Controlled Porosity in Ferroelectric BaTiO₃ Photoanodes

The use of ferroelectric polarization to promote electron-hole separation has emerged as a promising strategy to improve photocatalytic activity. Although ferroelectric thin films with planar geometry have been largely studied, nanostructured and porous ferroelectric thin films have not been commonly used in photo-electrocatalysis. The inclusion of porosity in ferroelectric thin films would enhance the surface area and reactivity, leading to a potential improvement of the photoelectrochemical (PEC) performance. Herein, the preparation of porous barium titanate (pBTO) thin films by a soft template-assisted sol-gel method is reported, and the control of porosity using different organic/inorganic ratios is verified by the combination of scanning electron microscopy and ellipsometry techniques. Using piezoresponse force microscopy, the switching of ferroelectric domains in pBTO thin films is observed, confirming that the ferroelectric polarization is still retained in the porous structures. In addition, the presence of porosity in pBTO thin films leads to a clear improvement of the PEC response. By electrochemical poling, we also demonstrated the tuning of the PEC performance of pBTO thin films via ferroelectric polarization. Our work offers a simple and low-cost approach to control the morphology optimization of ferroelectric thin films, which could open up the development of materials with great potential for PEC applications

Cell-based Approaches to Joint Surface Repair : A Research Perspective

The authors are grateful for support to their research from Arthritis Research UK (grants 19271, 19429, 19667, 20050). None of the authors received any funding related to the writing of this manuscript, and the funding bodies did not play any role in the writing of the manuscript or decision to submit the manuscript for publication.Peer reviewedPublisher PD

Immunomodulation by Mesenchymal Stem Cells : A Potential Therapeutic Strategy for Type 1 Diabetes

Mesenchymal stem cells (MSCs) are pluripotent stromal cells that have the potential to give rise to cells of diverse lineages. Interestingly, MSCs can be found in virtually all postnatal tissues. The main criteria currently used to characterize and identify these cells are the capacity for self-renewal and differentiation into tissues of mesodermal origin, combined with a lack in expression of certain hematopoietic molecules. Because of their developmental plasticity, the notion of MSC-based therapeutic intervention has become an emerging strategy for the replacement of injured tissues. MSCs have also been noted to possess the ability to impart profound immunomodulatory effects in vivo. Indeed, some of the initial observations regarding MSC protection from tissue injury once thought mediated by tissue regeneration may, in reality, result from immunomodulation. Whereas the exact mechanisms underlying the immunomodulatory functions of MSC remain largely unknown, these cells have been exploited in a variety of clinical trials aimed at reducing the burden of immune-mediated disease. This article focuses on recent advances that have broadened our understanding of the immunomodulatory properties of MSC and provides insight as to their potential for clinical use as a cell-based therapy for immune-mediated disorders and, in particular, type 1 diabetes

Multicomplementary operators via finite Fourier transform

A complete set of d+1 mutually unbiased bases exists in a Hilbert spaces of dimension d, whenever d is a power of a prime. We discuss a simple construction of d+1 disjoint classes (each one having d-1 commuting operators) such that the corresponding eigenstates form sets of unbiased bases. Such a construction works properly for prime dimension. We investigate an alternative construction in which the real numbers that label the classes are replaced by a finite field having d elements. One of these classes is diagonal, and can be mapped to cyclic operators by means of the finite Fourier transform, which allows one to understand complementarity in a similar way as for the position-momentum pair in standard quantum mechanics. The relevant examples of two and three qubits and two qutrits are discussed in detail.Comment: 15 pages, no figure

Quantum information distributors: Quantum network for symmetric and asymmetric cloning in arbitrary dimension and continuous limit

We show that for any Hilbert-space dimension, the optimal universal quantum cloner can be constructed from essentially the same quantum circuit, i.e., we find a universal design for universal cloners. In the case of infinite dimensions (which includes continuous variable quantum systems) the universal cloner reduces to an essentially classical device. More generally, we construct a universal quantum circuit for distributing qudits in any dimension which acts covariantly under generalized displacements and momentum kicks. The behavior of this covariant distributor is controlled by its initial state. We show that suitable choices for this initial state yield both universal cloners and optimized cloners for limited alphabets of states whose states are related by generalized phase-space displacements.Comment: 10 revtex pages, no figure

An overview of the first 5 years of the ENIGMA obsessive–compulsive disorder working group: The power of worldwide collaboration

Abstract Neuroimaging has played an important part in advancing our understanding of the neurobiology of obsessive?compulsive disorder (OCD). At the same time, neuroimaging studies of OCD have had notable limitations, including reliance on relatively small samples. International collaborative efforts to increase statistical power by combining samples from across sites have been bolstered by the ENIGMA consortium; this provides specific technical expertise for conducting multi-site analyses, as well as access to a collaborative community of neuroimaging scientists. In this article, we outline the background to, development of, and initial findings from ENIGMA's OCD working group, which currently consists of 47 samples from 34 institutes in 15 countries on 5 continents, with a total sample of 2,323 OCD patients and 2,325 healthy controls. Initial work has focused on studies of cortical thickness and subcortical volumes, structural connectivity, and brain lateralization in children, adolescents and adults with OCD, also including the study on the commonalities and distinctions across different neurodevelopment disorders. Additional work is ongoing, employing machine learning techniques. Findings to date have contributed to the development of neurobiological models of OCD, have provided an important model of global scientific collaboration, and have had a number of clinical implications. Importantly, our work has shed new light on questions about whether structural and functional alterations found in OCD reflect neurodevelopmental changes, effects of the disease process, or medication impacts. We conclude with a summary of ongoing work by ENIGMA-OCD, and a consideration of future directions for neuroimaging research on OCD within and beyond ENIGMA

Paracrine signalling events in embryonic stem cell renewal mediated by affinity targeted nanoparticles

AbstractStem cell growth and differentiation is controlled by intrinsic and extrinsic factors. The latter includes growth factors, which are conventionally supplied in vitro in media exchanged daily. Here, we illustrate the use of affinity targeted biodegradable nanoparticles to mediate paracrine stimulation as an alternative approach to sustain the growth and pluripotency of mouse embryonic stem cells. Leukaemia Inhibitory Factor (LIF) was encapsulated in biodegradable nanoparticles and targeted to the cell surface using an antibody to the oligosaccharide antigen SSEA-1. Sustained release of LIF from nanoparticles composed of a solid Poly(lactide-co-glycolic acid) polyester or a hydrogel-based liposomal system, we term Nanolipogel, replenished once after each cell passage, proved as effective as daily replenishment with soluble LIF for maintenance of pluripotency after 5 passages using 104-fold less LIF. Our study constitutes an alternative paradigm for stem cell culture, providing dynamic microenvironmental control of extrinsic bioactive factors benefiting stem cell manufacturing

DNA Dendrimers Localize Myod mRNA in Presomitic Tissues of the Chick Embryo

MyoD expression is thought to be induced in somites in response to factors released by surrounding tissues; however, reverse transcription-PCR and cell culture analyses indicate that myogenic cells are present in the embryo before somite formation. Fluorescently labeled DNA dendrimers were used to identify MyoD expressing cells in presomitic tissues in vivo. Subpopulations of MyoD positive cells were found in the segmental plate, epiblast, mesoderm, and hypoblast. Directly after laying, the epiblast of the two layered embryo contained ∼20 MyoD positive cells. These results demonstrate that dendrimers are precise and sensitive reagents for localizing low levels of mRNA in tissue sections and whole embryos, and that cells with myogenic potential are present in the embryo before the initiation of gastrulation

Human CD34+/CD90+ ASCs Are Capable of Growing as Sphere Clusters, Producing High Levels of VEGF and Forming Capillaries

Background: Human adult adipose tissue is an abundant source of mesenchymal stem cells (MSCs). Moreover, it is an easily accessible site producing a considerable amount of stem cells. Methodology/Principal Findings: In this study, we have selected and characterized stem cells within the stromal vascular fraction (SVF) of human adult adipose tissue with the aim of understanding their differentiation capabilities and performance. We have found, within the SVF, different cell populations expressing MSC markers – including CD34, CD90, CD29, CD44, CD105, and CD117 – and endothelial-progenitor-cell markers – including CD34, CD90, CD44, and CD54. Interestingly, CD34+/CD90+ cells formed sphere clusters, when placed in non-adherent growth conditions. Moreover, they showed a high proliferative capability, a telomerase activity that was significantly higher than that found in differentiated cells, and contained a fraction of cells displaying the phenotype of a side population. When cultured in adipogenic medium, CD34+/CD90+ quickly differentiated into adipocytes. In addition, they differentiated into endothelial cells (CD31+/VEGF+/Flk- 1+) and, when placed in methylcellulose, were capable of forming capillary-like structures producing a high level of VEGF, as substantiated with ELISA tests. Conclusions/Significance: Our results demonstrate, for the first time, that CD34+/CD90+ cells of human adipose tissue are capable of forming sphere clusters, when grown in free-floating conditions, and differentiate in endothelial cells that form capillary-like structures in methylcellulose. These cells might be suitable for tissue reconstruction in regenerative medicine, especially when patients need treatments for vascular disease