A second large plasmid encodes conjugative transfer and antimicrobial resistance in O119:H2 and some typical O111 enteropathogenic \u3ci\u3eEscherichia coli\u3c/i\u3e strains

A novel and functional conjugative transfer system identified in O119:H2 enteropathogenic Escherichia coli (EPEC) strain MB80 by subtractive hybridization is encoded on a large multidrug resistance plasmid, distinct from the well-described EPEC adherence factor (EAF) plasmid. Variants of the MB80 conjugative resistance plasmid were identified in other EPEC strains, including the prototypical O111:NM strain B171, from which the EAF plasmid has been sequenced. This separate large plasmid and the selective advantage that it confers in the antibiotic era have been overlooked because it comigrates with the virulence plasmid on conventional gels

Antibiotic resistance in Escherichia coli from Nigerian students, 1986 1998.

We tested 758 fecal Escherichia coli isolates, recovered from Nigerian students in 1986, 1988, 1990, 1994, and 1998, for susceptibility to seven antimicrobial drugs. The prevalences of strains resistant to tetracycline, ampicillin, chloramphenicol, and streptomycin were 9% to 35% in 1986 and 56% to 100% in 1998. These findings demonstrate that resistance gene reservoirs are increasing in healthy persons

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

A Review of Housing Problems

Housing problems occur both in rich and poor communities across the globe. The objective of this research is to review housing problems which lead to unwholesome environmental conditions. The method used is a review of academic articles, textbooks, internet materials, news articles and publicly available materials on housing problems. Previous authors whose works were reviewed have a convergent view on housing problems including overcrowding and congestion, poor accessibility, substandard and inadequate housing, high cost of building materials, high interest rate and lack of interest by financial institutions to facilitate loans to investors and uncoordinated policies by government. The paper made the following recommendations: (1) government should build low-cost houses to cater for the large number of people who, due to their low-income earnings could not afford a decent apartment; (2) formulation of economic, social and environmental policies that facilitate housing that is both affordable and sustainable by government; (3) improvement of sanitation in poor neighborhoods with poor housing conditions through urban renewal programme