bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of Eimeria tenella CDK‐Related Kinase 2: From Target Identification to Lead Compounds
Authors: Engels Kristin , Beyer Carsten , Suárez Fernández Maria L. , Bender Frank , Gaßel Michael , Unden Gottfried , Marhöfer Richard J. , Mottram Jeremy C. , Selzer Paul M. 
Published: June 2010

AbstractApicomplexan parasites encompass several human‐ and animal‐pathogenic protozoans such as Plasmodium falciparum, Toxoplasma gondii, and Eimeria tenella. E. tenella causes coccidiosis, a disease that afflicts chickens, leading to tremendous economic losses to the global poultry industry. The considerable increase in drug resistance makes it necessary to develop new therapeutic strategies against this parasite. Cyclin‐dependent kinases (CDKs) are key molecules in cell‐cycle regulation and are therefore prominent target proteins in parasitic diseases. Bioinformatics analysis revealed four potential CDK‐like proteins, of which one—E. tenella CDK‐related kinase 2 (EtCRK2)—has already been characterized by gene cloning and expression.1 By using the CDK‐specific inhibitor flavopiridol in EtCRK2 enzyme assays and schizont maturation assays (SMA), we could chemically validate CDK‐like proteins as potential drug targets. An X‐ray crystal structure of human CDK2 (HsCDK2) served as a template to build protein models of EtCRK2 by comparative homology modeling. Structural differences in the ATP binding site between EtCRK2 and HsCDK2, as well as chicken CDK3, were addressed for the optimization of selective ATP‐competitive inhibitors. Virtual screening and “wet‐bench” high‐throughput screening campaigns on large compound libraries resulted in an initial set of hit compounds. These compounds were further analyzed and characterized, leading to a set of four promising lead compounds for development as EtCRK2 inhibitors.
Near‐lossless compression methods for spectral images
Authors: Ciprian R. , Carbucicchio M. 
Published: June 2010

AbstractIn this work, several near‐lossless compression methods for spectral images have been analyzed and compared. These methods are based both on the principal component analysis (PCA) and on the choice of a minimum number of spectral points, selected following different criteria. The analysis, initially carried out on 14 National Physical Laboratory tiles of certified colour, has been extended to some spectral images of paintings taken at the National Gallery of Parma (Italy). The comparison of the results with those obtained by applying the PCA analysis shows that the best method indicated as “method of a few significant points” allows reducing the spectral image size of a factor of 10 without loss of spectral and colour information. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010
Characterizing Single‐Molecule FRET Dynamics with Probability Distribution Analysis
Authors: Santoso Yusdi , Torella Joseph P. , Kapanidis Achillefs N. 
Published: June 2010

AbstractProbability distribution analysis (PDA) is a recently developed statistical tool for predicting the shapes of single‐molecule fluorescence resonance energy transfer (smFRET) histograms, which allows the identification of single or multiple static molecular species within a single histogram. We used a generalized PDA method to predict the shapes of FRET histograms for molecules interconverting dynamically between multiple states. This method is tested on a series of model systems, including both static DNA fragments and dynamic DNA hairpins. By fitting the shape of this expected distribution to experimental data, the timescale of hairpin conformational fluctuations can be recovered, in good agreement with earlier published results obtained using different techniques. This method is also applied to studying the conformational fluctuations in the unliganded Klenow fragment (KF) of Escherichia coli DNA polymerase I, which allows both confirmation of the consistency of a simple, two‐state kinetic model with the observed smFRET distribution of unliganded KF and extraction of a millisecond fluctuation timescale, in good agreement with rates reported elsewhere. We expect this method to be useful in extracting rates from processes exhibiting dynamic FRET, and in hypothesis‐testing models of conformational dynamics against experimental data.
Chemistry of O‐ and H‐Containing Species on the (001) Surface of Anatase TiO2: A DFT Study
Authors: Hussain Akhtar , Gracia Jose , Nieuwenhuys Ben E. , Niemantsverdriet J. W. (Hans) 
Published: June 2010

AbstractThe chemistry of oxygen, hydrogen, water, and other species containing both oxygen and hydrogen atoms on the anatase TiO2 (001) surface is investigated by DFT. The adsorption energy of atoms and radicals depends appreciably on the position and mode of adsorption, and on the coverage. Molecular hydrogen and oxygen interact weakly with the clean surface. However, H2O dissociates spontaneously to give two nonidentical hydroxyl groups, and this provides a model for hydroxylation of TiO2 surfaces by water. The mobility of the hydroxyl groups created by water splitting is initially impeded by a diffusion barrier close to 1 eV. The O2 adsorption energy increases significantly in the presence of H atoms. Hydroperoxy (OOH) formation is feasible if at least two H atoms are present in the direct vicinity of O2. In the adsorbed OOH, the OO bond is considerably lengthened and thus weakened.
Stability of Gold and Platinum Nanowires on Graphite Edges
Authors: Soldano Germán José , Quaino Paola , Santos Elizabeth , Schmickler Wolfgang 
Published: June 2010

AbstractThe stability of coinage and noble metal nanowires supported on graphite steps is examined by density functional theory. In particular, we study the stability of supported gold and platinum wires and compare their chemical properties with those of surfaces and bare wires. A substantially stronger bond with graphite was found for platinum wires due to unfilled antibonding states, which are occupied in the case of gold. This difference has direct consequences for the adsorption of hydrogen. This reaction can occur either on the wire or directly on graphite steps. In the case of gold, the reaction is favoured on steps, while on platinum wires, it has no thermodynamical preferences. Our results suggest that, in early stages of wire formation, hydrogen could desorb gold from graphite, but not platinum.
Carbon Dioxide Capture on Amine‐Rich Carbonaceous Materials Derived from Glucose
Authors: Zhao Li , Bacsik Zoltan , Hedin Niklas , Wei Wei , Sun Yuhan , Antonietti Markus , Titirici Maria‐Magdalena 
Published: June 2010

AbstractThe synthesis of carbonaceous materials with a high surface density of amino functions for CO2 sorption and sequestration is reported. The amino‐rich carbonaceous materials are characterized by elemental analysis, N2 sorption, scanning and transmission electron microscopy, zeta potential, TGA and FTIR measurements. A detailed discussion on the use of these materials in CO2 capture is provided. The materials show significant sorption capabilities for CO2 (4.3 mmol g−1at −20 °C and 1 bar). Furthermore, they show a high apparent selectivity for CO2 over N2 at both low and high temperatures.
Fractional charge packet counting with constant relative resolution
Authors: Nascetti A. 
Published: June 2010

SUMMARYA charge‐to‐digital converter concept suitable for pixel‐level charge sensitive amplifiers is presented. The circuit implements a technique referred here as fractional charge packet counting, which ensures large dynamic range operation using constant integration time. By means of a particular circuit arrangement a constant number of significant bits is provided as output, thus ensuring a constant relative resolution over the entire dynamic range.A circuit implementing the concepts described above has been designed and simulated. Each block of the circuit is described in details and its characterization is presented. The circuit is capable to convert input currents in the range of 100 fA to 100 nA at 2 ksample/s with a constant resolution of 10 bit without the need of gain switching. Copyright © 2010 John Wiley & Sons, Ltd.
Signal processing electronics for multiple electronic and optical measurements on cells
Authors: Steinkamp John A. , Hiebert Richard D. 
Published: June 2010

AbstractProcessing electronics for flow cytometry applications requiring simultaneous or sequential analysis of multiple electrical and optically sensed signals has been developed. A maximum of six analog signals are input to the processor. A measurement mode selector determines what signals are to be analyzed and the initial timing sequence of sense gates for acquiring signal crest values. Processor signal‐triggering and sense gate time delays are selectable. Logic coincidence‐anticoincidence circuits determine constraints on incoming signals. Gated peak‐sense and hold signals are routed to computer interface electronics for digitizing and are then displayed as frequency distribution histograms using an LSI‐11 computer. Signals also are processed as single parameters, ratios, and gated single parameters for output to a multichannel pulseheight analyzer and cell sorting electronics. The functional features of the processor are described along with examples illustrating simultaneous and sequential analysis of cultured cells stained with fluorescent dyes.
Quantitation of cell concentration using the flow cytometer
Authors: Stewart Carleton C. , Steinkamp John A. 
Published: June 2010

AbstractA simple procedure has been developed to simultaneously measure cell concentration and analyze marker positive cell populations using the flow cytometer. Fluorescent latex particles of known concentration are added to the sample to be analyzed. Marker positive cells and fluorescent particles are then analyzed using flow cytometric methods. Since the particle concentration is known, the number of particles that have accumulated gives the exact volume of the sample analyzed. The concentration of total and marker positive cells that were analyzed then can be calculated. The method will be illustrated using single, dual, and triple laser excitation of cells stained for DNA content in combination with green or red fluorescent spheres. The usefulness of the procedure is demonstrated by counting cells from highly necrotic tumors where large amounts of debris are present.
Optical diffraction as a tool for semiautomatic, quantitative analysis of tissue specimens
Authors: Różycka M. , Lenczowski S. , Sawicki W. , Barańska W. , Ostrowski K. 
Published: June 2010

AbstractOptical diffraction was tested on electron micrographs of normal and malformed myelin sheaths as a method for semiautomatic quantitative analysis of tissue specimens. Both normal and malformed myelin sheaths were chosen for the analysis because of their characteristic internal structure and its alteration as a result of malformation. Optical diffraction patterns were obtained by means of an optical diffractometer coupled with a digital detector. The spacing and arrangement of the components of various types of myelin sheath were automatically calculated and determined and the results were verified with discriminant analysis. Out of 27 parameters of the radial and out of 25 parameters of the angular distributions of diffracted light intensity, 6 and 11, respectively, were found to have good discriminative power and were used for classification of myelin sheaths. The accuracy of automatic classification was tested by comparison with myelin sheath types of known origin. The samples visually similar by their appearance, e.g. control and regenerating myelin sheaths, were automatically classified with accuracy of 69%, whereas others were classified appropriately with 88–100% accuracy. It is believed that this kind of analysis may successfully be applied for specimens of other tissues and/or organs.
Applications of flow cytometry on bacteria: Cell cycle kinetics, drug effects, and quantitation of antibody binding
Authors: Steen Harald B. , Boye Erik , Skarstad Kirsten , Bloom Barry , Godal Tore , Mustafa Salim 
Published: June 2010

AbstractDual parameter flow cytometric analysis of bacteria has been found technically feasible. A microscope based flow cytometer with either a 100 W Hg‐arc or a 5 W Ar laser as the excitation light source was used to record fluorescence and light scatter simultaneously to produce three dimensional histograms correlating the two parameters. Cells of Escherichia coli K‐12 were fixed in ethanol and stained with mithramycin. Fluorescence (DNA)/light scatter histograms of cells in various phases of growth were recorded at a rate of up to 1 × 104 cells/sec with an instrumental resolution corresponding to coefficient of variation < 5%. Similar histograms of cells stained with FITC indicated that light scatter was approximately proportional to total cell protein. Histograms showing the relative cellular contents of DNA and protein in cultures of rapidly growing E. coli were in quantitative agreement with a current model of bacterial growth. Histograms of E. coli in slow growth indicated that a significant portion of the cells were in a nonreplicating phase. Four antibiotics, all ribosomal inhibitors of protein synthesis, were found to affect the cell cycle differently when present in concentrations sufficient to stop cell division. Mycobacterium leprae bacilli were coated with FITC‐labeled M. leprae specific, human antiserum and with a BCG antiserum. The resulting FITC fluorescence/light scatter histograms yielded the amount of antibody per cell as related to cell size thus facilitating a determination of antigenicity per unit cell weight. The results exemplify bacteriological applications of flow cytometry and demonstrate the efficiency of the method in obtaining detailed and precise information on single bacteria in large numbers.
Flow cytometric analysis of cellular DNA in human acute nonlymphatic leukemias and dysmyelopoietic syndromes
Authors: Maiolo A. T. , Foa P. , Mozzana R. , Chiorboli O. , Ciani A. , Maisto A. , Starace G. 
Published: June 2010

AbstractThe proliferation patterns of bone marrow cells from 16 cases of acute nonlymphatic leukemia (ANLL) and 13 of dysmyelopoietic syndromes were analyzed with DNA‐flow cytometry. In order to reduce the contamination by nonproliferating peripheral blood cells, all aspirates were submitted to a density centrifugation step. DNA content measurements were performed with a PHYWE ICP 22 flow system apparatus. The distribution of cells in the cell cycle phases was calculated by means of an automated fitting procedure.No significant difference between the cell cycle distribution in ANLL and dysmyelopoietic syndromes was detectable. No relationship was observed between the size of the S phase compartment and the percentage of blasts in the original samples. Aspirates from ANLL were also cultured in vitro in liquid phase on dialysis membranes. A clear relationship was observed between the size of the phase compartment and in vitro cell growth since, with the exception of one case, all samples with less than 11% cells in S phase failed to proliferate in vitro. The proliferation profile of ANLL cells after 10 days in culture was similar to that of the original samples.
Extraction of morphological features from biological models and cells by fourier analysis of static light scatter measurements
Authors: Burger D. E. , Jett J. H. , Mullaney P. F. 
Published: June 2010

AbstractModels of biological cells of varying geometric complexity were used to generate data to test a method of extracting geometric features from light scatter distributions. Measurements of the dynamic range and angular distribution of intensity and light scatter from these models was compared to the distributions predicted by a complete theory of light scatter (Mie) and by diffraction theory (Fraunhofer). An approximation to the Fraunhofer theory provides a means of obtaining size and shape features from the data by a spectrum analysis. Experimental verification using nucleated erythrocytes as the biological material show the potential application of this method for the extraction of important size and shape parameters from light scatter data.
Multi‐Parameter, computer controlled operation of a FACS II cell sorter
Authors: Peters Donald C. , Dean Phillip N. , Merrill John T. 
Published: June 2010

AbstractThe ease of operation and versatility of a FACS II cell sorter were improved by replacing the original pulse height analyzer (PHA) with a computer‐based dual parameter PHA and a single channel analyzer (SCA). An ND620 LSI‐11 based PHA is now used to generate the sorting decisions. Sorting windows are created by intensifying one or more regions of any shape on the PHA single or dual parameter histograms. For three parameter operation, the third parameter SCA controls the dual parameter information sent to the analyzer. The SCA can also trigger an abort circuit during the PHA 15 microsecond analyzing dead time, improving the purity of the sorted fraction. The electronics that interfaces the new PHA to the sorter replaces all of the original FACS II analog signal processing circuitry with an interchangeable circuit board. The principles involved should apply to any cell sorter.
Data acquisition and control system for multiparameter cell sorting based on DEC LSI‐11 microprocessor
Authors: Voet L. , Kurmann F. J. , Hannig K. 
Published: June 2010

AbstractA computer system has been developed to add data acquisition, display, storage, and processing capability to a multiparameter flow cytometer/sorter. The system can handle one or two parameters in histogram mode. Alternatively one, two or more parameters are stored event‐by‐event on an external storage device in list‐mode with a resolution of 12 bit. The processor can also control cell sorting. Usual multichannel analyzer features are implemented in software, using standard interface boards without special electronics. Data are accepted via Direct Memory Access (DMA), which depends only on hardware. Data acquisition deadtime is nearly independent of software routines such as graphics display and interactive work. Since more than 8000 events/sec are achieved for eight parameter handling, the computer system has capacity for rapid data acquisition. Although there is no need for such high data acquisition rates in present flow cytometry, it gives the advantage of short single event acquisition and longer process control handling.
Flow cytofluorometric analysis of insulin binding and internalization by swiss 3T3 cells
Authors: Murphy Robert F. , Powers Scott , Verderame Michael , Cantor Charles R. , Pollack Robert 
Published: June 2010

AbstractThe binding of a fluorescein‐isothiocyanate derivative of insulin to Swiss 3T3 cells was measured by flow cytometry. The kinetics of the subsequent internalization were also measured; at a concentration of 1 μM labeled insulin approximately 25% of the internalization was insulin‐specific. The kinetics of endocytosis were contrasted to those of fluorescent derivatives of histone and dextran. In addition, the fusion of endocytic vesicles containing insulin or dextran with lysosomes was detected by measuring the pH‐dependent increase in fluorescein fluorescence caused by the addition of chloroquine. The application of these results to the analysis of growth control by insulin and related hormones is discussed.
Regional white matter development in children with autism spectrum disorders
Authors: Carmody Dennis P. , Lewis Michael 
Published: June 2010

AbstractIn this pilot study the severity of autism spectrum disorders (ASD) was associated with alterations in white matter development. Children with ASD and without ASD were assessed by magnetic resonance imaging (MRI) for their myelination development on a regional basis. Measures were obtained in medial frontal cortex, temporal poles, and temporo‐parietal junction in both left and right hemispheres. Children with ASD showed myelination that was greater than expected for their age in both left and right medial frontal cortex and showed myelination that was less than expected in left temporo‐parietal junction. The severity of ASD symptoms, as assessed by the Autism Diagnostic Observation Schedule—Generic, was associated more with left hemisphere alterations than right hemisphere. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 755–763, 2010.
Anion‐Induced Assembly of Hexacoordinate Rare‐Earth(III) Complexes
Authors: Tanase Stefania , Sottini Silvia , Marvaud Valerie , Groenen Edgar J. J. , Chamoreau Lise‐Marie 
Published: June 2010

AbstractRare‐earth(III) complexes of the general formula [RE{(Hsal)3tren}2](CF3SO3)3·nCH3CN, where RE is Eu (1), Gd (2), and Tb (3), and (Hsal)3tren is tris[2‐(salicylideneimino)ethyl]amine, have been synthesized and structurally characterized. X‐ray crystallographic studies show that the rare‐earth(III) center is coordinated by six oxygen atoms that belong to thephenolato groups of two (Hsal)3tren ligand molecules to give an unusual hexacoordinate geometry. The molecular structure is stabilized by strong intramolecular interactions established between the hydrogen atoms located on the three imino nitrogen atoms and the deprotonated phenol oxygen atoms of each ligand. Luminescence studies have indicated the presence of efficient nonradiative deactivation pathways in 1–3, and only a weak ligand emission was observed (λexc = 275 nm, λem = 545 nm) in all cases. Temperature‐dependent magnetic susceptibility studies have shown that crystal field effects are dominant for complex 3, whilst small antiferromagnetic interactions have been observed in 2.
N‐Coordinated [2Fe–2S] and [4Fe–4S] Clusters: Synthesis, Structures and Spectroscopic Characterisation
Authors: Fuchs Michael G. G. , Dechert Sebastian , Demeshko Serhiy , Meyer Franc 
Published: June 2010

AbstractExamples for [2Fe–2S] clusters with non‐chelating N‐coordinating ligands are still relatively rare, and no mixed‐valent [4Fe–4S] cluster with pure N‐donor ligation has hitherto been reported. In the course of synthetic efforts to isolate a biorelevant [2Fe–2S] cluster 2 with 2‐methylindolato capping ligands, the respective [4Fe–4S] cluster 3 was isolated as a by‐product and characterised by X‐ray diffraction. Since 3 represents the first all‐N‐ligated mixed‐valent [4Fe–4S] complex, rational syntheses for 3 as well as for 2 were then developed. Both complexes are quite unstable in solution, but have been characterised as far as possible by a variety of spectroscopic methods including 1H NMR, UV/Vis and Mößbauer.
Spirocycle (SitBu3)6Si9Cl2: The First of Its Kind among Group 14 Elements
Authors: Klapötke Thomas M , Vasisht Sham Kumar , Mayer Peter 
Published: June 2010

AbstractStructural studies on (R*3Si4)2SiCl2, prepared by the reaction of tetrasilatetrahedranide KR*3Si4 with SiCl4, show that the tetrahedral moieties R*3Si4 undergo structural transformation. The molecule exhibits a spiro[4.4]nonasilane network that comprises two homonuclear tricyclo[2.1.0.02,5]pentasilane rings with a common “naked” silicon bridge. The compound shows structural similarities with R*6Si8, which consists of similar rings fused together along an Si–Si bridge. Comparison of valence angles, interplanar angles and bridgehead distances with respect to tricyclo[2.1.0.02,5]pentanes or similar ring systems with heteronuclear group homologues are reported to highlight the influence of bulky supersilyl R* groups in the structure.
Paramagnetic (1,3‐Diborolyl)ruthenium Triple‐Decker Complexes and Transformation into Diamagnetic Complexes Having Bridging 1,3‐Diborafulvene Ligands (Eur. J. Inorg. Chem. 19/2010)
Authors: Mutseneck Elena V. , Wadepohl Hubert , Enders Markus , Kudinov Alexander R. , Siebert Walter 
Published: June 2010

AbstractThe cover picture shows the serendipitous transformation of the yellow into the dark orange triple‐decker sandwich complex by air. The unique B=CH2 group formed strongly leans toward one of the metal atoms. Non‐equivalence of the Cp*Ru groups suggests a bridge inversion, which does not occur below 70 °C. At higher temperatures the signals of the Cp* protons broaden, but coalescence is not reached in toluene. Details are discussed in the article by M. Enders, A. R. Kudinov, W. Siebert et al. on p. 2911 ff.