One-Pot Self-Assembly of Sequence-Controlled Mesoporous Heterostructures via Structure-Directing Agents.

Multimaterial heterostructures have led to characteristics surpassing the individual components. Nature controls the architecture and placement of multiple materials through biomineralization of nanoparticles (NPs); however, synthetic heterostructure formation remains limited and generally departs from the elegance of self-assembly. Here, a class of block polymer structure-directing agents (SDAs) are developed containing repeat units capable of persistent (covalent) NP interactions that enable the direct fabrication of nanoscale porous heterostructures, where a single material is localized at the pore surface as a continuous layer. This SDA binding motif (design rule 1) enables sequence-controlled heterostructures, where the composition profile and interfaces correspond to the synthetic addition order. This approach is generalized with 5 material sequences using an SDA with only persistent SDA-NP interactions ("P-NP1-NP2"; NPi = TiO2, Nb2O5, ZrO2). Expanding these polymer SDA design guidelines, it is shown that the combination of both persistent and dynamic (noncovalent) SDA-NP interactions ("PD-NP1-NP2") improves the production of uniform interconnected porosity (design rule 2). The resulting competitive binding between two segments of the SDA (P- vs D-) requires additional time for the first NP type (NP1) to reach and covalently attach to the SDA (design rule 3). The combination of these three design rules enables the direct self-assembly of heterostructures that localize a single material at the pore surface while preserving continuous porosity.

Unimer suppression enables supersaturated homopolymer swollen micelles with long-term stability after glassy entrapment.

Micelle sizes are critical for a range of applications where the simple ability to adjust and lock in specific stable sizes has remained largely elusive. While micelle swelling agents are well-known, their dynamic re-equilibration in solution implies limited stability. Here, a non-equilibrium processing sequence is studied where supersaturated homopolymer swelling is combined with glassy-core ("persistent") micelles. This path-dependent process was found to sensitively depend on unimer concentration as revealed by DLS, SAXS, and TEM analysis. Here, lower-selectivity solvent combinations led to the formation of unimer-homopolymer aggregates and eventual precipitation, reminiscent of anomalous micellization. In contrast, higher-selectivity solvents enabled supersaturated homopolymer loadings favored by rapid homopolymer insertion. The demonstrated ∼40-130 nm core-size tuning exceeded prior equilibrium demonstrations and subsequent core-vitrification enabled size persistence beyond 6 months. Lastly, the linear change in micelle diameter with homopolymer addition was found to correlate with a plateau in the interfacial area per copolymer chain.

INTRAOPERATIVE BLEB BEHAVIOR IN SUBRETINAL GENE AUGMENTATION THERAPY FOR INHERITED RETINAL DISEASES.

PURPOSE: In subretinal gene therapy for inherited retinal diseases (IRDs), blebs may not propagate predictably in the direction of the injection cannula. We evaluated factors that influenced bleb propagation among various IRDs. METHODS: Retrospective review of all subretinal gene therapy procedures performed by a single surgeon between September 2018 and March 2020 for various IRDs. Main outcome measures were directional bias of bleb propagation and intraoperative foveal detachment. RESULTS: Desired injection volumes and/or foveal treatment were successfully achieved in all 70 eyes of 46 patients with IRD regardless of IRD indication. Bullous foveal detachment was associated with retinotomy closer to the fovea, posterior bleb bias, and greater bleb volumes ( P < 0.01). Blebs biased anteriorly or posteriorly based on disease indication ( P = 0.04) and age ( P < 0.001). Retinotomy location ≤ 3.7 mm (approximately two disk diameters) from the fovea favored foveal detachment ( P < 0.001). Multiple retinotomies and blebs allowed greater surface area coverage in some eyes, but intersecting blebs did not propagate further. CONCLUSION: Bleb formation and propagation are predictable based on patient age, retinotomy location, disease indication, and how tangentially fluid is directed into the subretinal space.

Uses and Considerations for Cinematic Virtual Reality in Health Care.

BACKGROUND: Through the combination of virtual reality (VR) technology with techniques from theater, filmmaking, and gaming, individuals from the Game Research and Immersive Design Laboratory (GRID Lab) at Ohio University have developed an approach to train soft skills such as communication, problem-solving, teamwork, and interpersonal skills which shows great promise. OBJECTIVES: The purpose of this article is to provide an overview of VR and cinematic-VR (cine-VR). This article serves as a preface to the VR research included in this special issue. METHODS: In this article, we define VR, review key terminology, present a case study, and offer future directions. RESULTS: Prior research with cine-VR has demonstrated the effectiveness in improving provider attitudes and cultural self-efficacy. While cine-VR may differ from other types of VR applications, we have been able to leverage the strengths of cine-VR to create training programs which are user friendly and highly effective. Early projects on diabetes care and opioid use disorder were sufficiently successful that the team received additional funding to pursue series addressing elder abuse/neglect and intimate partner violence. Their work has gone beyond health care and is currently being leveraged for law enforcement training as well. While this article will explore Ohio University's approach to cine-VR training, details of their research including efficacy can be found in McCalla et al, Wardian et al, and Beverly et al. CONCLUSION: When produced correctly, cine-VR has the potential to become a mainstay component of training for soft skill applications across a multitude of industries.

Enhanced Structural Control of Soft-Templated Mesoporous Inorganic Thin Films by Inert Processing Conditions.

Mesoporous thin films are widely used for applications in need of high surface area and efficient mass and charge transport properties. A well-established fabrication process involves the supramolecular assembly of organic molecules (e.g., block copolymers and surfactants) with inorganic materials obtained by sol-gel chemistry. Typically, subsequent calcination in air removes the organic template and reveals the porous inorganic network. A significant challenge for such coatings is the anisotropic shrinkage due to the volume contraction related to solvent evaporation, inorganic condensation, and template removal, affecting the final porosity as well as pore shape, size, arrangement, and accessibility. Here, we show that a two-step calcination process, composed of high-temperature treatment in argon followed by air calcination, is an effective fabrication strategy to reduce film contraction and enhance structural control of mesoporous thin films. Crucially, the formation of a transient carbonaceous scaffold enables the inorganic matrix to fully condense before template removal. The resulting mesoporous films retain a higher porosity as well as bigger pores with extended porous order. Such films present favorable characteristics for mass transport of large molecules. This is demonstrated for lysozyme adsorption into the mesoporous thin films as an example of enzyme storage.

High-χ, low-N micelles from partially perfluorinated block polymers.

Kinetically trapped ("persistent") micelles enable emerging applications requiring a constant core diameter. Preserving a χN barrier to chain exchange with low-N requires a commensurately higher χcore-solvent for micelle persistence. Low-N, high-χ micelles containing fluorophobic interactions were studied using poly(ethylene oxide-b-perfluorooctyl acrylate)s (O45FX, x = 8, 11) in methanolic solutions. DLS analysis of micelles revealed chain exchange only for O45F8 while SAXS analysis suggested elongated core block conformations commensurate with the contour lengths. Micelle chain exchange from solution perturbations were examined by characterizing their behavior as templates for inorganic materials via SAXS and SEM. In contrast to the F8 analog, the larger χN barrier for the O45F11 enabled persistent micelle behavior in both thin films and bulk samples despite the low Tg micelle core. Careful measures of micelle core diameters and pore sizes revealed that the nanoparticle distribution extended through the corona and 0.52 ± 0.15 nm into the core-corona interface, highlighting thermodynamics favoring both locations simultaneously.

Mesoporous TiO2 Microparticles with Tailored Surfaces, Pores, Walls, and Particle Dimensions Using Persistent Micelle Templates.

Mesoporous microparticles are an attractive platform to deploy high-surface-area nanomaterials in a convenient particulate form that is broadly compatible with diverse device manufacturing methods. The applications for mesoporous microparticles are numerous, spanning the gamut from drug delivery to catalysis and energy storage. For most applications, the performance of the resulting materials depends upon the architectural dimensions including the mesopore size, wall thickness, and microparticle size, yet a synthetic method to control all these parameters has remained elusive. Furthermore, some mesoporous microparticle reports noted a surface skin layer which has not been tuned before despite the important effect of such a skin layer upon transport/encapsulation. In the present study, material precursors and block polymer micelles are combined to yield mesoporous materials in a microparticle format due to phase separation from a homopolymer matrix. The skin layer thickness was kinetically controlled where a layer integration via diffusion (LID) model explains its production and dissipation. Furthermore, the independent tuning of pore size and wall thickness for mesoporous microparticles is shown for the first time using persistent micelle templates (PMT). Last, the kinetic effects of numerous processing parameters upon the microparticle size are shown.

Fibrotic cataract as a sign of posterior capsule violation post vitrectomy.

PURPOSE: To report fibrotic cataract as a sign of posterior capsule violation post vitrectomy. OBSERVATIONS: A 16 year old female presented to our retina clinic after multiple prior vitrectomies at an outside hospital for traumatic retinal detachment. On presentation, it was noted that she still had a silicone oil inside the eye, and a dense, fibrotic cataract limiting the posterior pole view. The decision was made to pursue cataract phacoemulsification plus silicone oil removal. We utilized the Zepto capsulotomy system given the white cataract. After gentle bimanual irrigation and aspiration of the cataract, it was discovered there were two small, round, posterior capsule defects with fibrosis around these holes that extended anteriorly, involving the capsular fornix and anterior capsule. This was confirmed intraoperatively on heads-up OCT. A three-piece intraocular lens was placed into the capsular bag, but given the contracted capsular fornix, the IOL was decentered inferonasally, so it was repositioned in the sulcus with good centration. CONCLUSIONS: It is known that pars plana vitrectomy leads to accelerated cataract formation postoperatively. This case report is the first to our knowledge that describes a fibrotic cataract as a sign of posterior capsular violation. IMPORTANCE: We demonstrate that presence of fibrotic cataract post vitrectomy should raise suspicion for capsular violation and should prompt further discussion with the patient regarding appropriate surgical planning and expectations.

Iris manipulation during phacoemulsification: intraoperative and postoperative complications.

AIM: To quantify intraoperative and postoperative complications in complex phacoemulsification cataract extraction (phacoemulsification) with iris manipulation compared to non-complex and complex phacoemulsification without iris manipulation. METHODS: All phacoemulsification cases at the University of Colorado between January 1, 2014, and June 30, 2017 were included. Exclusion criteria for the primary outcome of intraoperative complications were planned combination surgery and eyes with less than 28d follow-up. Exclusion criteria for the secondary outcomes of postoperative complications were unplanned additional surgery, and chronic steroid eye drop use prior to surgery. Data including sex, race/ethnicity, surgery length, visual acuity, intraoperative and postoperative complications, and intraocular pressures (IOP) were collected and analyzed utilizing general linear and Logistic regression modeling. RESULTS: The medical records of 5772 eyes were reviewed (500 complex without iris manipulation, 367 with iris manipulation). The number of any intraoperative complication in the complex with iris manipulation and complex without iris manipulation groups was 15 (4.1%) and 26 (5.2%), respectively, compared to 41 (0.8%) in the non-complex group. Postoperative inflammation was found in 135 (2.8%) non-complex cases, 20 (4.1%) complex cases without iris manipulation, and 20 (5.6%) complex cases with iris manipulation. The adjusted odds ratio of postoperative inflammation in phacoemulsification with iris manipulation compared to non-complex was 2.3 (95%CI: 1.3-4.0, P=0.005). The rate of IOP spikes >10 mm Hg was significantly greater in cases with iris manipulation (P=0.001). CONCLUSION: Complex cases have more intraoperative complications. However, only complex cases with iris manipulation led to increase rates of postoperative inflammation and IOP spikes >10 mm Hg.

Multiple-Choice Tests: A-Z in Best Writing Practices.

Multiple-choice tests are the most used method of assessment in medical education. However, there is limited literature in medical education and psychiatry to inform the best practices in writing good-quality multiple-choice questions. Moreover, few physicians and psychiatrists have received training and have experience in writing them. This article highlights the strategies in writing high-quality multiple-choice items and discusses some common flaws that can impact validity and reliability of the assessment examinations.

Effect of Membrane Properties on the Carbonation of Anion Exchange Membrane Fuel Cells.

Anion exchange membrane fuel cells (AEMFC) are potentially very low-cost replacements for proton exchange membrane fuel cells. However, AEMFCs suffer from one very serious drawback: significant performance loss when CO2 is present in the reacting oxidant gas (e.g., air) due to carbonation. Although the chemical mechanisms for how carbonation leads to voltage loss in operating AEMFCs are known, the way those mechanisms are affected by the properties of the anion exchange membrane (AEM) has not been elucidated. Therefore, this work studies AEMFC carbonation using numerous high-functioning AEMs from the literature and it was found that the ionic conductivity of the AEM plays the most critical role in the CO2-related voltage loss from carbonation, with the degree of AEM crystallinity playing a minor role. In short, higher conductivity-resulting either from a reduction in the membrane thickness or a change in the polymer chemistry-results in faster CO2 migration and emission from the anode side. Although this does lead to a lower overall degree of carbonation in the polymer, it also increases CO2-related voltage loss. Additionally, an operando neutron imaging cell is used to show that as AEMFCs become increasingly carbonated their water content is reduced, which further drives down cell performance.

Developing Virtual Reality Trauma Training Experiences Using 360-Degree Video: Tutorial.

Historically, medical trainees were educated in the hospital on real patients. Over the last decade, there has been a shift to practicing skills through simulations with mannequins or patient actors. Virtual reality (VR), and in particular, the use of 360-degree video and audio (cineVR), is the next-generation advancement in medical simulation that has novel applications to augment clinical skill practice, empathy building, and team training. In this paper, we describe methods to design and develop a cineVR medical education curriculum for trauma care training using real patient care scenarios at an urban, safety-net hospital and Level 1 trauma center. The purpose of this publication is to detail the process of finding a cineVR production partner; choosing the camera perspectives; maintaining patient, provider, and staff privacy; ensuring data security; executing the cineVR production process; and building the curriculum.

Controlled Dimerization of Mn12 Single-Molecule Magnets.

Controlled dimerization of Mn12 single-molecule magnets (SMMs) was achieved via a synthetic route involving a competition between bridging and terminal ligands, namely, diols and alcohols. The reaction using a 1:1 ratio of the competing ligands resulted in the isolation of a new family of covalently linked dimers of Mn12 SMMs. This is the first step toward the controlled growth of SMM oligomeric arrays.

A Leadless Intracardiac Transcatheter Pacing System.

BACKGROUND: A leadless intracardiac transcatheter pacing system has been designed to avoid the need for a pacemaker pocket and transvenous lead. METHODS: In a prospective multicenter study without controls, a transcatheter pacemaker was implanted in patients who had guideline-based indications for ventricular pacing. The analysis of the primary end points began when 300 patients reached 6 months of follow-up. The primary safety end point was freedom from system-related or procedure-related major complications. The primary efficacy end point was the percentage of patients with low and stable pacing capture thresholds at 6 months (≤2.0 V at a pulse width of 0.24 msec and an increase of ≤1.5 V from the time of implantation). The safety and efficacy end points were evaluated against performance goals (based on historical data) of 83% and 80%, respectively. We also performed a post hoc analysis in which the rates of major complications were compared with those in a control cohort of 2667 patients with transvenous pacemakers from six previously published studies. RESULTS: The device was successfully implanted in 719 of 725 patients (99.2%). The Kaplan-Meier estimate of the rate of the primary safety end point was 96.0% (95% confidence interval [CI], 93.9 to 97.3; P<0.001 for the comparison with the safety performance goal of 83%); there were 28 major complications in 25 of 725 patients, and no dislodgements. The rate of the primary efficacy end point was 98.3% (95% CI, 96.1 to 99.5; P<0.001 for the comparison with the efficacy performance goal of 80%) among 292 of 297 patients with paired 6-month data. Although there were 28 major complications in 25 patients, patients with transcatheter pacemakers had significantly fewer major complications than did the control patients (hazard ratio, 0.49; 95% CI, 0.33 to 0.75; P=0.001). CONCLUSIONS: In this historical comparison study, the transcatheter pacemaker met the prespecified safety and efficacy goals; it had a safety profile similar to that of a transvenous system while providing low and stable pacing thresholds. (Funded by Medtronic; Micra Transcatheter Pacing Study ClinicalTrials.gov number, NCT02004873.).