Functional Elastomers via Sequential Selective Diene Copolymerization/Hydrophosphorylation Catalysis

An effective preparation of new tailor‐made macromolecular materials via the combination of two fully atom‐efficient catalytic transformations is reported. First, new isoprene‐co‐1,3,7‐octatriene [P(IP‐co‐OT)] copolymers with controlled composition (2–21 mol% triene incorporated), molecular weight (M_n=23–102,000 g mol⁻¹) and microstructure (1,4‐cis rich) have been prepared using the homogeneous Ziegler–Natta catalyst system composed of diallylneodynium chloride, magnesium chloride, tetrahydrofuran and methylaluminoxane [Nd(allyl)₂Cl(MgCl₂)₂(THF)₄/MAO]. Next, the pendant vinyl moieties in those P(IP‐co‐OT) copolymers have been selectively transformed into phosphonate groups by hydrophosphorylation in the presence of homogeneous rhodium phosphine catalysts. The latter hydrophosphorylation reaction has been optimized in terms of catalytic activity and selectivity, to define the conditions for an effective and safe procedure that does not affect the macromolecular architecture. All polymer materials have been microstructurally analyzed by ¹H, ¹³C, and ³¹P NMR spectroscopy, to diagnose the catalyst selectivities in the copolymerization and hydrophosphorylation processes.     

An Empirical Study on the Generation Mechanism of NIMBY Conflicts of Construction Projects

In the highly overlapped contexts of urbanization and social transformation, and with the advent of the “Risk Society,” the social issues, called “Not in My Back Yard (NIMBY)” conflicts, caused by the construction or operation of the NIMBY projects have become a serious problem in China. Hence, it is in urgent need to find out the influencing factors and discover the generation mechanism of the NIMBY conflicts. From the perspective of social conflict theory, the authors built a process model of the NIMBY conflicts on the basis of identifying stakeholders and analyzing their interest interaction. Thereafter, the authors conducted a questionnaire survey, followed by exploratory factor analysis (EFA) revealing the underlying influencing factors of the NIMBY conflicts. Finally, they performed the confirmatory analysis method of Structural Equation Modeling to test the preliminary research hypothesis of the model and its interaction path in AMOS 18.0, with the results showing that unequal exchange and consensus mobilization will contribute to the formation of common consciousness of the opposition party, the opposition party’s common consciousness and action mobilization affects the generation of social conflicts. The process model reveals the generation mechanism of the NIMBY conflicts, and it facilitates further investigations in the governance of the NIMBY conflicts.     

Der Ausbau des Mittleren Rings Ost in München

Der Ausbau des Mittleren Rings Ost stellt eine bedeutende Infrastrukturmaßnahme für den Ostteil der Landeshauptstadt München dar, die vor allem auf die Verbesserung des Verkehrsflusses und die Reduktion der Schall‐ und Schadstoffimmissionen am hochbelasteten Mittleren Ring ausgerichtet ist. Auch weitreichende städtebauliche Maßnahmen können nach Abschluss der Tunnelbauarbeiten an der Oberfläche realisiert werden. Der Beitrag befasst sich sowohl mit dem Verkehrskonzept der Ausbaumaßnahme wie auch mit Bemessung, Konstruktion und Bauausführung der zugehörigen Tunnelbauwerke. Ein Schwerpunkt der Erläuterungen liegt dabei auf einem zweistöckigen Kreuzungsbauwerk, das wie alle anderen Tunnelbauwerke der Ausbaumaßnahme in Bohrpfahl‐Deckelbauweise hergestellt wurde. The MRO‐Tunnels in Munich. The construction of the MRO‐Tunnels in Munich represents an important infrastructural measure in the eastern part of the state capital Munich for traffic flow improvement, protection from noise and exhaust pollution as well as for the town development. The main aspects of this paper are the design and the computation of the MRO‐Tunnels with special focus on a complex tunnel crossing, which is located on Einsteinstrasse. The “Top‐Down” construction method was of substantial importance to maintain traffic flow and to extensively reduce impairment to adjacent buildings during the construction period.     

Controlling Electron and Hole Charge Injection in Ambipolar Organic Field‐Effect Transistors by Self‐Assembled Monolayers

Controlling contact resistance in organic field‐effect transistors (OFETs) is one of the major hurdles to achieve transistor scaling and dimensional reduction. In particular in the context of ambipolar and/or light‐emitting OFETs it is a difficult challenge to obtain efficient injection of both electrons and holes from one injecting electrode such as gold since organic semiconductors have intrinsically large band gaps resulting in significant injection barrier heights for at least one type of carrier. Here, systematic control of electron and hole contact resistance in poly(9,9‐di‐n‐octylfluorene‐alt‐benzothiadiazole) ambipolar OFETs using thiol‐based self‐assembled monolayers (SAMs) is demonstrated. In contrast to common believe, it is found that for a certain SAM the injection of both electrons and holes can be improved. This simultaneous enhancement of electron and hole injection cannot be explained by SAM‐induced work‐function modifications because the surface dipole induced by the SAM on the metal surface lowers the injection barrier only for one type of carrier, but increases it for the other. These investigations reveal that other key factors also affect contact resistance, including i) interfacial tunneling through the SAM, ii) SAM‐induced modifications of interface morphology, and iii) the interface electronic structure. Of particular importance for top‐gate OFET geometry is iv) the active polymer layer thickness that dominates the electrode/polymer contact resistance. Therefore, a consistent explanation of how SAM electrode modification is able to improve both electron and hole injection in ambipolar OFETs requires considering all mentioned factors.     

Altered DNA Methylation Profiles in SF3B1 Mutated CLL Patients

Mutations in splicing factor genes have a severe impact on the survival of cancer patients. Splicing factor 3b subunit 1 (SF3B1) is one of the most frequently mutated genes in chronic lymphocytic leukemia (CLL); patients carrying these mutations have a poor prognosis. Since the splicing machinery and the epigenome are closely interconnected, we investigated whether these alterations may affect the epigenomes of CLL patients. While an overall hypomethylation during CLL carcinogenesis has been observed, the interplay between the epigenetic stage of the originating B cells and SF3B1 mutations, and the subsequent effect of the mutations on methylation alterations in CLL, have not been investigated. We profiled the genome-wide DNA methylation patterns of 27 CLL patients with and without SF3B1 mutations and identified local decreases in methylation levels in SF3B1^mut CLL patients at 67 genomic regions, mostly in proximity to telomeric regions. These differentially methylated regions (DMRs) were enriched in gene bodies of cancer-related signaling genes, e.g., NOTCH1, HTRA3, and BCL9L. In our study, SF3B1 mutations exclusively emerged in two out of three epigenetic stages of the originating B cells. However, not all the DMRs could be associated with the methylation programming of B cells during development, suggesting that mutations in SF3B1 cause additional epigenetic aberrations during carcinogenesis.     

Proteins Binding to the Carbohydrate HNK-1: Common Origins?

The human natural killer (HNK-1) carbohydrate plays important roles during nervous system development, regeneration after trauma and synaptic plasticity. Four proteins have been identified as receptors for HNK-1: the laminin adhesion molecule, high-mobility group box 1 and 2 (also called amphoterin) and cadherin 2 (also called N-cadherin). Because of HNK-1′s importance, we asked whether additional receptors for HNK-1 exist and whether the four identified proteins share any similarity in their primary structures. A set of 40,000 sequences homologous to the known HNK-1 receptors was selected and used for large-scale sequence alignments and motif searches. Although there are conserved regions and highly conserved sites within each of these protein families, there was no sequence similarity or conserved sequence motifs found to be shared by all families. Since HNK-1 receptors have not been compared regarding binding constants and since it is not known whether the sulfated or non-sulfated part of HKN-1 represents the structurally crucial ligand, the receptors are more heterogeneous in primary structure than anticipated, possibly involving different receptor or ligand regions. We thus conclude that the primary protein structure may not be the sole determinant for a bona fide HNK-1 receptor, rendering receptor structure more complex than originally assumed.     

Measurement of DDT fluxes from a historically treated agricultural soil in Canada

Organocohlorine pesticide (OCP) residues in agricultural soils are of concern due to the uptake of these compounds by crops, accumulation in the foodchain, and reemission from soils to the atmosphere. Although it has been about three decades since DDT was banned for agricultural uses in Canada, residues persist in soils of some agricultural areas. Emission of DDT compounds to the atmosphere from a historically treated field in southern Ontario was determined in fall 2004 and spring 2005. The sigmaDDTs concentration in the high organic matter (71%) soil was 19 +/- 4 microg g(-1) dry weight. Concentration gradients in the air were measured at 5, 20, 72, and 200 cm above soil using glass fiber filter-polyurethane foam cartridges. Air concentrations of sigmaDDTs averaged 5.7 +/- 5.1 ng m(-3) at 5 cm and decreased to 1.3 +/- 0.8 ng m(-3) at 200 cm and were 60-300 times higher than levels measured at a background site 30 km away. Soil-air fugacity fractions, fs/(fs + fa), of p,p'-DDE, p,p'-DDD, and p,p'-DDT ranged from 0.42 to 0.91 using air concentrations measured above the soil and > or = 0.99 using background air concentrations, indicating that the soil was a net source to the background air. Fractionation of DDT compounds during volatilization was predicted using either liquid-phase vapor pressures (PL) or octanol-air partition coefficients (KOA). Relative emissions of p,p'-DDE and p,p'-DDT were better described by PL than KOA, whereas either PL or KOA successfully accounted for the fractionation of p,p'-DDT and o,p'-DDT. Soil-to-air fluxes were calculated from air concentration gradients and turbulent exchange coefficients determined from micrometeorological measurements. Average fluxes of sigmaDDTs were 90 +/- 24 ng m(-2) h(-1) in fall and 660 +/- 370 ng m(-2) h(-1) in spring. Higher soil temperatures in spring accounted for the higher fluxes. A volatilization half-life of approximately 200 y was estimated for sigmaDDT in the upper 5 cm of the soil column, assuming the average flux rate for 12 h d-(1) over 8 months of the year. Thus, in the absence of other dissipation processes, the soil will continue to be a source of atmospheric contamination for a very long time.     

ESMRMB 2009 Congress,Antalya, Turkey, 1–3 October: Abstracts,Thursday

Object  To determine whether glycine can be measured at 7 T in human brain with ¹H magnetic resonance spectroscopy (MRS). Materials and methods  The glycine singlet is overlapped by the larger signal of myo-inositol. Density matrix simulations were performed to determine the TE at which the myo-inositol signal was reduced the most, following a single spin-echo excitation. ¹H MRS was performed on an actively shielded 7 T scanner, in five healthy volunteers. Results  At the TE of 30 ms, the myo-inositol signal intensity was substantially reduced. Quantification using LCModel yielded a glycine-to-creatine ratio of 0.14 ± 0.01, with a Cramér–Rao lower bound (CRLB) of 7 ± 1%. Furthermore, quantification of metabolites other than glycine was possible as well, with a CRLB mostly below 10%. Conclusion  It is possible to detect glycine at 7 T in human brain, at the short TE of 30 ms with a single spin-echo excitation scheme.