bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cryopreservation of Neurospheres Derived from Human Glioblastoma Multiforme
Authors: Chong Yuk-Kien , Toh Tan-Boon , Zaiden Norazean , Poonepalli Anuradha , Leong Siew Hong , Ong Catherine Ee Ling , Yu Yiting , Tan Patrick B. , See Siew-Ju , Ng Wai-Hoe , Ng Ivan , Hande Manoor P. , Kon Oi Lian , Ang Beng-Ti , Tang Carol 
Published: October 2008

Abstract
Cancer stem cells have been shown to initiate and sustain tumor growth. In many instances, clinical material is limited, compounded by a lack of methods to preserve such cells at convenient time points. Although brain tumor-initiating cells grown in a spheroid manner have been shown to maintain their integrity through serial transplantation in immune-compromised animals, practically, it is not always possible to have access to animals of suitable ages to continuously maintain these cells. We therefore explored vitrification as a cryopreservation technique for brain tumor-initiating cells. Tumor neurospheres were derived from five patients with glioblastoma multiforme (GBM). Cryopreservation in 90% serum and 10% dimethyl sulfoxide yielded greatest viability and could be explored in future studies. Vitrification yielded cells that maintained self-renewal and multipotentiality properties. Karyotypic analyses confirmed the presence of GBM hallmarks. Upon implantation into NOD/SCID mice, our vitrified cells reformed glioma masses that could be serially transplanted. Transcriptome analysis showed that the vitrified and nonvitrified samples in either the stem-like or differentiated states clustered together, providing evidence that vitrification does not change the genotype of frozen cells. Upon induction of differentiation, the transcriptomes of vitrified cells associated with the original primary tumors, indicating that tumor stem-like cells are a genetically distinct population from the differentiated mass, underscoring the importance of working with the relevant tumor-initiating population. Our results demonstrate that vitrification of brain tumor-initiating cells preserves the biological phenotype and genetic profiles of the cells. This should facilitate the establishment of a repository of tumor-initiating cells for subsequent experimental designs.
Thromboxane A2 Induces Differentiation of Human Mesenchymal Stem Cells to Smooth Muscle-Like Cells
Authors: Kim Mi Ra , Jeon Eun Su , Kim Young Mi , Lee Jung Sub , Kim Jae Ho 
Published: October 2008

Abstract
Thromboxane A2 (TxA2) is involved in smooth muscle contraction and atherosclerotic vascular diseases. Accumulating evidence suggests a pivotal role for mesenchymal stem cells (MSCs) in vascular remodeling. In the present study, we demonstrate for the first time that the TxA2 mimetic U46619 induces differentiation of human adipose tissue-derived MSCs (hADSCs) to smooth muscle-like cells, as demonstrated by increased expression of smooth muscle-specific contractile proteins such as α-smooth muscle actin (α-SMA), calponin, smoothelin, and smooth muscle-myosin heavy chain. Using an in vitro collagen gel lattice contraction assay, we showed that U46619-induced expression of the contractile proteins was associated with increased contractility of the cells. U46619 increased the intracellular Ca2+ concentration in hADSCs and pretreatment of the cells with the thromboxane receptor antagonist SQ29548 or the calmodulin (CaM) inhibitor W13 abrogated the U46619-induced α-SMA expression and contractility, suggesting a pivotal role of Ca2+/CaM in the U46619-stimulated smooth muscle differentiation of hADSCs. In addition, U46619 elicited activation of RhoA in hADSCs, and pretreatment of the cells with the Rho kinase-specific inhibitor Y27632 or overexpression of the dominant-negative mutants of RhoA and Rho kinase blocked U46619-stimulated α-SMA expression and contractility. Furthermore, U46619 induced phosphorylation of myosin light chain (MLC) through CaM/MLC kinase- and Rho kinase-dependent pathways, and the MLC kinase inhibitor ML-7 abrogated U46619-induced α-SMA expression and contractility. These results suggest that U46619 induces differentiation of hADSCs to contractile smooth muscle-like cells through CaM/MLCK- and RhoA-Rho kinase-dependent actin polymerization.
Human Embryonic Stem Cell Differentiation Toward Regional Specific Neural Precursors
Authors: Erceg Slaven , Ronaghi Mohammad , Stojković Miodrag 
Published: October 2008

Abstract
Human embryonic stem cells (hESCs) are self-renewing pluripotent cells that have the capacity to differentiate into a wide variety of cell types. This potentiality represents a promising source to overcome many human diseases by providing an unlimited supply of all cell types, including cells with neural characteristics. Therefore, this review summarizes early neural development and the potential of hESCs to differentiate under in vitro conditions, examining at the same time the potential use of differentiated hESCs for therapeutic applications for neural tissue and cell regeneration.
Diagnosis of ecosystem impairment in a multiple-stress context—how to formulate effective river basin management plans
Authors: de Zwart Dick , Posthuma Leo , Gevrey Muriel , von der Ohe Peter C , Deckere de Eric 
Published: October 2008

Abstract
The Water Framework Directive (WFD) of the European Union requires member states to attain a good ecological status for all water bodies by the year 2015. This implies that the bioecological protection endpoint itself is upfront, next to abiotic chemical quality standards, as tools to protect those endpoints. Within the requirements of the Directive, ecological status and abiotic conditions will be monitored extensively. Based on the analysis of the monitoring data, authorities are required to derive Programs of Measures (PoMs) for impacted sites. Optimization of these programs requires diagnosis, to provide site-specific or catchment-specific information on the causes of observed deviations from a good ecological status. This article shows one pilot analysis of monitoring data (Scheldt River, Belgium) compiled in the scope of the EU MODELKEY project. Ecological, ecotoxicological, and statistical models are combined to quantify local ecological impact magnitudes and to identify site-specific factors that are associated with those impacts. Results show significant ecological effects in terms of taxa loss at study sites, which are highly variable among sites, with variable combinations of environmental factors associated with those effects. The results of the diagnostic approach are discussed, which appear to be complementary to the assessment of chemical status required by the Directive. Both types of assessment are useful to assist in the derivation of optimized PoMs. In addition, it could be concluded that the acute toxic pressure parameter relates to reduced taxon abundance for more than half of the studied taxa and that this parameter relates to the fraction of taxa lost under field conditions. Finally, various lessons for the execution of monitoring programs are derived because the Scheldt (bio)monitoring data set has its weaknesses, although it can be seen as typical for current monitoring programs.
Flood risk assessment in european river basins—concept, methods, and challenges exemplified at the mulde river
Authors: Meyer Volker , Haase Dagmar , Scheuer Sebastian 
Published: October 2008

Abstract
Flood risk assessment is an essential part of flood risk management, a concept that is becoming more and more popular in European flood policy and is part of the new European Union flood directive. This paper gives a brief introduction into the general concept and methods of flood risk assessment. Furthermore, 3 problems in the practical application of flood risk assessment, particularly on the river basin scale, are discussed: First, uncertainties in flood risk assessment; second, the inclusion of social and environmental flood risk factors; and third, the consideration of the spatial dimension of flood risk. In the 2nd part of the paper a multicriteria risk mapping approach is introduced that is intended to address these 3 problems.
Hydraulic-Fracture Production Forecast in Tight-Gas Reservoirs Using Wireline Formation Testers
Authors: van Galen M. , Peterson G. , Lorincz C. 
Published: October 2008

Abstract
By using pressure and fluid indetification data gathered with pump-out wireline formation testers, operators can gain a better understanding of the reservoir, resulting in quality decisions concerning the economic feasibility of stimulating particular zones with hydraulic fractures. Permeabilities and extrapolated reservoir pressures are calculated by performing pressure transient analysis (PTA) on the gathered data. These key parameters can be combined with parameters estimated from petrophysical logs and/or correlations from neighboring wells, resulting in a production forecast for the effectiveness of a potential hydraulic fracture. Input parameters for this hydraulic fracture model can be varied to generate multiple scenario production forecasts. Based on these forecasts, a well-informed decision can be made on whether or not to stimulate a zone with a hydraulic fracture. The pressure tests are performed in cased-hole environments where zones can be isolated with a dual packer tool assembly after perforating. With the pump-out capability of this tool, multiple drawdown and buildup cycles are performed.
Reconciling Production Decline with Reservoir Connectivity: Field Study
Authors: Khasanov M. , Krasnov V. , Petrov A. , Kelkar M. , Bahar A. 
Published: October 2008

Abstract
In Priobskaya Field, one of the largest operated oil fields in Central Siberia, the production data from each well are gathered on a daily basis. In addition, well tests are conducted periodically to determine the efficacy of the fracture (every well is hydraulically fractured) as well as the near well bore permeability value. The field is under water flood, and as a result, the average pressure is above bubble point.
While analyzing the long term production data, it was observed that the declining production period is much longer than what is expected of a field producing above bubble point and is supported by injected water. This discrepancy was explained by using higher value of oil compressibility, although no lab evidence indicated that such compressibility exists. With the help of high value of oil compressibility, the long decline can be reproduced.
In this study, we investigated the reasons for long term decline by considering the connectivity of sands in the reservoir. We examined the fine scale models with the upscaled models and noticed that the connectivity of sands is substantially changed during the upscaling process. When a fine scale model is generated, lack of connectivity between injectors and producers resulted in some of the sands being depleted as if producing under solution gas drive mechanism. Depending on the connectivity between the injector and producer, the production from a well was a result of combination of water support and solution gas drive. The GOR of a producer well is affected as well as the decline in production. When the reservoir model is upscaled, the production decline is no longer observed due to enhanced connectivity between injector and producer. Under those conditions, the only way to match the reservoir performance is by using high oil compressibility.
The improved understanding of the relationship between fine scale connectivity and the flow behavior is very helpful in future reservoir management strategy. By observing producing gas oil ratios and relative declines, the operator would be able to determine the relative connectivity of sands between the injectors and producers. This would help re-assign injection volumes as well as potential locations of new producers and injectors
Real-Time Connectivity and the Potential Benefits to Appalachian Operations
Authors: Dwyer J. P. , Chmela W. , Lamborn R. K. , Colomb C. L. , Quinn T. H. 
Published: October 2008

Abstract
New advanced technologies are being introduced into unconventional resource basins at a record setting pace. As these new technologies are being implemented, connectivity - communication between the office and the rigsite - becomes increasingly important to the operator both in support of these technologies and for improving business efficiency. The benefits of officeto-rig connectivity are found in many places: rig de-manning, personnel development, multi-vendor data management, global support infrastructure, declining subject matter expertise, real-time decision making and remote control to name a few.
This paper will first provide a summary of new connectivity technologies and how they have developed into their current technical and commercial state. Next, the paper will explore the commercial drivers for new connectivity technologies and the potential for their application in the eastern basins of the United States. Examples are provided of improved operational and business performance as a result of applying these connectivity technologies. Finally, the paper will clear up some myths regarding the cost of implementation of leading edge connectivity technologies and make a business case for adopting the "right level" of connectivity to make operations more efficient.
Towards a Characteristic Equation for Permeability
Authors: Siddiqui A. A. , Ilk D. , Blasingame T. A. 
Published: October 2008

Abstract
The characterization of reservoir permeability (k) remains the elusive challenge in reservoir engineering. This work considers prior developments in an evolutionary sense, and, as with prior work, our goal is the development of a "characteristic permeability relation" (CPR). To this end, we have developed 5 CPR formulations — 3 of which could be considered modifications of "historical" models and 2 of which are "weighted" power law-exponential models.
In this work, we consider permeability to be only a function of two variables; k = f(ϕ,z) — porosity (ϕ) and z. Where, for this work, z is either the water saturation (Sw) or the Archie Formation Factor (F). Our rationale in considering k = f(ϕ,z) is two fold — first, such a formulation is a fundamental extension of the k = f(ϕ) correlation work by Archie (and countless others); and second, our validation datasets are limited to literature cases and cases obtained from industry sources — none of which would be considered suitable for extension beyond porosity plus another variable.
We demonstrate and validate our concept of a characteristic permeability relation (CPR) using various datasets obtained from the literature and from industry sources. In this work we show that each proposed relation has a unique character and performance — depending on primarily on the data, rather than the functional form of the permeability relation. Using the characteristic permeability relations developed in this work — the proposed permeability relations can be extended to other and other data types. It may also be possible to develop so-called "hydraulic flow unit" methods which can be used to segregate petrophysical data into depositional flow sequences.
Prevention of Geochemical Scaling in Hydraulically Created Fractures: Laboratory and Field Studies
Authors: Nguyen P. , Weaver J. , Rickman R. 
Published: October 2008

Abstract
Fracture conductivity values observed by well testing following hydraulic fracture stimulation treatments are often much lower than the values obtained by laboratory measurements for most proppants. In addition, many stimulated wells show loss of fracture conductivity with time, leading to reduced productivity and lost revenue.
This rapid loss in fracture conductivity has been attributed to frac gel damage, embedment, proppant crushing, and fines invasion. All these damage mechanisms have been well studied in the laboratory, resulting in materials and methods employed to minimize their effect on conductivity. While these methods have improved productivity, stimulated wells rarely achieve the theoretical conductivity expected from a given proppant. In addition, fracture conductivity often declines continuously, suggesting that there are other factors that influence long-term fracture conductivity.
Recently it was suggested that a freshly placed proppant bed in a hot formation could undergo a geochemical process called diagenesis. This process involves the dissolution of some proppant minerals and subsequent reaction with minerals that are present in connate formation water. These subsequent reactions lead to the formation of many clays and clay-like crystals in addition to amorphous, porosity-filling materials that progressively damage the conductivity of propped fractures.
This paper presents (1) results of a laboratory study aimed at quantifying this damage mechanism, (2) the development of multiple strategies to minimize this damage mechanism, and (3) field case studies analyzing production data to support two of these laboratory-indicated strategies.
Findings reported in this paper should have a significant impact on how proppants are selected for various fracturing applications. To achieve maximum fracture conductivity and sustained production, it is no longer acceptable to simply select the proppants, based on API conductivity, cost, and availability, but planners must also consider (1) potential in situ reactions that may shorten proppant life or (2) proppant treatments that can be applied to minimize the impact of these reactions.
Case History of 8-lbm/gal Water-Based-Fluid Field Trial
Authors: Green T. C. , Minnett B. , Cremer J. 
Published: October 2008

Abstract
Drilling with less than normal pressure fracture gradients has led to the necessity, design and implementation of novel systems delivering equivalent mud weights from 4 to 8 pounds per gallon (ppg). These fluids are not light weight fluids like air or foam, but are not as dense as heavier conventional fluids. This combination of a small amount of equipment plus a novel water base fluid system has resulted in reduced pressures while drilling with a simple adjustment in air flow. These middle weight fluids have been field tested with a low pressure cavitation mixer, and minimal air supply, similar to what a rig air system supplies.
An inhibitive low solids fluid weighing 8.7 pounds per gallon (ppg) arrived at the standpipe at less than 8.0 ppg equivalent, due to the novel air injection system used between the pits and the rig pump. The fluid circulated through the standard triplex rig pump, then the air broke out just before the fluid flowed over the shaker screens, with no problems. Conventional solids control equipment was used without adjustment.
Just less than 8 pounds per gallon was maintained for several hours while drilling ahead horizontally. Brief periods of equivalent density as low as 5 pounds per gallon were possible, and can be reasonably expected after equipment changes are made. The wellbore remained slick and stable, hole cleaning was good. Standpipe pressure was approximately 400 pounds per square inch less (1600 pounds per square inch versus 2000 pounds per square inch) compared to conventional unaerated fluid.
The fluid formulation included a small amount of potassium formate, clay/shale stabilizers, xanthan gum and an air dispersant. Fluid chemistry facilitated even smooth air entrainment with instant breakout at surface. The formulation was solids free, with no intent to build a filter cake. While conventional solids control equipment was used to remove drill solids, supplementary solids control equipment was identified as necessary to extend the ability to maintain the equivalent density at less than 8 ppg.
The cavitation mixer injects air into the liquid under pressure, just before the fluid flows into the rig pump. The field trial began to identify air and liquid flow supply requirements for consistent middle weight densities.
Doxorubicin-transferrin conjugate selectively overcomes multidrug resistance in leukaemia cells
Authors: Łubgan Dorota , Jóźwiak Zofia , Grabenbauer Gerhard , Distel Luitpold 
Published: October 2008

AbstractNeoplastic cells frequently have an increased number of transferrin receptors. Coupling transferrin to an anti-neoplastic drug has the potential to overcome multidrug resistance (MDR). The purpose of this study was to examine the distribution and action of doxorubicin-transferrin conjugate (DOXTRF) in a leukaemia cell line (HL60), a multidrug-resistant leukaemia cell line (HL60ADR) and a normal tissue cell line (human fibroblasts). The intracellular accumulation of DOX and DOX-TRF was monitored by direct fluorescence. More DOX-TRF than free DOX was delivered to the tumour cells, and consecutively the levels of DNA double-strand breaks and apoptosis increased even in the multidrug-resistant cell line. In the normal tissue cell line, DOX-TRF did not accumulate, and therefore, the levels of DNA double-strand breaks and apoptosis did not increase. Cell viability was determined using the MTT assay. The IC50 for DOX-TRF was lower than the IC50 value for the free drug in both leukaemia cell lines. The IC50 values for the HL60 cells were 0.08 μM for DOX and 0.02 μM for DOX-TRF. The IC50 values for HL60ADR cells were 7 μM for DOX and 0.035 μM for DOX-TRF. In conclusion, DOX-TRF was able to overcome MDR in the leukaemia cell lines while having only a very limited effect on normal tissue cells.
Health Care Aides' Struggle to Build and Maintain Relationships with Families in Complex Continuing Care Settings
Authors: McGilton Katherine S. , Guruge Sepali , Librado Ruby , Bloch Lois , Boscart Veronique 
Published: October 2008

RÉSUMÉLa recherche sur les relations entre les aides-soignants (AS) et les familles des clients est menée principalement dans le milieu des soins de longue durée, et elle offre peu de résultats sur la perception des AS. Sur la base des résultats d’une étude qualitative plus étendue à l'aide d’une méthode basée sur une théorie reposant sur les faits, le présent article traite des relations AS-famille dans le cadre de soins continus complexes (SCC). Des entrevues individuelles approfondies avec huit AS et un groupe de suivi avec les AS de trois établissements de SCC ont été analysées. l'établissement de relations avec les familles nécessitait «être présent pour eux et leurs parents», tout en maintenant des relations comprenant le fait d’avoir à «faire face à une déception». Parmi les facteurs influençant l'établissement et le maintien de relations AS-famille, il faut noter «avoir des membres d’un groupe de soutien», «avoir des ressources disponibles» et «établir une structure hiérarchique dans l'équipe des soins de santé». Les résultats soulignent l'importance de réduire l'unité et les facteurs organisationnels qui dérangent les relations AS-famille.