% using pure Fe3O4 nanoparticles. The mechanism of H2O2 activated on the Fe3O4@C nanoparticles and the possible degradation pathways of MB are discussed. The Fe3O4@C nanoparticles retained high catalytic activity after five usage cycles. This work describes a facile method for producing Fe3O4@C nanoparticles with excellent catalytic reactivity, and therefore, represents a promising approach for the industrial production of Fe3O4@C nanoparticles for the treatment of high concentrations of dyes in wastewater.

scholarly journals Electrochemical detection of free-chlorine in Water samples facilitated by in-situ pH control using interdigitated microelectrodes

2020 ◽  
Vol 325 ◽  
pp. 128774 ◽  
Author(s):  
Ian Seymour ◽  
Benjamin O’Sullivan ◽  
Pierre Lovera ◽  
James F. Rohan ◽  
Alan O’Riordan
Keyword(s):  
Electrochemical Detection ◽  
Water Samples ◽  
Ph Control ◽  
Free Chlorine ◽  
Interdigitated Microelectrodes

Effects of hydrogen peroxide and hypochlorite on membrane potential of mitochondria in situ in rat heart cells

1991 ◽  
Vol 69 (11) ◽  
pp. 1705-1712 ◽  
Author(s):  
Noburu Konno ◽  
K. J. Kako
Keyword(s):  
Hydrogen Peroxide ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Rat Heart ◽  
Mitochondrial Membrane ◽  
Isolated Rat Heart ◽  
Heart Mitochondria ◽  
High Concentrations ◽  
Isolated Rat

Hydrogen peroxide (H2O2) and hypochlorite (HOCl) cause a variety of cellular dysfunctions. In this study we examined the effects of these agents on the electrical potential gradient across the inner membrane of mitochondria in situ in isolated rat heart myocytes. Myocytes were prepared by collagenase digestion and incubated in the presence of H2O2 or HOCl. Transmembrane electrical gradients were measured by distribution of [3H]triphenylmethylphosphonium+, a lipophilic cation. The particulate fraction was separated from the cytosolic compartment first by permeabilization using digitonin, followed by rapid centrifugal sedimentation through a bromododecane layer. We found that the mitochondrial membrane potential (161 ± 7 mV, negative inside) was relatively well maintained under oxidant stress, i.e., the potential was decreased only at high concentrations of HOCl and H2O2 and gradually with time. The membrane potential of isolated rat heart mitochondria was affected similarly by H2O2 and HOCl in a concentration- and time-dependent manner. High concentrations of oxidants also reduced the cellular ATP level but did not significantly change the matrix volume. When the extra-mitochondrial free calcium concentration was increased in permeabilized myocytes, the transmembrane potential was decreased proportionally, and this decrease was potentiated further by H2O2. These results support the view that heart mitochondria are equipped with well-developed defense mechanisms against oxidants, but the action of H2O2 on the transmembrane electrical gradient is exacerbated by an increase in cytosolic calcium. Keywords: ATP, calcium, cardiomyocyte, cell defense, mitochondrial membrane potential, oxidant, triphenylmethylphosphonium.

scholarly journals Competition between Metals for Binding to Methanobactin Enables Expression of Soluble Methane Monooxygenase in the Presence of Copper

2014 ◽  
Vol 81 (3) ◽  
pp. 1024-1031 ◽  
Author(s):  
Bhagyalakshmi Kalidass ◽  
Muhammad Farhan Ul-Haque ◽  
Bipin S. Baral ◽  
Alan A. DiSpirito ◽  
Jeremy D. Semrau
Keyword(s):  
Methane Monooxygenase ◽  
High Specificity ◽  
Copper Uptake ◽  
Content Type ◽  
Soluble Methane Monooxygenase ◽  
Sds Page ◽  
Genes Encoding ◽  
Key Factor ◽  
Membrane Bound

ABSTRACTIt is well known that copper is a key factor regulating expression of the two forms of methane monooxygenase found in proteobacterial methanotrophs. Of these forms, the cytoplasmic, or soluble, methane monooxygenase (sMMO) is expressed only at low copper concentrations. The membrane-bound, or particulate, methane monooxygenase (pMMO) is constitutively expressed with respect to copper, and such expression increases with increasing copper. Recent findings have shown that copper uptake is mediated by a modified polypeptide, or chalkophore, termed methanobactin. Although methanobactin has high specificity for copper, it can bind other metals, e.g., gold. Here we show that inMethylosinus trichosporiumOB3b, sMMO is expressed and active in the presence of copper if gold is also simultaneously present. Such expression appears to be due to gold binding to methanobactin produced byM. trichosporiumOB3b, thereby limiting copper uptake. Such expression and activity, however, was significantly reduced if methanobactin preloaded with copper was also added. Further, quantitative reverse transcriptase PCR (RT-qPCR) of transcripts of genes encoding polypeptides of both forms of MMO and SDS-PAGE results indicate that both sMMO and pMMO can be expressed when copper and gold are present, as gold effectively competes with copper for binding to methanobactin. Such findings suggest that under certain geochemical conditions, both forms of MMO may be expressed and activein situ. Finally, these findings also suggest strategies whereby field sites can be manipulated to enhance sMMO expression, i.e., through the addition of a metal that can compete with copper for binding to methanobactin.

In-situ growth of ZIF-8 on gold nanoparticles/magnetic carbon nanotubes for electrochemical detection of bisphenol A

2021 ◽  
Author(s):  
Hexiang Li ◽  
Fawei Zhu ◽  
Jun Xiang ◽  
Fangbin Wang ◽  
Qi Liu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Gold Nanoparticles ◽  
Bisphenol A ◽  
Electrochemical Detection ◽  
Metal Organic Frameworks ◽  
In Situ Growth ◽  
Metal Organic ◽  
Magnetic Carbon ◽  
Magnetic Carbon Nanotubes

We herein report a facile and scalable strategy for fabrication of the metal organic frameworks (MOFs) based composite by in-situ growing ZIF-8 on the gold nanoparticles (AuNPs) loaded magnetic carbon...

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