Electrophoretic deposition of bacterial cells

The possibility to use alternating current electrophoretic deposition (AC-EPD) to deposit living cells in the form of Staphylococcus aureus and Escherichia coli on stainless steel was assessed. The experimental results revealed that these bacteria can be successfully deposited on metallic surfaces from demineralized water and sucrose based solutions using asymmetric unbalanced electric fields. Cell viability of the deposited bacteria was influenced by the strain and deposition medium.     

Bis coumarinyl bis triazolothiadiazinyl ethane derivatives: Synthesis,antiviral activity evaluation,and molecular docking studies

A series of novel 3,3′-(3,3′-(dihydroxy/hydroxyethane-1,2-diyl)bis(7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine-6,3-diyl))bis(2H-chromen-2-ones) were prepared by the condensation of thiocarbohydrazide with tartaric acid or malic acid followed by various 3-(2-bromoacetyl)-2H-chromen-2-ones in two steps with good yields. All the synthesized compounds were characterized by analytical and spectral (IR, ¹H NMR, ¹³C NMR, and mass) data. These synthesized bis(triazolothiadiazinyl coumarin) compounds were evaluated for broad spectrum of antiviral activity. Among all the tested compounds, compound 5f exhibited antiviral activity against H1N1 virus. The molecular docking studies of these compounds against H1N1 neuraminidase enzyme were performed. The binding affinity and binding values were compared with standard drugs.     

Superconductivity on the border of weak itinerant ferromagnetism in UCoGe

We report the coexistence of ferromagnetic order and superconductivity in UCoGe at ambient pressure. Magnetization measurements show that UCoGe is a weak ferromagnet with a Curie temperature T(C)=3 K and a small ordered moment m(0)=0.03 micro(B). Superconductivity is observed with a resistive transition temperature T(s)=0.8 K for the best sample. Thermal-expansion and specific-heat measurements provide solid evidence for bulk magnetism and superconductivity. The proximity to a ferromagnetic instability, the defect sensitivity of T(s), and the absence of Pauli limiting, suggest triplet superconductivity mediated by critical ferromagnetic fluctuations.     

On deflection fields, weak-focusing and strong-focusing storage rings for polar molecules

In this paper, we analyze electric deflection fields for polar molecules in terms of a multipole expansion and derive a simple but rather insightful expression for the force on the molecules. Ideally, a deflection field exerts a strong, constant force in one direction, while the force in the other directions is zero. We show how, by a proper choice of the expansion coefficients, this ideal can be best approximated. We present a design for a practical electrode geometry based on this analysis. By bending such a deflection field into a circle, a simple storage ring can be created; the direct analog of a weak-focusing cyclotron for charged particles. We show that for realistic parameters a weak-focusing ring is only stable for molecules with a very low velocity. A strong-focusing (alternating-gradient) storage ring can be created by arranging many straight deflection fields in a circle and by alternating the sign of the hexapole term between adjacent deflection fields. The acceptance of this ring is numerically calculated for realistic parameters. Such a storage ring might prove useful in experiments looking for an EDM of elementary particles.     

The Cellular Interactions of PEGylated Gold Nanoparticles: Effect of PEGylation on Cellular Uptake and Cytotoxicity

Poly(ethylene glycol) (PEG) is frequently used to coat various medical nanoparticles (NPs). As PEG is known to minimize NP interactions with biological specimens, the question remains whether PEGylated NPs are intrinsically less toxic or whether this is caused by reduced NP uptake. In the present work, the effect of gold NP PEGylation on uptake by three cell types is compared and evaluated the effect on cell viability, oxidative stress, cell morphology, and functionality using a multiparametric methodology. The data reveal that PEGylation affects cellular NP uptake in a cell‐type‐dependent manner and influences toxicity by different mechanisms. At similar intracellular NP numbers, PEGylated NPs are found to yield higher levels of cell death, mostly by induction of oxidative stress. These findings reveal that PEGylation significantly reduces NP uptake, but that at similar functional (= cell‐associated) NP levels, non‐PEGylated NPs are better tolerated by the cells.     

A computer model to predict traffic noise in urban situations under free flow and traffic light conditions

A computer model is presented for predicting traffic noise indices in built-up situations for free flow traffic conditions and for a flow interrupted by a traffic light. The stream of vehicles is simulated by a given time headway distribution, and a transfer function obtained from a 1 : 100 scale model is used to simulate the specific built-up situation. Different time headway distributions result in only very small discrepancies; even the simple “equally spaced” distribution is adequate for predicting noise indices with high accuracy, unless L₉₀ has to be predicted. In eight built-up situations along a road with freely flowing traffic only minor mutual differences are found when L₁ ? L_eq and L₁₀ ? L_eq are compared, but L₅₀ and L₉₀, and consequently TNI and L_np, show discrepancies of the order of 10 dB(A). If a traffic light is introduced the value of L_eq rises compared with the free flow case, and the values of L₁ and L₁₀ increase, especially at higher traffic intensities, while L₅₀ and L₉₀ decrease. If the noise indices are calculated as a function of the distance along the road to the traffic light increases in L₁, L₁₀ and L_eq are found at about 50 m beyond the traffic light. The principal cause for this increase appears to be the differences between the peak levels of an accelerating car and the sound level at the ultimate speed. More in situ measurements are required to test the accuracy of the model, especially for accelerating vehicles.     

Critical phenomena for a triangular spin lattice I: Triplet interactions

Critical phenomena in an Ising-like spin system on a triangular lattice are studied by means of the renormalization theory. The critical indices of the critical point due to triplet interactions are determined approximately, in fair agreement with the exponents, known from the exact solution due to Baxter and Wu. The cross-over from triplet critical behavior to ferromagnetic (nearest neighbor) critical behavior is calculated.     

Development of a method for assessing the relative contribution of waterborne and dietary exposure to zinc bioaccumulation in <Emphasis Type="Italic">Daphnia magna</Emphasis> by using isotopically enriched tracers and ICP–MS detection

In order to study the effect of anthropogenic substances on freshwater and marine ecosystems and to develop methods to derive water-quality criteria, ecotoxicological testing is required. While toxicity assessments are traditionally based on dissolved metal concentrations, assuming that toxicity is caused by waterborne metal only, it was recently pointed out that also the dietary exposure route should be carefully considered and interpreted in regulatory assessments of zinc. In this context, the aim of this experimental study was to develop a method which allows the uptake of waterborne and dietary zinc by Daphnia magna and the interaction between both exposure routes to be studied. Therefore, the setup of a dual isotopic tracer study was required. During several days, daphnids were exposed to ⁶⁷Zn and ⁶⁸Zn via the dietary and the waterborne routes, respectively, and after several time intervals the daphnids were sampled and subjected to isotopic analysis by means of inductively coupled plasma mass spectrometry (ICP–MS). In order to obtain reliable and accurate results for zinc, special care was taken to prevent contamination and to deal with the spectral interferences traditionally hindering the determination of zinc. The figures of merit of both a quadrupole-based ICP–MS instrument equipped with a dynamic reaction cell, and a sector field ICP–MS unit were studied, and it was concluded that by using a sector field mass spectrometer operated at medium mass resolution all interferences could be overcome adequately. Although the set-up of the exposure experiments seems to be rather simple at first sight, it was shown in this work that several (dynamic) variables can have an influence on the results obtained and on the subsequent data interpretation. The importance of these confounding factors was examined, and on the basis of preliminary calculations it became clear that not only the isotopic composition of the daphnids has to be studied—adequate monitoring of the isotopic composition of the dissolved phase and the algae during the exposure of the daphnids is also required to accurately discriminate between uptake from water and from food. Lieve I.L. Balcaen and Karel A.C. De Schamphelaere contributed equally to this study