bluuebunny/crossref_metadata_2025 huggingface dataset:
Interchangeable functions ofArabidopsisPIROGI and the human WAVE complex subunit SRA1 during leaf epidermal development
Authors: Basu Dipanwita , El-Assal Salah El-Din , Le Jie , Mallery Eileen L. , Szymanski Daniel B.
Published: August 2004

The WAVE complex is an essential regulator of actin-related protein (ARP)2/3-dependent actin filament nucleation and cell shape change in migrating cells. Although the composition of the WAVE complex is well characterized, the cellular mechanisms that control its activity and localization are not well known. The `distorted group' defines a set of Arabidopsis genes that are required to remodel the actin cytoskeleton and maintain the polarized elongation of branched, hair-like cells termed trichomes. Several loci within this group encode homologs of ARP2/3 subunits. In addition to trichome distortion, ARP2/3 subunit mutants have reduced shoot fresh weight and widespread defects in epidermal cell-cell adhesion. The precise cellular function of plant ARP2/3, and the means by which it is regulated, is not known. In this paper, we report that the `distorted group' gene PIROGI encodes a homolog of the WAVE complex subunit SRA1. The similar cell shape and actin phenotypes of pir and ARP2/3 complex subunit mutants suggest that PIROGI positively regulates ARP2/3. PIROGI directly interacts with the small GTPase ATROP2 with isoform specificity and with selectivity for active forms of the protein. PIROGI shares only 30% amino acid identity with its human homolog. However, both WAVE subunit homologs are functionally interchangeable and display identical physical interactions with RHO family GTPases and the Arabidopsishomolog of the WAVE complex subunit NAP125. These results demonstrate the utility of the `distorted group' mutants to study ARP2/3 complex functions from signaling input to cell shape output.
MicroRNA regulation of the CUC genes is required for boundary size control inArabidopsismeristems
Authors: Laufs Patrick , Peaucelle Alexis , Morin Halima , Traas Jan
Published: August 2004

We have analysed the role of a microRNA, miR164, in boundary formation during organ initiation from Arabidopsis meristems. The establishment and maintenance of the boundary domain are controlled by three partially redundant genes, CUP-SHAPED COTYLEDON1 (CUC1), CUC2 and CUC3. We show that miR164 overexpression phenocopies the cuc1 cuc2 double mutant by inducing post-transcriptional downregulation of CUC1 and CUC2 but not CUC3 mRNA levels. Disruption of CUC2 regulation by miR164, either by making CUC2 resistant to the miRNA or by reducing miRNA levels leads to similar enlarged boundary domains. We relate this enlargement to the division patterns of the boundary cells. We propose that miR164 constrains the expansion of the boundary domain, by degrading CUC1 and CUC2 mRNAs.
Target-identical rapid control prototyping platform for model-based engine control
Authors: Lee Wootaik , Shin Minsuk , Sunwoo Myoungho
Published: August 2004

Rapid control prototyping (RCP) is one of the most important technologies for speeding up the development process of the electronic control unit (ECU) used in the automotive control system. However, one big drawback of the conventional RCP platform is the transfer from RCP to target ECU implementation. In this study, a new RCP platform is proposed that provides a consistent environment for both the RCP development stage and the target ECU implementation stage. In order to make the rapid prototyping controller as similar to a production ECU as possible, the prototyping system follows the strictly layered architecture of the production ECU and separates the automatically generated code of software from the hand code. Finally, the feasibility of the developed target-identical RCP platform is evaluated through an air-to-fuel ratio (AFR) control application.
Experimental analysis of a liquid-phase liquefied petroleum gas injector for a heavy-duty engine
Authors: Sim Hansub , Lee Kangyoon , Chung Namhoon , Sunwoo Myoungho
Published: August 2004

Liquefied petroleum gas (LPG) is a well-known clean alternative fuel for vehicles. In a heavy-duty, liquid-phase LPG injection (LPLi) system, several factors influence the amount of fuel injected. These factors are fuel temperature, fuel injection pressure, battery voltage, and so on. In order to maintain the stoichiometric air-fuel ratio in the cylinder during engine operation, the injected fuel quantity should be controlled accurately. In this study, the characteristics of the injector used in the heavy-duty LPLi engine are investigated experimentally. The fuel injection algorithm, which compensates for the variations in the injection pressure, the fuel temperature and the battery voltage, is developed and verified through engine tests.
Investigation of atomization and evaporation characteristics of high-pressure injection diesel spray using Kelvin—Helmholz instability/droplet deformation and break-up competition model
Authors: Park Sung Wook , Sik Lee Chang
Published: August 2004

This paper describes a numerical investigation into the atomization and evaporation characteristics of common-rail diesel injection spray using the KH-DDB (Kelvin-Helmholz instability/droplet deformation and breakup) competition model and the evaporation model. The predicted results, such as the images of spray development and SMD distribution, were obtained by using the KH-DDB competition breakup model at different injection pressures. To verify the prediction accuracy of the competition breakup model, the experiments on the atomization of common-rail diesel injector were conducted by using a PDPA (phase Doppler particle analyser) system and laser sheet method, and the experimental results on the atomization characteristics were compared with the predicted results. Also the numerical study of the evaporation characteristics of high-speed diesel spray were performed by using the proposed breakup model.

It was revealed that the TAB (Taylor analogy breakup) model predicts the excessive atomization at the early stage of injection duration, whereas the KH-DDB model predicts it properly. From this point of view, the prediction accuracy of the KH-DDB competition model on the mean droplet size distribution is improved compared with the results of the TAB model, the original breakup model of KIVA-3 code. The numerical results of spatial distribution of droplet breakup indicate that both the primary and secondary breakup happen most actively at 0.7 ms after start of injection and 10 mm downstream from the injector tip.
Performance evaluation of traction control systems using a vehicle dynamic model
Authors: Song Jeonghoon , Boo Kwangsuck
Published: August 2004

This study evaluates traction control systems (TCSs) composed of either a wheel slip controller or a throttle valve controller, or an integrated controller of both systems. The dynamic characteristics of a vehicle and a TCS are evaluated using a proposed full car model that can simulate the responses of both front-wheel-drive and four-wheel-drive vehicles. A driver model is also modified to control the vehicle during tests on a road with split Coefficients. The results show that the brake TCS provides more acceleration on uniform slippery and split roads, but the yaw rate and the lateral off set are larger than those obtained when an engine TCS is used. When the vehicle is cornering and accelerating with the brake or engine TCS, understeer or oversteer occur, depending on the driving conditions. An integrated TCS prevents most of these problems and improved the stability and controllability of the vehicle. Four-wheel-drive vehicles exhibit better traction control than two-wheel-drive vehicles, but their steerability is reduced.
Electromagnetic compatibility performance of large area flexible printed circuit automotive harness
Authors: Webb D P , Jaggernauth W A , Cottrill M W C , West A A , Conway P P , Palmer P J
Published: August 2004

Electrical interconnection is increasingly important to the functionality of modern vehicles. At the same time the drive within the industry to reduce costs and improve fuel efficiency requires the reduction of the weight of vehicles wherever possible. It is in this context that the possibility of using large-area flexible printed circuits (FPCs) in place of wiring harnesses is receiving strong interest from manufacturers. An FPC harness offers a substantial weight reduction over wire, improved reliability and quality control, and enhanced functionality. Since good electromagnetic compatibility (EMC) design and performance is necessary for the safe and proper functioning of a vehicle, it is important to know if the EMC performance of a vehicle is likely to be compromised by the incorporation of an FPC harness. This question is addressed in this work by comparing the performance of wire and FPC structures in a standard EMC test. The cost implications of anti-interference measures for mass production of FPC harnesses are also assessed. It is found that relatively cheap and simple to implement track structures can significantly reduce the amount of coupling to a large-area FPC automotive harness from an external electromagnetic field.
Experimental validation of a fuel additive assisted regeneration model in silicon carbide diesel filters
Authors: Stratakis G A , Pontikakis G N , Stamatelos A M
Published: August 2004

In this paper, an experimental validation procedure is applied to an improved one-dimensional model of fuel additive assisted regeneration of a diesel particulate filter. Full-scale tests on an engine bench of the regeneration behaviour of a diesel filter fitted to a modern diesel engine run on catalyst- doped fuel are employed for this purpose. The main objectives of the validation procedure concern the ability of the model to predict the effects of exhaust mass flowrate, initial soot loading mass, volatile organic fraction of the soot and additive concentration in the fuel. The results of the validation procedure are intended to demonstrate the scope and extent of applicability of models of this type to real-world design and optimization studies with diesel filters.
Vehicle modal emissions measurement—techniques and issues
Authors: Hawley J G , Bannister C D , Brace C J , Cox A , Ketcher D , Stark R
Published: August 2004

The measurement of vehicle modal emissions is technically challenging owing to the major issue of determining exhaust-gas mass flowrate and ensuring that it is synchronous with the corresponding ‘slug’ of gas to be measured. This is also extended to the simultaneous measurement of pre- and post-catalyst emissions to determine small passive NOx conversion efficiencies. Although only really evident for passive NOx conversion efficiencies where the magnitude of catalyst performance is low in comparison to HC and CO, a misalignment between these measuring points of between will cause the resulting NOx conversion efficiency to lie anywhere between 0 per cent and 20 per cent. Further alignment issues arise when the CO2 tracer method is used for determining exhaust-gas volume flowrates. The sensitivity of time-alignment along with techniques and associated issues concerned with modal gas-flow measurement is presented in this paper.
Development of a piezoelectrically-controlled hydraulic actuator for a camless engine. Part 2: System modelling
Authors: Brader J S , Rocheleau D N
Published: August 2004

An analysis of existing models for hydraulic servo valves is presented for use in simulations of a camless engine actuator. Because of the limitations of the accepted models, a new servo valve model is derived, presented and verified. The updated model allows for more complex internal geometry, including new port shapes and port lapping parameters. Comparative results are presented, outlining the significant improvement in valve lift versus time simulation of the newly derived model. The improved model results allow for better simulations and control system design for camless engine valve actuators.
Advanced hybrid neural network automotive friction component model for powertrain system dynamic analysis. Part 1: Model development
Authors: Cao M , Wang K W , Fujii Y , Tobler W E
Published: August 2004

An accurate and easy-to-implement dynamic friction component model is necessary for powertrain system design and performance studies. A neural network approach developed by Cao et al. [1] for friction component modelling has illustrated some very promising results. However, this model has complex architecture that may lead to reduced training efficiency; also, owing to the lack of time information, the network cannot adapt to time step variations. Therefore, it cannot be easily integrated with powertrain system models, which in general require variable time steps for superior numerical integration performance. In this paper, a new first-principle-based hybrid network friction component model, the advanced hybrid neural network (AHNN), is derived for dynamic engagement analysis with variable time steps. With improvement over the previous work by Cao et al. [1], the time pattern information is added to the inputs and a simpler architecture is developed through more explicit utilization of the physical laws. With these new features, the AHNN model can significantly out-perform the previous approach. The network is trained and tested using experimental data as well as analytical results. It is shown that this new model can compensate for time step variations and can predict the friction component torque accurately for a wide range of operating conditions. This is Part 1 of a two-part paper. In Part 2, the AHNN friction component model is integrated with a powertrain model and implemented for system simulations.
Electrical conductivity spectra of smectites as influenced by saturating cation and humidity
Authors: Logsdon Sally D. , Laird David A.
Published: August 2004

Electrical conductivity is an important soil property related to salinity, and is often used for delineating other soil properties. The purpose of this study was to examine the influence of smectite properties on the complex electrical conductivity spectra of hydrated smectitic clays. Four smectites were saturated with Ca, Mg, Na or K and equilibrated at four relative humidities ranging from 56 to 99%. X-ray diffraction was used to determine fractions of the various smectite layer hydrates (0 to 4 layers of interlayer water molecules) in each sample. A vector network analyzer was used to determine the real component of the complex electrical conductivity spectra (σ′) for frequencies (f) ranging from 300 kHz to 3 GHz. Values of the dc electrical conductivity(σ0), the frequency where the slope changes in the spectra (fr), and the slope at the high-frequency end of the spectra (n) were determined by fitting σ′ to σ′(f) = σ0(1 + f/fr)n. Both σ0 and fr increased with the total amount of water, the amount of interlayer water, and, for saturating cations in the order K < Mg < Ca < Na. The opposite trends were observed for n. The values of these parameters were influenced by the type of smectite, but the trends were not consistent for the effect of layer charge. The results indicate that interlayer water in smectites contributes to the electrical conductivity of hydrated smectites, and that polarization of water by local electrical fields has a substantial influence on the complex electrical conductivity spectra of smectites. The accuracy of salinity estimates for soils and sediments that are based on conductivity measurements maybe adversely affected unless the effects of hydrated clays on electrical conductivity are considered.
On the mechanisms of apophyllite alteration in aqueous solutions. A combined AFM, XPS and MAS NMR study
Authors: Aldushin Kirill , Jordan Guntram , Fechtelkord Michael , Schmahl Wolfgang W. , Becker Hans-Werner , Rammensee Werner
Published: August 2004

Apophyllite, a hydrous K-Ca-phyllosilicate, reacts with acidic aqueous solutions at room temperature. Various analytical methods have been applied to study the mechanism of the reaction and its characteristics, i.e. the changes in chemical composition, modifications in crystal structure and alterations in surface morphology. In contact with acidic solution, protonation of the terminal, non-bridging oxygen at the silicate tetrahedra takes place and the interlayer cations K+ and Ca2+ are removed. The protonation and ion removal causes the interlayer spacing to increase. Atomic force microscopy shows that the increase takes place discontinuously and, therefore, reflects a discontinuous reaction that comprises a two- or three-step protonation. Additionally, three structurally different protonation sites have been detected by nuclear magnetic resonance spectroscopy which also differ in the amount of close-by hydrogen, although in pristine apophyllite all terminal oxygen positions at silicate tetrahedra are structurally equivalent. In many clay minerals such structurally different protonation sites have not been detected so far. Thus, the multi-step protonation process in apophyllite clearly demonstrates the vast sensitivity of the protonation reaction on small structural variations in phyllosilicates.
Mineralogical and chemical characterization of sepiolite occurrences at Karapinar (Konya Basin, Turkey)
Authors: Karakaya N. , Karakaya M. Çelik , Temel A. , Küpeli Ş. , Tunoğlu C.
Published: August 2004

The Konya region in central Anatolia is covered by Pliocene-Late Pleistocene sediments and volcanites related to the sediments NNW of Karapınar, Turkey. In the area, the Upper Miocene-Quaternary Üzecek Dağı and Karacadağ volcanites are generally of the same age and formed from magmas of similar composition. The Karapınar formation is brown to whitish-beige, partly fossiliferous and consists of limestone, marl, claystone and, locally, sandy layers. Silica-rich lenses, nodules and layers are observed in the upper strata which locally contain sepiolite-rich layers. The mineralogical composition of sepiolite samples taken from the area was determined by powder X-ray diffractometry, while the abundance of major-element oxides was measured by X-ray fluorescence spectrometry. The crystallographic and morphological properties of samples were determined by means of scanning electron microscopy and energy dispersive spectroscopy. Samples were taken from three sections and from random locations. Mineral assemblages in the same stratigraphic position are generally similar in the three sections, while the thickness of the individual beds varies between the sections. Dolomite and calcite are the main carbonate minerals in the sections. Sepiolite occurs primarily with dolomite and, locally, dolomite and calcite, and less commonly with just calcite. Generally, quartz, feldspar and mica are found, especially in the upper parts of the sections where tuff is abundant. CaO and MgO dominate the major-element oxides. The CaO content is between 1 and 30% while MgO is 3–21%. Al2O3 and SiO2 are generally higher in the sepiolitic and tuffitic layers. Al2O3 is <3% and SiO2 is between 15–18% in the sepiolitic layers. The average structural formula of sepiolite was calculated as: (Mg7.00Al0.44Fe0.18)(Si11.71Al0.29)O30 (OH)4(OH2)4Ca0.13K0.09Na0.01. Sepiolite occurs as fibers and dolomite as subhedral or euhedral crystals. It is considered that sepiolite was formed either by conversion of dolomite or by direct precipitation from solution under alkaline and saline conditions in the Karapınar paleolake. The paleolake was saturated with respect to Mg, Ca and Si derived from groundwater that percolated along fracture systems.
Sterically Demanding Diphosphonite Ligands –Synthesis and Application in Nickel‐Catalyzed Isomerization of 2‐Methyl‐3‐Butenenitrile
Authors: van der Vlugt Jarl Ivar , Hewat Alison C. , Neto Samuel , Sablong Rafael , Mills Allison M. , Lutz Martin , Spek Anthony L. , Müller Christian , Vogt Dieter
Published: August 2004

The synthesis of a novel class of sterically demanding diphosphonites 1–8, based on rigid backbones, is described. The starting materials are all commercially available and the methodology allows for a modular approach. All ligands have been fully characterized, including an X‐ray crystal structure for compound 1, 4,5‐bis{di[(2‐tert‐butyl)phenyl]phosphonito}‐9,9‐dimethylxanthene. The coordination of these diphosphonite ligands towards Ni(II) and Ni(0) precursors is investigated, both by NMR spectroscopy as well as X‐ray crystallography and compared with the behaviour of diphosphine ligands such as Xantphos. The molecular structure for complex 9, trans‐[NiBr2(1)] is described in detail. The nickel‐catalyzed isomerization of 2‐methyl‐3‐butenenitrile to 3‐pentenenitrile is studied, a relevant step in the industrially important hydrocyanation of butadiene (the DuPont adiponitrile process). Good activities and selectivities to the desired 3‐pentenenitrile are obtained in this reversible CC bond activation reaction.
Selenium‐Catalyzed Carbonylation of Nitroarenes to Symmetrical 1,3‐Diarylureas under Atmospheric Pressure
Authors: Wang Xiaofang , Lu Shiwei , Yu Zhengkun
Published: August 2004

Selenium‐catalyzed carbonylation of nitrobenzene and substituted nitroarenes with CO under atmospheric pressure afforded symmetrical 1,3‐diarylureas in yields up to 94%. A mechanism has been proposed to demonstrate the formation of symmetrical ureas.
Asymmetric Dihydroxylation of Cinnamonitrile to trans‐3‐[(5S,6R)‐5,6‐Dihydroxycyclohexa‐1,3‐dienyl]‐acrylonitrile using Chlorobenzene Dioxygenase in Escherichia coli (pTEZ30)
Authors: Yildirim Selcuk , Zezula Josef , Hudlicky Tomas , Witholt Bernard , Schmid Andreas
Published: August 2004

Asymmetric cis‐dihydroxylations of aromatic compounds are catalyzed by bacterial dioxygenases. In order to prevent through conversion, either dihydrodiol dehydrogenase blocked mutant strains or recombinant bacterial cells are used as biocatalysts for synthetic purposes. We characterized the cis‐dihydroxylation of cinnamonitrile by chlorobenzene dioxygenase (CDO) in recombinant E. coli on different reaction scales. The absolute stereochemistry of the product was determined to be trans‐3‐[(5S,6R)‐5,6‐dihydroxycyclohexa‐1,3‐dienyl]‐acrylonitrile. The cells showed a maximum specific activity of 3.76 U/g cdw in shake‐flask experiments. Stable expression of the dioxygenase genes in E. coli JM101 (pTEZ30) resulted in increasing volumetric productivities. The maximum volumetric productivities of 80 and 92 mg product/L/h were achieved on 2‐L and 30‐L scales, respectively. The specific growth rate correlated with the volumetric productivity during the biotransformations. An average volumetric productivity of 40 mg product/L/h in reactors on 2‐L and 30‐L scales resulted in 0.96 and 16.4 g of isolated product at the end of the biotransformations. This points out the need for metabolically active cells and controllable expression systems for achieving high volumetric productivities for cofactor dependent biooxidations. We have now applied this concept for the asymmetric dihydroxylation of the non‐natural substrate cinnamonitrile using multicomponent CDO in tailored E. coli JM101 in long‐term reactions.
3‐Pyridinesulfonyl Azide: A Useful Reagent for Radical Azidation
Authors: Panchaud Philippe , Renaud Philippe
Published: August 2004

Radical azidations and carboazidations have been achieved using 3‐pyridinesulfonyl azide as azidating agent. Due to its base properties and its polarity, the excess of reagent is readily removed at the end of the reaction by filtration through silica gel or by extraction with either aqueous 1 M HCl or 1 M CuSO4. The use of this reagent greatly facilitates the tedious purifications of the final azides frequently encountered when reactions are run according to the original procedure involving benzenesulfonyl azide.
Relationship between symptom response and oesophageal acid exposure after medical and surgical treatment for gastro-oesophageal reflux disease
Authors: Jenkinson A D , Kadirkamanathan S S , Scott S M , Yazaki E , Evans D F
Published: August 2004

Background

The relationship between symptom severity and objective evidence of gastro-oesophageal reflux disease (GORD) after medical and surgical treatment has recently been questioned. This study aimed to compare the symptomatic and physiological response (as measured by pHmetry) to the treatment of GORD by proton pump inhibitors (PPIs) and by laparoscopic antireflux surgery, and to examine the relationship between the patient's subjective and objective response to treatment of GORD.

Methods

Seventy patients underwent 24-h oesophageal pH measurement and DeMeester symptom assessment (for heartburn and regurgitation, grade 0–3) while off medical treatment, while taking PPIs and after laparoscopic fundoplication.

Results

The median percentage total time with oesophageal pH < 4 off treatment, during medical treatment and after fundoplication was 9·5, 4·3 and 0·5 per cent respectively. After medical treatment 30 patients became asymptomatic although 18 of these still had pathological reflux on pH testing. Of the 19 patients who remained symptomatic after surgery only two had pathological acid reflux.

Conclusion

The symptomatic response of patients to either PPIs or antireflux surgery is a poor indicator of successful treatment in terms of reduced lower oesophageal acid exposure. A high proportion of patients whose symptoms are improved by PPIs still have pathological levels of acid reflux. Conversely, most patients who complain of reflux symptoms after antireflux surgery have no evidence of residual reflux on pHmetry.
Evidence-based surgery
Authors: Ubbink D T , Legemate D A
Published: August 2004

Patient Safety Leading Article Series, 2004 Continuing the Journal's ‘Patient Safety’ series, Ubblink and Legemate remind readers that only 24 per cent of surgery is based on evidence from randomized clinical trials. Expert opinion, intuition and the tradition of experience are fallible.
Enantioselective Hydrogenation of Alkenes with Iridium–PHOX Catalysts: A Kinetic Study of Anion Effects
Authors: Smidt Sebastian P. , Zimmermann Nicole , Studer Martin , Pfaltz Andreas
Published: August 2004

In the asymmetric hydrogenation of unfunctionalized olefins with cationic iridium–PHOX catalysts, the reaction kinetics and, as a consequence, catalyst activity and productivity depend heavily on the counterion. A strong decrease in the reaction rate is observed in the series [Al{OC(CF3)3}4]−>BArF−>[B(C6F5)4]−>PF6−≫BF4−>CF3SO3−. With the first two anions, high rates, turnover frequencies (TOF>5000 h−1 at 4 °C), and turnover numbers (TONs) of 2000–5000 are routinely achieved. The hexafluorophosphate salt reacts with lower rates, although they are still respectable; however, this salt suffers from deactivation during the reaction and extreme water‐sensitivity, especially at low catalyst loading. Triflate and tetrafluoroborate almost completely inhibit the catalyst. In contrast to the hexafluorophosphate salt, catalysts with [Al{OC(CF3)3}4]−, BArF−, and [B(C6F5)4]− as counterions do not lose activity during the reaction and remain active, even after all the substrate has been consumed. In addition they are much less sensitive to moisture and, in general, rigorous exclusion of water and oxygen is not necessary. A first‐order rate dependence on the hydrogen pressure was determined for the BArF− and the PF6− salts. At low catalyst loading, the rate dependence on catalyst concentration was also first order. The rate dependence on the alkene concentration was strikingly different for the two salts. While the reaction rate observed for the BArF− salt slightly decreased with increasing alkene concentration (rate order −0.2), a rate order of ≈1 was determined for the corresponding hexafluorophosphate at low alkene concentrations.
CCL25/CCR9 promotes the induction and function of CD103 on intestinal intraepithelial lymphocytes
Authors: Ericsson Anna , Svensson Marcus , Arya Anu , Agace William W.
Published: August 2004

The integrin CD103 and the chemokine receptor CCR9 are co‐expressed on small intestinal CD8+ intraepithelial lymphocytes (IEL), naïve murine CD8+ T cells and by a small population of effector/memory CD8+ T cells, indicating a potential role for CCR9 in regulating CD103 expression and function. Here, we demonstrate that CD103, in contrast to CCR9, is down‐regulated on CD8+ T cells following their activation in mesenteric lymph nodes and that effector CD8+ T cells upon initial entry into the small intestinal epithelium are CCR9+CD103–. CD103 was rapidly induced on wild‐type CD8+ T cells subsequent to their entry into the small intestinal epithelium, however, CCR9–/– CD8+ T cells exhibited a significant delay in CD103 induction at this site. In addition, the CCR9 ligand, CCL25, that is constitutively expressed in the small intestinal epithelium, induced transient, dose‐dependent and pertussis toxin‐sensitive CD103‐mediated adhesion of CD8+ small intestinal IEL to a murine E‐cadherin human Fc (mEFc) fusion protein. Together, these results demonstrate a role for CCR9/CCL25 in promoting the induction and function of CD103 on CD8+ IEL and suggest that this chemokine receptor/chemokine pair may function to regulate lymphocyte‐epithelial interactions in the small intestinal mucosa.
Type V collagen regulates the expression of apoptotic and stress response genes by breast cancer cells
Authors: Luparello Claudio , Sirchia Rosalia
Published: August 2004

Type V collagen is a “minor” component of normal human breast stroma, which is subjected to over‐deposition in cases of ductal infiltrating carcinoma (DIC). We reported that, if used as a culture substrate for the DIC cell line 8701‐BC, it exhibited poorly‐adhesive properties and restrained the proliferative and motile behavior of the cell subpopulation able to attach onto it. Moreover, this collagen species was able to trigger DNA fragmentation and impair survival of 8701‐BC cells. In this study, we have extended our investigation with the aim to obtain further evidence that the death induced by type V collagen was of the apoptotic type by (i) microscopic detection and quantitation of Apoptag‐labeled cells, (ii) analysis of the expression levels of selected genes coding for apoptosis‐linked factors, caspases, and stress‐response proteins by conventional and semi‐quantitative multiplex PCR, and (iii) evaluation of the extent of caspase activation by chromogenic assay. We report here that type V collagen is able to determine an increase in the percentage of Apoptag‐positive cells, to up‐regulate Bcl‐xS, Bad, Dap kinase, hsf‐1, mthsp75, caspase‐1, ‐5, ‐8, ‐9, and ‐14, whilst down‐regulating Bcl‐2, Bcl‐xβ, and hsp60. Treatment of cell lysates with chromogenic tetrapeptide substrates specific for caspase‐1, ‐5, ‐8, and ‐9 demonstrated a marked increase of enzymatic activity in the presence of type V collagen. Our data validate 8701‐BC cell line as a suitable “in vitro” model for further and more detailed studies on the molecular mechanisms of the death response induced by type V collagen on primary DIC cells. © 2004 Wiley‐Liss, Inc.
Methylation‐regulated expression of cancer testis antigens in primary effusion lymphoma: Immunotherapeutic implications
Authors: Calabrò Luana , Fonsatti Ester , Altomonte Maresa , Pezzani Laura , Colizzi Francesca , Nanni Paola , Gattei Valter , Sigalotti Luca , Maio Michele
Published: August 2004

Primary effusion lymphoma (PEL) is a large B‐cell neoplasm with an unfavorable prognosis and limited therapeutic options. In this study, cancer testis antigens (CTA) were investigated as potential immunotherapeutic targets in patients with PEL. Baseline expression of a panel of 11 CTA was highly heterogeneous among five PEL cell lines. In particular, the investigated CTA were not expressed in BC‐2 and BC‐3 cells, while BC‐1, HBL‐6, and BCBL‐1 cells tested positive for 6, 8, and 9 CTA, respectively. The DNA hypomethylating agent 5‐aza‐2′‐deoxycytdine (5‐AZA‐CdR) invariably induced or up‐regulated the expression of all investigated CTA in all cell lines analyzed. The de novo expression of CTA was still detectable at mRNA and protein level at least 2 months after the end of 5‐AZA‐CdR treatment. These findings, and the concomitant up‐regulation of HLA‐class I antigens and ICAM‐1 by 5‐AZA‐CdR, support its clinical use to set‐up innovative chemo‐immunotherapeutic approaches in PEL. © 2004 Wiley‐Liss, Inc.
Cysteine‐protease involved in male chromatin remodeling after fertilization co‐localizes with α‐tubulin at mitosis
Authors: Concha Carolina , Morin Violeta , Bustos Paula , Genevière Anne Marie , Heck Margarete M.S. , Puchi Marcia , Imschenetzky Maria
Published: August 2004

We postulated an essential role for a cysteine‐protease in sea urchins sperm histones degradation which follows fertilization. We now report the purification of this enzyme, the determination of its N‐terminal amino acid sequence and the localization of the protein with antibodies generated against this amino‐terminal peptide. The immunofluorescence data confirmed the presence of this enzyme in the nucleus of unfertilized eggs. After fertilization labeling is observed both in female and male pronuclei suggesting a rapid recruitment of the enzyme to the male pronuclei. Interestingly, we have found that this cysteine‐protease persists in the nucleus of the zygotes during S phase of the cell cycle and co‐localizes with α‐tubulin that organizes the mitotic spindle during the initial embryonic cell division. © 2004 Wiley‐Liss, Inc.
Systematic studies of structure and physiological activity of alapyridaine. A novel food‐born taste enhancer
Authors: Soldo Tomislav , Frank Oliver , Ottinger Harald , Hofmann Thomas
Published: August 2004

By application of taste dilution analysis (+)‐(S)‐1‐(1‐carboxyethyl)‐5‐hydroxy‐2‐(hydroxymethyl)‐pyridinium inner salt was recently successfully identified as a multimodal taste enhancer in beef bouillon. While being taste‐less on its own, this so‐called alapyridaine was found to intensify the human perception of sweet, salty, and umami taste. To gain information on the molecular requirements of this novel class of taste enhancer, a range of structurally related pyridinium betaines were synthesized, purified, and their physiological activities sensorially evaluated. Removal or modification of the hydroxyl and the hydroxymethyl group, respectively, induced a loss in bioactivity, thus indicating the 2‐(hydroxymethyl)‐5‐hydroxypyridinium moiety as an essential structural element for taste enhancement. Regarding the amino substituent, neither the prolongation or removal of the alkyl chain or the carboxy function in the 1‐(1‐carboxy‐2‐ethyl)‐moiety, nor the incorporation of an additional carboxy function led to any active derivative, thus demonstrating that also the structure of the nitrogen substituent is rather conserved for taste enhancement. But substitution of the methyl group by a benzyl group yielded a compound showing similar taste enhancing activities as found for alapyridaine. Interestingly, additional insertion of glycine between the 1‐(1‐carboxy‐2‐phenylethyl)‐moiety and the pyridinium ring resulted in a compound eliciting comparable taste enhancing effects as shown for the compound lacking the glycine spacer. In contrast to these multimodal taste enhancers, substitution of the alanine moiety in alapyridaine by an arginine moiety revealed an one‐dimensional taste enhancer exclusively increasing the human sensitivity for salty taste.
Antioxidant activity of plant extracts on the inhibition of citral off‐odor formation
Authors: Liang Chia‐Pei , Wang Mingfu , Simon James E. , Ho Chi‐Tang
Published: August 2004

Grape seed, pomegranate seed, green tea, and black tea extracts were used to inhibit the off‐odor from citral degradation. A 0.1 M citrate buffer (pH 3), containing 100 ppm citral and 200 ppm gallic acid equivalent plant extract, was incubated at 40°C. The reaction mixtures were analyzed by high‐performance liquid chromatography (HPLC) at days 0, 6, 10, 13, and 16 to monitor degradation of citral and formation of α, p‐dimethylstyrene, p‐cymene‐8‐ol, and p‐methylacetophenone. The addition of plant phenolic extracts could not inhibit citral degradation, however, all four plant extracts significantly inhibited p‐methylacetophenone formation. The samples, with the addition of plant extracts, exhibited higher concentrations of α, p‐dimethylstyrene and p‐cymene‐8‐ol than the control. This is presumed to be due to the oxygen‐scavenging effect of plant extracts blocking the pathway from p‐cymene‐8‐ol to p‐methylacetophenone. Our results suggest that these plant extracts act as general antioxidants inhibiting the generation of p‐methylacetophenone regardless of the types of water‐soluble phenolic compounds existing in the plant extracts.
Coupled‐cluster studies of HOONO+: Additional conformers of the 2A″ON+OOH complex and a comparison of restricted and unrestricted open‐shell Hartree–Fock coupled‐cluster results
Authors: Watts John D. , Francisco Joseph S.
Published: August 2004

Coupled‐cluster calculations using the CCSD(T) method (coupled‐cluster singles and doubles with perturbative inclusion of triple excitations) and correlation‐consistent basis sets have been used to address aspects of the lowest 2A′ and 2A″ potential energy surfaces of the peroxynitrous acid cation (HOONO+). First, searches were made for conformers of the 2A″ ON+OOH complex in addition to the cis–trans species previously located by the authors (J Chem Phys 2003, 118, 1721). Two conformers were located—namely, trans–cis and trans–trans species—and these were confirmed to be local minima. The trans–trans conformer was calculated to be less than 0.5 kcal mol−1 higher in energy than the cis–trans conformer, and the trans–cis conformer was calculated to be about 6.4 kcal mol−1 higher in energy than the cis–trans conformer. Second, comparisons were made between CCSD(T) results obtained with unrestricted Hartree–Fock (UHF) and restricted open‐shell Hartree–Fock (ROHF) reference determinants. These comparisons were made on the 2A″ complexes and the planar 2A′ HOONO+ stationary points. In general, the energy differences between UHF‐CCSD(T) and ROHF‐CCSD(T) were very small, and well within the error bars of the methods. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
MIMO ARIMA models for handoff resource reservation in multimedia wireless networks
Authors: Rožić Nikola , Kandus Gorazd
Published: August 2004

This paper presents a new approach to prediction of resource demand for future handoff calls in multimedia wireless IP networks. Our approach is based on application of multi‐input‐multi‐output (MIMO) multiplicative autoregressive‐integrated‐moving average (ARIMA) (p,d,q)x(P,D,Q)S models fitted to the traffic data measured in the considered cell itself and on the new call admission control (CAC) algorithm that simultaneously maximizes the system throughput while keeping the handoff call dropping probability (CDP) below the targeted value. The main advantages of the proposed approach are the following: first, the proposed multi‐variable prediction method gives on average better predictions (i.e. narrower prediction confidence interval) for realistic traffic situations, which results in lower new call blocking probability (CBP) at the targeted handoff CDP and second, the model is simple to implement since it does not require communication among the adjacent cells. Simulation results show the superiority of the proposed MIMO prediction approach combined with the proposed call admission control algorithm for some typical nonstationary situations in comparison with univariate models. Copyright © 2004 John Wiley & Sons, Ltd.
Dynamic resource scheduling (DRS): a multimedia QoS framework for W‐CDMA
Authors: Gürbüz Özgür , Owen Henry
Published: August 2004

Multi‐media support is an important feature of third generation (3G) wireless communication systems, and Quality of Service (QoS) is a crucial issue, as in any other networking environment. In this paper, the QoS issues in the wireless last‐mile is investigated for 3G systems based on Wideband‐Code division multiple access (W‐CDMA). Supporting multiple rates in the CDMA environment introduces the power assignment problem, which is coupled with the bandwidth and error QoS parameters. Also, multi‐media traffic flows should be classified and serviced in such a way to provision delay guarantees. In this paper, a new framework, namely dynamic resource scheduling (DRS), is described and extensively studied. In order to serve multi‐media services with different requirements, a family of nine algorithms has been developed within the DRS framework. These algorithms can be categorized with respect to single or prioritized queuing architectures, fixed or variable rate bandwidth and power allocation, and variable spreading gain or multi‐code spreading strategies. The paper presents the performance of the DRS algorithms in comparison with each other and with conventional scheduled‐CDMA (S‐CDMA) and proposed schemes in the W‐CDMA standard. The performance for error and throughput QoS provisioning and power control dynamics are explored; advantages, disadvantages and limitations of the algorithms are discussed. The DRS framework is concluded to be a promising QoS architecture, with a simple, flexible, scalable structure that can be configured according to a given traffic scenario. Copyright © 2004 John Wiley & Sons, Ltd.
Prions of yeast fail to elicit a transcriptional response
Authors: Ross Eric D. , Wickner Reed B.
Published: August 2004

Amyloid deposits are associated with numerous human diseases. The [URE3] prion of Saccharomyces is an infectious, inactive, amyloid form of the Ure2p protein. Despite the presence of large prion aggregates in [URE3] yeast, the only apparent phenotypes associated with the prion are attributable to loss of Ure2p function. We used cDNA microarrays to look for genes in yeast that are differentially expressed in the presence of the [URE3] prion and which might act to mitigate the detrimental effects of the prion aggregates. On comparing [URE3] vs. ure2 yeast, we were surprised to find that the only expression changes detected were attributable to the low level of residual Ure2p activity in the [URE3] cells. Interestingly, in addition to repressing the activity of genes required for utilization of poor nitrogen sources when yeast are grown in the presence of a good nitrogen source, Ure2p appears to be involved in stimulating some of these same genes in the absence of a good nitrogen source. Copyright © 2004 John Wiley & Sons, Ltd.
Impairment of homologous recombination control in a Fanconi anemia‐like Chinese Hamster Cell mutant
Authors: Larminat Florence , Germanier Maryse , Papouli Efterpi , Defais Martine
Published: August 2004

Summry— DNA interstrand cross‐links (ICL)‐inducing agents such as cisplatin, mitomycin C (MMC) and nitrogen mustards are widely used as potent antitumor drugs. Although ICL repair mechanism is not yet well characterized in mammalian cells, this pathway is thought to involve a sequential action of nucleotide excision repair (NER) and homologous recombination (HR). The importance of unraveling ICL repair pathways is highlighted by the hypersensitivity to ICL‐inducing agents in cells of patients with the genetic disease Fanconi anemia (FA) and in cells mutated in the Breast Cancer susceptibility genes BRCA1 and BRCA2. To better characterize the involvement of HR in the sensitivity to ICL‐inducing agents, we examined spontaneous and ICL‐induced HR in rodent FA‐like V‐H4 cells. In this report, we show that MMC‐hypersensitive V‐H4 cells exhibit an increased spontaneous homology‐directed repair (HDR) activity compared to the resistant V79 parental cells. Elevated HDR activity results mainly in increased conservative Rad51‐dependent recombination, without affecting non‐conservative single‐strand annealing process (SSA). We also show that HDR activity is enhanced following MMC treatment in parental cells, but not in rodent FA‐like V‐H4 cells. Moreover, our data indicate that Rad51 foci formation is significantly delayed in these FA‐like cells in response to crosslinking agent. These findings provide evidence for an impairment of HR control in V‐H4 cells and emphasize the involvement of the FA pathway in HR‐mediated repair.
Cardiologic and neurologic findings in left ventricular hypertrabeculation/non‐compaction related to wall thickness, size and systolic function
Authors: Stöllberger Claudia , Finsterer Josef
Published: August 2004

Left ventricular hypertrabeculation/noncompaction (LVHT) is a rare cardiac abnormality, diagnosed echocardiographically when >3 left ventricular trabeculations are visible in one image plane apically to the papillary muscles and intertrabecular spaces are perfused from the ventricular cavity. In the majority of the cases, LVHT is associated with neuromuscular disorders (NMD). LVHT occurs in dilated as well as in normally sized ventricles, with or without systolic dysfunction and wall thickening. Aim of the study was to assess whether cardiologic and neurologic findings differ between patients according to echocardiographically determined left ventricular size, systolic function and wall thickness. In 77 patients (19 f, mean age 52 years) LVHT was diagnosed. LVHT was assessed as ‘dilative’ (enddiastolic diameter ≥60 mm and fractional shortening ≤25%) in 43 cases, in 18 patients as ‘hypertrophic’ (interventricular septum and posterior wall ≥12 mm and fractional shortening ≥26%) and in the remaining 16 patients as ‘normally‐dimensioned’. Dilative LVHT patients were older than hypertrophic or normally‐dimensioned LHVT patients. The prevalence of NMD was 63% in dilative LVHT, 67% in hypertrophic LVHT and 56% in normally‐dimensioned LVHT. LHVT is more frequently found in dilated than hypertrophic ventricles. NMD are equally frequent in dilative, hypertrophic and normally‐dimensioned LVHT. Cardiac abnormalities may progress with age.
Selective versus nonselective β‐adrenergic receptor blockade in chronic heart failure: differential effects on myocardial energy substrate utilization
Authors: Al‐Hesayen Abdul , Azevedo Eduardo R. , Floras John S. , Hollingshead Shauna , Lopaschuk Gary D. , Parker John D.
Published: August 2004

Background:

Non‐selective and selective β‐blockers have been shown to improve outcomes in chronic heart failure (CHF). Recent data suggests the non‐selective β‐blockers have a more favourable effect on outcomes than β1‐selective agents. We sought to examine the differential effects of non‐selective versus selective β‐blockade on myocardial substrate utilization in patients with CHF.

Methods and results:

Twenty‐two patients with CHF were randomised to the non‐selective β‐blocker carvedilol or the selective β‐blocker metoprolol (double‐blind). Measurement of hemodynamics, arterial and coronary sinus free fatty acid (FFA) and lactate levels, and cardiac norepinephrine spillover (CANESP) were made before and after 4 months of therapy. In the carvedilol group (n=11), there was a significant reduction in myocardial FFA uptake (0.12±0.02 to 0.1±0.02 mmol/l, P<0.03). By contrast, in the metoprolol group (n=11) there was no change in myocardial FFA extraction. Carvedilol therapy tended to increase myocardial lactate extraction (0.24±0.05 to 0.35±0.08 mmol/l, P=0.08) while metoprolol therapy resulted in a trend in the opposite direction (0.18±0.03 to 0.11±0.04 mmol/l, P=0.09). The change in lactate extraction in the carvedilol group was significantly different from that in the metoprolol group (+0.11±0.06 vs. −0.09±0.04 mmol/l, P<0.01). Carvedilol treatment caused a significant reduction in CANESP while metoprolol had a neutral effect (−95±27 vs. 25±42 pmol/min, carvedilol vs. metoprolol P<0.03).

Conclusion:

Carvedilol treatment caused a 20% reduction in myocardial free fatty acid extraction while metoprolol had a neutral effect. These differences are most probably related to the differential effects of these two agents on efferent cardiac sympathetic activity and may be relevant to the reported differential effects of these drugs on clinical outcomes.