Tunable CW diode-pumped Tm,Ho:YLiF4 laser operating at or near room temperature

A conversion efficiency of 42% and slope efficiency of 60% relative to absorbed pump power are obtained from a continuous wave diode-pumped Tm,Ho:YLiF4 laser at 2 microns with output power of 84 mW at a crystal temperature of 275 K. The emission spectrum is etalon tunable over a range of7 nm (16.3/cm) centered on 2.067 microns with fine tuning capability of the transition frequency with crystal temperature at a measured rate of -0.03/(cm)K. The effective emission cross-section is measured to be 5 x 10(exp -21) cm squared. These and other aspects of the laser performance are disclosed in the context of calculated atmospheric absorption characteristics in this spectral region and potential use in remote sensing applications. Single frequency output and frequency stabilization are achieved using an intracavity etalon in conjunction with an external reference etalon

Tunable CW diode-pumped Tm,Ho:YLiF4 laser operating at or near room temperature

A conversion efficiency of 42 percent and slope efficiency of 60 percent relative to absorbed pump power are obtained from a continuous wave diode-pumped Tm,Ho:YLiF4 laser at 2 microns with output power of 84mW at a crystal temperature of 275K. The emission spectrum is etalon tunable over a range of 7nm (16.3 cm(sup -1) centered on 2.067 microns with fine tuning capability of the transition frequency with crystal temperature at a measured rate of -0.03/(cm)K. The effective emission cross-section is measured to be 5 x 10(sup -21) cm squared. These and other aspects of the laser performance are disclosed in the context of calculated atmospheric absorption characteristics in this spectral region and potential use in remote sensing applications. Single frequency output and frequency stabilization are achieved using an intracavity etalon in conjunction with an external reference etalon

Goal-setting intervention to reduce occupational sedentary behaviour

Introduction: Occupational sedentary behaviour is an emerging public health concern. Office-based workplaces provide an ideal setting to implement an intervention due to the large proportion of sitting time reported during work hours. Previous sedentary behaviour interventions have included goal-setting as a behaviour change strategy with promising results. The aim of the current study was to explore the most and least effective goals as perceived by office-based workers for reducing occupational sedentary behaviour. Methods: Twenty-Seven University-based office workers participated in the study. Participants were invited to participate in an interview after the completion of a 6-week intervention where participants self-determined six incremental goals. The interview was audio recorded and transcribed verbatim. Following this, the data was thematically analysed. Results: As a collective group, the goals which were considered to be the most effective included walking further or up/down stairs to attend amenities, standing when the phone rang and/or standing for the duration of the phone call, walking further to fill water bottle, walking during a break or walking to visit colleagues or to a specific area. Coincidentally, the least effective goals included standing while on the phone and walking during the day. Conclusions: The findings suggest that the same goal can be considered to be the most or least effective for an individual. This indicated that sedentary behaviour goal-setting interventions need to account for individual preference and match the level of willingness of the participant as a 'one size fits all' approach is unlikely to be effective

Reliability and validity of the ActivPAL activity monitor for office-based tasks

The ActivPAL physical activity monitor has been previously reported as a reliable and valid tool to measure everyday physical activities. The aim of this study was to examine the reliability and validity of the ActivPAL during typical office-based activities. A convenient sample of 10 adults participated in this study with two ActivPAL units attached to the participant's right thigh. Participants completed 6 minutes of specific office-based tasks such as typing an email, writing on a whiteboard, collecting printing and running a small errand with instructions provided through an audio recording. Each bout was filmed with time of sitting, standing and walking visually assessed using the same categories provided by the ActivPAL analysis. Reliability between ActivPAL recordings was assessed via Wilcoxon comparisons and intraclass correlation coefficients (ICC). Relative error was calculated as the difference between visual observations and ActivPAL recordings. Validity was assessed via Wilcoxon comparisons between ActivPAL recordings and video observations. There were no significant differences between ActivPAL units for sitting (196.2+/-5.0 vs. 195.9+/-5.1 seconds), standing (121.8+/-4.8 vs. 122.3+/-6.9 seconds) or walking (42.0+/-6.1 vs. 41.9+/-7.1 seconds) activities. Significant ICC were detected for sitting (0.928), standing (0.849) and walking (0.849) time. In contrast, the ActivPAL recordings for sitting, standing and walking time were significantly different to visual observations (p3.8%, >24.5% and >54.1%, respectively. The current study has identified ActivPAL units as reliable tools to document physical activity. However, the ActivPAL underestimated sitting and walking time, and overestimated standing time during office-based tasks

Tunable hot-electron transfer within a single core-shell nanowire

We report the hot photoexcited electron transfer across the coaxial interface of a cylindrical core-shell nanowire. Modulation of the transfer rates, manifested as a large tunability of the voltage onset of negative differential resistance and of voltage-current phase, is achieved using three different modes. The coupling of electrostatic gating, incident photon energy, and the incident photon intensity to transfer rates is facilitated by the combined influences of geometric confinement and heterojunction shape on hot-electron transfer, and by electron-electron scattering rates that can be altered by varying the incident photon flux, with evidence of weak electron-phonon scattering. Dynamic manipulation of this transfer rate permits the introduction and control of a continuously adjustable phase delay of up to about 130° within a single nanometer-scale device element

Influence of pristine graphene particle sizes on physicochemical, microstructural and mechanical properties of Portland cement mortars

This paper aims to study the effect of the size of pristine graphene (PRG) particles on the compressive and tensile strengths of cement-based mortars and to gain better understandings of the mechanism behind the enhancement of these properties. PRG industrially manufactured by the electrochemical process with a variety of particle sizes including 5 µm, 43 µm, 56 µm, and 73 µm was used at the optimal dosage of 0.07% by weight of cement binder. The results indicate that mechanical strengths of cement mortars at 7 and 28 days considerably depend on the size of PRG. The mixes with size 56 µm and 73 µm show significant influence on both compressive and tensile strengths of cement mortars, which increase approximately 34.3% and 30.1% at 28-day compressive strengths, and 26.9% and 38.6% at 28-day tensile strengths, respectively. On the other hand, the mix with size 43 µm of PRG addition exhibits a significant increase only in tensile strength, and there are no significant effects on either compressive strengths or tensile strengths of the mix containing 5 µm particles. The observed enhancement in the mechanical properties of cement mortars by large PRG sizes is attributed to the improvement of cement hydration level, the reduction of cement particles’ distance in cement gels because of the effect of van der Waals forces between PRG sheets, and the mechanical adhesion forces between PRG sheets and cement gels. The results from this study indicate that PRG is not only a promising additive in practical application for building materials to improve the current drawbacks of cement composites, but also a feasible option to support the reduction of cement mass used in cement composites, which could reduce the CO₂ footprint and amount of CO₂ emission into the atmosphere.Van Dac Ho, Ching-Tai Ng, Togay Ozbakkaloglu, Andy Goodwin, Craig McGuckin, Ramesh U. Karunagaran, Dusan Losi

Real-Time Cavity Fault Prediction in CEBAF Using Deep Learning

Data-driven prediction of future faults is a major research area for many industrial applications. In this work, we present a new procedure of real-time fault prediction for superconducting radio-frequency (SRF) cavities at the Continuous Electron Beam Accelerator Facility (CEBAF) using deep learning. CEBAF has been afflicted by frequent downtime caused by SRF cavity faults. We perform fault prediction using pre-fault RF signals from C100-type cryomodules. Using the pre-fault signal information, the new algorithm predicts the type of cavity fault before the actual onset. The early prediction may enable potential mitigation strategies to prevent the fault. In our work, we apply a two-stage fault prediction pipeline. In the first stage, a model distinguishes between faulty and normal signals using a U-Net deep learning architecture. In the second stage of the network, signals flagged as faulty by the first model are classified into one of seven fault types based on learned signatures in the data. Initial results show that our model can successfully predict most fault types 200 ms before onset. We will discuss reasons for poor model performance on specific fault types

IL-22 mediates goblet cell hyperplasia and worm expulsion in intestinal helminth infection.

Type 2 immune responses are essential in protection against intestinal helminth infections. In this study we show that IL-22, a cytokine important in defence against bacterial infections in the intestinal tract, is also a critical mediator of anti-helminth immunity. After infection with Nippostrongylus brasiliensis, a rodent hookworm, IL-22-deficient mice showed impaired worm expulsion despite normal levels of type 2 cytokine production. The impaired worm expulsion correlated with reduced goblet cell hyperplasia and reduced expression of goblet cell markers. We further confirmed our findings in a second nematode model, the murine whipworm Trichuris muris. T.muris infected IL-22-deficient mice had a similar phenotype to that seen in N.brasiliensis infection, with impaired worm expulsion and reduced goblet cell hyperplasia. Ex vivo and in vitro analysis demonstrated that IL-22 is able to directly induce the expression of several goblet cell markers, including mucins. Taken together, our findings reveal that IL-22 plays an important role in goblet cell activation, and thus, a key role in anti-helminth immunity

MUC1 Limits Helicobacter pylori Infection both by Steric Hindrance and by Acting as a Releasable Decoy

The bacterium Helicobacter pylori can cause peptic ulcer disease, gastric adenocarcinoma and MALT lymphoma. The cell-surface mucin MUC1 is a large glycoprotein which is highly expressed on the mucosal surface and limits the density of H. pylori in a murine infection model. We now demonstrate that by using the BabA and SabA adhesins, H. pylori bind MUC1 isolated from human gastric cells and MUC1 shed into gastric juice. Both H. pylori carrying these adhesins, and beads coated with MUC1 antibodies, induced shedding of MUC1 from MKN7 human gastric epithelial cells, and shed MUC1 was found bound to H. pylori. Shedding of MUC1 from non-infected cells was not mediated by the known MUC1 sheddases ADAM17 and MMP-14. However, knockdown of MMP-14 partially affected MUC1 release early in infection, whereas ADAM17 had no effect. Thus, it is likely that shedding is mediated both by proteases and by disassociation of the non-covalent interaction between the α- and β-subunits. H. pylori bound more readily to MUC1 depleted cells even when the bacteria lacked the BabA and SabA adhesins, showing that MUC1 inhibits attachment even when bacteria cannot bind to the mucin. Bacteria lacking both the BabA and SabA adhesins caused less apoptosis in MKN7 cells than wild-type bacteria, having a greater effect than deletion of the CagA pathogenicity gene. Deficiency of MUC1/Muc1 resulted in increased epithelial cell apoptosis, both in MKN7 cells in vitro, and in H. pylori infected mice. Thus, MUC1 protects the epithelium from non-MUC1 binding bacteria by inhibiting adhesion to the cell surface by steric hindrance, and from MUC1-binding bacteria by acting as a releasable decoy