975 research outputs found
Spiropyran Photoisomerization Dynamics in Multiresponsive Hydrogels
Light-responsive, spiropyran-functionalized hydrogels have been used to create reversibly photoactuated structures for applications ranging from microfluidics to nonlinear optics. Tailoring a spiropyran-functionalized hydrogel system for a particular application requires an understanding of how co-monomer composition affects the switching dynamics of the spiropyran chromophore. Such gels are frequently designed to be responsive to different stimuli such as light, temperature, and pH. The coupling of these influences can significantly alter spiropyran behavior in ways not currently well understood. To better understand the influence of responsive co-monomers on the spiropyran isomerization dynamics, we use UV-vis spectroscopy and time-dependent fluorescence intensity measurements to study spiropyran-modified hydrogels polymerized from four common hydrogel precursors of different pH and temperature responsivity: acrylamide, acrylic acid, N-isopropylacrylamide, and 2-(dimethylamino)ethyl methacrylate. In acidic and neutral gels, we observe unusual nonmonotonic, triexponential fluorescence dynamics under 405 nm irradiation that cannot be explicated by either the established spiropyran-merocyanine interconversion model or hydrolysis. To explain these results, we introduce an analytical model of spiropyran interconversions that includes H-aggregated merocyanine and its light-triggered disaggregation under 405 nm irradiation. This model provides an excellent fit to the observed fluorescence dynamics and elucidates exactly how creating an acidic internal gel environment promotes the fast and complete conversion of the hydrophilic merocyanine speciesto the hydrophobic spiropyran form, which is desired in most light-sensitive hydrogel actuators. This can be achieved by incorporating acrylic acid monomers and by minimizing the aggregate concentration. Beyond spiropyran-functionalized gel actuators, these conclusions are particularly critical for nonlinear optical computing applications
PIN24 The Impact Of Renal Impairment, Inflammatory Bowel Disease And Advanced Age On Mortality Among Hospitalized Patients With Clostridium Difficile-Associated Diarrhea
Interdisciplinary communication in the intensive care unit
Background. Patient safety research has shown poor communication among intensive care unit (ICU) nurses and doctors to be a common causal factor underlying critical incidents in intensive care. This study examines whether ICU doctors and nurses have a shared perception of interdisciplinary communication in the UK ICU. Methods. Cross-sectional survey of ICU nurses and doctors in four UK hospitals using a previously established measure of ICU interdisciplinary collaboration. Results. A sample of 48 doctors and 136 nurses (47% response rate) from four ICUs responded to the survey. Nurses and doctors were found to have differing perceptions of interdisciplinary communication, with nurses reporting lower levels of communication openness between nurses and doctors. Compared with senior doctors, trainee doctors also reported lower levels of communication openness between doctors. A regression path analysis revealed that communication openness among ICU team members predicted the degree to which individuals reported understanding their patient care goals (adjR2 = 0.17). It also showed that perceptions of the quality of unit leadership predicted open communication. Conclusions. Members of ICU teams have divergent perceptions of their communication with one another. Communication openness among team members is also associated with the degree to which they understand patient care goals. It is necessary to create an atmosphere where team members feel they can communicate openly without fear of reprisal or embarrassment
Survivorship care planning in gynecologic oncology perspectives from patients, caregivers, and health care providers
Purpose This qualitative study sought to describe the challenges following treatment and the preferences regarding survivorship care among patients treated for gynecological cancer, their caregivers, and health care providers. Methods Between July and August 2017, in-depth semi-structured interviews regarding survivorship were conducted at a large academic hospital in the USA among patients who recently completed treatment (<â12 months) for a gynecological cancer (ovarian, endometrial, cervical, and vulvar) and their primary caregivers. A focus group was conducted among health care providers (oncologists, nurses, and fellows). Main themes were identified using descriptive content analysis. Results A total of 30 individuals participated in this study (13 patients, 9 caregivers, 8 health care providers). Almost all participants reported a desire for more information on how to address survivorship needs, specifically as they related to side effects, follow-up schedule, and psychological assistance. Despite this uniformly identified need for more information, preferences for survivorship care planning differed across cancer types and individuals, with respect to content, timing, and mode of delivery. Health care providers expressed challenges in communicating with patients about survivorship, a desire to shift post-treatment conversations to the goal of improving quality of life as opposed to focusing on disease recurrence, and an unmet need for disease specific and individualized survivorship care planning. Conclusions Patients, caregivers, and health care providers each expressed a need for gynecologic cancer-tailored survivorship care resources
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Longitudinal Course of Deficient Emotional Self-Regulation CBCL Profile in Youth with ADHD: Prospective Controlled Study
Background: While symptoms of deficient emotional self-regulation (DESR) have been long associated with attention-deficit/hyperactivity disorder (ADHD), there has been limited investigation of this aspect of the clinical picture of the disorder. The main aim of this study was to examine the predictive utility of DESR in moderating the course of ADHD children into adolescence. Methods: Subjects comprised 177 children with and 204 children without ADHD followed for an average of 4 years (aged 6â18 years at baseline, 54% male). Subjects were assessed with structured diagnostic interviews and measures of psychosocial functioning. DESR was defined by the presence (n = 79) or absence (n = 98) of Child Behavior Checklist (CBCL)-DESR profile (score â„ 180 < 210 total of Attention, Aggression, and Anxious/Depressed subscales) at the baseline assessment. Results: Of subjects with DESR at baseline, 57% had DESR at follow-up. Persistent ADHD was significantly associated with DESR at follow-up (x = 15.37, P < 0.001). At follow-up, ADHD + DESR subjects had significantly more comorbidities (z = 2.55, P = 0.01), a higher prevalence of oppositional defiant disorder (z = 3.01, P = 0.003), and more impaired CBCL social problems t-score (t = 2.41, P = 0.02) versus ADHD subjects. Conclusion: This work suggests that a positive CBCL-DESR profile predicts subsequent psychopathology and functional impairments in children with ADHD suggesting that it has the potential to help identify children with ADHD at high risk for compromised outcomes
Energy Transfer and Trapping in Red-Chlorophyll-Free Photosystem I from Synechococcus WH 7803
We report for the first time steady-state and time-resolved emission properties of photosystem I (PSI) complexes isolated from the cyanobacterial strain Synechococcus WH 7803. The PSI complexes from this strain display an extremely small fluorescence emission yield at 77 K, which we attribute to the absence of so-called red antenna chlorophylls, chlorophylls with absorption maxima at wavelengths longer than those of the primary electron donor P700. Emission measurements at room temperature with picosecond time resolution resulted in two main decay components with lifetimes of about 7.5 and 18 ps and spectra peaking at about 685 nm. Especially in the red flanks, these spectra show consistent differences, which means that earlier proposed models for the primary charge separation reactions based on ultrafast (âŒ1 ps) excitation equilibration processes cannot describe the data. We show target analyses of a number of alternative models and conclude that a simple model (Ant2)* (Ant1/RC)* â RP2 can explain the time-resolved emission data very well. In this model, (Ant2)* represents chlorophylls that spectrally equilibrate in about 7.5 ps and in which RP2 represents the "final" radical pair P70
Coupling Modes and Stoichiometry of Clâ/HCO3â Exchange by slc26a3 and slc26a6
The SLC26 transporters are a family of mostly luminal Clâ and HCO3â transporters. The transport mechanism and the Clâ/HCO3â stoichiometry are not known for any member of the family. To address these questions, we simultaneously measured the HCO3â and Clâ fluxes and the current or membrane potential of slc26a3 and slc26a6 expressed in Xenopus laevis oocytes and the current of the transporters expressed in human embryonic kidney 293 cells. slc26a3 mediates a coupled 2Clâ/1HCO3â exchanger. The membrane potential modulated the apparent affinity for extracellular Clâ of Clâ/HCO3â exchange by slc26a3. Interestingly, the replacement of Clâ with NO3â or SCNâ uncoupled the transport, with large NO3â and SCNâ currents and low HCO3â transport. An apparent uncoupled current was also developed during the incubation of slc26a3-expressing oocytes in HCO3â-buffered Clâ-free media. These findings were used to develop a turnover cycle for Clâ and HCO3â transport by slc26a3. Clâ and HCO3â flux measurements revealed that slc26a6 mediates a 1Clâ/2HCO3â exchange. Accordingly, holding the membrane potential at 40 and â100 mV accelerated and inhibited, respectively, Clâ-mediated HCO3â influx, and holding the membrane potential at â100 mV increased HCO3â-mediated Clâ influx. These findings indicate that slc26a6 functions as a coupled 1Clâ/2HCO3â exchanger. The significance of isoform-specific Clâ and HCO3â transport stoichiometry by slc26a3 and slc26a6 is discussed in the context of diseases of epithelial Clâ absorption and HCO3â secretion
Skills-based intervention to enhance collaborative decision-making: systematic adaptation and open trial protocol for veterans with psychosis
Background: Collaborative decision-making is an innovative decision-making approach that assigns equal power and responsibility to patients and providers. Most veterans with serious mental illnesses like schizophrenia want a greater role in treatment decisions, but there are no interventions targeted for this population. A skills-based intervention is promising because it is well-aligned with the recovery model, uses similar mechanisms as other evidence-based interventions in this population, and generalizes across decisional contexts while empowering veterans to decide when to initiate collaborative decision-making. Collaborative Decision Skills Training (CDST) was developed in a civilian serious mental illness sample and may fill this gap but needs to undergo a systematic adaptation process to ensure fit for veterans. Methods: In aim 1, the IM Adapt systematic process will be used to adapt CDST for veterans with serious mental illness. Veterans and Veteranâs Affairs (VA) staff will join an Adaptation Resource Team and complete qualitative interviews to identify how elements of CDST or service delivery may need to be adapted to optimize its effectiveness or viability for veterans and the VA context. During aim 2, an open trial will be conducted with veterans in a VA Psychosocial Rehabilitation and Recovery Center (PRRC) to assess additional adaptations, feasibility, and initial evidence of effectiveness. Discussion: This study will be the first to evaluate a collaborative decision-making intervention among veterans with serious mental illness. It will also contribute to the fieldâs understanding of perceptions of collaborative decision-making among veterans with serious mental illness and VA clinicians, and result in a service delivery manual that may be used to understand adaptation needs generally in VA PRRCs. Trial registration: ClinicalTrials.gov Identifier: NCT0432494
Topological wave functions and heat equations
It is generally known that the holomorphic anomaly equations in topological
string theory reflect the quantum mechanical nature of the topological string
partition function. We present two new results which make this assertion more
precise: (i) we give a new, purely holomorphic version of the holomorphic
anomaly equations, clarifying their relation to the heat equation satisfied by
the Jacobi theta series; (ii) in cases where the moduli space is a Hermitian
symmetric tube domain , we show that the general solution of the anomaly
equations is a matrix element \IP{\Psi | g | \Omega} of the
Schr\"odinger-Weil representation of a Heisenberg extension of , between an
arbitrary state and a particular vacuum state .
Based on these results, we speculate on the existence of a one-parameter
generalization of the usual topological amplitude, which in symmetric cases
transforms in the smallest unitary representation of the duality group in
three dimensions, and on its relations to hypermultiplet couplings, nonabelian
Donaldson-Thomas theory and black hole degeneracies.Comment: 50 pages; v2: small typos fixed, references added; v3: cosmetic
changes, published version; v4: typos fixed, small clarification adde
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