bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of a Yeast-mediated Biological Fuel Cell
Authors: Gunawardena Anuradh , Fernando Sandun , To Filip
Published: October 2008

Saccharomyces cerevisiae present in common Baker’s yeast was used in a microbial fuel cell in which glucose was the carbon source. Methylene blue was used as the electronophore in the anode compartment, while potassium ferricyanide and methylene blue were tested as electron acceptors in the cathode compartment. Microbes in a mediator-free environment were used as the control. The experiment was performed in both open and closed circuit configurations under different loads ranging from 100 kΩ to 400Ω. The eukaryotic S. cerevisiae-based fuel cell showed improved performance when methylene blue and ferricyanide were used as electron mediators, rendering a maximum power generation of 146.71±7.7 mW/m3. The fuel cell generated a maximum open circuit voltage of 383.6±1.5 mV and recorded a maximum efficiency of 28±1.8 % under 100 kΩ of external load.
A DFT Study on Deactivation of Triplet Excited State Riboflavin by Polyphenols
Authors: Ji Hong-Fang , Shen Liang
Published: October 2008

The deactivation of triplet excited state riboflavin by polyphenols, e.g. rutin and catechin, was studied on the basis of density functional theory calculations. The results show that the H-atom transfer pathway is more feasible on thermodynamic grounds in comparison with the direct energy transfer or direct electron transfer pathways involved in the triplet excited state riboflavin deactivation by rutin/catechin. The findings are helpful to understand the protective effect of polyphenols against the riboflavin induced photosensitizing damage.
Characterizing the Anti-HIV Activity of Papuamide A
Authors: Andjelic Cynthia D. , Planelles Vicente , Barrows Louis R.
Published: October 2008

Papuamide A is representative of a class of marine derived cyclic depsipeptides, reported to have cytoprotective activity against HIV-1 in vitro. We show here that papuamide A acts as an entry inhibitor, preventing human immunodeficiency virus infection of host cells and that this inhibition is not specific to R5 or X4 tropic virus. This inhibition of viral entry was determined to not be due to papuamide A binding to CD4 or HIV gp120, the two proteins involved in the cell-virus recognition and binding. Furthermore, papuamide A was able to inhibit HIV pseudotype viruses expressing envelope glycoproteins from vesicular stomatitis virus or amphotropic murine leukemia virus indicating the mechanism of viral entry inhibition is not HIV-1 envelope glycoprotein specific. Time delayed addition studies with the pseudotyped viruses show that papuamide A inhibits viral infection only at the initial stage of the viral life cycle. Additionally, pretreatment studies revealed that the virus, and not the cell, is the target of papuamide A’s action. Together, these results suggest a direct virucidal mechanism of HIV-1 inhibition by papuamide A. We also demonstrate here that the other papuamides (B-D) are able to inhibit viral entry indicating that the free amino moiety of 2,3-diaminobutanoic acid residue is not required for the virucidal activity.
A New Method to Define the VI-Ts Diagram Using Subpixel Vegetation and Soil Information: A Case Study over a Semiarid Agricultural Region in the North China Plain
Authors: Sun Zhigang , Wang Qinxue , Matsushita Bunkei , Fukushima Takehiko , Ouyang Zhu , Watanabe Masataka
Published: October 2008

The VI-Ts diagram determined by the scatter points of the vegetation index (VI) and surface temperature (Ts) has been widely applied in land surface studies. In the VI-Ts diagram, dry point is defined as a pixel with maximum Ts and minimum VI, while wet point is defined as a pixel with minimum Ts and maximum VI. If both dry and wet points can be obtained simultaneously, a triangular VI-Ts diagram can be readily defined. However, traditional methods cannot define an ideal VI-Ts diagram if there are no full ranges of land surface moisture and VI, such as during rainy season or in a period with a narrow VI range. In this study, a new method was proposed to define the VI-Ts diagram based on the subpixel vegetation and soil information, which was independent of the full ranges of land surface moisture and VI. In this method, a simple approach was firstly proposed to decompose Ts of a given pixel into two components, the surface temperatures of soil (Tsoil) and vegetation (Tveg), by means of Ts and VI information of neighboring pixels. The minimum Tveg and maximum Tsoil were then used to determine the wet and dry points respectively within a given sampling window. This method was tested over a 30 km × 30 km semiarid agricultural area in the North China Plain through 2003 using Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) and MODerate-resolution Imaging Spectroradiometer (MODIS) data. The wet and dry points obtained from our proposed method and from a traditional method were compared with those obtained from ground data within the sampling window with the 30 km × 30 km size. Results show that Tsoil and Tveg can be obtained with acceptable accuracies, and that our proposed method can define reasonable VI-Ts diagrams over a semiarid agricultural region throughout the whole year, even for both cases of rainy season and narrow range of VI.
Trait anger and anger expression style in children's risky decisions
Authors: Gambetti Elisa , Giusberti Fiorella
Published: October 2008

In this study, 104 children completed a task, measuring risk decision‐making, and the State‐Trait Anger Expression Inventory for Children and Adolescents . Subjects were also asked to evaluate the degree of danger, benefit, fun and fear perceived for each risky choice. Analyses indicated that (a) risk decision‐making was predicted by both trait anger and outward expression of anger; (b) appraisal of danger fully mediated the relationship between trait anger and risk; (c) perceptions of benefit, scare and fun partially mediated the relationship between trait anger and risk; and (d) appraisal of danger partially mediated the relationship between outward expression of anger and risk decision‐making. The results provide evidence for a relationship between dispositional anger and risk decision‐making during childhood, suggesting a possible explanation of the mechanisms below. In particular, risk decision‐making can be viewed as the output of cognitive and emotive processes, linked to dispositional anger that leads children to be amused, optimistic and fearless in potentially risky situations. These findings substantiate the importance of incorporating cognitive and emotive factors in theories that seek to explain the relationship between personality traits and risk decision‐making across a broad age range. Aggr. Behav. 35:14–23, 2009. © 2008 Wiley‐Liss, Inc.
The Remarkable Thermal Stability of Amorphous In‐Zn‐O Transparent Conductors
Authors: Taylor Matthew P. , Readey Dennis W. , van Hest Maikel F. A. M. , Teplin Charles W. , Alleman Jeff L. , Dabney Matthew S. , Gedvilas Lynn M. , Keyes Brian M. , To Bobby , Perkins John D. , Ginley David S.
Published: October 2008

Transparent conducting oxides (TCOs) are increasingly critical components in photovoltaic cells, low‐e windows, flat panel displays, electrochromic devices, and flexible electronics. The conventional TCOs, such as Sn‐doped In2O3, are crystalline single phase materials. Here, we report on In‐Zn‐O (IZO), a compositionally tunable amorphous TCO with some significantly improved properties. Compositionally graded thin film samples were deposited by co‐sputtering from separate In2O3 and ZnO targets onto glass substrates at 100 °C. For the metals composition range of 55–84 cation% indium, the as‐deposited IZO thin films are amorphous, smooth (RRMS < 0.4 nm), conductive (σ ∼ 3000 Ω−1 · cm−1), and transparent in the visible (TVis > 90%). Furthermore, the amorphous IZO thin films demonstrate remarkable functional and structural stability with respect to heating up to 600 °C in either air or argon. Hence, though not completely understood at present, these amorphous materials constitute a new class of fundamentally interesting and technologically important high performance transparent conductors.
Fabrication of Reversibly Crosslinkable, 3‐Dimensionally Conformal Polymeric Microstructures
Authors: Connal Luke A. , Vestberg Robert , Hawker Craig J. , Qiao Greg G.
Published: October 2008

Multifaceted porous materials were prepared through careful design of star polymer functionality and properties. Functionalized core crosslinked star (CCS) polymers with a low glass transition temperature (Tg) based on poly(methyl acrylate) were prepared having a multitude of hydroxyl groups at the chain ends. Modification of these chain ends with 9‐anthracene carbonyl chloride introduces the ability to reversibly photocrosslink these systems after the star polymers were self‐assembled by the breath figure technique to create porous, micro‐structured films. The properties of the low Tg CCS polymer allow for the formation of porous films on non‐planar substrates without cracking and photo‐crosslinking allows the creation of stabilized honeycomb films while also permitting a secondary level of patterning on the film, using photo‐lithographic techniques. These multifaceted porous polymer films represent a new generation of well‐defined, 3D microstructures.
Intermolecular Interactions of Perylene diimides in Photovoltaic Blends of Fluorene Copolymers: Disorder Effects on Photophysical Properties, Film Morphology and Device Efficiency
Authors: Keivanidis Panagiotis E. , Howard Ian A. , Friend Richard H.
Published: October 2008

In the present work, we correlate the photophysical and photovoltaic properties with the respective film morphologies of three different blends made of the fluorene copolymers poly(9,9′‐dioctylfluorene‐co‐benzothiadiazole) (F8BT), poly[9,9′‐dioctylfluorene‐co‐N‐(4‐butylphenyl)diphenylamine] (TFB), and poly[9,9′‐dioctyfluorene‐co‐bis‐N,N′‐(4‐butylphenyl)‐bis‐N,N‐phenyl‐1,4‐phenylenediamine] (PFB) when blended with a perylene tetracarboxylic diimide (PDI) derivative. Additional photophysical studies in reference PDI blends of the electronically inert poly(styrene) matrix address the enhanced PDI intermolecular solid‐state interactions. We resolve the process of resonance energy transfer from excited polymer hosts to PDI and the process of photoinduced hole transfer from PDI to the polymer hosts. We deduce the efficiency of charge‐transfer PDI photoluminescence (PL) quenching and we discuss the power‐law PL kinetics seen in the as‐spun systems. Next we determine the dependence of the device external quantum efficiency (EQE) of these blends, in a range of annealing temperatures and PDI loadings. Differential scanning calorimetry enables precise selection of annealing temperatures. Optical microscopy shows that annealing enhances the order characteristics in the PDI aggregates in the F8BT:PDI system. In the case of the TFB:PDI and PFB:PDI blends, AFM studies suggest the formation of PDI‐rich domains on the film/air interface. The degree of order in the π–π stacking of the PDI monomers is inferred by the UV–Vis and PL spectra of the blends. The extent of order characteristics in PDI aggregates is correlated with the thermal properties of the hosts that control PDI molecular mobility upon annealing. The efficient dispersion of disrupted PDI crystallites is proposed to form appropriate percolation networks that favor balanced extraction of photogenerated carriers.
Superoleophilic and Superhydrophobic Inverse Opals for Oil Sensors
Authors: Li Huiling , Wang Jingxia , Yang Lianming , Song Yanlin
Published: October 2008

An inverse opal with both superoleophilic (oil contact angle (CA), 5.1° ± 1.2°) and superhydrophobic (water CA, 153.8° ± 1.2°) properties is fabricated using a phenolic resin (PR) as precursor and poly(styrene‐methyl methacrylate‐acrylic acid) (poly(St‐MMA‐AA)) colloidal crystals as templates. The stopband of the inverse opal can shift reversibly upon sorption of oils, whereby the peak position is a linear function of the refractive index of the adsorbed oil, e.g., a variation in refractive index of 0.02 will result in a stopband shift of 26 nm. Therefore, the inverse opals show a high sensitivity and selectivity for different petroleum oils. Moreover, as‐prepared PR inverse opals show excellent oil‐sensing stability in cyclic sorption experiments, which suggests a promising and economical alternative to traditional oil‐sensing materials, and will provide a new approach to in situ petroleum monitoring and detection.
Spatially Graded Nanostructured Chiral Films as Tunable Circular Polarizers
Authors: Krause Kathleen M. , Brett Michael J.
Published: October 2008

In this paper, we introduce a simple single‐step method for creating spatially graded helical nanostructured thin films. The films mimic some of the interesting polarization and coloration properties found in nature and enhance the application prospects for helically structured thin films. Our helical nanostructures, fabricated using a variant of the glancing angle deposition technique (GLAD), are spatially graded with thicknesses that vary by several microns across substrate lengths of several tens of centimeters. These thickness gradations are predicted by simulation and verified by scanning electron microscopy (SEM). The resultant films act as Bragg multilayers and can be employed as optical filters which not only preferentially transmit one handedness of circularly polarized light, but also allow for spatially determined frequency tunability. Through spectroscopic measurements, we demonstrate that when appropriate deposition conditions are chosen these nanostructures exhibit strong polarization selectivity, concurrent with excellent frequency tunability. The preferentially transmitted peak wavelength can be changed from approximately 620 to 690 nm by translating the film over a spatial distance of 30 mm. These graded nanostructures can be incorporated into photonic and sensing devices. The graded helical nanostructures may also be useful for providing a graded scaffolding to support liquid crystals.
Benzimidazolium‐Pyrazole‐Palladium(II) Complexes: New and Efficient Catalysts for Suzuki, Heck and Sonogashira Reactions
Authors: Li Fuwei , Hor T. S. Andy
Published: October 2008

Three unsymmetrical benzimidazolium‐pyrazole N‐N ligands 2‐(1‐propylbenzimidazolylmethyl)‐3,5‐di‐R‐pyrazole (R=H, Me, t‐Bu) have been conveniently prepared and structurally analyzed. The solid lattice packing of the R=Me compound at 223 K reveals one‐dimensional “zig‐zag” water chains stabilized by organic molecular channels through N⋅⋅⋅HO and OH⋅⋅⋅O bonding. These hybrid ligands add to palladium(II) to give high yields of air‐stable complexes that are fully characterized by NMR, ESI, and X‐ray single‐crystal crystallography. They are active Suzuki catalysts at room temperature towards cross‐coupling of unactivated aryl bromides and 5‐ or 6‐membered heteroaryl bromides with arylboronic acids with turnover frequencies (TOF) reaching as high as 60,000 h−1. Their catalytic efficiency is significantly better than that of the CN carbene‐imidazole analogue. These catalysts are also active in Heck and Sonogashira cross‐coupling reactions of aryl bromides giving the desired products in good yields. These results suggested that these Pd(II) complexes with N‐based hybrid ligands are versatile and efficient catalysts for different types of cross‐coupling reactions under aerobic conditions.
An Efficient and Practical Sequential One‐Pot Synthesis of Suprofen, Ketoprofen and Other 2‐Arylpropionic Acids
Authors: Neumann Helfried , Brennführer Anne , Beller Matthias
Published: October 2008

A novel sequential double carbonylation to synthesize anti‐inflammatory drugs such as Ketoprofen and Suprofen has been developed. Starting from easily available aryl halides and arylboronic acids a one‐pot carbonylative Suzuki and hydroxycarbonylation reaction sequence proceeds in good selectivity and high yield in the presence of the palladium/cataCXium® A catalyst system. Applying optimized conditions different 2‐arylpropionic acids were synthesized in good yields.
Simple, Highly Enantioselective Access to Quaternary 1,3,4,4‐Tetrasubstituted β‐Lactams from Amino Acids: A Solid‐Phase Approach
Authors: Pérez‐Faginas Paula , Aranda M. Teresa , Coady Laoise , García‐López M. Teresa , González‐Muñiz Rosario
Published: October 2008

An operationally simple four‐step procedure for the solid‐phase synthesis of chiral (3S,4S)‐1,3,4,4‐tetrasubstituted β‐lactams is described. The key step for the four‐membered ring formation consisted in the enantioselective phosphazene base‐assisted cyclization of resin‐bound N‐(alkyl)‐N‐[(S)‐2‐chloropropionyl]amino acid derivatives. A low‐epimerization process during the incorporation of the 2S‐chloropropionyl moiety into the N‐alkylamino acid resins was crucial for the final stereochemical outcome, since the 3,4‐stereochemistry was exclusively dictated by the configuration of this moiety. To evaluate the scope of this procedure a small library of quaternary, highly functionalized β‐lactams has been generated.
Characterization of Helicobacter pylori α1,2‐Fucosyltransferase for Enzymatic Synthesis of Tumor‐Associated Antigens
Authors: Stein Daniel B. , Lin Yu‐Nong , Lin Chun‐Hung
Published: October 2008

The α1,2‐fucosyltransferase (α1,2‐FucT) from Helicobacter pylori catalyzes the fucosylation of acceptor oligosaccharides at the C2‐OH of terminal Galβ units. The enzyme from strain NCTC11639 was evaluated for its ability to synthesize cancer‐associated antigens. The α1,2‐FucT was determined to be active over a pH range between 4.0 and 8.0 with the optimum occurring at pH 5.0. Although a divalent metal ion cofactor was not required for catalysis, enhancement of the enzyme activity was detected upon supplement with Mn2+. Detailed substrate specificity analysis revealed that α1,2‐FucT can catalyze the fucosylation of a wide variety of oligosaccharide substrates. The α1,2‐FucT preferentially fucosylated type 1 structure (Galβ1‐3GlcNAc)‐containing glycans over type 2 structure (Galβ1‐4GlcNAc)‐containing glycans. The Lewisa trisaccharide [Galβ1‐3(Fucα1‐4)GlcNAc] was found to be the best acceptor. The only exception was that the Lewisx pentasaccharide LNFP III [Galβ1‐4(Fucα1‐3)GlcNAcβ1‐3Galβ1‐4Glc] was favored over the Lewisa analogue LNFP II [Galβ1‐3(Fucα1‐4)GlcNAcβ1‐3Galβ1‐4Glc]. Furthermore, the enzyme exhibited high levels of fucosylation with the type 3/4 disaccharide (Galβ1‐3GalNAc). Enzymatic hydrolysis of the donor substrate, guanosine‐5′‐diphospho‐β‐L‐fucose (GDP‐fucose), could be observed in the absence of oligosaccharide substrate. This hydrolysis was completely shifted to an efficient fucosyl transfer in the presence of a substrate sugar. Finally, the H. pylori α1,2‐FucT was successfully used in combination with its α1,3‐FucT counterpart to synthesize the Lewisy tetrasaccharide [Fucα1‐2Galβ1‐4(Fucα1‐3)GlcNAc] from LacNAc (Galβ1‐4GlcNAc) in a milligram scale one‐pot reaction.
Toward an enhanced understanding and implementation of photopolymerization reactions
Authors: Bowman Christopher N. , Kloxin Christopher J.
Published: October 2008

Photopolymerization reactions proceed rapidly at ambient conditions and are able to exhibit both temporal and spatial control, nevertheless their full potential has been limited by a lack of understanding of the polymerization kinetics and polymer network evolution as well as a lack of custom, functional monomers, and polymerization mechanisms. For the last 15 years, our group has sought to address these limitations by reaction engineering at both the fundamental and applied levels with a focus on increasing the understanding, potential, and implementation of photopolymerization reactions. In particular, we have modeled and experimentally validated the complex spatially dependent polymerization kinetics and network heterogeneity, and we have implemented these systems for applications improvement or development in lithography, microdevice fabrication, biomaterials, biodetection, dental materials, and surface coatings. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Life expectancy in Gaucher disease type 1
Authors: Weinreb Neal J. , Deegan Patrick , Kacena Katherine A. , Mistry Pramod , Pastores Gregory M. , Velentgas Priscilla , vom Dahl Stephan
Published: October 2008

We estimated life expectancy at birth for Gaucher disease type 1 (GD1) patients by comparing survival data from GD1 patients enrolled in ICGG Gaucher Registry to the U.S. population using standard life table methods. 2,876 GD1 patients had 102 reported deaths in 13,509 person‐years of follow‐up. Estimated life expectancy at birth was 68 y, compared with 77 y in reference population; splenectomized patients, 64 y; nonsplenectomized, 72 y. Causes of death for 63/102 patients were malignancy (17/63), cardiovascular (11/63), and cerebrovascular (8/63). Estimated life expectancy at birth for GD1 patients was ∼9 y less than reference population. Malignancies did not contribute to shortened life expectancy. Am. J. Hematol., 2008. © 2008 Wiley‐Liss, Inc.
[2.2]Paracyclophanes in Polymer Chemistry and Materials Science
Authors: Hopf Henning
Published: October 2008

After a long period as model compounds in basic research [2.2]paracyclophanes are quickly gaining in practical importance. They can be incorporated into numerous polymeric systems in which they either lose (the so‐called Parylenes) or retain their layered structure, and they can be used for the construction of unsaturated molecular scaffolds characterized not only by conventional (lateral) π‐electron overlap but also by cofacial π‐electron interactions. Surfaces generated from and with [2.2]paracyclophanes possess interesting biological, photophysical, and optoelectronic properties.
Toughened epoxy resin matrix for a membrane shell by wet filament winding
Authors: Zhou Wenying , Qi Shuhua , Ai Tao , Zhao Hongzhen , Zhang Mingtao , Li Wenquan , Lau Eva
Published: October 2008

A toughened epoxy resin matrix was obtained with a reactive toughening agent and methyl hexahydrophthalic anhydride as a curing agent. The mechanical properties of the modified epoxy resin and its glass‐fiber‐reinforced composites were investigated systematically. The modified epoxy resin matrix possessed many good properties, including a high flexural strength (138 MPa), high elongation at break (5.2%), low viscosity, long pot life at room temperature, and good water resistance. In addition, the glass‐fiber‐reinforced composites showed a high strength conversion ratio of the glass fiber (86.7%) and good fatigue resistance. The results demonstrated that the modified epoxy resin matrix is very suitable for applications in reverse osmosis membrane shell products fabricated with wet filament winding for water treatment. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Juvenile hormone acid methyl transferase is a key regulatory enzyme for juvenile hormone synthesis in the Eri silkworm, Samia cynthica ricini
Authors: Sheng Zhentao , Ma Li , Cao Mei‐Xun , Jiang Rong‐Jing , Li Sheng
Published: October 2008

During the period of adult emergence in the Eri silkworm, Samia cynthia ricini, the corpora allata (CA) are apparently reactivated in females, but not males. This creates a significant sexual dimorphism in juvenile hormone (JH) synthesis by CA. To determine the underlying molecular mechanisms in this process, we cloned cDNAs of two enzymes involved in the JH synthesis pathway: 3‐hydroxy‐3‐methylglutaryl CoA reductase (HMGR) and juvenile hormone acid methyl transferase (JHAMT). Both Samcri‐HMGR and ‐JHAMT mRNAs were detected in CA almost exclusively. However, their expression patterns were different from each other. During the period of adult emergence, Samcri‐HMGR was expressed in CA at a constantly high level suggesting it plays little role for the regulation of JH synthesis. In contrast, the patterns of both Samcri‐JHAMT mRNA level and enzyme activity were closely correlated with the patterns of JH synthesis, CA reactivation, and sexual dimorphism of JH synthesis. In addition, JHAMT mRNA levels were paralleled JH synthesis in the fifth‐instar larvae of S. cynthia ricini and the pharate adults of the silkworm Bombyx mori. We infer from these results that JHAMT is a key regulatory enzyme for JH synthesis in the Eri silkworm. Arch. Insect Biochem. Physiol. 69:143‐154, 2008. © 2008 Wiley‐Liss, Inc.
Midgut mitochondrial transhydrogenase in wandering stage larvae of the tobacco hornworm, Manduca sexta
Authors: Vandock Kurt P. , Smith Stan L. , Fioravanti Carmen F.
Published: October 2008

Midgut mitochondria from fifth larval instar Manduca sexta exhibited a transhydrogenase that catalyzes the following reversible reaction: NADPH + NAD+ ↔ NADP+ + NADH. The NADPH‐forming transhydrogenation occurred as a nonenergy‐ and energy‐linked activity. Energy for the latter was derived from the electron transport–dependent utilization of NADH or succinate, or from Mg++‐dependent ATP hydrolysis by ATPase. The NADH‐forming and all of the NADPH‐forming reactions appeared optimal at pH 7.5, were stable to prolonged dialysis, and displayed thermal lability. N,N′‐dicyclohexylcarbodiimide (DCCD) inhibited the NADPH → NAD+ and energy‐linked NADH → NADP+ transhydrogenations, but not the nonenergy‐linked NADH → NADP+ reaction. Oligomycin only inhibited the ATP‐dependent energy‐linked activity. The NADH‐forming, nonenergy‐linked NADPH‐forming, and the energy‐linked NADPH‐forming activities were membrane‐associated in M. sexta mitochondria. This is the first demonstration of the reversibility of the M. sexta mitochondrial transhydrogenase and, more importantly, the occurrence of nonenergy‐linked and energy‐linked NADH → NADP+ transhydrogenations. The potential relationship of the transhydrogenase to the mitochondrial, NADPH‐utilizing ecdysone‐20 monooxygenase of M. sexta is considered. Arch. Insect Biochem. Physiol. 69:118‐126, 2008. © 2008 Wiley‐Liss, Inc.
Plasma membrane permeabilization by 60‐ and 600‐ns electric pulses is determined by the absorbed dose
Authors: Ibey Bennett L. , Xiao Shu , Schoenbach Karl H. , Murphy Michael R. , Pakhomov Andrei G.
Published: October 2008

We explored how the effect of plasma membrane permeabilization by nanosecond‐duration electric pulses (nsEP) depends on the physical characteristics of exposure. The resting membrane resistance (Rm) and membrane potential (MP) were measured in cultured GH3 and CHO cells by conventional whole‐cell patch‐clamp technique. Intact cells were exposed to a single nsEP (60 or 600 ns duration, 0–22 kV/cm), followed by patch‐clamp measurements after a 2–3 min delay. Consistent with earlier findings, nsEP caused long‐lasting Rm decrease, accompanied by the loss of MP. The threshold for these effects was about 6 kV/cm for 60 ns pulses, and about 1 kV/cm for 600 ns pulses. Further analysis established that it was neither pulse duration nor the E‐field amplitude per se, but the absorbed dose that determined the magnitude of the biological effect. In other words, exposure to nsEP at either pulse duration caused equal effects if the absorbed doses were equal. The threshold absorbed dose to produce plasma membrane effects in either GH3 or CHO cells at either pulse duration was found to be at or below 10 mJ/g. Despite being determined by the dose, the nsEP effect clearly is not thermal, as the maximum heating at the threshold dose is less than 0.01 °C. The use of the absorbed dose as a universal exposure metric may help to compare and quantify nsEP sensitivity of different cell types and of cells in different physiological conditions. The absorbed dose may also prove to be a more useful metric than the incident E‐field in determining safety limits for high peak, low average power EMF emissions. Bioelectromagnetics 30:92–99, 2009. © 2008 Wiley‐Liss, Inc.
Umgelenkte Lamellen aus kohlefaserverstärktem Kunststoff für freistehende Spannglieder im Konstruktiven Ingenieurbau
Authors: Knippers Jan , Hwash Mohamed
Published: October 2008

Kohlenstofffaserverstärkter Kunststoff (CFK) besitzt eine Reihe von ausgezeichneten Eigenschaften mit weitreichenden Anwendungsmöglichkeiten im konstruktiven Ingenieurbau. So werden schon seit einigen Jahren CFK‐Lamellen für die Instandsetzung und nachträgliche Verstärkung von Bauteilen aus Stahlbeton eingesetzt.

Solche Lamellen könnten auch als freie Spannglieder, z. B. für extern vorgespannte Stahlbetonbrücken oder für unterspannte Decken im Hochbau, Verwendung finden. Die Empfindlichkeit von Kohlestofffaserverstärktem Kunststoff für Beanspruchungen durch Querpressungen macht jedoch die konstruktive Gestaltung der Endverankerung und der Umlenkung auf einem Sattel schwierig.

Für die Endverankerung liegen bereits Ansätze von verschiedenen Forschungseinrichtungen vor. In diesem Aufsatz werden die Ergebnisse von Versuchen zur Ermittlung des Einflusses einer Umlenkung auf die Bruchlast von CFK‐Lamellen veröffentlicht.
Brandschutz bei Tunneln
Authors: Haack Alfred
Published: October 2008

Die tragischen Tunnelbrandereignisse der letzten Jahre haben in Fachkreisen europa‐ und weltweit eine erhebliche Diskussion ausgelöst. In Deutschland haben sie für eine umfassende Überarbeitung der Sicherheitsrichtlinien für Straßen‐ und Eisenbahntunnel gesorgt, bei der Europäischen Kommission zur Ausarbeitung von Direktiven bezüglich der sicherheitstechnischen Mindestausstattung von Straßentunneln und auch von Eisenbahntunneln. Diese Entwicklung wurde ergänzt durch intensive Forschungsaktivitäten im nationalen und internationalen Bereich.

Die dabei gewonnenen Erkenntnisse fließen ein in Entwurf und Ausführung neuer Straßen‐ und Eisenbahntunnel. Dies gilt insbesondere auch für extrem lange Eisenbahntunnel, wie beispielsweise für den Brenner‐Basistunnel.
Brenner Basistunnel – Bau des Erkundungsstollens
Authors: Bergmeister Konrad
Published: October 2008

Der Brenner Basistunnel verläuft von der Umfahrung von Innsbruck bzw. vom Innsbrucker Bahnhof nach Franzensfeste mit einer Länge von 55 km. Mit der Umfahrung Innsbruck beträgt die Gesamtlänge 62, 8 km, womit er zum längsten Eisenbahntunnel der Welt wird. Zwei parallel verlaufende Tunnelröhren mit einem etwa 12 m tiefer liegenden Erkundungsstollen kennzeichnen diesen Basistunnel. Zur baubetrieblichen Risikominimierung des Basistunnels, insbesondere jene Anteile die mit Tunnelvortriebsmaschinen vorgetrieben werden sollen, sind systematische Erkundungen mittels eines Stollens von großer Bedeutung. Derzeit wird am 10 km langen Erkundungsstollen Aicha – Mauls mit einer Tunnelbohrmaschine gearbeitet. Der Ausbau erfolgt mit dünnwandigen Betontübbingen. Dort werden auch spezielle Monitoringpunkte angebracht. Die Querschnittsoptimierung der Tübbinge, die betontechnologischen Studien und die geeigneten Bereiche für das Monitoring werden dargestellt.
Der Malmö Citytunnel, Schweden – Tunnelbau in Skandinavien
Authors: Förder Martin , Abel Frank , Tirpitz Ernst‐Rainer
Published: October 2008

Der Citytunnel Malmö ist ein Eisenbahn‐Infrastrukturprojekt im Rahmen des Ausbaus des europäischen Hochgeschwindigkeitsnetzes, wobei neben der neuen Bahntrasse der ursprünglichen Sackbahnhof Malmö zu einem Durchgangsbahnhof erweitert wird und somit eine deutlich höhere Zug‐Taktzahl ermöglicht wird.

Für die Tübbingauskleidung wurde deutsches Know‐how mit den Erfahrungen aus europäischen Nachbarländern sinnfällig kombiniert. Zur Ausführung kam ein Uni‐Ring mit glatter Ringfuge und Führungsstangen in den Längsfugen, wobei es keine Zwischenlagen in den ebenen Ringfugen und keine Tübbingverschraubung in den Längsfugen außer am Schluss‐Stein gab.

Schon bei laufendem TBM‐Vortrieb wurden bereits die Querschläge zwischen den Tunnelröhren hergestellt. Bei einem Innendurchmesser der Tunnelröhren von 7.90 m war es für die zeitgleiche Ausführung wichtig, ein Öffnen der Tübbingringe ohne störende Aussteifung der erforderlichen Freiräume zu bewerkstelligen. Dies geschah mit Hilfe von Schubverzahnungselementen oberhalb und unterhalb der Öffnung.

Die Herstellung der Pfeiler und der Kopfbalken im Bahnhof Triangeln erfolgte mit selbstverdichtenden Beton (SVB). Die hohe Anzahl an Anforderungen machte die Entwicklung des SVBs schwierig und führte schließlich zu einer komplexen Beton‐Rezeptur.
Rotational tools for factor analytic models
Authors: Paatero Pentti , Hopke Philip K.
Published: October 2008

Rotational ambiguity is a major problem in the application of factor analysis to a variety of multivariate mixture resolution problems and particularly important in the analysis of environmental data. As part of the development of an implementation of positive matrix factorization for the U.S. Environmental Protection Agency to distribute in support of airborne particle source identification and apportionment, several tools have been developed to control the rotations and explore the extent of rotational solution space. This discussion of the nature of the rotational tools provides an understanding of these rotational tools as well as the basis for their incorporation into other implementations of least‐squares based solutions to the factor analysis problem. Several example algorithms are presented. Copyright © 2008 John Wiley & Sons, Ltd.
Dann machte ich mich allein auf den Weg, um den 11‐Uhr‐Zug zu erreichen. Sir Hans Adolf Krebs (1900–1981)
Authors: Roth Klaus
Published: October 2008

Nach der Entdeckung des Harnstoffzyklus im Jahr 1932 stieg die wissenschaftliche Reputation von Hans Adolf Krebs (1900–1981). Gleichzeitig zerfielen alle moralischen Werte einer demokratischen Gesellschaft durch den Aufstieg des Hitler‐Regimes und seinem Rassenwahn. Der Vergleich zwischen Labortagebüchern, persönlichen Briefwechseln, seiner Autobiographie und Erinnerungsstücken gibt Hinweise, wie es einem 32‐jährigen Wissenschaftler ergangen sein muss, der sich durch persönlichen und politischen Druck des Nazi‐Deutschlands gezwungen sah, sein Heimatland zu verlassen.
Warum Chilischoten scharf sind
Authors: Groß Michael
Published: October 2008

Früchte existieren, um gefressen zu werden. Doch warum enthalten viele von ihnen abschreckende bittere oder scharfe Geschmacksstoffe, oder gar Toxine? Die Anwort fanden Forscher in wilden Chili‐Pflanzen in Bolivien.
Superscharfe dreidimensionale Nanoskopie
Authors: Welter Kira
Published: October 2008

Ein neu entwickeltes “Nanoskop” ermöglicht Aufnahmen in bisher ungeahnter 3D Schärfe: Forscher erreichten eine Auflösung von unter 45 Nanometern in allen drei Raumrichtungen. Dank der neuen Technik konnten die Wissenschaftler erstmals einen scharfen 3D‐Blick in die Nanowelt der Zellen werfen, ohne diese dabei zu zerstören. Selbst solche Proteine, die tief im Inneren von Zellorganellen versteckt sind, lassen sich mit dem neuen Mikroskop optimal abbilden.
Changes in cancer incidence in teenagers and young adults (ages 13 to 24 years) in England 1979‒2003
Authors: Alston Robert D. , Geraci Marco , Eden Tim O. B. , Moran Anthony , Rowan Steve , Birch Jillian M.
Published: October 2008

BACKGROUND.

Cancer for teenagers and young adults represents a major source of morbidity and mortality. Trends in cancer incidence can provide pointers concerning how changes in the environment and in personal behavior affect cancer risks.

METHODS.

Data on 39,129 neoplasms in individuals ages 13 to 24 years who were diagnosed in England from 1979 to 2003 were analyzed. Variability in incidence by time period and differences in the time trends by age group, sex, and geographic region were analyzed using generalized linear models.

RESULTS.

Incidence rates of leukemias, lymphomas, central nervous system, bone, and germ cell tumors; melanoma; and carcinomas of the thyroid, ovary, cervix, and colon/rectum increased over time (all P < .01); whereas the incidence of carcinomas of the stomach and bladder decreased (both P < .01). These changes were consistent by age, sex, and region for most neoplasms. Melanoma incidence stabilized in southern England by 1993 but continued to increase in northern England (P = .001). The increase in non‐Hodgkin lymphoma was greater in individuals ages 20 to 24 year than in younger individuals, but the increase in Hodgkin lymphoma was confined to individuals ages 13 to 14 years.

CONCLUSIONS.

The changes in incidence rates may have been caused in part by environmental changes and in part by behavioral changes in young individuals. Some of these results can be used to inform public health campaigns, which can be constructed to encourage better lifestyle choices by young individuals. Cancer 2008. © 2008 American Cancer Society.
Outcome of adults with acute lymphocytic leukemia after second salvage therapy
Authors: O'Brien Susan , Thomas Deborah , Ravandi Farhad , Faderl Stefan , Cortes Jorge , Borthakur Gautum , Pierce Sherry , Garcia‐Manero Guillermo , Kantarjian Hagop M.
Published: October 2008

BACKGROUND.

The outcome of adults with acute lymphocytic leukemia (ALL) who undergo second salvage therapy has been characterized poorly. This is important with regard to investigational approaches aimed at helping this subset of patients. The objectives of the current study were to predict outcomes and determine the prognostic factors associated with second salvage therapy in patients with ALL.

METHODS.

In this study, 288 patients were analyzed who received second salvage therapy for ALL at the authors' institution.

RESULTS.

Overall, 53 patients (18%) achieved a complete response (CR). The median remission duration was 7 months and the median survival was 3 months. In multivariate analysis, prognostic factors that were associated independently with achieving CR were duration of first CR and platelet count. Patients with a first CR <36 months and platelet counts <50 × 109/L had an expected CR rate of 7%. In multivariate analysis, prognostic factors that were associated independently with survival were duration of first CR, percentage bone marrow blasts, platelet count, and albumin level. The expected 12‐month survival rates for patients with 0 or 1, 2, 3, or 4 adverse factors were 33%, 14%, 8%, and 0%, respectively. A repeat multivariate analysis using landmark assessment at 6 weeks selected achievement of CR as adding significantly to the survival benefit (P= .0001; hazard ratio, 0.51). Only 22 patients (8%) were able to undergo allogeneic stem cell transplantation as second salvage therapy, and their 1‐year survival rate was 18%.

CONCLUSIONS.

The outcome of adults with ALL undergoing second salvage therapy is poor. Novel effective therapies against ALL are needed in this subset of patients. Cancer 2008. © 2008 American Cancer Society.
Comparative analysis of serotonin receptor (HTR1A/HTR1B families) and transporter (slc6a4a/b) gene expression in the zebrafish brain
Authors: Norton William H.J. , Folchert Anja , Bally‐Cuif Laure
Published: October 2008

In this study we analyze 5‐hydroxytryptamine [5‐HT]; serotonin) signaling in zebrafish, an increasingly popular vertebrate disease model. We compare and contrast expression of the 5‐HT transporter genesslc6a4aandslc6a4b, which identify 5‐HT‐producing neurons and three novel 5‐HT receptors,htr1aa,htr1ab, andhtr1bd.slc6a4aandslc6a4bare expressed in the raphe nuclei, retina, medulla oblongata, paraventricular organ, pretectal diencephalic complex, and caudal zone of the periventricular hypothalamus, in line with the expression profiles of homologues from other vertebrates. Our analysis of serotonin transporter (SERT)‐encoding genes also identifies parallel genetic pathways used to build the 5‐HT system in zebrafish. In cells in which 5‐HT is synthesized bytph1,slc6a4bis used for re‐uptake, whereastph2‐positive cells utilizeslc6a4a. The receptorshtr1aa,htr1ab, andhtr1bdalso show widespread expression in both the larval and adult brain. Receptor expression is seen in the superior raphe nucleus, retina, ventral telencephalon, optic tectum, thalamus, posterior tuberculum, cerebellum, hypothalamus, and reticular formation, thus implicating 5‐HT signaling in several neural circuits. We also examine larval brains double‐labeled with 5‐HTergic and dopaminergic pathway‐specific antibodies, to uncover the identity of some 5‐HTergic target neurons. Furthermore, comparison of the expression of transporter and receptor genes also allows us to map sites of autoreceptor activity within the brain. We detect autoreceptor activity in the pretectal diencephalic cluster (htr1aa‐,htr1ab‐,htr1bd‐, andslc6a4a‐positive), superior raphe nucleus (htr1aa‐,htr1ab‐, andslc6a4a‐positive), paraventricular organ (htr1aa‐,htr1ab‐,htr1bd‐, andslc6a4b‐positive), and the caudal zone of the periventricular hypothalamus (htr1ab‐ andslc6a4b‐positive). J. Comp. Neurol. 511:521–542, 2008. © 2008 Wiley‐Liss, Inc.
Visualizing mechanosensory endings of TrkC‐expressing neurons in HS3ST‐2‐hPLAP mice
Authors: Hasegawa Hiroshi , Wang Fan
Published: October 2008

Somatosensory neurons are classified into three main types according to their modalities: nociceptive, thermal, and mechanosensory. Within each modality group, neurons can be further divided into morphologically and functionally distinct subclasses. Here we show that heparan sulfate D‐glucosaminyl 3‐O‐sulfotransferase 2 (HS3ST‐2) is a marker for specific subsets of TrkC‐expressing cutaneous low‐threshold mechanosensory and proprioceptive mechanosensory neurons. Two‐color in situ analysis revealed that almost all HS3ST‐2 signals colocalized with TrkC but not with TrkA or TrkB mRNA. To visualize the morphological subtypes of HS3ST‐2/TrkC‐expressing neurons, we generated a HS3ST‐2‐hPLAP knock‐in mouse line, in which HS3ST‐2‐expressing neurons and their projections are labeled by human placental alkaline phosphatase (hPLAP). AP staining in these mice demonstrated that sensory endings of muscle spindles and Golgi tendon organs as well as the cutaneous mechanosensory Merkel and longitudinal lanceolate endings in the whiskers are strongly positive for hPLAP activity. In contrast, no nociceptive endings are labeled. In the glabrous and hairy skin, rare Merkel endings and transverse lanceolate endings are weakly stained. During development, each type of nerve endings forms at different time point. Muscle innervations differentiate first, followed by formation of cutaneous sensory endings. Our results revealed the subtype identities of TrkC‐positive mechanosensory neurons and demonstrated the usefulness of HS3ST‐2 as a genetic marker for these subclasses of neurons. J. Comp. Neurol. 511:543–556, 2008. © 2008 Wiley‐Liss, Inc.
Photothermal CVD of Carbon Thin Films using CH2I2 as the Precursor
Authors: Rashid Abdul , Landström Lars , Ottosson Mikael , Piglmayer Klaus
Published: October 2008

Thin carbon films are deposited via CVD from the precursor methylene iodide (CH2I2) using two different activation sources; a broadband IR lamp and a thermal plate. Large differences in deposition rates are observed when comparing the two sources of activation. The characteristics of the deposition kinetics of the highly sensitive system are also investigated by employing a split, symmetric reactor, and by using a qualitative model. Raman spectroscopy (RS) is used for microstructural characterization of the films. The lamp technique allows a simple and low‐cost experimental setup, for deposition of disordered carbon thin films at relatively low temperatures and high rates.
Density Investigation by X‐ray Reflectivity for Thin Films Synthesized Using Atmospheric CVD
Authors: Kishimoto Shinichi , Hashiguchi Tomoaki , Ohshio Shigeo , Saitoh Hidetoshi
Published: October 2008

The density of hafnia and titania films is investigated by an X‐ray reflectivity (XRR) analysis using an X‐ray diffractometer equipped with a relatively low power X‐ray source. Several films are prepared using a CVD technique operated under atmospheric pressure. The XRR profile of the hafnia films is obtained, and fitted with the assumption of the existence of an HfSiO intermediate layer on the Si substrate with a SiO2 layer. The density of the hafnia films is lower than that of the bulk crystal. On the other hand, the XRR profile of the titania films on the glass substrate can be fitted using a seven‐lamella model. The film density of titania is also lower than that of the bulk crystal. XRR analysis may become a powerful weapon to determine not only the structure model but also the crystallinity of each layer.
Synthesis, Characterisation, Complexation and Electrochemistry of Linear Tridentate FcE(CH2)3E′(CH2)3EFc (E, E′ = Se or Te) Ligands: X‐ray Crystal Structures of FcSe(CH2)3Se(CH2)3SeFc and [PtCl{FcSe(CH2)3Se(CH2)3SeFc}]PF6 {Fc = [Fe(η5‐C5H5)(η5‐C5H4)]}
Authors: Jing Su , Morley Christopher P. , Webster Christopher A. , Di Vaira Massimo
Published: October 2008

A series of linear tridentate ligands, FcE(CH2)3E′(CH2)3EFc (E, E′ = Se or Te), was synthesised. Their chloropalladium(II) and chloroplatinum(II) complexes were also prepared. The new compounds were characterised by a range of spectroscopic and analytical techniques, including multinuclear NMR spectrometry and X‐ray crystallography. In an electrochemistry study of the complexes no communication between the ferrocenyl centres was observed, regardless of the through‐bond Fe···Fe distance.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Design of Neutral Metallomesogens from 5,5‐Dimethyldipyrromethane: Metal Ion Mediated Control of Folding and Hairpin Structures
Authors: Ames Kelly A. , Collinson Simon R. , Blake Alexander J. , Wilson Claire , Love Jason B. , Bruce Duncan W. , Donnio Bertrand , Guillon Daniel , Schröder Martin
Published: October 2008

New ligands derived from 5,5‐dimethyldipyrromethane and their corresponding neutral complexes with ZnII and PdII are described. The ligands incorporate either a hexacatenar [H2(1n), n = 1, 10, 12, 14 and 16], tetracatenar [H2(2n), n = 1 and 16] or an extended dicatenar structure [H2(3n), n = 1and 16]. Single‐crystal X‐ray structure determinations of [Zn2(11)2] and [Zn2(31)2] confirm a distorted tetrahedral geometry at ZnII to afford double‐stranded helical structures, while the PdII species [Pd(31)] shows a distorted square‐planar geometry with the ligand adopting an alternative hairpin conformation. The metal‐free hexacatenar ligands H2(1n) (n = 10, 12, 14, 16) and the corresponding complexes [Zn2(116)2] and [Pd(1n)] (n = 12, 14, 16) are not mesomorphic. However, the tetracatenar complex [Zn2(216)2] generates a smectic mesophase, as confirmed by X‐ray diffraction, while [Pd(216)] and the metal‐free ligand H2(216) show no mesomorphic behaviour. Two of the extended dicatenar compounds, H2(316) and [Zn2(316)2] are non‐mesomorphic, while [Pd(316)] displays a smectic A phase.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis of Spherical Down‐ and Up‐Conversion NaYF4‐Based Nanophosphors with Tunable Size in Ethylene Glycol without Surfactants or Capping Additives (Eur. J. Inorg. Chem. 29/2008)
Authors: Nuñez Nuria O. , Míguez Hernán , Quintanilla Marta , Cantelar Eugenio , Cussó Fernando , Ocaña Manuel
Published: October 2008

The cover picture shows spherical nanoparticles consisting of NaYF4 co‐doped with Er3+/Yb3+, which have been synthesised through a procedure simpler and less harmful than other methods previously reported, since it does not require the use of surfactant or capping additives. As illustrated in the picture, these nanoparticles emit visible light in the green and red regions when irradiated with infrared (980 nm) radiation. This property, known as up‐conversion fluorescence, confers on the nanophosphors potential applications in several fields, including biotechnology. Details are discussed in the article by M. Ocaña et al. on p. 4517 ff.