The Yellow Sea, characterized as a high-productivity ecosystem, is considered to be significantly attributable to high nutrient supply via atmospheric deposition. We observed a significant decline in ...phytoplankton biomass (~30%) over the Yellow Sea during February–May 2020 (period of COVID-19 lockdown effect) compared to the same period in 2015–2019 (period of no effect of COVID-19 lockdown). Several possible factors, such as variations in irradiance, vertical mixing, and river discharges, were not major contributors. Through the analysis of transportation and the constituents of atmospheric pollutants from Northern China (main source regions) to the Yellow Sea, we suggest that the decline in phytoplankton biomass over the Yellow Sea is mainly attributed to decreased atmospheric nutrient deposition due to the COVID-19 lockdown effect, because of decreased anthropogenic emissions in Northern China. Thus, attention should be focused on the Yellow Sea ecosystem response to increasing anthropogenic activities by lifting the COVID-19 lockdown restrictions.
•Phytoplankton biomass in the Yellow Sea declined during the COVID-19 lockdown.•Changes in irradiance, vertical mixing, and river discharges were not major contributors.•Phytoplankton decline might be resulted from decreased atmospheric nutrient deposition.•It is needed to assess the Yellow Sea ecosystem response to COVID-19 lockdown release.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Chlorhexidine (CHX) is an effective antibacterial agent and is used in dental treatment in several formulations. The aim of this study was to compare the effectiveness of CHX solution and CHX gel on ...dental plaque inhibition and gingivitis relief by a randomized clinical trial. Thirty-eight participants were randomly divided into two groups: control group (0.12% CHX solution) and test group (1% CHX gel). Participants were provided with CHX products and were instructed to use each product in the morning and evening for 1 week. Clinical results were evaluated by analyzing the collected data of Turesky et al. the modified Quigley-Hein Plaque Index (TQHPI), gingival index (GI) and the BANA test. Measurements were conducted 4 weeks and 8 weeks after using chlorhexidine products. The results were analyzed using repeated measured ANOVA and paired t-test. TQHPI and GI were significantly different after treatments in both groups (p < 0.001). The GI decreased more in the test group compared to the control group 4 weeks and 8 weeks later. In both groups, the BANA score also significantly decreased (p < 0.001) after 8 weeks, though the BANA score decreased relatively more in the CHX gel group than the CHX solution group. These results suggest that 1% CHX gel is more effective in reducing gingivitis and bacteria of periodontal disease than the 0.12% CHX solution. Therefore, the 1% CHX gel is expected to be actively used for non-surgical treatment of periodontal disease patients.
We have previously demonstrated that repeated treatment with methamphetamine (MA) results in a recognition memory impairment via upregulation of protein kinase C (PKC) δ and downregulation of the ...glutathione peroxidase‐1 (GPx‐1)‐dependent antioxidant system. We also demonstrated that far‐infrared ray (FIR) attenuates acute restraint stress via induction of the GPx‐1 gene. Herein, we investigated whether exposure to FIR modulates MA‐induced recognition memory impairment in male mice, and whether cognitive potentials mediated by FIR require modulation of the PKCδ gene, extracellular signal‐regulated kinase (ERK) 1/2, and glutathione‐dependent system. Repeated treatment with MA significantly increased PKCδ expression and its phosphorylation out of PKC isoenzymes (i.e., PKCα, PKCβI, PKCβII, PKCζ, and PKCδ expression) in the prefrontal cortex of mice. Exposure to FIR significantly attenuated MA‐induced increase in phospho‐PKCδ and decrease in phospho‐ERK 1/2. In addition, FIR further facilitated the nuclear factor E2‐related factor 2 (Nrf2)‐dependent glutathione synthetic system. Moreover, L‐buthionine‐(S, R)‐sulfoximine, an inhibitor of glutathione synthesis, counteracted the FIR‐mediated phospho‐ERK 1/2 induction and memory‐enhancing activity against MA insult. More important, positive effects of FIR are comparable to those of genetic depletion of PKCδ or the antipsychotic clozapine. Our results indicate that FIR protects against MA‐induced memory impairment via activations of the Nrf2‐dependent glutathione synthetic system, and ERK 1/2 signaling by inhibition of the PKCδ gene.
Repeated MA treatment selectively enhanced PKCδ phosphorylation in the prefrontal cortex. MA treatment resulted in a compensative induction of Nrf2 dependent glutathione induction. However, MA treatment decreased the phospho‐ERK 1/2, leads to impaired recognition memory. Whereas exposure to FIR attenuated MA‐induced PKCδ phosphorylation, and facilitated Nrf2 dependent system. Exposure to FIR protects against MA‐induced memory dysfunction via activation of ERK signaling by positive modulation of PKCδ and Nrf2. FIR‐mediated activity was counteracted by a glutathione biosynthetic inhibitor, BSO, or an ERK inhibitor, U0126. Importantly, the memory enhancing effects by FIR were comparable to those by genetic depletion of PKCδ.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Low-temperature-processed perovskite solar cells (PSCs), especially those fabricated on flexible substrates, exhibit device performance that is worse than that of high-temperature-processed PSCs. One ...of the main reasons for the inferior performance of low-temperature-processed PSCs is the loss of photogenerated electrons in the electron collection layer (ECL) or related interfaces, i.e., indium tin oxide/ECL and ECL/perovskite. Here, we report that tailoring of the energy level and electron transporting ability in oxide ECLs using Zn2SnO4 nanoparticles and quantum dots notably minimizes the loss of photogenerated electrons in the low-temperature-fabricated flexible PSC. The proposed ECL with methylammonium lead halide MAPb(I0.9Br0.1)3 leads to fabrication of significantly improved flexible PSCs with steady-state power conversion efficiency of 16.0% under AM 1.5G illumination of 100 mW cm–2 intensity. These results provide an effective method for fabricating high-performance, low-temperature solution-processed flexible PSCs.
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IJS, KILJ, NUK, PNG, UL, UM
Abstract
The western Arctic Ocean (WAO) has experienced increased heat transport into the region, sea-ice reduction, and changes to the WAO nitrous oxide (N
2
O) cycles from greenhouse gases. We ...investigated WAO N
2
O dynamics through an intensive and precise N
2
O survey during the open-water season of summer 2017. The effects of physical processes (i.e., solubility and advection) were dominant in both the surface (0–50 m) and deep layers (200–2200 m) of the northern Chukchi Sea with an under-saturation of N
2
O. By contrast, both the surface layer (0–50 m) of the southern Chukchi Sea and the intermediate (50–200 m) layer of the northern Chukchi Sea were significantly influenced by biogeochemically derived N
2
O production (i.e., through nitrification), with N
2
O over-saturation. During summer 2017, the southern region acted as a source of atmospheric N
2
O (mean: + 2.3 ± 2.7 μmol N
2
O m
−2
day
−1
), whereas the northern region acted as a sink (mean − 1.3 ± 1.5 μmol N
2
O m
−2
day
−1
). If Arctic environmental changes continue to accelerate and consequently drive the productivity of the Arctic Ocean, the WAO may become a N
2
O “hot spot”, and therefore, a key region requiring continued observations to both understand N
2
O dynamics and possibly predict their future changes.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
As the western North Pacific Ocean is located downwind of the source regions for spring Asian dust, it is an ideal location for determining the response of open waters to these events. Spatial ...analysis of spring Asian dust events from source regions to the western North Pacific, using long‐term daily aerosol index data, revealed three different transport pathways supported by the westerly wind system: one passing across the northern East/Japan Sea (40°N–50°N), a second moving over the entire East/Japan Sea (35°N–55°N), and a third flowing predominantly over the Siberian continent (>50°N). Our results indicate that strong spring Asian dust events can increase ocean primary productivity by more than 70% (>2‐fold increase in chlorophyll‐a concentrations) compared to weak/nondust conditions. Therefore, attention should be paid to the recent downturn in the number of spring Asian dust events and to the response of primary production in the western North Pacific to this change.
Key Points
There were three different transport pathways for spring Asian dust events in the study area
Ocean primary productivity was significantly increased by the spring Asian dust events
There has been a recent decrease in spring Asian dust events in the western North Pacific Ocean
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Since the start of the industrial revolution, human activities have caused a
rapid increase in atmospheric carbon dioxide (CO2) concentrations, which have, in
turn, had an impact on climate leading ...to global warming and ocean
acidification. Various approaches have been proposed to reduce atmospheric
CO2. The Martin (or iron) hypothesis suggests that ocean iron
fertilization (OIF) could be an effective method for stimulating oceanic
carbon sequestration through the biological pump in iron-limited,
high-nutrient, low-chlorophyll (HNLC) regions. To test the Martin hypothesis,
13 artificial OIF (aOIF) experiments have been performed since 1990 in HNLC
regions. These aOIF field experiments have demonstrated that primary
production (PP) can be significantly enhanced by the artificial addition of iron.
However, except in the Southern Ocean (SO) European Iron Fertilization Experiment (EIFEX),
no significant change in the effectiveness of aOIF (i.e., the amount of
iron-induced carbon export flux below the winter mixed layer depth,
MLD) has been detected. These results, including possible side effects, have been debated
amongst those who support and oppose aOIF experimentation, and many questions
concerning the effectiveness of scientific aOIF, environmental side effects, and
international aOIF law frameworks remain. In the context of increasing global
and political concerns associated with climate change, it is valuable to
examine the validity and usefulness of the aOIF experiments. Furthermore, it
is logical to carry out such experiments because they allow one to study how
plankton-based ecosystems work by providing insight into mechanisms operating
in real time and under in situ conditions. To maximize the
effectiveness of aOIF experiments under international aOIF regulations in the
future, we therefore suggest a design that incorporates several components. (1) Experiments
conducted in the center of an eddy structure when grazing
pressure is low and silicate levels are high (e.g., in the SO south of the polar front during early summer). (2) Shipboard observations
extending over a minimum of ∼40 days, with multiple iron injections (at
least two or three iron infusions of ∼2000 kg with an interval of ∼10–15 days to fertilize a patch of 300 km2 and obtain a ∼2 nM
concentration). (3) Tracing of the iron-fertilized patch using both physical
(e.g., a drifting buoy) and biogeochemical (e.g., sulfur hexafluoride,
photosynthetic quantum efficiency, and partial pressure of CO2) tracers.
(4) Employment of neutrally buoyant sediment traps (NBST) and application of the
water-column-derived thorium-234 (234Th) method at two depths (i.e., just
below the in situ MLD and at the winter MLD), with autonomous profilers equipped with an underwater video profiler
(UVP) and a transmissometer. (5) Monitoring of side effects on marine/ocean
ecosystems, including production of climate-relevant gases (e.g.,
nitrous oxide, N2O; dimethyl sulfide, DMS; and halogenated volatile organic compounds, HVOCs), decline in
oxygen inventory, and development of toxic algae blooms, with
optical-sensor-equipped autonomous moored profilers and/or autonomous benthic vehicles.
Lastly, we introduce the scientific aOIF experimental design guidelines for a
future Korean Iron Fertilization Experiment in the Southern Ocean (KIFES).
Evidence indicates that stress conditions might lead to drug dependence. Recently, we have demonstrated that exposure to far infrared ray (FIR) attenuates acute restraint stress via induction of ...glutathione peroxidase-1 (GPx-1) gene. We investigated whether FIR affects methamphetamine (MA)-induced behavioral sensitization and whether FIR-mediated pharmacological activity requires interaction between dopamine receptor and GPx-1 gene. We observed that MA treatment significantly increased GPx-1 expression in the striatum of wild-type (WT) mice. Interestingly, exposure to FIR potentiated MA-induced increase in GPx-1 expression. This phenomenon was also observed in animals receiving MA with dopamine D1 receptor antagonist SCH23390. However, dopamine D2 receptor antagonist sulpiride did not affect MA-induced GPx-1 expression. FIR exposure or SCH23390, but not sulpiride, significantly attenuated MA-induced behavioral sensitization. Exposure to FIR significantly attenuated MA-induced dopamine D1 receptor expression, c-Fos induction and oxidative burdens. FIR-mediated antioxidant effects were also more pronounced in mitochondrial- than cytosolic-fraction. In addition, FIR significantly attenuated against MA-induced changes in mitochondrial superoxide dismutase and mitochondrial GPx activities, mitochondrial transmembrane potential, intramitochondrial Ca
2+
level, mitochondrial complex-I activity, and mitochondrial oxidative burdens. The attenuation by FIR was paralleled that by SCH23390. Effects of FIR or SCH23390 were more sensitive to GPx-1 KO than WT mice, while SCH23390 treatment did not exhibit any additive effects on the protective activity mediated by FIR, indicating that dopamine D1 receptor constitutes a molecular target of FIR. Our result suggests that exposure to FIR ameliorates MA-induced behavioral sensitization via possible interaction between dopamine D1 receptor and GPx-1 gene.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We report the construction and analysis of 4,836 heterozygous diploid deletion mutants covering 98.4% of the fission yeast genome providing a tool for studying eukaryotic biology. Comprehensive gene ...dispensability comparisons with budding yeast--the only other eukaryote for which a comprehensive knockout library exists--revealed that 83% of single-copy orthologs in the two yeasts had conserved dispensability. Gene dispensability differed for certain pathways between the two yeasts, including mitochondrial translation and cell cycle checkpoint control. We show that fission yeast has more essential genes than budding yeast and that essential genes are more likely than nonessential genes to be present in a single copy, to be broadly conserved and to contain introns. Growth fitness analyses determined sets of haploinsufficient and haploproficient genes for fission yeast, and comparisons with budding yeast identified specific ribosomal proteins and RNA polymerase subunits, which may act more generally to regulate eukaryotic cell growth.
Activation of NADPH oxidase (PHOX) plays a critical role in mediating dopaminergic neuroinflammation. In the present study, we investigated the role of PHOX in methamphetamine (MA)-induced neurotoxic ...and inflammatory changes in mice.
We examined changes in mitogen-activated protein kinases (MAPKs), mitochondrial function i.e., mitochondrial membrane potential, intramitochondrial Ca(2+) accumulation, mitochondrial oxidative burdens, mitochondrial superoxide dismutase expression, and mitochondrial translocation of the cleaved form of protein kinase C delta type (cleaved PKCδ), microglial activity, and pro-apoptotic changes i.e., cytosolic cytochrome c release, cleaved caspase 3, and terminal deoxynucleotidyl transferase dUDP nick-end labeling (TUNEL) positive populations after a neurotoxic dose of MA in the striatum of mice to achieve a better understanding of the effects of apocynin, a non-specific PHOX inhibitor, or genetic inhibition of p47phox (by using p47phox knockout mice or p47phox antisense oligonucleotide) against MA-induced dopaminergic neurotoxicity.
Phosphorylation of extracellular signal-regulated kinases (ERK1/2) was most pronounced out of MAPKs after MA. We observed MA-induced phosphorylation and membrane translocation of p47phox in the striatum of mice. The activation of p47phox promoted mitochondrial stresses followed by microglial activation into the M1 phenotype, and pro-apoptotic changes, and led to dopaminergic impairments. ERK activated these signaling pathways. Apocynin or genetic inhibition of p47phox significantly protected these signaling processes induced by MA. ERK inhibitor U0126 did not exhibit any additional positive effects against protective activity mediated by apocynin or p47phox genetic inhibition, suggesting that ERK regulates p47phox activation, and ERK constitutes the crucial target for apocynin-mediated inhibition of PHOX activation.
Our results indicate that the neuroprotective mechanism of apocynin against MA insult is via preventing mitochondrial burdens, microglial activation, and pro-apoptotic signaling process by the ERK-dependent activation of p47phox.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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