Radionuclide therapy using I-131-labeled anti-epidermal growth factor receptor-targeted nanoparticles suppresses cancer cell growth caused by EGFR overexpression

Introduction Anti-epidermal growth factor receptor (EGFR)-targeted nanoparticles can be used to deliver a therapeutic and imaging agent to EGFR-overexpressing tumor cells. I-131-labeled anti-EGFR nanoparticles derived from cetuximab were used as a tumor-targeting vehicle in radionuclide therapy

Towards a Systematic Exploration of the Optimization Space for Many-Core Processors

The architecture diversity of many-core processors - with their different types of cores, and memory hierarchies - makes the old model of reprogramming every application for every platform infeasible. Therefore, inter-platform portability has become a desirable feature of programming models. While functional portability is ensured by standards and compilers (e.g., OpenCL), to achieve high performance across platforms remains a much more challenging task. In this thesis, we have investigated the enabling/disabling techniques for platform-specific optimizations with a unified programming model. We have selected OpenCL as our research vehicle, and identified that each platform has a specific optimization space for a given kernel. Taking two concrete examples, we have proposed solutions on how to (semi-) automatically tackle platform-specific optimizations with a unified programming model. We use a case study (in computer vision) to illustrate optimization’s dependency on platform. To deal with the difference in processing cores, we propose two approaches to vectorize scalar kernels (i.e., explicitly using vector data types), and reveal the vectorization needs with explicitly parallel programs. To deal with the difference in memory hierarchy, we first present a method to quantify the performance impact of using local memory starting from the memory access patterns. This work produces a performance database, which serves as an indicator of whether using local memory is beneficial. Once this indication is given, we propose a portable solution to simplify programming with local memory. Specifically, we present an easy-to-use API (ELMO) to enable local memory usage and a compiling pass (Grover) to automatically disable the local memory usage for applications where local memory is natively used. Much like vectorization and local memory usage, other architectural features require performance portable approaches. Therefore, we present our vision for a portable programming framework, called SESAME, which expands to architectural features beyond SIMD units and local memory. This thesis has given evidence that this problem can be addressed successfully. We conclude that tools such as SESAME help improving the state-of-the-art of existing programming models (like OpenCL, in our case) and ease the task of programmers when dealing with different many-core architectures. This work serves an essential step towards portable performance by systematically exploring the optimization space.Department of Software and Computer TechnologyElectrical Engineering, Mathematics and Computer Scienc

Database Acceleration on FPGAs

Though field-programmable gate arrays (FPGAs) have been used to accelerate database systems, they have not been widely adopted for the following reasons. As databases have transitioned to higher bandwidth technology such as in-memory and NVMe, the communication overhead associated with accelerators has become more of a burden. Also, FPGAs are more difficult to program, and GPUs have emerged as an alternative technology with better programming support. However, with the development of new interconnect technology, memory technology, and improved FPGA design tool chains, FPGAs again provide significant opportunities. Therefore, we believe that FPGAs can be attractive again in the database field. This thesis focuses on FPGAs as a high-performance compute platform, and explores using FPGAs to accelerate database systems. It investigates the current challenges that have held FPGAs back in the database field as well as the opportunities resulting from recent technology developments. The investigation illustrates that FPGAs can provide significant advantages for integration in database systems. However, to make further progress, studies in a number of areas, including new database architectures, new types of accelerators, deep performance analysis, and the development of the tool chains are required. Our contributions focus on accelerators for databases implemented in reconfigurable logic. We provide an overview of prior work and make contributions to two specific types of accelerators: both a compute-intensive (decompression) and a memory-intensive (hash join) accelerator.SIKS Dissertation Series No. 2019-37Computer Engineerin

Additively manufactured scaffolds for bone tissue engineering and the prediction of their mechanical behavior: A review

Additive manufacturing (AM), nowadays commonly known as 3D printing, is a revolutionary materials processing technology, particularly suitable for the production of low-volume parts with high shape complexities and often with multiple functions. As such, it holds great promise for the fabrication of patient-specific implants. In recent years, remarkable progress has been made in implementing AM in the bio-fabrication field. This paper presents an overview on the state-of-the-art AM technology for bone tissue engineering (BTE) scaffolds, with a particular focus on the AM scaffolds made of metallic biomaterials. It starts with a brief description of architecture design strategies to meet the biological and mechanical property requirements of scaffolds. Then, it summarizes the working principles, advantages and limitations of each of AM methods suitable for creating porous structures and manufacturing scaffolds from powdered materials. It elaborates on the finite-element (FE) analysis applied to predict the mechanical behavior of AM scaffolds, as well as the effect of the architectural design of porous structure on its mechanical properties. The review ends up with the authors’ view on the current challenges and further research directions.Biomaterials & Tissue Biomechanic

Physical simulation method for the investigation of weld seam formation during the extrusion of aluminum alloys

Extrusion through the porthole die is a predominant forming process used in the production of hollow aluminum alloy profiles across the aluminum extrusion industry. Longitudinal weld seams formed during the process may negatively influence the quality of extruded profiles. It is therefore of great importance to understand the formation of weld seams inside the welding chamber during extrusion, as affected by extrusion process variables and die design. Previously developed physical simulation methods could not fully reproduce the thermomechanical conditions inside the welding chamber of porthole die. In this research, a novel physical simulation method for the investigation of weld seam formation during extrusion was developed. With a tailor-designed tooling set mounted on a universal testing machine, the effects of temperature, speed, and strain on the weld seam quality of the 6063 alloy were investigated. The strains inside the welding chamber were found to be of paramount importance for the bonding of metal streams, accompanied by microstructural changes, i.e., recovery or recrystallization, depending on the local deformation condition. The method was shown to be able to provide guidelines for the design of porthole dies and choice of extrusion process variables, thereby reducing the scrap rate of aluminum extrusion operation.Accepted Author ManuscriptBiomaterials & Tissue Biomechanic

Construction of three-dimensional extrusion limit diagram for magnesium alloy using artificial neural network and its validation

Conventional extrusion limit diagram (ELD) involves only two extrusion process variables and as such it does not account for the combined effects of multiple process parameters on the extrusion process with respect to pressure requirement and extrudate temperature. Attempts were made in the present research to construct three-dimensional (3D) ELD for a magnesium alloy in the space of initial billet temperature, extrusion ratio and extrusion speed. A method to build 3D ELD by integrating finite element (FE) simulations, extrusion experiments and artificial neural networks (ANN) was developed. In addition to initial billet temperature, extrusion ratio and extrusion speed, the temperature difference between the extrusion tooling and billet, the size of the billet and the shape complexity of the extrudate were taken as the additional process variables and integrated into the equivalent initial billet temperature, extrusion ratio and extrusion speed. The FE simulations, verified by performing extrusion experiments to produce magnesium alloy rods, were used to generate datasets for training the ANN. The ANN then predicted the peak values of extrusion pressure and extrudate temperature over a wider range of extrusion conditions, based on which a 3D ELD for the magnesium alloy was constructed. The 3D ELD was finally validated by performing extrusion experiments to produce magnesium alloy tubes. The results demonstrated that the constructed 3D ELD was reliable and able to provide guidelines for the selection of appropriate extrusion conditions.Accepted Author ManuscriptBiomaterials & Tissue Biomechanic

Investigation into the extrudability of a new Mg-Al-Zn-RE alloy with large amounts of alloying elements

The present study was aimed at determining the extrudability of a newly developed Mg-Al-Zn-RE magnesium alloy with large amounts of alloying elements. The experimental and numerical investigation clearly showed that the extrudate temperature was a crucial factor in deciding if a critical temperature between 754 K and 768 K (481 °C and 495 °C) was reached during extrusion, above which hot shortness occurred. Under the extrusion conditions applied, dynamic recrystallization (DRX) occurred, leading to grain refinement from a mean grain size of 165 μm in the as-solid-solution-treated billet to 8.0 to 10.9 μm in the extruded rods. Second-phase particles, such as Mg17Al12 and Al11La3, were found to distribute on grain boundaries and aid in grain refinement. The mechanical properties of the extrudate were greatly influenced by the as-extruded microstructure and extrusion condition. As the initial billet temperature decreased, the ultimate tensile strength (UTS) and elongation of the alloy increased, while yield strength (YS) remained almost unchanged. At an initial billet temperature of 523 K (250 °C), a stem speed of 3.93 mm/s, and a reduction ratio of 29.8, the extruded magnesium alloy had a mean grain size of 8 μm. Its YS, UTS, and elongation reached 217 ± 3 MPa, 397 ± 7 MPa, and 20 ± 1.3 pct, respectively.Accepted Author ManuscriptBiomaterials & Tissue Biomechanic

Integrated physical and numerical simulations of weld seam formation during extrusion of magnesium alloy

Solid-state bonding takes place during the extrusion process to produce a hollow metal profile through a porthole die, known as extrusion welding. Defective weld seams degrade extruded products in mechanical properties. The present research was aimed to determine the effect of extrusion condition on the longitudinal weld seam quality of a magnesium alloy, Mg-8Al-0.5Zn-0.5RE, using an integrated physical and numerical simulation method. A special die set-up for physical simulation was designed, through which two magnesium alloy rods were welded in the solid-state under high hydrostatic pressure. Extrusion welding experiments under different conditions were performed. It was demonstrated that, with this die set-up, the formation of weld seams during extrusion to produce hollow profiles could be physically simulated. The extrusion welding experiments were then numerically simulated to reveal strains, stresses and hydrostatic pressures that could not be experimentally measured. Finally, the tensile strength and elongation of the extrusion-welded magnesium alloy were determined and its microstructure was examined. The results showed that the bonding strength increased with decreasing extrusion speed and rising extrusion temperature. For well-bonded rods, weld seam was invisible under optical microscope. Attributed to high temperature and large equivalent strain, complete dynamic recrystallization occurred across the interface, leading to a reduced average grain size and disappearance of weld seam. By applying the integrated physical and numerical simulation method, extrusion process parameters for a particular magnesium alloy can be optimized to ensure weld seam quality of extruded hollow profiles.Accepted Author ManuscriptBiomaterials & Tissue Biomechanic

Analysis of the bonding strength and microstructure of AA6082 extrusion weld seams formed during physical simulation

The research was aimed to determine the effects of extrusion process condition on the weld seam quality of the aluminum alloy AA6082 by using a novel physical simulation method. A weld seam between two bars was formed under hydrostatic pressure in a specially designed die setup to simulate the longitudinal weld seam formation during extrusion through porthole die. With this die setup, extrusion process variables, i.e., temperature, extrusion speed and strain, could be varied so that their individual effects on weld seam quality could be discriminated. With the help of finite element (FE) simulation, the distributions of strains, strain rates and hydrostatic pressures inside the welding chamber were quantified. Tension tests were performed to evaluate the bonding strengths of solid-state welded samples. It was found that the amount of deformation imposed inside the welding chamber had a dominant effect on the bonding strength. A high deformation temperature and a high extrusion speed enhanced the bonding strength. The microstructures across the weld zone were examined by using a polarized light microscope and electron back-scatter diffraction (EBSD). The microstructure evolutions inside and around the welding zone were found to be influenced by the deformation condition. High temperature, high extrusion speed and large deformation promoted the occurrence of local dynamic recrystallization, leading to reduced mean grain sizes inside the welding zone, corresponding to an enhanced strength at the weld seam.Biomaterials & Tissue Biomechanic

Counterfeit construction products from low-cost sourcing countries

Counterfeiting has been around since ancient times. Counterfeiting in modern times was once widespread and not confined to any geographic region. With the globalization efforts following World War II, counterfeiting became an international problem, much of it emanating from Japan\u92s developing manufacturing-based economy. As Japan\u92s economy matured in the late 1960s, the epicenter of the counterfeiting industry moved to Korea. As Korea\u92s economy improved, the bulk of the problem moved to China, where it resides today. A research project was funded by the Construction Industry Institute in Austin, TX to answer four questions: 1) Has the worldwide counterfeiting problem extended into construction materials, equipment and other products?; If so, how large is the problem?; If so, what countries or regions are the source of the counterfeit goods?; If so, what countries or regions are the destination of the counterfeit goods? Results showed that counterfeiting of construction goods is a problem that the problem is large and dangerous, that, like counterfeiting as a whole, China is the primary source of counterfeit construction goods, and the destination of the counterfeit goods is most often the U.S., but can be any place that the counterfeiter thinks that a profit can be made. The team was also asked to make recommendations to industry to mitigate the problem