scholarly journals Testing miniaturized electrodes for impedance measurements within the β-dispersion – a practical approach

2019 ◽  
Vol 1 (1) ◽  
pp. 41-55 ◽  
Author(s):  
Uwe Pliquett ◽  
Dieter Frense ◽  
Markus Schönfeldt ◽  
Christian Frätzer ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Quality Parameters ◽  
Electrode System ◽  
Electrode Impedance ◽  
Test Procedures ◽  
Quantitative Measurements ◽  
Current Voltage ◽  
Fluid Channel ◽  
Important Quality ◽  
Electrode Systems ◽  
Current Voltage Relation

Abstract Miniaturized electrodes are introduced in life sciences in a great number and variety. They are often designed for a special purpose without the need of quantitative analysis, such as for detecting cells or water droplets in a fluid channel. Other developments aim in monitoring a single quantity in a process where all other factors held constant. To use miniaturized electrodes for quantitative measurements, their behavior should be known in detail and stable over time in order to allow a mathematical correction of the data measured. Here we show test procedures for evaluating macroscopic but also microscopic electrodes. The most important quality parameters for electrode systems used in life science are the electrode impedance, its stability, the useful frequency range as well as the limits for applied stimulus without driving the electrode system into a non-linear region of the current/voltage relation. Proper electrode design allows a bandwidth from 100 Hz up to some MHz for impedances ranging over decades from 50 Ω up to several MΩ.

scholarly journals Water quality assessment of Owiwi River for potential irrigation of vegetables

2020 ◽  
Vol 39 (1) ◽  
pp. 293-300
Author(s):  
A.O. Eruola ◽  
A.A. Makinde ◽  
A.O. Eruola ◽  
R. Oladele
Keyword(s):  
Water Quality ◽  
Crop Production ◽  
Chemical Properties ◽  
Water Quality Assessment ◽  
Quality Parameters ◽  
Standard Test ◽  
Test Procedures ◽  
Salinity Hazard ◽  
Important Quality ◽  
Negative Impacts

Understanding water quality used for irrigation and its potential negative impacts on crop growth are important for optimization of crop production. The study involved the assessment of hydro-chemical properties and chemical indices of Owiwi river for irrigation of vegetables from the measured quality parameters and analyzed for important quality indices following standard test procedures. The study revealed that pH of water was acidic in nature resulting in low residual sodium carbonate (RSC) values showing dominance of dissolved CO3, attributed to dissolution of limestone dominant in the study area. The water was regarded as permissible water based on electrical conductivity (EC) and total dissolved solids (TDS), implying non detrimental salinity hazard in the soils. Excessive Na content (> 250 MMg/L) in water reduces the permeability thereby influencing availability of water for the plant usage, obviously associated with low EC and sodium adsorption ratio (SAR) observed in the river water. The excess hardness resulting from high content of calcium and magnesium ions derived from limestone and chalk is undesirable mostly for esthetic reasons like plumbing of irrigation systems. Generally, the water can be classified as good for irrigation of vegetable on the bases of PI, MAR, % Na, SAR and % yield. Keywords: Hydro-chemical, permeability, soil, limestone, yield.

PREPARASI DEINOCOCCUS RADIODURANS DAN KHAMIR DALAM MATERIAL KECAP L-DRYING SEBAGAI BAHAN UJI PROFISIENSI

2016 ◽  
Vol 13 (1) ◽  
pp. 93
Author(s):  
Titin Yulinery ◽  
Ratih M.Dewi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Deinococcus Radiodurans ◽  
Test Preparation ◽  
Quality Parameters ◽  
Soy Sauce ◽  
Yeast Saccharomyces Cerevisiae ◽  
Microbiological Test ◽  
Bacterial Contaminants ◽  
Minimum Number ◽  
Important Quality

Tes kemampuan adalah salah satu kegiatan penting dalam pengendalian mutu dan jaminan kualitas mikrobiologi laboratorium untuk mengukur kompetensi analis dan analisis uji profisiensi membutuhkan persiapan Model mikroorganisme adalah kualitas standar dan validitas. Mikrobiologi uji kualitas produk kedelai utama diarahkan pada kehadiran Saccharomyces cerevisiae ragi (S. cerevisiae), S. Bailli, S. rouxii dankontaminan bakteri seperti Bacillus dan Deinococcus. Jenis ragi dan bakteri yang terlibat dalam proses dan dapat menjadi salah satu parameter kualitas penting dalam persiapan yang dihasilkan. Jumlah dan viabilitas bakteri dan ragi menjadi parameter utama dalam proses persiapan bahan uji. Jumlah tersebut adalah jumlah minimum yang berlaku dapat dianalisis. Jumlah ini harus dibawah 10 CFU diperlukan untuk menunjukkan tingkat hygienitas proses dan tingkat minimal kontaminasi. Viabilitas bakteri dan bahan tes ragi persiapan untuk tes kemahiran kecap yang diawetkan dengan L-pengeringan adalah teknik Deinococcus radiodurans (D. radiodurans) 16 tahun, 58 tahun S. cerevisiae, dan S. roxii 13 tahun. kata kunci: Viabilitas, Deinococcus, khamir, L-pengeringan, Proficiency AbstractProficiency test is one of the important activities in quality control and quality assurance microbiology laboratory for measuring the competence of analysts and analysis Proficiency test requires a model microorganism preparations are standardized quality and validity. Microbiological test of the quality of the main soy products aimed at thepresence of yeast Saccharomyces cerevisiae (S. cerevisiae), S. bailli, S. rouxii and bacterial contaminants such as Bacillus and Deinococcus. Types of yeasts and bacteria involved in the process and can be one of the important quality parameters in the preparation produced. The number and viability of bacteria and yeasts become themain parameters in the process of test preparation materials. The amount in question is the minimum number that is valid can be analyzed. This amount must be below 10 CFU required to indicate the level of hygienitas process and the minimum level of contamination. Viability of bacteria and yeast test preparation materials for proficiencytest of soy sauce that preserved by L-drying technique is Deinococcus radiodurans ( D. radiodurans ) 16 years, 58 years S. cerevisiae, and S. roxii 13 years. key words : Viability, Deinococcus, Khamir, L-drying, Proficiency

Current‐voltage relation in a time‐dependent diode

1985 ◽  
Vol 47 (2) ◽  
pp. 115-117 ◽  
Author(s):  
Abraham Kadish ◽  
William Peter ◽  
Michael E. Jones
Keyword(s):  
Time Dependent ◽  
Current Voltage ◽  
Current Voltage Relation

scholarly journals Modeling Macroscopic Currents of Ion Channels

2021 ◽  
Author(s):  
Di Wu
Keyword(s):  
Open Channel ◽  
Single Channel ◽  
Ion Permeation ◽  
Model Studies ◽  
Proposed Model ◽  
Current Voltage ◽  
Improved Model ◽  
Boltzmann Model ◽  
Channel Properties ◽  
Current Voltage Relation

Ion-channel functions are often studied by the current-voltage relation, which is commonly fitted by the Boltzmann equation, a powerful model widely used nowadays. However, the Boltzmann model is restricted to a two-state ion-permeation process. Here we present an improved model that comprises a flexible number of states and incorporates both the single-channel conductance and the open-channel probability. Employing the channel properties derived from the single-channel recording experiments, the proposed model is able to describe various current-voltage relations, especially the reversal ion-permeation curves showing the inward- and outward-rectifications. We demonstrate the applicability of the proposed model using the published patch-clamp data of BK and MthK potassium channels, and discuss the similarity of the two channels based on the model studies.

Analysing of Harmonics Affecting the Energy Quality in Opium Alkaloids Plant's Power System

2016 ◽  
Vol 5 (4) ◽  
pp. 26-47
Author(s):  
Yüksel Oğuz ◽  
Mustafa Şahin ◽  
Yılmaz Güven ◽  
Hatice Zeliha Tuğcu
Keyword(s):  
Power Quality ◽  
Negative Impact ◽  
Energy System ◽  
Quality Parameters ◽  
International Standards ◽  
Opium Alkaloids ◽  
Current Voltage ◽  
Voltage Harmonics ◽  
Harmonic Filtering

The quality of energy has been defined to control harmonics caused by non-linear loads and international standards were brought to overcome the harmonic related problems. In determining the power quality, parameters like current-voltage harmonic, transient, flicker, current and voltage imbalance between phases, K factor are examined according to these international standards. The biggest disadvantage of harmonics is that they do not affect the power quality over an individual network but also affect the entire energy system primarily neighbouring facilities. Therefore, the energy system of Opium Alkaloids Plant was examined by using measurements information of current and voltage harmonics affecting the energy quality. And, it has been determined that the harmonics have a negative impact on energy quality. According to these findings, it has been proposed to install a well-designed filter for elimination of harmonics. Besides, it has been emphasised that new hardwares and devices should be chosen to support this harmonic filtering system in the future.

Nucleotide receptors activate cation, potassium, and chloride currents in a liver cell line

1994 ◽  
Vol 266 (4) ◽  
pp. G544-G553 ◽  
Author(s):  
J. G. Fitz ◽  
A. H. Sostman
Keyword(s):  
Nucleotide Receptors ◽  
Chloride Currents ◽  
Whole Cell Patch Clamp ◽  
Current Voltage ◽  
Htc Cells ◽  
Sequential Activation ◽  
Initial Activation ◽  
K Permeability ◽  
Current Voltage Relation ◽  
Sustained Activation

By use of whole cell patch-clamp techniques, the effects of extracellular ATP on membrane ion currents of HTC cells from a rat liver tumor line were evaluated. ATP (500 microM) or the nonhydrolyzable analogue adenosine 5'-O-(3-thiotriphosphate) caused sequential activation of three currents: Icat (-1,325 +/- 255 pA at -80 mV) occurred early, was due to increased Na+ and K+ permeability, was present in 56% of 64 consecutive cells, and rapidly inactivated; IK (274 +/- 45 pA at 0 mV) was present in 59% of cells and also inactivated; and ICl (1,172 +/- 237 pA at +60 mV) was present in 94% of studies, was sustained, and exhibited outward rectification of the current-voltage relation. All three currents were present in 39% of cells. Increasing intracellular Ca2+ concentration ([Ca2+]i) by exposure to the 5'-nucleotide receptor agonist UTP (500 microM) or to thapsigargin activated Icat and IK but not ICl, whereas increasing ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid in the pipette (> or = 5 mM) inhibited ATP-dependent activation of Icat and IK but not ICl. A P2x-preferring agonist alpha, beta-methylene ATP (500 microM) did not activate currents; a P2y-preferring agonist 2-methylthioadenosine triphosphate activated Icat and IK at concentrations of 500 microM but not 50 microM. In perforated patch recordings, ATP produced triphasic changes in membrane potential with initial depolarization due to Icat, subsequent hyperpolarization due to IK, and a later sustained depolarization due to ICl. These findings indicate that ATP modulates HTC cell ion permeability through initial activation of Icat and IK mediated by 5'-nucleotide receptors which mobilize [Ca2+], and sustained activation of ICl through a separate Ca(2+)-independent mechanism.

scholarly journals Optical control of the current-voltage relation in stacked superconductors

2019 ◽  
Vol 100 (13) ◽  
Author(s):  
Frank Schlawin ◽  
Anastasia S. D. Dietrich ◽  
Dieter Jaksch
Keyword(s):  
Optical Control ◽  
Current Voltage ◽  
Current Voltage Relation

scholarly journals Long-time resistivity monitoring of a freshwater/saltwater transition zone using the vertical electrode system SAMOS

2018 ◽  
Vol 54 ◽  
pp. 00009 ◽  
Author(s):  
Michael Grinat ◽  
Dieter Epping ◽  
Robert Meyer
Keyword(s):  
Transition Zone ◽  
Ground Level ◽  
Temporal Changes ◽  
Electrode System ◽  
The North ◽  
Vertical Electrode ◽  
Catchment Areas ◽  
Long Time ◽  
Pumping Rates ◽  
Electrode Systems

In September 2009 two newly developed vertical electrode systems were installed in boreholes in the water catchment areas Waterdelle and Ostland at the North Sea island Borkum to monitor possible changes of the transition zone between the freshwater lens and the underlying saltwater. The vertical electrode systems, which were both installed between 44 m and 65 m below ground level, are used for geoelectrical multi-electrode measurements carried out automatically several times per day; the measurements are still ongoing. The whole system consisting of a vertical electrode system in a borehole and the measuring unit at ground level is called SAMOS (Saltwater Monitoring System). At both locations the data show a clear resistivity decrease that indicates the transition zone between freshwater and saltwater. The depth of the transition zone as well as the kind of resistivity decrease is very stable since 2010. Temporal changes are visible if single depths are considered. In 2015 Miriam Ibenthal used a vertical 2D density-dependent groundwater flow model to explain the long-term resistivity measurements and showed that the temporal changes at CLIWAT 2 (Ostland) could be explained by variations of the groundwater level, changing groundwater recharge rates and changing pumping rates of the nearby located drinking water supply wells.

Current-voltage relation for abrupt N+-P-N+ and N-i-N structures

1992 ◽  
Vol 35 (7) ◽  
pp. 897-904 ◽  
Author(s):  
J.G.C. Bakker ◽  
J. Bisschop ◽  
W.H.A. Schilders
Keyword(s):  
Current Voltage ◽  
Current Voltage Relation

scholarly journals Post-colonoscopy colorectal cancer in Belgium: characteristics and influencing factors

2019 ◽  
Vol 07 (05) ◽  
pp. E717-E727 ◽  
Author(s):  
Elisabeth Macken ◽  
Stefan Van Dongen ◽  
Isabel De Brabander ◽  
Sven Francque ◽  
Ann Driessen ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Population Based ◽  
Quality Parameters ◽  
Quality Parameter ◽  
Medical Procedures ◽  
Polyp Detection ◽  
Quality Register ◽  
Polyp Detection Rate ◽  
Important Quality ◽  
Invasive Carcinomas

Abstract Background and study aims Post-colonoscopy colorectal cancer (PCCRC) is an important quality parameter of colonoscopy. Most studies have shown that the risk for colorectal cancer is reduced after an index colonoscopy for screening or diagnostic purposes with or without polypectomy. In this study, we aimed to quantify and describe PCCRC in Belgium, including the possible relationships with patient, physician, and colonoscopy characteristics. Patients and methods Reimbursement data on colorectal related medical procedures from the Intermutualistic Agency (IMA-AIM) were linked with data on clinical and pathological staging of colorectal cancer (CRC) available at the Belgian Cancer Registry (BCR) over a period covering 9 years (2002 – 2010). Results In total, 63 518 colorectal cancers were identified in 61 616 patients between 2002 and 2010. We calculated a mean PCCRC rate of 7.6 %. PCCRC was significantly higher in older people and correlated significantly with polyp detection rate and the number of resections and procedures performed per year per physician. Conditional observed survival, given still alive 3 years since first colonoscopy, for PCCRC was worse than for CRC. Older patients and patients with invasive carcinomas had a worse outcome. Conclusions Although no quality register exists in Belgium, we were able to demonstrate that PCCRC in Belgium is directly related to the experience of the physician performing the procedure. In the absence of a quality register, utilization of population-based data sources proved to be a valuable tool to identify quality parameters.

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