On-line coupling of capillary electrophoresis and liquid chromatography with electrospray ionization mass spectrometry for protein characterization

On-line coupling of capillary isoelectric focusing (CIEF) and liquid chromatography (LC) with electrospray ionization mass spectrometry (ESIMS) is utilized for protein characterization;A microdialysis junction, based on a microdialysis membrane connecting both a separation capillary and a short, sharply tapered microelectrospray emitter capillary, is demonstrated for CIEF-ESIMS. Besides the electrical connection across the microdialysis junction, post-run acidification via the dialysis membrane is demonstrated for enhancing the protonation and the ionization efficiency of focused proteins while maintaining separation efficiency, resolution, and sensitivity in CIEF-ESIMS;On-line combination of CIEF with ESI-FTICRMS is demonstrated for high resolution analysis of model proteins, human hemoglobin variants, and Escherichia coli proteins. The acquisition of high-resolution mass spectra of hemoglobin [beta] chains allows direct identification of hemoglobin variants A and C, differing in molecular mass by 1 dalton. Direct mass determination of cellular proteins separated in the CIEF capillary is achieved using their isotopic envelopes obtained from ESI-FTICRMS;An integrated approach, involving the combination of exoglycosidase enzyme array with LC/MS/MS, is demonstrated for structural analysis of carbohydrate moieties of glycopeptides from a glycoprotein digest. The molecular mass information from a series of controlled digestions together with specific compositions of exoglycosidases in the enzyme array provide the sequence and linkage of individual glycan species attached to glycopeptides and glycoproteins

Bond Issuance mechanisms and their effects on revenues

This thesis consists of three essays on the discussion about superiority among different government security issuance mechanisms: book-building, discriminatory auctions, and uniform auctions. Using a large Chinese government primary and secondary bond market data set, I analyse the revenue rankings of these mechanisms. Results suggest that uniform auctions are superior to book building and discriminatory auctions in generating revenues. Further, results suggest that uniform auctions are better in mitigating bond losses compared to discriminatory auctions. The first essay compares the primary rate between book building and uniform auctions, using data from Chinese local government bonds. Results show that book building procedures lead to a higher primary rate than uniform auction procedures, which reduces the issuers' revenue. These findings are robust across different revenue measurements: primary rates, primary rates normalized by T-bond daily yield rate one day prior to issuance day and primary rates normalized by five days' average T-bond daily yield rate before issuance day. Therefore, uniform auctions generate higher income than book building. The second essay exploits a large-size auction experiment conducted by two Chinese Government bond issuers-the Chinese Development Bank and the Export-Import Bank-to investigate whether Treasury securities should be sold through uniform or discriminatory auction mechanisms. Based on the outcomes of more than 300 Treasury securities issued through an alternating auction-rule market experiment, the study finds that auction outcome yield rates of the two auction formats are not statistically different. Further, these estimates indicate that there is no significant economic difference in terms of revenue between the two auction mechanisms. This result is robust across different bond-yield rate measurements and participation behaviour. The third essay documents the existence of primary dealers' losses in Treasury bond markets and investigates how these losses affect dealers' market value. Using a novel data set that tracks more than 2,350 primary-to-secondary transactions, the study finds that bond losses for primary dealers are prevalent and were severe during the financial crisis. Results indicate that liquidity constraints are a major source of bond losses observed in primary-to-secondary trades. Results also find that financial sector value is correlated with these losses. Using an alternating market experiment, the study shows that bond losses are higher under discriminatory auctions as compared to uniform auctions

End-of-Life and Constant Rate Reliability Modeling for Semiconductor Packages Using Knowledge-Based Test Approaches

End-of-life and constant rate reliability modeling for semiconductor packages are the focuses of this dissertation. Knowledge-based testing approaches are applied and the test-to-failure approach is approved to be a reliable approach. First of all, the end-of-life AF models for solder joint reliability are studied. The research results show using one universal AF model for all packages is flawed approach. An assessment matrix is generated to guide the application of AF models. The AF models chosen should be either assessed based on available data or validated through accelerated stress tests. A common model can be applied if the packages have similar structures and materials. The studies show that different AF models will be required for SnPb solder joints and SAC lead-free solder joints. Second, solder bumps under power cycling conditions are found to follow constant rate reliability models due to variations of the operating conditions. Case studies demonstrate that a constant rate reliability model is appropriate to describe non solder joint related semiconductor package failures as well. Third, the dissertation describes the rate models using Chi-square approach cannot correlate well with the expected failure mechanisms in field applications. The estimation of the upper bound using a Chi-square value from zero failure is flawed. The dissertation emphasizes that the failure data is required for the failure rate estimation. A simple but tighter approach is proposed and provides much tighter bounds in comparison of other approaches available. Last, the reliability of solder bumps in flip chip packages under power cycling conditions is studied. The bump materials and underfill materials will significantly influence the reliability of the solder bumps. A set of comparable bump materials and the underfill materials will dramatically improve the end-of-life solder bumps under power cycling loads, and bump materials are one of the most significant factors. Comparing to the field failure data obtained, the end-of-life model does not predict the failures in the field, which is more close to an approximately constant failure rate. In addition, the studies find an improper underfill material could change the failure location from solder bump cracking to ILD cracking or BGA solder joint failures

Motorized Wireless-Charging Pad that Uses Magnetic Field Detection

This publication describes a motorized wireless power transfer (WPT) system (e.g., motorized Qi charger) that utilizes tunnel magnetoresistance (TMR) to automatically laterally and vertically align the transmitter (Tx) of the WPT system to the receiver (Rx) of a user equipment (UE), such as a smartphone, earphones, a smartwatch, and so forth. The WPT system has TMR sensors that utilize magnetic tunnel junction (MTJ) elements that exhibit low magnetic hysteresis and high magnetoresistance sensitivity to a change in the magnetic field. An array of TMR sensors can be used to reliably detect the magnetic field distribution and can detect the lateral, vertical alignment, and/or misalignment between the Tx of the WPT system and the Rx of the UE. The exact number and spatial arrangements of the TMR sensors may differ depending on the shape and size of the charging pad of the WPT system. The WPT system may have one, two, three, and so forth, transmitters sitting on top of one, two, three, and so forth, motorized arms that enable the WPT system to automatically laterally and/or vertically align to and charge one, two, three, and so forth, UE at the same time. The described WPT system can support different-size UE, can wirelessly charge multiple UE at the same time, increases the coupling coefficient, increases the transferred-power efficiency, decreases power loss, decreases charging time, may mitigate damages to the UE and the WPT system caused by thermal energy, enhances user experience, and enables a user to use electric energy more efficiently

Modeling Three-dimensional Invasive Solid Tumor Growth in Heterogeneous Microenvironment under Chemotherapy

A systematic understanding of the evolution and growth dynamics of invasive solid tumors in response to different chemotherapy strategies is crucial for the development of individually optimized oncotherapy. Here, we develop a hybrid three-dimensional (3D) computational model that integrates pharmacokinetic model, continuum diffusion-reaction model and discrete cell automaton model to investigate 3D invasive solid tumor growth in heterogeneous microenvironment under chemotherapy. Specifically, we consider the effects of heterogeneous environment on drug diffusion, tumor growth, invasion and the drug-tumor interaction on individual cell level. We employ the hybrid model to investigate the evolution and growth dynamics of avascular invasive solid tumors under different chemotherapy strategies. Our simulations reproduce the well-established observation that constant dosing is generally more effective in suppressing primary tumor growth than periodic dosing, due to the resulting continuous high drug concentration. In highly heterogeneous microenvironment, the malignancy of the tumor is significantly enhanced, leading to inefficiency of chemotherapies. The effects of geometrically-confined microenvironment and non-uniform drug dosing are also investigated. Our computational model, when supplemented with sufficient clinical data, could eventually lead to the development of efficient in silico tools for prognosis and treatment strategy optimization.Comment: 41 pages, 8 figure

Bond Losses and Systemic Risk

This paper documents the existence of primary dealers' losses in Treasury bond markets and investigates how these losses affect dealers' market value. Using a novel data set that tracks more than 2,350 primary-to-secondary transactions, we find that bond losses for primary dealers are prevalent and were severe during the financial crisis. Our results indicate that liquidity constraints are a major source of bond losses observed in primary-to-secondary trades. We also find that financial sector value is correlated with these losses. Using an alternating market experiment, we show that bond losses are higher under discriminatory auctions as compared to uniform auctions

Motorized coil wireless charger with computer vision assisted alignment

This disclosure describes techniques for a wireless charger to identify a device e.g., smartphone, wireless headset, smartwatch etc. that is placed on a charging surface and to automatically align the transmitter coil to the exact location of the receiver coil. When a device is placed on charging surfaces, cameras on the wireless charger captures images of the device. The image is processed to construct a three-dimensional model and identify the exact model of the device to determine the location of the receiver coil within the device relative to the charging surface. When the location of the receiver coil is determined, the transmitter coil is aligned by use of motorized arms and coils to achieve optimal charging performance and efficiency

Motorized coil wireless charger with coil alignment mechanism

The disclosure describes techniques to improve power transfer efficiency of a wireless charger through a coil alignment mechanism. A transmitter coil of a wireless charger is configured with step motors and gears, and can travel in a radial motion and towards or away from a central point to align with the receiver coil of a device across the charging surface. Further, the transmitter coil can also be moved in a direction perpendicular with respect to the charging surface which can help optimize the distance from the receiver coil. Charging efficiency and stability between the transmitter and receiver coils are measured using signal strength of packets