bluuebunny/crossref_metadata_2025 huggingface dataset:
Silicon Nitride Ceramics
Authors: Hampshire Stuart
Published: March 2009

Silicon nitride is one of the major structural ceramics that has been developed following many years of intensive research. It possesses high flexural strength, high fracture resistance, good creep resistance, high hardness and excellent wear resistance. These properties arise from the processing of the ceramic by liquid phase sintering and the development of microstructures in which high aspect ratio grains and intergranular glass phase lead to excellent fracture toughness and high strength. The glass phase softens at high temperature and controls the creep rate of the ceramic. The purpose of this review is to examine the development of silicon nitride and the related sialons and their processing into a range of high-grade structural ceramic materials. The development of knowledge of microstructure–property relationships in silicon nitride materials is outlined, particularly recent advances in understanding the effects of grain boundary chemistry and structure on mechanical properties. This review should be of interest to scientists and engineers concerned with the processing and use of ceramics for structural engineering applications.
Study of Compensation Defects and Electron Irradiation-Induced Defects in Undoped SI-InP by Positron Lifetime Spectroscopy
Authors: Zhang Y.J. , Deng Ai Hong , Zhao You Wen , Yu J. , Yu X.X. , Cheng X. , Zhou Y.L. , Long J.J.
Published: March 2009

Positron annihilation lifetime (PAL) spectroscopy，photo-induced current transient spectroscopy (PICTS) and thermally stimulated current (TSC) have been employed to study the formation of compensation defects and their evolvement under iron phosphide (IP) ambience or pure phosphide (PP) ambience. In the formation of IP SI-InP, the diffusion of Fe atoms suppresses the formation of some open-volume defects. As to PP SI-InP, VInH4 complexes dissociate into acceptor vacancies VInHn(n-3)(n=0,1,2,3), which compensate residual donor type defects and make the sample semi-insulating. Electron irradiation-induced deep level defects have been studied by TSC in PP and IP SI-InP, respectively. In contrast to a high concentration of irradiation-induced defects in as-grown and PP annealed InP, IP SI-InP has a very low concentration of defects.
Characterizing Native Point Defects in ZnO Bulk by Positron Annihilation Spectroscopy
Authors: Peng C.X. , Weng Hui Min , Wang K.F. , Guo F.L. , Ye B.J. , Zhou X.Y. , Han Rong Dian
Published: March 2009

Positron annihilation spectroscopy was employed to study the native point defects in ZnO single crystal, in combination with calculated results of positron lifetime and electron momentum distribution. The theoretical and experimental results of the positron lifetime in ZnO bulk ensure the presence of zinc monovacancy, and zinc monovacancy concentration begins to decrease above 600oC annealing treatment. Oxygen vacancies have been characterized by coincidence Doppler broadening (CDB) spectroscopy, combined with calculated electron momentum distribution. CDB spectroscopies show that oxygen vacancies don't appear until 600oC annealing treatment, and increase due to ZnO decomposition with annealing temperature rising.
Hydrogen Bonded Supra Molecular Structure as Studied by Positron Annihilation Spectroscopy
Authors: Ganguly Bichitra Nandi
Published: March 2009

Hydrogen bonded supra molecular structure is the essential feature of cinnamic acid (phenyl acrylic acid) while forming a layered crystal structure in solid state. It is an aromatic compound with strong hydrogen bonding between the carboxylic groups. The dimers are interconnected by CH….O intermolecular hydrogen bonds, with C-H unit mostly originating from aromatic ring. These bonds keep the dimers and higher oligomers together and thus the compound exists in crystalline form. Since the hydrogen bonded structure is susceptible to rupture at temperature changes above the ambient, a temperature dependent positron annihilation spectroscopic study has been performed to investigate the changes of its molecular structure. These subtle changes were investigated independently through differential scanning calorimetry (DSC), which sheds light on the activation energy of the molecular state at different temperature regimes and indicates the phase transition temperature.
Free Volume Seen by Positronium in Bulk and Confined Molecular Liquid
Authors: Iskrová Martina , Majerník V. , Illeková Emília , Šauša O. , Berek D. , Krištiak Jozef
Published: March 2009

Results of positron annihilation experiments on bulk hexadecane and hexadecane filled into silica gel nano pores will be reported. The lifetime and Doppler broadening measurements were performed at the temperature range (14-300) K. The annihilation data were combined with output of the differential scanning calorimetry at range from 270K up to 300K.
Dipositronium and other Two-Positronium Compounds
Authors: Schrader David M.
Published: March 2009

Dipositronium, Ps2, was recently prepared [1]. This is significant because: • It is the first laboratory observation of a molecule that contains more than one positron; • It is the most symmetrical molecule possible; • It is the most non-rigid (floppiest) molecule possible; • The interval between the theoretical establishment of its existence [2] and its laboratory observation [1] is inordinately long – 60 years; and • An extension of the technology developed for the Ps2 observation may soon lead to an observation of the Bose-Einstein condensation of positronium and the development of a gamma ray laser. We briefly discuss the symmetry of Ps2 and how an understanding of it will underlie its characterization in the future. Ps2O and CPs2 might be the next two-positron compounds to be prepared and characterized in the laboratory. A discussion of the contrasting eigenstates of these two molecules is given. An understanding of these states is required in order to identify them.
A Novel Approach to the Interpretation of PAL Spectra in Glycerol
Authors: Stepanov Sergey V. , Zvezhinskiy Dmitry , Duplâtre Gilles , Byakov Vsevolod , Subrahmanyam V.S.
Published: March 2009

A new strategy for the treatment of positron annihilation lifetime (PAL) spectra in viscous liquids is proposed, enabling to extract values of the Ps reaction rate constants with intratrack radiolytic products as well as parameters of the free volume distribution in viscous media.
Application of Positron Microprobe for Nuclear Materials
Authors: Maekawa Masaki , Kawasuso Atsuo , Hirade Tetsuya , Miwa Y.
Published: March 2009

We have developed a positron microbeam using magnetic lenses based on the commercial scanning electron microscope. The minimum beam diameter was 1.9 μm on target. Two-dimensional image of S parameter was successfully obtained. Using this apparatus, S parameter distribution around the crack tip introduced by a stress corrosion cracking of a stainless steel was obtained. S parameter increases at the further region of the tip of the crack. This shows that vacancy type defects may be generated as crack precursor.
S-Wave Resonances in Positron Scattering from Li and Na
Authors: Han Hui Li , Shi Ting Yun
Published: March 2009

We have calculated S-wave resonances in the e+-Li and e+-Na systems using the stabilization method in the framework of hyperspherical coordinates. We have located all the previously known S-wave resonances predicted by Ho [1,2] and observed relatively good agreement for the resonance positions. In addition, the resonances associated with the Ps (n=2) threshold for the e+-Na and e+-Li systems are reported for the first time.
Positron Annihilation Lifetime Study of Graft-Type Fluorinated Polymer Electrolyte Membranes
Authors: Sawada Shin-ichi , Kawasuso Atsuo , Maekawa Masaki , Suzuki Akihiro , Terai Takayuki , Maekawa Yasunari
Published: March 2009

Positron annihilation lifetime spectroscopy (PALS) measurements were performed on polymer electrolyte membranes (PEMs) synthesized by radiation-induced graft polymerization of styrene into crosslinked-polytetrafluoroethylene (cPTFE) films and subsequent sulfonation. The base cPTFE and polystyrene grafted films were also measured as references. The cPTFE based PEM was found to have free-volume holes with different radius of 0.28-0.30 nm and 0.44-0.45 nm. The larger holes may be located in PTFE amorphous regions, while the smaller ones are considered to exist in both PTFE crystallites and poly(styrene sulfonic acid) grafts containing no water.
Properties of ZnO Thin Films Grown on Si Substrates by Ultrasonic Spray and ZnO/Si Heterojunctions
Authors: Zebbar N. , Aida M.S. , Hafdallah A.E.K. , Daranfad O. , Lekiket H. , Kechouane M.
Published: March 2009

Experimental analysis of current –voltage and capacitance-voltage characteristics of n-ZnO/p-Si (100) heterostructures were presented. Undoped and In-doped ZnO films were deposited by the simple ultrasonic spray method on p-Si substrates (100) at varied substrate temperatures from 200 to 400°C.
The structural and optical properties of ZnO films were investigated using X-ray diffraction (XRD) and transmission spectra respectively. The electrical conductivity is calculated from transport measurement in a two probes coplanar structure. It is found that the doped ZnO: In films have higher (002) diffraction peak than undoped ZnO. All films exhibit a high transparency about 85%. The maximum conductivity is observed at 350°C for doped films but increases with substrate temperature for undoped ones.
Current–voltage (I-V) characteristics of all n-ZnO/p-Si heterojunctions exhibit non linear characteristics with a small current leakage in the reverse voltage. The obtained device shows a barrier height in the order of 0.65 eV, this is consistent with the theoretical value 0.67eV.
The capacitance increases with increasing reverse bias in an approximately linear 1/C2-V relationship.
Adsorption of Dyes and Metal Ions by Acrylamide - Co - Acrylic Acid Hydrogels Synthesized by Gamma Radiation
Authors: Aberkane-Mechebbek L. , Larbi-Youcef S.F. , Mahlous M.
Published: March 2009

Hydrogel based on acrylamide and acrylic acid was synthesized and crosslinked by gamma radiation at an absorbed dose of 8 kGy. Swelling properties of the hydrogel in water and in methyl violet and Congo red solutions were investigated. The results showed that the swelling rate of the hydrogel depends on the pH and the ionic nature of the dye. Diffusion of water and dyes solutions within the hydrogel was found to be of non-Fickian character. Contrary to the swelling behavior, the capacity of the hydrogel to adsorb dyes seems to be higher at weak pHs. Concerning metal ions uptake, the results showed that adsorption of Cu2+ increases with pH increasing from pH1 to pH4.
Characterization of CNx Thin Films Synthesized by Laser Ablation Technique
Authors: Zouadi N. , Abdelli-Messaci Samira , Gabouze N. , Kerdja Tahar , Bradai D.
Published: March 2009

In this work we report the optical characteristics of carbon nitride films produced by a KrF excimer laser ablation technique. The ablated materials were collected on different wafers, glass and porous silicon for different N2 pressures (0.1-0.5mbar). The thin films were synthesized at room temperature. The deposited thin films were characterized by spectrophotometry, ellipsometry, scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The results show that the optical band gap deduced from optical transmission spectra in the ultraviolet- visible – near infrared range increases with deposition time and with nitrogen pressures increasing. SEM observation indicates that the CNx film is granular. Finally, FTIR spectra reveal carbon nitride absorption bands which do not seem change considerably with N2 pressures.
Synthesis and Characterization of Porous Materials Containing Modified Cellulose by β-Cyclodextrin for the Application in Processing Industrial Liquid Waste
Authors: Ghemati Djamila , Aliouche Djamel
Published: March 2009

The cellulose made up the principal structure of many plants. The content varies according to the vegetable species, from approximately 40% in wood, to 95-99% in cotton fibers. Several ways are possible to bring an additional function to cellulose: new fibers, modification of the fibrous structure, physical or chemical treatment by a surface treatment. And due to the contribution of functions, the formerly passive cellulose becomes active. Capacity of cyclodextrins to facilitate the inclusion of hydrophobic molecules, and others chemical derivatives like the dyes, can be exploited to obtain new porous materials modify with particular performances. In this work, a porous cellulosic material modifies was obtained by chemical modification and fixing of β-cyclodextrin on polymeric surface. The results were confirmed by infra-red analysis (FTIR) and scanning electron microscopy (SEM). The experiments of adsorption of balance of a reactive dye were made in aqueous solutions for 48 hours. Our results indicate the formation of a permanent chemical bond between the β - cyclodextrin and the fibrous material, and the modification is done without change of the polymer structure, the inclusion of the molecules of dyes in the cavity of cyclodextrin is due to the several interactions. The results of dye adsorption in aqueous medium show the aptitude of porous materials to fix the dangerous industrial dyes, and used in the processing industrial liquid waste.
Synthesis and Characterization of New Chelating Resin Functionalized with Pyrocatechol Violet and its Application as Extractant for Zinc (II)
Authors: Belaid T. , Aitali S. , Benamor M. , Belhamel K.
Published: March 2009

A new chelating resin, pyrocatechol violet (PV) immobilised on Amberlite XAD-4 polymeric matrix, was prepared. The resulting chelating resin has been characterised by elemental analysis, infrared (IR) spectra and textural analysis (BET). The resin was used for the preconcentration of Zn (II) prior to its determination by flame atomic absorption spectrometry (AAS). The optimization of experimental conditions during the quantitative extraction of Zn (II) by the resin phase was performed using factorial design including pH, amount of resin, and contact time.
The phase exchange kinetic studies performed of Zn (II) revealed that equal 40 min was sufficient for reaching equilibrium metal ion sorption. Sorption is quantitative in the pH range of 5 – 5.5 (recovery 98 – 99%).
Evaluation of Atmospheric Corrosivity by ACM Technique
Authors: Cao Xian Long , Xiao Yi De , Deng Hong Da , Cao Peng Jun , Jia Bi
Published: March 2009

The atmospheric corrosion has been shown to be an electrochemical process, the atmospheric corrosion behavior of Q235 stell evaluated with ACM (Atmospheric corrosion monitor) electrochemical technique was investigated in the study. The experimental results showed that there existed a close relation between electrochemical data and climatic parameters was confirmed. Taking into consideration accuracy and sensitivity of electrochemical technique, the ISO-standardized time of wetness (TOW) seems to be too conservative. SO2 seems to be more aggressive than chloride on metal corrosion in the early stage of atmospheric corrosion but the complexion reverses in the final stage of atmospheric corrosion. The ratio of corrosion rate from integration of ACM current to corrosion rate from weight loss of test specimens, that is, cell factor is fairly constant at the same test site but varied greatly between test sites. Based on constant cell factors and close relation between electrochemical data and climatic parameters in all test sites, ACM electrochemical technique can evaluate and classify the short-term atmospheric corrosivity as a substitute for gravimetric method, and the verification shows that atmospheric corrosivity classifications according to integration of ACM current and especially to cell factor coincide with the specifications of ISO Standard.
Preparation of PPy/CNT Composite Applications for Supercapacitor Electrode Material
Authors: Du B. , Jiang Qi , Zhao X.F. , Huang B. , Zhao Y.
Published: March 2009

In this paper, the CNT was used as the reinforcing material to overcome the PPy swelling and shrinkage during the doping-undoping process. The electrochemical capacitance is about 25 F/g in organic electrolyte. The PPy/CNT composite (2:1, m/m) was prepared by depositing the polypyrrole onto functionalized multi-walled CNT in aqueous-methanol solution via chemical polymerization. The obtained composite material was characterized by scanning electron microscopy and infrared spectrum. And the electrochemical performance of the composite material was tested by cyclic voltammetry and galvanostatic charging–discharging cycling. The results showed that the obtained polymer was the PPy and sheet; moreover, the PPy was coated on surface of the CNT. The electrochemical capacitance was about 154.5 F/g (organic electrolyte), which was about 6 times that of pure PPy (about 25 F/g).
Experimental Study of the Mechanical Properties of Hybrid Fiber Reinforced Concrete
Authors: Hua Yuan , Zhou Tai Quan
Published: March 2009

Different kinds of fiber are used to reinforce the concrete to improve the concrete mechanical properties. The high modulus and high flexibility fibers are often used to reinforce in the cement base, which leads to the higher performance compound cement based materials. In the paper, the carbon fiber and glass fiber material are used as flexibility reinforced materials. The polypropylene fiber and the polyethylene fiber are used as strength reinforced materials. The combinations of the flexibility reinforced fiber and strength reinforced fiber are chosen as C-P HF (Carbon and Polypropylene Hybrid Fiber) and G-Pe HF (Glass and Polyethylene Hybrid Fiber). The concrete mixture ratio and the fiber-reinforced amount are determined to the author’s previous study. The relationship between compressive strength, flexural strength and length/diameter aspect ratio of fiber for the carbon and polypropylene hybrid fiber reinforced concrete (C-P HFRC), and for the glass and polyethylene hybrid fiber reinforced concrete (G--Pe HFRC) was tested and discussed. The testing results show that length/diameter aspect ratio of fiber obviously affects the flexural strength of C-P HFRC and G-Pe HFRC, though the compressive strength is slightly affected by the length-diameter aspect ratio.
A Study on Corrosion Inhibitor for Magnesium Alloy
Authors: Yang Xu , Pan Fu Sheng , Zhang Ding Fei
Published: March 2009

With the aim of evaluating corrosion inhibition for various inhibitors, a new qualitative method for corrosion inhibition effect test for magnesium and magnesium alloys was developed. The change of polarization current density of AZ61 magnesium alloy in electrochemical polarization experiments in alkali aqueous solution with 5mmol/L sodium dodecylsulphate(SDS), phytic acid(PA), ethylenediamine tetraacetic acid(EDTA), p-nitro-benzene-azo-resorcinol(PNBAR), acidum tannicum(AT) or stearic acid(SA) were tested. The SEM-EDS techniques and deposition experiment method were used for further confirmation of the corrosion inhibition. The results showed that those organic compounds which could form the inhibitor-magnesium precipitation in aqueous solution could be used as corrosion inhibitors for magnesium alloys to inhibit the increase of polarization current density as well as the dissolution and oxidation of magnesium alloys effectively.
Study on the Fatigue Property for Aged Asphalt Mixtures by Using Four Point Bending Tests
Authors: Zhu Guo Jun , Wu Shao Peng , Liu Ran , Zhou Lei
Published: March 2009

The effects of aging on the fatigue property of polymer modified asphalt mixtures are investigated in this paper. Two kinds of aging procedures are adopted for the aging of specimens prepared with polymer modified asphalt mixtures. One is the short-time aging which means that the hot asphalt mixtures was heated in the oven for 4 hours at 135°C before compacted; The other called natural aging, with the original specimen exposed in the sunlight and subjected to the rain and temperature change for 3, 6 and 9 months. Four-Point Bending Test was conducted to evaluate fatigue properties of aged asphalt mixtures at 15°C compared with the original specimens. Test results indicate that the fatigue line of aged specimens have the same tendency as the original asphalt mixtures. However, the life of aged specimen is decreased significantly when compared with the original ones, especially of the natural aged specimens.
Poroelasticity of Fluid-Saturated Nanoporous Media
Authors: Pensée Vincent , He Qi Chang , Le Quang H.
Published: March 2009

The purpose of this work is to extend the equations of linear poroelasticity to the case of materials with nanopores. We consider a model of microstructure which corresponds to an assemblage of hollow spheres saturated by a fluid. The solid phase is linearly elastic and isotropic; pores are assumed to be of nanometric size. To account for the pore surface stresses, the Young-Laplace model is used. The nanopore size effects on the effective bulk modulus, Biot’ modulus and coefficient are shown. When pores are sufficiently large, the classical relations of linear poroelasticity are retrieved.
Climbing behaviour and aphid predation byAgonum muelleri(Coleoptera: Carabidae)
Authors: Hannam Joshua J. , Liebherr James K. , Hajek Ann E.
Published: March 2009

Field-collectedAgonum muelleri(Herbst) adults were videotaped to assess their ability to climb soybean (Glycine max(L.) Merr. (Fabaceae)) plants. All individuals climbed up and down soybean plants multiple times.Agonum muellerispent from 12.5 ± 3.4% to 54.1 ± 11.3% of their time on soybean plants. CagedA. muelleriadults on plants infested with soybean aphids,Aphis glycines Matsumura (Hemiptera: Aphididae), reduced the number of apterous adults. The presence of predators had an indirect effect on the density of nymphal aphids by reducing the numbers of adult aphids.Agonum muelleri, an abundant carabid in soybean fields, readily climbs soybean plants to feed on soybean aphids.
Expert testimony in child sexual abuse cases: The effects of evidence, coherence and credentials on juror decision making
Authors: Klettke Bianca , Graesser Arthur C. , Powell Martine B.
Published: March 2009

Psychological experts have been used increasingly to testify in child sexual abuse cases, yet little research has investigated what specific factors make experts effective. This study examined the potential effects that credentials, evidence strength and coherence may have on juror decision making. Sixty‐four mock jurors read cases of child sexual abuse, followed by experts' testimony and rated guilt of the defendant, effectiveness of the expert testimony and credibility of the victim. Evidence strength and coherence of the testimony affected all dependent variables, and the interaction was significant. Guilt ratings of the defendant were lower and the victim was rated as less credible when both evidence strength and coherence were low. The credentials of the expert, however, had negligible impact. These findings indicate that experts can be effective and impact jurors when testimony is either high in coherence or high in evidence. Copyright © 2009 John Wiley & Sons, Ltd.
Unusual Lattice‐Magnetism Connections in MnBi Nanorods
Authors: Kang Kyongha , Yoon Won‐Sub , Park Sangmoon , Moodenbaugh Arnold R. , Lewis Laura H.
Published: March 2009

Lattice parameter, particle size, and thermal expansion results obtained from high‐temperature synchrotron transmission X‐ray diffraction are reported for magnetostructual NiAs‐type MnBi nanorods embedded in a Bi matrix. The structural data are consistent with elevated‐temperature magnetic measurements that indicate a first‐order nanorod Curie transition at 520 K, significantly depressed from the bulk MnBi Curie temperature of 633 K. The data suggest that the unit cell volume dependence of the magnetic behavior—also known as the volume exchange striction—of the MnBi compound is the determining factor underlying this phenomenon. The results imply that materials with magnetostructural transitions of technological interest may be altered by strain effects to tailor the interatomic distances towards the critical transition values.
Engineering LacI for Self‐Assembly of Inorganic Nanoparticles on DNA Scaffold through the Understanding of LacI Binding to Solid Surfaces
Authors: Chen Haibin , Su Xiaodi , Neoh Koon‐Gee , Choe Woo‐Seok
Published: March 2009

The potential of utilizing the DNA binding protein lac repressor (LacI) to organize inorganic nanoparticles (NPs) is explored in this study. A peptide cognitive of both SiO2 and TiO2 simultaneously (STB1, ‐CHKKPSKSC‐) is genetically engineered into the C‐terminus of LacI to give LacI‐STB1, and the inserted STB1 peptides in the context of LacI‐STB1 molecules are shown to actively interact with both SiO2 and TiO2. Wild‐type LacI is found to interact with the two surfaces at its flexible N‐terminal DNA binding domain, and LacI‐STB1 exhibits much stronger binding affinity to both surfaces by harnessing a second binding region (STB1 peptide) fused at its C‐terminus. The quantitative analysis of binding kinetics reveals that, compared to wild‐type LacI with one binding region (N‐terminus), two remote binding regions (N‐terminus and C‐terminus) in LacI‐STB1 do not lead to faster adsorption rates to the two surfaces, but remarkably slow down the desorption rates. Finally, using LacI‐STB1 as a linker, the successful assembly of a sandwich nanostructure of DNA/LacI‐STB1/TiO2 NPs is demonstrated using surface plasmon resonance (SPR) measurements and TEM. The demonstrated LacI‐STB1‐mediated assembly of TiO2 NPs on DNA scaffold may provide a generic platform for controlled spatial arrangement of various nanoparticles of engineering interest.
The Role of Processing in the Fabrication and Optimization of Plastic Solar Cells
Authors: Peet Jeffrey , Senatore Michelle L. , Heeger Alan J. , Bazan Guillermo C.
Published: March 2009

The development of high‐efficiency plastic solar cells is rapidly accelerating as the need for economically viable alternative energy sources becomes evident. Polymer‐based bulk‐heterojunction (BHJ) solar cells are attractive in that they can be coated from solution onto flexible substrates by a variety of techniques and thus inexpensive large‐volume manufacturing should be possible. Further, the inherent flexibility of the polymeric materials combined with thin photovoltaic active layers results in devices that can be adapted to a variety of unique aesthetics and form factors. Recent advances in key relationships between thin‐film casting methods, bulk‐heterojunction morphology, and device performance have occurred in tandem with the synthesis of novel polymer semiconductors that possess increased optical‐absorption breadth and optoelectronic performance. This Research News article highlights a few techniques developed to optimize the BHJ nanomorphology and performance of solar cells fabricated by various solution‐processing methods.
The effects of diacylglycerol oil on fat oxidation and energy expenditure in humans and animals
Authors: Hibi Masanobu , Takase Hideto , Meguro Shinichi , Tokimitsu Ichiro
Published: March 2009

Studies in animals and humans indicate that diets containing diacylglycerol (DAG) oil (containing >80% DAG) decrease body weight gain and body fat accumulation, especially visceral fat. Body weight and body fat are controlled by energy expenditure, fat oxidation, fat storage capacity, and appetite control. Recent researches indicate that DAG oil, compared with conventional oils, has distinct metabolic effects. We review the evidence concerning the effects of DAG oil intake on fat oxidation and energy expenditure. In humans, dietary DAG is more susceptible to oxidation, and in animals 1,3‐DAG, a major component of DAG oil, is rapidly oxidized. Short‐term human studies with indirect calorimetry demonstrate greater fat oxidation with DAG oil consumption compared with triacylglycerol (TAG) oil consumption. Furthermore, DAG oil consumption for 14 days stimulates energy expenditure. Based on these reports, enhanced fat oxidation and energy expenditure by daily DAG oil intake could contribute to long‐term reductions in body weight and fat accumulation. The literature provides support for the notion that dietary DAG is more rapidly oxidized than dietary TAG, and that, compared with TAG oil, DAG oil consumption increases whole body fat oxidation. The effects of DAG oil consumption on energy expenditure, however, remain inconclusive. © 2009 International Union of Biochemistry and Molecular Biology, Inc.
Molecular Assembly of an Aptamer–Drug Conjugate for Targeted Drug Delivery to Tumor Cells
Authors: Huang Yu‐Fen , Shangguan Dihua , Liu Haipeng , Phillips Joseph A. , Zhang Xiaoling , Chen Yan , Tan Weihong
Published: March 2009

Special delivery! An aptamer‐directed anticancer drug was molecularly engineered to be delivered to target cells for efficient therapeutic application. The covalent conjugation of drug and aptamer creates alternative opportunities for targeted therapy, as multiple yet specific aptamers can be “generated” relatively easily by cell‐SELEX for any target cells; this demonstrates the full potential of cell‐SELEX as a molecular discovery tool for biomedical studies and drug development.

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The conjugation of antitumor drugs to targeting reagents such as antibodies is a promising method that can increase the efficacy of chemotherapy and reduce the overall toxicity of the drugs. In this study, we covalently link the antitumor agent doxorubicin (Dox) to the DNA aptamer sgc8c, which was selected by the cell‐SELEX method. In doing so, we expected that this sgc8c–Dox conjugate would specifically kill the target CCRF‐CEM (T‐cell acute lymphoblastic leukemia, T‐cell ALL) cells, but with minimal toxicity towards nontarget cells. The results demonstrated that the sgc8c–Dox conjugate possesses many of the properties of the sgc8c aptamer, including high binding affinity (Kd=2.0±0.2 nM) and the capability to be efficiently internalized by target cells. Moreover, due to the specific conjugation method, the acid‐labile linkage connecting the sgc8c–Dox conjugate can be cleaved inside the acidic endosomal environment. Cell viability tests demonstrate that the sgc8c–Dox conjugates not only possess potency similar to unconjugated Dox, but also have the required molecular specificity that is lacking in most current targeted drug delivery strategies. Furthermore, we found that nonspecific uptake of membrane‐permeable Dox to nontarget cell lines could also be inhibited by linking the drug with the aptamer; thus, the conjugates are selective for cells that express higher amounts of target proteins. Compared to the less effective Dox‐immunoconjugates, these sgc8c–Dox conjugates make targeted chemotherapy more feasible with drugs having various potencies. When combined with the large number of recently created DNA aptamers that specifically target a wide variety of cancer cells, this drug‐aptoconjugation method will have broad implications for targeted drug delivery.
Inside Cover: Cytotoxicities and Structure–Activity Relationships of Natural and Unnatural Lamellarins toward Cancer Cell Lines (ChemMedChem 3/2009)
Authors: Chittchang Montakarn , Batsomboon Paratchata , Ruchirawat Somsak , Ploypradith Poonsakdi
Published: March 2009

The inside cover picture shows the structure of lamellarin N as a representative of cytotoxic marine lamellarin alkaloids, together with a potential molecular target, the topoisomerase I–DNA complex. Systematic SAR studies revealed the importance of the substituents for potent cytotoxicity. For more details, see the Full Paper by P. Ploypradith et al. on p. 457 ff.

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Positively Charged Compact Quantum Dot–DNA Complexes for Detection of Nucleic Acids
Authors: Lee Junghan , Choi Youngseon , Kim Junwon , Park Eunjung , Song Rita
Published: March 2009

Selective DNA detection: The fluorescence, from stable cationic QDs, is quenched by 90% on complexation with modified DNA molecules. The QD–DNA probe is capable of detecting pathogenic DNA fragments at concentrations as low as 200 nM in solution and shows selective fluorescence recovery in the presence of target DNA (see spectrum c in figure) vs noncomplementary DNA (spectrum d).

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Novel QD–DNA complexes are prepared by simple electrostatic interaction between pegylated amine‐functionalized CdSe/ZnS quantum dots (QDs) and DNA. The cationic nature of the amine functionality on the QD surface allows for formation of an electrostatic complex with negatively charged DNA. The presence of polyethylene glycol (PEG5000) molecules on the QD leads to enhanced stability and decreased nonspecific adsorption of DNA on the QD surface. Unlike assembly of QD–DNA based on hydrogen bonding, the present QD probes tend to be more strongly stabilized during the hybridization process by increasing the overall negative charges. In addition, the DNA loading efficiency can be modulated by changing the pH of the reaction medium. The fluorescence of the QD is quenched up to 90 % by complexation with 5′‐TAMRA‐modified oligonucleotide (TAMRA=carboxytetramethylrhodamine) through fluorescence resonance energy transfer (FRET). With the FRET pair we selected, the R0 value was calculated to be 5.5 nm and r is about 5 nm. This quenching of QD fluorescence is then reversed on binding of unlabeled target DNA. The maximum recovery of QD fluorescence is 60 %. The QD–DNA probe (5DNA/QD) exhibits selective photoluminescence (PL) recovery in the presence of target oligonucleotide with a PL ratio of 3 for complementary versus noncomplementary. The present QD–DNA probes also show the capability to detect the synthetic 100‐mer oligonucleotide derived from H5N1 influenza virus when present at concentrations as low as 200 nM in the solution.
On the Mechanism of Floating and Sliding of Liquid Marbles
Authors: Bormashenko Edward , Bormashenko Yelena , Musin Albina , Barkay Zahava
Published: March 2009

Little hovercrafts: The mechanisms of floating and sliding of liquid marbles (see picture) are elucidated. It is demonstrated that floating and sliding liquid marbles are separated from their supporting media by an air layer, resembling Leidenfrost drops. An ESEM study of the marble surface shows a rugged surface facilitating the trapping of air.

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The mechanisms of floating and sliding of liquid marbles are studied. Liquid marbles containing CaCl2 and marbles containing NaOH water solutions float on water containing Na2CO3 and an alcoholic solution of phenolphthalein with no chemical reaction. Sliding of liquid marbles, consisting of NaOH water solutions, on polymer substrates coated with phenolphthalein is studied as well. No chemical reaction is observed. These observations supply direct experimental evidence for the suggestion that interfaces are separated by an air layer when marbles roll on solid substrates. It is concluded that a liquid marble rests on hydrophobic particles coating the liquid. In contrast, drops containing an NaOH water solution sliding on superhydrophobic surfaces coated with phenolphthalein leave a colored trace. The mechanism of low‐friction sliding of drops deposited on superhydrophobic surfaces and liquid marbles turns out to be quite different: there is no direct contact between liquid and solid in the case of marbles’ motion.
Infrared Spectroscopy of Fragments from Doubly Protonated Tryptic Peptides
Authors: Bythell Benjamin J. , Erlekam Undine , Paizs Béla , Maître Philippe
Published: March 2009

Most proteins in proteomics are identified from tandem mass spectra of doubly protonated tryptic peptides. Statistical studies indicate that these spectra fall into two distinct classes. IR spectroscopy experiments and DFT calculations performed on model b2 ions show that peptides producing Class I spectra form protonated oxazolone ions (see figure) and not protonated diketopiperazines as proposed elsewhere.

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Cover Picture: Single‐Molecule Fluorescence Studies Reveal Long‐Range Electron‐Transfer Dynamics Through Double‐Stranded DNA (ChemPhysChem 4/2009)
Authors: Kumbhakar Manoj , Kiel Alexander , Pal Haridas , Herten Dirk‐Peter
Published: March 2009

The cover picture shows the results of single‐molecule experiments where fluctuations in the fluorescence emission of a FRET donor could be related to charge transfer through the π‐stack of double‐stranded DNA. The bottom drawing shows a microscopic single‐molecule image of individual DNA probes depicted as green and red spots, indicative of donor and acceptor emission respectively. The overlay on the right is a sketch of a DNA probe with combined electron and energy transfer. The first second of the fluorescence transient shown on top is indicative of energy transfer until the acceptor photo‐bleaches (red). On page 629, M. Kumbhakar, D.‐P. Herten et al. demonstrate that the donor emission shows fluctuations (green) after acceptor bleaching that can be related to charge transfer between donors and acceptors transmitted by the π‐stack of double‐stranded DNA.

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Catalytic Transformation of Waste Polymers to Fuel Oil
Authors: Keane Mark A.
Published: March 2009

Waste not, want not: The increase in waste polymer generation, which continues to exceed recycle, represents a critical environmental burden. However, plastic waste may be viewed as a potential resource and, with the correct treatment, can serve as hydrocarbon raw material or as fuel oil, as described in this Minireview.

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Effective waste management must address waste reduction, reuse, recovery, and recycle. The consumption of plastics continues to grow, and, while plastic recycle has seen a significant increase since the early 1990s, consumption still far exceeds recycle. However, waste plastic can be viewed as a potential resource and can serve, with the correct treatment, as hydrocarbon raw material or as fuel oil. This Minireview considers the role of catalysis in waste polymer reprocessing and provides a critical overview of the existing waste plastic treatment technologies. Thermal pyrolysis results in a random scissioning of the polymer chains, generating products with varying molecular weights. Catalytic degradation provides control over the product composition/distribution and serves to lower significantly the degradation temperature. Incineration of waste PVC is very energy demanding and can result in the formation of toxic chloro emissions. The efficacy of a catalytic transformation of PVC is also discussed.
A model for carbon nanotube interconnects
Authors: Xu Y. , Srivastava A.
Published: March 2009

In this paper, a semi‐classical one‐dimensional (1D) electron fluid model is built that is based on a classical two‐dimensional electron fluid theory taking into account electron–electron repulsive forces, which are significant in 1D system. We have used 1D fluid model to characterize the carbon nanotube (CNT) as interconnects, built a transmission line model and studiedS‐parameters and group delays. We have also comparedS‐parameters and group delays of CNT interconnects with the corresponding parameters of Cu interconnects. The results show that the CNT interconnects exhibit superior performance over the Cu interconnects. The results also suggest using CNT as interconnects for radio frequency (RF)/microwave applications. Copyright © 2009 John Wiley & Sons, Ltd.
Transition and sustainability: empirical analysis of environmental Kuznets curve for water pollution in 25 countries in Central and Eastern Europe and the Commonwealth of Independent States
Authors: Archibald Sandra O. , Bochniarz Zbigniew , Gemma Masahiko , Srebotnjak Tanja
Published: March 2009

This paper examines the effects of political, structural and economic changes on environmental quality in 25 Central and East European countries (CEECs) and the countries of the Commonwealth of Independent States (CIS) using selected water pollution indicators and by testing the environmental Kuznets curve (EKC). Despite substantial research on the transition effects from centrally planned economies and totalitarian political systems to democracy and free market economies, the literature is limited with respect to the short‐ and long‐term environmental impacts. Considering the institutional and structural changes in these economies, rising per capita income and increased trade and investment openness, these countries can be characterized as early, late and non‐liberalizers with respect to the start and continuation of liberalization processes – a critical element of the systemic transformation in the CEECs. While trends in selected economic and social indicators (based on the OECD pressure–state–response framework) show that early liberalizers enjoyed positive gains relative to late liberalizers, the selected environmental indicators do not indicate consistent trends with regard to surface water quality. Among early and late liberalizers, nitrate, orthophosphate and ammonium concentrations decline and converge over time. Phosphorus concentrations initially dropped but then increased again for both groups of countries. Using the indicator of biological oxygen demand (BOD) as the dependent variable and a set of structural and economic measures as the independent variables, our econometric regression model provides some evidence for the EKC hypothesis and estimates the per capita income turning point for industrial BOD effluents to be approximately 3800–5000 USD. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Policy interpretation of human biomonitoring research results in Belgium: priorities and complexity, politics and science
Authors: Keune Hans , Morrens Bert , Springael Johan , Koppen Gudrun , Colles Ann , Loots Ilse , Van Campenhout Karen , Chovanova Hana , Bilau Maaike , Bruckers Liesbeth , Nelen Vera , Baeyens Willy , Van Larebeke Nik
Published: March 2009

Key challenges in the field of environment and health are the interpretation of research data and the translation into policy measures. We present work of the Flemish Centre of Expertise for Environment and Health, working directly for the Flemish government. The centre investigated the complex relation between environmental pollution and human health by measuring pollutants and health effects in (over 4000) Flemish inhabitants, and developed an action plan for the interpretation of these human biomonitoring results for policy‐making. In 2007 the first step of this action plan, the prioritization of research results, was analysed and discussed. We present results of this experience in practice. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Complexation Behavior of a Supramolecular Organic Fluorophore Prepared by Solid‐State Co‐Grinding Crystallization Using 2‐Anthracenecarboxylic Acid and (R)‐1‐(2‐Naphthyl)ethylamine and Its Optical Properties (Eur. J. Org. Chem. 9/2009)
Authors: Imai Yoshitane , Murata Katuzo , Kawaguchi Kakuhiro , Harada Takunori , Nakano Yoko , Sato Tomohiro , Fujiki Michiya , Kuroda Reiko , Matsubara Yoshio
Published: March 2009

The cover picture shows the formation of novel functional supramolecular crystals by simple mixing/co‐grinding of two component crystals. Co‐grinding of crystals of 2‐anthracenecarboxylic acid and (R)‐1‐(2‐naphthyl)ethylamine produces a crystalline supramolecular organic fluorophore having a 21‐helical columnar structure in the solid state, as observed by the change in powder X‐ray diffraction patterns. Details are discussed in the article by Y. Imai, Y. Matsubara et al. on p. 1335 ff.
On the evaluation of seismic response of structures by nonlinear static methods
Authors: Bosco Melina , Ghersi Aurelio , Marino Edoardo M.
Published: March 2009

In the most recent seismic codes, the assessment of the seismic response of structures may be carried out by comparing the displacement capacity, provided by nonlinear static analysis, with the displacement demand. In many cases the code approach is based on the N2 method proposed by Fajfar, which evaluates the displacement demand by defining, as an intermediate step, a single degree‐of‐freedom (SDOF) system equivalent to the examined structure. Other codes suggest simpler approaches, which do not require equivalent SDOF systems, but they give slightly different estimation of the seismic displacement demand. The paper points out the differences between the methods and suggests an operative approach that provides the same accuracy as the N2 method without requiring the evaluation of an equivalent SDOF system. A wide parametric investigation allows an accurate comparison of the different methods and demonstrates the effectiveness of the proposed operative approach. Copyright © 2009 John Wiley & Sons, Ltd.
Suspended sediment transport in a small Mediterranean agricultural catchment
Authors: Estrany Joan , Garcia Celso , Batalla Ramon J.
Published: March 2009

The aim of this study is to analyze suspended sediment transport in a Mediterranean agricultural catchment under traditional soil and water conservation practices. Field measurements were conducted in Can Revull, a small ephemeral catchment (1.03 km2) on the island of Mallorca. This study uses continuous turbidity records to analyse suspended sediment transport regimes, construct and interpret multiple regression models of total suspended sediment concentration (SSC) and of SSC related to stormflow discharge, and assess the sediment loads and yields of three hydrological years (2004–2005 to 2006–2007). An annual average SSC of 17.3 mg l−1, with a maximum of 2270 mg l−1, was recorded in the middle of the winter period when rainfall intensities are high and headwater slopes are ploughed and thus bare. Strong seasonal contrasts of baseflow dynamics associated with different degrees of dilution provide a large scatter in SSC and in the derived rating curves, reflecting that other factors control the supply of suspended sediment. Multiple regression models identify rainfall intensity as the most significant variable in sediment supply. However, under baseflow conditions, physical and biological processes generate sediment in the channel that is subsequently removed during high flow. In contrast, when baseflow is not present, rainfall intensity is the only process that supplies sediment to the channel, mostly from hillslopes. Considering the study period as average in terms of total annual rainfall and intensities, suspended sediment yields were an order of magnitude lower than those obtained in other Mediterranean catchments, a factor that can be related to the historical use of soil conservation practices. Copyright © 2009 John Wiley & Sons, Ltd.
Overexpression of ZNF342 by juxtaposition with MPO promoter/enhancer in the novel translocation t(17;19)(q23;q13.32) in pediatric acute myeloid leukemia and analysis of ZNF342 expression in leukemia
Authors: Poland Kathryn S. , Shardy Deborah L. , Azim Mohammed , Naeem Rizwan , Krance Robert A. , Dreyer ZoAnne E. , Neeley E. Shannon , Zhang Nianxiang , Qiu Yi Hua , Kornblau Steven M. , Plon Sharon E.
Published: March 2009

We report a novel translocation t(17;19)(q22;q13.32) found in 100% of blast cells from a pediatric acute myeloid leukemia (AML) patient. Fluorescence in situ hybridization and vectorette polymerase chain reaction were used to precisely map the chromosomal breakpoint located on the derivative chromosome 17 at 352 bp 5′ of MPO, encoding myeloperoxidase a highly expressed protein in myeloid cells, and 2,085 bp 5′ of ZNF342 on 19q, encoding a transcription factor expressed in human stem cells and previously implicated in mouse models of leukemia. Analysis of RNA levels from the patient sample revealed significant overexpression of ZNF342, potentially contributing to AML formation. This is the first report of a translocation in myeloid leukemia occurring only in the promoter/enhancer regions of the two genes involved, similar to translocations commonly found in lymphoid malignancies. Analysis of ZNF342 protein levels in a large dataset of leukemia samples by reverse phase protein array showed that higher levels of ZNF342 expression in acute lymphoblastic leukemia was associated with poorer outcome (P = 0.033). In the myeloid leukemia samples with the highest ZNF342 expression, there was overrepresentation of FLT3 internal tandem duplication (P = 0.0016) and AML subtype M7 (P = 0.0002). Thus, overexpression of ZNF342 by translocation or other mechanisms contributes to leukemia biology in multiple hematopoietic compartments. © 2009 Wiley‐Liss, Inc.