scholarly journals Application of Micropore Device for Accurate, Easy, and Rapid Discrimination of Saccharomyces pastorianus from Dekkera spp.

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 272
Author(s):  
Kazumichi Yokota ◽  
Asae Takeo ◽  
Hiroko Abe ◽  
Yuji Kurokawa ◽  
Muneaki Hashimoto ◽  
...  
Keyword(s):  
Ionic Current ◽  
Pulse Signal ◽  
Pulse Method ◽  
Recall Rate ◽  
Quantitative Detection ◽  
Current Response ◽  
Saccharomyces Pastorianus ◽  
Traceability Analysis ◽  
Rapid Discrimination ◽  
Low Sensitivity

Traceability analysis, such as identification and discrimination of yeasts used for fermentation, is important for ensuring manufacturing efficiency and product safety during brewing. However, conventional methods based on morphological and physiological properties have disadvantages such as time consumption and low sensitivity. In this study, the resistive pulse method (RPM) was employed to discriminate between Saccharomyces pastorianus and Dekkera anomala and S. pastorianus and D. bruxellensis by measuring the ionic current response of cells flowing through a microsized pore. The height and shape of the pulse signal were used for the simultaneous measurement of the size, shape, and surface charge of individual cells. Accurate discrimination of S. pastorianus from Dekkera spp. was observed with a recall rate of 96.3 ± 0.8%. Furthermore, budding S. pastorianus was quantitatively detected by evaluating the shape of the waveform of the current ionic blockade. We showed a proof-of-concept demonstration of RPM for the detection of contamination of Dekkera spp. in S. pastorianus and for monitoring the fermentation of S. pastorianus through the quantitative detection of budding cells.

scholarly journals Effect of Electrolyte Concentration on Cell Sensing by Measuring Ionic Current Waveform through Micropores

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 78
Author(s):  
Kazumichi Yokota ◽  
Muneaki Hashimoto ◽  
Kazuaki Kajimoto ◽  
Masato Tanaka ◽  
Sanae Murayama ◽  
...  
Keyword(s):  
Surface Charge ◽  
Cancer Cells ◽  
Electrolyte Solution ◽  
Electrolyte Concentration ◽  
Ionic Current ◽  
Pulse Signal ◽  
Cancer Prognosis ◽  
Detection Methods ◽  
Quantitative Detection ◽  
Current Response

Immunostaining has been widely used in cancer prognosis for the quantitative detection of cancer cells present in the bloodstream. However, conventional detection methods based on the target membrane protein expression exhibit the risk of missing cancer cells owing to variable protein expressions. In this study, the resistive pulse method (RPM) was employed to discriminate between cultured cancer cells (NCI-H1650) and T lymphoblastoid leukemia cells (CCRF-CEM) by measuring the ionic current response of cells flowing through a micro-space. The height and shape of a pulse signal were used for the simultaneous measurement of size, deformability, and surface charge of individual cells. An accurate discrimination of cancer cells could not be obtained using 1.0 × phosphate-buffered saline (PBS) as an electrolyte solution to compare the size measurements by a microscopic observation. However, an accurate discrimination of cancer cells with a discrimination error rate of 4.5 ± 0.5% was achieved using 0.5 × PBS containing 2.77% glucose as the electrolyte solution. The potential application of RPM for the accurate discrimination of cancer cells from leukocytes was demonstrated through the measurement of the individual cell size, deformability, and surface charge in a solution with a low electrolyte concentration.

scholarly journals Research on Mud Pulse MWD Device for Mines

2021 ◽  
Vol 248 ◽  
pp. 03050
Author(s):  
Gao Jun
Keyword(s):  
Signal Transmission ◽  
Drill Pipe ◽  
Pulse Signal ◽  
Pulse Method ◽  
Directional Drilling ◽  
Transmission Distance ◽  
Signal Encoding ◽  
Measurement While Drilling ◽  
Working Principle ◽  
Encoding Method

As the core accoutrement of directional drilling construction, the measurement while drilling (MWD) device can be divided into three types due to the different data transmission methods: wired, mud pulse and electromagnetic wave. This paper used the mud pulse method to develop a mud pulse MWD device for mines, and the working principle of the mud pulse signal transmission, the signal encoding method and the structure of the device were described. Experimental research showed that the mud pulse wireless MWD device had the advantages of long transmission distance and strong working stability. At the same time, the device was not restricted by the drill pipe during operation, which could be combined with sliding orientation and rotary feed, and had great promotion and application value.

scholarly journals High resolution melting assay in discrimination of the main etiologic agents of leishmaniasis in Iran

2021 ◽  
Author(s):  
Shima Fayaz ◽  
Pezhman Fard-Esfahani ◽  
Fariborz Bahrami ◽  
Parviz Parvizi ◽  
Soheila Ajdary
Keyword(s):  
High Resolution ◽  
High Resolution Melting ◽  
Leishmania Species ◽  
Old World ◽  
Hrm Analysis ◽  
Etiologic Agents ◽  
Pcr Method ◽  
Etiological Agents ◽  
Rapid Discrimination ◽  
Low Sensitivity

Background and Objectives: The three old world Leishmania species i.e., L. major, L. tropica, and L. infantum are considered as potential etiological agents of the various clinical forms of leishmaniasis in Iran. Different species co-exist in some areas. Accurate differentiation between the species is essential for choosing an appropriate therapy. Conventional and gold standard methods for the detection and characterization of parasites are time-consuming, laborious, and have low sensitivity. A polymerase chain reaction followed by high resolution melting (PCR-HRM) analysis has been employed for detection and species identification. Most of the studies suffer from the use of multiple targets and/ or requiring more than one reaction to identify a single sample. The present study aimed to design a PCR method based on the amplification of kinetoplast DNA minicircles (kDNA) and HRM analysis of the amplicons for rapid discrimination of the three mentioned species. Materials and Methods: DNA from reference strains including L. major, L. tropica, and L. infantum and fifty-eight strains subjected to PCR-HRM analysis targeting kDNA. All the samples were also analyzed by conventional kDNA- PCR. Results: The PCR-HRM analysis allowed discrimination between the three Old World species. The normalized HRM curves for the amplicons of kDNA indicated a unique and repeatable melting plot for each species, even in combination with human and mouse genomic DNA. Conventional kDNA- PCR could not properly discriminate L. tropica from L. infantum. Conclusion: PCR- HRM analysis of kDNA proved to be fast and accurate for discrimination of L. major, L. tropica, and L. infantum.

scholarly journals Insulator filth monitoring and situation awareness based on ultraviolet pulse and least square method

2021 ◽  
Vol 2108 (1) ◽  
pp. 012056
Author(s):  
Tao Liu ◽  
Bo Qu ◽  
Guolong Li
Keyword(s):  
Visible Light ◽  
Situation Awareness ◽  
Pulse Signal ◽  
Signal Amplitude ◽  
Pulse Method ◽  
Least Square ◽  
Electrical Pulse ◽  
Image Size ◽  
Observation Distance ◽  
Spot Area

Abstract To monitor the filth state of insulators in time, a method based on ultraviolet pulse method is proposed to monitor the filth status of insulators, which can detect the early corona discharge of insulators by detecting UV signals and determine the degree of insulator filth. On this basis, the response characteristics of spot area to electrical pulse signal are studied and theoretical analysis is carried out, the relationship between spot area and electrical pulse signal amplitude is studied, and the correlation curve is obtained. By observing the change law of image size with the observation distance in ultraviolet image. the experiment found that the image size of UV channel and the image size of visible light channel increased or decreased in approximate proportion with the observation distance and proposed a new method to estimate the “discharge imaging area ” of discharge on the surface of the insulator by using the image information of the visible light channel. According to the discharge “relative spot area mean”, one minute time “number of large spot area image frames” two ultraviolet imaging parameters used to characterize the filth discharge characteristics, combined with the ambient humidity to establish a fuzzy logic reasoning model of the filth state, to achieve the assessment of the filth state of the insulator. By using the proposed UV image processing method, the accuracy of insulator filth detection is improved.

Acid-Sensing Ionic Channels in the Rat Vestibular Endorgans and Ganglia

2006 ◽  
Vol 96 (3) ◽  
pp. 1615-1624 ◽  
Author(s):  
Francisco Mercado ◽  
Iván A. López ◽  
Dora Acuna ◽  
Rosario Vega ◽  
Enrique Soto
Keyword(s):  
Pain Perception ◽  
Ionic Current ◽  
Ionic Channels ◽  
Functional Expression ◽  
Current Response ◽  
Afferent Neurons ◽  
Peripheral Tissues ◽  
Vestibular Ganglion ◽  
Vestibular Endorgans ◽  
Ganglion Neurons

Acid-sensing ionic channels (ASICs) are members of the epithelial Na+ channel/degenerin (ENaC/DEG) superfamily. ASICs are widely distributed in the central and peripheral nervous system. They have been implicated in synaptic transmission, pain perception, and the mechanoreception in peripheral tissues. Our objective was to characterize proton-gated currents mediated by ASICs and to determine their immunolocation in the rat vestibular periphery. Voltage clamp of cultured afferent neurons from P7 to P10 rats showed a proton-gated current with rapid activation and complete desensitization, which was carried almost exclusively by sodium ions. The current response to protons (H+) has a pH0.5 of 6.2. This current was reversibly decreased by amiloride, gadolinium, lead, acetylsalicylic acid, and enhanced by FMRFamide and zinc, and negatively modulated by raising the extracellular calcium concentration. Functional expression of the current was correlated with smaller-capacitance neurons. Acidification of the extracellular pH generated action potentials in vestibular neurons, suggesting a functional role of ASICs in their excitability. Immunoreactivity to ASIC1a and ASIC2a subunits was found in small vestibular ganglion neurons and afferent fibers that run throughout the macula utricle and crista stroma. ASIC2b, ASIC3, and ASIC4 were expressed to a lesser degree in vestibular ganglion neurons. The ASIC1b subunit was not detected in the vestibular endorgans. No acid-pH–sensitive currents or ASIC immunoreactivity was found in hair cells. Our results indicate that proton-gated current is carried through ASICs and that ionic current activated by H+ contributes to shape the vestibular afferent neurons' response to its synaptic input.

Monitoring the Cardiovascular Changes of a Rabbit Caused by Phenylephrine via a Microfluidic-Based Tactile Sensor

2019 ◽  
Author(s):  
Dan Wang ◽  
Frank A. Lattanzio ◽  
Mario C. Rodriguez ◽  
Zhili Hao
Keyword(s):  
Blood Pressure ◽  
Elastic Modulus ◽  
Pulse Signal ◽  
High Sensitivity ◽  
Tactile Sensor ◽  
Arterial Pulse ◽  
Record Blood Pressure ◽  
Baseline Values ◽  
Low Sensitivity ◽  
Model Based Analysis

Abstract In this work, a microfluidic-based tactile sensor was investigated for monitoring changes in the cardiovascular (CV) system of a rabbit caused by phenylephrine. The sensor was fixed on the front right leg of an anesthetized rabbit to measure the arterial pulse signal. Phenylephrine, as a vasoconstrictor, was used to introduce CV changes of the rabbit. Two sensors, one with high sensitivity and the other with low sensitivity, were tested on their suitability for measuring the pulse signals of the rabbit. The sensor with low sensitivity generated clear pulse signals and was further used to monitor the CV changes of the rabbit caused by phenylephrine. An automated sphygmomanometer and an ECG were used to record blood pressure and heart rate for comparison. Three low-dose injections of phenylephrine were sequentially performed on the rabbit. Through model-based analysis of the measured pulse signals, arterial elastic modulus, arterial radius and pulse wave velocity (PWV) were obtained. As compared with the baseline values measured before injection, injections of phenylephrine caused an increase in mean blood pressure (MAP) recorded by the medical instruments, and a decrease in arterial radius (increase in peripheral vascular resistance (PVR)) and an increase in arterial elastic modulus and PWV captured by the tactile sensor. Thus, the tactile sensor was proven to be feasible for monitoring the changes in the CV system caused by phenylephrine.

scholarly journals Rapid Detection of Norovirus Using Paper-based Microfluidic Device

2017 ◽  
Author(s):  
Xuan Weng ◽  
Suresh Neethirajan
Keyword(s):  
Microfluidic Device ◽  
Point Of Care ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Cost Effective ◽  
Quantitative Detection ◽  
Multi Walled Carbon Nanotubes ◽  
Low Sensitivity ◽  
Walled Carbon Nanotubes ◽  
Analytical Approaches

AbstractNoroviruses (NoV) are the leading cause of outbreak of acute gastroenteritis worldwide. A substantial effort has been made in the development of analytical devices for rapid and sensitive food safety monitoring via the detection of foodborne bacteria, viruses and parasites. Conventional analytical approaches for noroviruses suffer from some critical weaknesses: labor-intensive, time-consuming, and relatively low sensitivity. In this study, we developed a rapid and highly sensitive biosensor towards point-of-care device for noroviruses based on 6-carboxyfluorescein (6-FAM) labeled aptamer and nanomaterials, multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO). In an assay, the fluorescence of 6-FAM labeled aptamer was quenched by MWCNTs or GO via fluorescence resonance energy transfer (FRET). In the presence of norovirus, the fluorescence would be recovered due to the release of the 6-FAM labeled aptamer from MWCNTs or GO. An easy-to-make paper-based microfluidic platform made by nitrocellulose membrane was used to conduct the assay. The quantitative detection of norovirus virus-like particles (NoV VLPs) was successfully performed. A linear range of 0-12.9 μg/mL with a detection limit of 40 pM and 30 pM was achieved for the MWCNTs and GO based paper sensors, respectively. The results suggested the developed paper-based microfluidic device is simple, cost-effective and holds the potential of rapid in situ visual determination for noroviruses with remarkable sensitivity and specificity, which provides a new way for early identification of NoV and thereby an early intervention for preventing the spread of an outbreak.

Design of a Novel Excitation Circuit for Low Perming Error Fluxgate

2013 ◽  
Vol 748 ◽  
pp. 859-863
Author(s):  
Zhi Jun Cui
Keyword(s):  
Power Consumption ◽  
Pulse Signal ◽  
High Ratio ◽  
Pulse Excitation ◽  
Current Waveform ◽  
Excitation Current ◽  
Low Sensitivity ◽  
Excitation Waveform ◽  
Excitation Circuit ◽  
Peak Value

An effective method for low perming error of fluxgates is to enlarge the peak value of the excitation current, but large amplitude excitation will increase the power consumption. A narrow pulse excitation current with sufficient peak value can reduce perming error with low power consumption while increase the difficulty of the signal processing with low sensitivity. The perfected excitation waveform with high ratio of peak value to RMS value by careful excitation tuning is an efficient solution. This paper presents a novel circuit which can generate an excitation current waveform with high peak value and low RMS value for fluxgates. Different from the tuned excitation circuit, the proposed circuit is a combination of an integrator and a differentiator with the same squarewave input. The excitation signal is the sum of a triangle wave and a sharp narrow pulse signal. It is easy to adjust the peak value of the narrow pulses for perming error study and no careful tune adjusting is needed. Finally, in case of the fixed peak value of the narrow pulses, an improved excitation circuit with only two resistors, two capacitors and one amplifier is also presented in the paper. The experiment results show that 0.5nT perming error can be achieved for 10mT shock.

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