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We obtained a detailed bathymetry dataset using multi-beam echo sounder around Neunggeol located at Southern part in Ulleungdo. The survey period was from September 1, 2019 and the bathymetry survey was carried out by RV Jangmok No2 of Korea Institute of Ocean Science and Technology. The instrument equipment used for the survey were Kongsbergs’s EM2040 (multi-beam echo sounder). The detailed bathymetry of the study area shows gradually depth change from about 4 to 190 m. The study area has relatively gentle slopes from the coast to 25 m and below about 125 m in depth, but a steep slope from about 25 to 125 m. The rocky bottom zones identified from detailed bathymetry and backscattered seafloor images are distributed in the northeastern sea of the coastal area, the central sea, and around Neunggeol. In particular, Neunggeol and the near large outcropping rock are tumulus-like submarine landforms, forming big vertical walls. The submarine cable buried between Ulleungdo and the Korean mainland appears in the northern seafloor of the survey area. Stopper stones and gravels sediment are distributed around it. The rocky bottom zone has a strong and irregular reflection intensity in the seafloor backscattered image and the sandy sediment zone has a relatively weak reflection intensity and a uniform pattern, so the two zones are well divided. We classified the sediment zones into fine-grained sediments, sandy sediments, and gravel-like sediments by using the different reflection intensities due to differences in sediment particle size in the seafloor image. Detailed bathymetry and seafloor backscattered image dataset around Neunggeol can be used as a basic data for habitat environment mapping.

Dokdo Island’s diverse marine ecosystem requires long-term monitoring to understand the effects of rapid environmental changes, such as global warming, on macrobenthos species and communities. Current studies are often short-term and limited, highlighting the need for extended research to predict future changes to ecosystems. This study analyzed the environmental variables influencing macrobenthos through long-term monitoring. In total, 511 species (spp./23.4 m2) were identified with an abundance of 1709.9 individuals/m2 and a diversity of 2.9. Since 2020, there has been a decline in both the number of species and diversity, attributed to changes in sediment composition, particularly an increase in gravel and sand. The dominant species include the crustacean Abludomelita denticulata (17.6%), the polychaete Haplosyllis spongiphila (6.8%), the bivalve Glycymeris munda (5.6%), the polychaete Opisthodonta uraga (5.3%), and the bivalve Limatula japonica (3.8%). The macrobenthos community differs each year, as the dominant species G. munda has decreased in abundance since 2022 and L. japonica since 2021. Depth and gravel sediment strongly correlated with community variation. Site-specific analysis also showed significant differences, with depth, bottom temperature, and sediment composition as the influencing factors. These species thrive in cold water but their abundance declines with an increase in temperature. Continuous long-term monitoring is essential to understand and protect the Dokdo ecosystem amid rapid environmental changes. Long-term monitoring studies have revealed more species than have short-term studies, showing annual and site-specific environmental changes, including sediment erosion and bottom temperature increases. These changes have affected macrobenthos diversity, abundance, and community composition, necessitating ongoing research to determine the persistence of these trends and to protect the ecosystem.

Background. Lumbar spinal stenosis (LSS) causes low back pain, leg pain, numbness in the leg, and neurogenic intermittent claudication. Epidural steroid injection (ESI) has been used for treating spinal stenosis symptoms. We hypothesized that dural pulsation was variable for lumbar spinal stenosis. In cases of the presence of dural pulsation, the pain relief after the ESI was better than in the absence of dural pulsation. This study aimed at investigating the relationships between the presence or absence of spinal dural pulsations and the efficacy of ESI. Methods. A total of 71 patients were enrolled in this prospective study. Prior to the ESI, the dural pulsation was measured using a 5-1 MHz array ultrasound transducer. The visual analogue scale (VAS) score was measured pre-ESI and 2 weeks post-ESI and 4 weeks post-ESI. At 4 weeks post-ESI, dural pulsation was rechecked. Results. The VAS scores improved after the ESI procedure regardless of the presence or absence of dural pulsation. There was a correlation between the pulsation of the dura and post-ESI VAS scores. However, VAS was not significantly different for different grades of stenosis. Conclusion. The ESI was effective in patients with spinal stenosis in short-term follow-up. Dural pulsation of the spinal cord was a positive predictive factor for the ESI effect, but the grade of spinal stenosis severity had no effect on the effectiveness of ESI.

We obtained a dataset through beach and submarine topography surveys around Hujeoung coast in Uljin. We conducted the beach and submarine topography surveys using small vessels from July 8 to July 11, 2016. The surveying instruments used for the surveys were Shipborne Mobile LiDAR System and Multi-beam Echo Sounder (Kongsberg EM3001). The beach topography was observed up to about 6 m from the shoreline. The width of the beach is about 30 m to 40 m. In the southeast of the survey area, there is an exposed rock with a depth of about 20 m. The area around the rock has sandy sediments. Datasets of the Hujeong coast area can be used for continuous monitoring to development of coastal erosion control system.

We obtained detailed bathymetry and seafloor image datasets using multi-beam echo sounder and side scan sonar around Seonam at Ilsan beach in Ulsan. The survey was conducted from May 9 to May 12, 2018, using a small vessel. The equipment used for the survey was R2Sonic's Sonic 2020 (Multi-beam Echo Sounder) and EdgeTech’s 4125 (Side Scan Sonar). The detailed bathymetry of the study area shows slightly different topographical features for each part around Seonam. The eastern and southern parts have steep slopes and the depth of the water in the areas deepens away from the surroundings of the submerged bedrock area adjacent to Seonam. The water depth in the western and northern part is shallower with a relatively gentle slope, compared to the eastern and southern parts. The rocky bottom zones are mainly distributed in the eastern part area with the water depth range of 3 to 9 m around the Seonam. Some rocky areas also appear in the western region. Seafloor backscatter image shows irregular, complex reflection patterns of acoustic intensity mainly in the eastern and western adjacent areas around Seonam, and in the northern and southern coastal waters, which are almost identical to the underwater rock zones with shallow water depth. The detailed bathymetry and seafloor image datasets around Seonam, using the multi-beam echo sounder and the side scan sonar, can be used as an essential data for environment habitat mapping.

Abstract Submarine earthquakes have increased in the southwestern Ulleung Basin adjacent to the Korean Peninsula. This study analyzed the gravitational and magnetic properties of the three earthquake-prone areas (Hupo Bank and offshore regions near Pohang and Ulsan) in the basin. The basin was affected by tensile and compressive stresses during the formation of the East Sea. The southern Hupo Bank and the Pohang offshore exhibited high gravity anomalies and strong magnetic anomalies. Hupo Bank was separated from the peninsula and earthquakes in this region have been influenced by crustal fractures that facilitated igneous activities during the formation of the basin. Dense volcanic rocks and seaward dipping reflectors along the Pohang coast and continental slope suggest magmatic activities during the formation of the East Sea. Comparatively, the Ulsan offshore, with a thick sedimentary layer, exhibited a slightly higher gravity anomaly than the surrounding area, but no significant differences in the magnetic anomaly. Sequential tensile and compressive stresses related to the creation of the basin produced complex tectonic structures in this region. The magnetic tilt derivative results suggest that earthquakes were located near magnetic source boundaries. The results show that it is important to monitor earthquake-prone areas with gravity and magnetic anomalies.

The purpose of this report was to present successful cases and technical notes of the patients with up migrated cervical disc herniation to the upper level who were successfully treated using anterior cervical discectomy and fusion (ACDF), describing the evaluation of treatment outcomes and perioperative complications. The cases of two patients who had ACDF in symptomatic up migrated cervical disc herniation to the upper level in February 2021 and November 2021 were reviewed. Two patients presented with a six-week history of posterior neck pain and radiating pain. Preoperative magnetic resonance imaging (MRI) confirmed a diagnosis of up migrated cervical disc extrusion. The patients were admitted to Daegu Wooridul Spine Hospital in Daegu, Korea. ACDF was performed under general anesthesia. Treatment outcomes were examined by comparing pre and postoperative Numeric Rating Scale (NRS), and MRI. Treatment outcomes were favorable: posterior neck pain and radiating pain showed a significant reduction in NRS. Postoperative MRI showed that the up migrated discs were successfully removed in both cases. Neither patient developed perioperative complications. Anterior cervical discectomy can be feasible in patients with symptomatic up migrated cervical disc herniation to the upper level.

This report was aimed to share our successful cases of only surgical decompression for multilevel lumbar spinal stenosis, by assessing treatment outcomes. Two patients who had only surgical decompression for multilevel lumbar spinal stenosis were investigated. They were diagnosed with the calcified disc protrusion and vacuum disc in the intervertebral space by magnetic resonance imaging (MRI) and computed tomography (CT). The chief complaints were severe low back pain and bilateral sciatica 2 or 3 months ago. The patients also reported difficulty walking due to sciatica. Unilateral laminotomy for bilateral decompression was performed and discectomy was not done on the stenosis levels. Treatment outcomes were analyzed by visual analog scale for low back pain and sciatica (Back VAS, Leg VAS), improvement in walking, and postoperative MRI. Treatment outcomes were favorable: Low back pain and bilateral sciatica showed a VAS score improvement (Back VAS =3, Leg VAS=3), the patient’s walking was improved, and on a postoperative MRI of the two patients, the thecal sac was released sufficiently. The patients developed no perioperative complications. Only surgical decompression is an effective method for multilevel lumbar spinal stenosis with calcified disc protrusion and vacuum disc in the intervertebral space.

Dokdo, a volcanic island located in offshore waters, is significantly influenced by various currents and the island effect resulting from upwelling events. Despite these factors, there is a limited understanding of the seasonal changes in phytoplankton populations and their relationship with the environmental factors in the waters around Dokdo, even during dramatic shifts in phytoplankton dynamics. We focused on seasonal oceanographic features over three years (2018, 2019, and 2020) to understand the phytoplankton community structure and seasonal species succession. Winter, characterized by thorough mixing, results in high nutrient levels, leading to increased phytoplankton biomass. The dominance of the large-sized diatom Chaetoceros spp. contributes to relatively low diversity (H’: 1.14 ± 0.31). In contrast to the typical coastal waters, spring exhibits dominance by the small nano-flagellates and Cryptomonas spp. associated with a lack of surface nutrients due to increased water temperature. Summer, characterized by strong stratification, shows low phytoplankton biomass but high Chl. a concentrations, possibly influenced by picoplankton and the emergence of dinoflagellates, such as Gyrodinium sp. and Katodinium sp., which increases diversity (H’: 2.18 ± 0.28). In autumn, there is typically a phytoplankton bloom, but in 2019, an unusually low biomass occurred. This was likely due to the intrusion of deep, cold water from the bottom and low-salinity Changjiang diluted water (CDW) from the surface, increasing the water’s stability. This, in turn, led to nutrient depletion, contributing to a rise in diversity (H’: 1.14 ± 0.31). These environmentally complex waters around Dokdo result in a distinct pattern of biodiversity indices, with the highest in summer and the lowest in winter, differing from typical temperate waters. In conclusion, this research highlights the substantial influence of distinctive oceanographic features and nutrient dynamics on the phytoplankton biomass and biodiversity in the Ulleung Basin and Dokdo region. Understanding these patterns is vital for the effective management of marine ecosystems and fisheries resources, emphasizing the necessity for continued long-term monitoring in the vicinity of the Dokdo area.

Background: Low back pain (LBP) is caused by disc herniation, spinal stenosis, facet syndrome or etc. This LBP could be either nociceptive or neuropathic pain (NP). In addition, these neuropathic pain is a major contributor to chronic low back pain. It is already known that lumbar epidural steroid injection (ESI) is effective for low back pain, but no study has assessed both nociceptive and neuropathic pain separately. This study investigated whether neuropathic or nociceptive pain was better improved after an epidural steroid injection. Methods: This was a prospective study. Patients were classified according to the pre-procedure painDETECT questionnaire (PD-Q) score. If the PD-Q score was ≤12, it was considered as nociceptive pain, and it the PD-Q was ≥19, it was considered NP. The patients were given a transforaminal (TF) or interlaminar (IL) epidural steroid injection (ESI). The PD-Q was filled out by each patient prior to the ESI (baseline), and again at 4 weeks after the ESI. Outcomes was assessed using a numerical rating scale (NRS) score, short form McGill Pain Questionnaire (MPQ), and revised Oswestry Back Disability Index (ODI) at 1 month later. Results: A total of 114 patients were enrolled and of these, 54 patients with a PD-Q score of ≤12 were classified into the nociceptive pain, and 60 patients with a PD-Q score ≥19 were classified into the neuropathic pain group. At 1 month after treatment, both groups had significantly lower than improved their mean NRS score. Not withstanding these improvements and difference between NRS, the differences in MPQ and ODI after treatment between the groups (nociceptive vs. neuropathic) not significant. After the procedure (TF-ESI or IL-ESI), the patients in group 1 (PD-Q score ≤12, n = 54) had no change in their PD-Q score. Among the patients in group 2 (pre-treatment PD-Q score ≥19, n = 41), 13 patients moved to a PD-Q score

Nine sesquiterpenes, including eight pentalenenes (1–8) and one bolinane derivative (9), were isolated from the culture broth of a marine-derived actinobacterium Streptomyces qinglanensis 213DD-006. Among them, 1, 4, 7, and 9 were new compounds. Their planar structures were determined by spectroscopic methods (HRMS, 1D, and 2D NMR), and the absolute configuration was established by biosynthesis consideration and electronic-circular-dichroism (ECD) calculations. All the isolated compounds were screened for their cytotoxicity against six solid and seven blood cancer cell lines. Compounds 4–6 and 8 showed a moderate activity against all of the tested solid cell lines, with GI50 values ranging from 1.97 to 3.46 µM.

Cement-augmented pedicle screw instrumentation (CAPSI) is a widely used surgical technique in posterior spondylodesis of osteoporotic patients. Complications related to cement leakage after CAPSI was rarely reported compare to that of vertebroplasty, kyphoplasty and most of them are asymptomatic. Herein the authors report the case of a 67-year-old female who experienced cardiac perforation by string shape cement embolus after CAPSI. She underwent the foreign body removal operation through the 5th intercostal thoracotomy and she was well recovered consequently. Surgeons should be aware of this complication entity when encounter postoperative chest pain to avoid fatal results. The authors also reviewed the case reports for cardiac perforation by cement embolus and preventive modalities for the cement leakage.

The CHEMTAX program has been widely used to estimate community composition based on major pigment concentrations in seawater. However, because CHEMTAX is an underdetermined optimization algorithm, underdetermined bias has remained an unsolved problem since its development in 1996. The risk of producing biased results increases when analyzing the picophytoplankton community; therefore, this study tested a new method for avoiding biased CHEMTAX results using the picophytoplankton community around the East Sea (Japan Sea). This method involves building a linear model between pigment concentration data and community composition data based on DNA sequencing to predict the pigment range for each operational taxonomic unit, based on the 95% prediction interval. Finally, the range data are transformed into an initial ratio and ratio limits for CHEMTAX analysis. Three combinations of initial ratios and ratio limits were tested to determine whether the modeled initial ratio and ratio limit could prevent underdetermined bias in the CHEMTAX estimates; these combinations were the modeled initial ratio and ratio limit, the modeled initial ratio with a default ratio limit of 500 s, and an initial ratio from previous research with the default ratio limit. The final ratio and composition data for each combination were compared with Bayesian compositional estimator-based final ratio and composition data, which are robust against underdetermined bias. Only CHEMTAX analysis using the modeled initial ratio and ratio limit was unbiased; all other combinations showed significant signs of bias. Therefore, the findings in this study indicate that ratio limits and the initial ratio are equally important in the CHEMTAX analysis of biased datasets. Moreover, we obtained statistically supported initial ratios and ratio limits through linear modeling of pigment concentrations and 16s rDNA composition data.

We measured oxygen (O2) fluxes in two major shallow subtidal benthic habitats (kelp bed (KB) and bare rock (BR) covered with crustose coralline algae) of Dokdo islet in the East Sea by applying noninvasive in-situ aquatic eddy covariance (AEC). The AEC device allows time series measurements (~24 h) of three-dimensional velocity (u, v, and w components) and high-resolution dissolved O2. This allows estimation of O2 exchange flux via benthic habitats. Local flow rates and irradiance levels were found to be major factors controlling O2 exchange flux in the rocky habitats. Gross primary production rates tended to be significantly higher in KB (163 mmol O2 m−2 d−1) than in BR (51 mmol O2 m−2 d−1). The net ecosystem metabolisms were assessed as opposite types, with 8 mmol O2 m−2 d−1 in KB (autotrophy) and –12 mmol O2 m−2 d−1 in BR (heterotrophy). Our results indicate that kelp beds are important for organic carbon cycling in rocky coastal waters and that AEC application to macroalgae habitats is a useful assessment approach.

We characterized the biogeochemical organic carbon (Corg) cycles in the surface sediment layer of the Ulleung Basin (UB) of the East Sea. The total oxygen uptake (TOU) rate and the diffusive oxygen uptake (DOU) rate of the sediment were measured using an autonomous in situ benthic lander equipped with a benthic chamber (KIOST BelcII) and a microprofiler (KIOST BelpII). The TOU rate was in the range of 1.51 to 1.93 mmol O2 m−2 d−1, about double the DOU rate. The high TOU/DOU ratio implies that the benthic biological activity in the upper sediment layer is one of the important factors controlling benthic remineralization. The in situ oxygen exposure time was about 20 days, which is comparable to the values of other continental margin sediments. The sedimentary Corg oxidation rates ranged from 6.4 to 6.5 g C m−2 yr−1, which accounted for ~2% of the primary production in UB. The Corg burial fluxes ranged from 3.14 ± 0.12 to 3.48 ± 0.60 g C m−2 yr−1, corresponding to more than 30% of the deposited Corg buried into the inactive sediment deep layer.

Circular to subcircular boreholes were found on the surfaces of three different bivalve shells (Mactra chinensis, Felaniella usta, and Nuttallia japonica) that were pushed onto the sand beach at Sagot Cape, Baengnyeongdo, Korea. The boreholes are characterized by beveled holes that are parabolic in cross section. The boreholes are classified into the ichnospecies Oichnus paraboloides, probably drilled by a naticid gastropod Glossaulax didyma didyma living in the Baengnyeong tidal flat. In the case of Mactrashells, boreholes are observed more or less evenly on left and right valves, and 96% of boreholes are located on the umbo. This may suggest that the life position of the Baengnyeong bivalves did not dictate the preference of G. didyma didyma in the Baengnyeong tidal flat ecosystem. The clustered distribution of the boreholes in the umbo area indicates a strong site selectivity for boreholes that is quite a common phenomenon in many naticid gastropods. Keywords: Baengnyeongdo, Mactra chinensis, Naticid gastropods, Oichnus paraboloides, Preyâpredator interactions

ObjectiveThis study aimed to assess the effect of combined oral contraceptives (COCs) on polycystic ovarian morphology (PCOM) and serum anti-Müllerian hormone (AMH) levels in Korean women with polycystic ovary syndrome (PCOS).MethodsThis university hospital study enrolled 36 Korean women who were newly diagnosed with PCOS based on the Rotterdam criteria and were treated with COCs for at least 1 year. We retrospectively evaluated the ovarian volume and number of antral follicles using ultrasonography and assessed serum AMH levels at baseline and after 1 year of COC treatment.ResultsSignificant decreases in ovarian volume and antral follicle count were observed after 1 year of COC treatment. Compared to baseline, serum AMH levels were significantly decreased after 1 year.ConclusionCOC treatment significantly affects ultrasound-assessed PCOM and serum AMH levels of patients with PCOS.

Objective We evaluated the efficacy of diffusion-weighted magnetic resonance imaging (DW-MRI) in detecting perioperative cerebral thromboembolic events after anterior cervical discectomy and fusion (ACDF). Methods This retrospective case series included 51 consecutive patients that underwent ACDF. To assess baseline presence of plaque or stenosis, all patients were assessed for risk factors of cerebrovascular events and underwent carotid ultrasound preoperatively and cerebral DW-MRI was performed in all patients postoperatively, with areas of high signal intensity interpreted as a cerebral thromboembolic event. Results One male patient who underwent a C4/5 ACDF had a focal diffusion abnormality on DW-MRI concerning for cerebral thromboembolic events in the right posterior cerebral artery territory. He remained asymptomatic and did not display related neurological symptoms, such as visual deficits. Conclusion Asymptomatic cerebral thromboembolic events can be detected by DW-MRI after ACDF. The incidence of such events remains very rare despite the direct manipulation and associated alteration of common carotid artery flow dynamics.

BackgroundMethadone is a synthetic opioid that is widely used for the treatment of chronic pain. The association between methadone treatment and QT interval prolongation or which can lead to torsades de pointes has been confirmed with larger studies on high dose methadone. The aim of this study was to determine the effect of methadone on the QTc interval in patients, whether the daily dose of methadone should be lower than what has been previously investigated.MethodsA total of 130 patients were included, with 90 patients in the methadone group and 40 patients in the control group. For each ECG, heart rate, QT interval and corrected QT (QTc) interval were recorded. The patient demographics, methadone dose and serum level, duration of methadone use and past medical history were collected.ResultsThe QTc interval was significantly longer in the treatment group than in the control group (443 ± 30.0 ms versus 408 ± 28.0 ms, respectively, P < 0.0001) and more patients in the treatment group had a QTc interval greater than 450 ms (36.7% versus 7.5%, respectively, P = 0.0005). The QTc interval was not associated with methadone dose P = 0.9278), serum level (P = 0.2256) or duration of treatment (P = 0.1822).ConclusionsThis study has shown that methadone use is associated with longer QTc intervals, even among patients with daily doses of less than 80 mg. In this study, no correlation was found between QTc duration and methadone dose, serum levels or duration of use. However, the magnitude of the QTc interval was associated with female gender and the use of antidepressants.