bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Nanocrystalline Hydroxyapatite Nanorods via Hydrothermal Conditions
Authors: Manafi S. , Rahimipour M. R.
Published: May 2011

The effect of Ca(NO3)2·4H2O and (NH4)2HPO4 primary solutions as the starting materials in the synthesis of a calcium phosphate phase was examined. Therefore, wet chemical reactions were investigated in solution at different temperatures by hydrothermal conditions aimed at hydroxyapatite (Ca10(PO4)6(OH)2, HAp) synthesis. The powders were investigated by XRD, SEM, FE‐TEM, HRTEM, EDAX, SAED, and FTIR. It is found that the HAp have diameters of 25–50 nm and lengths of 120�30 nm with different morphologies. As a matter of fact, the hydrothermal method guarantees the production of HAp for different applications.
Modulated Synthesis of Zr‐Based Metal–Organic Frameworks: From Nano to Single Crystals
Authors: Schaate Andreas , Roy Pascal , Godt Adelheid , Lippke Jann , Waltz Florian , Wiebcke Michael , Behrens Peter
Published: May 2011

We present an investigation on the influence of benzoic acid, acetic acid, and water on the syntheses of the Zr‐based metal–organic frameworks Zr–bdc (UiO‐66), Zr–bdc–NH2 (UiO‐66–NH2), Zr–bpdc (UiO‐67), and Zr–tpdc–NH2 (UiO‐68–NH2) (H2bdc: terephthalic acid, H2bpdc: biphenyl‐4,4′‐dicarboxylic acid, H2tpdc: terphenyl‐4,4′′‐dicarboxylic acid). By varying the amount of benzoic or acetic acid, the synthesis of Zr–bdc can be modulated. With increasing concentration of the modulator, the products change from intergrown to individual crystals, the size of which can be tuned. Addition of benzoic acid also affects the size and morphology of Zr–bpdc and, additionally, makes the synthesis of Zr–bpdc highly reproducible. The control of crystal and particle size is proven by powder XRD, SEM and dynamic light scattering (DLS) measurements. Thermogravimetric analysis (TGA) and Ar sorption experiments show that the materials from modulated syntheses can be activated and that they exhibit high specific surface areas. Water proved to be essential for the formation of well‐ordered Zr–bdc–NH2. Zr–tpdc–NH2, a material with a structure analogous to that of Zr–bdc and Zr–bpdc, but with the longer, functionalized linker 2′‐amino‐1,1′:4′,1′′‐terphenyl‐4,4′′‐dicarboxylic acid, was obtained as single crystals. This allowed the first single‐crystal structural analysis of a Zr‐based metal–organic framework.
Rodlike Macromolecules through Spatial Overlapping of Thiophene Dendrons
Authors: Kimura Mutsumi , Kitao Akiko , Fukawa Tadashi , Shirai Hirofusa
Published: May 2011

Two novel dendritic macromonomers 7 and 8 functionalized with electroactive conjugated thiophene oligomers were synthesized by stepwise cross‐coupling reactions and the introduction of a vinyl group at the focal point. Both macromonomers were polymerized into dendronized polymers 9 and 10 by using a radical polymerization method. The photophysical and redox behaviors of dendronized polymers 9 and 10 are significantly different from those of the corresponding macromonomers. This difference may result from the spatial overlapping of thiophene dendrons through π–π interactions when the dendrons are connected to a polymer backbone. The dendronized polymers can organize into large‐area two‐dimensional sheets with a thickness of 4.8 nm. Polymer 9, which has all‐dendritic thiophene side chains, exhibited enhanced conductivity by partial doping with iodine or nitrosonium tetrafluoroborate (NOBF4). The novel amphiphilic dendronized polymer 15 was synthesized by the atom‐transfer radical polymerization of macromonomer 7 from a poly(ethylene glycol) (PEG) macroinitiator and was found to have a self‐organized structure in water.
On the Role of Intermolecular Interactions on Structural and Spin‐Crossover Properties of 2D Coordination Networks [Fe(bbtr)3]A2 (bbtr=1,4‐bis(1,2,3‐triazol‐1‐yl)butane; A=ClO4−, BF4−)
Authors: Kusz Joachim , Bronisz Robert , Zubko Maciej , Bednarek Gabriela
Published: May 2011

A series of complexes [M(bbtr)3]A2 (M=FeII, ZnII; bbtr=1,4‐bis(1,2,3‐triazol‐1‐yl)butane; A=ClO4−, BF4−) and [FexZn1−x(bbtr)3](ClO4)2 (0<x<1) dilute systems was synthesized and characterized. Earlier studies on [Fe(bbtr)3](ClO4)2 (1⋅ClO4), which crystallizes in space group P$\bar 3$, revealed an abrupt spin transition with ${T_{1/2}^ \downarrow }$≈101 K and ${T_{1/2}^ \uparrow }$≈109 K. Variable‐temperature measurements of the lattice parameters and change in Bragg peaks profiles of 1⋅ClO4 showed a structural phase transition at 125 K leading to space group P$\bar 1$. Single‐crystal X‐ray diffraction studies allowed structures of the quenched high‐spin phase and then a low‐symmetry low‐spin phase of 1⋅ClO4 to be determined. We established that tetrafluoroborate analogue 1⋅BF4 remains in the high‐spin form in the temperature range 5–300 K. Contrary to 1⋅ClO4, structural investigations did not reveal the presence of a structural phase transition in 1⋅BF4. Analogous to 1⋅ClO4, [Zn(bbtr)3](ClO4)2 (2⋅ClO4) undergoes a structural transition at 151 K, whereas at low‐temperature [Zn(bbtr)3](BF4)2 (2⋅BF4) remains in space group P$\bar 3$. The structural phase transitions in both perchlorates are accompanied by similar reorganization of the intermolecular contacts, which leads to a shift of 2D layers. In effect, compression of the unit cell takes place, favouring the appearance of the spin transition in 1⋅ClO4 in relation to 1⋅BF4. The metal ion determines the temperature of the structural phase transition in 1⋅ClO4 and 2⋅ClO4. This property was exploited to separate the non‐magnetic structural transformation and spin transition in 1⋅ClO4. The spin and structural transitions in the [FexZn1−x(bbtr)3](ClO4)2 systems take place at different temperatures, and the temperature difference between them increases with increasing zinc(II) content. This means that structural phase transition is necessary for appearance of the spin transition, but this transformation does not trigger directly the spin transition in 1⋅ClO4.
Solid suspension in stirred tanks: UVP measurements and CFD simulations
Authors: Sardeshpande Madhavi V. , Juvekar V. A. , Ranade Vivek V.
Published: May 2011

Suspension of solids in stirred reactor is widely used for catalytic reactions, dissolution, etc. Quality of solid suspension is an important parameter required for the reliable design, optimum performance, and scale up of the system. Quality of suspension depends on local characteristics of solid velocity and hold up profiles. The present work was focused on investigating quality of solid suspension using ultrasound velocity profiler (UVP) measurements and CFD simulations. The slip velocity measurements carried out with UVP were used to evaluate different drag correlations used in CFD simulations. Results discussed in this work would be useful for extending the applications of CFD models for simulating large stirred slurry reactors.
Cost‐effective queue schemes for reducing head‐of‐line blocking in fat‐trees
Authors: Escudero‐Sahuquillo J. , Garcia P. J. , Quiles F. J. , Flich J. , Duato J.
Published: May 2011

The fat‐tree is one of the most common topologies among the interconnection networks of the systems currently used for high‐performance parallel computing. Among other advantages, fat‐trees allow the use of simple but very efficient routing schemes. One of them is a deterministic routing algorithm that has been recently proposed, offering a similar (or better) performance than adaptive routing while reducing complexity and guaranteeing in‐order packet delivery. However, as other deterministic routing proposals, this deterministic routing algorithm cannot react when high traffic loads or hot‐spot traffic scenarios produce severe contention for the use of network resources, leading to the appearance of Head‐of‐Line (HoL) blocking, which spoils the network performance. In that sense, we describe in this paper two simple, cost‐effective strategies for dealing with the HoL‐blocking problem that may appear in fat‐trees with the aforementioned deterministic routing algorithm. From the results presented in the paper, we conclude that, in the mentioned environment, these proposals considerably reduce HoL‐blocking without significantly increasing switch complexity and the required silicon area. Copyright © 2011 John Wiley & Sons, Ltd.
Static and Dynamic Stereochemistry of Chiral Ln DOTA Analogues
Authors: Di Bari Lorenzo , Salvadori Piero
Published: May 2011

Ln DOTA derivatives (DOTA=1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid) are known to undergo relevant stereoisomeric equilibria in solution, which greatly modulate their chemical as well as their magnetic and optical properties. The subject is reviewed in terms of classical stereochemical description, with reference to conformational enthalpies. Yb is taken as the reference element because of its unique spectroscopic properties, namely, a small contact contribution to the paramagnetic shift and an intense near‐infrared electronic circular dichroism, endowed with an easily recognizable fine structure.
Chromosome remodeling and differentiation of tetraploid embryos during preimplantation development
Authors: Park Mi‐Ryung , Lee Ah‐Reum , Bui Hong‐Thuy , Park Chankyu , Park Keun‐Kyu , Cho Ssang‐Goo , Song Hyuk , Kim Jae‐Hwan , Van Thuan Nguyen , Kim Jin‐Hoi
Published: May 2011

Although it is known that the tetraploid embryo contributes only to the placenta, the question of why tetraploid embryos differentiate into placenta remains unclear. To study the effect of electrofusion on the development of mouse tetraploid oocytes, mouse two‐cell embryos were fused and cultured in vitro in Chatot‐Ziomek‐Bavister medium. After electrofusion, two chromosome sets from the tetraploid blastomere were individually duplicated before nuclear fusion. At 8–10 hr after electrofusion, each chromosome set was condensing and the nuclear membrane was breaking down. Around 12–14 hr after electrofusion, the two chromosome sets had combined together and had reached the second mitotic metaphase, at this point with 8n sets of chromosomes. Interestingly, we discovered that expression of OCT4, an inner cell mass cells biomarker, is lost by the tetraploid expanded blastocysts, but that CDX2, a trophectoderm cells biomarker, is strongly expressed at this stage. This observation provides evidence clarifying why tetraploid embryos contribute only to trophectoderm. Developmental Dynamics 240:1660–1669, 2011. © 2011 Wiley‐Liss, Inc.
New Binding Modes of 1‐Acetyl‐ and 1‐Benzoyl‐5‐hydroxypyrazolines – Synthesis and Characterization of O,O′‐Pyrazoline‐ and N,O‐Pyrazoline‐Zinc Complexes
Authors: Someya Chika I. , Inoue Shigeyoshi , Irran Elisabeth , Krackl Sebastian , Enthaler Stephan
Published: May 2011

The 1‐acetyl‐ and 1‐benzoyl‐5‐hydroxypyrazolines 1a [3,5‐CF3, 1‐C(=O)CH3], 1b [3,5‐CH3, 1‐C(=O)CH3] and 1c [3,5‐CF3, 1‐C(=O)C6H5] have been synthesized in good yields and characterized by X‐ray crystallography. The 1‐acetyl‐ and 1‐benzoyl‐5‐hydroxypyrazoline ligands were treated with dimethylzinc in a 1:1 molar ratio to form complexes 8 with a RO–Zn–Me motif. These complexes are accessible by simple Brønsted acid–base reactions generating methane as a side product. Characterization of complexes 8a and 8c by X‐ray crystallography revealed a dimeric structure in the solid state. The two subunits generate a Zn2O2 square. The acetyl and benzoyl functionality of the ligands coordinate to the metal to span a six‐membered ring. Moreover, the coordination mode of the ligand can be easily influenced by the addition of base. Here, N,N,N′,N′‐tetramethylethylenediamine (tmeda) was applied to remove the acidic proton in the 4‐position of the ligand and to cleave the hemiaminal functional group. The tmeda‐H+ transfers the proton to the methyl group connected to the zinc and facilitates the removal of methane; the free tmeda coordinates to the zinc in a bidentate fashion. The positive charge at the zinc and the negative charge in the ligand recombine to form complex 9. Surprisingly, the characterization of complex 9c by X‐ray crystallography showed the formation of the first zinc‐based seven‐membered system with covalent bonding (N1,O6‐coordination) in the solid state, whereas for other metals O6,N2,O7‐coordination has been reported.
Retention of Symmetry Versus Desymmetrization for Bicyclo[2.2.2]octenes in the Presence of a Bridgehead Amide Group
Authors: Hren Jure , Perdih Franc , Polanc Slovenko , Kočevar Marijan
Published: May 2011

An efficient, microwave‐assisted and ionic‐liquid‐catalyzed esterification of bicyclo[2.2.2]oct‐7‐ene‐2,3,5,6‐tetracarboxylic acid dianhydride derivatives into the corresponding tetraesters is presented. The latter were subjected to a base‐catalyzed isomerization reaction, which proceeded with the retention of symmetry.
Incorporation of guanosine gels into sieving matrices for length‐ and sequence‐based separation of DNA in capillary electrophoresis
Authors: Dong Yingying , McGown Linda B.
Published: May 2011

Sieving gels are used in capillary gel electrophoresis to resolve DNA strands of different lengths. For complex samples, however, such as those encountered in metagenomic analysis of microbial communities or biofilms, length‐based separation may mask the true genetic diversity of the community since different organisms may contribute same‐length DNA with different sequences. There is a need, therefore, for DNA separations based on both the length and sequence. Previous work has demonstrated the ability of guanosine gels (G‐gels) to separate four single‐stranded DNA 76‐mers that differ by only a few A/G base substitutions. The goal of the present work is to determine whether G‐gels could be combined with commercial sieving gels in order to simultaneously separate DNA based on both length and sequence. The results are given for the four 76‐mers and for a standard dsDNA ladder. Commercial sieving gels were used alone and in combination with G‐gels. For the 76‐mers, the combined medium was less efficient than the G‐gel alone but was able to achieve partial resolution. The combined medium was at least as effective as the sieving gel alone at resolving the denatured DNA ladder and showed indications of sequence‐based resolution as well, as supported by MALDI‐MS. The results show that the combined sieving gel/G‐gel medium retains the selectivity of the individual media, providing a promising approach to simultaneous length‐ and sequence‐based DNA separation for metagenomic analysis of complex systems.
Ion‐permeable membrane for on‐chip preconcentration and separation of cancer marker proteins
Authors: Nge Pamela N. , Yang Weichun , Pagaduan Jayson V. , Woolley Adam T.
Published: May 2011

Cancer marker proteins have been electrophoretically concentrated and then separated in a microfluidic device. On‐chip preconcentration was achieved using an ion‐permeable membrane, consisting of acrylamide, N,N′‐methylene‐bisacrylamide and 2‐(acrylamido)‐2‐methylpropanesulfonate. This negatively charged membrane was photopolymerized in the microdevice near the injection intersection. Anionic proteins were excluded from the porous membrane based on both size and charge, which concentrated target components in the injection intersection prior to separation by microchip capillary electrophoresis (μ‐CE). Bovine serum albumin was used in the initial characterization of the system and showed a 40‐fold enrichment in the μ‐CE peak with 4 min of preconcentration. Adjustment of buffer pH enabled baseline resolution of two cancer biomarkers, α‐fetoprotein (AFP) and heat shock protein 90 (HSP90), while fine control over preconcentration time limited peak broadening. Our optimized preconcentration and μ‐CE approach was applied to AFP and HSP90, where enrichment factors of >10‐fold were achieved with just 1 min of preconcentration. Overall, the process was simple and rapid, providing a useful tool for improving detection in microscale systems.
Regulation of cigarette smoke‐mediated mucin expression by hypoxia‐inducible factor‐1α via epidermal growth factor receptor‐mediated signaling pathways
Authors: Yu Hongmei , Li Qi , Kolosov Victor P. , Perelman Juliy M. , Zhou Xiangdong
Published: May 2011

Cigarette smoking is strongly implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). Mucus hypersecretion is the key manifestation in patients with COPD and mucin 5AC (MUC5AC) is a major component of airway mucus. Hypoxia inducible factor‐1 (HIF‐1) is a transcriptional factor which can be stimulated to bind to the MUC5AC promoter and induce MUC5AC promoter activation. Previous studies have reported that activation of HIF‐1α pathways by cigarette smoke contributes to the development of COPD. We hypothesize that cigarette smoke up‐regulates HIF‐1α production and HIF‐1 activity through epidermal growth factor receptor (EGFR)‐activated signal cascades pathways, leading to mucin production in human airway epithelial cells (16HBE). We show that cigarette smoke increases HIF‐1α production, HIF‐1 activity and MUC5AC expression. These effects are prevented by small interfering RNA (siRNA) for HIF‐1α, indicating that cigarette smoke‐induced mucin production is HIF‐1α‐dependent. Cigarette smoke activates extracellular signal‐regulated kinase 1/2 (ERK1/2) and phosphatidylinositol 3‐kinase (PI3K) signal pathways, both of which are inhibited by gefitinib (an inhibitor of EGFR), suggesting that cigarette smoke‐activated signal pathways are mediated by EGFR in 16HBE cells. Furthermore, pretreatment with gefitinib and the pharmacological inhibitors of PI3K (LY294002) and ERK1/2 (PD98059) prevented cigarette smoke‐mediated Akt and ERK1/2 phosphorylation responses, HIF‐1α production, HIF‐1 activity and MUC5AC expression. These observations demonstrate an important role for EGFR‐mediated signaling pathways in regulating cigarette smoke‐induced HIF‐1 activation and MUC5AC expression. Our results suggest that cigarette smoke activates EGFR‐mediated signaling pathways, leading to HIF‐1α production and HIF‐1 activation, resulting in mucin expression in human airway epithelial cells. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis of 2,3‐dihydro‐6H‐1‐oxa‐3a‐aza‐phenalene and its benzo/hetero‐fused analog
Authors: Mizar Pushpak , Hormi Mecadon , Rajbangshi Mantu , Myrboh Bekington
Published: May 2011

A simple and efficient method for the synthesis of highly substituted benzo‐ and hetero‐fused analog of 2, 3‐dihydro‐6H‐oxa‐3a‐aza‐phenalene was developed using 2H‐1, 4‐benzoxazine and α‐oxoketene dithio‐acetals. J. Heterocyclic Chem., (2011).
DOES FOREIGN AID REDUCE POVERTY?
Authors: Alvi Eskander , Senbeta Aberra
Published: May 2011

This paper examines the effect of foreign aid on poverty. The impact of aid on poverty is assessed using dynamic panel estimation techniques, which enable us to control for time‐invariant country‐specific effects and endogeneity of aid. The results suggest that aid has a significant poverty‐reducing effect even after controlling for average income. Specifically, foreign aid is associated with a decline in poverty as measured by the poverty rate, poverty gap index and squared poverty gap index. We also find that the composition of aid matters—multilateral aid and grants do better in reducing poverty than bilateral aid and loans. Copyright © 2011 John Wiley & Sons, Ltd.
A new specialization in astrocytes: Glutamate‐ and ammonia‐induced nuclear size changes
Authors: Yang Chun Zhang , Li Hui Li , Zhou Ye , Chai Rui Chao , Zhao Rui , Dong Yan , Xu Zhen Yu , Lau Lok Ting , Yingge Zhang , Teng Junlin , Chen Jianguo , Yu Albert Cheung Hoi
Published: May 2011

We observed nuclear swelling in glutamate (Glu)‐treated astrocytes that was concomitant with but independent of astrocytic cell swelling. We confirmed Glu‐induced nuclear swelling with nuclei isolated from astrocytes. Ammonia is metabolically related to Glu and could induce a nuclear swelling in intact astrocytes but shrinkage in isolated nuclei. Other compounds such as glutamine, aspartate, taurine, glycine, and ATP did not cause any nuclear swelling in isolated nuclei of astrocytes. Surprisingly, Glu and ammonia did not induce nuclear swelling in microglia, C6, HEK 293, or Hep G2 cell lines in cultures and their isolated nuclei. The Glu‐ and ammonia‐induced nuclear size changes appear to be a specific response of astrocytes to these two closely related metabolic compounds. © 2011 Wiley‐Liss, Inc.
Phenol‐containing organic substances stimulate phenylpropanoid metabolism in Zea mays
Authors: Ertani Andrea , Schiavon Michela , Altissimo Adriano , Franceschi Clizia , Nardi Serenella
Published: May 2011

Intensive land use may affect soil properties (e.g., decreased soil organic matter [SOM] content) and, consequently, reduce crop yields considerably. One way of counteracting the loss of SOM and stimulating plant productivity could be the use of organic residues from agro‐industrial processes as bioactive products. The present study was focused on the possible effects of phenol‐containing organic substances derived from agro‐industrial by‐products on maize (Zea mays L.) metabolism in a pot experiment. Plants were grown for 12 d in a nutrient solution in the absence (control) or in the presence of either a cellulosolitic dry apple hydrolyzate (AP) or a dry blueberry cool extract (BB) applied at two rates (0.1 and 1 mL L–1). Both products increased root and leaf biomass and led to higher concentrations of macronutrients in the plant tissue. AP and BB also had a positive impact on nitrogen (N) metabolism stimulating the activity and gene expression of phenylalanine ammonia‐lyase, a key enzyme of the phenylpropanoid pathway. Furthermore, both products increased leaf concentrations of phenols (+ 28% and 49% for AP and BB, respectively) and flavonoids (+ 22% and 25% for AP and BB, respectively). From our results it can be assumed that residues from agro‐industry may be successfully used as bioactive products in agriculture to increase plant yield and resistance to stress conditions.
Peritoneal carcinomatosis of colon cancer origin: Highest incidence in women and in patients with right‐sided tumors
Authors: Sjo Ole Helmer , Berg Marianne , Merok Marianne Arstad , Kolberg Matthias , Svindland Aud , Lothe Ragnhild A. , Nesbakken Arild
Published: May 2011

Background and Objectives

: The aim of the study was to evaluate the incidence of peritoneal carcinomatosis (PC) in a prospectively recorded series of colon cancer patients from a defined cohort and to compare clinicopathological characteristics, survival, and TP53 mutation status in primary tumors from patients with and without PC.

Methods

: Clinical data from all colon cancer patients admitted in 1993–2006 were registered prospectively (n = 1,124). In a subset of PC patients, DNA was retrieved from tumor tissue and TP53 mutations analyzed and compared to the mutation status in a historical series.

Results

: In the prospective series 10% of female and 7% of male patients had PC (P = 0.05). The PC patients were younger than those without PC (median 4 years, P = 0.002). The incidence of PC was 10.3% and 6.2% (P = 0.03) in patients with primary tumors in the right and left colon, respectively. TP53 was mutated in 57% of the PC patients as compared to 41% in the series of patients without PC (P = 0.05).

Conclusions

: The incidence of PC was higher in right‐sided colon cancer and among women. PC patients were younger than non‐PC patients, and PC was independently associated with TP53 mutation in the primary tumor. J. Surg. Oncol. © 2011 Wiley Periodicals, Inc.
Magnetic mixed hemimicelles solid‐phase extraction of xanthohumol in beer coupled with high‐performance liquid chromatography determination
Authors: Ding Jie , Zhao Qi , Sun Lei , Ding Lan , Ren Nanqi
Published: May 2011

In this study, silica‐coated magnetic nanoparticles (Fe3O4/SiO2 NPs) modified by cetyltrimethylammonium bromide (CTAB) were synthesized. They were successfully applied for extraction of xanthohumol in beer based on magnetic mixed hemimicelles solid‐phase extraction (MMHSPE) coupled with high‐performance liquid chromatography – ultraviolet determination. The main factors influencing the extraction efficiency including the surfactant amount, the beer pH, the extraction time, the desorption condition and the maximum extraction beer volume were optimized. Under the optimized conditions, a concentration factor of 60 was achieved by extracting 120 mL beer sample using MMHSPE and the detection limit of xanthohumol is 0.0006 mg/L. The proposed method was successfully applied for determination of xanthohumol in various beer samples with the xanthohumol contents in the range of 0.031–0.567 mg/L. The satisfactory recoveries (90–103%) were obtained in analyzing spiked beer samples.
Sufficiency of horseshoe crab eggs for red knots during spring migration stopover in Delaware Bay USA
Authors: Karpanty Sarah M. , Cohen Jonathan , Fraser James D. , Berkson Jim
Published: May 2011

Horseshoe crab (Limulus polyphemus) eggs are a dietary staple of the red knot (Calidris canutus) during its spring stopover on the Delaware Bay. Numbers of knots stopping in Delaware Bay declined in the 1990s concurrent with a decline in horseshoe crabs, leading to the hypothesis that reduced horseshoe crab egg abundance limited the red knot population. Management efforts, including a seasonal harvest moratorium in the Delaware Bay, have been instituted to restore crab populations to levels of sustainable use by multiple users, including migratory birds. Our objective was to evaluate the sufficiency of horseshoe crab eggs in Delaware Bay in May–June 2004 and 2005 for knots to refuel for their migratory flight to the Arctic breeding grounds. We examined egg counts to determine if there were fewer high egg‐density sites later than earlier in the day and season, as migrating birds might deplete this resource. We studied foraging rates at red knot locations to determine if foraging probes increased with time of day and season as birds depleted surface eggs by pecking, then began probing for subsurface eggs. Finally, we experimentally tested whether red knots and their competitors depleted horseshoe crab eggs. Crab egg numbers at knot foraging sites did not decline throughout the day or season in 2004. In both years, we found no evidence that knots switched from pecking to probing with increases in time since sunrise or start of the stopover. Egg numbers were similar in exclosed and accessible plots on crab nesting depressions and in areas of open intertidal zone, but were significantly lower in accessible than in exclosed plots in the wrack line. Our results indicate that horseshoe crab eggs in Delaware Bay were sufficient to support the refueling of the present‐day stopover population of red knots. If an increase in the availability of crab eggs to foraging birds does not result in an increase in knot numbers, managers must prioritize mitigation of limiting factors at other historically important spring stopovers and on the poorly understood breeding and wintering grounds in addition to the Delaware Bay. © 2011 The Wildlife Society.
Effects of acoustic complexity on processing sound intensity in 10‐ to 11‐year‐old children
Authors: Dinces Elizabeth , Sussman Elyse
Published: May 2011

Objectives/Hypothesis:

The environmental complexity that sounds are presented in, as well as the stimulus presentation rate, influences how sound intensity is centrally encoded with differences between children and adults.

Study Design:

Cortical auditory evoked potential (CAEP) comparison study in children and adults examining two stimulus rates and three different stimulus contexts.

Methods:

Twelve 10 and 11 year olds and 11 adults were studied in two experiments examining the CAEP to a 1‐KHz, 50‐ms tone. A Slow‐Rate experiment at 750‐ms stimulus onset asynchrony (SOA) compared the CAEPs of 78 dB to 86 dB SPL in 2 complexity conditions. A Fast‐Rate experiment was performed at 125 ms SOA with the same conditions plus an additional complexity condition. Repeated measures and mixed‐model analysis of variance (ANOVA) was used to examine the latency and amplitude of the CAEP components.

Results:

CAEP amplitudes and latencies were significantly affected by rate, intensity, and age with complexity interacting in multiple mixed‐mode ANOVAs. P1 was the only CAEP component present at the Fast Rate. There were main effects of rate, age, and stimulus intensity level on the CAEP amplitudes and latencies. Maturational differences were seen in the interactions of intensity with complexity for the different CAEP components.

Conclusions:

Complexity of the sound environment was reflected in the relative amplitude of the CAEPs evoked by sound intensity. The effect of stimulus intensity depended on the complexity of the surrounding environment. Effects of the surrounding sounds were different in children than in adults.
Hybrid Approaches to Coarse‐Graining using the VOTCA Package: Liquid Hexane
Authors: Rühle Victor , Junghans Christoph
Published: May 2011

Several systematic coarse‐graining techniques have been developed in recent years. The method of choice depends on the system of interest and the properties to be reproduced. We present three hybrid schemes to combine force‐matching and Boltzmann inversion. The methods are tested on liquid hexane and the results are compared to iterative Boltzmann inversion. All approaches can easily be extended to mixtures of molecules and provide insight for parametrizing building blocks of bigger molecules. An implementation is provided in the VOTCA package which is available under an open source software license.

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Structure‐Based Pharmacophores for Virtual Screening
Authors: Löwer Martin , Proschak Ewgenij
Published: May 2011

Pharmacophores describe the spatial arrangement of essential interactions in a receptor‐ligand complex. Although highly established in ligand‐based virtual screening, the application of pharmacophores for in absence of a ligand is more sophisticated. This article summarizes the recent approaches to derive and evaluate pharmacophore models using only limited information (e.g. a homology model of the binding site). A range of different methodologies including geometrical and/or potential‐based methods and successes in the application to virtual screening problems are described. Advantages and current limitations of the state‐of‐the‐art methods and future perspectives for development are discussed in this publication.
Time efficient design of multi dimensional RF pulses: Application of a multi shift CGLS algorithm
Authors: Sbrizzi Alessandro , Hoogduin Hans , Lagendijk Jan J. , Luijten Peter , Sleijpen Gerard L. G. , van den Berg Cornelis A. T.
Published: May 2011

Designing multi dimensional ratio frequency excitation pulses in the small flip angle regime commonly reduces to the solution of a least squares problem, which requires regularization to be solved numerically. Usually, regularization is carried out by the introduction of a penalty, λ, on the solution norm. In most cases, the optimal regularization parameter is not known a priori and the problem needs to be solved for several values of λ. The optimal value can be selected, typically by plotting the L‐curve. In this article, a conjugate gradients‐based algorithm is applied to design ratio frequency pulses in a time‐efficient way without a priori knowledge of the optimal regularization parameter. The computation time is reduced considerably (by a factor 10 in a typical set up) with respect to the standard conjugate gradients for least square since just one run of the algorithm is required. Simulations are shown and the performance is compared to that of conjugate gradients for least square. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Spuren des Lebens: Organische Verbindungen im Stein
Authors: Falk Heinz , Wolkenstein Klaus
Published: May 2011

Definierte organische Moleküle in Sedimenten und sogar Fossilien sind durchaus verbreitet: Sie sind Biomarker, die ein Fenster in urzeitliche Lebenswelten öffnen.
Süße Versuchung: De‐novo‐Wege zu ungewöhnlichen Zuckern
Authors: Brand Christian , Werz Daniel B.
Published: May 2011

Statt natürlich vorkommende Zucker zu modifizieren, setzen Chemiker zunehmend darauf, Kohlenhydratgerüste von Grund auf neu zu synthetisieren. Dabei lassen sie sich von natürlichen Vorbildern, den Aldolasen, inspirieren.
Screeningverfahren für Dioxin‐ und PCB‐Kontrollen
Authors: Herterich Roland , Schröder Stephan
Published: May 2011

Der aktuelle Entwurf zur Änderung der Futtermittelverordnung sieht vor, dass Hersteller und Überwachungsbehörden das Dioxin‐ und PCB‐Monitoring ausweiten. Probenaufkommen und die Nachfrage nach kostengünstigen Dioxin‐und PCB‐Analysen werden daher ansteigen. Erfordern diese Grenzwertprüfungen immer den Einsatz der hochauflösenden Massenspektrometrie?
Testing of the topoisomerase 1 inhibitor Genz‐644282 by the pediatric preclinical testing program
Authors: Houghton Peter J. , Lock Richard , Carol Hernan , Morton Christopher L. , Gorlick Richard , Anders Kolb E. , Keir Stephen T. , Reynolds C. Patrick , Kang Min H. , Maris John M. , Billups Catherine A. , Zhang Mindy X. , Madden Stephen L. , Teicher Beverly A. , Smith Malcolm A.
Published: May 2011

Background

Genz‐644282 is a novel non‐camptothecin topoisomerase I poison that is in clinical development.

Procedures

Genz‐644282 was tested against the PPTP in vitro panel (0.1 nM to 1 µM), and in vivo using three times per week × 2 schedule repeated at day 21 at its maximum tolerated dose (MTD) of 4 mg/kg. Subsequently Genz‐644282 was tested at 4, 3, 2, and 1 mg/kg in 3 models to assess the dose–response relationship. mRNA gene signatures predictive for Genz‐644282 response in vitro were applied to select 15 tumor models that were evaluated prospectively.

Results

In vitro, Genz‐644282 demonstrated potent cytotoxic activity with a median IC50 of 1.2 nM (range 0.2–21.9 nM). In vivo, Genz‐644282 at its MTD (4 mg/kg) induced maintained complete responses (MCR) in 6/6 evaluable solid tumor models. At 2 mg/kg Genz‐644282 induced CR or MCR in 3/3 tumor models relatively insensitive to topotecan, but there were no objective responses at 1 mg/kg. Further testing at 2 mg/kg showed that Genz‐644282 induced objective regressions in 7 of 17 (41%) models. There was a significant correlation between predictive response scores based on Affymetrix U133Plus2 baseline tumor expression profiles and the observed in vivo responses to Genz‐644282.

Conclusions

Genz‐644282 was highly active within a narrow dose range (2–4 mg/kg), typical of other topoisomerase I poisons. As with other topoisomerase I poisons, how accurately these data will translate to clinical activity will depend upon the drug exposures that can be achieved in children treated with this agent. Pediatr Blood Cancer 2012; 58: 200–209. © 2011 Wiley Periodicals, Inc.
Radial pressure and thickness effects on the moisture diffusion in hollow composite cylinders
Authors: Youssef G. , Jacquemin F. , Fréour S.
Published: May 2011

According to the literature, the mechanical states (external or internal) have an effect on the penetration of moisture into a composite material through affecting both its main controlling parameters: the diffusion coefficient and the maximum moisture absorption capacity. In this article, a scale transition analysis is performed to investigate the coupled effect of the external/internal mechanical states, experienced by epoxy resin composite structures, on the moisture penetration process. The scale transition approach provides relations linking the plies strains to those of their constituents and homogenization procedures enabling to estimate the evolution of the plies diffusion parameters, from those of the epoxy, at any step of the moisture diffusion process. This work underlines the effects induced by the thickness of the considered composite structure. The respective contributions of the internal and external loads (in the case of a radial pressure, only) on the transient and permanent stages of the diffusion process are also investigated. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Temperature‐induced volume change and glucose sensitivity of poly[(N‐isopropylacry‐ lamide)‐co‐acrylamide‐co‐(phenylboronic acid)] microgels
Authors: Farooqi Zahoor H. , Khan Abbas , Siddiq Mohammad
Published: May 2011

Nearly monodisperse glucose‐sensitive poly[(N‐isopropylacrylamide)‐co‐acrylamide‐co‐(phenylboronic acid)] microgels were synthesized in aqueous media by the functionalization of poly[(N‐isopropylacrylamide)‐co‐acrylamide‐co‐(acrylic acid)] microgels with 3‐aminophenylboronic acid via carbodiimide coupling. The glucose‐sensitive and thermosensitive behaviour of the microgels was investigated using a dynamic light scattering technique. The introduction of the hydrophobic phenylboronic acid (PBA) group significantly decreases the temperature at which maximum volume change of the resultant microgel particles is observed. The glucose sensitivity of the PBA‐containing microgels relies on the stabilization of the charged phenylborate ions by binding with glucose, which can convert more hydrophobic PBA groups to the hydrophilic phenylborate ions. The effect of pH, ionic strength and PBA content on temperature‐induced volume change and glucose sensitivity was systemically studied. The effect of NaCl on the glucose sensitivity was also investigated at physiological pH and ionic strength. Copyright © 2011 Society of Chemical Industry
Photovoltaics literature survey (no. 86)
Authors: Shrestha Santosh
Published: May 2011

In order to help keep readers up‐to‐date in the field each issue of Progress in Photovoltaics will contain a list of recently published journal articles most relevant to its aims and scope. This list is drawn from an extremely wide range of journals, including IEEE Transactions on Electron Devices, Journal of Applied Physics, Applied Physics Letters, Progress in Photovoltaics and Solar Energy Materials and Solar Cells. To assist the reader, the list is separated into broad categories, but please note that these classifications are by no means strict. Also note that inclusion in the list is not an endorsement of a paper's quality. If you have any suggestions please email Santosh Shrestha at s.shrestha@unsw.edu.au.
Entanglement properties of cellulose and amylose in an ionic liquid
Authors: Horinaka Jun‐ichi , Yasuda Ryosuke , Takigawa Toshikazu
Published: May 2011

Concentrated solutions of cellulose and amylose were prepared with an ionic liquid 1‐butyl‐3‐methylimidazolium chloride (BmimCl), which was chosen as a good solvent for these polysaccharides. Dynamic viscoelasticity of the concentrated solutions was examined to obtain the molecular weight between entanglements, Me. The value of Me in the molten state (Me,melt), a material constant that reflecting the entanglement properties, was determined for cellulose and amylose by extrapolating Me to the “melt.” A marked difference in Me,melt was found: 3.2 × 103 for cellulose and 2.5 × 104 for amylose. The value of Me,melt for cellulose, which is composed of β‐(1,4) bonding of D‐glucose units, is very close to those for polysaccharides with a random‐coil conformation such as agarose and gellan in BmimCl. The much larger Me,melt for amylose can be attributed to the helical nature of the amylose chain, α‐(1,4)‐linked D‐glucose units. The effect of concentration on the zero‐shear viscosity for the solutions of cellulose and amylose was also examined. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Acaricide resistance and resistance mechanisms in Tetranychus urticae populations from rose greenhouses in the Netherlands
Authors: Khajehali Jahangir , Van Nieuwenhuyse Pieter , Demaeght Peter , Tirry Luc , Van Leeuwen Thomas
Published: May 2011

BACKGROUND: Spider mites are important crop pests that rapidly develop resistance to acaricides. To investigate whether acaricide resistance is a threat to greenhouse rose culture in the Netherlands, the susceptibility of 15 strains of Tetranychus urticae was tested to several currently used acaricides, and resistance mechanisms were investigated.

RESULTS: Although the observed levels of susceptibility differed between strains and acaricides, resistance was detected in most strains. The activity of detoxifying enzymes was significantly increased in most field‐collected strains, and a number of amino acid substitutions known to be involved in resistance were detected.

CONCLUSIONS: Resistance levels to traditional acaricides such as bifenthrin and abamectin were prominent, and might result in control failure under field conditions. Resistance to more recently registered compounds was detected in several populations. Resistance levels were generally unstable in the laboratory without selection pressure. The toxicological, biochemical and genetic data in this study will be essential in devising an efficient resistant management for Dutch rose culture. Copyright © 2011 Society of Chemical Industry
NO2 sensing properties of WO3 nanorods grown on mica
Authors: El Achhab Mhamed , Shanak Hussein , Schierbaum Klaus
Published: May 2011

One‐dimensional nanostructures of tungsten trioxide were prepared by a simple chemical vapour deposition technique. WO3 is sublimated onto cleaved (0001) oriented mica substrates in air at atmospheric pressure. We obtained needle‐type crystals (‘nanorods’), epitaxially oriented in three directions along the principal symmetry axes of mica. Their morphology was investigated with atomic force microscopy (AFM). The WO3 structures were electrically contacted by means of four gold electrodes which were fabricated by optical lithography. In our experiments, we have analysed the NO2 sensing properties in a gas‐flow system with respect to stability, operation regimes, response and decay times, as well as cross‐sensitivity towards humidity.
Fabrication of a nanoporous dual‐electrode system for electrochemical redox cycling
Authors: Hüske Martin , Wolfrum Bernhard
Published: May 2011

Nanoporous electrodes are promising tools for highly sensitive electrochemical detection of molecules by redox cycling. In here, we report on a novel approach for the on‐chip fabrication of nanoporous dual‐electrode systems. The fabrication is based on template assisted dry etching into an electrode–insulator–electrode structure using a nanoporous alumina film as a mask. The mask itself is patterned by directly anodizing an aluminum layer on top of the chip. Homogeneous growth of the alumina nanopores on a wafer scale is achieved by adding a titanium intermediate film between the top electrode and the aluminum substrate as a stopping layer. The resulting electrodes are separated by approximately 100 nm and have pore diameters in the range of 30–50 nm. Thus they are ideally suited for redox cycling experiments based on fast diffusion of molecules between the electrodes. Integrating this process into microfabricated electrode structures promises to yield a stable and sensitive electrochemical sensor platform.

magnified image

Redox cycling scheme for a nanoporous dual‐electrode system. The close distance of anode and cathode provides a short diffusion path of oxidized and reduced molecules, as depicted by the arrows. The inlet shows a close‐up of the molecules within a pore. Different colours indicate different oxidation states.
Templating of polycrystalline ZnO with DNA and its performance in field‐effect transistors
Authors: Hoffmann Rudolf C. , Atanasova Petia , Dilfer Stefan , Bill Joachim , Schneider Jörg J.
Published: May 2011

Field effect transistors (FET) with bottom gate/bottom contact arrangement are constructed using composites of deoxyribonucleic acid (DNA) and nanoparticulate zinc oxide as semiconductor. Polycrystalline ZnO, is tethered onto double stranded DNA by means of a chemical bath deposition (CBD) technique at about 60 °C. In the FET device the DNA/ZnO composite wires bridge the source and drain geometry in a stochastic arrangement. The carrier charge mobility was extracted as 5.52 × 10−5 cm2/V s; Ion/off ∼ 52.500 as well as Vth + 9.07 V. The device performance was obtained from as deposited material without further annealing. The presence of the DNA structure directing template seems to be beneficial for the FET performance.

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Preface: Phys. Status Solidi C 5/2011
Authors: Alexandropoulos Dimitris , Rorison Judy , Balkan Naci , Erol Ayse , Marie Xavier
Published: May 2011

III–V semiconductors are indispensable for today's optoelectronic devices such as la‐sers used in optical communication systems. Likewise, this class of material is dominant in key high frequency electronics components for wireless com‐munication systems. The miscibility of binary III–Vs and the possibility of stacking such layers of various compositions and doping levels are crucial for all these applications. The tailoring of het‐erostructure properties is limited by the different lat‐tice constants of the binary III–Vs, which limit the range of useful compositions and thereby the range of available band gaps. The alignment of the band edges, which is very important for the perfor‐mance of devices, cannot be tailored by the combina‐tion of conventional materials at all. These limitations encountered in InP and GaAs based devices can be greatly reduced by incorporating a few percent of N or Bi as a group V element into GaAs or InGaAs, i.e. by creating the so‐called “Dilute Nitrides”.

The second class of III–V–nitrides is based on the In1–xGaxN compound. It was discovered in 2001 that InN has a much smaller fundamental energy gap than was believed hitherto [1]. As a consequence the range of wavelengths that can be accessed by alloying this material with gallium nitride (GaN) has been significantly extended. Indeed GaInN has the widest range of direct gap of any compound semiconductors ranging from 0.7 eV to 3.2 eV which can be utilized in optoelectronic device applications over a wide range of wavelengths, including numerous key wavelengths for applications in the medical, environmental and communications fields.

This issue of physica status solidi contains a collection of the articles presented during the 2010 E‐MRS Spring Meeting 2010, Symposium G, entitled “Physics and Applications of Novel Gain Ma‐terials based on III–V–N Com‐pounds”. The symposium was a follow up to a similar session held at E‐MRS in 2007. In 2007 there were fifty participants while the session in 2010 which was organised in collaboration with COST Action MP 0805 attracted over 100 participants. This increase in the number of attendants is indicative of the growing interest in III–V–dilute nitride compound semiconductors for potential applications in future devices. The symposium comprised 30 oral presentations, including 7 invited presentations and 50 poster presentations covering a wide range of dilute‐nitride and In1–xGaxN compound research from growth and structural properties, transport and optical properties to device applications.