pinecone/core-2020-05-10-deduplication huggingface dataset:
Effect of Terrain Characteristics on Soil Organic Carbon and Total Nitrogen Stocks in Soils of Herschel Island, Western Canadian Arctic

Permafrost landscapes experience different disturbances and store large amounts of organic matter, which may become a source of greenhouse gases upon permafrost degradation. We analysed the influence of terrain and geomorphic disturbances (e.g. soil creep, active-layer detachment, gullying, thaw slumping, accumulation of fluvial deposits) on soil organic carbon (SOC) and total nitrogen (TN) storage using 11 permafrost cores from Herschel Island, western Canadian Arctic. Our results indicate a strong correlation between SOC storage and the topographic wetness index. Undisturbed sites stored the majority of SOC and TN in the upper 70 cm of soil. Sites characterised by mass wasting showed significant SOC depletion and soil compaction, whereas sites characterised by the accumulation of peat and fluvial deposits store SOC and TN along the whole core. We upscaled SOC and TN to estimate total stocks using the ecological units determined from vegetation composition, slope angle and the geomorphic disturbance regime. The ecological units were delineated with a supervised classification based on RapidEye multispectral satellite imagery and slope angle. Mean SOC and TN storage for the uppermost 1 m of soil on Herschel Island are 34.8 kg C m-2 and 3.4 kg N m-2, respectively. Copyright © 2015 John Wiley & Sons, Ltd
Permafrost Thaw and Liberation of Inorganic Nitrogen in Eastern Siberia

The currently observed climate warming will lead to widespread degradation of near-surface permafrost, which may release substantial amounts of inorganic nitrogen (N) into arctic ecosystems. We studied 11 soil profiles at three different sites in arctic eastern Siberia to assess the amount of inorganic N stored in arctic permafrost soils. We modelled the potential thickening of the active layer for these sites using the CryoGrid2 permafrost model and representative concentration pathways (RCPs) 4.5 (a stabilisation scenario) and 8.5 (a business as usual emission scenario, with increasing carbon emissions). The modelled increases in active-layer thickness (ALT) were used to estimate potential annual liberation of inorganic N from permafrost soils during the course of climate change. We observed significant stores of inorganic ammonium in permafrost, up to 40-fold higher than in the active layer. The modelled increase in ALT under the RCP8.5 scenario can result in substantial liberation of N, reaching values up to the order of magnitude of annual fixation of atmospheric N in arctic soils. However, the thaw-induced liberation of N represents only a small flux in comparison with the overall ecosystem N cycling
Microbial controls on methane fluxes from a polygonal tundra of the Lena Delta, Siberia

Permafrost soils of high-latitude wetlands are an important source of atmospheric methane. In order to improve our understanding of the large seasonal fluctuations of trace gases, we measured the CH4 fluxes as well as the fundamental processes of CH4 production and CH4 oxidation under in situ conditions in a typical polygon tundra in the Lena Delta, Siberia. Net CH4 fluxes were measured from the polygon depression and from the polygon rim from the end of May to the beginning of September 1999. The mean flux rate of the depression was 53.2 ± 8.7 mg CH4 m−2 d−1 with maximum in mid-July (100–120 mg CH4 m−2 d−1), whereas the mean flux rate of the dryer rim part of the polygon was 4.7 ± 2.5 CH4 m−2 d−1. The microbial CH4 production and oxidation showed significant differences during the vegetation period. The CH4 production in the upper soil horizon of the polygon depression was about 10 times higher (38.9 ± 2.9 nmol CH4 h−1 g−1) in July than in August (4.7 ± 1.3 nmol CH4 h−1 g−1). The CH4 oxidation behaved exactly in reverse: the oxidation rate of the upper soil horizon was low (1.9 ± 0.3 nmol CH4 h−1 g−1) in July compared to the activity in August (max. 7.0 ± 1.3 nmol CH4 h−1 g−1). The results indicated clearly an interaction between the microbiological processes with the observed seasonal CH4 fluctuations. However, the CH4 production is primarily substrate dependent, while the oxidation is dependent on the availability of oxygen. The temperature plays only a minor role in both processes, probably because the organisms are adapted to extreme temperature conditions of the permafrost. For the understanding of the carbon dynamics in permafrost soils, a differentiated small-scale view of the microbiological processes and the associated modes of CH4 fluxes is necessary, especially at key locations such as the Siberian Arctic
Simulation of freezing-thawing cycles in a permafrost microcosm for assessing microbial methane production under extreme conditions

The microbial process of methane (CH4) production during the back-freezing of permafrost soils in autumn and the future fate of produced CH4 in the thawing phase of the following spring are not well understood. Long-term CH4 flux studies in the Lena Delta (Siberia) indicate that back-stored CH4 adds to the emission of newly-produced CH4 at the beginning of the vegetation period. Further field analysis shows that microbial CH4 production already occurs at in situ temperatures of around 1°C in the bottom layer of the soil. Therefore, a permafrost microcosm was developed to simulate the influence of the annual freezing-thawing cycles on the CH4 fluxes in the active layer of permafrost soils. Two cryostats ensure independent freezing and thawing the top and the bottom of the microcosm to simulate different field conditions. The CH4 concentration (Rhizon soil moisture samplers), the soil temperature (film platinum resistance temperature detectors [RTDs]) and the soil water content (time domain reflectometry) are analysed in different depths of the microcosm during the simulation in addition to the concentration of emitted CH4 in the headspace of the microcosm. The data obtained contribute to the understanding of microbial processes and CH4 fluxes in permafrost environments in the autumn and early winter
Frost boils and soil ice content: field observations

Our aim is to measure and explain the seasonal changes in soil ice content in the frost boils of Galbraith Lake, Alaska. Instruments were installed in a frost boil to monitor the ground surface position and soil state over a period of 4 years. By comparing the subsidence and thaw rates, we calculate the soil ice content as a function of depth. Measured soil temperatures, liquid water contents and bulk apparent thermal conductivities are used to estimate latent heat production and release in the soil. The frost boil heaves during freezing and settles during thaw while the surrounding tundra heaves negligibly, but subsides measurably. Despite large changes in freezing rates from year to year, total heave and its distribution across the frost boil are similar between years. Winter air temperature and snow depth influence the freezing rate and ice distribution as a function of depth, but not the overall heave. This suggests that heave is controlled by water availability rather than the rate of heat removal from the soil. Areal ground subsidence rates between 2 and 5 cm/yr are due to the disappearance of ice at the base of the active layer, raising the possibility of ongoing thermokarst expansion around Galbraith Lake
Syngenetic sand veins and anti-syngenetic sand wedges, Tuktoyaktuk Coastlands, western Arctic Canada

Sand-sheet deposits of full-glacial age in the Tuktoyaktuk Coastlands, western Arctic Canada, contain syngenetic sand veins 1-21 cm wide and sometimes exceeding 9 m in height. Their tall and narrow, chimney-like morphology differs from that of known syngenetic ice wedges and indicates an unusually close balance between the rate of sand-sheet aggradation and the frequency of thermal-contraction cracking. The sand sheets also contain rejuvenated (syngenetic) sand wedges that have grown upward from an erosion surface. By contrast, sand sheets of postglacial age contain few or sometimes no intraformational sand veins and wedges, suggesting that the climatic conditions were unfavourable for thermal-contraction cracking. Beneath a postglacial sand sheet near Johnson Bay, sand wedges with unusually wide tops (3.9 m) extend down from a prominent erosion surface. The wedges grew vertically downward during deflation of the ground surface, and represent anti-syngenetic wedges. The distribution of sand veins and wedges within the sand sheets indicates that the existence of continuous permafrost during sand-sheet aggradation can be inferred confidently only during full-glacial conditions
Thermal State of Permafrost and Active-layer Monitoring in the Antarctic: Advances During the International Polar Year 2007-2009

Results obtained during the International Polar Year (IPY) on the thermal state of permafrost and the active layer in the Antarctic are presented, forming part of ANTPAS ('Antarctic Permafrost and Soils'), which was one of the key projects developed by the International Permafrost Association and the Scientific Committee for Antarctic Research for the IPY. The number of boreholes for permafrost and active-layer monitoring was increased from 21 to 73 during the IPY, while CALM-S sites to monitor the active layer were increased from 18 to 28. Permafrost temperatures during the IPY were slightly below 0 degrees C in the South Shetlands near sea-level, showing that this area is near the climatic boundary of permafrost and has the highest sensitivity to climate change in the region. Permafrost temperatures were much lower in continental Antarctica: from the coast to the interior and with increasing elevation they ranged between -13.3 degrees C and 18.6 degrees C in Northern Victoria Land, from -17.4 degrees C to -22.5 degrees C in the McMurdo Dry Valleys, and down to -23.6 degrees C at high elevation on Mount Fleming (Ross Island). Other monitored regions in continental Antarctica also showed cold permafrost: Queen Maud Land exhibited values down to -17.8 degrees C on nunataks, while in Novolazar-evskaya (Schirmacher Oasis) at 80 m a.s.l. the permafrost temperature was -8.3 degrees C. The coastal stations of Molodeznaya at Enderby Land showed permafrost temperatures of -9.8 degrees C, Larsemann Hills Progress Station in the Vestfold Hills region-recorded -8.5 degrees C, and Russkaya in Marie Byrd Land, 10.4 degrees C. This snapshot obtained during. the IPY shows that the range of ground temperatures in the Antarctic is greater than in the Arctic
Experimental Study on Powder Flowability Using Vibration Shear Tube Method

The flowability of powders with different mass median diameters ranging from micrometers to nanometers was measured using the vibration shear tube method. In the measurement system used in this study, the powder was discharged through a narrow gap between a vibrating tube edge and a flat bottom surface, where each particle could experience high shear forces to overcome the adhesion and friction forces. The vibration amplitude was increased during the measurement, and the mass of particles discharged was measured at constant time intervals. From the relationship between the mass flow rate and the vibration acceleration, static and dynamic properties of the powders were evaluated using the critical vibration acceleration, characteristic mass flow rate, and gradient of mass flow rate. The correlation between the static and dynamic properties was studied in detail
Influence of the Morphology of Lysozyme-Shelled Microparticles on the Cellular Association, Uptake, and Degradation in Human Breast Adenocarcinoma Cells.

he ultrasound-assisted self-assembly and cross-linking of lysozyme at the water–air and water–perfluorohexane interfaces are shown to produce lysozyme-shelled hollow microbubbles (LSMBs) and microcapsules (LSMC), respectively. The arrangement of lysozyme at the air–liquid or oil–liquid interfaces is accompanied by changes in the bioactivity and conformational state of the protein. The interaction of LSMB and LSMC with human breast adenocarcinoma cells (SKBR3) is studied. LSMB and LSMC are phagocyted by cells within 2 h without exerting a cytotoxic activity. The cellular internalization kinetics of LSMB and LSMC and the effects on cell cycle are evaluated using flow cytometry. Evidence for the internalization of microparticles and degradation within the cell are also monitored by confocal and scanning electron microscopic analyses. The integrity of cell membrane and cell cycle is not affected by LSMBs and LSMCs uptake. These studies show that the positively charged LSMB and LSMC are not cytotoxic and can be readily internalized and degraded by the SKBR3 cells. LSMBs and LSMCs show a different uptake kinetics and intracellular degradation pattern due to differences in the arrangement of the protein at the air–liquid or oil–liquid interfaces
Flow Synthesis of Plasmonic Gold Nanoshells via a Microreactor

Gold nanoshells with tunable surface plasmon resonances are a promising material for optical and biomedical applications. They are produced through seed-mediated growth, in which gold nanoparticles (AuNPs) are seeded on the core particle surface followed by growth of the gold seeds into a shell. However, synthetic gold nanoshell production is typically a multistep, time-consuming batch-type process, and a simple and scalable process remains a challenge. In the present study, a continuous flow process for the seed-mediated growth of silica–gold nanoshells is established by exploiting the excellent mixing performance of a microreactor. In the AuNP-seeding step, the reduction of gold ions in the presence of core particles in the microreactor enables the one-step flow synthesis of gold-decorated silica particles through heterogeneous nucleation. Flow shell growth is also realized using the microreactor by selecting an appropriate reducing agent. Because self-nucleation in the bulk solution phase is suppressed in the microreactor system, no washing is needed after each step, thus enabling the connection of the microreactors for the seeding and shell growth steps into a sequential flow process to synthesize gold nanoshells. The established system is simple and robust, thus making it a promising technology for producing gold nanoshells in an industrial setting
A Combined Experimental and Theoretical Study on the Formation of Ag Filaments on β-Ag 2 MoO 4  Induced by Electron Irradiation

A combined experimental and theoretical study is presented to understand the novel observed nucleation and early evolution of Ag ﬁ laments on β-Ag 2 MoO 4  crystals, driven by an accelerated electron beam from an electronic micro-scope under high vacuum. The growth process, chemical composition, and the element distribution in these ﬁ laments are analyzed in depth at the nanoscale level using ﬁ eld-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) with energy-dispersive spectros-copy (EDS) characterization. To complement experimental results, chemical stability, structural and electronic aspects have been studied systematically using ﬁ rst-principles electronic structure theory within a quantum theory of atoms in molecules (QTAIM) framework. The Ag nucleation and formation on β-Ag 2 MoO 4  are a result of structural and electronic changes of the AgO 4  tetrahedral cluster as a constituent building block of β-Ag 2 MoO 4 ,  consistent with Ag metallic formation. The formation of Ag ﬁ lament transforms the β-Ag 2 MoO 4  semiconductor from  n-  to  p- type concomitant with the appearance of Ag defects
Investigation of silver nanoparticle assembly following hybridization with different lengths of DNA

Assays involving the controlled assembly of oligonucleotide-functionalised nanoparticles have been widely investigated for the detection of short, specific sequences of DNA. The surface plasmon resonance changes that result from the near-field coupling of the nanoparticles provide a means for investigating formation of these assemblies. For these assays to be effective in practice, there needs to be rapid and efficient hybridisation of the functionalised nanoparticles with target DNA. However, it is known that the hybridisation rate is adversely affected by increased numbers of non-hybridising bases on the target DNA strand. This study investigates the DNA-directed assembly of oligonucleotide-functionalised silver nanoparticles, with the aim of identifying the parameters that will maximise hybridisation efficiency with long target sequences. The study shows that increasing the length of probes from 12 to 24 bases, and orientating them in a tail-to-tail rather than a head-to-tail configuration, results in significantly enhanced hybridisation with a long target sequence. The use of a volume excluding polymer such as dextran sulphate in the buffer also markedly improves hybridisation. This information will prove useful for researchers involved in the design of DNA-mediated nanoparticle assembly assays, particularly for the detection of long sequences of DNA
Inspired Gas Temperature in Ventilated Neonates

The warming and humidification of inspired gases for ventilated neonates are routine. There are no data on the temperature of the gas at the airway opening in ventilated neonates. Is the inspired gas temperature at the airway opening, as expected and set on the humidifier, around 37 degrees C? We aimed to measure temperature at the airway opening and compare this with the circuit temperature. This was an observational study in a neonatal intensive care unit. Twenty-five mechanically ventilated infants were studied. All had humidifiers with chamber temperature set at 36 degrees C and the circuit temperature set at 37 degrees C. Two temperature probes were inserted and rested at the circuit-exit and at the airway opening, and temperatures were measured for 2 min in each infant. At this time, the circuit temperature was also noted. The mean (SD) temperature at the airway opening in infants nursed in incubators was 34.9 (1.2) degrees C, compared with radiant warmers where the mean (SD) was 33.1 (0.5) degrees C. The mean (SD) difference in temperature from the circuit temperature probe to the airway opening was greater under radiant warmers, with a mean (SD) drop of 3.9 (0.6) degrees C compared with a mean (SD) drop of 2.0 (1.3) degrees C in the incubators. In conclusion, the temperature at the circuit temperature probe does not reflect the temperature at the airway opening. Inspired gas temperatures are lower than the expected 37 degrees C with the normal circuits and usual humidifier settings
Early oxygen uptake recovery following exercise testing in children with chronic chest diseases.

addresses: Children's Health and Exercise Research Centre, School of Sport and Health Sciences, University of Exeter, Exeter, Devon, UK.types: Journal Article; Research Support, Non-U.S. Gov'tThis is the author's post-print version of an article published in Pediatric Pulmonology, 2009, Vol. 44, Issue 5, pp. 480 – 488. Copyright © Wiley-Blackwell 2009. The definitive version is available at www3.interscience.wiley.comThe value of exercise testing as an objective measure of disease severity in patients with chronic chest diseases (CCD) is becoming increasingly recognized. The aim of this study was to investigate changes in oxygen uptake (VO2) during early recovery following maximal cardiopulmonary exercise testing (CPXT) in relation to functional capacity and markers of disease severity. Twenty-seven children with CCD (age 12.7 +/- 3.1 years; 17 female) [19 children with Cystic fibrosis (CF) (age 13.4 +/- 3.1 years; 10 female) and 8 with other stable non-CF chest diseases (NON-CF) (age 11.1 +/- 2.2 years; 7 female)] and 27 healthy controls (age 13.2 +/- 3.3 years; 17 female) underwent CPXT on a cycle ergometer. On-line respiratory gas analysis measured VO2 before and during CPXT to peak VO2) (VO2(peak)), and during the first 10 min of recovery. Early VO2 recovery was quantified by the time (sec) to reach 50% of the VO2 (peak) value. Early VO2 recovery was correlated against spirometry [forced expiratory volume in 1 sec (FEV(1)) and forced expiratory flow between 25% and 75% of the forced vital capacity (FEF(25-75))] and aerobic fitness (VO2)(peak)) as a measure of functional capacity. Disease severity was graded in the CF patients by the Shwachman score (SS). Compared to controls, children with CCD demonstrated a significantly reduced VO2(peak) (P = 0.011), FEV(1) (P < 0.001), FEF(25-75) (P < 0.001), and a significantly prolonged early (VO2) recovery (P = 0.024). In the CF patients the SS was significantly correlated with early VO2 recovery (r = -0.63, P = 0.004), FEV(1) (r = 0.72, P = 0.001), and FEF(25-75) (r = 0.57, P = 0.011). In the children with CCD, FEV(1), FEF(25-75), and BMI were not significantly correlated with VO2(peak) or early VO2 recovery. Lung function does not necessarily reflect aerobic fitness and the ability to recover from exercise in these patients. A significant relationship was found between VO2(peak) and early VO2 recovery (r = -0.39, P = 0.044) in the children with CCD, showing that a greater aerobic fitness corresponded with a faster recovery
Surfactant Protein C Gene (SFPTC) Mutation-Associated Lung Disease: High-Resolution Computed Tomography (HRCT) Findings and its Relation to Histological Analysis
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HRCT and histological finding of SFTPC mutations

International audienceAim of the study Determine high-resolution tomography (HRCT) scan characteristics in children with SFTPC mutation and correlate them to histological findings. Patients and Methods This retrospective multicenter study included 15 children (7 females and 8 males) with SFTPC mutations. HRCT scans have been performed in all the children and lung biopsies in 8 children. Results From all signs assessed on initial HRCT scans, ground-glass opacities (n=14, 93 %) and lung cysts (n=6, 40 %) were predominant. Interlobular septal thickening (n=1, 7 %), air space consolidation (n=1, 7 %), paraseptal emphysema (n=2, 13 %), and pulmonary nodules (n=1, 7 %) were also found. Histological analysis revealed accumulation of macrophages in the alveolar lumen, type II pneumocyte hyperplasia, and alveolar septal thickening. Dilatation of the respiratory bronchiole and alveolar duct associated with muscular hyperplasia were also described. Interestingly, lung cysts on HRCT scans were associated with dilatation of terminal bronchioli and alveolar duct in lung biopsies. Conclusion In children with SFTPC mutations, HRCT scan finding were highly correlated to the histological findings and, as such, represent a useful tool to identify patients that may require SFTPC gene sequencing