bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydroxyl‐modified cationic lipids with a carbamate linkage as gene delivery vehicles
Authors: Qiao Weihong , Zhou Min 
Published: December 2012

AbstractWe have developed four hydroxyl‐modified cationic lipids with a carbamate linkage as delivery of DNA to the cervix cells. A formulation with cationic lipids and 1,2‐Dioleoyl‐sn‐glycero‐3‐phosphoethanolamine at a molar ratio of 1:1, liposomes 1, 2, 3, and 4 were prepared by conventional thin film evaporation and ultrasonic method. Size and Zeta potential of liposome/DNA complexes were measured at different mass ratios, which were 1/1, 2/1, 3/1, 4/1, 6/1, and 8/1, respectively. Delivery of DNA to Hela cells by the liposomes was evaluated by measuring the transfection efficiency of liposome/DNA complexes. The cytotoxicity was investigated at the ratios above. Gene transfection efficiency of liposomes 1, 2, and 3‐DNA complexes was approximately equal to that of Lipo2000–DNA complex, and a lower cytotoxicity compared with Lipo2000. The largest particle‐size occurred at the break point from negative Zeta potential to positive Zeta potential. The biggest size of liposomes 1, 2, 3, and 4 was 1091, 760.5, 1584, and 436.5 nm, respectively. On head group, the length of carbon chain (lipo 2) could enhance transfection efficiency, while the hydroxy increase (lipo 3) could weaken a little. Moreover, the longer lipophilic tail (lipo 4) could evidently cut down the transfection efficiency.Practical applications: The findings of the present study will be useful in biomedical applications for delivery of DNA to the cervix. Cationic lipid gene vectors in the condition of carbamate as connection bond and hydroxyalkyl group as head group may improve the gene therapy transfection efficiency and lower cytotoxicity. Research on high transfection efficiency and low toxic targeting gene vector will provide theoretical guidance and show practical significance for the development of promising gene delivery vehicles.
Heterogeneous Photoinduced Homolytic Aromatic Substitution of Electron‐Rich Arenes with Perfluoroalkyl Groups in Water and Aqueous Media – A Radical‐Ion Reaction
Authors: Barata‐Vallejo Sebastián , Flesia Marina Martín , Lantaño Beatriz , Argüello Juan E. , Peñéñory Alicia B. , Postigo Al 
Published: December 2012

AbstractThe photoinduced electron transfer (PET) substitution reaction of electron‐rich aromatic nuclei with perfluoroalkyl Rf groups was carried out in water or aqueous mixtures to render substitution products resulting from replacement of aromatic H atoms with the Rf moiety in good yields (57–88 %). Some mechanistic aspects are discussed, supporting the notion of a PET reaction leading to a classical radical homolytic aromatic substitution (HAS) followed by an electron transfer (ET) and then a proton transfer (PT) sequence. A radical mechanism superimposed on a redox process is proposed to account for product formation. Evidence for the radical cation species (as an initiation event) generated from electron‐rich arenes in the presence of perfluoroalkyl halides is provided by the UV/Vis transient spectra obtained by Nanosecond Laser Flash Photolysis techniques.
FeCl3‐Mediated Arylation of α‐Hydroxyphosphonates with Unactivated Arenes: Pseudo‐Umpolung in Allylic Phosphonates
Authors: Pallikonda Gangaram , Chakravarty Manab 
Published: December 2012

AbstractAn FeCl3‐mediated regio‐ and stereoselective Friedel–Crafts‐type arylation of α‐hydroxy phosphonates with unactivated arenes has been developed in which the unstable allylphosphonate cations generated are stabilized by extended conjugation. The approach provides a simple, efficient and economic approach to highly demanding stereoselective γ‐aryl‐substituted vinylphosphonates and dialkyl (diarylmethyl)phosphonates with good regioselectivity. These reactions proceed under mild conditions and proceed in the absence of any additional solvent.
New Sulfonated PBIs for PEMFC Application
Authors: Villa D. C. , Angioni S. , Quartarone E. , Righetti P. P. , Mustarelli P. 
Published: December 2012

AbstractPolybenzimidazole (PBI) is one of the polymers of choice to replace Nafion® in polymer fuel cells working at high temperature. In order to improve the membrane electrical properties, several monomer modifications are proposed, including sulfonation which, however, is not generally uniform and complete. By using a proper aryloxy‐based spacer, we reported here a facile synthesis procedure which allowed us to obtain co‐monomers with 100% mono‐ and di‐sulfonation. Preliminary conductivity measurements showed that mono‐sulfonation allowed to increase of one order of magnitude the proton conductivity at high doping level with respect to pyridine‐based PBI, so reaching values around 0.1 S cm–1 at 120 °C and 50% RH. Di‐sulfonation is efficient only at lower doping levels, where it allows a further 2–3 times increase of the conductivity. These materials are promising as membranes for polymer fuel cells.
Permeability and Diffusivity Measurements on Polymer Electrolyte Membranes
Authors: Arena F. , Mitzel J. , Hempelmann R. 
Published: December 2012

AbstractAn essential material property directly influencing the long‐life capacity of hydrogen‐polymer electrolyte membrane fuel cells (H2‐PEMFCs) systems at elevated temperatures (>80 °C) is the permeability of the PEM material toward gases. The membrane permeability with respect to hydrogen and oxygen is responsible for a decrease of fuel cell efficiency and life‐time. Furthermore permeating oxygen is suspected to form membrane degrading O‐radical species. In view of the importance of gas permeability for further PEM R&D activities we present a test bench for the experimental determination of gas diffusivities and permeabilities for such polymeric materials. The advantages of a direct coupling of the permeation measurement cell with a gas chromatograph as analyzer are outlined. Hydrogen and oxygen diffusivities as well as permeabilities of prospective new materials such as cross‐linked SPEEK are determined at different temperatures and are compared to state‐of‐the‐art PFSA material. A significantly lower permeability regarding hydrogen and oxygen was determined for cross‐linked SPEEK materials. In addition the influence of the hydro‐thermal history of PFSA materials, postulated by G. Alberti, on membrane diffusivity was studied.
Does seaweed offer a solution for bioenergy with biological carbon capture and storage?
Authors: Hughes Adam D. , Black Kenny D. , Campbell Iona , Davidson Keith , Kelly Maeve S. , Stanley Michael S. 
Published: December 2012

AbstractThe concept of combining bioenergy with carbon capture and storage (BECCS) has been identified as one mechanism to achieve energy production with a net negative atmospheric carbon emission. Conventional geological carbon capture and storage involves large capital outlay and recurring expense. Therefore there is increased interest in coupling biological carbon capture and sequestration with biomass production. Systems such as low‐input high‐diversity native grasslands and biochar production have been heralded as carbon negative biofuels. Another potential production system for bioenergy with biological carbon capture and storage (BEBCCS) is the large‐scale cultivation of seaweed (macroalgae) for biofuels. Marine biofuels offer considerable advantages over terrestrial first‐generation biofuels in terms of their low land use, fresh water and fertilizer requirements. In addition, they also offer considerable potential in the field of BEBCCS. Macroalgae rapidly accumulate biomass and as part of this process, a significant proportion (estimates range up to 60%) of the carbon they fix photosynthetically is released into the water. A proportion of this released dissolved organic carbon (DOC) is highly labile and enters the bacterial loop and is rapidly remineralized back to CO2. However, a proportion is known to be resistant to biological degradation and enters the refractory DOC pool. The marine DOC pool is the largest organic carbon pool on the planet and the refractory component is known to have a turnover period of 100s‐1000s years. The release of refractory DOC from macroalgae combined with biofuel production offers the potential for large scale carbon negative fuel production. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd
Characterizing CO2 storage reservoirs and shallow overburden for above‐zone monitoring in Texas Gulf Coast EOR fields
Authors: Zahid Khandaker M. , Hosseini Seyyed A. , Nuñez‐López Vanessa , Hovorka Susan D. 
Published: December 2012

AbstractEnhanced oil recovery (EOR) through carbon dioxide (CO2) injection provides an excellent opportunity for commercial sequestration of anthropogenic CO2. A fluvio‐deltaic, deep‐seated salt dome and a strand‐plain, roll‐over anticline from the Gulf Coast region are currently under investigation for the design and implementation of monitoring, verification, and accounting (MVA) plans, in coordination with the commercial surveillance of independent, large‐volume (>1 million ton/year) CO2‐EOR operations. Characterization with wireline logs demonstrates the vertical extent and areal continuity of reservoir sands and geometries of faults that offset the reservoir. To develop the monitoring plan, we focused on several elements: (i) characterization of the zones above the confining unit for above‐zone pressure monitoring, (ii) collection and development of input data for ‘quick‐look’ dynamic modeling of CO2 plume extent and pressure elevation, and (iii) identifying intersections of faults with wellbores in intervals above the regional confining unit for thermal monitoring. Other uncertainties addressed during characterization are the upper extent of faults and the juxtaposition of layers to assess the potential for cross‐fault fluid migration. Successful use of such techniques for MVA, based on uniting elements of existing regulatory monitoring expectations, would lead to the establishment of commercial best practices for effective and rapid characterization of EOR sites in the Gulf Coast region. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd
Synthesis of Enantiomerically Pure Isoxazolidine Monomers for the Preparation of β3‐Oligopeptides by Iterative α‐Keto AcidHydroxylamine (KAHA) Ligations
Authors: Chiang Ying‐Ling , Russak Justin A. , Carrillo Nancy , Bode Jeffrey W. 
Published: December 2012

AbstractA versatile method for the synthesis of enantiomerically pure isoxazolidine monomers for the synthesis of β3‐oligopeptides via α‐keto acidhydroxylamine (KAHA) ligation is presented. This one‐pot synthetic method utilizes in situ generated nitrones bearing gulose‐derived chiral auxiliaries for the asymmetric 1,3‐dipolar cycloaddition with methyl 2‐methoxyacrylate. The resulting enantiomerically pure isoxazolidine monomers bearing diverse side chains (proteinogenic and non‐proteinogenic) can be synthesized in either configuration (like‐ and unlike‐configured). The scalable and enantioselective synthesis of the isoxazolidine monomers enables the use of the synthesis of β3‐oligopeptides via iterative α‐keto acidhydroxylamine (KAHA) ligation.
2‐Amino‐1,2,3,6‐tetrahydro‐6‐oxocyclopenta[c]fluorene‐2‐carboxylic Acid (FlAib), a Completely Rigidified, Fluoren‐9‐one‐Based α‐Amino Acid
Authors: Wright Karen , Alvarez Antonio Blanco , Crisma Marco , Toffoletti Antonio , Formaggio Fernando , Toniolo Claudio 
Published: December 2012

AbstractThe synthesis, optical resolution, determination of absolute configuration and conformational preference, and spectroscopic characteristics of terminally protected (blocked) derivatives and short peptides of 2‐amino‐1,2,3,6‐tetrahydro‐6‐oxocyclopenta[c]fluorene‐2‐carboxylic acid (FlAib), a novel, rigid, chiral, cyclized Cα,α‐disubstituted glycine are described.
Dynamic Phenomena in Self‐Complementary {2}‐Metallocryptates Probed by Solution 133Cs‐NMR. New Insights into Ion Pairing Processes: X‐Ray Structure and Solid‐State NMR Spectra of a Meandering Species
Authors: Maid Harald , Heinemann Frank W. , Scheurer Andreas , Mooren Nicolai , Saalfrank Rolf W. , Bauer Walter 
Published: December 2012

AbstractTwo self‐complementary {2}‐metallocryptates, differing in methyl and phenyl substituents, respectively, have been studied by X‐ray analysis, and solid‐state and solution NMR. Mixed Mg/Cs metal methyl complex 2 is a linear polymer in the solid state. The two different Cs sites are confirmed by 133Cs‐solid‐state NMR. By contrast, the analog mixed Mg/Cs metal phenyl complex 4 is a meandering polymer as shown by an actual X‐ray analysis. The four non‐equivalent Cs‐sites in 4 are reflected in the solid‐state NMR spectra. Solution 133Cs‐NMR spectra of 4 reveal two independent dynamic processes: a fast exchange of Cs within contact ion‐pairs and solvent‐separated ion‐pairs (CIP, SSIP), and a slower exchange of ‘inside’ endo Cs, surrounded by three ligands, and ‘outside’ exo Cs involved in the CIP/SSIP equilibrium. Complete line‐shape analysis of variable‐temperature 133Cs‐NMR spectra of 4 yield kinetic parameters of magnified image
=10.8 kcal/mol for the fast SSIP‐CIP exchange and =13.2 kcal/mol for the slower endo/exo exchange of Cs. DOSY‐NMR Measurements confirm the monomeric nature of 4 in solution.
Enantioselective Michael Addition of the 2‐(1‐Ethylpropoxy)acetaldehyde to N‐[(1Z)‐2‐Nitroethenyl]acetamide – Optimization of the Key Step in the Organocatalytic Oseltamivir Synthesis
Authors: Hajzer Viktória , Latika Attila , Durmis Július , Šebesta Radovan 
Published: December 2012

AbstractOrganocatalytic Michael addition of alkoxyacetaldehyde 1 to N‐protected 2‐nitroethene‐1‐amine 2 (Scheme 2) is a key step in the synthesis of an important antiviral agent, oseltamivir. Screening of a large array of structurally diverse acids as potential promoters led to the identification of several useful acidic additives for this reaction (Tables 1–4). Also other reaction parameters were investigated with the aim of improving the diastereoselectivity of the Michael addition, while maintaining high enantiomer purity and yield (Tables 5 and 6).
Synthesis of AzaaromaticBorane Intramolecular Complexes by Palladium‐Catalyzed Reaction of Azaaromatic Halides with Alkynyl(triaryl)borates
Authors: Ishida Naoki , Narumi Mizuna , Murakami Masahiro 
Published: December 2012

AbstractA diversity‐oriented method to synthesize (E)‐azastilbenes having an intramolecular BN coordination bond from alkynyl(triaryl)borates and azaaromatic halides is described. The obtained π‐conjugated compounds exhibit an intense blue fluorescence and a high electron affinity, indicating their potential to be used as n‐type light‐emitting materials.
Directed MetalationCross‐Coupling Strategies. Total Syntheses of the Alleged and the Revised Phenanthrene Natural Product Gymnopusin
Authors: Wang Xin , Fu Jian‐min , Snieckus Victor 
Published: December 2012

AbstractThe total synthesis of gymnopusin (2) is described. The originally assigned structure for gymnopusin 1a was found to be incorrect by total synthesis using the Directed ortho‐Metalation (DoM)Cross‐CouplingDirected remote Metalation (DreM) sequence, a demonstrable key strategy for the regioselective construction of the 9‐phenanthrol core. The revised structure of gymnopusin (2) was confirmed by synthesis by adopting the same strategy but involving a key remote anionic Fries‐rearrangement step. Both routes highlight methodologies and concepts which may be of value in the regiocontrolled synthesis of phenanthrenoids specifically and in complex polycyclic aromatics in general.
Polyurethanes containing zwitterionic sulfobetaines and their molecular chain rearrangement in water
Authors: Cao Jun , Yang Mou , Lu Aijing , Zhai Shuying , Chen Yuanwei , Luo Xianglin 
Published: December 2012

AbstractNovel polyurethanes with zwitterionic sulfobetaines, termed PUR‐APS, were designed and synthesized by chain‐extension of biodegradable poly(ε‐caprolactone) containing N,N′‐bis (2‐hydroxyethyl) methylamine ammonium propane sulfonate (PCL‐APS) with hexamethylene diisocyanate (HDI). The bulk properties of polymers were characterized by nuclear magnetic resonance spectrum (NMR), Fourier transform infrared spectroscopy (FTIR), gel permeation chromatograph (GPC), and differential scanning calorimetry (DSC). Results showed that the polymers were successfully synthesized. Water contact angles (WCAs) and X‐ray photoelectron spectroscopy (XPS) revealed that molecular chains of the polymers rearranged after soaking in water. The amount of protein adsorption, determined by bicinchoninic acid (BCA) assay, was less than 300 ng/cm2 and decreased after hydration. The blood compatibility of the polymers was evaluated by the degree of hemolytic and activated partial thromboplastic time (APTT) and prothrombin time (PT). Results indicated that PUR‐APS polymers had good blood compatibility. Therefore, polyurethanes containing sulfobetaines have a great potential for biomedical application. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 909–918, 2013.
In‐vivo behavior of Si‐hydroxyapatite/polycaprolactone/DMB scaffolds fabricated by 3D printing
Authors: Meseguer‐Olmo Luis , Vicente‐Ortega Vicente , Alcaraz‐Baños Miguel , Calvo‐Guirado José Luis , Vallet‐Regí María , Arcos Daniel , Baeza Alejandro 
Published: December 2012

AbstractScaffolds made of polycaprolactone and nanocrystalline silicon‐substituted hydroxyapatite have been fabricated by 3D printing rapid prototyping technique. To asses that the scaffolds fulfill the requirements to be considered for bone grafting applications, they were implanted in New Zealand rabbits. Histological and radiological studies have demonstrated that the scaffolds implanted in bone exhibited an excellent osteointegration without the interposition of fibrous tissue between bone and implants and without immune response after 4 months of implantation. In addition, we have evaluated the possibility of improving the scaffolds efficiency by incorporating demineralized bone matrix during the preparation by 3D printing. When demineralized bone matrix (DBM) is incorporated, the efficacy of the scaffolds is enhanced, as new bone formation occurs not only in the peripheral portions of the scaffolds but also within its pores after 4 months of implantation. This enhanced performance can be explained in terms of the osteoinductive properties of the DBM in the scaffolds, which have been assessed through the new bone tissue formation when the scaffolds are ectopically implanted. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Snapping Up Euro Bargains with Trapped Cash
Authors: Le Guyader Louis P. 
Published: December 2012

AbstractAmerican corporations now hold well over $1.7 trillion in cash‐a record‐breaking level. But much of it is held overseas to avoid higher U.S. taxes and is called “trapped cash.” Is it time to use some of that cash to snap up what are now bargain‐priced Euro companies? Maybe it's time to “liberate” your trapped cash! © 2013 Wiley Periodicals, Inc.
The Jobs Act: Its Impact on M&A
Authors: Sherman Andrew J. , Brunsdale Shaleen 
Published: December 2012

AbstractIn April 2012, President Barack Obama signed into law the Jumpstart Our Business Startups (JOBS) Act. Its goal was to simplify or reduce the regulatory and legal hurdles faced by emerging companies and ease access to capital and investments. Although many of the implementing regulations are still pending, the passage of the JOBS Act may be able to help small and growing companies access the capital markets more efficiently‐to raise the funds needed to complete merger and acquisition (M&A) transactions. The authors discuss the new law and assess its impact. © 2013 Andrew J. Sherman and Shaleen Brunsdale
Reassessing M&A Valuation Assumptions
Authors: Pandian J. Rajendran , Woodlock Pete 
Published: December 2012

AbstractThe current economic environment has obviously created uncertainty. That uncertainty has caused many companies to focus on preserving capital. So many merger and acquisition (M'A) professionals are scratching their heads and questioning some of the fundamental assumptions that have historically driven business valuations. © 2013 Wiley Periodicals, Inc.
Detecting Fraud: What Are Auditors' Responsibilities?
Authors: Chong Gin 
Published: December 2012

AbstractHigh‐profile fraud cases have continued to make the news over the past few years. But exactly what are auditors' responsibilities when it comes to detecting fraud? The author of this article reveals that the auditing profession has come full circle‐from being responsible to not being responsible for detecting fraud. But the volume and critical nature of fraud cases remain high, as do the number of auditing standards addressing this issue. The author explores this problem in depth, identifies situations where fraud may take place, and suggests various tools that auditors should use for fraud detection. © 2013 Wiley Periodicals, Inc.
Does Multistandard Reporting Affect Analysts' Forecasts?
Authors: Yang Ya‐wen , Henry Elaine 
Published: December 2012

AbstractIn 2007, the Securities and Exchange Commission eliminated the reconciliation requirement for non‐U.S. companies that report using International Financial Reporting Standards. Has this affected the accuracy of analysts' forecasts for these companies? The authors conducted a study to find out. © 2013 Wiley Periodicals, Inc.
Mortality predictions on admission as a context for organizing care activities
Authors: Cowen Mark E. , Strawderman Robert L. , Czerwinski Jennifer L. , Smith Mary Jo , Halasyamani Lakshmi K. 
Published: December 2012

BACKGROUNDFavorable health outcomes are more likely to occur when the clinical team recognizes patients at risk and intervenes in consort. Prediction rules can identify high‐risk subsets, but the availability of multiple rules for various conditions present implementation and assimilation challenges.METHODSA prediction rule for 30‐day mortality at the beginning of the hospitalization was derived in a retrospective cohort of adult inpatients from a community hospital in the Midwestern United States from 2008 to 2009, using clinical laboratory values, past medical history, and diagnoses present on admission. It was validated using 2010 data from the same and from a different hospital. The calculated mortality risk was then used to predict unplanned transfers to intensive care units, resuscitation attempts for cardiopulmonary arrests, a condition not present on admission (complications), intensive care unit utilization, palliative care status, in‐hospital death, rehospitalizations within 30 days, and 180‐day mortality.RESULTSThe predictions of 30‐day mortality for the derivation and validation datasets had areas under the receiver operating characteristic curve of 0.88. The 30‐day mortality risk was in turn a strong predictor for in‐hospital death, palliative care status, 180‐day mortality; a modest predictor for unplanned transfers and cardiopulmonary arrests; and a weaker predictor for the other events of interest.CONCLUSIONSThe probability of 30‐day mortality provides health systems with an array of prognostic information that may provide a common reference point for organizing the clinical activities of the many health professionals involved in the care of the patient. Journal of Hospital Medicine 2013;8:229–235 © 2012 Society of Hospital Medicine