2,313 research outputs found
Semantics for first-order affine inductive data types via slice categories
Affine type systems are substructural type systems where copying of
information is restricted, but discarding of information is permissible at all
types. Such type systems are well-suited for describing quantum programming
languages, because copying of quantum information violates the laws of quantum
mechanics. In this paper, we consider a first-order affine type system with
inductive data types and present a novel categorical semantics for it. The most
challenging aspect of this interpretation comes from the requirement to
construct appropriate discarding maps for our data types which might be defined
by mutual/nested recursion. We show how to achieve this for all types by taking
models of a first-order linear type system whose atomic types are discardable
and then presenting an additional affine interpretation of types within the
slice category of the model with the tensor unit. We present some concrete
categorical models for the language ranging from classical to quantum. Finally,
we discuss potential ways of dualising and extending our methods and using them
for interpreting coalgebraic and lazy data types
Sialylation of campylobacter jejuni lipo-oligosaccharides: impact on phagocytosis and cytokine production in mice
<p>Background:
Guillain-Barré syndrome (GBS) is a post-infectious polyradiculoneuropathy, frequently associated with antecedent Campylobacter jejuni (C. jejuni) infection. The presence of sialic acid on C. jejuni lipo-oligosaccharide (LOS) is considered a risk factor for development of GBS as it crucially determines the structural homology between LOS and gangliosides, explaining the induction of cross-reactive neurotoxic antibodies. Sialylated C. jejuni are recognised by TLR4 and sialoadhesin; however, the functional implications of these interactions in vivo are unknown.</p>
<p>Methodology/Principal Findings:
In this study we investigated the effects of bacterial sialylation on phagocytosis and cytokine secretion by mouse myeloid cells in vitro and in vivo. Using fluorescently labelled GM1a/GD1a ganglioside-mimicking C. jejuni strains and corresponding (Cst-II-mutant) control strains lacking sialic acid, we show that sialylated C. jejuni was more efficiently phagocytosed in vitro by BM-MΦ, but not by BM-DC. In addition, LOS sialylation increased the production of IL-10, IL-6 and IFN-β by both BM-MΦ and BM-DC. Subsequent in vivo experiments revealed that sialylation augmented the deposition of fluorescent bacteria in splenic DC, but not macrophages. In addition, sialylation significantly amplified the production of type I interferons, which was independent of pDC.</p>
<p>Conclusions/Significance:
These results identify novel immune stimulatory effects of C. jejuni sialylation, which may be important in inducing cross-reactive humoral responses that cause GBS</p>
First Dinosaur Tracks from the Arabian Peninsula
Background: The evolutionary history of Mesozoic terrestrial vertebrates from the Arabian Peninsula is virtually unknown. Despite vast exposures of rocky outcrops, only a handful of fossils have yet been described from the region. Here we report a multi-taxon dinosaur track assemblage near Madar village, 47 km north of Sana’a, Republic of Yemen. This represents the first dinosaur tracksite from the Arabian Peninsula, and the only multi-taxon dinosaur ichnosite in the Middle East. Methodology/Findings: Measurements were taken directly from trackway impressions, following standard ichnological conventions. The presence of bipedal trackmakers is evidenced by a long series of pes imprints preserving smoothly rounded posterior margins, no evidence of a hallux, bluntly rounded digit tips and digital divarication angles characteristic of ornithopod dinosaurs. Nearby, eleven parallel quadrupedal trackways document a sauropod herd that included large and small individuals traveling together. Based on the morphology of manus impressions along with a narrow-gauged stance, the quadrupedal trackways were made by non-titanosauriform neosauropods. Additional isolated tracks and trackways of sauropod and ornithopod dinosaurs are preserved nearby. Conclusions/Significance: Taken together, these discoveries present the most evocative window to date into the evolutionary history of dinosaurs of the Arabian Peninsula. Given the limited Mesozoic terrestrial record from the region, this discovery is of both temporal and geographic significance, and massive exposures of similarly-aged outcrops nearby offe
Membrane TNF confers protection to acute mycobacterial infection
BACKGROUND: Tumour necrosis factor (TNF) is crucial for the control of mycobacterial infection as TNF deficient (KO) die rapidly of uncontrolled infection with necrotic pneumonia. Here we investigated the role of membrane TNF for host resistance in knock-in mice with a non-cleavable and regulated allele (mem-TNF). METHODS: C57BL/6, TNF KO and mem-TNF mice were infected with M. tuberculosis H37Rv (Mtb at 100 CFU by intranasal administration) and the survival, bacterial load, lung pathology and immunological parameters were investigated. Bone marrow and lymphocytes transfers were used to test the role of membrane TNF to confer resistance to TNF KO mice. RESULTS: While TNF-KO mice succumbed to infection within 4–5 weeks, mem-TNF mice recruited normally T cells and macrophages, developed mature granuloma in the lung and controlled acute Mtb infection. However, during the chronic phase of infection mem-TNF mice succumbed to disseminated infection with necrotic pneumonia at about 150 days. Reconstitution of irradiated TNF-KO mice with mem-TNF derived bone marrow cells, but not with lymphocytes, conferred host resistance to Mtb infection in TNF-KO mice. CONCLUSION: Membrane expressed TNF is sufficient to allow cell-cell signalling and control of acute Mtb infection. Bone marrow cells, but not lymphocytes from mem-TNF mice confer resistance to infection in TNF-KO mice. Long-term infection control with chronic inflammation likely disrupting TNF mediated cell-cell signalling, additionally requires soluble TNF
BSE Case Associated with Prion Protein Gene Mutation
Bovine spongiform encephalopathy (BSE) is a transmissible spongiform encephalopathy (TSE) of cattle and was first detected in 1986 in the United Kingdom. It is the most likely cause of variant Creutzfeldt-Jakob disease (CJD) in humans. The origin of BSE remains an enigma. Here we report an H-type BSE case associated with the novel mutation E211K within the prion protein gene (Prnp). Sequence analysis revealed that the animal with H-type BSE was heterozygous at Prnp nucleotides 631 through 633. An identical pathogenic mutation at the homologous codon position (E200K) in the human Prnp has been described as the most common cause of genetic CJD. This finding represents the first report of a confirmed case of BSE with a potential pathogenic mutation within the bovine Prnp gene. A recent epidemiological study revealed that the K211 allele was not detected in 6062 cattle from commercial beef processing plants and 42 cattle breeds, indicating an extremely low prevalence of the E211K variant (less than 1 in 2000) in cattle
Design choices made by target users for a pay-for-performance program in primary care: an action research approach
Contains fulltext :
110832.pdf (publisher's version ) (Open Access)BACKGROUND: International interest in pay-for-performance (P4P) initiatives to improve quality of health care is growing. Current programs vary in the methods of performance measurement, appraisal and reimbursement. One may assume that involvement of health care professionals in the goal setting and methods of quality measurement and subsequent payment schemes may enhance their commitment to and motivation for P4P programs and therefore the impact of these programs. We developed a P4P program in which the target users were involved in decisions about the P4P methods. METHODS: For the development of the P4P program a framework was used which distinguished three main components: performance measurement, appraisal and reimbursement. Based on this framework design choices were discussed in two panels of target users using an adapted Delphi procedure. The target users were 65 general practices and two health insurance companies in the South of the Netherlands. RESULTS: Performance measurement was linked to the Dutch accreditation program based on three domains (clinical care, practice management and patient experience). The general practice was chosen as unit of assessment. Relative standards were set at the 25th percentile of group performance. The incentive for clinical care was set twice as high as the one for practice management and patient experience. Quality scores were to be calculated separately for all three domains, and for both the quality level and the improvement of performance. The incentive for quality level was set thrice as high as the one for the improvement of performance. For reimbursement, quality scores were divided into seven levels. A practice with a quality score in the lowest group was not supposed to receive a bonus. The additional payment grew proportionally for each extra group. The bonus aimed at was on average 5% to 10% of the practice income. CONCLUSIONS: Designing a P4P program for primary care with involvement of the target users gave us an insight into their motives, which can help others who need to discuss similar programs. The resulting program is in line with target users' views and assessments of relevance and applicability. This may enhance their commitment to the program as was indicated by the growing number of voluntary participants after a successfully performed field test during the procedure. The elements of our framework can be very helpful for others who are developing or evaluating a P4P program
Determining Peptide Partitioning Properties via Computer Simulation
The transfer of polypeptide segments into lipid bilayers to form transmembrane helices represents the crucial first step in cellular membrane protein folding and assembly. This process is driven by complex and poorly understood atomic interactions of peptides with the lipid bilayer environment. The lack of suitable experimental techniques that can resolve these processes both at atomic resolution and nanosecond timescales has spurred the development of computational techniques. In this review, we summarize the significant progress achieved in the last few years in elucidating the partitioning of peptides into lipid bilayer membranes using atomic detail molecular dynamics simulations. Indeed, partitioning simulations can now provide a wealth of structural and dynamic information. Furthermore, we show that peptide-induced bilayer distortions, insertion pathways, transfer free energies, and kinetic insertion barriers are now accurate enough to complement experiments. Further advances in simulation methods and force field parameter accuracy promise to turn molecular dynamics simulations into a powerful tool for investigating a wide range of membrane active peptide phenomena
Making mathematics and science integration happen: key aspects of practice
The integration of mathematics and science teaching and learning facilitates student learning, engagement, motivation, problem-solving, criticality and real-life application. However, the actual implementation of an integrative approach to the teaching and learning of both subjects at classroom level, with in-service teachers working collaboratively, at second-level education, is under-researched due to the complexities of school-based research. This study reports on a year-long case study on the implementation of an integrated unit of learning on distance, speed and time, within three second-level schools in Ireland. This study employed a qualitative approach and examined the key aspects of practice that impact on the integration of mathematics and science teaching and learning. We argue that teacher perspective, teacher knowledge of the ‘other subject’ and of technological pedagogical content knowledge (TPACK), and teacher collaboration and support all impact on the implementation of an integrative approach to mathematics and science education
Cannabidiol in clinical and preclinical anxiety research. A systematic review into concentration-effect relations using the IB-de-risk tool
BACKGROUND: Preclinical research suggests that cannabidiol (CBD) may have therapeutic potential in pathological anxiety. Dosing guidelines to inform future human studies are however lacking. AIM: We aimed to predict the therapeutic window for anxiety-reducing effects of CBD in humans based on preclinical models. METHODS: We conducted two systematic searches in PubMed and Embase up to August 2021, into pharmacokinetic (PK) and pharmacodynamic (PD) data of systemic CBD exposure in humans and animals, which includes anxiety-reducing and potential side effects. Risk of bias was assessed with SYRCLE's RoB tool and Cochrane RoB 2.0. A control group was an inclusion criterion in outcome studies. In human outcome studies, randomisation was required. We excluded studies that co-administered other substances. We used the IB-de-risk tool for a translational integration of outcomes. RESULTS: We synthesised data from 87 studies. For most observations (70.3%), CBD had no effect on anxiety outcomes. There was no identifiable relation between anxiety outcomes and drug levels across species. In all species (humans, mice, rats), anxiety-reducing effects seemed to be clustered in certain concentration ranges, which differed between species. DISCUSSION: A straightforward dosing recommendation was not possible, given variable concentration-effect relations across species, and no consistent linear effect of CBD on anxiety reduction. Currently, these results raise questions about the broad use as a drug for anxiety. Meta-analytic studies are needed to quantitatively investigate drug efficacy, including aspects of anxiety symptomatology. Acute and (sub)chronic dosing studies with integrated PK and PD outcomes are required for substantiated dose recommendations
Multiple Deeply Divergent Denisovan Ancestries in Papuans
Genome sequences are known for two archaic
hominins—Neanderthals and Denisovans—which
interbred with anatomically modern humans as
they dispersed out of Africa. We identified high-confidence
archaic haplotypes in 161 new genomes
spanning 14 island groups in Island Southeast
Asia and New Guinea and found large stretches of
DNA that are inconsistent with a single introgressing
Denisovan origin. Instead, modern Papuans carry
hundreds of gene variants from two deeply divergent
Denisovan lineages that separated over 350
thousand years ago. Spatial and temporal structure
among these lineages suggest that introgression
from one of these Denisovan groups predominantly
took place east of the Wallace line and continued
until near the end of the Pleistocene. A third Denisovan
lineage occurs in modern East Asians. This
regional mosaic suggests considerable complexity
in archaic contact, with modern humans interbreeding
with multiple Denisovan groups that were
geographically isolated from each other over deep
evolutionary time
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