Hz Of Frequency Research Articles

Relationships among low frequency (2 Hz) electrical resistivity, porosity, clay content and permeability in reservoir sandstones

The improved interpretation of marine controlled source electromagnetic (CSEM) data requires knowledge of the inter-relationships between reservoir parameters and low frequency electrical resistivity. Hence, the electrical resistivities of 67 brine (35g/l) saturated sandstone samples with a range of petrophysical properties (porosity from 2% to 29%, permeability from 0.0001mD to 997.49mD and volumetric clay content from 0 to 28%) were measured in the laboratory at a frequency of 2Hz using a four-electrode circumferential resistivity method with an accuracy of ±2%. The results show that sandstones with porosity higher than 9% and volumetric clay content up to 22% behave like clean sandstones and follow Archie's law for a brine concentration of 35g/l. By contrast, at this brine salinity, sandstones with porosity less than 9% and volumetric clay content above 10% behave like shaly sandstones with non-negligible grain surface conductivity. A negative, linear correlation was found between electrical resistivity and hydraulic permeability on a logarithmic scale. We also found good agreement between our experimental results and a clay pore blocking model based on pore-filling and load-bearing clay in a sand/clay mixture, variable (non-clay) cement fraction and a shaly sandstone resistivity model. The model results indicate a general transition in shaly sandstones from clay-controlled resistivity to sand-controlled resistivity at about 9% porosity. At such high brine concentrations, no discernible clay conduction effect was observed above 9% porosity.

Dynamic mechanical thermal properties of the dental light-cured nanohybrid composite Kalore, GC: Effect of various food/oral simulating liquids

ObjectiveThe aim of this work is the study of the dynamic mechanical thermal properties (viscoelastic properties) of a current dental commercial light-cured nanohybrid resin composite, Kalore, GC (GC Corporation, Tokyo, Japan) along with the study of the effect of some food/oral simulating liquids (FSLs) on these properties. MethodsDynamic mechanical thermal analysis (DMTA) tests were performed on a Diamond Dynamic Mechanical Thermal Analyzer in bending mode. A frequency of 1Hz and a temperature range of 25–185°C were applied, while the heating rate of 2°C/min was selected to cover mouth temperature and the material's likely Tg. The properties were determined after storage in air, distilled water, heptane, ethanol/water solution (75% v/v) or absolute ethanol at 37°C for up to 1h, 1, 7 or 30 days. ResultsStorage modulus, loss modulus and tangent delta (tanδ) were plotted against temperature. The glass transition temperatures are taken from the peak of the tangent tanδ versus temperature curves. Moreover, some factors indicating the heterogeneity of the polymer matrix, such as the width (ΔT) at the half of tanδ peak and the “ζ” parameter were determined. All samples analyzed after storage for 1h or 1 day in the aging media showed two Tg values. All samples analyzed after storage for 7 or 30 days in the ageing media showed a unique Tg value. SignificanceStorage of Kalore GC in dry air, water or heptane at 37°C for 7 days caused post-curing reactions. Storage in air or water for 30 days did not seem to cause further effects. Storage in heptane for 30 days may cause plasticization and probably some degradation of the filler–silane bond and polymer matrix. Storage in ethanol/water solution (75% v/v) or ethanol for 7 days seems to cause post-curing reactions and degradation reactions of the matrix–filler bonds. Storage in ethanol for 30 days caused a strong change of the sample morphology and the DMTA results were not reliable.

Effectiveness of Pulsed Radiofrequency with Multifunctional Epidural Electrode in Chronic Lumbosacral Radicular Pain with Neuropathic Features

Background: Lumbosacral radicular pain is a common clinical finding with a statistical prevalence ranging from 9.9% to 25% in the general population. Objective: To investigate the effectiveness of dorsal root ganglion pulsed radiofrequency (PRF) in patients with chronic lumbosacral radicular pain and neuropathic features. Study Design: Prospective case series clinical outcome study. Methods: We evaluated 34 patients with lumbosacral neuropathic pain who underwent PRF at the corresponding level of radicular symptoms distribution (ranging from L3 to S1). Each patient suffered a single leg-radiating pain with probable neuropathic features (assessed with clinical grading) lasting for > 6 months and unresponsive to previous treatments. A multifunctional PASHA-electrode® was introduced with trans-sacral access through a hollow needle, placed under fluoroscopic guidance into the lumbosacral epidural space and its active tip moved close to the dorsal root ganglion responsible of the clinical symptoms. After connecting the electrode to a generator, stimulation tests were performed and PRF was started and applied for 240 seconds at a frequency of 2Hz, amplitude of 45 V and a tip temperature between 40 – 42°C. If the pain involved more than a single nerve root, the electrode was placed at a different segment and the procedure repeated. Outcome measures included the pain intensity score on a 0 – 10 numeric rating scale (NRS) and the Italian Pain Questionnaire (QUID) at pre-treatment, one and 6 months post-treatment. P values < 0.05 were considered statistically significant. Results: In comparison with pre-treatment, a significant reduction in pain score was observed in mean NRS either at one and 6 months (P < 0.001). The QUID - Pain Rating Index rank displayed a parallel trend at the first (P < 0.001) and last follow-up (P = 0.01). Moreover, a direct correlation between the 2 scales occurred, showing a parallel score decreasing (P < 0.001). Eighteen (52.9%) and 17 (50%) of 34 patients showed pain reduction in NRS > 2 points and > 30%, at one and 6 months, respectively. Limitations: The non-controlled design of the study, the patients were heterogeneous, the small number of patients, and the duration of follow-up was limited to 6 months. Conclusions: PRF of dorsal root ganglion performed with a multifunctional electrode for > 240 seconds appears to be safe and might be more effective than the classic 120 seconds needlemediated approach. Therefore, it may be considered as a valuable tool for the treatment of lumbosacral radicular pain with neuropathic features. Key words: PRF, radicular pain, neuropathic pain, DRG, NRS, PRIr-T, multifunctional electrode

Effect of extracorporeal shock wave therapy on gait pattern in hemiplegic cerebral palsy: a randomized controlled trial.

The aim of this study was to investigate the effects of shock wave therapy on gait pattern in children with hemiplegic cerebral palsy. Fifteen children were assigned to the study group, whose members received shock wave therapy (1500 shots/muscle, frequency of 5Hz, energy of 0.030 mJ/mm, one session/wk). Another 15 were assigned to the control group, whose members participated in a conventional physical therapy exercise program for 3 successive months. Baseline and posttreatment assessments were performed using the Modified Ashworth Scale to evaluate spasticity degrees and using a three-dimensional gait analysis to evaluate gait parameters. Children in the study group showed a significant improvement when compared with those in the control group (P < 0.005). The Modified Ashworth scores after treatment were 1.86 (0.22) and 1.63 (0.23) for the control and study groups, respectively. The gait parameters (stride length, cadence, speed, cycle time, and stance phase percentage) after treatment were 0.5 m, 125 steps/min, 0.6 m/sec, 0.48 sec, and 50.4% and 0.74 m, 119 steps/min, 0.75 m/sec, 0.65 sec, and 55.9% for the control group and the study group, respectively. Shock wave therapy may be a useful tool for improving spasticity and gait pattern in children with hemiplegic cerebral palsy.

Tratamento com radiofrequência pulsada para gânglio esfenopalatino em pacientes com dor crônica de face e cabeça

PurposeThere are various facial pain syndromes including trigeminal neuralgia, trigeminal neuropathic pain and atypical facial pain syndromes. Effectiveness of the pulsed radiofrequency in managing various pain syndromes has been clearly demonstrated. There are a limited number of studies on the pulsed radiofrequency treatment for sphenopalatine ganglion in patients suffering from face and head pain. The purpose of this study is to evaluate the satisfaction of pulsed radiofrequency treatment at our patients retrospectively. MethodsInfrazygomatic approach was used for the pulsed radiofrequency of the sphenopalatine ganglion under fluoroscopic guidance. After the tip of the needle reached the target point, 0.25‐0.5ms pulse width was applied for sensory stimulation at frequencies from 50Hz to 1V. Paraesthesias were exposed at the roof of the nose at 0.5–0.7V. To rule out trigeminal contact that led to rhythmic mandibular contraction, motor stimulation at a frequency of 2Hz was applied. Then, four cycles of pulsed radiofrequency lesioning were performed for 120s at a temperature of 42°C. ResultsPain relief could not be achieved in 23% of the patients (unacceptable), whereas pain was completely relieved in 35% of the patients (excellent) and mild to moderate pain relief could be achieved in 42% of the patients (good) through sphenopalatine ganglion‐pulsed radiofrequency treatment. ConclusionPulsed radiofrequency of the sphenopalatine ganglion is effective in treating the patients suffering from intractable chronic facial and head pain as shown by our findings. There is a need for prospective, randomized, controlled trials in order to confirm the efficacy and safety of this new treatment modality in chronic head and face pain.

Corticokinematic coherence mainly reflects movement-induced proprioceptive feedback

Corticokinematic coherence (CKC) reflects coupling between magnetoencephalographic (MEG) signals and hand kinematics, mainly occurring at hand movement frequency (F0) and its first harmonic (F1). Since CKC can be obtained for both active and passive movements, it has been suggested to mainly reflect proprioceptive feedback to the primary sensorimotor (SM1) cortex. However, the directionality of the brain–kinematics coupling has not been previously assessed and was thus quantified in the present study by means of renormalized partial directed coherence (rPDC).MEG data were obtained from 15 subjects who performed right index-finger movements and whose finger was, in another session, passively moved, with or without tactile input. Four additional subjects underwent the same task with slowly varying movement pace, spanning the 1–5Hz frequency range. The coupling between SM1 activity recorded with MEG and finger kinematics was assessed with coherence and rPDC.In all conditions, the afferent rPDC spectrum, which resembled the coherence spectrum, displayed higher values than the efferent rPDC spectrum. The afferent rPDC was 37% higher when tactile input was present, and it was at highest at F1 of the passive conditions; the efferent rPDC level did not differ between conditions. The apparent latency for the afferent input, estimated within the framework of the rPDC analysis, was 50–100ms.The higher directional coupling between hand kinematics and SM1 activity in afferent than efferent direction strongly supports the view that CKC mainly reflects movement-related somatosensory proprioceptive afferent input to the contralateral SM1 cortex.

A robust index of lexical representation in the left occipito-temporal cortex as evidenced by EEG responses to fast periodic visual stimulation

Despite decades of research on reading, including the relatively recent contributions of neuroimaging and electrophysiology, identifying selective representations of whole visual words (in contrast to pseudowords) in the human brain remains challenging, in particular without an explicit linguistic task. Here we measured discrimination responses to written words by means of electroencephalography (EEG) during fast periodic visual stimulation. Sequences of pseudofonts, nonwords, or pseudowords were presented through sinusoidal contrast modulation at a periodic 10Hz frequency rate (F), in which words were interspersed at regular intervals of every fifth item (i.e., F/5, 2Hz). Participants monitored a central cross color change and had no linguistic task to perform. Within only 3min of stimulation, a robust discrimination response for words at 2Hz (and its harmonics, i.e., 4 and 6Hz) was observed in all conditions, located predominantly over the left occipito-temporal cortex. The magnitude of the response was largest for words embedded in pseudofonts, and larger in nonwords than in pseudowords, showing that list context effects classically reported in behavioral lexical decision tasks are due to visual discrimination rather than decisional processes. Remarkably, the oddball response was significant even for the critical words/pseudowords discrimination condition in every individual participant. A second experiment replicated this words/pseudowords discrimination, and showed that this effect is not accounted for by a higher bigram frequency of words than pseudowords. Without any explicit task, our results highlight the potential of an EEG fast periodic visual stimulation approach for understanding the representation of written language. Its development in the scientific community might be valuable to rapidly and objectively measure sensitivity to word processing in different human populations, including neuropsychological patients with dyslexia and other reading difficulties.

Fretting and wear behaviors of Ni/nano-WC composite coatings in dry and wet conditions

The fretting and wear behaviors of Ni/nano-WC composite coatings were studied by considering the effect of fretting frequency of 1Hz during 10,000cycles, at different applied loads in dry or wet conditions. The studies were performed on a ball-on-disk tribometer and the results were compared with pure Ni coating. The nanohardness of pure Ni and Ni/nano-WC composite coatings was tested by nanoindentation technique. To evaluate the wet wear (tribocorrosion) behavior the open circuit potential (OCP) was measured before, during and after the fretting tests at room temperature in the solution that simulates the primary water circuit of Pressurized Water Reactors (PWRs). The results show that Ni/nano-WC composite coatings exhibited a low friction coefficient, high nanohardness and wear resistance compared with pure Ni coatings under similar experimental conditions. Ni/nano-WC composite coatings were obtained on stainless steel support by electrochemical codeposition of nano-sized WC particles (diameter size of ∼60nm) with nickel, from a standard nickel Watts plating bath. The surface morphology and the composition of the coatings were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX) respectively.

Development of a high-power solid-state switch using static induction thyristors for a klystron modulator

We developed a solid-state switch with static induction thyristors for the klystron modulator of the L-band electron linear accelerator (linac) at the Institute of Scientific and Industrial Research, Osaka University. This switch is designed to have maximum specifications of a holding voltage of 25kV and a current of 6kA at the repetition frequency of 10Hz for forced air cooling. The turn-on time of the switch was measured with a matched resistor to be 270ns, which is sufficiently fast for the klystron modulator. The switch is retrofitted in the modulator to generate 1.3GHz RF pulses with durations of either 4 or 8μs using a 30MW klystron, and the linac is successfully operated under maximum conditions. This finding demonstrates that the switch can be used as a high-power switch for the modulator. Pulse-to-pulse variations of the klystron voltage are measured to be less than 0.015%, and those of RF power and phase are lower than 0.15% and 0.1°, respectively. These values are significantly smaller than those obtained with a thyratron; hence, the stability of the main RF system is improved. The solid-state switch has been used in normal operation of the linac for more than a year without any serious trouble. Thus, we confirmed the switch’s robustness and long-term reliability.

High-temperature mechanical properties of thermal barrier coated SiC/SiC composites by PIP process with a new precursor polymer

Three dimensional (3D) braided silicon carbide (SiC) fiber reinforced SiC matrix (SiC/SiC) composites were fabricated by precursor impregnation and pyrolysis (PIP) process. Liquid polyvinylcarbosilane (LPVCS) with active SiH and –CHCH2 groups was adopted as the SiC matrix precursor. SiC/SiC composites were coated with environmental barrier coatings (EBCs) to enhance their durability and air oxidation resistance at high temperature. The fabricated SiC/SiC composites exhibited superior density and high-temperature mechanical properties. Bulk density and porosity of the composites were 2.16g/cm3 and 6.7%, respectively. The tensile strength of the composites was 339.7MPa at 1300°C. Tension–tension fatigue tests were conducted at frequency of 1Hz ranging from 40 to 120MPa at 1300°C in air. Fatigue life could be divided into four regimes, low cycle regime, stable-state regime, high cycle regime and run-out regime. The microstructure as well as damage and failure mechanisms of the composites were investigated.

Sphenopalatine ganglion pulsed radiofrequency treatment in patients suffering from chronic face and head pain

PurposeThere are various facial pain syndromes including trigeminal neuralgia, trigeminal neuropathic pain and atypical facial pain syndromes. Effectiveness of the pulsed radiofrequency in managing various pain syndromes has been clearly demonstrated. There are a limited number of studies on the pulsed radiofrequency treatment for sphenopalatine ganglion in patients suffering from face and head pain. The purpose of this study is to evaluate the satisfaction of pulsed radiofrequency treatment at our patients retrospectively. MethodsInfrazygomatic approach was used for the pulsed radiofrequency of the sphenopalatine ganglion under fluoroscopic guidance. After the tip of the needle reached the target point, 0.25–0.5ms pulse width was applied for sensory stimulation at frequencies from 50Hz to 1V. Paraesthesias were exposed at the roof of the nose at 0.5–0.7V. To rule out trigeminal contact that led to rhythmic mandibular contraction, motor stimulation at a frequency of 2Hz was applied. Then, four cycles of pulsed radiofrequency lesioning were performed for 120s at a temperature of 42°C. ResultsPain relief could not be achieved in 23% of the patients (unacceptable), whereas pain was completely relieved in 35% of the patients (excellent) and mild to moderate pain relief could be achieved in 42% of the patients (good) through sphenopalatine ganglion-pulsed radiofrequency treatment. ConclusionPulsed radiofrequency of the sphenopalatine ganglion is effective in treating the patients suffering from intractable chronic facial and head pain as shown by our findings. There is a need for prospective, randomized, controlled trials in order to confirm the efficacy and safety of this new treatment modality in chronic head and face pain.

Noise mechanisms investigation in pyroelectric infrared detectors based on Mn-doped Pb(Mg1/3Nb2/3)O3–0.27PbTiO3 vs. LiTaO3 single crystals

Different noise mechanisms between Mn-doped Pb(Mg1/3Nb2/3)O3–0.27PbTiO3 (Mn-PMNT) and LiTaO3 (LT) based pyroelectric infrared detectors were observed under voltage mode, revealing that at low frequency of 10Hz, dielectric loss noise dominates for Mn-PMNT based detectors, while resistance noise for LT based ones. Meanwhile, an extremely low equivalent voltage noise of appropriate 20nV/Hz1/2 was obtained in Mn-PMNT based detectors, 1/4 times lower than that of the LT based detectors. On the basis of the different noise mechanisms, frequency dependence of figure of merit for detectivity (Fd) have been deduced, providing significant reference values for the analysis of different materials based pyroelectric detectors.

Electron beam charge measurement on PHIL photo-injector using a microcontroller based system

PHIL [1] is an electron beam accelerator at LAL. It produces low energy (E < 5 MeV) and high current (maximum 2nC/bunch, 10 ps duration) electron bunch at a repetition frequency of 5Hz. The beam charge measurements are performed by two Faraday Cups (FC) at both ends of the beam line and also with two Integrating Current Transformer (ICT), installed immediately after the RF gun and at the end of the straight beam line (see figure 1).Extracted signals from the ICT and FC, are processed by electronic circuits, displayed on an oscilloscope, and used to calculate the beam charge manually using the oscilloscope features. This operation is not accurate, does't permit to follow and save the temporal evolution of the charge and cannot be integrated in the control command system. To overcome this problem, a new approach was adopted, based on two systems:An electronic back-end to integrate the signal from coming the charge measurement systems (20ns large pulse), and outputs a large duration signal (around 400μs) whose amplitude is proportional to the beam charge.A microcontroller is used to acquire the integrated signal with a repetition rate of 5Hz, make the analog-digital conversion, and calculate the mean beam charge.The output signal can be sent to the control command system for displaying and to automate other process, especially the measurements of the beam charge versus RF/Laser phase. This system offers good accuracy, with a resolution of around 1pC, and can be easily integrated in the control command system.

Recurrence Characteristics Analysis of Near-Surface Wind Speed Signal with Different Sampling Frequencies

The wind is the main factor to influence the propagation of gas in the atmosphere. Therefore, the wind signal obtained by anemometer will provide us valuable clues for searching gas leakage sources. In this paper, the Recurrence Plot (RP) and Recurrence Quantification Analysis (RQA) are applied to analyze the influence of recurrence characteristics of the wind speed time series under the condition of the same place, the same time period and with the sampling frequency of 1hz, 2hz, 4.2hz, 5hz, 8.3hz, 12.5hz and 16.7hz respectively. Research results show that when the sampling frequency is higher than 5hz, the trends of recurrence nature of different groups are basically unchanged. However, when the sampling frequency is set below 5hz, the original trend of recurrence nature is destroyed, because the recurrence characteristic curves obtained using different sampling frequencies appear cross or overlapping phenomena. The above results indicate that the anemometer will not be able to fully capture the detailed information in wind field when its sampling frequency is lower than 5hz. The recurrence characteristics analysis of the wind speed signals provides an important basis for the optimal selection of anemometer.

The application of impulse oscillation system for the evaluation of treatment effects in patients with COPD

There are only a few reports of the use of impulse oscillation system (IOS) for the evaluation of COPD treatment. In this study, we applied IOS and spirometry to evaluate the effectiveness of fluticasone propionate and salmeterol (SFC) combined with tiotropium (TIO) in COPD patients. Following a 4-week run-in period with TIO (18μg once daily) treatment, COPD patients were randomized to SFC (250/50μg twice daily; SFC+TIO group, n=25), or TIO alone (TIO group, n=31). Pulmonary functions were recorded by IOS and spirometry before and after the study period. The SFC+TIO group showed significant improvements in inspiratory resistance at 5Hz and resonant frequency, as well as in FVC and FEV1, after the 12-week treatment (p<0.05). Since there were no significant correlations between improvements in IOS measurements and FVC or FEV1, IOS may provide a physiological point of view that is different from spirometry and seemed to be applicable as an additional assessment tool targeting COPD patients.

Dynamic soil–structure interaction analysis of a telescope at the Javalambre Astrophysical Observatory

This paper presents the dynamic soil–structure analysis of the main telescope T250 of the Observatorio Astrofísico de Javalambre (OAJ, Javalambre Astrophysical Observatory) on the Pico del Buitre. Vibration control has been of prime concern in the design, since astrophysical observations may be hindered by mechanical vibration of optical equipment due to wind loading. The telescope manufacturer therefore has imposed a minimal natural frequency of 10Hz for the supporting telescope pier. Dynamic soil–structure interaction may significantly influence the lowest natural frequency of a massive construction as a telescope pier. The structure clamped at its base has a resonance frequency of 14.3Hz. A coupled finite element–boundary element (FE–BE) model of the telescope pier that accounts for the dynamic interaction of the piled foundation and the soil predicts a resonance frequency of 11.2Hz, demonstrating the significant effect of dynamic soil–structure interaction. It is further investigated to what extent the coupled FE–BE model can be simplified in order to reduce computation time. The assumption of a rigid pile cap allows us to account for dynamic soil–structure interaction in a simplified way. A coupled FE–BE analysis with a rigid pile cap predicts a resonance frequency of 11.7Hz, demonstrating a minor effect of the pile cap flexibility on the resonance frequency of the telescope pier. The use of an analytical model for the pile group results in an overestimation of the dynamic soil stiffness. This error is due to the large difference between the actual geometry and the square pile cap model for which the parameters have been tuned.

Effect of non-plastic silt content on the liquefaction behavior of sand–silt mixture

To identify the effect of non-plastic silt on the cyclic behavior of sand–silt mixtures, total sixty undrained cyclic triaxial stress-control tests were carried out on sand–silt mixtures. These tests were conducted on specimens of size 71mm diameter and 142mm height with a frequency of 1Hz. Specimens were prepared at a constant relative density and constant density approach. The effect of relative density, confining pressure as well as magnitude of cyclic loading was also studied. For a constant relative density (Dr=60%) the effect of limiting silt content, pore pressure response and cyclic strength was observed. The rate of generation of excess pore water pressure with respect to cycles of loading was found to initially increase with increase in silt content till the limiting silt content and thereafter it reverses its trend when the specimens were tested at a constant relative density. The cyclic resistance behavior was observed to be just opposite to the pore pressure response. Permeability, CRR and secant shear modulus decreased till limiting silt content; after that they became constant with increasing silt content.

Neural pathway prediction based on multi-neuron spike train data

The finding of Neural Pathway is typically based on brain slicing and reconstruction with nanoscale imaging. Nevertheless, this method is not applicable when nanoscale imaging is not available. We propose that multineuron spike train data can be used as an alternative source to predict the neural pathways, and here we discuss two concrete strategies for neural pathway prediction based on this kind of data. Multi-neuron spike train data is composed of spike trains from multiple neurons recorded in the same time interval. The data typically shows whether a specific neuron generates a spike or not at a specific time. Two strategies are proposed for neural pathway prediction: (1) The time-ordered strategy: Synapses exist between neurons that generate spikes at the two neighborhood time points (the time point N and N-1). (2) The spike co-occurrence strategy: Synapses exist between neurons that fire together at the same time point. This strategy is consistent with the Hebb’ sl aw“Cells that fire together, wire together”. Data of the rat hippocampus CA3 pyramidal cell layer based on functional Multineuron Calcium Imaging (fMCI) is used for neural pathway prediction (Including 8 datasets, and each of them records spike activities for 62 to 226 neurons. The datasets were imaged with the frequency of 10Hz [1,2]) using the upper two proposed strategies. We validate the accuracy of the neural pathway prediction strategies based on the following steps. The overall prediction accuracy is an average value based on the 8 dataset. For each of the dataset: (1) Equally divide one dataset as 20 sub datasets according to the time intervals (The sub datasets are denoted as S1,…,S20). Select the first 80% of the sub datasets (S1,…,S16 )f or neural pathway construction, and validate the pathway using the rest of the 20% sub dataset (Here we assume that if the predicted pathway is correct, it should cover the neuronal connections based on the rest of the 20% sub dataset). (2) Select another 80% of the sub datasets for neural pathway construction, and the rest for validation, and repeat this step until all the sub datasets have been selected for validation. (3) The prediction accuracy is the average value of the 20 predictions. There are several important observations and indications based on the prediction results. (1) Although the two prediction strategies seem entirely different, the neural pathways based on the two different strategies are very relevant (The correlation is significant with the Pearson correlation value 0.958). It indicates that although the proposed strategies are different, the results from the different two strategies do not have major conflicts, instead they are very consistent, and support each other. (2) The neural pathway prediction accuracy for the time-ordered strategy is 83%, and the accuracy for the spike co-occurrence strategy is 80%. When we group the two neural pathways together (denoted as the merged strategy), the prediction accuracy reaches 89% (Figure 1 shows the prediction accuracy for each of the dataset using the proposed strategies). This result indicates that better prediction can be made when the predicted pathways from the two strategies are combined together. (3) 27% of the possible connections among neurons are selected for the time-ordered strategy, while 25% of the connections are selected by the spike cooccurrence strategy. If the two results are grouped together, 32% of the possible connections are included. The results seem good, since the coverage is not high (and is consistent with the observation by using electromicroscopy techniques [3,4]), while the predicted accuracy for possible neural pathway reaches 89%. The proposed method is validated on the data in which the distance of two neurons is within approximately 400um [5]. Whether the proposal is applicable

Distributed vibration/acoustic sensing with high frequency response and spatial resolution based on time-division multiplexing

A novel time-division multiplexing scheme is proposed and demonstrated for distributed vibration/acoustic sensing with broad frequency response range and high spatial resolution. By setting the time delay between a narrow pulse and a quasi-continuous wave properly, conventional phase optical time-domain reflectometry and polarization diversity scheme can be combined without crosstalk to determine position and frequency of vibration event, respectively. Detections of high vibration frequency of 0.6MHz and low frequency of 1Hz are presented with 1m spatial resolution over 680m single-mode sensing fiber.

Alpha–theta border EEG abnormalities in preclinical Huntington's disease

BackgroundBrain dysfunction precedes clinical manifestation of Huntington's disease (HD) by decades. This study was aimed to determine whether resting EEG is altered in preclinical HD mutations carriers (pre-HD). MethodsWe examined relative power of broad traditional EEG bands as well as 1-Hz sub-bands of theta and alpha from the resting-state EEG of 29 pre-HD individuals and of 29 age-matched normal controls. ResultsThe relative power of the narrow sub-band in the border of theta–alpha (7–8Hz) was significantly reduced in pre-HD subjects as compared to normal controls, while the alterations in relative power of the broad frequency bands were not significant. In pre-HD subjects, the number of CAG repeats in the huntingtin (HTT) gene as well as the disease burden score (DBS) showed a positive correlation with relative power of the delta and theta frequency bands and their sub-bands and a negative correlation with alpha band relative power and the differences of relative power of the 7–8Hz and 4–5Hz frequency sub-bands. ConclusionThe obtained results suggest that EEG alterations in pre-HD individuals may be related to the course of the pathological process and to HD endophenotype. Analysis of the narrow EEG bands was found to be more useful for assessing EEG alterations in pre-HD individuals than a more traditional approach using broad bandwidths.