bluuebunny/crossref_metadata_2025 huggingface dataset:
Future perspectives of selective estrogen receptor modulators used alone and in combination with DHEA
Authors: Labrie F
Published: May 2006

Breast cancer is the most frequently diagnosed and the second cause of cancer death in women, thus making breast cancer a most feared disease. Since breast cancer metastasizes early and it is unlikely that improvements in the treatment of metastatic disease could permit a cure in most cases in the foreseeable future, it is clear that prevention is essential in order practically to eliminate deaths from breast cancer. Tamoxifen is the only selective estrogen receptor modulator (SERM) currently registered for use in breast cancer prevention; the tamoxifen versus raloxifene study should indicate the efficacy of this compound compared with raloxifene. The recent benefits of aromatase inhibitors over tamoxifen indicate the advantages of a blockade of estrogens more complete than the one achieved with tamoxifen, a SERM having some estrogenic activity in the mammary gland and an even higher estrogenic action in the uterus. However, it is unlikely that the general estrogen ablation achieved with aromatase inhibitors will be acceptable for the long-term use required for prevention. It is thus important to develop SERMs with highly potent and pure antagonistic activity in the mammary gland and uterus while possessing estrogen-like activity in tissues of particular importance for women’s health, namely the bones and the cardiovascular system. However, it is expected that a SERM alone will not meet all the requirements of women’s health at the postmenopause when ovarian estrogen secretion has ceased and peripheral formation of androgens and estrogens from DHEA by intracrine mechanisms is decreased by 60% or more. One possibility is to combine a SERM with DHEA, a precursor of sex steroids that permits, somewhat like SERMs, tissue-specific formation of androgens and/or estrogens according to the level of expression of the steroidogenic and steroid-inactivating enzymes. DHEA could thus compensate for the important loss of androgens that accompanies aging and could also permit sex steroid formation and action in the brain while breast cancer prevention would be achieved by the SERM.
A meta-iodobenzylguanidine scintigraphic scoring system increases accuracy in the diagnostic management of pheochromocytoma
Authors: Cecchin D , Lumachi F , Marzola M C , Opocher G , Scaroni C , Zucchetta P , Mantero F , Bui F
Published: May 2006

As observed by other authors, normal adrenal medullary tissue frequently gives an apparently positive meta-iodobenzylguanidine (MIBG) scan in cases studied using 123I-MIBG and less frequently 131I-MIBG. The aim of this study was to assess the usefulness of a scoring system, based on different uptakes of the radiopharmaceutical, to improve the accuracy of 123I-MIBG scintigraphy in patients with either adrenal or extra-adrenal pheochromocytomas. Charts from 67 consecutive patients (29 males and 38 females, median age 48 years, range 14–80 years) with suspected pheochromocytoma (either sporadic or familial: multiple endocrine neoplasia (MEN) 2a, MEN2b, Von Hippel–Lindau, neurofibromatosis type 1) who underwent 123I-MIBG scintigraphy (scans acquired 4–24 h after injection) from 1991 to 2004, were independently reviewed by two experienced nuclear medicine physicians using liver uptake as a reference (scores: 1, uptake absent or less than the liver; 2, equal to the liver; 3, moderately more intense than the liver; 4, markedly more intense than the liver). Interfering medications were discontinued for the appropriate time before MIBG injection. Histological data were obtained for all patients who underwent adrenalectomy. Scintigraphies were classified as positive using the following criteria: extra-adrenal focal uptake, adrenal enlargement together with non-homogeneous uptake and adrenal uptake more intense than the liver (score 3–4). After surgical resection, as confirmed by histological findings and long-term follow-up (range 1–14 years, average 9.25 years), 43 patients were considered true positives using the proposed scoring system, 20 were true negatives, four were false negatives and none was false positive. In conclusion, the proposed scoring system demonstrated high specificity (100%), sensitivity (91.5%) and accuracy (94%) in the management of pheochromocytoma. Positive predictive value and negative predictive value were 100% and 83.3% respectively. Normal adrenal tissue uptake was correctly discriminated from pheochromocytomas in 18 out of 20 patients, with adrenal uptake equal to the liver (grade 2), using the proposed cut-off level.
Correlation between B-RAFV600E mutation and clinico–pathologic parameters in papillary thyroid carcinoma: data from a multicentric Italian study and review of the literature
Authors: Fugazzola L , Puxeddu E , Avenia N , Romei C , Cirello V , Cavaliere A , Faviana P , Mannavola D , Moretti S , Rossi S , Sculli M , Bottici V , Beck-Peccoz P , Pacini F , Pinchera A , Santeusanio F , Elisei R
Published: May 2006

Recently, a somatic point mutation of the B-RAF gene (V600E) has been identified as the most common genetic event in papillary thyroid carcinoma (PTC), with a prevalence variable among different series. Since discordant data on the clinico-pathologic features of B-RAF mutated PTC are present in the literature, the aim of the present co-operative study was to establish the prevalence of this genetic alteration and to perform a genotype–phenotype correlation in a large cohort of patients with PTC. To this purpose, a series of 260 sporadic PTCs with different histological variants were included in the study. The mutational analysis of the B-RAF gene was performed either by RT-PCR followed by single-stranded conformational polymorphism or by PCR and direct sequencing. Statistical analyses were obtained by means of χ2/Fisher’s exact test and t-test. Overall, a heterozygous T > A transversion at nucleotide 1799 (V600E) was found in 99 out of 260 PTCs (38%). According to the histological type of the tumor, the B-RAF V600E mutation was present in 48.3% of cases of classic PTCs (85 out of 176), in 17.6% (nine out of 51) of follicular variants of PTCs, in 21.7% (five out of 23) in other PTC variants and in none of the ten poorly differentiated tumors. B-RAF V600E was significantly associated with the classic variant of PTC (P = 0.0001) and with an older age at diagnosis (P = 0.01). No statistically significant correlation was found among the presence of B-RAF V600E and gender, tumor node metastasis (TNM), multicentricity of the tumor, stage at diagnosis and outcome. In conclusion, the present study reports the prevalence of B-RAF V600E (38%) in the largest series of sporadic PTCs, including 260 cases from three different Italian referring centers. This prevalence is similar to that calculated by pooling together all data previously reported, 39.6% (759 out of 1914 cases), thus indicating that the prevalence of this genetic event lies around 38–40%. Furthermore, B-RAF V600E was confirmed to be associated with the papillary growth pattern, but not with poorer differentiated PTC variants. A significant association of B-RAF mutation was also found with an older age at diagnosis, the mutation being very rare in childhood and adolescent PTCs. Finally, no correlation was found with a poorer prognosis and a worse outcome after a median follow-up of 72 months.
VEGF-C and COX-2 expression in papillary thyroid cancer
Authors: Siironen Päivi , Ristimäki Ari , Narko Kirsi , Nordling Stig , Louhimo Johanna , Andersson Sture , Haapiainen Reijo , Haglund Caj
Published: May 2006

In papillary thyroid cancer (PTC), age appears to be the most important single prognostic factor. Another characteristic feature is the lack of association between survival and lymph node metastases. Earlier, we found that expression of cyclooxygenase-2 (COX-2) is higher in older PTC patients, in agreement with the finding that older patients have a worse prognosis. Recent findings suggest that COX-2 can up-regulate vascular endothelial growth factor-C (VEGF-C) expression. Here, we investigated whether expression of VEGF-C differs between young and older PTC patients and whether expression of VEGF-C and COX-2 are correlated. Our retrospective study comprised 106 PTC patients selected by age: those under 35 or over 55 at diagnosis. Paraffin-embedded tissue samples were analysed by immunohistochemistry for VEGF-C protein expression. Furthermore, we investigated by quantitative RT-PCR and enzyme immunoassay the relationship between VEGF-C and COX-2 expression in papillary thyroid cancer cells (NPA cells). VEGF-C expression was significantly increased with age. In the tumours from older lymph node-positive (N1) patients, VEGF-C expression was significantly higher than in the tumours from young N1 patients. Moreover, all patients who died of cancer or who developed distant metastases were old, and most tumours from these patients (4 of 5) expressed VEGF-C and had had nodal metastases at the time of primary operation. Immunohistochemically, expression of COX-2 and VEGF-C correlated strongly. In cell culture, this correlation was not so clear, because the COX-2 selective inhibitor, NS-398, did not reduce VEGF-C expression. However, as both COX-2 and VEGF-C were induced by the tumour promoter phorbol 12-myristate 13-acetate (PMA), the same factors may control them both.
Is oestrogen receptor- β a predictor of endocrine therapy responsiveness in human breast cancer?
Authors: Murphy Leigh C , Watson Peter H
Published: May 2006

The role of oestrogen receptor (ER) β in human breast cancer remains unclear. However, it is now apparent that when considering ER β in human breast cancer it is important to recognise two ER β expressing groups, one in which ER β is co-expressed with ER α and the other where ERβ is expressed alone. Emerging data support different functions between ER β when it is expressed alone and when it is co-expressed with ER α. With regard to the latter group (ER α +/ER β +), there are now 9 out of 10 retrospective clinical outcome studies published, that support the hypothesis that increased expression of ER β is associated with increased likelihood of response to endocrine therapy. The data strongly support undertaking prospective studies to determine if the addition of ERβ to ER α is clinically beneficial and whether to include both ER β and ER α when establishing clinically relevant cut-offs for defining ER status.
Insulin-like growth factor-I, its binding proteins (IGFBP-1 and IGFBP-3), and growth hormone and breast cancer risk in The Nurses Health Study II
Authors: Schernhammer Eva S , Holly Jeff M , Hunter David J , Pollak Michael N , Hankinson Susan E
Published: May 2006

Earlier data suggest that the relationship between circulating insulin-like growth factor I (IGF-I) levels and breast cancer risk differs according to menopausal status. We evaluated the association between IGF levels as well as the primary regulator of IGF-I production, growth hormone (GH), and breast cancer risk in the Nurses’ Health Study II (NHS II) cohort, a large cohort of primarily premenopausal women. We conducted a case-control study nested within the prospective NHS II cohort. Plasma concentrations of IGF-I, IGF binding protein (IGFBP)-3, IGFBP-1, and GH were measured in blood samples collected between 1996 and 1999. Totally 317 women were identified who had a diagnosis of invasive or in situ breast cancer between the date of blood collection and June 1 2003; 75% of these women were premenopausal at blood collection. To each of the 317 women, two controls were age-matched for a total of 634 controls. We used conditional logistic regression models to estimate the relative risk of breast cancer. Overall, plasma IGF-I, IGFBP-1, IGFBP-3, and GH levels were not associated with breast cancer risk (relative risks, top vs bottom quartile; IGF-I, 0.98, 95% confidence interval (CI), 0.69–1.39; IGFBP-1, 0.95, 95% CI, 0.63–1.41; IGFBP-3, 1.10, 95% CI, 0.78–1.54; GH, 1.09, 95% CI, 0.82–1.46). These risks were similar for premenopausal women of age 45 years or less. Further adjustment for additional breast cancer risk factors did not change these estimates. In conclusion, circulating IGF-I, IGFBP-1, IGFBP-3, and GH levels appear to have no important association with breast cancer risk in a large cohort of premenopausal women.
IGF-I, IGFBP-3 and breast cancer risk in women: The European Prospective Investigation into Cancer and Nutrition (EPIC)
Authors: Rinaldi S , Peeters P H M , Berrino F , Dossus L , Biessy C , Olsen A , Tjonneland A , Overvad K , Clavel-Chapelon F , Boutron-Ruault M C , Téhard B , Nagel G , Linseisen J , Boeing H , Lahmann P H , Trichopoulou A , Trichopoulos D , Koliva M , Palli D , Panico S , Tumino R , Sacerdote C , van Gils C H , van Noord P , Grobbee D E , Bueno-de-Mesquita H B , Gonzalez C A , Agudo A , Chirlaque M D , Barricarte A , Larrañaga N , Quiros J R , Bingham S , Khaw K T , Key T , Allen N E , Lukanova A , Slimani N , Saracci R , Riboli E , Kaaks R
Published: May 2006

Blood concentrations of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) have recently been associated with breast cancer risk, notably in women who developed breast cancer at a young age. Prospective studies published so far, however, were relatively small and odds ratio (OR) estimates imprecise. We present the results of a large prospective case-control study nested within the European Prospective Investigation into Cancer and Nutrition on total IGF-I, IGFBP-3 and breast cancer risk including 1081 incident cases of invasive breast cancer and 2098 matched control subjects. Increasing IGF-I and IGFBP-3 concentrations were associated with a significant increase in breast cancer risk in women who developed breast cancer after 50 years of age (highest vs lowest quintile OR 1.38 (95% confidence interval (CI) 1.02–1.86), P = 0.01, and 1.44 (95% CI 1.04–1.98), P = 0.01, respectively), but no relationship was observed in younger women (OR = 1.03 (95% CI 0.60–1.77), P = 0.81 for IGF-I, and OR = 0.92 (95% CI 0.50–1.70), P = 0.69 for IGFBP-3). There was, however, significant heterogeneity in the relationship of breast cancer with serum IGF-I and IGFBP-3 levels depending on the time interval between blood donation and tumor diagnosis. A reduction in breast cancer risk with increasing IGF-I concentrations was observed in cases with a diagnosis of cancer less than 2 years after blood donation, (OR = 0.76 (95% CI 0.57–1.03)), while an increase in risk was observed for women with a later diagnosis (above or equal to two years after blood collection, OR = 1.51 (95% CI 1.19–1.91)). A similar pattern was observed for IGFBP-3. This study confirms previous findings for an association of serum IGF-I and IGFBP-3 concentrations with breast cancer risk, particularly for women with a later diagnosis of cancer, but it does not support the hypothesis of an involvement of IGF-I in younger women.
Gene expression profiles of progressive pancreatic endocrine tumours and their liver metastases reveal potential novel markers and therapeutic targets
Authors: Capurso G , Lattimore S , Crnogorac-Jurcevic T , Panzuto F , Milione M , Bhakta V , Campanini N , Swift S M , Bordi C , Fave G Delle , Lemoine N R
Published: May 2006

The intrinsic nature of tumour behaviour (stable vs progressive) and the presence of liver metastases are key factors in determining the outcome of patients with a pancreatic endocrine tumour (PET). Previous expression profile analyses of PETs were limited to non-homogeneous groups or to primary lesions only. The aim of this study was to investigate the gene expression profiles of a more uniform series of sporadic, non-functioning (NF) PETs with progressive disease and, for the first time, their liver metastases, on the Affymetrix human genome U133A and B GeneChip set. Thirteen NF PET samples (eight primaries and five liver metastases) from ten patients with progressive, metastatic disease, three cell lines (BON, QGP and CM) and four purified islet samples were analysed. The same samples were employed for confirmation of candidate gene expression by means of quantitative RT-PCR, while a further 37 PET and 15 carcinoid samples were analysed by immunohistochemistry. Analysis of genes differentially expressed between islets and primaries and metastases revealed 667 up- and 223 down-regulated genes, most of which have not previously been observed in PETs, and whose gene ontology molecular function has been detailed. Overexpression of bridging integrator 1 (BIN1) and protein Z dependent protease inhibitor (SERPINA10) which may represent useful biomarkers, and of lymphocyte specific protein tyrosine kinase (LCK) and bone marrow stromal cell antigen (BST2) which could be used as therapeutic targets, has been validated. When primary tumours were compared with metastatic lesions, no significantly differentially expressed genes were found, in accord with cluster analysis which revealed a striking similarity between primary and metastatic lesions, with the cell lines clustering separately. We have provided a comprehensive list of differentially expressed genes in a uniform set of aggressive NF PETs. A number of dysregulated genes deserve further in-depth study as potentially promising candidates for new diagnostic and treatment strategies. The analysis of liver metastases revealed a previously unknown high level of similarity with the primary lesions.
Effects of oestrogen on gene expression in epithelium and stroma of normal human breast tissue
Authors: Wilson C L , Sims A H , Howell A , Miller C J , Clarke R B
Published: May 2006

Oestrogen (E) is essential for normal and cancer development in the breast, while anti-oestrogens have been shown to reduce the risk of the disease. However, little is known about the effect of E on gene expression in the normal human breast, particularly when the epithelium and stroma are intact. Previous expression profiles of the response to E have been performed on tumour cell lines, in the absence of stroma. We investigated gene expression in normal human breast tissue transplanted into 9–10-week-old female athymic nude (Balb/c nu/nu) mice. After 2 weeks, when epithelial proliferation is minimal, one-third of the mice were treated with 17β-oestradiol (E2) to give human luteal-phase levels in the mouse, which we have previously shown to induce maximal epithelial cell proliferation. RNA was isolated from treated and untreated mice, labelled and hybridized to Affymetrix HG-U133A (human) GeneChips. Gene expression levels were generated using BioConductor implementations of the RMA and MAS5 algorithms. E2 treatment was found to represent the largest source of variation in gene expression and cross-species hybridization of mouse RNA from xenograft samples was demonstrated to be negligible. Known E2-responsive genes (such as TFF1 and AREG), and genes thought to be involved in breast cancer metastasis (including mammoglobin, KRT19 and AGR2), were upregulated in response to E treatment. Genes known to be co-expressed with E receptor α in breast cancer cell lines and tumours were both upregulated (XBP-1 and GREB1) and downregulated (RARRES1 and GATA3). In addition, genes that are normally expressed in the myoepithelium and extracellular matrix that maintain the tissue microenvironment were also differentially expressed. This suggests that the response to oestrogen in normal breast is highly dependent upon epithelial–stromal/myoepithelial interactions which maintain the tissue microenvironment during epithelial cell proliferation.
Three soil improvement methods and their applications to road construction
Authors: Chu J. , Yan S. W. , Zheng Y. R.
Published: May 2006

To cater for the massive development in transportation infrastructure in China, several innovative soil improvement methods have been developed in recent years. In this paper, three methods that are applicable to the improvement of soft ground, namely the vacuum preloading method, the explosive replacement method and the dynamic consolidation method, are introduced. Case studies are presented to illustrate the applications of each method in road or runway constructions. The principles and techniques related to each method are explained. The advantages and disadvantages of each method are discussed and compared. The limitations of each method are also highlighted.

Pour faire face aux développements gigantesques de l'infrastructure de transport en Chine, plusieurs méthodes innovantes pour l'lamélioration des sols ont été développées ces dernières années. Dans cet exposé, nous présentons trois méthodes qui sont applicables à l'amélioration de sols tendres, nommément la méthode de précharge sous vide, la méthode de remplacement explosif et la méthode de consolidation dynamique. Nous présentons des études de cas pour illustrer les applications de chaque méthode à la construction de routes ou de pistes de décollage. Nous expliquons les principes et techniques liés à chacune de ces méthodes. Nous analysons et comparons leurs avantages et leurs inconvénients. Nous montrons aussi leurs limitations.
Coreflood Studies Examine New Technologies That Minimize Intervention Throughout Well Life Cycle
Authors: Jordan M. M. , Collins I. R. , Gyani A. , Graham G. M.
Published: May 2006

With the development of more and more subsea fields, the challenge for scale-inhibitor squeeze treatments is to reduce intervention frequency by extending squeeze treatment lifetime while con-comitantly reducing any potential damage in both low water-cut and high water-cut wells. This paper discusses the technical problems and examines new technologies for treatment of such production wells through their life cycle. This paper covers the findings from late 2001 through early 2002. Because even newer technologies have been developed since the writing of this paper, it should be read as the history of technological development.

Scale control technology available to control scale formation within the reservoir and near-wellbore area of production wells will be outlined with a focus on the current developing technology to control scale within low water-cut wells. Moreover, this paper shows that the new technical area of emulsion-scale-inhibitor-delivery systems, originally designed to control scale within low water-cut wells, has applications in both low and high water-cut wells.

This study assists in developing an understanding of the mechanism of interaction of emulsion-based products—in particular, the impact of the level of water saturation within the core system. In addition, it demonstrates that the emulsion particles are retained in the core matrix during both crude and brine flowback. This paper indicates that the emulsion product offers the potential for extremely long squeeze lifetimes with minimal damage in oil-production wells with rising water cut. It also demonstrates how different technologies have their own place in the life cycle of a production well.
Consideration of Damaged Zone in a Tight Gas Reservoir Model With a Hydraulically Fractured Well
Authors: Behr Aron , Mtchedlishvili George , Friedel Torsten , Haefner Frieder
Published: May 2006

This paper provides a detailed description of conditions in the hydraulically damaged fracture environment after closure and how to integrate them into a reservoir-simulation model.

A special model-initialization algorithm was developed and realized in a support tool to make possible the computing of a post-fracture performance in tight gas formations by a reservoir simulator. The input represents the treatment schedule of the fracturing process and some results produced by commercial fracturing packages or geophysical measurements.

To represent the fracture geometry and properties, the information about the distribution of the proppant concentration in the fracture as well as the fracture-width variation is translated into the permeabilities and porosities of the fracture gridblocks. To determine the fracturing-fluid saturation in the invaded zone, a new approach was derived to imitate the fracture propagation at a fracturing period under consideration of the leakoff processes. The penetration of the fracturing fluid into the matrix was modeled by the Buckley-Leverett equations for two-phase nonmiscible displacement, with boundary conditions provided by a classical leak-off theory.

The approach is illustrated with a simulation model prepared for the analysis of the cleanup process in a damaged fractured well within a Rotliegende tight gas formation in north Germany.
A Novel Laboratory Method for Assessing the Erosional Characteristics of Mudcakes
Authors: Amanullah Md.
Published: May 2006

Design and development of superior drilling and drill-in fluids and the assessment of the effectiveness of mudcake cleaning from the borehole wall by cleaning systems require a good understanding of the fundamental phenomena associated with the erosional behavior of mudcakes formed by different mud systems. Because of serious consequences of mudcake erosion on the formation damage potential of drilling muds and mudcake cleaning before a cementation job, it is important to have a suitable, simple, and field-applicable method for predicting the erosional potential of mudcakes formed by muds of different chemical composition. The prediction of erosion behavior is essential to screen and select appropriate mud additives and also to design new mud products for producing good-quality mudcakes on the borehole wall. The technique and technology could provide a suitable means to assess the effectiveness of mudcake cleaning systems and to help design such cleaning systems for removal of mudcake from the borehole wall.

Cakes formed by several water-based muds were evaluated using the newly developed technique. The testing has been performed with the simulation of hydrodynamic conditions corresponding to the drill-collar borehole-annular section of a wellbore. The results indicate that the presence of electrolytes significantly increases the erosion coefficient of bentonite mudcake. Ionic fluid-loss additives such as polyanionic cellulose (PAC) and carboxy-methyl cellulose (CMC) reduced the erosion behavior of saltwater-based bentonite mudcake significantly. However, the presence of the polyanionic fluid-loss additive PAC caused a drastic reduction in the erosion characteristic of NaCl-based saltwater mud compared to the presence of the anionic fluid-loss additive CMC. The presence of the nonionic fluid-loss additive, modified starch, shows little improvement of erosional behavior of saltwater-based mudcake. It seems to be that the electrochemical forces of interactions of ionic fluid-loss additives play a vital role in making a mudcake nonerodible. The variation of the erosional characteristics of the mudcakes is attributable to the physical, chemical, and electrical properties of the cake-forming mud additives and also to the nature of the fabrics formed by these additives within the mudcake matrix.
Impact on Scale Management of the Engineered Depressurization of Waterflooded Reservoirs: Risk Assessment Principles and Case Study
Authors: Chekani M. , Mackay E. J.
Published: May 2006

Increased oil and particularly gas production may be achieved in waterflooded reservoirs by stopping further water injection and depressurizing the reservoir to release solution gas. Pressure depletion may be accelerated by backproducing injected brines. However, there is the possibility that these brines may cause formation damage by mobilizing fines or deposition of inorganic scales. Scale deposition in production wells may also occur as a result of pressure depletion, with calcite scales being precipitated when the system drops below the CO2 bubblepoint pressure. This paper discusses the assessment and prediction of scale-related formation damage problems that are likely to occur during depressurization of a case study field. The potential for the specific problem arises from the formation of barium sulfate scale as a result of mixing of injected and formation brines during production. Data used in this study include well brine chemistries and an existing finite-difference reservoir simulation model of the field depressurization, which was used to calculate the mixing of injected and formation brines and the movement of the mixing and temperature fronts during waterflooding and subsequent depressurization.

This study has determined that the behavior of the scaling potential for each well in this field is different. Also, the degree of scaling, both deep within the reservoir where it does the least damage and around the wellbore (for both injectors and producers) where it may adversely affect production, can be predicted by detailed modeling using both conventional and reaction flow simulations. Former injectors converted to water production or infill wells drilled in the aquifer for pressure depletion may experience an increase in the scaling potential that significantly impacts the economics of the project because of the need for extensive prevention (inhibition) treatments. The increased scaling potential in these wells is a result of the dynamics of brine mixing in the reservoir, the lowering of reservoir temperature in the vicinity of injection wells during waterflooding, and the large volumes of water required to be produced to achieve depressurization. The magnitude of the scaling problem and the economic impact are lower for the production wells because of lower water production rates and higher temperatures.
Optimization of Commingled Production Using Infinitely Variable Inflow Control Valves
Authors: Naus N. M. J. J. , Dolle N. , Jansen J. -D.
Published: May 2006

We developed an operational strategy for commingled production with infinitely variable inflow control valves (ICVs) using sequential linear programming (SLP). The optimization algorithm requires instantaneous and derivative information. We propose a workflow in which the production engineer relies on measurements to determine the flow rate and pressure values and on models to determine the derivative information (i.e., the changes in flow rates as a result of a change in an ICV setting). Such a model typically would be a steady-state wellbore simulator including choke models to represent the ICVs and inflow models to represent the near-well reservoir flow in the various zones. The parameters of the model need to be updated regularly using real-time measurements and production tests, and we discuss the impact of different smart-well instrumentation levels on the updating process.

We simulated the performance of this production-optimization strategy in a reservoir simulator. Some numerical aspects of the algorithm and problems encountered during implementation are discussed. The performance of the algorithm was tested in two reservoir settings. In both cases, the optimization resulted in accelerated oil production compared to conventional, surface-controlled production. However, accelerated production did not always result in higher ultimate recovery compared to the conventional case. In such situations, the benefits of either short-term production optimization (accelerating production) or long-term reservoir management (maximizing recovery) should be weighed.
Integrating Soil and Weather Data to Describe Variability in Plant Available Nitrogen
Authors: Kay B. D. , Mahboubi A. A. , Beauchamp E. G. , Dharmakeerthi R. S.
Published: May 2006

Although there are economic and environmental reasons to manage fertilizer‐nitrogen (N) more effectively in variable landscapes, the impact of weather and its interaction with soil properties/landscape attributes or management practices has received little attention. The objectives of this study were to assess the magnitude of temporal and spatial variability in soil and plant N in a variable landscape under different management practices and to assess the dependence of their temporal variability on readily available weather variables such as air temperature and rainfall. The experiment was conducted from 1997 to 2003 on a simple slope under three maize (Zea mays L.) based cropping systems. Soil and shoot N were measured through the growing season and the sum used as a measure of plant available N (PAN). Values of PAN varied with year, treatment, landscape position, and year × treatment and year × treatment × position interaction terms. The effects were quantified for each management treatment using multiple regression analyses to relate PAN to soil organic carbon (OC), cumulative degree days (CDD), and cumulative rainfall (CRF) in different periods within the growing season. Plant Available Nitrogen was most strongly influenced by rainfall early in the growing season and exhibited a nonlinear response to OC and CRF. The regression model predicted spatial patterns that were generally stable when applied to historical weather data; PAN increased with OC in 12 of the 15 yr. The analyses illustrate the feasibility of combining soils and weather data to predict N dynamics in variable landscapes.
Examining Changes in Soil Organic Carbon with Oat and Rye Cover Crops Using Terrain Covariates
Authors: Kaspar T. C. , Parkin T. B. , Jaynes D. B. , Cambardella C. A. , Meek D. W. , Jung Y. S.
Published: May 2006

Winter cover crops have the potential to increase soil organic C in the corn (Zea maysL.)–soybean [Glycine max(L.) Merr.] rotation in the upper Midwest. Management effects on soil C, however, are often difficult to measure because of the spatial variation of soil C across the landscape. The objective of this study was to determine the effect of oat (Avena sativaL.), rye (Secale cerealeL.), and a mixture of oat and rye used as winter cover crops following soybean on soil C levels over 3 yr and both phases of a corn–soybean rotation using terrain attributes as covariates to account for the spatial variability in soil C. A field experiment was initiated in 1996 with cover crop treatments, both phases of a corn–soybean rotation, and a controlled‐traffic no‐till system. Oat, rye, and oat–rye mixture cover crop treatments were overseeded into the soybean phase of the rotation in late August each year. Cover crop treatments were not planted into or after the corn phase of the rotation. Soil C concentration was measured on 450 samples taken across both rotation phases in a 7.62‐m grid pattern in the late spring of 2000, 2001, and 2002. Slope, relative elevation, and wetness index (WI) were used as covariates in the analysis of variance to remove 77% of the variation of soil C caused by landscape driven patterns of soil C. Soil C concentrations were 0.0023 g C g soil−1higher in 2001 and 0.0016 g C g soil−1higher in 2002 than in 2000. The main effects of cover crops were not significant, but the interaction of cover crops and rotation phase was significant. The rye cover crop treatment had 0.0010 g C g soil−1higher soil C concentration than the no‐cover‐crop control in the soybean phase of the rotation, which included cover crops, but had 0.0016 g C g soil−1lower C concentrations than the control in the corn phase of the rotation, which did not have cover crops. Using terrain covariates allowed us to remove most of the spatial variability of soil C, but oat and rye cover crops planted every other year after soybean did not increase soil C concentrations averaged over years and rotation phases.
Interpolating Soil Properties Using Kriging Combined with Categorical Information of Soil Maps
Authors: Liu Ten-Lin , Juang Kai-Wei , Lee Dar-Yuan
Published: May 2006

Kriging interpolation is frequently used for mapping soil properties in the analysis and interpretation of spatial variation of soil. Mapping quality could affect the performance of site‐specific management. Soil map–delineation in existing soil maps showing abrupt changes at the boundaries between different soil types can provide valuable categorical information for interpreting variation in soil properties. In this study, map units were used to group sampled observations, and the variation in soil properties was separated into two parts: (i) between soil types (i.e., soil type effect) and (ii) within each soil type (i.e., residual). A kriging model combined with soil map–delineation, taking into account the variation components of soil type effect and residual, was proposed. A comparison of performance of kriging combined with soil map–delineation (KSMD) and ordinary kriging (OK) was performed to assess the feasibility of KSMD for improving the interpolation of soil properties. Real data of soil properties (sand, silt, and clay contents; pH; and Mehlich‐3 Ca and P) in a field of midwestern Taiwan were used for illustration. The analysis of variance table revealed that the contribution of soil types is a significant source of the spatial variation of soil. The spatial variation components of soil type effect and residual were thus determined for KSMD. When comparing KSMD and OK, the mean errors of KSMD and OK estimations were similar. However, decreases in estimation of imprecision for KSMD relative to OK (DIP %) for the 127 validation locations for sand, silt, and clay contents; pH; and Mehlich‐3 Ca and P were 34, 40, 48, 20, 42, and 3%, respectively. These results suggested that the proposed KSMD method could use the information of soil map–delineation to increase precision of the interpolation of soil properties.
Indicator of Reduction in Soil (IRIS)
Authors: Castenson Karen L. , Rabenhorst Martin C.
Published: May 2006

Research and management of wetlands often requires the documentation of reducing soil conditions. Documentation of reduction in soils by measuring oxidation–reduction (redox) potentials using Pt electrodes is often difficult because of the time and cost involved in employing these techniques. This study evaluated a new procedure called Indicator of Reduction in Soil (IRIS) that has been recently developed to assist in the detection of reduced soil conditions. Polyvinyl‐chloride (PVC) tubes coated with a ferrihydrite paint were inserted into the upper 50 cm of the soil for periods of 12 to 32 d. Soil redox potentials, water table height, and soil temperature were measured concurrently. Upon removal, the tubes were analyzed to assess the loss of ferrihydrite paint from the tube surface. When ferrhydrite paint was substantially depleted from 20% of the area of the IRIS tube, 87% of the observations at the corresponding depth indicated the soil was reduced. When ferrhydrite paint was substantially depleted from 30% of the area of the IRIS tube, essentially all of the soil observations at corresponding depths showed that the soil was reduced. Although not without complications, IRIS tubes appear to be a promising new alternative to traditional methods used to identify reducing conditions in soil.
Prediction of Gross and Net Nitrogen Mineralization‐Immobilization‐Turnover from Respiration
Authors: Luxhøi Jesper , Bruun Sander , Stenberg Bo , Breland Tor A. , Jensen Lars S.
Published: May 2006

Prediction of net N mineralization is required for optimization of the synchronization of N supply with plant N demand. Net N mineralization is the outcome of two concurrent and oppositely directed processes: gross N mineralization and gross N immobilization turnover (MIT). Consequently, an improved understanding of MIT can potentially improve our capability to predict net N mineralization patterns. The aim of the study was to measure MIT and respiration rates of widely differing plant materials and look for relations between them. Eight plant residues with a very wide range in C to N ratios were incorporated into soil and incubated at 16°C. During 2‐d intervals (5–6, 25–26, and 55–56 d after incorporation), MIT and respiration rates were determined. The respiration and gross N immobilization rates were correlated (R2= 0.74), whereas respiration and gross N mineralization rates were less well correlated (R2= 0.41). The correlation was improved (R2= 0.89) when only the data from the first incubation period and the C/N ratio of acid detergent solubles (ADS) were taken into account. Assuming that the soil microorganisms have a C use efficiency of 50%, this study showed that the gross N mineralization rate made up only 30% of the total gross litter N decomposition rate (i.e., the remaining 70% being directly assimilated by soil microorganisms in organic form). Net N mineralization rates, derived from the difference between predicted rates of gross N mineralization and gross N immobilization, could explain up to 64% of the variability in measured net N mineralization rates. In conclusion, this study revealed that MIT in the initial phase of decomposition can be derived from data on C mineralization and the C/N ratio of ADS, which can simplify the process of calibrating and validating mechanistic models and thereby improve our capability of predicting net N mineralization.
Comparison of American Society of Testing Materials and Soil Science Society of America Hydrometer Methods for Particle‐Size Analysis
Authors: Keller J. M. , Gee G. W.
Published: May 2006

Particle‐size analysis (PSA) is widely used in both soil science and engineering. Soil classification schemes are built on PSA values and recent developments in pedotransfer functions rely on PSA to estimate soil hydraulic properties. Because PSA is method dependent, the standardization of experimental procedures is important for the comparison of reported results. A study was conducted to compare the American Society of Testing Materials (ASTM) hydrometer method (D422) for PSA with the hydrometer method published by the Soil Science Society of America (SSSA). Tests on soils ranging in texture from sand to sandy clay loam were conducted at temperatures ranging from 20 to 30°C. The main difference between methods is the temperature correction, with the ASTM method relying on an empirical correction and the SSSA method using a blank hydrometer reading. Identical texture estimates for all but one of 48 total samples was observed between methods. Percentage of fines, silt, and clay demonstrated relatively consistent values between methods. The ASTM and SSSA methods were compared at values of D50, D30, and D10 (i.e., effective particle diameter values when the size‐distributions have dropped to percentages of less than 50, 30, and 10, respectively). Excellent agreement was found between methods for D50 and D30 values (correlations above 0.99). Less agreement was found for D10 (correlation 0.989) values, but still reasonably good. The results suggest that for the range of soil textures evaluated in this study, ASTM and SSSA methods can be used interchangeably for textural analysis.
A Modified Soil Diffusion Chamber for Gas Profile Analysis
Authors: Yu Kewei , DeLaune Ronald D.
Published: May 2006

Gas concentration gradients in soil profiles can provide important information on the timing and location of gas production and consumption. High spatial variation complicates both determination of soil gas profile concentration or gradient and calculation of the gaseous flux from soil. A modified diffusion chamber is introduced in this paper with advantages of gas sampling at multiple depths at a single location, easy installation and less maintenance. Field measurement using both original chamber (requiring multiple installations at various depths) and the modified chamber techniques showed comparable soil CO2 and CH4 profile gradients.
Did the Cypriot Students Really Cheat on TIMSS?
Authors: Papanastasiou Elena C. , Zembylas Michalinos
Published: May 2006

Over the last few years, data obtained from high school seniors for the Third International Mathematics and Science Study (TIMSS, 1995) has led to several simplistic and controversial interpretations. One of these controversies is related to the results from Cyprus: although Cypriot students did not perform well in mathematics in elementary, middle school, and in the non-advanced sectors of high school, the students in the advanced mathematics courses managed to perform exceptionally well. In a previous article, an American commentator has suggested that either Cyprus has a dual educational system or Cypriot students have cheated on this test. In this article, the authors revisit this claim and examine whether it is possible for an educational system that does not allow students to perform well in mathematics relative to other countries, to produce students who could perform exceptionally well when they are high school seniors.
Investigating Education for European Identity at Three ‘European Schools’: A Research Proposal
Authors: Savvides Nicola
Published: May 2006

Encouraging pupils to develop a sense of European identity is one of the implicit aims of the ‘European Schools’. This article describes a proposed research study, funded by the Economic and Social Research Council, which will investigate how this aim is being pursued at three European Schools. The proposal builds on two years (2003–2005) of preparation including research methods training, preliminary research and pilot work conducted at one of the three European Schools to be studied. The introduction to this article presents the contextual background and rationale to the proposed study, before moving on to a brief review of the empirical literature and the conceptual framework. Following this is a discussion of the general purpose of the research, outlining the research questions and the methods that will be used for gathering the data to answer them. The purpose in presenting the preliminary details of this project is to seek constructive criticism and suggestions from educational researchers, particularly from amongst comparativists and those working on European, international and intercultural dimensions. This proposal is designed to guide the project rather than to serve as a fixed framework. It may therefore be modified in light of the feedback received and as unforeseen avenues and new opportunities present themselves.
Every Student: Can Learn—IF…
Authors: Chickering Arthur W.
Published: May 2006

After forty-nine years of watching and working in higher education, Arthur Chickering has determined that three R's truly are fundamental to helping students learn. In stark contrast to the traditional set, Chickering's three R's challenge educators to recognize, respect, and respond to wide-ranging individual differences among diverse learners.
Jüngste Entwicklungen in der Metallabenzolchemie
Authors: Landorf Christopher W. , Haley Michael M.
Published: May 2006

Aromatische Metallacyclen sind zwar bereits seit 25 Jahren bekannt, seit dem Jahr 2000 hat dieses Forschungsgebiet aber einen deutlichen Aufschwung genommen. Dank neuer Synthesemethoden ist heute eine Vielzahl von Metallabenzolen zugänglich, die auch zuvor nicht vertretene Metallzentren enthalten. Aromatische Metallacyclen mit neuartigen Strukturen – Iridanaphthaline und Osmabenzine – wurden isoliert und charakterisiert. Die ersten Valenzisomere von Metallabenzolen – Iridabenzvalene und Rhodabenzvalene – wurden ebenso erhalten wie Konstitutionsisomere – die Isoosmabenzole. Der Aufsatz beschreibt die Synthese, die chemische Reaktivität und die physikalischen Eigenschaften dieser außergewöhnlichen aromatischen Verbindungen.
Recent Advances in Metallabenzene Chemistry
Authors: Landorf Christopher W. , Haley Michael M.
Published: May 2006

Research into aromatic metallacycles, though discussed in the literature over the last quarter century, has undergone a major expansion since 2000. A wide variety of new metallabenzenes, encompassing new synthetic methods and new metal centers, is now available. New aromatic metallacycle topologies (iridanaphthalene, osmabenzynes) have been isolated and characterized. The first metallabenzene valence isomers (iridabenzvalenes, rhodabenzvalenes) and constitutional isomers (isoosmabenzenes) are now known. This review discusses the synthesis, chemistry, and physical properties of these intriguing aromatic compounds.