2,095 research outputs found
DLC2 modulates angiogenic responses in vascular endothelial cells by regulating cell attachment and migration.
Deleted in liver cancer 1 (DLC1) is a RhoGTPase activation protein-containing tumor suppressor that associates with various types of cancer. Although DLC2 shares a similar domain structure with that of DLC1, the function of DLC2 is not well characterized. Here, we describe the expression and ablation of DLC2 in mice using a reporter-knockout approach. DLC2 is expressed in several tissues and in endothelial cells (ECs) of blood vessels. Although ECs and blood vessels show no histological abnormalities and mice appear overall healthy, DLC2-mutant mice display enhanced angiogenic responses induced by matrigel and by tumor cells. Silencing of DLC2 in human ECs has reduced cell attachment, increased migration, and tube formation. These changes are rescued by silencing of RhoA, suggesting that the process is RhoA pathway dependent. These results indicate that DLC2 is not required for mouse development and normal vessel formation, but may protect mouse from unwanted angiogenesis induced by, for example, tumor cells
Instantaneous 4D micro-particle image velocimetry (mu PIV) via multifocal microscopy (MUM)
Multifocal microscopy (MUM), a technique to capture multiple fields of view (FOVs) from distinct axial planes simultaneously and on one camera, was used to perform micro-particle image velocimetry (Β΅PIV) to reconstruct velocity and shear stress fields imposed by a liquid flowing around a cell. A diffraction based multifocal relay was used to capture images from three different planes with 630 nm axial spacing from which the axial positions of the flow-tracing particles were calculated using the image sharpness metric. It was shown that MUM can achieve an accuracy on the calculated velocity of around (0.52βΒ±β0.19) Β΅m/s. Using fixed cells, MUM imaged the flow perturbations at sub-cellular level, which showed characteristics similar to those observed in the literature. Using live cells as an exemplar, MUM observed the effect of changing cell morphology on the local flow during perfusion. Compared to standard confocal laser scanning microscope, MUM offers a clear advantage in acquisition speed for Β΅PIV (over 300 times faster). This is an important characteristic for rapidly evolving biological systems where there is the necessity to monitor in real time entire volumes to correlate the sample responses to the external forces
Demonstration of a self-pulsing photonic crystal Fano laser
Semiconductor lasers in use today rely on mirrors based on the reflection at
a cleaved facet or Bragg reflection from a periodic stack of layers. Here, we
demonstrate an ultra-small laser with a mirror based on the Fano resonance
between a continuum of waveguide modes and the discrete resonance of a
nanocavity. The Fano resonance leads to unique laser characteristics. Since the
Fano mirror is very narrow-band compared to conventional lasers, the laser is
single-mode and in particular, it can be modulated via the mirror. We show,
experimentally and theoretically, that nonlinearities in the mirror may even
promote the generation of a self-sustained train of pulses at gigahertz
frequencies, an effect that was previously only observed in macroscopic lasers.
Such a source is of interest for a number of applications within integrated
photonics
Interleukin-1Ξ² sequesters hypoxia inducible factor 2Ξ± to the primary cilium.
BACKGROUND: The primary cilium coordinates signalling in development, health and disease. Previously we have shown that the cilium is essential for the anabolic response to loading and the inflammatory response to interleukin-1Ξ² (IL-1Ξ²). We have also shown the primary cilium elongates in response to IL-1Ξ² exposure. Both anabolic phenotype and inflammatory pathology are proposed to be dependent on hypoxia-inducible factor 2 alpha (HIF-2Ξ±). The present study tests the hypothesis that an association exists between the primary cilium and HIFs in inflammatory signalling. RESULTS: Here we show, in articular chondrocytes, that IL-1Ξ²-induces primary cilia elongation with alterations to cilia trafficking of arl13b. This elongation is associated with a transient increase in HIF-2Ξ± expression and accumulation in the primary cilium. Prolyl hydroxylase inhibition results in primary cilia elongation also associated with accumulation of HIF-2Ξ± in the ciliary base and axoneme. This recruitment and the associated cilia elongation is not inhibited by blockade of HIFΞ± transcription activity or rescue of basal HIF-2Ξ± expression. Hypomorphic mutation to intraflagellar transport protein IFT88 results in limited ciliogenesis. This is associated with increased HIF-2Ξ± expression and inhibited response to prolyl hydroxylase inhibition. CONCLUSIONS: These findings suggest that ciliary sequestration of HIF-2Ξ± provides negative regulation of HIF-2Ξ± expression and potentially activity. This study indicates, for the first time, that the primary cilium regulates HIF signalling during inflammation
Application of functionalized nanofluid in thermosyphon
A water-based functionalized nanofluid was made by surface functionalizing the ordinary silica nanoparticles. The functionalized nanofluid can keep long-term stability. and no sedimentation was observed. The functionalized nanofluid as the working fluid is applied in a thermosyphon to understand the effect of this special nanofluid on the thermal performance of the thermosyphon. The experiment was carried out under steady operating pressures. The same work was also explored for traditional nanofluid (consisting of water and the same silica nanoparticles without functionalization) for comparison. Results indicate that a porous deposition layer exists on the heated surface of the evaporator during the operating process using traditional nanofluid; however, no coating layer exists for functionalized nanofluid. Functionalized nanofluid can enhance the evaporating heat transfer coefficient, while it has generally no effect on the maximum heat flux. Traditional nanofluid deteriorates the evaporating heat transfer coefficient but enhances the maximum heat flux. The existence of the deposition layer affects mainly the thermal performance, and no meaningful nanofluid effect is found in the present study
Multiple-mode excitation in spin-transfer nanocontacts with dynamic polarizer
Author name used in this publication: A. RuotoloAuthor name used in this publication: Kwok, D. T. K.2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.
BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721
Identification of serum biomarkers of hepatocarcinoma through liquid chromatography/mass spectrometry-based metabonomic method
Late diagnosis of hepatocarcinoma (HCC) is one of the most primary factors for the poor survival of patients. Thereby, identification of sensitive and specific biomarkers for HCC early diagnosis is of great importance in biological medicine to date. In the present study, serum metabolites of the HCC patients and healthy controls were investigated using the improved liquid chromatographyβmass spectrometry (LC/MS). A wavelet-based method was utilized to find and align peaks of LCβMS. The characteristic peaks were selected by performing a two-sample t test statistics (p value <0.05). Clustering analysis based on principal component analysis showed a clear separation between HCC patients and healthy individuals. The serum metabolite, namely 1-methyladenosine, was identified as the characteristic metabolite for HCC. Moreover, receiverβoperator curves were calculated with 1-methyladenosine and/or alpha fetal protein (AFP). The higher area under curve value was achieved in 1-methyladenosine group than AFP group (0.802 vs. 0.592), and the diagnostic model combining 1-methyladenosine with AFP exhibited significant improved sensitivity, which could identify those patients who missed the diagnosis of HCC by determining serum AFP alone. Overall, these results suggested that LC/MS-based metabonomic study is a potent and promising strategy for identifying novel biomarkers of HCC
Endomorphism algebras of Abelian varieties with special reference to superelliptic Jacobians
This is (mostly) a survey article. We use an information about Galois properties of points of small order on an Abelian variety in order to describe its endomorphism algebra over an algebraic closure of the ground field. We discuss in detail applications to jacobians of cyclic covers of the projective line
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Experimental Studies on Bond Performance of BFRP bars reinforced Coral Aggregate Concrete
As part of this study, has been developed a numerical method which allows to establish abacuses connecting the normal force with bending moment for a circular section and therefore to predict the rupture of this type of section. This may be for reinforced concrete (traditional steel) or concrete reinforced with steel fibers. The numerical simulation was performed in nonlinear elasticity up to exhaustion of the bearing capacity of the section. The rupture modes considered occur by plasticization of the steel or rupture of the concrete (under compressive stresses or tensile stresses). Regarding the fiber-reinforced concrete, the rupture occurs, usually, by tearing of the fibers. The behavior laws of the different materials (concrete and steel) correspond to the real behavior. The influence of several parameters was investigated, namely; diameter of the section, concrete strength, type of steel, percentage of reinforcement and contribution of concrete in tension between two successive cracks of bending. A comparison was made with the behavior of a section considering the conventional diagrams of materials; provided by the BAEL rules. A second comparative study was performed for fibers reinforced section
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