An overview of the formation of calcium phosphate under in vitro environment on the surface of a range of bioactive materials (e.g. from silicate, borate, and phosphate glasses, glass-ceramics, bioceramics to metals) based on recent literature is presented in this review. The mechanism of bone-like calcium phosphate (i.e. hydroxyapatite) formation and the test protocols that are either already in use or currently being investigated for the evaluation of the bioactivity of biomaterials are discussed. This review also highlights the effect of chemical composition and surface charge of materials, types of medium (e.g. simulated body fluid, phosphate-buffered saline and cell culture medium) and test parameters on their bioactivity performance. Finally, a brief summary of the biomedical applications of these newly formed calcium phosphate (either in the form of amorphous or apatite) is presented.

No abstract

The aim of this study was to estimate different body measurements and derive prediction equation for live weight of Jamuna basin sheep using different body measurement. A total of 520 individual records of sheep (47 males and 473 females) including all temporary at nine-month age (320), first pair permanent at 1.6 year age (161) and 2nd pair permanent at two years age (39) were collected from two Upazila of Sherpur district. Body weight (BW) was taken using a weighing scale and different measurements were taken using the tailor's tape measure and measuring stick while animals were on standing position. Data were analyzed with the help of SPSS-v-20 computer package program. Average BW, wither height(WH), rump height(RH), body length(BL), sternum height(SH), body depth(RD), bi-costal diameter(BD), ear length(EL), rump width(RW), head width(HW), rump length(RL), head length(HL), heart girth(HG), cannon bone circumference(CC) and muzzle diameter(MD) were 12.28±2.75 kg, 49.42±3.78, 54.04±3.88, 49.38±4.57, 28.06±3.00, 53.09±4.40, 15.07±2.58, 8.66±3.32, 15.72±2.33, 12.87±2.20, 14.30±2.29, 18.23±2.30, 55.02±4.71, 9.22±1.01, and 16.65±1.73cm, respectively. According to sex BW, WH, RH, SH, RD and CC were found significant (p<0.001), HG and MD were found significant(p<0.01). Stepwise multiple regression analysis according to agein all temporary groups showed that the body weight was found the best fitted equation having the highest R2value 64% (BW = - 15.53+0.24HG+0.13WH+0.16BD-.1RW+0.05EL) whereas in 1.3-1.6 and 1.9-2 years age group the R2 value for BD was 56 (BW = - 15.65+0.31HG+0.22WH)and 83% (BW = -24.51+0.21RH+0.35HG+0. 19BL-0.78RL+1.2RW-0.87HW), respectively. R2value for BD in male (BW = -28.91+0.43HG+0.35WH) and female (BW = -10.62+0.27HG+ 0.13WH+0.06BD-0.13HW+0.07BL-0.10SH-0.10RL) was 88and 59%, respectively. It is concluded that the best prediction parameter of BW was HG, WH, BD, RW, EL, RH, BL and HW. SAARC J. Agri., 18(1): 183-196 (2020)

The rate of decomposition of tert-amyl nitrite (t-AmONO) has been studied in the absence (120"-155°C) and presence (16Oo-190"C) of nitric oxide. In the absence of nitric oxide for low concentrations of tert-amyl nitrite (-10-4M) and small extents of reaction (-l%), the first-order homogeneous rates of acetone formation are a direct measure of reaction (1) since k3a >> kz(N0): BATT, ISLAM, AND RATTRAYMe-2-but-I-ene + HONO ' Me-2-but-2-ene + HONO t-ArnONOThe ratio ks,/kjb was 0.35. Unlike tert-butyl where the rates of the two paths were comparable [(l) and (5)], here the total rate of the elimination process was only 0.5% that of the radical split (1).

This paper reports on the rapid development of porous hydroxyapatite (HA) microspheres with large external pores and fully interconnected porosity.

Jute fabrics-reinforced linear low density polyethylene (LLDPE) matrix composites (50 wt% fiber) were prepared by compression molding and mechanical properties were studied. Polyvinyl chloride (PVC) matrix was incorporated instead of LLDPE in the jute based composites and their mechanical properties were investigated and compared with the control composites. It was found that with the increase of PVC in the LLDPE based composites, the mechanical properties were found to improve significantly. Degradation tests of the composites for upto 24 weeks were performed in soil medium. Water uptake and Thermo-mechanical properties of the composites were also studied.

Jute fabrics (hessian cloth) reinforced polyvinyl chloride (PVC) based composites were prepared by compression molding. Jute content varied from 40-60 wt% in the composites. Four layers of jute fabrics were compression molded with five layers of PVC. It was found that the composite containing 40% jute fabrics showed the best performance. The values of tensile strength (TS), bending strength (BS), tensile modulus (TM), and bending modulus (BM) of the composite (40 wt% jute fabrics) were found to be 59.3 MPa, 62.6 MPa, 1.3 GPa, and 3.2 GPa, respectively. The values of TS and BS were improved to 77% and 46%, respectively, compared to the matrix material PVC. Scanning electron microscopic analysis was carried out to investigate the interfacial properties of the composites. Degradation tests of the composites (up to 6 months) were performed in soil medium and showed partial degradation nature.

Compositionally uniform magnetic Ca2Fe2O5 (srebrodolskite) microspheres created via a rapid, single-stage flame spheroidisation (FS) process using magnetite and carbonate based porogen (1 : 1 Fe3O4 : CaCO3) feedstock powders, are described.