Edge and face linear vibration welding of wood panels

Edge-to-edge linear vibration welding of particle- board, OSB, MDF and plywood gives better strength than face-to-face panel welding. In general, the edge-to-edge weldline is slightly weaker than the panels itself. The face- to-face weldline is stronger than the strength of the material in the same direction

Feasibility and safety of a 6-month exercise program to increase bone and muscle strength in children with juvenile idiopathic arthritis

Background: Arthritis in childhood can be associated with muscle weakness around affected joints, low bone mass and low bone strength. Exercise is recognized as an important part of management of children with juvenile idiopathic arthritis (JIA) but the exercise prescription to best promote bone and muscle health is unknown. We therefore aimed to: 1. assess feasibility and safety of a 6-month home- and group-based exercise program for children with JIA; 2. estimate the effect of program participation on bone mass and strength, muscle function and clinical outcomes and 3. determine if any positive changes in bone and muscle outcomes are maintained 6 months later. Methods: We recruited 24 children with JIA who were part of the Linking Exercise, Physical Activity and Pathophysiology in Childhood Arthritis (LEAP) study to participate in a 6-month home-based exercise program involving jumping and handgrip exercises, resistance training and one group exercise session per month. We assessed lumbar spine bone mass (dual energy X-ray absorptiometry), distal tibia and radius bone microarchitecture and strength (high-resolution peripheral quantitative computed tomography), muscle function (jumping mechanography, dynamometry) and clinical outcomes (joint assessment, function, health-related quality of life) at baseline, 6- and 12-months. Adherence was assessed using weekly activity logs. Results: Thirteen children completed the 6-month intervention. Participants reported 9 adverse events and post-exercise pain was rare (0.4%). Fatigue improved, but there were no other sustained improvements in muscle, bone or clinical outcomes. Adherence to the exercise program was low (47%) and decreased over time. Conclusion: Children with JIA safely participated in a home-based exercise program designed to enhance muscle and bone strength. Fatigue improved, which may in turn facilitate physical activity participation. Prescribed exercise posed adherence challenges and efforts are needed to address facilitators and barriers to participation in and adherence to exercise programs among children with JIA. Trial registration: Data of the children with JIA are from the LEAP study (Canadian Institutes of Health Research (CIHR; GRANT# 107535). http://www.leapjia.com/

Predicting which children with juvenile idiopathic arthritis will not attain early remission with conventional treatment: Results from the Reacch-out cohort

Objective. To estimate the probability of early remission with conventional treatment for each child with juvenile idiopathic arthritis (JIA). Children with a low chance of remission may be candidates for initial treatment with biologics or triple disease-modifying antirheumatic drugs (DMARD). Methods. We used data from 1074 subjects in the Research in Arthritis in Canadian Children emphasizing Outcomes (ReACCh-Out) cohort. The predicted outcome was clinically inactive disease for ≥ 6 months starting within 1 year of JIA diagnosis in patients who did not receive early biologic agents or triple DMARD. Models were developed in 200 random splits of 75% of the cohort and tested on the remaining 25% of subjects, calculating expected and observed frequencies of remission and c-index values. Results. Our best Cox logistic model combining 18 clinical variables a median of 2 days after diagnosis had a c-index of 0.69 (95% CI 0.67-0.71), better than using JIA category alone (0.59, 95% CI 0.56-0.63). Children in the lowest probability decile had a 20% chance of remission and 21% attained remission; children in the highest decile had a 69% chance of remission and 73% attained remission. Compared to 5% of subjects identified by JIA category alone, the model identified 14% of subjects as low chance of remission (probability \u3c 0.25), of whom 77% failed to attain remission. Conclusion. Although the model did not meet our a priori performance threshold (c-index \u3e 0.70), it identified 3 times more subjects with low chance of remission than did JIA category alone, and it may serve as a benchmark for assessing value added by future laboratory/imaging biomarkers

In vitro and in vivo models define a molecular signature reference for human embryonic notochordal cells

Understanding the emergence of human notochordal cells (NC) is essential for the development of regenerative approaches. We present a comprehensive investigation into the specification and generation of bona fide NC using a straightforward pluripotent stem cell (PSC)-based system benchmarked with human fetal notochord. By integrating in vitro and in vivo transcriptomic data at single-cell resolution, we establish an extended molecular signature and overcome the limitations associated with studying human notochordal lineage at early developmental stages. We show that TGF-β inhibition enhances the yield and homogeneity of notochordal lineage commitment in vitro. Furthermore, this study characterizes regulators of cell-fate decision and matrisome enriched in the notochordal niche. Importantly, we identify specific cell-surface markers opening avenues for differentiation refinement, NC purification, and functional studies. Altogether, this study provides a human notochord transcriptomic reference that will serve as a resource for notochord identification in human systems, diseased-tissues modeling, and facilitating future biomedical research

Experimental study of dense pyroclastic density currents using sustained, gas-fluidized granular flows

© 2014, Springer-Verlag Berlin Heidelberg. We present the results of laboratory experiments on the behaviour of sustained, dense granular flows in a horizontal flume, in which high-gas pore pressure was maintained throughout the flow duration by continuous injection of gas through the flume base. The flows were fed by a sustained (0.5–30 s) supply of fine (75 ± 15 μm) particles from a hopper; the falling particles impacted an impingement surface at concentrations of ~3 to 45 %, where they densified rapidly to generate horizontally moving, dense granular flows. When the gas supplied through the flume base was below the minimum fluidization velocity of the particles (i.e. aerated flow conditions), three flow phases were identified: (i) an initial dilute spray of particles travelling at 1–2 m s−1, followed by (ii) a dense granular flow travelling at 0.5–1 m s−1, then by (iii) sustained aggradation of the deposit by a prolonged succession of thin flow pulses. The maximum runout of the phase 2 flow was linearly dependent on the initial mass flux, and the frontal velocity had a square-root dependence on mass flux. The frontal propagation speed during phase 3 had a linear relationship with mass flux. The total mass of particles released had no significant control on either flow velocity or runout in any of the phases. High-frequency flow unsteadiness during phase 3 generated deposit architectures with progradational and retrogradational packages and multiple internal erosive contacts. When the gas supplied through the flume base was equal to the minimum fluidization velocity of the particles (i.e. fluidized flow conditions), the flows remained within phase 2 for their entire runout, no deposit formed and the particles ran off the end of the flume. Sustained granular flows differ significantly from instantaneous flows generated by lock-exchange mechanisms, in that the sustained flows generate (by prolonged progressive aggradation) deposits that are much thicker than the flowing layer of particles at any given moment. The experiments offer a first attempt to investigate the physics of the sustained pyroclastic flows that generate thick, voluminous ignimbrites

Blau Syndrome-Associated Uveitis: Preliminary Results From an International Prospective Interventional Case Series

PURPOSE: Provide baseline and preliminary follow-up results in a 5-year longitudinal study of Blau syndrome. DESIGN: Multicenter, prospective interventional case series. METHODS: Baseline data from 50 patients from 25 centers worldwide, and follow-up data for patients followed 1, 2, or 3 years at the end of study enrollment. Ophthalmic data were collected at baseline and yearly visits by means of a standardized collection form. RESULTS: Median age at onset of eye disease was 60 months and duration of eye disease at baseline 145 months. At baseline 38 patients (78%) had uveitis, which was bilateral in 37 (97%). Eight patients (21%) had moderate to severe visual impairment. Panuveitis was found in 38 eyes (51%), with characteristic multifocal choroidal infiltrates in 29 eyes (39%). Optic disc pallor in 9 eyes (12%) and peripapillary nodules in 9 eyes (12%) were the commonest signs of optic nerve involvement. Active anterior chamber inflammation was noted in 30 eyes (40%) at baseline and in 16 (34%), 17 (57%), and 11 (61%) eyes at 1, 2, and 3 years, respectively. Panuveitis was associated with longer disease duration. At baseline, 56 eyes (75%) were on topical corticosteroids. Twenty-six patients (68%) received a combination of systemic corticosteroids and immunomodulatory therapy. CONCLUSIONS: Blau uveitis is characterized by progressive panuveitis with multifocal choroiditis, resulting in severe ocular morbidity despite continuous systemic and local immunomodulatory therapy. The frequency and severity of Blau uveitis highlight the need for close ophthalmologic surveillance as well as a search for more effective therapies

Beyond What Meets the Eye: Imaging and Imagining Wood Mechanical–Structural Properties

Abstract: Wood presents a hierarchical structure, containing features at all length scales: from the tracheids or vessels that make up its cellular structure, through to the microfibrils within the cell walls, down to the molecular architecture of the cellulose, lignin, and hemicelluloses that comprise its chemical makeup. This structure renders it with high mechanical (e.g., modulus and strength) and interesting physical (e.g., optical) properties. A better understanding of this structure, and how it plays a role in governing mechanical and other physical parameters, will help to better exploit this sustainable resource. Here, recent developments on the use of advanced imaging techniques for studying the structural properties of wood in relation to its mechanical properties are explored. The focus is on synchrotron nuclear magnetic resonance spectroscopy, X‐ray diffraction, X‐ray tomographical imaging, Raman and infrared spectroscopies, confocal microscopy, electron microscopy, and atomic force microscopy. Critical discussion on the role of imaging techniques and how fields are developing rapidly to incorporate both spatial and temporal ranges of analysis is presented

Predicting the Thermal Behaviour of Wood During Linear Welding Using the Finite Element Method

A numerical model to simulate the temperature behaviour of wood welding samples during the welding process was developed to understand the influence of material parameters on the welding temperature. A fi- nite element method and the CAST3M software were used to simulate and model the temperature changes during welding of beech wood. This model takes into account the different properties of the wood welded bondline, the geometry of the sample and the external conditions. The energy produced by the friction welding of the wood samples was determined from infrared thermography measurements for the welding process and inputted into the model. The comparison between the predicted and experimental results shows that the model is reliable. The applied pressure, the vibration, the extrusion of material and the chemical reactions, particularly exothermic reactions, are not taken into account in this model and thus probably ex- plain the differences existing between actual and simulated values. However, this numerical simulation gives information on the distribution of the temperature in the sample. The model predicted that the temperature difference between the centre and the side of the sample is not higher than 4◦C. This means that the border effects are negligible. The model was tested for different welding times. According to the model a heat flow about 70 kW/m2 is necessary at the welding line to ensure a satisfactory bonding for the chosen sample geometry. Welding of large wood pieces has also been simulated in this study

Temperature and density distribution in mechanical vibration wood welding

Nondestructive evaluation of wood joints welded by linear vibra- tion welding was performed with an infrared (IR) thermography technique, which allowed the maximal and average peak temperature profile/distribution to be measured. The density profile/distribution at the joint interface was measured by X-ray microdensitometry. The results show that the width of the welded zone also varies as a function of the maximum temperature reached during welding and that the maximum temperature reached at the ends of the specimens is lower than that obtained in the central part of the specimens