A Superoxide Dismutase C Mutant of Haemophilus ducreyi Is Virulent in Human Volunteers

Haemophilus ducreyi produces a periplasmic copper-zinc superoxide dismutase (Cu-Zn SOD), which is thought to protect the organism from exogenous reactive oxygen species generated by neutrophils during an inflammatory response. We had previously identified the gene, sodC, responsible for the production and secretion of Cu-Zn SOD and constructed an isogenic H. ducreyi strain with a mutation in the sodC gene (35000HP-sodC-cat). Compared to the parent, the mutant does not survive in the presence of exogenous superoxide (L. R. San Mateo, M. Hobbs, and T. H. Kawula, Mol. Microbiol. 27:391-404, 1998) and is impaired in the swine model of H. ducreyi infection (L. R. San Mateo, K. L. Toffer, P. E. Orndorff, and T. H. Kawula, Infect. Immun. 67:5345-5351, 1999). To test whether Cu-Zn SOD is important for bacterial survival in vivo, six human volunteers were experimentally infected with 35000HP and 35000HP-sodC-cat and observed for papule and pustule formation. Papules developed at similar rates at sites inoculated with the mutant or parent. The pustule formation rates were 75% (95% confidence intervals [CI], 43 to 95%) at 12 parent-inoculated sites and 67% (95% CI, 41 to 88%) at 18 mutant-inoculated sites (P = 0.47). There was no significant difference in levels of H. ducreyi recovery from mutant- and parent-inoculated biopsy sites. These results suggest that expression of Cu-Zn SOD does not play a major role in the survival of this pathogen in the initial stages of experimental infection of humans

Investigating the driving mechanisms of coronal mass ejections

The objective of this investigation was to first examine the kinematics of coronal mass ejections (CMEs) using EUV and coronagraph images, and then to make a comparison with theoretical models in the hope to identify the driving mechanisms of the CMEs. We have studied two CMEs which occurred on 2006 Dec. 17 (CME06) and 2007 Dec. 31 (CME07). The models studied in this work were catastrophe, breakout, and toroidal instability models. We found that after the eruption, the accelerations of both events exhibited a drop before increasing again. Our comparisons with the theories suggested that CME06 can be best described by a hybrid of the catastrophe and breakout models while CME07 is most consistent with the breakout model.Comment: 9 pages 7 figure

Period Integrals of CY and General Type Complete Intersections

We develop a global Poincar\'e residue formula to study period integrals of families of complex manifolds. For any compact complex manifold $X$ equipped with a linear system $V^*$ of generically smooth CY hypersurfaces, the formula expresses period integrals in terms of a canonical global meromorphic top form on $X$. Two important ingredients of our construction are the notion of a CY principal bundle, and a classification of such rank one bundles. We also generalize our construction to CY and general type complete intersections. When $X$ is an algebraic manifold having a sufficiently large automorphism group $G$ and $V^*$ is a linear representation of $G$, we construct a holonomic D-module that governs the period integrals. The construction is based in part on the theory of tautological systems we have developed in the paper \cite{LSY1}, joint with R. Song. The approach allows us to explicitly describe a Picard-Fuchs type system for complete intersection varieties of general types, as well as CY, in any Fano variety, and in a homogeneous space in particular. In addition, the approach provides a new perspective of old examples such as CY complete intersections in a toric variety or partial flag variety.Comment: An erratum is included to correct Theorem 3.12 (Uniqueness of CY structure

Mini-review on substrate & inoculum loadings for anaerobic co-digestion of food waste

Increasing production of food waste can lead to major environmental pollution if it is disposed without proper control in many countries. Food waste can be regarded as a resource rather than unwanted discard due to its high potential for resource recovery. Anaerobic digestion of food waste has shown promising potential for food waste treatment and valorisation by producing biogas as a renewable energy and digestate as fertiliser. Food waste has high biogas potential due to the presence of highly labile organic matter but this can lead to process instability. The process instability is often linked to the imbalance of process intermediates that affects the microbial community. Common parameters that are crucial for ensuring optimal metabolic activity of anaerobes includes temperature, pH, carbon-nitrogen ratio, organic loading rate, retention time and nutrient concentration. Co-digestion of food waste with other feedstocks are increasingly being practiced for better nutrient balance and reducing chances for rapid acidfication. The optimum conditions for the process has been shown to vary following different microbial inoculants and loadings of the respective substrates. This study aims to review only the effect of substrate and inoculum used during the AD of food waste, including the type of co-digested substrate, the mixing ratio, the microbial inoculant used and the substrate to inoculum ratio

An insight into curcumin-based photosensitization as a promising and green food preservation technology

Consumer awareness on the side effects of chemical preservatives has increased the demand for natural preservation technologies. An efficient and sustainable alternative to current conventional preservation techniques should guarantee food safety and retain its quality with minimal side effects. Photosensitization, utilizing light and a natural photosensitizer, has been postulated as a viable and green alternative to the current conventional preservation techniques. The potential of curcumin as a natural photosensitizer is reviewed in this paper as a practical guide to develop a safe and effective decontamination tool for industrial use. The fundamentals of the photosensitization mechanism are discussed, with the main emphasis on the natural photosensitizer, curcumin, and its application to inactivate microorganisms as well as to enhance the shelf life of foods. Photosensitization has shown promising results in inactivating a wide spectrum of microorganisms with no reported microbial resistance due to its particular lethal mode of targeting nucleic acids. Curcumin as a natural photosensitizer has recently been investigated and demonstrated efficacy in decontamination and delaying spoilage. Moreover, studies have shown the beneficial impact of an appropriate encapsulation technique to enhance the cellular uptake of photosensitizers, and therefore, the phototoxicity. Further studies relating to improved delivery of natural photosensitizers with inherent poor solubility should be conducted. Also, detailed studies on various food products are warranted to better understand the impact of encapsulation on curcumin photophysical properties, photo-driven release mechanism, and nutritional and organoleptic properties of treated foods

Wire scanners for beam size and emittance measurements at the SLC

The SLC wire scanner beam profile monitors provide accurate beam size and emittance measurements for each bunch in the three bunch SLC beam. The beam size measurement error for typical 50GeV SLC linac beams (100{mu}m {sigma}({sub x,y})) is better than 5{mu}m. Beam profile measurements can be performed throughout much of the SLC with no interruption to normal machine operation and no adverse impact on interaction region detector backgrounds. The linac input and output emittance is determined using sets of four scanners spaced by {approximately}45{degrees} betatron phase advance. Each scanner contains three wires, x, y and u (45{degrees}), from which an estimate of the x-y coupling can be obtained. Advanced high level control software allows the use of wire scanner data in feedback and beam optimization procedures. Non-invasive scans are performed almost continually and the results are logged so that long term trends in emittance can be examined. In this paper we describe the design, construction, performance and uses of SLC wire scanners. 7 refs., 3 figs., 1 tab

How does a cadaver model work for testing ultrasound diagnostic capability for rheumatic-like tendon damage?

To establish whether a cadaver model can serve as an effective surrogate for the detection of tendon damage characteristic of rheumatoid arthritis (RA). In addition, we evaluated intraobserver and interobserver agreement in the grading of RA-like tendon tears shown by US, as well as the concordance between the US findings and the surgically induced lesions in the cadaver model. RA-like tendon damage was surgically induced in the tibialis anterior tendon (TAT) and tibialis posterior tendon (TPT) of ten ankle/foot fresh-frozen cadaveric specimens. Of the 20 tendons examined, six were randomly assigned a surgically induced partial tear; six a complete tear; and eight left undamaged. Three rheumatologists, experts in musculoskeletal US, assessed from 1 to 5 the quality of US imaging of the cadaveric models on a Likert scale. Tendons were then categorized as having either no damage, (0); partial tear, (1); or complete tear (2). All 20 tendons were blindly and independently evaluated twice, over two rounds, by each of the three observers. Overall, technical performance was satisfactory for all items in the two rounds (all values over 2.9 in a Likert scale 1-5). Intraobserver and interobserver agreement for US grading of tendon damage was good (mean κ values 0.62 and 0.71, respectively), with greater reliability found in the TAT than the TPT. Concordance between US findings and experimental tendon lesions was acceptable (70-100 %), again greater for the TAT than for the TPT. A cadaver model with surgically created tendon damage can be useful in evaluating US metric properties of RA tendon lesions

On Unbounded Composition Operators in L2L^2-Spaces

Fundamental properties of unbounded composition operators in $L^2$-spaces are studied. Characterizations of normal and quasinormal composition operators are provided. Formally normal composition operators are shown to be normal. Composition operators generating Stieltjes moment sequences are completely characterized. The unbounded counterparts of the celebrated Lambert's characterizations of subnormality of bounded composition operators are shown to be false. Various illustrative examples are supplied

Design, construction, and beam tests of a rotatable collimator prototype for high-intensity and high-energy hadron accelerators

A rotatable-jaw collimator design was conceived as a solution to recover from catastrophic beam impacts which would damage a collimator at the Large Hadron Collider (LHC) or its High-Luminosity upgrade (HL-LHC). One such rotatable collimator prototype was designed and built at SLAC and delivered to CERN for tests with LHC-type circulating beams in the Super Proton Synchrotron (SPS). This was followed by destructive tests at the dedicated High Radiation to Materials (HiRadMat) facility to validate the design and rotation functionality. An overview of the collimator design, together with results from tests without and with beam are presented