Highly active TiO2-based photocatalaysts for indoor air remediation

Energy saving policies applied to modem buildings and air recirculation systems promote the build up of high levels of VOCs in indoor air. The growing concern related to the air quality in indoor environments requires the replacement of ineffective traditional purification methods, with an efficient and cost effective technology. Photocatalytic oxidation that utilise TiO2, represents a promising candidate for this purpose. However, the formulation of photocatalysts that can efficiently utilise a sustainable energy source (i.e. solar light), still represents an ambitious target in this field. In this study, different TiO2-based photocatalysts were synthesised by modified sol-gel and/or hydrothermal routes. The materials were characterised by XRD, SEM, N2 sorption (BET and BJH methods), UV-vis Spectroscopy and XPS. The photocatalytic activity of TiO2-based materials was systematically investigated at different light intensities, in a gas-phase flatplate photoreactor, using trichloroethylene (TCE) as model pollutant, and compared with that of the commercial product TiO2 Degussa P-25. This research provides insights into the influence of preparation parameters on different synthetical pathways for the preparation of highly active TiO2- based photocatalysts. The general approach to this investigation is based on the study of the influence of several processing parameters on morphological, textural and crystallographic properties of the photocatalysts, in order to correlate the material's features with their photocatalytic properties. The preparation of a wide range of pristine TiO2 allowed assessing a clear correlation between phase composition and crystal size and the photocatalytic performance. A series of highly active anatase photocatalysts was prepared. The best photocatalyst has an optimum crystal size of 28 nm and exhibits a photocatalytic activity that exceeds that of P-25 by a factor of over 2 times. A new TiO2/WO3 nanocomposites with peculiar crystallographic properties of the W component was developed by a novel one-step hydrothermal synthesis. The synthesis conditions were optimised with respect to the photocatalytic activity. Overall, the optimisation of the properties that enable an efficient interfacial charge transfer rate at the catalyst surface was found to be of fundamental importance for the design of improved TiO2-based photocatalysts

Highly active TiO2-based photocatalaysts for indoor air remediation

Energy saving policies applied to modem buildings and air recirculation systems promote the build up of high levels of VOCs in indoor air. The growing concern related to the air quality in indoor environments requires the replacement of ineffective traditional purification methods, with an efficient and cost effective technology. Photocatalytic oxidation that utilise TiO2, represents a promising candidate for this purpose. However, the formulation of photocatalysts that can efficiently utilise a sustainable energy source (i.e. solar light), still represents an ambitious target in this field. In this study, different TiO2-based photocatalysts were synthesised by modified sol-gel and/or hydrothermal routes. The materials were characterised by XRD, SEM, N2 sorption (BET and BJH methods), UV-vis Spectroscopy and XPS. The photocatalytic activity of TiO2-based materials was systematically investigated at different light intensities, in a gas-phase flatplate photoreactor, using trichloroethylene (TCE) as model pollutant, and compared with that of the commercial product TiO2 Degussa P-25. This research provides insights into the influence of preparation parameters on different synthetical pathways for the preparation of highly active TiO2- based photocatalysts. The general approach to this investigation is based on the study of the influence of several processing parameters on morphological, textural and crystallographic properties of the photocatalysts, in order to correlate the material's features with their photocatalytic properties. The preparation of a wide range of pristine TiO2 allowed assessing a clear correlation between phase composition and crystal size and the photocatalytic performance. A series of highly active anatase photocatalysts was prepared. The best photocatalyst has an optimum crystal size of 28 nm and exhibits a photocatalytic activity that exceeds that of P-25 by a factor of over 2 times. A new TiO2/WO3 nanocomposites with peculiar crystallographic properties of the W component was developed by a novel one-step hydrothermal synthesis. The synthesis conditions were optimised with respect to the photocatalytic activity. Overall, the optimisation of the properties that enable an efficient interfacial charge transfer rate at the catalyst surface was found to be of fundamental importance for the design of improved TiO2-based photocatalysts

Preparation of hexagonal GeO2 particles with particle size and crystallinity controlled by peptides, silk and silk-peptide chimeras

We demonstrate the use of silk based proteins to control the particle/crystallite size during GeO2 formation, using a bio-mimetic approach at circumneutral pH and ambient temperature. Multicrystalline GeO2 was prepared from germanium tetraethoxide (TEOG) in the presence of different silk-based proteins: Bombyx mori silk (native silk) and two chimeric proteins prepared by linking a germania binding peptide (Ge28: HATGTHGLSLSH) with Bombyx mori silk via chemical coupling at different peptide loadings (silk-Ge28 10% and silk-Ge28 50%). The mineralisation activity of the silk-based proteins was compared with that of peptide Ge28 as a control system. GeO2 mineralisation was investigated in water and in citric acid/bis-tris propane buffer at pH 6. Morphology, particle size, crystallinity, water and organic content of the materials obtained were analysed to study the effect of added biomolecules and mineralisation environment on material properties. In the presence of silk additives well-defined cube-shape hybrid materials composed of hexagonal germania and up to ca. 5 wt% organic content were obtained. The cubic particles ranged from 0.4 to 1.4m in size and were composed of crystalline domains in the range 35-106 nm depending on the additive used and synthesis conditions

Aqueous peptide-TiO2 interfaces: iso-energetic binding via either entropically- or enthalpically-driven mechanisms

A major barrier to the systematic improvement of biomimetic peptide-mediated strategies for the controlled growth of inorganic nanomaterials in environmentally benign conditions lies in the lack of clear conceptual connections between the sequence of the peptide and its surface binding affinity, with binding being facilitated by non-covalent interactions. Peptide conformation, both in the adsorbed and non-adsorbed state, is the key relationship that connects peptide-materials binding with peptide sequence. Here, we combine experimental peptide–titania binding characterization with state-of-the-art conformational sampling via molecular simulations to elucidate these structure/binding relationships for two very different titania-binding peptide sequences. The two sequences (Ti-1: QPYLFATDSLIK and Ti-2: GHTHYHAVRTQT) differ in their overall hydropathy, yet via quartz-crystal microbalance measurements and predictions from molecular simulations, we show these sequences both support very similar, strong titania-binding affinities. Our molecular simulations reveal that the two sequences exhibit profoundly different modes of surface binding, with Ti-1 acting as an entropically-driven binder while Ti-2 behaves as an enthalpically-driven binder. The integrated approach presented here provides a rational basis for peptide sequence engineering to achieve the in-situ growth and organization of titania nanostructures in aqueous media and for the design of sequences suitable for a range of technological applications that involve the interface between titania and biomolecules

Clinical global impression-severity score as a reliable measure for routine evaluation of remission in schizophrenia and schizoaffective disorders

Aims: This study aimed to compare the performance of Positive and Negative Syndrome Scale (PANSS) symptom severity criteria established by the Remission in Schizophrenia Working Group (RSWG) with criteria based on Clinical Global Impression (CGI) severity score. The 6-month duration criterion was not taken into consideration. Methods: A convenience sample of 112 chronic psychotic outpatients was examined. Symptomatic remission was evaluated according to RSWG severity criterion and to a severity criterion indicated by the overall score obtained at CGI-Schizophrenia (CGI-SCH) rating scale (≤3) (CGI-S). Results: Clinical remission rates of 50% and 49.1%, respectively, were given by RSWG and CGI-S, with a significant level of agreement between the two criteria in identifying remitted and non-remitted cases. Mean scores at CGI-SCH and PANSS scales were significantly higher among remitters, independent of the remission criteria adopted. Measures of cognitive functioning were largely independent of clinical remission evaluated according to both RSWG and CGI-S. When applying RSWG and CGI-S criteria, the rates of overall good functioning yielded by Personal and Social Performance scale (PSP) were 32.1% and 32.7%, respectively, while the mean scores at PSP scale differed significantly between remitted and non-remitted patients, independent of criteria adopted. The proportion of patients judged to be in a state of well-being on Social Well-Being Under Neuroleptics-Short Version scale (SWN-K) were, respectively, 66.1% and 74.5% among remitters according to RSWG and CGI-S; the mean scores at the SWN scale were significantly higher only among remitters according to CGI-S criteria. Conclusions: CGI severity criteria may represent a valid and user-friendly alternative for use in identifying patients in remission, particularly in routine clinical practic

The third data release of the Kilo-Degree Survey and associated data products

The Kilo-Degree Survey (KiDS) is an ongoing optical wide-field imaging survey with the OmegaCAM camera at the VLT Survey Telescope. It aims to image 1500 square degrees in four filters (ugri). The core science driver is mapping the large-scale matter distribution in the Universe, using weak lensing shear and photometric redshift measurements. Further science cases include galaxy evolution, Milky Way structure, detection of high-redshift clusters, and finding rare sources such as strong lenses and quasars. Here we present the third public data release (DR3) and several associated data products, adding further area, homogenized photometric calibration, photometric redshifts and weak lensing shear measurements to the first two releases. A dedicated pipeline embedded in the Astro-WISE information system is used for the production of the main release. Modifications with respect to earlier releases are described in detail. Photometric redshifts have been derived using both Bayesian template fitting, and machine-learning techniques. For the weak lensing measurements, optimized procedures based on the THELI data reduction and lensfit shear measurement packages are used. In DR3 stacked ugri images, weight maps, masks, and source lists for 292 new survey tiles (~300 sq.deg) are made available. The multi-band catalogue, including homogenized photometry and photometric redshifts, covers the combined DR1, DR2 and DR3 footprint of 440 survey tiles (447 sq.deg). Limiting magnitudes are typically 24.3, 25.1, 24.9, 23.8 (5 sigma in a 2 arcsec aperture) in ugri, respectively, and the typical r-band PSF size is less than 0.7 arcsec. The photometric homogenization scheme ensures accurate colors and an absolute calibration stable to ~2% for gri and ~3% in u. Separately released are a weak lensing shear catalogue and photometric redshifts based on two different machine-learning techniques.Comment: small modifications; 27 pages, 12 figures, accepted for publication in Astronomy & Astrophysic

Interactions between metal oxides and biomolecules: from fundamental understanding to applications

Metallo-oxide (MO) based bioinorganic nanocomposites promise unique structures, physico-chemical properties and novel bio-chemical functionalities and within the last decade, investment in research on materials such as ZnO, TiO2, SiO2 and GeO2 has significantly increased. Besides traditional approaches, the synthesis, shaping, structural patterning and post-processing chemical functionalization of the materials surface is inspired by strategies which mimic processes in nature. Would such materials deliver new technologies? Answering this question requires the merging of historical knowledge and current research from different fields of science. Practically, we need an effective defragmentation of the research area. From our perspective, the superficial accounting of material properties, chemistry of the surfaces and the behaviour of biomolecules next to such surfaces is a problem. This is particularly of concern when we wish to bridge between technologies in vitro and biotechnologies in vivo. Further, besides the potential practical technological efficiency and advantages such materials might exhibit, we have to consider the wider long-term implications of material stability and toxicity. In this contribution we present a critical review of recent advances in the chemistry and engineering of MO based biocomposites highlighting the role of interactions at the interface and the techniques by which these can be studied. At the end of the article we outline the challenges which hamper progress in research and extrapolate to developing and promising directions including additive manufacturing and synthetic biology that could benefit from molecular level understanding of interactions occurring between inanimate (abiotic) and living (biotic) materials

Genome-wide Analyses Identify KIF5A as a Novel ALS Gene

To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.Peer reviewe

Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe