Antimicrobial Properties and Cytotoxic Effect of Imidazolium Geminis with Tunable Hydrophobicity

Antimicrobial, membranotropic and cytotoxic properties of dicationic imidazolium surfactants of n-s-n (Im) series with variable length of alkyl group (n = 8, 10, 12, 14, 16) and spacer fragment (s = 2, 3, 4) were explored and compared with monocationic analogues. Their activity against a representative range of Gram-positive and Gram-negative bacteria, and also fungi, is characterized. The relationship between the biological activity and the structural features of these compounds is revealed, with the hydrophobicity emphasized as a key factor. Among dicationic surfactants, decyl derivatives showed highest antimicrobial effect, while for monocationic analogues, the maximum activity is observed in the case of tetradecyl tail. The leading compounds are 2–4 times higher in activity compared to reference antibiotics and prove effective against resistant strains. It has been shown that the antimicrobial effect is not associated with the destruction of the cell membrane, but is due to specific interactions of surfactants and cell components. Importantly, they show strong selectivity for microorganism cells while being of low harm to healthy human cells, with a SI ranging from 30 to 100.     

Extending the Capabilities of Single Particle Mass Spectrometry: II. Measurements of Aerosol Particle Density without DMA

Particle density is an important and useful property that is difficult to measure because it usually requires two separate instruments to measure two particle attributes. As density measurements are often performed on size-classified particles, they are hampered by low particle numbers, and hence poor temporal resolution. We present here a new method for measuring particle densities using our single particle mass spectrometer, SPLAT. This method takes advantage of the fact that the detection efficiency in our single particle mass spectrometer drops off very rapidly as the particle size decreases below 100 nm creating a distinct sharp feature on the small particle side of the vacuum aerodynamic size distribution. Thus, the two quantities needed to determine particle density, the particle diameter and vacuum aerodynamic diameter, are known. We first test this method on particles of known compositions and densities to find that the densities it yields are accurate. We then apply the method to obtain the densities of particles that were characterized during instrument field deployments. We illustrate how the method can also be used to measure the density of chemically resolved particles. In addition, we present a new method to characterize the instrument detection efficiency as a function of particle size that relies on measuring the mobility and vacuum aerodynamic size distributions of polydisperse spherical particles of known density. We show that a new aerodynamic lens used in SPLAT II improves instrument performance, making it possible to detect 83 nm particles with 50% efficiency.     

Utilization of lignocellulosic fibers in molded polyester composites

Using rice straw, bagasse, and cotton stalk fibers as reinforcing fillers in polyester composite was studied. The effects of fiber loading and fiber size on the modulus of rupture (MOR), modulus of elasticity (MOE), tensile strength, water absorption, and thickness swelling were investigated as well. The effect of esterification using maleic anhydride on the aforementioned properties also was studied. Ultraviolet light resistance and thermal behavior of the produced composites were also investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 653–660, 2003     

Study of the formation processes of gold droplet arrays on Si substrates by high temperature anneals

In this study, the peculiarities of the transformations of gold films deposited on the Si wafer surfaces as a result of high temperature anneals are investigated experimentally depending on the conditions of wafer surface preparation and the annealing regimes. The morphology and the distribution functions of the crystallites of gold films as well as the gold droplets formed as a result of anneals are studied as functions of annealing temperature, type of annealing (rapid thermal or rapid furnace annealing), and the state of the surface of Si wafers. The results obtained can be used for the controlled preparation of the arrays of catalytic gold droplets for subsequent growth of Si wire-like crystals.     

Comparison of release behaviour from microcapsules and microspheres

The plasticizing effect of core oil in the polymer shell of core–shell particles, so-called microcapsules, was here examined. The study involved release measurements of 4-nitroanisole into aqueous solution from two types of microparticles. In the first study, a microcapsule with PMMA shell and hexadecane core was examined. The second type of particle was a homogeneous PMMA microsphere containing no oil. Experimental data were compared to models that describe release by a diffusion mechanism out from core–shell particles as well as homogeneous spherical particles. Results clearly show that the alkane oil has a plasticizing effect on the PMMA shell, thereby generating a faster release of 4-nitroanisole. In both types of microparticles, the diffusion coefficients of 4-nitroanisole could be determined. The findings increase our understanding of important parameters in the microcapsule design with regard to tuning the release behaviour. Using microparticles, the ambition is to prolong the protection of paint and other coatings against fouling.     

A Series of 2-((1-Phenyl-1H-imidazol-5-yl)methyl)-1H-indoles as Indoleamine 2,3-Dioxygenase 1 (IDO1) Inhibitors

Indoleamine 2,3-dioxygenase 1 (IDO1) is a promising therapeutic target in cancer immunotherapy and neurological disease. Thus, searching for highly active inhibitors for use in human cancers is now a focus of widespread research and development efforts. In this study, we report the structure-based design of 2-(5-imidazolyl)indole derivatives, a series of novel IDO1 inhibitors which have been designed and synthesized based on our previous study using N1-substituted 5-indoleimidazoles. Among these, we have identified one with a strong IDO1 inhibitory activity (IC₅₀=0.16 μM, EC₅₀=0.3 μM). Structural-activity relationship (SAR) and computational docking simulations suggest that a hydroxyl group favorably interacts with a proximal Ser167 residue in Pocket A, improving IDO1 inhibitory potency. The brain penetrance of potent compounds was estimated by calculation of the Blood Brain Barrier (BBB) Score and Brain Exposure Efficiency (BEE) Score. Many compounds had favorable scores and the two most promising compounds were advanced to a pharmacokinetic study which demonstrated that both compounds were brain penetrant. We have thus discovered a flexible scaffold for brain penetrant IDO1 inhibitors, exemplified by several potent, brain penetrant, agents. With this promising scaffold, we provide herein a basis for further development of brain penetrant IDO1 inhibitors.     

Characterization of Ni-Coated WS2 Nanotubes for Hydrodesulfurization Catalysis

A reactivity screening of new nano-hydrodesulfurization (HDS) catalysts was conducted using an ambient pressure flow reactor as well as ultra-high vacuum kinetics techniques. Thiophene was used as a probe molecule. Clean multiwall WS₂ nanotubes (INT-WS₂) as well as Ni- and Co-coated INT-WS₂ were considered. In addition, undoped MoS₂ and Re-doped nanoparticles with fullerene-like structures were studied. Commercial Ni and Co HDS catalysts from Haldor Topsoe (Denmark) as well as “nano MoS₂” from Impex Corp. (USA) were considered as reference materials. The lab-synthesized and commercial systems broke down thiophene into quite similar non-sulfur containing products, as identified by a gas chromatograph. The Ni and Co promoted catalysts showed similar thiophene conversion rates. Although the commercial catalysts had larger thiophene conversion rates than the laboratory-synthesized systems, the Re-doped nano-HDS catalyst showed quite low rates of formation of H₂S, an undesirable by-product.     

Measurement of functional inability and quality of life in cardiac failure. Transcultural adaptation and validation of the Goldman, Minnesota and Duke questionnaires

Cardiac failure has a big impact on the daily life of patients and this can be evaluated using quality of life questionnaires. The aim of this study was to translate and adapt for the French population and test the validity of two quality of life self-administered-questionnaires: the Duke health Profile, the Minnesota Quality of Life Questionnaire in Cardiac Failure and one function capacity questionnaire, the Goldman Specific Activity Scale. The questionnaires were translated and retranslated then submitted to a committee of experts: the final version was presented to 30 patients. The study of the quantitative properties of the three instruments was performed on a sample of 74 patients with cardiac failure to assess their validity and 26 stable patients after cardiac transplantation to test reproducibility. The results of this study show that these three instruments are valid and reproducible and are comparable to the original documents: Cronbach's Alpha ranging from 0.54 to 0.78 for the Duke, except for the social dimension, and from 0.73 to 0.93 for the Minnesota, except for its incapacity dimension, intraclass correlation coefficient > 0.6 in all dimensions. The validity of convergence with LVEF and the NYHA measured during hospitalisation for decompensation was poor, except for the Goldman. The three instruments provided coherent information. The authors conclude that a structured method allows transcultural adaptation of instruments of evaluation of quality of life, the French version having comparable properties to the original documents: they may be used for clinical research.     

Computing in Totally Anonymous Asynchronous Shared Memory Systems

In the totally anonymous shared memory model of asynchronous distributed computing, processes have no identifiers and run identical programs. Moreover, processes have identical interface to the shared memory, and in particular, there are no single-writer registers. This paper assumes that processes do not fail, and the shared memory consists only of read/write registers, which are initialized to some default value. A complete characterization of the functions and agreement tasks that can be solved in this model is presented. Furthermore, it is shown that if a function is computable, then two registers are sufficient for some algorithm to compute it. Consensus is an important agreement task that can be computed. The paper proves logarithmic lower bounds on the number of registers and rounds needed for solving consensus in this model. A consensus protocol using a linear number of shared registers and rounds is also presented.     

Konzeption einer Kollaborationsplattform für die zwischenbetriebliche Softwareerstellung

The development of business application software is increasingly based on the development of different components by various suppliers. In the next step, system vendors integrate these components. Hereby, inter-organizational collaboration becomes more and more important for the software industry. In order to strengthen the value-added processes within these established software supply chains, the Ministry of Economic Affairs in Baden-Württemberg funded the project TASK that aims at fostering inter-organizational design, integration, and implementation of software components. The present article on the one hand provides an insight into the structure as well as the progress of this project and, on the other hand, presents academic research results in terms of an empirical analysis of barriers and drivers of interorganizational collaboration and of the purposeful design of a collaboration platform. The article concludes with a summary and a discussion of current and upcoming issues in establishing and sustaining inter-organizational collaboration structures within the software industry.