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The assessment of information transfer in the global economic network helps to understand the current environment and the outlook of an economy. Most approaches on global networks extract information transfer based mainly on a single variable. This paper establishes an entirely new bioinformatics-inspired approach to integrating information transfer derived from multiple variables and develops an international economic network accordingly. In the proposed methodology, we first construct the transfer entropies (TEs) between various intra- and inter-country pairs of economic time series variables, test their significances, and then use a weighted sum approach to aggregate information captured in each TE. Through a simulation study, the new method is shown to deliver better information integration compared to existing integration methods in that it can be applied even when intra-country variables are correlated. Empirical investigation with the real world data reveals that Western countries are more influential in the global economic network and that Japan has become less influential following the Asian currency crisis.

Abstract Torpor and arousal cycles, both daily and seasonal (e.g. hibernation), are crucial for small mammals, including bats, to maintain the energy and water balance. The alternation between torpor and arousal leads to metabolic changes, leaving traceable evidence of metabolic wastes in urine. In this study we investigated urinary creatinine and acetoacetate (a ketone body) in the Eastern bent-wing bat (Miniopterus fuliginosus) in Mungyeong, South Korea. We found an increase in urinary creatinine during torpor in summer, indicating changes in renal water reabsorption rates during the active season. Although we could not confirm ketonuria in hibernating bats due to a methodological limitation caused by the small amount of urine, we verified an increase in urinary creatinine concentration during hibernation. This finding suggests that managing water stress resulting from evaporative water loss is one of key reasons for arousal during hibernation in Eastern bent-wing bats.

Summary: Background: In Korea, the need for bariatric surgery (BS) is increasing because of the increasing incidence of morbid obesity. There is no special training program for BS, and most BS are conducted in non-tertiary hospitals in capital area. We evaluated the surgical outcomes of laparoscopic sleeve gastrectomy (LSG) before and after the learning curve (LC) to prove that the barrier of entry for LSG is not very high. Methods: We retrospectively analyzed the data of patients who underwent LSG in a secondary hospital without the supervision of an experienced surgeon between April 2019 and August 2022. We compared the surgical outcomes and changes in body measurements before the LC (BL) and after the LC (AL) after 1 year of follow-up. Results: The duration of operation for BL and AL were 118.4 and 61.9 min (p = 0.000), respectively. No mortality was observed. There were four and eight cases of morbidity; the weight loss after 1 year was 90.6 and 89.7 kg (p = 0.804); changes in body mass index (BMI) were 10.3 and 10.2 kg/m2 (p = 0.928); excess weight loss after 1 year was 93.0 and 89.3% (p = 0.762); and excess BMI loss after 1 year was 92.7 and 89.5% (p = 0.807) in the BL and AL groups, respectively. %Total weight loss was 26.8 and 23.7 in the BL and AL group. There was no statistical significance of all parameters of body measurements between two groups. Conclusion: LSG can be safely and effectively performed by novice bariatric surgeons in non-tertiary hospitals if patients are cautiously selected. Surgical outcomes of BL and AL is not different, except for the operation time.

Abstract Background Prehospital factors play a vital role in out-of-hospital cardiac arrest (OHCA) survivability, and they vary between countries and regions. We investigated the prehospital factors associated with OHCA outcomes in a single metropolitan city in the Republic of Korea. Methods This study included adult medical OHCA patients enrolled prospectively, using data from the citywide OHCA registry for patients registered between 2018 and 2021. The primary outcome was survival to hospital discharge. Multivariable logistic regression analysis was conducted to determine the factors associated with the study population’s clinical outcomes, adjusting for covariates. We performed a sensitivity analysis for clinical outcomes only for patients without prehospital return of spontaneous circulation prior to emergency medical service departure from the scene. Results In multivariable logistic regression analysis, older age (odds ratio [OR] 0.96; 95% confidence interval [CI] 0.95–0.97), endotracheal intubation (adjusted odds ratio [aOR] 0.29; 95% [CIs] 0.17–0.51), supraglottic airway (aOR 0.29; 95% CI 0.17–0.51), prehospital mechanical chest compression device use (OR 0.13; 95% CI 0.08–0.18), and longer scene time interval (OR 0.96; 95% CI 0.93–1.00) were negatively associated with survival. Shockable rhythm (OR 24.54; 95% CI 12.99–42.00), pulseless electrical activity (OR 3.11; 95% CI 1.74–5.67), and witnessed cardiac arrest (OR 1.59; 95% CI 1.07–2.38) were positively associated with survival. In the sensitivity analysis, endotracheal intubation, supraglottic airway, prehospital mechanical chest compression device use, and longer scene time intervals were associated with significantly lower survival to hospital discharge. Conclusions Regional resuscitation protocol should be revised based on the results of this study, and modifiable prehospital factors associated with lower survival of OHCA should be improved.

Bats serve as vectors and natural reservoir hosts for various infectious viruses, bacteria, and fungi. These pathogens have also been detected in bat feces and can cause severe illnesses in hosts, other animals, and humans. Because pathogens can easily spread into the environment through bat feces, determining the bacterial communities in bat guano is crucial to mitigate potential disease transmission and outbreaks. This study primarily aimed to examine bacterial communities in the feces of insectivorous bats living in South Korea. Fecal samples were collected after capturing 84 individuals of four different bat species in two regions of South Korea, and the bacterial microbiota was assessed through next generation sequencing of the 16S rRNA gene. The results revealed that, with respect to the relative abundance at the phylum level, Myotis bombinus was dominated by Firmicutes (47.24%) and Proteobacteria (42.66%) whereas Miniopterus fuliginosus (82.78%), Rhinolophus ferrumequinum (63.46%), and Myotis macrodactylus (78.04%) were dominated by Proteobacteria. Alpha diversity analysis showed no difference in abundance between species and a significant difference (p < 0.05) between M. bombinus and M. fuliginosus. Beta-diversity analysis revealed that Clostridium, Asaia, and Enterobacteriaceae_g were clustered as major factors at the genus level using principal component analysis. Additionally, linear discriminant analysis effect size was conducted based on relative expression information to select bacterial markers for each bat species. Clostridium was relatively abundant in M. bombinus, whereas Mycoplasma_g10 was relatively abundant in R. ferrumequinum. Our results provide an overview of bat guano microbiota diversity and the significance of pathogenic taxa for humans and the environment, highlighting a better understanding of preventing emerging diseases. We anticipate that this research will yield bioinformatic data to advance our knowledge of overall microbial genetic diversity and clustering characteristics in insectivorous bat feces in South Korea.

Background To prepare for future work stoppages in the medical industry, this study aimed to identify the effects of healthcare worker strikes on the mortality rate of patients visiting the emergency department (ED) at six training hospitals in Daegu, South Korea. Methods We used a retrospective, cross-sectional, multicenter design to analyze the medical records of patients who visited six training hospitals in Daegu (August 21–September 8, 2020). For comparison, control period 1 was set as the same period in the previous year (August 21–September 8, 2019) and control period 2 was set as July 1–19, 2020. Patient characteristics including age, sex, and time of ED visit were investigated along with mode of arrival, length of ED stay, and in-hospital mortality. The experimental and control groups were compared using t-tests, and Mann-Whitney U-test, chi-square test, and Fisher exact tests, as appropriate. Univariate logistic regression was performed to identify significant factors, followed by multivariate logistic regression analysis. Results During the strike period, 31,357 patients visited the ED, of which 7,749 belonged to the experimental group. Control periods 1 and 2 included 13,100 and 10,243 patients, respectively. No significant in-hospital mortality differences were found between strike periods; however, the results showed statistically significant differences in the length of ED stay. Conclusion The ED resident strike did not influence the mortality rate of patients who visited the EDs of six training hospitals in Daegu. Furthermore, the number of patients admitted and the length of ED stay decreased during the strike period.

Photoconductive semiconductor switch (PCSS) allowing side illumination was fabricated on high purity semi-insulating (HPSI) 4H-SiC. A 532-nm pulsed laser with variable optical energy was used to trigger the PCSS. The performance of the PCSS was characterized under the two different load conditions, 50- $\Omega $ load and 0.05- $\Omega $ , with a current viewing resistor (CVR). The PCSS exhibited significantly different output characteristics for the two different loads. The equivalent resistance of the PCSS with the 50- $\Omega $ load, which was calculated from the output voltage and current, was inversely proportional to the optical energy, but the one with a 0.05- $\Omega $ load exhibited saturation behavior with the optical energy. While the times at peak output with the 50- $\Omega $ load were similar at various optical energies, the times at peak output with the 0.05- $\Omega $ load were dependent on the optical energy. Output current oscillation was also observed after the PCSS was turned off in the case of 0.05- $\Omega $ load condition. The different output characteristics for the different load resistances were analyzed using the transient response of the equivalent circuits. The PCSS exhibited a minimum on-state resistance of $0.27~\Omega $ with the optical energy of 8 mJ and a maximum output current of 657 A at the bias voltage of 4.8 kV. The operating voltage of the PCSS was limited by surface flashover, which caused an additional output pulse following the first output pulse.

Epidural hematoma with Brown-Sequard syndrome caused by an epidural injection is a rarely found condition in the emergency department (ED). We report an unusual case of Brown-Sequard syndrome in a 55-year-old man who presented at the ED with right-sided weakness and contralateral loss of pain and temperature sensation after a cervical epidural injection for shoulder pain. Cervicla spine magnetic resonance imaging showed an epidural hematoma from C4 to C6. After admission, his right hemiparesis and contralateral sensory loss improved within eight days, and surgical decompression was not required. Diagnosing spinal lesions in the ED is challenging, especially in patients with acute neurological signs requiring immediate evaluation for stroke. In this case, definite hemiparesis and some contralateral sensory loss were noted. Therefore, a potential spinal lesion was suspected rather than a stroke. This case emphasized the importance of conducting a focused neurological examination after history taking.

Motorcycles are widely used in various workplaces. Motorcycle use for occupational purposes continues to increase owing to growing e-commerce. Here, we aimed to highlight the importance of occupational motorcycle injuries by analyzing their epidemiologic characteristics and outcomes. We analyzed retrospective data from the Emergency Department-based Injury In-depth Surveillance program from 2012 to 2018. Motor vehicle injuries involving riders aged ≥16 years were included. Patients were divided into occupational motorcycle and non-occupational motorcycle injury groups based on whether or not the injury occurred during work time. General characteristics, injury details, and clinical outcomes such as injury severity and in-hospital mortality were analyzed. Of the 37,194 study patients, 24.2% (8,991) experienced occupational motorcycle injuries. The number of injuries in both groups increased yearly, as did the proportion of occupational injuries among total injuries. In both the groups, patients aged 20-29 years had the highest proportion of injuries. Regarding collision pattern and injury counterpart, side-to-side collisions and injuries involving small four-wheel vehicles were the most frequent. Alcohol intake was significantly lower, while helmet usage was higher in the occupational motorcycle injury group. Moreover, patients with occupational motorcycle injuries had lower injury severity, admission rate, and in-hospital mortality. On multivariable logistic regression analysis, increasing age, time of the injury, alcohol intake, not using a helmet, and collision with a human or animal were associated with higher odds of severe injury. Patients with occupational injuries had higher helmet usage, lower injury severity, lower mortality, and lower admission rate than did patients with non-occupational injuries. Injury severity was associated with the time of injury, collision with other living objects, alcohol consumption, and helmet usage.

The Gangwon-do Province in Korea features abundant limestone areas and numerous limestone caves; however, few studies have conducted systematic research on the limestone caves in this area. In this study, we observed and explored the biota of three undisclosed caves located in Pyeongchang-gun, Gangwon-do Province (Jangamgul Cave, Baramgul Cave, and Ssanggul Cave) to further understand their ecology. As a result, a total of four phyla, 12 classes, 30 orders, 77 families, and 125 species of cave organisms were discovered, including three phyla, 11 classes, 23 orders, 51 families, and 77 species in Jangamgul Cave; four phyla, 10 classes, 23 orders, 43 families, and 52 species in Baramgul Cave; and three phyla, nine classes, 20 orders, 41 families, and 54 species in Ssanggul Cave. Several threatened species such as Plecotus auritus (Linnaeus, 1758), designated as Class 2 endangered wildlife in Korea, Onychodactylus fischeri (Boulenger, 1886), designated as a least concern (LC) species by the IUCN, and Galloisiana sp., described as an extant species of the relict insect were found in this study. Our results are significant in providing information on the distribution of cave organisms living by adapting to the cave environment.

We report a new device design of a graphene field-effect transistor (G-FET) for capacitive sensing application. A channel area exposed to ambient conditions in G-FET is known to be a promising candidate for molecular level sensing applications because graphene can attract certain molecules with its freely hanging sigma bonds. In addition, molecules that adhere to graphene act as impurities that affect the electron transport within graphene. Two of the most common ways to evaluate such a change are measuring the changes in resistance and in quantum capacitance. Previous research studies have been largely focused on using resistive measurement due to restrictions from device design even though capacitive measurement can be cost-effective. To overcome the obstacles, we developed G-FET with high capacitance and a large exposed channel area by incorporating Al back-gate electrodes with naturally oxidized AlOx surface as an insulating layer. The measured capacitance was well-modulated in vacuum by the gate voltage due to the quantum capacitance effect. Also, the capacitance curve was shifted up to the right in the 100 ppm NO2 environment. The capacitance at zero gate bias was increased by 56.6% from the vacuum to the 100 ppm NO2 environment. These results indicate that the proposed device can be used for capacitive sensing applications.

Abstract Background In temperate regions many small mammals including bats hibernate during winter. During hibernation these small mammals occasionally wake up (arouse) to restore electrolyte and water balance. However, field data on water stress and concentration of bodily fluids during hibernation is scarce. Urinary creatinine concentration has long been used to calibrate urinary hormone concentration due to its close correlation with urine concentration. Therefore, by investigating urinary creatinine concentration, we can estimate bodily fluid concentration. In this study, we investigated changes in urinary creatinine from greater horseshoe bats (Rhinolophus ferrumequinum) hibernating in abandoned mineshafts in two regions in South Korea. Results We collected 74 urine samples from hibernating greater horseshoe bats from 2018 to 2019. We found that urinary creatinine concentration was higher in February and March and then declined in April. There were also indications of a sex difference in the pattern of change in creatinine concentration over the three months. Bats in the warmer and less humid mineshaft had higher urinary creatinine concentrations than bats in the colder and more humid mineshaft. Conclusions These results indicate that hibernating bats face water stress as urinary concentration increases during winter and that water stress may vary depending on the microenvironment. Sex differences in behaviour during hibernation may influence arousal frequency and result in sex differences in changes in urinary creatinine concentration as hibernation progresses. Although further behavioural and endocrinal investigations are needed, our study suggests that urinary creatinine concentration can be used as a proxy to estimate the hydration status of bats and the effect of sex and environmental factors on arousal patterns during hibernation.

Objective Early defibrillation is crucial for the survival of patients with out-of-hospital cardiac arrest. This study aimed to examine the trends and associated factors regarding public awareness and willingness to use automated external defibrillators (AEDs) through citywide surveys. Methods Three-round surveys were conducted in February 2012 (n=1,000), December 2016 (n=1,141), and December 2018 (n=1,001) among citizens in Daegu, South Korea, who were aged ≥19 years. The subjects were selected through a three-stage quota sampling. Awareness and willingness to use an AED were assessed in the three groups. The primary outcome was willingness to use AEDs. Results Of 3,142 respondents, 3,069 were eligible for analysis. The proportion of respondents who knew how to use AEDs increased from 4.7% in 2012 to 20.8% in 2018. Of the respondents in 2012, 2016, and 2018, 39.7%, 50.0%, and 43.2%, respectively, were willing to use an AED. Factors associated with willingness to use AEDs were male sex (adjusted odds ratio [AOR], 1.39; 95% confidence interval [CI], 1.10–1.75), cardiopulmonary resuscitation training experience in the previous 2 years (AOR, 1.80; 95% CI, 1.43–2.28), recognition of the Good Samaritan law (AOR, 1.45; 95% CI, 1.13–1.86), and awareness of how to use an AED (AOR, 4.40; 95% CI, 3.26–5.93). Conclusion To increase willingness to use AEDs, education in AED use and the Good Samaritan law, along with re-education to maintain knowledge of AED use, should be considered.

Abstract Background Systolic blood pressure (SBP) and shock index (SI) are accurate indicators of hemodynamic instability and the need for transfusion in trauma patients. We aimed to determine whether the utility and cutoff point for SBP and SI are affected by age and antihypertensives. Methods This was a retrospective observational study of a level 1 trauma center between January 2017 and December 2018. We analyzed the utility and cutoff points of SBP and SI for predicting massive transfusion (MT) and 30-day mortality according to patients’ age and whether they were taking antihypertensives. A multivariable logistic regression analysis was conducted to estimate the association of age and antihypertensives on primary and secondary outcomes. Results We analyzed 4681 trauma cases. There were 1949 patients aged 65 years or older (41.6%), and 1375 hypertensive patients (29.4%). MT was given to 137 patients (2.9%). The 30-day mortality rate was 6.3% (n = 294). In geriatric trauma patients taking antihypertensives, a prehospital SBP less than 110 mmHg was the cutoff value for predicting MT in multivariate logistic regression analyses; packed red blood cell transfusion volume decreased abruptly based on prehospital SBP of 110 mmHg. Emergency Department SI greater than 1.0 was the cutoff value for predicting MT in patients who were older than 65 years and were not taking antihypertensives. Conclusions The triage of trauma patients is based on the identification of clinical features readily identifiable by first responders. However, age and medications may also affect the accurate evaluation. In initial trauma management, we must apply SBP and SI differently depending on age, whether a patient is taking antihypertensives, and the time at which the indicators are measured.

Objective Cardiopulmonary resuscitation (CPR) education with a feedback device is known to result in better CPR skills compared to one without the feedback device. However, its long-term benefits have not been established. The purpose of this study was to evaluate the long-term CPR skill retention after training using real-time visual manikins in comparison to that of non-feedback manikins. Methods We recruited 120 general university students who were randomly divided into the real-time feedback group (RTFG) and the non-feedback group. Of them, 95 (RTFG, 48; non-feedback group, 47) attended basic life support and automated external defibrillation training for 1 hour. For comparison of retention of CPR skills, the two groups were evaluated based on 2-minute chest compression performed immediately after training and at 3, 6, and 9 months. The CPR parameters between the two groups were also compared using a generalized linear model. Results At immediately after training, the performance of RTFG was better in terms of average chest compression depth (51.9±1.1 vs. 45.5±1.1, p

Objective The incidences of prehospital advanced airway management by emergency medical technicians in South Korea are increasing; however, whether this procedure improves the survival outcomes of patients experiencing out-of-hospital cardiac arrest remains unclear. The present study aimed to investigate the association between prehospital advanced airway management and neurologic outcomes according to a transport time interval (TTI) using the Korean Cardiac Arrest Research Consortium database. Methods We retrospectively analyzed the favorable database entries that were prospectively collected between October 2015 and December 2016. Patients aged 18 years or older who experienced cardiac arrest that was presumed to be of a medical etiology and that occurred prior to the arrival of emergency medical service personnel were included. The exposure variable was the type of prehospital airway management provided by emergency medical technicians. The primary endpoint was a favorable neurologic outcome. Results Of 1,871 patients who experienced out-of-hospital cardiac arrest, 785 (42.0%), 121 (6.5%), and 965 (51.6%) were managed with bag-valve-mask ventilation, endotracheal intubation (ETI), and supraglottic airway (SGA) devices, respectively. SGAs and ETI provided no advantage in terms of favorable neurologic outcome in patients with TTIs ≥12 minutes (odds ratio [OR], 1.37; confidence interval [CI], 0.65–2.87 for SGAs; OR, 1.31; CI, 0.30–5.81 for ETI) or in patients with TTI

A graphene-based capacitive NO2 sensing device was developed by utilizing the quantum capacitance effect. We have used a graphene field-effect transistor (G-FET) device whose geometrical capacitance is enhanced by incorporating an aluminum back-gate electrode with a naturally oxidized aluminum surface as an insulating layer. When the graphene, the top-side of the device, is exposed to NO2, the quantum capacitance of graphene and, thus, the measured capacitance of the device, changed in accordance with NO2 concentrations ranging from 1–100 parts per million (ppm). The operational principle of the proposed system is also explained with the changes in gate voltage-dependent capacitance of the G-FET exposed to various concentrations of NO2. Further analyses regarding carrier density changes and potential variances under various concentrations of NO2 are also presented to strengthen the argument. The results demonstrate the feasibility of capacitive NO2 sensing using graphene and the operational principle of capacitive NO2 sensing.

(1) Background: The present study investigated the agreement between the Azure Kinect and marker-based motion analysis during functional movements. (2) Methods: Twelve healthy adults participated in this study and performed a total of six different tasks including front view squat, side view squat, forward reach, lateral reach, front view lunge, and side view lunge. Movement data were collected using an Azure Kinect and 12 infrared cameras while the participants performed the movements. The comparability between marker-based motion analysis and Azure Kinect was visualized using Bland–Altman plots and scatter plots. (3) Results: During the front view of squat motions, hip and knee joint angles showed moderate and high level of concurrent validity, respectively. The side view of squat motions showed moderate to good in the visible hip joint angles, whereas hidden hip joint angle showed poor concurrent validity. The knee joint angles showed variation between excellent and moderate concurrent validity depending on the visibility. The forward reach motions showed moderate concurrent validity for both shoulder angles, whereas the lateral reach motions showed excellent concurrent validity. During the front view of lunge motions, both the hip and knee joint angles showed moderate concurrent validity. The side view of lunge motions showed variations in concurrent validity, while the right hip joint angle showed good concurrent validity; the left hip joint showed poor concurrent validity. (4) Conclusions: The overall agreement between the Azure Kinect and marker-based motion analysis system was moderate to good when the body segments were visible to the Azure Kinect, yet the accuracy of tracking hidden body parts is still a concern.

We have determined the second mitochondrial genome of Epanerchodus koreanus Verhoeff, 1937 collected in limestone cave of Korea. The circular mitochondrial genome of E. koreanus is 15,581 bp long. It includes 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. Its gene order was different from the rest three Polydesmida mitochondrial genomes, resulted from relocation of tRNAs, rRNAs, and ND1. The base composition was AT-biased (75.1%). Phylogenetic trees displayed phylogenetic relationship, which is congruent to previous study, except Sphaerotheriidae sp. clustering with Helminthomorpha.

Background Heatstroke is one of the most serious heat-related illnesses. However, establishing public policies to prevent heatstroke remains a challenge. This study aimed to investigate the most relevant climate elements and their warning criteria to prevent outdoor heatstroke (OHS). Methods We investigated heatstroke patients from five major hospitals in Daegu metropolitan city, Korea, from June 1 to August 31, 2011 to 2016. We also collected the corresponding regional climate data from Korea Meteorological Administration. We analyzed the relationship between the climate elements and OHS occurrence by logistic regression. Results Of 70 patients who had heatstroke, 45 (64.3%) experienced it while outdoors. Considering all climate elements, only mean heat index (MHI) was related with OHS occurrence (p=0.019). Therefore, the higher the MHI, the higher the risk for OHS (adjusted odds ratio, 1.824; 95% confidence interval, 1.102–3.017). The most suitable cutoff point for MHI by Youden’s index was 30.0°C (sensitivity, 77.4%; specificity, 73.7%). Conclusion Among the climate elements, MHI was significantly associated with OHS occurrence. The optimal MHI cutoff point for OHS prevention was 30.0°C.

The Seocheon Tidal Flat is an important staging and wintering site for the Far East Russian population of Swan Goose (Anser cygnoides) in the East Asian–Australasian Flyway. However, rapid environmental changes for tourism in this area can threaten the survival of this vulnerable population by hindering sufficient rest and wintering; therefore, establishing protection strategies based on Swan Goose behavioral characteristics is necessary. Here, we estimated Swan Goose core home ranges and habitat use based on GPS tracking data collected at the Seocheon Tidal Flat in South Korea from 2017–2018. The home range of Swan Geese was estimated to be an area from Yubu Island in the south to Janggu Bay in the north; however, the core home range and habitat use characteristics differed significantly between daytime and nighttime (Day: 59.9 km2, Night: 40.3 km2, on average, 100% MCP). During the day (08:00–18:00), Swan Geese mostly spent time resting or feeding on tidal flats, especially those around tidal channels or paddy fields near Janggu Bay, whereas they mostly rested on sand dunes near Yubu Island along with the mudflats at Janggu Bay at night. Our results provide practical information on the habitat use of wintering Swan Geese population over time and indicate that Yubu Island is an important resting place. Hence, these results can contribute to evaluating threats to Swan Geese and establishing management and protection strategies for the Seocheon Tidal Flat, a major wintering site for the Far East Russian population of Swan Geese.

Obtaining Radar Cross Section (RCS) data, one of the essential parameters for aircraft design, generally takes a lot of time and cost. Measurement time and accuracy of measurement results may be affected depending on the RCS measurement method and environment. When it comes to the RCS measurement method, the direct approach, which measures RCS on a real item, is more accurate than the indirect approach, which is implemented through simulation. However, in consideration of balancing accuracy, time and cost, the indirect approach is more generally used due to its efficiency. In this paper, in order to find an optimized method for more improved prediction results of indirect approach in the high-frequency band, three prediction methods are proposed: the Prony method, the Matrix pencil method (MPM) and the Rational Function method. It is confirmed that the RCS prediction result utilizing the Prony method in the high-frequency band has the minimum error in the case of Prony and MPM Methods, which have not been utilized for RCS prediction in the high-frequency band, and the Rational function method with currently applicable cases are employed. The prediction methods are, respectively, applied to a model based on three military aircraft models such as Jet Plane, F-117 and Transport Plane, and its simulation is performed under identical conditions. The original data and the extrapolated data obtained from the methods are compared at a certain angle for each model, and the errors between the extrapolated data are also compared in order to verify the efficacy of the prediction methods.

Background. Timely treatment is important for patients with acute ischemic stroke (AIS). However, the coronavirus disease 2019 (COVID-19) outbreak may have caused delays in patient management. Therefore, we analyzed the prognosis and the time spent at the prehospital and hospital stages in managing patients diagnosed with AIS during the COVID-19 outbreak. Methods. This retrospective study evaluated patients diagnosed with AIS in the emergency department (ED) at five medical centers in Daegu city between February 18 and April 17 each year from 2018 to 2020. Data on the patients’ clinical features and time spent on management were collected and compared according to COVID-19 and pre-COVID-19 summaries. Results. From a total of 533 patients diagnosed with AIS, 399 patients visited the ED before COVID-19 and 134 during the COVID-19 outbreak. During the COVID-19 outbreak, compared with pre-COVID-19, AIS patients had poor National Institute of Health Stroke Scale scores at the initial hospital visit (6 vs. 4, p=0.013) and discharge (3 vs. 2, p=0.001). During the COVID-19 outbreak, the proportion of direct visits to hospitals through public emergency medical services (EMS) increased, and the onset of symptoms-to-ED door time via the public EMS was delayed (87 min vs. 68 min, p=0.006). Conclusions. The prognosis of AIS patients during the COVID-19 outbreak was worse than that of pre-COVID-19 patients with delays at the prehospital stage, despite the need for timely care.

OBJECTIVES Primary purpose of current research was to examine effect of goal orientation tendency on self control. METHODS Among 2018 college athlets of Korea Judo Association, participants were recruited through convinence sampling. Except for insincere replies, 215 replies were analyzed for the study. Effect of achivement goal orientation of college athletes was examined throuhgh multiple regression. path analysis with Structured equation model was applied to analyze structural relationship between achievement goal orientation and self control of college athletes, which is the main purpose of this study RESULTS At first, current research found that ego-orientation tendency and task orientation tendency have a positive effect on interpersonal relationship. Secondly, ego orientation tendency and task orientation tendency have a positive effect on psychological management of college athletes. Third, for physical management, task orientation tendency had a positive effect while it did not show significant effct on training management. Finally, as a result of analyzing structural relationship between achievement goal orientation tendency and self control, current study found that ego orientation tendency had positive effct only for interpersonal and psychological management. Task orientation tendency positively affect interpersonal, psychological, physical, and training management. CONCLUSIONS This research found significant evidence that task orientation tendency, among achievement goal orientation, positively affect self control strategy of college Judo athletes. Task orientation tendency needs to be considered to enhance athletes` performance during coaching.

Objectives Early retirement occurs when one’s job satisfaction suffers due to employment mismatch resulting from factors such as inadequate compensation. Medical doctors report high levels of job stress and burnout relative to other professionals. These levels are highest among emergency physicians (EPs), and despite general improvements in their working conditions, early retirement continues to become more common in this population. The purpose of this study was to identify the factors influencing EPs intention to retire early and to develop a probability equation for its prediction. Methods A secondary analysis of data from the 2015 Korean Society of Emergency Physicians Survey was performed. The variables potentially influencing early retirement were organized into personal characteristics, extrinsic factors, and intrinsic factors. Logistic regression analysis was performed to identify risk factors and to develop a probability equation; these findings were then arranged in a nomogram. Results Of the 377 survey respondents included in the analysis, 48.0% intended to retire early. Risk factors for early retirement included level of satisfaction with the specialty and its outlook, slanderous reviews, emergency room safety, health status, workload intensity, age, and hospital type. Intrinsic factors (i.e., slanderous reviews and satisfaction with the specialty and its outlook) had a stronger influence on early retirement than did extrinsic factors. Conclusions To promote career longevity among EPs, it is vital to improve emergency room safety and workload intensity, to enhance medical professionalism through a stronger vision of emergency medicine, and to strengthen the patient-doctor relationship.

Stroke is a major cause of disability and an evident rehabilitation strategy is crucial. Mirror therapy (MT) is one of the popular rehabilitation methods that is known to be effective as the patients benefit from the mirror illusion. However, the patient’s attention to the mirror illusion during treatment is unclear. Therefore, the present study assesses the duration and frequency of the mirror gaze, distraction, and preparation of sixteen stroke patients during two MT methods using a behavioral coding software. During the 30 min treatment, the total mirror gaze duration during conventional bilateral MT (BMT) was 564.04 s, while it was 1482.45 s in unilateral MT using a screen (UMT). The total distracted time was 945.61 s in BMT, while it was only 162.03 s in UMT. The total preparatory duration was 290.35 s in BMT and 155.53 s in UMT. The total number of distracted bouts were 136.45 in BMT, while it was 73.38 in UMT. The total number of preparatory bouts were 18.42 in BMT and 9.56 in UMT. The average times of gaze duration per bout were 5.52 s in BMT and 21.81 s in UMT. The average times of distraction per bout were 9.22 s in BMT and 3.00 s in UMT. The total number of mirror gaze bouts and average time of preparation per bout did not present a statistical significance in the comparisons of the two methods. This study assesses two methods of MT using observational coding software to evaluate the duration and frequency of the mirror gaze during treatment. The results suggest that UMT may be an alternative option to provide MT for stroke patients to increase their attention towards the mirror.

Descending necrotizing mediastinitis (DNM) is a rare form of mediastinal infection. Most cases are associated with esophageal rupture. DNM after a trigger point injection in the upper trapezius has not been described previously. We present a case of DNM after a trigger point injection in the upper trapezius. A 70-year-old man visited the emergency department with chest discomfort and fever after a trigger point injection in the left upper trapezius. Chest computed tomography showed evidence of DNM, and antibiotic therapy was immediately administered intravenously. Because of the risk of sudden death, poor prognosis due to underlying disease, and his age, he declined surgical treatment and died of septic shock. Although trigger point injections are generally considered safe, caution should be used in patients with an underlying disease or in the elderly. Early diagnosis, broad-spectrum antibiotics, and aggressive surgical management are essential to improve the prognosis.

Objective Bystander cardiopulmonary resuscitation (CPR) is an important factor associated with improved survival rates and neurologic prognoses in cases of out-of-hospital cardiac arrest. We assessed how factors related to CPR education including timing of education, period from the most recent education session, and content, affected CPR willingness. Methods In February 2012, trained interviewers conducted an interview survey of 1,000 Daegu citizens through an organized questionnaire. The subjects were aged ≥19 years and were selected by quota sampling. Their social and demographic characteristics, as well as CPR and factors related to CPR education, were investigated. Chi-square tests and multivariate logistic regression analyses were used to evaluate how education-related factors affected the willingness to perform CPR. Results Of total 1,000 cases, 48.0% were male. The multivariate analyses revealed several factors significantly associated with CPR willingness: didactic plus practice group (adjusted odds ratio [AOR], 3.38; 95% confidence interval [CI], 2.3 to 5.0), group with more than four CPR education session (AOR, 7.68; 95% CI, 3.21 to 18.35), interval of less than 6 months from the last CPR education (AOR, 4.47; 95% CI 1.29 to 15.52), and education with automated external defibrillator (AOR, 5.98; 95% CI 2.30 to 15.53). Conclusion The following were associated with increased willingness to perform CPR: practice sessions and automated electrical defibrillator training in public CPR education, more frequent CPR training, and shorter time period from the most recent CPR education sessions.

Improving outcomes after out-of-hospital cardiac arrests (OHCAs) requires an integrated approach by strengthening the chain of survival and emergency care systems. This study aimed to identify the change in outcomes over a decade and effect of citywide intervention on good neurologic outcomes after OHCAs in Daegu. This is a before- and after-intervention study to examine the association between the citywide intervention to improve the chain of survival and outcomes after OHCA. The primary outcome was a good neurologic outcome, defined as a cerebral performance category score of 1 or 2. After dividing into 3 phases according to the citywide intervention, the trends in outcomes after OHCA by primary electrocardiogram rhythm were assessed. Logistic regression analysis was used to analyze the association between the phases and outcomes. Overall, 6203 patients with OHCA were eligible. For 10 years (2008-2017), the rate of survival to discharge and the good neurologic outcomes increased from 2.6% to 8.7% and from 1.5% to 6.6%, respectively. Especially for patients with an initial shockable rhythm, these changes in outcomes were more pronounced (survival to discharge: 23.3% in 2008 to 55.0% in 2017, good neurologic outcomes: 13.3% to 46.0%). Compared with phase 1, the adjusted odds ratio (AOR) and 95% confidence intervals (CI) for good neurologic outcomes was 1.20 (95% CI: 0.78-1.85) for phase 2 and 1.64 (1.09-2.46) for phase 3. For patients with an initial shockable rhythm, the AOR for good neurologic outcomes was 3.76 (1.88-7.52) for phase 2 and 5.51 (2.77-10.98) for phase 3. Citywide improvement was observed in the good neurologic outcomes after OHCAs of medical origin, and the citywide intervention was significantly associated with better outcomes, particularly in those with initial shockable rhythm.

Chronic inflammatory skin diseases, such as atopic dermatitis, are caused by the accumulation of immune cells and the overproduction of chemokines, including CCL17 and CCL22, due to the activation of pro-inflammatory cytokines secreted from keratinocytes. In the present study, the inhibitory activity of HM-V on tumor necrosis factor alpha (TNF-α)/interferon gamma (IFN-γ)-induced pro-inflammatory cytokines was examined in human keratinocytes (HaCaTs) and 2,4-dinitrofluorobenzene (DNCB)-induced chronic skin contact dermatitis animal models. Traditional Asian medicinal herb extracts mixture (HM-V), which have been extensively used in Asian medicine, were utilized. In TNF-α/IFN-γ-induced HaCaTs, HM-V strongly inhibited mRNA and protein expression of CCL17 and CCL22 in a concentration-dependent manner. The expression of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 was also inhibited. Therefore, localized administration of HM-V in the DNCB-induced animal model alleviated immune cell deposition and skin inflammation. The results indicate that HM-V exerts inhibitory effects on keratinocyte production of CCL17 and CCL22. Furthermore, HM-V may be a useful anti-inflammatory agent for the prevention and treatment of inflammatory skin diseases.

Background and Objectives: Frontline medical staff usually experience high levels of stress, which could greatly impact their work output. We conducted a survey to investigate the level of stress and its association with job types, work departments, and medical centers among COVID-19 pandemic frontline medical personnel. Materials and Methods: We conducted a cross-sectional survey using a self-administered questionnaire among 307 frontline medical staff who cared for COVID-19 patients in Daegu city. We used a 33-item questionnaire to assess respondents’ general characteristics, job stress, personal effects associated with the COVID-19 pandemic, and their stress level. A general health questionnaire-12 (GHQ-12) was included in our questionnaire. Results: Majority (74.3%) of the respondents were in the stress group. The mean GHQ-12 score was 14.31 ± 4.96. More females (67.4%, p < 0.05) and nurses (73.3%, p = 0.001) were in the stress group compared to males and doctors. Medical staff in the general ward considered the severity of the COVID-19 pandemic situation higher. Nurses perceived work changes (p < 0.05), work burden (p < 0.05), and personal impact (p < 0.05) more serious than doctors. Medical staff in Level 3 emergency department (ED) perceived a lack of real-time information (p = 0.012), a lack of resources, and negative personal impacts associated with the pandemic as more serious than staff in Level 1 and Level 2 EDs. Medical staff in the intensive care unit perceived work changes (p < 0.05), work burden (p < 0.05), and lack of personal protective equipment (p = 0.002) as more serious than staff in the ED and general ward. Conclusion: Providing real-time information and resources for reducing work burden and negative personal impact is central to maximizing the work output of the COVID-19 pandemic frontline medical staff. Supporting their mental health through regular programs and intervention is also imperative.

Jade, a popular gemstone symbolizing beauty, grace, and longevity, is known to improve blood circulation; however, scientific research evidence is still lacking. The effect of black jade extract on the expression levels of apoptotic and osteogenic genes was validated using qPCR and flow cytometry. In combination with the use of a fluorescence microscope, osteogenic differentiation and the stained osteocytes count were analyzed. Under the pressure of benzo(a)pyrene, dermal cell apoptosis was accelerated and the osteogenic differentiation of adipose-derived stem cells (ASCs) was suppressed; but black jade extract counteracted the effects. Through an anti-apoptotic mechanism, the extract suppressed the expression of apoptotic proteins Bax and cytochrome C to 9 and 4.8 times, respectively, compared to that in dermal cells exposed to benzo(a)pyrene. During osteogenic differentiation of ASCs, the extract enhanced their differentiation despite being exposed to benzo(a)pyrene, and the relative levels of the osteoblast differentiation markers osteoponin, osteocalcin, and sclerostin were 1.87, 2.54, and 3.9 times higher, respectively, than those in the conditioned medium by benzo(a)pyrene. These effects of the extract indicate that black jade extract is very useful when applied as a functional biomaterial.

ObjectiveThis study aimed to show the epidemiological characteristics and the difference in the risk factors and types of collision between older and younger drivers in Korea.MethodsWe collected data from the Emergency Department-based Injury In-depth Surveillance retrieved by the Korea Centers for Disease Control and Prevention from 2011 to 2015. We included injured drivers aged ≥ 18 years who were registered in the database, who were limited to drivers of four-wheeled vehicles. The enrolled patients were divided according to age into older (≥ 65 years) and younger (< 65 years) drivers. The total number of enrolled drivers was 37,511; 2,361 (6.3%) of them were older drivers. The epidemiological characteristics (e.g., age, sex, fatality rate) of traffic collision victims for 5 years were determined, and the risk factors (e.g., seat belt use) and types of collision (single- vs. multi-vehicle) between the two groups were compared.ResultsThe median age and interquartile range (IQR; 25th and 75th percentiles) of all drivers were 41.0 (IQR, 32.0-52.0), and 24,544 (65.4%) of them were men. The median age increased from 40.0 (IQR, 31.0-50.0) to 43.0 (IQR, 33.0-54.0) between 2010 and 2015 (P < 0.001). The proportion of older drivers increased from 5.0% to 8.4% annually during the study period (P < 0.001). Between 2010 and 2015, the fatality rate decreased from 3.1% to 1.2% (P = 0.287) for older drivers and from 0.9% to 0.5% (P = 0.009) for younger drivers. The proportion of single-vehicle collision (25.9% vs. 20.3%) was higher in older than in younger drivers (P < 0.001). Older drivers had a lower rate of seat-belt use than younger drivers (79.0% vs. 83.0%, P < 0.001).ConclusionsThe proportion of older drivers increased annually during the study period, and older drivers experienced more single-vehicle collision and used seat belt less frequently than younger drivers. A national policy support to reduce traffic collision in older drivers and public relation activities to enhance their seat belt use should be strengthened in the future.

BackgroundNationwide and regional interventions can help improve bystander cardiopulmonary resuscitation (CPR) awareness, knowledge, and the willingness. Periodic community investigation will help monitor the effect. This study aimed to compare the experience of CPR education, CPR knowledge, and CPR willingness, during a 5-year interval.MethodsThis is a pre and post study. Two surveys were done in February 2012 and December 2016. National and regional intervention including legislation promoting public involvement, standardizing CPR education programs, training CPR instructors, and installing supporting organizations were done at the period. In both surveys, respondents were selected via quota sampling in Daegu Metropolitan City and answered the survey through face-to-face interview. Respondents' general demographic characteristics, CPR educational experience, CPR knowledge and CPR willingness were questioned.ResultsTotal of 2141 respondents (1000 in 2012, 1141 in 2016) were selected. The percentage of respondents who received CPR education itself and recent education were higher after intervention compared to before intervention (36.2% vs. 55.1%, 16.9% vs. 30.1%, respectively). Correct knowledge of performing CPR seems to be improved overall (1.6% vs. 11.7%, odd ratio 14.28, 95% confidence interval 5.68-35.94). However, less respondents were willing to perform CPR on strangers (54.5% vs 35.0%).ConclusionNationwide and regional interventions to promote bystander CPR and CPR education were associated with increased CPR education experience and improved correct CPR knowledge in performing bystander CPR. Willingness to perform bystander CPR on family did not increase significantly and CPR willingness to strangers was decreased. Additional legal and technological measures should be implemented to promote bystander CPR.

Objective This study investigated the preventable death rate in Daegu, South Korea, and assessed affecting factors and preventable factors in order to improve the treatment of regional trauma patients. Methods All traumatic deaths between January 2012 and December 2012 in 5 hospitals in Daegu were analyzed by panel review, which were classified into preventable and non-preventable deaths. We determined the factors affecting trauma deaths and the preventable factors during trauma care. Results There were overall 358 traumatic deaths during the study period. Two hundred thirty four patients were selected for the final analysis after excluding cases of death on arrival, delayed death, and unknown causes. The number of preventable death was 59 (25.2%), which was significantly associated with mode of arrival, presence of head injury, date, and time of injury. A multivariate analysis revealed that preventable death was more likely when patients were secondly transferred from another hospital, visited hospital during non-office hour, and did not have head injuries. The panel discovered 145 preventable factors, which showed that majority of factors occurred in emergency departments (49.0%), and were related with system process (76.6%). Conclusion The preventable trauma death rate in Daegu was high, and mostly process-related.

Magnetic sensors have great potential for biomedical applications, particularly, detection of magnetically-labeled biomolecules and cells. On the basis of the advantage of the planar Hall effect sensor, which consists of improved thermal stability as compared with other magnetic sensors, we have designed a portable biosensor platform that can detect magnetic labels without applying any external magnetic field. The trilayer sensor, with a composition of Ta (5 nm)/NiFe (10 nm)/Cu (x = 0 nm~1.2 nm)/IrMn (10 nm)/Ta (5 nm), was deposited on a silicon wafer using photolithography and a sputtering system, where the optimized sensor sensitivity was 6 μV/(Oe∙mA). The detection of the magnetic label was done by comparing the signals obtained in first harmonic AC mode (1f mode) using an external magnetic field and in the second harmonic AC mode (2f mode) with a self-field generated by current passing through the sensor. In addition, a technique for the β-amyloid biomarker-based antibody-antigen sandwich model was demonstrated for the detection of a series of concentrations of magnetic labels using the self-field mode method, where the signal-to-noise ratio (SNR) was high. The generated self-field was enough to detect an immobilized magnetic tag without an additional external magnetic field. Hence, it could be possible to reduce the device size to use the point-of-care testing using a portable circuit system.

Tumoral calcinosis is a rare complication in uremic patients. An in-depth review of published literature suggests that most patients with uremic tumoral calcinosis do not respond to medical treatment. Here, we report the case of a patient on peritoneal dialysis who presented with infected multifocal masses on both hip joints and was successfully treated by medical intervention. The patient was diagnosed with uremic tumoral calcinosis by physical examination and radiologic imaging, and treated with low-calcium dialysis and a non-calcium phosphate binder, sevelamer, without increasing the dose of dialysis. At the 36-month follow-up, the majority of masses had disappeared and the patient was asymptomatic.

Gold nanoshells (~160 nm in diameter) were encapsulated within a shell of temperature-responsive poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-co-AA)) using a surface-bound rationally-designed free radical initiator in water for the development of a photothermally-induced drug-delivery system. The morphologies of the resultant hydrogel-coated nanoshells were analyzed by scanning electron microscopy (SEM), while the temperature-responsive behavior of the nanoparticles was characterized by dynamic light scattering (DLS). The diameter of the P(NIPAM-co-AA) encapsulated nanoshells decreased as the solution temperature was increased, indicating a collapse of the hydrogel layer with increasing temperatures. In addition, the optical properties of the composite nanoshells were studied by UV-visible spectroscopy. The surface plasmon resonance (SPR) peak of the hydrogel-coated nanoshells appeared at ~800 nm, which lies within the tissue-transparent range that is important for biomedical applications. Furthermore, the periphery of the particles was conjugated with the model protein avidin to modify the hydrogel-coated nanoshells with a fluorescent-tagged biotin, biotin-4-fluorescein (biotin-4-FITC), for colorimetric imaging/monitoring.

The Eurasian oystercatcher (Haematopus ostralegus), Near Threatened in the IUCN red list, was designated classified endangered species II by the Ministry of Environment of Korea and a Natural Monument (No. 326) by the Cultural Heritage Administration of Korea. In this study, the complete mitochondrial genome (16,798 bp) of H. ostralegus was determined for the first time, including 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and 1 non-coding region. The overall base composition was A (31.4%), C (31.3%), G (13.8%), and T (23.5%), so the percentage of A and T (54.9%) was slightly higher than that of G and C. A phylogenetic analysis using concatenated mitogenomes revealed that the family Haematopodidae has a closer relationship with the family Recurvirostridae and H. ostralegus and H. ater clustered together. The results are expected to provide useful resources for species identification and further phylogenetic studies of genus Haematopus.

The complete mitogenome sequence of Anser cygnoides was determined and compared with those previously released. The whole mitogenome was 16,740 bp, with 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 putative non-coding region (1178 bp). The overall nucleotide composition was 30.2%, 32.0%, 15.1%, and 22.7% for A, C, G, and T, respectively. Phylogenetic analyses strongly supported two clades in Anserini and demonstrated that A. cygnoides is not monophylogenetic. This division of A. cygnoides indicates that more research is necessary to clarify phylogenetic relationships for A. cygnoides and determine how they relate to morphological traits.

GaAs photoconductive semiconductor switches (PCSSs) with comb electrodes were fabricated on semi-insulating GaAs. A pulsed 1064-nm laser with a 700-ps (FWHM) pulse width and optical energy of $134 \; \mu $ J was used to trigger 2-mm-gap PCSSs with comb lengths ranging from 0 to $750 \; \mu $ m. The effect of the comb electrodes on the output characteristics was investigated by comparing the performance parameters of sample devices with different comb lengths. Devices with a longer comb exhibited higher peak output voltage and better immunity against surface flashover. A PCSS specimen with a 750- $\mu $ m comb exhibited a higher peak output voltage by 3.53 times compared to a PCSS without a comb at bias voltages lower than 1 kV. Moreover, the PCSS with the 750- $\mu $ m comb electrode successfully generated a pulse with a peak voltage of 1.34 kV, while the peak voltage generated by a PCSS without a comb was limited to 0.74 kV.

AIM: To identify the epidemiologic characteristics of sports- and recreation-related eye injuries in a large metropolitan city and investigate risk factors associated with visual impairment. METHODS: We performed a multicenter prospective observational study on patients using the regional eye injury registry data. This study included patients with sports- and recreation-related eye injury in four tertiary teaching hospitals in Daegu, Republic of Korea, from August 2016 to July 2018. The primary outcome was visual impairment at the first hospital visit. Distributions of sex, age, place, and causative materials were analyzed according to causative activities. To examine the association between causative activities and visual impairment, a Logistic regression analysis was used. RESULTS: Of the 349 sports- and recreation-related eye injuries, soccer was the most common causative activity, with 21.8% (n=76). Sports- and recreation-related eye injuries occurred mainly in teenagers, individuals in their 20s, and men. Badminton and soccer were significantly associated with visual impairment at the first hospital visit compared with combat sports [(adjusted odds ratio (AOR), 5.18; 95% confidence interval (CI), 1.67-16.09 for badminton and AOR, 3.87; 95%CI, 1.36-10.99 for soccer]. CONCLUSION: Intervention efforts such as deployment of protective eyewear in sports facilities and schools and promotion of wearing protective eyewear during these activities in teenagers and individuals in their 20s are mandatory.

Propidium monoazide (PMA) is a highly selective dye that penetrates only membrane-compromised, dead microbial cells and inhibits both DNA extraction and amplification. PMA has been widely used for discrimination between living and dead microbial cells; however, the application of PMA in phytoplankton studies has been limited. In this study, we attempted to evaluate its applicability for the discrimination of viable phytoplankton. We tested PMA on seven phytoplankton species, Microcystis aeruginosa, Anabaena sp., Aphanizomenon sp., Synechocystis sp., Cryptomonas ovata, Scenedesmus obliquus, and Nitzschia apiculata as representatives of the major phytoplankton taxa Cyanobacteria (first four species), Chlorophyta, Cryptophyta, and Bacillariophyta, respectively. Our results showed that application of PMA to phytoplankton living in freshwater has the potential to distinguish viable from dead cells as in microbial studies. Particularly, PMA differentiated viable from dead cells in cyanobacterial species rather than in other phytoplankton taxa under our experimental conditions. However, our results also showed that it may be necessary to adjust various conditions affecting PMA treatment efficiency to expand its applicability to other phytoplankton. Although all factors contributing to the effects of PMA could not be evaluated, our study showed the applicability of PMA-based molecular approaches, which can be convenient quantitative methods for distinguishing living from dead phytoplankton in freshwater ecosystems. Setting optimal treatment conditions for other phytoplankton species may increase the efficacy of PMA-based molecular approaches.

To efficiently investigate the forage preference of Svalbard reindeer (Rangifer tarandus platyrhynchus), we applied length-heterogeneity polymerase chain reaction (LH-PCR) based on length differences of internal transcribed spacer (ITS) regions of ribosomal RNA (rRNA) to fecal samples from R. tarandus platyrhynchus. A length-heterogeneity (LH) database was constructed using both collected potential food sources of Svalbard reindeer and fecal samples, followed by PCR, cloning and sequencing. In total, eighteen fecal samples were collected between 2011 and 2012 from 2 geographic regions and 15 samples were successfully amplified by PCR. The LH-PCR analysis detected abundant peaks, 18.6 peaks on an average per sample, ranging from 100 to 500 bp in size and showing distinct patterns associated with both regions and years of sample collection. Principal component analysis (PCA) resulted in clustering of 15 fecal samples into 3 groups by the year of collection and region with a statistically significant difference at 99.9% level. The first 2 principal components (PCs) explained 71.1% of the total variation among the samples. Through comparison with LH database and identification by cloning and sequencing, lichens (Stereocaulon sp. and Ochrolechia sp.) and plant species (Salix polaris and Saxifraga oppositifolia) were detected as the food sources that contributed most to the Svalbard reindeer diet. Our results suggest that the use of LH-PCR analysis would be a non-invasive and efficient monitoring tool for characterizing the foraging strategy of Svalbard reindeer. Additionally, combining sequence information would increase its resolving power in identification of foraged diet components.