Developments in liquid-crystalline dimers and oligomers

Liquid-crystalline dimers and bimesogens have attracted much attention due to their propensity to exhibit the spontaneously chiral twist-bend mesophase (NTB), most often by dimers with methylene spacers. Despite their relative ease of synthesis, the number of ether-linked twist-bend materials significantly lags behind those of methylene-linked compounds. In this work, we have prepared and studied a range of ether-linked bimesogens homologous in structure to the FFO9OCB; as with methylene-linked systems, it appears that it is molecular topology and the gross molecular shape that are the primary drivers for the formation of this phase of matter. Dimers and bimesogens are well studied within the context of the twist-bend phase; however, present understanding of this mesophase in oligomeric systems lags far behind. We report our recent efforts to prepare further examples of oligomeric twist-bend nematogens, including further examples of our ‘n+1’ methodology, which may allow the synthesis of high-purity, monodisperse materials of any given length to be prepared. We have observed that there is a tendency for these materials to exhibit highly ordered soft-crystalline mesophases as opposed to the twist-bend phase

Ecological Studies of Wolves on Isle Royale, 1981-1982

Annual Report 1981-1982 (Covering the twenty-fourth year of research)https://digitalcommons.mtu.edu/wolf-annualreports/1039/thumbnail.jp

Coupled wake boundary layer model of wind-farms

We present and test the coupled wake boundary layer (CWBL) model that describes the distribution of the power output in a wind-farm. The model couples the traditional, industry-standard wake model approach with a "top-down" model for the overall wind-farm boundary layer structure. This wake model captures the effect of turbine positioning, while the "top-down" portion of the model adds the interactions between the wind-turbine wakes and the atmospheric boundary layer. Each portion of the model requires specification of a parameter that is not known a-priori. For the wake model, the wake expansion coefficient is required, while the "top-down" model requires an effective spanwise turbine spacing within which the model's momentum balance is relevant. The wake expansion coefficient is obtained by matching the predicted mean velocity at the turbine from both approaches, while the effective spanwise turbine spacing depends on turbine positioning and thus can be determined from the wake model. Coupling of the constitutive components of the CWBL model is achieved by iterating these parameters until convergence is reached. We illustrate the performance of the model by applying it to both developing wind-farms including entrance effects and to fully developed (deep-array) conditions. Comparisons of the CWBL model predictions with results from a suite of large eddy simulations (LES) shows that the model closely represents the results obtained in these high-fidelity numerical simulations. A comparison with measured power degradation at the Horns Rev and Nysted wind-farms shows that the model can also be successfully applied to real wind-farms.Comment: 25 pages, 21 figures, submitted to Journal of Renewable and Sustainable Energy on July 18, 201

Testing the impact of an educational intervention designed to promote ocular health among people with age-related macular degeneration

Research has shown that individuals affected by age-related macular degeneration (AMD) do not always consume foods or supplements known to be beneficial for ocular health. This study tested the effectiveness of an educational intervention designed to promote healthy eating and nutritional supplementation in this group. A total of 100 individuals with AMD completed baseline measures of several variables: confidence that diet affects AMD, motivation to engage in health-protective behaviours, knowledge about which nutrients are beneficial, and intake of kale, spinach, and eggs. Participants were allocated to either intervention or control conditions. Intervention participants received a leaflet and prompt card that contained advice regarding dietary modification and supplementation. Control participants received a leaflet created by the Royal College of Optometrists. A follow-up questionnaire, measuring the same variables assessed at baseline, was administered 2 weeks later. At follow-up, significant condition × time interactions were found for confidence that diet affects AMD (F(1, 92) = 4.54, p < .05), motivation to talk to an eye professional about supplementation (F(1, 92) = 4.53, p = .036), motivation to eat eggs (F(1, 92) = 12.67, p = .001), and egg intake (F(1, 92) = 11.97, p = .001). In each case, intervention participants scored higher than control participants. Receiving an educational intervention increased participants’ confidence that diet affects AMD, motivation to engage in health-protective behaviours, and egg intake. This intervention could be easily incorporated into current clinical practice delivered by either optometrists or ophthalmologists

The association between restricted activity and patient outcomes in older adults: systematic literature review and meta-analysis

Background: Restricted activity is a potential early marker of declining health in older adults. Previous studies of this association with patient outcomes have been inconclusive. This review aimed to evaluate the extent to which restricted activity is associated with decline in health. Methods: A search was conducted for studies including people over 65 years old which investigated the association between measures of restricted activity and hospitalisation, cognitive decline, and mortality. Following data extraction by two reviewers, eligible studies were summarised using Inverse Variance Heterogeneity meta-analysis. Results: The search identified 8,434 unique publications, with 11 eligible studies. Three measures of restricted activity were identified: bed rest, restricted movement, and dependency for activities of daily living (ADL). Three studies looked at hospitalisations, with two finding a significant association with bed rest or restricted movement and one showing no evidence of an association. Restricted activity was associated with a significant increase in mortality across all three measures (bed rest odds ratio [OR] 6.34, 95%CI 2.51–16.02, I2 = 76%; restricted movement OR 5.38 95%CI 2.60–11.13, I2 = 69%; general ADL dependency OR 4.65 95%CI 2.25–9.26, I2 = 84%). The significant heterogeneity observed could not be explained by restricting the analysis by length of follow-up, or measure of restricted activity. No meta-analysis was conducted on the limited evidence for cognitive decline outcomes. Conclusions: Limited studies have considered the prognostic value of restricted activity in terms of predicting future declining health. Current evidence suggests restricted activity is associated with hospitalisation and mortality, and therefore could identify a group for whom early intervention might be possible

Adverse health effects of nighttime lighting: comments on american medical association policy statement.

The American Medical Association House of Delegates in June of 2012 adopted a policy statement on nighttime lighting and human health. This major policy statement summarizes the scientific evidence that nighttime electric light can disrupt circadian rhythms in humans and documents the rapidly advancing understanding from basic science of how disruption of circadian rhythmicity affects aspects of physiology with direct links to human health, such as cell cycle regulation, DNA damage response, and metabolism. The human evidence is also accumulating, with the strongest epidemiologic support for a link of circadian disruption from light at night to breast cancer. There are practical implications of the basic and epidemiologic science in the form of advancing lighting technologies that better accommodate human circadian rhythmicity

Global transcriptional profiling of Burkholderia pseudomallei under salt stress reveals differential effects on the Bsa type III secretion system

BACKGROUND: Burkholderia pseudomallei is the causative agent of melioidosis where the highest reported incidence world wide is in the Northeast of Thailand, where saline soil and water are prevalent. Moreover, recent reports indicate a potential pathogenic role for B. pseudomallei in cystic fibrosis lung disease, where an increased sodium chloride (NaCl) concentration in airway surface liquid has been proposed. These observations raise the possibility that high salinity may represent a favorable niche for B. pseudomallei. We therefore investigated the global transcriptional response of B. pseudomallei to increased salinity using microarray analysis. RESULTS: Transcriptome analysis of B. pseudomallei under salt stress revealed several genes significantly up-regulated in the presence of 320 mM NaCl including genes associated with the bsa-derived Type III secretion system (T3SS). Microarray data were verified by reverse transcriptase-polymerase chain reactions (RT-PCR). Western blot analysis confirmed the increased expression and secretion of the invasion-associated type III secreted proteins BipD and BopE in B. pseudomallei cultures at 170 and 320 mM NaCl relative to salt-free medium. Furthermore, salt-treated B. pseudomallei exhibited greater invasion efficiency into the lung epithelial cell line A549 in a manner partly dependent on a functional Bsa system. CONCLUSIONS: B. pseudomallei responds to salt stress by modulating the transcription of a relatively small set of genes, among which is the bsa locus associated with invasion and virulence. Expression and secretion of Bsa-secreted proteins was elevated in the presence of exogenous salt and the invasion efficiency was enhanced. Our data indicate that salinity has the potential to influence the virulence of B. pseudomallei

Immunization with the C-domain of α-toxin prevents lethal infection, localizes tissue injury, and promotes host response to challenge with Clostridium perfringens

© 2004 by the Infectious Diseases Society of America. All rights reserved.Clostridium perfringens gas gangrene is characterized by rapid tissue destruction, impaired host response, and, often, death. Phospholipase C (α-toxin) is the virulence factor most responsible for these pathologies. The present study investigated the efficacy of active immunization with the C-terminal domain of α-toxin (Cpa247–370) in a murine model of gas gangrene. Primary end points of the study were survival, progression of infection, and tissue perfusion. Secondary end points, which were based on findings of histologic evaluation of tissues, included the extent of tissue destruction and microvascular thrombosis, as well as the magnitude of the tissue inflammatory response. Survival among C-domain–immunized animals was significantly greater than that among sham-immunized control animals. Furthermore, immunization with the C-domain localized the infection and prevented ischemia of the feet. Histopathologic findings demonstrated limited muscle necrosis, reduced microvascular thrombosis, and enhanced granulocytic influx in C-domain–immunized mice. We conclude that immunization with the C-domain of phospholipase C is a viable strategy for the prevention of morbidity and mortality associated with C. perfringens gas gangrene

Functional redundancy of Burkholderia pseudomallei phospholipase C enzymes and their role in virulence

This is the final version. Available on open access from Nature Research via the DOI in this recordPhospholipase C (PLC) enzymes are key virulence factors in several pathogenic bacteria. Burkholderia pseudomallei, the causative agent of melioidosis, possesses at least three plc genes (plc1, plc2 and plc3). We found that in culture medium plc1 gene expression increased with increasing pH, whilst expression of the plc3 gene was pH (4.5 to 9.0) independent. Expression of the plc2 gene was not detected in culture medium. All three plc genes were expressed during macrophage infection by B. pseudomallei K96243. Comparing B. pseudomallei wild-type with plc mutants revealed that plc2, plc12 or plc123 mutants showed reduced intracellular survival in macrophages and reduced plaque formation in HeLa cells. However, plc1 or plc3 mutants showed no significant differences in plaque formation compared to wild-type bacteria. These findings suggest that Plc2, but not Plc1 or Plc3 are required for infection of host cells. In Galleria mellonella, plc1, plc2 or plc3 mutants were not attenuated compared to the wild-type strain, but multiple plc mutants showed reduced virulence. These findings indicate functional redundancy of the B. pseudomallei phospholipases in virulence.Mahidol UniversityThailand Research Fun