Far-infrared optical properties and molecular interactions

The far-infrared absorption spectra of solutions of tetra-n-alkylammonium salts have been studied in benzene, chloroform, carbon tetrachloride and tetrahydrofuran, as a function of concentration, temperature, solute and solvent. The absorption profile has been computer fitted to the sum of 3 component bands, and the variation of band centre, half-band width, area and intensity with concentration, temperature, solute and solvent has been studied. The spectral features, and their variation with the parameters above, have been shown to be consistent with the absorptions arising from ion-ion vibrations, ion aggregate 'librational' absorptions and fluctuating electrical fields, due to 'effective' dipole-induced dipole interactions. The observed intensities were seen to be reproduced for model geometries and effective aggregate dipoles, which agreed well with those obtained from dielectric relaxation measurements. It was concluded that the higher degree of ion-clustering in the solutions leads to severe restrictions on the movement of both solute and solvent species. It is proposed that some solvent molecules may be trapped within the ionic cluster. The absorptions of more polar systems have been compared with the non-polar systems. Computer programmes have been developed to compute refractive index data from interferograms obtained with a Michelson interferometer operated in the dispersive mode. The experimental and computational procedures have been tested by determining the refractive index of polytetrafluoroethylene sheets in the far-infrared. Methods for the computation of intensities from refractive index values have been developed, and the intensities for the 202 cm(^-1) band of polytetrafuoroethylene obtained by both dispersive and non-dispersive methods have been compared. A cell has been designed, constructed and tested, which can be used to measure the refractive index of liquids and solutions in the far-infrared region. This cell has been incorporated into a Beckman-RIIC Ltd. FS-720 interferometer, as an extra (dispersive) module

"What have the Romans ever done for us?" Academic and activist forms of movement theorizing

We want to pose some questions about the relationship between social movements and 'social movement theories'. The questions reflect the sense of unease experienced by some 'academic intellectuals' who are also activists in movements, and the scepticism sometimes expressed by activists about the value of 'social movement theory.' Both of us having a foot in each camp, we share the unease

How Should a ‘Sustainable Corporation’ Account for Natural Capital?

Corporate activity promotes economic growth. This has obvious benefits for society, yet by placing unsustainable demands on natural resources, it also poses serious problems. Part of the response to this should be clarity over corporate responsibility and accountability towards the environment, including in regard to the design and implementation of an appropriate system of accounting. In this paper we propose a reinterpretation of financial accounting in which it is argued that existing systems should not be viewed as independent of natural capital accounting; instead, financial accounting should be extended to record profit as a surplus with respect to financial capital once physical capital maintenance of (critical) natural capital has been recorded. Such an approach draws a clean distinction between stocks and flows that are financially and sustainability relevant, while incorporating both within an integrated accounting system. This mitigates the tension that conventionally exists between corporate responsibility towards shareholders and stakeholders

Modeling HIV-1 Infection in the Brain: The Effect of the Blood-Brain Barrier

Title from PDF of title page viewed May 27, 2020Dissertation advisor: Naveen VaidyaVitaIncludes bibliographical references (pages 100-110)Thesis (Ph.D.)--Department of Mathematics and Statistics and Department of Physics and Astronomy. University of Missouri--Kansas City, 2020Despite the advancement of antiretroviral therapy (ART), the development of HIV associated neurocognitive disorders (HAND) remains a major concern among HIV infected patients. As many ART drugs may fail to penetrate the blood-brain barrier (BBB), the long-term presence of viral RNA in the brain is considered to be associated with these disorders, such as early-onset dementia. \textit{In vivo} study of HIV infection in the brain is extremely difficult, and thus mathematical modeling can help to further the analysis of the viral dynamics of HIV in the brain. In this dissertation we develop a mathematical model to help investigate the viral dynamics of HIV in the brain. Our model can explain containing viral loads in the plasma and in the cerebral spinal fluid from SIV-infected macaques. We then extend this model to study the treatment of HIV in the brain. Furthermore we develop a new stochastic model to analyze any stochastic effects that may underlie HIV-viral dynamics in the brain. Using our models, we show that the rate of transport of infected macrophages into the brain greatly exceeds the rate of transport out of the brain. We also show that viral replication occurs in the brain, suggesting that the brain can act as a viral reservoir. We also show that the basic reproduction number largely depends on the overall effectiveness of ART, but it is not strongly affected by the rate of drug penetration through the blood-brain barrier. The effectiveness of ART depends on both pharmacodynamic parameters and a drug's ability to penetrate through the BBB. In particular, for drugs with a high dose-response curve, the BBB penetration strongly affects the post-treatment control of the virus in the brain. Through examination of the stochastic model we illustrate a prolonged higher likelihood of infection and viral production in the brain compared to the plasma. Results in this dissertation may be useful to develop HIV control strategies to target the virus hiding in the brain.Introduction -- Background information -- Modeling the role of the BBB on the HIV dynamics in the brain -- Effects of the blood-brain barrier on the treatment of HIV-Infection in the brain -- Stochastic model of HIV infection in the brain -- Conclusions and discussio

Cryptic introgression into the kidney saxifrage (Saxifraga hirsuta) from its more abundant sympatric congener Saxifraga spathularis, and the potential risk of genetic assimilation

Background and Aims Although hybridization can play a positive role in plant evolution, it has been shown that excessive unidirectional hybridization can result in replacement of a species’ gene pool, and even the extinction of rare species via genetic assimilation. This study examines levels of introgression between the common Saxifraga spathularis and its rarer congener S. hirsuta, which have been observed to hybridize in the wild where they occur sympatrically. Methods Seven species-specific single nucleotide polymorphisms (SNPs) were analysed in 1025 plants representing both species and their hybrid, S. × polita, from 29 sites across their ranges in Ireland. In addition, species distribution modelling was carried out to determine whether the relative abundance of the two parental species is likely to change under future climate scenarios. Key Results Saxifraga spathularis individuals tended to be genetically pure, exhibiting little or no introgression from S. hirsuta, but significant levels of introgression of S. spathularis alleles into S. hirsuta were observed, indicating that populations exhibiting S. hirsuta morphology are more like a hybrid swarm, consisting of backcrosses and F(2)s. Populations of the hybrid, S. × polita, were generally comprised of F(1)s or F(2)s, with some evidence of backcrossing. Species distribution modelling under projected future climate scenarios indicated an increase in suitable habitats for both parental species. Conclusions Levels of introgression observed in this study in both S. spathularis and S. hirsuta would appear to be correlated with the relative abundance of the species. Significant introgression of S. spathularis alleles was detected in the majority of the S. hirsuta populations analysed and, consequently, ongoing introgression would appear to represent a threat to the genetic integrity of S. hirsuta, particularly in areas where the species exists sympatrically with its congener and where it is greatly outnumbered

Kant on Modality

This chapter analyzes several key themes in Kant’s views about modality. We begin with the pre-critical Only Possible Argument in Support of a Demonstration of the Existence of God, in which Kant distinguishes between formal and material elements of possibility, claims that all possibility requires an actual ground, and argues for the existence of a single necessary being. We then briefly consider how Kant’s views change in his mature period, especially concerning the role of form and thought in defining modality. Kant’s mature views, however, present two difficult interpretive puzzles. The first puzzle concerns whether Kant has a generally reductive view of modality. While Kant’s views on logical modality, the role of actuality in grounding possibility, and the relation of modality to cognition all suggest reduction, we argue that the categorial status of modal concepts and the difficulty in even identifying amodal grounds for modal facts all suggest a non-reductive view. The second puzzle concerns whether Kant accepts modal facts or properties at the noumenal level. While Kant’s appeal to noumenal necessary connections, the contingency of noumenal willing, and the idea of a necessary noumenal being suggest that he endorses noumenal modality, his claims that modal concepts express only relations to the faculty of cognition and his claim that modal concepts arise from our distinctive psychological structures, we argue, suggest that he rejects noumenal modality. We conclude by considering potential solutions to these puzzles

Contemporary Management of Secondary Mitral Regurgitation

Secondary mitral regurgitation (SMR) is a common occurrence in patients with heart failure with reduced ejection fraction. Moderate-severe or severe SMR is associated with increased mortality and hospitalisations from heart failure. Medical and cardiac resynchronisation therapies have been the only treatments proven to improve prognosis in this patient population. The Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy (COAPT) and the Percutaneous Repair with the MitraClip Device for Severe Functional/Secondary Mitral Regurgitation (MITRA-FR) RCTs evaluated transcatheter mitral valve repair with MitraClip for treatment of SMR in addition to medical therapy and they had divergent results. The COAPT trial demonstrated that a reduction in SMR with MitraClip resulted in reduced mortality and heart failure hospitalisations along with improved symptoms and quality of life in appropriately selected patients. The MITRA-FR trial did not show any benefit from using MitraClip for patients with SMR. This article summarises the differences in these two trials and suggests a contemporary approach to the management of SMR

Don’t turn your back on the symptoms of psychosis : the results of a proof-of-principle, quasi-experimental intervention to reduce duration of untreated psychosis

Background No evidence based approach to reduce duration of untreated psychosis (DUP) has been effective in the UK. Existing interventions have many components and have been difficult to replicate. The majority of DUP in Birmingham, UK is accounted for by delays within mental health services (MHS) followed by help-seeking delay and, we hypothesise, these require explicit targeting. This study examined the feasibility and impact of an intervention to reduce DUP, targeting help-seeking and MHSs delays. Methods A dual-component intervention, comprising a direct care pathway, for 16-25 year olds, and a community psychosis awareness campaign, using our youth-friendly website as the central hub, was implemented, targeting the primary sources of care pathway delays experienced by those with long DUP. Evaluation, using a quasi-experimental, design compared DUP of cases in two areas of the city receiving early detection vs detection as usual, controlling for baseline DUP in each area. Results DUP in the intervention area was reduced from a median 71 days (mean 285) to 39 days (mean 104) following the intervention, with no change in the control area. Relative risk for the reduction in DUP was 0.74 (95 % CI 0.35 to 0.89; p = .004). Delays in MHSs and help-seeking were also reduced. Conclusions Our targeted approach appears to be successful in reducing DUP and could provide a generalizable methodology applicable in a variety of healthcare contexts with differing sources of delay. More research is needed, however, to establish whether our approach is truly effective