29 research outputs found
Jack Shepperd /
No full textRunning title: The life and adventures of Jack Shepperd.Published in 30 numbers.Paper covers identify publisher as Foster and Hextall; printer as Elliot.Obediah Throttle is the pseud. of an author writing a parody of William Harrison Ainsworth's Jack Sheppard.Caption title: The life and surprising adventures of Jack Shepperd."Printed and published by James Caton, at the Office, 268 Strand--Price and one penny" and "Printed and published by James Caton, at the Office, 11, Catharine-Street, Strand, in weekly numbers-price one penny" on inside margins of parts.Wolff, R.L. 19th cent. fiction,Mode of access: Internet
A 14 year climatology of Saharan dust emission mechanisms inferred from automatically tracked plumes
No full text The central and western Sahara (CWS) is the largest source of mineral aerosols during boreal summer, but observed ground‐based data are extremely scarce and typically distant from key source regions. Knowledge of dust emission mechanisms has therefore been mostly limited to short‐term observations from a point or model approximations. To address this deficiency, dust plumes from the CWS are classified according to emission mechanism for June, July and August of 2004‐2017 using an automated inference method which accurately tracks the timing, convective association and geometry of plumes observed with the Spinning Enhanced Visible and Infrared Imager (SEVIRI) aboard Meteosat Second Generation satellites. From these characteristics, plumes are classified as either low‐level jet or cold pool outflow events. The extensive data set is used to generate the largest available climatology of dust emission sources and Saharan emission mechanisms. Automated inference compares well with ground‐based measurements from the Fennec Campaign (76% accuracy) as well as with an entirely manual approach (88% accuracy). Cold pool activity accounts for 82% of total observed dust and 88% at the point of emission. Dust from cold pools evolves seasonally from hotspots around the Mali‐Niger‐Algeria border triple point towards the central Sahara to the northwest, while dust from low‐level jets is organised along the axis of the northeasterly Harmattan, and dominates emission within the Tidihelt Depression of central Algeria. The widespread importance of cold pool outflows in this research supports the findings of the Fennec Campaign, but low‐level jets remain highly significant in certain isolated hotspots. </p
Characterization of lymph node stromal cells during Treg-mediated tolerance
No full textSolid organs transplantation is therapy of choice for several human diseases. The success of this treatment is determined by the recipientÕs ability to prevent rejection. Rejection is currently controlled by immunosuppressive drugs, which unfortunately have side effects for patient quality of life as well as long-term graft survival. It is therefore important to better understand the molecular mechanisms underlying tolerance and rejection.
Regulatory T (Treg) cells are known to play an important role in suppressing immune responses, and have been demonstrated to be important for establishing allograft tolerance. To study Treg-mediated suppression we have generated a skin transplantation model in which the transfer of polyclonal Treg cells suppresses anti-Bm12 specific CD4 T cells (ABM cells) in a ratio dependent manner. Firstly, we characterized the migration pattern of both ABM and Treg cells to the skin graft and to the dLNs. High numbers of Treg cells delay the proliferation and reduce the IFN-g production of ABM cells in the LNs. The release of IFN-g by activated T cells was shown to influence the LN microenvironment comprised of stromal cells, which provide a structural environment for the homeostasis and differentiation of lymphocytes. Furthermore, T zone reticular cells (TRCs) were shown to provide survival factors and negatively regulate activated T cells during strong inflammatory responses. We showed that the presence of Treg cells was modifying the TRC activity during the establishment of tolerance. TRCs isolated from LNs of mice tolerating the graft exhibited enhanced transcription of the chemokines CCL19 and CCL21, the adhesion molecules ICAM-1 and VCAM-1 and the cytokines TSLP and IL-7 compared to TRCs isolated from mice transferred with ABM cells only. In our analysis we focused on the survival factor IL-7 and its role in activation. We found that IL-7 signaling in activated Treg cells leads to further upregulation of the IL-2Ra-chain CD25 and enhances Treg suppressive capacity in vitro.
In summary, Treg cells suppress activation and IFN-g release by effector T cells and promote TRC release of IL-7. We hypothesize that TRC derived IL-7 may be required to maintain high numbers of Treg cells in the LNs and to prevent skin graft alloresponses. In addition, IL-7 might sensitize Treg cells and facilitate their recognition of IL-2, leading to Treg cell expansion and better suppression of effector T cell responses
A new index used to characterise the extent of Antarctic marine coastal winds in climate projections
No full textAntarctic marine coastal near-surface winds play a key role in Southern Ocean circulation. Using the ERA5 reanalysis dataset, this paper develops directional wind constancy as a tool for identifying key features in these winds and their relationship with the mid-latitude westerly jet. In particular, the Antarctic coastal wind boundary (ACWB), defined as the minimum offshore directional constancy boundary, is shown to be a useful way to define the marine near-coastal region where the Antarctic topography plays an important role in influencing the wind direction. We show that, while the ACWB is linked to large-scale modes of atmospheric circulation through its close association with variability in the mid-latitude westerly jet, it also highlights key regions where topographically-influenced, meridional flows are dominant. These meridional flows are not identified in current regional climate indices. Future changes in the ACWB are examined using CMIP6 projections for a high emissions scenario. This indicates that by the end of this century the ACWB is projected to shift poleward by about 60 km, less than the 130 km shift in the mid-latitude westerly jet, indicating a reduction in the extent of the circumpolar trough.</p
An extensive investigation of the ability of the ICOLMDZ model to simulate a katabatic wind event in Antarctica
No full textKatabatic winds are a key feature of the climate of Antarctica, but despite decades of extensive studies, substantial biases remain in their representation in atmospheric models. However, it is often difficult to identify the origin of those biases amongst the model resolution, physical content, and large-scale forcings aspects. This study conducts an extensive investigation of the ability of the ICOLMDZ atmospheric model to simulate Antarctic katabatic winds by disentangling uncertainties associated with parameter calibration, from those associated with horizontal resolution as well as structural deficiencies in the model with a particular attention given to turbulent diffusion. We carefully select a katabatic-driven wind event in clear-sky conditions in Adélie Land, and perform perturbed parameter experiments at three different horizontal resolutions (10, 20 and 40 km). ICOLMDZ is able to reproduce wind observations, but the parametric uncertainty remains large and structural differences not associated with parameter calibration nor horizontal resolution are found for turbulence and near-surface temperature. A parametric analysis reveals that the most critical parameter controlling the magnitude of near-surface winds is roughness length, whereas near-surface temperatures are mainly controlled by snow near-infrared albedo. Sensitivity to horizontal resolution reveals that the 40 km configuration compares least favourably with the observations, and that the 10 and 20 km ensembles cannot be distinguished due to a too wide parametric uncertainty. We then discuss three aspects of katabatic winds modeling that we deem critical but underappreciated: the parameterization of roughness length over snow, oscillations in katabatic flows, and the representation of subgrid-scale orographic drag. This study underlines in particular the need for a more physical parameterization of roughness length to correctly represent near-surface wind along the slopes of Antarctica.</p
Influence of Orography Upon Summertime Low-Level Jet Dust Emission in the Central and Western Sahara
No full textLow-level jets (LLJs) drive frequent emission of mineral dust in the central and western Sahara in boreal summer. A major hotspot for this process is central Algeria, northern Mali and Mauritania, through which blow the dry near-surface northeasterly Harmattan winds, with a peak in dust emission around the low-lying Tidihelt region. North African orography is thought to contribute to the strength of the LLJ over the Bodele dust source in Chad, but its influence on erosivity over summertime source regions remains unquantified. In this paper, the contribution of central Saharan orography to the strength of Harmattan LLJs and associated dust emission frequency is tested. An idealized simulation with flattened Hoggar mountains is compared with a control using the Met Office Unified Model at 12 km horizontal resolution. In the absence of the Hoggar mountains, dust emission frequency estimated using an empirical relationship with surface wind speeds is found to decline across the entire northeasterly “LLJ alley,” including by 31% in the Tidihelt where composited jet surface winds drop from 9.0 to 7.3 m s−1 under a more easterly regime. The mountains are linked to a low-level leeward geopotential height perturbation, with a northern limb reinforcing northeasterlies through the Tidihelt. Dome-shaped elevated heating situated over the Hoggar mountains explains the difference between the simulated wind fields in the two experiments. These findings suggest that central Saharan orography plays an important role in sustaining erosive dusty conditions during boreal summer
Sufentanil intratecal associado ou não a bupivacaína para analgesia de parto
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-graduação em Ciências MédicasIntrodução: A analgesia de parto desperta interesse desde o século XVIII, tempo que ainda oferecia muita resistência às técnicas disponíveis na época. Com a evolução do conhecimento e desenvolvimento de novos anestésicos e analgésicos, permanece sempre atual o interesse pelas mais diversas técnicas e medicamentos
Structural Diversity of Monoclonal CD4 Antibodies and Their Capacity to Block the HIV GP120/CD4 Interaction
No full textNovel fusion protein-expressing lentiviral vectors ameliorate collagen induced arthritis
No full textCollagen induced arthritis (CIA) is a mouse model of autoimmunity that
closely resembles human rheumatoid arthritis (RA), a debilitating disease with no cure. This study has been undertaken to generate antigen-specific tolerance to an
autoantigen implicated in RA and immunodominant in animal models. Gene therapy protocols for RA that have gone to clinical trial have been designed to drive
expression of therapeutic molecules at the site of inflammation, but not to modulate
the immune response to key autoantigens.
This study has shown that lentiviral vectors (lvv) expressing fusion proteins
(FP-lvv) confer antigen-specific tolerance in CIA. Fusion proteins comprised of an endosomal-targeting domain coupled to the immunodominant CII259-273 peptide and
an eGFP tag, were expressed in APCs. Confocal microscopy revealed substantial
colocalisation with endosomes and lysosomes. Expression of the fusion proteins in
APCs resulted in MHCII-presentation of the immunodominant CII259-273 peptide to
CII259-273-reactive CD4+ T cell hybridomas. Furthermore, co-transduction with a lvv
expressing the enzyme lysyl-hydroxylase 3 enhanced glycosylation of the expressed
CII construct.
Administering mice iv with FP-lvv one month prior to disease induction
reduces by half the arthritic score during the first two weeks of clinical symptoms in
CIA, providing partial but significant protection. The use of suitable controls showed
that this effect is antigen-specific and measurements of α-CII IgG show a
significantly lower titre in treated animals.
This study provides evidence that lvv-mediated MHCII-presentation can be tolerogenic and hence, this approach could form an important part of future treatments for autoimmune diseases
The effect of two novel C-type lectins, Ba100 and Ba25, isolated from the venom of the puff adder, Bitis arietans on T lymphocyte proliferative responses
No full textIncludes abstract.
Includes bibliographical references (p. 233-318)
