bluuebunny/crossref_metadata_2025_split huggingface dataset:
A CFD‐PBM‐PMLM integrated model for the gas–solid flow fields in fluidized bed polymerization reactors
Authors: Yan Wei‐Cheng , Luo Zheng‐Hong , Lu Ying‐Hua , Chen Xiao‐Dong 
Published: June 2011

AbstractAlthough the use of computational fluid dynamics (CFD) model coupled with population balance (CFD‐PBM) is becoming a common approach for simulating gas–solid flows in polydisperse fluidized bed polymerization reactors, a number of issues still remain. One major issue is the absence of modeling the growth of a single polymeric particle. In this work a polymeric multilayer model (PMLM) was applied to describe the growth of a single particle under the intraparticle transfer limitations. The PMLM was solved together with a PBM (i.e. PBM‐PMLM) to predict the dynamic evolution of particle size distribution (PSD). In addition, a CFD model based on the Eulerian‐Eulerian two‐fluid model, coupled with PBM‐PMLM (CFD‐PBM‐PMLM), has been implemented to describe the gas–solid flow field in fluidized bed polymerization reactors. The CFD‐PBM‐PMLM model has been validated by comparing simulation results with some classical experimental data. Five cases including fluid dynamics coupled purely continuous PSD, pure particle growth, pure particle aggregation, pure particle breakage, and flow dynamics coupled with all the above factors were carried out to examine the model. The results showed that the CFD‐PBM‐PMLM model describes well the behavior of the gas–solid flow fields in polydisperse fluidized bed polymerization reactors. The results also showed that the intraparticle mass transfer limitation is an important factor in affecting the reactor flow fields. © 2011 American Institute of Chemical Engineers AIChE J, 58: 1717–1732, 2012
New antimicrobial agents: The synthesis of Schiff base polymers containing transition metals and their characterization and applications
Authors: Nishat Nahid , Rasool Raza , Parveen Shadma , Khan Shamim Ahmad 
Published: June 2011

AbstractA new polymeric Schiff base containing formaldehyde and 2‐thiobarbituric acid moieties was synthesized by the condensation of a monomeric Schiff base derived from 2‐hydroxyacetophenone and hydrazine. Polymer–metal complexes were also synthesized by the reaction of the polymeric Schiff base with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) acetate. The polymeric Schiff base and its polymer–metal complexes were characterized with magnetic moment measurements, elemental analyses, and spectral techniques (infrared, 1H‐NMR, and ultraviolet–visible). The thermal behaviors of these coordination polymers were studied by thermogravimetric analysis in a nitrogen atmosphere up to 800°C. The thermal data revealed that all of the polymer–metal complexes showed higher thermal stabilities than the polymeric Schiff base and also ascribed that the Cu(II) polymer–metal complex showed better heat resistant properties than the other polymer–metal complexes. The antimicrobial activity was screened with the agar well diffusion method against various selected microorganisms, and all of the polymer–metal complexes showed good antimicrobial activity. Among all of the complexes, the antimicrobial activity of the Cu(II) polymer–metal complex showed the highest zone of inhibition because of its higher stability constant and may be used in biomedical applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Correlation of Arrhenius parameters for UHMWPE synthesis with ethylene solubility characteristics in different polymerization media
Authors: Kishor Rupak , Padmanabhan Sudhakar , R Sarma Krishna , Patel Viral , Sharma Shashikant , Parikh Parimal A. 
Published: June 2011

AbstractThe effect of different polymerization media like n‐hexane, cyclohexane, isooctane, n‐decane, toluene, varsol, and light normal paraffin (LNP) on the kinetics of the slurry polymerization of ethylene using a highly active Ziegler Natta (ZN) catalyst for synthesizing UHMWPE was studied. Attempts have been made to determine the solubility of ethylene in the above polymerization media in a very basic manner and to correlate same with the process activation energy based on the Arrhenius plots. The ethylene solubility seemed to depend on the number of carbon atoms in the media, besides other parameters like geometry, dipole moment, etc. It is obvious and well understood that the monomer (ethylene) concentration has a direct bearing on the polymerization kinetics, which influenced the activation energy (Ea) besides other parameters like catalyst/cocatalyst concentration, temperature, etc which were kept constant during the study. The role of the catalyst system in controlling the activation energy was also further exemplified by employing a different ZN catalyst system wherein higher activation energy was observed. This was ascribed to restricted activation pathways for the catalyst under the comparable experimental conditions employed. As soon as better activation pathways for the catalyst were enabled the activation energy dropped down remarkably. The Ea for the synthesis of ultra‐high molecular weight polyethylene (UHMWPE) using traditional MgCl2 supported Ti catalyst was found to be 5–12 kcal/mol which compared well with the values obtained by other researchers using other similar catalyst systems for different ethylene polymerization processes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Metformin Induces G1 Cell Cycle Arrest and Inhibits Cell Proliferation in Nasopharyngeal Carcinoma Cells
Authors: Zhao Li , Wen Zhi‐Hua , Jia Chun‐Hong , Li Ming , Luo Shen‐Qiu , Bai Xiao‐Chun 
Published: June 2011

AbstractIt has been reported that metformin, a biguanide derivative widely used in type II diabetic patients, has antitumor activities in some cancers by activation of AMP‐activated protein kinase (AMPK). But its role in nasopharyngeal carcinoma (NPC) is not known. Here, we reported for the first time that 1–50 mM of metformin in a dose‐ and time‐dependent manner suppressed cell proliferation and colony formation in NPC cell line, C666‐1. Further studies revealed that the protein level of cyclin D1 decreased and the percentage of the cells in G0/G1 phase increased by 5 mM metformin treatment. Metformin also induced the phosphorylation of AMPK (T172) in a time‐dependent manner. Mammalian target of rapamycin complex 1 (mTORC1), which is negatively regulated by AMPK and plays a central role in cell growth and proliferation, was inhibited by metformin, as manifested by dephosphorylation of its downstream targets 40S ribosomal S6 kinase 1 (S6K1) (T389), the eukaryotic translation initiation factor 4E (eIF4E)‐binding protein 1 (4E‐BP1) (T37/46) and S6 (S235/236) in C666‐1 cells. In a summary, metformin prevents proliferation of C666‐1 cells by down‐regulating cyclin D1 level and inducing G1 cell cycle arrest. AMPK‐mediated inhibition of mTORC1 signaling may be involved in this process. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.
Normal Location Of Thumb/Big Toe may be Related to Programmed Cell Death in the Preaxial Area of Embryonic Limb
Authors: Kimura Sumiko , Yamada Shigehito , Naruse Ichiro 
Published: June 2011

AbstractThe forelimbs and hindlimbs of newborn Polydactyly Nagoya (Pdn) mice were examined to analyze the roles of programmed cell death (PCD) in the preaxial region of the limb. Special attention was paid to the relationship between the PCD in the preaxial area and the location and shape of the first digit (thumb/big toe). Although a large, bifurcated or duplicated thumb/big toe appeared in Pdn/+ mice, digit I (thumb/big toe) in Pdn/+ mice, as in +/+ ones, was located more ventro‐proximally than the other four digits. On the other hand, abnormal preaxial digits of the fore/hindlimb in Pdn/Pdn mice lay distally and were aligned at the radial/tibial end of a serial curved plane formed by digits II–V; that is, a thumb and big toe of normal shape and location were not detectable in any preaxial digits of Pdn/Pdn mice. In the limb development of Pdn mouse embryos on Day 11‐12, PCD did not occur in the preaxial mesoderm of fore/hindlimb only in one‐fourths of all embryos obtained by Pdn/+ x Pdn/+ mating. In addition to digital rays II‐V, extra preaxial digital rays appeared in the prominent preaxial expansion of fore/hindlimbs in these embryos on early Day 12. These abnormal limb configurations in embryos were closely similar to those in Pdn/Pdn newborn mice. The present findings suggest that PCD in the preaxial region not only prevents the formation of extra digits but also determines the location of the thumb/big toe for the normal limb morphogenesis. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.
The development of perceptual expertise for faces and objects in autism spectrum conditions
Authors: Damiano Cara , Churches Owen , Ring Howard , Baron‐Cohen Simon 
Published: June 2011

AbstractPrevious research indicates that individuals with autism spectrum conditions (ASC) do not develop face expertise to the same extent as typical individuals. Yet it remains unclear whether this atypicality is specific to faces or related to more pervasive perceptual or cognitive deficits involved in the actual process of gaining expertise. To address this question, we examined the extent to which adults with ASC were capable of developing expertise with non‐face objects. To become experts, all participants completed a 2‐week training program with novel objects, known as Greebles. Level of expertise was assessed throughout training by measuring the ability to identify Greebles on an individual level. The perceptual strategies acquired as a result of expertise were measured through an inversion effect task completed before and after training, in which performance with upright Greebles and faces was compared to performance with inverted Greebles and faces. After expertise training, it was found that individuals in both the ASC and the typical group successfully achieved expertise and showed an enhanced Greeble inversion effect as a result of training. The development of an inversion effect with Greebles suggests that individuals with ASC may employ the same processing strategies as the typical group. Although exploratory, these findings have implications for understanding the nature of the face processing deficit in ASC as well as offering potential insights into face processing interventions for individuals with ASC. Autism Res 2011, 4:297–301. © 2011 International Society for Autism Research, Wiley Periodicals, Inc.
Überarbeitung der DAfStb‐Richtlinie Instandsetzung – Statusbericht
Authors: Bastert Heinrich , Dickhaut Heinz Dieter , Eßer Angelika , Hintzen Wilhelm , Hohberg Inga , Kühne Hans‐Carsten , Kühner Stefan , Meyer Lars , Raupach Michael , Westendarp Andreas , Wiens Udo 
Published: July 2011

AbstractDerzeit erfolgt in mehreren Arbeitsgruppen unter Einbindung interessierter Kreise die Überarbeitung der 2001 erschienenen Richtlinie “Schutz und Instandsetzung von Betonbauteilen” (Instandsetzungsrichtlinie) des Deutschen Ausschusses für Stahlbeton e.V. (DAfStb). Hierüber wird in dem nachfolgenden Beitrag berichtet, um der Fachwelt frühzeitig darzustellen, in welche Richtung die Fortschreibung des Regelwerkes geplant ist.Die geplante neue Richtlinie wird nach derzeitigem Beratungsstand eine deutliche inhaltliche Erweiterung erfahren. Daher wird sie in “Richtlinie für die Instandhaltung von Betonbauteilen” (Instandhaltungsrichtlinie) umbenannt und wird Festlegungen zu der grundsätzlichen Vorgehensweise bei der Instandhaltung unter Berücksichtigung der Komponenten Wartung, Inspektion, Instandsetzung und Verbesserung in Anlehnung an DIN 31051 enthalten. Da diese umfassenderen Aufgaben deutlich präziser beschrieben werden, konkretisieren sich auch die Anforderungen an die erforderliche Qualifikation des sachkundigen Planers, der zukünftig verstärkt die “Restnutzungsdauer” bei seiner Planung beachten und in entsprechende Maßnahmen umsetzen muss.Mit den Ergänzungen und Änderungen wird die Richtlinie an die aktuellen Entwicklungen und Regelungen im Betonbau angepasst. Gleichzeitig gewinnt die Planungsleistung erheblich an Bedeutung. Für Instandsetzungsprodukte gemäß DIN EN 1504 werden, die Beseitigung derzeit noch enthaltener Unklarheiten und technischer Defizite auf europäischer Ebene vorausgesetzt, Verwendbarkeitsmöglichkeiten aufgezeigt. Die Ausführung von Instandhaltungsmaßnahmen wird durch die Einführung von Überwachungsklassen mit zugehörigen Anforderungen an die durchzuführenden Prüfungen spezifiziert und damit konkretisiert.
Routine colonoscopy following acute uncomplicated diverticulitis
Authors: Westwood D A , Eglinton T W , Frizelle F A 
Published: June 2011

AbstractBackgroundThe evidence supporting current recommendations that the colon should be evaluated following an initial episode of acute diverticulitis is poor. The aim of this study was to clarify whether acute uncomplicated diverticulitis is a valid indication for subsequent colonoscopy/computed tomography (CT) colonography.MethodsThis was a retrospective longitudinal study of patients with an initial presentation of acute uncomplicated diverticulitis on the basis of CT criteria, at a single institution between January 2004 and December 2008.ResultsA radiological diagnosis of acute uncomplicated diverticulitis was made in 292 patients. Some 205 patients underwent subsequent colonic evaluation or had undergone colonoscopy/CT colonography within the preceding 2 years. Colorectal polyps were present in 50 patients (24·4 per cent). Twenty patients (9·8 per cent) had hyperplastic polyps and 19 (9·3 per cent) had adenomas. Eleven patients (5·4 per cent) had advanced colonic neoplasia, including one (0·5 per cent) with a colorectal cancer. One patient had inflammatory bowel disease (IBD). The patients with colorectal cancer and IBD had clinical indicators that independently warranted colonoscopy. None of the 87 patients who did not undergo colonic evaluation had a diagnosis of colorectal cancer registered with the New Zealand Cancer Registry.ConclusionThe yield of advanced colonic neoplasia in this cohort was equivalent to, or less than that detected on screening asymptomatic average-risk individuals. In the absence of other indications, subsequent evaluation of the colon may not be required to confirm the diagnosis of diverticulitis.
Stakeholders' Engagement in Promoting Sustainable Development: Businesses and Urban Forest Carbon
Authors: Poudyal Neelam C. , Siry Jacek P. , Bowker J. M. 
Published: June 2011

ABSTRACTTo better understand how businesses' motivation and support for green projects varies by their organizational objectives and characteristics, this study investigates a case of urban forestry carbon credits in a broader context of climate change mitigation efforts. Companies and organizations currently participating in the Chicago Climate Exchange (CCX) were surveyed regarding their perception of consumers' concerns with climate change, attitudes toward government regulations, factors important to their emission management decisions, and their interest in buying and paying premiums for carbon credits sourced from urban forestry. Statistical analysis of the responses reveals noticeable differences among various types of business organizations. The findings are useful for understanding how businesses respond to different kinds of green products and will help in the development of green product markets. Finally, the results will help in developing effective environmental policies that respond well to businesses' objectives and preferences. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.
On the Nature of Actinide– and Lanthanide–Metal Bonds in Heterobimetallic Compounds
Authors: Vlaisavljevich Bess , Miró Pere , Cramer Christopher J. , Gagliardi Laura , Infante Ivan , Liddle Stephen T. 
Published: June 2011

AbstractEleven experimentally characterized complexes containing heterobimetallic bonds between elements of the f‐block and other elements were examined by quantum chemical methods: [(η5‐C5H5)2(THF)LuRu(η5‐C5H5) (CO)2], [(η5‐C5Me5)2(I)ThRu(η5‐C5H5) (CO)2], [(η5‐C5H5)2YRe(η5‐C5H5)2], [{N(CH2CH2NSiMe3)3}URe(η5‐C5H5)2], [Y{Ga(NArCh)2}{C(PPh2NSiH3)2}(CH3OCH3)2], [{N(CH2CH2NSiMe3)3}U{Ga(NArCH)2}(THF)], [(η5‐C5H5)3UGa(η5‐C5Me5)], [Yb(η5‐C5H5){Si(SiMe3)3(THF)2}], [(η5‐C5H5)3U(SnPh3)], [(η5‐C5H5)3U(SiPh3)], and (Ph[Me]N)3USi(SiMe3)3. Geometries in good agreement with experiment were obtained at the density functional level of theory. The multiconfigurational complete active space self‐consistent field method (CASSCF) and subsequent corrections with second order perturbation theory (CASPT2) were applied to further understand the electronic structure of the lanthanide/actinide–metal (or metal–metalloid) bonds. Fragment calculations and energy‐decomposition analyses were also performed and indicate that charge transfer occurs from one supported metal fragment to the other, while the bonding itself is always dominated by ionic character.
Free‐surface turbulent flow induced by a Rushton turbine in an unbaffled dish‐bottom stirred tank reactor: LDV measurements and CFD simulations
Authors: Haque J. N. , Mahmud T. , Roberts K. J. , Liang J. K. , White G. , Wilkinson D. , Rhodes D. 
Published: June 2011

AbstractLaser Doppler velocimetry measurements and computational fluid dynamic (CFD) simulations of turbulent flows with free‐surface vortex in an unbaffled dish‐bottom stirred tank reactor agitated by a Rushton turbine are presented. Measurements of the three mean and fluctuating components of the velocity vector are made in order to characterise the flow field and to provide data for CFD model validation. An Eulerian–Eulerian multiphase flow model coupled with a volume‐of‐fluid method for capturing the gas–liquid interface is applied to determine the vortex shape and to compute the flow field. Turbulence is modelled using the standard k−ε, shear‐stress transport and the differential Reynolds‐stress model with two variants of the pressure‐strain correlation. The predicted mean flow field obtained using all four turbulence models are on the whole similar and generally in good agreement with measurements. However, the Reynolds‐stress models provide somewhat better predictions of the mean axial velocity. The turbulent kinetic energy is well predicted in the flow below the impeller, near the bottom of the tank; whereas it is underpredicted in the region close to the impeller and near the wall by all turbulence models.
Synthesis, Crystal Structure and Thermal Behavior of GZTO·H2O
Authors: Zhong Yitang , Huang Jie , Song Jirong , Xu Kang , Zhao Dan , Wang Liqin , Zhang Xinyu 
Published: July 2011

AbstractGuanidimium‐4,4‐azo‐1‐hydro‐1,2,4‐triazol‐5‐one (GZTO·H2O) was synthesized from 4‐amino‐1,2,4‐triazol‐5‐one as a starting material by two‐step including oxidation coupling using acid KMnO4 and reaction with (NH2)2CNH·HNO3 (GN) in KOH solution. The single crystal of the title compound was obtained by slow evaporation method at room temperature, and its structure was firstly determined with X‐ray single‐crystal diffractometer. It is a orthorhombic crystal, space group Pbca with cell dimensions of a=1.0459(2) nm, b=1.3584(3) nm, c=1.6103(3) nm, α=90.00(10)°, β=90.00(11)°, γ=90.00(11)°, V=2.2878(8) nm3, Z=8, Dc=1.587 g·cm−3, F(000)=1136, µ=0.132 mm−1, R1=0.0455, wR2=0.1397. The thermal behavior of GZTO·H2O was studied under a non‐isothermal condition by DSC‐TGA method, and its thermal decomposition process can be divided into three stages, and the first stage is an intense exothermic decomposition process. The second stage and the third stage are slow exothermic decomposition processes. The critical temperature of thermal explosion is 237.74°C.
Cr(VI) Immobilization Process in a Cr‐Spiked Soil by Zerovalent Iron Nanoparticles: Optimization Using Response Surface Methodology
Authors: Alidokht Leila , Khataee Ali Reza , Reyhanitabar Adel , Oustan Shahin 
Published: June 2011

AbstractThe response surface methodology involving the five‐level central composite design (CCD) was employed to model and optimize the Cr(VI) immobilization process in a Cr‐spiked soil using starch‐stabilized zerovalent iron nanoparticles (ZVIn). ZVIn were synthesized via a borohydride reduction method and characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). All Cr(VI) immobilization experiments were conducted in a batch system. The variables for the CCD optimization were the ZVIn dosage (% w/w), reaction time (min), and initial Cr(VI) concentration in soil (mg/kg). The predicted response values by the second‐order polynomial model were found to be in good agreement with experimental values (R2 = 0.968 and adj‐R2 = 0.940). The optimization result showed that the Cr(VI) immobilization efficiency presented the maximal result (90.63%) at the following optimal conditions: ZVIn dosage of 1.5% w/w, reaction time of 60 min, and an initial Cr(VI) concentration of 400 mg/kg.
A role for katanin in plant cell division: Microtubule organization in dividing root cells of fra2 and lue1Arabidopsis thaliana mutants
Authors: Panteris Emmanuel , Adamakis Ioannis‐Dimosthenis S. , Voulgari Georgia , Papadopoulou Galini 
Published: June 2011

AbstractSevering of microtubules by katanin has proven to be crucial for cortical microtubule organization in elongating and differentiating plant cells. On the contrary, katanin is currently not considered essential during cell division in plants as it is in animals. However, defects in cell patterning have been observed in katanin mutants, implying a role for it in dividing plant cells. Therefore, microtubule organization was studied in detail by immunofluorescence in dividing root cells of fra2 and lue1 katanin mutants of Arabidopsis thaliana. In both, early preprophase bands consisted of poorly aligned microtubules, prophase spindles were multipolar, and the microtubules of expanding phragmoplasts were elongated, bended toward and connected to the surface of daughter nuclei. Accordingly, severing by katanin seems to be necessary for the proper organization of these microtubule arrays. In both fra2 and lue1, metaphase/anaphase spindles and initiating phragmoplasts exhibited typical organization. However, they were obliquely oriented more frequently than in the wild type. It is proposed that this oblique orientation may be due to prophase spindle multipolarity and results in a failure of the cell plate to follow the predetermined division plane, during cytokinesis, producing oblique cell walls in the roots of both mutants. It is therefore concluded that, like in animal cells, katanin is important for plant cell division, influencing the organization of several microtubule arrays. Moreover, failure in microtubule severing indirectly affects the orientation of the division plane. © 2011 Wiley‐Liss, Inc.
The Inverse Type II β‐Turn on D‐Trp‐Phe, a Pharmacophoric Motif for MOR Agonists
Authors: Gentilucci Luca , Tolomelli Alessandra , De Marco Rossella , Spampinato Santi , Bedini Andrea , Artali Roberto 
Published: June 2011

AbstractHerein we propose the D‐Trp‐Phe sequence within an inverse type II β‐turn as a new kind of pharmacophoric motif for μ‐opioid receptor (MOR) cyclopeptide agonists. Initially, we observed that c[Tyr‐D‐Pro‐D‐Trp‐Phe‐Gly] (4), an analogue of endomorphin‐1 (H‐Tyr‐Pro‐Trp‐Phe‐NH2) lacking the crucial protonatable amino group of Tyr 1, is a MOR agonist with 10−8 M affinity. Molecular docking analysis suggested that the relevant interactions with the receptor involve D‐Trp‐Phe. The bioactive conformation of this region was investigated by selected derivatives of 4 designed to adopt an inverse type II β‐turn. These efforts led to c[Tyr‐Gly‐D‐Trp‐Phe‐Gly] (14) and to the cyclotetrapeptide c[D‐Asp‐1‐amide‐β‐Ala‐D‐Trp‐Phe] (15), showing improved nanomolar affinity. Both 14 and 15 selectively bind MOR, as they have negligible affinity for the κ‐ and δ‐opioid receptors. Both 14 and 15 behave as partial MOR agonists in functional assays. Conformational and docking analyses confirm the role of the inverse β‐turn in binding. These results indicate that the D‐Trp‐Phe inverse β‐turn structure can be used for designing non‐endomorphin‐like peptidomimetic opioid agonists in general, characterized by an atypical mechanism of interaction between ligand and receptor.