Biomass burning (BB) is a large source of primary and secondary organic aerosols (POA and SOA). This study addresses the physical and chemical evolution of BB organic aerosols. Firstly, the evolution ...and lifetime of BB POA and SOA signatures observed with the Aerodyne Aerosol Mass Spectrometer are investigated, focusing on measurements at high-latitudes acquired during the 2008 NASA ARCTAS mission, in comparison to data from other field studies and from laboratory aging experiments. The parameter f60, the ratio of the integrated signal at m/z 60 to the total signal in the organic component mass spectrum, is used as a marker to study the rate of oxidation and fate of the BB POA. A background level of f60~0.3% ± 0.06% for SOA-dominated ambient OA is shown to be an appropriate background level for this tracer. Using also f44 as a tracer for SOA and aged POA and a surrogate of organic O:C, a novel graphical method is presented to characterise the aging of BB plumes. Similar trends of decreasing f60 and increasing f44 with aging are observed in most field and lab studies. At least some very aged BB plumes retain a clear f60 signature. A statistically significant difference in f60 between highly-oxygenated OA of BB and non-BB origin is observed using this tracer, consistent with a substantial contribution of BBOA to the springtime Arctic aerosol burden in 2008. Secondly, a summary is presented of results on the net enhancement of OA with aging of BB plumes, which shows large variability. The estimates of net OA gain range from ΔOA/ΔCO(mass) = −0.01 to ~0.05, with a mean ΔOA/POA ~19%. With these ratios and global inventories of BB CO and POA a global net OA source due to aging of BB plumes of ~8 ± 7 Tg OA yr−1 is estimated, of the order of 5 % of recent total OA source estimates. Further field data following BB plume advection should be a focus of future research in order to better constrain this potentially important contribution to the OA burden.
To study the ability of a stabilizing reagent to prevent cellular DNA contamination of cell-free DNA (cfDNA) in plasma during whole blood sample storage and shipping.
Samples were drawn from healthy ...donors into K3EDTA and Cell-Free DNA BCTs (BCT) and stored at room temperature (RT). Aliquots were removed at specified time points and cfDNA was purified from the plasma. A Droplet Digital PCR (ddPCR) assay that amplifies a short β-actin gene fragment (136bp) was used to measure the total plasma cfDNA (pDNA) concentration while a longer β-actin fragment (420bp) was used to quantify genomic DNA (gDNA). In a follow-up experiment, blood samples drawn into the same types of tubes were shipped round trip by overnight air before cfDNA was isolated and analyzed.
Blood stored in K3EDTA tubes at RT showed increases in pDNA and gDNA concentrations over time. However, both pDNA and gDNA levels remained stable in BCT for at least seven days. On day 14, there was a 4.5-fold increase in pDNA in BCT as compared to >200-fold increase in K3EDTA tubes. Likewise, gDNA increased <2-fold on day 14 in BCT as opposed to a 456-fold increase in K3EDTA tubes. Similar results were observed after samples were shipped.
Cell-Free DNA BCTs prevent gDNA contamination that may occur due to nucleated cell disruption during sample storage and shipping. This novel blood collection tube provides a method for obtaining stable cfDNA samples for rare target detection and accurate analysis while mitigating the threat of gDNA contamination.
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•We tested post-phlebotomy stressors in traditional and specialized collection tubes.•Samples were stored at room temperature for fourteen days or shipped for 48h.•A long and a short fragment of the same gene modeled genomic and cell free DNA.•Targets were assayed with a next generation PCR method, Droplet Digital PCR.•Cell-Free DNA BCT prevented changes while K3EDTA showed dramatic increases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Globally, preterm birth remains the leading cause of death in children younger than 5 years old. Spontaneous preterm birth is comprised of two events that may or may not occur simultaneously: preterm ...labor and preterm prelabor rupture of membranes (PPROM). To further explore the concept that spontaneous preterm birth can result from the initializing of two separate but overlapping pathological events, we compared fetal membrane tissue from preterm labor deliveries to fetal tissue from preterm labor with PPROM deliveries. We hypothesized that the fetal membrane tissue from preterm labor with PPROM cases will have an RNA-seq profile divergent from the fetal membrane tissue from preterm labor controls.
Chorioamnion, separated into amnion and chorion, was collected from eight gestationally age-matched cases and controls within 15 min of birth, and analyzed using RNA sequencing. Pathway enrichment analyses and functional annotations of differentially expressed genes were performed using KEGG and Gene Ontogeny Pathway enrichment analyses.
A total of 1466 genes were differentially expressed in the amnion, and 484 genes were differentially expressed in the chorion (log2 fold change > 1, FDR < 0.05) in cases (preterm labor with PPROM), versus controls (preterm labor only). In the amnion, the most significantly enriched (FDR < 0.01) KEGG pathway among down-regulated genes was the extracellular matrix receptor interaction pathway. Seven of the most significantly enriched pathways were comprised of multiple genes from the COL family, including COL1A, COL3A1, COL4A4, and COL4A6. In the chorion, the most significantly enriched KEGG pathways in up-regulated genes were chemokine, NOD receptor, Toll-like receptor, and cytokine-cytokine receptor signaling pathways. Similarly, KEGG pathway enrichment analysis for up-regulated genes in the amnion included three inflammatory pathways: cytokine-cytokine interaction, TNF signaling and the CXCL family. Six genes were significantly up regulated in chorionic tissue discriminated between cases (preterm labor with PPROM) and controls (preterm labor only) including GBP5, CXCL9, ALPL, S100A8, CASP5 and MMP25.
In our study, transcriptome analysis of preterm fetal membranes revealed distinct differentially expressed genes for PPROM, separate from preterm labor. This study is the first to report transcriptome data that reflects the individual pathophysiology of amnion and chorion tissue from PPROM deliveries.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Numerous nitramine bridged compounds which show promising combinations of properties have already been identified in the area of energetic materials. In this work, four new nitrazapropane bridged ...tetrazoles, as well as four new trinitrazaheptane tetrazoles and three oxapropane bridged tetrazoles were synthesized and fully characterized. These new compounds can all be synthesized by a simple, one‐step synthesis using Finkelstein conditions. All of these new energetic materials were characterized using NMR spectroscopy, single crystal X‐ray diffraction, vibrational analysis and elemental analysis. The thermal behaviour of these compounds was studied by differential thermal analysis (DTA) and partly by thermogravimetric analysis (TGA). The BAM standard method was used to determine the sensitivities towards impact (IS) and friction (FS). The enthalpies of formation were calculated at the CBS‐4M level, and the energetic performances were calculated using the EXPLO5 (V6.06.01) computer code. The properties of the new compounds were compared to each other as well as to the known energetic material RDX. Moreover, the iron(II) and copper(II) perchlorate complexes with 1,3‐bis‐1,1‐tetrazolylnitrazapropane as ligand were prepared and investigated.
Several new nitramine‐ and oxa‐bridged bis‐tetrazolyl energetic materials were synthesized and fully characterized. The thermal behavior of all compounds was studied and their sensitivities towards impact (IS) and friction (FS) determined. Energetic properties, were calculated using the EXPLO5 (V6.06.01) computer code. In particular, 1,3‐bis‐2,2’‐nitrotetrazolylnitrazapropane and 1,7‐bis‐2,2’‐tetrazolyltrinitrazaheptane show promising properties for use as RDX replacements.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
During its Run 2 (2015–2018), the Large Hadron Collider (LHC) operated at almost twice higher energy, and provided Pb-Pb collisions with an order of magnitude higher luminosity, than in the previous ...Run 1. In consequence, the power of the secondary beams emitted from the interaction points by the bound-free pair production (BFPP) process increased by a factor∼20, while the propensity of the bending magnets to quench increased with the higher magnetic field. This beam power is about 35 times greater than that contained in the luminosity debris from hadronic interactions and is focused on specific locations that fall naturally inside superconducting magnets. The risk of quenching these magnets has long been recognized as severe and there are operational limitations due to the dynamic heat load that must be evacuated by the cryogenic system. High-luminosity operation was nevertheless possible thanks to orbit bumps that were introduced in the dispersion suppressors around the ATLAS and CMS experiments to prevent quenches by displacing and spreading out these beam losses. Further, in 2015, the BFPP beams were manipulated to induce a controlled quench, thus providing the first direct measurement of the steady-state quench level of an LHC dipole magnet. The same experiment demonstrated the need for new collimators that are being installed around the ALICE experiment to intercept the secondary beams in the future. This paper discusses the experience with BFPP at luminosities very close to the future High Luminosity LHC (HL-LHC) target, gives results on the risk reduction by orbit bumps and presents a detailed analysis of the controlled quench experiment.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM, UPUK
Levitated nanospheres in optical cavities open a novel route to study many-body systems out of solution and highly isolated from the environment. We show that properly tuned optical parameters allow ...for the study of the nonequilibrium dynamics of composite nanoparticles with nonisotropic optical friction. We find optically induced ordering and nematic transitions with nonequilibrium analogs to liquid crystal phases for ensembles of dimers.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Summary
The insertion of an epidural catheter for labour analgesia may be challenging. This observational study compared pressures during insertion of an epidural catheter in pregnant (n = 35) and ...non‐pregnant (n = 10) women, using an acoustic device for locating the epidural space that also records and stores pressure data during the procedure. In both groups, we compared the maximum pressure just before loss of resistance, the pressure in the epidural space and the pressure in the inserted epidural catheter. Maximum pressure just before loss of resistance in the pregnant women was significantly lower compared with the non‐pregnant women. Pressures in the epidural space and with the disposable tubing connected to the inserted epidural catheter were greater in pregnant women than in non‐pregnant women. The results support the hypothesis that physiological changes in the third trimester of pregnancy are the reason why epidural catheters are more difficult to insert in women in labour.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
Two 6 t beam dumps, made of a graphite core encapsulated in
a stainless steel vessel, are used to absorb the energy of the two
Large Hadron Collider (LHC) intense proton beams during ...operation of
the accelerator. Operational issues started to appear in 2015 during
LHC Run 2 (2014–2018) as a consequence of the progressive increase
of the LHC beam kinetic energy, necessitating technical
interventions in the highly radioactive areas around the
dumps. Nitrogen gas leaks appeared after highly energetic beam
impacts and instrumentation measurements indicated an initially
unforeseen movement of the dumps. A computer modelling analysis
campaign was launched to understand the origin of these issues,
including both Monte Carlo simulations to model the proton beam
interaction as well as advanced thermo-mechanical analyses. The main
findings were that the amount of instantaneous energy deposited in
the dump vessel leads to a strong dynamic response of the whole dump
and high accelerations (above 200 g). Based on these findings, an
upgraded design, including a new support system and beam windows,
was implemented to ensure the dumps' compatibility with the more
intense beams foreseen during LHC Run 3 (2022–2025) of 539 MJ per
beam. In this paper an integral overview of the operational
behaviour of the dumps and the upgraded configurations are
discussed.
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