Read by QxMD icon Read

Arctic Sun

Indrani Roy
This study investigates the role of the eleven-year solar cycle on the Arctic climate during 1979-2016. It reveals that during those years, when the winter solar sunspot number (SSN) falls below 1.35 standard deviations (or mean value), the Arctic warming extends from the lower troposphere to high up in the upper stratosphere and vice versa when SSN is above. The warming in the atmospheric column reflects an easterly zonal wind anomaly consistent with warm air and positive geopotential height anomalies for years with minimum SSN and vice versa for the maximum...
March 20, 2018: Scientific Reports
Stig Andersen, Paneeraq Noahsen, Karsten F Rex, Inuuteq Fleischer, Nadja Albertsen, Marit E Jørgensen, Louise K Schæbel, Mogens B Laursen
Ca homoeostasis is important to human health and tightly controlled by powerful hormonal mechanisms that display ethnic variation. Ethnic variations could occur also in Arctic populations where the traditional Inuit diet is low in Ca and sun exposure is limited. We aimed to assess factors important to parathyroid hormone (PTH) and Ca in serum in Arctic populations. We included Inuit and Caucasians aged 50-69 years living in the capital city in West or in rural East Greenland. Lifestyle factors were assessed by questionnaires...
February 2018: British Journal of Nutrition
Simona Retelletti Brogi, Sun-Yong Ha, Kwanwoo Kim, Morgane Derrien, Yun Kyung Lee, Jin Hur
Sea ice contains a large amount of dissolved organic matter (DOM), which can be released into the ocean once it melts. In this study, Arctic sea ice DOM was characterized for its optical (fluorescence) properties as well as the molecular sizes and composition via size exclusion chromatography and Fourier transformation ion cyclotron resonance mass spectrometry (FT-ICR MS). Ice cores were collected along with the underlying seawater samples in Cambridge Bay, an Arctic area experiencing seasonal ice formation...
June 15, 2018: Science of the Total Environment
Martin Ludvigsen, Jørgen Berge, Maxime Geoffroy, Jonathan H Cohen, Pedro R De La Torre, Stein M Nornes, Hanumant Singh, Asgeir J Sørensen, Malin Daase, Geir Johnsen
Light is a major cue for nearly all life on Earth. However, most of our knowledge concerning the importance of light is based on organisms' response to light during daytime, including the dusk and dawn phase. When it is dark, light is most often considered as pollution, with increasing appreciation of its negative ecological effects. Using an Autonomous Surface Vehicle fitted with a hyperspectral irradiance sensor and an acoustic profiler, we detected and quantified the behavior of zooplankton in an unpolluted light environment in the high Arctic polar night and compared the results with that from a light-polluted environment close to our research vessels...
January 2018: Science Advances
Petra Sonder, Gladys N Janssens, Albertus Beishuizen, Connie L Henry, Jon C Rittenberger, Clifton W Callaway, Cameron Dezfulian, Kees H Polderman
BACKGROUND: Mild therapeutic hypothermia (32-36 °C) is associated with improved outcomes in patients with brain injury after cardiac arrest (CA). Various devices are available to induce and maintain hypothermia, but few studies have compared the performance of these devices. We performed a prospective study to compare four frequently used cooling systems in inducing and maintaining hypothermia followed by controlled rewarming. METHODS: We performed a prospective multi-centered study in ten ICU's in three hospitals within the UPMC health system...
March 2018: Resuscitation
Xiaoli Wang, Kunlai Sun, Bin Wang
Two new pimarane diterpenes, libertellenone M (1) and libertellenone N (2), together with five known compounds were isolated from the culture extract of Eutypella sp. D-1 derived from high-latitude soil of the Arctic. The structures of these compounds were determined by spectroscopic data as well as experimental and calculated electronic circular dichroism (ECD) analysis. Antimicrobial and cytotoxic activities of the isolated compounds were evaluated. Compound 3 exhibited weak antibacterial activity against Escherichia coli, Bacillus subtilis, and Vibrio vulnificus, each with MIC values of 16 μg/mL...
February 2018: Chemistry & Biodiversity
Yashu Chen, Bijun Xie, Jifang Yang, Jigang Chen, Zhida Sun
Rhodococcus sp. B7740 is a newfound bacterium which was isolated from 25m deep seawater in the arctic. In this paper, Rhodococcus sp. B7740 was firstly discovered to produce abundant natural isoprenoids, including ubiquinone-4(UQ-4), 13 kinds of menaquinones, three rare aromatic carotenoids and more than one common carotenoid. These compounds were identified by UV-Visible, HPLC-APCI-MS/MS and HRMS spectra. Results demonstrated that Rhodococcus sp. B7740 might be a worthy source of natural isoprenoids especially for scarce aromatic carotenoids...
February 1, 2018: Food Chemistry
David Hazlerigg, Arnoldus Schytte Blix, Karl-Arne Stokkan
At temperate latitudes, the annual cycle of day length synchronizes circannual rhythms, and, in mammals, this is mediated via nocturnal production of the pineal hormone melatonin, proportional to the length of the night. Here, we studied circannual synchronization in an arctic species, the reindeer (Rangifer tarandus tarandus), which ceases to produce a rhythmic melatonin signal when it is exposed to extended periods of continuous midwinter darkness, and continuous midsummer light. Using food intake, antler growth and moult as endpoints, we demonstrate that when animals living at 70°N are transferred from natural photoperiods in late autumn to either continuous light or continuous darkness, they undergo a conspicuous acceleration of the circannual program...
September 1, 2017: Journal of Experimental Biology
Wei-Wei Ni, Li-Bing Wang, Yan-Jun Zhou, Meng-Da Cao, Wen Huang, Miao Guo, Chun-Mei Ji, Jin-Lu Sun, Ji-Fu Wei
Platanus acerifolia (P. acerifolia) is an important cause of pollinosis in cities. The use of allergen extracts on patients with allergic diseases is the most commonly applied method to attempt to treat pollinosis. Pla a 3, a non‑specific lipid transfer protein, is a major allergen present in P. acerifolia pollen extracts. In the present study, the Pla a 3 gene was sub‑cloned into a pSUMO‑Mut vector using Stu I and Xho I sites and transformed into the Arctic Express™ (DE3) RP E. coli host strain...
September 2017: Molecular Medicine Reports
Ki-Hwa Kim, Chang Woo Lee, Bikash Dangi, Sun-Ha Park, Hyun Park, Tae-Jin Oh, Jun Hyuck Lee
Bacterial cytochrome P450 (CYP) steroid hydroxylases are effectively useful in the pharmaceutical industry for introducing hydroxyl groups to a wide range of steroids. We found a putative CYP steroid hydroxylase ( Ba CYP106A2) from the bacterium Bacillus sp. PAMC 23377 isolated from Kara Sea of the Arctic Ocean, showing 94% sequence similarity with Bm CYP106A2 ( Bacillus megaterium ATCC 13368). In this study, soluble Ba CYP106A2 was overexpressed to evaluate its substrate-binding activity. The substrate affinity ( K d value) to 4-androstenedione was 387 ± 37 µM...
August 28, 2017: Journal of Microbiology and Biotechnology
David K A Barnes, Geraint A Tarling
Most of Earth's surface is blue or white, but how much of each would depend on the time of observation. Our planet has been through phases of snowball (all frozen), greenhouse (all liquid seas) and icehouse (frozen and liquid). Even during current icehouse conditions, the extent of ice versus water has changed considerably between ice ages and interglacial periods. Water has been vital for life on Earth and has driven and been influenced by transitions between greenhouse and icehouse. However, neither the possession of water nor having liquid and frozen seas are unique to Earth (Figure 1)...
June 5, 2017: Current Biology: CB
Susanne Åkesson, Giuseppe Bianco
Bird migration has fascinated humans for centuries and routes crossing the globe are now starting to be revealed by advanced tracking technology. A central question is what compass mechanism, celestial or geomagnetic, is activated during these long flights. Different approaches based on the geometry of flight routes across the globe and route simulations based on predictions from compass mechanisms with or without including the effect of winds have been used to try to answer this question with varying results...
July 2017: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
Marjo Palviainen, Jukka Pumpanen, Frank Berninger, Kaisa Ritala, Baoli Duan, Jussi Heinonsalo, Hui Sun, Egle Köster, Kajar Köster
Fire is a major natural disturbance factor in boreal forests, and the frequency of forest fires is predicted to increase due to climate change. Nitrogen (N) is a key determinant of carbon sequestration in boreal forests because the shortage of N limits tree growth. We studied changes in N pools and fluxes, and the overall N balance across a 155-year non stand-replacing fire chronosequence in sub-arctic Pinus sylvestris forests in Finland. Two years after the fire, total ecosystem N pool was 622 kg ha-1 of which 16% was in the vegetation, 8% in the dead biomass and 76% in the soil...
2017: PloS One
Fanglu Xu, Haiyan Jin, Zhongqiang Ji, Jianfang Chen, Pei Sun Loh
In this study, lignin-derived phenols were used to determine the sources and distribution of sedimentary organic matter along the northern Bering Sea and Chukchi Sea of the Arctic Ocean. The lignin parameter syringyl/vanillyl (S/V) and cinnamyl/vanillyl (C/V) ratios are used to indicate vegetation sources; and the ratios of vanillic acid/vanillin, (Ad/Al)v and syringic acid/syringaldehyde, (Ad/Al)s are used as indicators of lignin diagenesis. Results showed the predominance of woody gymnosperm signal at the easternmost location in the northern Bering Sea, a mixture of refractory non-woody angiosperm and fresher gymnosperm tissues in the Chukchi Sea, and signal of fresher woody gymnosperm tissues in the northernmost locations in the Chukchi Sea...
February 2017: Journal of Environmental Sciences (China)
Gurpreet Singh Aujla, Premkumar Nattanmai, Keerthivaas Premkumar, Christopher R Newey
Fever increases mortality and morbidity and length of stay in neurocritically ill patients. Various methods are used in the neuroscience intensive care unit (NSICU) to control fever. Two such methods involve the Arctic Sun hydrogel wraps and the Gaymar cooling wraps. The purpose of our study was to compare these two methods in neurocritical care patients who had temperature >37.5°C for more than three consecutive hours and that was refractory to standard treatments. Data of patients requiring cooling wraps for treatment of hyperthermia at an NSICU at an academic, tertiary referral center were retrospectively reviewed...
September 2017: Therapeutic Hypothermia and Temperature Management
Hui Peng, Chunli Chen, Jenna Cantin, David M V Saunders, Jianxian Sun, Song Tang, Garry Codling, Markus Hecker, Steve Wiseman, Paul D Jones, An Li, Karl J Rockne, Neil C Sturchio, Minghong Cai, John P Giesy
The majority of halogenated organic compounds present in the environment remain unidentified. To address this data gap, we recently developed an untargeted method (data-independent precursor isolation and characteristic fragment; DIPIC-Frag) for identification of unknown organo-bromine compounds. In this study, the method was adapted to enable untargeted screening of natural and synthetic organo-iodine compounds (NSOICs) in sediments. A total of 4,238 NSOIC peaks were detected in sediments from Lake Michigan...
September 20, 2016: Environmental Science & Technology
Damien Tran, Mohamedou Sow, Lionel Camus, Pierre Ciret, Jorgen Berge, Jean-Charles Massabuau
Although the prevailing paradigm has held that the polar night is a period of biological quiescence, recent studies have detected noticeable activity levels in marine organisms. In this study, we investigated the circadian rhythm of the scallop Chlamys islandica by continuously recording the animal's behaviour over 3 years in the Arctic (Svalbard). Our results showed that a circadian rhythm persists throughout the polar night and lasts for at least 4 months. Based on observations across three polar nights, we showed that the robustness and synchronicity of the rhythm depends on the angle of the sun below the horizon...
2016: Scientific Reports
Wenhan Cheng, Liguang Sun, Linda E Kimpe, Mark L Mallory, John P Smol, Lauren R Gallant, Jinping Li, Jules M Blais
Seabirds are major vertebrates in the coastal ecosystems of the Canadian High Arctic, where they transport substantial amounts of marine-derived nutrients and pollutants from oceans to land by depositing guano and stomach oils to their nesting area, which often includes nearby freshwater ponds. Here we present novel indicators for evaluating the impact of seabirds on freshwater ecosystems. The ratio of cholesterol/(cholesterol + sitosterol) in pond sediments showed significant enrichment near a nesting colony of northern fulmars (Fulmarus glacialis) and was significantly correlated with ornithogenic enrichment of sediment as determined by sedimentary δ(15)N...
September 6, 2016: Environmental Science & Technology
Natalie T Boelman, Troy S Magney, Barry A Logan, Kevin L Griffin, Jan U H Eitel, Heather Greaves, Case M Prager, Lee A Vierling
As the Arctic warms, tundra vegetation is becoming taller and more structurally complex, as tall deciduous shrubs become increasingly dominant. Emerging studies reveal that shrubs exhibit photosynthetic resource partitioning, akin to forests, that may need accounting for in the "big leaf" net ecosystem exchange models. We conducted a lab experiment on sun and shade leaves from S. pulchra shrubs to determine the influence of both constitutive (slowly changing bulk carotenoid and chlorophyll pools) and facultative (rapidly changing xanthophyll cycle) pigment pools on a suite of spectral vegetation indices, to devise a rapid means of estimating within canopy resource partitioning...
September 2016: Oecologia
Arnoldus Schytte Blix
This Review presents a broad overview of adaptations of truly Arctic and Antarctic mammals and birds to the challenges of polar life. The polar environment may be characterized by grisly cold, scarcity of food and darkness in winter, and lush conditions and continuous light in summer. Resident animals cope with these changes by behavioural, physical and physiological means. These include responses aimed at reducing exposure, such as 'balling up', huddling and shelter building; seasonal changes in insulation by fur, plumage and blubber; and circulatory adjustments aimed at preservation of core temperature, to which end the periphery and extremities are cooled to increase insulation...
April 15, 2016: Journal of Experimental Biology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"