bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of SLA assimilation in the Sicily Channel Regional Model: model skills and mesoscale features
Authors: Olita A. , Dobricic S. , Ribotti A. , Fazioli L. , Cucco A. , Dufau C. , Sorgente R.
Published: February 2012

Abstract. The impact of the assimilation of MyOcean Sea Level Anomalies along track data on the analyses of the Sicily Channel Regional Model was studied. The numerical model has a resolution of 1/32° degrees and is capable to reproduce mesoscale and sub-mesoscale features. The impact of the SLA assimilation is studied by comparing a simulation (SIM, which does not assimilate data) with two analyses, AN0 and AN1, assimilating different reprocessing versions (V0 and V1) of the same set of Along Track altimetric measurements. The quality of the analyses was evaluated by computing RMSE of the misfits between analyses background and observations (sea level) before assimilation. A qualitative evaluation of the ability of the analyses to reproduce mesoscale structures is accomplished by comparing model results with Ocean Color and SST satellite data, able to detect such features on the ocean surface. CTD profiles allowed to evaluate the impact of the SLA assimilation along the water column. We found a significant improvement for AN1 solution in terms of SLA rmse in respect to SIM (the averaged RMSE of AN1 SLA misfits over 1.5 years is about 0.5 cm smaller than SIM) and a weaker improvement in respect to the assimilation of the V0 dataset (0.1 cm average over the same period). Comparison with CTD data shows a questionable improvement produced by the assimilation process in terms of vertical features: AN1 is better in temperature while for salinity it get worse than SIM at the surface. The qualitative comparison of simulation and analyses with synoptic satellite independent data proves that SLA assimilation of V1 data allows to correctly reproduce some dynamical features (above all the circulation in the Ionian portion of the domain) and mesoscale structures otherwise misplaced or neglected both by SIM and AN0.
Evaluation of the criticality of cracks in ice shelves using finite element simulations
Authors: Plate C. , Müller R. , Humbert A. , Gross D.
Published: February 2012

Abstract. The ongoing disintegration of large ice shelf parts in Antarctica raise the need for a better understanding of the physical processes that trigger critical crack growth in ice shelves. Finite elements in combination with configurational forces facilitate the analysis of single surface fractures in ice under various boundary conditions and material parameters. The principles of linear elastic fracture mechanics are applied to show the strong influence of different depth dependent functions for the density and the Young's modulus on the stress intensity factor KI at the crack tip. Ice, for this purpose, is treated as a compressible solid and the consequences of this choice in comparison to the predominant incompressible approaches is discussed. The computed stress intensity factors KI for dry and water filled cracks are compared with critical values KIc from measurements that can be found in literature.
Effect of Chronic L-Dopa or Melatonin Treatments after Dopamine Deafferentation in Rats: Dyskinesia, Motor Performance, and Cytological Analysis
Authors: Gutierrez-Valdez Ana Luisa , Anaya-Martínez Verónica , Ordoñez-Librado José Luis , García-Ruiz Ricardo , Torres-Esquivel Carmen , Moreno-Rivera Montserrat , Sánchez-Betancourt Javier , Montiel-Flores Enrique , Avila-Costa Maria Rosa
Published: February 2012

The present study examines the ability of melatonin to protect striatal dopaminergic loss induced by 6-OHDA in a rat model of Parkinson's disease, comparing the results with L-DOPA-treated rats. The drugs were administered orally daily for a month, their therapeutic or dyskinetic effects were assessed by means of abnormal involuntary movements (AIMs) and stepping ability. At the cellular level, the response was evaluated using tyrosine hydroxylase immunoreactivity and striatal ultrastructural changes to compare between L-DOPA-induced AIMs and Melatonin-treated rats. Our findings demonstrated that chronic oral administration of Melatonin improved the alterations caused by the neurotoxin 6-OHDA. Melatonin-treated animals perform better in the motor tasks and had no dyskinetic alterations compared to L-DOPA-treated group. At the cellular level, we found that Melatonin-treated rats showed more TH-positive neurons and their striatal ultrastructure was well preserved. Thus, Melatonin is a useful treatment to delay the cellular and behavioral alterations observed in Parkinson's disease.
In Silico Experimental Modeling of Cancer Treatment
Authors: Trisilowati  , Mallet D. G.
Published: February 2012

In silico experimental modeling of cancer involves combining findings from biological literature with computer-based models of biological systems in order to conduct investigations of hypotheses entirely in the computer laboratory. In this paper, we discuss the use of in silico modeling as a precursor to traditional clinical and laboratory research, allowing researchers to refine their experimental programs with an aim to reducing costs and increasing research efficiency. We explain the methodology of in silico experimental trials before providing an example of in silico modeling from the biomathematical literature with a view to promoting more widespread use and understanding of this research strategy.
Testing the Ideal Free Distribution Hypothesis: Moose Response to Changes in Habitat Amount
Authors: Stewart Abbie , Komers Petr E.
Published: February 2012

According to the ideal free distribution hypothesis, the density of organisms is expected to remain constant across a range of habitat availability, provided that organisms are ideal, selecting habitat patches that maximize resource access, and free, implying no constraints associated with patch choice. The influence of the amount of habitat on moose (Alces alces) pellet group density as an index of moose occurrence was assessed within the Foothills Natural Region, Alberta, Canada, using a binary patch-matrix approach. Fecal pellet density was compared across 45 sites representing a gradient in habitat amount. Pellet density in moose habitat increased in a linear or quadratic relationship with mean moose habitat patch size. Moose pellet density decreased faster thanwhatwould be expected from a decrease in habitat amount alone. This change in pellet group density with habitat amount may be because one or both of the assumptions of the ideal free distribution hypothesis were violated.
Assessing Barriers to Expansion of Farm-to-Chef Sales: A Case Study from Upstate New York
Authors: Schmit Todd M. , Hadcock Stephen E.
Published: February 2012

Columbia County Bounty is a local organization made up of farmer and culinary business members, with a mission that includes promoting connections between local agricultural producers and culinary businesses. A case study was conducted to address questions raised by CCB related to expanding farm-to-chef marketing in their area. Common barriers for restaurants included larger time commitments, inconvenience, and consistency in product volumes and quality; however, satisfaction with local wholesale distributors may create new opportunities for farmers to work collaboratively with them in including more local products in their distribution. A closer inspection of channel performance by farms in the study will drive changes in future channel strategies and utilization of farm-to-chef marketing, as farms are already benefiting from strong direct marketing channels and restaurants procuring local products from these channels.
Effect of Inulin on the Physical, Chemical and Sensory Quality Attributes of Polish Chicken Burgers
Authors: Cegielka Aneta , Tambor Krzysztof
Published: February 2012

Four formulations of chicken burger were prepared: control product without inulin, and products with 1.0, 2.0 or 3.0 % of inulin (in relation to the weight of meat, fatty raw material, and water), respectively. Physical, chemical and sensory analyses were made to evaluate the effect of inulin on the quality of cooked burgers. The results showed that the application of inulin did not cause significant decrease of the thermal processing yield nor the shear force of the products. However, the addition of inulin resulted in slight, but significant differences (P < 0.05) in chemical composition and energy value of burgers. Burgers of all formulations were acceptable in sensory characteristics. The addition level of inulin not higher than 1.0 %, did not result in deterioration of physical, chemical and sensory quality characteristics of chicken burgers. To improve the nutritional value of chicken burgers, the modification of fatty acid composition is recommended.
 
Finite Element Modeling and Physical Property Estimation of Rheological Food Objects
Authors: Wang Zhongkui , Hirai Shinichi
Published: February 2012

The purpose of this study is to accurately simulate the rheological behaviors of food objects undergoing a loading-unloading operation using finite element (FE) model. Due to the presence of residual deformation, it is difficult to model rheological behaviors. Especially, it is hard to accurately reproduce both rheological force and residual deformation simultaneously. In this study, objects made of food materials were tested. Force and deformation measurements were recorded for parameter estimation. Constitutive models were investigated for describing rheological behaviors. A parallel five-element model including two dual-moduli viscous elements was proposed to accurately predict both rheological force and residual deformation simultaneously. 2D/3D FE model was formulated for simulating rheological behaviors. To estimate the parameters, an effective four-step method was established based on nonlinear optimization which aimed at minimizing the differences of forces and deformation between simulation and experiments. The proposed FE model and parameter estimation method were validated in both 2D and 3D cases and good agreements were achieved in both rheological forces and deformation between numerically simulated and experimentally measured data.
Radioligand Binding Analysis as a Tool for Quality Control of GPCR Production for Structural Characterization: Adenosine A2aR as a Template for Study
Authors: Singh Shweta , Zhang Minghao , Bertheleme Nicolas , Kara Elodie , Strange Philip G. , Byrne Bernadette
Published: February 2012

Functional characterization of G protein–coupled receptors is essential to ascertain the suitability of a protein target for downstream studies and to help develop optimal expression and isolation procedures. Radioligand binding analysis is a well‐established technique, which allows direct measurement of the amount of functional receptor in a sample. It can be readily applied to both membrane‐bound and soluble receptor samples and is an ideal method for monitoring the amount of functional protein at each stage in the expression and isolation process. This unit presents protocols for the radioligand binding analysis of the human adenosine A2a receptor and provides examples of how these assays can be used at several stages to help optimize expression, solubilization, and isolation procedures.
Hip pain while using lower extremity joints and sleep disturbances in elderly white women: Results from a cross‐sectional analysis
Authors: Parimi Neeta , Blackwell Terri , Stone Katie L. , Lui Li‐Yung , Ancoli‐Israel Sonia , Tranah Gregory J. , Hillier Teresa A. , Nevitt Michael E. , Lane Nancy E. ,   for the Study of Osteoporotic Fractures Study Group
Published: February 2012

Objective

To evaluate sleep quality in women with hip pain due to daily activities involving the lower extremity joints.

Methods

We evaluated the association of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) hip pain severity score with objective sleep measures obtained by wrist actigraphy in 2,225 white women ≥65 years of age enrolled in the Study of Osteoporotic Fractures.

Results

Women had an increased odds of spending ≥90 minutes awake after sleep onset (odds ratio [OR] 1.28, 95% confidence interval [95% CI] 1.11–1.50) for every 5‐point increase in hip pain score after adjustment for all covariates. Hip pain when sitting or lying was the strongest predictor of sleep fragmentation (OR 2.0, 95% CI 1.47–2.73); however, standing pain was associated with a higher number of awake minutes in bed scored from sleep onset to the end of the last sleep episode, independent of pain while in bed (OR 1.41, 95% CI 1.07–2.01). Sleep disturbances increased significantly after the first 2 hours of sleep in women with severe hip pain compared to those without hip pain (mean ± SD 1.4 ± 0.47 minutes per hour of sleep; P < 0.003). Similar associations were observed for long wake episodes >5 minutes. There were no associations between daytime napping, sleep latency, sleep efficiency, and total sleep minutes and WOMAC hip pain.

Conclusion

Fragmented sleep was greater in women with hip pain compared to those without hip pain; however, fragmented sleep in women with severe hip pain compared to those without hip pain was unchanged until after the first 2 hours of sleep. Further investigations into pain medications wearing off over time or the prolonged periods of inactivity decreasing the pain threshold are warranted.
Catalytic Epoxidation of Alkenes by the Manganese Complex of a Reduced Porphyrinogen Macrocycle
Authors: Bruyneel Frederic , Letondor Christophe , Bastürk Bjorn , Gualandi Andrea , Pordea Anca , Stoeckli‐Evans Helen , Neier Reinhard
Published: February 2012

The present paper details the first application of a fully reduced meso‐octamethylporphyrinogen macrocycle as an effective ligand for simple operative manganese‐catalyzed alkene epoxidation. The efficiency of the novel catalyst was determined in the presence of various oxidants, apical ligands and acidic/basic additives. Higher reactivity was found in favour of electron‐rich alkenes, whereas an electron‐deficient conjugated alkene appeared as a poor substrate in the screening. Sulfur additives were active as apical ligands, whereas nitrogen‐containing additives influenced the reactivity only moderately. cis‐Stilbene and 3β‐acetoxy‐5‐cholestene were epoxidized in a stereoselective manner. The X‐ray structures of the new manganese complexes were determined and showed a rigid planar coordination geometry of the saturated macrocyclic ligand to the metal centre.
Experimental study on the heating effects of microwave discharge caused by metals
Authors: Wang Wenlong , Liu Zhen , Sun Jing , Ma Qingluan , Ma Chunyuan , Zhang Yunli
Published: February 2012

The heating effects of discharge triggered at the appearance of metals are important under microwave irradiation but special studies have rarely been carried out. In our experiments, the heat generation was successfully isolated by embedding metal in quartz sand and measured through an indirect calorimetric method. All the experiments and analyses indicate that the discharge triggered by metals under microwave irradiation has remarkable heating effects. The microwave power, irradiation time, metal amount, and atmosphere are all important factors to influence the discharge intensity and then the heating effects. The understanding of the effects of metal discharge will help us to further research on the treatment of solid waste, such as the microwave pyrolysis of electrical waste. It may also be a good idea to use the discharge phenomena and their heating effects by embedding some metals to the microwave field in some certain applications. © 2012 American Institute of Chemical Engineers AIChE J, 2012
Mesenchymal stem cells restore cortical rewiring after neonatal ischemia in mice
Authors: van Velthoven Cindy T. J. , van de Looij Yohan , Kavelaars Annemieke , Zijlstra Jitske , van Bel Frank , Huppi Petra S. , Sizonenko Stéphane , Heijnen Cobi J.
Published: February 2012

Objective:

A study was undertaken to investigate the effect of neonatal hypoxic‐ischemic (HI) brain damage and mesenchymal stem cell (MSC) treatment on the structure and contralesional connectivity of motor function‐related cerebral areas.

Methods:

Brain remodeling after HI±MSC treatment in neonatal mice was analyzed using diffusion tensor magnetic resonance imaging, immunohistochemistry, anterograde tracing with biotinylated dextran amine (BDA), and retrograde tracing with fluorescent pseudorabies virus (PRV).

Results:

MSC treatment after HI reduced contralesional rewiring taking place after HI. Following MSC treatment, fractional anisotropy values, which were increased in both ipsi‐ and contralesional cortices and decreased in the corpus callosum (CC) after HI, were normalized to the level observed in sham‐operated mice. These results were corroborated by myelin basic protein intensity and staining pattern in these areas. Anterograde tracing of ipsilesional motor neurons showed that after MSC treatment, fewer BDA‐positive fibers crossed the CC and extended into the contralesional motor cortex compared to HI mice. This remodeling was functional, because retrograde labeling showed increased connectivity between impaired (left) forepaw and the contralesional (left) motor cortex after HI, whereas MSC treatment reduced this connection and increased the connection between the impaired (left) forepaw and the ipsilesional (right) motor cortex. Finally, the extent of contralesional rewiring measured with BDA and PRV tracing was related to sensorimotor dysfunction.

Interpretation:

This is the first study to describe MSC treatment after neonatal HI markedly reducing contralesional axonal remodeling induced by HI brain injury. ANN NEUROL 2012;71:785–796
Symptomatic intracranial hemorrhage after stroke thrombolysis: The SEDAN Score
Authors: Strbian Daniel , Engelter Stefan , Michel Patrik , Meretoja Atte , Sekoranja Lucka , Ahlhelm Frank J. , Mustanoja Satu , Kuzmanovic Igor , Sairanen Tiina , Forss Nina , Cordier Maria , Lyrer Philippe , Kaste Markku , Tatlisumak Turgut
Published: February 2012

Objective:

A study was undertaken to develop a score for assessing risk for symptomatic intracranial hemorrhage (sICH) in ischemic stroke patients treated with intravenous (IV) thrombolysis.

Methods:

The derivation cohort comprised 974 ischemic stroke patients treated (1995–2008) with IV thrombolysis at the Helsinki University Central Hospital. The predictive value of parameters associated with sICH (European Cooperative Acute Stroke Study II) was evaluated, and we developed our score according to the magnitude of logistic regression coefficients. We calculated absolute risks and likelihood ratios of sICH per increasing score points. The score was validated in 828 patients from 3 Swiss cohorts (Lausanne, Basel, and Geneva). Performance of the score was tested with area under a receiver operating characteristic curve (AUC‐ROC).

Results:

Our SEDAN score (0 to 6 points) comprises baseline blood Sugar (glucose; 8.1–12.0mmol/l [145–216mg/dl] = 1; >12.0mmol/l [>216 mg/dl] = 2), Early infarct signs (yes = 1) and (hyper)Dense cerebral artery sign (yes = 1) on admission computed tomography scan, Age (>75 years = 1), and NIH Stroke Scale on admission (≥10 = 1). Absolute risk for sICH in the derivation cohort was: 1.4%, 2.9%, 8.5%, 12.2%, 21.7%, and 33.3% for 0, 1, 2, 3, 4, and 5 score points, respectively. In the validation cohort, absolute risks were similar (1.0%, 3.5%, 5.1%, 9.2%, 16.9%, and 27.8%, respectively). AUC‐ROC was 0.77 (0.71–0.83; p < 0.001).

Interpretation:

Our SEDAN score reliably assessed risk for sICH in IV thrombolysis‐treated patients with anterior‐ and posterior circulation ischemic stroke, and it can support clinical decision making in high‐risk patients. External validation of the score supports its generalization. ANN NEUROL 2012;
A novel negative dielectric constant material based on phosphoric acid doped poly(benzimidazole)
Authors: Gordon Keith L. , Kang Jin Ho , Park Cheol , Lillehei Peter T. , Harrison Joycelyn S.
Published: February 2012

Metamaterials or artificial negative index materials (NIMs) have generated great attention because of their unique electromagnetic properties. The main challenge in current NIM development is creating a homogenous NIM without the need of complex geometric architectures consisting of capacitors and inductors or aggregated fillers, but possessing a tunable plasma frequency. A natural material that can exhibit negative values for permittivity and permeability simultaneously has not been found, or discovered. If one can design a negative dielectric constant material with a tunable plasma frequency of interest, implementing negative permeability into the material or system would be much more readily achievable to create a metamaterial. In this regard, a novel negative dielectric constant material, which is an essential key to creating the NIMs, was developed by doping ions into a polymer, a protonated poly(benzimidazole) (PBI). The doped PBI showed a negative dielectric constant at frequencies of kHz to MHz because of its reduced plasma frequency and an induction effect. As temperature increased, the dielectric spectrum changed from a relaxation to a resonance behavior and exhibited a larger magnitude of negative dielectric constant at a lower frequency. The conductivity of the doped PBI measured as a function of both temperature and frequency followed the same trend as the dielectric constant. With respect to the dielectric constant and the conductivity data, it can be assumed that the origin of the negative dielectric constant is attributed to the resonance behavior of the highly mobile ions at elevated temperatures and high frequencies. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Investigation of the stereodefect distribution and conformational behavior of isotactic polypropylene polymerized with different Ziegler–Natta catalysts
Authors: Kang Jian , Yang Feng , Wu Tong , Li Huilin , Liu Dongming , Cao Ya , Xiang Ming
Published: February 2012

Two isotactic polypropylene (iPP) samples (PP‐A and PP‐B) were obtained by utilizing two different heterogeneous Ziegler–Natta catalysts in a given polymerization system. The molecular structure and conformational behavior of the samples were studied. The results of determination of xylene soluble material (XS) and 13C NMR showed that the average isotacticity of the samples were nearly same. However, the results of high‐resolution high‐temperature 13C NMR (HRHT 13C NMR) and successive self‐nucleation and annealing (SSA) fractionation revealed that the amount of high isotacticity of PP‐B was lower than that of PP‐A, and the amount of relative medium and low isotacticity of PP‐B was higher than PP‐A, indicating that the stereodefect distribution of PP‐B was more uniform than PP‐A. The calculation of average meso sequence length from SSA was found to be in good agreement with that calculated from the results of HRHT 13C NMR. Moreover, Fourier transformation infrared was utilized to study the influence of stereodefect distribution on the conformational behavior of iPP. The result suggested that the molecular conformation of the PP‐B was more disordered than PP‐A, the regularity of molecular structure for PP‐B was lower than that of PP‐A. The related action mechanism and the influences of which on crystallization behavior were discussed. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and characterization of biodegradable poly(butylene succinate)‐co‐oligo(L‐valine) copolyesters via direct melt transesterification
Authors: Ye Suwen , Tan Licheng , Chen Yiwang , Wei Junchao , Zhou Weihua
Published: February 2012

A series of aliphatic biodegradable poly(butylene succinate)‐co‐oligo(L‐valine) (PBSVAL) copolyesters were synthesized with dimethyl succinate, 1,4‐butanediol (BDO), and oligo(L‐valine) (OVL) as reagents. The GPC results show that the weight average molecular weight (Mw) of the copolyester with a feed ratio (PBS/OVL) of 0.9/0.1 (PBSVAL10) is 4.9 × 104 g/mol, and its polydispersity index is 1.68. All the copolyesters were more thermally stable than the pristine poly(butylene succinate) (PBS). The incorporation of valine units into the copolyesters eventually led to the decrease of the crystallization temperature, melting temperature, while increase of crystallization enthalpy and melting enthalpy. The crystal structure of the copolyesters is similar to pure PBS except for higher degrees of crystallinity; also there was a trend to higher degrees of crystallinity with increasing content of valine. From the enzymatic degradation experiment, it is clear that the PBSVAL10 copolyester shows less weight loss as compared to pure PBS which is due to PBSVAL10 with higher degree of crystallinity. The morphology of the copolyester films after degradation was also studied by the scanning electron microscopy. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of superporous hydrogels by a postpolymerization foaming protocol and their water absorbent behavior
Authors: Gong Ruiying , Kang Ning , Mu Youbing , Li Jianzhong , Wan Xiaobo
Published: February 2012

The rate of swelling is one of the most important parameters of hydrogel polymeric networks; therefore, the objective of this study was to develop a new method to synthesize superporous poly(acrylic acid‐co‐acrylamide) hydrogels to improve swelling rate. The hydrogel was prepared in the presence of a foaming agent (comprising azodicarbonamide and zinc oxide), using 2,2′‐Azobis[2‐(2‐imidazolin‐2‐yl)propane] dihydrochloride as the initiator. The N2 released during the polymerization led to the formation of a slightly foamed gel; we refer to the process as a prefoaming process. The obtained gel underwent a further foaming process to form a superporous hydrogel. Unlike in existing methods, the consistent time control of the foaming agent addition and the onset of gelling were not necessary in this simplified gel preparation procedure. The water absorbent behavior of the superporous hydrogels suggested that the polymers obtained from the prefoaming process reached the swelling equilibrium more rapidly than those with little prefoaming, and their absorbent capacity was greater. Scanning electron microscope images show that interconnected pores inside these superporous gels formed capillary channels, which are critical for the fast swelling rate. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation and characterization of double‐layered microencapsulated red phosphorus and its flame retardance in poly(lactic acid)
Authors: Chang Shaokun , Zeng Chao , Yuan Weizhong , Ren Jie
Published: February 2012

A novel double‐layered microencapsulated red phosphorus (DMRP) has been prepared through chemical precipitation of aluminum trihydrate (ATH) and in situ polymerization of melamine formaldehyde (MF) resin on the red phosphorus (RP) powder surface, and its structure was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The influence of DMRP on flame retardance and thermal stability of poly(lactic acid) (PLA) was thoroughly investigated by means of X‐ray diffractometry (XRD), limiting oxygen index (LOI), vertical burning test, and thermogravimetric analysis (TGA). With an optimum mass ratio of RP/ATH/MF = 72.25%/12.75%/15%, it has been found that PLA with the addition of DMRP at 25 wt % loading level shows good flame retardance compared to plain RP as well as the conventional microencapsulated red phosphorus (CMRP), and can achieve UL94 V‐0 rating along with an LOI increase from 20.5 to 29.3. The TGA and XRD studies indicate that the interaction occurs among all three components: RP, ATH, and MF resin. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of different rapeseed‐oil‐based polyols on mechanical properties of flexible polyurethane foams
Authors: Rojek Piotr , Prociak Aleksander
Published: February 2012

Two rapeseed‐oil‐based polyols were synthesized by partial epoxidation of the double bonds in fatty acid chains and overall opening oxirane rings by using diethylene glycol. Flexible polyurethane foams with varied isocyanate index and modified by partial substitution of petrochemical polyether triol with rapeseed‐oil‐derived polyols were obtained. Bio‐polyols: Polyol I and Polyol II differed in functionalities (2.5 and 5.2, respectively) and hydroxyl values (114 and 196 mg KOH/g, respectively). Influence of the bio‐polyols on mechanical properties, resilience, apparent density, and cellular structure of synthesized foams was investigated. Compression properties were examined and compared via determining compression values and compression stress—strain characteristics, as well as tensile strength and elongation at break were estimated. Foams modified with Polyol I had higher values of resilience and elongation at break than those with Polyol II, while higher tensile and compression strength and superior cell structure were observed in the case of foams modified with Polyol II. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and Spectroscopic Properties of Phthalocyanine–[60]Fullerene Conjugates Connected Directly by Means of a Four‐Membered Ring
Authors: Fukuda Takamitsu , Kikukawa Yuu , Takaishi Shiori , Kobayashi Nagao
Published: February 2012

New covalently C60‐conjugated phthalocyanine (Pc) analogues in which the Pc and C60 components are connected by means of a four‐membered ring have been synthesized by taking advantage of a [2+2] cycloaddition reaction of C60 with benzyne units generated from either a phthalocyanine derivative (8) or its precursor (1). The reaction of 1 with PhI(OAc)2 and trifluoromethanesulfonic acid (TfOH) followed by the [2+2] cycloaddition of C60 in the presence of tetra‐n‐butylammonium fluoride (TBAF) yielded the C60‐substituted Pc precursor (3). Mixed condensation of 3 and 4,5‐dibutylsulfonylphthalonitrile (4) in a thermally promoted template reaction using a nickel salt successfully gave the Pc–C60 conjugate (5). Results of mass spectrometry and 1H and 13C NMR spectroscopy clearly indicate the formation of the anticipated Pc–C60 conjugate. Direct coupling of C60 with the Pc analogue that contained eight peripheral trimethylsilyl (TMS) groups (8) also proceeded successfully, such that mono and bis C60‐adducts were detected by their mass, although the isolation of each derivative was difficult. The absorption and magnetic circular dichroism (MCD) spectra of 5 and the reference compound (7) differ from each other in the Q‐band region, thereby suggesting that the presence of the C60 moiety affects the electronic structure of the conjugate. The reduction and oxidation potentials of 5 and 7 obtained by cyclic voltammetry are comparative, except for the C60‐centered reduction couple at −1.53 V versus Fc+/Fc in o‐dichlorobenzene (o‐DCB). A one‐electron reduction of 5 and 7 in tetrahydrofuran (THF) by using the sodium mirror technique results in the loss of band intensity in the Q‐band region, whereas the characteristic marker bands for Pc‐ring‐centered reduction appear at around 430, 600, and 900 nm for both compounds. The final spectral shapes of 5 and 7 upon the reduction resemble each other, thus indicating that no significant molecular orbital (MO) interactions between the C60 and Pc units are present for the reduced species of 5. In contrast, the oxidized species of 5 and 7 generated by the addition of NOBF4 in CH2Cl2 show significantly different absorption spectra from each other. Whereas the broad bands at approximately 400–550 nm of 7+ are indicative of the cationic π‐radical species of metallo‐Pcs and can be assigned to a transition from a low‐lying MO to the half‐filled MO, no corresponding bands were observed for 5+. These spectral characteristics have been tentatively assigned to the delocalized occupied frontier MOs for 5+. The experimental results are broadly supported by DFT calculations.
Synthesis of Olive‐Shaped Mesoporous Platinum Nanoparticles (MPNs) with a Hard‐Templating Method Using Mesoporous Silica (SBA‐15)
Authors: Wang Hongjing , Imura Masataka , Nemoto Yoshihiro , Park Sang‐Eon , Yamauchi Yusuke
Published: February 2012

Well‐ordered mesoporous Pt nanoparticles (MPNs) with uniform olive shapes are synthesized by using two‐dimensional (2D) hexagonal mesoporous silica (SBA‐15) as a hard template. The average particle sizes are controllable in the range of 150 to 230 nm by changing the reduction time. Low‐angle XRD profiles for the obtained MPNs show three distinct peaks assignable to the (10), (11), and (20) planes of a highly ordered 2D hexagonal symmetry. From high‐magnification SEM images, periodically arranged Pt nanowires are observed clearly, which are a negative replica of the 2D hexagonally ordered mesoporous silica (SBA‐15). Furthermore, the single crystallinity of the Pt fcc structure coherently extends over the whole particles. As a result of such unique character as well as high surface area, the obtained MPNs show distinctly enhanced electrocatalytic properties for methanol oxidation reaction compared to other Pt samples, such as Pt black.
Accounting for the constrained availability of land: a comparison of bio‐based ethanol, polyethylene, and PLA with regard to non‐renewable energy use and land use
Authors: Bos Harriëtte L. , Meesters Koen P.H. , Conijn Sjaak G. , Corré Wim J. , Patel Martin K.
Published: February 2012

In a bio‐based economy, chemicals, materials, biofuels, and other forms of energy will be produced from biomass. Pressure on agricultural land will thus increase, calling for highly efficient solutions in terms of land use, with minimal environmental impacts. In order to gain better insight into the available options and their trade‐offs, this perspective studies the production of polylactic acid (PLA), bioethanol, and bio‐based polyethylene (PE) from wheat, maize, sugarbeet, sugarcane, and Miscanthus. While in current agricultural practice some plants are harvested and used as whole crop (e.g. Miscanthus), for others only part of the plant is used, with the remainder being returned to the field (e.g. wheat straw). In order to obtain an understanding of the unused potential we assume as default case that all agricultural residues and processing co‐products are used for energy purposes, thereby replacing non‐renewable energy. We conclude that this agricultural practice would allow to substantially reduce non‐renewable energy use (NREU). We also find a clear difference in ranking depending on whether we study (i) NREU per (metric) tonne of product or (ii) Avoided NREU per hectare of land. The latter seems a suitable choice in a world where land availability is limited. In this case, we identify PLA as the preferred choice, irrespective of the type of crop. The production of ethanol for the replacement of fuels scores as the worst option for all crops. For each of the products studied, sugarcane offers the highest savings per hectare followed by sugarbeet. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd
Electric field and current density distribution in an anatomical head model during transcranial direct current stimulation for tinnitus treatment
Authors: Parazzini Marta , Fiocchi Serena , Ravazzani Paolo
Published: February 2012

Tinnitus is considered an auditory phantom percept. Recently, transcranial direct current stimulation (tDCS) has been proposed as a new approach for tinnitus treatment including, as potential targets of interest, either the temporal and temporoparietal cortex or prefrontal areas. This study investigates and compares the spatial distribution of the magnitude of the electric field and the current density in the brain tissues during tDCS of different brain targets. A numerical method was applied on a realistic human head model to calculate these field distributions in different brain structures, such as the cortex, white matter, cerebellum, hippocampus, medulla oblongata, pons, midbrain, thalamus, and hypothalamus. Moreover, the same distributions were evaluated along the auditory pathways. Results of this study show that tDCS of the left temporoparietal cortex resulted in a widespread diffuse distribution of the magnitude of the electric fields (and also of the current density) on an area of the cortex larger than the target brain region. On the contrary, tDCS of the dorsolateral prefrontal cortex resulted in a stimulation mainly concentrated on the target itself. Differences in the magnitude distribution were also found on the structures along the auditory pathways. A sensitivity analysis was also performed, varying the electrode position and the human head models. Accurate estimation of the field distribution during tDCS in different regions of the head could be valuable to better determine and predict efficacy of tDCS for tinnitus suppression. Bioelectromagnetics 33:476–487, 2012. © 2012 Wiley Periodicals, Inc.
Site‐Selective Suzuki–Miyaura and Sonogashira Cross Coupling Reactions of the Bis(triflate) of 2,4′‐Bis(hydroxy)diphenyl Sulfone
Authors: Khera Rasheed Ahmad , Ali Asad , Hussain Munawar , Ibad Muhammad Farooq , Villinger Alexander , Langer Peter
Published: February 2012

Described is the synthesis of novel arylated and alkynylated 2,4′‐diphenyl sulfones based on what are, to the best of our knowledge, the first palladium(0)‐catalyzed cross‐coupling reactions of bis(triflates) of 2,4′‐bis(hydroxy)diphenyl sulfone. The reactions proceed with very good site‐selectivity.
Mg‐Silicate Carbonation Based on an HCl‐ and NH3‐Recyclable Process: Effect of Carbonation Temperature
Authors: Zhang J. , Zhang R. , Geerlings H. , Bi J.
Published: February 2012

A new indirect mineral carbonation process is studied which could mitigate anthropogenic CO2 emissions. In this process, magnesium silicate is dissolved in HCl and the resulting MgCl2 solution is subsequently reacted with CO2 in NH3. HCl and NH3 are recovered from NH4Cl in a two‐step thermal decomposition. Carbonation is investigated from 30 °C to 180 °C at 4 MPa CO2 pressure and Mg‐carbonate morphology transformations with increasing temperature are identified. Nesquehonite (MgCO3 · 3H2O) is obtained below 70 °C, hydromagnesite (Mg5(CO3)4(OH)2 · 4H2O) is formed at 100 °C, and further temperature increase to 180 °C leads to magnesite (MgCO3) precipitation. Nesquehonite and magnesite can fix more CO2 per mole Mg than hydromagnesite.
Designer Ionic Liquid Crystals Based on Congruently Shaped Guanidinium Sulfonates
Authors: Butschies Martin , Frey Wolfgang , Laschat Sabine
Published: February 2012

Ionic liquid crystals are mesogenic compounds that consist of cations and anions, usually rod‐like cations and spherical anions. Herein we report a new method for the synthesis of ionic liquid crystals by using cations and anions of the same molecular shape with oppositely charged head groups. Thus, 4‐alkoxyphenylpentamethylguanidinium 4‐alkoxyphenylsulfonate ion pairs have been synthesised. 4‐Alkoxyphenylpentamethylguanidinium iodides were also prepared to determine the influence of congruently shaped anions, in comparison with their spherical counterparts, on mesophase behaviour, which was investigated by differential scanning calorimetry (DSC), polarising optical microscopy (POM) and X‐ray diffraction (XRD). All the liquid crystalline salts exhibit smectic A mesophases with strongly interdigitated bilayer structures. The guanidinium sulfonate ion pairs show mesomorphic properties from shorter alkyl chain lengths (≥C9) and lower melting points (≈10 K), whereas the corresponding guanidinium iodides are liquid crystalline for longer alkyl chain lengths (≥C14). For chains with ≥C18, however, the mesophase range decreases for the sulfonate ion pairs, but not for the iodide salts.
ansa‐Rare‐Earth‐Metal Catalysts for Rapid and Stereoselective Polymerization of Renewable Methylene Methylbutyrolactones
Authors: Hu Yangjian , Miyake Garret M. , Wang Baoli , Cui Dongmei , Chen Eugene Y.‐X.
Published: February 2012

Two ansa‐half‐sandwich rare‐earth‐metal (REM) dialkyl complexes supported by an ethylene‐bridged fluorenyl (Flu)‐N‐heterocyclic carbene (NHC) ligand, [M{C2H4(η5‐Flu‐κ1‐NHC)}(CH2SiMe3)2] (M=Y, 1; Lu, 2), and a chiral ansa‐sandwich samarocene incorporating a C2 ligand, [Sm(η5‐C12H8)2(thf)2] (3), have been investigated for the coordination–addition polymerization of renewable methylene butyrolactones, α‐methylene‐γ‐butyrolactone (MBL) and γ‐methyl‐α‐methylene‐γ‐butyrolactone (γMMBL). Both ansa‐half‐sandwich complexes 1 and 2 exhibit exceptional activity for the polymerization of γMMBL at room temperature in dimethylformamide (DMF); with a 0.25 mol % catalyst loading, quantitative monomer conversion can be achieved under 1 min, giving a high turn‐over frequency (TOF) of 24 000 h−1. This TOF value represents a rate enhancement, by a factor of 8, 22, or 2400, over the polymerizations by unbridged samarocene [Sm(Cp*)2(thf)2] (Cp*=η5‐pentamethylcyclopentadienyl), by bridged ansa‐samarocene 3 with C2 ligation, or by the corresponding REM trialkyls without the ansa‐Flu‐NHC ligation, respectively. Complexes 1 and 2 are also highly active for the polymerization of β‐methyl‐α‐methylene‐γ‐butyrolactone (βMMBL), realizing the first example of the metal‐mediated coordination polymerization of this monomer and its copolymerization with γMMBL. More remarkably, the resulting PβMMBL homopolymer is highly stereoregular (91 % mm) and exhibits a high Tg of 290 °C. In sharp contrast, catalysts 1 and 2 have poor activity and efficiency in the polymerization of the parent MBL or the acyclic analog methyl methacrylate. Polymerization and kinetic studies using the most active catalyst (1) of the series have uncovered characteristics of its γMMBL polymerization and yielded a unimolecular propagation mechanism. A surprising chain‐initiation pathway for the polymerization in DMF by 1 has been revealed, and catalytic polymerization in the presence of an organoacid has also been examined.
Synthesis of Polycyclic Aromatic Hydrocarbon‐Based Nanovehicles Equipped with Triptycene Wheels
Authors: Jacquot de Rouville Henri‐Pierre , Garbage Romain , Cook Rita E. , Pujol Adeline R. , Sirven Agnès M. , Rapenne Gwénaël
Published: February 2012

Two new nanovehicles that have extended aromatic platforms as the cargo zones have been obtained. Two strategies were considered for the formation of the perylene core from two naphthalene precursors. The first was based on a Scholl‐type reaction involving an oxidant, and the second used a brominated derivative to perform a homocoupling reaction. The first strategy failed under diverse coupling conditions in the presence of several strong oxidants. Nevertheless, the use of CoF3 in trifluoroacetic acid triggered a dimerization reaction between two ester groups of one molecule and the naphthalene unit of another, thereby surprisingly yielding a ten‐membered carbon macrocycle. The second strategy encountered a lack of reactivity of the substrate under several homocoupling conditions. The dimerization was not easily performed but Ullmann‐type conditions ultimately gave the expected product. The low yield and low solubility of the product encouraged us to modify our initial design. The synthesis of a new chassis that incorporated additional tert‐butyl groups improved the solubility of the molecules and also prevented overcyclization of the aromatic platform by blocking these positions. Some p‐phenylene spacers were also intercalated between the iodine and perylene centers to increase the reactivity of the halide towards coupling reactions. Two new chassis were obtained by Scholl‐type oxidative coupling using FeCl3 as the oxidant. The introduction of four triptycene wheels allowed the formation of the two corresponding nanovehicles.
Conjugated Hyperbranched Poly(aryleneethynylene)s: Synthesis, Photophysical Properties, Superquenching by Explosive, Photopatternability, and Tunable High Refractive Indices
Authors: Yuan Wang Zhang , Hu Rongrong , Lam Jacky W. Y. , Xie Ni , Jim Cathy K. W. , Tang Ben Zhong
Published: February 2012

Triphenylamine (TPA)‐based conjugated hyperbranched poly(aryleneethynylene)s (PAEs), hb‐P1/2, hb‐P1/3, and hb‐P1/4, were synthesized with high molecular weights and good solubilities through Sonogashira coupling reactions. These PAEs exhibited outstanding thermal stabilities and different emission behaviors. Tetraphenylethene (TPE)‐containing hb‐P1/2 fluoresced faintly in THF, although its light emission was enhanced by aggregate formation in aqueous media or in thin films, thereby exhibiting an aggregation‐induced emission‐enhancement (AIEE) effect. Whereas 1,1,2,3,4,5‐hexaphenylsilole (HPS)‐bearing hb‐P1/3 showed no significant change in emission intensity with increasing water content in aqueous media, hb‐P1/4, which consisted of TPA–fluorenone donor–acceptor groups, presented almost identical absorptions, but both positive and negative solvatochromic emissions in various solvents. A superquenching effect was observed in the picric‐acid‐detection process by using nanosuspensions of hb‐P1/2. All of the polymers possessed good film formability. UV irradiation of the thin films induced simultaneous photobleaching and cross‐linking, thus making them applicable in the fabrication of 2D and 3D patterns. Furthermore, the polymer films also showed high refractive indices, which were tunable upon exposure to UV light.
Oligoether‐Strapped Calix[4]pyrrole: An Ion‐Pair Receptor Displaying Cation‐Dependent Chloride Anion Transport
Authors: Park In‐Won , Yoo Jaeduk , Kim Bohyang , Adhikari Suman , Kim Sung Kuk , Yeon Yerim , Haynes Cally J. E. , Sutton Jennifer L. , Tong Christine C. , Lynch Vincent M. , Sessler Jonathan L. , Gale Philip A. , Lee Chang‐Hee
Published: February 2012

A ditopic ion‐pair receptor (1), which has tunable cation‐ and anion‐binding sites, has been synthesized and characterized. Spectroscopic analyses provide support for the conclusion that receptor 1 binds fluoride and chloride anions strongly and forms stable 1:1 complexes ([1⋅F]− and [1⋅Cl]−) with appropriately chosen salts of these anions in acetonitrile. When the anion complexes of 1 were treated with alkali metal ions (Li+, Na+, K+, Cs+, as their perchlorate salts), ion‐dependent interactions were observed that were found to depend on both the choice of added cation and the initially complexed anion. In the case of [1⋅F]−, no appreciable interaction with the K+ ion was seen. On the other hand, when this complex was treated with Li+ or Na+ ions, decomplexation of the bound fluoride anion was observed. In contrast to what was seen with Li+, Na+, K+, treating [1⋅F]− with Cs+ ions gave rise to a stable, host‐separated ion‐pair complex, [F⋅1⋅Cs], which contains the Cs+ ion bound in the cup‐like portion of the calix[4]pyrrole. Different complexation behavior was seen in the case of the chloride complex, [1⋅Cl]−. Here, no appreciable interaction was observed with Na+ or K+. In contrast, treating with Li+ produces a tight ion‐pair complex, [1⋅Li⋅Cl], in which the cation is bound to the crown moiety. In analogy to what was seen for [1⋅F]−, treatment of [1⋅Cl]− with Cs+ ions gives rise to a host‐separated ion‐pair complex, [Cl⋅1⋅Cs], in which the cation is bound to the cup of the calix[4]pyrrole. As inferred from liposomal model membrane transport studies, system 1 can act as an effective carrier for several chloride anion salts of Group 1 cations, operating through both symport (chloride+cation co‐transport) and antiport (nitrate‐for‐chloride exchange) mechanisms. This transport behavior stands in contrast to what is seen for simple octamethylcalix[4]pyrrole, which acts as an effective carrier for cesium chloride but does not operates through a nitrate‐for‐chloride anion exchange mechanism.
Cooperative Catalytic Reactions Using Distinct Transition‐Metal Catalysts: Ruthenium‐ and Copper‐Catalyzed Enantioselective Propargylic Alkylation
Authors: Ikeda Masahiro , Miyake Yoshihiro , Nishibayashi Yoshiaki
Published: February 2012

The enantioselective propargylic alkylation of propargylic alcohols with β‐ketoesters in the presence of a thiolate‐bridged diruthenium complex and a copper complex as co‐catalyst affords the corresponding propargylic alkylated products in excellent yields as a mixture of two diastereoisomers with high enantioselectivity (up to 95 % enantiomeric excess (ee)). The findings reported herein not only open up a new type of enantioselective propargylic substitution reaction, but also a new aspect of cooperative catalytic reactions using distinct transition metals to realize a useful transformation that cannot be achieved by a single catalyst.