Effects of Kenaf Fibre on Fresh Properties of Fibrous Concrete

As a result of global quest for sustainable materials to achieve a bio based economy and low carbon foot print environment, the use of fibre to produce fibrous concrete composite has continuously received significant research attention. While several researches have been conducted on metallic and synthetic fibrous concretes, they exhibit several unavoidable drawbacks and bio fibrous concrete has proven to be a better alternative. Therefore, the effect of fibre volume fraction and fibre length on fresh properties of concrete was investigated. The bio fibrous concrete mix was made of six different fibre volume fractions (0.25%, 0.5%, 0.75%, 1%, 1.5% and 2%) and corresponding three different fibre lengths of 25 mm, 50 mm and 75 mm. A concrete mix proportion of grade 30 N/mm2 at 28 days target strength was prepared. A total of 19 different concrete mixes comprising of one PC mix was the control for the experiment, and 18 different mixes of Kenaf bio fibrous concrete composite (KBFCC) at varying fibre volume fraction (vf) and fibre length (lf) were tested. These mixes were tested for workability (slump, compacting factor and Vebe test) and fresh density. The slump and Vebe time for KBFCCs were 5–100 mm and 3–79 seconds respectively. The slump and Vebe time for PC were 120 mm and 3 seconds respectively. A significant drop from 0.951 to 0.809 for fibre length of 25 mm, 0.947 to 0.799 for fibre length of 50 mm and 0.931 to 0.793 for fibre length of 75 mm was observed for the compacting factor value. Though, KBFCC with fibre content below 1% was workable in spite of its low slump, its high Vebe time and low compacting factor. For fibre volume of 1% and above, the workability of concrete decreased and became very stiff with balling effect. It was seen that fresh density of PC concrete (2358 kg/m3) was higher compared to those of KBFCC (2105-2339 kg/m3), however, both values were lower than 2400 kg/m3 threshold specified by the BS code of practice. The study therefore recommended that fibre contents lesser than 1% and 50 mm length can be used in order to have good fresh properties performance

TRIP-1 via AKT modulation drives lung fibroblast/myofibroblast trans-differentiation

Abstract Background Myofibroblasts are the critical effector cells in the pathogenesis of pulmonary fibrosis which carries a high degree of morbidity and mortality. We have previously identified Type II TGFβ receptor interacting protein 1 (TRIP-1), through proteomic analysis, as a key regulator of collagen contraction in primary human lung fibroblasts—a functional characteristic of myofibroblasts, and the last, but critical step in the process of fibrosis. However, whether or not TRIP-1 modulates fibroblast trans-differentiation to myofibroblasts is not known. Methods TRIP-1 expression was altered in primary human lung fibroblasts by siRNA and plasmid transfection. Transfected fibroblasts were then analyzed for myofibroblast features and function such as α-SMA expression, collagen contraction ability, and resistance to apoptosis. Results The down-regulation of TRIP-1 expression in primary human lung fibroblasts induces α-SMA expression and enhances resistance to apoptosis and collagen contraction ability. In contrast, TRIP-1 over-expression inhibits α-SMA expression. Remarkably, the effects of the loss of TRIP-1 are not abrogated by blockage of TGFβ ligand activation of the Smad3 pathway or by Smad3 knockdown. Rather, a TRIP-1 mediated enhancement of AKT phosphorylation is the implicated pathway. In TRIP-1 knockdown fibroblasts, AKT inhibition prevents α-SMA induction, and transfection with a constitutively active AKT construct drives collagen contraction and decreases apoptosis. Conclusions TRIP-1 regulates fibroblast acquisition of phenotype and function associated with myofibroblasts. The importance of this finding is it suggests TRIP-1 expression could be a potential target in therapeutic strategy aimed against pathological fibrosis.Peer Reviewe

A Study of Factors Influencing Job Satisfaction Among Faculty Members at Selected Historically Black Colleges and Universities in Texas

The purpose of this study was to investigate the level of job satisfaction among full-time faculty members at historically black colleges and universities in Texas with respect to gender, age, marital status, salary, academic rank, level of education, teaching experience, institution of employment, and race/ethnic origin. The investigation was based on the six variables of job satisfaction: work on present job, present pay, supervision, co-workers, promotion, and job in general