bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification of polyethylene wax in semibatch laboratory reactor and a study of different parameters on wax production as a by‐product in the slurry ethylene polymerization
Authors: Bayat Mohammad Hossein , Abdouss Majid , Javanbakht Mehran
Published: May 2012

In coordination polymerization of alpha‐olefins utilizing Ziegler‐Natta catalysts via slurry, polyolefin is produced with other by‐products such as polyethylene wax. Wax is defined as a linear short chain saturated by hydrocarbons in the relevant industries. Hexane and heptane are two of the most common suspending agents for the slurry process and wax molecules are soluble or swollen in these kinds of liquids. After termination of polymerization, wax separates from the main product by physical processes. A procedure for wax quantification in a laboratory reactor is suggested. Also, impacts of various factors such as reaction duration, pressure, and cocatalyst on wax generation have been investigated. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Short polyaniline nanorod prepared in the presence of para‐phenylenediamine
Authors: Chao Liang , Ho Ko‐Shan , Shen Sheng‐Yen , Pu Hsin‐Yu , Hsieh Tar‐Hwa , Kuo Chung‐Wen , Tseng Bo‐Hao
Published: May 2012

para‐Phenylenediamines (pPDAs) were mixed with aniline to synthesize a low molecular weight, nanowired polyaniline via emulsion polymerization, which demonstrated smaller intrinsic viscosity. Fourier transform infrared‐spectra illustrated the presence of phenazines in the polymers in the presence of pPDA. Free carrier‐tails in UV‐Vis‐NIR spectra are still present but their numbers decreased with pPDAs. Scanning electronic microscopy and transmission electronic microscopy (TEM) images showed the neat PANINTs shrank significantly and became randomly distributed after dedoping but the diameters of the PANINT‐pPDAs decreased slightly. TEM micrographs demonstrated the hollow morphology for the neat PANINTs but that of PANINT‐pPDA was shorter, solid nanowires. X‐ray diffractions patterns illustrated a layered structure for neat PANINTs which own a long c‐axis, not found for PANINT‐pPDAs. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Biolignin™ based epoxy resins
Authors: Delmas Guo‐Hua , Benjelloun‐Mlayah Bouchra , Bigot Yves Le , Delmas Michel
Published: May 2012

Wheat straw Biolignin™ was used as a substitute of bisphenol‐A in epoxy resin. Synthesis was carried out in alkaline aqueous media using polyethyleneglycol diglycidyl ether (PEGDGE) as epoxide agent. Structural study of Biolignin™ and PEGDGE was performed by solid‐state 13C NMR and gel permeation chromatography, respectively, before epoxy resin synthesis. Biolignin™ based epoxy resins were obtained with different ratios of Biolignin™ : PEGDGE and their structures were analyzed by solid‐state 13C NMR. The crosslinking of PEGDGE with Biolignin™ was highlighted in this study. Properties of Biolignin™ based epoxy resins were analyzed by differential scanning calorimetry and dynamic load thermomechanical analysis as well as compared with those of a bisphenol‐A epoxy‐amine resin. Depending on the epoxy resin formulation, results confirmed the high potential of Biolignin™ as a biosourced polyphenol used in epoxy resin applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Fabrication and characterization of poly(vinyl alcohol)/graphene oxide nanofibrous biocomposite scaffolds
Authors: Qi Y. Y. , Tai Z. X. , Sun D. F. , Chen J. T. , Ma H. B. , Yan X. B. , Liu B. , Xue Q. J.
Published: May 2012

Nanofibrous biocomposite scaffolds of poly(vinyl alcohol) (PVA) and graphene oxide (GO) were prepared by using electrospinning method. The microstructure, crystallinity, and morphology of the scaffolds were characterized through X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The mechanical properties were investigated by tensile testing. Moreover, Mouse Osteoblastic Cells (MC3T3‐E1) attachment and proliferation on the nanofibrous scaffolds were investigated by MTT [3‐(4,5‐dimeth‐ylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide] assay, SEM observation and fluorescence staining. XRD and FTIR results verify the presence of GO in the scaffolds. SEM images show the three‐dimensional porous fibrous morphology, and the average diameter of the composite fibers decreases with increasing the content of GO. The mechanical properties of the scaffolds are altered by changing the content of GO as well. The tensile strength and elasticity modulus increase when the content of GO is lower than 1 wt %, but decrease when GO is up to 3 and 5 wt %. MC3T3‐E1 cells attach and grow on the surfaces of the scaffolds, and the adding of GO do not affect the cells' viability. Also, MC3T3‐E1 cells are likely to spread on the PVA/GO composite scaffolds. Above all, these unique features of the PVA/GO nanofibrous scaffolds prepared by electrospinning would open up a wide variety of future applications in bone tissue engineering and drug delivery systems. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Quantized Consensus of Multi‐Agent Systems Via Broadcast Gossip Algorithms
Authors: Liu Zhi‐Wei , Guan Zhi‐Hong , Li Tao , Zhang Xian‐He , Xiao Jiang‐Wen
Published: May 2012

Distributed consensus problems of multi‐agent systems on directed networks are studied in this paper. For the communication of agents, it is assumed that only one agent can be selected with a prescribed probability, and it broadcasts its own state to neighbors via quantized communication (for any arbitrary quantization) at each time step. For this kind of communication, the fundamental questions are how to design distributed algorithms and what kinds of network topology together lead to the quantized consensus. A class of broadcast gossip algorithms is proposed, and a necessary and sufficient graphical condition is given to ensure the quantized consensus. In particular, the obtained graphical condition does not require a symmetric network topology, which is weaker than those in some other literature. Several numerical simulations are given to show the effectiveness of the proposed algorithms.
Substrate binding–dissociation and intermolecular electron transfer in cytochrome c oxidase are driven by energy‐dependent conformational changes in the enzyme and substrate
Authors: Ashe Damian , Alleyne Trevor , Sampson Valerie
Published: May 2012

Reduction of O2 by cytochrome c oxidase (COX) is critical to the cellular production of adenosine‐5′‐triphosphate; COX obtains the four electrons required for this process from ferrocytochrome c. The COX–cytochrome c enzyme–substrate complex is stabilized by electrostatic interactions via carboxylates on COX and lysines on cytochrome c. Conformational changes are believed to play a role in ferrocytochrome c oxidation and release and in rapid intramolecular transfer of electrons within COX, but the details are unclear. To gather specific information about the extent and relevance of conformational changes, we performed bioinformatics studies using the published structures of both proteins. For both proteins, we studied the surface accessibility and energy, as a function of the proteins' oxidation state. The residues of reduced cytochrome c showed greater surface accessibility and were at a higher energy than those of the oxidized cytochrome c. Also, most residues of the core subunits (I, II, and III) of COX showed low accessibility, ∼35%, and compared to the oxidized subunits, the reduced subunits had higher energies. We concluded that substrate binding and dissociation is modulated by specific redox‐dependent conformational changes. We further conclude that high energy and structural relaxation of reduced cytochrome c and core COX subunits drive their rapid electron transfer.
Molecular dynamic simulation studies on the effect of one residue chain staggering on the structure and stability of heterotrimeric collagen‐like peptides with interruption
Authors: Singam Ettayapuram Ramaprasad Azhagiya , Balamurugan Kanagasabai , Gopalakrishnan Ravimohan , Subramanian Sundar Raman , Subramanian Venkatesan , Ramasami Thirumalachari
Published: May 2012

A systematic molecular dynamics (MD) simulation has been carried out on collagen‐like peptides with different combinations of interruptions in the Gly–XAA–YAA repeats. Although experimental studies have been carried out to elucidate the structural consequences of homotrimeric collagen‐like peptides, this is the first report on the structural effect on the heterotrimeric models with G4G and G1G breaks present simultaneously in the constituent chains with difference in one residue chain staggering. The results reveal that the axial registry of the interrupted region changes significantly from that of conventional triple helical peptide without interruption. Further, results from MD simulations show the formation of a kink in the interrupted region of the triple‐helical peptides. The conformational analysis reveals that the interruption in the Gly–XAA–YAA pattern in these peptides induces β‐strand conformation in triple helical peptides. The conventional hydrogen bonds in the interrupted triad are affected and new nonconventional H‐bonds are formed in the triple helical structure, and as a result interrupted region becomes locally fragile. MM‐PBSA calculations on the different systems clearly suggest that the binding affinity varies marginally due to one residue staggering. However, it is found from the structural parameters that hydrogen‐bonding pattern differs significantly due to the difference in the staggering of chains. © 2012 Wiley Periodicals, Inc. Biopolymers 97:847–863, 2012.
Dissimilatory nitrate reduction by Pseudomonas alcaliphila with an electrode as the sole electron donor
Authors: Su Wentao , Zhang Lixia , Li Daping , Zhan Guoqiang , Qian Junwei , Tao Yong
Published: May 2012

Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were considered two alternative pathways of dissimilatory nitrate reduction. In this study, we firstly reported that both denitrification and DNRA occurred in Pseudomonas alcaliphila strain MBR with an electrode as the sole electron donor in a double chamber bio‐electrochemical system (BES). The initial concentration of nitrate appeared as a factor determining the type of nitrate reduction with electrode as the sole electron donor at the same potential (−500 mV). As the initial concentration of nitrate increased, the fraction of nitrate reduced through denitrification also increased. While nitrite (1.38 ± 0.04 mM) was used as electron acceptor instead of nitrate, the electrons recovery via DNRA and denitrification were 43.06 ± 1.02% and 50.51 ± 1.37%, respectively. The electrochemical activities and surface topography of the working electrode catalyzed by strain MBR were evaluated by cyclic voltammetry and scanning electron microscopy. The results suggested that cells of strain MBR were adhered to the electrode, playing the role of electron transfer media for nitrate and nitrite reduction. Thus, for the first time, the results that DNRA and denitrification occurred simultaneously were confirmed by powering the strain with electricity. The study further expanded the range of metabolic reactions and had potential value for the recognization of dissimilatory nitrate reduction in various ecosystems. Biotechnol. Bioeng. 2012; 109: 2904–2910. © 2012 Wiley Periodicals, Inc.
Targeted codon optimization improves translational fidelity for an Fc fusion protein
Authors: Hutterer Katariina M. , Zhang Zhongqi , Michaels Mark Leo , Belouski Ed , Hong Robert W. , Shah Bhavana , Berge Mark , Barkhordarian Hedieh , Le Eleanor , Smith Steve , Winters Dwight , Abroson Frank , Hecht Randy , Liu Jennifer
Published: May 2012

High levels of translational errors, both truncation and misincorporation in an Fc‐fusion protein were observed. Here, we demonstrate the impact of several commercially available codon optimization services, and compare to a targeted strategy. Using the targeted strategy, only codons known to have translational errors are modified. For an Fc‐fusion protein expressed in Escherichia coli, the targeted strategy, in combination with appropriate fermentation conditions, virtually eliminated misincorporation (proteins produced with a wrong amino acid sequence), and reduced the level of truncation. The use of full optimization using commercially available strategies reduced the initial errors, but introduced different misincorporations. However, truncation was higher using the targeted strategy than for most of the full optimization strategies. This targeted approach, along with monitoring of translation fidelity and careful attention to fermentation conditions is key to minimizing translational error and ensuring high‐quality expression. These findings should be useful for other biopharmaceutical products, as well as any other transgenic constructs where protein quality is important. Biotechnol. Bioeng. 2012; 109: 2770–2777. © 2012 Wiley Periodicals, Inc.
‘Artery-first’ approaches to pancreatoduodenectomy
Authors: Sanjay P , Takaori K , Govil S , Shrikhande S V , Windsor J A
Published: May 2012

Background

The technique of pancreatoduodenectomy (PD) has evolved. Previously, non-resectability was determined by involvement of the portal vein–superior mesenteric vein. Because venous resection can be achieved safely and with greater awareness of the prognostic significance of the status of the posteromedial resection margin, non-resectability is now determined by involvement of the superior mesenteric artery (SMA). This change, with a need for early determination of resectability before an irreversible step, has promoted the development of an ‘artery-first’ approach. The aim of this study was to review, and illustrate, this approach.

Methods

An electronic search was performed on MEDLINE, Embase and PubMed databases from 1960 to 2011 using both medical subject headings and truncated word searches to identify all published articles that related to this topic.

Results

The search revealed six different surgical approaches that can be considered as ‘artery first’. These involved approaching the SMA from the retroperitoneum (posterior approach), the uncinate process (medial uncinate approach), the infracolic region medial to the duodenojejunal flexure (inferior infracolic or mesenteric approach), the infracolic retroperitoneum lateral to the duodenojenunal flexure (left posterior approach), the supracolic region (inferior supracolic approach) and through the lesser sac (superior approach).

Conclusion

The six approaches described provide a range of options for the early determination of arterial involvement, depending on the location and size of the tumour, and before the ‘point of no return’. Whether these approaches will achieve an increase in the proportion of patients with negative margins, improve locoregional control and increase long-term survival has yet to be determined.
Production of Organic Fine‐Crystalline Particles by Using the Liquid‐Liquid Interface in an Emulsion
Authors: Takiyama H. , Ito K.
Published: May 2012

The method of anti‐solvent crystallization poses problems due to high local fluctuations in supersaturation affecting the quality of the generated crystals. In order to reduce the local fluctuations in supersaturation and to achieve homogeneous crystallization fields, the utilization of a liquid‐liquid interface in an emulsion is discussed. The purpose of this study was to establish the operating conditions of crystallization in order to produce fine crystals with the desired qualities by anti‐solvent crystallization in an emulsion. A quaternary system of taurine/water (original solvent)/hexane (anti‐solvent)/ethanol (coupled solvent) was used. As the experimental result, micro‐sized taurine crystals were obtained, and the operation conditions to obtain the desired crystal shape were clarified by utilizing the proposed quaternary phase diagram.
Crystal‐Packing Trends for a Series of 6,9,12,15,18‐Pentaaryl‐1‐hydro[60]fullerenes
Authors: Kennedy Robert D. , Halim Merissa , Khan Saeed I. , Schwartz Benjamin J. , Tolbert Sarah H. , Rubin Yves
Published: May 2012

The relationship between the size of the substituents of aryl groups in a series of fifteen 6,9,12,15,18‐pentaaryl‐1‐hydro[60]fullerenes and the solid‐state structures and packing motifs of these compounds has been analyzed. Pentaarylfullerenes have a characteristic “badminton shuttlecock” shape that causes several derivatives to crystallize into columnar stacks. However, many pentaarylfullerenes form non‐stacked structures with, for example, dimeric, layered, diamondoid, or feather‐in‐cavity relationships between molecules. Computational modeling gave a qualitative estimate of the best shape match between the ball and socket surfaces of each pentaarylfullerene. The best match was for pentaarylfullerenes with large, spherically shapedpara‐substituents on the aryl groups. The series of pentaarylfullerenes was characterized by single‐crystal X‐ray diffraction. A total of 34 crystal structures were obtained as various solvates and were categorized by their packing motifs.
Controllable Deposition of a Platinum Nanoparticle Ensemble on a Polyaniline/Graphene Hybrid as a Novel Electrode Material for Electrochemical Sensing
Authors: Qiu Jian‐Ding , Shi Ling , Liang Ru‐Ping , Wang Guo‐Chong , Xia Xing‐Hua
Published: May 2012

We demonstrate for the first time an interfacial polymerization method for the synthesis of high‐quality polyaniline‐modified graphene nanosheets (PANI/GNs), which represents a novel type of graphene/polymer heterostructure. The interfacial polymerization at a liquid–liquid interface allows PANI to grow uniformly on the surface of the GNs. An ultra‐high loading of Pt nanoparticles was then controllably deposited on the surface of the PANI/GNs to form a Pt/PANI/GNs hybrid. The obtained composites were characterized by scanning electron microscopy, transmission electron microscopy, energy‐dispersive spectrometry, X‐ray diffraction, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. The Pt/PANI/GNs hybrid shows excellent electrocatalytic activity toward methanol oxidation and oxygen reduction. H2O2 and glucose were used as two representative analytes to demonstrate the sensing performance of a Pt/PANI/GNs‐modified electrode. It is found that this sensing element shows high sensitivity and a low detection limit for H2O2 and glucose. The results demonstrate that the Pt/PANI/GNs hybrid may be an attractive and advanced electrode material with potential applications in the construction of electrochemical sensors and biosensors.
Facile Fabrication of a Graphene‐based Electrochemical Biosensor for Glucose Detection
Authors: Zhang Yanqin , Fan Youjun , Wang Shanshan , Tan Yiliang , Shen Xingcan , Shi Zujin
Published: May 2012

A simple and effective glucose biosensor based on immobilization of glucose oxidase (GOD) in graphene (GR)/Nafion film was constructed. The results indicated that the immobilized GOD can maintain its native structure and bioactivity, and the GR/Nafion film provides a favorable microenvironment for GOD immobilization and promotes the direct electron transfer between the electrode substrate and the redox center of GOD. The electrode reaction of the immobilized GOD shows a reversible and surface‐controlled process with the large electron transfer rate constant (ks) of 3.42±0.08 s−1. Based on the oxygen consumption during the oxidation process of glucose catalyzed by the immobilized GOD, the as‐prepared GOD/GR/Nafion/GCE electrode exhibits a linear range from 0.5 to 14 mmol·L−1 with a detection limit of 0.03 mmol·L−1. Moreover, it displays a good reproducibility and long‐term stability.
Interfacial Water Structure in Langmuir Monolayer and Gibbs Layer Probed by Sum Frequency Generation Vibrational Spectroscopy
Authors: Zhang Zhen , Guo Yuan
Published: May 2012

Langmuir monolayer and Gibbs layer exhibit surface‐active properties and it can be used as simple model systems to investigate the physicochemical properties of biological membranes. In this report, we presented the OH stretching vibration of H2O in the 4′′‐n‐pentyl‐4‐cyano‐p‐terphenyl (5CT), nonadecanenitrile (C18CN) Langmuir monolayer and compared them with CH3CN Gibbs layer at the air/water interface with polarization SFG‐VS. This study demonstrated that the hydrogen bond network is different in the Langmuir monolayer of 5CT, C18CN from CH3CN Gibbs layer at the air/water interface which showed two different water structures on the different surface layer. The results provided a deeper insight into understanding the hydrogen bond on the interfaces.
A Study of Interaction between Flavonoids and the Parallel Quadruplex Structure [d(TGGGGT)]4 by Electrospray Ionization Mass Spectrometry
Authors: Xu Niusheng , Yang Hongmei , Cui Meng , Song Fengrui , Liu Zhiqiang , Liu Shuying
Published: May 2012

In this study, electrospray ionization mass spectrometry (ESI‐MS) was used to investigate interaction of 21 flavonoids (10 aglycones and 11 glycosides) with the parallel quadruplex structure [d(TGGGGT)]4. Relative binding affinities of flavonoids toward [d(TGGGGT)]4 were estimated based on the fraction of bound DNA. It was found that [d(TGGGGT)]4 showed a binding preference to the flavonoid glycosides over flavonoid aglycones. It was deduced that glycosylation played a key role for the [d(TGGGGT)]4‐binding properties of flavonoid glycosides. Upon collision‐induced dissociation, complexes of flavonoid/[d(TGGGGT)]4 underwent the loss of flavonoids, suggesting an end‐stacking binding mode. The current work demonstrates that ESI‐MS is a powerful tool in the study of interaction between drugs and nucleic acids.
Synthsis of 4‐Piperidones via Multicomponent Double Mannich Reaction Catalyzed by I2
Authors: Jia Xiaodong , Chen Xiangning , Huo Congde , Peng Fangfang , Qing Chang , Wang Xicun
Published: May 2012

A multicomponent double Mannich reaction of amines, aldehydes and ketones was efficiently catalyzed by molecular iodine, producing a series of 4‐piperidones in a stereoselective way. A variety of amines, aldehydes and ketones were tolerated in this tandem process, including those with labile functinal groups. Further investigation of the reaction between alkyl‐imines and ketones showed that imines from amines and ketones were formed in situ and isomerized to enamine in the presence of molecular iodine to accelerate the corresponding Mannich addition.
NBS‐Promoted Sulfenylation of Sulfinates with Disulfides Leading to Unsymmetrical or Symmetrical Thiosulfonates
Authors: Liang Gaigai , Liu Miaochang , Chen Jiuxi , Ding Jinchang , Gao Wenxia , Wu Huayue
Published: May 2012

A highly practical method to access unsymmetrical and symmetrical thiosulfonates in moderate to excellent yields has been developed through NBS‐promoted sulfenylation of sulfinates with disulfides. The present process enables the use of two RS in RSSR and shows broad functional group tolerance, which represents an atom‐economical and practical procedure for the synthesis of thiosulfonates. A plausible mechanism for the role of NBS as a promoter for the cleavage of disul?des generating N‐(organothio)succinimide that then undergos facile sulenylation with sulfinates is proposed.
The Role of the Therapeutic Alliance in the Regulation of Emotion in Psychosis: An Attachment Perspective
Authors: Owens Karen Annette , Haddock Gillian , Berry Katherine
Published: May 2012

Objectives: This article aims to explore the value of attachment theory as a framework for understanding the ways in which the staff–patient relationship is associated with different methods of regulating emotion in individuals with a diagnosis of psychosis. Method: Patient participants with a diagnosis of schizophrenia, schizoaffective disorder or psychosis not otherwise specified and mental health workers were recruited from 24‐hour rehabilitation teams. Patient participants completed questionnaires assessing emotion regulation, attachment, therapeutic alliance and symptomatology. The therapeutic alliance was also assessed from mental workers' perspective. Results: Insecure attachment was significantly associated with greater difficulties in regulating emotions. A strong therapeutic alliance was associated with fewer difficulties in regulating emotions. Conclusions: Attachment is a useful theoretical construct for understanding psychosis, with evidence for a link between a positive staff–patient relationship and enhanced emotion regulation. Clinical implications of these findings are discussed. Copyright © 2012 John Wiley & Sons, Ltd.

Key Practitioner Message

The study supports a link between attachment organisation and psychosis, characterised by difficulties in emotion regulation.

A positive patient‐key worker relationship may facilitate the development of emotion regulation in this client group.

A key implication of these findings is the training of MDT staff in the implementation of attachment‐informed interventions.
The Origin of Molecular Mobility During Biomass Pyrolysis as Revealed by In situ 1H NMR Spectroscopy
Authors: Dufour Anthony , Castro‐Diaz Miguel , Brosse Nicolas , Bouroukba Mohamed , Snape Colin
Published: May 2012

The thermochemical conversion of lignocellulosic biomass feedstocks offers an important potential route for the production of biofuels and value‐added green chemicals. Pyrolysis is the first phenomenon involved in all biomass thermochemical processes and it controls to a major extent the product composition. The composition of pyrolysis products can be affected markedly by the extent of softening that occurs. In spite of extensive work on biomass pyrolysis, the development of fluidity during the pyrolysis of biomass has not been quantified. This paper provides the first experimental investigation of proton mobility during biomass pyrolysis by in situ 1H NMR spectroscopy. The origin of mobility is discussed for cellulose, lignin and xylan. The effect of minerals on cellulose mobility is also investigated. Interactions between polymers in the native biomass network are revealed by in situ 1H NMR analysis.
Sulforhodamine B restaining as a whole‐cell label allows visualizing one more fluorochrome and its application in assaying protein nucleocytoplasmic distribution
Authors: Han Fujun , Fan Lifei , Wang Xinsheng , Li Wei
Published: May 2012

Multiparametric image analysis is highly preferable in revealing complicated biological processes. The multiplexing capability is demanding and is limited by spectral overlap of fluorescent dyes and the number of fluorescent channels available in an imaging platform, especially when both nuclear and cytoplasmic staining are required for the analysis. Here, we introduce a retrospective method that enables cell labeling by restaining the cells with sulforhodamine B (SRB) using a positioning‐stage equipped microscope and an automated image registration technique. Using signal transducers and activator of transcription 1 (STAT1) nuclear translocation as an example, this method was shown to be able to improve the reliability and multiplexing capability of protein distribution assays. The application of this method in a three‐fluorescent channel platform is functionally equal to a conventional four‐color assay and enables the correlation between cellular distributions of two proteins expressed at very low levels to be detected. We have demonstrated this application using STAT3 and syndecan‐1. For the first time, we found that the two proteins were correlated at both the nuclear:cytoplasmic distribution and expression levels. This experimental direction could advance our understanding as to how these molecules function. The simplicity and automation of this method makes it easily applicable into other imaging assays. Other dyes can be used in a similar way as substitutes of SRB. © 2012 International Society for Advancement of Cytometry
Bivalent response to long‐term storage in liquid‐preserved boar semen: A flow cytometric analysis
Authors: Henning Heiko , Petrunkina Anna M. , Harrison Robin A. P. , Waberski Dagmar
Published: May 2012

The fertility of liquid‐preserved boar semen declines during storage at 17°C, insemination trials even indicating early losses in fertilizing ability within the first 24–48 h of storage. Standard semen parameters barely reflect these changes in semen quality, and new approaches for assessment of functional changes in stored spermatozoa are needed. Capacitation, the essential prefertilization step for spermatozoa in the female genital tract, is specifically induced in vitro by bicarbonate. Therefore, we have investigated changes in responsiveness of boar spermatozoa to bicarbonate during storage. Ejaculates of 14 boars were diluted in Beltsville thawing solution, cooled to 17°C and stored for 12, 24, 72, 120, and 168 h before investigation. At each time, basic semen quality was characterized by sperm motility and viability. Subsequently, washed subsamples were incubated in variants of an in vitro fertilization (IVF) medium and assessed for kinetic changes of viability (plasma membrane integrity) and intracellular calcium concentration using flow cytometry in combination with propidium iodide and Fluo‐3. By this means, it was possible to determine specific effects of bicarbonate and calcium on sperm subpopulations over incubation time. During storage, standard semen parameters remained on a high level. However, flow cytometric analysis of sperm responses to capacitating and control media revealed two opposing effects of storage. There was a loss of response to bicarbonate in part of the live sperm population but an increasing degree of instability in the rest. Assessment of response to capacitating media by flow cytometry appears a markedly more sensitive way of monitoring sperm functionality during storage than the standard semen parameters of motility and viability. © 2012 International Society for Advancement of Cytometry
Flow cytometer based on triggered supercontinuum laser illumination
Authors: Rongeat Nelly , Leproux Philippe , Couderc Vincent , Brunel Patrick , Ledroit Sylvain , Cremien Didier , Hilaire Stéphane , Huss Guillaume , Nérin Philippe
Published: May 2012

Multiple wavelength operation in a flow cytometer is an exciting way for cell analysis based on both fluorescence and optical scattering processing. For example, this multiparametric technique is currently used to differentiate blood cells subpopulations. The choice of excitation wavelengths matching fluorochrome spectra (it is currently the opposite) and the use of a broader range of fluorochromes can be made by taking advantage of a filtered supercontinuum white light source. In this study, we first wished to validate the use of a specific triggered supercontinuum laser in a flow cytometer based on white light scattering and electric sizing on human blood cells. Subsequently, to show the various advantages of this attractive system, using scattering effect, electrical detections, and fluorescence analysis, we realized cells sorting based on DNA/RNA stained by thiazole orange. Discrimination of white blood cells is efficiently demonstrated by using a triggered supercontinuum‐based flow cytometer operating in a “one cell‐one shot” configuration. The discriminated leukocyte populations are monocytes, lymphocytes, granulocytes, immature granulocytes, and cells having a high RNA content (monoblasts, lymphoblasts, and plasma cells). To the best of our knowledge, these results constitute the first practical demonstration of flow cytometry based on triggered supercontinuum illumination. This study is the starting point of a series of new experiments fully exploiting the spectral features of such a laser source. For example, the large flexibility in the choice of the excitation wavelength allows to use a larger number of fluorochromes and to excite them more efficiently. Moreover, this work opens up new research directions in the biophotonics field, such as the combination of coherent Raman spectroscopy and flow cytometry techniques. © 2012 International Society for Advancement of Cytometry
Efficacy of a Poly‐L‐Glutamic Acid‐Gemcitabine Conjugate in Tumor‐Bearing Mice
Authors: Kiew Lik Voon , Cheong Soon Keng , Ramli Ernidila , Sidik Khalifah , Lim Tuck Meng , Chung Lip Yong
Published: May 2012

Strategy, Management and Health Policy

Enabling Technology, Genomics, Proteomics
Preclinical Research
Preclinical Development Toxicology, Formulation Drug Delivery, Pharmacokinetics
Clinical Development Phases I‐III Regulatory, Quality, Manufacturing
Postmarketing Phase IV

This study assessed the in vivo antitumor efficacy of a polypeptide‐based poly‐L‐glutamic acid‐gemcitabine conjugate (PG‐G). PG‐G was synthesized by conjugating gemcitabine to poly‐L‐glutamic acid by a carbodiimide reaction. PG‐G was evaluated for its in vivo antitumor efficacy and toxicity using 4T1 murine breast tumor‐bearing mice. The antitumor effects of PG‐G were superior to those of unconjugated gemcitabine in both single and four‐consecutive dosing studies. Tumor regression was observed within 1 day after PG‐G administration and continued for 4–5 days. Thereafter, tumors grew at a slower rate compared with the unconjugated gemcitabine treatment group and other control groups. The main toxicity observed from the Berlin test was an apparent reversible weight loss of 10–12%. The unconjugated gemcitabine treatment group also demonstrated a similar, but reduced, weight loss trend. The present study demonstrates that the PG‐G formulation exhibits a significant antitumor activity in the aspects of tumor growth inhibition and shrinkage that is more robust than the parent drug and other control groups. Thus, the PG‐G dose regimen may be optimized to minimize side effects and render it a potential anticancer therapeutic.
Synthesis and Preliminary Structural and Binding Characterization of New Enantiopure Crown Ethers Containing an Alkyl Diarylphosphinate or a Proton‐Ionizable Diarylphosphinic Acid Unit
Authors: Székely György , Csordás Barbara , Farkas Viktor , Kupai József , Pogány Peter , Sánta Zsuzsanna , Szakács Zoltán , Tóth Tünde , Hollósi Miklós , Nyitrai József , Huszthy Péter
Published: May 2012

New enantiopure crown ethers containing either an ethyl diarylphosphinate moiety [(S,S)‐4 to (S,S)‐7] or a proton‐ionizable diarylphosphinic acid unit [(S,S)‐8 to (S,S)‐11] have been synthesized. Electronic circular dichroism (ECD) studies on the complexation of these new enantiopure crown ethers with the enantiomers of α‐(1‐naphthyl)ethylammonium perchlorate (1‐NEA) and with α‐(2‐naphthyl)ethylammonium perchlorate (2‐NEA) were also carried out. These studies showed appreciable enantiomeric recognition with heterochiral [(S,S)‐crown ether plus either (R)‐1‐ or (R)‐2‐NEA] preference. Theoretical calculations found three significant intermolecular hydrogen bonds in the complexes of (S,S)‐9. Furthermore, preference for heterochiral complexes was also observed, in good agreement with ECD results. Complex formation constants were determined by NMR titration for four selected crown ether/NEA pairs.
C–C Coupling of Acyclic Nitronates with Silyl Ketene Acetals under Silyl Triflate Catalysis: Reactivity Umpolung of Aliphatic Nitro Compounds
Authors: Smirnov Vladimir O. , Khomutova Yulia A. , Tartakovsky Vladimir A. , Ioffe Sema L.
Published: May 2012

TBSOTf‐promoted C–C coupling of alkyl and trialkylsilyl nitronates with silyl ketene acetals yields functionalized nitroso acetals. This conversion may serve as a new simple procedure to reverse the conventional reactivity of aliphatic nitro compounds. Preliminary results on the hydrogenation of nitroso acetals into amino acids derivatives, as well as TFA‐catalyzed transformations of nitroso acetals, are examined to prove the possible utility of this umpolung procedure.
Selection of Pharmaceutical Antioxidants by Hydrodynamic Voltammetry
Authors: Webster Gregory K. , Craig Robert A. , Pommerening Cynthia A. , Acworth Ian N.
Published: May 2012

Antioxidant compounds are routinely included in pharmaceutical formulations in order to minimize the oxidative degradation of the active pharmaceutical ingredient(s) (API). The effectiveness of the antioxidants being considered is often assessed by creating several formulations with the API(s) and single or multiple antioxidants in order to place each of these formulations on stability under accelerated conditions. This trial and error selection process is costly and time consuming, often taking weeks before the oxidation is observed at a detectable level. Using a flow injection coulometric detector based system, a potential tool has been developed to guide initial antioxidant selection for hindering the oxidative degradation for a given drug substance in its formulation environment. The relative potential for the API to be oxidized can be measured by matching the conditions of the coulometric experiment to the formulation matrix. Using this selection criterion, the choice of antioxidants to study for individual formations can be greatly narrowed, thus leading to a significant savings in development time and cost.
Damping‐adjusted combination rule for the response spectrum analysis of base‐isolated buildings
Authors: Muscolino Giuseppe , Palmeri Alessandro , Versaci Claudia
Published: May 2012

The classical response spectrum method continues to be the most popular approach for designing base‐isolated buildings, therefore avoiding computationally expensive nonlinear time‐history analyses. In this framework, a new method for the seismic analysis and design of building structures with base isolation system (BIS) is formulated and numerically validated, which enables one to overcome the main shortcomings of existing techniques based on the response spectrum method. The main advantages are the following: first, reduced computational effort with respect to an exact complex‐valued modal analysis, which is obtained through a transformation of coordinates in two stages, both involving real‐valued eigenproblems; second, effective representation of the damping, which is pursued by consistently defining different viscous damping ratios for the modes of vibration of the coupled BIS‐superstructure dynamic system; and third, ease of use, because a convenient reinterpretation of the combination coefficients leads to a novel damping‐adjusted combination rule, in which just a single response spectrum is required for the reference value of the viscous damping ratio. The proposed approach is specifically intended for design situations where (i) the dynamic behaviour of seismic isolators can be linearised and (ii) effects of nonproportional damping, as measured by modal coupling indexes, are negligible in the BIS‐superstructure assembly. Copyright © 2012 John Wiley & Sons, Ltd.
Copper uptake by the marine mussel Mytilus edulis in the presence of fulvic acids
Authors: Sánchez-Marín Paula , Lorenzo J. Ignacio , Mubiana Valentine K. , Blust Ronny , Beiras Ricardo
Published: May 2012

Copper uptake and accumulation by the marine mussel Mytilus edulis were studied at different Cu concentrations in chemically defined artificial seawater in the presence and absence of fulvic acids. Both short-term uptake of Cu by excised mussel gills and Cu accumulation in whole mussels after 24 h of exposure decreased in the presence of fulvic acids compared with their absence at similar dissolved Cu concentrations. Calculations of Cu speciation based on previous measurements of labile Cu by anodic stripping voltammetry demonstrated that Cu uptake and accumulation depended on the concentration of labile Cu, in agreement with the free ion activity model. No evidence of a significant uptake of Cu–fulvic acid complexes was observed. Environ. Toxicol. Chem. 2012; 31: 1807–1813. © 2012 SETAC
Effects of test design and temperature in a partial life-cycle study with the freshwater gastropod Potamopyrgus antipodarum
Authors: Macken Ailbhe , Le Page Gareth , Hayfield Amanda , Williams Timothy D. , Brown Rebecca J.
Published: May 2012

Potamopyrgus antipodarum is a candidate for a standardized mollusk partial life-cycle study. This is a comparative study of two test designs (microplate and beaker), with additional endpoints to the proposed guideline methods, for example, tracking of continuous reproductive output over 28 d and attributing it to individual female snails. In addition, an investigation of the effects of temperature (16, 20, and 25°C) on reproduction was also conducted employing the microplate design. Environ. Toxicol. Chem. 2012; 31: 1989–1994. © 2012 SETAC
Reed beds may facilitate transfer of tributyltin from aquatic to terrestrial ecosystems through insect vectors in the Archipelago Sea, SW Finland
Authors: Lilley Thomas M. , Meierjohann Axel , Ruokolainen Lasse , Peltonen Jani , Vesterinen Eero , Kronberg Leif , Nikinmaa Mikko
Published: May 2012

Due to their adsorptive behavior, organotin compounds (OTCs), such as tributyltin (TBT), are accumulated in aquatic sediments. They resist biodegradation and, despite a ban in 2008, are a potential source for future exposure. Sediment OTCs have mostly been measured from sites of known high concentrations such as ports, shipping lanes, and marine dredging waste sites. The possible flow of OTCs from marine to terrestrial ecosystems, however, has not been studied. In the present study, the authors assessed whether sediments in common reed beds (Phragmites australis) accumulate TBT and whether chironomid (Diptera: Chironomidae) communities developing in reed-bed sediments act as vectors in the transfer of TBT from aquatic to terrestrial ecosystems in the Airisto channel, Archipelago Sea. The authors also investigated whether distance from the only known source and depth and TBT concentration of the adjacent shipping lane affect reed-bed concentrations. Thirty-six sites along the Airisto channel were sampled at 2-km intervals with triplicate samples from reed beds and the adjacent shipping lane for sediment and seven reed-bed sites for chironomids, and these were analyzed with an solid phase extraction liquid chromatography tamdem mass spectrometry method. The closer to the source the sample site was, the higher the measured TBT concentrations were; and the deeper the shipping lane, the lower the concentration of TBT in reed-bed sediments. The chironomid TBT concentrations correlated with reed-bed sediment TBT concentrations and showed evidence of accumulation. Therefore, TBT may be transferred, through the food web, from aquatic to terrestrial ecosystems relatively close to a source through ecosystem boundaries, such as common reed beds, which are areas of high insect biomass production in the Archipelago Sea. Environ. Toxicol. Chem. 2012; 31: 1781–1787. © 2012 SETAC
Metal-based nanoparticles in soil: Fate, behavior, and effects on soil invertebrates
Authors: Tourinho Paula S. , van Gestel Cornelis A. M. , Lofts Stephen , Svendsen Claus , Soares Amadeu M. V. M. , Loureiro Susana
Published: May 2012

Metal-based nanoparticles (NPs) (e.g., silver, zinc oxide, titanium dioxide, iron oxide) are being widely used in the nanotechnology industry. Because of the release of particles from NP-containing products, it is likely that NPs will enter the soil compartment, especially through land application of sewage sludge derived from wastewater treatment. This review presents an overview of the literature dealing with the fate and effects of metal-based NPs in soil. In the environment, the characteristics of NPs (e.g., size, shape, surface charge) and soil (e.g., pH, ionic strength, organic matter, and clay content) will affect physical and chemical processes, resulting in NP dissolution, agglomeration, and aggregation. The behavior of NPs in soil will control their mobility and their bioavailability to soil organisms. Consequently, exposure characterization in ecotoxicological studies should obtain as much information as possible about dissolution, agglomeration, and aggregation processes. Comparing existing studies is a challenging task, because no standards exist for toxicity tests with NPs. In many cases, the reporting of associated characterization data is sparse, or missing, making it impossible to interpret and explain observed differences in results among studies. Environ. Toxicol. Chem. 2012; 31: 1679–1692. © 2012 SETAC
Effects of silver nanoparticles on zebrafish (Danio rerio) and Escherichia coli (ATCC 25922): A comparison of toxicity based on total surface area versus mass concentration of particles in a model eukaryotic and prokaryotic system
Authors: Bowman Christopher R. , Bailey Frank C. , Elrod-Erickson Matthew , Neigh Arianne M. , Otter Ryan R.
Published: May 2012

Silver nanoparticles (Ag NPs) have been classified as the most abundant NP found in commercial products. In the present study, zebrafish (Danio rerio) and bacteria (Escherichia coli; ATCC 25922) were used to test the size-dependent toxicological effects of Ag NPs, the effects of ionic silver versus Ag NPs, and Ag NP effects on mortality using mass concentration (mg/L) compared with total surface area (nm2/L). Several diameters of Ag NPs (20, 50, 110 nm) as well as AgNO3 were chosen as experimental treatments. Treated zebrafish embryos exhibited anomalies of the heart, namely, slower heart rates and pericardial edema. A size-dependent response was not observed in zebrafish when viewing mortality across all Ag NP treatments, although 20 nm elicited the highest incidence of abnormal motility and induced slower development. An Ag NP dose- and size-dependent response was observed in treated bacteria using mass concentration, with 20-nm Ag NP producing the highest mortality rate. In both zebrafish and bacteria, AgNO3 was shown to be more toxic than Ag NPs at equivalent concentrations. When total surface area of Ag NPs was used to gauge bacterial mortality, a total surface area-dependent, but not size-dependent, response was observed for all three Ag NPs used in the present study, with nearly 100% mortality observed once a total surface area of approximately 1E + 18 nm2/L was reached. This trend was not apparent, however, when measuring total surface area for zebrafish mortality. Environ. Toxicol. Chem. 2012; 31: 1793–1800. © 2012 SETAC
A distinct set of synaptic‐like microvesicles in atroglial cells contain VGLUT3
Authors: Ormel Lasse , Stensrud Mats Julius , Chaudhry Farrukh Abbas , Gundersen Vidar
Published: May 2012

There is increasing evidence for vesicular release of glutamate from astrocytes. We have previously demonstrated existence of VGLUT1 on astrocytic synaptic‐like microvesicles (SMLVs) in several brain regions indicating a role in astroglial glutamate release. As VGLUT3 is prominently expressed in non‐neuronal cells, this prompted us to investigate whether VGLUT3 is also involved in astroglial release of glutamate. Confocal microscopic investigations revealed that astrocytes in the hippocampus and the frontal cortex, as well as Bergmann glia in the cerebellum were labeled for VGLUT3. Immunogold cytochemistry showed that VGLUT3 gold particles were located over SMLVs in perisynaptic astrocytic and Bergmann glial processes. The specificity of the VGLUT3 immunoreactivity was demonstrated by abolished VGLUT3 labeling in astroglia in VGLUT3 knock‐out mice. Double immunogold labeling showed that astrocytic processes contained labeling for VGLUT3 and VGLUT1, but the antibodies labeled separate subpopulations of vesicles in the processes. The ratio of gold particle densities between glial processes and nerve terminals were higher for VGLUT3 than for VGLUT1, suggesting that VGLUT3 is particularly abundant in astrocytic processes. Thus, our data show that VGLUT3 localizes to a distinct set of SMLVs in perisynaptic astroglial processes and suggest that VGLUT3 is important for glutamate release from astrocytes. © 2012 Wiley Periodicals, Inc.