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Structural variation in subcortical brain regions has been linked to substance use, including the most commonly used substances nicotine and alcohol. Pre-existing differences in subcortical brain volume may affect smoking and alcohol use, but there is also evidence that smoking and alcohol use can lead to structural changes.
We assess the causal nature of the complex relationship of subcortical brain volume with smoking and alcohol use, using bi-directional Mendelian randomisation.
Mendelian randomisation uses genetic variants predictive of a certain ‘exposure’ as instrumental variables to test causal effects on an ‘outcome’. Because of random assortment at meiosis, genetic variants should not be associated with confounders, allowing less biased causal inference. We used summary-level data of genome-wide association studies of subcortical brain volumes (nucleus accumbens, amygdala, caudate, hippocampus, pallidum, putamen and thalamus; n = 50 290) and smoking and alcohol use (smoking initiation, n = 848 460; cigarettes per day, n = 216 590; smoking cessation, n = 378 249; alcoholic drinks per week, n = 630 154; alcohol dependence, n = 46 568). The main analysis, inverse-variance weighted regression, was verified by a wide range of sensitivity methods.
There was strong evidence that liability to alcohol dependence decreased amygdala and hippocampal volume, and smoking more cigarettes per day decreased hippocampal volume. From subcortical brain volumes to substance use, there was no or weak evidence for causal effects.
Our findings suggest that heavy alcohol use and smoking can causally reduce subcortical brain volume. This adds to accumulating evidence that alcohol and smoking affect the brain, and likely mental health, warranting more recognition in public health efforts.
The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.
In the current work, we evaluate the influence of the processing parameters on the electrical properties of aluminium zinc oxide (AZO) thin films produced by airbrush spray-pyrolysis deposition technique. Spray-deposited AZO thin-films were produced with Al:Zn molar ratios varying from 0 % (pure ZnO) up to 30 %, using aluminium acetate and zinc acetate as organic precursors and water as solvent. Thermogravimetric analysis (TGA) and infrared spectroscopy (FTIR-ATR) were used to monitor the metal-oxide formation from the organic precursors as a function of the temperature. The results show that a temperature of 400 °C is necessary to completely degrade the organic phase and to obtain the desired inorganic metal-oxides films. The electrical properties of the TMOs were evaluated by d.c. current-voltage (I-V) analysis using planar thermally evaporated Al electrodes on top of the TMO layer, with different aspect ratios (1/18, 2/9, 5/13, 5/9 and 8/9). The lowest sheet resistance was obtained for AZO films at a molar Al concentration of 5 %. We also observed that, after carrying out a post-annealing treatment (30 mbar, 150 °C) the samples presented a decrease on the sheet resistance superior to 60 %, in comparison to the samples before the treatment.
This paper presents small balanced bandpass filters exhibiting wide differential-mode pass bands and high common-mode suppression. The filters are implemented in microstrip technology and their topology consists of multisection mirrored stepped impedance resonators (SIRs) alternating with mirrored interdigital capacitors. The mirrored SIRs provide the required common-mode transmission zeros to achieve effective rejection of that mode in the region of interest, i.e. the differential-mode pass band. An automated design method for such filters, based on aggressive space mapping, is reported. The method uses the equivalent circuit model of both the mirrored SIRs and the interdigital capacitors, and filter synthesis is based on a quasi-Newton iterative algorithm where parameter extraction is the key aspect. The automated design approach is illustrated through an order-3 filter, where it is demonstrated that the filter topology is generated from the specifications. As compared with previous balanced filters based on mirrored SIRs coupled through admittance inverters, the proposed filters of this work are smaller and the design method is simplified, since bandwidth compensation due to the narrowband functionality of the inverters is avoided.
The surface properties of hydroxyapatite, including electric charge, can influence the biological response, tissue compatibility, and adhesion of biological cells and biomolecules. Results reported here help in understanding this influence by creating charged domains on hydroxyapatite thin films deposited on silicon using electron beam irradiation and investigating their shape, properties, and carbon contamination for different doses of incident injected charge by two methods. Photoluminescence laser scanning microscopy was used to image electrostatic charge trapped at pre-existing and irradiation-induced defects within these domains, while phase imaging in atomic force microscopy was used to image the carbon contamination. Scanning Auger electron spectroscopy and Kelvin probe force microscopy were used as a reference for the atomic force microscopy phase contrast and photoluminescence laser scanning microscopy measurements. Our experiment shows that by combining the two imaging techniques the effects of trapped charge and carbon contamination can be separated. Such separation yields new possibilities for advancing the current understanding of how surface charge influences mediation of cellular and protein interactions in biomaterials.
To examine the use of vitamin D supplements during infancy among the participants in an international infant feeding trial.
Information about vitamin D supplementation was collected through a validated FFQ at the age of 2 weeks and monthly between the ages of 1 month and 6 months.
Infants (n 2159) with a biological family member affected by type 1 diabetes and with increased human leucocyte antigen-conferred susceptibility to type 1 diabetes from twelve European countries, the USA, Canada and Australia.
Daily use of vitamin D supplements was common during the first 6 months of life in Northern and Central Europe (>80 % of the infants), with somewhat lower rates observed in Southern Europe (>60 %). In Canada, vitamin D supplementation was more common among exclusively breast-fed than other infants (e.g. 71 % v. 44 % at 6 months of age). Less than 2 % of infants in the USA and Australia received any vitamin D supplementation. Higher gestational age, older maternal age and longer maternal education were study-wide associated with greater use of vitamin D supplements.
Most of the infants received vitamin D supplements during the first 6 months of life in the European countries, whereas in Canada only half and in the USA and Australia very few were given supplementation.
Developments of composites materials had begun in the 1970's. They aimed in improving mechanical properties due to the presence of reinforcement particles. The addition of particles in a matrix led to different modifications: considering the nature of the phases and the microstructure, we can mention interface reactivity between matrix and particles, changes in the chemical composition of the matrix and modified kinetics of microstructure evolution in the matrix (as compared to the matrix without particles); considering the mechanical aspects, thermal stresses may be generated due to the differences in expansion coefficients between the particles and the matrix, or any changes in the matrix leading to a phase transformation. In the present work, we studied the evolution of the phases and the behavior of a steel based MMC during thermal treatments, for which a phase transformation occurred on cooling. Experiments and numerical simulation are considered.
Nançay radio astronomy station teams are involved in several aspects of the Research and Development (R&D)
for radio astronomy detectors and systems:
i) Microelectronics: Low Noise Amplifiers (LNA), receiver on chip and
system in package. The long-term goal is to provide sub-systems for
the future Square Kilometer Array and its Pathfinders. A beamformer chip has been integrated
in the FP6 SKADS dense aperture array technology demonstrator EMBRACE. Wide band SiGe LNAs are
developed, beamformers with in-chip control are studied and more
complex integrated receivers are designed for the european Aperture Array
Verification Programme demonstrator.
ii) Digital signal processing: EMBRACE beamforming has been implemented
in the digital backend and RFI-mitigation oriented
signal processing has been designed for realtime systems,
including work for FP6 SKADS and FP7 PrepSKA.
iii) A study of Phased Array Feeds has started in 2008, in order to study
the radio electric properties of PAFs at the focus of large F/D
telescopes, such as the Nançay Radio Telescope, as well as to test PAF
systems in collaboration with the SPP/IRFU and LAL/IN2P3 laboratories.
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