Segregation of gastric Na and Cl transport: a vibrating probe and microelectrode study

The short-circuit current (Isc) of resting Necturus gastric mucosa (approximately 20 microA/cm2) can be attributed to the algebraic sum of the net Cl- secretion and amiloride-inhibitable net Na+ absorption. We have attempted to identify the cell types [surface epithelial cells (SCs) or oxyntic cells (OCs)] responsible for the transport of these ions in Necturus gastric mucosa using microelectrodes (ME) and a vibrating probe (VP). Mucosae were mounted horizontally in an open-topped Plexiglas chamber either serosal side up for basolateral ME impalements of OCs or mucosal side up for apical impalements of SCs and VP measurements. Cell impalements were made under open-circuit conditions, and VP measurements were performed under short-circuit conditions. Impalements of OCs indicate that neither the ratio of their apical to basolateral cell membrane resistances (Ra/Rb = 1.3 +/- 0.2) nor their cell membrane potentials were affected by 10(-6) M mucosal amiloride. In contrast, impalements of SCs indicate that amiloride increased their Ra/Rb from 3.5 +/- 0.2 to 15.6 +/- 1.8 and hyperpolarized both cell membrane potentials by greater than 20 mV. VP measurements showed that the amiloride-induced change in the current from SCs (5.6 microA/cm2) accounted for the amiloride-induced change in the Isc (5.5 microA/cm2). A non-zero current (4.4 +/- 1.0 microA/cm2) measured over SCs in the presence of amiloride was due to contamination from current arising from the gastric crypts that contain the OCs.(ABSTRACT TRUNCATED AT 250 WORDS)

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Effects of biguanides on short-circuit current in frog skin

AJP Renal Physiology ◽

10.1152/ajprenal.1984.247.2.f277 ◽

1984 ◽

Vol 247 (2) ◽

pp. F277-F281

Author(s):

T. Saito ◽

S. Yoshida

Keyword(s):

Sodium Transport ◽

Frog Skin ◽

Short Circuit ◽

Short Circuit Current ◽

Open Circuit ◽

Apical Surface ◽

Sodium Permeability ◽

Total Conductance ◽

Mucosal Side ◽

Stimulation Of

The addition of phenformin to the solution bathing the mucosal side of frog skin resulted in a sustained stimulation of short-circuit current accompanied by an increase in open-circuit potential and total conductance of the membrane. The flux of 22Na from the mucosal to the serosal side of the skin was increased by phenformin, whereas no significant effect on the flux from the serosal to the mucosal side was observed. The increases in the short-circuit current and total conductance with phenformin were completely abolished by the addition of 5 X 10(-5) M amiloride, which blocks sodium permeability at the apical surface of the membrane. Thus, the stimulation of active sodium transport in frog skin by phenformin would be due to the increase in the amiloride-sensitive sodium permeability of the membrane. Phenformin may prove to be a useful tool for the study of sodium transport in amphibian epithelia.

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Mechanisms of active Cl- secretion by frog gastric mucosa

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1987.252.4.g543 ◽

1987 ◽

Vol 252 (4) ◽

pp. G543-G547 ◽

Cited By ~ 3

Author(s):

W. W. Reenstra ◽

J. D. Bettencourt ◽

J. G. Forte

Keyword(s):

Gastric Mucosa ◽

Acid Secretion ◽

Cation Exchange ◽

Short Circuit ◽

Short Circuit Current ◽

Open Circuit ◽

Potential Difference ◽

Cl Secretion ◽

Oxyntic Cell

Net Cl- flux across the bullfrog gastric mucosa was examined to test the hypothesis that Cl-secretion (JClnet) can be driven by either of the two cation exchange pumps in the oxyntic cell. The effects on JClnet of ouabain, an Na+-K+ pump inhibitor, and omeprazole, an H+-K+ pump inhibitor were examined. Omeprazole abolished acid secretion (JH) and reduced JClnet in bullfrog gastric mucosa. For mucosae at open circuit the omeprazole-induced decrease in JH was not significantly different than the decrease in JClnet, and the transmucosal potential difference (PD) was increased. When short-circuited mucosae were treated with omeprazole, the decrease in JClnet was significantly less than the decrease in JH, and short-circuit current (SCC) was correspondingly increased. After treatment of short-circuited mucosae with ouabain, the omeprazole-induced decreases in JH and JClnet were not significantly different, and no change in SCC occurred. For open-circuited mucosae, pretreatment with ouabain resulted in a significantly smaller omeprazole-induced increase in the transmucosal PD than was seen without ouabain pretreatment. Our data 1) show that both the H+-K+ pump and the Na+-K+ pump can drive Cl- secretion and 2) suggest that inhibition of the H+-K+ pump with omeprazole stimulates the Na+-K+ pump.

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Cl - transport by gastric mucosa: cellular Cl - activity and membrane permeability

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1982.0152 ◽

1982 ◽

Vol 299 (1097) ◽

pp. 559-573 ◽

Cited By ~ 10

Keyword(s):

Gastric Mucosa ◽

Chemical Potential ◽

Short Circuit ◽

Electrical Potential ◽

Short Circuit Current ◽

Open Circuit ◽

Constant Field ◽

Entry Rate ◽

S Uptake ◽

Tracer Experiments

The mechanism of Cl - secretion in the isolated, resting (i.e. cimetidine-treated) gastric mucosa of Necturus has been investigated with radioisotopic and electrophysiological techniques. Measurement of transepithelial 36 C1 - fluxes (mucosal to serosal (M→S), J Cl - ms ; S→M, J Cl - sm ) during control conditions show that at open circuit, when the transepithelial potential difference Ψ ms = 20 mV (S ground), J Cl - ms = J Cl - sm , i.e. J Cl - net = 0, but during short-circuit current conditions J Cl - net = I sc = 2 μ equiv cm -2 h. Experiments with low [Cl - ] solutions indicate that Cl - exchange diffusion does not contribute significantly to either J Cl - ms or J Cl - sm . Double-barrelled, Cl - -selective microelectrodes showed that in open circuit, the cellular (C) chemical potential for Cl - , Ψ Cl - e = 31 mV (apparent [Cl - ] = 29 mM), the electrical potential across the M membrane, Ψ m = — 34 mV (mucosa ground) while that across the S membrane, Ψ s = — 52 mV (serosa ground). During short-circuit current conditions, Ψ m = Ψ s = —49 mV and [Cl - ] e = 30 mM. The permeability of the M membrane to Cl - ( Ρ Cl - m ) was calculated both from the tracer experiments and the electrode measurements by using the constant-field equation. Short-term (45 s) uptake of 36 Cl - at [Cl - ] m = 96 mM during short circuit conditions gave Ρ Cl - m = 2.6 x 10 -5 cm s -1 . Measurement of [Cl - ] c by means of the electrodes when [Cl - ] m was changed from 96 to 2 mM or from 2 to 96 mM gave Ρ Cl - m = 2.9- 5.7 x 10 -5 cm s -1 . Our results indicate that during open circuit conditions Cl - is accumulated across the S membrane into gastric cells in an energy-requiring step, but since J Cl - net = 0, Cl - must leak back into the S solution at a rate equal to the entry rate. When the tissue is short-circuited, Cl - secretion occurs ( J Cl - net = I sc ) owing to the same energy-requiring accumulation of Cl - by the cells and a passive (apparently electrodiffusive) movement across the mucosal membrane.

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CdTe-Based Thin Film Solar Cells: Past, Present and Future

Energies ◽

10.3390/en14061684 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1684

Author(s):

Alessandro Romeo ◽

Elisa Artegiani

Keyword(s):

Thin Film ◽

Solar Cells ◽

Solar Cell ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Early Years ◽

Solar Cell Efficiency ◽

Cell Efficiency

CdTe is a very robust and chemically stable material and for this reason its related solar cell thin film photovoltaic technology is now the only thin film technology in the first 10 top producers in the world. CdTe has an optimum band gap for the Schockley-Queisser limit and could deliver very high efficiencies as single junction device of more than 32%, with an open circuit voltage of 1 V and a short circuit current density exceeding 30 mA/cm2. CdTe solar cells were introduced at the beginning of the 70s and they have been studied and implemented particularly in the last 30 years. The strong improvement in efficiency in the last 5 years was obtained by a new redesign of the CdTe solar cell device reaching a single solar cell efficiency of 22.1% and a module efficiency of 19%. In this paper we describe the fabrication process following the history of the solar cell as it was developed in the early years up to the latest development and changes. Moreover the paper also presents future possible alternative absorbers and discusses the only apparently controversial environmental impacts of this fantastic technology.

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GaInP/GaAs/poly-Si Multi-Junction Solar Cells by in Metal Balls Bonding

Crystals ◽

10.3390/cryst11070726 ◽

2021 ◽

Vol 11 (7) ◽

pp. 726

Author(s):

Ray-Hua Horng ◽

Yu-Cheng Kao ◽

Apoorva Sood ◽

Po-Liang Liu ◽

Wei-Cheng Wang ◽

...

Keyword(s):

Solar Cells ◽

Solar Cell ◽

Low Temperature ◽

Triple Junction ◽

Short Circuit ◽

Short Circuit Current ◽

Open Circuit ◽

Metal Line ◽

Solar Simulator ◽

Junction Solar Cell

In this study, a mechanical stacking technique has been used to bond together the GaInP/GaAs and poly-silicon (Si) solar wafers. A GaInP/GaAs/poly-Si triple-junction solar cell has mechanically stacked using a low-temperature bonding process which involves micro metal In balls on a metal line using a high-optical-transmission spin-coated glue material. Current–voltage measurements of the GaInP/GaAs/poly-Si triple-junction solar cells have carried out at room temperature both in the dark and under 1 sun with 100 mW/cm2 power density using a solar simulator. The GaInP/GaAs/poly-Si triple-junction solar cell has reached an efficiency of 24.5% with an open-circuit voltage of 2.68 V, a short-circuit current density of 12.39 mA/cm2, and a fill-factor of 73.8%. This study demonstrates a great potential for the low-temperature micro-metal-ball mechanical stacking technique to achieve high conversion efficiency for solar cells with three or more junctions.

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Photocurrent density and electrical properties of Bi0.5Na0.5TiO3-BaNi0.5Nb0.5O3 ceramics

Journal of Advanced Ceramics ◽

10.1007/s40145-021-0497-7 ◽

2021 ◽

Author(s):

Mingqiang Zhong ◽

Qin Feng ◽

Changlai Yuan ◽

Xiao Liu ◽

Baohua Zhu ◽

...

Keyword(s):

Electrical Properties ◽

Photovoltaic Effect ◽

Short Circuit ◽

Short Circuit Current ◽

Photocurrent Density ◽

Open Circuit ◽

Light Conditions ◽

X Ray Diffraction ◽

Solid State Method ◽

X Ray

AbstractIn this work, the (1−x)Bi0.5Na0.5TiO3-xBaNi0.5Nb0.5O3 (BNT-BNN; 0.00 ⩽ x ⩽ 0.20) ceramics were prepared via a high-temperature solid-state method. The crystalline structures, photovoltaic effect, and electrical properties of the ceramics were investigated. According to X-ray diffraction, the system shows a single perovskite structure. The samples show the normal ferroelectric loops. With the increase of BNN content, the remnant polarization (Pr) and coercive field (Ec) decrease gradually. The optical band gap of the samples narrows from 3.10 to 2.27 eV. The conductive species of grains and grain boundaries in the ceramics are ascribed to the double ionized oxygen vacancies. The open-circuit voltage (Voc) of ∼15.7 V and short-circuit current (Jsc) of ∼1450 nA/cm2 are obtained in the 0.95BNT-0.05BNN ceramic under 1 sun illumination (AM1.5G, 100 mW/cm2). A larger Voc of 23 V and a higher Jsc of 5500 nA/cm2 are achieved at the poling field of 60 kV/cm under the same light conditions. The study shows this system has great application prospects in the photovoltaic field.

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Ultrathin Cu(In,Ga)Se2 Solar Cells with Ag/AlOx Passivating Back Reflector

Energies ◽

10.3390/en14144268 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4268

Author(s):

Jessica de Wild ◽

Gizem Birant ◽

Guy Brammertz ◽

Marc Meuris ◽

Jef Poortmans ◽

...

Keyword(s):

Surface Roughness ◽

Solar Cells ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Electron Microscopic ◽

Current Increase ◽

Time Resolved ◽

Cigs Solar Cells

Ultrathin Cu(In,Ga)Se2 (CIGS) absorber layers of 550 nm were grown on Ag/AlOx stacks. The addition of the stack resulted in solar cells with improved fill factor, open circuit voltage and short circuit current density. The efficiency was increased from 7% to almost 12%. Photoluminescence (PL) and time resolved PL were improved, which was attributed to the passivating properties of AlOx. A current increase of almost 2 mA/cm2 was measured, due to increased light scattering and surface roughness. With time of flight—secondary ion mass spectroscopy, the elemental profiles were measured. It was found that the Ag is incorporated through the whole CIGS layer. Secondary electron microscopic images of the Mo back revealed residuals of the Ag/AlOx stack, which was confirmed by energy dispersive X-ray spectroscopy measurements. It is assumed to induce the increased surface roughness and scattering properties. At the front, large stains are visible for the cells with the Ag/AlOx back contact. An ammonia sulfide etching step was therefore applied on the bare absorber improving the efficiency further to 11.7%. It shows the potential of utilizing an Ag/AlOx stack at the back to improve both electrical and optical properties of ultrathin CIGS solar cells.

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Enhancement of the performance of CdS/CdTe heterojunction solar cell using TiO2/ZnO bi-layer ARC and V2O5 BSF layers: A simulation approach

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020200213 ◽

2020 ◽

Vol 92 (2) ◽

pp. 20901

Author(s):

Abdul Kuddus ◽

Md. Ferdous Rahman ◽

Jaker Hossain ◽

Abu Bakar Md. Ismail

Keyword(s):

Solar Cell ◽

Short Circuit ◽

Photovoltaic Performance ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Heterojunction Solar Cell ◽

Back Surface ◽

Heterojunction Solar Cells

This article presents the role of Bi-layer anti-reflection coating (ARC) of TiO2/ZnO and back surface field (BSF) of V2O5 for improving the photovoltaic performance of Cadmium Sulfide (CdS) and Cadmium Telluride (CdTe) based heterojunction solar cells (HJSCs). The simulation was performed at different concentrations, thickness, defect densities of each active materials and working temperatures to optimize the most excellent structure and working conditions for achieving the highest cell performance using obtained optical and electrical parameters value from the experimental investigation on spin-coated CdS, CdTe, ZnO, TiO2 and V2O5 thin films deposited on the glass substrate. The simulation results reveal that the designed CdS/CdTe based heterojunction cell offers the highest efficiency, η of ∼25% with an enhanced open-circuit voltage, Voc of 0.811 V, short circuit current density, Jsc of 38.51 mA cm−2, fill factor, FF of 80% with bi-layer ARC and BSF. Moreover, it appears that the TiO2/ZnO bi-layer ARC, as well as ETL and V2O5 as BSF, could be highly promising materials of choice for CdS/CdTe based heterojunction solar cell.

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Online current-sensorless estimator for PV open circuit voltage and short circuit current

Solar Energy ◽

10.1016/j.solener.2020.11.004 ◽

2021 ◽

Vol 213 ◽

pp. 198-210

Author(s):

Ahsan Nadeem ◽

Hadeed Ahmed Sher ◽

Ali Faisal Murtaza ◽

Nisar Ahmed

Keyword(s):

Open Circuit Voltage ◽

Short Circuit ◽

Short Circuit Current ◽

Open Circuit ◽

Current Sensorless

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A Self-Powered Nanogenerator for the Electrical Protection of Integrated Circuits from Trace Amounts of Liquid

Nano-Micro Letters ◽

10.1007/s40820-019-0338-1 ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 3

Author(s):

Zhuang Hui ◽

Ming Xiao ◽

Daozhi Shen ◽

Jiayun Feng ◽

Peng Peng ◽

...

Keyword(s):

Integrated Circuits ◽

High Performance ◽

Printed Circuit Board ◽

Short Circuit ◽

High Sensitivity ◽

Short Circuit Current ◽

Fast Response ◽

Open Circuit ◽

Circuit Board ◽

Self Powered

Abstract With the increase in the use of electronic devices in many different environments, a need has arisen for an easily implemented method for the rapid, sensitive detection of liquids in the vicinity of electronic components. In this work, a high-performance power generator that combines carbon nanoparticles and TiO2 nanowires has been fabricated by sequential electrophoretic deposition (EPD). The open-circuit voltage and short-circuit current of a single generator are found to exceed 0.7 V and 100 μA when 6 μL of water was applied. The generator is also found to have a stable and reproducible response to other liquids. An output voltage of 0.3 V was obtained after 244, 876, 931, and 184 μs, on exposure of the generator to 6 μL of water, ethanol, acetone, and methanol, respectively. The fast response time and high sensitivity to liquids show that the device has great potential for the detection of small quantities of liquid. In addition, the simple easily implemented sequential EPD method ensures the high mechanical strength of the device. This compact, reliable device provides a new method for the sensitive, rapid detection of extraneous liquids before they can impact the performance of electronic circuits, particularly those on printed circuit board.

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