1,674 research outputs found
John Bennet Herff
No full textPhotograph shows studio portrait of John B. Herff, as a boy, wearing a lace collar.Photographer's imprint on back of original:""D.P. Barr, Artistic Photographer, San Antonio, Texas." Herff was the son of Eda Kampmann Herff and Dr. John Herff
Wenceslao Martinez and son, Bartolo Martinez, 1880s
No full textPhotograph shows three-quarter length studio portrait of Wenceslao Martinez and son, Bartolo Martinez. They are holding felt hats.Photographer's stamp on back:''"D. P. Barr, Photographer, San Antonio, Texas"
Complexities associated with expression of Epstein-Barr virus (EBV) lytic origins of DNA replication.
No full textEBV has two lytic origins (oriLyt) of DNA replication lying at divergent sites on the viral genome within a duplicated sequence (DS). The latter contains potential hairpin loops, ‘hinge’ elements and the promoters for transcripts from viral genes BHLF1 and LF3. These genes themselves consist largely of 125 and 102 bp repetitive sequences, respectively, and encode basic proteins. We have examined these genomic regions in detail in attempts to understand why lytic replication—necessary for virus survival—is so inefficient, and to identify controlling elements. Our studies uncovered a diverse family of promoters (P) for BHLF1 and LF3, only one pair of which (P1) proved sensitive to chemical inducing agents. The others (P2–P3/4), abutting the replication ‘core’ origin elements in DS and extending into 50-unique sequences, may play roles in the maintenance of viral latency. We further identified a family of overlapping small complementary-strand RNAs that transverse the replication ‘core’ origin elements in a manner suggesting a role for them as ‘antisense’ species and/or DNA replication primers. Our data are discussed in terms of alternative lytic replication models. We suggest our findings might prove useful in seeking better control over viral lytic replication and devising strategies for therapy
Epstein-Barr virus latent proteins regulate expression of the anti-apoptotic cellular bfl-1 gene
No full textThe ubiquitous and oncogenic human herpes-virus Epstem-Barr virus (EB V) establishes a latent infection and promotes the long-term survival of the infected host cell by targeting the molecular machinery that controls cell fate decisions, including apoptosis, proliferation and differentiation. These host-virus interactions are likely to play a crucial role in the development of EBV-associated malignancies such, as Burkitt’s lymphoma, Hodgkin’s disease, nasopharyngeal carcinoma and tumours in lmmunosuppressed individuals. It has previously been shown in our laboratory that two EBV latent proteins, latent membrane protein 1 (LMP1) and EBV nuclear antigen 2 (EBNA2), which are major effectors of cellular phenotypic change, can independently regulate expression of the cellular bfl-1 gene Bfl-1 is an anti-apoptotic protein of the Bcl-2 family, whose preferential expression in hematopoietic and endothelial cells is controlled by inflammatory stimuli. In this study, it is reported that LMP1 and EBNA2 regulate bfl-1 activity through interactions with components of the NF-kB and Notch signalling pathways respectively NF-kB composed of p65 sub-units trans-activated the bfl-1 promoter m the EBV-negative cell line DG75, and an NF-icB-like binding site at position -52 to -43 relative to the transcription start site was essential for this effect. An RBP-Jk/CBF1 mutant blocked EBNA2-mediated trans-activation of bfl-1 in DG75 cells, indicating an important role for this DNA-binding protein in bfl-1 trans-activation by EBNA2. Although RBP-Jk/CBFI is also essential for signalling by the cellular equivalent of EBNA2, mtra-cellular Notch (NotchIC), this protein was not found to trans-activate the bfl-1 promoter. Both EBNA2 and LMP1 are expressed in EBVmfected cell lines, and EBNA2 is responsible for induction of LMP1 Blocking of either EBNA2- or LMP1-mediated signalling in EBV-mfected cell lines did not dramatically affect the level of bfl-1 promoter activity. However, when both EBNA2 and LMP1 signalling were blocked simultaneously, a significant decrease in the level of bfl-1 activity was observed. These data indicate a role for both EBNA2 and LMP1 in the regulation of the promoter for the bfl-1 gene m the context of the EBV-infected cell. These findings are relevant to our understanding of EBV persistence in the infected host, and its role in malignant disease
New exact coherent states in channel flow
No full textThree spatially periodic travelling wave exact coherent states are presented for channel flow. Two of the flows, which are asymmetric with respect to the channel centreplane, are derived by homotopy from solutions for channel flow subject to a spanwise rotation investigated by [1]. The third flow satisfies a half-turn rotational symmetry about a point on the channel centreplane, and turns out to be the flow from which one of the asymmetric flows bifurcates in a symmetry breaking bifurcation. One of the asymmetric flows is found to substantially reduce the value of the lowest Reynolds number at which exact solutions are known to exist down to 665
Murine Model System for EBV-related Diseases
No full textEpstein-Barr Virus (EBV) is involved in several human malignancies via its latent gene products, which interact with cellular proteins and mimic discrete functions of cellular signalling pathways. Enigmatically, more than 90% of the human population carries this human tumour virus but virus-associated tumours are relatively rare.
Most studies on EBV have been carried out in vitro and ex vivo on EBV-transformed human B cells or on human biopsies. Established in vivo model systems do not reflect the main aspects of EBV-associated diseases in humans. This limited tool set is the result of EBV’s inability to infect cells of non-human origin, which lack the surface receptor for EBV.
My PhD work aimed at engineering a transgenic mouse, which carries a conditionally inactivated EBV genome.
This study took advantage of the well-established techniques of mouse genetics in order to stably integrate the entire EBV genome into the murine genome. This approach would not only overcome the inability of EBV to infect animal cells but it would also permit to study the complete virus in an immunocompetent and easy-to-handle living organism.
I undertook two routes to establish a transgenic mouse with the complete EBV genome inserted. One route was based on the site-specific integration into the hprt locus of murine embryonic stem cells. The other route engaged pronucleus microinjection of the EBV DNA into fertilized murine oocytes. In addition, the EBV genome was genetically manipulated prior to its introduction into murine cells. On the basis of the E.coli cloned EBV strain B95.8, I constructed a novel EBV mutant with unique features. This EBV targeting construct (InvTarg) allows conditional expression of EBV’s latent genes via a Cre/loxP system. Such approach prevents potentially adverse effects of EBV’s latent genes on embryonic development but allows their expression in almost any chosen cellular compartment for which specific Cre-expressing mice are available.
The InvTarg recombinant EBV genome is 185 kb in size, based on a bacterial replicon, and therefore belonging to Bacterial Artificial Chromosomes (BACs). Two genetically modified and inversely oriented loxP sites were introduced in E.coli cells at the predetermined sites of the InvTarg, and the bracketed segment was inverted by Cre recombinase, disrupting transcription of almost all viral latent genes. In transgenic animals this inversion can be reverted and the latent genes can be re-activated at will by cross-breeding with Cre-expressing mouse (re-inversion). The ability of Cre to invert the big fragment was verified in infection experiments with human primary B cells. As expected, the ‘inverted’ EBV construct, such as InvTarg, failed to transform primary B cells, when the viral latent genes were not expressed. Despite sustained efforts, both gene delivery techniques did not lead to a transgenic mouse with the entire EBV genome inserted, but resulted in the integration of only subgenomic segments of the InvTarg recombinant EBV DNA.
A number of technical problems were identified during this work, indicating more specific direction for further research. On the basis of the experience gained here, the project of an EBV transgenic mouse can be carried on. In addition, the InvTarg maxi-EBV conditional vector might be employed in other experimental conditions, like different cell types or distinct stages of cell differentiation, for studies on latent EBV genes
Scouts & Guides - Latvians WWII
No full textA detailed description (including locations, dates and Troup No.'s) where Boy Scouts and Girl Guides were present during WWII and Post WWII (including Troup numbers)6.0 Documents, 3.0 The War Years, 3.1.9 D.P. Camps, 10.0 Life of Latvian Children, 10.1.4 Boy Scouts and Girl Guide
Author Correction:A 41,500 year-old decorated ivory pendant from Stajnia Cave (Poland)
No full textCorrection to: Scientific Reports https://doi.org/10.1038/s41598-021-01221-6, published online 25 November 2021The original version of this Article contained errors in the author list where Marjolein D. Bosch was omitted from the author list, and Mikołaj Urbanowski was incorrectly listed as an author of the original Article, and has subsequently been removed.The Author contributions section now reads:“S.T. W.N. and A.N. conceived the project; S.T., W.N., A.P., M.B., S.C., M.D., H.F., A.M., M.D. B., D.P., M.P.R., C.M.R., V.S-M., G.M.S., P.S., M.S., K.S., A.V., F.W., H.W., A.W., M.Z., S.B., A.N., J-J. H., performed research; S.T., A.P., W.N., M.B., M.D.B., S.C., M.D., H.F., A.M., D.P., M.P.R., C.M.R., V.S-M., G.M.S., P.S., M.S., K.S., A.V., F.W., H.W., A.W., M.Z., S.B., A.N., J-J. H. analysed all archaeological data; S.T. and A.P. wrote the paper with the collaboration of all the co-authors.”The original Article and its accompanying Supplementary Information file have been corrected
Perryvale School District No. 4390 - 03
No full textPhotograph - Staff members at Perryvale School, left to right: D.P. Walsh and left to right, Anne Lehto and Eleanor Telford, Perryvale, AlbertaWalsh, D.P; Lehto, Anne; Telford, Eleano
Zand-slibsegregatie in de Westerschelde
No full textDe bodemsamenstelling van estuaria varieert vaak sterk in zowel horizontale als verticale richting. Met name de ruimtelijke verdeling van zand en slib (zgn. zand-slibsegregatie) is belangrijk, omdat voedingsstoffen en vervuilende stoffen zich voornamelijk hechten aan slib en niet aan zand. Hierdoor is het slibpercentage in de bodem een belangrijke parameter voor ecosystemen en een indicator voor de mogelijke aanwezigheid van bodemvervuiling. Voor een goed beheer van estuaria is kennis en voorspelling van dit fenomeen noodzakelijk. De ruimtelijke verdeling van zand en slib is nog altijd niet goed te verklaren en dus te voorspellen. Dit wordt met name veroorzaakt door de complexe interactie tussen de waterbeweging, sedimenttransport en bodemligging en -samenstelling. De waterbeweging ten gevolge van getij en golven maken het stroombeeld in een estuarium zeer complex. Daarnaast worden erosie- en sedimentatieprocessen van zand en slib nog maar beperkt begrepen. Een veel gebruikte hypothese voor het verklaren van zand-slibsegregatie is "hoe kalmer het water, hoe meer slib". De achtergrond van deze hypothese is dat slib in het algemeen bij lagere stroomsnelheden nog getransporteerd kan worden, terwijl zand inmiddels gesedimenteerd is. Doelstelling van dit onderzoek is het bekijken of er een lokale relatie bestaat tussen waterbeweging enerzijds en de bodemsamenstelling anderzijds. Deze relatie is onderzocht aan de hand van een stromingsmodel en bodemgegevens van de Molenplaat, een intergetijdegebied nabij Hansweert in de Westerschelde. De bodemsamenstellingsgegevens zijn verkregen uit een in 1990 uitgevoerde meetcampagne in de hele Westerschelde. Tijdens deze meetcampagne is de bovenste tien centimeter van de bodem bemonsterd en hiervan is de korrelgrootteverdeling bepaald. In totaal zijn in dit onderzoek 344 monsters gebruikt. Verder zijn secundaire parameters als valsnelheden en dieptegemiddelde kritische snelheden voor het begin van beweging voor zand berekend. Het gebruikte waterbewegingsmodel is het Molenplaatmodel uit 1995. Met dit model zijn dieptegemiddelde (2DH) berekeningen uitgevoerd voor drie verschillende getijsituaties: een springtij, een gemiddeld getij en een doodtij situatie. Tevens is een 3D berekening voor de springtij situatie gemaakt om te bekijken of dit betere waarden voor de waterbeweging oplevert. De monsterpunten zijn toegevoegd aan dit model als observatiepunten, zodat per monsterpunt de waterbeweging gedurende de getijperiode berekend wordt. Door een nabewerking van de modelresultaten zijn verschillende hydrodynamische parameters per monsterpunt berekend, zoals de maximale snelheid, de gemiddelde snelheid, de energiedissipatie etc. Met betrekking tot de relatie tussen sedimenteigenschappen en diepte blijkt dat er tussen 1m +NAP en 2m -NAP hoge concentraties slib in de bodem voorkomen. Op de hoogste delen van de platen (boven 1m +NAP) wordt echter vrijwel geen slib aangetroffen en dieper dan 2m -NAP is de trend ook niet meer waarneembaar. Ook de dso van de zandfractie lijkt samen te hangen met de diepte. Uit de correlatie blijkt: hoe dieper, hoe grover het zand. Combinaties tussen bodemsamenstellingsparameters en hydrodynamische parameters zijn gevisualiseerd in grafieken. Hoewel de waterbeweging van de getijberekeningen in absolute grootte natuurlijk verschilt, laat een vergelijking tussen de verschillende getijomstandigheden zien dat er weinig concrete verschillen zijn. De vormen van de puntenwolken wijken niet erg af wanneer de getijberekeningen worden vergeleken. Wanneer zand en slibpercentages worden uitgezet tegen maximale snelheden, bodemschuifspanningen en energiedissipaties, blijkt er steeds een bepaalde grens te zijn waarboven vrijwel geen slib meer voorkomt. Onder deze grens is echter geen duidelijk verband aanwezig. Zowel grof als fijn materiaal komen voor. Het lijkt erop dat onder deze grens wel de mogelijkheid is voor slib om neer te slaan, maar dat het van meerdere processen afhangt of dit daadwerkelijk gebeurt. Wanneer korreldiameters en aanverwante parameters als dso worden uitgezet tegen de waterbeweging, is steeds een redelijk lineair verband aanwezig. Hoe groter de optredende snelheden en schuifspanningen, hoe grover het sediment.Civil Engineering and Geoscience
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