Empirical Distribution Models for Slenderness and Aspect Ratios of Core Particles of Particulate Wood Composites

Particle geometry was characterized for particleboard furnish prepared through hydrolysis of finished commercial particleboard procured from six Canadian plants. Particles samples were screened into seven particle size classes. Particles retained on 0.5-mm mesh were considered core particles and further partitioned into core-fine, medium, and coarse. Individual particles were then randomly selected for geometrical characterization and distribution fitting. About 80% of all screened particles by mass were between mesh sizes of 0.5 and 2 mm. There were significant differences in percentage screen masses of all particle sizes between plants. Masses of particle size greater than 1 mm of panels from two plants were significantly higher than the rest (0.05 α-level), whereas another plant had the highest mass of particle sizes retained on the 2-mm mesh. Particles retained on the 1-mm mesh showed the largest percentage mass variation among all plants. It was found that aspect ratio was a better geometrical indicator for predicting screw withdrawal resistance than any of the absolute dimensions, and increase in core-fine particles increases internal bond strength. Based on maximum likelihood and Akaike's Information Criterion, a log normal distribution was the best fit for all geometrical descriptors of most particle types; gamma and two-parameter Weibull were better fits for length and aspect ratio for most medium particles with gamma being the better of the two

Improving Core Bond Strength of Particleboard Through Particle Size Redistribution

Novel particleboard furnish mixtures were formulated to improve the core-bonding and screw-holding of industrial particleboard without increasing resin content or board density. Single-layer (uniform vertical density with core furnish only) and conventional 3-layer particleboards were manufactured at two density levels from four novel mixes plus control (unscreened industrial core furnish). Board mean and core density, internal bond strength, edge screw withdrawal resistance, and moduli of rupture and elasticity were measured.The core of commercial furniture-grade particleboard appears to contain too many fine particulates and insufficient coarser particles. Uniform density profile single-layer boards containing novel mixes with higher-coarse (>2 mm) and lower-fines

Coagulation factors and natural anticoagulants as surrogate markers of preeclampsia and its subtypes: A case-control study in a Ghanaian population

Preeclampsia (PE) is associated with endothelial injury and hemostatic abnormalities. However, the diagnostic role of coagulation parameters and natural anticoagulants in predicting PE has not been explored in Ghana. This study assessed plasma levels of these factors as surrogate markers of PE and its subtypes. This case-control study included 90 women with PE (cases) and 90 normotensive pregnant women (controls). Blood samples were drawn for the estimation of complete blood count and coagulation tests. The prothrombin time (PT), activated partial thromboplastin time (APTT), and the calculation of the international normalized ratio (INR) were determined by an ACL elite coagulometer while the levels of protein C (PC), protein S (PS), antithrombin III (ATIII), and D-dimers were also measured using the solid-phase sandwich enzyme-linked immunosorbent assay (ELISA) method. All statistical analyses were performed using the R Language for Statistical Computing. Results showed significantly (p \u3c .05) shortened APTT (28.25 s) and higher D-dimer levels (1219.00 ng/mL) among PE women, as well as low levels of PC (1.02 g/mL), PS (6.58 g/mL), and ATIII (3.99 ng/mL). No significant difference was found in terms of PT and INR. From the receiver operating characteristic analysis, PC, PS, and ATIII could significantly predict PE and its subtypes at certain cutoffs with high accuracies (area under the curve [AUC] ≥ 0.70). Most women with PE are in a hypercoagulable state with lower natural anticoagulants. PC, PS, and ATIII are good predictive and diagnostic markers of PE and its subtypes (early-onset PE [EO-PE] and late-onset PE [LO-PE]) and should be explored in future studies

Quality of glycemic control in type 2 diabetes mellitus (T2DM) and its association with markers of coagulation and inhibitors of fibrinolysis: A case–control study in the upper west region, Ghana

Background and Aims: Type 2 diabetes mellitus (T2DM) individuals are at a higher risk of developing diabetes complications, with approximately 80% complication-related mortality. The increased morbidity and mortality among T2DM patients are partly due to dysregulated hemostasis. This study determined the quality of glycemic control in T2DM and its association with markers of coagulation and inhibitors of fibrinolysis. Methods: This case–control study recruited 90 participants involving: 30 T2DM patients with good glycemic control, 30 with poor glycemic control, and 30 nondiabetic subjects as controls at a Municipal Hospital in Ghana. Fasting blood glucose, glycated hemoglobin, activated partial thromboplastin time (APTT), prothrombin time (PT), calculated international normalized ratio (INR), and full blood count (FBC) were determined for each respondent. Plasma levels of plasminogen activator inhibitor-1 (PAI-1) and thrombin activatable fibrinolysis inhibitor (TAFI) were determined using the solid-phase sandwich enzyme-linked immunosorbent assay method. Data were analyzed using R language software. Results: Plasma PAI-1 antigen levels were significantly higher in the participants with poor glycemic control as compared to participants with good glycemic control (p \u3c 0.0001). There was no significant difference in plasma TAFI levels between the participants with poor glycemic control as compared to participants with good glycemic control (p = 0.900). T2DM patients had significantly shorter APTT, PT, and INR than controls (p \u3c 0.05). At a cut-off of ≥ 161.70 pg/μL, PAI was independently associated with increasing odds (adjusted odds ratio = 13.71, 95% confidence interval: 3.67–51.26, p \u3c 0.0001) of poor glycemic control and showed the best diagnostic accuracy for poor glycemic control (area under the curve = 0.85, p \u3c 0.0001). Conclusion: PAI-1 levels were significantly increased in T2DM with poor glycemic control and emerged as the best predictor for poor glycemic control. Good glycemic management to control the plasma levels of PAI-1 is required to prevent hypercoagulability and thrombotic disorders

Feasibility of a New Hybrid Wood Composite Comprising Wood Particles and Strands

Hybrid boards consisting of a strand core and particleboard faces (PSP) with three different shelling ratios were designed using strand sizes from dust to 4.5 mm mesh and normal particleboard face material. Flexural properties, internal bond (IB) strength, screw withdrawal resistance (SWR), hardness, and dimensional properties were measured. The modulus of elasticity of these hybrid boards was 25% greater than that specified by the ANSI standard for M3 industrial particleboard. An increase in modulus of rupture of approximately 50% was recorded for boards containing 60% strands compared with control particleboard without strands. Hybridization also accounted for a decrease in linear expansion compared with particleboard. However, IB strength decreased and SWR values showed no significant change. Therefore, with improved core properties, PSP has the potential to replace M3 particleboard

Effect of Extended Mat Open Assembly Time on Properties of OSB Bonded With PMDI

In this study, the effect of increasing mat open assembly time on the strength properties of oriented strandboards bonded with polymeric methylene diphenol di-isocyanate (pMDI) resin was examined. Isocyanates are more sensitive to open assembly times than other resin systems such as phenol formaldehyde (PF), and the storage capacity of pMDI-blended wood furnish is believed to be no more than about 5 h. On the other hand, previous research works on bonding of wood elements with pMDI allude to the growth of an interpenetrating network (IPN) of cross-linked polyurea as being responsible for the high bonding capacity with pMDI and that this is enhanced with long pre-cure times (greater than 10-15 h). There was no evidence that this effect enhances the strength of OSB made from shortleaf pine, as boards pressed after a delay of 10 or more hours after blending were significantly lower in internal bond (IB) strength than those pressed within half an hour of blending. However, after a reduction of approximately 28% between 0 and 10 h, IB remained relatively stable with open assembly times up to 18 h, suggesting the potential for recycling such strands by partial substitution of them with freshly blended strands. The discrepancy between our findings and the pMDI bonding theory based on previous small-scale laboratory experiments was thought to have arisen from differences in resin distribution on the strands due to their different methods of application, and the cure temperature and moisture conditions in the core of boards being sub-optimal for the formation of an extensive network of fully cross-linked polyurea

Characteristics of HIV-2 and HIV-1/HIV-2 Dually Seropositive Adults in West Africa Presenting for Care and Antiretroviral Therapy: The IeDEA-West Africa HIV-2 Cohort Study.

HIV-2 is endemic in West Africa. There is a lack of evidence-based guidelines on the diagnosis, management and antiretroviral therapy (ART) for HIV-2 or HIV-1/HIV-2 dual infections. Because of these issues, we designed a West African collaborative cohort for HIV-2 infection within the framework of the International epidemiological Databases to Evaluate AIDS (IeDEA).We collected data on all HIV-2 and HIV-1/HIV-2 dually seropositive patients (both ARV-naive and starting ART) and followed-up in clinical centres in the IeDEA-WA network including a total of 13 clinics in five countries: Benin, Burkina-Faso Côte d'Ivoire, Mali, and Senegal, in the West Africa region.Data was merged for 1,754 patients (56% female), including 1,021 HIV-2 infected patients (551 on ART) and 733 dually seropositive for both HIV-1 and HIV 2 (463 on ART). At ART initiation, the median age of HIV-2 patients was 45.3 years, IQR: (38.3-51.7) and 42.4 years, IQR (37.0-47.3) for dually seropositive patients (p = 0.048). Overall, 16.7% of HIV-2 patients on ART had an advanced clinical stage (WHO IV or CDC-C). The median CD4 count at the ART initiation is 166 cells/mm(3), IQR (83-247) among HIV-2 infected patients and 146 cells/mm(3), IQR (55-249) among dually seropositive patients. Overall, in ART-treated patients, the CD4 count increased 126 cells/mm(3) after 24 months on ART for HIV-2 patients and 169 cells/mm(3) for dually seropositive patients. Of 551 HIV-2 patients on ART, 5.8% died and 10.2% were lost to follow-up during the median time on ART of 2.4 years, IQR (0.7-4.3).This large multi-country study of HIV-2 and HIV-1/HIV-2 dual infection in West Africa suggests that routine clinical care is less than optimal and that management and treatment of HIV-2 could be further informed by ongoing studies and randomized clinical trials in this population