MELK-a conserved kinase: functions, signaling, cancer, and controversy.

Maternal embryonic leucine zipper kinase (MELK) is a highly conserved serine/threonine kinase initially found to be expressed in a wide range of early embryonic cellular stages, and as a result has been implicated in embryogenesis and cell cycle control. Recent evidence has identified a broader spectrum of tissue expression pattern for this kinase than previously appreciated. MELK is expressed in several human cancers and stem cell populations. Unique spatial and temporal patterns of expression within these tissues suggest that MELK plays a prominent role in cell cycle control, cell proliferation, apoptosis, cell migration, cell renewal, embryogenesis, oncogenesis, and cancer treatment resistance and recurrence. These findings have important implications for our understanding of development, disease, and cancer therapeutics. Furthermore understanding MELK signaling may elucidate an added dimension of stem cell control

The Way I See It: Reflections of an Arab-American Journalist on the Middle East, Media and the State of Journalism

No audio/video recording exists.Ayman Mohyeldin is a Foreign Correspondent for NBC News based in Cairo. Prior to joining NBC, Ayman was a correspondent for Al Jazeera English based in Cairo where he was at the epicenter of Arab uprisings covering the revolutions in Tunisia and Egypt. From May 2008 until May 2010, Ayman was the only foreign broadcast journalist based in the Gaza Strip. During the 2008/2009 War on Gaza, he was the only American journalist reporting live from Gaza. In 2011, Time Magazine named Ayman as one of the 100 Most Influential People in the World. For his reporting, Ayman has won a Peabody Award, the UK’s Cutting Edge Media Award and Argentina’s prestigious Perfil International Press Freedom Award. He has received multiple Emmy nominations throughout his career. Ayman was born in Cairo, Egypt but grew up in between the US and the Middle East.JournalismMiddle Eastern Studie

Management services as an aid to administrative reform in the Sudan public service

In this research study the experience of the management services function as an aid to administrative reform in the Sudan is examined. Particular attention is paid to the establishment of the departmental management services units (DMSUs), as institutional in-built organs for administrative reform in the public service. The focus of the study is on the problems which confronted the DMSU programme. Interviews with a number of high-ranking personnel such as the former President Ga'afar Mohamad Nimeiri, the former Ministers of Public Service and Administrative Reform and some Under-Secretaries, all formed an important part of the procedure to trace the development of the management services function in the Sudan. They also provided the opportunity to highlight important issues and problems associated with the subject Comparative material on the experience of other countries showed that successful implementation of management services function can not be achieved in neglect of social, cultural and other environmental considerations. The effectiveness and optimum utilisation of the DMSUs must be affected by such considerations. The general finding of the study is that the DMSU programme has had a rather uneasy development. It did not achieve the objectives which were envisaged. Recommendations for the revival and successful implementation of the DMSU programme are set out in chapter 5.This study consists of five chapters. Chapter one is divided into two parts. One part is about administrative reform: the concept, definitions and approaches; and die second part briefly covers, the wider structure of administrative reform in die Sudan. Chapter two is about the experience of management services function in the Sudan. Chapter three is about the management services training courses and training of the management services officers locally and abroad. Chapter four covers analysis of the problems confronted in the management services in Sudan, and chapter five consists of the conclusion and recommendations

Functional nanostructred photoanodes for solar fuel production

Improving the efficiency of water splitting process is one of the main obstacles that are facing the generation of renewable energy. Charge carriers separation is always coupled with low visible light absorption and stability of the materials used. Various efforts have been done in order to construct a full system of different materials that can absorb visible light efficiently, with an enhanced electron hole separation process for an efficient water splitting. However, most of the reported systems suffer either from crystal mismatch between the multiple materials the use of long linkers that promote the recombination of the carriers. In this thesis, we are introduce a new system of titania nanotubes that are functionalized with graphene quantum dot, as a photosensitizer and an efficient charge carrier collector and transporter. In the first part of the thesis, one-dimensional TiO2 nanotubes photoanodes were investigated. We are able to produce ultra thin walled titania nanotubes, for the first time. Thin walled titania nanotubes showed higher quantum efficiency; about 50% compared to 15 % for conventional thick-walled nanotubes, with a 50% enhancement in the photocurrent. This enhancement is mainly attributed to the very small wall thickness (3 nm), allowing the diffusion of the charge carriers across the wall, regardless the potential across the region. In the second part, the effect of hydrogen annealing on the optical and electrical properties of the thin-walled nanotubes was investigated. It was found hydrogen annealing for 4 hours passivate the trap states on the surface of titania, while annealing for longer times acts to create more defect states, larger carrier concentration, larger dark current, higher resistance. In addition, we introduced a new concept by adding KOH and hydrogen annealing resulted in lower resistance and higher charge carrier concentration and photocurrent. In the third part, we produced graphene quantum dots, and for the first time, we were able to functionalize graphene quantum dots with different groups (mercapto propanoic acid, and malonyl group). We also introduced a new anchoring method for graphene quantum dots on the surface of titania. The photocurrent was enhanced by 50%, and the reasons were discussed in details. Finally, we showed the possible new applications for titania nanotubes that are functionalized with our graphene quantum dots

Investigation of the Physical and Molecular Properties of Asphalt Binders Processed with Used Motor Oils

In this work we investigated the performance aspects of addition of used motor oils (UMO) to neat and crumb rubber modified asphalts (CRMA) and related that to the change of molecular size distribution of modified asphalt’s fractions; asphaltenes, saturates, naphthene aromatics, and polar aromatics. Based on the results of temperature sweep viscoelastic tests, addition of crumb rubber modifier (CRM) alone or with UMO results in the formation of internal network within the modified asphalt. Based on the results of short and long term aged asphalts, the utilization of combination of UMO and CRM enhanced the aging behavior of asphalt. Bending beam rheometer was utilized to investigate the low temperature behavior of UMO modified asphalts. Based on those tests, the utilization of the UMO and CRM enhanced the low temperature properties of asphalts. Based on the results of the asphalt separation tests and the Gel Permeation Chromatography (GPC) analysis, it was found that saturates and naphthene aromatics are the two asphalt fractions that have similar molecular size fractions as those of UMO. However, UMO only shifts the molecular sizes of saturates after interaction with asphalt. Results also show that polar aromatics pose higher molecular size structures than UMO

Enhancing the Crumb Rubber Modified Asphalt\u27s Storage Stability through the Control of its Internal Network Structure

The current research investigated the effect of the internal network structure developed in the crumb rubber modified asphalt (CRMA) on its storage stability. The authors investigated the influence of asphalt-crumb rubber modifier (CRM) interaction parameters (interaction time, interaction speed, and interaction temperature) on the development of the internal network structure in CRMA. The authors found that the existence of three dimensional (3D) network structures in the CRMA enhanced its storage stability. Fourier Transform Infrared (FTIR) Spectroscopy was utilized to determine the nature of CRM components responsible for the development of 3D network structure in the liquid phase of CRMA. This was achieved by monitoring the changes of the IR distinctive peaks in the CRMA liquid phase. Dissolution tests and thermo gravimetric analysis (TGA) were carried out on the extracted CRM after interaction with asphalt to determine the role of CRM dissolved amounts and released components on the development of 3D network structure in CRMA. The asphalt-CRM interaction parameters were found to be essential to induce the formation of the 3D network structure within the liquid phase of the CRMA through controlling the swelling, dissolution and release of CRM components into the asphalt liquid phase. The existence of 3D network structure in the CRMA had determinant impact on the enhancement of its storage stability

Effects of Interaction Conditions on Internal Network Structure of Crumb Rubber-Modified Asphalts

Investigation of the effect of interaction conditions on the development of the internal network structure of crumb rubber-modified asphalt (CRMA) was carried out. Enhancements in the CRMA physical properties, such as stiffness, expressed in the complex modulus (G*), and elasticity, expressed in the phase angle (δ), as a result of the development of three-dimensional (3-D) entangled network structure were achieved. These results came from controlling the interaction conditions of CRMA synthesis to regulate the crumb rubber-modified (CRM) components that were responsible for the formation of the 3-1) entangled network structure. Dissolution tests and thermogravimetric analysis (TGA) were performed on the extracted CRM particles after interaction with asphalt. A Fourier transform infrared (FTIR) spectroscopy investigation was performed on the liquid phase asphalt after separation of CRM. FTIR was used to investigate the state of the released CRM components, previously calculated by TGA, which were responsible for the formation of the 3-D network structure. Use of rheological, TGA, and FTIR tests confirmed that the enhancement of the CRMA\u27s G* and δ was dependent on the dissolution or release of CRM components under specific interaction conditions that led to the existence of a 3-1) network structure within the liquid phase of the CRMA. The development of the 3-D entangled network structure in CRMA was found to be attributable to the release of most of the CRM natural and synthetic rubber components under specific interaction conditions. Enhancements in the CRMA G* and δ provided improved rutting resistance and alleviated permanent deformation problems

Effect of Used Motor Oil on the Macro and Micromechanical Properties of Crumb Rubber Modified Asphalt

The need to be more environmentally conscious has recently shifted toward the forefront of society. With this new focus on environmentally responsible behavior comes the practice of using recycled materials in construction when possible. Used motor oil (UMO) is an example of waste materials that can be utilized in numerous applications to alleviate its environmental disposal burden. In the current work, the effect of UMO on the internal structure of crumb rubber modified asphalt is investigated. This is carried out by employing rheological analysis including dynamic shear rheometer and microindentation testing. Rheological analysis was employed to determine the change in the phase angle (δ) as well as the complex modulus (G*) of the UMO modified asphalts as well as the crumb rubber modified asphalt (CRMA), in addition, temperature sweep viscoelastic analysis was employed to investigate the change in internal structure of the produced modified asphalts. Microindentation analysis was utilized to determine the hardness and elastic modulus of the modified asphalt liquid phase. Microindentation tests served to simulate the effect of UMO on the behavior of the thin asphalt layer over the aggregate which has a thickness measured in microns. Results indicate that the utilization of UMO only as a modifier to asphalt severely deteriorates the macro and micro mechanical properties of the binder. Combining CRM with UMO as modifiers to asphalt had better results. It is suggested to use UMO at a rate of 3%, or less, by asphalt weight

Performance Enhancement of Crumb Rubber-Modified Asphalts through Control of the Developed Internal Network Structure

Control of the internal network structure of crumb rubber-modified asphalt (CRMA) was investigated for its effect on property development in the study presented in this paper. The investigation included evaluation by rheological and interrupted shear tests. Rheological testing involved the monitoring of the changes of the produced complex modulus (G*) and phase angle (δ) for CRMA. In the interrupted shear tests, the shear stress profile for the produced CRMA was investigated. It was found that triggering the critical conditions of the combined interaction of speed, temperature, and time was essential to inducing the formation of the three-dimensional network structure within CRMA. Such triggering conditions played an important role in the swelling, dissolution, and release of crumb rubber modifier components into the asphalt liquid phase. Gel permeation chromatography was used to characterize the nature of modifications that led to the occurrence of a three-dimensional network structure within the produced CRMA. The formation of a three-dimensional network structure for CRMA played a major role in the enhancement of its rheological properties in terms of its stiffness and elasticity. Superior improvements in the stiffness and elasticity indicated improved rutting resistance as well as alleviated permanent deformation problems

Effect of Crumb Rubber Modifier Dissolution on Storage Stability of Crumb Rubber-Modified Asphalt

Crumb rubber-modified asphalt (CRMA) extensively suffers from high-temperature storage instability. Because of the higher density of the crumb rubber modifier (CRM) particles, they settle down to the bottom of storage tanks and cause variation between physical properties of the top and bottom samples. The storage stability of the CRMA changes under different interaction parameters and consequently different mechanisms of interaction. In this research the mechanism of separation under different levels of CRM dissolution was investigated by using Stokes\u27 law. The extent and mechanism of CRM dissolution in asphalt was controlled through regulating interaction temperature and interaction mixing speed. A standard storage stability test was conducted on CRMA samples to measure the corresponding storage stability index. Viscosity of the liquid phase of CRMA was measured at the same temperature as that of the storage stability test (163 C), with the use of a rotational visco-meter, to study the effect of viscosity development of the liquid phase on the storage stability of CRMA. Composition analysis was conducted by using thermogravimetric analysis to investigate the effect of changes in CRM composition on the storage stability of CRMA. Results reveal that, in addition to the CRM particle size reduction resulting from CRM dissolution, the viscosity development of the liquid phase affects the storage stability of CRMA with the interaction temperature of 190 C. But increasing the interaction temperature to 220 C changes the mechanism of dissolution and the nature of the residual CRM particles and consequently leads to a different mechanism of separation