bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cooperative Tandem Catalysis by an Organometallic Complex and a Metalloenzyme
Authors: Denard Carl A. , Huang Hua , Bartlett Mark J. , Lu Lu , Tan Yichen , Zhao Huimin , Hartwig John F. 
Published: November 2013

AbstractAlthough chemical and enzymatic catalysts have been combined, reactions in which an organometallic catalyst and a metalloenzyme work cooperatively to create products, which cannot be generated with either catalyst alone or in comparable yields by sequential reactions of the two catalysts, have not been reported. Such reactions are challenging to achieve, in part because the milieu in which these catalysts operate are typically different. Herein, two classes of catalysts are demonstrated to react cooperatively in the same system. Combination of a metathesis catalyst and a P450 enzyme lead to a dynamic equilibration of alkenes and a selective epoxidation of the cross‐metathesis products. These results show the potential of combining the two classes of catalysts for synthetic transformations.
Chiral Silver Phosphate Catalyzed Transformation of ortho‐Alkynylaryl Ketones into 1H‐Isochromene Derivatives through an Intramolecular‐Cyclization/Enantioselective‐Reduction Sequence
Authors: Terada Masahiro , Li Feng , Toda Yasunori 
Published: November 2013

AbstractThe transformation of ortho‐alkynylaryl ketones through a cyclization/enantioselective‐reduction sequence in the presence of a chiral silver phosphate catalyst afforded 1H‐isochromene derivatives in high yield with fairly good to high enantioselectivity. An asymmetric synthesis of the 9‐oxabicyclo[3.3.1]nona‐2,6‐diene framework, which has been found in some biologically active molecules, is presented as a demonstration of the synthetic utility of this method.
Kontrolle der Form verdunstender Tropfen über die Ionenstärke: Bildung anisometrischer SiO2‐Suprapartikel
Authors: Sperling Marcel , Velev Orlin D. , Gradzielski Michael 
Published: November 2013

AbstractAnisometrische SiO2‐Suprapartikel werden durch einfache Verdunstung einer Dispersion von pyrogenem Siliciumdioxid in Wassertropfen auf einer superhydrophoben Oberfläche erhalten. Die Form der Suprapartikel wird unmittelbar durch die Salzkonzentration (NaCl) kontrolliert. Oberhalb einer Grenzkonzentration werden die Partikel anisometrisch, wie durch Lichtmikroskopie quantifiziert wurde. Das Verfahren kann leicht auf Suprapartikel mit anderen kolloidalen Komponenten übertragen werden.
Synthesis of Complex and Diverse Compounds through Ring Distortion of Abietic Acid
Authors: Rafferty Ryan J. , Hicklin Robert W. , Maloof Katherine A. , Hergenrother Paul J. 
Published: November 2013

AbstractMany compound screening collections are populated by members that possess a low degree of structural complexity. In an effort to generate compounds that are both complex and diverse, we have developed a strategy that uses natural products as a starting point for complex molecule synthesis. Herein we apply this complexity‐to‐diversity approach to abietic acid, an abundant natural product used commercially in paints, varnishes, and lacquers. From abietic acid we synthesize a collection of complex (as assessed by fraction of sp3‐hybridized carbons and number of stereogenic centers) and diverse (as assessed by Tanimoto analysis) small molecules. The 84 compounds constructed herein, and those created through similar efforts, should find utility in a variety of biological screens.
Non‐Pyrolytic, Large‐Scale Synthesis of Trichalcogenasumanene: A Two‐Step Approach
Authors: Li Xuexiang , Zhu Yongtao , Shao Jiafeng , Wang Baolin , Zhang Shangxi , Shao Yongliang , Jin Xiaojie , Yao Xiaojun , Fang Ran , Shao Xiangfeng 
Published: November 2013

AbstractTrichalcogenasumanenes were synthesized on a multigram scale through a two‐step approach that takes advantage of non‐pyrolytic cyclization and solventless ring contraction. Solid‐state structure and photophysical investigations demonstrate that these compounds are promising candidates for electronic materials.
“Metal‐Free” Catalytic Oxygen Reduction Reaction on Heteroatom‐Doped Graphene is Caused by Trace Metal Impurities
Authors: Wang Lu , Ambrosi Adriano , Pumera Martin 
Published: November 2013

AbstractThe oxygen reduction reaction (ORR) is of high industrial importance. There is a large body of literature showing that metal‐based catalytic nanoparticles (e.g. Co, Mn, Fe or hybrid Mn/Co‐based nanoparticles) supported on graphene act as efficient catalysts for the ORR. A significant research effort is also directed to the so‐called “metal‐free” oxygen reduction reaction on heteroatom‐doped graphene surfaces. While such studies of the ORR on nonmetallic heteroatom‐doped graphene are advertised as “metal‐free” there is typically no sufficient effort to characterize the doped materials to verify that they are indeed free of any trace metal. Here we argue that the claimed “metal‐free” electrocatalysis of the oxygen reduction reaction on heteroatom‐doped graphene is caused by metallic impurities present within the graphene materials.
Insights into the Metalation of Benzene and Toluene by Schlosser’s Base: A Superbasic Cluster Comprising PhK, PhLi, and tBuOLi
Authors: Unkelbach Christian , O'Shea Donal F. , Strohmann Carsten 
Published: November 2013

AbstractThe metalation of benzene by Schlosser’s base (nBuLi/tBuOK) occurs smoothly in THF at low temperatures to afford a discrete mixed‐metal Li2K4 cluster that contains phenyl anions and tert‐butoxide. The aggregate itself exhibits superbasic behavior by metalating toluene. The delocalized benzyl anion obtained this way π bonds to potassium counterions, thereby creating a 2D coordination polymer.
Recoding the Genetic Code with Selenocysteine
Authors: Bröcker Markus J. , Ho Joanne M. L. , Church George M. , Söll Dieter , O'Donoghue Patrick 
Published: November 2013

AbstractSelenocysteine (Sec) is naturally incorporated into proteins by recoding the stop codon UGA. Sec is not hardwired to UGA, as the Sec insertion machinery was found to be able to site‐specifically incorporate Sec directed by 58 of the 64 codons. For 15 sense codons, complete conversion of the codon meaning from canonical amino acid (AA) to Sec was observed along with a tenfold increase in selenoprotein yield compared to Sec insertion at the three stop codons. This high‐fidelity sense‐codon recoding mechanism was demonstrated for Escherichia coli formate dehydrogenase and recombinant human thioredoxin reductase and confirmed by independent biochemical and biophysical methods. Although Sec insertion at UGA is known to compete against protein termination, it is surprising that the Sec machinery has the ability to outcompete abundant aminoacyl‐tRNAs in decoding sense codons. The findings have implications for the process of translation and the information storage capacity of the biological cell.
Immobilization of lipase with alginate hydrogel beads and the lipase‐catalyzed kinetic resolution of α‐phenyl ethanol
Authors: Zhang Shuang , Shang Wenting , Yang Xiaoxi , Zhang Xiaogang , Huang Yunqian , Zhang Shujuan , Chen Jiawei 
Published: November 2013

ABSTRACTThe immobilization of enzymes is one of the key issues in both the field of enzymatic research and industrialization. In this article, we report a facile method for immobilizing Candida antarctica lipase B in an alginate carrier. In the presence of calcium cations, an enzyme–alginate suspension was crosslinked to form beads with a porous structure at room temperature, and the enzymes were well dispersed in the beads. The chiral resolution of α‐phenyl ethanol in the organic phase was tested by the enzyme–alginate beads. The effects of the reaction parameters, such as the enzyme concentration, temperature, and molar ratio of the substrate to the solvent, on the resolution behavior are discussed. Reuse cycle experiments for the chiral resolution of α‐phenyl ethanol demonstrated that the activity of the enzyme–alginate beads was maintained without marked deactivation up to five repeated cycles. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40178.
Reinforcement of maleated polyethylene/ground tire rubber thermoplastic elastomers using talc and wood flour
Authors: Ramezani Kakroodi Adel , Rodrigue Denis 
Published: November 2013

AbstractMaleated polyethylene (MAPE)/Ground tire rubber (GTR) thermoplastic elastomer with 50 vol % GTR was reinforced by incorporation of talc powder and wood flour. Scanning electron microscopy (SEM) reveals that maleated polyethylene (MAPE) has good compatibility with wood flour, but the adhesion with talc particles is weak. Tensile moduli of MAPE/GTR increase more significantly after inclusion of talc particles compared to wood flour. Prediction of the tensile modulus of hybrid MAPE/GTR/particle composites is successfully performed using a combination of Kerner and Halpin‐Tsai models. Elastic moduli are shown to depend strongly on both aspect ratio and level of particle dispersion in the matrix. Measurement of compression sets shows that elastic recovery of the compounds decreases after addition of solid particles. Samples having better particles/matrix compatibility show higher elastic recovery. Thermogravimetric analysis shows that inclusion of wood flour decreases thermal stability of compounds. Density and hardness of MAPE/GTR are also shown to increase after inclusion of particulate reinforcements. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40195.
Gold Nanorods with Phase‐Changing Polymer Corona for Remotely Near‐Infrared‐Triggered Drug Release
Authors: Liu Ji , Detrembleur Christophe , Grignard Bruno , De Pauw‐Gillet Marie‐Claire , Mornet Stéphane , Treguer‐Delapierre Mona , Petit Yannick , Jérôme Christine , Duguet Etienne 
Published: November 2013

AbstractHerein, we report a new drug‐delivery system (DDS) that is comprised of a near‐infrared (NIR)‐light‐sensitive gold‐nanorod (GNR) core and a phase‐changing poly(ε‐caprolactone)‐b‐poly(ethylene glycol) polymer corona (GNR@PCL‐b‐PEG). The underlying mechanism of the drug‐loading and triggered‐release behaviors involves the entrapment of drug payloads among the PCL crystallites and a heat‐induced phase change, respectively. A low premature release of the pre‐loaded doxorubicin was observed in PBS buffer (pH 7.4) at 37 °C (<10 % of the entire payload after 48 h). However, release could be activated within 30 min by conventional heating at 50 °C, above the Tm of the crystalline PCL domain (43.5 °C), with about 60 % release over the subsequent 42 h at 37 °C. The NIR‐induced heating of an aqueous suspension of GNR@PCL‐b‐PEG under NIR irradiation (802 nm) was investigated in terms of the irradiation period, power, and concentration‐dependent heating behavior, as well as the NIR‐induced shape‐transformation of the GNR cores. Remotely NIR‐triggered release was also explored upon NIR irradiation for 30 min and about 70 % release was achieved in the following 42 h at 37 °C, with a mild warming (<4 °C) of the surroundings. The cytotoxicity of GNR@PCL‐b‐PEG against the mouse fibroblastic‐like L929 cell‐line was assessed by MTS assay and good compatibility was confirmed with a cell viability of over 90 % after incubation for 72 h. The cellular uptake of GNR@PCL‐b‐PEG by melanoma MEL‐5 cells was also confirmed, with an averaged uptake of 1250(±110) particles cell−1 after incubation for 12 h (50 μg mL−1). This GNR@PCL‐b‐PEG DDS is aimed at addressing the different requirements for therapeutic treatments and is envisaged to provide new insights into DDS targeting for remotely triggered release by NIR activation.
Well‐Defined Flowerlike NdOCl Nanostructures: Nonaqueous Sol–Gel Synthesis, Nanoscale Characterization and Their Magnetic and Photoluminescence Properties
Authors: Li Xinghua , Deng Xia , Zhu Hao , Feng Juan , Peng Yong , Bai Jintao , Zheng Xinliang , Fan Haibo , Wang Mingzi , Chen Haowei 
Published: November 2013

AbstractA facile nonaqueous solution route for the fabrication of NdOCl nanostructures based on a ligand‐exchange protocol and further thermal decomposition in organic medium, using only chloride salt as the neodymium source, is reported and the formation mechanism is proposed. The morphology, crystal structure, and chemical compositions of the sample were characterized at the nanoscale. XRD results and selected‐area electron diffraction patterns show that the sample is purely tetragonal NdOCl without any other impurity phases. TEM results show that the NdOCl nanostructures have a well‐defined flowerlike shape, which looks like a chrysanthemum just about to bloom. Magnetization measurements reveal that the NdOCl nanoflowers show room‐temperature ferromagnetism. The photoluminescence properties were also studied. These results are significant for fundamental research and promising applications of rare‐earth‐based nanostructures.
Influence of tropical cyclone ‘AILA’ on atmospheric surface layer turbulence and fluxes at Ranchi during its landfall
Authors: Murthy B. S. , Latha R. , Kumar Manoj 
Published: November 2013

AbstractSurface layer turbulent fluxes and normalized wind spectra at Ranchi, India during the landfall of severe cyclonic storm ‘AILA’ are compared with the fair weather spectra. Spectral peaks are shifted to lower frequencies as AILA crosses the coast. Dominant eddy sizes after the landfall are observed to be much higher than those before the landfall especially for u component. Spectral energy during the passage of synoptic disturbance in the vicinity is lesser than that of Kaimal's spectrum owing to mismatch of empirical constant over tropics. Mean vertical velocity is positive (negative) before (after) the landfall, indicating dominance of updrafts (downdrafts).
Fluorescent analogs of trypsin inhibitor SFTI‐1 isolated from sunflower seeds—synthesis and applications
Authors: Lesner Adam , Karna Natalia , Psurski Mateusz , Łęgowska Anna , Wysocka Magdalena , Guzow Katarzyna , Sieradzan Adam , Sieńczyk Marcin , Trzonkowski Piotr , Pikuła Michał , Zieliński Maciej , Kosikowska Paulina , Łukajtis Rałał , Łęgowska Monika , Dębowski Dawid , Wiczk Wiesław , Rolka Krzysztof 
Published: November 2013

ABSTRACTThis article describes the synthesis and enzymatic study of newly synthesized analogs of trypsin inhibitors SFTI‐1 that were fluorescent labeled on their N‐terminal amino groups. Two fluorescent derivatives of benzoxazole (3‐[2‐(4‐diphenylaminophenyl)benzoxazol‐5‐yl]‐l‐alanine–[(4NPh2)Ph]Box‐Ala and 3‐[2‐(2',4',5'‐trimethoxyphenyl)benzoxazol‐5‐yl]‐l‐alanine–[2,4,5‐(OMe)3Ph]Box‐Ala) were used as efficient fluorescent labels. The compounds obtained preserved their inhibitory activity and were efficient inhibitors of bovine trypsin or chymotrypsin. Nevertheless, their association inhibition constants were one or two orders of magnitude lower than those determined for unlabeled monocyclic SFTI‐1 or [Phe5]SFTI‐1, respectively. The conjugates obtained were found to be proteolytically stable in the presence of cognate enzymes. Applying such fluorescent peptides, we were able to investigate enzyme‐inhibitor complex formation using fluorescent techniques. We found that such compounds were rapidly internalized by the fibroblast or cancer cells with no cytotoxic effects. © 2013 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 124–135, 2014.
Natural orifice transluminal endoscopic surgery for intra-abdominal emergency conditions
Authors: Bingener J , Ibrahim-zada I 
Published: November 2013

Abstract

Background
Patient benefits from natural orifice transluminal endoscopic surgery (NOTES) are of interest in acute-care surgery. This review provides an overview of the historical development of NOTES procedures, and addresses their current uses and limitations for intra-abdominal emergency conditions.

Methods
A PubMed search was carried out for articles describing NOTES approaches for appendicectomy, percutaneous gastrostomy, hollow viscus perforation and pancreatic necrosectomy. Pertinent articles were reviewed and data on available outcomes synthesized.

Results
Emergency conditions in surgery tax the patient's cardiovascular and respiratory systems, and fluid and electrolyte balance. The operative intervention itself leads to an inflammatory response and blood loss, thus adding to the physiological stress. NOTES provides a minimally invasive alternative access to the peritoneal cavity, avoiding abdominal wall incisions. A clear advantage to the patient is evident with the implementation of an endoscopic approach to deal with inadvertently displaced percutaneous endoscopic gastrostomy tubes and perforated gastroduodenal ulcer. The NOTES approach appears less invasive for patients with infected pancreatic necrosis, in whom it allows surgical debridement and avoidance of open necrosectomy. Transvaginal appendicectomy is the second most frequently performed NOTES procedure after cholecystectomy. The NOTES concept has provided a change in perspective for intramural and transmural endoscopic approaches to iatrogenic perforations during endoscopy.

Conclusion
NOTES approaches have been implemented in clinical practice over the past decade. Selected techniques offer reduced invasiveness for patients with intra-abdominal emergencies, and may improve outcomes. Steady future development and adoption of NOTES are likely to follow as technology improves and surgeons become comfortable with the approaches.
Damage control surgery for abdominal emergencies
Authors: Weber D G , Bendinelli C , Balogh Z J 
Published: November 2013

Abstract

Background
Damage control surgery is a management sequence initiated to reduce the risk of death in severely injured patients presenting with physiological derangement. Damage control principles have emerged as an approach in non-trauma abdominal emergencies in order to reduce mortality compared with primary definitive surgery.

Methods
A PubMed/MEDLINE literature review was conducted of data available over the past decade (up to August 2013) to gain information on current understanding of damage control surgery for abdominal surgical emergencies. Future directions for research are discussed.

Results
Damage control surgery facilitates a strategy for life-saving intervention for critically ill patients by abbreviated laparotomy with subsequent reoperation for delayed definitive repair after physiological resuscitation. The six-phase strategy (including damage control resuscitation in phase 0) is similar to that for severely injured patients, although non-trauma indications include shock from uncontrolled haemorrhage or sepsis. Minimal evidence exists to validate the benefit of damage control surgery in general surgical abdominal emergencies. The collective published experience over the past decade is limited to 16 studies including a total of 455 (range 3–99) patients, of which the majority are retrospective case series. However, the concept has widespread acceptance by emergency surgeons, and appears a logical extension from pathophysiological principles in trauma to haemorrhage and sepsis. The benefits of this strategy depend on careful patient selection. Damage control surgery has been performed for a wide range of indications, but most frequently for uncontrolled bleeding during elective surgery, haemorrhage from complicated gastroduodenal ulcer disease, generalized peritonitis, acute mesenteric ischaemia and other sources of intra-abdominal sepsis.

Conclusion
Damage control surgery is employed in a wide range of abdominal emergencies and is an increasingly recognized life-saving tactic in emergency surgery performed on physiologically deranged patients.
Unlocked Nucleic Acids with a Pyrene‐Modified Uracil: Synthesis, Hybridization Studies, Fluorescent Properties and i‐Motif Stability
Authors: Perlíková Pavla , Karlsen Kasper K. , Pedersen Erik B. , Wengel Jesper 
Published: November 2013

AbstractThe synthesis of two new phosphoramidite building blocks for the incorporation of 5‐(pyren‐1‐yl)uracilyl unlocked nucleic acid (UNA) monomers into oligonucleotides has been developed. Monomers containing a pyrene‐modified nucleobase component were found to destabilize an i‐motif structure at pH 5.2, both under molecular crowding and noncrowding conditions. The presence of the pyrene‐modified UNA monomers in DNA strands led to decreases in the thermal stabilities of DNA*/DNA and DNA*/RNA duplexes, but these duplexes' thermal stabilities were better than those of duplexes containing unmodified UNA monomers. Pyrene‐modified UNA monomers incorporated in bulges were able to stabilize DNA*/DNA duplexes due to intercalation of the pyrene moiety into the duplexes. Steady‐state fluorescence emission studies of oligonucleotides containing pyrene‐modified UNA monomers revealed decreases in fluorescence intensities upon hybridization to DNA or RNA. Efficient quenching of fluorescence of pyrene‐modified UNA monomers was observed after formation of i‐motif structures at pH 5.2. The stabilizing/destabilizing effect of pyrene‐modified nucleic acids might be useful for designing antisense oligonucleotides and hybridization probes.
D–π–A Structured ZnII‐Porphyrin Dyes with Thiophene Moiety for Highly Efficient Dye‐Sensitized Solar Cells
Authors: Kang Sung Ho , Kang Min Soo , Choi In Taek , Hong Ji Yeoun , Ju Myung Jong , Kim Hwan Kyu 
Published: November 2013

AbstractHerein, we design and synthesize a new D–π–A zinc porphyrin, enveloped with a long alkyl thiophene unit (Th‐ZnP‐CNCOOH, TP), for dye‐sensitized solar cells. The long alkyl‐substituted thiophene unit is incorporated into the porphyrin dye to red‐shift its absorption wavelength. The effects of the alkyl thiophene moiety at the meso‐position of the zinc porphyrin on the optical, electrochemical, and photovoltaic properties of the material are investigated. Dye‐sensitized solar cells (DSSCs) prepared using the new dye, co‐adsorbed with a simply structured organic co‐adsorbent (HC‐A4), are fabricated. The obtained TP/HC‐A4‐sensitized DSSCs exhibit a remarkable enhancement in both short‐circuit current (JSC) and open‐circuit voltage (VOC), relative to the corresponding single‐dye DSSCs, which can be attributed to a combination of the light‐harvesting effect from their complementary absorption behavior and the slow charge‐recombination process. The device based on TP/HC‐A4 co‐sensitization yields: JSC=14.4 mA cm−2, VOC=0.62 V, a fill factor FF=0.75 and an efficiency η=6.7 %. This performance is superior to those of devices containing either TP (η=2.4 %) or HC‐A4 (η=2.8 %), fabricated under the same conditions. The present study indicates that the prevention of dye aggregation, as well as complementary absorption spectra of the porphyrin dyes using co‐sensitizers, are key to improving the device performance.
Climbing the Activity Volcano: Core–Shell Ru@Pt Electrocatalysts for Oxygen Reduction
Authors: Jackson Ariel , Viswanathan Venkatasubramanian , Forman Arnold J. , Larsen Ask H. , Nørskov Jens K. , Jaramillo Thomas F. 
Published: November 2013

AbstractWe outline a systematic approach to develop active catalyst materials for an electrochemical reaction. The strategy allows one to tune binding energies of oxygen reaction intermediates on a catalyst surface by taking advantage of two effects: weakening oxygen binding energies by means of thin‐film overlayers, and strengthening oxygen binding energies through nanoscale effects. By engineering a core–shell nanoparticle morphology with the appropriate dimensions, that is, the thickness of the overlayer and the size of the nanoparticle, bonding properties can be modified to improve the catalytic activity of the core–shell system. We demonstrate the application of this strategy for oxygen reduction by identifying Ru@Pt as a candidate material using density functional theory calculations, and then use these calculations to guide the synthesis of active Ru@Pt core–shell catalysts. The Ru@Pt particles, synthesized using a wet chemical method, exhibit ∼2 times higher specific activity (based on electrochemical active surface area) than state‐of‐the‐art Pt/C from TKK.