A Spatial Analysis of Streambank Heterogeneity and its Contribution to Bank Stability

Streambank erosion is a function of fluvial detachment and geotechnical failure mechanisms working in combination to cause bank retreat. It is generally agreed that bank stability is dependent on both types of erosion; however, few studies have attempted to correlate the driving and resisting forces between the two. It has been proposed that: (1) streambanks possess a spatial structure and dependence of non-erodible resistant structures such as root masses and rocks; (2) streambanks naturally “armor” themselves from fluvial erosion with a combination of hard points and resistive soil; and (3) the stability of the streambank can be predicted by the amount of composite fluvial resistance, thereby connecting fluvial resistance and geotechnical stability. These hypotheses were tested through extensive field analysis, spatial statistical methods, and multivariate statistics. Eighteen streambanks sites with cohesive sediment structures in the Eastern Tennessee Ridge and Valley Ecoregion were sampled for in-situ erodibility and critical shear stress as well as the spatial distribution of nonerodible hard points. Using a combination of nearest neighbor, join count, and indicator variogram statistics it was discovered that streambanks in this region possess natural clusters of these non-erodible structures. However, the study was unsuccessful in determining the cause of spatial dependency of non-erodible clusters between various banks, as not all banks exhibit this quality. Multiple linear regression was utilized to compare all streambanks, with the results indicating that the density of these clustered hard points displays a positive linear relationship with the critical shear strength of the surrounding soil matrix, suggesting a coordination between the two and possible natural armoring of the composite bank structure. Additionally, the USDA Bank Stability and Toe Erosion Model (BSTEM) was utilized to determine the relative stability of these streambanks. With this information, both discriminate analysis and multiple linear regression were applied to determine that stable streambanks are controlled by a combination of the respective stream power, average soil critical shear strength, standard deviation of the critical shear strength, bank height, and cluster density of non-erodible structures. This information helped derive relevant interactions for stable stream bank analysis including possible stream restoration and site investigation applications

The reasons for the rise and fall of Bearer Shares: a company law comparison between the UK and some offshore jurisdictions

Moving forward for the need for more transparency, the United Kingdom has also established a Beneficial Ownership Register which publicly accessible while the offshore financial centres have refused. Many Offshore Financial Centres are moving toward controlling Bearer Shares in order to keep in line with the Organization for Economic and Cooperative Development’s push for more transparency. As of 2015, the United Kingdom has altered its Company Law and has totally abolished Bearer Shares. However, Offshore Financial Centres such as The Cayman Islands through now immobilised, The British Virgin Islands and more recently the Republic of Panama have found an innovative solution through the immobilisation of bearer shares to protect privacy while still managing to control illegal activities. Over all with the abolishing of bearer shares and the new beneficial ownership register the United Kingdom is moving towards Greater transparency

Point-Counterpoint: Value of School Textbooks

Educators frequently are involved in textbook adoptions in various content areas, an important activity because textbook programs may define school curricula by dictating what is taught, in what sequence, and for how long. Recently, education groups have criticized school textbooks for being boring, incoherent, and dumbed-down. Viewed from one perspective the selection of new textbooks offers little hope for improving the school reading program because by their nature textbooks can inhibit the teaching of thinking. Viewed from a different perspective, textbooks offer the potential for much improvement in the reading program, if features of the text are used to the fullest with a critical approach. Educators looking to improve the reading programs in their schools may reasonably ask, What are the positive and negative values of using textbooks? This point-counterpoint discussion focuses on four issues involved in answering that question

Continuous epidural infusion of morphine versus single epidural injection of extended-release morphine for postoperative pain control after arthroplasty: a retrospective analysis

Stephanie Vanterpool, Randall Coombs, Karamarie FechoDepartment of Anesthesiology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USABackground: This study retrospectively compared the continuous epidural infusion of morphine with a single epidural injection of extended-release morphine for postoperative pain control after arthroplasty.Methods: Medical records were reviewed for subjects who had total knee or hip arthroplasty (THA) under spinal anesthesia and received either a continuous epidural infusion of morphine (Group EPID; n = 101) or an extended-release epidural morphine (Group EREM; n = 109) for postoperative pain. Data were collected for three postoperative days (POD) on: pain scores; supplemental opioids; medications for respiratory depression, nausea, and pruritus, and distance ambulated during physical therapy.Results: Pain scores were similar until subjects were transitioned to another analgesic approach on POD 2; after that time, pain scores increased in Group EPID, although they decreased in Group EREM. Supplemental opioids were used more on POD1 in Group EREM than in Group EPID, although time to first opioid and total daily morphine equivalents were similar. Naloxone and antiemetics, not antipruritics, were used more in Group EREM. Distance ambulated after THA was greater in Group EREM than in Group EPID.Conclusions: These results suggest that EREM is associated with better postoperative ambulation and analgesia during the transition to oral or intravenous analgesics, although a higher incidence of side-effects was evident.Keywords: continuous epidural morphine infusion, extended-release epidural morphine, lower extremity arthroplasty, ambulation, postoperative pain, side-effect

Deconstructing the tumour microenvironment: the role of fibronectin

Cancer is a worldwide issue affecting millions and the need for understanding specific mechanisms linked to its progression has never been higher. One of the biggest challenges in cancer research is the complexity of the tumour microenvironment (TME) which not only consists of cancerous cells, but auxiliary lymphocytes, macrophages, blood vessels and the extracellular matrix (ECM). There is therefore a need to unravel the impact of these specific components on cancer cells by deconstructing their environment. In this study, we aim to understand fundamental cell-ECM interactions by breaking down the complex TME to its building blocks: the cancer cell and the ECM. We use poly(alkyl acrylates) material surfaces which have been shown to direct the organisation of fibronectin (FN), a key ECM protein, upon adsorption to study cell behaviour such as adhesion, growth, migration and drug resistance. Here we show that poly(methyl acrylate) (PMA) and poly(ethyl acrylate) PEA are able to organise FN into globular and fibrillar conformations respectively upon adsorption, thus exposing or concealing specific integrin binding domains such as the RGD cell binding domain and the PHSRN synergy sequence. With these conditions, we assess: cell adhesion through studying attachment, focal adhesion formation and single cell traction on the surface of the polymers; cell migration by looking at the speed of gap closure in wound healing assays; drug resistance by studying cytotoxicity of a well-established anticancer drug in docetaxel as well as PND-1186 (VS-4718) which is a novel drug currently in phase 1 clinical trials; and intracellular signalling by quantifying protein expressions of focal adhesion kinase (FAK). Furthermore, we conduct a preliminary study of cancer cells in a highly tuneable PEG-based (poly ethylene glycol) 3D system functionalised with the RGD cell binding domain. We analyse hydrogel stability, cell viability and cell invasion. We demonstrate that upon adsorption to the polymers the fibrillar and globular forms of FN lead to the PHSRN synergy sequence being more exposed on PEA compared to PMA respectively. This is shown to have significant impact on cell anchorage, mediated primarily by the RDG domain of FN via integrin αvβ3, and cell motility which is mediated by both the RGD and PHSRN sequences via integrin α5β1. We also demonstrate that although this 2D model provides essential information for cell-ECM interactions, it does not take into account the 3D environment. We show that cells are able to interact with the proposed PEG-based hydrogel and that it can be fine-tuned by altering gel stiffness and functional components independently. Overall, the methods and systems used in this study have allowed for a better understanding of the material-protein and the cell-protein interfaces and how they affect cell behaviour in regard to adhesion, migration and invasion

Combustion Synthesis And Characterization Of Porous Niti Intermetallic For Structural Application

This thesis describes experimental investigation of thermal and combustion phenomena as well as structure for self- propagating combustion synthesis of porous Ni - Ti intermetallic aimed for structural biomedical application. The control parameters for the porosity distribution have been investigated experimentally through varying the preheat temperature, initial porosity, initial elemental particle size, and applied pressure during the fabrication process. Ni and Ti elemental powders are mixed using a 1:1 ratio. The mixture is compressed using several different compression forces to produce cylindrical samples of 1.1 cm diameter and 2-3cm length, with initial porosity ranging from 30% to 40%. The samples are preheated to various initial temperatures and ignited from the top surface such that the flame propagates axially downwards. The combustion reaction is recorded with a motion camera. An infrared sensor is used to record the temperature profile during the combustion process. The samples are then cut using a diamond saw in both longitudinal and transverse directions. Image analysis software is then used to analyze the porosity distribution in each sample

Biocompatible chitosan-functionalized upconverting nanocomposites

Simultaneous integration of photon emission and biocompatibility into nanoparticles is an interesting strategy to develop applications of advanced optical materials. In this work, we present the synthesis of biocompatible optical nanocomposites from the combination of near-infrared luminescent lanthanide nanoparticles and water-soluble chitosan. NaYF4:Yb,Er upconverting nanocrystal guests and water-soluble chitosan hosts are prepared and integrated together into biofunctional optical composites. The control of aqueous dissolution, gelation, assembly, and drying of NaYF4:Yb,Er nanocolloids and chitosan liquids allowed us to design novel optical structures of spongelike aerogels and beadlike microspheres. Well-defined shape and near-infrared response lead upconverting nanocrystals to serve as photon converters to couple with plasmonic gold (Au) nanoparticles. Biocompatible chitosan-stabilized Au/NaYF4:Yb,Er nanocomposites are prepared to show their potential use in biomedicine as we find them exhibiting a half-maximal effective concentration (EC50) of 0.58 mg mL–1 for chitosan-stabilized Au/NaYF4:Yb,Er nanorods versus 0.24 mg mL–1 for chitosan-stabilized NaYF4:Yb,Er after 24 h. As a result of their low cytotoxicity and upconverting response, these novel materials hold promise to be interesting for biomedicine, analytical sensing, and other applications