20 research outputs found
Design of 6U Nanosatellites in Formation Flying for the Laser Crosslink Mission
With a recent growth in the volume of spaceborne data, free space optical (FSO) or laser communication systems are attracting attention, as they can enable super-high data rates faster than 1 Gbps. The Very high-speed Inter-satellite link Systems using Infrared Optical terminal and Nanosatellite (VISION) is a technical demonstration mission to establish and validate laser crosslink systems using two 6U nanosatellites in formation flying. The final goal is to achieve a Gbps-level data rate at a distance of thousands of kilometers. To establish space-to-space laser communication, the payload optical axes of each satellite should be precisely aligned during the crosslink. The payload is the laser communication terminal (LCT) including the deployable space telescope (DST), which improves optical link performances. The 6U nanosatellite bus is designed with commercial off-the shelf-(COTS) components for agile systems development. For precise formation flying, the bus is equipped a with relative navigation system with a GNSS receiver and RF crosslink, star tracker, 3-axis reaction wheels (RWs), and propulsion system. This proposed concept of the laser crosslink systems will contribute to the construction of the LEO communication constellation with high speed and secure links in future
Shift schedules and circadian preferences: the association with sleep and mood
ObjectWe explored the circadian preferences of non-shift workers (non-SWs) and various types of shift workers (SWs), and the associations of these preferences with sleep and mood.MethodsIn total, 4,561 SWs (2,419 women and 2,142 men aged 37.00 ± 9.80 years) and 2,093 non-SWs (1,094 women and 999 men aged 37.80 ± 9.73 years) completed an online survey. Of all SWs, 2,415 (1,079 women and 1,336 men aged 37.77 ± 9.96 years) reported regularly rotating or fixed schedules (“regular SWs”), and 2,146 (1,340 women and 806 men aged 36.12 ± 9.64 years) had irregular schedules (“irregular SWs”). Of the regular SWs, 2,040 had regularly rotating schedules, 212 had fixed evening schedules, and 163 had fixed night schedules. All participants completed the Morningness-Eveningness Questionnaire (MEQ) exploring circadian preferences, the short form of the Center for Epidemiological Studies-Depression Scale (CES-D) evaluating depression, the Insomnia Severity Index (ISI), and the Epworth Sleepiness Scale (ESS).ResultsCompared to non-SWs, SWs had lower MEQ scores, i.e., more eveningness, after controlling for age, gender, income, occupation, and weekly work hours (F = 87.97, p < 0.001). Irregular SWs had lower MEQ scores than regular SWs (F = 50.89, p < 0.001). Among regular SWs, the MEQ scores of fixed evening and fixed night SWs were lower than those of regularly rotating SWs (F = 22.42, p < 0.001). An association between the MEQ and ESS scores was apparent in non-SWs (r = −0.85, p < 0.001) but not in SWs (r = 0.001, p = 0.92).ConclusionSWs exhibited more eveningness than non-SWs; eveningness was particularly prominent in SWs with irregular or fixed evening/night shifts. Eveningness was associated with sleepiness only in non-SWs, but not in SWs
Sleep disturbances, depressive symptoms, and cognitive efficiency as determinants of mistakes at work in shift and non-shift workers
IntroductionShift work is known to reduce productivity and safety at work. Previous studies have suggested that a variety of interrelated factors, such as mood, cognition, and sleep, can affect the performance of shift workers. This study aimed to identify potential pathways from depression, sleep, and cognition to work performance in shift and non-shift workers.Material and methodsOnline survey including the Center for Epidemiologic Studies Depression Scale (CES-D), Cognitive Failure Questionnaire (CFQ), and Pittsburgh Sleep Quality Index (PSQI), as well as two items representing work mistakes were administered to 4,561 shift workers and 2,093 non-shift workers. A multi-group structural equation model (SEM) was used to explore differences in the paths to work mistakes between shift and non-shift workers.ResultsShift workers had higher PSQI, CES-D, and CFQ scores, and made more mistakes at work than non-shift workers. The SEM revealed that PSQI, CES-D, and CFQ scores were significantly related to mistakes at work, with the CFQ being a mediating variable. There were significant differences in the path coefficients of the PSQI and CES-D between shift and non-shift workers. The direct effects of sleep disturbances on mistakes at work were greater in shift workers, while direct effects of depressive symptoms were found only in non-shift workers.DiscussionThe present study found that shift workers made more mistakes at work than non-shift workers, probably because of depressed mood, poor sleep quality, and cognitive inefficiency. Sleep influences work performance in shift workers more directly compared to non-shift workers
Effects of driving style and bedding in pigs transported to slaughterhouse in different temperatures
Animal welfare during transport became an largely issue because of increasing demand for improved animal welfare standards. Most studies on the animal welfare during transportation have concentrated on the atmosphere and the temperature of the truck compartments. Thus, the objective of study was to collect and quantify three axis acceleration and determine the effect of bedding for transporting pigs from farm to slaughterhouse. A total of 2,840 crossbred fattening pigs with a live weight of approximately 115 kg were used. They were raised in the same commercial farms and transported to the same commercial slaughterhouse. A 3×2×2 completely randomized factorial design was used to investigate effects of rubber type bedding (bedding or non-bedding) and two levels of driving style (aggressive or normal) in three different time periods with different outside temperatures. Air temperature treatments were as follow: high temperature ([HT] higher than 24°C); low temperature ([LT] lower than 10°C); normal temperature ([NT] 10°C to 24°C). In our experiment, pigs transported under aggressive driving style showed lower (p < 0.05) pH and water holding capacity (WHC) than those transported under normal driving style. Pigs transported under normal driving style showed a lower percentage of drip loss (DL) (p < 0.05) than those transported with an aggressive driving style. Also, transported with bedding showed higher (p < 0.05) lying behavior but lower (p < 0.05) sitting behavior than those transported without bedding. Pigs transported under normal driving style showed lower (p < 0.05) cortisol level than those transported under aggressive driving style. In conclusion, aggressive driving style cause acute stress in pigs, while bedding helps alleviate acute stress in pigs during transportation in LT
Brain structural correlates of subjective sleepiness and insomnia symptoms in shift workers
BackgroundStudies on the brain structures of shift workers are limited; thus, this cross-sectional study aimed to compare the brain structures and the brain structural correlates of subjective sleepiness and insomnia symptoms between shift workers and non-shift workers.MethodsShift workers (n = 63) and non-shift workers (n = 58) completed questionnaires assessing subjective sleepiness and insomnia symptoms. Cortical thickness, cortical surface area, and subcortical volumes were measured by magnetic resonance imaging. The brain morphometric measures were compared between the groups, and interaction analyses using the brain morphometric measures as the dependent variable were performed to test the interactions between the study group and measures of sleep disturbance (i.e., subjective sleepiness and insomnia symptoms).ResultsNo differences in cortical thickness, cortical surface area, or subcortical volumes were detected between shift workers and non-shift workers. A single cluster in the left motor cortex showed a significant interaction between the study group and subjective sleepiness in the cortical surface area. The correlation between the left motor cortex surface area and the subjective sleepiness level was negative in shift workers and positive in non-shift workers. Significant interaction between the study group and insomnia symptoms was present for the left/right putamen volumes. The correlation between the left/right putamen volumes and insomnia symptom levels was positive in shift workers and negative in non-shift workers.ConclusionLeft motor cortex surface area and bilateral putamen volumes were unique structural correlates of subjective sleepiness and insomnia symptoms in shift workers, respectively
Prognostic Value of Functional Assessment of Cancer Therapy-General (FACT-G) in Advanced Non-Small-Cell Lung Cancer Treated with Korean Medicine
Objectives. The impact of health-related quality of life (HRQoL) on survival has been investigated in patients with various cancers. Here, we evaluated the prognostic value of HRQoL using the Functional Assessment of Cancer Therapy-General (FACT-G) in advanced non-small-cell lung cancer (NSCLC) patients treated with Korean medicine. Methods. A retrospective review of medical records and FACT-G scores of patients with advanced NSCLC who received treatment with Korean medicine was conducted. The reliability of the FACT-G was determined using Cronbach’s alpha and calculating floor-and-ceiling effects. Correlations between FACT-G scores were estimated using Pearson’s correlation analysis. Overall survival was calculated using the Kaplan–Meier method, and the prognostic impact of FACT-G scores and patients’ characteristics was evaluated with Cox proportional hazards regression. Results. Of the 165 enrolled patients, 115 (70%) had extrathoracic metastasis and 139 (84%) had undergone prior anticancer treatment. The median overall survival was 10.1 months. The mean FACT-G score was 65.0, and Cronbach’s alpha for the FACT-G was 0.917. Age ≥65 years, male sex, smoking history, squamous-cell carcinoma, Eastern Cooperative Oncology Group Performance Status (ECOG-PS) ≥2, and presence of extrathoracic metastasis were associated with an increased risk of mortality. High FACT-G total scores, physical well-being (PWB), emotional well-being, and functional well-being were associated with prolonged survival. After adjusting for age, sex, smoking history, ECOG-PS, histological type, and presence of extrathoracic metastasis, a high FACT-G total score (hazard ratio (HR): 0.99, p=0.032) and high PWB score (HR: 0.94, p<0.001) were associated with prolonged survival as independent prognostic factors in patients with advanced NSCLC. Conclusion. The FACT-G total score and PWB score as HRQoL measurements were significant prognostic factors for survival in advanced NSCLC patients treated with Korean medicine. This finding implies that the FACT-G can be used in clinical practice as a predictor of survival in patients with advanced NSCLC
Exposure to Traffic-Related Particulate Matter 2.5 Triggers Th2-Dominant Ocular Immune Response in a Murine Model
Ambient particulate matter (PM), a major component of air pollution, aggravates ocular discomfort and inflammation, similarly to dry eye disease (DED) or allergies. However, the mechanism(s) by which PM induces the ocular inflammatory response is unknown. This study investigated the immunological response of traffic-related fine particulate matter (PM2.5) on the ocular surface in a murine model. C57BL/6 mice were exposed by topical application to PM2.5 or vehicle for 14 days to induce experimental environmental ocular disease. Corneal fluorescein staining and the number of ocular inflammatory cells were assessed in both groups. The expression of IL-1β, IL-6, tumor necrosis factor (TNF)-α, and mucin 5AC (MUC5AC) in the ocular surface were evaluated by real-time PCR. An immunohistochemical assay evaluated apoptosis and goblet cell density. ELISA was used to determine the levels of serum IgE and cytokines of Type 1 helper (Th1) and Type 2 helper (Th2) cells after in vitro stimulation of T cells in the draining lymph nodes (LNs). Exposure to traffic-related PM2.5 significantly increased corneal fluorescein staining and cellular toxicity in the corneal epithelium compared with the vehicle control. A significant increase in the number of CD11b+ cells on the central cornea and mast cells in the conjunctiva was observed in the PM2.5 group. Exposure to PM2.5 was associated with a significant increase in the corneal or conjunctival expression of IL-1β, IL-6, TNF, and MUC5AC compared to the vehicle, and increased maturation of dendric cells (DCs) (MHC-IIhighCD11c+) in draining LNs. In addition, PM2.5 exposure increased the level of serum IgE and Th2 cytokine production in draining LNs on day 14. In conclusion, exposure to traffic-related PM2.5 caused ocular surface damage and inflammation, which induced DC maturation and the Th2-cell-dominant allergic immune response in draining LNs
The Effectiveness of Cognitive Behavioral Therapy on Depressive Symptoms in North Korean Refugees
Objective Despite the growing need for psychological programs for North Korean refugees, most psychological interventions for these people lack a verification study that tests their effectiveness. This study aims to evaluate the effectiveness of cognitive behavioral therapy (CBT) in North Korean refugees. Methods Participants included 38 North Korean refugees, of whom 23 participated in simple relaxation and 15 participated in CBT. The Korean version of the Center for Epidemiologic Studies Depression Scale (CES-D), State-Trait Anxiety Inventory-State (STAI-S), and Impact of Event Scale-Revised were used to evaluate symptoms pre- and post-intervention. Results Participants had a significant decrease in CES-D scores after treatment (p=0.037). The decrease in CES-D was larger in those who participated in the CBT compared to those in simple relaxation (p=0.023). The superior effects that CBT had on depressive symptoms over simple relaxation were particularly more prominent in those with severe depression (p=0.035). Participants with high levels of anxiety also showed significant decreases in STAI-S scores after treatment, regardless of which type of program they participated in (p=0.023). Conclusion This preliminary findings suggests that CBT is an effective psychiatric approach in treating depressive symptoms in North Korean refugees, especially for those with a higher degree of depressive symptom.Y
Polysomnographic Sleep and Attentional Deficits in Traumatized North Korean Refugees
Introduction: Attentional deficits and sleep problems are common in refugees who have experienced trauma. In the present study, we used polysomnography (PSG) to investigate the relationship between attentional deficits and objective measures of sleep structure in traumatized North Korean refugees.Methods: We recruited 32 North Korean refugees (mean age = 33.78 ± 14.33 years) and 39 South Korean participants (mean age = 35.03 ± 11.08 years). Sustained attention and divided attention were assessed using the Computerized Attention Test. We conducted an overnight PSG to objectively assess sleep structure. The participants also completed the Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), Impact of Event Scale-Revised (IES-R), Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Insomnia Severity Index (ISI).Results: The North Korean refugees showed more commission errors (CEs, p Conclusion: The North Korean refugees showed poorer performance on the sustained attention task. Nocturnal PSG revealed shorter WASO and time spent in N1 in this population, which are independently associated with the preservation of attentional capacity. These data suggest that traumatized refugees may compensate for attentional deficits induced by their traumatic experiences via increased sleep continuity.publishe