In this study, three-layer particleboards are produced from a mixture of sunflower stalks (Helianthus annuus L.) and poplar wood (Populus alba L.) at certain ratios utilizing urea-formaldehyde (UF) adhesives. Panels with a density of 0.7 g/cm 3are manufactured with the ratios of 25, 50, and 75 percent particles from sunflower stalks or poplar. For comparison, panels are solely manufactured with sunflower stalks and poplar wood. All panels are tested for physical properties (thickness swelling (TS) and water absorption (WA)) and mechanical properties (internal bond (IB), modulus of elasticity (MOE), modulus of rupture (MOR), and screw holding capacity (SHC)). Results show that all the panels provide properties required by the Turkish standards for general purpose-use particleboards. Furthermore, properties of the panels have improved with the rising percentage of poplar particles in the panels. The combination of sunflower stalks and poplar particles can be used at different ratios and the resulting panels can be utilized in indoor applications for general purposes such as furniture manufacturing. This result may prove that sunflower stalks can be an alternative raw material for the manufacture of particleboards.

In this study, we determined the flexural properties and tensile shear strength of five-ply plywood panels produced with eucalyptus (Eucalyptus grandis), beech (Fagus orientalis), and hybrid poplar (Populus x euramericana) using urea-formaldehyde (UF), melamine-urea-formaldehyde (MUF) and phenol-formaldehyde (PF) adhesives. Flexural properties were tested on both parallel and perpendicular to grain samples. Tensile shear-strength tests were conducted on four glue lines of the plywood panels, and the effects of species of trees, type of adhesives, and direction of load were determined. The results of variance analyses showed that the effects of species of trees, direction of load, and type of adhesive on flexural properties were significant, but it was determined by specific flexural properties that the effect of the type of adhesive was based on the density of the plywood. In addition, as a result of findings, it can be said that specific mechanical properties may be a good predictor for comparative studies.

Heat treatment can be used to improve the physical properties and durability of wood. The results achieved by heat treatment can be affected significantly by various factors. Juvenile wood and mature wood from the same trunk have different properties, and the effects of heat treatment on their physical properties have not been well defined. Thus, a study to determine the differences in the physical properties of juvenile wood and mature wood of E. grandis after heat treatment was conducted. Samples of both types of wood were treated at temperatures of 120, 150, and 180 o C for durations of 4, 6, and 8 h. The results showed that the physical properties of juvenile and mature wood, e.g., swelling, moisture content, and fiber saturation point, did not decrease to the same extent. Mass loss of mature wood was higher than that of juvenile wood. Generally, percentage decreases of volumetric swelling, moisture content, and fiber saturation point of juvenile wood were more affected than those of mature wood.

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In recent years, there is an increased research interest for plants which are natural sources of antioxidants. Lepidium sativum Subsp spinescens L., commonly found in South West Asia, is a plant known as a healthy nutritional source containing bio-molecules that carry anti-hypertensive, hypoglycemic, anti-asthmatic, antispasmodic, hepato-protective, chemoprotective, anti-inflammatory and anti-oxidant effects. In this study, we aimed to investigate the antioxidant content and activity of Lepidium sativum Subsp spinescens L. methanol extract on cancer cells. Methanol extract of dried Lepidium sativum Subsp spinescens L. was prepared. Total amount of phenolic compounds was determined by Slinkard and Singleton method using Folin-Ciocalteu reagent. Total flavonoid amount was determined according to Zhishen method. Antioxidant activity of the extract was evaluated by CUPRAC and ABTS radical scavenging activity assays. Cytotoxic effects of the plant extract on colon and endometrium cancer cells, and human peripheral lymphocyte cells were investigated in vitro by MTT and neutral red assays. Furthermore, the plant extract was investigated for necrotic effects by LDH assay; apoptotic activity by DNA ladder fragmentation, ELISA and acridine orange/ethidium bromide staining; and genotoxic effect by comet assay methods. Methanol extract of Lepidium sativum Subsp spinescens L. was found to have a high content of phenolic and flavonoid compounds. The extract showed significant antioxidant activity and also cytotoxic activity on colon and endometrium cancer cells in a concentration-dependent manner. Apoptotic activity and genotoxic effects were significantly increased, especially with 200 μg/ml concentrations at 48 hours incubation. In conclusion, it was determined that the extract evaluated in this study could be a natural source of antioxidants. Further molecular studies explaining chemo-preventive and chemotherapeutic effects on cancer cells are required to support anticancer efficacy of the plant.