bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance oriented control over networks: Switching controllers and switched time delay
Authors: Hirche Sandra , Chen Chih‐Chung , Buss Martin
Published: May 2008

The stability and performance of a networked control system (NCS) strongly depends on the communication quality, e.g., the communication time delay. Aiming for performance oriented control over networks in the presence of piecewise constant time delay, two novel control approaches are investigated. In the first approach, the time delay is monitored and an appropriate controller is selected. The second approach is based on the Quality‐of‐Service communication concept, where the time delay is adjustable and related to the network cost. Aiming for an optimal trade‐off between network cost and control performance the controller, together with the time delay, is switched. Both approaches result in a switched system with switched (piecewise constant) delays. Sufficient stability conditions for the resulting switched time delay system are presented using a piecewise continuous Lyapunov‐Razumikhin function. A common Lyapunov function is derived for symmetric systems. The performance benefits for both approaches are demonstrated in numerical examples. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Adaptive control approach to uncertain longitudinal tire slip in traction control of vehicles
Authors: Nakakuki Takashi , Shen Tielong , Tamura Katsutoshi
Published: May 2008

This paper addresses the longitudinal traction control problem of vehicles. A nonlinear control law at the torque level is shown to cope with the unknown tyre reaction force. From a physical consideration of a vehicle, a decoupling controller design is considered, which enables us to make the controller design straightforward. A parameter estimator is introduced to adaptive control of the system with uncertain frictional coefficient. The proposed controller indicates the better control performance than that of a non‐adaptive or a conventional PI controller as evaluated in numerical simulation. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.
Transanal endoscopic microsurgery is a safe and reliable technique even for complex rectal lesions
Authors: Darwood R J , Wheeler J M D , Borley N R
Published: May 2008

Background

Transanal endoscopic microsurgery (TEM) is a minimally invasive technique for the excision of rectal lesions, with lower morbidity and mortality rates than open surgery. Following advances in laparoscopic colorectal surgery and endoscopic mucosal resection, this study evaluated the safety and efficacy of TEM in the treatment of complex rectal lesions.

Methods

All patients were entered into a prospective database. Complex lesions were identified as high (more than 15 cm from anorectal margin), large (maximum dimension over 8 cm), involving two or more rectal quadrants, or recurrent.

Results

Seventy-one lesions (13 carcinomas and 58 tubulovillous adenomas) were identified. The median duration of operation was 60 (interquartile range (i.q.r.) 30–80) min, with an estimated median blood loss of 0 (i.q.r. 0–10) ml. Median hospital stay was 2 (i.q.r. 1–3) days. One patient developed postoperative urinary retention and one returned with rectal bleeding that did not require further surgery. Two patients developed rectal strictures after operation that were dilated successfully. There was no recurrence of benign lesions during a median follow-up of 21 (i.q.r. 6·5–35) months.

Conclusion

TEM is a safe technique with low associated morbidity, even when used to excise complex rectal lesions. As such it remains the treatment of choice for rectal lesions not requiring primary radical resection.
Confinement in Nanopores at the Oxide/Water Interface: Modification of Alumina Adsorption Properties
Authors: Baca Manuel , Carrier Xavier , Blanchard Juliette
Published: May 2008

There is limited knowledge on the influence of the pore size on surface phenomena (adsorption, dissolution, precipitation, etc.) at the oxide/water interface and a better understanding of the space confinement in nanoscale pores should have practical implications in different areas, such as transport of contaminants in the environment or heterogeneous catalyst preparation, to name a few. To investigate the modifications of the oxide adsorption properties at the oxide/water interface in a confined environment, the surface acidobasic and ion adsorption properties of six different aluminas (5 porous commercial aluminas with pore diameters ranging from 25 to 200 Å and 1 non‐porous alumina) were determined by means of acid–base titration and Ni(II) adsorption. It is shown that the confinement has a moderate impact on the alumina adsorption capacity because all materials have similar surface charging behaviours and ion saturation coverages. However, a confined geometry has a much larger impact on the ion adsorption constants, which decrease drastically when the average pore diameter decreases below 200 Å. These results are discussed in terms of nanoscale pore space confinement.
Generation and Reactivity of Enantiomeric (BINOLato)Ni+ Complexes with Chiral Secondary Alcohols in the Gas Phase
Authors: Novara Francesca R. , Gruene Philipp , Schröder Detlef , Schwarz Helmut
Published: May 2008

In the presence of secondary alcohols, electrospray ionization of dilute methanolic solutions of nickel(II) salts and 1,1′‐bis‐2‐naphthol (BINOL) leads to complexes of the formal composition [(BINOLato)Ni(CH3CH(OH)R)]+ (BINOLato refers to a singly deprotonated (R)‐ or (S)‐1,1′‐bis‐2‐naphthol ligand; R=CH3, C2H5, n‐C3H7, n‐C4H9, n‐C5H11, n‐C6H13, c‐C6H11, and C6H5). Upon collision‐induced dissociation, each mass‐selected nickel complex either loses the entire secondary alcohol ligand or undergoes bond activation followed by elimination of the corresponding ketone, as revealed by deuterium labeling. When enantiomeric BINOLato ligands (R or S) are combined with chiral secondary alcohols (R or S), differences in the branching ratios between these channels for the two stereoisomers of the secondary alcohols provide insight into the chiral discrimination operative in the CH‐ and OH‐bond activation processes. For saturated alkan‐2‐ols, the chiral discrimination is low, and if any preference is observed at all, ketone elimination from the homochiral complexes (R,R and S,S) is slightly favored. In contrast, the diastereomeric (BINOLato)Ni+ complexes of 1‐phenylethanol exhibit preferential ketone losses for the heterochiral systems (S,R and R,S).
Spectroelectrochemical and Computational Studies on the Mechanism of Hypoxia Selectivity of Copper Radiopharmaceuticals
Authors: Holland Jason P. , Barnard Peter J. , Collison David , Dilworth Jonathan R. , Edge Ruth , Green Jennifer C. , McInnes Eric J. L.
Published: May 2008

Detailed chemical, spectroelectrochemical and computational studies have been used to investigate the mechanism of hypoxia selectivity of a range of copper radiopharmaceuticals. A revised mechanism involving a delicate balance between cellular uptake, intracellular reduction, reoxidation, protonation and ligand dissociation is proposed. This mechanism accounts for observed differences in the reported cellular uptake and washout of related copper bis(thiosemicarbazonato) complexes. Three copper and zinc complexes have been characterised by X‐ray crystallography and the redox chemistry of a series of copper complexes has been investigated by using electronic absorption and EPR spectroelectrochemistry. Time‐dependent density functional theory (TD‐DFT) calculations have also been used to probe the electronic structures of intermediate species and assign the electronic absorption spectra. DFT calculations also show that one‐electron oxidation is ligand‐based, leading to the formation of cationic triplet species. In the absence of protons, metal‐centred one‐electron reduction gives the reduced anionic copper(I) species, [CuIATSM]−, and for the first time it is shown that molecular oxygen can reoxidise this anion to give the neutral, lipophilic parent complexes, which can wash out of cells. The electrochemistry is pH dependent and in the presence of stronger acids both chemical and electrochemical reduction leads to quantitative and rapid dissociation of copper(I) ions from the mono‐ or diprotonated complexes, [CuIATSMH] and [CuIATSMH2]+. In addition, a range of protonated intermediate species have been identified at lower acid concentrations. The one‐electron reduction potential, rate of reoxidation of the copper(I) anionic species and ease of protonation are dependent on the structure of the ligand, which also governs their observed behaviour in vivo.
Acyclic Diene Metathesis with a Monomer from Renewable Resources: Control of Molecular Weight and One‐Step Preparation of Block Copolymers
Authors: Rybak Anastasiya , Meier Michael A. R.
Published: May 2008

The preparation of a long‐chain aliphatic α,ω‐diene from plant oil derivatives and its subsequent polymerization through acyclic diene metathesis (ADMET) is described. The ADMET bulk polymerization of the thus‐obtained monomer, undecyl undecenoate, was investigated and optimized by applying ruthenium‐based metathesis catalysts from Grubbs and Hoveyda–Grubbs, leading to high‐molecular‐weight polyesters. Moreover, by applying different amounts of methyl 10‐undecenoate as a chain stopper in this ADMET step growth polymerization, the molecular weight of the resulting polyester could be tuned in a range from approximately 10 to 45 kDa. Finally, the application of a poly(ethylene glycol) methyl ether acrylate as the chain stopper led to the preparation of ABA triblock copolymers in a one‐step, one‐pot procedure.
Observation of calcium microdomains at the uropod of living morphologically polarized human neutrophils using flash lamp‐based fluorescence microscopy
Authors: Clark Andrea J. , Petty Howard R.
Published: May 2008

The present study outlines improved strategies for ratiometric imaging of cell calcium using a flash lamp‐based excitation method and its application to neutrophil polarization. A brief (∼6 μs) and intense flash was used to excite the Fluo‐4 and Fura Red calcium dye combination in morphologically polarized human neutrophils. These illumination conditions do not allow the dye or calcium ions to diffuse significant distances during the exposure period. Buffer conditions such as pH, pyruvate concentration, and glucose levels were adjusted to more faithfully replicate these parameters in sepsis patients. Fluorescence images at both dyes' emission wavelengths were simultaneously collected using a Dual‐View apparatus and an ICCD camera. The ratiometric images, when viewed as single frames or averaged image stacks, clearly demonstrated high calcium probe ratios at the uropod and comparatively low ratios at the cell body that were not evident using conventional imaging methods with longer exposure times. Calcium signaling at the uropod is likely associated with cytoskeletal remodeling during cell motility. © 2008 International Society for Advancement of Cytometry
Sequential univariate gating approach to study the effects of erythropoietin in murine bone marrow
Authors: Achuthanandam Ram , Quinn John , Capocasale Renold J. , Bugelski Peter J. , Hrebien Leonid , Kam Moshe
Published: May 2008

Analysis of multicolor flow cytometric data is traditionally based on the judgment of an expert, generally time consuming, sometimes incomplete and often subjective in nature. In this article, we investigate another statistical method using a Sequential Univariate Gating (SUG) algorithm to identify regions of interest between two groups of multivariate flow cytometric data. The metric used to differentiate between the groups of univariate distributions in SUG is the Kolmogorov‐Smirnov distance (D) statistic. The performance of the algorithm is evaluated by applying it to a known three‐color data set looking at activation of CD4+ and CD8+ lymphocytes with anti‐CD3 antibody treatment and comparing the results to the expert analysis. The algorithm is then applied to a four‐color data set used to study the effects of recombinant human erythropoietin (rHuEPO) on several murine bone marrow populations. SUG was used to identify regions of interest in the data and results compared to expert analysis and the current state‐of‐the‐art statistical method, Frequency Difference Gating (FDG). Cluster analysis was then performed to identify subpopulations responding differently to rHuEPO. Expert analysis, SUG and FDG identified regions in the data that showed activation of CD4+ and CD8+ lymphocytes with anti‐CD3 treatment. In the rHuEPO treated data sets, the expert and SUG identified a dose responsive expansion of only the erythroid precursor population. In contrast, FDG resulted in identification of regions of interest both in the erythroid precursors as well as in other bone marrow populations. Clustering within the regions of interest defined by SUG resulted in identification of four subpopulations of erythroid precursors that are morphologically distinct and show a differential response to rHuEPO treatment. Greatest expansion is seen in the basophilic and poly/orthochromic erythroblast populations with treatment. Identification of populations of interest can be performed using SUG in less subjective, time efficient, biologically interpretable manner that corroborates with the expert analysis. The results suggest that basophilic erythroblasts cells or their immediate precursors are an important target for the effects of rHuEPO in murine bone marrow. The MATLAB implementation of the method described in the article, both experimental data and other supplemental materials are freely available at http://web.mac.com/acidrap18. © 2008 International Society for Advancement of Cytometry
Complexes of Yb3+ with EDTA and CDTA – Molecular and Electronic Structure
Authors: Janicki Rafał , Starynowicz Przemysław , Mondry Anna
Published: May 2008

Two Yb3+ compounds, [C(NH2)3]2[Yb(EDTA)(H2O)2]ClO4·6H2O and [C(NH2)3][Yb(CDTA)(H2O)2]·4H2O, where EDTA is the ethylenediaminetetraacetate anion and CDTA is the trans‐1,2‐diaminecyclohexane‐N,N,N′,N′‐tetraacetate anion, were obtained and their crystal structures and spectroscopic properties were determined. In both compounds, the coordination geometries of the eight‐coordinate Yb3+ ion are very similar. In each case, the inner sphere of the metal ion consists of four carboxyl oxygen atoms, two nitrogen atoms and two water molecules. The complexes were characterized by UV/Vis/NIR absorption at different temperatures and IR spectroscopy. The spectroscopic results revealed high sensitivity of the electronic 4f13 configuration upon minor changes in the coordination geometry around the Yb3+ ion. These data also demonstrate that species present in solutions of Yb3+–EDTA are similar to those found in the crystal, whereas in solutions of Yb3+–CDTA an equilibrium between at least two different forms exists. For the Yb3+–EDTA complex in solution and in the crystalline state, a charge‐transfer transition was detected. Theoretical calculations revealed its complicated (Yb → ligand and ligand → Yb) character.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Donor‐Functionalised N‐Heterocyclic Carbene Complexes of Group 9 and 10 Metals in Catalysis: Trends and Directions
Authors: Normand Adrien T. , Cavell Kingsley J.
Published: May 2008

This review focuses on the latest advances in homogeneous catalysis with donor‐functionalised (donor = C, N, O, S or P) N‐heterocyclic carbene complexes of group 9 and 10 metals. The applications of such complexes to C–C coupling reactions, alkyne and ketone hydrosilylation, olefin polymerisation, transfer hydrogenation, asymmetric hydrogenation and other catalysed reactions are discussed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Kinetic parameter determination of vegetable oil oxidation under Rancimat test conditions
Authors: Farhoosh Reza , Niazmand Razieh , Rezaei Mitra , Sarabi Mahboobe
Published: May 2008

In this research, five different vegetable oils were oxidized at four different temperatures (373, 383, 393, and 403 K) under Rancimat test conditions. An increasing rate of oxidation could be observed as temperature increased. The natural logarithms of the kinetic rate constant (k value) varied linearly with respect to temperature, with the temperature coefficients (TCoeff) ranging from 6.95×10–2 to 7.40× 10–2 K–1 for the vegetable oils. On the basis of the Arrhenius equation and the activated complex theory, frequency factors (A), activation energies (Ea), Q10 numbers, activation enthalpies (ΔH++), and activation entropies (ΔS++) for oxidative stability of the vegetable oils were calculated. The A, Ea, Q10, ΔH++, and ΔS++ values for the vegetable oils ranged from 6.38×103 to 28.03×103 h–1, from 86.86 to 92.42 kJ/mol, from 2.08 to 2.18, from 83.64 to 89.20 kJ/mol, and from –116.66 to –104.35 J/mol K, respectively.
Metathesis as a versatile tool in oleochemistry
Authors: Rybak Anastasiya , Fokou Patrice A. , Meier Michael A. R.
Published: May 2008

Olefin metathesis, awarded with the Nobel Prize in Chemistry 2005 for Chauvin, Grubbs and Schrock, has emerged as a powerful tool for organic as well as polymer chemistry. In oleochemistry, this reaction is well known and has been applied for many decades. Examples include the functionalization of the double bonds of different oleochemicals or the (direct) polymerization of plant oils via metathesis. More recent developments, particularly the development of better and more robust catalysts, allow for highly efficient cross‐metathesis reactions opening new possibilities for the direct introduction of chemical functionalities. Within this contribution, the development of metathesis in oleochemistry will be discussed, covering self‐metathesis as well as more recent developments in the field of cross‐metathesis that lead to desired platform chemicals.
Stable Triazenes Derived from 2‐Alkylaminonaphthalenes and 5‐Nitrobenzo[c]‐1,2‐thiazole‐3‐diazonium Hydrogensulfate
Authors: Přikryl Josef , Macháček Vladimír , Jansa Petr , Svobodová Markéta , Růžička Aleš , Nachtigall Petr , Černý Michal
Published: May 2008

A calculation using the DFT method confirmed that the extraordinary stability of the triazenes formed by an azo coupling reaction of 5‐nitrobenzo[c]‐1,2‐thiazole‐3‐diazonium with primary or secondary aromatic amines is caused by the fact that these substances are protonated at the heterocyclic nitrogen atom and not at the nitrogen atom of the triazene grouping –N=N–N(R)Ar. Stable triazenes are also formed by reaction of 5‐nitrobenzo[c]‐1,2‐thiazole‐3‐diazonium with 2‐alkylaminonaphthalenes. In the cases of the azo coupling reaction with 2‐methylamino‐ and 2‐ethylaminonaphthalene, the content of triazenes is almost 50 % in the product mixture with the isomeric azo compounds. The structures of the triazenes were confirmed by X‐ray analysis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Determination of trace levels of benzodiazepine in urine using capillary electrochromatography‐time of flight mass spectrometry
Authors: Blas Maximilien , McCord Bruce R.
Published: May 2008

This paper details a method for the separation and determination of ten benzodiazepines in urine using CEC‐MS(TOF) and an hexyl acrylate‐based porous monolith. The TOF mass spectrometer provides an exact mass of protonated benzodiazepines to three decimal places (1–6 ppm). This high selectivity along with the CEC separation, provides an effective method for the identification of benzodiazepines. Linearity is satisfactory for all compounds in the concentration range of 25–500 ng/mL for lorazepam and 12.5–500 ng/mL for the others. The RSDs are between 1.4–2.3% for retention times and 1.1–9.2% for relative areas. Using the monolithic stationary phase, a preconcentration step is achievable and permits an 75–140‐fold improvement in sensitivity. This strategy permits the quantification of these drugs down to 1 ng/mL in urine. This method was used for the analysis of benzodiazepines in spiked urine samples.
The role of post‐translational modifications for learning and memory formation
Authors: Sunyer Berta , Diao Weifei , Lubec Gert
Published: May 2008

Learning and memory depend on molecular mechanisms involving the protein machinery. Recent evidence proposes that post‐translational modifications (PTMs) play a major role in these cognitive processes. PTMs including phosphorylation of serine, threonine, and tyrosine are already well‐documented to play a role for synaptic plasticity of the brain, neurotransmitter release, vesicle trafficking and synaptosomal or synaptosomal‐associated proteins are substrates of a series of specific protein kinases and their counterparts, protein phosphatases. But protein phosphorylation is only one out of many possible PTMs and first work shows a role of palmitoylation as well as glycosylation for proteins involved in memory formation. Recent technology may now allow reliable detection and even quantification of PTMs of proteins involved in the cognitive system. This will contribute to the understanding of mechanisms for learning and memory formation at the chemical level and has to complement determination of protein levels and indeed determination of protein expression per se generates limited information. The many other PTMs expected including protein nitrosylation and alkylation will even represent targets for pharmacological interventions but in turn increase the complexity of the system. Nevertheless, determination of the presence and the function of PTMs is mandatory and promising cognitive research at the protein chemical level.
Capillary electrophoresis‐mass spectrometry – a fast and reliable tool for the monitoring of milk adulteration
Authors: Műller Lukáš , Barták Petr , Bednář Petr , Fryšová Iveta , Ševčík Juraj , Lemr Karel
Published: May 2008

The development of a rapid, simple and accurate analytical method aimed at the detection and quantification of bovine milk in either ovine or caprine milk samples by means of CE‐MS analyses of whey proteins with high‐ionic strength and presence of acidic running buffer is described. The high‐ionic strength buffer was used in order to minimize the problems with the adsorption of the proteins onto the fused‐silica capillary wall. The acidic running electrolyte, pH 1.9, was used to support the production of positive ions in electrospray. Highly linear dependences of the ratio of the sum of non‐bovine β‐lactoglobulins (ovine or caprine) to the total β‐lactoglobulins in milk mixture (bovine plus ovine or bovine plus caprine) vs. the volume percentage of added bovine milk in ovine (or caprine) milk were obtained. This technique allowed the fast and reliable evaluation of milk adulteration. The amount of bovine milk added into the “non‐bovine” ones can be well within the concentration range of 5–95%.
Analysis of immune complexes by capillary electrophoresis
Authors: Shihabi Zak K.
Published: May 2008

A simple method for immune complexes (IC) analysis by CE is described. This method combines the ease of precipitation of the IC by polyethylene glycol with the separation power of CE. The advantage of this method is a better quantitation of the IC, since it corrects and eliminates the interferences from other serum proteins. It also reveals the composition (monoclonality) of the precipitate. Three types of IC have been detected in this method: monoclonal, polyclonal and mixed (mono‐polyclonal) IC. Furthermore, the method is rapid and simple.
Combined capillary electrophoresis and DNA‐fluorescence in situ hybridization for rapid molecular identification of Salmonella Typhimurium in mixed culture
Authors: Lantz Andrew W. , Brehm‐Stecher Byron F. , Armstrong Daniel W.
Published: May 2008

CE, long a staple in analytical chemistry for molecular separations, has recently been adapted for separating heterogeneous mixtures of microbial cells based on intrinsic differences in cell morphology and surface charge. In this application, CE enables effective separations of both relatively broad categories of cells, as well as of more similar cell types. As a phenotypic approach, CE may be less applicable to certain populations, including those comprised of pleiomorphic cells or chain‐forming cells, where differences in cell size, shape, or chain length may lead to broad, “unfocusable” distributions in cell surface charge. At the other end of the spectrum, closely related species having similar surface charge profiles may not be separable via CE alone. Successful combination of microbial CE with a compatible method for generating cell‐specific signals could address these limitations, increasing the diagnostic power of this approach. Fluorescence in situ hybridization (FISH) is a rapid molecular technique for fluorescence‐based labeling of whole target cells. In this work, we combined a simple CE‐based presence/absence test with FISH to develop a bacterial detection assay having an additional “layer” of molecular specificity. Using this approach, we were able to differentiate Salmonella Typhimurium from Escherichia coli in mixed populations via CE. Both hybridizations and CE run times were short (10–15 min), bacterial populations were highly focused (∼2–3 s peak width) and there was no need for a posthybridization wash step. As few as three injected cells of S. Typhimurium were detected against a background of ∼300 injected E. coli cells, suggesting the possibility for single‐cell detection of pathogens using this technique. This proof of concept study highlights the potential of CE‐FISH as a promising new tool for molecular detection of specific bacterial cells within mixtures of closely related, physiologically inseparable populations.
Downregulation of two isoforms of ubiquitin carboxyl‐terminal hydrolase isozyme L1 correlates with high metastatic potentials of human SN12C renal cell carcinoma cell clones
Authors: Tanaka Toshiyuki , Kuramitsu Yasuhiro , Fujimoto Masanori , Naito Seiji , Oka Masaaki , Nakamura Kazuyuki
Published: May 2008

Proteomic differential display analysis was performed on human renal cell carcinoma cell SN12C clones having different metastatic potentials by using 2‐DE and LC‐MS/MS. The SN12C cell clones were SN12C parent cell line, SN12C‐clone 2, SN12C‐clone 4, and SN12C‐PM6. The SN12C parent cell line was established from an HRCC surgical specimen. SN12C‐clone 4 has lower, and SN12C‐clone 2 and SN12C‐PM6 have higher metastatic potential than SN12C parent cells. We found eight protein spots whose expression level was different between low metastatic clones and high metastatic clones. The protein expression of three appeared to be higher in high metastatic clones than low metastatic clones, and that of other five protein spots appeared to be lower in high metastatic clones than low metastatic clones. These spots were selected, digested and analyzed by LC‐MS/MS analysis, and they were identified by peptide sequencing tag. In high metastatic potential clones, two isoforms of ubiquitin carboxyl‐terminal hydrolase isozyme L1 (UCH‐L1) were downregulated. These results suggest that UCH‐L1 expression seems to be associated with the metastatic potential of HRCC SN12C cell clones.
Electrophoretic evidence for the presence of structural isoforms specific for the IgG2 isotype
Authors: Guo Amy , Han Mei , Martinez Theresa , Ketchem Randal R. , Novick Shawn , Jochheim Claudia , Balland Alain
Published: May 2008

Recombinant monoclonal antibodies of therapeutic interest were analyzed by a nonreduced CE‐SDS (nrCE‐SDS) method developed for the evaluation of size‐based variants. We found that immunoglobulins analyzed by this technique exhibited different behavior depending on their subclasses. Under nrCE‐SDS conditions, IgG1 molecules were separated in a well‐resolved, single peak, whereas IgG2 molecules were consistently separated as a doublet. Investigation of these isoforms showed that they were structurally different, and that the difference was not caused by cell culture condition, glycosylation structure, or recombinant expression system. Commercially available IgG2 affinity‐purified from human plasma also showed the presence of structural isoforms. The structural isoforms remained present under pH‐ and temperature‐stressed conditions. Application of a mild cysteine/cystine redox potential converted the main peak doublet into a single peak, indicating that these isoforms were disulfide bond‐related species. Bioactivity measured before and after application of a redox potential gave similar values, indicating that the structural isoforms have comparable potency. The nrCE‐SDS technique described here demonstrated a unique capability to resolve IgGs, leading to the discovery of novel structural isoforms specific to the IgG2 isotype.
Live‐cell imaging reveals sustained centromere binding of CENP‐T via CENP‐A and CENP‐B
Authors: Hellwig D. , Münch S. , Orthaus S. , Hoischen C. , Hemmerich P. , Diekmann S.
Published: May 2008

At the centromere, a network of proteins, the kinetochore, assembles in order to grant correct chromatin segregation. In this study the dynamics and molecular interactions of the inner kinetochore protein CENP‐T were analyzed employing a variety of fluorescence microscopy techniques in living human cells. Acceptor‐bleaching FRET indicates that CENP‐T directly associates with CENP‐A and CENP‐B. CENP‐T exchange into centromeres is restricted to the S‐phase of the cell cycle as revealed by FRAP, suggesting a coreplicational loading mechanism, as we have recently also demonstrated for CENP‐I. These properties make CENP‐T one of the basic inner kinetochore proteins with most further proteins binding downstream, suggesting a fundamental role of CENP‐T in kinetochore function. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Human osteoclast formation and activity on a xenogenous bone mineral
Authors: Perrotti Vittoria , Nicholls Brian M. , Horton Michael A. , Piattelli Adriano
Published: May 2008

To date, the majority of studies on bone substitute materials have investigated their regenerative properties; however, little is known about their resorption processes, forasmuch as it is believed that the ideal biomaterial for bone regeneration must be completely resorbable. This study is aimed at defining the in vitro resorption potential of human osteoclasts (OCLs) on a xenogenous bone mineral (XBM). Peripheral blood mononuclear cells from healthy volunteers were used to generate OCLs in vitro in the presence of macrophage colony stimulating factor and receptor activator of NF‐κB ligand on bovine bone slices and XBM. By using morphologic and biochemical methods, we observed that OCL formation occurred on XBM and these cells were positive for the major OCL markers. Regarding OCL activity, resorption pits were detected on XBM by reflection and confocal microscopy. However, biochemical analysis revealed that collagen degradation at day 14 and 21 was significantly lower in XBM supernatants when compared to bovine bone, suggesting that XBM underwent a much slower resorption over time. These findings demonstrate that OCLs are generated on, attach to, and resorb XBM though more slowly than native bone, and suggest that cultured human OCLs could be used as a model for comparing resorption rates of bone substitute materials. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
HEMA down‐regulates procollagen α1 type I in human gingival fibroblasts
Authors: Teti Gabriella , Mazzotti Giovanni , Zago Michela , Ortolani Michela , Breschi Lorenzo , Pelotti Susi , Ruggeri Alessandra , Falconi Mirella
Published: May 2008

2‐Hydroxyethyl methacrylate (HEMA) can be released from restorative materials and diffused into the tooth pulp over long periods of time. Although cytotoxicity due to high concentrations of monomers has been well studied, little is known about the risk of chronic toxicity resulting from low concentrations. The purpose of the study was to evaluate the effects of a minor toxic concentration of HEMA in the synthesis and expression of procollagen α1 type I produced by human gingival fibroblasts (HGF). HGF were exposed to 3 mM HEMA from 24 to 96 h. An MTT assay was performed to evaluate cell viability while reverse‐transcriptase polymerase chain reaction (RT‐PCR), real‐time polymerase chain reaction (real‐time PCR), and Western‐blot analysis were carried out to evaluate the variability in the expression and synthesis of procollagen α1. Immunofluorescence was performed to detect the protein inside the cells. The results showed that there was a strong reduction of procollagen α 1 type I expression at 72 and 96 h. These findings demonstrate that, even if it does not reduce cell viability, 3 mM HEMA interferes both with the synthesis of the procollagen α 1 type I protein and its mRNA expression, suggesting that normal cell production and activity are modified by HEMA at concentrations below those which cause acute cytotoxicity. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Cluster analysis of ribotyping profiles of Staphylococcus epidermidis isolates recovered from foreign body‐associated orthopedic infections
Authors: Campoccia Davide , Montanaro Lucio , von Eiff Christof , Pirini Valter , Ravaioli Stefano , Becker Karsten , Arciola Carla Renata
Published: May 2008

Staphylococcus epidermidis is an opportunistic pathogen of major clinical interest for its high prevalence in implant‐associated infections. However, only little information is available on the phylogeny of its major clonal entities and their virulence and resistance markers. Therefore, purpose of this study was to characterize four clusters identified by automated ribotyping of 70 isolates derived from orthopedic, mostly foreign body‐related infections. The ica locus, encoding the polysaccharide intercellular adhesin, the IS256 insertion element as well as the resistance to gentamicin, clindamycin, chloramphenicol, and ciprofloxacin were all traits uniquely observed in two of these clusters. The phylogenetic analysis of the S. epidermidis clusters offered a detailed insight into the clonal origin of exopolysaccharide‐ producing and multiresistant strains with transposons appearing to be actively involved in genetic exchanges. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Synthesis and characterization of L‐tyrosine based polyurethanes for biomaterial applications
Authors: Sarkar Debanjan , Yang Jui‐Chen , Gupta Anirban Sen , Lopina Stephanie T.
Published: May 2008

The use of amino acid based polymers for biomaterial applications enhance biocompatibility and ensure biodegradability. Two polyurethanes based on L‐tyrosine based diphenolic dipeptide, desaminotyrosyl tyrosine hexyl ester as chain extender are synthesized with polyethylene glycol (PEG) and polycaprolactone diol (PCL) as soft segment and hexamethylene diisocyanate as diisocyanate. The chemical structure and molecular characteristics of the polymers were studied by 1H NMR, FTIR, and gel permeation chromatography. Results of DSC and TGA analysis were used for examining the thermal behavior of the polyurethanes. In addition, DSC results were used to analyze the morphology of the polymers, which shows characteristic microphase behavior of the polyurethanes. The tensile properties of the polyurethanes are primarily controlled by the soft segment and are higher in PCL based polymers. Contact angle, water vapor permeation, release of model drug, and water absorption characteristics of the polymers were studied and analyzed in terms of structure of the polyurethanes. In vitro degradation studies show that PEG based polyurethane is more degradable than PCL based polyurethane. The difference in the soft segment structure offers significant variation in the properties of the polyurethanes. These polyurethanes show the potential for use in a variety of biomaterial applications including tissue engineering. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Pareto optimization in computational protein design with multiple objectives
Authors: Suárez María , Tortosa Pablo , Carrera Javier , Jaramillo Alfonso
Published: May 2008

The optimization for function in computational design requires the treatment of, often competing, multiple objectives. Current algorithms reduce the problem to a single objective optimization problem, with the consequent loss of relevant solutions. We present a procedure, based on a variant of a Pareto algorithm, to optimize various competing objectives in protein design that allows reducing in several orders of magnitude the search of the solution space. Our methodology maintains the diversity of solutions and provides an iterative way to incorporate automatic design methods in the design of functional proteins. We have applied our systematic procedure to design enzymes optimized for both catalysis and stability. However, this methodology can be applied to any computational chemistry application requiring multi‐objective combinatorial optimization techniques. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008
Molecular modeling of A1and A2Aadenosine receptors: Comparison of rhodopsin‐ and β2‐adrenergic‐based homology models through the docking studies
Authors: Yuzlenko Olga , Kieć‐Kononowicz Katarzyna
Published: May 2008

Adenosine receptors (ARs) are members of the superfamily of G protein‐coupled receptors. The homology models of adenosine A1and A2Areceptors were constructed. The high‐resolution X‐ray structure of bovine rhodopsin and crystal structure of β2‐adrenergic receptor were used as templates. The binding sites of the A1and A2AARs were constructed by using data obtained from mutagenesis experiments as well as docking simulations of the respective AR antagonsistsDPCPXandXAC. To compare rhodopsin‐ and β2‐adrenergic‐based models, the binding mode of A1(KW‐3902,LUF‐5437) and A2A(KW‐6002,ZM‐241385) ARs antagonists were also examined. The differences in the binding ability of both models were noted during the study. The β2‐adrenergic‐based A2AAR model was much more capable to stabilize the ligand in the binding site cavity than the corresponding rhodopsin‐based A2AAR model, however, such differences were not so clear in case of A1AR models. It was suggested that for the A1AR it is possible to use the crystal structure of rhodopsin as a template as well as β2‐adrenergic receptor, but for A2AAR, with the now available β2‐adrenergic receptor X‐ray structure, docking studies should be avoided on the rhodopsin‐based model. However, taking into account that the β2AR shares about 31% of the residues with the AR in comparison to 21% in case of bRho, we suggest using β2‐adrenergic‐based models for the A1and A2AARs for further in silico ligand screening also because of their generally better ability to stabilize ligands inside the binding pocket. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Efficient electronic integrals and their generalized derivatives for object oriented implementations of electronic structure calculations
Authors: Flocke N. , Lotrich V.
Published: May 2008

For the new parallel implementation of electronic structure methods in ACES III (Lotrich et al., in preparation) the present state‐of‐the‐art algorithms for the evaluation of electronic integrals and their generalized derivatives were implemented in new object oriented codes with attention paid to efficient execution on modern processors with a deep hierarchy of data storage including multiple caches and memory banks. Particular attention has been paid to define proper integral blocks as basic building objects. These objects are stand‐alone units and are no longer tied to any specific software. They can hence be used by any quantum chemistry code without modification. The integral blocks can be called at any time and in any sequence during the execution of an electronic structure program. Evaluation efficiency of these integral objects has been carefully tested and it compares well with other fast integral programs in the community. Correctness of the objects has been demonstrated by several application runs on real systems using the ACES III program. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008
The role of organizational cultures in information‐systems security management: A goal‐setting perspective
Authors: Koskosas Ioannis V. , Charitoudi Georgia , Louta Malamati
Published: May 2008

The aim of this research is to investigate the role of strong organizational cultures in setting information‐systems security goals. In doing so, we explore and discuss the concept of culture within three financial organizations with different social and organizational structures, and seek to demonstrate the importance of having a cohesive culture in efficiently setting information‐security goals. The relationship between goal setting, culture strength, and performance is also discussed, as there have been studies that indirectly indicate that such a relationship may exist. The contribution of this work to interpretive information‐systems research consists of its study of culture and goal setting in a security‐management context, and its grounding within an interpretive epistemology. In addition, this research promotes an interdisciplinary and interorganizational theory to foster dialogue that transcends industry‐specific contexts and explores different organizational practices that can improve leadership's role in human life.
Symposium. Effects of affect and traits in U.S. presidential candidates. Leadership quality and follower affect. Role of measurement error in assessing qualities of presidential candidates. The authors respond. Perception is reality—in the minds of the voters: An interview with David Albritton
Authors: Korukonda Appa Rao , Pielstick C. Dean , Sloboda Brian , Albritton M. David , Oswald Sharon L. , Anderson Joseph S. , Ament Allan
Published: May 2008

In the Winter, 2008 issue of JLS, authors David Albritton, Sharon
Oswald, and Joseph Anderson presented their research regarding the relationship
between perceived leader traits of U.S. presidential contenders and both voter‐perceived
leadership quality and behavior. The Abstract from that article
serves as an introduction for the three responses from Appa Rao Korukonda,
C. Dean Pielstick, and Brian Sloboda. To further enhance the discussion,
Albritton, Oswald, and Anderson revisit their work. An interview conducted by
Allan Ament with David Albritton concludes this Symposium.
Patterns of morphospace occupation and mechanical performance in extant crocodilian skulls: A combined geometric morphometric and finite element modeling approach
Authors: Pierce Stephanie E. , Angielczyk Kenneth D. , Rayfield Emily J.
Published: May 2008

Extant and fossil crocodilians have long been divided into taxonomic and/or ecological groups based on broad patterns of skull shape, particularly the relative length and width of the snout. However, these patterns have not been quantitatively analyzed in detail, and their biomechanical and functional implications are similarly understudied. Here, we use geometric morphometrics and finite element analysis to explore the patterns of variation in crocodilian skull morphology and the functional implications of those patterns. Our results indicate that skull shape variation in extant crocodiles is much more complex than previously recognized. Differences in snout length and width are the main components of shape variation, but these differences are correlated with changes in other regions of the skull. Additionally, there is considerable disparity within general classes such as longirostrine and brevirostrine forms. For example, Gavialis and Tomistoma occupy different parts of morphospace implying a significant difference in skull shape, despite the fact that both are traditionally considered longirostrine. Skull length and width also strongly influence the mechanical performance of the skull; long and narrow morphotypes (e.g., Tomistoma) experience the highest amount of stress during biting, whereas short and broad morphotypes (e.g., Caiman latirostris) experience the least amount of stress. Biomechanical stress and the hydrodynamic properties of the skull show a strong relationship with the distribution of crocodilians in skull morphospace, whereas phylogeny and biogeography show weak or no correlation. Therefore, ecological specializations related to feeding and foraging likely have the greatest influence on crocodilian skull shape. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.
The postorbital palatoquadrate articulation in elasmobranchs
Authors: Maisey John G.
Published: May 2008

Although modern hexanchiforms are the only extant elasmobranchs with a postorbital articulation, according to most morphological and molecular cladistic analyses they are not basal, suggesting that Huxley (1876Proc Zool Soc 1876;24–59) correctly identified this articulation as “an altogether secondary connection.” A postorbital articulation is present in many Paleozoic sharks, but differs from that found in hexanchiforms in its morphology, topographic position on the braincase, and inferred ontogenetic origins. Furthermore, a postorbital articulation is absent in hybodonts (the putative extinct sister group to neoselachians). It is proposed that the term amphistylic should be restricted to the modern hexanchiform condition, where the articular facet is located on the primary postorbital process. An identical articulation probably existed in some extinct galeomorphs (e.g., †Synechodus dubrisiensis, †Paraorthacodus), but is not widespread within elasmobranchs generally. The termarchaeostylic(“ancient pillar”) is proposed here for the suspensorial arrangement in Paleozic sharks with a postorbital articulation on the ventrolateral part of the lateral commissure. Such an articulation is not known in other gnathostomes and may represent a basal chondrichthyan synapomophy (especially if †Pucapampellais a stem chondrichthyan), suggesting that the autodiastylic pattern is not primitive for chondrichthyans and that holocephalans have secondarily lost a postorbital articulation. The amphistylic condition may have arisen from the archaeostylic, or it could have been acquired independently within neoselachians, but in either case it is most parsimoniously viewed as apomorphic. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.
Evolution of ochratoxin A content during red and rose vinification
Authors: Lasram Salma , Mani Arij , Zaied Chiraz , Chebil Samir , Abid Salwa , Bacha Hassen , Mliki Ahmed , Ghorbel Abdelwahed
Published: May 2008

BACKGROUND: This work aims to investigate the effects of the common vinification steps on the fate of the ochratoxin A (OTA) during wine making. Two assays of red and rose microvinification, with artificially contaminated grapes, were performed. The content of this mycotoxin was also monitored throughout the process of red wine making from naturally contaminated grapes in a winery.

RESULTS: The results from the different assays revealed that the maceration of pomace have a significant effect on the increase of OTA content in red wine (P < 0.05) whereas the alcoholic fermentation had a reducing effect. However, the spontaneous malolactic fermentation showed no significant effect on the OTA content in wine (P > 0.05). Storage of red wine in tanks followed by draining caused a significant decrease of OTA of about 55%. Clarification with a gelatin oenological fining agent contributed to the removal of up to 58% of OTA from red wine.

CONCLUSION: Overall, a consistent decrease in OTA concentration was noticed throughout either red or rose vinification. This work has contributed to the understanding of the fate of OTA during different vinification processes, especially from naturally contaminated grapes. Copyright © 2008 Society of Chemical Industry