scholarly journals A mechanism underlying hERG current increase by a blocker

Author(s):  
Kazuharu Furutani ◽  
Steffen Docken ◽  
Igor Vorobyov ◽  
Colleen Clancy ◽  
Timothy Lewis ◽  
...  
Author(s):  
Dr.Seethal Peenikkal ◽  
Dr.K.Savitha R. Shenoy ◽  
Dr.Sri Nagesh K.A.

Breast Cancer is one of the most common types of malignancy among Indian woman currently. The current increase in the world wide prevalence of this disease suggests an urgent need of detailed analysis, diagnosis and treatment line through Ayurvedic principles. As cancer is least understood in technical terms of Ayurveda, Nidana Panchaka a basic tool to understand and diagnose a Vyadhi, is used to analyze it. Even though a direct diagnostic correlation of breast cancer is not available under the major Vyadhi classifications, it is possible to elicit and formulate Nidana Panchaka based on the references of Sthana Roga, Shopha, Granthi, Arbuda etc. The current article is an effort to formulate Nidana Panchaka for Breast Cancer, from the background of basic principles of Ayurveda, for a better analysis and diagnosis of the Vyadhi.


Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 441
Author(s):  
Marcello Cioni ◽  
Alessandro Bertacchini ◽  
Alessandro Mucci ◽  
Nicolò Zagni ◽  
Giovanni Verzellesi ◽  
...  

In this paper, we investigate the evolution of threshold voltage (VTH) and on-resistance (RON) drifts in the silicon carbide (SiC) power metal-oxide-semiconductor field-effect transistors (MOSFETs) during the switch-mode operation. A novel measurement setup for performing the required on-the-fly characterization is presented and the experimental results, obtained on commercially available TO-247 packaged SiC devices, are reported. Measurements were performed for 1000 s, during which negative VTH shifts (i.e., VTH decrease) and negative RON drifts (i.e., RON decrease) were observed. To better understand the origin of these parameter drifts and their possible correlation, measurements were performed for different (i) gate-driving voltage (VGH) and (ii) off-state drain voltage (VPH). We found that VTH reduction leads to a current increase, thus yielding RON to decrease. This correlation was explained by the RON dependence on the overdrive voltage (VGS–VTH). We also found that gate-related effects dominate the parameter drifts at low VPH with no observable recovery, due to the repeated switching of the gate signal required for the parameter monitoring. Conversely, the drain-induced instabilities caused by high VPH are completely recoverable within 1000 s from the VPH removal. These results show that the measurement setup is able to discern the gate/drain contributions, clarifying the origin of the observed VTH and RON drifts.


2021 ◽  
Vol 22 (16) ◽  
pp. 8359
Author(s):  
Loretta Ferrera ◽  
Raffaella Barbieri ◽  
Cristiana Picco ◽  
Paolo Zuccolini ◽  
Alessia Remigante ◽  
...  

Tumor microenvironments are often characterized by an increase in oxidative stress levels. We studied the response to oxidative stimulation in human primary (IGR39) or metastatic (IGR37) cell lines obtained from the same patient, performing patch-clamp recordings, intracellular calcium ([Ca2+]i) imaging, and RT-qPCR gene expression analysis. In IGR39 cells, chloramine-T (Chl-T) activated large K+ currents (KROS) that were partially sensitive to tetraethylammonium (TEA). A large fraction of KROS was inhibited by paxilline—a specific inhibitor of large-conductance Ca2+-activated BK channels. The TEA-insensitive component was inhibited by senicapoc—a specific inhibitor of the Ca2+-activated KCa3.1 channel. Both BK and KCa3.1 activation were mediated by an increase in [Ca2+]i induced by Chl-T. Both KROS and [Ca2+]i increase were inhibited by ACA and clotrimazole—two different inhibitors of the calcium-permeable TRPM2 channel. Surprisingly, IGR37 cells did not exhibit current increase upon the application of Chl-T. Expression analysis confirmed that the genes encoding BK, KCa3.1, and TRPM2 are much more expressed in IGR39 than in IGR37. The potassium currents and [Ca2+]i increase observed in response to the oxidizing agent strongly suggest that these three molecular entities play a major role in the progression of melanoma. Pharmacological targeting of either of these ion channels could be a new strategy to reduce the metastatic potential of melanoma cells, and could complement classical radio- or chemotherapeutic treatments.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4268
Author(s):  
Jessica de Wild ◽  
Gizem Birant ◽  
Guy Brammertz ◽  
Marc Meuris ◽  
Jef Poortmans ◽  
...  

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.


Author(s):  
Zoltán Horváth ◽  
László Vécsei

The current increase in cardiovascular and cerebrovascular morbidity is a growing burden for society. Consideration must therefore be given to compounds capable of slowing down these pathological processes without significant adverse effects. The natural vitamins pantetheine/pantothenic acid are major precursors of coenzyme A and acyl carrier protein, which are essential for fatty acid oxidation and participate in the metabolism of cholesterol and carbohydrates and in at least 70 other enzymatic processes. Following a number of theoretical considerations and clinical observations, various clinical studies have revealed that they possess significant beneficial effects. In particular, they demonstrate useful moderating effects on vascular pathological processes, lowering lipid levels, and inhibiting platelet functions and lipid peroxidation. Although they are natural, well-tolerated therapeutic agents, few controlled clinical trials have been conducted. The available data suggest the need for larger clinical trials and possible use of pantetheine/pantothenic acid as adjuvant therapy.


2021 ◽  
Author(s):  
Marine Prieur ◽  
Alexander C. Whittaker ◽  
Fritz Schlunegger ◽  
Tor O. Sømme ◽  
Jean Braun ◽  
...  

<p>Sedimentary dynamics and fluxes are influenced by both autogenic and allogenic forcings. A better understanding of the evolution of sedimentary systems through time and space requires us to decipher, and therefore to characterise, the impact of each of these on the Earth’s landscape. Given the current increase in the concentration of atmospheric carbon, studying the impact of rapid and global climate changes is of particular importance at the present time. Such events have been clearly defined in the geologic record. Among them, the Paleocene-Eocene Thermal Maximum (PETM) has been extensively studied worldwide and represents a possible analogue of the rapid current climate warming.</p><p>The present project focuses on the Southern Pyrenees (Spain) where excellent exposures of the Paleocene-Eocene interval span a large range of depositional environments from continental to deep-marine. These conditions allow us to collect data along the whole depositional system in order to document changes in sediment fluxes and paleohydraulic conditions. Because hydrological conditions have an impact on sediment transport through hydrodynamics, paleoflow reconstructions can shed light on changes in sediment dynamics. This information is reconstructed from the statistical distributions of channel morphologies, characteristic system dimensions including bankfull channel depth and width, and grain-sizes.</p><p>With this approach, our aim is to provide both qualitative and quantitative assessments of the magnitude and extent of the perturbation of sedimentary fluxes along an entire source-to-sink system during an episode of extreme climate change. This will lead to a better understanding of the impact of abrupt climate change on earth surface systems in mid-latitudinal areas, with possible implications for current climate adaptation policy.</p><p>This research is carried out in the scope of the lead author’s PhD project and is part of the S2S-FUTURE European Marie Skłodowska-Curie ITN (Grant Agreement No 860383).</p>


2018 ◽  
Vol 63 (1) ◽  
pp. 170-178 ◽  
Author(s):  
László Kiss

In this article, the feasibility of the CuxS modified carbon microdisc electrode was examined by exposure to four different volatile organic compounds (2-propanol, acetic acid, ethyl acetate and n-butylamine) directly in their vapour phase using cyclic voltammetry and amperometry. The performance of the modified microdisc was compared with the bare carbon microdisc (30 μm in diameter) which was involved in a narrow-gap cell. By using both methods high current increase was observed for 2-propanol with the modified electrode and its sensitivity was sufficiently higher than with the bare electrode. The modified electrode showed lower current signals in case of acetic acid and n-butylamine. The latter formed a condensation layer at the interelectrode gap. Neither the bare nor the modified electrode was sensitive to ethyl acetate.


2011 ◽  
Vol 300 (5) ◽  
pp. H1806-H1813 ◽  
Author(s):  
Alberto Corrias ◽  
Wayne Giles ◽  
Blanca Rodriguez

Purkinje cells play an important role in drug-induced arrhythmogenesis and are widely used in preclinical drug safety assessments. Repolarization abnormalities such as action potential (AP) prolongation and early afterdeploarizations (EAD) are often observed in vitro upon pharmacological interventions. However, because drugs do not act on only one defined target, it is often difficult to fully explain the mechanisms of action and their potential arrhythmogenicity. Computational models, when appropriately detailed and validated, can be used to gain mechanistic insights into the mechanisms of action of certain drugs. Nevertheless, no model of Purkinje electrophysiology that is able to reproduce characteristic Purkinje responses to drug-induced changes in ionic current conductances such as AP prolongation and EAD generation currently exists. In this study, a novel biophysically detailed model of rabbit Purkinje electrophysiology was developed by integration of data from voltage-clamp and AP experimental recordings. Upon validation, we demonstrate that the model reproduces many key electrophysiological properties of rabbit Purkinje cells. These include: AP morphology and duration, both input resistance and rate dependence properties as well as response to hyperkalemia. Pharmacological interventions such as inward rectifier K+ current and rapid delayed rectifier K+ current block as well as late Na+ current increase result in significant AP changes. However, enhanced L-type Ca2+ current ( iCaL) dominates in EAD genesis in Purkinje fibers. In addition, iCaL inactivation dynamics and intercellular coupling in tissue strongly modulate EAD formation. We conclude that EAD generation in Purkinje cells is mediated by an increase in iCaL and modulated by its inactivation kinetics.


2001 ◽  
Vol 670 ◽  
Author(s):  
Akira Nishiyama ◽  
Akio Kaneko ◽  
Masato Koyama ◽  
Yoshiki Kamata ◽  
Ikuo Fujiwara ◽  
...  

ABSTRACTTi-Si-O films were sputter deposited from TiO2+SiO2 composite targets with various SiO2 content. The phase separation occurred for every SiO2 content used in this experiment (from 14% to 75%) and it has been revealed that nanocrystalline (TiO2)1-x(SiO2)x films in which anatase TiO2 forms tiny grains were obtained when x in the film is larger than 0.26. The tiny grain was effective for suppressing the thermal grooving phenomenon of the thin films by the post deposition annealing which leads to the leakage current increase. The dielectric constant of the nanocrystalline film was varied with the SiO2 content from the value of the bulk anatase to SiO2.


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