bluuebunny/crossref_metadata_2025 huggingface dataset:
Multidecadal modulations of the low‐frequency climate variability in the wintertime North Pacific since 1950
Authors: Miyasaka Takafumi , Nakamura Hisashi , Taguchi Bunmei , Nonaka Masami
Published: April 2014

The North Pacific decadal variability (PDV) is known to manifest itself as two distinct spatial patterns. Observations since 1950 reveal that the wintertime PDV underwent notable modulations of their dominance in sea surface temperature (SST) variability and accompanying atmospheric variability. Until the 1980s, decadal SST variability was strongest along the subarctic frontal zone (SAFZ), the boundary between the warm Kuroshio and cool Oyashio waters. The SAFZ variability was highly correlated with decadal variability of the surface Aleutian Low but not simultaneously with tropical SST variability. Since the 1990s, however, this extratropical ocean‐atmosphere variability has lost its predominance, taken over by SST variability in the subtropical frontal zone. It accompanies subtropical anticyclone variability, exhibiting significant anticorrelation with tropical SST variability. These long‐term PDV modulations have remotely modulated temperature variability over Canada and Alaska. Similar PDV modulations are simulated in a centennial integration of a global climate model.
Inner belt and slot region electron lifetimes and energization rates based on AKEBONO statistics of whistler waves
Authors: Agapitov O. V. , Artemyev A. V. , Mourenas D. , Kasahara Y. , Krasnoselskikh V.
Published: April 2014

Global statistics of the amplitude distributions of hiss, lightning‐generated, and other whistler mode waves from terrestrial VLF transmitters have been obtained from the EXOS‐D (Akebono) satellite in the Earth's plasmasphere and fitted as functions of L and latitude for two geomagnetic activity ranges (Kp<3 and Kp>3). In particular, the present study focuses on the inner zone L∈[1.4,2] where reliable in situ measurements were lacking. Such statistics are critically needed for an accurate assessment of the role and relative dominance of each type of wave in the dynamics of the inner radiation belt. While VLF waves seem to propagate mainly in a ducted mode at L∼1.5–3 for Kp<3, they appear to be substantially unducted during more disturbed periods (Kp>3). Hiss waves are generally the most intense in the inner belt, and lightning‐generated and hiss wave intensities increase with geomagnetic activity. Lightning‐generated wave amplitudes generally peak within 10° of the equator in the region L<2 where magnetosonic wave amplitudes are weak for Kp<3. Based on this statistics, simplified models of each wave type are presented. Quasi‐linear pitch angle and energy diffusion rates of electrons by the full wave model are then calculated. Corresponding electron lifetimes compare well with decay rates of trapped energetic electrons obtained from Solar Anomalous and Magnetospheric Particle Explorer and other satellites at L∈[1.4,2].
Image processing of multiphase images obtained via X‐ray microtomography: A review
Authors: Schlüter Steffen , Sheppard Adrian , Brown Kendra , Wildenschild Dorthe
Published: April 2014

Easier access to X‐ray microtomography (μCT) facilities has provided much new insight from high‐resolution imaging for various problems in porous media research. Pore space analysis with respect to functional properties usually requires segmentation of the intensity data into different classes. Image segmentation is a nontrivial problem that may have a profound impact on all subsequent image analyses. This review deals with two issues that are neglected in most of the recent studies on image segmentation: (i) focus on multiclass segmentation and (ii) detailed descriptions as to why a specific method may fail together with strategies for preventing the failure by applying suitable image enhancement prior to segmentation. In this way, the presented algorithms become very robust and are less prone to operator bias. Three different test images are examined: a synthetic image with ground‐truth information, a synchrotron image of precision beads with three different fluids residing in the pore space, and a μCT image of a soil sample containing macropores, rocks, organic matter, and the soil matrix. Image blur is identified as the major cause for poor segmentation results. Other impairments of the raw data like noise, ring artifacts, and intensity variation can be removed with current image enhancement methods. Bayesian Markov random field segmentation, watershed segmentation, and converging active contours are well suited for multiclass segmentation, yet with different success to correct for partial volume effects and conserve small image features simultaneously.
Online concurrent reinforcement learning algorithm to solve two‐player zero‐sum games for partially unknown nonlinear continuous‐time systems
Authors: Yasini Sholeh , Karimpour Ali , Naghibi Sistani Mohammad‐Bagher , Modares Hamidreza
Published: April 2014

Online adaptive optimal control methods based on reinforcement learning algorithms typically need to check for the persistence of excitation condition, which is necessary to be known a priori for convergence of the algorithm. However, this condition is often infeasible to implement or monitor online. This paper proposes an online concurrent reinforcement learning algorithm (CRLA) based on neural networks (NNs) to solve the H ∞  control problem of partially unknown continuous‐time systems, in which the need for persistence of excitation condition is relaxed by using the idea of concurrent learning. First, H ∞  control problem is formulated as a two‐player zero‐sum game, and then, online CRLA is employed to obtain the approximation of the optimal value and the Nash equilibrium of the game. The proposed algorithm is implemented on actor–critic–disturbance NN approximator structure to obtain the solution of the Hamilton–Jacobi–Isaacs equation online forward in time. During the implementation of the algorithm, the control input that acts as one player attempts to make the optimal control while the other player, that is, disturbance, tries to make the worst‐case possible disturbance. Novel update laws are derived for adaptation of the critic and actor NN weights. The stability of the closed‐loop system is guaranteed using Lyapunov technique, and the convergence to the Nash solution of the game is obtained. Simulation results show the effectiveness of the proposed method. Copyright © 2014 John Wiley & Sons, Ltd.
High Throughput Screening of Dynamic Silk‐Elastin‐Like Protein Biomaterials
Authors: Wang Qin , Xia Xiaoxia , Huang Wenwen , Lin Yinan , Xu Qiaobing , Kaplan David L.
Published: April 2014

The need for dynamic, elastomeric polymeric biomaterials remains high, with few options with tunable control of mechanical properties, and environmental responses. Yet the diversity of these types of protein polymers pursued for biomaterials‐related needs remains limited. Robust high‐throughput synthesis and characterization methods will address the need to expand options for protein‐polymers for a range of applications. Here, a combinatorial library approach with high throughput screening is used to select specific examples of dynamic protein silk‐elastin‐like polypeptides (SELPs) with unique stimuli responsive features, including tensile strength and adhesion. Using this approach, 64 different SELPs with different sequences and molecular weights are selected out of over 2000 recombinant E. coli colonies. New understanding of sequence‐function relationships with this family of proteins is gained through this combinatorial‐screening approach and can provide a guide to future library designs. Further, this approach yields new families of SELPs to match specific material functions.
Novel Heterogeneous Integration Technology of III–V Layers and InGaAs FinFETs to Silicon
Authors: Dai Xing , Nguyen Binh‐Minh , Hwang Yoontae , Soci Cesare , Dayeh Shadi A.
Published: April 2014

Heterogeneous integration of III–V compound semiconductors to Si substrates is regarded as a necessary step for advancing high‐speed electronics and hybrid optoelectronic systems for data processing and communications, and is extensively being pursued by the semiconductor industry. Here, an innovative fab‐compatible, hybrid integration process of III–V materials to Si, namely InGaAs thin films to insulator‐on‐Si, is reported, and the first III–V FinFET devices on Si are demonstrated. Transfer of crystalline InGaAs layers with high quality to SiO2/Si is accomplished by the formation of a robust interfacial nickel‐silicide (NiSi) bonding interface, marking the first report for using silicides in III–V hybrid integration technology. The performance of optimally fabricated InGaAs FinFETs on insulator on Si is systematically investigated for a broad range of channel lengths and Fin perimeters with excellent switching characteristics. This demonstrates a viable approach to large‐scale hybrid integration of active III‐V devices to mainstream Si CMOS technology, enabling low‐power electronic and fully‐integrated optoelectronic applications.
Biodegradable Self‐Folding Polymer Films with Controlled Thermo‐Triggered Folding
Authors: Stroganov Vladislav , Zakharchenko Svetlana , Sperling Evgeni , Meyer Anne K. , Schmidt Oliver G. , Ionov Leonid
Published: April 2014

Self‐folding films are a unique kind of thin film. They are able to deform in response to a change in environmental conditions or internal stress and form complex 3D structures. They are very promising candidates for the design of bioscaffolds, which resemble different kinds of biological tissues. In this paper, a very simple and cheap approach for the fabrication of fully biodegradable and biocompatible self‐rolled tubes is reported. The tubes' folding can be triggered by temperature. A bilayer approach is used, where one component is active and another one is passive. The passive one can be any biocompatible, biodegradable, hydrophobic polymer. Gelatin is used as an active component: it allows the design of (i) self‐folding polymer films, which fold at room temperature (22 °C) and irreversibly unfold at 37 °C, and (ii) films, which are unfolded at room temperature (22 °C), but irreversibly fold at 37 °C. The possibilities of encapsulation of neural stem cells are also demonstrated using self‐folded tubes.
In Situ Generation of Tunable Porosity Gradients in Hydrogel‐Based Scaffolds for Microfluidic Cell Culture
Authors: Al‐Abboodi Aswan , Tjeung Ricky , Doran Pauline M. , Yeo Leslie Y. , Friend James , Yik Chan Peggy Pui
Published: April 2014

Compared with preformed anisotropic matrices, an anisotropic matrix that allows users to alter its properties and structure in situ after synthesis offers the important advantage of being able to mimic dynamic in vivo microenvironments, such as in tissues undergoing morphogenesis or in wounds undergoing tissue repair. In this study, porous gradients are generated in situ in a hydrogel comprising enzymatically crosslinked gelatin hydroxyphenylpropionic acid (GTN–HPA) conjugate and carboxylmethyl cellulose tyramine (CMC–TYR) conjugate. The GTN–HPA component acts as the backbone of the hydrogel, while CMC–TYR acts as a biocompatible sacrificial polymer. The hydrogel is then used to immobilize HT1080 human fibrosarcoma cells in a microfluidic chamber. After diffusion of a biocompatible cellulase enzyme through the hydrogel in a spatially controlled manner, selective digestion of the CMC component of the hydrogel by the cellulase gives rise to a porosity gradient in situ instead of requiring its formation during hydrogel synthesis as with other methods. The influence of this in situ tunable porosity gradient on the chemotactic response of cancer cells is subsequently studied both in the absence and presence of chemoattractant. This platform illustrates the potential of hydrogel‐based microfluidics to mimic the 3D in vivo microenvironment for tissue engineering and diagnostic applications.
A Flexible Solution to Anion Transport: Powerful Anionophores Based on a Cyclohexane Scaffold
Authors: Cooper James A. , Street Steven T. G. , Davis Anthony P.
Published: April 2014

Transmembrane anion carriers (anionophores) have potential for biological activity, including the treatment of channelopathies such as cystic fibrosis. A new family of anionophores has been synthesized, in which three thiourea groups are mounted on a cyclohexane‐based scaffold. Though conceptually related to earlier polycyclic systems, these molecules are simpler and far more accessible. Preorganization is somewhat reduced compared to earlier systems, and anion affinities are correspondingly lower. However, transport activities set new records. This surprising performance suggests a role for controlled flexibility in the design of transmembrane anion carriers.
White‐Light‐Emitting Edge‐Functionalized Graphene Quantum Dots
Authors: Sekiya Ryo , Uemura Yuichiro , Murakami Hideki , Haino Takeharu
Published: April 2014

Graphene quantum dots (GQDs) have received considerable attention for their potential applications in the development of novel optoelectronic materials. In the generation of optoelectronic devices, the development of GQDs that are regulated in terms of their size and dimensions and are unoxidized at the sp2 surfaces is desired. GQDs functionalized with bulky Fréchet’s dendritic wedges at the GQD periphery were synthesized. The single‐layered, size‐regulated structures of the dendronized GQDs were revealed by atomic force microscopy. The edge‐functionalization of the GQDs led to white‐light emission, which is an uncommon feature.
Trinuclear Pd3O2 Intermediate in Aerobic Oxidation Catalysis
Authors: Ingram Andrew J. , Solis‐Ibarra Diego , Zare Richard N. , Waymouth Robert M.
Published: April 2014

The activation of O2 is a key step in selective catalytic aerobic oxidation reactions mediated by transition metals. The bridging trinuclear palladium species, [(LPdII)3(μ3‐O)2]2+ (L=2,9‐dimethylphenanthroline), was identified during the [LPd(OAc)]2(OTf)2‐catalyzed aerobic oxidation of 1,2‐propanediol. Independent synthesis, structural characterization, and catalytic studies of the trinuclear compound show that it is a product of oxygen activation by reduced palladium species and is a competent intermediate in the catalytic aerobic oxidation of alcohols. The formation and catalytic activity of the trinuclear Pd3O2 species illuminates a multinuclear pathway for aerobic oxidation reactions catalyzed by Pd complexes.
Supramolecular Polymerization Promoted and Controlled through Self‐Sorting
Authors: Huang Zehuan , Yang Liulin , Liu Yiliu , Wang Zhiqiang , Scherman Oren A. , Zhang Xi
Published: April 2014

A new method in which supramolecular polymerization is promoted and controlled through self‐sorting is reported. The bifunctional monomer containing p‐phenylene and naphthalene moieties was prepared. Supramolecular polymerization is promoted by selective recognition between the p‐phenylene group and cucurbit[7]uril (CB[7]), and 2:1 complexation of the naphthalene groups with cucurbit[8]uril (CB[8]). The process can be controlled by tuning the CB[7] content. This development will enrich the field of supramolecular polymers with important advances towards the realization of molecular‐weight and structural control.
Magnesiacyclopentadienes as Alkaline‐Earth Metallacyclopentadienes: Facile Synthesis, Structural Characterization, and Synthetic Application
Authors: Wei Junnian , Liu Liang , Zhan Ming , Xu Ling , Zhang Wen‐Xiong , Xi Zhenfeng
Published: April 2014

Metallacyclopentadienes have attracted much attention as building blocks for synthetic chemistry as well as key intermediates in many metal‐mediated or metal‐catalyzed reactions. However, metallacyclopentadienes of the alkaline‐earth metals have not been reported, to say nothing of their structures, reaction chemistry, and synthetic applications. In this work, the first series of magnesiacyclopentadienes, spiro‐dilithio magnesiacyclopentadienes, and dimagnesiabutadiene were synthesized from 1,4‐dilithio 1,3‐butadienes. Single‐crystal X‐ray structural analysis of these magnesiacycles revealed unique structural characteristics and bonding modes. Their reaction chemistry and synthetic application were preliminarily studied and efficient access to amino cyclopentadienes was established through their reaction with thioformamides. Experimental and DFT calculations demonstrated that these magnesiacyclopentadienes could be regarded as bis(Grignard) reagents wherein the two MgC(sp2) bonds have a synergetic effect when reacting with substrates.
Pressure‐Induced Bond Rearrangement and Reversible Phase Transformation in a Metal–Organic Framework
Authors: Spencer Elinor C. , Kiran Mangalampalli S. R. N. , Li Wei , Ramamurty Upadrasta , Ross Nancy L. , Cheetham Anthony K.
Published: April 2014

Pressure‐induced phase transformations (PIPTs) occur in a wide range of materials. In general, the bonding characteristics, before and after the PIPT, remain invariant in most materials, and the bond rearrangement is usually irreversible due to the strain induced under pressure. A reversible PIPT associated with a substantial bond rearrangement has been found in a metal–organic framework material, namely [tmenH2][Er(HCOO)4]2 (tmenH22+=N,N,N′,N′‐tetramethylethylenediammonium). The transition is first‐order and is accompanied by a unit cell volume change of about 10 %. High‐pressure single‐crystal X‐ray diffraction studies reveal the complex bond rearrangement through the transition. The reversible nature of the transition is confirmed by means of independent nanoindentation measurements on single crystals.
Heterocycle Synthesis Based on Allylic Alcohol Transposition Using Traceless Trapping Groups
Authors: Xie Youwei , Floreancig Paul E.
Published: April 2014

Allylic alcohols undergo transposition reactions in the presence of Re2O7 whereby the equilibrium can be dictated by trapping one isomer with a pendent electrophile. Additional ionization can occur when the trapping group is an aldehyde or ketone, thus leading to cyclic oxocarbenium ion formation. Terminating the process through bimolecular nucleophilic addition into the intermediate provides a versatile method for the synthesis of diverse oxygen‐containing heterocycles. Understanding the relative rates of the steps in the sequence leads to the design of reactions which create multiple stereocenters with good to excellent levels of control.
Programmable Polymer‐Based Supramolecular Temperature Sensor with a Memory Function
Authors: Sambe Léna , de La Rosa Victor R. , Belal Khaled , Stoffelbach François , Lyskawa Joel , Delattre François , Bria Marc , Cooke Graeme , Hoogenboom Richard , Woisel Patrice
Published: April 2014

A new class of polymeric thermometers with a memory function is reported that is based on the supramolecular host–guest interactions of poly(N‐isopropylacrylamide) (PNIPAM) with side‐chain naphthalene guest moieties and the tetracationic macrocycle cyclobis(paraquat‐p‐phenylene) (CBPQT4+) as the host. This supramolecular thermometer exhibits a memory function for the thermal history of the solution, which arises from the large hysteresis of the thermoresponsive LCST phase transition (LCST=lower critical solution temperature). This hysteresis is based on the formation of a metastable soluble state that consists of the PNIPAM–CBPQT4+ host–guest complex. When heated above the transition temperature, the polymer collapses, and the host–guest interactions are disrupted, making the polymer more hydrophobic and less soluble in water. Aside from providing fundamental insights into the kinetic control of supramolecular assemblies, the developed thermometer with a memory function might find use in applications spanning the physical and biological sciences.
A Rapid Synthesis of 4‐Oxazolidinones: Total Synthesis of Synoxazolidinones A and B
Authors: Shymanska Nataliia V. , An Il Hwan , Pierce Joshua G.
Published: April 2014

A five‐step total synthesis of the marine natural product synoxazolidinone A was achieved through a diastereoselective imine acylation/cyclization cascade. Synoxazolidinone B and a series of analogues were also prepared to explore the potential of these 4‐oxazolidinone natural products as antimicrobial agents. These studies confirmed the importance of the chlorine substituent for antimicrobial activity and revealed simplified dichloro derivatives that are equally potent against several bacterial strains.
Altering associations of doxorubicin‐loaded alginate esters micelles in presence of β‐cyclodextrin
Authors: Zhou Qiquan , Yang Jisheng
Published: April 2014

The aim of this article was to evaluate the effects of β‐cyclodextrin (β‐CD) on doxorubicin (DOX)‐loaded alginate esters (SA‐C16) micelles (DOX/SA‐C16) in aqueous solution. DOX was physically loaded into SA‐C16 micelles by an o/w emulsion method with a substantial encapsulation efficiency (EE) level (36.12%), and DOX/SA‐C16 was distributed in size diameters of approximately 254 nm. SA‐C16 as carriers for the DOX can lead to the formation of associative networks in aqueous solutions between the hydrophobic tails of SA‐C16 and DOX, and the dried morphology of DOX/SA‐C16 aggregate was spherical shape. Addition of β‐CD to the system of DOX/SA‐C16 facilitated decoupling of these associations via inclusion complex formation between β‐CD cavities and the polymer hydrophobic tails that produced the release of DOX immediately, and the EE level was dropped to 0.08%, and at the same time the size distribution of aggregate was increased to about 413 nm, moreover, the aggregate was relatively large and becoming irregular spherical shape. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40702.
Alkaline fungal degradation of oxidized polyethylene in black liquor: Studies on the effect of lignin peroxidases and manganese peroxidases
Authors: Mukherjee Shritama , Kundu Patit P.
Published: April 2014

High‐molecular‐weight polyethylene is resistant to natural environmental degradation for its crystalline, hydrophobic structure. In this study, waste polyethylene bags are chemically oxidized at 80°C for 5 days by potassium dichromate solutions of various concentrations along with sulfuric acid. Absorbance peaks of carbonyl and carboxylate ions in the Fourier transform infrared spectroscopy spectra and formation of amorphous phase from crystalline one as indicated in X ray diffraction studies of oxidized polyethylenes indicate the formation of a polar hydrophilic and low‐molecular‐weight material after oxidation. From the scanning electron microscopy studies, it is observed that reacted polyethylene surface is disintegrated and numerous fissures are formed throughout the surface. The respective weight loss of incubated oxidized polyethylene with Phanerochaete chrysosporium (MTCC‐787) after 15 days of incubation is 70%, respectively, in black liquor–glucose–malt extract medium. As both lignin peroxidase (LiP) and manganese peroxidase (MnP) were detected in this media, further degradation of oxidized polyethylene is carried out in four different media with varying amount of N and Mn. The weight loss is observed only in media with excess nitrogen (N) and limited manganese (Mn), the condition which enhances the presence of LiP and MnP. This indicates that these enzymes are essential for degradation of lignin as well as oxidized polyethylene. UV spectroscopic studies indicate 40% decrease in the lignin concentration. This process of fungal degradation of chemically oxidized polyethylene using black liquor is very quick compared to the other related studies, leading to the simultaneous degradation of two waste materials, polyethylene and black liquor. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40738.
Nonsyndromic cleft lip with or without cleft palate: Increased burden of rare variants withinGremlin‐1, a component of the bone morphogenetic protein 4 pathway
Authors: Al Chawa Taofik , Ludwig Kerstin U. , Fier Heide , Pötzsch Bernd , Reich Rudolf H. , Schmidt Gül , Braumann Bert , Daratsianos Nikolaos , Böhmer Anne C. , Schuencke Hannah , Alblas Margrieta , Fricker Nadine , Hoffmann Per , Knapp Michael , Lange Christoph , Nöthen Markus M. , Mangold Elisabeth
Published: April 2014

Background

The genes Gremlin‐1 (GREM1) and Noggin (NOG) are components of the bone morphogenetic protein 4 pathway, which has been implicated in craniofacial development. Both genes map to recently identified susceptibility loci (chromosomal region 15q13, 17q22) for nonsyndromic cleft lip with or without cleft palate (nsCL/P). The aim of the present study was to determine whether rare variants in either gene are implicated in nsCL/P etiology.

Methods

The complete coding regions, untranslated regions, and splice sites of GREM1 and NOG were sequenced in 96 nsCL/P patients and 96 controls of Central European ethnicity. Three burden and four nonburden tests were performed. Statistically significant results were followed up in a second case‐control sample (n = 96, respectively). For rare variants observed in cases, segregation analyses were performed.

Results

In NOG, four rare sequence variants (minor allele frequency < 1%) were identified. Here, burden and nonburden analyses generated nonsignificant results. InGREM1, 33 variants were identified, 15 of which were rare. Of these, five were novel. Significantp‐values were generated in three nonburden analyses. Segregation analyses revealed incomplete penetrance for all variants investigated.

Conclusion

Our study did not provide support for NOG being the causal gene at 17q22. However, the observation of a significant excess of rare variants inGREM1supports the hypothesis that this is the causal gene at chr. 15q13. Because no single causal variant was identified, future sequencing analyses ofGREM1should involve larger samples and the investigation of regulatory elements.Birth Defects Research (Part A) 100:493–498, 2014. © 2014 Wiley Periodicals, Inc.
Development and thermodynamic evaluation of novel lipid raft stationary phase chromatography for screening potential antitumor agents
Authors: Tong Shanshan , Sun Chaonan , Cao Xia , Zheng Qianfeng , Zhang Huiyun , Firempong Caleb Kesse , Feng Yingshu , Yang Yan , Yu Jiangnan , Xu Ximing
Published: April 2014

Novel lipid raft stationary phase chromatography (LRSC), with lipid rafts that contain abundant tropomyosin‐related tyrosine kinase A receptors immobilized on the stationary phase, was developed for a high‐throughput screening of potentially active antitumor agents. Lestaurtinib was used as a model compound to determine the operational parameters of the LRSC. Of all the factors considered, the particle size of column packing, the column temperature and the flow rate were of immense importance in determining the performance of the established LRSC system. In order to profoundly comprehend the binding interaction between the model drug and the receptors on the column, thermodynamic studies were employed. The results revealed that the interaction was spontaneous and exothermic, a typical enthalpy‐driven process. Additionally, the primary forces were hydrogen bonding and van der Waals forces. In evaluating the applicability of the method, active extracts from Albizziae Cortex were screened out using the LRSC system under the optimized conditions. The bioactive components were successfully confirmed by the MTT assay. In conclusion, it could be said that the LRSC is a good model for screening potential antitumor agents because of its viability, rapid response and scalable features. Copyright © 2014 John Wiley & Sons, Ltd.
Intranasal Odorant Concentrations in Relation to Sniff Behavior
Authors: Beauchamp Jonathan , Scheibe Mandy , Hummel Thomas , Buettner Andrea
Published: April 2014

Knowledge on how odorants are transported through the nasal cavity to the olfactory epithelium is limited. One facet of this is how the sniffing behavior affects the abundance of odorants transferred to the olfactory cleft and in turn influences odor perception. A novel system that couples an online mass spectrometer with an odorant pulse delivery olfactometer was employed to characterize intranasal odorant concentrations of butane‐2,3‐dione (or butanedione, commonly known as diacetyl) at the interior naris and the olfactory cleft. Volunteers (n=12) were asked to perform different modes of sniffing in relation to the sniff intensity that were categorized as ‘normal’, ‘rapid’ and ‘forced’. The highest concentrations of butanedione at both positions in the nose were observed during normal sniffing, with the lowest concentrations correlating with periods of forced sniffs. This corresponded to the panelists' ratings that normal sniffing elicited the highest odor intensities. These feasibility assessments pave the way for more in‐depth analyses with a variety of odorants of different chemical classes at various intranasal positions, to investigate the passage and uptake of odorants within the nasal cavity.
Chemical Composition and Biological Activity of the Essential Oil of Origanum vulgare ssp. hirtum from Different Areas in the Southern Apennines (Italy)
Authors: Mancini Emilia , Camele Ippolito , Elshafie Hazem S. , De Martino Laura , Pellegrino Carlo , Grulova Daniela , De Feo Vincenzo
Published: April 2014

The chemical composition of the essential oils of Origanum vulgare ssp. hirtum, growing wild in three different localities in the Southern Apennines, was studied by GC‐FID and GC/MS analyses. In total, 103 compounds were identified. The oils were mainly composed of phenolic compounds and all oils belonged to the chemotype carvacrol/thymol. The three essential oils were evaluated for their in vitro phytotoxic activity by determining their influence on the germination and initial radicle elongation of Sinapis arvensis L., Phalaris canariensis L., Lepidium sativum L., and Raphanus sativus L. The seed germination and radicle growth were affected in various degrees. Moreover, the antifungal activity of the three essential oils was assayed against three species causing pre‐ and postharvest fruit decay (Monilinia laxa, M. fructigena, and M. fructicola). At 1000 ppm, the three oils completely inhibited fungal growth. The hemolytic activity of the oils was assayed and showed no effect on the cell membranes of bovine erythrocytes.
Progress and Challenges in Electrical Comminution by High‐Voltage Pulses
Authors: Shi Fengnian , Manlapig Emmy , Zuo Weiran
Published: April 2014

The recent progress in electrical comminution using high‐voltage pulses and the technical challenges in order to bring this technology to the mining industry are outlined. Pre‐weakening ore particles and preferential liberation of minerals at coarse sizes are the two major research outcomes that may have potential benefits for the industry. A particle pre‐weakening characterization method by single‐particle/single‐pulse test has been developed. The emerging challenges for the mining industry to realize the benefits of this novel comminution technology include scale‐up for industrial application, hybrid circuit design, maximization of pulse‐induced cracks, and study of the downstream processing effects.
CFD‐Discrete Element Method Simulations Combined with Compression Experiments to Characterize Stirred‐Media Mills
Authors: Beinert Stefan , Schilde Carsten , Gronau Greta , Kwade Arno
Published: April 2014

Micromechanical aggregate properties are correlated with stress conditions during the dispersion process in a stirred‐media mill. The fracture energy distribution of the aggregates measured via micro‐compression tests is compared with the stress energy distribution in a stirred‐media mill determined by CFD‐discrete element method simulations and by an analytical model. The simulations are likened with a previously conducted one‐way coupling. Furthermore, the rotor speed is varied to identify its influence on stress energy and number of contacts. Using the stress energy distribution and the measured fracture distribution, an effective dispersion fraction can be calculated and correlated with the dispersion progress.
Evaluation of Impact Velocity and Compression Force of Moist Zeolite 4A Granules at Breakage using an Equivalence Function
Authors: Mueller Peter , Aman Sergej , Tomas Juergen
Published: April 2014

Moist, spherical zeolite 4A granules were tested by compression at a constant loading velocity until primary breakage, and were also rectilinearly accelerated and impacted to achieve breakage using a pneumatic canon. The compressive breakage force and the impact breakage velocity distributions were determined. The results obtained by compression and impact tests were evaluated using the model from Rozenblat et al. The results show that the empirical model originally applied for polydisperse particle population is valid for different moisture contents as well. Furthermore, moisture content is found to strongly influence material behavior, where the breakage force and the breakage displacement both decrease with increasing moisture content due to the interactions of zeolite 4A granules with water.
A Highly Fluorescent Metallosalalen‐Based Chiral Cage for Enantioselective Recognition and Sensing
Authors: Dong Jinqiao , Zhou Yanfang , Zhang Fangwei , Cui Yong
Published: April 2014

A highly fluorescent coordination cage [Zn8L4I8] has been constructed by treating enantiopure pyridyl‐functionalized metallosalalen units (L) with zinc(II) iodide and characterized by a variety of techniques including microanalysis, thermogravimetric analysis (TGA), circular dichroism (CD) spectroscopy, and single‐crystal and powder X‐ray diffraction. Strong intermolecular π–π, CH⋅⋅⋅π, and CH⋅⋅⋅I interactions direct packing of the cage molecules to generate a 3D polycage network interconnected by pentahedral cages formed by adjacent pentamers. The cage has an amphiphilic helical cavity decorated with chiral NH functionalities capable of interactions with guest species such as saccharides. The fluorescence of the cage was greatly enhanced by five enantiomeric saccharides in solution, with enantioselectivity factors of 2.480–4.943, and by five enantiomeric amines in the solid state, with enantioselective fluorescence enhancement ratios of 1.30–3.60. This remarkable chiral sensing of both saccharides and amines with impressive enantioselectivity may result from the steric confinement of the cavity as well as its conformational rigidity. It holds great promise for the development of novel chiral cage materials for sensing applications.
Ruthenoarenes versus Phenol Derivatives as Axial Linkers for Subporphyrazine Dimers and Trimers
Authors: Caballero Esmeralda , Romero‐Nieto Carlos , Strauß Volker , Rodríguez‐Morgade M. Salomé , Guldi Dirk M. , Sessler Jonathan L. , Torres Tomás
Published: April 2014

The subporphyrazine (SubPz) dimer diboron(III) [μ‐1′,4′‐benzenediolato][bis‐(1,2,6,7,11,12‐hexapropylsubporphyrazinato)] (2) and trimer triboron(III)[μ‐1′,3′,5′‐benzenetriolato][tris‐(1,2,6,7,11,12‐hexapropylsubporphyrazinato)] (4), consisting of SubPz units assembled through their axial positions by hydroquinone‐ and phloroglucinol‐linkers, respectively, have been prepared. Selective ruthenium‐π‐coordination to the linking aromatic rings afforded SubPz arrays 8 and 9, respectively. These latter systems displayed different degrees of electronic communication between the macrocycles relative to 2 and 4 as inferred from analyses of the ground‐ and excited‐state features. For instance, as revealed by time‐resolved pump probe transient absorption spectroscopy, the excited singlet states of dimer 2 and trimer 4 undergo rather rapid deactivation. In contrast, the presence of a ruthenoarene linker, as in 8 and 9, serves to increase the SubPz singlet excited state lifetimes; these now reach values similar to those seen in the case of monomeric SubPz compounds that either do or do not contain ruthenoarene subunits (i.e., 7 and 6, respectively). These findings are ascribed to the redox active nature of the hydroquinone and phloroglucinol linkers in 2 and 4 and a change in the electronics that results from organometallic functionalization.
Influence of the Alkyl Chain Length on the Self‐Assembly of Amphiphilic Iron Complexes: An Analysis of X‐ray Structures
Authors: Schlamp Stephan , Thoma Peter , Weber Birgit
Published: April 2014

Several new amphiphilic iron complexes were synthesised and characterised by single crystal X‐ray structure analysis. The Schiff‐base‐like equatorial ligands contain long alkyl chains in their outer periphery with chain lengths of 8, 12, 16 and 22 carbon atoms. As axial ligands methanol, pyridine, 4‐aminopyridine, 4‐(dimethylamino)pyridine and 1,2‐bis(4‐pyridyl)ethane were used. X‐ray structure analysis of the products reveals different coordination numbers, depending on the combination of equatorial and axial ligand. The driving force for this is the self‐assembly to lipid‐layer‐like arrangements. This can be controlled through the chain lengths and the dimension of the axial ligands in a crystal‐engineering‐like approach. For this an empirical rule is introduced concerning the crystallisation behaviour of the complexes. The efficacy of this rule is confirmed with the crystallisation of an octahedral complex with two docosyl (C22) chains in the outer periphery. The rule is also applied to other ligand systems.
Synthesis of Mesoporous TiO2/SiO2 Hybrid Films as an Efficient Photocatalyst by Polymeric Micelle Assembly
Authors: Li Yunqi , Bastakoti Bishnu Prasad , Imura Masataka , Hwang Soo Min , Sun Ziqi , Kim Jung Ho , Dou Shi Xue , Yamauchi Yusuke
Published: April 2014

Thermally stable mesoporous TiO2/SiO2 hybrid films with pore size of 50 nm have been synthesized by adopting the polymeric micelle‐assembly method. A triblock copolymer, poly(styrene‐b‐2‐vinyl pyridine‐b‐ethylene oxide), which serves as a template for the mesopores, was utilized to form polymeric micelles. The effective interaction of titanium tetraisopropoxide (TTIP) and tetraethyl orthosilicate (TEOS) with the polymeric micelles enabled us to fabricate stable mesoporous films. By changing the molar ratio of TEOS and TTIP, several mesoporous TiO2/SiO2 hybrid films with different compositions can be synthesized. The presence of amorphous SiO2 phase effectively retards the growth of anatase TiO2 crystal in the pore walls and retains the original mesoporous structure, even at higher temperature (650 °C). These TiO2/SiO2 hybrid films are of very high quality, without any cracks or voids. The addition of SiO2 phase to mesoporous TiO2 films not only adsorbs more organic dyes, but also significantly enhances the photocatalytic activity compared to mesoporous pure TiO2 film without SiO2 phase.
Chiral (1,2)‐Diphenylethylene‐Salen Complexes of Triel Metals: Coordination Patterns and Mechanistic Considerations in the Isoselective ROP of Lactide
Authors: Maudoux Nicolas , Roisnel Thierry , Dorcet Vincent , Carpentier Jean‐François , Sarazin Yann
Published: April 2014

The synthesis of enantiomerically pure aluminium, gallium and indium complexes supported by chiral (R,R)‐(HHONNOHH) (1), (R,R)‐(MeHONNOHMe) (2), (R,R)‐(tButBuONNOtButBu) (3), (R,R)‐(MeNO2ONNOMeNO2) (4), (R,R)‐(HOMeONNOHOMe) (5) and (R,R)‐(ClClONNOClCl) (6) (1,2)‐diphenylethylene‐salen ligands is described. Several of these complexes have been crystallographically authenticated, which highlights a diversity of coordination patterns. Whereas all Ga complexes form [Ga2(CH2SiMe3)4(ONNO)] bimetallic species (ONNO=1–3), aluminium [AlR(ONNO)] (R=Me, CH2SiMe3) and indium [In(CH2SiMe3)(ONNO)] derivatives are monometallic for ONNO=1, 2 and 4–6, and only form the bimetallic complexes [Al2R4(ONNO)] and [In2(CH2SiMe3)4(ONNO)] for the most sterically crowded ligand 3. The [AlMe(ONNO)] complexes react with iPrOH to give [AlOiPr(ONNO)] complexes that are robust towards further iPrOH. The [In(CH2SiMe3)(ONNO)] congeners are inert towards excess alcohol, whereas the Ga compounds decompose easily. All these alkyl complexes, as well as the [AlOiPr(ONNO)] derivatives, catalyse the ring‐opening polymerisation (ROP) of racemic lactide (rac‐LA). The [AlMe(ONNO)] complexes require additional alcohol to afford controlled reactions, but [AlOiPr(ONNO)] complexes are single‐component catalysts for the isoselective ROP of rac‐LA, with values of Pm in the range 0.80–0.90. Experimental evidence unexpectedly shows that chain‐end control leads to the isoselectivity of these aluminium catalysts; also, the more crowded the coordination sphere, the higher the isoselectivity. The bimetallic Ga complexes do not afford controlled reactions, but the binary [In(ONNO)(CH2SiMe3)/(PhCH2OH)] systems competently mediate non‐stereoselective ROP; evidence is given that an activated monomer mechanism is at work. Kinetic studies show that catalytic activity decreases when electronic density and steric congestion at the metal atom increase.
Arginine Side Chains as a Dispersant for Individual Single‐Wall Carbon Nanotubes
Authors: Hirano Atsushi , Tanaka Takeshi , Kataura Hiromichi , Kameda Tomoshi
Published: April 2014

Charged peptides and proteins disperse single‐wall carbon nanotubes (SWCNTs) in aqueous solutions. However, little is known about the role of their side chains in their interactions with SWCNTs. Homopolypeptide–SWCNT systems are ideal for investigating the mechanisms of such interactions. In this study, we demonstrate that SWCNTs are individually dispersed by poly‐L‐arginine (PLA). The debundled SWCNTs exhibited a distinct fluorescence. The dispersibility of SWCNTs with PLA was greater than that of SWCNTs with poly‐L‐lysine (PLL). Molecular dynamics simulations suggest that the side chains of PLA have stronger interactions with the sidewalls of SWCNTs compared with those of PLL. The guanidinium group at the end of the side chain of an arginine residue plays an important role in the interaction with SWCNTs, likely through hydrophobic, van der Waals, and π–π interactions. PLA can be useful as a tool for the dispersion of SWCNTs and can be used to non‐covalently anchor materials to SWCNTs with strong binding.
The Synthesis of Benzimidazoles and Quinoxalines from Aromatic Diamines and Alcohols by Iridium‐Catalyzed Acceptorless Dehydrogenative Alkylation
Authors: Hille Toni , Irrgang Torsten , Kempe Rhett
Published: April 2014

Benzimidazoles and quinoxalines are important N‐heteroaromatics with many applications in pharmaceutical and chemical industry. Here, the synthesis of both classes of compounds starting from aromatic diamines and alcohols (benzimidazoles) or diols (quinoxalines) is reported. The reactions proceed through acceptorless dehydrogenative condensation steps. Water and two equivalents of hydrogen are liberated in the course of the reactions. An Ir complex stabilized by the tridentate P^N^P ligand N2,N6‐bis(di‐isopropylphosphino)pyridine‐2,6‐diamine revealed the highest catalytic activity for both reactions.
Temperature Sensitivity and Soil Organic Carbon Pools Decomposition under Different Moisture Regimes: Effect on Total Microbial and Enzymatic Activity
Authors: Hassan Waseem , Bano Rizwana , Khatak Bashir Ullah , Hussain Imtiaz , Yousaf Mohummad , David Julie
Published: April 2014

The soils of the world store significantly more carbon than present in the atmosphere. However, there is still no consensus regarding the effects of climate change, i.e. increase in temperature on global soil carbon stocks. An incubation experiment was conducted under a temperature range (5–45°C) and moisture conditions, i.e. U1–U5 (20–100% water‐holding capacity) with the objective to investigate temperature sensitivity of labile and recalcitrant organic carbon pools, total microbial activity, and soil extracellular enzymes, i.e. phenol oxidase and catalase activity in an Ultisol soil. The maximum increase in the labile organic carbon pool, i.e. water soluble organic carbon (3.52‐fold), microbial biomass carbon (2.31‐fold), readily mineralizable carbon (6.16‐fold), permanganate oxidized organic carbon (2.81‐fold), and reducing sugar carbon (3.97‐fold) was observed at 35°C, whereas the effect at other temperatures was in the order 25 > 45 > 15 > 5°C. The total organic carbon (TOC) tended to decrease with the increased temperature (from 5–35°C), therefore, maximum TOC (14.7 g kg−1) was observed at 5°C, and minimum (1.76 g kg−1) at 45°C. Conversely, the highest increase (6.48‐fold) in the recalcitrant organic carbon pool was noticed at 45°C, and the impact of other temperatures was in the order 35 > 25 > 15 > 5°C. The maximum increase in the total microbial activity (13.68‐fold) and soil enzymes, phenol oxidase and catalase (3.94 and 3.98‐fold, respectively) activity was observed at 35°C, while the influence of other temperature ranges was in the order 25 > 45 > 15 > 5°C. The effect of moisture regimes on the temperature sensitivity of organic carbon pools, total microbial and enzymatic activity was in the order U3 > U4 > U2 > U1 > U5.
Hexavalent Chromium Removal from Solutions: Surface Efficacy and Characterizations of Three Iron Containing Minerals
Authors: Baig Shams Ali , Wang Qian , Wang Zhuoxing , Zhu Jin , Lou Zimo , Sheng Tiantian , Xu Xinhua
Published: April 2014

In the present study, coupled reduction–sorption of Cr(VI) using three iron containing minerals (magnetite, hematite, and pyrrhotite) in aqueous solutions was investigated as a function of solution pH, contact time, and particle size. Detailed characterizations were performed using Brunauer–Emmett–Teller (BET), environmental scanning electron microscopy, and X‐ray diffraction (XRD) techniques. Results demonstrated that over 99% of Cr(VI) removal was achieved just after 1 min of the reaction using pyrrhotite with particle size (100–200 mesh). In comparison, removal efficiency of hematite and magnetite against Cr(VI) was below 40% after 2 h of the reaction. Acidic aqueous medium proved effective for Cr(VI) removal and nearly 100% Cr(VI) removal was achieved at pH 3 using pyrrhotite (30–40 mesh), while the surface efficacy of hematite and magnetite has also improved in acidic solution. In terms of removal efficiency, the three minerals followed the order: pyrrhotite > magnetite > hematite. However, no significant difference in the BET specific surface area was recorded among these minerals, but the mineralogical compositions played an important role for removing Cr(VI) in aqueous solutions. Analysis of XRD pattern revealed that iron contents produce Fe3FeSiO4(OH)5 and FeCr2O4 after the reaction with soluble Cr(VI) and precipitated. This study suggested that high ferrous ions‐based minerals can effectively remove Cr(VI) from contaminated water environments.
Source Separate Collection of Recyclables Reduces Chromium and Nickel Content in Municipal Solid Waste Compost
Authors: López Rafael , Burgos Pilar , Madrid Fernando , Camuña Ignacio
Published: April 2014

The composting process is a widespread option for municipal solid waste (MSW) treatment however the low rate of separate waste collection leads to poor quality composts. The evolution of heavy metal content in composts as a separate collection of dry recyclables became gradually implemented in the metropolitan area of Seville city (1 million inhabitants, SW Spain) is hereby studied. During the last 12 years, Cr, Ni, and Pb contents in compost were reduced by 60, 39, and 31%, respectively, whilst contents of Zn and Cd increased by 20 and 108%. During the same period Cu remained unchanged. The metal content reductions can be related to the separate collection of paper‐cardboard, glass, and package waste from MSW, though materials separately collected were limited to 6.7% of raw MSW production. Extending the source collection of recyclables to separate metallic components and performing slight changes in the mechanical biological treatment would lead to additional reductions in other heavy metals whilst implementing the separate recovery of the organic fraction.