The crystal structure and morphology of a family of aromatic-aliphatic azomethine polyethers (whe... more The crystal structure and morphology of a family of aromatic-aliphatic azomethine polyethers (where the aliphatic unit was composed of CH$\sb2$ units ranging in length from n = 1, 4, 7, 8, 9 and 10) has been examined primarily by Electron microscopy(EM) and Electron diffraction(ED).Chain folded single crystals with lamellar thicknesses of 35-100A, in which the molecular axis is perpendicular to the substrate, have been grown by slow cooling thin films from the nematic state on a glycerin surface for n = 4, 8 and 10 with AZMEP-7 yielding disclination domains with isolated regions of chain folded lamellae. For as-polymerized AZMEP-10, the lamellae were found to be 35A thick The thinness of the lamellae and their tilt relative to the substrate and molecular axis suggests a regular, adjacent re-entry type folding every three repeat distances. AZMEP-1 was found to crystallize as striated films of near uniform thickness; in these samples, the molecular axes are parallel to the substrate, yielding fiber-type ED patterns. AZMEP-9 samples yielded a similar morphology, but no ED patterns were obtained.Our findings on samples crystallized as thin films has added to earlier findings by S. Kent and P. H. Geil, which gave the first conclusive evidence of chain folding in lcps. Claims were also made by them, and is supported by our findings, of the presence of chain folding in the nematic state.Sheared samples with lamellae ca. 250A and more or less perpendicular to the shear direction have been obtained for n = 1, 4, 7, 8, 9 and 10. Annealing below T$\rm\sb{k-m}$ has been shown to increase the lamellar thickness and overall order. ED from sheared, annealed samples surprisingly yield h01 single crystal patterns rather than the expected fiber patterns, which have rotational symmetry. This finding is unique, as far as we know, for sheared polymer samples. The h01 single crystal nature of these samples was verified by dark field EM.Lamellar single crystals (ca. 100A thick) have been grown by the constrained film melt polymerization technique for n = 4, 8 and 9, yielding single crystals suitable for ED. The ED data from these samples, in conjunction with data obtained from the sheared samples, has permitted characterization of the unit cells.We have examined creep above and below the nominal Tg in both the viscoelastic and viscoplastic load ranges for AS4/J1 uniaxial composites. Surprisingly, long term creep in tension does not appear to be a problem; it was found to be compensated by shrinkage due to physical aging, resulting in negative creep in the viscoelastic load range, and near zero creep in the viscoplastic load range. This fact makes the time-temperature superposition principle invalid for long term predictions; it actually overpredicts it in tension. The fact that physical aging occurs above Tg in subcrystalline polymers is attributed to the presence of a distributed Tg.U of I OnlyETDs are only available to UIUC Users without author permissio
The ever-broadening scope of phage research has left behind the simplistic view of studying phage... more The ever-broadening scope of phage research has left behind the simplistic view of studying phages as just model systems in phage biology to a much broader application ranging from ecological management to immunity. Improved throughput technology in crystallography and structural studies has helped our understanding of these systems as supramolecular machines that possess the capacity of self-assembly. The idea of phages as self-assembling supramolecular nano-machines that are bioactive biomaterials in characteristics, tunable and easily producible have lent its utility to recent fields such as regenerative medicine and tissue engineering. Due to low metabolic activity and slow nutrient diffusion within cartilage, damage to this tissue often inevitably consist of slow and delayed regeneration and healing, the restriction of blood from reaching most part of this tissue and the resultant limitations in the availability of oxygen and other essential amino acids dictates a very slow sys...
Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois,... more Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2005
This paper is primarily focused in studying the effects of nanoclay particles such as montmorillo... more This paper is primarily focused in studying the effects of nanoclay particles such as montmorillonite on improving mechanical and thermal properties of fiber reinforced polymer matrix composite materials. Basic correlations between polymer morphology, strength, modulus, toughness, and thermal stability of thermoset nanocomposites were investigated as a function of layered silicate content. S2-glass/epoxy-clay nanocomposites were manufactured through an affordable vacuum assisted resin infusion method (VARIM). The nanocomposites are formed during polymerization when the adsorbing monomer separates the clay particles into nanometer scales. Transmission electron microscopy (TEM) and wide angle X-ray diffraction(WAXD) were used to characterize the morphology of the dispersed clay particles. The thermal properties such as onset of decomposition and glass transition temperatures were determined by Thermo Gravimetric Analysis (TGA) and Dynamic Modulus Analyzer (DMA). Mechanical properties ...
Articular cartilage defects, and subsequent degeneration, are prevalent and account for the poor ... more Articular cartilage defects, and subsequent degeneration, are prevalent and account for the poor quality of life of most elderly persons; they are also one of the main predisposing factors to osteoarthritis. Articular cartilage is an avascular tissue and, thus, has limited capacity for healing and self-repair. Damage to the articular cartilage by trauma or pathological causes is irreversible. Many approaches to repair cartilage have been attempted with some potential; however, there is no consensus on any ideal therapy. Tissue engineering holds promise as an approach to regenerate damaged cartilage. Since cell adhesion is a critical step in tissue engineering, providing a 3D microenvironment that recapitulates the cartilage tissue is vital to inducing cartilage regeneration. Decellularized materials have emerged as promising scaffolds for tissue engineering, since this procedure produces scaffolds from native tissues that possess structural and chemical natures that are mimetic of t...
This study investigated the efficacy of combined 3D printing and electrospinning to form hybrid 3... more This study investigated the efficacy of combined 3D printing and electrospinning to form hybrid 3D scaffolds to provide inductive cues for stems cells to differentiate into an osteogenic lineage. Hybrid scaffolds mimicking the three-dimensional architecture and bioactivity of the extracellular matrix were fabricated by co-electrospinning poly(lactic acid) (PLA) and hydroxyapatite (HA) in varying percentages onto 3D-printed PLA. The 3D-printed scaffold provided a porous structure with the requisite mechanical properties for a bone tissue scaffold. Coating the PLA scaffold with electrospun nanofibers provided bioactivity. The nano-topology of the scaffold surface promoted cell attachment, and that affinity was increased by incorporating HA. It was also found that the HA provided inductive cues to stem cells to differentiate into an osteogenic lineage. The scaffolds promoted the bone mesenchymal stem cell (BMSC) proliferation, induced cellular synthesis of extracellular matrix molecules as well as controlled the expression of osteogenic cell markers in BMSC.
Monocyte chemo-attractant protein (MCP-1) is a chemokine, which recruits monocytes, neutrophils, ... more Monocyte chemo-attractant protein (MCP-1) is a chemokine, which recruits monocytes, neutrophils, and lymphocytes in response to trauma and proinflammatory cytokines such as TNF-α. MCP-1 generally is not expressed in healthy individuals, but in response to various stressful stimuli it gets up-regulated, which in turn contributes to increased inflammation. MCP-1 has been implicated in mediating apoptosis by producing a proapoptotic protein designated MCP-induced protein (MCPIP). Resveratrol (RES), a polyphenolic compound found in the skin of red fruits, exhibits anti-inflammatory, anti-oxidative, anti-cancer, and anti-proliferative characteristics. In this study, we hypothesized that the functionalization of RES with detonated nano-diamond (DND, hereafter called fDND) will enhance the effective delivery of RES to tumor cell and impact the modulation of molecular mechanisms in murine prostate cancer (PCa) cells. This hypothesis was tested on mouse PCa cell lines, derived from transgeni...
In this study, we report a biohybrid oriented fibrous scaffold based on nanofibers of poly(l-lact... more In this study, we report a biohybrid oriented fibrous scaffold based on nanofibers of poly(l-lactic acid) (PLLA)/fibrin produced by electrospinning and subsequent post-treatment. Induced hydrolytic degradation of the fibers in 0.25 M NaOH solution for various time periods followed by the immobilization of fibrin on the hydrolyzed fiber surfaces was shown to significantly affect the mechanical properties, with the tensile strength (40.6 MPa ± 1.3) and strain at failure (38% ± 4.5) attaining a value within the range of human ligaments and ligament-replacement grafts. Unidirectional electrospinning with a mandrel rotational velocity of 26.4 m/s produced highly aligned fibers with an average diameter of 760 ± 96 nm. After a 20-min hydrolysis treatment in NaOH solution, this was further reduced to an average of 457 ± 89 nm, which is within the range of collagen bundles found in ligament tissue. Based on the results presented herein, the authors hypothesize that a combination of fiber ori...
We have recently developed nanostructured coupling agents designed to couple micron scale reinfor... more We have recently developed nanostructured coupling agents designed to couple micron scale reinforcements to the composite matrix. Scanning electron microscopy and Raman spectroscopy show evidence of carbon nanotubes deposited onto the carbon fibers. X-ray photoelectron spectroscopy provides evidence of a covalent link formed between the carbon nanotubes and the sizing on the carbon fibers. Laser flash analysis shows significant enhancement in thermal conductivity of composites fabricated with these modified fibers. Keywords: Carbon nanotubes, thermal conductivity, composites Cite this Article Theodore M, Fielding J, Green K et al. Thermal Conductivity of CNT-Deposited Carbon Fiber Epoxy Matrix Composites. Journal of Polymer & Composites. 2015; 3(2): 22–34p
Nanotechnology has a potential impact in the detection, treatment, and monitoring of cancer signi... more Nanotechnology has a potential impact in the detection, treatment, and monitoring of cancer significantly, and to revolutionize cancer nanomedicine. Nanoparticles are particles with dimensions in the 1–100 nm range, the scale at which scale materials have unique physicochemical properties including ultrasmall size, large surface-to-mass ratio, high reactivity, and unique interactions with biological systems. Advanced nanoparticulate designs as “magic bullets” postulated by Paul Ehrlich, the Founder of chemotherapy, are now under in-lab development, including with combined capabilities for targeting, imaging, and delivering multiple drugs with enhanced therapeutic index and treatment efficacy to revolutionize the current cancer therapies in the coming years. Specifically, prostate cancer develops in the prostate, a gland in the male reproductive system. As the disease progresses and becomes more aggressive, the cancerous lesions spread beyond the prostate locally to the rectum or bla...
The crystal structure and morphology of a family of aromatic-aliphatic azomethine polyethers (whe... more The crystal structure and morphology of a family of aromatic-aliphatic azomethine polyethers (where the aliphatic unit was composed of CH$\sb2$ units ranging in length from n = 1, 4, 7, 8, 9 and 10) has been examined primarily by Electron microscopy(EM) and Electron diffraction(ED).Chain folded single crystals with lamellar thicknesses of 35-100A, in which the molecular axis is perpendicular to the substrate, have been grown by slow cooling thin films from the nematic state on a glycerin surface for n = 4, 8 and 10 with AZMEP-7 yielding disclination domains with isolated regions of chain folded lamellae. For as-polymerized AZMEP-10, the lamellae were found to be 35A thick The thinness of the lamellae and their tilt relative to the substrate and molecular axis suggests a regular, adjacent re-entry type folding every three repeat distances. AZMEP-1 was found to crystallize as striated films of near uniform thickness; in these samples, the molecular axes are parallel to the substrate, yielding fiber-type ED patterns. AZMEP-9 samples yielded a similar morphology, but no ED patterns were obtained.Our findings on samples crystallized as thin films has added to earlier findings by S. Kent and P. H. Geil, which gave the first conclusive evidence of chain folding in lcps. Claims were also made by them, and is supported by our findings, of the presence of chain folding in the nematic state.Sheared samples with lamellae ca. 250A and more or less perpendicular to the shear direction have been obtained for n = 1, 4, 7, 8, 9 and 10. Annealing below T$\rm\sb{k-m}$ has been shown to increase the lamellar thickness and overall order. ED from sheared, annealed samples surprisingly yield h01 single crystal patterns rather than the expected fiber patterns, which have rotational symmetry. This finding is unique, as far as we know, for sheared polymer samples. The h01 single crystal nature of these samples was verified by dark field EM.Lamellar single crystals (ca. 100A thick) have been grown by the constrained film melt polymerization technique for n = 4, 8 and 9, yielding single crystals suitable for ED. The ED data from these samples, in conjunction with data obtained from the sheared samples, has permitted characterization of the unit cells.We have examined creep above and below the nominal Tg in both the viscoelastic and viscoplastic load ranges for AS4/J1 uniaxial composites. Surprisingly, long term creep in tension does not appear to be a problem; it was found to be compensated by shrinkage due to physical aging, resulting in negative creep in the viscoelastic load range, and near zero creep in the viscoplastic load range. This fact makes the time-temperature superposition principle invalid for long term predictions; it actually overpredicts it in tension. The fact that physical aging occurs above Tg in subcrystalline polymers is attributed to the presence of a distributed Tg.U of I OnlyETDs are only available to UIUC Users without author permissio
The ever-broadening scope of phage research has left behind the simplistic view of studying phage... more The ever-broadening scope of phage research has left behind the simplistic view of studying phages as just model systems in phage biology to a much broader application ranging from ecological management to immunity. Improved throughput technology in crystallography and structural studies has helped our understanding of these systems as supramolecular machines that possess the capacity of self-assembly. The idea of phages as self-assembling supramolecular nano-machines that are bioactive biomaterials in characteristics, tunable and easily producible have lent its utility to recent fields such as regenerative medicine and tissue engineering. Due to low metabolic activity and slow nutrient diffusion within cartilage, damage to this tissue often inevitably consist of slow and delayed regeneration and healing, the restriction of blood from reaching most part of this tissue and the resultant limitations in the availability of oxygen and other essential amino acids dictates a very slow sys...
Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois,... more Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2005
This paper is primarily focused in studying the effects of nanoclay particles such as montmorillo... more This paper is primarily focused in studying the effects of nanoclay particles such as montmorillonite on improving mechanical and thermal properties of fiber reinforced polymer matrix composite materials. Basic correlations between polymer morphology, strength, modulus, toughness, and thermal stability of thermoset nanocomposites were investigated as a function of layered silicate content. S2-glass/epoxy-clay nanocomposites were manufactured through an affordable vacuum assisted resin infusion method (VARIM). The nanocomposites are formed during polymerization when the adsorbing monomer separates the clay particles into nanometer scales. Transmission electron microscopy (TEM) and wide angle X-ray diffraction(WAXD) were used to characterize the morphology of the dispersed clay particles. The thermal properties such as onset of decomposition and glass transition temperatures were determined by Thermo Gravimetric Analysis (TGA) and Dynamic Modulus Analyzer (DMA). Mechanical properties ...
Articular cartilage defects, and subsequent degeneration, are prevalent and account for the poor ... more Articular cartilage defects, and subsequent degeneration, are prevalent and account for the poor quality of life of most elderly persons; they are also one of the main predisposing factors to osteoarthritis. Articular cartilage is an avascular tissue and, thus, has limited capacity for healing and self-repair. Damage to the articular cartilage by trauma or pathological causes is irreversible. Many approaches to repair cartilage have been attempted with some potential; however, there is no consensus on any ideal therapy. Tissue engineering holds promise as an approach to regenerate damaged cartilage. Since cell adhesion is a critical step in tissue engineering, providing a 3D microenvironment that recapitulates the cartilage tissue is vital to inducing cartilage regeneration. Decellularized materials have emerged as promising scaffolds for tissue engineering, since this procedure produces scaffolds from native tissues that possess structural and chemical natures that are mimetic of t...
This study investigated the efficacy of combined 3D printing and electrospinning to form hybrid 3... more This study investigated the efficacy of combined 3D printing and electrospinning to form hybrid 3D scaffolds to provide inductive cues for stems cells to differentiate into an osteogenic lineage. Hybrid scaffolds mimicking the three-dimensional architecture and bioactivity of the extracellular matrix were fabricated by co-electrospinning poly(lactic acid) (PLA) and hydroxyapatite (HA) in varying percentages onto 3D-printed PLA. The 3D-printed scaffold provided a porous structure with the requisite mechanical properties for a bone tissue scaffold. Coating the PLA scaffold with electrospun nanofibers provided bioactivity. The nano-topology of the scaffold surface promoted cell attachment, and that affinity was increased by incorporating HA. It was also found that the HA provided inductive cues to stem cells to differentiate into an osteogenic lineage. The scaffolds promoted the bone mesenchymal stem cell (BMSC) proliferation, induced cellular synthesis of extracellular matrix molecules as well as controlled the expression of osteogenic cell markers in BMSC.
Monocyte chemo-attractant protein (MCP-1) is a chemokine, which recruits monocytes, neutrophils, ... more Monocyte chemo-attractant protein (MCP-1) is a chemokine, which recruits monocytes, neutrophils, and lymphocytes in response to trauma and proinflammatory cytokines such as TNF-α. MCP-1 generally is not expressed in healthy individuals, but in response to various stressful stimuli it gets up-regulated, which in turn contributes to increased inflammation. MCP-1 has been implicated in mediating apoptosis by producing a proapoptotic protein designated MCP-induced protein (MCPIP). Resveratrol (RES), a polyphenolic compound found in the skin of red fruits, exhibits anti-inflammatory, anti-oxidative, anti-cancer, and anti-proliferative characteristics. In this study, we hypothesized that the functionalization of RES with detonated nano-diamond (DND, hereafter called fDND) will enhance the effective delivery of RES to tumor cell and impact the modulation of molecular mechanisms in murine prostate cancer (PCa) cells. This hypothesis was tested on mouse PCa cell lines, derived from transgeni...
In this study, we report a biohybrid oriented fibrous scaffold based on nanofibers of poly(l-lact... more In this study, we report a biohybrid oriented fibrous scaffold based on nanofibers of poly(l-lactic acid) (PLLA)/fibrin produced by electrospinning and subsequent post-treatment. Induced hydrolytic degradation of the fibers in 0.25 M NaOH solution for various time periods followed by the immobilization of fibrin on the hydrolyzed fiber surfaces was shown to significantly affect the mechanical properties, with the tensile strength (40.6 MPa ± 1.3) and strain at failure (38% ± 4.5) attaining a value within the range of human ligaments and ligament-replacement grafts. Unidirectional electrospinning with a mandrel rotational velocity of 26.4 m/s produced highly aligned fibers with an average diameter of 760 ± 96 nm. After a 20-min hydrolysis treatment in NaOH solution, this was further reduced to an average of 457 ± 89 nm, which is within the range of collagen bundles found in ligament tissue. Based on the results presented herein, the authors hypothesize that a combination of fiber ori...
We have recently developed nanostructured coupling agents designed to couple micron scale reinfor... more We have recently developed nanostructured coupling agents designed to couple micron scale reinforcements to the composite matrix. Scanning electron microscopy and Raman spectroscopy show evidence of carbon nanotubes deposited onto the carbon fibers. X-ray photoelectron spectroscopy provides evidence of a covalent link formed between the carbon nanotubes and the sizing on the carbon fibers. Laser flash analysis shows significant enhancement in thermal conductivity of composites fabricated with these modified fibers. Keywords: Carbon nanotubes, thermal conductivity, composites Cite this Article Theodore M, Fielding J, Green K et al. Thermal Conductivity of CNT-Deposited Carbon Fiber Epoxy Matrix Composites. Journal of Polymer & Composites. 2015; 3(2): 22–34p
Nanotechnology has a potential impact in the detection, treatment, and monitoring of cancer signi... more Nanotechnology has a potential impact in the detection, treatment, and monitoring of cancer significantly, and to revolutionize cancer nanomedicine. Nanoparticles are particles with dimensions in the 1–100 nm range, the scale at which scale materials have unique physicochemical properties including ultrasmall size, large surface-to-mass ratio, high reactivity, and unique interactions with biological systems. Advanced nanoparticulate designs as “magic bullets” postulated by Paul Ehrlich, the Founder of chemotherapy, are now under in-lab development, including with combined capabilities for targeting, imaging, and delivering multiple drugs with enhanced therapeutic index and treatment efficacy to revolutionize the current cancer therapies in the coming years. Specifically, prostate cancer develops in the prostate, a gland in the male reproductive system. As the disease progresses and becomes more aggressive, the cancerous lesions spread beyond the prostate locally to the rectum or bla...
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