Synthesis of mono- and symmetrical di-N-hydroxy- and N-aminoguanidines

Novel mono- and symmetrical di-N-hydroxy- and N-aminoguanidines were readily prepared from the reaction of diverse hydroxylamines or hydrazines with reagent classes di(benzotriazol-1-yl)methanimine 6, (bis-benzotriazol-1-yl-methylene)amines 8a,b, benzotriazole-1-carboxamidines 10a-i, benzotriazole-1-carboximidamides 11a,b, and N'-hydroxy-1H-1,2,3-benzotriazole-1-carboximidamide 18. The preparation is described for a variety of N-hydroxy- and N-aminoguanidines with different substitution patterns in good yields.     

Fourier–Mukai transform on abelian surfaces

We study moduli spaces of stable sheaves on abelian surfaces whose Mukai vectors are related by a cohomological Fourier-Mukai transform. We show that there is a Fourier-Mukai transform inducing a birational map between them.     

Solutions with moving singularities for a semilinear parabolic equation

We consider the Cauchy problem for a semilinear heat equation with power nonlinearity. It is known that the equation has a singular steady state in some parameter range. Our concern is a solution with a moving singularity that is obtained by perturbing the singular steady state. By formal expansion, it turns out that the remainder term must satisfy a certain parabolic equation with inverse-square potential. From the well-posedness of this equation, we see that there appears a critical exponent. Paying attention to this exponent, for a prescribed motion of the singular point and suitable initial data, we establish the time-local existence, uniqueness and comparison principle for such singular solutions. We also consider solutions with multiple singularities.     

Theoretical studies on the proton and electron transfer (PET) in a pseudo one-dimensional hydrogen bonded network system

We investigated singly ordered phases of the charge density were (CDW), spin density wave (SDW), and singlet superconductivity (SSC) for a pseudo one-dimensional proton and electron transfer (PET) system of quinhydrone crystal by means of the two band model. We performed band structure calculations of model systems, which are (i) the quinone and the p-hydroquinone model and (ii) two semiquinones model. We found that the model (i) exhibits an insulator and the model (ii) exhibits the SDW insulator.     

Thermoreversible gelation on cooling and on heating of an aqueous gelatin–poly(N-isopropylacrylamide) conjugate

A polymer conjugate composed of 43 wt% gelatin and 57 wt% poly(N-isopropylacrylamide) (PNIPAAm) was prepared. The dynamic viscoelastic properties of an aqueous solution of the conjugate at the concentration of 5 wt% were examined. The solution was viscous fluid at 30°C and turned into an elastic homogeneous hydrogel upon heating above 34°C or upon cooling below 10°C. The resultant hydrogels turned back into a solution at the opposite temperature cycles of the gelation. It is considered that the driving force of the gelation is the intermolecular hydrophobic interaction of PNIPAAm blocks or the intermolecular helix association of gelatin blocks, respectively, on heating or on cooling. © 1998 John Wiley & Sons, Ltd.     

Differences in muscle thickness and echo intensity between stroke survivors and age- and sex-matched healthy older adults

Objective: The stroke survivors exhibit change in muscle quantity and quality compared to healthy older adults. This study aimed to compare the muscle thickness (MT) and echo intensity (EI) values of individual muscles between stroke survivors and age- and sex-matched healthy older adults. Methods : In total, 27 stroke survivors and 34 healthy older adults participated in this study. The MT and EI values of the following muscles were assessed from transverse ultrasound images: rectus abdominis (RA), external oblique, internal oblique, transversus abdominis, rectus femoris, vastus intermedius (VI), vastus lateralis (VL), vastus medialis (VM), tibialis anterior (TA), gastrocnemius (Gas), and soleus (Sol). The MT and EI values of these muscles were compared between stroke survivors and healthy older adults. Results : The MT values of the VL, VM, and RA on the non-paretic sides were significantly higher and those of the TA, Gas, and Sol on the paretic sides were significantly lower in the stroke survivors than in the healthy older adults (P < 0.05). The EI values of the VI, VL, VM, TA on the paretic sides and those of the Gas on both the paretic and non-paretic sides were significantly higher in the stroke survivors than in the healthy older adults (P < 0.05). Conclusion : Stroke survivors seem to develop muscle hypertrophy of the non-paretic thigh muscles owing to a compensatory strategy. In addition, the lower-leg muscles on the paretic side of stroke survivors tend to show both quantitative and qualitative muscle changes.     

ChemInform Abstract: First‐Principles Investigation of R2O3(ZnO)3 (R: Al,Ga, and In) in Homologous Series of Compounds.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Cover Picture: Electrochemical Lossy Mode Resonance-based Fiber Optic Sensing for Electroactive Species (Electroanalysis 3/2023)

We present an electrochemical-lossy mode resonance (LMR) sensing method that detects refractive indices and electroactive species. The LMR peaks of indium-tin-oxide in the transmittance-wavelength spectra were significantly shifted as the applied potential between 1.0 and −0.5 V at 209 nm/V. The modulation was exploited for sensing the refractive index and electroactive species (ferrocyanide and methylene blue) in two ways: peak-wavelength tracking and potential scanning. The potential-scanning technique produced clear potential LMR peaks in the transmittance-potential spectra for the first time, which were corresponded to the external refractive index. Meanwhile, the limits of detection of ferrocyanide and methylene blue were 7.5 and 25.3 μM, respectively, in peak-wavelength tracking and 18.2 and 20.8 μM, respectively, in the potential scanning technique.