Catalytic cracking of palm oil for the production of biofuels: optimization studies

Oil palm is widely grown in Malaysia. Palm oil has attracted the attention of researchers to develop an 'environmentally friendly' and high quality fuel, free of nitrogen and sulfur. In the present study, the catalytic cracking of palm oil to biofuel was studied over REY catalyst in a transport riser reactor at atmospheric pressure. The effect of reaction temperature (400-500 degrees C), catalyst/palm oil ratio (5-10) and residence time (10-30s) was studied over the yield of bio-gasoline and gas as fuel. Design of experiments was used to study the effect of operating variables over conversion of palm oil and yield of hydrocarbon fuel. The response surface methodology was used to determine the optimum value of the operating variables for maximum yield of bio-gasoline fraction in the liquid product obtained.     

Characterisation of Ercc1 deficiency in the liver and in conditional Ercc1-deficient primary hepatocytes in vitro

The ERCC1/XPF complex is responsible for incision at the 5' side of the lesion during nucleotide excision repair and is also involved in homologous recombination and interstrand cross-link repair. The aim of the current study was to set up a better model for examination of Ercc1 deficiency in the murine liver and to determine the DNA lesions responsible for the premature polyploidy observed. We used the Cre/lox system with an adenovirus carrying Cre recombinase to conditionally induce Ercc1 deficiency in murine hepatocytes in vitro. Increased levels of apoptosis were apparent in our Ercc1-deficient cultures, both spontaneously and after UV irradiation and oxidative DNA damage. Increased apoptosis was also observed in simple Ercc1-deficient livers and the time course of the development of polyploidy was characterised. Livers from simple Ercc1 knockout mice contained mitochondria with disrupted outer membranes. Lipid accumulation was observed in older Ercc1-deficient hepatocyte cultures and in young Ercc1-deficient and wild-type livers. Lipids disappeared from the wild-type livers with age, but persisted in Ercc1-deficient livers, suggesting that a reduced ability to repair oxidative DNA damage and a malfunction of oxidative pathways could be responsible for the Ercc1-deficient liver phenotype. Real-time RT-PCR was used to determine differences in expression of cell cycle regulation and survival genes between Ercc1-deficient and control livers. Higher mRNA levels of Igfbp2, a possible marker for polyploidy, and p21 were detected in Ercc1-deficient livers. The pro-apoptotic factor, Bax, showed increased levels of mRNA expression in young Ercc1-deficient livers. However, no elevation in the levels of reactive oxygen species, or of malondialdehyde DNA adducts, a product of oxidative DNA damage, were found in Ercc1-deficient liver and no elevated levels of genes involved in the oxidative damage response were seen.     

Histochemical localization of enzymes in the stigma and style of Gossypium hirsutum L. during pre- and post-pollination stages.

The distributional pattern of some enzymes (esterase, beta-D-galactosidase, succinate dehydrogenase and malate dehydrogenase) is described in the dry stigma and closed style of Gossypium Hirsutum L. during pre- and post-pollination stages. All the four enzymes indicated granular reaction and increased activity in the transmitting tissue and its surrounding cells during post pollinated stage. The possible physiological role of these enzymes in pollen tube growth in vivo in stigma and style is discussed.     

Establishment of a rat placental cell line expressing characteristics of extraembryonic membranes

A cell line was derived from midgestation chorioallantoic placental explants of the outbred Holtzman rat. The cell line was found to express characteristics of extraembryonic membranes and to grow when introduced into allogeneic hosts. Growth in allogeneic hosts was detected following intraperitoneal injection of the cells but not following subcutaneous injection. The transplanted cells grew as cystic structures free in the peritoneum and as solid masses adhered to various abdominal organs. Cystic structures had a homogeneous morphology consisting of an epithelial-like cell layer surrounding a fluid-filled sac. Solid masses had a heterogeneous morphology, containing parts resembling normal components of the extraembryonic membranes (trophoblast, parietal, and visceral yolk sacs). Biochemical analysis of the placenta-derived cell line and transplanted structures derived from the cell line indicated that the cells had the potential to produce a variety of proteins characteristic of extraembryonic tissues. Cultured cells and both types of in vivo transplants produced the basement membrane protein, laminin. Peritoneal cystic structures also contained alpha-fetoprotein mRNA and very high levels of c-fos mRNA. Solid masses demonstrated elevated alkaline phosphatase activity, a marker of trophoblast cells. Cells grown in vitro expressed elevated c-myc mRNA levels, whereas, c-myc mRNA levels were reduced in the in vivo transplants. The behavior of the cell line in vitro and following in vivo transplantation suggests it contains elements capable of differentiation toward various components of the extraembryonic membranes. The results indicate that the rat placental cell line will be valuable for future studies on the differentiation of trophoblast cells and other components of the extraembryonic membranes.     

Prediction of body volume by a stepwise linear regression technique

Body volume and 35 anthropometric measurements were obtained from 88 active soldiers using standard techniques. These anthropometric measurements were examined for their possible relationships to body volume using stepwise linear regression analysis. Four measurements (Body weight, anterior thigh skinfold thickness, subscapular skinfold thickness and suprailiac skinfold thickness) accounted for 99.7% of the variation in body volume and the introduction of each of these measurements in the equation was significant. The regression equation for predicting body volume from these 4 anthropometric measurements had a multiple correlation coefficient of 0.9987 (P less than 0.001). Body weight alone was correlated with body volume to the extent of 0.9966. An attempt has therefore been made to develop a multiple linear regression equation without incorporation of body weight in the regression analysis. Nine measurements were selected by stepwise linear regression analysis for predicting body volume. These nine measurements accounted for 97.1% of the variation in body volume. These equations have been validated on another small sample of 22 soldiers. The analysis has also revealed that a direct regression of body density from the anthropometric variables gives more accurate results than when estimated body volumes are utilized for calculating body density.     

Guaianolides from Centaurea canariensis

The aerial parts of Centaurea canariensis afforded four new guaianolides, all closely related to dehydrocostus lactone, and a derivative of costic acid. The structures were elucidated by spectroscopic methods.     

Regulation of protein synthesis in rabbit reticulocyte lysates: effect of of Ca2+, Mg2+, and Mn2+ on self-phosphorylation and heterophosphorylation catalyzed by the heme-regulated and double-stranded-RNA-activated protein kinases

The influence of divalent cations Mg²⁺, Mn²⁺, and Ca²⁺ on the cyclic-AMP-independent protein kinases of the heine-regulated and double-stranded-RNA-activated translational inhibitory protein kinases on self-phosphorylation and heterophosphorylation of the substrate (the 38 000-dalton subunit of initiation factor eIF-2) has been examined, Results show that Mg²⁺, Mn²⁺, and Ca²⁺ affect the activities of these enzymes in the following fashion. Mg²⁺ supports both self-phosphorylation and heterophosphorylation efficiently. Mn²⁺ on the other hand supports self-phosphorylation but to a lesser degree the heterophosphorylation, Ca²⁺ promotes neither self-phosphorylation nor hetero-phosphorylation.