Yaser Greish | UAE University (original) (raw)
Papers by Yaser Greish
Nanoscale Advances, 2022
An overview of the MOF-based gas sensing materials with different electrical transduction princip... more An overview of the MOF-based gas sensing materials with different electrical transduction principles.
Advances in Experimental Medicine and Biology
Biodegradable scaffolds are useful tools in the field of tissue engineering and regenerative medi... more Biodegradable scaffolds are useful tools in the field of tissue engineering and regenerative medicine. The aim of this study was to test the potential of the human stem cells of apical papilla (SCAP) to attach, proliferate and differentiate on a polycaprolactone (PCL)-based scaffolds. SCAP were extracted from the root apical papillae of freshly extracted immature premolar teeth by using enzymatic digestion. Porous PCL scaffolds were fabricated using particle leaching method and NaCl or mannitol as porogens. SCAP of passage 3 were seeded on non-porous and porous PCL scaffolds for up to 14 days. For control, cells were cultured on glass coverslips. Picogreen DNA quantification was used to assay for cell proliferation. Cell differentiation and development of calcification nodules were examined using scanning electron microscopy and alizarin red staining. SCAP showed a comparable attachment, growth and proliferation patterns on PCL scaffolds and coverslips. Cell proliferation was enhanced on mannitol scaffolds at all time points. Calcification nodules were detected in all PCL scaffolds while it was not present on glass coverslips. These nodules were detected on NaCl-scaffolds by day 7 and on mannitol and non-porous scaffolds by day 14. In conclusion, SCAP were able to attach, proliferate and differentiate on PCL scaffolds without using any inductive media, indicating their potential application for dental tissue regeneration.
Scaffolds in Tissue Engineering - Materials, Technologies and Clinical Applications, Dec 13, 2017
Tissue engineering has been viewed as a valid approach toward the partial or total replacement of... more Tissue engineering has been viewed as a valid approach toward the partial or total replacement of defective tissues and organs. Recent advances in nanotechnology have made it possible to develop biocompatible materials at the micro-and nano-scales to be used as scaffolds for cellular growth and regeneration of defective tissues. Gastric mucosal lining is an example of soft tissues that are highly susceptible to damage due to various reasons including cancer or ulcer development. Current therapeutic approaches to these diseases have some limitations. This chapter describes the basis for development of a novel modality combining nanotechnology, stem cells, and tissue engineering for the replacement of defective gastric tissues using synthetic biocompatible scaffolds. These microfibrous scaffolds are seeded with gastric stem cells, which are studied for their proliferation and differentiation into functional gastric mucous cells.
Journal of Biomaterials Science, Polymer Edition, 2011
Microporous and Mesoporous Materials, 2013
ABSTRACT Transition-metal-doped γ-alumina with various dopant concentrations was prepared by stra... more ABSTRACT Transition-metal-doped γ-alumina with various dopant concentrations was prepared by straightforward template-free sol–gel method. The presence of dopant metal ions, generally, enhanced the gel formation and their behavior was dependent on the nature of the metal ion and its concentration. Certain ions, especially Fe3+, resulted in rapid formation of a transparent gel upon hydrolysis. The prepared doped γ-alumina powders weakly crystalline at low dopant ion concentrations, 2%, and became completely amorphous at a concentration of 10%. The morphology of the particles was also dependent on the dopant concentration. While dopant concentration of 2% resulted in nano-particles with significant amount of inter-particle mesopores, 10% concentration led to significant aggregation into larger particles. The prepared doped γ-Al2O3 as well as the undoped γ-Al2O3 showed high surface areas and pore volumes which were largely dependent on the nature of the dopant metal ions and on their concentrations. While composites with low dopant concentration, 2%, exhibited surface areas and pore volumes comparable to those of undoped γ-alumina, a considerable decrease was associated with higher concentrations. The changes in textural properties were referred to the evident enhanced sintering associated with high dopant concentrations.
Journal of …, 2006
Page 1. Delivered by Ingenta to: ? IP : 93.91.26.12 Fri, 10 Dec 2010 14:04:20 RESEARCH AR TICLE C... more Page 1. Delivered by Ingenta to: ? IP : 93.91.26.12 Fri, 10 Dec 2010 14:04:20 RESEARCH AR TICLE Copyright © 2006 American Scientific Publishers All rights reserved Printed in the United States of America Journal of Biomedical Nanotechnology Vol. 2, 3645, 2006 ...
International Journal for Innovation Education and Research
Introductory courses such as General Chemistry I, General Physics General Biology and I need spec... more Introductory courses such as General Chemistry I, General Physics General Biology and I need special attention as students taking these courses are usually in their first year of the university. In addition to the language barrier for most of them, they also face other difficulties if these elementary courses are taught traditionally. Changing the routine method of teaching of these courses is therefore mandated. In this regard, podcasting of chemistry lectures was used as an add-on to the traditional and non-traditional methods of teaching chemistry to science and non-science students. Podcasts refer to video files that are distributed in a digital format through the Internet using personal computers or mobile devices. The pedagogical strategy is another way of identifying podcasts. Three distinct teaching approaches are evident in the current literature and include receptive viewing, problem-solving, and created video podcasts. Originally, podcasting was the name given to audio fi...
Advances in Polymer Technology
Polymers provide a wide range of properties, and these properties can be greatly enhanced and mod... more Polymers provide a wide range of properties, and these properties can be greatly enhanced and modified through polymer blending. Polymer blending combines the properties and advantages of their original polymers. This paper showcases hydrophobic polymers prepared through polymer blending; these blends are characterized and evaluated for their efficiency in the removal of crude oil spills from aqueous media. The application of these blends holds a great deal of importance in preserving the environment and the recovery of lost oil in spills. The blends are produced using polystyrene (PS) as the matrix polymer and individually blending poly(vinyl chloride) (PVC) and polyethylene (PE) with the PS consisting of proportions of 5–20 wt.% each. The blends are then electrospun into bead-free microfibers with interconnected porosities as shown by their respective scanned electron micrographs. All fibrous sorbents showed a high affinity towards the removal of crude oil, motor oil, and diesel s...
Journal of Bionic Engineering
Biomedicine & Pharmacotherapy
International Journal of Polymeric Materials and Polymeric Biomaterials
Scientific Reports
Poor prognoses remain the most challenging aspect of hepatocellular carcinoma (HCC) therapy. Cons... more Poor prognoses remain the most challenging aspect of hepatocellular carcinoma (HCC) therapy. Consequently, alternative therapeutics are essential to control HCC. This study investigated the anticancer effects of safranal against HCC using in vitro, in silico, and network analyses. Cell cycle and immunoblot analyses of key regulators of cell cycle, DNA damage repair and apoptosis demonstrated unique safranal-mediated cell cycle arrest at G2/M phase at 6 and 12 h, and at S-phase at 24 h, and a pronounced effect on DNA damage machinery. Safranal also showed pro-apoptotic effect through activation of both intrinsic and extrinsic initiator caspases; indicating ER stress-mediated apoptosis. Gene set enrichment analysis provided consistent findings where UPR is among the top terms of upregulated genes in response to safranal treatment. Thus, proteins involved in ER stress were regulated through safranal treatment to induce UPR in HepG2 cells.
Abu Dhabi International Petroleum Exhibition & Conference
Sensors and Actuators B: Chemical
Organic Electronics, 2017
International Journal of Oncology, 2016
Despite considerable advances in understanding hepatocellular carcinoma, it is one of the common ... more Despite considerable advances in understanding hepatocellular carcinoma, it is one of the common and deadliest cancers worldwide. Hence, increasing efforts are needed for early diagnosis and effective treatments. Saffron has been recently found to inhibit growth of liver cancer in rats. The aim of this study was to develop an effective method for treatment of liver cancer using magnetite nanoparticles (MNPs) coated with crocin, the main active component of saffron. MNPs were prepared and initially coated with dextran and a cross-linker to enhance conjugation of crocin using a modified coprecipitation method. Cultured HepG2 cells and diethylnitrosamine-injected mice were treated with corcincoated MNPs and analyzed using cell proliferation assay and immunohistochemical analysis, respectively. Treatment of HepG2 cells with crocin-coated MNPs led to a significant inhibition of their growth as compared to control or those treated with free crocin or uncoated MNPs. Histological examinations of the livers of diethylnitrosamine-injected mice revealed several precancerous changes: multiple proliferative hepatic foci, hyper-or dysplastic transformations of bile ducts/ductules, and nuclear atypia associated with polyploidy, karyomegaly, and vacuolation. Immunohistochemistry using antibodies specific for cell proliferation (Ki-67) and apoptosis (M30-CytoDEATH and Bcl-2) revealed their upregulation during development of precancerous lesions. Using antibodies specific for inflammation (cyclooxygenase-2), oxidative stress (glutathione) and angiogenesis (vascular endothelial growth factor) indicated the involvement of multiple signaling pathways in the development of precancerous lesions. Treatment with crocin-coated MNPs was associated with regression of precancerous lesions, significant upregulation of apoptotic cells and downregulation of Bcl-2 labeling and markers of cell proliferation, inflammation, oxidative stress and angiogenesis. In conclusion, crocin-coated MNPs are more effective than free corcin for treatment of liver precancerous lesions in mice. These findings will help to develop new modalities for early detection and treatment of liver precancerous lesions.
ASTRACT:Hydroxyapatite formed from low temperature setting calcium phosphate cements (CPC) are cu... more ASTRACT:Hydroxyapatite formed from low temperature setting calcium phosphate cements (CPC) are currently been used for various orthopaedic applications. CPCs are attractive candidates for the development of scaffolds for bone tissue engineering, since they are moldable, resorbable, set at physiological temperature without the use of toxic chemicals, and can be processed in an operating room setting. However they may have mechanical disadvantages which seriously limit them to non-load bearing orthopaedic applications. The aim of the present study was to develop composites from polyphosphazenes and calcium deficient hydroxyapatite precursors to form poorly crystalline hydroxyapatite-polymer composites. Composites were formed from calcium deficient hydroxyapatite precursors (Ca/P – 1.5, 1.6) and biodegradable polyphosphazenes, poly[bis(ethyl alanato)phosphazene] (PNEA) and poly[(50%ethyl alanato) (50%methyl phenoxy)phosphazene] (PNEA50mPh50) at physiological temperature. The results demonstrated that poorly crystalline hydroxyapatite that resembled the mineral component of bone was formed in the presence of biodegradable polyphosphazenes. The surface morphology of all the four composites was identical with a porous microstructure. The composites supported the adhesion and proliferation of osteoblast like MC3T3-E1 cells making them potential candidates for bone tissue engineering.
Nanoscale Advances, 2022
An overview of the MOF-based gas sensing materials with different electrical transduction princip... more An overview of the MOF-based gas sensing materials with different electrical transduction principles.
Advances in Experimental Medicine and Biology
Biodegradable scaffolds are useful tools in the field of tissue engineering and regenerative medi... more Biodegradable scaffolds are useful tools in the field of tissue engineering and regenerative medicine. The aim of this study was to test the potential of the human stem cells of apical papilla (SCAP) to attach, proliferate and differentiate on a polycaprolactone (PCL)-based scaffolds. SCAP were extracted from the root apical papillae of freshly extracted immature premolar teeth by using enzymatic digestion. Porous PCL scaffolds were fabricated using particle leaching method and NaCl or mannitol as porogens. SCAP of passage 3 were seeded on non-porous and porous PCL scaffolds for up to 14 days. For control, cells were cultured on glass coverslips. Picogreen DNA quantification was used to assay for cell proliferation. Cell differentiation and development of calcification nodules were examined using scanning electron microscopy and alizarin red staining. SCAP showed a comparable attachment, growth and proliferation patterns on PCL scaffolds and coverslips. Cell proliferation was enhanced on mannitol scaffolds at all time points. Calcification nodules were detected in all PCL scaffolds while it was not present on glass coverslips. These nodules were detected on NaCl-scaffolds by day 7 and on mannitol and non-porous scaffolds by day 14. In conclusion, SCAP were able to attach, proliferate and differentiate on PCL scaffolds without using any inductive media, indicating their potential application for dental tissue regeneration.
Scaffolds in Tissue Engineering - Materials, Technologies and Clinical Applications, Dec 13, 2017
Tissue engineering has been viewed as a valid approach toward the partial or total replacement of... more Tissue engineering has been viewed as a valid approach toward the partial or total replacement of defective tissues and organs. Recent advances in nanotechnology have made it possible to develop biocompatible materials at the micro-and nano-scales to be used as scaffolds for cellular growth and regeneration of defective tissues. Gastric mucosal lining is an example of soft tissues that are highly susceptible to damage due to various reasons including cancer or ulcer development. Current therapeutic approaches to these diseases have some limitations. This chapter describes the basis for development of a novel modality combining nanotechnology, stem cells, and tissue engineering for the replacement of defective gastric tissues using synthetic biocompatible scaffolds. These microfibrous scaffolds are seeded with gastric stem cells, which are studied for their proliferation and differentiation into functional gastric mucous cells.
Journal of Biomaterials Science, Polymer Edition, 2011
Microporous and Mesoporous Materials, 2013
ABSTRACT Transition-metal-doped γ-alumina with various dopant concentrations was prepared by stra... more ABSTRACT Transition-metal-doped γ-alumina with various dopant concentrations was prepared by straightforward template-free sol–gel method. The presence of dopant metal ions, generally, enhanced the gel formation and their behavior was dependent on the nature of the metal ion and its concentration. Certain ions, especially Fe3+, resulted in rapid formation of a transparent gel upon hydrolysis. The prepared doped γ-alumina powders weakly crystalline at low dopant ion concentrations, 2%, and became completely amorphous at a concentration of 10%. The morphology of the particles was also dependent on the dopant concentration. While dopant concentration of 2% resulted in nano-particles with significant amount of inter-particle mesopores, 10% concentration led to significant aggregation into larger particles. The prepared doped γ-Al2O3 as well as the undoped γ-Al2O3 showed high surface areas and pore volumes which were largely dependent on the nature of the dopant metal ions and on their concentrations. While composites with low dopant concentration, 2%, exhibited surface areas and pore volumes comparable to those of undoped γ-alumina, a considerable decrease was associated with higher concentrations. The changes in textural properties were referred to the evident enhanced sintering associated with high dopant concentrations.
Journal of …, 2006
Page 1. Delivered by Ingenta to: ? IP : 93.91.26.12 Fri, 10 Dec 2010 14:04:20 RESEARCH AR TICLE C... more Page 1. Delivered by Ingenta to: ? IP : 93.91.26.12 Fri, 10 Dec 2010 14:04:20 RESEARCH AR TICLE Copyright © 2006 American Scientific Publishers All rights reserved Printed in the United States of America Journal of Biomedical Nanotechnology Vol. 2, 3645, 2006 ...
International Journal for Innovation Education and Research
Introductory courses such as General Chemistry I, General Physics General Biology and I need spec... more Introductory courses such as General Chemistry I, General Physics General Biology and I need special attention as students taking these courses are usually in their first year of the university. In addition to the language barrier for most of them, they also face other difficulties if these elementary courses are taught traditionally. Changing the routine method of teaching of these courses is therefore mandated. In this regard, podcasting of chemistry lectures was used as an add-on to the traditional and non-traditional methods of teaching chemistry to science and non-science students. Podcasts refer to video files that are distributed in a digital format through the Internet using personal computers or mobile devices. The pedagogical strategy is another way of identifying podcasts. Three distinct teaching approaches are evident in the current literature and include receptive viewing, problem-solving, and created video podcasts. Originally, podcasting was the name given to audio fi...
Advances in Polymer Technology
Polymers provide a wide range of properties, and these properties can be greatly enhanced and mod... more Polymers provide a wide range of properties, and these properties can be greatly enhanced and modified through polymer blending. Polymer blending combines the properties and advantages of their original polymers. This paper showcases hydrophobic polymers prepared through polymer blending; these blends are characterized and evaluated for their efficiency in the removal of crude oil spills from aqueous media. The application of these blends holds a great deal of importance in preserving the environment and the recovery of lost oil in spills. The blends are produced using polystyrene (PS) as the matrix polymer and individually blending poly(vinyl chloride) (PVC) and polyethylene (PE) with the PS consisting of proportions of 5–20 wt.% each. The blends are then electrospun into bead-free microfibers with interconnected porosities as shown by their respective scanned electron micrographs. All fibrous sorbents showed a high affinity towards the removal of crude oil, motor oil, and diesel s...
Journal of Bionic Engineering
Biomedicine & Pharmacotherapy
International Journal of Polymeric Materials and Polymeric Biomaterials
Scientific Reports
Poor prognoses remain the most challenging aspect of hepatocellular carcinoma (HCC) therapy. Cons... more Poor prognoses remain the most challenging aspect of hepatocellular carcinoma (HCC) therapy. Consequently, alternative therapeutics are essential to control HCC. This study investigated the anticancer effects of safranal against HCC using in vitro, in silico, and network analyses. Cell cycle and immunoblot analyses of key regulators of cell cycle, DNA damage repair and apoptosis demonstrated unique safranal-mediated cell cycle arrest at G2/M phase at 6 and 12 h, and at S-phase at 24 h, and a pronounced effect on DNA damage machinery. Safranal also showed pro-apoptotic effect through activation of both intrinsic and extrinsic initiator caspases; indicating ER stress-mediated apoptosis. Gene set enrichment analysis provided consistent findings where UPR is among the top terms of upregulated genes in response to safranal treatment. Thus, proteins involved in ER stress were regulated through safranal treatment to induce UPR in HepG2 cells.
Abu Dhabi International Petroleum Exhibition & Conference
Sensors and Actuators B: Chemical
Organic Electronics, 2017
International Journal of Oncology, 2016
Despite considerable advances in understanding hepatocellular carcinoma, it is one of the common ... more Despite considerable advances in understanding hepatocellular carcinoma, it is one of the common and deadliest cancers worldwide. Hence, increasing efforts are needed for early diagnosis and effective treatments. Saffron has been recently found to inhibit growth of liver cancer in rats. The aim of this study was to develop an effective method for treatment of liver cancer using magnetite nanoparticles (MNPs) coated with crocin, the main active component of saffron. MNPs were prepared and initially coated with dextran and a cross-linker to enhance conjugation of crocin using a modified coprecipitation method. Cultured HepG2 cells and diethylnitrosamine-injected mice were treated with corcincoated MNPs and analyzed using cell proliferation assay and immunohistochemical analysis, respectively. Treatment of HepG2 cells with crocin-coated MNPs led to a significant inhibition of their growth as compared to control or those treated with free crocin or uncoated MNPs. Histological examinations of the livers of diethylnitrosamine-injected mice revealed several precancerous changes: multiple proliferative hepatic foci, hyper-or dysplastic transformations of bile ducts/ductules, and nuclear atypia associated with polyploidy, karyomegaly, and vacuolation. Immunohistochemistry using antibodies specific for cell proliferation (Ki-67) and apoptosis (M30-CytoDEATH and Bcl-2) revealed their upregulation during development of precancerous lesions. Using antibodies specific for inflammation (cyclooxygenase-2), oxidative stress (glutathione) and angiogenesis (vascular endothelial growth factor) indicated the involvement of multiple signaling pathways in the development of precancerous lesions. Treatment with crocin-coated MNPs was associated with regression of precancerous lesions, significant upregulation of apoptotic cells and downregulation of Bcl-2 labeling and markers of cell proliferation, inflammation, oxidative stress and angiogenesis. In conclusion, crocin-coated MNPs are more effective than free corcin for treatment of liver precancerous lesions in mice. These findings will help to develop new modalities for early detection and treatment of liver precancerous lesions.
ASTRACT:Hydroxyapatite formed from low temperature setting calcium phosphate cements (CPC) are cu... more ASTRACT:Hydroxyapatite formed from low temperature setting calcium phosphate cements (CPC) are currently been used for various orthopaedic applications. CPCs are attractive candidates for the development of scaffolds for bone tissue engineering, since they are moldable, resorbable, set at physiological temperature without the use of toxic chemicals, and can be processed in an operating room setting. However they may have mechanical disadvantages which seriously limit them to non-load bearing orthopaedic applications. The aim of the present study was to develop composites from polyphosphazenes and calcium deficient hydroxyapatite precursors to form poorly crystalline hydroxyapatite-polymer composites. Composites were formed from calcium deficient hydroxyapatite precursors (Ca/P – 1.5, 1.6) and biodegradable polyphosphazenes, poly[bis(ethyl alanato)phosphazene] (PNEA) and poly[(50%ethyl alanato) (50%methyl phenoxy)phosphazene] (PNEA50mPh50) at physiological temperature. The results demonstrated that poorly crystalline hydroxyapatite that resembled the mineral component of bone was formed in the presence of biodegradable polyphosphazenes. The surface morphology of all the four composites was identical with a porous microstructure. The composites supported the adhesion and proliferation of osteoblast like MC3T3-E1 cells making them potential candidates for bone tissue engineering.