Metallographic and corrosion research of copper from archaeological sites

In this study, copper slabs - ingots, from both Gdańsk and Krakow were examined. Besides metallographic examinations, attention was focused on analyses of corrosion products. The following techniques were applied: scanning electron microscopy with fluorescent X-ray microanalysis and X-ray diffraction. The conducted investigations enabled determination of the causes of corrosion in the old copper slabs, due mainly to the mediaeval alloying techniques and copper processing technologies

Cohesive and magnetic properties of grain boundaries in bcc Fe with Cr additions

Structural, cohesive, and magnetic properties of two symmetric $\Sigma3(111)$ and $\Sigma5(210)$ tilt grain boundaries (GBs) in pure bcc Fe and in dilute FeCr alloys are studied from first principles. Different concentration and position of Cr solute atoms are considered. We found that Cr atoms placed in the GB interstice enhance the cohesion by 0.5-1.2 J/m$^2$. Substitutional Cr in the layers adjacent to the boundary shows anisotropic effect on the GB cohesion: it is neutral when placed in the (111) oriented Fe grains, and enhances cohesion (by 0.5 J/m$^2$) when substituted in the boundary layer of the (210) grains. The strengthening effect of the Cr solute is dominated by the chemical component of the adhesive binding energy. Our calculations show that unlike the free iron surfaces, Cr impurities segregate to the boundaries of the Fe grains. The magnetic moments on GB atoms are substantially changed and their variation correlates with the corresponding relaxation pattern of the GB planes. The moments on Cr additions are 2-4 times enhanced in comparison with that in a Cr crystal and are antiparallel to the moments on the Fe atoms

AN ENZYMATIC FUNCTION ASSOCIATED WITH TRANSFORMATION OF FIBROBLASTS BY ONCOGENIC VIRUSES : I. CHICK EMBRYO FIBROBLAST CULTURES TRANSFORMED BY AVIAN RNA TUMOR VIRUSES

Chick embryo fibroblast cultures develop fibrinolytic activity after transformation by Rous sarcoma virus (RSV). This fibrinolytic activity is not present in normal cultures, and it does not appear after infection with either nontransforming strains of avian leukosis viruses or cytocidal RNA and DNA viruses. In cultures infected with a temperature sensitive mutant of RSV the onset of fibrinolysis appears after exposure to permissive temperatures and precedes by a short interval the appearance of morphological evidence of transformation. See PDF for Structure The rate of fibrinolysis in transformed cultures depends on the nature of the serum that is present in the growth medium: some sera (e.g., monkey or chicken serum) promote high enzymatic activity, while others (calf, fetal bovine) do not. Some sera contain inhibitors of the fibrinolysin. Based on the effect of a small number of known inhibitors, at least one step of the fibrinolytic process shows specificity resembling that of trypsin. The sera of sarcoma-bearing chickens contain an inhibitor of the fibrinolysin, whereas normal chicken sera do not. For general discussion, conclusions, and summary see the accompanying paper, part II, (J. Exp. Med. 137:112)

Accurate Representation of Microscopic Scatterers in Realistic Simulation of OCT Image Formation

There is currently much interest in developing OCT image formation models based on Maxwell's equations. However, all such models face a common challenge: how can microscopic scatterers be represented without limiting the overall size of the sample that can be modelled? Here we show how micro-scopic scatterers can be accurately represented on computational grids with cells too large to faithfully represent such scatterers using conventional approaches. We also validate this approach experimentally. This approach to OCT image simulation allows for image formation for biological tissues to be simulated with unprecedented realism

The Presampler for the Forward and Rear Calorimeter in the ZEUS Detector

The ZEUS detector at HERA has been supplemented with a presampler detector in front of the forward and rear calorimeters. It consists of a segmented scintillator array read out with wavelength-shifting fibers. We discuss its desi gn, construction and performance. Test beam data obtained with a prototype presampler and the ZEUS prototype calorimeter demonstrate the main function of this detector, i.e. the correction for the energy lost by an electron interacting in inactive material in front of the calorimeter.Comment: 20 pages including 16 figure

Computer Aided Identification of Small Molecules Disrupting uPAR/α5β1- Integrin Interaction: A New Paradigm for Metastasis Prevention

Disseminated dormant cancer cells can resume growth and eventually form overt metastases, but the underlying molecular mechanism responsible for this change remains obscure. We previously established that cell surface interaction between urokinase receptor (uPAR) and alpha5beta1-integrin initiates a sequel of events, involving MAPK-ERK activation that culminates in progressive cancer growth. We also identified the site on uPAR that binds alpha5beta1-integrin. Disruption of uPAR/integrin interaction blocks ERK activation and forces cancer cells into dormancy.Using a target structure guided computation docking we identified 68 compounds from a diversity library of 13,000 small molecules that were predicted to interact with a previously identified integrin-binding site on uPAR. Of these 68 chemical hits, ten inhibited ERK activation in a cellular assay and of those, 2 compounds, 2-(Pyridin-2-ylamino)-quinolin-8-ol and, 2,2'-(methylimino)di (8-quinolinol) inhibited ERK activation by disrupting the uPAR/integrins interaction. These two compounds, when applied in vivo, inhibited ERK activity and tumor growth and blocked metastases of a model head and neck carcinoma.We showed that interaction between two large proteins (uPAR and alpha5beta1-integrin) can be disrupted by a small molecule leading to profound downstream effects. Because this interaction occurs in cells with high uPAR expression, a property almost exclusive to cancer cells, we expect a new therapy based on these lead compounds to be cancer cell specific and minimally toxic. This treatment, rather than killing disseminated metastatic cells, should induce a protracted state of dormancy and prevent overt metastases

A rapid-response ultrasensitive biosensor for influenza virus detection using antibody modified boron-doped diamond

According to the World Health Organization (WHO), almost 2 billion people each year are infected worldwide with flu-like pathogens including influenza. This is a contagious disease caused by viruses belonging to the family Orthomyxoviridae. Employee absenteeism caused by flu infection costs hundreds of millions of dollars every year. To successfully treat influenza virus infections, detection of the virus during the initial development phase of the infection is critical, when tens to hundreds of virus-associated molecules are present in the patient’s pharynx. In this study, we describe a novel universal diamond biosensor, which enables the specific detection of the virus at ultralow concentrations, even before any clinical symptoms arise. A diamond electrode is surface-functionalized with polyclonal anti-M1 antibodies, which then serve to identify the universal biomarker for the influenza virus, M1 protein. The absorption of the M1 protein onto anti-M1 sites of the electrode change its electrochemical impedance spectra. We achieved a limit of detection of 1 fg/ml in saliva buffer for the M1 biomarker, which corresponds to 5–10 viruses per sample in 5 minutes. Furthermore, the universality of the assay was confirmed by analyzing different strains of influenza A virus