London force and energy transportation between interfacial surfaces

With appropriately selected optical frequencies, pulses of radiation propagating through a system of chemically distinct and organized components can produce areas of spatially selective excitation. This paper focuses on a system in which there are two absorptive components, each one represented by surface adsorbates arrayed on a pair of juxtaposed interfaces. The adsorbates are chosen to be chemically distinct from the material of the underlying surface. On promotion of any adsorbate molecule to an electronic excited state, its local electronic environment is duly modified, and its London interaction with nearest neighbor molecules becomes accommodated to the new potential energy landscape. If the absorbed energy then transfers to a neighboring adsorbate of another species, so that the latter acquires the excitation, the local electronic environment changes and compensating motion can be expected to occur. Physically, this is achieved through a mechanism of photon absorption and emission by molecular pairs, and by the engagement of resonance transfer of energy between them. This paper presents a detailed analysis of the possibility of optically effecting such modifications to the London force between neutral adsorbates, based on quantum electrodynamics (QED). Thus, a precise link is established between the transfer of excitation and ensuing mechanical effects

Barriers and facilitators to self-care in chronic heart failure: A meta-synthesis of qualitative studies

Chronic heart failure (CHF) is a costly condition that places large demands on self-care. Failure to adhere with self-care recommendations is common and associated with frequent hospitalization. Understanding the factors that enable or inhibit self-care is essential in developing effective health care interventions. This qualitative review was conducted to address the research question, "What are the barriers and facilitators to self-care among patients with CHF?" Electronic databases including Medline, EMBASE, CINAHL, Web of Science, Scopus and Google scholar were searched. Articles were included if they were peer reviewed (1995 to 2012), in English language and investigated at least one contextual or individual factor impacting on self-care in CHF patients > 18years. The criteria defined by Kuper et al. including clarity and appropriateness of sampling, data collection and data analysis were used to appraise the quality of articles. Twenty-three articles met the inclusion criteria. Factors impacting on self-care included: factors related to symptoms of CHF and the self-care process; factors related to personal characteristics; environmental and health care system factors. Important factors such as socioeconomic situation and education level have not been explored extensively and there is minimal data on the influence of age, gender, selfconfidence and duration of disease. Although there is an emerging literature, further research is required to address the barriers and facilitators of self-care in patients with CHF in order to provide an appropriate guide for intervention strategies to improve self-care in CHF. © 2013 Siabani et al

A randomized controlled trial to evaluate an educational strategy involving community health volunteers in improving self-care in patients with chronic heart failure: Rationale, design and methodology

© 2014, Siabani et al.; licensee Springer. Background: Chronic heart failure (CHF) is an increasingly important health problem worldwide. Effective self-care can improve the outcomes and quality of life in patients with CHF. Acknowledging the important role of educational interventions for improving self-care, we sought to assess a new educational strategy involving community health volunteers (CHVs) that could reduce the cost and, hypothetically, increase the effectiveness of self-care education in patients with CHF.Methods/Design: In this ongoing three-arm controlled trial, approved by two human research ethics committees in Australia and Iran, 231 patients with CHF registered at a referral cardiovascular hospital in Iran were randomly allocated into three groups -trained by community health volunteers at patients’ homes, rained by formal health professionals at hospital; and a control group with no formal educational exposure. Data obtained through interviewing participants and using the Persian self-care of CHF index (pSCHFI) before and two months after interventions will be analysed using SAS and SPSS.Discussion: The results of this study may help health service systems, especially in countries with limited resources, make use of community volunteers to teach patients with CHF to develop self-care behaviors and skills, reducing the cost of care and improving CHF outcomes. Also, this home-based educational strategy using face-to-face training, if successful, may provide psychosocial supports for patients suffering from chronic illnesses.Trial registration number: ACTRN12614000788673(Australian New Zealand Clinical Trials Registry)

Signatures of material and optical chirality:Origins and measures

Chirality in materials and light is of abiding interest across a broad range of scientific disciplines. This article discusses present and emerging issues in relation to molecular and optical chirality, also including some important developments in chiral metamaterials. Quantifying the chirality of matter or light leads to issues concerning the most appropriate measures, such as a helicity parameter for specific chiral chromophores and technical measures of light chirality. An optical helicity and chirality density depend on a difference between the numbers of left- and right-handed photons in a beam. In connection with circularly polarized luminescence, adoption of the Stokes parameter to spontaneous emission from chiral molecules invites critical attention. Modern spectroscopic techniques are often based on the different response arising from left-handed circularly polarized light compared to right-handed light. This dissimilarity can be exploited as a foundation for the separation of chiral molecules, promising new avenues of application

Optically tailored access to metastable electronic states

On irradiating a molecular system with a laser beam of ultraviolet or visible frequency, photon absorption occurs when an electronic state is at a suitable energy level relative to an initial state. Despite meeting this criterion, interesting metastable states can remain inaccessible because of symmetry constraints. In this Letter a mechanism, based on the input of an off-resonant beam, is shown to enable the population of such states. This is achievable because the laser-modified process involves different selection rules compared to conventional photon absorption. The effects of applying the stimulus beam to either a one- or two-photon process are examined

Are Albumin Levels a Good Predictor of Mortality in Elderly Patients with Neck of Femur Fractures?

Background Neck of femur (NOF) fractures are associated with significant morbidity and mortality in elderly people with multiple co-morbidities; making management of this patient subgroup challenging. Predictors of an increase in morbidity and mortality would therefore provide a useful framework for the assessment and management of this demographic. Within the current literature, hypoalbuminaemia (<35g/dl) has been highlighted as being a good biochemical predictor of short-term mortality (<12 months). Our aims were to assess whether there was an association between low albumin levels and short-term mortality and whether the severity adversely affects outcomes. Materials and Methods Patients admitted to our large district hospital between January 2011 and December 2012 who had sustained a NOF fracture, were over 65 years old and had a pre-operative albumin level were included. The study concluded in July 2014. Demographic and pre-operative function and albumin data was collated retrospectively. Correlation with mortality was made. Results 471 patients had usable data. Mean pre-operative albumin level was 29.5g/dl (SD 6.22g/dl) in patients who died and 32.8g/dl (SD 6.43g/dl) in patients who survived during the study period. Pre-operative albumin level was significantly associated with survival (hazard ratio0.957: 95% CI (0.937, 0.978); p<0.001) A reduction of 1g/dl in pre-operative albumin is associated with an increased hazard of death of 4.3%. Conclusions Early identification of patients with hypoalbuminaemia on admission with a venous blood sample and timely input from orthogeriatrians could optimise these patients pre- and post-operatively. This may enable rates of morbidity and mortality to fall. Hypoalbuminaemia may be a reasonable predictor of shorter-term mortality in this patient subgroup. However, this may reflect existing co-morbidities rather than an isolated cause. This study supports a correlation between hypoalbuminaemia and poorer outcome for patients with NOF fractures

Electromagnetic trapping of chiral molecules: orientational effects of the irradiating beam

The photonic interaction generally responsible for the electromagnetic trapping of molecules is forward-Rayleigh scattering, a process that is mediated by transition electric dipoles connecting the ground electronic state and virtual excited states. Higher order electric and magnetic multipole contributions to the scattering amplitude are usually negligible. However, on consideration of chiral discrimination effects (in which an input light of left-handed circular polarization can present different observables compared to right-handed polarization, or molecules of opposite enantiomeric form respond differently to a set circular polarization), the mechanism must be extended to specifically accommodate transition magnetic dipoles. Moreover, it is important to account for the fact that chiral molecules are necessarily non-spherical, so that their interactions with a laser beam will have an orientational dependence. Using quantum electrodynamics, this article quantifies the extent of the energetic discrimination that arises when chiral molecules are optically trapped, placing particular emphasis on the orientational effects of the trapping beam. An in-depth description of the intricate ensemble-weighted method used to incorporate the latter is presented. It is thus shown that, when a mixture of molecular enantiomers is irradiated by a continuous beam of circularly polarized light, a difference arises in the relative rates of migration of each enantiomer in and out of the most intense regions of the beam. In consequence, optical trapping can be used as a means of achieving enantiomer separation

Bioactivation of Trimethoprim to Protein-Reactive Metabolites in Human Liver Microsomes

The formation of drug-protein adducts via metabolic activation and covalent binding may stimulate an immune response or may result in direct cell toxicity. Protein covalent binding is a potentially pivotal step in the development of idiosyncratic adverse drug reactions (IADRs). Trimethoprim (TMP)-sulfamethoxazole (SMX) is a combination antibiotic that commonly causes IADRs. Recent data suggest that the contribution of the TMP component of TMP-SMX to IADRs may be underappreciated. We previously demonstrated that TMP is bioactivated to chemically reactive intermediates that can be trapped in vitro by N-acetyl cysteine (NAC), and we have detected TMP-NAC adducts (i.e., mercapturic acids) in the urine of patients taking TMP-SMX. However, the occurrence and extent of TMP covalent binding to proteins was unknown. To determine the ability of TMP to form protein adducts, we incubated [14C]TMP with human liver microsomes in the presence and absence of NADPH. We observed protein covalent binding that was NADPH dependent and increased with incubation time and concentration of both protein and TMP. The estimated covalent binding was 0.8 nmol Eq TMP/mg protein, which is comparable to the level of covalent binding for several other drugs that have been associated with covalent binding–induced toxicity and/or IADRs. NAC and selective inhibitors of CYP2B6 and CYP3A4 significantly reduced TMP covalent binding. These results demonstrate for the first time that TMP bioactivation can lead directly to protein adduct formation, suggesting that TMP has been overlooked as a potential contributor of TMP-SMX IADRs

Dynamics of the dispersion interaction in an energy transfer system

On the propagation of resonant radiation through an optically dense system, photon capture is commonly followed by one or more near-field transfers of the resulting optical excitation. The process invokes secondary changes to the local electronic environment, shifting the electromagnetic interactions between participant chromophores and producing modified intermolecular forces. From the theory it emerges that energy transfer, when it occurs between chromophores with electronically dissimilar properties, can itself generate significant changes in the intermolecular potentials. This report highlights specific effects that can be anticipated when laser light propagates across an interface between differentially absorbing components in a model energy transfer system

Challenges in assessing the characteristics of influential public health research.

The development of frameworks to effectively measure both the scientific and social impact of research is a topic of international debate. This paper examines how Australian public health researchers in six fields (alcohol, drugs, injury, obesity, skin cancer and tobacco) classified the scientific and social impact of what they judged to be their five most influential papers. We compared classifications of researchers rated as most influential by their peers with those not as highly ranked. Highly ranked researchers more often indicated social impact characteristics (Χ2 = 8.13; P = 0.004) than their less influential colleagues. Traditional measures of scientific impact (publication in high impact journals and high citations) were nominated by all researchers regardless of peer-nominated research influence status. There was strong consensus on who were the most influential researchers in five of the six research fields examined. This would appear to provide a sound platform on which to base more qualitative, interview or portfolio-based investigations into the complexities of wider conceptions of research and researcher influence