bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the 1990 Centers for Disease Control and Prevention Smoke-Free Policy
Authors: Emont Seth L. , Zahniser S. Christine , Marcus Stephen E. , Trontell Anne E. , Mills Sherry , Frazier Emma L. , Waller Michael N. , Giovino Gary A.
Published: December 2011

Purpose.

To determine the prevalence of tobacco use among Centers for Disease Control and Prevention (CDC)/Agency for Toxic Substances and Disease Registry (ATSDR) employees and the effect of the smoke-free policy on smoking behavior and air quality at work.

Design.

A stratified telephone survey of 1181 CDC/ATSDR employees randomly selected from employee rosters.

Setting.

CDC/ATSDR work sites in Atlanta, Georgia, and other major CDC locations throughout the United States and Puerto Rico.

Subjects.

Randomly selected employees of CDC/ATSDR1, or about 22% of the total CDC/ATSDR population; 98% of eligible persons selected agreed to participate.

Measures.

Demographic and smoking history variables, attitudes toward and impact of the smoke-free policy on smoking behavior, and self-report changes in air quality were the measures used.

Results.

Overall cigarette smoking prevalence was only 11.1%. One percent reported using chewing tobacco, 1.1% reported smoking a pipe, and 1.4% reported smoking cigars. Average self-reported, daily cigarette comsumption significantly decreased after the smoking ban took effect. Overall, 90 % of the employees supported the smoke-free policy, and 80 % of the employees believed that smokers were complying with the smoke-free policy. Most employees believed that the air quality of work areas and nonwork areas (65% and 69%, respectively) had improved since the smoke-free policy was implemented.

Conclusions.

These findings are consistent with previous evaluations of smoke-free policies and suggest that most employees are generally supportive of workplace smoking restrictions. Such policies can also have a positive impact on smoking behavior and perceived air quality.
Behavioral and Cognitive-Behavioral Treatments for Youth with Social Phobia
Authors: Scharfstein Lindsay , Beidel Deborah C.
Published: December 2011

Pediatric social phobia (SP) is characterized by a pervasive pattern of social timidity. SP is most often diagnosed in mid- to- late adolescence, affecting approximately 3–5% of youth. This article reviews behavioral (BT) and cognitive-behavioral treatments (CBT) for youth with SP and outlines several limitations in the current literature. Although these treatments are all presumed to be efficacious for youth with SP and are often the treatment of choice, examination of outcome often occurs in samples with mixed anxiety disorders (AD) (including generalized anxiety disorder and separation anxiety disorder). Outcome is often assessed without considering diagnostic status, obfuscating important treatment distinctions. Further, SP often accounts for only a small portion of the samples in controlled treatment trials that include different diagnostic categories. When outcomes are examined by diagnosis, recovery rates for SP often are lower in comparison with other ADs, suggesting that factors unique to SP youth are not being adequately addressed with some forms of CBT. In contrast, interventions that include social skills training result in outcome rates for SP that are equivalent to the overall rates for BT/CBT for mixed diagnostic groups. The critical role of assessment and treatment of skills deficits in youth with SP is highlighted.
Biased Self-Perception of Social Skills in Anxious Children: The Role of State Anxiety
Authors: Dodd Helen F. , Hudson Jennifer L. , Lyneham Heidi J. , Wuthrich Viviana M. , Morris Talia , Monier Laurie
Published: December 2011

The role of state and trait anxiety on observer ratings of social skill and negatively biased self-perception of social skill was examined. Participants were aged between 7 and 13 years (M = 9.65; SD = 1.77; N = 102), 47 had a current anxiety diagnosis and 55 were non-anxious controls. Participants were randomly allocated to a high or low anxiety condition and asked to complete social tasks. Task instructions were adjusted across conditions to manipulate participants' state anxiety. Observers rated anxious participants as having poorer social skills than non-anxious controls but there was no evidence that anxious participants exhibited a negative self-perception bias, relative to controls. However, as participants' ratings of state anxiety increased, their perception of their performance became more negatively biased. The results suggest that anxious children may exhibit real impairments in social skill and that high levels of state anxiety can lead to biased judgements of social skills in anxious and non-anxious children.
Effects of Age and Anxiety on Processing Threat Cues in Healthy Children
Authors: Reinholdt-Dunne M. L. , Mogg K. , Esbjorn B. H. , Bradley B. P.
Published: December 2011

This study investigated relationships between childhood anxiety, chronological age, and threat processing biases. It used a cross-sectional design comparing younger and older children, separated using a median-split on trait anxiety scores into low-anxious versus moderately-anxious groups. Participants were 67 schoolchildren, aged 7–14 years, who completed emotional Stroop and visual probe tasks with angry, happy, and neutral faces. Results from both tasks showed (i) a main effect of age on emotion processing, i.e., increased bias for emotional relative to neutral faces in younger than older children, and (ii) a moderating effect of age on anxiety-related bias for threat. That is, on the modified Stroop task, an enhanced processing bias for angry faces, relative to neutral faces, was found only in the group of moderately-anxious younger children. This bias appeared to be specific to angry faces, as it was not found for happy faces. On the visual probe task, moderately-anxious younger children also showed an enhanced attentional bias for angry faces, relative to neutral faces; in addition, they also showed a similar bias for happy relative to neutral faces. Taken together, findings suggest that moderately-anxious younger children show enhanced processing of threat, relative to neutral information, and that this anxiety-related threat bias lessens with age.
The 2009–2010 arctic stratospheric winter – general evolution, mountain waves and predictability of an operational weather forecast model
Authors: Dörnbrack A. , Pitts M. C. , Poole L. R. , Orsolini Y. J. , Nishii K. , Nakamura H.
Published: December 2011

Abstract. The relatively warm 2009–2010 Arctic winter was an exceptional one as the North Atlantic Oscillation index attained persistent extreme negative values. Here, selected aspects of the Arctic stratosphere during this winter inspired by the analysis of the international field experiment RECONCILE are presented. First of all, and as a kind of reference, the evolution of the polar vortex in its different phases is documented. Special emphasis is put on explaining the formation of the exceptionally cold vortex in mid winter after a sequence of stratospheric disturbances which were caused by upward propagating planetary waves. A major sudden stratospheric warming (SSW) occurring near the end of January 2010 concluded the anomalous cold vortex period. Wave ice polar stratospheric clouds were frequently observed by spaceborne remote-sensing instruments over the Arctic during the cold period in January 2010. Here, one such case observed over Greenland is analysed in more detail and an attempt is made to correlate flow information of an operational numerical weather prediction model to the magnitude of the mountain-wave induced temperature fluctuations. Finally, it is shown that the forecasts of the ECMWF ensemble prediction system for the onset of the major SSW were very skilful and the ensemble spread was very small. However, the ensemble spread increased dramatically after the major SSW, displaying the strong non-linearity and internal variability involved in the SSW event.
Mixing state and compositional effects on CCN activity and droplet growth kinetics of size-resolved CCN in an urban environment
Authors: Padró L. T. , Moore R. H. , Zhang X. , Rastogi N. , Weber R. J. , Nenes A.
Published: December 2011

Abstract. Aerosol composition and mixing state near anthropogenic sources can be highly variable and can challenge predictions of cloud condensation nuclei (CCN). We present in-situ size-resolved CCN measurements to quantify this predictive uncertainty, which were carried out during the 2008 summertime August Mini Intensive Gas and Aerosol Study (AMIGAS) campaign in Atlanta, GA. Aerosol chemical composition was measured by two particle-into-liquid samplers measuring water-soluble inorganic ions and total water-soluble organic carbon. Size-resolved CCN data were collected using the Scanning Mobility CCN Analysis (SMCA) method and were used to obtain characteristic aerosol hygroscopicity distributions, whose breadth reflects the aerosol compositional variability and mixing state. We find that knowledge of aerosol mixing state is important for accurate predictions of CCN concentrations and that the influence of an externally-mixed, non-CCN-active aerosol fraction varies with size from 31% for particle diameters less than 40 nm to 93% for accumulation mode aerosol during the day. This is likely indicative of the interactions between biogenic and anthropogenic emissions which contribute to the formation and transformation of aerosols in this heterogeneous environment. Assuming size-dependent aerosol mixing state and size-invariant chemical composition decreased the average CCN concentration overprediction from greater than 50–200% to less than 20%. CCN activity was parameterized using a single hygroscopicity parameter, κ, which averaged 0.16 ± 0.07 for 80 nm particles and exhibited considerable variability (range: 0.03–0.48) throughout the study period.
Ability of the MAX-DOAS method to derive profile information for NO2: can the boundary layer and free troposphere be separated?
Authors: Vlemmix T. , Piters A. J. M. , Berkhout A. J. C. , Gast L. F. L. , Wang P. , Levelt P. F.
Published: December 2011

Abstract. Multiple Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) instruments can measure from the ground the absorption by nitrogen dioxide (NO2) of scattered sunlight seen in multiple viewing directions. This paper studies the potential of this technique to derive the vertical distribution of NO2 in the troposphere. Such profile information is essential for detailed comparisons of MAX-DOAS retrievals with other measurement techniques for NO2, e.g. with a lidar or from space. The retrieval algorithm used is based on a pre-calculated look-up table and assumes homogeneous mixing of aerosols and NO2 in layers extending from the surface to a variable height. Two retrieval models are compared: one including and one excluding an elevated NO2 layer at a fixed altitude in the free troposphere. An ensemble technique is applied to derive retrieval uncertainties. Sensitivity studies demonstrate that NO2 in the free troposphere can only be retrieved accurately if: (i) the retrieved boundary layer profiles for aerosols and NO2 correspond to the real ones, (ii) if the right a-priori choice is made for the (average) height of free tropospheric NO2, and (iii) if all other error sources are very low. It is shown that retrieval models that are capable of accurate NO2 retrievals in the free troposphere, i.e. models not constrained too much by a-priori assumptions, have as a major disadvantage that they will frequently find free tropospheric NO2, also when it is not present in reality. This is a consequence of the fact that NO2 in the free troposphere is poorly constrained by the MAX-DOAS observations, especially for high aerosol optical thickness values in the boundary layer. Retrieval of free tropospheric NO2 is therefore sensitive to a large number of error sources. For this reason it is advised to firmly constrain free tropospheric NO2 in MAX-DOAS retrieval models used for applications such as satellite validation. This effectively makes free tropospheric NO2 a source of error for MAX-DOAS retrieval of NO2 profiles in the boundary layer. A comparison was performed with independent data, based on MAX-DOAS observations done at the CINDI campaign, held in the Netherlands in 2009. Comparison with lidar partial tropospheric NO2 columns showed a correlation of 0.78, and an average difference of 0.1× 1015 molec cm−2. The diurnal evolution of the NO2 volume mixing ratio measured by in-situ monitors at the surface and averaged over five days with cloud-free mornings, compares well to the MAX-DOAS retrieval: a correlation was found of 0.94, and an average difference of 0.04 ppb.
Effects of stoichiometry and temperature perturbations on beech litter decomposition, enzyme activities and protein expression
Authors: Keiblinger K. M. , Schneider T. , Roschitzki B. , Schmid E. , Eberl L. , Hämmerle I. , Leitner S. , Richter A. , Wanek W. , Riedel K. , Zechmeister-Boltenstern S.
Published: December 2011

Abstract. Microbes are major players in leaf litter decomposition and therefore advances in the understanding of their control on element cycling are of paramount importance. Our aim was to investigate the influence of leaf litter stoichiometry in terms of carbon (C) : nitrogen (N) : phosphorus (P) on the decomposition process, and to follow changes in microbial community structure and function in response to temperature-stress treatments. To elucidate how the stoichiometry of beech litter (Fagus sylvatica L.) and stress treatments interactively affect the decomposition processes, a terrestrial microcosm experiment was conducted. Beech litter from different Austrian sites covering C:N ratios from 39 to 61 and C:P ratios from 666 to 1729 were incubated at 15 °C and 60% moisture for six months. Part of the microcosms were then subjected to severe changes in temperature (+30 °C and −15 °C) to monitor the influence of temperature stress. Extracellular enzyme activities were assayed and respiratory activities measured. A semi-quantitative metaproteomics approach (1D-SDS PAGE combined with liquid chromatography and tandem mass-spectrometry; unique spectral counting) was employed to investigate the impact of the applied stress treatments in dependency of litter stoichiometry on structure and function of the decomposing community. In litter with narrow C:nutrient ratios microbial decomposers were most abundant. Cellulase, chitinase, phosphatase and protease activity decreased after heat and frost treatments. Decomposer communities and specific functions varied with site i.e. stoichiometry. The applied stress evoked strong changes of enzyme activities, dissolved organic nitrogen and litter pH. Freeze treatments resulted in a decline in residual plant litter material, and increased fungal abundance indicating slightly accelerated decomposition. Overall, we could detect a strong effect of litter stoichiometry on microbial community structure as well as function. Temperature perturbations resulted in short- to medium-term alterations of microbial function, especially heat blocked decomposing enzymes.
High resolution tsunami inversion for 2010 Chile earthquake
Authors: Wu T.-R. , Ho T.-C.
Published: December 2011

Abstract. We investigate the feasibility of inverting high-resolution vertical seafloor displacement from tsunami waveforms. An inversion method named "SUTIM" (small unit tsunami inversion method) is developed to meet this goal. In addition to utilizing the conventional least-square inversion, this paper also enhances the inversion resolution by Grid-Shifting method. A smooth constraint is adopted to gain stability. After a series of validation and performance tests, SUTIM is used to study the 2010 Chile earthquake. Based upon data quality and azimuthal distribution, we select tsunami waveforms from 6 GLOSS stations and 1 DART buoy record. In total, 157 sub-faults are utilized for the high-resolution inversion. The resolution reaches 10 sub-faults per wavelength. The result is compared with the distribution of the aftershocks and waveforms at each gauge location with very good agreement. The inversion result shows that the source profile features a non-uniform distribution of the seafloor displacement. The highly elevated vertical seafloor is mainly concentrated in two areas: one is located in the northern part of the epicentre, between 34° S and 36° S; the other is in the southern part, between 37° S and 38° S.
Passport for a Hoped Immortality
Authors: Memmi Albert
Published: December 2011

Acceptance speech delivered to the Bernheim Foundation of French Judaism on May 16, 2011. Translated with the author's permission by Scott Davidson.
Preface to The Pillar of Salt
Authors: Camus Albert
Published: December 2011

The first English translation of Albert Camus' "Preface" to Albert Memmi's first book, La Statue de Sel (The Pillar of Salt). Translated with permission by Scott Davidson.
Perceptual Comparisons With Laterally Presented Pictures and Environmental Sounds
Authors: Goolkasian Paula , Finkelstein Samantha , Stubblefield Alexandra
Published: December 2011

Two experiments studied perceptual comparisons with cues that vary in one of four ways (picture, sound, spoken word, or printed word) and with targets that are either pictures or environmental sounds. The basic question probed whether modality or differences in format were factors that would influence picture and sound perception. Also of interest were cue effect differences when targets are presented on either the right or left side. Students responded to a same-different reaction time task that entailed matching cue-target pairs to determine whether the successive stimulus events represented features drawn from the same basic item. Cue type influenced reaction times to pictures and environmental sounds, but the effects were qualified by response type and with picture targets by presentation side. These results provide some additional evidence of processing asymmetry when pictures are directed to either the right or left hemisphere, as well as for some asymmetries in cross-modality cuing. Implications of these findings for theories of multisensory processing and models of object recognition are discussed.
Interaction Trap/Two‐Hybrid System to Identify Interacting Proteins
Authors: Golemis Erica A. , Serebriiskii Ilya , Finley Russell L. , Kolonin Mikhail G. , Gyuris Jeno , Brent Roger
Published: December 2011

The yeast two‐hybrid method (or interaction trap) is a powerful technique for detecting protein interactions. The procedure is performed using transcriptional activation of a dual reporter system in yeast to identify interactions between a protein of interest (the bait protein) and the candidate proteins for interaction. The method can be used to screen a protein library for interactions with a bait protein or to test for association between proteins that are expected to interact based on prior evidence. Interaction mating facilitates the screening of a library with multiple bait proteins.Curr. Protoc. Cell Biol. 53:17.3.1‐17.3.35. © 2011 by John Wiley & Sons, Inc.
Methods for Growing and Titrating African Swine Fever Virus: Field and Laboratory Samples
Authors: Carrascosa Angel L. , Bustos M. Jose , de Leon Patricia
Published: December 2011

Growing African swine fever virus (ASFV) isolates obtained mainly from the field, but also engineered in the laboratory, is a critical step for diagnosis, titration, or virus infection studies. This unit describes a set of methods and protocols to produce and titrate any ASFV strain in cell cultures. The procedures include (1) basic techniques to prepare virus‐sensitive target cells; (2) strategies for growth, concentration, and purification of virus stocks; and (3) the semi‐quantitative (end dilution) and quantitative (plaque) assays for the determination of viral titers, and the use of different ASFV‐sensitive cells as targets for virus production and titration. Curr. Protoc. Cell Biol. 53:26.14.1‐26.14.25. © 2011 by John Wiley & Sons, Inc.
Aluminum: Inorganic Chemistry
Authors: Apblett Allen W.
Published: December 2011

Aluminum is the most abundant metal to be found in the earth's crust (8.1%). It is component of gemstones and many common minerals such as granite and clays. Aluminum is a very reactive metal and is not found in an uncombined form in nature. However, the use of its compounds has a very long history. For example, the ancient Greeks and Romans used alum as an astringent and as a mordant in dyeing. The pure metal was isolated first by Wohler in 1827. The modern method for obtaining aluminum metal is the electrolysis of alumina dissolved in cryolite. Aluminum can also be produced from clay, but the process is not economically feasible at present.

Pure aluminum, a silvery‐white metal, possesses many desirable characteristics. It is light, nonmagnetic, and nonsparking, and is second amongst all metals in the scale of malleability, and sixth in ductility. It is extensively used for kitchen utensils, outside building materials, airplanes, and in thousands of industrial applications where a strong, light, easily constructed material is needed. Pure aluminum is soft and lacks strength, but when it is alloyed with small amounts of copper, silicon, magnesium, manganese, or other elements these shortcomings can be circumvented. The aluminum compounds of greatest importance are aluminum oxide, aluminum sulfate, aluminum potassium sulfate (alum), and aluminum halides. The oxide, alumina, occurs naturally as ruby (Al2O3), sapphire, corundum, and emery, and is used in glassmaking and refractory ceramic materials. Synthetic ruby and sapphire are used in lasers for producing coherent light. Aluminum nitride, phosphide, and antimonide are important materials for the semiconductor industry. Aluminum halides and oxides are also very important catalyst supports.
Analytical Chemistry of the Transition ElementsBased in part on the article Analytical Chemistry of the Transition Elements by Harry M. N. H. Irving & Alan T. Hutton which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Hutton Alan T.
Published: December 2011

This article is concerned with the determination of what transition elements are present in a sample and their concentration. After considering the general nature of the problems confronting the analyst, a historical overview is given describing the development of the analytical chemistry of the transition elements from biblical times through to the nascent technologies of the eighteenth and nineteenth centuries. After a brief consideration of the treatment required by materials to get them in a form suitable for analysis, for example, sampling and digestion, the classical methods of gravimetry and titrimetry are discussed, with special emphasis on the use of organic reagents and on complexometric determinations using ethylenediaminetetraacetic acid (EDTA). The role of organic reagents is also seen to be important in spectrophotometric analysis or absorptiometry. Consideration is next given to the various modern instrumental techniques available for analysis of the transition elements, starting with various forms of atomic emission spectroscopy but giving emphasis to the inductively coupled plasma (ICP) sources. The widely used technique of atomic absorption spectroscopy (AAS) is next described, along with its many applications for the determination of transition elements in many diverse materials, from body fluids to engine oils. The modern day importance of X‐ray fluorescence (XRF) is highlighted in a discussion of X‐ray methods, while the technique of neutron activation analysis dominates the section on activation methods, this approach being of particular importance where a nondestructive analysis is essential, for example, of a museum artifact. Finally, brief consideration is given to the importance of the platinum group metals (PGMs) and the special analytical problems that they present.
Antimony: Organometallic ChemistryBased in part on the article Antimony: Organometallic Chemistry by Alan Berry which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Breunig Hans Joachim
Published: December 2011

This article presents a concise overview on the chemistry of organoantimony compounds containing one or more Sb–C bonds. It deals with homoleptic molecules where Sb is bonded exclusively to organic groups R, for example tri‐ or pentorganyls of antimony, and with heteroleptic derivatives where RnSb groups (n = 1, 2, 4) are bonded to other elements. Not only compounds with single bonds between Sb and C but also molecules with double bond character are considered.
Arsenic: Organoarsenic Chemistry
Authors: Krannich Larry K. , Watkins Charles L.
Published: December 2011

This review surveys the chemistry, reactivity, spectroscopic, and structural aspects of several major classes of organometallic arsenic compounds over the time period of 1760 through 2003. These compounds are the core of the field and represent the major areas of research thrusts during this period. We draw heavily from several books, monographs, and review articles to review the primary synthetic routes and reactivity. The primary literature is referenced for all developments that have occurred since the last published review articles. After an extensive review of the fully substituted and AsH bond containing organoarsenic compounds, the focus is on compounds containing AsHalogen, As group 13, As group 14, As group 15, and AsO bonds. Because of the efforts to synthesize As group 13 bonded compounds of the heavier group 13 elements, tables listing the known compounds synthesized after 1985 and their method of preparation are provided.
Bismuth: Inorganic Chemistry
Authors: Whitmire Kenton H.
Published: December 2011

Solid state and molecular compounds of bismuth have many interesting and useful properties. In addition to bismuth alloys, this article describes simple binary compounds such as the bismuthine, bismuth halides, carboxylates, alkoxides, thiolates, dithiocarbamates and oxides are described in addition to coordination compounds based upon them. Some of these compounds have antibacterial and/or antifungal properties. They have also been used to treat gastrointestinal diseases. Also described are reduced bismuth cluster compounds and transition metal cluster compounds incorporating.
Bismuth: Organometallic Chemistry
Authors: Whitmire Kenton H.
Published: December 2011

Bismuth readily forms a variety of tri‐ and pentavalent organic derivatives by the reactions of bismuth halides with Grignard, organolithium, organozinc, or organoaluminum reagents. Bismuth(III) triaryl compounds are readily oxidized by chlorine and bromine to triaryl dihalides, while iodine reacts to produce aryl bismuth iodides. Some organobismuth compounds are Lewis acidic, showing the ready formation of higher coordination number adducts with traditional ligands. A variety of organobismuth compounds with bismuth–bismuth and bismuth–transition metal bonds are described. Organobismuth(V) have found uses as selective oxidants and aryl transfer reagents.
Bonding Energetics of Organometallic Compounds
Authors: Dorta Reto , Nolan Steven P.
Published: December 2011

This contribution gives an overview of solution calorimetric studies carried out on organometallic complexes in the last decade. A special focus has been put on a close investigation of metal–ligand exchange reactions involving different ligand and metal systems. Ligand substitution reactions are at the heart of many catalytic transformations, since creation of vacant coordination sites often require liberation of one or more ligands from the coordination sphere of the metal. Detailed analyses of phosphine‐, phosphite‐, and NHC‐ (NHC = N‐heterocyclic carbene) ruthenium, rhodium, and platinum systems show that enthalpies of ligand substitution reactions are associated to electronic and/or steric variation of the ligands. They can be explained in terms of different amounts of these two contributions to the overall enthalpy. Extensive calorimetric studies on ligand substitutions showed that cis disposition of the ligands leads to an overwhelmingly steric contribution to the enthalpy of ligand substitution, whereas trans disposition of the ligands gives enthalpy values that are highly dependent on the electronic nature of the ligand systems studied. Thermodynamic studies of addition reactions of organic molecules to metal fragments are equally crucial in catalysis and gave valuable thermodynamic data for CO, H2, aldehyde, acyl chloride addition reactions to catalytically relevant rhodium systems. Thermodynamic data for different reductive cleavage reactions of organic fragments involving molybdenum systems are also presented.
Boron–Nitrogen CompoundsBased in part on the article Boron–Nitrogen Compounds by Robert T. Paine which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Bakus Ronald C. , Atwood David A.
Published: December 2011

The majority of this article details the many synthetic routes and compounds that can be accessed in combinations of boron reagents with amines. Lewis acid‐base adducts are the simplest type of compounds, and lead into the more complex aminoboranes and iminoboranes. Owing to their widespread importance and usage, the borazines, pyrazaboles, and polypyrazaolyborates are covered in separate sections. The newly emerging fields of boron–nitrogen cations and boron nitride solid‐state materials are covered in detail.
Cadmium: Inorganic & Coordination Chemistry
Authors: Borsari Marco
Published: December 2011

This article provides an overview on the chemistry of cadmium. Cadmium is a naturally occurring metal elements, being the 67th most abundant element in the earth's crust, and it is found in several minerals. Occurrence, production and applications have been surveyed, also in the light of toxicological and environmental risks joined to uses of cadmium. The usual oxidation state of cadmium is 2+ and its chemistry closely resembles that of zinc. The versatile coordination ability allows a wide variety of structure. Therefore, emphasis is placed on stereochemical aspects of cadmium chemistry, in particular on 1D, 2D, and 3D architectures resulting from assembly of Cd
2+
–ligand(s) units. The main compounds and complexes, ordered by metal oxidation state and ligand donor atom, have been examined in their properties and structural aspects, both in solution and in solid state.
Calcium‐Binding ProteinsBased in part on the article Calcium‐Binding Proteins by Natalie C. J. Strynadka & Michael N. G. James which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Yang Jenny J. , Yang Wei
Published: December 2011

Ca2+is an important second messenger in the regulation of cell life cycle in addition to being an essential component in biomineralization. Ca2+mediates its action in regulation by binding to Ca2+receptors/proteins that in turn regulate signal transduction, enzymatic activity, and protein stability. During the past few years, owing to the fast progress in genomic information and structural biological studies, our understanding of calcium‐binding proteins has been greatly expanded. Since 1991, the structures of calcium‐binding proteins have been extended to more than 1000 today and calcium‐binding proteins are found in every cellular compartment. In this article, we will first summarize the current knowledge about the common properties of calcium‐binding proteins. We then will highlight recent developments in structural biology and biological functions of calcium‐binding proteins.
Carbides: Transition Metal Solid‐State ChemistryBased in part on the article Carbides: Transition Metal Solid State Chemistry by Peter Ettmayer & Walter Lengauer which appeared in the
Encyclopedia of Inorganic Chemistry, First Edition
.
Authors: Lengauer Walter , Eder Alexander
Published: December 2011

Basic properties and use of transition metal carbides and carbonitrides are presented in this article. Starting from crystal chemistry, bonding, and preparation, the article also briefly discusses analytical chemistry of chemical and physical carbon analysis as well as thermodynamics. Updated versions of phase diagrams of group 4, 5, and 6 transition metals with carbon as well as phase diagrams of FeC and MnC are presented together with those of the most important transition metal carbonitride systems TiCN and ZrCN. A large part is devoted to the solid‐state properties because they make carbides and carbonitrides interesting materials for application. The presentation of these properties includes hardness, thermal properties, conductivities, carbon diffusivity, and elastic properties. Some ternary and quaternary carbonitrides are also discussed. Several of these properties are given as a function of temperature and composition. Examples for application of carbides in modern hardmetal types such as recent development in fine‐grained hardmetals and functional gradient hardmetals are included. The topic is closely connected to the article Nitrides: Transition Metal Solid State Chemistry.
Cation‐Activated Enzymes
Authors: Glusker Jenny P.
Published: December 2011

Cation‐activated enzymes are those that require a cation for maximal activity but which still have some activity in the absence of the cation, that is, the activating cation is not an essential part of the enzyme mechanism. The cations involved are generally metal or ammonium ions. The metal ions used are generally Na+, K+, Mg2+, or Ca2+, those that are abundant in nature. In the last 10 years, many crystal structures of cation‐activated enzymes have been determined and, in these studies, potassium is the most common activating cation. The geometry of binding and possible conclusions about this activity are the subject of this review. Chosen for description are thrombin (a sodium‐activated enzyme), pyruvate kinase, dialkylglycine decarboxylase, diol dehydrase, inosine monophosphate dehydrogenase, and tryptophanase (all potassium‐activated enzymes), and alkaline phosphatase (a magnesium‐activated enzyme). In some enzymes, the activating cation is near the active site, but in others it is distant. This implies that its function in these two possibilities involves the modification of the charge distribution in the reaction center or else stabilization of the enzyme conformation most suited to the reaction to be catalyzed. These studies provide information on one way in which nature controls enzyme activity, and hopefully further studies will help us learn more possibilities for utilizing these enzyme‐control strategies in medicine.
Chlorine, Bromine, Iodine, & Astatine: Inorganic ChemistryBased in part on the article Chlorine, Bromine, Iodine, & Astatine: Inorganic Chemistry by Jacob Shamir which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Lang Jian‐Ping
Published: December 2011

This chapter summarizes the occurrences, atomic structures, and molecular properties of the elements of group 17, chlorine, bromine, iodine, and astatine. The charge‐transfer complexes of halogens with different inorganic or organic compounds are outlined. The interhalogen compounds, especially those of polyiodides, are discussed with respect to their preparation and their structure varieties. The halogen oxides such as halogen oxide cations, halogen oxide fluorides, oxoacids and oxoacid salts, and halogen derivatives of oxoacids are discussed. Finally, organic polyvalent halogen derivatives, mainly including those of iodine (I), iodine (III), and iodine (V), are mentioned.
Chromium: Organometallic Chemistry
Authors: Theopold Klaus H. , Kucharczyk Robin R.
Published: December 2011

Starting with Hein's investigation of the reaction of CrCl3with PhMgBr in the beginning of the twentieth century, chromium organometallic chemistry is now marked by an ever increasing diversity of compound types and formal oxidation states. Organochromium compounds such as Cr(CO)6, (η6‐C6C6)2Cr, and (OC)5CrC(OMe)Ph represent milestones in the development of organometallic chemistry as a whole. The lower oxidation states (−IV to +II) are dominated by chromium carbonyl complexes with 18 electron configurations, while midvalent compounds (+II, +III) often feature cyclopentadienyl rings and exhibit unpaired electrons. Organometallic compounds of chromium in its highest oxidation states (+IV to +VI) are still relatively rare, but this has been a growing area of late. Much of the interest in chromium alkyls is due to the metal's important role in the catalysis of olefin polymerization. Homogeneous model systems for the Union Carbide catalyst (Cp2Cr/SiO2) and the Phillips catalyst (CrO3/SiO2) still motivate much synthetic work. Applications of organochromium chemistry in organic synthesis are also becoming more numerous and useful.
Coordination Chemistry: History
Authors: Kauffman George B.
Published: December 2011

This article discusses a chronological history of the major discoveries, both theoretical and experimental, of coordination chemistry from antiquity through 2003. In view of Alfred Werner's central role in the field, considerable space is allotted to his achievements, but contributions of lesser‐known pioneers are also included. Some of the most historically significant coordination compounds are first discussed, along with several pre‐Werner theories of their formation, constitution, and configuration, followed by Werner's theory and his most important discoveries.
Copper: Hemocyanin/Tyrosinase ModelsBased in part on the article Copper: Hemocyanin/Tyrosinase Models by Nobumasa Kitajima which appeared in the
Encyclopedia of Inorganic Chemistry, First Edition
.
Authors: Shearer Jason , Karlin Kenneth D.
Published: December 2011

Coupled dinuclear copper(II) centers are found in metalloenzymes such as hemocyanin (Hc), tyrosinase (Tyr), and catechol oxidase (Co), and perform functions such as dioxygen transport,
o
‐phenol aromatic hydroxylations, and dehydrogenation of
o
‐catechols. These enzymes all contain two‐copper centers, each ligated by imidazole nitrogen ligands from histidine residues, and in their oxyforms are bridged by a μ‐η
2
:η
2
‐peroxo moiety. Synthetic model compounds have proven useful in elucidating a number of different aspects of the protein chemistry, such as spectroscopic and structural properties. Also, new coordination chemistry has been developed, such as a new and possibly important equilibrium form of the μ‐η
2
:η
2
‐peroxo‐

$\hbox{Cu}^{{\rm II}}_{2}$

species, namely, the

$\hbox{Cu}^{{\rm III}}_{2}$

‐bis‐μ‐oxo moiety. In conjunction with stopped‐flow kinetic studies, new fundamental reactions involving Cu
I
complexes and dioxygen have also been elucidated, such as the demonstration that an initial Cu
II
‐superoxo species is formed prior to

$\hbox{Cu}^{{\rm II}}_{2}$

‐peroxo formation. Both species are enthalpically favored at low temperatures, but an unfavorable entropy term precludes the isolation of many of these complexes near room temperature. Considerable efforts are directed towards elucidation of detailed mechanistic pictures for substrate oxidations with copper–dioxygen adducts.
Ortho
‐phenol hydroxylations proceed
via
an electrophilic aromatic substitution reaction. The mechanism of Co activity is still widely debated with evidence in model systems pointing towards both proton‐coupled electron transfer pathways, as well as direct hydrogen atom transfer reaction. Such mechanistic inquiries, and determining the differential reactivity of μ‐η
2
:η
2
‐peroxo‐

$\hbox{Cu}^{{\rm II}}_{2}$

and

$\hbox{Cu}^{{\rm III}}_{2}$

‐bis‐μ‐oxo complexes, are of continuing and future interest.
Copper: Inorganic & Coordination ChemistryBased in part on the article Copper: Inorganic & Coordination Chemistry by Rebecca R. Conry & Kenneth D. Karlin which appeared in the
Encyclopedia of Inorganic Chemistry, First Edition
.
Authors: Conry Rebecca R.
Published: December 2011

Copper was one of the first metals used widely because the metal is fairly plentiful (among the 25 most abundant elements in the earth's crust) and can be found in its metallic state. In addition, the metal and its alloys have a number of beneficial qualities including ductility, malleability, strength, corrosion resistance, and high thermal and electrical conductivity, combined with an attractive appearance. Copper is also an essential trace nutrient for organisms ranging from bacteria to mammals.

Copper exhibits a rich coordination chemistry with complexes known in oxidation states ranging from 0 to +4, although the +2 (cupric) and the +1 (cuprous) oxidation states are by far the most common, with +2 predominating. Compounds of copper have found extensive practical usage, including as catalysts in both homogeneous and heterogeneous reactions, as fungicides, pesticides, and wood preservatives, as pigments for paints and glasses, and in the so‐called high‐temperature superconductors.

The coordination numbers and geometries of copper complexes vary with oxidation state. For the spherically symmetric d
10
Cu
I
ion, the common geometries are two‐coordinate linear, three‐coordinate trigonal planar, and four‐coordinate tetrahedral. Cu
I
compounds are diamagnetic and colorless, except where color results from charge‐transfer bands or a counterion; these complexes are often fairly readily oxidized to Cu
II
compounds. The d
9
Cu
II
ion is usually found in a tetragonal coordination environment, with four short equatorial bonds and another one or two longer axial bonds although complexes with other structures are known, including tetrahedral, square planar, and trigonal bipyramidal geometries. Most of the Cu
II
compounds are blue or green because of d–d absorptions in the 600 to 900‐nm region; exceptions generally also have charge‐transfer bands tailing into the visible, causing a red or brown appearance. Cu
III
complexes are typically square planar and diamagnetic.
Copper: Organometallic ChemistryBased in part on the article Copper: Organometallic Chemistry by Bruce H. Lipshutz & Michael R. Wood which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Lipshutz Bruce H. , Pfeiffer Steven S.
Published: December 2011

Much of copper chemistry over the past decade has transitioned toward catalysis, driven in large measure by environmental rather than economic concerns. Catalytic processes have appeared in large numbers, in particular due to the advances made in both the design of new ligands that effectively coordinate copper, but also due to their increased availability. Applications of copper‐catalyzed processes to bond formations have gone well‐beyond those of a CC nature, nowadays including CN, CO, CS, CP, and CH types. Asymmetric variants based on nonracemically ligated copper salts and copper hydride have led to highly valued entries to chiral products of great use in synthesis. Transmetalations from various metals (e.g. Zn, Zr, etc.) to copper also continue to play a vital role in organic synthesis, and are discussed herein as well.

Considerable progress on many physical organic fronts relating to copper chemistry has been made. New advances in technologies that shed light on structural aspects of copper reagents are now available (extended X‐ray absorption fine structure, EXAFS, X‐ray absorption near edge structure, XANES) and are being used to accompany X‐ray analyses and highly sophisticated NMR techniques. High‐level computer calculations have led to theoretical ‘pictures’ illustrating the mechanistic pathways that may be followed by some of the most commonly used reactions in copper chemistry (e.g. 1,4‐additions). Taken in their entirety, these developments suggest that this past decade has been a most productive period in the continuing evolution of copper chemistry.
Copper Proteins: Oxidases
Authors: Stoj Christopher S. , Kosman Daniel J.
Published: December 2011

Oxidases are enzymes that use dioxygen as the electron acceptor in oxido‐reduction reactions. Many members of this enzyme class (EC 1.) rely on the Cu1+/Cu2+redox cycle of copper prosthetic group(s) in their catalysis of the electron transfer from reducing substrate to O2. Those copper oxidases that catalyze the four‐electron reduction of O2to 2H2O are known as multicopper oxidases (MCO) because each member of this group contains at least four copper atoms of three distinct electronic and spectral types. These three types are: type 1 or ‘blue’ Cu(II), so‐called because of its distinguishing strong absorbance at ∼600 nm; type 2 Cu(II), comparable in electronic structure to that found in square‐planar copper complexes; and type 3 Cu(II), a Cu(II)Cu(II) pair bridged by O(H) and thus diamagnetic. With four 1e−metal redox sites, MCOs are the all‐copper equivalent of the copper‐heme respiratory terminal oxidases. However, MCOs are true oxidases in that all members can use as electron acceptors common (di)phenolic, and aromatic (di)amine substrates, for example, hydroquinone, ascorbic acid, and phenylenediamine. The laccases and ascorbate oxidase are examples of these MCOs (EC 1.10.3). Members of a separate MCO class (EC 1.16.3) also use lower valent metal ions as substrates, for example, Fe2+, Cu1+, and/or Mn2+. These are thereby designated metallo‐oxidases; the most widely studied activity of this class has been towards Fe2+giving rise to the common enzyme name, ferroxidase. The typical MCO structure consists of three ‘cuprodoxin’ domains, a Greek‐key beta‐fold that characterizes a family of mononuclear copper electron‐transfer factors. Among MCOs are both soluble and type 1 membrane proteins. Functionally, MCOs are known to play essential roles in biodegradation and transformation, cell redox balance, and metal metabolism. This article summarizes current knowledge of this class of copper oxidase enzymes.
Cyanide Complexes of the Transition MetalsBased in part on the article Cyanide Complexes of the Transition Metals by Timothy P. Hanusa & David J. Burkey which appeared in the
Encyclopedia of Inorganic Chemistry, First Edition
.
Authors: Hanusa Timothy P.
Published: December 2011

Cyano metal complexes contain one or more bound cyanide ligands, CN
−
, and constitute one of the largest and longest‐known classes of compounds in inorganic chemistry. Like carbon monoxide, the cyanide ion can function as a π‐acid ligand, but because of its negative charge, the cyanide ion can also form strong sigma bonds. This bifunctional behavior allows CN
−
to stabilize both high and low oxidation states of metals. The cyanide ion can bind to metals in both terminal and bridging (MCNM′) modes; the bridges are commonly linear, and are present in Prussian blue and many other polymeric metal cyanides. Framework solids with high degrees of void space can be formed with bridging cyanide ligands. Cyano metal complexes undergo a variety of oxidation‐reduction reactions, but owing to the strong σ‐donor properties of CN
−
, only a few ligands are capable of directly replacing metal‐bound cyanide. For most substitution reactions, photochemically induced dissociation of one or more of the CN
−
ligands is needed. Cyano complexes are used as pigments and dyes, and are being increasingly explored as electroactive, zeolitic, and chemical sensing materials.