bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant biofarming: Novel insights for peptide expression in heterologous systems
Authors: Barbosa Viana Antônio Américo , Pelegrini Patrícia Barbosa , Grossi‐de‐Sá Maria Fátima 
Published: May 2012

AbstractPeptide expression methods have been widely studied and developed from many different biological sources. The cultivation of prokaryotic and eukaryotic cells has proven to be efficient for the expression of foreign peptides in several heterologous systems, including bacteria, insects, yeasts, and mammals. Earlier reports brought up new insights for the improvement of expressed products to not only increase the production rate of desired peptides but also reproduce desirable post‐translational modifications and even to reduce the risk of allergenicity when those products are aimed for human use. The development of bioreactor systems provided the optimization of cell growth conditions to scale up the amounts of expressed peptides. On the other hand, different cell systems and mutants provided a plethora of possible peptide modifications. Hence, in this report, we describe the many organisms and systems used for the large scale production of several macromolecules with relevance in health and agriculture. We also bring into discussion plant biofarming in the moss Physcomitrella patens and its recent adaptations, as a cost‐effective and efficient approach in the production of more complex heterologous proteins, given the fact that its glycosylation pattern can be engineered to avoid allergenicity to humans (common to plant‐derived glycoproteins). © 2012 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 416‐427, 2012.
Formation of Hierarchical Pore Structures in Zn/ZSM‐5 to Improve the Catalyst Stability in the Aromatization of Branched Olefins
Authors: Kim Yeon Ho , Lee Kyung Hee , Nam Chang‐Mo , Lee Jae Sung 
Published: May 2012

AbstractThree Zn/ZSM‐5 catalysts with Si/Al ratios of 17, 33, and 42 were treated with a weak base (Na2CO3) to create a hierarchical microporous–mesoporous system and to improve the catalyst stability in the aromatization of 2‐methly‐2‐butene, a model compound that represented branched olefin byproducts that are produced from fluidized catalytic cracking. The Si/Al ratio of the parent ZSM‐5 had a critical effect on the nature of the modified pore system. Thus, for Zn/ZSM‐5 with a Si/Al ratio of 42, a hierarchical microporous–mesoporous system was formed in which intraparticle bimodal mesopores were in the form of cavities and cylinders, the latter of which connected internal micropores to the external surface of the catalyst. This pore structure was most suitable for enhancing the tolerance to coking and brought a dramatic increase in the catalyst stability in the aromatization of 2‐methyl‐2‐butene.
Insights into the Mechanism of Reaction of [(C5Me5)2SmII(thf)2] with CO2 and COS by DFT Studies
Authors: Castro Ludovic , Labouille Stéphanie , Kindra Doug R. , Ziller Joseph W. , Nief Francois , Evans William J. , Maron Laurent 
Published: May 2012

AbstractReaction mechanisms for the oxidative reactions of CO2 and COS with [(C5Me5)2Sm] have been investigated by means of DFT methods. The experimental formation of oxalate and dithiocarbonate complexes is explained. Their formation involve the samarium(III) bimetallic complexes [(C5Me5)2Sm‐CO2‐Sm(C5Me5)2] and [(C5Me5)2Sm‐COS‐Sm(C5Me5)2] as intermediates, respectively, ruling out radical coupling for the formation of the oxalate complex.
Mechanism of the Tyrosine Ammonia Lyase Reaction—Tandem Nucleophilic and Electrophilic Enhancement by a Proton Transfer
Authors: Pilbák Sarolta , Farkas Ödön , Poppe László 
Published: May 2012

AbstractQuantum mechanics/molecular mechanics calculations in tyrosine ammonia lyase (TAL) ruled out the hypothetical Friedel–Crafts (FC) route for ammonia elimination from L‐tyrosine due to the high energy of FC intermediates. The calculated pathway from the zwitterionic L‐tyrosine‐binding state (0.0 kcal mol−1) to the product‐binding state ((E)‐coumarate+H2NMIO; −24.0 kcal mol−1; MIO=3,5‐dihydro‐5‐methylidene‐4H‐imidazol‐4‐one) involves an intermediate (IS, −19.9 kcal mol−1), which has a covalent bond between the N atom of the substrate and MIO, as well as two transition states (TS1 and TS2). TS1 (14.4 kcal mol−1) corresponds to a proton transfer from the substrate to the N1 atom of MIO by Tyr300OH. Thus, a tandem nucleophilic activation of the substrate and electrophilic activation of MIO happens. TS2 (5.2 kcal mol−1) indicates a concerted CN bond breaking of the N‐MIO intermediate and deprotonation of the pro‐S β position by Tyr60. Calculations elucidate the role of enzymic bases (Tyr60 and Tyr300) and other catalytically relevant residues (Asn203, Arg303, and Asn333, Asn435), which are fully conserved in the amino acid sequences and in 3D structures of all known MIO‐containing ammonia lyases and 2,3‐aminomutases.
New Bithiazole‐Based Sensitizers for Efficient and Stable Dye‐Sensitized Solar Cells
Authors: He Jinxiang , Guo Fuling , Li Xin , Wu Wenjun , Yang Jiabao , Hua Jianli 
Published: May 2012

AbstractA series of new push–pull organic dyes (BT‐I–VI), incorporating electron‐withdrawing bithiazole with a thiophene, furan, benzene, or cyano moiety, as π spacer have been synthesized, characterized, and used as the sensitizers for dye‐sensitized solar cells (DSSCs). In comparison with the model compound T1, these dyes containing a thiophene moiety between triphenylamine and bithiazole display enhanced spectral responses in the red portion of the solar spectrum. Electrochemical measurement data indicate that the HOMO and LUMO energy levels can be tuned by introducing different π spacers between the bithiazole moiety and cyanoacrylic acid acceptor. The incorporation of bithiazole substituted with two hexyl groups is highly beneficial to prevent close π–π aggregation, thus favorably suppressing charge recombination and intermolecular interaction. The overall conversion efficiencies of DSSCs based on bithiazole dyes are in the range of 3.58 to 7.51 %, in which BT‐I‐based DSSCs showed the best photovoltaic performance: a maximum monochromatic incident photon‐to‐current conversion efficiency (IPCE) of 81.1 %, a short‐circuit photocurrent density (Jsc) of 15.69 mA cm−2, an open‐circuit photovoltage (Voc) of 778 mV, and a fill factor (ff) of 0.61, which correspond to an overall conversion efficiency of 7.51 % under standard global AM 1.5 solar light conditions. Most importantly, long‐term stability of the BT‐I–III‐based DSSCs with ionic‐liquid electrolytes under 1000 h of light soaking was demonstrated and BT‐II with a furan moiety exhibited better photovoltaic performance of up to 5.75 % power conversion efficiency.
CuII‐Catalyzed Asymmetric Hydrosilylation of Diaryl‐ and Aryl Heteroaryl Ketones: Application in the Enantioselective Synthesis of Orphenadrine and Neobenodine
Authors: Sui Yao‐Zong , Zhang Xi‐Chang , Wu Jun‐Wen , Li Shijun , Zhou Ji‐Ning , Li Min , Fang Wenjun , Chan Albert S. C. , Wu Jing 
Published: May 2012

AbstractWith certain amounts of sodium tert‐butoxide and tert‐butanol as additives, catalytic amounts of an inexpensive and easy‐to‐handle copper source Cu(OAc)2⋅H2O, a commercially available and air‐stable non‐racemic dipyridylphosphine ligand, as well as the stoichiometric desirable hydride donor polymethylhydrosiloxane (PMHS), formed a versatile in situ catalyst system for the enantioselective reduction of a broad spectrum of prochiral diaryl and aryl heteroarylketones in air, in high yields and with good to excellent enantioselectivities (up to 96 %). In particular, the practical viability of this process was evinced by its successful applications in the asymmetric synthesis of optically enriched potent antihistaminic drugs orphenadrine and neobenodine.
Intermolecular chiral assemblies in R(−) and S(+) 2‐butanol detected by microcalorimetry measurements
Authors: Cogan Uri , Shpigelman Avi , Portnaya Irina , Rutenberg Abraham , Scolnik Yosef , Shinitzky Meir 
Published: May 2012

AbstractSupramolecular chiral assemblies of R(−) and S(+) 2‐butanol, in their neat form or when dissolved in their nonchiral isomer isobutanol, were evaluated by isothermal titration calorimetry (ITC) ensuing mixing. Dilution of 0.5 M solution of R(−) 2‐butanol in isobutanol into the latter liberated heat of several calories per mole, which was approximately double than that obtained in parallel dilutions of S(+) 2‐butanol in isobutanol. The ITC dilution profiles indicated an estimate of about 100 isobutanol solvent molecules surrounding each of the 2‐butanol enantiomers, presumably arranged in chiral configurations, with different adopted order between the isomers. Mixings of neat R and S 2‐butanol were followed by endothermic ITC profiles, indicating that, in racemic 2‐butanol, both the supramolecular order and the intermolecular binding energies are lower than in each of the neat chiral isomers. The diversion from symmetrical ITC patterns in these mixings indicated again a subtle difference in molecular organization between the neat enantiomers. It should be noted that the presence of impurities, α‐pinene and teterhydrofuran, at a level totaling 0.5%, did not influence the ITC heat flow profiles. The findings of this study demonstrate for the first time that chiral solutes in organic solvents are expected to acquire asymmetric solvent envelopes that may be different between the enantiomers, thus broadening this phenomenon beyond the previously demonstrated cases in aqueous solutions. Chirality 24:500–505, 2012. © 2012 Wiley Periodicals, Inc.
Mercury in Thermal Power Plants: Chemical Behavior and Possibilities for Separation
Authors: Scheffknecht Günter , Farr Silvio , Heidel Barna , Schwämmle Tobias , Brechtel Kevin 
Published: May 2012

AbstractDie weitere Absenkung der Emissionen von Quecksilber aus fossil befeuerten Kraftwerken erfordert eine Verbesserung der bestehenden Rauchgasreinigungssysteme oder den Einsatz von neuen oder adaptierten Prozessen. Dabei können spezielle Adsorbentien, zur Quecksilberoxidation verbesserte SCR‐DeNOx‐Katalysatoren oder Additive zur Quecksilberumwandlung und Abscheidung in nassen Rauchgasentschwefelungsanlagen eigesetzt werden. Da die chemischen Zusammenhänge der verschiedenen Quecksilberspezies von den Betriebsparametern der einzelnen Rauchgasreinigungsanlagen abhängen, ist ein detailliertes Verständnis der Vorgänge bei der Quecksilberrückhaltung von großer Bedeutung.
Computer‐assisted image analysis of human cilia and Chlamydomonas flagella reveals both similarities and differences in axoneme structure
Authors: O'Toole Eileen T. , Giddings Thomas H. , Porter Mary E. , Ostrowski Lawrence E. 
Published: May 2012

AbstractIn the past decade, investigations from several different fields have revealed the critical role of cilia in human health and disease. Because of the highly conserved nature of the basic axonemal structure, many different model systems have proven useful for the study of ciliopathies, especially the unicellular, biflagellate green alga Chlamydomonas reinhardtii. Although the basic axonemal structure of cilia and flagella is highly conserved, these organelles often perform specialized functions unique to the cell or tissue in which they are found. These differences in function are likely reflected in differences in structural organization. In this work, we directly compare the structure of isolated axonemes from human cilia and Chlamydomonas flagella to identify similarities and differences that potentially play key roles in determining their functionality. Using transmission electron microscopy and 2D image averaging techniques, our analysis has confirmed the overall structural similarity between these two species, but also revealed clear differences in the structure of the outer dynein arms, the central pair projections, and the radial spokes. We also show how the application of 2D image averaging can clarify the underlying structural defects associated with primary ciliary dyskinesia (PCD). Overall, our results document the remarkable similarity between these two structures separated evolutionarily by over a billion years, while highlighting several significant differences, and demonstrate the potential of 2D image averaging to improve the diagnosis and understanding of PCD. © 2012 Wiley Periodicals, Inc
Role of Well‐Being Therapy in Achieving a Balanced and Individualized Path to Optimal Functioning
Authors: Ruini Chiara , Fava Giovanni A. 
Published: May 2012

A specific psychotherapeutic strategy for increasing psychological well‐being and resilience, well‐being therapy (WBT), based on Ryff's conceptual model, has been developed and tested in a number of randomized controlled trials. The findings indicate that flourishing and resilience can be promoted by specific interventions leading to a positive evaluation of one's self, a sense of continued growth and development, the belief that life is purposeful and meaningful, the possession of quality relations with others, the capacity to manage effectively one's life and a sense of self‐determination. A decreased vulnerability to depression, mood swings and anxiety has been demonstrated after WBT in high‐risk populations. School interventions based on the principles of WBT have been found to yield both promotion of well‐being and decrease of distress compared with control groups. The differential technical characteristics and indications of WBT are described, with a special reference to the promotion of an individualized and balanced path to achieve optimal human functioning, avoiding the polarities in positive psychological dimensions. Copyright © 2012 John Wiley & Sons, Ltd.Key Practitioner Message

A specific psychotherapeutic strategy, well‐being therapy, for modifying the levels of psychological well‐being has been developed and tested.
In controlled trials, it has yielded significant benefits in clinical populations, particularly as to vulnerability to affective alterations.
Well‐being therapy may help in achieving flexibility and balance in psychological dimensions that underlie optimal human functioning.
Best results are achieved when it is applied to the sub‐acute phase of mood and anxiety disorders, in a sequential model.
Well‐being therapy may have a preventive role in general populations and particularly in children.
Early complexity supports development of motor behaviors in the first months of life
Authors: Dusing Stacey C. , Thacker Leroy R. , Stergiou Nicholas , Galloway James C. 
Published: May 2012

AbstractComplexity in motor behavior is a hallmark of healthy systems. The purpose of this study was to investigate postural complexity during development of early motor behaviors and under two conditions. Twenty‐two infants participated from 1 to 6 months of age. Linear and nonlinear measures of displacement of the center of pressure at the base of support were used to quantify magnitude and temporal structure of postural control. Behavioral coding was used to quantify the emergence of midline head control and early reaching. Results suggest that infants have complexity in postural control strategies early in development. This complexity decreases as infants learn motor behaviors, even when magnitude of the postural variability does not change. Infants were able to adapt the magnitude of postural control variability under different conditions. We propose that infants proceed through three stages which support the infant's ability to adapt motor behaviors. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 404–414, 2013
Efficient Triplet–Triplet Annihilation Upconversion with Platinum(II) Bis(arylacetylide) Complexes That Show Long‐Lived Triplet Excited States
Authors: Ji Shaomin , Wu Wanhua , Zhao Jianzhang , Guo Huimin , Wu Wenting 
Published: May 2012

AbstractNN–PtII–bis(acetylide) complexes [NN = 4,4′‐bis(tert‐butyl‐2,2′‐bipyridine) (dbbpy)] with ethynylpyrene (Pt‐2) or 4‐ethynyl‐1,8‐naphthalimide ligands (Pt‐3) that show long‐lived 3IL triplet excited states (τT = 118.0 μs) were used as new triplet sensitizers for triplet–triplet annihilation (TTA) based upconversion (UC). UC quantum yields of up to 18.1 % were observed. We found that the triplet–triplet energy‐transfer (TTET) processes, which are crucial for the TTA UC, were improved by up to 150‐fold and 250‐fold with Pt‐2 (Stern–Volmer quenching constant KSV = 5.70 × 105 M–1) and Pt‐3 (KSV = 9.64 × 105 M–1), respectively, relative to the model complex dbbpy–PtII–bis(phenylacetylide) (Pt‐1) (KSV = 3.80 × 103 M–1). The efficient upconversion is attributed to the long‐lived triplet excited states as well as the high T1‐state energy level of the sensitizers Pt‐2 and Pt‐3.
Polyfunctional β‐Dicarbonyl Compounds by Michael Addition Reactions of Ester Enolates to α‐Benzylidene and α‐Alkylidene‐β‐dicarbonyl Compounds
Authors: Holan Martin , Pohl Radek , Císařová Ivana , Jahn Ullrich 
Published: May 2012

AbstractThe scope and stereoselectivity of the Michael addition of ester enolates to α‐benzylidene and α‐alkylidene β‐dicarbonyl compounds was studied. Most substrates reacted in good to excellent yields. Michael acceptors bearing carboxylic functionalities reacted directly in the β‐position, whereas aldol and Michael addition competed with unsaturated ketones. The diastereoselectivity of the process is dependent on the substitution pattern of the Michael acceptor and the geometry of the enolate. (Z)‐Enolates add to unsaturated malonates or dibenzoylmethane derivatives with good anti‐selectivity, whereas (E)‐enolates afforded the syn‐diastereomers predominately. Unsaturated nitriles and Meldrum's acid derivatives reacted with low diastereoselectivity. A stereochemical model is proposed that accounts for all experimental results and allows the stereochemical outcome to be predicted.
Chemical Bonding in Coronene, Isocoronene, and Circumcoronene
Authors: Popov Ivan A. , Boldyrev Alexander I. 
Published: May 2012

AbstractChemical‐bonding analysis in coronene, isocoronene, and circumcoronene has been performed by using the Adaptive Natural Density Partitioning (AdNDP) method. This analysis revealed that coronene and isocoronene have two globally delocalized concentric π‐systems. Circumcoronene does not have globally delocalized π‐systems; instead, it has seven local sextets and can be represented by a single Clar structure. Thus, today there are a few known polycyclic aromatic hydrocarbons with two concentric π‐systems, but there are as yet no examples of such molecules with three or more concentric π‐systems. The results revealed by the AdNDP analysis are consistent with the results obtained by the current‐density maps, NICS and NICSZZ indices as well as MCI, PDI, Iring and δ indices.
Structure of the O‐Polysaccharide of Providencia alcalifaciens O22 Containing D‐Glyceramide 2‐Phosphate
Authors: Ovchinnikova Olga G. , Kocharova Nina A. , Bialczak‐Kokot Magdalena , Shashkov Alexander S. , Rozalski Antoni , Knirel Yuriy A. 
Published: May 2012

AbstractO‐Polysaccharides (O‐antigens) are highly diverse glycopolymers present on the cell surface of Gram‐negative bacteria, including the human opportunistic pathogen Providencia alcalifaciens. They define serospecificity of strains and are used for the serotyping of bacteria. In this work, a phosphorylated O‐polysaccharide was isolated from P. alcalifaciens O22 and analyzed by chemical methods, ESI‐MS, and 1H, 13C, and 31P NMR spectroscopy. It was found to contain two unusual components, 2‐acetamido‐4‐amino‐2,4,6‐trideoxy‐D‐galactose (D‐FucNAc4N) and D‐glyceramide 2‐phosphate (D‐GroAN‐2‐P), the latter being identified for the first time in bacterial polysaccharides. The structure of the trisaccharide repeating unit of the O‐polysaccharide was established to be 4)‐(D‐GroAN‐2‐P‐3‐)‐‐D‐GalNAc‐(14)‐‐D‐Gal‐(13)‐‐D‐FucNAc4N‐(1.
A Conductometric Sensor Specific for Cationic Surfactants
Authors: Hnaien Mouna , Dzyadevych Sergei , Lagarde Florence , Jaffrezic‐Renault Nicole 
Published: May 2012

AbstractIn this work, a fast, sensitive and miniaturised conductometric sensor based on interdigitated electrodes, working in differential mode, was developed for the determination of cationic surfactants. The membrane was composed of a polymer (PVC), a plasticizer (dinonylphtalate (DNP)) and a carrier (sodium tetraphenylborate (NaBΦ4)). The sensor response was linear from at least 10−9 M to 10−2 M for dodecyltrimethylammonium (DTA+). No significant loss of sensor response was observed after 8 weeks. The sensor exhibited a lower sensitivity and a narrower dynamic range for tetrabutylammonium, decyltrimethylammonium and cetyltrimethylammonium cationic surfactants. A ten times lower sensitivity was observed for laurylsulfate anionic surfactant, (LS−).
Direct Electrochemistry and Electrocatalytic Properties of Hemoglobin Immobilized on Carbon Nanotubes Ionic Liquid Electrode
Authors: Moheimanian Niloofar , Raoof Jahan Bakhsh , Safavi Afsaneh , Ojani Reza 
Published: May 2012

AbstractHemoglobin (Hb) was directly immobilized on a multiwalled carbon nanotubes ionic liquid electrode by immersing this electrode in a solution consisting of Hb and 1‐octyl‐pyridinium chloride as an ionic liquid. The immobilized Hb displayed a pair of well‐defined cyclic voltammetric peaks with a formal potential of −0.187 V in acetate buffer solution, pH 5.0. This modified electrode exhibits fast response, a long linearity range, a low detection limit, high stability and excellent sensitivity through hydrogen peroxide detection with a detection limit (3σ) of 3.18 µM. The electrode was also used for electrocatalysis and voltammetric determination of oxygen and trichloroacetic acid.
Mimicking a Receptor for Cyanide Ion Based on Ion Imprinting and Its Applications in Potential Transduction
Authors: Abd‐Rabboh Hisham S. M. , Kamel Ayman H. 
Published: May 2012

AbstractUsing the strategy of template polymerization, a presynthesized specific metal‐complexing polymer (poly(methacryloylhistidine‐Ni(II)‐CN−), Ni‐CN/IP) has been specifically used to recognize cyanide ion. As described previously, nickel(II)‐methacryloylhistidine dihydrate complex monomer was synthesized and reacted with KCN to produce the monomer‐template complex. This monomer‐template complex phase was polymerized in a dispersion medium. After polymerization, the template (CN−) was removed from the Ni‐CN/IP, producing CN− ion imprinted metal‐chelate polymer. The synthesized ion imprinted polymer is examined as a novel potential cyanide selective ionophore in polymeric membrane type ion selective electrodes. Membranes formulated with Ni‐CN/IP are shown to exhibit enhanced potentiometric selectivity for cyanide over more lipophilic anions including perchlorate, iodide, and thiocyanate. Addition of lipophilic cationic sites into the organic membranes enhanced the response and selectivity towards CN− ion, while addition of lipophilic anionic sites deteriorated the response but enhanced the selectivity, indicating that the Ni‐CN/IP particles behaves via the so‐called “mixed‐mode” response mechanism. The fabricated sensors possessed good performance characteristics, in terms of life span, selectivity for CN− ion over a wide range of other interfering anions, fast response, stability and high reproducibility. Applications for direct determination of cyanide ion in hazardous wastes using the proposed sensors showed good correlation with data obtained using commercial solid state cyanide electrode, with no significant difference in the t‐test values with 95 % confidence level. An F‐test revealed that the standard deviations of the replicate sample measurements obtained by the two methods were not significantly different.