The addition of Pd to Pt-based diesel oxidation catalysts is known to enhance performance and restrict the anomalous growth of Pt nanoparticles when subjected to aging at high temperatures in ...oxidative environments. Here, to gain a mechanistic understanding, we studied the transport of the mobile Pt and Pd species to the vapor phase, since vapor phase transport is the primary route for sintering in these catalysts. The results are surprising: there is a 30-fold drop in the effective vapor pressure of Pt in the Pt-Pd catalysts compared to monometallic Pt. At the same time, there is a significant enhancement in the vapor pressure of Pd, compared to PdO, which otherwise has a negligible vapor pressure at the aging temperature. Such behavior cannot be explained simply by alloying Pt and Pd in the metallic phase, or a core-shell morphology where a PdO shell covers a Pt core. Transmission electron microscopic examination of catalysts aged up to 50 h in air at 800 °C shows that the particles exhibit a biphasic “Janus”-like structure. The metal and oxide phases are conjoined, exposing a metal and an oxide face to the gas phase. The high mobility of the Pt and Pd allows them to be partitioned into the metal and oxide phases, in apparent thermodynamic equilibrium. The PdO helps to trap mobile PtO2 and as a result contains high concentrations of Pt oxide, consistent with its role in mitigating the transport of Pt to the vapor phase and preventing the growth of anomalously large particles. In turn, Pt allows Pd to remain metallic, allowing the catalyst to retain both metal and oxide functionality for catalysis. The regeneration of deactivated catalysts typically requires an external input, such as a change in the working environment from reducing to oxidizing or vice-versa. Here, we show that the mobile species, which are primary contributors to catalyst sintering are effectively returned to the active site, hence our use of the term “selfhealing”. The detailed insights into the inner workings of the Pt-Pd diesel oxidation catalysts can help provide clues to the design of robust and durable heterogeneous catalysts.
A deed executed in 1828 by an Americo-Liberian settler and four African kings procured for the American Society for Colonizing the Free People of Color of the United States the territory that would ...become the nucleus of the Republic of Liberia. The deed was published in an American periodical in 1828, but in a manner that changed its meaning and significance. The current transcription returns to the document that was sent from Monrovia to Washington, D.C., in 1828. It is significant for scholars since all who have analyzed it have used the periodical publication. It is significant for Liberian history since, by its conveyance to the U.S., it was saved from the destruction of the Liberian National Archives that occurred in the 1990s, during the civil war.
Despite guidelines to the contrary, limited numbers of elective percutaneous coronary intervention (PCI) procedures without on-site surgical backup are being performed, particularly in Europe and ...Canada. In the United States, many hospitals are considering establishing on-site surgical programs, in part to facilitate PCI. At a hospital with only off-site surgical backup, 562 elective PCI procedures were performed on 489 consecutive patients. Of these, 551 (98.0%) were successfully completed without major in-hospital complications; 5 patients (1.0%) had in-hospital complications, and 4 (0.8%) were urgently transferred. It is concluded that elective PCI with off-site surgical backup is feasible and safe for selected patients under specific conditions.
TPS4204
Background: The role of neoadjuvant chemotherapy in resectable pancreatic cancer has yet to be defined. Recent phase II trial results demonstrate a median overall survival time (mOS) of only ...22.4 months after treatment with perioperative modified FOLFIRINOX (mFOLFIRINOX) with 36% not reaching surgery due to disease progression during neoadjuvant therapy. While potential benefits and shortcomings of neoadjuvant chemotherapy have been well documented, to date, no phase III trial has directly compared a perioperative versus an adjuvant chemotherapy strategy in resectable pancreatic cancer. Alliance for Clinical Trials in Oncology A021806 is an actively accruing randomized controlled phase III trial evaluating the efficacy of perioperative chemotherapy with mFOLFIRINOX in patients with resectable pancreatic cancer. Methods: To qualify for enrollment, patients must have biopsy-proven localized resectable pancreatic adenocarcinoma as defined by the National Comprehensive Cancer Network. Patients must have good performance status (ECOG 0 or 1) and be candidates to receive mFOLFIRINOX treatment. All patients enrolled undergo central radiologic eligibility review for quality control and are then randomized to either Arm 1 which consists of 8 cycles of neoadjuvant mFOLFIRINOX followed by 4 cycles of adjuvant mFOLFIRINOX or Arm 2 which includes upfront surgery followed by 12 cycles of adjuvant mFOLFIRINOX. The primary endpoint of the trial is overall survival with secondary endpoints evaluating disease-free survival, margin-negative resection rate, surgical complications, and chemotherapeutic adverse events. Additional correlative endpoints include quality of life and radiomic imaging assessments. A total enrollment of 352 patients is planned from the US and Canada; current enrollment for this trial is at 145 patients. An OS interim analysis will be performed when 50% of the events (124) are observed combining the two arms. If the trial continues after interim analysis, the final OS analysis will be performed with a total of 248 events (combined arms). If the Cox model (stratified by tumor location and ECOG PS) comparing OS between arms produces a one-sided p-value < 0.05, then we will conclude that the OS of the perioperative therapy arm is superior to adjuvant therapy. The Alliance A021806 phase III trial aims to define a new standard of care for patients with resectable pancreatic cancer. Clinical trial information: NCT04340141 .
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e22527
Background: BCR-ABL tyrosine kinase inhibitors (TKIs) have revolutionized treatment of Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ALL) and chronic myeloid ...leukemia (CML). The off-target effects of long-term TKI use in children are poorly understood. We evaluated institutional screening practices for cardiac and endocrine late effects in those who had received TKIs at two large pediatric cancer centers. Methods: This retrospective cohort included patients diagnosed with Ph+ALL (post completion of frontline therapy) or CML at age < 21 years with ≥1 years of follow-up. Patients were censored at stem cell transplant, blast crisis, secondary neoplasm, death, or last contact. Demographics, clinical features, and incidence of screening echocardiogram (ECHO), electrocardiogram (EKG), dual-energy x-ray absorptiometry (DXA), bone age, and thyroid function (TSH) were abstracted. Descriptive statistics and incidence of screening are presented by diagnosis. Results: The cohort (n = 68) was 50% female, 28% non-Hispanic white, 24% non-Hispanic black, 24% Asian, and 19% Hispanic. CML: Patients were diagnosed at 12.9±4.6 years of age and had 6.3 (0.9-15.6) years of TKI exposure and 6.3 (0.9-15.6) years of follow-up. Imatinib was most commonly used (80%) followed by dasatinib (59%); 48% were exposed to > 1 TKI. Excluding tests at diagnosis, 48% had an ECHO and 48% had an EKG during the follow-up period. TSH, DXA and bone age were measured in 50%, 9% and 11% patients, respectively. Ph+ALL: Patients were diagnosed at 10.8±5.1 years of age and had 2.8 (0.6-11.6) years of TKI exposure and 5.7 (2.1-11.8) years of follow-up. Dasatinib was most commonly used (73%) followed by imatinib (64%); 36% were exposed to > 1 TKI. All received anthracyclines and steroids. Excluding tests at diagnosis, 91% had an ECHO and 77% had an EKG. TSH, DXA and bone age were measured in 82%, 68% and 36% patients, respectively. Conclusions: We note inconsistent cardiac and endocrine screening in patients receiving TKIs for CML and Ph+ALL. Evidence-based guidelines for long-term follow-up and structured monitoring for potential off-target effects are needed. A prospective screening study is in progress and may enhance our understanding of the prevalence of late effects of TKIs. Table: see text
We consider the notions of static and dynamic reasonableness of requests by an authority in a trust game experiment. The authority, modeled as the experimenter, systematically varies the experimental ...norm of what is expected from trustees to return to trustors, both in terms of the level of each request and in terms of the sequence of the requests. Static reasonableness matters in a self-biased way, in the sense that low requests justify returning less, but high requests tend to be ignored. Dynamic reasonableness also matters, in the sense that, if requests keep increasing, trustees return less compared to the same requests presented in random or decreasing order. Requests never systematically increase trustworthiness but may decrease it.
Objectives
There are no national dementia epidemiological studies using New Zealand (NZ) data. NZ routinely collects health‐care data within the Integrated Data Infrastructure (IDI). The study ...objectives were to 1) investigate late‐onset dementia estimates using the IDI between 2012‐2015 and compare these with 2) published estimates, and 3) variations between North and South Islands and ethnicity.
Methods
A population‐based, retrospective cohort design was applied to routinely collected de‐identified health/administrative IDI data. Dementia was defined by ICD‐10‐AM dementia codes or anti‐dementia drugs.
Results
Approximately 2% of those aged ≥60 years had dementia, lower than published estimates. Dementia was higher in North Island; in 80‐ to 89‐year‐olds; among the Māori population when age‐standardised, and 9% of all dementia cases had >1 dementia sub‐type.
Conclusions
To our knowledge, this is the first study ascertaining dementia estimates using NZ’s whole‐of‐population IDI data. Estimates were lower than existing NZ estimates, for several reasons. Further work is required, including expanding IDI data sets, to develop future estimates that better reflect NZ’s diverse population.
Head and Neck Squamous Cell Carcinoma (HNSCC) is a highly heterogeneous cancer that is characterized by distinct phenotypes based on anatomical site and etiological agents. Recently, the intratumor ...microbiome has been implicated in cancer pathogenesis and progression. Although it is well established that the gut microbiome varies with geographical location and is highly influenced by factors such as diet, environment, and genetics, the intratumor microbiome is not very well characterized. In this review, we aim to characterize the HNSCC intratumor microbiome by geographical location and anatomical site. We conducted a review of primary literature from PubMed and assessed studies based on relevancy and recency. To the best of our knowledge, we are the first to comprehensively examine the tumor microenvironment of HNSCC with respect to these two primary factors on a large scale. Our results suggest that there are unique bacterial and fungal biomarkers for HNSCC for each of the following geographical locations: North America, Asia, Europe, Australia, and Africa. We also identified a panel of microbial biomarkers that are unique to two primary HNSCC anatomic sites, as well as microbial biomarkers associated with various etiological agents of HNSCC. Future study of these microbes may improve HNSCC diagnostic and therapeutic modalities by accounting for differences based on geographic regions and anatomical sites.
Liquid crystalline hydrogels are an attractive class of soft materials to direct charge transport, mechanical actuation, and cell migration. When such systems contain supramolecular polymers, it is ...possible in principle to easily shear align nanoscale structures and create bulk anisotropic properties. However, reproducibly fabricating and patterning aligned supramolecular domains in 3D hydrogels remains a challenge using conventional fabrication techniques. Here, a method is reported for 3D printing of ionically crosslinked liquid crystalline hydrogels from aqueous supramolecular polymer inks. Using a combination of experimental techniques and molecular dynamics simulations, it is found that pH and salt concentration govern intermolecular interactions among the self-assembled structures where lower charge densities on the supramolecular polymers and higher charge screening from the electrolyte result in higher viscosity inks. Enhanced hierarchical interactions among assemblies in high viscosity inks increase the printability and ultimately lead to greater nanoscale alignment in extruded macroscopic filaments when using small nozzle diameters and fast print speeds. Furthermore, the use of this approach is demonstrated to create materials with anisotropic ionic and electronic charge transport as well as scaffolds that trigger the macroscopic alignment of cells due to the synergy of supramolecular self-assembly and additive manufacturing.
In the lower troposphere, rapid collisions between ions
and trace gases result in the transfer of positive charge to the highest
proton affinity species and negative charge to the lowest proton ...affinity
species. Measurements of the chemical composition of ambient ions thus
provide direct insight into the most acidic and basic trace gases and their
ion–molecule clusters – compounds thought to be important for new particle
formation and growth. We deployed an atmospheric pressure interface
time-of-flight mass spectrometer (APi-ToF) to measure ambient ion chemical
composition during the 2016 Holistic Interactions of Shallow Clouds,
Aerosols, and Land Ecosystems (HI-SCALE) campaign at the United States
Department of Energy Atmospheric Radiation Measurement facility in the
Southern Great Plains (SGP), an agricultural region. Cations and anions were
measured for alternating periods of ∼ 24 h over 1 month.
We use binned positive matrix factorization (binPMF) and generalized Kendrick
analysis (GKA) to obtain information about the chemical
formulas and temporal variation in ionic composition without the need for
averaging over a long timescale or a priori high-resolution peak fitting.
Negative ions consist of strong acids including sulfuric and nitric acid,
organosulfates, and clusters of NO3- with highly oxygenated organic
molecules (HOMs) derived from monoterpene (MT) and sesquiterpene (SQT) oxidation.
Organonitrates derived from SQTs account for most of the HOM
signal. Combined with the diel profiles and back trajectory analysis, these
results suggest that NO3 radical chemistry is active at this site.
SQT oxidation products likely contribute to particle growth at the
SGP site. The positive ions consist of bases including alkyl pyridines and
amines and a series of high-mass species. Nearly all the positive ions
contained only one nitrogen atom and in general support ammonia and amines
as being the dominant bases that could participate in new particle
formation. Overall, this work demonstrates how APi-ToF measurements combined
with binPMF analysis can provide insight into the temporal evolution of
compounds important for new particle formation and growth.
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