bluuebunny/crossref_metadata_2025 huggingface dataset:
The Structural Implications of a Unilateral Facial Skeletal Cleft: A Three-Dimensional Finite Element Model Approach
Authors: Zhao Linping , Herman Jean E. , Patel Pravin K.
Published: March 2008

Objective:

For children born with a unilateral facial skeletal cleft, oral motor function is impaired and skeletal development and growth are asymmetrical with regard to the midsagittal plane. This study was designed to verify that a unilateral skeletal cleft and its dimensions (i.e., depth and width) affect the severity of the asymmetric stress and strain distribution within the maxilla.

Methods:

A three-dimensional finite element model of a normal maxilla was developed from pediatric, subject-specific computerized tomography scan data. A clefting pattern then was introduced to simulate varying degrees of deformity in geometry, with the bone properties and boundary conditions held constant. The asymmetric index was introduced to quantify the asymmetrical stress and strain distribution within the maxilla with regard to the midsagittal plane.

Results:

The unilateral skeletal cleft led to a nonuniform, asymmetric stress and strain distribution within the maxilla: intensified on the noncleft side and weakened on the cleft side. As the depth of the unilateral cleft increased, the stress and strain distribution became increasingly asymmetric as measured by the asymmetric index. In contrast, the width of the cleft had minimal effect on the asymmetrical stress and strain distribution.

Interpretation/conclusion:

These results implied that a child born with a unilateral cleft would be expected to have an asymmetric skeletal development between the noncleft and the cleft sides as a consequence of an asymmetric functional loading pattern.
Detection of permanent open water surfaces in central Siberia with ENVISAT ASAR wide swath data with special emphasis on the estimation of methane fluxes from tundra wetlands
Authors: Bartsch Annett , Pathe Carsten , Wagner Wolfgang , Scipal Klaus
Published: March 2008

Permanent water bodies not only store dissolved CO2 but are essential for the maintenance of wetlands in their proximity. From the viewpoint of greenhouse gas (GHG) accounting wetland functions comprise sequestration of carbon under anaerobic conditions and methane release. The investigated area in central Siberia covers boreal and sub-arctic environments. Small inundated basins are abundant on the sub-arctic Taymir lowlands but also in parts of severe boreal climate where permafrost ice content is high and feature important freshwater ecosystems. Satellite radar imagery (ENVISAT ScanSAR), acquired in summer 2003 and 2004, has been used to derive open water surfaces with 150 m resolution, covering an area of approximately 3 Mkm2. The open water surface maps were derived using a simple threshold-based classification method. The results were assessed with Russian forest inventory data, which includes detailed information about water bodies. The resulting classification has been further used to estimate the extent of tundra wetlands and to determine their importance for methane emissions. Tundra wetlands cover 7% (400 000 km2) of the study region and methane emissions from hydromorphic soils are estimated to be 45 000 t d−1 for the Taymir peninsula.
The Effect of Coil Configuration on Run Length of Thermal Cracking Reactors
Authors: Karimzadeh Ramin , Hematian Amin , Omidkhah Mohammad Reza
Published: March 2008

Various parameters such as type of feedstock, inlet and outlet coil temperature, heat flux and residence time, affect the performance of a thermal cracking reactor. The pyrolysis coil configuration is one of the most important parameters which affects the performance of the reactor.In this research the effect of four different coil configurations, namely single row, millisecond, split and reversed split have been studied on run length, product yields, outside surface temperature of coil, coke deposition as well as temperature and pressure distribution. The reactor under investigation is the thermal cracker of Abadan petrochemical complex which uses propane as feedstock. The results show that millisecond coil configuration has the highest yield of ethylene and lowest coke thickness. However, it exhibits the lowest run length and worst ratio of length to diameter conditions. On the other hand, single row coil configuration has the lowest ethylene yield and highest coke thickness but, the highest run length with the lowest pressure drop also belongs to this coil configuration. It also presents the most even distribution of pressure and a linear temperature profile across the coil length, favoring better selectivity.
Evaluating the Demsetzian Trend in Copyright Law
Authors: Frischmann Brett M.
Published: March 2008

Copyright law provides an excellent case study with which to evaluate Harold Demsetz's theory of property rights. Regardless of how one feels about the relationship between property and intellectual property, it is hard to escape the fact that intellectual property rights have expanded and grown more property-like and more privatized in recent decades. In this article, I critique the undeniable Demsetzian trend in copyright law and challenge some of the fundamental premises upon which rest the normative arguments for continued privatization and propertization of intellectual resources. First, I focus on the perceived benefits of internalizing externalities, arguing that externalities do not necessarily distort incentives or, more generally, the market allocation of resources. For many externalities, there is no efficiency benefit to internalization (whether accomplished by Pigouvian taxes/subsidies or property rights). In the end, the benefits of internalization must be carefully assessed rather than assumed. The view that increasing the degree of internalization through private property rights inevitably leads to increased incentives to invest in creation or distribution is not well-established in either theory or practice. Second, I focus on the frequently-invoked solution of efficient licensing and the “logic” that property rights should be extended “into every corner in which people derive enjoyment and value...[so that] signals of consumer preference [may] trigger and direct [producers'] investments” (Goldstein, 1994). I argue that a fundamental flaw in this logic undermines the efficient licensing hypothesis. Social demand for individuals' access to and use of copyright protected works often exceeds private demand. Purchasers'/licensees' willingness to pay reflects only their private demand and does not take into account value that others might realize as a result of their use. As I explain, many uses of copyrighted works generate value for third-parties. Finally, drawing from the first two points, I argue that, from a Coasean perspective, both externalities and property rights have symmetrical and reciprocal potentials to distort the market allocation of resources. A priori and devoid of context, one cannot say that the potential distortions caused by a property right, externality, or incremental change in a property right have a net positive or negative effect on social welfare.
Sequencing-Based Genotyping and Association Analysis of the MICA and MICB Genes in Type 1 Diabetes
Authors: Field Sarah F. , Nejentsev Sergey , Walker Neil M. , Howson Joanna M.M. , Godfrey Lisa M. , Jolley Jennifer D. , Hardy Matthew P.A. , Todd John A.
Published: March 2008

OBJECTIVE— The nonclassical major histocompatibility complex (MHC) class I chain-related molecules (MICs), encoded within the MHC, function in immunity. The transmembrane polymorphism in MICA (MICA-STR) has been reported to be associated with type 1 diabetes. In this study, we directly sequenced both of the highly polymorphic MIC genes (MICA and MICB) in order to establish whether they are associated with type 1 diabetes independently of the known type 1 diabetes MHC class II genes HLA-DRB1 and HLA-DQB1.

RESEARCH DESIGN AND METHODS— We developed a sequencing-based typing method and genotyped MICA and MICB in 818 families (2,944 individuals) with type 1 diabetes from the U.K. and U.S. (constructing the genotype from single nucleotide polymorphisms in exons 2–4 of MICA and 2–5 of MICB) and additionally genotyped the MICA-STR in 2,023 type 1 diabetic case subjects and 1,748 control subjects from the U.K. We analyzed the association of the MICA and MICB alleles and genotypes with type 1 diabetes using regression methods.

RESULTS— We identified known MICA and MICB alleles and discovered four new MICB alleles. Based on this large-scale and detailed genotype data, we found no evidence for association of MICA and MICB with type 1 diabetes independently of the MHC class II genes (MICA P = 0.08, MICA-STR P = 0.76, MICB P = 0.03, after conditioning on HLA-DRB1 and HLA-DQB1).

CONCLUSIONS— Common MICA and MICB genetic variations including the MICA-STR are not associated, in a primary way, with susceptibility to type 1 diabetes.
Retinal and Cerebral Microvascular Signs and Diabetes
Authors: Qiu Chengxuan , Cotch Mary Frances , Sigurdsson Sigurdur , Garcia Melissa , Klein Ronald , Jonasson Fridbert , Klein Barbara E.K. , Eiriksdottir Gudny , Harris Tamara B. , van Buchem Mark A. , Gudnason Vilmundur , Launer Lenore J.
Published: March 2008

OBJECTIVE—Diabetes increases the risk for microvascular disease. The retina and the brain both have intricate microvascular systems that are developmentally similar. We sought to examine whether microvascular lesions in the retina and in the brain are associated and whether this association differs among people with and without diabetes.

RESEARCH DESIGN AND METHODS—The analysis included 4,218 participants of the Icelandic population-based Age, Gene/Environment Susceptibility-Reykjavik Study who were born in 1907–1935 and who were previously followed as a part of the Reykjavik Study. Retinal focal arteriolar narrowing, arteriovenous (AV) nicking, and microaneurysms/hemorrhages were evaluated on digital retinal images of both eyes. Cerebral microbleeds (CMBs) were evaluated from magnetic resonance images. Data were analyzed with logistic and multinomial logistic regression models controlling for demographics, major cardiovascular risk factors, cerebral infarcts, and white matter lesions.

RESULTS—Evidence of brain microbleeds was found in 485 (11.5%) people, including 192 with multiple (≥2) microbleeds. Subjects with signs of retinal microvascular lesions were at a significantly increased likelihood for having multiple CMBs. People with diabetes in combination with the presence of either retinal AV nicking (odds ratio [OR] 2.47 [95% CI 1.42–4.31]) or retinal microaneurysms/hemorrhages (2.28 [1.24–4.18]) were significantly more likely to have multiple CMBs.

CONCLUSIONS—Retinal microvascular abnormalities and brain microbleeds may occur together in older adults. People with both diabetes and signs of retinal microvascular lesions (AV nicking and microaneurysms/hemorrhages) are more likely to have multiple microbleeds in the brain. Microvascular disease in diabetes extends to the brain.
Statistical thermodynamic approach to molten Fe–Cr–P
Authors: Shohoji Nobumitsu , Figueiredo Marques Sofia
Published: March 2008

Statistical thermodynamic analysis was applied to the available phosphorus solubility data set for molten Fe1 – y
Cr
y
P
x
given as functions of Cr composition y, temperature T and phosphorus activity a(P) under the assumption that the solubility limit x of P in the molten Fe1-y
Cr
y
was 0.50 irrespective of y. The evaluated values of the energy parameter representing the extent of stability of P atoms in the molten Fe1 – y
Cr
y
P
x
showed an apparently realistic variation pattern with y for the level of y up to 0.465. Further, it was demonstrated by an interpolating estimation using the obtained statistical thermodynamic parameter values at two known levels of y that a(P) vs. x relationships for arbitrary y at specified T could be derived with acceptable accuracy.
Phase diagram of the iron-rich portion in the iron–gallium–aluminum ternary system
Authors: Zhou Yan , Wang Bowen , Li Shuying , Huang Wenmei , Cao Shuying
Published: March 2008

The isothermal section at 650°C and the vertical section Fe-(Ga0.75Al0.25) of the Fe-rich portion in the Fe – Ga – Al ternary system were determined using optical microscopy, scanning electron microscopy, energy dispersion X-ray spectroscopy, X-ray diffraction and differential thermal analysis. The isothermal section of the Fe-rich portion consists of 4 single-phase regions: A2, B2, D03, D019, and 4 two-phase regions: A2 + B2, A2 + D03, D03 + D019 and B2 + D019. No fcc L12 phase region occurs in the isothermal section of the Fe-rich portion. The vertical section Fe-(Ga0.75Al0.25) of the Fe-rich portion consists of 3 single-phase regions: A2, B2 and D03, 4 two-phase regions: A2 + D03, D03 + D019, A2 + L12 and D03 + L12, and 2 three-phase regions: D03 + D019 + L12 and A2 + D03 + L12.
Formation and microstructure of (Ti, V)C-reinforced iron-matrix composites using self-propagating high-temperature synthesis
Authors: Chrysanthou Andreas , Modi Om Prakash , Han Li , Ramakrishnan Narayanrao , O’Sullivan James M.
Published: March 2008

The combustion synthesis of (Ti, V)C-reinforced iron-matrix composites from elemental powders was examined. Examination using scanning electron microscopy indicated that two types of carbide particles were formed having a different size and composition from each other. These were sub-micron size (Ti, V)C particles and pure TiC or TiC-rich particles of a slightly larger particle size. The development of the microstructure and formation of the two types of carbides were explained through an understanding of the reaction mechanism and the thermodynamics of the carbide phases. Increasing the amount of vanadium in the reactants led to a decrease in the carbide and the iron grain size and to a corresponding increase in microhardness.
Phase transition in the Fe–V system
Authors: Boutarek Naïma , Mansour Samir , Amara Sif Eddine , Kesri Rafika
Published: March 2008

Fe – V binary alloys with different vanadium concentrations (4 to 55 at.%) are arc melted and systematically characterized by means of; (1) differential thermal analysis, (2) optical and scanning electron microscopy coupled to an energy dispersive X-ray microprobe analysis, (3) quantitative X-ray fluorescence spectrometry, and (4) X-ray diffraction.

The present work exhibits the solidification sequences according to the observed microstructures for Fe – V synthesis alloys. For the first time, a metastable -phase was observed in Fe rich alloy (4 at.% V). The phase transition is clearly shown. It takes place at 1320°C for the alloy V1 (4 at.% V).

For higher vanadium contents (55 at.% V maximum), the -phase is no longer observable. The phase transition is also shown. The -phase precipitates directly by a congruent reaction from the -solid solution. It occurs at 1090°C for the alloy V3 (25 at.% V) and increases with the vanadium content (ranging from 25 to 55 at.% V). These results are plotted on the accepted Fe – V phase diagram.
Mössbauer Spectroscopy
Authors: Schünemann Volker , Paulsen Hauke
Published: March 2008

Mössbauer spectroscopy offers information about the structural, electronic, and dynamic properties of Mössbauer‐active isotopes. Within this contribution we will limit ourselves to57Fe Mössbauer spectroscopy and discuss how electronic and structural information of iron centers in inorganic and bioinorganic compounds as well as iron proteins can be obtained. An introduction to the basic principles and necessary sample requirements is followed by examples of Mössbauer spectroscopic work on metallic iron, iron nanoparticles, and thin films. The main part of this contribution contains an overview of selected examples of iron compounds in almost all oxidation states known so far, ranging from zero‐valent iron carbonyls to very recently reported ultra‐high‐valent Fe(VI) coordination compounds. In addition, a short overview on the theoretical calculation of Mössbauer parameters like isomer shift and quadrupole splitting by means of density functional theory is given. These calculations have been improved considerably in recent years and are expected to be used by an increasing number of inorganic chemists for the interpretation of spectroscopic results.
Magnetic Circular Dichroism (
MCD
) Spectroscopy
Authors: Mack John , Stillman Martin J.
Published: March 2008

Magnetic circular dichroism (MCD) spectroscopy provides information about the spin and orbital angular momenta associated with ground and excited electronic states. This can provide the key to understanding the optical spectroscopy of high symmetry ions and complexes, which provides an important insight into the electronic structure. MCD spectra contain the same set of spectral bands as the corresponding electronic absorption spectrum, with significantly different band morphologies due to the effect of the applied magnetic field and the use of a differential absorbance intensity scale.

MCD spectra are recorded by mounting a superconducting magnet (
B
 ≈ 0–11 T), an electromagnet (
B
 ≈ 0–1 T), or a permanent magnet into the sample compartment of a CD spectrometer with the field applied parallel to the axis of light propagation. Parallel applied fields are often referred to as the Faraday magnet alignment, since it formed the basis of Faraday's pioneering experiments in which plane polarized beams of light were found to be rotated during transmission through certain substances, due to the differential absorbance of left circularly polarized (lcp) and right circularly polarized (rcp) light. The Faraday 𝒜

1

, ℬ

0

, and 𝒞

0

terms form the basis for the analysis of MCD spectra based on the Zeeman splitting of the absorption bands for lcp and rcp light, the field‐induced mixing of zero‐field states, and the Zeeman splitting‐based ground state population adjustment, respectively.
Nuclear Magnetic Resonance (NMR) Spectroscopy of Inorganic/Organometallic Molecules
Authors: Iggo Jonathan A. , Liu Jianke , Khimyak Yaroslav Z.
Published: March 2008

NMR spectroscopy is an indispensable spectroscopic tool for the characterization of inorganic compounds. This contribution provides a guide to the application of recent advances in high‐resolution, solid‐state, and high‐pressure NMR spectroscopic methods to organometallic/inorganic molecules and solids. The topics covered include methods for the determination of structure, intermolecular interactions, solid‐state organization, reaction kinetics, and diffusion.
Nuclear Quadrupole Resonance (NQR) Spectroscopy
Authors: Wulfsberg Gary P.
Published: March 2008

The article concerns the usefulness of nuclear quadrupole resonance (NQR) spectroscopy in inorganic and organometallic chemistry. NQR‐active nuclei have spinI ≥ 1; those of high enough abundance to be commonly useful are found in the odd‐numbered groups of the periodic table. These are tabulated and examples given for each. The number of NQR frequencies observed in a solid‐state compound reflects the number of chemically different quadrupolar atoms in the compound and also the number of crystallographically inequivalent atoms; changes in the latter may indicate phase transitions or different polymorphs of a given compound. More commonly, one uses average NQR frequencies for chemically different atoms, and from these average frequencies, derives atomic parameters such as populations of valence orbitals, partial ionic charges, π‐bond orders, and covalent bond orders of the quadrupolar atom. The article mainly reviews selected applications of halogen (35Cl,79, 81Br,127I) NQR to specific bonding questions in inorganic chemistry, and divides these according to whether the halogen or other atoms are (a) single bonded, (b) single bonded but with secondary bonds with other atoms, or (c) bonded to several atoms. For singly bonded atoms, the applications reviewed include (a1) relativistic effects, (a2) effects of nearby ionic charges on haloacetate ions, (a3) the contrasting effects of nearby ionic charges on halometallate ions, (a4) effects of intramolecular partial charges on chlorines in organosilicon compounds, (a5) cis‐and trans‐ ligand effects in substituted halometallate complexes, and (a6) interpretations of multicentered bonding in trihalide ions. Secondary bonding of single‐bonded halogen atoms are reviewed particularly in the cases of (b1) halocarbons as ligands, (b2) chloroacetates and chlorophenolates as chlorine‐donor ligands, and (b3) in salts of weakly coordinated halogenated anions. Finally, some illustrations are given of NQR studies of central multicoordinated atoms (for example, transition‐metal atoms in complexes).
X‐Ray Absorption Spectroscopy
Authors: Bencze Krisztina Z. , Kondapalli Kalyan C. , Stemmler Timothy L.
Published: March 2008

X‐ray absorption spectroscopy (XAS), often referred to as X‐ray absorption fine structure (XAFS) spectroscopy, is a powerful technique available for determining the local coordination site structure and electronic properties of specific atoms in molecules. XAS can be performed on molecules in the gaseous, solution, or solid states, and generally every element is spectroscopically active. This technique utilizes high intensity X rays supplied by synchrotron radiation sources to selectively excite core electron transitions for a specific element of choice. XAS spectra are divided into two spectral regions, the X‐ray absorption near edge structure (XANES) region and the extended X‐ray absorption fine structure (EXAFS) region. XANES spectra can be utilized to provide: (1) qualitative information regarding the ligands coordinated to the absorbing atom, (2) semi‐quantitative information regarding the redox state of the absorbing atom, and (3) metal‐ligand coordination geometry. Simulations of the EXAFS data can provide information regarding absorber‐scatterer bond length values to extremely high accuracy (ca. ±0.02 Å), as well as coordination numbers and ligand identity at reduced accuracies. The high accuracy in bond lengths achieved from XAS makes this technique extremely sensitive for measuring subtle structural perturbations within molecules under perturbed or turnover conditions. When utilized with other techniques, XAS can supply the metrical parameters required to understand the chemical properties of specific elements in a molecule.
X‐Ray Powder Diffraction
Authors: Clearfield Abraham , Bhuvanesh Nattamai
Published: March 2008

Crystalline solids may be described as containing a unit of matter that when repeated in three‐dimensional space reproduces the crystal. Because of the periodic nature of crystals and the fact that the distances between the atoms, that is, bond distances, are of the same order of magnitude as X‐ray wavelengths, the crystals act as diffraction gratings toward X‐ray beams. Diffraction from a small single crystal produces a three‐dimensional array of spots whose geometry can be related to the geometry of the unit cell and the three noncoplanar vectors that describe the periodic arrangement of the unit cells. Knowledge of the intensities of the diffracted radiation allows the determination of the atoms within the unit cell.

Many compounds occur as polycrystalline solids or powders. Most solids in nature are present as mixtures of two or more crystalline phases. Such materials still diffract X‐rays but the three‐dimensional array of spots is condensed into a one‐dimensional array of diffraction lines or near Gaussian peaks. Because of this low dimensionality much less data are obtained; however, a great deal of information may still be derived from the powder pattern referred to as X‐ray powder diffraction (XRPD) for XRPD pattern. In its simplest form the XRPD may be used as a fingerprint to identify a particular phase or mixture of phases. The amount of each phase may be determined quantitatively.

As the crystallite size decreases, the X‐ray peaks broaden, so it is possible to obtain a measure of the crystallite size. Lattice strain also contributes to peak broadening, requiring that the two effects be separated for accuracy in interpretation of the data. The advent of high speed computers and highly engineered diffractometers allows for rapid accurate analysis of powder mixtures or the study of solid solutions, defects and other complexities of crystalline material. It is, in many cases, possible to determine the crystal structure of compounds from their X‐ray powder data and this aspect of powder diffractometry is included here. Diffraction does not occur from amorphous solids, but X‐rays are scattered and much information on particle size and short range order can be obtained from small angle X‐ray and neutron scattering studies. Furthermore, EXAFS and Atomic Pair Distribution functions provide a means of probing the structures of amorphous and semicrystalline materials.
Circular Dichroism (
CD
) Spectroscopy
Authors: Presta P. Anthony , Stillman Martin J.
Published: March 2008

Circular dichroism (CD) spectroscopy is of fundamental importance as a tool in all areas of chemistry and biochemistry because this technique is the simplest and fastest measure of the presence of the chiral species that lead to optical activity. Chiral centers and chiral species exist from the simplest molecules to complex organic molecules, from inorganic complexes to metal‐based biological molecules, typically metalloproteins; from folded polymers, which are typically peptides and proteins; to the supramolecular organization of the quaternary structure of proteins; including all forms of helical structure typified by the the double helix; to liquid crystals and beyond, to even more massive and organized species. For all these species, CD spectroscopy provides insight into the presence and the extent of the chiral electric field induced by the atomic and molecular organization. The optical activity is detected under electronic and vibrational absorption bands as a result of the differential absorption of left‐ and right‐circularly polarized light. Measurement of mirror images of the CD spectrum is commonly used to determine the enantiomeric purity of small molecules. The measurement of the change, and sometimes loss, of optical activity measured in the spectral region of the chiral chromophores can be used to determine and understand the denaturation of a folded protein as the chirality changes with the change in gross structural features associated with the folding.

We focus particularly in this chapter on the influence of metals on the chiral properties of proteins. Metal binding results in changes in molecular and supramolecular conformations readily measured under metal‐based spectral bands. In cases for which the folding of the protein is almost entirely metal‐induced, the CD spectrum becomes an extremely sensitive marker for structural change as a function of metal loading allowing both the stoichiometry of metal binding and the coordination geometry to be proposed.

Measurement of the chirality of a molecule is easy in the region 190–1000 nm as several relatively inexpensive instruments provide high sensitivity. Time‐resolved CD spectral data are also readily achievable using stopped‐flow devices. Measurement in the infrared regions is also popular and provides invaluable information; instruments can now be purchased “off the shelf”. The new growth area is the use of synchrotron radiation as the light source allowing CD spectral data to be measured in all regions of the electromagnetic spectrum, but particularly, for energies higher than 50 000 cm
−1
(below 200 nm).
Electrochemistry
Authors: Elvington Mark C. , Brewer Karen J.
Published: March 2008

This chapter provides a summary of electrochemical methods with an emphasis on applications to inorganic chemistry. Electrochemical methods include potential sweep, potential step, and bulk methods including coupling of bulk electrolysis methods to characterization methods. Discussions include examples from the literature and important experimental considerations. Techniques discussed include cyclic voltammetry, differential pulse voltammetry and polarography, square wave voltammetry, and bulk electrolysis. The coupling of analysis methods including electronic absorption, IR and EPR spectroscopy to bulk electrolysis are provided. Discussions are tailored to the application of electrochemistry in inorganic chemistry research with practical considerations and illustrative examples provided.
Magnetism and Phase Formation in the Candidate Dilute Magnetic Semiconductor System In2 − xCrxO3: Bulk Materials are Dilute Paramagnets
Authors: Bizo L. , Allix M. , Niu H. , Rosseinsky M. J.
Published: March 2008

Well‐characterized bulk materials in the candidate dilute magnetic semiconductor system In2 − xCrxO3 are prepared for 0 ≤ x < 0.15, with cation site preferences in the bixbyite structure identified by diffraction methods. Small ferromagnetic moments are observed; their size (<10−2 µB/dopant ion) is not consistent with bulk ferromagnetism. The resulting bulk materials display dilute paramagnetic behaviour, with all of the moment expected per Cr3+ cation dopant being involved in this paramagnetic response.
Template Synthesis of Aligned Carbon Nanotube Arrays using Glucose as a Carbon Source: Pt Decoration of Inner and Outer Nanotube Surfaces for Fuel‐Cell Catalysts
Authors: Wen Zhenhai , Wang Qiang , Li Jinghong
Published: March 2008

A facile method is developed to synthesize aligned arrays of open‐ended carbon nanotubes (CNTs) via in situ glucose polymerization in the inner pores of anodic aluminum oxide templates under hydrothermal conditions, followed by carbonization at high temperature. Pt nanoparticles are decorated on the surfaces of the as‐prepared CNTs using the incipient wet method based on the use of NaBH4 as a reductant. Characterization of the resulting structures by transmission electron microscopy and field‐emission scanning electron microscopy demonstrates that the Pt nanoparticles are anchored on both the inner and outer walls of CNTs, thus giving rise to a shell–core–shell‐like nanotube composite. The electrocatalytic properties of the Pt–CNT–Pt electrodes are investigated for methanol oxidation by cyclic voltammetry and chronoamperometric measurements. It is found that the hybrid electrodes show superior catalytic performance compared to commercial carbon‐black‐supported Pt. The increased catalytic efficiency of Pt might be a result of the unique morphology of these structures.
Two‐Dimensional Hexagonally‐Ordered Mesoporous Carbon Nitrides with Tunable Pore Diameter, Surface Area and Nitrogen Content
Authors: Vinu Ajayan
Published: March 2008

Two‐dimensional mesoporous carbon nitride (MCN) with tunable pore diameters have been successfully prepared for the first time using SBA‐15 materials with different pore diameters as templates through a simple polymerization reaction between ethylenediamine (EDA) and carbon tetrachloride (CTC) by a nano hard‐templating approach. The obtained materials have been unambiguously characterized using X‐ray diffraction (XRD), N2 adsorption, high‐resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), high‐resolution scanning electron microscopy (HRSEM), X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT‐IR) spectroscopy, and CHN analysis. The results show that the pore diameter of the MCN materials can be easily tuned from 4.2 to 6.4 nm without affecting their structural order. XRD, HRTEM and N2 adsorption results reveal that the materials are structurally well ordered with a two‐dimensional porous structure, a high surface area and a large pore volume. It is also demonstrated for the first time that the textural parameters such as the specific pore volume, the specific surface area and the pore diameter, and the nitrogen content of the MCN materials can be controlled by the simple adjustment of the EDA to CTC weight ratio. The carbon to nitrogen ratio of the MCN decreases from 4.3 to 3.3 with increasing EDA to CTC weight ratio from 0.3 to 0.9. The optimum EDA to CTC weight ratio required for fabricating the well‐ordered MCN materials with excellent textural parameters and high nitrogen content is around 0.45. The catalytic activity of the materials has been tested in the Friedel‐Crafts acylation of benzene using hexanoyl chloride as the acylating agent. The materials are highly active and show a high conversion and 100 % product selectivity to caprophenone.
Optimization of a pulsed operation of gas separation by membrane
Authors: Corriou Jean‐Pierre , Fonteix Christian , Favre Eric
Published: March 2008

A pulsed cyclic membrane process, originally proposed by Paul for gas separations, has been investigated through a simulation and optimization study. For carbon dioxide hydrogen separation, it is shown that cyclic operation, based on an already reported material, could potentially compete with the most selective, still virtual, polymers, both in terms of selectivity and productivity. The use of asynchronous cycling operation, unexplored up to now, has been more specifically investigated. This mode of operation offers an extended range of performances from the point of view of the selectivity‐productivity trade‐off. A dedicated optimization study based on either nonlinear or genetic algorithm approach shows that, for this system, synchronous operation offers the best performances. These results have been confirmed by multiobjective optimization by means of the genetic algorithm. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Principles for hearing grievances, and an effective response
Authors: Rees Caroline
Published: March 2008

Two CPR Fall 2007 Meeting panelists re‐team to expand their focus on corporate social responsibility and its relationship to conflict resolution. First, John Sherman, of Westborough, Mass., describes why his employer, energy provider National Grid, focuses substantial business efforts on giving communities a voice in its efforts. Caroline Rees, of Cambridge, Mass., examines the need for grievance mechanisms to address inevitable local conflicts. Both authors provide practical advice based on adaptable existing models.
Graft copolymerization of acrylamide onto tamarind kernel powder in the presence of ceric ion
Authors: Goyal Puja , Kumar Vineet , Sharma Pradeep
Published: March 2008

Tamarind kernel powder (TKP), a natural xyloglucan polysaccharide is derived from the seeds of Tamarindus indica Linn., a common and most important tree of India and South East Asia. TKP is used in cotton sizing, as a wet‐end additive in the paper industry, as a thickening, stabilizing, and gelling agent in the food industry. Chemical modification of TKP through grafting has received considerable attention to impart new functional groups for different applications. Keeping this in view, graft copolymerization of acrylamide (AA) onto TKP was carried out in an aqueous medium using a ceric ammonium nitrate (CAN)‐nitric acid initiation system. The reaction conditions were optimized for grafting with respect to the effect of the concentrations of CAN, nitric acid, TKP, AA, time, and reaction temperature. The maximum percentage grafting (%G) and percentage grafting efficiency (%GE) were found to be 231.45 and 93.66%, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Hydrogel–hydrogel composites: The interfacial structure and interaction between water and polymer chains
Authors: Li Xinming , Cui Yingde , Xiao Jianliang , Liao Liewen
Published: March 2008

This work examines the interfacial structure and interaction between water and polymer chains in the hydrogel–hydrogel composites with the goal of establishing foundations for further investigation of drug diffusion from one hydrogel to another in the soft contact lens. This is based on the ability of the hydrogel–hydrogel composites to release ophthalmic drugs in a sustained manner. The hydrogel–hydrogel composites were synthesized by immersing the glycerol‐swollen particles of crosslinked N‐vinyl‐2‐pyrrolidone (NVP) into the monomer of hydroxyethylmethacrylate (HEMA) containing initiator benzoylperoxide (BPO) that polymerizes to form a matrix in the presence of the first networks. The hydrogel–hydrogel composites were characterized by UV/Vis spectrophotometer, scanning electronic micrography (SEM), and differential scanning calorimetry (DSC). The results showed that the samples of hydrogel–hydrogel composites of the particles of crosslinked NVP and poly‐HEMA were transparent and glassy and suitable for soft contact lens. Three types of the interfacial structure, no interpenetrating interface, partly interpenetrating interface, and fully interpenetrating interface, of the hydrogel–hydrogel composites existed, and the type of the interfacial structure was determined by the degree to which the monomer of HEMA penetrated into the first networks before formation of the matrix. Different from poly‐HEMA hydrogels, the peaks near 0°C on DSC curves of the hydrogel–hydrogel composites did not split while they were kept acute, and the amount of freezable‐bound water was less. This shows that the water incorporated in the hydrogel–hydrogel composites does not strongly interact with polymer matrix, so the hydrogel–hydrogel composites cannot keep their shape during the phase transition of water. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Mathematik, Naturwissenschaften und Technik als Bestandteile der Kultur der Gegenwart
Authors: Tobies Renate
Published: March 2008

Mathematics, Natural Sciences and Technology – Parts of the Encyclopedia Die Kultur der Gegenwart (The culture of today). The paper explores the trend of the early 20th century to consolidate mathematics, natural sciences, medicine and technology under the umbrella of one integrative culture – a tendency which contrasts with the increasing mainstream trend of separating the humanities from the natural sciences. The unifying umbrella was framed by the great encyclopedia Die Kultur der Gegenwart which was published by B. G. Teubner from 1905 to 1925 and was planned to run up to 62 volumes. We analyze the quantitative rate of the parts devoted to the humanities, the natural sciences and technology, respectively, the degree to which these parts were completed in this encyclopedia. In particular, we investigate the role of mathematicians and their reasons to find a classification for the mathematical, natural scientific and engineering parts of culture as well as their reasons, to win Nobel prize winners and other famous scientists to become co‐editors and authors. We examine the published volumes in the fields of mathematics, chemistry, physics, astronomy and technology in order to show what type of publication – professional or popular – was intended. Furthermore, we illuminate how the educational reform of mathematics, natural sciences and technology of this period – which included a reform of girls' and women's education – was reflected in the encyclopedia Die Kultur der Gegenwart.
Wissenschaftssystematik als Kulturaufgabe. Möglichkeiten eines offenen Kulturbegriffs in Paul Hinnebergs Enzyklopädieprojekt
Authors: Ziche Paul
Published: March 2008

The systematization of the sciences as a cultural task. Options for an open understanding of culture in Paul Hinneberg's Encyclopedia. – Paul Hinneberg promises, in his multi‐volume Kultur der Gegenwart (1906sqq.), to capture the ‘culture’ of his time in its entirety; only a veritable encyclopedia could be adequate to the task of synthesizing the manifold and disparate tendencies of ‘Kultur’. Surprisingly, however, any attempt to make explicit the systematic principles governing his encyclopedic synthesis is missing from his project. It is argued that this – unusual – feature of Hinneberg's Kultur der Gegenwart can itself be understood as a result of typical analyses of ‘Kultur’ at the turn of the century; culture, as an open, multi‐sided, and integrative concept may indeed best be captured in an open system that avoids strict and explicit demarcations. In these respects, the task of capturing Kultur turns out to be closely linked to another task prominent around 1900: that of providing a systematic ordering of the various ‘Wissenschaften’.
A New Photothermal Therapeutic Agent: Core‐Free Nanostructured AuxAg1−x Dendrites
Authors: Hu Kuo‐Wei , Huang Chih‐Chia , Hwu Jih‐Ru , Su Wu‐Chou , Shieh Dar‐Bin , Yeh Chen‐Sheng
Published: March 2008

A new class of AuxAg1−x nanostructures with dendrite morphology and a hollow interior were synthesized by using a replacement reaction between Ag dendrites and an aqueous solution of HAuCl4. The Ag nanostructured dendrites were generated by the reaction of AgNO3 with ascorbic acid in a methanol/water system. The dendrites resemble a coral shape and are built up of many stems with an asymmetric arrangement. Each stem is approximately 400 nm in length and 65 nm in diameter. The bimetallic composition of AuxAg1−x can be tuned by the addition of different amounts of HAuCl4 to the Ag dendritic solution. The hollowing process resulted in tubular structures with a wall thickness of 10.5 nm in Au0.3Ag0.7 dendrites. The UV/Vis spectra indicate that the strongest NIR absorption among the resulting hollow AuxAg1−x dendrites was in Au0.3Ag0.7. The MTT assay was conducted to evaluate the cytotoxicity of Ag dendrites, hollow Au0.06Ag0.94 and Au0.3Ag0.7 dendrites, and Au nanorods. It was found that hollow Au0.06Ag0.94 and Au0.3Ag0.7 dendrites exhibited good biocompatibility, while both Ag dendrites and Au nanorods showed dose‐dependent toxicity. Because of absorption in the NIR region, hollow Au0.3Ag0.7 dendrites were used as photothermal absorbers for destroying A549 lung cancer cells. Their photothermal performance was compared to that of Au nanorod photothermal therapeutic agents. As a result, the particle concentration and laser power required for efficient cancer cell damage were significantly reduced for hollow Au0.3Ag0.7 dendrites relative to those used for Au nanorods. The hollow Au0.3Ag0.7 nanostructured dendrites show potential in photothermolysis for killing cancer cells.
Calculation of conformational energies and optical rotation of the most simple chiral alkane
Authors: Grimme Stefan , Mück‐Lichtenfeld Christian
Published: March 2008

Quantum chemical calculations have been performed to investigate the conformer distribution of 4‐ethyl‐4‐methyloctane and its optical rotation. With the reference methods MP2 and SCS‐MP2, the energies of seven conformers are found within a range of about 1.5 kcal mol−1. It is demonstrated that the relative energies cannot be reliably predicted with conventional GGA or hybrid density functionals, Hartree‐Fock, semiempirical AM1, and classical force field (MM3) calculations. An empirical dispersion correction to GGA (PBE‐D), hybrid (B3LYP‐D), or double hybrid (B2PLYP‐D) functionals corrects these errors and results in very good agreement with the reference energies. Optical rotations have been calculated for all seven conformers at the TDDFT(BHLYP/aTZV2P) level. The computed macroscopic rotation is derived from a classical Boltzmann average. The result (1.9–3.2 deg dm−1 (g/mL)−1) is very close to the experimental value of 0.2 deg dm−1 (g/mL)−1 for the (R)‐enantiomer and has the right sign. Because six conformers are significantly populated at room temperature and the rotations of individual conformers differ in sign and magnitude, the calculated average rotation is rather sensitive to the conformer population used. From the electronic structure point of view, this example emphasizes the effect of long‐range dispersion effects for the evaluation of population averaged quantities in large molecules. Computations based on free enthalpies are in worse agreement with experiment that is attributed to artefacts of the harmonic approximation used to compute the vibrational entropy terms. Chirality, 2008. © 2008 Wiley‐Liss, Inc.
Diversity in mammalian chiasmatic architecture: Ipsilateral axons are deflected at glial arches in the prechiasmatic optic nerve of the eutherian Tupaia belangeri
Authors: Knabe Wolfgang , Washausen Stefan , Happel Nicole , Kuhn Hans‐Jürg
Published: March 2008

Permanent ipsilaterally projecting axons approach the chiasmatic midline in rodents but are confined to lateral parts of the optic chiasm in marsupials. Hence, principally different mechanisms were thought to underlie axon pathway choice in eutherian (placental) and marsupial mammals. First evidence of diversity in eutherian chiasmatic architecture came from studies in the newborn and adult tree shrew Tupaia belangeri (Jeffery et al. [1998] J. Comp. Neurol. 390:183–193). Here, as in marsupials, ipsilaterally projecting axons do not approach the midline. The present study aims to clarify how the developing tree shrew chiasm is organized, how glial cells are arranged therein, and the extent to which the tree shrew chiasm is similar to that of marsupials or other eutherians. By using routinely stained serial sections as well as immunohistochemistry with antibodies against glial fibrillary acidic protein, vimentin, and medium‐molecular‐weight neurofilament protein, we investigated chiasm formation from embryonic day 18 (E18) to birth (E43). From E22 onward, ipsilaterally projecting axons diverged from contralaterally projecting axons in prechiasmatic parts of the optic nerve. They made sharp turns when arriving at glial arches found at the transition from the optic nerve to the chiasm. Thus, during the ingrowth period of axons, Tupaia belangeri and marsupials have specialized glial arrays in common, which probably help to deflect ipsilaterally projecting axons to lateral parts of the chiasm. Our observations provide new evidence of diversity in eutherian chiasmatic architecture and identify Tupaia belangeri as an appropriate animal model for studies on the mechanisms underlying axon guidance in the developing chiasm of higher primates. J. Comp. Neurol. 508:437–457, 2008. © 2008 Wiley‐Liss, Inc.
Adenolipoma of the thyroid gland: Report of a case with diagnosis by fine‐needle aspiration cytology
Authors: Kim Hun‐Soo , Yun Ki‐Jung
Published: March 2008

Adenolipomas are rare benign neoplasms composed of mature adipose tissue and thyroid follicles. The preoperative fine‐needle aspiration cytology of such lesion has rarely been cited. Approximately 12 cases have been reported in the literature worldwide, diagnosed solely on histopathology. A 65‐year‐old woman presented with a 4‐month history of a thyroid nodule. A FNA cytology specimen showed a few benign follicular cells with adipose tissue. Right lobectomy was performed and the specimen revealed a solid yellowish mass measuring 3 × 2.5 cm. Microscopic findings showed a solid tumor predominantly composed of mature adipose tissue intermixed with thyroid follicles. The pathological diagnosis was adenolipoma of the thyroid gland. The presence of adipose tissue is a common finding within the cytologic specimen, especially in obese individuals or with inadequate sampling. But suspicion may be possible if excess amounts of adipose tissue are present in the submitted sample. Diagn. Cytopathol. 2008;36:253–256. © 2008 Wiley‐Liss, Inc.