bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transmembrane TNF–TNFR2 Impairs Th17 Differentiation by Promoting Il2 Expression
Authors: Miller Patrick G. , Bonn Michael B. , McKarns Susan C. 
Published: August 2015

Abstract
The double-edged sword nature by which IL-2 regulates autoimmunity and the unpredictable outcomes of anti-TNF therapy in autoimmunity highlight the importance for understanding how TNF regulates IL-2. Transmembrane TNF (tmTNF) preferentially binds TNFR2, whereas soluble TNF (sTNF) binds TNFR1. We previously showed reduced IL-2 production in TNFR1−/− TNFR2−/− CD4+ T cells. In this study, we generated TNFR1−/−, TNFR2−/−, or TNFR1−/− TNFR2−/− 5C.C7 TCR Il2-GFP mice and report that CD4+ T cell–intrinsic tmTNF/TNFR2 stimulates Il2 promoter activity and Il2 mRNA stability. We further used tmTNF Foxp3 gfp reporter mice and pharmacological TNF blockade in wild-type mice to report a tmTNF/TNFR2 interaction for Il2 expression. IL-17 is critical for host defense, but its overabundance promotes autoimmunity. IL-2 represses Th17 differentiation, but the role for TNFR2 in this process is not well understood. We report elevated expression of TNFR2 under Th17-polarization conditions. Genetic loss-of-function experimental models, as well as selective TNF blockade by etanercept and XPro1595 in wild-type mice, demonstrate that impaired tmTNF/TNFR2, but not sTNF/TNFR1, promotes Th17 differentiation in vivo and in vitro. Under Th17-polarizing conditions, elevated IL-17 production by TNFR2-knockout CD4+ T cells was associated with increased STAT3 activity and decreased STAT5 activity. Increased IL-17 production in TNFR2-knockout T cells was prevented by adding exogenous IL-2. We conclude that CD4+ T cell–intrinsic tmTNF/TNFR2 promotes IL-2 production that inhibits the generation of Th17 cells in a Foxp3-independent manner. Moreover, under Th17-polarizing conditions, selective blockade of CD4+ T cell–intrinsic TNFR2 appears to be sufficient to promote Th17 differentiation.
Inhibition of B Lymphopoiesis by Adipocytes and IL-1–Producing Myeloid-Derived Suppressor Cells
Authors: Kennedy Domenick E. , Knight Katherine L. 
Published: August 2015

Abstract
B lymphopoiesis declines with age, and this decline correlates with increased adipose tissue in the bone marrow (BM). Also, adipocyte-derived factors are known to inhibit B lymphopoiesis. Using cocultures of mouse BM cells with OP9 stromal cells, we found that adipocyte-conditioned medium induces the generation of CD11b+Gr1+ myeloid cells, which inhibit B cell development in vitro. Adipocyte-conditioned medium–induced CD11b+Gr1+ cells express Arg1 (arginase) and Nos2 (inducible NO synthase) and suppress CD4+ T cell proliferation, indicating that these cells are myeloid-derived suppressor cells (MDSCs). Blocking arginase and inducible NO synthase did not restore B lymphopoiesis, indicating that inhibition is not mediated by these molecules. Transwell and conditioned-medium experiments showed that MDSCs inhibit B lymphopoiesis via soluble factors, and by cytokine array we identified IL-1 as an important factor. Addition of anti–IL-1 Abs restored B lymphopoiesis in BM cultures containing MDSCs, showing that MDSC inhibition of B lymphopoiesis is mediated by IL-1. By treating hematopoietic precursors with IL-1, we found that multipotent progenitors are targets of IL-1. This study uncovers a novel function for MDSCs to inhibit B lymphopoiesis through IL-1. We suggest that inflammaging contributes to a decline of B lymphopoiesis in aged individuals, and furthermore, that MDSCs and IL-1 provide therapeutic targets for restoration of B lymphopoiesis in aged and obese individuals.
Multiple Hepcidins in a Teleost Fish, Dicentrarchus labrax: Different Hepcidins for Different Roles
Authors: Neves João V. , Caldas Carolina , Vieira Inês , Ramos Miguel F. , Rodrigues Pedro N. S. 
Published: August 2015

Abstract
Teleost fish rely heavily on their innate immunity for an adequate response against pathogens and environmental challenges, with the production of antimicrobial peptides being one of their first lines of defense. Among those is hepcidin, a small cysteine-rich antimicrobial peptide that is also the key regulator of iron metabolism. Although most mammals possess a single hepcidin gene, with a dual role in both iron metabolism regulation and antimicrobial response, many teleost fish present multiple copies of hepcidin, most likely because of genome duplications and positive Darwinian selection, suggesting that different hepcidins may perform different functions. To study the roles of hepcidin in teleost fish, we have isolated and characterized several genes in the European sea bass (Dicentrarchus labrax) and evaluated variations in their expression levels in response to different experimental conditions. Although several hepcidin genes were found, after phylogenetic analysis they could be clustered in two groups: hamp1-like, with a single isoform similar to mammalian hepcidins, and hamp2-like, with several isoforms. Under experimental conditions, hamp1 was upregulated in response to iron overload and infection and downregulated during anemia and hypoxic conditions. Hamp2 did not respond to either iron overload or anemia but was highly upregulated during infection and hypoxia. In addition, Hamp2 synthetic peptides exhibited a clear antimicrobial activity against several bacterial strains in vitro. In conclusion, teleost fish that present two hepcidin types show a degree of subfunctionalization of its functions, with hamp1 more involved in the regulation of iron metabolism and hamp2 mostly performing an antimicrobial role.
Trends and variability in surface ozone over the United States
Authors: Strode Sarah A. , Rodriguez Jose M. , Logan Jennifer A. , Cooper Owen R. , Witte Jacquelyn C. , Lamsal Lok N. , Damon Megan , Van Aartsen Bruce , Steenrod Stephen D. , Strahan Susan E. 
Published: August 2015

AbstractWe investigate the observed trends and interannual variability in surface ozone over the United States using the Global Modeling Initiative chemical transport model. We discuss the roles of meteorology, emissions, and transport from the stratosphere in driving the interannual variability in different regions and seasons. We demonstrate that a hindcast simulation for 1991–2010 can reproduce much of the observed variability and the trends in summertime ozone, with correlation coefficients for seasonally and regionally averaged median ozone ranging from 0.46 to 0.89. Reproducing the interannual variability in winter and spring in the western United States may require higher‐resolution models to adequately represent stratosphere‐troposphere exchange. Hindcast simulations with fixed versus variable emissions show that changes in anthropogenic emissions drive the observed negative trends in monthly median ozone concentrations in the eastern United States during summer, as well as the observed reduction in the amplitude of the seasonal cycle. The simulation underestimates positive trends in the western United States during spring, but excluding the first 4 years of data removes many of the statistically significant trends in this region. The reduction in the slope of the ozone versus temperature relationship before and after major emission reductions is also well represented by the model. Our results indicate that a global model can reproduce many of the important features of the meteorologically induced ozone variability as well as the emission‐driven trends, lending confidence to model projections of future changes in regional surface ozone.
Seasonal variations, origin, and fate of settling diatoms in the Southern Ocean tracked by silicon isotope records in deep sediment traps
Authors: Closset Ivia , Cardinal Damien , Bray Stephen G. , Thil François , Djouraev Irina , Rigual‐Hernández Andrés S. , Trull Thomas W. 
Published: August 2015

AbstractThe Southern Ocean plays a pivotal role in the control of atmospheric CO2 levels, via both physical and biological sequestration processes. The biological carbon transfer to the ocean interior is tightly coupled to the availability of other elements, especially iron as a trace‐limiting nutrient and dissolved silicon as the mineral substrate that allows diatoms to dominate primary production. Importantly, variations in the silicon cycling are large but not well understood. Here we use δ30Si measurements to track seasonal flows of silica to the deep sea, as captured by sediment trap time series, for the three major zones (Antarctic, AZ; Polar Frontal, PFZ; and Sub‐Antarctic, SAZ) of the open Southern Ocean. Variations in the exported flux of biogenic silica (BSi) and its δ30Si composition reveal a range of insights, including that (i) the sinking rate of BSi exceeds 200 m d−1 in summer in the AZ yet decreases to very low values in winter that allow particles to remain in the water column through to the following spring, (ii) occasional vertical mixing events affect the δ30Si composition of exported BSi in both the SAZ and AZ, and (iii) the δ30Si signature of diatoms is well conserved through the water column despite strong BSi and particulate organic carbon (POC) attenuation at depth and is closely linked to the Si consumption in surface waters. With the strong coupling observed between BSi and POC fluxes in PFZ and AZ, these data provide new constraints for application to biogeochemical models of seasonal controls on production and export.
Lateral mixing across ice meltwater fronts of the Chukchi Sea shelf
Authors: Lu K. , Weingartner T. , Danielson S. , Winsor P. , Dobbins E. , Martini K. , Statscewich H. 
Published: August 2015

AbstractSummer and fall hydrographic sections in the northeastern Chukchi Sea frequently capture 5–20 m thick intrapycnocline lenses or horizontal plumes of warm, moderately salty summer Bering Sea Water flowing northward from Bering Strait. These features occur within the shallow (~20 m depth) pycnocline separating cold, dilute, surface meltwater from near‐freezing, salty, winter‐formed waters beneath the pycnocline. An idealized numerical model suggests that the features arise from eddies and meanders generated by instability of the surface front separating meltwater from Bering Sea Water. Warm Bering Sea Water is transported across the front and into the pycnocline by the cross‐frontal velocities associated with the instabilities. The accompanying lateral eddy heat fluxes may be important both in summer for promoting ice melt and in fall by delaying the onset of ice formation over portions of this shelf. Lateral heat flux magnitudes depend upon the stratification of the Bering Sea Water.
The 27 day solar rotational effect on mesospheric nighttime OH and O3 observations induced by geomagnetic activity
Authors: Fytterer T. , Santee M. L. , Sinnhuber M. , Wang S. 
Published: August 2015

AbstractObservations performed by the Earth Observing System Microwave Limb Sounder instrument on board the Aura satellite from 2004 to 2009 (2004 to 2014) were used to investigate the 27 day solar rotational cycle in mesospheric OH (O3) and the physical connection to geomagnetic activity. Data analysis was focused on nighttime measurements at geomagnetic latitudes connected to the outer radiation belts (55°N/S–75°N/S). The applied superposed epoch analysis reveals a distinct 27 day solar rotational signal in OH and O3 during winter in both hemispheres at altitudes >70 km. The OH response is positive and in‐phase with the respective geomagnetic activity signal, lasting for 1–2 days. In contrast, the O3 feedback is negative, delayed by 1 day, and is present up to 4 days afterward. Largest OH (O3) peaks are found at ~75 km, exceeding the 95% significance level and the measurement noise of <2% (<0.5%), while reaching variations of +14% (−7%) with respect to their corresponding background. OH at 75 km is observed to respond to particle precipitation only after a certain threshold of geomagnetic activity is exceeded, depending on the respective OH background. The relation between OH and O3 at 75 km in both hemispheres is found to be nonlinear. In particular, OH has a strong impact on O3 for relatively weak geomagnetic disturbances and accompanying small absolute OH variations (<0.04 ppb). In contrast, catalytic O3 depletion is seen to slow down for stronger geomagnetic variations and OH anomalies (0.04–0.13 ppb), revealing small variations around −0.11 ppm.
The night when the auroral and equatorial ionospheres converged
Authors: Martinis C. , Baumgardner J. , Mendillo M. , Wroten J. , Coster A. , Paxton L. 
Published: August 2015

AbstractAn all‐sky imaging system at the McDonald Observatory (30.67°N, 104.02°W, 40° magnetic latitude) showed dramatic ionospheric effects during a moderate geomagnetic storm on 1 June 2013. The auroral zone expanded, leading to the observation of a stable auroral red (SAR) arc. Airglow depletions associated with equatorial spread F (ESF) were also seen for the first time at such high magnetic latitude. Total electron content measurements from a Global Positioning System (GPS) receiver exhibited ionospheric irregularities typically associated with ESF. We explore why this moderate geomagnetic disturbance leads to such dramatic ionospheric perturbations at midlatitudes. A corotating interaction region‐like driver and a highly contracted plasmasphere caused the SAR arc to occur at L shell ~ 2.3. For ESF at L ~ 2.1, timing of the storm intensification, alignment of the sunset terminator with the central magnetic meridian, and sudden variations in the westward auroral electrojet all combined to trigger equatorial irregularities that reached altitudes of ~ 7000 km. The SAR arc and ESF signatures at the ionospheric foot points of inner magnetosphere L shells (L ~ 2) represent a dramatic convergence of pole to equator/equator to pole coupling at midlatitudes.
Ice export from the Laptev and East Siberian Sea derived from δ18O values
Authors: Rosén Per‐Olov , Andersson Per S , Alling Vanja , Mörth Carl‐Magnus , Björk Göran , Semiletov Igor , Porcelli Don 
Published: August 2015

AbstractIce export from the vast Arctic Siberian shelf is calculated using δ18O values and salinity data for water samples collected during the International Siberian Shelf Study between August and September 2008 (ISSS‐08). The samples represent a wide range of salinities and δ18O values due to river water inputs and sea ice removal. We estimate the fraction of water that has been removed as ice by interpreting observed δ18O values and salinities as a result of mixing between river water and sea water end‐members as well as to fractional ice removal. This method does not assume an ice end‐member of fixed composition, which is especially important when applied on samples with large differences in salinity. The results show that there is net transport of ice from both the Laptev and the Eastern Siberian Seas, and in total 3000 km3 of sea ice is exported from the shelf. The annual total export of ice from the entire region, calculated from the residence time of water on the shelf, is estimated to be 860 km3 yr−1. Thus, changes in ice production on the shelf may have great impact on sea ice export from the Arctic Ocean.
Effects of simulated spring thaw of permafrost from mineral cryosol on CO2 emissions and atmospheric CH4 uptake
Authors: Stackhouse Brandon T. , Vishnivetskaya Tatiana A. , Layton Alice , Chauhan Archana , Pfiffner Susan , Mykytczuk Nadia C. , Sanders Rebecca , Whyte Lyle G. , Hedin Lars , Saad Nabil , Myneni Satish , Onstott Tullis C. 
Published: August 2015

AbstractPrevious studies investigating organic‐rich tundra have reported that increasing biodegradation of Arctic tundra soil organic carbon (SOC) under warming climate regimes will cause increasing CO2 and CH4 emissions. Organic‐poor, mineral cryosols, which comprise 87% of Arctic tundra, are not as well characterized. This study examined biogeochemical processes of 1 m long intact mineral cryosol cores (1–6% SOC) collected in the Canadian high Arctic. Vertical profiles of gaseous and aqueous chemistry and microbial composition were related to surface CO2 and CH4 fluxes during a simulated spring/summer thaw under light versus dark and in situ versus water saturated treatments. CO2 fluxes attained 0.8 ± 0.4 mmol CO2 m−2 h−1 for in situ treatments, of which 85 ± 11% was produced by aerobic SOC oxidation, consistent with field observations and metagenomic analyses indicating aerobic heterotrophs were the dominant phylotypes. The Q10 values of CO2 emissions ranged from 2 to 4 over the course of thawing. CH4 degassing occurred during initial thaw; however, all cores were CH4 sinks at atmospheric concentration CH4. Atmospheric CH4 uptake rates ranged from −126 ± 77 to −207 ± 7 nmol CH4 m−2 h−1 with CH4 consumed between 0 and 35 cm depth. Metagenomic and gas chemistry analyses revealed that high‐affinity Type II methanotrophic sequence abundance and activity were highest between 0 and 35 cm depth. Microbial sulfate reduction dominated the anaerobic processes, outcompeting methanogenesis for H2 and acetate. Fluxes, microbial community composition, and biogeochemical rates indicate that mineral cryosols of Axel Heiberg Island act as net CO2 sources and atmospheric CH4 sinks during summertime thaw under both in situ and water saturated states.
Transition‐Metal‐Free Synthesis of Polysubstituted Cyclopropane Derivatives from N‐Tosylhydrazones and their Cytotoxic Activities
Authors: Lawson Marie , Bignon Jérôme , Brion Jean‐Daniel , Hamze Abdallah , Alami Mouad 
Published: August 2015

AbstractWe describe a general method for metal‐free cyclopropanation of different electron‐deficient olefins with N‐tosylhydrazones as a source of diazo compounds. This method works with N‐tosylhydrazones derived from acetophenones or benzophenones. This reaction is carried out in the presence of LiOtBu as a base to generate diazo species in situ. This method is compatible with various electron‐donating or electron‐withdrawing substituents and allows us to obtain a large library of functionalized tetrasubstituted cyclopropanes. Furthermore, we have used this method to synthesize isocombretastatine A4 analogues, which have submicromolar cytotoxicity against HCT‐116 cell lines.
[Cr(ddpd)2]3+: ein molekulares, wasserlösliches, hoch NIR‐lumineszentes Rubin‐Analogon
Authors: Otto Sven , Grabolle Markus , Förster Christoph , Kreitner Christoph , Resch‐Genger Ute , Heinze Katja 
Published: August 2015

AbstractIntensive, langlebige Lumineszenz von Metallkomplexen der ersten Übergangsmetallreihe ist sehr schwer zu erreichen. Wir stellen hier eine neue, auf rationaler Einstellung der beteiligten Energieniveaus basierende Strategie vor. Mithilfe des großen N‐Cr‐N Bisswinkels des dreizähnigen Liganden ddpd (N,N′‐Dimethyl‐N,N′‐dipyridin‐2‐ylpyridin‐2,6‐diamin) und seiner ausgeprägten σ‐Donoreigenschaften wird eine sehr große Ligandenfeldaufspaltung im Chrom(III)‐Komplex [Cr(ddpd)2]3+ erzielt. Dies hebt die Energie des desaktivierenden 4T2‐Zustands deutlich über die des emittierenden 2E‐Zustands. Das so vermiedene Rück‐ISC aus dem 2E‐ in den 4T2‐Zustand in diesem 3d‐Metallkomplex ermöglicht außerordentlich hohe Phosphoreszenzquantenausbeuten und Lebensdauern im nahen Infrarotbereich. Der Komplex [Cr(ddpd)2](BF4)3 ist gut wasserlöslich, sehr stabil gegenüber thermischen und photoinduzierten Substitutionsreaktionen und kann für Fluoreszenzintensitäts‐ und lebensdauer basierte O2‐Detektion im NIR verwendet werden.
Template Synthesis of Linear‐Chain Nanodiamonds Inside Carbon Nanotubes from Bridgehead‐Halogenated Diamantane Precursors
Authors: Nakanishi Yusuke , Omachi Haruka , Fokina Natalie A. , Schreiner Peter R. , Kitaura Ryo , Dahl Jeremy E. P. , Carlson Robert M. K. , Shinohara Hisanori 
Published: August 2015

AbstractA simple method for the synthesis of linear‐chain diamond‐like nanomaterials, so‐called diamantane polymers, is described. This synthetic approach is primarily based on a template reaction of dihalogen‐substituted diamantane precursors in the hollow cavities of carbon nanotubes. Under high vacuum and in the presence of Fe nanocatalyst particles, the dehalogenated radical intermediates spontaneously form linear polymer chains within the carbon nanotubes. Transmission electron microscopy reveals the formation of well‐aligned linear polymers. We expect that the present template‐based approach will enable the synthesis of a diverse range of linear‐chain polymers by choosing various precursor molecules. The present technique may offer a new strategy for the design and synthesis of one‐dimensional nanomaterials.
The Influence of Cu3(BTC)2 metal organic framework on the permeability and perm‐selectivity of PLLA‐MOF mixed matrix membranes
Authors: Kathuria Ajay , Al‐Ghamdi Saleh , Abiad Mohamad G. , Auras Rafael 
Published: August 2015

ABSTRACTPoly(l‐lactic acid) (PLLA) ‐ 20% (w/w) and Cu3(BTC)2 metal organic framework (MOF) based mixed matrix membranes (MMMs) were fabricated by a vertical corotating twin screw microcompounder followed by an injection molding process. Water vapor, CO2, O2, and selected aroma mass transfer properties of PLLA and PLLA MMMs were evaluated. The CO2/O2 perm‐selectivity of PLLA (αCO2/O2) MMMs increased from 7.6 to 10.3 with the incorporation of 20% Cu3(BTC)2 MOF. Gravimetric permeability studies of trans‐2‐hexenal performed at 23°C and 50% RH indicated that permeability coefficient of PLLA MMMs increased by around 60% as compared to regular PLLA film. However, no changes in mass transfer rates were observed for acetaldehyde. Furthermore, the thermal processing parameters as well as the presence of MOF did not show any significant effect on the molecular weight of the PLLA matrix nor on the crystalline structure of the Cu3(BTC)2 MOF, which was confirmed by both gel permeation chromatography and X‐ray diffraction studies. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42764.
Synthesis of a novel phosphonate flame retardant and its application in epoxy resins
Authors: Li Yang , Zheng Hongbing , Xu Miaojun , Li Bin , Lai Tao 
Published: August 2015

ABSTRACTA novel phosphonate flame retardant additive bis(2,6‐dimethyphenyl) phenylphosphonate (BDMPP) was synthesized from phenylphosphonic dichloride and 2,6‐dimethyl phenol, and its chemical structure was characterized by Fourier transform infrared (FTIR) spectroscopy, 1H and 31P nuclear magnetic resonance. The prepared BDMPP and curing agent m‐phenylenediamine were blended into epoxy resins (EP) to prepare flame retardant EP thermosets. The effect of BDMPP on fire retardancy and thermal degradation behavior of EP/BDMPP thermosets was investigated by limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter and thermalgravimetric analysis (TGA). The morphologies of char residues of the EP thermosets were investigated by scanning electron microscopy (SEM) and the water resistant properties of thermosets were evaluated by putting the samples into distilled water at 70°C for 168 h. The results demonstrated that the cured EP/14 wt % BDMPP composites with the phosphorus content of 1.11 wt % successfully passed UL‐94 V‐0 flammability rating and the LOI value was as high as 33.8%. The TGA results indicated that the introduction of BDMPP promoted EP matrix decomposed ahead of time compared with that of pure EP and led to a higher char yield at high temperature. The incorporation of BDMPP enhanced the mechanical properties and reduced the moisture absorption of EP thermosets. The morphological structures of char residue revealed that BDMPP benefited to the formation of a more compact and homogeneous char layer on the materials surface during burning, which prevented the heat transmission and diffusion, limit the production of combustible gases and then lead to the reduction of the heat release rate. After water resistance tests, EP/BDMPP thermosets still remained excellent flame retardancy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42765.