bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of optical and microphysical properties of thin warm clouds using ground based hyper-spectral analysis
Authors: Hirsch E. , Agassi E. , Koren I.
Published: December 2011

Abstract. Clouds play a critical role in the Earth's radiative budget as they modulate the atmosphere by reflecting shortwave solar radiation and absorbing long wave IR radiation emitted by the Earth's surface. Although extensively studied for decades, cloud modelling in global circulation models is far from adequate, mostly due to insufficient spatial resolution of the circulation models. In addition, measurements of cloud properties still need improvement, since the vast majority of remote sensing techniques are focused in relatively large, thick clouds. In this study, we utilize ground based hyperspectral measurements and analysis to explore very thin water clouds. These clouds are characterized by liquid water path (LWP) that spans from as high as ~50 g m−2 and down to 65 mg m−2 with a minimum of about 0.01 visible optical depth. The retrieval methodology relies on three elements: a detailed radiative transfer calculations in the longwave IR regime, signal enhancement by subtraction of a clear sky reference, and spectral matching method which exploits fine spectral differences between water droplets of different radii. A detailed description of the theoretical basis for the retrieval technique is provided along with a comprehensive discussion regarding its limitations. The proposed methodology was validated in a controlled experiment where artificial clouds were sprayed and their effective radii were both measured and retrieved simultaneously. This methodology can be used in several ways: (1) the frequency and optical properties of very thin water clouds can be studied more precisely in order to evaluate their total radiative forcing on the Earth's radiation budget. (2) The unique optical properties of the inter-region between clouds (clouds' "twilight zone") can be studied in order to more rigorously understanding of the governing physical processes which dominate this region. (3) Since the optical thickness of a developed cloud gradually decreases towards its edges, the proposed methodology can be used to study the spatial microphysical behaviour of these edges. (4) A spatial-temporal analysis can be used to study mixing processes in clouds' entrainment zone.
Correction technique for raman water vapor lidar signal dependent bias and suitability for water vapor trend monitoring in the upper troposphere
Authors: Whiteman D. N. , Cadirola M. , Venable D. , Calhoun M. , Miloshevich L. , Vermeesch K. , Twigg L. , Dirisu A. , Hurst D. , Hall E. , Jordan A. , Vömel H.
Published: December 2011

Abstract. The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE mobile laboratory in the MOHAVE-2009 campaign. In an appendix we also report on the performance of the corrected Vaisala RS92 radiosonde during the campaign. A new radiosonde based calibration algorithm is presented that reduces the influence of atmospheric variability on the derived calibration constant. The MOHAVE-2009 campaign permitted all Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated revealing that wet biases in upper tropospheric and lower stratospheric water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the data. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most resistant to additional noise sources. The correction shown here holds promise for permitting useful upper tropospheric water vapor profiles to be consistently measured by Raman lidar within NDACC and elsewhere despite the prevalence of instrumental and atmospheric effects that can contaminate the very low signal to noise measurements in the UT.
Lecanora wrightiana and Rhizocarpon inimicum, rare lichens new to Turkey and the Middle East
Authors: Yazıcı Kenan , Aptroot André , Aslan Ali
Published: December 2011

During a recent excursion in Igdır region (Turkey), we sampled lichens from two localities, among which Lecanora wrightiana and Rhizocarpon inimicum were determined as new to Turkey and the Middle East. Geographic distribution, substrate, chemistry, and comparisons
with morphologically similar taxa are presented.
A new volvate Macrolepiota (Agaricomycetes, Agaricales) from Italy, with observations on the M. procera complex
Authors: Vizzini Alfredo , Contu Marco , Ghignone Stefano , Vellinga Else
Published: December 2011

A new Macrolepiota taxon from Italy, M. rhodosperma var. velicopia, is described and illustrated based on morphological and ITS rDNA data. It is characterized by a well-developed volva and abundant, evident velar remnants on the pileus, a stipe with a minutely
squamulose covering, and very thick-walled elements in the pileipellis. A discussion on its taxonomic position within Macrolepiota and notes on closely related taxa are provided. DNA sequence analyses support the new taxon within the variability of M. fuliginosa sensu
Vellinga, a non-volvate taxon that differs from Barla's original sense of M. fuliginosa. As Barla did not indicate a holotype in his protologue of Lepiota procera var. fuliginosa and there are no extant original herbarium specimens, Barla's Fig. 5/PL. 9 (from Les
champignons des Alpes maritimes) is selected as a lectotype, and a recent collection from Liguria (Italy) is chosen as the epitype. A recent collection from Sardinia is chosen as epitype for L . permixta. Finally, M. fuliginosa and M. permixta are
reduced in rank to forms of M. procera, based on their morphology.
Studies on Cephalotrichum from soils in China — twelve new species and two new combinations
Authors: Jiang Yu-Lan , Xu Jun-Jie , Wu Yue-Ming , Zhang Yue-Li , Liu Hui-Mei , Pan Hao-Qin , Zhang Tian-Yu
Published: December 2011

A study of Cephalotrichum species diversity in soils of China resulted in twelve new species: Cephalotrichum acutisporum, C. cylindrosporum, C. ellipsoideum, C. inflatum, C. longicollum, C. macrosporum, C. oblongum, C. ovoideum,
C. robustum, C. spirale, C. terricola, C. verrucipes. These species are illustrated and described in this paper. The type specimens (dried cultures) and living cultures are deposited in the Plant Pathology Herbarium of Shandong Agricultural University (HSAUP). Two
Doratomyces species are transferred to Cephalotrichum.
Additional records of Volvariella dunensis (Basidiomycota, Agaricales): morphological and molecular characterization
Authors: Vizzini Alfredo , Contu Marco , Justo Alfredo
Published: December 2011

Collections morphologically assignable to Volvariella dunensis from Sardinia and the Atlantic coast of Spain were revised and compared with the original collections. Molecular data supporting all examined collections as V. dunensis expand its known geographic distribution.
A revised morphological characterization and a phylogenetic analysis of all Volvariella species sequenced to date are provided.
Lepiota (Agaricales) in northern Thailand – 1. L. section Stenosporae
Authors: Sysouphanthong P. , Hyde K.D. , Chukeatirote E. , Bahkali A.H. , Vellinga E.C.
Published: December 2011

Eleven species of Lepiota section Stenosporae, reported as new for Thailand, are fully described and illustrated. Five are compared with European and North American collections based on nrITS sequence data. Two species possess a cutis-like pileipellis (L. aureofulvella,
L. sp. 2) and nine are characterized by a trichodermium (L. alopochroa, L. castanea, L. citrophylla, L. erythrosticta, L. griseovirens, L. infelix, L. papillata, L. poliochloodes , L. sp. 1). New to science are Lepiota aureofulvella (close to L. boudieri) and
L. papillata, which is characterized by small basidiomata covered with gray-brown to olive brown squamules, an orange-white to brownishorange context, spurred basidiospores with straight or outgrown base, clavate to cylindrical cheilocystidia, and a trichodermal pileus covering. A key
to Lepiota sect. Stenosporae in northern Thailand is provided.
Single-Suture Scleral Fixation of Subluxated Foldable Intraocular Lenses
Authors: Yarangumeli Alper , Alp Mehmet Numan , Kural Gulcan
Published: December 2011

Purpose

To evaluate the results of single-suture scleral fixation of subluxated foldable intraocular lenses (IOL) in eyes with sufficient residual capsular support.

Methods

The results of IOL repositioning by single-suture scleral fixation in 6 eyes of 6 patients with IOL subluxation were included. All subluxated IOLs were single-piece hydrophilic acrylic. Subluxation resulted from posterior capsule tears in 3 eyes, zonular dialyses in 2 eyes, and zonular dialysis with a capsulorhexis tear in 1 eye. A similar technique was used in all eyes in which one haptic was externalized through a superior clear corneal incision and tied with a Pair-PAK 10-0 polypropylene suture, and was finally retracted and fixated behind the iris close to the ciliary sulcus at the 12:00 meridian. All patients were followed up for at least 6 months.

Results

Best-corrected visual acuities ranged between finger counting and 20/70 (mean logMAR 1.02±0.64) preoperatively, and between 20/100 and 20/20 (mean logMAR 0.22±0.26) at the final postoperative visit. All IOLs remained centered and no significant postoperative complications were encountered except for an IOL tilt which resulted in a considerable oblique astigmatism in one eye.

Conclusions

Subluxated foldable IOLs may safely be repositioned and secured with a single scleral fixation suture in selected cases with adequate amount of capsular remnants.
Effects of Osteogenic Differentiation Inducers on in Vitro Expanded Adult Mesenchymal Stromal Cells
Authors: Fiorentini Elisa , Granchi Donatella , Leonardi Elisa , Baldini Nicola , Ciapetti Gabriela
Published: December 2011

Purpose

For bone regeneration therapy using stem cells, well-defined ex vivo protocols to expand mesenchymal stromal cells (MSC), as well as assays to show their potential differentiation into the osteogenic lineage, are needed. Aim of this study was to analyze the role of the biochemical osteogenic inducers, i.e. ascorbic acid, dexamethasone, and β-glycerophosphate, employed in the current protocols for osteogenic differentiation of MSC in vitro, to address the requirements for reliable differentiation systems.

Methods

MSC were isolated from the bone marrow of donors (46–73 years of age) undergoing total hip replacement, and expanded in vitro. At confluence, MSC were cultured under four different conditions: α-MEM plus serum (basal medium or C1), basal medium plus ascorbate (C2), basal medium plus ascorbate and dexamethasone (C3), or basal medium plus ascorbate, dexamethasone and β-glycerophosphate (C4). Morphology, proliferation, mineralization, alkaline phosphatase, collagen and expression of bone-related genes of MSC under the different media were analyzed at fixed time points.

Results

MSC proliferation and the number of colony forming units were increased by ascorbic acid, whereas dexamethasone enhanced the proportion of ALP-positive CFU and was critical for mineral deposition. Runx-2 and type I collagen gene expression decreased along with additive-induced MSC differentiation, i.e. from C1 to C4, while ALP and osteocalcin were differently regulated.

Conclusion

Our findings support the role of different inducers on the sequential stages of MSC expansion and osteogenic differentiation in vitro, suggesting the addition of DEX following proliferation to ensure mineralization, as an index of in vivo osteogenic potency of human mesenchymal cells.
Incidental Prenatal Diagnosis of Sex Chromosome Aneuploidies: Health, Behavior, and Fertility
Authors: Pieters J. J. P. M. , Kooper A. J. A. , van Kessel A. Geurts , Braat D. D. M. , Smits A. P. T.
Published: December 2011

Objective. To assess the diagnostic relevance of incidental prenatal findings of sex chromosome aneuploidies. Methods. We searched with medical subject headings (MeSHs) and keywords in Medline and the Cochrane Library and systematically screened publications on postnatally diagnosed sex chromosomal aneuploidies from 2006 to 2011 as well as publications on incidentally prenatally diagnosed sex chromosomal aneuploidies from 1980 to 2011. Results. Postnatally diagnosed sex chromosomal aneuploidies demonstrated three clinical relevant domains of abnormality: physical (22–100%), behavior (0–56%), and reproductive health (47–100%), while incidentally prenatally diagnosed sex chromosomal aneuploidies demonstrated, respectively, 0–33%, 0–40%, and 0–36%. Conclusion. In the literature incidental prenatal diagnosis of sex chromosomal aneuploidies is associated with normal to mildly affected phenotypes. This contrasts sharply with those of postnatally diagnosed sex chromosomal aneuploidies and highlights the importance of this ascertainment bias towards the prognostic value of diagnosis of fetal sex chromosomal aneuploidies. This observation should be taken into account, especially when considering excluding the sex chromosomes in invasive prenatal testing using Rapid Aneuploidy Detection.
Determination of Picogram Levels of Roxithromycin in Pharmaceutical, Human Serum, and Urine by Flow-Injection Chemiluminescence
Authors: Liu Jiangman , Yang Huan , Zhang Yun , Wu Min , Zhao Haixiang , Song Zhenghua
Published: December 2011

A sensitive chemiluminescence (CL) method, based on the inhibitory effect of roxithromycin (ROX) on the CL reaction between luminol and dissolved oxygen in a flow-injection system, was first proposed for the determination of ROX at picogram levels. The decrement of CL intensity was linearly proportional to the logarithm of ROX concentrations ranging from 0.1 to 100 pg mL-1, giving the limit of detection (LOD) of 0.03 pg mL-1(3σ). At a flow rate of 2.0 mL min-1, a complete analytical procedure including sampling and washing could be performed within 0.5 min, with relative standard deviations (RSDs) of less than 5.0% (n=5). The proposed procedure was applied successfully to the determination of ROX in pharmaceutical, human serum, and urine with the recoveries ranging from 90.0 to 110.0%.
Stability Studies of Clonazepam, Diazepam, Haloperidol, and Doxepin with Diverse Polarities in an Acidic Environment
Authors: Maślanka Anna , Krzek Jan , Stolarczyk Mariusz , Walczak Maria , Głogowska Agata
Published: December 2011

Stability of clonazepam, diazepam, haloperidol, and doxepin was determined in acidic solutions. In addition, determination of the kinetic and thermodynamic properties of this stability was carried out. Reaction rate constants (k), half-life times (t0.1 and t0.5), and activation energy (Ea) were estimated for the drugs, which differed in polarity expressed with log P values. It was observed that estimated E a values increased from 42.13 to 125.03 kJ/mol with an increase of lipophilicity (log P) beginning from the most hydrophilic drug (clonazepam, 2.70 log P) to the most lipophilic drug (doxepin, 4.10 log P). All degradation products were studied using an HPLC/electrospray ionization-MS technique in the positive ionization mode.
A Simple Method for Simultaneous Determination of Basic Dyes Encountered in Food Preparations by Reversed-Phase HPLC
Authors: Dixit Sumita , Khanna Subhash K , Das Mukul
Published: December 2011

The present method utilizes a simple pretreatment step, cleanup on polyamide SPE cartridges, and HPLC resolution on reversed-phase C18 for the detection of the three basic nonpermitted dyes encountered in food matrixes. Polyamide cartridges were chosen because both acidic and basic dyes can be cleaned up due to their amphoteric nature. Analysis was performed on a reversed-phase C18 μ-Bondapak column using the isocratic mixture of acetonitrile–sodium acetate with a flow rate of 1.5 mL/min and a programmable λmax specific visible detection to monitor colors, achieving higher sensitivity and expanded scope to test multicolor blends. All the colors showed linearity with the regression coefficient, from 0.9983 to 0.9995. The LOD and LOQ ranged between 0.107 and 0.754 mg/L and 0.371 and 2.27 mg/L or mg/kg, respectively. The intraday and interday precision gave good RSDs, and percentage recoveries in different food matrixes ranged from 75 to 96.5%. The study demonstrates that the use of a combination of a simple SPE cleanup and HPLC resolution with UV-Vis end point detection was successful in screening the presence of these three basic nonpermitted dyes individually or in blend, in a variety of food matrixes.
A New Cadmium Reduction Device for the Microplate Determination of Nitrate in Water, Soil, Plant Tissue, and Physiological Fluids
Authors: Crutchfield James D , Grove John H
Published: December 2011

A reusable catalytic reductor consisting of 96 copperized-cadmium pins attached to a microplate lid was developed to simultaneously reduce nitrate (NO3–) to nitrite (NO2–) in all wells of a standard microplate. The resulting NO2– is analyzed colorimetrically by the Griess reaction using a microplate reader. Nitrate data from groundwater samples analyzed using the new device correlated well with data obtained by ion chromatography (r2 = 0.9959). Soil and plant tissue samples previously analyzed for NO3– in an interlaboratory validation study sponsored by the Soil Science Society of America were also analyzed using the new technique. For the soil sample set, the data are shown to correlate well with the other methods used (r2 = 0.9976). Plant data correlated less well, especially for samples containing low concentrations of NO3–. Reasons for these discrepancies are discussed, and new techniques to increase the accuracy of the analysis are explored. In addition, a method is presented for analyzing NO3– in physiological fluids (blood serum and urine) after matrix modification with Somogyi's reagent. A protocol for statistical validation of data when analyzing samples with complex matrixes is also established. The simplicity, adaptability, and low cost of the device indicate its potential for widespread application.
Multiresidue Pesticide Analysis in Ginseng and Spinach by Nontargeted and Targeted Screening Procedures
Authors: Hayward Douglas G , Wong Jon W , Zhang Kai , Chang James , Shi Feng , Banerjee Kaushik , Yang Paul
Published: December 2011

Five different mass spectrometers interfaced to GC or LC were evaluated for their application to targeted and nontargeted screening of pesticides in two foods, spinach and ginseng. The five MS systems were capillary GC/MS/MS, GC-high resolution time-of-flight (GC/HR-TOF)-MS, TOF-MS interfaced with a comprehensive multidimensional GC (GCxGC/TOF-MS), an MS/MS ion trap hybrid mass (qTrap) system interfaced with an ultra-performance liquid chromatograph (UPLC-qTrap), and UPLC interfaced to an orbital trap high resolution mass spectrometer (UPLC/Orbitrap HR-MS). Each MS system was tested with spinach and ginseng extracts prepared through a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure. Each matrix was fortified at 10 and 50 ng/g for spinach or 25 and 100 ng/g for ginseng with subsets of 486 pesticides, isomers, and metabolites representing most pesticide classes. HR-TOF-MS was effective in a targeted search for characteristic accurate mass ions and identified 97% of 170 pesticides in ginseng at 25 ng/g. A targeted screen of either ginseng or spinach found 94–95% of pesticides fortified for analysis at 10 ng/g with GC/MS/MS or LC/MS/MS using multiple reaction monitoring (MRM) procedures. Orbitrap-MS successfully found 89% of 177 fortified pesticides in spinach at 25 ng/g using a targeted search of accurate mass pseudomolecular ions in the positive electrospray ionization mode. A comprehensive GCxGC/TOF-MS system provided separation and identification of 342 pesticides and metabolites in a single 32 min acquisition with standards. Only 67 or 81% of the pesticides were identified in ginseng and spinach matrixes at 25 ng/g or 10 ng/g, respectively. MS/MS or qTrap-MS operated in the MRM mode produced the lowest false-negative rates, at 10 ng/g. Improvements to instrumentation, methods, and software are needed for efficient use of nontargeted screens in parallel with triple quadrupole MS.
Applications of LC/ESI-MS/MS and UHPLC/Qq-TOF-MS for the Determination of 141 Pesticides in Tea
Authors: Wang Jian , Chow Willis , Leung Daniel
Published: December 2011

This paper presents the applications of LC-electrospray ionization (ESI)/MS/MS and ultra-HPLC (UHPLC)/ESI quadrupole (Qq)-time-of-flight (TOF) MS for the determination of 141 pesticides in tea. Pesticides were extracted and cleaned up from tea with a modified quick, easy, cheap, effective, rugged, and safe method using graphitized carbon black and primary-secondary amine sorbents. Quantification was achieved using matrix-matched standard calibration curves with isotopically labeled standards or a chemical analog as internal standards in an analytical range from 5 to 500 μg/kg. The LC/ESI-MS/MS served as a reliable tool to quantify the pesticides due to its superior sensitivity and good repeatability. Its method performance characteristics that include overall recovery, intermediate precision, and measurement uncertainty were evaluated according to a statistically designed experiment, i.e., a nested design. About 87% of the pesticides had recoveries between 81 and 110%; 94% had an intermediate precision ≤20%; and 90% showed measurement uncertainty ≤40%. About 92% of the pesticides were able to be detected at 5 μg/kg with an S/N ≥3. The UHPLC/Qq-TOF-MS showed much less sensitivity and poorer repeatability compared to the LC/ESI-MS/MS, and, therefore, it was primarily used for confirmatory purposes based on the accurate mass measurement and isotopic patterns.
Using the scan‐x Web Site to Predict Protein Post‐Translational Modifications
Authors: Chou Michael F. , Schwartz Daniel
Published: December 2011

The recent plethora of proteomic mass spectrometry data is providing evidence that almost every protein in the cell undergoes some form of post‐translational modification. We describe a protocol to use the scan‐x Web site to view predicted acetylation sites in the human proteome and predicted phosphorylation sites in the human, mouse, fly, and yeast proteomes with high specificity. This tool is accessible from virtually any computer with a Web browser. The only requirement is a means of searching for a protein of interest in one of the represented organisms. Curr. Protoc. Bioinform. 36:13.16.1‐13.16.8. © 2011 by John Wiley & Sons, Inc.
Arsenic: Inorganic ChemistryBased in part on the article Arsenic: Inorganic Chemistry by Ralph A. Zingaro which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Muñoz‐Hernández Miguel‐Ángel
Published: December 2011

This article reflects the importance and development of the chemistry of inorganic arsenic compounds. Throughout the text the reader will be taken from the chemistry of simple arsenic species found in minerals to such as those arsenic species that reflect the breath of modern inorganic chemistry. Efforts have been made to show developments in fundamental chemistry, materials science, and aspects of arsenic in the environment. Accordingly, Section 2 covers aspects of the preparation of simple arsenic species like the chalcogenides and halogenides. In Section 3 the important arsenic intermetallic and Zintl phases are discussed emphasizing important technological aspects. The chemistry of inorganic arsenic hydrides and halides is presented in Sections 4 and 5 with many important fundamental issues that are difficult to find in one single textbook. Inorganic simple arsenic compounds that bear pnictogen and/or chalcogen atoms are discussed in Sections 6 and 8. In these two sections the chemistry is presented starting from species that are found in minerals to complexes that have arsenic as the central atom introducing exciting discrete arsenic molecules and aspects of supramolecular chemistry. The chemistry of arsenic–carbon species where the carbon atom is strictly inorganic is shown in Section 7. Finally, Section 9 intends to give a brief introduction of the impact of arsenic in the environment, especially focusing on issues related to living organisms.
BiomineralizationBased in part on the article Biomineralization by Richard B. Frankel which appeared in the
Encyclopedia of Inorganic Chemistry, First Edition
.
Authors: Dauphin Yannicke
Published: December 2011

Three main categories are involved in biominerals: silica, calcium carbonates, and calcium phosphates. The calcium biominerals are usually crystalline, but amorphous types are also known. Within these categories, the shapes and chemical contents of structural units are variable. Moreover, the chemical and physical properties of biominerals are very different from the crystal habits produced inorganically: they depend on the producing plants and animals and the environmental conditions. Biomineral development is permanently controlled by specifically produced organic molecules that remain entrapped within the mineral units. Although biomineralization has been widely studied in the past, the growth mechanisms are still poorly understood, and the most elaborated model is based on the nacreous layer of mollusk shells. Studies on biominerals and biomineralization have various applications, from biology and geology to biomimetics.
Carbonyl Complexes of the Transition Metals
Authors: Calderazzo Fausto
Published: December 2011

Carbon monoxide is a versatile ligand as it forms compounds with both transition metals and main group elements. Transition d metals of electronic configuration dn(0 < n < 10) form the most numerous class of these compounds, although recent progress has been made in expanding the area of existence toward main group, lanthanide (4f) and actinide (5f) metals. The most extensively studied series of carbonyl derivatives have the general formula [M(CO)n]m, withnrepresenting the coordination number of the central metal atom M, andmbeing the nuclearity of the system. In these compounds, the central metal atom is in the zero oxidation state. Starting from readily available inorganic derivatives in a positive oxidation state, the synthesis of these compounds normally requires a reducing agent capable of acting in the presence of carbon monoxide: in fact, only nickel metal, as a finely divided activated powder, is reactive toward CO leading to the corresponding derivative Ni(CO)4. The selection of the reducing agent varies as a function of the position of the metal M within the periodic table. There is a general trend of an increase in the nuclearitymtoward the end of the transition d series, the nuclearity being related to the bonding arrangements of the CO ligand, which may act as terminal, doubly bridging or triply bridging. Metal carbonyls are characterized by IR‐active vibrations around 2000 cm−1associated with the carbonyl groups. Vibrational spectra in solution give important information about: (a) the electronic distribution within the M–CO bond in terminally bonded carbonyl groups; (b) the molecular structure associated with the number of bands observed; (c) the type of bonding in dinuclear or polynuclear compounds. X‐ray diffraction data have been extensively used in order to define the molecular structure in the solid state. The metal–CO combinations span a wide range of oxidation states, derivatives being known for oxidation states from +III to −IV. Metal carbonyls undergo three types of reaction: (a) substitution of the carbonyl groups, whereby the oxidation state of the central metal atom remains unchanged, (b) oxidation, and (c) reduction. Carbonyl derivatives of early‐ and late transition metals present specific bonding and spectroscopic properties. Concerning the transition elements of groups 6–9, the M–CO bond dissociation enthalpy increases down the group, and is normally greater than the metal–metal bond enthalpy, the latter being estimated from the heat of atomization. From a mechanistic viewpoint, substitution and redox reactions have been studied extensively. A special case of substitution is the migratory carbonyl insertion, by which an M–R bond to a carbyl group R is converted by CO into the M–(CO)R sequence.
Iron: Heme Proteins & Dioxygen Transport & StorageBased in part on the article Iron: Heme Proteins & Dioxygen Transport by Harold M. Goff which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Hayashi Takashi
Published: December 2011

Most organisms require dioxygen (O2) to survive; however, simple O2diffusion in blood does not supply a sufficient amount of oxygen for respiration. Thus, in all mammals, O2is carried and stored by O2‐binding heme proteins, myoglobin, and hemoglobin. Myoglobin is a single‐chain globular protein with heme as a prosthetic group, while hemoglobin consists of four heme‐containing subunits. O2binds to ferrous pentacoordinated heme‐iron and is stabilized by distal and proximal amino acid residues in the heme pocket. The O2pathway in the protein matrix and the binding mechanisms are discussed in detail by O2‐binding kinetic data for a series of myoglobin and hemoglobin mutants. Particularly, several residues, B10, E7, E10, E11, F7, and F8, mainly regulate the O2binding in the vertebrate heme proteins. In contrast, invertebrate and plant hemoglobins with unusually high O2affinities have been found in nature. InAscarishemoglobin, O2dissociation is very slow, whereas leghemoglobin shows a large O2association rate constant. In the case of trematode hemoglobin fromParamphistonum epiclitum, both kinetic parameters are improved. Artificial molecular design to modify O2affinity is another way to understand the O2binding mechanisms of the heme proteins. The strategy of heme protein modification can be divided into at least two approaches: One is a point mutation at distal or proximal amino acid residues, and the other is reconstitution by replacement of the native heme with an artificial heme. The physiological function of vertebrate hemoglobins is O2transport from the lungs or gills to the tissues; thus, they are required to exhibit cooperative interactions in binding O2to heme‐iron in the protein matrix. Although it is well known that a Hill coefficient of approximately 3.0 has been observed for tetrameric human hemoglobin, the mechanism of allosteric interaction is still discussed based on theoretical and experimental data. At present, an a two‐state (MWC) model proposed by Monod, Wyman, and Changeux for cooperative ligand binding is preferred to a sequential model. In addition, a study on the allosteric effectors for hemoglobins seems to be attractive from physiological aspects. The conventional effectors such as organic polyphosphate for human hemoglobin reduce the O2affinity of the T‐state, while it has been found that bezafibrate (BZF) or inositol hexaphosphate (IHP) can regulate O2binding not only for the T‐state but also for the R‐state. Finally, the interaction of NO with the heme proteins and modification of myoglobin for conversion into a new oxidase are briefly described.
Nitrogen Monoxide (Nitric Oxide): Bioinorganic Chemistry
Authors: Lancaster Jack R. , Giles Gregory I.
Published: December 2011

In only the last 20 years, Nitric oxide (NO, nitrogen monoxide), one of the smallest and simplest molecules in Nature, has been found to be involved in an astounding number of mammalian physiological and pathophysiological phenomena. The importance of NO as a messenger molecule in the cardiovascular system was recognized in 1998 by the awarding of the Nobel Prize in Physiology or Medicine and over 70000 papers have appeared involving NO in biology. The simplicity of its chemical structure stands in stark contrast to the complexity of its biological actions, including its “Janus‐faced” character as both beneficial and detrimental. This chapter is an overview of the history of this discovery, the fundamental chemistry of NO and its derivatives in the biological environment, and the multiple biological actions of NO.
Alkane Carbon–Hydrogen Bond Activation
Authors: Crabtree Robert H.
Published: December 2011

The title topic is reviewed with attention to alkane complexes, Shilov chemistry, alkane functionalization, Fenton reagents, oxidative addition pathways, sigma bond metathesis pathways, and surface‐bound reagents. Methane to methanol chemistry is discussed and attempts to commercialize the reaction are described in connection with Periana systems. Some organic synthetic applications are also covered. Future challenges are posed.
Nuclear Magnetic Resonance (
NMR
) Spectroscopy of Metallobiomolecules
Authors: Bren Kara L.
Published: December 2011

Nuclear magnetic resonance (NMR) spectroscopy provides information on the structure and dynamics of metallobiomolecules at atomic resolution. A range of metal‐binding sites in biomolecules can be studied by NMR, although the methods used require consideration of the properties of the metal site. Diamagnetic metal‐binding sites are probed using conventional NMR approaches appropriate for analyzing interactions between ions and macromolecules. Weak metal binding as is common in RNAs may require use of mimics that bind more strongly and/or that provide a specific spectroscopic handle. Paramagnetic metals induce hyperfine shifting and linebroadening that serve as signals of metal binding, but may also require adjustments to standard NMR methodologies. Hyperfine shifting takes place through scalar or dipolar mechanisms, and these effects in turn reveal details of metal site structure and metal electronic structure. Paramagnetic effects on chemical shifts are also used to refine structures of metallobiomolecules. Resonance broadening resulting from the hyperfine interaction is related to unpaired electron–nucleus distance as well as properties of the metal ion and thus can be a restraint on structure. The high magnetic anisotropy of some paramagnetic biomolecules can cause the molecule to take a preferential orientation within the applied magnetic field to allow observation of residual dipolar couplings, which reveal relative angular orientations of bond vectors. The study of the many effects of paramagnetic centers on NMR spectra has advanced the field of biomolecular solution structure determination as these efforts have introduced new restraints used in calculating structures. NMR is also valuable for analyzing biomolecule dynamics and chemical exchange processes. A related application is analysis of interactions between metallobiomolecules and ligands, or other macromolecules. Application of NMR to metallobiomolecules has provided a means to study phenomena difficult to observe using other methods such as interactions between proteins, electron self‐exchange reactions, and biomolecule dynamics over a wide range of time scales. NMR methodology continues to advance rapidly and is expected to continue to exert a large influence on our understanding of metal sites in biomolecules.
Nano/Microporous Materials: Transition Metal Cyanides
Authors: Lu Tong‐Bu , Collins David J. , Zhou Hong‐Cai
Published: December 2011

Transition metal–cyanide clusters, in which the cyanide anion acts as a bridging ligand, exhibit a rich variety of shapes and sizes, from simple squares to high‐nuclearity cubes and octahedra. Clusters may be homometallic or heterometallic, and a significant fraction of the transition metals are represented among these materials. Magnetic coupling in these clusters is widespread owing to the proximity of the metals and short length of the bridging cyanide. This review examines the structures and magnetic properties of the major types of transition metal–cyanide cluster materials.
Inorganic Nanocrystals: Patterning and Assembling
Authors: Curri Maria Lucia , Comparelli Roberto , Striccoli Marinella , Depalo Nicoletta , Fanizza Elisabetta
Published: December 2011

Recently, increasing interest has been devoted to the study of the size‐dependent properties of inorganic nanocrystals and nanoparticles, in order to investigate and exploit their original potential. The ability to access nanoparticle properties for device fabrication is based on their organization in morphologically controlled assembly and/or ordered arrays, with suitable patterning, in order to bridge the gap between nanoscopic and mesoscopic scale.

Assembly procedures allow the formation of original ordered state of matter and the fabrication of 2‐/3‐D patterned micro‐ and nanostructure, representing a promising route for producing functional materials and for processing and integrating the nanoparticles in macroscopic systems to fully develop their unprecedented functionality for materials and devices for biomedical, electronic, catalytic, and separation process technologies. Top‐down technological methods and techniques, conventional and emerging, have been cleverly and ingenuously combined and matched with dedicated bottom‐up approaches, paying attention to the peculiarity of the nanoparticle size regime. In most approaches, a precise control on the size and shape of the nanoparticles is crucial for driving the assembling and the extent to which the building blocks can be engineered, designed, and fabricated with desired features, including encoded instructions for assembling, has been greatly progressing in the last years. This article focuses on the potential of exploitation of inorganic nanocrystals and nanoparticles for assembling. An overview of the inorganic nanocrystal functions in the different and complementary strategies is outlined, highlighting the novelty and originality of the specific results and placing them in the scenario of the emerging material science, toward the envisioned creation of materials by design.
Quantum‐Chemistry‐Centered Normal Coordinate Analysis (
QCC
‐
NCA
): Application of
NCA
for the Simulation of the Vibrational Spectra of Large Molecules
Authors: Lehnert Nicolai
Published: December 2011

Vibrational spectroscopy is a powerful spectroscopic method that provides detailed information about the geometric and electronic structural properties of materials, compounds, and biomolecules. In the case of transition‐metal complexes, for example, vibrational spectra allow for the determination of the oxidation and spin state of the metal. In addition, vibrational spectroscopy is of great value in monitoring the binding and activation of small molecules, especially diatomics X–Y (O
2
, N
2
, CO, NO, etc.) and their derivatives, by transition‐metal complexes. Here, the coordination, reduction, protonation, derivatization, etc., of the diatomic can be monitored via the X–Y and metal‐XY bond strengths. Usually, the corresponding X–Y and metal‐XY vibrational frequencies are used for such correlations. This, however, is problematic because the energies of normal modes in general do not correlate directly with bond strengths, as they also depend on mode mixing and atomic masses. Because of this, it is much better to compare the X–Y and metal‐XY force constants along a reaction coordinate or between different species to identify chemically important changes/differences in bond strengths. This poses one problem: force constants are obtained from normal coordinate analysis (NCA), but how can this type of analysis be performed routinely for large molecules with many vibrational degrees of freedom, especially if the interest is focused on a small subunit of the molecule (the metal‐XY bond), whereas the other organic ligands L of the metal are of limited interest? The quantum chemistry centered normal coordinate analysis (QCC‐NCA) provides a solution to this problem by using density functional theory (DFT) calculations to generate an initial force field, followed by refinement of the limited number of force constants of the metal‐XY subunit only, whereas all other force constants remain unchanged. The available QCC‐NCA software allows one to perform this kind of analysis with minimal effort. This article provides a general introduction to the QCC‐NCA method and the underlying principles of vibrational analysis, combined with illustrative examples for applications from the area of the transition‐metal mediated activation of N
2
, O
2
, and NO. Special focus is put on the electronic structures and reactivities of ferrous‐heme nitrosyls, where the Fe–NO and N–O force constants have provided key insight into the activation of NO as a function of the trans ligand. The latest development with respect to the QCC‐NCA method is the calculation of nuclear resonance vibrational spectroscopy (NRVS) intensities, which is described in the final sections of this article.
Reaction Coordinate of Pyranopterin Molybdenum Enzymes
Authors: Kirk Martin L. , Knottenbelt Sushilla , Habtegabre Abebe
Published: December 2011

Spectroscopic studies on two pyranopterin molybdenum enzymes, sulfite oxidase and xanthine oxidase, have been used to evaluate the results of detailed bonding calculations and provide insight into the reductive half reaction of these enzymes. Specifically, the nature of the reaction coordinate with respect to substrate oxidation appears to be under orbital control, with the inherent electronic structure of the active site playing a key role in the reactivity of these metalloenzymes.
Nature of the Catecholate—
Fe
(
III
) Bond: High Affinity Binding and Substrate Activation in Bioinorganic Chemistry
Authors: Solomon Edward I. , Pau Monita Y. M. , Hocking Rosalie K.
Published: December 2011

Catecholate‐Fe(III) (high‐spin) bonds are important in many areas of bioinorganic chemistry. These exhibit low‐energy, intense ligand‐to‐metal charge transfer (LMCT) transitions reflecting highly covalent bonds. This high covalency can make a major contribution to function. In this review, we develop the method of metal L‐edge X‐ray absorption spectroscopy (XAS) as a probe of differential orbital covalency (DOC), the amount of ligand character in the different d orbitals of a metal site in a highly covalent environment. We then apply this method to experimentally determine the covalency of the ligand‐metal bonds related to the siderophores and computationally evaluate this contribution to their high stability constants. We then use variable‐temperature, variable‐field, magnetic circular dichroism (VTVH MCD) spectroscopy to assign the LMCT transitions of the catecholate‐, substrate‐bound Fe
III
site of the intradiol dioxygenases. A reaction coordinate is presented where this charge transfer can overcome the spin‐forbidden nature of the reaction of the bound catecholate (singlet) with dioxygen (triplet).
Selenium: Radionuclides
Authors: Shaw George , Ashworth Daniel
Published: December 2011

Selenium in the environment has been studied intensively for several decades, since it is both a trace nutrient and a toxin. It is a ubiquitous element in soils, waters, and the atmosphere, with chemical similarities to the other group 16 elements sulfur, polonium, and tellurium. Important selenium species in environmental media include inorganic oxyanions as well as organic species produced by biological methylation mechanisms. The only probable long‐term source of radioactive selenium to the environment is the leakage from radioactive waste repositories. Only79Se is of concern in this respect, since it is the only long‐lived radioactive isotope of selenium (physical half‐life = 377 000 years). Under alkaline geochemical conditions, there is the potential for79Se to migrate from geological radioactive waste repositories in very small quantities over very long periods. It is expected that any79Se released into the environment will behave in the same way as nonradioactive selenium, though the kinetics of isotopic exchange between79Se and stable selenium in soils, sediments, and other environmental media have never been studied over timescales relevant to radioactive waste disposal. It is unlikely that environmental concentrations of79Se will ever lead to exposures approaching the intake levels associated with stable selenium. Any exposure that does occur is likely to be primarily through the dietary intake pathway, since the principal environmental reservoirs, and therefore potential sources, of selenium in the environment are waters and soils.
Thorium: Radionuclides
Authors: Wan Mahmood Zal Uyun , Rahim Mohamed Che Abd
Published: December 2011

Thorium is composed of 25 different isotopes with the common ones being
224
Th,
226
Th,
227
Th,
228
Th,
229
Th,
230
Th,
231
Th,
232
Th,
233
Th, and
234
Th. These decay with considerably different half‐lives and nuclear properties. Although thorium is considered one of the more highly radiotoxic elements, its toxicity is low because of its stability at ambient temperature. The intake of thorium isotopes by human being occurs mainly through animal products, cereals, vegetables, and waters. Thorium is widely distributed in small amounts, with an average lithospheric concentration of 8–12 mg g
−1
in the earth's crust (at an average concentration of 6 mg g
−1
in soil). Furthermore, thorium is quite useful, especially in industries, and it is also recognized as a potential fuel for fast breeder reactors, where it is converted to fissile
233
U. This article presents details on the occurrence, chemistry, speciation, separation, and analytical characterization techniques of the more common isotopes of thorium.
B
altic
S
ea: Radionuclides
Authors: Nielsen Sven P. , Lüning Maria , Ilus Erkki , Outola Iisa , Ikäheimonen Tarja , Mattila Jukka , Herrmann Jürgen , Kanisch Günter , Osvath Iolanda
Published: December 2011

The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s. Radioactivity inputs into the Baltic Sea from nuclear reprocessing plants in Western Europe have become of minor importance due to significant reduction of discharges in recent years. In terms of input of
137
Cs into the Baltic Sea, Chernobyl fallout has contributed about 82% and nuclear weapons test fallout about 14%. For
90
Sr in the Baltic Sea, input from atmospheric fallout from nuclear weapons tests has contributed about 81%, while the contribution from Chernobyl fallout was about 13%. Cesium‐137 is the main indicator of Baltic seawater with respect to anthropogenic radioactivity. The highest concentrations in seawater during 1999–2006 were found in the Baltic Proper and the Bothnian Sea. The general trend is steadily decreasing. Concentrations of anthropogenic radioactivity in fish generally show decreasing trends in agreement with concentrations in seawater. Among freshwater fish, pike showed large
137
Cs values due to their higher concentration factors (CFs). The larger
137
Cs values of pike were observed at the coast of the Bothnian Sea. The Baltic Sea is the regional sea in the world with the highest concentrations of
137
Cs. The Baltic Sea ranks third in the world with respect to
90
Sr in seawater; only the Irish Sea and the Black Sea show higher levels. In 1990, average concentrations of
137
Cs in fish from the Baltic Sea were similar to those in the Irish Sea, about 4 times higher than in the Black Sea and about 30 times higher than in the Mediterranean Sea.