Optimization of Enzymatic Hydrolysis of Manihot esculenta Root Starch by Alpha-Amylase and Glucoamylase Using Response Surface Methodology

Cassava starch hydrolysis was investigated in this study using alpha amylase and glucoamylase. The effects of process variables, namely: temperature, pH and time were studied and optimized for hydrolysis of cassava (Manihot esculenta) flour to glucose syrup. Three levels of process variables were used for the study. The three levels of process variables were: temperature (60, 67 and 74 oC), time (1.5, 2.0 and 2.5 h) and pH (4.5, 5 and 5.5). A polynomial regression model was developed using the experimental data. The results showed that production of reducing sugar was strongly affected by the variation of variables on alpha amylase and glucoamylase hydrolysis of cassava starch. The fit of the model was expressed by the coefficient of determination R2 which was found to be 0.948 indicating that 94.8 % of the variability in the response can be explained by the model. The value also indicates that only 5.2 % of the total variation is not explained by the model. This shows that equation (2) is a suitable model to describe the response of the experiment pertaining to reducing sugar production. The statistical significance of the model was validated by F-test for analysis of variance (p ? 0.05). For alpha amylase and glucoamylase hydrolysis, the optimum value of temperature, time and pH were found to be 74 oC, pH 5.5 and time 1.5 h. The maximum reducing sugar production at optimum condition was 257 g/l representing 73.43 % conversion or 73.43 dextrose equivalent (DE). Key words: cassava starch, hydrolysis, factorial design, glucose syrup, dextrose equivalent

ENERGY AND EXERGY ANALYSES OF A 220MW STEAM POWER PLANT

This study presents a thermodynamic analysis of a 220MW thermal plant using its design and operating data. The plant was simulated using HYSYS version 3.2 simulator software. The whole plant was sectionalised into three, each comprising of different units to determine the contribution of each unit to the efficiency and irreversibility of the plant. The maximum exergy loss of 168MW was in the boiler unit. The energetic and exergetic efficiencies were studied for different parameters such as turbine inlet temperature and pressure and fuel flow rate. The overall efficiency of the plant in terms of the first law of thermodynamics (energetic) was 24.1% and the second law analysis (exergetic) was 23.3%

Obstetric analgesia for vaginal birth in contemporary obstetrics: a survey of the practice of obstetricians in Nigeria

BACKGROUND: Contemporary obstetrics in sub-Saharan Africa is yet to meet the analgesic needs of most women during child birth for a satisfactory birth experience and expectedly, obstetricians have a major role to play in achieving this. METHODS: This was a questionnaire-based, cross-sectional study of 151 obstetricians and gynecologists that attended the 46th Annual General Meeting and Scientific Conference of the Society of Gynaecology and Obstetrics of Nigeria (SOGON) held in Abakaliki, southeast Nigeria in November, 2012. SOGON is the umbrella body that oversees the obstetric and gynecological practice in Nigeria. Data was collated and analyzed with Epi-info statistical software, and conclusions were drawn by means of simple percentages and inferential statistics using Odds Ratio, with P-value < 0.05 at 95% Confidence Interval (CI) taken to be statistically significant. RESULTS: Of the 151 participants, males predominated; 110 (72.9%) practiced in government-owned tertiary hospitals in urban locations. Only 74 (49%) offered obstetric analgesia. Among users, only 20 (13.3%) offered obstetric analgesia routinely to parturients, 44 (29.1%) sometimes and 10 (6.6%) on patients’ requests. The commonest analgesia was opioids (41.1%). Among non-users, the commonest reasons adduced were fear of respiratory distress (31.1%), cost (24.7%) and late presentation in labour (15.6%). CONCLUSION: The routine prescription and utilization of obstetric analgesia by obstetricians in Nigeria is still low. Obstetricians are encouraged to step up its use to make childbirth a more fulfilling experience for parturients

Permanence, Temporality and the Rhythms of Life : Exploring Significance of the Village Arena in Igbo Culture

The village arena (or ‘square’ or ‘Otobo’ in Nsukka Igbo) is at the physical and socio-cultural centre of Igbo life, in southeast Nigeria. It is a space where intangible Igbo cultural heritage is played out, and also serves as a virtual museum where heritage materials are kept. The arena performs its roles in two very different ways: as a sacred space hosting initiation rites and religious rituals; and as a profane space for meetings and ceremonies. Either way, these uses see the arena transition between permanency and temporality, following routines and rhythms which themselves give the practices meaning and significance, and contribute to their inscription on the landscape. This paper explores the complexities associated with these village arenas with a particular focus on their socio-cultural, political, economic and religious functions through time, as well as the way those complexities are manifest in material cultures that serve to characterize the village arena

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

EXPERIMENTAL DESIGN AND DEVELOPMENT OF LOCALLY MADE PARABOLIC TROUGH SOLAR THERMAL COLLECTOR UNIT

The design and analysis of Parabolic Trough Solar Thermal Collector (PTSTC) system used to generate hot/steam water for domestic and industrial purposes were carried out. The parametric studies were also conducted on the collector, study the effectiveness of hot water production for potential applications. The PTSC was designed with Parabolic Software version 2.0. The fabrication and design were done with a combination of reflector surface, reflector support, absorber pipe and wooden stand. The absorber pipe was painted in black colour while the trough was manually operated. The flow of water in the system follows the recycling process repeated during data acquisition. The ambient temperature, the inlet and outlet temperature of the receiver and total solar radiation on the PTSC were recorded. Different flow rate of the Heat Transfer Fluid (HTF) was tested at 0.021, 0.022, 0.023 and 0.024 kg/s respectively. Collected data showed the maximum outlet water temperature attained as 72oC. The average outlet temperature increased from 36oC at 10:30 hour to 69.84oC at 16:00 hour. The average beam radiation during the collection period was 699 W/m2. Different flow rates show that the lower the flow rate, the higher the efficiency of the system. The study revealed that the developed parabolic trough solar collector is viable for the production of sterilized water and low stage steam for domestic and industrial purposes