In the title complex, C8H7N3O, the C—O [1.369 (2) and 1.364 (3) Å] and C=N [1.285 (3) and 1.289 (3) Å] bond lengths in the oxadiazole ring are each almost identical within systematic errors, although different substituents are attached to the ring. The phenyl ring is inclined to the planar oxadiazole ring [r.m.s. deviation 0.002 Å] by 13.42 (18)°. In the crystal, molecules are linked via N—H⋯N hydrogen bonds, forming double-stranded chains propagating along [010].

In the crystal structure of the title compound, C9H9N3O, adjacent mol­ecules are linked through N—H⋯N hydrogen bonds into a three-dimensional network.

The structure of Ba5Cl4(H2O)8(PVO5)8 consists of alternating anionic oxovanadium phosphate (VPO5) and cationic barium chloride hydrate, Ba5Cl4(H2O)8, layers. These layers are linked through Ba—O bonds, generating a three-dimensional framework.

The novel hydro­thermally synthesized title compound, penta­barium tetra­chloride octa­hydrate octa­kis(oxovanadium phosphate), Ba5Cl4(H2O)8(VPO5)8, crystallizes in the ortho­­rhom­bic space group Cmca with a unit cell containing four formula units. Two Ba2+ cations, two Cl− anions and the O atoms of four water mol­ecules are situated on the (100) mirror plane, while the third independent Ba2+ cation is on the inter­section of the (100) plane and the twofold axis parallel to a. Two phosphate P atoms are on twofold axes, while the remaining independent P atom and both V atoms are in general positions. The structure is characterized by two kinds of layers, namely anionic oxovanadium phosphate (VPO5), composed of corner-sharing VO5 square pyramids and PO4 tetra­hedra, and cationic barium chloride hydrate clusters, Ba5Cl4(H2O)8, composed of three Ba2+ cations linked by bridging chloride anions. The layers are connected by Ba—O bonds to generate a three-dimensional structure.

Background

Catch-up growth after food restriction (CUGFR) is characterized by a significant change in food intake which could theoretically lead to the change in glucagon-like peptide-1 (GLP-1) secretion that consequently results in altered functions of pancreatic islets.

Methods

Experimental rats were divided into two groups. Rats in CUGFR group were put on food-restriction for 4 weeks, and then allowed full access to food for 0, 2, 4 weeks respectively while rats in the control group were offered ad libitum access to food. Plasma glucose, insulin and GLP-1 level during OGTT were measured in all the rats. Moreover, morphology of intestinal mucosa, number of L cells, beta cell mass, incretin effect and the expression of GLP-1 receptor (GLP-1R) gene in the islets were also determined.

Results

The size of pancreatic islets, insulin concentration, plasma GLP-1 concentration, incretin effect, villus height-to-crypt depth ratio and L cells were all significantly decreased in CUGFR group at the end of a 4-week food-restriction period as compared with the controls. Insulin concentration and the villus height-to-crypt depth ratio were increased and finally exceeded the level of the control group over a 4-week catch-up period. Nevertheless, at the conclusion of the study, islet size, L cells number, plasma GLP-1 concentration and incretin effect increased but failed to reach the levels of the controls.

Conclusion

CUGFR decreases incretin effect and disturbs the entero-insular axis partially by decreasing GLP-1 concentration, which might be responsible for the increased risk of metabolic disorder during CUGFR.

The title borophosphate LiNi(H2O)2[BP2O8]·H2O was synthesized under hydro­thermal conditions. The crystal structure is isotypic with the Mg analogue and features helical [BP2O8]3− borophosphate ribbons, constructed by BO4 (2 symmetry) and PO4 tetra­hedra. The borate groups share all their oxygen apices with adjacent phosphate tetra­hedra. The ribbons are connected via Ni2+ cations that are located on twofold rotation axes. The cations have a slightly distorted octa­hedral oxygen coordination by four O atoms from the anion and by two water mol­ecules. The voids within the helices are occupied by Li+ cations, likewise located on twofold rotation axes, in an irregular environment of five O atoms. The structure is stabilized by O—H⋯O hydrogen bonds between coordinated or uncoordinated water mol­ecules and O atoms that are part of the helices.

The open-framework alkaline-earth metal borophosphate, lithium dicopper(II) borophosphate dihydroxide, LiCu2BP2O8(OH)2, was synthesized hydro­thermally. Its structure may be regarded as a layer formed via BO4 and PO4 tetra­hedra bonding together with distorted CuO6 and LiO6 octa­hedral units. Each P atom is connected to B, Li and Cu atoms through a bridging O atom. The B atom lies on a crystallographic twofold axis and the Li atom lies on a center of symmetry. The two metal centers are connected to each other by Cu—O—Li bonds.

The title salt, diaquatetra­manganese(II) oxalate bis[ortho­phos­phate(V)], Mn4(C2O4)(PO4)2(H2O)2, was synthesized hydro­thermally and displays a three-dimensional framework structure. The asymmetric unit consists of two different MnII centers, half of an oxalate anion, a phosphate group and a coordinated water mol­ecule. A crystallographic inversion center is located at the mid-point of the oxalate C—C bond. The distorted octa­hedral MnO6 and the tetra­gonal pyramidal MnO5 centers are linked through bridging oxalate and phosphate groups. The water mol­ecule also has a weaker bonding contact to the five-coordinate Mn atom, which consequently exhibits a distorted octa­hedral geometry and also bridges the independent Mn atoms. The water mol­ecule is a donor for intra- and inter­molecular O—H⋯O hydrogen bonds.