Molecular Motor and Electrokinetic Contributions to Outer Hair Cell Electromotility

1998 ◽  
Vol 79 (1) ◽  
pp. 471-473 ◽  
Author(s):  
Rocco A. Jerry ◽  
Ashim Dutta
Keyword(s):  
Hair Cell ◽  
Molecular Motors ◽  
Outer Hair Cell ◽  
Motor Behavior ◽  
Molecular Motor ◽  
High Sensitivity ◽  
Length Change ◽  
The Novel ◽  
Sensitivity And Selectivity ◽  
A New Technique

Jerry, Rocco A. and Ashim Dutta. Molecular motor and electrokinetic contributions to outer hair cell electromotility. J. Neurophysiol. 79: 471–473, 1998. The outer hair cell of the inner ear is believed to be responsible for the high sensitivity and selectivity of mammalian hearing. Molecular motors are generally believed to cause the electrically-driven length change (electromotility) of the outer hair cell. It has been suggested that electrokinetic effects might also play a significant role in electromotility, along with the molecular motors. This paper describes a new technique that can be used to experimentally determine the percentage of the electromotile response that is caused by electrokinetic effects. The technique is based on the novel idea that molecular motor activity cannot in itself generate a net force on the cell, but that electrokinetic effects can. Our method is the first that can separate molecular motor behavior from electrokinetic behavior, during experiments on the outer hair cell.

Effectiveness, Active Energy Produced by Molecular Motors, and Nonlinear Capacitance of the Cochlear Outer Hair Cell

2005 ◽  
Vol 127 (3) ◽  
pp. 391-399 ◽  
Author(s):  
Alexander A. Spector
Keyword(s):  
Hair Cell ◽  
Molecular Motors ◽  
Outer Hair Cell ◽  
Molecular Motor ◽  
Force Production ◽  
Outer Hair Cells ◽  
Nonlinear Capacitance ◽  
Effective Capacitance ◽  
Capacitive Properties ◽  
Length Changes

Cochlear outer hair cells are crucial for active hearing. These cells have a unique form of motility, named electromotility, whose main features are the cell’s length changes, active force production, and nonlinear capacitance. The molecular motor, prestin, that drives outer hair cell electromotility has recently been identified. We reveal relationships between the active energy produced by the outer hair cell molecular motors, motor effectiveness, and the capacitive properties of the cell membrane. We quantitatively characterize these relationships by introducing three characteristics: effective capacitance, zero-strain capacitance, and zero-resultant capacitance. We show that zero-strain capacitance is smaller than zero-resultant capacitance, and that the effective capacitance is between the two. It was also found that the differences between the introduced capacitive characteristics can be expressed in terms of the active energy produced by the cell’s molecular motors. The effectiveness of the cell and its molecular motors is introduced as the ratio of the motors’ active energy to the energy of the externally applied electric field. It is shown that the effectiveness is proportional to the difference between zero-strain and zero-resultant capacitance. We analyze the cell and motor’s effectiveness within a broad range of cellular parameters and estimate it to be within a range of 12%–30%.

scholarly journals Chromatographic Methods for the Determination of Aminexil, Pyridoxine, and Niacinamide in a Novel Cosmetic Hair Preparation

2020 ◽  
Vol 103 (4) ◽  
pp. 1167-1172
Author(s):  
Mamdouh R Rezk ◽  
Hebatallah M Essam ◽  
Enas A Amer ◽  
Dina M S Youssif
Keyword(s):  
High Performance ◽  
High Sensitivity ◽  
Ammonia Solution ◽  
Hplc Method ◽  
The Novel ◽  
Chromatographic Methods ◽  
Ich Guidelines ◽  
Sensitivity And Selectivity ◽  
Keratin Fibers

Abstract Background Aminexil, a new compound patented by L’Oreal, has a stimulating effect on human keratin fibers. Pyridoxine HCl and niacinamide are added to boost the hair tonic effect of aminexil. Objective Two novel chromatographic methods were developed for the determination of aminexil (AX), niacinamide (NA) and pyridoxine HCl (PD) in the novel hair tonic preparation. Methods The developed methods were high-performance liquid chromatography (HPLC) and thin layer chromatography (TLC) with densitometric determination. Different experimental parameters were investigated and optimized to achieve complete baseline separation and well resolved peaks. The RP-HPLC separation was achieved using a Thermoscientific BDS hypersil C18 (250 × 4.6 mm, 5 µm) column using 0.005 M hexane sulfonic acid: methanol (80: 20, v/v) as a mobile phase. For the TLC method, the three analytes were partitioned between propanol: toluene: ammonia solution (40:60:2, v/v/v) and fluorescent silica plates. The two methods were validated in compliance with International Conference on Harmonization (ICH) guidelines. The obtained data were statistically analyzed to confirm the existing results. The developed methods were successfully applied for determination of the studied drugs in pure forms and in the cosmetic preparation. Results For the HPLC method, the RSDs of AX, NA and PD were 0.70, 0.88 and 1.17 respectively. For the TLC method, the RSDs of AX, NA and PD were 1.06, 1.37 and 0.73 respectively. Conclusions The proposed chromatographic methods showed high sensitivity and selectivity for the three compounds under analysis in the laboratory prepared mixture and in the hair tonic preparation. Highlights Aminexil, Pyridoxine, Niacinamide, HPLC. The present work offers two reproducible, accurate, validated, time and cost saving alternatives for the quantitative and qualitative determination of medicated hair preparation.

scholarly journals The Use of Chemically Precipitated Lead Sulfide Thin Films as a Material for Sensors Meant for Lead Content in Water Media Control

2011 ◽  
pp. 64-73
Author(s):  
Keyword(s):  
Thin Films ◽  
Lead Sulfide ◽  
High Sensitivity ◽  
Ion Selective Electrodes ◽  
Analytical Control ◽  
The Novel ◽  
Media Control ◽  
Primary Converter ◽  
Water Media ◽  
Sensitivity And Selectivity

Surface-sensitive properties of the sensor elements based on semiconductor thin fills of lead sulfide have been studied in order to use them as primary converter for ecological/analytical control of water media. Distinctive feater of the novel sensor elements is their high sensitivity and selectivity that five and more times exceeds similar properties of commercial ion-selective electrodes.

scholarly journals Amperometric Biosensors for L-Arginine Determination Based on L-Arginine Oxidase and Peroxidase-Like Nanozymes

2021 ◽  
Vol 11 (15) ◽  
pp. 7024
Author(s):  
Nataliya Stasyuk ◽  
Galina Gayda ◽  
Olha Demkiv ◽  
Lyubomyr Darmohray ◽  
Mykhailo Gonchar ◽  
...  
Keyword(s):  
Pharmaceutical Preparation ◽  
Enzymatic Reaction ◽  
High Sensitivity ◽  
The Novel ◽  
Limited Data ◽  
Amperometric Biosensors ◽  
Graphite Electrodes ◽  
Sensitivity And Selectivity ◽  
The Cost

There are limited data on amperometric biosensors (ABSs) for L-arginine (Arg) determination based on oxidases that produce hydrogen peroxide (H2O2) as a byproduct of enzymatic reaction, and artificial peroxidases (POs) for decomposition of H2O2. The most frequently proposed Arg-sensitive oxidase-based ABSs contain at least two enzymes in the bioselective layer; this complicates the procedure and increases the cost of analysis. Therefore, the construction of a one-enzyme ABS for Arg analysis is a practical problem. In the current work, fabrication, and characterization of three ABS types for the direct measurement of Arg were proposed. L-arginine oxidase (ArgO) isolated from the mushroom Amanita phalloides was co-immobilized with PO-like nanozymes (NZs) on the surface of graphite electrodes. As PO mimetics, chemically synthesized NZs of CeCu (nCeCU) and NiPtPd (nNiPtPd), as well as green-synthesized hexacyanoferrate of copper (gCuHCF), were used. The novel ABSs exhibited high sensitivity and selectivity to Arg, broad linear ranges and good storage stabilities. Two ABSs were tested on real samples of products containing Arg, including the pharmaceutical preparation “Tivortine”, juices, and wine. A high correlation (R = 0.995) was demonstrated between the results of testing “Tivortine” and juice using nCeCU/GE and nNiPtPd/GE. It is worth mentioning that only a slight difference (less than 1%) was observed for “Tivortin” between the experimentally determined content of Arg and its value declared by the producer. The proposed ArgO-NZ-based ABSs may be promising for Arg analysis in different branches of science, medicine, and industry.

Schottky diodes based on 2D materials for environmental gas monitoring: a review on emerging trends, recent developments and future perspectives

2021 ◽  
Author(s):  
Minu Mathew ◽  
Chandra Sekhar Rout
Keyword(s):  
Gas Sensing ◽  
2D Materials ◽  
Schottky Diodes ◽  
High Sensitivity ◽  
Future Perspectives ◽  
Working Temperature ◽  
Emerging Trends ◽  
Gas Sensing Properties ◽  
Recent Developments ◽  
Sensitivity And Selectivity

This review details the fundamentals, working principles and recent developments of Schottky junctions based on 2D materials to emphasize their improved gas sensing properties including low working temperature, high sensitivity, and selectivity.

Direct Read and Quantify Damage Nucleotide from an Oligonucleotide Using a Single Molecule Interface

2019 ◽  
Author(s):  
Jiajun Wang ◽  
Meng-Yin Li ◽  
Jie Yang ◽  
Ya-Qian Wang ◽  
Xue-Yuan Wu ◽  
...  
Keyword(s):  
Dna Sequencing ◽  
Single Molecule ◽  
Genetic Diseases ◽  
High Sensitivity ◽  
Dna Lesions ◽  
Lesion Detection ◽  
The Novel ◽  
Structural Variations ◽  
Dna Lesion ◽  
Base Lesion

DNA lesion such as metholcytosine(<sup>m</sup>C), 8-OXO-guanine(<sup>O</sup>G), inosine(I) <i>etc</i> could cause the genetic diseases. Identification of the varieties of lesion bases are usually beyond the capability of conventional DNA sequencing which is mainly designed to discriminate four bases only. Therefore, lesion detection remain challenge due to the massive varieties and less distinguishable readouts for minor structural variations. Moreover, standard amplification and labelling hardly works in DNA lesions detection. Herein, we designed a single molecule interface from the mutant K238Q Aerolysin, whose confined sensing region shows the high compatible to capture and then directly convert each base lesion into distinguishable current readouts. Compared with previous single molecule sensing interface, the resolution of the K238Q Aerolysin nanopore is enhanced by 2-order. The novel K238Q could direct discriminate at least 3 types (<sup>m</sup>C, <sup>O</sup>G, I) lesions without lableing and quantify modification sites under mixed hetero-composition condition of oligonucleotide. Such nanopore could be further applied to diagnose genetic diseases at high sensitivity.

Sign in / Sign up

Export Citation Format

Share Document