bluuebunny/crossref_metadata_2025 huggingface dataset:
Mobility of Green Fluorescent Protein in Hydrogel‐Based Drug‐Delivery Systems Studied by Anisotropy and Fluorescence Recovery After Photobleaching
Authors: Bertz Andreas , Ehlers Jan‐Eric , Wöhl‐Bruhn Stefanie , Bunjes Heike , Gericke Karl‐Heinz , Menzel Henning
Published: December 2012

Modified hydroxyethyl starch is photo‐crosslinked in the presence of a green fluorescent protein (GFP) (mTagGFP) to obtain loaded hydrogels as model for a drug‐delivery system. An important factor for the protein release is the crosslinking density since a dense network should lead to hindered diffusion. To obtain information on the rotational and translational diffusion of GFP in the hydrogel, mTagGFP is analyzed by fluorescence anisotropy and fluorescence recovery after photo‐bleaching experiments using two‐photon excitation. The mTagGFP shows a viscosity‐retarded rotational and strongly hindered translational diffusion, depending on the polymer concentration. A comparison of anisotropy studies with mTagGFP‐loaded microparticles and hydrogel disks allows the polymer concentration to be determined for the microparticles, which has been previously unknown.

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Flexible Pressure Sensor Based on a Poly(VDF‐TrFE) Nanofiber Web
Authors: Ren Guangyi , Cai Fanyi , Li Baozhang , Zheng Jianming , Xu Chunye
Published: December 2012

During electrospinning, P(VDF‐TrFE), an electroactive polymer, acquires special electrical and mechanical properties. The development of a flexible, breathable pressure sensor based on P(VDF‐TrFE) nanofiber webs is reported that shows promise for use in human‐centered applications. The P(VDF‐TrFE) nanofiber webs are produced by electrospinning. The morphology and microstructure of webs are characterized using SEM, XRD, and ATR‐FTIR spectroscopy. Flexible pressure sensors are developed that are suitable for incorporation into fabrics and, using a custom‐made setup, is is demonstrated that they have a maximum sensitivity of 60.5 mV · N−1.

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The Effect of Phase Morphology on the Thermal Stability of Epoxy/Poly(L‐lactide) Blends Before and After Curing
Authors: Calafel M. I. , Remiro P. M. , Cortázar M. M. , Calahorra M. E.
Published: December 2012

Summary: Diglicidylether of bisphenol A (DGEBA) was blended with poly(L‐lactic) acid (PLLA) and cured with diaminodiphenylmethane (DDM). The uncured blends were miscible but became immiscible upon curing. The relationship between phase morphology and thermal stability was investigated. It was found that the thermal degradation of uncured DGEBA, PLLA and their blends occurred mainly through one step. PLLA and uncured DGEBA were mutually destabilized. This is probably due to chemical effects, such as some sort of interaction between the products of degradation of DGEBA and PLLA in the miscible blend. On the other hand, the biphasic cured DGEBA/PLLA blends displayed two degradation stages associated to decomposition of two phases, one rich in PLLA and the other in DGEBA. The temperature at which weight loss begins in the blend is intermediate to the temperature of the neat components. This was attributable to physical effects.
Effects of Bioactive Glass Particles on the Mechanical and Thermal Behavior of Poly(ε‐caprolactone)
Authors: Diamanti E. , Sarasua J. R.
Published: December 2012

Summary: Poly(ε‐caprolactone)/Bioactive glass (BG) composites were prepared to study the effects of bioactive glass on mechanical and thermal behavior of poly(ε‐caprolactone) (PCL). Composites were fabricated using a solvent casting/sonication technique. Composite characterization was conducted by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and tensile tests. Interphase adhesion between filler and matrix, a prerequisite for good mechanical properties, was evaluated by dynamic mechanical analysis (DMA). The obtained results showed that BG leaded to an acceleration of the composite thermal degradation accompanied by a general enhancement of the mechanical properties.
Bimodal Poly(propylene) through Binary Metallocene Catalytic Systems as an Alternative to Melt Blending
Authors: Moya E. López , Van Grieken R. , Carrero A. , Paredes B.
Published: December 2012

Summary: Propylene was polymerized by three homogenous metallocene catalytic systems: rac‐Me2Si (Ind)2ZrCl2 (CAT‐1), rac‐Et(Ind)2ZrCl2 (CAT‐2) and rac‐Me2Si(2‐Me‐benzoind)2ZrCl22ZrCl2 (CAT‐3) at 50 °C. In function of the molecular‐average weight results of poly(propylene)s obtained, rac‐Et(Ind)2ZrCl2 (CAT‐2) and rac‐Me2Si(2‐Me‐benzoind)2ZrCl2 (CAT‐3) were combined in different proportions (wt %/wt %) of (CAT‐2/CAT‐3) for obtaining a new poly(propylene) with a bimodal molecular weight distribution consisting in clearly separated low and high molecular weight polymer fractions with a difference between them of an order of magnitude. The polymers obtained were compared with those coming from melt mixing of two poly(propylene)s with different molecular weights in an extruder. Both methods allow obtaining bimodal poly(propylene)s, but polymer melt blending shows partial miscibility effects and less crystallinity while binary catalytic systems have several advantages such as lower costs and easier to process that can be controlled to tailor properties together with intimate mixing of high and low molecular weight components.
Physical Aging in Poly(L‐lactide) and its Multi‐Wall Carbon Nanotube Nanocomposites
Authors: Lizundia E. , Sarasua J. R.
Published: December 2012

Summary: In this work the effects of the structure evolution of neat PLLA and its multi‐wall carbon nanotube nanocomposites at an aging temperature of 45 °C (Tg‐12 °C) have been investigated. The analysis of enthalpy relaxation rate (βH) of composites by means of differential scanning calorimetry (DSC) reveals the existence of a critical concentration of 1.25–2.5 wt. % in which aging rate reaches a mi–imum value of 1.351 J/g. Mechanical tests showed that neat polymer is much more sensitive to the aging process than the reinforced one. As shown by transmission electron microscopy (TEM) all the samples present randomly dispersed nanotubes, yielding an agglomerated structure at MWCNT contents exceeding 1.25–2.5 wt.%. The obtained results are explained from the viewpoint of polymer/filler interfacial effects that perturb the structural relaxation of glassy polymer due to the drastic reduction on the molecular mobility of polymer chains in the vicinity of carbon nanotube surfaces. In this way, nanocomposite approach represents an efficient strategy to successfully reduce the physical aging process of polymers.
Unimolecular Nanoparticles via Carbon‐Carbon “Click” Chemistry for All‐Polymer Nanocomposites
Authors: Khanjani P. , Perez‐Baena I. , Buruaga L. , Pomposo J. A.
Published: December 2012

Summary: We report for the first time the synthesis of unimolecular polystyrene‐based nanoparticles (PS‐NPs) under normal air atmosphere by direct carbon‐carbon “click” chemistry (i.e., “self‐click” chemistry). First, statistical poly(styrene‐co‐4‐vinylbenzyl chloride) copolymers synthesized by RAFT polymerization were decorated in a facile manner with alkyne groups by reaction with potassium propiolate, providing well‐defined nanoparticle precursors (PS‐Prec). Next, individual PS‐Prec chains were collapsed irreversibly to unimolecular nanoparticles of ca. 12 nm in size by intrachain Cu(II)‐catalyzed alkyne dimerization under high‐dilution conditions, as revealed by SEC, H1‐NMR, DLS and TEM measurements. Based on predictions from a recent compressible thermodynamic model, the resulting nanoparticles could be promising materials for the development of homogeneous, miscible PS‐NPs / polycarbonate all‐polymer nanocomposites.
Hydrogen Bonds in Blends of Poly(vinylphenol‐co‐methylmethacrylate)/Poly(vinylmethylketone)
Authors: Benabdelghani Z. , Etxeberria A.
Published: December 2012

Summary: The hydrogen bonding and phase behaviour of blends of poly(vinylphenol‐co‐methylmethacrylate) (PVPhMMA50) containing 50% of methyl methacrylate with poly(vinylmethylketone) (PVMK) were investigated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). It was shown that all the blends have a single glass transition over the entire composition range. The FTIR study reveals the presence of intermolecular hydrogen‐bonding interactions occurring between hydroxyl and carbonyl groups of vinylphenol (PVPh) and (PVMK) and intensified when the amount of PVMK increased in blend. A new band characterizing these interactions at 1713 cm−1 was observed. Furthermore, the quantitative FTIR study carried out for PVPhMMA50/PVMK blends was also performed for the vinylphenol and vinylmethylketone functional groups.
Thermodynamic Study of Blends of Poly(4‐vinylphenol‐co‐methyl methacrylate)/Poly(styrene‐co‐4‐vinylpyridine) by Inverse Gas Chromatography
Authors: Benabdelghani Z. , Belabed Ch. , Etxeberria A.
Published: December 2012

Summary: Differential scanning calorimetry (DSC) and inverse gas chromatography (IGC) were used to determine the physicochemical properties of blends of poly(4‐vinylphenol‐co‐methyl methacrylate) (PVPhMMA50) containing 50% of methyl methacrylate with poly(styrene‐co‐4‐vinylpyridine) (PS4VPy 30) containing 30 mol% of 4‐vinylpyridine. Specific retention volumes (Vg) and Flory‐Huggins interaction parameter ($\chi _{1i} $) for eight probes with different polarities were calculated at the 180–200 °C temperature range using PVPhMMA50, PS4VPy30 and their blends as stationary phases. Moreover, some thermodynamic properties of PVPhMMA50 and PS4VPy30 such as the weight fraction coefficient activity and the solubility parameters of both components (δ2) were also calculated at infinite dilution. Both the obtained specific retention volume values with the different polymer blends and the calculated polymer‐polymer interaction parameters ($\chi _{23} $) allowed us to conclude that the binary blends of two polymers are miscible in all proportion. These results are in good agreement with the phase behaviour observed by DSC.
The Effect of Extrusion Reprocessing on Structure and Properties of Isotactic Poly(propylene)
Authors: Oikonomidou O. , Triantou M. I. , Tarantili P. A. , Anatolaki C. , Karnavos N.
Published: December 2012

Summary: In this study, isotactic poly(propylene) (PP) and its nanocomposites reinforced with organic modified montmorillonite (OMMT) were subjected to five subsequent extrusion cycles, in order to simulate the effect of the processing involved with mechanical recycling on their properties. Additionally, tests were run in an attempt to explore whether the reprocessed polymers are appropriate as raw materials for several applications. It was concluded that repeated processing does not significantly affect the rheological and thermal properties, as well as the thermal stability of the above studied materials. Regarding mechanical properties, the tensile and flexural strength of the examined products remain almost unaffected. PP samples presented a decrease in tensile and flexural moduli, whereas in the case of OMMT/PP nanocomposites reprocessing improves these properties, probably due to better intercalation of clay platelets taking place upon melt mixing.
Droplet Breakup Theory as a Method to Predict the Processing Conditions of Polymer Blends
Authors: Hoang V. N.
Published: December 2012

Sumary: The droplet breakup theory has been investigated in predicting processing conditions of polymer blends. A ternary blend of polystyrene/styrene‐butadiene rubber/natural rubber (PS/SBR/NR) was used with a constant content of every component [PS/SBR/NR 80/(30/70) wt.%] while changing mixing temperature, time and rotor speed. The experimental design was applied to optimize mixing conditions where izod impact and tensile strength were the targets. The mixing conditions from theory calculation: 190 °C, 56.5 rpm, 3.47 ÷ 5.47 min. Suitable blending conditions resulting in the experiments were: 190 °C, 60 rpm, 5.44 min.
Tendency to Network of Small and Medium‐sized Enterprises: Combining Organizational Economics and Resource‐based Perspectives
Authors: Meiseberg Brinja , Ehrmann Thomas
Published: December 2012

Small and medium‐sized enterprises (SMEs) face critical challenges in implementing collaborative strategies, including the difficulty of finding partners, the strain on managerial resources, and the risk of exploitation by larger partner firms. However, little is known about tendencies to network in SMEs. This paper builds on organizational economics and the resource‐based perspectives. Survey data from 348 German SMEs reveal that predictions from both theories play a role for the tendencies of SMEs to network, yet organizational capabilities in terms of coordination and communication and bonding in alliances are most relevant for cooperation decisions. We provide managerial implications for cooperation involving SMEs. Copyright © 2012 John Wiley & Sons, Ltd.
Assembling and Manipulating with Light
Authors: Ostendorf Andreas , Ksouri Sarah Isabelle , Aumann Andreas , Ghadiri Reza
Published: December 2012

Laser assemblers offer a new processing technique to fabricate complex 3D‐microstructures. Based on Holographic Optical Tweezers (HOT) spherical microparticles can be manipulated with highest flexibility and precision. Using a Spatial Light Modulator (SLM) the incident laser beam is rearranged into flexible light patterns in order to generate multiple spots which can be modified with a frame rate of several tens of Hertz. Additionally, non‐spherical particles manufactured e.g. by a 2‐photon‐polymerization (2PP) process can be utilized to realize more complex building blocks. A combination of contactless manufacturing by 2PP and manipulation by HOT provides the possibility of analyzing generated 2PP‐structures on its manipulative performances as well as the assembling of the 2PP‐preforms.
Human fetal sacrococcygeal extension or ‘tail’ in the second trimester: prenatal diagnosis, associated findings, and clinical outcome
Authors: Dobson Lori J. , Barnewolt Carol E. , Morash Donna , Connolly Susan A. , Estroff Judy A.
Published: December 2012

Background

There are over 30 cases of prenatally diagnosed sacral extensions or human ‘tails’ in the literature, including isolated and syndromic etiologies. Most cases were reported to resolve by the second trimester and postnatal course was benign. Our objective was to describe the prenatal findings, associated anomalies, and clinical outcome of a series of seven fetuses diagnosed prenatally with fetal sacrococcygeal extension.

Methods

In a prospective study on a series of 4040 consecutive patients seen through our clinic in a 10‐year period, 7 patients had a sacrococcygeal extension identified on fetal imaging. Fetal sonographic and magnetic resonance imaging findings, results of genetic testing, and clinical outcomes were analyzed.

Results

All seven fetuses had associated anomalies, including neurologic, craniofacial, cardiac, spinal, renal, and musculoskeletal abnormalities, or abnormal ultrasound findings including growth restriction and abnormal umbilical cord Doppler. There were two cases of trisomy 13 and one case of Pfeiffer syndrome. The mean gestational age at diagnosis was 19.3 weeks.

Conclusion

When a sacrococcygeal extension is seen on fetal imaging, work‐up should include detailed fetal imaging and karyotype, and fetal growth should be monitored. Our experience with fetal sacrococcygeal extension demonstrates variability in the underlying presentation and etiology, making counseling in a prenatal setting challenging. © 2012 John Wiley & Sons, Ltd.
High energy density nanocomposites based on poly(vinylidene fluoride‐chlorotrifluoroethylene) and barium titanate
Authors: Wen Fei , Xu Zhuo , Xia Weimin , Wei Xiaoyong , Zhang Zhicheng
Published: December 2012

Three series of poly (vinylidene fluoride‐chlorotrifluoroethylene)/barium titanate (BT) nanocomposites with varied compositions were fabricated via solution cast process followed by thermally treated in different ways. Quenching the composite samples at lower temperature could effectively enhance their dielectric constant, breakdown strength as well as the energy density. The highest energy density (13.6 J/cm3) is observed in the sample quenched from 200°C to −94°C with 5 vol% BT, which is much higher than nanocomposites reported in the current literature. The addition of ceramic particles leads to the improvement of dielectric permittivity and energy density measured under the same electric field. However, the dielectric breakdown strength and the energy density measured at breakdown strength of the resultant composites are reduced as a function of BT content. The fixed maximum electric displacement and reduction of saturation electric field suggest that the addition of ceramic particles with high dielectric constant may help increase the energy density of composites under low electric field but not for high electric field. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers.
Quantification of local geometry and local symmetry in models of disordered materials
Authors: Cliffe Matthew J. , Goodwin Andrew L.
Published: December 2012

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We suggest two metrics for assessing the quality of atomistic configurations of disordered materials, both of which are based on quantifying the orientational distribution of neighbours around each atom in the configuration. The first metric is that of geometric invariance: i.e., the extent to which the neighbour arrangements are as similar as possible for different atoms, allowing for variations in frame of reference. The second metric concerns the degree of local symmetry. We propose that for a set of configurations with equivalent pair correlations, ranking highly those configurations with low geometric invariance but with high local symmetry selects for structural simplicity in a way that does not rely on formal group theoretical language (and hence long‐range periodic order). We show that these metrics rank a range of SiO2 and a‐Si configurations in an intuitive manner, and are also significantly more sensitive to unphysical features of those configurations in a way that metrics based on pair correlations are not. We also report that implementation of the metrics within a reverse Monte Carlo (RMC) algorithm gives rise to an energy landscape that is too coarse (at least in this initial implementation) for amorphous structure ‘solution’.
Surface‐related defects of ZnO micro and nano crystals prepared by sol‐gel technique
Authors: Greulich‐Weber Siegmund , Azam Syed Jahanzeb , Brodehl Christoph , Baumgarten Tim
Published: December 2012

Nano and micro crystalline ZnO were synthesized by two different sol‐gel routes. The nominally undoped ZnO crystals were investigated by X‐ray diffraction, electron paramagnetic resonance (EPR), photoluminescence (PL) and electron microscopy. These measurements are discussed together with surface and volume conductivity measured. Two intrinsic defects were observed having g factors close to that of the shallow donor in ZnO. A further defect was correlated with the conductivity of ZnO nanocrystals and is shown to be due to a surface‐related defect. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Delayed recombination and excited state ionization of the Ce3+ activator in the SrHfO3 host
Authors: Mihóková Eva , Jarý Vítězslav , Schulman Lawrence S. , Nikl Martin
Published: December 2012

We determine the thermal ionization energy of the excited state of Ce3+ in a SrHfO3 host by a contactless optical method based on the measurement and analysis of delayed recombination decay following UV excitation. We show the applicability of the method for microcrystalline powder samples. The method provides a consistent value of thermal ionization energy of about 0.25 eV, as previously determined by a ther‐ mally stimulated luminescence (TSL) study after UV illumination. We reveal a low temperature contribution to the delayed recombination signal and address its origin. This contribution indicates a complex interaction of the luminescence center with the host lattice neighborhood and the presence of temperature independent losses of fast scintillation light. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improving transient performance for output regulation problem of linear systems with input saturation
Authors: Zhang Bo , Lan Weiyao
Published: December 2012

This paper addresses the transient performance of output regulation problem for general linear system with input saturation. To improve the transient performance, the composite nonlinear feedback (CNF) control technique is introduced to solve the output regulation problem. On the basis of the linear feedback control law that solves the output regulation problem, a state feedback CNF control law and an output feedback with feedforward CNF control law are constructed, respectively. The CNF control law consists of a linear feedback part and a nonlinear feedback part. Introducing the nonlinear feedback part does not change the solvability condition of the output regulation problem, but the transient performance can be improved significantly by appropriately choosing the linear feedback gain and the nonlinear feedback gain in the CNF control law. The effectiveness of the CNF control is illustrated by a disturbance rejection problem.Copyright © 2012 John Wiley & Sons, Ltd.
Tom Ten Have's contributions to causal inference and biostatistics: review and future research directions
Authors: Small Dylan S. , Joffe Marshall M. , Lynch Kevin G. , Roy Jason A. , Russell Localio A.
Published: December 2012

Tom Ten Have made many contributions to causal inference and biostatistics before his untimely death. This paper reviews Tom's contributions and discusses potential related future research directions. We focus on Tom's contributions to longitudinal/repeated measures categorical data analysis and particularly his contributions to causal inference. Tom's work on causal inference was primarily in the areas of estimating the effect of receiving treatment in randomized trials with nonadherence and mediation analysis. A related area to mediation analysis he was working on at the time of his death was posttreatment effect modification with applications to designing adaptive treatment strategies. Copyright © 2012 John Wiley & Sons, Ltd.
Short and Long Term, In Vitro and In Vivo Correlations of Cellular and Tissue Responses to Mesoporous Silicon Nanovectors
Authors: Martinez Jonathan O. , Boada Christian , Yazdi Iman K. , Evangelopoulos Michael , Brown Brandon S. , Liu Xuewu , Ferrari Mauro , Tasciotti Ennio
Published: December 2012

The characterization of nanomaterials and their influence on and interactions with the biology of cells and tissues are still partially unknown. Multistage nanovectors based on mesoporous silicon have been extensively studied for drug delivery, thermal heating, and improved diagnostic imaging. Here, the short‐ and long‐term changes occurring in human cells upon the internalization of mesoporous silicon nanovectors (MSV) are analyzed. Using qualitative and quantitative techniques as well as in vitro and in vivo biochemical, cellular, and functional assays, it is demonstrated that MSV do not cause any significant acute or chronic effects on cells and tissues. In vitro cell toxicity and viability are analyzed, as well as the maintenance of cell phase cycling and the architecture upon the internalization of MSV. In addition, it is evaluated whether MSV produce any pro‐inflammatory responses and its biocompatibility in vivo is studied. The biodistribution of MSV is followed using longitudinal in vivo imaging and organ accumulation is assessed using quantitative elemental and fluorescent techniques. Finally, a thorough pathological analysis of collected tissues demonstrates a mild transient systemic response in the liver that dissipates upon the clearance of particles. It is proposed that future endeavors aimed at understanding the toxicology of naked drug carriers should be designed to address their impact using in vitro and in vivo short‐ and long‐term evaluations of systemic response.
Microstructure and Mechanical Properties of a Low Carbon Bainitic Steel
Authors: Lan Hui Fang , Du Lin Xiu , Liu Xiang Hua
Published: December 2012

A low carbon bainitic steel with microstructure of granular bainite (GB), acicular ferrite (AF), and bainitic ferrite (BF) is obtained under different deformation and cooling rate. The effect of deformation and cooling rate on microstructural characteristics such as the type of the matrix, the size, and area fraction of the martensite–austenite (M–A) constituents is investigated. In addition, the nanohardness of these three kinds of matrix as well as that of the M–A constituents in them is characterized. Further, the effect of matrix and M–A constituents on strength–toughness balance is studied. Results indicate that deformation expands the transformation region. The size as well as the area fraction of the M–A constituent decreases with the increasing of the cooling rate. After deformation, the area fraction of the M–A constituents increases. Nanohardness of GB, AF, and BF increases orderly, but that of the M–A constituents in them decreases accordingly. The nanohardness of the M–A constituent is significantly affected by its carbon concentration. AF is the optimum microstructure having superior strength–toughness balance.
Study on Isothermal Precipitation Behavior of Nano‐Scale (Nb,Ti)C in Ferrite/Bainite in 780 MPa Grade Ultra‐High Strength Steel
Authors: Wang Xiaonan , Zhao Yanfeng , Liang Bingjie , Du Linxiu , Di Hongshuang
Published: December 2012

In order to precisely control the nano‐scale (Nb,Ti)C precipitate in hot‐rolled 780 MPa Nb–Ti microalloying C–Mn steel, isothermal precipitation behavior of nano‐scale (Nb,Ti)C precipitate in the ultra‐high strength steel was investigated by the thermal simulation experiments. The results indicated that defects of deformed supercooled austenite became the preferential nucleation sites of nano‐scale (Nb,Ti)C precipitate and ferrite, so there was a competition mechanism for austenitic defects between ferritic transformation and precipitate nucleation. Bainitic transformation could effectively freeze austenitic defects, and additional defects are formed because of volume expansion in bainitic transformation process, so bainitic transformation could promote precipitate nucleation. However, precipitate was impacted by both nucleation driving force and atom diffusibility, so the peak temperature of nano‐scale (Nb,Ti)C precipitate was 550°C. On the basis of the above theoretical results, hot rolling experiments results showed that when the coiling temperature was 550°C, the yield strength and tensile strength were 710 and 790 MPa, respectively, and the microstructure of hot‐rolled steels was mainly bainitic ferrite, and a large number of <10 nm nano‐scale (Nb,Ti)C precipitates were obtained. Precipitation strengthening contribution to reached 325 MPa.
Leadership Pedagogy: Putting Theory to Practice
Authors: Rosch David M. , Anthony Michael D.
Published: December 2012

This chapter will discuss the foundations of effective pedagogy and content, and how to apply these to leadership education. International Leadership Association overarching Content Guiding Question: “What is the content of the leadership education program and how was it derived?”
A comprehensive environmental assessment approach to engineered nanomaterials
Authors: Davis J. Michael
Published: December 2012

The anticipated benefits of engineered nanomaterials (ENMs) should be weighed against their possible negative impacts. Comprehensive environmental assessment (CEA) provides a means of evaluating such trade‐offs in a holistic and systematic manner. CEA consists of both a framework for organizing information and a process for using collective judgment to identify and prioritize the issues presented by ENMs. As a meta‐assessment approach, CEA is designed to assist both research planners and risk managers by building on various assessment and analytic tools used by risk assessors. Given the immature state of the science for ENMs, CEA is currently being primarily used for prioritizing research directions. Therefore, highlights of case studies of selected ENM applications are presented to illustrate how CEA has been applied thus far to help guide research efforts to support future assessment efforts. In addition, CEA is discussed in relation to topical subjects, such as sustainability, transparency, and stakeholder engagement. Finally, comparisons to other life cycle‐based assessment approaches directed at ENMs are noted. WIREs Nanomed Nanobiotechnol 2013, 5:139–149. doi: 10.1002/wnan.1203

This article is categorized under:

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology

Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine

Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials
Alkali Metal and Organo Group‐14 Element Ferrocenecarbo­selenoates: Synthesis and Structures
Authors: Takahashi Toshinori , Niyomura Osamu , Kato Shinzi , Ebihara Masahiro
Published: December 2012

Lithium, sodium, and potassium ferrocenecarboselenoates were synthesized in good yields by the reaction of ferrocenoyl chloride with the corresponding metal selenides. In air, the saltsquickly oxidized to give diferrocenoyl diselenide. The salts readily reacted with alkyl and organo‐germanium, ‐tin and ‐lead halides to give the corresponding Se‐alkyl and Se‐organo Group‐14 element ferrocenecarboselenoates [(FcCOSe)xMPh4–x (M = Ge, Sn, Pb; x = 1–3) in moderate to good yields. In contrast, the reaction of the sodium and potassium salts with trimethylsilyl chloride led to O‐trimethylsilyl ferrocenecarboselenoate FcCSeOSiMe3. Treatment of the O‐silyl ester with RbF and CsF led to rubidium and cesium ferrocenecarboselenoates, respectively, in good yields. The structures of FcCOSetBu, (FcCOSe)2SnPh2, and FcCOSePbPh3 were revealed by X‐ray molecular structure analysis.
Maternal and fetal tyrosinemia type I
Authors: Garcia Segarra N. , Roche S. , Imbard A. , Benoist J. F. , Grenèche M. O. , Davit‐Spraul A. , Ogier de Baulny H.
Published: December 2012

A 22 year‐old woman with tyrosinemia type I (HT1) married her first cousin who is heterozygous for the same FAH mutation for which the patient is homozygous. During her pregnancy she was treated with diet (prescribed tyrosine intake 300 mg/day), and nitisinone (60 mg/day). Median plasma tyrosine levels were 560 μmol/L (range: 375–838, n = 21) and nitisinone 51 μmol/L (range: 41–57, n = 3) during pregnancy. She gave birth to a clinically healthy girl affected with tyrosinemia type 1. Birth was normal (birth weight 2615 g) and the baby had normal liver function, normal plasma alpha‐fetoprotein concentrations, low urinary excretion of phenolic acids and no detectable succinylacetone. At birth, the baby had hypertyrosinemia (860 μmol/L in blood cord) and nitisinone levels of 14 μmol/L. Following molecular confirmation of the diagnosis of HT1 specific treatment began on day 15 by which time she had detectable urinary succinylacetone.
Uptake and translocation of organophosphates and other emerging contaminants in food and forage crops
Authors: Eggen Trine , Heimstad Eldbjørg S. , Stuanes Arne O. , Norli Hans Ragnar
Published: December 2012

Emerging contaminants in wastewater and sewage sludge spread on agricultural soil can be transferred to the human food web directly by uptake into food crops or indirectly following uptake into forage crops. This study determined uptake and translocation of the organophosphates tris(1-chloro-2-propyl) phosphate (TCPP) (log K
ow 2.59), triethyl-chloro-phosphate (TCEP) (log K
ow 1.44), tributyl phosphate (TBP) (log K
ow 4.0), the insect repellent N,N-diethyl toluamide (DEET) (log K
ow 2.18) and the plasticiser N-butyl benzenesulfonamide (NBBS) (log K
ow 2.31) in barley, wheat, oilseed rape, meadow fescue and four cultivars of carrot. All species were grown in pots of agricultural soil, freshly amended contaminants in the range of 0.6–1.0 mg/kg dry weight, in the greenhouse. The bioconcentration factors for root (RCF), leaf (LCF) and seed (SCF) were calculated as plant concentration in root, leaf or seed over measured initial soil concentration, both in dry weight. The chlorinated flame retardants (TCEP and TCPP) displayed the highest bioconcentration factors for leaf and seed but did not show the same pattern for all crop species tested. For TCEP, which has been phased out due to toxicity but is still found in sewage sludge and wastewater, LCF was 3.9 in meadow fescue and 42.3 in carrot. For TCPP, which has replaced TCEP in many products and also occurs in higher residual levels in sewage sludge and wastewater, LCF was high for meadow fescue and carrot (25.9 and 17.5, respectively). For the four cultivars of carrot tested, the RCF range for TCPP and TCEP was 10–20 and 1.7–4.6, respectively. TCPP was detected in all three types of seeds tested (SCF, 0.015–0.110). Despite that DEET and NBBS have log K
ow in same range as TCPP and TCEP, generally lower bioconcentration factors were measured. Based on the high translocation of TCPP and TCEP to leaves, especially TCPP, into meadow fescue (a forage crop for livestock animals), ongoing risk assessments should be conducted to investigate the potential effects of these compounds in the food web.
The Patient's Perspective on Carpal Tunnel Surgery Related to the Type of Anesthesia: A Prospective Cohort Study
Authors: Davison Peter G. , Cobb Tyson , Lalonde Donald H.
Published: December 2012

Background

The purpose of this study was to provide prospective independently analyzed evidence on how patients feel about a carpal tunnel release (CTR) performed under local anesthesia only (no sedation or tourniquet) versus with local anesthesia, intravenous (IV) sedation, and a tourniquet.

Methods

This prospective cohort study compared 100 consecutive CTRs done with only lidocaine and epinephrine in Saint John, New Brunswick to 100 consecutive CTRs done with IV sedation in Davenport, Iowa. Patient perspectives on the anesthesia were captured in a blinded questionnaire 1 week postoperatively.

Results

For subsequent surgery, 93 % of wide awake patients would choose local anesthesia only and 93 % of sedated patients would choose sedation. Wide awake patients spent less time at the hospital ( M=2.6 h) than sedated patients ( M=4.0 h; p<.001). Preoperative blood work, electrocardiograms, and/or chest radiographs were done for 3 % of wide awake patients and 48 % of sedated patients ( p<0.001). Preoperative anxiety levels for wide awake patients were lower than for sedated patients ( p=0.007); postoperative anxiety was similar. There were no anesthesia complications in either group. Narcotics were used by 5 % of unsedated patients and 67 % of sedated patients ( p<0.001). Adequate pain control was reported by 89 % and 90 % of patients, respectively.

Conclusions

The majority of patients from both cohorts liked whichever method of anesthesia they received and would choose it again. However, sedated patients spent more time at the hospital, required more preoperative testing, and reported greater preoperative anxiety.
Equality, Justice and Identity in an Expatriate/Local Setting: Which Human Factors Enable Empowerment of Filipino Aid Workers?
Authors: Smith Nigel Vaughan
Published: December 2012

This study explored which of social dominance, social identity and perceptions of organisational justice were most predictive of self-reported empowerment among aid workers in the Philippines ( N = 98). Responses to an online survey available in English and Tagalog were obtained from employees of diverse locally operating aid organisations in the Philippines. The survey included composite measures of empowerment, perceived social dominance, social identity and organisational justice. All measures except perceived social dominance performed as theorised in the Philippine context of this study. The best predictor of empowerment was the aspect of organisational justice centering on the fairness of personal interactions (interactional justice; β = .331). An interaction effect between interactional justice and aspects of empowerment and social (Filipino) identity was also observed (β = .233), implying that a secure Filipino identity may act as a buffer to consequences of injustice, all other things being equal. The overall pattern of results suggests that justice plays a more significant role than either social dominance or identity in contributing to empowerment amongst Filipino aid employees. Strikingly, interactional justice may matter more than distributive justice.
Applying stock indicators for assessment of a recreational surf clam (Donax deltoides) fishery in Victoria, Australia
Authors: Lewis Zac , Giri Khageswor , Versace Vincent L. , Scarpaci Carol
Published: December 2012

The aim of this study was to apply indicators for monitoring the impacts of harvest in a recreational surf clam fishery. We investigated trends in abundance, biomass and size structure and proportion of sexual maturity for the pipi (Donax deltoides) in Venus Bay, Australia. The surf clam stock was sampled during the peak harvesting season in the Australian summer (November to February) at four sites exposed to varying degrees of recreational harvest. Sampling was based on three transects at each site; with 0.027 m3 (0.3 m × 0.3 m × 0.3 m) quadrats stratified within transects by tidal position. Restricted maximum likelihood mixed model analyses were used to examine fixed effect combinations after including a priori random effect for transect within site. Results demonstrated that relative abundance varied significantly (P = 0.0090) among sampling months but not among sites. Relative abundance declined across the peak summer harvest season. The proportion of maturity varied significantly (P = 0.00026) among sites whereas relative biomass varied significantly (P = 0.0043) among months by sites. Relative biomass and the proportion of maturity were considerably higher at the site exposed to minimal harvest compared to other sites. This study demonstrates that a suite of indictors including biomass, size–frequency and proportion of maturity are likely to provide a more accurate assessment of stock status in recreationally fished surf clam populations, than relative abundance. This highlights the need to develop methods to estimate relative biomass in surf clam populations that are not exploited commercially.
THE YALAHAU REGION: A STUDY OF ANCIENT MAYA SOCIOPOLITICAL ORGANIZATION
Authors: Glover Jeffrey B.
Published: December 2012

The Yalahau Regional Settlement Pattern Survey (YRSPS) addresses the complex negotiations that constituted ancient Maya society through an investigation of the distribution of settlement across the Yalahau region of northern Quintana Roo, Mexico. This paper begins with a brief culture-historical background of the Yalahau region where occupation ranges from the Middle Preclassic period (700–200b.c.) to the Postclassic period (a.d.1100–1521). The region had its peak occupation during the Terminal Preclassic period (75b.c./a.d.100–a.d.400), and this paper explores how monumental architecture, through its size and the rituals conducted in and around it, materialized an enduring sense of community identity during this time period. In so doing, this paper examines the tensions within and between communities as sociopolitical strategies are negotiated and contested in the continually messy process of constituting society.
SOIL GEOCHEMICAL ANALYSES AT THE PRECLASSIC SITE OF XTOBO, YUCATAN, MEXICO
Authors: Anderson David S. , Bair Daniel A. , Terry Richard E.
Published: December 2012

The geochemical analysis of soil samples collected in association with archaeological remains has proven to be an effective tool in the identification of past human behaviors. These methodologies are here applied to the study of notable features from the site of Xtobo, Yucatan, Mexico. Xtobo is a Preclassic Maya regional center in northwest Yucatan exhibiting a complex settlement pattern, including a well-defined plaza, multiple raised causeways, and a ballcourt. In addition, the site includes a large defined open area, which was initially thought to be a potential marketplace. The results of the geochemical soil analyses identified several areas of food production and consumption throughout the site, along with potential craft production zones. The results in association with the potential marketplace were intriguing, but inconclusive.
LAS ETAPAS MÁS TEMPRANAS DE LA ALFARERÍA MAYA EN EL NOROESTE DE LA PENÍNSULA DE YUCATAN
Authors: Gallareta Teresa Ceballos , Castellanos Fernando Robles
Published: December 2012

Excavaciones de salvamento arqueológico en varios sitios aledaños a la ciudad de Mérida han aportado nueva información sobre las características y la ubicación cronológica de las etapas más antiguas de la alfarería maya del noroeste de Yucatan. Un reciente cotejo de previas y nuevas evidencias estratigráficas y la calibración 1–2 sigma de 16 fechas de 14C provenientes de contextos preclásicos, nos sugiere que la producción del repertorio cerámico Nabanche temprano, el más antiguo hallado hasta ahora en el norte de Yucatan, comenzó en una fecha anterior al año 1000 a.C. Después del año 400 a.C. la alfarería Nabanche temprano empezó a ser reemplazada paulatinamente por nuevos grupos cerámicos, principalmente por el Xanaba rojo, hasta su virtual desaparición al inicio de la era cristiana.
Multiple mechanisms mediate enhanced immunity generated by mAb‐inactivated F. tularensis immunogen
Authors: Iglesias Bibiana V , Bitsaktsis Constantine , Pham Giang , Drake James R , Hazlett Karsten R O , Porter Kristen , Gosselin Edmund J
Published: December 2012

We have previously demonstrated that immunization with the inactivated Francisella tularensis, a Category A intracellular mucosal pathogen, combined with IgG2a anti‐F. tularensis monoclonal antibody (Ab), enhances protection against subsequent F. tularensis challenge. To understand the mechanism(s) involved, we examined the binding, internalization, presentation, and in vivo trafficking of inactivated F. tularensis in the presence and absence of opsonizing monoclonal Ab. We found that when inactivated F. tularensis is combined with anti‐F. tularensis monoclonal Ab, presentation to F. tularensis‐specific T cells is enhanced. This enhancement is Fc receptor (FcR)‐dependent, and requires a physical linkage between the monoclonal Ab and the inactivated F. tularensis immunogen. This enhanced presentation is due, in part, to enhanced binding and internalization of inactivated F. tularensis by antigen(Ag)‐presenting cells, and involves interactions with multiple FcR types. Furthermore, targeting inactivated F. tularensis to FcRs enhances dendritic cell maturation and extends the time period over which Ag‐presenting cells stimulate T cells. In vivo trafficking studies reveal enhanced transport of inactivated F. tularensis immunogen to the nasal‐associated lymphoid tissue in the presence of monoclonal Ab, which is FcRn‐dependent. In summary, these are the first comprehensive studies using a single‐vaccine protection model/immunogen to establish the array of mechanisms involved in enhanced immunity/protection mediated by an FcR‐targeted mucosal immunogen. These results demonstrate that multiple cellular/immune mechanisms contribute to FcR‐enhanced immunity.
Effects of relative emergence time and water deficit on the timing of fruit dispersal in Raphanus raphanistrum L.
Authors: Taghizadeh M. S. , Nicolas M. E. , Cousens R. D.
Published: December 2012

Seed dispersal is both a spatial and a temporal phenomenon, although most studies focus on spatial aspects. Seed initiation on the maternal plant may occur over a considerable period, especially in indeterminately flowering species, and thus seeds may be exposed to a wide range of environmental conditions during their development. The result is variation in the timing of seed development, the anatomy of structures related to the dispersal process, and the behaviour and fate of seeds post-dispersal. A key resource during the growth and development of summer-maturing species in most areas, and one that is thus likely to modify these processes, is water. Two experiments were therefore undertaken to describe (i) the development of Raphanus raphanistrum fruits and the timing of fruit dispersal, and (ii) the effects of water availability on the timing of fruit dispersal. Fewer seeds were produced and subsequently dispersed by later emerging plants. The duration of fruit dispersal became shorter when the plants emerged progressively later than the crop, and the time of maximum dispersal was later. For cohorts of fruits initiated at the same time, those that developed under mild and severe water deficit reached their final length sooner, and were dispersed sooner, than those receiving a plentiful supply of water. Thus, the phenology of the maternal plant and the nature of its environment can modify the timing of propagule maturity and consequently dispersal. Such information may provide an opportunity for managers to reduce weed seed return to their field or, conversely, to regulate the amount of contaminated grain or reduce dispersal to other locations.
Molecular mapping and validation of Rlm1 gene for resistance to Leptosphaeria maculans in canola (Brassica napus L.)
Authors: Raman Rosy , Taylor Belinda , Lindbeck Kurt , Coombes Neil , Barbulescu Denise , Salisbury Phil , Raman Harsh
Published: December 2012

European winter canola (Brassica napus L.) cultivars harbour genes for durable resistance to the fungus Leptosphaeria maculans, which causes blackleg disease under Australian environmental conditions. Previous studies have shown that resistance in winter-type cultivars Maxol and Columbus is controlled by two genes, Rlm1 and Rlm3, which have been mapped using randomly amplified polymorphic DNA markers onto chromosome A7. We mapped a doubled-haploid population that consisted of 101 lines from a cross between Maxol*1 and Westar-10 using diversity arrays technology and simple sequence repeat (SSR)-based markers. Two SSR marker loci, Xol12-e03 and Xra2-a05b, flanked the Rlm1 locus at an interval of 6.7 cM, which corresponds to ~3.2 Mb of the Brassica rapa genomic sequence; this region contains several genes encoding putative kinase and leucine-rich repeat-type disease-resistance proteins. SSR markers were further tested for their linkage with the Rlm1 locus in an independent population derived from Columbus*3/Westar-10. Our results showed that SSR markers linked to Rlm1 can be useful for monitoring Rlm1 gene introgression in breeding populations derived from Maxol and Columbus.
Molecular identification supports most traditional morphological species of Ruspolia (Orthoptera : Conocephalinae)
Authors: Zhou Zhi Jun , Li Rui Lian , Huang Da Wei , Shi Fu Ming
Published: December 2012

Molecular identification systems depend on genetic diversity based on a short mitochondrial DNA fragment being markedly lower within than between species to infer identification of specimens. Our analyses show that both COI and CytB fragments can successfully distinguish most Ruspolia species. R. jezoensis was synonymised with R. dubia, and R. liangshanensis may be recently separated from R. dubia. R. indica, often called Euconocephalus indicus, occupied a well supported position within Ruspolia, and should be transferred into Ruspolia. The individuals of R. lineosa from Yunnan formed a monophyletic group at the base of the R. lineosa clade, and the Kimura 2-parameter distance between it and other R. lineosa individuals was 0.065 for COI and 0.069 for CytB, which may be the result of isolated or remote populations. However, for recently diverged taxa R. liangshanensis and R. dubia, straightforward application of barcoding rules may prove problematic without morphological, behavioural or ecological data.