bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reservoir permeability prediction by neural networks combined with hybrid genetic algorithm and particle swarm optimization
Authors: Ali Ahmadi Mohammad , Zendehboudi Sohrab , Lohi Ali , Elkamel Ali , Chatzis Ioannis 
Published: May 2012

ABSTRACTReservoir characterization involves describing different reservoir properties quantitatively using various techniques in spatial variability. Nevertheless, the entire reservoir cannot be examined directly and there still exist uncertainties associated with the nature of geological data. Such uncertainties can lead to errors in the estimation of the ultimate recoverable oil. To cope with uncertainties, intelligent mathematical techniques to predict the spatial distribution of reservoir properties appear as strong tools. The goal here is to construct a reservoir model with lower uncertainties and realistic assumptions. Permeability is a petrophysical property that relates the amount of fluids in place and their potential for displacement. This fundamental property is a key factor in selecting proper enhanced oil recovery schemes and reservoir management. In this paper, a soft sensor on the basis of a feed‐forward artificial neural network was implemented to forecast permeability of a reservoir. Then, optimization of the neural network‐based soft sensor was performed using a hybrid genetic algorithm and particle swarm optimization method. The proposed genetic method was used for initial weighting of the parameters in the neural network. The developed methodology was examined using real field data. Results from the hybrid method‐based soft sensor were compared with the results obtained from the conventional artificial neural network. A good agreement between the results was observed, which demonstrates the usefulness of the developed hybrid genetic algorithm and particle swarm optimization in prediction of reservoir permeability.
Computational elastic up‐scaling of sandstone on the basis of X‐ray micro‐tomographic images
Authors: Shulakova Valeriya , Pervukhina Marina , Müller Tobias M. , Lebedev Maxim , Mayo Sherry , Schmid Susanne , Golodoniuc Pavel , De Paula Osni Bastos , Clennell Michael B. , Gurevich Boris 
Published: May 2012

ABSTRACTUp‐scaling the elastic properties of digitized rock volumes as obtained from X‐ray computer tomography (CT) imaging via computer simulations has the potential to assist and complement laboratory measurements. This computational up‐scaling approach remains a challenging task as the overall elastic properties are not only dependent on the elastic properties of individual grains but also on the hardly resolvable pore spaces between adjacent grains such as micro‐cracks. We develop a digitized rock image and elastic up‐scaling workflow based on general‐purpose and widely available software packages. Particular attention is paid to CT image processing including filtering, smoothing and segmentation. A strategy for optimal meshing for subsequent finite‐element modelling is also proposed. We apply this workflow to the micro‐tomographic image of a well‐consolidated, feldspatic sandstone sample and determine the up‐scaled bulk and shear moduli. These effective elastic moduli are compared to the moduli inferred from laboratory ultrasound measurements at variable effective stresses (0–70 MPa). We observe that the numerically up‐scaled elastic moduli correspond to the moduli at a certain effective stress level (50 MPa), beyond which the effective‐stress dependency follows a linear trend. This indicates that the computational up‐scaling approach yields moduli as if all compliant (soft) porosity was absent, i.e., microcracks are closed. To confirm this hypothesis, we estimate the amount of soft porosity on the basis of the double‐porosity theory (Shapiro, 2003) and find that at 50 MPa the soft porosity is indeed practically zero. We conclude that our computational elastic up‐scaling approach yields physically consistent effective moduli even if some geometrical features are below CT resolution. To account for these sub‐resolution features either theoretical or additional computational approaches can be used.
Multisource least‐squares migration of marine streamer and land data with frequency‐division encoding
Authors: Huang Yunsong , Schuster Gerard T. 
Published: May 2012

ABSTRACTMultisource migration of phase‐encoded supergathers has shown great promise in reducing the computational cost of conventional migration. The accompanying crosstalk noise, in addition to the migration footprint, can be reduced by least‐squares inversion. But the application of this approach to marine streamer data is hampered by the mismatch between the limited number of live traces/shot recorded in the field and the pervasive number of traces generated by the finite‐difference modelling method. This leads to a strong mismatch in the misfit function and results in strong artefacts (crosstalk) in the multisource least‐squares migration image. To eliminate this noise, we present a frequency‐division multiplexing (FDM) strategy with iterative least‐squares migration (ILSM) of supergathers. The key idea is, at each ILSM iteration, to assign a unique frequency band to each shot gather. In this case there is no overlap in the crosstalk spectrum of each migrated shot gather m(x, ωi), so the spectral crosstalk product m(x, ωi)m(x, ωj) =δi, j is zero, unless i=j. Our results in applying this method to 2D marine data for a SEG/EAGE salt model show better resolved images than standard migration computed at about 1/10th of the cost. Similar results are achieved after applying this method to synthetic data for a 3D SEG/EAGE salt model, except the acquisition geometry is similar to that of a marine OBS survey. Here, the speedup of this method over conventional migration is more than 10. We conclude that multisource migration for a marine geometry can be successfully achieved by a frequency‐division encoding strategy, as long as crosstalk‐prone sources are segregated in their spectral content. This is both the strength and the potential limitation of this method.
Electrical properties and geochemistry of carbonate rocks from the Qasr El‐Sagha Formation, El‐Faiyum, Egypt
Authors: Abou El‐Anwar Esmat A. , Gomaa Mohamed M. 
Published: May 2012

ABSTRACTUnderstanding petrographical, geochemical and electrical properties of rocks is essential for investigating minerals. This paper presents a study of the petrographical, geochemical and A.C. electrical properties of carbonate rock samples. The samples collected show six lithostratigraphic rock units.Electrical properties were measured using a non‐polarizing electrode at room temperature (∼20°C) and a relative atmospheric humidity of ∼50% by weight in the frequency range from 42 Hz to 5 MHz. The difference in electrical properties between the samples was attributed to the change in composition and texture between the samples. Electrical properties generally change with many factors (grain size, chemical composition, grain shape and facies). The dielectric constant decreases with frequency and increases with conductor composition. The conductivity increases with the increase of conductor paths between electrodes. Many parameters can contribute to the same result of the electrical properties.The main objective of the present study is to shed more light on the relation between the texture and geochemical composition of measured samples (carbonates that contain clays and quartz grains) through electrical laboratory measurements (conductivity and dielectric constant as a function of frequency).
Presence and extent of histological tumour necrosis is an adverse prognostic factor in papillary type 1 but not in papillary type 2 renal cell carcinoma
Authors: Pichler Martin , Hutterer Georg C , Chromecki Thomas F , Pummer Karl , Mannweiler Sebastian , Zigeuner Richard 
Published: May 2012

Aims:  To date, only limited information is available on the prognostic significance of the presence and extent of histological tumour necrosis with regard to papillary renal cell carcinoma (RCC) types 1 and 2 subclassification. Thus, the aim of this study was to evaluate the prognostic impact of these pathological features on the clinical outcome in papillary subtypes.Methods and results:  The influence of histological tumour necrosis on the clinical outcome in 177 patients with papillary RCC was evaluated. For papillary subtype 1, the presence of histological tumour necrosis was an independent negative prognostic factor for disease‐free survival (P = 0.039), and a greater extent of necrosis (>20%) was significantly associated with both poor disease‐free and overall survival (P = 0.033 and P = 0.041, respectively). Regarding papillary subtype 2, neither the presence nor extent of histological tumour necrosis was a statistically significant negative prognostic factor.Conclusion:  Our findings suggest that the presence and extent of histological tumour necrosis are independent prognosticators in papillary RCC subtype 1, but not in papillary subtype 2. Thus, previously reported conflicting data regarding the prognostic impact of tumour necrosis in papillary RCC might be explained, in part, by heterogeneous subtypes.
Frequency and genetic characterization of V(DD)J recombinants in the human peripheral blood antibody repertoire
Authors: Briney Bryan S. , Willis Jordan R. , Hicar Mark D. , Thomas James W. , Crowe James E. 
Published: May 2012

SummaryAntibody heavy‐chain recombination that results in the incorporation of multiple diversity (D) genes, although uncommon, contributes substantially to the diversity of the human antibody repertoire. Such recombination allows the generation of heavy chain complementarity determining region 3 (HCDR3) regions of extreme length and enables junctional regions that, because of the nucleotide bias of N‐addition regions, are difficult to produce through normal V(D)J recombination. Although this non‐classical recombination process has been observed infrequently, comprehensive analysis of the frequency and genetic characteristics of such events in the human peripheral blood antibody repertoire has not been possible because of the rarity of such recombinants and the limitations of traditional sequencing technologies. Here, through the use of high‐throughput sequencing of the normal human peripheral blood antibody repertoire, we analysed the frequency and genetic characteristics of V(DD)J recombinants. We found that these recombinations were present in approximately 1 in 800 circulating B cells, and that the frequency was severely reduced in memory cell subsets. We also found that V(DD)J recombination can occur across the spectrum of diversity genes, indicating that virtually all recombination signal sequences that flank diversity genes are amenable to V(DD)J recombination. Finally, we observed a repertoire bias in the diversity gene repertoire at the upstream (5′) position, and discovered that this bias was primarily attributable to the order of diversity genes in the genomic locus.
Lung natural killer cells in mice: phenotype and response to respiratory infection
Authors: Wang Jian , Li Fengqi , Zheng Meijuan , Sun Rui , Wei Haiming , Tian Zhigang 
Published: May 2012

SummaryNatural killer (NK) cells have a specialized function in peripheral organs, which is determined by the organ‐specific niches. We have attempted to explore whether lung NK cells display a particular phenotype according to their function in the unique pulmonary environment in health or during respiratory infection in mice. In healthy mice, higher frequencies of NK cells among lymphocytes were detected in the lung than in other tissues (lymph node, bone marrow, spleen, blood and liver), and lung NK cells maintained a more mature phenotype, implying that lung NK cells were critical for the pulmonary immune response. However, lung NK cells expressed higher levels of inhibitory receptors and lower levels of activating receptors, migration/adhesion‐associated molecules and co‐stimulatory molecules than splenic NK cells, implying that lung NK cells were quiescent, and the activation of lung NK cells was tightly regulated by the pulmonary environment in health. During respiratory infection, lung NK cells could be activated and express functional molecules (CD107a and interferon‐γ) to take part in the response to infection quickly. These results suggested that the unique pulmonary environment promotes the development of NK cells with a lung‐specific phenotype.
Urinary phthalate excretion in 555 healthy Danish boys with and without pubertal gynaecomastia
Authors: Mieritz Mikkel G. , Frederiksen Hanne , Sørensen Kaspar , Aksglaede Lise , Mouritsen Annette , Hagen Casper P. , Skakkebaek Niels E. , Andersson Anna‐Maria , Juul Anders 
Published: May 2012

SummaryPubertal gynaecomastia is a clinical sign of an oestrogen‐androgen imbalance, which occurs in 40–60% of adolescent Caucasian boys. In most cases no underlying endocrinopathy can be identified. A recent study reports higher plasma phthalate levels in Turkish boys with pubertal gynaecomastia. Therefore, we asked whether there was an association between concurrent measures of urinary phthalate metabolites and pubertal timing as well as the presence of gynaecomastia in otherwise healthy boys. We studied a total of 555 healthy boys (age 6.07–19.83 years) as part of the COPENHAGEN Puberty Study. Anthropometry and pubertal stages (PH1‐6 and G1‐5) were evaluated, and the presence of gynaecomastia was assessed. Non‐fasting blood samples were analysed for serum testosterone and morning urine samples were analysed for the total content of 12 phthalate metabolites (MEP, MnBP, MiBP, MBzP, MEHP, MEHHP, MEOHP, MECPP, MiNP, MHiNP, MiONP and MCiOP) by LC‐MS/MS. A statistically significant negative correlation was observed between chronological age and the urinary concentration of the sum of measured metabolites DEHP (∑DEHPm) (r = −0.164) and DiNP (∑DiNPm) (r = −0.224), respectively, and the sum of monobutyl phthalate (MBP) isomers (∑MBP(i+n)) (r = −0.139) (all with p < 0.01). In contrast urinary monoethyl phthalate concentration was positively correlated to age (r = 0.187, p < 0.01). The urinary levels of phthalate metabolites were not associated with age at pubertal onset, serum testosterone levels or presence of gynaecomastia. In conclusion, we did not find evidence of anti‐androgenic effects of phthalates in our healthy boys. Thus, current phthalate exposure was not associated with pubertal timing, testosterone levels or with the presence of pubertal gynaecomastia in this cross‐sectional study. However, longitudinal studies are needed to evaluate possible perinatal or long‐term postnatal effects of phthalates on healthy boys.
Paracetamol (acetaminophen), aspirin (acetylsalicylic acid) and indomethacin are anti‐androgenic in the rat foetal testis
Authors: Kristensen D. M. , Lesné L. , Le Fol V. , Desdoits‐Lethimonier C. , Dejucq‐Rainsford N. , Leffers H. , Jégou B. 
Published: May 2012

SummaryMore than half the pregnant women in the Western world report taking mild analgesics. These pharmaceutical compounds have been associated with congenital cryptorchidism in humans, the best‐known risk factor for low semen quality and testicular germ cell cancer. Furthermore, some of these mild analgesics exert potent anti‐androgenic effects in the male rat and several endocrine‐disrupting compounds, known to alter masculinization, have also been shown to be potent inhibitors of prostaglandin (PG) synthesis similar to mild analgesics. Using a 3‐day ex vivo organotypic model system based on gestational day 14.5 rat testes, we herein show that testosterone production was inhibited by paracetamol, at doses of 0.1 μm to 100 μm. Similar results were obtained for aspirin (1–100 μm) and indomethacin (10 μm). The production of the other Leydig cell hormone, Insl3, was not disrupted by exposure to paracetamol. Investigations of the gross anatomy of the testis as well as Leydig cells number and rate of gonocyte apoptosis after the 3 days of ex vivo differentiation showed no significant effect of the analgesics tested compared with controls. These data indicate therefore that mild analgesics specifically inhibit testosterone production in rat foetal testes in vitro and that these compounds had no effect on gonocyte survival. Parallel determinations of prostaglandin D2 (PGD2) production indicated that the effects of paracetamol and aspirin on PGD2 and testosterone were not connected, whereas the effects of indomethacin were correlated. We conclude that mild analgesics exert direct and specific anti‐androgenic effects in rat foetal testis in our experimental setup and that the mechanism of action is probably uncoupled from the inhibition of PG synthesis.
Quick and dirty but still pretty good: a review of new descriptive methods in food science
Authors: Valentin Dominique , Chollet Sylvie , Lelièvre Maud , Abdi Hervé 
Published: May 2012

SummaryFor food scientists and industrials, descriptive profiling is an essential tool that involves the evaluation of both the qualitative and quantitative sensory characteristics of a product by a panel. Recently, in response to industrial demands to develop faster and more cost‐effective methods of descriptive analysis, several methods have been offered as alternatives to conventional profiling. These methods can be classified in three families: (i) verbal‐based methods (flash profile and check‐all‐that‐apply), (ii) similarity‐based methods (free sorting task and projective mapping aka Napping®) and (iii) reference‐based methods (polarised sensory positioning and pivot profile). We successively present these three classes of methods in terms of origin, principles, statistical analysis, applications to food products, variations of the methods and the Pros and Cons.
Changes in pigment profile and surface colour of fig (Ficus carica L.) during drying
Authors: Yemiş Oktay , Bakkalbaşı Emre , Artık Nevzat 
Published: May 2012

SummaryIn this study, anthocyanins in three fresh fig varieties (Ficus carica L.) cultivated in Turkey were characterised and quantified by HPLC/DAD and HPLC/MS. In addition, the carotenoid composition of Sarılop and Sarızeybek, yellow fig varieties, was determined, and then the ripening‐ and drying‐related changes in carotenoids and surface colour of figs were monitored during conventional sun‐drying. Four different anthocyanins, cyanidin‐3‐glucoside, cyanidin‐3,5‐diglucoside, cyanidin‐3‐rutinoside (major anthocyanin) and pelargonidin‐3‐glucoside, were identified in samples. Lutein, zeaxanthin, β‐cryptoxanthin and β‐carotene were carotenoids in yellow fig varieties. Approximately 80% of carotenoid compounds in yellow fig varieties degraded at the end of drying (i.e. seventh day). L (lightness), a (redness and greenness) and b (yellowness and blueness) colour parameters were measured by Hunter Lab system. Great changes in carotenoid composition and surface colour were observed at ripening stage on tree. A significant reduction in L and b values that refers to browning in figs was made in the first 3 days of drying process.
Relationships between colour parameters, phenolic content and sensory changes of processed blueberry, elderberry and blackcurrant commercial juices
Authors: Casati Carolina B. , Sánchez Virginia , Baeza Rosa , Magnani Natalia , Evelson Pablo , Zamora María C. 
Published: May 2012

SummaryThere is an increased interest in the consumption of fruits containing high phenolic concentrations such as berry fruits. Attractive colour of berries plays a vital role for consumer acceptance. The aim of this work was to evaluate colour parameters (a*, b*, L*), phenolic content and sensory changes of blueberry, elderberry and blackcurrant (BC) pasteurised commercial juices during accelerate storage. Initial phenolic concentration was 3.21, 10.06, 10.72 g GAE L−1 for blueberry, elderberry and BC, respectively. Moreover, phenolic concentration of all juices decreased by approximately 40% throughout the first 30 days. Blueberry exhibited a substantial decrease in a* (40%) in the first 30 days, while elderberry presented a gradual decrease and BC only presented a slight decrease (7%) at the end of storage. Colour preferences decreased when storage time increased. However, when consumers were informed that ‘the juices are a rich source of phenolics, which contribute to reducing risk of suffering chronic diseases’, a high level of purchase intention was obtained.
Pharmacokinetics of pioglitazone in lean and obese cats1
Authors: CLARK M. H. , HOENIG M. , FERGUSON D. C. , DIRIKOLU L. 
Published: May 2012

Clark, M. H., Hoenig, M., Ferguson, D. C., Dirikolu, L. Pharmacokinetics of pioglitazone in lean and obese cats. J. vet. Pharmacol. Therap. 35, 428–436.Pioglitazone is a thiazolidinedione insulin sensitizer that has shown efficacy in Type 2 diabetes and nonalcoholic fatty liver disease in humans. It may be useful for treatment of similar conditions in cats. The purpose of this study was to investigate the pharmacokinetics of pioglitazone in lean and obese cats, to provide a foundation for assessment of its effects on insulin sensitivity and lipid metabolism. Pioglitazone was administered intravenously (median 0.2 mg/kg) or orally (3 mg/kg) to 6 healthy lean (3.96 ± 0.56 kg) and 6 obese (6.43 ± 0.48 kg) cats, in a two by two Latin Square design with a 4‐week washout period. Blood samples were collected over 24 h, and pioglitazone concentrations were measured via a validated high‐performance liquid chromatography assay. Pharmacokinetic parameters were determined using two‐compartmental analysis for IV data and noncompartmental analysis for oral data. After oral administration, mean bioavailability was 55%, t1/2 was 3.5 h, Tmax was 3.6 h, Cmax was 2131 ng/mL, and AUC0–∞ was 15 556 ng/mL·h. There were no statistically significant differences in pharmacokinetic parameters between lean and obese cats following either oral or intravenous administration. Systemic exposure to pioglitazone in cats after a 3 mg/kg oral dose approximates that observed in humans with therapeutic doses.
Reconstruction of caribou evolutionary history in Western North America and its implications for conservation
Authors: WECKWORTH BYRON V. , MUSIANI MARCO , McDEVITT ALLAN D. , HEBBLEWHITE MARK , MARIANI STEFANO 
Published: May 2012

AbstractThe role of Beringia as a refugium and route for trans‐continental exchange of fauna during glacial cycles of the past 2 million years are well documented; less apparent is its contribution as a significant reservoir of genetic diversity. Using mitochondrial DNA sequences and 14 microsatellite loci, we investigate the phylogeographic history of caribou (Rangifer tarandus) in western North America. Patterns of genetic diversity reveal two distinct groups of caribou. Caribou classified as a Northern group, of Beringian origin, exhibited greater number and variability in mtDNA haplotypes compared to a Southern group originating from refugia south of glacial ice. Results indicate that subspecies R. t. granti of Alaska and R. t. groenlandicus of northern Canada do not constitute distinguishable units at mtDNA or microsatellites, belying their current status as separate subspecies. Additionally, the Northern Mountain ecotype of woodland caribou (presently R. t. caribou) has closer kinship to caribou classified as granti or groenlandicus. Comparisons of mtDNA and microsatellite data suggest that behavioural and ecological specialization is a more recently derived life history characteristic. Notably, microsatellite differentiation among Southern herds is significantly greater, most likely as a result of human‐induced landscape fragmentation and genetic drift due to smaller population sizes. These results not only provide important insight into the evolutionary history of northern species such as caribou, but also are important indicators for managers evaluating conservation measures for this threatened species.