Remote sensing of vital signs by medical radar time-series signal using cardiac peak extraction and adaptive peak detection algorithm: Performance validation on healthy adults and application to neonatal monitoring at an NICU.

BACKGROUND AND OBJECTIVE: Continuous monitoring of vital signs plays a pivotal role in neonatal intensive care units (NICUs). In this paper, we present a system for monitoring fully non-contact medical radar-based vital signs to measure the respiratory rate (RR), heart rate (HR), I:E ratio, and heart rate variability (HRV). In addition, we evaluated its performance in a physiological laboratory and examined its adaptability in an NICU. METHODS: A non-contact medical radar-based vital sign monitoring system that includes 24 GHz radar installed in an incubator was developed. To enable reliable monitoring, an advanced signal processing algorithm (i.e., a nonlinear filter to separate respiration and heartbeat signals from the output of radar), template matching to extract cardiac peaks, and an adaptive peak detection algorithm to estimate cardiac peaks in time-series were proposed and implemented in the system. Nine healthy subjects comprising five males and four females (24 ± 5 years) participated in the laboratory test. To evaluate the adaptability of the system in an NICU setting, we tested it with three hospitalized infants, including two neonates. RESULTS: The results indicate strong agreement in healthy subjects between the non-contact system and reference contact devices for RR, HR, and inter-beat interval (IBI) measurement, with correlation coefficients of 0.83, 0.96, and 0.94, respectively. As anticipated, the template matching and adaptive peak detection algorithms outperformed the conventional approach. These showed a more accurate IBI close to the reference Bland-Altman analysis (proposed: bias of -3 ms, and 95% limits of agreement ranging from -73 to 67 ms; conventional: bias of -11 ms, and 95% limits of agreement ranging from -229 to 207 ms). Moreover, in the NICU clinical setting, the IBI correlation coefficient and 95% limit of agreement in the conventional method are 0.31 and 91 ms. The corresponding values obtained using the proposed method are 0.93 and 21 ms. CONCLUSION: The proposed system introduces a novel approach for NICU monitoring using a non-contact medical radar sensor. The signal processing method combining cardiac peak extraction algorithm with the adaptive peak detection algorithm shows high adaptability in detecting IBI the time series in various application settings.

Proof-of-principle Experiment on 24 GHz Medical Radar for Non-contact Vital Signs Measurement.

Medical radar for non-contact vital signs measurement exhibits great potential in both clinical and home healthcare settings. Especially during the corona virus spreading time, non-contact sensing more clearly shows the advantages. Many previous studies have concentrated on medical radar-based healthcare applications, but pay less attention to the working principles. A clear understanding of medical radars at both the mathematical and physical levels is critically important for developing application-specific signal processing algorithms. Therefore, this study aims to re-define the operating principle of radar, and a proof-of-principle experiment was performed on both actuator and human subjects using 24 GHz Doppler radar system. Experimental results indicate that there is a difference in the radar output signals between the two cases, where the displacement is greater than and less than half of the wavelength. For the former situation, the displacement x = n.λ/2 (n ≥ 1), one peak of radar signals corresponds to n peaks of baseband signals. By contrast, for the latter situation, the displacement x < λ/2, one peak of radar signals corresponds to one peak of baseband signals. Strikingly, with human measurement on the dorsal side, the the number of respiration peaks are seen from the radar raw signals.

Design and Evaluation of Digital Filters for Non-Contact Measuring of HRV using Medical Radar and Its Application in Bedside Patient Monitoring System.

A non-contact bedside monitoring system using medical radar is expected to be applied to clinical fields. Our previous studies have developed a monitoring system based on medical radar for measuring respiratory rate (RR) and heart rate (HR). Heart rate variability (HRV), which is essentially implemented in advanced monitoring system, such as prognosis prediction, is a more challenging biological information than the RR and HR. In this study, we designed a HRV measurement filter and proposed a method to evaluate the optimal cardiac signal extraction filter for HRV measurement. Because the cardiac component in the radar signal is much smaller than the respiratory component, it is necessary to extract the cardiac element from the radar output signal using digital filters. It depends on the characteristics of the filter whether the HRV information is kept in the extracted cardiac signal or not. A cardiac signal extraction filter that is not distorted in the time domain and does not miss the cardiac component must be adopted. Therefore, we focused on evaluating the interval between the R-peak of the electrocardiogram (ECG) and the radar-cardio peak of the cardiac signal measured by radar (R-radar interval). This is based on the fact that the time between heart depolarization and ventricular contraction is measured as the R-radar interval. A band-pass filter (BPF) with several bandwidths and a nonlinear filter, locally projective adaptive signal separation (LoPASS), were analyzed and compared. The optimal filter was quantitatively evaluated by analyzing the distribution and standard deviation of the R-radar intervals. The performance of this monitoring system was evaluated in elderly patient at the Yokohama Hospital, Japan.

Discovery of α-Glucosidase Inhibitors from Marine Microorganisms: Optimization of Culture Conditions and Medium Composition.

Various studies showed that the suppression of α-glucosidase activity can impede the glucose absorption in our body, and therefore, it can be used to treat type 2 diabetes. Hence, the compounds with anti-α-glucosidase have gained considerable attention because of their potential application in diabetes treatment. In previous literature studies, these anti-α-glucosidase compounds were extracted from plants and fungus. Less studies are being conducted to identify the anti-α-glucosidase compounds in the microbial community. In this study, 23 marine bacterial strains were screened for their potential to suppress the α-glucosidase activity. The highest inhibitory activity was exhibited by isolated L06 which was identified as Oceanimonas smirnovii EBL6. The cultivation conditions, such as temperature and pH, were optimized to increase the production of α-glucosidase inhibitors by Oceanimonas smirnovii EBL6 strain. The result findings showed that the highest yield of α-glucosidase inhibitors can be obtained at the culture time of 120 h, fermentation temperature of 30 °C, and pH 4.6. Under these conditions, the inhibitory activity of α-glucosidase can reach 81%. The IC50 of n-butanol extract was 13.89 µg/ml, while standard acarbose was 31.16 µg/ml. Overall, these findings suggest that Oceanimonas smirnovii produces α-glucosidase inhibitors and could been applied in the biochemical and medicinal fields in the future.

Impact of School-Based Oral Health Education on Vietnamese Adolescents: A 6-Month Study.

We have evaluated the impact of a school-based intervention on oral health knowledge, behaviours, and oral health status of adolescents in Vietnam. This 6-month study included 462 adolescents aged 12 years from four selected schools in Hue City, Vietnam. The intervention group received a 15-min lecture by a dentist and hands-on session on mouth observation and toothbrushing skills. The control group did not engage in any educational activities during the follow-up period. Data were collected at baseline and 6 months through a survey questionnaire and clinical examination. The Debris Index was used for dental plaque; the Papillary, Marginal, Attached gingiva index for gingivitis; and the Decayed, Missing, and Filled Teeth index (World Health Organization modification) for dental caries. Difference-in-difference analysis was used to compare changes between the groups. After 6 months, the control tended to show decreased toothbrushing frequency and increased dental plaque accumulation. The participants in the intervention group showed improved oral health knowledge (p < 0.01), behavior (p < 0.05), and hygiene (p < 0.001) compared to the control group. However, the intervention did not improve dental caries and gingivitis. A single school-based oral health education program can help adolescents improve oral health knowledge and prevent the deterioration of short-term oral health behavior and hygiene.

Selection, purification, and evaluation of acarbose-an α-glucosidase inhibitor from Actinoplanes sp.

Actinoplanes sp. A1094 strain had been selected for its high production of acarbose from 20 different strains of Actinoplanes sp. can be found in wild. The content for glucosidase inhibitor of acarbose concentration was recorded at 1.12 g/L. The conducted analysis of 16S rRNA sequence of Actinoplanes sp. A1094 showed 99% similar identity to the corresponding sequence of Actinoplanes hulinensis. Acarbose was purified from Actinoplanes hulinensis 1094 with a yield of 8.48%, purity of 98% and further identified by LC/MS and NMR methods (C25H43NO18; m/z: 645.6 g/mol). The purified acarbose was used to evaluate the hypoglycemia in streptozotocin (STZ)-induced diabetic mice model. The purified acarbose reduced postprandial blood glucose level in comparison with Glucobay® as medication for control type 2 diabetes in a combination therapy. Notably, the outcomes of native acarbose on fasting blood glucose levels in mice resemble akin to the commercial product and the acarbose accumulating fermentation and metabolic engineering from the cell gene in which would reduce in production cost. Therefore, acarbose from Actinoplanes hulinensis 1094 could be potentially used to make products for the treatment of type II diabetes.

Identifying Developmental Language Disorder in Vietnamese Children.

Purpose Developmental language disorder (DLD), defined by low language performance despite otherwise normal development, can negatively impact children's social and academic outcomes. This study is the 1st to examine DLD in Vietnamese. To lay the foundation, we identified cases of DLD in Vietnam and explored language-specific characteristics of the disorder. Method Teacher ratings of 1,250 kindergarteners living in Hanoi, Vietnam, were used to recruit children with and without risk for DLD. One hundred four children completed direct measures of vocabulary and language sampling, and their parents completed in-depth surveys. We examined convergence and divergence across tasks to identify measures that could serve as reliable indicators of risk. Then, we compared performance on direct language measures across ability levels. Results There were positive associations between teacher and parent report and between report and direct language measures. Three groups were identified based on convergence across measures: DLD, some risk for DLD, and no risk. The DLD group performed lowest on measures of receptive and expressive vocabulary, mean length of utterance, and grammaticality. Although children with DLD exhibited a greater number of errors, the types of errors found were similar across DLD and No Risk groups. Conclusions Similar to rates found globally, 7% of the kindergarten population in Vietnam exhibited risk for DLD. Results highlight the importance of parent and teacher report and the value of multiple measures to identify DLD. We discuss potential clinical markers for DLD in the Vietnamese language and outline future directions.

Early Childhood Caries and Risk Factors in Vietnam.

OBJECTIVE: To investigate caries prevalence and examine its relationship with socioeconomic status and oral health behavior of Vietnamese kindergarten children. STUDY DESIGN: The study was carried out on 1,028 children aged 2-5 years in six kindergartens in Thua Thien Hue province, Vietnam. Information about socioeconomics and oral health behaviors was collected through a self-administered questionnaire, and oral health status by clinical dental examination. RESULTS: Clinical dental examination found that overall caries prevalence and mean dmft were 89.1% and 9.32. Caries prevalence and mean dmft increased greatly from two years to three years old, and gradually developed from three years to five years old. A logistic regression revealed that caries had an inverse relationship with mothers' educational level and a positive relationship with the habit of retaining food in the mouth for a long time in two-year-old children. Prolonged breastfeeding, more frequent sweets consumption, no thumb sucking habit, and higher modified debris index score were the risk factors for caries among three-to-five-year-old children. CONCLUSIONS: This study indicated a high prevalence of caries and related risk factors such as low mother's educational level and inappropriate oral health behavior among kindergarten children in Vietnam.

Chemical constituents of Trichosanthes kirilowii and their cytotoxic activities.

One new lignan, trichobenzolignan (1), and seven known compounds, ligballinol (2), (-)-pinoresinol (3), ehletianol C (4), luteolin 7-O-ß-D-glucopyranoside (5), chrysoeriol-7- O-ß-D-glucopyranoside (6), 10α-cucurbita-5,24-dien-3ß-ol (7), and arvenin I (8). Their structures were established on the basis of spectral and chemical evidence, which were in agreement with those reported in literature. The cytotoxic activities of these compounds were evaluated on four cancer cell lines such as A-549 (human lung cancer), HT-29 (human colon adenocarcinoma), OVCAR (human ovarian carcinoma), and MCF-7 (human breast cancer). As the results, compound 7 showed significant activity on HT-29 and OVCAR cancer cell lines with IC50 of 4.1 and 6.5 µM, respectively. Compounds 1, 5, 6, and 8 exhibited moderate activities in all cancer cell lines with IC50 ranging from 11.3 to 42.8 µM.