601 research outputs found
It takes three to tango: The length of the oligothiophene chain determines the nature of the long‐lived excited state and the resulting photocytotoxicity of a ruthenium(II) Photodrug
Abstract TLD1433 is the first Ru(II) complex to be tested as a photodynamic therapy agent in a clinical trial. In this contribution we study TLD1433 in the context of structurally‐related Ru(II)‐imidozo[4,5‐f][1,10]phenanthroline (ip) complexes appended with thiophene rings to decipher the unique photophysical properties which are associated with increasing oligothiophene chain length. Substitution of the ip ligand with ter‐ or quaterthiophene changes the nature of the long‐lived triplet state from metal‐to‐ligand charge‐transfer to 3 ππ* character. The addition of the third thiophene thus presents a critical juncture which not only determines the photophysics of the complex but most importantly its capacity for 1 O 2 generation and hence the potential of the complex to be used as a photocytotoxic agent
Imaging in Vascular Access
This review examines four imaging modalities; ultrasound (US), digital subtraction angiography (DSA), magnetic resonance imaging (MRI) and computed tomography (CT), that have common or potential applications in vascular access (VA). The four modalities are reviewed under their primary uses, techniques, advantages and disadvantages, and future directions that are specific to VA. Currently, US is the most commonly used modality in VA because it is cheaper (relative to other modalities), accessible, non-ionising, and does not require the use of contrast agents. DSA is predominantly only performed when an intervention is indicated. MRI is limited by its cost and the time required for image acquisition that mainly confines it to the realm of research where high resolution is required. CT’s short acquisition times and high resolution make it useful as a problem-solving tool in complex cases, although accessibility can be an issue. All four imaging modalities have advantages and disadvantages that limit their use in this particular patient cohort. Current imaging in VA comprises an integrated approach with each modality providing particular uses dependent on their capabilities. MRI and CT, which currently have limited use, may have increasingly important future roles in complex cases where detailed analysis is required
Cross-sectional survey of users of internet depression communities
Background: Internet-based depression communities provide a forum for individuals to
communicate and share information and ideas. There has been little research into the health status
and other characteristics of users of these communities.
Methods: Online cross-sectional survey of Internet depression communities to identify depressive
morbidity among users of Internet depression communities in six European countries; to
investigate whether users were in contact with health services and receiving treatment; and to
identify user perceived effects of the communities.
Results: Major depression was highly prevalent among respondents (varying by country from 40%
to 64%). Forty-nine percent of users meeting criteria for major depression were not receiving
treatment, and 35% had no consultation with health services in the previous year. Thirty-six
percent of repeat community users who had consulted a health professional in the previous year
felt that the Internet community had been an important factor in deciding to seek professional help.
Conclusions: There are high levels of untreated and undiagnosed depression in users of Internet
depression communities. This group represents a target for intervention. Internet communities can
provide information and support for stigmatizing conditions that inhibit more traditional modes of
information seeking
Local light-ray rotation
We present a sheet structure that rotates the local ray direction through an
arbitrary angle around the sheet normal. The sheet structure consists of two
parallel Dove-prism sheets, each of which flips one component of the local
direction of transmitted light rays. Together, the two sheets rotate
transmitted light rays around the sheet normal. We show that the direction
under which a point light source is seen is given by a Mobius transform. We
illustrate some of the properties with movies calculated by ray-tracing
software.Comment: 9 pages, 6 figure
Utility of the FebriDx point-of-care assay in supporting a triage algorithm for medical admissions with possible COVID-19: an observational cohort study
Objective: To evaluate a triage algorithm used to identify and isolate patients with suspected COVID-19 among medical patients needing admission to hospital using simple clinical criteria and the FebriDx assay.
Design:: Retrospective observational cohort.
Setting Large acute National Health Service hospital in London, UK.
Participants: All medical admissions from the emergency department between 10 August 2020 and 4 November 2020 with a valid SARS-CoV-2 RT-PCR result.
Interventions: Medical admissions were triaged as likely, possible or unlikely COVID-19 based on clinical criteria. Patients triaged as possible COVID-19 underwent FebriDx lateral flow assay on capillary blood, and those positive for myxovirus resistance protein A (a host response protein) were managed as likely COVID-19.
Primary outcome measures: Diagnostic accuracy (sensitivity, specificity and predictive values) of the algorithm and the FebriDx assay using SARS-CoV-2 RT-PCR from nasopharyngeal swabs as the reference standard.
Results: 4.0% (136) of 3443 medical admissions had RT-PCR confirmed COVID-19. Prevalence of COVID-19 was 46% (80/175) in those triaged as likely, 4.1% (50/1225) in possible and 0.3% (6/2033) in unlikely COVID-19. Using a SARS-CoV-2 RT-PCR reference standard, clinical triage had sensitivity of 96% (95% CI 91% to 98%) and specificity of 61.5% (95% CI 59.8% to 63.1%), while the triage algorithm including FebriDx had sensitivity of 93% (95% CI 87% to 96%) and specificity of 86.4% (95% CI 85.2% to 87.5%). While 2033 patients were deemed not to require isolation using clinical criteria alone, the addition of FebriDx to clinical triage allowed a further 826 patients to be released from isolation, reducing the need for isolation rooms by 9.5 per day, 95% CI 8.9 to 10.2. Ten patients missed by the algorithm had mild or asymptomatic COVID-19.
Conclusions: A triage algorithm including the FebriDx assay had good sensitivity and was useful to ‘rule-out’ COVID-19 among medical admissions to hospital
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Intracellular Photophysics of an Osmium Complex bearing an Oligothiophene Extended Ligand
This contribution describes the excited-state properties of an Osmium-complex when taken up into human cells. The complex 1 [Os(bpy)2(IP-4T)](PF6)2 with bpy=2,2′-bipyridine and IP-4T=2-{5′-[3′,4′-diethyl-(2,2′-bithien-5-yl)]-3,4-diethyl-2,2′-bithiophene}imidazo[4,5-f][1,10]phenanthroline) can be discussed as a candidate for photodynamic therapy in the biological red/NIR window. The complex is taken up by MCF7 cells and localizes rather homogeneously within in the cytoplasm. To detail the sub-ns photophysics of 1, comparative transient absorption measurements were carried out in different solvents to derive a model of the photoinduced processes. Key to rationalize the excited-state relaxation is a long-lived 3ILCT state associated with the oligothiophene chain. This model was then tested with the complex internalized into MCF7 cells, since the intracellular environment has long been suspected to take big influence on the excited state properties. In our study of 1 in cells, we were able to show that, though the overall model remained the same, the excited-state dynamics are affected strongly by the intracellular environment. Our study represents the first in depth correlation towards ex-vivo and in vivo ultrafast spectroscopy for a possible photodrug. © 2020 The Authors. Published by Wiley-VCH Gmb
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