Incidence of foodborne illnesses reported by the foodborne diseases active surveillance network (FoodNet)-1997. FoodNet Working Group

In 1997, the Foodborne Diseases Active Surveillance Program (FoodNet) conducted active surveillance for culture-confirmed cases of Campylobacter, Escherichia coli O157, Listeria, Salmonella, Shigella, Vibrio, Yersinia, Cyclospora, and Cryptosporidium in five Emerging Infections Program sites. FoodNet is a collaborative effort of the Centers for Disease Control and Prevention's National Center for Infectious Diseases, the United States Department of Agriculture's Food Safety and Inspection Service, the Food and Drug Administration's Center for Food Safety and Applied Nutrition, and state health departments in California, Connecticut, Georgia, Minnesota, and Oregon. The population under active surveillance for foodborne infections was approximately 16.1 million persons or roughly 6% of the United States Population. Through weekly or monthly contact with all clinical laboratories in these sites, 8,576 total isolations were recorded: 2,205 cases of salmonellosis, 1,273 cases of shigellosis, 468 cases of cryptosporidiosis, 340 of E. coli O157:H7 infections, 139 of yersiniosis, 77 of listeriosis, 51 of Vibrio infections, and 49 of cyclosporiasis. Results from 1997 demonstrate that while there are regional and seasonal differences in reported incidence rates of certain bacterial and parasitic diseases, and that some pathogens showed a change in incidence from 1996, the overall incidence of illness caused by pathogens under surveillance was stable. More data over more years are needed to assess if observed variations in incidence reflect yearly fluctuations or true changes in the burden of foodborne illness.     

PETROLEUM EXPLORATION IN THE ETHIOPIAN RED SEA

The Red Sea is a pericratonic Upper Tertiary basin which developed on the continental margin of Africa during the separation of Arabia from Africa, and is characterized by halokinetic tectonics in the upper stuctual stage and block-rifting in the lower strctual stage. The margin is overprinted on a pre-rift Mesozoic platform.
Hydrocarbon exploration interest in the Ethiopian Red Sea area is based on three objectives, which correspond to stages in geotectonic evolution: Mesozic pre-rift targets; Miocene rift presalt targets; and upper Miocene-Pliocene post-rift drift sequences.
Reservoirs with appropriate sealing units (salt or shale) have been recorded. Models of sourcerock maturation using observed geothermal gradients are consistent with anaytical resuits, and prove that oil generation and preservation is to be xpected in the Ethiopian Red Sea.     

Examination of heat transfer correlations and a model for flow boiling of R134a in small diameter tubes

Analysis of various existing correlations including a three-zone evaporation model is made using a comparison with recent experimental results obtained in this study. Flow boiling heat transfer experiments were conducted with two stainless steel tubes of internal diameter 4.26 mm and 2.01 mm. The working fluid was R134a and parameters were varied in the range: mass flux 100–500 kg/m²s; pressure 8–12 bar; quality up to 0.9; heat flux 13–150 kW/m². The local heat transfer coefficient was independent of vapour quality when this was less than about 40–50% in the 4.26 mm tube and 20–30% in the 2.01 mm tube. Local transient dryout was deduced when the quality was above these values. Furthermore, at high heat flux values the heat transfer coefficient decreased with vapour quality for the entire quality range indicating early occurrence of dryout.Existing correlations, which are based on large tube boiling processes, do not predict the present small diameter data to a satisfactory degree. A better agreement is observed with the recent, state-of-the-art, three-zone evaporation model. However, the model does not predict the effect of diameter and the partial dryout. Nevertheless, the observation suggests that the flow pattern based modelling approach performs at least as well as empirical correlations that are based on macroscale modelling. Aspects of the model that need further consideration are also proposed in this study.     

Quantitative pO2 imaging in vivo with perfluorocarbon F-19 NMR: tracking oxygen from the airway through the blood to organ tissues

The physiological redistribution of perfluorocarbon (PFC) compounds to liver, spleen, bone marrow, and lung after intravenous (i.v.) or intraperitoneal (IP) administration of PFC emulsions affords the unique opportunity for non-invasive monitoring of oxygenation status of these organs and tissues utilizing fluorine (F-19) nuclear magnetic resonance (NMR) imaging techniques. PFCs also may be introduced directly into the pulmonary airways by procedures such as liquid ventilation, intratracheal instillation, or aerosol inhalation. Considerations of importance when establishing methodology for accurate quantitation of oxygen partial pressure (pO2) in vivo using F-19 NMR include: 1.) error analysis of the calibration curves which relate pO2 to the measured PFC F-19 relaxation rate, 2.) optimization of the NMR pulse sequence for efficient oxygen sensitive data acquisition and, 3.) fluorine signal independence from emulsion aqueous phase bioconstituents. The porcine model was investigated at 0.14T following i.v. or IP administration of the PFC emulsion containing perfluorotributylamine (FC-43) to demonstrate the capability for tracking oxygen with F-19 NMR from the lung through the blood to selected organ tissues. Quantitative pO2 projection images and isobaric contour graphs were derived for the liver, spleen, and lungs as a function of inspired oxygen. Blood pO2 levels in aorta, pulmonary artery, and hepatic vein were monitored simultaneously with NMR imaging for correlative analysis.     

Crops that feed the world 10. Past successes and future challenges to the role played by wheat in global food security

Wheat is fundamental to human civilization and has played an outstanding role in feeding a hungry world and improving global food security. The crop contributes about 20 % of the total dietary calories and proteins worldwide. Food demand in the developing regions is growing by 1 % annually and varies from 170 kg in Central Asia to 27 kg in East and South Africa. The developing regions (including China and Central Asia) account for roughly 53 % of the total harvested area and 50 % of the production. Unprecedented productivity growth from the Green Revolution (GR) since the 1960s dramatically transformed world wheat production, benefitting both producers and consumers through low production costs and low food prices. Modern wheat varieties were adopted more rapidly than any other technological innovation in the history of agriculture, recently reaching about 90 % of the area in developing regions. One of the key challenges today is to replace these varieties with new ones for better sustainability. While the GR “spared” essential ecosystems from conversion to agriculture, it also generated its own environmental problems. Also productivity increase is now slow or static. Achieving the productivity gains needed to ensure food security will therefore require more than a repeat performance of the GR of the past. Future demand will need to be achieved through sustainable intensification that combines better crop resistance to diseases and pests, adaptation to warmer climates, and reduced use of water, fertilizer, labor and fuel. Meeting these challenges will require concerted efforts in research and innovation to develop and deploy viable solutions. Substantive investment will be required to realize sustainable productivity growth through better technologies and policy and institutional innovations that facilitate farmer adoption and adaptation. The enduring lessons from the GR and the recent efforts for sustainable intensification of cereal systems in South Asia and other regions provide useful insights for the future.     

Quality-Related Enzymes in Plant-Based Products: Effects of Novel Food Processing Technologies Part 2: Pulsed Electric Field Processing

Pulsed electric field (PEF) processing is an effective technique for the preservation of pumpable food products as it inactivates vegetative microbial cells at ambient to moderate temperature without significantly affecting the nutritional and sensorial quality of the product. However, conflicting views are expressed about the effect of PEF on enzymes. In this review, which is part 2 of a series of reviews dealing with the effectiveness of novel food preservation technologies for controlling enzymes, the scientific literature over the last decade on the effect of PEF on plant enzymes is critically reviewed to shed more light on the issue. The existing evidence indicates that PEF can result in substantial inactivation of most enzymes, although a much more intense process is required compared to microbial inactivation. Depending on the processing condition and the origin of the enzyme, up to 97% inactivation of pectin methylesterase, polyphenol oxidase, and peroxidase as well as no inactivation have been reported following PEF treatment. Both electrochemical effects and Ohmic heating appear to contribute to the observed inactivation, although the relative contribution depends on a number of factors including the origin of the enzyme, the design of the PEF treatment chamber, the processing condition, and the composition of the medium.     

Crops that feed the world 6. Past successes and future challenges to the role played by maize in global food security

Maize is one of the most important food crops in the world and, together with rice and wheat, provides at least 30% of the food calories to more than 4.5 billion people in 94 developing countries. In parts of Africa and Mesoamerica, maize alone contributes over 20% of food calories. Maize is also a key ingredient in animal feed and is used extensively in industrial products, including the production of biofuels. Increasing demand and production shortfalls in global maize supplies have worsened market volatility and contributed to surging global maize prices. Climatic variability and change, and the consequent rise in abiotic and biotic stresses, further confound the problem. Unless concerted and vigorous measures are taken to address these challenges and accelerate yield growth, the outcome will be hunger and food insecurity for millions of poor consumers. We review the research challenges of ensuring global food security in maize, particularly in the context of climate change. The paper summarizes the importance of maize for food, nutrition and livelihood security and details the historical productivity of maize, consumption patterns and future trends. We show how crop breeding to overcome biotic and abiotic stresses will play a key role in meeting future maize demand. Attention needs to be directed at the generation of high yielding, stress-tolerant and widely-adapted maize varieties through judicious combination of conventional and molecular breeding approaches. The use of improved germplasm per se will not, however, be enough to raise yields and enhance adaptation to climate change, and will need to be complemented by improved crop and agronomic practices. Faced with emasculated state extension provision and imperfect markets, new extension approaches and institutional innovations are required that enhance farmers’ access to information, seeds, other inputs, finance and output markets. Over the long-term, large public and private sector investment and sustained political commitment and policy support for technology generation and delivery are needed to overcome hunger, raise the incomes of smallholder farmers and meet the challenges of growing demand for maize at the global level.     

Flow boiling in a 1.1 mm tube with R134a: Experimental results and comparison with model

A detailed comparison of flow boiling heat transfer results in a stainless steel tube of 1.1 mm internal diameter with results of a three-zone flow model are presented in this paper. The working fluid is R134a. Other parameters were varied in the range: mass flux 100–600 kg/m² s; heat flux 16–150 kW/m² and pressure 6–12 bar.The experimental results demonstrate that the heat transfer coefficient increases with heat flux and system pressure, but does not change with vapour quality when the quality is less than about 50% for low heat and mass flux values. The effect of mass flux is observed to be insignificant. For vapour quality values greater than 50% and at high heat flux values, the heat transfer coefficient does not depend on heat flux and decreases with vapour quality. This could be caused by dryout. The three-zone evaporation model predicts the experimental results fairly well, especially at relatively low pressure. However, the dryout region observed at high quality is highly over-predicted by the model. The sensitivity of the performance of the model to the three optimised parameters (confined bubble frequency, initial film thickness and end film thickness) and some preliminary investigation relating the critical film thickness for dryout to measured tube roughness are also discussed.     

One-Dimensional Semimechanistic Model for Flow Boiling Pressure Drop in Small to Micro Passages

Accurate predictions of two-phase pressure drop in small to micro-diameter passages are necessary for the design of compact and ultra-compact heat exchangers, which find wide application in process and refrigeration industries and in the cooling of electronics. A semimechanistic model of boiling two-phase pressure drop in the confined bubble regime is formulated, following the three-zone approach for heat transfer. The total pressure drop is calculated by time-averaging the pressure drops for single-phase liquid, elongated bubble with a thin liquid film, and single-phase vapor. The model results were compared with experimental data collected for a wide range of tube diameters (4.26, 2.88, 2.02, 1.1, and 0.52 mm) for R134a at pressures of 6–12 bar. In this model's present form, its predictions are close to those of the homogeneous flow model but it provides a platform for further development.     

The investigation and outcome of reported cases of elder abuse: the Forsyth County Aging Study

Deinococcus radiodurans is known as a radioresistant bacterium. For the construction of the shuttle vector, plasmids of this bacterium were isolated and investigated. At least two new plasmids in the cells of D. radiodurans MR1, KR1 and Sark were found in this experiment. However, a common plasmid among MR1, KR1 and Sark strains could not be found. These plasmids would be useful for the construction of the shuttle vector for cloning radioresistant genes of this bacterium.