A DNA aptamer with high affinity and specificity for molecular recognition and targeting therapy of gastric cancer.

BACKGROUND: Aptamers have emerged as excellent molecular probes for cancer diagnosis and therapy. The aim of the current study was to determine the feasibility of using DNA aptamer cy-apt 20 developed by live cell-SELEX for detecting and targeting gastric cancer. METHODS: The specificity, sensitivity and biostability of cy-apt 20 in detecting gastric cancer were assessed by binding assay, cell fluorescence imaging, and in vivo tumor imaging in animal model in comparison with non-gastric cancers. RESULTS: Flow cytometric analysis showed that cy-apt 20 had higher than 78% of maximal binding rate to gastric cancer cells, much higher than that of non-gastric cancer cells. Cell fluorescence imaging and in vivo tumor imaging showed that the targeting recognition could be visualized by using minimal dose of fluorochrome labeled cy-apt 20. Meanwhile, strong fluorescence signals were detected and lasted for a period of time longer than 50 min in vitro and 240 min in vivo. The fluorescence intensities of gastric cancer were about seven folds in vitro and five folds of that of non-gastric cancers in vivo. CONCLUSION: Our study demonstrated that cy-apt 20 was an excellent molecular probe with high specificity and sensitivity and a certain degree of biostability for molecular recognition and targeting therapy of gastric cancer.

4,4'-(Ethene-1,2-di-yl)dipyridinium 4-[2-(pyridin-4-yl)ethen-yl]pyridinium octa-cyanidomolybdate(V) tetra-hydrate.

The crystal structure of the title compound, (C12H12N2)(C12H11N2)[Mo(CN)8]·4H2O, consists of 4,4'-(ethene-1,2-di-yl)dipyridinium and 4-[2-(pyridin-4-yl)ethen-yl]pyridinium cations disordered over the same site, an [Mo(CN)8](3-) anion and four water mol-ecules of crystallization. The eight-coordinate [Mo(CN)8](3-) unit exhibits a slightly distorted square-anti-prismatic geometry. In the structure, the cations (crystallographic symmetry, 2) and anions (crystallographic symmetry, 222) are arranged alternately by N-H⋯O and O-H⋯N hydrogen bonds, forming layers parallel to the bc plane. These layers are further linked through O-H⋯N hydrogen bonds, generating a three-dimensional supra-molecular network.

Tris(3,4,7,8-tetra-methyl-1,10-phenanthrolin-1-ium) hexa-cyanidocobaltate(III) penta-hydrate.

The structure of the title compound, (C16H17N2)3[Co(CN)6]·5H2O, consists of three 3,4,7,8-tetra-methyl-1,10-phenanthrolin-1-ium cations, a [Co(CN)6](3-) anion and five water mol-ecules of crystallization, one of which is disordered over two sets of sites in a 0.587 (15):0.413 (15) ratio. The [Co(CN)6](3-) anion exhibits an octa-hedral geometry. In the structure, cations and anions are linked alternatively through O-H⋯O, O-H⋯N, N-H⋯O and N-H⋯N hydrogen bonds, π-π inter-actions [centroid-centroid distances = 3.523 (2)-4.099 (2) Å] and van der Waals forces, forming a three-dimensional supra-molecular network.

Poly[[diaqua-hexa-µ-cyanido-cerium(III)ferrate(III)] dihydrate].

In the structure of the title complex, {[CeFe(CN)(6)(H(2)O)(2)]·2H(2)O}(n), the Ce(III) and Fe(III) atoms exhibit square anti-prismatic [CeN(6)(H(2)O)(2)] (site symmetry m2m) and octahedral [FeC(6)] (site symmetry 2/m) coordination geometries, respectively. The metal atoms are linked alternately through the cyanide groups, forming a three-dimensional framework in which the {Ce(2)Fe(2)(CN)(4)} puckered square unit is the basic building block. The crystal packing is enforced by O-H⋯O and O-H⋯N hydrogen bonds, including the uncoordinated water molecule which is located on a mirror plane.

Tris(1,10-phenanthrolin-1-ium) hexa-cyanidoferrate(III) ethanol monosolvate trihydrate.

The asymmetric unit of the title complex, (C(12)H(9)N(2))(3)[Fe(CN)(6)]·C(2)H(5)OH·3H(2)O, consists of two half [Fe(CN)(6)](3-) anions located on inversion centers, three 1,10-phenanthrolin-1-ium cations, [Hphen](+), an ethanol and three water solvent mol-ecules. The average Fe-C and C-N bond lengths are 1.942 (6) and 1.154 (3) Å, respectively, while the Fe-C-N angles deviate slightly from linearity with values ranging from 177.8 (2) to 179.7 (2)°. The Fe(III) atoms adopt a distorted octa-hedral geometry. All the species are linked through O-H⋯N, N-H⋯O and O-H⋯O hydrogen-bonding inter-actions, resulting in a three-dimensional supra-molecular network.

Tetra-aqua-tetra-kis-(4,4'-bipyridine dioxide-κO)terbium(III) octa-cyanidotungstate(V).

In the title compound, [Tb(C(10)H(8)N(2)O(2))(4)(H(2)O)(4)][W(CN)(8)], both metal atoms are eight-coordinated. The Tb(III) ion displays a dodeca-hedral geometry, while the W(v) ion exhibits a distorted square-anti-prismatic geometry. The Tb atoms are located on a special position of site symmetry -4, whereas the W atoms are located on a twofold rotation axis. The cations are linked by O-H⋯O hydrogen bonds. The title compound is isotypic with the corresponding and previously described Mo compound [Qian & Yuan (2011 ▶). Acta Cryst. E67, m845].

Tetra-aqua-tetra-kis-(4,4'-bipyridine dioxide-κO)terbium(III) octa-cyanido-molybdate(V).

In the title compound, [Tb(C(10)H(8)N(2)O(2))(4)(H(2)O)(4)][Mo(CN)(8)], both metal atoms are eight-coordinated. The Tb(III) atom displays a dodecahedral geometry, while the Mo(V) ion exhibits a distorted square-anti-prismatic geometry. The Tb atoms are located on a special position of site symmetry [Formula: see text], whereas the Mo atoms are located on a twofold rotation axis. The cations are linked by O-H⋯O hydrogen bonds.

Efficient synthetic strategy to construct three-dimensional 4f-5d networks using neutral two-dimensional layers as building blocks.

The reaction of neutral two-dimensional (2D) layer Tb(H(2)O)(5)W(CN)(8) with pyrazine in the acetonitrile solution has led to a 3D bimetallic complex, Tb(H(2)O)(4)(pyrazine)(0.5)W(CN)(8) (1). In the structure of 1, the eight-coordinated W center adopts a slightly distorted dodecahedron, while the Tb center exhibits a nine-coordinated slightly distorted tricapped trigonal prism. The Tb(3+) atoms and the [W(CN)(8)](3-) units are linked in alternating fashion in the ab crystallographic plane, resulting in an infinite 2D corrugated layers. The linear bis-monodentate pyrazine ligands acting as pillars link adjacent layers along the c axis to form an extended 3D open framework. The possible formation mechanism is proposed, and the temperature has played a crucial role for the formation of 1. Magnetic measurements revealed the presence of ferromagnetic interaction between Tb(III) and W(V) centers. 1 marks the first structural pattern using the neutral 2D layer as building block and the first 3D complex with Ln(III)-[W(V)(CN)](8) found in octacyanometallate-based system. Such a novel and effective building-block methodology will provide a new attractive path forward in developing functionalities of 3D 4f-5d system and may provide an opportunity to obtain 3D magnet in 4f-5d assembly.

Fabrication of Si Nanoparticles Encapsulated into Porous N-Doped Carbon for Superior Lithium Storage Performances.

To improve lithium storage performances of Si anode for lithium-ion batteries, Si nanoparticles encapsulated into porous N-doped carbon (Si@PNC) was devised and prepared by metal nitrate accelerated polymer blowing process. The Si@PNC composites have large specific surface area of 221.7 m² g-1 and possess a great deal of mesopores and micropores, which are attributed to the carbonization of PVP and etching metallic nanoparticles. As anode for lithium ion battery, the initial discharge capacity of Si@PNC composites is high to 1626 mA h g-1, and the specific capacity still retains 1030 mA h g-1 after 200 cycles at 200 mA g-1. Meanwhile, remarkably improved rate capability is achieved with an excellent reversible specific capacity of 375 mA h g-1 at 5.0 A g-1. The excellent lithium storage performances benefit from the unique porous core-shell structure of Si@PNC composites, which improve electroconductivity, reduce volume dilatation and accelerate lithium ion transmission.

A cyanide-bridged Fe(II)-Nd(III) bimetallic assembly with a one-dimensional ladder-like chain structure.

The title complex, catena-poly[[[(2,2'-bipyridine-1kappa(2)N,N')tris(methanol-2kappaO)(nitrato-2kappa(2)O,O')-mu-cyanido-1:2C:N-cyanido-1kappaC-iron(II)neodymium(III)]-di-mu-cyanido-1:2'C:N;2:1'N:C] methanol solvate], {[Fe(II)Nd(III)(CN)(4)(NO(3))(C(10)H(8)N(2))(CH(3)OH)(3)].CH(3)OH}(n), is made up of ladder-like one-dimensional chains oriented along the c axis. Each ladder consists of two strands based on alternating Fe(II) and Nd(III) centers connected by cyanide bridges. Furthermore, two such parallel chains are connected by additional cyanide cross-pieces (the ;rungs' of the ladder), which likewise connect Fe(II) and Nd(III) centers, such that each [Fe(CN)(4)(bipy)](2-) unit (bipy is 2,2'-bipyridine) coordinates with three Nd(III) centers and each Nd(III) center connects with three different [Fe(CN)(4)(bipy)](2-) units. In the complex, the iron(II) cation is six-coordinated with a distorted octahedral geometry and the neodymium(III) cation is eight-coordinated with a distorted dodecahedral environment.

Poly[bis-(dimethyl-ammonium) [bis-(dimethyl-amine-κN)tris-(µ(2)-terephthalato-κO:O)dizinc(II)] N,N-dimethyl-formamide disolvate hexa-hydrate].

The title compound, {(C(2)H(8)N)(2)[Zn(2)(C(8)H(4)O(4))(3)(C(2)H(7)N)(2)]·2C(3)H(7)NO·6H(2)O}(n), consists of two-dimensional non-inter-penetrated sheets with 6(3) topology, which are stacked together in an …ABAB… packing mode along the c axis. The distance between adjacent A and B sheets is ca 7.3 Å. In the structure, the Zn(II) center is coordinated by three O atoms from three terephthalate groups and one N atom from one dimethyl-amine ligand, adopting a distorted tetra-hedral geometry. All solvent water mol-ecules are disordered. In the structure, N-H⋯O and O-H⋯O hydrogen bonds are observed.

4,4'-Diazenediyldipyridinium 4-(4-pyridyldiazen-yl)pyridinium octa-cyanidotungstate(V) dihydrate.

The asymmetric unit of the title complex, (C(10)H(10)N(4))(C(10)H(9)N(4))[W(CN)(8)]·2H(2)O, contains two 4,4'-diazenediyldipyridinium, [H(2)(4,4'-azpy)](2+), two 4-(4-pyridyldiazen-yl)pyridinium, [H(4,4'-azpy)](+), cations, two [W(V)(CN)(8)](3-) anions, and four uncoordinated water mol-ecules. Each of the W centers is coordinated by eight CN groups in a slightly distorted square-anti-prismatic geometry. In the crystal structure, intra- and inter-molecular N-H⋯O, N-H⋯N and O-H⋯N hydrogen bonds link the cations and anions in an alternating fashion, forming a two-dimensional layered structure, in which they are further linked through the very weak π-π stacking inter-actions [shortest distance = 4.640 (2) Å] and van der Waals forces between adjacent layers, forming a three-dimensional supra-molecular network.

Poly[[(µ(2)-benzene-1,4-dicarboxyl-ato-κO,O:O,O)(µ(2)-di-4-pyridyldiazene-κN:N)cobalt(II)] N,N-dimethyl-formamide disolvate hemihydrate].

In the title compound, {[Co(C(8)H(4)O(4))(C(10)H(8)N(4))]·2C(3)H(7)NO·0.5H(2)O}(n), the Co(II) atom is six-coordinated by four O atoms from two benzene-1,4-dicarboxyl-ate (H(2)bdc(2-)) groups and two N atoms from two 4,4'-azopyridine (4,4'-azpy, or di-4-pyridyldiazene) ligands, leading to a distorted octa-hedral geometry. The structure consists of two-dimensional corrugated sheets with a 4(4) topology in an …ABAB… packing pattern stacking along the a axis. The separation of the adjacent corrugated sheets is ca. 8.561 (2)  Š(Co⋯Co distance) along the a axis. The uncoordinated water molecule is half-occupied. The crystal structure is stabilized by O-H⋯N and C-H⋯O hydrogen-bonding inter-actions.

Di-µ-cyanido-1:2κC:N,2:3κN:C-hexa-cyanido-1κC,3κC-tetra-kis(1,10-phenanthroline)-1κN,N';2κN,N';3κN,N'-1,3-dicobalt(III)-2-iron(II) tetra-hydrate.

The hydro-thermal reaction of CoCl(2)·6H(2)O, 1,10-phenanthroline (phen) and K(3)[Fe(CN)(6)] in deionized water yielded the title cyanide-bridged trinuclear cluster, [Co(2)Fe(CN)(8)(C(12)H(8)N(2))(4)]·4H(2)O or [{Co(III)(phen)(CN)(4)}(2){Fe(II)(phen)(2)}]·4H(2)O, which contains two Co(III) centers and one Fe(II) center linked by cyanide bridges. The combination of coordinative bonds, O-H⋯N and O-H⋯O hydrogen bonds and π-π stacking inter-actions [centroid-centroid distance = 3.630 (2) Å] results in the stabilization of a supra-molecular structure. All uncoordinated water molecules are disordered. Thermogravimetric analysis reveals that the title complex loses the four crystal water mol-ecules at about 333 K, then the anhydrous phase loses no further mass up to about 573 K, above which decomposition occurs.

4,4'-Diazenediyldipyridinium (4-pyridyldiazen-yl)pyridinium octa-cyanidomolyb-date(V) tetra-hydrate.

The structure of the title complex, (C(10)H(10)N(4))(C(10)H(9)N(4))[Mo(CN)(8)]·4H(2)O, consists of 4,4'-diazenediyldipyridinium and (4-pyridyldiazen-yl)pyridinium cations disordered over the same site, an [Mo(CN)(8)](3-) anion and four uncoordinated water mol-ecules. The cations (crystallographic symmetry, 2) and the [Mo(CN)(8)](3-) anion (crystallographic symmetry, 222) are arranged in an alternating fashion, forming a two-dimensional layered structure through hydrogen bonds. Hydrogen bonds, π-π stacking inter-actions (shortest distance = 4.7872 Å) and van der Waals forces between adjacent layers generate a three-dimensional supra-molecular structure.

Poly[bis[3,10-bis(2-hydroxyethyl)-1,3,5,8,10,12-hexa-azacyclo-tetra-deca-ne]tetra-µ-cyanido-tetracyanidodicopper(II)molybdenum(IV)] tetra-hydrate].

In the title complex, {[Cu(2)Mo(CN)(8)(C(12)H(30)N(6)O(2))(2)]·4H(2)O}(n), the polyhedron around Mo has site symmetry with a distorted square-antiprismatic shape, while the Cu atom (2 symmetry) is in a distorted axially elongated octa-hedral coordination environment. The uncoordinated water molecule is disordered over three sites with occupancies of 0.445 (7), 0.340 (7) and 0.215 (7). Mo and Cu atoms acting as basic components are connected by an Mo-CN-Cu-NC-Mo- linkage to form a distorted diamond-like network. Additional hydrogen bonding between the N-H groups and the water molecules stabilizes this arrangement.

Bis[tris-(ethane-1,2-diamine)nickel(II)] octa-cyanidomolybdate(IV) dihydrate.

The title complex, [Ni(II)(C(2)H(8)N(2))(3)](2)[Mo(IV)(CN)(8)]·2H(2)O, crystallized from a mixture of ethane-1,2-diamine (en), octa-cyano-molybdate(IV), [Mo(CN)(8)](4-), and the transition metal ion Ni(2+). In the crystal structure, the Mo polyhedron has a square-anti-prismatic shape, while the geometry around the Ni atom is distorted octa-hedral. The complex ions and water mol-ecules are linked by hydrogen bonds.

Tris[tris-(ethane-1,2-diamine)cobalt(II)] bis-[octa-cyanidomolybdate(V)] dihydrate.

In the title compound, [Co(II)(C(2)H(8)N(2))(3)](3)[Mo(V)(CN)(8)](2)·2H(2)O, N-H⋯N and N-H⋯O hydrogen-bonding inter-actions give rise to a three-dimensional network. In the crystal structure, each Mo polyhedron has a square-anti-prismatic shape, while the Co complexes show distorted octa-hedral geometry with an occupancy of 50%. One of the Co atoms resides on a crystallographic inversion centre.

Slow magnetic relaxation influenced by change of symmetry from ideal Ci to D3d in cobalt(ii)-based single-ion magnets.

The coordination geometries of the Co(ii) site in the two complexes [Co(imidazole)6][BPh4]2·0.3CH3CN (1) and [Co(imidazole)6][NO3]2 (2) were observed to display the ideal symmetries Ci and D3d, respectively. Both complexes were shown to be field-induced single-ion magnets. The effective energy barrier was found to decrease as the local symmetry changed from low-symmetry Ci to high-symmetry D3d.

[Morphological research on brain development and expression of vital cytokines in brain of human 6-8 week old embryo aborted for unexpected cause].

OBJECTIVE: To clarify the changes in cell proliferation, differentiation, apoptosis and in the expression of vital cytokines during development of 6-8 week old embryo, and hence provide the evidence for identifying the mechanisms of cell proliferation, differentiation, apoptosis during early developing human embryonic brain. METHODS: Human aborted embryos were obtained with the consents signed by the pregnant women with unexpected abortions in gestation of 6-8 weeks. The histochemical SABC method and TUNEL Staining were employed to this research project. RESULTS: At 6 weeks, two telencephalons, diencephalon, mesencephalon, metencephalon, and myelencephalon have been formed, and from week 6 to 8, every cerebral vesicle has had three layer cells including germinal layer (GL), intermediate layer ( IL ), and marginal zone (MZ). At 6-7 weeks, TUNEL-labeled cells and PCNA-, Bcl-2-, Bax-, Fas-, Fas-L-, Rb- and P53-positive cells were all observed in the GL and IL of the five brain regions, positive deposition appeared in nuclei. At week 8, Fas- and Rb-positive cells were observed in the IL of the five brain regions, positive deposition appeared in cytoplasm and cell processes, and no changes in the distributions of TUNEL-labeled cells and positive cells regarding the other five factors. The expressions of the cytokines were in agreement with the occurrence of the neuronal proliferation and apoptosis temporally and in space. CONCLUSION: During development in early embryo brain, neural precursor cell proliferation and apoptosis occur simultaneously. Fas, FasL and Bax may be involved in the induction of cell apoptosis. Bcl-2 probably prevents the cell apoptosis and provides a survival signal for cells. Rb and P53 may play a critical role in monitoring and maintaining the normal neural precursor cell to proliferation and differentiation.