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Childhood maltreatment (CM) plays an important role in the development of major depressive disorder (MDD). The aim of this study was to examine whether CM severity and type are associated with MDD-related brain alterations, and how they interact with sex and age.
Within the ENIGMA-MDD network, severity and subtypes of CM using the Childhood Trauma Questionnaire were assessed and structural magnetic resonance imaging data from patients with MDD and healthy controls were analyzed in a mega-analysis comprising a total of 3872 participants aged between 13 and 89 years. Cortical thickness and surface area were extracted at each site using FreeSurfer.
CM severity was associated with reduced cortical thickness in the banks of the superior temporal sulcus and supramarginal gyrus as well as with reduced surface area of the middle temporal lobe. Participants reporting both childhood neglect and abuse had a lower cortical thickness in the inferior parietal lobe, middle temporal lobe, and precuneus compared to participants not exposed to CM. In males only, regardless of diagnosis, CM severity was associated with higher cortical thickness of the rostral anterior cingulate cortex. Finally, a significant interaction between CM and age in predicting thickness was seen across several prefrontal, temporal, and temporo-parietal regions.
Severity and type of CM may impact cortical thickness and surface area. Importantly, CM may influence age-dependent brain maturation, particularly in regions related to the default mode network, perception, and theory of mind.
SN 1987A has been observed with a combined high energy γ-ray (50-500 MeV) and hard X-ray (15-150 keV) payload during a balloon flight on 5 April 1988 from Alice Springs, Australia. The γ-ray observations, along with our earlier ones on 19 April 1987 are the only such observations of the supernova to date. The γ-ray detector characteristics are described. The preliminary results of the recent flight and their implications in terms of the known supernova parameters are discussed.
Harvesting solar energy, is only one of the incentives of incorporating photosynthetic proteins in electrochemical devices. Understanding the interface of photosynthetic protein complexes and organic\inorganic underlying electrodes can give rise to development of new generation of nano-bioelectronics for other applications such as sensing, as well. Previous approaches in fabricating photosynthetic bio-hybrid electrochemical solar cells were mainly based on metallic electrodes with protein complexes attached, either directly or through linker molecules. Due to the energy band structure in semiconductors, they potentially can be useful for selective charge transfer in an electrochemical device. In the current study, a two terminal sealed bio-hybrid solar cell device was fabricated comprising of hydrothermally grown ZnO nanowires on fluorine doped tin oxide (FTO) glass working electrode, a Pt counter electrode, and methyl viologen (MV) as a single diffusible redox mediator. The ZnO working electrode was initially characterized using scanning electron microscopy (XRD) and X-ray diffraction (XRD). A solution of dimeric Rhodobacter sphaeroides – light harvesting 1 (RC-LH1) core complexes and redox electrolyte was injected into the cavity between working and counter electrodes. Such structure resulted in ∼0.64 µA.cm-2 photocurrent density and ∼0.24 V open circuit potential difference in the dark and under illumination. Additionally, the device stability tests demonstrated that the current response of such devices remained unchanged after 33 hours storage in the dark.
The average rate of decline of butterfly species in the British Isles has been high in recent decades, exceeding that of breeding birds or native vascular plants. Nearly a third of species, however, has increased, and several have expanded their ranges northwards. Some clear patterns are evident from these changes. Most losses are attributable to a decline of the specialised habitats required by the caterpillar stages in species' life cycles, either through fundamental ecosystem destruction, for example through intensive farming, or more subtle degradation, when surviving ecosystems have become shadier or more overgrown. The fragmentation of extensive breeding sites into small isolated patches has also been a major obstacle for some species. Climate warming, to date, has benefited all but the few northern species of butterfly, but is likely to become a major driver of decline in future decades. It was only after conservationists began to understand the causes of change in British butterflies that they were able to restore populations, through targeted land management, to former ecosystems. This process began successfully in the 1970s, and is probably responsible for the survival today of the Heath Fritillary, Silver-spotted Skipper and Adonis Blue.
Just 71 species of butterfly have regularly been recorded in the British Isles since the first list of native insects was published in 1634, by Thomas Moffett in Insectorum Theatrum.
The influence of incorporating nanoparticulate additions into Ca3Co4O9 (CCO) thin films prepared by pulsed laser deposition using composite targets of CCO and CCO + 3wt% BaZrO3 (BZO) on Si and LaAlO3 substrates is investigated. X-ray data and high-resolution scanning electron microscopy reveal preferred c-axis orientation of the films deposited on Si substrates with the formation of nanoparticles between ∼ 10 – 50 nm. Preliminary thermoelectric behavior shows an enhancement of the power factor α2/ρ at room temperature. The microstructure and thermoelectric behavior of the CCO films are compared to the BZO-doped films.
Lead cut-outs used to shape fields in kilovoltage radiotherapy can increase the surface dose on the patient. The physical processes leading to increased surface doses are summarised, and an empirical investigation of the efficacy of various coatings in reducing the skin dose generated by secondary electrons released in the lead during irradiation is presented, based on measurements using a thin window parallel plate ionisation chamber in 135 kVp and 225 kVp beams from a Pantak DXT-300 kilovoltage therapy unit. A new flexible coating for lead cut-outs has been formulated and tested. This coating, which is a combination of Copydex and emulsion paint, has been shown to be effective in reducing the skin dose generated by secondary electrons released in the lead during irradiation. The coating is easy to clean, and its inherent elasticity prevents cracking of the coating in clinical use. Its only disadvantage is that rough handling, or contact with sharp objects, can peel the coating at the point of contact.
The merits of atom-probe tomography (APT) of inorganic materials are well established, as described in this volume. However, one of the long-held aspirations of atom-probe scientists, structural and chemical characterization of organic and biological materials at near-atomic resolution, has yet to be fully realized. A few proof-of-concept type investigations have shown that APT of organic materials is feasible, but a number of challenges still exist with regard to specimen preparation and conversion of raw time-of-flight mass spectrometry data into a three-dimensional map of ions containing structural and chemical information at an acceptable resolution. Recent research aided by hardware improvements and specimen preparation advances has made some progress toward this goal. This article reviews the historical developments in this field, presents some recent results, and considers what life science researchers might expect from this technology.
Visible-light-driven Ag3VO4 photocatalysts were successfully synthesized using low-temperature hydrothermal synthesis method. Under various hydrothermal conditions, the structures of silver vanadates were tuned by manipulating the hydrothermal time and the ratio of silver to vanadium. X-ray diffraction (XRD) results reveal that the powders prepared in a stoichiometric ratio consisted of pure α-Ag3VO4 or mixed phases of Ag4V2O7 and α-Ag3VO4. With increasing the Ag-to-V mole ratio to 6:1, the resulting samples were identified as pure monoclinic structure α-Ag3VO4. UV-vis spectroscopy indicated that silver vanadate particles had strong visible light absorption with associated band gaps in the range of 2.2-2.5 eV. The sample synthesized in the excess silver exhibited higher photocatalytic activity than that synthesized in a stoichiometric ratio. The powder synthesized at silver-rich at 140℃ for 4 h (SHT4) exhibited the highest photocatalytic activity among all samples. The reactivity of SHT4 (surface area, 3.52 m2 g-1) on the decomposition of gaseous benzene was about 16 times higher than that of P25 (surface area, 49.04 m2 g-1) under visible light irradiation. A well developed crystallinity of Ag3VO4 of SHT 4 was considered to enhance the photocatalytic efficiency.
TiO2, TiO2-1at.% W and TiO2-1at.% Cr were produced from metal-organic precursors by flame spray synthesis (FSS). TiO2-0.5at.% N was obtained by ammonolysis of FSS made TiO2 nanopowder in a rotating tube furnace under NH3 atmosphere. According to the X-ray diffraction (XRD) analysis, anatase is the predominant phase in all samples. Diffusive reflectance and the resulting band gap energy (Eg) were determined by diffusive reflection spectroscopy (DRS).
Additional impurity bands at 2.43 and 2.57 eV for N- and Cr-doped TiO2, respectively have been observed. The impurity band formed in the band gap resulted in increase of the light absorption in the visible range. The photocatalytic performance of the nanopowders under ultraviolet (UV, 290-410 nm) and visible light irradiation (Vis, 400-500 nm) was studied by the degradation of methylene blue (MB) in aqueous suspensions. It was found that all types of dopants influence the structure, interaction with the visible light as well as photocatalytic activity. Among all nanopowders, TiO2-W exhibited the best photoactivity, much higher than the commercial TiO2-P25 nanopowder. The optimum of the photodecolourization was obtained for 0.7 and 1 at.% W.
Exploring the cell-material interface is an emerging area of great interest in biomaterial science. Specifically, creating nanostructured surface interfaces to improve biomaterial efficacy is one of these key focus topics. As an example, an increasing number of studies have demonstrated the positive role nanostructured surfaces can have towards promoting various cell functions. However, the relevant mechanism behind this improvement in biological interactions at the cell-implant interface is not well understood. For this reason, here, osteoblast (bone forming cells) and fibroblast (fibrous, soft tissue forming cells) functions (including adhesion and proliferation) on two carefully fabricated diamond films with dramatically different topographies were tested. The results revealed greater cell responses on nanocrystalline diamond (grain sizes <100nm) compared to submicron crystalline diamond (grain sizes 200˜1000nm). In order to understand this positive impact of diamond nanotopography on cell responses, fibronectin absorption and subsequent cell spreading were studied. More importantly, cell filopodia extensions were also studied through computational mechanical modeling. A deflection-diffusion model of cell filopodia extension was established and clearly suggested that increasing the lateral dimension or height of nanometer surface features could inhibit cell filopodia extension and decrease cell spreading. Both the experiments and modeling from this study indicated that a nanometer surface topography can enhance cell responses to promote implant efficacy.
Osteoarthritis (OA) and Osteochondritis Dissecans (OCD) are osteoarticular disorders that cause leg weakness, lameness, pain and suffering in companion animals, some farm animals and humans. OA is one of the most common age-related osteoarticular disorders in humans and dogs. In pigs, both OA and OCD are thought to arise from changes in the articular cartilage and growth plates within the synovial joints causing structural damage to joint tissues. Since these changes are not observed in the slow maturing wild boar, they are suggested to be a result of the modern intensive pig production industry which has very successfully selected pigs for rapid growth rates, large muscle mass and efficient feed conversion placing increased weight and mechanical stress on growth plates. The aim of this study was to establish canine and porcine articular cartilage explant models which are essentially tissue culture techniques for isolating and maintaining cartilage tissue ex vivo for subsequent assessment of potentially beneficial effects of specific phytonutrients. Bacterial lipopolysaccharide (LPS) was used as a catabolic mediator to create a culture model of joint inflammation mimicking the events that occur in late stages of OA and OCD. We then performed assays to determine if the dietary phytochemical ‘curcumin’ (derived from Curcuma longa) and the polyphenolic phytoalexin stilbene ‘resveratrol’ (found in red grapes, red wine, peanuts and some berries) are able to counteract the catabolic effects of LPS by inhibiting LPS stimulated release of cartilage matrix glycosaminoglycans (GAGs).
LOFAR (Low Frequency Array) is an innovative radio telescope optimized for the frequency range 30–240 MHz. The telescope is realized as a phased aperture array without any moving parts. Digital beam forming allows the telescope to point to any part of the sky within a second. Transient buffering makes retrospective imaging of explosive short-term events possible. The scientific focus of LOFAR will initially be on four key science projects (KSPs): (i) Detection of the formation of the very first stars and galaxies in the universe during the so-called epoch of reionization by measuring the power spectrum of the neutral hydrogen 21-cm line (Shaver et al. 1999) on the ∼ 5′ scale; (ii) Low-frequency surveys of the sky with of order 108 expected new sources; (iii) All-sky monitoring and detection of transient radio sources such as γ-ray bursts, X-ray binaries, and exo-planets (Farrell et al. 2004); and (iv) Radio detection of ultra-high energy cosmic rays and neutrinos (Falcke & Gorham 2003) allowing for the first time access to particles beyond 1021 eV (Scholten et al. 2006). Apart from the KSPs open access for smaller projects is also planned. Here we give a brief description of the telescope.
We report on an approach towards integrated complementary-like circuits based on organic ambipolar transistors. In particular, we show that ambipolar transport can be achieved within a single transistor channel using gold electrodes and a solution processable polymer-small molecule blend as the electroactive material. To demonstrate the suitability of these devices for practical utilisation in logic circuits we realise complementary-like voltage inverters comprised entirely of ambipolar transistors. Moreover, by integrating several such inverters we are able to demonstrate more complex circuits such as ring oscillators.
We describe a recently discovered magnetoresistance (MR) effect in semiconducting polymer and small molecule sandwich devices. The MR effect reaches up to 10% in a magnetic field of 10mT at room temperature. This MR effect is therefore amongst the largest of any bulk material. We characterize this effect and discuss its dependence on voltage, film thickness, temperature, electrode materials and (unintentional) impurity concentration in three different organic semiconductors. We found that the MR effect is only weakly temperature dependent and does not depend on sign and direction of the applied magnetic field. To the best of our knowledge, the discovered MR effect is not adequately described by any of the mechanisms known to date.
A new application of the electrochemical method, in situ chronoamperometry, has been developed and used as a tool for CMP slurry characterization. The measured current response, i, resulting from a small applied potential is fit to an exponential equation, i = io + A1exp(-t/tD). The fitting parameters serve as a measure of surface reactivity (io), surface film robustness (A1), and the kinetics of film formation (tD). A description of the method and correlations to polishing performance are discussed in this paper.
Nanoporous templates made from diblock copolymer films are used for electrochemical fabrication of hexagonal arrays of vertical cobalt magnetic nanowires at terabit/in2 density. The nanowire diameter and areal density are determined by the copolymer molecular weight, whereas the nanowire length and internal crystal morphology are controlled through the dc electrodeposition growth process. The array magnetic properties can be modified substantially by electrodeposition pH conditions while keeping wire size and interwire distance constant. Optimum pH control results in preferential growth of c-axis oriented crystallites with large perpendicular coercivity. The appearance of exchange bias behavior, exhibited at low temperatures, is also investigated.
Affordable, high quality SiC wafers are very desirable for a variety of new technologies including GaN based lighting, RF, and high-power electronics based on wide band gap materials. At Litton Airtron we have a major effort in the growth and characterization of SiC. We will present data on 35, 50 and 75-mm diameter crystals. We are growing both n-type, semiinsulating 4H, 6H, and 15R material. A variety of characterization techniques are being used at Litton Airtron to determine wafer quality. These include Raman microscopy, digital wafer photography, and crossed polarizer images. Raman spectroscopy is an excellent probe of polytype and carrier concentration for n-type materials; in addition it can be done at room temperature and is sufficiently fast that it can be used in an industrial environment. The use of digital photography allows for the collection of images that can be quantitatively analyzed and archived.
The status of SiC vapor growth technique (PVT) is reviewed and related innovative aspects are introduced. Problems of the preparation of SiC crystals with uniform electronic properties are addressed, especially the growth of semiinsulating SiC. An overview about the performance of numerical modeling is given as tool for the optimization of the PVT process. Development activities in the field of liquid phase processing for the preparation of SiC bulk crystals and micropipe healing are presented. Finally recent results on the present understanding of filamentary void formation/elimination (micropipes, macrodefects) are summarized.
Nanostructures are electrochemically deposited into alumina or polycarbonate templates resulting in monodisperse, anisotropic particles with a range of tunable sizes. These particles have been synthesized with diameters of 20–250 nm and with lengths of 1–10 μm. Currently, structures have been made with stripes of Au, Ag, CdSe, Co, Cu, Ni, Pd, and Pt. These materials offer a variety of different properties. In particular, many of the metals in this group are excellent conductors, meaning these particles can actually be used as nanowires. Co and Ni are ferromagnetic and may be used for separation or assembly. CdSe is a semiconductor, possibly allowing for the synthesis of electronic devices such as transistors. Furthermore, many of these materials have different surface chemistries, making the orthogonal functionalization and assembly of these nanowires more accessible. This research focuses on increasing the number of materials available, especially semiconductors, incorporating these potentially useful materials into multilayered nanowires and evaluating their electrical properties, either individually or in small bundles. In addition, the surface chemistry of the various materials in the nanowires is being compared to aid in orthogonal self-assembly of functional nanostructures such as memory devices. The work presented will demonstrate the effects of rod composition on electrical properties. In particular, the effects of changing the work function of the materials on either side of a semiconductor to form Schottky junctions or ohmic contacts will be shown.