Adsorption studies on nano-zirconia in water and a water-1,2-propanediol mixture

C. Renger,P. Kuschel,A. Kristoffersson,B. Clauss,W. Oppermann,W. Sigmund 한양대학교 세라믹연구소 2006 Journal of Ceramic Processing Research Vol.7 No.2

The adsorption of an electrosteric (polyacrylic acid, PAA), an electrostatic (triammonium citrate, TAC) and a steric dispersant (2-(2-(2 methoxy ethoxy) ethoxy)acetic acid, TODA) onto nanozirconia particles in deionized (d.i.) water and in a 75 wt% water-25 wt% 1,2-propanediol mixture was investigated. The amount of dispersant in d.i. water yielding the lowest apparent viscosity was measured via rheology. For PAA this was determined to be 6 wt%, for TAC 2 wt% (which corresponds to ≈ 0.43 mg/m2) and for TODA also 2 wt% (corresponding to ≈ 0.34 mg/m2). In the water-propanediol mixture the minimum viscosity was measured and the adsorbed amount was determined by adsorption isotherms using the depletion method. For TAC this was ≈ 0.076 mg/m2, which is five times less than the value in pure water. Furthermore, zeta-potential measurements were performed to confirm the dispersion mechanism. Zirconia particles in water showed the same zeta-potential as in waterpropanediol, although in water-propanediol less TAC molecules were adsorbed on the surface. For TODA the adsorbed amount was calculated to be ≈ 0.4 mg/m2, which fits well to the value determined in water. Propanediol seems not to influence the adsorption in that case.

Determining attitudinal and behavioral factors concerning milk and dairy intake and their association with calcium intake in college students

Angela M. Rose,Rachel A. Williams,Brooke Rengers,Julie A. Kennel,Carolyn Gunther 한국영양학회 2018 Nutrition Research and Practice Vol.12 No.2

BACKGROUND/OBJECTIVES: Average intake of calcium among college students is below the recommended intake, and knowledge surrounding the attitudinal and behavioral factors that influence milk and dairy intake, a primary food source of calcium, is limited. The purpose of this study was to evaluate college students’ attitudes and behaviors concerning milk and dairy consumption and their association with calcium intake. SUBJECTS/METHODS: Participants were 1,730 undergraduate students who completed an online survey (SurveyMonkey) as part of baseline data collection for a social marketing dairy campaign. The online survey assessed attitudes and behaviors concerning milk and dairy intake, and calcium intake. Questions about milk- and dairy-related attitudes and behaviors were grouped into 14 factors using factor analysis. Predictors of calcium intake were then evaluated. RESULTS: Median calcium intake across all participants was 928.6 ㎎/day, with males consuming higher calcium intakes than females (P < 0.001). Adjusted for gender, calcium intakes were most strongly (and positively) correlated with associating milk with specific eating occasions and availability (i.e., storing calcium-rich foods in one’s dorm or apartment) (both P < 0.001). Other correlates of calcium intake included: positive-viewing milk as healthy (P = 0.039), having family members who drink milk) (P = 0.039), and taking calcium supplements (P = 0.056); and negative-parent rules concerning milk (P = 0.031) and viewing milk in dining halls negatively (P = 0.05). CONCLUSIONS: Calcium intakes among college students enrolled in the current study was below the recommended dietary allowance of 1,000 ㎎/day, reinforcing the need for dietary interventions in this target population, especially females. Practitioners and researchers should consider the factors found here to impact calcium intake, particularly associating milk with specific eating occasions (e.g., milk with breakfast) and having calcium-rich foods available in the dorm room or apartment, as intervention strategies in future efforts aimed at promoting milk and dairy foods and beverages for improved calcium intake in college students.

Minimal alterations in T-type calcium channel gating markedly modify physiological firing dynamics

Tscherter, A.,David, F.,Ivanova, T.,Deleuze, C.,Renger, J. J.,Uebele, V. N.,Shin, H. S.,Bal, T.,Leresche, N.,Lambert, R. C. Blackwell Publishing Ltd 2011 The Journal of physiology Vol.589 No.7

Selective T-Type calcium channel block in thalamic neurons reveals channel redundancy and physiological impact of ITwindow.

Dreyfus, Fanny M,Tscherter, Anne,Errington, Adam C,Renger, John J,Shin, Hee-Sup,Uebele, Victor N,Crunelli, Vincenzo,Lambert, Ré,gis C,Leresche, Nathalie The Society 2010 The Journal of neuroscience Vol.30 No.1

<P>Although it is well established that low-voltage-activated T-type Ca(2+) channels play a key role in many neurophysiological functions and pathological states, the lack of selective and potent antagonists has so far hampered a detailed analysis of the full impact these channels might have on single-cell and neuronal network excitability as well as on Ca(2+) homeostasis. Recently, a novel series of piperidine-based molecules has been shown to selectively block recombinant T-type but not high-voltage-activated (HVA) Ca(2+) channels and to affect a number of physiological and pathological T-type channel-dependent behaviors. Here we directly show that one of these compounds, 3,5-dichloro-N-[1-(2,2-dimethyl-tetrahydro-pyran-4-ylmethyl)-4-fluoro-piperidin-4-ylmethyl]-benzamide (TTA-P2), exerts a specific, potent (IC(50) = 22 nm), and reversible inhibition of T-type Ca(2+) currents of thalamocortical and reticular thalamic neurons, without any action on HVA Ca(2+) currents, Na(+) currents, action potentials, and glutamatergic and GABAergic synaptic currents. Thus, under current-clamp conditions, the low-threshold Ca(2+) potential (LTCP)-dependent high-frequency burst firing of thalamic neurons is abolished by TTA-P2, whereas tonic firing remains unaltered. Using TTA-P2, we provide the first direct demonstration of the presence of a window component of Ca(2+) channels in neurons and its contribution to the resting membrane potential of thalamic neurons and to the Up state of their intrinsically generated slow (<1 Hz) oscillation. Moreover, we demonstrate that activation of only a small fraction of the T-type channel population is required to generate robust LTCPs, suggesting that LTCP-driven bursts of action potentials can be evoked at depolarized potentials where the vast majority of T-type channels are inactivated.</P>

Effect of Rheedia longifolia Leaf Extract and Fractions on the P2X_7 Receptor In Vitro: Novel Antagonists?

José A.A. Santos,Antonio Augusto Fidalgo-Neto,Robson X. Faria,Ana Simo˜es,Andrea S. Calheiros,Ana Luiza Be´renger,Hugo C.C. Faria-Neto,Maria Raquel Figueiredo,Valber S. Luiz Frutuoso,Luiz Anastacio Al 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.9

Recently, the P2X_7 receptor has been reported to be associated with chronic inflammatory and neuropathic pain. Because Rheedia longifolia extract has analgesic and anti-inflammatory activity, we evaluated the in vitro inhibitory potential of methanol extract and fractions from its leaves on the P2X_7 purinergic receptor. The activity of P2X_7 was studied with a dye uptake assay and with the whole-cell patch clamp technique in mouse peritoneal macrophages treated with methanol extract of R. longifolia leaves and fractions. The dye uptake was evaluated by flow cytometry and fluorescence microscopy. The R. longifolia extract and some fractions showed an inhibitory effect on the P2X_7 purinergic receptor in a dose-dependent manner. The ethyl acetate fraction exhibited the most potent inhibitory effects. The methanol extract and the butanol fraction showed the same inhibitory effects, despite their lower potency compared with the other fractions. The R. longifolia extract and some of its fractions may be anti-inflammatory because of their inhibitory effect on the P2X_7 receptor. Further investigation is needed to determine the pattern of inhibition and selectivity. Chromatographic analysis indicated the presence of bisflavonoids in the methanol extract fractions. A member of this chemical family is the most probable active compound responsible for the P2X_7 inhibitory effects present in the R. Longifolia extract and fractions.

Chemical Profile and Antinociceptive Efficacy of Rheedia longifolia Leaf Extract

José A.A. Santos,Andrea Calheiros,Diogo D. Nascimento,Ana Luiza R. Bérenger,Fábio C. Amendoeira,Hugo C. Castro-Faria-Neto,Maria Raquel Figueiredo,Luiz A. Alves,Valber da Silva Frutuoso 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.9

Different species of the family Clusiaceae, including Rheedia longifolia, are used in folk medicine to treat inflammatory diseases. This family is largely distributed in tropical and subtropical areas of Brazil, but their chemical and pharmacological properties have been the subject of a few studies. In previous studies, we found that the aqueous extract from R. longifolia leaves presented important anti-inflammatory and analgesic activity. We investigated the chemical profile of R. longifolia and characterized the pharmacological effect of different chemically identified fractions in pharmacological models of neurogenic and inflammatory nociception. The pharmacological tests showed that oral treatment with aqueous crude extract and fractions of methanol extract of R. longifolia leaf induced a significant antinociceptive effect using von Frey filaments. In addition, the most polar fractions presented antinociceptive activity in a neurogenic model of nociception (capsaicin model). The chromatographic analysis indicated the presence of bisflavonoids in the fractions obtained from the methanol extract. These results suggest that bisflavonoids found in methanol-extracted fractions are involved in the inhibition of inflammatory and neurogenic nociception. It is important that the R. longifolia aqueous extract treatment inhibited ulcer formation induced by indomethacin, suggesting an anti-ulcerogenic activity closely associated with its analgesic effect.