High aspect ratio silicon dioxide-coated single-walled carbon nanotube scanning probe nanoelectrodes

We have fabricated high aspect ratio, hydrophilic nanoelectrodes from individual single-walled carbon nanotubes (SWNTs) mounted on conductive atomic force microscope (AFM) tips for use as electrochemical probes. Individual SWNTs with an average diameter of 5 nm and up to 1.5 μm in length were passivated with nanometer-thick SiO_2 films, deposited conformally in an inductively coupled plasma reactor. The electrically insulating SiO_2 films improved the nanotube rigidity and stabilized the nanotube−AFM tip contact to enable use in aqueous environments. The nanotube tip was successfully exposed by subjecting the probe to nanosecond electrical pulse etching but only after electron beam irradiation in a transmission electron microscope (TEM). Probe functionality was verified by electrodepositing gold nanoparticles from aqueous solution only at the exposed tip

Resveratrol protects the retina from I/R injury by inhibiting RGCS apoptosis, glial activation and expression of inflammatory factors

Purpose: To study the protective effect of resveratrol against retinal injury induced by ischemiareperfusion (I/R), and the underlying mechanism  action.Methods: Retinal I/R injury was established in 72 healthy male SD rats. The rats were assigned to 3 groups: control, model and resveratrol groups, with 24 rats in each group. Pathological changes in retina were determined using H&E staining. Retinal ganglion cells (RGCs) were counted usingfluorescence gold retrograde staining. Western blotting was used to assay the expressions of caspase- 3, Bax, Bcl-2, GFAP, COX-2 and iNOS. The expressions of COX-2 and iNOS were measured by immunofluorescence.Results: The retina in the control group was dense and ordered, and its morphology was normal. In contrast, the retina in the model group was thinner, with loose cells and disordered structure. In the resveratrol group, the retina was thicker, the structure was orderly, and the cells were dense. Relative to control, the population of RGCs in model rat retina was significantly reduced, and the expressions of Bcl-2, Bax, caspase-3, GFAP, COX-2 and iNOS were significantly upregulated (p < 0.05). In the resveratrol group, the number of RGCs in the retina was markedly elevated, relative to model rats, and the expressions of Bcl-2, Bax, caspase-3, GFAP, COX-2 and iNOS were significantly decreased (p < 0.05).Conclusion: Resveratrol protects the retina from I/R injury in rats by inhibiting RGCs apoptosis, glial activation and expressions of inflammatory factors. Thus, this compound may be potentially suitable for the management of retina damage. Keywords: Resveratrol, RGCs apoptosis, Glial activation, Inflammatory factors, I/R injur

Conventional and unconventional monetary policy in a DSGE model with an interbank market friction

This thesis examines both conventional and unconventional monetary policies in a DSGE model with an interbank market friction. The recent crisis during 2007-2009 affected economies worldwide and forced central banks to implement not just conventional monetary policies, but also direct interventions in financial markets. We investigate a DSGE model with financial frictions, to test conventional and unconventional monetary policies. The thesis starts by using the Gertler and Kiyotaki (2010)’s modelling framework, to examine eight different shocks under imperfect interbank market conditions. Unlike Gertler and Kiyotaki (2010) who consider the two extreme cases for the banking system, I firstly extend the analysis to a case in between the two extreme cases that they examined. The shocks considered include supply and demand shocks and also two shocks from the financial system itself (an interbank market shock and a shock to the deposit market). It is found that a negative shock to the interbank market has only a moderate impact to the banking system. However, a shock to the deposit market has a much stronger impact. Even though the impacts of these shocks are not large it is shown that thefinancial frictions magnify the effects of other shocks. The model is extended to include price stickiness. A modified Taylor rule is analysed to test how conventional monetary policy should respond to the shocks in the presence of financial frictions. Specifically the credit spread is added as a third term in the monetary policy rule. The stabilising properties of the policy rule are analysed and a welfare analysis is conducted. The model is further developed to include unconventional monetary policy in the form of direct lending to private sector firms from the central bank. A policy rule for unconventional policy is tested and its stabilising and welfare properties are analysed

Design of High Throughput Reconfigurable LDPC CODEC

Channel coding is an essential part of communication systems, which significantly reduces the error rate of receiving messages. Nowadays, iterative decoding methods play an important role in wireless communication such as 5G, Wi-Fi etc. Low-Density Parity-Check (LDPC) codes are one of the most used iterative decoding codes, which attract lots of interest in a wide range of applications. LDPC codes have a channel approaching capacity, which is practical for implementation as well. The thesis focuses on the design of high throughput reconfigurable LDPC channel codec with good performance. The main focus of this thesis is the design of a novel decoding algorithm for LDPC codes. The new decoding algorithm is configurable to adjust its performance and complexity, which is very flexible for applications. Its error correction capability is close to the sum-product algorithm but with significantly lower complexity. We further implement the LDPC encoder/decoder on FPGA, which is reconfigurable for 5G NR or user-defined LDPC codes. In particular, we apply the new decoding algorithm to the decoder and analyse its performance on hardware. Moreover, we compared the error detection performance of 5G NR CRC and LDPC Syndrome to investigate the necessity of using CRC decoding or LDPC syndrome check, or both in practical systems. At last, a 5G NR physical layer simulating SoC embedded system is built on FPGA for the verification of the encoder and decoder

Penalized regression for predicting phenotypes in the Collaborative Cross

The Collaborative Cross (CC) are a set of recombinant inbred laboratory mouse strains whose genotype data are designed to have a natural grouping structure. Given a set of quantitative phenotype data of a subset of genotyped CC strains, we want to train a model that can predict phenotype values of the CC strains for which the data for this phenotype is missing. In genetic studies, linear models are generally used to relate the genotypes to the phenotypes. However, the solution to a simple linear regression with high dimensional genomic data is often undefined. In this case, penalized regressions are applied to eliminate variables with little predictive strength. We designed a series of cross-validated tests to explore the prediction performances of different penalized regression approaches on the CC data. We found that lasso and the group lasso lead to lower mean cross-validated sum of squared errors when used with the optimal tuning parameters. However, in most cases, both methods failed to find a set of predictors that significantly outperforms the intercept-only model.Bachelor of Science in Public Healt