A Transport Analysis of the BEEM Spectroscopy of Au/Si Schottky Barriers

A systematic transport study of the ballistic electron emission microscopy (BEEM) of Au/Si(100) and Au/Si(111) Schottky barriers for different thicknesses of the metal layer and different temperatures is presented. It is shown that the existing experimental data are compatible with a recently predicted bandstructure-induced non-forward electron propagation through the Au(111) layer.Comment: 5 pages, Latex-APS, 1 postscript figure, http://www.icmm.csic.es/Pandres/pedro.htm. Phys. Stat. Sol. (b) (to appear), HCIS-10 Conf, Berlin 199

Multiple evolutionary trajectories for non-O157 Shiga toxigenic Escherichia coli

AbstractBackgroundShiga toxigenic Escherichia coli (STEC) is an emerging global pathogen and remains a major cause of food-borne illness with more severe symptoms including hemorrhagic colitis and hemolytic-uremic syndrome. Since the characterization of the archetypal STEC serotype, E. coli O157:H7, more than 250 STEC serotypes have been defined. Many of these non-O157 STEC are associated with clinical cases of equal severity as O157. In this study, we utilize whole genome sequencing of 44 STEC strains from eight serogroups associated with human infection to establish their evolutionary relationships and contrast this with their virulence gene profiles and established typing methods.ResultsOur phylogenomic analysis delineated these STEC strains into seven distinct lineages, each with a characteristic repertoire of virulence factors. Some lineages included commensal or other E. coli pathotypes. Multiple independent acquisitions of the Locus for Enterocyte Effacement were identified, each associated with a distinct repertoire of effector genes. Lineages were inconsistent with O-antigen typing in several instances, consistent with lateral gene transfer within the O-antigen locus. STEC lineages could be defined by the conservation of clustered regularly interspaced short palindromic repeats (CRISPRs), however, no CRISPR profile could differentiate STEC from other E. coli strains. Six genomic regions (ranging from 500 bp - 10 kbp) were found to be conserved across all STEC in this dataset and may dictate interactions with Stx phage lysogeny.ConclusionsThe genomic analyses reported here present non-O157 STEC as a diverse group of pathogenic E. coli emerging from multiple lineages that independently acquired mobile genetic elements that promote pathogenesis.</jats:sec

Frustration-Induced Two Dimensional Quantum Disordered Phase in Piperazinium Hexachlorodicuprate

Piperazinium Hexachlorodicuprate (PHCC) is shown to be a frustrated quasi-two-dimensional quantum Heisenberg antiferromagnet with a gapped spectrum. Zero-field inelastic neutron scattering and susceptibility and specific heat measurements as a function of applied magnetic field are presented. At T = 1.5 K, the magnetic excitation spectrum is dominated by a single propagating mode with a gap, Delta = 1 meV, and bandwidth of approximately 1.8 meV in the (h0l) plane. The mode has no dispersion along the b* direction indicating that neighboring a-c planes of the triclinic structure are magnetically decoupled. The heat capacity shows a reduction of the gap as a function of applied magnetic field in agreement with a singlet-triplet excitation spectrum. A field-induced ordered phase is observed in heat capacity and magnetic susceptibility measurements for magnetic fields greater than H_c1 approximately equal to 7.5 Tesla. Analysis of the neutron scattering data reveals the important exchange interactions and indicates that some of these are highly frustrated.Comment: 13 pages with 14 figures, 7 pages of text, 6 pages of figures. Submitted to Phys. Rev. B 4/7/2001. email comments to [email protected] or [email protected]

The management of nanotechnology: analysis of technology linkages and the regional nanotechnology competencies

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordThis study maps the linkage of nanotechnologies and their clusters, identifies emerging and mature technologies and links to their application fields, and examines the profiles of the regional nanotechnology competencies. A model is proposed to assist with the analyses. The patent data were retrieved from the Thomson Innovation database, which were subsequently analysed with the Thomson Data Analyser. The results show technological linkages using the proposed linkage model, for example, the linkage between the cluster of nanotubes‐nanowires‐polymers and the cluster of nanowires‐semiconductors‐optical identifies a nanoelectronics domain. In the Techno‐Economic Network framework, the result shows that the United States maintains its position in the Science and Technology poles, revealing its strong competitiveness, while the nanotechnological competencies in Japan have lost strength significantly in recent years. Asian giants such as South Korea and China appear to be the most likely contenders for catching up with the United States. The theoretical contribution of this study is the theoretical framework that has been adapted and tested in this research. Practical contributions consist of descriptive and analytical findings based on actors' performances and the regions' competencies. The research offers a useful insight for academic and research practitioners on how an emerging field such as nanotechnology can be analysed, and a way forward for materialising science and technology policies in this field

An introduction to superhydrophobicity

This paper is derived from a training session prepared for COST P21. It is intended as an introduction to superhydrophobicity to scientists who may not work in this area of physics or to students. Superhydrophobicity is an effect where roughness and hydrophobicity combine to generate unusually hydrophobic surfaces, causing water to bounce and roll off as if it were mercury and is used by plants and animals to repel water, stay clean and sometimes even to breathe. The effect is also known as The Lotus Effect® and Ultrahydrophobicity. In this paper we introduce many of the theories used, some of the methods used to generate surfaces and then describe some of the implications of the effect

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

Differences in Longer-Term Smoking Abstinence After Treatment by Specialist or Nonspecialist Advisors: Secondary Analysis of Data From a Relapse Prevention Trial.

INTRODUCTION: Smokers receiving support in specialist centers tend to have a higher short-term quit rate, compared with those receiving support in other settings from professionals for whom smoking cessation is only a part of their work. We investigated the difference in longer-term abstinence after short-term smoking cessation treatment from specialist and nonspecialist smoking cessation services. METHODS: We conducted a secondary analysis of data from a randomized controlled trial of self-help booklets for the prevention of smoking relapse. The trial included 1088 short-term quitters from specialist stop smoking clinics and 316 from nonspecialist cessation services (such as general practice, pharmacies, and health trainer services). The difference in prolonged smoking abstinence from months 4 to 12 between specialist and nonspecialist services was compared. Multivariable logistic regression analyses were conducted to investigate the association between continuous smoking abstinence and the type of smoking cessation services, adjusted for possible confounding factors (including demographic, socioeconomic, and smoking history variables). RESULTS: The proportion of continuous abstinence from 4 to 12 months was higher in short-term quitters from specialist services compared with those from nonspecialist services (39% vs. 32%; P = .023). After adjusting for a range of participant characteristics and smoking variables, the specialist service was significantly associated with a higher rate of longer-term smoking abstinence (odds ratio: 1.48, 95% CI = 1.09% to 2.00%; P = .011). CONCLUSIONS: People who receive support to stop smoking from a specialist appear to be at lower risk of relapse than those receiving support from a nonspecialist advisor

Generation of Functional CLL-Specific Cord Blood CTL Using CD40-Ligated CLL APC

PMCID: PMC3526610This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Conformal oxide nanocoatings on electrodeposited 3D porous Ni films by atomic layer deposition

A versatile chemical synthesis procedure to obtain Al2O3 and Co2FeO4 nanolayers conformally coating a three-dimensional (3D) porous Ni film is presented. First, porous Ni is grown by hydrogen bubble template-assisted electrodeposition. Subsequently, Al2O3 and Co2FeO4 layers, with thickness ranging from 5 nm to 25 nm, are directly deposited onto the pore walls by atomic layer deposition, while maintaining the porous architecture and magnetic properties of the Ni scaffold. The crystal structure, thickness and distribution of elements within the composite coatings are investigated in detail. The resulting magnetic and wettability properties are assessed. Contact angle tests reveal that 3D porous Ni films become more hydrophilic after coating with Al2O3 or Co2FeO4. From a technological point of view, the obtained composite porous films could be appealing for applications like magnetically-actuated micro/nano-electromechanical systems (MEMS/NEMS) or bio-MEMS/NEMS, among others

Vaccination against GIP for the Treatment of Obesity

BACKGROUND: According to the WHO, more than 1 billion people worldwide are overweight and at risk of developing chronic illnesses, including cardiovascular disease, type 2 diabetes, hypertension and stroke. Current therapies show limited efficacy and are often associated with unpleasant side-effect profiles, hence there is a medical need for new therapeutic interventions in the field of obesity. Gastric inhibitory peptide (GIP, also known as glucose-dependent insulinotropic polypeptide) has recently been postulated to link over-nutrition with obesity. In fact GIP receptor-deficient mice (GIPR(-/-)) were shown to be completely protected from diet-induced obesity. Thus, disrupting GIP signaling represents a promising novel therapeutic strategy for the treatment of obesity. METHODOLOGY/PRINCIPAL FINDINGS: In order to block GIP signaling we chose an active vaccination approach using GIP peptides covalently attached to virus-like particles (VLP-GIP). Vaccination of mice with VLP-GIP induced high titers of specific antibodies and efficiently reduced body weight gain in animals fed a high fat diet. The reduction in body weight gain could be attributed to reduced accumulation of fat. Moreover, increased weight loss was observed in obese mice vaccinated with VLP-GIP. Importantly, despite the incretin action of GIP, VLP-GIP-treated mice did not show signs of glucose intolerance. CONCLUSIONS/SIGNIFICANCE: This study shows that vaccination against GIP was safe and effective. Thus active vaccination may represent a novel, long-lasting treatment for obesity. However further preclinical safety/toxicology studies will be required before the therapeutic concept can be addressed in humans