Hybrid Organosulfur Network/MWCNT Composite Cathodes for Li-S Batteries

Lithium-sulfur (Li-S) batteries hold a promising position as candidates for next-generation high-energy storage systems. Here, we combine inverse vulcanization of sulfur with multiwalled carbon nanotubes (MWCNTs) to increase the conductivity of cathode materials for Li-S batteries. The mixing process of inversely vulcanized sulfur copolymer networks with MWCNTs is aided by shear in a two-roll mill to take advantage of the soft nature of the copolymer. The high-throughput mixing method demands a source of conductive carbon that can be intimately mixed with the S copolymer, rendering MWCNTs an excellent choice for this purpose. The resulting sulfur copolymer network-MWCNTs composites were thoroughly characterized in terms of structure, chemical composition, thermal, and electronic transport properties, and finally evaluated by electrochemical benchmarking. These promising hybrids yielded electrodes with high sulfur content and demonstrate stable electrochemical performance exhibiting a specific capacity of ca. 550 mAh·gsulfur-1 (380 mAh·gelectrode-1) even after 500 charge-discharge cycles at specific current of 167 mA·g-1 (corresponds to 0.1C discharge rate), and thus are superior to melt-infiltrated reference samples.

Roles of perception of similarities, continuum beliefs, and social distance toward a person with schizophrenia: a German sample study

Continuum beliefs (CB) interventions aim to reduce the stigma of schizophrenia by stating that people with and without schizophrenia exist on one mental health-illness continuum. The current study examines the interrelation between perception of similarities (PoS), CB and desire for social distance (SD) in a German population sample (N = 760). Applying linear regression models: PoS and CB were significantly associated with lower SD explaining about 12% variance and PoS was significantly associated with higher CB. CB partially mediated the relation of PoS and SD. Upcoming mental illness stigma interventions applying CB interventions should also aim to increase PoS.

Exploring the Druggability of Conserved RNA Regulatory Elements in the SARS-CoV-2 Genome

SARS-CoV-2 contains a positive single-stranded RNA genome of approximately 30 000 nucleotides. Within this genome, 15 RNA elements were identified as conserved between SARS-CoV and SARS-CoV-2. By nuclear magnetic resonance (NMR) spectroscopy, we previously determined that these elements fold independently, in line with data from in vivo and ex-vivo structural probing experiments. These elements contain non-base-paired regions that potentially harbor ligand-binding pockets. Here, we performed an NMR-based screening of a poised fragment library of 768 compounds for binding to these RNAs, employing three different 1 H-based 1D NMR binding assays. The screening identified common as well as RNA-element specific hits. The results allow selection of the most promising of the 15 RNA elements as putative drug targets. Based on the identified hits, we derive key functional units and groups in ligands for effective targeting of the RNA of SARS-CoV-2.

Vertical organic permeable dual-base transistors for logic circuits

The main advantage of organic transistors with dual gates/bases is that the threshold voltages can be set as a function of the applied second gate/base bias, which is crucial for the application in logic gates and integrated circuits. However, incorporating a dual gate/base structure into an ultra-short channel vertical architecture represents a substantial challenge. Here, we realize a device concept of vertical organic permeable dual-base transistors, where the dual base electrodes can be used to tune the threshold voltages and change the on-currents. The detailed operation mechanisms are investigated by calibrated TCAD simulations. Finally, power-efficient logic circuits, e.g. inverter, NAND/AND computation functions are demonstrated with one single device operating at supply voltages of <2.0 V. We believe that this work offers a compact and technologically simple hardware platform with excellent application potential for vertical-channel organic transistors in complex logic circuits.

The development of vertical organic transistors with controllable threshold voltage is highly desirable for integrated circuit-based displays and sensors. Here, the authors report vertical organic permeable dual-based transistors with independently tunable on-currents and threshold voltages.

Genetic Code Expansion Facilitates Position-Selective Labeling of RNA for Biophysical Studies

Nature relies on reading and synthesizing the genetic code with high fidelity. Nucleic acid building blocks that are orthogonal to the canonical A-T and G-C base-pairs are therefore uniquely suitable to facilitate position-specific labeling of nucleic acids. Here, we employ the orthogonal kappa-xanthosine-base-pair for in vitro transcription of labeled RNA. We devised an improved synthetic route to obtain the phosphoramidite of the deoxy-version of the kappa nucleoside in solid phase synthesis. From this DNA template, we demonstrate the reliable incorporation of xanthosine during in vitro transcription. Using NMR spectroscopy, we show that xanthosine introduces only minor structural changes in an RNA helix. We furthermore synthesized a clickable 7-deaza-xanthosine, which allows to site-specifically modify transcribed RNA molecules with fluorophores or other labels.

[Management of bullous pemphigoid]

BACKGROUND

Bullous pemphigoid, the most common autoimmune blistering disease of the skin in adults, is caused by autoantibodies against hemidesmosomal adhesion proteins (BP180/type XVII collagen and BP230), leading into subepidermal blistering. Therefore patients, mostly older than 70 years, show tight bullae and erosions of the skin and rarely at mucous membranes.

PROBLEM

Usually the disease shows a chronically relapsing course. Thus there is a need for long-term topical corticosteroids and if necessary systemic immunosuppressives. Still there is no curative treatment available. In the context of a long-term treatment, drug-specific side effects and also a patient's comorbidities have to be taken into account.

CONCLUSION

The choice of treatment should be based on disease activity and the extent of the muco-cutaneous manifestations. Dependent on this, high-potent topical class IV corticosteroids are used because of fewer side effects compared to systemic steroids. In case of an intense disease extent or in refractory courses treatment with systemic corticosteroids is usually combined with potentially corticosteroid-sparing immunomodulants such as dapsone or doxycycline or adjuvant immunosuppressives such as azathioprine, mycophenoles or methotrexate. Medium- to long-term an attendant immunosuppressant should be applied to reduce the use of corticosteroids. The CD20-antibody rituximab and high-dose intravenous immunoglobulins are also supplemental off-label options in refractory cases.

Effect of fibrous separators on the performance of lithium–sulfur batteries

In this paper we systematically investigated effect of separator morphology on the performance of Li–S batteries.

Polymer-inorganic coatings containing nanosized sorbents selective to radionuclides. 2. Latex/tin oxide composites for cobalt fixation

Colloidal tin oxide with an average particle size of 3.5 nm, which was ex-situ synthesized by the sol-gel method, has been attached to the surface of amino-functionalized poly(acrylate-co-silane) latex particles with a diameter of 100 nm to yield a composite with selective sorption properties toward Co(2+) ions. Electrokinetic properties and the colloidal stability of the synthesized latex/SnO2 composites have been evaluated in dependence on SnO2 content and pH; the sorption capacity and distribution coefficients of composites for Co(2+) ions were in accordance with the SnO2 content and its sorption performance as an individual compound. Composite coatings obtained by casting latex/SnO2 dispersions on quartz sand spiked with (57)Co radionuclide have efficiently eliminated radionuclides migration from the surface when the SnO2 volume fraction in the film was 3.5-4.7%. Furthermore, at these SnO2 loadings, the composite coatings retained the coherent structure of the original latex coating with SnO2 particles homogeneously distributed over the film thickness. The presence of competing Ca(2+) ions in the leaching media at a concentration of above 0.01 mol/L results in a decrease of the distribution coefficients of the latex/SnO2 composite and significantly higher (57)Co leaching. The value of the distribution coefficient of the sorption material to be used in latex composite coatings to prevent migration of radionuclides shall be close to 10(6) mL/g.

Molecular structure of hydrazoic acid with hydrogen-bonded tetramers in nearly planar layers

Hydrazoic acid (HN(3))--potentially explosive, highly toxic, and very hygroscopic--is the simplest covalent azide and contains 97.7 wt % nitrogen. Although its molecular structure was established decades ago, its crystal structure has now been solved by X-ray diffraction for the first time. Molecules of HN(3) are connected to each other by hydrogen bonds in nearly planar layers parallel to (001) with stacking sequence A, B, ... The layer distance, at 2.950(1) Å, is shorter than that in 2H-graphite [3.355(2) Å]. The hydrogen bonds N-H···N are of great interest, since the azido group consists of three homonuclear atoms with identical electronegativity, but different formal charges. These hydrogen bonds are bifurcated into moderate ones with ≈2.0 Å and into weak ones with ≈2.6 Å. The moderate ones build up tetramers (HN(3))(4) in a nearly planar net of eight-membered rings. To the best of our knowledge, such a network of tetramers of a simple molecule is unique.

Structures of HIV TAR RNA-ligand complexes reveal higher binding stoichiometries

Target TAR by NMR: Tripeptides containing arginines as terminal residues and non-natural amino acids as central residues are good leads for drug design to target the HIV trans-activation response element (TAR). The structural characterization of the RNA-ligand complex by NMR spectroscopy reveals two specific binding sites that are located at bulge residue U23 and around the pyrimidine-stretch U40-C41-U42 directly adjacent to the bulge.

Detecting Specific Ligand Binding to Nucleic Acids: A Test for Ultrasoft Laser Mass Spectrometry

Results from a new laser based mass spectrometry method termed LILBID (laser induced liquid bead ion desorption) are presented, which demonstrate the potential for the soft mass analysis of nucleic acids and their specific complexes in solution. On-demand micro droplets, injected into vacuum, are irradiated by intense mid IR-laser pulses. A subsequent explosive phase transition leads to the emission of solvated biomolecular ions into vacuum, which are then mass analyzed by time of flight mass spectrometry. The method is very soft and allows the detection of specific noncovalent complexes. Furthermore it is very tolerant against various buffers and detergents and the charge states of the observed ions reflect qualitatively the charge state in solution. With a required volume of analyte solution in the micro litre range at micromolar concentration, the total consumption of analyte is in the picomolar region. Regarding a single droplet only it is even three orders of magnitude lower, underlining the very high sensitivity of this method. Here we present first examples of the LILBID mass analysis of single stranded DNA (up to a 77mer) and of specific DNA duplices, which show nearly no dissociation under ultrasoft desorption conditions. In case of model hairpin DNA, forming duplices, a sequence specific binding of Dervan-type polyamides into the minor groove of the DNA was observed, and in case of a Tat-TAR model complex strong indications for a specific binding of the Tat protein into the bulge of the wt-RNA was found. Mass spectra of the ribosome of thermos thermophilus give evidence of the applicability of LILBID-MS to analyze large RNA/protein complexes even in the MDa region.

Binding sites of the viral RNA element TAR and of TAR mutants for various peptide ligands, probed with LILBID: a new laser mass spectrometry

A new laser-based mass spectrometry method, called laser induced liquid bead ion desorption (LILBID), was applied to investigate RNA:ligand interactions. As model system the HIV Tat:TAR transactivation complex and its binding behavior were analyzed. TARwt of HIV Type 1 and Type 2 and different artificial mutants were compared regarding their binding to Tat and different peptide ligands. Specific and nonspecific association to TAR was deduced, with the bulge being the well known specific binding site of TAR. In the case of triple arginine (RRR) as a nonspecific ligand, multiple electrostatic binding to TAR was found at higher concentration of RRR. This contrasted with the formation of only ternary complexes in competitive binding studies with TAR, Tat, and potential inhibitors. The fact that the stoichiometries of the complexes can be determined is a major advantage of MS methods over the widely applied fluorimetric methods. A quantitative evaluation of the spectra by a numeric model for ternary complex formation allows conclusions about the role and strength of the binding sites of the RNAs, the specificity and affinity of different ligands, the determination of apparent IC50 and KD values, and a comparison of the binding efficiencies of potential inhibitors.

Fluorescence correlation spectroscopy at single molecule level on the Tat–TAR complex and its inhibitors

The TAR element of HIV and the viral protein Tat form a molecular switch regulating transcriptional efficiency in HIV. We show that fluorescence correlation spectroscopy at the single molecule level is a powerful method to study the association between a Tat-derived peptide and TAR fragments. We also investigated the inhibition of the peptide-RNA complex by different ligands. Utilizing cross correlation measurements, the dissociation constants (K(D)) were determined. To demonstrate the important role of the bulge for the binding of Tat, we compared wt-TAR with three RNA mutants, mainly differing in the bulge region. For the TAR mutants studied at equimolar concentration of RNA and peptide (25 nM), the K(D) values are 15-35 times larger than that of wt-TAR. This gives evidence that the bulge region is the most crucial part of the TAR RNA for specific Tat binding. The IC(50) values for different inhibitors of the Tat/TAR complex both with wt-TAR and mutants have been determined. Neamine conjugate proved to be the best inhibitor of the complex formation. Our results are in agreement with earlier published data on this system using alternative biophysical and biochemical methods, respectively.