The Effect of Rock Properties on Fracture Conductivity in the Marcellus Shale

Hydraulic fracturing is a stimulation technique that has made production from unconventional reservoirs such as shale formations economically feasible. This technique creates high conductivity paths that improve the communication between the reservoir and the wellbore. The success of this technique depends on the ability to fracture the rock and to maintain fracture conductivity. Therefore, in order to have a successful treatment, the effect of parameters such as formation properties, type of proppant and proppant concentration on fracture conductivity and fracture creation should be considered. This work investigates the relationship between fracture conductivity and formation properties for two different locations in the Marcellus shale. Multiple cores from the locations were collected to ensure repeatability in the results. The core samples were fractured parallel and perpendicular to the bedding planes in order to analyze the effect of anisotropy in fracture conductivity. Additionally, compressive triaxial tests were performed to obtain the rock mechanical properties in the elastic region until permanent deformation was reached, and X-ray Diffraction analysis was used to obtain mineralogy composition. The laboratory results were compared with previous fracture conductivity data and surface roughness data from the same Marcellus shale locations. The findings showed that the anisotropy effect is present for this formation and reflected in the fracture conductivity values, where samples parallel to the bedding plane seem to have higher Young’s Modulus. At proppant monolayer concentration the main mechanism for conductivity loss is proppant embedment, where due to the high localized stress, the rock-proppant interaction goes directly to permanent deformation of the rock. It was also observed that a higher Young’s Modulus helps to maintain the fracture width which translates in lower rate of conductivity loss with increasing closure stress. Rock mechanical properties have impact on fracture conductivity. This effect is less pronounced if a multilayer proppant concentration is used, where the proppant pack characteristics become an important parameter in fracture conductivity

Recent results on self-dual configurations on the torus

We review the recent progress on our understanding of self-dual SU(N) Yang-Mills configurations on the torus.Comment: Latex 3 pages, 1 figure. Contribution to the Lat99 Proceeding

Perturbative construction of self-dual configurations on the torus

We develop a perturbative expansion which allows the construction of non-abelian self-dual SU(2) Yang-Mills field configurations on the four-dimensional torus with topological charge 1/2. The expansion is performed around the constant field strength abelian solutions found by 't Hooft. Next to leading order calculations are compared with numerical results obtained with lattice gauge theory techniques.Comment: latex file. 32 pages and 4 figures(24 eps files

Conformational Flexibility of A Highly Conserved Helix Controls Cryptic Pocket Formation in FtsZ

Mycobacterium tuberculosis is responsible for more than 1.6 million deaths each year. One potential antibacterial target in M. tuberculosis is filamentous temperature sensitive protein Z (FtsZ), which is the bacterial homologue of mammalian tubulin, a validated cancer target. M. tuberculosis FtsZ function is essential, with its inhibition leading to arrest of cell division, elongation of the bacterial cell and eventual cell death. However, the development of potent inhibitors against FtsZ has been a challenge owing to the lack of structural information. Here we report multiple crystal structures of M. tuberculosis FtsZ in complex with a coumarin analogue. The 4-hydroxycoumarin binds exclusively to two novel cryptic pockets in nucleotide-free FtsZ, but not to the binary FtsZ-GTP or GDP complexes. Our findings provide a detailed understanding of the molecular basis for cryptic pocket formation, controlled by the conformational flexibility of the H7 helix, and thus reveal an important structural and mechanistic rationale for coumarin antibacterial activity

HQR-Scheme: A High Quality and resilient virtual primary key generation approach for watermarking relational data

Most of the watermarking techniques designed to protect relational data often use the Primary Key (PK) of relations to perform the watermark synchronization. Despite offering high confidence to the watermark detection, these approaches become useless if the PK can be erased or updated. A typical example is when an attacker wishes to use a stolen relation, unlinked to the rest of the database. In that case, the original values of the PK lose relevance, since they are not employed to check the referential integrity. Then, it is possible to erase or replace the PK, compromising the watermark detection with no need to perform the slightest modification on the rest of the data. To avoid the problems caused by the PK-dependency some schemes have been proposed to generate Virtual Primary Keys (VPK) used instead. Nevertheless, the quality of the watermark synchronized using VPKs is compromised due to the presence of duplicate values in the set of VPKs and the fragility of the VPK schemes against the elimination of attributes. In this paper, we introduce the metrics to allow precise measuring of the quality of the VPKs generated by any scheme without requiring to perform the watermark embedding. This way, time waste can be avoided in case of low-quality detection. We also analyze the main aspects to design the ideal VPK scheme, seeking the generation of high-quality VPK sets adding robustness to the process. Finally, a new scheme is presented along with the experiments carried out to validate and compare the results with the rest of the schemes proposed in the literature

A Double Fragmentation Approach for Improving Virtual Primary Key-Based Watermark Synchronization

Relational data watermarking techniques using virtual primary key schemes try to avoid compromising watermark detection due to the deletion or replacement of the relation's primary key. Nevertheless, these techniques face the limitations that bring high redundancy of the generated set of virtual primary keys, which often compromises the quality of the embedded watermark. As a solution to this problem, this paper proposes double fragmentation of the watermark by using the existing redundancy in the set of virtual primary keys. This way, we guarantee the right identification of the watermark despite the deletion of any of the attributes of the relation. The experiments carried out to validate our proposal show an increment between 81.04% and 99.05% of detected marks with respect to previous solutions found in the literature. Furthermore, we found out that our approach takes advantage of the redundancy present in the set of virtual primary keys. Concerning the computational complexity of the solution, we performed a set of scalability tests that show the linear behavior of our approach with respect to the processes runtime and the number of tuples involved, making it feasible to use no matter the amount of data to be protected

Autohydrolysis followed by ionic liquid treatment for Eucalyptus globulus wood fractionation

The 2030 Agenda for Sustainable Development recognises the need for a green and sustainable chemistry and engineering [1]. In this context, cleaner processes require the substitution of organic solvents by less harmful solvents. In addition, the solvent selection for a biomass processing is crucial for the environmental sustainability and feasibility of a biorefinery [2]. In this work, water and the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) were chosen as green solvents for a selective fractionation of Eucalyptus globulus wood in order to valorise their main fractions (hemicellulose, cellulose and lignin). Two sequential stages were proposed for the biomass processing. First, an autohydrolysis step allowed the hemicellulose solubilisation and its recovery as oligosaccharides in the aqueous liquid phase, yielding a solid phase composed by 60 % glucan and 34 % lignin. Second, a treatment with [C2mim][OAc] was evaluated for the delignification of the autohydrolysed biomass. Optimisation of operational conditions (temperature and time) of the ionic liquid treatment was performed to improve the enzymatic saccharification of cellulose remaining in the solid phase and to solubilise lignin. The proposed process configuration is expected to contribute towards the development of integrated biorefineries based on hardwood biomass.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit, BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional doNorte, the EcoTech project (POCI01-0145-FEDER-032206). Aloia Romaní thanks the Iacobus Program (European Territorial Cooperation Partnership Galicia – Norte de Portugal) for a mobility fellowship.info:eu-repo/semantics/publishedVersio

P-Glycoprotein and Breast Cancer Resistance Protein in Canine Inflammatory and Noninflammatory Grade III Mammary Carcinomas

P-glycoprotein (P-gp/ABCB1) and breast cancer resistance protein (BCRP/ABCG2) expression are frequently related to multidrug resistance (MDR) in neoplastic cells. Canine inflammatory and grade III noninflammatory mammary carcinomas (IMC and non-IMC) are aggressive tumors that could benefit from chemotherapy. This study describes the immunohistochemical detection of P-gp and BCRP in 20 IMCs and 18 non-IMCs from dogs that had not received chemotherapy. Our aim was to determine if P-gp and BCRP expression was related to the \u201cinflammatory\u201d phenotype, to establish a basis for future studies analyzing the response to chemotherapy in dogs with highly malignant mammary cancer. Immunolabeling was primarily membranous for P-gp with a more intense labeling in emboli, and immunolabeling was membranous and cytoplasmic for BCRP. P-gp was expressed in 17 of 20 (85%) IMCs compared to 7 of 18 (39%) non-IMCs (P = 0.006). BCRP was expressed within emboli in 15 of 19 (79%) emboli in IMC, 12 of 15 (80%) primary IMCs, and 12 of 18 (67%) non-IMCs, without statistically significant differences (P >.05). All IMCs and 67% of non-IMCs expressed at least 1 of the 2 transporters, and 63% (12/19) of IMCs and 39% (7/18) of non-IMCs expressed both P-gp and BCRP. P-gp and BCRP evaluation might help select patients for chemotherapy. P-gp, expressed in a significantly higher percentage of IMCs vs non-IMCs, might play a specific role in the chemoresistance of IMC