864 research outputs found
Spectral fluctuations of tridiagonal random matrices from the beta-Hermite ensemble
A time series delta(n), the fluctuation of the nth unfolded eigenvalue was
recently characterized for the classical Gaussian ensembles of NxN random
matrices (GOE, GUE, GSE). It is investigated here for the beta-Hermite ensemble
as a function of beta (zero or positive) by Monte Carlo simulations. The
fluctuation of delta(n) and the autocorrelation function vary logarithmically
with n for any beta>0 (1<<n<<N). The simple logarithmic behavior reported for
the higher-order moments of delta(n) for the GOE (beta=1) and the GUE (beta=2)
is valid for any positive beta and is accounted for by Gaussian distributions
whose variances depend linearly on ln(n). The 1/f noise previously demonstrated
for delta(n) series of the three Gaussian ensembles, is characterized by
wavelet analysis both as a function of beta and of N. When beta decreases from
1 to 0, for a given and large enough N, the evolution from a 1/f noise at
beta=1 to a 1/f^2 noise at beta=0 is heterogeneous with a ~1/f^2 noise at the
finest scales and a ~1/f noise at the coarsest ones. The range of scales in
which a ~1/f^2 noise predominates grows progressively when beta decreases.
Asymptotically, a 1/f^2 noise is found for beta=0 while a 1/f noise is the rule
for beta positive.Comment: 35 pages, 10 figures, corresponding author: G. Le Cae
\u3ci\u3eThemeda triandra\u3c/i\u3e as a Perennial Seed Crop in South-Eastern Australia: What are the Agronomic Possibilities and Constraints, and Future Research Needs?
In Australia, the development of native perennial seed crops is an area of increasing interest. Reasons for this include the production of high-value seed, the significance of native plants to Aboriginal people and the importance of diversified cropping in building more resilient farming systems. One species of interest is Themeda triandra, a C4 perennial tussock grass that dominated grasslands and woodlands across Australia prior to European invasion. Djaara, the traditional owner group representing the Dja Dja Wurrung people of Djandak (Dja Dja Wurrung country in central Victoria), is one group who seek to return T. triandra to the landscape as a seed-producing crop. This is due to the species holding for them significant cultural and social value, along with envisioned future economic opportunities. As such, this review is targeted towards temperate grasslands of south-eastern Australia where Djandak is located. This review summarises the agronomic possibilities and constraints relating to production of a T. triandra as a seed crop via an understanding of the genetic, environmental and management factors that influence the growth, development, and seed yield of this species. Future research and development needs are also identified
Brain endothelial miR-146a negatively modulates T-cell adhesion through repressing multiple targets to inhibit NF-kappa B activation
Pro-inflammatory cytokine-induced activation of nuclear factor, NF-κB has an important role in leukocyte adhesion to, and subsequent migration across, brain endothelial cells (BECs), which is crucial for the development of neuroinflammatory disorders such as multiple sclerosis (MS). In contrast, microRNA-146a (miR-146a) has emerged as an anti-inflammatory molecule by inhibiting NF-κB activity in various cell types, but its effect in BECs during neuroinflammation remains to be evaluated. Here, we show that miR-146a was upregulated in microvessels of MS-active lesions and the spinal cord of mice with experimental autoimmune encephalomyelitis. In vitro, TNFα and IFNγ treatment of human cerebral microvascular endothelial cells (hCMEC/D3) led to upregulation of miR-146a. Brain endothelial overexpression of miR-146a diminished, whereas knockdown of miR-146a augmented cytokine-stimulated adhesion of T cells to hCMEC/D3 cells, nuclear translocation of NF-κB, and expression of adhesion molecules in hCMEC/D3 cells. Furthermore, brain endothelial miR-146a modulates NF-κB activity upon cytokine activation through targeting two novel signaling transducers, RhoA and nuclear factor of activated T cells 5, as well as molecules previously identified, IL-1 receptor-associated kinase 1, and TNF receptor-associated factor 6. We propose brain endothelial miR-146a as an endogenous NF-κB inhibitor in BECs associated with decreased leukocyte adhesion during neuroinflammation. </p
Numerical reconstruction of brain tumours
We propose a nonlinear Landweber method for the inverse problem of locating the brain tumour source (origin where the tumour formed) based on well-established models of reaction–diffusion type for brain tumour growth. The approach consists of recovering the initial density of the tumour cells starting from a later state, which can be given by a medical image, by running the model backwards. Moreover, full three-dimensional simulations are given of the tumour source localization on two types of data, the three-dimensional Shepp–Logan phantom and an MRI T1-weighted brain scan. These simulations are obtained using standard finite difference discretizations of the space and time derivatives, generating a simple approach that performs well
Pharmacology of enalapril in children: a review
Enalapril is an angiotensin-converting enzyme (ACE) inhibitor that is used for the treatment of (paediatric) hypertension, heart failure and chronic kidney diseases. Because its disposition, efficacy and safety differs across the paediatric continuum, data from adults cannot be automatically extrapolated to children. This review highlights paediatric enalapril pharmacokinetic data and demonstrates that these are inadequate to support with certainty an age-related effect on enalapril/enalaprilat pharmacokinetics. In addition, our review shows that evidence to support effective and safe prescribing of enalapril in children is limited, especially in young children and heart failure patients; studies in these groups are either absent or show conflicting results. We provide explanations for observed differences between age groups and indications, and describe areas for future research
Design management: changing roles of the professions
This paper sets out to explore how recent changes in
procurement in construction have affected the roles that
professions play in the design process. It discusses how
professions that traditionally took the role of design
manager now find themselves participating within
previously unforeseen contexts, working in multidisciplinary
teams led by contractors and with changed
responsibilities at the design stage. Supply chain members
who were not previously involved during the early project
phases are being engaged at the earliest phases of the
project life cycle and even taking leadership roles while
designers sometimes work as supply chain partners.
A study of design in construction and other sectors shows
that in dealing with design management issues it is critical
to deepen appreciation for the unique characteristics of
design and the design process. The paper argues that
contractors and designers taking on design management
roles in a dynamic industry seeking to explore best
practice and innovative approaches to procurement and in
the delivery of projects need to acquire new skills,
management education and develop the necessary
qualities
Influence of Terminal Functionality on the Crystal Packing Behaviour and Cytotoxicity of Aromatic Oligoamides
YesThe synthesis and characterization of three aromatic oligoamides, constructed from the same pyridyl carboxamide core but incorporating distinct end groups of acetyl (Ac) 1, tert-butyloxycarbonyl (Boc) 2 and amine 3 is reported. Single crystal X-ray diffraction analysis of 1-3 and a dimethylsulfoxide (DMSO) solvate of 2 (2-DMSO), has identified the presence of a range of intra- and intermolecular interactions including N-H⋯N, N-H⋯O=C and N-H⋯O=S(CH3)2 hydrogen-bonding interactions, C-H⋯π interactions and off-set, face-to-face stacking π-π interactions that support the variety of slipped stack, herringbone and cofacial crystal packing arrangements observed in 1-3. Additionally, the cytotoxicity of this series of aromatic oligoamides was assessed against two human ovarian (A2780 and A2780cisR), two human breast (MCF-7 and MDA-MB-231) cancerous cell lines and one non-malignant human epithelial cell line (PNT-2), to investigate the influence of the terminal functionality of these aromatic oligoamides on their biological activity. The chemosensitivity results highlight that modification of the terminal group from Ac to Boc in 1 and 2 leads to a 3-fold increase in antiproliferative activity against the cisplatin-sensitive ovarian carcinoma cell line, A2780. The presence of the amine termini in 3 gave the only member of the series to display activity against the cisplatin-resistance ovarian carcinoma cell line, A2780cisR. Compound 2 is the lead candidate of this series, displaying high selectivity towards A2780 cancer cells when compared to non-malignant PNT-2 cells, with a selectivity index value >4.2. Importantly, this compound is more selective towards A2780 (cf. PNT-2) than the clinical platinum drugs oxaliplatin by > 2.6-fold and carboplatin by > 1.6-fold.University of Bradford Development Fund; University of Birmingham - Birmingham Fellowship; UKRI Future Leaders Fellowship (MR/T041315/1); UKRI Future Leaders Fellowship (MR/S035486/2
Pharmacotherapeutic management of paediatric heart failure and ACE-I use patterns: A European survey
Objective To characterise heart failure (HF) maintenance
pharmacotherapy for children across Europe and
investigate how angiotensin-converting enzyme inhibitors
(ACE-I) are used in this setting.
Methods A Europe-wide web-based survey was
conducted between January and May 2015 among
European paediatricians dedicated to cardiology.
Results Out of 200-eligible, 100 physicians representing
100 hospitals in 27 European countries participated. All
participants reported prescribing ACE-I to treat dilated
cardiomyopathy-related HF and 97% in the context of
congenital heart defects; 87% for single ventricle physiology.
Twenty-six per cent avoid ACE-I i
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