The metallic state in disordered quasi-one-dimensional conductors

The unusual metallic state in conjugated polymers and single-walled carbon nanotubes is studied by dielectric spectroscopy (8--600 GHz). We have found an intriguing correlation between scattering time and plasma frequency. This relation excludes percolation models of the metallic state. Instead, the carrier dynamics can be understood in terms of the low density of delocalized states around the Fermi level, which arises from the competion between disorder-induced localization and interchain-interactions-induced delocalization.Comment: 4 pages including 4 figure

The non-coordinating anion 1,1,3,3-tetracyano-2-propoxy-propenide as an anion-pi donor in cis-diaquabis(2,2 '-dipyridylamine)zinc and its cadmium analog: Luminescence properties, Hirshfeld analysis and central-atom induced polymorphism

Metals in Catalysis, Biomimetics & Inorganic Material

Dopant-induced crossover from 1D to 3D charge transport in conjugated polymers

The interplay between inter- and intra-chain charge transport in bulk polythiophene in the hopping regime has been clarified by studying the conductivity as a function of frequency (up to 3 THz), temperature and doping level. We present a model which quantitatively explains the observed crossover from quasi-one-dimensional transport to three-dimensional hopping conduction with increasing doping level. At high frequencies the conductivity is dominated by charge transport on one-dimensional conducting chains.Comment: 4 pages, 2 figure

Characteristics and outcome in patients with central nervous system involvement treated in European pediatric acute myeloid leukemia study groups

Background: There is no consensus on the treatment for pediatric patients with acute myeloid leukemia and initial central nervous system (CNS) involvement. Methods: To evaluate different CNS-directed treatment options (intrathecal [IT] therapy, CNS irradiation, hematopoietic stem cell transplantation [HSCT]), 261 patients (excluding acute promyelocytic leukemia) with initial CNS involvement treated in trials with similar intensive chemotherapy by four cooperative European study groups (1998–2013) were studied and compared with CNS-negative patients from the Berlin–Frankfurt–Münster group. Results: Patient characteristics in the different study groups were comparable. Young age, high white blood cell count, extramedullary involvement other than the CNS, monoblastic morphology, and inv(16) were associated with CNS involvement (each P < 0.0001). There were no major differences in outcome between the study groups. The cumulative incidence of relapse (CIR) regarding the CNS was higher in initially CNS-positive versus initially CNS-negative patients (all: 8 ± 2% vs. 3 ± 1%, P(Gray) = 0.001; isolated: 4 ± 1% vs. 1 ± 0%, P(Gray) = 0.03). However, global outcome of the CNS-positive cohort (overall survival, 64 ± 3%; event-free survival 48 ± 3%; and CIR 33% ± 3%) did not differ significantly from CNS-negative patients. Risk groups defined by cytogenetics were of likewise prognostic significance in CNS-positive and -negative patients. CNS treatment with cranial irradiation was not superior compared to IT therapy and systemic chemotherapy (± HSCT). Conclusion: Although CNS relapses occurred more frequently in initially CNS-positive patients, their global outcome was similar as in CNS-negative patients. Intensified IT therapy was heterogeneous; however, at least eight applications, preferably with triple IT chemotherapy, seem to be appropriate to accompany dose-intensive systemic chemotherapy

Synthesis, structure and luminescence properties of zinc and cadmium linear-chain compounds with anionic monoalkoxy-tetracyanopropenes bridged by 4,4 '-bipyridines

The synthesis, characterization and 3D structure determination of Zinc and Cadmium compounds are reported, containing the non-chelating bidentate ligand 4,4'-bipyridine and the anions 1,1,3,3-tetracyano-2-propoxy-propenide (tcnopr) or 1,1,3,3-tetracyano-2-ethoxy-propenide (tcnoet). The structures consist of linear chains (1D) built from metal ions and 4,4'-bipyridine, where the octahedral coordination around the metals is completed by two trans anions tcnoet (or tcnopr), and two trans-oriented water molecules. Weak interchain interactions are present, based on hydrogen bonds between the water ligands (both hydrogens are involved) and two CN groups of two nearby other chains. Metal-ligand distances appear as uneventful. For the same anion, the Zn and Cd compounds are isomorphous. Possible decomposition of the compounds has been investigated in the temperature range 30-800 degrees C in a static air atmosphere. Thermal analysis studies (TG, DTG, DTA) show that the axial water ligands for all three compounds are gradually lost upon heating above 60 degrees C to about 170 degrees C. Luminescence properties, recorded as powders, are reported as well, and these appear as strong for the Cd compound I, when irradiated at 390 nm, extremely weak for the Cd compound II, when irradiated at wavelengths from 300-400 nm, and moderately weak for the Zn compound III when irradiated at 385 nm. (C) 2019 The Author(s). Published by Elsevier Ltd.Metals in Catalysis, Biomimetics & Inorganic Material

Density Distribution in the Liquid Hg-Sapphire Interface

We present the results of a computer simulation study of the liquid density distribution normal to the interface between liquid Hg and the reconstructed (0001) face of sapphire. The simulations are based on an extension of the self-consistent quantum Monte Carlo scheme previously used to study the structure of the liquid metal-vapor interface. The calculated density distribution is in very good agreement with that inferred from the recent experimental data of Tamam et al (J. Phys. Chem. Lett. 1, 1041-1045 (2010)). We conclude that, to account for the difference in structure between the liquid Hg-vapor and liquid-Hg-reconstructed (0001) Al2O3 interfaces, it is not necessary assume there is charge transfer from the Hg to the Al2O3. Rather, the available experimental data are adequately reproduced when the van der Waals interactions of the Al and O atoms with Hg atoms and the exclusion of electron density from Al2O3 via repulsion of the electrons from the closed shells of the ions in the solid are accounted for.Comment: 26 pages, 11 figure

Impact Factor: outdated artefact or stepping-stone to journal certification?

A review of Garfield's journal impact factor and its specific implementation as the Thomson Reuters Impact Factor reveals several weaknesses in this commonly-used indicator of journal standing. Key limitations include the mismatch between citing and cited documents, the deceptive display of three decimals that belies the real precision, and the absence of confidence intervals. These are minor issues that are easily amended and should be corrected, but more substantive improvements are needed. There are indications that the scientific community seeks and needs better certification of journal procedures to improve the quality of published science. Comprehensive certification of editorial and review procedures could help ensure adequate procedures to detect duplicate and fraudulent submissions.Comment: 25 pages, 12 figures, 6 table

The Role of Atypical Protein Kinase C in CSF-1-Dependent Erk Activation and Proliferation in Myeloid Progenitors and Macrophages

Colony stimulating factor-1 (CSF-1 or M-CSF) is the major physiological regulator of the proliferation, differentiation and survival of cells of the mononuclear phagocyte lineage. CSF-1 binds to a receptor tyrosine kinase, the CSF-1 receptor (CSF-1R). Multiple pathways are activated downstream of the CSF-1R; however, it is not clear which pathways regulate proliferation and survival. Here, we investigated the role of atypical protein kinase Cs (PKCζ) in a myeloid progenitor cell line that expressed CSF-1R (32D.R) and in primary murine bone marrow derived macrophages (BMMs). In 32D.R cells, CSF-1 induced the phosphorylation of PKCζ and increased its kinase activity. PKC inhibitors and transfections with mutant PKCs showed that optimal CSF-1-dependent Erk activation and proliferation depended on the activity of PKCζ. We previously reported that CSF-1 activated the Erk pathway through an A-Raf-dependent and an A-Raf independent pathway (Lee and States, Mol. Cell. Biol. 18, 6779). PKC inhibitors did not affect CSF-1 induced Ras and A-Raf activity but markedly reduced MEK and Erk activity, implying that PKCζ regulated the CSF-1-Erk pathway at the level of MEK. PKCζ has been implicated in activating the NF-κB pathway. However, CSF-1 promoted proliferation in an NF-κB independent manner. We established stable 32D.R cell lines that overexpressed PKCζ. Overexpression of PKCζ increased the intensity and duration of CSF-1 induced Erk activity and rendered cells more responsive to CSF-1 mediated proliferation. In contrast to 32D.R cells, PKCζ inhibition in BMMs had only a modest effect on proliferation. Moreover, PKCζ -specific and pan-PKC inhibitors induced a paradoxical increase in MEK-Erk phosphorylation suggesting that PKCs targeted a common negative regulatory step upstream of MEK. Our results demonstrated that CSF-1 dependent Erk activation and proliferation are regulated differentially in progenitors and differentiated cells

Key signalling nodes in mammary gland development and cancer: Myc

Myc has been intensely studied since its discovery more than 25 years ago. Insight has been gained into Myc's function in normal physiology, where its role appears to be organ specific, and in cancer where many mechanisms contribute to aberrant Myc expression. Numerous signals and pathways converge on Myc, which in turn acts on a continuously growing number of identified targets, via transcriptional and nontranscriptional mechanisms. This review will concentrate on Myc as a signaling mediator in the mammary gland, discussing its regulation and function during normal development, as well as its activation and roles in breast cancer