Low Frequency Ratio Research Articles

Adjunctive Therapeutic Effects of Cinnamomum Camphora Forest Environment on Elderly Patients with Hypertension

Background: Many studies have demonstrated the beneficial effects of the mixed forest environment on human health. However, few studied the effect of the single tree species forest on human health. This study was explored the effect of C. camphora forest environment on elderly patients with hypertension (HTN). Methods: 31 elderly patients with essential HTN were randomly divided into two groups. Blood pressure (BP), pulse oxygen saturation (SpO_2%), heart rate (HR), heart rate variability (HRV) and levels of plasma high-sensitivity C-reactive protein (hs-CRP), as well as profile of mood states (POMS) test, were measured. Environment factors of two experimental sites were monitored. Categorical variables and continuous data were analyzed by Chi-square and t-test, respectively. Results: After forest bathing, subjects in the forest group showed significantly lower levels of diastolic blood pressure (DBP), low frequency (LF), the ratio of low frequency and high frequency (LF/HF) and hs-CRP, and greatly higher levels of SpO_2% and high frequency (HF) than that of in control group. Furthermore, negative mood subscale scores of POMS were significantly lower following forest bathing, while the positive score was much higher. However, the main components of volatile organic compounds (VOCs) in the two experimental sites were obviously different. Conclusion: C. Camphora environment significantly decreased the DBP and inflammatory level, balanced the autonomic activity and improved the mood state of participates, which might be associated with the biological effectiveness of terpenes, implying that C. Camphora environment might be an adjunctive therapy for HTN patients.

The Impact of Remote Ischaemic Conditioning on Beat-to-Beat Heart Rate Variability Circadian Rhythm in Healthy Adults

Remote ischaemic conditioning (RIC) is an intervention that may exert a protective effect over multiple tissues or organs by regulating neuronal signal transduction. Heart rate variability (HRV) can assess the state of the autonomic nervous system. However, whether RIC can also regulate HRV in humans remains unknown. This was a self-controlled interventional study in which serial beat-to-beat monitoring was performed at the same seven time points (7, 9, and 11 AM; 2, 5, and 8 PM; and 8 AM on the next day) with or without RIC in 50 healthy adults. The seven time points on the RIC day were defined as baseline, 1 hour, 3 hours, 6 hours, 9hours, 12 hours, and 24 hours after RIC. The RIC protocol consisted of 4×5-minute inflation/deflation in one arm and one thigh cuff at 200 mmHg pressure from 7:20 to 8 AM. This study is registered on ClinicalTrials.gov (NCT02965547). We included 50 healthy adult volunteers (aged 34.54±12.01 years, 22 men [44%], all Asian). The variables analysed in frequency-domain measures performed as power of low-frequency in normalised units (0.04-0.15 Hz), high-frequency in normalised units (0.15-0.40 Hz), and ratio of low frequency to high frequency. The time-domain parameters standard deviation (SD) of all normal to normal (NN) intervals (SDNN), mean of the 5-minute SD of the NN intervals, SD of the consecutive 5-minute averages of NN intervals, and the root mean square of successive differences of NN intervals, and time-domain parameters calculated from Poincaré plots, SD of the short diagonal axis in Poincaré plot (SD1), SD of the long diagonal axis in Poincaré plot (SD2), and SD1/SD2 were also obtained. The SDNN and SD2 significantly increased 1 hour after RIC (p=0.029 and p=0.045, respectively). Additionally, the SD2 increased a second time 12 hours after RIC (p=0.041), which represented inhibited sympathetic activity. Heart rate variability increase and sympathetic inhibition induced by RIC appeared both on the early and delayed protective window of RIC, which may indicate some of the underlying mechanisms by which RIC may offer protection.

Spectral Analysis and Sideband Harmonic Cancellation of Six-Step Operation With Low Carrier–Fundamental Frequency Ratio for High-Speed Brushless DC Drives

High-speed brushless dc (BLDC) drives usually operate with low carrier-fundamental frequency ratio, which causes abundant sideband harmonic current components. Some sideband harmonics will be induced in low-frequency range, leading to low-frequency current oscillations and low-frequency torque ripples. To minimize these undesired sideband harmonics, a novel pulsewidth modulation commutation pattern, i.e., carrier-synchronized commutation (CSC), is proposed in this article. For comparison, two conventional commutation patterns, including regular-sampled commutation (RSC), and natural-sampled commutation (NSC), are analyzed. To reveal the characteristics of sideband harmonics caused by RSC and NSC patterns, an extended geometric wall model is introduced, which can be used for the Fourier decomposition of complex vectors. Theoretical, simulation, and experimental results demonstrate the conventional RSC and NSC patterns will produce additional sideband harmonic currents and torque ripples, while the proposed CSC pattern can considerably suppress these adverse influences and meanwhile presents high performance and robustness.

The effect of remote ischemic postconditioning on autonomic function in patients with acute ischemic stroke: A Randomized Controlled Trail

ObjectiveThe evidence for the effect of remote ischemic postconditioning(RIpostC) on autonomic function in patients with acute ischemic stroke(AIS) is lacking and the neural mechanism underlying the protection of RIpostC remains speculative. This trial was aimed to evaluated the efficiency of RIpostC on autonomic function in AIS patients. DesignOne hundred and six AIS patients were included in this prospective, randomized, placebo-controlled trial. Patients in intervention group (n = 57) received 4 cycles of alternating inflation (cuff inflation to 200 mmHg) and deflation for 5 min on healthy upper arm once a day for 30 days. The control group underwent a sham inflation and deflation cycles. Autonomic function was evaluated by heart rate variability (HRV). ResultsAll HRV parameters except for the ratio of low frequency to high frequency (P = 0.101) increased significantly with time (P < 0.001) in the two groups. The value of standard deviation of all normal R-R intervals(SDNN) and high frequency at day7 and day30 and the value of the percent of difference between adjacent normal R-R intervals (pNN50) at day 30 in RIpostC group was significantly higher than that of the sham-RIpostC group(P < 0.05). A significant time-by-group interaction was observed in SDNN、pNN50、and high frequency over time between two groups (P < 0.05). Conclusions30-day RIpostC could improve autonomic function in AIS patients through the enhancement of the total autonomic nerve activity and vagus nerve activity. The mechanism of RIpostC mediating autonomic function needs to be further investigated.

MODULATION OF AUTONOMIC NERVOUS SYSTEM ASSESSED THROUGH HEART RATE VARIABILITY BY INTEGRATED AMRITA MEDITATION TECHNIQUE IN TYPE 2 DIABETIC SUBJECTS – A PILOT STUDY

Objective: This study aims in understanding the effects of Integrated Amrita Meditation (IAM), a type of mindfulness meditation, on the autonomic balance of type 2 diabetic patients through assessment of heart rate variability (HRV).&#x0D; Methods: After the initial screening of 30 type 2 diabetic subjects, 10 type 2 diabetic subjects between the age group of 30 and 65 years were randomized into two groups, diabetic test (n=5) and diabetic control group (n=5). Diabetic test group practiced IAM technique under the guidance of a trained practitioner. Both the groups continued the same dietary pattern and medications during the 6-month study period. HRV was taken for all subjects at baseline and after 6 months. In our study, we have focused on the power spectral analysis of HRV which include normalized units of high frequency (nHF), low frequency (nLF), and low frequency-high frequency ratio (LF/HF ratio).&#x0D; Results: Mean percentage change in nHF, nLF, and LFHF ratio showed significant changes in between-group comparison (p&lt;0.05). Normalized units of HF increased (p=0.049) while LF (p=0.036) and LFHF ratio (p=0.024) decreased significantly within test group after 6 months of IAM practice suggesting the potential of IAM in improving the parasympathetic tone, thereby tuning the mind and body to calm down during stress.&#x0D; Conclusion: Our study has shown demonstrable improvement in autonomic function which reflects reduced stress after the practice of IAM in diabetic patients.

Effects of Types of Horticultural Activity on the Physical and Mental State of Elderly Individuals.

This study aimed to evaluate the effect of types of horticultural activities among elderly individuals in a senior citizen learning camp. We arranged four horticultural activities: Grass Doll, Kokedama, Rocky Leaf Prints, and Herb Tasting and Smelling. Twenty-seven senior citizens (60 to 76 years) were recruited to participate. We assessed their physiological and mental state before and after the activities by measuring heart rate variability (HRV), pulse rate, blood pressure, salivary amylase activity (SAA), and Profile of Mood States (POMS). Results showed that SAA was significantly lower after the Rocky Leaf Prints, Herb Tasting and Smelling, and Kokedama. Pulse rate had a downward trend after the four horticultural activities. The ratio of low frequency (LF) over high frequency (HF) results showed that the Rocky Leaf Prints had a larger downward trend, followed by Herb Tasting and Smelling. POMS scores indicated significant improvement for Rocky Leaf Prints and Herb Tasting and Smelling. The types including artistic creation and food tasting were promising methods for psychological relaxation, stress reduction, and vigor enhancement for elderly persons. Findings showed that the impact of activities involving contact with plants was more significant in short-term activities. We hope this study can help plan the horticultural activities of the elderly in the future.

Effect of Mozart K.448 on interictal epileptiform discharges in children with epilepsy: A randomized controlled pilot study

BackgroundEpilepsy is a common pediatric neurologic disease in Thailand. However, the mainstay antiepileptic pharmacotherapies can induce severe side effects. While the benefit of playing Mozart K.448 music has been studied as an alternative, supplementary, nonpharmacologic treatment for epilepsy, the literature features limited few randomized controlled trial studies of children. ObjectiveWe aimed to study the effect of Mozart K.448 for two pianos on interictal epileptiform discharges (IEDs), quantitative electroencephalogram (qEEG), and heart rate variability (HRV) in patients with epilepsy. MethodsWe employed a single-blinded randomized trial design with a placebo control. The treatment group listened to the first 8 min of Mozart K.448 for two pianos during EEG recording. The control group underwent an EEG recording of the same duration in a quiet environment. Interictal epileptiform discharges were manually counted for 8 min before, during, and after the song was plated. Quantitative electroencephalogram and HRV were analyzed in each period. ResultA total of 32 patients aged 0–18 years were enrolled. There were 12 patients in the music group and 14 patients in the control group; 67% of the patients in the former exhibited significantly decreased IEDs while listening to the music compared with 42% of the patients in the quiet group (RR [Relative Risk Reduction]: 0.72, p-value: <0.001, 95% confidence interval [CI]: 0.69–0.74). During music exposure, qEEG demonstrated an increase in the delta/theta to alpha/beta ratio relative to that of controls (median in music: +3% and control: −6%, p-value: 0.520). Heart rate variability analyses showed a decrease in the ratio of low frequency to high frequency (LF/HF), which represents parasympathetic activity during music exposure (decrease of 34%, p-value: 0.382). ConclusionThe present study showed that Mozart K.448 reduced the number of IEDs in children with epilepsy and that Mozart K.448 could enhance parasympathetic activity. However, possibly because of the small study population, statistical significance was not reached. Our study revealed the considerable potential of music in the treatment of pediatric epilepsy.

Spectral Analysis of Heart Rate Variability During Trigger-Point Acupuncture of Various Muscles.

Objective: The aim of this research was to clarify changes in cardiovascular autonomic nervous system function due to trigger-point (TP) acupuncture; the current author evaluated differences in responses among acupuncture at TPs of various muscles using spectral analysis of heart rate variability. Materials and Methods: Subjects were 48 healthy men. Before measurements began, subjects were assigned to a TP acupuncture or control group based on presence/absence of referred pain on applying pressure to a taut band within the right extensor digitorum muscle, tibialis anterior muscle, gluteus medius muscle, or masseter muscle. Measurements were conducted in a room with a temperature of 25°C, with subjects in a long sitting position after 10 minutes of rest. Acupuncture needles were retained for 10 minutes at 1 site on the right extensor digitorum muscle, tibialis anterior muscle, gluteus medius muscle, or masseter muscle. Electrocardiography was performed simultaneously with respiratory-cycle measurements. Based on the R-R interval on the electrocardiograms, frequency analysis was performed, low-frequency (LF) and high-frequency (HF) components were extracted, and the ratio of LF to HF components (LF/HF) was evaluated. Results: All subjects in the TP acupuncture group showed a transient increase in the HF component, but no significant changes in heart rate (HR) or LF/HF. In the control group, no significant changes were observed in HR, HF component, or LF/HF. Conclusions: These data suggest that acupuncture stimulation of TPs of the right extensor digitorum muscle, tibialis anterior muscle, gluteus medius muscle, and masseter muscle increases parasympathetic nerve activity transiently.

Numerical study of the sound generated by two tandem arranged wings in forward flight

The sound generated by two tandem arranged flexible wings in forward flight is numerically studied by using an immersed boundary method, at a Reynolds number of 100 and Mach number of 0.1. Three distinct cases are studied, encompassing a single wing and two tandem wings flapping in phase and out of phase. The sound generation of flapping wings is systematically studied by varying the wing flexibility (represented by the frequency ratio [Formula: see text]), structure-to-fluid mass ratio ([Formula: see text]), the phase difference (φ), and the gap ([Formula: see text]) between the two flapping wings. The results show that there is a direct correlation between the wing flexibility and sound generation for all cases considered. Specifically, for wings of low mass ratios ([Formula: see text]), an increase in flexibility resulted in a decrease in sound generation. For wings of high mass ratios ([Formula: see text]), an increase in flexibility resulted in higher sound output. The introduction of a second wing flapping in-phase resulted in an increase in aerodynamic features and sound generation, while the introduction of a second wing flapping out-of-phase experiences a decrease in sound output when compared to the in-phase case. In both cases, the effect of the wing flexibility on the sound production is similar to that of the single wing. An increase in flexibility is also found to have an impact on the plane of maximum sound pressure. For example, increasing flexibility resulted in a rotation of the plane of maximum sound pressure counter-clockwise relative to those at lower frequency ratios. Flexible wings with a structure-to-fluid mass ratio of unity and medium flexibility (i.e. [Formula: see text] and [Formula: see text]) are found to generate lower sound with high aerodynamic performance conserved.

Intermuscular coupling based on wavelet packet-cross frequency coherence

Human motion control system has a high degree of nonlinear characteristics. Through quantitative evaluation of the nonlinear coupling strength between surface electromyogram (sEMG) signals, we can get the functional state of the muscles related to the movement, and then explore the mechanism of human motion control. In this paper, wavelet packet decomposition and n: m coherence analysis are combined to construct an intermuscular cross-frequency coupling analysis model based on wavelet packet- n: m coherence. In the elbow flexion and extension state with 30% maximum voluntary contraction force (MVC), sEMG signals of 20 healthy adults were collected. Firstly, the subband components were obtained based on wavelet packet decomposition, and then the n: m coherence of subband signals was calculated to analyze the coupling characteristics between muscles. The results show that the linear coupling strength (frequency ratio 1:1) of the cooperative and antagonistic pairs is higher than that of the nonlinear coupling (frequency ratio 1:2, 2:1 and 1:3, 3:1) under the elbow flexion motion of 30% MVC; the coupling strength decreases with the increase of frequency ratio for the intermuscular nonlinear coupling, and there is no significant difference between the frequency ratio n: m and m: n. The intermuscular coupling in beta and gamma bands is mainly reflected in the linear coupling (1:1), nonlinear coupling of low frequency ratio (1:2, 2:1) between synergetic pair and the linear coupling between antagonistic pairs. The results show that the wavelet packet- n: m coherence method can qualitatively describe the nonlinear coupling strength between muscles, which provides a theoretical reference for further revealing the mechanism of human motion control and the rehabilitation evaluation of patients with motor dysfunction.

CDK5 promotes ventricular arrhythmogenesis through phosphorylation of N‐type calcium channels in cardiac sympathetic postganglionic neurons

Cardiac sympathetic overactivation is an important trigger of fatal ventricular arrhythmias in patients with chronic heart failure (CHF). Our previous study found that increased N‐type calcium (Cav2.2) currents in cardiac sympathetic postganglionic (CSP) neurons contributes to cardiac sympathetic overactivation and ventricular arrhythmogenesis in CHF rats. Cyclin‐dependent kinase 5 (CDK5), a proline‐directed serine/threonine kinase, has been reported to play an important role in regulation of calcium influx and neurotransmitter release through phosphorylation of Cav2.2α subunit. Our current study aims to investigate whether CDK5 induces cardiac sympathetic overactivation and increases the susceptibility to ventricular arrhythmias via phosphorylation of Cav2.2α in CSP neurons. Lentiviral‐CDK5 cDNA (1×107 TU/ml, 2μl) was in vivo transfected into bilateral stellate ganglia (SG) in sham rats. Nontransfected sham rats served as controls. Final experiments were performed at 9 days after gene transfection. Western blot data demonstrated that gene transfection with lentiviral‐CDK5 cDNA into SGs significantly increased protein expression of CDK5 in CSP neurons in sham rats, compared with nontransfected sham rats. CDK5 cDNA transfection in SGs increased phosphorylation level of Cav 2.2α in CSP neurons from sham rat. The power spectral analysis of heart rate variability in conscious rats demonstrated that overexpression of CDK5 in CSP neurons increased low frequency power and ratio of low frequency to high frequency (index of cardiac sympathetic activation). Additionally, transfection of CDK5 cDNA into CSP neurons markedly increased cardiac sympathetic nerve activity in anesthetized sham rats (45.3±6.4% in sham+CDK5 group vs. 29.2±2.1% in sham group). ECG data obtained from 24‐hour continuous telemetry ECG recording revealed that overexpression of CDK5 in CSP neurons induced heterogeneity of ventricular electrical activities in conscious sham rats, as evidenced by CDK5 cDNA‐elongated ventricular arrhythmia‐related ECG markers including QT interval, QT dispersion, and T‐peak to T‐end interval. More importantly, transfection with CDK5 cDNA into CSP neurons significantly increased the susceptibility to ventricular arrhythmias (arrhythmia score was 1.7±0.9 in sham+CDK5 group vs. 0 in sham group) in anesthetized sham rats. Based on above data, we conclude that CDK5 induces cardiac sympathetic overactivation via phosphorylation of Cav 2.2‐α subunits in CSP neurons, and further increases the susceptibility of ventricular arrhythmias in sham rats.Support or Funding InformationThis study was supported by National Heart, Lung, and Blood Institute Grant (R01HL137832‐01 to Y.‐L. Li)

Measures of Heart‐Rate Variability Immediately Post Concussion

There 1.6 to 3.8 million sports‐related concussions reported annually. Despite the growing number of sports‐related concussions, there is a lack of evidence‐based methods to evaluate, treat, predict, and monitor recovery in affected athletes. The pathophysiology undermining the changes in the brain post injury remains unknown. Increasing studies have shown there is autonomic nervous system (ANS) dysfunction following brain injury. Heart rate variability can be used as a method to measure autonomic nervous system anomalies to aid in the detection of concussions. To obtain this data we have developed a mobile tent‐based laboratory that allows us to gather data on the field during a rugby match. Data were collected acutely post‐injury to provide a rapid assessment of concussion effects on the cerebrovascular physiology. The conditions are that athletes all played in a rugby match before enrolling in the study. If the athlete experienced an injury, they had to be assessed by a medical team who classified them as having a concussion. If they did not require any further medical treatment, they were given the option to participate in our study. To assess the autonomic effects of concussion we measured beat‐by‐beat blood pressure (Finometer), heart rate, common and internal carotid blood flow, and end‐tidal CO2 using a nasal cannula during rest, both in the seated and supine position. In a subgroup of 15 players collected last August (6 controls, 9 concussed, Mean age= 30, range= 19–66 yrs) out of our large study (195 players (88 with concussions) we had players perform a SCAT total number of symptoms as well as Symptom Severity Score. Concussed players had significantly higher SCAT total number of symptoms (8 ± 3 vs 4 ± 3, P=0.04) and trending towards a higher Symptom Severity Score (23± 14 vs 10 ± 9, P=0.08). Mean RR Interval in concussed players (seated: 685 ± 41 vs supine: 720 ± 61 ms) compared to controls (seated: 734 ± 90 vs supine: 786 ± 90 ms). Examining postural changes in heart rate variability we found that concussed players demonstrated significant changes in the Low Frequency (LF) ratio seated/supine (Concussed: 1.09 ± 0.47 v Controls: 0.46 ± 0.16) and no change in the High Frequency (HF) ratio seated/supine (Concussed: 0.61 ± 0.21 vs Controls: 0.77 ± 0.29, P=0.3). The SCAT total number of symptoms was significantly correlated to ratio of seated/supine in the LF range in concussed players (r=0.71, P=0.03) but not the HF ratio (r=.48, P=.18). This subset of data suggests that there are changes in heart rate variability immediately post‐concussion, which may be correlated with the number of symptoms following a hit to the head. This data also supports that measures are dependent on posture. The LF frequency increases in the seated position in concussed players suggesting an increase in sympathetic activity, compared to decreasing in controls. Future work is needed to examine how immediate measures of heart rate and brain blood flow in seated and supine are predictive of concussion outcomes.Support or Funding InformationThis work was supported by Dept. of Pharmacology, Physiology, and Neuroscience, Rutgers.

Effects of electrical parameters and their interactions on plasma electrolytic oxidation coatings on aluminum substrates

Based on orthogonal experiments, the effects of voltage, frequency, duty ratio and their interactions on the thickness and corrosion resistance of coatings prepared by plasma electrolytic oxidation (PEO) on aluminum in an alkaline silicate-containing electrolyte were investigated. The thicknesses of these coatings were obtained by measuring their cross-section using Image J software. Their corrosion resistances were evaluated in HCl and NaCl media through spot test and electrochemical test. The results show that the experimental design of this study is the key to investigate the interactions among these electrical parameters. Additionally, not only each independent factor, but also their interactions exhibit a remarkable influence on the coatings. The combination of high voltage, low frequency and large duty ratio significantly increases the coating thickness and content of the corrosion resistance phase, and thus improves the corrosion resistance of the coating in HNO 3 medium. Conversely, the coating possessing the densest microstructure and best corrosion resistance in NaCl medium is obtained when low voltage and high frequency match with a small duty ratio.

Analysis and Suppression of the Frequency-Decrease Effect in the Capacitor Voltage Related to the Low Modulation Frequency Ratio in an MMC System

The carrier phase-shift pulsewidth modulation (PWM) strategy is widely used in modular multilevel converters (MMCs), where the modulation frequency ratio of switching and fundamental frequency is a major parameter. However, a low modulation frequency ratio, which is often implemented to decrease the power loss in a high-power MMC system, can greatly decrease the harmonic frequencies of the submodules' capacitor voltages. Such effect is defined as the frequency-decrease effect in the capacitor voltage, which can cause several severe deteriorations, such as the low-frequency fluctuations, the unstable charge-discharge state of submodules' capacitors, and unbalance phenomenon of the capacitor voltages, thus significantly deteriorating the system working performance. This study first proposes the mechanism of the frequency-decrease effect. A quantitative analysis of the relations between the frequency-decrease effect, the modulation frequency ratio, and corresponding deteriorations is then provided, indicating the root cause of the frequency-decrease effect. Based on the analysis, an appropriate enhanced balance strategy is introduced into the system. An optimal design method is used to determine an appropriate modulation frequency ratio and to mitigate the frequency-decrease effect; and an improved balancing method, which combines the direct-bias injection and condition selection to determine the modulation wave, is used to further improve the system performance. The frequency-decrease effect, the corresponding deteriorations, and the efficiency of the enhanced balance strategy to suppress the frequency-decrease effect are finally demonstrated via simulations and experiments.

Spectral Analysis of Heart Rate Variability During Mobile Phone Usage in First Year Medical Students

Background: The electromagnetic radiations emitted by cellular telephones may influence the autonomic tone which modifies the functioning of the circulatory system. Aim and Objectives: To estimate the effect of using mobile phones on heart rate variability (HRV) in first year medical students. Method: ECG and HRV parameters are recorded in three periods, - when the subject is at rest without mobile phone (Period-I), with mobile phone kept on the left chest (Period-II) and when responding to a call by keeping the mobile over his right ear (Period-III) on 100 healthy subjects aged between 18 and 21 years of either sex.Results:When the mobile was kept on chest or while attending a call,a decrease in high frequency (HF) in normalized units and increase in low frequency (LF) in normalized units and increase in the ratio of LF to HF (LF/HF) was observed in the frequency domain measures. Decrease in RR intervals, RMSSD and NN50 was observed in the time domain measures . Conclusion: The participants showed a higher sympathetic tone and a lower parasympathetic tone while attending a call. The study proved the intense effects of handset radiofrequency radiations on autonomic balance in healthy subjects.

Dual-Band Frequency Selective Surface With Compact Dimension and Low Frequency Ratio

In this paper, frequency selective surface (FSS) with low profile, miniaturized structure and closely located dual-band is proposed based on the fractal technology. The FSS is designed by etching the conductive pattern on a single layer substrate. Two fractal slots are designed to increase the spatial efficiency of the pattern and provide two isolated resonances. For the dual-band FSS, the miniaturization should work for both of the resonances to keep the frequency ratio. Therefore, the slots are convoluted as different principles and twisted with each other to keep the miniaturization and isolation. With the third-order fractal pattern, two pass-bands are achieved at 1.04 GHz and 1.49 GHz with the frequency ratio of 1.42. The dimension of the element is as compact as 0.039λ× 0.039λ where λ is the wavelength of low frequency resonance. Moreover, benefiting from the miniaturized element, the angular stability is very good that the resonances keep stable when the incident angle increasing from 0° to 60°. In order to get insight of the mechanism of the proposed element, an equivalent circuit model is established and studied. A prototype is fabricated and all the proposed performances are verified by simulations and measurements.

Examining the Relation between Heart Rate Variability, Flow, and Shooting in Wheelchair Athletes

PURPOSE: Heart rate variability leads affective changes, which are associated with athletic performance. This study aimed to examine the relationship between heart rate variability, athletic flow, and shooting performance in wheelchair shooting athletes. METHODS: Eight male and female wheelchair shooting athletes were participated in the study. Heart rate variability was measured at rest and during shooting practice and competitions. Flow experience and shooting score were collected only during practice and actual shooting. SPSS Windows 25.0 was used to perform the following analysis. A repeated one-way ANOVA was applied to analyze the dif ferences in heart rate variability at rest, during practice and actual shooting. In order to see the linear and curvilinear relationship among the variables, a hierarchical regression analysis was conducted. RESULTS: The level of average heart rate and the ratio of Low Frequency (LF) to High Frequency (HF) of heart rate variability were significantly at different situations. At the resting period average heart rate was the highest while LF/HF was the lowest, which indicated that LF was less activated than HF at rest as compared to actual shooting. A hierarchical regression analysis showed that flow was a sig nificant linear predictor for shooting performance. CONCLUSIONS: Heart rate variability is changing depending on the circumstance that athletes faced to, which suggests that the changes may be associated with psychological states and performance.

Cardiac Autonomic Activity in Commercial Aircrew During an Actual Flight Duty Period.

BACKGROUND: The work schedules of airline crewmembers include extended workdays, compressed work periods, and limited time for recovery, which may lead to cardiovascular strain and fatigue. The aim of this study was to evaluate changes in heart rate variability (HRV) during work and sleep, and with respect to work characteristics and breaks.METHODS: We followed 49 airline crewmembers during four consecutive workdays of ≥39 h. Data included HRV measurements, a questionnaire, and sleep/work diaries. HRV parameters include root mean square of successive differences (RMSSD), standard deviation of the normal beat-to-beat differences (SDNN), and the low and high frequency ratio (LF/HF).RESULTS: The results indicate higher levels of cardiovascular strain on the 4th compared to the 1st workday, most prominent among cabin crewmembers. In this group, we observed indications of decreased cardiovascular strain by increasing duration of sleep, demonstrated by increased RMSSD (B = 2.7, 95% CI 1.6, 3.8) and SDNN (B = 4.4, 95% CI 3.0, 5.7), and decreased LF/HF (B = -0.2, 95% CI, -0.4,-0.01). Similarly, longer duration of breaks was associated with lower cardiovascular strain, indicated by increased RMSSD (B = 0.1, 95% CI 0.03, 0.1) and SDNN (B = 0.1, 95% CI 0.1, 0.1). Among pilots, increased LF/HF indicated higher cardiovascular strain in those who often or always reported of high workload (B = 4.3, 95% CI 2.3, 6.3; and B = 7.3, 95% CI 3.2, 11.4, respectively).DISCUSSION: The results support the contention that the studied work period increases cardiac strain among airline crew. Work characteristics, breaks, and sleep are associated with changes in HRV.Goffeng EM, Nordby K-C, Tarvainen M, Järvelin-Pasanen S, Wagstaff A, Skare Ø, Lie J-A. Cardiac autonomic activity in commercial aircrew during an actual flight duty period. Aerosp Med Hum Perform. 2019; 90(11):945-952.

Difference in the Effects of Lidocaine With Epinephrine and Prilocaine With Felypressin on the Autonomic Nervous System During Extraction of the Impacted Mandibular Third Molar: A Randomized Controlled Trial

Complications during local anesthesia include increased blood pressure and vasovagal reflex, which are caused by changes in the autonomic nervous system. The commonly used local anesthetic preparations are lidocaine to which the vasoconstrictor epinephrine is added (lidocaine-epinephrine) and prilocaine to which the vasoconstrictor felypressin is added (prilocaine-felypressin); however, their effects during dental treatment are unclear. We examined the effects of these 2 different local anesthetic preparations on the autonomic nervous system and circulation during extraction of the impacted mandibular third molar. In this randomized controlled trial, 40 female patients scheduled for extraction of an impacted mandibular third molar were randomized to the lidocaine-epinephrine group or prilocaine-felypressin group. Heart rate variability, heart rate, and systolic blood pressure were recorded during the experiment. Descriptive and bivariate statistics were computed, and the P value was set at .05. The low frequency-high frequency ratio was significantly increased in the prilocaine-felypressin group during extraction compared with that in the lidocaine-epinephrine group (P<.05). In the lidocaine-epinephrine group, a significant decrease in the high-frequency component was observed during bone removal and extraction compared with that at rest (P<.05). In both groups, a significant increase in systolic blood pressure was observed during local anesthesia, incision and reflection of the flap, bone removal, separation of the tooth crown, extraction, and suturing compared with that at rest (P<.01). This study is the first to investigate the differences in the influence of 2 different local anesthetic preparations on the autonomic nervous system during extraction of the mandibular third molar. Changes in circulatory dynamics during tooth extraction with the 2 different local anesthetic preparations were the result of a decrease in parasympathetic nervous activity with lidocaine-epinephrine and an increase in sympathetic nervous activity with prilocaine-felypressin.

PARAMETERS OF SPECTRAL AND TEMPORAL ANALYSIS OF HEART RATE VARIABILITY IN THE CONDITIONS OF DISREGULATION OF APOPTOTIC ACTIVITY IN BRONCHOPULMONARY PATHOLOGY AND COMORBIDITY WITH ARTERIAL HYPERTENSION

According to numerous reports, the prevalence rate of systemic arterial hypertension in patients with chronic pulmonary diseases varies from 0.4 to 27.7%. The number of authors have shown a decrease in heart rate variability against the background of hypertension, mainly due to the SDNN (the standard deviation of the normal-to-normal RR intervals) and RMSSD (the root mean square of successive RR-interval differences), indicating a decrease in parasympathetic effects on the heart rhythm and a relative increase in sympathetic tone.&#x0D; Objective: to study changes in heart rate variability parameters depending on the level of apoptotic processes in patients with arterial hypertension against the background of chronic obstructive pulmonary disease.&#x0D; Materials and methods. We examined 25 men with a diagnosis of arterial hypertension stage II and chronic obstructive pulmonary disease stage II without clinically significant comorbidities, whose average age was 51.72±1.22; more than 80% of them were active smokers, pack-years index was 17.06±2.41, the harmful professional factor were indicated by 1/4 people.&#x0D; The verification of arterial hypertension was carried out in accordance with the Order of the Ministry of Health of Ukraine dated May 24, 2012 № 384. All patients were diagnosed with stage II of hypertension. Arterial hypertension degree was diagnosed in 12% patients – first, in 28% patients – second and in 60% patients, respectively, third. Participants expressed their willingness to be included in medical research.&#x0D; Results. Index SDNN statistically significantly (p&lt;0.05) in parallel with the elevation of the values ​​of the marker of apoposis of caspase-9 decreased by 13.68%, comparing between groups of patients less and more than IV quartile according to the values ​​of caspase-9. The LF (Low Frequency power: frequency activity in the 0.04 - 0.15Hz range) value in patients with a cohort of less and more than IV quartile according to the values ​​of caspase-9 showed a statistically significant decrease by 32.67% (p &lt;0.05). HF (High Frequency power: frequency activity in the 0.15 - 0.40Hz range) with an increase in the activity of apoptosis processes according to the values ​​of caspase-9 decreased most significantly significant, by 48.92% (p &lt;0.05).&#x0D; To assess the direction, the tightness and the nature of the relationship between the indices between the studied variables, a regression analysis was conducted to construct a functional dependence. As independent argument (X) considered the level of caspase-9 activity, and as a dependent variable (Y) considered the indicator LF / HF (LF/HF Ratio: A ratio of Low Frequency to High Frequency). The obtained data indicated that the correlation between numerical variables in patients with caspase-9 level less than 4 quartiles had an unreliable character, while in patients with high expression of this cysteine ​​protease the correlation obtained with a high degree of accuracy and adequacy was approximated by the model of exponential form, and namely: Y = 4,0578 * exp (0,0901 * X) at R = 0,547, R2 = 0,30, normalized R2 = 0,29, p = 0,0083).&#x0D; Conclusion. Elevation of the state of the sympathetic part of the autonomic nervous system and a decrease in the activity of the parasympathetic part of the autonomic support, which can potentially be associated with an increased risk of serious cardiovascular cases in patients with this comorbidity, were found in patients with chronic obstructive pulmonary disease against the background of arterial hypertension.