The association between the microbes in the tracheobronchial aspirate fluid and bronchopulmonary dysplasia in preterm infants.

OBJECTIVE: The study aimed to evaluate the association between microbes in the lower respiratory tract (LRT) and the srisk for severe bronchopulmonary dysplasia (sBPD) in premature infants. METHODS: We conducted a retrospective, single-center study of preterm infants who were admitted to the neonatal intensive care unit (NICU) of Southern Medical University Affiliated Maternal & Child Health Hospital of Foshan, China, between January 2015 and December 2017. The microbes in the LRT were screened by using tracheobronchial aspirate fluid (TAF) culture. RESULTS: One hundred and fifty-five infants were included in the analysis. Among 155 infants, 41 were diagnosed with sBPD, and 114 were diagnosed without sBPD. There were significant differences between infants with and without sBPD in regard to birth weight (BW), gestational age (GA), the duration of endotracheal ventilation and supplemental oxygen. The incidence of retinopathy (ROP) and sepsis was higher in the sBPD infants than in the infants without sBPD. There was a difference in the detection rate of Gram-negative bacteria (GNB) between the two groups. Stenotrophomonas maltophilia and Klebsiella pneumoniae were mainly detected in TAF. CONCLUSIONS: The LRT microbes were different between infants with and without sBPD, and GNB is more frequently detected in sBPD infants.

First examples of extended structures based on {PMo(12)Sb(2)O(40)} polyoxoanions.

Three novel heteropolyanions [PMo(12)Sb(2)O(40)][Cu(enMe)(2)].4H(2)O (), [PMo(12)Sb(2)O(40)][Ni(enMe)(2)].4H(2)O (2) and [PMo(12)Sb(2)O(40)][Cu(en)(2)].H(3)O.H(2)O (3) (enMe = 1,2-diaminopropane, en = ethylene diamine) have been synthesized and characterized by IR spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analyses and elemental analyses. Single-crystal X-ray diffraction analyses reveal that these three compounds represent the first examples of compounds based on the novel polyoxoanion {PMo(12)Sb(2)O(40)} and different transition metal coordination complexes. 1 and 2 are isostructural and both exhibit novel 1-D structures. In contrast to 1 and 2, 3 exhibits a substantially distinct novel 1-D structure. In addition, 3 is the first example of an extended structure constructed from polyoxoanions and Cu(+) transition metal coordination complexes.

[hVEGF siRNA inhibits initial growth of A549 tumor cells in nude mice and angiogenesis on CAM assay].

OBJECTIVE: To investigate the effect of small interfering RNA (siRNA) targeting human vascular endothelial growth factor (hVEGF) on A549 cell growth in nude mice and angiogenesis on chorioallantoic membrane (CAM) assay. METHODS: Three pairs of hVEGF siRNA-plasmid and non-silencing-plasmid were constructed, and transfected into A549 cells through lipofectamine 2000, respectively. The most effective pair of hVEGF siRNA-plasmid was selected by ELISA and real-time RT-PCR. A549 cells transfected with selected hVEGF siRNA- plasmid, A549 cells transfected with non-silencing-plasmid and A549 cells without transfection were inoculated into nude mice, respectively. Chick embryos were randomly divided into four groups and CAM was treated by different solutions for 48 h: culture media DMEM as negative control group,un-transfected A549 cell culture supernatants as positive control group, hVEGF siRNA A549 cell culture supernatants as hVEGF siRNA group and nonsilencing siRNA A549 cell culture supernatants as non-silencing siRNA group. The CAMs were harvested on d12 for microscopic assays. RESULT: Compared with control group, hVEGF siRNA-plasmid induced 48% reduction in hVEGF secretion by A549 cells accompanied by 70% reduction in hVEGF mRNA. Compared with non-silencing siRNA group, the mean tumor volume of murine xenograft was reduced by 58% in hVEGF siRNA group; time for xenografts growing to 50 mm(3)was delayed by 5.4 d. hVEGF contents in xenograft were reduced by 54%; but mean doubling time of tumors and the growth rate of tumors were not significantly reduced. In CAM assays, hVEGF content was zero in negative group, and in hVEGF siRNA group that was 40%-44% of non-silencing siRNA group or positive group; vessels branch points of CAM in hVEGF siRNA group or non-silencing siRNA group or positive group were increased by 45%-55% compared with negative group; total vessel length of CAM in hVEGF siRNA group was increased by 53% compared with negative group, while in non-silencing siRNA group or positive group that was increased by 97% or 99%. Compared with negative control group, the proliferation of microvessels was increased when cell culture supernatant with hVEGF was added in hVEGF siRNA group, significant proliferated vessels were observed in non-silencing siRNA group or positive group. CONCLUSION: A plasmid-mediated hVEGF siRNA has been constructed and verified, which can effectively downregulate the expression of hVEGF in human A549 cells, resulting in the inhibition of angiogenesis. hVEGF siRNA can delay initial growth of A549 tumor xenograft but not reduce the growth rate.

{Bis[2-(diphenyl-phosphino)phen-yl] ether-κP:P'}(dimethyl 2,2'-biphenyl-4,4'-dicarboxyl-ate-κN:N')copper(I) hexa-fluorido-phosphate acetonitrile solvate.

In the title compound, [Cu(C(14)H(12)N(2)O(4))(C(36)H(28)OP(2))]PF(6)·CH(3)CN, the Cu(I) ion is coordinated by two N atoms from the dimethyl 2,2'-biphenyl-4,4'-dicarboxyl-ate ligand and two P atoms from the bis-[2-(diphenyl-phosphino)phen-yl] ether ligand in a distorted tetra-hedral environment. In the cation, the short distance of 3.870 (4) Šbetween the centroids of the benzene and phenyl rings suggests the existence of intra-molecular π-π inter-actions.

Synthesis and characterization of a novel POM compound containing two different layers stacked alternately.

A novel POM compound containing the first Sb bicapped Keggin anion {SiMo(12)O(40)Sb(2)} and two different layers constructed from these anions stacked alternately has already been hydrothermally synthesized.

[Crystal structures and luminescence property of d10 transition metal complexes].

Five Zn( [II)) and Cd(II) coordination complexes, [Zn(NA)2 (H2O)4](1), [Zn(INA)2 (H2O)4](2), [Zn(2,2'-bi-py)2 (SCN)2](3), [Cd(INA)2 (H2O)4](4) and [Cd(phen)2(NO3)](5) (HNA=nicotinic acid, HINA=isonicotinic acid, 2, 2'-bipy=2,2'-bipyridine, phen=1,10-phenanthroline), were synthesized through constant temperature magnetic stirrer or hydrothermal method, and their single-crystal structures were determined by X-ray diffraction. The authors measured the IR, UV-Vis-NIR and fluorescence spectra of the complexes and analyzed their photophysical properties. At room temperature in the solid state the five complexes can show strong fluorescence, i.e., lamdamax(em)=362 nm (lamda(ex)=330 nm), (1); lamdamax(em)=424 nm (lamda(ex)=330 nm), (2); lamdamax(em)=442 nm (lamda(ex)=380 nm), (3); lamdamax(em)=424 nm (lamda(ex)=330 nm), (4); lamda(em max)=456 nm (lamda(ex)=360 nm), (5), and complex (5) can emit phosphorescence upon excitation at 360 nm (lamdamax (pl)=546 nm, tau=10 ms). But the organic ligands are different, which lead to the luminescence property of complexes originating from different charge transfer. Compared with the relevant ligands (lamdamax (em)=380 nm, HNA; lamda(em max)=541 nm, 2,2'-bipy), the fluorescence emissions of complex (1) and (3) show a blue-shift which mainly comes from the ILCT (intraligand charge transfer) and at the same time exists L-->M(4S) transfer. The emissions of complex (2) and (4) come from LMCT (ligand-to-metal charge transfer) and show red-shift compared to that of free ligand (lamdamax(em)=337 nm, HINA). For complex (5), the appearance and position of its emission are different from those of the ligand (lamdamax(em)=381 nm, phen), which is attributed to LLCT (ligand-to-ligand charge transfer) and LMCT.

2,10-Dibromo-6,6-dimethyl-dibenzo[d,f][1,3]dioxepine.

In the crystal structure of the title compound, C(15)H(12)Br(2)O(2), which was synthesized from 2,10-dibromo-2,2'-dihydroxy-biphenyl and 2,2-dimethoxy-propane, the aromatic rings are twisted by 35 (1)°. The heterocyclic ring exhibits a twisted conformation.

2,2'-Bi[6,6'-dimethyl-dibenzo[d,f][1,3]dioxepine].

The title compound, C(30)H(26)O(4), is a dimer of 6,6'-dimethyl-dibenzo[d,f][1,3]dioxepine linked by formation of a C-C bond in the para position with respect to one O atom. The dimer is arranged around an inversion centre. As is usually observed in related compounds, the dibenzo group is twisted, the two benzene rings making a dihedral angle of 41.56 (9)°. The seven-membered ring exhibits a twisted conformation.

2,10-Dibromo-6-isobutyl-6-methyl-dibenzo[d,f][1,3]dioxepine.

In the crystal structure of the title compound, C(18)H(18)Br(2)O(2), the two benzene rings of the bridged biphenyl unit are twisted by 38.0 (1)°.

3,9-Dibromo-6,7-dihydro-5H-dibenzo[c,e]thiepine.

In the title mol-ecule, C(14)H(10)Br(2)S, the two benzene rings form a dihedral angle of 48.35 (14)°. The seven-membered ring adopts a boat conformation. In the crystal structure, mol-ecules are related by translation along the b axis and exhibit C-H⋯π inter-actions.

3,9-Dibromo-5,7-dihydro-dibenzo[c,e]oxepine.

The title compound, C(14)H(10)Br(2)O, is a biphenyl derivative containing a -CH(2)-O-CH(2)- bridge in the 2,2'-position. The compound displays a twisted conformation with the two benzene rings making a dihedral angle of 45.02 (5)°, while the central seven-membered ring is in a boat conformation. The mol-ecule lies on a crystallographic twofold axis of symmetry passing through the O atom and bis-ecting the 1,1' C-C bond.

Hydrothermal syntheses and structural characterizations of organic-inorganic hybrid materials of the M(II)-ligand/vanadium oxide system (M(II) = Mn(II), Cu(II) and Zn(II); ligand = 2,2'-bipyridine and 1,10-phenanthroline).

Three organic-inorganic hybrid compounds [Mn(bpy)V(bpy)V(3)O(11)] (bpy = 2,2'-bipyridine) (1), [Cu(bpy)V(2)O(6)] (2) and [Zn(phen)3][V(2)O(6)].10H(2)O (phen = 1,10-phenanthroline) (3) have been synthesized hydrothermally. Single crystal X-ray diffraction analyses revealed that compound 1 is the first example of bpy units coordinating to different transition metals in one molecule. Compound 2 is a new isomer of [Cu(bpy)V(2)O(6)] which was named the gamma-isomer by us. In compound 3, a 2-D water sheet with big holes filled by the "naked" [V(4)O(12)](4-) clusters is found.

Synthesis and characterization of binuclear molybdenum-polycarboxylate complexes with sulfur bridges.

A group of four binuclear sulfur-bridged molybdenum-polycarboxylato complexes with homocitrate, citrate, cysteine, ethylenediaminetetraacetate ligands, respectively, have been synthesized and characterized. These complexes were prepared in order to study the interaction of Mo and homocitrate in the FeMo-co of nitrogenases. In the structures of K4(NH4)2[Mo2O2S2(C6H4O7)2].10H2O (2), (NH4)2[Mo2O2S2(C3H5SNO2)2].5H2O (3) and (NH4)2[Mo2O2S2(C10H12N2O8)].3.5H2O (4), molybdenum (V) atom adopts a distorted octahedral arrangement through a terminal oxygen atom, two bridging sulfur atoms and three atoms from the ligand (hydroxyl, alpha-, beta-carboxylates, sulfide or amine). The coordination mode of homocitrate ligand in K5(NH4)[Mo2O2S2(C7H5O7)2].3H2O.CH3OH (1) has been proposed in a tridentate fashion via its hydroxyl and a pair of carboxylate groups (alpha-, beta-carboxylates). The electrochemical properties of these complexes have been discussed.

A new route for preparing coordination polymers from hydrothermal reactions involving in situ ligand synthesis.

The coordination chemistry of inorganic cobalt salt and the organic ligands H(4)bbh (=benzene-1,2,4,5-bihydrazide) and H(3)bcbh (=benzene-4-carboxylate-1,2-bihydrazide) generated through the in situ hydrothermal acylate reaction of H(4)bta (=benzene-1,2,4,5-tetracarboxylic acid) and H(3)btc (=benzene-1,2,4-tricarboxylic acid) with hydrazine hydrate, respectively, has been investigated. Three new coordination polymers were prepared and fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. The compound [Co(micro(3)-H(2)bbh)(phen)](n)() (1) (triclinic space group P with a = 9.762(4) A, b = 10.169(4) A, c = 11.143(4) A, alpha = 80.96(3) degrees, beta = 64.49(3) degrees, gamma = 71.88(3) degrees, Z = 2) was synthesized from the reaction of CoCl(2).6H(2)O, H(4)bta (=benzene-1,2,4,5-tetracarboxylic acid), N(2)H(4).H(2)O, phen (=1,10-phenanthroline) and H(2)O, and consists of one-dimensional double-chains. [Co(micro(4)-H(2)bbh)(H(2)O)(2)](n)() (2) (monoclinic space group P2(1)/c with a = 6.8687(5) A, b = 7.5943(6) A, c = 10.0401(6) A, beta = 95.250(4) degrees, Z = 2) was generated by the combination of CoCl(2).6H(2)O, H(4)bta, N(2)H(4).H(2)O, and H(2)O. It adopts a three-dimensional structural motif in the solid state with channels consisting of 20-numbered rings. [Co(micro(3)-Hbcbh)(bpy)](n)() (3) (monoclinic space group Cc with a = 9.9464(13) A, b = 23.685(5) A, c = 7.9491 (16) A, beta = 117.677(13) degrees, Z = 4) was obtained from the mixture of CoCl(2).6H(2)O, N(2)H(4).H(2)O, H(3)btc (=benzene-1,2,4-tricarboxylic acid), bpy (=2,2'-dipyridyl), and H(2)O, and features a two-dimensional plane. The results of magnetic research indicate that there exist antiferromagnetic interactions between Co centers in both compounds 1 and 2.

Two- and three-dimensional molecular organization of Schiff-base derivatives.

We have designed and synthesized a series of Schiff base derivatives, and studied their structural features in two-dimensional (2D) and three-dimensional (3D) states by combining scanning tunneling microscopy (STM) and X-ray diffraction experiments. The Schiff-base derivatives with short alkyl chains crystallize easily, which allows a detailed structural analysis by X-ray diffraction. Due to the strong adsorbate-substrate interactions, those bases with long alkyl chains easily form 2D assemblies on highly oriented pyrolytic graphite (HOPG). The STM images indicate also that the introduction of two methoxy groups into the molecule can change the structure of these 2D assemblies as a result of the increased steric hindrances, for example: the Schiff-base derivative, bearing both methoxy groups and C16H33 tails, forms 2D Moiré patterns, and an alignment of pairing Schiff-base molecules may be easily resolved. Conversely, the Schiff base derivative, bearing solely C16H33 tails, forms 2D non-Moiré patterns. It is demonstrated that the 3D structural features result from the compromise of intermolecular interactions of different molecular moieties. However, there is one more factor, which also governs the 2D structure: the adsorbate-substrate interaction. The 3D crystal structure may thus help to understand many factors involved in the formation of 2D structures, and would be helpful for designing new molecular assemblies with tailoring functions.