bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bending strength properties of untreated and impregnated igneous, sedimentary and metamorphic dimension stones of different thickness
Authors: Sahlin T. , Stigh J. , Schouenborg B. 
Published: September 2007

Abstract
A production method has been developed that makes it possible to produce dimension stone tiles only 4 mm thick without high amounts of waste material. The tiles are impregnated with a mixture of potassium-based water-glass, water, colloidal silica, and Berol 048 (non-ionic surfactant), using a repeated cycling between vacuum and atmospheric pressure. Mineralogy, fabric, and porosity affect the mechanical properties of rock used as dimension stone in the building industry. Tests for bending strength have been performed on tiles of eight different untreated and impregnated samples of igneous, sedimentary, and metamorphic rocks. Samples of three different thicknesses (4, 7 and 10 mm) were used in the tests. The untreated rock samples that had a fine-grained texture, low crack density, high mafic mineral content or a distinct ductile metamorphic texture showed the highest bending strength values, whereas those that had high amounts of carbonate minerals, and high crack or void density exhibited the lowest values. The stone types that gained the most from impregnation, in general, were those with high crack or void density.
Atmospheric pollution and building materials: stone and glass
Authors: Lefèvre R. A. , Ausset P. 
Published: September 2007

Abstract
The research carried out by LISA on the decay of stone and glass by atmospheric pollution is presented. On building facades, areas unsheltered from rain are clear and eroded, while those that are sheltered darken due to the development of black crusts containing anthropogenic particles (fly-ash, soot) cemented by a framework of gypsum crystals. On calcareous stones, in-depth sulphation of the stone substrate may also occur at the same time. On porous calcareous stones, the black crusts detach periodically forming black slabs, creating a white, grey and black jigsaw-like pattern on the remaining stone surface. By exposing stone test samples to field and/or laboratory controlled polluted atmospheric conditions, the formation of embryonic black crusts has been observed. Grey crusts developed during pre-industrial times have been found to contain unburnt wood debris as a record of past air pollution. Glass alters by leaching, corrosion, encrusting and soiling. The quantification of the effects of atmospheric pollution can be accomplished either directly on buildings of different ages, or through field and/or laboratory controlled experiments. Modelling of the alteration of materials by atmospheric pollution consists of the determination of dose-response functions, of acceptable levels and thresholds and in risk assessment mapping.
Modelling the rapid retreat of building sandstones: a case study from a polluted maritime environment
Authors: Smith B. J. , Turkington A. V. , Warke P. A. , Basheer P. A. M. , McAlister J. J. , Meneely J. , Curran J. M. 
Published: September 2007

Abstract
Sandstones are widely used as building stones throughout NW Europe. Unlike limestone, sandstones tend to experience episodic and sometimes rapid surface retreat associated with the action of salts and often leading to the development of hollows/caverns in the stone. The unpredictability of these decay dynamics can present significant problems when planning conservation strategies. Consequently, successful conservation requires a better understanding of the factors that trigger decay and determine the subsequent decay pathway. An overview of results from previous studies provided the basis for simulation experiments aimed at identifying the factors that (a) initiate decay and (b) permit the continuance of salt weathering despite rapid loss of surface material. These simulation studies involve investigation of changes in micro-environmental conditions as surface hollows develop and examination of salt weathering dynamics within such hollows. These data combined with knowledge gained from previous work have allowed the refinement of a conceptual model of rapid sandstone retreat. In this model decay is linked to the establishment of positive feedback conditions through interactions between factors such as porosity, permeability, mineralogy and their effect on salt penetration.
Oolitic limestone in a polluted atmospheric environment in Budapest: weathering phenomena and alterations in physical properties
Authors: Török Ákos 
Published: September 2007

Abstract

In Budapest damage due to atmospheric pollution on many public buildings is severe. Black encrustations, white crusts and other decay features of a soft oolitic limestone have been studied in detail by using field measurements and laboratory analyses. Limestone weathering was assessed by description of weathering forms, by on-site petrophysical tests (Duroscope, Schmidt hammer, water absorption) and by laboratory mineralogical assessment and thermoanalysis (X-ray diffraction, Derivatograph). There is a clear correlation between the organic carbon content in stone and location of the site, particularly in the polluted city centre. Gypsum, which is not an indigenous mineral in the limestone, can contribute up to 70% of the crust composition and indicates the importance of air-derived SO
2
. This mineralogical change in stone composition leads to changes in physical properties, by strengthening laminar black crusts and white case hardened crusts and weakening the host rock.
Acid deposition and the deterioration of stone: a brief review of a broad topic
Authors: Charola A. Elena , Ware Robert 
Published: September 2007

Abstract

The causes of stone deterioration due to acid deposition are examined, with specific reference made to important research on this subject from the past thirty years. The major topics covered include: dry deposition of atmospheric pollutants, the primary agent of acid deterioration of stone in urban areas; wet deposition, commonly referred to as acid rain; and major deterioration mechanisms. Key factors are dry deposition of gaseous pollutants such as SO
2
and NOx, the nature of the stone, including texture and porosity, and the presence of moisture on its surface as well as the ‘time of wetness’.
Evaluation of the origin of sulphate compounds in building stone by sulphur isotope ratio
Authors: Klemm Werner , Siedel Heiner 
Published: September 2007

Abstract

Sulphate salts are a main factor in the deterioration of building materials such as natural stone, mortar, plaster and brick. Although environmental pollution is the main source for the formation of sulphate salts on historical monuments in Central Europe, for more detailed investigations into the reasons for salt formation on specific buildings more precise information about the sources and the transport paths is needed. Sulphur isotope analyses seem to be a useful tool for the characterization of various sources of sulphur in the natural as well as in the anthropogenic environment relevant to salt formation on monuments. Investigations in the southern part of East Germany with extreme environmental pollution until 1990 should demonstrate the advantages and limits of the method. Environmental influences are the main factor for sulphate salt formation at historical monuments in this area. In special cases other sources such as groundwater or building materials are relevant for salt formation. At a regional scale, the δ
34
S values for salts and crusts on monuments scatter over a broad range (between +2 and +10‰ in the investigated area). Nevertheless, for special locations or monuments the number of possible sources of sulphur can be minimized if δ
34
S values for all relevant influences such as building materials, groundwater and the specific environmental influences (rainwater, dust, SO
2
) are available.
Kinematics of the East African Rift from GPS and earthquake slip vector data
Authors: Calais E. , Ebinger C. , Hartnady C. , Nocquet J.M. 
Published: September 2007

Abstract
Although the East African Rift (EAR) System is often cited as the archetype for models of continental rifting and break-up, its present-day kinematics remains poorly constrained. We show that the currently available GPS and earthquake slip vector data are consistent with (1) a present-day Nubia-Somalia Euler pole located between the southern tip of Africa and the Southwest Indian ridge and (2) the existence of a distinct microplate (Victoria) between the Eastern and Western rifts, rotating counter-clockwise with respect to Nubia. Geodetic and geological data also suggest the existence of a (Rovuma) microplate between the Malawi rift and the Davie ridge, possibly rotating clockwise with respect to Nubia. The data indicate that the EAR comprises at least two rigid lithospheric blocks bounded by narrow belts of seismicity (<50 km wide) marking localized deformation rather than a wide zone of quasi-continuous, pervasive deformation. On the basis of this new kinematic model and mantle flow directions interpreted from seismic anisotropy measurements, we propose that regional asthenospheric upwelling and locally focused mantle flow may influence continental deformation in East Africa.
Strain accommodation in transitional rifts: extension by magma intrusion and faulting in Ethiopian rift magmatic segments
Authors: Casey M. , Ebinger C. , Keir D. , Gloaguen R. , Mohamed F. 
Published: September 2007

Abstract
Active deformation within the northern part of the Main Ethiopian Rift (MER) occurs within approximately 60 km-long, 20 km-wide ‘magmatic segments’ that lie within the 80 km-wide rift valley. Geophysical data reveal that the crust beneath the <1.9 Ma magmatic segments has been heavily intruded; magmatic segments accommodate strain via both magma intrusion and faulting. We undertake field and remote sensing analyses of faults and eruptive centres in the magmatic segments to estimate the relative proportion of strain accommodated by faulting and magma intrusion and the kinematics of Quaternary faults. Up to half the ≤10 km-long normal faults within the Boset-Kone and Fantale-Dofen magmatic segments have eruptive centres or extrusive lavas along their length. Comparison of the deformation field of the largest Quaternary fault and an elastic half-space dislocation model indicates a down-dip length of 10 km, coincident with the seismogenic layer thickness and the top of the seismically imaged mafic intrusions. These relations suggest that Quaternary faults are primarily driven by magma intrusion into the mid- to upper crust, which triggers faulting and dyke intrusion into the brittle upper crust. The active volcanoes of Boset, Fantale and Dofen all have elliptical shapes with their long axes in the direction N105, consistent with extension direction derived from earthquake focal mechanisms. Calderas show natural strains ranging from around 0.30 for Boset, 0.55 for Fantale, and 0.94 for Dofen. These values give extension strain rates of the order of 0.3 microstrain per year, comparable to geodetic models. Structural analyses reveal no evidence for transcurrent faults linking right-stepping magmatic segments. Instead, the tips of magmatic segments overlap, thereby accommodating strain transfer. The intimate relationship between faulting and magmatism in the northern MER is strikingly similar to that of slow-spreading mid-ocean ridges, but without the hard linkage zones of transform faults.
Vertical deformation in the Main Ethiopian Rift: levelling results in its northern part, 1995–2004
Authors: Asfaw Laike M. , Beyene Henok , Mkonnen Amde , Oli Tadesse 
Published: September 2007

Abstract

A levelling line consisting of 43 benchmarks was established between the towns of Wolenchiti and Metehara in the northern part of the Main Ethiopian Rift in July 1995 by the Geophysical Observatory of Addis Ababa University and the Ethiopian Mapping Authority. The measurement was repeated in November 2003 on 30 of the surviving benchmarks. In both epochs of measurement, the standard accuracy attained is ± 4 mm √K corresponding to a first order levelling, where
K
is the inter-benchmark distance in kilometres. The line crosses the northern and southern parts of the Nazret (Boset-Kone) and Sabure (Fantale-Dofen) magmatic segments respectively where 80% of rift deformation is believed to be localized. In eight years, interval height differences ranging from +3 mm to −22 mm are found along the line with the maximum subsidence rate of 2.8 mm a
−1
corresponding to the Kone-Gariboldi volcanic complex in the northern part of the Nazret magmatic segment. On the other hand, at the eastern end of the line, despite the existence of large fissures and an expanding lake in the vicinity suggesting possible significant subsidence, on the contrary relatively small vertical deformation is found. The strong subsidence measured at the Kone-Gariboldi volcanic complex is interpreted to be due to remnant processes of subsidence at these volcanic centres following withdrawal of magma in the recent past. Regarding the eastern end of the line where Lake Beseka is located, the result is particularly important in verifying that the rapid expansion of the lake associated with elevation increase of 40 cm a
−1
could not be attributed to tectonic subsidence or uplift in the region.
Dynamics of prolonged continental extension in magmatic rifts: the Turkana Rift case study (North Kenya)
Authors: Vetel William , Le Gall Bernard 
Published: September 2007

Abstract

The Turkana magmatic rift (Northern Kenya) initiated at 45 Ma as one of the nucleation zones of rifting in the East African Rift. It forms an anomalously broad-rifted zone (
c.
200 km) striking with a north-south trend and lying within a NW-SE topographic depression, floored on both sides of the Turkana area by Cretaceous rifts in the Sudan and Anza plains. From a compilation of available data, combined with newly acquired remote sensing and DEM dataset, we propose a five-stage tectono-magmatic model for the Turkana rift evolution (45–23 Ma; 23–15 Ma; 15–6 Ma; 6–2.6 Ma and 2.6 Ma-Present). The corresponding ‘restored’ maps clearly show the changing spatial distribution of magmatism and fault/basin network with time, hence supplying some clues about dynamics of continental extension. First-order basement-rooted transverse faults zones are identified and their influence on nucleation and propagation of strain is demonstrated, whereas the role of magmatic ‘soft-spots’ as concentrating strain is minimized. Blocking of deformation as well as rift jump and lateral transfer of strain are discussed in relation to various types of fault interaction (dip direction, strikes and acute/obtuse angle of the intersecting faults). The causal links between rift nucleation ‘cells’ and inherited transverse weakness zones in the Turkana rift might also exist elsewhere along the eastern branch of the East African Rift, hence suggesting a complex and discontinuous mode of rift propagation.
New constraints on crustal structure in eastern Afar from the analysis of receiver functions and surface wave dispersion in Djibouti
Authors: Dugda Mulugeta T. , Nyblade Andrew A. 
Published: September 2007

Abstract

Crustal structure beneath the GEOSCOPE station ATD in Djibouti has been investigated using
H
-κ stacking of receiver functions and a joint inversion of receiver functions and surface wave group velocities. We obtain consistent results from the two methods. The crust is characterized by a Moho depth of 23 ± 1.5 km, a Poisson’s ratio of 0.31 ± 0.02, and a mean
V
p
of
c.
6.2 km s
−1
but
c.
6.9–7.0 km s
−1
below a 2–5 km-thick low-velocity layer at the surface. Some previous studies of crustal structure for Djibouti placed the Moho at 8 to 10 km depth, and we attribute this difference to how the Moho is defined (an increase of
V
p
to 7.4 km s
−1
in this study vs. 6.9 km s
−1
in previous studies). The crustal structure we obtained for ATD is similar to crustal structure in many other parts of central and eastern Afar. The high Poisson’s ratio and
V
p
throughout most of the crust indicate a mafic composition and are not consistent with models invoking crustal formation by stretching of pre-existing Precambrian crust. Instead, we suggest that the crust in Afar consists predominantly of new igneous rock emplaced during the late syn-rift stage where extension is accommodated within magmatic segments by dyking. Sill formation and underplating probably accompany the dyking to produce the new and largely mafic crust.
Crustal structure of the northern Main Ethiopian Rift from receiver function studies
Authors: Stuart G.W. , Bastow I.D. , Ebinger C.J. 
Published: September 2007

Abstract

The northern Main Ethiopian Rift captures the crustal response to the transition from continental rifting in the East African rift to the south, to incipient seafloor spreading in the Afar depression to the north. The region has also undergone plume-related uplift and flood basalt volcanism. Receiver functions from the EAGLE broadband network have been used to determine crustal thickness and average
V
p
/
V
s
for the northern Main Ethiopian Rift and its flanking plateaus.

On the flanks of the rift, the crust on the Somalian plate to the east is 38 to 40 km thick. On the western plateau, there is thicker crust to the NW (41–43 km) than to the SW (<40 km); the thinning taking place over an off-rift upper mantle low-velocity structure previously imaged by travel-time tomography. The crust is slightly more mafic (
V
p
/
V
s
∼ 1.85) on the western plateau on the Nubian Plate than on the Somalian Plate (
V
p
/
V
s
∼ 1.80). This could either be due to magmatic activity or different pre-rift crustal compositions. The Quaternary Butajira and Bishoftu volcanic chains, on the side of the rift, are characterized by thinned crust and a
V
p
/
V
s
> 2.0, indicative of partial melt within the crust.

Within the rift, the
V
p
/
V
s
ratio increases to greater than 2.0 (Poisson’s ratio, σ > 0.33) northwards towards the Afar depression. Such high values are indicative of partial melt in the crust and corroborate other geophysical evidence for increased magmatic activity as continental rifting evolves to oceanic spreading in Afar. Along the axis of the rift, crustal thickness varies from around 38 km in the south to 30 km in the north, with most of the change in Moho depth occurring just south of the Boset magmatic segment where the rift changes orientation. Segmentation of crustal structure both between the continental and transitional part of the rift and on the western plateau may be controlled by previous structural inheritances. Both the amount of crustal thinning and the mafic composition of the crust as shown by the observed
V
p
/
V
s
ratio suggest that the magma-assisted rifting hypothesis is an appropriate model for this transitional rift.
Coal Desulphurisation and Ash Removal in Intensified Magnetic Fields
Authors: Saeid A. M. , Butcher D. A. , Rowson N. A. 
Published: September 2007

Data is presented demonstrating the effect of high gradient/high
strength magnetic fields on a UK coal. Experimentation was carried out
using a high–intensity (HIW) magnetic separator and coarser coal fractions
were treated on a permanent magnetic roll separator capable of producing
exceptionally high magnetic field gradients.Total sulphur and ash removal data is given for coal fractions after
magnetic treatment plus X–ray diffraction and magnetic profile analysis
provides identification of the mineral constitution of the ash fraction of the
coal.
Bone Morphogenetic Protein 7 in the Development and Treatment of Bone Metastases from Breast Cancer
Authors: Buijs Jeroen T. , Henriquez Nico V. , van Overveld Petra G.M. , van der Horst Geertje , Que Ivo , Schwaninger Ruth , Rentsch Cyrill , ten Dijke Peter , Cleton-Jansen Anne-Marie , Driouch Keltouma , Lidereau Rosette , Bachelier Richard , Vukicevic Slobodan , Clézardin Philippe , Papapoulos Socrates E. , Cecchini Marco G. , Löwik Clemens W.G.M. , van der Pluijm Gabri 
Published: September 2007

Abstract
Bone morphogenetic protein 7 (BMP7) counteracts the physiological epithelial-to-mesenchymal transition (EMT), a process that is indicative of epithelial plasticity. Because EMT is involved in cancer, we investigated whether BMP7 plays a role in breast cancer growth and metastasis. In this study, we show that decreased BMP7 expression in primary breast cancer is significantly associated with the formation of clinically overt bone metastases in patients with ≥10 years of follow-up. In line with these clinical observations, BMP7 expression is inversely related to tumorigenicity and invasive behavior of human breast cancer cell lines. Moreover, BMP7 decreased the expression of vimentin, a mesenchymal marker associated with invasiveness and poor prognosis, in human MDA-MB-231 (MDA-231)-B/Luc+ breast cancer cells under basal and transforming growth factor-β (TGF-β)–stimulated conditions. In addition, exogenous addition of BMP7 to TGF-β–stimulated MDA-231 cells inhibited Smad-mediated TGF-β signaling. Furthermore, in a well-established bone metastasis model using whole-body bioluminescent reporter imaging, stable overexpression of BMP7 in MDA-231 cells inhibited de novo formation and progression of osteolytic bone metastases and, hence, their metastatic capability. In line with these observations, daily i.v. administration of BMP7 (100 μg/kg/d) significantly inhibited orthotopic and intrabone growth of MDA-231-B/Luc+ cells in nude mice. Our data suggest that decreased BMP7 expression during carcinogenesis in the human breast contributes to the acquisition of a bone metastatic phenotype. Because exogenous BMP7 can still counteract the breast cancer growth at the primary site and in bone, BMP7 may represent a novel therapeutic molecule for repression of local and bone metastatic growth of breast cancer. [Cancer Res 2007;67(18):8742–51]
The Nuclear Matrix Protein, NRP/B, Enhances Nrf2-Mediated Oxidative Stress Responses in Breast Cancer Cells
Authors: Seng Seyha , Avraham Hava Karsenty , Jiang Shuxian , Yang Suping , Sekine Masayuki , Kimelman Noam , Li Huchun , Avraham Shalom 
Published: September 2007

Abstract
The transcription factor NF-E2–related factor 2 (Nrf2) translocates into the nucleus and activates phase II genes encoding detoxification enzymes and antioxidant proteins, resulting in the protection of cells from oxidative insults. However, the involvement of Nrf2-mediated oxidative stress responses in breast cancer cells is largely unknown. Notably, during our study of the Nrf2 pathway in breast cancer cells, we observed that the nuclear matrix protein NRP/B was expressed and colocalized with Nrf2 in these cells, suggesting that NRP/B is involved in Nrf2-mediated oxidative stress responses. The expression level of NRP/B was variable in different breast cancer cells and breast cancer tissues, and was found to be localized in the nucleus. NRP/B expression was increased after exposure to the oxidative stress agent, hydrogen peroxide (H2O2), particularly in the highly aggressive MDA-MB-231 breast cancer cells. Association of NRP/B with Nrf2 in vitro and in vivo was observed in MDA-MB-231 breast cancer cells, and this association was up-regulated upon exposure to H2O2, but not to sodium nitroprusside, SIN-1, and DETA-NO. NRP/B also enhanced Nrf2-mediated NAD(P)H:quinine oxidoreductase 1 promoter activity. Thus, this study reveals that NRP/B enhances oxidative stress responses in breast cancer cells via the Nrf2 pathway, identifying a novel role of nuclear matrix protein(s) in oxidative stress responses. [Cancer Res 2007;67(18):8596–604]