Comparative evaluation of yogurt and low-fat cheddar cheese as delivery media for probiotic Lactobacillus casei

This study used Lactobacillus casei 334e, an erythromycin-resistant derivative of ATCC 334, as a model to evaluate viability and acid resistance of probiotic L. casei in low-fat Cheddar cheese and yogurt. Cheese and yogurt were made by standard methods and the probiotic L. casei adjunct was added at approximately 10(7) CFU/g with the starter cultures. Low-fat cheese and yogurt samples were stored at 8 and 2 degrees C, respectively, and numbers of the L. casei adjunct were periodically determined by plating on MRS agar that contained 5 microg/mL of erythromycin. L. casei 334e counts in cheese and yogurt remained at 10(7) CFU/g over 3 mo and 3 wk, respectively, indicating good survival in both products. Acid challenge studies in 8.7 mM phosphoric acid (pH 2) at 37 degrees C showed numbers of L. casei 334e in yogurt dropped from 10(7) CFU/g to less than 10(1) CFU/g after 30 min, while counts in cheese samples dropped from 10(7) CFU/g to about 10(5) after 30 min, and remained near 10(4) CFU/g after 120 min. As a whole, these data showed that low-fat Cheddar cheese is a viable delivery food for probiotic L. casei because it allowed for good survival during storage and helped protect cells against the very low pH that will be encountered during stomach transit.     

Lipids from Wastewater-Activated Sludge Cultivated on Acetic Acid as Potential Alternatives to High-Value Oils and Fats

This study focuses on new interpretations of the published literature by statistically evaluating the potential of microbial lipids from activated sludge (AS) as alternatives to high-value oils and fats. There are two data analysis stages involved in this study after compilation and organization of fatty acid profiles from the literature databases: (1) comparison of fatty acid profiles of the cultivated AS lipids with that of oils and fats found in the literature databases, and (2) hierarchical cluster analysis of the fatty acids of the combined dataset of literature oils and fats, and the AS lipids. Results show that fatty acid profiles of lipids from cultivated AS were similar to the fatty acid profiles of some oils and fats of plant, animal, single-microbial cultures, and algal origins; hence, lipids from AS could be potential alternatives to specialty oils and fats. The cultivation conditions of AS during lipid content enhancement may influence lipid application.     

Enabling BPR in Maintenance Through a Performance Measurement System Framework

With ever-increasing importance, plant maintenance is no more regarded as second line or non-productive activity. It is about time maintenance received due attention from various business improvement initiatives such as total quality management or business process reengineering (BPR). This paper builds on previous work by the authors that examines the role of performance measurement systems (PMS) in maintenance, with particular reference to developing a new PMS framework using the quality function deployment (QFD) technique. In the light of the fact that there is only limited evidence of BPR applications pertinent to equipment maintenance, this paper explores the use of the PMS framework to enable and guide sound BPR endeavors in maintenance. Condensed literature on BPR is presented followed by an outline of the PMS framework. The benefits of utilizing such a framework are examined with reference to BPR in maintenance. The practical implications of the findings are discussed based on a case study conducted in a local company.     

Passage of selected heavy metals from Sphaerotilus (bacteria: chlamydobacteriales) to Paramecium caudatum (protozoa: ciliata)

Sphaerotilus, a bacterium occurring in polluted waters, was found to take up Zn, Pb, Ni and Mn. Metal-containing cultures of this bacterium were employed to feed the protozoan Paramecium caudatum, and analytical results revealed the accumulation of Zn, Pb and Ni. Since Sphaerotilus was the only food source for paramecia during this study, the results indicate that trace amounts of metals were passed from bacteria to protozoa in a predator-prey relationship.     

New Orleans Levee System Performance during Hurricane Katrina: London Avenue and Orleans Canal South

Hurricane Katrina was one of the worst natural disasters in U.S. history. The effects of the hurricane were particularly devastating in the city of New Orleans. Most of the damage was due to the failure of the levee system that surrounds the city to protect it from flooding. This paper presents the results of centrifuge models conducted at Rensselaer Polytechnic Institute and the U.S. Army Corps of Engineers simulating the behavior of the levees at London Avenue North and South that failed during Hurricane Katrina. Those levees failed without being overtopped by the storm surge. Also included are the results of a centrifuge model of one levee section at Orleans Canal South, which did not fail during the hurricane. The key factor of the failure mechanism of the London Avenue levees was the formation of a gap between the flooded side of the levee and the sheetpile. This gap triggered a reduction of the strength at the foundation of the protected side of the levee. The results are fully consistent with field observations.     

Persuasive communication and proenvironmental behaviours: How message tailoring and message framing can improve the integration of behaviours through self-determined motivation.

Public concern about environmental issues has grown substantially in the last two decades. As a consequence, the promotion of environmentally conscious behaviours that are integrated in people's lifestyle has become an ongoing and important challenge. Persuasive messages are often perceived as the first step in efforts to motivate people to change a specific behaviour. In this article, the authors propose that (a) tailoring messages according to proposed processes underlying behaviour change (i.e., being aware of a problem, deciding what to do, initiating, and implementing a behaviour); and (b) framing these messages in terms of whether they serve intrinsic goals (i.e., health, well-being) as opposed to extrinsic goals (i.e., make or save money, comfort) could make messages more effective by progressively increasing the level of self-determined motivation of the targeted population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Single- and double-difference algorithms for position and time-delay calibration of transducer-elements in a sparse array

A method for the calibration of the position and time delay of transducer elements in a large, sparse array used for underwater, high-resolution, ultrasound imaging has been described in a previous work. This algorithm is based on the direct algorithm used in the global positioning system (GPS), but the wave propagation speed is treated as one of the to-be-calibrated parameters. In this article, the performance of two other commonly used GPS algorithms, namely the single-difference algorithm and the double-difference algorithm, is evaluated. The calibration of the propagation speed also is integrated into these two algorithms. Furthermore, a novel, least-squares method is proposed to calibrate the time delay associated with each transducer element for these two algorithms. The performances of these algorithms are theoretically analyzed and evaluated using numerical analysis and simulation study. The performance of the direct algorithm, the single-difference algorithm, and the double-difference algorithm is compared. It was found that the single-difference algorithm has the best performance among the three algorithms for the current application, and it is capable of calibrating the position and time delay of transducer elements to an accuracy of one-tenth of a wavelength.     

Origin of HIV-1 in the chimpanzee Pan troglodytes troglodytes

The human AIDS viruses human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) represent cross-species (zoonotic) infections. Although the primate reservoir of HIV-2 has been clearly identified as the sooty mangabey (Cercocebus atys), the origin of HIV-1 remains uncertain. Viruses related to HIV-1 have been isolated from the common chimpanzee (Pan troglodytes), but only three such SIVcpz infections have been documented, one of which involved a virus so divergent that it might represent a different primate lentiviral lineage. In a search for the HIV-1 reservoir, we have now sequenced the genome of a new SIVcpzstrain (SIVcpzUS) and have determined, by mitochondrial DNA analysis, the subspecies identity of all known SIVcpz-infected chimpanzees. We find that two chimpanzee subspecies in Africa, the central P. t. troglodytes and the eastern P. t. schweinfurthii, harbour SIVcpz and that their respective viruses form two highly divergent (but subspecies-specific) phylogenetic lineages. All HIV-1 strains known to infect man, including HIV-1 groups M, N and O, are closely related to just one of these SIVcpz lineages, that found in P. t. troglodytes. Moreover, we find that HIV-1 group N is a mosaic of SIVcpzUS- and HIV-1-related sequences, indicating an ancestral recombination event in a chimpanzee host. These results, together with the observation that the natural range of P. t. troglodytes coincides uniquely with areas of HIV-1 group M, N and O endemicity, indicate that P. t. troglodytes is the primary reservoir for HIV-1 and has been the source of at least three independent introductions of SIVcpz into the human population.     

Bacteriophages and biotechnology: a review

Bacteriophages are viruses whose hosts are bacterial cells. Like all viruses, phages are metabolically inert in their extra‐cellular form, reproducing only after infecting suitable host bacteria. Discovered over 80 years ago, they have played a key role in the development of modern biotechnology. Their initial isolation appeared to offer the first therapeutic for the control of infectious disease. The discovery of antibiotics in the 1940s eclipsed bacteriophage‐based therapies although, with the increase in multiply drug‐resistant pathogens, bacteriophages are being re‐evaluated as the basis of new therapeutic strategies. Their defined host specificity facilitated their application in the typing and identification of a wide range of bacteria. Bacteriophage typing schemes were developed for most groups of pathogenic of bacteria and more recently their host specificity has been applied to the development of bacterial detection and diagnostic strategies. The advance in molecular biology over the past 30 years has been built on the study of phage structure and genetics carried out through the 1950s and 1960s. Restriction endonucleases which form the basis of molecular cloning were developed following studies of phage infection and many phage enzymes provide tools for the molecular biologist. The technique of phage display has more recently provided a powerful technique for the identification and optimisation of ligands for antibodies and other biomolecules. In the environment they have been widely applied as tracers, as indicators of pollution and in the monitoring and validation of biological filters. While providing a valuable resource to the development of modern biotechnology, their ability to mobilise and transfer toxin genes in the environment is viewed with concern. They also present a continuing challenge to the fermentation and in particular, the dairy industry, where phage infection can prove commercially disastrous. © 2000 Society of Chemical Industry