High-performance nn-type organic field-effect transistors with ionic liquid gates

High-performance $n$-type organic field-effect transistors were developed with ionic-liquid gates and N,N$^"$-bis(n-alkyl)-(1,7 and 1,6)-dicyanoperylene-3,4:9,10-bis(dicarboximide)s single-crystals. Transport measurements show that these devices reproducibly operate in ambient atmosphere with negligible gate threshold voltage and mobility values as high as 5.0 cm$^2$/Vs. These mobility values are essentially identical to those measured in the same devices without the ionic liquid, using vacuum or air as the gate dielectric. Our results indicate that the ionic-liquid and $n$-type organic semiconductor interfaces are suitable to realize high-quality $n$-type organic transistors operating at small gate voltage, without sacrificing electron mobility

Single-Crystal Organic Charge-Transfer Interfaces probed using Schottky-Gated Heterostructures

Organic semiconductors based on small conjugated molecules generally behave as insulators when undoped, but the hetero-interfaces of two such materials can show electrical conductivity as large as in a metal. Although charge transfer is commonly invoked to explain the phenomenon, the details of the process and the nature of the interfacial charge carriers remain largely unexplored. Here we use Schottky-gated heterostructures to probe the conducting layer at the interface between rubrene and PDIF-CN2 single crystals. Gate-modulated conductivity measurements demonstrate that interfacial transport is due to electrons, whose mobility exhibits band-like behavior from room temperature to ~ 150 K, and remains as high as ~ 1 cm2V-1s-1 at 30 K for the best devices. The electron density decreases linearly with decreasing temperature, an observation that can be explained quantitatively based on the heterostructure band diagram. These results elucidate the electronic structure of rubrene-PDIF-CN2 interfaces and show the potential of Schottky-gated organic heterostructures for the investigation of transport in molecular semiconductors.Comment: 37 pages, 9 Figures (including supplementary information

Trafficking properties of plasmacytoid dendritic cells in health and disease.

Plasmacytoid dendritic cells (PDCs) represent a subset of circulating leukocytes characterized by the ability to release high levels of type I interferon (IFN). Under homeostatic conditions PDCs are confined to primary and secondary lymphoid organs. This is consistent with the restricted profile of functional chemotactic receptors expressed by circulating PDCs (i.e. CXCR4 and ChemR23). Accumulation of PDCs in non-lymphoid tissue is, however, observed in certain autoimmune diseases, allergic reactions and tumors. Indeed, PDCs are now considered to be involved in the pathogenesis of diseases characterized by a type I IFN-signature and are considered as a promising target for new intervention strategies. Here, current knowledge of the molecular mechanisms involved in the recruitment of PDCs under homeostatic and pathological conditions are summarized

Very low bias stress in n-type organic single crystal transistors

Bias stress effects in n-channel organic field-effect transistors (OFETs) are investigated using PDIF-CN2 single-crystal devices with Cytop gate dielectric, both under vacuum and in ambient. We find that the amount of bias stress is very small as compared to all (p-channel) OFETs reported in the literature. Stressing the PDIF-CN2 devices by applying 80 V to the gate for up to a week results in a decrease of the source drain current of only ~1% under vacuum and ~10% in air. This remarkable stability of the devices leads to characteristic time constants, extracted by fitting the data with a stretched exponential - that are \tau ~ 2\cdot10^9 s in air and \tau ~ 5\cdot10^9 s in vacuum - approximately two orders of magnitude larger than the best values reported previously for p-channel OFETs.Comment: Submitted to Applied Physics Letters; 14 pages, 3 figure

Antiproliferative effects of chalcones on T cell acute lymphoblastic leukemia‐derived cells: Role of PKCβ

In this study, a series of 20 chalcone derivatives was synthesized, and their antiproliferative activity was tested against the human T cell acute lymphoblastic leukemia\u2010derived cell line, CCRF\u2010CEM. On the basis of the structural features of the most active compounds, a new library of chalcone derivatives, according to the structure\u2013activity relationship design, was synthesized, and their antiproliferative activity was tested against the same cancer cell line. Furthermore, four of these derivatives (compounds 3, 4, 8, 28), based on lower IC50 values (between 6.1 and 8.9 \u3bcM), were selected for further investigation regarding the modulation of the protein expression of RACK1 (receptor for activated C kinase), protein kinase C (PKC)\u3b1 and PKC\u3b2, and their action on the cell cycle level. The cell cycle analysis indicated a block in the G0/G1 phase for all four compounds, with a statistically significant decrease in the percentage of cells in the S phase, with no indication of apoptosis (sub\u2010G0/G1 phase). Compounds 4 and 8 showed a statistically significant reduction in the expression of PKC\u3b1 and an increase in PKC\u3b2, which together with the demonstration of an antiproliferative role of PKC\u3b2, as assessed by treating cells with a selective PKC\u3b2 activator, indicated that the observed antiproliferative effect is likely to be mediated through PKC\u3b2 induction

A practical algorithmic approach to mature aggressive B cell lymphoma diagnosis in the double/triple hit era. Selecting cases, matching clinical benefit. A position paper from the Italian Group of Haematopathology (G.I.E.)

An accurate diagnosis of clinically distinct subgroups of aggressive mature B cell lymphomas is crucial for the choice of proper treatment. Presently, precise recognition of these disorders relies on the combination of morphological, immunophenotypical, and cytogenetic/molecular features. The diagnostic workup in such situations implies the application of costly and time-consuming analyses, which are not always required, since an intensified treatment option is reasonably reserved to fit patients. The Italian Group of Haematopathology proposes herein a practical algorithm for the diagnosis of aggressive mature B cell lymphomas based on a stepwise approach, aimed to select cases deserving molecular analysis, in order to optimize time and resources still assuring the optimal management for any patient

Isomeric carbazolocarbazoles: synthesis, characterization and comparative study in Organic Field Effect Transistors

We report here the synthesis and characterization of a new family of isomeric carbazolocarbazole derivatives, namely carbazolo[1,2-a]carbazole, carbazolo[3,2-b]carbazoleand carbazolo[4,3-c]carbazole. Thermal, optical, electrochemical, morphological and semiconducting properties have been studied to understand the influence of geometrical isomerism on the optoelectronic properties of these compounds. Different packing patterns have been observed by single crystal X-ray diffraction (XRD) which then correlate with the different morphologies of the evaporated thin films studied by XRD and Atomic Force Microscopy (AFM). The effect of N-substituents has also been evaluated for one of the isomers revealing a noticeable influence on the performance as organic semiconductors in Organic Field Effect Transistors (OFETs). A good p-channel field effect has been determined for N,N′-dioctylcarbazolo[4,3-c]carbazole with a mobility of 0.02 cm2 V−1 s−1 and Ion/Ioff ratio of 106 in air. These preliminary results demonstrate the promising properties of molecular carbazolocarbazole systems which should be further explored in the area of organic semiconducting materials

Tailoring the molecular structure to suppress extrinsic disorder in organic transistors

In organic field-effect transistors, the structure of the constituent molecules can be tailored to minimize the disorder experienced by charge carriers. Experiments on two perylene derivatives show that disorder can be suppressed by attaching longer core substituents - thereby reducing potential fluctuations in the transistor channel and increasing the mobility at low temperature - without altering the intrinsic transport properties

European consensus on grading bone marrow fibrosis and assessment of cellularity

Quantification of characteristic bone marrow biopsy features includes basic parameters such as cellularity and fiber content. These are important to assess the dynamics of disease processes with a significant impact on risk stratification, survival patterns and, especially, therapy-related changes. A panel of experienced European pathologists and a foreign expert evaluated, at a multi-headed microscope, a large number of representative slides of trephine biopsies from patients with myelofibrosis in an attempt to reach a consensus on how to grade cellularity and fibrosis. This included a critical evaluation of previously described scoring systems. During the microscopic analysis and subsequent discussion and voting, the importance of age-dependent decrease in cellularity was recognized. Grading of myelofibrosis was simplified by using four easily reproducible categories including differentiation between reticulin and collagen. A consensus was reached that the density of fibers must be assessed in relation to the hematopoietic tissue. This feature is especially important in order to avoid a false impression of a reduced fiber content in fatty and/or edematous bone marrow samples after treatment. The consensus for measuring myelofibrosis by clear and reproducible guidelines achieved by our group should allow for precise grading during the disease process and after therapy