Zinc-phosphate nanoparticles with reversibly attached TNF-α analogs: an interesting concept for potential use in active immunotherapy

The authors’ intention was to prepare nanometer-sized zinc-phosphate nanoparticles that would be capable of binding histidine-rich TNF-α analogs onto their surface via a coordinative bond. Zinc-phosphate nanoparticles with a size of around 60 nm were prepared by a wet precipitation method and characterized using SEM, EDX, XRD, and DLS. First, BSA was bound as a testing protein, afterward two TNF-α analogs with decreased activity were bound to the described nanoparticles. The efficiency of binding and the existence of coordinative bond were confirmed with SDS-PAGE analysis. During binding, particle storage, and release experiments, the prepared TNF-α analogs retained their biological activity—hence the epitopes necessary for formation of antibodies stayed intact. The particle size did not change within a period of 2 weeks. No significant agglomeration was observed, the particles could be quickly dispersed in ultrasound. The present nanoparticles and the general approach of coordinative binding are widely applicable for natural and engineered histidine-rich proteins. The nanoparticles bearing appropriate TNF-α analogs could also be potentially used for active immunotherapy to tackle the chronic inflammatory diseases associated with pathogenically elevated levels of TNF-α.     

A hybrid method for multidimensional scaling using city-block distances

The problem of multidimensional scaling with city-block distances in the embedding space is reduced to a two level optimization problem consisting of a combinatorial problem at the upper level and a quadratic programming problem at the lower level. A hybrid method is proposed combining randomized search for the upper level problem with a standard quadratic programming algorithm for the lower level problem. Several algorithms for the combinatorial problem have been tested and an evolutionary global search algorithm has been proved most suitable. An experimental code of the proposed hybrid multidimensional scaling algorithm is developed and tested using several test problems of two- and three-dimensional scaling.     

Cyclodextrin modified gold nanoparticles-based open-tubular capillary electrochromatographic separations of polyaromatic hydrocarbons

In this study, spherical gold nanoparticles (GNPs) of 14.7 nm diameter, prepared by citrate reduction of a gold(III) salt and characterized by UV–Vis absorption spectrometry and transmission electron microscopy, were modified by a covalent attachment of 6^I-O-(3-mercaptopropyl)β-cyclodextrin (β-CD-SH) or per-6-deoxy-per-6-mercapto-β-cyclodextrin (β-CD-SH7). Subsequently, via three alternative approaches, β-CD-modified GNPs were immobilized onto the inner wall of the fused-silica (FS) capillaries and applied as special stationary phases for open-tubular capillary electrochromatography (OT-CEC). The first immobilization procedure was based on pre-derivatization of a FS capillary with (3-mercaptopropyl)trimethoxysilane (MPTMS) followed by subsequent reactions with GNPs and β-CD-SH or β-CD-SH7. The other two preparation protocols took advantage of sol–gel approach gaining a significant increase in the interaction surface for solutes. In both instances, the sol–gel created 3D structure was further covalently modified with GNPs. Serving that purpose, either β-CD-SH7 modified GNPs were used for the immobilization into the sol–gel matrix (“one-step sol–gel technique”) or native GNPs were immobilized first into the sol–gel matrix and subsequently modified with β-CD-SH7 (“two-step sol–gel technique”). The separation performance of CD-GNPs modified FS capillaries was tested by OT-CEC in reversed-phase mode applied to separation of a model mixture of five polyaromatic hydrocarbons. The highest separation efficiencies were obtained with the capillaries prepared by two-step sol–gel technique. However, with respect to the relatively low reproducibility of this method, the first of the above preparation procedures, i.e., a simple pre-derivatization of the FS capillary with MPTMS ensued with β-CD-SH7-GNPs immobilization seems to be more feasible approach providing decent separation efficiency.     

Major elements as possible factors of trace element urban pedochemical anomalies

The relationship between real total contents of the major elements Na, Mg, Al, Si, P, S, K, Ca, Ti, Fe and the trace elements Ag, As, B, Ba, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Se, Sn, V, U, Zn in topsoil from the central part of Vilnius is analysed. The amounts of most elements were determined by energy-dispersive X-ray fluorescence, while amounts of Ag, B, Co were measured by optical atomic emission spectrophotometry. Two factors were distinguished according to major elements: anthropogenic (A) including Ca, Mg, Fe, P, S and clayey (C) including K, Al, Ti. Boron, Mn, Cr and U are significantly correlated with members of both factors, Sb with none of them and other trace elements either with all (Cu, Zn, Pb, Se, Ba, Ni, Co) or with separate (V, Ag, Sn, Mo, As) members of the A-factor. Only B, Mn, Cr, U (partly their additive index Z1) are influenced by the C-factor, while twelve other trace elements (also their additive index Z2) are influenced by the A-factor. The additive index Z of all 17 elements is also affected by the A-factor. Four groups of sites have been distinguished according to normal or higher contents of both factors. The majority of trace element anomalies are related to the sites affected by the A-factor.     

Improved scheme for selection of potentially optimal hyper-rectangles in <Emphasis FontCategory="NonProportional">DIRECT</Emphasis>

We consider a box-constrained global optimization problem with a Lipschitz-continuous objective function and an unknown Lipschitz constant. The well known derivative-free global-search DIRECT (DIvide a hyper-RECTangle) algorithm performs well solving such problems. However, the efficiency of the DIRECT algorithm deteriorates on problems with many local optima and when the solution with high accuracy is required. To overcome these difficulties different regimes of global and local search are introduced or the algorithm is combined with local optimization. In this paper we investigate a different direction of improvement of the DIRECT algorithm and propose a new strategy for the selection of potentially optimal rectangles, what does not require any additional parameters or local search subroutines. An extensive experimental investigation reveals the effectiveness of the proposed enhancements.     

Editorial

The credit crisis is a complex societal problem in which many phenomena and actors are involved. If one wants to analyze the causes of this problem, try to stabilize the situation and prevent new fall backs, a multi-disciplinary approach is prescribed. A careful analysis based on the scientific methodology of societal complexity is needed in order to find how the credit crisis happened and how new crises can be prevented. Theories of multiple disciplines must be used by a multi disciplinary team to analyze the situation and to find sustainable options. This process can be accomplished by following the Compram Methodology of DeTombe. The Compram Methodology provides a framework for policy making which includes many methods and tools. The Compram Methodology is specialized to handle complex interdisciplinary world-wide problems and to offer a step-by-step approach of analyzing the problem, finding and implementing sustainable interventions and evaluating the effects. The Compram Methodology offers a bird’s-eye view on the complexity of the problem and gives directions to policy makers to build their decisions on using a multi-disciplinary, multi-actor approach. In this article the credit crisis is discussed in relation with the Compram Methodology. Aspects of the credit crisis are described with an emphasis on the role of the actors. Based on the Compram Methodology directions can be provided for handling the credit crisis and avoiding future similar problems.     

Approximation of circular arcs by parametric polynomial curves

In this paper the approximation of circular arcs by parametric polynomial curves is studied. If the angular length of the circular arc is h, a parametric polynomial curve of arbitrary degree \(n \in {\mathbb{N}}\) , which interpolates given arc at a particular point, can be constructed with radial distance bounded by h ²ⁿ . This is a generalization of the result obtained by Lyche and Mørken for odd n.