Development of a process for producing ribbon shaped filaments

Silicon carbide (SiC) ribbon filaments were produced on a carbon ribbon substrate, about 1500 microns (60 mils) wide and 100 microns (4 mils) thick in lengths up to 2 meters (6 ft), and with tensile strengths up to 142 KN/cm sq (206 Ksi). During the course of the study, ribbon filaments of boron were also produced on the carbon ribbon substrate; the boron ribbon produced was extremely fragile. The tensile strength of the SiC ribbon was limited by large growths or flaws caused by anomalies at the substrate surface; these anomalies were either foreign dirt or substrate imperfections or both. Related work carried out on round 100 micron (4 mils) diameter SiC filaments on a 33 micron (1.3 mil) diameter, very smooth carbon monofilament substrate has shown that tensile strengths as high as 551 KN/cm sq (800 Ksi) are obtainable with the SiC-carbon round substrate combination, and indicates that if the ribbon substrate surface and ribbon deposition process can be improved similar strengths can be realizable. Cost analysis shows that 100 micron x 5-10 micron SiC ribbon can be very low cost reinforcement material

Non-conventional approaches to food processing in CELSS, 1. Algal proteins: Characterization and process optimization

Protein isolate obtained from green algae cultivated under controlled conditions was characterized. Molecular weight determination of fractionated algal proteins using SDS-polyacrylamide gel electrophoresis revealed a wide spectrum of molecular weights ranging from 15,000 to 220,000. Isoelectric points of dissociated proteins were in the range of 3.95 to 6.20. Amino acid composition of protein isolate compared favorably with FAO standards. High content of essential amino acids leucine, valine, phenylalanine and lysine make algal protein isolate a high quality component of closed ecological life support system diets. To optimize the removal of algal lipids and pigments supercritical carbon dioxide extraction (with and without ethanol as a co-solvent) was used. Addition of ethanol to supercritical carbon dioxide resulted in more efficient removal of algal lipids and produced protein isolate with a good yield and protein recovery. The protein isolate extracted by the above mixture had an improved water solubility

Development of adjacent segment disease following multilevel anterior cervical discectomy and fusion surgery

BACKGROUND: Cervical spondylosis, a degenerative disease of the spine, is a common medical condition that results in significant morbidity, loss of function, and financial burden on the healthcare system in the United States. The disease ranges in severity from axial pain, which is among the most common medical complaints encountered in healthcare, to severe neurological symptoms such a myelopathy and radiculopathy, which may require surgical intervention. Anterior cervical discectomy and fusion (ACDF) has been established as a gold standard for safe and effective surgical treatment of cervical spondylotic myelopathy (CSM) and/or radiculopathy. However, there are significant complications that are associated with surgical intervention, including the development of pathology at the spinal levels adjacent to the fusion level(s), known, as adjacent segment disease (ASD). LITERATURE REVIEW: ASD has been studied in ACDF surgery, however there are a limited number of large studies that evaluate the correlation between the number of fused spinal levels and the rate of development of symptomatic and radiographic ASD. Mechanisms for the pathogenesis of ASD have been proposed and some are supported by in vitro cadaveric studies, but there is not yet conclusive and strong in vivo evidence in the literature. PROJECT PROPOSAL: This retrospective cohort study will be comparing rates of ASD development following short segment (one and two-level), and long segment (three or more levels) ACDF in patients with a minimum of three years of follow-up. Patients are evaluated for ASD via review of electronic medical records, including operative reports, outpatient and hospital charts, and evaluation of imaging studies. Images are assessed for radiographic ASD using the Kellgren-Lawrence criteria, and these results are subsetquently evaluated for correlation with symptomatic ASD. This study aims at investigating the incidence rates and relative risk of developing ASD and evaluate for statistically significant difference using chi-square analysis. CONCLUSION: More research is still needed to confirm the mechanism of pathogenesis of ASD and determine the effect that length of fusion construct has on the incidence of this disease. Further information will help guide physicians in their clinical decision making in the surgical treatment of patients with ACDF and those that subsequently develop ASD

Complete Genome Sequence of the Pantoea Phage AH07

Bacteriophages of the phyllosphere have not been extensively described, despite their role in bacterial communities on this plant organ. Here, we describe a temperate Pantoea phage, AH07, that was isolated from the leaves of horse chestnut trees. The 37,859-bp linear double-stranded DNA genome contains 58 putative genes, including an integration cassette

Complete Genome Sequences of Four Phages of the Horse Chestnut Phyllosphere

Bacteriophages play important roles in determining bacterial communities, including plant microbiota. Here, we describe four lytic phages, three Siphoviridae and one Podoviridae, isolated from four different bacterial species found on the leaves of horse chestnut trees. Their double-stranded DNA (dsDNA) genomes range from 39,095 to 46,062 bp and contain 51 to 70 genes

Genome Sequences of Erwinia Phyllophages AH04 and AH06

Although crucial in shaping bacterial communities, few bacteriophages of the phyllosphere have been described. We provide genome data for two Myoviridae phages, AH04 and AH06, isolated on Erwinia billingiae strains. AH04 shares limited genetic similarity with previously described phages, while AH06 shares over 75% similarity with various Erwinia phages

Membrane localization of the ToxR winged-helix domain is required for TcpP-mediated virulence gene activation in Vibrio cholerae

ToxR is a bitopic membrane protein that controls virulence gene expression in Vibrio cholerae . Its cytoplasmic domain is homologous to the winged helix–turn–helix (‘winged helix’) DNA-binding/transcription activation domain found in a variety of prokaryotic and eukaryotic regulators, whereas its periplasmic domain is of ill-defined function. Several genes in V. cholerae are regulated by ToxR, but by apparently different mechanisms. Whereas ToxR directly controls the transcription of genes encoding two outer membrane proteins, OmpU and OmpT, it co-operates with a second membrane-localized transcription factor called TcpP to activate transcription of the gene encoding ToxT, which regulates transcription of cholera toxin ( ctxAB ) and the toxin-co-regulated pilus ( tcp ). To determine the requirements for gene activation by ToxR, different domains of the protein were analysed for their ability to control expression of toxT , ompU and ompT . Soluble forms of the cytoplasmic winged-helix domain regulated ompU and ompT gene expression properly but did not activate toxT transcription. Membrane localization of the winged helix was sufficient for both omp gene regulation and TcpP-dependent toxT transcription, irrespective of the type of periplasmic domain or even the presence of a periplasmic domain. These results suggest that (i) the major function for membrane localization of ToxR is for its winged-helix domain to co-operate with TcpP to activate transcription; (ii) the periplasmic domain of ToxR is not required for TcpP-dependent activation of toxT transcription; and (iii) membrane localization is not a strict requirement for DNA binding and transcription activation by ToxR.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73850/1/j.1365-2958.2003.03398.x.pd

The two faces of ToxR: activator of ompU , co‐regulator of toxT in Vibrio cholerae

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87152/1/j.1365-2958.2011.07681.x.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/87152/2/MMI_7681_sm_FigureS1_TableS1-2.pd

Complete Genome Sequences of Two Temperate Bacillus subtilis Phages Isolated at Tumamoc Hill Desert Laboratory

Bacteriophages are important in structuring bacterial communities, including desert soils dominated by Bacillus species. Here, we describe two genetically similar temperate phages isolated on a Bacillus subtilis strain from soil in Tucson, Arizona. Their double-stranded DNA (dsDNA) genomes contain 98 and 102 genes, with a set of 4 genes being found in only one phage

Activation of both acfA and acfD transcription by Vibrio cholerae ToxT requires binding to two centrally located DNA sites in an inverted repeat conformation

The Gram-negative bacterium Vibrio cholerae is the infectious agent responsible for the disease Asiatic cholera. The genes required for V. cholerae virulence, such as those encoding the cholera toxin (CT) and toxin-coregulated pilus (TCP), are controlled by a cascade of transcriptional activators. Ultimately, the direct transcriptional activator of the majority of V. cholerae virulence genes is the AraC/XylS family member ToxT protein, the expression of which is activated by the ToxR and TcpP proteins. Previous studies have identified the DNA sites to which ToxT binds upstream of the ctx operon, encoding CT, and the tcpA operon, encoding, among other products, the major subunit of the TCP. These known ToxT binding sites are seemingly dissimilar in sequence other than being A/T rich. Further results suggested that ctx and tcpA each has a pair of ToxT binding sites arranged in a direct repeat orientation upstream of the core promoter elements. In this work, using both transcriptional lacZ fusions and in vitro copper-phenanthroline footprinting experiments, we have identified the ToxT binding sites between the divergently transcribed acfA and acfD genes, which encode components  of the accessory colonization factor required for efficient intestinal colonization by V. cholerae . Our results indicate that ToxT binds to a pair of DNA sites between acfA and acfD in an inverted repeat orientation. Moreover, a mutational analysis of the ToxT binding sites indicates that both binding sites are required by ToxT for transcriptional activation of both acfA and acfD . Using copper-phenanthroline footprinting to assess the occupancy of ToxT on DNA having mutations in one of these binding sites, we found that protection by ToxT of the unaltered binding site was not affected, whereas protection by ToxT of the mutant binding site was significantly reduced in the region of the mutations. The results of further footprinting experiments using DNA templates having +5 bp and +10 bp insertions between the two ToxT binding sites indicate that both binding sites are occupied by ToxT regardless of their positions relative to each other. Based on these results, we propose that ToxT binds independently to two DNA sites between acfA and acfD to activate transcription of both genes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73166/1/j.1365-2958.2005.04589.x.pd