bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early days of protein hydrogen exchange: 1954–1972
Authors: Baldwin Robert L. 
Published: March 2011

AbstractHydrogen exchange (HX) is recognized today as one of the most powerful and versatile tools available to protein scientists, especially for studying protein conformational change. This short history traces the beginnings of the HX method and the basic problems that faced the founders. Protein HX began as a simple idea with a straightforward goal, but the first experiments revealed both the unexpected complexity of the subject and the potential power of the method for probing deep into how proteins work. By 1972, the chemistry of the exchange reaction in peptides began to be well understood, but the challenge of getting and interpreting data on HX for individual peptide NH protons in proteins remained for decades longer. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Structural characterization of the mitomycin 7‐O‐methyltransferase
Authors: Singh Shanteri , Chang Aram , Goff Randal D. , Bingman Craig A. , Grüschow Sabine , Sherman David H. , Phillips George N. , Thorson Jon S. 
Published: March 2011

AbstractMitomycins are quinone‐containing antibiotics, widely used as antitumor drugs in chemotherapy. Mitomycin‐7‐O‐methyltransferase (MmcR), a key tailoring enzyme involved in the biosynthesis of mitomycin in Streptomyces lavendulae, catalyzes the 7‐O‐methylation of both C9β‐ and C9α‐configured 7‐hydroxymitomycins. We have determined the crystal structures of the MmcR–S‐adenosylhomocysteine (SAH) binary complex and MmcR–SAH–mitomycin A (MMA) ternary complex at resolutions of 1.9and 2.3 Å, respectively. The study revealed MmcR to adopt a common S‐adenosyl‐L‐methionine‐dependent O‐methyltransferase fold and the presence of a structurally conserved active site general acid–base pair is consistent with a proton‐assisted methyltransfer common to most methyltransferases. Given the importance of C7 alkylation to modulate mitomycin redox potential, this study may also present a template toward the future engineering of catalysts to generate uniquely bioactive mitomycins. Proteins 2011. © 2011 Wiley‐Liss, Inc.
Toward the quantum chemical calculation of nuclear magnetic resonance chemical shifts of proteins
Authors: Frank Andrea , Onila Ionut , Möller Heiko M. , Exner Thomas E. 
Published: March 2011

AbstractDespite the many protein structures solved successfully by nuclear magnetic resonance (NMR) spectroscopy, quality control of NMR structures is still by far not as well established and standardized as in crystallography. Therefore, there is still the need for new, independent, and unbiased evaluation tools to identify problematic parts and in the best case also to give guidelines that how to fix them. We present here, quantum chemical calculations of NMR chemical shifts for many proteins based on our fragment‐based quantum chemical method: the adjustable density matrix assembler (ADMA). These results show that 13C chemical shifts of reasonable accuracy can be obtained that can already provide a powerful measure for the structure validation. 1H and even more 15N chemical shifts deviate more strongly from experiment due to the insufficient treatment of solvent effects and conformational averaging. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Cell selectivity and interaction with model membranes of Val/Arg‐rich peptides
Authors: Ma Qing‐Quan , Shan An‐Shan , Dong Na , Gu Yao , Sun Wen‐Yu , Hu Wan‐Ning , Feng Xing‐Jun 
Published: March 2011

AbstractAntimicrobial peptides are major components of the innate self‐defence system and a large number of peptides have been designed to study the mechanism of action. In the present study, a small combinatorial library was designed to study whether the biological activity of Val/Arg‐rich peptides is associated with targeted cell membranes. The peptides were produced by segregating hydrophilic residues on the polar side and hydrophobic residues on the opposite side. The peptides displayed strong antimicrobial activity against Gram‐negative and Gram‐positive bacteria, but weak haemolysis even at a concentration of 256 µM. CD spectra showed that the peptides formed α‐helical‐rich structure in the presence of negatively charged membranes. The tryptophan fluorescence and quenching experiments indicated that the peptides bound preferentially to negatively charged phospholipids over zwitterionic phospholipids, which corresponds well with the biological activity data. In the in vivo experiment, the peptide G6 decreased the bacterial counts in the mouse peritoneum and increased survival after 7 days. Overall, a high binding affinity with negatively charged phospholipids correlated closely with the cell selectivity of the peptides and some peptides in this study may be likely candidates for the development of antibacterial agents. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.
Signal readout for pyroelectric detector based on relaxor ferroelectric single crystals
Authors: Wang Jiang , Jing Yiou , Jing Weiping , Li Yan Jin 
Published: March 2011

AbstractRelaxor‐based ferroelectric single crystals, such as (1 − x)Pb(Mg1/3Nb2/3)O3xPbTiO3 (PMNxPT, or PMNT) single crystals, exhibit large pyroelectric response, low thermal diffusivity, and high temperature stability. To fabricate high performance infrared detectors with relaxor‐based single crystals, the related readout circuit was investigated to increase signal‐to‐noise ratio, and 8 × 1 CMOS readout circuit is fabricated to gain very weak current, which provides a solution for uncooled large focal plane arrays devices based on relaxor‐based single crystals.
A compact quantum statistical model for the ballistic nanoscale MOSFETs
Authors: Varpula A. , Lebedeva N. , Kuivalainen P. 
Published: March 2011

AbstractWe develop an analytical quantum statistical model for nanoscale metal‐oxide‐semiconductor field‐effect transistors (MOSFETs). The model describes transport both in the scattering‐limited and ballistic regimes. The expression for the channel current is derived with the Keldysh nonequilibrium Green's function technique. The obtained quantum statistical current expression reduces to the semiclassical one in the absence of scattering. The model indicates that in nanoscale devices the scattering processes become dependent on the bias voltages. The calculated results for the I–V characteristics are in good agreement with the experimental results in the case of a 70 nm MOSFET. The model includes a minimal number of fitting parameters and it can be used in the design of ultra large‐scale integrated circuits.
Raman studies of hexagonal MoO3 at high pressure
Authors: Zhang C. C. , Zheng L. , Zhang Z. M. , Dai R. C. , Wang Z. P. , Zhang J. W. , Ding Z. J. 
Published: March 2011

AbstractThe transition‐metal oxide MoO3 is an important semiconductor and has various technological applications in catalysts, electrochromic and photochromic devices, gas sensors, and battery electrodes. In this study, the hexagonal MoO3 prepared by a hydrothermal method is in morphology of microrod with diameter of 0.8–1.2 µm and length of 2.0–4.3 µm. Its structural stability was investigated by an in situ Raman scattering method in a diamond anvil cell up to 28.7 GPa at room temperature. The new Raman peak around 1000 cm−1 implies that a phase transition from hexagonal to amorphous starts at 5.6 GPa, and the evolution of the Raman spectra indicates that the structural transition is completed at about 13.2 GPa. After releasing pressure to ambient condition, the Raman spectrum pattern of the high pressure phase was retained, revealing that the phase transition is irreversible.
Interfacial reactions of nickel ion containing multilayers and nickel ultra‐thin films with an interpenetrating polymer network substrate
Authors: Tang Dongyan , Han Shuai , Li Ji 
Published: March 2011

AbstractAn interpenetrating polymer network (IPN) substrate was prepared by dip‐pulling a silicon wafer or glass plate into polymer precursors, followed by solidification at room temperature. The nickel ion containing Langmuir–Blodgett (LB) multilayers was subsequently fabricated onto the IPN substrate by a LB technique, and then the nickel ultra‐thin films were deposited by chemical reduction. The interfacial reactions, the metal transformations and the non‐metal bond types during the film formation were detected by the X‐ray photoelectron spectroscopy, atomic force microscope and attenuated total reflection infrared spectroscopy. Copyright © 2011 John Wiley & Sons, Ltd.
Flexible modeling of the effects of continuous prognostic factors in relative survival
Authors: Mahboubi Amel , Abrahamowicz Michal , Giorgi Roch , Binquet Christine , Bonithon‐Kopp Claire , Quantin Catherine 
Published: March 2011

AbstractRelative survival methods permit separating the effects of prognostic factors on disease‐related ‘excess mortality’ from their effects on other‐causes ‘natural mortality’, even when individual causes of death are unknown. As in conventional ‘crude’ survival, accurate assessment of prognostic factors requires testing and possibly modeling of non‐proportional effects and, for continuous covariates, of non‐linear relationships with the hazard. We propose a flexible extension of the additive‐hazards relative survival model, in which the observed all‐causes mortality hazard is represented by a sum of disease‐related ‘excess’ and natural mortality hazards. In our flexible model, the three functions representing (i) the baseline hazard for ‘excess’ mortality, (ii) the time‐dependent effects, and (iii) for continuous covariates, non‐linear effects, on the logarithm of this hazard, are all modeled by low‐dimension cubic regression splines. Non‐parametric likelihood ratio tests are proposed to test the time‐dependent and non‐linear effects. The accuracy of the estimated functions is evaluated in multivariable simulations. To illustrate the new insights offered by the proposed model, we apply it to re‐assess the effects of patient age and of secular trends on disease‐related mortality in colon cancer. Copyright © 2011 John Wiley & Sons, Ltd.
The inclusion of historical control data may reduce the power of a confirmatory study
Authors: Cuffe Robert L. 
Published: March 2011

AbstractLarge sample sizes in clinical trials increase the cost of clinical research and delay the availability of new treatments. Fewer patients could be recruited into clinical trials if historical data on the comparator could be used reliably in a trial's analysis. However, old trials may bias rather than augment data from a new trial if, for example, the standard of care has improved over time. A hierarchical model for the data from the current and historical trials decreases the weight given to the historical data in line with the discrepancy between the results from the different trials. This reduces the risk of substantial bias. This paper shows that this down‐weighting is not sufficiently sensitive to differences in the response rates between trials. Motivated by recent trials in HIV, this paper proposes and examines a more conservative weighting of historical data. Simulation showed that both the standard hierarchical and the proposed weighting of historical data led to Type II error rates worse than those attained by ignoring the historical data completely. This underlines the risks of including historical data in the primary analysis of a trial for which strict control of error rates is paramount. Copyright © 2011 John Wiley & Sons, Ltd.
Estimating standard errors for life expectancies based on complex survey data with mortality follow‐up: A case study using the National Health Interview Survey Linked Mortality Files
Authors: Schenker Nathaniel , Parsons Van L. , Lochner Kimberly A. , Wheatcroft Gloria , Pamuk Elsie R. 
Published: March 2011

AbstractLife expectancy is an important measure for health research and policymaking. Linking individual survey records to mortality data can overcome limitations in vital statistics data used to examine differential mortality by permitting the construction of death rates based on information collected from respondents at the time of interview and facilitating estimation of life expectancies for subgroups of interest. However, use of complex survey data linked to mortality data can complicate the estimation of standard errors. This paper presents a case study of approaches to variance estimation for life expectancies based on life tables, using the National Health Interview Survey Linked Mortality Files. The approaches considered include application of Chiang's traditional method, which is straightforward but does not account for the complex design features of the data; balanced repeated replication (BRR), which is more complicated but accounts more fully for the design features; and compromise, ‘hybrid’ approaches, which can be less difficult to implement than BRR but still account partially for the design features. Two tentative conclusions are drawn. First, it is important to account for the effects of the complex sample design, at least within life‐table age intervals. Second, accounting for the effects within age intervals but not across age intervals, as is done by the hybrid methods, can yield reasonably accurate estimates of standard errors, especially for subgroups of interest with more homogeneous characteristics among their members. Published in 2011 by John Wiley & Sons, Ltd.
Entwerfen von leichten Dachtragwerken aus Glas und Stahl
Authors: Kloft Harald , Fäth Klaus , Wilhelm Viktor 
Published: March 2011

AbstractDie Leichtigkeit von Dachtragwerken wird nicht durch Minimierung der Masse erzielt. Auch die Verwendung der Werkstoffe Glas und Stahl ist per se noch kein Garant für die filigrane Erscheinung einer Konstruktion. Der Entwurf von leichten Dachtragwerken aus Glas und Stahl gestaltet sich vielmehr als Optimierungsaufgabe von intelligenter Verteilung der Masse und gezielter Nutzung der Leistungsfähigkeit der beiden Werkstoffe. Wesentlicher Aspekt ist die Abstimmung des Tragwerksentwurfes auf die architektonische Entwurfsidee und die örtlichen Randbedingungen. Dies erfordert von Beginn an eine enge Zusammenarbeit von Architekt und Ingenieur.In dem Beitrag werden die Entwurfsprozesse von drei leichten Dachtragwerken aus Stahl und Glas vorgestellt und die Rolle des entwerfenden Ingenieurs diskutiert. Die Tragwerke wurden von Klaus Fäth und Harald Kloft, als Inhaber des Ingenieurbüros osd – office for structural design, Frankfurt/M., in Zusammenarbeit mit Viktor Wilhelm, Stuttgart, geplant.Designing lightweight roof structures of glass and steel. Lightness of roof structures does not mean to minimize the building mass. As well, the use of glass and steel will not guarantee a sophisticated appearance of a construction. Designing a lightweight, transparent structure is much more a task of optimization by intelligent arrangement of the building mass and by the defined use of the materials glass and steel. An essential aspect is the structural design in relation to the architectural idea and the urban context. All together, this needs a close cooperation of architect and engineer from the very beginning of a design process.In the following three lightweight roof structures are presented and the role of the engineers will be discussed. All projects are designed by Klaus Fäth and Harald Kloft, the principals of the Frankfurt based engineering practice osd – office for structural design in close cooperation with Viktor Wilhelm from Stuttgart.
Einsatz von tragenden Glaselementen in Glasbrücken und Glaspavillions
Authors: Wellershoff Frank , Sendelbach Michael , Schmitt Felix 
Published: March 2011

AbstractMit der zunehmenden Erforschung und Akzeptanz von Glaselementen im konstruktiven Ingenieurbau werden reale Anwendungen mit vertretbarem Prüf‐ und Genehmigungsaufwand umsetzbar. Das Stabilitätsverhalten von Glaselementen aus Mehrfachverbundglas ist in den letzten Jahren umfangreich erforscht worden, so dass Glasstützen und Glasträger mit den vorgeschlagenen Stabilitätsnachweisen und ergänzenden FE‐Analysen gut dimensioniert werden können. Die Planung, Bauteilprüfung und Montage aktueller Glasbrücken und Glaspavillions für die permanente öffentliche Nutzung wird vorgestellt. Neben den projektbezogenen Stabilitätsprüfungen der Glasbauteile wird besonders auf die Anschlüsse sowie auf die Montage der Elemente eingegangen. Glasbrücken wurden in 2010 errichtet im “Eaton Center” in Calgary und im “Ritz‐Carlton Hotel” in Toronto. Glasstützen und deren Anschlüsse wurden entworfen und getestet für den U‐Bahn Eingang “Willy‐Brandt‐Platz” in Frankfurt und für den Glaspavillion im “Kravis Center” in Los Angeles.Use of structural glass elements in glass bridges and glass pavilions. The use of structural glass elements becomes more and more accepted due to the increasing knowledge based on recent research projects. Real applications are meanwhile possible with realistic time and cost efforts for the approval by the building authorities. The stability of multi‐laminated glass elements has been intensively investigated in the recent years. Glass columns and glass beams can meanwhile be dimensioned based on the related publications and additional FE‐analysis. The design and the erections of current glass bridges and glass pavilions for the public use are described. Project specific stability tests and detailed connection tests are shown. Glass bridges have been erected in 2010 in the “Eaton Centre” in Calgary and in the “Ritz‐Carlton Hotel” in Toronto. Glass columns and their connections have been designed and tested for the Subway station “Willy Brandt Platz” in Frankfurt and the glass pavilion in the “Kravis Center” in Los Angeles.
Leicht und transparent – eine Glasbrücke in Lissabon
Authors: Keil Andreas , Straub Klaus 
Published: March 2011

AbstractDas “Centre of the Unknown”, eine erst kürzlich fertiggestellte biomedizinische Forschungseinrichtung der Champalimaud‐Stiftung in Lissabon, Portugal, wurde von den Architekten Charles Correa Associates aus Mumbai, Indien, entworfen. Es besteht aus zwei Gebäudekomplexen, in denen die Forschungslabors, ein Auditorium und Ausstellungsbereich sowie die Büros der Stiftung Platz finden. Das “Centre of the Unknown” befindet sich im Stadtteil Belém, hier mündet der Fluss Tejo in den Atlantischen Ozean. Diese Lage ist von besonderer historischer Bedeutung, denn von hier aus setzten die portugiesischen Pioniere im 15. und 16. Jahrhundert die Segel, um das “Unbekannte” zu entdecken.Ein optisches Highlight ist die leichte, 21 m lange Glasbrücke mit einer Hülle aus gebogenen Scheiben, die die beiden Gebäudekomplexe miteinander verbindet. Eine filigrane unterspannte Stahlkonstruktion bildet zugleich die Unterkonstruktion für die äußere Glashülle. Auch die Gehfläche und die Brüstungen bestehen aus Glaselementen und verleihen der Gesamtkonstruktion das geforderte Maß an Eleganz und Transparenz. Der Aufsatz geht auf die unterschiedlichen Anforderungen dieser ungewöhnlichen Brücke ein und zeichnet dabei den Entwurfsprozess bis hin zur Fertigstellung nach (Bild 1).Light‐weight and transparent – a glass bridge in Lisbon. The “Centre of the Unknown”, a recently completed biomedical research facility of the Champalimaud Foundation in Lisbon, Portugal, was designed by Charles Correa Associates from Mumbai, India. It comprises two building complexes set in a large public area that accommodate treatment units, research laboratories, an auditorium and exhibition area, as well as the offices of the Champalimaud Foundation itself. The ‘Champalimaud Centre for the Unknown’ is located in the Belém district of Lisbon, where the Tagus River flows into the Atlantic Ocean. Its location is of particular historical significance, as it is the place from where Portuguese pioneers set sail to discover the ‘unknown’ in the 15th and 16th centuries.A visual highlight is the light‐weight steel and glass bridge that connects the two buildings. The glass envelope encasing the bridge consists of curved panels of laminated glass. A filigree cable supported steel structure also forms the substructure of the glass envelope. The walkway and the railing also consist of laminated safety glass and thereby confer upon the entire structure the desired sense of elegance and transparency. The technical report addresses the various requirements of this out of the ordinary bridge and outlines the bridge design from conceptual design to completion (Fig. 1).
Verwendung von Glas zur Aussteifung von Gebäuden
Authors: Freitag Claudia , Wörner Johann‐Dietrich 
Published: March 2011

AbstractDer Trend in der modernen Architektur zu Stahl‐Glas‐Gebäuden entspricht dem allgemeinen Zeitgeist nach Klarheit und Funktionalität einer Gebäudestruktur. Dies weckt den Wunsch, Glasscheiben neben der bisherigen Einhausungsfunktion auch zur Tragfähigkeit, insbesondere zur Schubaussteifung der Gebäude heranzuziehen, um somit auf Aussteifungsverbände verzichten zu können.In vorliegender Studie soll dies über Lagermechanismen erfolgen, die eine definierte Vorspannung ermöglichen, wodurch bis zu einem gewissen Grad Zugspannungen in der Scheibe durch den vorhandenen Druck‐Vorspannungszustand aufgenommen werden können.Es werden zwei Systeme mit mechanisch aufgebrachter Vorspannung betrachtet, ein System mit diskreter Ausklotzung in den Ecken, ein System mit kontinuierlicher Linienlagerung.Utilisation of glass panes as structural bracings. The trend in modern architecture to steel and glass buildings corresponds to the general spirit of the time for clarity and functionality of a building structure. Thereof arouses the inspiration to utilise windowpanes in addition to their common function as façade material for structural bracing by application of a defined compression pre‐stress state in the window plane, which provides for taking over shear load contingent tensile stresses to a certain degree.The present study observes two bearing systems for mechanical application of before‐mentioned compression pre‐stress state; one system with discrete block clamping in the window corners, and one system with continuous line bearing.
Relationship between characteristic parameters of impact test for safety glasses
Authors: Pacios Álvarez Antonia , Postigo Pozo Sergio , Huerta Gómez de Merodio Maria Consuelo 
Published: March 2011

AbstractThis paper presents results from experiments on soft impact testing of glass plates. In the experiments, a 50‐kg twin‐tire pendulum was used to strike different glass plates at speeds of up to 4.85 m/s. The impact parameters that were defined and measured include the micro‐strain in the glass plates, pendulum acceleration, duration of contact, pendulum height, and maximum tire track values. A total of 240 impacts on 17 specimens were carried out for different glass thicknesses (5, 6, 8, and 10 mm) and boundary conditions (four sides, two sides and four pin points supported). Tempered monolithic and toughened bi‐layered laminated plates were tested. To find out if the selected parameters represent the phenomena, multiple regression analysis was carried out.Abhängigkeit der charakteristischen Kenngrößen bei Stoßbelastung an VSG. Dieser Beitrag zeigt Ergebnisse von experimentellen Untersuchungen des weichen Stoßes auf Glasplatten. In diesen Versuchen wurde ein 50‐kg‐Doppelreifenpendel genutzt, um verschiedene Glasplatten mit Geschwindigkeiten des Pendels bis zu 4,85 m/s zu pendeln. Die definierten und gemessenen Eigenschaften des Stoßes beinhalteten die Dehnungen in der Scheibe, die Pendelbeschleunigung, die Dauer des Pendelkontakts, die Fallhöhe und die maximale Kontaktfläche. Eine Gesamtzahl von 240 Pendelschlagversuchen an 17 Probekörpern wurde für verschiedene Glasdicken (5, 6, 8 und 10 mm) und Randbedingungen (allseitig und zweiseitig sowie vierfach punktförmig gelagert) durchgeführt. Thermisch vorgespanntes, monolithisches und vorgespanntes Zweifach‐Verbundglas wurden untersucht. Zur Ermittlung, ob die ausgewählten Parameter die Realität korrekt wiedergeben, wurde eine multiple Regressionsanalyse durchgeführt.