Distribution of Anopheles daciae and other Anopheles maculipennis complex species in Serbia.

Malaria is one of the most severe health problems facing the world today. Until the mid-twentieth century, Europe was an endemic area of malaria, with the Balkan countries being heavily infested. Sibling species belonging to the Anopheles maculipennis complex are well-known as effective vectors of Plasmodium in Europe.

Investigation of non-collinear spin states with scanning tunneling microscopy.

Most ferromagnetic and antiferromagnetic substances show a simple collinear arrangement of the local spins. Under certain circumstances, however, the spin configuration is non-collinear. Scanning tunneling microscopy with its potential atomic resolution is an ideal tool for investigating these complex spin structures.

Anthocyanin-rich extracts suppress the DNA-damaging effects of topoisomerase poisons in human colon cancer cells.

Scope: The effect of two anthocyanin-rich berry extracts (A, bilberry; B, red grape) on topoisomerases was investigated in a cell-free system and in human HT29 colon carcinoma cells. In parallel, their impact on DNA integrity was determined.

Methods And Results: The berry extracts suppressed the activity of topoisomerase I at concentrations ≥50 μg/mL.

Repair of DNA damage induced by the mycotoxin alternariol involves tyrosyl-DNA phosphodiesterase 1.

Alternariol (AOH) was reported recently to act as a topoisomerase poison. To underline the relevance of topoisomerase targeting for the genotoxic properties of AOH, we addressed the question whether human tyrosyl-DNA phosphodiesterase 1 (TDP1), an enzyme vital to the repair of covalent DNA-topoisomerase adducts, affects AOH-mediated genotoxicity. The relevance of TDP1 activity on AOH-induced genotoxicity was investigated by the comet assay in human cells overexpressing GFP chimera of TDP1 or the inactive mutant TDP1(H263A) as well as in cells subjected to siRNA-mediated knock-down of endogenous TDP1.

The formation of a metalloid Sn(10)[Si(SiMe(3))(3)](6) cluster compound and its relation to the alpha<-->beta tin phase transition.

Very recently it was shown that Sn monohalides can be prepared in preparative scale applying a preparative co-condensation technique. Here, a first reaction of Sn(i)Br is presented leading to the metalloid cluster compound Sn(10)[Si(SiMe(3))(3)](6) 1. This reaction can be seen as a first step to metalloid cluster compounds applying the disproportionation reaction of a metastable Sn monohalide.

[Si(SiMe3)3]6Ge18M (M = Zn, Cd, Hg): neutral metalloid cluster compounds of germanium as highly soluble building blocks for supramolecular chemistry.

Very recently it was shown that the metalloid cluster compound {Ge(9)[Si(SiMe(3))(3)](3)}(-) can be used for subsequent reactions as the shielding of the cluster core is rather incomplete. So the reaction of with M(+) sources of group 11 metals gives metalloid cluster compounds of the formulae {MGe(18)[Si(SiMe(3))(3)](6)}(-) (M = Au, Ag, Cu). These reactions can be seen as first steps into a supramolecular chemistry with metalloid cluster compounds.

Intermediate high index layer for laser mode tuning in organic semiconductor lasers.

We modified the optical properties of organic semiconductor distributed feedback lasers by introducing a high refractive index layer consisting of tantalum pentoxide between the substrate and the active material layer. A thin film of tris-(8-hydroxyquinoline) aluminium doped with the laser dye 4-dicyanomethylene-2-methyl-6-(p-dimethylamino-styryl)-4H-pyran was used as the active layer. By varying the intermediate layer thickness we could change the effective refractive index of the guided laser mode and thus the laser wavelength.

Few-photon transport in low-dimensional systems: interaction-induced radiation trapping.

We present a detailed analysis of the dynamics of photon transport in waveguiding systems in the presence of a two-level system. In these systems, quantum interference effects generate a strong effective optical nonlinearity on the few-photon level. We clarify the relevant physical mechanisms through an appropriate quantum many-body approach.

Purification and characterization of RecQ helicases of plants.

Helicases are essential for DNA metabolism. Different helicases have different properties tailored to fulfill their specific tasks. RecQ-helicases are known to be important in DNA repair and DNA recombination.

Anthropogenic versus geogenic contribution to total suspended atmospheric particulate matter and its variations during a two-year sampling period in Beijing, China.

Weekly samples of total suspended particles in air (TSP) were taken in south-east Beijing for a two-year period continuously from August 2005 to August 2007. Mass concentrations varied between 76 and 1028 microg m(-3) with an average concentration of 370 microg m(-3) for the whole period. The chemical composition and the mass concentration of aerosols in combination with meteorological data are reflecting specific influences of distinct aerosol sources on the pollution of Beijing's atmosphere.

Photocatalytic degradation of clofibric acid, carbamazepine and iomeprol using conglomerated TiO2 and activated carbon in aqueous suspension.

The combination of powdered activated carbon (PAC) and TiO(2) has been tested for synergistic/antagonistic effects in the photocatalytic degradation of carbamazepine, clofibric acid and iomeprol. Synergistic effects are thought to be caused by rapid adsorption on the PAC surface followed by diffusion to the TiO(2) surface and photocatalytic degradation. The Freundlich constant K(F) was used for comparing the sorption properties of the three substances and it was found that K(F) for clofibric acid was 3 times lower than for carbamazepine and iomeprol, regardless of the kind of PAC used.

Planning and simulation of microsurgical laser bone ablation.

Purpose: Laser ablation of hard tissue is not completely understood until now and not modeled for computer-assisted microsurgery. A precise planning and simulation is an essential step toward the usage of microsurgical laser bone ablation in the operating room.

Methods: Planning the volume for laser bone ablation is based on geometrical definitions.

Electrochemical machining of gold microstructures in LiCl/dimethyl sulfoxide.

LiCl/dimethyl sulfoxide (DMSO) electrolytes were applied for the electrochemical micromachining of Au. Upon the application of short potential pulses in the nanosecond range to a small carbon-fiber electrode, three-dimensional microstructures with high aspect ratios were fabricated. We achieved machining resolutions down to about 100 nm.

Computerized optimization of biventricular pacing using body surface potential map.

An improvement of biventricular pacing (BVP) could be possible by detecting the patient specific optimal pacemaker parameters. Body surface potential map (BSPM) is used to obtain the electrophysiology and pathology of an individual patient non-invasively. The clinical measurements of BSPM are used to parameterize the computer model of the heart to represent the individual pathology.

Nitrifying microorganisms in fixed-bed biofilm reactors fed with different nitrite and ammonia concentrations.

Nitrifying bacteria and archaea were fed in fixed-bed biofilm reactors with different nitrite and ammonia concentrations in synthetic and real wastewater. During high nitrite concentrations (rho(NO(2)(-))=5-10mg/L), an increase in the abundance of Nitrobacter species was detected with fluorescence in situ hybridization (FISH), while Nitrospira species disappeared to a large extent. During high ammonia concentrations (rho(NH(4)(+))=60-80 mg/L), a slight increase in ammonia-oxidizing bacteria was obtained, while the abundance of archaebacteria remained unchanged.

Opening up a dysprosium triangle by ligand oximation.

A simple trinuclear dysprosium complex shows complex slow relaxation of the magnetisation.

Ultra-Fast RAFT-HDA Click Conjugation: An Efficient Route to High Molecular Weight Block Copolymers.

The use of the reversible addition fragmentation chain transfer-hetero Diels-Alder (RAFT-HDA) click reaction for the modular construction of block copolymers is extended to the generation of high molecular weight materials. Cyclopentadienyl end-functionalized polystyrene (PS-Cp) prepared via both atom transfer radical polymerization (ATRP) and the RAFT process are conjugated to poly(isobornyl acrylate) (PiBoA) (also prepared via RAFT polymerization) to achieve well-defined block copolymers with molecular weights ranging from 34 000 to over 100 000 g · mol(-1) and with small polydispersities (PDI < 1.2).

Four-fold click reactions: Generation of tetrahedral methane- and adamantane-based building blocks for higher-order molecular assemblies.

A modular concept for the generation of achiral and chiral non-racemic tetrahedral tectons from common precursors was developed. The tectons presented here are based on tetraphenylmethane or 1,3,5,7-tetraphenyladamantane core structures. They are obtained through high-yielding four-fold click reactions, using either the tetraazido or the tetraalkyne precursors.

EELS of niobium and stoichiometric niobium-oxide phases--Part I: plasmon and near-edges fine structure.

A comprehensive electron energy-loss spectroscopy study of niobium (Nb) and stable Nb-oxide phases (NbO, NbO2, Nb2O5) was carried out. In this work (Part I), the plasmons and energy-loss near-edge structures (ELNES) of all relevant Nb edges (Nb-N2,3, Nb-M4,5, Nb-M2,3, Nb-M1, and Nb-L2,3) up to energy losses of about 2600 eV and the O-K edge are analyzed with respect to achieving characteristic fingerprints of Nb in different formal oxidation states (0 for metallic Nb, +2 for NbO, +4 for NbO2, and +5 for Nb2O5). Chemical shifts of the Nb-N2,3, Nb-M4,5, Nb-M2,3, and Nb-L2,3 edges are extracted from the spectra that amount to about 4 eV as the oxidation state increases from 0 for Nb to +5 for Nb2O5.

EELS of niobium and stoichiometric niobium-oxide phases--Part II: quantification.

A comprehensive electron energy-loss spectroscopy (EELS) study of niobium (Nb) and stable Nb-oxide phases (NbO, NbO2, Nb2O5) was carried out. Part II of this work is devoted to quantitative EELS by means of experimental k-factors derived from the intensity ratio of the O-K edge and the Nb-M4,5 or Nb-M2,3 edges for all three stable Nb-oxides. The precision and accuracy of the quantification are investigated with respect to the influence of intensity-measurement energy windows, background subtraction, and sample thickness.

Investigation of hydrogenation of toluene to methylcyclohexane in a trickle bed reactor by low-field nuclear magnetic resonance spectroscopy.

Low-field nuclear magnetic resonance (NMR) spectroscopy is applied to study the hydrogenation of toluene in a lab-scale reactor. A conventional benchtop NMR system was modified to achieve chemical shift resolution. After an off-line validity check of the approach, the reaction product is analyzed on-line during the process, applying chemometric data processing.

Use of fluorescence fingerprints for the estimation of bloom formation and toxin production of Microcystis aeruginosa.

The development of methods facilitating the detection of cyanobacterial blooms in drinking water reservoirs at an early stage is of great importance. Fluorescence spectroscopy could meet these requirements. The study contains the examination of possible correlations between the different maxima of a fluorescence excitation-emission matrix and the amount of produced and excreted toxins of a lab culture of Microcystis aeruginosa at different stages of growth.

On the quantitative click conjugation of molecular weight distributions: what can theoretically be expected?

The assessment of the success of a click conjugation for block copolymer formation often occurs via ill-defined criteria based on the qualitative shape of the size exclusion chromatography (SEC) distribution as well as unsuitable characteristics of these molecular weight distribution such as the peak molecular weight, M(p) . The data presented herein illustrate that from the shape of the SEC distribution, w(log M) versus log M, of the click product-under the assumption of a 100% efficient conjugation reaction-a conclusion about the effectiveness of the click conjugation cannot be derived. It is demonstrated that under certain conditions multi-modal molecular weight distributions are obtained from two well-defined monomodal initial distributions.

Nanoengineering and characterization of gold dipole nanoantennas with enhanced integrated scattering properties.

In this paper we present our approach for engineering gold dipole nanoantennas. Using electron-beam lithography we have been able to produce arrays of single gold antennas with dimensions from 70 to 300 nm total length with a highly reproducible nanoengineering protocol. Characterizing these gold nanoantenna architectures by optical means via dark-field microscopy and scattering spectroscopy gives the linear optical response function as a figure-of-merit for the antenna resonances, spectral linewidth and integrated scattering intensity.

Electrochemical behaviour of iron in a third-generation ionic liquid: cyclic voltammetry and micromachining investigations.

The electrochemical behaviour of Fe in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim](+)Ntf2(-)) and mixtures with Cl(-) is studied with the aim of investigating the applicability of ionic liquids (IL) for the electrochemical machining of iron. Whereas in pure IL iron could not be significantly dissolved, the addition of Cl(-) enables the active dissolution with anodic current densities up to several mA cm(-2). Although several anodic peaks appear in the cyclic voltammograms (CV), the distinct assignment of those electrochemical processes remain difficult.