1,999 research outputs found
Electrically tunable multi-terminal SQUID-on-tip
We present a new nanoscale superconducting quantum interference device
(SQUID) whose interference pattern can be shifted electrically in-situ. The
device consists of a nanoscale four-terminal/four-junction SQUID fabricated at
the apex of a sharp pipette using a self-aligned three-step deposition of Pb.
In contrast to conventional two-terminal/two-junction SQUIDs that display
optimal sensitivity when flux biased to about a quarter of the flux quantum,
the additional terminals and junctions allow optimal sensitivity at arbitrary
applied flux, thus eliminating the magnetic field "blind spots". We demonstrate
spin sensitivity of 5 to 8 over a continuous field
range of 0 to 0.5 T, with promising applications for nanoscale scanning
magnetic imaging
Full-duplex acoustic interaction system for cognitive experiments with cetaceans
Cetaceans show high cognitive abilities and strong social bonds. Acoustics is their primary modality to communicate and sense the environment. Research on their echolocation and vocalizations with conspecifics and with humans typically uses visual and tactile systems adapted from research on primates or birds. Such research would benefit from a purely acoustic communication system in which signals flow in both directions simultaneously. We designed and implemented a full duplex system to acoustically interact with cetaceans in the wild, featuring digital echo-suppression. We pilot tested the system in Arctic Norway and achieved an echo suppression of 18 dB leaving room for technical improvements addressed in the discussion. Nevertheless, the system enabled vocal interaction with the underwater acoustic scene by allowing experimenters to listen while producing sounds. We describe our motivations, then present our pilot deployment and give examples of initial explorative attempts to vocally interact with wild orcas and humpback whales
Pain-Related and Negative Semantic Priming Enhances Perceived Pain Intensity
BACKGROUND: Negative affective and pain-related cues, such as pictures or words, have been shown to act as primes and enhance the perceived intensity of subsequent painful events. For pain-related semantic primes, it remains unclear whether this effect depends on negative valence itself or, specifically, on the pain-relatedness of the words
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Clinician and patient perspectives on the barriers and facilitators to physical rehabilitation in intensive care: a qualitative interview study
Data availability statement:
No data are available beyond what is reported in this manuscript and the supplemental files due to participant confidentiality requirements.Objectives: The objective of this study is to explore patient, relative/carer and clinician perceptions of barriers to early physical rehabilitation in intensive care units (ICUs) within an associated group of hospitals in the UK and how they can be overcome.
Design: Qualitative study using semi-structured interviews and thematic framework analysis.
Setting: Four ICUs over three hospital sites in London, UK.
Participants: Former ICU patients or their relatives/carers with personal experience of ICU rehabilitation. ICU clinicians, including doctors, nurses, physiotherapists and occupational therapists, involved in the delivery of physical rehabilitation or decisions over its initiation.
Primary and secondary outcomes measures: Views and experiences on the barriers and facilitators to ICU physical rehabilitation.
Results: Interviews were carried out with 11 former patients, 3 family members and 16 clinicians. The themes generated related to: safety and physiological concerns, patient participation and engagement, clinician experience and knowledge, teamwork, equipment and environment and risks and benefits of rehabilitation in intensive care. The overarching theme for overcoming barriers was a change in working model from ICU clinicians having separate responsibilities (a multidisciplinary approach) to one where all parties have a shared aim of providing patient-centred ICU physical rehabilitation (an interdisciplinary approach).
Conclusions: The results have revealed barriers that can be modified to improve rehabilitation delivery in an ICU. Interdisciplinary working could overcome many of these barriers to optimise recovery from critical illness.Clinical Doctoral Research Fellowship, awarded to HRW, (ICA-CDRF-2015-01-026), supported by the National Institute for Health Research (NIHR) and Health Education England. We acknowledge the support of the NIHR Clinical Research Network and infrastructure support for this research was provided by the NIHR Imperial Biomedical Research Centre (BRC). HRW is supported by the NIHR Imperial BRC
Negative and positive selection of antigen-specific cytotoxic T lymphocytes affected by the α3 domain of MHC I molecules
THE α1 and α2 domains of major histocompatibility complex (MHC) class I molecules function in the binding and presentation of foreign peptides to the T-cell antigen receptor and control both negative and positive selection of the T-cell repertoire. Although the α3 domain of class I is not involved in peptide binding, it does interact with the T-cell accessory molecule, CDS. CDS is important in the selection of T cells as anti-CDS antibody injected into perinatal mice interfers with this process. We previously used a hybrid class I molecule with the α1/α2 domains from L^d and the α3 domain from Q7^b and showed that this molecule binds an L^d-restricted peptide but does not interact with CD8-dependent cytotoxic T lymphocytes. Expression of this molecule in transgenic mice fails to negatively select a subpopulation of anti-L^d cytotoxic T lymphocytes. In addition, positive selection of virus-specific L^d-restricted cytotoxic T lymphocytes does not occur. We conclude that besides the α1/α2 domains of class I, the α3 domain plays an important part in both positive and negative selection of antigen-specific cells
Fluoroquinolones and isoniazid-resistant tuberculosis: implications for the 2018 WHO guidance.
INTRODUCTION: 2018 World Health Organization (WHO) guidelines for the treatment of isoniazid (H)-resistant (Hr) tuberculosis recommend a four-drug regimen: rifampicin (R), ethambutol (E), pyrazinamide (Z) and levofloxacin (Lfx), with or without H ([H]RZE-Lfx). This is used once Hr is known, such that patients complete 6 months of Lfx (≥6[H]RZE-6Lfx). This cohort study assessed the impact of fluoroquinolones (Fq) on treatment effectiveness, accounting for Hr mutations and degree of phenotypic resistance. METHODS: This was a retrospective cohort study of 626 Hr tuberculosis patients notified in London, 2009-2013. Regimens were described and logistic regression undertaken of the association between regimen and negative regimen-specific outcomes (broadly, death due to tuberculosis, treatment failure or disease recurrence). RESULTS: Of 594 individuals with regimen information, 330 (55.6%) were treated with (H)RfZE (Rf=rifamycins) and 211 (35.5%) with (H)RfZE-Fq. The median overall treatment period was 11.9 months and median Z duration 2.1 months. In a univariable logistic regression model comparing (H)RfZE with and without Fqs, there was no difference in the odds of a negative regimen-specific outcome (baseline (H)RfZE, cluster-specific odds ratio 1.05 (95% CI 0.60-1.82), p=0.87; cluster NHS trust). Results varied minimally in a multivariable model. This odds ratio dropped (0.57, 95% CI 0.14-2.28) when Hr genotype was included, but this analysis lacked power (p=0.42). CONCLUSIONS: In a high-income setting, we found a 12-month (H)RfZE regimen with a short Z duration to be similarly effective for Hr tuberculosis with or without a Fq. This regimen may result in fewer adverse events than the WHO recommendations
Grifonin-1: A Small HIV-1 Entry Inhibitor Derived from the Algal Lectin, Griffithsin
Background:
Griffithsin, a 121-residue protein isolated from a red algal Griffithsia sp., binds high mannose N-linked glycans of virus surface glycoproteins with extremely high affinity, a property that allows it to prevent the entry of primary isolates and laboratory strains of T- and M-tropic HIV-1. We used the sequence of a portion of griffithsin's sequence as a design template to create smaller peptides with antiviral and carbohydrate-binding properties.
Methodology/Results:
The new peptides derived from a trio of homologous β-sheet repeats that comprise the motifs responsible for its biological activity. Our most active antiviral peptide, grifonin-1 (GRFN-1), had an EC50 of 190.8±11.0 nM in in vitro TZM-bl assays and an EC50 of 546.6±66.1 nM in p24gag antigen release assays. GRFN-1 showed considerable structural plasticity, assuming different conformations in solvents that differed in polarity and hydrophobicity. Higher concentrations of GRFN-1 formed oligomers, based on intermolecular β-sheet interactions. Like its parent protein, GRFN-1 bound viral glycoproteins gp41 and gp120 via the N-linked glycans on their surface.
Conclusion:
Its substantial antiviral activity and low toxicity in vitro suggest that GRFN-1 and/or its derivatives may have therapeutic potential as topical and/or systemic agents directed against HIV-1
Low-resolution pressure reactivity index and its derived optimal cerebral perfusion pressure in adult traumatic brain injury: a CENTER-TBI study.
BACKGROUND: After traumatic brain injury (TBI), brain tissue can be further damaged when cerebral autoregulation is impaired. Managing cerebral perfusion pressure (CPP) according to computed "optimal CPP" values based on cerebrovascular reactivity indices might contribute to preventing such secondary injuries. In this study, we examined the discriminative value of a low-resolution long pressure reactivity index (LPRx) and its derived "optimal CPP" in comparison to the well-established high-resolution pressure reactivity index (PRx). METHODS: Using the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study dataset, the association of LPRx (correlation between 1-min averages of intracranial pressure and arterial blood pressure over a moving time frame of 20 min) and PRx (correlation between 10-s averages of intracranial pressure and arterial blood pressure over a moving time frame of 5 min) to outcome was assessed and compared using univariate and multivariate regression analysis. "Optimal CPP" values were calculated using a multi-window algorithm that was based on either LPRx or PRx, and their discriminative ability was compared. RESULTS: LPRx and PRx were both significant predictors of mortality in univariate and multivariate regression analysis, but PRx displayed a higher discriminative ability. Similarly, deviations of actual CPP from "optimal CPP" values calculated from each index were significantly associated with outcome in univariate and multivariate analysis. "Optimal CPP" based on PRx, however, trended towards more precise predictions. CONCLUSIONS: LPRx and its derived "optimal CPP" which are based on low-resolution data were significantly associated with outcome after TBI. However, they did not reach the discriminative ability of the high-resolution PRx and its derived "optimal CPP." Nevertheless, LPRx might still be an interesting tool to assess cerebrovascular reactivity in centers without high-resolution signal monitoring. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02210221. First submitted July 29, 2014. First posted August 6, 2014
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