720 research outputs found
GVD effect and nonlinear pulse propagation in 40Gbit/s optical fiber communication systems
AbstractIn this paper, group velocity dispersion (GVD) and second-order GVD effects are shortly discussed and then the limitations on the bit rate induced by dispersion or second-order GVD are estimated. For relative higher pulse energy and shorter pulse width in 40Gbit/s systems, self-phase modulation(SPM) is significant. The combined effect of GVD and SPM on the propagation pulses are analyzed through Nonlinear Schrödinger Equation(NLSE)
Transcriptional Regulations on the Low-Temperature-Induced Floral Transition in an Orchidaceae Species, Dendrobium nobile: An Expressed Sequence Tags Analysis
Vernalization-induced flowering is a cold-relevant adaptation in many species, but little is known about the genetic basis behind in Orchidaceae species. Here, we reported a collection of 15017 expressed sequence tags (ESTs) from the vernalized axillary buds of an Orchidaceae species, Dendrobium nobile, which were assembled for 9616 unique gene clusters. Functional enrichment analysis showed that genes in relation to the responses to stresses, especially in the form of low temperatures, and those involving in protein biosynthesis and chromatin assembly were significantly overrepresented during 40 days of vernalization. Additionally, a total of 59 putative flowering-relevant genes were recognized, including those homologous to known key players in vernalization pathways in temperate cereals or Arabidopsis, such as cereal VRN1, FT/VRN3, and Arabidopsis AGL19. Results from this study suggest that the networks regulating vernalization-induced floral transition are conserved, but just in a part, in D. nobile, temperate cereals, and Arabidopsis
Application of Principal Component Analysis Method to Determine Prediction Indexes Sensibility Sequence
AbstractScreening out sensitivity prediction indexes fit for the coal mine is very important technical work in coal and gas outburst prediction process. The feasibility that principal component analysis method been used in the coal and gas outburst prediction index screening is discussed. Through using gray correlation analysis method and principal component analysis method to analysis a batch of measured data of a coal mine, the validity of the latter is proved. Through the contrast of process between the gray correlation analysis and the principal component analysis method, the vantage of principal component analysis method is obvious, that is the better maneuverability, simplicity and easier to extend
Optimization of spray drying process of camellia oleifera seed oil microcapsule by response surface methodology
On the basis of single factor experiment,the processing technology of microencapsulated camellia oleifera seed oil was optimized by response surface method.The results showed that the optimized parameters were as follows: solid content 19%,inlet air temperature 180 ℃,and feed flow rate 16 mL/min.The order of the effects of various factors on the embedding rate of microencapsulated camellia oleifera seed oil was:solid content>feed flow rate>inlet air temperature
Nuclear factor κB controls acetylcholine receptor clustering at the neuromuscular junction
At the vertebrate neuromuscular junction (NMJ), acetylcholine receptor (AChR) clustering is stimulated by motor neuron-derived glycoprotein Agrin and requires a number of intracellular signal or structural proteins, including AChR-associated scaffold protein Rapsyn. Here, we report a role of nuclear factor κB (NF-κB), a well known transcription factor involved in a variety of immune responses, in regulating AChR clustering at the NMJ. We found that downregulating the expression of RelA/p65 subunit of NF-κB or inhibiting NF-κB activity by overexpression of mutated form of IκB (inhibitor κB), which is resistant to proteolytic degradation and thus constitutively keeps NF-κB inactive in the cytoplasma, impeded the formation of AChR clusters in cultured C2C12 muscle cells stimulated by Agrin. In contrast, overexpression of RelA/p65 promoted AChR clustering. Furthermore, we investigated the mechanism by which NF-κB regulates AChR clustering. Interestingly, we found that downregulating the expression of RelA/p65 caused a marked reduction in the protein and mRNA level of Rapsyn and upregulation of RelA/p65 enhanced Rapsyn promoter activity. Mutation of NF-κB binding site on Rapsyn promoter prevented responsiveness to RelA/p65 regulation. Moreover, forced expression of Rapsyn in RelA/p65 downregulated muscle cells partially rescued AChR clusters, suggesting that NF-κB regulates AChR clustering, at least partially through the transcriptional regulation of Rapsyn. In line with this notion, genetic ablation of RelA/p65 selectively in the skeletal muscle caused a reduction of AChR density at the NMJ and a decrease in the level of Rapsyn. Thus, NF-κB signaling controls AChR clustering through transcriptional regulation of synaptic protein Rapsyn. Copyrigh
Retinal pigment epithelial cells secrete neurotrophic factors and synthesize dopamine: possible contribution to therapeutic effects of RPE cell transplantation in Parkinson's disease
<p>Abstract</p> <p>Background</p> <p>New strategies for the treatment of Parkinson's disease (PD) are shifted from dopamine (DA) replacement to regeneration or restoration of the nigro-striatal system. A cell therapy using human retinal pigment epithelial (RPE) cells as substitution for degenerated dopaminergic (DAergic) neurons has been developed and showed promising prospect in clinical treatment of PD, but the exact mechanism underlying this therapy is not fully elucidated. In the present study, we investigated whether the beneficial effects of this therapy are related to the trophic properties of RPE cells and their ability to synthesize DA.</p> <p>Methods</p> <p>We evaluated the protective effects of conditioned medium (CM) from cultured RPE cells on the DAergic cells against 6-hydroxydopamine (6-OHDA)- and rotenone-induced neurotoxicity and determined the levels of glial cell derived neurotrophic factor (GDNF) and brain derived neurotrophic factor (BDNF) released by RPE cells. We also measured the DA synthesis and release. Finally we transplanted microcarriers-RPE cells into 6-OHDA lesioned rats and observed the improvement in apomorphine-induced rotations (AIR).</p> <p>Results</p> <p>We report here: (1) CM from RPE cells can secret trophic factors GDNF and BDNF, and protect DAergic neurons against the 6-OHDA- and rotenone-induced cell injury; (2) cultured RPE cells express L-dopa decarboxylase (DDC) and synthesize DA; (3) RPE cells attached to microcarriers can survive in the host striatum and improve the AIR in 6-OHDA-lesioned animal model of PD; (4) GDNF and BDNF levels are found significantly higher in the RPE cell-grafted tissues.</p> <p>Conclusion</p> <p>These findings indicate the RPE cells have the ability to secret GDNF and BDNF, and synthesize DA, which probably contribute to the therapeutic effects of RPE cell transplantation in PD.</p
Correlations in Horizontal Branch Oscillations and Break Components in XTE J1701-462 and GX 17+2
We studied the horizontal branch oscillations (HBO) and the band-limited
components observed in the power spectra of the transient neutron star low-mass
X-ray binary XTE J1701-462 and the persistent "Sco-like" Z source GX 17+2.
These two components were studied based on the state-resolved spectra. We found
that the frequencies of XTE J1701-462 lie on the known correlations (WK and
PBK), showing consistency with other types of X-ray binaries (black holes,
atoll sources and millisecond X-ray pulsars). However, GX 17+2 is shifted from
the WK correlation like other typical Z sources. We suggest that the WK/PBK
main track forms a boundary which separates persistent sources from transient
sources. The characteristic frequencies of break and HBO are independent of
accretion rate in both sources, although it depends on spectral models. We also
report the energy dependence of the HBO and break frequencies in XTE J1701-462
and how the temporal properties change with spectral state in XTE J1701-462 and
GX 17+2. We studied the correlation between rms at the break and the HBO
frequency. We suggest that HBO and break components for both sources probably
arise from a similar physical mechanism: Comptonization emission from the
corona. These two components could be caused by same kind of oscillation in a
corona who with uneven density, and they could be generated from different
areas of corona. We further suggest that different proportions of the
Comptonization component in the total flux cause the different distribution
between GX 17+2 and XTE J1701-462 in the -
diagram.Comment: 36 pages, 7 figures, accpeted by Ap
Determination of DQ-798 in rat plasma by UHPLC-MS/MS and its application to a pharmacokinetic study
Fascin-1 and Digestive System Carcinoma
Invasion and metastasis are major reason for poor prognosis of digestive system carcinoma patients. Motility and migratory capacity are important in contributing to tumor cells’ invasion and metastasis. Fascin is one of actin cross-linking proteins and can participate in forming parallel actin bundles in cell protrusions. Fascin-1 is consequently involved in cell adhesion, motility, and signaling. In cultured cells, over-expression of fascin-1 can increase migration and invasion capacity of cells. Many studies show up-expressions of fascin-1 are significantly associated with worse prognosis, poor differentiation, TNM stage, positive for lymph node metastasis, and positive for distant metastasis in digestive system carcinoma patients. So fascin-1 may have prognostic value as an early biomarker for more aggressive digestive system carcinoma. This review provides detailed account of preclinical studies conducted to determine the utility of fascin-1 as a therapeutic and predictive agent in invasion and metastasis of carcinomas
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