Reactivity of [Cp′′ 2 Zr(η 1:1 −E 4 )] (E=P, As) towards Nucleophiles

The functionalization of the polypnictogen ligand complexes [Cp′′2Zr(η1:1-E4)] (E=P (1 a), As (1 b); Cp′′=1,3-di-tertbutyl-cyclopentadienyl) is focused to modify the features of the polypnictogen unit to explore new synthetic pathways for further transformations. The reaction behavior of 1 towards main group nucleophiles is investigated. The reaction of 1 a with tBuLi leads to the ionic product Li[Cp′′2Zr(η1:1-P4tBu)] (2) where an organic group is attached to a bridgehead phosphorus atom of the butterfly unit. Further reactions of 2 with quenching electrophilic reagents enable the introduction of other substituents. Moreover, a condensation of 2 to [(Cp′′2Zr)2(μ,η1:1:1:1-P8tBu2)] (3), containing a novel P8-unit, has been observed. The reaction of 1 with LiNMe2 and LiCH2SiMe3 leads to a partial fragmentation of the E4 unit and the compounds [Cp′′2Zr(η2-E3Nu)] (Nu=NMe2: E=P (6 a), As (6 b); Nu=CH2SiMe3: E=P (7 a), As (7 b)) are formed

Fetal eye movements on magnetic resonance imaging.

OBJECTIVES: Eye movements are the physical expression of upper fetal brainstem function. Our aim was to identify and differentiate specific types of fetal eye movement patterns using dynamic MRI sequences. Their occurrence as well as the presence of conjugated eyeball motion and consistently parallel eyeball position was systematically analyzed. METHODS: Dynamic SSFP sequences were acquired in 72 singleton fetuses (17-40 GW, three age groups [17-23 GW, 24-32 GW, 33-40 GW]). Fetal eye movements were evaluated according to a modified classification originally published by Birnholz (1981): Type 0: no eye movements; Type I: single transient deviations; Type Ia: fast deviation, slower reposition; Type Ib: fast deviation, fast reposition; Type II: single prolonged eye movements; Type III: complex sequences; and Type IV: nystagmoid. RESULTS: In 95.8% of fetuses, the evaluation of eye movements was possible using MRI, with a mean acquisition time of 70 seconds. Due to head motion, 4.2% of the fetuses and 20.1% of all dynamic SSFP sequences were excluded. Eye movements were observed in 45 fetuses (65.2%). Significant differences between the age groups were found for Type I (p = 0.03), Type Ia (p = 0.031), and Type IV eye movements (p = 0.033). Consistently parallel bulbs were found in 27.3-45%. CONCLUSIONS: In human fetuses, different eye movement patterns can be identified and described by MRI in utero. In addition to the originally classified eye movement patterns, a novel subtype has been observed, which apparently characterizes an important step in fetal brainstem development. We evaluated, for the first time, eyeball position in fetuses. Ultimately, the assessment of fetal eye movements by MRI yields the potential to identify early signs of brainstem dysfunction, as encountered in brain malformations such as Chiari II or molar tooth malformations

MR-based morphometry of the posterior fossa in fetuses with neural tube defects of the spine.

OBJECTIVES: In cases of "spina bifida," a detailed prenatal imaging assessment of the exact morphology of neural tube defects (NTD) is often limited. Due to the diverse clinical prognosis and prenatal treatment options, imaging parameters that support the prenatal differentiation between open and closed neural tube defects (ONTDs and CNTDs) are required. This fetal MR study aims to evaluate the clivus-supraocciput angle (CSA) and the maximum transverse diameter of the posterior fossa (TDPF) as morphometric parameters to aid in the reliable diagnosis of either ONTDs or CNTDs. METHODS: The TDPF and the CSA of 238 fetuses (20-37 GW, mean: 28.36 GW) with a normal central nervous system, 44 with ONTDS, and 13 with CNTDs (18-37 GW, mean: 24.3 GW) were retrospectively measured using T2-weighted 1.5 Tesla MR -sequences. RESULTS: Normal fetuses showed a significant increase in the TDPF (r = .956; p<.001) and CSA (r = .714; p<.001) with gestational age. In ONTDs the CSA was significantly smaller (p<.001) than in normal controls and CNTDs, whereas in CNTDs the CSA was not significantly smaller than in controls (p = .160). In both ONTDs and in CNTDs the TDPF was significantly different from controls (p<.001). CONCLUSIONS: The skull base morphology in fetuses with ONTDs differs significantly from cases with CNTDs and normal controls. This is the first study to show that the CSA changes during gestation and that it is a reliable imaging biomarker to distinguish between ONTDs and CNTDs, independent of the morphology of the spinal defect

E 4 Transfer (E=P, As) to Ni Complexes

The use of [Cp′′2Zr(η1:1-E4)] (E=P (1 a), As (1 b), Cp′′=1,3-di-tert-butyl-cyclopentadienyl) as phosphorus or arsenic source, respectively, gives access to novel stable polypnictogen transition metal complexes at ambient temperatures. The reaction of 1 a/1 b with [CpRNiBr]2 (CpR=CpBn (1,2,3,4,5-pentabenzyl-cyclopentadienyl), Cp′′′ (1,2,4-tri-tert-butyl-cyclopentadienyl)) was studied, to yield novel complexes depending on steric effects and stoichiometric ratios. Besides the transfer of the complete En unit, a degradation as well as aggregation can be observed. Thus, the prismane derivatives [(Cp′′′Ni)2(μ,η3:3-E4)] (2 a (E=P); 2 b (E=As)) or the arsenic containing cubane [(Cp′′′Ni)3(μ3-As)(As4)] (5) are formed. Furthermore, the bromine bridged cubanes of the type [(CpRNi)3{Ni(μ-Br)}(μ3-E)4]2 (CpR=Cp′′′: 6 a (E=P), 6 b (E=As), CpR=CpBn: 8 a (E=P), 8 b (E=As)) can be isolated. Here, a stepwise transfer of En units is possible, with a cyclo-E42− ligand being introduced and unprecedented triple-decker compounds of the type [{(CpRNi)3Ni(μ3-E)4}2(μ,η4:4-E′4)] (CpR=CpBn, Cp′′′; E/E′=P, As) are obtained

Influence of Canopy Disturbances on Runoff and Landslide Disposition after Heavy Rainfall Events

As protective forests have a major control function on runoff and erosion, they directly affect the risk from hydrogeomorphic processes such as sediment transport processes or debris flows. In this context, future scenarios of climate-related canopy disturbances and their influence on the protective effect remain, however, an unsolved problem. With the individual-based forest landscape and disturbance model iLand, an ensemble of forest landscape simulations was carried out and the effects of future changes in natural disturbance regimes were evaluated. To determine peak runoff, hydrological simulations have been conducted, using the conceptual hydrological model ZEMOKOST as well as the deterministic model GEOtop. Effects of forest disturbances on hillslope stability were investigated, based on a modified Coulomb landslide model. Our results suggest no influence of the disturbance regime on the runoff. The climate-related increase in the frequency of disturbances is not reflected in increased runoff during the period under consideration. Contrary, slope stability analyses indicate that the availability of shallow landslides in steep forested torrent catchments might be decreased by the occurrence of disturbances – especially for a warm and dry climate projection. Canopy disturbances seem to accelerate the adaptation of tree species to future climate conditions, which is likely to be accompanied by a change in root systems away from flat roots that currently predominate in torrential catchments. In terms of managing the protective effect of forests against shallow landslides, such natural disturbances can thus be considered as positive interventions in the existing forest ecosystem by promoting natural succession

Die Bewerbung und Glaubwürdigkeit des Umweltschutzes auf Webseiten ausgewählter Tiroler Hotels

Veronika SeidlUniversität Innsbruck, Masterarbeit, 2017(VLID)187454

Synthesis of polyantimony ligand complexes starting from Cp*4Sb4

The reactivity of Cp*Sb-4(4) (1) towards ionic compounds and transition metal complexes with labile ligands was investigated in order to synthesize polyantimony ligand complexes. The silver salts [Ag][X] and the metalate Na[Cp*Mo(CO)(3)] were primarily used, leading in the raction with Cp*Sb-4(4) to the formation of [Cp*Sb-2][X] (X = TEF (2a), FAL (2b)), [(Cp*Mo(CO)(3))(3)(mu(3)-Sb-3)] (3) and [Cp*Mo(CO)(2)(eta(3)-Sb-3)] (4), respectively. The reaction of 1 with the transition metal complexes [(Cp ''' M)(2)(tol)] leads to a degradation of the original Sb-4 unit and to the formation of [(Cp ''' M)(4)(mu(3)-Sb)(4)] (M = Ni (5); Co (6)). Towards [(CpFe)-Fe-R(CO)(2)](2), substitutions on the antimony atoms were observed to give [{(CpFe)-Fe-R(CO)(2)}(4)(mu(4)-Sb-4)] (Cp-R = Cp '' (7a), Cp ''' (7b)). All complexes were characterized by XRD and spectroscopic methods

Luhmann's Systems Theory and Network Theory

Bommes M, Tacke V. Luhmann's Systems Theory and Network Theory. In: Seidl D, Becker KH, eds. Niklas Luhmann and Organization Studies. Advances in organization studies. Vol 14. Copenhagen: Liber &amp; Copenhagen Business School Press; 2005: 282-304

Transfer of polyantimony units

Transfer reagents are useful tools in chemistry to access metastable compounds. The reaction of [Cp '' 2ZrCl2] with KSb(SiMe3)(2) leads to the formation of the novel polyantimony triple decker complex [(Cp '' Zr)(2)(mu,eta(1:1:1:1:1:1)-Sb-6)] (1, Cp '' = 1,3-di-tertbutyl-cyclopentadienyl), containing a chair-like Sb-6(6-) ligand. Compound 1 represents a valuable transfer reagent to form novel antimony ligand complexes. Thus, the reaction of 1 with Cp(R)-substituted transition metal halides of nickel, cobalt and iron leads to the formation of a variety of novel Sb-n ligand complexes, such as the cubane-like compounds [(Cp ''' Ni)(4)(mu(3)-Sb)(4)] (2) and [(Cp ''' Co)(4)(mu(3)-Sb-4)] (3a) or the complexes [((CpCo)-Co-Bn)(3)(mu(3)-Sb)(2)] (4) and [(Cp ''' Fe)(3)(mu(3)-Sb)(2)] (5), representing a trigonal bipyramidal structure. Moreover, beside the transfer of Sb-1 units, also the complete entity can be transferred as seen in the iron complex [(Cp ''' Fe)(3)(mu(3,)eta(4:4:4)-Sb-6)] (6). DFT calculations shed light on the bonding situation of the products

CERAMIC 3D PRINTING: COMPARISON OF SLA AND DLP TECHNOLOGIES

Complex ceramic parts tend to be difficult or even impossible to produce by conventional methods. Therefore, the 3D printing technologies have started to spread widely in the area of ceramic parts production. The aim of this paper is to compare the efficiency of Stereolithography and Digital Light Processing technologies in 3D printing of ceramic parts. Firstly, indicative chemical analysis was performed on a chosen ceramic suspension. Secondly, sample parts of different shapes were designed and printed using both technologies. Next, printed samples were analyzed using thermogravimetric and optical analyses. Finally, printed parts were debound and sintered, and final ceramic parts were consequently reanalyzed. Both technologies show the best results in the printing of thin-walled and hollow models. The DLP was significantly faster, especially when the printing platform was close to full occupancy