Morphology dependence of 1,2-diphenylethylenediamine-derived organogelator templates in solvents and their influence in the production of nanostructured silica

The 1,2-diphenylethylenediamine-based neutral or cationic organogelator-templates, currently employed in the production of silica nanomaterials, were initially evaluated for their versatile gelation ability and found to be gelled in the majority of organic solvents tested. Scanning electron microscope and transmission electron microscope, images of neutral organogels made from different solvents revealed that they assembled into a plate-shaped, or rod-shaped morphology, respectively in ethanol or butan-1-ol and in acetonitrile or tetrahydrofurane. Similarly, a 1: 1 mixture (mass) of neutral and cationic gelators formed different morphologies in the solvents tested. Sol-gel polycondensation of tetraethoxy silane using either individual gels (neutral or cation) or a 1: 1 mixture of gels was explored. The experimental results and the scanning electron microscopy and transmission electron microscopy images revealed that silica nanotubes with an inner diameter of 82 nm and an outer diameter of 620 nm were obtained from the 1: 1 mixture of neutral and cationic gelator in ethanol, whereas silica nanoparticles were obtained using gels made in the other solvents tested.     

Electronic structure studies of Mg0.95Mn0.05Fe2−2xTi2xO4 (0x0.8)

The electronic structure of Mg_0.95Mn_0.05Fe_2−2xTi_2xO₄ (0x0.8) compound is investigated using near edge X-ray absorption fine structure, (NEXAFS) spectroscopy measurements, carried out at O K, Fe and Ti L_3,2-edges at room temperature. The O K-edge spectra indicate that the Fe 3d orbitals have been considerably modified and a new spectral feature start dominating in the pre-edge region at higher Ti doping. The Fe 2p NEXAFS spectra exhibit a mixed valent Fe²⁺/Fe³⁺ states apart from the conversion of Fe³⁺ to Fe²⁺ with the substitution of Ti ions. The Ti L_3,2-edge spectra indicate that Ti ions remain unchanged at 4+ state. These variations in the host electronic structure due to Ti substitution are consistent with the dielectric and transport properties of the material.     

Can preoperative diffusion-weighted MRI predict postoperative hepatic insufficiency after curative resection of HBV-related hepatocellular carcinoma? A pilot study

Liver fibrosis determines the functional liver reserve. Several studies have reported that the apparent diffusion coefficient (ADC) values of diffusion-weighted magnetic resonance imaging (DW-MRI) can assess liver fibrosis. We investigated whether DW-MRI predicts postoperative hepatic insufficiency and liver fibrosis in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Twenty-six patients with HBV-related HCC who received preoperative DW-MRI on a 3-T MRI system were enrolled between July and December 2008. ADC values were measured twice by two observers. Three “b values” were used: 50, 400 and 800 s/mm². Postoperative hepatic insufficiency was defined as persistent hyperbilirubinemia (total bilirubin level >5 mg/dl for more than 5 days after surgery) or postoperative death without other causes. The mean age (21 men and 5 women) was 51.4 years. Three patients experienced postoperative hepatic insufficiency. liver stiffness measurement predicted postoperative hepatic insufficiency, advanced fibrosis (F3–4), and cirrhosis significantly [area under the receiving operator characteristic curve (AUROC)=0.942, 0.771 and 0.818, respectively, with P=.047, 0.048 and 0.006, respectively]; ADC values of DW-MRI, however, did not (AUROC=0.797, 0.648 and 0.491, respectively, with P=.100, 0.313 and 0.938, respectively). Reliability of ADC values between right and left hepatic lobes (ρ=0.868 and ρ=0.910 in the first and second measures of Observer A; ρ=0.865 and ρ=0.831 in the first and second measures of Observer B) was high and the intra- and interobserver reliability (ρ=0.958 in observer A and ρ=0.977 in observer B; ρ=0.929 in the first measure and ρ=0.978 in the second measure between the two observers) were high. All reliability was significant (P<.001). Our results suggest that DW-MRI on a 3-T MRI system is not suitable for predicting postoperative hepatic insufficiency, advanced liver fibrosis, and cirrhosis in patients with HBV-related HCC, despite significantly high reliability.     

A new photobase generator containing oxime-urethane group and its application

Photochemical base formation from oxime-urethane derivatives was observed via pH changes, GC and HPLC analysis, and laser flash photolysis study. Photolysis of these derivatives results in the formation of amines which induce cross-linking of poly(glycidyl methacrylate) (PGMA) upon heating. Photocross-linking reaction of the copolymers, containing epoxy and oxime-urethane groups, were studied by measuring the insoluble fraction of copolymer films under various reaction conditions. Thermal cross-linking reaction of the copolymer was catalysed by the photogenerated pendant amines. The copolymer containing oxime-urethane groups which photogenerate aromatic amines can be utilized as an image recording material.     

Type-II Red Phosphorus: Wavy Packing of Twisted Pentagonal Tubes

Elemental phosphorus exhibits fascinating structural varieties and versatile properties. The unique nature of phosphorus bonds can lead to the formation of extremely complex structures, and detailed structural information on some phosphorus polymorphs is yet to be investigated. In this study, we investigated an unidentified crystalline phase of phosphorus, type-II red phosphorus (RP), by combining state-of-the-art structural characterization techniques. Electron diffraction tomography, atomic-resolution scanning transmission electron microscopy (STEM), powder X-ray diffraction, and Raman spectroscopy were concurrently used to elucidate the hidden structural motifs and their packing in type-II RP. Electron diffraction tomography, performed using individual crystalline nanowires, was used to identify a triclinic unit cell with volume of 5330 ų, which is the largest unit cell for elemental phosphorus crystals up to now and contains approximately 250 phosphorus atoms. Atomic-resolution STEM imaging, which was performed along different crystal-zone axes, confirmed that the twisted wavy tubular motif is the basic building block of type-II RP. Our study discovered and presented a new variation of building blocks in phosphorus, and it provides insights to clarify the complexities observed in phosphorus as well as other relevant systems.     

Monitoring Transformations of Catalytic Active States in Photocathodes Based on MoSx Layers on CuInS2 Using In Operando Raman Spectroscopy

The electrochemical activation of CuInS₂/MoS_x for photoelectrochemical (PEC) H₂ production was revealed for the first time through in operando Raman spectroscopy. During the activation process, the initial metallic MoS_x phase was transformed to semiconducting MoS_x, which facilitates charge carrier transfer between CuInS₂ and MoS_x. Ex situ X-ray photoelectron spectroscopy and Raman spectroscopy suggest the existence of MoO₃ after the activation process. However, apart from contradicting these results, in operando Raman spectroscopy revealed some of the intermediate steps of the activation process.     

Polyimide Compounds For Post-Lithium Energy Storage Applications

The exploration of cathode and anode materials that enable reversible storage of mono and multivalent cations has driven extensive research on organic compounds. In this regard, polyimide (PI)-based electrodes have emerged as a promising avenue for the development of post-lithium energy storage systems. This review article provides a comprehensive summary of the syntheses, characterizations, and applications of PI compounds as electrode materials capable of hosting a wide range of cations. Furthermore, the review also delves into the advancements in PI based solid state batteries, PI-based separators, current collectors, and their effectiveness as polymeric binders. By highlighting the key findings in these areas, this review aims at contributing to the understanding and advancement of PI-based structures paving the way for the next generation of energy storage systems.     

Image recording material based on the polymeric photobase generator containing oxime‐urethane groups

A polymeric photobase generator containing oxime‐urethane groups was prepared from copolymerization of MMA with N‐[4‐(benzophenoneoximino‐carbonylamino)phenyl]maleimide, a maleimide monomer containing oxime‐urethane group, and its properties as an image recording material were studied. The irradiation of this copolymer with UV light dissociates the urethane linkage to result in the formation of aromatic amino groups, which can be developed by the diazo‐coupling reaction. Various colors could be developed depending on the phenolic coupling reagents as the developer.     

Thermal curing reaction of poly(glycidyl methacrylate) using photogenerated amines from oxime-urethane derivatives

Two oxime-urethane derivatives, benzophenone oxime N-cyclohexylurethane (1 ) and dibenzophenone oxime N,N′-hexamethylenediurethane (2 ), were used as photobase generators. Photolysis of these derivatives results in the formation of amines which induce cross-linking of poly(glycidyl methacrylate) (PGMA) upon heating. The bifunctional derivative 2 is more efficient than the monofunctional derivative 1 in inducing thermal cross-linking of PGMA, with a maximum degree of insolubilization increasing up to ca. 90%.