Multiscale Cumulative Residual Dispersion Entropy with Applications to Cardiovascular Signals.

Heart rate variability (HRV) is used as an index reflecting the adaptability of the autonomic nervous system to external stimuli and can be used to detect various heart diseases. Since HRVs are the time series signal with nonlinear property, entropy has been an attractive analysis method. Among the various entropy methods, dispersion entropy (DE) has been preferred due to its ability to quantify the time series' underlying complexity with low computational cost. However, the order between patterns is not considered in the probability distribution of dispersion patterns for computing the DE value. Here, a multiscale cumulative residual dispersion entropy (MCRDE), which employs a cumulative residual entropy and DE estimation in multiple temporal scales, is presented. Thus, a generalized and fast estimation of complexity in temporal structures is inherited in the proposed MCRDE. To verify the performance of the proposed MCRDE, the complexity of inter-beat interval obtained from ECG signals of congestive heart failure (CHF), atrial fibrillation (AF), and the healthy group was compared. The experimental results show that MCRDE is more capable of quantifying physiological conditions than preceding multiscale entropy methods in that MCRDE achieves more statistically significant cases in terms of p-value from the Mann-Whitney test.

Enhancing SSVEP-Based Brain-Computer Interface with Two-Step Task-Related Component Analysis.

Among various methods for frequency recognition of the steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) study, a task-related component analysis (TRCA), which extracts discriminative spatial filters for classifying electroencephalogram (EEG) signals, has gathered much interest. The TRCA-based SSVEP method yields lower computational cost and higher classification performance compared to existing SSVEP methods. In spite of its utility, the TRCA-based SSVEP method still suffers from the degradation of the frequency recognition rate in cases where EEG signals with a short length window are used. To address this issue, here, we propose an improved strategy for decoding SSVEPs, which is insensitive to a window length by carrying out two-step TRCA. The proposed method reuses the spatial filters corresponding to target frequencies generated by the TRCA. Followingly, the proposed method accentuates features for target frequencies by correlating individual template and test data. For the evaluation of the performance of the proposed method, we used a benchmark dataset with 35 subjects and confirmed significantly improved performance comparing with other existing SSVEP methods. These results imply the suitability as an efficient frequency recognition strategy for SSVEP-based BCI applications.

Multiscale Distribution Entropy Analysis of Short-Term Heart Rate Variability.

Electrocardiogram (ECG) signal has been commonly used to analyze the complexity of heart rate variability (HRV). For this, various entropy methods have been considerably of interest. The multiscale entropy (MSE) method, which makes use of the sample entropy (SampEn) calculation of coarse-grained time series, has attracted attention for analysis of HRV. However, the SampEn computation may fail to be defined when the length of a time series is not enough long. Recently, distribution entropy (DistEn) with improved stability for a short-term time series has been proposed. Here, we propose a novel multiscale DistEn (MDE) for analysis of the complexity of short-term HRV by utilizing a moving-averaging multiscale process and the DistEn computation of each moving-averaged time series. Thus, it provides an improved stability of entropy evaluation for short-term HRV extracted from ECG. To verify the performance of MDE, we employ the analysis of synthetic signals and confirm the superiority of MDE over MSE. Then, we evaluate the complexity of short-term HRV extracted from ECG signals of congestive heart failure (CHF) patients and healthy subjects. The experimental results exhibit that MDE is capable of quantifying the decreased complexity of HRV with aging and CHF disease with short-term HRV time series.

Prevalence and associated factors of tinnitus: data from the Korean National Health and Nutrition Examination Survey 2009-2011.

BACKGROUND: Tinnitus is a common condition and frequently can be annoying to affected individuals. We investigated the prevalence and associated factors for tinnitus in South Korea using the data from the Korea National Health and Nutrition Examination Surveys (KNHANES) during 2009-2011. METHODS: KNHANES is a cross-sectional survey of the civilian, non-institutionalized population of South Korea (n = 21 893). A field survey team that included an otolaryngologist moved with a mobile examination unit and performed interviews and physical examinations. RESULTS: Among the population over 12 years of age, the prevalence of any tinnitus was 19.7% (95% CI 18.8%-20.6%). Tinnitus was more prevalent in women, and the prevalence rate increased with age (P < 0.001). Among those with any tinnitus, 29.3% (95% CI 27.3%-31.3%) experienced annoying tinnitus that affected daily life. Annoying tinnitus also increased with age (P < 0.001), but no sex difference was demonstrated (P = 0.25). In participants aged 40 years or older, age, quality of life, depressive mood, hearing loss, feeling of dizziness, and rhinitis were associated with any tinnitus (P < 0.05). Age, hearing loss, history of cardiovascular disease, and stress were associated with annoying tinnitus (P < 0.05). CONCLUSIONS: Tinnitus is a common condition, and a large population suffers from annoying tinnitus in South Korea. Public understanding of associated factors might contribute to better management of tinnitus.

Multiscale distribution entropy analysis of short epileptic EEG signals.

This paper proposes an information-theoretic measure for discriminating epileptic patterns in short-term electroencephalogram (EEG) recordings. Considering nonlinearity and nonstationarity in EEG signals, quantifying complexity has been preferred. To decipher abnormal epileptic EEGs, i.e., ictal and interictal EEGs, via short-term EEG recordings, a distribution entropy (DE) is used, motivated by its robustness on the signal length. In addition, to reflect the dynamic complexity inherent in EEGs, a multiscale entropy analysis is incorporated. Here, two multiscale distribution entropy (MDE) methods using the coarse-graining and moving-average procedures are presented. Using two popular epileptic EEG datasets, i.e., the Bonn and the Bern-Barcelona datasets, the performance of the proposed MDEs is verified. Experimental results show that the proposed MDEs are robust to the length of EEGs, thus reflecting complexity over multiple time scales. In addition, the proposed MDEs are consistent irrespective of the selection of short-term EEGs from the entire EEG recording. By evaluating the Man-Whitney U test and classification performance, the proposed MDEs can better discriminate epileptic EEGs than the existing methods. Moreover, the proposed MDE with the moving-average procedure performs marginally better than one with the coarse-graining. The experimental results suggest that the proposed MDEs are applicable to practical seizure detection applications.

Numerical study on the hydrodynamic performance and internal flow of an axial-flow pump with various inlet flow angles.

In this study, numerical simulation was employed to predict the performance and internal flow characteristics of the inlet of an axial-flow pump by assigning an absolute flow angle to the inlet guide vane (IGV) trailing-edge flow. Further, the finite volume method based on the three-dimensional Reynolds-averaged Navier-Stokes equations was employed to discretize the governing equations. The shear stress transport model was used as the turbulence model, and an appropriate number of nodes were selected for the hexahedral grid system through a grid-dependency test. The performance curve and changes in the internal flow field were investigated based on the variation in the flow angle at the inlet of the axial-flow pump. These results can be used to establish an efficient operational plan by adjusting the IGV angle of IGV when installing a variable IGV for an axial-flow pump.

Numerical investigation on functional limitations of the anti-stall fin for an axial fan: one-factor analyses.

The stall in an axial fan is directly related to detrimental phenomena such as performance degradation, vibration, noise, and flow instability at low flow rates. As a kind of passive control method to handle the stall, two-dimensional plates so-named anti-stall fin (ASF) were suggested by ourselves and were attached inside the casing. In this study, the ASF's effect on the internal flow pattern was visually investigated in the flow passage, and its tendency was discussed with the performance curve. Subsequently, the ASF's functional limitations for various design parameters, which the ASF can derive aerodynamically, were presented as the primary focus of this study. Each one-factor analysis was performed, and the internal flow pattern was observed in parallel at the point where the ASF lost its function. For the radial length, axial length, number of fins, and positive-tangential angle, the ASF almost retained its function up to the limitation to prevent instability but radically lost its function at a certain flow rate. For the axial gap and negative-tangential angle, the ASF gradually lost its function. Mostly, this study was based on numerical analysis, and the performance was validated through experimental tests.

The increased analgesic efficacy of cold therapy after an unsuccessful analgesic experience is associated with inferior parietal lobule activation.

Prior experiences of successful and failed treatments are known to influence the efficacy of a newly applied treatment. However, whether that carry-over effect applies to non-pharmacological treatments is unknown. This study investigated how a failed treatment history with placebo analgesic cream affected the therapeutic outcomes of cold-pack treatment. The neural correlates underlying those effects were also explored using functional magnetic resonance imaging. The effect of the placebo analgesic cream was induced using placebo conditioning with small (44.5 °C to 43.7 °C, negative experience) and large (44.5 °C to 40.0 °C, positive experience) thermal stimuli changes. After the placebo conditioning, brain responses and self-reported evaluations of the effect of subsequent treatment with a cold-pack were contrasted between the two groups. The negative experience group reported less pain and lower anxiety scores in the cold-pack condition than the positive experience group and exhibited significantly greater activation in the right inferior parietal lobule (IPL), which is known to be involved in pain relief. These findings suggest that an unsatisfying experience with an initial pain-relief treatment could increase the expectations for the complementary treatment outcome and improve the analgesic effect of the subsequent treatment. The IPL could be associated with this expectation-induced pain relief process.

Correlation between short-time and whole-night obstruction level tests for patients with obstructive sleep apnea.

Identification of obstructive level is crucial for successful surgical outcomes in patients with obstructive sleep apnea (OSA). Unfortunately, most of the dynamic airway evaluations are performed for a short duration under drug-induced sleep; therefore, it is uncertain whether they represent airway events that occur during a whole night of sleep. This study was aimed to evaluate the correlation between obstructive levels that were identified by a short-time and a whole-night test in patients with OSA. Total 101 patients with OSA underwent drug-induced sleep fluoroscopy (DISF) and pressure manometry (PM). For DISF, the obstructive pattern was classified into one of three groups: soft palate, tongue-based, and a combined obstruction. PM was used to measure the proportion of retroglossal events out of total whole-night obstructive events in each patient. The mean age of the patients was 43.8 years. The obstructive pattern was identified as soft palate in 56 patients, combined in 38 patients, and tongue-based in 7 patients following DISF. Results from PM showed that the mean percentage of retroglossal obstructive events was 31.2 ± 30.7%. The average proportion of retroglossal obstructive events that were identified by PM in patients with soft palate, combined, and tongue-based obstruction was 27.2%, 32.1%, and 59.0%, respectively (p = 0.033). There are limitations of evaluating obstructive events that occur during a whole night with short-time tests. Surgeons should be aware the possibility of disagreement in the obstructive level between short-time and whole-night tests.

Evaluation of the Esthetic and Functional Outcomes of Extracorporeal Septoplasty for Rhinoplasty in Asian Patients.

OBJECTIVES: In extracorporeal septoplasty (ECS), the entire septal cartilage is harvested, and a neo-L strut is built extracorporeally. Thus, ECS can simultaneously achieve septum straightening and tip projection. This study evaluated the functional and esthetic outcomes of the ECS technique for rhinoplasty in Asian patients. METHODS: We conducted a retrospective review of 64 patients who underwent rhinoplasty using ECS between January 2016 and March 2018. Subjective patient satisfaction was assessed and objective surgical outcomes were evaluated. Improvement in nasal obstruction was rated using a visual analog scale (VAS). Anthropometric changes were compared between preoperative and postoperative facial photographs. Complications and revisions were also analyzed. RESULTS: The participants comprised 64 patients (48 males and 16 females, with a mean age of 29.3 years). The mean operative time was 89.3 minutes. In total, 61 patients were satisfied with the esthetic outcome, and the overall objective rhinoplasty outcome score was 3.45. Preoperative nasal obstruction symptoms (7.9±1.2 on VAS) improved postoperatively (3.1±1.3, P<0.001), and significant improvements were also observed in the nasofrontal angle (152.3° to 148.1°, P<0.001), nasolabial angle (88.8° to 92.0°, P<0.001), and nasal tip projection (0.62 to 0.66, P<0.033). Recurrent deviation of the nasal septum and external nose or tip deprojection did not occur in any patients, and there were no cases of revision during the mean follow-up period of 13.3 months. CONCLUSION: ECS might be an esthetically and functionally satisfactory alternative rhinoplasty technique for Asian patients with a shortage of septal cartilage.

Clinical Efficacy and Safety of Low-Level Laser Therapy in Patients with Perennial Allergic Rhinitis: A Randomized, Double-Blind, Placebo-Controlled Trial.

Allergic rhinitis (AR) is a common disease that interferes with the daily activities and reduces the quality of life. Conventional treatments often do not provide complete resolution of the symptoms, and many new treatment modalities have been tried. This study aimed to evaluate the efficacy and safety of low-level laser therapy (LLLT) for AR in a randomized, double-blind, placebo-controlled trial. Patients diagnosed with AR were randomly allocated to receive LLLT or sham treatment. The primary outcome was a change in the reflective total nasal symptom score (TNSS). The secondary outcome was quality of life scores assessed using the Rhinoconjunctivitis Quality of Life Questionnaire. Incidences of adverse events were also recorded. Among 67 randomized subjects, 41 subjects (22 in LLLT group and 19 in sham treatment group) were included for efficacy analysis. The LLLT group showed a significantly improved TNSS score compared to the sham treatment group for decreasing AR symptom severity (p = 0.011) and improving quality of life regarding nasal symptoms (p = 0.036) at the end of treatment. Throughout the treatment period, no severe adverse events occurred. This clinical trial showed that LLLT is an effective and safe option for the management of AR regarding symptom relief and quality of life improvement.

Dexamethasone and post-adenotonsillectomy pain in children: Double-blind, randomized controlled trial.

OBJECTIVE: To assess the impact of intraoperative intravenous dexamethasone on the reduction of postoperative morbidity in children undergoing adenotonsillectomy. METHODS: A double blind randomized controlled trial conducted among children undergoing adenotonsillectomy at a tertiary hospital in Korea from November 2018 to June 2019. Children were randomly assigned to receive dexamethasone (0.5 mg/kg, maximum dose 24 mg) or placebo intravenously after induction of anesthesia. The primary endpoint was the reduction of postoperative pain and postoperative nausea and vomiting (PONV); secondary endpoints were adverse effects like postoperative hemorrhage. RESULTS: The study included 105 children, and 67 were male. Their mean age was 6.2 ±â€Š2.1 years. There was no significant difference between the groups in terms of demographic data or the operation time. The pain scores of the dexamethasone group were lower than those of the control group, but no significant difference was found (all P > .05). The average pain visual analog scale (VAS) during the study period (day 0-7) was 3.67 ±â€Š1.59 and 4.40 ±â€Š2.01 in the dexamethasone group and control group, respectively (P-value = .107). When we compared early pain VAS (day 0-2) and late pain VAS (day 5-7), the dexamethasone group showed significantly lower early mean VAS compared to the control group (4.55 ±â€Š1.78 vs 5.40 ±â€Š2.05, P-value = .046). The mean VAS for PONV was significantly lower in the dexamethasone group than in the control group (1.89 ±â€Š2.22 vs 3.00 ±â€Š2.37, P value = .044). CONCLUSION: In children undergoing adenotonsillectomy, dexamethasone decreased the early postoperative pain and PONV without increasing postoperative hemorrhage.

Increased Risk of Psychopathological Abnormalities in Subjects With Unilateral Hearing Loss: A Cross-Sectional Study.

OBJECTIVES: Although unilateral hearing loss (UHL) has been proven to be associated with educational and behavioral problems, few studies have investigated psychopathological abnormalities in this population. The aim of this study was to evaluate the psychopathological influence of UHL among Korean 19-year-old males. METHODS: The authors retrospectively compared the objective personality test profiles of 602 subjects with UHL with those of 23,790 peers with normal hearing. All participants in the current study were 19-year-old males who underwent a physical examination and completed the Korean Military Multiphasic Personality Inventory for conscription at the Military Manpower Administration from February 2015 to December 2016. RESULTS: Significantly higher scores were found on neurosis scales in the UHL group than in the normal-hearing group (50.9± 10.8 vs. 44.9±6.0 for anxiety; 51.0±10.5 vs. 44.9±5.2 for depression; 51.1±10.4 vs. 45.1±6.81 for somatization, all P<0.001). The psychopathy scales were also significantly higher in the UHL group than in the normal-hearing group (49.3±9.4 vs. 46.3±5.7 for schizophrenia; 51.1±11.2 vs. 44.3±5.8 for personality disorders; 51.1±10.5 vs. 45.7±3.7 for paranoia, all P<0.001). CONCLUSION: Nineteen-year-old males with UHL tended to have more abnormal results on personality tests than controls with normal hearing, suggesting that UHL may be related with a higher risk of psychopathology.

Unusual properties of catalase A (KatA) of Pseudomonas aeruginosa PA14 are associated with its biofilm peroxide resistance.

Pseudomonas aeruginosa is a ubiquitous environmental bacterium whose major catalase (KatA) is highly stable, extracellularly present, and required for full virulence as well as for peroxide resistance in planktonic and biofilm states. Here, we dismantled the function of P. aeruginosa KatA (KatA(Pa)) by comparing its properties with those of two evolutionarily related (clade 3 monofunctional) catalases from Bacillus subtilis (KatA(Bs)) and Streptomyces coelicolor (CatA(Sc)). We switched the coding region for KatA(Pa) with those for KatA(Bs) and CatA(Sc), expressed the catalases under the potential katA-regulatory elements in a P. aeruginosa PA14 katA mutant, and verified their comparable protein levels by Western blot analysis. The activities of KatA(Bs) and CatA(Sc), however, were less than 40% of the KatA(Pa) activity, suggestive of the difference in intrinsic catalatic activity or efficiency for posttranslational activity modulation in P. aeruginosa. Furthermore, KatA(Bs) and CatA(Sc) were relatively susceptible to proteinase K, whereas KatA(Pa) was highly stable upon proteinase K treatment. As well, KatA(Bs) and CatA(Sc) were undetectable in the extracellular milieu. Nevertheless, katA(Bs) and catA(Sc) fully rescued the peroxide sensitivity and osmosensitivity of the katA mutant, respectively. Both catalase genes rescued the attenuated virulence of the katA mutant in mouse acute infection and Drosophila melanogaster models. However, the peroxide susceptibility of the katA mutant in a biofilm growth state was rescued by neither katA(Bs) nor catA(Sc). Based on these results, we propose that the P. aeruginosa KatA is highly stable compared to the two major catalases from gram-positive bacteria and that its unique properties involving metastability and extracellular presence may contribute to the peroxide resistance of P. aeruginosa biofilm and presumably to chronic infections.

Results of Hearing Outcome According to the Alloplastic Ossicular Prosthesis Materials.

The aim of this study is to compare the functional results and extrusion rates according to the type of ossciular alloplastic prosthesis. In this study, a retrospective analysis was performed. Sixty-one patients were involved in partial ossicular replacement (POR) cases and 70 patients were involved in total osscicular replacement (TOR) cases. In POR cases, Plastipore was used in 21 cases, hydroxyapatite in 20 cases, and titanium in 20 cases. In TOR cases, Plastipore was used in 20 cases, hydroxyapatite (HA) in 25 cases and titanium in 25 cases. We reviewed postoperative ABG (less than 20 dB or more than 20 dB) and the extrusion rate for more than 1 year follow-up period. In POR cases, ABG less than 20 dB were 71.4, 80.0, 85.0 % in plastipore, HA, and titanium prosthesis and in TOR cases, ABG less than 20 dB were 25.0, 28.0, 32.0 % in plastipore, HA, and titanium prostheses, respectively. In POR cases, extrusion rates (ER) were 9.5, 5.0, 5.0 % in plastipore, HA, and titanium prosthesis, respectively. In TOR cases, ER were 15.0, 8.0, 4.0 % in plastipore, HA, and titanium prosthesis, respectively. There were no significant differences in hearing gain results among plastipore, HA, and titanium in both POR and TOR cases, but the ER was significantly low in titanium. Clinically relatively better hearing gain and low-rate of extrusion were found in titanium prosthesis and thus this material is recommended in cases of ossicular alloplastic replacement surgery.

Endoscopic versus external repair of orbital blowout fractures.

OBJECTIVES: This study evaluates the usefulness of endoscopic repair compared to external repair in the treatment of blowout fracture (BOF) of the orbit. STUDY DESIGN AND SETTING: This retrospective study comprised 100 patients who had had surgical repair of orbital BOF since 1992. Forty-eight of the 100 had undergone endoscopic repair, 48 patients had had external repair, and four patients underwent surgery that combined the two approaches. The two basic approaches were evaluated and compared with respect to technique, results and complications. RESULTS: Endoscopically, transnasal and transantral approaches had been used for reduction and support of fractured medial and inferior walls, respectively. In the external approach, various transorbital incisions were made and the fractured wall was repaired with alloplastic or autologous materials. Complete or partial resolution of preoperative diplopia was achieved in 94% of the endoscopic group and 83% of the external group (NS). Enophthalmos was improved in 89% of the endoscopic group and 76% of the external group (NS). Though the endoscopic group had no significant complications, the external group had ectropions, significant facial scars, extrusion of inserted Medpor, and intra-orbital hematoma. CONCLUSIONS: Endoscopic repair appears to be a safe and effective technique for the treatment of BOF of the orbit.

Identification of Pseudomonas aeruginosa genes crucial for hydrogen peroxide resistance.

An opportunistic human pathogen, Pseudomonas aeruginosa, contains the major catalase KatA, which is required to cope with oxidative and osmotic stresses. As an attempt to uncover the H2O2-dependent regulatory mechanism delineating katA gene expression, four prototrophic H2O2-sensitive mutants were isolated from about 1,500 TnphoA mutant clones of P. aeruginosa strain PA14. Arbitrary PCR and direct cloning of the transposon insertion sites revealed that one insertion is located within the katA coding region and two are within the coding region of oxyR, which is responsible for transcriptional activation of several antioxidant enzyme genes in response to oxidative challenges. The fourth insertion was within PA3815 (IscR), which encodes a homolog of the Escherichia coli iron-sulfur assembly regulator, IscR. The levels of catalase and SOD activities were significantly reduced in the iscR mutant, but not in the oxyR mutant, during the normal planktonic culture conditions. These results suggest that both IscR and OxyR are required for the optimal resistance to H2O2, which involves the expression of multiple antioxidant enzymes including KatA.

Effects of Mixed Bone and Brisket Meat on Physico-Chemical Characteristics of Shank Bone and Rib Extracts from Hanwoo.

This study was conducted to investigate the effects of mixed bone and brisket meat on the quality characteristics and nutritional components of shank bone extract and rib extract from Hanwoo. The pH values were influenced by the raw bones, mixed bone, brisket meat and their interactions (p<0.05). The salinity, sugar content, turbidity, and essential amino acid values increased significantly with addition of mixed bone and brisket meat. All attributes of sensory evaluation score were the highest in T6 (Rib 500 g + Mixed bone 500 g + Brisket meat 400 g) (p<0.05). The mixed bone significantly increased the saturated fatty acids of shank bone extract (p<0.001). Thus, the addition of mixed bone and brisket meat had a positive effect on the quality and nutritional components in shank and rib extracts of Hanwoo cattle.

Conserved virulence factors of Pseudomonas aeruginosa are required for killing Bacillus subtilis.

The multi-host pathogen, Pseudomonas aeruginosa, possesses an extraordinary versatility which makes it capable of surviving the adverse conditions provided by environmental, host, and, presumably, competing microbial factors in its natural habitats. Here, we investigated the P. aeruginosa-Bacillus subtilis interaction in laboratory conditions and found that some P. aeruginosa strains can outcompete B. subtilis in mixed planktonic cultures. This is accompanied by the loss of B. subtilis viability. The bactericidal activity of P. aeruginosa is measured on B. subtilis plate cultures. The bactericidal activity is attenuated in pqsA, mvfR, lasR, pilB, gacA, dsbA, rpoS, and phnAB mutants. These results suggest that P. aeruginosa utilizes a subset of conserved virulence pathways in order to survive the conditions provided by its bacterial neighbors.