Real-Time Imaging of K atoms on Graphite: Interactions and Diffusion

Scanning tunneling microscopy (STM) at liquid helium temperature is used to image potassium adsorbed on graphite at low coverage (~0.02 monolayer). Single atoms appear as protrusions on STM topographs. A statistical analysis of the position of the atoms demonstrates repulsion between adsorbates, which is quantified by comparison with molecular dynamics simulations. This gives access to the dipole moment of a single adsorbate, found to be 10.5 Debye. Time lapse imaging shows that long range order is broken by thermally activated diffusion, with a 32 meV barrier to hopping between graphite lattice sites

Conductance fluctuations in quasi-two-dimensional systems: a practical view

The universal conductance fluctuations of quasi-two-dimensional systems are analyzed with experimental considerations in mind. The traditional statistical metrics of these fluctuations (such as variance) are shown to have large statistical errors in such systems. An alternative characteristic is identified, the inflection point of the correlation function in magnetic field, which is shown to be significantly more useful as an experimental metric and to give a more robust measure of phase coherence.Comment: 9 pages, 7 figure

Fabrication and functionalization of PCB gold electrodes suitable for DNA-based electrochemical sensing

The request of high specificity and selectivity sensors suitable for mass production is a constant demand in medical research. For applications in point-of-care diagnostics and therapy, there is a high demand for low cost and rapid sensing platforms. This paper describes the fabrication and functionalization of gold electrodes arrays for the detection of deoxyribonucleic acid (DNA) in printed circuit board (PCB) technology. The process can be implemented to produce efficiently a large number of biosensors. We report an electrolytic plating procedure to fabricate low-density gold microarrays on PCB suitable for electrochemical DNA detection in research fields such as cancer diagnostics or pharmacogenetics, where biosensors are usually targeted to detect a small number of genes. PCB technology allows producing high precision, fast and low cost microelectrodes. The surface of the microarray is functionalized with self-assembled monolayers of mercaptoundodecanoic acid or thiolated DNA. The PCB microarray is tested by cyclic voltammetry in presence of 5 mM of the redox probe K3Fe(CN6) in 0.1 M KCl. The voltammograms prove the correct immobilization of both the alkanethiol systems. The sensor is tested for detecting relevant markers for breast cancer. Results for 5 nM of the target TACSTD1 against the complementary TACSTD1 and non-complementary GRP, MYC, SCGB2A1, SCGB2A2, TOP2A probes show a remarkable detection limit of 0.05 nM and a high specificity

What Do Girls Learn from Dolls? Sexualized Stimuli and Girls’ Body Esteem and Academic Performance

Although a significant amount of research has investigated the effect of sexualization on women's body esteem and cognitive performance, few researchers have examined the effect of sexualization on girls. Additionally, research that has been conducted regarding girls' experiences of sexualization has primarily focused on media influences. The effect of dolls as a vector of sexualization for girls is understudied, and study of dolls in general has been largely focused around Barbie. The present study investigated the way in which different types of dolls influence girls' body esteem and academic performance and was designed to specifically determine the influence of sexualization. The study manipulated exposure to one of three dolls that were physically similar but represented different levels of sexualization: no sexualization (Corolle Camille), moderate sexualization (Barbie Fashionista), and high sexualization (Bratz Cloe). Twenty girls (ages 5-8) engaged in a 10-minute free play session with one of the three dolls and completed measures of appearance satisfaction, desire for thinness, body surveillance. Additionally, the girls completed age-appropriate math and verbal assessments. Contrary to our hypotheses, sexualization level of the doll did not influence body esteem or academic performance. These results do not support objectification theory (Fredrickson et al., 1998), as girls in our study were unaffected by exposure to sexualized stimuli. However, regardless of doll condition, girls performed better on the verbal task than the math task. These results could be indicative of a stereotype threat cue associated with doll play

Delivering the male: the effect of stereotype activation on trait inferences

The current study investigated the way in which gender of a character and the presence or absence of a male stereotype affect the perceived masculinity of said character. Forty undergraduates from Oregon State University completed a questionnaire rating the masculinity of one of four possible characters – one male without the stereotype present, one male with the stereotype present, one female without the stereotype present, and one female with the stereotype present. As hypothesized, it was found that the presence of a male stereotype significantly influenced the perceived masculinity of the character, as the masculinity ratings were higher for those characters with the stereotype present than those characters with no stereotype activation. There was no main effect for character gender, however, nor was there an interaction effect between stereotype activation and character gender. The results produced by this research can be used to develop studies to further investigate the effects of stereotype activation.Keywords: Stereotype, Trait inference

Spin dependent quantum interference in non-local graphene spin valves

Spin dependent electron transport measurements on graphene are of high importance to explore possible spintronic applications. Up to date all spin transport experiments on graphene were done in a semi-classical regime, disregarding quantum transport properties such as phase coherence and interference. Here we show that in a quantum coherent graphene nanostructure the non-local voltage is strongly modulated. Using non-local measurements, we separate the signal in spin dependent and spin independent contributions. We show that the spin dependent contribution is about two orders of magnitude larger than the spin independent one, when corrected for the finite polarization of the electrodes. The non-local spin signal is not only strongly modulated but also changes polarity as a function of the applied gate voltage. By locally tuning the carrier density in the constriction we show that the constriction plays a major role in this effect and indicates that it can act as a spin filter device. Our results show the potential of quantum coherent graphene nanostructures for the use in future spintronic devices

Itch and skin rash from chocolate during fluoxetine and sertraline treatment: Case report

BACKGROUND: The skin contains a system for producing serotonin as well as serotonin receptors. Serotonin can also cause pruritus when injected into the skin. SSRI-drugs increase serotonin concentrations and are known to have pruritus and other dermal side effects. CASE PRESENTATION: A 46-year-old man consulted his doctor due to symptoms of depression. He did not suffer from any allergy but drinking red wine caused vasomotor rhinitis. Antidepressive treatment with fluoxetine 20 mg daily was initiated which was successful. After three weeks of treatment an itching rash appeared. An adverse drug reaction (ADR) induced by fluoxetine was suspected and fluoxetine treatment was discontinued. The symptoms disappeared with clemastine and betametasone treatment. Since the depressive symptoms returned sertraline medication was initiated. After approximately two weeks of sertraline treatment he noted an intense itching sensation in his scalp after eating a piece of chocolate cake. The itch spread to the arms, abdomen and legs and the patient treated himself with clemastine and the itch disappeared. He now realised that he had eaten a chocolate cake before this episode and remembered that before the first episode he had had a chocolate mousse dessert. He had never had any reaction from eating chocolate before and therefore reported this observation to his doctor. CONCLUSIONS: This case report suggests that there may be individuals that are very sensitive to increases in serotonin concentrations. Dermal side reactions to SSRI-drugs in these patients may be due to high activity in the serotonergic system at the dermal and epidermo-dermal junctional area rather than a hypersensitivity to the drug molecule itself