bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved lipid accumulation by morphology engineering of oleaginous fungus Mortierella isabellina
Authors: Gao Difeng , Zeng Jijiao , Yu Xiaochen , Dong Tao , Chen Shulin 
Published: March 2014

ABSTRACTOleaginous fungi capable of accumulating a considerable amount of lipids are promising sources for lipid‐based biofuel production. The specific productivities of filamentous fungi in submerged fermentation are often correlated with morphological forms. However, the relationship between morphological development and lipid accumulation is not known. In this study, distinct morphological forms of oleaginous fungus Mortierella isabellina including pellets of different sizes, free dispersed mycelia, and broken hyphal fragments were developed by additions of different concentrations of magnesium silicate microparticles. Different morphological forms led to different levels of lipid accumulation as well as different spatial patterns of lipid distribution within pellets/mycelial aggregates. Significant higher lipid content (0.75 g lipid/g cell biomass) and lipid yield (0.18 g lipid/g glucose consumed) were achieved in free dispersed mycelia than in pellets. Moreover, extracellular metabolite analysis showed that production of undesirable by‐product malate was repressed in free dispersed mycelium form. Unveiling the desired morphological form of M. isabellina for lipid accumulation provided insights into molecular mechanism of lipid biosynthesis linked with morphological development, as well as design and optimization of bioprocess to produce lipid‐based biofuels. Biotechnol. Bioeng. 2014;111: 1758–1766. © 2014 Wiley Periodicals, Inc.
Tuning single‐cell oil production in Ashbya gossypii by engineering the elongation and desaturation systems
Authors: Ledesma‐Amaro Rodrigo , Santos María‐Angeles , Jiménez Alberto , Revuelta José Luis 
Published: March 2014

ABSTRACTMicrobial oils represent a sustainable alternative to vegetable oils and animal fats as feedstock for both the chemical and biofuel industries. The applications of microbial oils depend on their fatty acid composition, which is defined by the relative amount of each fatty acid, also considering the length and unsaturations of the acyl chain. These two properties are determined by elongases and desaturases. In the present study, we characterized the elongase and desaturase systems in the filamentous fungus Ashbya gossypii, which is able to accumulate high amounts of lipids. Additionally, both the elongation and desaturation systems were engineered in order to broaden the potential applications of A. gossypii oils. Finally, the properties of the strains engineered for biodiesel production were analyzed, with the observation that A. gossypii is a good candidate for the microbial production of renewable biofuels. Biotechnol. Bioeng. 2014;111: 1782–1791. © 2014 Wiley Periodicals, Inc.
Safety and outcome of combined liver and pancreatic resections
Authors: Addeo P , Oussoultzoglou E , Fuchshuber P , Rosso E , Nobili C , Langella S , Jaeck D , Bachellier P 
Published: March 2014

Abstract

Background
In Western countries, combined liver and pancreatic resections (CLPR) are performed rarely because of the perceived high morbidity and mortality rates. This study evaluated the safety and outcomes of CLPR at a tertiary European centre for hepatopancreatobiliary surgery.

Methods
A review of two prospectively maintained databases for pancreatic and liver resections was undertaken to identify patients undergoing CLPR between January 1994 and January 2012. Clinicopathological and surgical outcomes were analysed. Univariable and multivariable analyses for postoperative morbidity were performed.

Results
Fifty consecutive patients with a median age of 58 (range 20–81) years underwent CLPR. Indications for surgery were neuroendocrine carcinoma (16 patients), biliary cancer (15), colonic cancer (5), duodenal cancer (1) and others (13). The type of pancreatic resection included pancreaticoduodenectomy (30), distal pancreatectomy (17), spleen-preserving distal pancreatectomy (2) and total pancreatectomy (1). Twenty-three patients had associated major hepatectomies, 27 underwent minor liver resections and 11 had associated vascular resections. Mortality and morbidity rates were 4 and 46 per cent respectively. Univariable and multivariable analysis showed no differences in postoperative morbidity in relation to extent of liver resection or type of pancreatic resection. Use of preoperative chemotherapy was the only independent risk factor associated with postoperative morbidity (P = 0·021).

Conclusion
CLPR can be performed with fairly low morbidity and mortality rates. Postoperative outcomes were not affected by the extent of liver resection or the type of pancreatic resection. Patients receiving chemotherapy should be evaluated carefully before surgery is considered.
Validation of international consensus guidelines for the resection of branch duct-type intraductal papillary mucinous neoplasms
Authors: Jang J-Y , Park T , Lee S , Kang M J , Lee S Y , Lee K B , Chang Y R , Kim S-W 
Published: March 2014

Abstract

Background
Classifications of intraductal papillary mucinous neoplasm (IPMN) remain ambiguous, especially for the mixed type. Factors predicting malignancy remain unclear. The aim of this study was to evaluate the usefulness of factors predicting malignancy in the new international consensus guidelines for resection of branch duct-type (BD)-IPMN and to compare them with those in the previous version.

Methods
A prospectively collected database of patients with biopsy-proven BD-IPMN was analysed to compare factors between the first and second consensus guidelines, particularly as predictors of malignancy.

Results
Of 350 patients with BD-IPMN, sensitivity (0·724) and balanced accuracy (0·751) of the second guidelines were superior to those (0·639 and 0·730) in the first version at the expense of slightly reduced specificity (0·779 versus 0·822 for the first version) by random forest models. Multiple logistic regression analysis showed that main pancreatic duct dilatation greater than 5 mm (hazard ratio (HR) 4·54, 95 per cent confidence interval 2·45 to 8·41; P &lt; 0·001), mural nodules (HR 6·27, 3·27 to 12·01; P &lt; 0·001) and carbohydrate antigen 19–9 level above 37 units/ml (HR 4·03, 1·83 to 8·90; P = 0·001) were independent predictors of BD-IPMN malignancy.

Conclusion
The new consensus guidelines provide better sensitivity, performance of factors predicting malignancy, and balanced accuracy in the diagnosis of BD-IPMN malignancy. Size alone was limited in predicting malignancy. Variability in clinical significance of the individual factors associated with a risk of malignancy indicates the need for a tailored approach in the management of patients with BD-IPMN.
The impact of the distance from the interventional cardiologist's home to the hospital during off hours
Authors: Lotfi Amir , Alreja Gaurav , Kashef Mohammad Amin , Giugliano Gregory R. , Garb Jane , Schweiger Marc 
Published: March 2014

ObjectivesThe impact of the distance from the interventional cardiologist's home to the hospital and door to balloon time (DTBT)BackgroundThe importance of DTBT is highlighted by its inclusion as one of the core quality measures collected by the center for Medicare and Medicaid services and by the Joint commission on Accreditation of Healthcare organizations. We investigated the effect of time of day on the DTBT in patients having primary percutaneous coronary intervention (pPCI) and the impact of distance of the on call interventional cardiologist from the hospital on the DTBT and major adverse cardiac events (MACE) in patients undergoing pPCI during the off hoursMethodsPatients enrolled in the study presented with STEMI either in the field or to the emergency department (ED) and underwent pPCI from October 2007 to July 2009ResultsSignificant predictors of DTBT included a history of prior MI (P = 0.001), prior percutaneous coronary intervention (P = 0.021), prior coronary artery bypass grafting (P < 0.001), and history of diabetes mellitus (P = 0.004). The strongest predictor of DTBT was on versus off hours. Mean DTB was 18.5 min greater during off hours (72 min) compared to on‐hours (53.5 min). The distance from the cardiologist's home to the hospital was not associated with DTBT on multivariable analysis (P = 0.20)ConclusionWhen pPCI is performed in a highly organized STEMI center with broad staff support and expertise in cardiac care, the increase in the DTBT during off hours was not associated with increase MACE rates. © 2014 Wiley Periodicals, Inc.
Bisepoxide Cross‐Linked Enzyme Aggregates—New Immobilized Biocatalysts for Selective Biotransformations
Authors: Weiser Diána , Varga Andrea , Kovács Klaudia , Nagy Flóra , Szilágyi András , Vértessy Beáta G. , Paizs Csaba , Poppe László 
Published: March 2014

AbstractGlycerol diglycidyl ether (GDE) is a convenient and inexpensive bisepoxide cross‐linker as demonstrated by the preparation of cross‐linked enzyme aggregates (CLEAs) from two enzyme classes. The GDE CLEAs of lipase from Pseudomonas fluorescens (AK), lipase from Burkholderia cepacia (PS), and lipase B from Candida antarctica (CaL B) as well as of phenylalanine ammonia‐lyase (PAL) from Petroselinum crispum demonstrated improved properties as compared with their glutaraldehyde (GA) cross‐linked counterparts. Ultrasonication studies indicated that the GDE CLEAs of lipase PS and PAL were mechanically more stable than the GA CLEAs. In the kinetic resolution of rac‐1‐phenylethanol, the catalytic activity of the GDE–lipase CLEAs (U=69.6, 134.8, and 127.4 U g−1 for AK, CaL B, and PS prepared at 22 °C, respectively) surpassed that of the corresponding GA–lipase CLEAs (U=24.4, 131.0, and 119.2 U g−1 for AK, CaL B, and PS prepared at 22 °C, respectively). The GDE co‐CLEAs from PAL and bovine serum albumin (BSA) could be recycled at least three times if used for the stereoselective ammonia addition in 6 M ammonia to (E)‐3‐(thiophen‐2‐yl)acrylic acid, whereas the recycling of the conventional GA–PAL CLEAs from this medium failed.
Facile Synthesis of Hybrid Core–Shell Nanospheres for the Asymmetric Transfer Hydrogenation of Aromatic Ketones
Authors: Wei Juan , Zhang Xiaomin , Zhang Xiaoming , Zhao Yaopeng , Li Ruixiang , Yang Qihua 
Published: March 2014

AbstractThe polymer–inorganic hybrid core–shell nanospheres with N‐(para‐toluenesulfonyl)‐1,2‐diphenylethylenediamine in the core and the poly(methyl acrylate) (PMA) polymer in the shell were prepared by using a sol–gel process. The surface properties of solid catalysts were modified by controlling PMA and the cetyltrimethylammonium bromide surfactant in the shell. The water contact angle results suggest that the presence of PMA and cetyltrimethylammonium bromide in the shell increases the surface hydrophobicity. In the Rh‐catalyzed transfer hydrogenation of aromatic ketones in aqueous HCOONa, the solid catalyst with higher surface hydrophobicity demonstrates higher activity, which suggests that suitable surface properties increase the reaction rate by increasing the diffusion rates of hydrophobic substrates. Furthermore, this heterogeneous catalyst can be reused conveniently without loss of ee values.
Whole‐Cell Biocatalysis in Deep‐Eutectic‐Solvents/Aqueous Mixtures
Authors: Maugeri Zaira , Domínguez de María Pablo 
Published: March 2014

AbstractWhole‐cell biocatalysis with the use of baker’s yeast is demonstrated in different mixtures of water with deep eutectic solvents (DESs; choline chloride/glycerol, 1:2 mol/mol). Enantioselective ketone reduction is observed for long reaction times (>200 h), which suggests that the whole cells remain stable in these neoteric solvents. By changing the proportion of the DES added, a complete inversion of enantioselectivity is observed, from approximately 95 % enantiomeric excess (ee) (S) in pure water to approximately 95 % ee (R) in the pure DES. Presumably, some (S)‐oxidoreductases present in baker’s yeast are inhibited by DESs.
Correlated Coordination and Redox Activity of a Hemilabile Noninnocent Ligand in Nickel Complexes
Authors: Paretzki Alexa , Bubrin Martina , Fiedler Jan , Záliš Stanislav , Kaim Wolfgang 
Published: March 2014

AbstractThe compound [Ni(QM)2], QM=4,6‐di‐tert‐butyl‐N‐(2‐methylthiomethylphenyl)‐o‐iminobenzoquinone, is a singlet diradical species with approximately planar configuration at the tetracoordinate metal atom and without any NiS bonding interaction. One‐electron oxidation results in additional twofold NiS coordination (dNiS≈2.38 Å) to produce a complex cation of [Ni(QM)2](PF6) with hexacoordinate NiII and two distinctly different mer‐configurated tridentate ligands. The O,O′‐trans arrangement in the neutral precursor is changed to an O,O′‐cis configuration in the cation. The EPR signal of [Ni(QM)2](PF6) has a very large g anisotropy and the magnetic measurements indicate an S=3/2 state. The dication was structurally characterized as [Ni(QM)2](ClO4)2 to exhibit a similar NiN2O2S2 framework as the monocation. However, the two tridentate (O,N,S) ligands are now equivalent according to the formulation [NiII(QM0)2]2+. Cyclic voltammetry reflects the qualitative structure change on the first, but not on the second oxidation of [Ni(QM)2], and spectroelectrochemistry reveals a pronounced dependence of the 800–900 nm absorption on the solvent and counterion. Reduction of the neutral form occurs in an electrochemically reversible step to yield an anion with an intense near‐infrared absorption at 1345 nm (ε=10400 M−1 cm−1) and a conventional g factor splitting for a largely metal‐based spin (S=1/2), suggesting a [(QM.−)NiII(QM2−)]− configuration with a tetracoordinate metal atom with antiferromagnetic NiII–(QM.−) interactions and symmetry‐allowed ligand‐to‐ligand intervalence charge transfer (LLIVCT). Calculations are used to understand the NiS binding activity as induced by remote electron transfer at the iminobenzoquinone redox system.
Exploiting Aromatic Interactions for β‐Peptide Foldamer Helix Stabilization: A Significant Design Element
Authors: Mándity István M. , Monsignori Antonella , Fülöp Lívia , Forró Enikö , Fülöp Ferenc 
Published: March 2014

AbstractTetrameric H10/12 helix stabilization was achieved by the application of aromatic side‐chains in β‐peptide oligomers by intramolecular backbone–side chain CH–π interactions. Because of the enlarged hydrophobic surface of the oligomers, a further aim was the investigation of the self‐assembly in a polar medium for the β‐peptide H10/12 helices. NMR, ECD, and molecular modeling results indicated that the oligomers formed by cis‐[1S,2S]‐ or cis‐[1R,2R]‐1‐amino‐1,2,3,4‐tetrahydronaphthalene‐2‐carboxylic acid (ATENAC) and cis‐[1R,2S]‐ or cis‐[1S,2R]‐2‐aminocyclohex‐3‐enecarboxylic acid (ACHEC) residues promote stable H10/12 helix formation with an alternating backbone configuration even at the tetrameric chain length. These results support the view that aromatic side‐chains can be applied for helical structure stabilization. Importantly, this is the first observation of a stable H10/12 helix with tetrameric chain‐length. The hydrophobically driven self‐assembly was achieved for the helix‐forming oligomers, seen as vesicles in transmission electron microscopy images. The self‐association phenomenon, which supports the helical secondary structure of these oligomers, depends on the hydrophobic surface area, because a higher number of aromatic side‐chains yielded larger vesicles. These results serve as an essential element for the design of helices relating to the H10/12 helix. Moreover, they open up a novel area for bioactive foldamer construction, while the hydrophobic area gained through the aromatic side‐chains may yield important receptor–ligand interaction surfaces, which can provide amplified binding strength.
Nickel(I) Monomers and Dimers with Cyclopentadienyl and Indenyl Ligands
Authors: Wu Jianguo , Nova Ainara , Balcells David , Brudvig Gary W. , Dai Wei , Guard Louise M. , Hazari Nilay , Lin Po‐Heng , Pokhrel Ravi , Takase Michael K. 
Published: March 2014

AbstractThe reaction of (μ‐Cl)2Ni2(NHC)2 (NHC=1,3‐bis(2,6‐diisopropylphenyl)‐1,3‐dihydro‐2H‐imidazol‐2‐ylidene (IPr) or 1,3‐bis(2,6‐diisopropylphenyl)imidazolidin‐2‐ylidene (SIPr)) with either one equivalent of sodium cyclopentadienyl (NaCp) or lithium indenyl (LiInd) results in the formation of diamagnetic NHC supported NiI dimers of the form (μ‐Cp)(μ‐Cl)Ni2(NHC)2 (NHC=IPr (1 a) or SIPr (1 b); Cp=C5H5) or (μ‐Ind)(μ‐Cl)Ni2(NHC)2 (NHC=IPr (2 a) or SIPr (2 b); Ind=C7H9), which contain bridging Cp and indenyl ligands. The corresponding reaction between two equivalents of NaCp or LiInd and (μ‐Cl)2Ni2(NHC)2 (NHC=IPr or SIPr) generates unusual 17 valence electron NiI monomers of the form (η5‐Cp)Ni(NHC) (NHC=IPr (3 a) or SIPr (3 b)) or (η5‐Ind)Ni(NHC) (NHC=IPr (4 a) or SIPr (4 b)), which have nonlinear geometries. A combination of DFT calculations and NBO analysis suggests that the NiI monomers are more strongly stabilized by the Cp ligand than by the indenyl ligand, which is consistent with experimental results. These calculations also show that the monomers have a lone unpaired‐single‐electron in their valence shell, which is the reason for the nonlinear structures. At room temperature the Cp bridged dimer (μ‐Cp)(μ‐Cl)Ni2(NHC)2 undergoes homolytic cleavage of the NiNi bond and is in equilibrium with (η5‐Cp)Ni(NHC) and (μ‐Cl)2Ni2(NHC)2. There is no evidence that this equilibrium occurs for (μ‐Ind)(μ‐Cl)Ni2(NHC)2. DFT calculations suggest that a thermally accessible triplet state facilitates the homolytic dissociation of the Cp bridged dimers, whereas for bridging indenyl species this excited triplet state is significantly higher in energy. In stoichiometric reactions, the NiI monomers (η5‐Cp)Ni(NHC) or (η5‐Ind)Ni(NHC) undergo both oxidative and reductive processes with mild reagents. Furthermore, they are rare examples of active NiI precatalysts for the Suzuki–Miyaura reaction. Complexes 1 a, 2 b, 3 a, 4 a and 4 b have been characterized by X‐ray crystallography.
Efficient Luminescence from Fluorene‐ and Spirobifluorene‐Based Lanthanide Complexes upon Near‐Visible Irradiation
Authors: Bottaro Gregorio , Rizzo Fabio , Cavazzini Marco , Armelao Lidia , Quici Silvio 
Published: March 2014

AbstractWe describe herein the synthesis and photophysical characterization of new lanthanide complexes that consist of a (9,9‐dimethylfluoren‐2‐yl)‐2‐oxoethyl or a (9,9′‐spirobifluoren‐2‐yl)‐2‐oxoethyl unit as the antenna, covalently linked to a 1,4,7,10‐tetraazacyclododecane‐1,4,7‐triacetic acid (DO3A) unit as the Ln3+ (Gd3+, Eu3+, Sm3+, Tb3+, Dy3+) coordination site. We were able to translate the spectroscopic properties of the innovative bipartite ligands into the formation of highly luminescent europium complexes that exhibit efficient emission (ϕse>0.1) upon sensitization in the near‐visible region, that is, with an excitation wavelength above 350 nm. The luminescence of the Eu3+complexes is clearly detectable at concentrations as low as 10 pM. Furthermore, the structural organization of these bipartite ligands makes the complexes highly soluble in aqueous solutions and chemically stable over time.
Diazonium Salts as Grafting Agents and Efficient Radical‐Hydrosilylation Initiators for Freestanding Photoluminescent Silicon Nanocrystals
Authors: Höhlein Ignaz M. D. , Kehrle Julian , Helbich Tobias , Yang Zhenyu , Veinot Jonathan G. C. , Rieger Bernhard 
Published: March 2014

AbstractThe reactivity of diazonium salts towards freestanding, photoluminescent silicon nanocrystals (SiNCs) is reported. It was found that SiNCs can be functionalized with aryl groups by direct reductive grafting of the diazonium salts. Furthermore, diazonium salts are efficient radical initiators for SiNC hydrosilylation. For this purpose, novel electron‐deficient diazonium salts, highly soluble in nonpolar solvents were synthesized. The SiNCs were functionalized with a variety of alkenes and alkynes at room temperature with short reaction times.
Palladium‐Catalyzed Stereoselective Intramolecular Oxidative Amidation of Alkenes in the Synthesis of 1,3‐ and 1,4‐Amino Alcohols and 1,3‐Diamines
Authors: Malkov Andrei V. , Lee Darren S. , Barłóg Maciej , Elsegood Mark R. J. , Kočovský Pavel 
Published: March 2014

AbstractAn efficient and practical Pd‐catalyzed intramolecular oxidative allylic amidation provides facile access to derivatives of 1,3‐ and 1,4‐amino alcohols and 1,3‐diamines. The method operates under mild reaction conditions (RT) with molecular oxygen (1 atm) as the sole reoxidant of Pd. Excellent diastereoselectivities were attained with substrates bearing a secondary stereogenic center
Main‐Chain Organometallic Microporous Polymers Bearing Triphenylene–Tris(N‐Heterocyclic Carbene)–Gold Species: Catalytic Properties
Authors: Gonell Sergio , Poyatos Macarena , Peris Eduardo 
Published: March 2014

AbstractTwo triphenylene‐based tris(N‐heterocyclic carbene)–gold–acetylide main‐chain organometallic microporous polymers (MOMPs) were obtained and fully characterized. Both materials show spherical shapes, and their size is highly dependent on the type of acetylene used in the synthetic protocol. The new solids were tested in the catalytic reduction of nitroarenes with NaBH4 and in the three‐component Strecker reaction for the synthesis of α‐aminonitriles, and showed high activity in both processes. Whereas the activity of the solids in the reduction of nitroarenes may be attributed to the formation of Au nanoparticles due to the use of NaBH4 as reducing agent, the activity in the Strecker reaction may originate from the Lewis acidic activation of the ketone or imine on coordination to Au.
Thiazole‐Based γ‐Building Blocks as Reverse‐Turn Mimetic to Design a Gramicidin S Analogue: Conformational and Biological Evaluation
Authors: Legrand Baptiste , Mathieu Loïc , Lebrun Aurélien , Andriamanarivo Soahary , Lisowski Vincent , Masurier Nicolas , Zirah Séverine , Kang Young Kee , Martinez Jean , Maillard Ludovic T. 
Published: March 2014

AbstractThis paper describes the ability of a new class of heterocyclic γ‐amino acids named ATCs (4‐amino(methyl)‐1,3‐thiazole‐5‐carboxylic acids) to induce turns when included in a tetrapeptide template. Both hybrid Ac‐Val‐(R or S)‐ATC‐Ile‐Ala‐NH2 sequences were synthesized and their conformations were studied by circular dichroism, NMR spectroscopy, MD simulations, and DFT calculations. It was demonstrated that the ATCs induced highly stable C9 pseudocycles in both compounds promoting a twist turn and a reverse turn conformation depending on their absolute configurations. As a proof of concept, a bioactive analogue of gramicidin S was successfully designed using an ATC building block as a turn inducer. The NMR solution structure of the analogue adopted an antiparallel β‐pleated sheet conformation similar to that of the natural compound. The hybrid α,γ‐cyclopeptide exhibited significant reduced haemotoxicity compared to gramicidin S, while maintaining strong antibacterial activity.
Reweighting estimators for the additive hazards model with missing covariates
Authors: Hao Meiling , Song Xinyuan , Sun Liuquan 
Published: March 2014

AbstractMissing covariate data are common in biomedical studies. In this paper, we propose a reweighting method to estimate the regression parameters in the additive hazards regression model when some of the covariates are missing at random. The resulting estimators are shown to be consistent and asymptotically normal. In addition, a lack‐of‐fit test is presented to assess the adequacy of the model with missing covariates. Simulation studies show that the proposed reweighting estimators perform well, and are more efficient than the weighted estimators for the missing covariate effects when the selection probability is small. An application to the mouse leukaemia data is provided.The Canadian Journal of Statistics42: 285–307; 2014 © 2014 Statistical Society of Canada