Improving LCC Series-Based Wireless Power Transfer System Output Power at High Temperature

Adding a core to a coupling coil can improve transmission efficiency. However, the added core causes the self-inductance of the coupling coil to increase at a high temperature due to the temperature-sensitive property of the core material’s permeability. The self-inductance increases, causing the resonance frequency to shift down, thereby decreasing the output power. The 3 dB bandwidth of the system can learn of the correspondence between the output power and the resonance frequency. In order to make sure that the output power does not excessively decrease at a high temperature, this study employs a simulation for the LCC-S-based wireless power transfer system. Adding a minor resistance to shift down the lower cutoff frequency ensures that the resonance frequency yielded by the temperature rise can be higher than the lower cutoff frequency, making the output power higher than half of the maximum. Then, an adjustment on the compensation capacitances on the resonant circuit elevates the output power more. The outcomes are consistent with the prediction. Adding the core to the coupling coil improves transmission efficiency; increasing the bandwidth of the system excessively decreases the output power decline at a high temperature for the temperature-sensitive core material permeability.

Olfactory impairment in mild cognitive impairment with Lewy bodies and Alzheimer’s disease

ABSTRACT Objectives: Impaired olfaction may be a biomarker for early Lewy body disease, but its value in mild cognitive impairment with Lewy bodies (MCI-LB) is unknown. We compared olfaction in MCI-LB with MCI due to Alzheimer’s disease (MCI-AD) and healthy older adults. We hypothesized that olfactory function would be worse in probable MCI-LB than in both MCI-AD and healthy comparison subjects (HC). Design: Cross-sectional study assessing olfaction using Sniffin’ Sticks 16 (SS-16) in MCI-LB, MCI-AD, and HC with longitudinal follow-up. Differences were adjusted for age, and receiver operating characteristic (ROC) curves were used for discriminating MCI-LB from MCI-AD and HC. Setting: Participants were recruited from Memory Services in the North East of England. Participants: Thirty-eight probable MCI-LB, 33 MCI-AD, 19 possible MCI-LB, and 32HC. Measurements: Olfaction was assessed using SS-16 and a questionnaire. Results: Participants with probable MCI-LB had worse olfaction than both MCI-AD (age-adjusted mean difference (B) = 2.05, 95% CI: 0.62–3.49, p = 0.005) and HC (B = 3.96, 95% CI: 2.51–5.40, p < 0.001). The previously identified cutoff score for the SS-16 of ≤ 10 had 84% sensitivity for probable MCI-LB (95% CI: 69–94%), but 30% specificity versus MCI-AD. ROC analysis found a lower cutoff of ≤ 7 was better (63% sensitivity for MCI-LB, with 73% specificity vs MCI-AD and 97% vs HC). Asking about olfactory impairments was not useful in identifying them. Conclusions: MCI-LB had worse olfaction than MCI-AD and normal aging. A lower cutoff score of ≤ 7 is required when using SS-16 in such patients. Olfactory testing may have value in identifying early LB disease in memory services.

The Effect of Vitamin D Supplementation on Severe COVID-19 Outcomes in Patients With Vitamin D Insufficiency

Introduction: Coronavirus Disease 2019 (COVID-19) deaths have surpassed one million worldwide with limited treatment modalities, and physicians are relying on alternative methods, such as Vitamin D supplementation, to prevent or halt disease progression without direct evidence. Research has proven that vitamin D supplementation can prevent inflammation based on its role in innate immune response; however, there have been limited studies regarding vitamin D supplementation in COVID-19. We aimed to determine whether vitamin D supplementation in vitamin D insufficient patients was associated with fewer severe COVID-19 outcomes, defined as mechanical ventilation or death. Methods: Retrospective study that analyzed data from all adult patients admitted to our tertiary care center between March 2020 and July 2020 with a positive RT-PCR for SARS CoV-2 and a serum 25-hydroxyvitamin D (25[OH]D) level measured within 90 days prior to the index admission. Patients with 25(OH)D &lt;30 ng/mL were considered vitamin D insufficient and patients ordered for least one weekly dose of ≥1,000 units of ergocalciferol or cholecalciferol were considered supplemented. Supplemented vitamin D insufficient patients were compared to non-supplemented vitamin D insufficient patients in terms of severe COVID-19 disease as defined by mechanical ventilation or death. Results: 129 COVID-19 patients with a vitamin D level &lt;30 ng/mL were identified, with a median vitamin D level of 21.4 ng/mL. A total of 43 patients (33.3%) had severe COVID-19 outcomes. 65 (50.4%) patients with vitamin D insufficiency were supplemented and 64 (49.6%) were not supplemented. Vitamin D supplementation with ≥1,000 units (OR 0.6, 95% CI 0.28 - 1.40; p=0.25), ≥5,000 units (OR 0.5, 95% CI 0.26 - 1.23; p=0.15), or ≥50,000 units (OR 1.0, 95% CI 0.42–2.20, p=0.92) weekly had no statistically significant effect on severe COVID-19 outcomes. The odds of severe COVID-19 outcomes in supplemented patients were non-significantly reduced at lower cutoff values for vitamin D insufficiency (&lt;20 ng/mL and &lt;12 ng/mL) for all supplementation amounts. Conclusion: Vitamin D supplementation in patients with vitamin D insufficiency did not significantly reduce severe COVID-19 outcomes; however, vitamin D supplementation was associated with non-statistically significant reduced odds of severe COVID-19 outcomes at lower cutoff values of vitamin D level. These results demonstrate that Vitamin D supplementation may have a protective effect against severe COVID-19 outcomes in patients with lower baseline levels of vitamin D.

A Simplified Point-of-Care Lung Ultrasound Protocol to Detect Coronavirus Disease 2019 in Inpatients: A Prospective Observational Study

Objectives: To assess the diagnostic performance of lung point-of-care ultrasound (POCUS) compared to either a positive nucleic acid test (NAT) or a COVID-19-typical pattern on computed tomography (CT) and to evaluate opportunities to simplify a POCUS algorithm. Methods: Hospital-admitted adult inpatients with (1) either confirmed or suspected COVID-19 and (2) a completed or ordered CT within the preceding 24 hours were recruited. Twelve lung zones were scanned with a handheld POCUS machine. POCUS, CT, and X-ray (CXR) images were reviewed independently by blinded experts. A simplified POCUS algorithm was developed via machine learning. Results: Of 79 enrolled subjects, 26.6% had a positive NAT and 31.6% had a CT typical for COVID-19. The receiver operator curve (ROC) for a 12-zone POCUS protocol had an area under the curve (AUC) of 0.787 for positive NAT and 0.820 for typical CT. A simplified four-zone protocol had an AUC of 0.862 for typical CT and 0.862 for positive NAT. CT had an AUC of 0.815 for positive NAT; CXR had AUCs of 0.793 for positive NAT and 0.733 for typical CT. Performance of the four-zone protocol was superior to CXR for positive NAT (p=0.0471). Using a two-point cutoff system, the four-zone POCUS protocol had a sensitivity of 0.920 and 0.904 compared to CT and NAT, respectively, at the lower cutoff; it had a specificity of 0.926 and 0.948 at the higher cutoff, respectively. Conclusion: POCUS outperformed CXR to predict positive NAT. POCUS could potentially replace other chest imaging for persons under investigation for COVID-19.

Influence of digital filtering parameters on the pulse waveform in reflectance photoplethysmography

Photoplethysmography (PPG) is an optical method for recording pulse wave (PW) propagating in the tissue microvasculature. As a rule, filters with infinite impulse response (Butterworth, Bessel, etc.) often used in PPG signal processing introduce distortions in the PW signal. At the same time, the filtering parameters for a more accurate reproduction of PW have not yet been substantiated. The aim of this work is to study the influence of digital filtering parameters, such as bandwidth and filter order, on the pulse waveform. In the study, a digital bandpass Butterworth filter was used. The lower cutoff frequency of the filter varied from 0.1 to 1 Hz, the upper cutoff frequency varied from 2 to 10 Hz and the filter order – from 2nd to 6th. It was found that an increase in the lower cutoff frequency of the bandpass filtering leads to a decrease in the amplitude of the reflected diastolic wave and distortion of the front of the direct systolic wave. A decrease in the upper cutoff frequency leads to damping of the dicrotic notch and a phase shift of the PW. Increasing the filter order decreases the reflected wave amplitude. The minimal distortions of the PPG signal were observed at the lower cutoff frequency of 0.1 Hz, the upper one at 10 Hz and the filter order equal to 2. Thus, these parameters of a bandpass filtering can be recommended for processing PPG signals for a more accurate morphological analysis of PW. The obtained results make it possible to create devices for PW analysis with substantiated medical and technical requirements for filtration parameters.

Oxygen torus and its coincidence with EMIC wave in the deep inner magnetosphere: Van Allen Probe B and Arase observations

We investigate the longitudinal structure of the oxygen torus in the inner magnetosphere for a specific event found on 12 September 2017, using simultaneous observations from the Van Allen Probe B and Arase satellites. It is found that Probe B observed a clear enhancement in the average plasma mass (M) up to 3–4 amu at L = 3.3–3.6 and magnetic local time (MLT) = 9.0 h. In the afternoon sector at MLT ~ 16.0 h, both Probe B and Arase found no clear enhancements in M. This result suggests that the oxygen torus does not extend over all MLT but is skewed toward the dawn. Since a similar result has been reported for another event of the oxygen torus in a previous study, a crescent-shaped torus or a pinched torus centered around dawn may be a general feature of the O+ density enhancement in the inner magnetosphere. We newly find that an electromagnetic ion cyclotron (EMIC) wave in the H+ band appeared coincidently with the oxygen torus. From the lower cutoff frequency of the EMIC wave, the ion composition of the oxygen torus is estimated to be 80.6% H+, 3.4% He+, and 16.0% O+. According to the linearized dispersion relation for EMIC waves, both He+ and O+ ions inhibit EMIC wave growth and the stabilizing effect is stronger for He+ than O+. Therefore, when the H+ fraction or M is constant, the denser O+ ions are naturally accompanied by the more tenuous He+ ions, resulting in a weaker stabilizing effect (i.e., larger growth rate). From the Probe B observations, we find that the growth rate becomes larger in the oxygen torus than in the adjacent regions in the plasma trough and the plasmasphere.

Optical and SHG Measurements of Aminoacids doped ADP NLO crystals

ABSTRACTL-Arginine and L-Alanine aminoacids doped ADP crystals were grown from aqueous solution by slow evaporation technique at constant temperature. The crystalline nature of the grown crystals was confirmed using powder X-ray diffraction technique. The vibrational frequencies of the grown crystals were identified using FTIR spectral analysis. Optical absorption study was carried out and a good transparency in the entire visible region was observed with the lower cutoff wavelength of 308 nm and 318 nm for the L-Alanine & L-Arginine doped crystals respectively. The transmission data has been used to evaluate the optical band gap of L-Alanine and L-Arginine doped ADP crystals and is found tobe 5.023 eV. Second harmonic generation (SHG) studies were performed by the classical Kurtz powder technique using a Nd: YAG laser operating at 1064 nm. The SHG efficiency of doped ADP is found to be higher compared to Pure ADP crystals.

Enhancement of yttrium ion on the properties of L-histidine nitrate single crystal for frequency conversion applications

Nonlinear optical single crystals of L-histidine nitrate (LHN) as well as 0.05 mol % Y2+ doped LHN and 0.10 mol % Y2+ doped LHN were successfully grown by slow evaporation technique at room temperature. The lower cutoff wavelength and transmittance were 339 nm, 343 nm, 347 nm and 84 %, 86 % and 87 % for LHN, 0.05 mol % and 0.10 mol % yttrium doped LHN, respectively. Powder XRD studies revealed that the grown materials belong to an orthorhombic system with the space group P212121. FT-IR peak at 534 cm−1 due to yttrium coordinated with oxygen was observed. The EDAX analysis confirmed the presence of such elements as C, N, O and Y in the grown materials. High intensity PL emission peak was obtained at 420 nm.

MoCA Test: normative and diagnostic accuracy data for seniors with heterogeneous educational levels in Brazil

ABSTRACT The Montreal Cognitive Assessment (MoCA) has been described as a good tool to detect cognitive impairment. The ideal MoCA cutoff score is still under debate. The aim was to provide MoCA norms and accuracy data for seniors with a lower education level, including illiterates. Methods: Data originated from an epidemiological study conducted in the municipality of Tremembe, Brazil. The Brazilian MoCA test was applied as part of the cognitive assessment in all participants. Of the 630 participants, 385 were classified as cognitively normal (CN) and were included in the normative data set, 110 individuals were diagnosed with dementia and 135 were classified as having cognitive impairment no dementia (CIND). Results: The total scores varied significantly according to age and education among the three diagnostic groups: CN, CIND and dementia (p < 0.001). To distinguish participants with CN from dementia, the best MoCA cutoff was 15 points (sensitivity 90%, specificity 77%) and to differentiate those with CN from CIND, the MoCA cutoff was 19 points (sensitivity 84%, specificity 49%). Those scores varied according to education level. Conclusions: The MoCA test did not have a high accuracy for detecting CIND in the population with a low educational level. Nevertheless, this tool may be used to detect dementia, especially in individuals with more than five years of education, if a lower cutoff score is adopted.