bluuebunny/crossref_metadata_2025 huggingface dataset:
Periodic section modeling of convective continuous powder mixing processes
Authors: Gao Yijie , Ierapetritou Marianthi , Muzzio Fernando
Published: January 2011

This study aims to develop a general model of the convective continuous mixing process. The main idea is that continuous mixing can be considered as a combination of powder flow and mixing processes. Although powder flow is characterized by the residence time distribution (RTD), powder mixing can be described by a batch mixing process simulated in one periodic section of the continuous mixer. By characterizing the two processes separately, we can calculate the number of sections required to achieve certain homogeneity. In this study, continuous mixing is simulated using the discrete element method, and segregating and non‐segregating mixing cases are tested to investigate the applicability of the model. Results show satisfactory predictions by the model, which is able to characterize the continuous mixing performance of both mixing cases. On the basis of this study, we were also able to suggest a novel method in design and control of continuous powder mixing systems. © 2011 American Institute of Chemical Engineers AIChE J , 2012
Modeling multistream heat exchangers with and without phase changes for simultaneous optimization and heat integration
Authors: Kamath Ravindra S. , Biegler Lorenz T. , Grossmann Ignacio E.
Published: January 2011

A new equation‐oriented process model for multistream heat exchangers (MHEX) is presented with a special emphasis on handling phase changes. The model internally uses the pinch concept to ensure the minimum driving force criteria. Streams capable of phase change are split into substreams corresponding to each of the phases. A novel disjunctive representation is proposed that identifies the phases traversed by a stream during heat exchange and assigns appropriate heat loads and temperatures for heat integration. The disjunctive model can be reformulated to avoid Boolean (or integer) variables using inner minimization and complementarity constraints. The model is suitable for optimization studies, particularly when the phases of the streams at the entry and exit of the MHEX are not known a priori. The capability of the model is illustrated using two case studies based on cryogenic applications. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Validation of the similar particle assembly (SPA) model for the fluidization of Geldart's group A and D particles
Authors: Mokhtar M. A. , Kuwagi K. , Takami T. , Hirano H. , Horio M.
Published: January 2011

The similar particle assembly (SPA) model proposed for large‐scale discrete element method simulation was validated. The SPA model describes the scaling law for the motion of particles in an assembly, which is derived from the equation of motion of a particle. In the SPA model, particles with similar physical or chemical properties are represented by a single particle, which is called the representative particle. The local assembly of particles in the original bed is supposed to be maintained in the bed with the representative particles. The SPA model was validated by numerical simulations of a 2D fluidized bed of noncohesive and cohesive particles. Using the SPA model, the flow behavior of the representative particles of a certain magnification can be made similar to that of the original particles with significantly less computational load. A good approximation of bubble size distribution between the SPA bed and the original bed was obtained. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Probability density function simulation of turbulent reactive gas‐solid flow in a FCC riser
Authors: Prasad Vegendla Suryanarayana , Heynderickx Geraldine J. , Marin Guy B.
Published: January 2011

A newly developed hybrid solution algorithm applicable on turbulent multiphase, gas‐solid, reactive flows is presented. A finite volume (FV) and a probability density function (PDF) method are combined. The FV technique is used to solve the total mass and momentum conservation equations together with the k‐ε turbulence equation for the gas phase and the granular temperature equation for the solid phase. The PDF method is applied to solve the species continuity equations and avoids the need to model the chemical source terms in the latter. Stochastic differential equations (SDEs) are introduced as replicas of the transported composition PDF equations. The notional‐particle‐based Monte‐Carlo technique is used to solve the PDF model equations. The hybrid FV/PDF solution algorithm is applied to simulate a fluid catalytic cracking (FCC) riser using a 12‐lump kinetic model. A good agreement between simulated results and available plant data is obtained. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Prediction of turbulent gas‐solid flow in a duct with a 90° bend using an Eulerian‐Lagrangian approach
Authors: Njobuenwu Derrick O. , Fairweather Michael , Yao Jun
Published: January 2011

A dilute, particle‐laden turbulent flow in a square cross‐sectioned duct with a 90° bend is modeled using a three‐dimensional Eulerian‐Lagrangian approach. Predictions are based on a second‐moment turbulence closure, with particles simulated using a Lagrangian particle tracking technique, coupled to a particle‐wall interaction algorithm and a random Fourier series method used to model particle dispersion. The performance of the model is tested for a gas‐solid flow in a horizontal‐to‐vertical duct, with predictions showing good agreement with experimental data. In particular, the consistent use of anisotropic and fully three‐dimensional approaches throughout yields predictions that result in fluctuating particle velocities in acceptable agreement with data. © 2011 American Institute of Chemical Engineers AIChE J, 2012
An experimental study of Mesler entrainment on a surfactant‐covered interface: The effect of drop shape and Weber number
Authors: Mills B. H. , Saylor J. R. , Testik F. Y.
Published: January 2011

Mesler entrainment is the formation of large numbers of small bubbles which occurs when a drop strikes a liquid reservoir at a relatively low velocity. Existing studies of Mesler entrainment have focused almost exclusively on water as the working fluid in a nominally clean state, where even very small levels of contamination can cause significant changes in surface tension that affect the repeatability of the results. Herein water combined with the soluble surfactant Triton X‐100 is used as the working fluid in an attempt to stabilize the state of the water surface. Despite this approach, nominally identical drops did not always result in the same bubble formation event. Accordingly, Mesler entrainment was quantified by its frequency of occurrence for drops having the same nominal diameter and impact velocity. This frequency of occurrence was found to be well correlated to both the Weber number and the shape of the drop on impact. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Drop impact and agglomeration under static powder bed conditions
Authors: Lee Andrew C. S. , Sojka Paul E.
Published: January 2011

The influence of impact conditions (reported in terms of Weber and Reynolds numbers) on nucleus formation was studied for single drops striking a static glass bead bed. Results from high speed images showed that the nucleation rate is not influenced by liquid physical properties (density, surface tension, viscosity) for drops that spread significantly (30 < We < 233). Results also showed that nucleus size is determined by how much liquid penetrates into the bed during drop spreading, so does depend on surface tension and liquid density. A corresponding analytical model, derived from first principles, predicts nucleus size to with 1.5% using only liquid physical and powder bed properties, plus the experimentally measured drop spreading behavior. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Health‐related quality of life in children and adolescents with stroke, self‐reports, and parent/proxies reports: Cross‐sectional investigation
Authors: Neuner Bruno , von Mackensen Sylvia , Krümpel Anne , Manner Daniela , Friefeld Sharon , Nixdorf Sarah , Frühwald Michael , deVeber Gabrielle , Nowak‐Göttl Ulrike
Published: January 2011

Objective:

Limited data are available on health‐related quality of life (HR‐QoL) in pediatric stroke survivors. The aim of the present study was to assess HR‐QoL by self‐assessment and parent/proxy‐assessment in children and adolescents who survived a first stroke episode.

Methods:

We investigated HR‐QoL in pediatric stroke survivors (71 preschool children [G1] and 62 school children/adolescents [G2]) and in 169 healthy controls. HR‐QoL was assessed in patients and parents/proxies with the generic KINDL‐R questionnaire exploring overall well‐being and 6 well‐being subdimensions (physical, psychological, self‐esteem, family‐related, friend‐related, and school‐related). In pediatric stroke survivors the neurological long‐term outcome was measured with the standardized Pediatric Stroke Outcome Measure.

Results:

Of stroke survivors, 65% exhibited at least 1 neurologic disability. Pediatric stroke survivors reported lower overall well‐being compared with healthy controls. In G2 stroke patients, friend‐related well‐being respectively emotional well‐being was significantly reduced compared with healthy controls (73.0 vs 85.0 points; p < 0.001 respectively 80.2 vs 84.5 points; p = 0.049). Parents/proxies of both stroke survivors rated the overall well‐being and all subdimensions (except family‐related and school‐related well‐being in G1 and G2 stroke survivors and physical functioning in G2 stroke survivors) lower compared with parents/proxies of healthy children/adolescents. Overall well‐being was significantly reduced in children with moderate/severe neurological deficits compared with normal/mildly affected patients (75.5 vs 83.3 points, p = 0.01). Neonatal stroke survivors reported a significantly better neurological long‐term outcome compared to childhood stroke survivors (82.0 vs 75.0 points; p = 0.005).

Interpretation:

Pediatric stroke survivors compared with healthy controls are strongly affected regarding their overall well‐being and older children/adolescents regarding their well‐being with peers. Ann Neurol 2011;
Dopaminergic pathway reconstruction by Akt/Rheb‐induced axon regeneration
Authors: Kim Sang Ryong , Chen Xiqun , Oo Tinmarla F. , Kareva Tatyana , Yarygina Olga , Wang Chuansong , During Matthew , Kholodilov Nikolai , Burke Robert E.
Published: January 2011

Objective:

A prevailing concept in neuroscience has been that the adult mammalian central nervous system is incapable of restorative axon regeneration. Recent evidence, however, has suggested that reactivation of intrinsic cellular programs regulated by protein kinase B (Akt)/mammalian target of rapamycin (mTor) signaling may restore this ability.

Methods:

To assess this possibility in the brain, we have examined the ability of adenoassociated virus (AAV)‐mediated transduction of dopaminergic neurons of the substantia nigra (SN) with constitutively active forms of the kinase Akt and the GTPase Ras homolog enriched in brain (Rheb) to induce regrowth of axons after they have been destroyed by neurotoxin lesion.

Results:

Both constitutively active myristoylated Akt and hRheb(S16H) induce regrowth of axons from dopaminergic neurons to their target, the striatum. Histological analysis demonstrates that these new axons achieve morphologically accurate reinnervation. In addition, functional reintegration into target circuitry is achieved, as indicated by partial behavioral recovery.

Interpretation:

We conclude that regrowth of axons within the adult nigrostriatal projection, a system that is prominently affected in Parkinson's disease, can be achieved by activation of Akt/mTor signaling in surviving endogenous mesencephalic dopaminergic neurons by viral vector transduction. ANN NEUROL 2011
Disparities in stroke incidence contributing to disparities in stroke mortality
Authors: Howard Virginia J. , Kleindorfer Dawn O. , Judd Suzanne E. , McClure Leslie A. , Safford Monika M. , Rhodes J. David , Cushman Mary , Moy Claudia S. , Soliman Elsayed Z. , Kissela Brett M. , Howard George
Published: January 2011

Objective:

While black‐white and regional disparities in U.S. stroke mortality rates are well documented, the contribution of disparities in stroke incidence is unknown. We provide national estimates of stroke incidence by race and region, contrasting these to publicly available stroke mortality data.

Methods:

This analysis included 27,744 men and women without prevalent stroke (40.4% black), aged ≥45 years from the REasons for Geographic And Racial Differences in Stroke (REGARDS) national cohort study, enrolled 2003–2007. Incident stroke was defined as first occurrence of stroke over 4.4 years of follow‐up. Age‐sex–adjusted stroke mortality rates were calculated using data from the Centers for Disease Control and Prevention (CDC) Wide‐Ranging Online Data for Epidemiological Research (WONDER) System.

Results:

There were 460 incident strokes over 113,469 person‐years of follow‐up. Relative to the rest of the United States, incidence rate ratios (IRRs) of stroke in the southeastern stroke belt and stroke buckle were 1.06 (95% confidence interval [CI], 0.87–1.29) and 1.19 (95% CI, 0.96–1.47), respectively. The age‐sex–adjusted black/white IRRblack was 1.51 (95% CI, 1.26–1.81), but for ages 45–54 years the IRRblack was 4.02 (95% CI, 1.23–13.11) while for ages 85+ it was 0.86 (95% CI, 0.33–2.20). Generally, the IRRsblack were less than the mortality rate ratios (MRRs) across age groups; however, only in ages 55–64 years and 65–74 years did the 95% CIs of IRRsblack not include the MRRblack. The MRRs for regions were within 95% CIs for IRRs.

Interpretation:

National patterns of black‐white and regional differences in stroke incidence are similar to those for stroke mortality; however, the magnitude of differences in incidence appear smaller. ANN NEUROL 2011
Passive F+‐Oxidationsmittel ermöglichen die selektive reduktive Eliminierung hochvalenter Metallzentren in der Katalyse
Authors: Engle Keary M. , Mei Tian‐Sheng , Wang Xisheng , Yu Jin‐Quan
Published: January 2011

Die reduktive Eliminierung teils oder vollständig oxidierter Metallzentren ist ein wichtiger Schritt in einer Unzahl von C‐C‐ und C‐Heteroatom‐Bindungsbildungen. Eine Möglichkeit, anspruchsvolle reduktive Eliminierungen zu erleichtern, besteht in der Oxidation der Metallzentren durch Zwei‐Elektronen‐Oxidationsmittel (also von Mn zu Mn+2). Viele der für diese Umwandlung typischen Oxidationsmittel enthalten allerdings Sauerstoff‐, Stickstoff‐ oder Halogenatome — die sich anschließend an der reduktiven Eliminierung beteiligen könnten —, sodass ein Produktgemisch entstehen würde. In diesem Kurzaufsatz beschreiben wir die Untersuchungen zu einem neuartigen Lösungsansatz für dieses verbreitete Problem in der metallorganischen Chemie: die Verwendung von passiven F+‐Oxidationsmitteln sowie die jüngsten Anwendungen in PdII/PdIV‐ und AuI/AuIII‐Katalysen. Außerdem besprechen wir kurz ein seltenes Beispiel, in dem die Verwendung eines Ein‐Elektronen‐Oxidationsmittels zur Begünstigung einer selektiven reduktiven Eliminierung bei Palladium(II)‐katalysierten C‐H‐Funktionalisierungen gezeigt werden konnte; dies sehen wir als eine vielversprechende Richtung für zukünftige Anwendungen auf diesem Gebiet an.
Anatomical Sciences Education Vol. 4, Issue 1, 2011 Cover Image
Authors: Richardson April , Hazzard Matthew , Challman Sandra D. , Morgenstein Aaron M. , Brueckner Jennifer K.
Published: January 2011

The University of Kentucky College of Medicine has established a presence in “Second Life” by developing a virtual anatomy laboratory. This virtual facility has a variety of stations and is being used in the educational programs in anatomy for undergraduate and health professional students. In the screen capture on the cover, avatars, representing instructors and students, are reviewing anatomy assignments during a session in the virtual laboratory. A description of this “Second life” virtual laboratory and its educational opportunities is found in the article by Dr. Richardson and her colleagues in the current issue of ASE.
Control of the Solid‐State Chiral Optical Properties of a Supramolecular Organic Fluorophore Containing 4‐(2‐Arylethynyl)‐Benzoic Acid
Authors: Nishiguchi Noriaki , Kinuta Takafumi , Nakano Yoko , Harada Takunori , Tajima Nobuo , Sato Tomohiro , Fujiki Michiya , Kuroda Reiko , Matsubara Yoshio , Imai Yoshitane
Published: January 2011

The solid‐state chiral optical properties of a 4‐(2‐arylethynyl)‐benzoic acid/amine supramolecular organic fluorophore can be controlled by changing the arylethynyl group of the achiral 4‐(2‐arylethynyl)‐benzoic acid component molecule rather than the chirality of the amine component molecule.
Externalities Awareness in Anticommons Dilemmas Decreases Defective Behavior
Authors: Dhont Kristof , Van Hiel Alain , De Cremer David
Published: January 2011

The present paper explores the effect of the salience of collective consequences of opportunistic behavior in commons and anticommons dilemmas. Making this type of externalities salient was expected to increase the awareness of the conflict between collective and personal interests, especially in the anticommons dilemma. The results of a vignette study (Study 1, N = 100) and a laboratory experiment (Study 2, N = 55) confirmed our hypotheses, revealing more opportunistic behavior in the anticommons than in the commons dilemma when externalities were not made salient, while no significant dilemma effect was obtained when the externalities were made salient. Moreover, the results of Study 2 demonstrated that the dilemma effect on cooperation was mediated by externalities awareness. The positive effects of increments in externalities awareness on cooperation are discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of postconditioning on mitochondrial dysfunction in experimental aortic cross-clamping
Authors: Charles A-L , Guilbert A-S , Bouitbir J , Goette-Di Marco P , Enache I , Zoll J , Piquard F , Geny B
Published: January 2011

Background

Cross-clamping of the aorta during abdominal aortic aneurysm surgery induces muscle ischaemia with resultant morbidity. This study tested whether ischaemic postconditioning would decrease mitochondrial dysfunction in skeletal muscle by reducing oxidative stress.

Methods

Three groups (9 rats each) underwent surgery, including a control group without ischaemia and an ischaemia–reperfusion group that had 3 h ischaemia induced by aortic clamping and collateral vessel ligation, followed by 2 h of reperfusion. The third group had ischaemia for 3 h then underwent postconditioning comprising three short intervals of ischaemia–reperfusion at the onset of reperfusion. Activity of complexes I, II, III and IV of the mitochondrial respiratory chain was monitored in gastrocnemius muscle, along with oxidative stress measured by dihydroethidium (DHE) staining and antioxidant defence determined by measurement of glutathione levels.

Results

Ischaemia–reperfusion alone caused a significant reduction in maximal oxidative capacity (−31·8 per cent; P = 0·002), activity of complexes II, III and IV (−34·5 per cent; P = 0·007) and complex IV activity (−30·6 per cent; P = 0·039). It also increased reactive oxygen species (DHE staining increased to 223·1 per cent of control value; P = 0·027) and reduced antioxidant defence (glutathione level − 28·6 per cent; P = 0·039). Postconditioning counteracted these deleterious effects by increasing mitochondrial complex I, II, III and IV activities, restoring muscle DHE staining and preserving glutathione content.

Conclusion

Ischaemic postconditioning protects skeletal muscle mitochondria against ischaemia–reperfusion injury by reducing oxidative stress and preserving antioxidant defence in an experimental model. Mitochondrial protection to reduce reperfusion injury in clinical vascular surgery may be warranted.
Enhanced Expression and Purification of Fungal Galactose Oxidase in Escherichia coli and Use for Analysis of a Saturation Mutagenesis Library
Authors: Deacon Sarah E. , McPherson Michael J.
Published: January 2011

Galactose oxidase (GO) displays broad primary alcohol substrate specificity and so offers potential for engineering new substrate specificity by directed evolution. Producing variant libraries of sufficient complexity ideally requires expression of functional protein in a host such as Escherichia coli. Wild‐type GO is produced by the fungus Fusarium graminiarum and is expressed poorly in E. coli. We introduced silent mutations within codons 2–7 of the mature GO coding sequence to enhance GO translation and have combined these with other expression‐enhancing mutations. We selected the best E. coli host strain, autoinduction medium, induction temperature, harvest time and cell lysis procedure to produce active recombinant GO. Although normally secreted by the fungus, we have expressed GO in the cytoplasm of E. coli and have used a C‐terminal Streptag II sequences for single‐step affinity purification. This resulted in purification of 240 mg of functional GO per litre of shake flask culture. We have generated a saturation mutagenesis library at residue Cys383, known to influence substrate binding, and have used the optimised expression conditions to purify and characterise the resulting enzymes.
Design and Control of a Fully Thermally Coupled Distillation Column Modified from a Conventional System
Authors: Hwang K. S. , Kim B. C. , Kim Y. H.
Published: January 2011

A modified fully thermally coupled distillation column is proposed, with utilization of the existing distillation columns of the conventional system, and its control scheme is suggested here. The proposed distillation system is applied to a benzene‐toluene‐xylene (BTX) separation process, of which the system design and control performance evaluation are conducted using the HYSYS software. The performance of the suggested 3 × 3 control is examined in the set‐point tracking of product specification and the regulation for the changes of feed flow and composition. The pairings of three proportional‐integral control loops are the reflux flow and the specification of overhead product, the prefractionator vapor flow and that of the side product, and the vapor boil‐up rate and that of the bottom product. The multi‐variable controllability using various indices is investigated for the proposed control scheme, and the controllability is compared with that of the cross‐pairing between the control loops of the side and bottom products.
Indirect Synthesis of Bis(2‐PhInd)ZrCl2Metallocene Catalyst, Kinetic Study and Modeling of Ethylene Polymerization
Authors: Ahmadjo S. , Arabi H. , Nekoomanesh M. , Mortazavi S. M. M. , Zohuri G. , Ahmadi M. , Bolandi S.
Published: January 2011

Bis(2‐phenylindenyl)zirconium dichloride (bis(2‐PhInd)ZrCl2) catalyst was synthesized via the preparation of bis(2‐phenylindenyl)zirconium dimethyl (bis(2‐PhInd)ZrMe2) followed by chlorination to obtain the catalyst. Performance of the catalyst for ethylene polymerization and its kinetic behavior were investigated. Activity of the catalyst increased as the [Al]:[Zr] molar ratio increased to 2333:1, followed by reduction at higher ratios. The maximum activity of the catalyst was obtained at a polymerization temperature of 60 °C. The rate‐time profile of the reaction was of a decay type under all conditions. A general kinetic scheme was modified by considering a reversible reaction of latent site formation, and used to predict dynamic polymerization rate and viscosity average molecular weight of the resulting polymer. Kinetic constants were estimated by the Nelder‐Mead numerical optimization algorithm. It was shown that any deviation from the general kinetic behavior can be captured by the addition of the reversible reaction of latent site formation. Simulation results were in satisfactory agreement with experimental data.
Computational Fluid Dynamics Simulation of Pilot‐Plant‐Scale Two‐Phase Separators
Authors: Pourahmadi Laleh A. , Svrcek W. Y. , Monnery W. D.
Published: January 2011

Two computational fluid dynamics (CFD) modeling approaches, the discrete phase model (DPM) and the combination of volume of fluid (VOF) and DPM, are developed to simulate the phase separation phenomenon in four pilot‐plant‐scale separators. The incipient vapor phase velocity, at which liquid droplet carryover occurs, and separation efficiency plots are used as criteria for evaluating the developed CFD models. The simulation results indicate that the VOF‐DPM approach is a substantial modification to the DPM approach in terms of the predicted separation efficiency data and diagrams. CFD simulation profiles demonstrate that all the separators are essentially operating at a constant pressure. The CFD results also show that mist eliminators may operate more efficiently in horizontal separators than in vertical separators.
Analysis of Methanol Production from Biomass Gasification
Authors: Feng W. , Ji P. , Chen B. , Zheng D.
Published: January 2011

A biomass‐based methanol production process was investigated. The process consists of a biomass gasifier, steam reformer, and methanol synthesis reactor as the main units. Reactors were simulated by applying the kinetic models previously developed and the process was analyzed based on the simulation results. The key parameters, the equivalence ratio in biomass gasification, the temperature in steam reforming, and the recycle of hydrogen in methanol synthesis were identified. These parameters affect the methanol production. The process analysis indicates that the optimal combinations of the parameters can greatly enhance the methanol production and the thermodynamic efficiency. Finally, the elemental analysis for carbon and hydrogen along the process was carried out.
“Click” Immobilization on Alkylated Silicon Substrates: Model for the Study of Surface Bound Antimicrobial Peptides
Authors: Li Yan , Santos Catherine M. , Kumar Amit , Zhao Meirong , Lopez Analette I. , Qin Guoting , McDermott Alison M. , Cai Chengzhi
Published: January 2011

We describe an effective approach for the covalent immobilization of antimicrobial peptides (AMPs) to bioinert substrates via CuI‐catalyzed azide–alkyne cycloaddition (CuAAC). The bioinert substrates were prepared by surface hydrosilylation of oligo(ethylene glycol) (OEG) terminated alkenes on hydrogen‐terminated silicon surfaces. To render the OEG monolayers “clickable”, mixed monolayers were prepared using OEG‐alkenes with and without a terminal alkyne protected by a trimethylgermanyl (TMG) group. The mixed monolayers were characterized by X‐ray photoelectron spectroscopy (XPS), elliposometry and contact angle measurement. The TMG protecting group can be readily removed to yield a free terminal alkyne by catalytic amounts of CuI in an aqueous media. This step can then be combined with the subsequent CuAAC reaction. Thus, the immobilization of an azide modified AMP (N3‐IG‐25) was achieved in a one‐pot deprotection/coupling reaction. Varying the ratio of the two alkenes in the deposition mixture allowed for control over the density of the alkynyl groups in the mixed monolayer, and subsequently the coverage of the AMPs on the monolayer. These samples allowed for study of the dependence of antimicrobial activities on the AMP density. The results show that a relative low coverage of AMPs (∼1.6×1013 molecule per cm2) is sufficient to significantly suppress the viability of Pseudomonas aeruginosa, while the surface presenting the highest density of AMPs (∼2.8×1013 molecule per cm2) is still cyto‐compatible. The remarkable antibacterial activity is attributed to the long and flexible linker and the site‐specific “click” immobilization, which may facilitate the covalently attached peptides to interact with and disrupt the bacterial membranes.
Selection of G‐Quadruplex Folding Topology with LNA‐Modified Human Telomeric Sequences in K+ Solution
Authors: Pradhan Devranjan , Hansen Lykke H. , Vester Birte , Petersen Michael
Published: January 2011

G‐rich nucleic acid oligomers can form G‐quadruplexes built by G‐tetrads stacked upon each other. Depending on the nucleotide sequence, G‐quadruplexes fold mainly with two topologies: parallel, in which all G‐tracts are oriented parallel to each other, or antiparallel, in which one or more G‐tracts are oriented antiparallel to the other G‐tracts. In the former topology, all glycosidic bond angles conform to anti conformations, while in the latter topology they adopt both syn and anti conformations. It is of interest to understand the molecular forces that govern G‐quadruplex folding. Here, we approach this problem by examining the impact of LNA (locked nucleic acid) modifications on the folding topology of the dimeric model system of the human telomere sequence. In solution, this DNA G‐quadruplex forms a mixture of G‐quadruplexes with antiparallel and parallel topologies. Using CD and NMR spectroscopies, we show that LNA incorporations can modulate this equilibrium in a rational manner and we establish a relationship between incorporation of LNA nucleotides in syn and/or anti positions and the shift of the equilibrium to obtain exclusively the parallel G‐quadruplex. The change in topology is driven by a combination of the C3′‐endo puckering of LNA nucleotides and their preference for the anti glycosidic conformation. In addition, the parallel LNA‐modified G‐quadruplexes are thermally stabilised by about 11 °C relative to their DNA counterparts.
Electron‐Accepting Dithiarubicene (Emeraldicene) and Derivatives Prepared by Unprecedented Nucleophilic Hydrogen Substitution by Alkyllithium Reagents
Authors: Mohebbi Ali Reza , Wudl Fred
Published: January 2011

By understanding the role of DMF as a hydride source via a Pd‐catalyzed reaction and switching to CH3CN solvent, an efficient route for the synthesis of emeraldicene and some new substituted derivatives is reported with potential application in organic electronics. Additionally, the nucleophilic alkylation of emeraldicene 4 a with alkyllithium reagents provides monosubstituted compounds 7 a and 7 b, the latter crystallizing in columnar stacks, with π–π overlap between adjacent molecules in the stack.
2′‐O,4′‐C‐Aminomethylene‐Bridged Nucleic Acid Modification with Enhancement of Nuclease Resistance Promotes Pyrimidine Motif Triplex Nucleic Acid Formation at Physiological pH
Authors: Torigoe Hidetaka , Rahman S. M. Abdur , Takuma Hiroko , Sato Norihiro , Imanishi Takeshi , Obika Satoshi , Sasaki Kiyomi
Published: January 2011

Due to the instability of pyrimidine motif triplex DNA at physiological pH, triplex stabilization at physiological pH is crucial in improving its potential in various triplex‐formation‐based strategies in vivo, such as gene expression regulation, genomic DNA mapping, and gene‐targeted mutagenesis. To this end, we investigated the thermodynamic and kinetic effects of our previously reported chemical modification, 2′‐O,4′‐C‐aminomethylene‐bridged nucleic acid (2′,4′‐BNANC) modification of triplex‐forming oligonucleotide (TFO), on triplex formation at physiological pH. The thermodynamic analyses indicated that the 2′,4′‐BNANC modification of TFO increased the binding constant of the triplex formation at physiological pH by more than 10‐fold. The number and position of the 2′,4′‐BNANC modification in TFO did not significantly affect the magnitude of the increase in the binding constant. The consideration of the observed thermodynamic parameters suggested that the increased rigidity and the increased degree of hydration of the 2′,4′‐BNANC‐modified TFO in the free state relative to the unmodified TFO may enable the significant increase in the binding constant. Kinetic data demonstrated that the observed increase in the binding constant by the 2′,4′‐BNANC modification resulted mainly from the considerable decrease in the dissociation rate constant. The TFO stability in human serum showed that the 2′,4′‐BNANC modification significantly increased the nuclease resistance of TFO. Our results support the idea that the 2′,4′‐BNANC modification of TFO could be a key chemical modification to achieve higher binding affinity and higher nuclease resistance in the triplex formation under physiological conditions, and may lead to progress in various triplex‐formation‐based strategies in vivo.
Total Synthesis and Biological Assessment of (−)‐Exiguolide and Analogues
Authors: Fuwa Haruhiko , Suzuki Takaya , Kubo Hiroshi , Yamori Takao , Sasaki Makoto
Published: January 2011

We describe herein an enantioselective total synthesis of (−)‐exiguolide, the natural enantiomer. The methylene bis(tetrahydropyran) substructure was efficiently synthesized by exploiting olefin cross‐metathesis for the assembly of readily available acyclic segments and intramolecular oxa‐conjugate cyclization and reductive etherification for the formation of the tetrahydropyran rings. The 20‐membered macrocyclic framework was constructed in an efficient manner by means of Julia–Kocienski coupling and Yamaguchi macrolactonization. Finally, the (E,Z,E)‐triene side chain was introduced stereoselectively via Suzuki–Miyaura coupling to complete the total synthesis. Assessment of the growth inhibitory activity of synthetic (−)‐exiguolide against a panel of human cancer cell lines elucidated for the first time that this natural product is an effective antiproliferative agent against the NCI‐H460 human lung large cell carcinoma and the A549 human lung adenocarcinoma cell lines. Moreover, we have investigated structure–activity relationships of (−)‐exiguolide, which elucidated that the C5‐methoxycarbonylmethylidene group and the length of the side chain are important for the potent activity.
Catalyst Tests on a Pilot Plant for Small Biomass Combustion Systems
Authors: Hartmann Ingo , Lenz Volker , Schenker Marian , Thiel Christian , Einicke Wolf‐Dietrich , Bindig René , Roland Ulf
Published: January 2011

Eine katalytisch unterstützte Emissionsminderung an Biomasse‐Kleinfeuerungen kann zusätzlich zur Reduzierung von Feinstaub eine Umwandlung von toxischen organischen Komponenten zu Kohlendioxid und Wasser ermöglichen. Für Katalysatoruntersuchungen unter Praxisbedingungen wurde eine spezielle Versuchsanlage aufgebaut. Die Ergebnisse zeigen, dass Produkte der unvollständigen Verbrennung aus Kaminöfen, wie Kohlenmonoxid, durch katalytische Verfahren abgebaut werden können. Weitere Entwicklungsarbeiten und Untersuchungen sind jedoch notwendig, um die angestrebten Emissionsgrenzwerte zu erreichen.
Energy‐Saving Grinding of Grain with a Wedge‐Shaped Discs Mill
Authors: Hoffmann Thomas , Fürll Christian , Hempel Heinz
Published: January 2011

Für die Zerkleinerung von Futtergetreide wurde ein Keilscheibenzerkleinerer entwickelt und untersucht. Die Untersuchungen erfolgten an Weizen, Roggen und Gerste in einem Kornfeuchtebereich bis 21 %. Die Ergebnisse zeigen, dass Keilscheiben mit kreisbogenförmigen Schneidkanten hohe Masseströme von über 40 t h–1 bei einem Energiebedarf von weniger als 3 kWh t–1 ermöglichen. Die Kornfeuchte hat wenig Einfluss auf den Energiebedarf.
The Oblique Impact of Three Different Types of Granules
Authors: Müller Peter , Horbach Siarhei , Antonyuk Sergiy , Heinrich Stefan , Tomas Jürgen
Published: January 2011

Der schiefe Stoßvorgang von dominant elastischen γ‐Al2O3‐, elastisch‐plastischen Zeolith 4A‐ und dominant plastischen Natriumbenzoatgranulaten wurde mit einer Fallapparatur experimentell ermittelt. Die normale und tangentiale Stoßzahl bei verschiedenen Aufprallwinkeln wurde bestimmt und mit Ergebnissen aus einer dimensionslosen Analyse bestätigt.
High Pressure Optical Cell for Studies of the Ammonothermal Process
Authors: Alt Nicolas S. A. , Schlücker Eberhard
Published: January 2011

Die ammonothermale Züchtung von Galliumnitrid‐Halbleitereinkristallen hat in den letzten Jahren enorme technologische Fortschritte erfahren. Die Vorgänge bei der Reaktion sind jedoch noch kaum verstanden, da wegen der extremen Reaktionsbedingungen nur indirekte Verfahren zur Bestimmung von Gleichgewichts‐ und Löslichkeitsdaten angewendet werden konnten. Mit dieser Arbeit wird eine Hochdruck‐Sichtzelle vorgestellt, an der In‐situ‐Untersuchungen am ammonothermalen System unter realen Reaktionsbedingungen durchgeführt wurden.
Biodistribution and Photodynamic Efficacy of a Water‐Soluble, Stable, Halogenated Bacteriochlorin against Melanoma
Authors: Dąbrowski Janusz M. , Urbanska Krystyna , Arnaut Luis G. , Pereira Mariette M. , Abreu Artur R. , Simões Sérgio , Stochel Grażyna
Published: January 2011

The in vitro phototoxicity of a photostable, synthetic, water‐soluble, halogenated bacteriochlorin, 5,10,15,20‐tetrakis(2‐chloro‐5‐sulfophenyl)bacteriochlorin (TCPBSO3H), toward mouse melanoma (S91) cells is ∼60‐fold higher than that of the analogous porphyrin, and is associated with very weak toxicity in the dark; 90 % of S91 cells were killed in response to a light dose of 0.26 J cm−2 in the presence of [TCPBSO3H]=5 μM. In vivo toxicity toward DBA mice is very low, even at doses of 20 mg kg−1. In vivo pharmacokinetics and biodistribution of TCPBSO3H were studied in DBA mice with S91 tumors; 24 h after intraperitoneal injection of 10 mg kg−1, TCPBSO3H demonstrated preferential accumulation in S91 mouse melanoma, with tumor‐to‐normal tissue ratios of 3 and 5 for muscle and skin, respectively. Photodynamic therapy (PDT) performed under these conditions, with 90 mW cm−2 diode laser irradiation at λ 750 nm for 20 min (total light dose of 108 J cm−2), resulted in tumor regression. Tumor recurrence was observed only approximately two months after treatment, confirming the efficacy of this PDT against melanoma.
Intensity‐modulated radiation therapy reduces radiation‐induced trismus in patients with nasopharyngeal carcinoma
Authors: Chen Yuan‐Yuan , Zhao Chong , Wang Jin , Ma Hong‐Lian , Lai Shu‐Zheng , Liu Yuan , Han Fei , Lu Li‐Xia , Bao Yong , Chen Ming
Published: January 2011

BACKGROUND:

Intensity‐modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC) provides better temporomandibular joint (TMJ) sparing and, thus, may reduce the incidence of radiation‐induced trismus after radiotherapy. The objectives of this study were to evaluate radiation‐induced trismus in patients with NPC who had received IMRT and to assess the pretreatment factors, relevant treatment factors, and dosimetry parameters associated with trismus.

METHODS:

A prospective, single‐arm measurement study with more than 5 years of follow‐up was designed. Patients with newly diagnosed stage I through IVB NPC who received treatment with IMRT were eligible. Patients received 66 to 70 grays (Gy) to the gross tumor volume. The maximal interincisal distance (MID) was measured at baseline and 6 months, 1 year, 2 years, 3 years, 4 years, and 5 years after they completed IMRT.

RESULTS:

The trial enrolled 211 consecutive patients from 2001 to 2004. The mean dose to the TMJ ranged from 6.18 Gy to 51.36 Gy (median dose, 29.88 Gy). Compared with baseline MID levels, normalized MID levels at 6 months, 1 year, 2 years, 3 years, 4 years, and 5 years after IMRT were 94.6% ± 9.9%, 92.5% ± 10.5%, 92% ± 10.6%, 92.2% ± 10.5%, 92.1% ± 10.2%, and 90.3% ± 11.4%, respectively (P < .001). According to a revised subjective‐objective management‐analytical (SOMA) scale, grade 1/2 trismus was identified in 12 of 211 patients (5.7%), and no grade 3/4 trismus was observed. There was an increasing risk of trismus after IMRT when the MID was <40.5 mm at baseline compared with an MID >40.5 mm (P = .007). No dosimetric parameter was associated with trismus.

CONCLUSIONS:

IMRT was able to reduce the radiation dose to the TMJ and likely reduced the incidence and severity of radiation‐induced trismus after radiotherapy. Cancer 2011. © 2011 American Cancer Society.
Minimal social network effects evident in cancer screening behavior
Authors: Keating Nancy L. , O'Malley A. James , Murabito Joanne M. , Smith Kirsten P. , Christakis Nicholas A
Published: January 2011

BACKGROUND:

Social networks may influence screening behaviors. We assessed whether screening for breast, prostate, or colorectal cancer is influenced by the actual screening behaviors of siblings, friends, spouses, and coworkers.

METHODS:

We conducted an observational study using Framingham Heart Study data to assess screening for eligible individuals during the late 1990s. We used logistic regression to determine whether the probability of screening for breast, prostate, or colorectal cancer was influenced by the proportion of siblings, friends, and coworkers who had the same screening, as well as spouse's screening for colorectal cancer, adjusting for other factors that might influence screening rates.

RESULTS:

Among 1660 women aged 41‐70 years, 71.7% reported mammography in the previous year; among 1217 men aged 51‐70 years, 43.3% reported prostate‐specific antigen testing in the previous year; and among 1426 men and women aged 51‐80 years, 46.9% reported stool blood testing and/or sigmoidoscopy in the previous year. An increasing proportion of sisters who had mammography in the previous year was associated with mammography screening in the ego (odds ratio [OR], 1.034; 95% confidence interval [CI], 1.000‐1.065 for each 10% increase). A spouse with recent screening was associated with more colorectal cancer screening (OR, 1.65; 95% CI, 1.39‐1.98 vs unmarried). Otherwise, screening behaviors of siblings, friends, and coworkers were not associated with screening in the ego.

CONCLUSIONS:

Aside from a slight increase in breast cancer screening among women whose sisters were screened and colorectal cancer screening if spouses were screened, the screening behavior of siblings, friends, or coworkers did not influence cancer screening behaviors. Cancer 2011. © 2011 American Cancer Society.
Effects of individual‐level socioeconomic factors on racial disparities in cancer treatment and survival
Authors: Du Xianglin L. , Lin Charles C. , Johnson Norman J. , Altekruse Sean
Published: January 2011

BACKGROUND:

This is the first study to use the linked National Longitudinal Mortality Study and Surveillance, Epidemiology, and End Results (SEER) data to determine the effects of individual‐level socioeconomic factors (health insurance, education, income, and poverty status) on racial disparities in receiving treatment and in survival.

METHODS:

This study included 13,234 cases diagnosed with the 8 most common types of cancer (female breast, colorectal, prostate, lung and bronchus, uterine cervix, ovarian, melanoma, and urinary bladder) at age ≥25 years, identified from the National Longitudinal Mortality Study‐SEER data during 1973 to 2003. Kaplan‐Meier methods and Cox regression models were used for survival analysis.

RESULTS:

Three‐year all‐cause observed survival for cases diagnosed with local‐stage cancers of the 8 leading tumors combined was ≥82% regardless of race/ethnicity. More favorable survival was associated with higher socioeconomic status. Compared with whites, blacks were less likely to receive first‐course cancer‐directed surgery, perhaps reflecting a less favorable stage distribution at diagnosis. Hazard ratio (HR) for cancer‐specific mortality was significantly higher among blacks compared with whites (HR, 1.2; 95% confidence interval [CI], 1.1‐1.3) after adjusting for age, sex, and tumor stage, but not after further controlling for socioeconomic factors and treatment (HR, 1.0; 95% CI, 0.9‐1.1). HRs for all‐cause mortality among patients with breast cancer and for cancer‐specific mortality in patients with prostate cancer were significantly higher for blacks compared with whites after adjusting for socioeconomic factors, treatment, and patient and tumor characteristics.

CONCLUSIONS:

Favorable survival was associated with higher socioeconomic status. Racial disparities in survival persisted after adjusting for individual‐level socioeconomic factors and treatment for patients with breast and prostate cancer. Cancer 2011. © 2011 American Cancer Society.
DNA repair gene polymorphisms and benefit from gefitinib in never‐smokers with lung adenocarcinoma
Authors: Han Ji‐Youn , Yoon Kyong‐Ah , Park Jae Hee , Lee Young Joo , Lee Geon Kook , Han Jong Hee , Yoon Sung Jin , Yun Tak , Kim Heung Tae , Lee Jin Soo
Published: January 2011

BACKGROUND:

The objective of this study was to investigate whether polymorphisms in DNA repair genes affect clinical outcome of never‐smokers with lung adenocarcinoma (NSLA).

METHOD:

Common polymorphisms in the DNA repair genes ribonucleotide reductase M1 (RRM1), excision repair cross‐complementation group 1 (ERCC1), and x‐ray repair cross‐complementing group 1 (XRCC1) were genotyped in DNA samples from 158 patients among 313 NSLA who were randomized to receive either gefitinib or gemcitabine plus cisplatin (GP) as first‐line therapy. Immunohistochemistry for ERCC1 (n = 38) and direct sequencing of the epidermal growth factor gene (EGFR) (n = 42) were performed using tumor samples.

RESULTS:

Patients who had the XRCC1 arginine (Arg)/Arg polymorphism at codon 399 (399Arg/Arg) had a higher response rate to gefitinib (71% vs 36%; P = .002) and had more EGFR‐mutant tumors (82% vs 29%; P = .001) than patients who had the glutamine (Gln) allele. Patients who had the ERCC1 adenine‐adenine (AA) polymorphism at codon 8092 (8092AA) had a higher response to GP than patients who had the cytosine‐cytosine (CC) or the CA genotype (100% vs 44%; P = .043).When gefitinib was compared with GP, significantly longer progression‐free survival (PFS) was observed with gefitinib among patients who had the XRCC1 399Arg/Arg genotype (7.5 months vs 6.6 months; P = .013), the RRM1 2464 guanine‐guanine (GG) genotype (11.5 months vs 6.0 months; P = .004), and the ERCC1 8092CA genotype (7.5 months vs 6.4 months; P = .024). When the 3 genotypes were analyzed jointly, significantly longer PFS was observed with gefitinib among patients who had ≥2 genotypes (8.1 months vs 6.4 months; P = .009), whereas a trend for longer PFS was observed with GP among patients without the 3 genotypes (6.3 months vs 2.0 months; P = .06). In a multivariate Cox regression model, the greater number of specific genotypes independently predicted improved overall survival (hazard ratio, 0.5; 95% confidence interval, 0.3‐0.8; P = .006).

CONCLUSIONS:

Patients with the XRCC1 399Arg/Arg, RRM1 2464GG, and ERCC1 8092CA genotypes did benefit from gefitinib. Having more of these genotypes may predict favorable prognosis for NSLA. Cancer 2011. © 2011 American Cancer Society.