An analytical study of central and in-network data processing for wireless sensor networks

This paper compares the performance of centralized and in-network data processing for wireless sensor networks (WSNs) under various deployment conditions on the real sensor hardware Sun SPOT from Sun Microsystems. We define several criteria to measure the quality of responses in WSN applications. Guided by an extensive experimental study, we discuss in detail the performance impacts of different deployment factors on algorithms that implement both centralized and in-network computing. Finally, performance guidelines are given to algorithm designers for WSN applications.     

Methylenreduktius?ure, ein neues Redukton aus Glucose

Zusammenfassung Zur hochdruckflülssigchromatographischen Untersuchung von Honig auf Restgehalte an Chloramphenicol (1) und Sulfathiazol (2) werden die Proben in 0,05 m-Phosphorsäure/Acetonitril gelöst und nach Ultrafiltration direkt injiziert. Die Trennungen werden über eine Phasen-Umkehr-Säule mit Alkyl Phenyl-Belegung durchgeführt. Als Laufmittelgemische dienen 0,05 m-Phosphorsäure/Acetonitril zur Analyse von1 und Wasser/Methanol (mit 0,005 m-PIC-BS [13]) für die Bestimmung von2. Die schnelle und einfache Aufarbeitungsmethode gewährleistet eine verlustfreie Wiederfindung bei einer Nachweisempfindlichkeit von 1 ppm.

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High pressure liquid chromatographic analysis of residues of drugs in honeyII. Chloramphenicol and sulfathiazole

Summary For the high pressure liquid chromatographic analysis of residues of chloramphenicol (1) and sulfathiazole (2) in honey, samples were dissolved in 0.05 m phosphoric acid/acetonitrile and after ultrafiltration injected immediately. The separations were carried out using a reversed phase column with alkylphenyl coated silica gel. For the analysis of1, 0.05 m phosphoric acid/acetonitrile was used as eluent and for the determination of2 water/methanol (with 0.005M PIC-BS [13]). The rapid and simple procedure allows for complete recovery and has a sensitivity of 1 ppm.

     

C60 fullerene enhances cisplatin anticancer activity and overcomes tumor cell drug resistance

We formulated and analyzed a novel nanoformulation of the anticancer drug cisplatin (Cis) with C60 fullerene (C60+Cis complex) and showed its higher toxicity toward tumor cell lines in vitro when compared to Cis alone.The highest toxicity of the complex was observed in HL-60/adr and HL-60/vinc chemotherapyresistant human leukemia cell sublines (resistant to Adriamycin and Vinculin,respectively).We discovered that the action of the C60+Cis complex is associated with overcoming the drug resistance of the tumor cell lines through observing an increased number of apoptotic cells in the Annexin V/PI assay.Moreover,in vivo assays with Lewis lung carcinoma (LLC) C57BL/6J male mice showed that the C60+Cis complex increases tumor growth inhibition,when compared to Cis or C60 fullerenes alone.Simultaneous1y,we conducted a molecular docking study and performed an Ames test.Molecular docking specifies the capability of a C60 fullerene to form van der Waals interactions with potential binding sites on P-glycoprotein (P-gp),multidrug resistance protein 1 (MRP-1),and multidrug resistance protein 2 (MRP-2) molecules.The observed phenomenon revealed a possible mechanism to bypass tumor cell drug resistance by the C,o+Cis complex.Additionally,the results of the Ames test show that the formation of such a complex diminishes the Cis mutagenic activity and may reduce the probability of secondary neoplasm formation.In conclusion,the C60+Cis complex effectively induced tumor cell death in vitro and inhibited tumor growth in vivo,overcoming drug resistance likely by the potential of the C60 fullerene to interact with P-gp,MRP-1,and MRP-2 molecules.Thus,the C60+Cis complex might be a potential novel chemotherapy modification.     

Glycosaminoglycan‐Based Biohybrid Hydrogels: A Sweet and Smart Choice for Multifunctional Biomaterials

Glycosaminoglycans (GAGs) govern important functional characteristics of the extracellular matrix (ECM) in living tissues. Incorporation of GAGs into biomaterials opens up new routes for the presentation of signaling molecules, providing control over development, homeostasis, inflammation, and tumor formation and progression. Recent approaches to GAG‐based materials are reviewed, highlighting the formation of modular, tunable biohybrid hydrogels by covalent and non‐covalent conjugation schemes, including both theory‐driven design concepts and advanced processing technologies. Examples of the application of the resulting materials in biomedical studies are provided. For perspective, solid‐phase and chemoenzymatic oligosaccharide synthesis methods for GAG‐derived motifs, rational and high‐throughput design strategies for GAG‐based materials, and the utilization of the factor‐scavenging characteristics of GAGs are highlighted.     

Magnetically inert medical projection system with an image‐guiding optical fiber

Abstract— A visual system for stimulating specific human brain functions inside a clinical magnetoencephalography (MEG) measurement chamber was developed. This system is based on a three‐panel LCOS projection unit and uses a 4.5‐m‐long image‐guiding optical‐fiber bundle to transfer the image into the magnetically shielded MEG measurement chamber. In addition to a proper optical system design, special attention had to be paid to all materials used inside the magnetically shielded chamber. Here, no interfering fields due to electrics or ferromagnetic materials are allowed. The system concept, optical design, and the realized prototype are presented.     

Speciation analysis of gadolinium-based MRI contrast agents in blood plasma by hydrophilic interaction chromatography/electrospray mass spectrometry

The first analytical method for simultaneous speciation analysis of five of the most important gadolinium-based magnetic resonance imaging (MRI) contrast agents in blood plasma samples was developed. Gd-DTPA (Magnevist), Gd-BT-DO3A (Gadovist), Gd-DOTA (Dotarem), Gd-DTPA-BMA (Omniscan), and Gd-BOPTA (Multihance) were separated by hydrophilic interaction liquid chromatography (HILIC) and detected with electrospray mass spectrometry (ESI-MS). Spiking experiments of blank plasma with Magnevist and Gadovist were performed to determine the analytical figures of merit and the recovery rates. The limits of detection ranged from 1 x 10 (-7) to 1 x 10 (-6) mol/L depending on the ionization properties of the individual compounds, and limits of quantification ranged from 5 x 10 (-7) to 5 x 10 (-6) mol/L. The linear concentration range comprised 2 orders of magnitude. With application of this method, blood plasma samples of 10 healthy volunteers, with Magnevist or Gadovist medication, were analyzed for Gd-DTPA and Gd-BT-DO3A, respectively. The obtained results were successfully validated with inductively coupled plasma-optical emission spectroscopy (ICP-OES).     

Development of a countergradient parking system for gradient liquid chromatography with online biochemical detection of serine protease inhibitors

A gradient HPLC approach in combination with a countergradient system for online biochemical detection (BCD) to screen for inhibitors of serine proteases is described. For gradient separations, this novel countergradient system was developed to produce a biocompatible constant solvent composition in the BCD. The countergradient system is based on retaining complete gradients in an additional preparative HPLC column, followed by subsequent and reversible elution to the separation column effluent. Major advantages compared with existing countergradient systems are that no additional LC pumps are needed and enhanced stability. The developed countergradient system was systematically characterized applying different gradient programs. Inhibitors eluting in a postcolumn continuous flow analysis interfere with the enzymatic release of fluorescent 7-amino-4-methylcoumarin (AMC) from an AMC-labeled peptide. The inhibitory activity of eluting substances is sensitively detected as the degree of reduced fluorescence intensity. This biochemical detection system (BCD) for proteases was validated with three known inhibitors of the benzamidine type. Their IC 50 values were in good accordance with the results of conventional plate reader assays. Finally, a small library of protease inhibitors was successfully screened with the combination of the BCD and the countergradient system.     

A one-pot, simple methodology for cassette randomisation and recombination for focused directed evolution

Protein engineering is currently performed either by rational design, focusing in most cases on only a few positions modified by site-directed mutagenesis, or by directed molecular evolution, in which the entire protein-encoding gene is subjected to random mutagenesis followed by screening or selection of desired phenotypes. A novel alternative is focused directed evolution, in which only fragments of a protein are randomised while the overall scaffold of a protein remains unchanged. For this purpose, we developed a PCR technique using long, spiked oligonucleotides, which allow randomising of one or several cassettes in any given position of a gene. This method allows over 95% incorporation of mutations independently of their position within the gene, yielding sufficient product to generate large libraries, and the possibility of simultaneously randomising more than one locus at a time, thus originating recombination. The high efficiency of this method was verified by creating focused mutant libraries of Pseudomonas fluorescens esterase I (PFEI), screening for altered substrate selectivity and validating against libraries created by error-prone PCR. This led to the identification of two mutants within the OSCARR library with a 10-fold higher catalytic efficiency towards p-nitrophenyl dodecanoate. These PFEI variants were also modelled in order to explain the observed effects.     

Photoactivation of CdSe/ZnS quantum dots embedded in silica colloids

A study of the influence of the local environment on the light-induced luminescence enhancement of CdSe/ZnS quantum dots (QD) embedded in silica colloids that are dispersed in various solvents is presented. The photoluminescence of the embedded QD is enhanced up to a factor of ten upon photoactivation by ultraviolet or visible light. This enhancement is strongly dependent on the local environment. The thickness-dependent permeability of the silica shell covering the QD controls the influence of the solvent on the QD. If foreign ions are present the activation state is stabilized after termination of the activation, whereas in their absence the process is partially reversible. A new qualitative model for the photoactivation of QD in various environments is developed. It comprises light-induced passivation and subsequent oxidation processes. The embedded QD also retain their fluorescence quantum yield inside living cells. Moreover, they can be activated for many hours in living cells by laser radiation in the visible regime.