Compact, infinite input resistance, wide receiving range, high-to-low voltage receiver circuits based on novel one-DMOS-FET linear level-shifting

2011 ◽  
Author(s):  
Yipin Zhang ◽  
Joachim N. Burghartz
Keyword(s):  
Low Voltage ◽  
Input Resistance

Biophysical Characterization of Rat Caudal Hypothalamic Neurons: Calcium Channel Contribution to Excitability

2000 ◽  
Vol 84 (6) ◽  
pp. 2896-2903 ◽  
Author(s):  
Yi-Ping Fan ◽  
Eric M. Horn ◽  
Tony G. Waldrop
Keyword(s):  
Membrane Potential ◽  
Low Voltage ◽  
Input Resistance ◽  
Calcium Currents ◽  
Resting Membrane Potential ◽  
Calcium Dependent ◽  
Rhythmic Firing ◽  
Almost All

Neurons in the caudal hypothalamus (CH) are responsible for the modulation of various processes including respiratory and cardiovascular output. Previous results from this and other laboratories have demonstrated in vivo that these neurons have firing rhythms matched to the respiratory and cardiovascular cycles. The goal of the present study was to characterize the biophysical properties of neurons in the CH with particular emphasis in those properties responsible for rhythmic firing behavior. Whole cell, patch-clamped CH neurons displayed a resting membrane potential of −58.0 ± 1.1 mV and an input resistance of 319.3 ± 16.6 MΩ when recorded in current-clamp mode in an in vitro brain slice preparation. A large proportion of these neurons displayed postinhibitory rebound (PIR) that was dependent on the duration and magnitude of hyperpolarizing current as well as the resting membrane potential of the cell. Furthermore these neurons discharged tonically in response to a depolarizing current pulse at a depolarized resting membrane potential (more positive than −65 mV) but switched to a rapid burst of firing to the same stimulus when the resting membrane potential was lowered. The PIR observed in these neurons was calcium dependent as demonstrated by the ability to block its amplitude by perfusion of Ca2+-free bath solution or by application of Ni2+ (0.3–0.5 mM) or nifedipine (10 μM). These properties suggest that low-voltage-activated (LVA) calcium current is involved in the PIR and bursting firing of these CH neurons. In addition, high-voltage-activated calcium responses were detected after blockade of outward potassium current or in Ba2+-replacement solution. In addition, almost all of the CH neurons studied showed spike frequency adaptation that was decreased following Ca2+ removal, indicating the involvement of Ca2+-dependent K+ current ( I K,Ca) in these cells. In conclusion, CH neurons have at least two different types of calcium currents that contribute to their excitability; the dominant current is the LVA or T-type. This LVA current appears to play a significant role in the bursting characteristics that may underlie the rhythmic firing of CH neurons.

scholarly journals High-Linearity Self-Biased CMOS Current Buffer

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 423
Author(s):  
Javier Martínez-Nieto ◽  
María Sanz-Pascual ◽  
Nicolás Medrano-Marqués ◽  
Belén Calvo-López ◽  
Arturo Sarmiento-Reyes
Keyword(s):  
High Performance ◽  
Simple Structure ◽  
Low Voltage ◽  
Harmonic Distortion ◽  
Input Resistance ◽  
Cmos Process ◽  
Output Current ◽  
Current Ratio ◽  
Class Ab ◽  
Static Power

A highly linear fully self-biased class AB current buffer designed in a standard 0.18 μ m CMOS process with 1.8 V power supply is presented in this paper. It is a simple structure that, with a static power consumption of 48 μ W, features an input resistance as low as 89 Ω , high accuracy in the input–output current ratio and total harmonic distortion (THD) figures lower than −60 dB at 30 μ A amplitude signal and 1 kHz frequency. Robustness was proved through Monte Carlo and corner simulations, and finally validated through experimental measurements, showing that the proposed configuration is a suitable choice for high performance low voltage low power applications.

scholarly journals Development of K+ and Na+ conductances in rodent postnatal semicircular canal type I hair cells

2010 ◽  
Vol 298 (2) ◽  
pp. R351-R358 ◽  
Author(s):  
Gang Q. Li ◽  
Frances L. Meredith ◽  
Katherine J. Rennie
Keyword(s):  
Hair Cells ◽  
Low Voltage ◽  
Semicircular Canals ◽  
Input Resistance ◽  
Membrane Properties ◽  
Delayed Rectifier ◽  
Type I ◽  
Adult Type ◽  
Whole Cell Patch Clamp ◽  
Ionic Changes

The rodent vestibular system is immature at birth. During the first postnatal week, vestibular type I and type II hair cells start to acquire their characteristic morphology and afferent innervation. We have studied postnatal changes in the membrane properties of type I hair cells acutely isolated from the semicircular canals (SCC) of gerbils and rats using whole cell patch clamp and report for the first time developmental changes in ionic conductances in these cells. At postnatal day (P) 5 immature hair cells expressed a delayed rectifier K+ conductance ( GDR) which activated at potentials above approximately −50 mV in both species. Hair cells also expressed a transient Na+ conductance ( GNa) with a mean half-inactivation of approximately −90 mV. At P6 in rat and P7 in gerbil, a low-voltage activated K+ conductance ( GK,L) was first observed and conferred a low-input resistance, typical of adult type I hair cells, on SCC type I hair cells. GK,L expression in hair cells increased markedly during the second postnatal week and was present in all rat type I hair cells by P14. In gerbil hair cells, GK,L appeared later and was present in all type I hair cells by P19. During the third postnatal week, GNa expression declined and was absent by the fourth postnatal week in rat and the sixth postnatal week in gerbils. Understanding the ionic changes associated with hair cell maturation could help elucidate development and regeneration mechanisms in the inner ear.

Processing of human melanoma cells for correlative TEM, LVSEM, and LM

1991 ◽  
Vol 49 ◽  
pp. 106-107
Author(s):  
Marek Malecki ◽  
J. Victor Small ◽  
James Pawley
Keyword(s):  
Electron Microscopy ◽  
Low Voltage ◽  
Fluorescent Microscopy ◽  
Blood Stream ◽  
Surface Topology ◽  
Integrin Receptors ◽  
Transmission Electron ◽  
Develop Technology ◽  
Voltage Scanning ◽  
Mechanisms Of Adhesion

The relative roles of adhesion and locomotion in malignancy have yet to be clearly established. In a tumor, subpopulations of cells may be recognized according to their capacity to invade neighbouring tissue,or to enter the blood stream and metastasize. The mechanisms of adhesion and locomotion are themselves tightly linked to the cytoskeletal apparatus and cell surface topology, including expression of integrin receptors. In our studies on melanomas with Fluorescent Microscopy (FM) and Cell Sorter(FACS), we noticed that cells in cultures derived from metastases had more numerous actin bundles, then cells from primary foci. Following this track, we attempted to develop technology allowing to compare ultrastructure of these cells using correlative Transmission Electron Microscopy(TEM) and Low Voltage Scanning Electron Microscopy(LVSEM).

High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

1991 ◽  
Vol 49 ◽  
pp. 64-65
Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Low Voltage ◽  
Culture Media ◽  
Cell Structure ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Culture Media ◽  
Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

Development of a conical anode Fe-gun for low voltage SEM

1988 ◽  
Vol 46 ◽  
pp. 978-979
Author(s):  
T. Miyokawa ◽  
S. Norioka ◽  
S. Goto
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Low Voltage ◽  
Irradiation Damage ◽  
Cold Cathode ◽  
Virtual Source ◽  
Source Position ◽  
Electrostatic Lens ◽  
Electrostatic Lenses ◽  
Wide Range

Field emission SEMs (FE-SEMs) are becoming popular due to their high resolution needs. In the field of semiconductor product, it is demanded to use the low accelerating voltage FE-SEM to avoid the electron irradiation damage and the electron charging up on samples. However the accelerating voltage of usual SEM with FE-gun is limited until 1 kV, which is not enough small for the present demands, because the virtual source goes far from the tip in lower accelerating voltages. This virtual source position depends on the shape of the electrostatic lens. So, we investigated several types of electrostatic lenses to be applicable to the lower accelerating voltage. In the result, it is found a field emission gun with a conical anode is effectively applied for a wide range of low accelerating voltages.A field emission gun usually consists of a field emission tip (cold cathode) and the Butler type electrostatic lens.

SEM analysis of DC magnetron sputtered beryllium films

1988 ◽  
Vol 46 ◽  
pp. 960-961
Author(s):  
E. F. Lindsey ◽  
C. W. Price ◽  
E. L. Pierce ◽  
E. J. Hsieh
Keyword(s):  
Fine Structure ◽  
Electron Emission ◽  
Secondary Electron ◽  
Low Voltage ◽  
Ion Beam ◽  
Secondary Electron Emission ◽  
Sem Analysis ◽  
Fused Silica ◽  
Grain Structure ◽  
Silica Substrate

Columnar structures produced by DC magnetron sputtering can be altered by using RF biased sputtering or by exposing the film to nitrogen pulses during sputtering, and these techniques are being evaluated to refine the grain structure in sputtered beryllium films deposited on fused silica substrates. Beryllium is brittle, and fractures in sputtered beryllium films tend to be intergranular; therefore, a convenient technique to analyze grain structure in these films is to fracture the coated specimens and examine them in an SEM. However, fine structure in sputtered deposits is difficult to image in an SEM, and both the low density and the low secondary electron emission coefficient of beryllium seriously compound this problem. Secondary electron emission can be improved by coating beryllium with Au or Au-Pd, and coating also was required to overcome severe charging of the fused silica substrate even at low voltage. The coating structure can obliterate much of the fine structure in beryllium films, but reasonable results were obtained by using the high-resolution capability of an Hitachi S-800 SEM and either ion-beam coating with Au-Pd or carbon coating by thermal evaporation.

Toward High-Resolution Low-Voltage SEM

1988 ◽  
Vol 46 ◽  
pp. 218-219
Author(s):  
Zhifeng Shao
Keyword(s):  
Low Voltage ◽  
Spherical Aberration ◽  
Chromatic Aberration ◽  
Limiting Factor ◽  
Operating Voltage ◽  
Probe Radius ◽  
Non Local ◽  
Electron Microscopes ◽  
Image Position ◽  
Scanning Electron Microscopes

Recently, low voltage (≤5kV) scanning electron microscopes have become popular because of their unprecedented advantages, such as minimized charging effects and smaller specimen damage, etc. Perhaps the most important advantage of LVSEM is that they may be able to provide ultrahigh resolution since the interaction volume decreases when electron energy is reduced. It is obvious that no matter how low the operating voltage is, the resolution is always poorer than the probe radius. To achieve 10Å resolution at 5kV (including non-local effects), we would require a probe radius of 5∽6 Å. At low voltages, we can no longer ignore the effects of chromatic aberration because of the increased ratio δV/V. The 3rd order spherical aberration is another major limiting factor. The optimized aperture should be calculated as

High-Resolution, Low-Voltage SEM of Cell Wall Regeneration of Yeast Shizosaccharomyces Pombe Protoplasts

1988 ◽  
Vol 46 ◽  
pp. 208-211
Author(s):  
M. Osumi ◽  
N. Yamada ◽  
T. Nagatani
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Low Voltage ◽  
Cell Wall Regeneration ◽  
The Past ◽  
The Poor ◽  
Probe Size ◽  
Beam Damage ◽  
Biological Field ◽  
Scanning Electron

Even though many early workers had suggested the use of lower voltages to increase topographic contrast and to reduce specimen charging and beam damage, we did not usually operate in the conventional scanning electron microscope at low voltage because of the poor resolution, especially of bioligical specimens. However, the development of the “in-lens” field emission scanning electron microscope (FESEM) has led to marked inprovement in resolution, especially in the range of 1-5 kV, within the past year. The probe size has been cumulated to be 0.7nm in diameter at 30kV and about 3nm at 1kV. We have been trying to develop techniques to use this in-lens FESEM at low voltage (LVSEM) for direct observation of totally uncoated biological specimens and have developed the LVSEM method for the biological field.

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