bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth of Gold Bipyramids with Improved Yield and Their Curvature‐Directed Oxidation
Authors: Kou Xiaoshan , Ni Weihai , Tsung Chia‐Kuang , Chan Kong , Lin Hai‐Qing , Stucky Galen D. , Wang Jianfang 
Published: November 2007

AbstractThe surface‐plasmon properties of Au bipyramids are investigated using the finite‐difference time‐domain method. It is found that both the extinction cross sections and local electric‐field enhancements of Au bipyramids are larger than those of Au nanorods that have longitudinal surface plasmon (LSP) wavelengths close to those of Au bipyramids. Following this result the growth of Au bipyramids using cationic surfactants of variously sized headgroups as stabilizing agents is carried out. It is found that the growth using cetyltributylammonium bromide (CTBAB) produces Au bipyramids with tunable LSP wavelengths in high yields. The oxidation behaviour of Au bipyramids using hydrogen peroxide as the oxidizing agent is fully explored and the oxidation is found to occur preferentially at highly curved surface sites. It is further demonstrated that the oxidation rate can be controlled by varying the amounts of hydrogen peroxide and hydrochloric acid. This oxidation approach can be used in conjunction with the seed‐mediated growth in CTBAB solutions to produce Au bipyramids, the LSP wavelengths of which are finely tunable from 650 to 1300 nm.
Fast, frequency‐based, integrated register allocation and instruction scheduling
Authors: Cutcutache Ioana , Wong Weng‐Fai 
Published: November 2007

AbstractInstruction scheduling and register allocation are two of the most important optimization phases in modern compilers as they have a significant impact on the quality of the generated code. Unfortunately, the objectives of these two optimizations are in conflict with one another. The instruction scheduler attempts to exploit instruction‐level parallelism and requires many operands to be available in registers. On the other hand, the register allocator wants register pressure to be kept low so that the amount of spill code can be minimized. Currently these two phases are done separately, typically in three passes: prepass scheduling, register allocation and postpass scheduling. But this separation can lead to poor results. Previous works attempted to solve the phase‐ordering problem by combining the instruction scheduler with graph‐coloring‐based register allocators. The latter tend to be computationally expensive. Linear‐scan register allocators, on the other hand, are simple, fast and efficient. In this paper, we describe our effort to integrate instruction scheduling with a linear‐scan allocator. Furthermore, our integrated optimizer is able to take advantage of execution frequencies obtained through profiling. Our integrated register allocator and instruction scheduler achieved good code quality with significantly reduced compilation times. On the SPEC2000 benchmarks running on a 900 MHz ItaniumII, compared with OpenIMPACT, we halved the time spent in instruction scheduling and register allocation with negligible impact on execution times. Copyright © 2007 John Wiley & Sons, Ltd.
Verformungsbezogene mittragende Breite niedriger Verbundträger
Authors: Rieg Andreas , Kuhlmann Ulrike 
Published: November 2007

AbstractAufgrund der vergleichsweise großen Schlankheit niedriger Verbundträger wird bei diesen Trägern in sehr vielen Fällen die Einhaltung von Verformungsgrenzwerten querschnittsbestimmend. Das Verformungsverhalten dieser Träger wird dabei wesentlich durch die große Biegesteifigkeit des Betongurts und dessen Rissbildung bestimmt. Einer der maßgebenden Einflüsse auf die rechnerischen Verformungen ist die mittragende Breite des Betongurts.Neue Untersuchungen, die das Verformungsverhalten niedriger Verbundträger unter Berücksichtigung der Biegetragwirkung und Rissbildung des Betongurts betrachten, zeigen unter anderem, dass für die Spannungs‐ und die Verformungsberechnung unterschiedliche Werte der mittragenden Breite anzusetzen sind. Anhand umfangreicher experimenteller, analytischer und numerischer Untersuchungen konnten die Einflüsse auf die mittragende Breite analysiert werden. Auf Basis der Ergebnisse einer ausführlichen Parameterstudie wird ein Berechnungsansatz für die verformungsbezogene mittragende Breite entwickelt und ein Vorschlag zur quasi‐elastischen Verformungsberechnung niedriger Verbundträger gemacht. Es zeigt sich, dass die verformungsbezogene mittragende Breite im Besonderen von der Biegetragwirkung des Betongurts, dessen Rissbildung, dem Verhältnis von Gurtbreite zu Trägerlänge, der Steifigkeitsverteilung im Verbundträger und der Belastungshöhe abhängt.Mit dem entwickelten Berechungsansatz sind eine realistische Verformungsberechnung und eine wirtschaftliche Dimensionierung niedriger Verbundträger möglich.
Zur Verbundsicherung von kammerbetonierten Verbundträgern
Authors: Goralski Claus , Hegger Josef 
Published: November 2007

AbstractIn einem von der Deutschen Forschungsgemeinschaft geförderten Projekt [1] wurde das Trag‐ und Verformungsverhalten kammerbetonierter Verbundträger aus hochfestem Beton und hochfestem Stahl untersucht. Die rechnerische Erfassung des Kammerbetons erfordert die Beschreibung der Verbundmechanismen zwischen Kammerbeton und Stahlprofil. Hierzu wurde die Übertragung der Längsschubkraft zwischen Kammerbeton und Stahlprofil in Modell‐ und Biegeträgerversuchen unter positiver und negativer Momentenbeanspruchung untersucht. Durch die Entwicklung eines neuen Abscherversuchs konnte die Wirkungsweise von Kopfbolzendübeln sowohl bei druck‐ als auch bei zugbeanspruchtem Kammerbeton bestimmt werden. Die Verbundmechanismen am Biegeträger wurden anhand experimenteller Untersuchungen und dreidimensionaler nicht‐linearer Finite‐Elemente‐Modelle lokalisiert und quantifiziert.
Zur plastischen Bemessung hochfester kammerbetonierter Verbundträger
Authors: Hegger Josef , Goralski Claus 
Published: November 2007

AbstractDie traglaststeigernde Wirkung des Kammerbetons wurde bisher im Verbundträgerbau aufgrund fehlender mechanischer Modelle und Bemessungsregeln insbesondere bei hochfesten Baustoffen häufig nicht genutzt. Dieser Beitrag gibt einen Einblick in die Lastabtragungsmechanismen kammerbetonierter Verbundträger und beschreibt Bemessungsansätze zum wirtschaftlichen und sicheren Einsatz von hochfesten Baustoffen. Anhand einer Parameteruntersuchung zum Einfluss von hochfestem Kammerbeton und hochfestem Stahl auf die Querschnittstragfähigkeit des Verbundträgers wird ein plastisches Bemessungsverfahren für kammerbetonierte Verbundträger im positiven und negativen Momentenbereich hergeleitet. Die vorgestellten Ergebnisse sind Teil eines DFG‐Forschungsvorhabens, das in [1] und [2] ausführlich beschrieben ist.
Neue Untersuchungen zum Ermüdungsverhalten von Verbundträgern aus hochfesten Werkstoffen mit Kopfbolzendübeln und Puzzleleiste
Authors: Feldmann Markus , Hechler Oliver , Hegger Josef , Rauscher Sabine 
Published: November 2007

AbstractNeue Ergebnisse sind bei der Erforschung von Verbundträgern mit hochfestem Werkstoffen angefallen [1]. Unter anderem wurde das Ermüdungsverhalten verschiedener Verbundmittel (Kopfbolzendübel ∅︁ 22 mm und puzzleförmige Dübelleisten) bei Einsatz hochfester Werkstoffe (Stahl S 460 und Beton C 80/95) untersucht. Sowohl für die Kopfbolzendübel als auch für die Dübelleisten wurden zyklische Push‐Out‐Tests und Versuche an zyklisch belasteten Verbundträgern durchgeführt.Die Ergebnisse der zyklischen Push‐Out‐Tests mit Kopfbolzendübeln und hochfesten Werkstoffen deuten darauf hin, dass höhere Lastwechselzahlen ertragen werden können, ihre statische Resttragfähigkeiten waren nach ca. 1,0 Mio. Lastwechseln (ähnlich wie bei normalfesten Werkstoffen) um 25% reduziert. Bei den kontinuierlichen Verbundmitteln (Puzzleleiste) sind unter zyklischer Belastung zwar Anrisse aufgetreten, jedoch wurde hier keine Beeinträchtigung des Last‐Verformungsverhaltens oder der statischen Resttragfähigkeit festgestellt.Die zyklischen Trägerversuche mit Kopfbolzendübeln zeigen, dass die Vorhersage der Ermüdung mit den Regeln der aktuellen Normung – wie bei der Verwendung mit normalfesten Werkstoffen – nicht geeignet ist. Vielmehr gelingt eine gute Vorhersage des Risswachstums (und damit des Ermüdungsverhaltens) auf Grundlage der in [6] vorgestellten Verknüpfung des Dübelrisswachstums mit dem Schlupf in der Trägerverbundfuge. Für Verbundfugen mit Dübelleisten lässt sich über bruchmechanische Berechnungen ein theoretischer Grenzwert angeben, unterhalb dessen kein Risswachstum mehr auftritt. Allerdings hängt dies in Wirklichkeit stark von der gewählten Brennschnittqualität ab.
Mechanical and Structural Properties of Expanded Extrudates Produced from Blends of Native Starches and Natural Fibers of Henequen and Coconut
Authors: Aguilar‐Palazuelos E. , Zazueta‐Morales José de Jesús , Jiménez‐Arévalo Omar A. , Martínez‐Bustos Fernando 
Published: November 2007

AbstractThe aim of this research was to evaluate the effects of barrel temperature (130‐180ºC), feed moisture (14.6‐24.5%) and fiber content (0.0‐15.0%) on the physicochemical and structural properties of starch‐derived loose‐fill packaging materials (LFPM). Two blends were analyzed: one of corn starch and henequen fiber (Agave americana) (CS‐HF), and the other of potato starch and coconut fiber (PS‐CF). An experimental laboratory extruder with a 2.9 mm internal diameter die‐nozzle was used, and a hybrid central composite design was employed to study the LFPM, and the influence of some extrusion variables on mechanical properties, i.e. tensile strength (ϵ),stress (σ), flexion modulus (Ef), and structural properties; expansion index (EI), water absorption capacity (WAC), crystallinity by X‐ray diffraction, viscosity profiles and scanning electronic microscopy (SEM). In both extruded blends feed moisture was the most significant variable, increasing the values of EI and ϵ, and decreasing the values of σ and Ef when the feed moisture was decreased. The blend of PS‐CF had the highest values of EI, ϵ, σ and Ef,, and is the more appropriate for the preparation of LFPM. X‐ray diffraction analysis of the LFPM samples suggested the formation of almost completely amorphous structures, similar to those of commercial LFPM prepared from polystyrene. This research indicated that blends from natural sources like corn starch with henequen, and potato starch with coconut fibers have the potential to be used in the preparation of LFPM with similar characteristics to commercial LFPM, with the additional advantage of being biodegradable.
Visual Observation of Hydrolyzed Potato Starch Granules by α‐Amylase with Confocal Laser Scanning Microscopy
Authors: Apinan Soottitantawat , Yujiro Ikuta , Hidefumi Yoshii , Takeshi Furuta , Myllärinen Päivi , Forssell Pirkko , Poutanen Kaisa 
Published: November 2007

AbstractPorous starch was produced by digestion of freeze‐dried potato starch with α‐amylase from Bacillus sp. The surface structure of the granules became perforated and in the interior of the granules a capsule‐like cavity was formed, i.e. the hydrolyzed starch can be used as an encapsulant. The structure change of the granules was observed with confocal laser scanning microscopy and scanning electron microscopy. The degree of starch hydrolysis could be correlated with the Avrami equation. The activation energy of starch hydrolysis by α‐amylase was 83 kJ/mol.
Arguing to learn and learning to argue: Case studies of how students' argumentation relates to their scientific knowledge
Authors: von Aufschnaiter Claudia , Erduran Sibel , Osborne Jonathan , Simon Shirley 
Published: November 2007

AbstractIn this study we investigated junior high school students' processes of argumentation and cognitive development in science and socioscientific lessons. Detailed studies of the relationship between argumentation and the development of scientific knowledge are rare. Using video and audio documents of small group and classroom discussions, the quality and frequency of students' argumentation was analyzed using a schema based on the work of Toulmin (1958). In parallel, students' development and use of scientific knowledge was also investigated, drawing on a schema for determining the content and level of abstraction of students' meaning‐making. These two complementary analyses enabled an exploration of their impact on each other. The microanalysis of student discourse showed that: (a) when engaging in argumentation students draw on their prior experiences and knowledge; (b) such activity enables students to consolidate their existing knowledge and elaborate their science understanding at relatively high levels of abstraction. The results also suggest that students can acquire a higher quality of argumentation that consists of well‐grounded knowledge with a relatively low level of abstraction. The findings further suggest that the main indicator of whether or not a high quality of argument is likely to be attained is students' familiarity and understanding of the content of the task. The major implication of this work for developing argumentation in the classroom is the need to consider the nature and extent of students' content‐specific experiences and knowledge prior to asking them to engage in argumentation. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 45: 101–131, 2008
A virtual link routing scheme in the wireless home network architecture supporting end‐to‐end seamless connectivity
Authors: Kim Byounghoon , Park E. K. , Tak Sungwoo 
Published: November 2007

AbstractThis paper presents a communication framework for end‐to‐end seamless connectivity improvement in IEEE802.11‐based wireless home networks. The proposed communication framework incorporates the following two things: a new concept of wireless home network architecture and a new routing technique in an effort to improve wireless communication coverage and end‐to‐end seamless packet delivery respectively. First, the proposed wireless home network architecture based on the End‐to‐end Seamless multi‐hop COnnectivity based on Dual‐mode (ESCOD) integrates infrastructure and ad hoc modes in an IEEE 802.11‐based wireless home network. Second, the Virtual Link Routing (VLR) technique, a kind of ad hoc routing protocols working on the layer 2.5, provides mobile nodes with end‐to‐end seamless connectivity and packet delivery. We compare the performance of VLR with two prominent on‐demand routing protocols for Mobile Ad hoc Networks (MANET), Dynamic Source Routing (DSR) and Ad hoc On demand Distance Vector (AODV), in the ESCOD‐based wireless home network. Experiments show that our communication framework incorporating the VLR technique in the ESCOD‐based wireless home network architecture yields efficient performance in terms of the low failure rate of packet transmission, fast packet transmission time, network throughput, and a wider coverage area of wireless home networks. Copyright © 2007 John Wiley & Sons, Ltd.
In vivo x‐ray fluorescence measurements of lead, cadmium and mercury in occupational and environmental studies: a review of work conducted in Sweden 1970–2005
Authors: Börjesson Jimmy , Mattsson Sören 
Published: November 2007

AbstractLead, cadmium and mercury are toxic elements capable of causing temporary or permanent damage to human organs and tissues. An adequate control of these elements necessitates measurements in humans, on samples from man and the environment. This applies to both occupationally exposed subjects and to members of the general public including patients. The present paper will review the in vivo x‐ray fluorescence (XRF) technique for non‐invasive estimation of element levels directly in humans. Focus is on work conducted by researchers in Sweden between 1970 and 2005.Results from studies made with in vivo XRF on occupationally lead and cadmium exposed groups of workers have revealed very high levels of these elements in bone and kidneys, respectively. The development of the cadmium in vivo XRF technique implies usefilness even for measuring the low levels found in subjects of the general public, e.g. the detection limit for cadmium in kidney cortex allows for groups of smokers and non‐smokers to be separated. Retired lead workers show a clear association between bone lead and blood lead due to the endogenous lead excretion from bone. Longitudinal studies of retired workers show biological half‐lives for bone lead of several years. A study of mercury in vivo showed that the technique is capable of detecting the element in the kidneys of the most heavily exposed workers. In vivo XRF in oncology and rheumatology subjects, administered with therapeutic compounds containing platinum and gold, respectively, helps to understand the retention of these compounds in the human body. Copyright © 2007 John Wiley & Sons, Ltd.
Spectrometry methods for in vivo bone strontium measurements
Authors: Zamburlini M. , Pejović‐Milić A. , Chettle D. R. 
Published: November 2007

AbstractIn vivo x‐ray fluorescence (XRF) and dual‐photon absorptiometry (DPA) are two widely accepted radiation‐based measurement techniques. The first one is mainly used for the measurement of toxic elements in the human body, while the second one is clinically used to measure bone density. In this paper we present a literature review of the application of these two techniques to in vivo strontium measurements. Strontium is a natural constituent of the human skeleton, where it may exert beneficial or detrimental effects depending on the dietary intake and other factors. Recently, several medical publications have focused on the beneficial effects on bone of pharmacological dosages of strontium, especially with regard to its anti‐osteoporotic effects. However, the mechanism by which strontium exerts its therapeutic action is still not known. XRF and DPA have the potential of providing unique information on bone strontium concentration, retention and elimination that cannot be gained at the moment in any other way. Copyright © 2007 John Wiley & Sons, Ltd.
Muscle wasting in chronic kidney disease: the role of the ubiquitin proteasome system and its clinical impact
Authors: Rajan Vik R. , Mitch William E. 
Published: November 2007

AbstractMuscle wasting in chronic kidney disease (CKD) and other catabolic diseases (e.g. sepsis, diabetes, cancer) can occur despite adequate nutritional intake. It is now known that complications of these various disorders, including acidosis, insulin resistance, inflammation, and increased glucocorticoid and angiotensin II production, all activate the ubiquitin–proteasome system (UPS) to degrade muscle proteins. The initial step in this process is activation of caspase-3 to cleave the myofibril into its components (actin, myosin, troponin, and tropomyosin). Caspase-3 is required because the UPS minimally degrades the myofibril but rapidly degrades its component proteins. Caspase-3 activity is easily detected because it leaves a characteristic 14kD actin fragment in muscle samples. Preliminary evidence from several experimental models of catabolic diseases, as well as from studies in patients, indicates that this fragment could be a useful biomarker because it correlates well with the degree of muscle degradation in dialysis patients and in other catabolic conditions.
Total Hip Arthroplasty is Less Painful at 12 Months Compared with Hemiarthroplasty in Treatment of Displaced Femoral Neck Fracture
Authors: Macaulay William , Nellans Kate W. , Iorio Richard , Garvin Kevin L. , Healy William L. , Rosenwasser Melvin P. 
Published: November 2007

Objectives The Displaced Femoral (neck fracture) Arthroplasty Consortium for Treatment and Outcomes (DFACTO) study compared total hip arthroplasty (THA) to hemiarthroplasty in the treatment of displaced femoral neck fractures. Design This study was designed as a prospective, randomized clinical trial. Setting The study was conducted in five US academic and private medical centers. Patients Patients were composed of independent, mentally competent individuals, >50 years old who suffered a displaced femoral neck fracture without existing arthritis at the hip. Forty-one patients were enrolled. Main outcome measures Functional outcomes and quality of life were assessed at 6 and 12 months post-fracture using the SF-36, Western Ontario and McMaster University Osteoarthritis Index (WOMAC), the Harris Hip Score, and the Timed “Up & Go” Test (TUG test). Results Groups were equivalent at baseline in terms of age, comorbid conditions, and functional status. At 6 months, there were no significant differences between the groups using the outcome measures or overall rates of complications. There was one dislocation in the THA group (5.8% of patients). At 12 months, the THA group reported significantly less pain (53.2 ± 10.2) than the hemiarthroplasty group (42.4 ± 11.5) using the SF-36 ( p = 0.02). Using the TUG Test, we observed a greater proportion of THA patients remain functionally independent 1 year after surgery compared the hemiarthroplasty group ( p = 0.08, controlling for age and sex). Conclusions These differences in pain and functional outcomes suggest THA is a viable treatment option for the active elderly displaced femoral neck fracture population.
Voltage‐dependent potassium channels are involved in staurosporine‐induced apoptosis of rat mesenchymal stem cells
Authors: Wang Shaoping , Wang Jian‐an , Li Jun , Zhou Jinghong , Wang Hai 
Published: November 2007

AbstractThe strategy of mesenchymal stem cells (MSCs) transplantation is limited by the inability to deliver a large number of grafted cells that resist peri‐transplantation apoptosis in ischemic tissues, and this led us to investigate methods of improving the viability of these cells. We demonstrate the presence of voltage‐gated potassium channels in rat MSCs that can be activated by staurosporine (ST). MSCs exposed to ST underwent apoptotic cell changes. Tetraethylammonium (TEA), a classic blocker of K+ channels, blocked the ST‐induced augmentation of K+ currents, and reduced ST‐induced apoptosis. Furthermore, we found that TEA prevented the ST‐induced increase in expression of the pro‐apoptotic protein Bax and decrease of the anti‐apoptotic protein Bcl‐2. Taken together, our findings suggest that voltage‐gated potassium is involved in ST‐induced apoptosis of rat MSCs. TEA blocks the ST‐induced augmentation of K+ currents, alters the expression of Bcl‐2 family proteins induced by ST, and attenuates the apoptosis of rat MSCs.
Aqueous extract of the Chinese medicine, Danggui‐Shaoyao‐San, inhibits apoptosis in hydrogen peroxide‐induced PC12 cells by preventing cytochrome c release and inactivating of caspase cascade
Authors: Qian Yun‐fei , Wang Hua , Yao Wen‐bing , Gao Xiang‐dong 
Published: November 2007

AbstractDanggui‐Shaoyao‐San (DSS), a traditional Chinese medicine used for centuries for the enhancement of women's health, has been shown to display therapeutic efficacy on senile dementia. In the present study, using a rat pheochromocytoma (PC12) cell line, the effect of DSS on hydrogen peroxide (H2O2) induced apoptosis was studied. The apoptosis in H2O2‐induced PC12 cells was accompanied by downregulation of Bcl‐2, upregulation of Bax, the release of mitochondrial cytochrome c into cytosol, and sequential activation of caspase‐9 and −3. DSS was able to suppress all these changes and eventually protected against H2O2‐induced apoptosis. Taken together, these results suggest that treatment of PC12 cells with DSS can block H2O2‐induced apoptosis by the regulation of Bcl‐2 family members, as well as suppression of cytochrome c release and caspase cascade activation.