bluuebunny/crossref_metadata_2025 huggingface dataset:
A Coupled Approach to Simulate the Explosion Response of a Buried Structure in a Soil-Rock Layered Medium
Authors: Feldgun V.R. , Karinski Y.S. , Yankelevsky D.Z.
Published: October 2013

The paper presents an investigation on the response of a buried structure in a soft soil layer above a rock bed that is subjected to blast loading. A comprehensive approach to simulate the behavior of soft soil with a buried structure laying over a rock mass due to the dynamic (explosive) action in the rock mass is presented. The numerical algorithm was developed to simulate the shock wave propagation within the medium, considering both the bulk and deviatoric damage and taking into account the possible shear damage accumulation. It takes into account the contact conditions between the layers to simulate the shock wave transmission and the soil-structure interaction including their possible separation. The soil-lining interaction problem is solved by a combination of the variational-difference method (for the lining) and of the Godunov's method (for the soil). The coupling of these two approaches is performed by calculation of the contact stresses and velocities on the soil-lining boundary. Two types of the soil models were investigated – an ideal elastic plastic medium and an irreversible compressible medium with failure in bulk tension – and the results were compared with each other. The analysis of the free surface and interface velocities and displacements as well as the contact stresses and the damage at the media interface were carried out. The effects of the relative cover thickness on the interface and free surface behavior is studied. Analysis of the contact stresses at the soil-tunnel interface, was carried out. The effect of the charge location as well as the effect of the soil-rock interface on the tunnel's response was investigated.
Defining Erosion Limit for Concrete
Authors: Luccioni Bibiana M. , Aráoz Gabriel F. , Labanda Nicolás A.
Published: October 2013

Numerical simulation is usually used for predicting the response of concrete and fiber reinforced concrete structures to blast or impact loads. Depending on both charge weight and standoff distance, blast loads can cause fracture and spalling of concrete. In order to numerically reproduce these effects, an erosion model can be used to remove from the calculation the elements that have reached certain criteria. This erosion model represents a numerical tool to avoid great distortion of Lagrange meshes. For this reason, its application to the simulation of a physical phenomenon requires the calibration with experimental results. A review of different erosion criteria and limits used by different authors to simulate concrete under blast loads is presented in this paper. Some application examples and comparisons with experimental results are developed to show the effect of erosion limit on damage results and the dependence on the materials properties, mesh size and scaled distance.
A Comparative Study of Modelling RC Slab Response to Blast Loading with Two Typical Concrete Material Models
Authors: Xu Jiaming , Lu Yong
Published: October 2013

The soundness of numerical simulation for reinforced concrete structures under blast loading is closely related to the capacity of the concrete models in dealing with the nonlinear behaviour of the material under complex stress conditions. To understand more comprehensively the demands a rigorous simulation may impose on a modelling approach and thereby the needs for improvement in the model formulation, a comparative numerical simulation study has been conducted in which two representative concrete material models, namely KCC and CSC models in LS-DYNA, are employed to model a typical RC slab subjected to blast load. For such a classical modelling situation, the model with KCC concrete material tends to fail prematurely with a total global failure of the slab, which is not consistent either with the experimental observations or with the CSC modelling results. Extensive analysis of the failure processes reveals that the abnormal response in the KCC model is linked to the rapid descending of the material model behaviour towards an effectively zero stress state following a tension/shear controlled damage process, and the consequent diminish of the interaction capacity between the steel rebar and the surrounding concrete. The findings from this study point a direction in which certain rectification will need to be considered in order to ensure a reliable modelling outcome with the KCC type concrete models in simulating the response of RC structures, both globally and locally.
Aramid Fiber Sheet Reinforcing Effects on the Local Damage in Concrete Plates Subjected to High Velocity Impact
Authors: Beppu Masuhiro , Kataoka Shinnosuke , Takahashi Jun , Krauthammer Theodor
Published: October 2013

This study intended to evaluate the effectiveness of fiber sheet reinforcement on local damage mitigation in concrete plates subjected to high velocity impact. High velocity impact tests were conducted using concrete plates externally reinforced with aramid fiber sheets to examine the effects of the number of the fiber sheet laminates on the local damage. In a series of impact tests, strain time histories of the fiber sheet laminates were measured. Numerical simulations using the hydrocode ANSYS AUTODYN were carried out to reproduce the reinforcing effects by the fiber sheet laminates. Numerical results are discussed by comparing strain behavior and failure simulated numerically with test results. The reinforcing mechanism by the fiber sheets is discussed based on the numerical results.
Issues with data transformation in genome-wide association studies for phenotypic variability
Authors: Shen Xia , Rönnegård Lars
Published: October 2013

The purpose of this correspondence is to discuss and clarify a few points about data transformation used in genome-wide association studies, especially for phenotypic variability. By commenting on the recent publication by Sun et al. in the American Journal of Human Genetics, we emphasize the importance of statistical power in detecting functional loci and the real meaning of the scale of the phenotype in practice.
Teaching Note—Forecasting Beer Demand at Anadolu Efes
Authors: Köksalan Murat , Özpeynirci Selin , Süral Haldun
Published: September 2013

Case Teaching Note: Interested Instructors please see the Instructor Materials page for access to the restricted materials. To maintain the integrity and usefulness of cases published in ITE, unapproved distribution of the case teaching notes and other restricted materials to any other party is prohibited.
SYSTEMATIC APPROACH TO THE STABLE IMPLEMENTATION OF REGIONS SOCIAL-ECONOMIC DEVELOPMENT
Authors: Azimov Shukhrat
Published: October 2013

The article is dedicated to the analysis of the importance of systematic approach of the social-economical development in accordance with its generality, regionality, comparability, and logicality characteristics. There has been also given ideas about the importance of ‘nature-population-household-nature’ cycle in the stable ecological-social-economical development.
Improving The Mechanism For The Participation Of Banks In The Restructuring Of Joint-Stock Enterprises In The Cis.
Authors: Kotov Valentin
Published: October 2013

This article focuses on the participation of commercial banks in the CIS in providing the investment processes of restructuring of joint-stock companies. The features of the investment bank providing various types of modernization of companies, as well as the risks associated with the implementation of their functions as consultants, institutional investors, investment brokers and asset managers, trust companies. The content of the mechanism of action of banks to scale up and improve the quality of the investment programs to ensure the restructuring of joint-stock companies.
Integration Process Of Slovakia Into The European Monetary Union In Perspective Of Selected Macro-Economic Theories During The Current Economic Crisis
Authors: Kotuliè Rastislav
Published: October 2013

Each national economy anticipates mostly positive effects after joining the Euro. Positive expectations are logical, since every new country admitted to the EU pledges to join the Monetary Union  and till the admission  has the status of a member state with a temporal exemption for the joining of the Euro. According to the macro­economic results, there is usually  an illusion  present that the membership  in  the Eurozone itself absorbs the progress of the global recession. On  the other hand, in  favor  of  the membership  in  the Eurozone speaks the fact that all countries admitted had to rigidly fulfill the Maastricht Convergence Criteria leading to the medium­term guarantee of  a healthy and long­term sustainable economy.
Legal Status Of The Caspian Sea: History And Present
Authors: Kapyshev Ardak
Published: October 2013

At  the  present  stage  one  of  the  unsolved   problems in  interstate relations of  Caspian bordering countries is defining international­legal status of the Caspian Sea. It is noted in the article that this problem is not a new one at all. The history of “division” of the Caspian Sea begins in the ancient age, namely in VIII century. It is underlined that the basic stumbling block  is the position of Iran on the right to use the Caspian Sea, and also occurrence of extra regional players, such as  the USA, China, etc. First of  all, it is connected with rich oil fields and other minerals, and also with convenient geopolitical and geostrategic position. The only way to worry out the international­legal delimitation of the Caspian Sea problem is a negotiating process. By now, despite of  certain disagreements on  legal status of  the Caspian Sea, five Caspian bordering countries managed to achieve certain progress, admitting the possibility of applying the principle of sectorial sectioning on the Caspian Sea.  Clear proof  of  it is the agreements on  division of ground on the northern part of Caspian Sea signed between Kazakhstan, Russia and Azerbaijan. It is important that Kazakhstan, Russia, Azerbaijan and Turkmenistan clearly stated their positions and agreed to make a compromise in their official statements. More than likely, in the near future Iran will soften its position, considering its present  situation and   strained relations with the USA. It has been alleged that the constructive  dialog  already  started; everything depends on  the mobility,  concurrency and rationality of actions of all Caspian bordering countries.
Role of social media in brand development in Saudi Arabia
Authors: Al Saud Abeer Abdullah , Khan Muhammad Rahatullah
Published: October 2013

Literature is ripe with the scholarly contributions on brand development from all aspects. The new marketing tools and techniques are introduced frequently. However, the impact social media has had on brand development is no match to traditional promotion in 4Ps. The information about Saudi Arabia is specially rare. This article based on a survey of 200 social media users on www.surveymonkey.com evaluates the role of social media in brand development in Saudi Arabia. The results from this Saudi example show that social media including Facebook and Twitter are among the most effective tool to develop a brand as compared to traditional promotional methods. It has also been found that these media are more successful in Saudi Arabia to develop the brand recall and image.
Neuroprotection In Chronic Brain Ischemia: Clinical And Immunological Features
Authors: Madjidova Yakutkhon , Usmanova Durdona
Published: October 2013

The influence of neuroprotectorcortexin with significant immunomodulating, anti-inflammatory, neurotrophic, and neuroprotective effects on subjective and neurological symptoms, as well as immunological parameters (IL-1β,TNF-a) in chronic brain ischemia is shown in the article.
Liver Mitochondrial Enzyme System In The Dynamics Of Experimental Leukemia
Authors: Kasymova Gulmira , Zaribbaev Ulugbek
Published: October 2013

In rats with leukemia activity of liver mitochondrial enzymes are decreased at 6 months. Later, we noted compensatory activation of complexes II and III of the respiratory chain and transition to decompensation stage by final deadline. The activity of complex IV of the respiratory chain remains high. These changes result from increased lipid peroxidation and decreased activity of antioxidant protection enzymes.
Clinical And Factorial Analysis Of Pathological States In Acute Intestinal Infections In Children
Authors: Shadjalilova Mukarram
Published: October 2013

The author reported clinical characteristic features and risk factors for acute intestinal infections in 225 children (140 boys and 85 girls, mean age 1.5 years old). 90 (40%) patients aged up to 12 months, 101 (44.9%) were from 1 to 2 years old, and 34 (15.1%) were more than 2 years old. Most children were hospitalized in the first week of illness and had moderate severe course of disease. Severe forms of illness reliably more often were noted in children being on artificial feeding. Toxic-dystrophic condition, severe forms and perinatal encephalopathy were prevailed in boys. Factorial analysis revealed 20 most significant factors with factorization fullness 70.8%. The most significant factors were F-1(factor of hyperthermia duration) with 8.5% effect, F-2 (factor of pain syndrome) – 5.8%, F-3 (factor of normal enzymatic activity of colon bacillus) – 4.9%, F-4 (etiological factor) – 4.6%, as well as F-5(factor of opportunistic flora of the intestine) – 4.4%, respectively.
Numerical Research Of Nonlinear Vibrations Of Isotropic Viscoelastic Plates With Variable Rigidity By The Method Of Computer Simulation
Authors: Abdikarimov Rustam
Published: October 2013

In the given work the problem about vibrations of a isotropic viscoelastic plate with  variable rigidity in  geometrically nonlinear statement is considered. With the help of Bubnov-about nonlinear vibrations of viscoelastic isotropic plate in geometrically  nonlinear  statement  on  Kirchhoff-Love’s kinematic  hypothesis,  physical  dependence  between. Galerkin method the problem is reduced to the decision of system of nonlinear ordinary integro-differential equations of Volterra’s type. The numerical method based on the use of quadrature formulas is applied for the decision of the received system at weakly singular kernel of Koltunov- Rzhanitsin’s. Influences of  viscoelastic properties of  a material, geometrical characteristics, and also dependences.
MULTISUBJECT PERSONALITY DEVELOPMENT AS A PROMISSING AREA OF EVERYDAY SOCIAL AND CULTURAL ACTIVITIES AND ADDITIONAL EDUCATION FOR ADULTS
Authors: Kuznetsova Elena
Published: October 2013

Based on presumption of insufficient vocational training for adults, the author focuses on the possibility of restructuring the system of additional vocational training for adults. As a result, the author considering improvement in this area, states it is necessary to take into account unavoidable mental transformations of participants carrying national self-consciousness.
The concentration of high-sensitivity troponin I, galectin-3 and NT-proBNP substantially increase after a 60-km ultramarathon
Authors: Salvagno Gian Luca , Schena Federico , Gelati Matteo , Danese Elisa , Cervellin Gianfranco , Guidi Gian Cesare , Lippi Giuseppe
Published: October 2013

The leading mechanisms responsible for the most prevalent and serious cardiac injuries include myocardiocyte stretch, myocardiocyte necrosis and cardiac fibrosis, which can now be reliably mirrored by measurement of natriuretic peptides, cardiospecific troponins and galectin-3, respectively. Although a large amount of knowledge has been gathered about the behavior and clinical significance of these biomarkers in patients with cardiac disorders, less information is available on their biology in paraphysiological conditions, including high-intensity endurance exercise.

The study population consisted of 18 trained athletes, who performed a 60-km ultramarathon run. Blood was collected before the run (i.e., “baseline”) and immediately after the end of the ultramarathon (“post-marathon”) for measurement of serum high-sensitivity troponin I (TnI), NT-proBNP and galectin-3.

The concentration of all biomarkers measured in the post-marathon samples was remarkably increased as compared with the values obtained on baseline specimens. In particular, the median increase was 3.3 for TnI, 3.5 for NT-proBNP and 2.4 for galectin-3, respectively. The frequency of values exceeding the diagnostic threshold did not differ at baseline and after the ultramarathon for TnI (6% vs. 25%; p=0.15), instead was significantly increased for NT-proBNP (0% vs. 28%; p=0.016) and galectin-3 (0% vs. 67%; p<0.001). No significant correlation was found among the increase of any of the three biomarkers.

The results of this study demonstrate that high-intensity endurance exercise is associated with biochemical abnormalities that may reflect adverse consequences on cardiac structure and biology.
The Orbitofrontal Cortex as Part of a Hierarchical Neural System Mediating Choice between Two Good Options
Authors: Keiflin Ronald , Reese Rebecca M. , Woods Catherine A. , Janak Patricia H.
Published: October 2013

Animals rely on environmental cues to identify potential rewards and select the best reward available. The orbitofrontal cortex (OFC) is proposed to encode sensory-specific representations of expected outcome. However, its contribution to the selection of a preferred outcome among different reward options is still unclear. We investigated the effect of transient OFC inactivation (achieved by presession injection of muscimol and baclofen) in a novel two-reward choice task. In discrete trials, rats could choose between a solution of polycose and an equally caloric, but highly preferred, solution of sucrose by visiting one of two liquid dispensers after the presentation of a specific cue signaling the availability of one or both of the solutions. We found that OFC inactivation did not affect outcome preference: rats maintained high preference for sucrose and adapted their behavioral responding when the cue–outcome contingencies were reversed. However, when rats were tested drug-free 24 h after OFC inactivation and reversal learning, memory for the newly learned contingencies was poor. These results suggest a potential conflict between OFC (encoding pre-reversal contingencies) and other brain circuits (encoding the new contingencies). Remarkably, repeating the OFC inactivation before the reversal memory test restored normal behavior, confirming the hypothesis of a dominant impact of OFC on other decision-making circuits. These results indicate that the representations encoded in the OFC, while not essential to the expression of outcome preference, exert hierarchical control on downstream decision-making circuits.
Pea3 Transcription Factor Family Members Etv4 and Etv5 Mediate Retrograde Signaling and Axonal Growth of DRG Sensory Neurons in Response to NGF
Authors: Fontanet Paula , Irala Dolores , Alsina Fernando C. , Paratcha Gustavo , Ledda Fernanda
Published: October 2013

Nerve growth factor (NGF) is a target-derived neurotrophic growth factor that controls many aspects of sensory and sympathetic neuronal development. The identification of transcription factors and downstream target genes that mediate NGF-dependent neuronal differentiation and target field innervation is currently a major challenge. Here, we show that the Pea3 transcription factor family members Etv4 and Etv5 are expressed by developing TrkA-positive dorsal root ganglion (DRG) neurons during the period of target innervation. Real-time PCR assays indicated thatEtv4andEtv5mRNAs are significantly induced by NGF in different neuronal cells, suggesting that they could be involved in the biological responses induced by this neurotrophin. Interestingly, distal axon application of NGF in compartmentalized cultures of rat DRG sensory neurons was sufficient to induce a significant increase inEtv4andEtv5mRNA expression. Pharmacological assays also revealed that activation of MEK/ERK (MAPK) pathway is required forEtv4andEtv5gene induction in response to NGF. Downregulation of Etv4 and Etv5 using small interference RNA knockdown experiments inhibited NGF-induced neurite outgrowth of rat sensory neurons, while overexpression of full-length Etv4 or Etv5 potentiated neuronal differentiation in response to this neurotrophin. Together, these data establish Etv4 and Etv5 as essential molecules of the transcriptional program linking neurotrophin signaling to sensory neuronal differentiation, and suggest that they can be involved in NGF-mediated target innervation.
Shank3 Deficiency Induces NMDA Receptor Hypofunction via an Actin-Dependent Mechanism
Authors: Duffney Lara J. , Wei Jing , Cheng Jia , Liu Wenhua , Smith Katharine R. , Kittler Josef T. , Yan Zhen
Published: October 2013

Shank3, which encodes a scaffolding protein at glutamatergic synapses, is a genetic risk factor for autism. In this study, we examined the impact of Shank3 deficiency on the NMDA-type glutamate receptor, a key player in cognition and mental illnesses. We found that knockdown of Shank3 with a small interfering RNA (siRNA) caused a significant reduction of NMDAR-mediated ionic or synaptic current, as well as the surface expression of NR1 subunits, in rat cortical cultures. The effect of Shank3 siRNA on NMDAR currents was blocked by an actin stabilizer, and was occluded by an actin destabilizer, suggesting the involvement of actin cytoskeleton. Since actin dynamics is regulated by the GTPase Rac1 and downstream effector p21-activated kinase (PAK), we further examined Shank3 regulation of NMDARs when Rac1 or PAK was manipulated. We found that the reducing effect of Shank3 siRNA on NMDAR currents was mimicked and occluded by specific inhibitors for Rac1 or PAK, and was blocked by constitutively active Rac1 or PAK. Immunocytochemical data showed a strong reduction of F-actin clusters after Shank3 knockdown, which was occluded by a PAK inhibitor. Inhibiting cofilin, the primary downstream target of PAK and a major actin depolymerizing factor, prevented Shank3 siRNA from reducing NMDAR currents and F-actin clusters. Together, these results suggest that Shank3 deficiency induces NMDAR hypofunction by interfering with the Rac1/PAK/cofilin/actin signaling, leading to the loss of NMDAR membrane delivery or stability. It provides a potential mechanism for the role of Shank3 in cognitive deficit in autism.
Chronic Cocaine Dampens Dopamine Signaling during Cocaine Intoxication and Unbalances D1over D2Receptor Signaling
Authors: Park Kicheon , Volkow Nora D. , Pan Yingtian , Du Congwu
Published: October 2013

Dopamine increases triggered by cocaine and consequent stimulation of dopamine receptors (including D1and D2) are associated with its rewarding effects. However, while facilitation of D1receptor (D1R) signaling enhances the rewarding effects of cocaine, facilitation of D2R signaling decreases it, which indicates that for cocaine to be rewarding it must result in a predominance of D1R over D2R signaling. Moreover, the transition to compulsive cocaine intake might result from an imbalance between D1R and D2R signaling. To test the hypothesis that chronic cocaine use unbalances D1R over D2R signaling during cocaine intoxication, we used microprobe optical imaging to compare dynamic changes in intracellular calcium ([Ca2+]i, marker of neuronal activation) to acute cocaine in striatal D1R-EGFP and D2R-EGFP-expressing neurons between control and chronically treated mice. Chronic cocaine attenuated responses to acute cocaine in D1R (blunting Ca2+increases by 67 ± 16%) and D2R (blunting Ca2+decrease by 72 ± 17%) neurons in most D1R and D2R neurons (∼75%). However, the dynamics of this attenuation during cocaine intoxication was longer lasting for D2R than for D1R. Thus, whereas control mice showed a fast but short-lasting predominance of D1R over D2R signaling (peaking at ∼8 min) during acute cocaine intoxication, in chronically treated mice D1R predominance was sustained for >30 min (throughout the measurement period). Thus, chronic cocaine use dramatically reduced cocaine-induced DA signaling, shifting the balance between D1R and D2R signaling during intoxication to a predominance of D1R (stimulatory) over D2R (inhibitory) signaling, which might facilitate compulsive intake in addiction.
Extensive hydroa vacciniforme
Authors: Almeida Jr Hiram Larangeira de , Kopp Janaína , Jorge Valeria Magalhães , Sartori Debora Sarzi , Velloso Carolina Dahmer
Published: October 2013

Hydroa Vaciniforme is a very rare photodermatosis that is mainly seen in childhood. An 18 year old female student reported that since the age of 5 she has been suffering necrotic lesions and vesicles lesions in exposed areas, leaving asymptomatic varioliform scars, which worsened in summer. Light microscopy showed epidermal necrosis with lymphocytic infiltration . Sunscreens were prescribed with light improvement.
Epidemiological and histopathological profile of cutaneous melanoma at a center in northeastern Brazil from 2000 to 2010
Authors: Vilanova Camila Maria Arruda , Lages Rafael Bandeira , Ribeiro Sahâmia Martins , Almeida Isabella Parente , Santos Lina Gomes dos , Vieira Sabas Carlos
Published: October 2013

BACKGROUND: While representing only 3-4% of malignant skin tumors, cutaneous melanoma is the most aggressive and lethal. Statistical knowledge about the biological behavior of this tumor is essential for guiding daily outpatient practice and aiding public health policies.OBJECTIVES: To analyze the profile of patients with cutaneous melanoma attending a pathology department in Teresina (state of Piauí) between 2000 and 2010.METHODS: Retrospective study of melanoma patients diagnosed between 2000 and 2010 in the São Marcos Hospital in the city of Teresina. The pathology laboratory reports were studied and all the statistical analyses performed using SPSS 19.0.RESULTS: A total of 25 in situ, 199 invasive and 89 metastatic melanomas of unknown primary site were observed. Histological types found were nodular (52.8%), superficial spreading melanoma (18.6%), acral (10.6%) and lentigo maligna (9.5%). In 144 (73.4%) cases the Breslow thickness was >1 mm. Metastasis was found in 28.6% of invasive melanomas and nodular melanoma, Clark IV/ V, Breslow > 1 mm, mitotic index > 6 and ulcerated lesions were more likely to metastasize.CONCLUSION: Most melanomas presented Breslow> 1mm. The main factors associated with metastasis were nodular type, Clark IV / V, Breslow> 1mm, mitotic index > 6 and ulcerated lesions.
Soft-tissue masses as presentation of non-Hodgkin's lymphoma in AIDS patients
Authors: Corti Marcelo , Villafane Maria Florencia , Bistmans Alicia , Campitelli Ana , Narbaitz Marina
Published: October 2013

Primary soft tissue Non-Hodgkin lymphomas are very rare and account only for 0.1 % of the cases. Generally, Non-Hodgkin lymphomas of the soft tissue present as large subcutaneous masses without evidence of nodal or skin involvement. We describe four cases of primary Non-Hodgkin lymphomas of the soft tissue in patients infected with the human immunodeficiency virus. The most common site of involvement was the chest wall in all the patients; histopathological and immunophenotypic examination of the biopsy smears revealed two cases of plasmablastic lymphomas, one Burkitt and one diffuse large B-cell lymphoma. Non-Hodgkin lymphomas should be included in the differential diagnosis of soft tissue masses in human immunodeficiency virus - seropositive patients.
Structural performance evaluation of circular steel bands for PC column–beam connection
Authors: Kim Jeom Han , Cho Young Sang , Lee Kyung Hun
Published: October 2013

The aim of this study was to evaluate the performance of steel bands used for connecting centrifugal hollow precast concrete (PC) columns to steel beams. A steel band and centrifugal hollow PC column were connected together to produce specimens using two methods: stud bolt connection and rib connection. While the stud bolt connecting method produces interference between the stud bolt and column rebar structure during the production of a centrifugal hollow PC column, causing a delay in the process, the rib connecting method does not cause interference with the rebar structure, simplifying the production process. The results of the study indicated that, compared with the stud bolt connecting method, the specimen produced by the rib connecting method produced a 12·8% greater yield strength and a 9·7% greater horizontal displacement. The strain of the steel band was 0·0013 until the inter-floor displacement angle reached 0·04 rad, and thus the steel band remained in elastic regions even after significant deformation occurred at the joint.
Thermoregulation: Cytokines Involved in Fever and Exercise
Authors: Johnson Rowsey Pamela
Published: September 2013

The study of fever has provided important models in understanding the cells, chemical messengers, and anatomic structures that are involved in inflammation and thermoregulation as a result of infection, stress, or trauma. After contact with a pathogen or an inflammatory stimulus, cells are activated to produce endogenous pyrogens called cytokines. Cytokine functions include a cascade of nonspecific immune responses by target leukocytes and reticuloendothelial cells inducing the synthesis of acute phase proteins by the liver, direct pyrogenic activities via the supraoptic nuclei and the hypothalamus to increase the thermoregulatory set-point (and, thus, induce fever), and a wide spectrum of additional immune effects.
Exercise and Cancer
Authors: Knobf M. Tish , Winters-Stone Kerri
Published: September 2013

There are an estimated 13.7 million cancer survivors in the United States. Persistent and late effects of cancer therapy have contributed to an increased risk for co-morbid illness and higher all-cause mortality. Physical exercise is a targeted rehabilitative intervention following cancer therapy and a health promotion risk reduction intervention for patients as they transition into survivorship. This chapter provides a brief overview of the research on exercise and cancer survivor outcomes with a specific focus on randomized controlled trials (RCT) on the effects of exercise on body composition and bone health. There were 17 RCT trials that were identified with body composition outcomes. There was no change in weight in 16/17 trials, 4 reported decreases in percent fat mass and 2 reported increases in lean mass. Eight exercise trials were identified with bone outcomes, two of which had pharmacologic comparison arms. These trials demonstrated preservation of bone in the intervention group compared with loss in the usual care or placebo control group. The majority of trials were with breast cancer survivors, the largest survivor group. Many are overweight or obese at diagnosis; weight gain continues to increase after therapy; and treatment is associated with bone loss. The findings of the 25 trials reviewed suggest that exercise maintains weight and bone mass in a high risk population. However, differences in design, measurement of body composition and bone mass and lack of targeted exercise to the specific outcomes warrants additional research to improve the quality of life for survivors.
Flow Analysis: A Critical Step in Completion Design and Optimization. A Case Study of Multizone Completion Designs
Authors: Pogoson Oje , Cardona Andres
Published: September 2013

Multizone completion systems are used worldwide as an efficient method to maximize reserves recovery. There are several assets in the deepwater Gulf of Mexico where this technology is the preferred option for optimizing drainage of multiple zones and/or reservoirs in the same well completion. However, the selection and design of these completions demand specialized evaluations of completion equipment, analysis of fluid properties and operating conditions, not only to maximize production but also to ensure the reliability of the completion system.

The scope of this study covers completion design configurations and flow analysis for a well intersecting three zones (reservoirs), using completion data, fluid and reservoir properties to evaluate expected well production and completion reliability. Four completion design options were evaluated: one x dual zone and three x triple zone completions, each with a different flow configuration.

The analysis adopted considers the entire completion system including fluid flow paths and actual dimensions of equipment and their position in relation to other equipment. The objective is to calculate the maximum production rate through a completion system based on erosion assessment, and also evaluate the pressure loss at defined production rates. Production scenario calculations were also performed at defined wellhead pressures.

Flow analysis results show that the evaluated design options each offered unique capabilities based on a set of defined completion and production constraints. Each completion design exhibits different flow capacities with pressure loss variances. Results also identified sections within the completion systems where dimensions or other physical properties of equipment can be optimized to maximize the flow of produced fluid, and minimize the potential for erosion.

This study identifies a methodology for completion design and optimization during field development planning and management. It provides valuable information and decision tools for reservoir (drawdown, flow rates, and fluid behavior conditions) production (flow rates and flow assurance) and completion engineering teams (optimized completion design, pressure, temperature and erosion parameters).
Characterizing Hydraulic Fracturing with a Tendency for Shear Stimulation Test
Authors: McClure Mark , Horne Roland
Published: September 2013

The classical concept of hydraulic fracturing is that a single, planar, opening mode fracture propagates through the formation. In recent years, there has been a growing consensus that natural fractures play an important role during stimulation in many settings. There is not universal agreement on the mechanisms by which natural fractures affect stimulation, and these mechanisms may vary depending on formation properties. One potentially important mechanism is shear stimulation, where increased fluid pressure induces slip and permeability enhancement on preexisting fractures. We propose a tendency for shear stimulation (TSS) test as a direct, relatively unambiguous method for determining the degree to which shear stimulation contributes to stimulation in a formation. In a TSS test, fluid is injected at a bottomhole pressure that is maintained below the minimum principal stress. Under these conditions, shear stimulation is the only possible mechanism for permeability enhancement (except perhaps thermally induced tensile fracturing). Standard pressure transient tests could be performed before and after the TSS test to estimate formation permeability. The flow rate transient during injection may also be interpreted to identify shear stimulation. Numerical simulations of shear stimulation were performed with a discrete fracture network (DFN) simulator that couples fluid flow with the stresses induced by fracture deformation. These simulations were used to qualitatively investigate how shear stimulation and fracture connectivity affect the results of a TSS test. Two specific field projects are discussed as examples of a TSS test, the Enhanced Geothermal Systems (EGS) projects at Desert Peak, Nevada and Soultz-sous-Forêts, France.
Deconvolution of Well Test Data in Lean and Rich Gas Condensate, and Volatile Oil Wells below Saturation Pressure
Authors: Ogunrewo O. , Gringarten A. C.
Published: September 2013

Deconvolution is a recent milestone in well test analysis which converts multirate pressure data into a single drawdown at constant rate. It yields a pressure derivative with a duration equal to the duration of the test, thus providing more pressure data to interpret than with conventional techniques; and gives access to the true radius of investigation of the test. In addition, the deconvolved derivative is free from distortions due to the pressure derivative calculation algorithm and from errors introduced by incomplete or truncated rate histories. Theoretically, deconvolution is only valid for linear systems. In practice, it is also used, with pseudo-pressures, for dry gas, and even for gas condensate and volatile oil below saturation pressure. As these systems are highly non-linear, there has been some concerns about the validity of such an approach.

This paper investigates the use of deconvolution for gas condensate and volatile oil below saturation pressure. Using compositional simulation, it applies deconvolution to different reservoir geometries using two-phase pseudo-pressures, which linearize the reservoir-fluid system by replacing the two-phase fluid below saturation pressure by a single fluid equivalent. Comparison with deconvolution using single-phase pseudo-pressure (for gas condensate) or pressure (for volatile oil) shows that the resulting deconvolved derivatives are similar, and in particular exhibit similar late time behaviours, thus justifying the simpler pseudo-pressure (resp., pressure) approach. Simulation results were verified with actual data from vertical and horizontal wells in a number of gas condensate and volatile oil reservoirs.
Investigation of Nanoparticle Adsorption during Transport in Porous Media
Authors: Zhang Tiantian , Murphy Michael , Yu Haiyang , G.Bagaria Hitesh , Yoon Ki Youl , Nielson Bethany M. , Bielawski Christopher W. , Johnston Keith P. , Huh Chun , Bryant Steven L.
Published: September 2013

Nanoparticles (D ∼ 5 to 50 nm) easily pass through typical pore throats in reservoirs, but physicochemical attraction between nanoparticles and pore walls may still lead to significant adsorption. We conducted an extensive series of nanoparticle transport experiments in core plugs and in columns packed with crushed sedimentary rock, systematically varying flow rate, type of nanoparticle, dispersion concentration, number and sizes of dispersion slugs, and column grain size. Effluent nanoparticle concentration histories were measured with fine resolution in time, enabling evaluation of nanoparticle adsorption in the columns during flow of dispersion and of postflushes. We also apply this analysis to transport experiments reported in the literature.

Our analysis indicates that nanoparticles undergo both reversible and irreversible adsorption. Effluent nanoparticle concentration reaches the injection concentration during slug injection, indicating the existence of an adsorption capacity. Experiments with a variety of nanoparticles and lithologies yield a wide range of adsorption capacities (from 10−7 to 10−2 g nanoparticle/g porous medium) and a wide range of proportions of reversible and irreversible adsorption. Reversible and irreversible adsorption sites are distinct and interact with nanoparticles independently of each other. The adsorption capacities are typically much less than monolayer coverage but are not an intrinsic property of the porous medium nor of the nanoparticle. Instead, they are influenced by operating conditions, i.e., increasing with larger injection concentration and smaller flow rate.
High Pressure Stimulation – Impact of Hydraulic Fracture Geometry to Unconventional Gas Appraisal and Development in Compressional Settings
Authors: Yuan Roger , Jin Liang , Zhu Changlong , Vitthal Sanjay , Xu Bin
Published: September 2013

For unconventional resources exploration and development, hydraulic fracture pattern, geometry and associated dimensions are critical elements in determining if the uneconomically low-permeability reservoirs can be effectively and efficiently stimulated. In principle, hydraulic fracture growth pattern is dominated by the state of stress in the subsurface, and commonly and optimally, hydraulic fractures are expected to grow vertically from deep wells and to have sufficient height growth to connect stacked hydrocarbon-bearing and horizontally more permeable reservoir packages while being contained to stay away from water-rich intervals. While the tectonic setting and in-situ stress conditions for vertical fracture development have been well studied, those for horizontal or complex fractures remain unclear or not well reported. In this paper, a case study is presented on the complex hydraulic fracture in a highly over-pressured and tectonically stressed tight gas field in the Sichuan Basin of southwest China.

During deep well hydraulic stimulation of the primary reservoirs of the Upper Triassic Xujiahe formation in the central western Sichuan Basin, difficulties are encountered in formation breakdown, injectivity establishment, proppant placement, pump equipment shut down, continuous high treating pressures, casing shear, and screen-out. These difficulties are preceded by larger-than-overburden breakdown pressures and ISIPs (Instantaneous Shut-In Pressure) during diagnostic pre-fracture injection tests, which imply that hydraulic fracture may have initiated and propagated horizontally. Different fracture monitoring techniques, however, have indicated that instead of getting purely horizontal fracture geometry, hydraulic fractures may have formed a complex network characteristic of T-shape or I-shape geometry. The main causes for such complex fracture geometry and limited fracture height are investigated and studied.

To quantitatively evaluate the fracturing performance and strategy, two classes of numerical hydraulic fracture models are undertaken. In addition to the LEFM (Linear Elastic Fracture Mechanics) based hydraulic fracture simulation, a fully-coupled finite-element based model is developed that takes into account a full suite of rock mechanical properties of sandstone and shale sequences and geological features that may limit or facilitate the fracture growth. The modeling results indicate that in addition to the typical stress control on the growth of fracture height, contrast in mechanical property and the presence of bed-parallel geological features may act as fracture baffles or barriers that prematurely arrest the vertical growth and facilitate development of horizontal fractures.
Deciding Whether to Fund Either CCS or CCUS Offshore Projects: Are We Comparing Apples and Pears in the North Sea?
Authors: Harrison Bob , Falcone Gioia
Published: September 2013

Recent years have seen significant funding competitions launched in Europe and in the UK that call for bidders to propose commercial demonstration projects which will bring innovation across the carbon capture and sequestration (CCS) technology chain to reduce energy system costs. The primary carbon dioxide (CO2) storage site candidates that are targeting funds are the saline aquifers and depleted oil and gas fields in the North Sea. At the time of writing, no outright winners have been announced.

These programs are open to CCS projects as well as carbon capture, utilization and storage (CCUS) projects. The former deals exclusively with greenhouse gas storage, but the latter differs by using the injected CO2 for enhanced oil recovery (EOR) before eventually being stored. Hence, there are considerable technical and commercial differences between CCS and CCUS projects, in much the same way as onshore projects face less challenges and constraints than if they were being implemented offshore.

The evaluation and selection of which offshore carbon storage projects should be funded is a tough exercise to undertake, but it becomes much more difficult if the competing projects under consideration are allowed to be CCS or CCUS, full chain or part chain, or a mixture of all of the aforementioned. Bias may arise via reliance on selection criterion such as volume of stored CO2 per unit of expenditure, which is likely to favor saline aquifer storage projects over other types, no matter how innovative or compelling they are.

The authors believe that selection committees in Brussels and London would greatly simplify their decision of which bid should be funded, and in what proportion, by separating competing projects into straightforward storage types and CO2-EOR types. Offshore experience of either project type is scarce and their relative merits are difficult to reconcile as the subsurface understanding, timeframe, economics, performance and goals of each project type are quite different.

The paper recognizes that CCS-type projects can be further subdivided into saline aquifers, with open and closed systems, and abandoned gas fields, as each have different storage limitations. Also, CCUS-type projects, which realistically only include abandoned oil fields, can be further subdivided to reflect the operational and commercial characteristics of different EOR schemes.

It is hoped that the discussion outlined in this paper will lead to easier and fairer screening criteria for offshore CCS and CCUS projects for use by governments, operators and investors alike.
Anisotropic Dispersion and Upscaling for Miscible Displacement
Authors: Adepoju Olaoluwa O. , Lake Larry W. , Johns Russel T.
Published: September 2013

Dispersion is the irreversible mixing that occurs during miscible displacements. Dispersion can reduce local displacement efficiency by lessening solvent peak concentration or increase volumetric sweep efficiency by spreading of the injected solvent to more of the reservoir. Dispersion is therefore an important parameter in predicting and simulating miscible displacements. The difficulty of simulating miscible displacement and understanding the effect of dispersion is also compounded by numerical dispersion, which increases the apparent dispersion in finite difference simulation models.

This paper presents an approach to estimate the total longitudinal and transverse dispersion in large-scale media using continuous solvent injection in a medium of finite thickness. The simulations are based on the experimental arrangement of Blackwell (1962) to estimate transverse dispersion, whose experimental consisted of co-injecting two miscible fluids into different sections of the medium at similar rates. Coupled with analytical solutions for two-dimensional convection dispersion equation for a continuously injected solvent we can determine longitudinal and transverse dispersivity simultaneously for the flow medium. In this manner we investigate the effects of stochastic permeability distributions and other scaling groups affecting first contact miscible simulations on dispersion.

Sensitivity analysis of dispersion in stochastic permeability fields confirms that both longitudinal and transverse dispersion are scale-dependent. Results also show that the effect of increasing autocorrelation of cell permeability in the longitudinal direction (parallel to flow) is to increase longitudinal dispersion, as solvent travels through more continuous layers, while reducing transverse dispersion. Increasing autocorrelation in the transverse direction is to reduce dispersion in both directions. This reduction is caused by equilibration of solvent concentrations in continuous sections of the reservoir resulting in reduced solute fingering and channeling.

Finally, we developed a simple procedure to use the estimated dispersivities to determine a-priori the maximum grid-block size that will maintain equivalent level of dispersion between fine-scale and upscaled coarse models. Large grid block sizes can be used for highly heterogeneous and layered reservoir models. Non-uniform coarsening (upscaling) methods were also recommended and validated for reservoir models with sets of sequential but different permeability distributions. The procedure was extended to multi-contact miscible simulations. The sweep and recovery from upscaled multi-contact miscible simulations were comparable to those of fine scale models.