37 research outputs found
Strong ferromagnetism in Pt-coated ZnCoO: The role of interstitial hydrogen
We observed strong ferromagnetism in ZnCoO as a result of high concentration hydrogen absorption. Coating ZnCoO with Pt layer, and ensuing hydrogen treatment with a high isostatic pressure resulted in a highly increased carrier concentration of 10(21)/cm(3). This hydrogen treatment induced a strong ferromagnetism at low temperature that turned to superparamagnetism at about 140 K. We performed density functional method computations and found that the interstitial H dopants promote the ferromagnetic ordering between scattered Co dopants. On the other hand, interstitial hydrogen can decrease the magnetic exchange energy of Co-H-Co complexes, leading to a reduction in the blocking temperature.open7
Cordycepin Increases Nonrapid Eye Movement Sleep via Adenosine Receptors in Rats
Cordycepin (3′-deoxyadenosine) is a naturally occurring adenosine analogue and one of the bioactive constituents isolated from Cordyceps militaris/Cordyceps sinensis, species of the fungal genus Cordyceps. It has traditionally been a prized Chinese folk medicine for the human well-being. Because of similarity of chemical structure of adenosine, cordycepin has been focused on the diverse effects of the central nervous systems (CNSs), like sleep regulation. Therefore, this study was undertaken to know whether cordycepin increases the natural sleep in rats, and its effect is mediated by adenosine receptors (ARs). Sleep was recorded using electroencephalogram (EEG) for 4 hours after oral administration of cordycepin in rats. Sleep architecture and EEG power spectra were analyzed. Cordycepin reduced sleep-wake cycles and increased nonrapid eye movement (NREM) sleep. Interestingly, cordycepin increased θ (theta) waves power density during NREM sleep. In addition, the protein levels of AR subtypes (A1, A2A, and A2B) were increased after the administration of cordycepin, especially in the rat hypothalamus which plays an important role in sleep regulation. Therefore, we suggest that cordycepin increases theta waves power density during NREM sleep via nonspecific AR in rats. In addition, this experiment can provide basic evidence that cordycepin may be helpful for sleep-disturbed subjects
Cuban Sugar Cane Wax Acid and Policosanol Showed Similar Atheroprotective Effects with Inhibition of LDL Oxidation and Cholesteryl Ester Transfer via Enhancement of High-Density Lipoproteins Functionality
Background. Cuban sugarcane wax acids (SCWA) and policosanol (PCO) are mixtures of higher aliphatic acids and alcohols, respectively, purified from sugarcane wax with different chief components. Although it has been known that they have antioxidant and anti-inflammatory activities, physiological properties on molecular mechanism of SCWA have been less studied than PCO. Methods. In this study, we compared antiatherogenic activities of SCWA and PCO via encapsulation with reconstituted high-density lipoproteins (rHDL). Results. After reconstitution, SCWA-rHDL showed smaller particle size than PCO-rHDL with increase of content. PCO-rHDL or SCWA-rHDL showed distinct inhibition of glycation with similar extent in the presence of fructose. PCO-rHDL or SCWA-rHDL showed strong antioxidant activity against cupric ion-mediated oxidation of low-density lipoproteins (LDL), and inhibition of oxLDL uptake into macrophages. Although PCO-rHDL showed 1.2-fold stronger inhibition against cholesteryl ester transfer protein (CETP) activity than SCWA-rHDL, SCWA-rHDL enhanced 15% more brain cell (BV-2) growth and 23% more regeneration of tail fin in zebrafish. Conclusion. PCO and SCWA both enhance the beneficial functions of HDL to maximize its antioxidant, antiglycation, and antiatherosclerotic activities and the inhibition of CETP. These enhancements of HDL functionality by PCO and SCWA could exert antiaging and rejuvenation activity
Cuban Sugar Cane Wax Acid and Policosanol Showed Similar Atheroprotective Effects with Inhibition of LDL Oxidation and Cholesteryl Ester Transfer via Enhancement of High-Density Lipoproteins Functionality
The Ability of Different Ketohexoses to Alter Apo-A-I Structure and Function In Vitro and to Induce Hepatosteatosis, Oxidative Stress, and Impaired Plasma Lipid Profile in Hyperlipidemic Zebrafish
In the current study, we have tested the nonenzymatic glycation activities of ketohexoses, such as tagatose and psicose. Although tagatose-treated apoA-I (t-A-I) and psicose-treated apoA-I (p-A-I) exerted more inhibitory activity you cupric ion-mediated low-density lipoprotein (LDL) oxidation and oxidized LDL (oxLDL) phagocytosis into macrophage than fructose-treated apoA-I (f-A-I). In the lipid-free state, t-A-I and f-A-I showed more multimerized band without crosslinking. Since t-A-I lost its phospholipid binding ability, the rHDL formation was not as successful as f-A-I. However, injecting t-A-I showed more antioxidant activities in zebrafish embryo under the presence of oxLDL. Three weeks of consumption of fructose (50% of wt in Tetrabit/4% cholesterol) showed a 14% elevation of serum triacylglycerol (TG), while tagatose-administered group showed 30% reduction in serum TG compared to high cholesterol control. Fructose-fed group showed the biggest area of Oil Red O staining with the intensity as strong as the HCD control. However, tagatose-consumed group showed much lesser Oil Red O-stained area with the reduction of lipid accumulation. In conclusion, although tagatose treatment caused modification of apoA-I, the functional loss was not as much severe as the fructose treatment in macrophage cell model, zebrafish embryo, and hypercholesterolemic zebrafish model
The Ability of Different Ketohexoses to Alter Apo-A-I Structure and Function In Vitro and to Induce Hepatosteatosis, Oxidative Stress, and Impaired Plasma Lipid Profile in Hyperlipidemic Zebrafish
Improved Eco-Friendly Photovoltaics Based on Stabilized AgBiS2 Nanocrystal Inks
AgBiS2 nanocrystals (NCs) have emerged as attractive absorbers in eco-friendly photovoltaics because of their nontoxic components and high absorption coefficient. Native long-chain ligands of AgBiS2 NCs should be replaced with short-chain ligands for their photovoltaics; however, conventional approaches have been performed using solid-state ligand exchange (SSLE), resulting in inhomogeneous NC aggregation, broad bandtail, large trap density, and resultantly low open-circuit voltage (VOC) in devices. Herein, we first report that long-chain ligands of AgBiS2 NCs are replaced with halometallate-based short ligands via solution-phase ligand exchange (SPLE). AgI and BiI3 are used as halometallate sources, and we find that colloidally stable, highly concentrated AgBiS2 NC inks in polar solvents are prepared via SPLE using AgI-based halometallates, enabling one-step-deposition suitable for roll-to-roll process. This leads to higher degree of ligand exchange, sharper bandtail, lower trap density, and resultantly higher VOC in devices compared to conventional SSLE. We also first demonstrate that the photovoltaic performance can be improved by introducing ethanedithiol-exchanged AgBiS2 NCs on SPLE-prepared AgBiS2 NC solids because of favorable band alignment and extended depletion width. Thus, this enables improving device performance up to a power conversion efficiency of 4.08% with the highest VOC of 0.55 V among the AgBiS2 NC photovoltaics reported so far. ©1
Short-Term Consumption of Cuban Policosanol Lowers Aortic and Peripheral Blood Pressure and Ameliorates Serum Lipid Parameters in Healthy Korean Participants: Randomized, Double-Blinded, and Placebo-Controlled Study
The current study was designed to investigate the short-term effects of policosanol consumption on blood pressure (BP) and the lipid parameters in healthy Korean participants with prehypertension. A total of 84 healthy participants were randomly allocated to three groups receiving placebo, 10 mg of policosanol, or 20 mg of policosanol for 12 weeks. Based on an average of three measurements of peripheral BP, the policosanol 20 mg group exhibited the most significant reduction, that is, up to 7.7% reduction of average systolic BP (SBP) from 136.3 ± 6.1 mmHg (week 0) to 125.9 ± 8.6 mmHg (week 12, p < 0.001). Between group comparisons using repeated measures ANOVA showed that the policosanol 20 mg group had a significant reduction of SBP at 12 weeks (p = 0.020) and a reduction of diastolic BP (DBP) at 8 weeks (p = 0.041) and 12 weeks (p = 0.035). The policosanol 10 mg and 20 mg groups showed significant reductions in aortic SBP of 7.4% and 8.3%, respectively. The policosanol groups showed significant reductions of total cholesterol (TC) of 9.6% and 8.6% and low-density lipoproteins (LDL-C) of 21% and 18% for 10 mg and 20 mg of policosanol, respectively. Between group comparisons using repeated measures ANOVA showed that the policosanol (10 mg and 20 mg) groups at 12 weeks had a significant reduction of TC (p = 0.0004 and p = 0.001) and LDL-C (p = 0.00005 and p = 0.0001) and elevation of %HDL-C (p = 0.048 and p = 0.014). In conclusion, 12-week consumption of policosanol resulted in significant reductions of peripheral SBP and DBP, aortic SBP and DBP, mean arterial pressure (MAP), and serum TC and LDL-C with elevation of % HDL-C
Age-Related Decrease in Stress Responsiveness and Proactive Coping in Male Mice
Coping is a strategic approach to dealing with stressful situations. Those who use proactive coping strategies tend to accept changes and act before changes are expected. In contrast, those who use reactive coping are less flexible and more likely to act in response to changes. However, little research has assessed how coping style changes with age. This study investigated age-related changes in coping strategies and stress responsiveness and the influence of age on the processing of conditioned fear memory in 2-, 12- and 23-month-old male mice. Coping strategy was measured by comparing the escape latency in an active avoidance test and by comparing responses to a shock prod. The results showed that proactivity in coping response gradually decreased with age. Stress responsiveness, measured by stress-induced concentration of corticosterone, was also highest in 2-month-old mice and decreased with age. Consolidation of fear memory was highest in 12-month-old mice and was negatively correlated with the degree of stress responsiveness and proactivity in coping. Fear extinction did not differ among age groups and was not correlated with stress responsiveness or the proactivity of coping. However, the maintenance of extinct fear memory, which was best in 2-month-old mice and worst in 12-month-old mice, was negatively correlated with stress responsiveness but not with coping style. Age-dependent changes in the expression of glucocorticoid receptor (GR) and its regulatory co-chaperones, which are accepted mechanisms for stress hormone stimulation, were measured in the hippocampus. The expression of GR was increased at 12 months compared to other age groups. There were no differences in Hsp70 and BAG1 expression by age. These results can be summarized as follows: (1) stress responsiveness and proactivity in coping decreased with age class; (2) consolidation of fear memory was negatively correlated with both stress responsiveness and proactivity; however, maintenance of extinct fear memory was negatively correlated with stress responsiveness only; and (3) consolidation and maintenance of extinct fear memory appeared to be more influenced by factors other than stress reactivity and proactivity in coping, such as the amount of hippocampal glucocorticoid expression