scholarly journals Isolation of a neuropeptide from locust corpus cardiacum which influences ileal transport.

1992 ◽  
Vol 173 (1) ◽  
pp. 261-274 ◽  
Author(s):  
N Audsley ◽  
C McIntosh ◽  
J E Phillips
Keyword(s):  
High Performance ◽  
Schistocerca Gregaria ◽  
Short Circuit ◽  
Carcinus Maenas ◽  
Short Circuit Current ◽  
Homarus Americanus ◽  
Shore Crab ◽  
Relative Molecular Mass ◽  
Corpus Cardiacum ◽  
Orconectes Limosus

1. Schistocerca gregaria ion-transport peptide (Scg-ITP) was isolated from aqueous extracts of the corpus cardiacum by a four-step procedure, utilizing reverse-phase high-performance liquid chromatography for separation and stimulation of a Cl(-)-dependent short-circuit current (Isc) across locust ilea as the bioassay. 2. Scg-ITP has an unblocked N terminus and an apparent relative molecular mass of 7700. Thirty-one residues (of an estimated 65) were identified by sequence analysis. 3. Scg-ITP is structurally related to a crustacean family of neuropeptides which includes the crustacean hyperglycaemic hormones from the shore crab Carcinus maenas and the crayfish Orconectes limosus and moult-inhibiting hormone and vitellogenesis-inhibiting hormone from the lobster Homarus americanus. 4. Scg-ITP has no sequence homology with neuroparsins (Nps). Nps are the only other neuropeptides isolated to date that might regulate reabsorption in an insect hindgut (rectum).

Active ammonia excretion across the gills of the green shore crabCarcinus maenas: participation of Na+/K+-ATPase, V-type H+-ATPase and functional microtubules

2002 ◽  
Vol 205 (18) ◽  
pp. 2765-2775 ◽  
Author(s):  
Dirk Weihrauch ◽  
Andreas Ziegler ◽  
Dietrich Siebers ◽  
David W. Towle
Keyword(s):  
Short Circuit ◽  
Basolateral Membrane ◽  
Carcinus Maenas ◽  
Specific Inhibitor ◽  
Ammonia Excretion ◽  
Short Circuit Current ◽  
Shore Crab ◽  
Dependent Manner ◽  
Microtubule Network ◽  
Experimental Conditions

SUMMARYAlthough aquatic animals are generally believed to export nitrogenous waste by diffusion of NH3 or NH4+ across external epithelia, evidence for active ammonia excretion has been found in a number of species. In the euryhaline green shore crab Carcinus maenas, active excretion of ammonia across isolated gills is reduced by inhibitors of the Na+/K+-ATPase and vacuolar-type H+-ATPase. In addition, a functional dynamic microtubule network is necessary, since application of colchicine, taxol or thiabendazole leads to almost complete blockage of active and gradient-driven ammonia excretion. Actin filaments seem not to play a role in the excretory process. The NH4+-dependent short-circuit current and the conductance of the isolated cuticle were reduced in a dose-dependent manner by amiloride,a non-specific inhibitor of the Na+/H+ exchanger and Na+ channels. Combined with an analysis of gill morphology, the strong intracellular but weak apical abundance of V-type H+-ATPase and the fact that ammonia flux rates are equal under buffered and unbuffered experimental conditions, our observations suggest a hypothetical model of transepithelial ammonia movement that features active uptake across the basolateral membrane, sequestration in acidified vesicles, vesicle transport via microtubules and exocytosis at the apical membrane.

Ion transport across posterior gills of hyperosmoregulating shore crabs (Carcinus maenas): amiloride blocks the cuticular Na+ conductance and induces current-noise

2002 ◽  
Vol 205 (4) ◽  
pp. 523-531 ◽  
Author(s):  
Horst Onken ◽  
Sven Riestenpatt
Keyword(s):  
Short Circuit ◽  
Noise Analysis ◽  
Carcinus Maenas ◽  
Low Frequency ◽  
Short Circuit Current ◽  
Current Noise ◽  
Corner Frequency ◽  
Shore Crab ◽  
Shore Crabs ◽  
Gill Lamellae

SUMMARYSplit gill lamellae and gill cuticles of shore crabs (Carcinus maenas) adapted to 10 ‰ salinity were mounted in a modified Ussing-type chamber. With NaCl saline on both sides, split gill lamellae generated a short-circuit current (Isc) of –301±16 μA cm–2 at a conductance (Gte) of 40±2 mS cm–2. The net influxes of Na+ and Cl– were 8.3±2.6 and 18.2±2.7 μmol cm–2 h–1, respectively. External amiloride (100 μmol l–1) reduced Gte to approximately 50 % of the original value at unchanged Isc; Cl– fluxes remained unaffected, whereas Na+ fluxes were markedly reduced by 70–80 %. The Isc in the presence of external amiloride was almost completely inhibited by internal ouabain. At a clamp voltage of 50 mV (outside-positive), a positive current was measured at unchanged Gte. Under these conditions, amiloride reduced the current and conductance at half-maximal concentrations of 3.6 and 2.0 μmol l–1, respectively. At outside-positive voltages, but not under short-circuit conditions, external amiloride induced Lorentzian components in the power density spectra. The amiloride-dependent changes in the corner frequency (linear) and of the low-frequency plateau (‘bell-shaped’) were as expected for channel blockade by amiloride with pseudo-first-order kinetics. With an outside-positive clamp voltage of 50 mV across isolated cuticles, a positive cuticular current (Icut) of 25 188±3791 μA cm–2 and a cuticular conductance (Gcut) of 547±76 mS cm–2 were measured. External amiloride reduced Icut and Gcut at half-maximal concentrations of 0.7 and 0.6 μmol l–1, respectively. Amiloride-induced current-noise analysis gave similar results to those observed with split gill lamellae. Ion-substitution experiments with isolated cuticles further support inhibition by external amiloride of the cuticular Na+ conductance of shore crab gills and not amiloride-sensitive transporters (Na+ channels or Na+/H+ antiports) in the apical membrane.

Active absorption of Na+ and Cl- across the gill epithelium of the shore crab Carcinus maenas: voltage-clamp and ion-flux studies

1996 ◽  
Vol 199 (7) ◽  
pp. 1545-1554 ◽  
Author(s):  
S Riestenpatt ◽  
H Onken ◽  
D Siebers
Keyword(s):  
Short Circuit ◽  
Ussing Chamber ◽  
Basolateral Membrane ◽  
Carcinus Maenas ◽  
Short Circuit Current ◽  
Shore Crab ◽  
Thick Ascending Limb ◽  
Gill Epithelium ◽  
Apical Side ◽  
Shore Crabs

Mechanisms of active NaCl uptake across the posterior gills of the shore crab Carcinus maenas were examined using radiochemical and electrophysiological techniques. In order to measure short-circuit current (Isc), transepithelial conductance (Gte) and area-related unidirectional fluxes of Na+ and Cl-, single split gill lamellae (epithelium plus cuticle) of hyperregulating shore crabs were mounted in a modified Ussing chamber. The negative short-circuit current measured with haemolymph-like NaCl saline on both sides of the epithelium could be inhibited by application of basolateral ouabain (ouabain inhibitor constant KOua=56±10 µmol l-1), 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB; KNPPB=7.5±2.5 mmol l-1) or Cs+ (10 mmol l-1). From the apical side, Isc was nearly completely blocked by Cs+ (10 mmol l-1) or Ba2+ (15 µmol l-1), whereas apical addition of furosemide (1 mmol l-1) resulted in only a small current decrease. Cl- influxes were linearly related to negative Isc. The ratio between net influxes of Cl- and Na+ was found to be approximately 2:1. With a single membrane preparation, achieved by permeabilizing the basolateral membrane with amphotericin B, Cl- influxes which were driven by a concentration gradient were shown to depend on the presence of apical Na+ and K+. On the basis of these observations, we propose that active and electrogenic absorption of NaCl across the gill epithelium of hyperregulating shore crabs proceeds as in the thick ascending limb of Henle's loop in the mammalian nephron. Accordingly, branchial NaCl transport is mediated by apical K+ channels in cooperation with apical Na+/K+/2Cl- cotransporters and by the basolateral Na+/K+-ATPase and basolateral Cl- channels.

scholarly journals Antireflection Improvement and Junction Quality Optimization of Si/PEDOT:PSS Solar Cell with the Introduction of Dopamine@Graphene

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5986
Author(s):  
Tao Chen ◽  
Hao Guo ◽  
Leiming Yu ◽  
Tao Sun ◽  
Anran Chen ◽  
...  
Keyword(s):  
Solar Cell ◽  
Conversion Efficiency ◽  
High Performance ◽  
Electrochemical Impedance ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Electrochemical Impedance Spectra ◽  
Solar Cell Performance ◽  
Photovoltaic Conversion ◽  
Photovoltaic Conversion Efficiency

Si/PEDOT: PSS solar cell is an optional photovoltaic device owing to its promising high photovoltaic conversion efficiency (PCE) and economic manufacture process. In this work, dopamine@graphene was firstly introduced between the silicon substrate and PEDOT:PSS film for Si/PEDOT: PSS solar cell. The dopamine@graphene was proved to be effective in improving the PCE, and the influence of mechanical properties of dopamine@graphene on solar cell performance was revealed. When dopamine@graphene was incorporated into the cell preparation, the antireflection ability of the cell was enhanced within the wavelength range of 300~450 and 650~1100 nm. The enhanced antireflection ability would benefit amount of the photon-generated carriers. The electrochemical impedance spectra test revealed that the introduction of dopamine@graphene could facilitate the separation of carriers and improve the junction quality. Thus, the short-circuit current density and fill factor were both promoted, which led to the improved PCE. Meanwhile, the influence of graphene concentration on device performances was also investigated. The photovoltaic conversion efficiency would be promoted from 11.06% to 13.15% when dopamine@graphene solution with concentration 1.5 mg/mL was applied. The achievements of this study showed that the dopamine@graphene composites could be an useful materials for high-performance Si/PEDOT:PSS solar cells.

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

2019 ◽  
Vol 12 (1) ◽  
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.

scholarly journals Silicon Substrate Treated with Diluted NaOH Aqueous for Si/PEDOT: PSS Heterojunction Solar Cell with Performance Enhancement

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4659
Author(s):  
Tao Chen ◽  
Hao Guo ◽  
Leiming Yu ◽  
Tao Sun ◽  
Yu Yang
Keyword(s):  
Aqueous Solution ◽  
Solar Cell ◽  
Silicon Substrate ◽  
High Performance ◽  
Immersion Time ◽  
Performance Enhancement ◽  
Light Trapping ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density

Si/PEDOT: PSS solar cell is an important alternative for photovoltaic device due to its anticipated high theoretical efficiency and simple manufacturing process. In this study, processing silicon substrate with diluted NaOH aqueous solution was found to be an effective method for improving device performance, one that notably improves junction quality and light trapping ability. When immersed in diluted NaOH aqueous solution, the junction quality was improved according to the enlarged fill factor, reduced series resistance, and enhanced minor carrier lifetime. The diluted NaOH aqueous solution immersion etched the silicon surface and helped with the enhancement of light trapping ability, further improving the short-circuit current density. Although diluted NaOH aqueous solution immersion for bare silicon could improve the performance of devices, proper immersion time was needed. The influence of immersion time on device performances was investigated. The photovoltaic conversion efficiency easily increased from 10.01% to 12.05% when silicon substrate was immersed in diluted NaOH aqueous for 15 min. This study contributes to providing efficient and convenient methods for preparing high performance Si/PEDOT: PSS solar cells.

scholarly journals With PBDB-T as the Donor, the PCE of Non-Fullerene Organic Solar Cells Based on Small Molecule INTIC Increased by 52.4%

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1324 ◽  
Author(s):  
Weifang Zhang ◽  
Zicha Li ◽  
Suling Zhao ◽  
Zheng Xu ◽  
Bo Qiao ◽  
...  
Keyword(s):  
Solar Cells ◽  
Small Molecule ◽  
Organic Solar Cells ◽  
High Performance ◽  
Short Circuit ◽  
Photovoltaic Performance ◽  
Short Circuit Current ◽  
Production Costs ◽  
Higher Carrier Mobility ◽  
Carrier Transportation

At present, most high-performance non-fullerene materials are centered on fused rings. With the increase in the number of fused rings, production costs and production difficulties increase. Compared with other non-fullerenes, small molecule INTIC has the advantages of easy synthesis and strong and wide infrared absorption. According to our previous report, the maximum power conversion efficiency (PCE) of an organic solar cell using PTB7-Th:INTIC as the active layer was 7.27%. In this work, other polymers, PTB7, PBDB-T and PBDB-T-2F, as the donor materials, with INTIC as the acceptor, are selected to fabricate cells with the same structure to optimize their photovoltaic performance. The experimental results show that the optimal PCE of PBDB-T:INTIC based organic solar cells is 11.08%, which, thanks to the open voltage (VOC) increases from 0.80 V to 0.84 V, the short circuit current (JSC) increases from 15.32 mA/cm2 to 19.42 mA/cm2 and the fill factor (FF) increases from 60.08% to 67.89%, then a 52.4% improvement in PCE is the result, compared with the devices based on PTB7-Th:INTIC. This is because the PBDB-T:INTIC system has better carrier dissociation and extraction, carrier transportation and higher carrier mobility.

A naphthodithiophene-based nonfullerene acceptor for high-performance polymer solar cells with a small energy loss

2020 ◽  
Vol 8 (19) ◽  
pp. 6513-6520 ◽  
Author(s):  
Xingliang Dong ◽  
Qing Guo ◽  
Qi Liu ◽  
Lei Zhu ◽  
Xia Guo ◽  
...  
Keyword(s):  
High Performance ◽  
Open Circuit Voltage ◽  
Polymer Solar Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Small Energy ◽  
High Performance Polymer ◽  
Nonfullerene Acceptor

A new non-fullerene acceptor named NTO-4F is developed. The optimal PSC based on PM6:NTO-4F achieves a PCE of 11.5% with simultaneously high open-circuit voltage of 0.99 V and short-circuit current density of 19.1 mA cm−2.

Na+-K+-ATPase and Na+/Ca2+exchange activities in gills of hyperregulatingCarcinus maenas

1999 ◽  
Vol 276 (2) ◽  
pp. R490-R499 ◽  
Author(s):  
Čedomil Lucu ◽  
Gert Flik
Keyword(s):  
Atpase Activity ◽  
Specific Activity ◽  
Short Circuit ◽  
Carcinus Maenas ◽  
High Capacity ◽  
Short Circuit Current ◽  
Total Activity ◽  
Camp Content ◽  
Dependent Protein ◽  
Leaky Epithelium

Na+-K+-ATPase and Na+/Ca2+exchange activities were studied in gills of Carcinus maenas in seawater (SW) and after transfer to dilute seawater (DSW). Carcinushyperregulates its hemolymph osmolarity through active uptake of Na+, Cl−, and Ca2+. In DSW total Na+-K+-ATPase activity in posterior gills quadrupled; Na+/Ca2+exchange specific activity was unaffected, and total activity increased 1.67-fold. Short-circuit current ( Isc) in voltage-clamped posterior gill hemilamellae was −181 μA/cm2in SW and −290 μA/cm2in DSW and up to 90% ouabain sensitive; conductivity was similar in SW or DSW (42 and 46 mS/cm2, respectively) and representative of a leaky epithelium. The new steady state of hemolymph osmolarity 24 h after DSW transfer was preceded, already 3 h after transfer, by increased Na+-K+-ATPase but not Na+/Ca2+exchange activity. Western blot analysis indicated that the amount of Na+-K+-ATPase protein had increased 2.1-fold in crabs acclimated 3 wk to DSW; however, 4 h after DSW transfer no difference in the amount of Na+-K+-ATPase protein was observed. After DSW transfer branchial cAMP content decreased. A negative correlation between branchial Na+-K+-ATPase activity and cAMP content points to rapid regulation of Na+-K+-ATPase through cAMP-dependent protein kinase A activity. Ca2+transport may depend on the high-capacity Na+/Ca2+exchanger coupled to the versatile sodium pump.

scholarly journals Electrodeposition Combination with Hydrothermal Preparation of ZnO Films and Their Application in Dye-Sensitized Solar Cell

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Xiaoping Zou ◽  
Yan Liu ◽  
Cuiliu Wei ◽  
Zongbo Huang ◽  
Xiangmin Meng
Keyword(s):  
High Performance ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Suitable Method ◽  
Second Step ◽  
Zno Films ◽  
Hydrothermal Preparation ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

A suitable method is necessary for the high performance of dyes-sensitized solar cells (DSSCs). In this paper, photoanodes of DSSCs have been fabricated through electrodeposition and combination with hydrothermal method. The results of mix method showed better performance than the single one. After the second step electrodeposition, the ZnO films formed flack finally. With the increase of hydrothermal time, ZnO films become thicker and bigger, which can offer large surface area to absorb much more dyes. The short-circuit current (2.4 mA/cm2) and open-circuit voltage (0.67 V) were greater than the single one, alternating current impedance indicating that electrodeposition and hydrothermal mix are a more suitable method for high performance DSSCs. We expected to obtain higher conversion efficiency of DSSCs by this method.

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