bluuebunny/crossref_metadata_2025_split huggingface dataset:
Children and adults are differentially affected by presentation modality in the DRM paradigm
Authors: Khanna Maya M. , Cortese Michael J. 
Published: September 2008

AbstractUsing the Deese–Roediger–McDermott (DRM) method for free recall, we examined mode of list presentation and association type in 8–9 year old children and adults. Participants verbally recalled lists of associates that were presented orally (Experiment 1) or visually (Experiment 2). Lists consisted of semantic associates (e.g. hound, puppy, etc.), phonological associates (e.g. log, dot, etc.) and both semantic and phonological associates (e.g. hound, dot, etc.) to a nonpresented lure word (e.g. dog). Interestingly, the ratio of false to true recall was higher in children than adults only when lists were presented orally. These results suggest that children rely more on sublexical information or item‐specific information than adults when reading lists, and, thus, are less likely to activate the critical lure via lexical associations. Furthermore, these results suggest that information processing differences at encoding between children and adults need to be taken into account when interpreting free recall studies. Copyright © 2008 John Wiley & Sons, Ltd.
Exploiting Non‐Covalent Interactions in Synthesis: Macrocyclization Employing Amide‐Based Auxiliaries
Authors: El‐Azizi Yassir , Zakarian Joseph E. , Bouillerand Lisa , Schmitzer Andreea R. , Collins Shawn K. 
Published: September 2008

AbstractEfficient macrocyclic olefin and en‐yne metathesis can be conducted employing benzyl ester auxiliaries that engage in quadrupolar interactions. The use of amide linkers in place of esters results in higher overall yields. Computational studies suggest that amide auxiliaries stabilize conformers conducive to macrocyclization over 22 times more efficiently than an ester linkage. Molecular modelling studies also suggest a preference for engaging in quadrupolar interaction for the amide auxiliaries, in contrast to the lone‐pair (lp):π interactions predicted for ester‐based auxiliaries.
Selective Hydrogen Oxidation Catalysts via Genetic Algorithms
Authors: Beckers Jurriaan , Clerc Frédèric , Blank Jan Hendrik , Rothenberg Gadi 
Published: September 2008

AbstractSolid “oxygen reservoirs,” such as doped ceria, can be successfully applied in a novel process for the oxidative dehydrogenation of propane. The ceria lattice oxygen selectively burns hydrogen from the dehydrogenation mixture at 550 °C. This gives three key advantages: it shifts the dehydrogenation equilibrium to the desired product side, generates heat in situ, which aids the endothermic dehydrogenation, and simplifies product separation. We have applied a genetic algorithm to screen doped cerias for their performance in the selective hydrogen oxidation. Three generations of doped ceria catalysts (61 catalysts in total), were synthesised. Dopants were chosen from a set of 26 elements, and with a maximum of two dopants per catalyst, at five different concentrations. The catalyst performance (activity and selectivity), is expressed by a fitness value. Each generation shows a higher average fitness value. The dopant type has a large effect on the catalyst fitness. We identified six dopant atoms which lead to selective hydrogen combustion catalysts, namely bismuth (Bi), chromium (Cr), copper (Cu), potassium (K), manganese (Mn), lead (Pb) and tin (Sn) (“good” dopants). Analysis of the effect of electronegativity, ionic radius and dopant concentration shows that most elements yielding a high fitness have electronegativities ranging from 1.5–1.9. Generally, the properties of catalysts containing two dopants can be predicted from the behaviour of singly doped ones. Synergy does occur for certain copper‐, iron‐ and platinum‐containing catalysts. The addition of calcium (Ca) or magnesium (Mg) to copper‐doped catalysts doubles the activity, and the selectivity of iron doped catalysts can be improved by adding chromium (Cr), manganese (Mn) or zirconium (Zr). Importantly, the doped cerias show a high stability in the redox cycling, much higher than that of supported oxides. A Cr‐ and Zr‐doped catalyst (Ce0.90Cr0.05Zr0.05O2) was highly selective and active over 250 redox cycles (a total of 148 h on stream), with no phase segregation or change in particle size.
Optimizing the rotated arc mixer
Authors: Singh Mrityunjay K. , Anderson Patrick D. , Speetjens Michel F. M. , Meijer Han E. H. 
Published: September 2008

AbstractUsing the mapping method an efficient methodology is developed for mixing analysis in the rotated arc mixer (RAM). The large parameter space of the RAM leads to numerous situations to be analyzed to achieve best mixing, and hence, it is indeed a challenging task to fully optimize the RAM. Two flow models are used to study mixing: one based on the full three‐dimensional (3‐D) flow field, and a second one based on a simplified 2.5‐D model, where an analytical solution is used for transverse velocity components in combination with a Poiseuille profile for the axial velocity component. Detailed 3‐D velocity field analyses reveal locally significant deviations from the Poiseuille profile e.g., presence of back‐flow, but only minimal differences in mixing performance is found using both flow models (3‐ and 2.5‐D) in the RAM designs that are candidates for accomplishing chaotic mixing. Despite the computational advantage of the 2.5‐D approach over the 3‐D approach, it is still cumbersome to analyze mixing for large number of designs using techniques based on particle tracking, e.g., Poincaré sections, dye traces, stretching distributions. Therefore, in this respect the mapping method provides an engineering tool able to tackle this optimization problem in an efficient way. On the basis of mixing evaluations, both in qualitative and quantitative sense, for the whole range of parameter space, the optimum set of design and kinematical parameters in the RAM is obtained to accomplish the best mixing. © 2008 American Institute of Chemical Engineers AIChE J, 2008
An adaptive direct quadrature method of moment for population balance equations
Authors: Su Junwei , Gu Zhaolin , Li Yun , Feng Shiyu , Xu X. Yun 
Published: September 2008

AbstractQuadrature method of moments (QMOM) and direct quadrature method of moments (DQMOM) for population balance equations (PBE) have been shown to be accurate and computationally efficient for isotropic systems or when used with computational fluid dynamics (CFD) codes. However, numerical difficulties can arise for cases where there is a large variation of moments or where two abscissas have similar values. Previous study has demonstrated that introducing an appropriate adjustable factor to the QMOM, the numerical difficulty can be alleviated in some cases with an additional benefit of improving numerical accuracy or significantly reducing computational time. However, no reliable method is available to determine the optimal adjustable factor that allows the highest possible accuracy to be obtained while maintaining computational efficiency. In this work, an adjustable factor is introduced to the DQMOM and a novel procedure is proposed that enables the optimal adjustable factor to be found for a given problem. A number of test cases including pure aggregation, pure breakage, pure growth, aggregation and breakage, aggregation and growth have been carried out. Our results show that the proposed method is capable of either improving numerical accuracy or reducing the computational time for a variety of problems. The novelty of this method is that the optimal adjustable factor is determined based on the actual particle size distribution at a given time, thereby reducing error accumulation. It also allows other factor‐searching procedures to be incorporated in a straightforward manner without influencing the adaptive DQMOM (ADQMOM)itself. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Simultaneous design, scheduling, and optimal control of a methyl‐methacrylate continuous polymerization reactor
Authors: Terrazas‐Moreno Sebastian , Flores‐Tlacuahuac Antonio , Grossmann Ignacio E. 
Published: September 2008

AbstractThis work presents a mixed‐integer dynamic optimization (MIDO) formulation for the simultaneous process design, cyclic scheduling, and optimal control of a methyl methacrylate (MMA) continuous stirred‐tank reactor (CSTR). This article makes two specific contributions. The first consists of incorporating process dynamics into grade transitions to determine changeover times and profiles, as opposed to using fixed changeover times as in previous works dealing with design, scheduling, and dynamic optimization. A second contribution is that the steady states that describe each polymer grade are left as functions of decision variables, which has not been done in the integration of design, scheduling, and dynamic optimization. Also, this work incorporates uncertainty in product demands. The corresponding mathematical formulation includes the differential equations that describe the dynamic behavior of the system, resulting in a MIDO problem. The differential equations were discretized using the simultaneous approach, based on ortogonal collocation on finite elements, rendering a mixed integer non‐linear programming (MINLP) problem, where a profit function is to be maximized. The objective function includes product sales, some capital and operational costs, inventory costs, and transition costs. The optimal solution to this problem involves design decisions: flow rates, feeding temperatures and concentrations, equipment sizing, variables values at steady state; scheduling decisions: grade productions sequence, cycle duration, production quantities, inventory levels; and optimal control results: transition profiles, durations, and transition costs. The problem was formulated and solved in two ways: as a deterministic model and as a two‐stage stochastic programming problem with hourly product demands as uncertain parameters described by discrete distributions. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Genome‐wide association study of response to methylphenidate in 187 children with attention‐deficit/hyperactivity disorder
Authors: Mick Eric , Neale Benjamin , Middleton Frank A. , McGough James J. , Faraone Stephen V. 
Published: September 2008

AbstractWe conducted a genome‐wide association study of symptom response in an open‐label study of a methylphenidate transdermal system (MTS). All DNA extraction and genotyping was conducted at SUNY Upstate Medical University using the Affymetrix Genome‐Wide Human SNP Array 6.0. All quality control and association analyses were conducted using the software package PLINK. After data cleaning and quality control, there were 187 subjects (72% (N = 135) male) with mean age 9.2 ± 2.0 years and 319,722 SNPs available for analysis. The most statistically significant association (rs9627183 and rs11134178; P = 3 × 10−6) fell short of the threshold for a genome‐wide significant association. The most intriguing association among suggestive findings (rs3792452; P = 2.6 × 10−5) was with the metabotropic glutamate receptor 7 gene (GRM7) as it is expressed in brain structures also previously associated with ADHD. Among the 102 available SNPs covering previously studied candidate genes, two SNPs within the norepinephrine transporter gene (NET, SLC6A2) were significant at P ≤ 1 × 10−2. These results should be considered preliminary until replicated in larger adequately powered, controlled samples but do suggest that noradrenergic and possibly glutaminergic genes may be involved with response to methylphenidate. © 2008 Wiley‐Liss, Inc.
Genome‐wide association scan of quantitative traits for attention deficit hyperactivity disorder identifies novel associations and confirms candidate gene associations
Authors: Lasky‐Su Jessica , Neale Benjamin M. , Franke Barbara , Anney Richard J.L. , Zhou Kaixin , Maller Julian B. , Vasquez Alejandro Arias , Chen Wai , Asherson Philip , Buitelaar Jan , Banaschewski Tobias , Ebstein Richard , Gill Michael , Miranda Ana , Mulas Fernando , Oades Robert D. , Roeyers Herbert , Rothenberger Aribert , Sergeant Joseph , Sonuga‐Barke Edmund , Steinhausen Hans Christoph , Taylor Eric , Daly Mark , Laird Nan , Lange Christoph , Faraone Stephen V. 
Published: September 2008

AbstractAttention deficit hyperactivity disorder (ADHD) is a complex condition with environmental and genetic etiologies. Up to this point, research has identified genetic associations with candidate genes from known biological pathways. In order to identify novel ADHD susceptibility genes, 600,000 SNPs were genotyped in 958 ADHD proband‐parent trios. After applying data cleaning procedures we examined 429,981 autosomal SNPs in 909 family trios. We generated six quantitative phenotypes from 18 ADHD symptoms to be used in genome‐wide association analyses. With the PBAT screening algorithm, we identified 2 SNPs, rs6565113 and rs552655 that met the criteria for significance within a specified phenotype. These SNPs are located in intronic regions of genes CDH13 and GFOD1, respectively. CDH13 has been implicated previously in substance use disorders. We also evaluated the association of SNPs from a list of 37 ADHD candidate genes that was specified a priori. These findings, along with association P‐values with a magnitude less than 10−5, are discussed in this manuscript. Seventeen of these candidate genes had association P‐values lower then 0.01: SLC6A1, SLC9A9, HES1, ADRB2, HTR1E, DDC, ADRA1A, DBH, DRD2, BDNF, TPH2, HTR2A, SLC6A2, PER1, CHRNA4, SNAP25, and COMT. Among the candidate genes, SLC9A9 had the strongest overall associations with 58 association test P‐values lower than 0.01 and multiple association P‐values at a magnitude of 10−5 in this gene. In sum, these findings identify novel genetic associations at viable ADHD candidate genes and provide confirmatory evidence for associations at previous candidate genes. Replication of these results is necessary in order to confirm the proposed genetic variants for ADHD. © 2008 Wiley‐Liss, Inc.
SNPs in dopamine D2 receptor gene (DRD2) and norepinephrine transporter gene (NET) are associated with continuous performance task (CPT) phenotypes in ADHD children and their families
Authors: Kollins S.H. , Anastopoulos A.D. , Lachiewicz A.M. , FitzGerald D. , Morrissey‐Kane E. , Garrett M.E. , Keatts S.L. , Ashley‐Koch A.E. 
Published: September 2008

AbstractHaplotype‐tagging SNP analyses were conducted to identify molecular genetic substrates of quantitative phenotypes derived from performance on a Continuous Performance Task (CPT). Three hundred sixty‐four individuals were sampled from 152 families ascertained on the basis of at least one child having ADHD. Probands, their affected and unaffected siblings, and parents were administered a CPT. Four different components of performance were analyzed and tested for association with SNPs from 10 candidate genes involved in monoaminergic function. After correcting for multiple comparisons and controlling for multiple individuals from the same family, significant associations were identified between commission errors and SNPs in the DRD2 gene (rs2075654, rs1079596), and between reaction time variability and a SNP in the NET gene (rs3785155). These findings suggest that commission errors and reaction time variability are excellent candidates as ADHD endophenotypes based on previously published criteria. Results also shed light on the molecular genetic basis of specific processes that may underlie the disorder. © 2008 Wiley‐Liss, Inc.
Chemical modification of polypropylene fibers grafted vinyl imidazole/acrylonitrile copolymer prepared by gamma radiation and its possible use for the removal of some heavy metal ions
Authors: Mostafa Tahia B. 
Published: September 2008

AbstractThe chemical modification of polypropylene (PP) fibers by graft copolymerization with vinylimidazole (VIm) and acrylonitrile (AN) was carried out using γ‐radiation. Preparation conditions, such as irradiation dose, comonomer concentration and composition and type of solvent, affecting the degree of grafting were investigated. The suitable diluent for obtaining reasonable graft VIm/AN copolymer yield was acetone. The higher grafted yield was achieved by increasing the amount of vinylimidazole in comonomer feed solution as well as irradiation dose. The derivatives of PP‐g‐P(VIm/AN) grafted fibers of different functional groups were obtained by treating the grafted fibers with various organic reagents containing reactive amino groups, such as sulpha‐drug compounds, aliphatic‐ and aromatic amines. Characterization of the obtained graft copolymers and their chemical treatments with different amines was also investigated. It was observed that the nitrile group in PP‐g‐P(VIm/AN) polymer undergoes simple addition reaction via nucleophilic interaction mechanism to produce the corresponding PP‐graft‐P(vinylimidazole/acrylomidine) derivatives. The ability of the grafted fibers and their treated forms to absorb some metal ions as Cd, Hg, and Pb from their individual and mixture solutions was evaluated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009.
Synthesis and thermal studies of block copolymers from NR and MDI‐based polyurethanes
Authors: Sukumar Prema , Jayashree V. , Gopinathan Nair M. R. , Radhakrishnan Nair M. N. 
Published: September 2008

AbstractFive series of block copolymers based on natural rubber and polyurethane were prepared from hydroxyl terminated liquid natural rubber (HTNR) and polyurethane (PU) formed by the reaction of diphenyl methane—4,4′—diisocyanate (MDI) with a chain extender diol, viz., ethylene glycol (EG)/propylene glycol (PG)/1,4‐butane diol (1,4‐BDO)/1,3‐butane diol (1,3‐BDO)/bisphenol A (BPA), by solution polymerization. Structural characterization of the block copolymers was done by infrared (IR) analysis. Thermal studies and kinetic analysis on thermal degradation of the block copolymers were undertaken with the view of characterizing them. Energy of activation and entropy change for the degradation were determined and a probable mechanism for the solid state degradation was suggested which corresponds to a three dimensional diffusion mechanism. DSC analysis has been used for the study of microphase separation in the block copolymers. Thermal transition of the hard segment significantly varies with the extender diol which highlights the effect of extender diol structure on the chain stiffening mechanism. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Blends of PVC and epoxidized liquid natural rubber: Studies on impact modification
Authors: Radhakrishnan Nair M. N. , Biju P. K. , Thomas George V. , Gopinathan Nair M. R. 
Published: September 2008

AbstractLiquid natural rubber of different molecular masses L‐LNR, and H‐LNR were subjected to varying degree of epoxidation (L‐ELNR‐10, L‐ELNR‐20, L‐ELNR‐30, L‐ELNR‐40, L‐ELNR‐50, H‐LNR‐20, and H‐LNR‐50) and the products were incorporated into PVC at various compositions by the solution blending method. These blend systems were subjected to tensile testing, tensile impact measurements, and SEM studies. It was observed that blends with L‐ELNR‐20 showed highest impact strength modification, followed by L‐ELNR‐10 and L‐ELNR‐30. High impact properties showed by these blends are attributed to the optimum level of compatibility existing between the blend components. Tensile impact fracture studies revealed that the failure pattern for this blend system is intermediate between the brittle fracture of rigid PVC and ductile fracture of PVC/L‐ELNR‐50 samples. Blends up to 30 mol % of epoxidation showed partially compatible heterogeneous nature exhibiting domain morphology. Blends of liquid rubber with higher degree of epoxidation showed deterioration in tensile strength, modulus, yield strength, and tensile impact strength due to plasticization of PVC caused by the higher polar interaction between PVC chains and the oxirane rings. Effect of ELNR molecular weight was studied and it is found that the impact modification is higher for the L‐ELNR blends compared to the H‐ELNR blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Transport abilities of new synthesised membrane materials incorporating tetrapyrazolic tripods
Authors: Malek Fouad , Radi Smaail 
Published: September 2008

AbstractThe synthesis of new membrane materials was carried out by photopolymerisation of formulation that contain the active tetrapyrazolic tripods monomers spread on a polyacrylonitrile support. The obtained membrane films were applied for their facilitated transport and extraction power towards Cd(II), Pb(II), and Hg(II). We have determined both the diffusion flux F of different cations and the selectivity S of the prepared membranes towards each cations. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Polymer model of cancer cell adhesion to glycosaminoglycan substrates using the radius of gyration
Authors: Peramo Antonio , Meads Mark B. , Dalton William S. , Matthews W. Garrett 
Published: September 2008

AbstractThe hypothesis that the adhesion of whole cancer cells to glycosaminoglycan (GAG) substrates is a function of polysaccharide radius of gyration is presented. We use a worm‐like chain (WLC) polymer model describing the global structure of the GAGs that will take into account the charge distribution and contour length of the polysaccharide implicitly in its radius of gyration to relate these parameters to cell adhesion. Specifically, we present measurements of the in vitro adhesion of cancer cells to isolated and individualized GAG substrates. We find that adhesion of the cells has a linear response with the radius of gyration and is essentially controlled by the charge per dimer. This dominating mechanism is not eliminated when the cells are subjected to resuspension in media with heparin. We then propose how these physical properties could be used to predict the preferred molecular structures of compounds for use as antimetastatic or antiinflammatory agents by comparing our results with known effective molecules. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Confocal microscopy study of polymer microcapsules for enzyme immobilisation in paper substrates
Authors: Kouisni L. , Rochefort D. 
Published: September 2008

AbstractThe goal of this research is to develop the technology platform required for the production of bioactive paper based on enzymes as bioactive agents. The immobilization platform described here is based on microencapsulation, which consists in the entrapment of biomolecules in the core of hollow spheres made by a semipermeable membrane. The capsules containing the enzymes can be either deposited on paper or mixed with paper pulp to prepare a bioactive paper. The activity of encapsulated laccase was compared with that of free enzyme using its reaction with the o‐phenylenediamine (OPD) substrate. Confocal Laser Scanning Microscopy (CLSM) is used to study the location of protein in microcapsules and provides explanations for differences in activity of encapsulated laccase. The location of protein in microcapsules was determined using BSA modified with the fluorescent tag sulforhodamine. Polyethyleneimine microcapsules were modified with fluorescein isothiocyanate allowing the simultaneous identification of capsule walls and of encapsulated proteins. From CLSM analysis, proteins were found to favor the wall of the capsules because of strong ionic attraction with the charged polymer. BSA was found to some extent in the core of the capsules and encapsulation of higher loadings increased the proportion of core proteins. We will also present our results on the incorporation of microcapsules in a paper substrate. CLSM was used in this section to determine the distribution and density of tagged microcapsules in the paper substrate. The response of immobilized laccase to a common substrate will also be described. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009