435 research outputs found
An extended Fourier pseudospectral method for the Gross-Pitaevskii equation with low regularity potential
We propose and analyze an extended Fourier pseudospectral (eFP) method for
the spatial discretization of the Gross-Pitaevskii equation (GPE) with low
regularity potential by treating the potential in an extended window for its
discrete Fourier transform. The proposed eFP method maintains optimal
convergence rates with respect to the regularity of the exact solution even if
the potential is of low regularity and enjoys similar computational cost as the
standard Fourier pseudospectral method, and thus it is both efficient and
accurate. Furthermore, similar to the Fourier spectral/pseudospectral methods,
the eFP method can be easily coupled with different popular temporal
integrators including finite difference methods, time-splitting methods and
exponential-type integrators. Numerical results are presented to validate our
optimal error estimates and to demonstrate that they are sharp as well as to
show its efficiency in practical computations.Comment: 20 pages, 7 figure
Geometric bionics: Lotus effect helps polystyrene nanotube films get good blood compatibility
Various biomaterials have been widely used for manufacturing biomedical applications including artificial organs, medical devices and disposable clinical apparatus, such as vascular prostheses, blood pumps, artificial kidney, artificial hearts, dialyzers and plasma separators, which could be used in contact with blood^1^. However, the research tasks of improving hemocompatibility of biomaterials have been carrying out with the development of biomedical requirements^2^. Since the interactions that lead to surface-induced thrombosis occurring at the blood-biomaterial interface become a reason of familiar current complications with grafts therapy, improvement of the blood compatibility of artificial polymer surfaces is, therefore a major issue in biomaterials science^3^. After decades of focused research, various approaches of modifying biomaterial surfaces through chemical or biochemical methods to improve their hemocompatibility were obtained^1^. In this article, we report that polystyrene nanotube films with morphology similar to the papilla on lotus leaf can be used as blood-contacted biomaterials by virtue of Lotus effect^4^. Clearly, this idea, resulting from geometric bionics that mimicking the structure design of lotus leaf, is very novel technique for preparation of hemocompatible biomaterials
UPF2-dependent nonsense-mediated mRNA decay pathway is essential for spermatogenesis by selectively eliminating longer 3'UTR transcripts
During transcription, most eukaryotic genes generate multiple alternative cleavage and polyadenylation (APA) sites, leading to the production of transcript isoforms with variable lengths in the 3' untranslated region (3'UTR). In contrast to somatic cells, male germ cells, especially pachytene spermatocytes and round spermatids, express a distinct reservoir of mRNAs with shorter 3'UTRs that are essential for spermatogenesis and male fertility. However, the mechanisms underlying the enrichment of shorter 3'UTR transcripts in the developing male germ cells remain unknown. Here, we report that UPF2-mediated nonsense-mediated mRNA decay (NMD) plays an essential role in male germ cells by eliminating ubiquitous genes-derived, longer 3'UTR transcripts, and that this role is independent of its canonical role in degrading "premature termination codon" (PTC)-containing transcripts in somatic cell lineages. This report provides physiological evidence supporting a noncanonical role of the NMD pathway in achieving global 3'UTR shortening in the male germ cells during spermatogenesis
Radiative transitions in charmonium from twisted mass lattice QCD
We present a study for charmonium radiative transitions:
, and
using twisted mass lattice QCD gauge
configurations. The single-quark vector form factors for and
are also determined. The simulation is performed at a lattice
spacing of fm and the lattice size is . After
extrapolation of lattice data at nonzero to 0, we compare our results
with previous quenched lattice results and the available experimental values.Comment: typeset with revtex, 15 pages, 11 figures, 4 table
Rottlerin Inhibits Lonicera japonica-Induced Photokilling in Human Lung Cancer Cells through Cytoskeleton-Related Signaling Cascade
This study demonstrated that many apoptotic signaling pathways, such as Rho family, PKC family, MAP kinase family, and mitochondria-mediated apoptotic pathway, were triggered by Lonicera japonica extracts and irradiation in CH27 cells. Rottlerin, a PKCδ
-selective inhibitor, reversed the photoactivated Lonicera japonica extract-induced decrease in PKCδ protein expression and change in cell morphology in this study. In addition, rottlerin inhibited the photoactivated Lonicera japonica-induced decrease in protein expression of Ras, ERK, p38, PKCα, and PKCε, which are the kinases of prosurvival signaling pathway. We also demonstrated that pretreatment with rottlerin prevented actin microfilaments and microtubules from damage during the photoactivated Lonicera japonica-induced CH27 cell death. Furthermore, the promotion of the cytoskeleton-related signaling cascade following rottlerin by upregulation of cytoskeleton-related mediators (p38, HSP27, FAK, paxillin, and tubulin) and molecules of downstream of F-actin (mitochondria-mediated apoptosis pathway) reduces CH27 cell death, indicating that cytoskeleton is the potential target in the photoactivated Lonicera japonicaextract-induced photokilling of CH27 cells
Investigation of the morbidity of dry eye among special crowd in Shunde district
AIM: To investigate the morbidity of dry eye in policeman of Shunde district, and to analyze the related factors and proposed methods of preventing and treating dry eye.<p>METHODS:Totally 650 policemen who came for physical examination in Shunde district recived questionnaire survey. The patients with dye eye disease were finally diagnosed through slit lamp examination, Schirmer test, tear film break-up time(BUT)measurement and keratoconjunctival fluorescent staining. The morbidity among different policemen was further analyzed and stasticed.<p>RESULTS:The results showed that 152 in 650 policemen suffered from dry eye disease, the ratio was 23.4%. Comparied with security police and crimanl police, the ratio in traffic police, patrolman,and back office police was significantly higher. The prevalence was higher when the ages were greater than 40.<p>CONCLUSION: Unsuitable working environment, air contamination are high risk factors of dry eye disease
Improving Hypoxia Adaption Causes Distinct Effects on Growth and Bioactive Compounds Synthesis in an Entomopathogenic Fungus Cordyceps militaris
Cordyceps militaris is an entomopathogenic fungus producing a variety of bioactive compounds. To meet the huge demand for medicinal and edible products, industrialized fermentation of mycelia and cultivation of stromata have been widely developed in China. The content of bioactive metabolites of C. militaris, such as cordycepin, is higher when cultivated on silkworm pupae than on rice or in broth. However, compared with other cultivation methods, C. militaris grows more slowly and accumulates less biomass. The hypoxic environment in pupa hemocoel is one of environmental factor which is not existed in other cultivation methods. It is suggested that hypoxia plays an important role on the growth and the synthesis of bioactive compounds in C. militaris. Here, we demonstrated that the distinct effects on the growth and synthesis of bioactive compounds employing different strategies of improving hypoxia adaption. The introduction of Vitreoscilla hemoglobin enhanced growth, biomass accumulation, and crude polysaccharides content of C. militaris. However, cordycepin production was decreased to 9–15% of the control group. Meanwhile, the yield of adenosine was increased significantly. Nonetheless, when the predicted bHLH transcription factor of sterol regulatory element binding proteins (SREBPs) was overexpressed in C. militaris to improve the hypoxia adaption of fungal cells, cordycepin content was significantly increased more than two-fold. These findings reveal the role of SREBPs on growth and bioactive compounds synthesis. And it also provides a scientific basis for rationally engineering strains and optimization strategies of air supply in cultivation and fermentation
Bisdemethoxycurcumin Increases Sirt1 to Antagonize t
Curcuminoids are well known for their capabilities to combat risk factors that are associated with ageing and cellular senescence. Recent reports have demonstrated that curcuminoids can extend the lifespan of model organisms. However, the underlying mechanisms by which these polyphenic compounds exert these beneficial effects remain unknown. In this study, t-BHP-induced premature senescence model in human fibroblasts was chosen to explore the protective effects of a curcuminoid, bisdemethoxycurcumin (BDMC), on cellular senescence. The results demonstrated that BDMC attenuated oxidative stress-induced senescence-like features which include the induction of an enlarged cellular appearance, higher frequency of senescence-associated β-galactosidase staining activity, appearance of senescence-associated heterochromatic foci in nuclei, decrease in proliferation capability, and alteration in related molecules such as p16 and retinoblastoma protein. Notably, we found that BDMC treatment activated Sirt1/AMPK signaling pathway. Moreover, downregulating Sirt1 by the pharmacological inhibitor nicotianamine or small interfering RNA blocked BDMC-mediated protection against t-BHP-mediated decrease in proliferation. These results suggested that BDMC prevented t-BHP-induced cellular senescence, and BDMC-induced Sirt1 may be a mechanism mediating its beneficial effects
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