scholarly journals Long-Term Effect of Low-Frequency Electromagnetic Irradiation in Water and Isotonic Aqueous Solutions as Studied by Photoluminescence from Polymer Membrane

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1443
Author(s):  
Nikolai F. Bunkin ◽  
Polina N. Bolotskova ◽  
Elena V. Bondarchuk ◽  
Valery G. Gryaznov ◽  
Sergey V. Gudkov ◽  
...  
Keyword(s):  
Low Frequency ◽  
Polymer Membrane ◽  
Deionized Water ◽  
Time Interval ◽  
Platinum Electrodes ◽  
Electromagnetic Treatment ◽  
Long Term Effect ◽  
Surface Liquid ◽  
Reference Samples

The swelling of a polymer membrane NafionTM in deionized water and isotonic NaCl and Ringer’s solutions was studied by photoluminescent spectroscopy. According to our previous studies, the surface of this membrane could be considered as a model for a cellular surface. Liquid samples, in which the membrane was soaked, were subjected to preliminary electromagnetic treatment, which consisted of irradiating these samples with electric rectangular pulses of 1 µs duration using platinum electrodes immersed in the liquid. We used a series of pulses with a repetition rate of 11–125 Hz; the pulse amplitudes were equal to 100 and 500 mV. It turned out that at certain pulse repetition rates and their amplitudes, the characteristic swelling time of the polymer membrane significantly differs from the swelling time in untreated (reference) samples. At the same time, there is no effect for certain frequencies/pulse amplitudes. The time interval between electromagnetic treatment and measurements was about 20 min. Thus, in our experiments the effects associated with the long-term relaxation of liquids on the electromagnetic processing are manifested. The effect of long-term relaxation could be associated with a slight change in the geometric characteristics of bubston clusters during electromagnetic treatment.

scholarly journals On the Procedure of Draught Rate Assessment in Indoor Spaces

2020 ◽  
Vol 10 (15) ◽  
pp. 5036
Author(s):  
Detelin Markov ◽  
Nikolay Ivanov ◽  
George Pichurov ◽  
Marina Zasimova ◽  
Peter Stankov ◽  
...  
Keyword(s):  
Thermal Environment ◽  
Low Frequency ◽  
High Amplitude ◽  
Time Interval ◽  
Cfd Simulations ◽  
Reliable Assessment ◽  
Unsteady Rans ◽  
Computational Fluid Dynamics Cfd ◽  
Indoor Spaces

The objective of the paper is to demonstrate the importance of the unsteady Computational Fluid Dynamics (CFD) simulations and long-term measurements for the reliable assessment of thermal comfort indoors, for proper categorization of the indoor thermal environment and for identifying the reasons for complaints due to draught discomfort. Numerical simulations and experimental measurements were applied in combination to study ventilation in a field laboratory, a university classroom with a controlled indoor environment. Strong unsteadiness of the airflow was registered both in the unsteady RANS results and the real-scale long-term velocity data measured with thermo anemometer. Low-frequency high-amplitude velocity fluctuations observed lead to substantial time variation of the draught rate. In case of categorization of a thermal environment, the point measurements or steady-state RANS computations would lead to wrong conclusions as well as they cannot be used for identification of the reasons for people’s complaints due to draught discomfort if strong unsteadiness of the airflow exists. It is demonstrated that the length of the time interval for draught rate (DR) assessment may not be universal if low-frequency high-amplitude pulsations are present in the room airflow.

scholarly journals A 2-decade (1988–2009) record of diatom fluxes in the Mauritanian coastal upwelling: impact of low-frequency forcing and a two-step shift in the species composition

2021 ◽  
Vol 18 (5) ◽  
pp. 1873-1891
Author(s):  
Oscar E. Romero ◽  
Simon Ramondenc ◽  
Gerhard Fischer
Keyword(s):  
Coastal Waters ◽  
Temporal Dynamics ◽  
Southern Oscillation ◽  
Low Frequency ◽  
Meridional Overturning Circulation ◽  
Benthic Diatoms ◽  
Time Interval ◽  
Data Set ◽  
The Impact

Abstract. Eastern boundary upwelling ecosystems (EBUEs) are among the most productive marine regions in the world's oceans. Understanding the degree of interannual to decadal variability in the Mauritania upwelling system is crucial for the prediction of future changes of primary productivity and carbon sequestration in the Canary Current EBUE as well as in similar environments. A multiyear sediment trap experiment was conducted at the mooring site CBmeso (“Cape Blanc mesotrophic”, ca. 20∘ N, ca. 20∘40′ W) in the highly productive coastal waters off Mauritania. Here, we present results on fluxes of diatoms and the species-specific composition of the assemblage for the time interval between March 1988 and June 2009. The temporal dynamics of diatom populations allows the proposal of three main intervals: (i) early 1988–late 1996, (ii) 1997–1999, and (iii) early 2002–mid 2009. The Atlantic Multidecadal Oscillation (AMO) appears to be an important driver of the long-term dynamics of diatom population. The long-term AMO-driven trend is interrupted by the occurrence of the strong 1997 El Niño–Southern Oscillation (ENSO). The extraordinary shift in the relative abundance of benthic diatoms in May 2002 suggests the strengthening of offshore advective transport within the uppermost layer of filament waters and in the subsurface and in deeper and bottom-near layers. It is hypothesized that the dominance of benthic diatoms was the response of the diatom community to the intensification of the slope and shelf poleward undercurrents. This dominance followed the intensification of the warm phase of AMO and the associated changes of the Atlantic Meridional Overturning Circulation. Transported valves (siliceous remains) from shallow Mauritanian coastal waters into the bathypelagic should be considered for the calculation and model experiments of bathy- and pelagic nutrients budgets (especially Si), the burial of diatoms, and the paleoenvironmental signal preserved in downcore sediments. Additionally, our 1988–2009 data set contributes to the characterization of the impact of low-frequency climate forcings in the northeastern Atlantic and will be especially helpful for establishing the scientific basis for forecasting and modeling future states of the Canary Current EBUE and its decadal changes.

scholarly journals Low-frequency lower E-region wind and reflection height measurements as sensor for climate variability

2008 ◽  
Vol 6 ◽  
pp. 331-335 ◽  
Author(s):  
C. Jacobi
Keyword(s):  
Oblique Incidence ◽  
Lower Thermosphere ◽  
Low Frequency ◽  
Time Interval ◽  
Radio Waves ◽  
Reflection Height ◽  
E Region ◽  
Long Term Trends ◽  
Mlt Region

Abstract. Measurements of reflection heights of low-frequency (LF) radio waves at oblique incidence and estimates of mesosphere/lower thermosphere (MLT) region horizontal winds applying the D1 spaced receiver method on LF field strength registrations are analyzed with respect to possible long-term trends and interdecadal variability in the time interval from ~1980 to date. While no clear signal of mesospheric height trend is registered during the last two decades, significant trends of MLT horizontal winds are found. These trends are non-linear, in particular a change of trends around 1990 is found, which is probably connected with changes in tropospheric and stratospheric conditions at that time.

scholarly journals Repetitive Transcranial Magnetic Stimulation for Tinnitus Treatment in Vestibular Schwannoma: A Pilot Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Maria Teresa Leao ◽  
Kathrin Machetanz ◽  
Joey Sandritter ◽  
Marina Liebsch ◽  
Andreas Stengel ◽  
...  
Keyword(s):  
Pilot Study ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Acute Effect ◽  
Term Effect ◽  
Long Term Effect ◽  
The Right ◽  
Low Frequency Rtms ◽  
Present Pilot Study

Background: Vestibular schwannomas (VS) are brain tumors affecting the vestibulocochlear nerve. Thus, VS patients suffer from tinnitus (TN). While the pathophysiology is mainly unclear, there is an increasing interest in repetitive transcranial magnetic stimulation (rTMS) for TN treatment. However, the results have been divergent. In addition to the methodological aspects, the heterogeneity of the patients might affect the outcome. Yet, there is no study evaluating rTMS exclusively in VS-associated tinnitus. Thus, the present pilot study evaluates low-frequency rTMS to the right dorsolateral pre-frontal cortex (DLPFC) in a VS-associated tinnitus.Methods: This prospective pilot study enrolled nine patients with a monoaural VS-associated tinnitus ipsilateral to the tumor. Patients were treated with a 10-day rTMS regime (1 Hz, 100% RMT, 1,200 pulses, right DLPFC). The primary endpoint of the study was the reduction of TN distress (according to the Tinnitus Handicap Inventory, THI). The secondary endpoint was a reduction of TN intensity (according to the Tinnitus Matching Test, TMT) and the evaluation of factors predicting tinnitus outcome (i.e., hearing impairment, TN duration, type of tinnitus).Results: No complications or side effects occurred. There was one drop-out due to a non-responsiveness of the complaint. There was a significant acute effect of rTMS on the THI and TMT. However, there was no significant long-term effect after 4 weeks. While the THI failed to detect any clinically relevant acute effect of rTMS in 56% of the patients, TMT revealed a reduction of TN intensity for more than 20 in 89% and for more than 50 in 56% of the patients. Notably, the acute effect of rTMS was influenced by the TN type and duration. In general, patients with a tonal TN and shorter TN duration showed a better response to the rTMS therapy.Conclusion: The present pilot study is the first one to exclusively evaluate the effect of low-frequency rTMS to the right DLPFC in a VS-associated tinnitus. Our results prove the feasibility and the efficacy of rTMS in this patient cohort. There is a significant acute but a limited long-term effect. In addition, there is evidence that patients with a tonal tinnitus and shorter tinnitus duration might have the strongest benefit. A larger, randomized controlled study is necessary to prove these initial findings.

A long-term effect of subliminally presented words

2010 ◽  
Author(s):  
Andreas T. Breuer ◽  
Michael E. J. Masson ◽  
Glen E. Bodner
Keyword(s):  
Term Effect ◽  
Long Term Effect
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