Fractionation of Asphaltenes in Understanding Their Role in Petroleum Emulsion Stability and Fouling

SARA fractionation separates crude oil into fractions of saturates (S), aromatics (A), resins (R), and asphaltenes (A) based on the differences in their polarizability and polarity. Defined as a solubility class, asphaltenes are normally considered as a nuisance in the petroleum industry mainly as a result of their problematic precipitation and adsorption at oil–water and oil–solid interfaces. Because a broad range of molecules fall within the group of asphaltenes with distinct sizes and structures, considering the asphaltenes as a whole was noted to limit the deep understanding of governing mechanisms in asphaltene-induced problems. Extended-SARA (E-SARA) is proposed as a concept of asphaltene fractionation according to their interfacial activities and adsorption characteristics, providing critical information to correlate specific functional groups with certain characteristics of asphaltene aggregation, precipitation, and adsorption. Such knowledge is essential to addressing asphaltene-related problems by targeting specific subfractions of asphaltenes

Multiplex amplification of all coding sequences within 10 cancer genes by Gene-Collector

Herein we present Gene-Collector, a method for multiplex amplification of nucleic acids. The procedure has been employed to successfully amplify the coding sequence of 10 human cancer genes in one assay with uniform abundance of the final products. Amplification is initiated by a multiplex PCR in this case with 170 primer pairs. Each PCR product is then specifically circularized by ligation on a Collector probe capable of juxtapositioning only the perfectly matched cognate primer pairs. Any amplification artifacts typically associated with multiplex PCR derived from the use of many primer pairs such as false amplicons, primer-dimers etc. are not circularized and degraded by exonuclease treatment. Circular DNA molecules are then further enriched by randomly primed rolling circle replication. Amplification was successful for 90% of the targeted amplicons as seen by hybridization to a custom resequencing DNA micro-array. Real-time quantitative PCR revealed that 96% of the amplification products were all within 4-fold of the average abundance. Gene-Collector has utility for numerous applications such as high throughput resequencing, SNP analyses, and pathogen detection

Alterations of the retinoblastoma gene in metastatic breast cancer

Germline mutations affecting the retinoblastoma gene (RB1) predispose to inherited retinoblastomas but also other malignancies, including breast cancer. While somatic RB1 mutations have been detected in different malignancies, information about the potential role of RB1 mutations in breast cancer is limited. Recently, we discovered RB1 mutations to be associated with resistance to anthracyclines/mitomycin in primary breast cancer. The present work is the first report evaluating RB1 mutation and epigenetic status in metastatic breast cancer. Among 148 breast cancer samples analyzed by MLPA, four samples harbored intragenic deletions/duplications: Thus, exons 1–2 were deleted in two tumors and exons 21–23 in one tumor, while one sample harbored duplication of exons 18–23. The entire RB1 gene was duplicated in two tumors and multiple amplifications were revealed in one sample. Reduced copy number was observed in 17 samples (11.5%). No point mutation or promoter hypermethylation was discovered (n = 38 and 114 tumors analyzed, respectively). Interestingly, among seven tumors expressing lack of response to epirubicin, two samples harbored alterations in RB1, contrasting none out of 16 tumors with stable disease or an objective response (P = 0.08). In summary, the frequency of RB1 alterations in metastatic lesions was not increased when compared to primary breast cancer, indicating that RB1 alterations do not play a major role in metastatic development. While a non-significant association suggesting RB1 alterations to be linked to therapy resistance was observed, our data do not suggest a major role for RB1 alterations explaining acquired drug resistance

Recurrent gross mutations of the PTEN tumor suppressor gene in breast cancers with deficient DSB repair

Basal-like breast cancer (BBC) is a subtype of breast cancer with poor prognosis. Inherited mutations of BRCA1, a cancer susceptibility gene involved in double-strand DNA break (DSB) repair, lead to breast cancers that are nearly always of the BBC subtype; however, the precise molecular lesions and oncogenic consequences of BRCA1 dysfunction are poorly understood. Here we show that heterozygous inactivation of the tumor suppressor gene Pten leads to the formation of basal-like mammary tumors in mice, and that loss of PTEN expression is significantly associated with the BBC subtype in human sporadic and BRCA1-associated hereditary breast cancers. In addition, we identify frequent gross PTEN mutations, involving intragenic chromosome breaks, inversions, deletions and micro copy number aberrations, specifically in BRCA1-deficient tumors. These data provide an example of a specific and recurrent oncogenic consequence of BRCA1-dependent dysfunction in DNA repair and provide insight into the pathogenesis of BBC with therapeutic implications. These findings also argue that obtaining an accurate census of genes mutated in cancer will require a systematic examination for gross gene rearrangements, particularly in tumors with deficient DSB repair

Problematic Stabilizing Films in Petroleum Emulsions: Shear Rheological Response of Viscoelastic Asphaltene Films and the Effect on Drop Coalescence

Adsorption of asphaltenes at the water-oil interface contributes to the stability of petroleum emulsions by forming a networked film that can hinder drop-drop coalescence. The interfacial microstructure can either be liquid-like or solid-like, depending on (i) initial bulk concentration of asphaltenes, (ii) interfacial aging time, and (iii) solvent aromaticity. Two techniques--interfacial shear rheology and integrated thin film drainage apparatus--provided equivalent interface aging conditions, enabling direct correlation of the interfacial rheology and droplet stability. The shear rheological properties of the asphaltene film were found to be critical to the stability of contacting drops. With a viscous dominant interfacial microstructure, the coalescence time for two drops in intimate contact was rapid, on the order of seconds. However, as the elastic contribution develops and the film microstructure begins to be dominated by elasticity, the two drops in contact do not coalescence. Such step-change transition in coalescence is thought to be related to the high shear yield stress (~10(4) Pa), which is a function of the film shear yield point and the film thickness (as measured by quartz crystal microbalance), and the increased elastic stiffness of the film that prevents mobility and rupture of the asphaltene film, which when in a solid-like state provides an energy barrier against drop coalescence

Encyclopedic Handbook of Emulsion Technolgy

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Three Industrial Cases of Sheet Metal Forming Simulations with Elastic Dies

Previous research and experience points to many advantages if sheet metal forming is simulated with elastic dies. Some areas that are enabled by simulations with elastic dies are virtual spotting, improved digital twins, and improved production support. A promising method was selected from the literature, and after important modifications it is deemed to be fast and robust for simulating industrial sized dies. The method consists of meshing die solids with a coarse mesh to represent the structural behaviour of the die. The forming surfaces are then represented by a fine shell mesh connected to the solid mesh by tied contacts with an offset. With additional modifications to reduce solver time this yields a robust and flexible way of modelling sheet metal forming with elastic dies. There is an increase in preprocessing and simulation time compared to using rigid tools, but industrial dies can now be modeled within an hour and solved within a working day. It is also easy to update the model by replacing separate parts such as die solids or forming surfaces. One of the main criteria in favor of the selected approach is the realistic modeling of blankholder and cushion systems. In this paper simulations of three industrial cases are demonstrated: one case of virtual die spotting and two cases of production support. The three cases demonstrate the importance and potential of using elastic dies during virtual die tryout, production support, and for cases like digital twins and production control.Eureka Smart Cambe

An overview of Methods for Simulating Sheet Metal Forming with Elastic Dies

Sheet metal forming (SMF) simulations are traditionally carried out with rigid active forming surfaces. This means that the elasticity and dynamics of presses and die structures are ignored. The only geometries of the tools included in the simulations are the active forming surfaces. One reason for this simplification is the large amount of computational power that is required to solve finite element (FE) models that incorporates elastic stamping dies. Another reason is the lack of die CAD models before the later stages of stamping projects. Research during the last couple of decades indicated potential large benefits when including elastic dies in SMF simulations. For example, for simulating die try-out or for Digital Twins of presses and dies. Even though the need and potential benefits of elastic dies in simulations are well known it is not yet implemented on a wide scale. The main obstacles have been lacking data on presses and dies, long simulation times, and no standardized implementation in SMF software. This paper presents an overview of existing methods for SMF simulations with elastic dies and discuss their respective benefits and drawbacks. The survey of methods shows that simulation models with elastic tools will be needed for detailed analyses of forming operations and also for purposes like digital twins. On the other hand, simplified and robust models can be developed for non-FEA users to carry out simple one-step compensation of tool surfaces for virtual spotting purposes. The most promising and versatile method from the literature is selected, modified, and demonstrated for industrial sized dies.Eureka Smart Cambe

RSC Adv.

Ionic liquids are assessed as chemical additives to modulate physical properties of oils. Rheometry, differential scanning calorimetry, thermogravimetric analysis and microscopy are used to investigate the effect of ionic liquids on oil properties. The measured maximum apparent viscosity value of Model Oil A increases by 178.7% in the presence of 1 wt% 1-butyl-3-methylimidazolium chloride. Similarly, the value increases in the presence of other conventional ionic liquids. However, the dispersed property of ILs in Model Oil A is not as good as expected. Thus, dispersant D-IL-202 is utilized to make ionic liquids dispersed completely in Model Oil A and form Model Oil B. The gel strength and maximum measured apparent viscosity of Model Oil B increase by 477.4%, 352.4% respectively in the presence of 1 wt% 1-butyl-3-methylimidazolium chloride. Wax crystals precipitate at temperature below wax appearance temperature. The melting point of 1-butyl-3-methylimidazolium chloride is higher than wax appearance temperature. Therefore, during the gelation process, the precipitated crystals of 1-butyl-3-methylimidazolium chloride may serve as nuclei and enhance wax crystal nucleation, precipitation and growth. In addition, the charges of 1-butyl-3-methylimidazolium chloride may make the precipitated wax crystals form a charge-stabilized colloids system. Thus, strong and stable crystal networks form during the gelation process. 1-Butyl-3-methylimidazolium chloride can be utilized as a wax promoter additive for wax separation from waxy oils in the oil industry. Thermogravimetric analysis shows 1-butyl-3-methylimidazolium chloride does not influence the decomposition temperatures of wax and asphaltene. However, the decomposition temperature of 1-butyl-3-methylimidazolium chloride increases in the presence of wax and decreases in the presence of asphaltene. Furthermore, micrographs results show 1-butyl-3-methylimidazolium chloride enhances wax precipitation to make long wax crystals form. In summary, the conventional ionic liquids used in this work can enhance the wax precipitation and/or stabilize the wax crystal networks. Thus, these ionic liquids can be utilized as a wax promoter additive for wax separation in the waxy oil industry. In addition, the property and function of ionic liquids can be designed and modified to be utilized as novel additives for oil properties modulation. Therefore, ionic liquids are promising environmentally friendly additives for the oil industry.Ionic liquids are assessed as chemical additives to modulate physical properties of oils. Rheometry, differential scanning calorimetry, thermogravimetric analysis and microscopy are used to investigate the effect of ionic liquids on oil properties. The measured maximum apparent viscosity value of Model Oil A increases by 178.7% in the presence of 1 wt% 1-butyl-3-methylimidazolium chloride. Similarly, the value increases in the presence of other conventional ionic liquids. However, the dispersed property of ILs in Model Oil A is not as good as expected. Thus, dispersant D-IL-202 is utilized to make ionic liquids dispersed completely in Model Oil A and form Model Oil B. The gel strength and maximum measured apparent viscosity of Model Oil B increase by 477.4%, 352.4% respectively in the presence of 1 wt% 1-butyl-3-methylimidazolium chloride. Wax crystals precipitate at temperature below wax appearance temperature. The melting point of 1-butyl-3-methylimidazolium chloride is higher than wax appearance temperature. Therefore, during the gelation process, the precipitated crystals of 1-butyl-3-methylimidazolium chloride may serve as nuclei and enhance wax crystal nucleation, precipitation and growth. In addition, the charges of 1-butyl-3-methylimidazolium chloride may make the precipitated wax crystals form a charge-stabilized colloids system. Thus, strong and stable crystal networks form during the gelation process. 1-Butyl-3-methylimidazolium chloride can be utilized as a wax promoter additive for wax separation from waxy oils in the oil industry. Thermogravimetric analysis shows 1-butyl-3-methylimidazolium chloride does not influence the decomposition temperatures of wax and asphaltene. However, the decomposition temperature of 1-butyl-3-methylimidazolium chloride increases in the presence of wax and decreases in the presence of asphaltene. Furthermore, micrographs results show 1-butyl-3-methylimidazolium chloride enhances wax precipitation to make long wax crystals form. In summary, the conventional ionic liquids used in this work can enhance the wax precipitation and/or stabilize the wax crystal networks. Thus, these ionic liquids can be utilized as a wax promoter additive for wax separation in the waxy oil industry. In addition, the property and function of ionic liquids can be designed and modified to be utilized as novel additives for oil properties modulation. Therefore, ionic liquids are promising environmentally friendly additives for the oil industry