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- Title
- ENHANCED DEGRADATION AND PEPTIDE SPECIFICITY OF MMP-SENSITIVE SCAFFOLDS FOR NEOVASCULARIZATION OF ENGINEERED TISSUES
- Creator
- Sokic, Sonja
- Date
- 2013, 2013-07
- Description
-
Biomaterial strategies for engineering tissues of clinically relevant size require the formation of rapid and stable neovascularization. The...
Show moreBiomaterial strategies for engineering tissues of clinically relevant size require the formation of rapid and stable neovascularization. The ability of an engineered scaffold to induce vascularization is highly dependent on its rate of degradation. During the process of material degradation, the scaffold should degrade in a manner allowing for cellular infiltration, lumen formation, and extracellular matrix (ECM) synthesis. Matrix metalloproteinases (MMPs) play a key role in mediating cell-induced proteolytic matrix degradation, remodeling, and controlled neovascularization. Poly (ethylene glycol) PEG hydrogels have been extensively investigated as scaffolds for tissue engineering applications due to their ease of chemical modification allowing for the recapitulation of key aspects of the neovascularization process. The goal of the work described in this thesis was to develop strategies to enhance and control the degradation of MMP-sensitive PEG diacrylate (PEGDA) hydrogels without inducing changes to the bulk physical and mechanical properties of the material and to further study the effect of the cleavage site concentration and MMP-sensitive peptide substrate specificity on the rate of neovascularization and tissue remodeling in vitro and in vivo. In the first part of this study, a detailed investigation was completed to investigate the effects of the mechanical and physical properties of the scaffolds as well as the role of proteolytically mediated hydrogel degradation on 3D fibroblast invasion within MMPsensitive PEGDA hydrogels. Initial studies focused on the use of a modified version of a previously published multistep conjugation method to generate degradable PEGDA macromer conjugates containing variations in the number of MMP-sensitive domains. Theoretical and experimental characterization of this multistep conjugation demonstrated xi that this method leads to the formation of multiple species that directly affect the compressive modulus and degradation rate of the scaffold making it difficult to control degradation independent of alterations in the bulk physical and mechanical hydrogel properties. After manipulation of multiple polymerization conditions, hydrogels with similar compressive moduli but different hydrogel degradation rates were synthesized. These initial studies showed that an increase in the incorporation of proteolytically sensitive domains in PEGDA hydrogels of similar modulus lead to enhanced degradation and 3D fibroblast invasion. In this study, the role of soluble FGF-1 on fibroblast invasion within these scaffolds was investigated and it was demonstrated that the inclusion of FGF-1 in the scaffolds results in further enhancement of fibroblast invasion in a dosedependent fashion. Further studies were necessary to develop a more controllable and robust approach in tuning scaffold degradation independent of alterations in the bulk physical and mechanical properties. In order to address this, a novel approach was developed to engineer protease-sensitive peptides with multiple proteolytic cleavage sites that could be covalently crosslinked into hydrogels without compromising the physical and mechanical biomaterial properties. This approach avoided the need for utilizing a multistep conjugation process as peptides could be incorporated into the backbone of PEG using a single step conjugation. Using this approach, hydrogels formed with the engineered peptides led to significantly enhanced degradation and neovascularization in vitro as compared to scaffolds with a single protease sensitive peptide between crosslinks. In addition, hydrogels with enhanced susceptibility to degradation promoted vascularization over a wider range of matrix properties. This approach allowed for controlled xii concentration of the proteolytic cleavage sites within the matrix and thus tuning of hydrogel degradation for tissue engineering applications. In the final study, MMP-sensitive peptide substrates specific to degradation by MMPs known to be expressed during neovascularization were screened for degradation and their role in neovascularization. MMP-sensitive PEGDA hydrogels (SSite and TriSite) were synthesized with peptide substrates sensitive to cleavage by MMP-2, MMP- 9, MMP-14, a mixed sequence of MMP-2, 9 and 14, and compared to the peptide substrate used in the previous studies, which is degraded by collagenase enzymes. The hydrogels were evaluated for their sensitivity and specificity to degradation by MMPs, in terms of cleavage site concentration, and for their role in neovascularization and tissue remodeling in vitro and in vivo. The presented approach allows for the incorporation of varying cleavage site concentration and MMP-sensitive peptide substrates into PEG hydrogels without alterations in the mechanical and physical properties of the hydrogels. Results showed that without the incorporation of growth factors in this scaffold, vascularization and tissue invasion was supported in all MMP-sensitive hydrogel groups regardless of the MMP-sensitive peptide substrate embedded in the matrix. In addition, the cleavage site concentration had a profound impact in enhancing vascularization in vitro and tissue invasion in vivo. These techniques can be used to tune the properties of polymer scaffolds for neovascularization and tissue remodeling. In addition, these studies provide insight into the effect of the physical, mechanical, and degradative properties of these systems and on the role of cleavage site concentration, and MMP substrate specificity on xiii neovascularization and tissue invasion within proteolytically degradable PEG hydrogel constructs.
PH.D in Biomedical Engineering, July 2013
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- Title
- AN ENERGY EFFICIENT ROUTING PROTOCOL FOR WIRELESS SENSOR NETWORKS
- Creator
- Lara, Aurobinda
- Date
- 2012-04-27, 2012-05
- Description
-
Wireless distributed microsensor systems will enable the reliable monitoring of a variety of environments for both civil and military...
Show moreWireless distributed microsensor systems will enable the reliable monitoring of a variety of environments for both civil and military applications. A wireless sensor network consists of nodes that can communicate with each other via wireless links. One way to support efficient communication between sensors is to organize the network into several groups, called clusters, with each cluster electing one node as the head of cluster. Energy efficiency is of great importance for the wireless sensor network (WSN). A popular way to save energy is to construct clusters for data aggregation and forwarding. In this thesis a distributed cluster algorithm is studied to improve the energy consumption efficiency. It was observed that the cluster head has to lie within the transmission range of the base station (sink node) and the distance between cluster head and base station is critical for the energy consumption performance, we proposed a pseudo-cluster and virtual hierarchical clustering scheme (PC-LEACH), which considers the power level of the non-cluster head nodes and the residual energy level during the cluster head selection stage. Consequently we could better balance the chance of being cluster head for all nodes. Simulation results show that the scheme is able to result in longer network lifetime than the well-known protocol LEACH.
M.S. in Electrical Engineering, May 2012
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- Title
- Signal Compression or Expansion System Using Variable Azimuth Magnetic Recording
- Creator
- Camras, Marvin
- Date
- 4/24/2009, 1970-09-08
- Description
-
Sponsorship: IIT Research Institute
United States Patent
- Title
- Hierarchical Structured Abstract Data Organization System
- Creator
- Frieder, Ophir, Kapoor, Sanjiv
- Date
- 2012-06-27, 2012-06-26
- Description
-
A method in a data processing system and apparatus for organizing files, web pages, or web site members organized in a traditional first...
Show moreA method in a data processing system and apparatus for organizing files, web pages, or web site members organized in a traditional first hierarchical file structure that is on a recordable medium of a data processing system. A user-defined metalabel is assigned to each of the electronic files, web pages, or web site members. The electronic files, web pages, or web site members are organized as a function of the metalabels into a second hierarchical file structure existing simultaneously with the first hierarchical file structure on the recordable medium of the data processing system. The files, web pages, or web site members can be organized or grouped by the metalabels for efficient searching or following conversations of group members on social networking sites.
Sponsorship: Illinois Institute of Technology
United States Patent
Primary US Patent Classification 707/802
US Patent Classification 707/805
US Patent Classification 707/822
US Patent Classification 707/828
US Patent Classification 707/829
US Patent Classification 715/733
US Patent Classification 715/736
US Patent Classification 715/845
US Patent Classification 715/853
International Patent Classification G06F7/00
International Patent Classification G06F17/30
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- Title
- Alleviating Homelessness in Chicago
- Creator
- Degroff, Justin
- Date
- 2011, 2011-05
- Description
-
Alleviating homelessness in Chicago through the creation of a network of self-sufficient, revenue generating support nodes.
- Title
- Magnetic Duplicating Method and Means
- Creator
- Camras, Marvin
- Date
- 1954-01-19
- Description
-
Sponsorship: Armour Research Foundation of Illinois Institute of Technology
United States Patent
- Title
- Test of a 40 hp Halladay chasis
- Creator
- Fors, A. F., Kuehn, H. R., Semerak, A. W.
- Date
- 2009, 1913
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/testof40hphallad00fors
Thesis (B.S.)--Armour Institute of Technology
- Title
- JET MIXING CONTROL USING EXCITATION FROM MINIATURE OSCILLATING JETS
- Creator
- Raman, G, Cornelius, D
- Date
- 1995-02
- Publisher
- AMER INST AERONAUT ASTRONAUT
- Title
- ENHANCEMENT OF BIODESULFURIZATION IN RHODOCOCCUS SPECIES (IGTS8) BY THE EXPRESSION OF VITREOSCILLA HEMOGLOBIN
- Creator
- Shivdas, Vrushali D.
- Date
- 2013, 2013-07
- Description
-
The bacterium Rhodococcus sp. IGTS8 contains the dsz operon, which encodes a three enzyme pathway (the “4S pathway”) that is able to...
Show moreThe bacterium Rhodococcus sp. IGTS8 contains the dsz operon, which encodes a three enzyme pathway (the “4S pathway”) that is able to mineralize the sulfur contained in dibenzothiophene (DBT), an organic sulfur containing molecule found in petroleum. The gene vgb, which encodes Vitreoscilla hemoglobin (VHb), has shown wide usefulness in enhancing productivity and other useful properties when expressed in heterologous hosts. We engineered strain IGTS8 to express VHb and measured the effects on growth and desulfurization of DBT, using minimal medium containing DBT as the sole source of sulfur. VHb was clearly detected in the engineered strain using the standard COdifference spectral analysis, but its level (0.38-0.63 nmoles/gm wet weight of cells) was about 10-fold lower than commonly seen for expression of VHb in other heterologous bacterial hosts. The VHb-expressing strain was tested for growth at both low and high aeration in minimal medium containing DBT as sole sulfur source; growth was about 50% lower at low aeration compared with high aeration. Despite this, metabolism of DBT (as detected by accumulation of the end product of the 4S pathway, 2-Hydroxy biphenyl (2-HBP), in the growth medium) was about 30 % higher in the low aeration compared to the high aeration culture. A possible explanation for these results is direct enhancement of the first two (monooxygenase) steps in conversion of DBT to 2-HBP. It was thus concluded from the studies that the expression of vgb in Rhodococcus sp. IGTS8 enhances the process of biodesulfurization under conditions of low aeration
M.S. in Biology, July 2013
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- Title
- PSECMAC Intelligent Insulin Schedule for Diabetic Blood Glucose Management Under Nonmeal Announcement
- Creator
- Teddy, S. D., Quek, C., Lai, E. M.-k., Cinar, A.
- Date
- 2010-03
- Publisher
- IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
- Description
-
Therapeutically, the closed-loop blood glucose-insulin regulation paradigm via a controllable insulin pump offers a potential solution to the...
Show moreTherapeutically, the closed-loop blood glucose-insulin regulation paradigm via a controllable insulin pump offers a potential solution to the management of diabetes. However, the development of such a closed-loop regulatory system to date has been hampered by two main issues: 1) the limited knowledge on the complex human physiological process of glucose-insulin metabolism that prevents a precise modeling of the biological blood glucose control loop; and 2) the vast metabolic biodiversity of the diabetic population due to varying exogneous and endogenous disturbances such as food intake, exercise, stress, and hormonal factors, etc. In addition, current attempts of closed-loop glucose regulatory techniques generally require some form of prior meal announcement and this constitutes a severe limitation to the applicability of such systems. In this paper, we present a novel intelligent insulin schedule based on the pseudo self-evolving cerebellar model articulation controller (PSECMAC) associative learning memory model that emulates the healthy human insulin response to food ingestion. The proposed PSECMAC intelligent insulin schedule requires no prior meal announcement and delivers the necessary insulin dosage based only on the observed blood glucose fluctuations. Using a simulated healthy subject, the proposed PSECMAC insulin schedule is demonstrated to be able to accurately capture the complex human glucose-insulin dynamics and robustly addresses the intraperson metabolic variability. Subsequently, the PSECMAC intelligent insulin schedule is employed on a group of type-1 diabetic patients to regulate their impaired blood glucose levels. Preliminary simulation results are highly encouraging. The work reported in this paper represents a major paradigm shift in the management of diabetes where patient compliance is poor and the need for prior meal announcement under current treatment regimes poses a significant challenge to an active lifestyle.
Endnote format citation for DOI:10.1109/TNN.2009.2036726
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- Title
- Digital Urban Park
- Creator
- Thornton, Alastair
- Date
- 5/4/2011, 2011-05
- Description
-
This project is a park that utilizes social networks and interactivity to convey and make physical the internet. This is explored through...
Show moreThis project is a park that utilizes social networks and interactivity to convey and make physical the internet. This is explored through three parts and varying levels of group interaction between both the users of the space and by the spaces direct influence from the internet.
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- Title
- HIGH PERFORMANCE, HIGH STABILITY AND LOW POWER SRAM DESIGN BY USING CARBON NANOTUBE FIELD EFFECT TRANSISTORS
- Creator
- Wang, Wei
- Date
- 2012-07-07, 2012-07
- Description
-
As the feature size of silicon semiconductor devices scales down to nanometer range, planar bulk CMOS design and fabrication encounter...
Show moreAs the feature size of silicon semiconductor devices scales down to nanometer range, planar bulk CMOS design and fabrication encounter significant challenges. This situation is exacerbated when it comes to SRAM, as SRAM takes a large part of power consumption and area overhead in modern VLSI processor designs. To achieve higher performance, stability and lower power consumption, carbon nanotube (CNT) has been introduced to SRAM design as an alternative material. The semiconducting single-walled CNTs are promising candidates for the channel material of CMOS devices because of two advantages over the other semiconductor materials: high ON current, leading to high speed and low OFF current, leading to less leakage power. In this research work, characterizing work of technology parameters for 6T carbon nanotube field effect transistor (CNFET) SRAM cell is performed for basic understanding of the relationship between SRAM delay/power and CNFET technology parameters. Stability issue is studied by investigating the diameter and transistor ratio impacts on the SRAM static noise margin (SNM). A stability-optimized 6T CNFET SRAM cell achieves 38.88% reading delay reduction, 21.61% writing delay reduction, 85.65% reading power reduction, 5.88% writing power reduction, 97.80% leakage power reduction, 41.41% SNM increment, 91.23% reading power-delay product (PDP) reduction and 26.23% writing PDP reduction, compared with conventional silicon MOSFET SRAM cell. To mitigate major CNT imperfection impacts on CNFET circuits, a misalignment immune SRAM design method is proposed to eliminate CNT misalignment problem by using etching region defined in circuit layout; and a diameter variation sensing and compensating system is designed to mitigate the negative impacts of CNT diameter variation on SRAM delay and power consumption. A hybrid silicon/CNT 4T SRAM cell design is proposed for low-power high-density cache application, which is better than conventionally used 6T SRAM in terms of power consumption and circuit area. Finally, a design flow of high performance, high stability and low power SRAM is summarized.
Ph.D. in Electrical Engineering, July 2012
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- Title
- Test of a new type of storage cell
- Creator
- Allyn, A. J., Torrance, R. S.
- Date
- 2009, 1906
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/testofnewtypeofs00ally
Thesis (B.S.)--Armour Institute of Technology
- Title
- New Housing Model "Flexible Housing Components": Final Booklet_05-02-12
- Creator
- Quinn, Aidan
- Date
- 2012-05-02, 2012-05
- Description
-
This project is a focus on spatial flexibility. The idea is to generate housing components that focuses on flexibility in order to create...
Show moreThis project is a focus on spatial flexibility. The idea is to generate housing components that focuses on flexibility in order to create space that is defined by the user.
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- Title
- Transducer System Having a Series of Cores with First and Second Windings with A.C. Signals Applied Thereto
- Creator
- Camras, Marvin
- Date
- 4/24/2009, 1970-01-06
- Description
-
Sponsorship: IIT Research Institute
United States Patent
- Title
- Cross Field Transducer Head with Housing as Cross Field Return Path
- Creator
- Camras, Marvin
- Date
- 4/24/2009, 1970-05-19
- Description
-
Sponsorship: IIT Research Institute
United States Patent
- Title
- Magnetic Recorder Sound Unit
- Creator
- Camras, Marvin
- Date
- 1958-06-24
- Description
-
Sponsorship: Armour Research Foundation of Illinois Institute of Technology
United States Patent
- Title
- Method and Means of Magnetic Recording
- Creator
- Camras, Marvin
- Date
- 1944-06-13
- Description
-
Sponsorship: Armour Research Foundation
United States Patent
- Title
- Winding and Reeling Mechanism
- Creator
- Zenner, Raymond E.
- Date
- 1954-04-13
- Description
-
Sponsorship: Armour Research Foundation of Illinois Institute of Technology
United States Patent
- Title
- DYNAMICS OF A THREE-DIMENSIONAL FOUR-BAR LINKAGE SUBJECT TO RANDOM EXTERNAL FORCING
- Creator
- Lytell, Mark R.
- Date
- 2011-11-15, 2011-12
- Description
-
This thesis explores the dynamics of a three-dimensional four-bar mechanical linkage subject to random external forcing. The Lagrangian...
Show moreThis thesis explores the dynamics of a three-dimensional four-bar mechanical linkage subject to random external forcing. The Lagrangian formulation of the equations of motion are index-3 stochastic di erential-algebraic equations (SDAE) that describe the time evolution of the sample paths of the generalized coordinates, velocities, and Lagrange multipliers as stochastic processes. We solve the SDAEs using two di erent approaches: inverse dynamics, Case Study 1, via independent, successive solution of the nonlinear equations for each kinematic variable, where the time evolution of one generalized coordinate is prescribed; and direct dynamics, Case Study 2, via direct solution of the SDAEs in the index-1 formulation, using fourth-order stochastic backward di erentiation formula (BDF) with modi ed Newton iteration and position and velocity stabilization (Ascher and Petzold [2]), where the (deterministic) input driving torque is prescribed. For the particular application of a three-dimensional swing gate security system, we conduct numerical experiments for both approaches. In Case Study 1, we simulate the random external forcing as a Gaussian wind speed process that applies stochastic wind drag onto the gate. The kinematic variables are deterministic, while the required input driving torque is a stochastic process. In Case Study 2, we apply the external forcing as a resistive torque with additive Gaussian noise modeling the wind drag; the kinematic variables are stochastic processes. For both cases, we apply four mean wind speeds: 0 mph (deterministic only), 10 mph, 20 mph, and 30 mph, from which we compute the deterministic solution and three stochastic sample paths for each stochastic process. The overall conclusions are that direct solution is possible for inverse dynamics, that the solution of index-1 SDAEs in multibody dynamics is tractable since the mass matrix is symmetric and positive de nite, and that the deterministic solution is the expectation of the sample paths.
M.S. in Applied Mathematics, December 2011
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