bluuebunny/crossref_metadata_2025 huggingface dataset:
The Di‐Iron OxygenasePhnZ
Authors: Séguin Jacqueline P , Zechel David L
Published: June 2016

PhnZ is a di‐iron‐dependent monooxygenase from the HD superfamily of metal ion‐dependent phosphohydrolases. These enzymes utilize a conserved histidine‐aspartate motif in the active site for metal ion binding. PhnZ is commonly found in marine bacteria where it works in tandem with the α‐ketoglutarate‐dependent dioxygenase PhnY to extract inorganic phosphate from the organophosphonate natural product 2‐aminoethylphosphonic acid. PhnY hydroxylates 2‐aminoethylphosphonic acid stereospecifically to generate (R)‐2‐amino‐1‐hydroxyethylphosphonic acid, whereupon PhnZ catalyzes the oxidative cleavage of the carbon–phosphorus bond yielding glycine and inorganic phosphate. Analysis of the metal ion dependence of PhnZ through activity assays, ICP‐MS, Mössbauer spectroscopy, and EPR spectroscopy have shown that this enzyme utilizes a mixed‐valence Fe(II)/Fe(III) di‐iron cofactor for catalysis. The X‐ray crystal structures of PhnZ have revealed that one Fe ion (Fe2) is used to bind the substrate in a bidentate manner, while the other Fe ion (Fe1) is likely used to reduce dioxygen. Two conserved active site residues, Y24 and E27, are observed to migrate in and out of the active site in response to substrate binding. Y24 is observed to bind Fe2, occupying the putative dioxygen binding site, but is expelled upon recognition of the substrate amino group by the residue E27. This is proposed to allow dioxygen to bind to Fe1, placing it well within proximity of the substrate bound at Fe2. A mechanism for oxidative carbon–phosphorus bond cleavage by PhnZ has been proposed based on these results. PhnZ not only represents the third known mechanism for enzymatic cleavage of CP‐bonds but also provides a window into the evolution of new functions within an enzyme superfamily.
A Rapid, Low‐Cost, and Scalable Technique for Printing State‐of‐the‐Art Organic Field‐Effect Transistors
Authors: Temiño Inés , Del Pozo Freddy G. , Ajayakumar M. R. , Galindo Sergi , Puigdollers Joaquim , Mas‐Torrent Marta
Published: June 2016

In the last few years exciting advances have been achieved in developing printing techniques for organic semiconductors, and impressive mobility values have been reported for the resulting organic field‐effect transistors (OFETs). However, not all these techniques are scalable and some of them require additional crystallization steps. This study reports on the fabrication of OFETs employing blends of four benchmark organic semiconductors with polystyrene and demonstrates that applying the same formulation and experimental conditions for printing them, highly reproducible and uniform crystalline films exhibiting high OFET performance are successfully achieved. It is noted that the mobility values achieved here are not the highest reported for the studied materials; however, they are state‐of‐the‐art values and could be regarded as exceptional considering the low cost and fast speed of the fabrication process involved here.
Zinc‐Catalyzed Tandem Diels–Alder Reactions of Enynals with Alkenes: Generation and Trapping of Cyclic o‐Quinodimethanes (o‐QDMs)
Authors: Zhang Jiantao , Xiao Yelin , Chen Kai , Wu Wanqing , Jiang Huanfeng , Zhu Shifa
Published: June 2016

A systematic investigation of ZnCl2‐catalyzed reactions of enynals with alkenes has been undertaken. Structurally unique propeller‐like products could be obtained under mild conditions. Cyclic o‐quinodimethanes (o‐QDMs) are generated through [4+2] cycloaddition between enynals and alkenes. Both electron‐poor and electron‐rich dienophiles could be used to trap the active intermediate through [4+2] cycloaddition. But [1,5]‐H shift products could also be observed when electron‐rich alkenes were used as dienophile. DFT calculations were performed to understand the reaction mechanism. A competition between the [4+2] cycloaddition and [1,5]‐H shift was proposed for the transformation of cyclic o‐QDMs. The selectivity could be affected by the properties of the substrates.

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Graphene‐Based Nanocomposites for Energy Storage
Authors: Ji Liwen , Meduri Praveen , Agubra Victor , Xiao Xingcheng , Alcoutlabi Mataz
Published: June 2016

Since the first report of using micromechanical cleavage method to produce graphene sheets in 2004, graphene/graphene‐based nanocomposites have attracted wide attention both for fundamental aspects as well as applications in advanced energy storage and conversion systems. In comparison to other materials, graphene‐based nanostructured materials have unique 2D structure, high electronic mobility, exceptional electronic and thermal conductivities, excellent optical transmittance, good mechanical strength, and ultrahigh surface area. Therefore, they are considered as attractive materials for hydrogen (H2) storage and high‐performance electrochemical energy storage devices, such as supercapacitors, rechargeable lithium (Li)‐ion batteries, Li–sulfur batteries, Li–air batteries, sodium (Na)‐ion batteries, Na–air batteries, zinc (Zn)–air batteries, and vanadium redox flow batteries (VRFB), etc., as they can improve the efficiency, capacity, gravimetric energy/power densities, and cycle life of these energy storage devices. In this article, recent progress reported on the synthesis and fabrication of graphene nanocomposite materials for applications in these aforementioned various energy storage systems is reviewed. Importantly, the prospects and future challenges in both scalable manufacturing and more energy storage‐related applications are discussed.
Macro‐economic multi‐objective input–output model for minimizing CO2 emissions: Application to the U.S. economy
Authors: Pascual‐González Janire , Jiménez‐Esteller Laureano , Guillén‐Gosálbez Gonzalo , Siirola Jeffrey J. , Grossmann Ignacio E.
Published: June 2016

Designing effective environmental policies for mitigating global warming is a very challenging task that requires detailed knowledge of the international channels through which goods are traded. This work presents a decision‐support tool that minimizes the environmental impact at a global macroeconomic scale by performing changes in the economic sectors of an economy. Our tool combines multi‐objective optimization, environmentally extended input–output tables and life cycle assessment within a unified framework. Our results on the U.S. economy to minimize CO2 emissions identify sectors that should be regulated first to reach a given environmental target while maximizing the demand satisfaction. The impact of shale gas on our results is also studied. Our findings show that the application of process systems engineering tools at a macroeconomic level can provide valuable insight for public policy makers into problems of general interest. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3639–3656, 2016
Gain‐of‐function mutations in SMAD4 cause a distinctive repertoire of cardiovascular phenotypes in patients with Myhre syndrome
Authors: Lin Angela E. , Michot Caroline , Cormier‐Daire Valerie , L'Ecuyer Thomas J. , Matherne G. Paul , Barnes Barrett H. , Humberson Jennifer B. , Edmondson Andrew C. , Zackai Elaine , O'Connor Matthew J. , Kaplan Julie D. , Ebeid Makram R. , Krier Joel , Krieg Elizabeth , Ghoshhajra Brian , Lindsay Mark E.
Published: June 2016

Myhre syndrome is a rare, distinctive syndrome due to specific gain‐of‐function mutations in SMAD4. The characteristic phenotype includes short stature, dysmorphic facial features, hearing loss, laryngotracheal anomalies, arthropathy, radiographic defects, intellectual disability, and a more recently appreciated spectrum of cardiovascular defects with a striking fibroproliferative response to surgical intervention. We report four newly described patients with typical features of Myhre syndrome who had (i) a mildly narrow descending aorta and restrictive cardiomyopathy; (ii) recurrent pericardial and pleural effusions; (iii) a large persistent ductus arteriosus with juxtaductal aortic coarctation; and (iv) restrictive pericardial disease requiring pericardiectomy. Additional information is provided about a fifth previously reported patient with fatal pericardial disease. A literature review of the cardiovascular features of Myhre syndrome was performed on 54 total patients, all with a SMAD4 mutation. Seventy percent had a cardiovascular abnormality including congenital heart defects (63%), pericardial disease (17%), restrictive cardiomyopathy (9%), and systemic hypertension (15%). Pericarditis and restrictive cardiomyopathy are associated with high mortality (three patients each among 10 deaths); one patient with restrictive cardiomyopathy also had epicarditis. Cardiomyopathy and pericardial abnormalities distinguish Myhre syndrome from other disorders caused by mutations in the TGF‐β signaling cascade (Marfan, Loeys–Dietz, or Shprintzen–Goldberg syndromes). We hypothesize that the expanded spectrum of cardiovascular abnormalities relates to the ability of the SMAD4 protein to integrate diverse signaling pathways, including canonical TGF‐β, BMP, and Activin signaling. The co‐occurrence of congenital and acquired phenotypes demonstrates that the gene product of SMAD4 is required for both developmental and postnatal cardiovascular homeostasis. © 2016 Wiley Periodicals, Inc.
Continuous‐Flow Synthesis and Derivatization of Aziridines through Palladium‐Catalyzed C(sp3)−H Activation
Authors: Zakrzewski Jacek , Smalley Adam P. , Kabeshov Mikhail A. , Gaunt Matthew J. , Lapkin Alexei A.
Published: June 2016

A continuous‐flow synthesis of aziridines by palladium‐catalyzed C(sp3)−H activation is described. The new flow reaction could be combined with an aziridine‐ring‐opening reaction to give highly functionalized aliphatic amines through a consecutive process. A predictive mechanistic model was developed and used to design the C−H activation flow process and illustrates an approach towards first‐principles design based on novel catalytic reactions.
Direct Synthesis of Phospholyl Lithium from White Phosphorus
Authors: Xu Ling , Chi Yue , Du Shanshan , Zhang Wen‐Xiong , Xi Zhenfeng
Published: June 2016

The selective construction of P−C bonds directly from P4 and nucleophiles is an ideal and step‐economical approach to utilizing elemental P4 for the straightforward synthesis of organophosphorus compounds. In this work, a highly efficient one‐pot reaction between P4 and 1,4‐dilithio‐1,3‐butadienes was realized, which quantitatively affords phospholyl lithium derivatives. DFT calculations indicate that the mechanism is significantly different from that of the well‐known stepwise cleavage of P−P bond in P4 activation. Instead, a cooperative nucleophilic attack of two C
Li bonds on P4, leading to simultaneous cleavage of two P−P bonds, is favorable. This mechanistic information offers a new view on the mechanism of P4 activation, as well as a reasonable explanation for the excellent yields and selectivity. This method could prove to be a useful route to P4 activation and the subsequent production of organophosphorus compounds.
Safe and Selective Nitro Group Reductions Catalyzed by Sustainable and Recyclable Fe/ppm Pd Nanoparticles in Water at Room Temperature
Authors: Feng Jie , Handa Sachin , Gallou Fabrice , Lipshutz Bruce H.
Published: June 2016

As a result of a unique synergy between ligand‐free Fe/ppm Pd nanoparticles and PEG‐containing designer surfactants, a facile and selective reduction of nitro‐containing aromatics and heteroaromatics can be effected in water at room temperature in the presence of NaBH4. This new nanotechnology involves low catalyst loadings, is highly chemoselective, and tolerates a wide variety of functional groups. The process, which includes recycling of the entire aqueous medium, offers a general, environmentally responsible, and notably safe approach to highly valued reductions of nitro‐containing compounds.
Two‐Coordinate Magnesium(I) Dimers Stabilized by Super Bulky Amido Ligands
Authors: Boutland Aaron J. , Dange Deepak , Stasch Andreas , Maron Laurent , Jones Cameron
Published: June 2016

A variety of very bulky amido magnesium iodide complexes, LMgI(solvent)0/1 and [LMg(μ‐I)(solvent)0/1]2 (L=‐N(Ar)(SiR3); Ar=C6H2{C(H)Ph2}2R′‐2,6,4; R=Me, Pri, Ph, or OBut; R′=Pri or Me) have been prepared by three synthetic routes. Structurally characterized examples of these materials include the first unsolvated amido magnesium halide complexes, such as [LMg(μ‐I)]2 (R=Me, R′=Pri). Reductions of several such complexes with KC8 in the absence of coordinating solvents have afforded the first two‐coordinate magnesium(I) dimers, LMg−MgL (R=Me, Pri or Ph; R′=Pri, or Me), in low to good yields. Reductions of two of the precursor complexes in the presence of THF have given the related THF adduct complexes, L(THF)Mg−Mg(THF)L (R=Me; R′=Pri) and LMg−Mg(THF)L (R=Pri; R′=Me) in trace yields. The X‐ray crystal structures of all magnesium(I) complexes were obtained. DFT calculations on the unsolvated examples reveal their Mg−Mg bonds to be covalent and of high s‐character, while Ph⋅⋅⋅Mg bonding interactions in the compounds were found to be weak at best.
Controlling the Stealth Effect of Nanocarriers through Understanding the Protein Corona
Authors: Schöttler Susanne , Landfester Katharina , Mailänder Volker
Published: June 2016

The past decade has seen a significant increase in interest in the use of polymeric nanocarriers in medical applications. In particular, when used as drug vectors in targeted delivery, nanocarriers could overcome many obstacles for drug therapy. Nevertheless, their application is still impeded by the complex composition of the blood proteins covering the particle surface, termed the protein corona. The protein corona complicates any prediction of cell interactions, biodistribution, and toxicity. In particular, the unspecific uptake of nanocarriers is a major obstacle in clinical studies. This Minireview provides an overview of what we currently know about the characteristics of the protein corona of nanocarriers, with a focus on surface functionalization that reduces unspecific uptake (the stealth effect). The ongoing improvement of nanocarriers to allow them to meet all the requirements necessary for successful application, including targeted delivery and stealth, are further discussed.
Functionalized silica nanoparticles for trapping Pb2+ ions via diazo‐azomethine scaffolds
Authors: Narula Priyanka , Mutneja Ruchi , Singh Raghubir , Kaur Varinder
Published: June 2016

Diazo‐azomethine coated silica sorbent for the adsorption of Pb2+ ions has been fabricated. The sorbent was obtained by one‐pot synthesis of silica nanoparticles in the presence of diazo‐azomethine molecules possessing silatranyl side chains for grafting via covalent bond formation. The functionalized silica nanoparticles exhibited characteristic physicochemical properties of diazo‐azomethine scaffolds as determined using Fourier transform infrared spectroscopy, scanning and transmission electron microscopies and thermogravimetric analysis. Various adsorption parameters such as pH, weight of adsorbent, time taken for equilibration and recovery of lead ions were optimized using a batch method. The sorbent showed high adsorption capacity for lead ions of 460.4 mg g−1 at pH = 4. The effect of various competing ions on the adsorption of lead ions was studied and interference was removed by using a masking agent. The sorbent can be regenerated and reused, and is compatible for the adsorption of Pb2+ ions from green leafy vegetables. Copyright © 2016 John Wiley & Sons, Ltd.
Development of lignin carbon fibers: Evaluation of the carbonization process
Authors: Kleinhans Henrik , Salmén Lennart
Published: June 2016

The use of lignin as a renewable resource for the production of less‐expensive carbon fibers has in recent years attracted great interest. In order to develop the strength properties, the stabilization and carbonization processes have to be optimized. For this reason, the process parameters during carbonization have here been studied on stabilized lignin fibers in the temperature interval from 300 to 1300 °C. The effects of temperature, heating rate, and straining of fibers during carbonization on the strength properties of carbon fibers were investigated. The heating rate, in the range from 1 to 40 °C/min, was shown to have no effect on the property development of the fibers. During carbonization with no load applied to the fibers, a shrinkage of 20% was noted. Counteracting the shrinkage by imposing a load on the fibers during the carbonization resulted in fibers with a greater stiffness. The tensile strength was not, however, affected by this loading. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43965.
Novel polyurea polymers with enhanced mechanical properties
Authors: Toader Gabriela , Rusen Edina , Teodorescu Mircea , Diacon Aurel , Stanescu Paul O. , Rotariu Traian , Rotariu Adrian
Published: June 2016

The present work describes the preparation of a set of new polyurea polymers suitable for ballistic protection applications by employing different aromatic diamines derivatives with different flexibility degrees. This modification would allow the synthesis of polymers with both enhanced and controllable mechanical properties through the combination of aliphatic and aromatic molecules. Besides the classical methylene diphenyl diisocyanate and polypropylene glycol bis(2‐aminopropyl ether) (PPG), benzidine, 4,4′‐diaminodiphenylmethane and 3,6‐diamino carbazole were chosen as the third monomer and used in different ratios toward PPG, in order to optimize the polymer properties. The proportions between the polyurea components were selected as such to achieve the total consumption of the monomers. The different types of polyurea obtained have been characterized by Fourier transform infrared spectroscopy, thermal measurements (differential scanning calorimetry and thermogravimetric analysis), tensile tests, and scanning electron microscope. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43967.
Conducting epoxy networks modified with non‐covalently functionalized multi‐walled carbon nanotube with imidazolium‐based ionic liquid
Authors: Lopes Pereira Elaine C. , Soares Bluma G.
Published: June 2016

Multi‐walled carbon nanotube (MWCNT) was non‐covalently functionalized with room‐temperature ionic liquid (IL), 1‐butyl‐3‐methyl‐imidazolium tetrafluoroborate and blended with epoxy pre‐polymer (ER) with the assistance of ultrasonication in the presence of acetone as a diluting medium. The ability of IL in improving the dispersion of MWCNT in epoxy pre‐polymer was evidenced by transmission optical microscopy. The corresponding epoxy/MWCNT networks cured with anhydride displayed an increase of the electrical conductivity of around three orders of magnitude with the addition of IL in a proportion of MWCNT/IL = 1:5 mass ratio. The effect of IL on dynamic mechanical properties and thermal conductivity was also evaluated. The improved thermal and electrical properties was attributed to the better dispersion of MWCNT within the epoxy matrix by IL, evidenced by transmission electron microscopy of the ER/MWCNT networks cured with anhydride. Raman spectroscopy was also used to confirm the interaction between MWCNT and IL. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43976.
Geological subsidence and sinking islands: the case of Manono (Samoa)
Authors: SAND CHRISTOPHE , BOLÉ JACQUES , BARET DAVID , OUETCHO ANDRÉ‐JOHN , PETCHEY FIONA , HOGG ALAN , ASAUA TAUTALA
Published: June 2016

W.R. Dickinson, as part of his wide study of the geological history of the Pacific islands, has linked the unique case of the deeply submerged Lapita site of Mulifanua in western Upolu (Samoa) to the slow subsidence of Upolu island. Recent archaeological research on the neighbouring small island of Manono has yielded new and detailed data on this geological process. A series of new dates has allowed us to define the speed of the subsidence and demonstrate the massive environmental changes to which the local population has had to adapt over the past 2000 years.
Preparation of Ru/Graphene using Glucose as Carbon Source and Hydrogenation of Levulinic Acid to γ‐Valerolactone
Authors: Wu Lingqiao , Song Jinliang , Zhou Baowen , Wu Tianbin , Jiang Tao , Han Buxing
Published: June 2016

The preparation of functional materials and value‐added chemicals using biomass‐derived feedstocks is an interesting topic. Herein, we propose a method to prepare Ru/graphene catalyst using glucose as the carbon source. The catalyst was characterized by scanning and transmission electron microscopies, Raman and X‐ray photoelectron spectroscopies, and X‐ray diffraction. It was found that Ru particles of 2–6 nm were supported uniformly on high‐quality graphene. The performance of the Ru/graphene for hydrogenation of levulinic acid to γ‐valerolactone was studied. The Ru/graphene had much higher activity for the hydrogenation reaction than commercial Ru/C, and was active even at room temperature. The high activity was partially due to the unique structure of graphene, which resulted in an electron‐enriched Ru nanocatalyst. In addition, the Ru/graphene could be reused at least four times without considerable decrease in activity, indicating the excellent stability of the catalyst under our conditions.
Direct Observation of the Collision of Single Pt Nanoparticles onto Single‐Crystalline Gold Nanowire Electrodes
Authors: Shin Changhwan , Bae Hyeonhu , Kang Mijeong , Kim Bongsoo , Kwon Seong Jung
Published: June 2016

We observed the collision of single Pt nanoparticles (NPs) onto an Au nanowire (NW) electrode by using electrocatalytic amplification. Previously, such observations had typically been performed by using a microscale disk‐type ultramicroelectrode (UME). The use of a NW electrode decreased the background noise current and provided a shielding effect, owing to adsorption of the NPs onto the insulating sheath. Therefore, the transient current signal that was caused by the collision of single NPs could be more clearly distinguished from the background current by using a NW electrode instead of a UME. Furthermore, the use of a NW electrode increased the collisional frequency and the magnitude of the transient current signal. The experimental data were analyzed by using a theoretical model and a random walk simulation model.
Ion‐Free and Ion‐Pairing Assemblies of Anion‐Responsive π‐Electronic Systems Possessing Directly Linked Alkyl Chains
Authors: Haketa Yohei , Katayama Daisuke , Fukunaga Shinya , Bando Yuya , Sakurai Tsuneaki , Matsuda Wakana , Seki Shu , Maeda Hiromitsu
Published: June 2016

Alkyl‐substituted pyrrole‐based anion‐responsive π‐electronic systems formed supramolecular gels and liquid crystals through effective π–π stacking and van der Waals interactions. The addition of chloride as a planar cation salt afforded ion‐pairing assemblies as soft materials comprising planar receptor‐Cl− complexes and the cation.
Is advanced maternal age a risk factor for congenital heart disease?
Authors: Best Kate E. , Rankin Judith
Published: June 2016

Background

Studies have reported that advanced maternal age is a risk factor for congenital heart disease (CHD), but none of these have been performed in the United Kingdom. Currently, women in the United Kingdom are not referred for specialist fetal echocardiography based on maternal age alone. The aim of this study is to examine the association between maternal age at delivery and CHD prevalence in the North of England.

Methods

Singleton cases of CHD notified to the Northern Congenital Abnormality Survey and born between January 1, 1998, to December 31, 2013, were included. Cases with chromosomal anomalies were excluded. The relative risk (RR) of CHD according to maternal age at delivery was estimated using Poisson regression.

Results

There were 4024 singleton cases of nonchromosomal CHD, giving a prevalence of 8.1 (95% confidence interval [CI], 7.8–8.3) per 1000 live and stillbirths. There was no association between maternal age at delivery and CHD prevalence (p = 0.97), with no evidence of an increased risk of CHD in mothers aged ≥35 compared to aged 25 to 29 (RR = 0.99; 95% CI, 0.89–1.09). There were no significant associations between maternal age at delivery and severity III CHD (p = 0.84), severity II CHD (p = 0.74), or severity I CHD (p = 0.66), although there was a slight increased risk of severity I CHD in mothers aged ≥35 (RR = 1.27; 95% CI, 0.83–1.95).

Conclusion

We found little evidence that advanced maternal age is a risk factor for CHD. There is no evidence that women in the United Kingdom should be referred for specialist prenatal cardiac screening based on their age. Birth Defects Research (Part A) 106:461–467, 2016. © 2016 Wiley Periodicals, Inc.
Ist die Schnecke, was sie isst?
Authors: Tetsch Larissa
Published: June 2016

Manche Meeresnacktschnecken betreiben mit aus Algen aufgenommenen Chloroplasten Photosynthese und können deshalb vollständig auf weitere Nahrung verzichten. Die Stabilität der “gestohlenen” Chloroplasten wurde mit Gentransfervorgängen vom Algenkerngenom ins Schneckenkerngenom erklärt. Diese Theorie ist inzwischen widerlegt, und es scheint, dass die Chloroplasten ihre Stabilität effektiven Photoschutzmechanismen und einer im Vergleich zu den Chloroplasten der Landpflanzen höheren Codierungsdichte verdanken.
Imposante Fliegenjäger: Am Nistplatz der Kreiselwespen
Authors: Petrischak Hannes
Published: June 2016

Kein von Insekten begeisterter Naturfreund kann sich der Faszination der Kreiselwespe (Bembix rostrata) entziehen, wenn er einmal ihr eindrucksvolles Treiben am Nistplatz erlebt hat. Mit ihrer Größe, ihren Flugkünsten und einer unermüdlichen Brutfürsorge zählt sie zu den besonderen Attraktionen der heimischen Insektenwelt. Unsere einzige nach Bundesartenschutzverordnung geschützte Grabwespe ist allerdings selten, denn ihre Lebensräume – meist offene Sandflächen von Binnendünen – sind vielerorts verschwunden.
Chinarindenbäume (Cinchona)
Authors: Rösemann Ulrich
Published: June 2016

Unter den Tieren hat der Mensch die “Big Five” auf Grund ihrer Größe und Kraft erkoren, doch bei den Pflanzen ist dies ein schlechtes Maß. Betrachtet man ihren Nutzwert für die Menschheit als wichtige Nahrungs‐ oder Medizinalpflanze, spielt die Gattung der Chinarindenbäume in der oberen Liga mit.
Randomized clinical trial of intraoperative endoscopic retrograde cholangiopancreatography versus laparoscopic bile duct exploration in patients with choledocholithiasis
Authors: Poh B R , Ho S P S , Sritharan M , Yeong C C , Swan M P , Devonshire D A , Cashin P A , Croagh D G
Published: June 2016

Background

Various minimally invasive approaches exist for the management of choledocholithiasis at the time of laparoscopic cholecystectomy. The aim of this study was to compare endoscopic retrograde cholangiopancreatography (ERCP) with laparoscopic bile duct exploration (LBDE) and test the hypothesis that intraoperative ERCP is no different to LBDE in terms of rate of bile duct clearance or retained stones.

Methods

Eligible patients with choledocholithiasis undergoing emergency laparoscopic cholecystectomy were randomized to intraoperative ERCP or LBDE in a 1 : 1 ratio. The primary outcomes were rates of bile duct clearance and retained stones. Secondary outcomes were postprocedure complication rate, mortality rate, postoperative length of hospital stay, conversion to open surgery rate, procedural time and total duration of surgery.

Results

Some 104 patients were randomized, and 52 patients in each group were included in an intention-to-treat analysis. Duct clearance rates were 87 per cent for patients who had intraoperative ERCP and 69 per cent for those in the LBDE group (P = 0·057). The rate of retained stones was lower in the ERCP group than in the LBDE group: 15 versus 42 per cent respectively (P = 0·004). Median postoperative length of stay was shorter with ERCP (2 days versus 3 days for LBDE; P = 0·015).

Conclusion

Intraoperative ERCP is more effective than LBDE in terms of minimizing the rate of retained stones in patients with choledocholithiasis undergoing emergency laparoscopic cholecystectomy. Registration number: ACTRN12613000761763 (http://www.anzctr.org.au/).
A novel bioanalytical method based on UHPLC‐HRMS/MS for the quantification of oleuropein in human serum. Application to a pharmacokinetic study
Authors: Lemonakis Nikolaos , Mougios Vassilis , Halabalaki Maria , Skaltsounis Alexios– Leandros , Gikas Evagelos
Published: June 2016

A highly sensitive, rapid and specific ultrahigh‐performance liquid chromatography, coupled to negative electrospray ionization high‐resolution tandem mass spectrometry, method was developed and validated in order to investigate the absorption of dietary oleuropein (OE) in human subjects. Serum samples were collected at predefined time points, after oral administration of an olive leaf extract enriched in OE (204.4 mg OE per capsule) to two subjects. Subsequently, samples were analyzed by the developed method after a simple solid‐phase extraction step. Chromatographic separation was operated with aqueous formic acid, 0.1% (v/v), and acetonitrile following a gradient program at a flow rate of 0.45 mL/min in an RP‐C18 (50 × 2.1 mm, 1.9 μm) column with a total run time of 2.7 min. The method was validated and successfully applied to the determination of OE in human serum, with the pharmacokinetic analysis of the data revealing a biphasic response.
Synergistic association of STX1A and VAMP2 with cryptogenic epilepsy in North Indian population
Authors: Baghel Ruchi , Grover Sandeep , Kaur Harpreet , Jajodia Ajay , Parween Shama , Sinha Juhi , Srivastava Ankit , Srivastava Achal Kumar , Bala Kiran , Chandna Puneet , Kushwaha Suman , Agarwal Rachna , Kukreti Ritushree
Published: June 2016

Introduction

“Common epilepsies”, merely explored for genetics are the most frequent, nonfamilial, sporadic cases in hospitals. Because of their much debated molecular pathology, there is a need to focus on other neuronal pathways including the existing ion channels.

Methods

For this study, a total of 214 epilepsy cases of North Indian ethnicity comprising 59.81% generalized, 40.19% focal seizures, and based on epilepsy types, 17.29% idiopathic, 37.38% cryptogenic, and 45.33% symptomatic were enrolled. Additionally, 170 unrelated healthy individuals were also enrolled. Here, we hypothesize the involvement of epilepsy pathophysiology genes, that is, synaptic vesicle cycle, SVC genes (presynapse), ion channels and their functionally related genes (postsynapse). An interactive analysis was initially performed in SVC genes using multifactor dimensionality reduction (MDR). Further, in order to understand the influence of ion channels and their functionally related genes, their interaction analysis with SVC genes was also performed.

Results

A significant interactive two‐locus model of STX1A_rs4363087|VAMP2_rs2278637 (presynaptic genes) was observed among SVC variants in all epilepsy cases (P1000‐value = 0.054; CVC = 9/10; OR = 2.86, 95%CI = 1.88–4.35). Further, subgroup analysis revealed stronger interaction for the same model in cryptogenic epilepsy patients only (P1000‐value = 0.012; CVC = 10/10; OR = 4.59, 95%CI = 2.57–8.22). However, interactive analysis of presynaptic and postsynaptic genes did not show any significant association.

Conclusions

Significant synergistic interaction of SVC genes revealed the possible functional relatedness of presynapse with pathophysiology of cryptogenic epilepsy. Further, to establish the clinical utility of the results, replication in a large and similar phenotypic group of patients is warranted.
Age‐specific birth rates in women with epilepsy: a population‐based study
Authors: Farmen Anette Huuse , Grundt Jacob Holter , Tomson Torbjörn , Nakken Karl O. , Nakling Jakob , Mowinchel Petter , Øie Merete , Lossius Morten I.
Published: June 2016

Objective

The aim of this study was to investigate birth rates and use of hormonal contraception in different age groups among women with epilepsy (WWE) in comparison to women without epilepsy.

Materials and Methods

Demographic data and medical information on more than 25,000 pregnant women (40,000 births), representing 95% of all pregnancies in Oppland County, Norway, were registered in the Oppland Perinatal Database in the period 1989–2011. Data were analyzed with respect to epilepsy diagnoses, and 176 women with a validated epilepsy diagnosis (303 pregnancies) were identified. Age‐specific birth rates in these women were estimated and compared with age‐specific birth rates in women without epilepsy in the same county.

Results

In WWE over 25 years of age, birth rates were significantly lower than in those of the same age group without epilepsy. In women below 20 years of age, birth rates were similar in those with and without epilepsy. The use of hormonal contraceptives prior to pregnancy was lower among WWE under 25 years than in the corresponding age group without epilepsy.

Conclusions

Health professionals who counsel WWE who are of fertile age should be aware of the strongly reduced birth rates in WWE over 25 years of age, and the lower rates of use of contraceptives among young WWE.
Intestinal mucoadhesive devices for oral delivery of insulin
Authors: Banerjee Amrita , Lee JooHee , Mitragotri Samir
Published: June 2016

Oral delivery of proteins such as insulin has been a long‐lasting challenge owing to gastrointestinal degradation and poor permeability of therapeutic macromolecules across biological membranes. We have developed mucoadhesive intestinal devices for oral delivery of insulin to address this challenge. Here we demonstrate a combination of intestinal devices and a permeation enhancer, dimethyl palmitoyl ammonio propanesulfonate (PPS), for oral delivery of insulin. The devices were delivered from a capsule coated with a pH‐responsive enteric coating. The devices adhere to intestinal mucosa, release their protein load unidirectionally, and prevent enzymatic degradation in the gut. Devices were found to completely release their drug load within 3–4 hr and showed excellent strength of mucoadhesion to porcine intestine. Devices loaded with insulin and PPS significantly decreased blood glucose levels by 30 and 33% in diabetic and nondiabetic rats, respectively. These studies demonstrate that intestinal mucoadhesive devices are a promising oral alternative to insulin injections and therefore should be further explored for the treatment of diabetes.
Designed Proteins as Novel Imaging Reagents in Living Escherichia coli
Authors: Pratt Susan E. , Speltz Elizabeth B. , Mochrie Simon G. J. , Regan Lynne
Published: June 2016

Fluorescence imaging is a powerful tool to study protein function in living cells. Here, we introduce a novel imaging strategy that is fully genetically encodable, does not require the use of exogenous substrates, and adds a minimally disruptive tag to the protein of interest (POI). Our method was based on a set of designed tetratricopeptide repeat affinity proteins (TRAPs) that specifically and reversibly interact with a short, extended peptide tag. We co‐expressed the TRAPs fused to fluorescent proteins (FPs) and the peptide tags fused to the POIs. We illustrated the method using the Escherichia coli protein FtsZ and showed that our system could track distinct FtsZ structures under both low and high expression conditions in live cells. We anticipate that our imaging strategy will be a useful tool for imaging the subcellular localization of many proteins, especially those recalcitrant to imaging by direct tagging with FPs.
Mesoporous High‐Surface‐Area Copper–Tin Mixed‐Oxide Nanorods: Remarkable for Carbon Monoxide Oxidation
Authors: Peng Honggen , Liu Yang , Li Yarong , Zhang Xianhua , Tang Xianglan , Xu Xianglan , Fang Xiuzhong , Liu Wenming , Zhang Ning , Wang Xiang
Published: June 2016

Mesoporous, high‐surface‐area Cu–Sn mixed‐oxide nanorods were fabricated for the first time by nanocasting with the use of mesoporous KIT‐6 silica as the hard template. The Cu–Sn nanorods are significantly more active than 1 % Pd/SnO2 for the oxidation of CO and possesses long‐term durability and potent water resistance; they thus have the potential to replace noble metal catalysts for emission‐control processes.
Synthesis and Catalytic Properties of New Metalloporphyrin‐Based Porous Organic Framework Materials with Single and Accessible Sites
Authors: Meng Shuang , Zou Xiaoqin , Liu Chuanfang , Ma Heping , Zhao Nian , Ren Hao , Jia Mingjun , Liu Jia , Zhu Guangshan
Published: June 2016

It is a big challenge to homogenize heterogeneous catalysts with molecular catalytic performance. With this target in mind, herein, we describe a facile strategy for direct incorporation of single catalytic sites in 3D open porous aromatic frameworks (PAFs). The synthesis of the PAF (denoted as PAF‐76) as well as its derivatives (PAF‐76‐M, M=Fe, Mn, Zn) was achieved by the use of tetrakis(4‐bromophenyl)methane as tetrahedral nodes and tetrakis(4‐bromophenyl)porphyrin as planar nodes. The connection of monomers into an extended network of PAF‐76 was monitored by 13C NMR and FTIR spectroscopies. The prepared PAF‐76s showed 3D porous structures with surface areas of 450–700 m2 g−1, pore volumes of 0.3–0.4 cm3 g−1, and pore sizes around 1.2 nm. The direct incorporation of metalloporphyrin components into the PAF‐76‐M frameworks has allowed the uniform distribution of metal ionic sites throughout the PAF‐76‐M particles. The combined merits of isolated metal sites and suitable pore size make PAF‐76 a good candidate for heterogeneous catalysis. The catalytic performances of the porphyrin/metalloporphyrin‐based active sites in the PAF‐76s were evaluated by aerobic oxidation reactions of styrene, which are usually carried out with homogeneous systems. Metal‐functionalized PAF‐76s (PAF‐76‐M) exhibit enhanced turnover frequencies for styrene conversion (16.9–50.9 mol mol(M)−1 h−1) compared with molecular catalysts (0–35.0 mol mol(M)−1 h−1), and improved selectivity toward phenylacetaldehyde (85.7–99 %) in contrast to their corresponding monomers (0–75.5 %). The robustness of PAF‐76 in terms of high thermal stability, good recyclability, and excellent solvent resistance showed that these PAF‐76 materials hold great promise for developing heterogeneous catalysts.
Tetrathiafulvalene–7,7,8,8‐Tetracyanoquinodimethane and Tetrathiafulvalene–2,3,5,6‐Tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane Organic Charge‐Transfer Complexes: Reusable Catalysts for Electron‐Transfer Reactions
Authors: Hoshyargar Faegheh , O'Mullane Anthony P.
Published: June 2016

The application of organic charge‐transfer complexes such as TTF‐TCNQ (TTF=tetrathiafulvalene, TCNQ=7,7,8,8‐tetracyanoquinodimethane) is well known in the area of organic electronics. However, the applicability of this material and its derivatives has not been explored for catalytic reactions. Herein, we report on the catalytic properties of both TTF‐TCNQ and the significantly less‐known fluorinated analogue TTF‐TCNQF4 (TCNQF4=2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane). The model reaction of ferricyanide ion reduction by thiosulfate ions was chosen, for which it was found that both materials were indeed catalytically active. Significantly, the fluorinated TCNQF4 analogue showed considerably higher catalytic activity than TTF‐TCNQ. In addition, TTF‐TCNQF4 was found to be highly stable under the catalytic conditions and could be recovered and reused without any loss in performance for at least 10 catalytic cycles. This work opens up new avenues for investigating these types of materials for catalytic reactions.
Rational Design of Push–Pull Fluorene Dyes: Synthesis and Structure–Photophysics Relationship
Authors: Shaya Janah , Fontaine‐Vive Fabien , Michel Benoît Y. , Burger Alain
Published: June 2016

Our work surveyed experimental and theoretical investigations to construct highly emissive D–π–A (D=donor, A=acceptor) fluorenes. The synthetic routes were optimised to be concise and gram‐scalable. The molecular design was first rationalised by varying the electron‐withdrawing group from an aldehyde, ketotriazole or succinyl to methylenemalonitrile or benzothiadiazole. The electron‐donating group was next varied from aliphatic or aromatic amines to saturated cyclic amines ranging from aziridine to azepane. Spectroscopic studies correlated with TD‐DFT calculations provided the optimised structures. The selected push–pull dyes exhibited visible absorptions, significant brightness, important solvatofluorochromism, mega‐Stokes shifts (>250 nm) and dramatic shifts in emission to the near‐infrared. The current library includes the comprehensive characterization of 16 prospective dyes for fluorescence applications. Among them, several fluorene derivatives bearing different conjugation anchors were tested for coupling and demonstrated to preserve the photophysical responses once further bound.
Debenzylative Cycloetherification: An Overlooked Key Strategy for Complex Tetrahydrofuran Synthesis
Authors: Tikad Abdellatif , Delbrouck Julien A. , Vincent Stéphane P.
Published: June 2016

Tetrahydrofuran (THF) is a major structural feature found in many synthetic and natural products displaying a variety of biological properties. This review summarizes the main synthetic approaches that have been developed to construct tetrahydrofuran moieties involving debenzylative cycloetherification reactions (DBCE). Interestingly, this reaction is regio‐ and stereoselective without the requirement of a selective protection/deprotection strategy. Many applications of this process have been reported, including carbafuranoside synthesis, regioselective deprotection of the benzyl group positioned γ to an alkene, and total synthesis of natural products. The stereochemical outcome and the mechanism of these interesting transformations are also discussed.
Diiron(III)–μ‐Fluoro Bisporphyrins: Effect of Bridging Ligand on the Metal Spin State
Authors: Sil Debangsu , Kumar Amit , Rath Sankar Prasad
Published: June 2016

A hitherto unknown family of diiron(III)–μ‐fluoro bisporphyrins has been synthesized and structurally characterized. Fluoride abstraction from SbF6− and BF4− resulted in the synthesis of the μ‐fluoro complexes of ethane‐ and ethene‐bridged diiron(III) bisporphyrins. Two such complexes were structurally characterized, which revealed a single fluoro bridge between two iron centers with a remarkably bent Fe‐F‐Fe unit. Although isoelectronic with the μ‐hydroxo complexes, the μ‐fluoro species are quite divergent in terms of the electronic structure and properties. UV/Vis spectroscopy of the μ‐fluoro complex exhibits a large redshift (ca. 18 nm) of the Soret band in comparison to their μ‐hydroxo analog. Combined analysis by single crystal X‐ray structure determination and Mössbauer and 1H NMR spectroscopy revealed the presence of two equivalent iron(III) centers in the μ‐fluoro complexes in both solid and solution phases. In contrast, the iron(III) centers of the μ‐hydroxo complexes are known to be inequivalent. Variable‐temperature magnetic studies show a weak antiferromagnetic interaction between the iron(III) centers of the μ‐fluoro complexes with coupling constants (J) ranging from −33 to −40 cm−1. The experimental results were further supported by DFT calculations.
Post‐Synthetic Polymerization of UiO‐66‐NH2 Nanoparticles and Polyurethane Oligomer toward Stand‐Alone Membranes for Dye Removal and Separation
Authors: Yao Bing‐Jian , Jiang Wei‐Ling , Dong Ying , Liu Zhi‐Xian , Dong Yu‐Bin
Published: June 2016

Metal–organic frameworks (MOFs) are widely used as porous materials in the fields of adsorption and separation. However, their practical application is largely hindered by limitations to their processability. Herein, new UiO‐66‐Urea‐based flexible membranes with MOF loadings of 50 (1), 60 (2), and 70 wt % (3) were designed and prepared by post‐synthetic polymerization of UiO‐66‐NH2 nanoparticles and a polyurethane oligomer under mild conditions. The adsorption behavior of membrane 3 towards four hydrophilic dyes, namely, eosin Y (EY), rhodamine B (RB), malachite green (MG), and methylene blue (MB), in aqueous solution was studied in detail. It exhibits strong adsorption of EY and RB but weak adsorption of MG and MB in aqueous solution. Owing to the selective adsorption of these hydrophilic dyes, membrane 3 can remove EY and RB from aqueous solution and completely separate EY/MB, RB/MG, and RB/MB mixtures in aqueous solution. In addition, the membrane is uniformly textured, easily handled, and can be reused for dye adsorption and separation.
Understanding the Reactivity of Planar Polycyclic Aromatic Hydrocarbons: Towards the Graphene Limit
Authors: García‐Rodeja Yago , Solà Miquel , Fernández Israel
Published: June 2016

The Diels–Alder reactivity of maleic anhydride towards the bay regions of planar polycyclic aromatic hydrocarbons was explored computationally in the DFT framework. The process becomes more and more exothermic and the associated activation barriers become lower and lower when the size of the system increases. This enhanced reactivity follows an exponential behavior that reaches its maximum for systems having 18–20 benzenoid rings in their structures. This peculiar behavior was analyzed in detail by using the activation strain model of reactivity in combination with energy decomposition analysis. The influence of the change in the aromaticity of the polycyclic compound during the process on the respective activation barriers was also studied.
Unexpected Behavior of the Heaviest Halogen Astatine in the Nucleophilic Substitution of Aryliodonium Salts
Authors: Guérard François , Lee Yong‐Sok , Baidoo Kwamena , Gestin Jean‐François , Brechbiel Martin W.
Published: June 2016

Aryliodonium salts have become precursors of choice for the synthesis of 18F‐labeled tracers for nuclear imaging. However, little is known on the reactivity of these compounds with heavy halides, that is, radioiodide and astatide, at the radiotracer scale. In the first comparative study of radiohalogenation of aryliodonium salts with 125I− and 211At−, initial experiments on a model compound highlight the higher reactivity of astatide compared to iodide, which could not be anticipated from the trends previously observed within the halogen series. Kinetic studies indicate a significant difference in activation energy (Ea=23.5 and 17.1 kcal mol−1 with 125I− and 211At−, respectively). Quantum chemical calculations suggest that astatination occurs via the monomeric form of an iodonium complex whereas iodination occurs via a heterodimeric iodonium intermediate. The good to excellent regioselectivity of halogenation and high yields achieved with diversely substituted aryliodonium salts indicate that this class of compounds is a promising alternative to the stannane chemistry currently used for heavy radiohalogen labeling of tracers in nuclear medicine.
Asymmetric Diels–Alder Cycloadditions of Trifluoromethylated Dienophiles Under Trienamine Catalysis
Authors: Yuan Xin , Zhang Shan‐Jun , Du Wei , Chen Ying‐Chun
Published: June 2016

β‐Trifluoromethyl (CF3) enones were proved to act as good dienophiles in asymmetric normal‐electron‐demand Diels–Alder cycloadditions with 2,4‐dienals under trienamine catalysis with a chiral secondary amine. The sequential reductive amination transformations with benzylamine produced cis‐ and trans‐fused chiral trifluoromethylated octahydroisoquinolines in a diastereodivergent manner by using NaBH(OAc)3 and NaBH3CN as the reductants, respectively. Moreover, other types of activated alkenes that bear a CF3 group have also been successfully utilized to construct a diverse range of chiral cyclic frameworks in high stereoselectivity.