bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlled Nanopatterning of a Polymerized Ionic Liquid in a Strong Electric Field
Authors: Bocharova Vera , Agapov Alexander L. , Tselev Alexander , Collins Liam , Kumar Rajeev , Berdzinski Stefan , Strehmel Veronika , Kisliuk Alexander , Kravchenko Ivan I. , Sumpter Bobby G. , Sokolov Alexei P. , Kalinin Sergei V. , Strelcov Evgheni
Published: December 2014

Nanolithography has become a driving force in advancements of the modern day's electronics, allowing for miniaturization of devices and a steady increase of the calculation, power, and storage densities. Among various nanofabrication approaches, scanning probe techniques, including atomic force microscopy (AFM), are versatile tools for creating nanoscale patterns utilizing a range of physical stimuli such as force, heat, or electric field confined to the nanoscale. In this study, the potential of using the electric field localized at the apex of an AFM tip to induce and control changes in the mechanical properties of an ion containing polymer—a polymerized ionic liquid (PolyIL)—on a very localized scale is explored. In particular, it is demonstrated that by means of AFM, one can form topographical features on the surface of PolyIL‐based thin films with a significantly lower electric potential and power consumption as compared to nonconductive polymer materials. Furthermore, by tuning the applied voltage and ambient air humidity, control over dimensions of the formed structures is reproducibly achieved.
Bioinspired Magnetite Crystallization Directed by Random Copolypeptides
Authors: Lenders Jos J. M. , Zope Harshal R. , Yamagishi Ayana , Bomans Paul H. H. , Arakaki Atsushi , Kros Alexander , de With Gijsbertus , Sommerdijk Nico A. J. M.
Published: December 2014

Control over magnetite (Fe3O4) formation is difficult to achieve in synthetic systems without using non‐aqueous media and high temperatures. In contrast, Nature employs often intrinsically disordered proteins to tightly tailor the size, shape, purity, and organization of the nanocrystals to optimize their magnetic properties. Inspired by such “flexible polyelectrolytes,” here random copolypeptides having different amino acid compositions are used as control agents in the bioinspired coprecipitation of magnetite through a ferrihydrite precursor, following a recently developed mineralization protocol. Importantly, the copolypeptide library is designed such that the amino acid composition can be optimized to simultaneously direct the size of the nanoparticles as well as their dispersibility in aqueous media in a one‐pot manner. Acidic amino acids are demonstrated to regulate the crystal size by delaying nucleation and reducing growth. Their relative content thus can be balanced to tune between the superparamagnetic and ferrimagnetic regimes, and high contents of negatively charged amino acids result in colloidal stabilization of superparamagnetic nanoparticles at high pH. Conversely, with positively charged lysine‐rich copolypeptides ferrimagnetic crystals are obtained which are stabilized at neutral pH and self‐organize in chains, as visualized by cryo‐transmission electron microscopy. Altogether, the presented findings give important insights for the future development of additive‐mediated nanomaterial syntheses.
DNA‐Schalter: Grundlagen und Anwendungen
Authors: Wang Fuan , Liu Xiaoqing , Willner Itamar
Published: December 2014

Die Basensequenz der Nukleinsäuren verschlüsselt strukturelle und funktionelle Eigenschaften in einem Biopolymer. Strukturelle Informationen beinhalten die Bildung von Duplexen, G‐Quadruplexen, i‐Motiven und kooperativ stabilisierten Anordnungen. Funktionelle Informationen betreffen z. B. den Prozess der Strangverdrängung, Erkennungseigenschaften von Aptameren und die katalytische Funktion von DNAzymen. Dieser Aufsatz befasst sich mit der Implementierung der in Nukleinsäuren kodierten Informationen zur Entwicklung von DNA‐Schaltern. Ein DNA‐Schalter ist eine supramolekulare Nukleinsäureanordnung, die in Gegenwart geeigneter Auslöser und Gegenauslöser wie pH, Metallionen/Liganden, photonischen und elektrischen Stimuli zyklische, schaltbare Übergänge zwischen zwei Zuständen eingeht. Anwendungen von schaltbaren DNA‐Systemen umfassen maßgeschneiderte DNA‐Hydrogele für die kontrollierte Wirkstofffreisetzung und die Aktivierung schaltbarer Enzymkaskaden.
Durch Schwarzkörperstrahlung angetriebene chemische Reaktivität auf Metallclustern in der Gasphase
Authors: Parry Imogen S. , Kartouzian Aras , Hamilton Suzanne M. , Balaj O. Petru , Beyer Martin K. , Mackenzie Stuart R.
Published: December 2014

Chemische Reaktionen in Rhn(N2O)m+‐Komplexen in der Gasphase wurden beobachtet, die durch Absorption von Schwarzkörperstrahlung angetrieben werden. Die Experimente wurden unter stoßfreien Bedingungen in einem Fourier‐Transformations‐Ionenzyklotronresonanz(FT‐ICR)‐Massenspektrometer durchgeführt. Die Absorption von Strahlung des mittleren Infrarotbereichs durch die in molekularer Form gebundenen N2O‐Einheiten ermöglicht einem kleinen Anteil der Clusterverteilung, N2O zu zersetzen. Dabei entstehen Clusteroxide, und molekularer Stickstoff wird freigesetzt. Die Zersetzung von N2O konkurriert mit der Desorption der Moleküle. Die Verzweigungsverhältnisse der beiden Prozesse zeigen deutliche Größeneffekte, die Unterschiede in den relativen Barrieren widerspiegeln. Die Geschwindigkeitskonstante des Zerfalls nimmt annähernd linear mit der Anzahl der Infrarotchromophore zu. Die experimentellen Ergebnisse werden mithilfe von berechneten Infrarotabsorptionsraten interpretiert.
Verschiedene Reaktivitäten von Iminoboranen gegenüber Carbenen: BN‐Isostere von Carben‐Alkin‐Addukten
Authors: Braunschweig Holger , Ewing William C. , Geetharani K. , Schäfer Marius
Published: December 2014

Die ersten Addukte von Iminoboranen mit cyclischen Alkyl(amino)carbenen (CAACs) oder N‐heterocyclischen Carbenen (NHCs) wurden bei tiefer Temperatur (−45 °C) synthetisiert und isoliert. Mit kurzen BN‐Bindungen und planaren Boratomen gleicht die Struktur dieser Addukte derjenigen isoelektronischer Imine. Bei der Reaktion von Di‐tert‐butyliminoboran mit 1,3‐Bis(isopropyl)imidazol‐2‐yliden (IPr) lagerte sich das anfänglich kurz gebildete Lewis‐Säure‐Base‐Addukt schnell zu einem Carben mit einem Aminoboransubstituenten in 4‐Position um. Erwärmen des Iminoboran‐CAAC‐Adduktes auf Raumtemperatur ergab unter intramolekularem Ringschluss ein bicyclisches 1,2‐Azaborolidin.
Preparation and characterization of braided tube reinforced polyacrylonitrile hollow fiber membranes
Authors: Quan Quan , Xiao Changfa , Liu Hailiang , Huang Qinglin , Zhao Wei , Hu Xiaoyu , Huan Guolan
Published: December 2014

Polyacrylonitrile (PAN) and polyester (PET) braided hollow tube that used as a special reinforcement are braided from their filaments via two‐dimensional weaving techniques. PAN braided tube reinforced homogeneous PAN hollow fiber membranes and PET braided tube reinforced heterogeneous PAN hollow fiber membranes are prepared by concentric circles squeezed‐coated spinning method. As for PAN hollow fiber membrane, the effects of PAN concentration on the performance of the prepared hollow fiber membranes are investigated in terms of pure water flux, protein rejection, mechanical strength, and morphology observations by a scanning electron microscope (SEM). The interfacial bonding state of the braided tube reinforced PAN hollow fiber membranes is studied by constant speed stretching method. Results show that the breaking strength of two‐dimensional braided tube reinforced PAN hollow fiber membranes is higher than 80 MPa. The structure of separation surface is similar to the structure of an asymmetric membrane. With the increase of polymer concentration, the membrane flux decreases while the retention rate of BSA increase. The membrane porosity and maximum pore size have the same decreasing tendency as the increase of PAN concentration. The results also show that the interfacial bonding state of the PAN two‐dimensional braided tube reinforced homogeneous PAN hollow fiber membranes is better than that of the PET two‐dimensional braided tube reinforced heterogeneous PAN hollow fiber membranes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41795.
Open and continuous fermentation: Products, conditions and bioprocess economy
Authors: Li Teng , Chen Xiang‐bin , Chen Jin‐chun , Wu Qiong , Chen Guo‐Qiang
Published: December 2014

Microbial fermentation is the key to industrial biotechnology. Most fermentation processes are sensitive to microbial contamination and require an energy intensive sterilization process. The majority of microbial fermentations can only be conducted over a short period of time in a batch or fed‐batch culture, further increasing energy consumption and process complexity, and these factors contribute to the high costs of bio‐products. In an effort to make bio‐products more economically competitive, increased attention has been paid to developing open (unsterile) and continuous processes. If well conducted, continuous fermentation processes will lead to the reduced cost of industrial bio‐products. To achieve cost‐efficient open and continuous fermentations, the feeding of raw materials and the removal of products must be conducted in a continuous manner without the risk of contamination, even under ‘open’ conditions. Factors such as the stability of the biological system as a whole during long cultivations, as well as the yield and productivity of the process, are also important. Microorganisms that grow under extreme conditions such as high or low pH, high osmotic pressure, and high or low temperature, as well as under conditions of mixed culturing, cell immobilization, and solid state cultivation, are of interest for developing open and continuous fermentation processes.
Experimental and Theoretical Studies on the Rearrangement of 2‐Oxoazepane α,α‐Amino Acids into 2′‐Oxopiperidine β2,3,3‐Amino Acids: An Example of Intramolecular Catalysis
Authors: Núñez‐Villanueva Diego , Bonache M. Ángeles , Lozano Laura , Infantes Lourdes , Elguero José , Alkorta Ibon , García‐López M. Teresa , González‐Muñiz Rosario , Martín‐Martínez Mercedes
Published: December 2014

Enantiopure β‐amino acids represent interesting scaffolds for peptidomimetics, foldamers and bioactive compounds. However, the synthesis of highly substituted analogues is still a major challenge. Herein, we describe the spontaneous rearrangement of 4‐carboxy‐2‐oxoazepane α,α‐amino acids to lead to 2′‐oxopiperidine‐containing β2,3,3‐amino acids, upon basic or acid hydrolysis of the 2‐oxoazepane α,α‐amino acid ester. Under acidic conditions, a totally stereoselective synthetic route has been developed. The reordering process involved the spontaneous breakdown of an amide bond, which typically requires strong conditions, and the formation of a new bond leading to the six‐membered heterocycle. A quantum mechanical study was carried out to obtain insight into the remarkable ease of this rearrangement, which occurs at room temperature, either in solution or upon storage of the 4‐carboxylic acid substituted 2‐oxoazepane derivatives. This theoretical study suggests that the rearrangement process occurs through a concerted mechanism, in which the energy of the transition states can be lowered by the participation of a catalytic water molecule. Interestingly, it also suggested a role for the carboxylic acid at position 4 of the 2‐oxoazepane ring, which facilitates this rearrangement, participating directly in the intramolecular catalysis.
Limitation of using silver ion solid‐phase extraction for animal lipids with a low trans content
Authors: Belaunzaran Xabier , Bravo‐Lamas Leire , Kramer John K. G. , Aldai Noelia
Published: December 2014

Silver ion solid‐phase extraction (Ag+‐SPE) was reported to provide effective separations compared to other Ag+ techniques but at a fraction of cost and time. Ag+‐SPE cartridges resolved fatty acid methyl esters (FAMEs) with different number and/or geometric configuration of double bonds. Here we attempted to determine the trans fatty acids (FA) contained in a low total trans FA sample, horse lipids; lamb was used as a control having a markedly higher total trans content. Gas chromatographic assessment of the fractions showed a good separation of the cis and trans monounsaturated FA (MUFA) fractions, but the relative high content of contaminants that coeluted with these FA impaired the identification of the latter in horse lipids. In lamb trans MUFA isomers could be identified since their abundance relative to impurities was greater. Several attempts were made to remove the contaminants from the SPE cartridges including an extensive prewash with acetone and hexane, a prewash with solvents that would elute the cis MUFA fraction, and a complete prewash of all solvents used in the fractionation, hexane, acetone, and acetonitrile. The prewash using all elution solvents removed most contaminants but subsequently impaired the separation of trans and cis MUFA fractions. The same samples were subjected to Ag+‐HPLC fractionation that showed no impurities demonstrating that they were derived from the Ag+‐SPE separation. The trans MUFA fraction collected from Ag+‐HPLC allowed for the identification of the trans 16:1 and 18:1 FA in horse lipids and is recommended for samples with low trans levels.

Practical applications: The commercially available silver ion solid‐phase extraction (Ag+‐SPE) cartridges contain appreciable amounts of contaminants that can interfere with the subsequent GC‐FID elution of low levels of trans fatty acid methyl esters (FAMEs), especially when contaminants are leaked by the SPE tube in quantities comparable to the trans MUFA content. The contaminants could not be quantitatively removed by prewashing the cartridges with acetone and hexane. Acetonitrile removed most contaminants but altered the Ag+‐SPE tube ability to resolve the trans and cis MUFA fractions. Ag+‐HPLC fractionation is recommended for isolation of low levels of trans MUFA, since the washing and conditioning of the chromatographic column can be extended as needed.

Ag+‐SPE cartridges are used to separate FAMEs based on number and geometric configuration of double bonds to aid in the identification of complex GC separations.
Empirical Bayesian Density Forecasting in Iowa and Shrinkage for the Monte Carlo Era
Authors: Lewis Kurt F. , Whiteman Charles H.
Published: December 2014

The track record of a 20‐year history of density forecasts of state tax revenue in Iowa is studied, and potential improvements sought through a search for better‐performing ‘priors’ similar to that conducted three decades ago for point forecasts by Doan, Litterman and Sims (Econometric Reviews, 1984). Comparisons of the point and density forecasts produced under the flat prior are made to those produced by the traditional (mixed estimation) ‘Bayesian VAR’ methods of Doan, Litterman and Sims, as well as to fully Bayesian ‘Minnesota Prior’ forecasts. The actual record and, to a somewhat lesser extent, the record of the alternative procedures studied in pseudo‐real‐time forecasting experiments, share a characteristic: subsequently realized revenues are in the lower tails of the predicted distributions ‘too often’. An alternative empirically based prior is found by working directly on the probability distribution for the vector autoregression parameters—the goal being to discover a better‐performing entropically tilted prior that minimizes out‐of‐sample mean squared error subject to a Kullback–Leibler divergence constraint that the new prior not differ ‘too much’ from the original. We also study the closely related topic of robust prediction appropriate for situations of ambiguity. Robust ‘priors’ are competitive in out‐of‐sample forecasting; despite the freedom afforded the entropically tilted prior, it does not perform better than the simple alternatives. Copyright © 2014 John Wiley & Sons, Ltd.
Electrospray MS and MALDI imaging show that non‐specific lipid‐transfer proteins (LTPs) in tomato are present as several isoforms and are concentrated in seeds
Authors: Bencivenni Mariangela , Faccini Andrea , Zecchi Riccardo , Boscaro Francesca , Moneti Gloriano , Dossena Arnaldo , Sforza Stefano
Published: December 2014

Non‐specific lipid‐transfer proteins (nsLTPs) are major human allergens in many plant species, albeit their role in plant biochemistry is still undefined. They are found in many plant species, either as one or several isoforms according to the species, and usually they are found to concentrate in the outer part of the fruits. In this work, the characterization of tomato nsLTP isoforms was performed on the three main fractions of Piccadilly tomato fruit (peel, pulp and seeds) by using ultracentrifuge devices with molecular cut‐off able to retain proteins with molecular weight typical of plant LTPs. The isolated proteins were further analysed by LC‐MS, in order to investigate the occurrence and the localization of tomato LTP isoforms. The chromatographic retention times, the molecular masses, the presence of eight cysteine residues in their tertiary structures and the sequence information obtained by MS, although not complete yet, allowed us to identify four different LTP isoforms, not yet reported in the literature, which were found to be concentrated in the seed fractions. None of the molecular masses of these potential LTPs was already present in the UniProtKB/SwissProt database. MALDI imaging experiments confirmed their presence and main localization in seeds, although the actual data hinted at their presence around seeds, rather than exactly in them. These data hint to a complicated scenario concerning LTP proteins in tomato. Copyright © 2014 John Wiley & Sons, Ltd.
Structure elucidation of phototransformation products of unapproved analogs of the erectile dysfunction drug sildenafil in artificial freshwater with UPLC‐Q Exactive‐MS
Authors: Aceña Jaume , Pérez Sandra , Gardinali Piero , Abad José Luis , Eichhorn Peter , Heuett Nubia , Barceló Damià
Published: December 2014

In this study, four unapproved analogues of Sildenafil (SDF) were photodegraded under synthetic sunlight in artificial freshwater. Homosildenafil (H‐SDF), hydroxyhomo‐sildenafil (HH‐SDF), norneosildenafil (NR‐SDF) and thiosildenafil (T‐SDF) were selected because they are frequently detected as adulterants in natural herbal products. Using UPLC‐Orbitrap (Q Exactive)‐MS, six photoproducts common to H‐SDF, HH‐SDF and T‐SDF and nine unique transformation products of different molecular weights were identified based on their high‐resolution (+)ESI product ion spectra. Mass spectral analysis of deuterated H‐SDF, labeled on the N‐ethyl group, allowed to gain mechanistic insight into the fragmentation pathway of the substituted piperazine ring and to support the postulated photoproduct structures. The mass spectral fragmentation confirmed the stepwise destruction of the piperazine ring eventually producing a sulfonic acid derivative (C17H20N4O5S: 392.1151 Da). In contrast, the photodegradation of NR‐SDF, which lacks a piperazine ring in its structure, formed only two prominent photoproducts originating from N,N‐dealkylation of the sulfonamide followed by hydrolysis. The current work constitutes the first study on the photodegradation of analogs of erectile dysfunction drugs and the first detection of two transformation products (m/z 449 and 489) in environmental samples. Copyright © 2014 John Wiley & Sons, Ltd.
Safety and efficacy of multiuse botulinum toxin vials for intralaryngeal injection
Authors: Barrow Emily M. , Rosen Clark A. , Hapner Edie R. , Smith Sarah , Hatcher Jeanne L. , Simpson Blake , Johns Michael M.
Published: December 2014

Objectives/Hypothesis

Centers for Disease Control and Prevention guidelines maintain that single‐use vials cannot be used for multiple patients. Botox product labeling states that the reconstituted toxin should be used within 4 hours on a single patient based on concerns of reduced potency, contamination, and consequent infections. The purpose of this study was to determine the safety and efficacy of using single‐use vials in a multidose fashion.

Study Design

Prospective study and cohort chart review.

Methods

A multi‐institutional three‐part study was performed between May 2013 and October 2013: 1) a summation of subjects' recall of their past experiences (symptoms/response) with previous multidose Botox injections, 2) a prospective study of intralaryngeal injections, and 3) a chart review of injection responses in a subset of the cohort.

Results

Seven hundred forty‐three subjects receiving 6,216 injections demonstrated zero infection‐related complications on retrospective chart review. One hundred seventy‐nine subjects recalled 24.0% overall adverse events, 10.6% redness, 7.3% pain and swelling at the injection site, and 0% fever. One hundred seventy‐four subjects prospectively reported 12.6% overall adverse events. The self‐reported efficacy rate of Botox injection was 96.6%.

Conclusions

The low rates of adverse events following the use of Botox in a multipatient fashion are consistent with other percutaneous injections. No evidence of infection was found with multidose Botox use. Given the low incidence of side effects and high success rate, Botox can be used both safely and effectively in a multipatient fashion.

Level of Evidence

4 Laryngoscope, 125:1149–1154, 2015
Radiation‐associated malignancies of the ear canal and temporal bone
Authors: Lambert Elton M. , Garden Adam S. , DeMonte Franco , Roberts Dianna B. , Gidley Paul W.
Published: December 2014

Objectives/Hypothesis

To examine our experience with surgically treated radiation‐associated malignancy (RAM) of the temporal bone.

Study Design

Retrospective chart review.

Methods

Thirteen patients treated surgically for temporal‐bone RAM during 1999 to 2012 were identified. Demographics, symptoms at presentation with RAM, interval between initial radiotherapy and diagnosis of RAM, pathologic features of RAM, treatment, and recurrence and survival were obtained from medical records.

Results

Ten patients had squamous cell carcinoma; three had sarcoma. The mean period between completion of radiotherapy and diagnosis of RAM was 13.38 years (range, 4.5–33.3 years). Three‐year overall and disease‐free survival rates were 59.8% and 42.3%, respectively. Seven patients (54%) had RAM limited to the external auditory canal (LEAC); six had RAM extending beyond it (EEAC). The mean age was 66.5 years for LEAC patients versus 41.1 years for EEAC patients (P = .0161). Compared to patients with EEAC disease, patients with LEAC disease were more likely to have negative margins (100% vs. 33%; P = .021) and less likely to have postoperative adjuvant therapy (0% vs. 67%; P = .0209). The 3‐year disease‐specific survival was significantly better for patients with LEAC disease versus EEAC (log rank P = .023).

Conclusions

To our knowledge, this is the largest reported series of surgically treated RAM of the ear canal or temporal bone. This study highlights the need for vigilance for RAM in patients treated with head and neck radiation.

Level of Evidence

4. Laryngoscope, 125:1198–1204, 2015
Assessment of ototoxicity of intratympanic administration of Auralgan in a chinchilla animal model
Authors: Mujica‐Mota Mario A. , Bezdjian Aren , Salehi Pezhman , Schermbrucker Jonah , Daniel Sam J.
Published: December 2014

Objectives/Hypothesis

Auralgan (benzocaine and antipyrine) is an over‐the‐counter otic drug commonly used for otalgia. Nevertheless, there is limited evidence about the effects of the drug on hearing function and cochlear morphology in the presence of a tympanic membrane perforation. The aim of the present study was to assess the cytotoxicity of Auralgan using cultured auditory cells (HEI‐OC1) and to examine its effects on hearing function and cochlear morphology after intratympanic administration in a chinchilla model.

Study Design

Animal experiment.

Methods

Cell viability and DNA labeling assays were conducted to investigate the cytotoxic effect of the drug on cultured auditory cells (HEI‐OC1). To examine the possible drug ototoxic effect in vivo, chinchillas received intratympanic injection of Auralgan in one ear, whereas the contralateral control ear received saline. Outcome measures included auditory brainstem response and postmortem cochlear morphology.

Results

A dose‐dependent toxic effect of Auralgan was noted on cultured cells. Animal experiments showed an inflammatory reaction in the experimental ears and facial paralysis in 80% of the animals on the side receiving transtympanic injection of Auralgan (P < .05). Auditory brainstem response testing demonstrated a 30‐ to 50‐dB hearing threshold shift across all frequencies tested (P < .05). Control ears showed no inflammation or significant threshold shift. Microscopy showed damage to the hair cells and stria vascularis with bleeding in the perilymphatic space in the experimental ears and damage to the hair cells.

Conclusions

Auralgan was cytotoxic to cultured auditory cells. It promoted an inflammatory reaction and seemed to be ototoxic when given via transtympanic injection in an animal model.

Level of Evidence

NA Laryngoscope, 125:1444–1448, 2015
Non‐Covalent Photo‐Patterning of Gelatin Matrices Using Caged Collagen Mimetic Peptides
Authors: Li Yang , San Boi Hoa , Kessler Julian L. , Kim Jin Hwan , Xu Qingguo , Hanes Justin , Yu Seungju Michael
Published: December 2014

To address the downside of conventional photo‐patterning which can alter the chemical composition of protein scaffolds, we developed a non‐covalent photo‐patterning strategy for gelatin (denatured collagen) hydrogels that utilizes UV activated triple helical hybridization of caged collagen mimetic peptide (caged CMP). Here we present 2D and 3D photo‐patterning of gelatin hydrogels enabled by the caged CMP derivatives, as well as creation of concentration gradients of CMPs. CMP's specificity for binding to gelatin allows patterning of almost any synthetic or natural gelatin‐containing matrix, such as gelatin‐methacrylate hydrogels and corneal tissues. This is a radically new tool for immobilizing drugs to natural tissues and for functionalizing scaffolds for complex tissue formation.
Fast Synthesis of High‐Molecular‐Weight Polyglycolide Using Diphenyl Bismuth Bromide as Catalyst
Authors: Lu Yiyang , Schmidt Christian , Beuermann Sabine
Published: December 2014

Biodegradable polymers are frequently obtained from ring‐opening polymerizations (ROPs). Applications in the biomedical sector require medical‐grade materials free of any toxic residues, as well as polymers with well‐defined properties. Thus, the selection of nontoxic catalysts for ROP, which allow for well‐controlled molecular weights, is very important. In this contribution, ROPs of diglycolide are reported by using diphenyl bismuth bromide as catalyst. The reactions are carried out in bulk at temperatures ranging from 130 to 150 °C. The number‐average molecular weights are in the range of 20–250 kg mol−1 depending on the reaction temperature and time, as well as the catalyst concentration. The reaction times required to yield diglycolide conversions exceeding 95% are in the range of minutes. The thermal properties such as melting and crystallization temperatures are independent of polymer molecular weight.

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Shape‐Memory Hydrogels with Crystallizable Oligotetrahydrofuran Side Chains
Authors: Balk Maria , Behl Marc , Nöchel Ulrich , Lendlein Andreas
Published: December 2014

Stimuli‐sensitive materials, such as shape‐memory polymers (SMP) have attracted tremendous interest in the field of biomedical applications and Regenerative Therapies. In case of implants intended for soft tissue, adequate elastic properties can be mimicked by water swollen hydrophilic polymer networks (i.e. hydrogels) and can be equipped with a shape‐memory capability. Shape‐memory hydrogels (SMHs) having body compatible transition temperatures (Ttrans) have not been reported so far. Here we explored, whether SMHs with Ttrans ≤ 37 °C could be created consisting of the hydrophilic poly(N‐vinyl pyrrolidone) segment, the crosslinker oligo(ethylene glycol) dimethacrylate (OEGDMA, Mn = 370 g · mol−1), and grafted crystallizable oligotetrahydrofuran (OTHF, Mn = 7.100 g · mol−1, Tm = 31 °C) segments as switching domains. As function of the OTHF content (30–75 wt%), the hydrogels had a degree of swelling between 450 and 3200%, a Ttrans about 26 °C, and soft mechanical properties in the kPa range. Therefore, these SMHs might be interesting biomaterial candidates e.g. as smart implants.
Long‐term corrosion behaviour of EN AW‐6060‐T6 in an aluminium/carbon‐fibre reinforced polymer self‐piercing rivet joint
Authors: Mandel M. , Krüger L.
Published: December 2014

In this study, the corrosion behaviour of a self‐piercing rivet joint which consists of a sheet of the aluminium alloy EN AW‐6060‐T6 and a carbon‐fibre reinforced polymer laminate was investigated by multiple corrosion cycles, according to the standard VDA 621‐415. Due to the electrochemically quite different corrosion behaviour of the used materials the aluminium alloy is attacked by pitting corrosion close to and below the overlap of the joint. To investigate the amount of the corrosion attack the aluminium alloy was analysed by white‐light interferometry at the most attacked region in the joint after each corrosion cycle. Based on the results of the topographical scans the pit volumes were calculated in an area of 2 × 5 mm2. The plot of the pit volume versus the corrosion cycle number revealed a sigmoidal correlation that was adequately described by the Boltzmann function. Furthermore, due to the s‐shaped pit volume – cycle number correlation three stages of pitting corrosion were identified.
Applications of aluminium hybrid foam sandwiches in battery housings for electric vehicles
Authors: Baumeister J. , Weise J. , Hirtz E. , Höhne K. , Hohe J.
Published: December 2014

Lightweight design is of special importance for purely electrically driven vehicles in order to improve driving range and market acceptance. In the project “SmartBatt” – funded by the EC under the 7th Framework Programme – a 20 kWh battery pack was developed which exhibits a 10–15% weight reduction as compared to the State of the Art. Besides an improved integration of the battery pack into the body‐in‐white a new sandwich material concept for the battery housing was used to accomplish this. Core of the innovative sandwich technology is to place polymer‐coated aluminium foam granules between pre‐moulded aluminium face sheets. Dedicated subsequent foaming of the polymer will result in a sandwich structure whose core layer consists of aluminium foam spheres embedded in a matrix of polymer foam. This approach allows excellent process control and the production of components with targeted local sandwich design. The mechanical properties of AlSi10‐Epoxy hybrid foams were determined using quasi‐static and dynamic compression tests and compared to the behaviour of epoxy‐mono‐foams.
Gliding Arc Plasma Synthesis of Visible‐Light Active C‐Doped Titania Photocatalysts
Authors: Liu Shi‐Xin , Liu Jing‐Lin , Li Xiao‐Song , Zhu Xiaobing , Zhu Ai‐Min
Published: December 2014

Gliding arc plasma is explored to synthesize C‐doped TiO2 photocatalysts via tuning the ratio of O2 to titanium tetraisopropoxide (TTIP) for the first time. XRD and HRTEM characterizations confirm that the samples synthesized at O2/TTIP ≥ 18 are highly crystalline. When the O2/TTIP ratio ranges from 18 to 36, the as‐synthesized samples with ~70% of the weight fraction of anatase, 40–50 m2 g−1 of specific surface area and ~2.7 eV of band energy gap, do show a greatly enhanced visible‐light absorption and high activity for methylene blue (MB) degradation under visible‐light irradiation (λ > 420 nm). The gray sample synthesized at O2/TTIP = 27 has the largest relative content of Ti3+ and oxygen vacancy (□) (Ti3+/□/Ti = 0.7/0.35/1) and exhibits the highest visible‐light activity.
Varenicline enhances dopamine release facilitation more than nicotine after long‐term nicotine treatment and withdrawal
Authors: Perez Xiomara A. , Khroyan Taline V. , McIntosh J. Michael , Quik Maryka
Published: December 2014

An important factor contributing to the high relapse rates among smokers is nicotine withdrawal symptoms. Multiple studies suggest that decreased dopamine release in nucleus accumbens plays a key role in withdrawal. However, recent reports showed that long‐term nicotine exposure itself also decreases accumbal dopamine release, suggesting that additional mechanisms are involved in withdrawal. Here, we used real‐time cyclic voltammetry in brain slices containing the nucleus accumbens to further elucidate the changes in dopamine release linked to nicotine withdrawal. Rats received vehicle or nicotine via the drinking water for 2–3 months. Studies assessing the expression of somatic signs in vehicle‐treated, nicotine‐treated, and 24‐h nicotine withdrawn rats showed that nicotine withdrawal led to a significant increase in somatic signs. Subsequent voltammetry studies showed that long‐term nicotine decreased single‐pulse‐stimulated dopamine release via an interaction at α6β2* receptors. Nicotine withdrawal led to a partial recovery in α6β2* receptor‐mediated release. In addition, long‐term nicotine treatment alone increased dopamine release paired‐pulse ratios and this was partially reversed with nicotine removal. We then evaluated the effect of bath‐applied nicotine and varenicline on dopamine release. Nicotine and varenicline both decreased single‐pulse‐stimulated release in vehicle‐treated, nicotine‐treated, and nicotine withdrawn rats. However, bath‐applied varenicline increased paired‐pulse ratios to a greater extent than nicotine during long‐term nicotine treatment and after its withdrawal. Altogether these data suggest that nicotine withdrawal is associated with a partial restoration of dopamine release measures to control levels and that varenicline's differential modulation of dopamine release may contribute to its mechanism of action.
Active surveillance of visual impairment due to adverse drug reactions: findings from a national study in the United Kingdom
Authors: Cumberland Phillippa M. , Russell‐Eggitt Isabelle , Rahi Jugnoo S.
Published: December 2014

As visual impairment (VI) due to adverse drug reactions (ADR) is rare in adults and children, there is an incomplete evidence base to inform guidance for screening and for counseling patients on the potential risks of medications. We report on suspected drugs and the eye conditions found in a national study of incidence of diagnosis of visual impairment due to suspected ADR. Case ascertainment was via the British Ophthalmological Surveillance Unit (BOSU), between March 2010 and February 2012, with follow‐up after 6 months. Case definition: any child or adult with bilateral or unilateral visual impairment due to a suspected ADR, using distance acuity worse than Snellen 6/18 (logMAR 0.48) in the better eye (bilateral) or affected eye (unilateral). Anonymized patient information on potential cases was provided by managing ophthalmologists, comprising visual status before and after suspected ADR, ophthalmic condition attributable to the ADR, preexisting eye disease and prescribed medications at the time of the ADR. Permanency and causality of the visual impairment were confirmed by the managing clinician, after 6 months, using the WHO Uppsala Monitoring Committee criteria. Over 2 years, 36 eligible cases were reported of whom 23 had permanent VI. While most cases were due to drugs known to have adverse side‐effects, some were unanticipated sporadic cases. Visual impairment due to ADRs is rare. However, with for example, increasing polypharmacy in the elderly, monitoring of ocular ADRs, although challenging, is necessary.
Trauma‐exposed Firefighters: Relationships among Posttraumatic Growth, Posttraumatic Stress, Resource Availability, Coping and Critical Incident Stress Debriefing Experience
Authors: Sattler David N. , Boyd Bill , Kirsch Julie
Published: December 2014

This project examines protective factors associated with resilience/posttraumatic growth and risk factors associated with posttraumatic stress among firefighters exposed to critical incidents. The participants were 286 (257 men and 29 women) volunteer and paid firefighters in Whatcom County, Washington. Participants completed an anonymous survey asking about demographics, critical incident exposure, posttraumatic stress symptoms, posttraumatic growth, resource availability, coping, occupational stress and critical incident stress debriefing experience. Most participants had significant critical incident exposure, and about half had attended critical incident stress debriefing sessions. Posttraumatic growth was associated with being female, critical incident exposure, critical incident stress debriefing attendance, posttraumatic stress symptoms (negative association), occupational support, occupation satisfaction, occupational effort, problem‐focused coping, emotion‐focused coping and personal characteristic resources. Posttraumatic stress symptoms were positively associated with years of firefighting, burnout, occupational effort and disengagement coping and negatively associated with critical incident stress debriefing attendance, posttraumatic growth, social support, internal locus of control, personal characteristic resources, energy resources and condition resources. The findings support conservation of resources stress theory and show that the maintenance and acquisition of resources can offset losses and facilitate resilience/posttraumatic growth. Implications of the findings for enhancing firefighter resources, facilitating resilience and minimizing occupational stressors are discussed. Copyright © 2014 John Wiley & Sons, Ltd.
The Development of a Three Part Model of Psychological Resilience
Authors: de Terte Ian , Stephens Christine , Huddleston Lynne
Published: December 2014

Psychological resilience has been defined as the ability of an individual to recover from a traumatic event or to remain psychologically robust when faced with an adverse event. This study investigated a sample of 176 police officers who were surveyed at commencement of their training in 1998/1999 (Time 1), 12 months later (Time 2), and at the end of 2009 (Time 3). A multidimensional model of psychological resilience (including environment, thoughts, feelings, behaviours, and physical activities) was evaluated in terms of the pathogenic outcomes of posttraumatic stress, psychological distress, and physical health at the three time points. A three part model of psychological resilience (environment, physical behaviours, and cognitions) was used to demonstrate that social support, adaptive health practices, adaptive coping, and optimism were effective when police officers were faced with adversity. The model provides initial understandings of the multidimensional nature of psychological resilience which requires further evaluation. Copyright © 2014 John Wiley & Sons, Ltd.
Constellation constrained multiuser multiple‐input multiple‐output for high capacity and error performance over correlated fading channels
Authors: Al‐Hussaibi Walid A. , Ali Falah H.
Published: December 2014

Channels' correlation has direct impact to degrade the capacity and reliability of multiple‐input multiple‐output (MIMO) systems considerably. In this paper, new signal constellation designs are investigated to mitigate fading correlation and maximize the capacity and error performance of multiuser MIMO (MU‐MIMO) over correlated channels, which is a major research challenge. Two methods are studied in a novel constellation constrained MU‐MIMO approach, namely, unequal power allocation and rotated constellation. Based on principles of maximizing the minimum Euclidean distance (dmin) of composite received signals, users' data can be recovered using maximum likelihood joint detection irrespective of correlation values. Compared with the identical constellation scenario in conventional MU‐MIMO, it is shown that constellation rearrangement of transmitted signals has direct impact to resolve the detection ambiguity when the channel difference is not sufficient, particularly in moderate to high correlations. Extensive analysis and simulation results demonstrate the superiority of proposed technique to capture most of the promised gains of multiantenna systems and application for future wireless communications. Copyright © 2014 John Wiley & Sons, Ltd.
Slit molecules prevent entrance of trunk neural crest cells in developing gut
Authors: Zuhdi Nora , Ortega Blanca , Giovannone Dion , Ra Hannah , Reyes Michelle , Asención Viviana , McNicoll Ian , Ma Le , de Bellard Maria Elena
Published: December 2014

Neural crest cells emerge from the dorsal neural tube early in development and give rise to sensory and sympathetic ganglia, adrenal cells, teeth, melanocytes and especially enteric nervous system. Several inhibitory molecules have been shown to play important roles in neural crest migration, among them are the chemorepulsive Slit1–3. It was known that Slits chemorepellants are expressed at the entry to the gut, and thus could play a role in the differential ability of vagal but not trunk neural crest cells to invade the gut and form enteric ganglia. Especially since trunk neural crest cells express Robo receptor while vagal do not. Thus, although we know that Robo mediates migration along the dorsal pathway in neural crest cells, we do not know if it is responsible in preventing their entry into the gut. The goal of this study was to further corroborate a role for Slit molecules in keeping trunk neural crest cells away from the gut. We observed that when we silenced Robo receptor in trunk neural crest, the sympathoadrenal (somites 18–24) were capable of invading gut mesenchyme in larger proportion than more rostral counterparts. The more rostral trunk neural crest tended not to migrate beyond the ventral aorta, suggesting that there are other repulsive molecules keeping them away from the gut. Interestingly, we also found that when we silenced Robo in sacral neural crest they did not wait for the arrival of vagal crest but entered the gut and migrated rostrally, suggesting that Slit molecules are the ones responsible for keeping them waiting at the hindgut mesenchyme. These combined results confirm that Slit molecules are responsible for keeping the timeliness of colonization of the gut by neural crest cells.
Development of non‐catecholaminergic sympathetic neurons in para‐ and prevertebral ganglia of cats
Authors: Masliukov Petr M. , Emanuilov Andrey I. , Moiseev Konstantin , Nozdrachev Alexandr D. , Dobrotvorskaya Svetlana , Timmermans Jean‐Pierre
Published: December 2014

Expression of vasoactive intestinal peptide (VIP), neuronal nitric oxide synthase (nNOS), choline acetyltransferase (ChAT) and calcitonin gene‐related peptide (CGRP) in the sympathetic ganglia was investigated by immunohistochemistry in the superior cervical ganglion (SCG), stellate ganglion (SG) and celiac ganglion (CG) from cats of different ages (newborn, 10‐day‐old, 20‐day‐old, 30‐day‐old and 2‐month‐old). Non‐catecholaminergic TH‐negative VIP‐immunoreactive (IR) and nNOS‐IR sympathetic ganglionic neurons are present from the moment of birth. In all studied age groups, substantial populations of VIP‐IR (up to 9.8%) and nNOS‐IR cells (up to 8.3%) was found in the SG, with a much smaller population found in the SCG (<1%) and only few cells observed in the CG. The percentage of nNOS‐IR and VIP‐IR neurons in the CG and SCG did not significantly change during development. The proportion of nNOS‐IR and VIP‐IR neuron profiles in the SG increased in first 20 days of life from 2.3 ± 0.15% to 8.3 ± 0.56% and from 0.3 ± 0.05% to 9.2 ± 0.83%, respectively. In the SG, percentages of nNOS‐IR sympathetic neurons colocalizing VIP increased in the first 20 days of life. ChAT‐IR and CGRP‐IR neurons were not observed in the sympathetic ganglia of newborn animals and did not appear until 10 days after birth. In the SG of newborn and 10‐day‐old kittens, the majority of NOS‐IR neurons were calbindin (CB)‐IR, whereas in the SCG and CG of cats of all age groups and in the SG of 30‐day‐old and older kittens, the vast majority of NOS‐IR neurons lacked CB. We conclude that the development of various non‐catecholaminergic neurons in different sympathetic ganglia has its own time dynamics and is concluded at the end of the second month of life.
Coverage and distribution of obstetricians and gynecologists in Nigeria
Authors: Agboghoroma Chris O. , Gharoro Etedafe P.
Published: December 2014

Objective

To determine the number, regional spread, and population ratio of obstetricians and gynecologists (OB/GYNs) in Nigeria.

Methods

Data for the present descriptive study were collected between July 1, 2012, and December 31, 2013, as part of a national survey of OB/GYNs. Information was obtained about characteristics, qualifications, place of work, primary employer, subspecialty interest, and type of practice.

Results

In total, 968 OB/GYNs were identified, of whom 846 (87.4%) were male. The estimated national population in 2013 was 175 651 197, which meant that there was one OB/GYN for every 181 458 individuals. Lagos State had the highest number of OB/GYNs (179 [18.5%]), whereas Yobe State had only 2 (0.2%) and Jigawa State 1 (0.1%). The geopolitical region with the highest number of OB/GYNs was the South West (315 [32.5%]), whereas the North East had the lowest number (45 [4.6%]).

Conclusion

The number of OB/GYNs in Nigeria is inadequate in view of the population size, and coverage varies greatly in different states. Efforts to improve maternal health and reduce the maternal mortality ratio should include more investment in training, engagement, and equitable distribution of OB/GYNs in all parts of the country.
Effects of intravenous human immunoglobulin on late hyporegenerative anemia secondary to rhesus hemolytic disease of the newborn
Authors: Al-Alaiyan Saleh , Ahmad Husain Alsaid , Al-Hazzani Fahad , AlHasan Mai , Dawoud Magdy , Khadawardi Emad , Al-Midani Eyad
Published: December 2014

Background and objectives:

To determine the effects of intravenous immunoglob-ulin (IVIg) on the course of late hyporegenerative anemia and the requirement for exchange transfusions, phototherapy and top-up red blood cell transfusions due to rhesus hemolytic dis-ease of the newborn (Rh-HDN).

Patients and methods:

This is retrospective cohort study of newborns with Rh-HDN who were treated with or without IVIg. Relevant maternal and neonatal data were obtained and analyzed. All infants were followed up as outpatients for a period of 2-3 months, and during the follow ups, complete blood counts (RBCs) were performed every two weeks to diagnose late hyporegenerative anemia.

Results:

Sixty-six infants with Rh-HDN were enrolled in this study (42 in the IVIg group and 24 in the no-IVIg group). We observed no significant differences between the two groups in terms of maternal age, number of previous children affected with Rh-HDN, intrauterine transfusions, gestational age (GA), birth weight (BW), Apgar scores at the 1st or 5th minutes, exchange transfusions, or days on phototherapy. The serum bilirubin immediately after birth and the maximum serum bilirubin during the hospital course were significantly higher in the IVIG group (P = 0.0035 and P = 0.0225, respectively). Although there were no statistically significant dif-ferences, there was a trend toward the late anemia in the IVIg group being diagnosed and resolved earlier than in the no-IVIg group. Additionally, a greater proportion of the IVIg group required three or more top-up transfusions compared to the no-IVIg group, but this difference was not statistically significant.

Conclusion:

IVIg might have had an effect on the early development of late anemia and might have shortened the duration of late anemia relative to the infants who did not receive IVIg. The exchange transfusions and the days on phototherapy were not affected by IVIg.