Tran Thu Huong

Luminescent nanomaterials containing rare earth ions for security printing

The high-efficiency luminescent nanomaterials with different emission wavelengths of red (YVO4:Eu3+), green (CePO4:Tb3+), ZnS:Mn2+ and YVO4:Eu3+;@SiO2 were successfully prepared with different concentrations of Mn and rare earth ions as active centres by chemical synthesis. Structure properties were studied. It was found that the particle size of our samples was in the range of 10-30 nm. Photoluminescent properties were studied under 325, 337, 365 and 370 nm excitations in order to apply in luminescent labels. The primary colour components are red and green emission making them very convenient and attractive for screen security printing systems. Hundreds of different labels with a size of 1-10 cm² were prepared by screen-printing as well as inkjet printing. By improving the Epson printer, commercial red, green and blue inks were used in the printing application. Screen and inkjet printing were deemed good methods for security printing. Our products were beautiful, high resolution and withstood tropical weather.

Chrysoeriol isolated from the leaves of Eurya ciliata stimulates proliferation and differentiation of osteoblastic MC3T3-E1 cells

Chrysoeriol (1) was isolated as the main constituent from the methanol extract of the dried leaves of Eurya ciliata Merr. To investigate the bioactivities of 1 on bone metabolism, its effects on the function of osteoblastic MC3T3-E1 cells were studied. Compound 1 significantly increased the growth of MC3T3-E1 cells and caused a significant elevation of alkaline phosphatase activity, collagen content, and nodule mineralization in the cells (P < 0.05). Our data indicate that the enhancement of osteoblast function by 1 may be useful in the prevention of osteoporosis.

Murrayafoline A modulation of rat vascular myocyte Cav1.2 channel: functional, electrophysiological and molecular docking analysis

The carbazole alkaloid murrayafoline A (MuA) enhances contractility and the Ca2+ currents carried by the Cav1.2 channels [ICa1.2] of rat cardiomyocytes. As only few drugs stimulate ICa1.2, this study was designed to analyse the effects of MuA on vascular Cav1.2 channels.

Fabrication and optical characterization of multimorphological nanostructured materials containing Eu(III) in phosphate matrices for biomedical applications

EuPO4·H2O nanorods/nanoparticles with a rhabdophane-type hexagonal form have been successfully synthesized using microwave assisted co-precipitation. The effects of chemical composition and pH on the size, shape, morphology and luminescence properties have been investigated by powder X-ray diffraction, Field Emission Scanning Electron Microscopy (FESEM), and photoluminescence spectroscopy. The mean size of the nanorods is about 15–30 nm in diameter and 200–400 nm in length and the size of nanoparticles is 10–20 nm. A powdered sample of these EuPO4·H2O nanorods/nanoparticles emitted yellow-green light with narrow bands at 594, 619, 652, and 697 nm under UV-vis excitation. The surface effects of the built core–shell structure on the fluorescent properties, and the compatibility of the EuPO4·H2O nanomaterials with a biological system, have been studied to develop a new fluorescent label for biomedical imaging. The primary test results in using a EuPO4·H2O–Immunoglobulin G conjugate for recognizing the measles virus in a vaccine is presented.

Vascular L-Type Ca2+ Channel Blocking Activity of Sulfur-Containing Indole Alkaloids from Glycosmis petelotii

In the search for novel natural compounds endowed with potential antihypertensive activity, a new sulfur-containing indole alkaloid, N-demethylglypetelotine (2), and its known analogue glypetelotine (1), were isolated from the leaves of Glycosmis petelotii. Their structures were established on the basis of spectroscopic evidence. The two alkaloids were assessed for vasorelaxing activity on rat aorta rings and for L-type Ba(2+) current [I(Ba(L))] blocking activity on single myocytes isolated from rat tail artery. Both glypetelotine and N-demethylglypetelotine inhibited phenylephrine-induced contraction with IC50 values of 20 and 50 μM, respectively. The presence of endothelium did not modify their spasmolytic effect. Neither glypetelotine nor N-demethylglypetelotine affected Ca(2+) release from the sarcoplasmic reticulum induced by phenylephrine. The spasmolytic effect of glypetelotine increased with membrane depolarization. In the presence of 60 mM K(+), both compounds inhibited, in a concentration-dependent manner, the contraction induced by cumulative addition of Ca(2+), this inhibition being inversely related to Ca(2+) concentration. Glypetelotine and, less efficiently N-demethylglypetelotine, inhibited I(Ba(L)), the former compound also affecting I(Ba(L)) kinetics. In conclusion, glypetelotine is a novel vasorelaxing agent which antagonizes L-type Ca(2+) channels.

Functional, electrophysiological and molecular docking analysis of the modulation of Cav 1.2 channels in rat vascular myocytes by murrayafoline A.

The carbazole alkaloid murrayafoline A (MuA) enhances contractility and the Ca2+ currents carried by the Cav1.2 channels [ICa1.2] of rat cardiomyocytes. As only few drugs stimulate ICa1.2, this study was designed to analyse the effects of MuA on vascular Cav1.2 channels.

Fabrication and characterization of YVO4:Eu3+ nanomaterials by the micro-wave technique

Abstract Fabrication and characterization of YVO 4 :Eu 3+ nanophosphors prepared by microwave (MW) irradiation assisted soft template synthesis were reported. The effects of synthesis conditions such as different powers of MW irradiation, pH values and concentration of reaction materials on properties of nanophosphor were also investigated to obtain the controllable size, morphology and high luminescence efficiency. Morphology, crystalline structure, and optical properties were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and fluorescence spectroscopy, respectively. The results showed that YVO 4 :Eu 3+ nanophosphors were obtained by using diethyleneglycol (DEG) as soft template, with pH values in the range of 4 to 12, upon microwave irradiation from 300 to 900 W, at temperature of 80 °C. The high fluorescent YVO 4 :Eu 3+ nanocrystals obtained with size from 15 nm down to 8 nm are more effective to develop an ultrahigh sensitive fluorescent label for biomolecule, cell and tissue.

Synthesis and characterization of core/shell structured nanophosphors CePO4:Tb@LaPO4 by solvothermal method

Abstract Core/shell structured CePO4:Tb(III)@LaPO4 and CePO4:Tb(III) were successfully synthesized in tris(2–ethylhexyl) phosphate (TEHP) and diethylene glycol (DEG) solvents for comparison of the two techniques in open air and closed reaction vessel. Morphology and crystal structure of the core/shell nanophosphors were determined by using X-ray diffraction (XRD) and transmission electron microscopy (TEM), which showed that nanophosphors had diameter of about 5–10 nm with the monoclinic monazite phase. The nanophosphors obtained by close vessel procedure showed smaller size, more homogeneity and pure crystallite. The luminescent measurements were done upon the different excitation wavelengths in ultraviolet region and at room temperature to elucidate the influences of the used solvents and the reaction temperatures. It was found that CePO4:Tb@LaPO4 prepared by the close vessel synthesis showed the intensity of green band of the transfer from 5D4 to 7F5 energy level, which was strongly increased, and the luminescent decay time was 3.2 ms, which was longer than that of naked CePO4:Tb phosphor.

Alkylphloroglucinol derivatives and triterpenoids with soluble epoxide hydrolase inhibitory activity from Callistemon citrinus.

Phytochemical analysis of the leaves and stems of Callistemon citrinus (Curtis) Skeels led to the isolation of two new alkylphloroglucinols, gallomyrtucommulone E and F (1 and 2), along with four other known alkylphloroglucinol derivatives, gallomyrtucommulone A (3), endoperoxide G3 (4), myrtucommulone B (5), callistenone B (6) and five known triterpenoids, including betulinic acid (7), 3β-acetylmorolic acid (8), 3β-hydroxy-urs-11-en-13(28)-olide (9), diospyrolide (10) and ursolic acid (11). The structures of the natural compounds were determined from the spectroscopic evidences including 1D-/2D-NMR and HR-MS spectrometry. All the isolated compounds were assessed for the effects on the sEH inhibitory activity. The acylphloroglucinols myrtucommulone B (5)/callistenone B (6) (in mixture), and two triterpenoids, ursolic acid (11) and 3β-hydroxy-urs-11-en-13(28)-olide (9) displayed strong inhibition of sEH activity, with IC50 values of 0.7, 11.2 and 24.8 μM, respectively.

In Vitro Vasoactivity of Zerumbone from Zingiber zerumbet

The sesquiterpene zerumbone, isolated from the rhizome of Zingiber zerumbet Sm., besides its widespread use as a food flavouring and appetiser, is also recommended in traditional medicine for the treatment of several ailments. It has attracted great attention recently for its effective chemopreventive and therapeutic effects observed in various models of cancer. To assess the zerumbone safety profile, a pharmacology study designed to flag any potential adverse effect on vasculature was performed. Zerumbone was tested for vasorelaxing activity on rat aorta rings and for L-type Ba(2+) current blocking activity on single myocytes isolated from the rat-tail artery. The spasmolytic effect of zerumbone was more marked on rings stimulated with 60 mM than with 30 mM K(+) (IC50 values of 16 µM and 102 µM, respectively). In the presence of 60 mM K(+), zerumbone concentration-dependently inhibited the contraction induced by the cumulative additions of Ca(2+), this inhibition being inversely related to the Ca(2+) concentration. Phenylephrine-induced contraction was inhibited by the drug, though less efficiently and independently of the presence of an intact endothelium, without affecting Ca(2+) release from the intracellular stores. Zerumbone inhibited the L-type Ba(2+) current (estimated IC50 value of 458.7 µM) and accelerated the kinetics of current decay. In conclusion, zerumbone showed an overall weak in vitro vasodilating activity, partly attributable to the blocking of the L-type Ca(2+) channel, which does not seem to represent, however, a serious threat to its widespread use.