Earth abundant manganese bismuth (MnBi) has long been of interest due to its largemagnetocrystalline anisotropy and high energy density for advanced permanent magnet applications. However, solution ...synthesis of MnBi phase is challenging due to the reduction potential mismatch between Mn and Bi elements. In this study, we show a versatile MnBi synthesis method involving the metal co-reduction followed by thermal annealing. The magnetically hard MnBi crystalline phase is then exchange coupled with magnetically soft cobalt coating. Our processing approach offers a promising strategy for manufacturing rare-earth-free magnetic nanocrystals.
The objective of this study was to examine the role of oxygen radicals, protein kinase C (PKC), and ATP-sensitive K(+) (K(ATP)) channels in mediating flumazenil-produced preconditioning. Chick ...cardiomyocyte death was quantified using propidium iodide, and oxygen radical generation was assessed using 2',7'-dichlorofluorescin oxidation. Preconditioning was initiated with 10 min of ischemia followed by 10 min of reoxygenation. Alternatively, flumazenil was infused for 10 min and removed 10 min before ischemia. Flumazenil (10 microM) and preconditioning increased oxygen radicals 1,693 +/- 101 (n = 3) and 1,567 +/- 98 (n = 3), respectively, vs. 345 +/- 53 (n = 3) in control and reduced cell death similarly 22 +/- 3% (n = 5) and 18 +/- 2% (n = 6), respectively, vs. controls 49 +/- 5% (n = 8). Protection and increased oxygen radicals by flumazenil were abolished by pretreatment with the antioxidant thiol reductant 2-mercaptopropionyl glycine (800 microM; 52 +/- 10%, n = 6). Specific PKC inhibitors Go-6976 (0.1 microM) and chelerythrine (2 microM), given during ischemia and reoxygenation, blocked flumazenil-produced protection (47 +/- 5%, n = 6). The PKC activator phorbol 12-myristate 13-acetate (0.2 microM), given during ischemia and reoxygenation, reduced cell death similarly to that with flumazenil 17 +/- 4% (n = 6) and 22 +/- 3% (n = 5). Finally, 5-hydroxydecanoate (1 mM), a selective mitochondrial K(ATP) channel antagonist given during ischemia and reoxygenation, abolished the protection of flumazenil and phorbol 12-myristate 13-acetate. Thus flumazenil mimics preconditioning to reduce cell death in cardiomyocytes. Oxygen radicals activate mitochondrial K(ATP) channels via PKC during the process.
Development of electric vehicles (EVs) has great significance for protecting the environment, saving energy and improving energy structure. The Ni/MH power battery is one of the most practical ...batteries as a power source for EVs. The properties of Ni/MH power batteries are described and the status of application of Ni/MH power batteries for EVs in Japan, USA and China is reviewed. A 150Ah 6V battery pack made by Beijing General Research Institute for Non-ferrous Metal (GRINM) has passed the test of National Key Laboratory and exhibits superior charge–discharge characteristics. A 100 Ah 120 V battery pack firstly has been fitted on an EVs in China and gained successful running demonstration.
A design for radar absorbing materials (RAM) is given, including theory, methodology and techniques. To illustrate RAM design theory and methods, the tracking calculation method and pure-shape ...optimum are also briefly introduced. In addition, the design process and examples of a multi-layer absorber are provided. The features of the multi-layer absorber design are a kind of broad-band and thin-type absorber.
In light of the antinociceptive activity of the short-chain neurotoxin, cobrotoxin, and other acetylcholine antagonists, the antinociceptive activity and mechanisms of cobratoxin (CTX), a long-chain ...postsynaptic alpha-neurotoxin, was investigated in rodent pain models.
CTX was administered intraperitoneally (30, 45, 68 microg/kg), intra-cerebral ventricularly (4.5 microg/kg) or microinjected into periaqueductal gray (PAG; 4.5 microg/kg). The antinociceptive action was tested using the hot-plate and acetic acid writhing tests in mice and rats. The involvement of the cholinergic system and opioid system in CTX-induced analgesia was examined by pretreatment of animals with atropine (0.5 mg/kg, im; or 10 mg/kg, ip) or naloxone (1 and 5 mg/kg, ip). The effect of CTX on motor activity was tested using the Animex test.
CTX exhibited a dose-dependent analgesic action in mice as determined by both the hot-plate and acetic acid writhing tests. The peak effect of analgesia was seen 3 h after administration. In the mouse acetic acid writhing test, the intra-cerebral ventricular administration of CTX at 4.5 microg/kg (1/12th of a systemic dose) produced marked analgesic effects. Microinjection of CTX (4.5 microg/kg) into the PAG region did not elicit an analgesic action in rats in the hot-plate test. Atropine at 0.5 mg/kg (im) and naloxone at 1 and 5 mg/kg (ip) both failed to block the analgesic effects of CTX, but atropine at 10 mg/kg (ip) did antagonize the analgesia mediated by CTX in the mouse acetic acid writhing test. Acetylsalicylic acid (300 mg/kg) did not enhance the analgesic effects of CTX. At the highest effective dose of 68 microg/kg the neurotoxin did not change the spontaneous mobility of mice.
CTX has analgesic effects, which are mediated in the central nervous system though not through the PAG. The central cholinergic system but not opioid system appears to be involved in the antinociceptive action of CTX.
Bound states and their influence on the dynamics of an one-dimensional tight-binding system subject to environments are studied in this paper. We identify specifically three kinds of bound states. ...The first is a discrete bound state (DBS), of which the energy level exhibits a gap from the continuum. The DBS exhibits the similar features of localization as the edge states in the system and thus can suppress the decay of system. The second is a bound state in the continuum (BIC), which can suppress the system decay too. It is found that the BIC is intimately connected to the edge mode of the system since both of them show almost the same features of localization and energy. The third one displays a large gap from the continuum and behaves extendible (not localized). Moreover the population of the system on this state decays partly but not all of them does. This is different from the two former bound states. The time evolution of a single excitation in the system is studied in order to illustrate the influence of the bound states. We found that both DBS and BIC play an important role in the time evolution, for example, the excitation becomes localized and not decay depending on the overlap between the initial state and the DBS or BIC. Furthermore we observe that the single excitation takes a long-range hopping when the system falls into the regime of strong localizations. This feature can be understood as the interplay of system localizations and the bath-induced long-range correlation.
It is postulated that antioxidant properties of American ginseng root mediate its cardioprotective actions. The antioxidant capabilities of the American ginseng root have been demonstrated ...previously, however, the berry of the American ginseng has not yet been evaluated. In this study, we tested the American ginseng berry extract (AGBE) for its antioxidant effects in cell-free chemical systems using H
2O
2/FeSO
4 to generate hydroxyl radicals which were measured by a fluorescent probe, 2′, 7′-dichlorofluorescin diacetate (DCFH/DA). Xanthine/xanthine oxidase was used to generate superoxide anion, which was measured by a fluorescent probe dihydroethidium (DHE). We found that AGBE decreased fluorescence significantly, suggesting that AGBE scavenges oxygen free radicals. We further tested whether AGBE (0.1–1 mg/ml) can protect cardiomyocytes from oxidative injury induced by exogenous or endogenous oxidants. Cells were exposed to either H
2O
2 or antimycin A (a mitochondrial electron transport chain site III inhibitor that augments mitochondrial oxidant production). The resulting oxidant stress was measured using DCFH/DA and the cell death was assessed using propidium iodide staining. Pretreatment with AGBE (1 mg/ml) significantly attenuated DCF fluorescence by 49% or 85% and reduced cell death by 59% or 63% in cells exposed to H
2O
2 or antimycin A, respectively. When the effects of extracts from berry and root of American ginseng were compared in cardiomyocytes exposed to antimycin A, we observed that AGBE conferred greater antioxidant protection at the same dose. We conclude that AGBE is a potent antioxidant that protects cardiomyocytes against oxidant-mediated injury and this protection is partly mediated by its free radical scavenging properties.
Nanocrystalline materials have been characterized by ultra-fine crystallites separated by grain boundaries. The dislocations in the crystallites of nanocrystalline materials form some special ...configurations and the dislocation density drastically decreases. A model is proposed to account for the effects of the defects in the grain boundaries of nanocrystalline materials on the dislocation stability and configuration in the crystallites. Based on the fact that the grain boundaries of nanocrystalline materials contain a large number of vacancies and vacancy clusters, a 1/x3 law for the stress field induced by the vacancies and the vacancy clusters is considered. The region of the dislocation stability in the crystallites is estimated and the dislocation configurations in the crystallites are discussed. The theoretical results are shown to interpret the experimental observations well.
Mono‐Schiff bases containing a crown ether ring (HL1, HL2, HL3 and HL4) and their transition metal complexes were synthesized and characterized by 1H NMR, IR, and mass spectroscopy as well as ...elemental analysis. The oxygenation constants (K O 2) of Schiff base‐Co(II) complexes were measured over the range of −5 to +25 °C, and the values of ΔH° and ΔS° were calculated based on these K O 2 values. Using Mn(III)‐Schiff base complexes, the biomimetic catalytic oxidation of styrene to benzaldehyde was carried out with 100% selectivity. Comparison of this complex with analogues not containing a crown ether moiety clearly demonstrated the influence of crown ether ring on the dioxygen affinities and biomimetic catalytic oxidation performance of the Schiff base complexes.
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