bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology development and crystallization behavior of poly(ethylene terephthalate)/phenoxy blend
Authors: Kim Geon Seok , Lee Jong Kwan , Choi Mi Ju , Lee Kwang Hee 
Published: December 2007

AbstractThe morphological development and crystallization behavior of a poly(ethylene terephthalate)/poly(hydroxyl ether of bisphenol A) (phenoxy) blend were studied with time‐resolved light scattering, optical microscopy, differential scanning calorimetry, and small‐angle X‐ray scattering (SAXS). During annealing at 280 °C, liquid–liquid phase separation via spinodal decomposition proceeded in the melt‐extruded specimen. After the formation of a domain structure, the blend slowly underwent phase homogenization by the interchange reactions between the two polymers. Specimens annealed for various times (ts) at 280 °C were subjected to a temperature drop and the effects of liquid‐phase changes on crystallization were then investigated. The shifts in the position of the cold‐crystallization peaks indicated that the crystallization rate is associated with the composition change of the separated phases as well as the change of the sequence distribution in polymer chains during annealing. The morphological parameters at the lamellar level were determined by a correlation function analysis on the SAXS data. The crystal thickness (lc) increased with ts, whereas the amorphous layer thickness (la) showed little dependence on ts. Observation of a constant la value revealed that a large number of noncrystallizable species formed by the interchange reactions between the two polymers were excluded from the lamellar stacks and resided in the interfibrillar regions, interspherulitic regions, or both. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 223–232, 2008
Simulation modelling to understand the evolution and management of glyphosate resistance in weeds
Authors: Neve Paul 
Published: December 2007

AbstractBACKGROUND: A simulation model is used to explore the influence of biological, ecological, genetic and operational (management) factors on the probability and rate of glyphosate resistance in model weed species.RESULTS: Glyphosate use for weed control prior to crop emergence is associated with low risks of resistance. These low risks can be further reduced by applying glyphosate in sequence with other broad‐spectrum herbicides prior to crop seeding. Post‐emergence glyphosate use, associated with glyphosate‐resistant crops, very significantly increases risks of resistance evolution. Annual rotation with conventional crops reduces these risks, but the proportion of resistant populations can only be reduced to close to zero by mixing two of three post‐emergence glyphosate applications with alternative herbicide modes of action. Weed species that are prolific seed producers with high seed bank turnover rates are most at risk of glyphosate resistance evolution. The model is especially sensitive to the initial frequency of R alleles, and other genetic and reproductive parameters, including weed breeding system, dominance of the resistance trait and relative fitness, influence rates of resistance.CONCLUSION: Changing patterns of glyphosate use associated with glyphosate‐resistant crops are increasing risks of evolved glyphosate resistance. Strategies to mitigate these risks can be explored with simulation models. Models can also be used to identify weed species that are most at risk of evolving glyphosate resistance. Copyright © 2007 Society of Chemical Industry
Influence of imidacloprid seed treatments on rice germination and early seedling growth
Authors: Stevens Mark M , Reinke Russell F , Coombes Neil E , Helliwell Stuart , Mo Jianhua 
Published: December 2007

AbstractBACKGROUND: Seed treatments with the chloronicotinyl insecticide imidacloprid (Gaucho® 600 FS) were evaluated to determine whether differences in concentration and exposure regime influence the germination and early growth of rice.RESULTS: Continuous exposure to imidacloprid (4 days at 2000 mg AI L−1) significantly (P < 0.001) reduced normal germination by an average of 18% across the 15 cultivars examined. Nine days after sowing, plants showed no adverse effects from continuous imidacloprid treatment during germination, with shoot lengths and root system dry weights equalling, or occasionally exceeding (P < 0.05), those of untreated plants. Short‐term imidacloprid exposure (2 h at 2000 mg L−1) at initial seed wetting did not affect germination (P > 0.05), and short‐term (1 h) exposure of 48 h pregerminated seed to imidacloprid (2000 mg L−1) similarly had no significant effect on early subsequent growth. Plants arising from 48 h pregerminated seed exposed to imidacloprid (1 h) at concentrations up to 4000 mg L−1 immediately before sowing were not significantly different from control plants at either 9 or 25 days post‐sowing.CONCLUSION: Results show that imidacloprid will have no adverse effects on plant growth if applied to pregerminated rice shortly before sowing. Continuous exposure of seed during germination had more pronounced effects, and the initial response of different cultivars was highly variable. Cultivars with high levels of sensitivity (such as IR72) require further testing before continuous exposure to imidacloprid during germination can be recommended. Copyright © 2007 Society of Chemical Industry
Managing the risk of glyphosate resistance in Australian glyphosate‐ resistant cotton production systems
Authors: Werth Jeff A , Preston Christopher , Taylor Ian N , Charles Graham W , Roberts Grant N , Baker Jeanine 
Published: December 2007

AbstractBACKGROUND: Glyphosate‐resistant cotton varieties are an important tool for weed control in Australian cotton production systems. To increase the sustainability of this technology and to minimise the likelihood of resistance evolving through its use, weed scientists, together with herbicide regulators, industry representatives and the technology owners, have developed a framework that guides the use of the technology. Central to this framework is a crop management plan (CMP) and grower accreditation course. A simulation model that takes into account the characteristics of the weed species, initial gene frequencies and any associated fitness penalties was developed to ensure that the CMP was sufficiently robust to minimise resistance risks.RESULTS: The simulations showed that, when a combination of weed control options was employed in addition to glyphosate, resistance did not evolve over the 30 year period of the simulation.CONCLUSION: These simulations underline the importance of maintaining an integrated system for weed management to prevent the evolution of glyphosate resistance, prolonging the use of glyphosate‐resistant cotton. Copyright © 2007 Society of Chemical Industry
Pyrimidinyl‐substituted amides and thioureas: syntheses, crystal structure and herbicidal activities
Authors: Liu Guo‐Hua , Xue Yun‐Ning , Lu Xiao‐Quan , Liu Mou‐Ming , Wang Wei‐Ying , Yang Liang‐Zhun 
Published: December 2007

AbstractBACKGROUND: The high herbicidal activities of [1,2,4]triazolo[1,5‐c]pyrimidine and 2H‐1,2,4‐thiadiazolo[2,3‐a]pyrimidine derivatives suggested the development of new fused heterocyclic compounds for application as herbicides.RESULTS: Three series of pyrimidinyl‐substituted thioureas (4) and amides (5, 6) were synthesized, and the typical crystal structure of a 2H‐1,2,4‐thiadiazolo[2,3‐a]pyrimidine derivative (5a) was determined by X‐ray diffraction. All the compounds were tested for herbicidal activity against selected weeds.CONCLUSION: The series of fused heterocyclic amides 5a to 5d exhibited high herbicidal activities both against monocotyledonous weeds (Echinochloa crus‐galli L., Sorghum bicolor (L.) Mönch., Digitaria sanguinalis (L.) Scop) and against dicotyledonous weeds (Amaranthus retroflexus L. and Brassica campestris L.) in pre‐emergence treatments. In particular, compound 5b at low concentration still showed high inhibitory activity against A. retroflexus in pre‐emergence treatment. Different substituents at the meta positions of the pyrimidine ring were found to affect the herbicidal activity. Copyright © 2007 Society of Chemical Industry
Aggregation and membrane permeabilizing properties of designed histidine‐containing cationic linear peptide antibiotics
Authors: Marquette Arnaud , Mason A. James , Bechinger Burkhard 
Published: December 2007

AbstractMembers of the LAH4 family of cationic linear peptide antibiotics have been designed to form amphipathic helical structures in membrane environments and switch from alignments parallel to the bilayer surface to transmembrane orientations in a pH‐dependent manner. Here the aggregation in aqueous buffer of two members of the family has been investigated by DLS. The peptides form monomers or small oligomers at pH = 5 but associate into nano‐sized aggregates at physiological pH. The diameter of these latter complexes can be considerably reduced by sonication. Furthermore, the membrane interactions of the various supramolecular aggregates with POPC or mixed POPC/POPS vesicles have been investigated in calcein‐release assays. In all the cases tested, the large preformed oligomeric peptide aggregates of 20–40 nm in size were more active than the structures with the smallest hydrodynamic radii in releasing the fluorescent dye from LUV. In contrast, the relative activity after sonication depends on the specific environment tested. The data suggest that these amphiphiles form micellar structures and support the notion that they can act in a manner comparable to detergents. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Liquid phase deposited silicon oxide with lower boron impurity grown on gallium nitride by temperature‐difference method
Authors: Lee Ming‐Kwei , Ho Chen‐Lin , Zeng Jia‐Yi 
Published: December 2007

AbstractThis study investigates the growth of silicon oxide film on gallium nitride using hydrosilicofluoric acid and silica gel by the temperature‐difference liquid‐phase deposition. In the conventional liquid phase deposition, the boric acid is used as fluorine scavenger to prompt silicon oxide deposition and it also acts as an impurity in the oxide film. The better metal–oxide–semiconductor diode electrical characteristics can be obtained by the temperature‐difference method with lower boric acid incorporation and higher deposition rate. Compared with the leakage current density of the conventional and temperature‐difference methods, it can be much improved from 9.93 × 10–2 A/cm2 to 5.8 × 10–4 A/cm2 at +2 MV/cm and from 1.35 × 10–2 A/cm2 to 5.15 × 10–4 A/cm2 at –1 MV/cm. The effective oxide charges is improved from 3.88 × 1011 cm–2 to 2.27 × 1011 cm–2. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exploring event‐related brain dynamics with tests on complex valued time–frequency representations
Authors: Martínez‐Montes Eduardo , Cuspineda‐Bravo Elena R. , El‐Deredy Wael , Sánchez‐Bornot José M. , Lage‐Castellanos Agustín , Valdés‐Sosa Pedro A. 
Published: December 2007

AbstractA question subject to intense debate is whether scalp‐recorded event‐related brain potentials are due to phase resetting of the ongoing electroencephalogram (EEG) or rather to the superimposition of time‐locked components on background activity. The two hypotheses are usually assessed by means of statistics in the time–frequency domain, for example, through wavelet transformation of multiple EEG trials that yield for each time and frequency a scatter plot of complex values coefficients. Currently, intertrial phase correlation (phase locking or phase coherence) is taken as evidence for phase resetting at a given frequency and latency. Here we present a formal analysis using a complex t‐statistic to illustrate that such measures are, in effect, tests for the mean vector of the repeated trials, and as such on their own are inappropriate measures of phase resetting. We also propose simple t‐like statistics for testing changes in (i) the mean (presence of an event‐related potential), (ii) the amplitude variance (presence of (de)synchronization) and (iii) the concentration of phases (phase locking). The first two statistics are found to be proper measures of the presence of a non‐zero mean activity and induced activity, respectively. In the third case, two different tests are introduced: one based on measuring the alignment of coefficients in the complex plane and another derived from the argument that phase locking persists when the mean of the coefficients is removed. Both statistics gave unambiguous evidence of the presence of phase locking suggesting that they constitute promising tools in the analysis of event‐related brain dynamics. Copyright © 2007 John Wiley & Sons, Ltd.
Tuning mechanisms for two major parameters of Apache web servers
Authors: Sugiki Akiyoshi , Kono Kenji , Iwasaki Hideya 
Published: December 2007

AbstractApache web servers are widely used as stand‐alone servers or front‐ends in multi‐tiered web servers. Despite the wide availability of software, it is quite difficult for many administrators to properly configure their web servers. In particular, setting the performance‐related parameters is an error‐prone and time‐consuming task because their values heavily depend on the server environment. In this paper, two mechanisms are described for automatically tuning two performance‐related parameters of Apache web servers:KeepAliveTimeoutandMaxClients. These mechanisms are easy to deploy because no modifications to the server or the operating system are required. Moreover, they are parameter specific. Although interference betweenKeepAliveTimeoutandMaxClientsis inevitable, the tuning mechanisms minimize the correlation by using almost completely independent metrics. Experimental results show that these mechanisms work well for two different workloads; the parameter values are close to optimal and can adapt to workload changes. Copyright © 2007 John Wiley & Sons, Ltd.
In vivo measurement of nicotinic acetylcholine receptors with [18F]norchloro‐fluoro‐homoepibatidine
Authors: Brust Peter , Patt Jörg Thomas , Deuther‐Conrad Winnie , Becker Georg , Patt Marianne , Schildan Andreas , Sorger Dietlind , Kendziorra Kai , Meyer Philipp , Steinbach Jörg , Sabri Osama 
Published: December 2007

AbstractFunctional changes of nicotinic acetylcholine receptors (nAChR) are important during age‐related neuronal degeneration. Recent studies demonstrate the applicability of the nAChR ligand 2‐[18F]F‐A‐85380 for neuroimaging of patients with dementias. However, its binding kinetics demands a 7‐h acquisition time limiting its practicality for clinical PET studies. Thus, the authors developed [18F]norchloro‐fluoro‐homoepibatidine ([18F]NCFHEB) for nAChR imaging. The kinetics of the two enantiomers of [18F]NCFHEB were compared with 2‐[18F]F‐A85380 in porcine brain to evaluate their potential for human neuroimaging. Twenty‐four juvenile female pigs were studied with PET using [18F]NCFHEB. Nine animals received an additional i.v. injection (1 mg/kg) of the nAChR agonist A81418 before radiotracer administration followed by infusion (2 mg/kg/7h) thereafter. Several compartment models were applied for quantification. (−)‐ and (+)‐[18F]NCFHEB showed a twofold to threefold higher brain uptake than 2‐[18F]F‐A‐85380. All three radiotracers displayed spatially hetereogenous binding kinetics in regions with high, moderate, or low specific binding. The equilibrium of specific binding of (−)‐[18F]NCFHEB was reached earlier than that of (+)‐[18F]NCFHEB or 2‐[18F]F‐A85380. Continuous administration of the nAChR agonist A81418 inhibited the specific binding of (−)‐ and (+)‐[18F]NCFHEB but not of 2‐[18F]F‐A85380. The peripheral metabolism of (+)‐[18F]NCFHEB proceeded somewhat slower than that of the other radiotracers. Both enantiomers of [18F]NCFHEB are appropriate radiotracers for neuroimaging of nAChR in pigs. Their binding profile in vivo appears to be more selective than that of 2‐[18F]F‐A85380. (−)‐[18F]NCFHEB offers a faster equilibrium of specific binding than 2‐[18F]F‐A85380. Synapse 62:205–218, 2008. © 2007 Wiley‐Liss, Inc.
Effects of Triton X‐100 and Acyclovir on Human Serum Albumin Structure
Authors: Liu Tianqing , Guo Rong 
Published: December 2007

AbstractThe effects of acyclovir and Triton X‐100 on the behavior of human serum albumin (HSA) in a acyclovir/HSA/H2O system were studied by UV spectroscopy, fluorescence spectroscopy and polarization, conductivity, zeta potential, and circular dichroism. Both acyclovir and Triton X‐100 affect the structure and behavior of HSA. The intrinsic fluorescence intensity, net charge of HSA and the conductivity of the system increase initially with increased acyclovir concentration, and the zeta potential of HSA decreases initially. The effects of Triton X‐100 are similar to those of acyclovir except for the non‐radiant energy transfer in the quenching process of Triton X‐100 to HSA. The associating site of HSA with acyclovir is the same as that of HSA with Triton X‐100.
Deacidification of Soybean Oil Using Membrane Processing and Subcritical Carbon Dioxide
Authors: Lai Louise L. , Soheili Kambiz C. , Artz William E. 
Published: December 2007

AbstractVegetable oils have been deacidified using supercritical carbon dioxide and membrane processing. However, the pressures required are substantially greater than those used in industry. Therefore, the feasibility of using subcritical carbon dioxide (at much lower pressures) and membrane processing to separate free fatty acids (FFA) from triacylglycerols (TAGs) was examined. First, FFA/TAG solubility tests were completed (10–25 °C and 68–136 atm). The oil samples were separated using a FilmTec NF90 or a FilmTec BW30 membrane in a dead‐end type cell. Within the range examined, the greatest solubility for oleic acid was at 25 °C and 136 atm. For soybean oil TAGs, the greatest solubility was at 20 °C and 136 atm. However, for the separation of the two components, 20 °C and 68 atm was best among the condition combinations examined. The solubility of oleic acid ranged from 0.294 to 0.455 mg/mL in subcritical carbon dioxide, while the solubility of triacylglycerols ranged from 0.066 to 0.139 mg/mL. The FilmTec BW30 membrane provided significantly better separation of FFAs from TAGs than did the NF90 membrane. Both membranes were selective for oleic acid, although the BW30 had greater selectivity for oleic acid (βoleic acid = 2.12, βTAGs = 0.24) than the NF90 membrane (βoleic acid = 1.26, βTAGs = 0.81).
Anxieties in Mainland Chinese and Singapore Chinese adolescents in comparison with the American norm
Authors: Li Huijun , Ang Rebecca P. , Lee Jiyoon 
Published: December 2007

AbstractThere is a growing literature base on child and adolescent anxiety. Cross‐cultural research on child and adolescent anxiety, however, has been relatively limited. This study examined whether there were similarities and differences in the self reported anxieties in Mainland Chinese and Singapore Chinese adolescents (12–17 years of age), and whether these similarities or differences were related to gender and/or grade. This study also compared anxiety levels of Mainland Chinese and Singapore Chinese adolescents with the American normative sample (12–17 years of age). The results indicate that the levels of anxieties did not differ based on country (China and Singapore). Gender differences were evident. Gender and grade interaction effects were found on the anxiety scales. Mixed results were found when comparing Mainland Chinese and Singapore Chinese with the American normative sample on the different anxiety scales.
The influence of natural enemies on wing induction in Aphis fabae and Megoura viciae (Hemiptera: Aphididae)
Authors: Kunert G. , Schmoock-Ortlepp K. , Reissmann U. , Creutzburg S. , Weisser W.W. 
Published: December 2007

AbstractPrevious studies have shown that the aphid species, Aphis fabae Scopoli and Megoura viciae Buckton, do not produce winged offspring in the presence of natural enemies, in contrast to results for the pea aphid (Acyrthosiphon pisum (Harris)) and the cotton aphid (Aphis gossypii Glover); but these studies did not involve exposing aphids directly to natural enemies. We exposed colonies of both A. fabae and M. viciae to foraging lacewing (Chrysoperla carnea (Stephens)) larvae and found that the predators did not induce winged morphs among offspring compared to unexposed controls. Colonies of A. fabae responded to an increase in aphid density with increasing winged morph production, while such response was not found for M. viciae. We suggest that different aphid species differ in their susceptibility to natural enemy attack, as well as in their sensitivity to contact.
Comparison of five allopatric fruit fly parasitoid populations (Psyttaliaspecies) (Hymenoptera: Braconidae) from coffee fields using morphometric and molecular methods
Authors: Billah M.K. , Kimani-Njogu S.W. , Wharton R.A. , Woolley J.B. , Masiga D. 
Published: December 2007

AbstractMorphometric studies of five allopatric parasitoid populations (genusPsyttaliaWalker) from coffee plantations in Cameroon (Nkolbisson), Ghana (Tafo) and Kenya (Rurima, Ruiru and Shimba Hills) and one non-coffee population (from Muhaka, Kenya) were compared with individuals ofPsyttalia concolor(Szépligeti), a species released in several biological control programmes in the Mediterranean Region since the 20th Century. Analyses of wing vein measurements showed the second submarginal cell of the fore wing and its adjoining veins had the heaviest principal component weights and served as the main contributing variables in the diagnostic differentiation of the populations. Two populations (Rurima and Ruiru) were found to be the closest to each other and with the strongest phenetic affinity towardP.concolor(and forming one cluster). Populations from Shimba Hills (of unknown identity), Nkolbisson (P. perproximus(Silvestri)) and Tafo formed a second cluster and were separated fromP. concolor. Comparison using amplified fragment length polymorphism (AFLP) also showed the Shimba, Nkolbisson and Tafo populations forming a cluster in a dendrogram generated from their genetic distances, with the Shimba and Tafo populations placed as the most closely related species. Based on consistent morphological similarities, morphometric and ecological data coupled with the genetic evidence from AFLP data, the Shimba population is suggested as belonging to theP. perproximusgroup and, thus, represents a new occurrence record in Kenya. Our results also support earlier conclusion from cross mating data that populations from Rurima and Ruiru belong to thePsyttalia concolorspecies-group.