bluuebunny/crossref_metadata_2025 huggingface dataset:
Particle Accretion Mechanism Underlies Biological Crystal Growth from an Amorphous Precursor Phase
Authors: Gal Assaf , Kahil Keren , Vidavsky Netta , DeVol Ross T. , Gilbert Pupa U. P. A. , Fratzl Peter , Weiner Steve , Addadi Lia
Published: July 2014

Many biogenic minerals are composed of aggregated particles at the nanoscale. These minerals usually form through the transformation of amorphous precursors into single crystals inside a privileged space controlled by the organism. Here, in vitro experiments aimed at understanding the factors responsible for producing such single crystals with aggregated particle texture are presented. Crystallization is achieved by a two‐step reaction in which amorphous calcium carbonate (ACC) is first precipitated and then transformed into calcite in small volumes of water and in the presence of additives. The additives used are gel‐forming molecules, phosphate ions, and the organic extract from sea urchin embryonic spicules ‐ all are present in various biogenic crystals that grow via the transformation of ACC. Remarkably, this procedure yields faceted single‐crystals of calcite that maintain the nanoparticle texture. The crystals grow predominantly by the accretion of ACC nanoparticles, which subsequently crystallize. Gels and phosphate ions stabilize ACC via a different mechanism than sea urchin spicule macromolecules. It is concluded that the unique nanoparticle texture of biogenic minerals results from formation pathways that may differ from one another, but given the appropriate precursor and micro‐environment, share a common particle accretion mechanism.
Continuous electroreduction of CO2 to formate using Sn gas diffusion electrodes
Authors: Del Castillo Andrés , Alvarez‐Guerra Manuel , Irabien Angel
Published: July 2014

Electrochemical valorization may be a strategy for mitigating climate change, as the process allows for CO2 to be converted into industrially useful chemicals. The aim of this work is to study the influence of key variables on the performance of an experimental system for continuous electroreduction of CO2 to formate with a gas diffusion electrode (GDE) loaded with Sn. A 23 factorial design of experiments at different levels of current density (j), electrolyte flow rate/electrode area ratio (Q/A ratio) and GDE Sn load was followed. Higher rates and concentrations (i.e., 1.4·10−3 mol m−2 s−1 and 1348 mg L−1 with efficiencies of approximately 70%) were obtained with GDEs than with plate electrodes. The statistical design of experiments demonstrated that the Sn load had the most significant effect on rate and efficiency. However, despite these promising results, further research is required to optimize the process. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3557–3564, 2014
Kinetics of CO2 absorption by aqueous 3‐(methylamino)propylamine solutions: Experimental results and modeling
Authors: Monteiro Juliana G. M.‐S. , Hussain Saddam , Majeed Hammad , Mba Emmanuel O. , Hartono Ardi , Knuutila Hanna , Svendsen Hallvard F.
Published: July 2014

Experimental data and a model for the initial kinetics of CO2 into 3‐(methylamino)propylamine (MAPA) solutions are presented in work. MAPA has been tested as an activator for tertiary amines with encouraging results. The measurements were performed in a string of discs contactor and, as no initial kinetics data are available in literature, additional measurements were carried out and in a wetted wall column. The obtained overall mass‐transfer coefficients from both apparatuses are in reasonable agreement. To obtain values for the observed kinetic constant,
, the experimental results were interpreted using a two‐film mass‐transfer model and invoking the pseudo‐first order assumption. Needed experimental values for density, viscosity, and Henry's law coefficient for CO2 were measured and are given. The results indicate that MAPA is almost twice as fast as piperazine, eight times faster than 2‐(2‐aminoethyl‐amino)ethanol (AEEA), and 15 times faster than monoethanolamine, when comparing unloaded 1 M solutions at 25°C. The observed kinetic constant was modeled using the direct mechanism. The final expression for
can be applied for any concentration and temperature within the experimental data range, and, together with the presented physical data, comprises a complete model for calculating absorption fluxes. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3792–3803, 2014
Stuve–Wiedemann syndrome: Is it underrecognized?
Authors: Yeşil Gözde , Lebre Anne Sophie , Santos Sofia Dos , Güran Ömer , Özahi Ilke Ipek , Daire Valeria Cormier , Güran Tülay
Published: July 2014

Stuve–Wiedemann Syndrome (SWS) (OMIM #601559) is an autosomal recessive disorder characterized by skeletal changes, bowing of the lower limb, severe osteoporosis and joint contractures, episodic hyperthermia, frequent respiratory infections, feeding problems and high mortality in early life. It is caused by mutation in the leukemia inhibitory factor receptor gene (LIFR; 151443) on chromosome 5p13. We provide the clinical follow‐up and molecular aspects of six new patients who carried the same novel mutation in the LIFR gene (p.Arg692X) and three patients carried a common haplotype at the LIFR locus supporting a founder effect in the Turkish population. The probable pathogenesis of the features is also discussed. Osseous findings in the presence of other above‐mentioned morbid conditions should raise the suspicion of SWS in neonates especially in Arabic and Eastern Mediterranean countries with high rate of consanguineous marriages like in Turkey. Severe osteoporosis, bone deformities, milias, leukocoria, inflammatory lesions on distal extremities, tongue biting behavior and oral ulcers could be more prominent features of the survivors beyond the neonatal period while respiratory and feeding problems are remitting. It is of crucial importance to diagnose such babies earlier in order to prevent extensive laboratory workup and to provide proper genetic counseling. © 2014 Wiley Periodicals, Inc.
Multicentric carpotarsal osteolysis syndrome is caused by only a few domain‐specific mutations in MAFB, a negative regulator of RANKL‐induced osteoclastogenesis
Authors: Mumm Steven , Huskey Margaret , Duan Shenghui , Wenkert Deborah , Madson Katherine L. , Gottesman Gary S. , Nenninger Angela R. , Laxer Ronald M. , McAlister William H. , Whyte Michael P.
Published: July 2014

Multicentric carpotarsal osteolysis syndrome (MCTO), an autosomal dominant disorder that often presents sporadically, features carpal–tarsal lysis frequently followed by nephropathy and renal failure. In 2012, mutations in the single‐exon gene MAFB were reported in 13 probands with MCTO. MAFB is a negative regulator of RANKL‐mediated osteoclastogenesis. We studied nine MCTO patients (seven sporadic patients and one affected mother and son) for MAFB mutation. We PCR‐amplified and selectively sequenced the MAFB region that contains the transactivation domain in this 323 amino acid protein, where mutations were previously reported for MCTO. We found five different heterozygous missense defects among eight probands: c.176C > T, p.Pro59Leu; c.185C > T, p.Thr62Ile; c.206C > T, p.Ser69Leu (four had this defect); c.209C > T, p.Ser70Leu; and c.211C > T, p.Pro71Ser. All 5 mutations are within a 13 amino acid stretch of the transactivation domain. Four were identical to the previously reported mutations. Our unique mutation (c.185C > T, p.Thr62Ile) involved the same domain. DNA available from seven parents of the seven sporadic patients did not show their child's MAFB mutation. The affected mother and son had an identical defect. Hence, the mutations for 7/8 probands were suspected to have arisen spontaneously as there was no history of features of MCTO in either parent. Penetrance of MCTO seemed complete. Lack of nonsense or other truncating mutations suggested a dominant‐negative pathogenesis. Our findings indicate that only a few transactivation domain‐specific mutations within MAFB cause MCTO. © 2014 Wiley Periodicals, Inc.
Are 22q11.2 distal deletions associated with math difficulties?
Authors: Carvalho Maria Raquel Santos , Vianna Gabrielle , Oliveira Lívia de Fátima Silva , Costa Annelise Julio , Pinheiro‐Chagas Pedro , Sturzenecker Rosane , Zen Paulo Ricardo Gazzola , Rosa Rafael Fabiano Machado , de Aguiar Marcos José Burle , Haase Vitor Geraldi
Published: July 2014

Approximately 6% of school‐aged children have math difficulties (MD). A neurogenetic etiology has been suggested due to the presence of MD in some genetic syndromes such as 22q11.2DS. However, the contribution of 22q11.2DS to the MD phenotype has not yet been investigated. This is the first population‐based study measuring the frequency of 22q11.2DS among school children with MD. Children (1,564) were identified in the schools through a screening test for language and math. Of these children, 152 (82 with MD and 70 controls) were selected for intelligence, general neuropsychological, and math cognitive assessments and for 22q11.2 microdeletion screening using MLPA. One child in the MD group had a 22q11.2 deletion spanning the LCR22‐4 to LCR22‐5 interval. This child was an 11‐year‐old girl with subtle anomalies, normal intelligence, MD attributable to number sense deficit, and difficulties in social interactions. Only 19 patients have been reported with this deletion. Upon reviewing these reports, we were able to characterize a new syndrome, 22q11.2 DS (LCR22‐4 to LCR22‐5), characterized by prematurity; pre‐ and postnatal growth restriction; apparent hypotelorism, short/upslanting palpebral fissures; hypoplastic nasal alae; pointed chin and nose; posteriorly rotated ears; congenital heart defects; skeletal abnormalities; developmental delay, particularly compromising the speech; learning disability (including MD, in one child); intellectual disability; and behavioral problems. These results suggest that 22q11.2 DS (LCR22‐4 to LCR22‐5) may be one of the genetic causes of MD. © 2014 Wiley Periodicals, Inc.
Atypical Aicardi‐Goutieres syndrome: Is the WRN locus a modifier?
Authors: Lessel Davor , Saha Bidisha , Hisama Fuki , Kaymakamzade Bahar , Nurlu Gulay , Gursoy‐Özdemir Yasemin , Thiele Holger , Nürnberg Peter , Martin George M. , Kubisch Christian , Oshima Junko
Published: July 2014

We describe a 28‐year‐old Turkish man with consanguineous parents who presented with an aged appearance with prematurely gray hair and scleroderma‐like skin, spastic paraplegia, and apparent disability. The proband and each of his parents were heterozygous for a mutation in WRN, which could not explain his symptoms. Exome sequencing of the proband's blood DNA showed a homozygous c.626‐1G > C mutation in intron 5 of the SAMHD1 gene, which encodes a triphosphohydrolase involved in the regulation of intracellular dNTP pools and which is mutated in Aicardi‐Goutieres syndrome. The RNA studies confirmed aberrant splicing of exon 6, and family studies showed that both parents are heterozygous for this mutation. We conclude that mutations in SAMHD1 ‐ in addition to causing an early‐onset form of encephalopathy in Aicardi‐Goutieres syndrome ‐ may present with modest signs of accelerated aging similar to Werner syndrome. The extent to which heterozygosity at the WRN locus may modify the effect of biallelic SAMHD1 mutations is unknown. It is conceivable that synergistic effects of these two mutations might be responsible for the unusual phenotype. © 2014 Wiley Periodicals, Inc.
A Practical Approach for the Oxidation of Unactivated Csp3H Bonds with o‐Nitro(diacetoxyiodo)benzene as an Efficient Hypervalent Iodine(III)‐Based Oxidizing Agent
Authors: Moteki Shin A. , Selvakumar Sermadurai , Zhang Tiexin , Usui Asuka , Maruoka Keiji
Published: July 2014

A practical approach for the oxidation of unactivated Csp3H bonds by an ortho‐nitrophenyl‐substituted hypervalent iodine(III) reagent is presented. The nitro group coordinates to the adjacent iodine center through dipolar interaction, which leads to a single substitution of the acetate ligand by tert‐butyl hydroperoxide. As a result, a strong iodanyl radical is formed, which can activate the inert Csp3H bonds in a highly efficient manner. The reagent is stable in the presence of moisture, and can be used for oxidation reactions on semipreparative scale.
Nasal fluid release of eotaxin‐3 and eotaxin‐2 in persistent sinonasal eosinophilic inflammation
Authors: De Corso Eugenio , Baroni Silvia , Battista Mariapina , Romanello Matteo , Penitente Romina , Di Nardo Walter , Passali Giulio Cesare , Sergi Bruno , Fetoni Anna Rita , Bussu Francesco , Zuppi Cecilia , Paludetti Gaetano
Published: July 2014

Background

The aim of the present study was to measure eotaxin‐3 (CCL26) and eotaxin‐2 (CCL24) in nasal lavage fluid of patients with different forms of chronic sinonasal eosinophilic inflammation to evaluate their role in the pathophysiology of nasal hypereosinophilia.

Methods

The study was an analytic cross‐section study, level of evidence 3b. Patients (n = 80) with nasal hypereosinophilia were randomly recruited and grouped in the following categories: persistent allergic rhinitis (AR) (n = 25), nonallergic rhinitis with eosinophilia syndrome (NARES) (n = 30), and chronic rhinosinusitis with polyps (CRSwNP) (n = 25). Non‐rhinitic volunteers (n = 20) were recruited as controls. CCL24 and CCL26 concentrations were measured by enzyme‐linked immunosorbent assay (ELISA) Quantikine Human Immunoassays (R&D Systems, Minneapolis, MN) in nasal lavage fluids. Differential cell counts were performed by microscopic cytological examination of nasal tissue scraped from the inferior turbinate.

Results

Mean CCL26 levels were significantly higher (p < 0.05) in AR and in NARES (132.0 pg/mL and 187.63 pg/mL, respectively) than in the control group (13.5 pg/mL); in patients with CRSwNP, CCL26 values were increased compared to controls even though the difference was not statistically significant (58.9 pg/mL vs 16.5 pg/mL). Mean CCL24 levels measured in AR, NARES, and CRSwNP were significantly increased (p < 0.05) compared to controls (96.7 pg/mL, 135.4 pg/mL, and 107.0 pg/mL, respectively, vs 32.2 pg/mL). Moreover, we observed a significant correlation between CCL24 and CCL26 levels, evaluating them intraindividually by Spearman's rank correlation test. Finally, a significant correlation was found between CCL24 and CCL26 levels and the percentage of eosinophilic infiltration of nasal mucosa.

Conclusion

Our data suggest that CCL26 and CCL24 are likely involved in the pathogenesis of chronic nasal hypereosinophilia, with a complex cooperation and different involvement of the various members of eotaxin family. Further studies are necessary to better understand the actual physiopathologic mechanism, possible clinical relevance, and therapeutic implications.
A novel magnetic resonance imaging approach to collateral flow imaging in ischemic stroke
Authors: Kim Suk Jae , Son Jeong Pyo , Ryoo Sookyung , Lee Mi‐Ji , Cha Jihoon , Kim Keon Ha , Kim Gyeong‐Moon , Chung Chin‐Sang , Lee Kwang Ho , Jeon Pyoung , Bang Oh Young
Published: July 2014

Objective

Dedicated magnetic resonance (MR) imaging (MRI) sequences for evaluation of collaterals can be generated using MR perfusion (MRP) source data. We compared a novel collateral flow imaging technique with digital subtraction angiography (DSA) for determining collateral circulation in acute stroke and evaluated the ability of MR‐based collateral flow maps to predict outcomes after recanalization therapy.

Methods

Consecutive patients who were candidates for endovascular treatment were enrolled. A collateral flow map derived from MRP source data was generated by manual or automatic postprocessing. Collateral grading based on the collateral flow map was performed and compared with grading based on DSA. Clinical and radiological outcomes were evaluated according to MR‐based collateral grading and early reperfusion (ER) status.

Results

There was good correlation between MRI‐based and DSA‐based collateral grades (weighted κ‐coefficient = 0.70). Collateral status and achievement of ER were the 2 main determinants of a favorable functional outcome and neurological improvement, in addition to infarct growth. Regardless of achievement of ER, better collaterals were significantly associated with a lower modified Rankin score at day 90 (p < 0.001 for trend in both ER− and ER+). Most symptomatic intracranial hemorrhages occurred in patients with a poor collateral grade and ER+, whereas no patient with excellent collaterals suffered symptomatic intracranial hemorrhage or died.

Interpretation

MRI techniques to assess collaterals are rapidly being developed, and may provide insight into collateral perfusion. The combination of collateral images derived from pretreatment MRP source data and reperfusion status is a robust predictor of outcomes in acute ischemic stroke. Ann Neurol 2014;76:356–369
Collisional and Coulombic Unfolding of Gas‐Phase Proteins: High Correlation to Their Domain Structures in Solution
Authors: Zhong Yueyang , Han Linjie , Ruotolo Brandon T.
Published: July 2014

The three‐dimensional structures adopted by proteins are predicated by their many biological functions. Mass spectrometry has played a rapidly expanding role in protein structure discovery, enabling the generation of models for both proteins and their higher‐order assemblies. While important coursed‐grained insights have been generated, relatively few examples exist where mass spectrometry has been successfully applied to the characterization of protein tertiary structure. Here, we demonstrate that gas‐phase unfolding can be used to determine the number of autonomously folded domains within monomeric proteins. Our ion mobility‐mass spectrometry data highlight a strong, positive correlation between the number of protein unfolding transitions observed in the gas phase and the number of known domains within a group of sixteen proteins ranging from 8–78 kDa. This correlation and its potential uses for structural biology is discussed.
Highly Ordered Mesoporous Tungsten Oxides with a Large Pore Size and Crystalline Framework for H2S Sensing
Authors: Li Yuhui , Luo Wei , Qin Nan , Dong Junping , Wei Jing , Li Wei , Feng Shanshan , Chen Junchen , Xu Jiaqiang , Elzatahry Ahmed A. , Es‐Saheb Mahir H. , Deng Yonghui , Zhao Dongyuan
Published: July 2014

An ordered mesoporous WO3 material with a highly crystalline framework was synthesized by using amphiphilic poly(ethylene oxide)‐b‐polystyrene (PEO‐b‐PS) diblock copolymers as a structure‐directing agent through a solvent‐evaporation‐induced self‐assembly method combined with a simple template‐carbonization strategy. The obtained mesoporous WO3 materials have a large uniform mesopore size (ca. 10.9 nm) and a high surface area (ca. 121 m2 g−1). The mesoporous WO3‐based H2S gas sensor shows an excellent performance for H2S sensing at low concentration (0.25 ppm) with fast response (2 s) and recovery (38 s). The high mesoporosity and continuous crystalline framework are responsible for the excellent performance in H2S sensing.
“Raft” Formation by Two‐Dimensional Self‐Assembly of Block Copolymer Rod Micelles in Aqueous Solution
Authors: Rizis Georgios , van de Ven Theo G. M. , Eisenberg Adi
Published: July 2014

Block copolymers can form a broad range of self‐assembled aggregates. In solution, planar assemblies usually form closed structures such as vesicles; thus, free‐standing sheet formation can be challenging. While most polymer single crystals are planar, their growth usually occurs by uptake of individual chains. Here we report a novel lamella formation mechanism: core‐crystalline spherical micelles link up to form rods in solution, which then associate to yield planar arrays. For the system of poly(ethylene oxide)‐block‐polycaprolactone in water, co‐assembly with homopolycaprolactone can induce a series of morphological changes that yield either rods or lamellae. The underlying lamella formation mechanism was elucidated by electron microscopy, while light scattering was used to probe the kinetics. The hierarchical growth of lamellae from one‐dimensional rod subunits, which had been formed from spherical assemblies, is novel and controllable in terms of product size and aspect ratio.
Copper‐Catalyzed Borylative Allyl–Allyl Coupling Reaction
Authors: Semba Kazuhiko , Bessho Naoto , Fujihara Tetsuaki , Terao Jun , Tsuji Yasushi
Published: July 2014

Borylative allyl–allyl coupling using allenes, bis(pinacolato)diboron, and allyl phosphates has been developed in the presence of a copper catalyst bearing an N‐heterocyclic carbene ligand. The reaction affords boryl‐substituted 1,5‐diene derivatives in good to high yields with high regioselectivity and Z selectivity.
Femtosecond Excitonic Relaxation Dynamics of Perovskite on Mesoporous Films of Al2O3 and NiO Nanoparticles
Authors: Hsu Hung‐Yu , Wang Chi‐Yung , Fathi Amir , Shiu Jia‐Wei , Chung Chih‐Chun , Shen Po‐Shen , Guo Tzung‐Fang , Chen Peter , Lee Yuan‐Pern , Diau Eric Wei‐Guang
Published: July 2014

The excitonic relaxation dynamics of perovskite adsorbed on mesoporous thin films of Al2O3 and NiO upon excitation at 450 nm were investigated with femtosecond optical gating of photoluminescence (PL) via up‐conversion. The temporal profiles of emission observed in spectral region 670–810 nm were described satisfactorily with a composite consecutive kinetic model and three transient components representing one hot and two cold excitonic relaxations. All observed relaxation dynamics depend on the emission wavelength, showing a systematic time–amplitude correlation for all three components. When the NiO film was employed, we observed an extent of relaxation proceeding through the non‐emissive surface state larger than through the direct electronic relaxation channel, which quenches the PL intensity more effectively than on the Al2O3 film. We conclude that perovskite is an effective hole carrier in a p‐type electrode for NiO‐based perovskite solar cells showing great performance.
1,3‐Dehydro‐o‐Carborane: Generation and Reaction with Arenes
Authors: Zhao Da , Zhang Jiji , Xie Zuowei
Published: July 2014

Like the importance of benzyne, witnessed in modern arene chemistry for decades, 1,2‐dehydro‐o‐carborane (o‐carboryne), a three‐dimensional relative of benzyne, has been used as a synthon for generating a wide range of cage, carbon‐functionalized carboranes over the past 20 years. However, the selective B functionalization of the cage still represents a challenging task. Disclosed herein is the first example of 1,3‐dehydro‐o‐carborane featuring a cage CB bond having multiple bonding characters, and is successfully generated by treatment of 3‐diazonium‐o‐carborane tetrafluoroborate with non‐nucleophilic bases. This presents a new methodology for simultaneous functionalization of both cage carbon and boron vertices.
A Square‐Planar Tetracoordinate Oxygen‐Containing Ti4O17 Cluster Stabilized by Two 1,1′‐Ferrocenedicarboxylato Ligands
Authors: Liu Zhichang , Lei Juying , Frasconi Marco , Li Xiaohu , Cao Dennis , Zhu Zhixue , Schneebeli Severin T. , Schatz George C. , Stoddart J. Fraser
Published: July 2014

By introducing steric constraints into molecular compounds, it is possible to achieve atypical coordination geometries for the elements. Herein, we demonstrate that a titanium‐oxo cluster [{Ti4(μ4‐O)(μ2‐O)2}(OPri)6(fdc)2], which possesses a unique edge‐sharing Ti4O17 octahedron tetramer core, is stabilized by the constraints produced by two orthogonal 1,1′‐ferrocenedicarboxylato (fdc) ligands. As a result, a square‐planar tetracoordinate oxygen (ptO) can be generated. The bonding pattern of this unusual anti‐van’t Hoff/Le Bel oxygen, which has been probed by theoretical calculations, can be described by two horizontally σ‐bonded 2px and 2py orbitals along with one perpendicular nonbonded 2pz orbital. While the two ferrocene units are separated spatially by the ptO with an Fe⋅⋅⋅Fe separation of 10.4 Å, electronic communication between them still takes place as revealed by the cluster’s two distinct one‐electron electrochemical oxidation processes.
A Borinic Acid Polymer with Fluoride Ion‐ and Thermo‐responsive Properties that are Tunable over a Wide Temperature Range
Authors: Wan Wen‐Ming , Cheng Fei , Jäkle Frieder
Published: July 2014

A new type of smart borinic acid polymer with luminescence and multiple stimuli‐responsive properties is reported. In DMSO with small amounts of water, the homopolymer PBA shows a tunable upper critical solution temperature (UCST). As the amount of water increases from 0 to 2.5 % (v/v), the UCST rises linearly from 20 °C to 100 °C (boiling point of water). Thus, the thermal responsive behavior can be tuned over a wide temperature range. Furthermore, polymer solutions in DMSO show a reversible response to fluoride ions, which can be correlated to the presence of the Lewis acidic borinic acid groups. Upon addition of fluoride, the polymer becomes soluble because the functional R2BOH groups are converted into ionic [R2BF2]− groups, but turns insoluble again upon addition of H2O, which reverses this process.
Observation of Paramagnetic Raman Optical Activity of Nitrogen Dioxide
Authors: Šebestík Jaroslav , Bouř Petr
Published: July 2014

Raman optical activity (ROA) detects the intensity difference between right and left circularly polarized scattered light, and thus brings about enhanced information about the molecules under investigation. The difference is quite small and the technique is mostly constrained to the condensed phase. For NO2 in the presence of a static magnetic field, however, the ROA signal with high ROA/Raman intensity ratio was observed. The signal is so strong owing to molecular paramagnetism and a pre‐resonance signal enhancement. The spectral shape was explained on the basis of the Fermi golden rule and rotational wave functions expanded to a spherical top basis. The results indicate that the technique can be immediately used to obtain information about molecular properties, such as polarizability components. It also has a potential to detect other paramagnetic gases and discriminate among them.
A New Reactivity Mode for the Diazo Group: Diastereoselective 1,3‐Aminoalkylation Reaction of β‐Amino‐α‐Diazoesters To Give Triazolines
Authors: Kuznetsov Alexey , Gulevich Anton V. , Wink Donald J. , Gevorgyan Vladimir
Published: July 2014

A novel mode of reactivity for the diazo group, the 1,3‐addition of a nucleophile and an electrophile to the diazo group, has been realized in the intramolecular aminoalkylation of β‐amino‐α‐diazoesters to form tetrasubstituted 1,2,3‐triazolines. The reaction exhibited a broad scope, good functional group tolerance, and excellent diastereoselectivity. In addition, a new Au‐catalyzed intramolecular transannulation reaction of the obtained propargyl triazolines to give pyrroles has been discovered.
Chain‐Terminating and Clickable NAD+ Analogues for Labeling the Target Proteins of ADP‐Ribosyltransferases
Authors: Wang Yan , Rösner Daniel , Grzywa Magdalena , Marx Andreas
Published: July 2014

ADP‐ribosyltransferases (ARTs) use NAD+ as a substrate and play important roles in numerous biological processes, such as the DNA damage response and cell cycle regulation, by transferring multiple ADP‐ribose units onto target proteins to form poly(ADP‐ribose) (PAR) chains of variable sizes. Efforts to identify direct targets of PARylation, as well as the specific ADP‐ribose acceptor sites, must all tackle the complexity of PAR. Herein, we report new NAD+ analogues that are efficiently processed by wild‐type ARTs and lead to chain termination owing to a lack of the required hydroxy group, thereby significantly reducing the complexity of the protein modification. Due to the presence of an alkyne group, these NAD+ analogues allow subsequent manipulations by click chemistry for labeling with dyes or affinity markers. This study provides insight into the substrate scope of ARTs and might pave the way for the further developments of chemical tools for investigating PAR metabolism.
BH, CH, and BC Bond Activation: The Role of Two Adjacent Agostic Interactions
Authors: Cassen Audrey , Gloaguen Yann , Vendier Laure , Duhayon Carine , Poblador‐Bahamonde Amalia , Raynaud Christophe , Clot Eric , Alcaraz Gilles , Sabo‐Etienne Sylviane
Published: July 2014

Tuning the nature of the linker in a L∼BHR phosphinoborane compound led to the isolation of a ruthenium complex stabilized by two adjacent, δ‐CH and ε‐Bsp2H, agostic interactions. Such a unique coordination mode stabilizes a 14‐electron “RuH2P2” fragment through connected σ‐bonds of different polarity, and affords selective BH, CH, and BC bond activation as illustrated by reactivity studies with H2 and boranes.
Effects of wide‐range γ‐irradiation doses on the structures and properties of 4,4′‐dicyclohexyl methane diisocyanate based poly(carbonate urethane)s
Authors: Zhang Chen , Jiang Xiujuan , Zhao Zhiyang , Mao Lixin , Zhang Liqun , Coates Phil
Published: July 2014

For medical applications, 4,4′‐dicyclohexyl methane diisocyanate (HMDI)‐based poly(carbonate urethane)s were synthesized from HMDI and 1,4‐butanediol as hard segments and poly(carbonate diol) (number‐average molecular weight = 2000 g/mol) as soft segments. The effects of wide‐range γ irradiation on the samples were examined through a series of analytical techniques. Scanning electron microscopy revealed that γ irradiation etched and roughened the surfaces of the irradiated samples. The gel content and crosslinking density measurements confirmed that crosslinking occurred along with degradation at all of the investigated irradiation doses and the degree of both crosslinking and degradation increased with increasing irradiation dose. Fourier transform infrared spectroscopy demonstrated that chain scission in the γ‐irradiated samples occurred at the carbonate and urethane bonds. The decreasing molecular weight and tensile strength indicated that the degradation increased with the γ‐irradiation dose. Differential scanning calorimetry and dynamic mechanical thermal analysis indicated that γ irradiation had no significant effect on the phase‐separation structures. There was a slight reduction in the contact angle. An evaluation of the cytotoxicity demonstrated the nontoxicity of the nonirradiated and irradiated polyurethanes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41049.
Comparative analysis of different properties of polyhydroxyalkanoates isolated from two different bacterial strains: Alkaliphilus oremlandii OhILAs and recombinant Escherichia coli XL1B
Authors: Pramanik Nilkamal , Mukherjee Khushi , Nandy Arpita , Mukherjee Shritama , Kundu Patit Paban
Published: July 2014

We synthesized poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) [P(3‐HB‐co‐3‐HV)] copolymer having different contents of 3‐hydroxyvalerate (3‐HV) units (16.04, 16.3, 24.95, 25.62, and 16.52 mol % 3‐HV) with different yields of polyhydroxyalkanoates (PHAs) by feeding with different cooking oils and with Alkaliphilus oremlandii OhILAs strain. The PHA production efficiency of the Alkaiphilus strain was compared with that of the control strain, Bacillus cereus. The synthesis of each PHA biopolymer was performed with different toxic spent oils as the sole carbon source in an oil‐in‐water‐based microemulsion medium. We observed that the productivity of the poly(3‐hydroxybutyrate) [P(3‐HB)] copolymer from the Alkaliphilus strain was higher than those of the PHAs isolated from B. cereus and the Escherichia coli XL1B strain. The synthesized PHA copolymers were characterized by 1H‐NMR and Fourier transform infrared (FTIR) spectroscopy. In the 1H‐NMR spectra, a doublet resonance peak at 1.253 ppm of the/ methyl protons of the 3‐hydroxybutyrate (3‐HB) side group and one at 0.894 ppm due to the methyl protons of the 3‐HV side group indicated the presence of 3‐HB and 3‐HV units in the copolymer. The chemical shift values at 1.25 and 2.2 ppm, due to the resonance absorption peaks of the methyl protons and methylene protons, confirmed the synthesis of the P(3‐HB) homopolymer. From the FTIR spectra, a strong CO stretching frequency in the range of 1745–1727 cm−1, together with strong CO stretching bands near 1200 cm−1 and a strong band near 3400 cm−1, confirmed the synthesis of P(3‐HB‐co‐3‐HV) and P(3‐HB). Thus, waste cooking oil as a substrate provided an alternate route for the formation of P(3‐HB‐co‐3‐HV) and P(3‐HB) by Alkaliphilus and E. coli strains, respectively. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41080.
Physical aging of partially crosslinked RTM6 epoxy resin
Authors: Moosburger‐Will Judith , Greisel Michael , Horn Siegfried
Published: July 2014

The aging behavior of partially and completely crosslinked RTM6 epoxy resin samples in the glassy state is investigated by thermophysical and mechanical analyses. Curing degree, glass transition temperature, density, and micromechanical modulus are investigated as function of aging period, initial curing degree or depth below the sample surface. A clear increase of density and modulus with aging period as well as an enhanced surface stiffness is detected for all curing degrees. Also, the aging period necessary to achieve the steady state modulus is independent from the curing degree. In contrast, the degree of physical aging induced modulus changes shows a significant dependence on the curing degree. A discontinuity is detected in the so‐called transition region, which is related to the transition from rubber to glassy state during crosslinking. This emphasizes the importance of curing history for physical aging processes and the high potential of partial curing for the development of new processing routes, in particular for production of samples with low sensitivity to physical aging. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41121.
Synthesis of a novel curing agent containing organophosphorus and its application in flame‐retarded epoxy resins
Authors: Xu Miaojun , Zhao Wei , Li Bin
Published: July 2014

A novel amine‐terminated and organophosphorus‐containing compound m‐aminophenylene phenyl phosphine oxide oligomer (APPPOO) was synthesized and used as curing and flame‐retarding agent for epoxy resins. Its chemical structure was characterized by Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (1H NMR), 13C nuclear magnetic resonance, and 31P nuclear magnetic resonance. The flame‐retardant properties, combusting performances, and thermal degradation behaviors of the cured epoxy resins were investigated by limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter test, and thermogravimetric analysis. The EPO/APPPOO thermosets passed V‐1 rating with the thickness of 3.0 mm and the LOI value reached 34.8%. The thermosets could pass V‐2 rating when the thickness of the samples was 1.6 mm. The cone calorimeter test demonstrated that the parameters of EPO/APPPOO thermosets including heat release rate and total heat release significantly decreased compared with EPO/PDA thermosets. Scanning electron microscopy revealed that the incorporation of APPPOO into epoxy resins obviously accelerated the formation of the compact and stronger char layer to improve flame‐retardant properties of the cured epoxy resins during combustion. The mechanical properties and water resistance of the cured epoxy resins were also measured. After the water‐resistance test, EPO/APPPOO thermosets still remained excellent flame retardant and the water uptake was only 0.4%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41159.
The shark fishery in the United Arab Emirates: an interview based approach to assess the status of sharks
Authors: Jabado Rima W. , Al Ghais Saif M. , Hamza Waleed , Henderson Aaron C.
Published: July 2014

Anecdotal evidence suggests that sharks are being targeted in the United Arab Emirates artisanal fishery. However, little information is available on this fishery and baseline information is essential for understanding its impact on shark populations in the Arabian/Persian Gulf, and for managing sharks in this region.

The aim of this study was to investigate the artisanal shark fishery and gain an insight into the social, motivational and economic drivers behind it. Fishery characteristics were examined and the effect of fishing on local shark stocks assessed by interviewing Emirati fishermen across the country (n = 126).

Sharks were found to be increasingly targeted owing to their high value in the global fin trade industry. The majority of fishermen (80%) confirmed that changes in species composition, abundance and sizes of sharks have been continuing for more than two decades, mainly because of overfishing, raising concerns about the sustainability of this fishery.

Results suggest that sharks are likely to be overexploited and that management measures will need to take into account the precautionary principle. There is an urgent need to formulate long‐term and effective conservation and management plans to prevent further declines in a number of species.

Additional efforts should be directed to quantify the ecological implications of the observed changes and determine if these are aggravated by the life‐history traits of the fished species. Such implications should be considered when assessing the sustainability of local fisheries.

The data gathered can now serve as a reference to managers, fisheries scientists and other stakeholders to prioritize future research as well as lay foundations for the development and implementation of national management plans for the protection and conservation of sharks.

Copyright © 2014 John Wiley & Sons, Ltd.
Novel Quinazolin‐4(3H)‐one/Schiff Base Hybrids as Antiproliferative and Phosphodiesterase 4 Inhibitors: Design, Synthesis, and Docking Studies
Authors: Abdel‐Rahman Hamdy M. , Abdel‐Aziz Mohamed , Canzoneri Joshua C. , Gary Bernard D. , Piazza Gary A.
Published: July 2014

A novel series of quinazolin‐4(3H)‐one/Schiff base hybrids was rationally designed and synthesized. The prepared compounds were evaluated for in vitro activity to inhibit phosphodiesterase 4 (PDE4), where several of them showed good‐to‐moderate activity compared to rolipram. Compound 7 showed potent PDE4 inhibition in this series, with an IC50 of 1.60 µM. Compounds that showed PDE4 inhibition were further assessed for antiproliferative activity using different human tumor cell lines. Compound 10 exhibited significant antiproliferative activity with IC50 values of 140, 79, and 320 nM in breast, lung, and colon tumor cells, respectively. Docking of compound 7 in the active site of PDE4B illustrates its possible binding mode and provides insight for further optimizations of this novel scaffold for inhibiting PDE4.
1,4‐Dihydropyrrolo[3,2‐b]pyrrole and Its π‐Expanded Analogues
Authors: Janiga Anita , Gryko Daniel T.
Published: July 2014

Various approaches to the synthesis of 1,4‐dihydropyrrolo[3,2‐b]pyrroles are summarized. Many two‐ and three‐step reaction sequences have been developed, and have allowed access to a broad variety of structures, including not only the parent 1,4‐dihydropyrrolo[3,2‐b]pyrroles, but also their π‐expanded analogues. The newest approaches are critically compared with older strategies. The reactivity of these compounds is also reviewed, with special emphasis on electrophilic aromatic substitution. The synthesis of indolo[3,2‐b]indole derivatives has been the subject of intense investigation. Overall, a few interesting and ingenious approaches toward these ladder‐type heteroacenes have been proposed, reaching total yields in the region of 30 %. Finally, the optical, electrochemical, and other physicochemical properties are presented in the broader perspective of heteropentalenes. The parent 1,4‐dihydro‐pyrrolo[3,2‐b]pyrroles constitute the most electron‐rich, simple, aromatic heterocycles, and their simple derivatives and π‐expanded analogues possess strong violet, blue, or green fluorescence both in solution and in the solid state.
Regioselective C3 Alkenylation of 4 H‐pyrido[1,2‐a]pyrimidin‐4‐ones via Palladium‐Catalyzed CH Activation
Authors: Liu Wenjie , Wang Shaohua , Zhang Qi , Yu Jingwen , Li Jiahe , Xie Zhiwei , Cao Hua
Published: July 2014

A general and efficient palladium‐catalyzed direct C3 alkenylation of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones using AgOAc/O2 as the oxidant has been developed. A variety of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones were successfully coupled with acrylate esters, styrenes, methylvinylketone, and acrylamide in moderate to excellent yields. The reaction exhibited complete regio‐ and stereoselectivity. This transformation provides an attractive new approach to functionalize 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones.
Mitochondrial one‐carbon metabolism and neural tube defects
Authors: Momb Jessica , Appling Dean R.
Published: July 2014

Background: Neural tube defects (NTDs) are one of the most common birth defects in humans. Maternal intake of folic acid was linked to prevention of NTDs in the 1970s. This realization led to the establishment of mandatory and/or voluntary food folic acid fortification programs in many countries that have reduced the incidence of NTDs by up to 70% in humans. Despite 40 years of intensive research, the biochemical mechanisms underlying the protective effects of folic acid remain unknown. Results: Recent research reveals a role for mitochondrial folate‐dependent one‐carbon metabolism in neural tube closure. Conclusion: In this article, we review the evidence linking NTDs to aberrant mitochondrial one‐carbon metabolism in humans and mouse models. The potential of formate, a product of mitochondrial one‐carbon metabolism, to prevent NTDs is also discussed. Birth Defects Research (Part A) 100:576–583, 2014. © 2014 Wiley Periodicals, Inc.
Prüfung, Überwachung und Wartung von Litzenbündelseilen
Authors: Gläser Christian , Brand Werner , Kuhn Eric , Mack Thomas
Published: July 2014

Litzenbündelseile für Schrägseilbrücken stellen eine wartungsfreundliche Bauweise dar, welche bei der Elbebrücke Schönebeck beispielhaft eingesetzt wurde. Nach abgeschlossenem Seileinbau wurden verschiedene Prüfungen durchgeführt, die zum Teil durch die Ausschreibung als Abnahmeprüfung gefordert waren oder zum anderen Teil als Referenzmessungen für zukünftige Bauwerksprüfungen dienen.

Zur Seilkraftbestimmung kamen Schwingungsmessungen zur Anwendung, die unter besonderer Berücksichtigung der Biegesteifigkeit ausgewertet wurden. Die Schwingungsmessungen wurden auch hinsichtlich des Dämpfungsverhaltens der Seile ausgewertet. Für eine einfache Kraftmessung während üblicher Hauptprüfungen wurden auch elektromagnetische Kraftmesssensoren eingebaut.

Zur Detektion möglicher Drahtbrüche außerhalb der Verankerungen wurde ein eigens für Litzenbündelseile konzipiertes Prüfgerät eingesetzt, das durch um den Seilumfang angeordnete Magnetisierungsspulen auch bei den relativ kleinen Hüllrohrfüllungsgraden eine volle Magnetisierung und damit eine Ortung von Spannstahlbrüchen auch im Seilinnern zulässt.

Testing, Monitoring and Maintenance of Parallel Strand Cables – Example: Elbe Bridge Schoenebeck

Parallel strand cables for cable stayed bridges are easy to monitor which is verified on the Elbe Bridge Schoenebeck. After cable installation, several tests were carried out that were partly required as a verification test by the bidding procedure and partly used as reference measurements for future structure inspections.

Vibration measurements that were evaluated while specifically taking into account bending stiffness were used to determine stay cable forces. The vibration measurements were also evaluated with regard to the damping behavior of the stays. Elastomagnetic force sensors were also installed to permit easy force measurement during detailed inspection.

A testing device that had been especially designed for parallel strand cables was used for detecting possible wire fractures outside of the anchorages. Thanks to magnetizing coils that are placed around the stay cable circumference, this testing device permits full magnetization even for relatively small duct filling levels and thus also ensures a detection of prestressing steel fractures within the cable.
Zerstörungsfreie Prüfverfahren in der Praxis – Möglichkeiten und Grenzen
Authors: Bastert Heinrich , Taffe Alexander , Willmes Michael
Published: July 2014

Die zerstörungsfreien Prüfverfahren finden im Bauwesen (ZfPBau) zunehmend Anwendung und gewinnen dort an Bedeutung. Beim Bauen im Bestand sind ZfPBau‐Verfahren Werkzeuge zur Zustandsanalyse der vorhandenen Bausubstanz und ermöglichen zudem substanzschonende Probenahmen, schadensfreie Kernbohrungen oder gezielte Bauteilöffnungen. Sie unterstützen die Planung und Ausführung von Instandsetzungen und führen beim Neubau zum Nachweis der Ausführungsqualität. Bei Bauherren, Planern und Bauausführenden ist daher ein zunehmender Informationsbedarf hinsichtlich der richtigen Anwendung von ZfPBau‐Verfahren und Formulierung zuverlässiger Prüfaussagen zu verzeichnen. Die verfügbare Fachliteratur ist jedoch überwiegend verfahrensbezogen strukturiert, häufig mit technisch‐wissenschaftlichen Schwerpunkten.

Practical application of Non‐destructive Testing – Strength and Limitations

Non‐destructive testing (NDT) is commonly used in civil engineering with increasing importance. Several analysis techniques offer new options to analyse the structure of existing buildings as well as testing in a material protecting way. Non‐destructive testing in civil engineering (NDT‐CE) supports the design of structural repair or is used to verify the quality of structural components. Customers, designers, and contractors need information how NDT‐methods are used in the right way. This report gives an overview on non‐destructive testing methods as applied to civil engineering from the point of view of the required inspection or test task. The bases of NDT‐CE methods are briefly described without particular reference to physical principles. The alternatives to and limitations of using non‐destructive testing methods for assessing structures are addressed in the explanation of suitable testing methods for special inspections.
A kinetic‐based approach to understanding heterologous mevalonate pathway function in E. coli
Authors: Weaver Lane J. , Sousa Mirta M. L. , Wang George , Baidoo Edward , Petzold Christopher J. , Keasling Jay D.
Published: July 2014

To aid in debugging efforts to increase yield, titer, and productivity of engineered metabolic pathways, computational models are increasingly needed to predict how changes in experimentally manipulable variables such as enzyme expression map to changes in pathway flux. Here, an ordinary differential equation model is developed for a heterologous mevalonate pathway in E. coli using kinetic parameters culled from literature and enzyme concentrations derived from Selective Reaction Monitoring Mass Spectrometry (SRM‐MS). To identify parameters most important to further experimental investigation, a global sensitivity analysis was performed, which pointed to amorphadiene synthase activity as the main limiting factor for amorphadiene production. Furthermore, the model predicted that in this local enzyme expression regime, the overall pathway flux is insensitive to farnesyl pyrophosphate (FPP)‐mediated inhibition of mevalonate kinase, not supporting a hypothesis that had previously been posited to be limiting amorphadiene production. To test these predictions experimentally, two strains were constructed: (1) a strain containing a homologous mevalonate kinase with weaker feedback inhibition, and (2) a strain with greater amorphadiene synthase expression. The experimental results validate the qualitative model hypotheses and accurately match the predicted productivities for the two strains, particularly when an in vivo‐derived kcat for amorphadiene synthase was substituted for the literature value. These results demonstrate the utility of using kinetic representations of engineered metabolic pathways parameterized with experimentally derived protein concentrations and enzyme kinetic constants to predict productivities and test hypotheses about engineering strategies. Biotechnol. Bioeng. 2015;112: 111–119. © 2014 Wiley Periodicals, Inc.