Strain analysis of misfit dislocations in α-Fe2O 3/α-Al2O 3 heterostructure interface by geometric phase analysis.

The α-Fe2O3/α-Al2O3 heterostructure interfaces have been studied using transmission electron microscopy (TEM). The interface exhibited coherent regions separated by equally spaced misfit dislocations. The misfit dislocations were demonstrated to be edge dislocations with dislocation spacing of ∼4 nm. The strain fields around the misfit dislocation core were mapped using a combination of geometric phase analysis and high-resolution transmission electron microscopy images. The strain measurement results were compared with the Peierls-Nabarro dislocation model and the Foreman dislocation model. These comparisons show that the Foreman model (a=2) is the most appropriate theoretical model to describe the strain fields of the dislocation core.

Microstructure of spinel islands on the sapphire surface grown by ion implantation and annealing.

Fe ions were implanted into α-Al2O3 single crystals (sapphire) at energy of 50 keV and annealed in an oxidizing environment. Transmission electron microscopy (TEM) investigation indicated that Fe ions in the near surface region precipitated as α-Fe2O3 islands and spinel islands on the specimen surface, at the same time, Fe ions in the region away from the surface precipitated as α-Fe particles in the interior region of specimen. Two orientation relationships (ORs) between the spinel islands and sapphire substrate were discovered as follows: (111)spinel∥(0001)sapphire, [1 1 2¯]spinel∥[1 1 2¯ 0]sapphire and (1 1 2¯)spinel∥(0 0 0 1)sapphire, [1 1 1]spinel∥[1 1 2¯ 0]sapphire. The first OR was frequently observed in the spinel/sapphire system, however, the second OR has never been reported before. The interfaces between the spinel islands and sapphire substrate are a type-3 incoherent interface (i.e. low-index OR in at least one direction with an ill-matched low-index habit planes). The formation of spinel islands on the specimen surface can be attributed to the oxidizing atmosphere and the low accelerating voltage for ion implantation.

Orientation relationship between α-Fe precipitate and α-Al2O3 matrix in iron-implanted sapphire.

Fe ions were implanted into α-Al2O3 single crystals (sapphire) at room temperature and annealed in a reducing atmosphere. The orientation relationships (ORs) between α-Fe particles and sapphire matrix were investigated using transmission electron microscopy (TEM). All the α-Fe particles have the orientation relationship (OR) of (111)α-Fe||(0001)sapphire and [11¯0]α-Fe||[112¯0]sapphire with sapphire. This OR is predicted precisely by the coincidence of reciprocal lattice points (CRLP) method. The other OR of (110)α-Fe||(0001)sapphire and [111]α-Fe||[51¯4¯0]sapphire reported before is confirmed by the same method to be one of the secondary preferred orientation relationships in the α-Fe/sapphire system.

Effect of annealing on magnetic properties of Ni80Fe20 permalloy nanoparticles prepared by polyol method.

Ni80Fe20 permalloy nanoparticles with narrow size distribution and homogeneous composition have been prepared by the polyol processing at 180 degrees C for 2 h and their particle sizes can be tunable in the size range of 20-440 nm by proper addition of K2PtCI4 agent. X-ray diffraction results show that the NiFe nanoparticles are of face centered cubic structure. The addition of K2PtCl4 does not affect the composition of NiFe NPs but decreases the particle size remarkably. Both saturation magnetization and coercivity of the as-prepared NiFe nanoparticles decrease with decreasing particle size. Annealed at 280 degrees C, however, the saturation magnetization of various sized NiFe nanoparticles increases drastically and approaches to the bulk for the -440 nm NiFe particles, and a maximum coercivity (-270 Oe) happens at a critical size of -50 nm. The magnetic property dependency of these NiFe nanoparticles on annealing has been discussed by considering the surface chemistry.

In vitro dopaminergic neuroprotective and in vivo antiparkinsonian-like effects of Delta 3,2-hydroxybakuchiol isolated from Psoralea corylifolia (L.).

Cocktail recipes containing Psoralea corylifolia seeds (PCS) are used to empirically treat Parkinson disease. A PCS isolate Delta(3),2-hydroxybakuchiol (BU) can inhibit dopamine uptake in dopamine transporter (DAT) transfected Chinese hamster ovary (CHO) cells, and dopamine reuptake blockade may provide an alternative approach for ameliorating parkinsonism. Here, we assessed the potential dopaminergic neuroprotective, and antiparkinsonian-like activity of BU. BU sample size was increased by using a scale-up extraction paradigm. Pharmacologically, BU significantly protected SK-N-SH cells from 1-methyl-4-phenylpyridinium (MPP(+)) insult, produced striking inhibitory actions on dopamine/norepinephrine uptake and WIN35,428 binding in synaptosomes on in vivo administration, and significantly preventing poor performance on rotarod and dopaminergic loss in substantia nigra in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mice. BU acts by protecting dopaminergic neurons from MPP(+) injury and preventing against MPTP-induced behavioral and histological lesions in the Parkinson's disease (PD) model, possibly by inhibiting monoamine transporters. These findings suggest that BU could be meaningful in PD treatment.

Compounds from Kadsura ananosma.

The 18-(13-->12 beta)-abeo-lanostene triterpenoid acid, ananosic acid A (1), and the dibenzocyclooctadiene lignan, ananosin A (2), were isolated from the stem bark of Kadsura ananosma. Their structures were elucidated by extensive spectral studies and the structure of 1 was confirmed by single crystal X-ray diffraction analysis.

Cytotoxic mono-tetrahydrofuran ring acetogenins from leaves of Annona montana.

Further studies on leaves of Annona montana led to isolation of one iso-acetogenin, montanacin G, three pairs of acetogenins, montanacin H-J and 34-epi-montanacin H-J, together with four known acetogenins, gigantetrocins A and B, annonacin and cis-annonacin. Montanacin G belongs to the iso-acetogenin group with a terminal 2,4-trans-ketolactone unit. Montanacin H-J and 34-epi-montanacin H-J contain the rare gamma-hydroxy-gamma-methyl-gamma-lactone moiety. The cytotoxic activities of these compounds, together with previously reported acetogenins, montanacins B and C, were examined against Meth-A and LLC tumor cell lines in vitro.

Three diterpene glucosides and a diphenylamine derivative from Pieris formosa.

Three new diterpenoids, pierisformosides G-I (1-3) and a diphenylamine derivative 4 have been isolated from the ethanol extract of Pieris formosa leaves, compound 1 being a new type seco-ring-A kaurane diterpene glucoside. Their structures were elucidated with the aid of NMR spectroscopy including two-dimensional-NMR techniques.

Cytotoxic oxoisoaporphine alkaloids from Menispermum dauricum.

Four new oxoisoaporphine alkaloids, daurioxoisoporphines A-D (1-4), were isolated from the rhizomes of Menispermum dauricum. The structures of these alkaloids were established by spectroscopic methods. The cytotoxic evaluation of 1 and 2 is reported against four cancer cell lines.

Triterpenoid acids from Schisandra propinqua with cytotoxic effect on rat luteal cells and human decidual cells in vitro.

Three triterpenoid acids, nigranoic acid (1), manwuweizic acid (2), schisandronic acid (3), and other four compounds were isolated from the stems of Schisandra propinqua. Compounds 1 and 2 showed significant cytotoxic effect against human decidual cells and rat luteal cells in vitro.

Constituents from the leaves of Rhododendron latoucheae.

Twelve constituents from Rhododendron latoucheae were isolated. Among them, compounds 1 and 2, named rhodolatouside A and B, respectively, are new iridoids.

[Studies on chemical constituents from Euphorbia fischeriana Steud].

OBJECTIVE: To study the chemical constituents of ethanol extract from dried roots of Euphorbia fischeriana. METHOD: Compounds were separated by column chromatography with silca gel and elucidated by chemical evidence and spectral analysis. RESULT: Isobauerenyl acetate, beta-amyrin acetate, 24-methylenecycloartenone,octacosyl ferulate and 2,4-dihydroxy-6-methoxy-3-methyl acetophenone were isolated and elucidated. CONCLUSION: All the compounds were isolated from the plant for the first time.

New biflavanones and bioactive compounds from Stellera chamaejasme L.

AIM: To study the chemical constituents of the root of Stellera chamaejasme L. METHODS: Various column chromatographies on silica gel and RP-18 were employed for isolation and purification. Structures of compounds were elucidated by spectral analysis. RESULTS: Eight lignans and three biflavonoids possessing a C-3/C-3" linkage were isolated. They are ruixianglangdusu A (1) and B (2), 4',4'",5,5",7,7"-hexahydroxy-3,3"-biflavone (3), (+)-kusunokinin (4), lirioresinol-B (5), magnolenin C (6), (-)-pinoresinol monomethyl ether (7), (-)-pinoresinol (8), (+)-matairesinol (9), isohinokinin (10) and (-)-eudesmin (11). CONCLUSION: Compounds 1 and 2 are new biflavanones, 1 is enantiomeric to known chamaejasmenin C, 4, 6, 8, 9, 10 and 11 were isolated from this plant for the first time, and 7 was isolated from natural resources for the first time. In vitro bioassays showed that 3 and 8 exhibited antibacterial activity, and 1, 2, 9 and 11 exhibited immunomodulatory activity.

[Studies on chemical constituents of Schisandra propinqua (Wall.) Hook. f. et Thoms].

OBJECTIVE: To isolate and characterize compounds from the stems of Schisandra propinqua. METHOD: Extracting with solvent, isolating by column chromatography and identifying by the spectroscopic methods. RESULT: Six dibenzocyclooctadiene lignans were isolated and identified as tigloylgomisin P(1), angeloylgomisin O(2), angeloylisogomisin O(3), kadsulignan L(4), (+/-) 5,8-epoxyl-6, 7-dimethyl-2',3',2",3"-dimethylenedioxy-4', 1"-dimethyl-1,2:3,4-dibenzo-1, 3-cyclooctadiene(5) and wuweizisu C(6). CONCLUSION: Compounds 4 and 5 were the first two dibenzocyclooctadiene lignans with an 6,9-epoxy bridge cycle discovered in the genus Schisandra. The others were originally isolated from S. propinqua.

[Studies on chemical constituents of Stellera chamejasma L].

OBJECTIVE: Isolate and identify the bioactive compounds from the root of Stellera chamejasma. METHOD: The compounds were extracted with solvents, isolated by column chromatography and identified by spectroscopic methods. RESULT: Seven compounds were isolated and identified as umbelliferone(1); daphnoretin (2); 2,6-dimethoxyl p-benzoquinone(3); (-)-eudesmin(4); (+)-matairesinol(5); lirioresinol B(6) and daucosterol(7). CONCLUSION: Compounds 3, 4 and 5 were isolated from the plant for the first time.

The heterocyclic ring fission and dehydroxylation of catechins and related compounds by Eubacterium sp. strain SDG-2, a human intestinal bacterium.

A human intestinal bacterium, Eubacterium (E.) sp. strain SDG-2, was tested for its ability to metabolize various (3R)- and (3S)-flavan-3-ols and their 3-O-gallates. This bacterium cleaved the C-ring of (3R)- and (3S)-flavan-3-ols to give 1,3-diphenylpropan-2-ol derivatives, but not their 3-O-gallates. Furthermore, E. sp. strain SDG-2 had the ability of p-dehydroxylation in the B-ring of (3R)-flavan-3-ols, such as (-)-catechin, (-)-epicatechin, (-)-gallocatechin and (-)-epigallocatechin, but not of (3S)-flavan-3-ols, such as (+)-catechin and (+)-epicatechin.

A new bicoumarin from Stellera chamaejasme L.

Thirteen compounds were isolated from roots of Stellera chamaejasme L. (Thymelaeaceae). They are 3-sitosterol (2), simplexin (3), pimelea factor P2 (4), daucosterol (5), (+)-3-hydroxy-1,5-diphenyl-1-pentanone (6), 4-ethoxy-benzoic acid (7), 2,4,6-Trimethoxy-benzoic acid (8), (+)-afzelechin (9), fumaric acid (10), N,N-dimethyl-L-aspartic acid (11), umbelliferone (12), daphniretin (13) and a novel bicoumarin named bicoumastechamin (1). Among the known compounds, 7, 8, 9, 10 and 11 were first isolated from this plant, and 6 was first isolated from the natural resources. Their structures have been elucidated on the basis of spectral data. In vitro bioassays showed that 4 inhibited cancer cell growth, 13 exhibited immunomodulatory activity, and 6 exhibited both immunomodulatory and anti-tumor activity.

Human intestinal bacteria capable of transforming secoisolariciresinol diglucoside to mammalian lignans, enterodiol and enterolactone.

Seven metabolites were isolated after anaerobic incubation of secoisolariciresinol diglucoside (1) with a human fecal suspension. They were identified as (-)-secoisolariciresinol (2), 3-demethyl-(-)-secoisolariciresinol (3), 2-(3-hydroxybenzyl)-3-(4-hydroxy-3-methoxybenzyl)butane-1,4-diol (4), didemethylsecoisolariciresinol (5), 2(3-hydroxybenzyl)-3-(3,4-dihydroxybenzyl)butane-1,4-diol (6), enterodiol (7) and enterolactone (8). Furthermore, two bacterial strains, Peptostreptococcus sp. SDG-1 and Eubacterium sp. SDG-2, responsible for the transformation of 1 to a mammalian lignan 7, were isolated from a human fecal suspension. The former transformed 2 to 3 and 5, as well as 4 to 6, and the latter transformed 5 to 6 and 7.

Diterpene glucosides from Pieris formosa.

Five diterpene glucosides, pierisformosides B-F were isolated from Pieris formosa D. Don (Ericaceae). Their structures were elucidated on the basis of spectral analysis. including 1H-1H COSY, 13C-1H COSY, HMBC and NOESY experiments.

Diterpenoids from the fruits of Rhododendron molle.

Four new diterpenoids, rhodomolleins XV (1), XVI (2), XVII (3), and XVIII (4), together with three known diterpenoids, kalmanol and rhodojaponins III and VI, were isolated from the dried ripe fruits of Rhododendron molle. Their structures were elucidated on the basis of spectroscopic data interpretation.