bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyoxometalate‐Driven Self‐Assembly of Short Peptides into Multivalent Nanofibers with Enhanced Antibacterial Activity
Authors: Li Jingfang , Chen Zhijun , Zhou Mengcheng , Jing Jiangbo , Li Wen , Wang Yang , Wu Lixin , Wang Liyan , Wang Yanqiu , Lee Myongsoo 
Published: January 2016

AbstractMultivalent peptide nanofibers have attracted intense attention as promising platforms, but the fabrication of those nanofibers is mainly dependent on the spontaneous assembly of β‐sheet peptides. Herein we report an alternative approach to the creation of nanofibers: the polyoxometalate‐driven self‐assembly of short peptides. The resultant nanofibers with concentrated positive charges are excellent multivalent ligands for binding with bacterial cells and thus lead to a salient improvement in bioactivity.
Catalytic Enantioselective Functionalization of Unactivated Terminal Alkenes
Authors: Coombs John R. , Morken James P. 
Published: January 2016

AbstractTerminal alkenes are readily available functional groups which appear in α‐olefins produced by the chemical industry, and they appear in the products of many contemporary synthetic reactions. While the organic transformations that apply to alkenes are amongst the most studied reactions in all of chemical synthesis, the number of reactions that apply to nonactivated terminal alkenes in a catalytic enantioselective fashion is small in number. This Minireview highlights the cases where stereocontrol in catalytic reactions of 1‐alkenes is high enough to be useful for asymmetric synthesis.
Construction of Insulin 18‐mer Nanoassemblies Driven by Coordination to Iron(II) and Zinc(II) Ions at Distinct Sites
Authors: Munch Henrik K. , Nygaard Jesper , Christensen Niels Johan , Engelbrekt Christian , Østergaard Mads , Porsgaard Trine , Hoeg‐Jensen Thomas , Zhang Jingdong , Arleth Lise , Thulstrup Peter W. , Jensen Knud J. 
Published: January 2016

AbstractControlled self‐assembly (SA) of proteins offers the possibility to tune their properties or to create new materials. Herein, we present the synthesis of a modified human insulin (HI) with two distinct metal‐ion binding sites, one native, the other abiotic, enabling hierarchical SA through coordination with two different metal ions. Selective attachment of an abiotic 2,2′‐bipyridine (bipy) ligand to HI, yielding HI–bipy, enabled ZnII‐binding hexamers to SA into trimers of hexamers, [[HI–bipy]6]3, driven by octahedral coordination to a FeII ion. The structures were studied in solution by small‐angle X‐ray scattering and on surfaces with AFM. The abiotic metal ligand had a higher affinity for FeII than ZnII ions, enabling control of the hexamer formation with ZnII and the formation of trimers of hexamers with FeII ions. This precise control of protein SA to give oligomers of oligomers provides nanoscale structures with potential applications in nanomedicine.
Metal Free Bi(hetero)aryl Synthesis: A Benzyne Truce–Smiles Rearrangement
Authors: Holden Catherine M. , Sohel Shariar M. A. , Greaney Michael F. 
Published: January 2016

AbstractA new benzyne transformation is described that affords versatile biaryl structures without recourse to transition‐metal catalysis or stoichiometric amounts of organometallic building blocks. Aryl sulfonamides add to benzyne upon fluoride activation, and then undergo an aryl Truce–Smiles rearrangement to afford biaryls with sulfur dioxide extrusion. The reaction proceeds under simple reaction conditions and has excellent scope for the synthesis of sterically hindered atropisomeric biaryl amines.
Enantioselective Total Synthesis of Terreumols A and C from the Mushroom Tricholoma terreum
Authors: Frichert Alex , Jones Peter G. , Lindel Thomas 
Published: January 2016

AbstractThe cytotoxic meroterpenoids terreumol A and C from the grey knight mushroom Tricholoma terreum were synthesized for the first time. The key step of the enantioselective total synthesis of terreumol C is a ring‐closing metathesis to form a trisubstituted Z double bond embedded in the 10‐membered ring of the [8.4.0] bicycle. Interestingly, the presence of a free hydroxy group in the metathesis precursor prevents cyclization and favors cross metathesis. (−)‐Terreumol C was converted into (−)‐terreumol A by diastereoselective epoxidation. Starting from 2‐bromo‐3,5‐dimethoxybenzaldehyde, 14 steps with an overall yield of 23 % are needed for the synthesis of (−)‐terreumol A. X‐ray analysis of the benzoquinone analogue of terreumol A provides independent proof of the absolute configuration.
Total Synthesis of Isodaphlongamine H: A Possible Biogenetic Conundrum
Authors: Chattopadhyay Amit Kumar , Ly Vu Linh , Jakkepally Shashidhar , Berger Gilles , Hanessian Stephen 
Published: January 2016

AbstractHerein we describe the first synthetic efforts toward the total synthesis of isodaphlongamine H, a calyciphylline B‐type alkaloid. The strategy employs a chemoenzymatic process for the preparation of a functionalized cyclopentanol with a quaternary center. This molecule is elaborated to form an enantiopure 1‐aza‐perhydrocyclopentalene core, representing rings A and E of all calyciphylline B‐type alkaloids. Further transformations involve the formation of a cyclic enaminone, 1,4‐conjugate addition with a cyclopentenyl subunit, and intramolecular aldol cyclization to achieve a pentacyclic intermediate, ultimately forming isodaphlongamine H in a total of 24 steps from the commercially available compound 2‐carbethoxycyclopentanone. Isodaphlongamine H exhibits promising inhibitory activity against a panel of human cancer cell lines.
Nitrogen‐Doped Graphene for Photocatalytic Hydrogen Generation
Authors: Chang Dong Wook , Baek Jong‐Beom 
Published: January 2016

AbstractPhotocatalytic hydrogen (H2) generation in a water splitting process has recently attracted tremendous interest because it allows the direct conversion of clean and unlimited solar energy into the ideal energy resource of H2. For efficient photocatalytic H2 generation, the role of the photocatalyst is critical. With increasing demand for more efficient, sustainable, and cost‐effective photocatalysts, various types of semiconductor photocatalysts have been intensively developed. In particular, on the basis of its superior catalytic and tunable electronic properties, nitrogen‐doped graphene is a potential candidate for a high‐performance photocatalyst. Nitrogen‐doped graphene also offers additional advantages originating from its unique two‐dimensional sp2‐hybridized carbon network including a large specific surface area and exceptional charge transport properties. It has been reported that nitrogen‐doped graphene can play diverse but positive functions including photo‐induced charge acceptor/meditator, light absorber from UV to visible light, n‐type semiconductor, and giant molecular photocatalyst. Herein, we summarize the recent progress and general aspects of nitrogen‐doped graphene as a photocatalyst for photocatalytic H2 generation. In addition, challenges and future perspectives in this field are also discussed.
MapMaker and PathTracer for tracking carbon in genome‐scale metabolic models
Authors: Tervo Christopher J. , Reed Jennifer L. 
Published: January 2016

AbstractConstraint‐based reconstruction and analysis (COBRA) modeling results can be difficult to interpret given the large numbers of reactions in genome‐scale models. While paths in metabolic networks can be found, existing methods are not easily combined with constraint‐based approaches. To address this limitation, two tools (MapMaker and PathTracer) were developed to find paths (including cycles) between metabolites, where each step transfers carbon from reactant to product. MapMaker predicts carbon transfer maps (CTMs) between metabolites using only information on molecular formulae and reaction stoichiometry, effectively determining which reactants and products share carbon atoms. MapMaker correctly assigned CTMs for over 97% of the 2,251 reactions in an Escherichia coli metabolic model (iJO1366). Using CTMs as inputs, PathTracer finds paths between two metabolites. PathTracer was applied to iJO1366 to investigate the importance of using CTMs and COBRA constraints when enumerating paths, to find active and high flux paths in flux balance analysis (FBA) solutions, to identify paths for putrescine utilization, and to elucidate a potential CO2 fixation pathway in E. coli. These results illustrate how MapMaker and PathTracer can be used in combination with constraint‐based models to identify feasible, active, and high flux paths between metabolites.
Exploring mild enzymatic sustainable routes for the synthesis of bio‐degradable aromatic‐aliphatic oligoesters
Authors: Pellis Alessandro , Guarneri Alice , Brandauer Martin , Acero Enrique Herrero , Peerlings Henricus , Gardossi Lucia , Guebitz Georg M. 
Published: January 2016

AbstractThe application of Candida antarctica lipase B in enzyme‐catalyzed synthesis of aromatic‐aliphatic oligoesters is here reported. The aim of the present study is to systematically investigate the most favorable conditions for the enzyme catalyzed synthesis of aromatic‐aliphatic oligomers using commercially available monomers. Reaction conditions and enzyme selectivity for polymerization of various commercially available monomers were considered using different inactivated/activated aromatic monomers combined with linear polyols ranging from C2 to C12. The effect of various reaction solvents in enzymatic polymerization was assessed and toluene allowed to achieve the highest conversions for the reaction of dimethyl isophthalate with 1,4‐butanediol and with 1,10‐decanediol (88 and 87% monomer conversion respectively). Mw as high as 1512 Da was obtained from the reaction of dimethyl isophthalate with 1,10‐decanediol. The obtained oligomers have potential applications as raw materials in personal and home care formulations, for the production of aliphatic‐aromatic block co‐polymers or can be further functionalized with various moieties for a subsequent photo‐ or radical polymerization.
Contribution of domain 30 of tropoelastin to elastic fiber formation and material elasticity
Authors: Muiznieks Lisa D. , Miao Ming , Sitarz Eva E. , Keeley Fred W. 
Published: January 2016

ABSTRACTElastin is a fibrous structural protein of the extracellular matrix that provides reversible elastic recoil to vertebrate tissues such as arterial vessels, lung, and skin. The elastin monomer, tropoelastin, contains a large proportion of intrinsically disordered and flexible hydrophobic sequences that collectively are responsible for the initial phase separation of monomers during assembly, and are essential for driving elastic recoil. While structural disorder of hydrophobic sequences is controlled by a high proline and glycine residue composition, hydrophobic domain 30 of human tropoelastin is atypically proline‐poor, and forms β‐sheet amyloid‐like fibrils as an individual peptide. We explored the contribution of confined regions of secondary structure at the location of domain 30 in human tropoelastin to fiber assembly and mechanical properties using a set of mutations designed to inhibit or enhance the propensity of β‐sheet formation at this location. Our data support a dual role for confined β‐sheet secondary structure in domain 30 of tropoelastin in guiding the formation of fibers, and as a determinant of stiffness and viscoelastic properties of cross‐linked materials. Together, these results suggest a mechanism for specificity in fiber assembly, and elucidate structure‐function relationships for the rational design of elastomeric biomaterials with defined mechanical properties. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 267–275, 2016.
The use of an imagery mnemonic to teach the Krebs cycle
Authors: Morisaki Ryoma , Bon Charles , Levitt Jacob O. 
Published: January 2016

AbstractThe Krebs Cycle is a highly taught biochemical pathway that is traditionally difficult to learn. Twenty‐seven undergraduate students were randomized to a rote memorization arm or to a mnemonic arm. They were given a pre‐test, then shown a lecture corresponding to their assigned method, and then given an immediate Week 0 post‐test and a Week 4 post‐test. Groups scored comparably low on the pre‐test (p = 0.7113). Students in the mnemonic arm performed better on the Week 0 post‐test than those using rote (p = 0.0055). By Week 4, there was evidence of knowledge decay, with both arms' having comparably low scores (mnemonic vs. rote, p = 0.3739). The mnemonic assists in rapid acquisition of knowledge but probably has to be reviewed iteratively over time to demonstrate its full potential over rote memorization. A limited number of students from only one school was used. © 2016 by The International Union of Biochemistry and Molecular Biology, 44:224–229, 2016.
Prospective evaluation of radiation‐induced skin toxicity in a race/ethnically diverse breast cancer population
Authors: Wright Jean L. , Takita Cristiane , Reis Isildinha M. , Zhao Wei , Lee Eunkyung , Nelson Omar L. , Hu Jennifer J. 
Published: January 2016

AbstractWe evaluated predictors of radiation‐induced skin toxicity in a prospective study of a tri‐racial/ethnic breast cancer population. We evaluated patient demographics, tumor characteristics, and treatment variables in the first 392 patients in a prospective study assessing radiation‐induced skin toxicity. Logistic regression analyses were conducted to evaluate potential predictors of skin toxicity. The study consists of 59 non‐Hispanic whites (NHW; 15%), 241 Hispanic Whites (HW; 62%), 79 black or African Americans (AA; 20%), and 13 others (3%). Overall, 48% developed grade 0–1 skin toxicity, 49.8% grade 2, and 2.2% grade 3 by the National Cancer Institute's Common Toxicity Criteria for Adverse Events (CTCAE) scale. Twenty‐one percent developed moist desquamation. In multivariate analysis, higher body mass index (BMI; OR = 2.09; 95%CI = 1.15, 3.82), higher disease stage (OR = 1.82; 95%CI = 1.06, 3.11), ER‐positive/PR‐negative status (OR = 2.74; 95%CI = 1.26, 5.98), and conventionally fractionated regimens (OR = 3.25; 95%CI = 1.76, 6.01) were significantly associated with higher skin toxicity grade after adjustment for age, race, ethnicity, ER status, and breast volume. BMI specifically predicted for moist desquamation, but not degree of erythema. In this racially and ethnically diverse cohort of breast cancer patients receiving radiation to the intact breast, risk factors including BMI, disease stage, and conventionally fractionated radiation predicted for higher skin toxicity grade, whereas age, race, ethnicity, and breast volume did not. BMI specifically predicted for moist desquamation, suggesting that preventive measures to address this particular outcome should be investigated.
Marine Pyridoacridine Alkaloids: Biosynthesis and Biological Activities
Authors: Ibrahim Sabrin R. M. , Mohamed Gamal A. 
Published: January 2016

AbstractPyridoacridines are a class of strictly marine‐derived alkaloids that constitute one of the largest chemical families of marine alkaloids. During the last few years, both natural pyridoacridines and their analogues have constituted excellent targets for synthetic works. They have been the subject of intense study due to their significant biological activities; cytotoxic, antibacterial, antifungal, antiviral, insecticidal, anti‐HIV, and anti‐parasitic activities. In the present review, 95 pyridoacridine alkaloids isolated from marine organisms are discussed in term of their occurrence, biosynthesis, biological activities, and structural assignment.
The safety and effectiveness of bivalirudin in female patients with acute myocardial infarction undergoing primary angioplasty: A subgroup analysis of the BRIGHT trial
Authors: Liang Zhenyang , Li Yi , Wang Jingping , Wang Dongmei , Wang Shouli , Ma Likun , Liu Huiliang , Yang Lixia , Stone Gregg W. , Han Yaling 
Published: January 2016

BackgroundBeing female is an independent predictor of adverse events during percutaneous coronary interventions (PCI).ObjectiveTo evaluate the safety and efficiency of bivalirudin during emergency PCI in female patients with acute myocardial infarction (AMI).MethodsThe present study was a subgroup analysis of the randomized Bivalirudin in Acute Myocardial Infarction vs. Heparin and GPI plus Heparin (BRIGHT) trial. A total of 392 female patients enrolled in the BRIGHT trial were assigned to receive bivalirudin with post‐procedure dose infusion (n = 127) or heparin with or without tirofiban (n = 265). The primary efficiency endpoint was 30‐day net adverse clinical events (NACEs). The secondary efficiency endpoints were 30‐day major cardiac and cerebral events (MACCEs) and bleeding events defined according to Bleeding Academic Research Consortium (BARC) definitions.ResultsFor female patients, bivalirudin treatment was associated with significantly lower incidences of 30‐day NACEs (6.3% vs. 21.5%, P < 0.001), any bleeding (2.4% vs. 12.8%, P = 0.001) and BARC 2–5 type bleeding (1.6% vs. 7.2%, P = 0.021) compared with the control regimen. The incidence of MACCEs (3.4% vs. 9.4%, P = 0.055) and stent thrombosis (0% vs. 1.1%, P = 0.229) were comparable between the two groups. Multivariate analysis showed that bivalirudin (OR: 0.245, 95% CI: 0.113–0.532, P < 0.001), transradial access (OR: 0.119, 95% CI: 0.067–0.211, P < 0.001), and statin (OR: 0.254, 95% CI: 0.08–0.807, P = 0.02) were independent protective factors for 30‐day NACEs in female patients.ConclusionsThe use of bivalirudin during emergency PCI for AMI in female patients significantly reduced the bleeding risk with anticoagulation effects compared with heparin with or without tirofiban. © 2016 Wiley Periodicals, Inc.
Enhanced Ene‐Reductase Activity through Alteration of Artificial Nicotinamide Cofactor Substituents
Authors: Löw Sebastian A. , Löw Isabell M. , Weissenborn Martin J. , Hauer Bernhard 
Published: January 2016

AbstractThe reduction of activated C=C double bonds is an important reaction in synthetic chemistry owing to the potential formation of up to two new stereogenic centers. Artificial nicotinamide cofactors were recently presented as alternative suppliers of hydride equivalents needed for alkene reduction. To study the effect of cofactors on the reduction of activated alkenes, a set of N‐substituted synthetic nicotinamide cofactors with differing oxidation potentials were synthesized and their electrochemical and kinetic behavior was studied. The effects of the synthetic cofactors on enzyme activity of four ene reductases are outlined in this study, where the cofactor mimic with an N‐substituted 4‐hydroxy‐phenyl residue led to a sixfold higher vmax relative to the natural cofactor NADH.
Uniform Two‐Dimensional Co3O4 Porous Sheets: Facile Synthesis and Enhanced Photocatalytic Performance
Authors: Liu Jiangyong , Wang Dan , Wang Min , Kong Dejia , Zhang Yi , Chen Jian‐Feng , Dai Liming 
Published: January 2016

AbstractThe preparation of high‐quality two‐dimensional materials with highly interesting properties and applications, such as graphene and graphene analogues, is a rapidly expanding research area. Herein, two‐dimensional porous Co3O4 sheets with high uniformity were synthesized via a facile hydrothermal route. Various characterizations were performed to investigate this sheet‐like structure. Owing to the desired promotion effects and multiple functionalities derived from this unique structure, the porous Co3O4 sheets present an enhanced photocatalytic performance in comparison with the bulk Co3O4 powder.
Transition‐Metal‐Mediated Cleavage of Fluoro‐Silanes under Mild Conditions
Authors: Kameo Hajime , Kawamoto Tatsuya , Sakaki Shigeyoshi , Bourissou Didier , Nakazawa Hiroshi 
Published: January 2016

AbstractSi−F bond cleavage of fluoro‐silanes was achieved by transition‐metal complexes under mild and neutral conditions. The Iridium‐hydride complex [Ir(H)(CO)(PPh3)3] was found to readily break the Si−F bond of the diphosphine‐ difluorosilane {(o‐Ph2P)C6H4}2Si(F)2 to afford a silyl complex [{[o‐(iPh2P)C6H4]2(F)Si}Ir(CO)(PPh3)] and HF. Density functional theory calculations disclose a reaction mechanism in which a hypervalent silicon species with a dative Ir→Si interaction plays a crucial role. The Ir→Si interaction changes the character of the H on the Ir from hydridic to protic, and makes the F on Si more anionic, leading to the formation of Hδ+⋅⋅⋅Fδ− interaction. Then the Si−F and Ir−H bonds are readily broken to afford the silyl complex and HF through σ‐bond metathesis. Furthermore, the analogous rhodium complex [Rh(H)(CO)(PPh3)3] was found to promote the cleavage of the Si−F bond of the triphosphine‐monofluorosilane {(o‐Ph2P)C6H4}3Si(F) even at ambient temperature.
Fine Substituent Effects in Sandwich Complexes: A Threshold Ionization Study of Monosubstituted Chromium Bisarene Compounds
Authors: Ketkov Sergey Yu. , Markin Gennady V. , Tzeng Sheng Y. , Tzeng Wen B. 
Published: January 2016

AbstractMass‐analyzed threshold ionization spectra of jet‐cooled [(η6‐PhMe)(η6‐PhH)Cr] and [(η6‐Ph2)(η6‐PhH)Cr] reveal with unprecedented accuracy the effects of methyl and phenyl groups on the electronic structure of bis(η6‐benzene)chromium. These “pure” substituent effects allow quantitative experimental determination of the ionization energy changes caused by the mutual substituent influence in bisarene systems. Two types of such influence have been revealed for the first time in bis(η6‐toluene)chromium.
ChemInform Abstract: [TM13@Bi20]‐ Clusters in Three‐Shell Icosahedral Matryoshka Structure: Being as Superatoms.
Authors: Kou C. Y. , Zhuang L. , Wang G. Q. , Cui H. , Yuan H. K. , Tian C. L. , Wang J. Z. , Chen H. 
Published: January 2016

AbstractUsing the DFT method the 33‐atom intermetalloid [M13@Bi20]‐ clusters (M: 3d, 4d transition metals) which are composed of Bi20 pentagonal dodecahedra surrounded by M12 icosahedra with a single M atom at the center are systematically examined to explore the possibility of the clusters being superatoms.
ChemInform Abstract: Structural and Crystal Chemical Properties of Alkali Rare‐Earth Double Phosphates.
Authors: Farmer J. Matt , Boatner L. A. , Chakoumakos Bryan C. , Rawn Claudia J. , Richardson Jim 
Published: January 2016

AbstractCrystals of K3Ln(PO4)2 (Ln: Lu, Yb, Er, Ho, Dy, Gd, Nd, Ce, Y, Sc) and M3Lu(PO4)2 (M: Rb, Cs) are prepared from a M4P2O7/Ln2O3 flux (Pt crucible, 1235 °C, 4 h) and their crystal structures are determined by single crystal XRD and powder neutron diffraction.
ChemInform Abstract: Crystal Structures of Cristobalite‐Type and Coesite‐Type PON Redetermined on the Basis of Single‐Crystal X‐Ray Diffraction Data.
Authors: Bykov Maxim , Bykova Elena , Dyadkin Vadim , Baumann Dominik , Schnick Wolfgang , Dubrovinsky Leonid , Dubrovinskaia Natalia 
Published: January 2016

AbstractSingle crystals of cristobalite‐type PON (cri‐PON) are prepared by a two‐step condensation process starting with the reaction of POCl3 and liq.
ChemInform Abstract: A High‐Performance Electrocatalyst for Oxygen Evolution Reaction: LiCo0.8Fe0.2O2.
Authors: Zhu Yinlong , Zhou Wei , Chen Yubo , Yu Jie , Liu Meilin , Shao Zongping 
Published: January 2016

AbstractLayered LiCo1‐xFexO2 (x = 0—1) is prepared by sol‐gel processing applying stoichiometric amounts of metal nitrates and EDTA and citric acid in molar ratios of 1:1:2 at pH≈6.
ChemInform Abstract: Enantio‐ & Chemo‐Selective Preparation of Enantiomerically Enriched Aliphatic Nitro Alcohols Using Candida parapsilosis ATCC 7330.
Authors: Venkataraman Sowmyalakshmi , Chadha Anju 
Published: January 2016

AbstractThe title biocatalyst mediates the asymmetric, chemoselective reduction of nitroketones wherein the keto group is preferred with respect to the nitro group.
ChemInform Abstract: Copper‐Catalyzed Asymmetric Conjugate Addition of Dimethylzinc to Acyl‐N‐methylimidazole Michael Acceptors: A Powerful Synthetic Platform.
Authors: Drissi‐Amraoui Sammy , Morin Marie S. T. , Crevisy Christophe , Basle Olivier , Marcia de Figueiredo Renata , Mauduit Marc , Campagne Jean‐Marc 
Published: January 2016

AbstractThe enantioselective addition of dimethylzinc to α,β‐unsaturated ketones of type (I) in the presence of Cu(OTf)2 and the chiral NHC (IMD) as catalysts affords the corresponding 1,4‐adducts (III) in high regio‐ and enantioselectivities.