Polyesters from renewable resources: Preparation and characterization

Polyesters were synthesized with monoglycerides prepared from rubber seed oil, a renewable resource. Monoglycerides were obtained by an alcoholysis method from the oil, which was neat or modified by treatments with different amounts of maleic anhydride at 230°C. The polyester resins were subsequently prepared by the condensation polymerization of the monoglycerides with phthalic anhydride. The monoglycerides and resins were characterized by spectroscopic analysis and measurements of the physicochemical properties. The chemical resistance of the polyesters was also studied. The results revealed that the polyesters prepared from the modified monoglycerides possessed better properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3748–3755, 2006     

Processing Effects on Chemical,Functional and Pasting Properties of Cowpea Flour from Different Varieties

Cowpea varieties (IT88D-867-11, IT89KD-288 and MALA) were boiled, roasted, dehulled and later milled into powder. The proximate composition, functional and pasting properties as well as anti-nutritional contents (Tannin) of the product was subsequently determined. The result of the study revealed significant increase (P < 0.05) in the crude protein, crude ash, swelling power and water absorption capacity. Conversely, significant decrease (P < 0.05) was observed in crude fat, starch content, moisture content, solubility and peak viscosity. Boiled samples have significantly higher (P < 0.05) crude protein, swelling power, water absorption capacity, with concomitantly lower solubility and tannin content. Crude ash, moisture, solubility and tannin content of dehulled samples decreased significantly with an increase in protein, swelling power and water absorption capacity. However, IT89KD-288 has the highest protein content irrespective of the processing used. But raw IT89KD-288 showed highest percentage of swelling power, solubility, water absorption capacity and Tannin content. The result revealed that both boiling and dehulling will greatly reduce tannin content of cowpea.     

Evaluation of alumina reinforced oil fly ash composites prepared by spark plasma sintering

The thermomechanical behavior of micro/nano-alumina (Al₂O₃) ceramics reinforced with 1-5 wt.% of acid-treated oil fly ash (OFA) was investigated. Composites were sintered using spark plasma sintering (SPS) technique at a temperature of 1400°C by applying a constant uniaxial pressure of 50 MPa. It was evaluated that the fracture toughness of micro- and nanosized composites improved in contrast with the monolithic alumina. Highest fracture toughness value of 4.85 MPam^1/2 was measured for the nanosized composite reinforced with 5 wt.% OFA. The thermal conductivity of the composites (nano-/microsized) decreased with the increase in temperature. However, the addition of OFA (1-5 wt.%) in nanosized alumina enhanced the thermal conductivity at an evaluated temperature. Furthermore, a minimum thermal expansion value of 6.17 ppm*K⁻¹ was measured for nanosized Al₂O₃/5 wt.% OFA composite. Microstructural characterization of Al₂O₃-OFA composites was done by x-ray diffraction and Raman spectroscopy. Oil fly ash particles were seen to be well dispersed within the alumina matrix. Moreover, the comparative analysis of the nano-/microsized Al₂O₃/OFA composites shows that the mechanical and thermal properties were improved in nanosized alumina composites.     

响应面法优化黄浆水絮凝工艺及其代谢组学分析

为了提高黄浆水的附加值和利用率,缓解排放黄浆水带来的环境污染,本文对黄浆水中的可溶性固形物进行絮凝处理。在单因素实验基础上结合响应面法对黄浆水中可溶性固形物的絮凝工艺进行优化,并且对絮凝前后黄浆水进行了蛋白质和总糖含量测定、生化需氧量和化学需氧量测定以及代谢组学测定。实验结果表明,絮凝沉降黄浆水可溶性固形物最佳工艺参数为:壳聚糖添加量为0.54 mg/mL,海藻酸钠添加量为0.24 mg/mL,pH为4.4,温度为47 ℃,此时黄浆水可溶性固形物沉降率为（46.26%±0.38%）;蛋白质含量下降40.68%、总糖含量下降8.41%;生化需氧量和化学需氧量去除率分别为43%、40.95%。代谢组学实验结果表明:黄浆水絮凝前后有66种化合物含量存在显著变化。本研究结果表明絮凝能有效的降低黄浆水中可溶性固形物的含量,为黄浆水的进一步开发利用提供一定的参考。     

Microbial quality of hemodialysis water,a survey of six centers in Lagos,Nigeria

Patients with end‐stage kidney disease (ESRD) on maintenance hemodialysis (HD) are usually exposed to large volumes of dialysate, which is separated from patients' blood only by thin membrane of dialyzer. It is therefore essential to frequently monitor the quality of HD water to ensure that it meets the recommended standards. The objective of this study was to evaluate the microbial quality of HD water in Lagos, Nigeria. Four sets of pre‐ and post‐treatment water samples, 20 mL each, were collected from six HD centers in Lagos and tested for microbial contamination using the molten Tryptic soy agar in accordance with Association for Advancement of Medical Instrumentation (AAMI) and European Best Practice Guidelines (EBPG). Pyrogen tests were also conducted on pre‐ and post‐treatment samples using standard technique. Information on water treatment modalities, maintenance practices and quality control measures in each center were obtained using a questionnaire. All centers use treated water for HD purpose. None of the HD centers met EBPG/AAMI guidelines for microbial contaminants as the mean levels of Escherichia coli in both feed and treated water were 441.7 ± 87.90 and 168.5 ± 64.03, respectively. E. coli was the commonest organism isolated in both feed and treated water in all the centers. HD water quality is still a neglected problem in our environment and more efforts are required to ensure good water quality for HD purpose.     

Composition and functionality of wheat bran and its application in some cereal food products

Production of wheat bran (WB) for human consumption is estimated to be about 90 million tonnes per year. WB is a cheap and abundant source of dietary fibre which has been linked to improved bowel health and possible prevention of some diseases such as colon cancer. It also contains minerals, vitamins and bioactive compounds such as phenolic acids, arabinoxylans, alkylresorcinol and phytosterols. These compounds have been suggested as an aid in prevention of noncommunicable diseases such as cardiovascular disease. This article discusses WB extraction, its nutritional properties, potential health benefits, effects on quality and sensory properties of some cereal foods, and its application in some baked products as well as in fried cereal snacks, as an additive for oil reduction and fibre enrichment.     

Magnetic hysteresis and domain states in Li1+ substituted Ni–Zn ferrites

Compositions of Ni_0.32Zn_0.68-2xLi_xFe_2+xO₄ with x=0.0, 0.025, 0.050, 0.075, 0.100, 0.125, 0.150, 0.175, 0.200 were prepared by oxalate precursors. The M_s–T curves resemble type R. The magnetic moment (n_B) values were found to increase with increase of Li¹⁺ content up to x=0.175, and thereafter it decreased. The former explained on the basis of the exchange interactions, whereas the decrease of n_B is related to the migration of Ni to tetrahedral (A) sites. There is a decrease in Yafet–Kittle (Y–K) angles at octahedral (B) sites, suggesting that lithium does not favor H_c canting. Actually, Li¹⁺ tends to reduce canting, resulting in the increase of n_B coercive force (H_c) and remanance ratio (R) variations have been related to increase of anisotropy constant (K_l) with increasing Li¹⁺ content. The values of R are comparable with the theoretical value, 0.87, which is probably due to the very high density of the samples. Thermal variations of H_c and R reveal that neither parameter changes rapidly with increasing temperature, indicating that the material contains multi-domain (MD) grains in predominance. These results are also supported by a.c. susceptibility studies. The values of wall susceptibility are higher than those of rotational susceptibility, suggesting that the susceptibility is contributed mainly by the domain wall motion.     

响应面法优化黄浆水超滤工艺及其代谢组学分析

为了高效分离获得蛋白的同时减轻黄浆水的污染问题,提高其综合利用率,本文采用超滤分离技术对黄浆水进行浓缩处理.在单因素实验基础上,采用响应曲面对黄浆水超滤工艺进行优化,并对超滤前后的黄浆水进行了蛋白质和总糖含量测定、生化需氧量(BOD)和化学需氧量(COD)测定以及代谢组学测定.结果表明:黄浆水超滤浓缩工艺的最佳参数为:...     

Effects of pigeon pea and plantain starches on the compressional, mechanical, and disintegration properties of paracetamol tablets

A study has been made of the effects of pigeon pea starch obtained from the plant Cajanus cajan (L) Millisp. (family Fabaceae) and plantain starch obtained from the unripe fruit of Musa paradisiaca L. (family Musaceae) on the compressional, mechanical, and disintegration properties of paracetamol tablets in comparison with official corn starch BP. Analysis of compressional properties was done by using density measurements, and the Heckel and Kawakita equations, whereas the mechanical properties of the tablets were evaluated by using tensile strength (T--a measure of bond strength) and brittle fracture index (BFI--a measure of lamination tendency). The ranking for the mean yield pressure, P(y), for the formulations containing the different starches was generally corn < pigeon pea < plantain starch while the ranking for P(k), an inverse measure of the amount of plasticity, was pigeon pea < plantain < corn starch, which indicated that formulations containing corn starch generally exhibited the fastest onset of plastic deformation, whereas those formulations containing pigeon pea starch exhibited the highest amount of plastic deformation during tableting. The tensile strength of the tablets increased with increase in concentration of the starches while the Brittle Fracture Index decreased. The ranking for T was pigeon pea > plantain > corn starch while the ranking for BFI was corn > plantain > pigeon pea starch. The bonding capacity of the formulations was in general agreement with the tensile strength results. The disintegration time (DT) of the formulation increased with concentration of plantain and corn starches but decreased with concentration of pigeon pea starch. The general ranking of DT values was plantain < pigeon pea < corn starch. Notably, formulations containing pigeon pea starch exhibited the highest bond strength and lowest brittleness, suggesting the usefulness of pigeon pea starch in producing strong tablets with minimal lamination tendency. Plantain starch, on the other hand, would be more useful where faster disintegration of tablet is desired. The results show that the starches could be useful in various formulations depending on the intended use of the tablets with the implication that the experimental starches can be developed for commercial purposes.