Ethanol induces the formation of water-permeable defects in model bilayers of skin lipids

We show that ethanol can induce the formation of water-permeable defects in model membranes of skin, providing a fresh perspective on ethanol as a membrane modulator. We rationalise our findings in terms of the chemical nature of ethanol, i.e., a combination of its hydrogen bonding propensity and amphiphilic character

An Analysis of Efficiency Improvements in Residential Sized Heat Pumps

The objectives of this study included: (1) development of classes of heat pumps, (2) evaluation and selection of a suitable heat pump design model, (3) characterization of suitable baseline heat pump designs, (4) selection of design options that can be used to improve heat pump efficiency, and (5) development of heat pump designs to cover the whole spectrum of efficiencies available today and those that may be technologically feasible in the next few years

Water permeation through stratum corneum lipid bilayers from atomistic simulations

Stratum corneum, the outermost layer of skin, consists of keratin filled rigid non-viable corneocyte cells surrounded by multilayers of lipids. The lipid layer is responsible for the barrier properties of the skin. We calculate the excess chemical potential and diffusivity of water as a function of depth in lipid bilayers with compositions representative of the stratum corneum using atomistic molecular dynamics simulations. The maximum in the excess free energy of water inside the lipid bilayers is found to be twice that of water in phospholipid bilayers at the same temperature. Permeability, which decreases exponentially with the free energy barrier, is reduced by several orders of magnitude as compared to with phospholipid bilayers. The average time it takes for a water molecule to cross the bilayer is calculated by solving the Smoluchowski equation in presence of the free energy barrier. For a bilayer composed of a 2:2:1 molar ratio of ceramide NS 24:0, cholesterol and free fatty acid 24:0 at 300K, we estimate the permeability P=3.7e-9 cm/s and the average crossing time \tau_{av}=0.69 ms. The permeability is about 30 times smaller than existing experimental results on mammalian skin sections.Comment: latex, 8 pages, 6 figure

Building Energy Use and Conservation in Cycle VIII of the Texas Institutional Conservation Program

Sixty-two technical assistance (energy audit) reports by twelve different consulting firms representing fifteen independent school districts, nine hospitals, and five colleges have been reviewed to assess energy use characteristics and recommended energy saving measures. Such measures include both maintenance and operation (H&O) measures (generally regarded as "low-cost, no-cost") and energy conservation (ECH) measures (generally more expensive and requiring outside skills). Implementation cost, annual savings of energy and costs, and paybacks were reported for all M&Os and ECHs. Measures were broken down by the consulting firms according to energy use characteristics and categories, and it was determined that average costs for electricity and gas, before implementation of M&Os and ECHs, were $0.0596/KWH and$4.85/MMBTU respectively. The total implementation cost and projected annual savings for the M&Os are $73,000 and$223,000 respectively, yielding a four-month payback. The corresponding results for implementation of ECHs are $2,232,000 and$555,000, resulting in a four-year payback. Also, some obvious problems in the preparation of technical assistance reports along with the general background and implementation of the Institutional Conservation Program in Texas, resulting from the National Energy Act of 1978, are discussed

Impact of oxetane incorporation on the structure and stability of alpha-helical peptides

Peptide-based drugs combine advantages of larger biological therapeutics with those of small molecule drugs, but they generally display poor permeability and metabolic stability. Recently, we introduced a new type of peptide bond isostere, in which the backbone carbonyl is replaced with a 3-amino oxetane heterocycle, into short linear peptides with the aim of improving their therapeutic potential. In this study, we have explored the impact of oxetane modification on α-helical peptides to establish whether or not this modification is tolerated in this biologically important structural motif. The oxetane modification was introduced at two positions in a well-characterised helical peptide sequence, and circular dichroism and NMR spectroscopy were used to measure the resulting secondary structure content under different experimental conditions. Our data demonstrated that introduction of an oxetane into the peptide backbone results in a significant loss of helicity, regardless of where in the sequence the modification is placed. The molecular determinants of this destabilisation were then explored using steered molecular dynamics simulations, a computational method analogous to single molecule spectroscopy. Our simulations indicated that oxetane modification introduces a kink in the helical axis, alters the dihedral angles of residues up to three positions away from the modification, and disrupts the (i, i + 4) hydrogen bonding pattern characteristic of α-helices in favour of new, short-range hydrogen bonds. The detailed structural understanding provided in this work can direct future design of chemically modified peptides

The Care Home Independent Prescribing Pharmacist Study (CHIPPS)—a non- randomised feasibility study of independent pharmacist prescribing in care homes

Background Residents in care homes are often very frail, have complex medicine regimens and are at high risk of adverse drug events. It has been recommended that one healthcare professional should assume responsibility for their medicines management. We propose that this could be a pharmacist independent prescriber (PIP). This feasibility study aimed to test and refine the service specification and proposed study processes to inform the design and outcome measures of a definitive randomised controlled trial to examine the clinical and cost effectiveness of PIPs working in care homes compared to usual care. Specific objectives included testing processes for participant identification, recruitment and consent and assessing retention rates; determining suitability of outcome measures and data collection processes from care homes and GP practices to inform selection of a primary outcome measure; assessing service and research acceptability; and testing and refining the service specification. Methods Mixed methods (routine data, questionnaires and focus groups/interviews) were used in this non-randomised open feasibility study of a 3-month PIP intervention in care homes for older people. Data were collected at baseline and 3 months. One PIP, trained in service delivery, one GP practice and up to three care homes were recruited at each of four UK locations. For ten eligible residents (≥ 65 years, on at least one regular medication) in each home, the PIP undertook management of medicines, repeat prescription authorisation, referral to other healthcare professionals and staff training. Outcomes (falls, medications, resident’s quality of life and activities of daily living, mental state and adverse events) were described at baseline and follow-up and assessed for inclusion in the main study. Participants’ views post-intervention were captured in audio-recorded focus groups and semi-structured interviews. Transcripts were thematically analysed. Results Across the four locations, 44 GP practices and 16 PIPs expressed interest in taking part; all care homes invited agreed to take part. Two thirds of residents approached consented to participate (53/86). Forty residents were recruited (mean age 84 years; 61% (24) were female), and 38 participants remained at 3 months (two died). All GP practices, PIPs and care homes were retained. The number of falls per participating resident was selected as the primary outcome, following assessment of the different outcome measures against predetermined criteria. The chosen secondary outcomes/outcome measures include total falls, drug burden index (DBI), hospitalisations, mortality, activities of daily living (Barthel (proxy)) and quality of life (ED-5Q-5 L (face-to-face and proxy)) and selected items from the STOPP/START guidance that could be assessed without need for clinical judgement. No adverse drug events were reported. The PIP service was generally well received by the majority of stakeholders (care home staff, GPS, residents, relatives and other health care professionals). PIPs reported feeling more confident implementing change following the training but reported challenges accommodating the new service within their existing workload. Conclusion Implementing a PIP service in care homes is feasible and acceptable to care home residents, staff and clinicians. Findings have informed refinements to the service specification, PIP training, recruitment to the future RCT and the choice of outcomes and outcome measures. The full RCT with internal pilot started in February 2016 and results are expected to be available in mid late 2020

Utilising Drone Technology in Primatology for 3D Mapping

Emergent Unmanned Aerial System (or drone) technology allows the 3-dimensional mapping of forest landscapes, allowing a new perspective of arboreal primate habitat use. Utilising UASs in primatological studies enables the assessment of habitat quality for different arboreal primate species, the identification of discreet forms of anthropogenic disturbance (such as historical selective logging), and detailed investigation of canopy use by arboreal primate species. Combining 3D canopy structure with microclimate measurements, we can see how canopy structure buffers solar radiation and how arboreal species may be affected by future climate change. We present data on a study of the arboreal primate community in a lowland section of the Gunung Leuser Ecosystem in northern Sumatra, focusing on how 3D canopy structure effects ranging (siamang, Symphalangus syndactylus), different primate species’ population densities (lar gibbon, Hylobates lar, siamang and Thomas langur, Presbytis thomasi) and habitat selection (orang-utan, Pongo abelii and siamang) and how UAS technology can be utilised in other future studies; the potential opportunities, challenges and pitfalls

Interaction of β-Sheet Folds with a Gold Surface

The adsorption of proteins on inorganic surfaces is of fundamental biological importance. Further, biomedical and nanotechnological applications increasingly use interfaces between inorganic material and polypeptides. Yet, the underlying adsorption mechanism of polypeptides on surfaces is not well understood and experimentally difficult to analyze. Therefore, we investigate here the interactions of polypeptides with a gold(111) surface using computational molecular dynamics (MD) simulations with a polarizable gold model in explicit water. Our focus in this paper is the investigation of the interaction of polypeptides with β-sheet folds. First, we concentrate on a β-sheet forming model peptide. Second, we investigate the interactions of two domains with high β-sheet content of the biologically important extracellular matrix protein fibronectin (FN). We find that adsorption occurs in a stepwise mechanism both for the model peptide and the protein. The positively charged amino acid Arg facilitates the initial contact formation between protein and gold surface. Our results suggest that an effective gold-binding surface patch is overall uncharged, but contains Arg for contact initiation. The polypeptides do not unfold on the gold surface within the simulation time. However, for the two FN domains, the relative domain-domain orientation changes. The observation of a very fast and strong adsorption indicates that in a biological matrix, no bare gold surfaces will be present. Hence, the bioactivity of gold surfaces (like bare gold nanoparticles) will critically depend on the history of particle administration and the proteins present during initial contact between gold and biological material. Further, gold particles may act as seeds for protein aggregation. Structural re-organization and protein aggregation are potentially of immunological importance

Production and perception of situationally variable alarm calls in wild tufted capuchin monkeys (Cebus apella nigritus)

Many mammalian and avian species produce conspicuous vocalizations upon encountering a predator, but vary their calling based on risk urgency and/or predator type. Calls falling into the latter category are termed “functionally referential” if they also elicit predator-appropriate reactions in listeners. Functionally referential alarm calling has been well documented in a number of Old World monkeys and lemurs, but evidence among Neotropical primates is limited. This study investigates the alarm call system of tufted capuchin monkeys (Cebus apella nigritus) by examining responses to predator and snake decoys encountered at various distances (reflecting differences in risk urgency). Observations in natural situations were conducted to determine if predator-associated calls were given in additional contexts. Results indicate the use of three call types. “Barks” are elicited exclusively by aerial threats, but the call most commonly given to terrestrial threats (the “hiccup”) is given in nonpredatory contexts. The rate in which this latter call is produced reflects risk urgency. Playbacks of these two call types indicate that each elicits appropriate antipredator behaviors. The third call type, the “peep,” seems to be specific to terrestrial threats, but it is unknown if the call elicits predator-specific responses. “Barks” are thus functionally referential aerial predator calls, while “hiccups” are better seen as generalized disturbance calls which reflect risk urgency. Further evidence is needed to draw conclusions regarding the “peep.” These results add to the evidence that functionally referential aerial predator alarm calls are ubiquitous in primates, but that noncatarrhine primates use generalized disturbance calls in response to terrestrial threats