Multifunctional uranyl hybrid materials: structural diversities as a function of pH, luminescence with potential nitrobenzene sensing, and photoelectric behavior as p-type semiconductors.

A series of uranyl-organic frameworks (UOFs), {[(UO2)2(H2TTHA)(H2O)]·4,4'-bipy·2H2O}n (1), {[(UO2)3(TTHA)(H2O)3]}n (2), and {[(UO2)5(TTHA) (HTTHA)(H2O)3]·H3O}n (3), have been obtained by the hydrothermal reaction of uranyl acetate with a flexible hexapodal ligand (1,3,5-triazine-2,4,6-triamine hexaacetic acid, H6TTHA). These compounds exhibited three distinct 3D self-assembly architectures as a function of pH by single-crystal structural analysis, although the used ligand was the same in each reaction. Surprisingly, all of the coordination modes of the H6TTHA ligand in this work are first discovered. Furthermore, the photoluminescent results showed that these compounds displayed high-sensitivity luminescent sensing functions for nitrobenzene. Additionally, the surface photovoltage spectroscopy and electric-field-induced surface photovoltage spectroscopy showed that compounds 1-3 could behave as p-type semiconductors.

Photoluminescence enhancement in Yb(3+):Er(3+)co-doped eutectic Al(2)O(3): SiO(2) thin films by 980nm excitation.

Si nanocrystals (nc-Si) are addressed in the eutectic Al(2)O(3):SiO(2) thin films co-doped with Er(3+) and Yb(3+) by the laser-induced crystallization (LIC). The thin films are originally synthesized on a silica-on-silicon (SOS) substrate by the microwave electron cyclotron resonance (MW-ECR) plasma source enhanced RF sputtering. Raman spectroscopy has revealed that the strong crystallization occurs with the emergence of the nc-Si in the eutectic Al(2)O(3): SiO(2) layer during the liquid phase transformation. The dual wavelength energy transfer mechanism at 800nm and 980nm induced by 980nm excitation in nc-Si and Yb sensitized Er doped system has been proposed and demonstrated. A tenfold photoluminescence enhancement has been obtained from this mechanism.

proBDNF Attenuates Hippocampal Neurogenesis and Induces Learning and Memory Deficits in Aged Mice.

Mature brain-derived neurotrophic factor has shown promotive effect on neural cells in rodents, including neural proliferation, differentiation, survival, and synaptic formation. Conversely, the precursor of brain-derived neurotrophic factor (proBDNF) has been emerging as a differing protein against its mature form, for its critical role in aging process and neurodegenerative diseases. In the present study, we investigated the role of proBDNF in neurogenesis in the hippocampal dentate gyrus of aged mice and examined the changes in mice learning and memory functions. The results showed that the newborn cells in the hippocampus revealed a significant decline in proBDNF-treated group compared with bovine serum albumin group, but an elevated level in anti-proBDNF group. During the maturation period, no significant change was observed in the proportions of phenotype of the newborn cells among the three groups. In water maze, proBDNF-treated mice had poorer scores in place navigation test and probe test, compared with those from any other group. Thus, we conclude that proBDNF attenuates neurogenesis in the hippocampus and induces the deficits in learning and memory functions of aged mice.

Synthesis, crystal structure, photoluminescence property of a series of 3d-4f coordination supramolecular complexes.

A series of 3d-4f heterobinuclear complexes were constructed by employing the 2,2'-bipy (2,2'-bipy=2,2'-bipyridine) ligand and corresponding metal ions (M(II)/Ln(III), M=Co(II), Cu(II) and Zn(II); Ln(III)=Nd(III), Sm(III), Eu(III) and Tb(III)). Elemental analyses, IR, UV-vis-NIR spectra, PXRD and single crystal X-ray diffraction analysis reveal that complexes 1-4, 5-8, and 9-12 are isomorphous, respectively. The zero-dimensional structures are further connected to 2D or 3D supramolecular network structures via extensive intermolecular hydrogen bonds. Luminescence studies for the heterobinuclear complexes containing Sm(III), Eu(III) and Tb(III) reveal that the chromophoric composed of Zn(II)/L may efficiently sensitize the luminescence of the rare earth cations which acts as an antenna, whereas the existence of Cu(II) leads to the quenching of the luminescence of Ln(III) ions.

Hierarchically clustering to 1,033 genes differentially expressed in mouse superior colliculus in the courses of optic nerve development and injury.

Tempo spatially specific expression of many development-related genes is the molecular basis for the formation of the central nervous system (CNS), especially those genes regulating the proliferation, differentiation, migration, axon growth, and orientation of nerve cells. The development-related genes are usually prominent during the embryonic and newborn stages, but rarely express during the adulthood. These genes are believed to be suitable target genes for promoting CNS regeneration, despite majority of which remains unknown. Hence, the aim of this study was to screen development-related genes which might contribute to CNS regeneration. In this study, 1,033 differentially-expressed genes of superior colliculus in the courses of mouse optic nerve development and injury, as previously identified by cDNA microarrays, were hierarchically clustered to display expression pattern of each gene and reveal the relationships among these genes, and infer the functions of some unknown genes based on function-identified genes with the similar expression patterns. Consequently, the expression patterns of 1,033 candidate genes were revealed at eight time points during optic nerve development or injury. According to the similarity among gene expression patterns, 1,033 genes were divided into seven groups. The potential function of genes in each group was inferred on the basis of the dynamic trend for mean gene expression values. Moreover, the expression patterns of six function-unidentified genes were extremely similar to that of the ptn gene which could promote and guide axonal extension. Therefore, these six genes are temporally regarded as candidate genes related to axon growth and guidance. The results may help to better understand the roles of function-identified genes in the stages of CNS development and injury, and offer useful clues to evaluate the functions of hundreds of unidentified genes.

[Evaluation of the protection conferred by several avian infectious bronchitis attenuated vaccines against the field strain CK/CH/LDL/97 I in China].

The entire S1 protein gene of five infectious bronchitis (IB) vaccine strains (JAAS, IBN, Jilin, J9, H120) used in China were compared with that of the IB field isolate CK/CH/LDL/97 I present in China. The nucleotide and deduced amino acid similarities between the five IB vaccine strains and the field strain, CK/CH/LDL/97 I, were not more than 76.4% and 78.7%, respectively. Phylogenetic analysis based on the S1 gene showed that the vaccine strains and the field strain belonged to different clusters and had larger evolutionary distances, indicating that they were of different genotypes. The five vaccine strains were used for protection test against challenge of the field isolate CK/CH/LDL/97 I. The chickens inoculated with five vaccine strains showed morbidity as high as 30%-100% after challenged with the CK/CH/ LDL/97 I strain. The organ samples at 5 days post challenge showed that the viral detection rates were 50%-90% and 10%-30% for trachea and kidney, respectively. The live attenuated vaccines only provided partial protection to the vaccinated chickens against heterologous IBV infection, CK/CH/LDL/97 I.

Repair of spinal cord injury by neural stem cells modified with BDNF gene in rats.

Objective To explore repair of spinal cord injury by neural stem cells (NSCs) modified with brain derived neurotrophic factor (BDNF) gene (BDNF-NSCs) in rats. Methods Neural stem cells modified with BDNF gene were transplanted into the complete transection site of spinal cord at the lumbar 4 (L4) level in rats. Motor function of rats' hind limbs was observed and HE and X-gal immunocytochemical staining, in situ hybridization, and retrograde HRP tracing were also performed. Results BDNF-NSCs survived and integrated well with host spinal cord. In the transplant group, some X-gal positive, NF-200 positive, GFAP positive, BDNF positive, and BDNF mRNA positive cells, and many NF-200 positive nerve fibers were observed in the injury site. Retrograde HRP tracing through sciatic nerve showed some HRP positive cells and nerve fibers near the rostral side of the injury one month after transplant and with time, they increased in number. Examinations on rats' motor function and behavior demonstrated that motor function of rats' hind limbs improved better in the transplant group than the injury group. Conclusion BDNF-NSCs can survive, differentiate, and partially integrate with host spinal cord, and they significantly ameliorate rats ' motor function of hind limbs, indicating their promising role in repairing spinal cord injury.