This study is to investigate the capability of producing lignin-based phenol-formaldehyde adhesive (LBPFA) with lignin derived from coir pith collected in the Mekong Delta, Viet Nam. The LBPFA synthetic process underwent non chemical modifications to minimize petrochemicals and energy. Effective factors as reaction time, reaction temperature and various lignin contents of phenol substitution were examined. Physical, chemical and thermal properties containing formaldehyde content, viscosity, solid content, Fourier transformed infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), tensile strength, tensile modulus and tensile strain were conducted. LBPFA was successfully synthesized at various levels of lignin contents substituting for phenol. The LBPFA’s parameters were in accordance with GB/T14372-2006 standard. The optimum reaction time, reaction temperature and lignin replacement content for LBPFA synthesis process were identified at 180 minutes, 900C and 40% wt/wt, respectively. The LBPFA showed the highest dry and wet tensile strengths of 14.42 MPa and 7.66 MPa on wooden boards compared to corresponding figures of commercial resin with 2.98 MPa and 0 MPa, respectively. For plywood, bending strength shown in LBPFA and commercial adhesive were 15.97 MPa and 20.16 MPa, respectively.

Anadara antiquata belongs to the Mollusca phylum, class Bivalvia, distributed in the coastal areas of Vietnam, with high nutritional and economic value. This study focused on the morphological characteristics and genetic diversity of A. antiquata in six regions of central Vietnam (Da Nang, Quang Nam, Phu Yen, Nha Trang, Binh Thuan and Thanh Hoa). The analysis of morphology of A. antiquata had the following results: shell width (SW: 41.45 mm), shell length (SL: 22.54 mm), right shell height (HRV: 29.27 mm), height left sheath (Coach: 28.49 mm), ligament length (LL: 25.74 mm), right trochanteric cavity depth (UHR: 7.90 mm), left trochanteric space depth (UHL: 8, 33 mm), right case symmetry (SRV: 8.58 mm) and left case symmetry (SLV: 8.41 mm). The mean shell volume (SV) and shell cavity volume (DSWT) were 4.45 ml and 11.11 ml, respectively. The average dry peel weight was 11.17 g. Genetic diversity showed that the 8 random primers used to analyze DNA polymorphisms of 41 A. antiquata had 87 amplified polymorphic DNA bands.

Background: Dental caries is a multifactorial and dynamic disease caused by damage to dental hard tissues. It is known as the most common disease of oral health conditions in school-aged children. Caries can affect children’s quality of life, such as studying, recreational activities, and psychosocial well-being. In recent years, some studies done in other provinces of Vietnam reported that the rate of dental caries in primary and permanent dentition was still high. Objectives: To determine the prevalence, indices of dental caries, and oral hygiene status among students from Grade 1 to Grade 5 at Vo Truong Toan elementary school, Ninh Kieu District, Can Tho City in 2021. Materials and methods: A cross-sectional descriptive study was conducted on students from Grade 1 to Grade 5 at Vo Truong Toan elementary school, Ninh Kieu District, Can Tho City in the 2020 – 2021 academic year. Results: A total of 288 students (6 – 11 years of age) participated in this study with the prevalence of caries in all teeth, deciduous dentition, and permanent dentition were 94.8%, 89.9%, and 44.4%, respectively. The overall mean decayed, missing, and filled teeth index was 6.83 ± 3.96, the overall mean decayed, missing, and filled surfaces index was 11.78 ± 10.08, the overall mean significant caries index was 11.35 ± 2.14, and the overall mean untreated caries index was 0.40 ± 1.06. 78.8% of students had good and fair oral hygiene without statistically significant association with gender or age groups (p > 0.05). Conclusions: This study has shown the high prevalence of caries, so the community should carry out preventive solutions to improve correct perceptions and actions.