bluuebunny/crossref_metadata_2025 huggingface dataset:
On the high‐density polyethylene extrusion: Numerical, analytical and experimental modeling
Authors: Mamalis A. G. , Spentzas K. N. , Kouzilos G. , Theodorakopoulos I. , Pantelelis N. G.
Published: September 2010

A three‐dimensional numerical model was developed to investigate the nonisothermal, non‐Newtonian polymer flow through a cone cylindrical die used in the HDPE (high‐density polyethylene) extrusion process. The numerical model was based on the computational fluid dynamics code COMSOL 3.4 the finite element method, and it was used to calculate pressure, flow, and temperature distributions in a cone cylindrical die used for industrial‐scale extrusion of an HDPE rod. The model also accounted for viscous heating. In addition, pressure and temperature data were derived using an analytical solution. The numerical approach agrees fairly well with the experimental data recorded during the extrusion process of the material. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:173–184, 2010; View this article online at wileyonlinelibrary. DOI 10.1002/adv.20185
Nanofilled polyethersulfone as matrix for continuous glass fibers composites: Mechanical properties and solvent resistance
Authors: Aurilia M. , Sorrentino L. , Sanguigno L. , Iannace S.
Published: September 2010

Polyethersulfone (PES) is high performance thermoplastic polymer; however, its applications are limited by the poor resistance to several classes of solvents. Fumed silica and expanded graphite nanoparticles were used to prepare nanofilled PES by a melt‐compounding technique with the view to improve the barrier properties. Solvent uptake at equilibrium and solvents resistance of nanofilled PES compounds were investigated by three different methodologies: (1) weight increase by methylene chloride absorption in a vapor‐saturated atmosphere, (2) solvent uptake of acetone at equilibrium, and (3) decay of storage modulus induced by acetone diffusion. The storage modulus decay was measured by means of dynamic mechanical analysis on samples immersed in an acetone bath. The collected data were fitted to an ad hoc model to calculate the diffusion coefficient. The produced nanofilled PES showed a significant improvement in barrier properties and considerable reduction in acetone uptake at equilibrium, in comparison with the neat PES. Nanofilled PES compounds were also used to produce continuous glass fiber composites by the film‐stacking manufacturing technique. The composites exhibited, by and large, improvements in flexural and shear strength. Their solvent resistance was evaluated by measuring the variation of mechanical properties after exposure to acetone for 1 and 5 days. These tests showed that the composites produced with the nanocomposite matrix did not exhibit higher solvent resistance than those prepared with neat PES, probably because of the deterioration of the fiber/nanocomposite‐matrix interfacial bond in the wet state. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:146–160, 2010; View this article online at wileyonlinelibrary. DOI 10.1002/adv.20187
A property‐based approach to the synthesis of material conservation networks with economic and environmental objectives
Authors: Ponce‐Ortega José María , Mosqueda‐Jiménez Francisco Waldemar , Serna‐González Medardo , Jiménez‐Gutiérrez Arturo , El‐Halwagi Mahmoud M.
Published: September 2010

This article presents a multiobjective optimization model for the recycle and reuse networks based on properties while accounting for the environmental implications of the discharged wastes using life‐cycle assessment. The economic objective function considers fresh sources and treatment costs, whereas the environmental objective function is measured through the eco‐indicator 99. The model considers constraints in the process sinks as well as in the environment based on stream properties such as pH, chemical oxygen demand, toxicity, density, and color, in addition to the composition of the waste streams. A global optimization procedure is developed by indirectly tackling properties through property operators and by segregating the process streams before treatment. Three examples are included, and the results show that it is possible to consider simultaneously the trade‐offs between the total annual costs and the overall environmental impact using the proposed methodology. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Generalized LIQUAC model for the single‐ and mixed‐solvent strong electrolyte systems
Authors: Li Mi‐Yi , Wang Li‐Sheng , Jiang Bo , Gmehling Jürgen
Published: September 2010

A generalized strong electrolyte LIQUAC model is presented to describe the vapor–liquid equilibria, osmotic coefficients, mean ion activity coefficients, and solid–liquid equilibria for the single‐ and mixed‐solvent electrolyte systems over the entire concentration range from infinite dilution to saturated solutions. An appropriate reference state for the ions was first applied to test the capability of the model in simultaneously describing the mean ion activity coefficients and the solubility of a salt in a binary solvent mixture. The influence of salt on the vapor–liquid equilibrium behavior is predicted with the new correlated parameters. The generalized activity coefficient formulations are presented through the investigation of thermodynamic properties and phase phenomena in the single‐ and mixed‐solvent electrolyte systems. This work is a continuous study for the LIQUAC activity coefficient model. A reliable representation of the single‐ and mixed‐solvent salt solutions is obtained. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Construction of an ab initio kinetic model for industrial ethane pyrolysis
Authors: Sun Wenjie , Saeys Mark
Published: September 2010

The industrial steam cracking of ethane was simulated using an ab initio kinetic model. The reaction network consists of 20 species and 150 reversible elementary reactions. The thermodynamic and kinetic parameters were obtained from ab initio CBS‐QB3 and W1U calculations and agree well with available experimental data. Predicted C2H6, C2H4, and H2 yields are within 5% of experimental data for the three sets of conditions tested. Though CH4 yields and outlet temperatures are particularly sensitive to the accuracy of the kinetic parameters, they are simulated with an accuracy of better than 10%. Larger deviations for the C3H6 and C2H2 yields are attributed to the limited size of the reaction network. The effect of total pressure on the rate coefficients was evaluated using Quantum Rice‐Ramsberger‐Kassel theory with the Modified Strong‐Collision approximation, and was found to be relatively minor for the reaction conditions tested. This study hence demonstrates the feasibility of simulating complex radical reactions using a predictive kinetic model derived from state‐of‐the‐art quantum chemical calculations. © 2010 American Institute of Chemical Engineers AIChE J, 2011
The effect of hydrogen peroxide‐induced oxidative stress on leukocytes depends on age and physical training in healthy human subjects carrying the same genotypes of antioxidant enzymes' gene polymorphisms
Authors: Miranda‐Vilela Ana Luisa , Alves Penha Cristina Z. , Akimoto Arthur K. , Pereira Luiz Carlos S. , Nazaré Klautau‐Guimarães Maria de , Grisolia Cesar K.
Published: September 2010

Objectives

Reactive oxygen species account for the background levels of oxidatively damaged DNA in normal tissues. Physical exercise increases oxygen consumption and can cause oxidative stress. This stress can also involve deficient antioxidant defenses, which can be influenced by certain genetic polymorphisms. Because regular exercise is a known inducer of antioxidant enzymes, the objective of this study was to compare, by comet assay, differences in the DNA damage between apparently healthy individuals and trained aerobic sportsmen carrying the same single nucleotide polymorphisms of manganese superoxide dismutase (Val9Ala), catalase (−21A/T), glutathione peroxidase 1 (Pro198Leu), before and after exposing leukocytes from peripheral blood to hydrogen peroxide (H2O2).

Methods

Athletes were compared with nonathletes after a situation that promotes reactive oxygen species increase (a race). Blood samples were submitted to genotyping and comet assay, and the athletes and nonathletes were paired according to their gender, age, and MnSOD, CAT, and GPx‐1 genotypes.

Results

For nonathletes, there was a positive correlation between H2O2 concentrations and DNA damage levels. For athletes, these correlations showed differences between sexes, indicating that running may impose higher oxidative stress on the DNA of women than of men. Significant differences appeared for nonathletes in the comparisons between younger and older age groups after treatment with H2O2 at 250 μM.

Conclusions

This suggests that, for individuals carrying the same genotypes of antioxidant enzymes' genes, the effect of H2O2‐induced oxidative stress depends mainly on age and physical training. It also suggests that aerobic physical training can reduce oxidative damages to DNA, preventing related diseases in older people. Am. J. Hum. Biol., 2010. © 2010 Wiley‐Liss, Inc.
Epidemiology of nonsyndromic conotruncal heart defects in Texas, 1999–2004
Authors: Long Jin , Ramadhani Tunu , Mitchell Laura E.
Published: September 2010

INTRODUCTION: Congenital heart defects (CHDs) are the most common structural birth defects, yet their etiology is poorly understood. As there is heterogeneity within the group of CHDs, epidemiologic studies often focus on subgroups, of conditions, such as conotruncal heart defects (CTDs). However, even within these subgroups there may be etiologic heterogeneity. The aim of the present study was to identify and compare maternal and infant characteristics associated with three CTDs: truncus arteriosus (TA), dextro‐transposition of the great arteries (d‐TGA), and tetralogy of Fallot (TOF). METHODS: Data for cases with nonsyndromic TA (n = 78), d‐TGA (n = 438), and TOF (n = 529) from the Texas Birth Defects Registry, 1999–2004, were used to estimate crude and adjusted prevalence ratios, separately for each condition, using Poisson regression. Polytomous logistic regression was used to determine whether the observed associations were similar across the two largest case groups (d‐TGA and TOF). RESULTS: In Texas, 1999–2004, the prevalence of nonsyndromic TA, d‐TGA, and TOF was 0.35, 1.98, and 2.40 per 10,000 live births, respectively. There was evidence of a significant linear increase in the risk of each condition with advancing maternal age (p < 0.01). Significant associations were observed for TA and maternal residence on the Texas‐Mexico border; d‐TGA and infant sex, maternal race/ethnicity, history of previous live birth, and birth year; and TOF and maternal race/ethnicity and education. Further, the associations with some, but not all, of the study variables were significantly different for d‐TGA and TOF. CONCLUSION: These findings add to our limited understanding of the epidemiology of CTDs. Birth Defects Research (Part A), 2010. © 2010 Wiley‐Liss, Inc.
Meta-analysis of intraoperative povidone–iodine application to prevent surgical-site infection
Authors: Fournel I , Tiv M , Soulias M , Hua C , Astruc K , Aho Glélé L S
Published: September 2010

Background

The effectiveness of intraoperative povidone–iodine (PVI) application in the reduction of surgical-site infection (SSI) remains controversial. This meta-analysis was performed to assess the effect of intraoperative PVI application compared with no antiseptic solution (saline or nothing) on the SSI rate.

Methods

The meta-analysis included randomized controlled trials that compared intraoperative PVI lavage with no PVI in patients undergoing surgery with SSI as the primary outcome. A fixed-effects or random-effects model was used as appropriate, and heterogeneity was assessed by the Cochran Q and the I2 value.

Results

Twenty-four randomized controlled trials totalling 5004 patients (2465 patients with PVI and 2539 patients without) were included: 15 in the main analysis and nine in the sensitivity analysis. The rate of SSI was 8·0 per cent in the PVI group and 13·4 per cent in the control group. Intraoperative PVI application significantly decreased the SSI rate (relative risk 0·58, 95 per cent confidence interval 0·40 to 0·83; P = 0·003) and consistent results were observed in subgroup analyses according to the method of PVI administration, its timing and the type of surgery.

Conclusion

The meta-analysis results suggested that the use of intraoperative PVI reduced rates of SSI.
Visual aesthetics in store environment and its moderating role on consumer intention
Authors: Vieira Valter Afonso
Published: September 2010

The paper goal is to answer the following questions: What are the factors of centrality of visual aesthetic design (CVSA) in store environment? What factor explains better the construct? Is there a relationship between CVSA and consumers' intentions, such as loyalty, satisfaction, minutes, item, and $ spent inside store? What is the moderating role of store visual aesthetic design on consumer intentions? The research design was a 2 × 2 design, between subjects, which we manipulated store arousal (high vs. low) and CVSA (high vs. low) in two studies. The findings supported the theory that there are three CVSA dimensions; that there is a positive relationship between CVSA and consumer satisfaction, loyalty, items bought, minutes visiting the store, and $ spent; and that high (vs. low) CVSA consumers were more discriminating in their intentions, when the environment had a high arousal. The original value is to support the notion that consumers also evaluate, beyond products, visual aesthetic components in retail and that it plays a moderating role on consumer intention.

Copyright © 2010 John Wiley & Sons, Ltd.
15N and 13C Group‐Selective Techniques Extend the Scope of STD NMR Detection of Weak Host–Guest Interactions and Ligand Screening
Authors: Kövér Katalin E. , Wéber Edit , Martinek Tamás A. , Monostori Éva , Batta Gyula
Published: September 2010

Saturation transfer difference (STD) is a valuable tool for studying the binding of small molecules to large biomolecules and for obtaining detailed information on the binding epitopes. Here, we demonstrate that the proposed 15N/13C variants of group‐selective, “GS‐STD” experiments provide a powerful approach to mapping the binding epitope of a ligand even in the absence of efficient spin diffusion within the target protein. Therefore, these experimental variants broaden the scope of STD studies to smaller and/or more‐dynamic targets. The STD spectra obtained in four different experimental setups (selective 1H STD, 15N GS‐STD, 13CAr and 13Caliphatic GS‐STD approaches) revealed that the signal‐intensity pattern of the difference spectra is affected by both the type and the spatial distribution of the excited “transmitter” atoms, as well as by the efficiency of the spin‐diffusion‐mediated magnetization transfer. The performance of the experiments is demonstrated on a system by using the lectin, galectin‐1 and its carbohydrate ligand, lactose.
Termolecular Kinetic Model for CO2‐Alkanolamine Reactions: An Overview
Authors: Vaidya P. D. , Kenig E. Y.
Published: September 2010

The CO2 reaction with alkanolamines has received considerable attention by both academia and industry. Commonly, the formation of the carbamate during the CO2 reaction with primary, secondary, and sterically hindered amines is described by a two‐step zwitterion mechanism. Alternatively, a single‐step termolecular reaction mechanism can also be used to govern carbamate formation. The experimental kinetic data for several amine‐based solvents are consistent with this mechanism, and it can satisfactorily explain fractional‐order and higher‐order kinetics. However, up to now, the termolecular reaction mechanism has not been properly discussed. Here, this mechanism is described in detail, a simple procedure to estimate the kinetic parameters is outlined, and the termolecular reaction kinetics for various systems comprising individual and mixed amines is reviewed.
Experimental Investigation on the Characteristics of Polyethylene Glycol/Cement Composites as Thermal Energy Storage Materials
Authors: Li H. , Fang G.‐Y.
Published: September 2010

The polyethylene glycol/cement composites as thermal energy storage materials were prepared by blending polyethylene glycol and cement. In composite materials, polyethylene glycol (PEG) is used as the phase change material for thermal energy storage and cement acts as the supporting material. A Fourier transformation infrared spectroscope (FT‐IR), x‐ray diffractometer (XRD), and scanning electronic microscope (SEM) were used to determine the chemical structure, the crystalloid phase, and microstructure of the polyethylene glycol/cement composites, respectively. The thermal properties and thermal stability were investigated by a differential scanning calorimeter (DSC) and a thermogravimetry analyzer (TGA). The SEM results showed that the polyethylene glycol was well dispersed in the porous network of the cement.
Vapor Pressure of Water in Mixtures with Hydrophilic Ionic Liquids – A Contribution to the Design of Processes for Drying of Gases by Absorption in Ionic Liquids
Authors: Heym F. , Haber J. , Korth W. , Etzold B. J. M. , Jess A.
Published: September 2010

The low water vapor pressures of mixtures of water with the ionic liquids (ILs), [EMIM][EtSO4] and [BEIM][EtSO4], indicate that a process of gas dehydration by absorption in ILs might be an alternative to the classical absorption process with triethylene glycol (TEG). The activity coefficient for an infinite dilution of water in the IL (xIL → 1), which should be low for efficient dehydration, is only about 0.2 for [EMIM][EtSO4] compared to 0.6 for triethylene glycol. In contrast to TEG, losses by evaporation are excluded with ILs as solvents, because they have a negligible vapor pressure. The number of separation stages needed for the absorption in the IL and for the subsequent regeneration of the water‐loaded IL is small, about six and eight, respectively. IL regeneration can be achieved by distillation of water out of the IL (e.g., at 120 °C) and stripping with ambient air, which is not possible in the case of TEG (chemical attack by O2).
Thermodynamic Studies of Chromium Adsorption on Iron Species Generated by Electrocoagulation
Authors: Parga J. R. , Vazquez V. , Gonzalez G. , Cisneros M. M.
Published: September 2010

The protection of the global environment and in particular, the provision of a sustainable source of clean water is a necessity for human survival. Specifically, large quantities of chromium containing compounds are being discharged into the environment. This study has been carried out to determine the feasibility of chromium adsorption on iron species by an Electrocoagulation (EC) process using the Langmuir Isotherm.

The full potential of EC with air injection as an alternative wastewater treatment technique to remove chromium from well water shows more than 99 % removal without the addition of any chemical reagents. In this study, X‐Ray Diffraction, Scanning Electron Microscopy, Mössbauer Spectroscopy and Fourier Transform Infrared Spectroscopy are used to characterize the solid products that reveal the expected crystalline iron oxides, i.e., lepidocrocite, magnetite, gohetite, and iron oxide.
Some common misunderstandings in chemometrics
Authors: Kjeldahl Karin , Bro Rasmus
Published: September 2010

This paper describes a number of issues and tools in practical chemometric data analysis that are often either misunderstood or misused. Deciding what are relevant samples and variables, (mis‐)use of common model diagnostics, and interpretational issues are addressed in relation to component models such as PCA and PLS models. Along with simple misunderstandings, the use of chemometric software packages may contribute to the mistakes if not used critically, and it is thus a main conclusion that good data analysis practice requires the analyst to take responsibility and do what is relevant for the given purpose. Copyright © 2010 John Wiley & Sons, Ltd.
Hydroxyl Radical Reactions with Adenine: Reactant Complexes, Transition States, and Product Complexes
Authors: Cheng Qianyi , Gu Jiande , Compaan Katherine R. , Schaefer Henry F.
Published: September 2010

In order to address problems such as aging, cell death, and cancer, it is important to understand the mechanisms behind reactions causing DNA damage. One specific reaction implicated in DNA oxidative damage is hydroxyl free‐radical attack on adenine (A) and other nucleic acid bases. The adenine reaction has been studied experimentally, but there are few theoretical results. In the present study, adenine dehydrogenation at various sites, and the potential‐energy surfaces for these reactions, are investigated theoretically. Four reactant complexes [A⋅⋅⋅OH]. have been found, with binding energies relative to A+OH. of 32.8, 11.4, 10.7, and 10.1 kcal mol−1. These four reactant complexes lead to six transition states, which in turn lie +4.3, −5.4, (−3.7 and +0.8), and (−2.3 and +0.8) kcal mol−1 below A+OH., respectively. Thus the lowest lying [A⋅⋅⋅OH]. complex faces the highest local barrier to formation of the product (AH).+H2O. Between the transition states and the products lie six product complexes. Adopting the same order as the reactant complexes, the product complexes [(AH)⋅⋅⋅H2O]. lie at −10.9, −22.4, (−24.2 and −18.7), and (−20.5 and −17.5) kcal mol−1, respectively, again relative to separated A+OH.. All six A+OH. → (AH).+H2O pathways are exothermic, by −0.3, −14.7, (−17.4 and −7.8), and (−13.7 and −7.8) kcal mol−1, respectively. The transition state for dehydrogenation at N6 lies at the lowest energy (−5.4 kcal mol−1 relative to A+OH.), and thus reaction is likely to occur at this site. This theoretical prediction dovetails with the observed high reactivity of OH radicals with the NH2 group of aromatic amines. However, the high barrier (37.1 kcal mol−1) for reaction at the C8 site makes C8 dehydrogenation unlikely. This last result is consistent with experimental observation of the imidazole ring opening upon OH radical addition to C8. In addition, TD‐DFT computed electronic transitions of the N6 product around 420 nm confirm that this is the most likely site for hydrogen abstraction by hydroxyl radical.
Construction of N‐Glycan Microarrays by Using Modular Synthesis and On‐Chip Nanoscale Enzymatic Glycosylation
Authors: Serna Sonia , Etxebarria Juan , Ruiz Nerea , Martin‐Lomas Manuel , Reichardt Niels‐Christian
Published: September 2010

An effective chemoenzymatic strategy is reported that has allowed the construction, for the first time, of a focused microarray of synthetic N‐glycans. Based on modular approaches, a variety of N‐glycan core structures have been chemically synthesized and covalently immobilized on a glass surface. The printed structures were then enzymatically diversified by the action of three different glycosyltransferases in nanodroplets placed on top of individual spots of the microarray by a printing robot. Conversion was followed by lectin binding specific for the terminal sugars. This enzymatic extension of surface‐bound ligands in nanodroplets reduces the amount of precious glycosyltransferases needed by seven orders of magnitude relative to reactions carried out in the solution phase. Moreover, only those ligands that have been shown to be substrates to a specific glycosyltransferase can be individually chosen for elongation on the array. The methodology described here, combining focused modular synthesis and nanoscale on‐chip enzymatic elongation, could open the way for the much needed rapid construction of large synthetic glycan arrays.
New Boryl Radicals Derived from N‐Heteroaryl Boranes: Generation and Reactivity
Authors: Lalevée Jacques , Blanchard Nicolas , Tehfe Mohamad‐Ali , Chany Anne‐Caroline , Fouassier Jean‐Pierre
Published: September 2010

Recently, boryl radicals have been the subject of revived interest. These structures were generated by hydrogen‐abstraction reactions from the corresponding boranes (i.e., from amine or phosphine boranes). However, the classical issue remains their high BH bond‐dissociation energy (BDE), thereby preventing a very efficient hydrogen‐abstraction process. In the present paper, new N‐heteroaryl boranes that exhibiting low BH BDE are presented; excellent hydrogen‐transfer properties have been found. Both the generation and the reactivity of the associated boryl radicals have been investigated through their direct observation in laser flash photolysis. The boryl radical interactions with double bonds, oxygen, oxidizing agent, and alkyl halides have been studied. Some selected applications of N‐heteroaryl boryl radicals as new polymerization‐initiating structures are proposed to evidence their high intrinsic reactivity.
Chemo‐Genetic Optimization of DNA Recognition by Metallodrugs using a Presenter‐Protein Strategy
Authors: Zimbron Jeremy M. , Sardo Alessia , Heinisch Tillmann , Wohlschlager Therese , Gradinaru Julieta , Massa Claudia , Schirmer Tilman , Creus Marc , Ward Thomas R.
Published: September 2010

The mode of action of precious metal anticancer metallodrugs is generally believed to involve DNA as a target. However, the poor specificity of such drugs often requires high doses and leads to undesirable side‐effects. With the aim of improving the specificity of a ruthenium piano‐stool complex towards DNA, we employed a presenter protein strategy based on the biotin–avidin technology. Guided by the X‐ray structure of the assembly of streptavidin and a biotinylated piano‐stool, we explored the formation of metallodrug‐mediated ternary complexes with the presenter protein and DNA. The assemblies bound more strongly to telomere G‐quadruplexes than to double‐stranded DNA; chemo‐genetic modifications (varying the complex or mutating the protein) modulated binding to these targets. We suggest that rational targeting of small molecules by presenter proteins could be exploited to bind metallodrugs to preferred macromolecular targets.
Magnetothermal Studies of a Series of Coordination Clusters Built from Ferromagnetically Coupled {MnII4MnIII6} Supertetrahedral Units
Authors: Nayak Sanjit , Evangelisti Marco , Powell Annie K. , Reedijk Jan
Published: September 2010

Three high‐nuclearity mixed valence manganeseII/III coordination clusters, have been synthesised, that is, [MnIII6MnII4(μ3‐O)4(HL1)6(μ3‐N3)3(μ3‐Br)(Br)](N3)0.7/(Br)0.3⋅3 MeCN⋅2 MeOH (1) (H3L1=3‐methylpentan‐1,3,5‐triol), [MnIII11MnII6(μ4‐O)8(μ3‐Cl)4(μ,μ3‐O2CMe)2(μ,μ‐L2)10Cl2.34(O2CMe)0.66(py)3(MeCN)2]⋅7 MeCN (2) (H2L2=2,2‐dimethyl‐1,3‐propanediol and py is pyridine), and [MnIII12MnII7(μ4‐O)8(μ3‐η1N3)8(HL3)12(MeCN)6]Cl2⋅10 MeOH ⋅MeCN (3) (H3L3=2,6‐bis(hydroxymethyl)‐4‐methylphenol) with high ground‐spin states, S=22, 28±1, and 83/2, respectively; their magnetothermal properties have been studied. The three compounds are based on a common supertetrahedral building block as seen in the Mn10 cluster. This fundamental magnetic unit is made up of a tetrahedron of MnII ions with six MnIII ions placed midway along each edge giving an inscribed octahedron. Thus, the fundamental building unit as represented by compound 1 can be described as a Mn10 supertetrahedron. Compounds 2 and 3 correspond to two such units joined by a common edge or vertex, respectively, resulting in Mn17 and Mn19 coordination clusters. Magnetothermal studies reveal that all three compounds show interesting long‐range magnetic ordering at low temperature, originating from negligible magnetic anisotropy of the compounds; compound 2 shows the largest magnetocaloric effect among the three compounds. This is as expected and can be attributed to the presence of a small magnetic anisotropy, and low‐lying excited states in compound 2.
Effect of dialysate temperature on intradialytic hypotension
Authors: Korkor Adel B. , Bretzmann Christine M. , Eastwood Daniel
Published: September 2010

BACKGROUND

The aim of the study was to determine whether lowering the dialysate temperature in hemodialysis patients would result in a decreased frequency of intradialytic hypotension.

METHODS

Dialysate temperature was lowered by 0.5°C increments in seven hypotension‐prone hemodialysis patients. The primary outcomes, measured over 12 weeks, included systolic blood pressure less than 90 mmHg, an interruption in ultrafiltration due to hypotension, and whether target fluid loss was achieved.

RESULTS

Dialysate temperature was lowered by a total of 0.5°C in four patients and 1.0°C in three patients. Results are presented as odds ratios for every 0.5° decrease in dialysate temperature. The odds of systolic blood pressure dropping to below 90 mmHg and the odds that ultrafiltration would be interrupted due to hypotension were lowered to 0.30 and 0.91 times the odds with a higher dialysate temperature (p < .0001 and p < .0074, respectively). The odds of achieving target fluid loss were 3.60 times greater with a lower dialysate temperature (p < .0001).

DISCUSSION

A reduction in dialysate temperature by as little as 0.5–1.0°C had a significant effect on intradialytic hypotension in this patient population. We feel that this represents a practical and effective method for managing intradialytic hypotension in hypotension‐prone dialysis patients.
The potential use of complex derivatization procedures in comprehensive HPLC‐MS/MS detection of anabolic steroids
Authors: Baranov Pavel A. , Appolonova Svetlana A. , Rodchenkov Grigory M.
Published: September 2010

The use of two separate derivatization procedures with the formation of oxime (hydroxyl ammonium pretreatment) and picolinoyl (mixed anhydride method) derivates of anabolic steroids following HPLC‐MS/MS analysis was proposed. The main product ions of obtained derivatives for 21 anabolic steroids were evaluated and fragmentation pathways were compared.

The analysis of MS/MS spectra for underivatized steroids versus oxime or picolinoyl derivatives showed that in case of analytes containing conjugated double bonds in sterane core all of the observed MS/MS spectra contained abundant product ions of diagnostic value. The implementation of derivatization procedures to such compounds is useful for upgrading sensitivity or selectivity of the evaluated method. On the other hand, MS/MS spectra of underivatized and oxime analytes without conjugated double bonds in sterane core produce spectra with large amounts of low abundant product ions. Picolinoyl derivatives formation leads to highly specific spectra with product ions of diagnostic value coupled with sensitive and selective analysis at the same time. The intra‐ and inter‐group comparison analysis revealed that fragmentation pathways for underivatized steroids and correspondent oxime derivatives are similar.

The obtained oxime and picolinoyl derivatives provided 10–15 times higher ESI response in the HPLC‐ESI‐MS‐selected reaction monitoring (SRM) when compared to those of underivatized molecules in positive HPLC‐ESI‐MS mode.

Due to the laborious sample preparation we suggest to use the performed strategy for confirmation analysis purposes, metabolic studies or while the identification of new steroids or steroid‐like substances. Copyright © 2010 John Wiley & Sons, Ltd.
Influence of olive crushing methods on the yields and oil characteristics
Authors: Preziuso Serena Maria , Di Serio Maria Gabriella , Biasone Alessandro , Vito Raffaella , Mucciarella Maria Regina , Di Giovacchino Luciano
Published: September 2010

In the last years, metallic crushers substituted granite stone mill with some variations in the organoleptic oil characteristics. To control the influence of the crushing method on the yield and oil quality, the olive pastes were obtained using three different ways: (i) new metallic crusher at mobile knives; (ii) granite stone mill; (iii) double olive crushing by the metallic crusher and the granite stone mill. With the aim to ascertain the useful use of a new metallic crusher (at mobile knives), experimental tests were carried out in an industrial oil mill. This oil mill is equipped by a centrifugal decanter generating two oil flows: first and second extraction (recovery) oils. The results showed that the yields obtained by different methods were satisfactory. No statistically significant differences have been observed in terms of oil yield and quality when different crushing devices were used. All first extracted oils are extra virgin with similar organoleptic characteristics, especially for the fruity intensity and for the bitter and pungent taste, as confirmed by the composition of volatile substances and the content of phenolic oil compounds. The recovery oils (second extraction oils) showed, in contrast to first extraction oils, a more intense green colour and a higher content of total phenols.

Practical applications: Processing of sound olives with the right ripening grade and good quality allows to easily obtain an extra virgin olive oil, with commercial qualitative parameters according to the European Union requirements. However, different olive crushing systems affect the concentrations of some compounds responsible of aroma and taste (phenolic compounds). The use of the more violent metallic crushers facilitates obtaining oils with total phenol content higher than when using a stone mill. Here we used a particular metallic crusher (at knives) that, however, is suitable to replace the granite stone mill when a less pungent and bitter oil is required.
Intestinal digestion of fish oils and ω‐3 concentrates under in vitro conditions
Authors: Martin Diana , Nieto‐Fuentes Juan A. , Señoráns Francisco J. , Reglero Guillermo , Soler‐Rivas Cristina
Published: September 2010

A comparative study of the in vitro bioaccesibility of ω‐3‐oils (salmon oil, SO; tuna oil, TO; enriched‐ω‐3 oil as triacylglycerols (TAGs), ω‐3‐TAG; and enriched‐ω‐3 oil as ethyl esters (EEs), ω‐3‐EE) was performed after treatment with pancreatin (pancreatic lipase as major lipolytic enzyme) at pH 7.5. Aliquots were taken at different times of digestion for analyzing the evolution of lipid products. The micellar phase (MP) formed at 120 min of digestion was isolated, its total lipid content was extracted and its composition in lipid products was analyzed. The rate of hydrolysis of ω‐3‐TAG concentrates was continuous throughout the time of reaction (51% hydrolysis of TAGs at 120 min), whereas the digestion of SO and TO was initially faster but stopped after 10 min of reaction (35 and 38% hydrolysis of TAGs at 120 min of SO and TO, respectively). A poor hydrolysis of EEs took place for the ω‐3‐EE oil (around 7% hydrolysis of EEs at 120 min). The MP of ω‐3‐TAG oil, SO, and TO mainly consisted of free fatty acids (FFAs) and MAGs. The MP from digested ω‐3‐EE oil consisted of FFAs and undigested EEs. Therefore, the highest degree of hydrolysis and inclusion of lipid products in the micellar structure was found for the ω‐3‐TAG oil, but compared to fish oils long times of digestion were required. This experience also shows for the first time the MP composition from ω‐3‐concentrates in the form of EEs.

Practical applications: Commercial ω‐3 sources can be found as purified fish oil or concentrates in the form of TAGs, FFAs, and EEs. Despite differences exist regarding their intestinal metabolism, there is lack of information about the specific composition in lipolytic products of the absorbable fraction (MP) from ω‐3‐TAG or ω‐3‐EE concentrates. This comparative study showed that (i) the in vitro bioaccesibility of ω‐3‐polyunsaturated fatty acid (PUFA) seems to be better as ω‐3‐TAG concentrates than purified fish oils, but after long times of digestion; and (ii) the in vitro hydrolysis of ω‐3‐PUFA as EEs seems to be poor, at least after the activity of the major lipolytic enzyme of pancreatin, namely pancreatic lipase. Furthermore, the inclusion of EEs within micellar structures seems to be limited. These results contribute to the knowledge of the intestinal lipolysis of ω‐3 sources by showing the composition of the MP on lipid products for the first time.
Facile Synthesis of Dihydroquinoline‐Fused Canthines by Intramolecular Aza‐Diels–Alder Reaction
Authors: Hutait Samiran , Singh Virender , Batra Sanjay
Published: September 2010

The synthesis of dihydroquinoline‐fused canthines by intramolecular aza‐Diels–Alder reaction between N‐prenylated 1‐formyl‐9H‐β‐carbolines and substituted anilines in the presence of a Lewis acid, followed by oxidation, is described. Additionally, it has been found that the N‐protected aldehyde in the presence of a suitable catalyst [ZnBr2 or Yb(OTf)3] undergoes intramolecular carbonyl–ene reaction in a diastereoselective fashion to afford the syn or anti isomer of a new canthine derivative.
DNA‐dependent protein kinase catalytic subunit mediates T‐cell loss in rheumatoid arthritis
Authors: Shao Lan , Goronzy Jörg J. , Weyand Cornelia M.
Published: September 2010

In the autoimmune syndrome rheumatoid arthritis (RA), T cells and T‐cell precursors have age‐inappropriate shortening of telomeres and accumulate deoxyribonucleic acid (DNA) double strand breaks. Whether damaged DNA elicits DNA repair activity and how this affects T‐cell function and survival is unknown. Here, we report that naïve and resting T cells from RA patients are susceptible to undergo apoptosis. In such T cells, unrepaired DNA stimulates a p53‐ataxia telangiectasia mutated‐independent pathway involving the non‐homologous‐end‐joining protein DNA‐protein kinase catalytic subunit (DNA‐PKcs). Upregulation of DNA‐PKcs transcription, protein expression and phosphorylation in RA T cells co‐occurs with diminished expression of the Ku70/80 heterodimer, limiting DNA repair capacity. Inhibition of DNA‐PKcs kinase activity or gene silencing of DNA‐PKcs protects RA T cells from apoptosis. DNA‐PKcs induces T‐cell death by activating the JNK pathway and upregulating the apoptogenic BH3‐only proteins Bim and Bmf. In essence, in RA, the DNA‐PKcs‐JNK‐Bim/Bmf axis transmits genotoxic stress into shortened survival of naïve resting T cells, imposing chronic proliferative turnover of the immune system and premature immunosenescence. Therapeutic blockade of the DNA‐PK‐dependent cell‐death machinery may rejuvenate the immune system in RA.
Numerical study on the effects of floodplain vegetation on river planform style
Authors: Crosato Alessandra , Saleh May Samir
Published: September 2010

The effects of floodplain vegetation on river planform have been investigated for a medium‐sized river using a 2D morphodynamic model with submodels for flow resistance and plant colonization. The flow resistance was divided into a resistance exerted by the soil and a resistance exerted by the plants. In this way it was possible to reproduce both the decrease in bed shear stress, reducing the sediment transport capacity of the flow within the plants, and the increase in hydraulic resistance, reducing the flow velocities. Colonization by plants was obtained by instantaneously assigning vegetation to the areas that became dry at low water stages. This colonization presents a step forward in the modelling of bank accretion. Bank erosion was related to bed degradation at adjacent wet cells. Bank advance and retreat were reproduced as drying and wetting of the computational cells at the channel margins. The model was applied to a hypothetical case with the same characteristics as the Allier River (France). The river was allowed to develop its own geometry starting from a straight, uniform, channel. Different vegetation densities produced different planforms. With bare floodplains, the river always developed a braided planform, even if the discharge was constant and below bankfull. With the highest vegetation density (grass) the flow concentrated in a single channel and formed incipient meanders. Lower vegetation density (pioneer vegetation) led to a transitional planform, with a low degree of braiding and distinguishable incipient meanders. The results comply with flume experiments and field observations reported in the literature.
Numerical studies of the fingering phenomena for the thin film equation
Authors: Li Yibao , Lee Hyun Geun , Yoon Daeki , Hwang Woonjae , Shin Suyeon , Ha Youngsoo , Kim Junseok
Published: September 2010

We present a new interpretation of the fingering phenomena of the thin liquid film layer through numerical investigations. The governing partial differential equation is ht + (h2−h3)x = −∇·(h3∇Δh), which arises in the context of thin liquid films driven by a thermal gradient with a counteracting gravitational force, where h = h(x, y, t) is the liquid film height. A robust and accurate finite difference method is developed for the thin liquid film equation. For the advection part (h2−h3)x, we use an implicit essentially non‐oscillatory (ENO)‐type scheme and get a good stability property. For the diffusion part −∇·(h3∇Δh), we use an implicit Euler's method. The resulting nonlinear discrete system is solved by an efficient nonlinear multigrid method. Numerical experiments indicate that higher the film thickness, the faster the film front evolves. The concave front has higher film thickness than the convex front. Therefore, the concave front has higher speed than the convex front and this leads to the fingering phenomena. Copyright © 2010 John Wiley & Sons, Ltd.
Effects of heat and mass transfer on peristaltic flow of Williamson fluid in a non‐uniform channel with slip conditions
Authors: Hayat T. , Hina S.
Published: September 2010

The combined influence of heat and mass transfer has been explored in a study of peristaltic transport of magnetohydrodynamic Williamson fluid in a non‐uniform channel with flexible walls. The slip conditions are paid due attention and long wavelength and small Reynolds number assumptions are adopted in the problem formulation. The obtained results are valid for small Weissenberg number. A detailed study of involved key parameters in the obtained solutions is made by the sketched graphs. Copyright © 2010 John Wiley & Sons, Ltd.
Microglia in the degenerating brain are capable of phagocytosis of beads and of apoptotic cells, but do not efficiently remove PrPSc, even upon LPS stimulation
Authors: Hughes Martina M. , Field Robert H. , Perry V. Hugh , Murray Carol L. , Cunningham Colm
Published: September 2010

Despite the phagocytic machinery available to microglia the aberrant amyloid proteins produced during Alzheimer's and prion disease, amyloid‐β and PrPSc, are inefficiently cleared. We have shown that microglia in the ME7 model of prion disease show morphological evidence of activation, synthesize low levels of pro‐inflammatory cytokines and are primed to produce exaggerated responses to subsequent inflammatory challenges. Whether these microglia engage in significant phagocytic activity in the disease per se, or upon subsequent inflammatory challenge is not clear. In the present study we show transcriptional activation of a large number of scavenger receptors (SRs), matrix metalloproteinases (MMPs), oxidative enzymes, and cathepsins in ME7 animals. Hippocampally‐injected inert latex beads (6 μm) are efficiently phagocytosed by microglia of ME7 prion‐diseased animals, but not by microglia in normal animals. Stimulation of ME7 animals with systemic bacterial endotoxin (lipopolysaccharide, LPS) induced further increases in SR‐A2, MMP3, and urokinase plasminogen activator receptor (uPAR) but decreased, or did not alter, transcription of most phagocytosis‐related genes examined and did not enhance clearance of deposited PrPSc. Furthermore, intracerebral injection with LPS (0.5 μg) induced marked microglial production of IL‐1β, robust cellular infiltration and marked apoptosis but also did not induce further clearance of PrPSc. These data indicate that microglia in the prion‐diseased brain are capable of phagocytosis per se, but show limited efficacy in removing PrPSc even upon marked escalation of CNS inflammation. Furthermore, microglia/macrophages remain IL‐1β‐negative during phagocytosis of apoptotic cells. The data demonstrate that phagocytic activity and pro‐inflammatory microglial phenotype do not necessarily correlate. © 2010 Wiley‐Liss, Inc.
The MAP3K TAK1: A Chock Block to Liver Cancer Formation
Authors: Malato Yann , Willenbring Holger
Published: September 2010

Abstract

TGF-β-activated kinase 1 (TAK1) is a MAP3K family member that activates NF-κB and JNK via Toll-like receptors and the receptors for IL-1, TNF-α, and TGF-β. Because the TAK1 downstream molecules NF-κB and JNK have opposite effects on cell death and carcinogenesis, the role of TAK1 in the liver is unpredictable. To address this issue, we generated hepatocyte-specific

Tak1

-deficient (

Tak1ΔHEP

) mice. The

Tak1ΔHEP

mice displayed spontaneous hepatocyte death, compensatory proliferation, inflammatory cell infiltration, and perisinusoidal fibrosis at age 1 month. Older

Tak1ΔHEP

mice developed multiple cancer nodules characterized by increased expression of fetal liver genes including α-fetoprotein. Cultures of primary hepatocytes deficient in

Tak1

exhibited spontaneous cell death that was further increased in response to TNF-α. TNF-α increased caspase-3 activity but activated neither NF-κB nor JNK in

Tak1

-deficient hepatocytes. Genetic abrogation of TNF receptor type I (TNFRI) in

Tak1ΔHEP

mice reduced liver damage, inflammation, and fibrosis compared with unmodified

Tak1ΔHEP

mice. In conclusion, hepatocyte-specific deletion of TAK1 in mice resulted in spontaneous hepatocyte death, inflammation, fibrosis, and carcinogenesis that was partially mediated by TNFR signaling, indicating that TAK1 is an essential component for cellular homeostasis in the liver.

The MAP3-kinase TGF-β-activated kinase 1 (TAK1) critically modulates innate and adaptive immune responses and connects cytokine stimulation with activation of inflammatory signaling pathways. Here, we report that conditional ablation of TAK1 in liver parenchymal cells (hepatocytes and cholangiocytes) causes hepatocyte dysplasia and early-onset hepatocarcinogenesis, coinciding with biliary ductopenia and cholestasis. TAK1-mediated cancer suppression is exerted through activating NF-κB in response to tumor necrosis factor (TNF) and through preventing Caspase-3-dependent hepatocyte and cholangiocyte apoptosis. Moreover, TAK1 suppresses a procarcinogenic and pronecrotic pathway, which depends on NF-κB-independent functions of the IκB-kinase (IKK)-subunit NF-κB essential modulator (NEMO). Therefore, TAK1 serves as a gatekeeper for a protumorigenic, NF-κB-independent function of NEMO in parenchymal liver cells.
The Recellularized Liver Matrix: A Novel Way of Transplantation?
Authors: Baeck Christer , Streetz Konrad
Published: September 2010

Abstract

Orthotopic liver transplantation is the only available treatment for severe liver failure, but it is currently limited by organ shortage. One technical challenge that has thus far limited the development of a tissue-engineered liver graft is oxygen and nutrient transport. Here we demonstrate a novel approach to generate transplantable liver grafts using decellularized liver matrix. The decellularization process preserves the structural and functional characteristics of the native microvascular network, allowing efficient recellularization of the liver matrix with adult hepatocytes and subsequent perfusion for in vitro culture. The recellularized graft supports liver-specific function including albumin secretion, urea synthesis and cytochrome P450 expression at comparable levels to normal liver in vitro. The recellularized liver grafts can be transplanted into rats, supporting hepatocyte survival and function with minimal ischemic damage. These results provide a proof of principle for the generation of a transplantable liver graft as a potential treatment for liver disease.