Use of elastic stability analysis to explain the stress-dependent nature of soil strength

The peak and critical state strengths of sands are linearly related to the stress level, just as the frictional resistance to sliding along an interface is related to the normal force. The analogy with frictional sliding has led to the use of a ‘friction angle’ to describe the relationship between strength and stress for soils. The term ‘friction angle’ implies that the underlying mechanism is frictional resistance at the particle contacts. However, experiments and discrete element simulations indicate that the material friction angle is not simply related to the friction angle at the particle contacts. Experiments and particle-scale simulations of model sands have also revealed the presence of strong force chains, aligned with the major principal stress. Buckling of these strong force chains has been proposed as an alternative to the frictional-sliding failure mechanism. Here, using an idealized abstraction of a strong force chain, the resistance is shown to be linearly proportional to the magnitude of the lateral forces supporting the force chain. Considering a triaxial stress state, and drawing an analogy between the lateral forces and the confining pressure in a triaxial test, a linear relationship between stress level and strength is seen to emerge from the failure-by-buckling hypothesis

Understanding the illiberal turn: democratic backsliding in the Czech Republic

Democratic backsliding in Central Europe has so far been most acute in Hungary and Poland, states once considered frontrunners in democratisation. In this paper, we explore to what extent developments in another key frontrunner, the Czech Republic, fit initial patterns of Hungarian/Polish backsliding. Our analysis centres on the populist anti-corruption ANO movement, led by the billionaire Andrej Babiš, which became the largest Czech party in October 2017 after winning parliamentary elections. We find that while ANO has more limited electoral support than illiberal governing parties in Poland and Hungary and lacks a powerful nationalist narrative, common tactics and forms of concentrating power can be identified, albeit with crucial differences of timing and sequencing

Aromatherapy: Using essential oils to decrease nausea and vomiting in patients in the acute care setting

https://digitalcommons.psjhealth.org/stvincent-bootcamp/1017/thumbnail.jp

Regenerating Nucleus Pulposus of the Intervertebral Disc Using Biodegradable Nanofibrous Polymer Scaffolds

Low back pain is a leading health problem in the United States, which is most often resulted from nucleus pulposus (NP) degeneration. To date, the replacement of degenerated NP relies entirely on mechanical devices. However, a biological NP replacement implant is more desirable. Here, we report the regeneration of NP tissue using a biodegradable nanofibrous (NF) scaffold. Rabbit NP cells were seeded on the NF scaffolds to regenerate NP-like tissue both in vitro and in a subcutaneous implantation model. The NP cells on the NF scaffolds proliferated faster than those on control solid-walled (SW) scaffolds in vitro. Significantly more extracellular matrix (ECM) production (glycosaminoglycan and type II collagen) was found on the NF scaffolds than on the control SW scaffolds. The constructs were then implanted in the caudal spine of athymic rats for up to 12 weeks. The tissue-engineered NP could survive, produce functional ECM, remain in place, and maintain the disc height, which is similar to the native NP tissue.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98480/1/ten%2Etea%2E2011%2E0747.pd

Facilitators and barriers to co-research by people with dementia and academic researchers: findings from a qualitative study

Background Public and patient involvement (PPI) is now established in dementia research. Barriers and facilitators to engagement from family carers and people in early stages of dementia have been explored. However, specific barriers and facilitators to co‐research with people with dementia have not previously been investigated. Objective To discover the facilitators of, and barriers to, involving people with dementia as co‐researchers, from the perspectives of people with dementia, gatekeepers (family caregivers, ethics committee members, service providers) and researchers. Design Thematic analysis of data from individual interviews about the co‐research experience. Results Four themes emerged from interviews with 19 participants (five people with dementia): “getting one's head round it” (assumptions about research and dementia; different forms of language); practicalities (eg transport; accessibility of communication); “this feeling of safety” (perceptions of danger, protectiveness and opportunities for building trust); and motivations (“making a difference” and “keeping doing”). Conclusions Findings both replicate and extend previous knowledge on PPI in dementia. Cognitive capacity of potential co‐researchers with dementia is only a part of the picture, with attitudes and expectations of researchers, gatekeepers and people with dementia also forming barriers. Researcher education, adequate resourcing, and both creativity and flexibility are needed to support recruitment of co‐researchers with dementia and to enable meaningful co‐research

Optical absorption in boron clusters B6_{6} and B6+_{6}^{+} : A first principles configuration interaction approach

The linear optical absorption spectra in neutral boron cluster B$_{6}$ and cationic B$_{6}^{+}$ are calculated using a first principles correlated electron approach. The geometries of several low-lying isomers of these clusters were optimized at the coupled-cluster singles doubles (CCSD) level of theory. With these optimized ground-state geometries, excited states of different isomers were computed using the singles configuration-interaction (SCI) approach. The many body wavefunctions of various excited states have been analysed and the nature of optical excitation involved are found to be of collective, plasmonic type.Comment: 22 pages, 38 figures. An invited article submitted to European Physical Journal D. This work was presented in the International Symposium on Small Particles and Inorganic Clusters - XVI, held in Leuven, Belgiu

A novel bioactive derivative of eicosapentaenoic acid (EPA) suppresses intestinal tumor development in ApcΔ14/+ mice

Familial adenomatous polyposis (FAP) is a genetic disorder characterized by the development of hundreds of polyps throughout the colon. Without prophylactic colectomy, most individuals with FAP develop colorectal cancer at an early age. Treatment with EPA in the free fatty acid form (EPA-FFA) has been shown to reduce polyp burden in FAP patients. Since high-purity EPA-FFA is subject to rapid oxidation, a stable form of EPA compound has been developed in the form of magnesium l-lysinate bis-eicosapentaenoate (TP-252). We assessed the chemopreventive efficacy of TP-252 on intestinal tumor formation using ApcΔ14/+ mice and compared it with EPA-FFA. TP-252 was supplemented in a modified AIN-93G diet at 1, 2 or 4% and EPA-FFA at 2.5% by weight and administered to mice for 11 weeks. We found that administration of TP-252 significantly reduced tumor number and size in the small intestine and colon in a dose-related manner and as effectively as EPA-FFA. To gain further insight into the cancer protection afforded to the colon, we performed a comprehensive lipidomic analysis of total fatty acid composition and eicosanoid metabolites. Treatment with TP-252 significantly decreased the levels of arachidonic acid (AA) and increased EPA concentrations within the colonic mucosa. Furthermore, a classification and regression tree (CART) analysis revealed that a subset of fatty acids, including EPA and docosahexaenoic acid (DHA), and their downstream metabolites, including PGE3 and 14-hydroxy-docosahexaenoic acid (HDoHE), were strongly associated with antineoplastic activity. These results indicate that TP-252 warrants further clinical development as a potential strategy for delaying colectomy in adolescent FAP patients