bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Relationship between the Electrochemical and Chemical Oxidation of Ferrocene‐Containing Carbonyl‐Phosphane‐β‐Diketonato‐Rhodium(I) Complexes – Cytotoxicity of [Rh(FcCOCHCOPh)(CO)(PPh3)]
Authors: Conradie Jeanet , Swarts Jannie C. 
Published: April 2011

AbstractFerrocene‐containing rhodium(I) complexes of the type [Rh(FcCOCHCOR)(CO)(PPh3)] with R = Fc (ferrocenyl),1, Ph (phenyl),2, CH3,3, and CF3,4, have been studied by cyclic voltammetry (CV) and bulk electrolysis techniques in CH3CN. Two isomers for complexes2–4were detected. Results are consistent with RhIbeing oxidised first in an electrochemically irreversible two‐electron transfer process, followed by the electrochemical reversible oxidation of each ferrocenyl group in a one‐electron transfer process at slightly larger potentials. Only theEpa(Rh) CV peaks resolved into two separate waves, each one being associated with an isomer. Slow isomerisation kinetics allowed the detection of two isomers of2–4.Epa(Rh) and other compound physical parameters relates to the second‐order rate constant for the oxidative addition of CH3I to complexes1–4in acetone. Rhodium(III) reduction of oxidised1,2,3and4was observed at large negative potentials, while for [Rh(FcCOCHCOCF3)(CH3)(I)(CO)(PPh3)] (9) it was observed at –1.492 V vs. Fc/Fc+. Complex2was slightly more cytotoxic than the free FcCOCH2COPh ligand but less cytotoxic than cisplatin.
On the Reduction of NC Chelated Organoantimony(III) Chlorides
Authors: Dostál Libor , Jambor Roman , Růžička Aleš , Šimon Petr 
Published: April 2011

AbstractThe conversion of organolithium compound LLi, for which L = [o‐C6H4(CH=NC6H3iPr2‐2,6)]–, with antimony chloride gave the molecular chlorides LSbCl2 (1) and L2SbCl (2) depending on the molar ratio used (either 1:1 or 2:1). Bothcompounds were characterized by using 1H and 13C NMR spectroscopy, elemental analysis and single‐crystal X‐ray diffraction. The reaction of 1 with two molar equivalents of K[B(sBu)3H] led to smooth formation of compound L4Sb4 (3) as a result of hydrogen elimination from the unstable hydrido compound. On the contrary, a similar reaction between 2 and K[B(sBu)3H] (1:1) did not result in hydrogen elimination and the formation of expected distibine L2SbSbL2, but an addition of an in situ generated L2Sb–H bond across the C=N functionality in the pendant arm of one of the ligands was observed. The reduction of compound 2 with an excess amount of magnesium was strongly dependent on the reaction time. The distibine L2SbSbL2 (5) could be isolated after 4–5 h from this reaction mixture. Elongation of the reaction time to 1 d (and more) gave a more complicated reaction mixture, in which three products, distibine 5, compound 3 and organomagnesium compound L2Mg(THF) (6), were characterized by single‐crystal X‐ray diffraction in addition to other unidentified products. These results can be rationalized by a migration of the ligand L from the antimony atom to the magnesium, thus explaining formation of both L4Sb4 (3) compound and L2Mg(THF) (6).
An efficient extraction and clean‐up procedure for pesticide determination in olive oil
Authors: Sobhanzadeh Elham , Bakar Nor Kartini Abu , Abas Mhd Radzi Bin , Nemati Keivan 
Published: April 2011

AbstractThis work reports a simple, rapid, and effective extraction method based on liquid–liquid extraction (LLE) followed by matrix solid‐phase dispersion‐sonication for detection, identification and quantification of multiclass pesticides in virgin olive oil using liquid chromatography mass spectrometry (LC‐QTOF‐MS). LLE to extract pesticide residues in virgin olive oil was performed in order to study the centrifugation efficiency to obtain high recovery yield and low co‐extract fat residue in the final extract. Different suitable parameters of MSPD procedure were evaluated, such as nature of dispersing phase, clean‐up adsorbent, and volume of eluting solvent (acetonitrile) in different extraction conditions, with or without sonication. The best results were obtained using 5 g of virgin olive oil, 2 g of PSA as dispersant sorbent, 2 g of Florisil/GCB (70:30 w/w) as clean‐up sorbent, and 15 mL of acetonitrile as eluting solvent under conditions of 15 min ultrasonic bath at RT. Method validation was performed in order to study sensitivity, linearity, precision, and accuracy. Average recoveries ranged between 73.7 and 104.2% with relative SDs 5.3–13.4% at three concentration levels (25, 50, and 100 µg/kg). Detection and quantification limits ranged from 1.5 to 5 µg/kg and 3 to 9 µg/kg, respectively.
Fatty acids of Thespesia populnea: Mass spectrometry of picolinyl esters of cyclopropene fatty acids
Authors: Knothe Gerhard , Rashid Umer , Yusup Suzana , Anwar Farooq 
Published: April 2011

AbstractThespesia populnea belongs to the plant family of Malvaceae which contain cyclopropane and cyclopropene fatty acids. However, previous literature reports vary regarding the content of these compounds in Thespesia populnea seed oil. In this work, the content of malvalic acid (8,9‐methylene‐9‐heptadecenoic acid) in the fatty acid profile of Thespesia populnea seed oil was approximately 7% by GC. Two cyclopropane fatty acids were identified, including dihydrosterculic acid. The methyl and picolinyl esters of Thespesia populnea seed oil were also prepared. The mass spectrum of picolinyl malvalate was more closely investigated, especially an ion at m/e 279, which does not fit the typical series of ions observed in picolinyl esters. It is shown that this ion is caused by cleavage at the picolinyl moiety and contains the fatty acid chain without the picolinyl moiety. This type of cleavage has previously not been observed prominently in picolinyl esters and may therefore be diagnostic for picolinyl esters of cyclopropene fatty acids. The NMR spectra of Thespesia populnea methyl esters are also discussed.Practical applications: The work reports the fatty acid composition of Thespesia seed oil whose derivatives have not yet been extensively utilized for industrial purposes, for example, biodiesel. Knowing this composition is essential for understanding potential uses and, for example, in case of biodiesel the fuel properties. Besides this issue, some data (mass spectrometry and NMR) crucial for obtaining the composition information are analyzed in detail. The biodiesel properties of methyl esters of Thespesia populnea will be reported separately.
[2+2+2] Cycloadditions of Alkynylynamides – A Total Synthesis of Perlolyrine and the First Total Synthesis of “Isoperlolyrine”
Authors: Dassonneville Benjamin , Witulski Bernhard , Detert Heiner 
Published: April 2011

AbstractThe total syntheses of the carboline alkaloids perlolyrine and “isoperlolyrine” are reported. Key‐steps of the syntheses are Negishi coupling reactions on alkynylynamides and their metal‐catalyzed [2+2+2] cycloadditions with nitriles to form the β‐ and γ‐carboline cores. The choice of the catalyst strongly affects the β/γ ratio. Spectroscopic features of the γ‐isomer are distinctly different from those of the naturally occurring isoperlolyrine.
Selenation/Thionation of α‐Amino Acids: Formation and X‐ray Structures of Diselenopiperazine and Dithiopiperazine and Related Compounds
Authors: Hua Guoxiong , Fuller Amy L. , Bühl Michael , Slawin Alexandra M. Z. , Woollins J. Derek 
Published: April 2011

AbstractN‐Phenylglycine reacts with an equivalent of 2,4‐bis(phenyl)‐1,3‐diselenadiphosphetane 2,4‐diselenide (Woollins' reagent, WR) to generate as the major product 1,4‐diphenylpiperazine‐2,5‐diselenone and as the minor product 1,4‐diphenyl‐5‐selenoxopiperazin‐2‐one. Whereas, reacting N‐phenylglycine with an equivalent of 2,4‐bis(4‐methoxyphenyl)‐1,3‐dithia‐2,4‐diphosphetane 2,4‐disulfide (Lawesson's reagent, LR) affords 1,4‐diphenylpiperazine‐2,5‐dithione and N‐phenyl‐2‐(phenylamino)ethanethioamide. 2‐Phenylglycine treated with an equivalent of Woollins' reagent under identical reaction conditions leads to only the formation of 2,5‐diphenylpyrazine. Six X‐ray structures are reported. DFT‐B3LYP calculations suggest that the planar conformation is around 2 kcal/mol less stable than the puckered conformation for the bis‐seleno derivative.
Perspectives on CO2 capture and storage
Authors: Johnsson Filip 
Published: April 2011

AbstractThe last decade has seen a significant increase in the research and development of CO2 capture and storage (CCS) technology. CCS is now considered to be one of the key options for climate change mitigation. This perspective provides a brief summary of the state of the art regarding CCS development and discusses the implications for the further development of CCS, particularly with respect to climate change policy. The aim is to provide general perspectives on CCS, although examples used to illustrate the prospects for CCS are mainly taken from Europe.The rationale for developing CCS should be the over‐abundance of fossil fuel reserves (and resources) in a climate change context. However, CCS will only be implemented if society is willing to attach a sufficiently high price to CO2 emissions. Although arguments have been put forward both in favor and against CCS, the author of this perspective argues that the most important outcome from the successful commercialization of CCS will be that fossil‐fuel‐dependent economies will find it easier to comply with stringent greenhouse gas (GHG) reduction targets. In contrast, failure to implement CCS will require that the global community agrees almost immediately to start phasing out the use of fossil fuels; such an agreement seems more unrealistic than reaching a global agreement on stringent GHG reductions. Thus, in the near term, it is crucial to initiate demonstration projects, such as those supported by the EU. If this is not done, there is a risk that the introduction of CCS will be significantly delayed. Among the stakeholders in CCS technologies (R&D actors in industry and academia), the year 2020 is typically considered to be the year in which CCS will be commercially available. Considering the lead times for CCS development and the slow pace of implementation of climate policy (post‐Copenhagen), the target year of 2020 seems rather optimistic. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd
Central nervous system dysfunction in a mouse model of Fa2h deficiency
Authors: Potter Kathleen A. , Kern Michael J. , Fullbright George , Bielawski Jacek , Scherer Steven S. , Yum Sabrina W. , Li Jian J. , Cheng Hua , Han Xianlin , Venkata Jagadish Kummetha , Akbar Ali Khan P. , Rohrer Bärbel , Hama Hiroko 
Published: April 2011

AbstractFatty acid 2‐hydroxylase (FA2H) is responsible for the synthesis of myelin galactolipids containing hydroxy fatty acid (hFA) as the N‐acyl chain. Mutations in the FA2H gene cause leukodystrophy, spastic paraplegia, and neurodegeneration with brain iron accumulation. Using the Cre‐lox system, we developed two types of mouse mutants, Fa2h−/− mice (Fa2h deleted in all cells by germline deletion) and Fa2hflox/flox Cnp1‐Cre mice (Fa2h deleted only in oligodendrocytes and Schwann cells). We found significant demyelination, profound axonal loss, and abnormally enlarged axons in the CNS of Fa2h−/− mice at 12 months of age, while structure and function of peripheral nerves were largely unaffected. Fa2h−/− mice also exhibited histological and functional disruption in the cerebellum at 12 months of age. In a time course study, significant deterioration of cerebellar function was first detected at 7 months of age. Further behavioral assessments in water T‐maze and Morris water maze tasks revealed significant deficits in spatial learning and memory at 4 months of age. These data suggest that various regions of the CNS are functionally compromised in young adult Fa2h−/− mice. The cerebellar deficits in 12‐month‐old Fa2hflox/flox Cnp1‐Cre mice were indistinguishable from Fa2h−/− mice, indicating that these phenotypes likely stem from the lack of myelin hFA‐galactolipids. In contrast, Fa2hflox/flox Cnp1‐Cre mice did not show reduced performance in water maze tasks, indicating that oligodendrocytes are not involved in the learning and memory deficits found in Fa2h−/− mice. These findings provide the first evidence that FA2H has an important function outside of oligodendrocytes in the CNS. © 2011 Wiley‐Liss, Inc.
Novel flavohemoglobins of mycobacteria
Authors: Gupta Sanjay , Pawaria Sudesh , Lu Changyuan , Yeh Syun‐Ru , Dikshit Kanak L. 
Published: April 2011

AbstractFlavohemoglobins (flavoHbs) constitute a distinct class of chimeric hemoglobins in which a globin domain is coupled with a ferredoxin reductase such as FAD‐ and NADH‐binding modules. Structural features and active site of heme and reductase domains are highly conserved in various flavoHbs. A new class of flavoHbs, displaying crucial differences in functionally conserved regions of heme and reductase domains, have been identified in mycobacteria. Mining of microbial genome data indicated that the occurrence of such flavoHbs might be restricted to a small group of microbes unlike conventional flavoHbs that are widespread among prokaryotes and lower eukaryotes. One of the representative flavoHbs of this class, encoded by Rv0385 gene (MtbFHb) of Mycobacterium tuberculosis, has been cloned, expressed, and characterized. The ferric and deoxy spectra of MtbFHb displayed a hexacoordinate state indicating that its distal site may be occupied by an intrinsic amino acid or an external ligand and it may not be involved in nitric oxide detoxification. Phylogenetic analysis revealed that mycobacterial flavoHbs constitute a separate cluster distinct from conventional flavoHbs and may have novel function(s). © 2011 IUBMB IUBMB Life, 63(5): 337–345, 2011
Enhancing blood compatibility of biodegradable polymers by introducing sulfobetaine
Authors: Cao Jun , Chen Yuan‐Wei , Wang Xin , Luo Xiang‐Lin 
Published: April 2011

AbstractNovel biodegradable polycaprolactone containing N,N′‐bis (2‐hydroxyethyl) methylamine ammonium propane sulfonate (PCL‐APS) was synthesized by ring‐opening polymerization. The resulting polymers were characterized by nuclear magnetic resonance spectrum (NMR), Fourier transform infrared (FTIR) spectroscopy, gel permeation chromatograph (GPC), differential scanning calorimetry (DSC), and water contact angle (WCA). These measurements showed that the APS unit was introduced into polymers. The hydrolysis of PCL‐APS was evaluated by soaking the polymer membranes in a pH = 3.20 acid solution. The rate of weight loss was increased with the content of APS increasing in polymer. The compatibility of polymers were evaluated by platelet adhesion, hemolytic test, and activated partial thromboplastic time (APTT) and prothrombin time (PT) experiments. Results showed that adhered platelets deceased after introducing sulfobetaine as compared to the control PCL, little hemolysis took place on PCL‐APS, and APTT of PCL‐APS polymers was prolonged than that of control PCL. Therefore, polycaprolactone containing sulfobetaine is a promising biodegradable polymer with good blood compatibility. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
The role of reactive silicates on the structure/property relationships and cell response evaluation in polyurethane nanocomposites
Authors: Rueda Lorena , Garcia Inaki , Palomares Teodoro , Alonso‐Varona Ana , Mondragon Inaki , Corcuera Marian , Eceiza Arantxa 
Published: April 2011

AbstractPrecursors of polyurethane chains have been reacted by means of in situ polymerization with organically modified montmorillonite clay to obtain polyurethane nanocomposites containing from 1 to 4 wt % of nanoreinforcement. The effective final dispersion of inorganic component at nanometric scale was investigated by X‐ray diffraction, atomic force microscopy, and transmission electron microscopy. In addition, the effect of the nanoreinforcement incorporation on thermal and mechanical behavior of polyurethane nanocomposites was evaluated. Nanocomposites showed similar mechanical properties to polyurethanes containing high‐hard segment contents with higher tensile modulus and a decrease in elastomeric properties of polyurethane materials. Finally, biocompatibility studies using L‐929 fibroblast have been carried out to examine in vitro cell response and cytotoxicity of the matrix and their nanocomposite materials. Results suggested that the organic modifier in the clay is unsuitable for biomedical devices in spite of the fact that the matrix is a good candidate for cell adhesion and proliferation. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Osteoblast adhesion to functionally graded hydroxyapatite coatings doped with silver
Authors: Sandukas Stefan , Yamamoto Akiko , Rabiei Afsaneh 
Published: April 2011

AbstractSilver‐doped functionally graded hydroxyapatite (Ag‐FGHA) coatings have been prepared on glass and titanium substrates by ion beam assisted deposition (IBAD) method with in situ heat treatment, and the biological response and dissolution properties of the coatings have been examined. Three Ag‐FGHA coatings with different percentages of silver (1, 3, and 6.6 wt % Ag) were compared with pure FGHA (without Ag) as a control. MC 3T3‐E1 murine osteoblast cells were cultured on FGHA and Ag‐FGHA coating surfaces, and the number of adhered cells after 1, 4, and 7 days was counted. Micromanipulation of live single cells was performed to quantitatively compare cell affinity among the four coating compositions. Results showed that FGHA‐Ag1 coating (with 1 wt % Ag) had the highest number of adhered cells after each incubation period, as well as the highest cell affinity after 24‐h incubation. Surface profilometry was performed to determine surface roughness average (Ra) of coating surfaces before and after immersion in high‐purity water, showing that all surfaces initially had roughness averages below 200 nm, while after immersion, roughness average of FGHA‐Ag1 surface was significantly increased (Ra = 404 +/− 100.8 nm), attributed to the highest rate of dissolution. Release rate of Ag+ ions in solution was measured, showing release rates of silver ions for all Ag‐doped coatings were initially high and then gradually decreased to a minimum over time, which is the expected dissolution of functionally graded coatings. It is concluded that FGHA‐Ag1 coating promoted the highest degree of osteoblast adhesion because of optimal dissolution rate and nontoxic Ag percentage. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
High-frequency, low-intensity vibrations increase bone mass and muscle strength in upper limbs, improving autonomy in disabled children
Authors: Reyes M Loreto , Hernández Marta , Holmgren Luz J , Sanhueza Enrique , Escobar Raúl G 
Published: April 2011

Abstract
Disuse osteoporosis in children is a progressive disease that can affect quality of life. High-frequency, low-magnitude vibration (HFLMV) acts as an anabolic signal for bone and muscle. We undertook a prospective, randomized, double-blind, placebo-controlled clinical trial to assess the efficacy and safety of regional HFLMV in disabled children. Sixty-five children 6 to 9 year of age were randomized into three groups: placebo, 60 Hz, and 90 Hz. In the two active groups, a 0.3-g mechanical vibration was delivered to the radii and femurs for 5 minutes each day. After 6 months, the main endpoint was bone mineral density (BMD) at the ultradistal radius (UDR), 33% radii (33%R), and femoral necks (FN). Secondary endpoints were area and bone mineral content (BMC) at the UDR, 33%R, and FN; grip force of the upper and lower limbs; motor function; and PedsQL evaluation. An intention-to-treat analysis was used. Fifty-seven children (88%) completed the protocol. A significant increase was observed in the 60-Hz group relative to the other groups in BMD at the UDR (p = .011), in grip force of the upper limbs (p = .035), and in the “daily activities item” (p = .035). A mixed model to evaluate the response to intervention showed a stronger effect of 60 Hz on patients with cerebral palsy on the UDR and that between-subject variability significantly affected the response. There were no reported side effects of the intervention. This work provides evidence that regional HFLMV is an effective and safe strategy to improve bone mass, muscle strength, and possibly independence in children with motor disabilities. © 2011 American Society for Bone and Mineral Research
Does photoelectrocatalysis by TiO2 work?
Authors: Egerton Terry A. 
Published: April 2011

AbstractBACKGROUND: This paper examines TiO2 photoelectrocatalysis (PEC), a process that increases the efficiency of TiO2 photocatalysis (PC) by applying a potential to separate the UV‐generated charge carriers whose recombination typically limits photonic efficiencies of conventional photocatalysis.RESULTS: Four representative photoelectrocatalytic reactions, nitrophenol oxidation, oxalate degradation, E. coli inactivation and dye decolouration were considered. For all four, a small applied potential raised the rate of pollutant removal by TiO2 electrodes. Because the improvements were probably insufficient to make PEC technologically viable except in niche applications, rates of pollutant removal by PEC and by PC using TiO2 particle dispersions were directly compared. PEC rates were not significantly larger than rates of PC by dispersions.CONCLUSION: Discussions of the implications of these conclusions focus on whether PEC is currently limited by reactor design (irradiation geometry, or mass transfer) or by electrode materials. It is inferred that the performance of present electrodes is not limited significantly by mass transfer constraints. Since the choice of electrode materials (sol–gel or thermal electrodes) has been shown to influence PEC efficiency, recent results on titania nanotubes (TNT) are reviewed. It is concluded that the enhancement factors—the PEC:PC ratio—of TNT electrodes are no higher than those of conventional materials. Copyright © 2011 Society of Chemical Industry
Echocardiographic appearance of a hydatid cyst of the papillary muscle and chordae tendineae
Authors: Fabijanić Damir , Bulat Cristijan , Letica Dalibor , Nenadić Denis , Pešutić‐Pisac Valdi , Carević Vedran 
Published: April 2011

AbstractA 24‐year‐old woman with a history of hydatid disease of the lung and brain, which was treated surgically and medically with albendazole, was admitted because of syncope. Echocardiography demonstrated a mass in the anterolateral papillary muscle and chordae tendineae. Despite negative serologic tests for Echinococcus granulosus, cytology and histology of the surgically removed mass confirmed hydatid disease. The patient was discharged and treated further with albendazole and praziquantel. © 2011 Wiley Periodicals, Inc. J Clin Ultrasound 2011
A sufficient condition for planar graphs to be acyclically 5‐choosable
Authors: Chen Min , Raspaud André 
Published: April 2011

AbstractA proper vertex coloring of a graph G = (V, E) is acyclic if G contains no bicolored cycle. Given a list assignment L = {L(v)|v∈V} of G, we say G is acyclically L‐list colorable if there exists a proper acyclic coloring π of G such that π(v)∈L(v) for all v∈V. If G is acyclically L‐list colorable for any list assignment with |L(v)|≥k for all v∈V, then G is acyclically k‐choosable. In this article we prove that every planar graph without 4‐cycles and without intersecting triangles is acyclically 5‐choosable. This improves the result in [M. Chen and W. Wang, Discrete Math 308 (2008), 6216–6225], which says that every planar graph without 4‐cycles and without two triangles at distance less than 3 is acyclically 5‐choosable. © 2011 Wiley Periodicals, Inc. J Graph Theory