bluuebunny/crossref_metadata_2025 huggingface dataset:
Introducing Catalytic Lossen Rearrangements: Sustainable Access to Carbamates and Amines
Authors: Kreye Oliver , Wald Sarah , Meier Michael A. R.
Published: December 2012

A new, highly efficient and environmentally benign catalytic variant of the Lossen rearrangement is described. Dimethyl carbonate (DMC) as green activation reagent of hydroxamic acids in presence of catalytic amounts of tertiary amine bases {1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD), 1,8‐biazabicyclo 5.4.0 undec‐7‐ene (DBU), 1,4‐diazabicyclo[2.2.2]octane (DABCO), and triethylamine} and small quantities of methanol initiate the rearrangement. Methyl carbamates were obtained in good to moderate yields when aliphatic hydroxamic acids were employed in this catalytic Lossen rearrangement; under the same conditions aromatic hydroxamic acids yielded anilines. Notably, the mixture of DMC/methanol was recycled several times without observing decreased yields, thus minimizing the produced waste. Moreover, several other organic carbonates were successfully employed in the introduced catalytic Lossen rearrangement procedure.
Aerobic Dehydrogenative Heck Reactions of Heterocycles with Styrenes: A Negative Effect of Metallic Co‐Oxidants
Authors: Vasseur Alexandre , Harakat Dominique , Muzart Jacques , Le Bras Jean
Published: December 2012

The aerobic dehydrogenative Heck reaction (DHR) of heterocycles with styrenes was found to be more efficient in the absence of metallic co‐oxidants. According to a study of the isotope effect, the CH cleavage was the rate‐determining step of the catalytic cycle. Electrospray ionization mass spectrometry, subsequent MS/MS, and high‐resolution mass spectrometry were used to detect and characterize catalytic intermediates and species formed in the presence of metallic co‐oxidants.
Efficient and Chemoselective Reduction of Pyridines to Tetrahydropyridines and Piperidines via Rhodium‐Catalyzed Transfer Hydrogenation
Authors: Wu Jianjun , Tang Weijun , Pettman Alan , Xiao Jianliang
Published: December 2012

Promoted by iodide anion the rhodium complex dimer, [Cp*RhCl2]2, catalyzes efficiently the transfer hydrogenation of various quaternary pyridinium salts under mild conditions, affording not only piperidines but also 1,2,3,6‐tetrahydropyridines in a highly chemoselective fashion, depending on the substitution pattern at the pyridinium ring. The reduction is conducted in azeotropic formic acid/triethylamine (HCOOH‐Et3N) mixture at 40 °C, with catalyst loadings as low as 0.005 mol% being feasible.
A novel mutation in CDKN1C in sibs with Beckwith–Wiedemann syndrome and cleft palate, sensorineural hearing loss, and supernumerary flexion creases
Authors: Kantaputra Piranit Nik , Sittiwangkul Rekwan , Sonsuwan Nuntigar , Romanelli Valeria , Tenorio Jair , Lapunzina Pablo
Published: December 2012

We report on two daughters and a son of a Thai family who were affected with BWS. Their clinical findings consist of cleft palate, omphalocele, anterior ear creases, indented lesions on the posterior rim of the helix, macroglossia, posterior crossbite, and anterior open bite. The younger daughter and son had newly recognized findings of the BWS including sensorineural hearing loss and supernumerary flexion creases of the fingers. A novel mutation in CDKN1C (c.579delT; p.A193AfsX46) was found in all affected individuals and their mother. This mutation is located in the central highly polymorphic hexanucleotide repeat encoding a proline‐alanine series of repeats (PAPA‐domain). This domain is involved in MAP kinase phosphorylation. This is for the first time that sensorineural hearing loss and supernumerary flexion creases of the fingers are associated with mutation in CDKN1C. © 2012 Wiley Periodicals, Inc.
Isotopic tracing of the impact of mobility on infectious disease: The origin of people with treponematosis buried in hull, England, in the late medieval period
Authors: Roberts C.A. , Millard A.R. , Nowell G.M. , Gröcke D.R. , Macpherson C.G. , Pearson D.G. , Evans D.H.
Published: December 2012

Treponematosis has been one of the most studied and debated infectious diseases in paleopathology, particularly from the standpoint of its origin, evolution, and transmission. This study links evidence for treponematosis in skeletons from the 14th–16th century AD cemetery of the Augustinian friary of Hull Magistrates Court, England, with data from stable isotope analysis to test the hypothesis that the people with treponemal disease buried at this site were not locally born and raised. The objective is to explore the potential of using stable isotope data to track the place of origin and extent of mobility of individuals with an infectious disease. Dental enamel samples of 12 skeletons were selected for strontium (87Sr/86Sr ratio) and oxygen (δ18O) stable isotope analysis based on the presence (six ‐ diseased) or absence (six ‐ controls) of bone changes associated with treponemal disease. The oxygen isotope ratios of all but three individuals (1047, 1121, 823) overlapped at two standard deviations with the inferred local precipitation range, and only one individual (1216) had a strontium isotope ratio outside the regional range. Two of the four had probable/possible treponemal bone changes. Those with treponemal bone changes were not demonstrably more likely to be migrants than those without such lesions. However, because of extensive documentary evidence for trade with the Baltic Sea area, and for merchants from towns such as Stralsund, Danzig and Elbing being in Hull, it is very plausible that the four migrants came from the Baltic area or even southern Sweden. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.
Nutritional benefits ofcrematogaster mimosaeants andacacia drepanolobiumgum for patas monkeys and vervets in laikipia, Kenya
Authors: Isbell Lynne A. , Rothman Jessica M. , Young Peter J. , Rudolph Kathleen
Published: December 2012

Patas monkeys (Erythrocebus patas) are midsized primates that feed extensively on the gum ofAcacia drepanolobiumand the ants are housed in swollen thorns of this Acacia. Their diet resembles that expected more of smaller bodied primates. Patas monkeys are also more like smaller bodied primates in reproducing at high rates. We sought to better understand the convergence of patas monkeys with smaller bodied primates by comparing their feeding behavior on ants and gum with that of closely related, sympatric vervets (Chlorocebus pygerythrus), and analyzing the nutrient content of the gum ofA. drepanolobiumand ofCrematogaster mimosae, the most common ant species eaten by patas monkeys in Laikipia, Kenya. All occurrences of feeding and moving during focal animal sampling revealed that 1) patas monkeys seekA. drepanolobiumgum but vervets avoid it; 2) both species open swollen thorns most often in the morning when antsare less active; 3) patas monkeys continually feed onswollen thorns and gum while moving quickly throughout the day, whereas vervets reduce their consumption of these items and their travel rate at mid‐day, and; 4) vervets eat young swollen thorns at a higher rate than patas monkeys. Patas monkeys are able to spend little time acquiring substantial amounts of energy, protein, and minerals fromA. drepanolobiumgum andC. mimosaeants each day. These findings, when coupled with evidence of causes of infant and adult female mortality, suggest that reproductive success of female patas monkeys is more immediately affected by illness, disease, interactions between adults and infants, and access to water than by food. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.
Comparative histomorphology of intrinsic vibrissa musculature among primates: implications for the evolution of sensory ecology and “face touch”
Authors: Muchlinski Magdalena N. , Durham Emily L. , Smith Timothy D. , Burrows Anne M.
Published: December 2012

Macrovibrissae are specialized tactile sensory hairs present in most mammalian orders, used in maxillary mechanoreception or “face touch.” Some mammals have highly organized vibrissae and are able to “whisk” them. Movement of vibrissae is influenced by intrinsic vibrissa musculature, striated muscle bands that attach directly to the vibrissa capsule. It is unclear if primates have organized vibrissae or intrinsic vibrissa musculature and it is uncertain if they can move their vibrissae. The present study used histomorphological techniques to compare vibrissae among 19 primates and seven non‐primate mammalian taxa. Upper lips of these mammals were sectioned and processed for histochemical analysis. While controlling for phylogenetic effects the following hypotheses were tested: 1) mammals with well‐organized vibrissae possess intrinsic vibrissa musculature and 2) intrinsic vibrissa musculature is best developed in nocturnal, arboreal taxa. Our qualitative analyses show that only arboreal, nocturnal prosimians possess intrinsic musculature. Not all taxa that possessed organized vibrissae had intrinsic vibrissa musculature. Phylogenetic comparative analyses revealed a 70% probability that stem mammals, primates, and haplorhines possessed intrinsic vibrissa musculature and well‐organized vibrissae. These two traits most likely coevolved according to a discrete phylogenetic analysis. These results indicate that nocturnal, arboreal primates have the potential to more actively use their vibrissae in spatial recognition and navigation tasks than diurnal, more terrestrial species, but there is a clear phylogenetic signal involved in the evolution of primate vibrissae and “face touch.” Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.
Preparation and catalytic use of platinum in magnetic core/shell nanocomposites
Authors: Darwish M. S. A. , Kunz U. , Peuker U.
Published: December 2012

Platinum (Pt) nanoparticles show high activity as catalysts in various chemical reactions. The control of the morphology of Pt nanostructures can provide an opportunity to improve their catalytic properties. The preparation of Pt‐loaded iron‐oxide polyvinylbenzyl chloride nanocomposites was done in several stages: first by the formation of the core consisting of magnetite nanoparticles and second by the polymerization of vinylbenzyl chloride in the presence of the magnetic core particles. The third step is the amination of the chlorine group with ammonia, which leads to an ion exchange resin. Then, the Pt precursor (H2PtCl6) is attached by ion exchange. Finally, the Pt ions are reduced to Pt metal with NaBH4. The obtained material can be dispersed easily and be used as a catalyst which can be separated after the reaction by magnetic fields. Characterization of the resulting metallic nanocomposites is evaluated by atomic absorption spectroscopy, thermal gravimetric analysis, transmission electron microscopy, infrared spectroscopy, and gas chromatography. The activity of Pt at magnetic core/shell nanocomposites was measured for the reduction reaction of cinnamaldehyde to cinnamyl alcohol. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and characterization of unsaturated polyester/carborundum composites
Authors: Asaad Jeannette N.
Published: December 2012

Two unsaturated polyesters, one based on phthalic anhydride PEP and the other based on isophthalic acid PEI, were synthesized. The chemical structure of the two polyesters was characterized by IR and 1H and 13C NMR spectroscopy. The effect of styrene concentration on the curing of polyesters was also studied. It has been found that the percent of polyester/styrene (70/30 wt %) gave the highest percent of curing. Different concentrations of carborundum (0–70 wt %) were used to prepare polyester composites. A comparative study was done on the properties of the two prepared polyesters PEP and PEI and their composites in term of their thermal, mechanical, electrical, and physical properties. The results indicate that the polyester based on isophthalic acid (PEI) and its composites gave higher compressive strength values and lower water absorption than those based on phthalic anhydride (PEP). The presence of carborundum improved the thermal stability than the cured polyesters and electrical properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis of PS‐g‐POSS hybrid graft copolymer by click coupling via ”graft onto” strategy
Authors: Niu Maoshan , Li Tao , Xu Riwei , Gu Xiaoyu , Yu Dingsheng , Wu Yixian
Published: December 2012

Polystyrene (PS)‐incorporated polyhedral oligomeric silsesquioxanes (POSS) organic–inorganic hybrid graft copolymer could be achieved by click coupling reaction between alkyne groups in POSS and azido groups in PS via “graft onto” strategy. Alkyne‐functionalized POSS was synthesized via thiol‐ene facile click reaction and subsequent amidation reaction with very high yield. Azido‐multifunctionalized PS could be synthesized by chloromethylation and subsequent azido reaction. The chemical structures of PS‐(CH2Cl)m, PS‐(CH2N3)m, and PS‐g‐POSS were determined by Fourier transform infrared and 1H NMR characterization. PS‐g‐POSS presented a better hydrophobic property with contact angle of 113° than that of PS (85°). And PS‐g‐POSS with ≤5% of grafting degree had lower glass transition temperature (Tg) than that of PS and then it increased up to 112°C with grafting degree. An obvious aggregation of POSS phase with 10–80 nm in size was formed in PS‐g‐POSS matrix. In addition, 5 wt % of PS‐g‐POSS was added to general purpose polystyrene (GPPS) to remarkably improve its tensile strength from 45 to 57 MPa. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Study on the effect of plasma treatment of woven polyester fabrics with respect to nisin adsorption and antibacterial activity
Authors: Kerkeni Ahmed , Behary Nemeshwaree , Dhulster Pascal , Chihib Nour‐Eddine , Perwuelz Anne
Published: December 2012

The effect of plasma treatment of polyester (PET) fabric with respect to nisin adsorption and antibacterial activity was studied. Both cleaned untreated PET fabric and plasma‐treated PET fabric were separately dipped in aqueous nisaplin solution with 0.5 and 1% of nisin, for 24 h under stirring, and then dried. With 1% of nisin, high and immediate antibacterial activity against Staphylococcus aureus was observed, and this activity was maintained even after 24 h. However, with 0.5% of nisin, no immediate bacterial reduction was observed, and only the untreated PET fabric exhibited antibacterial activity after 24 h. Only nisin molecules which can diffuse from the fabric can impart antibacterial activity, as demonstrated by the absence of bacterial inhibition zone after complete removal of releasable nisin in water. The desorption capacity of nisin from the fabric into water was monitored by tensiometry, while the presence of residual strongly sorbed nisin on the fabric was confirmed by wettability, zeta potential measurements, and wash durability test after nisin coloration by a protein dye. Plasma treatment, which increases the hydrophilic behavior of the PET fabric (WCA reduced from 80° to 42°), increases considerably the quantities of strongly and weakly sorbed nisin. However, it does not improve antibacterial activity compared to the PET fabric without plasma treatment. The reduced mobility of the nisin molecules due to chemisorption of the first layers of nisin on the plasma treated PET fabric can explain the reduced antibacterial activity with 0.5% nisin. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
A new method for the prediction of diffusion coefficients in poly(ethylene terephthalate)
Authors: Welle Frank
Published: December 2012

Poly(ethylene terephthalate) (PET) is used in several packaging applications, especially for beverages. Due to the low concentration of potential chemical compounds like polymer additives or monomers leached out of the polymers and found in food or beverages, the compliance of a PET packaging material is shown often by use of migration modeling. Diffusion coefficients for migrants, however, are rare in the scientific literature. The aim of the study was to develop an equation for the prediction of diffusion coefficients in PET on the basis of activation energies of diffusion for possible migrants in PET. As a result, a correlation between experimentally determined activation energies of diffusion EA and the volume of the migrant V was established for PET. In addition, a correlation of the pre‐exponential factor D0 with the activation energy EA was found. Combining both correlations lead to an equation where the diffusion coefficients DP are predictable from the molecular volume V of the migrant. The equation might be useful for migration prediction and consumer exposure estimations. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of organic modification on structure and properties of room‐temperature vulcanized silicone rubber/montmorillonite nanocomposites
Authors: Jincheng Wang , Wenli Hao
Published: December 2012

The aim of this work was to study the effect of different organomontmorillonite on the structure and properties of room‐temperature vulcanized silicone rubber (RTV) composites. Quaternary ammonium salts (QAS) and hyperbranched QAS were used as intercalation agents to treat Na+‐montmorillonite and formed two kinds of organomontmorillonite, OMMT and HOMMT. OMMT/RTV and HOMMT/RTV composites were prepared using these organomodified silicate layers. Properties such as tensile strength, elongation at break, swelling behavior, and thermal stability were researched and compared. The addition of OMMT and HOMMT improved the mechanical properties of RTV composites. The composites with 3 mass % HOMMT showed the highest tensile strength and elongation at break, 5.4 MPa and 425%, which was 29 and 97% higher than that of pure RTV. The RTV composites exhibited excellent thermal stability and swelling behavior. At loading of 3 mass % of HOMMT, Tonset, and Tmax was 452 and 640°C, respectively, 33 and 150°C higher than that of pure RTV. A combination of X‐ray diffraction (XRD) test, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies was used to characterize the structure and reinforcing mechanism of these clays. The diffraction peaks in XRD curves were almost absent in the scattering curve of RTV/HOMMT (3 mass %). This was due to the possibility of having exfoliated silicate layers dispersed in the polymer matrix. A careful observation of an area of platelet tactoid of 3% HOMMT filled composite in SEM and TEM revealed the uniform dispersion of the silicate layers in the composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Copolymerization of ethylene with unsaturated alcohols and methylmethacrylate using a silylated α‐diimine nickel catalyst: Molecular modeling and photodegradation studies
Authors: Matos Inês , Fernandes Susete N. , Liu Hua‐Rong , Tevtia Amit K. , Singh R. P. , Lemos MANDA , Lemos Francisco , Marques Maria M.
Published: December 2012

In this article, the experimental results obtained in the copolymerization of ethylene with polar monomers using a silylated α‐diimine nickel catalyst are described and compared with those obtained with a non‐silylate similar one. The results show that the introduction of a siliyl group in the para‐position of the imine moiety turns the catalyst less sensitive toward polar functionalities. However, the reactivity observed in copolymerization reactions was found to be reduced both the global polymerization and incorporation rates. Molecular modeling calculation allowed us to understand both the preferred insertion mode and the intermediate product structures for E/MMA copolymerization. Photodegradation studies showed that the presence of polar groups in the copolymers increases their rate of oxidation and turn them more easily degradable. The stabilization performed by Tinuvin 770 showed that for long‐exposure times, it is not very effective regardless it is only mixed or grafted to the copolymer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and characterization of cyhalothrin‐loaded poly(2‐hydroxyethyl methacrylate)‐co‐polylactide (PHEMA‐co‐PLA) ultrafine particles
Authors: Fan Tengfei , Wu Xuemin , Wu Yan
Published: December 2012

Poly(2‐hydroxyethyl methacrylate)‐co‐polylactide (PHEMA‐co‐PLA) and its corresponding cyhalothrin‐loaded ultrafine particles were successfully synthesized and prepared, respectively. The chemical structures of the copolymers have been confirmed by Fourier transform infrared spectroscopy (FTIR), 1H‐nuclear magnetic resonance (1H‐NMR), 13C‐nuclear magnetic resonance (13C‐NMR), and thermogravimetric analysis (TGA). Furthermore, the particle size, the cyhalothrin loading content (LC), and the cyhalothrin release behavior were investigated. PHEMA‐co‐PLA proved to be a good material for the preparation of ultrafine particles for lipophilic pesticide delivery. The developed cyhalothrin‐loaded PHEMA‐co‐PLA ultrafine particles showed good dispersity in water and sustained release behavior. In addition, it is easy to be prepared by both nanoprecipitation method and emulsion/solvent evaporation method. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Conformational, thermal, and ionic conductivity behavior of PEO in PEO/PMMA miscible blend: Investigating the effect of lithium salt
Authors: Ghelichi Mahdi , Qazvini Nader Taheri , Jafari Seyed Hassan , Khonakdar Hossein Ali , Farajollahi Yaser , Scheffler Christina
Published: December 2012

In this research, influence of incorporating LiClO4 salt on the crystallization, conformation, and ionic conductivity of poly(ethylene oxide) (PEO) in its miscible blend with poly(methyl methacrylate) (PMMA) is studied. Differential scanning calorimetry showed that the incorporation of salt ions into the blend suppresses the crystallinity of PEO. The X‐ray diffraction revealed that the unit‐cell parameters of the crystals are independent of the LiClO4 concentration despite of the existence of ionic interactions between PEO and Li cations. In addition, the complexation of the Li+ ions by oxygen atoms of PEO is investigated via Fourier transform infrared spectroscopy. The conformational changes of PEO segments in the presence of salt ions are studied via Raman spectroscopy. It is found that PEO chains in the blend possess a crown‐ether like conformation because of their particular complexation with the Li+ ions. This coordination of PEO with lithium cations amorphize the PEO and is accounted for suppressed crystallinity of PEO in the presence of salt ions. Finally, electrochemical impedance spectroscopy is used to characterize the ionic conductivity of PEO in the PEO/PMMA/LiClO4 ternary mixture at various temperatures. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Enhancing particle erosion resistance of glass‐reinforced polymeric composites using carbon nanofiber‐based nanopaper coatings
Authors: Zhang Na , Yang Fan , Guerra Dante , Shen Changyu , Castro Jose , Lee James Ly
Published: December 2012

Sand erosion may cause severe damage of blades in wind turbine and helicopter blades as well as many surface components of airplanes. In this study, thin nanopapers made of carbon nanofibers (CNFs) are used to enhance the resistance of solid particle erosion of glass fiber (GF)/wind epoxy composites. Finite element computer simulations are used to elucidate the underlying mechanisms. The much higher particle erosion resistance of nanopapers compared to GF‐reinforced epoxy composites is attributed to the high strength of CNFs and their nanoscale structure. The excellent performance in particle erosion resistance makes the CNF‐based nanopaper a prospective protective coating material for the turbine blades in the wind energy industry. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Microwave assisted glycolysis of poly(ethylene terepthalate) for preparation of polyester polyols
Authors: Chaudhary Saurabh , Surekha Parthasarathy , Kumar Devendra , Rajagopal Chitra , Roy Prasun Kumar
Published: December 2012

The generic aim of the present work is to reduce the time required for glycolytic depolymerization of PET by employing microwave irradiation instead of the conventional heating process. Glycolysis of PET was performed in the presence of glycols of different molecular weight under microwave irradiation. Experimental conditions like PET : glycol ratio, reaction time and concentration of glycerol were optimized to maximize the product yield. In the presence of ethylene glycol, bis‐(hydroxyethyl) terephthalate (BHET) could be obtained in excellent yields in significantly lesser time (30 min) as compared to 8–9 h by conventional heating process. The BHET yield could further be increased by a second step glycolysis of the residual oligomers. This increased efficiency of the microwave assisted process has been attributed to the high microwave absorption capacity of glycols which results from their high loss factor. PET could also be glycolysed in the presence of higher glycols, however the reactivity of diols was found to decrease with increase in the molecular weight. The polyols obtained were reacted with aromatic diphenylmethane diisocyanate to prepare polyurethane foams, which were characterized by various techniques for determination of their physical, mechanical and structural properties. The compressive strength of the polyurethane foams was found to be inversely proportional to the molecular weight of the glycolysed polyol used for its preparation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Practical Synthesis of (20S)‐10‐(3‐Aminopropyloxy)‐7‐ethylcamptothecin, a Water‐Soluble Analogue of Camptothecin
Authors: Watanabe Tatsuya , Tsuboi Yasunori , Nomura Sumihiro
Published: December 2012

A robust, practical synthesis of (20S)‐10‐(3‐aminopropyloxy)‐7‐ethylcamptothecin (T‐2513, 5), which is a water‐soluble analogue of camptothecin, has been developed. The key step in this synthesis is a highly diastereoselective ethylation at the C20 position by using N‐arylsulfonyl‐(R)‐1,2,3,4‐tetrahydroisoquinoline‐3‐carboxylic acid ester as a chiral auxiliary, which affords the key intermediate ethyl‐(S)‐2‐acyloxy‐2‐(6‐cyano‐5‐oxo‐1,2,3,5‐tetrahydroindolizin‐7‐yl)butanoate (8 k) in 93 % yield and 87 % de. Optically pure compound 8 k was obtained by a single recrystallization from acetone and its further elaboration through Friedlander condensation afforded compound 5. This synthesis does not require any chromatographic purification steps and can provide compound 5 on a multi‐gram scale in 6.3 % overall yield (16 steps).
An approach for identifying and predicting economic recessions in real‐time using time–frequency functional models
Authors: Holan Scott H. , Yang Wen‐Hsi , Matteson David S. , Wikle Christopher K.
Published: December 2012

Identifying periods of recession and expansion is a challenging topic of ongoing interest with important economic and monetary policy implications. Given the current state of the global economy, significant attention has recently been devoted to identifying and forecasting economic recessions. Consequently, we introduce a novel class of Bayesian hierarchical probit models that take advantage of dimension‐reduced time–frequency representations of various market indices. The approach we propose can be viewed as a Bayesian mixed frequency data regression model, as it relates high‐frequency daily data observed over several quarters to a binary quarterly response indicating recession or expansion. More specifically, our model directly incorporates time–frequency representations of the entire high‐dimensional non‐stationary time series of daily log returns, over several quarters, as a regressor in a predictive model, while quantifying various sources of uncertainty. The necessary dimension reduction is achieved by treating the time–frequency representation (spectrogram) as an “image” and finding its empirical orthogonal functions. Subsequently, further dimension reduction is accomplished through the use of stochastic search variable selection. Overall, our dimension reduction approach provides an extremely powerful tool for feature extraction, yielding an interpretable image of features that predict recessions. The effectiveness of our model is demonstrated through out‐of‐sample identification (nowcasting) and multistep‐ahead prediction (forecasting) of economic recessions. In fact, our results provide greater than 85% and 80% out‐of‐sample forecasting accuracy for recessions and expansions respectively, even three quarters ahead. Finally, we illustrate the utility and added value of including time–frequency information from the NASDAQ index when identifying and predicting recessions. Copyright © 2012 John Wiley & Sons, Ltd.
New bis‐ferrocenyl end‐capped peptides: synthesis and charge transfer properties
Authors: Donoli Alessandro , Marcuzzo Vanessa , Moretto Alessandro , Crisma Marco , Toniolo Claudio , Cardena Roberta , Bisello Annalisa , Santi Saverio
Published: December 2012

In this article, the successful preparation of a new series of 310‐helical peptides of different length containing two terminal ferrocenyl (Fc) units and based on the strongly foldameric α‐aminoisobutyric (Aib) acid is reported. The synthesis of the FcCO(Aib)nNHFc (n = 1−5) homo‐peptides was performed by solution methods. Moderate to good yields (26−85%) were obtained in each of the difficult coupling steps of FcCOOH and the corresponding H(Aib)nNHFc compounds by C‐activation with the 1‐(3‐dimethylaminopropyl)‐3‐ethylcarbodiimide/7‐aza‐1‐hydroxy‐1,2,3‐benzotriazole method. Information on the CO···HN intramolecularly hydrogen‐bonded networks was initially obtained from FT‐IR absorption measurements. The NH stretching (amide A) region allowed us to distinguish which amide protons are involved in intramolecular hydrogen bonds and indicates the formation of an incipient 310‐helix structure for peptides containing at least two Aib residues. This conclusion was confirmed by 1H NMR titrations of the NH groups of the peptides in CDCl3 with dimethylsulfoxide and by crystallographic analysis of the Nα‐acylated FcCO(Aib)5NHFc pentapeptide amide. The two redox‐active Fc groups covalently bound to the termini of the foldameric peptide architectures were used as electrochemical probes. The end‐to‐end effects of electron holes generated by single and double oxidations were analyzed by means of electrochemical and spectroelectrochemical techniques. The results of these studies indicate that charge transfer across the peptide main chain does occur in the five peptides. In particular, in the pentapeptide 5, charge is transferred through an intramolecular Fe···Fe separation of 14 Å. © 2012 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 100: 71–81, 2013.
Changes in chemistry and biochemistry education: Creative responses to medical college admissions test revisions in the age of the genome
Authors: Brenner Charles
Published: December 2012

Approximately two million students matriculate into American colleges and universities per year. Almost 20% of these students begin taking a series of courses specified by advisers of health preprofessionals. The single most important influence on health profession advisers and on course selection for this huge population of learners is the Medical College Admissions Test (MCAT), which was last revised in 1991, 10 years before publication of the first draft human genome sequence. In preparation for the 2015 MCAT, there is a broad discussion among stakeholders of how best to revise undergraduate and medical education in the molecular sciences to prepare researchers and doctors to acquire, analyze and use individual genomic and metabolomic data in the coming decades. Getting these changes right is among the most important educational problems of our era. © 2012 by The International Union of Biochemistry and Molecular Biology, 41(1):1–4, 2013
Development of sensory neuropathy in streptozotocin‐induced diabetic mice
Authors: Murakami Tatsufumi , Iwanaga Takayuki , Ogawa Yoshinao , Fujita Yoshiaki , Sato Eiji , Yoshitomi Hironori , Sunada Yoshihide , Nakamura Akihiro
Published: December 2012

Diabetic polyneuropathy is a major complication of diabetes and the most common cause of peripheral neuropathy. Sensory‐dominant neuropathy is the most common type. We previously used streptozotocin (STZ)‐induced diabetic ddY mice with sensory neuropathy to evaluate the therapeutic effects of vascular endothelial growth factor and placental growth factor isoforms. In this study, to characterize the development of diabetic sensory neuropathy, electrophysiological, behavioral, and histopathological studies were performed in these diabetic mice. A significant difference in sensory conduction velocity in the tail nerve was observed between healthy and diabetic mice at 1 week after STZ injection. Diabetic mice developed hypoalgesia at 5 weeks after STZ injection. Axon area and myelin thickness of the myelinated fibers were increased in 17‐week‐old healthy mice compared with those in 8‐week‐old healthy mice. However, these increases were retarded in 17‐week‐old diabetic mice. In unmyelinated fibers, axon area was significantly reduced in 17‐week‐old diabetic mice compared with 8‐ and 17‐week‐old healthy mice. These findings suggest that both impaired maturation of myelinated fibers and atrophy of unmyelinated fibers simultaneously occur in the early stage of diabetes in these mice. Our mouse model may be useful for studying the pathogenesis of and therapies for diabetic sensory neuropathy.
Bystanders' Support of Cyberbullied Schoolmates
Authors: Macháčková Hana , Dedkova Lenka , Sevcikova Anna , Cerna Alena
Published: December 2012

This study examined factors that increase or decrease the support a bystander offered to a victim of cyberbullying. Possible determinants of supportive behaviour were analyzed using a four‐step hierarchical regression analysis on data from 156 Czech children (12–18 years old; M = 15.1; 54% females) who witnessed their schoolmates being victims of cyberbullying. Among individual characteristics, only a general tendency toward prosocial behaviour was a positive predictor of supportive behaviour. Other factors such as age, gender, self‐esteem, and problematic relationships with peers had no effect. Among contextual factors, existing relationships with the victim, upset feelings evoked by witnessing victimization, and direct requests for help from the victim triggered supportive behaviour, while strong relationships with the bully inhibited it. Fear of intervening played no role. The practical implications of the findings are discussed with regard to the roles of the emotional response of the bystander and direct requests for help from the victim in cyberbullying interventions. Copyright © 2012 John Wiley & Sons, Ltd.
A Modular Synthesis of Teraryl‐Based α‐Helix Mimetics, Part 2: Synthesis of 5‐Pyridine Boronic Acid Pinacol Ester Building Blocks with Amino Acid Side Chains in 3‐Position
Authors: Peters Martin , Trobe Melanie , Breinbauer Rolf
Published: December 2012

One of the most common protein–protein interactions (PPI) is the interaction of the α‐helix of one protein with the surface of the second one. Terphenylic scaffolds are bioinspired motifs in the inhibition of PPIs and have been identified as suitable α‐helix mimetics. One of the challenging aspects of this strategy is the poor solubility of terphenyls under physiological conditions. In the literature pyrrolopyrimidine‐, pyrimidine‐ or pyridazine‐based mimetics have been reported to show improved solubility. We present a new convergent strategy for the synthesis of linear pyridine‐type teraryls based on a phenylic core unit. A general approach for the synthesis of 3,5‐disubstituted pyridine‐based boronic acid pinacol esters with amino acid side chains in the 3‐position (representing Phe, Leu, Ile, Lys, Asp, Asn) is presented and exploits the functional group tolerance of the Knochel–Grignard reagents. The building blocks have been used in a convergent in situ two‐step synthesis of teraryl α‐helix mimetics.
Sulfinylnitriles: Sulfinyl–Metal Exchange–Alkylation Strategies
Authors: Nath Dinesh , Fleming Fraser F.
Published: December 2012

Adding organolithiums, Grignard reagents, or zincates to sulfinylnitriles triggers a facile sulfinyl–metal exchange to afford N‐ or C‐metalated nitriles. Sulfinyl–magnesium exchange–alkylations efficiently install quaternary and tertiary centers, even in the case of tertiary sulfinylnitriles that contain a highly acidic methine proton. α‐Sulfinylalkenenitriles afford moderately nucleophilic magnesiated nitriles, and the reactivity can be dramatically increased by conversion to the corresponding magnesiates. The sulfinyl‐metal exchange is extremely fast, proceeds efficiently with quaternary, tertiary, and vinylic α‐sulfinylnitriles, and exhibits an exceptional functional group tolerance in nitrile alkylations.
Efficient Synthesis of a Regioregular Oligothiophene Photovoltaic Dye Molecule, MK‐2, and Related Compounds: A Cooperative Hypervalent Iodine and Metal‐Catalyzed Synthetic Route
Authors: Dohi Toshifumi , Yamaoka Nobutaka , Nakamura Shota , Sumida Kohei , Morimoto Koji , Kita Yasuyuki
Published: December 2012

We have successfully established an efficient route to the core structure of donor–acceptor head‐to‐tail (H–T)‐linked regioregular oligothiophenes, which includes the following key synthetic steps, that is, hypervalent iodine induced direct and regioselective coupling of thiophenes and the use of the obtained bithiophenes as excellent coupling substrates for the Suzuki and Stille couplings. The versatility of this new approach is highlighted in the dramatic improvement of the yield (ca. 59 % overall yield) of MK‐2, a high‐performance organic dye, for photovoltaic applications.
Computational Design, Synthesis, and Mechanochromic Properties of New Thiophene‐Based π‐Conjugated Chromophores
Authors: Prampolini Giacomo , Bellina Fabio , Biczysko Malgorzata , Cappelli Chiara , Carta Luciano , Lessi Marco , Pucci Andrea , Ruggeri Giacomo , Barone Vincenzo
Published: December 2012

The possibility of exploiting supramolecular architectures for the preparation of innovative mechanochromic devices has been extended by designing novel thienyl‐substituted 1,4‐bis(ethynyl)benzene dyes, which are characterized by a conjugated, rigid, rodlike core structure. This new family of chromophores was synthesized according to a simple two‐step sequential cross‐coupling reaction, and the optical properties were investigated in solution and in a polymeric matrix. To tune the mechanochromic performances in smart polymer materials, a virtual screening was set up that was able to select a derivative with optimal spectral features. The effective combination of experimental and computational investigations allowed us to spot those homologues with already potential anisotropic and aggregachromic features and characterized by the best spectral properties and luminescent response. The best candidate was synthesized and dispersed into a polyethylene matrix, indeed achieving an “in silico designed” mechanochromic material. Besides the specific applications of this novel material, the integration of computational and experimental techniques reported here defines an efficient protocol that can be applied to make a selection among similar dye candidates, which constitute the essential responsive part of such supramolecular devices.
Fully Synthetic Self‐Adjuvanting Thioether‐Conjugated GlycopeptideLipopeptide Antitumor Vaccines for the Induction of Complement‐Dependent Cytotoxicity against Tumor Cells
Authors: Cai Hui , Sun Zhan‐Yi , Huang Zhi‐Hua , Shi Lei , Zhao Yu‐Fen , Kunz Horst , Li Yan‐Mei
Published: December 2012

Glycopeptides of tumor‐associated mucin MUC1 are promising target structures for the development of antitumor vaccines. Because these endogenous structures were weakly immunogenic, they were coupled to immune‐response‐stimulating T‐cell epitopes and the Pam3Cys lipopeptide to induce strong immune responses in mice. A new thioether‐ligation method for the synthesis of two‐ and three‐component vaccines that contain MUC1 glycopeptides as the B‐cell epitopes, a T‐cell epitope peptide, and the Pam3CSK4 lipopeptide is described. The resulting fully synthetic vaccines were used for the vaccination of mice, either in a liposome with Freund′s adjuvant or in aqueous PBS buffer. The three‐component vaccines that contained the Tetanus Toxoid P2 T‐cell epitope peptide induced strong immune responses, even when administered just in PBS. By activation of the complement‐dependent cytotoxicity (CDC) complex, the antisera induced the killing of tumor cells.
Structural Observations of Heterometallic Uranyl Copper(II) Carboxylates and Their Solid‐State Topotactic Transformation upon Dehydration
Authors: Olchowka Jakub , Falaise Clément , Volkringer Christophe , Henry Natacha , Loiseau Thierry
Published: December 2012

The hydrothermal reactions of uranyl nitrate and metallic copper with aromatic polycarboxylic acids gave rise to the formation of five heterometallic UO22+Cu2+ coordination polymers: (UO2)Cu(H2O)2(1,2‐bdc)2 (1; 1,2‐bdc=phthalate), (UO2)Cu(H2O)2(btec)⋅4 H2O (2) and (UO2)Cu(btec) (2′; btec=pyromellitate), (UO2)2Cu(H2O)4(mel) (3; mel=mellitate), and (UO2)2O(OH)2Cu(H2O)2(1,3‐bdc)⋅H2O (4; 1,3‐bdc=isophthlalate). Single‐crystal X‐ray diffraction (XRD) analysis of compound 1 revealed 2D layers of chains of UO8 and CuO4(H2O)2 units that were connected through the phthalate ligands. In compound 2, these sheets were connected to each other through the two additional carboxylate arms of the pyromellitate, thus resulting in a 3D open‐framework with 1D channels that trapped water molecules. Upon heating, free and bonded water species (from CuOH2) were evacuated from the structure. This thermal transition was followed by in situ XRD and IR spectroscopy. Heating induced a solid‐state topotactic transformation with the formation of a new set of CuO interactions in the crystalline anhydrous structure (2′), in order to keep the square‐planar environment around the copper centers. The structure of compound 3 was built up from trinuclear motifs, in which one copper center, CuO4(OH2)2, was linked to two uranium units, UO5(H2O)2. The assembly of this trimer, “U2Cu”, with the mellitate generated a 3D network. Complex 4 contained a tetranuclear uranyl core of UO5(OH)2 and UO6(OH) units that were linked to two copper centers, CuO(OH)2(H2O)2, which were then connected to each other through isophthalate ligands and UOCu interactions to create a 3D structure. The common structural feature of these different compounds is a bridging oxo group of UOCu type, which is reflected by apical CuO distances in the range 2.350(3)–2.745(5) Å. In the case of a shorter CuO distance, a slight lengthening of the uranyl bond (UO) is observed (e.g., 1.805(3) Å in complex 4).
Decarboxylative Alkylation of β‐Keto Acids with Isochromans under Oxidative Conditions
Authors: Chen Yan , Tian Shi‐Kai
Published: December 2012

An unprecedented decarboxylative alkylation reaction of β‐keto acids with isochromans has been developed under oxidative conditions. A range of β‐keto acids smoothly undergo decarboxylative alkylation with isochromans in the presence of 2,2,6,6‐tetramethylpiperdine‐1‐oxoammonium hexafluorophosphate to give structurally diverse 1‐acylmethylisochromans in moderate to excellent yields with extremely high regioselectivity.
A Scalable Synthesis of 6,19‐Dihydroxyandrostenedione
Authors: Yan Yubo , Li Ting , Liu Tao , Dou Qingyu , Ding Kai , Tian Weisheng
Published: December 2012

Starting from the commercially available 19‐hydroxyandrostenedione, a practical protocol for the preparation of 6,19‐dihydroxyandrostenedione is reported. This compound is a key intermediate for the synthesis of cyclocitrinols. With the stereospecific epoxidation and following isomerization to allylic alcohol as key steps, a six‐step procedure provided desired product in high yield. The sequence is easy to scale‐up without the need of laborious chromatography.
Design and Rationale of the PRAGUE‐12 Trial: A Large, Prospective, Randomized, Multicenter Trial That Compares Cardiac Surgery With Left Atrial Surgical Ablation With Cardiac Surgery Without Ablation in Patients With Coronary and/or Valvular Heart Disease Plus Atrial Fibrillation
Authors: Straka Zbyněk , Budera Petr , Osmančík Pavel , Vaněk Tomáš , Hulman Michal , Šmíd Michal , Malý Marek , Widimský Petr
Published: December 2012

Surgical ablation procedure can restore sinus rhythm (SR) in patients with atrial fibrillation (AF) undergoing cardiac surgery. However, it is not known whether it has any impact on clinical outcomes. There is a need for a randomized trial with long‐term follow‐up to study the outcome of surgical ablation in patients with coronary and/or valve disease and AF. Patients are prospectively enrolled and randomized either to group A (cardiac surgery with left atrial ablation) or group B (cardiac surgery alone). The primary efficacy outcome is the SR presence (without any AF episode) during a 24‐hour electrocardiogram after 1 year. The primary safety outcome is the combined end point of death, myocardial infarction, stroke, and renal failure at 30 days. Long‐term outcomes are a composite of total mortality, stroke, bleeding, and heart failure at 1 and 5 years. We finished the enrollment with a total of 224 patients from 3 centers in 2 countries in December 2011. Currently, the incomplete 1‐year data are available, and the patients who enrolled first will have their 5‐year visits shortly. PRAGUE‐12 is the largest study to be conducted so far comparing cardiac surgery with surgical ablation of AF to cardiac surgery without ablation in an unselected population of patients who are operated on for coronary and/or valve disease. Its long‐term results will lead to a better recognition of ablation's potential clinical benefits.

The PRAGUE‐12 trial is partially funded by the Charles University Research Projects MSM0021620817 and UNCE 204010/2012.

The authors have no other funding, financial relationships, or conflicts of interest to disclose.
Milestones in Pediatric Cardiology: Making Possible the Impossible
Authors: Mormile Raffaella , Quadrini Ilaria , Squarcia Umberto
Published: December 2012

Pediatric Cardiology as a discipline has been proposed to have been born on August 26, 1938, when Robert Gross at the age of 33 years, successfully ligated a patent ductus arteriosus of a 7 years girl at the Children's Hospital in Boston. In November 1944, Helen Taussig convinced Alfred Blalock to anastomose the left subclavian artery to the left pulmonary artery after Robert Gross had declined to cooperate with her. About the 1950s, at the University of Minneapolis, Clarence Walton Lillehei worked on a controlled “crossed circulation” in which the cardiopulmonary bypass machine was another human, generally one of the patient's parents. In 1966 Williams Rashkind introduced ballon septostomy as a palliative approach to complete transposition of the Great Arteries, followed later by Jean Kan's balloon valvuloplasty to open the pulmonary valve. During the 1960s Giancarlo Rastelli developed a new classification of the Atrio Ventricular Canal defect which allowed to have a strikingly better surgical results. Today, even the hypoplastic left heart syndrome (HLHS), at one time a fatal condition, is operable. The completion of the Human Genome Project has been an enormous help in the understanding the genetic causes of cardiac anomalies. However, there are very few approved application for stem cells, and stem cells will not likely replace organ transplantation any time soon. Recently, the protein survivin has been described as a novel player in cardioprotection against myocardial ischemia/reperfusion injury. The science needs to be made with love to warrant the humanity of Research.

The authors have no funding, financial relationships, or conflicts of interest to disclose.