Collagen-hyaluronic acid scaffolds for adipose tissue engineering.

Three-dimensional (3-D) in vitro models of the mammary gland require a scaffold matrix that supports the development of adipose stroma within a robust freely permeable matrix. 3-D porous collagen-hyaluronic acid (HA: 7.5% and 15%) scaffolds were produced by controlled freeze-drying technique and crosslinking with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride. All scaffolds displayed uniform, interconnected pore structure (total porosity approximately 85%). Physical and chemical analysis showed no signs of collagen denaturation during the formation process. The values of thermal characteristics indicated that crosslinking occurred and that its efficiency was enhanced by the presence of HA. Although the crosslinking reduced the swelling of the strut material in water, the collagen-HA matrix as a whole tended to swell more and show higher dissolution resistance than pure collagen samples. The compressive modulus and elastic collapse stress were higher for collagen-HA composites. All the scaffolds were shown to support the proliferation and differentiation 3T3-L1 preadipocytes while collagen-HA samples maintained a significantly increased proportion of cycling cells (Ki-67+). Furthermore, collagen-HA composites displayed significantly raised Adipsin gene expression with adipogenic culture supplementation for 8 days vs. control conditions. These results indicate that collagen-HA scaffolds may offer robust, freely permeable 3-D matrices that enhance mammary stromal tissue development in vitro.This was supported by the Biotechnology and Biological Sciences Research Council

The timing of the formation and usage of replicase clusters in S-phase nuclei of human diploid fibroblasts

The sites of nascent DNA synthesis were compared with the distribution of the proliferating cell nuclear antigen (PCNA) in S-phase nuclei of human diploid fibroblasts (HDF) by two in vitro techniques. Firstly, proliferating fibroblasts growing in culture that had been synchronised at S-phase were microinjected with the thymidine analogue biotin-11-dUTP. The sites of incorporation of biotin into injected cells were compared with the distribution of PCNA by indirect immunofluorescence microscopy and laser scanning confocal microscopy (LSCM). In common with other studies, a progression of patterns for both biotin incorporation and PCNA localisation was observed. However, we did not always observe coincidence in these patterns, the pattern of biotin incorporation often resembling the expected, preceding distribution of PCNA. In nuclei in which the pattern of biotin incorporation appeared to be identical to the distribution of PCNA, LSCM revealed that not all of the sites of PCNA immunofluorescence were incorporating biotin at the same time. Secondly, nuclei which had been isolated from quiescent cultures of HDF were innoculated into cell-free extracts of Xenopus eggs which support DNA replication in vitro. Following innoculation into these extracts DNA replication was initiated in each nucleus. The sites of DNA synthesis were detected by biotin-11-dUTP incorporation and compared with the distribution of PCNA by indirect immunofluorescence. Only a single pattern of biotin incorporation and PCNA distribution was observed. PCNA accumulated at multiple discrete spots some 15min before any biotin incorporation was observed. When biotin incorporation did occur, LSCM revealed almost complete coincidence between the sites of DNA synthesis and the sites at which PCNA was localised.Brunel Open Access Publishing Fun

The Chemistry of Relations: The periodic table examined through the lens of C.S. Peirce’s philosophy.

This thesis explores Charles Peirce’s reception of Dmitri Mendeleev’s periodic arrangement of the chemical elements, the further impact of chemistry on Peirce’s philosophy, such as his phenomenology and diagrammatic reasoning, and the relations between Peirce's theory of iconicity and Mendeleev's periodic table. It is prompted by the almost complete absence in the literature of any discussion of Peirce’s unpublished chemistry manuscripts and the lack of attention given to the connections between Peirce’s early study of chemistry and his later philosophy. This project seeks to make a contribution to this otherwise neglected area of Peirce scholarship

Effective Behavior Change Techniques in Asthma Self-Care Interventions: Systematic Review and Meta-Regression

This article may not exactly replicate the final version published in the APA journal. It is not the copy of record.APA Journals®Objectives: The purpose of this study is to update previous systematic reviews of interventions targeting asthma self-care in adults with asthma, and to use meta-regression to examine the association between the use of specific behavior change techniques and intervention effectiveness. Methods: Electronic bibliographies were searched systematically to identify randomized controlled trials of interventions targeting asthma self-care. Intervention content was coded using a published taxonomy of behavior change techniques. For trials with a low-to-moderate risk of bias, study outcomes were pooled using random effects meta-analysis. Associations between intervention content and effect size were explored using meta-regression. Results: Meta-analysis of 38 trials (7883 patients) showed that interventions targeting asthma self-care reduced symptoms (standardized mean difference [SMD] = -0.38 [-0.52, -0.24]) and unscheduled health care use (odds ratio [OR] = 0.71 [0.56 to 0.90]) and increased adherence to preventive medication (OR = 2.55 [2.11 to 3.10]). meta-regression analyses found that "active involvement of participants" was associated with a reduction in unscheduled health care use (OR = 0.50 vs. 0.79). Inclusion of "stress management" techniques was associated with an increase in asthma symptoms (SMD = 0.01 vs. -0.44). Existing recommendations about the "optimal" content of asthma self-care interventions were tested but were not supported by the data. Conclusions: Interventions targeting asthma self-care are effective. Active involvement of participants is associated with increased intervention effectiveness, but the use of stress management techniques may be counterproductive. Taxonomy-based systematic reviews using meta-regression have potential for identifying techniques associated with increased effectiveness in behavioral interventions. (PsycINFO Database Record (c) 2013 APA, all rights reserved)

Development of three-dimensional collagen scaffolds with controlled architecture for cell migration studies using breast cancer cell lines

Cancer is characterized by cell heterogeneity and the development of 3D $\textit{in vitro }$ assays that can distinguish more invasive or migratory phenotypes could enhance diagnosis or drug discovery. 3D collagen scaffolds have been used to develop analogues of complex tissues $\textit{in vitro }$ and are suited to routine biochemical and immunological assays. We sought to increase 3D model tractability and modulate the migration rate of seeded cells using an ice-templating technique to create either directional/anisotropic or non-directional/isotropic porous architectures within cross-linked collagen scaffolds. Anisotropic scaffolds supported the enhanced migration of an invasive breast cancer cell line MDA-MB-231 with an altered spatial distribution of proliferative cells in contrast to invasive MDA-MB-468 and non-invasive MCF-7 cells lines. In addition, MDA-MB-468 showed increased migration upon epithelial-to-mesenchymal transition (EMT) in anisotropic scaffolds. The provision of controlled architecture in this system may act both to increase assay robustness and as a tuneable parameter to capture detection of a migrated population within a set time, with consequences for primary tumour migration analysis. The separation of invasive clones from a cancer biomass with in vitro platforms could enhance drug development and diagnosis testing by contributing assay metrics including migration rate, as well as modelling cell-cell and cell-matrix interaction in a system compatible with routine histopathological testing.The authors gratefully acknowledge the financial support of the ERC Advanced Grant 320598 3D-E and the Newton Trust. A.H. held a Daphne Jackson Fellowship funded by the University of Cambridge for part of the work. R.D.H. is funded through a NC3Rs studentship

Synapses formed by identified retinogeniculate axons during the segregation of eye input.

The synaptic organization of identified retinogeniculate axons was studied during the prenatal development of eye-specific layers in the LGN of the cat. During this period, retinogeniculate axons undergo stereotyped morphological changes. Retinogeniculate axons originating from one eye and passing through LGN territory destined to be solely innervated by the other eye (inappropriate territory) initially give rise to many side branches. As the eye-specific layers emerge, these axons elaborate extensive terminal arbors within territory appropriate to their eye of origin and concurrently retract their side branches from inappropriate territory (Sretavan and Shatz, 1986). These transient side branches may therefore represent a morphological substrate for the observed functional convergence of inputs from the two eyes onto common LGN neurons during prenatal development (Shatz and Kirkwood, 1984). This possibility was investigated by examining whether identified axons and their side branches form synapses in inappropriate territory. Three retinogeniculate axons from two fetuses aged embryonic day 53 (E53) and E57 were filled with HRP in an in vitro preparation, prior to being processed for electron microscopy (EM). The HRP-filled axons, originating from the contralateral eye, were first reconstructed at the light microscope level. The portion of axon passing through the center of ipsilaterally innervated layer A1 was then serially sectioned and reconstructed by EM. Two sets of 450 serial EM sections revealed that all three contralateral axons established synaptic contacts in ipsilateral territory. Many of these synapses were made by side branches and a few were even formed by the main axon trunks. Both side branches and trunks formed mainly en passant asymmetrical contacts that were associated with spherical synaptic vesicles and that were apposed to immature dendritic elements and dendritic shafts. For comparison, a portion of the same E53 axon within the future contralateral layer A was also serially sectioned and reconstructed for EM. Within this contralateral zone, the E53 axon formed synaptic contacts similar to those established in the ipsilateral region, except that in the appropriate zone they contained significantly more synaptic vesicles. These results demonstrate that axons from the contralateral eye can establish synapses in territory simultaneously innervated by the ipsilateral eye, both via side branches and by means of contacts along the main axon trunk. Thus, the development of eye-specific layers is accompanied by the formation and subsequent elimination of synapses that almost certainly represent a morphological substrate for the known transient functional convergence of inputs from the two eyes

Gluon fusion contribution to W+W- + jet production

We describe the computation of the $gg \to W^+W^-g$ process that contributes to the production of two $W$-bosons and a jet at the CERN Large Hadron Collider (LHC). While formally of next-to-next-to-leading order (NNLO) in QCD, this process can be evaluated separately from the bulk of NNLO QCD corrections because it is finite and gauge-invariant. It is also enhanced by the large gluon flux and by selection cuts employed in the Higgs boson searches in the decay channel $H \to W^+W^-$, as was first pointed out by Binoth {\it et al.} in the context of $gg \to W^+W^-$ production. For cuts employed by the ATLAS collaboration, we find that the gluon fusion contribution to $pp \to W^+W^-j$ enhances the background by about ten percent and can lead to moderate distortions of kinematic distributions which are instrumental for the ongoing Higgs boson searches at the LHC. We also release a public code to compute the NLO QCD corrections to this process, in the form of an add-on to the package {\tt MCFM}.Comment: 13 pages, 4 figures, 3 table

CancerGD: A Resource for Identifying and Interpreting Genetic Dependencies in Cancer.

Genes whose function is selectively essential in the presence of cancer-associated genetic aberrations represent promising targets for the development of precision therapeutics. Here, we present CancerGD, a resource that integrates genotypic profiling with large-scale loss-of-function genetic screens in tumor cell lines to identify such genetic dependencies. CancerGD provides tools for searching, visualizing, and interpreting these genetic dependencies through the integration of functional interaction networks. CancerGD includes different screen types (siRNA, shRNA, CRISPR), and we describe a simple format for submitting new datasets

Circulating endothelial cell-derived extracellular vesicles mediate the acute phase response and sickness behaviour associated with CNS inflammation.

Brain injury elicits a systemic acute-phase response (APR), which is responsible for co-ordinating the peripheral immunological response to injury. To date, the mechanisms responsible for signalling the presence of injury or disease to selectively activate responses in distant organs were unclear. Circulating endogenous extracellular vesicles (EVs) are increased after brain injury and have the potential to carry targeted injury signals around the body. Here, we examined the potential of EVs, isolated from rats after focal inflammatory brain lesions using IL-1β, to activate a systemic APR in recipient naïve rats, as well as the behavioural consequences of EV transfer. Focal brain lesions increased EV release, and, following isolation and transfer, the EVs were sequestered by the liver where they initiated an APR. Transfer of blood-borne EVs from brain-injured animals was also enough to suppress exploratory behaviours in recipient naïve animals. EVs derived from brain endothelial cell cultures treated with IL-1β also activated an APR and altered behaviour in recipient animals. These experiments reveal that inflammation-induced circulating EVs derived from endothelial cells are able to initiate the APR to brain injury and are sufficient to generate the associated sickness behaviours, and are the first demonstration that EVs are capable of modifying behavioural responses

{\phi}^4 Solitary Waves in a Parabolic Potential: Existence, Stability, and Collisional Dynamics

We explore a {\phi}^4 model with an added external parabolic potential term. This term dramatically alters the spectral properties of the system. We identify single and multiple kink solutions and examine their stability features; importantly, all of the stationary structures turn out to be unstable. We complement these with a dynamical study of the evolution of a single kink in the trap, as well as of the scattering of kink and anti-kink solutions of the model. We see that some of the key characteristics of kink-antikink collisions, such as the critical velocity and the multi-bounce windows, are sensitively dependent on the trap strength parameter, as well as the initial displacement of the kink and antikink