scholarly journals Wpływ pandemii COVID-19 na funkcjonowanie regionalnego transportu kolejowego obszarów przygranicznych – na przykładzie województwa dolnośląskiego (PL) i kraju libereckiego (CZ)

2021 ◽  
Vol 92 (1) ◽  
pp. 121-140
Author(s):  
Mateusz Smolarski ◽  
Michał Suszczewicz
Keyword(s):  
Na Transport

Systemy zbiorowego transportu publicznego są narażone na wiele zewnętrznych czynników wpływających na ich funkcjonowanie. Jednym z nich może być zagrożenie epidemiologiczne. W 2020 r. światowa pandemia COVID-19 miała istotny wpływ na światową gospodarkę oraz przewozy pasażerskie. Wprowadzone liczne ograniczenia wpłynęły na popyt (liczbę pasażerów) oraz podaż (oferta przewozowa) na rynku transportu. Do najczęstszych obostrzeń zaliczyć można: ograniczenie liczby połączeń, zmniejszenie limitu pasażerów w pojeździe, ograniczenie siatki połączeń komunikacyjnych. W analizie autorzy przeprowadzili badanie województwa dolnośląskiego oraz kraju libereckiego w kontekście zmian w funkcjonowaniu regionalnego transportu kolejowego. Spadek liczby kursów dotyczył nie tylko linii peryferyjnych (kraj liberecki), ale również głównych tras w regionie (Dolny Śląsk). W Czechach alternatywnym środkiem transportu mogły być przewozy autobusowe. Powrót do poziomu stanu sprzed ograniczeń przewozowych powinien być związany z zachęcaniem pasażerów do ponownego korzystania z transportu kolejowego. Długotrwały spadek poziomu obsługi komunikacyjnej mógł skłonić mieszkańców do wyboru alternatywnych środków transportu (np. samochód). Stabilność oferty przewozowej stanowi jeden z filarów wysokiego popytu na transport publiczny. Czynnik zewnętrzny (pandemia) nie powinien być powodem radykalnych redukcji siatki połączeń. W niektórych przypadkach może to przynosić odwrotne skutki, np. wzrost zatłoczenia w godzinach szczytu (dojazdy do pracy). Analiza wykazała, że skoordynowane (zintegrowane) systemy transportu publicznego są lepiej przygotowane na potencjalne zagrożenia zewnętrzne niż model oparty na słabej pozycji organizatora przewozów. W Polsce samorząd wojewódzki ma duży wpływ na transport kolejowy, ale bardzo słaby na przewozy autobusowe. Model czeski z kolei oparty jest na regionalnej koordynacji obu środków transportu.

The Sigma-1 Receptor Ligands Chlorpromazine and Trifluoperazine Inhibit Na+ Transport in Frog Skin Epithelium

BIOPHYSICS ◽  
2020 ◽  
Vol 65 (5) ◽  
pp. 784-787
Author(s):  
A. V. Melnitskaya ◽  
Z. I. Krutetskaya ◽  
V. G. Antonov ◽  
N. I. Krutetskaya
Keyword(s):  
Frog Skin ◽  
Receptor Ligands ◽  
Na Transport ◽  
Sigma 1 Receptor ◽  
Skin Epithelium ◽  
Frog Skin Epithelium ◽  
Sigma 1

Use of Isolated Tight Epithelia to Study the Site and Mode of Drug Action on Cell Membrane Transport: Effect of the Antipsychotic Agent Trifluoperazine

1990 ◽  
Vol 17 (3) ◽  
pp. 224-227
Author(s):  
Henning F. Bjerregaard
Keyword(s):  
Cell Membrane ◽  
Toxic Effect ◽  
Membrane Transport ◽  
Antipsychotic Agent ◽  
Na Transport ◽  
Tight Epithelia ◽  
Acute Toxic Effect ◽  
Cell Membrane Transport ◽  
Dose Dependent ◽  
Stimulation Of

The aim of the present study was to investigate the site and mode of trifluoperazine (TFP) action on cell membrane transport by the use of isolated frog skin. This cellular system gives access to the apical (outer) and basolateral (inner) membranes of the polarised epithelial cells. Both apical and basolateral TFP addition induced a dose-dependent stimulation of Na transport, and depolarised the cellular potential. The data indicate that TFP acts by increasing the Na permeability of the apical membrane. However, the mechanisms localised in the apical and basolateral membranes are quite different. Basolateral TFP addition increased Na transport due to a stimulation of PGE2 synthesis, whereas apical TFP addition abolished Na inhibition of the apical Na channels, and thereby enhanced the Na transport. An acute toxic effect on the electrophysiological parameters was noted after addition of high apical TFP concentrations (50–100μM). This toxic effect was dependent on the presence of Na in the apical solution.

Synthesis, characterization, electrical properties, and Na+ transport pathways simulation in Na2ZnP1.5As0.5O7

Ionics ◽  
2021 ◽  
Author(s):  
Yossra Sallemi ◽  
Riadh Marzouki ◽  
Youssef Ben Smida ◽  
Adel A. El-zahhar ◽  
Mohsen Graia
Keyword(s):  
Electrical Properties ◽  
Na Transport ◽  
Transport Pathways

scholarly journals Effects of butyrate on histone deacetylation and aldosterone-dependent Na+ transport in the toad bladder.

1983 ◽  
Vol 258 (5) ◽  
pp. 3388-3395
Author(s):  
A Truscello ◽  
K Geering ◽  
H P Gäggeler ◽  
B C Rossier
Keyword(s):  
Histone Deacetylation ◽  
Toad Bladder ◽  
Na Transport

pHi determines rate of sodium transport in frog skin: results of a new method to determine pHi

1994 ◽  
Vol 266 (3) ◽  
pp. F367-F374 ◽  
Author(s):  
R. Rick
Keyword(s):  
Frog Skin ◽  
Nuclear Potential ◽  
Na Channel ◽  
Cytoplasmic Ph ◽  
Na Transport ◽  
Principal Cells ◽  
Weak Organic Acid ◽  
Transepithelial Na Transport ◽  
Cell Layers ◽  
Important Regulator

The pH of the isolated frog skin epithelium was determined on a cellular and subcellular level based on the distribution of a weak organic acid, 4-bromobenzoic acid. The indicator is detectable by X-ray microanalysis due to the presence of an element label. The results show that the pH of principal cells, but not the Na concentration, is closely correlated with the rate of transepithelial Na transport. Acidification leads to an inhibition of Na transport, regardless of whether the change was spontaneous or experimentally induced. Under the conditions of this study, the pH of principal cells was not well regulated. At a bath pH of 7.0, large pH differences between the cell layers were detectable. In mitochondria-rich cells, the pH was a function of the intracellular Cl concentration but not the Na transport rate. The cytoplasmic pH consistently exceeded the nuclear pH. The nuclear-cytoplasmic pH differential in principal cells amounted to 0.3 pH units, which is equivalent to a nuclear potential of -17 mV. The results support the view that the intracellular pH (pHi) is an important regulator of transepithelial Na transport. Regulation is primarily achieved at the level of the apical Na channel, making the Na influx the rate-limiting step in Na reabsorption.

scholarly journals Na+ Transporter SvHKT1;1 from a Halophytic Turf Grass Is Specifically Upregulated by High Na+ Concentration and Regulates Shoot Na+ Concentration

2020 ◽  
Vol 21 (17) ◽  
pp. 6100
Author(s):  
Yuki Kawakami ◽  
Shahin Imran ◽  
Maki Katsuhara ◽  
Yuichi Tada
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Early Stage ◽  
Constitutive Expression ◽  
Xenopus Laevis Oocytes ◽  
Na Transport ◽  
Turf Grass ◽  
Defective Mutant ◽  
Reduced Salt ◽  
Na Uptake

We characterized an Na+ transporter SvHKT1;1 from a halophytic turf grass, Sporobolus virginicus. SvHKT1;1 mediated inward and outward Na+ transport in Xenopus laevis oocytes and did not complement K+ transporter-defective mutant yeast. SvHKT1;1 did not complement athkt1;1 mutant Arabidopsis, suggesting its distinguishable function from other typical HKT1 transporters. The transcript was abundant in the shoots compared with the roots in S. virginicus and was upregulated by severe salt stress (500 mM NaCl), but not by lower stress. SvHKT1;1-expressing Arabidopsis lines showed higher shoot Na+ concentrations and lower salt tolerance than wild type (WT) plants under nonstress and salt stress conditions and showed higher Na+ uptake rate in roots at the early stage of salt treatment. These results suggested that constitutive expression of SvHKT1;1 enhanced Na+ uptake in root epidermal cells, followed by increased Na+ transport to shoots, which led to reduced salt tolerance. However, Na+ concentrations in phloem sap of the SvHKT1;1 lines were higher than those in WT plants under salt stress. Based on this result, together with the induction of the SvHKT1;1 transcription under high salinity stress, it was suggested that SvHKT1;1 plays a role in preventing excess shoot Na+ accumulation in S. virginicus.

scholarly journals EFFECT OF CHOLERA TOXIN ON Na TRANSPORT IN INTESTINE

1974 ◽  
Vol 8 (11) ◽  
pp. 909-909
Author(s):  
J F Desjeux ◽  
Y H Tai ◽  
Peter F Curran ◽  
H Lestradet
Keyword(s):  
Cholera Toxin ◽  
Na Transport

Effects of dietary Ca2+ on erythrocyte Na+-transport systems in spontaneously hypertensive rats

1991 ◽  
Vol 81 (1) ◽  
pp. 107-112 ◽  
Author(s):  
K. Fujito ◽  
M. Yokomatsu ◽  
N. Ishiguro ◽  
H. Numahata ◽  
Y. Tomino ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Transport Systems ◽  
Hypertensive Rats ◽  
Na Transport ◽  
Spontaneously Hypertensive ◽  
Na Pump ◽  
Wistar Kyoto ◽  
Increased Activity ◽  
Regulation Of Blood Pressure

1. The purpose of this study was to determine the effect of dietary Ca2+ intake on blood pressure and erythrocyte Na+ transport in spontaneously hypertensive rats. 2. Spontaneously hypertensive rats and Wistar-Kyoto rats were fed diets with three different Ca2+ contents, 0.1% (low-Ca2+ diet), 0.6% (normal-Ca2+ diet) and 4.0% (high-Ca2+ diet), between 6 and 20 weeks of age. At 20 weeks of age, the levels of erythrocyte Na+ efflux, as well as Na+ and K+ contents in erythrocytes, were measured. 3. On the low-Ca2+ diet, spontaneously hypertensive rats showed an enhancement of hypertension. Conversely, on the high-Ca2+ diet, they showed an attenuation of the increase in blood pressure. Spontaneously hypertensive rats had a lower erythrocyte Na+ content and increased activity of the Na+ pump at higher levels of dietary Ca2+. Passive Na+ permeability and Na+-K+ co-transport were similar in spontaneously hypertensive rats on the low-, normal- and high-Ca2+ diets. There were no significant differences in blood pressure and in Na+ pump activity in WKY on the three different diets. 4. It is concluded that dietary Ca2+ might affect the regulation of blood pressure in spontaneously hypertensive rats by changing the activity of Na+ pump in the cell membrane.

Sign in / Sign up

Export Citation Format

Share Document