It is of great importance to develop epoxy vitrimers with the combination of high performance and versatile recyclability. Herein, two imine-containing hardeners were synthesized from bio-based vanillin and petroleum-based p-hydroxy benzaldehyde. The epoxy resins cured by these two hardeners show high T g (>120 °C), tensile strength (>60 MPa), Young's modulus (>2500 MPa), and good solvent resistance. Owing to the incorporation of imine dynamic covalent bond, the cured epoxy resins are reprocessable and degradable. Notably, the chemical degradation products can be reused to prepare new epoxy resins, thus achieving a closed-loop recycling process. Both the reprocessed and chemically recycled epoxy resins exhibit high-percentage retention of thermal and mechanical properties. Finally, this study demonstrates that the epoxy resin cured by the vanillin-based hardener shows comparable thermal, mechanical, and recycling properties compared with the epoxy resin cured by the petroleumbased counterpart.

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The research works was conducted with a view to isolate and identify the Escherichia coli (E. coli) organism from diarrhoeic cases of buffalo reared in selected areas of Bangladesh as well the prevalence and antibiotic sensitivity pattern of the isolated E. coli in the Department of Microbiology and Hygiene, Bangladesh Agricultural University (BAU), Mymensingh-2202 during the period from April 2008 to May 2009. A total of 50 rectal swab samples were collected from 4 different places namely Haluaghat and Boira of Mymensingh, Madupur of Tangail and Kazipur of Sirajgonj districts. The samples were aseptically carried to the laboratory of the Department of Microbiology and Hygiene and subjected to different cultural, morphological and biochemical examinations. Upon cultural, morphological and biochemical examinations 23 (45%) samples were found to be positive for E. coli. The highest prevalence was found in Haluaghat, Mymensingh (53.33%) and the lowest (40.00%) in Boira, Mymensingh and Kazipur, Sirajganj. Antibiogram study revealed that the isolated E. coli was highly sensitive to Enrofloxacin and Ciprofloxacin, moderately sensitive to Cefalexin and Amoxicillin, and resistant to Nalidixic acid and Erythromycin.

Maize (Zea mays L.) is world's third most important cereal crop that has a remarkable productive potential in Bangladesh. In Bangladesh, maize is the second most important cereal crop in terms of production. The selection for high yield with desirable traits depends on the genetic variability in the existing germplasm. Successful breeding programs need adequate genetic variation for selection and improvement based on necessity. The research was conducted in the experimental farm of the

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An experiment was conducted using a randomized complete block design to estimate genetic variability of ten rice genotypes. Analysis of variance for yield and yield contributing traits showed significant (p<0.01) variation among the genotypes. Results of genetic analyses showed a higher phenotypic coefficient of variation compared to their corresponding genotypic coefficient of variation for all the traits measured, which indicates that the traits were influenced by environment. The magnitude of difference between phenotypic coefficient of variance (PCV) and genotypic coefficient of variance (GCV) was less for the traits indicating little influence of environment. The higher estimates of PCV and GCV were observed for number of filled grains panicle -1 (27.53; 26.84), number of unfilled grains panicle -1 (26.76;25.28) and plant height (23.14; 23.00) indicates possibility of genetic improvement through direct selection for these traits, while days to 50% flowering, days to maturity, panicle length, number of effective tillers plant -1 , fertility (%), 1000 Seed weight and yield panicle -1 showed low PCV and GCV values indicating the need for creation of variability by hybridization or mutation followed by selection. High heritability values (>60%) along with high genetic advance and genetic advance as percentage of mean were found for all the traits indicating prevalence of additive gene action, which provides good scope for further improvement by selection.

The development of recyclable thermosets with high performance from renewable resources is highly desirable from the concerns of environmental and resource economics. Here, a full biobased carboxyl-containing epoxy hardener (CF-quercetin) was prepared from quercetin and succinic anhydride (starch/sugar derivative) through a mild one-step reaction. The epoxy resin cured by CFquercetin shows tensile strength (92 MPa) comparable with commercial counterparts and high storage modulus (3800 MPa) at room temperature. Owing to the high content of dynamic ester bonds in the epoxy networks, the cured epoxy resin can be repeatedly reprocessed like thermoplastics, and 91% recovery of tensile strength from the first reprocessing cycle can be achieved. Meanwhile, the glass-transition temperature and thermal stability of the reprocessed epoxy resin remain almost constant compared with the original epoxy resin. Furthermore, the epoxy resin cured by CF-quercetin presents rapid degradation in alkali aqueous solution (NaOH, 1 M) within 6 h at room temperature, but it is fully nondegradable in acidic and neutral solutions over a period of 120 days. The cured epoxy resin also shows acceptable stability in many conventional organic solvents. Taken together, our work provides a simple method to prepare a universal quercetin-based hardener for epoxy resins with reprocessability, degradability, and high mechanical performance.