Isolable Diaminophosphide Boranes

Metalation of secondary diaminophosphine boranes by alkali metal amides provides a robust and selective access route to a range of metal diaminophosphide boranes M[(R₂N)₂P(BH₃)] (M=Li, Na, K; R=alkyl, aryl) with acyclic or heterocyclic molecular backbones, whereas reduction of a chlorodiaminophosphine borane gave less satisfactory results. The metalated species were characterized in situ by NMR spectroscopy and in two cases isolated as crystalline solids. Single-crystal XRD studies revealed the presence of salt-like structures with strongly interacting ions. Synthetic applications of K[(R₂N)₂P(BH₃)] were studied in reactions with a 1,2-dichlorodisilane and CS₂, which afforded either mono- or difunctional phosphine boranes with a rare combination of electronegative amino and electropositive functional disilanyl groups on phosphorus, or a phosphinodithioformate. Spectroscopic studies gave a first hint that removal of the borane fragment may be feasible.     

Surface modified TiO2/reduced graphite oxide nanocomposite anodes for lithium ion batteries

Journal of Solid State Electrochemistry - Anatase TiO2 nanoparticles with an average crystallite size of ~ 20 nm are synthesized through a sol-gel method. A composite anode for...     

Flexibility of planar graphs of girth at least six

Let container class="MathJax CtxtMenu_Attached_0" jax="CHTML" tabindex="0" ctxtmenu_counter="0" style="font-size: 121.1%; position: relative;">cation="graphic/jgt22567-math-0001.png" data-semantic-complexity="1" class="MJX-TEX" aria-hidden="true">class="mjx-i" data-semantic-type="identifier" data-semantic-role="latinletter" data-semantic-font="italic" data-semantic-annotation="clearspeak:simple" data-semantic-id="0" data-semantic-complexity="1">c class="mjx-c1D43A TEX-I">c>ctable="on" display="inline">c/jgt22567-math-0001.png" data-semantic-complexity="1">c-type="identifier" data-semantic-role="latinletter" data-semantic-font="italic" data-semantic-annotation="clearspeak:simple" data-semantic-="" data-semantic-complexity="1">Gcontainer> be a planar graph with a list assignment container class="MathJax CtxtMenu_Attached_0" jax="CHTML" tabindex="0" ctxtmenu_counter="1" style="font-size: 121.1%; position: relative;">cation="graphic/jgt22567-math-0002.png" data-semantic-complexity="1" class="MJX-TEX" aria-hidden="true">class="mjx-i" data-semantic-type="identifier" data-semantic-role="latinletter" data-semantic-font="italic" data-semantic-annotation="clearspeak:simple" data-semantic-id="0" data-semantic-complexity="1">c class="mjx-c1D43F TEX-I">c>ctable="on" display="inline">c/jgt22567-math-0002.png" data-semantic-complexity="1">c-type="identifier" data-semantic-role="latinletter" data-semantic-font="italic" data-semantic-annotation="clearspeak:simple" data-semantic-="" data-semantic-complexity="1">Lcontainer>. Suppose a preferred color is given for some of the vertices. We prove that if container class="MathJax CtxtMenu_Attached_0" jax="CHTML" tabindex="0" ctxtmenu_counter="2" style="font-size: 121.1%; position: relative;">cation="graphic/jgt22567-math-0003.png" data-semantic-complexity="1" class="MJX-TEX" aria-hidden="true">class="mjx-i" data-semantic-type="identifier" data-semantic-role="latinletter" data-semantic-font="italic" data-semantic-annotation="clearspeak:simple" data-semantic-id="0" data-semantic-complexity="1">c class="mjx-c1D43A TEX-I">c>ctable="on" display="inline">c/jgt22567-math-0003.png" data-semantic-complexity="1">c-type="identifier" data-semantic-role="latinletter" data-semantic-font="italic" data-semantic-annotation="clearspeak:simple" data-semantic-="" data-semantic-complexity="1">Gcontainer> has girth at least six and all lists have size at least three, then there exists an container class="MathJax CtxtMenu_Attached_0" jax="CHTML" tabindex="0" ctxtmenu_counter="3" style="font-size: 121.1%; position: relative;">cation="graphic/jgt22567-math-0004.png" data-semantic-complexity="1" class="MJX-TEX" aria-hidden="true">class="mjx-i" data-semantic-type="identifier" data-semantic-role="latinletter" data-semantic-font="italic" data-semantic-annotation="clearspeak:simple" data-semantic-id="0" data-semantic-complexity="1">c class="mjx-c1D43F TEX-I">c>ctable="on" display="inline">c/jgt22567-math-0004.png" data-semantic-complexity="1">c-type="identifier" data-semantic-role="latinletter" data-semantic-font="italic" data-semantic-annotation="clearspeak:simple" data-semantic-="" data-semantic-complexity="1">Lcontainer>-coloring respecting at least a constant fraction of the preferences.     

High-rate LDPC codes from partially balanced incomplete block designs

Journal of Algebraic Combinatorics - This paper presents a combinatorial construction of low-density parity-check (LDPC) codes from partially balanced incomplete block designs. Since...     

Photoactivatable Fluorophore for Stimulated Emission Depletion (STED) Microscopy and Bioconjugation Technique for Hydrophobic Labels

The use of photoactivatable dyes in STED microscopy has so far been limited by two-photon activation through the STED beam and by the fact that photoactivatable dyes are poorly solvable in water. Herein, we report ONB-2SiR, a fluorophore that can be both photoactivated in the UV and specifically de-excited by STED at 775 nm. Likewise, we introduce a conjugation and purification protocol to effectively label primary and secondary antibodies with moderately water-soluble dyes. Greatly reducing dye aggregation, our technique provides a defined and tunable degree of labeling, and improves the imaging performance of dye conjugates in general.     

Studying nanomagnets and magnetic heterostructures with X-ray PEEM at the Swiss Light Source

Polarization dependent X-ray absorption spectroscopy and microscopy enables the element selective investigation of magnetic systems at the nanoscale. At the Swiss Light Source a photoemission electron microscope is used for the study of a broad variety of systems. Here, a review of recent activities is presented with a focus on instrumental and analytical developments. A new procedure for the 3 dimensional determination of the magnetization vector has been developed, and is demonstrated for GdFeCo microstructures displaying in-plane and out-of-plane domains, and sub-20 nm Fe nanoparticles. The recent progress for measurements in applied magnetic fields is presented and a new set-up for time-resolved measurements employing femtosecond laser pulses is described.     

The effects of thermal treatments on the thermoluminescence properties of biogenic minerals present in the seashells

In this study, thermoluminescence (TL) properties of the biogenic minerals present in the seashell samples at different temperatures and annealing times have been studied. Three explicit peaks are seen in the glow curves roughly at 100°C, 180°C, and 380°C. One of the prominent results is that annealing above 600°C affects enormously the TL intensity, whereas no remarkable TL intensity is observed for unannealed samples. The highest intensity and area under the curve were observed at 700°C annealing temperature, and 180 minutes annealing time and 1500 times bigger than the unannealed samples. A linear dose response is observed between 2.4 and 72?Gy and beyond this value, a sublinear relation is observed. Unfortunately, a huge decrease in TL intensity is observed about 51% of its initial value, after 5 hours of storage time.     

On an improved adaptive reduced-order model for the computation of steady-state vibrations in large-scale non-conservative systems with friction joints

Nonlinear Dynamics - Joints are commonly used in many large-scale engineering systems to ease assembly, and ensure structural integrity and effective load transmission. Most joints are designed...     

Spectroscopic and Electronic Properties of Molybdacarborane Complexes with Non-innocently Acting Ligands

The molybdacarboranes [3-{L-κ²N,N}-3-(CO)₂-closo-3,1,2-MoC₂B₉H₁₁] (L=2,2′-bipyridine (2,2′-bpy, 1 a ) or 1,10-phenanthroline (1,10-phen, 1 b )) incorporating well-known potentially non-innocent ligands (CO, 2,2′-bpy, 1,10-phen) and the “non-spectator” nido-carborane ([η⁵-C₂B₉H₁₁]²⁻) ligand were prepared and fully characterised. High-resolution mass spectrometry, single-crystal X-ray diffraction methods, spectroscopy (IR, (resonance) Raman, NMR), cyclic voltammetry and spectroelectrochemistry (electrochemical properties) were supported by theoretical investigations of the electronic structure (DFT, CAS-SCF, TD-DFT).     

On existence of log minimal models and weak Zariski decompositions

We first introduce a weak type of Zariski decomposition in higher dimensions: an -Cartier divisor has a weak Zariski decomposition if birationally and in a numerical sense it can be written as the sum of a nef and an effective -Cartier divisor. We then prove that there is a very basic relation between Zariski decompositions and log minimal models which has long been expected: we prove that assuming the log minimal model program in dimension d − 1, a lc pair (X/Z, B) of dimension d has a log minimal model (in our sense) if and only if K _X  + B has a weak Zariski decomposition/Z.