Electronic device for microelectrode recordings in epithelial cells

1984 ◽  
Vol 246 (3) ◽  
pp. C339-C346 ◽  
Author(s):  
J. F. Garcia-Diaz ◽  
S. Stump ◽  
W. M. Armstrong
Keyword(s):  
Continuous Monitoring ◽  
Electronic Device ◽  
Voltage Drop ◽  
Membrane Damage ◽  
Open Circuit ◽  
Salt Bridges ◽  
Current Pulses ◽  
A Cell ◽  
Tip Potential ◽  
The Individual

A device is described that permits continuous measurement of electrophysiological parameters in epithelial tissues in the open-circuit mode. Transepithelial potential (VT) and microelectrode (either conventional or ion-selective) potential (VM) are directly measured. Application of transepithelial current pulses allows continuous monitoring of transepithelial resistance (RT) and the ratio between the changes in VM and VT induced by these pulses. Measurement of this ratio, which under some circumstances reflects the apical fractional resistance of the cellular pathway, is important in assessing membrane damage during microelectrode impalement and/or as an index that the microelectrode tip is inside a cell. This is particularly useful when the change in VM during impalement is small. Application of 0.5-nA current pulses through open-tip microelectrodes allows continuous recording of the microelectrode resistance (RM). In epithelia where the individual cells are electrically coupled this permits acceptable impalements (RM remains nearly constant) to be distinguished from those affected by tip potential artifacts due to plugging of the microelectrode tip (RM increases after penetration of the cell membrane). The device provides compensation for the IR voltage drop in the solution between the potential measuring salt bridges and the epithelial surfaces. The microelectrode electrometer has an input impedance greater than 10(15) and is provided with stray capacitance neutralization.

Nonspecific Chronic Back Pain: Sixth Edition Approaches

2019 ◽  
Vol 24 (5) ◽  
pp. 14-15
Author(s):  
Jay Blaisdell ◽  
James B. Talmage
Keyword(s):  
Back Pain ◽  
Chronic Back Pain ◽  
Intervertebral Disk ◽  
Key Factors ◽  
Sixth Edition ◽  
Whole Person ◽  
Class 1 ◽  
A Cell ◽  
Intervertebral Disk Herniation ◽  
The Individual

Abstract Ratings for “non-specific chronic, or chronic reoccurring, back pain” are based on the diagnosis-based impairment method whereby an impairment class, usually representing a range of impairment values within a cell of a grid, is selected by diagnosis and “specific criteria” (key factors). Within the impairment class, the default impairment value then can be modified using non-key factors or “grade modifiers” such as functional history, physical examination, and clinical studies using the net adjustment formula. The diagnosis of “nonspecific chronic, or chronic reoccurring, back pain” can be rated in class 0 and 1; the former has a default value of 0%, and the latter has a default value of 2% before any modifications. The key concept here is that the physician believes that the patient is experiencing pain, yet there are no related objective findings, most notably radiculopathy as distinguished from “nonverifiable radicular complaints.” If the individual is found not to have radiculopathy and the medical record shows that the patient has never had clinically verifiable radiculopathy, then the diagnosis of “intervertebral disk herniation and/or AOMSI [alteration of motion segment integrity] cannot be used.” If the patient is asymptomatic at maximum medical improvement, then impairment Class 0 should be chosen, not Class 1; a final whole person impairment rating of 1% indicates incorrect use of the methodology.

scholarly journals Visualizing the Bohr effect in hemoglobin: neutron structure of equine cyanomethemoglobin in the R state and comparison with human deoxyhemoglobin in the T state

2016 ◽  
Vol 72 (7) ◽  
pp. 892-903 ◽  
Author(s):  
Steven Dajnowicz ◽  
Sean Seaver ◽  
B. Leif Hanson ◽  
S. Zoë Fisher ◽  
Paul Langan ◽  
...  
Keyword(s):  
Structural Changes ◽  
Accurate Determination ◽  
Bohr Effect ◽  
Salt Bridges ◽  
Histidine Residues ◽  
Regions Of Stability ◽  
The Individual ◽  
T State

Neutron crystallography provides direct visual evidence of the atomic positions of deuterium-exchanged H atoms, enabling the accurate determination of the protonation/deuteration state of hydrated biomolecules. Comparison of two neutron structures of hemoglobins, human deoxyhemoglobin (T state) and equine cyanomethemoglobin (R state), offers a direct observation of histidine residues that are likely to contribute to the Bohr effect. Previous studies have shown that the T-state N-terminal and C-terminal salt bridges appear to have a partial instead of a primary overall contribution. Four conserved histidine residues [αHis72(EF1), αHis103(G10), αHis89(FG1), αHis112(G19) and βHis97(FG4)] can become protonated/deuterated from the R to the T state, while two histidine residues [αHis20(B1) and βHis117(G19)] can lose a proton/deuteron. αHis103(G10), located in the α1:β1dimer interface, appears to be a Bohr group that undergoes structural changes: in the R state it is singly protonated/deuterated and hydrogen-bonded through a water network to βAsn108(G10) and in the T state it is doubly protonated/deuterated with the network uncoupled. The very long-term H/D exchange of the amide protons identifies regions that are accessible to exchange as well as regions that are impermeable to exchange. The liganded relaxed state (R state) has comparable levels of exchange (17.1% non-exchanged) compared with the deoxy tense state (T state; 11.8% non-exchanged). Interestingly, the regions of non-exchanged protons shift from the tetramer interfaces in the T-state interface (α1:β2and α2:β1) to the cores of the individual monomers and to the dimer interfaces (α1:β1and α2:β2) in the R state. The comparison of regions of stability in the two states allows a visualization of the conservation of fold energy necessary for ligand binding and release.

scholarly journals Photosensitization to ultraviolet irradiation and selective killing of cells following uptake of pyrene-containing fatty acid

1986 ◽  
Vol 85 (1) ◽  
pp. 149-159
Author(s):  
E. Fibach ◽  
O. Morand ◽  
S. Gatt
Keyword(s):  
Fatty Acid ◽  
Ultraviolet Irradiation ◽  
Plasma Membranes ◽  
Incubation Temperature ◽  
Serum Proteins ◽  
Neutral Lipids ◽  
Cell Types ◽  
Dodecanoic Acid ◽  
A Cell ◽  
The Individual

Cells were incubated with 12-(1-pyrene)-dodecanoic acid (P12), a long-chain fatty acid to which a pyrene ring has been attached covalently. This acid was transported across the plasma membranes of cells and subsequently incorporated into their neutral lipids and phospholipids. Irradiation of these pyrene-containing cells for short periods (0.5-4 min) with ultraviolet light at 366 nm resulted in eventual cell death. Similar irradiation had no effect on cells that had not been exposed to P12. The time of the period of irradiation necessary for inducing the toxic process was related to the quantity of P12 incorporated, the latter being a function of the respective metabolic activity of the individual cell type. The degree of incorporation of P12 into a cell, and consequently its acquired sensitivity to killing by ultraviolet irradiation at 366 nm, was affected by the incubation temperature and addition of non-fluorescent fatty acid, albumin or other serum proteins. Different degrees of incorporation of P12 into various cell types were used for selective killing and elimination of cell populations by irradiation at 366 nm. The combined procedure of preincubation with P12 followed by ultraviolet irradiation thus permitted selection of cell types with a greater resistance to this procedure.

Development of Portable Medical Electronic Device for Infant Cry Recognition

2016 ◽  
Vol 5 (2) ◽  
pp. 53-63 ◽  
Author(s):  
Natarajan Sriraam ◽  
S. Tejaswini ◽  
Ankita Arun Chavan
Keyword(s):  
Experimental Study ◽  
Continuous Monitoring ◽  
Electronic Device ◽  
Term Infants ◽  
Significant Information ◽  
Infant Cry ◽  
Physiological Conditions ◽  
Medical Electronic ◽  
Voice Recorder ◽  
The Voice

Infant cry is considered as the first biological signal communicated by the newborns to the mother and the outside world. In NICU, there is a huge need to monitor the physiological conditions of the premature and full term infants. In such environment, the cry signal conveys significant information in terms of the distress of the infant and thereby needs of the infants can be well attended. Establishment of the portable device is thus essential for such scenario. This work enumerates a primitive experimental study on developing portable electronic medical device for infant cry recognition. The setup comprises of a voice recorder, NI My RIO processor with a Lab view followed by the LCD Tablet for display. The cry signals were recorded by placing the voice recorder in the incubator and were qualitatively assessed by the clinician and confirm its suitability for the experimental study. A threshold based classification was employed which sends the voice based alarm to the tablet. The continuous monitoring of such facility in NICU provides the behavioral status of the infant

scholarly journals Parameterization and Validation of an Electrochemical Thermal Model of a Lithium-Ion Battery

Batteries ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 62 ◽  
Author(s):  
Liebig ◽  
Gupta ◽  
Kirstein ◽  
Schuldt ◽  
Agert
Keyword(s):  
Lithium Ion Battery ◽  
Heat Dissipation ◽  
Electrochemical Impedance ◽  
Coupled Model ◽  
Lithium Ion ◽  
Open Circuit ◽  
Battery Cell ◽  
Model Parameterization ◽  
Parameterized Model ◽  
The Individual

The key challenge in developing a physico-chemical model is the model parameterization. The paper presents a strategic model parameterization procedure, parameter values, and a developed model that allows simulating electrochemical and thermal behavior of a commercial lithium-ion battery with high accuracy. Steps taken are the analysis of geometry details by opening a battery cell under argon atmosphere, building upon reference data of similar material compositions, incorporating cell balancing by a quasi-open-circuit-voltage experiment, and adapting the battery models reaction kinetics behavior by comparing experiment and simulation of an electrochemical impedance spectroscopy and hybrid pulse power characterization. The electrochemical-thermal coupled model is established based on COMSOL Multiphysics® platform (Stockholm, Sweden) and validated via experimental methods. The parameterized model was adopted to analyze the heat dissipation sources based on the internal states of the battery at different operation modes. Simulation in the field of thermal management for lithium-ion batteries highly depends on state of charge-related thermal issues of the incorporated cell composition. The electrode balancing is an essential step to be performed in order to address the internal battery states realistically. The individual contribution of the cell components heat dissipation has significant influence on the temperature distribution pattern based on the kinetic and thermodynamic properties.

scholarly journals Fault Diagnosis of Open-Switch Failure in a Grid-Connected Three-Level Si/SiC Hybrid ANPC Inverter

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 399 ◽  
Author(s):  
Bong Hyun Kwon ◽  
Sang-Hun Kim ◽  
Seok-Min Kim ◽  
Kyo-Beum Lee
Keyword(s):  
Diagnostic Method ◽  
Field Effect Transistors ◽  
Open Circuit ◽  
Bipolar Transistors ◽  
Neutral Point ◽  
Oxide Semiconductor ◽  
Short Period ◽  
Open Switch ◽  
Stationary Reference Frame ◽  
The Individual

A diagnostic method for an open-circuit switch failure in a hybrid active neutral-point clamped (HANPC) inverter is proposed in this paper. The switching leg of the HANPC inverter consists of four silicon insulated gate bipolar transistors and two silicon carbide metal-oxide-semiconductor field-effect transistors to achieve higher efficiency and power density compared to conventional neutral-point clamped inverters. When an open-circuit failure occurs in a switching device, the output current is severely distorted, causing damage to the inverter and the connected loads. The proposed diagnostic method aims to detect the open-switch failure and protect the related devices without additional sensors or circuits. The faulty conditions of six different switches are investigated based on the current distortion in the stationary reference frame. By analyzing the individual characteristic of each switch failure, it is possible to detect the exact location of the failed switch in a short period. The effectiveness and feasibility of the proposed fault-diagnostic method are verified using simulation and experimental results.

The ultrastructure of Methanothrix concilii, a mesophilic aceticlastic methanogen

1986 ◽  
Vol 32 (9) ◽  
pp. 703-710 ◽  
Author(s):  
Terry J. Beveridge ◽  
Girish B. Patel ◽  
Bob J. Harris ◽  
G. Dennis Sprott
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Circular Plates ◽  
A Cell ◽  
Granular Matrix ◽  
A Chain ◽  
The Individual

Methanothrix concilii strain GP6 consists of a chain of rod-shaped cells, ca. 2.5 μm in length and 0.8 μm in width, which are encased in a tubular proteinaceous sheath. The sheath is composed of annular hoops, ca. 8.0 nm wide and 9.0 nm thick, which are stacked together to form the tube. The ends of the sheath, and therefore the cell filament, are blocked by single, multilayered, 13.5 nm thick, circular plates, designated as "spacer plugs," which contain a series of concentric rings; these also separate the individual cells within each filament. Each cell is therefore bounded by a tubular section of sheath and two spacer plugs. Completely encapsulating each cell, and lying between the sheath and cell, is an amorphous granular matrix. Overlying the plasma membrane and surrounding each protoplast is a thin veil of material which resembles a cell wall, but which is unable to maintain the rod shape when cells are extruded from the sheath.

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