bluuebunny/crossref_metadata_2025 huggingface dataset:
Facile Synthesis of High‐Quality Plasma‐Reduced Graphene Oxide with Ultrahigh 4,4′‐Dichlorobiphenyl Adsorption Capacity
Authors: Wang Qi , Li Jiaxing , Song Ye , Wang Xiangke
Published: October 2012

High‐quality reduced graphene, termed PG, has been synthesized by a simple, low‐cost, and green plasma approach, and applied as adsorbent to remove 4,4′‐dichloribiphenyl (4,4′‐DCB) from aqueous solutions. As a comparison, the adsorption of 4,4′‐DCB on graphene oxide (GO) and multiwalled carbon nanotubes (MWCNTs) was also studied under the same experimental conditions. PG performs significantly better with regard to 4,4′‐DCB adsorption than GO and MWCNTs, or any reported nanomaterials, with a maximum adsorption capacity (qmax) of 1552 mg g−1 at pH 7.0. The high affinity of 4,4′‐DCB to PG is mainly a result of strong π–π interactions, as also confirmed by DFT calculations. The results reveal that PG sheets hold promise for the removal of persistent organic pollutants. We expect possible applications of this fast and mild plasma technique in the fabrication of nanomaterials and envisage their use in a variety of advanced chemical processes.
Intracellular surface‐enhanced Raman scattering probe based on gold nanorods functionalized with mercaptohexadecanoic acid with reduced cytotoxicity
Authors: Liu Min , Wang Zhuyuan , Zong Shenfei , Zhang Ruohu , Yang Jing , Cui Yiping
Published: October 2012

A surface‐enhanced Raman scattering (SERS) probe for intracellular detection was demonstrated by utilizing gold nanorods (GNRs) coated with p‐aminothiophenol as the Raman reporters. In this probe, to reduce the cytotoxicity of GNRs, cetyltrimethylammonium bromide (CTAB) molecules adsorbed on the surfaces of GNRs as ligands were replaced by mercaptohexadecanoic acid via a “round‐trip” phase change method. Such a ligand exchange can reduce the toxicity of the probe compared to the original CTAB‐stabilized GNRs, which were confirmed by both 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay and bright field view of HeLa cells. Meanwhile, the transmission electron microscopy images indicated that there is no significant morphologic change of GNRs before and after the ligand exchange. Moreover, its SERS performance was adequately retained after the incorporation of the probe into living HeLa cells. This new type of SERS probe is expected to have great potential in intracellular imaging or sensing applications.
Corporate Social Responsibility in China: a Preferential Stakeholder Model and Effects
Authors: Xun Jiyao
Published: October 2012

Research interest in examining corporate social responsibility (CSR) in developing economies is on the rise; however, our knowledge of the role of government in CSR remains limited. The aim of this paper is therefore to bridge this gap with an investigation into the specific CSR strategies that global firms have developed in the world's largest emerging economy and a nominally communist country, namely China. Drawing on institutional theory and a relational governance perspective, we posit that rather than adopting a canonical holistic CSR stakeholder model as typically observed in Western countries, these firms adopt a preferential stakeholder model using government‐aimed and consumer‐aimed CSR strategically. Our empirical study sampled 17 global retailers operating in China, with a dataset compiled to include their CSR web announcement data and firm performance data. The results of partial least squares modelling suggest that only government‐aimed CSR plays a salient role in enhancing retailers' performance. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment
Pharmacoresistant Cav2·3 (E‐type/R‐type) voltage‐gated calcium channels influence heart rate dynamics and may contribute to cardiac impulse conduction
Authors: Galetin Thomas , Tevoufouet Etienne E. , Sandmeyer Jakob , Matthes Jan , Nguemo Filomain , Hescheler Jürgen , Weiergräber Marco , Schneider Toni
Published: October 2012

Voltage‐gated Ca2+ channels regulate cardiac automaticity, rhythmicity and excitation–contraction coupling. Whereas L‐type (Cav1·2, Cav1·3) and T‐type (Cav3·1, Cav3·2) channels are widely accepted for their functional relevance in the heart, the role of Cav2·3 Ca2+ channels expressing R‐type currents remains to be elucidated.

We have investigated heart rate dynamics in control and Cav2·3‐deficient mice using implantable electrocardiogram radiotelemetry and pharmacological injection experiments. Autonomic block revealed that the intrinsic heart rate does not differ between both genotypes. Systemic administration of isoproterenol resulted in a significant reduction in interbeat interval in both genotypes. It remained unaffected after administering propranolol in Cav2·3(−|−) mice. Heart rate from isolated hearts as well as atrioventricular conduction for both genotypes differed significantly. Additionally, we identified and analysed the developmental expression of two splice variants, i.e. Cav2·3c and Cav2·3e. Using patch clamp technology, R‐type currents could be detected in isolated prenatal cardiomyocytes and be related to R‐type Ca2+ channels.

Our results indicate that on the systemic level, the pharmacologically inducible heart rate range and heart rate reserve are impaired in Cav2·3 (−|−) mice. In addition, experiments on Langendorff perfused hearts elucidate differences in basic properties between both genotypes. Thus, Cav2·3 does not only contribute to the cardiac autonomous nervous system but also to intrinsic rhythm propagation. Copyright © 2012 John Wiley & Sons, Ltd.
A 3D AgCl Hierarchical Superstructure Synthesized by a Wet Chemical Oxidation Method
Authors: Lou Zaizhu , Huang Baibiao , Ma Xiangchao , Zhang Xiaoyang , Qin Xiaoyan , Wang Zeyan , Dai Ying , Liu Yuanyuan
Published: October 2012

A novel 3D AgCl hierarchical superstructure, with fast growth along the 〈111〉 directions of cubic seeds, is synthesized by using a wet chemical oxidation method. The morphological structures and the growth process are investigated by scanning electron microscopy and X‐ray diffraction. The crystal structures are analyzed by their crystallographic orientations. The surface energy of AgCl facets {100}, {110}, and {111} with absorbance of Cl− ions is studied by density functional theory calculations. Based on the experimental and computational results, a plausible mechanism is proposed to illustrate the formation of the 3D AgCl hierarchical superstructures. With more active sites, the photocatalytic activity of the 3D AgCl hierarchical superstructures is better than those of concave and cubic ones in oxygen evolution under irradiation by visible light.
High Magnetic Moments in Manganese‐Doped Silicon Clusters
Authors: Ngan Vu Thi , Janssens Ewald , Claes Pieterjan , Lyon Jonathan T. , Fielicke André , Nguyen Minh Tho , Lievens Peter
Published: October 2012

We report on the structural, electronic, and magnetic properties of manganese‐doped silicon clusters cations, SinMn+ with n=6–10, 12–14, and 16, using mass spectrometry and infrared spectroscopy in combination with density functional theory computations. This combined experimental and theoretical study allows several structures to be identified. All the exohedral SinMn+ (n=6–10) clusters are found to be substitutive derivatives of the bare Sin+1+ cations, while the endohedral SinMn+ (n=12–14 and 16) clusters adopt fullerene‐like structures. The hybrid B3P86 functional is shown to be appropriate in predicting the ground electronic states of the clusters and in reproducing their infrared spectra. The clusters turn out to have high magnetic moments localized on Mn. In particular the Mn atoms in the exohedral SinMn+ (n=6–10) clusters have local magnetic moments of 4 μB or 6 μB and can be considered as magnetic copies of the silicon atoms. Opposed to other 3d transition‐metal dopants, the local magnetic moment of the Mn atom is not completely quenched when encapsulated in a silicon cage.
Molecular Gauge Blocks for Building on the Nanoscale
Authors: Grunder Sergio , Valente Cory , Whalley Adam C. , Sampath Srinivasan , Portmann Jürg , Botros Youssry Y. , Stoddart J. Fraser
Published: October 2012

Molecular gauge blocks, based on 1–7, 9–11 paraxylene rings, have been synthesized as part of a homologous series of oligoparaxylenes (OPXs) with a view to providing a molecular tool box for the construction of nano architectures—such as spheres, cages, capsules, metal–organic frameworks (MOFs), metal–organic polyhedrons (MOPs) and covalent–organic frameworks (COFs), to name but a few—of well‐defined sizes and shapes. Twisting between the planes of contiguous paraxylene rings is generated by the steric hindrance associated with the methyl groups and leads to the existence of soluble molecular gauge blocks without the need, at least in the case of the lower homologues, to introduce long aliphatic side chains onto the phenylene rings in the molecules. Although soluble molecular gauge blocks with up to seven consecutive benzenoid rings have been prepared employing repeating paraxylene units, in the case of the higher homologues it becomes necessary to introduce hexyl groups instead of methyl groups onto selected phenylene rings to maintain solubility. A hexyl‐doped compound with seven substituted phenylene rings was found to be an organogelator, exhibiting thermally reversible gelation and a critical gelation concentration of 10 mM in dimethyl sulfoxide. Furthermore, control over the morphology of a series of hexyl‐doped OPXs to give microfibers, microaggregates, or nanofibers, was observed as a function of their lengths according to images obtained by scanning electron microscopy. The modular syntheses of the paraphenylene derivatives rely heavily on Suzuki–Miyaura cross‐coupling reactions. The lack of π–π conjugation in these derivatives that is responsible for their enhanced solubilities was corroborated by UV/Vis and fluorescent spectroscopy. In one particular series of model OPXs, dynamic 1H NMR spectroscopy was used to probe the stereochemical consequences of having from one up to five axes of chirality present in the same molecule. The Losanitsch sequence for the compounds with 1–3 chiral axes was established, and a contemporary mathematical way was found to describe the sequence. The development of the ways and means to make molecular gauge building blocks will have positive repercussions on the control of nanostructures in general. Their incorporation into extended structures with the MOF‐74 topology provides an excellent demonstration of the potential usefulness of these molecular gauge blocks.
Prospective study on metabolic factors and risk of prostate cancer
Authors: Häggström Christel , Stocks Tanja , Ulmert David , Bjørge Tone , Ulmer Hanno , Hallmans Göran , Manjer Jonas , Engeland Anders , Nagel Gabriele , Almqvist Martin , Selmer Randi , Concin Hans , Tretli Steinar , Jonsson Håkan , Stattin Pär
Published: October 2012

BACKGROUND:

There are inconsistent data regarding the association between metabolic factors, separately and combined, and the risk of prostate cancer and death from prostate cancer.

METHODS:

In the Metabolic Syndrome and Cancer Project (Me‐Can), data on body mass index (BMI); blood pressure; and blood levels of glucose, cholesterol, and triglycerides were collected for 289,866 men. Cox proportional hazard models were used to calculate relative risks (RRs) by exposures in quintiles as well as for z scores (with a mean of 0 and a standard deviation of 1) together with a composite sum of scores to assess the combined effect of metabolic factors. RRs were corrected for random errors in measurement.

RESULTS:

During a mean follow‐up of 12 years, 6673 men were diagnosed with prostate cancer and 961 died of the disease. Men with high levels of glucose and triglycerides were found to have a decreased risk of prostate cancer: top versus bottom quintile of glucose: RR, 0.82 (95% confidence interval [95% CI], 0.62‐1.08; P value for trend = .03) and top versus bottom quintile of triglycerides: RR, 0.88 (95% CI, 0.74‐1.04; P value for trend = .001). High BMI, elevated blood pressure, and a high composite z score were found to be associated with an increased risk of death from prostate cancer: top versus bottom quintile of BMI: RR, 1.36 (95% CI, 1.08‐1.71); systolic blood pressure: RR, 1.62 (95% CI, 1.07‐2.45); and per 1‐unit increase of the composite z score: RR, 1.13 (95% CI, 1.03‐1.25).

CONCLUSIONS:

The authors found no evidence of an association between high levels of metabolic factors and the risk of prostate cancer, but high BMI, elevated blood pressure, and a composite score of all metabolic factors were associated with an increased risk of death from prostate cancer. Cancer 2012. © 2012 American Cancer Society.
Laser Mass Spectrometry with Circularly Polarized Light: Circular Dichroism of Molecular Ions
Authors: Logé Christoph , Boesl Ulrich
Published: October 2012

In recent experiments of resonance‐enhanced laser ionization, large differences between circular dichroism measured for molecular and fragment ions were found by several research groups for different molecular systems. In the case of 3‐methylcyclopentanone (3‐MCP) we attributed this effect to a large circular dichroism of the molecular ion. In the work presented here, this effect in 3‐MCP is studied by ion spectroscopy, by varying the neutral intermediate excited state involved in resonance‐enhanced multiphoton ionization (REMPI) and by performing REMPI‐induced measurements of circular dichroism at different laser pulse energies. It turns out that the dynamics of structural changes in the ionic ground state strongly influences the observed ionic circular dichroism.
Nitroanilines as Quenchers of Pyrene Fluorescence
Authors: Agudelo‐Morales Carlos E. , Silva Oscar F. , Galian Raquel E. , Pérez‐Prieto Julia
Published: October 2012

The quenching of pyrene and 1‐methylpyrene fluorescence by nitroanilines (NAs), such as 2‐, 3‐, and 4‐nitroaniline (2‐NA, 3‐NA, and 4‐NA, respectively), 4‐methyl‐3‐nitroaniline (4‐M‐3‐NA), 2‐methyl‐4‐nitroaniline (2‐M‐4‐NA), and 4‐methyl‐3,5‐dinitroaniline (4‐M‐3,5‐DNA), are studied in toluene and 1,4‐dioxane. Steady‐state fluorescence data show the higher efficiency of the 4‐NAs as quenchers and fit with a sphere‐of‐action model. This suggests a 4‐NA tendency of being in close proximity to the fluorophore, which could be connected with their high polarity/hyperpolarizability. In addition, emission and excitation spectra evidence the formation of emissive pyrene—NA ground‐state complexes in the case of the 4‐NAs and, in a minor degree, in the 2‐NA. Moreover, time‐resolved fluorescence experiments show that increasing amounts of NA decrease the pyrene fluorescence lifetime to a degree that depends on the NA nature and is larger in the less viscous solvent (toluene). Although the NA absorption and the pyrene (Py) emission overlap, we found no evidence of dipole–dipole energy transfer from the pyrene singlet excited state (1Py) to the NAs; this could be due to the low NA concentration used in these experiments. Transient absorption spectra show that the formation of the pyrene triplet excited state (3Py) is barely affected by the presence of the NAs in spite of their efficiency in 1Py quenching, suggesting the involvement of 1Py—NA exciplexes which—after intersystem crossing—decay efficiently into 3Py.
Two new power allocation schemes for an OFDM cognitive radio with no knowledge on primary users’ interference
Authors: Mahmoodi Seyed Eman , Abolhassani Bahman
Published: October 2012

In this paper, we propose two new power loading schemes for an OFDM cognitive radio (CR). The novelty of this paper is that the CR has no knowledge about the interference power introduced by primary users (PUs). In the first scheme, we maximize the total received signal power on all CR subcarriers as the objective function with the two constraints: (i) keeping the interference to the PUs below a given threshold, and (ii) allocating less than peak transmit power as the total power levels on all CR subcarriers. The second proposed scheme is similar to the first one with one more constraint, which is more power loading to the CR subcarriers experiencing higher ratio of channel power gain to the noise power. This third constraint results in increasing CR throughput (similar to the water‐filling scheme). Performances of these schemes are analyzed by numerical and simulation results, which illustrate that the two proposed schemes achieve relatively close to the optimal scheme (in which the secondary transmitter has full knowledge about PUs’ interference power) and outperform the scheme based on estimation of this interference power with an estimation error higher than a given threshold. Copyright © 2012 John Wiley & Sons, Ltd.
On the Chandra–Poram–Bose symbol error probability expression for coherent orthogonal M‐ary frequency shift keying
Authors: Côté François D. , Psaromiligkos Ioannis N. , Gross Warren J.
Published: October 2012

An expression for the average symbol error probability of coherent orthogonal M‐ary frequency shift keying in generalized fading was recently reported by Chandra, Poram, and Bose. We show that the expression is only exact for M = 2; it does, however, provide an accurate approximation for M > 2. By modifying the derivation of the reported expression, we derive a lower bound for M ⩽5 that has the same complexity as the reported expression, and we illustrate that, for M > 2, the expression of the derived bound provides an approximation that is also more accurate.Copyright © 2012 John Wiley & Sons, Ltd.
Identification of recombinant human relaxin‐2 in equine plasma by liquid chromatography‐high resolution mass spectrometry
Authors: Kwok Wai Him , Ho Emmie N. M. , Leung Gary N. W. , Wong April S. Y. , Yue Samuel K. , Wan Terence S. M.
Published: October 2012

Relaxin (RLX) is a peptide hormone belonging to the relaxin‐like peptide family. Relaxin‐2 (RLX‐2), a heteromeric polypeptide consisting of an A‐chain (24 amino acids) and a B‐chain (29 amino acids) linked together by two inter‐chain disulfide bonds, is the main circulating RLX hormone in human. Due to its ability to dilate blood vessels surrounding the smooth muscles via induction of nitric oxide resulting in the increase of blood and oxygen supplies to the muscles, it may enhance athletic performance and is therefore banned in horseracing, equestrian competitions, and human sports. In order to control the abuse of rhRLX‐2, a definitive method is required to detect and confirm the presence of rhRLX‐2 in biological samples. This paper describes, for the first time, the detection and confirmation of rhRLX‐2 in equine plasma by liquid chromatography‐high resolution mass spectrometry (LC‐HRMS) after immunoaffinity extraction. rhRLX‐2 could be detected at less than 0.1 ng/ml, and confirmed at less than 0.2 ng/ml in plasma samples. Copyright © 2012 John Wiley & Sons, Ltd.
An integrated shunt‐type MEMS switch with a submicron narrow gap
Authors: Yamamoto Shoji , Maeda Kazuya , Suzuki Kenichiro
Published: October 2012

Shunt‐type MEMS resistive switches have good performance, low loss, and high isolation in a wide frequency band. However, like other MEMS electrostatically driven switches, they suffer from a high driving voltage. The decrease of the gap between the driving electrodes causes a stronger electrostatic force, which is useful for decreasing the driving voltage. On the other hand, the reduction of the gap causes another problem, a decrease in isolation. In this paper, the influence of gap reduction on the performance of MEMS switches is investigated. We fabricated a switch with a gap of 0.9 μm and compared it with another switch having a gap of 2 μm. The measured results showed that the fabricated narrow gap switches had RF frequency characteristics as good as the 2‐μm gap switches. This is owing to the slits formed in a moving electrode over a transmission line. © 2012 Wiley Periodicals, Inc. Electron Comm Jpn, 95(11): 40–48, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.11417
Synthesis of Carbamates by Direct C–H Bond Activation of Formamides
Authors: Barve Balaji D. , Wu Yang‐Chang , El‐Shazly Mohamed , Chuang Da‐Wei , Chung Yu‐Ming , Tsai Yi‐Hong , Wu Shou‐Fang , Korinek Michal , Du Ying‐Chi , Hsieh Chi‐Ting , Wang Jeh‐Jeng , Chang Fang‐Rong
Published: October 2012

Copper catalysed oxidative coupling reaction of formamides with β‐keto esters and 2‐carbonyl‐substituted phenols successfully proceeded through direct C–H bond activation of formamides. The corresponding carbamates were formed with high stereoselectivity under mild reaction conditions. This protocol was successfully applied to the synthesis of three novel halogenated carbamates and a carbaryl insecticide derivative. Our results suggest the use of 6.0 equiv. TBHP is crucial for this type of reaction.
Contemporary sample stacking in analytical electrophoresis
Authors: Šlampová Andrea , Malá Zdena , Pantůčková Pavla , Gebauer Petr , Boček Petr
Published: October 2012

Sample stacking is a term denoting a multifarious class of methods and their names that are used daily in CE for online concentration of diluted samples to enhance separation efficiency and sensitivity of analyses. The essence of these methods is that analytes present at low concentrations in a large injected sample zone are concentrated into a short and sharp zone (stack) in the separation capillary. Then the stacked analytes are separated and detected. Regardless of the diversity of the stacking electromigration methods, one can distinguish four main principles that form the bases of nearly all of them: (i) Kohlrausch adjustment of concentrations, (ii) pH step, (iii) micellar methods, and (iv) transient ITP. This contribution is a continuation of our previous reviews on the topic and brings an overview of papers published during 2010–2012 and relevant to the mentioned principles (except the last one which is covered by another review in this issue).
3‐P⩵O‐Functionalized Phospholane 1‐Oxides by the Michael Reaction of 1‐Phenyl‐2‐phospholene 1‐Oxide and Dialkyl Phosphites, H‐Phosphinates, or Diphenylphosphine Oxide
Authors: Jablonkai Erzsébet , Drahos László , Drzazga Zbigniew , Pietrusiewicz K. Michal , Keglevich György
Published: October 2012

The addition of dialkyl phosphites, H‐phosphinates, and diphenylphosphine oxide on the β carbon atom of the not too reactive double bond of 1‐phenyl‐2‐phospholene 1‐oxide was carried out in two ways. According to the first approach (A), the P‐reagents were activated by trimethylaluminum prior to the Michael addition. The second method (B) involved the microwave(MW)‐assisted solventless reaction of the P‐species with the phospholene oxide. In general, method A was more efficient and more selective than route B. However, the addition of dialkyl phosphites and diphenylphosphine oxide could also be accomplished well under MW conditions. The disadvantage of the MW‐assisted approach is that the Michael adducts are formed as a mixture of isomers. The 3‐P⩵O‐phospholane oxides are novel products, and among these, the bis(phosphine oxide) is the precursor of the bidentate P‐ligand LuPhos.
A Novel Colorimetric and Fluorescent pH Sensor Derived from Iminocoumarin and Thiophene‐Carboxaldehyde
Authors: Li Hongqi , Guo Jian , Zhang Xuebin , Chen Zhen
Published: October 2012

A novel colorimetric and fluorescent pH sensor derived from iminocoumarin and thiophene‐carboxaldehyde was designed and synthesized. The structures of the dye and related compounds were characterized by IR, 1H NMR, 13C NMR, and mass spectra. Color change from green to yellow of the new sensor solution in ethanol–water with the decrease in the pH value from 7 to 2 was observed by the naked eye. Under acidic conditions, the intensity of the maximum fluorescence emission peak of the sensor increased gradually with the decrease in the acidity of the solution (the increase in the pH value from 2 to 7) and attained to the maximum value at about pH 6. Under basic conditions, the fluorescence intensity of the emission peak of the sensor did not exhibit a distinct change at pH ≤ 11.85, and the fluorescence was quenched at pH 13.36, concomitant with the green color of the solution turning pale. The sensor can be used as a fluorescent pH probe in the presence of common metal cations and anions without interference.
GA/GB Fold switching may modulate fatty acid transfer from human serum albumin to bacteria
Authors: Polticelli Fabio , Caprari Silvia , Gianni Stefano , Ascenzi Paolo
Published: October 2012

Human serum albumin (HSA) accounts for most of the functions of plasma. Among others, HSA serves as a carrier and a solubilizer for many endogenous and exogenous ligands, including fatty acids (FAs) as well as peptides and proteins such as the GA module of the bacterial poly(A)‐binding (PAB) protein. Although the biological function(s) of the GA module of the bacterial PAB protein is unknown, the acquisition of the GA module adds selective advantages to the bacterium in terms of growth rate and increase in virulence, probably by providing the bacteria with FAs and, possibly, other nutrients transported by HSA. Here, we hypothesize that the GA module may undergo a structural transition from the all‐α form to the 4β+α form typical of the GB domains upon binding of a FA molecule, as part of the mechanism which allows the bacterial PAB protein to extract FAs from HSA. © 2012 IUBMB. IUBMB Life, 64(11): 885–888, 2012
Selenium‐containing amino acids as direct and indirect antioxidants
Authors: Rahmanto Aldwin Suryo , Davies Michael J.
Published: October 2012

Selenium is a trace element essential for normal physiological processes. Organic selenium‐containing amino acids, such as selenocysteine (Sec) / selenocystine and selenomethionine (SeMet, the major dietary form), can provide antioxidant benefits by acting both as direct antioxidants as well as a source of selenium for synthesis of selenium‐dependent antioxidant and repair proteins (e.g., glutathione peroxidases, thioredoxin reductases, methionine sulfoxide reductases). The direct antioxidant actions of these amino acids arise from the nucleophilic properties of the ionized selenol (RSe−, which predominates over the neutral form at physiological pH values) and the ease of oxidation of Sec and SeMet. This results in higher rate constants for reaction with multiple oxidants, than for the corresponding thiols/thioethers. Furthermore, the resulting oxidation products are more readily and rapidly reversed by both enzyme and nonenzymatic reactions. The antioxidant effects of these seleno species can therefore be catalytic. Seleno amino acids may also chelate redox‐active metal ions. The presence of Sec in the catalytic site of selenium‐dependent antioxidant enzymes enhances the kinetic properties and broadens the catalytic activity of antioxidant enzymes against biological oxidants when compared with sulfur‐containing species. However, while normal physiological selenium levels afford protection, when compared with deficiency, excessive selenium may induce damage and adverse effects, with this being manifest, for example, as an increased incidence of type 2 diabetes. Further studies examining the availability of redox‐active selenium species and their mechanisms and kinetics of action are therefore of critical importance in the potential development of seleno species as a therapeutic strategy. © 2012 IUBMB. IUBMB Life, 64(11): 863–871, 2012
FHL family members suppress vascular endothelial growth factor expression through blockade of dimerization of HIF1α and HIF1β
Authors: Lin Jing , Qin Xi , Zhu Ziman , Mu Jinsong , Zhu Lingling , Wu Kuiwu , Jiao Huabo , Xu Xiaojie , Ye Qinong
Published: October 2012

Four and a half LIM domain (FHL) proteins belong to a family of LIM‐only proteins that have been implicated in the development and progression of various types of cancers. However, the role of FHL proteins in tumor angiogenesis remains to be elucidated. Herein, we demonstrate that FHL1‐3 decrease the promoter activity and expression of vascular endothelial growth factor (VEGF), the key regulator of angiogenesis in cancer growth and progression as well as an important target gene of the transcription factor hypoxia‐inducible factor 1 (HIF1α/HIF1β). FHL1‐3 interacted with HIF1α both in vitro and in vivo. A single LIM domain of FHL1 was sufficient for its interaction with HIF1α. FHL1 interacted with the HIF1α region containing basic helix‐loop‐helix (bHLH) motif and PER‐ARNT‐SIM domain, both of which aid in dimerization with HIF1β and DNA binding. FHL1‐3 inhibited HIF1 transcriptional activity and HIF1‐mediated VEGF expression in a hypoxia‐independent manner. Moreover, FHL1 blocked HIF1α‐HIF1β heterodimerization and HIF1α recruitment to the VEGF promoter. These data suggest that FHL proteins are involved in negative regulation of VEGF possibly by interfering with the dimerization and DNA binding of HIF1 subunits and may play an important role in tumor angiogenesis. © 2012 IUBMB. IUBMB Life, 64(11): 921–930, 2012
Comparative in vivo study of commercially pure Ti implants with surfaces modified by laser with and without silicate deposition: Biomechanical and scanning electron microscopy analysis
Authors: Souza Francisley A. , Queiroz Thallita P. , Guastaldi Antônio C. , Garcia‐Júnior Idelmo R. , Magro‐Filho Osvaldo , Nishioka Renato S. , Sisti Karin E. , Sonoda Celso K.
Published: October 2012

The purpose of this study was to evaluate commercially pure titanium implant surfaces modified by laser beam (LS) and LS associated with sodium silicate (SS) deposition, and compare them with machined surface (MS) and dual acid‐etching surfaces (AS) modified. Topographic characterization was performed by scanning electron microscopy–X‐ray energy dispersive spectroscopy (SEM–EDX), and by mean roughness measurement before surgery. Thirty rabbits received 60 implants in their right and left tibias. One implant of each surface in each tibia. The implants were removed by reverse torque for vivo biomechanical analysis at 30, 60, and 90 days postoperative. In addition, the surface of the implants removed at 30 days postoperative was analyzed by SEM–EDX. The topographic characterization showed differences between the analyzed surfaces, and the mean roughness values of LS and SS were statistically higher than AS and MS. At 30 days, values removal torque LS and SS groups showed a statistically significant difference (p < 0.05) when compared with MS and AS. At 60 days, groups LS and SS showed statistically significant difference (p < 0.05) when compared with MS. At 90 days, only group SS presented statistically higher (p < 0.05) in comparison with MS. The authors can conclude that physical chemistry properties and topographical of LS and SS implants increases bone‐implant interaction and provides higher degree of osseointegration when compared with MS and AS. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 76–84, 2013.
Synthesis and characterization of Bi2O3/HSA core‐shell nanoparticles for X‐ray imaging applications
Authors: Aviv Hagit , Bartling Soenke , Grinberg Igor , Margel Shlomo
Published: October 2012

Bismuth oxide nanoparticles of 12.1 ± 3.0 nm diameter were prepared by thermal decomposition of bismuth acetate dissolved in ethylene glycol in the presence of an oxidizing agent. Functionalization and stabilization of the hydrophobic Bi2O3 nanoparticles was accomplished by coating these core nanoparticles with human serum albumin (HSA), via a precipitation process. The formed Bi2O3/HSA core‐shell nanoparticles were of 15.2 ± 3.5 nm diameter. Elemental analysis measurements indicated that the bismuth weight % of the Bi2O3/HSA core‐shell nanoparticles is 72.9. The crystalline structure of these nanoparticles was examined by XRD. The radiopacity of these nanoparticles was demonstrated in vitro and in vivo by a CT scanner. In ovo and in vivo trials proved the safety of these Bi2O3/HSA core‐shell nanoparticles. In the future, we plan to extend this study particularly for molecular imaging applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 131–138, 2013.
Synthesis, Characterization and Antimicrobial Activity of a New Aromatic Sulfonyl Hydrazone Derivative and Its Transition Metal Complexes
Authors: Güzin Aslan H. , Karacan Nurcan , Aslan Ertuğrul
Published: October 2012

In this study, benzenesulfonicacid‐1‐methylhydrazide (bsmh) derivatives such as 2‐hydroxy‐1‐naphtaldehydebenzenesulfonylhydrazone (Hnafbsmh) and its Ni(II), Pd(II), Pt(II), Cu(II), Co(II) complexes were synthesized. The structures of these complexes were investigated using elemental analyses (FT‐IR, LC‐MS, UV‐VIS), magnetic susceptibility and conductivity measurement techniques. The complexes were found to have general compositions [ML2]. All the synthesized complexes were evaluated in vitro as antimicrobial agents against representative strains of six gram‐positive and four gram‐negative bacteria and as an antifungal agent by disc diffusion methods. All the bacteria and fungi studied were screened against some commercial antibiotics to compare them with our chemical's zone diameters.
Preparation and Application of Immobilized Fullerene C60‐Heparin for Anticoagulation of Blood
Authors: Lin Tsui‐Lien , Wen Hsiang‐Ping , Shih Chun‐Che , Shih Jeng‐Shong
Published: October 2012

The interaction between fullerene C60 and heparin was studied using a fullerene C60‐coated piezoelectric quartz crystal sensor. The irreversible response of the piezoelectric quartz crystal was found which could be attributed to the quite strong adsorption of heparin onto the C60 molecule. Immobilized fullerene C60‐Heparin was prepared and successfully applied as a good inhibitor for blood clotting. Like solvated heparin, both wet and dry C60‐heparin solid all demonstrated excellent ability of anticoagulation of blood. The blood clotting time with C60‐heparin solid was found to be > 7 days, while only 17.9 min required for blood clotting time in the absence of C60‐heparin solid. Furthermore, the C60‐heparin coated artificial PVC blood vessels were prepared by coating fullerene C60 onto the surface of artificial PVC blood vessels, followed by the adsorption of water solvated heparin onto the fullerene C60 molecule to form C60‐heparin coating. The blood clotting time of blood in artificial PVC blood vessels with C60‐heparin coating was found to be > 30 days, while only ≤ 30 min. of blood clotting time without the C60‐Heparin coating was observed. The C60‐heparin coated artificial PVC blood vessels can be expected to be employed in human body for the anticoagulation of blood.
Fabrication of Atrazine Molecularly Imprinted Polymer Microsphere by Two Step Seed Swelling Polymerization Method
Authors: Chen Jun , Bai Lianyang , Zhang Yijun , Chen Na , Zhang Yuping
Published: October 2012

Atrazine molecularly imprinted polymer microspheres (MIPMs) were fabricated by two step seed swelling polymerization method, using atrazine as a template molecule, methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EDMA) as a crosslinking agent and toluene/dodecanol as a porogenic agent and a series of MIPMs with even particle size of 3‐5 μm and good dispersivity could be obtained under the optimal condition. Equilibrium binding experiments were comparably studied about the binding capacity of the resulted polymers. We packed the polymers into empty chromatographic steel tube columns (2.1 mm I.D. × 10 cm) to prepare liquid chromatographic columns used for the evaluation of specificity with similar structure compounds. The proposed method has been successfully applied to the determination of limited atrazine in water samples. The results showed that a good linear relationship of atrazine was maintained within 0.1‐20 mg/L (r = 0.9992), the sample recovery was in a range of 92.1‐102.0%, with a RSD lower than 5% (n = 6) and a detection limit of 0.041 mg/L.
ENVIRONMENTALLY INDUCED MIGRATION, VULNERABILITY AND HUMAN SECURITY: CONSENSUS, CONTROVERSIES AND CONCEPTUAL GAPS FOR POLICY ANALYSIS
Authors: Assan Joseph Kweku , Rosenfeld Therese
Published: October 2012

This Policy Arena examines the consensus, controversies and some conceptual gaps associated with how policy approaches environmentally induced migration and human security concerns associated with individuals displaced as a result of climatic variability. This introductory paper discusses the theme from a historical approach to policy analysis of the subject by looking at three main areas of policy concern. The trilogy of discord are related to first, the absence of recognised definition of this phenomenon; second, the disagreement over the number of environmental migrants; and third, the diverse legal perspectives. It is not a coincidence that these traditional three thematic issues should remain controversial as they each relate to one another; with no recognised definitions, no precise criterions can be set out to calculate the number of environmental migrants, and consequently, no rigorous legal framework can be implemented to deal with environmentally induced migration. Although recent research projects led by governments and international organisations have chosen to move beyond the question of terminology by providing crucial data on the topic, there is the need to arrive at some internationally recognised consensus on the three core issues linked to the topic of environmental migration in order to legitimise the field. Such a step will also facilitate policy efforts at addressing environmental migration at the national and international levels. Copyright © 2012 John Wiley & Sons, Ltd.
Antioxidant activity of protein hydrolysates from whole anchovy sprat (Clupeonella engrauliformis) prepared using endogenous enzymes and commercial proteases
Authors: Ovissipour Mahmoudreza , Rasco Barbara , Shiroodi Setareh Ghorban , Modanlow Maryam , Gholami Sanaz , Nemati Mahrokh
Published: October 2012

Background

The antioxidant activity and chemical properties of fish protein hydrolysates (FPHs) prepared from anchovy sprat (Clupeonella engrauliformis) using endogenous enzymes (autolysis) and commercial proteases were investigated.

Results

The highest degree of hydrolysis (DH) was observed with Alcalase® and papain and the highest protein recovery (PR) with Alcalase® and bromelain. FPH yield was highest with Alcalase® (82.3%) and lowest with autolysis (63.64%). Increased DH resulted in increased FPH yield (R2 = 0.77). The highest oil recovery was observed with bromelain (6.41%) and the lowest with autolysis (3.58%). Antioxidant activity determined by DPPH, reducing power and ferrous chelation assays was highest in bromelain, Promod® and papain FPHs respectively. The highest ABTS activity was observed in Alcalase® FPH, followed by Promod® and Protamex™ FPHs. The lowest antioxidant activity was observed in autolysed and Flavourzyme® FPHs (P > 0.05). Heavy metals (arsenic, lead and mercury) were recorded at levels below the regulatory limits established by the FDA.

Conclusion

Anchovy sprat hydrolysates showed high antioxidant activities and amino acid contents and low heavy metal concentrations, indicating that they have high potential for use in human and animal diets. The high antioxidant activities are related to the high levels of hydrophobic amino acids found in this study.© 2012 Society of Chemical Industry
U13C cell extract of Pichia pastoris – a powerful tool for evaluation of sample preparation in metabolomics
Authors: Neubauer Stefan , Haberhauer‐Troyer Christina , Klavins Kristaps , Russmayer Hannes , Steiger Matthias G. , Gasser Brigitte , Sauer Michael , Mattanovich Diethard , Hann Stephan , Koellensperger Gunda
Published: October 2012

Quantitative metabolic profiling is preceded by dedicated sample preparation protocols. These multistep procedures require detailed optimization and thorough validation. In this work, a uniformly 13C‐labeled (U13C) cell extract was used as a tool to evaluate the recoveries and repeatability precisions of the cell extraction and the extract treatment. A homogenous set of biological replicates (n = 15 samples of Pichia pastoris) was prepared for these fundamental experiments. A range of less than 30 intracellular metabolites, comprising amino acids, nucleotides, and organic acids were measured both in monoisotopic 12C and U13C form by LC‐MS/MS employing triple quadrupole MS, reversed phase chromatography, and HILIC. Recoveries of the sample preparation procedure ranging from 60 to 100% and repeatability precisions below 10% were obtained for most of the investigated metabolites using internal standardization approaches. Uncertainty budget calculations revealed that for this complex quantification task, in the optimum case, total combined uncertainty of 12% could be achieved. The optimum case would be represented by metabolites, easy to extract from yeast with high and precise recovery. In other cases the total combined uncertainty was significantly higher.
Synthesis of (Bio)‐Degradable Poly(β‐thioester)s via Amine Catalyzed Thiol−Ene Click Polymerization
Authors: Vandenbergh Joke , Ranieri Kayte , Junkers Tanja
Published: October 2012

The well‐known thiol‐ene click reaction is used to polymerize dithiols and diacrylate monomers. Using catalytic amounts of hexylamine, poly(ester‐sulfide)s are synthesized via consecutive Michael additions between 1,4‐butanedithiol and 1,6‐hexanediol diacrylate. The molecular weight of the polymers is controlled by the stoichiometric balance of the reagents and by optimizing reaction time. Maximum conversion is achieved at close to 20 min at room temperature. Thermal characterization of the polymer shows a melting temperature of 53 °C and good thermal stability of up to 200 °C. The poly(β‐thioester) readily degrades when in contact with acetic acid or NaOH solutions, but also degradation under more biological relevant conditions is indicated by partial hydrolysis of the ester linkages in phosphate buffers.
pH‐Responsive Hyperbranched Copolymers from One‐Pot RAFT Copolymerization
Authors: Tai Hongyun , Duvall Craig L. , Hoffman Alan S. , Stayton Patrick S. , Wang Wenxin
Published: October 2012

The synthesis of new pH‐responsive hyperbranched copolymers via one pot RAFT copolymerization of PAA and a branching co‐monomer PEGDA ($\overline {M} _{{\rm n}} $ = 258 Da) is reported. Three copolymers are prepared at monomer feed molar ratios [PAA]0/[PEGDA]0 = 99/1, 90/10, and 80/20. The resultant poly(PAA‐PEGDA) copolymers are characterized by 1H NMR, GPC, and DLS. These hyperbranched copolymers demonstrate composition‐ and size‐dependent membrane disruptive properties by red blood cell hemolysis assay.

magnified image
Functional Properties of Extruded Nanocomposites Based on Cassava Starch, Polyvinyl Alcohol and Montmorillonite
Authors: Debiagi Flávia , Mali Suzana
Published: October 2012

Summary: The objectives of this work were to produce expanded nanocomposites based on cassava starch, polyvinyl alcohol (PVA) and sodium montmorillonite (Na‐MMT). The nanocomposites were characterized according to their expansion index (EI), density, water absorption capacity (WAC), mechanical properties and crystallinity. The nanocomposites were prepared in a single‐screw extruder using different starch contents (97.6–55.2 g/100 g formulation), PVA (0–40 g/100 g formulation) and Na‐MMT (0–4.8 g/100 g formulation). Glycerol (20 g/100 g formulation) was used as plasticizer. The addition of Na‐MMT and PVA resulted in an increase of EI and mechanical strength of the foams. Na‐MMT and PVA addition resulted in less WAC of the samples. The studied processing conditions resulted in a good nanoclay dispersion, leading to the formation of an intercalated structure.
Rheological and Morphological Properties of Carboxymethylcellulose/Starch Blends with or without ZnO and Their Applications as Inoculant Carrier
Authors: da Silva Coutinho Marcio , da Silva Danielle Cristina Fernandes , Xavier Gustavo Ribeiro , Rumjanek Norma Gouvêa , de Oliveira Paulo Jansen
Published: October 2012

Summary: Using controlled shear‐rate testing ramps, this study investigates the rheological properties of carboxymethycellulose (CMC)/starch blends, with and without zinc oxide (ZnO). Viscosity decreased as the amount of starch increased and after adding 1% ZnO. The creep and recovery tests indicated that, with increasing starch content, there was a decrease in elasticity and the viscosity zero shear rate. The results also showed, in the temperature range between 25 and 70 °C, an inversion occurred in the elastic and viscous moduli behavior, obeying the Arrhenius equation. The addition of ZnO affects the viscoelastic behavior and the morphology of the blends. The best survival results were obtained for samples 50/50 and 60/40 wt% (CMC/starch).
Petroleum Absorbers Based on CNSL, Furfural and Lignin – The Effect of the Chemical Similarity on the Interactions among Petroleum and Bioresins
Authors: Ferreira Letícia P. , Moreira Andrei N. , Delazare Thaís , Oliveira Geiza. Esperandio , Souza Jr. Fernando Gomes
Published: October 2012

Summary: The petroleum has become our most important source of energy since the mid‐1950s. It is due to its high energy density, easy transportability and relative abundance. However, along extraction, storage or transportation of oil, spill accidents may happen. This kind of accident causes severe impacts on the environment, being directly responsible for the destruction of the marine life, which affects the fishing and even tourism industries. Main goal of this work is related to the use of renewable sources aiming to obtain “absorbent green materials”. These materials were synthesized by a typical phenolic resin polycondensation route using cashew nut shell liquid (CNSL) as main phenolic compound. Focused on keep the green characteristic of the materials, furfuraldehyde from hemicellulose was used as aldehyde and the reaction was catalyzed using a small amount of sulfuric acid. Resins were characterized using Optical Microscopy, Scanning Electron Microscopy, Infrared Spectroscopy with Fourier Transformed (FTIR) and density tests. In addition, contraction of the oil spilled was studied in presence of resins. Obtained results demonstrated that synthesized resins present a good chemical similarity with oil, which produces a good interaction among resins and oil, making easy the contraction of the oil spot on the water and, consequently, the removal process of oil spilled on water.
Extraction and Characterization of Cellulose Nanowhiskers from Balsa Wood
Authors: Morelli Carolina Lipparelli , Marconcini José Manoel , Pereira Fabiano Vargas , Bretas Rosario Elida Suman , Branciforti Márcia Cristina
Published: October 2012

Summary: In this study cellulose nanowhiskers were obtained from balsa wood. For this purpose, fibers of balsa wood were exposed to hydrolysis reactions for lignin and hemicellulose digestion and acquisition of nano‐scale cellulose. Transmission electron microscopy (TEM) results demonstrated that the obtained cellulose nanocrystals had average length and thickness of 176 (±68 nm) and 7.5 (±2.9 nm), respectively. Infrared spectroscopy (FTIR) and wide angle x‐ray diffraction (WAXD) showed that the process for extracting the nanowhiskers digested nearly all the lignin and hemicellulose from the balsa fiber and still preserved the aspect ratio and crystallinity satisfactory enough for future application as nanofillers in polymer nanocomposites. The thermogravimetric analysis (TGA) showed that the onset temperature of thermal degradation of the cellulose nanocrystals (226 °C) was higher than the onset temperature of the balsa fiber (215 °C), allowing its use in molding processes with polymers melts.