In an image from the Geostationary Ocean Color Imager (GOCI) taken on 13 June 2011, a recurrent floating green algae bloom was detected around Qingdao. To detect the bloom an index based on ...multi-spectral band ratios using three wavelengths (555, 660, 745nm) was utilized. One month later, the GOCI images detected widespread floating green algae patches (east–west elongated) across the Yellow Sea and East China Sea (YS, ECS). The presence of the patches was confirmed from various oceanic observation cruises.
Lagrangian particle tracking experiments were conducted to understand the pathway of the floating green algae patches and interpret the physical forcing factors that affect the distribution and advection of the floating green algae. The numerical simulation results indicated that dominant southerly winds during June and July 2011 were related to offshore movement of the floating green algae, especially their eastward extension in the YS/ECS. An infrequent and unusual event occurred in June 2011: a typhoon MEARI, caused the green algae to detach from the coast and initiated movement to the east. After the typhoon event, sea surface temperature recovered rapidly enough to grow the floating green algae, and wind and local current controlled the movement of the massive floating algae patches (coastal accumulation or offshore advection in the YS/ECS). Analysis of the floating green algae pixels' movement during passage of Typhoon MAON in July 2011 revealed that the floating green algae patches were significantly controlled by both ocean currents and enhanced winds. These findings suggest that the floating green algae bloom off Qingdao and in the middle of the YS and ECS in the summer of 2011 occurred due to the combined effects of recent rapid expansion of seaweed aquaculture, strong winds, and the wind patterns in blooming regions. Our combined approach, using satellite data and numerical simulations, provides a robust estimate for tracing and monitoring changes in green algae blooms on a regional scale.
•GOCI detected massive green algae bloom during summer 2011 across Yellow Sea.•Combined effects of surface currents and winds were responsible for the bloom.•The winds were induced by typhoons, and such a bloom was not observed previously.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Large quantities of microplastics are thought to be emitted to freshwater environments via wastewater treatment plants (WWTPs). To evaluate the occurrence of microplastics in Korean WWTPs, a ...nationwide study was conducted for the first time in 50 representative WWTPs with large treatment capacities. Grab sampling and laboratory filtration were used for influents, whereas in situ filtration using a custom-made sampling device was used for effluents. The filtrates were pretreated using wet peroxidation and density separation prior to the identification of microplastics with a dissection microscope and Fourier-transform infrared spectroscopy. Pooled analyses of the microplastics revealed that they were predominantly fragment-shaped, and thermoplastics and synthetic fibers were the dominant microplastic materials in WWTPs. The concentration ranged from 10 to 470 L–1 in influents and 0.004 to 0.51 L–1 in effluents. The removal efficiency of microplastics during wastewater treatment was calculated to be 98.7–99.99% in 31 WWTPs. Additionally, WWTPs using advanced phosphorus removal processes exhibited higher removal efficiency than those not implementing such processes. Power-law distribution was successful in describing microplastic particle sizes down to 100 μm, although it was not applicable for smaller particles. This comprehensive monitoring study provides information on the current level and characteristics of microplastics in WWTPs in Korea.
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IJS, KILJ, NUK, PNG, UL, UM
Surface seawater temperature in the southwestern coast of Korea suddenly rose in the summer of 2017. This rapid temperature rise event occurred simultaneously with a change in wind direction in the ...Korea Strait from northwesterly to southeasterly due to the approach of typhoon Noru. To identify the causes of the abrupt rise in surface temperature, the variations of the surface currents and temperature were investigated using a three-dimensional ocean circulation model. Warm and less saline surface water, a mixed shelf water of the Changjiang Diluted Water and saline water from an onshore branch of the Kuroshio in the East China Sea (ECS), flowed northeastward to the west and south of Jeju Island, proceeding eastward through the Jeju and Korea Straits. While westerly winds prevailed, wind-driven ageostrophic currents flowed southeastward, moving away from the south coast of Korea, due to Ekman transport. The shallow coastal region was occupied by cool and saline surface water (T < 22 °C, S > 32.5 psu). However, after the wind shifted to an easterly direction, the surface ageostrophic currents realigned northwestward, and the warm and less saline water moved into the shallow coastal region. In a passive tracer dispersal experiment, dyes injected from the ECS flowed to the west of Jeju Island and through the Jeju Strait via geostrophic currents. These dyes did not affect the shallow southern coastal region of Korea while the westerly winds dominated. However, during the easterly wind event, the dyes were advected toward the coast by the coastward Ekman transport. An analysis of temperature data observed at Cheongsando over 16 years and the tracer experiment revealed that the abrupt temperature rise in the summer of 2017 was a marine heatwave event generated by the advection of warm and less saline surface water from the ECS to the southwestern coast of Korea through the Jeju Strait.
•Warm and less saline surface water flows east through the Jeju Strait in summer.•This surface current is primarily in geostrophic balance.•Wind-driven ageostrophic current drifted warm surface water toward the coast.•Surface temperature increased and salinity decreased rapidly in the coastal region.•The warm and less saline water originated from the surface of the East China Sea.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Beginning in 2006, epidemics of a fatal lung injury of unknown cause in children were observed in Korea every spring. A recent study demonstrated that this type of children's interstitial lung ...disease (chILD) is associated with humidifier disinfectant use.
To determine the clinical characteristics of this type of chILD and to assess whether the nationwide suspension of humidifier disinfectant sales in the autumn of 2011 affected its incidence.
The clinical characteristics of suspected cases between 2006 and 2011 were determined by a nationwide retrospective study. The potential causal relationship with humidifier disinfectants was examined by a prospective surveillance study after humidifier disinfectant sales were suspended.
In total, 138 children were diagnosed with this type of chILD, which was characterized by rapid progression, high mortality, predominance in the spring season, and a familial tendency. The annual incidence increased in 2011 and then dropped to zero in 2012. The children were on average 30.4 months old. The most frequent symptoms at admission were cough and dyspnea. As the disease progressed, the typical complication was spontaneous air leak. Eighty children (58%) died. Two years after humidifier disinfectant-sale suspension, no more new cases were found.
This study suggests that humidifier disinfectant inhalation causes an idiopathic type of chILD that is characterized by spontaneous air leak, rapid progression, lack of response to treatment, and high mortality. Further safety studies must be performed on common environmental compounds, particularly those that enter the human body by an unusual route.
The occurrence of numerous cases of interstitial lung disease in children (chILD) every spring in Korea starting in 2006 raised suspicion about a causal relationship with the use of humidifier ...disinfectants (HDs). The aim of this study was to evaluate the association between HD use and the risk of chILD.
This retrospective, 1∶3 matched case-control study consisted of 16 cases of chILD that had developed between 2010 and 2011. The three groups of parallel controls (patients with acute lobar pneumonia, asthma, and healthy children) were matched by age, gender, and index date. Indoor/outdoor environmental risk factors, including HD use, were investigated by asking the guardians to complete a questionnaire.
The median age of the affected children (43.8% male) was 26 months (18.25-36.25). The chILD group did not differ significantly from the control groups with respect to socio-demographic and clinical variables. Indoor and outdoor environmental factors were not associated with a risk of chILD. However, the previous use of HDs (OR; 2.73. 95% CI; 1.41-5.90, P = 0.00) were independently associated with an increased risk.
This study showed that HDs, which are widely used in South Korea in the winter season, independently increased the risk of chILD in spring. Therefore, continuous monitoring and, if needed, changes in policy are essential to prevent and control pediatric diseases caused by toxic chemicals.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Characteristic Hospital-based study Population-based study Case Control Number 1239 447 3361 Responders to questionnaire, n (%) NA NA 3299 (98.2) Age (y) 5.18 ± 3.86 9.32 ± 2.47 8.75 ± 2.90 Sex (M/F) ...717/522 231/216 1719/1588 BMIlow * NA NA 17.89 ± 3.17 Lifetime AD symptoms NA NA 709 of 2349 (23.2%) Parental history of allergic diseases NA NA 1068 of 3056 (34.9%) Parental history of asthma NA NA 117 of 2911 (4.0%) Parental history of AR NA NA 953 of 3033 (31.4%) Parental history of AD NA NA 237 of 2933 (8.1%) Environmental tobacco smoking NA NA 1342 of 3095 (43.4%) Educational level of mother <=High school graduate NA NA 1242 of 3039 (40.9%) >=University graduate NA NA 1797 of 3039 (59.1%) Economic state (monthly income) Low (<3 million won) NA NA 1282 of 2977 (43.1%) Middle (3-5 million won) NA NA 1280 of 2977 (43.0%) High (>=5 million won) NA NA 415 of 2977 (13.9%) Mold exposure (visible mold) During infancy NA NA 564 of 2932 (19.2%) During the previous year NA NA 635 of 2930 (21.7%) Biomarker Total IgE (IU/mL) 512.62 ± 1095.99 57.70 ± 124.34 204.08 ± 394.16 Claudin-1 Frequency of rs9290929 A 0.933 0.953 0.946 G 0.067 0.047 0.054 Table E1 Subject characteristics Values are mean ± SD or proportion.AR, Allergic rhinitis; F, female; M, male; NA, not available. Risk factors AD Sx everlow * aOR (95% CI)dagger P value Demographic factors Sex: male 1.11 (0.91-1.34) .299 BMI 1.03 (0.99-1.06) .142 Age 0.92 (0.89-0.96) <.001 Higher economic state (monthly income >=5 million won) 1.05 (0.78-1.41) .747 Maternal education (<university graduate) 0.90 (0.73-1.12) .338 Genetic factors Parental history of allergic disease 1.70 (1.41-2.06)double dagger <.001 Parental history of AD 2.82 (2.09-3.79)double dagger <.001 Parental history of AR 1.31 (1.06-1.61) .013 Parental history of asthma 1.36 (0.87-2.13) .171 Environmental factors Environmental tobacco smoking 1.06 (0.87-1.28) .570 Pet ownership in the past 12 mo 0.89 (0.63-1.25) .490 Pet ownership during infancy 1.42 (0.94-2.14) .098 Mold exposure during infancy (visible mold) 1.60 (1.26-2.03) <.001 Biomarkers Total IgE (>200.0 IU/mL) 1.20 (0.94-1.53) .138 Table E2 Risk factors for AD in the population-based study Data were calculated by logistic regression multivariate analysis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Variations in seawater temperature have a critical influence on marine ecosystems and aquaculture industries in coastal regions. From July 25 to August 5, 2017, the sea surface temperature off the ...southwestern coast of Korea rose rapidly from 17.1 °C to 27.3 °C, which induced environmental stress in marine organisms such as farmed abalone. This study investigated the cause of this abrupt sea temperature rise. Westerly winds from July 1 to 25 were favorable for the upwelling of cold subsurface water along the bottom slope in this coastal region, helping maintain cool surface water temperatures. As the wind changed to easterly, the cold subsurface water moved away and warmer, fresher surface water moved into the coastal region, where the surface currents changed from a southeastward flow to a northeastward flow from July 25 to August 5. Thus, to maintain stable, cool seawater temperatures during summer, both cold water supply and upwelling wind conditions are essential. The analysis of water masses indicated that the cold water was formed by the mixing of the Tsushima Warm Current Water and Yellow Sea Bottom Water in the northern East China Sea. The cold water advected eastward and formed a cold water pool in the intermediate depths (30–80 m) of the northern Jeju Strait, providing cold water to the coastal region during the upwelling period. The westerly winds were disrupted by the approach of a typhoon, which discontinued the supply of bottom cold water. The physical processes identified in this study will help predict short-term increases in water temperature and can assist in the development of countermeasures for the aquaculture industry against the negative effects of abrupt environmental changes.
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•Subsurface cold water pool (CWP) advects to the northern Jeju Strait in summer.•The CWP on the northern slope of Jeju Strait upwells due to westerly winds.•Coastal upwelling of the CWP maintains surface cool water in the coastal region.•An easterly wind event causes a retreat of CWP and an abrupt rise of temperature.•The CWP forms by subsurface mixing of cold and warm water masses in the East China Sea.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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Artificial scaffolds made up of various synthetic biodegradable polymers have been reported to have many advantages including cheap manufacturing, easy scale up, high mechanical ...strength, convenient manipulation, and molding into an unlimited variety of shapes. However, the synthetic biodegradable polymers still have the insufficiency for cartilage regeneration owing to their acidic degradation products. To reduce acidification by degradation of synthetic polymers, we incorporated magnesium hydroxide (MH) nanoparticles into porous polymer scaffold not only to effectively neutralize the acidic hydrolysate but also to minimize the structural disturbance of scaffolds. The neutralization effect of poly(D,L-lactic-co-glycolic acid; PLGA)/MH scaffold was confirmed with the maintenance of neutral pH, contrary to a PLGA scaffold with low pH. Further, the scaffolds were applied to evaluate the chondrogenic differentiation of the human bone marrow mesenchymal stem cells. In in vitro study, the PLGA/MH scaffold enhanced the chondrogenesis markers and reduced the calcification, compared to the PLGA scaffold. Additionally, the PLGA/MH scaffold reduced the release of inflammatory cytokines, compared to the PLGA scaffold, as the cell death decreased. Moreover, the addition of MH reduced necrotic cell death at the early stage of chondrogenic differentiation. Further, the necrotic cell death by the PLGA scaffold was mediated by cleavage of caspase-1, the so-called interleukin 1-converting enzyme, and MH alleviated it as well as nuclear factor kappa B expression. Furthermore, the PLGA/MH scaffold highly supported chondrogenic healing of rat osteochondral defect sites in in vivo study. Therefore, it was suggested that a synthetic polymer scaffold containing MH could be a novel healing tool to support cartilage regeneration and further treatment of orthopedic patients.
Synthetic polymer scaffolds have been widely utilized for tissue regeneration. However, they have a disadvantage of releasing acidic products through degradation. This paper demonstrated a novel type of synthetic polymer scaffold with pH-neutralizing ceramic nanoparticles composed of magnesium hydroxide for cartilage regeneration. This polymer showed pH-neutralization property during polymer degradation and significant enhancement of chondrogenic differentiation of mesenchymal stem cells. It reduced not only chondrogenic calcification but also release of proinflammatory cytokines. Moreover, it has an inhibitory effect on necrotic cell death, particularly caspase-1-mediated necrotic cell death (pyroptosis). In in vivo study, it showed higher healing rate of the damaged cartilage in a rat osteochondral defect model. We expected that this novel type of scaffold can be effectively applied to support cartilage regeneration and further treatment of orthopedic patients.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Diffuse alveolar hemorrhage (DAH) is a life-threatening pulmonary complication in patients with hematologic malignancies or autoimmune disorders, and it has a high mortality rate. The current ...treatment options of corticosteroids, transfusions, and immunosuppressants have been limited and largely unsuccessful, and they can be accompanied by multiple complications. Intrapulmonary administration of recombinant activated factor VII (rFVIIa) has been reported in adults, but there are scarce data on its use in children. The present article reviews our institutional experience with intrapulmonary rFVIIa for the treatment of DAH in children. The study included 6 pediatric patients with acute, bronchoscopically confirmed DAH treated between 2011 and 2013. The median age was 11 years, and patient diagnoses were as follows: acute myeloid leukemia (2 patients), myelodysplastic syndrome (1 patient), hemophagocytic lymphohistiocytosis (1 patient), T-cell lymphoblastic lymphoma (1 patient), and idiopathic pulmonary hemosiderosis (1 patient). These patients were treated with intrapulmonary rFVIIa concurrent with methylprednisolone, fresh-frozen plasma, and maintenance of the platelet count >50 000/mm(3). Complete and sustained hemostasis after rFVIIa treatment and an absence of adverse events were observed in all patients. The PaO2/fraction of inspired oxygen ratio increased significantly, and rapid clinical improvements were observed. Two patients who received hematopoietic stem cell transplantation died of subsequent respiratory syncytial virus and Acinetobacter baumannii infections, but the other 4 patients exhibited rapid improvement, were successfully weaned from ventilators, and experienced long-term survival. Our findings indicate that intrapulmonary administration of rFVIIa is an effective and safe treatment option for children with DAH; however, further clinical studies are needed.
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