89 research outputs found
Molecular Characterization of Thyroid Hormone Receptors (TRs) and their Responsiveness to T3 in Microhyla fissipes
To explore and enrich the molecular mechanisms of thyroid hormone receptors (TRs) in the metamorphosis of amphibians, the cDNA sequences of TR alpha and TR beta in Microhyla fissipes were cloned and characterized. TR alpha was 1 706 bp in length with an open reading frame (ORF) of 1 257 bp encoding a predicted protein of 418 amino acids and TR beta was 1 422 bp with an ORF of 1 122 bp encoding a predicted protein of 373 amino acids. Their protein sequences contained 4 conserved domains of the nuclear receptor superfamily with two highly conserved cysteine-rich zinc fingers in the DNA-binding domain, whereas TR beta was 42 amino acids shorter in its A/B domain than TR alpha. Highly-conserved sequences and structures indicated their conserved functions during metamorphosis. TR alpha expression reached peak at 12 h and then decreased from 12 h to 48 h. While dramatically up-regulated TR beta was observed after exposure of T3 within 24 h, and it was down-regulated from 24 h to 48 h. The expression pattern of TR beta is similar to that in the natural metamorphosis. Furthermore, tadpoles treated 24 h also resembled the climax of metamorphosis tadpoles and TR beta expression had higher responsiveness than TR alpha to T3 in M. fissipes. These results suggest M. fissipes may serve as the model to assay environmental compounds on TH signaling disruption
N-[(S)-1-(3,5-Dimethyl-2-hydroxyÂphenyl)Âethyl]-N-[(R)-2-hydrÂoxy-1-phenylÂethyl]ammonium chloride
In the title compound, C18H24NO2
+·Clâ, the absolute configuration of the new stereogenic centre (the C atom with a CH2OH substituent) was unambiguously determined to have an R configuration. The dihedral angle between the two aromatic rings is 30.82â
(2)°. InterÂmolecular NâHâŻCl and OâHâŻCl hydrogen bonds and intraÂmolecular NâHâŻO hydrogen bonds stabilize the crystal structure
The effect of the oxygen ratio control of DC reactive magnetron sputtering on as-deposited non stoichiometric NiO thin films
Non-stoichiometric Ni1-xO thin films were prepared on glass substrate by direct current reactive magnetron sputtering in a large range of oxygen partial pressure (0â€pO2â€1Pa). The dependence of the deposited film structure and properties on oxygen stoichiometry were systematically analyzed by X-ray diffraction, X-ray reflectivity, X-ray photoemission spectroscopy, Raman spectroscopy, atomic force microscopy, UVâvis measurements and electrical transport properties measurements. The deposition rates, surface morphology and opto-electrical properties are very sensitive to the oxygen partial pressure lower than 0.05Pa due to the presence of metallic nickel cluster phase determined by X-ray diffraction, X-ray reflectivity and XPS spectroscopy. Presence of nanocrystallized NiO phase was highlighted even for pO2=0Pa. For pO2>0.05Pa, only the NiO phase was detected. Progressive appearance of Ni3+ species is characterized by a fine increase of the lattice parameter and (111) preferred orientation determined by grazing angle X-ray diffraction, fine increase of the X-ray reflectivity critical angle, displacement of the Ni 2p3/2 signal towards lower energy, significant increase of the electrical conductivity and decrease of the total transmittance. Quantification of Ni3+ by XPS method is discussed. We also showed that the use of Raman spectroscopy was relevant for demonstrating the presence of Ni3+ in the Ni1-xO thin films
Optimized properties of innovative ElectroChromic Device using ITO / Ag / ITO electrodes
The âDielectric/Metal/Dielectricâ (DMD) stacked films being used as transparent and conductive (TC) electrodes, have demonstrated excellent application in the ElectroChromic (EC) process and devices. In this work, multilayers (IAI) made of 50âŻnm of Indium Tin Oxide (ITO)/5âŻnm of metallic silver (Ag)/30âŻnm of ITO that exhibit band-gap, low resistance of 7.4âŻÎ© and the high figure of merit of 9.9âŻĂâŻ10â3âŻÎ©â1 were introduced in a complete five-layer Glass/IAI/NiOx/LiClO4-PC-PMMA/WO3/IAI/Glass ElectroChromic Device (ECD). The single IAI electrode as well as the two actives EC layers Glass/IAI/NiOx and Glass/IAI/WO3 were firstly characterized for their TC and EC properties respectively. Then, the EC properties of the complete five-layer ECD were analyzed. Fast response time (2.02âŻs for the bleaching and 2.25âŻs for complete coloration), wide optical modulation in the visible light region (âŒ55% at 550âŻnm), long lifetime (more than 6000âŻs), large capacity and good stability as well as high coloration efficiency (31.7âŻcm2âŻCâ1) were obtained. The improved EC performance of ECD were related to the good electrical and optical properties of IAI electrode
Antecedent infections in Guillain-Barré syndrome: a single-center, prospective study
Objective: To investigate the spectrum of antecedent infections in Chinese patients with Guillain-Barré syndrome (GBS) and analyze the infecti
The International Surface Pressure Databank version 2
The International Surface Pressure Databank (ISPD) is the world's largest collection of global surface and sea-level pressure observations. It was developed by extracting observations from established international archives, through international cooperation with data recovery facilitated by the Atmospheric Circulation Reconstructions over the Earth (ACRE) initiative, and directly by contributing universities, organizations, and countries. The dataset period is currently 1768â2012 and consists of three data components: observations from land stations, marine observing systems, and tropical cyclone best track pressure reports. Version 2 of the ISPD (ISPDv2) was created to be observational input for the Twentieth Century Reanalysis Project (20CR) and contains the quality control and assimilation feedback metadata from the 20CR. Since then, it has been used for various general climate and weather studies, and an updated version 3 (ISPDv3) has been used in the ERA-20C reanalysis in connection with the European Reanalysis of Global Climate Observations project (ERA-CLIM). The focus of this paper is on the ISPDv2 and the inclusion of the 20CR feedback metadata. The Research Data Archive at the National Center for Atmospheric Research provides data collection and access for the ISPDv2, and will provide access to future versions
The state of the Martian climate
60°N was +2.0°C, relative to the 1981â2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
State of the climate in 2018
In 2018, the dominant greenhouse gases released into Earthâs atmosphereâcarbon dioxide, methane, and nitrous oxideâcontinued their increase. The annual global average carbon dioxide concentration at Earthâs surface was 407.4 ± 0.1 ppm, the highest in the modern instrumental record and in ice core records dating back 800 000 years. Combined, greenhouse gases and several halogenated gases contribute just over 3 W mâ2 to radiative forcing and represent a nearly 43% increase since 1990. Carbon dioxide is responsible for about 65% of this radiative forcing. With a weak La Niña in early 2018 transitioning to a weak El Niño by the yearâs end, the global surface (land and ocean) temperature was the fourth highest on record, with only 2015 through 2017 being warmer. Several European countries reported record high annual temperatures. There were also more high, and fewer low, temperature extremes than in nearly all of the 68-year extremes record. Madagascar recorded a record daily temperature of 40.5°C in Morondava in March, while South Korea set its record high of 41.0°C in August in Hongcheon. Nawabshah, Pakistan, recorded its highest temperature of 50.2°C, which may be a new daily world record for April. Globally, the annual lower troposphere temperature was third to seventh highest, depending on the dataset analyzed. The lower stratospheric temperature was approximately fifth lowest. The 2018 Arctic land surface temperature was 1.2°C above the 1981â2010 average, tying for third highest in the 118-year record, following 2016 and 2017. Juneâs Arctic snow cover extent was almost half of what it was 35 years ago. Across Greenland, however, regional summer temperatures were generally below or near average. Additionally, a satellite survey of 47 glaciers in Greenland indicated a net increase in area for the first time since records began in 1999. Increasing permafrost temperatures were reported at most observation sites in the Arctic, with the overall increase of 0.1°â0.2°C between 2017 and 2018 being comparable to the highest rate of warming ever observed in the region. On 17 March, Arctic sea ice extent marked the second smallest annual maximum in the 38-year record, larger than only 2017. The minimum extent in 2018 was reached on 19 September and again on 23 September, tying 2008 and 2010 for the sixth lowest extent on record. The 23 September date tied 1997 as the latest sea ice minimum date on record. First-year ice now dominates the ice cover, comprising 77% of the March 2018 ice pack compared to 55% during the 1980s. Because thinner, younger ice is more vulnerable to melting out in summer, this shift in sea ice age has contributed to the decreasing trend in minimum ice extent. Regionally, Bering Sea ice extent was at record lows for almost the entire 2017/18 ice season. For the Antarctic continent as a whole, 2018 was warmer than average. On the highest points of the Antarctic Plateau, the automatic weather station Relay (74°S) broke or tied six monthly temperature records throughout the year, with August breaking its record by nearly 8°C. However, cool conditions in the western Bellingshausen Sea and Amundsen Sea sector contributed to a low melt season overall for 2017/18. High SSTs contributed to low summer sea ice extent in the Ross and Weddell Seas in 2018, underpinning the second lowest Antarctic summer minimum sea ice extent on record. Despite conducive conditions for its formation, the ozone hole at its maximum extent in September was near the 2000â18 mean, likely due to an ongoing slow decline in stratospheric chlorine monoxide concentration. Across the oceans, globally averaged SST decreased slightly since the record El Niño year of 2016 but was still far above the climatological mean. On average, SST is increasing at a rate of 0.10° ± 0.01°C decadeâ1 since 1950. The warming appeared largest in the tropical Indian Ocean and smallest in the North Pacific. The deeper ocean continues to warm year after year. For the seventh consecutive year, global annual mean sea level became the highest in the 26-year record, rising to 81 mm above the 1993 average. As anticipated in a warming climate, the hydrological cycle over the ocean is accelerating: dry regions are becoming drier and wet regions rainier. Closer to the equator, 95 named tropical storms were observed during 2018, well above the 1981â2010 average of 82. Eleven tropical cyclones reached SaffirâSimpson scale Category 5 intensity. North Atlantic Major Hurricane Michaelâs landfall intensity of 140 kt was the fourth strongest for any continental U.S. hurricane landfall in the 168-year record. Michael caused more than 30 fatalities and 6 billion (U.S. dollars) in damages across the Philippines, Hong Kong, Macau, mainland China, Guam, and the Northern Mariana Islands. Tropical Storm Son-Tinh was responsible for 170 fatalities in Vietnam and Laos. Nearly all the islands of Micronesia experienced at least moderate impacts from various tropical cyclones. Across land, many areas around the globe received copious precipitation, notable at different time scales. Rodrigues and RĂ©union Island near southern Africa each reported their third wettest year on record. In Hawaii, 1262 mm precipitation at WaipÄ Gardens (Kauai) on 14â15 April set a new U.S. record for 24-h precipitation. In Brazil, the city of Belo Horizonte received nearly 75 mm of rain in just 20 minutes, nearly half its monthly average. Globally, fire activity during 2018 was the lowest since the start of the record in 1997, with a combined burned area of about 500 million hectares. This reinforced the long-term downward trend in fire emissions driven by changes in land use in frequently burning savannas. However, wildfires burned 3.5 million hectares across the United States, well above the 2000â10 average of 2.7 million hectares. Combined, U.S. wildfire damages for the 2017 and 2018 wildfire seasons exceeded $40 billion (U.S. dollars)
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Towards a more reliable historical reanalysis: improvements for version 3 of the Twentieth Century Reanalysis system
Historical reanalyses that span more than a century are needed for a wide range of studies, from understanding largeâscale climate trends to diagnosing the impacts of individual historical extreme weather events. The Twentieth Century Reanalysis (20CR) Project is an effort to fill this need. It is supported by the National Oceanic and Atmospheric Administration (NOAA), the Cooperative Institute for Research in Environmental Sciences (CIRES), and the U.S. Department of Energy (DOE), and is facilitated by collaboration with the international Atmospheric Circulation Reconstructions over the Earth initiative. 20CR is the first ensemble of subâdaily global atmospheric conditions spanning over 100 years. This provides a best estimate of the weather at any given place and time as well as an estimate of its confidence and uncertainty. While extremely useful, version 2c of this dataset (20CRv2c) has several significant issues, including inaccurate estimates of confidence and a global sea level pressure bias in the midâ19th century. These and other issues can reduce its effectiveness for studies at many spatial and temporal scales. Therefore, the 20CR system underwent a series of developments to generate a significant new version of the reanalysis. The version 3 system (NOAAâCIRESâDOE 20CRv3) uses upgraded data assimilation methods including an adaptive inflation algorithm; has a newer, higherâresolution forecast model that specifies dry air mass; and assimilates a larger set of pressure observations. These changes have improved the ensembleâbased estimates of confidence, removed spinâup effects in the precipitation fields, and diminished the seaâlevel pressure bias. Other improvements include more accurate representations of storm intensity, smaller errors, and largeâscale reductions in model bias. The 20CRv3 system is comprehensively reviewed, focusing on the aspects that have ameliorated issues in 20CRv2c. Despite the many improvements, some challenges remain, including a systematic bias in tropical precipitation and timeâvarying biases in southern highâlatitude pressure fields
Transcriptomics reveals the molecular processes of light-induced rapid darkening of the non-obligate cave dweller Oreolalax rhodostigmatus (Megophryidae, Anura) and their genetic basis of pigmentation strategy
Abstract Background Vertebrates use different pigmentation strategies to adapt to various environments. A large amount of research has been done on disclosing the mechanisms of pigmentation strategies in vertebrates either under light, or, living in constant darkness. However, less attention has been paid to non-obligate, darkness dwellers. Red-spotted toothed toads Oreolalax rhodostigmatus (Megophryidae; Anura) from the karst mountainous region of southwestern China are non-obligate cave dwellers. Most tadpoles of the species possess transparent skin as they inhabit the dark karst caves. But remarkably, the transparent tadpoles can darken just within 15Â h once exposed to light. Obviously, it is very significant to reveal molecular mechanisms of the unexpected rapid-darkening phenomenon. Results We compared the transcriptomes of O. rhodostigmatus tadpoles with different durations of light exposure to investigate the cellular processes and potential regulation signals for their light-induced rapid darkening. Genes involved in melanogenesis (i.e. TYR, TYRP1 and DCT) and melanocyte proliferation, as well as their transcriptional factor (MITF), showed light-induced transcription, suggesting a dominating role of morphological color change (MCC) in this process. Transcription of genes related to growth factor, MAPK and PI3K-Akt pathways increased with time of light exposure, suggesting that light could induce significant growth signal, which might facilitate the rapid skin darkening. Most importantly, an in-frame deletion of four residues was identified in O. rhodostigmatus melanocortin-1 receptor (MC1R), a critical receptor in MCC. This deletion results in a more negatively charged ligand pocket with three stereo-tandem aspartate residues. Such structural changes likely decrease the constitutive activity of MC1R, but increase its ligands-dependent activity, thus coordinating pigment regression and rapid melanogenesis in the dark and light, respectively. Conclusion Our study suggested that rapid MCC was responsible for the light-induced rapid darkening of O. rhodostigmatus tadpoles. Genetic mutations of MC1R in them could explain how these non-obligate cave dwellers coordinate pigment regression and robust melanogenesis in darkness and light, respectively. To our knowledge, this is the first study that reports the association between pigmentation phenotype adaptation and MC1R mutations in amphibians and/or in non-obligate cave dwellers
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