Search

The magnetic properties of Fe-Si-B-P-C-Cu nanocrystalline powders were investigated. Fe-Si-B-P-C-Cu powders with a mostly amorphous structure were prepared by an atomization method. The atomized powders were annealed in inert gas atmosphere for nanocrystallization. The Fe84.8Si0.5B9.4P3.5C1Cu0.8nanocrystalline powder exhibits high Bs of 1.76T, which is appreciably higher than that of conventional Fe-based amorphous powders (1.3 - 1.5 T) and close to that of Fe3.5Si4.5Cr (1.86T) crystalline one. The magnetic loss of toroidal core made of the Fe84.8Si0.5B9.4P3.5C1Cu0.8 nanocrystalline powder is also the lowest compared to that of amorphous and crystalline counterparts. This result indicates that Fe-Si-B-P-C-Cu nanocrystalline powders could contribute in efficiency-improvement as well as miniaturization of soft-magnetic cores. [ABSTRACT FROM AUTHOR]

Fe-based alloy powders with a high Fe content of about 81 at.% were produced by a gas-atomization technique. Powders of Fe81Si1.9B5.7P11.4 (at.%) alloy showed a good glass forming ability and exhibited unusual high saturation magnetic flux density of 1.57 T. The core-loss property at a frequency of 100 kHz for the compacted core made of the Fe81Si1.9B5.7P11.4 powder is evaluated to be less than 500 kW/m³ under a maximum induction of 100 mT. Moreover, good DC-superposition characteristic of the core was also confirmed. These results suggest that the present Fe-based alloy powder is promising for low-loss magnetic-core materials and expected to contribute in miniaturization of electric parts in the near future. [ABSTRACT FROM AUTHOR]

Ultrabroadband terahertz generation up to 200 THz has been demonstrated using a 5 fs Ti:sapphire laser and a 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate (DAST) crystal. The high-frequency components beyond 100 THz are much stronger than those generated using conventional electro-optic crystals such as GaSe. A simple simulation of the difference frequency generation in the DAST crystal by considering the refractive index dispersion can reproduce the broadband generation of the terahertz wave and its chirp dependence. Because the generated terahertz wave is coherent and has a broad bandwidth, it can serve as a suitable light source for ultrabroadband terahertz time-domain spectroscopy of a material. [ABSTRACT FROM AUTHOR]

Fe-Si-B-P-Cu nanocrystalline alloy were treated with ball-mill using a lubricant as a process control agent (PCA). The resulting alloy powder is a strong candidate material for soft magnetic composites. Two ball milling methods (continuous and interval) were employed to control the interactions between the PCA and the alloy surface, and their effect on the microstructure of the prepared alloy particles was investigated. The alloy sheet was broken into small pieces and deformed plastically into flake-shaped particles regardless of the ball milling method implemented. Friction-force microscopy of the alloy immersed in the PCA revealed that the friction coefficient of the alloy surface exposed to air for a certain period was higher than that of the unexposed alloy surface (immediately after polishing). During ball milling, the ratio of the newly generated surface to the oxidized surfaces of the alloy subjected to interval milling was smaller than that of the alloy subjected to continuous milling. Therefore, the friction coefficient of the surface of the alloy subjected to interval milling was higher than that of the alloy subjected to continuous milling. Synchrotron radiation analysis revealed that the alloy subjected to interval milling exhibited enhanced surface friction, showing an obvious steepness and inflection in the diffraction intensity as a function of the tilt angle based on the Schulz reflection method. This indicates formation of crystallographic texture in α-Fe grains in an amorphous matrix. Hence, we demonstrated successfully that the ball milling process induced a crystallographic texture in the Fe-based nanocrystalline alloy due to plastic deformation due to the enhanced surface friction. The surface of the alloy was prepared based on the effect of the interfacial interactions between the alloy surface and the PCA., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)

Adenyl cobamide (commonly known as pseudovitamin B 12 ) is synthesized by intestinal bacteria or ingested from edible cyanobacteria. The effect of pseudovitamin B 12 on the activities of cobalamin-dependent enzymes in mammalian cells has not been studied well. This study was conducted to investigate the effects of pseudovitamin B 12 on the activities of the mammalian vitamin B 12 -dependent enzymes methionine synthase and methylmalonyl-CoA mutase in cultured mammalian COS-7 cells to determine whether pseudovitamin B 12 functions as an inhibitor or a cofactor of these enzymes. Although the hydoroxo form of pseudovitamin B 12 functions as a coenzyme for methionine synthase in cultured cells, pseudovitamin B 12 does not activate the translation of methionine synthase, unlike the hydroxo form of vitamin B 12 does. In the second enzymatic reaction, the adenosyl form of pseudovitamin B 12 did not function as a coenzyme or an inhibitor of methylmalonyl-CoA mutase. Experiments on the cellular uptake were conducted with human transcobalamin II and suggested that treatment with a substantial amount of pseudovitamin B 12 might inhibit transcobalamin II-mediated absorption of a physiological trace concentration of vitamin B 12 present in the medium.

The surface protective antigen (Spa) protein of Erysipelothrix rhusiopathiae is an important component in protecting pigs against swine erysipelas. The Spa protein has been antigenically divided into 3 types: SpaA, SpaB, and SpaC. Swine erysipelas vaccines are formulated with strains of serovar 1 and/or 2, both of which are SpaA-possessing serovars. The association of Spa type with E. rhusiopathiae serovar has been reported, and therefore, the determination of the Spa type and the serovar of clinical isolates are important to assess vaccine efficacy. An E. rhusiopathiae strain, designated Ireland, was isolated from a diseased pig and identified as serovar 6 by a conventional agar gel precipitation test. Sequence analysis of the chromosomal locus presumably defining the serovar antigenicity of E. rhusiopathiae revealed that the gene content and organization of the chromosomal regions of the Ireland strain were identical to those of the serovar 6 reference strain (Tuzok). Sequence analysis of the spa gene and dot blots using a SpaA-specific monoclonal antibody confirmed that, unlike the Tuzok strain possessing SpaB, the Ireland strain expressed SpaA, indicating that the Spa type is not associated with the serovar in this strain. Thus, further investigation into the association between Spa type and serovar of clinical swine isolates is warranted.

The [2+2] cycloaddition-retroelectrocyclization (CA-RE) between N,N-dialkylaniline-substituted alkynes and 7,7,8,8-tetracyanoquinodimethane (TCNQ) is employed to fabricate functional cross-linked polymer films containing the intramolecular charge-transfer (CT) chromophores at the cross-linking points. Polystyrene bearing N,N-dialkylaniline-substituted alkynes (P1) and TCNQ polyester (P2) are mixed in tetrahydrofuran (THF), then this solution is spray-coated onto an indium tin oxide or glass plate. Heating to 100 °C initiates the [2+2] CA-RE reaction, resulting in the formation of cross-linked polymer films. The reaction progress and completion are evaluated by monitoring the CT absorption band and cyano vibration peaks. The resulting cross-linked polymer films show reversible cathodic electrochromism between the neutral and anion radical states. In addition, they also display the visual detection behavior of protic acids and Lewis acids, such as Ag + ions. Accordingly, the Ag + ion-loaded polymer films are prepared, and their antibacterial activities are studied. As more Ag + ions are loaded, the CT band more bathochromically shifts and more potent antibacterial activities are obtained. Therefore, the antibacterial activity of the polymer films can be visually recognized by the film colors. Furthermore, the loaded Ag + ions can be released from the polymer films by application of an electrochemical potential., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A 2-year-old male cynomolgus monkey (Macaca fascicularis) showed neurological symptoms during quarantine for importation into Japan, and was euthanized due to poor prognosis. Gross anatomical examination revealed a hemorrhagic lesion around the lateral ventricle in the cerebrum. Histologically, severe diffused suppurative meningitis and ventriculitis were detected with numerous Gram-negative bacilli in the cerebrum. Immunohistochemically, the bacilli were positively stained with an antibody against Klebsiella pneumoniae. The bacterium was isolated from the liver, and it was confirmed to be K. pneumoniae by 16S rDNA sequencing. The isolate displayed a hypermucoviscosity phenotype, was positive for the rmpA and k 2 A genes, and demonstrated multidrug resistance. These results suggest that invasive K. pneumoniae can cause septicemic infection, characterized by severe diffused suppurative meningoencephalitis in monkeys.

Vitamin B 12 was determined and characterized in 19 dried Chlorella health supplements. Vitamin contents of dried Chlorella cells varied from <0.1 μg to approximately 415 μg per 100 g of dry weight. Subsequent liquid chromatography/electrospray ionization-tandem mass spectrometry analyses showed the presence of inactive corrinoid compounds, a cobalt-free corrinoid, and 5-methoxybenzimidazolyl cyanocobamide (factor IIIm) in four and three high vitamin B 12 -containing Chlorella tablets, respectively. In four Chlorella tablet types with high and moderate vitamin B 12 contents, the coenzyme forms of vitamin B 12 5'-deoxyadenosylcobalamin (approximately 32%) and methylcobalamin (approximately 8%) were considerably present, whereas the unnaturally occurring corrinoid cyanocobalamin was present at the lowest concentrations. The species Chlorella sorokiniana (formerly Chlorella pyrenoidosa) is commonly used in dietary supplements and did not show an absolute requirement of vitamin B 12 for growth despite vitamin B 12 uptake from the medium being observed. In further experiments, vitamin B 12 -dependent methylmalonyl-CoA mutase and methionine synthase activities were detected in cell homogenates. In particular, methionine synthase activity was significantly increased following the addition of vitamin B 12 to the medium. These results suggest that vitamin B 12 contents of Chlorella tablets reflect the presence of vitamin B 12 -generating organic ingredients in the medium or the concomitant growth of vitamin B 12 -synthesizing bacteria under open culture conditions.

The hydrolysis of tert-butyldimethylsilyl L-menthyl ether (3) in a CH2Cl2-1 M HCl biphasic solvent system was accelerated by the addition of sodium tetracyanocyclopentadienides 1. Particularly, the reaction rate was enhanced using sodium salt 1a-c with a lipophilic substituent on the cyclopentadienide ring. From the results obtained by a triphasic experiment, hydrolysis proceeds via the formation of hydronium ion 2 in the aqueous phase by ion exchange, followed by the transfer of 2 to the CH2Cl2 phase.

Fluoroquinolones reportedly induce hypoglycemia through stimulation of insulin secretion from pancreatic β-cells via inhibition of K(ATP) channels and activation of L-type voltage-dependent Ca(2+) channels. In physiological condition, the cytosolic Ca(2+) concentration ([Ca(2+)](c)) is also regulated by release of Ca(2+) from intracellular Ca(2+) stores. In this study, we investigated the mechanism of insulin secretion induced by fluoroquinolones, with respect to intracellular Ca(2+) stores. Even where the absence of supplemental extracellular Ca(2+), insulin secretion and [Ca(2+)](c) were increased by gatifloxacin, levofloxacin or tolbutamide. Insulin secretion and the rise of [Ca(2+)](c) induced by fluoroquinolones were reduced by depleting of Ca(2+) in endoplasmic reticumum (ER) by thapsigargin, and inhibiting ryanodine receptor of ER by dantrolene. Inhibition of inositol 1,4,5-triphosphate receptor of ER by xestospongin C suppressed insulin secretion induced by fluoroquinolones, whereas it did not affect [Ca(2+)](c). Destruction of acidic Ca(2+) stores such as lysosome and lysosome-related organelles by glycyl-L-phenylalanine-2-nephthylamide (GPN) did not affect insulin secretion and the rise of [Ca(2+)](c) induced by fluoroquinolones. The increase in insulin and [Ca(2+)](c) induced by tolbutamide were reduced by thapsigargin, dantrolene, and GPN but not by xestospongin C. In conclusion, fluoroquinolones induces Ca(2+) release from ER mediated by the ryanodine receptor, and the reaction might involve in insulin secretion. Sulfonylureas induce Ca(2+) release from GPN-sensitive acidic Ca(2+) stores, but fluoroquinolones did not.

The aim of this work was to determine whether it is possible to distinguish between fertile (control group, already fathers) and infertile men (suspected infertility), by comparing the fluorescence intensity of the sperm-DNA after incubation with appropriate dyes. First we examined two different DNA-specific dyes (DAPI and YOYO-1) using bull spermatozoa. Based on good results in immunohistochemical applications, YOYO-1 was chosen for further work. The fluorescence-intensity of 200 single, morphologically normal spermatozoa in each semen sample were measured in a cytophotometer, means + SD determined and histograms delineated. Of 20 samples from the control group, 17 had markedly higher fluorescence-intensity than did 7/15 of the suspected infertile men. It is concluded that the DNA of the latter seven samples was less accessible to the dye than was the DNA of the control group. There are cases of infertility known in which there is loss of one or more of the DNA-binding proteins, which in spermatozoa are mainly (85%) protamines. The relationship between the stainability of the sperm-DNA and the packaging with DNA-binding proteins is discussed. Two of the histograms showed abnormalities in the distribution of the fluorescence-intensities, one sample was extremely fragile and most of the sperm lysed during the staining-procedure. Five samples showed normal histograms in comparison with the control group.