bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unstable and Oscillatory Behaviour in Heterogeneous Catalysis
Authors: Wicke E. , Kummann P. , Keil W. , Schiefler J. 
Published: December 2010

AbstractWith two examples, the oxidation of H2 and CO on Pt carrier catalysts, it is shown that special states of chemisorption and kinetics of surface processes can create periodicity and bistable behaviour of catalytic reactions. The (nonisothermal) oscillations of the H2 oxidation can be traced back to the superposition of a slow oxidation‐reduction process under participation of an active and an inactive (blocking) chemisorption species of oxygen, in agreement with TDS measurements. By means of a stability analysis, based on the linearized balance equations, the main features of the oscillatory behaviour can be explained. — With the CO oxidation oscillations under isothermal conditions have been studied that appear as precursors to a quenching of the reaction. A periodic change of the CO coverage (blocking) of the catalyst surface was demonstrated. For the formation of the CO coverage via CO clusters on the surface, in the sense of dissipative structures, a mechanism with co‐operation of the chemisorption process and the LH‐reaction is shown up. The periodic reactivation of the surface is attributed to the increase of desorption probability (decrease of desorption energy) with increasing packing density of the CO. A quantitative treatment, however, is not yet possible at present, because relationships for the kinetics of non‐random distributions on surface sites are missing.
Feedback Kinetics in Physicochemical Oscillators
Authors: Franck U. F. 
Published: December 2010

AbstractAnalogously to feedback mechanisms in electrical networks kinetical self‐influence of chemical reactions and physicochemical transportation processes may lead under certain conditions to oscillations, bistability, triggerability, reaction propagation and other temporal coupling phenomena. It is shown that all of these phenomena including dissipative structures can be interpreted and classified kinetically on the basis of positive, negative and antagonistic feedback.
Contribution to the Chemistry of the Belousov‐Zhabotinskii (BZ) Type Reactions
Authors: Noszticzius Zoltán , Bódiss János 
Published: December 2010

AbstractFour new experimental observations are discussed which are difficult to interpret if we regard the bromide ion as a control intermediate of the BZ reaction. To explain the experimental facts two new hypothetical models: the bromine controlled (BC) model of the heterogeneous oscillations (substrate oxalic acid) and the Lotka‐Volterra (LV) model of the homogeneous oscillations with mixed substrate (oxalic acid‐aceton) are presented. Some variations of the more realistic LV model are mentioned.
Über die kinetischen Instabilitäten bei der CO‐Oxidation an Platin‐Katalysatoren
Authors: Keil W. , Wicke E. 
Published: December 2010

AbstractBei der CO‐Oxidation an Pt‐Katalysatoren werden unter isothermen Bedingungen sprunghaftes „Zünden”︁ und „Löschen”︁ der Reaktion sowie Oszillationen des Umsatzes beobachtet. Diese kinetischen Instabilitäten werden an einem Pt‐Trägerkontakt in einer Strömungsapparatur unter Normaldruck zwischen 100 und 300°C untersucht. Sie treten bei mittleren CO‐Gehalten von einigen Zehntel % bis einigen % CO in Luft auf. Für kleinere und höhere CO‐Gehalte kann die Kinetik der Reaktion durch einen einheitlichen Langmuir‐Hinshelwood‐Ansatz beschrieben werden, der die unterschiedlichen Chemisorptionszentren für CO und O2 auf der Pt‐Oberfläche berücksichtigt. Im mittleren Bereich wird mit einer speziell entwickelten Versuchstechnik eine reversible CO‐Blockierung der Pt‐Oberfläche als Ursache des instabilen Verhaltens der Reaktion festgestellt.
Folate pathway and nonsyndromic cleft lip and palate
Authors: Blanton Susan H. , Henry Robin R. , Yuan Quiping , Mulliken John B. , Stal Samuel , Finnell Richard H. , Hecht Jacqueline T. 
Published: December 2010

AbstractBACKGROUNDNonsyndromic cleft lip with or without cleft palate (NSCLP) is a common complex birth defect. Periconceptional supplementation with folic acid, a key component in DNA synthesis and cell division, has reduced the birth prevalence of neural tube defects and may similarly reduce the birth prevalence of other complex birth defects including NSCLP. Past studies investigating the role of two common methylenetetrahydrofolate reductase (MTHFR) single‐nucleotide polymorphisms (SNPs), C677T (rs1801133) and A1298C (rs1801131), in NSCLP have produced conflicting results. Most studies of folate pathway genes have been limited in scope, as few genes/SNPs have been interrogated. Here, we asked whether variations in a more comprehensive group of folate pathway genes were associated with NSCLP, and were there detectable interactions between these genes and environmental exposures? METHODS: Fourteen folate metabolism‐related genes were interrogated using 89 SNPs in multiplex and simplex non‐Hispanic white and Hispanic NSCLP families. RESULTS: Evidence for a risk association between NSCLP and SNPs in NOS3 and TYMS was detected in the non‐Hispanic white group, whereas associations with MTR, BHMT2, MTHFS, and SLC19A1 were detected in the Hispanic group. Evidence for over‐transmission of haplotypes and gene interactions in the methionine arm was detected.CONCLUSIONSThese results suggest that perturbations of the genes in the folate pathway may contribute to NSCLP. There was evidence for an interaction between several SNPs and maternal smoking, and for one SNP with gender of the offspring. These results provide support for other studies that suggest that high maternal homocysteine levels may contribute to NSCLP and should be further investigated. Birth Defects Research (Part A), 2011. © 2010 Wiley‐Liss, Inc.
Überblick über Regelungen zu Beton mit rezyklierter Gesteinskörnung
Authors: Hoffmann Cathleen , Jacobs Frank 
Published: December 2010

AbstractUnter dem Aspekt der Nachhaltigkeit gewinnt die Verwendung rezyklierter Gesteinskörnung in der Betonindustrie zunehmend an Bedeutung, weshalb sowohl national als auch international Merkblätter und Normen geschaffen werden. Nachfolgend wird ein Überblick über diese Regelungen gegeben und Übereinstimmungen, Widersprüche und Wissenslücken aufgezeigt. Es wird vor allem auf europäische Länder eingegangen, da diese mehrheitlich die europäischen Normen (CEN) verwenden.
Feuchtesensoren in der Bauwerksüberwachung
Authors: Sodeikat Christian 
Published: December 2010

AbstractDie Bestimmung des Wassergehalts und insbesondere der orts‐ und zeitabhängigen Feuchteverteilung in Baustoffen hat in der Forschung, Baustoffentwicklung, Bauwerksdiagnose und Bauwerksüberwachung einen besonderen Stellenwert. Bei der Untersuchung von Schadensursachen muss an Bauwerken in der Regel die Baustofffeuchte mit bewertet werden, da sowohl wesentliche Baustoffeigenschaften als auch die Dauerhaftigkeit von Bauwerken in entscheidendem Maße von deren Wassergehalt abhängig sind. In jüngster Zeit werden Feuchtesensoren eingesetzt, um die Funktionsfähigkeit und Dauerhaftigkeit von Instandsetzungs‐ bzw. Schutzmaßnahmen zu kontrollieren. Dies soll es dem Bauherrn ermöglichen, rechtzeitig Maßnahmen einleiten zu können, bevor Schäden infolge von Wasser‐ bzw. Chloridzutritt auftreten können.Condition Assessment with Moisture SensorsThe determination of the water content in construction materials and in particular with regard to its depth and time dependent distribution is of high interest in the area of research, material development and condition assessment of structures. The assessment of the reason of damages mostly require to regard the moisture content of structures, because the moisture content basically affects material properties and the durability of structures. Recently moisture sensors have been used to control the functionality and durability of repair and protection measures. This enables the owner to carry out accurately timed measures to prevent damages due to the ingress of water and chlorides.
Verifizierung moderner zerstörungsfreier Prüfverfahren an einem Abbruchbauwerk
Authors: Taffe Alexander , Hillemeier Bernd , Walther Andrei 
Published: December 2010

AbstractDie Entwicklung zerstörungsfreier Prüfverfahren im Bauwesen (ZfPBau‐Verfahren) hat in den letzten Jahren zu einer rasanten Leistungssteigerung geführt. Etliche Verfahren haben das Potenzial, in der Zukunft vom “Stand der Wissenschaft” zum “Stand der Technik” zu werden. Damit dies geschieht, muss möglichen Kunden vermittelt werden, welche Prüfaufgabe mit welchem Verfahren bearbeitet werden kann und wie zuverlässig die Ergebnisse sind. Um die Leistungsfähigkeit von ZfPBau‐Verfahren nachzuweisen, ist eine genaue Kenntnis des wirklichen Bestands und der tatsächlichen Schäden erforderlich, um diese mit den Messergebnissen zu vergleichen und deren Güte zu bewerten. Mit dem Abriss der Spandauer‐ Damm‐Brücke in Berlin ergab sich die Gelegenheit, zunächst eine großflächige Zustandsermittlung der Fahrbahnplatte bezüglich des Grads vorhandener Korrosionsschäden und des Verpresszustands von Spanngliedern vorzunehmen. Durch den vorgefundenen Zustand der Quervorspannung mit nachweislich vorhandenen Brüchen der Spanndrähte konnte an diesem Abrissbauwerk die Leistungsfähigkeit des Remanenzmagnetismusverfahrens zur Ortung von Spanndrahtbrüchen erstmals großflächig nachgewiesen werden, wobei auch der Vergleich der Untersuchungen mit und ohne Fahrbahnbelag durchgeführt wurde. Da der Anteil an vorhandenen Verpressfehlern nach großflächiger Auswertung sich als sehr gering herausstellte und an den ausgelösten Brückenteilen keine Verpressfehler vorhanden waren, wird in diesem Beitrag die Leistungsfähigkeit der Kombination von Radar und Ultraschall mit bildgebender Darstellung gezeigt. Damit wird es künftig möglich sein, Informationen zur Rekonstruktion nicht vorhandener Bestandspläne zu gewinnen.
Nachrichten: Beton‐ und Stahlbetonbau 12/2010
Authors: Stroetmann Richard , Hanek Dieter 
Published: December 2010

Abstract60 Jahre Krebs und KieferBDB‐Studentenförderpreis 20116. Hans Lorenz Symposium für Baugrunddynamik und SpezialtiefbauVBI: HOAI‐Novelle muss deutlich weiter reichenNeuauflage der VBI‐VOF‐Broschüre
Photonic immobilization of bsa for nanobiomedical applications: creation of high density microarrays and superparamagnetic bioconjugates
Authors: Parracino Antonietta , Gajula Gnana Prakash , di Gennaro Ane Kold , Correia Manuel , Neves‐Petersen Maria Teresa , Rafaelsen Jens , Petersen Steffen B. 
Published: December 2010

AbstractLight assisted molecular immobilization has been used for the first time to engineer covalent bioconjugates of superparamagnetic nanoparticles and proteins. The technology involves disulfide bridge disruption upon UV excitation of nearby aromatic residues. The close spatial proximity of aromatic residues and disulfide bridges is a conserved structural feature in proteins. The created thiol groups bind thiol reactive surfaces leading to oriented covalent protein immobilization. We have immobilized a model carrier protein, bovine serum albumin, onto Fe3O4@Au core–shell nanoparticles as well as arrayed it onto optically flat thiol reactive surfaces. This new immobilization technology allows for ultra high dense packing of different bio‐molecules on a surface, allowing the creation of multi‐potent functionalized active new biosensor materials, biomarkers identification and the development of nanoparticles based novel drug delivery system. Bioeng. 2011; 108:999–1010. © 2010 Wiley Periodicals, Inc.
High pressure gases: Role of dynamic intracellular pH in pasteurization
Authors: Giulitti Stefano , Cinquemani Claudio , Spilimbergo Sara 
Published: December 2010

AbstractCertain dense gases, including CO2 and N2O, are known to deactivate food pathogens safely. Complete deactivation requires disabling intracellular metabolic pathways by extracellular processing that causes membrane disruption, irreversible denaturation of proteins, or extraction of cell contents. At present, neither the precise physical and metabolic mechanisms nor their kinetics behind dense gas pasteurization are known. The mechanisms depend strongly on both the organism and the environment and may combine membrane disruption, membrane permeabilization, and altering pH. Herein we elucidate the mechanisms of dense gas inactivation with the aid of a novel approach for measuring intracellular pH (pHi) under high gas pressure. Using a pH‐sensitive GFP‐variant of S. cerevisiae as the probe, we demonstrate that membrane permeabilization by a non‐acidic gas, N2O, contributes to inactivation but at a rate that is relatively low compared to CO2. CO2 not only permeabilizes the membrane but also brings about a rapid drop in pHi, leading to greater deactivation. Mechanistic understanding is vital to develop safe and effective dense gas technologies for food treatment. Knowledge of pHi is also important in other cellular processes, including enzyme activity, gene transcription, and protein synthesis. The GFP technique has been demonstrated to be versatile even under pressure. Bioeng. 2011; 108:1211–1214. © 2010 Wiley Periodicals, Inc.
Modeling of shear stress experienced by endothelial cells cultured on microstructured polymer substrates in a parallel plate flow chamber
Authors: Brown Alan , Burke George , Meenan Brian J. 
Published: December 2010

AbstractThe application of physical stimuli to cell populations in tissue engineering and regenerative medicine may facilitate significant scientific and clinical advances. However, for the most part, these stimuli are evaluated in isolation, rather than in combination. This study was designed to combine two physical stimuli. The first being a microstructured tissue culture polystyrene substrate, known to produce changes in cell shape and orientation, and the second being laminar shear stress in a parallel plate flow chamber. The combined effects of these stimuli on endothelial cell monolayers cells were evaluated in a parallel plate flow chamber and using a computational fluid dynamics (CFD) model. The topography of the cell monolayers cultured on different microstructured surfaces was determined using confocal laser scanning microscopy (CLSM), and this topographic information was used to construct the CFD model. This research found that while the specific underlying structures were effectively planarized by the cell monolayer, significant differences in cell shape and orientation were observed on the different microstructured surfaces. Cells cultured on grooved substrates aligned in the direction of the grooves and showed higher retention after 1‐h LSS conditioning than those cultured on pillars. The modeled shear stress distributions also showed differences. While minor differences in the magnitude of shear stress were noted, aligned cell monolayers experienced significantly lower spatial gradients of shear stress when compared with cells that were not pre‐aligned by surface features. The results presented here provide an analysis of how one form of physical stimulus can be moderated by another and also provide a methodology by which the understanding of cell responses to topographic and mechanical stimuli can be further advanced. Bioeng. 2011; 108:1148–1158. © 2010 Wiley Periodicals, Inc.
Simple day-case surgery for pilonidal sinus disease
Authors: Thompson M R , Senapati A , Kitchen P 
Published: December 2010

Abstract

Background
Pilonidal disease is a common and usually minor disease. Although wide excisional surgery has been common practice, there are more simple alternatives. This review focused on the aetiology and management of pilonidal disease.

Methods
A comprehensive review of the literature on pilonidal disease was undertaken. MEDLINE searches for all articles listing pilonidal disease (1980–2010) were performed to determine the aetiology and results of surgical and non-surgical treatments. Single papers describing new techniques or minor modifications of established techniques were excluded. Further articles were traced through reference lists.

Results
Patients with minimal symptoms and those having drainage of a single acute abscess can be treated expectantly. Non-surgical treatments may be of value but their long-term results are unknown. There is no rational basis or need for wide excision of the abscess and sinus. Simple removal of midline skin pits, the primary cause of pilonidal disease, with lateral drainage of the abscess and sinus is effective in most instances. Hirsute patients with extensive primary disease and deep natal clefts, or with recurrent disease and unhealed midline wounds, may also require flattening of the natal cleft with off-midline skin closure. These more conservative procedures are usually done as a day case, require minimal care in the community and are associated with a rapid return to work. They also avoid the occasional debilitating complications of surgical treatment.

Conclusion
Simple day-case surgery to eradicate midline skin pits without wide excision of the abscesses and sinus is rational, safe and effective for patients with pilonidal sinus disease.
Modern chromatographic and electrophoretic measurements of antidepressants and their metabolites in biofluids
Authors: Plenis Alina , Bączek Tomasz 
Published: December 2010

AbstractDepression is one of the most frequently occurring psychiatric conditions affecting the economic and social functioning of people all over the world. There are a few classes of drugs commonly used to treat patients with depression disorders. Therapeutic drug monitoring of antidepressants provides the possibility to reduce side effects and optimize the treatment of patients with depression. Hence, there is a need to develop reliable analytical methods for the determination of these agents in biological fluids. Moreover, an important part of understanding the mechanisms of action of these medicines is also associated with the recognition of the metabolites' function because of their potential influence on therapeutic benefits and/or adverse effects. Some of them possess the same primary activity as their parent compounds and may contribute to the therapeutic efficacy whereas the biochemical actions of other metabolites may be different from that of the parent drug. In this review, several validated high‐performance liquid chromatographic, gas chromatographic and capillary electrophoretic methods for quantification of antidepressants and their metabolites in biofluids are compared. In addition, the review covers areas such as mechanism of actions, structure–activity relationships and metabolism of the cited antidepressants. Copyright © 2010 John Wiley & Sons, Ltd.
Aiding the understanding of novel freezing technology through numerical modelling with visual basic for applications (VBA)
Authors: Norton Tomas , Tiwari Brijesh 
Published: December 2010

AbstractThe rapid freezing of food is an important challenge faced by the frozen food industry, and investigations into more rapid and energy efficient ways of freezing foods are regularly carried out. Novel freezing technologies are not generally looked at by undergraduate engineers, as the techniques involved often require expensive or tightly regulated pilot equipment and may also involve complex underlying phenomena. However, computer‐aided studies can be used to put students in touch with the real engineering of novel freezing technology, and can add to their analysis and design skills by allowing them to study phenomena that may not have otherwise understood. In this paper, a one‐dimensional finite difference simulation procedure describing a novel freezing process, known as high‐pressure freezing, is presented. The freezing simulations are represented by an explicit enthalpy formulation, and agree well with experimental data. VBA was used during code development, and served as an attractive way to introduce engineering students to the analysis of novel freezing technology. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 530–538, 2013
Double Friedel–Crafts Acylation Reactions on the Same Ring of a Metallocene: Synthesis of a 2,5‐Diacetylphospharuthenocene
Authors: Carmichael Duncan , Le Floch Pascal , Le Goff Xavier F. , Piechaczyk Olivier , Seeboth Nicolas 
Published: December 2010

AbstractThe synthetic outcome of the Friedel–Crafts acylation of 1′,2′,3,3′,4,4′,5′‐heptamethylphospharuthenocene reflects the nature of the acylating agent, with alkanoyl anhydride/trifluoromethanesulfonic acid (TfOH) reagents giving monosubstitution at the phospholyl ring, whereas alkanoyl chloride/AlCl3 gives 2,5‐disubstitution. DFT calculations indicate that this unusual double acylation can be facilitated by the intervention of the phosphorus atom at an early stage in the reaction trajectory, with the acyl group being delivered from the phosphorus atom into the ring 2‐ or 2,5‐positions.
A Quantitative, Real‐Time Assessment of Binding of Peptides and Proteins to Gold Surfaces
Authors: Cohavi Ori , Reichmann Dana , Abramovich Renne , Tesler Alexander B. , Bellapadrona Giuliano , Kokh Daria B. , Wade Rebecca C. , Vaskevich Alexander , Rubinstein Israel , Schreiber Gideon 
Published: December 2010

AbstractInteractions of peptides and proteins with inorganic surfaces are important to both natural and artificial systems; however, a detailed understanding of such interactions is lacking. In this study, we applied new approaches to quantitatively measure the binding of amino acids and proteins to gold surfaces. Real‐time surface plasmon resonance (SPR) measurements showed that TEM1‐β‐lactamase inhibitor protein (BLIP) interacts only weakly with Au nanoparticles (NPs). However, fusion of three histidine residues to BLIP (3H‐BLIP) resulted in a significant increase in the binding to the Au NPs, which further increased when the histidine tail was extended to six histidines (6H‐BLIP). Further increasing the number of His residues had no effect on the binding. A parallel study using continuous (111)‐textured Au surfaces and single‐crystalline, (111)‐oriented, Au islands by ellipsometry, FTIR, and localized surface plasmon resonance (LSPR) spectroscopy further confirmed the results, validating the broad applicability of Au NPs as model surfaces. Evaluating the binding of all other natural amino acid homotripeptides fused to BLIP (except Cys and Pro) showed that aromatic and positively‐charged residues bind preferentially to Au with respect to small aliphatic and negatively charged residues, and that the rate of association is related to the potency of binding. The binding of all fusions was irreversible. These findings were substantiated by SPR measurements of synthesized, free, soluble tripeptides using Au‐NP‐modified SPR chips. Here, however, the binding was reversible allowing for determination of binding affinities that correlate with the binding potencies of the related BLIP fusions. Competition assays performed between 3H‐BLIP and the histidine tripeptide (3 His) suggest that Au binding residues promote the adsorption of proteins on the surface, and by this facilitate the irreversible interaction of the polypeptide chain with Au. The binding of amino acids to Au was simulated by using a continuum solvent model, showing agreement with the experimental values. These results, together with the observed binding potencies and kinetics of the BLIP fusions and free peptides, suggest a binding mechanism that is markedly different from biological protein–protein interactions.