bluuebunny/crossref_metadata_2025 huggingface dataset:
Reservoir Modeling for Flow Simulation Using Surfaces, Adaptive Unstructured Meshes and Control-Volume-Finite-Element Methods
Authors: Jackson M. D. , Gomes J. L. , Mostaghimi P. , Percival J. R. , Tollit B. S. , Pavlidis D. , Pain C. C. , El-Sheikh A. H. , Muggeridge A. H. , Blunt M. J.
Published: February 2013

We present new approaches to reservoir modeling and flow simulation that dispose of the pillar-grid concept that has persisted since reservoir simulation began. This results in significant improvements to the representation of multi-scale geological heterogeneity and the prediction of flow through that heterogeneity. The research builds on 20+ years of development of innovative numerical methods in geophysical fluid mechanics, refined and modified to deal with the unique challenges associated with reservoir simulation.

Geological heterogeneities, whether structural, stratigraphic, sedimentologic or diagenetic in origin, are represented as discrete volumes bounded by surfaces, without reference to a pre-defined grid. Petrophysical properties are uniform within the geologically-defined rock volumes, rather than within grid-cells. The resulting model is discretized for flow simulation using an unstructured, tetrahedral mesh that honors the architecture of the surfaces. This approach allows heterogeneity over multiple length-scales to be explicitly captured using fewer cells than conventional corner-point or unstructured grids.

Multiphase flow is simulated using a novel mixed finite element formulation centered on a new family of tetrahedral element types, PN(DG)-PN+1, which has a discontinuous Nth-order polynomial representation for velocity and a continuous (order N+1) representation for pressure. This method exactly represents Darcy force balances on unstructured meshes and thus accurately calculates pressure, velocity and saturation fields throughout the domain. Computational costs are reduced through (i) automatic mesh adaptivity in time and space and (ii) efficient parallelization. Within each rock volume, the mesh coarsens and refines to capture key flow processes, whilst preserving the surface-based representation of geological heterogeneity. Computational effort is thus focused on regions of the model where it is most required.

Having validated the approach against a set of benchmark problems, we demonstrate its capabilities using a number of test models which capture aspects of geological heterogeneity that are difficult or impossible to simulate conventionally, without introducing unacceptably large numbers of cells or highly non-orthogonal grids with associated numerical errors. Our approach preserves key flow features associated with realistic geological features that are typically lost. The approach may also be used to capture near wellbore flow features such as coning, changes in surface geometry across multiple stochastic realizations and, in future applications, geomechanical models with fracture propagation, opening and closing.
A Soft and Law-Abiding Framework for History Matching and Optimization under Uncertainty
Authors: Hajizadeh Yasin , Nghiem Long , Mirzabozorg Arash , Yang Chaodong , Li Heng , Costa Sousa Mario
Published: February 2013

Current frameworks for optimization and assisted history matching lack the ability to control and guide the sampling engine and to incorporate geo-engineering knowledge. Defining the interactions between uncertain parameters and handling multiple constraints are also arduous tasks. Despite recent advances in adaptive population-based sampling algorithms and other gradient and ensemble-based methods, these specific drawbacks have left engineers with several history-matched models that are inconsistent with the physical and geological knowledge of the field.

We introduce a novel rule-based framework based on fuzzy reasoning to integrate engineering knowledge with optimization and assisted history matching workflows. The system can handle multiple complex constraints both in parameter and objective function space. The use of fuzzy set theory in this workflow is a natural way to address uncertainty arising from imprecision of definition. This type of uncertainty is important in expressing the parameters of interest; however, it has been less addressed in existing workflows. The proposed system can be coupled with any algorithm used for assisted history matching, including gradient-based, population-based and particle filter approaches.

The framework is coupled with differential evolution algorithm and is tested for three cases. The results show that fuzzy rule-based engine preserves the computational efficiency of the sampling engine, while allowing for definition of flexible rules in history matching and optimization that honor engineering knowledge.
A Novel Approach for Incorporation of Capillarity and Gravity Into Streamline Simulation Using Orthogonal Projection
Authors: Tanaka Shusei , Datta-Gupta Akhil , King Michael J.
Published: February 2013

The effective use of streamline simulators for flow simulation of multi-million cell detailed 3D models relies on the ability to take large simulation time-steps with few pressure solutions. For processes that are convective, the streamline approach works quite well while for flow simulation with compressibility, strong capillarity or strong gravity terms, the maximum time step size may be substantially reduced, limiting the utility of streamline simulation. This is the case when applying the conventional streamline operator-splitting approach, where the nonlinear terms associated with capillarity and gravity limit the time step. Earlier studies have shown the importance of an "anti-diffusive" correction in which numerical dispersion from the convective solution must be removed before capillary pressure can be accurately modeled. Evaluation of the anti-diffusive term involves the solution of a local Riemann problem which, unfortunately, is difficult to determine in full field multi-dimensional problems with heterogeneity, and spatially variable viscosity, fluid velocity, and saturations. The alternative approach is to perform the operating splitting calculation with very small time-steps to minimize the numerical dispersion, but this is not an effective simulation strategy.

In our approach, the equations are reformulated so that all of the flux terms including capillarity and gravity forces are solved simultaneously with the streamline convection equations. We utilize an orthogonal projection method in which the fluxes of capillary and gravity are separated into components parallel and orthogonal to the total velocity. Fluxes parallel to total velocity are included within the solution of the convective flow equations on streamlines. The remaining terms are calculated on the underlying three dimensional grid. With the introduction of this orthogonal-projection, there is no longer a need for an anti-diffusive correction. This formulation still uses an operator splitting approach, but the size of the remaining transverse flux correction terms are reduced, allowing for large time steps.

We demonstrate the utility and validity of our approach using a series of increasingly complex numerical experiments in 1D and 2D including the 3D SPE10 reservoir model. We compare our results to a commercial finite difference simulator, and to a streamline simulator using a conventional operator splitting approach, but without the anti-diffusive correction. We obtain a good match to the saturation distribution and production profile using large time steps, compared to the small time steps required for conventional operator splitting. The 2D and 3D examples clearly demonstrate the effectiveness of the orthogonal projection approach in minimizing the transverse flux allowing for the larger time steps. It also provides a systematic means of including additional displacement mechanisms in the future.
Developement of Algebraic Multigrid Solvers Using GPUs
Authors: Liu Hui , Yu Song , Chen Zhangxin
Published: February 2013

In reservoir simulation, algebraic multigrid (AMG) solvers are the most effective solvers for linear systems arising from the discretization of pressure equations. The AMG solvers are also important components for many multi-stage preconditioners. In this paper, we introduce our work on developing these solvers on NVIDIA Tesla GPUs. A classical algebraic multigrid solver is developed. Numerical experiments are performed to test the efficiency of this GPU-based parallel AMG solver. The numerical experiments show that the GPU-based algebraic solver is sped up to 12.5 times faster than the corresponding CPU-based algebraic multigrid solver.
Techniques for Effective Simulation, Optimization, and Uncertainty Quantification of the In-situ Upgrading Process
Authors: Alpak Faruk O. , Vink Jeroen C. , Gao Guohua , Mo Weijian
Published: February 2013

Strongly temperature-dependent compositional flow and transport, chemical reactions, delivery of energy into the subsurface through downhole heaters, and complex natural fracture architecture render the dynamic modeling of In-situ Upgrading Process (IUP) a computationally challenging endeavor for carbonate extra-heavy oil resources. Economic performance indicators for such recovery methods can be considerably enhanced via simulation or simulation-based proxy models within an optimization framework (e.g., maximizing Net Present Value through achieving an optimal compromise between hydrocarbon recovery and the number of heater wells). The IUP is endowed with uncertain subsurface parameters as in the case of other recovery mechanisms. The number of subsurface uncertainties is especially large and the impacts of these uncertainties are intricate when IUP is applied to a complex naturally-fractured carbonate reservoir. Simulation results must reflect the impacts of these uncertainties; hence they should always deliver "expected-value production functions" and their attached uncertainty ranges, in short, the "error bars". Both the optimization and the uncertainty quantification workflows require (typically multiple) multi-scenario simulations, and are therefore very compute intensive.

We describe our recent developments in simulation techniques, optimization algorithms, tool capabilities, and high-performance computing protocols that in unison form a massively parallel simulation/optimization/uncertainty-quantification workflow, in which it is almost equally easy to produce recovery time-functions with an attached uncertainty range, as it is to run a single simulation. Uncertainties are integral part of the simulation models in our dynamic modeling workflow. Our in-house simulation platform supports various optimization and uncertainty quantification methods, such as conventional as well as robust optimization using a novel Simultaneous Perturbation and Multivariate Interpolation technique, Experimental Design, and Monte Carlo simulation, that can be linked together through a unified script-based interface, to carry out optimization in the presence of subsurface uncertainties and to quantify the impact of these uncertainties on simulation results. Application of our massively parallel dynamic modeling workflow is illustrated on a proprietary IUP recovery method for a complex naturally fractured extra-heavy oil (bitumen) reservoir as example. After briefly explaining these recovery processes and the modeling approach, we show the techniques (including their accompanying application results) that (1) notably accelerate the (single-model) simulation process, (2) effectively identify the predominant subsurface uncertainties, (3) rapidly optimize heater-producer patterns under the influence of predominant subsurface uncertainties, and (4) efficiently compute expected-value production functions with error bars.
Tie-Simplex-Based Phase Behavior Modeling in an IMPEC Reservoir Simulator
Authors: Rezaveisi M. , Sepehrnoori K. , Johns R. T.
Published: February 2013

Numerical simulation of gas injection processes requires coupling of phase equilibrium equations with complex multiphase flow equations. Standard EOS-based phase equilibrium modeling in reservoir simulators involves computationally intensive and time-consuming calculations for stability analysis and flash calculations. Therefore, speeding up stability analysis and flash calculations is an active research area.

Recently, the tie-simplex based phase behavior modeling in reservoir simulators has been applied and investigated as a potential method for improving the computational speed of EOS-based reservoir simulators. The most promising of the tie-simplex based approaches in terms of practicality and computational efficiency is Compositional Space Adaptive Tabulation (CSAT). We implemented CSAT in UTCOMP, The University of Texas’s in-house IMPEC compositional reservoir simulator to investigate its computational efficiency compared to the phase behavior algorithm in the original UTCOMP. Several example miscible and immiscible case studies are presented.

The results show that using CSAT to generate initial estimates for flash calculations is inefficient compared to the original UTCOMP's phase behavior algorithm. Applying CSAT to only skip stability analysis does improve the computational time, but only when a significant portion of the grid blocks are in the single-phase region and no other technique for avoiding stability analysis is used. CSAT may skip as much as 99% of the stability analyses performed in the base case original UTCOMP, which may amount to about 30% improvement in total computational time in such cases. However, in most cases there is little or no computational advantage to use CSAT when the simple option in UTCOMP is used where stability analysis is skipped for blocks surrounded by single-phase regions. Thus, we see no reason to implement CSAT into an IMPEC type simulator over other simpler schemes to avoid stability analyses. We explore in detail the performance of CSAT, which depends significantly on the specific gas flood modeled, and the number of tie lines generated during adaptive tabulation. The number of tie lines generated depends on tolerances specified for tie-line detection and for acceptance of a phase stability skip.

The results shed light on applicability of CSAT in the IMPEC type compositional reservoir simulators and show that the advantages of CSAT are not as great as initially thought.
Load-based approaches for modelling visual clarity in streams at regional scale
Authors: Elliott A. H. , Davies-Colley R. J. , Parshotam A. , Ballantine D.
Published: February 2013

Reduction of visual clarity in streams by diffuse sources of fine sediment is a cause of water quality impairment in New Zealand and internationally. In this paper we introduce the concept of a load of optical cross section (LOCS), which can be used for load-based management of light-attenuating substances and for water quality models that are based on mass accounting. In this approach, the beam attenuation coefficient (units of m–1) is estimated from the inverse of the visual clarity (units of m) measured with a black disc. This beam attenuation coefficient can also be considered as an optical cross section (OCS) per volume of water, analogous to a concentration. The instantaneous ‘flux’ of cross section is obtained from the attenuation coefficient multiplied by the water discharge, and this can be accumulated over time to give an accumulated ‘load’ of cross section (LOCS). Moreover, OCS is a conservative quantity, in the sense that the OCS of two combined water volumes is the sum of the OCS of the individual water volumes (barring effects such as coagulation, settling, or sorption). The LOCS can be calculated for a water quality station using rating curve methods applied to measured time series of visual clarity and flow. This approach was applied to the sites in New Zealand's National Rivers Water Quality Network (NRWQN). Although the attenuation coefficient follows roughly a power relation with flow at some sites, more flexible loess rating curves are required at other sites. The hybrid mechanistic–statistical catchment model SPARROW (SPAtially Referenced Regressions On Watershed attributes), which is based on a mass balance for mean annual load, was then applied to the NRWQN dataset. Preliminary results from this model are presented, highlighting the importance of factors related to erosion, such as rainfall, slope, hardness of catchment rock types, and the influence of pastoral development on the load of optical cross section.
Remote sensing models using Landsat satellite data to monitor algal blooms in Lake Champlain
Authors: Trescott A. , Park M.-H.
Published: February 2013

Lake Champlain is significantly impaired by excess phosphorus loading, requiring frequent lake-wide monitoring for eutrophic conditions and algal blooms. Satellite remote sensing provides regular, synoptic coverage of algal production over large areas with better spatial and temporal resolution compared with in situ monitoring. This study developed two algal production models using Landsat Enhanced Thematic Mapper Plus (ETM+) satellite imagery: a single band model and a band ratio model. The models predicted chlorophyll a concentrations to estimate algal cell densities throughout Lake Champlain. Each model was calibrated with in situ data compiled from summer 2006 (July 24 to September 10), and then validated with data for individual days in August 2007 and 2008. Validation results for the final single band and band ratio models produced Nash–Sutcliffe efficiency (NSE) coefficients of 0.65 and 0.66, respectively, confirming satisfactory model performance for both models. Because these models have been validated over multiple days and years, they can be applied for continuous monitoring of the lake.
A methodological strategy to analyze and improve the French rainwater harvesting regulation in relation to quality
Authors: de Gouvello B. , Nguyen-Deroche N. , Lucas F. , Gromaire M.-C.
Published: February 2013

In 2008, France implemented a regulation framework for rainwater harvesting (RWH). This framework implicitly defines several categories of rainwater quality for different uses through specific technical requirements to be implemented. This paper presents a detailed analysis of these requirements. Then, results concerning the bacteriological and physicochemical water quality from past on-site studies undertaken in France are compared in order to develop a methodological strategy aiming to validate, clarify or invalidate them through future experiments.
Grassland communities of Stol mountain (eastern Serbia ): Vegetation and environment al relationships
Authors: Acic Svetlana , Silc U. , Vrbnicanin S. , Cupac Svjetlana , Topisirovic G. , Stavretovic N. , Dajic-Stevanovic Zora
Published: February 2013

The systematic survey of grassland communities was performed on Mt. Stol
(eastern Serbia). The main aims of the research were to: (1) determine
grassland vegetation types of the researched area; (2) correlate the impacts
of the soil and environmental conditions on the occurrence of certain plant
communities, and (3) comment on the conservational value of the grasslands in
the researched area. The data set included 60 phytosociological relev?s of
grasslands recorded between 2001 and 2004. The main environmental gradients
of species composition were analyzed by Detrended Correspondence Analysis
(DCA). For the ecological interpretation of ordination axes, ecological
indicator values were used. Three associations were distinguished:
Danthonietum calycinae, Asperulo-Agrostietum vulgaris and Ranunculo bulbosi-
Arrhenatheretum elatioris belonging to two alliances and two classes:
Chrysopogono-Danthonion - Festuco-Brometea and Arrhenatherion -
Molinio-Arrhenatheretea. The results of the DCA support our assumption that
the main environmental gradient in the species composition of the grasslands
is related to nutrients and moisture. The conservational value of grasslands
in the researched area is discussed.
A new cave species of the genus Hyleoglomeris Verhoeff, 1910, from the Balkan Peninsula (Diplopoda: Glomerida: Glomeridae)
Authors: Makarov S.E. , Curcic B.P.M. , Antic D.Z. , Tomic V.T. , Curcic S.B. , Ilic B. , Lucic L.R.
Published: February 2013

A new troglobitic diplopod, Hyleoglomeris faberi n. sp., is described from a
cave in western Serbia. Taxonomic relationships among European members of the
genus Hyleoglomeris Verhoeff, 1910 (and some related taxa) and a number of
biogeographical data are briefly discussed.
Biological activity of Aronia melanocarpa antioxidants pre-screening in intervention study design
Authors: Konic-Ristic Aleksandra , Srdic-Rajic Tatjana , Kardum Nevena , Glibetic Marija
Published: February 2013

Beneficial effects of black chokeberry fruits and juices in health promotion
and prevention of chronic diseases shown both in epidemiological and dietary
intervention studies are often connected with their antioxidant activity. The
aim of this study was to investigate the total phenolics and anthocyanins
content, chemical antioxidant activity (DPPH-assay), antioxidant protection
in erythrocytes and anti-platelet activity in vitro of three different
chokeberry products: commercial and fresh pure chokeberry juice and crude
lyophilized water-ethanol extract of chokeberry fruits, as a part of their
pre-clinical evaluation. Obtained results indicated the differences in
chemical composition and antioxidant activity of investigated products.
Cellular effects, including both in vitro anti-platelet and antioxidant
effects, were not directly correlated with the chemical antioxidant activity
and results obtained in vitro for anti-platelet effects just partially
consistent with the results obtained in vivo, in a pilot intervention trial.
In conclusion, chemical analyses and in vitro experiments on foods and their
bioactives are a valuable pre-screening tool for the evaluation of their
biological activity. However, extrapolation of the obtained results to the in
vivo settings is often limited and influenced by the bioavailability and
metabolism of native dietary compounds or interactions with different
molecules within the human body.
Palladium(II) complexes with R2edda derived ligands: Part VI. O,O’-diisopropyl-(S,S)-ethylenediamine-N,N’-di-2-(4-methyl)pentanoate dihydrochloride dihydrate and its palladium(II) complex: Synthesis and characterization
Authors: Zmejkovski Bojana , Sabo Tibor , Kaludjerovic Goran
Published: February 2013

A new R2edda-type ester, O,O?-diisopropyl-(S,S)-ethylenediamine-N,N?-di-2-(4-methyl)-pentanoate
dihydrochloride dihydrate, [(S,S)-H2iPr2eddl]Cl2?2H2O, 1, and its palladium(II) complex,
dichlorido(O,O?-diisopropyl-(S,S)-ethylenediamine-N,N?-di-2-(4-methyl)pentanoate)palla-dium(II)
hemihydrate, [PdCl2{(S,S)-iPr2eddl}]?0.5H2O, 2, were synthesized and characterized by elemental analysis,
IR and NMR spectroscopy. As expected the palladium(II) complex is found in two from three
diastereoisomeric forms (R,R), (S,S) and (R,S)?(S,R).
Evaluation of disease frequency in the first line relatives of patients suffering from schizophrenia related to gender and diagnostic categories
Authors: Sulejmanpasic-Arslanagic Gorana
Published: February 2013

Introduction. Schizophrenia represents the most severe mental disorder. The
aim of this study was to determine the frequency of disease in the first line
relatives of patients suffering from schizophrenia related to gender
differences and various subtypes. Material and Methods. The study included
453 subjects (121 patients suffering from schizophrenia - 52.1% males and
47.9% females and 332 first line relatives of the patients - 47.2% males and
52.7% females during a five year period, mostly in the region of Sarajevo.
Results. According to the analysis of disease frequency related to the
kinship, the disease developed more frequently in mothers (8.3%) and sisters
(7.8%) than in fathers (6.9) and brothers (7.1%) of the patients suffering
from paranoid schizophrenia. In the group of disorganized schizophrenia, only
mothers were found (4.2%), whereas the statistical difference in the group of
affected brothers and sisters was significant, the percentage being 9.7% and
15.3%, respectively. There was a statistically significant difference in
gender (p<0.05) between the group of parents and siblings regarding the
frequency of schizophrenia. Discussion. The proof of participation of genetic
factors in etiology supports the assumption on genetic nature of familial
aggregation of schizophrenia. Our results completely match those of studies
which analyzed the frequency of disease regarding inheritance (gender
distribution and various subtypes). Conclusion. Investigation points to the
common epidemiological criteria regarding the frequency of schizophrenic
psychosis. Genetic predisposition could be also a demonstrator of the disease
course and outcome, which should enable better understanding of the etiology
of this disease.
The Role of Analysts in Intra-Industry Information Transfer
Authors: Hilary Gilles , Shen Rui
Published: February 2013

When a firm issues a management forecast, analysts who have observed more forecasts from this firm since covering it (i.e., have more MF-Experience) subsequently improve their own accuracy more and provide timelier earnings forecasts for other (non-issuing) firms in the same industry. We also find that, subsequent to a management forecast, investors are more responsive to forecast revisions for non-issuing firms made by analysts with more MF-Experience. Further tests suggest that our results are not explained by endogeneity in firm coverage.

Data Availability: Data are commercially available.
Conservative Treatment of Complicated Oblique Crown-root Fractures of Molars: A Report of Five Representative Cases
Authors: Wang P , He W , Ni L , Lu Q , Sun H
Published: February 2013

The five cases presented here describe a conservative treatment procedure for complicated crown-root fractures of molars with extensive loss of tooth structure. After the mobile crown-root fragments were extracted, the remaining crowns were restored at the juxtagingival level. The follow-up time ranged from two years, seven months, to four years. At the follow-up examinations, all of the teeth were asymptomatic and had healthy clinical appearances. There was no evidence of pockets related to fractures. The results of these cases show that complete periodontal healing is possible with conservative treatment of complicated crown-root fracture of molars.
Control of T-2 Toxin in Fusarium Langsethiae and Geotrichum Candidum Co-Culture / Kontrola Toksina T-2 U Kokulturi Fusarium Langsethiae I Geotrichum Candidum
Authors: Gastélum-Martínez Elida , Compant Stephane , Taillandier Patricia , Mathieu Florence
Published: February 2013

Due to contamination of barley grains by Fusarium langsethiae, T-2 toxin can be present in the brewing process. It has been observed that the presence of the yeast Geotrichum candidum during malting can reduce the final concentration of this mycotoxin in beer. In this work, a co-culture method was carried out for both microorganisms in order to evaluate the effect on T-2 mycotoxin concentration in comparison with the pure culture of F. langsethiae in the same conditions. The microbial growth of both microorganisms was assessed using three different methods: dry weight, DOPE-FISH, and DNA quantification. In coculture, both microorganisms globally developed less than in pure cultures but G. candidum showed a better growth than F. langsethiae. The concentration of T-2 was reduced by 93 % compared to the pure culture. Hence, the interaction between G. candidum and F. langsethiae led to a drastic mycotoxin reduction despite the only partial inhibition of fungal growth
Provenance of Paleozoic very low- to low-grade metasedimentary rocks of South Tisia (Slavonian Mountains, Radlovac Complex, Croatia)
Authors: Biševac Vanja , Krenn Erwin , Finger Fritz , Lužar-Oberiter Borna , Balen Dražen
Published: February 2013

Monazite age dating, detrital heavy mineral content and whole-rock geochemistry provided insight into the provenance, depositional history and paleogeological setting of the Radlovac Complex very low- to low-grade metasedimentary rocks (South Tisia, Slavonian Mountains, Croatia). Electron microprobe based Th-U-Pb dating of detrital monazite indicates a Variscan age of the protolith (330 ± 10 Ma). The detrital heavy mineral assemblages of representative metasedimentary rocks are dominated by apatite, zircon, tourmaline and rutile accompanied by minor quantity of epidote/zoisite, monazite and titanite. Judging from the heavy mineral assemblage, felsic igneous rocks served as the source material. This is consistent with the major and trace element spectrum of studied metasedimentary rocks characterized by high concentration of Th, high L + MREEs and high ratios of La/Sc, Th/Sc, La/Co, Th/Co and Th/Cr. The occurrence of magmatic monazite, zircon and xenotime and the absence of metamorphic heavy minerals suggest that granitoids, migmatites and migmatitic gneisses served as one major source for the metapsammites. Such rock types are commonly exposed in the Papuk Complex of the older surrounding complexes, while the Psunj Complex also contains metamorphic rocks. This is in good correlation with the monazite ages presented here which fits better with ages of Papuk Complex representative rocks than with those of the Psunj Complex known from the literature. Overall, data show that the Radlovac Complex represents the detritus of the local Variscan crust characterized by granitoid bodies, migmatites and migmatitic gneisses typical for the Papuk Complex.
Composition and alteration of Cr-spinels from Milia and Pefki serpentinized mantle peridotites (Pindos Ophiolite Complex, Greece)
Authors: Kapsiotis Argyrios
Published: February 2013

The Pindos Ophiolite rocks include variably serpentinized peridotites derived from a harzburgitic and subordinately dunitic mantle. In the serpentinized matrix of these rocks pseudomorphic (mesh, bastite) and non-pseudomorphic (interpenetrating, type-2 hourglass) textures were recognized. Chromian spinel (Cr-spinel) is anhedral to subhedral and often replaced by a porous opaque phase. Chemistry data show that Cr-spinel cores retain their original composition, having Cr#[Cr/(Cr + Al)] that ranges between 0.45 and 0.73, and Mg#[Mg/(Mg + Fe2+)] that varies between 0.52 and 0.65, accompanied by low content in TiO2 ( < 0.11wt. %). The relatively wide variation of their Cr# values reflects that the studied peridotites were produced by variable degrees of melting. It is likely that the Pindos peridotites represent mantle residues originally formed in a mid-ocean ridge (MOR) environment, which were subsequently entrapped as part of a mantle wedge above a supra-subduction zone (SSZ) regime. Cr-spinel adjacent to clinochlore systematically displays limited compositional and textural zoning along grain boundaries and fractures. However, the degree of peridotite serpentinization does not correlate with the abundance of zoning effects in accessory Cr-spinel. Thus, Cr-spinel zoning is thought to represent a secondary feature obtained during the metamorphic evolution of the host peridotites. Core to rim compositional trends are expressed by MgO and Al2O3 impoverishment, mainly compensated by Cr2O3 and FeO increases. Such chemical trends are produced as a result of Cr-spinel re-equilibration with the surrounding serpentine, and their subsequent replacement by ferrian (Fe3+-rich) chromite and clinochlore, respectively, during a brief, fluid assisted, greenschist facies metamorphism episode (T > 300 °C). The limited occurrence of ferrian chromite with high Fe3+# values suggests that elevated oxidizing conditions were prevalent only on a local scale during Cr-spinel alteration
Central low-grade osteosarcoma with an unusual localization in the diaphysis of a 12-year old patient
Authors: Gilg Magdalena Maria , Liegl Bernadette , Wibmer Christine , Maurer-Ertl Werner , Leithner Andreas
Published: February 2013

Background. Low-grade central osteosarcoma is a very rare subtype of osteosarcoma with a predilection for the metaphysis of long bones and a peak incidence in the 3rd decade of life. Absence of specific clinical symptoms and a good prognosis after wide resection are the characteristics of this entity. Chemotherapy is not indicated in this highly differentiated tumour.

Case report. A 12-year old girl presented with limping, swelling and pain in the mid of the left femur. Radiography showed a 12 cm long intraosseous expansion with lamellated periosteal reaction and contrast medium enhancement in MRI. Although radiology led to the differential diagnoses of Ewing’s sarcoma, osteomyelitis and fibrous dysplasia, the histological specimen showed a hyopocellular spindle-cell proliferation arranged in fascicles with mild cytologic atypia and only single mitotic figures. In synopsis with radiology the diagnosis of low-grade central osteosarcoma was made and confirmed by reference pathology. The tumour was resected with wide margins and reconstruction was performed with a vascularized fibula, a homologous allograft and a plate. Staging was negative for recurrence and metastasis at a follow-up of 16 months.

Conclusions. Low-grade osteosarcoma accounts for only 1% of all osteosarcomas with a peak incidence in the 3rd decade. The diaphyseal localization and the young age make this case special. To achieve the correct diagnosis of this rare low-grade entity and thereby the adequate treatment, despite a wide range of differential diagnoses, a multidisciplinary approach is essential.
Preparation of aluminium ammonium calcium phosphates using microwave radiation
Authors: Łuczka Kinga , Sibera Daniel , Smorowska Aleksandra , Grzmil Barbara
Published: February 2013

Microwave radiation was used in the acquisition of aluminium ammonium calcium phosphates. The substrates such as CaCO3, H3PO4, aqueous ammonia were reagent grade, whereas Al(OH)3 was prepared afresh. The influence of process parameters (pH 6 ± 2, molar ratios of Al3+: Ca2+: PO43− in the substrates, respectively 0.31: 0.62: 1; 0.5: 0.5: 1; 0.72: 0.36: 1) on the phase composition and the product properties was determined. Statistical software STATISTICA 10 was used for planning and evaluation of the experiments. The process parameters making it possible to acquire the material with the anticipated physicochemical properties were determined based on statistical evaluation of the planned research by the plan fractional factorial design at three levels 3(k−p). The phase composition of the samples was studied using XRD analysis. The specific surface area was calculated using the BET method and the particle size was determined by LSM. Materials with a molar ratio of Al3+: Ca2+ and Al3+: NH4+ in the range of 0.07–0.76 and 0.75–3.4, respectively, with an absorption oil number of 36–56 g per 100 g, S BET within 8.2–73 m2 g−1, and particle size in the range of 156–252 nm were obtained.
Influence of ethanol on the chain-ordering of carbonised polyaniline
Authors: Morávková Zuzana , Trchová Miroslava , Tomšík Elena , Stejskal Jaroslav
Published: February 2013

Polyaniline (PANI) was prepared by the oxidation of aniline hydrochloride with ammonium peroxydisulphate in water or in a water-ethanol mixture. In the presence of ethanol, PANI nanotubes and nanorods were observed. Both products were carbonised in a nitrogen atmosphere at 650°C. Initial and carbonised products were characterised by scanning and transmission electron microscopies, thermogravimetric analysis and wide-angle X-ray scattering. Their molecular structure was studied by UV-VIS, infrared, and Raman spectroscopies. Carbonised sample obtained from the PANI salt prepared in the presence of ethanol exhibits Raman spectrum which corresponds to a more ordered carbon-like material than carbonised samples obtained from the PANI base and the PANI salt prepared in pure water. The influence of ethanol present in the reaction mixture on the molecular and supra-molecular structure of PANI and, consequently, on the enhancement of chainordering of carbonised PANI is discussed.
Enzymatic synthesis of kojic acid esters and their potential industrial applications
Authors: Lajis Ahmad , Basri Mahiran , Mohamad Rosfarizan , Hamid Muhajir , Ashari Siti , Ishak Nurazwa , Zookiflie Azulia , Ariff Arbakariya
Published: February 2013

In this paper, enzymatic methods for the synthesis of 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one (kojic acid) esters are reviewed. Important process parameters related to the synthesis of kojic acid esters such as the type of immobilized lipase, solvent, temperature, initial water activity, water content, pH, metal salts, enzyme loading, substrates mole ratio, and acyl donors are highlighted and discussed. The properties of kojic acid esters related to their solubility, stability, cytotoxicity, depigmenting activity, tyrosinase inhibitory, metal-chelating, anti-oxidant, and other biological activities are also highlighted. At present, kojic acid and its esters are widely used in cosmetic and skin health industries as skin whitening agents. The advantages and disadvantages of various kojic acid esters are compared and possible industrial applications of these derivatives are also discussed.
Synthesis and spectroscopic characterisation of (E)-2-(2-(9-(4-(1H-1,2,4-triazol-1-yl)butyl)-9H-carbazol-3-yl)vinyl)-3-ethylbenzo[d]thiazol-3-ium, a new ligand and potential DNA intercalator
Authors: Głuszyńska Agata , Rajczak Ewa , Juskowiak Bernard
Published: February 2013

Three new compounds based on carbazole planar skeleton were synthesised. Among them there is a new ligand and a potential DNA intercalator which contains a benzothiazolium moiety connected to the carbazole ring by a vinyl bridge. The absorption and emission spectral properties of this new ligand have been studied by spectroscopic methods.
Selective oxidation of metallic single-walled carbon nanotubes
Authors: Łukaszczuk Paweł , Mijowska Ewa , Kaleńczuk Ryszard
Published: February 2013

In this work we present a simple and non-invasive approach to the preparation of semi-conducting single-walled carbon nanotubes (SWCNTs) through selective destruction of the metallic counterparts present in the starting material. Most separation techniques require chemical treatment, the application of ultrasound, or the addition of auxiliary molecules, which lead to the introduction of defects and impurities. In this contribution, laser ablation SWCNTs were selectively oxidised via long-term heating leading to the enrichment of semi-conductive nanotubes. Spectroscopic analysis demonstrates that the selective character of oxidation occurs only in the optimal temperature range, determined by thermo-gravimetric analysis. By tuning the process parameters, one can obtain a sample exhibiting different purity (up to 95 % of semi-conducting nanotubes) and separation efficiency. The samples’ quality and yield of separation were determined by UV-VIS-NIR spectroscopy, Raman spectroscopy, and TG analysis. The approach presented is readily scaleable.
Evaluation of waste products in the synthesis of surfactants by yeasts
Authors: Dzięgielewska Ewelina , Adamczak Marek
Published: February 2013

The highest yields of biosurfactants were obtained by: (i) Pseudozyma antarctica (107.2 g L−1) cultivated in a medium containing post-refining waste; (ii) Pseudozyma aphidis (77.7 g L−1); and (iii) Starmerella bombicola (93.8 g L−1) both cultivated in a medium with soapstock; (iv)Pichia jadinii (67.3 g L−1) cultivated in a medium supplemented with waste frying oil. It was found that the biosurfactant synthesis yield increased in all strains when the cell surface hydrophobicity reached 70–80 %, enabling the microbial cells to make good contact with hydrophobic substrates. The lowest surface tension of the post-cultivation medium was from 32.0 mN m−1 to 37.8 mN m−1. However, this parameter (which was also determined by a drop collapse assay) was of limited use in monitoring biosurfactant synthesis in this study. The crude glycerol was not a good substrate for biosurfactant synthesis although, in the case of P. aphidis, 67.4 g L−1 of biosurfactants were obtained after cultivation in the medium supplemented with glycerol fraction (GF2). In a low-cost medium containing soapstock and whey permeate or molasses, about 90 g L−1 of mannosylerythritol lipids were synthesised by P. aphidis and approximately 40 g L−1 by P. antarctica.
Biochemical characteristics of myofibrillar proteins of the fish parasite Isoparorchis hypselobagri (Trematoda) as survival traits in an oxygen-rich environment
Authors: Abbasi Usma , Ahmad Riaz , Hasnain Absar-ul
Published: February 2013

We have investigated biochemical properties of myofibrillar proteins of the digenetic trematode Isoparorchis hypselobagri, which correlate with its survival in the oxygen-rich swim bladder of its host catfish (Wallago attu). The polypeptide composition of the trematode’s natural actomyosin (NAM) was striated-muscle-like, with the exception that a 98-kD polypeptide corresponding to paramyosin also existed in its sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) profiles. The profiles of immunoprecipitated NAM of the trematode support these inferences. Ca2+-sensitivity of myofibrillar contractility and Mg2+-ATPase activity of I. hypselobagri resembled troponin-linked calcium regulation of the host striated muscle. Myofibrillar permeability to water influx was insensitive to calcium chelation at neutral pH. However, the host swim bladder myofibrils displayed smooth-muscle-like polypeptide composition, pH dependence of contractility, Ca2+-sensitivity, ATPase activities, and inactivation kinetics. We propose 2 survival strategies that I. hypselobagri appears to have co-evolved: (i) fast-muscle-like musculature with exceptionally high contractility or ATPase activity; and (ii) type-II myosin resembling the host muscle in functional plasticity.
Occurrence of the nan1 gene and adhesion of Pseudomonas aeruginosa isolates to human buccal epithelial cells
Authors: Wolska Katarzyna , Kot Barbara , Mioduszewska Halina , Sempruch Cezary , Borkowska Lidia , Rymuza Katarzyna
Published: February 2013

This study shows an association between the frequency of the nan1 gene (encoding neuraminidase) among 62 clinical Pseudomonas aeruginosa isolates and adhesion of these bacteria to human buccal epithelial cells. The 52 strains in which the gene was present (83.9%) were characterized by a higher adhesiveness (the mean number of adhering bacteria was 23.51 per cell) than strains in which the gene was not detected (16.23 per cell) and the difference was significant (P = 0.009, Mann-Whitney U test). Thus we found that the nan1 gene may play a role in the binding of clinical P. aeruginosa strains to buccal cells.
What is the impact of the participation of Czech SMEs in the Framework Programmes of the EC for research, technological development and demonstration activities?
Authors: Suchý Václav , Škarka Martin , Vavříková Lucie , Hladík Petr , Lorenz Jaroslav
Published: February 2013

In-depth research of 56 Czech SMEs participating in projects funded under the thematic programmes of FP6 and FP7 was carried out in order to reveal the level of their involvement, the exploitation of research results and thus the benefits they gain from participation. Many SMEs cite indirect benefits, particularly networking with potential partners or customers and the improvements of their scientific, technological or managerial skills as the main values of project participation. More straightforward, market-oriented benefits such as introduction of new products or services onto the market, the increase of turnovers or other positive impacts on economic measures of performance after the project completion are, however, only rarely noted. Also, only a minor proportion of SMEs claim that their participation resulted in a new intellectual property subjected to formal protection (i.e. patents, industrial designs, utility models etc.). Many Czech micro- and small-size enterprises consider the overall effectiveness of the framework programmes questionable, complaining mainly on their unwieldy financial rules as well a significant administrative burden associated with the projects. The medium-size companies with more than 80-100 employees, on the other hand, tend to claim more satisfaction with the framework programmes. Nevertheless, when compared with existing national R&D programmes, many SMEs, regardless to their size, admit that the current FP scheme is less relevant to their actual needs and strategies.
Aspects Of Morbidity By Cancer For Women In Constanta County In Period 2007 - 2010
Authors: Severin Beatrice , Broască V. , Damaschin Floarea , Mocanu Elena , Chirilă S.
Published: February 2013

Breast cancer is the most frequently diagnosed cancer in women and cervical cancer is the second most common cancer worldwide. To analyze the cancer morbidity in women we used data taken from the reports of Public Health Department - Constanta during 2007-2010 and we calculated the incidence for different types of tumors. The study shows that for all years the values for incidence of breast and cervical cancers were double in rural areas compared with urban areas.
Surface tension of a liquid metal–oxygen system using a multilayer free energy model
Authors: Pajarre Risto , Koukkari Pertti , Tanaka Toshihiro
Published: February 2013

A constrained free energy model for an interfacial system of interacting layers is derived in the regular solution and Redlich–Kister formalisms. Composition and interfacial energies are solved using a model based on the minimisation of the total free energy of the system with a fixed interfacial area. As example cases iron–oxygen and copper–oxygen surfaces and liquid–liquid metal alloy interfaces are studied.
Mechanism of porosity growth during homogenisation in single crystal nickel-based superalloys
Authors: Epishin Alexander , Link Thomas , Svetlov Igor Leonidovich , Nolze Gert , Neumann Romeo Saliwan , Lucas Henning
Published: February 2013

Several mechanisms for porosity growth in single crystal nickel-based superalloys during homogenisation heat treatment have been proposed in the literature. They were carefully checked using different experimental methods, namely quantitative light microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and density measurements. It is shown that the main mechanism is the Kirkendall–Frenkel effect, i.e. generation of voids due to uncompensated efflux of Al atoms from dissolving γ/γ′-eutectic areas. The Al diffusion is supported by the afflux of vacancies from surrounding γ-matrix which results in porosity growth. This conclusion is confirmed by the estimation of the vacancy afflux towards the dissolving eutectic.
Congestion Probability and Traffic Volatility
Authors: Ossenbruggen Paul J. , Laflamme Eric M. , Linder Ernst
Published: February 2013

The primary purpose of this study is to understand better the roadway performance and the conditions that trigger congestion. Incidents of recurrent congestion were encountered at a location on New Hampshire Interstate 93 northbound, where radar measurements of speed were continuously recorded from April through November 2010. The root cause for the onset of congestion, both recurrent and nonrecurrent, is impossible to discern and explain by using exploratory data analyses alone; the data are too noisy. A time series modeling approach suggests that the magnitude of traffic flow and volatility, measured as the second (variance) and third (skewness) moments of flow residuals, can explain the triggering of congestion events for a highly variable environment that changes time by the time and day. The approach includes two types of mathematical models: generalized additive binomial probability models for roadway congestion that use functions of traffic flow and volatility as explanatory variables and functional data models that decompose and smooth traffic data to add insight to the roles that flow and volatility play in the congestion process. Most notably, the probability of congestion is shown to be a function of the short-term history of flow and volatility. The changes in these values—the first derivatives of flow and second and third moments of flow residuals derived from functional data model—are shown as well. Model selection, parameter estimation, and checking are presented.