9,024 research outputs found
High-mobility solution-processed copper phthalocyanine-based organic field-effect transistors
© 2011 National Institute for Materials ScienceSolution-processed films of 1,4,8,11,15,18,22,25-octakis(hexyl) copper phthalocyanine (CuPc6) were utilized as an active semiconducting layer in the fabrication of organic field-effect transistors (OFETs) in the bottom-gate configurations using chemical vapour deposited silicon dioxide (SiO2) as gate dielectrics. The surface treatment of the gate dielectric with a self-assembled monolayer of octadecyltrichlorosilane (OTS) resulted in values of 4×10−2 cm2 V−1 s−1 and 106 for saturation mobility and on/off current ratio, respectively. This improvement was accompanied by a shift in the threshold voltage from 3V for untreated devices to −2V for OTS treated devices. The trap density at the interface between the gate dielectric and semiconductor decreased by about one order of magnitude after the surface treatment. The transistors with the OTS treated gate dielectrics were more stable over a 30-day period in air than untreated ones.Technology Strategy Board, UK (Project No: TP/6/EPH/6/S/K2536J)
The effect of habitual exercise on respiratory-muscle function in older adults
Older adults' participation in habitual exercise might be affected by alterations to respiratory mechanics such as decreased respiratory-muscle strength. This reduction can cause a decrease in efficiency of the ventilatory pump, potentially compromising exercise participation. This research examined the role of habitual exercise in respiratory-muscle function and the associated implications for exercise performance. Seventy-two healthy older adults (36 men, 64.9 ± 8.6 years, 177.2 ± 8.4 cm, 82.5 ± 11.9 kg; 36 women, 64.9 ± 9.5 years, 161.7 ± 6.4 cm, 61.6 ± 9.2 kg) undertook respiratory-function and walking-performance tests. Active men and women achieved higher scores than their inactive counterparts for all tests except spirometry, where no differences were evident. The results indicate that a significant amount of the elevated fitness level might be accounted for by increased endurance capacity of the inspiratory muscles. Inactive older individuals might be at risk for inadequate respiratory-muscle strength, so interventions should be considered
Analysis of the N-terminal region of human MLKL, as well as two distinct MLKL isoforms, reveals new insights into necroptotic cell death
© 2016 Authors. The pseudokinase mixed lineage kinase domain-like (MLKL) is an essential effector of necroptotic cell death. Two distinct human MLKL isoforms have previously been reported, but their capacities to trigger cell death have not been compared directly. Herein, we examine these two MLKL isoforms, and further probe the features of the human MLKL N-terminal domain that are required for cell death. Expression in HEK293T cells of the N-terminal 201 amino acids (aa) of human MLKL is sufficient to cause cell death, whereas expression of the first 154 aa is not. Given that aa 1125 are able to initiate necroptosis, our findings indicate that the helix that follows this region restrains necroptotic activity, which is again restored in longer constructs. Furthermore, MLKL isoform 2 (MLKL2), which lacks much of the regulatory pseudokinase domain, is a much more potent inducer of cell death than MLKL isoform 1 (MLKL1) in ectopic expression studies in HEK293T cells. Modelling predicts that a C-terminal helix constrains the activity of MLKL1, but not MLKL2. Although both isoforms are expressed by human monocyte-derived macrophages at the mRNA level, MLKL2 is expressed at much lower levels. We propose that it may have a regulatory role in controlling macrophage survival, either in the steady state or in response to specific stimuli
Lack of effect of citalopram on magnetic resonance spectroscopy measures of glutamate and glutamine in frontal cortex of healthy volunteers
Magnetic resonance spectroscopy (MRS) is a non-invasive imaging technique that
can provide localised measures of brain chemistry in vivo. We
previously found that healthy volunteers receiving the selective serotonin
reuptake inhibitor, citalopram, daily for 1 week showed higher levels of a
combined measure of glutamate and glutamine (Glx) in occipital cortex than those
receiving placebo. The aim of this study was to assess if a similar effect could
be detected in the frontal brain region. Twenty-three healthy volunteers
randomised to receive either citalopram 20 mg or a placebo capsule daily for
7–10 days were studied and scanned using a 3T Varian INOVA system
before and at the end of treatment. Standard short-TE (echo time) PRESS
(Point-resolved spectroscopy) (TE = 26 ms) and PRESS-J spectra were acquired
from a single 8-cm3 voxel in a frontal region incorporating anterior
cingulate cortex. Glutamate and total Glx levels were quantified both relative
to creatine and as absolute levels. Relative to placebo, citalopram produced no
change in Glx or glutamate alone at the end of the study. Similarly, no effect
was seen on other MRS measures studied: myo-inositol, choline,
N-acetylaspartate and creatine. These data suggest that the
effects of serotonin reuptake to modify cortical glutamatergic MRS measures may
be regionally specific. This supports the potential for MRS in assessing
neuroanatomically specific serotonin-glutamate interactions in the human
brain
Single-beam three-dimensional optical trapping at extremely low insertion angles via optical fiber optimization
Employing optical fiber to deliver the trapping laser to the sample chamber significantly reduces the size and costs of optical tweezers (OT). The utilization of fiber decouples the OT from the microscope, providing scope for system portability, and the potential for uncomplicated integration with other advanced microscopy systems. For use with an atomic force microscope, the fiber must be inserted at an angle of 10 deg to the plane of the sample chamber floor. However, the literature states that optical trapping with a single fiber inserted at an angle ≤20 deg is not possible. This paper investigates this limitation and proposes a hypothesis that explains it. Based on this explanation, a tapered-fiber optical tweezer system is developed. This system demonstrates that such traps can indeed be made to function in three-dimensions (3-D) at insertion angles of ≤10 deg using relatively low optical powers, provided the fiber taper is optimized. Three such optimized tapered fiber tips are presented, and their ability to optically trap both organic and inanimate material in 3-D is demonstrated. The near-horizontal insertion angle introduced a maximum trapping range (MTR). The MTR of the three tips is determined empirically, evaluated against simulated data, and found to be tunable through taper optimization
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Comparison of breath-hold, respiratory navigated and free-breathing MR elastography of the liver
Hepatic magnetic resonance elastography (MRE) is currently a breath-hold imaging technique. Patients with chronic liver disease can have comorbidities that limit their ability to breath-hold (BH) for the required acquisition time. Our aim was to evaluate whether stiffness measurements obtained from a navigator-triggered MRE acquisition are comparable to standard expiratory breath-hold, inspiratory breath-hold or free-breathing in healthy participants.
Twelve healthy participants were imaged using the four methods on a clinical 1.5 T MR system equipped with a product MRE system. Mean liver stiffness, and measurable area of stiffness (with a confidence threshold >95%) were compared between sequences using the concordance correlation coefficient. Repeatability of each sequence between two acquisitions was also assessed.
The standard BH expiratory technique had high concordance with the navigated technique (r = 0.716), and low concordance with the BH inspiration (r = 0.165) and free-breathing (r = 0.105) techniques. The navigator-triggered technique showed no statistical difference in measurable area of liver or in repeatability compared with the standard expiratory acquisition (p = 0.997 and p = 0.407 respectively). The free-breathing technique produced less measurable liver area and was less repeatable than the alternative techniques. The increase in acquisition time for navigator techniques was 3 min 6 s compared to standard expiratory breath-hold.
Navigator-based hepatic MRE measurements are comparable to the reference standard expiratory breath-hold acquisition in healthy participants.This work was supported by the Addenbrooke's Charitable Trust and the NIHR Comprehensive Biomedical Research Centre award to Cambridge University Hospitals NHS Foundation Trust in partnership with the University of Cambridge
Purchasing popular purebreds: investigating the influence of breed-type on the pre-purchase motivations and behaviour of dog owners
How and why dog owners select a specific breed may impact upon the health of the dog they acquire, and upon the wider health of the breed they select. Brachycephalic breeds are rapidly increasing in popularity despite increasing evidence linking brachycephalism with chronic and severe health conditions. This study used a questionnaire to explore pre-, during and post-purchase behaviours and attitudes of dog-owners who own popular brachycephalic dog breeds (n = breeds) compared to popular non-brachycephalic dog breeds (n = breeds). The survey received 1,427 valid responses. Brachycephalic breed owners were younger, more likely to live with children, and to be buying their chosen breed for the first time. The factor that most highly influenced brachycephalic owners decisions to buy their breed was appearance, followed by breed size suited to lifestyle, good dog breed for children and good companion breed. Perceived health of the breed was less influential in decision-making for brachycephalic owners compared to non-brachycephalic owners. The way in which owners acquired their dog differed by breed type, with brachycephalic owners more likely to use puppy-selling websites to find their dog, less likely to see either parent of their puppy, and less likely to ask to see any health records. Despite many brachycephalic breed health issues being directly related to conformation, appearance remains the most significant determinant in why people desire these breeds. More targeted educational interventions are needed to change buyer attitudes and, if ineffective, other more direct mechanisms (eg legislation) may be required to protect canine welfare
A Systematic Review of Music Therapy Practice and Outcomes with Acute Adult Psychiatric In-Patients
PMCID: PMC3732280This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
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