bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phenylalanine: Its ˙OH and SO4˙⁻-Induced Oxidation and Decarboxylation. A Pulse Radiolysis and Product Analysis Study
Authors: Wang Degui , Schuchmann Heinz-Peter , von Sonntag Clemens 
Published: March 2015

Phenylamine has been oxidized by radiolytically generated hydroxyl and sulfate radicals, the ensuing intermediates and their reactions have been studied by pulse radiolysis and product analysis in the absence and presence of oxidants such as Fe(CN)6
3- and O2. Upon OH radical attack, hydroxycyclohexadienyl-type radicals are mainly formed while Η-abstraction reactions can be neglected. In the presence of Fe(CN)6
3- these radicals are for the most part oxidized to the corresponding tyrosines (80%), except for the ipso-OH-adduct radicals (≈ 20%). It is concluded that ˙OH-addition is almost random, but with a slight avoidance of the metaposition relative to the ortho-, para- and ipso-positions. Oxygen adds reversibly to the OH-adduct radicals (kf = 1.8 × 108 dm3 mol-1 s-1, kr = 5.4 × 104 s-1). In this case, tyrosine formation occurs by HO2˙-elimination. However, due to side reactions, tyrosine formation only reaches 52% of the OH radical yield. The tyrosine yield drops to 10% in the absence of an oxidant.
Upon SO4˙⁻-attack, decarboxylation becomes a major process (33% of SO4˙⁻) alongside the production of tyrosines (43%). Here, with Fe(CN)6
3- as the oxidant the formation of p-Tyr (18.5%) and m-Tyr (16.5%) is preferred over o-Tyr formation (8.5%). It is believed that in analogy to other systems a radical cation is formed immediately upon SO4˙⁻-attack which either reacts with water under the formation of hydroxycyclohexadienyl-type (“OH-adduct”) radicals, or decarboxylates after intramolecular electron transfer. The radical cation can also arise indirectly through H+-catalysed water elimination from the ˙OH-adduct radicals. At pH 2 and a dose rate of 0.0046 Gy s-1 CO2 formation matches the OH radical yield when ˙OH is the attacking radical. Below pH 2, G(CO2) decreases with falling pH. This indicates the occurrence of another, unimolecular, pathway under these conditions competing effectively with decarboxylation. This appears to be a relatively slow deprotonation reaction of the carboxylprotonated phenylalanine radical cation which gives rise to the benzyl-type radical.
Thiocarbonyl Complexes of Rhenium. Part I.
Authors: Abram Ulrich , Lorenz Bernd 
Published: March 2015

Novel rhenium complexes with terminal thiocarbonyl groups have been synthesized from ReCl3(Me2PhP)3 and sodium diethyldithiocarbamate. mer-(Diethyldithiocarbamato)tris-(dimethylphenylphosphine)(thiocarbonyl)rhenium(I), mer-[Re(CS)(Me2PhP)3(Et2dtc)], and tris(diethyldithiocarbamato)(thiocarbonyl)rhenium(III), [Re(CS)(Et2dtc)3] have been studied by infrared and NMR spectroscopy, mass spectrometry and X-ray diffraction.
mer-[Re(CS)(Me2PhP)3(Et2dtc)] crystallizes orthorhombic in the space group Pna21 with a = 1516.1(2), b = 2189.8(2) and c = 1035.6(1) pm. Structure solution and refinement converged at R = 0.042. The coordination geometry is a distorted octahedron. The Re—C bond length is found to be 184(2) pm.
[Re(CS)(Et2dtc)3] crystallizes monoclinic in the space group P21/c with a = 962.2(6), b = 1744.0(2), c = 1537.4(6) pm and β = 96.21(1)°. The final R value is 0.028. In the monomeric complex the rhenium atom is seven-coordinate with an approximate pentagonal-bipyramidal coordination sphere and a rhenium-carbon distance of 181(1) pm.
Antagonists of LHRH with Histidine in the Priority Position 8
Authors: Janecka Anna , Shan Si-Mei , Bowers Cyril , Folkers Karl 
Published: March 2015

Sixteen new designs of antagonists of the luteinizing hormone releasing hormone (LHRH) with histidine in position 8 were synthesized, because this position is critical both for antiovulatory activity and the side effect of histamine release. The most potent antagonist was NAcDQal-DpClPhe–D 3 Pal– Ser–cPzACAla–DPicLys– Leu– His – Pro –DAlaNH2, which showed 33% AOA at 0.25 μg. The histamine release was remarkably negligible by an ED50 of 308 μg/ml which is superior to 186 μg/ml for LHRH and comparable to 300 for Antide.
The relative basicities of His, Arg, and ILys in position 8 of antagonists appear to influence both the level of potency of AOA and a negligible to a significant release of histamine. The least basic His8-analogs can have the lowest AOA and the highest ED50. The very basic Arg8-analogs can have the highest AOA and the lowest ED50. The moderately basic ILys8-analogs can be a compromise for acceptable levels of potency and safety.
Notizen: Auflösung von Palladium- und Platinpulver durch biogene Stoffe / Dissolution of Palladium and Platinum Powder by Biogenic Compounds
Authors: Freiesleben Doris , Wagner Barbara , Hartl Helmut , Beck Wolfgang , Hollstein Michael , Lux Franz 
Published: March 2015

Palladium and platinum powder dissolve at room temperature in oxygen saturated solutions of α-amino acids, peptides, nucleosides and ATP.
The resulting mass concentrations of dissolved palladium and platinum were in the range from 10 to 100 μg/ml.
Synthese und Kristallstrukturen der Wolfram(VI)-Alkinkomplexe [WCl4(Ph - C≡C - I)(THF)] und [WCl4(Ph-C≡C-Te-C4H9)(THF)] / Synthesis and Crystal Structures of the Tungsten(VI) Alkyne Complexes [WCl4(Ph-C≡C-I)(THF)] and [WCl4(Ph-C≡C-Te-C4H9)(THF)]
Authors: Plate Michael , Hofacker Peter , Massa Werner , Schwarz Birgit , Neumüller Bernhard , Dehnicke Kurt 
Published: March 2015

[WCl4(Ph-C≡C-I)(THF)] has been prepared by the reaction of trans-[WCl4(SEt2)2] with Ph - C≡C - I in THF solution, whereas [WCl4(Ph-C≡C-Te-nC4H9)(THF)] has been synthesized by the reaction of Ph-C≡C-Te-nC4H9 with tungsten hexacloride in the presence of C2Cl4 and THF. Both complexes were characterized by IR spectroscopy and by crystal structure determinations.
[WCl4(Ph-C≡C-I)(THF)]: Space group P21/c, Z = 4, 2617 observed unique reflections, R = 0.064. Lattice dimensions at –70°C: a = 1518.2(3), b = 714.5(1), c = 1540.0(3) pm, β = 90.09(3)°.
[WCl4(Ph-C≡C-Te–nC4H9)(THF)]. Space group P1̄, Z = 2, 3911 observed unique reflections, R = 0.067. Lattice dimensions at 20°C: a = 844.0(3), b = 974.6(4), c = 1002.4(3) pm, α = 76.00(4), β= 105.14(1), γ = 82.03(3)°.
Both complexes have molecular structures, in which the tungsten atoms are seven-coordi-nate by four chlorine ligands, by the two alkyne carbon atoms, and in trans position to the latter by the oxygen atom of the THF molecule. The WC bond lengths are 198 and 200(1) in the telluro complex and 206 and 196(1) pm in the iodine derivative.
Ionische Kronenetherkomplexe von Thallium(I), Blei(II) und Indium(III). Die Kristallstrukturen von [T1(12-Krone-4)2] [SbC6], [Pb(15-Krone-5)2] [SbCl6]2 • [SbCl3(15-Krone-5)] und [In(12-Krone-4)2] [SbCl6]3· 3 CH3CN / Ionic Crown Ether Complexes of Thallium(I), Lead(II), and Indium(III). Crystal Structures of [T1(12-Crown-4)2][SbCl6], [Pb(15-Crown-5)2] [SbCl6]2 • [SbCl3(15-Crown-5)], and [In(12-Crown-4)2] [SbCl6]3 · 3 CH3CN
Authors: Arnim Henning von , Dehnicke Kurt , Maczek Klaus , Fenske Dieter 
Published: March 2015

The ionic crown ether complexes [Tl(12-crown-4)2][SbCl6] (1) and [In(12-crown-4)2][SbCl6]3·3 CH3CN (3) have been prepared by reaction of T1C1 and InCl3, respectively, with SbCl5 in the presence of 12-crown-4 in acetonitrile solution. The lead complex [Pb(15-crown-5)2][SbCl6]2· [SbCl3(15-crown-5)] (2) has been obtained from the reaction of Pb(CH3)2Cl2 with SbCl5 in the presence of 15-crown-5 in acetonitrile solution. 1-3 were characterized by crystal structure determinations.
[Tl(12-crown-4)2][SbCl6] (1): Space group C2/c, Z = 4, 2306 observed unique reflections, R = 0.051. Lattice dimensions at -70°C: a = 2360.9(5), b = 1189.6(2), c = 1080.4(3) pm, β = 111.14(2)°. 1 contains cations [Tl(12-crown-4)2]+, in which the Tl+ ion is coordinated sandwichlike by the eight oxygen atoms of the two crown ether molecules. The lone pair at the thallium ion shows steric activity.
[Pb(15-crown-5)2][SbCl6]2·[SbCl3(15-crown-5)] (2): Space group Pna2(1), Z = 4, 4631 observed unique reflections, R = 0.048. Lattice dimensions at -70°C: a = 2972.5(3), b = 1481.9(5), c = 1305.5(1) pm. 2 consists of [Pb(15-crown-5)2]2+ ions, in which the lead ion is coordinated sandwich-like by the ten oxygen atoms of the two crown ether molecules without steric activity of the lone pair of Pb2+, of SbCl6- ions, and of molecules [SbCl3(15-crown-5)], which are already known.
[In(12-crown-4)2][SbCl6]3·3CH3CN (3): Space group P1̅, Z = 2, 5530 observed unique reflections, R = 0.059. Lattice dimensions at -70°C: a = 1041.8(8), b = 1052(1), c = 1543(2) pm, α = 103.62(9)°, β=108.68(8)°, γ = 99.48(8)°. 3 consists of [In(12-crown-4)2]3+ ions, SbCl6- anions, and crystal CH3CN molecules. The In3+ ion is coordinated sandwich-like by the eight oxygen atoms of the two crown ether molecules, which are disordered in two positions
Modeling X-Linked Ancestral Origins in Multiparental Populations
Authors: Zheng Chaozhi 
Published: March 2015

Abstract
The models for the mosaic structure of an individual’s genome from multiparental populations have been developed primarily for autosomes, whereas X chromosomes receive very little attention. In this paper, we extend our previous approach to model ancestral origin processes along two X chromosomes in a mapping population, which is necessary for developing hidden Markov models in the reconstruction of ancestry blocks for X-linked quantitative trait locus mapping. The model accounts for the joint recombination pattern, the asymmetry between maternally and paternally derived X chromosomes, and the finiteness of population size. The model can be applied to various mapping populations such as the advanced intercross lines (AIL), the Collaborative Cross (CC), the heterogeneous stock (HS), the Diversity Outcross (DO), and the Drosophila synthetic population resource (DSPR). We further derive the map expansion, density (per Morgan) of recombination breakpoints, in advanced intercross populations with L inbred founders under the limit of an infinitely large population size. The analytic results show that for X chromosomes the genetic map expands linearly at a rate (per generation) of two-thirds times 1 – 10/(9L) for the AIL, and at a rate of two-thirds times 1 – 1/L for the DO and the HS, whereas for autosomes the map expands at a rate of 1 – 1/L for the AIL, the DO, and the HS.
A Multipurpose, High-Throughput Single-Nucleotide Polymorphism Chip for the Dengue and Yellow Fever Mosquito, Aedes aegypti
Authors: Evans Benjamin R , Gloria-Soria Andrea , Hou Lin , McBride Carolyn , Bonizzoni Mariangela , Zhao Hongyu , Powell Jeffrey R 
Published: March 2015

Abstract
The dengue and yellow fever mosquito, Aedes aegypti, contributes significantly to global disease burden. Genetic study of Aedes aegypti is essential to understanding its evolutionary history, competence as a disease vector, and the effects and efficacy of vector control methods. The prevalence of repeats and transposable elements in the Aedes aegypti genome complicates marker development and makes genome-wide genetic study challenging. To overcome these challenges, we developed a high-throughput genotyping chip, Axiom_aegypti1. This chip screens for 50,000 single-nucleotide polymorphisms present in Aedes aegypti populations from around the world. The array currently used genotypes 96 samples simultaneously. To ensure that these markers satisfy assumptions commonly made in many genetic analyses, we tested for Mendelian inheritance and linkage disequilibrium in laboratory crosses and a wild population, respectively. We have validated more than 25,000 of these markers to date, and expect this number to increase with more sampling. We also present evidence of the chip’s efficacy in distinguishing populations throughout the world. The markers on this chip are ideal for applications ranging from population genetics to genome-wide association studies. This tool makes rapid, cost-effective, and comparable genotype data attainable to diverse sets of Aedes aegypti researchers, from those interested in potential range shifts due to climate change to those characterizing the genetic underpinnings of its competence to transmit disease.
Differential Regulation of Antagonistic Pleiotropy in Synthetic and Natural Populations Suggests Its Role in Adaptation
Authors: Yadav Anupama , Radhakrishnan Aparna , Bhanot Gyan , Sinha Himanshu 
Published: March 2015

Abstract
Antagonistic pleiotropy (AP), the ability of a gene to show opposing effects in different phenotypes, has been identified in various life history traits and complex disorders, indicating its fundamental role in balancing fitness over the course of evolution. It is intuitive that natural selection might maintain AP to allow organisms phenotypic flexibility in different environments. However, despite several attempts, little evidence exists for its role in adaptation. We performed a meta-analysis in yeast to identify the genetic basis of AP in bi-parental segregants, natural isolates, and a laboratory strain genome-wide deletion collection, by comparing growth in favorable and stress conditions. We found that whereas AP was abundant in the synthetic populations, it was absent in the natural isolates. This finding indicated resolution of trade-offs, i.e., mitigation of trade-offs over evolutionary history, probably through accumulation of compensatory mutations. In the deletion collection, organizational genes showed AP, suggesting ancient resolutions of trade-offs in the basic cellular pathways. We find abundant AP in the segregants, greater than estimated in the deletion collection or observed in previous studies, with IRA2, a negative regulator of the Ras/PKA signaling pathway, showing trade-offs across diverse environments. Additionally, IRA2 and several other Ras/PKA pathway genes showed balancing selection in isolates of S. cerevisiae and S. paradoxus, indicating that multiple alleles maintain AP in this pathway in natural populations. We propose that during AP resolution, retaining the ability to vary signaling pathways such as Ras/PKA, may provide organisms with phenotypic flexibility. However, with increasing organismal complexity AP resolution may become difficult. A partial resolution of AP could manifest as complex human diseases, and the inability to resolve AP may play a role in speciation. Our findings suggest that testing a universal phenomenon like AP across multiple experimental systems may elucidate mechanisms underlying its regulation and evolution.
Genetic and Genomic Toolbox of Zea mays
Authors: Nannas Natalie J , Dawe R Kelly 
Published: March 2015

Abstract
Maize has a long history of genetic and genomic tool development and is considered one of the most accessible higher plant systems. With a fully sequenced genome, a suite of cytogenetic tools, methods for both forward and reverse genetics, and characterized phenotype markers, maize is amenable to studying questions beyond plant biology. Major discoveries in the areas of transposons, imprinting, and chromosome biology came from work in maize. Moving forward in the post-genomic era, this classic model system will continue to be at the forefront of basic biological study. In this review, we outline the basics of working with maize and describe its rich genetic toolbox.
Structural Tuning Using a Novel Membrane Reactor for Carbon Nanotube Synthesis
Authors: Sheppard Dane J. K. , Chibante L. P. Felipe 
Published: March 2015

ABSTRACTCarbon nanotubes come in many varieties, with chemical, mechanical, and electrical properties depending on carbon nanotube (CNT) structural morphology. In order to provide a platform for CNT structural tuning, a membrane reactor was designed and constructed. This reactor provided more intimate gas-catalyst contact by decoupling the carbon feedstock gas from carrier gas in a chemical vapour deposition (CVD) environment using an asymmetric membrane and a macroporous membrane. Growth using this membrane reactor demonstrated normalized yield improvements of ∼300% and ∼1000% for the asymmetric and macroporous membrane cases, respectively, over standard CVD methods. To illustrate the possibility for control, growth variation with time was successfully demonstrated by growing vertically aligned multi-walled CNTs to heights of 0.71 mm, 1.36 mm, and 1.84 mm after growth for 15, 30, and 60 minutes in a commercial thermal CVD reactor. To demonstrate CNT diameter control via catalyst particle size, dip coating and spray coating methods were explored using ferrofluid and Fe(NO3)3 systems. CNT diameter was demonstrated to increase with increasing particle size, yielding CNT like growth with diameters ranging from 15 -150 nm. Demonstration of these dimensions of control coupled with the dramatic efficiency increases over growth in a commercialized CVD reactor establish this new reactor technology as a starting point for further research into CNT structural tuning.
New Fracture-Stimulation Designs and Completion Techniques Result in Better Performance of Shallow Chittim Ranch Wells
Authors: Pandey Vibhas J. , Agreda Aquiles J. 
Published: March 2015

Summary
The Sacatosa field in west Texas was discovered in 1956. Since then, more than 1,500 wells have been drilled and completed in the main reservoir section known as the San Miguel 1. The San Miguel 1 is primarily low-permeability sandstone, with several shale layers dispersed throughout. Economic development of the field requires effective well stimulation and an active waterflood program to provide pressure maintenance. Unfortunately, the available injection water is of poor quality and can rapidly plug up pore throats with solids, resulting in significant near-wellbore formation damage. When these factors are considered, hydraulic fracturing of both injector and producer wells is a viable option for improved long-term well performance. However, because of relatively shallow depths, traditional hydraulic-fracturing practices can lead to a multiplane fracture system with a mix of horizontal and vertical components. A significant presence of horizontal fractures can be detrimental to fractured-well performance because of the low conductivities of the fractures. In producer wells, this could impair production if the reservoir is laminated and has low vertical permeability. In injectors, water-front movement and sweep efficiency would be diminished greatly.
This paper discusses the steps taken to plan and develop a strategy to place vertical fractures in shallow San Miguel 1 sands. These findings can easily be extended to similar shallow-depth reservoirs worldwide. Some major modifications in completion design included changes in perforation strategy, redesign of the pump schedule, and implementation of a staged stimulation. Fracturing treatments were pumped on a total of 26 injectors and eight producers through a variety of methods, including coiled-tubing fracturing. Post-fracture analysis suggests a strong vertical-fracture component, and analysis of injectivity tests shows fracture parameters in line with design objectives. All the producers that were fracture stimulated with this technique reported higher initial production when compared with wells stimulated through the use of legacy treatment schedules.
Simulation of Gel Filter-Cake Formation, Gel Cleanup, and Post-Fracture Well Performance in Hydraulically Fractured Gas Wells
Authors: Charoenwongsa Sarinya , Kazemi Hossein , Fakcharoenphol Perapon , Miskimins Jennifer L. 
Published: March 2015

SummaryPolymer and gel damage is a major issue in the cleanup of hydraulically fractured gas wells. This paper addresses the issue by using a gas/water flow model that simulates fracture propagation with gel filter cake-formation as mechanical trapping of polymer molecules on the fracture face and filtrate transport into the adjacent matrix. The model accounts for polymer as a chemical component. This approach is different than treating polymer as a highly viscous gel phase, which is the common method in most literature. In this model, the gel filter-cake thickness is calculated on the basis of experimental data. For leakoff, the model allows only the sheared polymer molecules, which are the major cause of formation permeability reduction, to cross the fracture face into the formation and adsorb on the matrix. Other features of the model include water blockage, non-Newtonian flow, non-Darcy flow, and proppant and reservoir compaction.
Laboratory Measurement of Hydraulic-Fracture Conductivities in the Barnett Shale
Authors: Zhang J.. , Kamenov A.. , Zhu D.. , Hill A.D.. D. 
Published: March 2015

Summary
Horizontal wells that intersect multistage transverse fractures created by low-viscosity fracturing fluid with low proppant loadings are the key to revitalizing production from the Mississippian Barnett shale in the Fort Worth basin in Texas. However, direct laboratory measurements of both natural- and induced-fracture conductivities under realistic experimental-design conditions are needed for reliable well-performance analysis and fracture-design optimization.
In this work, a series of experiments was conducted to measure the conductivity of unpropped natural fractures, propped natural fractures, unpropped induced fractures, and propped induced fractures with a modified American Petroleum Institute (API) conductivity cell at room temperature. Fractures were induced along the natural bedding planes, preserving fracture-surface asperities. Natural-fracture infill was taken into consideration during conductivity measurements. Proppants of various sizes were placed manually between rough fracture surfaces at realistic concentrations. The two sides of the rough fractures either were aligned or were displaced with a 0.1-in. offset. After pressure testing on the system integrity, nitrogen was flowed through the proppant pack or unpropped fracture to measure the conductivity.
Results from 88 experiments show that the conductivity of hydraulic fractures in shale can be measured accurately in a laboratory with appropriate experimental procedures and good control over experimental errors. It is proved that unpropped, aligned fractures can provide a conductive path after removal of free particles and debris because of the brittleness and lamination of shale. Moreover, poorly cemented natural fractures and unpropped displaced fractures can create conductivities of up to 0.5 md-ft at formation-closure stress, which is one to two orders of magnitude greater than the conductivity provided by cemented natural fractures and unpropped aligned fractures. This study shows that propped-fracture conductivity increases with larger proppant size and higher proppant concentration. Longer-term fracture-conductivity measurements indicate that, within 20 hours, the fracture conductivity could be reduced by as much as 20%.