Bacterial Attachment to Polymeric Materials Correlates with Molecular Flexibility and Hydrophilicity

A new class of material resistant to bacterial attachment has been discovered that is formed from polyacrylates with hydrocarbon pendant groups. In this study, the relationship between the nature of the hydrocarbon moiety and resistance to bacteria is explored, comparing cyclic, aromatic, and linear chemical groups. A correlation is shown between bacterial attachment and a parameter derived from the partition coefficient and the number of rotatable bonds of the materials\u27 pendant groups. This correlation is applicable to 86% of the hydrocarbon pendant moieties surveyed, quantitatively supporting the previous qualitative observation that bacteria are repelled from poly(meth)acrylates containing a hydrophilic ester group when the pendant group is both rigid and hydrophobic. This insight will help inform and predict the further development of polymers resistant to bacterial attachment

Subaru FOCAS Spectroscopic Observations of High-Redshift Supernovae

We present spectra of high-redshift supernovae (SNe) that were taken with the Subaru low resolution optical spectrograph, FOCAS. These SNe were found in SN surveys with Suprime-Cam on Subaru, the CFH12k camera on the Canada-France-Hawaii Telescope (CFHT), and the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). These SN surveys specifically targeted z>1 Type Ia supernovae (SNe Ia). From the spectra of 39 candidates, we obtain redshifts for 32 candidates and spectroscopically identify 7 active candidates as probable SNe Ia, including one at z=1.35, which is the most distant SN Ia to be spectroscopically confirmed with a ground-based telescope. An additional 4 candidates are identified as likely SNe Ia from the spectrophotometric properties of their host galaxies. Seven candidates are not SNe Ia, either being SNe of another type or active galactic nuclei. When SNe Ia are observed within a week of maximum light, we find that we can spectroscopically identify most of them up to z=1.1. Beyond this redshift, very few candidates were spectroscopically identified as SNe Ia. The current generation of super red-sensitive, fringe-free CCDs will push this redshift limit higher.Comment: 19 pages, 26 figures. PASJ in press. see http://www.supernova.lbl.gov/2009ClusterSurvey/ for additional information pertaining to the HST Cluster SN Surve

Making connections and promoting the profession : social media use by World Federation of Occupational Therapists member organisations

Background World Federation of Occupational Therapists (WFOT) member organisations comprise 77 national occupational therapy organisations across the world. Each national organisation interacts with its members and the public using diverse methods. Increasingly, national organisations are broadening their communication methods. Objective The objective of this study was to examine if and how occupational therapy organisations are using social media for communication, and if so, the types of concerns or barriers they experience and what role they anticipate social media might play in the near future. Methods An online survey was developed; 57 of 77 WFOT member organisations responded. Findings This study identified that WFOT national organisations are using social media, to varying degrees, with or without an individual formally assigned to manage social media. Respondents reported that they used social media to: communicate with members, promote the organisation and promote the profession. Commonly expressed needs included assistance with guidelines for ethical social media use, developing technical expertise, and recognition of limits of time and competing priorities. Recommendations arising from this research are at the global, national, local and individual levels and incorporate active dissemination and pure diffusion approaches. Taking steps to increase the use of social media could indirectly impact occupational therapy practice through enhancing organisations’ abilities to support practitioners to enhance their practice. Limitations and recommendations for further research Although 57% of WFOT member organisations returned usable responses, there may be some additional perspectives that were not captured. It would be helpful to contact non-responding organisations to explore their social media use and plans. Further research could examine how future initiatives put in place by WFOT impact social media use by member organisation

Combinatorial discovery of polymers resistant to bacterial attachment

Bacterial attachment and subsequent biofilm formation are key challenges to the long term performance of many medical devices. Here, a high throughput approach coupled with the analysis of surface structure-property relationships using a chemometics approach has been developed to simultaneously investigate the interaction of bacteria with hundreds of polymeric materials on a microarray format. Using this system, a new group of materials comprising ester and hydrophobic moieties are identified that dramatically reduce the attachment of clinically relevant, pathogenic bacteria (Pseudomonas aeruginosa, Staphylococcus aureus and uropathogenic Escherichia coli). Hit materials coated on silicone catheters resulted in up to a 30 fold reduction in coverage compared to a commercial silver embedded catheter, which has been proven to half the incidence of clinically acquired infection. These polymers represent a new class of materials resistant to bacterial attachment that could not have been predicted from the current understanding of bacteria-surface interactions

Looking Beyond Lambda with the Union Supernova Compilation

The recent robust and homogeneous analysis of the world's supernova distance-redshift data, together with cosmic microwave background and baryon acoustic oscillation data, provides a powerful tool for constraining cosmological models. Here we examine particular classes of scalar field, modified gravity, and phenomenological models to assess whether they are consistent with observations even when their behavior deviates from the cosmological constant Lambda. Some models have tension with the data, while others survive only by approaching the cosmological constant, and a couple are statistically favored over LCDM. Dark energy described by two equation of state parameters has considerable phase space to avoid Lambda and next generation data will be required to constrain such physics.Comment: 32 pages, 19 figure

Constraining dust and color variations of high-z SNe using NICMOS on Hubble Space Telescope

We present data from the Supernova Cosmology Project for five high redshift Type Ia supernovae (SNe Ia) that were obtained using the NICMOS infrared camera on the Hubble Space Telescope. We add two SNe from this sample to a rest-frame I-band Hubble diagram, doubling the number of high redshift supernovae on this diagram. This I-band Hubble diagram is consistent with a flat universe (Omega_Matter, Omega_Lambda= 0.29, 0.71). A homogeneous distribution of large grain dust in the intergalactic medium (replenishing dust) is incompatible with the data and is excluded at the 5 sigma confidence level, if the SN host galaxy reddening is corrected assuming R_V=1.75. We use both optical and infrared observations to compare photometric properties of distant SNe Ia with those of nearby objects. We find generally good agreement with the expected color evolution for all SNe except the highest redshift SN in our sample (SN 1997ek at z=0.863) which shows a peculiar color behavior. We also present spectra obtained from ground based telescopes for type identification and determination of redshift.Comment: 30 pages, 10 figures; accepted for publication in ApJ; v2: revised to match the version in the journa

Aqueous Two‐Phase System Patterning of Microbubbles: Localized Induction of Apoptosis in Sonoporated Cells

Ultrasound‐driven microbubbles produce mechanical forces that can disrupt cell membranes (sonoporation). However, it is difficult to control microbubble location with respect to cells. This lack of control leads to low sonoporation efficiencies and variable outcomes. In this study, aqueous two‐phase system (ATPS) droplets are used to localize microbubbles in select micro‐regions at the surface of living cells. This is achieved by stably partitioning microbubbles in dextran (DEX) droplets, deposited on living adherent cells in medium containing polyethylene glycol (PEG). The interfacial energy at the PEG‐DEX interface overcomes microbubble buoyancy and prevents microbubbles from floating away from the cells. Spreading of the small DEX droplets retains microbubbles at the cell surface in defined lateral positions without the need for antibody or cell‐binding ligand conjugation. The patterned microbubbles are activated on a cell monolayer exposed to a broadly applied ultrasound field (center frequency 1.25 MHz, active element diameter 0.6 cm, pulse duration 8 μs or 30 s). This system enables efficient testing of different ultrasound conditions for their effects on sonoporation‐mediated membrane disruption and cell viability. Regions of cells without patterned microbubbles show no injury or membrane disruption. In microbubble patterned regions, 8 μs ultrasound pulses (0.2‐0.6 MPa) produce cell death that is primarily apoptotic. Ultrasound‐induced apoptosis increases with higher extracellular calcium concentrations, with cells displaying all of the hallmarks of apoptosis including annexinV labeling, loss of mitochondrial membrane potential, caspase activation and changes in nuclear morphology. A new method is described for patterning microbubbles on cell monolayers to target ultrasound treatment to cells. This novel platform provides a controlled system for high throughput testing of the effects of ultrasound‐mediated cell membrane disruption on cell physiology. Using this patterning method, it is possible to induce apoptosis in select populations of cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99004/1/3420_ftp.pd