Nanoparticle assemblies with long-range packing order and preferred crystallographic orientation of building blocks, i.e., mesocrystals, are of high interest not only because of their unique physical ...properties but also due to their complex structure and morphogenesis. In this study, faceted mesocrystals have been assembled from the dispersion of truncated cubic-shaped iron oxide nanoparticles stabilized by oleic acid (OA) molecules using the nonsolvent “gas phase diffusion technique” into an organic solvent. The effects of synthesis conditions as well as of the nanoparticle size and shape on the structure and morphogenesis of mesocrystals were examined. The interactions of OA-capped iron oxide nanoparticles with solvent molecules were probed by analytical ultracentrifugation and double difference pair distribution function analysis. It was shown that the structure of the organic shell significantly depends on the nature and polarity of solvent molecules. For the nonpolar solvents, the interaction of the aliphatic chains of OA molecules with the solvent molecules is favorable and the chains extend into the solvent. The solvation shell around the nanoparticles is more extended in nonpolar and more compact in polar solvents. There is a clear trend for more spherical particles to be assembled into the fcc superlattice, whereas less truncated cubes form rhombohedral and tetragonal structures. The observed changes in packing symmetry are reminiscent of structural polymorphism known for “classical” (atomic and molecular) crystals.
One aspect of the research on mesocrystals nowadays focuses on applications, whereby such applications demand mesocrystals with a tunable size. To achieve this task, more effort needs to be ...undertaken to understand how mesocrystals form, which parameters influence mesocrystal formation, and which kind of structure results from the nanoparticle assembly. Within this communication, we demonstrate for faceted mesocrystals assembled from iron oxide nanocubes stabilized by oleic acid that the proper choice of crystallization conditions in the gas phase diffusion setup is essential to achieve this task. The appropriate choice of substrate, dispersion and destabilizing agents, additive, nanocrystal concentration, crystallization kinetics, and duration allows growing faceted iron oxide mesocrystals with sizes ranging from a few micrometers up to almost a millimeter. By these findings supported by light and scanning electron microscopy, we show that in this system, heterogeneous nucleation is the predominant mechanism for mesocrystal formation on a solid substrate. Additionally, other surfactants than oleic acid can also act as molecular additives to support mesocrystal growth. These findings should be transferable to tune the size and quality of other self-assembled mesocrystals.
To compare cost and outcomes of surgical and percutaneous treatments of pathologic vertebral fractures.
Standard Medicare 5% anonymized inpatient files (1999-2009) were retrospectively reviewed. ...Patients with a diagnosis of vertebral fracture without spinal cord injury and primary or metastatic bony malignancy were divided into percutaneous or surgical groups based on whether they received vertebroplasty/kyphoplasty or surgical treatment. Patients who had no intervention or both interventions were excluded. Cost, length of stay, and type of discharge were examined while controlling for demographic and comorbidity variables.
A total of 451 patients were included; 52% received percutaneous treatment and 48% received surgery. Patients treated percutaneously were older (P < .001) and more likely to be female (P = .04). Percutaneous therapy predicted $14,862 less Medicare cost and $13,565 less overall cost (P < .001 for both), and 4.1 fewer inpatient days (P < .001). Patients who underwent surgery had higher odds of death (odds ratio = 3.38, P = .016), discharge to a rehabilitation facility (odds ratio = 3.3, P = .003), and transfer to another inpatient facility (odds ratio = 8.53, P < .001), and lower odds of discharge to home (odds ratio = 0.42, P < .001) and hospice (odds ratio = 0.08, P = .002).
In a Medicare population with bony malignancy and vertebral fractures, percutaneous therapy predicted significantly reduced cost and length of stay versus surgery. Patients who underwent percutaneous therapy were significantly less likely to die, be transferred, or be discharged to rehabilitation facilities, and were more likely to be discharged to home or hospice.
Background
Using structured templates to guide providers in communicating key information in electronic referrals is an evidence-based practice for improving care quality. To facilitate referrals in ...Veterans Health Administration’s (VA) Cerner Millennium electronic health record, VA and Cerner have created “Care Pathways”—templated electronic forms, capturing needed information and prompting ordering of appropriate pre-referral tests.
Objective
To inform their iterative improvement, we sought to elicit experiences, perceptions, and recommendations regarding Care Pathways from frontline clinicians and staff in the first VA site to deploy Cerner Millennium.
Design
Qualitative interviews, conducted 12–20 months after Cerner Millennium deployment.
Participants
We conducted interviews with primary care providers, primary care registered nurses, and specialty providers requesting and/or receiving referrals.
Approach
We used rapid qualitative analysis. Two researchers independently summarized interview transcripts with bullet points; summaries were merged by consensus. Constant comparison was used to sort bullet points into themes. A matrix was used to view bullet points by theme and participant.
Results
Some interviewees liked aspects of the Care Pathways, expressing appreciation of their premise and logic. However, interviewees commonly expressed frustration with their poor usability across multiple attributes. Care Pathways were reported as being inefficient; lacking simplicity, naturalness, consistency, and effective use of language; imposing an unacceptable cognitive load; and not employing forgiveness and feedback for errors. Specialists reported not receiving the information needed for referral triaging.
Conclusions
Cerner Millennium’s Care Pathways, and their associated organizational policies and processes, need substantial revision across several usability attributes. Problems with design and technical limitations are compounding challenges in using standardized templates nationally, across VA sites having diverse organizational and contextual characteristics. VA is actively working to make improvements; however, significant additional investments are needed for Care Pathways to achieve their intended purpose of optimizing specialty care referrals for Veterans.
This letter describes the formation and detailed characterization of iron oxide mesocrystals produced by the directed assembly of superparamagnetic iron oxide-truncated nanocubes using the slow ...evaporation of the solvent within an externally applied homogeneous magnetic field. Anisotropic mesocrystals with an elongation along the direction of the magnetic field can be produced. The structure of the directed mesocrystals is compared to self-assembled mesocrystalline films, which are formed without the influence of a magnetic field. The remarkable structural difference of mesocrystals produced within the external magnetic field from those self-assembled without field indicates that the specific nanoparticle ordering within the superstructure is driven by competing of two types of anisotropic interactions caused by particle shape (i.e., faceting) and orientation of the magnetic moment (i.e., easy axes:
). Hence, these findings provide a fundamental understanding of formation mechanisms and structuring of mesocrystals built up from superparamagnetic nanoparticles and how a magnetic field can be used to design anisotropic mesocrystals with different structures.
Abstract Background The Veterans Health Administration (VA) Patient Aligned Care Team (PACT) initiative aims to ensure that all patients receive care consistent with medical home principles. Women ...veterans’ unique care needs and minority status within the VA pose challenges to delivery of equitable, comprehensive primary care for this population. Currently, little is known about whether and/or how PACT should be tailored to better meet women veteran needs. Methods In 2014, we conducted semistructured interviews with 73 primary care providers and staff to examine facilitators and barriers encountered in providing PACT-principled care to women veterans. Respondents were located in eight VA medical centers in eight different states across the United States. Results Respondents perceived PACT as improving continuity of care for patients and as increasing ability of nursing staff to practice at the top of their license. However, the implementation of core medical home features and team huddles was inconsistent and varied both within and across medical centers. Short staffing, inclusion of part-time providers on teams, balancing performance requirements for continuity and same-day access, and space constraints were identified as ongoing barriers to PACT implementation. Challenges unique to care of women veterans included an higher prevalence of psychosocial needs, the need for specialized training of primary care personnel, and short staffing owing to additional sharing of primary care support staff with specialist providers. Conclusion Providers and staff face unique challenges in delivering comprehensive primary care to women veterans that may require special policy, practice, and management action if benefits of PACT are to be fully realized for this population.
Much of dissemination, implementation, and improvement (DII) science is conducted by social scientists, healthcare practitioners, and biomedical researchers. While each of these groups has its own ...venues for sharing methods and findings, forums that bring together the diverse DII science workforce provide important opportunities for cross‐disciplinary collaboration and learning. In particular, such forums are uniquely positioned to foster the sharing of three important components of research. First: they allow the sharing of conceptual frameworks for DII science that focus on the use and spread of innovations. Second: they provide an opportunity to share strategies for initiating and governing DII research, including approaches for eliciting and incorporating the research priorities of patients, study participants, and healthcare practitioners, and decision‐makers. Third: they allow the sharing of outcome measures well‐suited to the goals of DII science, thereby helping to validate these outcomes in diverse contexts, improving the comparability of findings across settings, and elevating the study of the implementation process itself.
We present a formally verified and executable on-the-fly LTL model checker that uses ample set partial order reduction. The verification is done using the proof assistant Isabelle/HOL and covers ...everything from the abstract correctness proof down to the generated SML code. Building on Doron Peled’s paper “Combining Partial Order Reductions with On-the-Fly Model-Checking”, we formally prove abstract correctness of ample set partial order reduction. This theorem is independent of the actual reduction algorithm. We then verify a reduction algorithm for a simple but expressive fragment of
Promela
. We use static partial order reduction, which allows separating the partial order reduction and the model checking algorithms regarding both the correctness proof and the implementation. Thus, the
Cava
model checker that we verified in previous work can be used as a back end with only minimal changes. Finally, we generate executable SML code using a stepwise refinement approach. We test our model checker on some examples, observing the effectiveness of the partial order reduction algorithm.
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