bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lanthanides: Complexes with Multidentate Ligands
Authors: Yang Xiaoping , Jones Richard A. , Wong Wai‐Kwok 
Published: December 2012

Abstract
The synthesis, crystal structures, and photophysical properties of 25 polynuclear lanthanide complexes and lanthanide coordination polymers based on six multidentate “salen”‐style Schiff‐base ligands are described in this chapter. Most of these lanthanide complexes exhibit interesting “multidecker,” cage‐like, or polymeric structures. In these complexes, the multidentate Schiff‐base ligands can efficiently sensitize the emissions from lanthanide ions by serving as antennas that absorb excitation light and transfer the energy to the lanthanide centers. With the lanthanide ions encapsulated by chromophoric Schiff‐base ligands and shielded from solvent molecules, which can quench the emissions of lanthanide ions, those lanthanide complexes which have multidecker and cage‐like structures show improved luminescence properties.
Lanthanides: Aryl Compounds
Authors: Cotton Simon A. 
Published: December 2012

Abstract

Simple phenyls are only known for scandium and the later lanthanides, obtained as solvates [Ln(C
6
H
5
)
3
(THF)
3
] (Ln = Ho, Er, Tm, Lu) and [La(C
6
H
5
)
3
(THF)
2
] (Ln = Lu, Sc), which have octahedral and trigonal bipyramidal structures, respectively. These appear to oligomerize on heating, thus the lanthanides do not form unsolvated molecular phenyls. The only unsolvated species are the anions [Li(THF)
4
] [Ln(2,6‐dimethylphenyl)
4
] (Ln = Yb, Lu). Monophenyls such as [Gd(C
6
H
5
)Cl
2
(THF)
4
] can be made using a deficit of phenyl lithium in the synthesis, but with very bulky aryl groups 2,6‐dimesitylphenyl (Dmp) and 2,6‐di(1‐naphthyl)phenyl (Dnp), steric effects prevent the introduction of more than one aryl in the compounds [Y(Dmp)Cl
2
(THF)
3
], [Ln(Dmp)Cl
2
(THF)
2
] (Ln = Sc, Yb), and [DnpLnCl
2
(THF)
2
] (Ln = Y, Tm, Yb), which have adopted five‐ and six‐coordinate structures.
Lanthanides: Tetravalent Inorganic
Authors: Sroor Farid M.A. , Edelmann Frank T. 
Published: December 2012

Abstract
This chapter gives an overview on the chemistry of tetravalent lanthanide compounds, especially those of tetravalent cerium. Following a brief introduction, it covers the tetrahalides, dioxides, and other lanthanides(IV) salts. Coordination compounds of cerium in the oxidation state +4 include halogeno complexes and complexes of oxo acids, β‐diketonates and related Schiff‐base complexes, as well as porphyrinates and related complexes.
Lanthanides: Molecular Magnetic Materials
Authors: Wang Bing‐Wu , Gao Song 
Published: December 2012

AbstractRare earths are important magnetic carriers in the construction of molecular magnetic materials. In this chapter, we introduce the essential concepts and magnetic properties of molecular magnetic materials containing rare earths. For weak exchange‐coupling interactions between rare earth ions and other spin carriers, only a few magnetic ordering systems are briefly described in terms of their magnetic properties and geometry structures. Considerable attention is focused on the low‐dimensional magnetic compound with slow relaxation of magnetization behavior. Quantum tunneling and the relaxation mechanism are also briefly introduced in the section on magnetic relaxation.
Lanthanides: Superconducting Materials
Authors: Dos santos‐García Antonio J. , Alario‐Franco Miguel Á. , Sáez‐Puche Regino 
Published: December 2012

AbstractSince the discovery of superconductivity in mercury by the Dutch physicist Heike Kamerlingh Onnes a century ago, in 1911, hundreds of superconducting materials including elements, intermetallic compounds, molecular and nonmolecular solids are now known. Among these, the rare earth element seems to play an important role in the synthesis and magnetic properties of the so‐called high‐temperature superconductors. In spite of the efforts made in the developing of a theory that fully explains this amazing phenomenon, there is no consensus among scientists yet. However, this fact has not represented a barrier for the developing of superconducting materials in films, wires, etc. that allows one to use them for many applications. This article is an overview and an introduction to superconductivity and superconducting materials.
Lanthanides: Homogeneous Catalysis
Authors: Yao Yingming , Nie Kun 
Published: December 2012

Abstract
Organolanthanide complexes are those compounds containing Ln‐X σ‐bonds, such as alkyls, amides, hydrides, alkoxides, and aryloxides, which readily hydrolyze when they are exposed to moist air, with the formation of the lanthanide hydroxides. The potential applications of organolanthanide complexes in homogeneous catalysis are the main driving force for the development of organolanthanide chemistry. In the past decades, organolanthanide chemistry has received a rapid development, and a variety of ligand systems including cyclopentadienyl and noncyclopentadienyl groups were developed to stabilize numerous organolanthanide complexes. Indeed, some organolanthanide complexes show exciting catalytic activity in homogeneous catalysis, both in organic synthesis and polymerization. For example, some organolanthanide complexes can efficiently catalyze organic transformations such as hydroelementations of alkenes, the amidation of aldehydes with amines, Tishchenko reaction, addition of amines to nitriles, and guanylation of carbodiimides. Organolanthanide complexes can also catalyze the polymerization of some nonpolar and polar monomers. In this chapter, the recent developments of the application of organolanthanide complexes in homogeneous catalysis are summarized.
Lanthanides: Heterogeneous Catalysis
Authors: Walrod John Hamilton , Atwood David A. 
Published: December 2012

Abstract

Rare earth oxides, which generally take the form Ln
2
O
3,
are widely used in heterogeneous catalysis. This article provides a brief description of the Ln
2
O
3
oxides, which includes a comparison of their chemical and physical properties. The basicity of heterogeneous oxides is examined, and the different pKa's on the surface are modeled. The catalytic properties of the oxides will be correlated with their various chemical and physical properties. Several different examples of their use in rare earth heterogeneous catalysis will be described including oxidative methane coupling and transesterification of triglycerides.
Lanthanides: Supramolecular Chemistry
Authors: Kitchen Jonathan A. , Gunnlaugsson Thorfinnur 
Published: December 2012

AbstractIn this chapter, some of the most recent examples of the use of lanthanide ions in the formation of functional supramolecular complexes and self‐assemblies are detailed. The examples focus mainly on the use of the lanthanides to direct the synthesis of complex structures published within the last few years, in the form of mononuclear or polynuclear complexes, where the physical properties of the lanthanides, such as their luminescent and magnetic properties, have been exploited to form functional supramolecular assemblies, e.g., luminescent‐based sensors or single molecule magnets (SMMs). The use of the lanthanides to direct the formation of complex self‐assembly architectures is an area of research that is rapidly growing in the field of lanthanide‐based supramolecular chemistry, where the coordination requirements of the lanthanides when coupled with ligand design can give rise to the formation of highly novel and structurally complex species.
Lanthanides: Amino Acid Compounds
Authors: Zheng Zhiping 
Published: December 2012

AbstractThe synthetic and structural chemistry of lanthanide complexes with α‐amino acids under low‐ and high‐pH conditions is summarized. The preparative methods, diverse coordination modes, fascinating solid‐state structures, and solution behavior of such complexes are discussed. Under acidic conditions, only the carboxylate group of the amino acid participates in the metal coordination. For those with a side‐chain carboxylate group, more extensive bridging interactions of the ligand and the lanthanide ions are identified. Under physiological or even higher‐pH conditions, both the amino and carboxylate groups, be they skeletal or present in the side chain, could be coordinating, leading to much more diverse coordination modes of these unique ligands in their lanthanide complexes. Distinct from their low‐pH counterparts, complexes obtained under higher‐pH conditions are products of lanthanide hydrolysis, limited by the supporting amino acid ligands. Presence of structurally well‐defined polynuclear lanthanide–oxo/hydroxo cluster motif is characteristic of these interesting compounds that provide fundamental insight into the lanthanide interactions with biological environment.
Lanthanides: Sensors for Lanthanides and Actinides
Authors: Vargas‐Zúñiga Gabriela I. , Sessler Jonathan L. 
Published: December 2012

AbstractIn this chapter, recent advances in the area of chemical‐based lanthanide and actinide sensing are summarized, and several representative examples of molecules that have been employed as sensors for the lanthanide and actinide ions using either optical or electrochemical monitoring (“read out”) techniques have been detailed. Because it represents an area where specific receptor design has played an instrumental role, the authors focus on detection strategies based on ion‐selective electrodes, as well as those that give rise to an easy‐to‐monitor optical response (so‐called optodes).
Lanthanides: Luminescence Applications
Authors: Andres Julien , Chauvin Anne‐Sophie 
Published: December 2012

Abstract
This chapter is an illustration of the fundamental concepts that are described elsewhere. The reader finds information regarding the visible as well as the NIR‐emitting lanthanide ions, which are illustrated by spectra and the main transitions involved. The chapter demonstrates how to characterize the color from a luminescent emission, how to define a color space, and the potential uses of lanthanide‐emitting complexes. Upconversion processes are then described, with their potential applications, followed by the principle of LASER (light amplification by stimulated emission of lanthanide radiation). A short review of some of the requirement for designing an efficient luminescent lanthanide complex is then presented, and illustrated by several families of ligands. A discussion of some of the properties of these ligands helps understanding why they have been extensively used for years in numerous applications. Some dedicated aspects are treated, such as the problem of solubility, stability, and sensing ability.
Lanthanides: Siloxides
Authors: Krempner Clemens , McNerney Brian 
Published: December 2012

AbstractThe chemistry of rare earth siloxides, also referred to as rare earth silanolates or silyloxides, is reviewed. After a brief discussion of the electronic and steric properties of various siloxide ligands, the synthetic and structural aspects of divalent, trivalent, and tetravalent rare earth siloxides are presented along with selected reactivity studies. The main focus, however, is on the chemistry of trivalent rare earth siloxides with special emphasis given to the steric and electronic influence of the siloxide ligand on the structure, stability, and reactivity on the supported rare earth metal. Applications of some heteroleptic rare earth siloxides as homogeneous catalysts in the polymerization of isoprene and hydrosilylation of olefins are included and briefly discussed.
DNA-Reparatur und Alterung
Authors: Schumacher B. 
Published: December 2012

Zusammenfassung
Die letzten Jahre haben erhebliche Fortschritte im Verständnis der Biologie des Alterns erbracht. Die Bedeutung genomischer Instabilität als kausaler Faktor der funktionellen Degeneration in der Alterung wurde besonders durch Untersuchungen an progeroiden Syndromen deutlich. Humane Progerien stellen seltene Erbkrankheiten dar, welche von ausgesprochener Diversität und Komplexität gekennzeichnet sind. Die Manifestationen progeroider Syndrome reflektieren sowohl die Funktion der involvierten DNA-Reparatur- und Schadensantwortmechanismen als auch die komplexen physiologischen Reaktionen auf DNA-Läsionen. Untersuchungen an biologischen Modellsystemen progeroider Erkrankungen haben Verbindungen zwischen der DNA-Schadensantwort und genetischen Regulationsmechanismen der Alterung aufgezeigt. Durch diese Erkenntnisse hat sich einerseits das Verständnis der Ursachen von Progerie und Alterung verbessert, andererseits werden neue Strategien erkenntlich, welche zur Entwicklung präventiver Interventionen zur Behandlung progeroider Symptome und altersbedingter Erkrankungen führen könnten.
Cockayne-Syndrom
Authors: Kamenisch Y. , Berneburg M. 
Published: December 2012

Zusammenfassung
Das Cockayne-Syndrom (CS) ist eine seltene, autosomal-rezessive Erkrankung, charakterisiert durch vorzeitige Alterungssymptomatik mit Degeneration des zentralen Nervensystems, Verlust des subkutanen Fettgewebes und Kachexie. Auslöser dieser Erkrankung sind autosomal-rezessiv vererbte Mutationen im CSA- und CSB-Gen. Im Zellkern sind das CSA- und das CSB-Protein sowohl an der DNA-Reparatur als auch der Transkription beteiligt. Außerhalb des Zellkerns schützen die CS-Proteine im Mitochondrium vor oxidativ induzierten mitochondrialen (mt) DNA-Schäden und spielen somit möglicherweise eine wichtige Rolle beim altersbedingten Verlust des subkutanen Fettgewebes. Damit ist das CS nicht nur wichtig als Modellerkrankung zur Untersuchung molekularer Mechanismen der DNA-Reparatur, sondern auch für das Verständnis der Ursachen des Alterungsprozesses.
European oak powdery mildew: impact on trees, effects of environmental factors, and potential effects of climate change
Authors: Marçais Benoit , Desprez-Loustau Marie-Laure 
Published: December 2012

Abstract
• Context

Powdery mildew is one of the most common diseases of oaks in Europe. After alarming reports in the beginning of the twentieth century following the presumed introduction of the invasive fungus, the disease has become familiar to foresters. However, its impact may vary greatly according to intrinsic and extrinsic factors.

• Aims

We aimed at providing updated and synthesised information on the impact of powdery mildew on oak and on the effects of environment on disease.

• Methods

A comprehensive literature review was performed, including old reports of the early epidemics to more recent data.

• Results

Tree growth patterns are of critical importance to explain the severity of the disease and the differences between juvenile and mature trees. A critical element, especially for infection of mature trees, is the availability of spores during the production of the first leaf flush. High disease impact is often related to modified growth patterns, either by environmental factors (insects or frost) or silvicultural practices (e.g., coppicing).

• Conclusion

Powdery mildew can have important impacts in natural oak regenerations and a significant role in decline of mature trees. Climate change might influence the disease severity mainly by altering the host pathogen phenological synchrony. Process-based models are required for reliable predictions.
Preoperative dexmedetomidine prevents tourniquet‐induced hypertension in orthopedic operation during general anesthesia
Authors: Lu Yao , Zhang Ye , Dong Chun‐Shan , Yu Jun‐Ma , Wong Gordon Tin‐Chun 
Published: December 2012

AbstractThis study was a double‐blinded randomized control trial designed to investigate the hemodynamic effects of dexmedetomidine on prolonged tourniquet inflation. Thirty‐seven patients scheduled for elective orthopedic surgery of the lower limb under general anesthesia were recruited. They were randomly assigned to receive intravenous dexmedetomidine (DEX, 0.5 μg/kg; n = 18) or normal saline (CON; n = 19) before tourniquet inflation. Arterial blood pressure and heart rate were recorded every 10 minutes until 60 minutes after the start of tourniquet inflation and again immediately after deflation. In the DEX group, arterial pressure was not significantly changed, but in the CON group arterial pressure was significantly increased at 40, 50, and 60 minutes after the start of tourniquet inflation. Development of more than 30% increase in arterial pressure during tourniquet inflation was more frequent in the CON group than in the DEX group. Preoperative intravenous dexmedetomidine could therefore prevent tourniquet‐induced hypertension in patients undergoing general anesthesia.
Dynamic Behaviors of a Circular Worktable Mounted on Closed-Type Hydrostatic Thrust Bearing Compensated by Constant Compensations
Authors: Kang Y. , Chou H.-C. , Wang Y.-P. , Chen C.-H. , Weng H. C. 
Published: December 2012

AbstractThis study investigates the influences of constant compensations which are produced by capillary or constant flow pump on the dynamic characteristics of a circular worktable supported by a closed-type hydrostatic thrust bearing. The dynamic behaviors of this worktable are analyzed by using Runge-Kutta method to solve the coupled motion equation of worktable and pressure equations of hydrostatic film flow. For various supply pressure parameters, external loads, and varieties of design parameters, the dynamic responses of worktable subjected to both external excitations of harmonic force and step force are simulated, respectively. The results reveal the influences of both constant compensations on the dynamic characteristics of hydrostatic bearing by the different responses of worktable and make the appropriate parameters of design can be found for the worktable-bearing system. The accomplishments of this study will help the designers who deal with the hydrostatic- bearing compensated by constant restrictions to select the design parameters to approach the optimum condition.
SURVIVING CRISIS: INSIGHTS FROM NEW EXCAVATION AT KARPHI, 2008
Authors: Wallace Saro , Mylona Dimitra 
Published: December 2012

Seventy years after its first investigation, Karphi (Karfi) on Crete was the subject of a new pilot excavation in 2008. The main aim was to provide the first up-to-date detailed contextual records for the site across a representative area, thus filling in interpretative gaps left by the original extensive excavation. This paper presents and analyses these records with the aim of investigating the likely complexity of social systems at one of the largest new communities founded in Crete after the collapse of Bronze Age statesc.1200bc. Recent research has tended to focus on small villages, or on sites which later developed into poleis, meaning that crisis-period remains are poorly preserved. Occupied only between the crisis horizon ofc.1200bcand an important nucleation of Cretan communities at large ‘proto-polis’ settlements occurring in the early tenth century, the large Karphi site offers insight into the special challenges of creating large, potentially diverse new communities in crisis circumstances. It has one of the most dramatic of the new settlement locations, on steep-sided peaks 1100 m above sea level in an area which had never previously been settled. The social and economic adjustments needed here were particularly sharp and urgent, and the paper examines the structures which enabled them, using preliminary analyses of bioarchaeological data from the new project to assist reconstruction of the economy. The site has had other, highly specialised uses in its history, on which the new excavation has thrown light. The results highlight not only the resonance of this landscape in ancient consciousness, but also the ways in which such resonance could be exploited, both in the socially volatile post-collapse period and in the context of enhanced social and economic complexity as polis states started to come into being. Finally, a first set of radiocarbon dates from the new excavation is presented and assessed with regard to the dating of the Cretan Bronze to Iron Age transition and its wider ramifications.
‘Id est, crux Christi’: tracing the Old English Motif of the Celestial Rood
Authors: Hawk Brandon W. 
Published: December 2012

AbstractThe celestial cross is a prominent motif in Old English texts, and, rather than deriving from a single specific source, the figure provides a case study with implications for understanding the variety of backgrounds that often contribute to Anglo-Saxon conceptions of specific literary images. Tracing the development of the motif from its early Christian origins to its role in Anglo-Saxon England reveals a persistent correlation to eschatology, the importance of the liturgy in its dissemination, and a complex matrix of associations that must be accounted for in considering the Old English settings in which the image exists. An examination of these literary settings further helps to interpret the ways in which Anglo-Saxon authors used this matrix of associations for the celestial cross in their conceptions of the Judgement Day.
A more permanent homeland: land tenure in Guthlac A
Authors: Clark Stephanie 
Published: December 2012

AbstractTo a greater extent than other saints' lives, Guthlac A is a poem about a land dispute. Through contextualizing the central ‘battle for the beorg’ within Anglo-Saxon practices of land tenure, this article shows that Guthlac A represents the spiritual conflict between Guthlac and the devils as a land dispute between unworthy tenants who have been given temporary tenure of the land and a warrior of God who is granted permanent tenure as his reward for faithful service. By portraying the devils' loss of the beorg and Guthlac's acquisition of it through the framework of Anglo-Saxon customs of land-holding, the poem dramatizes replacement doctrine, the teaching that the number of the saved would equal the number of fallen angels and replace them in the heavenly kingdom.
Mortality improvement by socio-economic circumstances in England (1982 to 2006)
Authors: Lu J. L. C. , Wong W. , Bajekal M. 
Published: December 2012

AbstractAssessing longevity risk is crucial to the financial management of annuities and longevity-related financial instruments. Actuaries have been using socio-economic circumstances (SEC) of individuals estimated through postcodes, pension size and occupation to price annuities for prospective customers. Differences in mortality rates of people in different SEC have been discussed extensively but less is known about how their mortality rates have changed over time.A lack of regular, consistent and credible mortality data for people in different SEC has hampered the study of historical mortality trends. This in turn has made forecasting a greater challenge. To address some of these data issues, we have obtained mortality and population data between 1981 and 2007 for England, divided into SEC quintiles (measured by the relative deprivation of the area of residence according to the Index of Multiple Deprivation (IMD) 2007). Using the data, we have analysed the mortality trends by SEC. These findings can provide insight into mortality improvement for people in different SEC. This can contribute to commercial decisions for annuity businesses, reinsurance and longevity swaps.