Selectively Permeable Microbial Nanoculture System as Artificial Microniches

Microfluidics-based approaches for isolating microbes, replicating their microenvironments and growth conditions can provide new platforms to elucidate many fundamental biological questions. For instance, the spatial confinement of microorganisms in microcompartments can spawn new insights on the inherent advantages of cell clustering and biofilm formation in microbial survival and virulence mechanisms. As the worldwide antibiotic crisis persists, there is an urgent need for emerging technologies that enable the scrutiny of the evolution of multidrug resistance, and facilitate the study of cooperative or antagonistic microbial interactions. Here we describe a method to generate artificial multifunctional microniches in order to encapsulate and interrogate microbes. Using a flow-focusing microfluidic device, microorganisms including Pseudomonas aeruginosa and Escherichia coli (Gram-negative bacteria), Streptococcus mutans (Gram-positive bacterium) and Candida albicans (fungus) were grown in a polydimethylsiloxane (PDMS)-based nanoculture system. The selective permeability of the nanocultures to small molecules including antibiotics, signaling molecules and fluorescent dyes allows assessing essential cell functionalities (e.g. growth kinetics, cell vitality, pH change), as well as characterize inter-species or inter-kingdom interactions, and microbial dynamics in response to antibiotic attacks. The multifunctional nanoculture system has broad potential for studying microbiome dynamics, and identifying new bioactive molecules such as antimicrobials from these defined microcosms

Achieving polio eradication in Nigeria: Prospects and challenges

The Global polio eradication initiative was launched in 1988 by the international community. Since then, tremendous progress has been made (99%). However, the last 1% of the journey has experienced several setbacks and rate of progress has slowed down in the last few years. Nigeria is one of the remaining 3 endemic countries in the world that has never interrupted the transmission of the poliovirus compared to more than 125 countries in 1988.What are the prospects and challenges to polio eradication in Nigeria?This paper discusses these and other relevant issues regarding polioeradication in Nigeria

A general computer-based methodology for work injury analysis in a production assembly line

Repetitive injuries have been a major obstacle in production assembly lines all over the world. These injuries have greatly reduced the production efficiency of assembly plants and also negatively affected human health. Various attempts have been made by the Canadian government through the Worker’s Compensation Board (WCB) to prevent the occurrences of these injuries because of the associated cost and effects. These attempts failed as the cost of injuries acquired in the workplace continues to increase. For example, in New Zealand alone, the total cost of accidents in 2005, is estimated at $300 million (Accident Compensation Corporation, 2005). In Canada, the number of accepted claims alone amount to 15623 people (Workers Compensation Board of Canada, 2003).A human body can be viewed as a mechanism that is composed of links and joints controlled by a central nervous system and are subject to stress, strain, fatigue and failure as can be observed on a regular industrial robot. But unlike the robot which is designed proactively, these stress and strain factors could be because of certain conditions such as inappropriate work posture, poor assembly line design, excessive workload, and poor work conditions. Often, it is almost uncertain to make a conceptual assessment of the appropriate ergonomic design of a production system before the assembly line is built and put in use. This research will propose a general computer-based methodology for analysis of work injuries given an assembly line where human workers perform repetitive operations. The general methodology integrates sophisticated computer software systems for biomechanics simulation with various manual measurement techniques and methods. The research further proposed a simple and handy synthesis method with which problematic areas of assembly line design, with special reference to human work design can be identified and improved. The proposed methodology for analysis and synthesis is then implemented in a real assembly line to understand the effects of different work activities on the human body. Various software packages and motion tracking techniques will be considered prior to the actual implementation of the final methodology. A rule of thumb table will also be presented as a guideline for the re-design process. The research also proposed a general procedure and specific formula within a specific regional context to calculate the costs of worker injuries in real-life assembly system. This formula thus allows us to obtain the total cost of injuries in a production assembly line, making it possible to optimize the design and operation of the assembly line

Electrochemical Control of Bacterial Persister Cells

The emergence of antibiotic-resistant bacteria has presented an increasing challenge to infection control. Conventional methods of antibacterial treatment involving high dose of antibiotics or surgical intervention have proven insufficient for eradicating persistent infections, such as those associated with medical implants. It is well recognized that bacterial populations commonly contain a small percentage of phenotypic variants, known as persister cells, which are metabolically inactive and extremely tolerant to antibiotics. When the antibiotic treatment is stopped, surviving persister cells can regenerate the bacterial population with a similar percentage of persister cells. Thus, persistence presents a great challenge to curing chronic infections. In this study, we introduced a novel method for controlling bacterial persistence based on a phenomenon we named electrochemical control of persister cells (ECCP). We demonstrate that bacterial persister cells can be effectively eliminated by low-level direct currents (DCs); e.g. treatment with 70 μA/cm2 DC for 1 h using stainless steel (SS) 304 reduced the number of viable planktonic persister cells of Pseudomonas aeruginosa PAO1 by 98% compared to the untreated control. In addition to persister killing by applying DC alone, synergistic effects were observed when treating persister cells with 70 μA/cm2 DC and 1.5 μg/mL tobramycin together using SS 304 electrodes. The same level of DC was also found to be cidal to biofilm associated persister cells of P. aeruginosa PAO1. Based on this discovery, the electrophysiological properties of P. aeruginosa PAO1 cells treated with 70 μA/cm2 DC using carbon and SS 304 electrodes were characterized both at the cellular and genetic levels to understand the mechanism of ECCP. We found that DC treatments affected surface charge and membrane integrity of P. aeruginosa, leading to increase intracellular concentration of metal cations as observed via scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analysis. Moreover, electrochemical treatments mediated via carbon electrodes provoked the permeabilization of the cells to extracellular materials, and increased their susceptibility to antibiotics, which led to complete eradication of the persisters. These findings are corroborated by DNA microarray analysis, which revealed that DC treatments have profound effects on the physiology of persister cells, altering the regulation of genes involved in antibiotic resistance, pyocin-related functions, and SOS response. Comparative transmission electron microscopy (TEM) studies of the stationary phase P. aeruginosa PAO1 cells confirmed that DC treatments resulted in the compartmentalization of intracellular contents, release of outer membrane vesicles, or cell lysis. To design novel systems to effectively control infections associated with biofilms and persister cells, the safety and the efficacy of ECCP were evaluated in co-culture models with human epithelial cells and P. aeruginosa PAO1. In addition, a pilot animal study was conducted to investigate the effects of electrochemical currents using a rabbit model of sinus infections. P. aeruginosa PAO1 was used to induce rhinosinusitis in rabbits, which were then treated with antibiotics, or antibiotics with electrical current, and compared with the untreated controls. The results of this study validated the effectiveness of electrochemical treatment in reducing both biofilms and planktonic cells in vivo. Overall, these findings improved the understanding of the electrophysiology of bacterial persister cells, and provided new insight for designing novel systems to effectively control infections associated with biofilms and persister cells

Challenges of Managing Childhood Malaria in a Developing Country: The Case of Nigeria

Malaria still remains one of the highest childhood killer diseases, especially in the developing countries of Africa, Southeast Asia, and Eastern Mediterranean regions. With an estimated 100 million cases and 300,000 deaths from malaria annually, Nigeria has one of the highest burdens of malaria in the world, with children mostly affected. It accounts for 60% of outpatient visits, 30% hospitalization among children under 5 years of age. Great efforts and huge funding have been committed globally towards the fight for malaria, but malaria continues to be a major challenge in these developing countries, especially countries in Sub-Saharan Africa. The World Health Organisation adopted a cost-effective intervention strategy, which comprises a three-pronged approach: vector control, chemoprophylaxis, and case management. Case management involves early diagnosis and treatment. This chapter looks at the challenges militating against the achievement of this important aspect of malaria control in children as well as efforts that have been made or not made to overcome these challenges using Nigeria as a case study

Mothers’ knowledge, perception and practice of childhood immunization in Enugu

Introduction: Immunization has been shown to be the most successful and cost-effective public health intervention in the 20th century. In the developing world, it does not only prevent about three million child deaths annually, but also has the potential to prevent additional two million deaths if coverage improves. However, immunization coverage has remained low in Nigeria although vaccines are provided relatively free by the government. Efforts have focused on the health worker, health system and logistics with little attention being paid to maternal factors like knowledge, perception, beliefs and practice.Objectives: To assess mothers’ knowledge, perception and practice of routine and campaign immunization in Enugu.Methods: A structured questionnaire was administered to 207 mothers who have at least one child less than 5 years of age, attending children outpatient and immunization clinics at the University of Nigeria Teaching Hospital, Enugu.Results: Forty-eight per cent of the mothers had tertiary education, 42% had secondary education, and 9% had primary education while 1% had no formal education. Eighty-two per cent knew that children are immunized to prevent major killer diseases, 14% and 3.4% believed it was to prevent all diseases, and to treat diseases respectively. Most mothers took their children to health facilities for routine immunization (95.2%) and also accepted immunization on immunization campaign days (75.4%). However, 23.6% had never immunized their children during campaigns. On the other hand, 13% (27) of mothers had out-rightly rejected immunization during campaign while 85% (177) had never rejected immunization. The remaining 2% were not immunized due to reasons other than rejection. More mothers significantly rejected campaign immunization than the number that did not go for routine immunization (p=0.000). Maternal highest educational level was significantly associated with knowledge of reason for immunization and acceptance of immunization (p=0.000). Religious denomination was not significantly associated with rejection of campaign immunization (p=0.056).Conclusion: Most mothers studied had good knowledge and positive perception and practice of immunization. However, the Campaign immunization rejection rate was relatively high for the south eastern Nigeria where it is often assumed that non-compliance is not a problem. Similarly, the proportions of mothers with wrong knowledge and poor perception of immunization require policy attention. Maternal education was significantly associated with knowledge and acceptance of immunization. These findings are important in the design and implementation of childhood immunization programmes

Topological defects at smectic interfaces as a potential tool for the biosensing of living microorganisms

Characterizing the anchoring properties of smectic liquid crystals (LCs) in contact with bacterial solutions is crucial for developing biosensing platforms. In this study, we investigate the anchoring properties of a smectic LC when exposed to Bacillus Subtilis and Escherichia coli bacterial solutions using interfaces with known anchoring properties. By monitoring the optical response of the smectic film, we successfully distinguish different types of bacteria, leveraging the distinct changes in the LC's response. Through a comprehensive analysis of the interactions between bacterial proteins and the smectic interface, we elucidate the potential underlying mechanisms responsible for these optical changes. Additionally, we introduce the utilization of topological defects; the focal conic domains (FCDs), at the smectic interface as an indicative measure of the bacterial concentration. Our findings demonstrate the significant potential of smectic LCs and their defects for biosensing applications and contribute to our understanding of bacteria- LC interactions, paving the way for advancements in pathogen detection and protein-based sensing

Dilute Acid Hydrolysis of Cowpea Hulls: A Kinetic Study

In this study, dilute acid hydrolysis of cowpea hulls was carried out in two stages under the following conditions: pre-hydrolysis (4%v/v H2SO4, 121˚C, 30 minutes) and hydrolysis ( at 10% and 15% v/v H2SO4,varied at different temperatures 150 oC, 160 oC, 170 oC and 180 oC for 2.5 hrs.). The substrate was characterized using both Fourier transform infrared spectroscopy and proximate analysis. The percentage lignocellulosic composition of the substrate was obtained for cellulose, hemicellulose and lignin as 34%, 14% and 4.7% respectively. Maximum glucose concentration of 8.09g was obtained using 10%v/v acid concentration at 170˚C after a reaction time of 90min. Saeman’s model gave a good fit for the experimental data. Activation energy for glucose formation using 10%v/v and 15%v/v H2SO4 was obtained as 38.28KJ and 82.204KJ respectively. From the results obtained it can be concluded that cowpea hulls can be converted to a useful product