Isotopic effects on in-plane hyperbolic phonon polaritons in MoO3.

Hyperbolic phonon polaritons (HPhPs), hybrids of light and lattice vibrations in polar dielectric crystals, empower nanophotonic applications by enabling the confinement and manipulation of light at the nanoscale. Molybdenum trioxide (α-MoO3) is a naturally hyperbolic material, meaning that its dielectric function deterministically controls the directional propagation of in-plane HPhPs within its reststrahlen bands. Strategies such as substrate engineering, nano- and heterostructuring, and isotopic enrichment are being developed to alter the intrinsic die ectric functions of natural hyperbolic materials and to control the confinement and propagation of HPhPs. Since isotopic disorder can limit phonon-based processes such as HPhPs, here we synthesize isotopically enriched 92MoO3 (92Mo: 99.93 %) and 100MoO3 (100Mo: 99.01 %) crystals to tune the properties and dispersion of HPhPs with respect to natural α-MoO3, which is composed of seven stable Mo isotopes. Real-space, near-field maps measured with the photothermal induced resonance (PTIR) technique enable comparisons of inplane HPhPs in α-MoO3 and isotopically enriched analogues within a reststrahlen band (≈820 cm-1 to ≈ 972 cm-1). Results show that isotopic enrichment (e.g., 92MoO3 and 100MoO3) alters the dielectric function, shifting the HPhP dispersion (HPhP angular wavenumber × thickness vs IR frequency) by ≈-7% and ≈ +9 %, respectively, and changes the HPhP group velocities by ≈ ±12 %, while the lifetimes (≈ 3 ps) in 92MoO3 were found to be slightly improved (≈ 20 %). The latter improvement is attributed to a decrease in isotopic disorder. Altogether, isotopic enrichment was found to offer fine control over the properties that determine the anisotropic in-plane propagation of HPhPs in α-MoO3, which is essential to its implementation in nanophotonic applications.

Clinical, radiological and molecular responses to combination chemotherapy with MAPK pathway inhibition in relapsed and refractory Langerhans cell histiocytosis.

Optimal therapeutic approaches for advanced Langerhans cell histiocytosis (LCH) are not known. We assessed the safety and efficacy of combined chemotherapy with MAPK pathway inhibition in 10 patients with refractory systemic disease and/or LCH-associated neurodegeneration. Overall response rate was 9/10 (90%) for the entire cohort: 5/5 (100%) for patients with systemic disease and 6/7 (86%) for patients with central nervous system disease. BRAFV600E+ peripheral blood fraction decreased in 5/6 (83%). Toxicities included fever, skin rash, myalgias, neuropathy, cytopenias and hypocalcaemia. Prospective trials are required to optimize combination strategies, determine potential to achieve cure and compare outcomes to chemotherapy or MAPK inhibitor monotherapy.

Intussusception in Mosaic Trisomy 14.

Mosaic trisomy 14 is exceptionally rare and was first described in the 1970s with fewer than 100 known liveborn individuals. Information about complications and the natural history of the disease is rare, especially in adult patients. This case illustrates an adult patient with severe functional limitations from mosaic trisomy 14 who presented with abdominal pain and failure to thrive and was subsequently found to have intussusception and severe chronic constipation, which was successfully treated conservatively.

Diastolic dysfunction and clinical outcomes after transcatheter or surgical aortic valve replacement in patients with atypical aortic valve stenosis.

BACKGROUND: Diastolic dysfunction is a predictor of poor outcomes in many cardiovascular conditions. At present, it is unclear whether diastolic dysfunction predicts adverse outcomes in patients with atypical aortic stenosis who undergo aortic valve replacement (AVR). METHODS: Five hundred and twenty-three patients who underwent transcatheter AVR (TAVR) (n = 303) and surgical AVR (SAVR) (n = 220) at a single institution were included in our analysis. Baseline left and right heart invasive hemodynamics were assessed. Baseline transthoracic echocardiograms were reviewed to determine aortic stenosis subtype and parameters of diastolic dysfunction. Aortic stenosis subtype was categorized as typical (normal flow, high-gradient) aortic stenosis, classical, low-flow, low-gradient (cLFLG) aortic stenosis, and paradoxical, low-flow, low-gradient (pLFLG) aortic stenosis. Cox proportional hazard models were utilized to examine the relation between invasive hemodynamic or echocardiographic variables of diastolic dysfunction, aortic stenosis subtype, and all-cause mortality. Propensity-score analysis was performed to study the relation between aortic stenosis subtype and the composite outcome [death/cerebrovascular accident (CVA)]. RESULTS: The median STS risk was 5.3 and 2.5% for TAVR and SAVR patients, respectively. Relative to patients with typical aortic stenosis, patients with atypical (cLFLG and pLFLG) aortic stenosis displayed a significantly higher prevalence of diastolic dysfunction (LVEDP ≥ 20mmHg, PCWP ≥ 20mmHg, echo grade II or III diastolic dysfunction, and echo-PCWP ≥ 20mmHg) and, independently of AVR treatment modality, had a significantly increased risk of death. In propensity-score analysis, patients with atypical aortic stenosis had higher rates of death/CVA than typical aortic stenosis patients, independently of diastolic dysfunction and AVR treatment modality. CONCLUSION: We demonstrate the novel observation that compared with patients with typical aortic stenosis, patients with atypical aortic stenosis have a higher burden of diastolic dysfunction. We corroborate the worse outcomes previously reported in atypical versus typical aortic stenosis and demonstrate, for the first time, that this observation is independent of AVR treatment modality. Furthermore, the presence of diastolic dysfunction does not independently predict outcome in atypical aortic stenosis regardless of treatment type, suggesting that other factors are responsible for adverse clinical outcomes in this higher risk cohort.

Pseudocoarctation following elephant trunk intervention.

We describe the case of a 55-year-old man with a pseudocoarctation of the descending aorta following a conventional elephant trunk technique. The patient underwent aortic arch replacement with the conventional elephant trunk technique. After the operation, he had developed an increasing creatinine level, hemolysis, and cyanosis of his toes. Femoral arterial line placement confirmed a 50-mm Hg systolic pressure gradient between his radial and femoral arteries. Computed tomography angiography revealed that the elephant trunk graft within the true lumen was compressed, resulting in a pseudocoarctation. The patient was successfully treated with thoracic endovascular aneurysm repair.

Capillary Leak syndrome within an hour of G-CSF.

Capillary leak syndrome (CLS) is a well-known phenomenon that has been reported commonly in association with septic shock, polytrauma, and pancreatitis in intensive care settings. In the hematologic literature, it has been reported following granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor, tumor necrosis factor, interleukin 2, and interleukin 4 infusions; and autologous and allogenic bone marrow transplantations in both pediatric as well as adult populations. Only a few cases of CLS have been reported in the pediatric population following G-CSF. We report here a case of a 9-year-old female who developed CLS within 60 minutes of receiving the first dose of G-CSF that was successfully treated with immediate symptomatic management.

Open-Spaced Ridged Hydrogel Scaffolds Containing TiO2-Self-Assembled Monolayer of Phosphonates Promote Regeneration and Recovery Following Spinal Cord Injury.

The spinal cord has a poor ability to regenerate after an injury, which may be due to cell loss, cyst formation, inflammation, and scarring. A promising approach to treating a spinal cord injury (SCI) is the use of biomaterials. We have developed a novel hydrogel scaffold fabricated from oligo(poly(ethylene glycol) fumarate) (OPF) as a 0.08 mm thick sheet containing polymer ridges and a cell-attractive surface on the other side. When the cells are cultured on OPF via chemical patterning, the cells attach, align, and deposit ECM along the direction of the pattern. Animals implanted with the rolled scaffold sheets had greater hindlimb recovery compared to that of the multichannel scaffold control, which is likely due to the greater number of axons growing across it. The immune cell number (microglia or hemopoietic cells: 50-120 cells/mm2 in all conditions), scarring (5-10% in all conditions), and ECM deposits (Laminin or Fibronectin: approximately 10-20% in all conditions) were equal in all conditions. Overall, the results suggest that the scaffold sheets promote axon outgrowth that can be guided across the scaffold, thereby promoting hindlimb recovery. This study provides a hydrogel scaffold construct that can be used in vitro for cell characterization or in vivo for future neuroprosthetics, devices, or cell and ECM delivery.

Triiodide Attacks the Organic Cation in Hybrid Lead Halide Perovskites: Mechanism and Suppression.

Molecular I2 can be produced from iodide-based lead perovskites under thermal stress; triiodide, I3 - , is formed from this I2 and I- . Triiodide attacks protic cation MA+ - or FA+ -based lead halide perovskites (MA+ , methylammonium; FA+ , formamidinium) as explicated through solution-based nuclear magnetic resonance (NMR) studies: triiodide has strong hydrogen-bonding affinity for MA+ or FA+ , which leads to their deprotonation and perovskite decomposition. Triiodide is a catalyst for this decomposition that can be obviated through perovskite surface treatment with thiol reducing agents. In contrast to methods using thiol incorporation into perovskite precursor solutions, no penetration of the thiol into the bulk perovskite is observed, yet its surface application stabilizes the perovskite against triiodide-mediated thermal stress. Thiol applied to the interface between FAPbI3 and Spiro-OMeTAD ("Spiro") prevents oxidized iodine species penetration into Spiro and thus preserves its hole-transport efficacy. Surface-applied thiol affects the perovskite work function; it ameliorates hole injection into the Spiro overlayer, thus improving device performance. It helps to increase interfacial adhesion ("wetting"): fewer voids are observed at the Spiro/perovskite interface if thiols are applied. Perovskite solar cells (PSCs) incorporating interfacial thiol treatment maintain over 80% of their initial power conversion efficiency (PCE) after 300 h of 85 °C thermal stress.

Beating thermal noise in a dynamic signal measurement by a nanofabricated cavity optomechanical sensor.

Thermal fluctuations often impose both fundamental and practical measurement limits on high-performance sensors, motivating the development of techniques that bypass the limitations imposed by thermal noise outside cryogenic environments. Here, we theoretically propose and experimentally demonstrate a measurement method that reduces the effective transducer temperature and improves the measurement precision of a dynamic impulse response signal. Thermal noise-limited, integrated cavity optomechanical atomic force microscopy probes are used in a photothermal-induced resonance measurement to demonstrate an effective temperature reduction by a factor of ≈25, i.e., from room temperature down as low as ≈12 K, without cryogens. The method improves the experimental measurement precision and throughput by >2×, approaching the theoretical limit of ≈3.5× improvement for our experimental conditions. The general applicability of this method to dynamic measurements leveraging thermal noise-limited harmonic transducers will have a broad impact across a variety of measurement platforms and scientific fields.

Understanding Cantilever Transduction Efficiency and Spatial Resolution in Nanoscale Infrared Microscopy.

Photothermal induced resonance (PTIR), also known as AFM-IR, enables nanoscale infrared (IR) imaging and spectroscopy by using the tip of an atomic force microscope to transduce the local photothermal expansion and contraction of a sample. The signal transduction efficiency and spatial resolution of PTIR depend on a multitude of sample, cantilever, and illumination source parameters in ways that are not yet well understood. Here, we elucidate and separate the effects of laser pulse length, pulse shape, sample thermalization time (τ), interfacial thermal conductance, and cantilever detection frequency by devising analytical and numerical models that link a sample's photothermal excitations to the cantilever dynamics over a broad bandwidth (10 MHz). The models indicate that shorter laser pulses excite probe oscillations over broader bandwidths and should be preferred for measuring samples with shorter thermalization times. Furthermore, we show that the spatial resolution critically depends on the interfacial thermal conductance between dissimilar materials and improves monotonically, but not linearly, with increasing cantilever detection frequencies. The resolution can be enhanced for samples that do not fully thermalize between pulses (i.e., laser repetition rates ≳ 1/3τ) as the probed depth becomes smaller than the film thickness. We believe that the insights presented here will accelerate the adoption and impact of PTIR analyses across a wide range of applications by informing experimental designs and measurement strategies as well as by guiding future technical advances.

Prenatal presentation of an adrenocortical tumor.

BACKGROUND: Prenatally identified suprarenal masses are most often found to be adrenal hemorrhage. The most common tumor in this situation is neuroblastoma. CASE PRESENTATION: We report the case of a rare adrenocortical tumor found prenatally on ultrasound. While most patients with adrenocortical tumors present with virilizing symptoms, our patient did not have evidence of virilization and was presumed to have neuroblastoma. CONCLUSION: Following a period of observation, our patient underwent surgical resection due to tumor growth revealing the unexpected diagnosis.

Untying the Cesium "Not": Cesium-Iodoplumbate Complexation in Perovskite Solution-Processing Inks Has Implications for Crystallization.

We illustrate the critical importance of the energetics of cation-solvent versus cation-iodoplumbate interactions in determining the stability of ABX3 perovskite precursors in a dimethylformamide (DMF) solvent medium. We have shown, through a complementary suite of nuclear magnetic resonance (NMR) and computational studies, that Cs+ exhibits significantly different solvent vs iodoplumbate interactions compared to organic A+-site cations such as CH3NH3+ (MA+). Two NMR studies were conducted: 133Cs NMR analysis shows that Cs+ and MA+ compete for coordination with PbI3- in DMF. 207Pb NMR studies of PbI2 with cationic iodides show that perovskite-forming Cs+ (and, somewhat, Rb+) do not comport with the 207Pb chemical shift trend found for Li+, Na+, and K+. Three independent computational approaches (density functional theory (DFT), ab initio Molecular Dynamics (AIMD), and a polarizable force field within Molecular Dynamics) yielded strikingly similar results: Cs+ interacts more strongly with the PbI3- iodoplumbate than does MA+ in a polar solvent environment like DMF. The stronger energy preference for PbI3- coordination of Cs+ vs MA+ in DMF demonstrates that Cs+ is not simply a postcrystallization cation "fit" for the perovskite A+-site. Instead, it may facilitate preorganization of the framework precursor that eventually transforms into the crystalline perovskite structure.

Comprehensive National Inpatient Sample data reveals low but rising Pneumocystis jiroveci pneumonia risk in inflammatory bowel disease patients.

Background: There are only limited data to guide the management of infectious risk for Pneumocystis jiroveci pneumonia (PCP) in patients with inflammatory bowel disease (IBD). We evaluated the frequency of admissions for PCP among patients with IBD, as well as the temporal trend in PCP admission rates and the contribution of non-IBD risk factors to the development of infection. Methods: The National Inpatient Sample from 2016-2017 was queried for all admissions involving both PCP and either Crohn's disease or ulcerative colitis. Inpatient outcomes associated with PCP and additive risk factors for development of PCP within the IBD patient population were assessed using multivariate regression. Linear regression was performed on data from 2002-2017 to measure infectious trends over time. Results: There were an estimated 225 admissions involving PCP among patients with IBD from 2016-2017 nationwide, representing 0.035% of total admissions. IBD patients with PCP faced a 4.67-fold higher adjusted odds of inpatient mortality (95% confidence interval 1.72-12.66), while 49% of patients with IBD who developed PCP had an unrelated risk factor. The most common factors were HIV and congenital immunodeficiency, both of which were associated with PCP in adjusted regression. The infectious incidence of PCP increased by 141% from 2002 to 2017 (P=0.003). Conclusions: National admissions data indicate that significant PCP is rare in IBD patients. Routine PCP prophylaxis is probably not necessary, although further study of high-risk subgroups of patients is required. The rising incidence of PCP indicates a need for continued surveillance.

High Throughput Nanoimaging of Thermal Conductivity and Interfacial Thermal Conductance.

Thermal properties of materials are often determined by measuring thermalization processes; however, such measurements at the nanoscale are challenging because they require high sensitivity concurrently with high temporal and spatial resolutions. Here, we develop an optomechanical cantilever probe and customize an atomic force microscope with low detection noise ≈1 fm/Hz1/2 over a wide (>100 MHz) bandwidth that measures thermalization dynamics with ≈10 ns temporal resolution, ≈35 nm spatial resolution, and high sensitivity. This setup enables fast nanoimaging of thermal conductivity (η) and interfacial thermal conductance (G) with measurement throughputs ≈6000× faster than conventional macroscale-resolution time-domain thermoreflectance acquiring the full sample thermalization. As a proof-of-principle demonstration, 100 × 100 pixel maps of η and G of a polymer particle are obtained in 200 s with a small relative uncertainty (<10%). This work paves the way to study fast thermal dynamics in materials and devices at the nanoscale.

A guide to nanoscale IR spectroscopy: resonance enhanced transduction in contact and tapping mode AFM-IR.

Infrared (IR) spectroscopy is a broadly applicable, composition sensitive analytical technique. By leveraging the high spatial resolution of atomic force microscopy (AFM), the photothermal effect, and wavelength-tunable lasers, AFM-IR enables IR spectroscopy and imaging with nanoscale (< 10 nm) resolution. The transduction of a sample's photothermal expansion by an AFM probe tip ensures the proportionality between the AFM-IR signal and the sample absorption coefficient, producing images and spectra that are comparable to far-field IR databases and easily interpreted. This convergence of characteristics has spurred robust research efforts to extend AFM-IR capabilities and, in parallel, has enabled AFM-IR to impact numerous fields. In this tutorial review, we present the latest technical breakthroughs in AFM-IR spectroscopy and imaging and discuss its working principles, distinctive characteristics, and best practices for different AFM-IR measurement paradigms. Central to this review, appealing to both expert practitioners and novices alike, is the meticulous understanding of AFM-IR signal transduction, which is essential to take full advantage of AFM-IR capabilities. Here, we critically compile key information and discuss instructive experiments detailing AFM-IR signal transduction and provide guidelines linking experimental parameters to the measurement sensitivity, lateral resolution, and probed depth. Additionally, we provide in-depth tutorials on the most employed AFM-IR variants (resonance-enhanced and tapping mode AFM-IR), discussing technical details and representative applications. Finally, we briefly review recently developed AFM-IR modalities (peak force tapping IR and surface sensitivity mode) and provide insights on the next exciting opportunities and prospects for this fast-growing and evolving field.

Cracking the Hip: Does Protocol Matter? A Retrospective Cohort Study Investigating the Effect of Protocol Implementation.

INTRODUCTION: Approximately 300 000 hip fractures occur annually in the USA in patients >65 years old. Early intervention is key in reducing morbidity and mortality. Our institution implemented a collaborative hip fracture protocol, streamlining existing processes to reduce time to OR (TTO) and hospital length of stay (LOS). Our aim was to determine if this protocol improved these outcomes. STUDY DESIGN: We conducted a retrospective cohort study using our level-1 trauma center's trauma registry, comparing outcomes for patients >60 years old with isolated hip fractures pre-and post-hip protocol implementation in May 2018. Our primary outcomes were TTO and in-hospital mortality. Secondary outcomes included LOS and postoperative complications. Univariate analysis was done using chi-square and T-test. RESULTS: We identified 176 patients with isolated hip fractures: 69 post- and 107 pre-protocol. Comparing post- to pre-protocol, TTO decreased by 18hrs (39 vs 57h; P = .013) and patients had fewer postoperative complications (9 vs 23%; P = .016) despite post-protocol patients being more likely to have diabetes (42 vs 27%, P < .05), elevated BMI (22 vs 25; P < .001), and to be current smokers (9 vs 2%; P < .05). LOS and in-hospital mortality also decreased (11 vs 20d; P = .312, 4.3 vs 7.5%; P = .402). Post-protocol patients were more likely to go to the OR within 24hrs of presentation (39 vs 16%; P < .001) and to go straight from ED to OR (32 vs 4%; P < .001). CONCLUSION: TTO, LOS, and postoperative complications for isolated hip fracture patients were lower post-protocol. Though not all statistically significant, this trend indicates that the protocol was helpful in improving hip fracture outcomes but may require further improvement and institution-wide education.

Micro to Nano: Multiscale IR Analyses Reveal Zinc Soap Heterogeneity in a 19th-Century Painting by Corot.

Formation and aggregation of metal carboxylates (metal soaps) can degrade the appearance and integrity of oil paints, challenging efforts to conserve painted works of art. Endeavors to understand the root cause of metal soap formation have been hampered by the limited spatial resolution of Fourier transform infrared microscopy (µ-FTIR). We overcome this limitation using optical photothermal infrared spectroscopy (O-PTIR) and photothermal-induced resonance (PTIR), two novel methods that provide IR spectra with ≈500 and ≈10 nm spatial resolutions, respectively. The distribution of chemical phases in thin sections from the top layer of a 19th-century painting is investigated at multiple scales (µ-FTIR ≈ 102 µm3, O-PTIR ≈ 10-1 µm3, PTIR ≈ 10-5 µm3). The paint samples analyzed here are found to be mixtures of pigments (cobalt green, lead white), cured oil, and a rich array of intermixed, small (often ≪ 0.1 µm3) zinc soap domains. We identify Zn stearate and Zn oleate crystalline soaps with characteristic narrow IR peaks (≈1530-1558 cm-1) and a heterogeneous, disordered, water-permeable, tetrahedral zinc soap phase, with a characteristic broad peak centered at ≈1596 cm-1. We show that the high signal-to-noise ratio and spatial resolution afforded by O-PTIR are ideal for identifying phase-separated (or locally concentrated) species with low average concentration, while PTIR provides an unprecedented nanoscale view of distributions and associations of species in paint. This newly accessible nanocompositional information will advance our knowledge of chemical processes in oil paint and will stimulate new art conservation practices.

High Rates of Mortality in Geriatric Patients Admitted for Inflammatory Bowel Disease Management.

GOAL: The goal of this study was to evaluate the inpatient mortality risk among geriatric patients with inflammatory bowel disease (IBD). BACKGROUND: The challenges of caring for elderly patients with IBD will increase with the aging of the US population. Given the complications of hospitalization, we set to examine if elderly patients age older than 65 were at higher risk of mortality. MATERIALS AND METHODS: All patients with ulcerative colitis (UC) or Crohn's disease (CD) in the National Inpatient Sample (NIS) from 2016 and 2017 as the primary diagnosis or secondary diagnosis with an IBD-related cause of admission were included. Outcomes for patients aged above 65 were compared with below 65 using multivariable survey-adjusted regression. CD and UC were analyzed separately. RESULTS: In 2016-2017, there were an estimated 162,800 admissions for CD and related complications compared with 96,450 for UC. In total, 30% of UC and 20% of CD admissions were geriatric. Geriatric status was associated with higher odds of mortality for CD [odds ratio (OR)=3.47, 95% confidence interval (CI): 2.72-4.44] and UC (OR=2.75, 95% CI: 2.16-3.49) after adjustment for comorbidities, admission type, hospital type, inpatient surgery, and IBD subtype. The cause of death was ∼80% infectious in both CD and UC in all groups. An average of 0.19 days (95% CI: 0.05-0.34) and $2467 (95% CI: 545-4388) increase was seen for geriatric CD patients. No significant change was seen for UC. CONCLUSIONS: Age over 65 was independently associated with higher odds of death in both UC and CD patients, even after appropriate adjustment. Further research is needed to optimize care for this growing patient population.