bluuebunny/crossref_metadata_2025_split huggingface dataset:
„Zwerge“ aus dem Minilabor
Authors: Marmé Nicole , Aupperle‐Pauls Annegret , Pauls Frederik , Knemeyer Jens‐Peter 
Published: October 2014

AbstractDie Nanotechnologie in all ihren Facetten wird für die moderne Gesellschaft immer wichtiger und gilt als eine der Schlüsseltechnologien des 21. Jahrhunderts. In diesem Artikel werden schulgerechte Synthesen von Gold‐ und Silber‐Nanopartikeln mit Hilfe eines Minilabors vorgestellt, die im außerschulischen Lernort, im Schülerpraktikum oder auch im Rahmen größerer Projekte eigenständig durchgeführt werden können. Außerdem wird ein schülerzentriertes Konzept für eine Nanotechnologie‐Unterrichtseinheit vorgestellt, welches auf den Erwerb von den in den Bildungsplänen geforderten Schlüsselkompetenzen zielt und den Schülerinnen und Schülern einen Einblick in den Wissenschaftsalltag und in wissenschaftliche Arbeits‐ und Vorgehensweisen geben soll.
Estimation of expectedness: Predictive accuracy of standard therapy outcomes in randomized phase 3 studies in epithelial ovarian cancer
Authors: Castonguay Vincent , Wilson Michelle K. , Diaz‐Padilla Ivan , Wang Lisa , Oza Amit M. 
Published: October 2014

BACKGROUNDThe anticipated clinical outcome of the standard/control arm is an important parameter in the design of randomized phase 3 (RP3) trials to properly calculate sample size, power, and study duration. Changing patterns of care or variation in the study population enrolled may lead to a deviation from the initially anticipated outcome. The authors hypothesized that recent changes in patterns of care in epithelial ovarian cancer (EOC) have led to challenges in correctly estimating the outcome of control groups.METHODSA systematic review of the literature was conducted for RP3 trials of EOC published between January 2000 and December 2010. The expected outcome of the control arm as well as the actual outcome achieved by this cohort was collected and a ratio (actual‐over‐expected ratio) was calculated. The estimation of outcome was deemed accurate if the outcome of the control arm was between 0.75 to 1.25 times the anticipated outcome.RESULTSA total of 35 trials were eligible for analysis. Fifteen trials had survival as the primary endpoint whereas 20 had a progression‐based primary endpoint. In total, 12 of 15 trials with a survival‐based endpoint significantly underestimated the outcome of the control arm, whereas only 4 of 20 trials with a progression‐based endpoint did. Studies with a survival endpoint underestimated outcome more frequently than those with a progression endpoint (P<.001).CONCLUSIONSSurvival of the control arm has frequently been underestimated in recent EOC RP3 trials. This underestimation means that the initial statistical assumptions of these trials may have been inaccurate. Underestimating the outcome of the control arm may result in trials being underpowered to demonstrate the absolute benefit they were designed to show. Cancer 2015;121:413–422. © 2014 American Cancer Society.
Modification of D–A–π–A Configuration toward a High‐Performance Triphenylamine‐Based Sensitizer for Dye‐Sensitized Solar Cells: A Theoretical Investigation
Authors: Tarsang Ruangchai , Promarak Vinich , Sudyoadsuk Taweesak , Namuangruk Supawadee , Kungwan Nawee , Jungsuttiwong Siriporn 
Published: October 2014

AbstractIn an attempt to shed light on how the addition of a benzothiadiazole (BTD) moiety influences the properties of dyes, a series of newly designed triphenylamine‐based sensitizers incorporating a BTD unit as an additional electron‐withdrawing group in a specific donor–acceptor–π‐acceptor architecture has been investigated. We found that different positions of the BTD unit provided significantly different responses for light absorption. Among these, it was established that the further the BTD unit is away from the donor part, the broader the absorption spectra, which is an observation that can be applied to improve light‐harvesting ability. However, when the BTD unit is connected to the anchoring group a faster, unfavorable charge recombination takes place; therefore, a thiophene unit was inserted between these two acceptors, providing redshifted absorption spectra as well as blocking unfavorable charge recombination. The results of our calculations provide valuable information and illustrate the potential benefits of using computation‐aided sensitizer design prior to further experimental synthesis.
Photoresponsive Stripe Pattern in Achiral Azobenzene Liquid Crystals
Authors: Okano Kunihiko , Aya Satoshi , Araoka Fumito , Obara Haruki , Sato Shiori , Yamashita Takashi , Takezoe Hideo , Asakura Kouichi 
Published: October 2014

AbstractA periodic stripe pattern is found in the nematic phase close to the smectic phase of photoresponsive achiral liquid‐crystalline compounds. The origin of the stripe patterns can be ascribed to an extremely large bent elastic constant K33. In addition, we succeeded in controlling the pattern by the following two methods: 1) the stripe disappears by a trans–cis photoisomerization upon UV light irradiation and reappears upon light termination, and 2) the stripe pattern is stabilized over the whole nematic phase, at approximately 10 °C, by polymerization of the compounds.
Catalytic Oxidation of Biorefinery Lignin to Value‐added Chemicals to Support Sustainable Biofuel Production
Authors: Ma Ruoshui , Xu Yan , Zhang Xiao 
Published: October 2014

AbstractTransforming plant biomass to biofuel is one of the few solutions that can truly sustain mankind’s long‐term needs for liquid transportation fuel with minimized environmental impact. However, despite decades of effort, commercial development of biomass‐to‐biofuel conversion processes is still not an economically viable proposition. Identifying value‐added co‐products along with the production of biofuel provides a key solution to overcoming this economic barrier. Lignin is the second most abundant component next to cellulose in almost all plant biomass; the emerging biomass refinery industry will inevitably generate an enormous amount of lignin. Development of selective biorefinery lignin‐to‐bioproducts conversion processes will play a pivotal role in significantly improving the economic feasibility and sustainability of biofuel production from renewable biomass. The urgency and importance of this endeavor has been increasingly recognized in the last few years. This paper reviews state‐of‐the‐art oxidative lignin depolymerization chemistries employed in the papermaking process and oxidative catalysts that can be applied to biorefinery lignin to produce platform chemicals including phenolic compounds, dicarboxylic acids, and quinones in high selectivity and yield. The potential synergies of integrating new catalysts with commercial delignification chemistries are discussed. We hope the information will build on the existing body of knowledge to provide new insights towards developing practical and commercially viable lignin conversion technologies, enabling sustainable biofuel production from lignocellulosic biomass to be competitive with fossil fuel.
Sex‐specific winter distribution in a sexually dimorphic shorebird is explained by resource partitioning
Authors: Duijns Sjoerd , van Gils Jan A. , Spaans Bernard , ten Horn Job , Brugge Maarten , Piersma Theunis 
Published: October 2014

AbstractSexual size dimorphism (SSD) implies correlated differences in energetic requirements and feeding opportunities, such that sexes will face different trade‐offs in habitat selection. In seasonal migrants, this could result in a differential spatial distribution across the wintering range. To identify the ecological causes of sexual spatial segregation, we studied a sexually dimorphic shorebird, the bar‐tailed godwitLimosa lapponica, in which females have a larger body and a longer bill than males. With respect to the trade‐offs that these migratory shorebirds experience in their choice of wintering area, northern and colder wintering sites have the benefit of being closer to the Arctic breeding grounds. According to Bergmann's rule, the larger females should incur lower energetic costs per unit of body mass over males, helping them to winter in the cold. However, as the sexes have rather different bill lengths, differences in sex‐specific wintering sites could also be due to the vertical distribution of their buried prey, that is, resource partitioning. Here, in a comparison between six main intertidal wintering areas across the entire winter range of thelapponicasubspecies in northwest Europe, we show that the percentage of females between sites was not correlated with the cost of wintering, but was positively correlated with the biomass in the bottom layer and negatively with the biomass in the top layer. We conclude that resource partitioning, rather than relative expenditure advantages, best explains the differential spatial distribution of male and female bar‐tailed godwits across northwest Europe.
Applications of Carbohydrate‐Based Organocatalysts in Enantioselective Synthesis
Authors: Faísca Phillips Ana Maria 
Published: October 2014

AbstractCarbohydrates have been widely used for stereochemical control, either as chiral auxiliaries or as ligands. Their natural abundance and rigidity of structure, together with the presence of many functional groups, have also in recent years made them attractive chiral modular units for the assembly of bifunctional organocatalysts. Applications have ranged from the more complex bifunctional carbohydrate‐based amine–(thio)ureas and prolinamides to simple amino alcohols. The presence of many hydroxy groups and their consequent water solubility has allowed for the study of reactions in aqueous media. Nowadays they have been applied to many reactions such as the aldol, Michael, Stetter, Biginelli, Morita–Baylis–Hillman, decarboxylative Mannich and other reactions, and even to the multistep synthesis of known drugs. This review provides an overview of developments in this field in the period from 2009 to mid‐2014.
A Highly Sensitive Hydrogen Peroxide Biosensor Based on Hemoglobin Immobilized on Cadmium Sulfide Quantum Dots/Chitosan Composite Modified Glassy Carbon Electrode
Authors: Butwong Nutthaya , Zhou Lin , Moore Eric , Srijaranai Supalax , Luong John H. T. , Glennon Jeremy D. 
Published: October 2014

AbstractAn L‐cysteine capped cadmium sulfide‐chitosan nanocomposite has been synthesized, characterized and used for surface modification of a glassy carbon electrode. With direct electron transfer, hemoglobin (Hb) adsorbed strongly on the nanocomposite and displayed excellent bioelectrocatalysis for H2O2. The biosensor was capable of reducing H2O2 at −0.35 V, with a detection limit of 3.13 nM, linearity in the range of 15 nM to 10 µM and a response time of less than 2 s. The MichaelisMenten constant (KM) was 0.57 nM, attesting high bioelectrocatalysis of immobilized Hb for H2O2. Reproducibility of the fabrication method was very satisfactory with a relative standard deviation of 5.3 %. The biosensor lost only 6.5 % of its original response after 7 days when stored in a pH 7.4 PBS at 4 °C.
Sensitive Detection of Transcription Factor Kaiso via Self‐Assembly of DNA on an Electrode Surface
Authors: Li Xiaoxi , Yang Nana , Zhang Yuanyuan , Li Hao , Yin Tingting , Sun Lizhou , Li Genxi 
Published: October 2014

AbstractHere we report a novel method based on the assembly of DNA nanowire on an electrode surface for amplified detection of an essential transcription factor protein named Kaiso, the aberrant expression of which is involved in various kinds of tumors. This method allows efficient bioanalysis of Kaiso in three breast cancer cell lines to be conducted, thus the malignancy degree of the cell lines can be evaluated by using this method. The proposed method also shows desirable sensitivity, high selectivity, and excellent reproducibility, implying that this method may hold considerable potential for clinical diagnosis in the future.
Coextraction and PCR Based Analysis of Nucleic Acids From Formalin‐Fixed Paraffin‐Embedded Specimens
Authors: Ghatak Souvik , sanga Zothan , Pautu Jeremy L. , Kumar Nachimuthu Senthil 
Published: October 2014

BackgroundRetrospective studies of archived human specimens, with known clinical follow‐up, are used to identify predictive and prognostic molecular markers of disease. Due to biochemical differences, however, formalin‐fixed paraffin embedded (FFPE) DNA and RNA have generally been extracted separately from either different tissue sections or from the same section by dividing the digested tissue. Our optimized co‐extraction approach provides the option of collecting DNA, which would otherwise be discarded or degraded, for additional or subsequent studies because of the high importance and less availability of clinical FFPE specimen.MethodsCoextraction of DNA and RNA from a single gastric cancer FFPE specimen was optimized by using TRIzol and purifying DNA from the lower aqueous and RNA from the upper organic phases. The protocol involves modification of incubation period for 30 min with proteinase K in glycin‐tris‐ethylenediamine tetra acetic acid buffer before adding TRIzol.ResultsAll samples tested successfully performed semiquantitative gene expression by reverse transcriptase PCR. The quantity and quality of DNA from FFPE samples was high which resulted in successful PCR amplification. The isolated DNA also aided in detection of Helicobacter pylori by amplifying the ribosomal 16S gene in a multiplex PCR reaction along with cagA.ConclusionThese results show that the RNA/DNA isolated by this method can be used for easy clinical diagnosis of disease‐related gene expression as well as mutation and pathogen detection from a homogenous population of tumor cells.
Establishment and Evaluation of a One‐Step Microplate Chemiluminescence Immunoassay to Detect IgG Antibody Against Treponema Pallidum
Authors: Liu Lijuan , Xie Yuling , Dai Zhenxian , Zhuo Chuanshang , Wu Yushui 
Published: October 2014

BackgroundThe serological detection of specific antibodies against Treponema pallidum is of particular importance in the diagnosis of syphilis. The chemiluminescence immunoassay (CLIA) has been widely used for clinical diagnosis because they remit no radical waste products, cause no enzyme precipitation, and exhibit an excellent sensitivity.MethodsA one‐step CLIA was established to detect T. pallidum IgG antibody based on microplate coated with a mixture of recombinant T. pallidum antigens TpN15, TpN17, and TpN47. The Chinese national reference substances standard panel for T. pallidum diagnosis was applied to test the accuracy, stability, interference, and cross‐reactivity of the established CLIA. The validation of efficacy for clinical application was performed by comparing the established method with the marketed T. pallidum particle agglutination (TPPA) kit and the Abbott ARCHITEC Auto System.ResultsThe established method met the requirement of the Chinese national reference substances standard for T. pallidum diagnosis. When compared with TPPA (n = 1,052), the specificity, sensitivity, and overall concordance were 99.7%, 99.0%, and 98.8% respectively, showing a great agreement with a kappa value of 0.81. When compared with the Abbott ARCHITEC Auto System (n = 352), the results showed that the specificity, sensitivity, and overall concordance were 98.6.0%, 96.6% and 98.6% respectively, and a high‐degree agreement was observed (kappa value = 0.95).ConclusionThe established rapid, specific, sensitive, and stable microplate CLIA method to detect IgG antibody against T pallidum will provide an efficient alternative to the treponemal tests and wide application in clinical laboratory.
Parallelized multilevel fast multipole algorithm for scattering by objects with anisotropic impedance surfaces
Authors: Zhang Kedi , Jin Jian‐Ming 
Published: October 2014

SUMMARYA parallelized multilevel fast multipole algorithm (MLFMA) is presented for simulating electromagnetic scattering from complex targets with anisotropic impedance surfaces. By employing both surface electric and magnetic currents as unknowns and weakly enforcing the anisotropic impedance boundary condition, a combined integral equation is formulated to generate a set of well‐conditioned linear systems to be solved by MLFMA. To further improve the iterative convergence of the linear systems, a parallel sparse approximate inverse preconditioner is constructed from the near‐field interaction of the system matrix. The MLFMA is parallelized to enable computation on a large number of processors for large‐scale problems. Several numerical examples are presented to validate the algorithm and demonstrate its accuracy, scalability, and capability in handling large complex objects with anisotropic impedance surfaces. Copyright © 2014 John Wiley & Sons, Ltd.
Performance and stability analysis of monolayer single‐walled carbon nanotube interconnects
Authors: Zhao Wen‐Sheng , Wang Gaofeng , Hu Jun , Sun Lingling , Hong Hui 
Published: October 2014

SummaryIn this paper, the monolayer single‐walled carbon nanotube (SWCNT) interconnects are modeled and investigated comprehensively. On the basis of the ratio of the resistance–capacitance values between Cu and SWCNT interconnects, it is demonstrated that the monolayer SWCNT interconnect can provide comparable and even better performance than Cu wire at the 19 nm technology node and beyond. Furthermore, the relative stability analysis is carried out for the monolayer SWCNT interconnects by investigating the relative position of the Nyquist diagram with respect to the critical point (−1, 0). It is shown that the relative stability can be improved by increasing the length and decreasing the SWCNT diameter. Meanwhile, the relative stability also can be improved with the technology advancement. Finally, the crosstalk effects are studied on the basis of the tri‐interconnect architecture. As the monolayer SWCNT interconnects possess much smaller capacitance, the signal integrity can be improved, with the peak noise voltage suppressed greatly. Copyright © 2014 John Wiley & Sons, Ltd.
Elemental composition of serpentine plants depends on habitat affinity and organ type
Authors: DeHart Kyle S. , Meindl George A. , Bain Daniel J. , Ashman Tia‐Lynn 
Published: October 2014

AbstractSerpentine soils represent a stressful growing environment for most plants due to a number of edaphic factors, including low concentrations of plant nutrients and high concentrations of heavy metals. Plants in these environments range from weakly resistant to strictly endemic, yet it remains unclear whether serpentine habitat affinity affects plant chemistry, including elemental distribution among various organs. We address this knowledge gap using three confamilial pairs of endemic and non‐endemic plants. First, we determined total and phytoavailable soil concentrations of four nutrients (Ca, Mg, P, K) and three heavy metals (Co, Cr, Ni) across 11 serpentine study sites. Next, we determined the concentrations of these elements in leaves, flowers, and seeds in plants of each species growing on serpentine soil. Soils at the study sites were characteristically high in concentrations of Mg, Ni, Co and Cr, and low in K, P and Ca relative to non‐serpentine soils. Habitat affinity was critical in determining the organ concentrations of Ca, Mg, K, and Co, although concentration often varied by organ type. Relative to non‐endemics, endemics had higher concentrations of Mg and K across all organ types, whereas Ca concentrations were higher for non‐endemics in the leaves but equal for the two reproductive organs. While no difference was observed in Ni or Cr concentrations, endemics contained 56% less Co than non‐endemics across all organ types. These results suggest that serpentine endemics are more effective at acquiring potentially limiting nutrients compared to non‐endemic species, but both endemic and non‐endemic plants exclude most phytotoxic heavy metals. Therefore, growth on serpentine requires common physiological responses of all plants, though high variation in uptake of some key nutrients and exclusion of some metals may reflect differential adaptation to serpentines by non‐endemic and endemic plants.
End Group Modification of Polynorbornenes
Authors: Lin Ting‐Wei , Chou Chih‐Ming , Lin Nai‐Ti , Lin Cheng‐Lan , Luh Tien‐Yau 
Published: October 2014

Polynorbornenes with allylic acetoxy terminus are obtained by ring‐opening metathesis polymerization of the norbornene derivatives followed by quenching with 1,4‐diacetoxy‐2Z‐butene. Treatment of these polymers with a range of nucleophiles in the presence of a Pd‐catalyst gives the corresponding polynorbornenes bearing different end groups. The same protocol is used to modify the end groups of polymeric ladderphanes. Incorporation of an end‐group‐modified polynorbornene on indium tin oxide (ITO) surface perturbs the electrochemical properties of the ITO electrode.
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Effects of Thermal Annealing and Solvent Annealing on the Morphologies and Properties of Poly(3‐hexylthiophene) Nanowires
Authors: Fu Chuan‐Min , Jeng Kai‐Sheng , Li Yu‐Hsun , Hsu Yuan‐Chen , Chi Mu‐Huan , Jian Wen‐Bin , Chen Jiun‐Tai 
Published: October 2014

In recent years, poly(3‐hexylthiophene) (P3HT) nanowires have attracted great interest because of their unique physical and electronic properties. The annealing effects on the properties and morphologies of P3HT nanowires, however, are still not fully understood. In this work, the effects of thermal annealing and solvent annealing on the morphologies and crystallinities of P3HT nanowires prepared by the whisker method are studied. P3HT is first dissolved in heated p‐xylene, followed by a cooling process to room temperature, and P3HT nanowires are formed by self‐assembly. The crystallinities of the P3HT nanowires are observed to increase by both thermal annealing and solvent annealing, as confirmed by differential scanning calorimetry and X‐ray diffraction. The device performances of organic field‐effect transistors based on the annealed nanowires are also examined. After annealing, an enhancement of the charge mobility by one order is observed.
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Die Temperatur bei der Bestimmung der Parameter TOC und TNb
Authors: Hupach Sascha 
Published: October 2014

AbstractBei der TOC‐Bestimmung mit katalytischer Verbrennungsoxidation bleiben anorganische Stoffe, darunter Salze, auf dem Katalysator zurück. Sie schädigen ihn, wenn sie bei zu hoher Verbrennungstemperatur schmelzen. Oxidation bei 680 °C setzt die organischen Stoffe vollständig um, Salzschmelzen bleiben aus.
Biosynthese der Phenazine
Authors: Diederich Christina , Leypold Mario , Breinbauer Rolf , Blankenfeldt Wulf 
Published: October 2014

AbstractPhenazine sind farbige Verbindungen synthetischen und natürlichen Ursprungs. Sie standen am Anfang der synthetischen Farbenindustrie und führten zu wichtigen Entdeckungen in der Mikrobiologie. Ihre strukturelle Symmetrie spiegelt sich in ihrer Biosynthese wider.
Nitrit: Raus aus der Wurst?
Authors: Osterath Brigitte 
Published: October 2014

AbstractNitritpökelsalz macht Fleisch schmackhaft, appetitlich rot und schützt vor Keimen. Aber es steht im Verdacht, Krebs zu erzeugen. Reicht ein Verdacht aus, um der Fleischindustrie ein wichtiges Hilfsmittel wegzunehmen?
Sorgenkind systemischer Pflanzenschutz
Authors: Groß Michael 
Published: October 2014

AbstractDas Beizen von Saatgut mit Pflanzenschutzmitteln galt ursprünglich als umweltfreundliche Alternative zum Sprühen. Dann wurden die Mittel mit dem Bienensterben in Verbindung gebracht, und jetzt befürchten Biologen, dass die Anreicherung in Böden und Gewässern sogar Vögeln und Fischen schadet.