1,414 research outputs found

    The Structure and Function of Serum Opacity Factor: A Unique Streptococcal Virulence Determinant That Targets High-Density Lipoproteins

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    Serum opacity factor (SOF) is a virulence determinant expressed by a variety of streptococcal and staphylococcal species including both human and animal pathogens. SOF derives its name from its ability to opacify serum where it targets and disrupts the structure of high-density lipoproteins resulting in formation of large lipid vesicles that cause the serum to become cloudy. SOF is a multifunctional protein and in addition to its opacification activity, it binds to a number of host proteins that mediate adhesion of streptococci to host cells, and it plays a role in resistance to phagocytosis in human blood. This article will provide an overview of the structure and function of SOF, its role in the pathogenesis of streptococcal infections, its vaccine potential, its prevalence and distribution in bacteria, and the molecular mechanism whereby SOF opacifies serum and how an understanding of this mechanism may lead to therapies for reducing high-cholesterol concentrations in blood, a major risk factor for cardiovascular disease

    Rolling open Earth’s deepest forearc basin

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    The Weber Deep—a 7.2-km-deep forearc basin within the tightly curved Banda arc of eastern Indonesia—is the deepest point of the Earth’s oceans not within a trench. Several models have been proposed to explain the tectonic evolution of the Banda arc in the context of the ongoing (ca. 23 Ma–present) Australia–Southeast Asia collision, but no model explicitly accounts for how the Weber Deep achieved its anomalous depth. Here we propose that the Weber Deep formed by forearc extension driven by eastward subduction rollback. Substantial lithospheric extension in the upper plate was accommodated by a major, previously unidentified, low-angle normal fault system we name the “Banda detachment.” High-resolution bathymetry data reveal that the Banda detachment is exposed underwater over much of its 120 km down-dip and 450 km lateral extent, having produced the largest bathymetric expression of any fault discernable in the world’s oceans. The Banda arc is a modern analogue for highly extended terranes preserved in the many regions that may similarly have “rolled open” behind migrating subduction zones

    Geological aspects of Banda Sea ecosystems and how they shape the oceanographical profile

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    The Banda Sea is a collage of young oceanic basins and fragmented Australian continental crust located at the heart of the Australia–SE Asia collision zone where Australian and Asian biogeographic regions converge. The formation of the sea was governed by the southeastward rollback of the Banda Slab since c. 16 Ma, which in its wake opened new oceanic basins and extended and fragmented Australian crust. These Australian crustal fragments are today either stranded within the Banda Sea where they form the prominent submarine 'Banda Ridges', or now reside as thrust-sheets on the NW Australian shelf after being transported all the way to the southern Banda Arc. The deepest part of the Banda Sea, the 7.2 km Weber Deep, was formed by extreme lithospheric extension that occured in the latter stages of Banda Slab rollback. This extension was accommodated by the vast low-angle 'Banda Detachment', which operated above the subducted fringes of the Australian continental margin

    Quality classification affects firmness of ground beef patties from the chuck roll

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    Consumers often use color as the main criteria in selecting meat products, and they associate a bright red color with freshness. Longer display life without discoloration can result in more opportunities to sell the product and greater potential for profit. Flavor, juiciness, and tenderness are also associated with consumer satisfaction. Although grinding offers an opportunity to mechanically minimize differences in tenderness, product quality can affect these sensory properties of ground beef. The objective of this study was to determine the effects of three quality classifications and their combinations on ground beef patty display color stability and sensory attributes evaluated by a trained sensory panel and consumer panel

    Temperate Pasture and Sheep Performance Under Radiata Pine and In Open Pasture

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    Forage production from years 4 to 6 of an agroforestry system at 400-600 trees per ha and pasture alone were compared for a temperate sub-humid environment. Forage production was best for lucerne pasture followed by phalaris/clover and cocksfoot/clover, and least for ryegrass/clover and the ryegrass only pastures. Total pasture production in the agroforest relative to the open pasture was from 10% more for phalaris to 20% less for lucerne. Sheep carrying capacity over all pastures was 14.6 sheep/ha in the open and 11.8 sheep/ha in the agroforest and varied by ±15% according to the pasture types

    Earthquakes and tsunamis caused by low-angle normal faulting in the Banda Sea, Indonesia

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    As the world's largest archipelagic country in Earth's most active tectonic region, Indonesia faces a substantial earthquake and tsunami threat. Understanding this threat is a challenge because of the complex tectonic environment, the paucity of observed data and the limited historical record. Here we combine information from recent studies of the geology of Indonesia's Banda Sea with Global Positioning System observations of crustal motion and an analysis of historical large earthquakes and tsunamis there. We show that past destructive earthquakes were not caused by the supposed megathrust of the Banda outer arc as previously thought but are due to a vast submarine normal fault system recently discovered along the Banda inner arc. Instead of being generated by coseismic seafloor displacement, we find the tsunamis were more likely caused by earthquake-triggered submarine slumping along the fault's massive scarp, the Weber Deep. This would make the Banda detachment representative not only as a modern analogue for terranes hyper-extended by slab rollback but also for the generation of earthquakes and tsunamis by a submarine extensional fault system. Our findings suggest that low-angle normal faults in the Banda Sea generate large earthquakes, which in turn can generate tsunamis due to earthquake-triggered slumping. Low-angle normal faults in the Banda Sea have caused large earthquakes that indirectly generated tsunamis due to earthquake-triggered submarine slumping, according to an analysis of historical earthquake and tsunami events and GPS observations.Peer reviewe

    Balancing pedagogical innovation with psychological safety?

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    Authentic assessments are designed to evaluate knowledge and skills that are relevant for students’ life beyond university, emphasising practical, applied skills. They offer an alternative to assessments that don’t explicitly foster transferability of skills. The present study examined undergraduate student perceptions of authentic and traditional assessments (N = 150). We used a qualitative story completion methodology to examine three domains: student’s emotional responses to authentic and traditional assessment forms, student’s perceptions of how different assessment types may benefit their employability, and student’s preferences for pedagogical support with authentic assessments. A qualitative content analysis revealed students generally perceive authentic, novel assessments to be exciting, motivating and inspirational; however, this was accompanied by feelings of uncertainty and unfamiliarity. More traditional assessments (e.g. essays and multiple-choice-question examinations) elicited feelings of comfort and preparedness, but students also felt worried, bored and unexcited by these assessments. Students appreciated creative freedom when lecturers set traditional assessments but would like more consideration of their feelings and need for support in authentic assessments. Hence, we argue, when advocating for authentic assessment, there is a balance to be struck between innovation and challenge, ensuring sufficient support for student’s psychological safety and feelings of comfort. Implications for practice are discussed

    ANGPTL4 variants E40K and T266M are associated with lower fasting triglyceride levels in Non-Hispanic White Americans from the Look AHEAD Clinical Trial

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    <p>Abstract</p> <p>Background</p> <p>Elevated triglyceride levels are a risk factor for cardiovascular disease. Angiopoietin-like protein 4 (Angptl4) is a metabolic factor that raises plasma triglyceride levels by inhibiting lipoprotein lipase (LPL). In non-diabetic individuals, the <it>ANGPTL4 </it>coding variant E40K has been associated with lower plasma triglyceride levels while the T266M variant has been associated with more modest effects on triglyceride metabolism. The objective of this study was to determine whether ANGPTL4 E40K and T266M are associated with triglyceride levels in the setting of obesity and T2D, and whether modification of triglyceride levels by these genetic variants is altered by a lifestyle intervention designed to treat T2D.</p> <p>Methods</p> <p>The association of <it>ANGPTL4 </it>E40K and T266M with fasting triglyceride levels was investigated in 2,601 participants from the Look AHEAD Clinical Trial, all of whom had T2D and were at least overweight. Further, we tested for an interaction between genotype and treatment effects on triglyceride levels.</p> <p>Results</p> <p>Among non-Hispanic White Look AHEAD participants, <it>ANGPTL4 </it>K40 carriers had mean triglyceride levels of 1.61 ± 0.62 mmol/L, 0.33 mmol/L lower than E40 homozygotes (p = 0.001). Individuals homozygous for the minor M266 allele (MAF 30%) had triglyceride levels of 1.75 ± 0.58 mmol/L, 0.24 mmol/L lower than T266 homozygotes (p = 0.002). The association of the M266 with triglycerides remained significant even after removing K40 carriers from the analysis (p = 0.002). There was no interaction between the weight loss intervention and genotype on triglyceride levels.</p> <p>Conclusions</p> <p>This is the first study to demonstrate that the <it>ANGPTL4 </it>E40K and T266M variants are associated with lower triglyceride levels in the setting of T2D. In addition, our findings demonstrate that <it>ANGPTL4 </it>genotype status does not alter triglyceride response to a lifestyle intervention in the Look AHEAD study.</p

    Generation and use of functionalised hydrogels that can rapidly sample infected surfaces

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    This paper outlined our method for developing polymer-linked contact lens type materials for rapid detection and differentiation of Gram-positive, Gram-negative bacteria and fungi in infected corneas. It can be applied to both model synthetic or ex-vivo corneal models and has been successfully trialed in an initial efficacy tested animal study. First a hydrogel substrate for the swab material is selected, we have demonstrated selective swabs using a glycerol monomethacrylate hydrogel. Alternatively any commercial material with carboxylic acid functional groups is suitable but risks nonspecific adhesion. This is then functionalised via use of N-hydroxysuccinimide reaction with amine groups on the specified highly branched polymer ligand (either individually gram negative, gram positive or fungal binding polymers or a combination of all three can be employed for desired sensing application). The hydrogel is then cut into swabs suitable for sampling, used, and then the presence of gram positive, game negative and fungi are disclosed by the sequential addition of dyes (fluorescent vancomycin, fluorescein isothiocyanate and calcofluor white). In summary this method presents: Method to produce glycerol monomethacrylate hydrogels to minimize nonspecific binding Methods of attaching pathogen binding highly branched polymers to produce selective hydrogel swabs Method for disclosing bound pathogens to this swab using sequential dye additio
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