2,046 research outputs found
Adolescentsâ and young adultsâ online risk taking : the role of gist and verbatim representations
Young people are exposed to and engage in online risky activities, such as disclosing personal information and making unknown friends online. Little research has examined the psychological mechanisms underlying young peopleâs online risk taking. Drawing on Fuzzy Trace Theory, we examined developmental differences in adolescentsâ and young adultsâ online risk taking and assessed whether differential reliance on gist representations (based on vague, intuitive knowledge) or verbatim representations (based on specific, factual knowledge) could explain online risk taking. One hundred and twenty two adolescents (ages 13-17) and 172 young adults (ages 18-24) were asked about their past online risk taking behaviour, intentions to engage in future risky online behaviour, and gist and verbatim representations. Adolescents had significantly higher intentions to take online risks than young adults. Past risky online behaviours were positively associated with future intentions to take online risks for adolescents and negatively for young adults. Gist representations about risk negatively correlated with intentions to take risks online in both age groups, while verbatim representations positively correlated with online risk intentions, particularly among adolescents. Our results provide novel insights about the underlying mechanisms involved in adolescent and young adultsâ online risk taking, suggesting the need to tailor the representation of online risk information to different age groups
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Conformational modulation of sequence recognition in synthetic macromolecules
The different triplet sequences in high molecular weight aromatic copolyimides comprising pyromellitimide units ("I") flanked by either ether-ketone ("K") or ether-sulfone residues ("S") show different binding strengths for pyrene-based tweezer-molecules. Such molecules bind primarily to the diimide unit through complementary Ï-Ï-stacking and hydrogen bonding. However, as shown by the magnitudes of 1H NMR complexation shifts and tweezer-polymer binding constants, the triplet "SIS" binds tweezer-molecules more strongly than "KIS" which in turn bind such molecules more strongly than "KIK". Computational models for tweezer-polymer binding, together with single-crystal X-ray analyses of tweezer-complexes with macrocyclic ether-imides, reveal that the variations in binding strength between the different triplet sequences arise from the different conformational preferences of aromatic rings at diarylketone and diarylsulfone linkages. These preferences determine whether or not chain-folding and secondary ÏâÏ-stacking occurs between the arms of the tweezermolecule and the 4,4'-biphenylene units which flank the central diimide residue
The build-up of the colour-magnitude relation in galaxy clusters since z~0.8
Using galaxy clusters from the ESO Distant Cluster Survey, we study how the
distribution of galaxies along the colour-magnitude relation has evolved since
z~0.8. While red-sequence galaxies in all these clusters are well described by
an old, passively evolving population, we confirm our previous finding of a
significant evolution in their luminosity distribution as a function of
redshift. When compared to galaxy clusters in the local Universe, the high
redshift EDisCS clusters exhibit a significant "deficit" of faint red galaxies.
Combining clusters in three different redshift bins, and defining as `faint'
all galaxies in the range 0.4 > L/L* > 0.1, we find a clear decrease in the
luminous-to-faint ratio of red galaxies from z~0.8 to z~0.4. The amount of such
a decrease appears to be in qualitative agreement with predictions of a model
where the blue bright galaxies that populate the colour-magnitude diagram of
high redshift clusters, have their star formation suppressed by the hostile
cluster environment. Although model results need to be interpreted with
caution, our findings clearly indicate that the red-sequence population of
high-redshift clusters does not contain all progenitors of nearby red-sequence
cluster galaxies. A significant fraction of these must have moved onto the
red-sequence below z~0.8.Comment: 15 pages, 10 figures, accepted for publication in MNRA
Recreating daylight for readability assessments of in-vehicle displays
This paper describes the early stages of research into defining daylight scenarios encountered by vehicles and outlining which are the worst-case situations with respect to display readability. The main objective of the research is to design a facility capable of recreating a wide range of daylight scenarios to perform controlled, repeatable and reproducible readability assessments within automotive vehicles. This will be achieved through sky luminance mapping, display readability assessments under real skies and investigations into daylighting technologies
The relation between star formation, morphology and local density in high redshift clusters and groups
We investigate how the [OII] properties and the morphologies of galaxies in
clusters and groups at z=0.4-0.8 depend on projected local galaxy density, and
compare with the field at similar redshifts and clusters at low-z. In both
nearby and distant clusters, higher-density regions contain proportionally
fewer star-forming galaxies, and the average [OII] equivalent width of
star-forming galaxies is independent of local density. However, in distant
clusters the average current star formation rate (SFR) in star-forming galaxies
seems to peak at densities ~15-40 galaxies Mpc^{-2}. At odds with low-z
results, at high-z the relation between star-forming fraction and local density
varies from high- to low-mass clusters. Overall, our results suggest that at
high-z the current star formation (SF) activity in star-forming galaxies does
not depend strongly on global or local environment, though the possible SFR
peak seems at odds with this conclusion. We find that the cluster SFR
normalized by cluster mass anticorrelates with mass and correlates with the
star-forming fraction. These trends can be understood given a) that the average
star-forming galaxy forms about 1 Msun/yr in all clusters; b) that the total
number of galaxies scales with cluster mass and c) the dependence of
star-forming fraction on cluster mass. We present the morphology-density (MD)
relation for our z=0.4-0.8 clusters, and uncover that the decline of the spiral
fraction with density is entirely driven by galaxies of types Sc or later. For
galaxies of a given Hubble type, we see no evidence that SF properties depend
on local environment. In contrast with recent findings at low-z, in our distant
clusters the SF-density relation and the MD-relation are equivalent, suggesting
that neither of the two is more fundamental than the other.(abr.)Comment: 21 pages, 14 figures, accepted for publication in Ap
Uptake of synthetic low density lipoprotein by leukemic stem cells â a potential stem cell targeted drug delivery strategy
Chronic Myeloid Leukemia (CML) stem/progenitor cells, which over-express Bcr-Abl, respond to imatinib by a reversible block in proliferation without significant apoptosis. As a result, patients are unlikely to be cured owing to the persistence of leukemic quiescent stem cells (QSC) capable of initiating relapse. Previously, we have reported that intracellular levels of imatinib in primary primitive CML cells (CD34<sup>+</sup>38<sup>lo/â</sup>), are significantly lower than in CML progenitor cells (total CD34<sup>+</sup>) and leukemic cell lines. The aim of this study was to determine if potentially sub-therapeutic intracellular drug concentrations in persistent leukemic QSC may be overcome by targeted drug delivery using synthetic Low Density Lipoprotein (sLDL) particles. As a first step towards this goal, however, the extent of uptake of sLDL by leukemic cell lines and CML patient stem/progenitor cells was investigated. Results with non-drug loaded particles have shown an increased and preferential uptake of sLDL by Bcr-Abl positive cell lines in comparison to Bcr-Abl negative. Furthermore, CML CD34<sup>+</sup> and primitive CD34<sup>+</sup>38<sup>lo/â</sup> cells accumulated significantly higher levels of sLDL when compared with non-CML CD34<sup>+</sup> cells. Thus, drug-loading the sLDL nanoparticles could potentially enhance intracellular drug concentrations in primitive CML cells and thus aid their eradication
Post-mortem culture of Balamuthia mandrillaris from the brain and cerebrospinal fluid of a case of granulomatous amoebic meningoencephalitis, using human brain microvascular endothelial cells
The first isolation in the UK of Balamuthia mandrillaris amoebae from a fatal case of granulomatous amoebic meningoencephalitis is reported. Using primary cultures of human brain microvascular endothelial cells (HBMECs), amoebae were isolated from the brain and cerebrospinal fluid (CSF). The cultures showed a cytopathic effect at 20â28 days, but morphologically identifiable B. mandrillaris amoebae were seen in cleared plaques in subcultures at 45 days. The identification of the organism was later confirmed using PCR on Chelex-treated extracts. Serum taken while the patient was still alive reacted strongly with slide antigen prepared from cultures of the post-mortem isolate, and also with those from a baboon B. mandrillaris strain at 1 : 10 000 in indirect immunofluorescence, but with Acanthamoeba castellanii (Neff) at 1 : 160, supporting B. mandrillaris to be the causative agent. If the presence of amoebae in the post-mortem CSF reflects the condition in life, PCR studies on CSF and on biopsies of cutaneous lesions may also be a valuable tool. The role of HBMECs in understanding the interactions of B. mandrillaris with the bloodâbrain barrier is discussed
Antidepressants for pain management in adults with chronic pain:a network meta-analysis
Background: Chronic pain is common in adults, and often has a detrimental impact upon physical ability, well-being, and quality of life. Previous reviews have shown that certain antidepressants may be effective in reducing pain with some benefit in improving patientsâ global impression of change for certain chronic pain conditions. However, there has not been a network meta-analysis (NMA) examining all antidepressants across all chronic pain conditions. Objectives: To assess the comparative efficacy and safety of antidepressants for adults with chronic pain (except headache). Search methods: We searched CENTRAL, MEDLINE, Embase, CINAHL, LILACS, AMED and PsycINFO databases, and clinical trials registries, for randomised controlled trials (RCTs) of antidepressants for chronic pain conditions in January 2022. Selection criteria: We included RCTs that examined antidepressants for chronic pain against any comparator. If the comparator was placebo, another medication, another antidepressant, or the same antidepressant at different doses, then we required the study to be double-blind. We included RCTs with active comparators that were unable to be double-blinded (e.g. psychotherapy) but rated them as high risk of bias. We excluded RCTs where the follow-up was less than two weeks and those with fewer than 10 participants in each arm. Data collection and analysis: Two review authors separately screened, data extracted, and judged risk of bias. We synthesised the data using Bayesian NMA and pairwise meta-analyses for each outcome and ranked the antidepressants in terms of their effectiveness using the surface under the cumulative ranking curve (SUCRA). We primarily used Confidence in Meta-Analysis (CINeMA) and Risk of Bias due to Missing Evidence in Network meta-analysis (ROB-MEN) to assess the certainty of the evidence. Where it was not possible to use CINeMA and ROB-MEN due to the complexity of the networks, we used GRADE to assess the certainty of the evidence. Our primary outcomes were substantial (50%) pain relief, pain intensity, mood, and adverse events. Our secondary outcomes were moderate pain relief (30%), physical function, sleep, quality of life, Patient Global Impression of Change (PGIC), serious adverse events, and withdrawal. Main results: This review and NMA included 176 studies with a total of 28,664 participants. The majority of studies were placebo-controlled (83), and parallelâarmed (141). The most common pain conditions examined were fibromyalgia (59 studies); neuropathic pain (49 studies) and musculoskeletal pain (40 studies). The average length of RCTs was 10 weeks. Seven studies provided no useable data and were omitted from the NMA. The majority of studies measured short-term outcomes only and excluded people with low mood and other mental health conditions. Across efficacy outcomes, duloxetine was consistently the highest-ranked antidepressant with moderate- to high-certainty evidence. In duloxetine studies, standard dose was equally efficacious as high dose for the majority of outcomes. Milnacipran was often ranked as the next most efficacious antidepressant, although the certainty of evidence was lower than that of duloxetine. There was insufficient evidence to draw robust conclusions for the efficacy and safety of any other antidepressant for chronic pain. Primary efficacy outcomes. Duloxetine standard dose (60 mg) showed a small to moderate effect for substantial pain relief (odds ratio (OR) 1.91, 95% confidence interval (CI) 1.69 to 2.17; 16 studies, 4490 participants; moderate-certainty evidence) and continuous pain intensity (standardised mean difference (SMD) â0.31, 95% CI â0.39 to â0.24; 18 studies, 4959 participants; moderate-certainty evidence). For pain intensity, milnacipran standard dose (100 mg) also showed a small effect (SMD â0.22, 95% CI â0.39 to 0.06; 4 studies, 1866 participants; moderate-certainty evidence). Mirtazapine (30 mg) had a moderate effect on mood (SMD â0.5, 95% CI â0.78 to â0.22; 1 study, 406 participants; low-certainty evidence), while duloxetine showed a small effect (SMD â0.16, 95% CI â0.22 to â0.1; 26 studies, 7952 participants; moderate-certainty evidence); however it is important to note that most studies excluded participants with mental health conditions, and so average anxiety and depression scores tended to be in the 'normal' or 'subclinical' ranges at baseline already. Secondary efficacy outcomes. Across all secondary efficacy outcomes (moderate pain relief, physical function, sleep, quality of life, and PGIC), duloxetine and milnacipran were the highest-ranked antidepressants with moderate-certainty evidence, although effects were small. For both duloxetine and milnacipran, standard doses were as efficacious as high doses. Safety. There was very low-certainty evidence for all safety outcomes (adverse events, serious adverse events, and withdrawal) across all antidepressants. We cannot draw any reliable conclusions from the NMAs for these outcomes. Authors' conclusions: Our review and NMAs show that despite studies investigating 25 different antidepressants, the only antidepressant we are certain about for the treatment of chronic pain is duloxetine. Duloxetine was moderately efficacious across all outcomes at standard dose. There is also promising evidence for milnacipran, although further high-quality research is needed to be confident in these conclusions. Evidence for all other antidepressants was low certainty. As RCTs excluded people with low mood, we were unable to establish the effects of antidepressants for people with chronic pain and depression. There is currently no reliable evidence for the long-term efficacy of any antidepressant, and no reliable evidence for the safety of antidepressants for chronic pain at any time point.</p
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