bluuebunny/crossref_metadata_2025 huggingface dataset:
Ice Recrystallization Inhibition and Molecular Recognition of Ice Faces by Poly(vinyl alcohol)
Authors: Budke Carsten , Koop Thomas
Published: November 2006

The effects of poly(vinyl alcohol) (PVA) on the Ostwald ripening of polycrystalline ice samples are studied. At −6 °C, ice recrystallization in sucrose solutions is inhibited at PVA concentrations down to 0.005 mg mL−1, with a recrystallization inhibition constant of 48.9 mL mg−1. Ice growth‐habit experiments reveal molecular recognition of the arrangement of water molecules in the ice by PVA molecules, and indicate that PVA molecules adsorb to the primary and secondary prism faces of hexagonal ice, Ih. Based on these observations, together with an analysis of the O‐atom pattern in ice and the conformation of OH groups in PVA, an adsorption model is proposed. We suggest that PVA segments adsorb to the primary and secondary prism faces of ice parallel to the c axis with a linear misfit parameter of only 2.7 %, most likely via multiple hydrogen bonds. The proposed adsorption mechanism is discussed in the light of recent thermal hysteresis and scanning tunneling microscopy experiments.
Adaptive quality of service‐based routing approaches: development of neuro‐dynamic state‐dependent reinforcement learning algorithms
Authors: Mellouk Abdelhamid , Hoceïni Saïd , Amirat Yacine
Published: November 2006

In this paper, we propose two adaptive routing algorithms based on reinforcement learning. In the first algorithm, we have used a neural network to approximate the reinforcement signal, allowing the learner to take into account various parameters such as local queue size, for distance estimation. Moreover, each router uses an online learning module to optimize the path in terms of average packet delivery time, by taking into account the waiting queue states of neighbouring routers. In the second algorithm, the exploration of paths is limited to N‐best non‐loop paths in terms of hops number (number of routers in a path), leading to a substantial reduction of convergence time. The performances of the proposed algorithms are evaluated experimentally with OPNET simulator for different levels of traffic's load and compared with standard shortest‐path and Q‐routing algorithms. Our approach proves superior to classical algorithms and is able to route efficiently even when the network load varies in an irregular manner. We also tested our approach on a large network topology to proof its scalability and adaptability. Copyright © 2006 John Wiley & Sons, Ltd.
Toward the discovery of small molecule PTP1B inhibitors for the treatment of metabolic diseases
Authors: Nichols Andrew J. , Mashal Robert D. , Balkan Bork
Published: November 2006

PTP1B is a protein tyrosine phosphatase involved in insulin and leptin signaling and is a primary mechanism for down‐regulating both the insulin and leptin receptor signaling pathways. Animals deficient in PTP1B have improved glucose regulation and lipid profiles and are resistant to weight gain when treated with a high fat diet. Thus, PTP1B inhibitors are expected to be useful in the treatment of type 2 diabetes, obesity, and the metabolic syndrome. Progress toward the design of potent and orally active PTP1B inhibitors has been hindered by the highly charged nature of the tyrosine phosphate mimetics used to date. Recent progress in the design of more drug‐like molecules holds promise for the eventual discovery and development of clinically useful PTP1B inhibitors. Drug Dev. Res. 67:559–566, 2006. © 2006 Wiley‐Liss, Inc.
Clinical significance of postprandial hyperglycemia
Authors: Gerich John E. , Woerle Hans J.
Published: November 2006

This review will summarize evidence that postprandial hyperglycemia (1) is an independent risk factor for cardiovascular disease; (2) increases earlier and faster than fasting plasma glucose levels; and (3) contributes more to HbA1c levels than fasting hyperglycemia when HbA1c levels approach target values and, therefore, is the rate‐limiting factor for achieving optimal glycemic control. Finally, treatment recommendations will be presented. Drug Dev. Res. 67:587–590, 2006. © 2006 Wiley‐Liss, Inc.
Hypertension, diabetes, insulin resistance, and postprandial hyperglycemia
Authors: Bell David S.H.
Published: November 2006

Diabetes is associated with an increased risk of cardiac events and congestive heart failure. The improvement in outcomes for mortality in non‐diabetic subjects over the last decade has not been matched in the diabetic patient. This may be due to a failure to intensify therapy in the diabetic patient. An essential part of this intensification includes treatment of hypertension. Lower blood pressure levels in the diabetic patient have been shown to be associated with a lower rate of cardiovascular events. Both hyperglycemia and hyperinsulinemia due to insulin resistance are responsible for the increased prevalence of hypertension in the type 2 diabetic subject. Even non‐diabetic insulin‐resistant hypertensive subjects have higher post‐prandial glucoses. The higher the post‐prandial glucose, the greater is the risk of atherosclerosis, and lowering of post‐prandial glucoses results in less cardiac events. Drug Dev. Res. 67:595–596, 2006. © 2006 Wiley‐Liss, Inc.
Effect of heat shock protein peptide DiaPep277 on ß‐cell function in paediatric and adult patients with recent‐onset diabetes mellitus type 1: two prospective, randomized, double‐blind phase II trials
Authors: Schloot Nanette C. , Meierhoff Guido , Lengyel Csaba , Vándorfi Gyözö , Takács József , Pánczél Pál , Barkai László , Madácsy László , Oroszlán Tamás , Kovács Peter , Sütö Gábor , Battelino Tadej , Hosszufalusi Nora , Jermendy György
Published: November 2006

Background

Aim of this trial was to test whether heat shock protein peptide DiaPep277 treatment in adult and paediatric patients with recent‐onset type 1 diabetes (T1D) is safe and whether it can preserve endogenous insulin production.

Methods

Two studies were performed in a prospective, multicentre, double‐blind, placebo‐controlled trial. Fifty adult (study p520, aged 16–44 years) and 49 paediatric patients (study p521, 4–15 years) with recent‐onset T1D were treated subcutaneously at four different time points with 0.2 mg or 1.0 mg DiaPep277 versus placebo and followed for 18 months. Adult patients were treated with 0.2 mg, 1.0 mg or 2.5 mg DiaPep277 versus placebo. Stimulated C‐peptide served as readout for functional ß‐cell‐mass.

Results

DiaPep277‐treatment was not associated with severe side effects. No differences were found in placebo and DiaPep277 treated groups. In adults, a modest trend towards better maintenance of ß‐cell function was observed in the 0.2 mg and 1.0 mg group, while there was significant loss of stimulated C‐peptide in the placebo and 2.5 mg group. Paediatric patients with low HLA risk showed stable C‐peptide levels until 13 months upon treatment with 1 mg DiaPep277. Despite similar stimulated C‐peptide levels at baseline, children exhibited a more pronounced loss of ß‐cell function over 18 months than adults (p = 0.0003).

Conclusion

Administration of DiaPep277 seems safe and may have beneficial effects on C‐peptide levels over time in some patients with T1D, but this finding was not accompanied by reduced HbA1c or insulin requirement. Studies with more patients and longer follow‐up are needed to further study the effect of DiaPep277. Copyright © 2007 John Wiley & Sons, Ltd.
Pancreatin therapy in patients with insulin‐treated diabetes mellitus and exocrine pancreatic insufficiency according to low fecal elastase 1 concentrations. Results of a prospective multi‐centre trial
Authors: Ewald Nils , Bretzel Reinhard G , Fantus Ivan G , Hollenhorst Manfred , Kloer Hans U , Hardt Philip D
Published: November 2006

Background

Recently, high prevalence of exocrine dysfunction in diabetic populations has been reported. Patients with fecal elastase 1 concentration (FEC) <100 µg/g have also been demonstrated to suffer from steatorrhea in about 60% of cases, indicating the need of pancreatic enzyme replacement therapy. Until now, there have only been a few reports on the use of enzyme replacement therapy in diabetic patients with exocrine pancreatic insufficiency. This investigation was designed to evaluate the impact of enzyme‐replacement therapy on glucose metabolism and diabetes treatment in a prospective study of insulin‐treated patients with diabetes mellitus.

Methods

A total of 546 patients with diabetes mellitus requiring insulin treatment were screened for exocrine dysfunction by FEC measurements. One hundred and fifteen patients (21.1%) had FEC <100 µg/g (normal >200 µg/g). Of these, 95 patients entered the study and 80 patients were randomized to receive either pancreatin (Creon®) (39 patients) or placebo (41 patients) in a double‐blind manner. Parameters of glucose metabolism, diabetes therapy and clinical symptoms were recorded in standardized protocols for 16 weeks.

Results

During the observation phase of 16 weeks, there were no significant differences between both groups concerning HbA1c, fasting glucose levels, 2‐h pp glucose levels, clinical parameters and safety parameters. A reduction in mild and moderate hypoglycemia was observed in the pancreatin group at the end of the study.

Conclusions

Pancreatin therapy can be used safely in patients with diabetes mellitus and exocrine dysfunction. Parameters of glucose metabolism were not improved by enzyme replacement therapy. Copyright © 2007 John Wiley & Sons, Ltd.
U‐500 insulin: why, when and how to use in clinical practice
Authors: Garg R. , Johnston V. , McNally P. G. , Davies M. J. , Lawrence I. G.
Published: November 2006

Some patients with type 2 diabetes mellitus (T2DM) have severe insulin resistance. Their insulin requirements are significantly greater. These patients need to take 2–3 injections at the same time to take the correct insulin dose or to redial the insulin pen. When daily insulin requirements are in excess of 300 units/day, the volume of the injected insulin becomes an issue. Large‐volume injection can cause discomfort and lead to poor concordance with treatment. Using high‐strength insulin e.g. U‐500 insulin can reduce the volume of the injected insulin. Despite publications of small case reports or case series, no universal guidelines exist on the use of U‐500 insulin. We discuss common sense approaches when considering the use of U‐500 insulin in clinical practice. Copyright © 2006 John Wiley & Sons, Ltd.
Targeted gene delivery to differentiated skeletal muscle: A tool to study dedifferentiation
Authors: Morrison Jamie I. , Lööf Sara , He Pingping , Aleström Peter , Collas Philippe , Simon András
Published: November 2006

Cellular dedifferentiation is required for functional regeneration in salamanders. Dedifferentiating multinucleate skeletal muscle gives rise to mononucleate cells during limb regeneration. Efficient methods and tools must be developed in order to understand the molecular cues underlying dedifferentiation. Here we describe a non‐viral method to express extra‐chromosomal DNA exclusively in terminally differentiated muscle without the need for cell purification steps. After cytoplasmic injection of various expression vectors into myotubes or myofibres, we detect long‐lasting mRNA and protein expression in up to 70% of the injected cells. The combination of the transfection protocol with live imaging allows a time‐ and cost‐effective screen of candidate genes in terminally differentiated muscle cells of both amphibian and mammalian origin. Developmental Dynamics 236:481–488, 2007. © 2006 Wiley‐Liss, Inc.
Traffic characteristics of Go‐Back‐N ARQ scheme with selective repeat in intra‐block and with limited retransmissions
Authors: Fujii Shumji , Kaneko Toyohisa , Hayashida Yukuo
Published: November 2006

Based on highly reliable data transmission, we previously proposed a Go‐Back‐N ARQ scheme with selective repeat in intra‐block, where the receiver returns the acknowledge signal in the unit of a block composed of multiple frames, with the aim of reducing the network traffic and the objective of effectively processing the frames. This paper considers the traffic characteristics when the number of block retransmissions in a Go‐Back‐N ARQ scheme with selective repeat in intra‐block is limited. In this scheme, blocks composed of multiple frames which contain information with some correlation as in images are transmitted. If the retransmission of a block reaches the preset limit, the receiver accepts that block even if erroneous frames are included, and the errors are processed as noise or distortion. Therefore, an upper bound can be set for the time elapsed from the start to the end of the block transmission. We theoretically analyze the system considered and derive the throughput, the average transmission delay of a block, and the average transmission delay with the condition of the number of transmissions. The traffic characteristics are investigated from numerical examples using analytical results. We show that the throughput performance and average transmission delay performance are improved by limiting the number of retransmissions. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(3): 64–73, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20311
A feeding method for small helical antennas
Authors: Hasebe Nozomu
Published: November 2006

A feeding method is proposed for small helical antennas with diameters of about 1/80 to 1/20 wavelength. The present feeding method consists of excitation of a helix with a total length of about 1/4 wavelength and with its lower edge grounded by an open‐ended center conductor oriented coaxially to the helix. In this paper, it is shown that matching with a 50‐Ω feed system can be accomplished even when the helical diameter is varied in the same feeding method. The gain and the bandwidth characteristics of the ground plane versus diameter are discussed. As an example, a gain of −7.2 dBd (with respect to the dipole antenna) on the ground plane is obtained when the helical diameter is 1/46 wavelength and the height is 1/56 wavelength. Like the monopole antenna, the main radiation pattern is omnidirectional vertical polarization in the horizontal plane and figure‐eight in the vertical plane. When this antenna is installed on a transmitter case, the gain is about −4 dBd. When installed on the transmitter case, the antenna radiates the orthogonal polarization component. The null of the main radiation pattern in the zenith direction can be compensated by this polarization. The radiation characteristics of the antenna are numerically calculated by the method of moments and are verified experimentally. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(3): 33–41, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20324
All‐in‐focus photo image creation by wavelet transforms
Authors: Shirai Keiichiro , Nomura Kazufumi , Ikehara Masaaki
Published: November 2006

In this paper, we describe a method for creating all‐in‐focus photographic images where all of the subjects are in focus as much as possible from partially in‐focus photographs with only its subject in focus when photographed by a camera with manual focus. Usually, the focusing range and the depth of field are wide, but become extremely narrow for nearby subjects. Consequently, it is difficult to photograph many subjects in focus in closeup photography. In this paper, we can combine the transform coefficients using wavelet transforms and easily create photographic images with natural focus but without noticeable seams. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(3): 57–66, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20236
Fractal video coding with the orthogonal transformation
Authors: Ohse Koji , Nakagawa Masahiro
Published: November 2006

Fractal coding, which is coding with the self‐similarity of the image as redundancy, has recently been studied extensively. In this paper, a method of fractal video coding is proposed in which the redundancy along the time axis is eliminated from a sequence of videos by the orthogonal transformation and then the results are rearranged according to the frequency components before fractal video coding. In comparison with the conventional fractal video coding, the average PSNR is improved with almost identical information content. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(3): 36–47, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20248
Adaptive DOA estimation using a database of eigenvectors
Authors: Mochida Eiji , Iiguni Youji
Published: November 2006

With the dramatic advances in mobile communication technologies, the problem of estimating the direction of arrival (DOA) of signals generated by several sources becomes even more important. High‐resolution estimation methods based on eigenvalue decomposition include the minimum‐norm method and the MUSIC method. Since the peak of the angular spectrum must be scanned over all directions, the computational effort is enormous. In this paper, a DOA estimation method using a database is proposed. In this method, a database is constructed in which the eigenvector corresponding to the minimum eigenvalue is the key and the DOA is the associated value. The DOA is estimated by seeking in the database the data with the key closest to the eigenvector obtained from the observation signals. In the proposed method, DOA estimation can be achieved by only a regional search of the database, and hence the process is extremely fast. Finally, the effectiveness of the proposed method is demonstrated by simulation. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(3): 48–56, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20251
Performance improvement of vector quantizer with reflection group for uniform distribution on hyperspace
Authors: Yamane Nobumoto , Morikawa Yoshitaka , Mae Tomohiro , Takemoto Yuji , Maki Shuichi
Published: November 2006

A two‐stage vector quantizer (kaleidoscope vector quantizer: KVQ) using multidimensional symmetry which has a reflection group is proposed as a high‐speed vector quantizer (VQ) for vectors following a uniform distribution on a hypersphere. The first‐stage VQ of this method is a lattice quantizer on a hypersphere based on a reflection group and plays a central role in achieving higher dimensions and higher rates. The last‐stage VQ is a full‐search vector quantizer and plays the roles of repartitioning and reforming the Voronoi regions and improving the quantization properties. In this method, the code vectors are assigned only inside the first‐stage Voronoi regions. In this paper, a unified‐region KVQ is proposed as a method for improving the quantization characteristic in the high dimensions of KVQ. This method also assigns the code vectors of the last‐stage VQ to the boundary surfaces of the Voronoi regions of the first‐stage VQ. By using this method, the multiple Voronoi regions in the first‐stage VQ are merged and repartitioned, and the degree of freedom in the code vector assignment is increased. Simulation tests were conducted on Gaussian vectors and showed that the quantization characteristics equivalent to the full‐search VQ were obtained in the range of 16 dimensions and a rate of about 2.5 bits/sample. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(3): 26–35, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20261
Improved particle swarm optimization and application to portfolio selection
Authors: Koshino Makoto , Murata Hiroaki , Kimura Haruhiko
Published: November 2006

Particle swarm optimization (PSO) is a population‐based stochastic optimization technique, inspired by the social behavior of birds (flocking) or fish (schooling), which is applied to various problems in the optimization of nonlinear systems. The inertia weights approach (IWA) and the constriction factor approach (CFA) are improved methods in PSO. The IWA searches the problem space globally in the early steps, and finally searches locally near the optimal solution. CFA is a method that introduces a new parameter into velocity update equation.

This paper proposes a combination of IWA and CFA (the Inertia Weights Constriction Factor Approach: IWCFA), and PSOrank, whose objective is the ranking of individuals in the population. These two proposed methods are applied to function optimizations and to the portfolio selection problem, which is a typical mathematical problem in securities finance. The results show that the original PSO finds better solutions than the GA, and the proposed method finds better solutions than the original PSO. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(3): 13–25, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20263
Interleukin‐10 derived from macrophages and/or neutrophils regulates the inflammatory response to LPS but not the response to CpG DNA
Authors: Siewe Lisa , Bollati–Fogolin Mariela , Wickenhauser Claudia , Krieg Thomas , Müller Werner , Roers Axel
Published: November 2006

Interleukin‐10 (IL‐10) is an important regulator of immune responses secreted by different cell types. We have previously shown that mice with selective inactivation of the IL‐10 gene in T cells suffer from deregulated T cell responses similar to those observed in IL‐10–/– animals. Unlike IL‐10–/– mice, however, T cell‐specific mutants do not mount an enhanced innate immune response to LPS, which must, therefore, be subject to control by IL‐10 from non‐T cells. Herein we show that subcutaneous injection of LPS, which causes moderate local inflammation in WT and T cell‐specific IL‐10 mutant mice, results in augmented inflammatory infiltration and extensive tissue necrosis in mice with deficiency for IL‐10 in macrophages and neutrophils. Correspondingly, we observed an enhanced sensitivity of the macrophage/neutrophil‐specific IL‐10 mutants to systemic LPS exposure when compared with WT animals. In contrast, the inflammatory response of these mutants to CpG oligodeoxynucleotides was not different from that of WT mice. While IL‐10–/– mice developed massive inflammation, necrosis and increased serum cytokine levels after subcutaneous CpG injection, only moderate responses were observed in macrophage/neutrophil‐specific IL‐10 mutant and WT mice. These results show that different innate immune responses can be subject to control by IL‐10 from different cellular sources.
Inhibitory effect of the polyinosinic‐polycytidylic acid/cationic liposome on the progression of murine B16F10 melanoma
Authors: Fujimura Taku , Nakagawa Satoshi , Ohtani Tomoyuki , Ito Yumiko , Aiba Setsuya
Published: November 2006

Cellular proteins, retinoic acid inducible gene‐I and Toll‐like receptor 3, sense dsRNA including polyinosinic‐polycytidylic acid (PIC) to stimulate innate immune response. The local administration of PIC has been demonstrated to be effective in anti‐tumor immunotherapy. However, the effects of PIC delivered cross the cell membrane have not yet been examined. To address this issue, we used a complex of PIC and cationic liposome (PIC liposome) and examined its anti‐tumor effects in vitro and in vivo. PIC liposome could directly suppress the growth of B16F10 melanoma in vitro and repeated peritumoral injections of PIC liposome inhibited melanoma growth in a dose‐dependent manner. This treatment induced tyrosinase‐related protein‐2 (TRP‐2)‐tetramer+ CD8+ cells in the lymph nodes. As the mechanism for its anti‐tumor immune response, we showed that the intradermal injection of PIC liposome induced the maturation of dendritic cells (DC). Moreover, the intratumoral injection of immature DC after treatment with PIC liposome significantly increased the number of TRP‐2‐specific IFN‐γ‐producing cells in the lymph nodes as well as spleen, which resulted in an augmentation of the anti‐tumor immune response. These studies demonstrate the potential of peritumoral injection of PIC liposome as immunotherapy for malignant melanoma.
Alteration of epitope recognition pattern in Ag85B and ESAT‐6 has a profound influence on vaccine‐induced protection against Mycobacterium tuberculosis
Authors: Bennekov Thomas , Dietrich Jes , Rosenkrands Ida , Stryhn Anette , Doherty T. Mark , Andersen Peter
Published: November 2006

To analyze the effect of vaccine delivery systems on antigen recognition and vaccine efficacy, we compared immune responses in mice immunized either with an adenovirus vector expressing a fusion of Ag85B and ESAT‐6 or with the recombinant fusion protein in a liposomal adjuvant. Both vaccines induced high levels of antigen‐specific IFN‐γ production. The adjuvanted protein vaccine induced primarily a CD4 T cell response directed to the epitope Ag85B241–255 and gave efficient protection against subsequent Mycobacterium tuberculosis infection. In contrast, the adenoviral construct induced a strong CD8 response predominantly targeted to the epitope ESAT‐615–29 and no significant protection against infection. Vaccination with the protein vaccine resulted in highly accelerated recall of Ag85B241–255‐specific T cells immediately post M. tuberculosis challenge whereas the ESAT‐615–29 epitope was barely recognized during infection. Delivery of the viral construct in cationic liposomes switched the immune response to a protective one dominated by CD4 T cells targeted to the Ag85B241–255 epitope. These data demonstrate that the nature of the T cell response to a vaccine antigen is more important than its magnitude with respect to protective efficacy and that vaccine‐mediated changes in immunodominance can result in T cell responses of limited relevance during the natural infection.
Regulation of 2B4 (CD244)‐mediated NK cell activation by ligand‐induced receptor modulation
Authors: Sandusky Mina M. , Messmer Birgitta , Watzl Carsten
Published: November 2006

Natural killer (NK) cell activity can be stimulated by different surface receptors. 2B4 is a member of the signaling lymphocyte activation molecule (SLAM)‐related receptor family and is important for stimulating human NK cell cytotoxicity and cytokine production. Here we show that stimulation of human NK cells by antibody‐mediated 2B4 cross‐linking or incubation with target cells expressing the 2B4 ligand CD48 results in a strong down‐modulation of 2B4 surface expression. This down‐modulation is observed in NK cell lines, purified human NK cells and NK cell clones, and is accompanied by an internalization of 2B4. The modulation of 2B4 is dependent on the activity of Src‐family kinases, but independent of PI3 K activity or actin polymerization. Inhibitory receptors can interfere with 2B4‐mediated signals and NK cell activation. However, co‐engagement of inhibitory killer cell Ig‐like receptors has no influence on the down‐modulation of 2B4. This suggests that the modulation of 2B4 expression is independent of inhibitory receptors. The lower surface expression of 2B4 after ligand‐induced down‐modulation results in reduced 2B4‐mediated NK cell activation and cytotoxicity. The modulation of activating surface receptors may therefore be another mechanism for the fine‐tuning of NK cell activity and may lead to the adaptation of NK cell cytotoxicity in tissues with high ligand expression.
NF‐κB binds to the immunoglobulin Sγ3 region in vivo during class switch recombination
Authors: Wang Lili , Wuerffel Robert , Kenter Amy L.
Published: November 2006

Ig class switch recombination (CSR) is dependent upon the expression of activation‐induced deaminase and targeted to specific isotypes by germ‐line transcript expression and isotype‐specific factors. NF‐κB plays critical roles in multiple aspects of B cell biology and has been implicated in the mechanism of CSR by in vitro binding assays and altered S/S junctions derived from NF‐κB p50‐deficient mice. However, the pleiotropic contributions of NF‐κB to gene expression in B cells has made discerning a direct role for NF‐κB in CSR difficult. We now observe that binding of NF‐κB components p50 and p65 is detected on Sγ3 in vivo following lipopolysaccharide (LPS) activation and repressed by LPS + IL–4, suggesting a direct role for this factor in CSR. In vivo footprinting confirms occupancy of a previously defined NF‐κB recognition site in Sγ3 with the same temporal kinetics as found in the chromatin immunoprecipitation analysis. Binding of NF‐κB components p50 and p65 was also detected on Sγ1 following B cell activation. H3 histone hyper acetylation at Sγ1 is strongly correlated with NF‐κB binding, suggesting that NF‐κB mediates chromatin remodeling in the Sγ3 and Sγ1 region.
Temporal cross‐talk between TCR and STAT signals for CD8 T cell effector differentiation
Authors: Verdeil Grégory , Chaix Julie , Schmitt‐Verhulst Anne‐Marie , Auphan‐Anezin Nathalie
Published: November 2006

The strength and duration of signaling through surface receptors is a primary means of controlling cell fate decisions. In adaptive immunity, Ag‐initiated T cell stimulation is secondarily regulated by cytokines. We here summarize evidence for temporal control of a gene expression program in naive CD8 T cells. It is initiated in response to TCR engagement but relies on secondary signaling from cytokine receptors to be sustained and to allow development of full effector capacity. This mechanism permits cytokine receptor signaling to rescue abortive TCR signaling, such as that induced in response to weak or partial TCR agonists. Indeed, limiting TCR‐initiated signaling on the Ras/ERK pathway may be complemented by STAT activation. Thus, TCR‐ and cytokine‐driven activation of transcription factors and epigenetic modifications may act in concert in a temporally staggered process to establish the functional program of effector CD8 T cells. Based on gene expression profiling, molecular targets whose activation or inactivation may boost or dampen CD8 T cell effectors are also identified. Manipulation of these targets may, respectively, increase anti‐tumor responses or prevent graft‐versus‐host reactions.
Nucleic acid agonists for Toll‐like receptor 7 are defined by the presence of uridine ribonucleotides
Authors: Diebold Sandra S. , Massacrier Catherine , Akira Shizuo , Paturel Carine , Morel Yannis , Reis e Sousa Caetano
Published: November 2006

Toll‐like receptor 7 (TLR7) mediates innate responses by responding to viral RNA in endocytic compartments. However, the molecular pattern recognised by TLR7 and whether it differs between RNA of viral and self origin remains unclear. Here, we identify nucleic acids that act as TLR7 agonists for mouse and human cells. We show that uridine and ribose, the two defining features of RNA, are both necessary and sufficient for TLR7 stimulation, and that short single‐stranded RNA (ssRNA) act as TLR7 agonists in a sequence‐independent manner as long as they contain several uridines in close proximity. Consistent with the notion that TLR7 lacks specificity for sequence motifs, we show that it is triggered equally efficiently by viral or self RNA delivered to endosomes. Our results support the notion that TLR7 recognises uracil repeats in RNA and that it discriminates between viral and self ligands on the basis of endosomal accessibility rather than sequence.
Oxidation of Phosphanes with Orthoquinones: An Unusual Decomposition of an Unexpectedly Stable Zwitterion
Authors: Shevchenko Igor , Andrushko Vasyl , Lork Enno , Röschenthaler Gerd‐Volker
Published: November 2006

Oxidation of the ylide (Et2N)2P[=C(CN)CH(CF3)2]CH2P(NEt2)2 (3) with tetrachloroorthobenzoquinone (TOB) does not give the expected 1,3,2‐dioxaphospholane but stops at the formation of the unusually stable intermediate zwitterion 6. The molecular structure of 6 was established by X‐ray analysis. In solution at temperatures above 15 °C zwitterion 6 undergoes an unusual decomposition into symmetrical carbodiphosphorane 7 and hexafluoroisovaleronitrile 8. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Oriented Crystallisation on Supports and Anisotropic Mass Transport of the Metal‐Organic Framework Manganese Formate
Authors: Arnold Mirko , Kortunov Pavel , Jones Deborah J. , Nedellec Yannig , Kärger Jörg , Caro Jürgen
Published: November 2006

The oriented in situ crystallisation of microporous manganese(II) formate [Mn(HCO2)2] on different porous supports (e.g. porous alumina and graphite) has been investigated. The anisotropic growth of Mn(HCO2)2 was examined by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The intracrystalline diffusion of methanol in Mn(HCO2)2 was studied by observation of the sorption kinetics by interference microscopy (IFM). It was found that untreated discs of porous alumina and graphite supports exhibit poor densities of Mn(HCO2)2 crystals per supported area. Even lower crystal densities are found for activated supports such as for alumina after basic treatment and for oxidized graphite supports. Improved results have been achieved by replacing formic acid by sodium formate in the synthesis route. Crystal growth on graphite gives results superior to those on alumina with respect to the crystal density as well as the relative orientation of the 1D channel network to the support surface. Methanol uptake from the vapour phase is similar at 25 and 40 °C and gives an adsorption capacity of about 95 mL g–1. The BET surface area was found to be 280 m2 g–1. IFM indicates that diffusion occurs only along one crystallographic axis, thus proving the presence of a 1D channel system. Diffusion coefficients of about 10–12 m2 s–1 for methanol in microporous Mn(HCO2)2 were found. These results can be used to prepare supported metal–organic framework (MOF) membranes for molecular sieving. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Thiocyanate Functionalised Ionic Liquids: Synthesis, Characterisation and Reactivity
Authors: Zhao Dongbin , Fei Zhaofu , Han Ang Wee , Scopelliti Rosario , Dyson Paul J.
Published: November 2006

The reaction of chloromethyl thiocyanate with 1‐methylimidazole affords the imidazolium salt, 1‐thiocyanomethyl‐3‐methylimidazolium chloride, [C1SCNmim]Cl (1a). Exchange of the chloride anion in 1a by [PF6]–, [BF4]–, [Tf2N]– or [AuCl4]– affords salts 1b, 1c, 1d and 1e, respectively. Salts [C1SCNmim][BF4] (1c) and [C1SCNmim][Tf2N] (1d) melt below 100 °C and can therefore be classified as ionic liquids. The reaction of 1a with PdCl2 affords [C1SCNmim]2[PdCl4] (2a), whereas 1c reacts with PdCl2 to form the complex [PdCl2{C1SCNmim}2][BF4]2 (2c). In the presence of HNO3 both 1a and 1c react with PdCl2 with the loss of HCN to form a sulfide‐bridged palladium dimer [PdCl2{C1Smim}]2 (3). The structures of 1a, 1e, 2a and 3 have been determined in the solid state by single‐crystal X‐ray diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
The Design of Metal Chelates with a Biologically Related Redox‐Active Part: Conjugation of Riboflavin to Bis(2‐pyridylmethyl)amine Ligand and Preparation of a Ferric Complex
Authors: Thallaj Nasser K. , Mandon Dominique , White Kristen A.
Published: November 2006

Reaction of a twofold molar excess of bis(2‐pyridylmethyl)amine DPA with 8α‐bromoAc4riboflavin in dry DMF over 24 h affords the 8α‐[bis(2‐pyridylmethyl)amine]‐N‐Ac4riboflavin ligand. This compound can be described as a tweezer in which the flavin moiety acts as a potential electron mediator. The trichloroferric complex has been prepared, and together with the low potential reduction wave of the flavin moiety, the presence of a reversible FeIII/FeII couple at a higher potential is observed. The deacetylated ligand 8α‐[bis(2‐pyridylmethyl)amine]‐N‐riboflavin can easily be obtained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
(+)‐Lentiginosine, a Potent and Selective Inhibitor of Amyloglucosidase: Synthetic Efforts and Disputes on Its Absolute Configuration
Authors: Cardona Francesca , Goti Andrea , Brandi Alberto
Published: November 2006

(+)‐Lentiginosine is a powerful and selective inhibitor of amyloglucosidases and has become a reference compound in the field among derivatives related to imino sugars. The present review focuses on the several total syntheses of this alkaloid, which rely on either a chiral pool or on enantioselective approaches that have appeared since its isolation in 1990. A summary of biological assays and molecular dynamic studies which allowed the assignment of the correct absolute configuration of natural (+)‐lentiginosine is reported.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Diastereoselective Reduction of Bicyclic ‐Enamino Carbonyl Piperidines – Application to the Total Synthesis of (–)‐Deoxocassine
Authors: Noël Romain , Vanucci‐Bacqué Corinne , Fargeau‐Bellassoued Marie‐Claude , Lhommet Gérard
Published: November 2006

The chemo‐ and diastereoselective reduction of chiral piperidine β‐enamino esters 4 and 6 and β‐enamino ketones 5 and 7 was studied and found to afford 2,3‐ or 2,3,6‐substituted piperidines. This approach was successfully applied to the total synthesis of (–)‐deoxocassine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A New Family of Biisoquinoline Chelates
Authors: Durola Fabien , Hanss David , Roesel Pirmin , Sauvage Jean‐Pierre , Wenger Oliver S.
Published: November 2006

Four 8,8′‐diaryl‐substituted 3,3′‐biisoquinoline ligands have been synthesized and characterized. The key feature of this new family of chelates is their endotopic but sterically nonhindering nature. All four ligands were made from a common 8‐bromoisoquinolin‐3‐ol precursor; between three and twelve synthetic steps were necessary to obtain the products. The reported synthetic procedures allow for gram‐scale production of these biisoquinolines. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
The relationship between marital standards, dyadic coping and marital satisfaction
Authors: Wunderer Eva , Schneewind Klaus A.
Published: November 2006

Different types of cognitions in close relationships have been identified. Yet, little is known about the nature and effects of most of them, such as marital standards. In our research project ‘What makes marriages last?’ we applied a German adaptation of the ‘Inventory of Specific Relationship Standards,’ a questionnaire measuring how much sharing, egalitarianism and investment spouses feel they should have and actually experience in their own marriage. We hypothesized that high, i.e., relationship‐focused standards, should be associated with dyadic coping processes as well as with marital satisfaction. Thereby, dyadic coping was expected to play a mediating role between standards and marital satisfaction. Based on a sample of 663 German married couples, we found significant correlations between standards, marital satisfaction, and dyadic coping processes. Moreover, supportive behavior in stressful situations had the expected partial mediating effect, which turned out to be slightly different for husbands and wives. Implications for preventive and therapeutic intervention are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Experimental and numerical investigation into leakage effect in injectors of microfluidic devices
Authors: Tsai Chien‐Hsiung , Wang Yao‐Nan , Lin Chiu‐Feng , Yang Ruey‐Jen , Fu Lung‐Ming
Published: November 2006

This paper performs an experimental and numerical investigation into low‐leakage injectors designed for electrophoresis microchips. The principal material transport mechanisms of electrokinetic migration, fluid flow, and diffusion are considered in developing a mathematical model of the electrophoresis process. Low‐leakage injectors designed with injection channels orientated at various included angles are designed and tested. The numerical and experimental results indicate that the injector with a 30° included angle successfully minimizes sample leakage and has an exciting potential for use in high‐quality, high‐throughput chemical analysis procedures and in many other applications in the field of micro‐total analysis systems.
Sacrificial layer microfluidic device fabrication methods
Authors: Peeni Bridget A. , Lee Milton L. , Hawkins Aaron R. , Woolley Adam T.
Published: November 2006

Over the past 15 years, research in the field of microfluidics has experienced rapid growth due to significant potential advantages such as low cost, short analysis times, and elimination of sources of contamination. Although etched and thermally bonded glass substrates have seen widespread use and offer solid performance, device fabrication still remains cumbersome. Recent advances in sacrificial layer microfabrication methods for microfluidics have overcome many disadvantages of conventional fabrication approaches. Phase‐changing sacrificial layers have been implemented in making inexpensive and high‐performance polymer microchips for electrophoretic analysis, protein focusing, and sample preconcentration. In addition, novel channel fabrication methods based on standard thin‐film processes, which are readily integratable with microfabrication techniques used for electrical components, are being applied increasingly for the creation of microfluidic devices. These new sacrificial layer fabrication approaches will be instrumental in making low‐cost and high‐quality polymer microchips, and in interfacing electrical and fluidic systems on glass or semiconductor substrates.
Quantification of Survival of Escherichia coli O157:H7 on Plants Affected by Contaminated Irrigation Water
Authors: Ibekwe A. M. , Shouse P. J. , Grieve C. M.
Published: November 2006

Enterohemorrhagic E. coli O157: H7 (EHEC) is a major foodborne pathogen capable of causing diarrhea and vomiting, with further complications such as hemolytic‐uremic syndrome (HUS). The aim of this study was to use the real‐time PCR method to quantify the survival of Escherichia coli O157:H7/pGFP in phyllosphere (leaf surface), rhizosphere (volume of soil tightly held by plant roots), and non‐rhizosphere soils (sand and clay) irrigated with contaminated water and compare the results obtained between real‐time PCR method and conventional plate counts. The real‐time PCR probe was designed to hybridize with the (eae) gene of E. coli O157:H7. The probe was incorporated into real‐time PCR containing DNA extracted from the phyllosphere, rhizosphere, and non‐rhizosphere soils irrigated with water artificially contaminated with E. coli O157:H7. The detection limit for E. coli O157:H7 quantification by real‐time PCR was 2.3 × 103 in the rhizosphere and phyllosphere samples. E. coli O157:H7 survived longer in rhizosphere soil than the non‐rhizosphere soil. The concentration of E. coli O157:H7/pGFP in rhizosphere soils was ≥ 104 CFU/g in both soils at day 12 based on both plate count and real time PCR, with the clay soil significantly (P = 0.05) higher than the sandy soil. This data showed that E. coli O157H:7 can persist in the environment for more than 50 d, and this may pose some risk for both animal and human infection and provides a very significant pathway for pathogen recontamination in the environment.
Optimizing the Production of Bacterial Cellulose in Surface Culture: Evaluation of Substrate Mass Transfer Influences on the Bioreaction (Part 1)
Authors: Hornung M. , Ludwig M. , Gerrard A. M. , Schmauder H.‐P.
Published: November 2006

The interest in cellulose produced by bacteria from surface cultures has increased steadily in recent years because of its potential for use in medicine and cosmetics. Unfortunately, the low yield of the production process has limited the commercial usefulness of bacterial cellulose. This series of three papers dealing with the production of bacterial cellulose using (batch) surface culture, firstly present a complete and complex analysis of the overall system, which allows a fundamental optimization of the production process to be performed. This material has many applications but the low yield of the process limits its commercial usefulness. In part 1, the effect of the rate of mass transfer of substrate on the microbial process, which is characterized by the growth of the bacteria, product formation, and the utilization of the substrate by the bacteria, is studied. A fundamental model for the diffusion of glucose through the growing cellulose layer is proposed and solved. The model confirmed that the increase in diffusional resistance is indeed significant but other factors will also need to be taken into account.
Feasibility of conducting the micronucleus test in circulating erythrocytes from different mammalian species: An anatomical perspective
Authors: Udroiu Ion
Published: November 2006

The in vivo mammalian micronucleus test can be conducted easily on peripheral blood samples since the maturation of erythrocytes involves the loss of the major nucleus. In addition, mature erythrocytes are relatively long‐lived, so that the test potentially can detect genotoxic damage caused by chronic exposures. However, some species have spleens that remove micronuclei from the peripheral circulation, making such measurements problematical. This report summarises haematological and mutagenesis studies dealing with this subject and provides an anatomical interpretation of the phenomenon. Anatomical features can be used to identify those species in which micronuclei are removed by the spleen. Environ. Mol. Mutagen., 2006. © 2006 Wiley‐Liss, Inc.
Laboratory tests of steel simple torsionally unbalanced models
Authors: De‐la‐Colina Jaime , Acuña Qutberto , Hernández Alejandro , Valdés Jesús
Published: November 2006

The objective of this work is to obtain estimations of the amplification factors α and δ used for torsion design of buildings, from experiments. For this study, simple one‐storey torsionally unbalanced (TU) steel models were considered. Models consisted of a deck supported on four columns with a selected arrangement of hinges at column ends. Two theoretical structural eccentricities (e = 0.05 and 0.15) were considered. Models were excited with a simple long‐period pendulum consisting of a hanging platform with a forced‐vibration generator on it. Eight models were tested at several excitation levels (frequencies and force magnitudes) in both ranges of behaviour: elastic and inelastic. Experiments were conducted at three frequency ratios of excitation. Registered accelerations of the pendulum platform indicate that the experimental set‐up leads to excitations that resemble narrow‐band seismic ground motions. Frame shear force estimations, based on accelerations recorded at both deck sides, indicate that torsion design factors (α and δ) depend on eccentricity. Estimations of frame shears based on measurements indicate that for normalized eccentricities e ⩾ 0.025, the amplification α can be between 2 and 3; while δ factor resulted between 0.0 and 1.6. Copyright © 2006 John Wiley & Sons, Ltd.
Controlling the thermal environment in hot spots of buried power cables
Authors: Klimenta D. , Nikolajević S. , Sredojević M.
Published: November 2006

An approach to numerical modelling of temperature distributions around buried power cables using finite element analysis is presented in this paper. The finite element algorithms are based on time‐dependent heat sources of the environment and temperature‐dependent material properties of the cables. The nonlinear steady‐state and transient heat transfer algorithms are applied to the problem of controlling thermal environment in an actual hot spot of a 110 kV cable line installed in Belgrade, Republic of Serbia. Moreover, this paper outlines the influence of an underground heating pipeline on ampacities of the cable line, and two retrofitting procedures for optimising the thermal properties of cable environment. Two suggested procedures for thermal optimisation of the actual hot spot are: the use of a new‐mixed corrective backfill and the use of quartz sand. Finally, actual test cases using the measured data indicate the possibilities of using the proposed algorithms. Copyright © 2006 John Wiley & Sons, Ltd.