A new design method for industrial portal frames in fire

For single-storey steel portal frames in fire, especially when they are situated close to a site perimeter, it is imperative that the boundary walls stay close to vertical, so that fires which occur are not allowed to spread to adjacent properties. A current UK fire design guide requires either that the whole frame be protected as a single element, or that the rafter may be left unprotected if column bases and foundations are designed to resist the forces and moments generated by rafter collapse, in order to ensure the lateral stability of the boundary walls. This can lead to very uneconomical foundation design and base-plate detailing. In previous studies carried out at the University of Sheffield it was found that a fundamental aspect of the collapse of a portal frame rafter is that it usually loses stability in a “snap-through” mechanism, but is capable of re-stabilising at high deflections, when the roof has inverted but the columns remain close to vertical. Numerical tests performed using the new model show that the strong base connections recommended by the current design method do not always lead to a conservative design. It is also found that initial collapse of the rafter is always caused by a plastic hinge mechanism based on the frame’s initial configuration. If the frame can then re-stabilize when the roof is substantially inverted, a second mechanism relying on the re-stabilized configuration can lead to failure of the whole frame. In this paper, a portal frame with different bases is simulated numerically using Vulcan, investigating the effect of different base strength on the collapse behaviour. The test results are compared with the failure mode assumed by the current design method. A new method for the estimation of re-stabilized positions of single-span frames in fire, using the second failure mechanism, is discussed and calibrated against the numerical test results

The comparison of immunomodulatory effects of peripheral mononuclear cells against proliferation in U937 in junior elderly habitual morning swimming in Taiwan cohort

The present investigation was carried out to evaluate the effect of greater immunomodulatory effects of human peripheral blood mononuclear cells against proliferation in human leukemia cells. To achieve this, cells U937 in junior elderly (with cool environmental physical activities) subjects with habitual morning swimming and sedentary lifestyle were recruited in relatively cool season in Taiwan; the isolated human peripheral blood mononuclear cells were stimulated by phytohemagglutinin to obtain the conditioned medium which contains various cytokines. However, the differential effects of the conditioned medium on growth inhibition in U937 leukemia cells were observed. The cytokines, including interferon-gamma, tumor necrosis factors-alpha and interleukine-2 secreted into conditioned medium were higher in the morning-swimming subjects than in the sedentary-lifestyle ones. Similarly, serum white blood cell, creatine phosphokinase, immunoglobulin G and immunoglobulin A in the morning-swimming and sedentary-lifestyle groups indicated that no further inflammatory status existed in the morning-swimming group. In summary, greater immunomodulatory effects of human peripheral blood mononuclear cells against proliferation in human leukemia cells U937 in junior elderly subjects came from the effects of regular moderate exercise in cool temperature rather than of inflammatory effects.Keywords: Immunomodulatory, junior elderly, morning swimming, leukemia, U937, human peripheral blood mononuclear cell

Highly reproducible SERS substrate based on polarization-free Ag nanoparticles decorated SiO2/Si core-shell nanowires array

SiO2/Si core-shell nanowires array coated with gap-rich silver nanoparticles were demonstrated as a highly reproducible surface-enhanced Raman scattering (SERS) substrate. SERS detection of a relative standard deviation of 8% for 10−4 M R6G with a spot size of ∼2 μm and 900 spots over an area of 150 × 150 μm2 was reported. The high reproducibility is ascribed to the polarization-independent electrical field distribution among three-dimensional nanowire structure with an optimized thickness of SiO2 shell layer.published_or_final_versio

PIKfyve, a class III lipid kinase, is required for TLR-induced type I IFN production via modulation of ATF3

Type I IFN plays a key role in antiviral responses. It also has been shown that deregulation of type I IFN expression following abnormal activation of TLRs contributes to the pathogenesis of systemic lupus erythematosus. In this study, we find that PIKfyve, a class III lipid kinase, is required for endolysosomal TLR-induced expression of type I IFN in mouse and human cells. PIKfyve binds to phosphatidylinositol 3-phosphate and synthesizes phosphatidylinositol 3,5-bisphosphate, and plays a critical role in endolysosomal trafficking. However, PIKfyve modulates type I IFN production via mechanisms independent of receptor and ligand trafficking in endolysosomes. Instead, pharmacological or genetic inactivation of PIKfyve rapidly induces expression of the transcription repressor ATF3, which is necessary and sufficient for suppression of type I IFN expression by bin'ding to its promoter and blocking its transcription. Thus, we have uncovered a novel phosphoinositide-mediated regulatory mechanism that controls TLR-mediated induction of type I IFN, which may provide a new therapeutic indication for the PIKfyve inhibitor.X111313Ysciescopu

Rapid detection of adulterated drugs in herbal dietary supplements by wooden-tip electrospray ionization mass spectrometry

Version of RecordPublishe

Microfluidic on-chip biomimicry for 3D cell culture: a fit-for-purpose investigation from the end user standpoint

A plethora of 3D and microfluidics-based culture models have been demonstrated in the recent years with the ultimate aim to facilitate predictive in vitro models for pharmaceutical development. This article summarizes to date the progress in the microfluidics-based tissue culture models, including organ-on-a-chip and vasculature-on-a-chip. Specific focus is placed on addressing the question of what kinds of 3D culture and system complexities are deemed desirable by the biological and biomedical community. This question is addressed through analysis of a research survey to evaluate the potential use of microfluidic cell culture models among the end users. Our results showed a willingness to adopt 3D culture technology among biomedical researchers, although a significant gap still exists between the desired systems and existing 3D culture options. With these results, key challenges and future directions are highlighted.This work has been supported by The Engineering and Physical Sciences Research Council (EPSRC) UK under the grant number EP/M018989/1, and a Royal Society Research Grant. Y Liu received a studentship from the Schlumberger Foundation, and E Gill received a scholarship from the WD Armstrong Trust

Review and comparison of shearography and active thermography for nondestructive evaluation

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The Classical Harmonic Vibrations of the Atomic Centers of Mass with Micro Amplitudes and Low Frequencies Monitored by the Entanglement between the Two Two-level Atoms in a Single mode Cavity

We study the entanglement dynamics of the two two-level atoms coupling with a single-mode polarized cavity field after incorporating the atomic centers of mass classical harmonic vibrations with micro amplitudes and low frequencies. We propose a quantitative vibrant factor to modify the concurrence of the two atoms states. When the vibrant frequencies are very low, we obtain that: (i) the factor depends on the relative vibrant displacements and the initial phases rather than the absolute amplitudes, and reduces the concurrence to three orders of magnitude; (ii) the concurrence increases with the increase of the initial phases; (iii) the frequency of the harmonic vibration can be obtained by measuring the maximal value of the concurrence during a small time. These results indicate that even the extremely weak classical harmonic vibrations can be monitored by the entanglement of quantum states.Comment: 10 pages, 3 figure

Effect of annealing on the performance of CrO3/ZnO light emitting diodes

Heterojunction CrO3/ZnO light emitting diodes have been fabricated. Their performance was investigated for different annealing temperature for ZnO nanorods. Annealing in oxygen atmosphere had significant influence on carrier concentration in the nanorods, as well as on the emission spectra of the nanorods. Surprisingly, annealing conditions, which yield the lowest band edge-to-defect emission ratio in the photoluminescence spectra, result in the highest band edge-to-defect emission ratio in the electroluminescence spectra. The influence of the native defects on ZnO light emitting diode performance is discussed. © 2009 American Institute of Physics.published_or_final_versio