Prediction of Internal Bond Strength in Particleboard from Screw Withdrawal Resistance Models

Density, internal bond (IB) strength, and screw withdrawal resistance (SWR) data from 20 MS and M2 grade particleboards from two Canadian manufacturers were used to examine the correlations between face and edge SWR, and density and IB. SWR data were matched with previously published models for SWR as functions of density or IB, which were only reliable if they contained terms for screw dimensions and embedment depth. There was little or no correlation between the face or edge SWR of particleboards and their density, but sufficiently good correlation with IB (r2 > 0.7) to support the development of SWR tests as a useful, rapid estimate of IB of particleboard panels. The proposed models are internally calibrated to 5/8-in.-thick board only and need to be developed and tested on other particleboards

Manufacture of Wood-Cement Composites from Acacia Mangium. Part II. Use of Accelerators in the Manufacture of Wood-Wool Cement Boards from A. Mangium

In the second paper in this series, we test the hypothesis that cement-setting accelerators with the ability to chelate phenolic extractives will be more effective at improving the physical properties of wood-wool cement boards made from the heartwood of Acacia mangium than conventional accelerators. Furthermore, we assess whether the use of chelating accelerators will allow boards with acceptable properties to be manufactured from A. mangium wood-wool that has not been subjected to preliminary aqueous extraction to remove phenolic extractives. Batches of wood-wool from A. mangium containing approximately 75% heartwood were either soaked in water or used in their native form. The batches were then treated with an aqueous solution containing an inorganic compound (generally 0.05 or 0.1 M) selected for its ability to accelerate the hydration of Portland cement, and in the case of 5 of the 11 compounds tested, chelate phenolic extractives. Individual wood-wool cement boards were manufactured from each treated batch of wood-wool and tested for their dry and wet bending strength (MOR), stiffness (MOE), and water absorption properties. Boards made from untreated or water-soaked wood-wool acted as controls. The MOR and MOE of boards made from unsoaked A. mangium wood-wool and treated with the chelating accelerators tin or ferric chloride at 0.1 M concentration were 10.8 and 10.9 MPa and 2256 and 2178 MPa, respectively. These same boards showed less than 5% thickness swelling after 24-h immersion in water. In contrast most of the boards containing a conventional non-chelating accelerator had no structural integrity. The combination of a chelating accelerator and a conventional accelerator was particularly effective at improving the physical properties of boards made from unsoaked wood-wool. We conclude that wood-wool cement boards with acceptable physical properties can be manufactured from A. mangium heartwood by treating wood-wool with inorganic compounds that have the ability to chelate phenolic extractives and accelerate the hydration of Portland cement. Our findings could eliminate the need to pre-soak A. mangium wood-wool in water during the manufacture of wood-wool cement boards and may have broader relevance to the manufacture of wood-wool cement boards from other hardwood species containing phenolic extractives

Risk factors for failure of outpatient parenteral antibiotic therapy (OPAT) in infective endocarditis

Objectives: To identify risk factors for failure of outpatient antibiotic therapy (OPAT) in infective endocarditis (IE). Patients and methods: We identified IE cases managed at a single centre over 12 years from a prospectively maintained database. ‘OPAT failure’ was defined as unplanned readmission or antibiotic switch due to adverse drug reaction or antibiotic resistance. We analysed patient and disease-related risk factors for OPAT failure by univariate and multivariate logistic regression. We also retrospectively collected follow-up data on adverse disease outcome (defined as IE-related death or relapse) and performed Kaplan–Meier survival analysis up to 36 months following OPAT. Results: We identified 80 episodes of OPAT in IE. Failure occurred in 25/80 episodes (31.3%). On multivariate analysis, cardiac or renal failure [pooled OR 7.39 (95% CI 1.84–29.66), P = 0.005] and teicoplanin therapy [OR 8.69 (95% CI 2.01–37.47), P = 0.004] were independently associated with increased OPAT failure. OPAT failure with teicoplanin occurred despite therapeutic plasma levels. OPAT failure predicted adverse disease outcome up to 36 months (P = 0.016 log-rank test). Conclusions: These data caution against selecting patients with endocarditis for OPAT in the presence of cardiac or renal failure and suggest teicoplanin therapy may be associated with suboptimal OPAT outcomes. Alternative regimens to teicoplanin in the OPAT setting should be further investigated

Transverse Permeability of OSB. Part II. Modeling the Effects of Density and Core Fines Content

In this work a simple rule of mixtures model to characterize the permeability of an OSB composite as a function of fines contents and density is presented. Strands and fines in the core of the board are considered to lie between two extremes, either stacked in a series configuration (series model) or side by side in a parallel configuration (parallel model), with the permeability of the composite, Ksystem, being a function of relative permeabilities of the series and parallel models. Equations for the permeability of these two configurations, Kparallel and Kseries, are developed as functions of the known permeability of 100% strands, Ks, and 100% fines, Kf, and the mass fraction of fines, Mf. Data on the permeability of the core of OSB compressed to three density classes and made with 0 and 100% fines content are used to determine the permeability of the parallel and series models, respectively. The series coefficient, α, which represents the contribution from the series model, is determined using least squares fits to the permeability data for different target densities and 25%, 50%, and 75% fines contents. α was fairly consistent, ranging from 0.47 to 0.49 for these fines contents. Kparallel increases linearly with increasing fines content and Kseries increases exponentially, in accord with the actual data. The data for the low and medium target density boards were well described by the Ksystem predictions, whereas the model underestimates the permeability of boards containing 75% or 100% fines and compressed to high target density. The model was most sensitive to changes in Mf, Kf, and Ks, with other parameters, α and density ratio (ρs/ρf), having smaller effects. The proposed model is general and could be applied to other composites of mixed particle sizes such as particleboard

Permeability of OSB. Part I. The Effects of Core Fines Content and Mat Density on Transverse Permeability

This paper reports on the effects of density and core fines content on the transverse permeability, K, of oriented strandboard (OSB), with the aim of using fines generated during the log stranding process to improve mat permeability and possibly press efficiency. Forty-five OSB panels were made in the laboratory containing five levels of fines content (0, 25, 50, 75, and 100%) and compressed to three target density levels (low—450, medium—550, and high—650 kg/m3). Both density and fines content and their interaction significantly influenced Kcore, which increased exponentially with fines content at each density level. Above 75% fines, density level no longer had any significant effect on Kcore, indicating that as the mat is compressed, the presence of fines maintains a more interconnected void system through which gas can pass. The rate of heat transfer to the core was affected by board thickness but contrary to expectations, not by fines content. Fines content did, however, affect the accumulation of gas pressure in the high target density heavily compressed boards; maximum core gas pressure was significantly reduced if core fines content was greater than 50%

Measuring Heart Rate Variability Using Commercially Available Devices in Healthy Children: A Validity and Reliability Study

Heart rate variability (HRV) is an accepted method for determining autonomic nervous system activity and cardiovascular risk in various populations. This study assessed the validity and reliability of a commercially available finger photoplethysmography (PPG) system for measuring pediatric HRV in a real-world setting. Sixteen healthy children (4.06 ± 0.58 years) were recruited. The PPG system was compared to the Polar H10 heart rate (HR) sensor validated against ECG (gold standard) for HRV measurement. Seated short-term resting R-R intervals were recorded simultaneously using both systems. Recordings were performed on 3 days at the participants’ school. Paired t-tests, effect sizes and Bland–Altman analyses determined the validity of the PPG system. The relative and absolute reliability of both systems were calculated. No HRV parameters were valid for the PPG system. Polar H10 yielded moderate (0.50–0.75) to good (0.75–0.90) relative reliability with R-R intervals and the standard deviation of instantaneous and continuous R-R variability ratio showing the best results (ICCs = 0.84). Polar H10 displayed better absolute reliability with the root mean square of successive differences, R-R intervals and HR showing the lowest values (TEM% < 12%). The use of the Polar H10 and not the PPG system is encouraged for HRV measurement of young children in an educational real-world setting

Properties and Wood Bonding Capacity of Nanoclay-Modified Urea and Melamine Formaldehyde Resins

Urea formaldehyde (UF) and melamine formaldehyde (MF) thermosetting resins were substituted with up to 6% nanoclay (organic modified Cloisite®30B and unmodified Nanofil® 116; Southern Clay Ltd, Austin, TX) and assessed for mixing and curing compatibility using X-ray diffraction, differential scanning calorimetry, wood lap-shear tests, and particleboard strength tests. Cloisite® 30B exfoliated fully in both resin types, whereas Nanofil® 116 showed increased spacing between platelets (intercalation) but not exfoliation. Nanoclays improved bonding strength of MF more than UF resin, and 2% nanoclay with a coupling agent in MF significantly enhanced particleboard bonding strength. Also, thickness swelling of particleboard in water decreased with up to 6% nanoclay. To decrease costs, MF resin could potentially be substituted by up to 6% nanoclay with no detrimental effect on properties

Evaluating the effects of lymphoedema management strategies on functional status and health-related quality of life following treatment for head and neck cancer: Protocol for a systematic review

Introduction/Background: Patients living with and after head and neck cancer often experience treatment-related consequences. Head and neck lymphoedema can be described as a common chronic side effect of head and neck cancer and recognised as a contributing factor to impairment of functional status, symptom burden and health-related quality of life. The effects of head and neck lymphoedema can limit patients’ involvement in daily activities and alter their appearance, increasing symptom burden and negatively affecting health-related quality of life. Objective: The protocol outlines the rationale and aims for the systematic review. The main aim of the systematic review is to identify and systematically synthesise the literature on the effectiveness of head and neck lymphoedema management strategies, on both function status and health-related quality of life for head and neck cancer patients. Methods and analysis: This protocol will be conducted according to the PRISMA-P guidelines. Electronic databases will be systematically searched using MEDLINE via Ovid and PubMed, CINAHL, Cochrane Central Register of Controlled Trials and Scopus. Inclusion criteria will involve intervention studies for head and neck lymphoedema management, English language, and adult human participants following head and neck cancer. The software Covidence will be used to export, manage, and screen results. Risk of bias and quality will be assessed in included studies using the Cochrane Handbook of Systematic Reviews of Intervention risk of bias and GRADE tools. A meta-analysis will be performed if there are sufficient homogenous studies. Alternatively, a narrative synthesis will be completed on study findings. Ethics and dissemination: No ethical approval is required as the study does not involve patient and public involvement. The findings of the review will be disseminated in conferences and submitted for approval to be published in a peer-reviewed journal. Prospero registration number: CRD42022378417. (S1 Appendix)