Luminescent Cyclometalated Gold(III) Alkyl Complexes: Photophysical and Photochemical Properties

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Surface atomic arrangement visualization via reference-atom-specific holography

The reference-atom-specific holography was used to study the surface atomic arrangement visualization. By using the low-energy electron diffraction (LEED) intensity spectra, the direct reconstruction of 3D atomic images were demonstrated. A map of interatomic vectors was obtained by a multiple-incident angle and multiple-energy integral applied to spectra. The images of individual atoms in the vicinity of the selected reference atom were produced by a second integral transformation, using the chosen interatomic vector as a filter which was applied to the LEED spectra.published_or_final_versio

Probabilistic segmentation of volume data for visualization using SOM-PNN classifier

We present a new probabilistic classifier, called SOM-PNN classifier, for volume data classification and visualization. The new classifier produces probabilistic classification with Bayesian confidence measure which is highly desirable in volume rendering. Based on the SOM map trained with a large training data set, our SOM-PNN classifier performs the probabilistic classification using the PNN algorithm. This combined use of SOM and PNN overcomes the shortcomings of the parametric methods, the nonparametric methods, and the SOM method. The proposed SOM-PNN classifier has been used to segment the CT sloth data and the 20 human MRI brain volumes resulting in much more informative 3D rendering with more details and less artifacts than other methods. Numerical comparisons demonstrate that the SOM-PNN classifier is a fast, accurate and probabilistic classifier for volume rendering.published_or_final_versio

Direct observation of a Ga adlayer on a GaN(0001) surface by LEED Patterson inversion

A low-energy electron diffraction (LEED) Patterson function (PF) with multiple incident angles is used to obtain three-dimensional interatomic information of hexagonal GaN(0001) grown on a 6H-SiC(0001)-√3 x √3 surface. A Ga-Ga atomic pair between the Ga adlayer and the terminating Ga layer is observed in the LEED PF. This provides direct experimental evidence to support the structural model proposed by first-principles calculations. The LEED PF also shows that the GaN film has a hexagonal structure and the surface has single-bilayer steps.published_or_final_versio

The interplay between fluorescence and phosphorescence with luminescent gold(i) and gold(iii) complexes bearing heterocyclic arylacetylide ligands

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Highly phosphorescent platinum(II) emitters: photophysics, materials and biological applications

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Control of iron nitride formation by a high magnetic field

Author name used in this publication: J. LuVersion of RecordPublishe

High-throughput, quantitative analyses of genetic interactions in E. coli.

Large-scale genetic interaction studies provide the basis for defining gene function and pathway architecture. Recent advances in the ability to generate double mutants en masse in Saccharomyces cerevisiae have dramatically accelerated the acquisition of genetic interaction information and the biological inferences that follow. Here we describe a method based on F factor-driven conjugation, which allows for high-throughput generation of double mutants in Escherichia coli. This method, termed genetic interaction analysis technology for E. coli (GIANT-coli), permits us to systematically generate and array double-mutant cells on solid media in high-density arrays. We show that colony size provides a robust and quantitative output of cellular fitness and that GIANT-coli can recapitulate known synthetic interactions and identify previously unidentified negative (synthetic sickness or lethality) and positive (suppressive or epistatic) relationships. Finally, we describe a complementary strategy for genome-wide suppressor-mutant identification. Together, these methods permit rapid, large-scale genetic interaction studies in E. coli

Minim Typing – A Rapid and Low Cost MLST Based Typing Tool for Klebsiella pneumoniae

Here we report a single nucleotide polymorphism (SNP) based genotyping method for Klebsiella pneumoniae utilising high-resolution melting (HRM) analysis of fragments within the multilocus sequence typing (MLST) loci. The approach is termed mini-MLST or Minim typing and it has previously been applied to Streptococcus pyogenes, Staphylococcus aureus and Enterococcus faecium. Six SNPs were derived from concatenated MLST sequences on the basis of maximisation of the Simpsons Index of Diversity (D). DNA fragments incorporating these SNPs and predicted to be suitable for HRM analysis were designed. Using the assumption that HRM alleles are defined by G+C content, Minim typing using six fragments was predicted to provide a D = 0.979 against known STs. The method was tested against 202 K. pneumoniae using a blinded approach in which the MLST analyses were performed after the HRM analyses. The HRM-based alleles were indeed in accordance with G+C content, and the Minim typing identified known STs and flagged new STs. The tonB MLST locus was determined to be very diverse, and the two Minim fragments located herein contribute greatly to the resolving power. However these fragments are refractory to amplification in a minority of isolates. Therefore, we assessed the performance of two additional formats: one using only the four fragments located outside the tonB gene (D = 0.929), and the other using HRM data from these four fragments in conjunction with sequencing of the tonB MLST fragment (D = 0.995). The HRM assays were developed on the Rotorgene 6000, and the method was shown to also be robust on the LightCycler 480, allowing a 384-well high through-put format. The assay provides rapid, robust and low-cost typing with fully portable results that can directly be related to current MLST data. Minim typing in combination with molecular screening for antibiotic resistance markers can be a powerful surveillance tool kit

Rapid Assembly of Multiple-Exon cDNA Directly from Genomic DNA

Backgrouud. Polymerase chain reaction (PCR) is extensively applied in gene cloning. But due to the existence of introns, low copy number of particular genes and high complexity of the eukaryotic genome, it is usually impossible to amplify and clone a gene as a full-length sequence directly from the genome by ordinary PCR based techniques. Cloning of cDNA instead of genomic DNA involves multiple steps: harvest of tissues that express the gene of interest, RNA isolation, cDNA synthesis (reverse transcription), and PCR amplification. To simplify the cloning procedures and avoid the problems caused by ubiquitously distributed durable RNases, we have developed a novel strategy allowing the cloning of any cDNA or open reading frame (ORF) with wild type sequence in any spliced form from a single genomic DNA preparation. Methodology. Our Genomic DNA Splicing technique contains the following steps: first, all exons of the gene are amplified from a genomic DNA preparation, using software-optimized, highly efficient primers residing in flanking introns. Next, the tissue-specific exon sequences are assembled into one full-length sequence by overlapping PCR with deliberately designed primers located at the splicing sites. Finally, software-optimized outmost primers are exploited for efficient amplification of the assembled full-length products. Conclusions. The Genomic DNA Splicing protocol avoids RNA preparation and reverse transcription steps, and the entire assembly process can be finished within hours, Since genamic DNA is more stable than RNA, it may be a more practical cloning strategy for many genes, especially the ones that are very large and difficult to generate a full length cDNA using oligo-dT primed reverse transcription. With this technique, we successfully doned the full-length wild type coding sequence of human polymeric immunoglobulin receptor, which is 2295 bp in length and composed of 10 exons. © 2007 An et al.published_or_final_versio