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2.
JAMA Dermatol ; 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-39046711

RESUMO

Importance: Cutaneous squamous cell carcinoma (CSCC) is the second most common malignant disease in the US. Although it typically carries a good prognosis, a subset of CSCCs are highly aggressive, carrying regional and distant metastatic potential. Due to its high incidence, this aggressive subset is responsible for considerable mortality, with an overall annual mortality estimated to equal or even surpass melanoma. Despite this morbidity, CSCC is excluded from national cancer registries, making it difficult to study its epidemiology and outcomes. Therefore, the bulk of the CSCC literature is composed of single-center and multi-institutional retrospective cohort analyses. Given variations in reporting measures and analyses in these studies, interpretability between studies and the ability to pool results are limited. Objective: To define standardized reporting measures for retrospective CSCC studies. Findings: An expert panel was convened to determine standardized guidelines for recording and analyzing retrospective CSCC data. A total of 13 dermatologists and dermatologic surgeons with more than 5 years of posttraining experience and considerable experience with performing CSCC outcomes research were recruited to the panel. Consensus recommendations were achieved for CSCC retrospective study reporting measures, definitions, and analyses. Conclusions and Relevance: The recommendations in this report present the potential to standardize future CSCC retrospective studies. With such standardization, future work may have greater interstudy interpretability and allow for pooled analyses.

3.
Travel Med Infect Dis ; : 102730, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38830442

RESUMO

BACKGROUND: Travel-related strategies to reduce the spread of COVID-19 evolved rapidly in response to changes in the understanding of SARS-CoV-2 and newly available tools for prevention, diagnosis, and treatment. Modeling is an important methodology to investigate the range of outcomes that could occur from different disease containment strategies. METHODS: We examined 43 articles published from December 2019 through September 2022 that used modeling to evaluate travel-related COVID-19 containment strategies. We extracted and synthesized data regarding study objectives, methods, outcomes, populations, settings, strategies, and costs. We used a standardized approach to evaluate each analysis according to 26 criteria for modeling quality and rigor. RESULTS: The most frequent approaches included compartmental modeling to examine quarantine, isolation, or testing. Early in the pandemic, the goal was to prevent travel-related COVID-19 cases with a focus on individual-level outcomes and assessing strategies such as travel restrictions, quarantine without testing, social distancing, and on-arrival PCR testing. After the development of diagnostic tests and vaccines, modeling studies projected population-level outcomes and investigated these tools to limit COVID-19 spread. Very few published studies included rapid antigen screening strategies, costs, explicit model calibration, or critical evaluation of the modeling approaches. CONCLUSION: Future modeling analyses should leverage open-source data, improve the transparency of modeling methods, incorporate newly available prevention, diagnostics, and treatments, and include costs and cost-effectiveness so that modeling analyses can be informative to address future SARS-CoV-2 variants of concern and other emerging infectious diseases (e.g., mpox and Ebola) for travel-related health policies.

4.
J Vis Exp ; (207)2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38856221

RESUMO

The adaptive immune response is reliant on a T cell's ability to migrate through blood, lymph, and tissue in response to pathogens and foreign bodies. T cell migration is a complex process that requires the coordination of many signal inputs from the environment and local immune cells, including chemokines, chemokine receptors, and adhesion molecules. Furthermore, T cell motility is influenced by dynamic surrounding environmental cues, which can alter activation state, transcriptional landscape, adhesion molecule expression, and more. In vivo, the complexity of these seemingly intertwined factors makes it difficult to distinguish individual signals that contribute to T cell migration. This protocol provides a string of methods from T cell isolation to computer-aided analysis to assess T cell migration in real-time under highly specific environmental conditions. These conditions may help elucidate mechanisms that regulate migration, improving our understanding of T cell kinetics and providing strong mechanistic evidence that is difficult to attain through animal experiments. A deeper understanding of the molecular interactions that impact cell migration is important to develop improved therapeutics.


Assuntos
Linfócitos T CD8-Positivos , Movimento Celular , Animais , Camundongos , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/citologia , Movimento Celular/fisiologia , Movimento Celular/imunologia , Ensaios de Migração Celular/métodos
5.
medRxiv ; 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38853958

RESUMO

Sleep-wake disturbances frequently present in Veterans with mild traumatic brain injury (mTBI). These TBI-related sleep impairments confer significant burden and commonly exacerbate other functional impairments. Therapies to improve sleep following mTBI are limited and studies in Veterans are even more scarce. In our previous pilot work, morning bright light therapy (MBLT) was found to be a feasible behavioral sleep intervention in Veterans with a history of mTBI; however, this was single-arm, open-label, and non-randomized, and therefore was not intended to establish efficacy. The present study, LION (light vs ion therapy) extends this preliminary work as a fully powered, sham-controlled, participant-masked randomized controlled trial (NCT03968874), implemented as fully remote within the VA (target n=120 complete). Randomization at 2:1 allocation ratio to: 1) active: MBLT (n=80), and 2) sham: deactivated negative ion generator (n=40); each with identical engagement parameters (60-min duration; within 2-hrs of waking; daily over 28-day duration). Participant masking via deception balanced expectancy assumptions across arms. Outcome measures were assessed following a 14-day baseline (pre-intervention), following 28-days of device engagement (post-intervention), and 28-days after the post-intervention assessment (follow-up). Primary outcomes were sleep measures, including continuous wrist-based actigraphy, self-report, and daily sleep dairy entries. Secondary/exploratory outcomes included cognition, mood, quality of life, circadian rhythm via dim light melatonin onset, and biofluid-based biomarkers. Participant drop out occurred in <10% of those enrolled, incomplete/missing data was present in <15% of key outcome variables, and overall fidelity adherence to the intervention was >85%, collectively establishing feasibility and acceptability for MBLT in Veterans with mTBI.

6.
Heart Rhythm ; 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38936445

RESUMO

BACKGROUND: Traditional post-approval study (PAS) designs have been accepted by regulatory authorities to fulfill postmarketing requirements for cardiac leads, but they have several limitations. OBJECTIVE: We conducted a proof-of-concept study of alternative methods that use real-world data (RWD) to evaluate lead safety in large populations of patients. METHODS: Abbott patient device databases were linked with Medicare Fee-For-Service (FFS) claims to identify lead complications in patients implanted with Abbott Optisure lead. A 1:1 comparison between the PAS method and RWD method of detecting mechanical lead-related complication events was conducted in 444 PAS participants who were enrolled in Medicare FFS. Agreement between methods was evaluated by McNemar test and Cohen κ. Survival free from complications at 3 years was compared between the PAS and RWD cohorts with an equivalence acceptance criterion of ±2.5%. RESULTS: There were 1171 PAS patients and 5804 Medicare FFS patients who received an Optisure lead between August 27, 2014, and June 14, 2016. Patients were observed through December 31, 2018. Complete agreement was found between PAS-reported and claims-detected complications (McNemar P value = 1; Cohen κ = 1). Survival free from complications at 3 years by the RWD method was 98.4% (95% confidence limit, 98.0%-98.7%), which was within the acceptable range of the PAS 98.4% (95% confidence limit, 97.6%-99.0%). CONCLUSION: These results show a close agreement between RWD-detected and PAS-reported lead complication rates, which highlights the potential benefits of RWD-based methods to enhance the generation of clinical evidence for lead safety.

7.
Health Aff (Millwood) ; 43(6): 831-839, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38830157

RESUMO

Over the course of the past two decades, attrition within the US governmental public health workforce has passed concerning and become dire. The practice sector has struggled to recruit and retain new talent, despite the infusion of considerable federal investment in workforce expansion initiatives. In 2020, Emory University's Rollins School of Public Health partnered with the Georgia Department of Public Health to establish the Rollins Epidemiology Fellowship Program. Initially created to recruit and place early-career master of public health-level epidemiologists into Georgia's public health system for COVID-19 pandemic response, the two-year service-learning program has evolved into an effective and replicable model of direct academic involvement in strengthening the governmental public health workforce. Here we describe the program's structure and early results, spotlighting it for consideration by the federal government and other jurisdictions interested in directly engaging academia in efforts to revitalize the public health workforce.


Assuntos
COVID-19 , Bolsas de Estudo , Humanos , Georgia , COVID-19/epidemiologia , Epidemiologia/educação , Saúde Pública , Mão de Obra em Saúde , Recursos Humanos
8.
J Am Chem Soc ; 146(22): 15420-15427, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38768558

RESUMO

We report the strain-induced [2 + 2] cycloadditions of cyclic allenes for the assembly of highly substituted cyclobutanes. By judicious choice of trapping agent, complex scaffolds bearing heteroatoms, fused rings, contiguous stereocenters, spirocycles, and quaternary centers are ultimately accessible. Moreover, we show that the resulting cycloadducts can undergo thermal isomerization. This study provides an alternative strategy to photochemical [2 + 2] cycloadditions for accessing highly functionalized cyclobutanes, while validating the use of underexplored strained intermediates for the assembly of complex architectures.

9.
New Phytol ; 243(2): 560-566, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38812264

RESUMO

Increasing atmospheric CO2 is changing the dynamics of tropical savanna vegetation. C3 trees and grasses are known to experience CO2 fertilization, whereas responses to CO2 by C4 grasses are more ambiguous. Here, we sample stable carbon isotope trends in herbarium collections of South African C4 and C3 grasses to reconstruct 13C discrimination. We found that C3 grasses showed no trends in 13C discrimination over the past century but that C4 grasses increased their 13C discrimination through time, especially since 1950. These changes were most strongly linked to changes in atmospheric CO2 rather than to trends in rainfall climatology or temperature. Combined with previously published evidence that grass biomass has increased in C4-dominated savannas, these trends suggest that increasing water-use efficiency due to CO2 fertilization may be changing C4 plant-water relations. CO2 fertilization of C4 grasses may thus be a neglected pathway for anthropogenic global change in tropical savanna ecosystems.


Assuntos
Dióxido de Carbono , Isótopos de Carbono , Poaceae , Dióxido de Carbono/metabolismo , Poaceae/metabolismo , Isótopos de Carbono/análise , Chuva
10.
Cells ; 13(10)2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38786066

RESUMO

Immune cell migration is required for the development of an effective and robust immune response. This elegant process is regulated by both cellular and environmental factors, with variables such as immune cell state, anatomical location, and disease state that govern differences in migration patterns. In all cases, a major factor is the expression of cell surface receptors and their cognate ligands. Rapid adaptation to environmental conditions partly depends on intrinsic cellular immune factors that affect a cell's ability to adjust to new environment. In this review, we discuss both myeloid and lymphoid cells and outline key determinants that govern immune cell migration, including molecules required for immune cell adhesion, modes of migration, chemotaxis, and specific chemokine signaling. Furthermore, we summarize tumor-specific elements that contribute to immune cell trafficking to cancer, while also exploring microenvironment factors that can alter these cellular dynamics within the tumor in both a pro and antitumor fashion. Specifically, we highlight the importance of the secretome in these later aspects. This review considers a myriad of factors that impact immune cell trajectory in cancer. We aim to highlight the immunotherapeutic targets that can be harnessed to achieve controlled immune trafficking to and within tumors.


Assuntos
Movimento Celular , Neoplasias , Microambiente Tumoral , Humanos , Neoplasias/imunologia , Neoplasias/patologia , Microambiente Tumoral/imunologia , Animais , Linfócitos/imunologia , Linfócitos/metabolismo , Transdução de Sinais
11.
JCI Insight ; 9(9)2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38716730

RESUMO

Lung cancer is the leading cause of cancer-related deaths in the world, and non-small cell lung cancer (NSCLC) is the most common subset. We previously found that infiltration of tumor inflammatory monocytes (TIMs) into lung squamous carcinoma (LUSC) tumors is associated with increased metastases and poor survival. To further understand how TIMs promote metastases, we compared RNA-Seq profiles of TIMs from several LUSC metastatic models with inflammatory monocytes (IMs) of non-tumor-bearing controls. We identified Spon1 as upregulated in TIMs and found that Spon1 expression in LUSC tumors corresponded with poor survival and enrichment of collagen extracellular matrix signatures. We observed SPON1+ TIMs mediate their effects directly through LRP8 on NSCLC cells, which resulted in TGF-ß1 activation and robust production of fibrillar collagens. Using several orthogonal approaches, we demonstrated that SPON1+ TIMs were sufficient to promote NSCLC metastases. Additionally, we found that Spon1 loss in the host, or Lrp8 loss in cancer cells, resulted in a significant decrease of both high-density collagen matrices and metastases. Finally, we confirmed the relevance of the SPON1/LRP8/TGF-ß1 axis with collagen production and survival in patients with NSCLC. Taken together, our study describes how SPON1+ TIMs promote collagen remodeling and NSCLC metastases through an LRP8/TGF-ß1 signaling axis.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Monócitos , Transdução de Sinais , Animais , Humanos , Camundongos , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/secundário , Linhagem Celular Tumoral , Colágeno/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Proteínas da Matriz Extracelular/genética , Proteínas Relacionadas a Receptor de LDL/metabolismo , Proteínas Relacionadas a Receptor de LDL/genética , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Neoplasias Pulmonares/genética , Monócitos/metabolismo , Monócitos/patologia , Metástase Neoplásica , Fator de Crescimento Transformador beta1/metabolismo
12.
Dermatol Surg ; 50(6): 558-564, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38578837

RESUMO

BACKGROUND: Mohs micrographic surgery efficiently treats skin cancer through staged resection, but surgeons' varying resection rates may lead to higher medical costs. OBJECTIVE: To evaluate the cost savings associated with a quality improvement. MATERIALS AND METHODS: The authors conducted a retrospective cohort study using 100% Medicare fee-for-service claims data to identify the change of mean stages per case for head/neck (HN) and trunk/extremity (TE) lesions before and after the quality improvement intervention from 2016 to 2021. They evaluated surgeon-level change in mean stages per case between the intervention and control groups, as well as the cost savings to Medicare over the same time period. RESULTS: A total of 2,014 surgeons performed Mohs procedures on HN lesions. Among outlier surgeons who were notified, 31 surgeons (94%) for HN and 24 surgeons (89%) for TE reduced their mean stages per case with a median reduction of 0.16 and 0.21 stages, respectively. Reductions were also observed among outlier surgeons who were not notified, reducing their mean stages per case by 0.1 and 0.15 stages, respectively. The associated total 5-year savings after the intervention was 92 million USD. CONCLUSION: The implementation of this physician-led benchmarking model was associated with broad reductions of physician utilization and significant cost savings.


Assuntos
Redução de Custos , Medicare , Cirurgia de Mohs , Melhoria de Qualidade , Neoplasias Cutâneas , Humanos , Estudos Retrospectivos , Medicare/economia , Estados Unidos , Melhoria de Qualidade/economia , Redução de Custos/estatística & dados numéricos , Neoplasias Cutâneas/cirurgia , Neoplasias Cutâneas/economia , Cirurgia de Mohs/economia , Seguimentos , Padrões de Prática Médica/economia , Padrões de Prática Médica/estatística & dados numéricos , Masculino , Feminino , Cirurgiões/economia , Cirurgiões/estatística & dados numéricos , Neoplasias de Cabeça e Pescoço/cirurgia , Neoplasias de Cabeça e Pescoço/economia
13.
J Clin Invest ; 134(11)2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38652563

RESUMO

While dysfunction and death of light-detecting photoreceptor cells underlie most inherited retinal dystrophies, knowledge of the species-specific details of human rod and cone photoreceptor cell development remains limited. Here, we generated retinal organoids carrying retinal disease-causing variants in NR2E3, as well as isogenic and unrelated controls. Organoids were sampled using single-cell RNA sequencing (scRNA-Seq) across the developmental window encompassing photoreceptor specification, emergence, and maturation. Using scRNA-Seq data, we reconstruct the rod photoreceptor developmental lineage and identify a branch point unique to the disease state. We show that the rod-specific transcription factor NR2E3 is required for the proper expression of genes involved in phototransduction, including rhodopsin, which is absent in divergent rods. NR2E3-null rods additionally misexpress several cone-specific phototransduction genes. Using joint multimodal single-cell sequencing, we further identify putative regulatory sites where rod-specific factors act to steer photoreceptor cell development. Finally, we show that rod-committed photoreceptor cells form and persist throughout life in a patient with NR2E3-associated disease. Importantly, these findings are strikingly different from those observed in Nr2e3 rodent models. Together, these data provide a road map of human photoreceptor development and leverage patient induced pluripotent stem cells to define the specific roles of rod transcription factors in photoreceptor cell emergence and maturation in health and disease.


Assuntos
Organoides , Receptores Nucleares Órfãos , Células Fotorreceptoras Retinianas Bastonetes , Humanos , Organoides/metabolismo , Organoides/patologia , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Células Fotorreceptoras Retinianas Bastonetes/patologia , Receptores Nucleares Órfãos/genética , Receptores Nucleares Órfãos/metabolismo , Células Fotorreceptoras Retinianas Cones/metabolismo , Células Fotorreceptoras Retinianas Cones/patologia , Retina/metabolismo , Retina/patologia , Retina/crescimento & desenvolvimento , Diferenciação Celular , Transdução de Sinal Luminoso/genética , Análise de Célula Única
14.
PeerJ ; 12: e17211, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38623495

RESUMO

Background: Prior research suggests that trematode rediae, a developmental stage of trematode parasites that reproduce clonally within a snail host, show evidence of division of labor (DOL). Single-species infections often have two morphologically distinct groups: small rediae, the 'soldiers', are active, aggressive, and do not appear to reproduce; large rediae, the 'reproductives', are larger, sluggish, and full of offspring. Most data supporting DOL come from trematodes infecting marine snails, while data from freshwater trematodes are more limited and generally do not supported DOL. The shorter lifespan typical of freshwater snails may partially explain this difference: defending a short-lived host at the expense of reproduction likely provides few advantages. Here, we present data from sixty-one colonies spanning twenty species of freshwater trematode exploring morphological and behavioral patterns commonly reported from marine trematodes believed to have DOL. Methods: Trematode rediae were obtained from sixty-one infected snails collected in central Vermont, USA. A portion of the COI gene was sequenced to make tentative species identifications ('COI species'). Samples of rediae were photographed, observed, and measured to look for DOL-associated patterns including a bimodal size distribution, absence of embryos in small rediae, and pronounced appendages and enlarged pharynges (mouthparts) in small rediae. Additional rediae were used to compare activity levels and likelihood to attack heterospecific trematodes in large vs. small rediae. Results: Many of the tests for DOL-associated patterns showed mixed results, even among colonies of the same COI species. However, we note a few consistent patterns. First, small rediae of most colonies appeared capable of reproduction, and we saw no indication (admittedly based on a small sample size and possibly insufficient attack trial methodology) that small rediae were more active or aggressive. This differs from patterns reported from most marine trematodes. Second, the small rediae of most colonies had larger pharynges relative to their body size than large rediae, consistent with marine trematodes. We also observed that colonies of three sampled COI species appear to produce a group of large rediae that have distinctly large pharynges. Conclusions: We conclude that these freshwater species likely do not have a group of specialized non-reproductive soldiers because small rediae of at least some colonies in almost every species do appear to produce embryos. We cannot rule out the possibility that small rediae act as a temporary soldier caste. We are intrigued by the presence of rediae with enlarged pharynges in some species and propose that they may serve an adaptive role, possibly similar to the defensive role of small 'soldier' rediae of marine trematodes. Large-pharynx rediae have been documented in other species previously, and we encourage future efforts to study these large-pharynx rediae.


Assuntos
Trematódeos , Animais , Trematódeos/genética , Caramujos/genética , Comportamento Animal , Comportamento Social , Agressão
15.
JACC Heart Fail ; 12(7): 1212-1222, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38530702

RESUMO

BACKGROUND: Inadequate inclusion in clinical trial enrollment may contribute to health inequities by evaluating interventions in cohorts that do not fully represent target populations. OBJECTIVES: The aim of this study was to determine if characteristics of patients with heart failure (HF) enrolled in a pivotal trial are associated with who receives an intervention after approval. METHODS: Demographics from 2,017,107 Medicare patients hospitalized for HF were compared with those of the first 10,631 Medicare beneficiaries who received implantable pulmonary artery pressure sensors. Characteristics of the population studied in the pivotal CHAMPION (CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients) clinical trial (n = 550) were compared with those of both groups. All demographic data were analyzed nationally and in 4 U.S. regions. RESULTS: The Medicare HF cohort included 80.9% White, 13.3% African American, 1.9% Hispanic, 1.3% Asian, and 51.5% female patients. Medicare patients <65 years of age were more likely to be African American (33%) and male (58%), whereas older patients were mostly White (84%) and female (53%). Forty-one percent of U.S. HF hospitalizations occurred in the South; demographic characteristics varied significantly across all U.S. regions. The CHAMPION trial adequately represented African Americans (23% overall, 35% <65 years of age), Hispanic Americans (2%), and Asian Americans (1%) but underrepresented women (27%). The trial's population characteristics were similar to those of the first patients who received pulmonary artery sensors (82% White, 13% African American, 1% Asian, 1% Hispanic, and 29% female). CONCLUSIONS: Demographics of Centers for Medicare and Medicaid Services beneficiaries hospitalized with HF vary regionally and by age, which should be considered when defining "adequate" representation in clinical studies. Enrollment diversity in clinical trials may affect who receives early application of recently approved innovations.


Assuntos
Ensaios Clínicos como Assunto , Insuficiência Cardíaca , Medicare , Humanos , Masculino , Feminino , Insuficiência Cardíaca/terapia , Idoso , Estados Unidos , Pessoa de Meia-Idade , Seleção de Pacientes , Idoso de 80 Anos ou mais , Hospitalização/estatística & dados numéricos
16.
bioRxiv ; 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38496491

RESUMO

The neural mechanisms that willfully direct attention to specific locations in space are closely related to those for generating targeting eye movements (saccades). However, the degree to which the voluntary deployment of attention to a location is necessarily accompanied by a corresponding saccade plan remains unclear. One problem is that attention and saccades are both automatically driven by salient sensory events; another is that the underlying processes unfold within tens of milliseconds only. Here, we use an urgent task design to resolve the evolution of a visuomotor choice on a moment-by-moment basis while independently controlling the endogenous (goal-driven) and exogenous (salience-driven) contributions to performance. Human participants saw a peripheral cue and, depending on its color, either looked at it (prosaccade) or looked at a diametrically opposite, uninformative non-cue (antisaccade). By varying the luminance of the stimuli, the exogenous contributions could be cleanly dissociated from the endogenous process guiding the choice over time. According to the measured timecourses, generating a correct antisaccade requires about 30 ms more processing time than generating a correct prosaccade based on the same perceptual signal. The results indicate that saccade plans are biased toward the location where attention is endogenously deployed, but the coupling is weak and can be willfully overridden very rapidly.

17.
ACS Omega ; 9(9): 10979-10991, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38463331

RESUMO

Voloxidation is a potential alternative reprocessing scheme for spent nuclear fuel that uses gas-solid reactions to minimize aqueous wastes and to separate volatile fission products from the desired actinide phase. The process uses NO2(g) as an oxidant for uranium dioxide (UO2) fuel, ideally producing soluble uranium powders which can then be processed for full recycle. To continue development of the process flowsheet for voloxidation, ongoing examination of the process chemistry and associated process materials is required: discrepancies in the proposed chemical reactions that occur when spent nuclear fuel is exposed to NO2(g) atmospheres must be addressed. The objective of this work is to analyze the intermediate solid phases produced during voloxidation to support verification of the proposed NO2(g) voloxidation reaction mechanisms. This objective was achieved through using (1) powder X-ray diffraction and Raman spectroscopy to identify bulk uranium phases and (2) scanning electron microscopy to describe the morphology and microstructure of the powders at each reaction stage. The initial oxidation of UO2 under NO2(g) reactions produced ε-UO3. Further exposure to NO2(g) did not nitrate the solid to produce uranyl nitrate, as reported in some literature. However, after the powder was hydrated with steam and then further exposed to NO2(g), some traces of uranyl nitrate hexahydrate were found. The results of this study suggest that surface hydration of powders plays a vital role in uranyl nitrate formation under voloxidation conditions and raises questions about the kinetics of the oxide-to-nitrate voloxidation conversion process. Future chemical and engineering design decisions for the voloxidation process may benefit from an improved understanding of these chemical mechanisms.

19.
Proc (Bayl Univ Med Cent) ; 37(2): 205-209, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38343487

RESUMO

Background: Conduction abnormality requiring the implantation of a permanent pacemaker (PPM) is a well-known and clinically important complication of transcatheter aortic valve replacement (TAVR). However, PPM implantation may result in lead-associated tricuspid valve regurgitation (TR). This study sought to determine the incidence and progression of TR following PPM implantation after TAVR. Methods: This was a retrospective review of all echocardiograms of patients who underwent PPM following TAVR at the Baylor Scott & White hospitals from 2012 to 2021. The primary endpoint was TR progression at 30 days and 1 year. A subanalysis comparing the change in TR progression between small and large TAVR devices was also conducted. Secondary outcomes included all-cause death at 30 days and 1 year. Results: Out of the 2744 patients who underwent TAVR between April 2012 and August 2021, 177 patients (6.5%) subsequently received a new PPM. There was a statistically significant progression of TR at 1-year follow-up (McNemar's P value = 0.02). TR progression rates were comparable between the small and large valve groups at 1-year follow-up (4% vs 11%, P = 0.09, respectively). Conclusion: In this single healthcare system study, we demonstrated a significant progression of TR in patients with PPM post TAVR at 1 year.

20.
Cureus ; 16(1): e52315, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38357061

RESUMO

Recurrent episodes of subglottic stenosis are rare in the literature, and the etiologic causes are misunderstood but can be congenital, idiopathic, or iatrogenic in nature. Complications of intubation can result in subsequent inflammation and reactive processes. This case involves a 16-month-old male who suffered from a recurrent episode of subglottic stenosis in the setting of croup, influenza, and honey consumption. He had presented to the emergency department in respiratory distress after ingesting a home remedy of onion juice and honey. He had been discharged one day prior from the pediatric intensive care unit after four days of intubation and a seven-day hospital course with evidence of croup on imaging. He was readmitted, and subglottic edema and narrowing were confirmed via endoscopy, which prompted antibiotic treatment and close monitoring. After three days of monitoring and re-evaluation by bronchoscopy, the patient's condition began to improve, and no intubation was necessary. It is unclear what the cause of recurrent subglottic stenosis is due to the patient's clinical picture being clouded by a potential allergic reaction to honey versus an inflammatory reactive process post-intubation from the previous admission days prior. This case emphasizes the need for further research on the prevalence and etiology of recurrent subglottic stenosis and a deeper understanding of how to optimize diagnosis and treatment.

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