Exceptionally gigantic aurora in the polar cap on a day when the solar wind almost disappeared.

Revealing the origins of aurorae in Earth's polar cap has long been a challenge since direct precipitation of energetic electrons from the magnetosphere is not always expected in this region of open magnetic field lines. Here, we introduce an exceptionally gigantic aurora filling the entire polar cap region on a day when the solar wind had almost disappeared. By combining ground-based and satellite observations, we proved that this unique aurora was produced by suprathermal electrons streaming directly from the Sun, which is known as "polar rain." High-sensitivity imaging from the ground has visualized complex spatial structures of the polar rain aurora possibly manifesting the internal pattern of the solar wind or even the organizations in the chromosphere of the Sun.

Clinical features of sleep apnea syndrome and cognitive impairment in multiple sclerosis.

BACKGROUND: Complications of obstructive sleep apnea (OSA) have been reported in patients with multiple sclerosis (MS). Patients with sleep apnea syndrome (SAS) due to OSA also show cognitive decline, with similar clinical characteristics to that manifested in MS. SAS due to OSA is a treatable condition, and the associated cognitive decline is expected to improve. This study investigates clinical features of SAS in people living with MS and contribute to improve cognitive dysfunction of MS. METHODS: A case-control study was conducted. Cognitive functions were evaluated by the Symbol Digit Modalities Test (SDMT) and the Paced Auditory Serial Addition Test 2 (PASAT-2) and 3 (PASAT-3). The Respiratory Event Index (REI) was measured using Out of Center Sleep Testing (OCST). We defined subjects with REI ≥ 5 as OSA and divided participants into two groups with or without SAS due to OSA. Cognitive and respiratory characteristics were statistically compared between patients with MS and healthy controls. RESULTS: We enrolled 67 people living with MS and 31 age- and sex-matched controls. OCST detected OSA in people living with MS and controls, and the prevalence rates were 28.4 % and 25.8 %, respectively. REI values (5.2 ± 7.9 vs 3.9 ± 5.2, p = 0.509) and number of participants with REI ≥ 5 (19 vs 8, p = 0.793) were similar between the MS and control group. The SDMT, PASAT-2, and PASAT-3 scores were significantly lower in the MS group than the control group (p < 0.001, p = 0.001, and p < 0.001, respectively). The interaction effect of MS and SAS on cognitive function was not significant in the SDMT (p = 0.078), but in the PASAT-2 (p = 0.043) and PASAT-3 (p = 0.020). CONCLUSION: This study revealed the prevalence rates of SAS in Japanese people living with MS and the usefulness of OCST for detection of SAS. This study also revealed that concomitant SAS can facilitate cognitive decline in people living with MS. These findings suggest that an appropriate intervention for OSA can be beneficial for people living with MS with cognitive decline.

An automated auroral detection system using deep learning: real-time operation in Tromsø, Norway.

The activity of citizen scientists who capture images of aurora borealis using digital cameras has recently been contributing to research regarding space physics by professional scientists. Auroral images captured using digital cameras not only fascinate us, but may also provide information about the energy of precipitating auroral electrons from space; this ability makes the use of digital cameras more meaningful. To support the application of digital cameras, we have developed artificial intelligence that monitors the auroral appearance in Tromsø, Norway, instead of relying on the human eye, and implemented a web application, "Tromsø AI", which notifies the scientists of the appearance of auroras in real-time. This "AI" has a double meaning: artificial intelligence and eyes (instead of human eyes). Utilizing the Tromsø AI, we also classified large-scale optical data to derive annual, monthly, and UT variations of the auroral occurrence rate for the first time. The derived occurrence characteristics are fairly consistent with the results obtained using the naked eye, and the evaluation using the validation data also showed a high F1 score of over 93%, indicating that the classifier has a performance comparable to that of the human eye classifying observed images.

False-positive cases in multiple sleep latency test by accumulated sleep debt.

PURPOSE: Multiple sleep latency test (MSLT) is performed as objective assessment of sleepiness, on the following day after polysomnography (PSG). In most clinics, patients are required to stay for 2 days. However, if patients have chronic sleep debt before the examination, even if they get adequate nocturnal sleep during the initial PSG, their sleep debt would not be fully resolved, affecting MSLT results. This may lead to improper administration of psycho-stimulant medication. To clarify the sleep debt for the patients who showed short sleep latencies, we compared the mean sleep latencies of MSLTs. METHODS: Twelve hypersomnolent males, who underwent MSLTs (1st MSLT with 1 night and 2nd MSLT with more than 3 nights), were enrolled. We selected these cases based on the longer total sleep time on PSG night compared to the mean total sleep time on pre-examination sleep logs and shortened sleep latencies on PSG. To evaluate the effect of the sleep debt for the patients who showed short sleep latencies, we extended their hospitalization or re-hospitalized them. RESULTS: The mean sleep latency of 1st MSLT was 5.8 minutes and that of 2nd was 13.9 minutes (P < .001). Among these 12 cases, 5 cases altered from short to normal sleep latencies at the 2nd MSLT. These 5 cases were prevented from over-diagnoses by the extension of evaluations. CONCLUSIONS: The sleep debt may produce false-positive results when patients are examined by standard PSG and MSLT. Accumulation of sleep debt will cause shortened sleep latencies in the following nights. Patients should be advised to extend their hospitalization before PSG and MSLT to reduce the chronic sleep debt for accurate diagnosis of hypersomnia.

Visualization of rapid electron precipitation via chorus element wave-particle interactions.

Chorus waves, among the most intense electromagnetic emissions in the Earth's magnetosphere, magnetized planets, and laboratory plasmas, play an important role in the acceleration and loss of energetic electrons in the plasma universe through resonant interactions with electrons. However, the spatial evolution of the electron resonant interactions with electromagnetic waves remains poorly understood owing to imaging difficulties. Here we provide a compelling visualization of chorus element wave-particle interactions in the Earth's magnetosphere. Through in-situ measurements of chorus waveforms with the Arase satellite and transient auroral flashes from electron precipitation events as detected by 100-Hz video sampling from the ground, Earth's aurora becomes a display for the resonant interactions. Our observations capture an asymmetric spatial development, correlated strongly with the amplitude variation of discrete chorus elements. This finding is not theoretically predicted but helps in understanding the rapid scattering processes of energetic electrons near the Earth and other magnetized planets.

Decrease of Plasma Soluble (Pro)renin Receptor by Bariatric Surgery in Patients with Obstructive Sleep Apnea and Morbid Obesity.

BACKGROUND: Plasma concentrations of soluble (pro)renin receptor [s(P)RR], which are elevated in patients with obstructive sleep apnea (OSA), have not been studied in morbid obesity. The aim of this study is to clarify effects of bariatric surgery on plasma s(P)RR concentrations and identify associated factors for their changes in OSA patients with morbid obesity. METHODS: Twenty-three patients with OSA complicated by morbid obesity (10 men and 13 women; body mass index, 40.7 ± 6.16 kg/m2) without chronic kidney disease were followed up after bariatric surgery. Overnight polysomnography (PSG) was performed before surgery, and 4 and 24 weeks after surgery. Plasma s(P)RR concentrations were measured each morning after PSG. RESULTS: Preoperative plasma s(P)RR concentrations showed significant positive correlations with serum creatinine (P < 0.05), arousal index (P < 0.01), apnea-hypopnea index (AHI) (P < 0.05), apnea index (P < 0.005), and desaturation index (P < 0.05), and a significant inverse correlation with an estimated glomerular filtration rate (P < 0.05). With the improvement of these PSG parameters, plasma s(P)RR concentrations significantly decreased from 15.3 ± 3.6 to 12.5 ± 2.7 ng/mL 4 weeks after surgery, which further decreased to 11.4 ± 2.4 ng/mL 24 weeks after surgery. The association observed before surgery between plasma s(P)RR concentrations and the PSG parameters was not seen after surgery. CONCLUSIONS: Bariatric surgery in patients with OSA complicated by morbid obesity decreased plasma s(P)RR concentrations. The most associated factors for their changes were arousal index, AHI, apnea index, and desaturation index.

Prevalence of sleep-disordered breathing in Japanese medical students based on type-3 out-of-center sleep test.

BACKGROUND: Sleep-disordered breathing (SDB), especially obstructive sleep apnea disorder (OSA), is thought to mainly affect men over the age of 40. Following findings that Asian people are more likely to experience severe OSA, regardless of obesity, we investigated the prevalence of SDB and OSA in a larger sample and in more younger age groups than those described in previous reports. METHODS: Between 2011 and 2016, 487 medical students (358 males, mean age 24.8 ± 1.9 years; 129 females: mean age 23.8 ± 1.6 years) underwent an out-of-center sleep test using a type-3 portable monitor. The results were analyzed visually. RESULTS: The mean ± standard deviation of the respiratory event index (REI: events/hour of monitoring) was 5.4 ± 6.7 (6.7 ± 7.5 in male participants, 2.6 ± 2.1 in female participants). There were 170 participants (36.6%) with an REI≥5, including 158 male participants (46.9%) and 12 female participants (9.1%). SDB or undefined OSA with low REI (15 > REI≥5) was observed in 141 participants (30.4%), defined OSA with moderate REI (30 > REI≥15) in 19 participants (4.1%), and defined OSA with high REI (REI≥30) in 10 participants (2.2%). Among the male students, 129 had low REI (38.3%), 19 had moderate REI (5.6%), and 10 had high REI (3.0%). All female participants with OSA events (9.4%) had a low REI. CONCLUSIONS: The prevalence of OSA in Japanese young adults, especially males under 30 years old, is similar or even higher than that in older age groups described previously. Thus, an aggressive sleep study for SDB might be necessary for the younger generation in the Asian population.

Auroral molecular-emission effects on the atomic oxygen line at 777.4 nm.

One of the representative auroral emission lines that radiates from F-region heights and is measurable on the ground is the 777.4 nm line from excited atomic oxygen. This line has been adopted, along with another E-region emission line, for example 427.8 nm, to estimate the mean energy and total energy flux of precipitating auroral electrons. The influence of emissions from part of the molecular nitrogen band, which mainly radiate from E-region heights, should be carefully evaluated because it might overlap the 777.4 nm atomic oxygen line in the spectrum. We performed statistical analysis of auroral spectrograph measurements that were obtained during the winter of 2016-2017 in Tromsø, Norway, to derive the ratio of the intensity of the 777.4 nm atomic oxygen line to that of the net measurement through a typically used optical filter with a full width at half maximum of a few nm. The ratio had a negative trend against geomagnetic activity, with a primary distribution of 0.5-0.7 and a minimum value of 0.3 for the most active auroral condition in this study. This result suggests that the 30-50% emission intensities measured through the optical filter may be from the molecular nitrogen band.

Tamoxifen-induced Lung Injury.

Cases of drug-induced lung injury caused by tamoxifen are rare. A 74-year-old man underwent surgery for the treatment of right breast cancer; tamoxifen was administered as an adjuvant therapy after surgery. The patient developed cough and dyspnea and chest computed tomography showed ground glass opacification in the lower lobe of the right lung. He was diagnosed with tamoxifen-induced lung injury. The diagnosis was made based on the exclusion of other causes and recurrence with the re-administration of tamoxifen. Physicians should therefore be aware of the potential for the development of tamoxifen-induced lung injury.

Elevated Plasma Levels of Soluble (Pro)Renin Receptor in Patients with Obstructive Sleep Apnea Syndrome in Parallel with the Disease Severity.

(Pro)renin receptor ((P)RR), a receptor for renin and prorenin, is implicated in the pathophysiology of diabetes mellitus, hypertension and their complications. Soluble (P)RR (s(P)RR) is composed of extracellular domain of (P)RR and thus exists in blood. We have reported that plasma concentrations of s(P)RR were elevated in male patients with obstructive sleep apnea syndrome (OSAS). The aim of the present study was to clarify the difference in plasma s(P)RR concentrations between male and female OSAS patients. Plasma s(P)RR concentrations were studied in 289 subjects (206 males and 83 females) consisting of 259 OSAS patients and 30 non-OSAS control subjects. The 259 OSAS patients were classified into mild (5 ≤ apnea hypopnea index (AHI) < 15 events/h), moderate (15 ≤ AHI < 30), and severe OSAS (AHI ≥ 30). Plasma s(P)RR levels were significantly elevated in all three OSAS groups compared to non-OSAS control subjects (AHI < 5) in the entire cohort and male subjects, whereas in female subjects, the significant elevation was found only in severe OSAS. Plasma s(P)RR levels were significantly correlated with AHI in both sexes, with a higher r value found in male subjects (male r = 0.413, p < 0.0001; female r = 0.263, p < 0.05). Importantly, when OSAS patients (26 males and 15 females) with AHI ≥ 20 underwent continuous positive airway pressure treatment, plasma s(P)RR levels were significantly decreased. In conclusion, plasma s(P)RR levels are elevated in both male and female OSAS patients in parallel with the disease severity.

Transcutaneous carbon dioxide during sleep-disordered breathing.

Respiratory drive is tightly controlled by the carbon dioxide levels. We tested the hypothesis that sequences of sleep apnoea (obstructive, central or mixed), hypopnoea and flow limitation are characterized by different levels of transcutaneous CO2 (PtcCO2). Polygraphic recordings (n=555) from patients with suspected sleep-disordered breathing (SDB) were retrospectively screened to find sequences (5 min or 10 events) of both SDB and steady breathing. Eighty-eight SDB sequences from 44 patients were included and PtcCO2 and SpO2 values were collected. PtcCO2 values during sequences were normalized by setting wakefulness level as 100%. In terms of PtcCO2, apnoea sequences with central component (central (n=7) and mixed (n=3) apnoea) did not differ from wakefulness (102.0% vs 100%, p=0.122) whereas obstructive apnoea (105.8%, p<0.001) and hypopnoea did (105.4%, p<0.001). PtcCO2 during flow limitation was higher than that during any other sequence, including steady breathing (112.2% vs 108.4%, p=0.022). Continuous PtcCO2 monitoring during sleep adds to the understanding of different SDB phenotypes.

Effects of CPAP treatment interruption due to disasters: patients with sleep-disordered breathing in the Great East Japan Earthquake and tsunami area.

INTRODUCTION: The 2011 Great East Japan Earthquake caused major disruptions in the provision of health care, including that for patients with sleep-disordered breathing (SDB) using a nasal continuous positive airway pressure (nCPAP) device. This study investigated the ability of SDB patients to continue using the nCPAP device in the weeks immediately following the earthquake, whether inability to use the nCPAP device led to symptom relapse, and measures that should be taken to prevent disruptions in nCPAP therapy during future disasters. Hypothesis If nCPAP devices cannot be used during disasters, SDB patients' health will be affected negatively. METHODS: Within 14 days of the disaster, 1,047 SDB patients completed a questionnaire that collected data regarding ability to use, duration of inability to use, and reasons for inability to use the nCPAP device; symptom relapse while unable to use the nCPAP device; ability to use the nCPAP device use at evacuation sites; and recommendations for improvement of the nCPAP device. RESULTS: Of the 1,047 patients, 966 (92.3%) had been unable to use the nCPAP device in the days immediately following the earthquake. The most common reason for inability to use the nCPAP device was power failure, followed by anxiety about sleeping at night due to fear of aftershocks, involvement in disaster-relief activities, loss of the nasal CPAP device, and fear of being unable to wake up in case of an emergency. Among the 966 patients, 242 (25.1%) had experienced relapse of symptoms, the most common of which was excessive daytime sleepiness (EDS), followed by insomnia, headache, irritability, and chest pain. CONCLUSION: Developing strategies for the continuation of nCPAP therapy during disasters is important for providing healthy sleeping environments for SDB patients in emergency situations.