bluuebunny/crossref_metadata_2025 huggingface dataset:
Pinpointing Mechanochemical Bond Rupture by Embedding the Mechanophore into a Macrocycle
Authors: Schütze Doreen , Holz Katharina , Müller Julian , Beyer Martin K. , Lüning Ulrich , Hartke Bernd
Published: January 2015

Mechanophores contain a mechanically labile bond that can be broken by an external mechanical force. Quantitative measurement and control of the applied force is possible through atomic force microscopy (AFM). A macrocycle was synthesized that contains both the mechanophore and an aliphatic chain that acts as a “safety line” upon bond breaking. This ring‐opening mechanophore unit is linked to poly(ethylene glycol) spacers, which allow investigation by single molecule force spectroscopy. The length increase upon rupture of the mechanophore was measured and compared with quantum chemical calculations.
Synthetic Membranes for Water Purification: Status and Future
Authors: Fane Anthony G. , Wang Rong , Hu Matthew X.
Published: January 2015

Membrane technology offers the best options to “drought proof” mankind on an increasingly thirsty planet by purifying seawater or used (waste) water. Although desalination by reverse osmosis (RO) and wastewater treatment by membrane bioreactors are well established the various membrane technologies still need to be significantly improved in terms of separation properties, energy demand and costs. We can now define the ideal characteristics of membranes and advances in material science and novel chemistries are leading to increasingly effective membranes. However developments in membranes must be matched by improved device design and membrane engineering. It is likely that limitations in fluid mechanics and mass transfer will define the upper bounds of membrane performance. Nevertheless major advances and growth over the next 20 years can be anticipated with RO remaining as the key to desalination and reclamation, with other membrane processes growing in support and in niche areas.
A Tailor‐Made Specific Anion‐Binding Motif in the Side Chain Transforms a Tetrapeptide into an Efficient Vector for Gene Delivery
Authors: Li Mao , Schlesiger Stefanie , Knauer Shirley K. , Schmuck Carsten
Published: January 2015

Arginine‐rich cell‐penetrating peptides are widely utilized as vectors for gene delivery. However, their transfection efficacy still needs to be optimized. To accomplish this, guanidinocarbonylpyrrole groups, which are tailor‐made anion binding sites, were introduced into the side chains of tetralysine to obtain the peptide analogue 1. In contrast to the common strategy of adding a lipophilic tail to peptide vectors, this novel method most likely enhances transfection efficacy through more specific interactions between the binding motifs and DNA or the cell membrane. Tetrapeptide analogue 1 is thus the smallest peptidic transfection vector that has been reported to date. The transfection efficacy of 1, which on average has less than two positive charges under physiological conditions, is even better than that of polyethylenimine (PEI). Furthermore, 1 exhibits only negligible cytotoxicity, which makes it an interesting candidate for further development.
Epoxidized poly(N‐isopropyl acrylamide)‐b‐epoHTPB‐b‐poly(N‐isopropyl acrylamide) triblock copolymer micelle nanoparticles for 10‐hydroxycamptothecin drug release
Authors: Luo Yan‐Ling , Zhang Jun , Han Fang‐Jie , Xu Feng , Chen Ya‐Shao , Liu Ru
Published: January 2015

Thermoresponsive poly(N‐isopropyl acrylamide) (PNIPAM)‐block‐hydroxy‐terminated polybutadine‐block‐PNIPAM triblock copolymers were synthesized by atom transfer radical polymerization; this was followed by the in situ epoxidation reaction of peracetic acid. The copolymers were characterized by 1H‐NMR, Fourier transform infrared spectroscopy, and size exclusion chromatography measurements, and their physicochemical properties in aqueous solution were investigated by surface tension measurement, fluorescent spectrometry, ultraviolet–visible transmittance, transmission electron microscopy observations, dynamic light scattering, and so on. The experimental results indicate that the epoxidized copolymer micelle aggregates retained a spherical core–shell micelle structure similar to the control sample. However, they possessed a decreased critical aggregate concentration (CAC), increased hydrodynamic diameters, and a high aggregation number and cloud point because of the incorporation of epoxy groups and so on. In particular, the epoxidized copolymer micelles assumed an improved loading capacity and entrapment efficiency of the drug, a preferable drug‐release profiles without an initial burst release, and a low cytotoxicity. Therefore, they were more suitable for the loading and delivery of the hydrophobic drug as a controlled release drug carrier. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41877.
Rheological properties, cure characteristics, and morphology of acrylonitrile‐based nanorubber modified epoxy
Authors: Ozdemir Nazli G. , Zhang Tao , Hadavinia Homayoun , Aspin Ian , Wang Jian
Published: January 2015

This article investigates the effects of nano carboxylic acrylonitrile butadiene rubber (CNBR‐NP) and nano acrylonitrile butadiene rubber (NBR‐NP) on the rheological properties and cure characteristics of epoxy. Dynamic mechanical behavior of carbon fiber reinforced polymer composites (CFRP) with the nanorubber‐modified matrices was also studied. Rheological study showed that NBR‐NP blends attained lower viscosity in comparison to CNBR‐NP blends and both systems exhibited shear‐thinning behavior. Scanning electron microscopy (SEM) images revealed that CNBR‐NP could be dispersed evenly within the epoxy matrix using industrial mixing process whereas partial agglomeration was observed in NBR‐NP blends. The dynamic mechanical analysis (DMA) data showed that the addition of nanorubber has negligible effect on the glass transition temperature of the epoxy. The difference in the dispersion ability of these two nanorubbers in epoxy is related to the difference in van der Waals forces between single nanoparticles, the chemical formula and the polarity of the systems. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41911.
Failure mechanism of polyamide 66 nanofiber yarns under fatigue and static tensile loading
Authors: Asghari Mooneghi Sara , Gharehaghaji Ali Akbar , Hosseini‐Toudeshky Hossein , Torkaman Giti
Published: January 2015

This work aims at fractography of polyamide 66 nanofiber yarns. The yarns are produced with three twist levels via electrospinning. In order to study the fracture modes of nanofiber yarns, fatigue, and static tensile tests including monotonic, low cycle fatigue, and postcyclic monotonic tensile tests are performed. It is observed that the catastrophic failure of yarns is associated with axial splitting in the three categories. The nanofibers within the yarn structure show a ductile fracture and buckle after tensile stress release. In comparison of postcyclic monotonic tensile tests with other categories, nanofibers show severe plastic buckling in response to release of the same applied force. Fractography studies reveal that twisting causes construction of a layered structure in the yarns which is similar to the ideal yarn structure as well. Applying cyclic loading causes the separation of these structural layers which is more considerable under higher number of cycles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41925.
Biocidal activity of cellulose materials for medical implants
Authors: Onofrei Mihaela Dorina , Dobos Adina Maria , Dunca Simona , Ioanid Emil Ghiocel , Ioan Silvia
Published: January 2015

Surface wettability trends, and blood component adhesion of some cellulose acetate phthalate/hydroxypropyl cellulose blend films are analyzed in view of adapting the system to biomedical applications. The results show that intermediate blend compositions of the corresponding films influence the surface tension parameters—controlled by the interactions occurring in the system. Increasing hydrophobicity and, implicitly, decreasing the polar surface tension components, are correlated with the adhesion/cohesion of blood components and plasma proteins. Thus, the work of spreading proteins on the hydrophobic blend surfaces indicated that albumin is not absorbed preferentially, while fibrinogen is characterized by a higher degree of adhesion on the surfaces, and also that selective adsorption of plasma proteins modifies blood compatibility. In addition, the obtained results and the ascertained antimicrobial activity of the studied blends contribute to the development of new applications in the biomedical field. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41932
Rapid determination of trace thiabendazole in apple juice utilizing dispersive liquid–liquid microextraction combined with fluorescence spectrophotometry
Authors: Li Wei , Wang Yuning , Huang Limin , Wu Ting , Hu Huilian , Du Yiping
Published: January 2015

Food safety has become a large concern and prompts an urgent need for the development of rapid, simple and sensitive analytical methods that can monitor pesticide residues in foods. This study aimed to provide a method for quantitative determination of trace thiabendazole in apple juice. Due to its high sensitivity and selectivity, fluorescence spectrophotometry was utilized as a front end to dispersive liquid–liquid microextraction (DLLME). The experimental parameters that influenced the extraction were systematically investigated. Under optimum conditions, the whole procedure, including DLLME and analysis of one sample, was carried out within 5 min, and linearity was found in the 5–50 µg/L range with a correlation coefficient (r) of 0.9987. The limit of detection value was 2.2 µg/L. Good reproducibility was achieved based with a less than 4.5% relative standard deviation (RSD) for five replicates at different sample concentrations. This method was shown to be suitable for rapid and sensitive quantification of thiabendazole in apple juice. Copyright © 2015 John Wiley & Sons, Ltd.
Arginine dipeptides affect insulin aggregation in a pH‐ and ionic strength‐dependent manner
Authors: Nuhu Mariam M. , Curtis Robin
Published: January 2015

Solutions containing arginine or mixtures of arginine and other amino acids are commonly used for protein liquid formulations to overcome problems such as high viscosities, aggregation, and phase separation. The aim of this work is to examine whether the stabilizing properties of arginine can be improved by incorporating the amino acid into a dipeptide. A series of arginine‐containing dipeptides have been tested for their ability to suppress insulin aggregation over a range of pH and ionic strength. The aggregation is monitored at room temperature using a combination of turbidimetry and light scattering for solutions at pH 5.5 or 3.7, whereas thermal‐induced aggregation is measured at pH 7.5. In addition, intrinsic fluorescence has been used to quantify additive binding to insulin. The dipeptide diArg is the most effective additive in solutions at pH 5.5 and 3.7, whereas the dipeptide Arg‐Phe almost completely eliminates thermally‐induced aggregation of insulin at pH 7.5 up to temperature of 90°C. Insulin has been chosen as a model system because the molecular forces controlling its aggregation are well known. From this understanding, we are able to provide a molecular basis for how the various dipeptides affect insulin aggregation.
A rapid and sensitive LC‐MS/MS method for quantification of 3,29‐dibenzoyl rarounitriol in rat plasma: application to a pharmacokinetic study
Authors: Zhao Chengliang , Zhang Nan , Chen Bin , Song Youxin , Zhu Naiqiang , Zhao Long , Liu Changjian , Meng Xiangwei
Published: January 2015

A rapid, sensitive and high‐throughput liquid chromatography–tandem mass spectrometry was established and validated to assay the concentrations of 3,29‐dibenzoyl rarounitriol in rat plasma. Plasma samples were processed by liquid–liquid extraction with ethyl acetate and separated on a Hypersil Gold C18 column (50 × 4.6 mm, 3 µm) at an isocratic flow rate of 0.5 mL/min using methanol–10 mm ammonium acetate–formic acid (90:10:0.1, v/v/v) as mobile phase. The total run time was 5 min for each sample. MS/MS detection was accomplished in selected reaction monitoring mode with positive electrospray ionization. The calibration curve was linear over the concentration range of 0.125–50 ng/mL with lower limit of quantification of 0.125 ng/mL. The intra‐ and inter‐day precisions were <10.1% in terms of coefficient of variation, and the accuracy was within ±11.7% in terms of relative error. The developed method was successfully applied to a pharmacokinetic study of 3,29‐dibenzoyl rarounitriol following intragastric administration of 3.65 mg/kg to Wistar rats. Copyright © 2015 John Wiley & Sons, Ltd.
Placenta accreta: adherent placenta due to Asherman syndrome
Authors: Engelbrechtsen Line , Langhoff‐Roos Jens , Kjer Jens Joergen , Istre Olav
Published: January 2015

Key Clinical Message

It is important to be aware of the risk of abnormally invasive placenta in patients with a history of Asherman syndrome and uterine scarring. A prenatal diagnosis by ultrasonography is useful when planning of mode of delivery.
Balancing the Stability–Activity Trade‐Off by Fine‐Tuning Dehalogenase Access Tunnels
Authors: Liskova Veronika , Bednar David , Prudnikova Tatyana , Rezacova Pavlina , Koudelakova Tana , Sebestova Eva , Smatanova Ivana Kuta , Brezovsky Jan , Chaloupkova Radka , Damborsky Jiri
Published: January 2015

A variant of the haloalkane dehalogenase DhaA with greatly enhanced stability and tolerance of organic solvents but reduced activity was created by mutating four residues in the access tunnel. To create a stabilised enzyme with superior catalytic activity, two of the four originally modified residues were randomised. The resulting mutant F 176 G exhibited 32‐ and 10‐times enhanced activity towards 1,2‐dibromoethane in buffer and 40 % DMSO, respectively, upon retaining high stability. Structural and molecular dynamics analyses demonstrated that the new variant exhibited superior activity because the F 176 G mutation increased the radius of the tunnel’s mouth and the mobility of α‐helices lining the tunnel. The new variant’s tunnel was open in 48 % of trajectories, compared to 58 % for the wild‐type, but only 0.02 % for the original four‐point variant. Delicate balance between activity and stability of enzymes can be manipulated by fine‐tuning the diameter and dynamics of their access tunnels.
Characterization and Reactivity of a Terminal Nickel(III)–Oxygen Adduct
Authors: Pirovano Paolo , Farquhar Erik R. , Swart Marcel , Fitzpatrick Anthony J. , Morgan Grace G. , McDonald Aidan R.
Published: January 2015

High‐valent terminal metal–oxygen adducts are hypothesized to be the potent oxidizing reactants in late transition metal oxidation catalysis. In particular, examples of high‐valent terminal nickel–oxygen adducts are scarce, meaning there is a dearth in the understanding of such oxidants. A monoanionic NiII‐bicarbonate complex has been found to react in a 1:1 ratio with the one‐electron oxidant tris(4‐bromophenyl)ammoniumyl hexachloroantimonate, yielding a thermally unstable intermediate in high yield (ca. 95 %). Electronic absorption, electronic paramagnetic resonance, and X‐ray absorption spectroscopies and density functional theory calculations confirm its description as a low‐spin (S=1/2), square planar NiIII–oxygen adduct. This rare example of a high‐valent terminal nickel–oxygen complex performs oxidations of organic substrates, including 2,6‐di‐tert‐butylphenol and triphenylphosphine, which are indicative of hydrogen atom abstraction and oxygen atom transfer reactivity, respectively.
Multilayer organic deposition on the rock surface with different wettabilities during solvent injection for heavy‐oil recovery
Authors: Moreno Laura , Babadagli Tayfun
Published: January 2015

During solvent‐based heavy‐oil and bitumen recovery processes, viscosity reduction occurs through dilution of oil by mixing process. However, asphaltene precipitation may take place, eventually resulting in organic deposition (maltenes and asphaltenes) in the reservoir causing a reduction in permeability through pore plugging and unfavourable wettability reversal. In this paper, two identical porous media (unconsolidated glass bead packs) with significant contrast in wettability were used to investigate these phenomena. The oil‐wet and water‐wet glass bead models were exposed to constant rate solvent injection (propane, n‐hexane, n‐decane, and distillate hydrocarbon). The thickness of the multilayer organic deposition was determined using focused ion beam (FIB/SEM) and scanning electron microscope (SEM). Three points from the models were analyzed to determine the level of asphaltene deposition and oil trapping (maltenes) on the surface of the glass beads and pore spaces. The results showed that the asphaltene migrated through the glass bead pack model. As a consequence, asphaltene deposition was observed at the middle and bottom points of the vertically situated glass bead packs with an injection point at the top, in addition to accumulated oil trapping at the production (bottom) end. Moreover, elemental mapping from the organic deposition visualization was conducted using the energy dispersive X‐ray (EDX) analysis. Heteroatom elements were found in the sample along with carbon and iron elements.
Characterization of bismuth germanate crystals grown by EFG method
Authors: Galenin Evgeny , Baumer Vyacheslav , Gerasymov Iaroslav , Tkachenko Sergii , Sidletskiy Oleg
Published: January 2015

Bismuth germanate shaped crystals have been grown by the EFG (Stepanov) method. The correlation between growth rate, shape of crystals, their optical and scintillation parameters has been analysed. Optical and scintillation characteristics of the EFG crystals are similar to those obtained with Czochralski grown crystals, however, growth rate in EFG is by 2.5 times larger. Also we compare the photochromic effect under UV‐irradiation in EFG and Czochralski grown crystals. Material losses at fabrication of plates, pixels, and rods from EFG shaped plates may be reduced by ∼50% compared to large diameter boules.
Photocatalytic Carbon Dioxide Reduction with Rhodium‐based Catalysts in Solution and Heterogenized within Metal–Organic Frameworks
Authors: Chambers Matthew B. , Wang Xia , Elgrishi Noémie , Hendon Christopher H. , Walsh Aron , Bonnefoy Jonathan , Canivet Jérôme , Quadrelli Elsje Alessandra , Farrusseng David , Mellot‐Draznieks Caroline , Fontecave Marc
Published: January 2015

The first photosensitization of a rhodium‐based catalytic system for CO2 reduction is reported, with formate as the sole carbon‐containing product. Formate has wide industrial applications and is seen as valuable within fuel cell technologies as well as an interesting H2‐storage compound. Heterogenization of molecular rhodium catalysts is accomplished via the synthesis, post‐synthetic linker exchange, and characterization of a new metal–organic framework (MOF) Cp*Rh@UiO‐67. While the catalytic activities of the homogeneous and heterogeneous systems are found to be comparable, the MOF‐based system is more stable and selective. Furthermore it can be recycled without loss of activity. For formate production, an optimal catalyst loading of ∼10 % molar Rh incorporation is determined. Increased incorporation of rhodium catalyst favors thermal decomposition of formate into H2. There is no precedent for a MOF catalyzing the latter reaction so far.
Metabolic syndrome: an ill wind that blows some good?
Authors: Taylor Simeon I.
Published: January 2015

In this issue of the journal, Brima et al. report thought‐provoking research providing a potential evolutionary rationale whereby natural selection might have preserved genes that predispose to metabolic syndrome. When CD‐1 mice were fed a high fat diet, this induced metabolic changes characteristic of metabolic syndrome. In addition, the high fat diet provided substantial protection from lethality due to infection with Trypanosoma cruzi. The authors hypothesize that the same genes predispose to both metabolic syndrome and protection against infectious disease. Thus, the selective advantage of not dying from infectious disease implicitly provides selective pressure predisposing to metabolic syndrome. This hypothesis follows a similar line of reasoning that has provided explanations for the survival of the HbS mutation for sickle cell disease and renal disease‐associated genetic variants in apolipoprotein L1. Variants in these two genes provide protection from malaria and Trypanosoma brucei rhodesiense, respectively. Copyright © 2015 John Wiley & Sons, Ltd.
The development of decision limits for the GH‐2000 detection methodology using additional insulin‐like growth factor‐I and amino‐terminal pro‐peptide of type III collagen assays
Authors: Holt Richard I. G. , Böhning Walailuck , Guha Nishan , Bartlett Christiaan , Cowan David A. , Giraud Sylvain , Bassett E. Eryl , Sönksen Peter H. , Böhning Dankmar
Published: January 2015

The GH‐2000 and GH‐2004 projects have developed a method for detecting GH misuse based on measuring insulin‐like growth factor‐I (IGF‐I) and the amino‐terminal pro‐peptide of type III collagen (P‐III‐NP). The objectives were to analyze more samples from elite athletes to improve the reliability of the decision limit estimates, to evaluate whether the existing decision limits needed revision, and to validate further non‐radioisotopic assays for these markers. The study included 998 male and 931 female elite athletes. Blood samples were collected according to World Anti‐Doping Agency (WADA) guidelines at various sporting events including the 2011 International Association of Athletics Federations (IAAF) World Athletics Championships in Daegu, South Korea. IGF‐I was measured by the Immunotech A15729 IGF‐I IRMA, the Immunodiagnostic Systems iSYS IGF‐I assay and a recently developed mass spectrometry (LC‐MS/MS) method. P‐III‐NP was measured by the Cisbio RIA‐gnost P‐III‐P, Orion UniQ™ PIIINP RIA and Siemens ADVIA Centaur P‐III‐NP assays. The GH‐2000 score decision limits were developed using existing statistical techniques. Decision limits were determined using a specificity of 99.99% and an allowance for uncertainty because of the finite sample size. The revised Immunotech IGF‐I – Orion P‐III‐NP assay combination decision limit did not change significantly following the addition of the new samples. The new decision limits are applied to currently available non‐radioisotopic assays to measure IGF‐I and P‐III‐NP in elite athletes, which should allow wider flexibility to implement the GH‐2000 marker test for GH misuse while providing some resilience against manufacturer withdrawal or change of assays. Copyright © 2015 John Wiley & Sons, Ltd.
Six1 is down‐regulated in end‐stage human dilated cardiomyopathy independently of Ezh2
Authors: Tschirner Anika , Palus Sandra , Hetzer Roland , Meyer Rudolf , Anker Stefan D. , Springer Jochen
Published: January 2015

Background

Recently, it was shown that a knock‐out (KO) of the polycomb histone methyltransferase Ezh2 leads to cardiac hypertrophy in mice, which was driven by the homeodomain transcription factor Six1. Here, we analyzed the expression of Six1 and its regulating factor Ezh2 in cardiac tissue of patients with end‐stage dilative cardiomyopathy (DCM).

Methods

Tissue samples of patients with end‐stage DCM (n = 35) were compared with controls (n = 12) for the protein expression of Ezh1, Ezh2, Six1, and a marker of protein expression p70S6K.

Results

Contrary to the Ezh2‐KO mouse model, we found a down‐regulation of Six1 (26%) and an up‐regulation of Ezh2 (76%) in DCM hearts, (both P < 0.05). Expression of Ezh2 and Six1 did not correlate in human tissue (DCM: r2: 0.03, P = 0.31 and donor: r2: 0.05, P = 0.45). Expression of Six1 weakly correlated with left ventricular end‐systolic diameter and fractional shortening. In DCM, Six1 also showed a positive correlation to the expression of the ribosomal protein p70S6K (r: 0.39, P = 0.029), which is involved in protein synthesis. This correlation was not seen in donor tissue, which showed a trend for a negative correlation (r: −0.49, P = 0.08).

Conclusion

Our data indicate that the Ezh2/Six1 axis might be involved in human DCM. However, Six1 expression may be regulated by factors other than Ezh2, and more research is needed to determine the precise role of Ezh2/Six1 in human DCM.
A Series of Noncentrosymmetric Antimony Sulfides Ln8Sb2S15 (Ln = La, Pr, Nd) – Syntheses, Crystal and Electronic Structures, and NLO Properties
Authors: Zhao Hua‐Jun , Zhou Liu‐Jiang
Published: January 2015

A series of noncentrosymmetric sulfides Ln8Sb2S15 (Ln = La, Pr, Nd) were prepared from stoichiometric mixtures of the elements at 1223 K in an evacuated silica tube. The compounds Ln8Sb2S15 with Ln = La and Nd are isostructural to Pr8Sb2S15 and crystallize in the tetragonal noncentrosymmetric space group I41cd. Their structure contains discrete [SbS3]3– trigonal pyramids separated by Ln3+ cations and S2– anions. La8Sb2S15 shows second harmonic generation with intensities 1.2 times that of the commercially used IR NLO (nonlinear optics) material AgGaS2 (at 2.05 μm laser). It exhibits excellent thermal stability up to 663 °C. Studies with UV/Vis–NIR diffuse reflectance spectroscopy show that La8Sb2S15 has an optical gap of around 2.3 eV, and a DFT study indicates a direct band gap with an electronic transfer excitation of S 3p electrons to a La 5d orbital.
Seleno‐methionine decreases biohydrogenation of C18 unsaturated fatty acids in ovine ruminal fluid incubated in vitro with α‐linolenic acid
Authors: Czauderna Marian , Rozbicka‐Wieczorek Agnieszka J. , Więsyk Edyta , Krajewska‐Bienias Katarzyna A.
Published: January 2015

The influence of seleno‐methionine (Se‐Met) added to an ovine ruminal fluid containing α‐linolenic acid (α‐LNA) on the profile of fatty acids (FA) was investigated. The fluid was incubated in vitro at 39°C under CO2 either alone (the control ruminal fluid; RF) or with α‐LNA (1.67 mg/mL) or with a combination of α‐LNA with either a low (1.25 µg/mL) or high (4.16 µg/mL) concentration of Se as Se‐Met. Tubes with fluids were removed after 0, 6, 12, 18 or 24 h of incubation. α‐LNA in the fluids with/without Se‐Met stimulated the accumulation of C14:0 and C16:0 compared with the RF. The fluids containing Se‐Met reduced the concentration of C18:0 compared with the RF. α‐LNA in the fluids with/without Se‐Met increased concentrations of cis9C14:1, cis9C18:1 and trans11C18:1 compared with the RF and the fluids with Se‐Met. The fluids with α‐LNA and Se‐Met increased the accumulation of trans9trans11cis15C18:3 compared with the fluids with α‐LNA. The fluids with α‐LNA and Se‐Met decreased the biohydrogenation to C18:0 compared with the RF. Se‐Met in the fluids elevated the concentration of trans11C18:1 and lowered the capacity of the biohydrogenation to C18:0 in the fluids incubated for 24 h. Added Se‐Met affected the FA profile in incubated fluids.

Practical applications

Selenium and polyunsaturated fatty acids n‐3 (PUFAn‐3) are very important for human health and nutrition. Recent studies documented that a higher content of mono‐conjugated isomers of α‐linolenic acid (α‐LNA) in diets reduced the abundance of PUFAn‐3 in the brain, liver and heart of experimental animals. Due to the increasing world population, overfishing of the seas and usually low concentrations of PUFAn‐3 and essential trace elements (like selenium) in animal products, there is a demand for better methods of feeding livestock. Considering the above, it was desirable to study the extent to which dietary seleno‐compounds (like seleno‐methionine) may contribute to concentrations of mono‐conjugated α‐LNA (C‐α‐LNA) isomers, as C‐α‐LNA isomers may perturb the PUFA balance (or imbalance) in tissues of animals and humans. Moreover, further studies are needed to determine if dietary seleno‐compounds, α‐LNA and C‐α‐LNA isomers also induce changes in concentrations of fatty acids, especially PUFAn‐3, in tissues of lambs.

Seleno‐methionine has an influence on the concentrations of fatty acids, especially unsaturated fatty acids, in in vitro incubated ovine ruminal fluid, irrespective of the presence of α‐linolenic acid. Seleno‐methionine added to the incubated fluids affects the capacity of the bacterial isomerases and modified activities of ruminal bacteria. The simultaneous addition of α‐linolenic acid and Se‐Met to the ruminal fluids decreased the yield of final biohydrogenation to C18:0 in comparison with the in vitro incubated control fluids.
Iron‐catalyzed depolymerizations of silicones with hexanoic anhydride provide a potential recycling method for end‐of‐life polymers
Authors: Weidauer Maik , Heyder Benedict , Woelki Daniel , Tschiersch Moritz , Köhler‐Krützfeldt Angela , Enthaler Stephan
Published: January 2015

One of the great impacts of polymeric materials is the matter of the accumulation of huge amounts of end‐of‐life polymers. At the present date, waste management is based primarily on landfills, thermal recycling, and down‐cycling, while only a small part of the waste is subjected to feedstock recycling. In more detail, polymers are converted to low‐molecular weight synthons by depolymerization and a subsequent polymerization process creates new high‐quality polymers. Widely‐used polymers in modern society are polysiloxanes (silicones) and recycling is still an issue. In this regard, we present herein the depolymerization of polysiloxanes, applying a fatty acid anhydride as the depolymerization reagent. In the presence of catalytic amounts of iron salts, low‐molecular weight products with the motif RC(O)(OSiMe2)mOC(O)R (R = n‐pentyl, m = 1–4) were observed. Notably, the reaction of RC(O)(OSiMe2)mOC(O)R with water revealed the formation of octamethylcyclotetra‐ and decamethylcyclopentasiloxanes and the corresponding fatty acid as side product, which can potentially be reconverted to the fatty acid anhydride. Interestingly, a recycling of the polymer and the depolymerization reagent is feasible.

Practical applications: Huge amounts of end‐of‐life polymers are produced by our society and several methodologies for waste treatment have been established so far. One interesting recycling approach can be the conversion of end‐of‐life polymers, via depolymerization, into useful commodities, which can be applied as feedstock for new materials. Taking these aspects into account we studied the depolymerization of end‐of‐life polysiloxanes, applying cheap and abundant iron salts as a precatalyst and a fatty acid anhydride as a depolymerization reagent, which can be easily accessed from renewable resources, hence avoiding the use of fossil fuels‐based chemicals. As major products RC(O)(OSiMe2)mOC(O)R were obtained, these can be utilized as starting material for new polysiloxanes. Moreover, the simple operation of the reaction (e.g., no protection atmosphere, solvent free) makes this recycling method attractive for large scale applications.

In the present work, the straightforward iron‐catalyzed depolymerization of end‐of‐life polysiloxanes with a fatty acid anhydride has been studied. Depolymerization products RC(O)O(SiMe2)mOC(O)R have been produced, which can be appropriate starting materials for new polymers.
Unprotected Xylose‐Derived Nitrone in Stereodivergent Synthesis of 4‐Hydroxypiperidine Enantiomers: Weak Lewis Acid Induced Alteration of Stereochemistry in 1,3‐Dipolar Cycloaddition
Authors: Rowicki Tomasz , Malinowski Maciej , Gryszel Maciej , Czerwińska Karolina , Madura Izabela , Mironiuk‐Puchalska Ewa , Koszytkowska‐Stawińska Mariola , Sas Wojciech
Published: January 2015

A one‐pot, two‐step synthesis of chiral 7‐oxa‐1‐azabicyclo[2.2.1]heptane derivatives from unprotected D‐xylose was achieved by an intramolecular 1,3‐dipolar cycloaddition of the N‐(γ‐alkenyl)‐substituted nitrone intermediate. The stereochemical course of the cycloaddition was altered by the addition of an achiral Lewis acid. The bicyclic byproducts were employed in a concise synthesis of two new enantiomeric piperidine‐type iminosugars.
4,4,8,8‐Tetranitroadamantane‐2,6‐diyl Dinitrate: A High‐Density Energetic Material
Authors: Ling Yifei , Ren Xiaoli , Lai Weipeng , Luo Jun
Published: January 2015

The novel high‐performance energetic material 4,4,8,8‐tetranitroadamantane‐2,6‐diyl dinitrate has been synthesized and fully characterized. The synthetic strategy features the construction of the adamantane skeleton with different functional groups at adjacent methylene carbon atoms to overcome the problems associated with the ortho effect and steric crowding, and is amenable to the synthesis of other polynitroadamantanes. The experimentally determined physical properties as well as the calculated detonation properties indicate that this compound exhibits high thermal stability (220 °C), high density (1.852 g cm–3), and excellent detonation velocities (8529 m s–1) and pressures (33.43 GPa).
Enzymatic Oxygen Microsensor Based on Bilirubin Oxidase Applied to Microbial Fuel Cells Analysis
Authors: Grattieri Matteo , Babanova Sofia , Santoro Carlo , Guerrini Edoardo , Trasatti Stefano PM , Cristiani Pierangela , Bestetti Massimiliano , Atanassov Plamen
Published: January 2015

A selective oxygen biosensor based on bilirubin oxidase (BOx) was developed. The sensor was used for determining oxygen profiles in a membraneless, single‐chamber microbial fuel cell (SCMFC), fed with raw wastewater. The linear response of the sensor was optimized by a diffusion layer of silica gel. A computer‐controlled stage was used to obtain accurate and precise measurements. Oxygen concentration in biofilms covering electrodes was measured, showing 3 mg L−1 of O2 in the bulk solution, decreasing to 0 mg L−1 in the cathodic biofilm. The MFC generated power in the range of 0–0.08 mW, associated to the oxygen content.
Metabolic and molecular responses to leucine‐enriched branched chain amino acid supplementation in the skeletal muscle of alcoholic cirrhosis
Authors: Tsien Cynthia , Davuluri Gangarao , Singh Dharmvir , Allawy Allawy , Ten Have Gabriella A.M. , Thapaliya Samjhana , Schulze John M. , Barnes David , McCullough Arthur J. , Engelen Marielle P.K.J. , Deutz Nicolaas E.P. , Dasarathy Srinivasan
Published: January 2015

Skeletal muscle loss (sarcopenia) is a major clinical complication in alcoholic cirrhosis with no effective therapy. Skeletal muscle autophagic proteolysis and myostatin expression (inhibitor of protein synthesis) are increased in cirrhosis and believed to contribute to anabolic resistance. A prospective study was performed to determine the mechanisms of sarcopenia in alcoholic cirrhosis and potential reversal by leucine. In six well‐compensated, stable, alcoholic patients with cirrhosis and eight controls, serial vastus lateralis muscle biopsies were obtained before and 7 hours after a single oral branched chain amino acid mixture enriched with leucine (BCAA/LEU). Primed‐constant infusion of l‐[ring‐2H5]‐phenylalanine was used to quantify whole‐body protein breakdown and muscle protein fractional synthesis rate using liquid chromatography/mass spectrometry. Muscle expression of myostatin, mammalian target of rapamycin (mTOR) targets, autophagy markers, protein ubiquitination, and the intracellular amino acid deficiency sensor general control of nutrition 2 were quantified by immunoblots and the leucine exchanger (SLC7A5) and glutamine transporter (SLC38A2), by real‐time polymerase chain reaction. Following oral administration, plasma BCAA concentrations showed a similar increase in patients with cirrhosis and controls. Skeletal muscle fractional synthesis rate was 9.63 ± 0.36%/hour in controls and 9.05 ± 0.68%/hour in patients with cirrhosis (P = 0.54). Elevated whole‐body protein breakdown in patients with cirrhosis was reduced with BCAA/LEU (P = 0.01). Fasting skeletal muscle molecular markers showed increased myostatin expression, impaired mTOR signaling, and increased autophagy in patients with cirrhosis compared to controls (P < 0.01). The BCAA/LEU supplement did not alter myostatin expression, but mTOR signaling, autophagy measures, and general control of nutrition 2 activation were consistently reversed in cirrhotic muscle (P < 0.01). Expression of SLC7A5 was higher in the basal state in patients with cirrhosis than controls (P < 0.05) but increased with BCAA/LEU only in controls (P < 0.001). Conclusions: Impaired mTOR1 signaling and increased autophagy in skeletal muscle of patients with alcoholic cirrhosis is acutely reversed by BCAA/LEU. (Hepatology 2015;61:2018‐2029)
Toxicity of cobalt–chromium nanoparticles released from a resurfacing hip implant and cobalt ions on primary human lymphocytes in vitro
Authors: Posada Olga M. , Tate R. J. , Grant M. H.
Published: January 2015

Adverse tissue responses to prostheses wear particles and released ions are important contributors to hip implant failure. In implant‐related adverse reactions T‐lymphocytes play a prominent role in sustaining the chronic inflammatory response. To further understand the involvement of lymphocytes in metal‐on‐metal (MoM) implant failure, primary human lymphocytes were isolated and treated with cobalt–chromium (Co‐Cr) wear debris and Co ions, individually, and in combination, for 24, 48 and 120 h. There was a significant increase in cell number where debris was present, as measured by the Neutral Red assay. Interleukin‐6 (IL‐6), interferon‐γ (IFN‐γ) and tumour necrosis factor‐α (TNF‐α) secretion levels significantly decreased in the presence of metal particles, as measured by ELISA. Interleukin‐2 (IL‐2) secretion levels were significantly decreased by both debris and Co ions. Flow cytometry analysis showed that the metal nanoparticles induced a significant increase in apoptosis after 48‐h exposure. This investigation showed that prolonged exposure (120 h) to metal debris induces lymphocyte proliferation, suggesting that activation of resting lymphocytes may have occurred. Although cytokine production was affected mainly by metal debris, cobalt toxicity may also modulate IL‐2 secretion, and even Co ion concentrations below the MHRA guideline levels (7 ppb) may contribute to the impairment of immune regulation in vivo in patients with MoM implants. Copyright © 2015 John Wiley & Sons, Ltd.
Investigating the neuroglial differentiation effect of neuroblastoma conditioned medium in human endometrial stem cells cultured on 3D nanofibrous scaffold
Authors: Ebrahimi‐Barough Somayeh , Hoveizi Elham , Norouzi Javidan Abbas , Ai Jafar
Published: January 2015

Neural tissue engineering is an important area of research in the field of tissue‐engineering especially for neurodegenerative disease such as spinal cord injury. The differentiation capacity of human endometrial stem cells (hEnSCs) into neuronal cells has yet to be elucidated. Here, the major aim of the present study was to investigate the differentiation ability of hEnSCs cultured on polylactic acid/chitosan (PLA/CS) nanofibrous scaffold into neuroglial cells in response to conditioned medium of BE(2)‐C human neuroblastoma cells and growth factors. Here we investigated the use PLA/CS scaffold as a three dimensional (3D) system that increased neuro‐glial cells differentiation. Human EnSCs after three passages were differentiated in neuro‐glial like cells under neuroblastoma conditioned medium with FGF2/PDGF‐AA on PLA/CS scaffold. By day 18, differentiated cells were analyzed for expression of neuroglial markers by qRT‐PCR and immunofluorescence. The results revealed that hEnSCs attach, grow and differentiation on the nanofibrous PLA/CS scaffold. Additionally, our study showed the expression of neural and glial lineage markers such as Nestin, NF‐L, MAP2, PDGFRa, CNP, Olig2, MBP, and GFAP in the level of mRNA and MAP2, Tuj‐1, and NF‐L in the protein level after 18 days. Our results demonstrate that hEnSCs cultured on PLA/CS nanofibrous scaffold have the potential to differentiate in neuronal and glial cells in presence of neuroblastoma conditioned medium on PLA/CS scaffold. The result of this study may have impact in tissue engineering and cells‐base therapy of neurodegenerative diseases and have a great potential for wide application. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 2621–2627, 2015.
Spatial and temporal temperature trends in the lower stratosphere during the extended boreal winter from reanalyses
Authors: Lopez‐Bustins Joan A. , Serrano Encarna , Ayarzagüena Blanca , Sanchez‐Lorenzo Arturo
Published: January 2015

Temperature anomalies in the lower stratosphere (namely, at 50‐hPa) poleward of 30°N (hereafter, T50) are analysed from reanalysis daily products (i.e. ERA‐40 and NCEP/NCAR) in order to detect those regions with statistically significant trends of T50 during the common 1957–2002 period. We also analyse radiosonde data in order to validate the reanalyses results. The analyses are conducted for the extended polar winter (i.e. from November to May) in order to relate T50 changes to the northern polar vortex variability. In relation to the previous literature, the novelty of this study is double: first, temporal evolution is considered according to regions with similar T50 temporal variability in the Northern Hemisphere; second, trend analyses of stratospheric temperatures are obtained with the use of running windows with variable width of each principal component series computed from monthly mean values. Two main stratospheric regions were identified from both reanalyses, with a statistically significant cooling within the study period: one over the high latitudes and a second one tracing a subtropical ring. The first one was detected in November, December and May during several decades, particularly at the beginning and in the middle of the study period (i.e. 1957–1985). The second region (i.e. the subtropical ring) showed overall cooling for all months along the study period. In addition, the lower stratospheric temperature over northern Europe exhibited an outstanding cooling in May for the whole study period. The results obtained from both reanalyses are practically identical, a fact that provides robustness thereto. Radiosonde data confirm the above‐mentioned results, but the magnitude of the trends given by reanalysis products is substantially overestimated in the winter months over high latitudes.
Spatiotemporal distribution of thunderstorm initiation in the US Great Plains from 2005 to 2007
Authors: Lock Noah A. , Houston Adam L.
Published: January 2015

A first‐of‐its‐kind automated thunderstorm tracking algorithm that relies on radar reflectivity data and cloud‐to‐ground lighting is used to identify the spatiotemporal distribution of thunderstorm initiation over the central United States for 2005–2007. Nearly 56 000 thunderstorm initiations are identified. High concentrations of thunderstorm initiation are found near prominent topography and near the Gulf coast. The annual distribution exhibits a peak in August and the diurnal cycle exhibits a peak at the local solar noon with the majority of initiations occurring between 2 h prior to and 6 h past the local solar noon. While the results are largely expected, no previous study has documented the distribution of thunderstorm initiation over the geographic extent and period of record used to develop the results presented here.
Effect of oxidant stressors and phenolic antioxidants on the ochratoxigenic fungus Aspergillus carbonarius
Authors: Crespo‐Sempere Ana , Selma‐Lázaro Cristina , Palumbo Jeffrey D , González‐Candelas Luis , Martínez‐Culebras Pedro V
Published: January 2015

BACKGROUND

There are few studies dealing with the relationship between oxidative stress and ochratoxin A (OTA) biosynthesis. In this work, we analyzed the effect of the oxidant stressor menadione and the antioxidants 3,5‐di‐tert‐butyl‐4‐hydroxytoluene (BHT), catechin, resveratrol and a polyphenolic extract on growth, generation of reactive oxygen species (ROS), OTA production and gene expression of antioxidant enzymes of Aspergillus carbonarius.

RESULTS

Exposure to menadione concentrations higher than 20 µmol L−1 led to increases in ROS and OTA levels and a decrease in growth rate. Exposure to 2.5–10 mmol L−1 BHT also led to higher ROS and OTA levels, although growth rate was only affected above 5 mmol L−1. Naturally occurring concentrations of catechin, resveratrol and polyphenolic extract barely affected growth rate, but they produced widely different effects on OTA production level depending on the antioxidant concentration used. In general, gene expression of antioxidant enzymes superoxide dismutase (SOD) and peroxiredoxin (PRX) was downregulated after exposure to oxidant and antioxidant concentrations that enhanced OTA production level.

CONCLUSION

Aspergillus carbonarius responds to oxidative stress, increasing OTA production. Nevertheless, the use of naturally occurring concentrations of antioxidant phenolic compounds to reduce oxidative stress is not a valid approach by itself for OTA contamination control in grapes. © 2015 Society of Chemical Industry
Fiber‐Like Micelles from the Crystallization‐Driven Self‐Assembly of Poly(3‐heptylselenophene)‐block‐Polystyrene
Authors: Kynaston Emily L. , Gould Oliver E. C. , Gwyther Jessica , Whittell George R. , Winnik Mitchell A. , Manners Ian
Published: January 2015

The crystallization‐driven self‐assembly (CDSA) of crystalline‐coil polyselenophene diblock copolymers represents a facile approach to nanofibers with distinct optoelectronic properties relative to those of their polythiophene analogs. The synthesis of an asymmetric diblock copolymer with a crystallizable, π‐conjugated poly(3‐heptylselenophene) (P3C7Se) block and an amorphous polystyrene (PS) coblock is described. CDSA was performed in solvents selective for the PS block. Based on transmission electron microscopy (TEM) analysis, P3C7Se18‐b‐PS125 formed very long (up to 5 μm), highly aggregated nanofibers in n‐butyl acetate (nBuOAc) whereas shorter (ca. 500 nm) micelles of low polydispersity were obtained in cyclohexane. The micelle core widths in both solvents determined from TEM analysis (≈ 8 nm) were commensurate with fully‐extended P3C7Se18 chains (estimated length = 7.1 nm). Atomic force microscopy (AFM) analysis provided characterization of the micelle cross‐section including the PS corona (overall micelle width ≈ 60 nm). The crystallinity of the micelle cores was probed by UV–vis and photoluminescence (PL) spectroscopy and wide‐angle X‐ray scattering (WAXS).
Blueberries improve glucose tolerance without altering body composition in obese postmenopausal mice
Authors: Elks Carrie M. , Terrebonne Jennifer D. , Ingram Donald K. , Stephens Jacqueline M.
Published: January 2015

Objective

Metabolic syndrome (MetS) risk increases significantly during menopause and remains elevated postmenopause. Several botanicals, including blueberries (BB), have been shown to delay MetS progression, but few studies have been conducted in postmenopausal animal models. Here, the effects of BB supplementation on obese postmenopausal mice using a chemically induced menopause model were examined.

Methods

After induction of menopause, mice were fed a high‐fat diet or the same diet supplemented with 4% BB powder for 12 weeks. Body weight and body composition were measured, and mice were subjected to glucose and insulin tolerance tests. Serum triglycerides and adiponectin were measured, and liver histology and hepatic gene expression were assessed.

Results

Menopausal and BB‐supplemented mice had significantly higher body weights and fat mass than control mice, while menopausal mice had impaired glucose tolerance and higher serum triglycerides when compared with control and BB‐supplemented mice. Menopausal mice also had hepatic steatosis that was prevented by BB supplementation and correlated with expression of genes involved in hepatic fatty acid oxidation.

Conclusions

BB supplementation prevents the glucose intolerance and hepatic steatosis that occur in obese postmenopausal mice, and these effects are independent of body weight.