The Interplay of Mycosporine-like Amino Acids between Phytoplankton Groups and Northern Krill (Thysanoessa sp.) in a High-Latitude Fjord (Kongsfjorden, Svalbard).

We investigated pigment and mycosporine-like amino acid (MAA) concentrations of phytoplankton and Northern krill (Thysanoessa sp.) in sub-Arctic Kongsfjorden. Chlorophyll a (Chl-a) concentrations in the surface and middle-layer water were 0.44 µg L-1 (±0.17 µg L-1) and 0.63 µg L-1 (±0.25 µg L-1), respectively. Alloxanthin (Allo, a marker of cryptophytes) was observed at all stations, and its mean values for surface and middle-layer water were 0.09 µg L-1 (±0.05 µg L-1) and 0.05 (±0.02 µg L-1), respectively. The mean MAA-to-Chl-a ratios at the surface (3.31 ± 2.58 µg (µg Chl-a)-1) were significantly higher than those in the middle-layer water (0.88 ± 0.49 µg (µg Chl-a)-1), suggesting that these compounds play an important role in reducing UV photodamage. In gut pigment levels of Northern krill, the most abundant accessory pigment was Allo (2.79 ± 0.33 µg g-1 dry weight; d.w.), as was the accumulation of Chl-a (8.29 ± 1.13 µg g-1 d.w.). The average concentration of MAAs was 1.87 mg g-1 d.w. (±0.88 mg g-1 d.w.) in krill eyes, which was higher than that in all other body parts (0.99 ± 0.41 mg g-1 d.w.), except for the gut. Thysanoessa sp. was found to contain five identified MAAs (shinorine, palythine, porphyra-334, mycosporine-glycine, and M-332) in the krill eye, whereas shinorine and porphyra-334 were only observed in the krill body, not the eyes and gut. These findings suggest that Northern krill accumulate MAAs of various compositions through the diet (mainly cryptophytes) and translocate them among their body parts as an adaptation for photoprotection and physiological demands.

Islandinium minutum subsp. barbatum subsp. nov. (Dinoflagellata), a New Organic-Walled Dinoflagellate Cyst from the Western Arctic: Morphology, Phylogenetic Position Based on SSU rDNA and LSU rDNA, and Distribution.

A study of modern sediment from the Western Arctic has revealed the presence of a distinctive brown-colored cyst with a spherical central body bearing unbranched processes that are usually solid with a small basal pericoel. Distinctive barbs project from some processes, and process tips are usually minutely expanded into conjoined barbs. The archeopyle is apical and saphopylic. This cyst corresponds to Islandinium? cezare morphotype 2 of Head et al. (2001, J. Quat. Sci., 16:621). Phylogenetic analyses based on the small and large subunit rRNA genes infer close relationship with Islandinium minutum, the type of which is that of the genus. Re-examination of specimens of I. minutum reveals the presence of minute barbs on its processes, but differences with Islandinium? cezare morphotype 2 remain based on size, process distribution, and barb development. Furthermore, the internal transcribed spacer shows I. minutum to be distinct from this morphotype. On the basis of these small but discrete differences, we propose the new subspecies Islandinium minutum subsp. barbatum subsp. nov. Molecular sequencing of other cysts encountered, namely Echinidinium karaense, an unidentified flattened cyst, and "Polykrikos quadratus", places them in the Monovela clade, the latter showing greater morphological variability than previously thought.

Aerosolized Fibrin Sealant Is Effective for Postoperative Edema and Ecchymosis in Open Rhinoplasty Without Osteotomy.

PURPOSE: Fibrin sealant (FS) was approved as a hemostatic agent, sealant, and adhesive by the Food and Drug Administration in 1998. Our study sought to determine whether FS also reduced edema and pain in rhinoplasty without osteotomy. MATERIALS AND METHODS: We conducted a prospective randomized trial involving patients who underwent open rhinoplasty without osteotomy. The patients were randomly assigned to 1 of 2 groups: those treated with aerosolized FS (FS group) and those not treated (control group). The effect of FS on edema of the eyelid, edema of the dorsum and tip of the nose, and periorbital ecchymosis was separately rated postoperatively using a scale of 0 to 4 or 0 to 3. Postoperative pain was evaluated using questionnaires quantified with a visual analog scale. The Mann-Whitney U and Wilcoxon tests were used to compare parameters between the groups. RESULTS: A total of 41 patients were included in this study. The FS group (n = 20) consisted of 13 male and 7 female patients with a mean age of 34.8 ± 5.8 years. The control group (n = 21) consisted of 15 male and 6 female patients with a mean age of 32.4 ± 4.8 years. There were no statistically significant differences between the 2 groups with respect to age, gender, or combined surgical techniques (P > .05). Aerosolized FS significantly reduced not only ecchymosis and swelling in the periorbital area but also edema of the nasal dorsum (P < .05). CONCLUSIONS: Aerosolized FS can be effective for reducing eyelid edema, dorsal edema, and periorbital ecchymosis after open rhinoplasty. FS may serve as an adhesive for minimizing dead space by promoting adherence of the skin flap and as a hemostatic agent in reducing the amount of postoperative bleeding by sealing capillary vessels.

Low-concentration hypochlorous acid nasal irrigation for chronic sinonasal symptoms: a prospective randomized placebo-controlled study.

Low-concentration hypochlorous acid (HOCl) is an endogenous antibacterial and antiviral agent. The purpose of this study was to evaluate the effectiveness of HOCl irrigation in patients with chronic rhinosinusitis (CRS) refractory to medical therapy. Forty-three adult patients (mean age 45.5 years) were enrolled in this study. They were randomly chosen to receive nasal irrigation with either low-concentration HOCl generated by a Salicid device (n = 21), or a placebo (saline; n = 22) for 8 weeks. The outcome measures were scores on the 20-Item SinoNasal Outcome Test (SNOT-20), rhinosinusitis disability index (RSDI), nasal endoscopic score, and bacterial cultures. The SNOT-20 scores were significantly lower in the HOCl group than in the placebo group after 2 weeks of treatment (p < 0.05) and remained lower after 4 weeks of treatment. With respect to the RSDI scores, there was a significant improvement in the HOCl group at 1 week after treatment and in both groups at 2 weeks after treatment (p < 0.05). There were no significant differences in the endoscopic scores between the two groups after the treatment. The bacterial culture rates were lower in the HOCl group than in the placebo group after 4 weeks of treatment, but this was not significant (p > 0.05). Our results showed that low-concentration HOCl irrigation resulted in a greater improvement in CRS symptoms as compared to saline irrigation.

Enzymatic modification by point mutation and functional analysis of an omega-6 fatty acid desaturase from Arctic Chlamydomonas sp.

Arctic Chlamydomonas sp. is a dominant microalgal strain in cold or frozen freshwater in the Arctic region. The full-length open reading frame of the omega-6 fatty acid desaturase gene (AChFAD6) was obtained from the transcriptomic database of Arctic Chlamydomonas sp. from the KOPRI culture collection of polar micro-organisms. Amino acid sequence analysis indicated the presence of three conserved histidine-rich segments as unique characteristics of omega-6 fatty acid desaturases, and three transmembrane regions transported to plastidic membranes by chloroplast transit peptides in the N-terminal region. The AChFAD6 desaturase activity was examined by expressing wild-type and V254A mutant (Mut-AChFAD6) heterologous recombinant proteins. Quantitative gas chromatography indicated that the concentration of linoleic acids in AChFAD6-transformed cells increased more than 3-fold [6.73 ± 0.13 mg g-1 dry cell weight (DCW)] compared with cells transformed with vector alone. In contrast, transformation with Mut-AChFAD6 increased the concentration of oleic acid to 9.23 ± 0.18 mg g-1 DCW, indicating a change in enzymatic activity to mimic that of stearoyl-CoA desaturase. These results demonstrate that AChFAD6 of Arctic Chlamydomonas sp. increases membrane fluidity by enhancing denaturation of C18 fatty acids and facilitates production of large quantities of linoleic fatty acids in prokaryotic expression systems.

Comparative analysis of the expression of E-cadherin, ß-catenin, and ß1 integrin in congenital and acquired cholesteatoma.

E-cadherin, ß-catenin, and ß1 integrin are important cell adhesion molecules to maintain epithelial structure and function. We investigated the expression of these cell adhesion molecules in cholesteatomas to understand the role of cell-cell and cell-extracellular matrix interaction in cholesteatomas. An immunohistochemical investigation was carried out on 35 cholesteatoma tissue samples (14 congenital, 21 acquired cholesteatomas) and 10 normal retroauricular skin (RAS) tissues which are obtained during middle ear surgery. The expression rate was measured to find out differences between retroauricular skin and cholesteatoma, as well as between congenital and acquired cholesteatoma. E-cadherin expression rate was significantly lower in the cholesteatoma (spinous layer 88.7 ± 17.9 %, granular layer 54.6 ± 22.6 %) than in the RAS (100 %, 74.4 ± 7.4 %) and in the acquired (83.3 ± 19.4 %, 48.1 ± 22.9 %) than in the congenital (96.7 ± 12.0 %, 64.4 ± 18.8 %). ß-catenin expression rate was significantly lower in the cholesteatoma (spinous layer 84.1 ± 17.2 %, granular layer 28.7 ± 30.8 %) than in the RAS (100 %, 75.9 ± 6.1 %) and in the acquired (78.1 ± 17.0 %, 17.1 ± 22.3 %) than in the congenital (93.2 ± 13.5 %, 46.1 ± 34.2 %). The expression pattern of ß-catenin is similar to that of E-cadherin. In ß1 integrin, there was no significant difference of the expression rate between RAS and cholesteatoma, as well as between congenital and acquired cholesteatoma. In conclusion, the expression of E-cadherin and ß-catenin is reduced in cholesteatoma, and the reduction is more pronounced in acquired cholesteatoma than in congenital cholesteatoma. Acquired cholesteatomas showed more aggressive characteristics than congenital cholesteatomas in terms of cell-cell adhesion.

The Total Synthesis of Inostamycin†A.

The first total synthesis of inostamycin A is described. With efficient and stereoselective synthetic routes to aldehyde 3 and ketone 4 developed through asymmetric aldol reactions, addition reactions and reduction, and with chiral building blocks, the two large fragments were coupled with remarkable anti stereoselectivity and efficiency by aldol condensation. The coupling reaction provided the complete carbon skeleton with all the requisite functional groups and stereogenic centers for inostamycin A. The two quaternary carbons at C20 and C16 of ketone 4 were elaborated in a highly stereocontrolled manner by addition reactions of the transmetallated 5 to ethyl ketone 6 and the transmetallated 7 to methyl ketone 8, respectively, in which the use of LaCl3 for transmetallation was critical for high coupling efficiency.

Aureimonas glaciistagni sp. nov., isolated from a melt pond on Arctic sea ice.

A Gram-staining-negative, motile, aerobic and rod-shaped bacterial strain, PAMC 27157T, was isolated from a melt pond on sea ice in the Chukchi Sea. Phylogenetic analysis of the 16S rRNA gene sequence of strain PAMC 27157T revealed an affiliation to the genus Aureimonas with the closest sequence similarity (96.2 %) to that of Aureimonas phyllosphaerae. Strain PAMC 27157T grew optimally at 30 °C and pH 7.0 in the presence of 3.5 % (w/v) NaCl. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylmonomethylethanolamine, sulfoquinovosyldiacylglycerol and an unidentified aminolipid. The major cellular fatty acid was summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c, 83.1 %) and the major respiratory quinone was Q-10. The genomic DNA G+C content was 69.1 mol%. The combined phylogenetic, phenotypic and chemotaxonomic data showed that strain PAMC 27157T could be clearly distinguished from species of the genus Aureimonas with validly published names. Thus, strain PAMC 27157T should be classified as representing a novel species in the genus Aureimonas, for which the name Aureimonas glaciistagni sp. nov. is proposed. The type strain is PAMC 27157T ( = KCCM 43049T = JCM 30183T).

Investigation of the interaction between a novel unnatural chiral ligand and reactant on palladium for asymmetric hydrogenation.

We report about the mechanistic studies of the reaction between a newly synthesized (S)-2-((R)-3H-dinaphtho[2,1-c:1',2'-e]azepin-4(5H)-yl)-2-phenylethanol based on the binaphthyl skeleton and (E)-2-methyl-5-phenylpent-2-enoic acid for the asymmetric hydrogenation of α,ß-unsaturated acids with heterogeneous palladium catalysts. The specific interactions between the chiral ligand and reactant were investigated in solution with palladium nanoparticles, as well as under ultrahigh vacuum (UHV) conditions on the palladium metal surface in the absence of hydrogen. The reactions were explored using nuclear magnetic resonance (NMR) spectroscopy, scanning tunneling microscopy (STM), and high-resolution photoemission spectroscopy (HRPES) combined with density functional theory (DFT) calculations. A NMR study identified the interaction between both molecules with palladium nanoparticles in solution. In addition, STM and HRPES studies revealed the spatial distribution and configuration of both compounds on the palladium metal surface under UHV conditions. The theoretical results support the experimental results with respect to the interaction energy value. It was found that the reaction between the ligand and reactant occurs with hydrogen bonding on palladium surface, simultaneously. The present study provides mechanistic details of the asymmetric hydrogenation reaction, which bears a correlation between the ligand, reactant, and catalyst during the reaction.

Production rate estimation of mycosporine-like amino acids in two Arctic melt ponds by stable isotope probing with NAH(13) CO3.

The net carbon uptake rate and net production rate of mycosporine-like amino acids (MAAs) were measured in phytoplankton from 2 different melt ponds (MPs; closed and open type pond) in the western Arctic Ocean using a (13) C stable isotope tracer technique. The Research Vessel Araon visited ice-covered western-central basins situated at 82°N and 173°E in the summer of 2012, when Arctic sea ice declined to a record minimum. The average net carbon uptake rate of the phytoplankton in polycarbonate (PC) bottles in the closed MP was 3.24 mg C · m(-3) · h(-1) (SD = ±1.12 mg C · m(-3) · h(-1) ), while that in the open MP was 1.3 mg C · m(-3) · h(-1) (SD = ±0.05 mg C · m(-3) · h(-1) ). The net production rate of total MAAs in incubated PC bottles was highest (1.44 (SD = ±0.24) ng C · L(-1) · h(-1) ) in the open MP and lowest (0.05 (SD = ±0.003) ng C · L(-1) · h(-1) ) in the closed MP. The net production rate of shinorine and palythine in incubated PC bottles at the open MP presented significantly high values 0.76 (SD = ±0.12) ng C · L(-1) · h(-1) and 0.53 (SD = ±0.06) ng C · L(-1) · h(-1) . Our results showed that high net production rate of MAAs in the open MP was enhanced by a combination of osmotic and UVR stress and that in situ net production rates of individual MAA can be determined using (13) C tracer in MPs in Arctic sea ice.

Insight into the latitudinal gradient of biodiversity based on spatial variations in pelagic ciliate communities along the western Arctic Ocean.

The latitudinal dynamics of biodiversity has been the focus of global attention. This study is based on the latitude gradient of biodiversity in the spatial changes of pelagic ciliate communities in the western Arctic Ocean. The gradient pattern of pelagic ciliate communities across four latitudes were investigated from the water surface at 22 sampling station in the northern Bering Sea of the western Arctic Ocean and Chukchi Sea from August 5 to August 24, 2016. Based on multivariate analyses, the results showed that (1) the spatial patterns of pelagic ciliates represented a significant latitudinal gradient along the western Arctic Ocean; (2) the species number and abundance of pelagic ciliate communities declined from 64°N to 80°N; (3) variations in the horizontal distribution of ciliates were significantly correlated with changes in physicochemical variables, especially water temperature and Chl a; Thus it is suggested that the expected latitudinal decline of biodiversity was evident along the western Arctic Ocean.

Enhancing Surface Modification and Carrier Extraction in Inverted Perovskite Solar Cells via Self-Assembled Monolayers.

Perovskite solar cells (PSCs) have been significantly improved by utilizing an inorganic hole-transporting layer (HTL), such as nickel oxide. Despite the promising properties, there are still limitations due to defects. Recently, research on self-assembled monolayers (SAMs) is being actively conducted, which shows promise in reducing defects and enhancing device performance. In this study, we successfully engineered a p-i-n perovskite solar cell structure utilizing HC-A1 and HC-A4 molecules. These SAM molecules were found to enhance the grain morphology and uniformity of the perovskite film, which are critical factors in determining optical properties and device performance. Notably, HC-A4 demonstrated superior performance due to its distinct hydrophilic properties with a contact angle of 50.3°, attributable to its unique functional groups. Overall, the HC-A4-applied film exhibited efficient carrier extraction properties, attaining a carrier lifetime of 117.33 ns. Furthermore, HC-A4 contributed to superior device performance, achieving the highest device efficiency of 20% and demonstrating outstanding thermal stability over 300 h.

Expression of dehydrin gene from Arctic Cerastium arcticum increases abiotic stress tolerance and enhances the fermentation capacity of a genetically engineered Saccharomyces cerevisiae laboratory strain.

We investigated Arctic plants to determine if they have a specific mechanism enabling them to adapt to extreme environments because they are subject to such conditions throughout their life cycles. Among the cell defense systems of the Arctic mouse-ear chickweed Cerastium arcticum, we identified a stress-responsive dehydrin gene CaDHN that belongs to the SK5 subclass and contains conserved regions with one S segment at the N-terminus and five K segments from the N-terminus to the C-terminus. To investigate the molecular properties of CaDHN, the yeast Saccharomyces was transformed with CaDHN. CaDHN-expressing transgenic yeast (TG) cells recovered more rapidly from challenge with exogenous stimuli, including oxidants (hydrogen peroxide, menadione, and tert-butyl hydroperoxide), high salinity, freezing and thawing, and metal (Zn(2+)), than wild-type (WT) cells. TG cells were sensitive to copper, cobalt, and sodium dodecyl sulfate. In addition, the cell survival of TG cells was higher than that of WT cells when cells at the mid-log and stationary stages were exposed to increased ethanol concentrations. There was a significant difference in cultures that have an ethanol content >16 %. During glucose-based batch fermentation at generally used (30 °C) and low (18 °C) temperatures, TG cells produced a higher alcohol concentration through improved cell survival. Specifically, the final alcohol concentrations were 13.3 and 13.2 % in TG cells during fermentation at 30 and 18 °C, respectively, whereas they were 10.2 and 9.4 %, respectively, in WT cells under the same fermentation conditions. An in vitro assay revealed that purified CaDHN acted as a reactive oxygen species scavenger by neutralizing H2O2 and a chaperone by preventing high temperature-mediated catalase inactivation. Taken together, our results show that CaDHN expression in transgenic yeast confers tolerance to various abiotic stresses by improving redox homeostasis and enhances fermentation capacity, especially at low temperatures (18 °C).

Treatment of obstructive sleep apnea syndrome using radiofrequency-assisted uvulopalatoplasty with tonsillectomy.

Radiofrequency surgery was introduced to minimize thermal damage to the tissue. A radiofrequency electrode can be used to make cuts in the free edge of the soft palate like those done in laser-assisted uvulopalatoplasty [radiofrequency-assisted uvulopalatoplasty (RAUP)]. Tonsillectomy can enlarge the lateral diameter of the pharynx. The aim of our study was to evaluate the efficacy of RAUP with tonsillectomy in treatment of obstructive sleep apnea syndrome (OSAS). Ninety-two patients with obstructive sleep apnea were included in this study. Patients were categorized according to disease severity and Friedman's staging system. Patients were assessed with the preoperative visual analog scale (VAS) for snoring, Epworth Sleepiness Scale (ESS) and apnea-hypopnea index (AHI) at baseline and repeated at 6 months postoperatively. The intensity of postoperative pain, speech deficits and dysphagia were also recorded. There was a significant improvement in the VAS score for snoring, ESS and AHI before and after surgery. Overall, the results of the present study indicated a surgery success rate (a 50 % decrease in AHI and AHI <20) of 66 % (61 of 92 patients). Postoperative pain, speech deficits and dysphagia were reduced at 2 weeks after surgery. The results of this study suggest that RAUP with tonsillectomy is an effective treatment for patients with OSAS.

Synergistic Effect of Size-Tailored Structural Engineering and Postinterface Modification for Highly Efficient and Stable Dye-Sensitized Solar Cells.

Despite significant progress in device performance, dye-sensitized solar cells (DSSCs) continue to fall short of their theoretical potential. Moreover, research in recent years needs to pay more attention to improving the device fabrication process. To achieve the theoretical efficiency limit, it is crucial to optimize the interface between the dye and TiO2 nanoparticles in the entire device stack. Our study indicates that optimizing the structure or size of the coadsorbents and implementing a monolayer adsorption process can be an effective strategy to reduce charge recombination and enhance light-harvesting properties. Our research aims to develop a surface-coating adsorbent plan that controls the TiO2 nanoparticle interface to achieve the radiative limit of power conversion efficiency (PCE). Specifically, we utilized 2-thiophenecarboxylic acid (THCA) or chenodeoxycholic acid (CDCA) as postinterfacial surface-coating adsorbents. Our results demonstrate that this approach effectively achieves the desired PCE limit. Combined with the coadsorbent structure engineering and interface optimization, the device increased the packing area on the TiO2 nanoparticles' surface, reaching an improved PCE of over 13.17% under simulated sunlight (1.5G), which is the highest efficiency of a porphyrin single dye-based DSSC. In particular, this practical approach was also applied to a large-area DSSC with an area of 3 cm2, yielding a remarkable PCE of 9.04%. Furthermore, when applied to a polymer gel electrolyte, this novel approach recorded the highest PCE of 11.16% with a long-term operational stability of up to 1000 h for the quasi-solid-state DSSCs. Our research findings provide a promising avenue for achieving high-performance DSSCs with ease of access and demonstrate practical applications as alternatives to conventional power sources.

Atlantic-origin water extension into the Pacific Arctic induced an anomalous biogeochemical event.

The Arctic Ocean is facing dramatic environmental and ecosystem changes. In this context, an international multiship survey project was undertaken in 2020 to obtain current baseline data. During the survey, unusually low dissolved oxygen and acidified water were found in a high-seas fishable area of the western (Pacific-side) Arctic Ocean. Herein, we show that the Beaufort Gyre shrinks to the east of an ocean ridge and forms a front between the water within the gyre and the water from the eastern (Atlantic-side) Arctic. That phenomenon triggers a frontal northward flow along the ocean ridge. This flow likely transports the low oxygen and acidified water toward the high-seas fishable area; similar biogeochemical properties had previously been observed only on the shelf-slope north of the East Siberian Sea.

Draft genome sequence of Moritella dasanensis strain ArB 0140, a psychrophilic bacterium isolated from the Arctic Ocean.

The psychrophilic bacterium Moritella dasanensis strain ArB 0140 was isolated near a glacier in Kongsfjorden, Svalbard Archipelago, Norway. Here we report a 4.89-Mb draft genome sequence of Moritella dasanensis ArB 0140, which could provide comprehensive information on a psychrophilic mechanism in extreme environments.

Characterization of the ice-binding protein from Arctic yeast Leucosporidium sp. AY30.

Previously, we reported the ice-binding protein (LeIBP) from the Arctic yeast Leucosporidium sp. AY30. In this study we provide physicochemical characterization of this IBP, which belongs to a class of IBPs that exhibited no significant similarity in primary structure to other known antifreeze proteins (AFPs). We compared native, glycosylated and non-glycosylated recombinant LeIBPs. Interestingly, size-exclusion chromatography and analytical ultracentrifugation revealed that LeIBP self-associates with a reversible dimer with K(d) values in the range 3.45-7.24×10(-6) M. Circular dichroism (CD) spectra showed that LeIBP, glycosylated or non-glycosylated, is predominantly composed of ß-strand secondary structural elements (54.6%), similar to other ß-helical antifreeze proteins (AFPs). In thermal hysteresis (TH) activity measurements, native LeIBP was twice more active (0.87 °C at 15 mg/mL) than that of the recombinant IBPs (0.43-0.42 °C at 10.8 mg/mL). This discrepancy is probably due to uncharacterized enhancing factors carried over during ice affinity purification, because glycosylated and non-glycosylated recombinant proteins displayed similarly low activity. Ice recrystallization inhibition (RI) activities of the native and recombinant LeIBPs were comparable. Measurements of CD, TH activity, and RI showed that glycosylation does not cause structural changes and is not required for function. An ice-etching experiment using green fluorescent protein-tagged IBP revealed that LeIBP binds, just as hyperactive AFPs, to both basal and pyramidal prism planes of the ice crystal. Taken together, our results indicate that LeIBP, structurally similar to hyperactive AFPs, is moderately active and that a reversible dimer has no effect on its activity.

The Effect of Gate Work Function and Electrode Gap on Wide Band-Gap Sn-Doped α-Ga2O3 Metal-Semiconductor Field-Effect Transistors.

We present technology computer aided design (TCAD) results for wide band-gap Sn-doped α-Ga2O3 metal-semiconductor field-effect transistors (MESFETs). In particular, the effect of gate work function and electrode gap length on the electrical characteristics is demonstrated for a thorough understanding of the behavior of such devices. The gate work function significantly affects the reverse bias drain current under the gate-current dominant regime, whereas a gate-source/drain gap larger than 0.1 µm has a negligible effect on the drain current.

Factors affecting the subsurface aragonite undersaturation layer in the Pacific Arctic region.

This study evaluated interannual variation in the subsurface aragonite undersaturation zone (ΩAr<1 layer) in the Pacific Arctic Ocean, using data from the 2016-2019 period. The upper boundary (DEPΩ<1UB) of the ΩAr<1 layer generally formed at a depth where the contribution of corrosive Pacific water was approximately 98 %. The intensity of the Beaufort Gyre associated with freshwater accumulation mainly determined interannual variation in DEPΩ<1UB, but the direction of its effect was opposite west and east of ~166°W. The lower boundary (DEPΩ<1LB) of the ΩAr<1 layer was generally found at a depth range where equal contributions of Pacific and Atlantic water were expected. An Atlantic-origin cold saline water intrusion event in 2017 caused by an anomalous atmospheric circulation pattern significantly lifted the DEPΩ<1LB, thus the thickness of the ΩAr<1 layer decreased.