Bistable near field and bistable transmittance in 2D composite slab consisting of nonlocal core-Kerr shell inclusions.

We carry out a theoretical study on optical bistability of near field intensity and transmittance in two-dimensional nonlinear composite slab. This kind of 2D composite is composed of nonlocal metal/Kerr-type dielectric core-shell inclusions randomly embedded in the host medium, and we derivate the nonlinear relation between the field intensity in the shell of inclusions and the incident field intensity with self-consistent mean field approximation. Numerical demonstration has been performed to show the viable parameter space for the bistable near field. We show that nonlocality can provide broader region in geometric parameter space for bistable near field as well as bistable transmittance of the nonlocal composite slab compared to local case. Furthermore, we investigate the bistable transmittance in wavelength spectrum, and find that besides the input intensity, the wavelength operation could as well make the transmittance jump from a high value to a low one. This kind of self-tunable nano-composite slab might have potential application in optical switching devices.

Glutamate and GABA imbalance promotes neuronal apoptosis in hippocampus after stress.

BACKGROUND: People who experience traumatic events have an increased risk of post-traumatic stress disorder (PTSD). However, PTSD-related pathological changes in the hippocampus and prefrontal cortex remain poorly understood. MATERIAL AND METHODS: We investigated the effect of a PTSD-like animal model induced by severe stress. The experimental rats received 20 inescapable electric foot shocks in an enclosed box for a total of 6 times in 3 days. The physiological state (body weight and plasma corticosterone concentrations), emotion, cognitive behavior, brain morphology, apoptosis, and balance of gamma-aminobutyric acid (GABA) and glutamate in the hippocampus and prefrontal cortex were observed. Cell damages were examined with histological staining (HE, Nissl, and silver impregnation), while apoptosis was analyzed with flow cytometry using an Annexin V and propidium iodide (PI) binding and terminal deoxynucleotidyl transferase mediated-dUTP nick end labeling (TUNEL) method. RESULTS: In comparison with the sham litter-mates, the stressed rats showed decreased body weight, inhibition of hypothalamic-pituitary-adrenal (HPA) axis activation, increase in freezing response to trauma reminder, hypoactivity and anxiety-like behaviors in elevated plus maze and open field test, poor learning in Morris water maze, and shortened latency in hot-plate test. There were significant damages in the hippocampus but not in the prefrontal cortex. Imbalance between glutamate and GABA was more evident in the hippocampus than in the prefrontal cortex. CONCLUSIONS: These results suggest that neuronal apoptosis in the hippocampus after severe traumatic stress is related to the imbalance between glutamate and GABA. Such modifications may resemble the profound changes observed in PTSD patients.

Multi-response gelation based on the molecular assembly of Sudan I dye derivatives for phase selective gelators and chemosensors.

Sudan I dye-based smart low molecular weight gelators with/without a perfluoroalkyl group have been successfully synthesized and characterized by rheological measurements, scanning electron microscopy (SEM), IR, and NMR spectroscopies. The gelation behaviors in response to temperature, pH changes, metal cations, and UV-vis light irradiation are investigated. Compounds 1 and 2 could selectively sense the Cu2+ cation in the presence of other metal cations. Moreover, compound 2 with a perfluoroalkyl group shows phase selective gelation ability. This work also provides a valuable reference for exploiting photosensitive materials as chemosensors.

[Prenatal diagnosis of a fetus in a family with mandibulofacial dysostosis].

OBJECTIVE: To measure the feasibility of application of comparative genomic hybridization technique in the prenatal diagnosis of fetus with mandibulofacial dysostosis. METHODS: A pregnant woman having a fetus with mandibulofacial dysostosis diagnosed by prenatal ultrasound test was selected. The amniotic fluid and blood of the pregnant and blood of her husband were collected and conventional cytogenetic analysis was performed. The whole genome was scanned by array comparative genomic hybridization assay (array-CGH). Reverse transcription fluorescence quantitative PCR (RT-qPCR) analysis was used to verify the result of array-CGH. RESULTS: No abnormality was found in conventional cytogenetic analysis while a duplicated region in 1p36.33 was detected by array-CGH assay. The region spans 722 kb and contains two genes, VWA1 and PYGO2, which play roles in the development of cartilage. The result of array-CGH was confirmed by the RT-qPCR assay. The diagnosis of mandibulofacial dysostosis was confirmed after birth. CONCLUSION: Author diagnosed a fetus with mandibulofacial dysostosis by array-CGH assay and found two candidate genes related to the development of craniofacial bone: VWA1 and PYGO2.

[Determination and identification of synthetic food colors based on fluorescence spectroscopy and radial basis function neural networks].

Taking ponceau 4R and amaranth as an example, concentration prediction and kind identification of synthetic food colors by fluorescence spectroscopy and radial basis function neural networks are introduced. By using SP-2558 multifunctional spectral measuring system, the fluorescence spectra were measured for solution of ponceau 4R and amaranth excited respectively by the light with the wavelength of 300 and 400 nm. For each sample solution of ponceau 4R, 15 emission wavelength values were selected. The fluorescence intensity corresponding to the selected wavelength was used as the network characteristic parameters, and a radial basis function neural network for concentration prediction was trained and constructed. It was employed to predict ponceau 4R solution concentration of the three kinds of samples, and the relative errors of prediction were 1.42%, 1.44% and 3.93% respectively. In addition, for solution of ponceau 4R and amaranth, the fluorescence intensity corresponding to the fluorescence wavelength was used as the network characteristic parameters, and a radial basis function neural network for kind identification was trained and constructed. It was employed to identify the kind of food colors, and the accuracy is 100%. These results show that the method is convenient, fast, and highly accurate, and can be used for the detection of synthetic food color in food safety supervision and management.

[Quantitative determination of melamine by fluorescence spectroscopy and radial basis function neural networks].

Based on the experimental study, it was found that melamine solution excited by UV light can generate a strong fluorescence. The fluorescence spectrum is within a range from 310 to 600 nm, the peak wavelength of the fluorescence is about 420 nm, and the relationship between fluorescence intensity and melamine solution concentration is nonlinear. A method for the determination of melamine solution concentration was presented, which was based on fluorescence spectroscopy and radial basis function neural networks. For each sample, 30 emission wavelength values were selected, the fluorescence intensity corresponding to the selected wavelength was used as the network data, and a radial basis function neural network was trained and constructed. The trained radial basis function neural network was employed to predict the melamine solution concentration in five kinds of samples, and the relative errors of the results were 0.93%, 0.09%, 0.31%, 1.55% and 4.61%, respectively. The results show that this method can determine the content of melamine quickly and accurately. The whole research outcomes will provide a new method for determining the content of melamine and food safety supervision.

Neuronal Activity in the Cerebellum During the Sleep-Wakefulness Transition in Mice.

Cerebellar malfunction can lead to sleep disturbance such as excessive daytime sleepiness, suggesting that the cerebellum may be involved in regulating sleep and/or wakefulness. However, understanding the features of cerebellar regulation in sleep and wakefulness states requires a detailed characterization of neuronal activity within this area. By performing multiple-unit recordings in mice, we showed that Purkinje cells (PCs) in the cerebellar cortex exhibited increased firing activity prior to the transition from sleep to wakefulness. Notably, the increased PC activity resulted from the inputs of low-frequency non-PC units in the cerebellar cortex. Moreover, the increased PC activity was accompanied by decreased activity in neurons of the deep cerebellar nuclei at the non-rapid eye-movement sleep-wakefulness transition. Our results provide in vivo electrophysiological evidence that the cerebellum has the potential to actively regulate the sleep-wakefulness transition.

[Fluorescence spectroscopy study of synthetic food colors].

According to the characteristic of synthetic food colors molecule and the relationship between fluorescence and molecular structure, and through analyzing, it has been concluded that synthetic food colors is fluorescent material. By using SP-2558 multifunctional spectral measuring system, the three-dimensional fluorescence spectra of ponceau 4R, amaranth, tartrazine, sunset yellow and brilliant blue were measured. The results show that ponceau 4R excited by light at the wavelength of 330-430 nm can generate a strong fluorescence at the 621 nm peak wavelength with its best excitation wavelength being 376 nm, amaranth excited by light at the wavelength of 300-440 nm can generate a strong fluorescence at the 643 nm peak wavelength with its best excitation wavelength being 370 nm, tartrazine excited by light at the wavelength of 280-380 nm can generate a strong fluorescence at the 565 nm peak wavelength with its best excitation wavelength being 315 nm, sunset yellow excited by light with wavelength of 310-410 nm can generate a strong fluorescence at the 592 nm peak wavelength with its best excitation wavelength being 348 nm, and brilliant blue excited by light at the wavelength of 320-390 nm can generate a strong fluorescence at the 456 nm peak wavelength with its best excitation wavelength being 350 nm. Moreover, the fluorescence spectra of the five kinds of synthetic food colors were discussed. These results can provide helps for testing of food colors and food safety.

Identification of a novel regeneration-related gene H3 and its protein from the differential expression cDNA library of spinal cord injury in neonatal rats.

OBJECTIVE: To clone and identify one novel regeneration related gene H(3) (CA854305) from the differential expression genes library we had set up before. METHODS: Use the method of Northern blot to detect the different expressions of the novel gene under different situations, employ the technique of in silico cloning to scan the span of the novel gene, and analyze their sequences. Also we used reverse transcription PCR to validate the largest open reading frame. RESULTS: Northern blotting results of H(3) (CA854305) showed that the transplanted group had more efficient and extensive expression than untreated and uninjured groups 5 days after spinal cord injury, while the untreated group had more extensive expression than uninjured group. It implied that H(3) might have some relationship with nerve regeneration after spinal cord injury. From the results of in silico cloning we got a longest contig of 1635 bp and an largest open reading frame of 542 bp from 49 to 591 bp correspondent with the Cozak rules. Reverse transcription PCR validated the largest open reading frame sequence primarily. CONCLUSIONS: We got the sequence of novel gene H(3) which might be one of the regenerationjrelated genes. Key words:Gene library; Genes; Nerve regeneration; Spinal cord injuries.

Motor neuron degeneration following glycine-mediated excitotoxicity induces spastic paralysis after spinal cord ischemia/reperfusion injury in rabbit.

Spinal cord ischemia and reperfusion (SCIR) injury is the major cause of a wide range of complications, including neural degeneration and devastating paraplegia. Decrease of inhibitory neurotransmitters and increase of excitory neurotransmitters are the major cause for the excitotoxicity of neurons. However, no study has reported the temporal loss of motor neuron in the ventral horn of spinal cord area following SCIR-induced spastic paralysis, not even the mechanism under it. In the present study, we found that the rabbits were mainly spastic paralyzed after spinal cord ischemia-reperfusion injury. And the ischemia 60 min group is the optimal treating condition, because of the higher rate of spastic paralysis and lower mortality. Motor neurons in the ventral horn of spinal cord were significant degeneration at 3 h following spastic paralysis and only 12.5% motor neurons were observed at 72 h post-operation, compared with control group. ELISA results indicated that Glycine and GABA were both downregulated following spastic paralysis. But Glycine immediately decreased at 10 min post-operation and lasted for the whole process (at least 72 h). Meanwhile GABA only significantly decreased at 72 h. Furthermore, Glutamic expression was significant upregulation at 3 hours post-operation, and the upregulation back to the base level at 72 h post-operation. Glutamic receptor-(NR1) and Glycine α1 receptor upregulated accordingly, whereas GABBR2 didn't upregulate significantly until at 72 h post-operation. Abundant extracellular Ca2+ influxed into cytoplasm in neurons following spastic paralysis. The type of paraplegia is mainly spastic paraplegia after SCIR (ischemia 60 min treatment). Following spastic paraplegia, motor neuron in the ventral horn of spinal cord area was significant degeneration at early stage and last for the whole process. It may contribute to the decrease of Glycine at early stage and followed exitotoxicity, which caused intracellular calcium overload to make neurons dead. It would lay the foundation for better understanding the motor neuron degeneration and mechanism following spastic paralysis. And it would supply a novel and effective target for spastic paralysis prevention and therapy.

Elimination of methane in exhaust gas from biogas upgrading process by immobilized methane-oxidizing bacteria.

Biogas upgrading is essential for the comprehensive utilization of biogas as substitute of natural gas. However, the methane in the biogas can be fully recovered during the upgrading process of biogas, and the exhaust gas produced during biogas upgrading may contain a very low concentration of methane. If the exhaust gas with low concentration methane releases to atmosphere, it will be harmful to environment. In addition, the utilization of large amounts of digestate produced from biogas plant is another important issue for the development of biogas industry. In this study, solid digestate was used to produce active carbon, which was subsequently used as immobilized material for methane-oxidizing bacteria (MOB) in biofilter. Biofilter with MOB immobilized on active carbon was used to eliminate the methane in exhaust gas from biogas upgrading process. Results showed porous active carbon was successfully made from solid digestate. The final methane elimination capacity of immobilized MOB reached about 0.13molh-1m-3, which was more 4 times higher than that of MOB without immobilization.

Local injection of Lenti-Olig2 at lesion site promotes functional recovery of spinal cord injury in rats.

AIMS: Olig2 is one of the most critical factors during CNS development, which belongs to b-HLH transcription factor family. Previous reports have shown that Olig2 regulates the remyelination processes in CNS demyelination diseases models. However, the role of Olig2 in contusion spinal cord injury (SCI) and the possible therapeutic effects remain obscure. This study aims to investigate the effects of overexpression Olig2 by lentivirus on adult spinal cord injury rats. METHODS: Lenti-Olig2 expression and control Lenti-eGFP vectors were prepared, and virus in a total of 5 µL (108 TU/mL) was locally injected into the injured spinal cord 1.5 mm rostral and caudal near the epicenter. Immunostaining, Western blot, electron microscopy, and CatWalk analyzes were employed to investigate the effects of Olig2 on spinal cord tissue repair and functional recovery. RESULTS: Injection of Lenti-Olig2 significantly increased the number of oligodendrocytes lineage cells and enhanced myelination after SCI. More importantly, the introduction of Olig2 greatly improved hindlimb locomotor performances. Other oligodendrocyte-related transcription factors, which were downregulated or upregulated after injury, were reversed by Olig2 induction. CONCLUSIONS: Our findings provided the evidence that overexpression Olig2 promotes myelination and locomotor recovery of contusion SCI, which gives us more understanding of Olig2 on spinal cord injury treatment.

Spontaneous discharges of pyramidal cells in the dorsal hippocampus of guinea pig.

To determine the characteristics of spontaneous discharges of hippocampal pyramidal cells (PCs), extracellular neuronal firing in CA1 and CA3 regions of dorsal hippocampus was recorded, the firing modes and interspike interval (ISI) were analyzed with the conventional and nonlinear methods. PCs were discriminated from interneurons using the measurement of action-potential duration and firing rate in this study. There was no significant difference in duration, mean firing frequency, complexity and firing mode between the neurons in CA1 and CA3 regions both in anesthetized and awake animals. The complexity of neurons was higher in awake group than that in anesthetized group, though no difference was found in firing rate. There were differences in the type of pyramidal cells and the coefficient of variance of ISI of neurons. The results obtained from the spontaneous discharges of dorsal hippocampal pyramidal cells reveal some nonlinear and linear aspects in anesthetized and awake states. It seems likely that the combination of conventional and non-linear measurements of the hippocampal pyramidal cells encoding may reflect genuine characteristics of the hippocampal pyramidal cells.

Wnt signaling pathway participates in valproic acid-induced neuronal differentiation of neural stem cells.

Neural stem cells (NSCs) are multipotent cells that have the capacity for differentiation into the major cell types of the nervous system, i.e. neurons, astrocytes and oligodendrocytes. Valproic acid (VPA) is a widely prescribed drug for seizures and bipolar disorder in clinic. Previously, a number of researches have been shown that VPA has differential effects on growth, proliferation and differentiation in many types of cells. However, whether VPA can induce NSCs from embryonic cerebral cortex differentiate into neurons and its possible molecular mechanism is also not clear. Wnt signaling is implicated in the control of cell growth and differentiation during CNS development in animal model, but its action at the cellular level has been poorly understood. In this experiment, we examined neuronal differentiation of NSCs induced by VPA culture media using vitro immunochemistry assay. The neuronal differentiation of NSCs was examined after treated with 0.75 mM VPA for three, seven and ten days. RT-PCR assay was employed to examine the level of Wnt-3α and ß-catenin. The results indicated that there were more ß-tublin III positive cells in NSCs treated with VPA medium compared to the control group. The expression of Wnt-3α and ß-catenin in NSCs treated with VPA medium was significantly greater compared to that of control media. In conclusion, these findings indicated that VPA could induce neuronal differentiation of NSCs by activating Wnt signal pathway.

Retinoic acid induced the differentiation of neural stem cells from embryonic spinal cord into functional neurons in vitro.

Retinoic acid is an important molecular taking part in the development and homeostasis of nervous system. Neural stem cells (NSCs) are pluripotent cells that can differentiate into three main neural cells including neuron, astrocyte and oligodendrocyte. However, whether retinoic acid can induce NSCs derived from embryonic spinal cord differentiating into functional neurons and its efficiency are not clear. In this experiment, NSCs were isolated from embryonic 14 d spinal cord of rats. The growth and neuronal differentiation of NSCs induced by 500 nM RA was examined in vitro. It was indicated that compared with the control group, there were more differentiated cells with longer cytodendrites in the medium treated with RA at different time. And more, there were more neuronal marker positive cells in 500 nM RA group than the control group seven days after differentiation. At the same time, the expression of ß-tublin III protein in RA group was higher than those in control group, which was contrary to the expression of astrocyte marker GFAP protein at seven days after differentiation. However the differentiated neurons, whether treated with RA or not both exhibited biological electrical reactivity after stimulated by glutamine. Therefore, these findings indicated that RA could promote growth of cellular dendrites and neuronal differentiation of NSCs, which also induce functional maturation of differentiated neurons finally.

Ameliorative Effects of p75NTR-ED-Fc on Axonal Regeneration and Functional Recovery in Spinal Cord-Injured Rats.

As a co-receptor of Nogo-66 receptor (NgR) and a critical receptor for paired immunoglobulin-like receptor (PirB), p75 neurotrophin receptor (p75NTR) mediates the inhibitory effects of myelin-associated inhibitors on axonal regeneration after spinal cord injury. Therefore, the p75NTR antagonist, such as recombinant p75NTR protein or its homogenates may block the inhibitory effects of myelin and promote the axonal regeneration and functional recovery. The purposes of this study are to subclone and express the extracellular domain gene of human p75NTR with IgG-Fc (hp75NTR-ED-Fc) in prokaryotic expression system and investigate the effects of the recombinant protein on axonal regeneration and functional recovery in spinal cord-injured rats. The hp75NTR-ED-Fc coding sequence was amplified from pcDNA-hp75NTR-ED-Fc by polymerase chain reaction (PCR) and subcloned into vector pET32a (+), then the effects of the purified recombinant protein on neurite outgrowth of dorsal root ganglion (DRG) neurons cultured with myelin-associated glycoprotein (MAG) were determined, and the effects of the fusion protein on axonal regeneration, functional recovery, and its possible mechanisms in spinal cord-injured rats were further investigated. The results indicated that the purified infusion protein could promote neurite outgrowth of DRG neurons, promote axonal regeneration and functional recovery, and decrease RhoA activation in spinal cord-injured rats. Taken together, the findings revealed that p75NTR still may be a potential and novel target for therapeutic intervention for spinal cord injury and that the hp75NTR-ED-Fc fusion protein treatment enhances functional recovery by limiting tissue loss and stimulating axonal growth in spinal cord-injured rats, which may result from decreasing the activation of RhoA.

Protective effects of adenoviral cardiotrophin-1 gene transfer on rubrospinal neurons after spinal cord injury in adult rats.

Cardiotrophin-1 (CT-1), a muscle-derived cytokine, supports the survival of motoneurons in vivo and in vitro. The present study investigated whether adenoviral huCT-1 gene transfer protected injured neurons from cell death or atrophy and promoted regeneration of rubrospinal tract (RST) after spinal cord injury in adult rats. Administration of the adenoviral CT-1 vector (Adv-CT1) to C3-4 lateral funiculus hemisection cavity, that completely interrupted RST, led to sustained CT-1 expression. Providing Adv-CT1, which rescued 20% of neurons, could prevent the loss of injured rubrospinal neurons 8 weeks post-injury. Retrograde tracing with FluoroGold showed that 1.2% of RST neurons regenerated at least two segments caudal to the injury site. Anterograde tracing with biotinylated dextran amine revealed that the RST axons terminated in white matter and gray matter. Behavioral testing revealed a significant functional recovery in limb usage. This observation indicated that adenoviral CT-1 gene transfer into the injured cord promoted survival and regeneration of rubrospinal neurons in adult rats.

Inhibiting PTEN protects hippocampal neurons against stretch injury by decreasing membrane translocation of AMPA receptor GluR2 subunit.

The AMPA type of glutamate receptors (AMPARs)-mediated excitotoxicity is involved in the secondary neuronal death following traumatic brain injury (TBI). But the underlying cellular and molecular mechanisms remain unclear. In this study, the role of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in GluR2-lacking AMPARs mediated neuronal death was investigated through an in vitro stretch injury model of neurons. It was indicated that both the mRNA and protein levels of PTEN were increased in cultured hippocampal neurons after stretch injury, which was associated with the decreasing expression of GluR2 subunits on the surface of neuronal membrane. Inhibition of PTEN activity by its inhibitor can promote the survival of neurons through preventing reduction of GluR2 on membrane. Moreover, the effect of inhibiting GluR2-lacking AMPARs was similar to PTEN suppression-mediated neuroprotective effect in stretch injury-induced neuronal death. Further evidence identified that the total GluR2 protein of neurons was not changed in all groups. So inhibition of PTEN or blockage of GluR2-lacking AMPARs may attenuate the death of hippocampal neurons post injury through decreasing the translocation of GluR2 subunit on the membrane effectively.

A novel COL7A1 gene mutation causing pretibial epidermolysis bullosa: report of a Chinese family with intra-familial phenotypical diversity.

Pretibial epidermolysis bullosa (PEB) is an extremely rare subtype of dominant dystrophic epidermolysis bullosa (DDEB) caused by mutation of the COL7A1 gene. More than 730 mutations have been identified in patients with DDEB, but only five mutations have been found to be related to PEB. In this study, a novel heterozygous nucleotide G>T transition at position 6101 in exon 73 of COL7A1 was detected, which resulted in a glycine to valine substitution (G2034V) in the triple-helical domain of type-VII collagen. This is the first report to show that one mutation caused a broad range of severity of disease in one family with PEB. These data suggest that c.6101G>T may influence the phenotype of PEB. They also contribute to the expanding database on COL7A1 mutations.