The Stratigraphic Record of Pre-breakup Geodynamics: Evidence from the Barrow Delta, offshore Northwest Australia

The structural and stratigraphic evolution of rift basins and passive margins has been widely studied, with many analyses demonstrating that delta systems can provide important records of post-rift geodynamic processes. However, the apparent lack of ancient syn-breakup delta systems and the paucity of seismic imaging across continent-ocean boundaries means the transition from continental rifting to oceanic spreading remains poorly understood. The Early Cretaceous Barrow Group of the North Carnarvon Basin, offshore NW Australia was a major deltaic system that formed during the latter stages of continental rifting, and represents a rich sedimentary archive, documenting uplift, subsidence and erosion of the margin. We use a regional database of 2D and 3D seismic and well data to constrain the internal architecture of the Barrow Group. Our results highlight three major depocentres: the Exmouth and Barrow sub-basins, and southern Exmouth Plateau. Over-compaction of pre-Cretaceous sedimentary rocks in the South Carnarvon Basin, and pervasive reworking of Permian and Triassic palynomorphs in the offshore Barrow Group, suggests that the onshore South Carnarvon Basin originally contained a thicker sedimentary succession, which was uplifted and eroded prior to breakup. Backstripping of sedimentary successions encountered in wells in the Exmouth Plateau depocentre indicate anomalously rapid tectonic subsidence (≤0.24 mm yr-1) accommodated Barrow Group deposition, despite evidence for minimal, contemporaneous upper crustal extension. Our results suggest that classic models of uniform extension cannot account for the observations of uplift and subsidence in the North Carnarvon Basin, and may indicate a period of depth-dependent extension or dynamic topography preceding breakup

Confluent Orthogonal Drawings of Syntax Diagrams

We provide a pipeline for generating syntax diagrams (also called railroad diagrams) from context free grammars. Syntax diagrams are a graphical representation of a context free language, which we formalize abstractly as a set of mutually recursive nondeterministic finite automata and draw by combining elements from the confluent drawing, layered drawing, and smooth orthogonal drawing styles. Within our pipeline we introduce several heuristics that modify the grammar but preserve the language, improving the aesthetics of the final drawing.Comment: GD 201

Big-headed marine crocodyliforms and why we must be cautious when using extant species as body length proxies for long-extinct relatives

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The influence of perfusion solution on renal graft viability assessment

BACKGROUND: Kidneys from donors after cardiac or circulatory death are exposed to extended periods of both warm ischemia and intra-arterial cooling before organ recovery. Marshall’s hypertonic citrate (HOC) and Bretschneider’s histidine-tryptophan-ketoglutarate (HTK) preservation solutions are cheap, low viscosity preservation solutions used clinically for organ flushing. The aim of the present study was to evaluate the effects of these two solutions both on parameters used in clinical practice to assess organ viability prior to transplantation and histological evidence of ischemic injury after reperfusion. METHODS: Rodent kidneys were exposed to post-mortem warm ischemia, extended intra-arterial cooling (IAC) (up to 2 h) with preservation solution and reperfusion with either Krebs-Hensleit or whole blood in a transplant model. Control kidneys were either reperfused directly after retrieval or stored in 0.9% saline. Biochemical, immunological and histological parameters were assessed using glutathione-S-transferase (GST) enzymatic assays, polymerase chain reaction and mitochondrial electron microscopy respectively. Vascular function was assessed by supplementing the Krebs-Hensleit perfusion solution with phenylephrine to stimulate smooth muscle contraction followed by acetylcholine to trigger endothelial dependent relaxation. RESULTS: When compared with kidneys reperfused directly post mortem, 2 h of IAC significantly reduced smooth muscle contractile function, endothelial function and upregulated vascular cellular adhesion molecule type 1 (VCAM-1) independent of the preservation solution. However, GST release, vascular resistance, weight gain and histological mitochondrial injury were dependent on the preservation solution used. CONCLUSIONS: We conclude that initial machine perfusion viability tests, including ischemic vascular resistance and GST, are dependent on the perfusion solution used during in situ cooling. HTK-perfused kidneys will be heavier, have higher GST readings and yet reduced mitochondrial ischemic injury when compared with HOC-perfused kidneys. Clinicians should be aware of this when deciding which kidneys to transplant or discard

Stratigraphic record of continental breakup, offshore NW Australia

Continental breakup involves a transition from rapid, fault-controlled syn-rift subsidence to relatively slow, post-breakup subsidence induced by lithospheric cooling. Yet the stratigraphic record of many rifted margins contain syn-breakup unconformities, indicating that episodes of uplift and erosion interrupt this transition. This uplift has been linked to mantle upwelling, depth-dependent extension and/or isostatic rebound. Deciphering the breakup processes recorded by these unconformities and their related rock record is challenging because uplift-associated erosion commonly removes the strata that help constrain the onset and duration of uplift. We examine three major breakup-related unconformities and the intervening rock record in the Lower Cretaceous succession of the Gascoyne and Cuvier margins, offshore NW Australia, using seismic reflection and borehole data. These data show the breakup unconformities are disconformable (non-erosive) in places and angular (erosive) in others. Our recalibration of palynomorph ages from rocks underlying and overlying the unconformities shows: (i) the lowermost unconformity developed between 134.98–133.74 Ma (Intra-Valanginian), probably during the localisation of magma intrusion within continental crust and consequent formation of continent–ocean transition zones (COTZ); (ii) the middle unconformity formed between ca. 134 and 133 Ma (Top Valanginian), possibly coincident with breakup of continental crust and generation of new magmatic (but not oceanic) crust within the COTZs; and (iii) the uppermost unconformity likely developed between ca. 132.5 and 131 Ma (i.e. Intra-Hauterivian), coincident with full continental lithospheric breakup and the onset of seafloor spreading. During unconformity development, uplift was focussed along the continental rift flanks, likely reflecting flexural bending of the crust and landward flow of lower crust and/or lithospheric mantle from beneath areas of localised extension towards the continent (i.e. depth-dependent extension). Our work supports the growing consensus that the ‘breakup unconformity’ is not always a single stratigraphic surface marking the onset of seafloor spreading; multiple unconformities may form and reflect a complex history of uplift and subsidence during continent–ocean transition

DRAM-3 modulates autophagy and promotes cell survival in the absence of glucose

Macroautophagy is a membrane-trafficking process that delivers cytoplasmic constituents to lysosomes for degradation. The process operates under basal conditions as a mechanism to turnover damaged or misfolded proteins and organelles. As a result, it has a major role in preserving cellular integrity and viability. In addition to this basal function, macroautophagy can also be modulated in response to various forms of cellular stress, and the rate and cargoes of macroautophagy can be tailored to facilitate appropriate cellular responses in particular situations. The macroautophagy machinery is regulated by a group of evolutionarily conserved autophagy-related (ATG) proteins and by several other autophagy regulators, which either have tissue-restricted expression or operate in specific contexts. We report here the characterization of a novel autophagy regulator that we have termed DRAM-3 due to its significant homology to damage-regulated autophagy modulator (DRAM-1). DRAM-3 is expressed in a broad spectrum of normal tissues and tumor cells, but different from DRAM-1, DRAM-3 is not induced by p53 or DNA-damaging agents. Immunofluorescence studies revealed that DRAM-3 localizes to lysosomes/autolysosomes, endosomes and the plasma membrane, but not the endoplasmic reticulum, phagophores, autophagosomes or Golgi, indicating significant overlap with DRAM-1 localization and with organelles associated with macroautophagy. In this regard, we further proceed to show that DRAM-3 expression causes accumulation of autophagosomes under basal conditions and enhances autophagic flux. Reciprocally, CRISPR/Cas9-mediated disruption of DRAM-3 impairs autophagic flux confirming that DRAM-3 is a modulator of macroautophagy. As macroautophagy can be cytoprotective under starvation conditions, we also tested whether DRAM-3 could promote survival on nutrient deprivation. This revealed that DRAM-3 can repress cell death and promote long-term clonogenic survival of cells grown in the absence of glucose. Interestingly, however, this effect is macroautophagy-independent. In summary, these findings constitute the primary characterization of DRAM-3 as a modulator of both macroautophagy and cell survival under starvation conditions

Chimiotherapie des angiosarcomes de Kaposi au service d'oncologie medicale de L'hopital General de Yaounde, Cameroun

Compte tenu de la séroprévalence de l'infection à VIH/SIDA au Cameroun (5,5%), le service d'oncologie médicale de l'Hôpital Général de Yaoundé, prend en charge par chimiothérapie les patients porteurs d'angiosarcome de Kaposi. Nous avons voulu évaluer la chimiothérapie de l'angiosarcome de Kaposi dans notre service. Une étude descriptive rétrospective a été menée sur une année. Les patients recrutés ont été ceux avec un diagnostic d'angiosarcome de Kaposi. Les données collectées étaient les suivantes : le sexe, l'âge, la localisation, les pathologies associées, la chimiothérapie administrée, les réponses et la tolérance. Les deux dernières données ont été évaluées selon les critères de l'OMS. Au cours de cette année, 57 patients ont été reçus pour un angiosarcome de Kaposi dont 31 (54,4%) hommes et 26 (47,6%) femmes. Les âges extrêmes ont été 14 et 76 ans avec une moyenne de 39,05 ans. La localisation principale était tégumentaire (65,6% des localisations), diffuse pour la plupart des cas. Des 43 patients testés, 38 (88,4%) avaient une sérologie VIH positive et 5 (11,6%) négatifs. Dans notre échantillon, 84,6% ont reçu une polychimiothérapie associant la doxorubucine, la bléomycine et la vincristine. Seuls 20 patients des 38 séropositifs soit 52,6% ont reçu des antiretroviraux. La réponse partielle a été objectivée chez 16 sur 19 (84,2%) de nos patients. La toxicité observée a été hématologique et 13 patients (22,8%) ont été transfusés pour anémie. Nous concluons que la chimiothérapie est bénéfique dans le traitement du sarcome de Kaposi. Des études comparatives ultérieures précisent si le traitement de ces patients améliore la qualité de vie et la survie. Clinics in Mother and Child Health Vol. 3(1) 2006: 469-47