bluuebunny/crossref_metadata_2025 huggingface dataset:
Injector-Well Completion Designs for Selectively Waterflooding Up to 18 Zones in a Multilayered Reservoir: Experiences in the Cerro Dragon Field
Authors: Massaglia E. , Baldassa D. , Ponce C. , Zalazar B.
Published: December 2007

The Cerro Dragon asset, located in the highly mature area of Golfo San Jorge Basin, Argentina, has around 30 producing structures; each one containing from 20 to 50 separate, highly heterogeneous, reservoir horizons, from 6 to 30 feet thick. From 1999 to 2005 proved reserves increased threefold and non proved reserves increased fourfold, moreover, oil production grew from 48,000 BOEPD to over 116,000 BOEPD, largely due to optimization and expansion of waterflood projects.

The aim of these projects was to increase the water injection rate from 248,000 BWPD to 714,000 BWPD along with the 1999 average of 5 reservoirs accessed per injector-well to an average of 12, with a maximum of 25, in 2005, keeping at the same time the highest possible control over the injected-water flow rate on each layer.

In an experimental process started in 2000, injector-well completions were designed and tested in several wells with different reservoir properties. The experience acquired with the analysis of these completions was used to improve them as well as to develop new ones. Today, this process continues, testing and enhancing new designs to fulfill the needs of the upcoming waterflooding projects.

This paper shows the experience acquired from 401 injector-well completions over the past 6 years, discuss the successes and problems encountered with each completion design under different reservoir conditions (i.e. differential pressures between layers). In addition, it contains information about the procedures and technology used to reduce the completion set up cost and to extend its useful life by solving leakage problems without replacing the completion installation.

The mayor achievement at this point of the process have been successfully running an injector-well completion of a total of 19 packers and 18 injector mandrels (with an average of 12 packers and 12 mandrels out of 48 completions ran on the first half of 2005).

The objective of this paper is to serve as a reference guide for injector-well completion designs in multilayered fields where a vertical expansion of the waterflooding projects is intended.
The Effect of Varicocele Repair on Experimental Varicocele‐Induced Testicular Germ Cell Apoptosis
Authors: Fazlioglu Adem , Yilmaz Inanc , Mete Özgür , Kurtulus Fatih , Parlakkilic Oguzhan , Güctas Özgür , Cek Mete
Published: December 2007

ABSTRACT: The purpose of this study was to evaluate the variance of apoptosis in rats in which experimental varicocele was induced and then treated by varicocelectomy. Forty adult male Wistar albino rats were used in this experimental study. Experimental varicocele was created in 30 rats. A total of 5 rats underwent a sham operation, and the remaining 5 rats were the control group. A total of 5 rats from the varicocele group were sacrificed on the 14th postoperative day, and 5 more were sacrificed on the 28th postoperative day to document the level of apoptosis due to varicocele. Varicocelectomy was performed on 20 rats with varicocele on the 14th postoperative day. These 20 rats were divided into 4 groups to evaluate the level of apoptosis in their testis after varicocelectomy. They were sacrificed on days 7, 14, 21, and 28 after varicocelectomy. The testes were fixated by perfusion with 10% formaldehyde and then placed in paraffin blocks. From each testis, 2 samples were stained with hematoxylin and eosin, and 2 samples were stained using the TUNEL method. In each specimen, apoptotic germ cells stained by TUNEL were counted in the cross section of 100 seminiferous tubules. The apoptotic index was defined by calculating the number of apoptotic cells per seminiferous tubule. Apoptotic index = total apoptotic germ cell count/100. In the adult rats on which experimental varicocele was performed, both in the second and fourth week, apoptosis in both left and right testes were significantly higher compared with the control group (with varicocele day 14: 0.25–0.26, with varicocele day 28: 0.28–0.32, control: 0.11–0.13). After varicocelectomy on the 7th and 14th days, the slight increase in the level of apoptosis continued (day 7 left testis: 0.30, day 7 right testis: 0.28; day 14 left testis: 0.25, day 14 right testis: 0.31). After varicocelectomy, apoptosis decreased significantly on day 21 (left testis: 0.16, right testis: 0,22), and on day 28 it was almost equal to the level of the control group (left testis: 0.14, right testis: 0.16). After the creation of unilateral varicocele, the level of apoptosis increased in both the left and right testes. Apoptosis in both testes decreased after surgical treatment.
Correlation Between CFTR Gene Mutations in Iranian Men With Congenital Absence of the Vas Deferens and Anatomical Genital Phenotype
Authors: Radpour Ramin , Gourabi Hamid , Gilani Mohamad Ali Sadighi , Dizaj Ahmad Vosough
Published: December 2007

ABSTRACT: Congenital bilateral absence of the vas deferens (CBAVD) and congenital unilateral absence of the vas deferens (CUAVD) are 2 causes of male sterility; these phenotypes are found in 1%–2% of men investigated for infertility and approximately 10% of men with azoospermia. To study the correlation between genital phenotype and cystic fibrosis genotype in men lacking at least 1 vas deferens, we evaluated the role of different CFTR gene mutations in the morphologic genital phenotype of 119 infertile men with bilateral or unilateral absence of the vas deferens (112 CBAVD and 7 CUAVD patients). Renal, scrotal, and transrectal ultrasonography were systematically performed. CFTR mutations and (TG)m(T)n polymorphism were analyzed, and epididymal and seminal vesicular abnormalities and testicular volume were compared among men with 2, 1, or no CFTR gene mutation, with or without the 5T allele. Our results showed that patients with CBAVD and renal agenesis have the same reproductive tract abnormalities as those with CUAVD, and reproductive tract abnormalities were independent of the subtypes of CFTR genotype in patients with absence of the vas deferens and CFTR gene mutations. Seminal vesicles did not differ between patients with or without CFTR gene mutation, but epididymal abnormalities were more frequent in CBAVD men without the mutation. Low testicular volume was observed in CBAVD men without the CFTR and IVS8‐5T mutations, so we can hypothesize that a testicular factor (genetic or environmental) rather than CFTR gene mutations plays a role in determining the phenotype. Further studies using common diagnostic criteria are required to confirm our observations.
Proinflammatory Cytokines as an Intermediate Factor Enhancing Lipid Sperm Membrane Peroxidation in In Vitro Conditions
Authors: Fraczek Monika , Sanocka Dorota , Kamieniczna Marzena , Kurpisz Maciej
Published: December 2007

ABSTRACT: We have examined the effect of white blood cells (WBCs), various proinflammatory cytokines, or a combination of the two on the peroxidation of human sperm membrane lipids in in vitro conditions. Six recombinant cytokines, such as interleukin‐1β (IL‐1β), IL‐6, IL‐8, IL‐12, IL‐18, and tumor necrosis factor alpha (TNF‐α), used singly or in combinations, were analyzed. WBCs were isolated from the whole heparinized blood using a density gradient technique (Histopaque 1.077). Spermatozoa were isolated from semen samples with normal sperm parameters by both the swim‐up technique (swim‐up fraction) and by a discontinuous Percoll gradient centrifugation (90% and 47% Percoll fractions). Peroxidative damage to sperm membrane lipids was assessed by determining the concentration of malondialdehyde (MDA) in lysates of spermatozoa using high‐performance liquid chromatography (HPLC). There were no statistically significant differences in MDA concentrations between sperm fractions incubated with cytokines and respective controls (spermatozoa alone). In spermatozoa isolated by the swim‐up technique, the MDA level was significantly higher only after incubation with IL‐6 and IL‐8 plus WBCs when compared to sperm incubated with leukocytes alone (0.62 ± 0.21 μmol/L and 0.42 ± 0.22 μmol/L, respectively; P < .05). In spermatozoa recovered from the 47% Percoll, only a combination of IL‐12 and IL‐18 used together with WBCs was linked with a significant increase in MDA concentration (from 0.41 ± 0.13 μmol/L to 0.65 ± 0.19 μmol/L; P < .05). The results obtained suggest that cytokines produced during the inflammatory process intensify the level of oxidative stress caused by leukocytes, which may have serious consequences for sperm membrane integrity.
Molecular Pharmacotherapeutic Targeting of PDE5 for Preservation of Penile Health
Authors: Burnett Arthur L.
Published: December 2007

ABSTRACT: The molecular science of erection physiology has established that phosphodiesterase 5 (PDE5) serves an important biological role in the penis. Current research in the field has revealed this molecular effector to be relevant for penile erection, controlling the erectile response by degrading the second messenger product of the erection mediatory nitric oxide (NO) signaling pathway, 3′, 5′‐cyclic guanosine monophosphate. Accordingly, PDE5 has been targeted for sexual medicine purposes, and orally administered PDE5 inhibitors such as sildenafil, tadalafil, and vardenafil comprise a foremost intervention for erectile dysfunction (ED). New investigation of PDE5 regulation in the penis has suggested alternative roles for the enzyme and new therapeutic opportunities involving its molecular interactions. In particular, PDE5 function is altered under derangements of androgen deficiency, decreased NO bioactivity, and oxidative stress‐associated inflammatory changes, thus contributing to an assortment of erectile disorders including hypogonadism‐associated ED, recurrent ischemic priapism, penile vasculopathy, and penile fibrosis. This review provides a critical examination of the multifaceted role of the PDE5 regulatory system in the penis and its relevance for applying existing and emerging therapeutic strategies for erectile disorders.
Implicature, Pragmatics, and Documentation: A Comparative Study
Authors: Wright David
Published: December 2007

This study investigates the link between the linguistic principles of implicature and pragmatics and software documentation. When implicatures are created in conversation or text, the listener or reader is required to fill in missing information not overtly stated. This information is usually filled in on the basis of previous knowledge or context. Pragmatics, the study of language use in context, is concerned with the situational aspects of language use that, among other things, directly affect implicatures required of the reader. I investigate how two manuals for the same software product can be analyzed on the basis of implicature and pragmatics. One is an original copy of the documentation that came with the product, the other an after-market manual. Results show that the aftermarket manual requires far fewer implicatures of the reader and does a better job of providing pragmatically helpful information for the user.
Scale and Transaction Costs in the U.S. Biopower Industry
Authors: Altman Ira J , Klein Peter G. , Johnson Thomas G.
Published: December 2007

With increasing interest in renewable energy from agriculture, including biopower and cellulose ethanol, there is a need for better understanding of the economic organization of this emerging industry. Study of the organization of the biopower industry represents an under-researched area and a new application of transaction cost theory to an emerging industry.Refinement of the theory can also result from challenging applications. This article provides an application of transaction cost economics to the existing United States biopower industry while challenging the empirical convention of excluding production cost variables from transaction cost analysis. Utilizing survey data from 53 biopower generators we study the relationship between physical asset specificity, site specificity, and scale in explaining firms' decisions to procure inputs internally, externally, or to use both methods. Consistent with transaction cost theory, both site specificity and scale are good predictors of organizational form. Given this evidence, this article reconsiders the impact of scale and transaction costs on the choice of organizational from.
Estimating the Welfare Effects of U.S. Distortions in the Ethanol Market Using a Partial Equilibrium Trade Model
Authors: Martinez-Gonzalez Ariadna , Sheldon Ian M , Thompson Stanley
Published: December 2007

In this paper the impact of distortions on U.S. imports of ethanol from Brazil are calculated. This is achieved by using two-stage least squares to estimate a partial equilibrium trade model based on annual data from 1975 to 2006. From this the derived export supply and import demand elasticities are used to derive "back-of-the-envelope" measures of the static and cumulative deadweight losses, assuming the distortions are not eliminated. The results presented support the hypothesis that the U.S. and Brazil would reap gains from trade if distortions in the U.S. ethanol market were eliminated.
Estimation of Expression Levels in Spotted Microarrays with Saturated Pixels
Authors: Glasbey Chris A , Forster Thorsten , Ghazal Peter
Published: December 2007

Digital images obtained by the laser scanning of spotted microarrays often include saturated pixel values. These arise when the scan settings are sufficiently high and some pixels exceed the limit L=65535 and are instead set to L. Failure to adjust for this censoring leads to biased estimates of gene expression levels. To impute censored values, we propose a linear model based on the principal components of uncensored spots on the same array. This is computationally fast, flexible to adapt to distinctive spot shapes and profiles on different arrays, and is shown to be more effective than the polynomial-hyperbolic model in correcting for the bias. The application to biological data demonstrates the potential for enhancing the dynamic range of detection. Fortran90 subroutines implementing these methods are available at http://www.bioss.ac.uk/~chris.
Forced Air Precooling Studies of Perishable Food Products
Authors: Albayati Omer Adil Zainal , Kumar Ravi , Chauhan Gopal
Published: December 2007

Food products of perishable nature are needed to be preserved from spoiling using the precooling technique. Precooling is the process of cooling fruits and vegetables as soon as possible after the harvest and prior to the transportation over long distances to a cold storage warehouse and marketing. Therefore, an experimental investigation has been carried out to study the temperature variation of different food products viz. apple, papaya and grape during the precooling process. Forced air cooling of food products was done by placing the particular food item inside a 4 m long rectangular air duct of 300 mm x 300 mm section. The temperature of cold air was in a range of 4-5 oC and the air velocity varied from 1.6 m/s to 4.1 m/s. The temperature of food product was measured at different radial locations inside the product. The effect of air velocity on the temperature profile of food product was observed and it has been found that the proper choice of cold air velocity can reduce the cooling time of certain food product up to 33 percent, thus, resulting in the saving of energy.
Determining the Optimized Controller Parameters Using a Hybrid GA-SQP Technique
Authors: Mansoornejad Behrang , Mostoufi Navid , Jalali-Farahani Farhang
Published: December 2007

Dynamic simulation and optimization of a hydrogenation reactor system were developed and investigated in the present work. The process mainly consists of three adiabatic fixed bed hydrogenation reactors in series in addition to one heater before the first reactor and three coolers after each reactor for interstage cooling. The feed flow rate to the unit, the feed temperature or the carbon monoxide content of the feed may change and cause variations of the outlet temperature of reactors. Therefore, it is essential to control the inlet temperature of each reactor. There is a temperature controller before each reactor and also one after the third reactor. The tuning parameters of the controllers were optimized in three different cases, taking into account the process constraints. In each case, a special disturbance was forced to the process. Because of catalyst deactivation, the inlet temperature of reactors must be increased during the running period in order to have the desired conversion. Therefore, the optimal inlet temperature profile was determined based on SOR, MOR and EOR data. Optimization of the process was done by the use of a hybrid GA-SQP method. The new hybrid method was developed to overcome the difficulties of both methods. The genetic algorithm (GA) which is a stochastic method, is relatively slow, but is not sensitive to the initial point. In contrast, sequential quadratic programming (SQP) method is a deterministic method which is fast, but very sensitive to the initial point and gets trapped in local optima. In the newly developed hybrid method, the SQP method speeds the solving procedure, while the GA enables the algorithm to escape from local optima. An industrial acetylene hydrogenation system was used to provide the necessary data to adjust kinetics and to validate the approach.
A short‐term operational planning model for natural gas production systems
Authors: Selot Ajay , Kuok Loi Kwong , Robinson Mark , Mason Thomas L. , Barton Paul I.
Published: December 2007

A short‐term operational planning model for natural gas production systems can help identify a consistent operational policy that satisfies contractual rules and customer specifications. Formulating and solving such a model poses challenges due to nonlinear pressure‐flowrate relations, a multicommodity network and complex production‐sharing contracts (PSC). A production allocation model is presented that can be viewed as a contractual model superimposed on an infrastructure model. The infrastructure model incorporates nonlinear pressure‐flowrate relationships for wells and pipelines, multiple qualities of gas in the trunkline network and models of facilities. The contractual model is a mathematical representation of the PSC and associated operational rules. The model features are inspired by the Sarawak Gas Production System (SGPS) in East Malaysia. A case study similar to the Sarawak Gas Production System (SGPS) is presented. The final formulation is a nonconvex mixed‐integer nonlinear program and is solved with GAMS/BARON to global optimality. A hierarchical multiobjective operational study is also presented. © 2007 American Institute of Chemical Engineers AIChE J, 2008
Wisecrackers: A theory‐grounded investigation of phishing and pretext social engineering threats to information security
Authors: Workman Michael
Published: December 2007

The collection and dissemination of information about people by businesses and governments is ubiquitous. One of the main threats to people's privacy comes from human carelessness with this information, yet little empirical research has studied behaviors associated with information carelessness and the ways that people exploit this vulnerability. The studies that have investigated this im‐portant question have not been grounded in theory. In particular, the extant literature reveals little about social engineering threats and the reasons why people may or may not fall victim. Synthesizing theory from the marketing literature to explain consumer behavior, an empirical field study was conducted to see if factors that account for successful marketing campaigns may also account for successful social engineering attacks.
Pharmacokinetics of riluzole: evidence for glucuronidation as a major metabolic pathway not associated with UGT1A1 genotype
Authors: van Kan H. J. M. , van den Berg L. H. , Groeneveld G. J. , van der Straaten R. J. H. M. , van Vught P. W. J. , Lie‐A‐Huen L. , Guchelaar H.‐J.
Published: December 2007

Pharmacokinetic studies of riluzole show a large inter‐individual variability of the drug's clearance and serum concentrations. Optimizing the individual dosage of riluzole may have the potential to improve the effect of riluzole treatment on survival of patients with amyotrophic lateral sclerosis (ALS).

Limited data are available on thein vivometabolic elimination of riluzole. Fromin vitroexperiments, CYP1A2 seems to be mainly involved in riluzole clearance. However,in vitrostudies suggest that formation of riluzole‐glucuronide plays a role and may determine the drug's pharmacokinetic variability in patients to some extent.

In the current study the formation of riluzole‐glucuronide was examined in amyotrophic lateral sclerosis (ALS) patients. It also aimed at relating glucuronidation of riluzole to differential UGT1A1*28 genotypes.

The formation of riluzole‐glucuronide was confirmed in serum from a group of 14 ALS patients taking riluzole. Riluzole‐glucuronide concentrations were positively associated with those of riluzole. In a separate group of 131 ALS patients taking riluzole, the UGT1A1*28 genotype was not associated with trough or peak serum concentrations of riluzole.

This study provides evidence that thein vivometabolic elimination of riluzole in ALS patients involves glucuronidation. The results do not indicate that glucuronidation of riluzole highly contributes to the drug's inter‐individual pharmacokinetic variability. Copyright © 2007 John Wiley & Sons, Ltd.
Interpretation of skeletal variations for human risk assessment: delayed ossification and wavy ribs
Authors: Carney Edward W. , Kimmel Carole A.
Published: December 2007

Delayed (or incomplete) ossification of developing fetal bones and wavy ribs are some of the most common skeletal variations encountered in regulatory guideline developmental toxicity studies. Although they tend to be regarded as minor effects, they can be quite sensitive and consequently may influence the study lowest‐observed‐adverse‐effect levels (LOAELs), and thus, impact classification, labeling, and risk assessment. In this study, we review the underlying mechanisms of these skeletal variations, evaluate different scenarios in which they have been observed, offer guidance for their interpretation, and comment on their use for risk assessment. Both minor delays in ossification and wavy ribs seem to be readily repairable via postnatal skeletal remodeling, are not mechanistically linked to malformation, and often are seen in the presence of maternal or fetal toxicity. As such, these minor variations would not generally be considered adverse in and of themselves but should be interpreted in the context of other maternal and fetal findings, information available on normal skeletogenesis patterns, mode of action of the test agent, and historical control incidence using a weight of evidence approach. Birth Defects Res 80:473–496, 2007. © 2007 Wiley‐Liss, Inc.
Multi‐way models for sensory profiling data
Authors: Bro Rasmus , Qannari El Mostafa , Kiers Henk A. L. , Næs Tormod , Frøst Michael Bom
Published: December 2007

One of the problems in analyzing sensory profiling data is to handle the systematic individual differences in the assessments from different panelists. It is unavoidable that different persons have, at least to a certain degree, different perceptions of the samples as well as a different understanding of the attributes or of the scales used for quantifying the assessments. Hence, any model attempting to describe sensory profiling data needs to deal with individual differences; either implicitly or explicitly. In this paper, a unifying family of models is proposed based on (i) the assumption that latent variables are appropriate for sensory data, and (ii) that individual differences occur. Based on how individual differences occur, various mathematical models can be constructed, all aiming at modeling simultaneously the sample‐specific variation and the panelist‐specific variation. The model family includes Principal Component Analysis (PCA) and PARAllel FACtor analysis (PARAFAC). The paper can be viewed as extending the latent variable approach commonly based on PCA to multi‐way models that specifically take certain panelist‐variations into account. The proposed model family is focused on analyzing data from quantitative descriptive analysis with fixed vocabulary, but it also provides a foundation upon which comparisons, extensions and further developments can be made. An example is given which shows that even for well‐working data, models handling individual differences can shed important light on differences between the quality of the data from individual panelists. Copyright © 2007 John Wiley & Sons, Ltd.
ST‐PLS: a multi‐directional nearest shrunken centroid type classifier via PLS
Authors: Sæbø Solve , Almøy Trygve , Aarøe Jørgen , Aastveit Are H.
Published: December 2007

The nearest shrunken centroid (NSC) Classifier is successfully applied for class prediction in a wide range of studies based on microarray data. The contribution from seemingly irrelevant variables to the classifier is minimized by the so‐called soft‐thresholding property of the approach. In this paper, we first show that for the two‐class prediction problem, the NSC Classifier is similar to a one‐component discriminant partial least squares (PLS) model with soft‐shrinkage of the loading weights. Then we introduce the soft‐threshold‐PLS (ST‐PLS) as a general discriminant‐PLS model with soft‐thresholding of the loading weights of multiple latent components. This method is especially suited for classification and variable selection when the number of variables is large compared to the number of samples, which is typical for gene expression data. A characteristic feature of ST‐PLS is the ability to identify important variables in multiple directions in the variable space. Both the ST‐PLS and the NSC classifiers are applied to four real data sets. The results indicate that ST‐PLS performs better than the shrunken centroid approach if there are several directions in the variable space which are important for classification, and there are strong dependencies between subsets of variables. Copyright © 2007 John Wiley & Sons, Ltd.
Repeated stress alters dendritic spine morphology in the rat medial prefrontal cortex
Authors: Radley Jason J. , Rocher Anne B. , Rodriguez Alfredo , Ehlenberger Douglas B. , Dammann Mark , McEwen Bruce S. , Morrison John H. , Wearne Susan L. , Hof Patrick R.
Published: December 2007

Anatomical alterations in the medial prefrontal cortex (mPFC) are associated with hypothalamopituitary adrenal (HPA) axis dysregulation, altered stress hormone levels, and psychiatric symptoms of stress‐related mental illnesses. Functional imaging studies reveal impairment and shrinkage of the mPFC in such conditions, and these findings are paralleled by experimental studies showing dendritic retraction and spine loss following repeated stress in rodents. Here we extend this characterization to how repeated stress affects dendritic spine morphology in mPFC through the utilization of an automated approach that rapidly digitizes, reconstructs three dimensionally, and calculates geometric features of neurons. Rats were perfused after being subjected to 3 weeks of daily restraint stress (6 hours/day), and intracellular injections of Lucifer Yellow were made in layer II/III pyramidal neurons in the dorsal mPFC. To reveal spines in all angles of orientation, deconvolved high‐resolution confocal laser scanning microscopy image stacks of dendritic segments were reconstructed and analyzed for spine volume, surface area, and length using a Rayburst‐based automated approach (8,091 and 8,987 spines for control and stress, respectively). We found that repeated stress results in an overall decrease in mean dendritic spine volume and surface area, which was most pronounced in the distal portion of apical dendritic fields. Moreover, we observed an overall shift in the population of spines, manifested by a reduction in large spines and an increase in small spines. These results suggest a failure of spines to mature and stabilize following repeated stress and are likely to have major repercussions on function, receptor expression, and synaptic efficacy. J. Comp. Neurol. 507:1141–1150, 2008. © 2007 Wiley‐Liss, Inc.
Adaptive finite element approximation of multiphysics problems
Authors: Larson Mats G. , Bengzon Fredrik
Published: December 2007

Simulation of multiphysics problems is a common task in applied research and industry. Often a multiphysics solver is built by connecting several single‐physics solvers into a network. In this paper, we develop a basic adaptive methodology for such multiphysics solvers. The adaptive methodology is based on a posteriori error estimates that capture the influence of the discretization errors in the different solvers on a given functional output. These estimates are derived using duality‐based techniques. Copyright © 2007 John Wiley & Sons, Ltd.
Cytogenetic analysis of 101 skull base tumors
Authors: Gil Ziv , Orr‐Urtreger Avi , Voskoboinik Nadia , Trejo‐Leider Leonor , Shomrat Ruth , Fliss Dan M.
Published: December 2007

Background.

Skull base tumors are rare neoplasms and the cytogenetic data on these tumors are limited. The authors cytogenetically analyzed a large series of tumors and compared the findings with patients' pathologic data.

Methods.

The karyotypes of pathologically confirmed samples of 101 patients, who were operated for oncological extirpation of tumors, were analyzed using G‐banding and spectral‐karyotyping techniques.

Results.

Of the 67 malignant tumors, 32 (48%) had chromosomal aberrations, some with complex numerical and structural chromosomal anomalies. Recurrent chromosomal breakpoints were identified in squamous cell carcinomas, adenoid cystic carcinomas (ACCs), sinonasal undifferentiated carcinomas, chordomas, and sarcomas. Specific breakpoints established the diagnosis of various soft tissue sarcomas. Novel chromosomal aberrations were found in various other malignant and benign tumors.

Conclusion.

This study highlights the value of cytogenetic analysis for diagnosis of skull base tumors. The data add further information on the biological behavior of these rare neoplasms. © 2007 Wiley Periodicals, Inc. Head Neck, 2008
Activation of peroxisome proliferator-activated receptor-α inhibits the injurious effects of adiponectin in rat steatotic liver undergoing ischemia–reperfusion
Authors: Massip-Salcedo Marta , Zaouali Amine M. , Padrissa-Altés Susagna , Casillas-Ramirez Arani , Rodés Joan , Roselló-Catafau Joan , Peralta Carmen
Published: December 2007

Hepatic steatosis is a major risk factor in ischemia–reperfusion (I/R). Adiponectin acts as an antiobesity and anti-inflammatory hormone. Adiponectin activates peroxisome proliferator-activated receptor-α (PPAR-α), a transcription factor that regulates inflammation in liver disease. Ischemic preconditioning (PC) based on brief periods of I/R protects steatotic livers against subsequent sustained I/R injury, but just how this is achieved is poorly understood. This study explains the role of PPAR-α and adiponectin in the vulnerability shown by steatotic livers to I/R and the benefits of PC in this situation. PPAR-α and adiponectin levels in nonsteatotic livers undergoing I/R were similar to those found in the sham group. However, reduced PPAR-α and increased adiponectin levels, particularly the high molecular weight isoform, were observed in steatotic livers as a consequence of I/R. Our results suggest that mitogen-activated protein kinases (MAPKs) may be positive regulators of adiponectin accumulation in steatotic livers. The addition of adiponectin small interfering RNA (siRNA) before I/R protected steatotic livers against oxidative stress and hepatic injury. The induction of PC before I/R increased PPAR-α and reduced adiponectin levels in steatotic livers. PC, which increased PPAR-α, as well as PPAR-α agonist pretreatment reduced MAPK expression, adiponectin, oxidative stress, and hepatic injury that follows I/R. In addition, the administration of a PPAR-α antagonist in preconditioned steatotic livers eliminated the beneficial effects of PC on MAPKs, adiponectin, oxidative stress, and hepatic injury.

Conclusion

: Steatotic livers are more predisposed to down-regulate PPAR-α and overexpress adiponectin when subjected to I/R. PPAR-α agonists and adiponectin siRNA are promising candidates to protect steatotic livers. PPAR-α agonists as well as PC, through PPAR-α, inhibited MAPK expression following I/R. This in turn inhibited adiponectin accumulation in steatotic livers and adiponectin-worsening effects on oxidative stress and hepatic injury. (Hepatology 2007.)
Determinants of public satisfaction with the National Health Insurance in South Korea
Authors: Lee Sang‐Yi , Suh Nam Kyu , Song Jung‐Kook
Published: December 2007

To explore the determinants of public satisfaction with the National Health Insurance, this study re‐analyzed the 2004 public satisfaction survey with the Korean National Health Insurance (KNHI) conducted by Korean National Health Insurance Corporation (KNHIC). One thousand samples were selected with probability proportional to population size (by region/sex/age). The data collected by home‐visit interview were transformed into the final data set by matching them to the insured's benefit database and the qualification database. The results showed that metropolitan residence, insured type, relationship between respondent and householder, subjective health status, benefit–cost ratio, and attitudes toward KNHI were direct determinants of satisfaction with KNHI. In addition, various demographic and socioeconomic variables and the health status of the respondent's family indirectly influenced satisfaction with KNHI. Among these variables, the attitude toward KNHI was the most vital factor to determine public satisfaction. The study results show that equity in monthly contributions and an enhanced quantity and quality of medical services are required to improve public satisfaction with KNHI. Furthermore, it is important to improve the public perception of social values and solidarity for increased public satisfaction with KNHI. Copyright © 2007 John Wiley & Sons, Ltd.
Quantifying the supply‐side benefits from forward contracting in wholesale electricity markets
Authors: Wolak Frank A.
Published: December 2007

The assumption of expected profit‐maximizing bidding behavior in a multi‐unit, multi‐period auction with step‐function supply curves is used to estimate cost functions for electricity generation units and derive tests of expected profit‐maximizing behavior. Applying these techniques to data from the National Electricity Market in Australia reveals statistically significant evidence of output‐dependent marginal costs within and across half‐hours of the day, but no evidence against the hypothesis of expected profit‐maximizing behavior. These cost function estimates quantify the economic significance of output‐varying costs and how forward financial contract obligations impact the amount of these costs the generation unit owner incurs. This supplier's existing obligations imply average daily production costs that are 8% lower than the profit‐maximizing pattern of output with no forward contract obligations. Copyright © 2007 John Wiley & Sons, Ltd.
Finite sample inference methods for dynamic energy demand models
Authors: Bernard Jean‐Thomas , Idoudi Nadhem , Khalaf Lynda , Yélou Clément
Published: December 2007

This paper considers finite sample motivated inference methods in dynamic energy demand models, in which case commonly used econometric methods remain asymptotic. We focus on structural stability, and on exact confidence set estimation of elasticities. We account for intractable and nuisance parameter dependant distributions through Monte Carlo test procedures. For long‐run elasticities which depend on parameter ratios, we assess available asymptotic and exact methods with Fieller based alternatives. Fieller based and exact methods invert approximate and exact relevant test criteria (respectively) and may lead to unbounded set estimates. Our empirical results underscore the importance of using identification‐robust inference methods. Copyright © 2007 John Wiley & Sons, Ltd.
Estimating market power in a two‐sided market: The case of newspapers
Authors: Argentesi Elena , Filistrucchi Lapo
Published: December 2007

The newspaper industry is a two‐sided market: the readers market and the advertising market are closely linked by inter‐market network externalities. We estimate market power in the Italian newspaper industry by building a structural model which encompasses a demand estimation for differentiated products on both sides of the market and where profit maximization by the publishing firms takes into account the interaction between them. The question that we address is whether the observed price pattern is consistent with profit‐maximizing behaviour by competing firms or is instead driven by some form of (tacit or explicit) coordinated practice. Copyright © 2007 John Wiley & Sons, Ltd.
Bone vascular supply in monitor lizards (Squamata: Varanidae): Influence of size, growth, and phylogeny
Authors: de Buffrénil Vivian , Houssaye Alexandra , Böhme Wolfgang
Published: December 2007

Bone vascular canals occur irregularly in tetrapods; however, the reason why a species has or lacks bone canals remains poorly understood. Basically, this feature could depend on phylogenetic history, or result from diverse causes, especially cortical accretion rate. The Varanidae, a monophyletic clade that includes species with impressive size differences but similar morphologies, is an excellent model for this question. Cortical vascularization was studied in 20 monitor species, on three bones (femur, fibula, and tibia) that differ in their shaft diameters, and in the absolute growth speed of their diaphyseal cortices. In all species smaller than 398 mm SVL (133–397 mm in sample), bone cortices lack vascular canals, whereas all larger species (460–1,170 mm in sample) display canals. The size 398–460 mm SVL is thus a threshold for the appearance of the canals. The distribution of vascular and avascular bone tissues among species does not precisely reflect phylogenetic relationships. When present, vascular canals always occur in the femur and tibia, but are less frequent, sparser, and thinner in the fibula. Vascular density increases linearly with specific size but decreases exponentially during individual growth. In most species, canal orientation varies between individuals and is diverse in a single section. No clear relationship exists between canal orientation and vascular density. These results suggest that: a) the occurrence and density of bone vascular canals are basically dependant on specific size, not phylogenetic relationships; b) vascular density reflects the absolute growth rates of bone cortices; c) the orientation of vascular canals is a variable feature independent of phylogeny or growth rate. J. Morphol., 2008. © 2007 Wiley‐Liss, Inc.
Functional anatomy of the limbs of erethizontidae (Rodentia, Caviomorpha): Indicators of locomotor behavior in Miocene porcupines
Authors: Candela Adriana M. , Picasso Mariana B.J.
Published: December 2007

Functional analysis of the limb bones of the erethizontid Steiromys duplicatus, one of the most abundant Miocene porcupines from Patagonia, provides evidence to infer their locomotor behavior. Remains of the giant Neosteiromys pattoni (Late Miocene of Northeast Argentina) are also analyzed. Osteological and myological features of extant porcupines were evaluated and used as a model to interpret the functional significance of Miocene species' limbs. Several features in erethizontids are compatible with the ability to climb: the low humeral tuberosities indicate a mobile gleno‐humeral joint; the prominent and distally extended deltopectoral crest indicates a powerful pectoral muscle, which is particularly active when climbing; the humero‐ulnar and humero‐radial joints are indicative of pronation‐supination movements; the well‐developed lateral epicondylar ridge and the medially protruding entepicondyle are in agreement with an important development of the brachioradialis, supinator, flexor digitorum profundus, and pronator teres muscles, acting in climbing and grasping functions; the mechanical advantage of the biceps brachii would be emphasized because of its distal attachment on the bicipital tuberosity. As with extant porcupines, in Miocene species, the large femoral head would have permitted a broad range of abduction of the femur, and the medially protruding lesser trochanter would have emphasized the abduction and outward rotation of the femur by the action of the ilio‐psoas complex. In S. duplicatus, the shape of the hip, knee, and cruro‐astragalar, calcaneo‐astragalar, and astragalo‐navicular joints would have allowed lateral and rotational movements, although probably to a lesser degree than in extant porcupines. Foot features of S. duplicatus (e.g., great medial sesamoid bone, medial astragalar head, complete hallux) indicate that this species would have had grasping ability, but would not have achieved the high degree of specialization of Coendou. Steiromys duplicatus would have been a semiarboreal dweller, resembling Erethizon dorsatum. J. Morphol., 2008. © 2007 Wiley‐Liss, Inc.
Double common bile duct: Curved‐planar reformatted computed tomography (CT) and gadobenate dimeglumine–enhanced MR cholangiography
Authors: Park Mi‐Suk , Kim Byung Chang , Kim Tae il , Kim Myeong‐Jin , Kim Ki Whang
Published: December 2007

We present the case of a 61‐year‐old female with double common bile duct (CBD) with an opening into the lesser curvature of the stomach. We discuss the role of curved‐planar reformatted computed tomography (CT) and gadobenate dimeglumine (Gd‐BOPTA)–enhanced T1‐weighted MRI in confirming the diagnosis of this uncommon disease. J. Magn. Reson. Imaging 2008;29:209–211. © 2007 Wiley‐Liss, Inc.
Anger, hostility, and aggression among Iraq and Afghanistan war veterans reporting PTSD and subthreshold PTSD
Authors: Jakupcak Matthew , Conybeare Daniel , Phelps Lori , Hunt Stephen , Holmes Hollie A. , Felker Bradford , Klevens Michele , McFall Miles E.
Published: December 2007

Iraq and Afghanistan War veterans were grouped by level of posttraumatic stress disorder (PTSD) symptomatology and compared on self‐report measures of trait anger, hostility, and aggression. Veterans who screened positive for PTSD reported significantly greater anger and hostility than those in the subthreshold‐PTSD and non‐PTSD groups. Veterans in the subthreshold‐PTSD group reported significantly greater anger and hostility than those in the non‐PTSD group. The PTSD and subthreshold‐PTSD groups did not differ with respect to aggression, though both groups were significantly more likely to have endorsed aggression than the non‐PTSD group. These findings suggest that providers should screen for anger and aggression among Iraq and Afghanistan War veterans who exhibit symptoms of PTSD and incorporate relevant anger treatments into early intervention strategies.
Pharmacotherapy to prevent PTSD: Results from a randomized controlled proof‐of‐concept trial in physically injured patients
Authors: Stein Murray B. , Kerridge Carol , Dimsdale Joel E. , Hoyt David B.
Published: December 2007

Acute physical injury is frequently associated with mental health sequelae, which then accentuate disability and worsen functional outcomes. A pharmacological prevention approach to this problem has been proposed. This proof‐of‐concept study was a double‐blind, randomized controlled trial of 14 days of the beta‐blocker propranolol (n = 17), the anxiolytic anticonvulsant gabapentin (n = 14), or placebo (n = 17), administered within 48 hours of injury to patients admitted to a surgical trauma center. Of 569 accessible, potentially eligible subjects, 48 (8%) participated. Outcomes assessments were conducted at 1, 4, and 8 months postinjury. Although well tolerated, neither study drug showed a significant benefit over placebo on depressive or posttraumatic stress symptoms. Implications are discussed for future pharmacological prevention studies in survivors of acute traumatic injury.
The role of panic attacks in acute stress disorder in children
Authors: Sinclair Emma , Salmon Karen , Bryant Richard A.
Published: December 2007

This study examined the role of peritraumatic panic symptoms during trauma in childhood acute stress. Children (N = 60) who had suffered traumatic injury were administered the Child Acute Stress Reaction Questionnaire, the Child Depression Inventory, and the Physical Reactions Scale to index panic attacks that occurred during the trauma. Panic attacks were experienced during their trauma by 100% of participants with acute stress reactions and 24% of participants without stress reactions. Panic attacks during trauma accounted for 28% of the variance of acute stress reactions, with an additional variance accounted for by age, time since the accident, and dysphoria. These findings are discussed in terms of fear conditioning models of posttraumatic stress.
Trauma coping strategies and psychological distress: A meta‐analysis
Authors: Littleton Heather , Horsley Samantha , John Siji , Nelson David V.
Published: December 2007

The identification of adaptive and maladaptive coping strategies following traumatic events has been the subject of much scientific inquiry. The current study sought through meta‐analysis to evaluate the relationship between the use of approach and avoidance strategies (both problem‐focused and emotion/cognitive focused) following trauma and psychological distress. Thirty‐nine studies of coping following two types of traumatic events (interpersonal violence and severe injury) were retained in the meta‐analysis. There was a consistent association between avoidance coping and distress, overall r = .37, but no association between approach coping and distress, overall r = −.03, but some important moderators existed. Implications of the results for future research regarding coping and trauma recovery are discussed.
Efficient propagation of single cells accutase‐dissociated human embryonic stem cells
Authors: Bajpai Ruchi , Lesperance Jacqueline , Kim Min , Terskikh Alexey V.
Published: December 2007

Human embryonic stem cells (hESCs) hold great promise for cell‐based therapies and drug screening applications. However, growing and processing large quantities of undifferentiated hESCs is a challenging task. Conventionally, hESCs are passaged as clusters, which can limit their growth efficiency and use in downstream applications. This study demonstrates that hESCs can be passaged as single cells using Accutase, a formulated mixture of digestive enzymes. In contrast to trypsin treatment, Accutase treatment does not significantly affect the viability and proliferation rate of hESC dissociation into single cells. Accutase‐dissociated single cells can be separated by FACS and proliferate as fully pluripotent hESCs. An Oct4–eGFP reporter construct engineered into hESCs was used to monitor the pluripotency of hESCs passaged with Accutase. Compared to collagenase‐passaged hESCs, Accutase‐treated cultures contained a larger proportion of undifferentiated (Oct4‐positive) cells. Additionally, Accutase‐passaged undifferentiated hESCs could be grown as monolayers without the need for monitoring and/or selection for quality hESC colonies. Mol. Reprod. Dev. 75: 818–827, 2008. © 2007 Wiley‐Liss, Inc.