10-s Period Research Articles

Effects of cerebellar transcranial alternating current stimulation in cerebellar ataxia: study protocol for a randomised controlled trial.

Cerebellar ataxia (CA) is a movement disorder that can affect balance and gait, limb movement, oculomotor control, and cognition. Multiple system atrophy-cerebellar type (MSA-C) and spinocerebellar ataxia type 3 (SCA3) are the most common forms of CA, for which no effective treatment is currently available. Transcranial alternating current stimulation (tACS) is a non-invasive method of brain stimulation supposed to alter cortical excitability and brain electrical activity, modulating functional connectivity within the brain. The cerebellar tACS can modulate the cerebellar outflow and cerebellum-linked behavior and it is a proven safe technique for humans. Therefore, the aim of this study is to 1) examine whether cerebellar tACS improves ataxia severity and various non-motor symptoms in a homogeneous cohort of CA patients consisting of MSA-C and SCA3, 2) explore the time course of these effects, and 3) assess the safety and tolerance of cerebellar tACS in all participants. This is a 2-week, triple-blind, randomised, sham-controlled study. 164 patients (MSA-C: 84, SCA3: 80) will be recruited and randomly assigned to either active cerebellar tACS or sham cerebellar tACS, in a 1:1 ratio. Patients, investigators, and outcome assessors are unaware of treatment allocation. Cerebellar tACS (40 min, 2 mA, ramp-up and down periods of 10s each) will be delivered over 10 sessions, distributed in two groups of five consecutive days with a two-day break in between. Outcomes are assessed after the tenth stimulation (T1), and after 1 month (T2) and 3 months (T3). The primary outcome measure is the difference between the active and sham groups in the proportion of patients with an improvement of 1.5 points in the Scale for the Assessment and Rating of Ataxia (SARA) score after 2 weeks of treatment. In addition, effects on a variety of non-motor symptoms, quality of life, and autonomic nerve dysfunctions are assessed via relative scales. Gait imbalance, dysarthria, and finger dexterity are objectively valued via relative tools. Finally, functional magnetic resonance imaging is performed to explore the possible mechanism of treatment effects. The results of this study will inform whether repeated sessions of active cerebellar tACS benefit CA patients and whether this form of non-invasive stimulation might be a novel therapeutic approach to consider in a neuro-rehabilitation setting.Clinical Trial Registration: ClinicalTrials.gov, identifier NCT05557786; https://www.clinicaltrials.gov/ct2/show/NCT05557786.

Transient heat transfer performance of Z-pinch driven fusion-fission hybrid energy reactor blanket

Z-pinch driven fusion-fission hybrid energy reactor (Z-FFR) is a new energy system, which is helpful to the sustainable development of nuclear energy. It runs in a pulsed mode with a period of 10s, in order to output a mean thermal power of 3000 MWt, a large quantity of energy has to be generated in a pulse. The transient heat transfer and temperature variation of the blanket and first wall in the strong heat shock situation are key issues to the technical feasibility of Z-FFR. In this paper, the temperature variation of blanket and first wall under consecutive heat pulse is analyzed through numerical simulation. Meanwhile, with the aim of exporting electric power stably, a simple method of stabilizing the output power is proposed, and the fluctuation character of the outflow in the main pipe is described. The results show that, the maximum temperatures of all materials are in the safety margin, the thickness of the layer that has a relative high temperature on the surface of the first wall is about 0.5 mm, the output power has a fluctuation of -2.84% to +2.05% relative to the nominal value.

SU‐D‐18A‐05: Assessing Elekta MLC Tracking Performance

Purpose:To investigate the technical feasibility of using Elekta MLCs in tracked radiotherapy, specifically to show the capability of an Agility MLC to follow model tumor trajectories using object tracking. The system performance of the MLC is to be assessed via dosimetric experiments and temporal response measures.Methods:The system observer in the tracking cascade consisted of a camera serving for this proof of concept; Images of a moving object were acquired continuously and decorrelated for the position information, which was fed forward to the RT computer controlling the MLC via an interface provided by Elekta. The 1D motion (in the direction of the leaves) was induced by a CIRS motion controller. Additionally, the aperture position was observed by means of the light field of the linac. Calculating the phase between aperture and object yielded the mean aperture lag for the current setup. The object was restricted to sinusoidal motion with a period of 10s. For dosimetry, GafChromic radiosensitive film was irradiated with a total dose of 1000MU using an aperture size of 40mm and a motion range of 30mm.Results:Object tracking can substantially reconstruct the geometric dose response of a static target. In the dynamic case, dose is smeared out into the legs of the static distribution, leading to a reduced plateau and increased FWHM of 5mm, compared to the static width of 38mm. The time‐lag between object and aperture was determined to be approximately 300ms for the current set‐up.Conclusion:We demonstrated a tracking experiment performed on a clinical Elekta linear accelator for the first time. Observed profile variations show the dosimetric impact of tracked delivery. The determined lag is a valuable descriptor for a future tracking cascade employing predictor filters. The performed experiments are generic and possible predecessors for future applications with MR‐Linac or ultrasound probes.Conflict of interest: this project is partly funded by Elekta.

Design of a compact, aluminum, tungsten-coil electrothermal vaporization device for inductively coupled plasma-optical emission spectrometry

A new compact, aluminum electrothermal vaporization cell was constructed for inductively coupled plasma-optical emission spectrometry analysis. This cell is compact enough to fit within the space occupied by the spray chamber and fits directly to the quartz torch without extraneous tubing through the use of a simple Compression fitting. Sample volumes as low as 10μL were analyzed with an automated control program for efficient vaporization. Twelve elements were analyzed utilizing a time resolved acquisition method so that real-time data could be generated over a period of 10s with an average improvement factor of 14 for elements over a wavelength range of 193–445nm.

Sympathetic influence on intraocular pressure

Abstract Purpose To apply wavelet analysis to investigate the sympathetic modulation upon intraocular pressure(IOP)of the cold pressure test Methods In an autonomic dedicated lab continuous and simultaneous recording of(IOP) with Pascal(DCT) and arterial blood pressure(BP) were made in 11 healthy individuals,of both sexes,in basal conditions and during 1minute of cold‐pressure test(CPT).The tests were in the morning period and in the 24h previous individuals were told not to smoke and to avoid xanthines or other stimulants ingestion. Individuals under medication or with other pathology that could affect the autonomic nervous system were excluded. Data analysis of IOP and systolicBP (SBP) in the time‐scale domain with wavelets(DB12)was performed, for both variables, during the last minute prior to test and during one minute upon test. In this last case,periods of 10s where individually analysed and the period with the largest value was the chosen for statist analysis using t‐Student test, Welch corrected(Ducla‐Soares et al, 2007).LFIOP and LFSBP were calculated and differences between basal and CPT values were considered significant where p<0.05. Data were expressed as mean±SEM., and for LF mmHg2 Results Data refer to 6 male and 5 female with a mean age of 49[40‐70] On CPT, a sympathetic challenging manoeuvre, an increase of SBP was observed. Wavelet analysis of both signals showed a significant increase of LFIOP and LFSBP from 0.13±0.15 and 8.66±1.51 to 0.37±0.26 mmHg2 and 18.7±4.5mmHg2, respectively, and a not significant change in IOP 17.0±2.6 to18.0±1.5 Conclusion Our data show a sympathetic signature on IOP correlated with that observed in BP. We show that wavelets are a suitable tool for the evaluation of sympathetic signature on short periods of IOP recorded by DCT

Metabolic consequences of living in a wave-swept environment: Effects of simulated wave forces on oxygen consumption, heart rate, and activity of the shell adductor muscle of the abalone Haliotis iris

Animals in wave-exposed habitats must constantly contend with the hydrodynamic forces of lift and drag. In this study, we investigated aspects of the metabolic response of Haliotis iris to simulated wave forces varying in magnitude up to 9.6 N applied to the shell at 69° to horizontal, alternately from anterior and posterior directions, with a period of 10s. Shell adductor muscle activity (electromyogram, EMG), heart rate, and oxygen consumption were monitored during force application and during extended recovery. EMG spiking was absent at zero force, but increased markedly with increasing force, in synchrony with the wave cycle. In contrast, heart rate was unaffected by wave forces and varied by only 5% over the whole range of applied forces. During force application, oxygen consumption increased by 10–25% above resting rates and remained elevated throughout a 5-hour recovery period, indicating a switch to anaerobic metabolism. It is concluded that living in a wave-swept environment is metabolically costly for abalone although this may be compensated by improved food availability and more efficient ventilation induced by external flow.

Thermotherapy: feasibility study using a single focussed ultrasound transducer

Feasibility studies on tissue lesioning using high intensity focussed ultrasound (HIFU) thermotherapy were carried out. A single strongly focussed transducer was used. The transducer has a diameter of 50mm, a centre resonance frequency of 1MHz and a focal distance of 50mm. Experiments were carried out both in vitro on pig muscle samples and in vivo on a pig (exposures on the thigh and on the liver). Different types of burst pulse signals were used, the best results were obtained with 1-2s burst pulses, with a repetition period of 10s. The risk for skin damage increases for longer burst pulses. Lesions at the focus were obtained both in the experiments in vitro as well as in vivo . The size and the shape of the lesions in vivo resemble those obtained in vitro . The results of the experiments show that tissue lesions can be obtained at deep locations (4.5cm in the tissue) with the transducer. The lesions were well discriminated from the surrounding tissue and were ellipsoid- or drop-shaped. The lesion size can be controlled by the choice of time parameters of the burst pulse signal, power and treatment time. Temperatures of about 80oC were measured in the tissue at the ultrasound focus in vitro . These results show that elevated temperatures can be induced rapidly at the focus, thus reducing the effect of heat dissipation through blood perfusion.

Long-Period Magnetotelluric Measurements Near the Central California Coast: A Land-Locked View of the Conductivity Structure Under the Pacific Ocean

SUMMARY Telluric data from Hollister, California were combined with magnetic data from the Fresno, California magnetic observatory to determine the MT response at long periods. The shifted eigenstate analysis of LaTorraca et al. (1986) was used to determine the maximum apparent resistivities and corresponding EIH phases for periods from 1 to 30 h. The apparent resistivity and phase at Hollister are greatly influenced by the ocean, with the mantle branch beginning at a period of about 12 h. In typical continental areas, the mantle branch usually begins at periods of 10s or less. A maximum likelihood inversion algorithm was used to invert the observed data and to determine the sensitivity of the model parameters. The data required a resistivity-thickness product of approximately 1 x lo9 Q-m2 (1 x lo6 Q-m-km) for the oceanic lower crust and upper mantle. The oceanic mantle shows a rather small gradient of conductivity from approximately 200 to 640 km in depth, and a rapid conductivity increase below 640km. The sensitivity analysis shows the data are most sensitive to the oceanic parameters, except for the electric field amplitudes which are also sensitive to the resistivities under the observation site.

Characteristics of electron-free plasma confinement in an rf quadrupole field

A low-density plasma composed solely of massive atomic ions, namely Tl+ and I−, was produced by photodissociation of molecular TlI at low pressure, using the powerful 206 nm atomic iodine emission line, and confined in a Paul rf quadrupole electric field. A simple theoretical model based on an infinite homogeneous plasma of low density is used to estimate the perturbation of the ion oscillation frequencies in the external field due to the electrostatic interaction between the ions. The decay characteristics of the plasma under ionic recombinations were observed over a period of 10s, and the absolute ion density determined to be 1.1×107 cm−3 with a maximum energy on the order of 5 eV.