The RONOCO (ROle of Nighttime chemistry in controlling the Oxidising Capacity of the AtmOsphere) aircraft campaign during July 2010 and January 2011 made observations of OH, HO.sub.2, NO.sub.3, ...N.sub.2 O.sub.5 and a number of supporting measurements at night over the UK, and reflects the first simultaneous airborne measurements of these species. We compare the observed concentrations of these short-lived species with those calculated by a box model constrained by the concentrations of the longer lived species using a detailed chemical scheme. OH concentrations were below the limit of detection, consistent with model predictions. The model systematically underpredicts HO.sub.2 by ~200% and overpredicts NO.sub.3 and N.sub.2 O.sub.5 by around 80 and 50%, respectively. Cycling between NO.sub.3 and N.sub.2 O.sub.5 is fast and thus we define the NO.sub.3x (NO.sub.3x =NO.sub.3 +N.sub.2 O.sub.5) family. Production of NO.sub.3x is overwhelmingly dominated by the reaction of NO.sub.2 with O.sub.3, whereas its loss is dominated by aerosol uptake of N.sub.2 O.sub.5, with NO.sub.3 +VOCs (volatile organic compounds) and NO.sub.3 +RO.sub.2 playing smaller roles. The production of HO.sub.x and RO.sub.x radicals is mainly due to the reaction of NO.sub.3 with VOCs. The loss of these radicals occurs through a combination of HO.sub.2 +RO.sub.2 reactions, heterogeneous processes and production of HNO.sub.3 from OH+NO.sub.2, with radical propagation primarily achieved through reactions of NO.sub.3 with peroxy radicals. Thus NO.sub.3 at night plays a similar role to both OH and NO during the day in that it both initiates RO.sub.x radical production and acts to propagate the tropospheric oxidation chain. Model sensitivity to the N.sub.2 O.sub.5 aerosol uptake coefficient (γ.sub.N.sub.2 O.sub.5) is discussed and we find that a value of γ.sub.N.sub.2 O.sub.5 =0.05 improves model simulations for NO.sub.3 and N.sub.2 O.sub.5, but that these improvements are at the expense of model success for HO.sub.2 . Improvements to model simulations for HO.sub.2, NO.sub.3 and N.sub.2 O.sub.5 can be realised simultaneously on inclusion of additional unsaturated volatile organic compounds, however the nature of these compounds is extremely uncertain.
Here we explore how incorporation of the omega-3 fatty acid docosahexaenoic acid (DHA) into murine leukemia cells (T27A) may alter membrane structure and function. When cells were cultured in ...DHA-supplemented medium, DHA incorporated rapidly and preferentially into phosphatidyl-ethanolamine (PE), with lesser and slower incorporation into phosphatidylcholine (PC). DHA at low concentrations preferred PE over neutral lipids, but in DHA excess accumulation in neutral lipids outstripped that of phospholipids. High DHA levels reduced cell growth in the apparent absence of lipid peroxidation. To study the importance of DHA's phospholipid class, cells were fused with lipid vesicles of either 18:0, 22:6 PE or 18:0, 22:6 PC. DHA-containing PC vesicles produced a dose-dependent decrease in cell viability, whereas PE-containing vesicles had little effect although they appeared more fusogenic. These results provoke the interesting speculation that T27A cells can safely accumulate DHA in PE, but are vulnerable if excessive DHA is incorporated into PC.
To present a case of maternal morbidity encountered in a cervical heterotopic pregnancy after successful potassium chloride (KCl) injection for transvaginal multifetal pregnancy reduction.
Case ...report.
Tertiary referral care center.
A woman with heterotopic twin gestation after IVF.
Diagnosis of a viable cervical heterotopic pregnancy was made at 6 weeks by ultrasound. A transvaginal reduction by KCl injection of the cervical pregnancy was performed under sonographic guidance.
Maternal morbidity and mortality.
Although contents of the gestational sac within the cervix resolved, the trophoblastic tissue increased in both size and vascularity. The patient continued to have self-limited vaginal bleeding throughout the pregnancy. However, at 31 weeks, she had an acute hemorrhage, resulting in an emergency cesarean hysterectomy secondary to profuse bleeding from retained cervical trophoblastic tissue.
Although KCl transvaginal multifetal pregnancy reduction might successfully terminate a cervical heterotopic pregnancy, the ongoing pregnancy might be complicated by persistence and even enlargement of remaining trophoblastic tissue, leading to obstetric hemorrhage.
T cell activation is initiated by recognition of antigenic peptide presented in complex with MHC molecules on the surface of APCs. The mechanism by which this recognition occurs is still unclear, and ...many models exist in the literature. CD4 T cells have been shown to respond to soluble oligomers of activating class II MHC-peptide complexes, but not to soluble monomers. In determining the reactivity of CD8 T cells to soluble activating class I MHC-peptide complexes, a complicating phenomenon had been observed whereby peptide from soluble complexes was loaded onto cell surface MHCs on the T cells and re-presented to other T cells, clouding the true valency requirement for activation. This study uses soluble allogeneic class I MHC-peptide monomers and oligomers to stimulate murine CD8 T cells without the possible complication of peptide re-presentation. The results show that MHC class I monomers bind to, but do not activate, CD8 T cells whether the cells are in solution or adhered to a surface. Monomeric MHC class I binding can antagonize the stimulation triggered by soluble oligomers, a phenomenon also observed for CD4 T cells. Dimeric engagement is necessary and sufficient to stimulate downstream activation processes including TCR down-regulation, Zap70 phosphorylation, and CD25 and CD69 up-regulation, even in T cells that do not express the MHC coreceptor CD8. Thus, the valency dependence of the response of CD8 T cells to soluble MHC-peptide reagents is the same as previously observed for CD4 T cells.
We present the final results obtained by the MACRO experiment in the search for GUT magnetic monopoles in the penetrating cosmic radiation, for the range \(4\times 10^{-5}< \beta < 1\). Several ...searches with all the MACRO sub-detectors (i.e. scintillation counters, limited streamer tubes and nuclear track detectors) were performed, both in stand alone and combined ways. No candidates were detected and a 90% Confidence Level (C.L.) upper limit to the local magnetic monopole flux was set at the level of \(1.4\times 10^{-16}\) cm-2 s-1 sr-1. This result is the first experimental limit obtained in direct searches which is well below the Parker bound in the whole \(\beta\) range in which GUT magnetic monopoles are expected.
This timely exploration and re-assessment of Canada's approach to strategic affairs offers a diverse set of nuanced, sometimes controversial, and always insightful perspectives on the most pressing ...security challenges that Canada currently faces.
The K2K long-baseline neutrino oscillation experiment uses a Scintillating Fiber Detector (SciFi) to reconstruct charged particles produced in neutrino interactions in the near detector. We describe ...the track reconstruction algorithm and the performance of the SciFi after 3 years of operation.
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