Polymeric micelles for the dispersal of infectious biofilms

Multi-drug resistance amongst pathogenic bacteria is becoming a growing threat to human health. A factor contributing to the recalcitrance of infectious bacteria is their growth in a biofilm. Biofilms protect bacteria against antibiotics and host immune cells. As a part of the biofilm cycle of life, bacteria can be dispersed from biofilms to initiate colonization elsewhere after circulating through the blood. During this stage, bacteria are more susceptible to antibiotics and immune cells compared with their counterparts living in a biofilm. Accordingly, biofilm dispersal initiated by synthetically derived dispersants is regarded more and more as an emerging strategy to combat biofilm-related infections in combination with or without the use of existing antibiotics. In this thesis, we have developed novel nanoparticles that function as synthetic dispersants or enable targeted delivery of dispersants to infectious biofilms. Precise delivery is envisioned to balance dispersal with the ability of the immune system to deal with dispersed bacteria to avoid the concurrent use of antibiotics or enhance concurrent antibiotic killing. A dispersal index was introduced to provide guidance on achieving balanced biofilm dispersal

Minimum wage and export: evidence from Chinese firm-level data

This paper proposes a two-country trade equilibrium model with heterogeneous firms to investigate the influences of minimum wages and productivity on firms' exports. It shows that the influence of minimum wages on firms' exporting probability and foreign sales is negative while that of firms' productivity on their exports is positive. Econometric analysis based on the Annual Survey of Chinese Industrial Firms as well as the data of minimum wages collected ourselves from 1998 to 2007 verifies these predictions. Holding the other variables constant, if minimum wages and their productivity increase by 100%$, then the elasticity of minimum wage on firms' exporting sales is -8.6$ and increases by 1.6%$, respectively.Minimum wage, heterogeneous firm, productivity, export

Interface control of ferroelectricity in LaNiO3-BaTiO3 superlattices

LaNiO$_{3}$-BaTiO$_{3}$ superlattices with different types of interfaces are studied from first-principles density-functional theory. It is revealed that the ferroelectricity in the superlattice with (NiO$_2$)$^-$/(BaO)$^0$ interfaces is enhanced from that of the superlattice with (LaO)$^+$/(TiO$_2$)$^0$ interfaces. The origin lies at the polar discontinuity at the interface, which makes the holes localized within the (NiO$_2$)$^-$/(BaO)$^0$ interface, but drives a penetration of electrons into BaTiO$_3$ component near (LaO)$^+$/(TiO$_2$)$^0$ interface. Our calculations demonstrate an effective avenue to the robust ferroelectricity in BaTiO$_3$ ultrathin films.Comment: 14 pages, 6 figure

Spectrum-Efficient Triple-Layer Hybrid Optical OFDM for IM/DD-Based Optical Wireless Communications

In this paper, a triple-layer hybrid optical orthogonal frequency division multiplexing (THO-OFDM) for intensity modulation with direct detection (IM/DD) systems with a high spectral efficiency is proposed. We combine N-point asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM), N/2-point ACO-OFDM, and N/2-point pulse amplitude modulated discrete multitoned (PAM-DMT) in a single frame for simultaneous transmission. The time- and frequency-domain demodulation methods are introduced by fully exploiting the special structure of the proposed THO-OFDM. Theoretical analysis show that, the proposed THO-OFDM can reach the spectral efficiency limit of the conventional layered ACO-OFDM (LACO-OFDM). Simulation results demonstrate that, the time-domain receiver offers improved bit error rate (BER) performance compared with the frequency-domain with ∼40% reduced computation complexity when using 512 subcarriers. Furthermore, we show a 3 dB improvement in the peak-to-average power ratio (PAPR) compared with LACO-OFDM for the same three layers

Transcription activity hot spot, is it real or an artifact?

Transcription activity 'hot spots', defined as chromosome regions that contain more expression quantitative trait loci than would have been expected by chance, have been frequently detected both in humans and in model organisms. It has been common to consider the existence of hot spots as evidence for master regulation of gene expression. However, hot spots could also simply be due to highly correlated gene expressions or linkage disequilibrium and do not truly represent master regulators. A recent simulation study using real human gene expression data but simulated random single-nucleotide polymorphism genotypes showed patterns of clustering of expression quantitative trait loci that resemble those in actual studies [Perez-Enciso: Genetics 2004, 166: 547–554.]. In this study, to assess the credibility of transcription activity hot spots, we conducted genetic analyses on gene expressions provided by Genetic Analysis Workshop 15 Problem 1

Inverse Projection Representation and Category Contribution Rate for Robust Tumor Recognition

Sparse representation based classification (SRC) methods have achieved remarkable results. SRC, however, still suffer from requiring enough training samples, insufficient use of test samples and instability of representation. In this paper, a stable inverse projection representation based classification (IPRC) is presented to tackle these problems by effectively using test samples. An IPR is firstly proposed and its feasibility and stability are analyzed. A classification criterion named category contribution rate is constructed to match the IPR and complete classification. Moreover, a statistical measure is introduced to quantify the stability of representation-based classification methods. Based on the IPRC technique, a robust tumor recognition framework is presented by interpreting microarray gene expression data, where a two-stage hybrid gene selection method is introduced to select informative genes. Finally, the functional analysis of candidate's pathogenicity-related genes is given. Extensive experiments on six public tumor microarray gene expression datasets demonstrate the proposed technique is competitive with state-of-the-art methods.Comment: 14 pages, 19 figures, 10 table