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Uncertainties in tidally adjusted estimates of sea level rise flooding (bathtub model) for the Greater London
Sea-level rise (SLR) from global warming may have severe consequences for coastal cities,
particularly when combined with predicted increases in the strength of tidal surges. Predicting the
regional impact of SLR ïŹooding is strongly dependent on the modelling approach and accuracy
of topographic data. Here, the areas under risk of sea water ïŹooding for London boroughs were
quantiïŹed based on the projected SLR scenarios reported in Intergovernmental Panel on Climate
Change (IPCC) ïŹfth assessment report (AR5) and UK climatic projections 2009 (UKCP09) using a
tidally-adjusted bathtub modelling approach. Medium- to very high-resolution digital elevation
models (DEMs) are used to evaluate inundation extents as well as uncertainties. Depending on the
SLR scenario and DEMs used, it is estimated that 3%â8% of the area of Greater London could be
inundated by 2100. The boroughs with the largest areas at risk of ïŹooding are Newham, Southwark,
and Greenwich. The differences in inundation areas estimated from a digital terrain model and a
digital surface model are much greater than the root mean square error differences observed between
the two data types, which may be attributed to processing levels. Flood models from SRTM data
underestimate the inundation extent, so their results may not be reliable for constructing ïŹood
risk maps. This analysis provides a broad-scale estimate of the potential consequences of SLR and
uncertainties in the DEM-based bathtub type ïŹood inundation modelling for London boroughs
The phase diagram of the API benzocaine and its highly persistent, metastable crystalline polymorphs
The availability of sufficient amounts of form I of benzocaine has led to the investigation of its phase relationships with the other two existing forms, II and III, using adiabatic calorimetry, powder X-ray diffraction, and high-pressure differential thermal analysis. The latter two forms were known to have an enantiotropic phase relationship in which form III is stable at low-temperatures and high-pressures, while form II is stable at room temperature with respect to form III. Using adiabatic calorimetry data, it can be concluded, that form I is the stable low-temperature, high-pressure form, which also happens to be the most stable form at room temperature; however, due to its persistence at room temperature, form II is still the most convenient polymorph to use in formulations. Form III presents a case of overall monotropy and does not possess any stability domain in the pressureâtemperature phase diagram. Heat capacity data for benzocaine have been obtained by adiabatic calorimetry from 11 K to 369 K above its melting point, which can be used to compare to results from in silico crystal structure prediction.Peer ReviewedPostprint (published version
Absence of molecular mobility on nano-second time scales in amorphous ice phases
High-resolution neutron backscattering techniques are exploited to study the
elastic and quasi-elastic response of the high-density amorphous (HDA), the
low-density amorphous (LDA) and the crystalline ice Ic upon temperature
changes. Within the temperature ranges of their structural stability (HDA at T
> 80 K, LDA at T > 135 K, ice Ic at T < 200 K) the Debye-Waller factors and
mean-square displacements characterise all states as harmonic solids. During
the transformations HDA->LDA (T ~ 100 K), LDA->Ic (T ~ 150K) and the supposed
glass transition with Tg ~ 135 K no relaxation processes can be detected on a
time scale t < 4 ns. It can be concluded from coherent scattering measurements
(D_2O) that LDA starts to recrystallise into ice Ic at T ~ 135 K, i.e. at the
supposed Tg. In the framework of the Debye model of harmonic solids HDA reveals
the highest Debye temperature among the studied ice phases, which is in full
agreement with the lowest Debye level in the generalised density of states
derived from time-of-flight neutron scattering experiments. The elastic results
at low T indicate the presence of an excess of modes in HDA, which do not obey
the Bose statistics
The relationship between fragility, configurational entropy and the potential energy landscape of glass forming liquids
Glass is a microscopically disordered, solid form of matter that results when
a fluid is cooled or compressed in such a fashion that it does not crystallise.
Almost all types of materials are capable of glass formation -- polymers, metal
alloys, and molten salts, to name a few. Given such diversity, organising
principles which systematise data concerning glass formation are invaluable.
One such principle is the classification of glass formers according to their
fragility\cite{fragility}. Fragility measures the rapidity with which a
liquid's properties such as viscosity change as the glassy state is approached.
Although the relationship between features of the energy landscape of a glass
former, its configurational entropy and fragility have been analysed previously
(e. g.,\cite{speedyfr}), an understanding of the origins of fragility in these
features is far from being well established. Results for a model liquid, whose
fragility depends on its bulk density, are presented in this letter. Analysis
of the relationship between fragility and quantitative measures of the energy
landscape (the complicated dependence of energy on configuration) reveal that
the fragility depends on changes in the vibrational properties of individual
energy basins, in addition to the total number of such basins present, and
their spread in energy. A thermodynamic expression for fragility is derived,
which is in quantitative agreement with {\it kinetic} fragilities obtained from
the liquid's diffusivity.Comment: 8 pages, 3 figure
Harmonic Vibrational Excitations in Disordered Solids and the "Boson Peak"
We consider a system of coupled classical harmonic oscillators with spatially
fluctuating nearest-neighbor force constants on a simple cubic lattice. The
model is solved both by numerically diagonalizing the Hamiltonian and by
applying the single-bond coherent potential approximation. The results for the
density of states are in excellent agreement with each other. As
the degree of disorder is increased the system becomes unstable due to the
presence of negative force constants. If the system is near the borderline of
stability a low-frequency peak appears in the reduced density of states
as a precursor of the instability. We argue that this peak
is the analogon of the "boson peak", observed in structural glasses. By means
of the level distance statistics we show that the peak is not associated with
localized states
Theoretical Evaluation of the Reaction Rates for 26Al(n,p)26Mg and 26Al(n,a)23Na
The reactions that destroy 26Al in massive stars have significance in a
number of astrophysical contexts. We evaluate the reaction rates of
26Al(n,p)26Mg and 26Al(n,a)23Na using cross sections obtained from the codes
EMPIRE and TALYS. These have been compared to the published rates obtained from
the non-smoker code and to some experimental data. We show that the results
obtained from EMPIRE and TALYS are comparable to those from non-smoker. We also
show how the theoretical results vary with respect to changes in the input
parameters. Finally, we present recommended rates for these reactions using the
available experimental data and our new theoretical results
Entropy Crisis, Ideal Glass Transition and Polymer Melting: Exact Solution on a Husimi Cactus
We introduce an extension of the lattice model of melting of semiflexible
polymers originally proposed by Flory. Along with a bending penalty, present in
the original model and involving three sites of the lattice, we introduce an
interaction energy that corresponds to the presence of a pair of parallel bonds
and a second interaction energy associated with the presence of a hairpin turn.
Both these new terms represent four-site interactions. The model is solved
exactly on a Husimi cactus, which approximates a square lattice. We study the
phase diagram of the system as a function of the energies. For a proper choice
of the interaction energies, the model exhibits a first-order melting
transition between a liquid and a crystalline phase. The continuation of the
liquid phase below this temperature gives rise to a supercooled liquid, which
turns continuously into a new low-temperature phase, called metastable liquid.
This liquid-liquid transition seems to have some features that are
characteristic of the critical transition predicted by the mode-coupling
theory.Comment: To be published in Physical Review E, 68 (2) (2003
A DEMETER-like DNA demethylase protein governs tomato fruit ripening
In plants, genomic DNA methylation which contributes to development and stress responses can be actively removed by DEMETER-like DNA demethylases (DML). Indeed, in Arabidopsis DMLs are important for maternal imprinting and endosperm demethylation, but only few studies demonstrate the developmental roles of active DNA demethylation conclusively in this plant. Here we show a direct cause and effect relationship between active DNA demethylation mainly mediated by the tomato DML, SlDML2, and fruit ripening; an important developmental process unique to plants. RNAi SlDML2 knock-down results in ripening inhibition via hypermethylation and repression of the expression of genes encoding ripening transcription factors and rate-limiting enzymes of key biochemical processes such as carotenoid synthesis. Our data demonstrate that active DNA demethylation is central to the control of ripening in tomat
Apoptosis, autophagy and ER stress in mevalonate cascade inhibition-induced cell death of human atrial fibroblasts
3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors (statins) are cholesterol-lowering drugs that exert other cellular effects and underlie their beneficial health effects, including those associated with myocardial remodeling. We recently demonstrated that statins induces apoptosis and autophagy in human lung mesenchymal cells. Here, we extend our knowledge showing that statins simultaneously induces activation of the apoptosis, autophagy and the unfolded protein response (UPR) in primary human atrial fibroblasts (hATF). Thus we tested the degree to which coordination exists between signaling from mitochondria, endoplasmic reticulum and lysosomes during response to simvastatin exposure. Pharmacologic blockade of the activation of ER-dependent cysteine-dependent aspartate-directed protease (caspase)-4 and lysosomal cathepsin-B and -L significantly decreased simvastatin-induced cell death. Simvastatin altered total abundance and the mitochondrial fraction of proapoptotic and antiapoptotic proteins, while c-Jun N-terminal kinase/stress-activated protein kinase mediated effects on B-cell lymphoma 2 expression. Chemical inhibition of autophagy flux with bafilomycin-A1 augmented simvastatin-induced caspase activation, UPR and cell death. In mouse embryonic fibroblasts that are deficient in autophagy protein 5 and refractory to autophagy induction, caspase-7 and UPR were hyper-induced upon treatment with simvastatin. These data demonstrate that mevalonate cascade inhibition-induced death of hATF manifests from a complex mechanism involving co-regulation of apoptosis, autophagy and UPR. Furthermore, autophagy has a crucial role in determining the extent of ER stress, UPR and permissiveness of hATF to cell death induced by statins
Apelin Deficiency Accelerates the Progression of Amyotrophic Lateral Sclerosis
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the selective loss of motor neurons. Recent studies have implicated that chronic hypoxia and insufficient vascular endothelial growth factor (VEGF)-dependent neuroprotection may lead to the degeneration of motor neurons in ALS. Expression of apelin, an endogenous ligand for the G protein-coupled receptor APJ, is regulated by hypoxia. In addition, recent reports suggest that apelin protects neurons against glutamate-induced excitotoxicity. Here, we examined whether apelin is an endogenous neuroprotective factor using SOD1G93A mouse model of ALS. In mouse CNS tissues, the highest expressions of both apelin and APJ mRNAs were detected in spinal cord. APJ immunoreactivity was observed in neuronal cell bodies located in gray matter of spinal cord. Although apelin mRNA expression in the spinal cord of wild-type mice was not changed from 4 to 18 weeks age, that of SOD1G93A mice was reduced along with the paralytic phenotype. In addition, double mutant apelin-deficient and SOD1G93A displayed the disease phenotypes earlier than SOD1G93A littermates. Immunohistochemical observation revealed that the number of motor neurons was decreased and microglia were activated in the spinal cord of the double mutant mice, indicating that apelin deficiency pathologically accelerated the progression of ALS. Furthermore, we showed that apelin enhanced the protective effect of VEGF on H2O2-induced neuronal death in primary neurons. These results suggest that apelin/APJ system in the spinal cord has a neuroprotective effect against the pathogenesis of ALS
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