bluuebunny/crossref_metadata_2025 huggingface dataset:
Mono‐, Di‐, Tri‐ and Tetranuclear Rare Earth Complexes Obtained Using a Moderately Bulky Aryloxide Ligand
Authors: Deacon Glen B. , Junk Peter C. , Moxey Graeme J.
Published: October 2009

Redox transmetallation ligand exchange reactions involving a rare earth metal, 2,4,6‐trimethylphenol (HOmes), and a diarylmercurial afford rare earth aryloxo complexes, which are structurally characterized. Both the lanthanoid contraction and the identity of the reaction solvent are found to influence the outcome of the reactions. Using THF in the reaction affords a dinuclear species [Ln2(Omes)6(thf)4]⋅2THF (Ln=La 1, Nd 2) for the lighter rare earth metals, while a mononuclear species [Ln(Omes)3(thf)3] (Ln=Sm 3, Tb 5, Er 6, Yb 7, Y 8) is obtained for the heavier rare earth elements. Surprisingly, there is no change in metal coordination number between the two structural motifs. A divalent trinuclear linear complex [Eu3(Omes)6(thf)6] 4 is obtained for Eu, and features solely bridging aryloxide ligands. Using DME as the reaction solvent affords [La(Omes)3(dme)2] 9 from the reaction mixture, and [Ln2(Omes)6(dme)2]⋅PhMe (La 10, Nd 11) and [Y(Omes)3(dme)2] 14 following crystallization of the crude product from toluene. The dinuclear species [Eu2(Omes)4(dme)4] 12 contains two unidentate and two chelating DME ligands, and contrasts the linear structure of 4. Treatment of HOmes and HgPh2 with Yb metal in DME affords the mixed valent YbII/III complex [Yb2(Omes)5(dme)2] 13, which is stabilized by an intramolecular π‐Ph–Yb interaction, and is a rare example of a mixed valent rare earth aryloxide. Treatment of Er metal with HOmes at elevated temperature (solvent free) affords the homoleptic [Er4(Omes)12] 15, which consists of a tetranuclear array of Er atoms arranged in a ‘herringbone’ fashion; the structure is stabilized by intramolecular π‐Ph–Er interactions. Reaction of La metal with HOmes under similar conditions yields toluene insoluble “La(Omes)3”, which affords 1 following extraction with THF.
The role of experience in the Gambler's Fallacy
Authors: Barron Greg , Leider Stephen
Published: October 2009

Recent papers have demonstrated that the way people acquire information about a decision problem, by experience or by abstract description, can affect their behavior. We examined the role of experience over time in the emergence of the Gambler's Fallacy in binary prediction tasks. Theories of the Gambler's Fallacy and models of binary prediction suggest that recency bias, elicited by experience over time, may play a significant role. An experiment compared a condition where participants sequentially predicted the colored outcomes of a virtual roulette wheel spin with a condition where the wheel's past outcomes were presented all at once. In a third condition outcomes were presented sequentially in an automatic fashion without intervening predictions. Subjects were yoked so that the same history of outcomes was observed in all conditions. The results revealed the Gambler's Fallacy when outcomes were experienced (with or without predictions). However, the Gambler's Fallacy was attenuated when the same outcomes were presented all at once. Observing the Gambler's Fallacy in the third condition suggests that the presentation of information over time is a significant antecedent of the bias. A second experiment demonstrated that, while the bias can emerge with an all‐at‐once presentation that makes recent outcomes salient (Burns & Corpus, 2004), the bias did not emerge when the presentation did not draw attention to recent outcomes. Copyright © 2009 John Wiley & Sons, Ltd.
Erschöpfte Literatur. Über das Neue bei Samuel Beckett
Authors: Schäfer Armin
Published: October 2009

Exhausted Literature. The Emergence of the New in Samuel Beckett's Novels and Plays. The article investigates literary subjectivity in some texts by Samuel Beckett. The article proceeds by relating the ways of how narration and speech acts constitute literary subjectivity to the problems of subjectivity that scientific investigations deal with. While successful self‐regulation of the organism nourishes the roots of subjectivity, i. e. the habits, subjectivity decomposes in states of exhaustion, when self‐regulation breaks down. As soon as a certain threshold is transgressed, fatigue sets in, alters the personality and eventually leads to exhaustion – a state, which psychiatrists compare to mental illness. Notwithstanding the different explanations given, scientists agreed about the effects of exhaustion. According to their investigations, the decomposition of personality by exhaustion generally does not involve apathy, withdrawal from activity or termination of movements, but rather mere action. Similarly, in Beckett's novels and plays exhaustion is much more than tiredness, as French philosopher Gilles Deleuze observed. For Beckett, exhaustion is rather the model for both literary innovation and a new concept of subjectivity, which he explores on the basis of a detailed knowledge of physiology, psychology, and psychiatry, but using his own literary means. The exhausted subject is beyond any calculus of activity. It will perform an activity even if he or she makes mistakes or loses control, and will thus act in an unpredictable way. This unpredictable action is not an exception in the continuation of the habits, but rather points to the moment when a new subjectivity emerges. Such new subjectivity surfaces in Beckett's novels and plays in forms of literary innovation.
Homogeneity/Heterogeneity Hypotheses for Standardized Mortality Ratios Based on Minimum Power‐divergence Estimators
Authors: Pardo Leandro , Martín Nirian
Published: October 2009

This paper analyzes the power divergence estimators when homogeneity/heterogeneity hypotheses among standardized mortality ratios (SMRs) are taken into account. A Monte Carlo study shows that when the standard mortality rate is not external, that is it is estimated from the sample data, these estimators have a good performance even for small sample sets and in particular the minimum chi‐square estimators have a better behavior compared to the classical maximum likelihood estimators. In order to make decisions under homogeneity/heterogeneity hypotheses of SMRs we propose some test‐statistics which consider the minimum power divergence estimators. Through a numerical example focused on SMRs of melanoma mortality ratios in different regions of the US, a homogeneity/heterogeneity study is illustrated.
Estimating Antihypertensive Effects of Combination Therapy in an Observational Study Using Marginal Structural Models
Authors: Sugihara Masahiro , Kushiro Toshio , Saito Ikuo , Matsushita Yasuyuki , Hiramatsu Katsutoshi
Published: October 2009

The evaluation of the antihypertensive effect of multiple antihypertensive drugs using data from an observational study requires adjustment for time‐dependent confounders. Marginal structural models (MSMs) have been proposed to address this type of confounding through inverse probability weighting. Generally, the probabilities are estimated using logistic regression models that assume linearity between the logistic link and the predictors, but the linearity might be inaccurate. In this article, we proposed MSMs to assess the blood pressure‐lowering effects of combination therapy with olmesartan medoxomil (OLM) plus calcium channel blockers (CCB) (OLM+CCB) in an observational study of OLM, and extended estimation methods of the probabilities for the MSMs using generalized additive models (GAMs). The estimation using GAMs was suggested to improve the balance of the distributions of confounder values between the therapy groups in the pseudo‐population. We obtained estimated changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) for OLM+CCB combination therapy after 12 wk compared with OLM monotherapy of −4.3 mmHg (95% confidence interval (CI): −7.7 and −0.9 mmHg) and −2.9 mmHg (95% CI: −5.1 and −0.7 mmHg), respectively. The estimated target BP (SBP<140 mmHg and DBP<90 mmHg) achievement rates for OLM+CCB combination therapy and OLM monotherapy were 62.0 and 46.7%, respectively. The results of the MSMs were closer to those in the randomized controlled trial, such as the combination of OLM and amlodipine besylate in controlling high blood pressure study, than those of conventional methods. The proposed MSMs provided useful information to evaluate the effects of combination therapy of antihypertensive drugs in the context of an observational study.
Neighborhood Dependence in Bayesian Spatial Models
Authors: Assunção Renato , Krainski Elias
Published: October 2009

The conditional autoregressive model and the intrinsic autoregressive model are widely used as prior distribution for random spatial effects in Bayesian models. Several authors have pointed out impractical or counterintuitive consequences on the prior covariance matrix or the posterior covariance matrix of the spatial random effects. This article clarifies many of these puzzling results. We show that the neighborhood graph structure, synthesized in eigenvalues and eigenvectors structure of a matrix associated with the adjacency matrix, determines most of the apparently anomalous behavior. We illustrate our conclusions with regular and irregular lattices including lines, grids, and lattices based on real maps.
Electroporation optimization to deliver plasmid DNA into dental follicle cells
Authors: Yao Shaomian , Rana Samir , Liu Dawen , Wise Gary E.
Published: October 2009

Electroporation is a simple and versatile approach for DNA transfer but needs to be optimized for specific cells. We conducted square wave electroporation experiments for rat dental follicle cells under various conditions. These experiments indicated that the optimal electroporation electric field strength was 375 V/cm, and that plasmid concentrations greater than 0.18 μg/μL were required to achieve high transfection efficiency. BSA or fetal bovine serum in the pulsing buffer significantly improved cell survival and increased the number of transfected cells. The optimal pulsing duration was in the range of 45–120 ms at 375 V/cm. This electroporation protocol can be used to deliver DNA into dental follicle cells to study the roles of candidate genes in regulating tooth eruption. This is the first report showing the transfection of dental follicle cells using electroporation. The parameters determined in this study are likely to be applied to transfection of other fibroblast cells.
Mechanistic model for prediction of formate dehydrogenase kinetics under industrially relevant conditions
Authors: Schmidt T. , Michalik C. , Zavrel M. , Spieß A. , Marquardt W. , Ansorge‐Schumacher M. B.
Published: October 2009

Formate dehydrogenase (FDH) from Candida boidinii is an important biocatalyst for the regeneration of the cofactor NADH in industrial enzyme‐catalyzed reductions. The mathematical model that is currently applied to predict progress curves during (semi‐)batch reactions has been derived from initial rate studies. Here, it is demonstrated that such extrapolation from initial reaction rates to performance during a complete batch leads to considerable prediction errors. This observation can be attributed to an invalid simplification during the development of the literature model. A novel mechanistic model that describes the course and performance of FDH‐catalyzed NADH regeneration under industrially relevant process conditions is introduced and evaluated. Based on progress curve instead of initial reaction rate measurements, it was discriminated from a comprehensive set of mechanistic model candidates. For the prediction of reaction courses on long time horizons (>1 h), decomposition of NADH has to be considered. The model accurately describes the regeneration reaction under all conditions, even at high concentrations of the substrate formate and thus is clearly superior to the existing model. As a result, for the first time, course and performance of NADH regeneration in industrial enzyme‐catalyzed reductions can be accurately predicted and used to optimize the cost efficiency of the respective processes. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010
High throughput single cell bioinformatics
Authors: Roach Kenneth L. , King Kevin R. , Uygun Basak E. , Kohane Isaac S. , Yarmush Martin L. , Toner Mehmet
Published: October 2009

Advances in systems biology and bioinformatics have highlighted that no cell population is truly uniform and that stochastic behavior is an inherent property of many biological systems. As a result, bulk measurements can be misleading even when particular care has been taken to isolate a single cell type, and measurements averaged over multiple cell populations in a tissue can be as misleading as the average height at an elementary school. There is a growing need for experimental techniques that can provide a combination of single cell resolution, large cell populations, and the ability to track cells over multiple time points. In this article, a microwell array cytometry platform was developed to meet this need and investigate the heterogeneity and stochasticity of cell behavior on a single cell basis. The platform consisted of a microfabricated device with high‐density arrays of cell‐sized microwells and custom software for automated image processing and data analysis. As a model experimental system, we used primary hepatocytes labeled with fluorescent probes sensitive to mitochondrial membrane potential and free radical generation. The cells were exposed to oxidative stress and the responses were dynamically monitored for each cell. The resulting data was then analyzed using bioinformatics techniques such as hierarchical and k‐means clustering to visualize the data and identify interesting features. The results showed that clustering of the dynamic data not only enhanced comparisons between the treatment groups but also revealed a number of distinct response patterns within each treatment group. Heatmaps with hierarchical clustering also provided a data‐rich complement to survival curves in a dose response experiment. The microwell array cytometry platform was shown to be powerful, easy to use, and able to provide a detailed picture of the heterogeneity present in cell responses to oxidative stress. We believe that our microwell array cytometry platform will have general utility for a wide range of questions related to cell population heterogeneity, biological stochasticity, and cell behavior under stress conditions. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Baculovirus P35 protein: An overview of its applications across multiple therapeutic and biotechnological arenas
Authors: Sahdev Sudhir , Saini Kulvinder Singh , Hasnain Seyed E.
Published: October 2009

Baculovirus immediate early P35 protein is well known for its anti‐apoptotic as well as anti‐oxidant properties. Mechanism of action of P35 involves inhibition of a vast range of initiator to executioner class of caspases. In addition, P35's role in inhibiting oxidant‐induced mitochondrial damage, primarily in the apoptotic pathway, has also been extensively investigated. Elucidation of P35's functions during regulation of programmed cell death (PCD) has led to a renewed focus on exploiting this basic knowledge for clinical and other related applications. This review outlines specific biochemical and genetic pathways where P35 intervenes and regulates rate‐limiting steps in the apoptotic signaling cascade. Research efforts are underway to utilize P35 as an agent in regulating apoptosis and under certain circumstances, also explore the therapeutic potential of its anti‐oxidant features. One of the major outcomes of recent studies include significantly improved effectiveness of cytochrome P450 directed enzyme pro‐drug delivery tools when used in conjunction with P35, which may help in alleviating drug resistance in tumor cells and simultaneously prolonging the cytotoxic effects of anti‐cancer drugs. Moreover, applied research carried out recently in the fields of diabetes, ischemia‐induced neuronal cell death, experimental autoimmune encephalomyelitis (EAE), multiple sclerosis (MS), inflammatory arthritis, cardiovascular and ocular disorders illustrate P35's utilization across diverse therapeutic areas and will certainly make it an attractive biomolecule for the discovery research. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Chaperone Activity of Bicyclic Nojirimycin Analogues for Gaucher Mutations in Comparison with N‐(n‐nonyl)Deoxynojirimycin
Authors: Luan Zhuo , Higaki Katsumi , Aguilar‐Moncayo Matilde , Ninomiya Haruaki , Ohno Kousaku , García‐Moreno M. Isabel , Ortiz Mellet Carmen , García Fernández José M. , Suzuki Yoshiyuki
Published: October 2009

Gaucher disease (GD), the most prevalent lysosomal storage disorder, is caused by mutations of lysosomal β‐glucosidase (acid β‐Glu, β‐glucocerebrosidase); these mutations result in protein misfolding. Some inhibitors of this enzyme, such as the iminosugar glucomimetic N‐(n‐nonyl)‐1‐deoxynojirimycin (NN‐DNJ), are known to bind to the active site and stabilize the proper folding for the catalytic form, acting as “chemical chaperones” that facilitate transport and maturation of acid β‐Glu. Recently, bicyclic nojirimycin (NJ) analogues with structure of sp2 iminosugars were found to behave as very selective, competitive inhibitors of the lysosomal β‐Glu. We have now evaluated the glycosidase inhibitory profile of a series of six compounds within this family, namely 5‐N,6‐O‐(N′‐octyliminomethylidene‐NJ (NOI‐NJ), the 6‐thio and 6‐amino‐6‐deoxy derivatives (6S‐NOI‐NJ and 6N‐NOI‐NJ) and the corresponding galactonojirimycin (GNJ) counterparts (NOI‐GNJ, 6S‐NOI‐GNJ and 6N‐NOI‐GNJ), against commercial as well as lysosomal glycosidases. The chaperone effects of four selected candidates (NOI‐NJ, 6S‐NOI‐NJ, 6N‐NOI‐NJ, and 6S‐NOI‐GNJ) were further evaluated in GD fibroblasts with various acid β‐Glu mutations. The compounds showed enzyme enhancement on human fibroblasts with N188S, G202R, F213I or N370S mutations. The chaperone effects of the sp2 iminosugar were generally stronger than those observed for NN‐DNJ; this suggests that these compounds are promising candidates for clinical treatment of GD patients with a broad range of β‐Glu mutations, especially for neuronopathic forms of Gaucher disease.
Open Sesame Technique for chronic total occlusion
Authors: Saito Shigeru
Published: October 2009

Angioplasty for chronic total occlusion (CTO) of the coronary artery is still technically challenging. New techniques to improve the success rate are still required. The inability to penetrate guidewires into the CTO lesion through the proximal cap is one of the most difficult situations. When any guidewire cannot penetrate into the CTO lesion, and if the lesion has both a hard proximal cap and a side branch ramifying at the proximal end of the lesion, the insertion of stiff guidewires and/or balloon inflation in the side branch may induce a geometrical shift of the hard plaque. This in turn enables the entry of a guidewire into the CTO lesion. This procedure has been termed the “Open Sesame Technique.” © 2009 Wiley‐Liss, Inc.
The Effect of Bromide Pretreatment on the Performance of Supported Au–Pd Catalysts for the Direct Synthesis of Hydrogen Peroxide
Authors: Ntainjua N. Edwin , Piccinini Marco , Pritchard James C. , He Qian , Edwards Jennifer K. , Carley Albert F. , Moulijn Jacob A. , Kiely Christopher J. , Hutchings Graham J.
Published: October 2009

The effect of pretreating Au–Pd catalysts on MgO and C supports with aqueous bromide solution, prior to using them for the direct synthesis of hydrogen peroxide, has been investigated. These two supports were selected since the parent materials exhibit contrasting microstructures and activities. The carbon‐supported catalysts comprise homogeneous Au–Pd alloy nanoparticles, which give high activity, whereas the MgO‐supported catalyst has Au–Pd alloys with a Pd‐rich surface and a Au‐rich core, which result in lower activity. Pretreatment of these catalysts with bromide was found to enhance H2O2 productivity and the degree of enhancement was largely dependent on the nature of the Au–Pd nanoparticles. Whereas bromide pretreatment significantly enhanced H2O2 productivity over the MgO‐based catalysts, the carbon‐based catalyst only showed a subtle promotional effect. Very low loadings of bromide (0.00034–0.044 wt %) were required to yield a significant positive effect. Higher bromide loadings (0.5–8.3 wt %) proved deleterious. The promotional effect has been correlated to selective poisoning of sites responsible for H2O2 hydrogenation and decomposition. In view of the limited effect of bromide pretreatment on the yield of H2O2 coupled with the effective performance of the carbon supported Au‐Pd catalysts in the absence of halides, for practical processes the addition of halides is not considered advisable with this catalyst system.
Structural Diversity of Infinite 3d–4f Heterometallic Cluster Compounds Driven by Various Lanthanide Radii
Authors: Xiang Shengchang , Hu Shengmin , Sheng Tianlu , Chen Jianshan , Wu Xintao
Published: October 2009

The syntheses, structures, and characterization of six Ln3+–Cu2+–glycine (Hgly) coordination polymers are described in this paper. They represent three types of structures. Type I (Ln=La (1), Pr (2), and Sm (3)) is a 1D catenarian polymer comprising [Ln2] nodes bridged by four cis‐Cu(gly)2 linkers. Type II (Ln=Eu (4) and Dy (5)) is a 2D open framework with a 44‐net, composed of novel [Ln6Cu22] cluster nodes linked by trans‐Cu(gly)2 linkers. Furthermore, the inner structures of the [Ln6Cu22] nodes, and the connection mode between the nodes and linkers are slightly different for 4 and 5. Type III (Ln=Er (6)) is a 3D open framework with a novel 36⋅418⋅53⋅6 topology, made up of [Er6Cu24] cluster nodes and trans‐Cu(gly)2 linkers. The rich variety of the resulting structures owes itself mainly to the interselection between the dynamic control of metalloligands and cationic components. A transition from frequency dependence to frequency independence is observed in the field‐induced magnetization lag for 1–3. The frequency dependence at low temperatures may come from the antiferromagnetic CuCu interaction through the [Ln2] nodes, whereas the frequency independence may be due to the disappearance of the antiferromagnetic CuCu interaction at high temperatures.
Expression of transient receptor potential ankyrin 1 (TRPA1) in the rat trigeminal sensory afferents and spinal dorsal horn
Authors: Kim Yun Sook , Son Jae Youn , Kim Tae Heon , Paik Sang Kyoo , Dai Yi , Noguchi Koichi , Ahn Dong Kuk , Bae Yong Chul
Published: October 2009

Transient receptor potential ankyrin 1 (TRPA1), responding to noxious cold and pungent compounds, is implicated in the mediation of nociception, but little is known about the processing of the TRPA1‐mediated nociceptive information within the trigeminal sensory nuclei (TSN) and the spinal dorsal horn (DH). To address this issue, we characterized the TRPA1‐positive (+) neurons in the trigeminal ganglion (TG) and investigated the distribution of TRPA1+ afferent fibers and their synaptic connectivity within the rat TSN and DH by using light and electron microscopic immunohistochemistry. In the TG, TRPA1 was expressed in unmyelinated and small myelinated axons and also occasionally in large myelinated axons. Many TRPA1+ neurons costained for the marker for peptidergic neurons substance P (26.8%) or the marker for nonpeptidergic neurons IB4 (44.5%). In the CNS, small numbers of axons and terminals were immunopositive for TRPA1 throughout the rostral TSN, in contrast to the dense network of positive fibers and terminals in the superficial laminae of the trigeminal caudal nucleus (Vc) and DH. The TRPA1+ terminals contained clear round vesicles, were presynaptic to one or two dendrites, and rarely participated in axoaxonic contacts, suggesting involvement in relatively simple synaptic circuitry with a small degree of synaptic divergence and little presynaptic modulation. Immunoreactivity for TRPA1 was also occasionally observed in postsynaptic dendrites. These results suggest that TRPA1‐dependent orofacial and spinal nociceptive input is processed mainly in the superficial laminae of the Vc and DH in a specific manner and may be processed differently between the rostral TSN and Vc. J. Comp. Neurol. 518:687–698, 2010. © 2009 Wiley‐Liss, Inc.
Regional and subcellular distribution of HDAC4 in mouse brain
Authors: Darcy Michael J. , Calvin Kate , Cavnar Katie , Ouimet Charles C.
Published: October 2009

Histone deacetylases (HDACs) are part of a system that links epigenetic control of gene expression to a variety of environmental stimuli. Some HDACs, including HDAC4, shuttle between the cytoplasm and nucleus in response to physiological cues such as calcium signaling. HDAC4 mRNA is enriched in the brain, but the regional and subcellular protein expression pattern of HDAC4 is not known. Here we show that HDAC4 is more highly expressed in some brain regions than in others. HDAC4 is present in the perikaryial cytoplasm of most neurons but its nuclear localization is variable. In some areas, such as the dentate gyrus, nuclear expression is not detectable, whereas in other areas some neuronal nuclei contain HDAC4 immunoreactivity whereas others do not. In the cytoplasm, HDAC4 immunoreactivity is punctate. Some of these puncta are present in dendritic spines where the strongest immunoreactivity is associated with the postsynaptic density. These data demonstrate that the regional and subcellular distribution of HDAC4 is heterogeneous and raise the possibilities that HDAC4 acts on nonhistone substrates in dendritic spines or that it shuttles between spine and nucleus to coordinate synaptic activity with gene expression. J. Comp. Neurol. 518:722–740, 2010. © 2009 Wiley‐Liss, Inc.
Ultrafast Relaxation Dynamics of the Excited States of 1‐Amino‐ and 1‐(N,N‐Dimethylamino)‐fluoren‐9‐ones
Authors: Varne Mahendra , Samant Vaishali , Mondal Jahur A. , Nayak Sandip K. , Ghosh Hirendra N. , Palit Dipak K.
Published: October 2009

The dynamics of the excited states of 1‐aminofluoren‐9‐one (1AF) and 1‐(N,N‐dimethylamino)‐fluoren‐9‐one (1DMAF) are investigated by using steady‐state absorption and fluorescence as well as subpicosecond time‐resolved absorption spectroscopic techniques. Following photoexcitation of 1AF, which exists in the intramolecular hydrogen‐bonded form in aprotic solvents, the excited‐state intramolecular proton‐transfer reaction is the only relaxation process observed in the excited singlet (S1) state. However, in protic solvents, the intramolecular hydrogen bond is disrupted in the excited state and an intermolecular hydrogen bond is formed with the solvent leading to reorganization of the hydrogen‐bond network structure of the solvent. The latter takes place in the timescale of the process of solvation dynamics. In the case of 1DMAF, the main relaxation pathway for the locally excited singlet, S1(LE), or S1(ICT) state is the configurational relaxation, via nearly barrierless twisting of the dimethylamino group to form the twisted intramolecular charge‐transfer, S1(TICT), state. A crossing between the excited‐state and ground‐state potential energy curves is responsible for the fast, radiationless deactivation and nonemissive character of the S1(TICT) state in polar solvents, both aprotic and protic. However, in viscous but strong hydrogen‐bond‐donating solvents, such as ethylene glycol and glycerol, crossing between the potential energy surfaces for the ground electronic state and the hydrogen‐bonded complex formed between the S1(TICT) state and the solvent is possibly avoided and the hydrogen‐bonded complex is weakly emissive.
Biomimetic F‐Actin Cortex Models
Authors: Haraszti Tamás , Clemen Anabel E.‐M. , Spatz Joachim P.
Published: October 2009

Since its first production from muscle tissue more than 65 years ago, our knowledge about actin has come a long way. While at the beginning it was identified as a muscle protein, nowadays actin is considered as one of the most important components of the cytoskeleton, playing a crucial role in cell motility, adhesion, morphology and intracellular transport processes. In vitro models have been constructed for about 20 years to gain better insight into the chemophysical and biomechanical properties of actin networks by being able to reduce and tune its complexity. The complexity of these models ranges from single actin filaments (F‐actin) in interaction with actin‐associated molecules and proteins, F‐actin network gels to F‐actin loaded vesicles to freely suspended F‐actin networks in microfluidic environments. This review summarizes the development of F‐actin network models and highlights their applicability towards step‐by‐step construction of complex cortex mimicking systems.
Rapid Prediction of the Hydrogen Bond Cooperativity inN‐methylacetamide Chains
Authors: Jiang Xiao‐Nan , Wang Chang‐Sheng
Published: October 2009

A method is proposed to rapidly predict the hydrogen bond cooperativity inN‐methylacetamide chains. The parameters needed are obtained from the fittings to the hydrogen bonding energies in the formamide chains containing 2 to 8 monomeric units. The scheme is then used to calculate the individual hydrogen bonding energies inN‐methylacetamide chains containing 2 to 7 monomeric units. The cooperativity predicted is in good agreement with those obtained from MP2/6‐31+G** calculations by including the BSSE correction. Our scheme is further employed to predict the individual hydrogen bonding energies in largerN‐methylacetamide chains containing up to 200 monomericN‐methylacetamide units, to which the MP2 method cannot be applied. Based on our scheme, a cooperative effect of over 170 % of the dimer hydrogen bonding energy in longN‐methylacetamide chains is predicted. The method is also applied to heterogeneous chains containing formamide, acetamide,N‐methylformamide, andN‐methylacetamide. The individual hydrogen bonding energies in these heterogeneous chains are also in good agreement with those obtained from MP2 calculations with the BSSE correction, further demonstrating that our method is reasonable.
Probing Biomembrane Dynamics by Dual‐Wavelength Reflection Interference Contrast Microscopy
Authors: Monzel Cornelia , Fenz Susanne F. , Merkel Rudolf , Sengupta Kheya
Published: October 2009

We present an improved analysis of reflection interference contrast microscopy (RICM) images, recorded to investigate model membrane systems that mimic cell adhesion. The model systems were giant unilamellar vesicles (GUV) adhering via specific ligand–receptor interactions to supported lipid bilayers (SLB) or to patterns of receptors. Conventional RICM and dual‐wavelength RICM (DW–RICM) were applied to measure absolute optical distances between the biomembranes and planar substrates. We developed algorithms for a straightforward implementation of an automated, time‐resolved reconstruction of the membrane conformations from RICM/DW–RICM images, taking into account all the interfaces in the system and blurring of the data due to camera noise. Finally, we demonstrate the validity and usefulness of this new approach by analyzing the topography and fluctuations of a bound membrane in the steady state and its dynamic adaptation to osmotic pressure changes. These measurements clearly show that macroscopic membrane flow through tightly adhered area is possible in our system.
NBDT (3‐(N‐(7‐nitrobenz‐2‐oxa‐1,3‐diazol‐4‐yl)amino)‐3‐toluene)—A novel fluorescent dye for studying mechanisms of toluene uptake into vital bacteria
Authors: Sträuber H. , Hübschmann T. , Jehmlich N. , Schmidt F. , von Bergen M. , Harms H. , Müller S.
Published: October 2009

Uptake of small hydrophobic substances such as toluene into bacteria is widely assumed to occur by passive diffusion. Some toluene degrading bacteria, however, are described to contain uptake systems which may be involved in the transport of this compound. In this study, a fluorescently labeled toluene analogue dye (3‐(N‐(7‐nitrobenz‐2‐oxa‐1,3‐diazol‐4‐yl)amino)‐3‐toluene; NBDT), flow cytometry, and shot gun proteome analysis were used to follow toluene uptake into bacteria in more detail. The new dye has excitation peaks at 444 and 475 nm and an emission peak at 537 nm. The toluene‐degraders P. putida mt‐2 and P. putida F1 as well as P. putida KT2440 and E. coli K12 as negative controls were included. To enable quantification of NBDT uptake, carbonyl cyanide 3‐chlorophenylhydrazone (CCCP) was added to inactivate NBDT efflux pumps. The porin inhibitor cadaverine was added to study the porin‐mediated influx of toluene. Cadaverine reduced NBDT uptake by toluene‐grown P. putida mt‐2 and F1 by 25% and 42%, respectively, thus revealing an involvement and possibly a regulatory function of porins in the uptake of the toxic substrate toluene. Shot gun proteome measurements gave evidence for the presence of toluene transporting porins in P. putida mt‐2 grown on toluene but not when grown on glucose. © 2009 International Society for Advancement of Cytometry
Adaptive smooth multicast protocol for multimedia transmission: Implementation details and performance evaluation
Authors: Bouras Christos , Gkamas Apostolos , Kioumourtzis Georgios
Published: October 2009

In this paper we propose a new single‐rate multicast congestion control scheme named Adaptive Smooth Multicast Protocol (ASMP), for multimedia transmission over best‐effort networks. The smoothness lays in the calculation and adaptation of the transmission rate, which is based on dynamic estimations of protocols' parameters and dynamic adjustment of the ‘smoothness factor’, as well. ASMP key attributes are: (a) TCP‐friendly behavior, (b) adaptive scalability to large sets of receivers, (c) high bandwidth utilization, and finally (d) smooth transmission rates, which are suitable for multimedia applications. We evaluate the performance of ASMP and investigate its behavior under various network conditions through extensive simulations conducted with the network simulator software (ns2). Simulation results show that ASMP can be regarded as a serious competitor of TFMCC and PGMCC. In many cases, ASMP outperforms TFMCC in terms of TCP‐friendliness and smooth transmission rates, while PGMCC presents lower scalability than ASMP. We have implemented ASMP on top of RTP/RTCP protocols in ns2 by adding all the RTP/RTCP protocol's attributes that are defined in RFC 3550 and related to quality of service metrics. Copyright © 2009 John Wiley & Sons, Ltd.
New hemocyte‐specific enhancer‐reporter transgenes for the analysis of hematopoiesis in Drosophila
Authors: Tokusumi Tsuyoshi , Shoue Douglas A. , Tokusumi Yumiko , Stoller Jessica R. , Schulz Robert A.
Published: October 2009

Based on environmental challenges or altered genetic composition, Drosophila larvae can produce up to three types of blood cells that express genetic programs essential for their distinct functions. Using transcriptional enhancers for genes expressed exclusively in plasmatocytes, crystal cells, or lamellocytes, several new hemocyte‐specific enhancer‐reporter transgenes were generated to facilitate the analysis of Drosophila hematopoiesis. This approach took advantage of fluorescent variants of insulated P‐element reporter vectors for multilabeling cell analyses; two additional color variants were generated in these studies. These vectors were successfully used to produce transgenic fly lines that label specific hemocyte lineages with separate colors. Combining three transgene reporters allowed for the unambiguous identification of plasmatocytes, crystal cells, and lamellocytes within a complex hemocyte population. While this work focused on the hematopoietic process, these new vectors can be used to mark multiple cell types or trace complex cell lineages during any chosen aspect of Drosophila development. genesis 47:771–774, 2009. © 2009 Wiley‐Liss, Inc.
Dual fluorescent protein reporters for studying cell behaviors in vivo
Authors: Stewart M. David , Jang Chuan‐Wei , Hong Nicholas W. , Austin Anthony P. , Behringer Richard R.
Published: October 2009

HeLa cells transfected with plasmids expressing dual fluorescent protein reporters with cherry, green, and cyan fluorscent proteins. Histone 2B fusions localize fluorescent proteins to the nucleus, while fluorescent proteins fused to glycosylphosphatidylinositol anchor signal sequence localizes to plasma membranes. These dual fluorescent reporters label nuclear and plasma membranes of live cells to follow their behaviors in developing embryos. See the paper by Stewart et al. in this issue.
Critical role for the immunoproteasome subunit LMP7 in the resistance of mice to Toxoplasma gondii infection
Authors: Tu Liping , Moriya Chikako , Imai Takashi , Ishida Hidekazu , Tetsutani Kohhei , Duan Xuefeng , Murata Shigeo , Tanaka Keiji , Shimokawa Chikako , Hisaeda Hajime , Himeno Kunisuke
Published: October 2009

Proteasome‐mediated proteolysis is responsible for the generation of immunogenic epitopes presented by MHC class I molecules, which activate antigen‐specific CD8+ T cells. Immunoproteasomes, defined by the presence of the three catalytic subunits LMP2, MECL‐1, and LMP7, have been hypothesized to optimize MHC class I antigen processing. In this study, we demonstrate that the infection of mice with a protozoan parasite, Toxoplasma gondii, induced the expression of LMP7 mRNA in APC and increased the capacity of APC to induce the production of IFN‐γ by antigen‐specific CD8+ T cells. In vitro infection of a DC cell line with T. gondii also induced the expression of LMP7 and resulted in enhanced proteasome proteolytic activity. Finally, mice lacking LMP7 were highly susceptible to infection with T. gondii and showed a reduced number of functional CD8+ T cells. These results demonstrate that proteasomes containing LMP7 play an indispensable role in the survival of mice infected with T. gondii, presumably due to the efficient generation of CTL epitopes required for the functional development of CD8+ T cells.
Reassessing the role of HLA‐DRB3 T‐cell responses: Evidence for significant expression and complementary antigen presentation
Authors: Faner Rosa , James Eddie , Huston Laurie , Pujol‐Borrel Ricardo , Kwok William W. , Juan Manel
Published: October 2009

In humans, several HLA‐DRB loci (DRB1/3/4/5) encode diverse β‐chains that pair with α‐chains to form DR molecules on the surface of APC. While DRB1 and DRB5 have been extensively studied, the role of DRB3/4 products of DR52/DR53 haplotypes has been largely neglected. To clarify the relative expression of DRB3, we quantified DRB3 mRNA levels in comparison with DRB1 mRNA from the same haplotype in both B cells and monocytes, observing quantitatively significant DRB3 synthesis. In CD19+ cells, DRB1*03/11/13 was 3.5‐fold more abundant than DRB3, but in CD14+ this difference was only two‐fold. Monocytes also had lower overall levels of DR mRNA compared with B cells, which was confirmed by cell surface staining of DRB1 and DRB3. To evaluate the functional role of DRB3, tetramer‐guided epitope mapping was used to detect T cells against tetanus toxin and several influenza antigens presented by DRB3*0101/0202 or DRB1*03/11/13. None of the epitopes discovered were shared among any of the DR molecules. Quantitative assessment of DRB3‐tetanus toxin specific T cells revealed that they are present at similar frequencies as those observed for DRB1. These results suggest that DRB3 plays a significant role in antigen presentation with different epitopic preferences to DRB1. Therefore, DRB3, like DRB5, serves to extend and complement the peptide repertoire of DRB1 in antigen presentation.
Butyrate mediates nucleotide‐binding and oligomerisation domain (NOD) 2‐dependent mucosal immune responses against peptidoglycan
Authors: Leung Chung‐Hang , Lam Wing , Ma Dik‐Lung , Gullen Elizabeth A. , Cheng Yung‐Chi
Published: October 2009

The interaction between digestive tract microbiological flora and food has an important influence on human health. Butyrate is produced during the fermentation of dietary fibres by intestinal bacteria and plays an important role in the regulation of mucosal immunity. In this report, we studied the impact of butyrate on the defence mechanism against the bacterial membrane component peptidoglycan (PGN). Butyrate was found to enhance PGN‐mediated IL‐8 and GRO‐α production. The expression of these chemokines required the activation of NF‐κB and was dependent on the concentrations of butyrate and PGN. Butyrate was found to up‐regulate nucleotide‐binding and oligomerisation domain (NOD) 2, but not NOD1 or TLR2. NOD2 up‐regulation was mediated by an increase in histone acetylation in the Nod2 promoter region, leading to enhanced PGN‐induced IL‐8 and GRO‐α secretion. Knockdown of NOD2 and TLR2 by siRNA significantly reduced PGN‐mediated chemokine production, suggesting that both NOD2 and TLR2 are required for maximal response. Our findings provide a better understanding of the mechanism by which butyrate regulates mucosal immunity for normal intestinal function. Based on the results of this study, we infer that dietary fibres can impact inflammatory bowel diseases.
Chemokine receptor Ccr5 deficiency induces alternative macrophage activation and improves long‐term renal allograft outcome
Authors: Dehmel Stefan , Wang Shijun , Schmidt Claudia , Kiss Eva , Loewe Robert P. , Chilla Silvia , Schlöndorff Detlef , Gröne Hermann‐Josef , Luckow Bruno
Published: October 2009

The chemokine (C‐C motif) receptor 5 (CCR5) has been implicated in experimental and clinical allograft rejection. To dissect the function of CCR5 in acute and chronic renal allograft rejection, bilaterally nephrectomized WT and Ccr5−/− C57BL/6 mice were used as recipients of WT BALB/c renal allografts and analyzed 7 and 42 days after transplantation. Lesion scores (glomerular damage, vascular rejection, tubulointerstitial inflammation) and numbers of CD4+, CD8+, CD11c+ and alpha smooth muscle actin (αSMA)+ cells were reduced in allografts from Ccr5−/− recipients during the chronic phase. Increasing creatinine levels indicated deterioration of allograft function over time. While mRNA expression of Th1‐associated markers decreased between 7 and 42 days, Th2‐associated markers increased. Markers for alternatively activated macrophages (arginase 1, chitinase 3‐like 3, resistin‐like α, mannose receptor, C type 1), were strongly upregulated (mRNA and/or protein level) only in allografts from Ccr5−/− recipients at 42 days. Ccr5 deficiency shifted intragraft immune responses during the chronic phase towards the Th2 type and led to accumulation of alternatively activated macrophages. Additionally, splenocytes from unchallenged Ccr5−/− mice showed significantly increased arginase 1 and mannose receptor 1 mRNA levels, suggesting constitutive alternative activation of splenic macrophages. We conclude that Ccr5 deficiency favors alternative macrophage activation. This finding may be relevant for other inflammatory diseases that involve macrophage activation and may also influence future therapeutic strategies targeting CCR5.
HIV gag protein is efficiently cross‐presented when targeted with an antibody towards the DEC‐205 receptor in Flt3 ligand‐mobilized murine DC
Authors: Bozzacco Leonia , Trumpfheller Christine , Huang Yaoxing , Longhi Maria Paula , Shimeliovich Irina , Schauer Joseph D. , Park Chae Gyu , Steinman Ralph M.
Published: October 2009

DC present exogenous proteins to MHC class I‐restricted CD8+ T cells. This function does not require endogenous antigen synthesis within DC, providing the potential to elicit CD8+ T‐cell responses to immune complexes, inactivated microbes, dying cells, and proteins such as OVA. In mice, the CD8+ or DEC‐205+ DC are specialized for cross‐presentation, and this subset can be increased 10‐fold in numbers following Fms‐like tyrosine kinase 3 ligand (Flt3L) treatment in vivo. Therefore, we studied cross‐presentation by abundant Flt3L DC using HIV gag protein. When enriched by positive selection with anti‐CD11c beads, cells from Flt3L mice are not only more abundant but are also more highly enriched in CD11chigh DC, particularly the DEC‐205+ subset. DC cross‐present HIV gag to primed CD8+ T cells, but when the antigen is delivered within an antibody to DEC‐205 receptor, cross‐presentation becomes 100‐fold more efficient than non‐targeted antigen. This finding requires gag to be engineered into anti‐DEC antibody, not just mixed with antibody. Flt3L DC are a valuable tool to study cross‐presentation, since their use overcomes the obstacle posed by the low number of cross‐presenting DC in the steady state. These findings support future experiments to use Flt3L to enhance presentation of DC‐targeted vaccines.
The antimicrobial activity of CCL28 is dependent on C‐terminal positively‐charged amino acids
Authors: Liu Bin , Wilson Eric
Published: October 2009

Several chemokines have been shown to act as antimicrobial proteins, suggesting a direct contribution to innate immune protection. Based on the study of defensins and other antimicrobial peptides, it has been proposed that cationic amino acids in these proteins play a key role in their antimicrobial activity. The primary structure requirements necessary for the antimicrobial activity of chemokines, however, have not yet been elucidated. Using mouse CCL28, we have identified a C‐terminal region of highly‐charged amino acids (RKDRK) that is essential to the antimicrobial activity of the murine chemokine. Additionally, other positively‐charged amino acids in the C‐terminus of the protein contribute to the observed antimicrobial effect. Charge reversal and deletion mutations support our hypothesis that C‐terminal positively‐charged amino acids are essential for the antimicrobial activity of CCL28. Results also demonstrate that although the C‐terminal region of the chemokine is essential, it is not sufficient for full antimicrobial activity of CCL28.
Magnesium(II) Complexes of the dpp‐BIAN Radical‐Anion: Synthesis, Molecular Structure, and Catalytic Activity in Lactide Polymerization
Authors: Fedushkin Igor L. , Morozov Alexander G. , Chudakova Valentina A. , Fukin Georgy K. , Cherkasov Vladimir K.
Published: October 2009

Reaction of (dpp‐BIAN)Mg(THF)3 (1) {dpp‐BIAN = 1,2‐bis[(2,6‐diisopropylphenyl)imino]acenaphthene} with one molar equivalent of 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) proceeds with oxidation of the dpp‐BIAN dianion in 1 to the radical‐anion and affords the (dpp‐BIAN)Mg(TEMPO)(thf) (2) complex. The reaction of dpp‐BIAN with an excess amount of magnesium and 0.5 molar equivalents of I2 in Et2O gives (dpp‐BIAN)MgI(Et2O)n, which then reacts in situ with (Me3Si)2NK to produce (dpp‐BIAN)Mg[N(SiMe3)2](Et2O) (3). Solvent‐free magnesium amide (dpp‐BIAN)Mg[N(SiMe3)2] (4) was synthesized by treating equimolar amounts of MgI2, dpp‐BIAN, and sodium in toluene at reflux followed by treatment with (Me3Si)2NK. Deprotonation of diphenylacetonitrile with [(dpp‐BIAN)Mg(μ‐Me)]2 (5) produces keteniminate complex (dpp‐BIAN)Mg(N=C=CPh2)(Et2O) (6). Complexes 2–4 and 6 were characterized by ESR and IR spectroscopy; their molecular structures were determined by single‐crystal X‐ray analysis. Compounds 1–3 catalyze the ring‐opening polymerization of L‐ and rac‐lactides to give high molecular weight isotactic and stereoblock polylactides correspondingly.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
An Unprecedented Trinuclear Dawson Sandwich Complex with Internal Lacuna: Synthesis and 31P NMR Spectroscopic Analysis of the Symmetrical [NaNi3(H2O)2(P2W15O56)2]17– and [CoNi3(H2O)2(P2W15O56)2]16– Anions
Authors: Schaming Delphine , Canny Jacqueline , Boubekeur Kamal , Thouvenot René , Ruhlmann Laurent
Published: October 2009

The tri‐nickel Dawson sandwich complex [NaNi3(H2O)2(P2W15O56)2]17– has been obtained from [P2W15O56]12– and Ni2+. The X‐ray crystal structure analysis is reported. This complex presents an unprecedented structure with the three transition metal ions in two external and one internal positions. Addition of 1 equiv. of Co2+ in the solution of {NaNi3P4W30} leads to the formation of the “saturated” mixed‐metal sandwich complex [CoNi3(H2O)2(P2W15O56)2]16–, which is characterized by microanalysis, IR and 31P NMR spectroscopy. The electrochemical behaviour of {NaNi3P4W30} and {CoNi3P4W30} are also reported.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)