National Research Center of Egypt

Cairo, Egypt

National Research Center of Egypt

Cairo, Egypt
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Abdel-Salam O.M.E.,National Research Center of Egypt
CNS and Neurological Disorders - Drug Targets | Year: 2011

Alzheimer's disease (AD) is a progressive neurodegenerative disorder which impairs the memory and intellectual abilities ofthe affected individuals. Loss of episodic as well as semantic memory is an early and principal feature. The basal forebrain cholinergic system is the population of neurons most affected by the neurodegenerative process. Extra cellular as well as intracellular deposition of β-amyloid or A beta (Aβ) protein, intracellular formation of neurofibrillary tangles and neuronal loss are the neuropathological hallmarks of AD. In the last few years, hopes were raised that cell replacement therapy would provide cure by compensating the lost neuronal systems. Stem cells obtained from embryonic as well as adult tissue and grafted into the intact brain of mice or rats were mostly followed by their in corporation into the host parenchyma and differentiation into functional neural lineages. In the lesioned brain, stem cells exhibited targeted migration towards the damaged regions of the brain, where they engrafted, proliferated and matured into functional neurones. Neural precursor cells can be intravenously administered and yet migrate into brain damaged areas and induce functional recovery. Observations in animal models of AD have provided evidence that transplanted stem cells or neural precursor cells (NPCs) survive, migrate, and differentiate into cholinergic neurons, astrocytes, and oligodendrocytes with amelioration of the learning/memory deficits. Besides replacement of lost or damaged cells, stem cells stimulate endogenous neural precursors, enhance structural neuro plasticity, and down regulate pro-inflammatory cytokines and neuronal apoptotic death. Stem cells could also be genetically modified to express growth factors into the brain. In the last years, evidence indicated that the adult brain of mammals preserves the capacity to generate new neurons from neural stem/progenitor cells. Inefficient adult neuro genesis may contribute to the pathogenesis of AD and other neuro degenerative disorders. An attempt at mobilizing this endogenous pool of resident stem-like cells provides another attractive approach for the treatment of AD. Studies in patients with AD indicated decreased hippocampal volume derived by neuro degeneration. Intriguingly, manydrugs including antidepressants, lithium, acetyl cholinesterase inhibitors, and ginkgo biloba, were able to enhance the impaired neurogenesis in this disease process. This paved the way towards exploring the possible pharmacological manipulation of neurogenesis which would offer an alternative approach for the treatment of AD. © 2011 Bentham Science Publishers.


Abdel-Salam O.M.E.,National Research Center of Egypt
CNS and Neurological Disorders - Drug Targets | Year: 2014

Parkinson’s disease (PD) is a neurodegenerative disorder, which results from the loss of specific population of neurons, namely the pigmented dopamine secreting neurons of the substnatia nigra pars compatica (SNPc) of midbrain. The exact cause leading to nigrostriatal cell death is not yet known. In recent years, accumulating evidence from the identified molecular events in familial forms of PD contributed much to unraveling the mechanisms by which dopaminergic neurons die in PD and which hopefully would lead to the development of therapeutic interventions. Several major disease causing pathways were identified so far. These are possibly interconnected and some genes share a common pathway e.g., (i) defects in ubiquitin-proteasome pathway and protein misfolding and aggregation caused by α-synuclein and Parkin gene defects; (ii) defects in mitochondrial morphology and function in PINK1/Parkin and DJ-1 mutations; (iii) increased susceptibility to cellular oxidative stress which appear to underlie defects in α-synuclein, Parkin and DJ-1 genes. The aim of this review is to shed light on the molecular mechanisms by which mutations in familial-linked genes cause PD. © 2014 Bentham Science Publishers.


Ibrahim M.E.,National Research Center of Egypt
International Journal of PharmTech Research | Year: 2016

As a part of an intensive screening program to introduce new source of essential oils (EO) to Egyptian industry, we aimed to evaluate the essential oils content of Verbena triphylla L leaves under the conditions of Egypt, Using two different extraction methods; hydro-distillation (HD) and solvent extraction (SE) to conclude whether of them is more efficient for producing high oil percentage with desirable composition. The plant materials were collected from fresh leaves and twigs of Verbena triphylla L shrub at full blooming stage. Maximum oil percentage was obtained with HD method compared with SE method. The components of essential oils isolated from leaves and twigs of Verbena triphylla L were identified by GC and GC-MS. The essential oil extracted either by water distillation or organic solvent contains the same main components Twenty five compounds were identified in the oil isolated by both methods, they represent approximately 95.69 % and 74.17 % for HD and SE extraction methods respectively. Citral (a+b) (23.25 %) is the major constituents in the oil isolated by DH method followed by D-limonene (16.11%), 1,8 Cineol (8.56%), Caryophyllen oxide (5.1%) and B-Citronellol (5.52%), while in absolute oil extracted from concrete, Citral (a+b) is the main constituent (28.34%) followed by B-Citronellol (9.32%) and Benzene, 1-(1.5 dimethyl1-4-hexenyl)-4-methyl- (5.3%). © 2016, Sphinx Knowledge House. All rights reserved.


Nanotechnology is one of the most active research areas with both novel science and useful applications that has gradually established itself in the last two decades. Nanoparticles belong to be prospective materials in the field of civil engineering. Some researchers have employed nanoparticles into cementitious materials-based on Portland cement (PC) aiming to modify some properties of this system. This paper presents an overview of the previous works carried out on the effect of using nano-Al2O3, nano-Fe2O3, nano-Fe3O4 and nano-clay into the cementitious materials. Some properties of the modified composites as heat of hydration, workability, setting time, mechanical strength, water absorption and durability were reviewed. This overview can be used as a short guide for Civil Engineer. © 2013 Elsevier Ltd.


Rashad A.M.,National Research Center of Egypt
Construction and Building Materials | Year: 2013

The development of new binders, as an alternative to Portland cement (PC), by alkaline activation, is a current researchers interest. Alkali-activated metakaolin (AAMK), belongs to prospective materials in the field of Civil Engineering. This paper presents a comprehensive overview of the previous works carried out on the use of MK in alkali activation. © 2013 Elsevier Ltd. All rights reserved.


Rashad A.M.,National Research Center of Egypt
Construction and Building Materials | Year: 2013

Kaolin can satisfy the world demand for filler, paper and ceramic industries. Kaolin converts to a pozzolan material named metakaolin (MK) after suitable thermal treatment. MK can be used in mortar and concrete to improve their properties. In addition, MK can be used as a source of cementing materials in alkali activation or geopolymer. This part presents a comprehensive overview of the previous works carried out on kaolin history, MK sources, production and composition. © 2012 Elsevier Ltd. All rights reserved.


Youssef A.M.,National Research Center of Egypt
Polymer - Plastics Technology and Engineering | Year: 2013

Polymer nanocomposites markedly improved packaging properties due to their nanometer size dispersion. These enhancements include increased modulus and strength, decreased gas permeability, and increased water resistance. Additionally, biologically active ingredients can be added to impart the desired functional properties to the resulting packaging materials. Accordingly, polymer-based nanocomposites packaging materials with bio-functional properties have a huge potential for application in the active food packaging industry. In this review, recent advances in the preparation and characterization of polymer nanocomposites, and their potential use in packaging applications are addressed. © 2013 Copyright Taylor and Francis Group, LLC.


The development of new binders, as an alternative to Portland cement (PC), by alkaline activation, is a current researchers interest. Alkali-activated fly ash (AAFA) binder is obtained by a manufacturing process less energy-intensive than PC and involves lower greenhouse gasses emission. Utilizing AAFA system as binder material can limit the consumption of virgin materials (limestone and sand) required in PC manufacture. AAFA belongs to be prospective material in the field of Civil Engineering where it can resist aggressive acids, resist sulfate attacks, resist aggregate alkali reaction, and resist elevated temperatures. Researchers have employed different fibers, chemical admixtures, mineral admixtures, additives and other materials in AAFA system aiming to modify special properties of this system. This paper presents a comprehensive overview of the previous works carried out on using different admixtures and additives in AAFA system. © 2013 Elsevier Ltd.


Rashad A.M.,National Research Center of Egypt
Construction and Building Materials | Year: 2014

Application of nano-SiO2 (NS) in cementitious materials has drawn much attention, due to the increased demand for new materials with attractive properties. Traditional cementitious materials based on Portland cement (PC) and alkali-activated fly ash (AAFA) systems were improved by applying NS aiming to develop a novel, smart and environment. This paper presents an overview of the previous works carried out on using NS into the traditional cementitious materials based on PC and AAFA. Heat of hydration, workability, setting time, strength, abrasion resistance, freeze-thaw resistance, fire resistance, drying shrinkage, resistance to aggressive environmental, leaching, water absorption, chloride penetration and permeability of PC-based materials modified with NS as well as comparison between NS and other nano types have been reviewed. In addition, previous works curried out on setting time, compressive strength and permeability of AAFA-based materials modified with NS have been reviewed. © 2013 Elsevier Ltd. All rights reserved.


Rashad A.M.,National Research Center of Egypt
Construction and Building Materials | Year: 2013

The development of new binders, as an alternative to Portland cement (PC), by alkaline activation, is a current researchers interest. Alkali-activated slag (AAS) binder is obtained by a manufacturing process less energy-intensive than PC and involves lower greenhouse gasses emission. AAS belongs to prospective materials in the field of Civil Engineering. Researchers have employed fibres, chemical admixtures, mineral admixtures and other materials as additives in AAS system aiming to modify some properties of this system. This paper presents a comprehensive overview of the previous works carried out on using different additives in AAS system. © 2013 Elsevier Ltd. All rights reserved.

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