Learners’ level of understanding of the inclusion relations of quadrilaterals and prototype phenomenon

This paper reports on data from investigations on learners’ understanding of inclusion relations of quadrilaterals, building on the ideas from our earlier study (Fujita & Jones, 2007). By synthesising past and current theories in the teaching of geometry (van Hiele's model, figural concepts, prototype phenomenon, etc.), we propose a theoretical model and method to describe learners’ cognitive development of their understanding of inclusion relations of quadrilaterals, and in order to investigate the topic, data are collected from trainee teachers and lower secondary school students. The findings suggest that in general more than half of above average learners are likely to recognise quadrilaterals primarily by prototypical examples, even though they know the correct definition, and this causes them difficulty in understanding the inclusion relations of quadrilaterals.     

Size control of giant unilamellar vesicles prepared from inverted emulsion droplets

The production of giant lipid vesicles with controlled size and structure will be an important technology in the design of quantitative biological assays in cell-mimetic microcompartments. For establishing size control of giant vesicles, we investigated the vesicle formation process, in which inverted emulsion droplets are transformed into giant unilamellar vesicles (GUVs) when they pass through an oil/water interface. The relationship between the size of the template emulsion and the converted GUVs was studied using inverted emulsion droplets with a narrow size distribution, which were prepared by microfluidics. We successfully found an appropriate centrifugal acceleration condition to obtain GUVs that had a desired size and narrow-enough size distribution with an improved yield so that emulsion droplets can become the template for GUVs.     

High-quality generation of a multispot pattern using a spatial light modulator with adaptive feedback

We propose and demonstrate high-quality generation of a uniform multispot pattern (MSP) by using a spatial light modulator with adaptive feedback. The method iteratively updates a computer generated hologram (CGH) using correction coefficients to improve the intensity distribution of the generated MSP in the optical system. Thanks to a simple method of determining the correction coefficients, the computational cost for optimizing the CGH is low, while maintaining high uniformity of the generated MSP. We demonstrate the generation of a 28×28 square-aligned MSP with high uniformity. Additionally, the proposed method could generate an MSP with a gradually varying intensity profile, as well as a uniform MSP consisting of more than 1000 spots arranged in an arbitrary pattern.     

Development of scattering near-field optical microspectroscopy apparatus using an infrared synchrotron radiation source

We report the status of a scattering near-field microspectroscopy apparatus developed at SPring-8 using an infrared synchrotron radiation (IR-SR) source. It consists of a scattering type scanning near-field optical microscope and a Fourier transform infrared spectrometer. The IR-SR is used as a highly brilliant and broad-band IR source. This apparatus has potential for application in near-field spectroscopy with high spatial resolution beyond the diffraction limit. In order to eliminate background scatterings from the probe shaft and/or sample surface, we used higher harmonic demodulation method. The near-field spectra were observed by 2nd harmonic components using the lock-in detection. The spatial resolution of about 300 nm was achieved at around 1000 cm^? 1 (10 μm wavelength).     

Facile access to (Z)-alkene-containing diketopiperazine mimetics utilizing organocopper-mediated anti-SN2′ reactions

Regio- and stereoselective anti-S_N2′ alkylation of γ-phosphoryloxy-α,β-unsaturated-δ-lactams with organocopper reagents allowing the preparation of N-alkylated-α,δ-substituted-β,γ-unsaturated-δ-lactams as highly functionalized diketopiperazine mimetics is presented.     

Clustering structure of aqueous solution of kinetic inhibitor of gas hydrates

Poly-[N-vinylcaprolactam] (PVCAP) and its related compounds are specific polymeric compounds for inhibiting hydrate formation. To clarify the inhibition mechanism of these compounds on hydrate nucleation at the molecular level, we measured the mass spectra of clusters generated from the fragmentation of liquid droplets including N-methylcaprolactam (NMCAP; functional group of PVCAP). By comparing the mass spectra of clusters of the solutions--pure D2O, tetrahydrofuran (THF)-D2O, NMCAP-D2O, and THF-NMCAP-D2O--it was found that the interaction of NMCAP with D2O was much stronger than that of THF with D2O. The relative intensity ratio of D+(NMCAP)m(D2O)n clusters to all the clusters observed for the NMCAP-D2O (1:250) mixed solution was 0.45. On the other hand, the relative intensity ratio of D+(THF)1(D2O)n clusters to all the clusters observed for the THF-D2O (1:17) mixed solution was 0.15. In the case of the THF-NMCAP-D2O three-component mixed solution, the NMCAP-D2O interaction was more predominant than the THF-D2O interaction, even at a lower NMCAP concentration. NMCAP reduces free mobile water molecules around NMCAP, but THF does not. This correlates with the facts that THF forms its hydrate below the freezing point and that PVCAP works as an inhibitor of gas hydrates.     

Improving chemical recycling rate by reclaiming polyurethane elastomer from polyurethane foam

Flexible polyurethane foam was decomposed into a polyol mixture by an extruder with diethanolamine (DEA) as a decomposing agent. The resulting decomposed product could be used as an alternative virgin polyol in reclaiming polyurethane. In the case of reclaiming elastomer by using the decomposed product without any purification, virgin polyol could be alternated by the decomposed product up to 80%. It is a great improvement compared with the reclamation to foam, whose percentage was maximum 5%. Furthermore, the percentage could be improved up to 100% by purifying the decomposed product. We have found that physical properties of reclaimed polyurethane elastomer, such as tensile strength, hardness, and elongation, can be regulated by the ratio of unrefined/refined polyol. Whereas the tensile strength and the hardness increased as the content increased, the elongation decreased.     

'Nucleo-nanocages': designed ternary oligodeoxyribonucleotides spontaneously form nanosized DNA cages

DNA three-way junctions formed from three 30-mer oligonucleotides that contain single-chained self-complementary sticky ends spontaneously self-assemble into 'nucleo-nanocages': the exo- and endo-nuclease digestion experiments indicate that defects such as the single and double strand end structures are absent on the spherical nano-assemblies, providing clear evidence for the closed nanocage structure.     

Novel synthesis of photocrosslinkable polymers

A new preparative route to photocrosslinkable polymers in which the polymers are produced directly from the polymerization of vinyl monomers having photocrosslinkable groups has been investigated. The photosensitive resins thus produced have higher sensitivity and resolution than conventional photosensitive resins. The monomers were synthesized from the esterification of vinylphenols or vinyl β-chloroethyl ether with cinnamic acid, β-styrylacrylic acid, and their homologs, and from the etherification of vinyl β-chloroethyl ether with hydroxychalcones. Homopolymerizations of these monomers and their copolymerizations with other comonomers were investigated with the use of both radical and ionic initiators. It is shown that radical polymerization of the monomers gave soluble polymers only at low conversion. Anionic initiators did not initiate polymerization. Cationic polymerization imparted soluble polymers in high yield, except for the monomers bearing cyano groups, which generally gave insoluble polymers. Infrared and NMR spectroscopic investigation of the cationically obtained soluble polymers and comparative investigation by cationic polymerization of model compounds indicated that polymerization of the monomers proceeds through the vinyl double bond without affecting the photosensitive unsaturated bond. Thus, linear photocrosslinkable polymers with an intact photoreactive group may be produced by cationic polymerization. In general, these polymers have uniform structure and modifiable physical properties depending on the monomer used. The polymer thus obtained from β-vinyloxyethyl cinnamate has been shown to have excellent properties for use as a photo-resist.     

Formation and fragmentation of the [M + Na]+ ion of glycosides in fast atom bombardment mass spectrometry

Positive-ion fast atom bombardment (FAB) mass spectra of flavonol and steroid glycosides with sodium chloride added showed well known characteristic features; of the appearance of [M + Na]⁺ peaks, disappearance of [M + H]⁺ peaks and a significant decrease in the peak heights of fragment ions. Compared with the features in the FAB mass spectra of crown ethers with addition of salt, and above features suggest a complexation between Na⁺ and the glycosides in matrix solution. The B/E-constant linked scanning technique was used to obtain structural information of the [M + Na]⁺ ion of the glycosides. The B/E spectra gave the daughter-ion peaks, suggesting that coordination of Na⁺ with the biosides and triosides occurs at the sugar moiety, whereas the coordination with the monoglycosides occurs at the aglycone moiety, except for monoglycosides in which the aglycone moiety does not contain significant oxygen functional groups such as OH and CO.