377 research outputs found
Cut and project sets with polytopal window I: complexity
We calculate the growth rate of the complexity function for polytopal cut and project sets. This generalizes work of Julien where the almost canonical condition is assumed. The analysis of polytopal cut and project sets has often relied on being able to replace acceptance domains of patterns by so-called cut regions. Our results correct mistakes in the literature where these two notions are incorrectly identified. One may only relate acceptance domains and cut regions when additional conditions on the cut and project set hold. We find a natural condition, called the quasicanonical condition, guaranteeing this property and demonstrate by counterexample that the almost canonical condition is not sufficient for this. We also discuss the relevance of this condition for the current techniques used to study the algebraic topology of polytopal cut and project sets
Non-Speaking Autistic Participation in Liturgy and Church Life : (Non-)Speech Acts
Acknowledgements We are grateful to the Carnegie Trust for the Universities in Scotland for funding this research project. āFor the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission.āPeer reviewedPostprin
Effect of food-related stress conditions and loss of agr and sigB on seb promoter activity in S. aureus
Staphylococcal enterotoxin B (SEB) causes staphylococcal food poisoning and is produced in up to ten times higher quantities than other major enterotoxins. While Staphylococcus aureus growth is often repressed by competing flora, the organism exhibits a decisive growth advantage under some stress conditions. So far, data on the influence of food-related stressors and regulatory mutations on seb expression is limited and largely based on laboratory strains, which were later reported to harbor mutations. Therefore, the aim of this study was to investigate the influence of stress and regulatory mutations on seb promoter activity. To this end, transcriptional fusions were created in two strains, USA300 and HG003, carrying different seb upstream sequences fused to a blaZ reporter. NaCl, nitrite, and glucose stress led to significantly decreased seb promoter activity, while lactic acid stress resulted in significantly increased seb promoter activity. Loss of agr decreased seb promoter activity and loss of sigB increased promoter activity, with the magnitude of change depending on the strain. These results demonstrate that mild stress conditions encountered during food production and preservation can induce significant changes in seb promoter activity
Increasing the Field-of-View Radiation Efficiency of Optical Phased Antenna Arrays
Silicon photonics in conjunction with complementary metal-oxide-semiconductor
(CMOS) fabrication has greatly enhanced the development of integrated optical
phased arrays. This facilitates a dynamic control of light in a compact form
factor that enables the synthesis of arbitrary complex wavefronts in the
infrared spectrum. We numerically demonstrate a large-scale two dimensional
silicon-based optical phased array (OPA) composed of nanoantennas with circular
gratings that are balanced in power and aligned in phase, required for
producing elegant radiation patterns in the far field. For a wavelength of
1.55, we optmize two antennas for the OPA exhibting an upward radiation
efficiency as high as 90%, with almost 6.8% of optical power concentrated in
the field of view. Additionally, we believe that the proposed OPAs can be
easily fabricated and would have the ability of generating complex holographic
images, rendering them an attractive candidate for a wide range of applications
like LiDAR sensors, optical trapping, optogenetic stimulation and
augmented-reality displays
Membrane Properties of D-erythro-N-acyl Sphingomyelins and Their Corresponding Dihydro Species
AbstractWe have prepared acyl chain-defined D-erythro-sphingomyelins and D-erythro-dihydrosphingomyelins and compared their properties in monolayer and bilayer membranes. Surface pressure/molecular area isotherms of D-erythro-N-16:0-sphingomyelin (16:0-SM) and D-erythro-N-16:0-dihydrosphingomyelin (16:0-DHSM) show very similar packing properties, except that the expanded-to-condensed phase transition (crystallization) occurs at a lower surface pressure for 16:0-DHSM. The measured surface potential was generally about 100mV less for 16:0-DHSM monolayers compared to 16:0-SM monolayers. The condensed domains (crystals) that formed in 16:0-SM monolayers as a function of compression displayed star-shaped morphology when viewed under an epifluorescence microscope. 16:0-DHSM monolayers did not form similar crystals upon compression. 16:0-DHSM was degraded much faster by sphingomyelinase from Staphylococcus aureus than 16:0-SM (10-fold difference in enzyme activity needed for comparable hydrolytic rate). Cholesterol desorption from 16:0-DHSM to cyclodextrin was slightly slower (ā¼20%) than the rate measured from 16:0-SM monolayers (at 60mol % cholesterol). The bilayer melting temperature of 16:0-DHSM was 47.7Ā°C (ĪH 8.3kcal/mol) whereas it was 41.2Ā°C for 16:0-SM (ĪH 8.1kcal/mol). Cholesterol/16:0-DHSM bilayers (15mol % sterol) had more condensed domains than comparable 16:0-SM bilayers, as evidenced from the quenching resistance of DPH in DHSM membranes. We conclude that cholesterol interacts more favorably with 16:0-DHSM and that the membranes are more condensed than comparable 16:0-SM-containing membranes
Porphyromonas gingivalis may interfere with conception in women
In this observational and prospective study, we investigated if microbiological and serological markers of periodontitis associated with conception in 256 non-pregnant women (Mage = 29.2 years; range 19-42 years). Clinical oral and gynecological examinations were performed, major periodontal pathogens in the saliva were detected, and serum and saliva antibodies against major periodontal pathogens were analyzed. The follow-up period for becoming pregnant was 12 months. Porphyromonas gingivalis was significantly (p = 0.032) more frequently detected in the saliva among those who did not become pregnant (8.3%) than among those who became pregnant (2.1%). The median levels of salivary P. gingivalis immunoglobulin A (IgA; p = 0.006) and IgG (p = 0.007) antibodies were higher among those who did not become pregnant compared to those who became pregnant. Hazard ratios (HR) for not becoming pregnant were HR = 3.75 (95% confidence interval [CI] 1.01-13.9; p = 0.048) if the subject was polymerase chain reaction-positive for P. gingivalis with high salivary antibodies against it, and HR = 1.62 (95% CI 1.03-2.54; p = 0.035) if she had high levels of serum P. gingivalis IgA and signs of periodontal infection. P. gingivalis associated with no success in getting pregnant.Peer reviewe
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