Stick and Slip Behaviour of Confined Oligomer Melts under Shear. A Molecular-Dynamics Study.

The flow behaviour of melts of short chains, confined in molecularly thin Couette flow geometries, is studied with molecular-dynamics simulations. The effect of wall attraction and confinement on the density and velocity profiles is analysed. In these highly inhomogeneous films, a strong correlation between the density and velocity profile is found. Sticking of the interfacial layer on the wall and slip on the wall and inside the film is manifested by changes in the velocity profile. The location of the slip is determined by the strength of the wall attraction.

Atomic Force Microscopy and Real Atomic Resolution. Simple Computer Simulations.

Using a simple computer simulation for AFM imaging in the contact mode, pictures with true and false atomic resolution are demonstrated. The surface probed consists of two f.c.c. (111) planes and an atomic vacancy is introduced in the upper layer. Changing the size of the effective tip and its registry with respect to the atoms of the crystal probed, images with completely different qualitative features are obtained. If the effective tip is a single atom the vacancy is clearly imaged. However, if the tip consists of several atoms and is in registry with the sample, a virtual atom appears instead of the vacancy and the crystal lattice is perfectly reproduced. If the tip is out of registry with respect to the sample, artifacts having the size of the effective tip are reported.

Development and evaluation of a screening tool to identify people with diabetes at increased risk of medication problems relating to hypoglycaemia and medication non-adherence

Abstract Aims: To develop and evaluate a screening tool to identify people with diabetes at increased risk of medication problems relating to hypoglycaemia and medication non-adherence. Methods: A retrospective audit of attendances at a diabetes outpatient clinic at a public, teaching hospital over a 16-month period was conducted. Logistic regression was undertaken to examine risk factors associated with medication problems relating to hypoglycaemia and medication non-adherence and the most predictive set of factors comprise the Diabetes Medication Risk Screening Tool. Evaluating the tool involved assessing sensitivity and specificity, positive and negative predictive values, cut-off scores, inter-rater reliability, and content validity. Results: The Diabetes Medication Risk Screening Tool comprises seven predictive factors: age, living alone, English language, mental and behavioural problems, comorbidity index score, number of medications prescribed, and number of high-risk medications prescribed. The tool has 76.5% sensitivity, 59.5% specificity, and has a 65.1% positive predictive value, and a 71.8% negative predictive value. A score of 27 or more out of 62 was associated with high-risk of a medication problem. The inter-rater reliability of the tool was high (κ = 0.79, 95% CI 0.75 - 0.84) and the content validity index was 99.4%. Conclusion: The Diabetes Medication Risk Screening Tool has good psychometric properties and can proactively identify people with diabetes at greatest risk of medication problems relating to hypoglycaemia and medication non-adherence

Inhomogeneities in sheared ultrathin lubricating films

Nonequilibrium molecular dynamics computer simulations have been used to study nanoscopically confined oligomer films under shear. Beyond the well-known density layering across such films, other structural and dynamical inhomogeneities exist across such films and are discussed here. When these films are subjected to strong shear flows, slip appears at the confining surfaces or inside the pore, depending on the wall interactions. For strong wall affinities interlayer slip develops between the adsorbed layer and the free chains, resulting in a structural discontinuity; a molecular mechanism, involving shear induced conformational changes of the adsorbed chains, is associated with this interlayer slip. Moreover, the resistance to flow (quantified through an effective viscosity) changes considerably across the film, with a dramatic viscosity increase of the adsorbed layer near attractive surfaces. Shear thinning is mainly taking place inside this more viscous interfacial layer, whereas the dynamics in the middle of the film remain bulklike; thus, there also exists strong inhomogeneity in the dynamics of the system. A comparison with SFA experimental and theoretical studies is also made

Effect of shear on the desorption of oligomers in nanoscopically confined films

Bitsanis et al. J. Chem. Phys. 99, 5520 (1993) found that in nanoscopically confined films between strongly physisorbing surfaces chains with many contacts with the walls are irreversibly adsorbed. When shear is imposed to these systems molecular dynamics (MD) simulations show that the majority of the adsorbed oligomers adopts flat conformations on top of the walls. Although these conformations are characterized by high molecular adsorption energies, the same MD simulations show that desorption is strongly promoted by shear. The underlying mechanism is discussed

Adsorption-desorption kinetics in nanoscopically confined oligomer films under shear

The method of molecular dynamics computer simulations is employed to study oligomer melts confined in ultra-thin films and subjected to shear. The focus is on the self-diffusion of oligomers near attractive surfaces and on their desorption, together with the effects of increasing energy of adsorption and shear. It is found that the mobility of the oligomers near an attractive surface is strongly decreased. Moreover, although shearing the system forces the chains to stretch parallel to the surfaces and thus increase the energy of adsorption per chain, flow also promotes desorption. The study of chain desorption kinetics reveals the molecular processes responsible for the enhancement of desorption under shear. They involve sequences of conformations starting with a desorbed tail and proceeding in a very fast, correlated, segment-by-segment manner to the desorption of the oligomers from the surfaces.

Using patients\u27 experiences of adverse events to improve health service delivery and practice: protocol of a data linkage study of Australian adults age 45 and above

Evidence of patients\u27 experiences is fundamental to creating effective health policy and service responses, yet is missing from our knowledge of adverse events. This protocol describes explorative research redressing this significant deficit; investigating the experiences of a large cohort of recently hospitalised patients aged 45 years and above in hospitals in New South Wales (NSW), Australia

From telling to sharing to silence: A longitudinal ethnography of professional-patient communication about oral chemotherapy for colorectal cancer.

BACKGROUND: Healthcare professionals are encouraged to promote concordance, a shared agreement about prescription and administration of medications, in their communication with patients. However, there is a paucity of research regarding the impact of communication about self-administered oral chemotherapy. The aim of this study was to examine the changing dynamics of communication through the patient journey from diagnosis of colorectal cancer to posttreatment of chemotherapy. METHODS: Over 60 hours of observational data were digitally recorded from interactions between 15 healthcare professionals, eight patients with colorectal cancer prescribed capecitabine, and 11 family members over a 6-month period in outpatient departments within one hospital in the United Kingdom. Sixteen semi-structured interviews were conducted with patients during and after their treatment. Three focus groups were carried out with healthcare professionals. These data were analysed using thematic analysis. RESULTS: The patient journey followed a path of four distinct phases: autocracy, physiological concordance, holistic concordance, and silence. Initially, communication was medicalised with patients occupying a passive role. As patients continued their journey, they took a more active role in their treatment discussion by leading consultations and sharing their priorities of care. At the end of treatment, patients felt isolated and unsupported when they were discharged from their oncology team. CONCLUSIONS: Communication about oral chemotherapy is not a static process; it evolves to take account of changing clinical requirements and growing patient confidence in dealing with their cancer. Different stages in the treatment journey indicate the need for different approaches to communication

Enabling sustained communication with patients for safe and effective management of oral chemotherapy: A longitudinal ethnography.

AIMS: To examine how patients received, understood, and acted on healthcare professional communication about their oral chemotherapeutic regimen throughout their treatment. DESIGN: A longitudinal ethnographic study. METHODS: Over 60 hr of observational data were recorded, in the form of field notes and audio-recordings from interactions among nine oncology doctors, six oncology nurses, eight patients, and 11 family members over a period of 6 months in outpatient departments in one hospital in Northern Ireland. Sixteen semi-structured interviews with patients and three focus groups with healthcare professionals were also carried out. This study took place from October 2013-June 2016. Data were thematically analysed. RESULTS: Three themes where identified from the data. These were initiating concordance through first communication about oral chemotherapy; which focused on initial communication during oncology consultations about oral chemotherapy, sustained communication of managing chemotherapy side effects; which was about how communication processes supported timely and effective side effect management and un-sustained communication of oral chemotherapy medication-taking practice; when patients and healthcare professionals failed to communicate effectively about chemotherapy medication-taking. CONCLUSION: The two most important factors in ensuring the optimal management of oral chemotherapeutic medicines are early recognition and appropriate response to side effects and the maintenance of safe and effective medication administration. This study found that oncology doctors and nurses engaged in sustained communication about the side effects of chemotherapy but did not focus their communication on safe administration after the first consultation. IMPACT: Based on this evidence, we recommend that healthcare professionals who provide oral chemotherapy for home administration should review their processes and procedures. Healthcare professionals need to ensure that they embed frequent communication for the duration of treatment between themselves and patients, including open discussion and advice, about side effects and medication administration