Aspects of Garcina kola Toxicity to a Wild Strain of Saccharomyces cerevisiae from a Brewery Environment

Bitter cola (Garcinia kola) powder and its ethanolic extract were assessed for their ability to inhibit the growth of a wild strain of Saccharomyces cerevisiae isolated from a brewery environment. The iso-alpha acid contents of the G. kola powder, G. kola extract and hop extract were determined as 5.85 mg/l, 6.34 mg/l and 7.65 mg/l, respectively, showing that the iso-alpha acid contents of G. kola extract and G. kola powder compared relatively well with that of hop extract. The antimicrobial activity of both agents, using Humulus lupulus ethanolic extract as control, showed a high dependence on the temperature of assay. At most of the temperatures evaluated (30 – 45 oC), the rates of antimicrobial activity differed. Garcinia kola ethanolic extract and hops extract displayed total inhibition of the wild yeast growth at temperature of 40 oC at concentrations of about 0.039 mg/ml and 0.078 mg/ml respectively. Humulus lupulus extract (hops) had the highest generation time at 450C at a concentration of 0.078 mg/ml. The complete inhibition of the yeast growth by G. kola extract at 40 oC indicated that it had higher antimicrobial activity against this yeast than hops extract. In all the temperatures evaluated both G. kola ethanolic extract and powder compared favourably with hops extract with respect to antimicrobial activity against a wild strain of Saccharomyces cerevisiae at various concentrations. These results revealed that the antimicrobial activity of these hopping agents were temperature and concentration dependent

Application of High-Voltage, Precision, Low-Power Max9943/Max9944 Operational Amplifier in Industrial Process Control Using ±20ma OR 4-20ma Current-Loop Systems

This article explains how to apply a high-voltage, high-current-drive operational amplifier to convert a voltage signal into a ±20mA or 4–20mA current signal for use in process-control industrial applications. The MAX9943 op amp a family of high-voltage amplifiers that offers precision, low drift, and low power consumption device was used as case study]. Experiments are described and test results presented. Current loops are known for their high immune to noise compare to voltage-modulated signals, a feature that makes it ideal for use in a noisy industrial environment. This signal can travel over a long distance, sending or receiving information from remote locations. A current loop typically includes a sensor, transmitter, receiver, and an ADC or a micro-controller (figure 1). The sensor measures a physical parameters such as pressure or temperature and provides a corresponding output voltage. The transmitter converts the sensor's output into a proportional 4mA-to-20mA current signal, while the receiver then converts the 4mA-to-20mA current into a voltage signal output. This receiver's output is then received, interpreted and converts into a digital signal output by an ADC or a micro-controller. Experiment performed using the relationship the relationship stated in equation 5, shows that if the input voltage level rise above or fall below ±2.5v, the op amp device attains its saturation point and its output voltage can no longer increase. As shown in figure 3, where the curve flatten and no longer follow the ideal linearity characteristics that was supposed

Analysis of Electrical Porcelain Insulators from Local Clays

This paper focused on the chemical analysis of electrical porcelain insulators based on local clays. Test samples were made by conducting some chemical composition test using the Atomic Assumption Spectrophotometer (AAS). The clay samples were also tested for linear shrinkage and apparent porosity. Based on the results obtained, the linear shrinkage values recorded range from 7.29% to 14.29% for Iva Valley formulations, 5.14% to 14.71% for Nawfija and 7.74% to 10.29% for Ekwulobia. It was observed that linear shrinkage decreases as the content of non-plastic materials increases and increases as clay content increases. Iva Valley formulation recorded porosity values ranging from 8.84% to 20.80%. For Nawfija formulation, porosity values range from 10.81% to 17.30% while Ekwulobia formulations gave porosity values ranging from 9.52% to 16.82. Porcelain insulators that constitute the above results were found to have requisite properties that make them suitable for domestic production of porcelains insulators from the clay samples studied

Pterodactyl: Trade Study for an Integrated Control System Design of a Mechanically Deployable Entry Vehicle

This paper presents the trade study method used to evaluate and downselect from a set of guidance and control (G&C) system designs for a mechanically Deployable Entry Vehicle (DEV). The Pterodactyl project was prompted by the challenge to develop an effective G&C system for a vehicle without a backshell, which is the case for DEVs. For the DEV, the project assumed a specific aeroshell geometry pertaining to an Adaptable, Deployable Entry and Placement Technology (ADEPT) vehicle, which was successfully developed by NASAs Space Technology Mission Directorate (STMD) prior to this study. The Pterodactyl project designed three different entry G&C systems for precision targeting. This paper details the Figures of Merit (FOMs) and metrics used during the course of the projects G&C system assessment. The relative importance of the FOMs was determined from the Analytic Hierarchy Process (AHP), which was used to develop weights that were combined with quantitative design metrics and engineering judgement to rank the G&C systems against one another. This systematic method takes into consideration the projects input while simultaneously reducing unintentional judgement bias and ultimately was used to select a single G&C design for the project to pursue in the next design phase

Customizable Ceramic Nanocomposites Using Carbon Nanotubes

A novel tweakable nanocomposite was prepared by spark plasma sintering followed by systematic oxidation of carbon nanotube (CNT) molecules to produce alumina/carbon nanotube nanocomposites with surface porosities. The mechanical properties (flexural strength and fracture toughness), surface area, and electrical conductivities were characterized and compared. The nanocomposites were extensively analyzed by field emission scanning electron microscopy (FE-SEM) for 2D qualitative surface morphological analysis. Adding CNTs in ceramic matrices and then systematically oxidizing them, without substantial reduction in densification, induces significant capability to achieve desirable/application oriented balance between mechanical, electrical, and catalytic properties of these ceramic nanocomposites. This novel strategy, upon further development, opens new level of opportunities for real-world/industrial applications of these relatively novel engineering materials

Pterodactyl: Trade Study for an Integrated Control System Design of a Mechanically Deployed Entry Vehicle

This paper presents a trade study method used to evaluate and down-select from a set of guidance and control (G&C) system designs for a mechanically deployable entry vehicle (DEV). The Pterodactyl project, funded by NASA's Space Technology Mission Directorate (STMD), was prompted by the challenge to develop an effective G&C system for a vehicle without a backshell, which is the case for DEVs. For the DEV, the project assumed a specific aeroshell geometry pertaining to an Adaptable, Deployable, Entry Placement Technology (ADEPT) vehicle, which was successfully developed by STMD prior to this study. The Pterodactyl project designed three different G&C systems for the vehicle's precise entry, which this paper briefly discusses. This paper details the Figures of Merit (FOMs) and metrics used during the course of the project's G&C system assessment. Each G&C configuration was traded against the three FOMs categories: G&C system performance, affordability and life cycle costs, and safety and mission success. The relative importance of the FOMs was determined from the Analytical Hierarchy Process (AHP), which was used to develop weights that were combined with quantitative design metrics and engineering judgement to rank the G&C systems against one another. This systematic method takes into consideration the project's input while simultaneously reducing unintentional judgement bias and ultimately was used to select a single G&C design for the project to continue pursuing in the next prototyping and testing phase

Benefits and pitfalls of multimedia and interactive features in technology-enhanced storybooks:A meta-analysis

A meta-analysis was conducted on the effects of technology-enhanced stories for young children’s literacy development when compared to listening to stories in more traditional settings like storybook reading. A small but significant additional benefit of technology was found for story comprehension (g+ = 0.17) and expressive vocabulary (g+ = 0.20), based on data from 2,147 children in 43 studies. When investigating the different characteristics of technology-enhanced stories, multimedia features like animated pictures, music, and sound effects were found beneficial. In contrast, interactive elements like hotspots, games, and dictionaries were found to be distracting. Especially for children disadvantaged because of less stimulating family environments, multimedia features were helpful and interactive features were detrimental. Findings are discussed from the perspective of cognitive processing theories

Congenital Plasmodium falciparum infection in neonates in Muheza District, Tanzania

BACKGROUND\ud \ud Although recent reports on congenital malaria suggest that the incidence is increasing, it is difficult to determine whether the clinical disease is due to parasites acquired before delivery or as a result of contamination by maternal blood at birth. Understanding of the method of parasite acquisition is important for estimating the time incidence of congenital malaria and design of preventive measures. The aim of this study was to determine whether the first Plasmodium falciparum malaria disease in infants is due to same parasites present on the placenta at birth.\ud \ud METHODS\ud \ud Babies born to mothers with P. falciparum parasites on the placenta detected by PCR were followed up to two years and observed for malaria episodes. Paired placental and infant peripheral blood samples at first malaria episode within first three months of life were genotyped (msp2) to determine genetic relatedness. Selected amplifications from nested PCR were sequenced and compared between pairs.\ud \ud RESULTS\ud \ud Eighteen (19.1%) out of 95 infants who were followed up developed clinical malaria within the first three months of age. Eight pairs (60%) out of 14 pairs of sequenced placental and cord samples were genetically related while six (40%) were genetically unrelated. One pair (14.3%) out of seven pairs of sequenced placental and infants samples were genetically related. In addition, infants born from primigravidae mothers were more likely to be infected with P. falciparum (P < 0.001) as compared to infants from secundigravidae and multigravidae mothers during the two years of follow up. Infants from multigravidae mothers got the first P. falciparum infection earlier than those from secundigravidae and primigravidae mothers (RR = 1.43).\ud \ud CONCLUSION\ud \ud Plasmodium falciparum malaria parasites present on the placenta as detected by PCR are more likely to result in clinical disease (congenital malaria) in the infant during the first three months of life. However, sequencing data seem to question the validity of this likelihood. Therefore, the relationship between placental parasites and first clinical disease need to be confirmed in larger studies

The burden, distribution and risk factors for cervical oncogenic human papilloma virus infection in HIV positive Nigerian women

Background: The expected reduction in cervical cancer incidence as a result of increased access to antiretroviral therapy is yet to be seen. In this study we investigated the effect of HIV infection and treatment on high-risk (hr) human papilloma virus (HPV) prevalence and distribution. Methods: Cervical cells from 515 (220 HIV positive and 295 HIV negative) women, recruited during community cervical cancer screening programme in states of Ogun and Lagos and at the cervical cancer screen clinic, Nigerian Institute of Medical Research Lagos were evaluated for the presence of 13 hr HPV genotypes by polymerase chain reaction based assay. Results: The prevalence of high-risk HPV was 19.6% in the studied population. HPV 16 (3.9%), 35 (3.5%), 58 (3.3%) and 31 (3.3%) were the most common hr HPV infections detected. We observed that the prevalence of hr HPV was higher in HIV positives (24.5%) than 15.9% in HIV negative women (OR = 1.7; 95% CI: 1.1-2.7). A multivariate logistic regression analysis showed a lower hr HPV prevalence in HIV positive women on antiretroviral drugs (OR = 0.4; 95% CI: 0.3-0.5) and with CD4 count of 500 and above (OR = 0.7; 95% CI: 0.5-0.8). A higher prevalence of hr HPV was also noted in HIV positive women with CD4 count <200 cells/mm3 (OR = 2.4; 95% CI: 1.7-5.9). Conclusion: HPV 16, 35, 58 and 31 genotypes were the most common hr HPV infection in our study group, which could be regarded as high risk general population sample; with higher prevalence of HPV 16 and 35 in HIV positive women than in HIV negative women. The use of antiretroviral drugs was found to be associated with a lower prevalence of hr HPV infection, compared to those not on treatment. This study raises important issues that should be further investigated to enable the development of robust cervical cancer prevention and control strategies for women in our setting

Pentanol isomer synthesis in engineered microorganisms

Pentanol isomers such as 2-methyl-1-butanol and 3-methyl-1-butanol are a useful class of chemicals with a potential application as biofuels. They are found as natural by-products of microbial fermentations from amino acid substrates. However, the production titer and yield of the natural processes are too low to be considered for practical applications. Through metabolic engineering, microbial strains for the production of these isomers have been developed, as well as that for 1-pentanol and pentenol. Although the current production levels are still too low for immediate industrial applications, the approach holds significant promise for major breakthroughs in production efficiency