bluuebunny/crossref_metadata_2025 huggingface dataset:
Conservation of forest-dwelling arthropod species: simultaneous management of many small and heterogeneous risks
Authors: Spence John R. , Langor David W. , Jacobs Joshua M. , Work Timothy T. , Volney W. Jan A.
Published: April 2009

The Canadian insect fauna is too inadequately understood to support well-informed assessments about its conservation status; however, the foregoing collection of synthetic papers illustrates potential threats from industrial forestry. Loss of forest species and dramatic changes in forest insect assemblages driven by forestry activities are well illustrated by studies from places where industrial forest management has been more intensive or of longer duration. Improved understanding of how arthropod species are coupled to habitats, especially microhabitats, appears to be central to progress toward their conservation. Studies of arthropods conducted at the species level are most relevant for applied conservation purposes, because only species-level work that is well documented with voucher specimens provides adequate comparative data to document faunal change. Although taxonomic infrastructure required to support such work is seriously under-resourced in Canada, entomologists can help themselves by producing useful modern resources for species identification, by undertaking collaborative biodiversity work that minimizes the split between taxonomists and ecologists, and by supporting incentives for work at the species level. Securing the future of arthropod diversity in Canadian forests through effective policy will require sound regionally defined bases for whole-fauna conservation that mesh with broader land-use planning. Building these will require a practical understanding of how “ecosite”-classification systems relate to arthropod diversity, accurate inventories of the predisturbance forest fauna in all regions, and development of sound monitoring plans designed to both detect faunal change efficiently and identify its drivers. Such monitoring plans should include both baseline inventories and monitoring of designated control areas. In addition, effective biomonitoring efforts will facilitate the development of suites of arthropod indicators, accommodate both seasonal (especially phenological) and annual variation, clarify the relationship between cost-effective samples and reality, and ensure adequate consideration of “rare” species. Return on investment in monitoring will depend on effective preplanned linkage to policy development that can respond to drivers of faunal change in a way that effectively addresses undesired changes.
Structure and conservation of lepidopteran communities in managed forests of northeastern North America: a review
Authors: Summerville Keith S. , Crist Thomas O.
Published: April 2009

We review the existing literature on patterns of moth (Lepidoptera) species richness and community composition in northeastern Nearctic forest ecosystems across hierarchical scales ranging from individual trees to entire managed ecoregions. Moths are species-rich in northeastern forests of North America, with the most diverse families being Noctuidae and Geometridae. Individual trees and forest stands, however, are often dominated by few species. Climate, stand age, disturbance regime, and landscape heterogeneity are significant predictors of abundance of dominant species. Most other moth species in the regional pool are patchily distributed and appear to occur regularly at very low abundance. Moth communities respond predictably to forest-management practices, and the outcomes of postmanagement response are largely driven by changes in the plant community. Significant reductions in moth species richness and changes in community composition are correlated with clear-cut harvesting, whereas selective logging appears to cause more moderate changes in moth community structure. Broad-scale effects of forest fragmentation on moth communities in unglaciated regions are best described by species replacement rather than species loss; moth species richness decreases slightly across a gradient of fragment sizes, but shifts in moth community composition are more important, especially in the relative importance of herbaceous-plant-feeding species in large and small fragments. Species that appear to be most sensitive to timber management or habitat loss are dietary specialists as larvae, dispersal-limited as adults, or dependent on commercially valuable tree species such as oaks,QuercusL. (Fagaceae). Restored forest stands tend to converge in terms of lepidopteran species dominance and diversity among stands, suggesting that the long-term consequences of timber management or habitat loss include a significant reduction of regional β-diversity. Finally, future research on forest Lepidoptera should include an emphasis on understanding the role of urban woodland habitat in retaining viable and diverse moth communities and how the spatial pattern of timber harvest affects the relative magnitude of α- and β-diversity components within a given ecoregion.
Evaluation of carabid beetles as indicators of forest change in Canada
Authors: Work Timothy T. , Koivula Matti , Klimaszewski Jan , Langor David , Spence John , Sweeney Jon , Hébert Christian
Published: April 2009

Our objective was to assess the potential of carabid beetles (Coleoptera: Carabidae) as effective bioindicators of the effects of forest management at a Canadian national scale. We present a comparison of carabid beetle assemblages reported from large-scale studies across Canada. Based on the initial response following disturbance treatment, we found that carabid assemblages consistently responded to disturbance, but responses of individual species and changes in species composition were nested within the context of regional geography and finer scale differences among forest ecosystems. We also explored the relationship between rare and dominant taxa and species characteristics as they relate to dispersal capacity and use of within-stand habitat features such as coarse woody debris. We found no relationship between life-history characteristics (such as body size, wing morphology, or reported associations with downed wood) and the relative abundance or frequency of occurrence of species. Our results suggest that carabids are better suited to finer scale evaluations of the effects of forest management than to regional or national monitoring programs. We also discuss several knowledge gaps that currently limit the full potential of using carabids as bioindicators.
Winged morph of the high arctic aphid Acyrthosiphon svalbardicum (Hemiptera: Aphididae): abundance, reproductive status, and ecological significance
Authors: Simon J.-C. , Bonhomme J. , Blackman R.L. , Hullé M.
Published: April 2009

The aphid Acyrthosiphon svalbardicum Heikinheimo, which is endemic to Svalbard and feeds exclusively on eightpetal mountain-avens, Dryas octopetala L. (Rosaceae), has developed a series of adaptive traits to cope with the harsh conditions of the High Arctic. Prior to this study, only a single specimen of the winged morph of A. svalbardicum had been found, suggesting extremely low dispersal potential. In 2006 we collected many winged females in several places at Kongsfjorden, Spitsbergen. Although winged individuals were generally found in high-density populations, no significant relationship existed between aphid abundance and wing development. We discuss whether this sudden increase in winged-morph production by A. svalbardicum is related to a warmer than usual summer in Svalbard.
Chaoborus sampseran. sp., a new chaoborid (Diptera: Culicomorpha: Chaoboridae) from Papua Province, Indonesia
Authors: Ogawa Joshua R. , Judd Darlene D.
Published: April 2009

A new species,Chaoborus sampsera,is described from male and female adults collected from Papua Province in western New Guinea, Indonesia. Based on leg banding, wing pigmentation, and possession of a median paramere sclerite in males, the new species belongs to theChaoborus“pallidus” group of Colless.Chaoborus sampserais distinguished from other species of the “pallidus” group by the scimitar-shaped parameres. Although relationships among theseChaoborusspecies are unclear, there are morphological characters that support the “pallidus” group.
Molecular cloning, characterization, and expression analysis of a QM homologue in the ant Polyrhachis vicina (Hymenoptera: Formicidae)
Authors: Lü Shumin , Xi Gengsi , Wang Xiaohui
Published: April 2009

QM, a tumor-suppressor gene, plays an important role in cell growth, differentiation, and apoptosis. In this report, a homologue of human QM was isolated from the ant Polyrhachis vicina Roger. The full-length cDNA of P. vicina QM (PvQM) is 827 base pairs (bp) and contains a 5′-untranslated region of 91 bp and a 3′-untranslated region of 77 bp. The open reading frame of PvQM encodes a deduced 219-amino acid peptide with a predicted molecular mass of 25.1 kilodaltons. The results of sequence alignments indicate that the PvQM protein shares an overall identity of 76.7%–98.2% with other known QM homologues, and is most closely related to that of Apis mellifera L. (Hymenoptera: Apidae). Real-time quantitative reverse transcription - polymerase chain reaction was performed to compare PvQM mRNA expression during P. vicina development and within different castes. The data revealed that PvQM mRNA is differentially expressed during P. vicina development, with the highest expression level in embryos and the lowest in late-instar larvae and pupae. The levels of PvQM transcripts also vary among castes, with higher levels in workers and lower levels in both males and females. These results suggest that PvQM is developmentally and caste-specifically regulated at the level of transcription.
Slow or stepped rewarming after acute low-temperature exposure does not improve survival ofDrosophila melanogasterlarvae
Authors: Sinclair Brent J. , Rajamohan Arun
Published: April 2009

We tested the hypothesis that slow rewarming would improve the ability ofDrosophila melanogasterMeigen (Diptera: Drosophilidae) larvae to survive acute low-temperature exposure. Four larval stages (1st, 2nd, and 3rd instars, including wandering-stage 3rd instars) of four wild-type strains were exposed to –7 °C for periods of time expected to result in 90% mortality. Larvae were then directly transferred to their rearing temperature (21 °C) or returned to this temperature either in a stepwise fashion (pausing at 0 and 15 °C) or by slow warming at 1 or 0.1 °C/min. We observed a reduced rapid cold-hardening effect and no general increase in survival of acute chilling in larvae rewarmed in a stepwise or slow fashion, and we hypothesize that slow rewarming may result in accumulation of chill injuries.
Potential of bigleaf lupine for building and sustainingOsmia lignariapopulations for pollination of apple
Authors: Sheffield Cory S. , Westby Sue M. , Smith Robert F. , Kevan Peter G.
Published: April 2009

Bees of the genusOsmiaPanzer (Hymenoptera: Megachilidae) are among the contenders to replace honey bees,Apis melliferaL. (Apidae), for pollinating tree-fruit crops. One species,Osmia lignariaSay, has shown great potential in western North America and was recently introduced into Nova Scotia for evaluation as a pollinator of apple,MalusMill. (Rosaceae). A major component of that study was to develop management options forO. lignaria, including methods of sustaining nesting females following crop flowering to maximize population recovery for pollination in subsequent seasons. The objective of this study was to evaluate bigleaf lupine,Lupinus polyphyllusLindl. (Fabaceae), as a secondary food plant for nesting femaleO. lignariaby investigating nesting activity, pollen-use patterns, and fecundity. During 2002–2003, femaleO. lignariacollected high proportions of apple pollen (>70%) during mid and late flowering; after then, most pollen (>90%) was collected from bigleaf lupine. The flowering period of lupine in Nova Scotia (late May to early July) slightly overlapped that of apple, so there was no scarcity of pollen resources during the life-span ofO. lignaria. Most nests typically showed high levels (≤200%) of population growth, but recorded levels varied among nest types and locations. In 2004, nests closer to lupine plots exhibited significantly greater population recovery than nests located farther away (i.e., approximately 600 m). Bigleaf lupine is a suitable plant species for meeting the pollen requirements of nesting populations ofO. lignariafollowing apple flowering, thus promoting the recovery of populations to meet apple pollination requirements in subsequent seasons.
Ecological applications of pheromone trapping ofMalacosoma disstriaandChoristoneura conflictana
Authors: Jones Brad C. , Evenden Maya L.
Published: April 2009

The forest tent caterpillar,Malacosoma disstriaHübner (Lepidoptera: Lasiocampidae), and large aspen tortrix,Choristoneura conflictana(Walker) (Lepidoptera: Tortricidae), are important pests of trembling aspen,Populus tremuloidesMichx. (Salicaceae), in western Canada. Populations of both species can be monitored with sex pheromone-baited traps as part of an integrated pest management program. Moths captured in pheromone traps can also be used for ecological studies. Captured males of each species were examined to test the effect of population density, geographic region, and collection date on moth quality. Moth quality was assessed on the basis of wing area and level of infection with microsporidian parasites. The level of microsporidian infection ofM. disstriawas strongly dependent on geographic region but not on population density. MaleM. disstriafrom high-density populations had smaller wings than males from endemic populations. Wing area of maleM. disstriadecreased throughout the flight period. Neither collection date nor microsporidian infection level affected wing area of maleC. conflictana.Collection date also did not affect the level of microsporidian infection ofC. conflictana. These data support pheromone trapping as a tool to detect microsporidian infections and examine their temporal and density-dependent effects on wing size inM. disstriaandC. conflictanapopulations.
Systematics and ecology of Anachipteria geminus sp. nov. (Acari: Oribatida: Achipteriidae) from arboreal lichens in western North America
Authors: Lindo Zoë , Clayton Marilyn , Behan-Pelletier Valerie M.
Published: April 2009

We present the systematics and ecology of a new species of arboreal oribatid mite in the family Achipteriidae, Anachipteria geminussp. nov., a dominant arthropod in canopy lichens associated with western hemlock (Tsuga heterophylla (Raf.) Sarg. (Pinaceae)) and Pacific silver fir (Abies amabilis (Dougl. ex Loud.) Dougl. ex Forbes (Pinaceae)) in the coniferous temperate and montane forests of the Pacific Northwest of North America. The species is described on the basis of the morphology of all active instars plus molecular sequence data for the D3 region of the 28s rRNA (D3-28s) and mitochondrial cytochrome oxidase 1 (CO1) genes. Anachipteria geminus is the dominant oribatid mite in foliose lichens in the upper canopies of Pacific montane conifer trees. Specimens were found in 100% of canopy lichens sampled, and abundances can reach 1450 individuals / 100 g dry mass of lichen. Analysis of the population structure indicates that A. geminus has seasonally stable populations consistent with overlapping generations. Anachipteria geminus expresses morphological character states that require expanding the diagnoses of the genus Anachipteria and the family Achipteriidae. A revised diagnosis and morphological key to species of Anachipteria in Canada are given.
Comparison of adult emergence of wheat stem sawfly from material overwintered in the field and the laboratory
Authors: Delaney Kevin J. , Perez-Mendoza Joel , Weaver David K.
Published: April 2009

We examined whether collection time (pre-winter vs. post-winter) influenced adult and female emergence success and body mass of wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), from four Montana populations in 2005-2006. Adult emergence was generally higher from post-harvest material in post-winter collections but varied widely among populations. No significant effect of collection time on male-biased adult emergence from post-harvest residue collected near Conrad (37% vs. 31%) was detected, although adult emergence was greater for post-winter collection than for pre-winter collections from sites near Havre (90% vs. 81%), near Amsterdam (88% vs. 41%), and near Loring (67% vs. 0%); these three populations had a bias towards adult females that exceeded 2:1. Adult body mass was greater for post-winter-collected males (30% higher) and females (15%) only from near Amsterdam. Diapausing C. cinctus larvae overwintering under field conditions had better adult emergence, and spring collection is recommended in order to minimize time allocated to acquiring C. cinctus populations for research.
Effect of ultrasound on acetylcholinesterase activity inHelicoverpa armigera(Lepidoptera: Noctuidae)
Authors: Zha Yu-Ping , Xu Fen , Chen Qi-Cai , Lei Chao-Liang
Published: April 2009

It is well known that noctuid moths respond to ultrasound frequencies produced by insectivorous bats performing a series of evasive maneuvers such as loops, dives, rolls, and turns. Certain ultrasound frequencies may be considered an environmental stress factor for these moths, causing physiological and behavioral effects. We investigated changes in acetylcholinesterase activity ofHelicoverpa armigera(Hübner) exposed to ultrasound produced from a commercial device (LHC20). Our results indicated that stress effects on acetylcholinesterase activity resulting from exposure to ultrasound do not differ according to sex, but effects on different developmental stages ofH. armigeradiffer significantly depending on duration of exposure.Enzyme activity increased in adults after 20 min exposure to ultrasound and decreased in pupae after 30 and 50 min exposure. Enzyme activity in larvae was reduced after 20 min and increased after 40 and 60 min. The results of this study also indicate that stress caused by exposure to ultrasound could modulate the cholinergic system inH. armigera.
Two non-destructive techniques for determining the sex of live adult Hylobius warreni
Authors: Öhrn Petter , Klingenberg Matthew , Hopkins Gareth , Björklund Niklas
Published: April 2009

Two non-destructive sexing techniques suitable for use in the field and laboratory are described, and tested with the Warren root collar weevil, Hylobius warreni Wood (Coleoptera: Curculionidae). On the second visible abdominal sternite of males is a longitudinal depression that is absent on females. In addition, setae on the last visible abdominal sternite of females are arranged longitudinally; setae on males are arranged radially. For the first character, accuracy was 90% and sex could be determined without the aid of magnification. The latter character was slightly more reliable, at 95% accuracy, but required at least 12× magnification.
A new species and taxonomic notes on northern Nearctic Cerodontha(Icteromyza) (Diptera: Agromyzidae)
Authors: Boucher Stéphanie
Published: April 2009

Cerodontha(Icteromyza)pilosan. sp.is described from the Yukon Territory. The Palaearctic speciesC.(I.)lineella(Zetterstedt) is recorded for the first time in North America, based on specimens from northern Canada and Alaska, andC.(I.)pollinosa(Melander) is synonymized withC. lineella.Cerodontha pilosais most similar toC.(I.)longipennis(Loew) andC.(I.)lineella. Distinguishing characters and a modification of Spencer’s key to Canadian species ofCerodonthaare given to separate these species.
Prevalence of four species of egg parasitoids attacking tabanid eggs in Manitoba, Canada
Authors: Iranpour Mohmood , Galloway Terry D.
Published: April 2009

Egg masses of the horse fly, Hybomitra nitidifrons nuda (McDunnough), and the deer fly, Chrysops aestuans Wulp (Diptera: Tabanidae), were collected during the summers of 1996–2000 from five different locations in southern Manitoba. On average, hymenopterous egg parasitoids were reared from more than 90% of collected egg masses. Telenomus hybomitrae Iranpour and Galloway and (or) Telenomus utilis Iranpour and Galloway (Hymenoptera: Platygastridae: Telenominae) emerged from multilayered egg masses of H. n. nuda. However, Trichogramma semblidis (Aurivillius) (Hymenoptera: Trichogrammatidae) and (or) Telenomus chrysopsis Iranpour and Galloway were reared from single-layered egg masses of C. aestuans. In H. n. nuda egg masses, more than 33% of individual eggs were parasitized and more than an additional 35% were apparently damaged by the two telenomine parasitoids. In C. aestuans egg masses, approximately 40% of individual eggs were parasitized and 18% produced neither parasitoids nor larvae.
One‐Pot Preparation of Polymer–Enzyme–Metallic Nanoparticle Composite Films for High‐Performance Biosensing of Glucose and Galactose
Authors: Fu Yingchun , Li Penghao , Xie Qingji , Xu Xiahong , Lei Lihong , Chen Chao , Zou Can , Deng Wenfang , Yao Shouzhuo
Published: April 2009

New polymer–enzyme–metallic nanoparticle composite films with a high‐load and a high‐activity of immobilized enzymes and obvious electrocatalysis/nano‐enhancement effects for biosensing of glucose and galactose are designed and prepared by a one‐pot chemical pre‐synthesis/electropolymerization (CPSE) protocol. Dopamine (DA) as a reductant and a monomer, glucose oxidase (GOx) or galactose oxidase (GaOx) as the enzyme, and HAuCl4 or H2PtCl6 as an oxidant to trigger DA polymerization and the source of metallic nanoparticles, are mixed to yield polymeric bionanocomposites (PBNCs), which are then anchored on the electrode by electropolymerization of the remaining DA monomer. The prepared PBNC material has good biocompatibility, a highly uniform dispersion of the nanoparticles with a narrow size distribution, and high load/activity of the immobilized enzymes, as verified by transmission/scanning electron microscopy and electrochemical quartz crystal microbalance. The thus‐prepared enzyme electrodes show a largely improved amperometric biosensing performance, e.g., a very high detection sensitivity (99 or 129 µA cm−2 mM−1 for glucose for Pt PBNCs on bare or platinized Au), a sub‐micromolar limit of detection for glucose, and an excellent durability, in comparison with those based on conventional procedures. Also, the PBNC‐based enzyme electrodes work well in the second‐generation biosensing mode. The proposed one‐pot CPSE protocol may be extended to the preparation of many other functionalized PBNCs for wide applications.
Beam to String Transition of Vibrating Carbon Nanotubes Under Axial Tension
Authors: Wei Xianlong , Chen Qing , Xu Shengyong , Peng Lianmao , Zuo Jianmin
Published: April 2009

State‐of‐the‐art nanoelectromechanical systems have been demonstrated in recent years using carbon nanotube (CNT) based devices, where the vibration of CNTs is tuned by tension induced through external electrical fields. However, the vibration properties of CNTs under axial tension have not been quantitatively determined in experiments. Here, a novel in situ method for precise and simultaneous measurement of the resonance frequency, the axial tension applied to individual CNTs and the tube geometry is demonstrated. A gradual beam‐to‐string transition from multi‐walled CNTs to single‐walled CNTs is observed with the crossover from bending rigidity dominant regime to extensional rigidity dominant regime occur much larger than that expected by previous theoretical work. Both the tube resonance frequency under tension and transition of vibration behavior from beam to string are surprisingly well fitted by the continuum beam theory. In the limit of a string, the vibration of a CNT is independent of its own stiffness, and a force sensitivity as large as 0.25 MHz (pN)−1 is demonstrated using a 2.2 nm diameter single‐walled CNT. These results will allow for the designs of CNT resonators with tailored properties.
Contributions of A. Roberto Frisancho to human population biology: An introduction
Authors: Leonard William R.
Published: April 2009

Over the span of his career, A. Roberto Frisancho has been one of the prime architects of the development and expansion of human population biology. His research and scholarly publications have helped to move the field beyond simple descriptions of human variation to address the nature and evolutionary origins of human biological diversity. Frisancho's early work in the Peruvian Andes elegantly demonstrated the importance of developmental acclimatization for promoting adaptive responses to the multiple stressors of high‐altitude environments. Since mid‐1970s, he has played a major role in developing and expanding the use of anthropometric techniques for assessing physical growth and nutritional status. Frisancho's influential publications have helped to make the use of anthropometric methods commonplace in the fields of nutritional science and public health. Throughout his career, Frisancho's work has examined how environmental, genetic, and developmental factors interact to influence human health and nutritional status. His research has addressed topics ranging from the determinants of low‐birth weight infants in teenage mothers to the origins of obesity and associated metabolic diseases in populations of the developing world. Both the breadth and impact of Frisancho's work have been truly remarkable. The field of human population biology owes much to the tremendous contributions of A. Roberto Frisancho. Am. J. Hum. Biol., 2009. © 2009 Wiley‐Liss, Inc.
Reproduction and lifespan: Trade‐offs, overall energy budgets, intergenerational costs, and costs neglected by research
Authors: Jasienska Grazyna
Published: April 2009

In human females allocation of resources to support reproduction may cause their insufficient supply to other metabolic functions, resulting in compromised physiology, increased risks of diseases and, consequently, reduced lifespan. While many studies on both historical and contemporary populations show that women with high fertility indeed have shorter lifespans. This relationship is far from universal: a lack of correlation between fertility and lifespan, or even an increased lifespan of women with high fertility have also been documented. Reduced lifespan in women with high fertility may be undetectable due to methodological weaknesses of research or it may be truly absent, and its absence may be explained from biological principles. I will discuss the following reasons for a lack of the negative relationship, described in some demographic studies, between the number of children and lifespan in women: (1) Number of children is only a proxy of the total costs of reproduction and the cost of breastfeeding is often higher than the pregnancy cost but is often not taken into account. (2) Costs of reproduction can be interpreted in a meaningful way only when they are analyzed in relation to the overall energy budget of the woman. (3) Trade‐offs between risks of different diseases due to reproduction yield different mortality predictions depending on the socio‐economic status of the studied populations. (4) Costs of reproduction are related not only to having children but also to having grandchildren. Such intergenerational costs should be included in analysis of trade‐offs between costs of reproduction and longevity. Am. J. Hum. Biol., 2009. © 2009 Wiley‐Liss, Inc.
Morphological abnormalities in children with thyroidal congenital hypothyroidism
Authors: Kempers Marlies J.E. , Ozgen Heval M. , Vulsma Thomas , Merks Johannes H. , Zwinderman Koos H. , de Vijlder Jan J.M. , Hennekam Raoul C.M.
Published: April 2009

Several groups of investigators have reported an increased incidence of congenital anomalies in patients with congenital hypothyroidism. Furthermore, in patients with congenital hypothyroidism and mutations in genes known to be involved in thyroid development, specific extra‐thyroidal abnormalities have been observed. The goal of the present study was to gain insight in the types and patterns of morphological characteristics depending on the type of congenital hypothyroidism of thyroidal origin (CH‐T). In 242 Dutch CH‐T patients with a thyroid agenesis, a dystopic thyroid rudiment or a eutopic thyroid gland, we performed a careful physical examination of the body surface directed to visually detectable morphological abnormalities; results were compared to a group of 1,007 Dutch control subjects. The percentage of patients with one or more major abnormalities in the total CH‐T cohort (33.1%) and in patients with CH‐T dystopic thyroid (37.2%) was significantly higher than in the control population (21.8%; P < 0.001). Especially in the CH‐T dystopic thyroid group specific major malformations (bilateral ear pits; oligodontia) were found more frequently. Also, the percentage of patients in the total CH‐T group with one or more minor anomalies (96.3%) was significantly higher than in the control group (82.5%). The careful grouping of patients according to their CH‐T etiology and the types and patterns in morphological findings may be helpful in the search for novel genes involved in thyroid development. © 2009 Wiley‐Liss, Inc.
Zweiphotonenabsorption und das Design von Zweiphotonenfarbstoffen
Authors: Pawlicki Miłosz , Collins Hazel A. , Denning Robert G. , Anderson Harry L.
Published: April 2009

Zwei Photonen sind besser als eines – dieser Grundsatz gilt für einen großen Bereich von Anwendungen von den Ingenieurwissenschaften bis hin zur Physiologie. Durch Fortschritte beim Verständnis des Phänomens der Zweiphotonenabsorption und bei der Entwicklung von Zweiphotonenfarbstoffen gewinnt das Forschungsgebiet schnell an Bedeutung.

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Gegenüber der herkömmlichen Einphotonenabsorption bietet die Zweiphotonenabsorption etliche Vorteile, die zu Anwendungen in der Mikroskopie und Mikrofabrikation, der optischen Leistungsbegrenzung, in Upconversion‐Lasern und dreidimensionalen Datenspeichern, der photodynamischen Therapie und der lokalisierten Freisetzung biologisch aktiver Spezies geführt haben. Diese Anwendungen haben wiederum die Entwicklung neuartiger Farbstoffe mit großen Zweiphotonenabsorptionsquerschnitten vorangetrieben. Dieser Aufsatz beginnt mit den theoretischen Grundlagen der Zweiphotonenabsorption, stellt die Vielfalt möglicher Anwendungen vor und beschreibt erste Struktur‐Eigenschafts‐Beziehungen, die als Leitlinien bei der Entwicklung effizienter Zweiphotonenfarbstoffe dienen können.
Innentitelbild: Intermolecular Methoxycarbonylation of Terminal Alkynes Catalyzed by Palladium(II) Bis(oxazoline) Complexes (Angew. Chem. 18/2009)
Authors: Kato Keisuke , Motodate Satoshi , Mochida Tomoyuki , Kobayashi Takuya , Akita Hiroyuki
Published: April 2009

Ein Bisoxazolin‐Ligand erhöht die Präferenz von PdII für π‐Systeme. Die direkte Umwandlung von terminalen Alkinen in β‐Methoxyacrylate mit Komplexen solcher Bisoxazolin(box)‐Liganden wird von K. Kato und Mitarbeitern in der Zuschrift auf S. 3376 ff. beschrieben. Dichtefunktionalrechnungen belegen, dass die π‐Orbitale des Liganden in [Pd(box)(TFA)2] über die Doppelbindungen und die Peripherie delokalisiert sind und energetisch nahe dem LUMO liegen. Die Reaktion kann auch in einer Synthese von Kawain genutzt werden.

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Two‐Photon Absorption and the Design of Two‐Photon Dyes
Authors: Pawlicki Miłosz , Collins Hazel A. , Denning Robert G. , Anderson Harry L.
Published: April 2009

Two photons are better than one: This principle applies to a wide range of applications, ranging from engineering to physiology. Recent advances in our understanding of the phenomenon of two‐photon absorption (see picture) and in the design of two‐photon dyes are rapidly increasing the scope of this field.

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Two‐photon absorption has important advantages over conventional one‐photon absorption, which has led to applications in microscopy, microfabrication, three‐dimensional data storage, optical power limiting, up‐converted lasing, photodynamic therapy, and for the localized release of bio‐active species. These applications have generated a demand for new dyes with high two‐photon absorption cross‐sections. This Review introduces the theory of two‐photon absorption, surveys the wide range of potential applications, and highlights emerging structure–property correlations that can serve as guidelines for the development of efficient two‐photon dyes.
Cover Picture: Direct CH Metalation with Chromium(II) and Iron(II): Transition‐Metal Host / Benzenediide Guest Magnetic Inverse‐Crown Complexes (Angew. Chem. Int. Ed. 18/2009)
Authors: Alborés Pablo , Carrella Luca M. , Clegg William , García‐Álvarez Pablo , Kennedy Alan R. , Klett Jan , Mulvey Robert E. , Rentschler Eva , Russo Luca
Published: April 2009

Chromation and ferration are the latest additions to the concept of alkali‐metal‐mediated metalation, as described by J. Klett, R. E. Mulvey, and co‐workers in their Communication on page 3317 ff. While the more electropositive sodium is essential for the reaction, it is the less electropositive chromium or iron that actually performs deprotonation of benzene. This novel reactivity can be likened to a game of chess in which the queen (Na) holds the king in check, while the knight (Cr, Fe) scores checkm(etal)ate.

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Thermal and mechanical modification of LDPE in single‐screw extruder
Authors: Ono Kazuya , Yamaguchi Masayuki
Published: April 2009

The effect of processing history in a single‐screw extruder on molecular characteristics was studied by employing commercially available low‐density polyethylene with no additives. Generation of long‐chain branch, which is responsible for the neck‐in phenomenon and draw resonance, is indicated by nonlinear viscoelastic properties of the extruded samples. Consequently, the processed samples show higher level of elastic property than the original pellet. However, thermal analysis revealed that there is no change in the distribution of short‐chain branch. Moreover, both chain scission and cross‐linking take place, and the chain scission is predominant above 320°C. Furthermore, processing history at low temperature depresses the melt elastic nature, although primary molecular structure is unchanged. This would be attributed to shear modification phenomenon. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Study of PET/PP/TiO2 microfibrillar‐structured composites, part 1: Preparation, morphology, and dynamic mechanical analysis of fibrillized blends
Authors: Li Wenjing , Schlarb Alois K. , Evstatiev Michael
Published: April 2009

The objective of this study was to manufacture and investigate a novel microfibrillar‐reinforced material based on fibrillized blends of polyethyleneterephthalate (PET), polypropylene (PP), and TiO2 nanoparticles (300 nm and 15 nm in size). The uncompatibilized and compatibilized blends (polypropylene grafted maleic anhydride as compatibilizer) were extruded and subsequently cold‐drawn into strands with a draw ratio of 10. The effects of compatibilizer and TiO2 particles on the structure and properties of drawn strands were investigated. Upon addition of compatibilizer, the preferential location of TiO2 particles shifted from the PET‐dispersed phase to the PP matrix, which brought about different structures of the drawn strands. Differential scanning calorimetry study provided indications for a heterogeneous nucleation effect of the PET fibrils on the PP matrix and of the TiO2 particles on the PET fibrils. Dynamic mechanical analysis demonstrated that the mechanical properties of the drawn strands are strongly dependent on the strand structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Vibrational dynamics of poly(L‐glutamine)
Authors: La'Verne Sanjeev John , Srivastava Shweta , Srivastava Seema , Gupta V. D.
Published: April 2009

In the present paper, we report the Fourier transform infra‐red (FTIR) spectra and an analysis of the normal modes and their dispersion, based on the calculations for an infinite chain and Urey Bradley force field with nonbonded interactions. The results thus obtained agree well with the FTIR spectra. The heat capacity obtained from the dispersion curves via density‐of‐states is in very good agreement with the experimental measurements between 50 and 500 K. We observed that the main contribution to heat capacity comes from the modes involving the coupling of the backbone skeletal and side‐chain motions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Polypropylene nanocomposite using maleated PP and diamine
Authors: Ku Kwang Hoi , Kim Sung Chul
Published: April 2009

The insertion of the aliphatic diamine inside the organoclay will help the dispersion of the clay platelets in the PP/clay nanocomposite due to the reaction between the maleated PP and the diamine. Cloisite®20A was just simply mixed with hexamethylene diamine (HMDA) under shearing condition in Brabender mixer. HMDA group was successfully penetrated into silicate layers. As a result of penetration, d‐spacing of organoclay was increased. Polypropylene/clay nanocomposites were prepared by compounding with maleated PP and amine‐treated clay. From the FTIR spectra, reaction between amine group and maleic‐anhydride group was confirmed. The effect of the organoclay on the properties of the nanocomposite such as the morphology, dynamic mechanical properties, crystal structure and crystallization behavior, glass transition temperature, thermal stability, and tensile properties were investigated and analyzed. Nanocomposites with amine‐treated clays show enhanced properties compared with those with non–amine‐treated clay (Cloisite®20A). From the TEM analysis, nanocomposites with amine‐treated clays shows better dispersibility compared with those with Cloisite®20A alone. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Organosoluble poly(ether imide)s from phthalimidine based and trifluoromethyl substituted bis(ether amine)
Authors: Sen Suman Kumar , Maji Samarendra , Dasgupta Barnali , Chatterjee Shyambo , Banerjee Susanta
Published: April 2009

A series of new organosoluble and optically transparent poly(ether imide)s (PEIs) were synthesized by the polycondensation of trifluoromethyl substituted and phthalimidine cardo group based bis(ether amine), 3,3‐bis‐[4‐{2′‐trifluoromethyl 4′‐(4″‐aminophenyl)phenoxy}phenyl]‐2‐phenyl‐2, 3‐dihydro‐isoindole‐1‐one with different fluorinated and non‐fluorinated aromatic dianhydrides (2a–e). All the PEIs were well characterized by elemental analysis, NMR, FTIR spectroscopy, and gel permeation chromatography (GPC). The synthesized PEIs showed moderate to high inherent viscosity 0.41–0.61 dL/g and excellent solubility at room temperature in different organic solvents. All the transparent yellow films showed cut‐off length upto 425 nm. They exhibited high tensile strengths upto 98 MPa, excellent thermostability upto 554°C for 5% weight loss, high glass transition temperature upto 327°C, and water uptake value less than 0.6%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Hydrogenated natural rubber blends: Aspect on thermal stability and oxidative behavior
Authors: Hinchiranan N. , Lertweerasirikun W. , Poonsawad W. , Rempel G. L. , Prasassarakich P.
Published: April 2009

Hydrogenated natural rubber (HNR) prepared from natural rubber (NR) is a new sustainable elastomer with excellent thermal properties. This study reports on the effect of vulcanization system and blend ratio on the thermal and oxidative resistance of HNR/NR vulcanizates. The various HNR/NR ratios vulcanized by peroxide and sulfur donor system exhibited the highest retention of tensile strength after thermal aging due to the formation of zinc‐dimethyldithiocarbamate (ZDMDC) which is an efficient antioxidant. The results from thermogravimetric analysis (TGA) indicated that the saturated structure of HNR had higher decomposition temperature and activation energy to enhance the thermal stability of HNR/NR vulcanizates. The initial and maximum decomposition temperatures of NR and HNR phases in vulcanizates were not affected by rubber blend ratio. This suggests that the decomposition pattern of HNR has no influence on another constituent. The increase in HNR content in the blends could retard the ozonolysis resulting in the surface cracking attacked by ozone. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A novel microencapsulation of neem (Azadirachta Indica A. Juss.) seed oil (NSO) in polyelectrolyte complex of κ‐carrageenan and chitosan
Authors: Devi Nirmala , Maji T. K.
Published: April 2009

Microcapsules containing neem (Azadirachta Indica A. Juss.) seed oil (NSO) were prepared by encapsulation of natural liquid pesticide NSO in a polyelectrolyte complex of κ‐carrageenan and chitosan. The optimum ratio between carrageenan and chitosan to form a stable polyelectrolyte complex was found as 1 : 0.36. The microencapsulation method for NSO loading was also optimized. SEM study demonstrated that the surface of the microcapsules became more irregular as oil loading increased. The release rates of NSO were studied by varying the percentage of oil loading, concentration of cross‐linking agent, and polymer concentration. Fourier transform infrared spectroscopy (FTIR) study confirmed the complex formation between κ‐carrageenan and chitosan. Differential scanning calorimetry (DSC) and FTIR study indicated the absence of any significant interaction between polyelectrolyte complex of κ‐carrageenan ‐chitosan and NSO. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of polymer glycols on micro‐aggregation structure and mechanical properties of spherulite size graded polyurethane elastomers
Authors: Kongpun Teerin , Kojio Ken , Furukawa Mutsuhisa
Published: April 2009

Spherulite size graded polyurethane elastomers (PUEs) were prepared using a mold with a temperature gradient from different polymer glycols, 4,4′‐diphenylmethane diisocyanate (MDI) and a mixture of 1,4‐butanediol (BD), and 1,1,1‐trimethylol propane (TMP) as a curing agent by a prepolymer method. The used polymer glyocols were poly(oxytetramethylene)glycol (PTMG, Mn = 2000), poly(ethylene adipate)glycol (PEA, Mn = 2000), and poly(hexamethylene adipate)glycol (PHA, Mn = 2000). The effect of polyether and polyester glycols and the temperature gradient on the micro‐aggregation structure and mechanical properties were studied by polarized optical microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, micro‐hardness test, pulsed nuclear magnetic resonance spectroscopy, and tensile test. The prepared PUEs had spherulite size graded super‐structure. Spherulite sizes of the PUEs depended significantly on the temperature gradient of the mold. Spherulite of the PUEs in contact with the mold at low temperature was significantly smaller and more dense than that contacting the mold at high temperature. The spherulite diameter of PTMG‐, PEA‐, and PHA–PUEs changed from 12.6 to 16.3 μm, 8.4 to 15.6 μm, and 10.4 to 16.0 μm, respectively from the lower temperature side (LTS) toward the higher temperature side. In contrast, the number of spherulites became sparser toward the higher one. The glass transition temperature (Tg) of PTMG‐, PEA‐, and PHA‐based PUEs elevated from −55.3°C, −19.0°C and −33.8°C at the LTS to −48.6°C, −17.8°C and −32.8°C at the HTS, respectively. Tg of all PUEs exhibited elevation from the LTS toward the higher one. This result associated with the strong microphase separation of the LTS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and properties of liquid polycarbosilanes with hyperbranched structures
Authors: Huang Muhe , Fang Yunhui , Li Ran , Huang Tianhua , Yu Zhaoju , Xia Haiping
Published: April 2009

Liquid polycarbosilanes substituted by unsaturated groups were prepared by a one‐pot synthesis with Cl2Si(CH3)CH2Cl, Cl3SiCH2Cl, and CH2CHCH2Cl (or HCCMgBr) as the starting materials. The as‐received polycarbosilanes were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance and were confirmed to have hyperbranched structures. The polymer yield, SiH content, side reaction, unsaturated group content, and polymer structure are affected by the amount of the starting materials in feed. The thermal properties of the polycarbosilanes were investigated by thermogarvimetric analysis. The ceramic yield of allyhydridopolycarbosilane is about 60% and that of ethynylhydridopolycarbosilane is over 75%, indicating that the liquid polycarbosilanes have great potential to be promising precursors to SiC. Moreover, the compositions of the polycarbosilanes and the final ceramics can be tailored by controlling the amount of the starting materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A stable porous superhydrophobic high‐density polyethylene surface prepared by adding ethanol in humid atmosphere
Authors: Yuan Zhiqing , Chen Hong , Tang Jianxin , Zhao Dejian
Published: April 2009

A stable porous superhydrophobic high‐density polyethylene (HDPE) surface with water contact angle of 160.0 ± 1.9° and sliding angle of 2.0 ± 1.6° was obtained by adding ethanol in humid atmosphere at 5°C. Soaked in water with temperatures ranging from 5 to 50°C for 15 days, even suffering compressive forces, and the water contact angles were still higher than 150°. After water flowed through the surface continuously for 30 min, even water droplets with a diameter of 4 mm dropped onto the HDPE surface from 30 cm high for 10 min, the water contact angles were also higher than 150°. A brief explanation to the formation of the porous superhydrophobic HDPE surface was put forward. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Viscoelastic behavior of rubber under a complex loading
Authors: Suphadon N. , Thomas A. G. , Busfield J. J. C.
Published: April 2009

In the literature, the loss factor of an elastomer, expressed as tan δ, has been reported to decrease with strain. This has been interpreted as a lowering of the internal viscosity due to chain orientation under strain. This contrasts with experimental findings showing that up to large strains, loss modulus does not change with strain. These experiments show that, as measured, tan δ does decrease with strain. However, a simple analysis shows that this effect is due to geometric changes alone and that the essential viscoelastic behavior, expressed as the loss modulus, is constant with strain up to an extension of about 2 for the simple unfilled compounds investigated here. This article also shows that the prestrain does not induce any significant anisotropy in the loss modulus, at least up to an extension ratio of 2. This was measured by the stretching of a rubber sample by simple extension and then the subjection of the sample to free vibrations in either torsion or tension. By the measurement of the damping in this way, the anisotropy induced by the pre‐extension was measured. The experiments in this work were all conducted on unfilled natural rubber or styrene–butadiene rubber compounds, with 2 different natural rubber compounds being used to investigate the effect of the crosslink density. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation, morphologies, and properties of positively charged quaternized poly(phthalazinone ether sulfone ketone) nanofiltration membranes
Authors: Yan Chun , Zhang Shouhai , Liu Cheng , Yang Daling , Yang Fajie , Jian Xigao
Published: April 2009

Positively charged quaternized poly(phthalazinone ether sulfone ketone) (QAPPESK) nanofiltration (NF) membranes were prepared from chloromethylated poly(phthalazinone ether sulfone ketone) by the dye/wet phase inversion method with N‐methyl‐2‐pyrrolidone (NMP) and N,N‐dimethylacetamide (DMAc) as solvents. The effects of the ratio of NMP to DMAc, the evaporation time, the evaporation temperature, and the coagulation temperature on membrane performance were evaluated by the orthogonal design method. The results showed that the optimal preparation conditions were an NMP/DMAc ratio of 2/8, an evaporation time of 5 min at 70°C, and a coagulation temperature lower than 5°C. The effects of the additive type and concentration on the QAPPESK NF membrane cross‐section morphology and performance were investigated in detail. Furthermore, QAPPESK NF membranes exhibited good thermal stability with stable membrane performance for 120 h at 60°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009