bluuebunny/crossref_metadata_2025 huggingface dataset:
Ancillary benefits of prenatal maternal serum screening achieved in the California program
Authors: Kazerouni, N. Neely , Currier Robert J. , Hodgkinson Christina , Goldman Sara , Lorey Fred , Roberson Marie
Published: August 2010

Objective

To evaluate the extent of fetal structural abnormalities, other than neural tube and abdominal wall defects (AWDs), identified by California's Prenatal Screening Program.

Methods

The Quad Marker Prenatal Screening records of 516,172 women were examined for screening interpretation and the diagnosis of structural abnormalities detected via follow‐up. Women who were screen‐positive for trisomy 21, trisomy 18, neural tube defects (NTDs) or Smith‐Lemli‐Opitz syndrome (SLOS) received follow‐up services at state‐approved Prenatal Diagnosis Centers (PDCs). Detailed reports of services and diagnostic information were linked in a database to the original screening results.

Results

A total of 26 323 women received follow‐up ultrasound services at the PDCs in the study time period. Of these women, 1085 (4.1%) were identified as having fetuses with significant structural abnormalities, other than NTDs (n = 207) or AWDs (n = 254). In addition to the structural abnormalities, 225 cases of fetal demise, 4 molar pregnancies, 15 cases of twin‐to‐twin transfusion, and 92 cases with placental abnormalities were identified.

Conclusion

While Prenatal Screening Programs do not explicitly screen for structural abnormalities other than NTDs and AWDs, clearly many other structural abnormalities may be associated with a screen‐positive status. Thus, the detection of these additional structural defects can be considered an ancillary program benefit. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis by in situ chemical oxidative polymerization and characterization of polyaniline/iron oxide nanoparticle composite
Authors: Khan Aslam , Aldwayyan Abdullah S , Alhoshan Mansour , Alsalhi Mohamad
Published: August 2010

Polyaniline (PANI) is a well‐studied material and is the pre‐eminent electrically conducting organic polymer with the potential for a variety of applications such as in batteries, microelectronics displays, antistatic coatings, electromagnetic shielding materials, sensors and actuators. Its good environmental as well as thermal stability and electrical conductivity tunable by appropriate doping make PANI an ideal active material for several applications. In this paper, we report the synthesis of water‐dispersible colloidal PANI/iron oxide composite nanoparticles using an in situ chemical oxidation polymerization method in a micellar medium of sodium dodecylsulfate, where the cores (iron oxide) are embedded in a PANI matrix layer. Transmission electron micrographs showed evidence of the formation of an iron oxide core/PANI shell composite with a thin layer of PANI over the iron oxide cores. The results of thermogravimetric, Fourier transform infrared and UV‐visible analysis indicated that the iron oxide nanoparticles could improve the composite thermal stability possibly due to the interaction between iron oxide particles and PANI backbone. We believe that the synthetic route described can also be adapted for the assembly of hierarchical structures of other metal oxides or hydroxides onto various cores. Copyright © 2010 Society of Chemical Industry
Low expression of nicotinic acetylcholine receptor subunit Mdα2 in neonicotinoid‐resistant strains of Musca domestica L.
Authors: Markussen Mette DK , Kristensen Michael
Published: August 2010

BACKGROUND: Neonicotinoid action as well as resistance involves interaction with nicotinic acetylcholine receptors (nAChRs). In the housefly, neonicotinoid resistance also involves cytochrome P450, as indicated by bioassay with synergist as well as altered expression. In bioassay, synergism was only partial and indicated possible target‐site resistance. The nAChR α2 subunit is important in neonicotinoid toxicity to insects, and gene expression of the Mdα2 subunit was investigated in field populations and laboratory strains of neonicotinoid‐resistant and insecticide‐susceptible houseflies, Musca domestica L. The genomic sequence covering exon III–VII of Mdα2 was analysed for mutations.

RESULTS: Gene expression profiling of Mdα2 revealed notable differences between neonicotinoid‐resistant and insecticide‐susceptible houseflies. On average, the neonicotinoid‐resistant field population 766b and the imidacloprid selected strain 791imi had 60% lower copy numbers of Mdα2 compared with the susceptible reference strain. Sequencing of exon III–VII of the Mdα2, encoding acetylcholine binding‐site regions and three out of four transmembrane domains, did not reveal any mutations explaining the increased neonicotinoid tolerance in the strains examined.

CONCLUSION: Previous discoveries and the results of this study suggest that the neonicotinoid resistance mechanism in Danish houseflies involves both cytochrome P450 monooxygenase‐mediated detoxification and reduced expression of the nAChR subunit α2. Copyright © 2010 Society of Chemical Industry
Heating rate effects on the TL characteristics of hot filament CVD diamond film
Authors: Cruz‐Zaragoza E. , Gastélum S. , Quispe R. , Meléndrez R. , Pedroza‐Montero M. , Barboza‐Flores M.
Published: August 2010

The thermoluminescence (TL) glow curve of polycrystalline chemically vapor deposited (CVD) diamond is strongly dependent on the heating rate used. In the present work, we report results about the heating rate effects on a 500 µm hot filament (HF) CVD diamond film grown on silicon substrate using a precursor gas mixture composition of CH4(5 sccm)–CO(10 sccm)–H2(400 sccm). The irradiations were performed with 60Co source. The TL measurements were carried out at different heating rates in the 2–30 K/s range. As the heating rate increases, the maximum TL peak intensity decreases and shifts to higher temperature. The shift was from 578 to 669 K for heating rates of 2 and 30 K/s, respectively. The kinetics parameter and its dependence on the heating rate were evaluated using the Chen's peak shape method and a computerized glow curve deconvolution (CGCD) method.
Linear–supralinear–sublinear beta‐ray dose dependences of TL, OSL and afterglow in undoped CVD diamond
Authors: Chernov V. , Piters T. , May P. W. , Meléndrez R. , Pedroza‐Montero M. , Barboza‐Flores M.
Published: August 2010

The thermoluminescence (TL), optically stimulated luminescence (OSL) and afterglow (AG) properties of chemical vapour deposition (CVD) diamond film irradiated by beta rays with doses from 0.5 to 1000 Gy have been studied. The film (23 µm) was grown for 47 h on monocrystalline silicon. The TL dose responses are similar for all the peaks and exhibit the typical linear–supralinear–sublinear behaviour. The supralinear growth starts at about 1.0 Gy and goes up to 100 Gy. At higher doses the dose responses go to saturation. The AG and OSL dose responses are similar to the TL one and exhibit the supralinear–sublinear behaviour. The linear part (if it exists) is not observed due to low AG and OSL intensity at doses lower than 2.0 Gy. The diamond film that had been irradiated with high doses, partially preheated and irradiated again with low test dose, exhibits increased TL, OSL and AG sensitivity that can be considered as a mixture of the supralinearity and sensitization. Pure sensitization is observed for the 350 and 400 K TL peaks and AG after preheating the sample to temperatures higher than 500 K. This sensitization gradually decreases from 10 to 1 as the preheating increases from 500 to 770 K.
Surface characterization of quinhydrone–methanol and iodine–methanol passivated silicon substrates using X‐ray photoelectron spectroscopy
Authors: Chhabra Bhumika , Weiland Conan , Opila Robert L. , Honsberg Christiana B.
Published: August 2010

Hydrogen‐terminated silicon substrates were passivated with quinhydrone–methanol (QHY/ME) and iodine–methanol (I2/ME), and the chemical changes occurring at the surface were investigated using X‐ray photoelectron spectroscopy (XPS). The XPS surface studies demonstrate that QHY/ME passivation provides reduced oxidation, less carbon contamination, and a chemically inert surface. Electrical characterization also demonstrates higher minority carrier lifetimes of QHY/ME passivated substrates as compared to I2/ME passivated substrates. The quality of surface treatment was also characterized using the contact angle measurement, which confirms the presence of a hydrophobic organic layer on the surface after QHY/ME passivation.

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Si2pXPS spectra of the QHY/ME, I2/ME samples, and H‐terminated silicon. With a peak at 102.9 eV for I2/ME, it is evident that it provides poor surface passivation than QHY/ME where no surface oxidation is observed.
First‐principles study on structural, electronic and magnetic properties of iron nanowire encapsulated in carbon nanotube
Authors: Wang Su‐Fang , Zhang Yan , Chen Li‐Yong , Zhang Jian‐Min , Xu Ke‐Wei
Published: August 2010

The structural, electronic, and magnetic properties of Fe nanowire encapsulated in zigzag CNTs have been investigated systematically using the first‐principles PAW potential within DFT under GGA. Among the seven Fe‐encapsulated C cables, only the (8,0) nanocable is formed endothermically, the other larger cables are formed exothermically. Therefore, it is expected that thicker Fe nanowires would be pulled spontaneously into larger CNTs by forces amounting to a fraction of a nanonewton. The high spin polarization and magnetic moments of the Fe‐encapsulated C cables coming solely from the Fe nanowire imply the Fe‐encapsulated C cables can be appropriate to various applications such as spintronics, high‐density magnetic storage, and magnetically guided drug‐delivery systems.
Transparent conductive CuI thin films prepared by pulsed laser deposition
Authors: Zhu B. L. , Zhao X. Z.
Published: August 2010

Cuprous iodide (CuI) thin films were prepared by a pulsed laser deposition (PLD) technique, and the effects of the laser energy and substrate temperature on the structure and optical–electrical properties were investigated by X‐ray diffraction (XRD), scanning electronic microscopy (SEM), transmittance spectra, and resistivity measurements. At a substrate temperature of room temperature (RT), thin films include highly crystallized and (111)‐orientation preferred γ‐CuI and trace I2O5 phases, and have resistivity of the order of 10−1 Ω cm, average transmittance of about 80% at 410–1000 nm, and the bandgap (Eg) of 3.01 eV at different laser energies. At the same laser energy of 250 mJ/pulse, phase structure, and Eg of the films are uniform as substrate temperature increases to 350 °C, but the resistivity increases to the order of 1 Ω cm and the average transmittance decreases to 60%; the structure and properties of the films completely change as substrate temperature increases to 500 °C. The XRD and transmittance spectra analysis indicate that rudimental oxygen is introduced into CuI thin films, which results in obviously lower resistivity than that of the previously reported value (103 Ω cm). These results imply that the prepared CuI films exhibit excellent transparent conductive properties and can be used in solar cells.
Novel multifunctional materials based on oxide thin films and artificial heteroepitaxial multilayers
Authors: Opel Matthias , Geprägs Stephan , Menzel Edwin P. , Nielsen Andrea , Reisinger Daniel , Nielsen Karl‐Wilhelm , Brandlmaier Andreas , Czeschka Franz D. , Althammer Matthias , Weiler Mathias , Goennenwein Sebastian T. B. , Simon Jürgen , Svete Matthias , Yu Wentao , Hühne Sven‐Martin , Mader Werner , Gross Rudolf
Published: August 2010

Transition metal oxides show fascinating physical properties such as high temperature superconductivity, ferro‐ and antiferromagnetism, ferroelectricity or even multiferroicity. The enormous progress in oxide thin film technology allows us to integrate these materials with semiconducting, normal conducting, dielectric, or non‐linear optical oxides in complex oxide heterostructures, providing the basis for novel multi‐functional materials and various device applications. Here, we report on the combination of ferromagnetic, semiconducting, metallic, and dielectric materials properties in thin films and artificial heterostructures using laser molecular beam epitaxy. We discuss the fabrication and characterization of oxide‐based ferromagnetic tunnel junctions, transition metal‐doped semiconductors, intrinsic multiferroics, and artificial ferroelectric/ferromagnetic heterostructures – the latter allow for the detailed study of strain effects, forming the basis of spin‐mechanics. For characterization we use X‐ray diffraction, SQUID magnetometry, magnetotransport measurements, and advanced methods of transmission electron microscopy (TEM) with the goal to correlate macroscopic physical properties with the microstructure of the thin films and heterostructures.

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The combination of magnetic properties with dielectric, semiconducting, or ferroelectric materials in one and the same material (e.g. magnetic semiconductors (MS) or intrinsic multiferroics) as well as in artificial heterostructures (e.g. ferromagnetic/dielectric heterostructures for magnetic tunnel junctions (MTJs) or artificial multiferroic heterostructures) allows for the design of materials with novel functionalities and provides the basis for various device applications.
Dispersion of single walled carbon nanotubes using poly(3‐dodecylthiophene‐2,5‐diyl)
Authors: Stuparu Alexandrina , Stroh Christophe , Hennrich Frank , Kappes Manfred M.
Published: August 2010

We describe a procedure to suspend single walled carbon nanotubes with poly(3‐dodecylthiophene‐2,5‐diyl) and to purify them using density gradient centrifugation with 2,4,6‐tribromotoluene or dodecyloxy‐2,4,6‐triiodobenzene as density gradient medium. In contrast to fluorene‐based polymers, (n,m) selective solubilization is not observed.
Probing the structure of single‐walled carbon nanotubes by resonant Raman scattering
Authors: Paillet M. , Michel T. , Zahab A. , Nakabayashi D. , Jourdain V. , Parret R. , Meyer J. , Sauvajol J.‐L.
Published: August 2010

We review the main information that we have obtained from combined Raman spectroscopy and electron diffraction experiments on individual free‐standing single‐walled carbon nanotubes. This information concerns: the radial breathing mode vs. diameter relationship; the dependence of the frequency and lineshape of the G‐modes in semiconducting and metallic tubes; the evaluation of the optical transition energies for individual free‐standing SWNTs. From these data, we can define Raman criteria allowing the indexing of carbon nanotubes from their Raman features only. We show the efficiency of this approach to assign the (n,m) indices of individual chiral and achiral single‐walled carbon nanotubes. These criteria are also applied to identify tubes grown on a substrate from a single wavelength Raman experiments. These results obtained on index‐identified individual nanotubes are compared with theoretical predictions.
Tailoring the properties of semiconductor nanowires using ion beams
Authors: Ronning C. , Borschel C. , Geburt S. , Niepelt R. , Müller S. , Stichtenoth D. , Richters J. ‐P. , Dev A. , Voss T. , Chen L. , Heimbrodt W. , Gutsche C. , Prost W.
Published: August 2010

This review demonstrates that ion irradiation is a very useful tool in order to tailor the properties of semiconductor nanowires. Besides optical and electrical doping provided by adequate ion species and ion energies, one can use ion beams also for the controlled shaping of the morphology of nanostructures. Here, one utilizes the commonly as ‘negative’ described characteristics of ion implantation: defect formation and sputtering. We show that ion beams can be even used for an alignment of the nanowires. Furthermore, we report here on several successful experiments in order to modify the electrical and optical properties in a controlled manner of ZnO semiconductor nanowires by the use of transition metals, rare earth elements and hydrogen ions.

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Schematic illustration of ion beam doping of a single contacted nanowire.
Excitonic properties of single CdSe nanowires and coupling to plasmonic nanocavities
Authors: Achtstein Alexander W. , Schoeps Oliver , Artemyev Mikhail V. , Woggon Ulrike
Published: August 2010

Semiconductor nanowires (NWs) have attracted much attention as light emitters at the nanoscale. Due to their unique optical properties, they can be functionalized to hybrid structures in connection with plasmonic nanostructures. CdSe colloidal nanorods (NRs) show a fine structure which is investigated at single NW level. Four types of individual NR spectra have been found and attributed to different neutral, charged and multiexciton states. Additionally, plasmons in single silver NWs have been investigated. Those metallic NWs allow us to study surface plasmon mediated interference phenomena in low‐Q nanocavities. In a third step, metallic NW cavities are functionalized with semiconductor NWs to study exciton–plasmon interaction. Exciton–plasmon–photon conversion and waveguiding can be seen in dependence on wire length and metal–semiconductor spacing in the investigated structure.
Zirconium tungstate/polymer nanocomposites: Challenges and opportunities
Authors: Lind Cora , Coleman Maria R. , Kozy Leah C. , Sharma Gayathri R.
Published: August 2010

Negative thermal expansion (NTE) oxides are interesting materials for use in controlled thermal expansion composites. Cubic ZrW2O8 is one of the most promising candidates due to its strong, isotropic NTE behaviour over a large temperature range. It is easily accessible from a hydrated precursor, ZrW2O7(OH)2 · 2H2O, which enables control of particle size and morphology during the topotactic conversion to the NTE phase. The preparation of high quality composites poses a number of challenges like compatibility of NTE material and composite matrix, stability of the NTE phase and particle morphology and size, which affect mixing and homogeneity. For ZrW2O8/polymer composites, surface modification is necessary to enhance interactions between the polymer matrix and the filler particles. In addition, small particle sizes are crucial to avoid settling of filler particles during polymer processing. This review presents results on the optimization of routes to nano‐ZrW2O8, particle modification to achieve compatibility with polymers, preparation of NTE/polyimide composites and potential problems that can interfere with composite formation.
Thermal strain recovery of anelastic monodomain liquid crystalline networks: Mechanically induced strains ratios
Authors: Ren Wanting , Kline Whitney M. , McMullan Philip J. , Griffin Anselm C.
Published: August 2010

A series of smectic liquid crystalline network polymers was subjected to a large uniaxial stress at temperatures far below the clearing temperature. Their dimensional recovery is anelastic showing substantial retained strain. This process produced a temporally stable monodomain state. Upon heating this monodomain from room temperature, recovery of the original film dimensions occurs. The strain recovery (length) curves show a pronounced curvature as the temperature approaches the smectic–isotropic temperature. It is proposed that nanosegregation of netpoints in the smectic structure is responsible for the anelasticity and that the temperature dependence of the shape recovery is consistent with a balance between enthalpic and entropic forces with temperature. An interesting mechanically induced strains ratio (MISR) was observed on heating these pre‐stressed films. Loss of the monodomain structure near the isotropization temperature is postulated to rationalize the shape of the MISR curves.

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Group IV Nanoparticles: Synthesis, Properties, and Biological Applications
Authors: Fan Jiyang , Chu Paul K.
Published: August 2010

In this review, the emerging roles of group IV nanoparticles including silicon, diamond, silicon carbide, and germanium are summarized and discussed from the perspective of biologists, engineers, and medical practitioners. The synthesis, properties, and biological applications of these new nanomaterials have attracted great interest in the past few years. They have gradually evolved into promising biomaterials due to their innate biocompatibility; toxic ions are not released when they are used in vitro or in vivo, and their wide fluorescence spectral regions span the near‐infrared, visible, and near‐ultraviolet ranges. Additionally, they generally have good resistance against photobleaching and have lifetimes on the order of nanoseconds to microseconds, which are suitable for bioimaging. Some of the materials possess unique mechanical, chemical, or physical properties, such as ultrachemical and thermal stability, high hardness, high photostability, and no blinking. Recent data have revealed the superiority of these nanoparticles in biological imaging and drug delivery.
Capture and Culturing of Living Cells on Microstructured DNA Substrates
Authors: Reisewitz Stephanie , Schroeder Hendrik , Tort Nuria , Edwards Katie A. , Baeumner Antje J. , Niemeyer Christof M.
Published: August 2010

A modular system for the DNA‐directed immobilization of antibodies was applied to capture living cells on microstructured DNA surfaces. It is demonstrated in two different set‐ups, static incubation and hydrodynamic flow, that this approach is well suited for specific capture and selection of cells from culture medium. The adhered cells show intact morphology and they can be cultivated to grow to dense monolayers, restricted to the lateral dimensions of DNA spots on the surface. Owing to the modularity of surface biofunctionalization, the system can readily be configured to serve as a matrix for adhesion and growth of different cells, as demonstrated by specific binding of human embryonic kidney cells (HEK293) and Hodgkin lymphoma L540cy cells onto patches bearing appropriate recognition moieties inside a microfluidic channel. We therefore anticipate that the systems described here should be useful for fundamental research in cell biology or applications in biomedical diagnostics, drug screening, and nanobiotechnology.
Review of literature and resin manufacturer molecular weight‐viscosity relationships for PVC
Authors: Patterson M. C. , Dunkelberger D. L.
Published: August 2010

Accurate molecular weight characterization of PVC is necessary before attempting to modify the properties of the polymer using additives and/or process the compound in some fashion. Commercial PVC resins are characterized by many different dilute solution viscosity methods. Manufacturers characterize their resins using K values, specific viscosity, relative viscosity, viscosity numbers, and inherent viscosity. Each of these methods can vary according to solvent used, testing temperature, and resin concentration. This paper reviews the technical literature and information published by the major PVC resin producers regarding molecular weight characterization. The information in this review should be useful for scientists and engineers in the PVC industry to translate between and among the various test methods for molecular weight characterizations.
Mechanistic aspects of organotin stabilization of PVC
Authors: Burley J. W.
Published: August 2010

Prompted by commercial significance and academic interest, extensive model compound and in‐situ studies of PVC degradation/stabilization appear in the literature. This paper presents the results of some in‐situ studies of the chemical reaction pathways undergone by organotin thioglycollate esters during PVC stabilization. Infrared spectroscopy indicates that in the case of diocyltin bis(isooctylthioglycollate), not only is the mercaptoester/chloride generated, but also the corresponding thioglycollate (Oct2 Sn TG). The extent to which this species is observed is dictated by the processing technique. An attempt is made to correlate the chemical reaction pathway of the organotin compounds with the changes (unsaturation) within the polymer. The possible relevance of these observations to the phenomenon of mono/di synergism is also discussed. While these studies extend our knowledge of the organotin stabilization of PVC, they also show that our understanding is far from complete.
Designing with glass reinforced vinyl composites. I: The effect of time and temperature on modulus values
Authors: Woods M. E. , Rodriguez E. L. , Millward D. R.
Published: August 2010

In designing for stiffness of polymer products, one of the most common questions asked by design engineers is: “What are the effects of time and temperature on the modulus values listed on the product data sheet?” This paper outlines our approach to provide answers for glass reinforced Fiberloc® vinyl composites. Static and dynamic mechanical techniques and time‐temperature superposition principles were used to predict modulus as a function of both temperature and time under load. The predictions are being verified by long‐term creep tests at several temperatures.
Hydrodynamic analysis of calenderable PVC and ABS compounds
Authors: Dotson Seldon L. , Simmons Larry B.
Published: August 2010

Calendering of rigid and semirigid PVC (and ABS) compounds require an understanding of compound rheology and critical processing parameters. Compound rheology is modified with processing aids and lubricants. The choice of processing aid can be critical to achieving the desired rheology needed for calendering. This paper will focus on defining calendering rheology parameters as a function of a super high molecular weight MMA/SAN copolymer processing aid. These rheology parameters will be defined in terms of mill roll gap pressure, adhesive force (compound roll release) melt temperature, and shear rate. The ability to measure these parameters via a computerized two roll mill and relate this data to the actual calendering line will also be discussed.
Expanding PVC as a building material
Authors: Patterson John , Szamborski Gene
Published: August 2010

Rigid vinyl foam can currently be found in applications such as profile, sheet, and foam core pipe, but it is still a curiosity in house siding and other wood replacement applications. This paper looks at the potential for vinyl foam as an alternative for wood, comparing its end‐use capabilities. In addition, the various types of extrusion processes, and formulations, are compared, and the effect of certain types of formulation ingredients on density, surface quality, and other physical properties are described.
Flow properties of long fiber reinforced PP sheets
Authors: Hamada Hiroyuki , Yamaguchi Susumu
Published: August 2010

Long glass fiber reinforced PP sheets, called stampable sheets, are attractive materials because of their light weight, high strength, high moldability, recyclability, and so on. Therefore, stampable sheets have been used in comparatively large products such as bumper beams or seat shells in the car industry. In order to design molds and select adequate molding conditions, flow patterns of stampable sheet must be characterized. In this paper, we carried out the finite element method of the flow of stampable sheet, using the lamination theory. One‐ply sheet can be regarded as two PP resin layers and one reinforced layer. Large deformation analysis was performed with heat condition analysis, and the material was modeled as an elastic‐perfect plastic material. In‐plane and out‐plane flow patterns were analyzed. In the former, the material flow occurred in the plane, as in the fabrication of plane sheet, and in the latter, the flow pattern was as in the case of ribs or boss parts. Numerical results suggested that in‐plane flow was characterized by slippage flow, and out‐plane flow was characterized by squeezing flow.
Electrically active nanomaterials as improved neural tissue regeneration scaffolds
Authors: Seil Justin T. , Webster Thomas J.
Published: August 2010

Numerous biomaterials have provided promising results toward improving the function of injured nervous system tissue. However, significant hurdles, such as delayed or incomplete tissue regeneration, remain toward full functional recovery of nervous system tissue. Because of this continual need for better nervous system biomaterials, more recent approaches to design the next generation of tissue engineering scaffolds for the nervous system have incorporated nanotechnology, or more specifically, nanoscale surface feature dimensions which mimic natural neural tissue. Compared to conventional materials with micron‐scale surface dimensions, nanomaterials have exhibited an ability to enhance desirable neural cell activity while minimizing unwanted cell activity, such as reactive astrocyte activity in the central nervous system. The complexity of neural tissue injury and the presence of inhibitory cues as well as the absence of stimulatory cues may require multifaceted treatment approaches with customized biomaterials that nanotechnology can provide. Combinations of stimulatory cues may be used to incorporate nanoscale topographical and chemical or electrical cues in the same scaffold to provide an environment for tissue regeneration that is superior to inert scaffolds. Ongoing research in the field of electrically active nanomaterials includes the fabrication of composite materials with nanoscale, piezoelectric zinc oxide particles embedded into a polymer matrix. Zinc oxide, when mechanically deformed through ultrasound, for example, can theoretically provide an electrical stimulus, a known stimulatory cue for neural tissue regeneration. The combination of nanoscale surface dimensions and electrical activity may provide an enhanced neural tissue regeneration environment; such multifaceted nanotechnology approaches deserve further attention in the neural tissue regeneration field. WIREs Nanomed Nanobiotechnol 2010 2 635–647

This article is categorized under:

Implantable Materials and Surgical Technologies > Nanomaterials and Implants

Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease

Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement
Novel DNA materials and their applications
Authors: Yang Dayong , Campolongo Michael J. , Nhi Tran Thua Nguyen , Ruiz Roanna C. H. , Kahn Jason S. , Luo Dan
Published: August 2010

The last two decades have witnessed the exponential development of DNA as a generic material instead of just a genetic material. The biological function, nanoscale geometry, biocompatibility, biodegradability, and molecular recognition capacity of DNA make it a promising candidate for the construction of novel functional nanomaterials. As a result, DNA has been recognized as one of the most appealing and versatile nanomaterial building blocks. Scientists have used DNA in this way to construct various amazing nanostructures, such as ordered lattices, origami, supramolecular assemblies, and even three‐dimensional objects. In addition, DNA has been utilized as a guide and template to direct the assembly of other nanomaterials including nanowires, free‐standing membranes, and crystals. Furthermore, DNA can also be used as structural components to construct bulk materials such as DNA hydrogels, demonstrating its ability to behave as a unique polymer. Overall, these novel DNA materials have found applications in various areas in the biomedical field in general, and nanomedicine in particular. In this review, we summarize the development of DNA assemblies, describe the innovative progress of multifunctional and bulk DNA materials, and highlight some real‐world nanomedical applications of these DNA materials. We also show our insights throughout this article for the future direction of DNA materials. WIREs Nanomed Nanobiotechnol 2010 2 648–669

This article is categorized under:

Diagnostic Tools > Biosensing

Nanotechnology Approaches to Biology > Cells at the Nanoscale

Implantable Materials and Surgical Technologies > Nanomaterials and Implants

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Synthesis Characterization, X‐ray Structures, and Solution Studies of Dinuclear Zinc(II) Complexes of Acyclic Schiff Base Ligands
Authors: Hosseini‐Yazdi Seyed A. , Khandar Ali A. , Tabatabai Mir Kh. , Noohinejad Leila
Published: August 2010

Dizinc(II) complexes of two acyclic Schiff‐base ligands L1– and L2– were synthesized by Schiff base condensation of 2‐[3‐(2‐formylphenoxy)‐2‐hydroxypropoxy]benzaldehyde (PL) with 1,2‐diaminopropane and 1,2‐diaminoethane, respectively, in the presence of zinc(II) salts. The isolation of a selection of 2:1 (metal:ligand) complexes of zinc(II) was carried out and conductance measurements, IR, UV/Vis absorption, and fluorescence emission spectroscopy, as well as X‐ray diffraction were employed to probe the nature of the respective complexes in both solid and solution states. The molecular structure of [Zn2L1(NO3)3] (1) complex consists of two six‐coordinate atoms, which are bridged by the deprotonated hydroxy group and one 1,3‐bridging nitrate anion. The structure of [Zn2L2(NO3)(H2O)2](NO3)2·CH3OH (3) consists of a dizinc cation and two nitrate anions as counterions. In compound 3, each zinc atom is bound to water instead of a terminal nitrate anion in a distorted octahedral arrangement. The intermetallic separation distance of Zn···Zn in 3 (3.376 Å) is slightly smaller than 1 (3.403 Å) and is similar to that found in zinc phosphotriesterase (3.5 Å). The π–π interactions between the benzene rings of adjacent molecules in 3 are stronger than in 1.
Three Octacyanometallate‐Based LnIII–MV (Ln = La, Ce; M = Mo, W) Bimetallic Assemblies with a One‐Dimensional Rope‐Ladder Chain Structure
Authors: Qian Su‐Yan , Zhou Hu , Zhang Ying , Yuan Ai‐Hua
Published: August 2010

Three octacyanometallate‐based hetero‐bimetallic complexes, [Ln(H2O)4(CH3CN)2][M(CN)8]·CH3CN [Ln = La, M = Mo(1), W(2); Ln = Ce, M = W(3)], were synthesized and characterized structurally. Single‐crystal X‐ray analysis reveals that 1–3 are isomorphous and consist of infinite one‐dimensional (1D) 3,3 rope‐ladder chains, in which the 12‐membered puckered square Ln2M2(CN)4 is the basic building unit. The 1D chains are further linked through interchain hydrogen bonds, resulting in a three‐dimensional (3D) supramolecular network.
A Series of Transition Metal Coordination Polymers Bearing 1,4‐Phenylenediacetate
Authors: Chen Zilu , Zhao Qin , Xiong Wei , Zhang Zhong , Liang Fupei
Published: August 2010

The reactions of transition metal salts or hydroxide with 1,4‐phenylenediacetic acid (H2PDA) in the presence of ancillary ligands 4,4′‐bipyridine (4,4′‐bpy) or imidazole (Im) produced five coordination polymers with the empirical formula [M(PDA)(4,4′‐bpy)(H2O)2]n [M = Mn (1), Ni (2)], [Cu(PDA)(4,4′‐bpy)]n·2nH2O (3), [Ni(PDA)(Im)2(H2O)2]n·nH2O (4), and [Cu(PDA)(Im)2]n·2nH2O (5). Their structures were determined by single‐crystal X‐ray diffraction analyses. The isomorphous 1 and 2 present a two‐dimensional sheet constructed by two kinds of one‐dimensional chains of –NiII–PDA2––NiII– and –NiII–4,4′‐bpy–NiII–. Compound 3 features dinuclear subunits, which are further connected by two PDA2– ligands and two 4,4′‐bpy ligands along (001) and (011) directions, respectively, to build a two‐dimensional sheet with the topology (42.67.8)(42.6) different from those of 1 and 2. Both 4 and 5 show one‐dimensional chain structure. The difference of compound 4 and 5 is that the two carboxylato groups of PDA2– in 4 adopt monodentate coordination modes, whereas the two carboxylato groups of PDA2– in 5 chelate to the metal ions. Magnetic susceptibility data of 1 were measured. Magnetically, 1 presents a one‐dimensional chain with a weak antiferromagnetic interaction (J =–0.064 cm–1) between the intrachain MnII atoms mediated by 4,4′‐bpy.
Using Taguchi Robust Design Method to Develop an Optimized Synthesis Procedure for Nanocrystals of ZSM‐5 Zeolite
Authors: Abrishamkar Maryam , Azizi Seyed Naser , Kazemian Hossein
Published: August 2010

The effects of TPAOH/SiO2, H2O/SiO2, SiO2/Na2O and SiO2/Al2O3 ratios in the initial synthetic mixture on the crystallization of nanoparticles of ZSM‐5 zeolite under atmospheric pressure were studied. A Taguchi orthogonal experimental design with three levels of the above‐mentioned parameters was used to optimize the experiment parameters by the analysis of variances (ANOVA). Applying the Taguchi method significantly reduced the time and cost for optimization. The obtained products were characterized by scanning electron microscopy, X‐ray diffraction and FT‐IR spectroscopy. As a result of the Taguchi analysis TPAOH/SiO2 followed by SiO2/Al2O3 was the most influencing parameters for the synthesis of nanosized ZSM‐5 crystals.
Syntheses, Crystal Structures, and Physico‐Chemical Studies of Sodium and Potassium Alcoholates Bearing Thienyl Substituents and their Derived Luminescent Samarium(III) Alkoxides
Authors: Veith Michael , Belot Céline , Huch Volker , Guyard Laurent , Knorr Michael , Khatyr Abderrahim , Wickleder Claudia
Published: August 2010

The synthesis, structural characterisation, electrochemistry, and luminescence properties of a series of alkali metal alcoholates and samarium(III) alkoxides with thiophene‐based OR substituents are presented. The alkali metal alcoholates 7–15 were obtained by deprotonation of the carbinol with NaH or KH. Their molecular structures consist of tetranuclear alkali metal alcoholates with a distorted cubane‐like M4O4 core (X‐ray structure analyses). Each alkali metal is surrounded by three carbinolate ligands and (depending on the derivative) by additional tetrahydrofuran molecules. The mononuclear samarium alkoxides {Sm[OC(C4H3S)3]3(thf)3}·thf (16) and {Sm[OC(C16H13S)]3(thf)3}·thf (17) were synthesised by the salt metathesis reactions between {[KOC(C4H3S)3]4(thf)2}·thf (7), [NaOC(C4H3S)3]4(thf)2 (8) or {[KOC(C16H13S)]4(thf)3}·1/2thf (11), respectively, and SmCl3 in thf solution. The molecular structures of these air‐sensitive base adducts have been determined by single crystal X‐ray crystallography and reveal an approximately octahedral coordination sphere around the samarium metal atoms with three methoxido ligands and three facially arranged tetrahydrofuran molecules. The electrochemical properties are essentially dominated by the oxidation of the thienyl units. The emission spectra of the carbinols and their derived potassium and sodium compounds display broad bands attributed to the π* → π transitions of the aromatic ligands. Luminescence studies performed on complexes 16 and 17 reveal the typical f–f transitions of the SmIII ion. The photophysical data suggest that an energy transfer from the ligand to the metal atom operates.
Einfluss von H‐Brückenbindungen auf die Jahn–Teller‐Verzerrung in den Kettenstrukturen von 2,2′‐bipyMn(H2PO4)F2·H2O und 2,2′‐bipyMn(H2PO4)2F
Authors: Stief Ronald , Massa Werner
Published: August 2010

In the system 2,2′‐bipyridine/MnIII/HF/H3PO4/H2O two compounds with chain structures could be prepared and characterised by X‐ray structure analyses. 2,2′‐bipyMn(H2PO4)F2·H2O (1): monoclinic, twinned, space group P21/c, Z = 4, a = 6.7883(4), b = 10.9147(5), c = 17.8102(8) Å, β = 100.142(4)°, R = 0.0328. 2,2′‐bipyMn(H2PO4)2F (2): triclinic, space group P$\bar{1}$, Z = 2, a = 6.675(1), b = 10.715(1), c = 11.013(1) Å, α = 107.595(9)°, β = 90.994(9)°, γ = 95.784(8)°, R = 0.0252. Both compounds show chain structures with trans‐bridging dihydrogenphosphate ligands and bipy and two fluorine ligands for (1), or bipy, fluorine and an additional dihydrogenphosphate, respectively, for (2) in equatorial positions. Due to the pseudo‐Jahn–Teller effect, MnIII shows elongated octahedral coordination with ferrodistortive ordering along the chain direction. The distortion is remarkably higher in (1) than in (2). This is discussed in context with additional hydrogen bonds along the chain in (2).
The Platinum(II) Salt Pt(H2O)4(SbF6)2
Authors: Seppelt Konrad
Published: August 2010

The platinum(II) salt Pt(H2O)4(SbF6)2 is a stable compound. In the solid state the compound consists of isolated Pt(H2O)42+ cations and SbF6– anions. Space group P$\rm P\bar1$, Z = 1, lattice dimensions at 133 K: a = 503.7(2), b = 783.4(2), c = 854.1(2) pm, α = 69.03(2), β = 83.36(2), γ = 75.88(2).
[2‐{E(CH2CH2)2NCH2}C6H4]nBiX3–n (E = O, NMe; X = Cl, Br, I; n = 1–3) and [2‐(Me2NCH2)C6H4]BiBr2 – New Hypervalent Organobismuth(III) Compounds
Authors: Breunig Hans J. , Nema Mihai G. , Silvestru Cristian , Soran Albert , Varga Richard A.
Published: August 2010

The homoleptic [2‐{E(CH2CH2)2NCH2}C6H4]3Bi [E = O (1), MeN (2)], the chlorides [2‐{E(CH2CH2)2NCH2}C6H4]2BiCl [E = O (3), MeN (4)] and the dichlorides [2‐{E(CH2CH2)2NCH2}C6H4]BiCl2 [E = O (5), MeN (6)] were synthesized by reaction of the corresponding ortho‐lithium derivative with BiCl3 in corresponding molar ratios. The dihalides [2‐{E(CH2CH2)2NCH2}C6H4]BiX2 [X = Br, E = O (7), MeN (9); X = I, E = O (8), MeN (10)] as well as [2‐(Me2NCH2)C6H4]BiBr2 (11) were obtained by halide exchange reactions between RBiCl2 and excess aqueous solution of KX. The compounds were characterized by multinuclear (1H, 13C) NMR spectroscopy and mass spectrometry. The crystal and molecular structures of 1–5 and 11 were determined by single‐crystal X‐ray diffraction. In all compounds the (C6H4CH2)N nitrogen atoms are coordinated to bismuth. The crystals of 1 and 2, as well as those of the chlorides 3 and 4, contain discrete molecules. For R3Bi intramolecular N→Bi interactions of medium strength [Bi(1)–N(1) 3.170(7) Å for 1 and 3.211(5) Å for 2] result in an overall distorted octahedral (C,N)3Bi core. In the monochlorides one nitrogen atom is strongly coordinated to the bismuth atom [2.660(11) Å for 3 and 2.744(14) Å for 4] trans to the halogen atom, whereas the second one is involved in a weaker intramolecular N→Bi interaction [3.095(11) Å for 3 and 3.061(14) Å for 4] trans to a carbon atom. The overall (C,N)2BiCl core is distorted square‐pyramidal. The crystals of the monohalides 5 and 11 contain discrete dimer units. The pendant arm nitrogen atom is strongly coordinated [2.548(9) Å for 5 and 2.485(13) Å for 11] trans to the bridging halogen atom, thus resulting in an overall distorted square‐pyramidal (C,N)BiX3 (X = Cl, Br) core. The six‐membered morpholinyl and piperazinyl rings in 1–5 adopt the chair conformation, which prevents intramolecular coordination of the oxygen or N(Me) nitrogen atoms to bismuth. Supramolecular architectures based on intermolecular Bi···Br interactions, Cl···H, and Br···H contacts are formed in the crystals of 3, 5, and 11.
Synthesis and Characterization of Gold(I) and Gold(III) Complexes Derived from Benzimidazolin‐2‐ylidene Ligands
Authors: Jahnke Mareike C. , Pape Tania , Hahn F. Ekkehardt
Published: August 2010

Substitution of the chlorido ligand in (N,N′‐dialkylbenzimidazolin‐2‐ylidene)gold(I) chlorides (alkyl = methyl, ethyl, propyl, butyl) succeeded by treatment of the gold chlorido complexes with lithium bromide in acetone, which leads to the gold complexes of the type [AuBr(NHC)] (1–4). Furthermore, the Au–Ccarbene bond in complexes 1–4 is inert towards a change of the oxidation state of the metal atom. Complexes 1–4 were oxidized chemically with elemental bromine leading to the gold(III) carbene complexes of the type [AuBr3(NHC)] (5–8). The molecular structures of the gold(I) complexes 1, 2, and 4, which exhibit a linear topology, are presented together with the two molecular structures of the square‐planar gold(III) complexes 6 and 8.
Synthesis and Structural Characterisation of an Isomorphous Series of Bis(imidazolin‐2‐imine) Metal Dichlorides Containing the First Row Transition Metals Mn, Fe, Co, Ni, Cu and Zn
Authors: Glöge Thomas , Petrovic Dejan , Hrib Cristian G. , Daniliuc Constantin , Herdtweck Eberhardt , Jones Peter G. , Tamm Matthias
Published: August 2010

The bis(imidazolin‐2‐imine) ligand N,N′‐bis(1,3‐diisopropyl‐4,5‐dimethylimidazolin‐2‐ylidene)‐1,2‐ethanediamine (BLiPr) was used to synthesize a complete series of transition metal dichloride complexes of the type [(BLiPr)MCl2] with M = Mn, Fe, Co, Ni, Cu, Zn. The molecular structure of each complex was established by X‐ray diffraction analysis; the complexes are isomorphous and crystallize in the monoclinic space group C2/c, which allows comparison of their structural parameters in a constant packing environment. The complexes exhibit distorted tetrahedral coordination around the metal atoms with the dihedral angles between the MN2 and MCl2 planes ranging from 53.9° (M = Cu) to 75.5° (M = Zn).
Transition‐Metal Complexes Based on the 1,3,5‐Triethynyl Benzene Linking Unit
Authors: Packheiser Rico , Rüffer Tobias , Ecorchard Petra , Lang Heinrich
Published: August 2010

The synthesis of a unique series of heteromultinuclear transition metal compounds is reported. Complexes 1‐I‐3‐Br‐5‐(FcC≡C)‐C6H3 (4), 1‐Br‐3‐(bpy‐C≡C)‐5‐(FcC≡C)‐C6H3 (6), 1,3‐(bpy‐C≡C)2‐5‐(FcC≡C)‐C6H3 (7), 1‐(XC≡C)‐3‐(bpy‐C≡C)‐5‐(FcC≡C)‐C6H3 (8, X = SiMe3; 9, X = H), 1‐(HC≡C)‐3‐[(CO)3ClRe(bpy‐C≡C)]‐5‐(FcC≡C)‐C6H3 (11), 1‐[(Ph3P)AuC≡C]‐3‐[(CO)3ClRe(bpy‐C≡C)]‐5‐(FcC≡C)‐C6H3 (13), 1‐[(Ph3P)AuC≡C]‐3‐(bpy‐C≡C)‐5‐(FcC≡C)‐C6H3 (14), [1‐[(Ph3PAuC≡C]‐3‐[{[Ti](C≡CSiMe3)2}Cu(bpy‐C≡C)]‐5‐(FcC≡C)‐C6H3]PF6 (16), and [1,3‐[(tBu2bpy)2Ru(bpy‐C≡C)]2‐5‐(FcC≡C)‐C6H3](PF6)4 (18) (Fc = (η5‐C5H4)(η5‐C5H5)Fe, bpy = 2,2′‐bipyridiyl‐5‐yl, [Ti] = (η5‐C5H4SiMe3)2Ti) were prepared by using consecutive synthesis methodologies including metathesis, desilylation, dehydrohalogenation, and carbon–carbon cross‐coupling reactions. In these complexes the corresponding metal atoms are connected by carbon‐rich bridging units comprising 1,3‐diethynyl‐, 1,3,5‐triethynylbenzene and bipyridyl units. They were characterized by elemental analysis, IR and NMR spectroscopy, and partly by ESI‐TOF mass spectrometry., The structures of 4 and 11 in the solid state are reported. Both molecules are characterized by the central benzene core bridging the individual transition metal complex fragments. The corresponding acetylide entities are, as typical, found in a linear arrangement with representative M–C, C–CC≡C and C≡C bond lengths.
K3[C3N3(COO)3]·2H2O – Crystal Structure of a New Alkali Derivative of the Multidentate Ligand Triazine Tricarboxylate
Authors: Makowski Sophia J. , Hörmannsdorfer Michael , Schnick Wolfgang
Published: August 2010

Potassium‐1,3,5‐triazine‐2,4,6‐tricarboxylate dihydrate K3[C3N3(COO)3]·2H2O was obtained by saponification of the respective ethyl ester in aqueous solution under mild conditions and subsequent crystallization at 4 °C. The crystal structure of the molecular salt was elucidated by single‐crystal X‐ray diffraction [P$\bar{1}$, a = 696.63(14), b = 1748.5(3), c = 1756.0(3) pm, α = 119.73(3), β = 91.96(3), γ = 93.84(3)°, V = 1847.6(6)·106 pm3, Z = 6, T = 200 K]. Perpendicular to [100] the triazine tricarboxylate and potassium ions are arranged in layers alternating with layers of crystal water molecules. Two thirds of the triazine tricarboxylate units form hexagonal channels being filled with the remaining triazine tricarboxylate molecules. K3[C3N3(COO)3]·2H2O was additionally investigated by means of FTIR spectroscopy, TG and DTA measurements.
[(BeCl2)2(18‐Krone‐6)] und sein Hydrolyseprodukt [{Be3(μ‐OH)3(H2O)6}‐(18‐Krone‐6)]Cl3·3H2O: Kristallstrukturen und DFT‐Rechnungen
Authors: Putcha Ralph , Kolbig René , Weller Frank , Neumüller Bernhard , Massa Werner , Dehnicke Kurt
Published: August 2010

Beryllium dichloride reacts in dichloromethane suspension with 18‐crown‐6 to give the molecular centrosymmetric complex [(BeCl2)2(18‐crown‐6)] (1), which was characterized by single‐crystal X‐ray diffraction, by vibrational spectroscopy (IR, Raman), and by DFT calculations. 1 crystallizes monoclinically in the space group P21/n with Z = 2. Lattice dimensions at 100(2) K: a = 747.5(1), b = 1373.9(1), c = 899.1(1) pm, β = 94.84(1)°, R1 = 0.0233., Exposition of 1 to moist atmosphere leads to single crystals of [{Be3(μ‐OH)3(H2O)6}(18‐crown‐6)]Cl3·3H2O (2·3H2O), which are characterized by X‐ray diffraction. 2 crystallizes in the triclinic space group P$\rm P\bar1$ with Z = 2. Lattice dimensions at 100(2) K: a = 1046.04(9), b = 1236.12(11), c = 1275.72(13) pm, α = 80.233(8)°, β = 66.439(7)°, γ = 80.053(7)°, R1 = 0.0476.