3,250 research outputs found
A metamorphic inorganic framework that can be switched between eight single-crystalline states
The design of highly flexible framework materials requires organic linkers, whereas inorganic materials are more robust but inflexible. Here, by using linkable inorganic rings made up of tungsten oxide (P8W48O184) building blocks, we synthesized an inorganic single crystal material that can undergo at least eight different crystal-to-crystal transformations, with gigantic crystal volume contraction and expansion changes ranging from −2,170 to +1,720 Å3 with no reduction in crystallinity. Not only does this material undergo the largest single crystal-to-single crystal volume transformation thus far reported (to the best of our knowledge), the system also shows conformational flexibility while maintaining robustness over several cycles in the reversible uptake and release of guest molecules switching the crystal between different metamorphic states. This material combines the robustness of inorganic materials with the flexibility of organic frameworks, thereby challenging the notion that flexible materials with robustness are mutually exclusive
Dynamics of viscous amphiphilic films supported by elastic solid substrates
The dynamics of amphiphilic films deposited on a solid surface is analyzed
for the case when shear oscillations of the solid surface are excited. The two
cases of surface- and bulk shear waves are studied with film exposed to gas or
to a liquid. By solving the corresponding dispersion equation and the wave
equation while maintaining the energy balance we are able to connect the
surface density and the shear viscocity of a fluid amphiphilic overlayer with
experimentally accessible damping coefficients, phase velocity, dissipation
factor and resonant frequency shifts of shear waves.Comment: 19 pages, latex, 3 figures in eps-forma
Stimulation of translation by human Unr requires cold shock domains 2 and 4, and correlates with poly(A) binding protein interaction
The RNA binding protein Unr, which contains five cold shock domains, has several specific roles in post-transcriptional control of gene expression. It can act as an activator or inhibitor of translation initiation, promote mRNA turnover, or stabilise mRNA. Its role depends on the mRNA and other proteins to which it binds, which includes cytoplasmic poly(A) binding protein 1 (PABP1). Since PABP1 binds to all polyadenylated mRNAs, and is involved in translation initiation by interaction with eukaryotic translation initiation factor 4G (eIF4G), we investigated whether Unr has a general role in translational control. We found that Unr strongly stimulates translation in vitro, and mutation of cold shock domains 2 or 4 inhibited its translation activity. The ability of Unr and its mutants to stimulate translation correlated with its ability to bind RNA, and to interact with PABP1. We found that Unr stimulated the binding of PABP1 to mRNA, and that Unr was required for the stable interaction of PABP1 and eIF4G in cells. siRNA-mediated knockdown of Unr reduced the overall level of cellular translation in cells, as well as that of cap-dependent and IRES-dependent reporters. These data describe a novel role for Unr in regulating cellular gene expression
The Period Changes of the Cepheid RT Aurigae
Observations of the light curve for the 3.7-day Cepheid RT Aur both before
and since 1980 indicate that the variable is undergoing an overall period
increase, amounting to +0.082 +-0.012 s/yr, rather than a period decrease, as
implied by all observations prior to 1980. Superposed on the star's O-C
variations is a sinusoidal trend that cannot be attributed to random
fluctuations in pulsation period. Rather, it appears to arise from light travel
time effects in a binary system. The derived orbital period for the system is P
= 26,429 +-89 days (72.36 +-0.24 years). The inferred orbital parameters from
the O-C residuals differ from those indicated by existing radial velocity data.
The latter imply the most reasonable results, namely a1 sin i = 9.09 (+-1.81) x
10^8 km and a minimum secondary mass of M2 = 1.15 +-0.25 Msun. Continued
monitoring of the brightness and radial velocity changes in the Cepheid are
necessary to confirm the long-term trend and to provide data for a proper
spectroscopic solution to the orbit.Comment: Accepted for publication in PASP (November 2007
Barriers and facilitators to self-management of asthma in adolescents:an interview study to inform development of a novel intervention
BACKGROUND AND OBJECTIVE: Despite literature that spans twenty years describing the barriers to asthma self-management in adolescents, successful, clinically-based interventions to address this important issue are lacking. Given the limitations of some of the previous studies, we conducted a study that aimed to gain a broader insight into barriers and facilitators to self-management of asthma by adolescents, not just adherence to treatment, and triangulated their views with those of their parents and healthcare professionals. METHODS: Focus groups and interviews were conducted separately for 28 adolescents with asthma aged 12-18 years, 14 healthcare professionals, and 12 parents. Focus groups and interviews were audio-recorded and transcripts from each participant group were analysed separately using inductive thematic analysis. We triangulated the three perspectives by comparing themes that had emerged from each analysis. RESULTS: Adolescents', parents', and healthcare professionals' views were summarised into ten related themes that included forgetting and routines, knowledge, embarrassment and confidence, communication with healthcare professionals, triggers, support at school, apathy, and taking responsibility. We found that adolescents, parents and healthcare professionals raised similar barriers and facilitators to self-management and our results provide further validation for previous studies. CONCLUSION AND CLINICAL RELEVANCE: Our study highlights that healthcare professionals may need to consider a range of psychological and contextual issues influencing adolescents' ability to effectively self-manage their asthma, in particular, how they implement treatment routines and the understanding that adolescents have of their condition and treatments. Crucially, healthcare professionals need to consider how this information is communicated and ensure they facilitate open, inclusive, two-way consultations. From this more comprehensive understanding, we have developed interventional strategies that healthcare professionals can utilise to empower adolescents to improve their asthma self-management. This article is protected by copyright. All rights reserved
Body temperature, activity patterns and hunting in free-living cheetah : biologging reveals new insights
As one of the few felids that is predominantly diurnal, cheetahs (Acinonyx jubatus) can be exposed to high heat loads in their natural habitat. Little is known about long‐term patterns of body temperature and activity (including hunting) in cheetahs because long‐term concurrent measurements of body temperature and activity have never been reported for cheetahs, or, indeed, for any free‐living felid. We report here body temperature and locomotor activity measured with implanted data loggers over 7 months in 5 free‐living cheetahs in Namibia. Air temperature ranged from a maximum of 39 °C in summer to −2 °C in winter. Cheetahs had higher (∼0.4 °C) maximum 24‐h body temperatures, later acrophase (∼1 h), with larger fluctuations in the range of the 24‐h body temperature rhythm (approximately 0.4 °C) during a hot‐dry period than during a cool‐dry period, but maintained homeothermy irrespective of the climatic conditions. As ambient temperatures increased, the cheetahs shifted from a diurnal to a crepuscular activity pattern, with reduced activity between 900 and 1500 hours and increased nocturnal activity. The timing of hunts followed the general pattern of activity; the cheetahs hunted when they were on the move. Cheetahs hunted if an opportunity presented itself; on occasion they hunted in the midday heat or in total darkness (new moon). Biologging revealed insights into cheetah biology that are not accessible by traditional observer‐based techniques.Supplementary Material: Table S1 Prey identified after 38 successful hunts.
Figure S1 An original record of 10‐min recordings of body temperature from a single free‐living female cheetah (female 1, panel B) and the prevailing black globe temperature recorded at a nearby weather station (panel A) over the 7‐month study period (October to May).The National Research Foundation of South Africa and a Carnegie Large Research Grant.https://onlinelibrary.wiley.com/journal/17494877hj2020Paraclinical Science
Measurements of Deuteron Photodisintegration up to 4.0 GeV
The first measurements of the differential cross section for the d(gamma,p)n
reaction up to 4.0 GeV were performed at Continuous Electron Beam Accelerator
Facility (CEBAF) at Jefferson Lab. We report the cross sections at the proton
center-of-mass angles of 36, 52, 69 and 89 degrees. These results are in
reasonable agreement with previous measurements at lower energy. The 89 and 69
degree data show constituent-counting-rule behavior up to 4.0 GeV photon
energy. The 36 and 52 degree data disagree with the counting rule behavior. The
quantum chromodynamics (QCD) model of nuclear reactions involving reduced
amplitudes disagrees with the present data.Comment: 5 pages (REVTeX), 1 figure (postscript
How can we objectively categorise partnership type? A novel classification of population survey data to inform epidemiological research and clinical practice
Abstract: Background Partnership type is a determinant of STI risk; yet, it is poorly and inconsistently recorded in clinical practice and research. We identify a novel, empirical-based categorisation of partnership type, and examine whether reporting STI diagnoses varies by the resulting typologies.
Methods: Analyses of probability survey data collected from 15 162 people aged 16–74 who participated in Britain's third National Survey of Sexual Attitudes and Lifestyles were undertaken during 2010–2012. Computer-assisted self-interviews asked about participants' ≤3 most recent partners (N=14 322 partners/past year). Analysis of variance and regression tested for differences in partnership duration and perceived likelihood of sex again across 21 ‘partnership progression types’ (PPTs) derived from relationship status at first and most recent sex. Multivariable regression examined the association between reporting STI diagnoses and partnership type(s) net of age and reported partner numbers (all past year).
Results: The 21 PPTs were grouped into four summary types: ‘cohabiting’, ‘now steady’, ‘casual’ and ‘ex-steady’ according to the average duration and likelihood of sex again. 11 combinations of these summary types accounted for 94.5% of all men; 13 combinations accounted for 96.9% of all women. Reporting STI diagnoses varied by partnership-type combination, including after adjusting for age and partner numbers, for example, adjusted OR: 6.03 (95% CI 2.01 to 18.1) for men with two ‘casual’ and one ‘now steady’ partners versus men with one ‘cohabiting’ partner.
Conclusions: This typology provides an objective method for measuring partnership type and demonstrates its importance in understanding STI risk, net of partner numbers. Epidemiological research and clinical practice should use these methods and results to maximise individual and public health benefit
Cognitive behavioural therapy for adults with dissociative seizures (CODES): a pragmatic, multicentre, randomised controlled trial.
BACKGROUND: Dissociative seizures are paroxysmal events resembling epilepsy or syncope with characteristic features that allow them to be distinguished from other medical conditions. We aimed to compare the effectiveness of cognitive behavioural therapy (CBT) plus standardised medical care with standardised medical care alone for the reduction of dissociative seizure frequency. METHODS: In this pragmatic, parallel-arm, multicentre randomised controlled trial, we initially recruited participants at 27 neurology or epilepsy services in England, Scotland, and Wales. Adults (≥18 years) who had dissociative seizures in the previous 8 weeks and no epileptic seizures in the previous 12 months were subsequently randomly assigned (1:1) from 17 liaison or neuropsychiatry services following psychiatric assessment, to receive standardised medical care or CBT plus standardised medical care, using a web-based system. Randomisation was stratified by neuropsychiatry or liaison psychiatry recruitment site. The trial manager, chief investigator, all treating clinicians, and patients were aware of treatment allocation, but outcome data collectors and trial statisticians were unaware of treatment allocation. Patients were followed up 6 months and 12 months after randomisation. The primary outcome was monthly dissociative seizure frequency (ie, frequency in the previous 4 weeks) assessed at 12 months. Secondary outcomes assessed at 12 months were: seizure severity (intensity) and bothersomeness; longest period of seizure freedom in the previous 6 months; complete seizure freedom in the previous 3 months; a greater than 50% reduction in seizure frequency relative to baseline; changes in dissociative seizures (rated by others); health-related quality of life; psychosocial functioning; psychiatric symptoms, psychological distress, and somatic symptom burden; and clinical impression of improvement and satisfaction. p values and statistical significance for outcomes were reported without correction for multiple comparisons as per our protocol. Primary and secondary outcomes were assessed in the intention-to-treat population with multiple imputation for missing observations. This trial is registered with the International Standard Randomised Controlled Trial registry, ISRCTN05681227, and ClinicalTrials.gov, NCT02325544. FINDINGS: Between Jan 16, 2015, and May 31, 2017, we randomly assigned 368 patients to receive CBT plus standardised medical care (n=186) or standardised medical care alone (n=182); of whom 313 had primary outcome data at 12 months (156 [84%] of 186 patients in the CBT plus standardised medical care group and 157 [86%] of 182 patients in the standardised medical care group). At 12 months, no significant difference in monthly dissociative seizure frequency was identified between the groups (median 4 seizures [IQR 0-20] in the CBT plus standardised medical care group vs 7 seizures [1-35] in the standardised medical care group; estimated incidence rate ratio [IRR] 0·78 [95% CI 0·56-1·09]; p=0·144). Dissociative seizures were rated as less bothersome in the CBT plus standardised medical care group than the standardised medical care group (estimated mean difference -0·53 [95% CI -0·97 to -0·08]; p=0·020). The CBT plus standardised medical care group had a longer period of dissociative seizure freedom in the previous 6 months (estimated IRR 1·64 [95% CI 1·22 to 2·20]; p=0·001), reported better health-related quality of life on the EuroQoL-5 Dimensions-5 Level Health Today visual analogue scale (estimated mean difference 6·16 [95% CI 1·48 to 10·84]; p=0·010), less impairment in psychosocial functioning on the Work and Social Adjustment Scale (estimated mean difference -4·12 [95% CI -6·35 to -1·89]; p<0·001), less overall psychological distress than the standardised medical care group on the Clinical Outcomes in Routine Evaluation-10 scale (estimated mean difference -1·65 [95% CI -2·96 to -0·35]; p=0·013), and fewer somatic symptoms on the modified Patient Health Questionnaire-15 scale (estimated mean difference -1·67 [95% CI -2·90 to -0·44]; p=0·008). Clinical improvement at 12 months was greater in the CBT plus standardised medical care group than the standardised medical care alone group as reported by patients (estimated mean difference 0·66 [95% CI 0·26 to 1·04]; p=0·001) and by clinicians (estimated mean difference 0·47 [95% CI 0·21 to 0·73]; p<0·001), and the CBT plus standardised medical care group had greater satisfaction with treatment than did the standardised medical care group (estimated mean difference 0·90 [95% CI 0·48 to 1·31]; p<0·001). No significant differences in patient-reported seizure severity (estimated mean difference -0·11 [95% CI -0·50 to 0·29]; p=0·593) or seizure freedom in the last 3 months of the study (estimated odds ratio [OR] 1·77 [95% CI 0·93 to 3·37]; p=0·083) were identified between the groups. Furthermore, no significant differences were identified in the proportion of patients who had a more than 50% reduction in dissociative seizure frequency compared with baseline (OR 1·27 [95% CI 0·80 to 2·02]; p=0·313). Additionally, the 12-item Short Form survey-version 2 scores (estimated mean difference for the Physical Component Summary score 1·78 [95% CI -0·37 to 3·92]; p=0·105; estimated mean difference for the Mental Component Summary score 2·22 [95% CI -0·30 to 4·75]; p=0·084), the Generalised Anxiety Disorder-7 scale score (estimated mean difference -1·09 [95% CI -2·27 to 0·09]; p=0·069), and the Patient Health Questionnaire-9 scale depression score (estimated mean difference -1·10 [95% CI -2·41 to 0·21]; p=0·099) did not differ significantly between groups. Changes in dissociative seizures (rated by others) could not be assessed due to insufficient data. During the 12-month period, the number of adverse events was similar between the groups: 57 (31%) of 186 participants in the CBT plus standardised medical care group reported 97 adverse events and 53 (29%) of 182 participants in the standardised medical care group reported 79 adverse events. INTERPRETATION: CBT plus standardised medical care had no statistically significant advantage compared with standardised medical care alone for the reduction of monthly seizures. However, improvements were observed in a number of clinically relevant secondary outcomes following CBT plus standardised medical care when compared with standardised medical care alone. Thus, adults with dissociative seizures might benefit from the addition of dissociative seizure-specific CBT to specialist care from neurologists and psychiatrists. Future work is needed to identify patients who would benefit most from a dissociative seizure-specific CBT approach. FUNDING: National Institute for Health Research, Health Technology Assessment programme
The Structure of the Homunculus. II. Modeling the physical conditions in Eta Car's molecular shell
We present models that reproduce the observed double-shell structure of the
Homunculus Nebula around eta Carinae, including the stratification of infrared
H2 and [FeII] emission seen in data obtained with the Phoenix spectrograph on
Gemini South, as well as the corresponding stratified grain temperature seen in
thermal-infrared data. Tuning the model to match the observed shell thickness
allows us to determine the threshold density which permits survival of H2. An
average hydrogen density of n_H=(0.5-1)x10^7 cm-3 in the outer zone is required
to allow H2 to exist at all latitudes in the nebula, and for Fe+ to recombine.
This gives independent confirmation of the very large mass of the Homunculus,
indicating a total of roughly 15--35 Msun (although we note reasons why the
lower end of this range is favored). At the interface between the atomic and
molecular zones, we predict a sharp drop in the dust temperature, in agreement
with the bimodal dust color temperatures observed in the two zones. In the
outer molecular shell, the dust temperature drops to nearly the blackbody
temperature, and becomes independent of grain size because of self-shielding at
shorter UV wavelengths and increased heating at longer wavelengths. This
relaxes constraints on large grain sizes suggested by near-blackbody color
temperatures. Finally, from the strength of infrared [FeII] emission in the
inner shell we find that the gas-phase Fe abundance is roughly solar. This is
astonishing in such a dusty object, where one normally expects gaseous iron to
be depleted by two orders of magnitude.Comment: 18 pages, 5 figures. Accepted by Ap
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