1,562 research outputs found
Narratives of resistance: (Re) Telling the story of the HIV/AIDS movement – Because the lives and legacies of Black, Indigenous, and People of Colour communities depend on it
Centering the narratives of the intersectional struggles within the HIV movement for Indigenous sovereignty, Black and People of Colour liberation, and LGBTQ rights tirelessly fought for by Black, Indigenous, and People of Colour communities legitimates their lives and legacies within the movement; and the relevance of a focused response to the HIV epidemic that continues to wreak devastation in these communities. The recent political push for a post-HIV era solely centers the realities of middle-class white, gay men and has genocidal implications for Black, Indigenous, and People of Colour communities
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Functional Brain Hyperactivations Are Linked to an Electrophysiological Measure of Slow Interhemispheric Transfer Time after Pediatric Moderate/Severe Traumatic Brain Injury.
Increased task-related blood oxygen level dependent (BOLD) activation is commonly observed in functional magnetic resonance imaging (fMRI) studies of moderate/severe traumatic brain injury (msTBI), but the functional relevance of these hyperactivations and how they are linked to more direct measures of neuronal function remain largely unknown. Here, we investigated how working memory load (WML)-dependent BOLD activation was related to an electrophysiological measure of interhemispheric transfer time (IHTT) in a sample of 18 msTBI patients and 26 demographically matched controls from the UCLA RAPBI (Recovery after Pediatric Brain Injury) study. In the context of highly similar fMRI task performance, a subgroup of TBI patients with slow IHTT had greater BOLD activation with higher WML than both healthy control children and a subgroup of msTBI patients with normal IHTT. Slower IHTT treated as a continuous variable was also associated with BOLD hyperactivation in the full TBI sample and in controls. Higher WML-dependent BOLD activation was related to better performance on a clinical cognitive performance index, an association that was more pronounced within the patient group with slow IHTT. Our previous work has shown that a subgroup of children with slow IHTT after pediatric msTBI has increased risk for poor white matter organization, long-term neurodegeneration, and poor cognitive outcome. BOLD hyperactivations after msTBI may reflect neuronal compensatory processes supporting higher-order capacity demanding cognitive functions in the context of inefficient neuronal transfer of information. The link between BOLD hyperactivations and slow IHTT adds to the multi-modal validation of this electrophysiological measure as a promising biomarker
Mathematical modelling of fibre-enhanced perfusion inside\ud a tissue-engineering bioreactor
We develop a simple mathematical model for forced flow of culture medium through a porous scaffold in a tissue- engineering bioreactor. Porous-walled hollow fibres penetrate the scaffold and act as additional sources of culture medium. The model, based on Darcy’s law, is used to examine the nutrient and shear-stress distributions throughout the scaffold. We consider several configurations of fibres and inlet and outlet pipes. Compared with a numerical solution of the full Navier–Stokes equations within the complex scaffold geometry, the modelling approach is cheap, and does not require knowledge of the detailed microstructure of the particular scaffold being used. The potential of this approach is demonstrated through quantification of the effect the additional flow from the fibres has on the nutrient and shear-stress distribution
Microbial impacts on 99mTc migration through sandstone under highly alkaline conditions relevant to radioactive waste disposal
Geological disposal of intermediate level radioactive waste in the UK is planned to involve the use of cementitious materials, facilitating the formation of an alkali-disturbed zone within the host rock. The biogeochemical processes that will occur in this environment, and the extent to which they will impact on radionuclide migration, are currently poorly understood. This study investigates the impact of biogeochemical processes on the mobility of the radionuclide technetium, in column experiments designed to be representative of aspects of the alkali-disturbed zone. Results indicate that microbial processes were capable of inhibiting 99mTc migration through columns, and X-ray radiography demonstrated that extensive physical changes had occurred to the material within columns where microbiological activity had been stimulated. The utilisation of organic acids under highly alkaline conditions, generating H2 and CO2, may represent a mechanism by which microbial processes may alter the hydraulic conductivity of a geological environment. Column sediments were dominated by obligately alkaliphilic H2-oxidising bacteria, suggesting that the enrichment of these bacteria may have occurred as a result of H2 generation during organic acid metabolism. The results from these experiments show that microorganisms are able to carry out a number of processes under highly alkaline conditions that could potentially impact on the properties of the host rock surrounding a geological disposal facility for intermediate level radioactive waste
A Systematically Reduced Mathematical Model for Organoid Expansion
Organoids are three-dimensional multicellular tissue constructs. When cultured in vitro, they recapitulate the structure, heterogeneity, and function of their in vivo counterparts. As awareness of the multiple uses of organoids has grown, e.g. in drug discovery and personalised medicine, demand has increased for low-cost and efficient methods of producing them in a reproducible manner and at scale. Here we focus on a bioreactor technology for organoid production, which exploits fluid flow to enhance mass transport to and from the organoids. To ensure large numbers of organoids can be grown within the bioreactor in a reproducible manner, nutrient delivery to, and waste product removal from, the organoids must be carefully controlled. We develop a continuum mathematical model to investigate how mass transport within the bioreactor depends on the inlet flow rate and cell seeding density, focusing on the transport of two key metabolites: glucose and lactate. We exploit the thin geometry of the bioreactor to systematically simplify our model. This significantly reduces the computational cost of generating model solutions, and provides insight into the dominant mass transport mechanisms. We test the validity of the reduced models by comparison with simulations of the full model. We then exploit our reduced mathematical model to determine, for a given inlet flow rate and cell seeding density, the evolution of the spatial metabolite distributions throughout the bioreactor. To assess the bioreactor transport characteristics, we introduce metrics quantifying glucose conversion (the ratio between the total amounts of consumed and supplied glucose), the maximum lactate concentration, the proportion of the bioreactor with intolerable lactate concentrations, and the time when intolerable lactate concentrations are first experienced within the bioreactor. We determine the dependence of these metrics on organoid-line characteristics such as proliferation rate and rate of glucose consumption per cell. Finally, for a given organoid line, we determine how the distribution of metabolites and the associated metrics depend on the inlet flow rate. Insights from this study can be used to inform bioreactor operating conditions, ultimately improving the quality and number of bioreactor-expanded organoids
Functional 3D architecture in an intrinsically disordered E3 ligase domain facilitates ubiquitin transfer
Funding: Wellcome Trust Investigator Awards (098391/Z/12/Z and 217196/Z/19/Z) and Cancer Research UK Programme grant (C434/A21747) to R.T.H., Wellcome Trust Studentship (109113/Z/15/Z) to P.M., Wellcome Trust Collaborative Award (215539) and multiuser equipment grant (104833) to S.J.M. Additionally J.C.P. thanks the Scottish Universities Physics Alliance (SUPA) and the University of St. Andrews for financial support.The human genome contains an estimated 600 ubiquitin E3 ligases, many of which are single-subunit E3s (ssE3s) that can bind to both substrate and ubiquitin-loaded E2 (E2~Ub). Within ssE3s structural disorder tends to be located in substrate binding and domain linking regions. RNF4 is a ssE3 ligase with a C-terminal RING domain and disordered N-terminal region containing SUMO Interactions Motifs (SIMs) required to bind SUMO modified substrates. Here we show that, although the N-terminal region of RNF4 bears no secondary structure, it maintains a compact global architecture primed for SUMO interaction. Segregated charged regions within the RNF4 N-terminus promote compaction, juxtaposing RING domain and SIMs to facilitate substrate ubiquitination. Mutations that induce a more extended shape reduce ubiquitination activity. Our result offer insight into a key step in substrate ubiquitination by a member of the largest ubiquitin ligase subtype and reveal how a defined architecture within a disordered region contributes to E3 ligase function.Publisher PDFPeer reviewe
A consensus prognostic gene expression classifier for ER positive breast cancer.
BACKGROUND: A consensus prognostic gene expression classifier is still elusive in heterogeneous diseases such as breast cancer. RESULTS: Here we perform a combined analysis of three major breast cancer microarray data sets to hone in on a universally valid prognostic molecular classifier in estrogen receptor (ER) positive tumors. Using a recently developed robust measure of prognostic separation, we further validate the prognostic classifier in three external independent cohorts, confirming the validity of our molecular classifier in a total of 877 ER positive samples. Furthermore, we find that molecular classifiers may not outperform classical prognostic indices but that they can be used in hybrid molecular-pathological classification schemes to improve prognostic separation. CONCLUSION: The prognostic molecular classifier presented here is the first to be valid in over 877 ER positive breast cancer samples and across three different microarray platforms. Larger multi-institutional studies will be needed to fully determine the added prognostic value of molecular classifiers when combined with standard prognostic factors
Understanding language learning in Malta
The Ministry for Education and Employment (MEDE) in
Malta has a strategic objective to maintain and strengthen
standards of English language proficiency within the school
education system so that Malta remains a high-performing
Commonwealth and European Union country. This should
perpetuate the existing, successful provision of bilingual
education (Mifsud and Vella forthcoming 2017, Ministry
of Education 2016) which prepares individuals from early
on in life, who are equally fluent in Maltese and English, for
the global employment market. To this end, the Ministry
and Cambridge English Language Assessment entered into
an agreement for an integrated solution which included
the benchmarking of student English language levels in
the school sector (Year 1) and the institutional capacitybuilding
of Maltese teachers (Year 2).
Cambridge English Language Assessment, in collaboration
with the Ministry, conducted the Year 1 benchmarking
project, which aimed at presenting a snapshot of English
language proficiency in two key grades at Primary and
Secondary education in relation to international standards,
namely the Common European Framework of Reference
(CEFR, Council of Europe 2001). The six CEFR reference
levels are now widely accepted as the international
standard for grading an individual’s language proficiency.
In addition to benchmarking learner proficiency, a
comprehensive profile of learner, teacher and parent
attitudes towards English language education in
Malta was investigated. This aspect of the project was
designed to provide a comprehensive profile of the
Maltese educational context by bringing together views
from the main stakeholders. Results also feed into the
Ministry’s desire to deliver institutional capacity-building
in assessment and teaching methodology, a strategic
plan for continuous professional development of the
teaching cadre, and potential international certification for
learners and teachers.peer-reviewe
Fatal S. aureus Hemorrhagic Pneumonia: Genetic Analysis of a Unique Clinical Isolate Producing both PVL and TSST-1
In 2008, an unusual strain of methicillin-sensitive Staphylococcus aureus (MSSA68111), producing both Panton-Valentine leukocidin (PVL) and toxic shock syndrome toxin-1 (TSST-1), was isolated from a fatal case of necrotizing pneumonia. Because PVL/TSST-1 co-production in S. aureus is rare, we characterized the molecular organization of these toxin genes in strain 68111. MSSA68111 carries the PVL genes within a novel temperate prophage we call ФPVLv68111 that is most similar, though not identical, to phage ФPVL – a phage type that is relatively rare worldwide. The TSST-1 gene (tst) in MSSA68111 is carried on a unique staphylococcal pathogenicity island (SaPI) we call SaPI68111. Features of SaPI68111 suggest it likely arose through multiple major recombination events with other known SaPIs. Both ФPVLv68111 and SaPI68111 are fully mobilizable and therefore transmissible to other strains. Taken together, these findings suggest that hypervirulent S. aureus have the potential to emerge worldwide
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