Molecular Spintronics Based on Single‐Molecule Magnets Composed of Multiple‐Decker Phthalocyaninato Terbium(III) Complex

Unlike electronics, which is based on the freedom of the charge of an electron whose memory is volatile, spintronics is based on the freedom of the charge, spin, and orbital of an electron whose memory is non‐volatile. Although in most GMR, TMR, and CMR systems, bulk or classical magnets that are composed of transition metals are used, this Focus Review considers the growing use of single‐molecule magnets (SMMs) that are composed of multinuclear metal complexes and nanosized magnets, which exhibit slow magnetic‐relaxation processes and quantum tunneling. Molecular spintronics, which combines spintronics and molecular electronics, is an emerging field of research. Using molecules is advantageous because their electronic and magnetic properties can be manipulated under specific conditions. Herein, recent developments in [LnPc]‐based multiple‐decker SMMs on surfaces for molecular spintronic devices are presented. First, we discuss the strategies for preparing single‐molecular‐memory devices by using SMMs. Next, we focus on the switching of the Kondo signal of [LnPc]‐based multiple‐decker SMMs that are adsorbed onto surfaces, their characterization by using STM and STS, and the relationship between the molecular structure, the electronic structure, and the Kondo resonance of [TbPc₂]. Finally, the field‐effect‐transistor (FET) properties of surface‐adsorbed [LnPc₂] and [Ln₂Pc₃] cast films are reported, which is the first step towards controlling SMMs through their spins for applications in single‐molecular memory and spintronics devices.     

Selective thioether macrocyclization of peptides having the N-terminal 2-chloroacetyl group and competing two or three cysteine residues in translation

The mode of thioether macrocyclization of peptides containing an N-terminal 2-chloroacetyl group and two or three competing cysteine residues at downstream positions has been extensively studied, leading to a strategy for designated formation of overlapping-bicyclic peptides or dumbbell-type bicyclic peptides.     

MNBA-mediated β-lactone formation: mechanistic studies and application for the asymmetric total synthesis of tetrahydrolipstatin

Various β-lactones were prepared from β-hydroxycarboxylic acids by intramolecular dehydration condensation using MNBA, an effective coupling reagent, along with a nucleophilic catalyst. The transition state that provides the desired 4-membered ring model system is disclosed by density functional theory (DFT) calculations, and the structural features of the transition form are discussed. This method was successfully applied to the asymmetric total synthesis of tetrahydrolipstatin (THL), an antiobestic drug used in clinical treatment to inhibit the activity of pancreatic lipase.     

Application of Probe Electrospray Ionization Mass Spectrometry (PESI-MS) to Clinical Diagnosis: Solvent Effect on Lipid Analysis

We have examined several combinations of solvents with the aim of optimizing the ionization conditions for molecular diagnosis of malignant tumours by PESI-MS. Although the best conditions may depend on the actual species in the sample, the optimal conditions for renal cell carcinoma (RCC) were achieved by using alcohols. PESI-MS successfully delineated the differential expression of phospholipids (PCs) and triacylglycerols (TAGs) in noncancerous and RCC tissues by using these solvent systems. This study paves the way for the application of PESI-MS in medical samples.     

Generation and stabilization of ultrafast optical pulse trains with monolithic mode-locked laser diodes

In this paper, we report on the generation and the stabilization of ultrafast optical pulse trains exceeding 100 GHz from monolithic mode-locked laser diodes (MLLDs) combined with some new techniques such as subharmonic synchronous mode-locking (SSML) and repetition-frequency multiplication (RFM) method. Key subjects to increase the pulse repetition frequencies of the MLLDs such as fast absorption recovery and harmonic mode-locking operation are discussed. 500 GHz optical pulse generation from a short-cavity, graded-index separated confinement heterostructure MLLD and THz-rate pulse generation by harmonic mode-locking are reported. We also demonstrate the stabilization of a 160 GHz MLLD by the SSML with subharmonic-frequency optical pulse injection and reveal that the SSML is very promising as a stabilization technique of the ultrafast MLLD beyond the limitations by the electronic device speed. A method to accurately measure the timing jitter of such ultrafast optical pulse train, all-optical down converting using a nonlinear optical device, is also presented. We also mention another choice for ultrafast optical pulse generation using the MLLD combined with a dispersive medium such as an optical fiber. We demonstrate here the generations of stable 84–256 GHz optical pulse trains by the RFM method of the MLLD stabilized by the SSML.     

Background-Free Optical Sampling System Using Si Avalanche Photodiode as Two-Photon Absorber

The introduction of a double-chopping scheme eliminates the background level in the optical sampling system, where a Si avalanche photodiode acts as a two-photon absorber. We successfully demonstrate background-free optical sampling of 40-GHz and 160-GHz pulse trains.     

Pd(O)-catalyzed electroreductive cleavage of allylic acetates

Pd(O)-catalyzed electroreductive cleavage of allylic acetates yielding alkenes and/or allyltrimethylsilanes is described. Deprotection of allyl esters can be performed in the same electrolysis system.     

Triangulations intersect nicely

We show that there is a matching between the edges of any two triangulations of a planar point set such that an edge of one triangulation is matched either to the identical edge in the other triangulation or to an edge that crosses it. This theorem also holds for the triangles of the triangulations and in general independence systems. As an application, we give some lower bounds for the minimum-weight triangulation which can be computed in polynomial time by matching and network-flow techniques. We exhibit an easy-to-recognize class of point sets for which the minimum-weight triangulation coincides with the greedy triangulation.     

Neutron activation analysis of iron and copper at 1013–104 atoms·m−2 on silicon wafer surface

The surface concentrations of copper and iron in currently used silicon wafers are lower than 10¹⁴ atoms·m^–2. To determine such ultra-trace elements accurately by neutron activation analysis, we measured the efficiencies of a well-type Ge detector for⁵⁹Fe -rays and⁶⁴Cu annihilation -rays. We also developed methods for preparing samples for copper and iron analysis including a low-temperature silicon direct-bonding technique. We have applied these techniques to determine copper and iron on the surface of clean silicon wafers, and obtained concentrations of 10¹³–10¹⁴ atoms·m^–2.     

On minimum and maximum spanning trees of linearly moving points

In this paper we investigate the upper bounds on the numbers of transitions of minimum and maximum spanning trees (MinST and MaxST for short) for linearly moving points. Here, a transition means a change on the combinatorial structure of the spanning trees. Suppose that we are given a set ofn points ind-dimensional space,S={p ₁,p ₂, ...p _n }, and that all points move along different straight lines at different but fixed speeds, i.e., the position ofp _i is a linear function of a real parametert. We investigate the numbers of transitions of MinST and MaxST whent increases from-∞ to +∞. We assume that the dimensiond is a fixed constant. Since there areO(n ²) distances amongn points, there are naivelyO(n ⁴) transitions of MinST and MaxST. We improve these trivial upper bounds forL ₁ andL _∞ distance metrics. Letk _p (n) (resp. ) be the number of maximum possible transitions of MinST (resp. MaxST) inL _p metric forn linearly moving points. We give the following results in this paper: κ₁(n)=O(n ^5/2 α(n)),κ _∞(n)=O(n ^5/2 α(n)), , and where α(n) is the inverse Ackermann's function. We also investigate two restricted cases, i.e., thec-oriented case in which there are onlyc distinct velocity vectors for movingn points, and the case in which onlyk points move.