bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single‐crystalline photochromism of diarylethene dimers bridged by a spiro structure
Authors: Kobatake Seiya , Kuma Shunpei , Irie Masahiro 
Published: May 2007

AbstractNew types of diarylethene dimers bridged by a spiro structure were synthesized. One of their dimers formed three kinds of polymorphic forms by recrystallization from different solvents: hexane (1a‐α), acetone (1a‐β), and acetonitrile (1a‐γ). In crystals of 1a‐α and 1a‐β the molecules are packed in solvent‐free crystal structures, whereas crystal 1a‐γ includes acetonitrile molecules in the crystal. The difference of significant photochromic reactivities in their polymorphic crystals was observed for photocoloration reactions. Crystals 1a‐β and 1a‐γ showed photochromism in the single‐crystal phase, but 1a‐α did not do so. Their photochromic reactivity was found to depend on the distance between the reactive carbon atoms by X‐ray crystallographic analysis. When the distance is less than 4.2 Å in the antiparallel conformation, the molecule can undergo photochromism in the crystal. On the other hand, crystals of bromo‐substituted diarylethene dimer (2a) cannot be suitable for X‐ray crystallographic analysis when it was recrystallized from hexane, acetone, and acetonitrile. However, it formed single crystal by recrystallization from p‐xylene, which showed photochromism in the crystalline phase. The edge‐to‐face aromatic interaction between p‐xylene molecules assisted the crystal growth of the diarylethene dimer. Upon irradiation with ultraviolet light, two kinds of the enantiomers, (M,SS)‐ and (P,RR)‐2b, are produced. Partial photobleaching reactions of either of the two enantiomers by irradiation with linearly polarized visible light were confirmed by polarized absorption spectroscopy. Copyright © 2007 John Wiley & Sons, Ltd.
Phototriggered release of photolabile drugs via two‐photon absorption‐induced cleavage of polymer‐bound dicoumarin
Authors: Härtner Sebastian , Kim Hee‐Cheol , Hampp Norbert 
Published: May 2007

Abstract7‐(tert‐Butyldimethylsiloxy)‐7′‐(methacryloxy)dicoumarin (TBS‐Cum‐D‐MA) is introduced as a versatile polymerizable and photocleavable linker system for drug attachment to acrylic polymers. Following the copolymerization of the TBS‐Cum‐D‐MA with monomeric methylmethacrylate, a model drug chlorambucil was attached in a simple reaction. Phototriggered drug release via single‐ and two‐photon absorption induced cycloreversion of the cyclobutane of the dicoumarin part was investigated. The bound drug chlorambucil is sensitive to UV light being required for single‐photon induced cleavage of the dicoumarin linker and decomposes upon UV exposure. However, under the conditions of two‐photon absorption induced drug release, no photodegradation of chlorambucil was observed. As the only effective two‐photon absorber in the molecule is the cyclobutane structure, even high energies of visible light do not cause any degradation of the drug. This suggests that two‐photon‐triggered drug release may be successfully accomplished even with UV light sensitive drugs. The concept introduced here may be a powerful strategy in polymer design for photocontrolled drug delivery devices. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2443–2452, 2007
New sulfur‐centered radicals as photopolymerization initiating species
Authors: Lalevée Jacques , Zadoina Lacramioara , Allonas Xavier , Fouassier Jean Pierre 
Published: May 2007

AbstractNew thiols and disulfides are proposed as radical polymerization photoinitiators or coinitiators. The drawback of the bad smell is strongly limited for the proposed compounds. Among the systems investigated, the disulfides photosensitized by isopropylthioxanthone and the tetrazole‐derived thiols in the presence of benzophenone, camphorquinone, or isopropylthioxanthone have been found to be highly reactive and, in some cases, even better than a reference type I or type II photoinitiator. These thiols can also be incorporated into a combination of chloro‐hexaaryl bisimidazole (Cl‐HABI) and a photosensitizer, such as a coumarin or ketocoumarin. Interestingly, a photosensitizer/Cl‐HABI/tetrazolethiol derivative system exhibits a higher reactivity than a commonly used photosensitizer/Cl‐HABI/N‐phenylglycine system. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2494–2502, 2007
Chitosan‐graft‐poly(ϵ‐caprolactone)s: An optimized chemical approach leading to a controllable structure and enhanced properties
Authors: Guan Xipeng , Quan Daping , Shuai Xintao , Liao Kairong , Mai Kancheng 
Published: May 2007

AbstractA novel synthetic approach was developed for the controllable modification of chitosan (CS) with poly(ϵ‐caprolactone) (PCL). 6‐O‐Triphenylmethyl‐chitosan (TMCS) was synthesized as a highly soluble intermediate in organic solvents to facilitate an efficient grafting reaction of PCL onto CS in a homogeneous reaction medium. Subsequently, the syntheses of CS‐g‐PCL copolymers with different degrees of substitution (ds) and various chain lengths of PCL (number‐average molecular weight = 1200–11,000) were carried out by a coupling reaction between the carboxylic terminal groups of PCL chains and the amino groups of TMCS. The successful grafting reaction was confirmed by GPC measurements, which indicated that the products were graft copolymers rather than physical blends. The ds, defined as the number of PCL chains per saccharide unit, of the graft copolymers could be adjusted simply by changes in the molar feed ratios of PCL to CS, and graft copolymers with different ds values ranging from 0.28 to 0.49 were synthesized, as calculated by 1H NMR and elemental analysis. DSC and X‐ray measurements showed that the melting temperature and enthalpy of the PCL grafts of these graft copolymers could be adjusted by the ds and the chains length of PCL, respectively. Meanwhile, the CS‐g‐PCL copolymers exhibited better solubility in various solvents, such as in chloroform for some of the resultant graft copolymers, than the original CS. Finally, nanoparticles of 100–200 nm, having hydrophobic PCL domains and cationic hydrophilic surfaces, were obtained through the self‐assembly of the copolymers in selective solvents. These types of graft copolymers have great potential in various applications, such as targeted drug and gene delivery as well as tissue engineering. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2556–2568, 2007
Circadian phase entrainment via nonlinear model predictive control
Authors: Bagheri N. , Stelling J. , Doyle F.J. 
Published: May 2007

AbstractA nonlinear model predictive control algorithm is developed to investigate the phase‐resetting properties of robust nonlinear biological oscillators; in particular, those of the circadian rhythm. This pacemaker is an autonomous biochemical oscillator with a free‐running period close to 24 h. Research in chronobiology indicates that light stimuli may delay or advance the phase of the oscillator, allowing it to synchronize physiological processes and entrain to the environment. In this paper, a closed‐loop optimal phase tracking control algorithm is developed and applied to a mammalian circadian model. The integration of MPC‐based light pulses, coupled with environmental light:dark cycles, allows the circadian system to recover phase differences within 1.5 days—a fraction of the natural open‐loop simulated mammalian recovery time. Accelerated phase entrainment may alleviate disorders caused by circadian rhythms that are out of phase with the environment, and improve performance. Copyright © 2007 John Wiley & Sons, Ltd.
Sample size calculation for the Wilcoxon–Mann–Whitney test adjusting for ties
Authors: Zhao Yan D. , Rahardja Dewi , Qu Yongming 
Published: May 2007

AbstractIn this paper we study sample size calculation methods for the asymptotic Wilcoxon–Mann–Whitney test for data with or without ties. The existing methods are applicable either to data with ties or to data without ties but not to both cases. While the existing methods developed for data without ties perform well, the methods developed for data with ties have limitations in that they are either applicable to proportional odds alternatives or have computational difficulties. We propose a new method which has a closed‐form formula and therefore is very easy to calculate. In addition, the new method can be applied to both data with or without ties. Simulations have demonstrated that the new sample size formula performs very well as the corresponding actual powers are close to the nominal powers. Copyright © 2007 John Wiley & Sons, Ltd.
Multifunctionalized Polymer Microcapsules: Novel Tools for Biological and Pharmacological Applications
Authors: Sukhorukov Gleb B. , Rogach Andrey L. , Garstka Malgorzata , Springer Sebastian , Parak Wolfgang J. , Muñoz‐Javier Almudena , Kreft Oliver , Skirtach Andre G. , Susha Andrei S. , Ramaye Yannic , Palankar Raghavendra , Winterhalter Mathias 
Published: May 2007

AbstractWe describe recent developments with multifunctional nanoengineered polymer capsules. In addition to their obvious use as a delivery system, multifunctional nanocontainers find wide application in enzymatic catalysis, controlled release, and directed drug delivery in medicine. The multifunctionality is provided by the following components: 1) Luminescent semiconductor nanocrystals (quantum dots) that facilitate imaging and identification of different capsules, 2) superparamagnetic nanoparticles that allow manipulation of the capsules in a magnetic field, 3) surface coatings, which target the capsules to desired cells, 4) metallic nanoparticles in the capsule wall that act as an absorbing antenna for electromagnetic fields and provide heat for controlled release, and 5) enzymes and pharmaceutical agents that allow specific reactions. The unique advantage of multifunctional microcapsules in comparison to other systems is that they can be simultaneously loaded/functionalized with the above components, allowing for the combination of their properties in a single object.
Formalizing the interference temperature model
Authors: Clancy T. Charles 
Published: May 2007

AbstractTo combat recent spectral overcrowding in unlicensed bands, the FCC has been investigating new ways to manage RF resources. The idea is to let people use licensed frequencies, provided they can guarantee interference perceived by the primary license holders will be minimal. With advances in software and cognitive radio, practical ways of doing this are on the horizon. In 2003, the FCC released a memorandum seeking comment on the interference temperature model (ITM) for controlling spectrum use. Formally defining and analyzing techniques for implementing this model are the primary goals of this paper.Two interpretations of the ITM are developed and for each, we examine tradeoffs between power, bandwidth, and capacity. From these relationships, algorithms for computing RF transmission parameters are developed. These algorithms seek to maximize both capacity and spectral efficiency for a given RF environment. Additionally, we describe ways to choose a center frequency that will optimize future performance, subject to the constraints of the ITM. Copyright © 2007 John Wiley & Sons, Ltd.
CULTURE AND CHRONOLOGY IN AFRICAN HISTORY
Authors: PETERSON DEREK R. 
Published: May 2007

Sources and methods in African history: spoken, written, unearthed. Edited by T. Falola and C. Jennings. Rochester: University of Rochester Press, 2004. Pp. xxi+409. ISBN 1-58046-140-9. £50.00.Honour in African history. By John Iliffe. Cambridge: Cambridge University Press, 2005. Pp. xv+404. ISBN 0-521-54685-0. £16.99.Black experience and the empire. Edited by P. Morgan and S. Hawkins. Oxford: Oxford University Press, 2004. Pp. xv+416. ISBN 0-19-926029-x. £39.00. Muslim societies in African history. By D. Robinson. Cambridge: Cambridge University Press, 2004. Pp. xx+220. ISBN 0-521-533566-x. £10.99.The study of African culture stands in a uneasy relationship with the study of African history. Historians work by pegging people, places, and events to a place on time's ever-lengthening yardstick. For the historical discipline, time is a structure that stands behind and lends meaning to human events. Culture, by contrast, is often claimed to be timeless, the unique inheritance of a distinct group of people. Culture builders work by short-circuiting chronology. They poach events, names, clothing styles, and other inspirational elements from the past and marshal them as a tradition to be proud of. The study of cultural history enters into a field where the partitions between past and present are being trampled by the traffic of human imagination.
HAYDN’S MELANCHOLY VOICE: LOST DIALECTICS IN HIS LATE CHAMBER MUSIC AND ENGLISH SONGS
Authors: NOVEMBER NANCY 
Published: May 2007

AbstractFrom the nineteenth century onwards the stereotype of Haydn as cheerful and jesting has dominated the reception of his music. This study contributes to the recent scholarship that broadens this view, with a new approach: I set works by Haydn in the context of eighteenth-century ideas about melancholy, those of Edmund Burke, Francisco Goya, Henry Home (Lord Kames), Immanuel Kant and Johann Georg Zimmermann. Their conceptions of melancholy were dialectical, involving the interplay of such elements as pleasure and pain, freedom and fettering, and self-reflection and absorption. I consider the relevance of these dialectics to Haydn’s English songs, his dramatic cantata Arianna a Naxos and two late chamber works. Musical melancholy arises, I argue, when the protagonist of a work – be it the vocal character in a song or the ‘composer’s voice’ in an instrumental work – exhibits an ironic distance from his or her own pain. The musical dialectics in these works prompt listeners, for their part, to take a step back to contemplate the borders and limits of emotional experience and communication.
Persistent voids: a new structural metric for membrane fusion
Authors: Kasson Peter M. , Zomorodian Afra , Park Sanghyun , Singhal Nina , Guibas Leonidas J. , Pande Vijay S. 
Published: May 2007

AbstractMotivation: Membrane fusion constitutes a key stage in cellular processes such as synaptic neurotransmission and infection by enveloped viruses. Current experimental assays for fusion have thus far been unable to resolve early fusion events in fine structural detail. We have previously used molecular dynamics simulations to develop mechanistic models of fusion by small lipid vesicles. Here, we introduce a novel structural measurement of vesicle topology and fusion geometry: persistent voids.Results: Persistent voids calculations enable systematic measurement of structural changes in vesicle fusion by assessing fusion stalk widths. They also constitute a generally applicable technique for assessing lipid topological change. We use persistent voids to compute dynamic relationships between hemifusion neck widening and formation of a full fusion pore in our simulation data. We predict that a tightly coordinated process of hemifusion neck expansion and pore formation is responsible for the rapid vesicle fusion mechanism, while isolated enlargement of the hemifusion diaphragm leads to the formation of a metastable hemifused intermediate. These findings suggest that rapid fusion between small vesicles proceeds via a small hemifusion diaphragm rather than a fully expanded one.Availability: Software available upon request pending public release.Contact: kasson@cmgm.stanford-edu or pande@stanford.eduSupplementary information: Supplementary data are available on Bioinformatics online.
Seed-borne Fungi Detected in Sugar Beet Seeds Imported into India during Last Three Decades
Authors: Agarwal P. C. , Dev Usha , Rani Indra , Khetarpal R. K. 
Published: May 2007

Quarantine processing of 1,111 samples of germplasm and inbred lines of sugar beet seed imported into India from 1976 to 2005 resulted in the interception of 10 pathogenic fungi including Uromyces beticola, the beet rust pathogen which is not yet reported from India. Other seed-borne fungi of high economic significance that were detected included Colletotrichum dematium, Fusarium solani, Pleospora betae, and Verticillium albo-atrum as well as other fungal pathogens for which sugar beet is a non-host crop, such as Drechslera halodes, D. rostrata, D. sorokiniana, Cephalosporium sp., and Pestalotia sp. Various fungi detected in sugar beet seed imported from different countries are presented and their economic significance is discussed. Seeds contaminated with U. beticola were disinfected by dipping them in concentrated sulphuric acid for 1 min while those infected with P. betae were disinfected by hot water treatment at 50°C for 30 min. Accepted for publication 8 September 2006. Published 11 December 2006.
Penicillium expansum Invades Apples Through Stems during Controlled Atmosphere Storage
Authors: Rosenberger David A. , Engle Catherine A. , Meyer Frederick W. , Watkins Christopher B. 
Published: May 2007

Empire apples were collected from six orchards in 1997 and 1998 and were then subjected to various inoculation and storage regimes to determine how non-wounded fruit become infected with Penicillium expansum and to determine if decay susceptibility varies with orchard source. Replicated samples of fruit were inoculated within 24 h of harvest either by placing a 10 μl droplet containing 500 conidia of P. expansum onto the end of the apple stems or by placing 500 μl containing 10,000 conidia into the stem basin. Fruit were stored for 7 to 9 months either in cold air (1.1°C) or in controlled-atmosphere (CA) storage (1.1°C, 1.6% oxygen and 2.2% carbon dioxide), and were then evaluated for decay. Twenty-seven to 47% of fruit that had been inoculated by placing spores on the ends of stems developed decay during CA storage whereas less than 1% of similarly inoculated fruit decayed during cold-air storage. Placing spore suspension into the stem basins also resulted in less than 1% decay. Orchard-to-orchard variation in incidence of decay that developed was positively correlated with boron concentrations in both apple leaves (R2 = 0.66) and apple fruit (R2 = 0.62). This is the first report of P. expansum causing commercial losses in apples due to invasion through stems and also the first Accepted for publication 28 September 2006. Published 13 December 2006.
Evaluation of Pathogenicity of Bipolaris and Curvularia spp. on Dwarf and Ultradwarf Bermudagrasses in Florida
Authors: Brecht Matthew O. , Stiles Carol M. , Datnoff Lawrence E. 
Published: May 2007

Isolates of Curvularia lunata, C. geniculata, Bipolaris hawaiiensis, and B. cynodontis were tested for pathogenicity on the hybrid bermudagrass cultivars Tifdwarf, TifEagle, and FloraDwarf at 20 and 30°C. Curvularia lunata, C. geniculata, and B. hawaiiensis produced some minor leaf tip necrosis at the cut ends of leaves 24 to 48 h after inoculation. Bipolaris cynodontis produced significant tip dieback and leaf spotting on all three cultivars at both 20 and 30°C, and disease severity was higher at 20°C than at 30°C. With C. lunata, C. geniculata, and B. hawaiiensis, occasional leaf-spotting occurred only on senescing, older leaves. Bipolaris cynodontis is considered pathogenic on bermudagrasses, while C. lunata, C. geniculata, and B. hawaiiensis are considered senectopathic, able to incite disease only in senescing plant tissue. Curvularia lunata and B. hawaiiensis resulted in higher disease severity at 30°C than at 20°C, indicating that these species are senectopathic at higher temperatures. Accepted for publication 29 September 2006. Published 19 January 2007.
On-Farm Trial Assessing Efficacy of Three Insecticide Classes for Management of Stink Bug and Fruit Damage on Processing Tomatoes
Authors: Cullen Eileen M. , Zalom Frank G. 
Published: May 2007

Five foliar insecticides representing a neonicotinoid (thiamethoxam), a pyrethroid (lambda-cyhalothrin), a neonicotinoid plus pyrethroid (thiamethoxam and lambda-cyhalothrin), and two organophosphates (dimethoate and methamidophos, respectively) were evaluated for relative efficacy in managing consperse stink bug (Euschistus conspersus Uhler) on California processing tomatoes. E. conspersus density and percentage fruit damage were measured at harvest in an on-farm experiment at two locations in 2002, and small plot experiments in 2002 and 2003. Results showed that thiamethoxam plus lambda-cyhalothrin, lambda-cyhalothrin, and methamidophos can provide equivalent control of E. conspersus on processing tomatoes. Relative efficacy of the same treatments was inconsistent when applied before completion of small nymph development as estimated by the E. conspersus phenology model. Results can be utilized by growers with canning contracts that limit total organophosphate active ingredient per season, or in cases where stink bug treatment thresholds are reached within the processor preharvest interval for organophosphates. Insecticide efficacy evaluation is discussed within the context of continued research to provide IPM-compatible insecticide options to growers facing low processor tolerance for stink bug damaged fruit, and organophosphate insecticide restrictions in tomato canning contracts. Accepted for publication 22 November 2006. Published 23 March 2007.
Detection of Candidatus Liberibacter asiaticus from Wampee (Clausena lansium Skeels) by Nested PCR
Authors: Deng Xiaoling , Zhou Gen , Li Huaping , Chen Jianchi , Civerolo Edwin L. 
Published: May 2007

Wampee (Clausena lansium Skeels) is native to southern China and Southeast Asia. Wampee trees are attractive, with grape-like fruits and a muscat taste and are popular in home gardens. Like other members of Rutaceae, wampee has long been suspected to have yellow shoot disease or Huanglongbing (HLB) and Diaphorina citri, the disease vector, was capable of a long-term survival on Wampee. The authors recommend that eradication of wampee trees surrounding citrus orchards should be part of the overall management of citrus HLB. Accepted for publication 20 December 2007. Published 19 April 2007.
Increasing Outbreaks and Impact of Iris yellow spot virus in Bulb and Seed Onion Crops in the Imperial and Antelope Valleys of California
Authors: Poole Grant J. , Pappu Hanu R. , Davis Richard M. , Turini Thomas A. 
Published: May 2007

Outbreaks of IYSV were first observed in May 2003 in two Imperial County onion seed fields. In August, 2005, symptomatic onion plants were widespread in four fields in the Antelope Valley, Los Angeles County, CA. IYSV infection was confirmed by ELISA and RT-PCR. This was the first known recording of IYSV in Antelope Valley. Increasing incidence and impact of IYSV in a major onion-growing area highlights the need for research into developing managing options for this important disease of onion. Accepted for publication 22 January 2007. Published 8 May 2007.
Occurrence of Begomovirus Associated with Yellow Vein Mosaic Disease of Kenaf (Hibiscus cannabinus) in Northern India
Authors: Ghosh Raju , Paul Sujay , Roy Anirban , Mir Javid Iqbal , Ghosh S. K. , Srivastava R. K. , Yadav U. S. 
Published: May 2007

The occurrence, distribution, and disease incidence of yellow vein mosaic (YVM) disease of kenaf (Hibiscus cannabinus) in northern India are reported. The disease was found in both commercial and experimental farms in the Bahraich district, Uttar Pradesh, India and caused significant reduction in plant height and crop yield. Southern hybridization with begomovirus-specific probe and PCR amplification with DNA β and coat protein primers confirmed the association of begomovirus with the disease. Accepted for publication 25 January 2007. Published 8 May 2007.