TiO2 nanotubes and mesoporous silica as containers in self-healing epoxy coatings

The potential of inorganic nanomaterials as reservoirs for healing agents is presented here. Mesoporous silica (SBA-15) and TiO2 nanotubes (TNTs) were synthesized. Both epoxy-encapsulated TiO2 nanotubes and amine-immobilized mesoporous silica were incorporated into epoxy and subsequently coated on a carbon steel substrate. The encapsulated TiO2 nanotubes was quantitatively estimated using a ‘dead pore ratio’ calculation. The morphology of the composite coating was studied in detail using transmission electron microscopic (TEM) analysis. The self-healing ability of the coating was monitored using electrochemical impedance spectroscopy (EIS); the coating recovered 57% of its anticorrosive property in 5 days. The self-healing of the scratch on the coating was monitored using Scanning Electron Microscopy (SEM). The results confirmed that the epoxy pre-polymer was slowly released into the crack. The released epoxy pre-polymer came into contact with the amine immobilized in mesoporous silica and cross-linked to heal the scratch.This paper was made possible by PDRA grant # PDRA1-1216-13014 from the Qatar National Research Fund (a member of Qatar Foundation)

Oral cancer stem cells drive tumourigenesis through activation of stromal fibroblasts

Background Cancer stem cells are responsible for tumour progression and chemoresistance. Fibroblasts surrounding a tumour also promote progression and fibroblast “activation” is an independent prognostic marker in oral cancer. Cancer stem cells may therefore promote tumourigenesis through communication with stromal fibroblasts. Methods Cancer stem cells were isolated from oral cancer cell lines by adherence to fibronectin or cisplatin resistance. Fibroblasts were exposed to conditioned medium from these cells, and the activation markers, alpha smooth muscle actin and interleukin‐6, were assessed using qPCR and immunofluorescence. Stem cell markers and smooth muscle actin were examined in oral cancer tissue using immunohistochemistry. Results Adherent and chemoresistant cells expressed increased levels of stem cell markers CD24, CD44 and CD29 compared with unsorted cells. Adherent cells exhibited lower growth rate, higher colony forming efficiency and increased cisplatin resistance than unsorted cells. Smooth muscle actin and Interleukin‐6 expression were increased in fibroblasts exposed to conditioned medium. In oral cancer tissue, there was a positive correlation between expression of αSMA and stem cell markers. Conclusions Adherence to fibronectin and chemoresistance isolates stem‐like cells that can activate fibroblasts, which together with a correlation between markers of both in vivo, provides a mechanism by which such cells drive tumourigenesis

Revisiting client roles and capabilities in construction procurement

The need to improve performance of procurement in construction has resulted in several structural changes and re-arrangements for the acquisition of the client’s development scheme. Much of these changes have focused on the contribution and roles played by parties other than the client to the delivery of projects. The role of the client during these changes has evolved from one of a passive fund provider to an increasingly active participant and hands-on management in some of the procurement arrangements. However, there is little evidence that these evolving roles have been met with a commensurate progress in project delivery performance for client organisations. There is evidence that lack of progress is hindering project performance. Simultaneously, research has so far given less attention to the changes in client’s roles over time. This does not only call for a clarification of contribution the client makes in delivery of projects, but also highlights the need to re-visit the client roles under different procurement systems, and at different project phases, including pre-construction, construction and operational. This paper presents a review of common procurement arrangements in the construction industry and the changing roles of the client’s organisation. The paper also explores the client’s role in each of these arrangements to establish what capabilities enable effective project delivery and performance. The identification of the capabilities is achieved by mapping client roles against procurement arrangements. The analysis of mapping exercise shows that the client has two types of capabilities for the delivery of every project: a primary capability required by all clients; and secondary one that is specific to a particular procurement case. The primary capability could serve as the minimum threshold for self-evaluation by client organisations

The changing role of the public client in construction procurement

The public sector obligation to improve the performance of construction procurement has resulted in several changes to the organisation, roles and systems adopted for development schemes. For example, a less than expected outturn performance of traditional arrangements and the increase demand for public services led to the adoption of integrated procurement systems. These changes have seen a transition of client’s role from merely a funder to an active player working collaboratively alongside the private sector (as service providers) at different periods over the last three decades. These changes were expected to improve construction procurement performance dramatically as they allow the clients to enhance their organisational capabilities by assigning major part of their roles to the private sector. However, the literature does not show that the procurement performance has improved as a result of the changes in the client organisation. While research continues to emphasise the importance of the client role in the construction procurement, so far limited attention has been given to the development of the client’s internal organisation for better procurement performance. This paper reports a comprehensive review of the role of the client in construction procurement identified by various researchers to establish the role that the client has been performing over the last three decades. This has been achieved by applying a chronological mapping method of materials published on the subject over the last three decades. The analysis indicates that there are critical elements within the client role which have been consistently addressed over the last three decades. In addition, there are elements which have emerged as a consequence of the shift towards integrated systems. An understanding of critical and emerging elements will allow the clients to identify the gap between the required and the existing capabilities within their organisations, and to assess their procurement arrangement

Content-Based Image Retrieval Hybrid Approach using Artificial Bee Colony and K-means Algorithms

In this paper, a new clustering method is proposed for CBIR system; this method depends on combining ABC and k-means algorithm. Four features are used with the proposed method to retrieve the images. These features are extracted by: color histogram of HSV image and color histogram of opponent image to describe the color, Gabor filters and Ranklet transform for RGB image to describe the texture. The proposed hybrid clustering method is a clustering process for database of each feature using k-means algorithm enhanced by ABC algorithm. The innovation in this approach is that each solution in ABC algorithm represents the centroids of clusters that come out from applying k-means algorithm. The proposed method is applied on Wang dataset (1000 images in 10 classes) and evaluated by comparing the test results of the proposed scheme with another existing method uses same database. The results proved that the proposed method is superior to the existing method in terms of the precision in 6 out of 10 categories of WANG dataset, such that the average of the precisions for all categories is 0.8093

Elastic net penalized Quantile Regression Model and Empirical Mode Decomposition for Improving the Accuracy of the Model Selection

In quantile regression models, numerous penalization methods have been developed to deal with ordinary least-squares method problems. Such methods are ridge penalized quantile regression, lasso penalized quantile regression, and elastic net penalized quantile regression which are used for variable selection and regularization and deals with the multicollinearity problem when it exists between the predictor variables. However, the variables of interest are often represented through time series processes, in which such time series data are often non-stationary and non-linear, which leads to poor accuracy of the resultant regression models and hence results with less reliability. The EMD-EnetQR method is proposed to address this issue, which consists of applying the empirical mode decomposition (EMD) algorithm to time series data and then using the resulting components in penalized quantile regression models. This study aims to apply the proposed EMD-QREnet method to determine the influence of the decomposition components of the original time series predictor variables on the response variable to build a model fit and improve prediction accuracy. Furthermore, this study addressed the multicollinearity between the decomposition components. Simulation studies and real dataset applications were conducted. The results show that the proposed EMDQREnet method, in most cases, outperforms the other methods by improving prediction accuracy

Anti-inflammatory and anti-oxidant properties of Ipomoea nil (Linn.) Roth significantly alleviates cigarette smoke (CS)-induced acute lung injury via possibly inhibiting the NF-κB pathway

Acute respiratory distress syndrome (ARDS), a serious manifestation of acute lung injury (ALI), is a debilitating inflammatory lung disease that is caused by multiple risk factors. One of the primary causes that can lead to ALI/ARDS is cigarette smoke (CS) and its primary mode of action is via oxidative stress. Despite extensive research, no appropriate therapy is currently available to treat ALI/ARDS, which means there is a dire need for new potential approaches. In our study we explored the protective effects of 70 % methanolic-aqueous extract of Ipomoea nil (Linn.) Roth, named as In.Mcx against CS-induced ALI mice models and RAW 264.7 macrophages because Ipomoea nil has traditionally been used to treat breathing irregularities. Male Swiss albino mice (20–25 ± 2 g) were subjected to CS for 10 uninterrupted days in order to establish CS-induced ALI murine models. Dexamethasone (1 mg/kg), In.Mcx (100 200, and 300 mg/kg) and normal saline (10 mL/kg) were given to respective animal groups, 1 h before CS-exposure. 24 h after the last CS exposure, the lungs and bronchoalveolar lavage fluid (BALF) of all euthanized mice were harvested. Altered alveolar integrity and elevated lung weight-coefficient, total inflammatory cells, oxidative stress, expression of pro-inflammatory cytokines (IL-1β and IL-6) and chemokines (KC) were significantly decreased by In.Mcx in CS-exposed mice. In.Mcx also revealed significant lowering IL-1β, IL-6 and KC expression in CSE (4 %)-activated RAW 264.7 macrophage. Additionally, In.Mcx showed marked enzyme inhibition activity against Acetylcholinesterase, Butyrylcholinesterase and Lipoxygenase. Importantly, In.Mcx dose-dependently and remarkably suppressed the CS-induced oxidative stress via not only reducing the MPO, TOS and MDA content but also improving TAC production in the lungs. Accordingly, HPLC analysis revealed the presence of many important antioxidant components. Finally, In.Mcx showed a marked decrease in the NF-κB expression both in in vivo and in vitro models. Our findings suggest that In.Mcx has positive therapeutic effects against CS-induced ALI via suppressing uncontrolled inflammatory response, oxidative stress, lipoxygenase and NF-κB p65 pathway

Transforming the Capabilities of Artificial Intelligence in GCC Financial Sector: A Systematic Literature Review

Identity and access management is a business process framework that makes it easier to maintain genuine user identities and regulate access to sensitive assets. The word "access control"refers to an organization's policy for authorizing access procedures, the mechanisms that implement and enforce the policy, and the model that the policy and procedures are built on. Adopting new technology may give rise to specific cyber threats that decrease or degrade business operations. The paper has designed to discuss the artificial intelligence-based access control system as a necessary component of governing and safeguarding the financial sector's information assets in the Gulf Cooperation Council (GCC) region. Due to the dynamic and complicated nature of security rules for access control, organizations that employ web-enabled remote access in conjunction with applications access deployed over several networks face various obstacles, including increased operational complexity and monitoring concerns. Organizations spend a vast budget on securing their business. As the industry trend has shifted to intelligent internet-based companies on the same side, the cyber threat has become a challenge for the researcher to find the solution. A systematic research is conducted to fill the gaps in the existing literature by picking the most relevant research papers (126) from the four most reputable online repositories based on the four research questions specified. These research topics aim to evaluate the current situation from many perspectives and provide new avenues for future study to be studied soon to maintain high security and authenticity inside financial sectors of the GCC's countries

Investigation of Changing Pore Topology and Porosity during Matrix Acidizing using Different Chelating Agents

Core flooding acidizing experiments on sandstone/carbonate formation are usually performed in the laboratory to observe different physical phenomena and to design acidizing stimulation jobs for the field. During the tests, some key parameters are analyzed such as pore volume required for breakthrough as well as pressure. Hydrochloric acid (HCl) is commonly used in the carbonate matrix acidizing while Mud acid (HF: HCl) is usually applied during the sandstone acidizing to remove damage around the well bore. However, many problems are associated with the application of these acids, such as fast reaction, corrosion and incompatibility of HCl with some minerals (illite). To overcome these problems, chelating agents (HEDTA, EDTA and GLDA) were used in this research. Colton tight sandstone and Guelph Dolomite core samples were used in this study. The experiments usually are defined in terms of porosity, permeability, dissolution and pore topology. Effluent samples were analyzed to determine dissolved iron, sodium, potassium, calcium and other positive ions using Inductively Coupled Plasma (ICP). Meanwhile Nuclear Magnetic Resonance (NMR) was employed to determine porosity and pore structure of the core sample. Core flood experiments on Berea sandstone cores and dolomite samples with dimensions of 1.5 in × 3 in were conducted at a flow rate of 1 cc/min under 150oF temperature. NMR and porosity analysis concluded that applied chemicals are effective in creating fresh pore spaces. ICP analysis concluded that HEDTA showed good ability to chelate calcium, sodium, magnesium, potassium and iron. It can be established from the analysis that HEDTA can increase more amount of permeability as compared to other chelates

Complete genome sequence of Mycobacterium vaccae type strain ATCC 25954

Item does not contain fulltextMycobacterium vaccae is a rapidly growing, nontuberculous Mycobacterium species that is generally not considered a human pathogen and is of major pharmaceutical interest as an immunotherapeutic agent. We report here the annotated genome sequence of the M. vaccae type strain, ATCC 25954.1 november 201