Antiferromagnetic Fe^III₆ Ring and Single-Molecule Magnet Mn^II₃Mn^III₄ Wheel

Reactions of a quadridentate ligand [N-(2-hydroxy-5-nitrobenzyl)iminodiethanol] with iron and manganese chloride in methanol yielded an antiferromagnetic FeIII6 ring and a single-molecule magnet MnII3MnIII4 wheel, respectively

Antiferromagnetic Fe^III₆ Ring and Single-Molecule Magnet Mn^II₃Mn^III₄ Wheel

Reactions of a quadridentate ligand [N-(2-hydroxy-5-nitrobenzyl)iminodiethanol] with iron and manganese chloride in methanol yielded an antiferromagnetic FeIII6 ring and a single-molecule magnet MnII3MnIII4 wheel, respectively

Thermosensitive Diblock Copolymer of Poly(<i>N-</i>isopropylacrylamide) and Poly(ethylene glycol) in Water: Polymer Preparation and Solution Behavior

This investigation focused on the self-assembly of poly(N-isopropylacrylamide)-block-poly(ethylene glycol) (PNIPA-block-PEG) in water. A quasi-living radical polymerization technique including a Ce(IV) ion redox system enabled us to prepare block copolymers with relatively narrow molecular weight distributions. We distinguish five regions in the phase diagram:  a transparent sol, opaque sol, transparent gel, opaque gel, and syneresis. By examining the extent of changes in the spectroscopic properties of a fluorescence probe, pyrene, as a function of block polymer concentration and/or temperature, we determined the critical association concentration as well as the partition coefficient Kv for pyrene. The spectroscopic properties indicate that the hydrophobicity around the probe starts to increase far below the demixing line of the PNIPA-block-PEG, a remarkable finding which suggests that even in the temperature region below the LCST temperature of a PNIPA block (∼32 °C), this block copolymer provides more space for a preferential transfer of pyrene molecules than a bulk water medium at a higher temperature. This result may be attributed to the action of water, which starts to behave as a selective solvent for PEG blocks; the PEG chains are more swollen with water than are the PNIPA chains. Dynamic light scattering measurements also indicate that contraction of the PNIPA block starts to occur around 18 °C, which is consistent with results obtained by fluorescence measurements. By employing small-angle neutron scattering, it is also confirmed that microphase separation occurs above 17 °C to form disordered micelles, which includes a range of states from (i) asymmetric swelling to (ii) micelle formation with only short-range liquidlike order. Above 30 °C, network domains are formed as a result of macrophase separation due to dehydration of PNIPA blocks. As the temperature increased up to 40 °C, the network domain is collapsed along a direction parallel to PNIPA-block-PEG interface, leading to increase in interfacial thickness and to macroscopic syneresis

Effect of defects on <i>Q</i> factors of single-crystal diamond MEMS resonators

A resonator with a high Q factor is generally pursued in the single-crystal diamond (SCD) microelectromechanical system (MEMS) for high-performance sensors. In this report, we investigate the oxygen etching effect of SCD on the Q factors of the SCD resonators by using the Raman spectroscopy spatial mapping. We aim to establish the etch pit effect on the Q factors of the SCD MEMS resonators. The 2D Raman imaging technique discloses the dislocations and the local stress in the SCD MEMS resonators in microscale. It is observed that the full width half maximum (FWHM) of the Raman spectra of the SCD resonators has marked relationship with the Q factors of the SCD resonators. The etch pits resulted from the dislocations have weak influence on the Q factors of the SCD resonators.</p

Combined SANS, SEC, NMR, and UV−Vis Studies of Simultaneous Living Anionic Copolymerization Process: Simultaneous Elucidation of Propagating Living Chains at Three Different Length Scales

We studied a simultaneous living anionic copolymerization of styrene (S) and isoprene (I) monomers in a dilute solution with deuterated benzene as a solvent by means of combined time-resolved measurements of small-angle neutron scattering (SANS), size exclusion chromatography (SEC), nuclear magnetic resonance (NMR), and ultraviolet−visible spectroscopy (UV−vis). We observed structural change of the living chains during the polymerization process in three different length scales on the same solution and in a single batch, which enabled us to explore simultaneously the time changes in the local structure (living chain ends), the primary structure (propagating chains), and the higher order structure (the star-like local aggregates of the living chains). We found the copolymerization process is divided into two time regions, defined by regions I and II. In region I, the copolymerization of S and I monomers occurred and all I monomers were consumed at the end of region I, while in region II, pure polystyrene (PS) block chains are formed. In the beginning of region II (region IIa), living polymers having isoprenyl anion (PI−) started to change rapidly into those having styryl anion (PS−), and followed by a slow change from PI− to PS− in the latter part of region II (region IIb). As a consequence of the polymerization of S monomers under the coexistence of PI− and PS−, we found the following two phenomena: (i) an increase in Mw/Mn; (ii) the effective conversion rate of S monomers being slow compared with the corresponding homopolymerization of S monomers. The theoretical analysis of the time-resolved SANS profiles elucidated the time change in the association number of the living chain ends n: n ∼ 4 in region I, n decreases from 4 to 2 in region IIa, and n ∼ 2 in region IIb

sj-docx-2-ine-10.1177_15910199221135308 - Supplemental material for Distal radial artery approach is safe and effective for cerebral angiography and neuroendovascular treatment: A single-center experience with ultrasonographic measurement

Supplemental material, sj-docx-2-ine-10.1177_15910199221135308 for Distal radial artery approach is safe and effective for cerebral angiography and neuroendovascular treatment: A single-center experience with ultrasonographic measurement by Motoyuki Umekawa, Satoshi Koizumi, Kenta Ohara, Daiichiro Ishigami, Satoru Miyawaki and Nobuhito Saito in Interventional Neuroradiology</p

The relationship between activity, correlation time and power law exponent.

<p>(a) Correlation time <i>t_rz</i> versus the activity <i>A</i>(<i>t</i>) (b) Exponent <i>μ</i> versus the activity <i>A</i>(<i>t</i>). For clarity, the activity is plotted in a log scale.</p

sj-pptx-1-ine-10.1177_15910199221135308 - Supplemental material for Distal radial artery approach is safe and effective for cerebral angiography and neuroendovascular treatment: A single-center experience with ultrasonographic measurement

Supplemental material, sj-pptx-1-ine-10.1177_15910199221135308 for Distal radial artery approach is safe and effective for cerebral angiography and neuroendovascular treatment: A single-center experience with ultrasonographic measurement by Motoyuki Umekawa, Satoshi Koizumi, Kenta Ohara, Daiichiro Ishigami, Satoru Miyawaki and Nobuhito Saito in Interventional Neuroradiology</p

Control of Self-Assembling Processes of Polyamidoamine Dendrimers and Pd Nanoparticles

We have investigated the self-assembly formed by palladium acetate (Pd(OAc)2) and polyamidoamine dendrimers (GN-NH2) in a mixed solvent of methanol and N,N-dimethylformamide. We aim to explore effects of the generation number (GN) and concentration of the dendrimers, [GN-NH2], on the self-assembly of the dendrimers (defined hereafter as “templates”) and the Pd nanoparticles inside the templates in order to clarify physical factors controlling the self-assembling mechanisms. For this purpose, we changed GN from 0 to 4 and [GN-NH2] from 0.03 to 2.7 mM, keeping the concentration of Pd(OAc)2, [Pd(OAc)2], at a fixed value of 3.6 mM. The self-assemblies of the templates and the Pd nanoparticles were investigated by means of a combined method of small-angle neutron and X-ray scattering, ultra-small-angle X-ray scattering, dynamic light scattering, and transmission electron microscopy. We elucidated the following two facts concerning the effects of increasing GN on the self-assembly under a fixed value of [−NH2] such that [Pd(OAc)2]/[−NH2] = 3.33, where [−NH2] is molar concentration of the peripheral amine group of dendrimers having varying GN. (i) The size of the templates becomes smaller, while the number density of the templates increases. This trend is well explained from the viewpoint that the effective binding force between the templates via attractive interactions of Pd(OAc)2 and amine groups of the dendrimers, which belong to different templates, becomes weak relatively to the random thermal force acting on the templates. (ii) The size of Pd nanoparticles becomes larger with increasing GN. This result can be rationalized by the following two effects:  (a) increasing number fraction of Pd(OAc)2 molecules, which are easily reduced to Pd(0) atoms; (b) increasing number density of Pd(OAc)2 per single template as detailed in the text (section 4.2.1. and 4.2.3.). As for the effect of [GN-NH2], we found that the templates are formed only when [GN-NH2] falls below a critical value and thereby a sufficient amount of Pd(OAc)2 exists as the binders between the dendrimers. Otherwise dendrimers are molecularly dispersed in solution

Evolutionary Design of Choline-Inducible and -Repressible T7-Based Induction Systems

By assembly and evolutionary engineering of T7-phage-based transcriptional switches made from endogenous components of the <i>bet</i> operon on the <i>Escherichia coli</i> chromosome, genetic switches inducible by choline, a safe and inexpensive compound, were constructed. The functional plasticity of the BetI repressor was revealed by rapid and high-frequency identification of functional variants with various properties, including those with high stringency, high maximum expression level, and reversed phenotypes, from a pool of BetI mutants. The plasmid expression of BetI mutants resulted in the choline-inducible (Bet-ON) or choline-repressible (Bet-OFF) switching of genes under the <i>p</i>T7/<i>betO</i> sequence at unprecedentedly high levels, while keeping the minimal leaky expression in uninduced conditions