Novel Biocompatible/Antimicrobial Materials Based on Nitric Oxide Release/Generation.

Thrombus formation and bacterial infection are two major problems that are associated with indwelling biomedical devices. In this dissertation work, coatings that are capable of releasing or generating nitric oxide (NO), a potent anti-platelet and antimicrobial agent, have been developed to solve the biocompatibility issues. First, diazeniumdiolate doped-poly(lactic-co-glycolic acid) (PLGA)-based NO release coatings with controllable NO release profiles can be prepared with lifetimes of up to 15 d at room temperature and 10 d at 37°C. The NO release coatings exhibit significant antibiofilm properties after one week incubation in a CDC biofilm reactor, which provided both renewable nutrient sources and shear forces. In particular, compared to a silicone rubber surface, an NO release film with a base layer of 30 wt% dibutyhexyldiamine diazeniumdiolate (DBHD/N2O2) mixed with poly(lactic acid) (PLL) exhibited ~ 98.4% reduction in biofilm biomass of S. aureus and ~ 99.9% reduction for E. coli at 37 °C. NO can also be generated from endogenous NO donors such as S-nitrosothiols (RSNOs) by utilizing catalytic materials. A carboxyl-ebselen-based layer-by-layer (LbL) film was fabricated by alternatively assembling carboxyl-ebselen linked polyethylenimine (e-PEI) and alginate (Alg) onto substrates followed by salt annealing and cross-linking. After soaking in sheep blood for 24 h, a polyurethane catheter coated with (e-PEI/Alg)50 exhibit an NO flux of 3×10-10 mol cm-2 min-1 in a reservoir containing physiological levels of RSNO and thiols. The LbL film is also capable of generating superoxide, a potent antimicrobial agent. In-vitro antimicrobial tests demonstrated that a (e-PEI/Alg)50 film is capable of killing 98.2 % E. coli in solution and reducing ~87% E. coli surface coverage within 2 h at 37°C. In addition, a novel CuO nanoparticle-doped polyurethane film with less leaching of copper and minimized toxicity issue compared with a similar film doped with Cu nanoparticles is prepared. The film is capable of catalytically generating NO for 16 days at 37 °C. With their proven potential antithrombotic or antimicrobial properties, the developed NO release and NO generation coatings are expected to improve the biocompatibility of indwelling surfaces, reduce the medical cost and save patients’ lives.PHDChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/100090/1/wenyicai_1.pd

Case Assignment: A Comparison between Agreement-based versus Dependent Case Accounts

This major research paper (MRP) aims to review the literature that has looked into Case theories from a generative grammar perspective from Government and Binding (Chomsky, 1981) onwards. Specifically, it offers a critical examination of the agreement-based Case account (Chomsky, 1981, 1995, 2000, 2001, etc.) and the dependent Case account (Marantz, 1991), and discusses their contribution to our current understanding of syntactic Case valuation on nominal arguments. Various counterevidence is also presented, which raises potential problems for both accounts

Robust prior-based single image super resolution under multiple Gaussian degradations

Although SISR (Single Image Super Resolution) problem can be effectively solved by deep learning based methods, the training phase often considers single degradation type such as bicubic interpolation or Gaussian blur with fixed variance. These priori hypotheses often fail and lead to reconstruction error in real scenario. In this paper, we propose an end-to-end CNN model RPSRMD to handle SR problem in multiple Gaussian degradations by extracting and using as side information a shared image prior that is consistent in different Gaussian degradations. The shared image prior is generated by an AED network RPGen with a rationally designed loss function that contains two parts: consistency loss and validity loss. These losses supervise the training of AED to guarantee that the image priors of one image with different Gaussian blurs to be very similar. Afterwards we carefully designed a SR network, which is termed as PResNet (Prior based Residual Network) in this paper, to efficiently use the image priors and generate high quality and robust SR images when unknown Gaussian blur is presented. When we applied variant Gaussian blurs to the low resolution images, the experiments prove that our proposed RPSRMD, which includes RPGen and PResNet as two core components, is superior to many state-of-the-art SR methods that were designed and trained to handle multi-degradation

Progression of the PI3K/Akt signaling pathway in chronic obstructive pulmonary disease

Chronic Obstructive Pulmonary Disease (COPD) is a chronic respiratory disease characterized by a slow progression and caused by the inhalation of harmful particulate matter. Cigarette smoke and air pollutants are the primary contributing factors. Currently, the pathogenesis of COPD remains incompletely understood. The PI3K/Akt signaling pathway has recently emerged as a critical regulator of inflammation and oxidative stress response in COPD, playing a pivotal role in the disease’s progression and treatment. This paper reviews the association between the PI3K/Akt pathway and COPD, examines effective PI3K/Akt inhibitors and novel anti-COPD agents, aiming to identify new therapeutic targets for clinical intervention in this disease

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Composition and Thermal Structure of the Upper Troposphere and Lower Stratosphere in a Penetrating Mesoscale Convective Complex Determined by Satellite Observations and Model Simulations

We describe here the composition and thermal structure of the upper troposphere and lower stratosphere during a penetrating mesoscale convective complex (MCC) event that occurred in southern China on 8 June 2009. Our results are based on satellite observations and Weather Research and Forecasting model simulations. Ice-rich and ozone-poor air reached as high as 17 km. The air was −5°C colder inside the mature MCC than outside at the first cold-point tropopause near 17 km, −2°C colder inside the mature MCC than outside at the second cold-point tropopause, and 3°C warmer inside the mature MCC than outside between the two cold-point tropopauses. Corresponding to the temperature structure, there were two lower water vapor contents inside the MCC than outside near 17 km and 19 km while there was a higher water vapor content inside the MCC than outside near 18 km