Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 99
Filtrar
1.
Chem Mater ; 36(9): 4481-4494, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38764752

RESUMO

Four different high-entropy spinel oxide ferrite (HESO) electrode materials containing 5-6 distinct metals were synthesized by a simple, rapid combustion synthesis process and evaluated as conversion anode materials in lithium half-cells. All showed markedly superior electrochemical performance compared to conventional spinel ferrites such as Fe3O4 and MgFe2O4, having capacities that could be maintained above 600 mAh g-1 for 150 cycles, in most cases. X-ray absorption spectroscopy (XAS) results on pristine, discharged, and charged electrodes show that Fe, Co, Ni, and Cu are reduced to the elemental state during the first discharge (lithiation), while Mn is only slightly reduced. Upon recharge (delithiation), Fe is reoxidized to an average oxidation state of about 2.6+, while Co, Ni, and Cu are not reoxidized. The ability of Fe to be oxidized past 2+ accounts for the high capacities observed in these materials, while the presence of metallic elements after the initial lithiation provides an electronically conductive network that aids in charge transfer.

2.
Eur Eat Disord Rev ; 32(2): 230-243, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37837332

RESUMO

This study examined the feasibility and preliminary effectiveness of a cognitive-behavioral, family-centered partial hospitalization program (PHP) for adolescents with anorexia nervosa (AN) and atypical AN (AAN), and described the outpatient services received following discharge. Participants (N = 31) completed anthropometric and self-report assessments at admission, discharge, and six and twelve months after discharge from the PHP. Descriptive statistics explored markers of feasibility. Paired samples t-tests evaluated changes in weight and eating disorder (ED) symptomatology from admission to discharge, admission to six-month follow-up, and admission to twelve-month follow-up. Descriptive statistics and effect sizes compared symptoms at each timepoint between participants with AN and AAN. Results indicated that we were successful at recruiting greater than 50% of adolescents approached for this study. We collected follow-up data from more than 70% of participants at discharge, but did not meet this retention benchmark at six-month and twelve-month follow-ups. The entire sample demonstrated significant improvements in weight and ED symptomatology from admission to discharge, and generally maintained these improvements at six- and twelve-month follow-up. While descriptive statistics suggested that participants with AN and AAN received similar outpatient services following discharge from the PHP, those with AN experienced greater improvement in self-reported ED symptomatology than those with AAN at six- and twelve-month follow-up. These findings provide preliminary support for the efficacy of PHPs in treating adolescents with AN and AAN. Further research with larger sample sizes should investigate whether adolescents with AAN experience poorer outcomes than those with AN following discharge from a PHP.


Assuntos
Anorexia Nervosa , Humanos , Adolescente , Anorexia Nervosa/terapia , Seguimentos , Hospital Dia , Estudos de Viabilidade , Cognição
3.
West J Emerg Med ; 24(3): 390-395, 2023 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-37278783

RESUMO

INTRODUCTION: The number of emergency department observation units (EDOU) and observation stays has continued to increase. Despite this, there is limited data on the characteristics of patients who return unexpectedly to the ED after EDOU discharge. METHODS: We identified the charts of all patients who were admitted to the EDOU of an academic medical center between January 2018-June 2020 and had a return to the ED within 14 days of discharge from the EDOU. Patients were excluded if they were admitted to the hospital from the EDOU, left against medical advice, or died in the EDOU. We manually extracted selected demographic factors, comorbidities, and healthcare utilization data from the charts. Physician reviewers identified return visits thought to be related to the index visit or potentially avoidable. RESULTS: During the study period, there were 176,471 ED visits, 4,179 admissions to the EDOU, and 333 return visits to the ED within 14 days from discharge from the EDOU, representing 9.4% of all patients discharged from the EDOU. We identified a higher rate of return for patients treated for asthma and lower rates of return for patients treated for chest pain or syncope than the overall return rate. Physician reviewers determined that 64.6% of unplanned returns were related to the index visit, and 4.5% were potentially avoidable. Of potentially avoidable visits, 53.3% occurred within 48 hours of discharge, supporting the use of this period as a potential quality metric. While there was no significant difference in the percentage of related return visits between males and females, there was a higher rate of potentially avoidable visits for male patients. CONCLUSION: This study adds to the limited body of literature on EDOU returns, finding an overall return rate of under 10%, with about two-thirds of returns determined to be related to the index visit and <5% considered to be potentially avoidable.


Assuntos
Unidades de Observação Clínica , Alta do Paciente , Feminino , Humanos , Masculino , Tempo de Internação , Hospitalização , Serviço Hospitalar de Emergência , Estudos Retrospectivos
4.
ACS Appl Mater Interfaces ; 15(20): 24306-24318, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37163664

RESUMO

Two-dimensional (2D) siloxene (Si6O3H6) has shown promise as a negative electrode material for Li-ion batteries due to its high gravimetric capacity and superior mechanical properties under (de)lithiation compared to bulk Si. In this work, we prepare purified siloxene nanosheets through the removal of bulk Si contaminants, use ultrasonication to control the lateral size and thickness of the nanosheets, and probe the effects of the resulting morphology and purity on the electrochemistry. The thin siloxene nanosheets formed after 4 h of ultrasonication deliver an average capacity of 810 mA h/g under a 1000 mA/g rate over 200 cycles with a capacity retention of 76%. Interestingly, the purified siloxene shows lower initial capacity but superior capacity retention over extended cycling. The 2D morphology benefit is illustrated where the parent siloxene nanosheet morphology and structure were largely maintained based on operando optoelectrochemistry, in situ Raman, ex situ scanning electron microscopy, and ex situ transmission electron microscopy. Furthermore, the purified siloxene-based electrode free from crystalline Si impurity experiences the least expansion upon (de)lithiation as visualized by cross-section electron microscopy of samples recovered post-cycling.

5.
J Cancer Educ ; 38(5): 1636-1640, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37225924

RESUMO

Cancer Care Experience (CCE) is a unique elective educational program to further explore the subspecialty of oncology beyond the scope of the traditional undergraduate medical education curriculum. During the COVID-19 pandemic, CCE moved from an in-person to a virtual learning platform. This transition allowed program leaders to offer CCE as a multi-institutional program, with students participating from both Duke University School of Medicine and Penn State College of Medicine. Our study aimed to investigate the effectiveness of virtual learning, student perspectives on multi-institutional collaboration, and the program's impact on the student's understanding of oncology care and clerkship preparedness. Overall, students indicated CCE was an impactful program for them to learn more about oncology and that virtual learning was an effective learning platform. Furthermore, our results suggest students found the multi-institutional aspect valuable and that a multi-institution, hybrid (in-person and virtual) platform was preferred. Our study highlights the success of CCE as a multi-institution program and an effective elective program to expose students to the field of oncology further.


Assuntos
COVID-19 , Educação de Graduação em Medicina , Estudantes de Medicina , Humanos , COVID-19/epidemiologia , Pandemias , Currículo , Estudantes
6.
Cureus ; 15(2): e35535, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37007306

RESUMO

INTRODUCTION: The Objective Structured Clinical Examination (OSCE) is utilized by medical schools to assess students' competency in clinical skills. Literature has shown that first-year students who were tutored by fourth-year students (MS4s; near-peer) in practice OSCEs reported self-perceived improvement in OSCE skills. There is a lack of research regarding the effectiveness of first-year (MS1) pairs for reciprocal-peer practice OSCEs. This study aims to assess if virtual reciprocal-peer OSCEs provide comparable learning opportunities to virtual near-peer OSCEs. METHODS: MS1 students were assigned to work with a near-peer or a reciprocal-peer for one week, and then switched protocols the second week. One student in each reciprocal-peer pair was assigned to act as a standardized patient (SP). Their partner took a history, interpreted physical exam findings, prepared a note, and gave an oral presentation. The pair then switched roles using a second case. The near-peer group followed the same procedure, without the reversal of roles. RESULTS: A total of 135 MS1s participated in the first week and 129 in the second week. Students agreed that working with a near-peer was more valuable than a reciprocal-peer in the following parameters: peer feedback (N=113, 89%), history-taking skills (N=101, 80%), physical exam skills (N=102, 81%), and note-writing skills (N=109, 89%). Pairwise comparison utilizing Wilcoxon signed-rank test indicated participants preferred the choice of a fourth-year student partner over an MS1 partner (Z=1.436, p<0.001). CONCLUSION: Participants found working with a near-peer increased confidence in their clinical skills and near-peer feedback was more valuable. Although MS1s found that watching and evaluating their peers in a reciprocal-peer exercise was beneficial, students overwhelmingly preferred working with MS4s due to more valuable feedback.

7.
Am J Cardiol ; 186: 181-185, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36270826

RESUMO

Adverse cardiac events after laparoscopic bariatric surgery are rare, yet preoperative cardiology evaluation and testing remain common, resulting in the overuse of cardiac testing in low-risk patients. Our objective was to assess the frequency of, and factors associated with, overuse of preoperative cardiac testing in patients at low cardiac risk before laparoscopic bariatric surgery. We retrospectively reviewed data from 1,094 adult patients who underwent laparoscopic bariatric surgery at our institution from January 1, 2015, through December 31, 2019. The cardiac risk was determined using the Revised Cardiac Risk Index (RCRI) and the National Surgical Quality Improvement Program Myocardial Infarction and Cardiac Arrest (NSQIP MICA) risk model. Multivariate logistic regression was used to evaluate risk factors associated with the overuse of cardiac testing in low-risk patients. Overall, 1,059 patients (96.8%) were estimated to be at low cardiac risk by the RCRI, and 1,094 (100%) were at low cardiac risk by NSQIP MICA. A total of 587 patients (51.8%) were referred to cardiology for preoperative evaluation, and 643 patients (56.7%) underwent one or more preoperative cardiac tests. Factors associated with overuse of preoperative cardiac testing in low-risk patients included preoperative cardiology referral (adjusted odds ratio 37.2, 95% confidence interval 25.3 to 54.7) and patient age (adjusted odds ratio 1.05, 95% confidence interval 1.03 to 1.07). Overuse of preoperative cardiac testing was common in patients at low cardiac risk before laparoscopic bariatric surgery. Preoperative referral to cardiology was the most significant risk factor associated with the overuse of preoperative cardiac testing. Application of risk models such as the RCRI or NSQIP MICA at the time of bariatric program enrollment may reduce unnecessary preoperative cardiac testing in low-risk patients.


Assuntos
Cirurgia Bariátrica , Laparoscopia , Adulto , Humanos , Estudos Retrospectivos , Cirurgia Bariátrica/efeitos adversos , Fatores de Risco , Complicações Pós-Operatórias/etiologia , Laparoscopia/efeitos adversos , Laparoscopia/métodos , Medição de Risco/métodos
8.
Ambio ; 52(1): 15-29, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35882751

RESUMO

The COVID-19 pandemic and related social and economic emergencies induced massive public spending and increased global debt. Economic recovery is now an opportunity to rebuild natural capital alongside financial, physical, social and human capital, for long-term societal benefit. Yet, current decision-making is dominated by economic imperatives and information systems that do not consider society's dependence on natural capital and the ecosystem services it provides. New international standards for natural capital accounting (NCA) are now available to integrate environmental information into government decision-making. By revealing the effects of policies that influence natural capital, NCA supports identification, implementation and monitoring of Green Recovery pathways, including where environment and economy are most positively interlinked.


Assuntos
COVID-19 , Ecossistema , Humanos , Conservação dos Recursos Naturais , COVID-19/epidemiologia , Pandemias
9.
Dis Colon Rectum ; 66(2): 262-268, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-35714339

RESUMO

BACKGROUND: Patients with inflammatory bowel disease have an increased risk of colorectal cancer and are recommended to undergo increased surveillance compared to the general population. Currently, inadequate evidence exists to guide management of colonic dysplasia discovered during screening of inflammatory bowel disease patients. OBJECTIVE: The goal of this study was to determine the risk of colorectal cancer in patients with ulcerative colitis or Crohn's disease with dysplasia on colonoscopy. DESIGN: This was a retrospective study. SETTING: This study was conducted at a high-volume, quaternary referral center with an inflammatory bowel disease program. PATIENTS: Patients with a diagnosis of inflammatory bowel disease with colonoscopy within 6 months of colectomy were included. MAIN OUTCOME MEASURES: The primary outcome measures included finding of colorectal cancer at time of colectomy. RESULTS: There were 621 patients, 233 with ulcerative colitis and 388 with Crohn's disease. Of ulcerative colitis patients, 25 had low-grade dysplasia on colonoscopy with 1 (4%) found to have colorectal cancer at colectomy. High-grade dysplasia was noted preoperatively in 14 and colorectal cancer was found in 4 (29%) after colectomy. Compared to no dysplasia, low-grade dysplasia did not increase the risk of colorectal cancer (OR 1.98, p = 0.47), but high-grade dysplasia had an increased risk (OR 19.0, p < 0.001) of colorectal cancer. For the 7 patients with Crohn's disease and low-grade dysplasia, colorectal cancer was found in 1 patient (14%) at colectomy. High-grade dysplasia was noted preoperatively in 4 patients with Crohn's Disease, and colorectal cancer was found in 3 patients (75%) after colectomy. Compared to no dysplasia, low-grade dysplasia did not increase the risk of colorectal cancer (OR 12.4, p = 0.88), but high-grade dysplasia did increase the risk of colorectal cancer (OR 223.2, p < 0.001). LIMITATIONS: This study was limited by its retrospective review. CONCLUSION: In both ulcerative colitis and Crohn's disease, low-grade dysplasia was not associated with colorectal cancer. High-grade dysplasia was associated with an increased risk of colorectal cancer at time of colectomy. While continued surveillance may be appropriate for low-grade dysplasia, high-grade dysplasia necessitates surgical resection given the high likelihood of colorectal cancer. See Video Abstract at http://links.lww.com/DCR/B887 . DISPLASIA DE ALTO GRADO EN LA ENFERMEDAD INFLAMATORIA INTESTINAL INDICACIN DE COLECTOMA: ANTECEDENTES:Los pacientes con enfermedad inflamatoria intestinal tienen un mayor riesgo de cáncer colorrectal y se recomienda someterse a una mayor vigilancia en comparación con la población general. Actualmente, existe evidencia inadecuada para guiar el manejo de la displasia colónica descubierta durante la valoracion de pacientes con enfermedad inflamatoria intestinal.OBJETIVO:Determinar el riesgo de cáncer colorrectal en pacientes con colitis ulcerosa o enfermedad de Crohn con displasia en la colonoscopia.DISEÑO:Este fue un estudio retrospectivo.AJUSTE:Este estudio se llevó a cabo en un centro de referencia cuaternario de alto volumen con un programa de enfermedad inflamatoria intestinal.PACIENTES:Pacientes con diagnóstico de enfermedad inflamatoria intestinal con colonoscopia dentro de los 6 meses posteriores a la colectomía.PRINCIPALES MEDIDAS DE RESULTADO:Las principales medidas de resultado incluyeron el hallazgo de cáncer colorrectal en el momento de la colectomía.RESULTADOS:Hubo 621 pacientes: 233 con colitis ulcerosa y 388 con enfermedad de Crohn. De los pacientes con colitis ulcerosa, 25 tenían displasia de bajo grado en la colonoscopia y 1 (4%) tenía cáncer colorrectal en la colectomía. Se observó displasia de alto grado antes de la operación en 14 y cáncer colorrectal en 4 (29%) después de la colectomía. En comparación con la ausencia de displasia, la displasia de bajo grado no aumentó el riesgo de cáncer colorrectal (Odds Ratio 1,98, p = 0,47), pero la displasia de alto grado tuvo un mayor riesgo (OR 19,0, p <0,001) de cáncer colorrectal. Para los 7 pacientes con enfermedad de Crohn y displasia de bajo grado, se encontró cáncer colorrectal en 1 (14%) en la colectomía. Se observó displasia de alto grado antes de la operación en 4 pacientes con enfermedad de Crohn y cáncer colorrectal en 3 pacientes (75%) después de la colectomía. En comparación con la ausencia de displasia, la displasia de bajo grado no aumentó el riesgo de cáncer colorrectal (Odds Ratio 12.4, p = 0.88), pero la displasia de alto grado sí aumentó el riesgo de cáncer colorrectal (Odds Ratio 223.2, p <.001).LIMITACIONES:Este estudio estuvo limitado por su revisión retrospectiva. CONCLUSIN: Tanto en la colitis ulcerosa como en la enfermedad de Crohn, la displasia de bajo grado no se asoció con el cáncer colorrectal. La displasia de alto grado se asoció con un mayor riesgo de cáncer colorrectal en el momento de la colectomía. Si bien la vigilancia continua puede ser apropiada para la displasia de bajo grado, la displasia de alto grado requiere resección quirúrgica dada la alta probabilidad de cáncer colorrectal. Consulte Video Resumen en http://links.lww.com/DCR/B887 . (Traducción-Dr Yolanda Colorado ).


Assuntos
Colite Ulcerativa , Neoplasias Colorretais , Doença de Crohn , Doenças Inflamatórias Intestinais , Humanos , Doença de Crohn/complicações , Doença de Crohn/epidemiologia , Doença de Crohn/cirurgia , Estudos Retrospectivos , Colite Ulcerativa/complicações , Colite Ulcerativa/epidemiologia , Colite Ulcerativa/cirurgia , Doenças Inflamatórias Intestinais/complicações , Doenças Inflamatórias Intestinais/epidemiologia , Doenças Inflamatórias Intestinais/cirurgia , Colectomia/efeitos adversos , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/cirurgia , Neoplasias Colorretais/etiologia , Complicações Pós-Operatórias/epidemiologia
10.
J Am Chem Soc ; 144(51): 23405-23420, 2022 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-36513373

RESUMO

Aqueous Zn/MnO2 batteries (AZMOB) with mildly acidic electrolytes hold promise as potential green grid-level energy storage solutions for clean power generation. Mechanistic understanding is critical to advance capacity retention needed by the application but is complex due to the evolution of the cathode solid phases and the presence of dissolved manganese in the electrolyte due to a dissolution-deposition redox process. This work introduces operando multiphase extended X-ray absorption fine structure (EXAFS) analysis enabling simultaneous characterization of both aqueous and solid phases involved in the Mn redox reactions. The methodology was successfully conducted in multiple electrolytes (ZnSO4, Zn(CF3SO3)2, and Zn(CH3COO)2) revealing similar manganese coordination environments but quantitative differences in distribution of Mnn+ species in the solid and solution phases. Complementary Raman spectroscopy was utilized to identify the less crystalline Mn-containing products formed under charge at the cathodes. This was further augmented by transmission electron microscopy (TEM) to reveal the morphology and surface condition of the deposited solids. The results demonstrate an effective approach for bulk-level characterization of poorly crystalline multiphase solids while simultaneously gaining insight into the dissolved transition-metal species in solution. This work provides demonstration of a useful approach toward gaining insight into complex electrochemical mechanisms where both solid state and dissolved active materials are important contributors to redox activity.

11.
Nature ; 611(7934): 43-47, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36323811

RESUMO

Optical atomic clocks are the most accurate measurement devices ever constructed and have found many applications in fundamental science and technology1-3. The use of highly charged ions (HCI) as a new class of references for highest-accuracy clocks and precision tests of fundamental physics4-11 has long been motivated by their extreme atomic properties and reduced sensitivity to perturbations from external electric and magnetic fields compared with singly charged ions or neutral atoms. Here we present the realization of this new class of clocks, based on an optical magnetic-dipole transition in Ar13+. Its comprehensively evaluated systematic frequency uncertainty of 2.2 × 10-17 is comparable with that of many optical clocks in operation. From clock comparisons, we improve by eight and nine orders of magnitude on the uncertainties for the absolute transition frequency12 and isotope shift (40Ar versus 36Ar) (ref. 13), respectively. These measurements allow us to investigate the largely unexplored quantum electrodynamic (QED) nuclear recoil, presented as part of improved calculations of the isotope shift, which reduce the uncertainty of previous theory14 by a factor of three. This work establishes forbidden optical transitions in HCI as references for cutting-edge optical clocks and future high-sensitivity searches for physics beyond the standard model.

13.
Int J Eat Disord ; 55(11): 1621-1626, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36052443

RESUMO

OBJECTIVE: This study explored the preliminary effectiveness of a partial hospitalization program (PHP) for children/adolescents with avoidant/restrictive food intake disorder (ARFID). We evaluated how ARFID symptoms changed from admission to discharge, and collected follow-up data on symptoms and outpatient care following PHP discharge. METHOD: Twenty-two children/adolescents with ARFID (77.3% White, 63.6% female) completed measures assessing ARFID symptomatology at admission and discharge from a PHP for eating disorders. Six months and twelve months following their discharge, participants were contacted to complete study measures again and take part in an interview assessing follow-up care. RESULTS: Paired samples t tests indicated that participants demonstrated increases in weight and decreases in ARFID symptomatology from admission to discharge with medium to large effects. All participants reported receiving some form of outpatient treatment following discharge, with the type of outpatient services varying across participants. Data from the 86% of participants who completed the six-month follow-up and 50% who completed the twelve-month follow-up suggest that participants generally maintained treatment gains following PHP discharge. DISCUSSION: Participants experienced symptom improvements from admission to discharge and appeared to maintain these gains after discharge. These results provide preliminary evidence that PHPs are an effective treatment option for children and adolescents with ARFID. PUBLIC SIGNIFICANCE STATEMENT: This study provides preliminary evidence that intensive, evidence-based PHPs are effective in treating ARFID. Our findings suggest that children and adolescents with ARFID who receive flexible, cognitive-behavioral, family-centered treatment in a PHP for EDs experience improvements in weight and ARFID symptomatology from admission to discharge. Despite receiving variable and nonstandardized outpatient treatment, individuals with ARFID appear to maintain treatment gains 6 and 12 months after discharge in a PHP.


Assuntos
Transtorno Alimentar Restritivo Evitativo , Transtornos da Alimentação e da Ingestão de Alimentos , Criança , Adolescente , Feminino , Humanos , Masculino , Hospital Dia , Estudos Retrospectivos , Transtornos da Alimentação e da Ingestão de Alimentos/diagnóstico , Transtornos da Alimentação e da Ingestão de Alimentos/terapia , Ingestão de Alimentos , Cognição
14.
Proc Natl Acad Sci U S A ; 119(40): e2212777119, 2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36161896

RESUMO

As one of the prevailing energy storage systems, lithium-ion batteries (LIBs) have become an essential pillar in electric vehicles (EVs) during the past decade, contributing significantly to a carbon-neutral future. However, the complete transition to electric vehicles requires LIBs with yet higher energy and power densities. Here, we propose an effective methodology via controlled nanosheet self-assembly to prepare low-tortuosity yet high-density and high-toughness thick electrodes. By introducing a delicate densification in a three-dimensionally interconnected nanosheet network to maintain its vertical architecture, facile electron and ion transports are enabled despite their high packing density. This dense and thick electrode is capable of delivering a high volumetric capacity >1,600 mAh cm-3, with an areal capacity up to 32 mAh cm-2, which is among the best reported in the literature. The high-performance electrodes with superior mechanical and electrochemical properties demonstrated in this work provide a potentially universal methodology in designing advanced battery electrodes with versatile anisotropic properties.

15.
Nano Lett ; 22(16): 6700-6708, 2022 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-35921591

RESUMO

The increasing demands of electronic devices and electric transportation necessitate lithium-ion batteries with simultaneous high energy and power capabilities. However, rate capabilities are often limited in high-loading electrodes due to the lengthy and tortuous ion transport paths with their electrochemical behaviors governed by complicated electrode architectures still elusive. Here, we report the electrode-level tortuosity engineering design enabling improved charge storage kinetics in high-energy electrodes. Both high areal capacity and high-rate capability can be achieved beyond the practical level of mass loadings in electrodes with vertically oriented architectures. The electrochemical properties in electrodes with various architectures were quantitatively investigated through correlating the characteristic time with tortuosity. The lithium-ion transport kinetics regulated by electrode architectures was further studied via combining the three-dimensional electrode architecture visualization and simulation. The tortuosity-controlled charge storage kinetics revealed in this study can be extended to general electrode systems and provide useful design consideration for next-generation high-energy/power batteries.

16.
Nano Lett ; 22(6): 2521-2528, 2022 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-35254075

RESUMO

Because it has been demonstrated to be effective toward faster ion diffusion inside the pore space, low-tortuosity porous architecture has become the focus in thick electrode designs, and other possibilities are rarely investigated. To advance current understanding in the structure-affected electrochemistry and to broaden horizons for thick electrode designs, we present a gradient electrode design, where porous channels are vertically aligned with smaller openings on one end and larger openings on the other. With its 3D morphology carefully visualized by Raman mapping, the electrochemical properties between opposite orientations of the gradient electrodes are compared, and faster energy storage kinetics is found in larger openings and more concentrated active material near the separator. As further verified by simulation, this study on gradient electrode design deepens the knowledge of structure-related electrochemistry and brings perspectives in high-energy battery electrode designs.

17.
Dis Colon Rectum ; 65(11): 1342-1350, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-35001049

RESUMO

BACKGROUND: There is debate regarding the utility of diverting loop ileostomy with IPAA construction in patients requiring colectomy for ulcerative colitis. OBJECTIVE: This study aimed to determine whether the omission of diverting loop ileostomy at the time of IPAA construction increases the risk of complications. DESIGN: This was a retrospective study. SETTINGS: The study was conducted in a high-volume, quaternary referral center with an IBD program. PATIENTS: The patients, who underwent IPAA with or without ileostomy, were diagnosed for ulcerative colitis. MAIN OUTCOME MEASURES: Anastomotic leak rate and pouch failure rates were determined between patients who either had a diverting ileostomy at the time of IPAA creation or had stoma-less IPAA. RESULTS: Of the 414 patients included in this study, 91 had stoma-less IPAA. When compared to IPAA with diverting loop ileostomy, patients with stoma-less IPAA were less likely to be taking prednisone and had decreased blood loss. Short- and long-term outcomes were similar when comparing stoma-less IPAA and IPAA with diverting loop ileostomy, with no significant difference in anastomotic leak rate and long-term pouch failure rates. Diverting loop ileostomy was associated with a 14.6% risk of complication at the time of stoma reversal. LIMITATIONS: The study is limited by its retrospective nature. CONCLUSIONS: The results of this study suggest that the omission of a diverting ileostomy is feasible in select patients undergoing IPAA. Stoma-less IPAA does not have a statistically significant higher risk of anastomotic leak or pouch failure when compared to IPAA with diverting loop ileostomy in properly selected patients. Diverting loop ileostomies have their own risks, which partially offset their perceived safety. See Video Abstract at http://links.lww.com/DCR/B891 .LA ANASTOMÓSIS DE RESERVORIO ILEAL AL ANO SIN ESTOMA NO ESTÁ ASOCIADO CON UN AUMENTO EN LA TASA DE FUGA ANASTOMÓTICA O DISFUNCIÓN DE LA BOLSA A LARGO PLAZO EN PACIENTES CON COLITIS ULCERATIVA. ANTECEDENTES: Existe debate en lo que respecta a la utilidad de efectuar una ileostomía en asa en la construcción de una anastomosis de reservorio ileal al ano en pacientes que requieren colectomía para colitis ulcerativa. OBJETIVO: Determinar si el evitar una ileostomía de derivación en el momento de efectuar una anstomósis de reservorio ileal al ano aumenta el riesgo de complicaciones. DISEO: Estudio retrospectivo. REFERENCIA: Centro de referencia de cuarto nivel de grandes volúmenes con programa de enfermedad inflamatoria intestinal. PACIENTES: Con diagnóstico de colitis ulcerativa sometidos a anastomosis de reservorio ileal al ano con o sin ileostomía derivative. PRINCIPALES MEDIDAS DE RESULTADOS: Tasa de fuga anastomótica y disfunción del reservorio en pacientes sometidos a anastomosis de reservorio ileal al ano con ileostomía derivativa en el mismo evento y aquellos sin derivación de protección. RESULTADOS: De los 414 pacientes incluídos en el estudio, 91 no contaban con ileostomía de protección de la anastomosis del reservorio ileal al ano. Al comprarse con aquellos con ileostomía derivativa, aquellos sin estoma requirieron menor dosis de prednisona y presentaron menor pérdida sanguínea. Los resultados a corto y largo plazo fueron similares al comprar ambos grupos sin haber evidencia significativa de fuga anastomótica o falla del reservorio a largo plazo. La derivación con ileostomía en asa se asoció en un 14.6% de riesgo de complicaciones al efectuar el cierre de la misma. LIMITACIONES: Es una revision retrospectiva. CONCLUSIONES: : Los resultados de este estudio sugieren que la omisión de una ileostomía de protección es posible en pacientes seleccionados sometidos a una anastomosis de reservorio ileoanal. La anastomosis sin derivación de protección no confiere un riesgo estadísticamente significativo de fuga anastomótica o disfunción de la misma al compararse con el procedimiento con estoma derivativo en pacientes seleccionados. Las ileostomías de derivación en asa tienen su propia morbilidad que cuestiona la perfección de su seguridad. Consulte Video Resumen at http://links.lww.com/DCR/B891 . (Traducción- Dr. Miguel Esquivel-Herrera ).


Assuntos
Fístula Anastomótica , Colite Ulcerativa , Fístula Anastomótica/epidemiologia , Fístula Anastomótica/etiologia , Colite Ulcerativa/complicações , Colite Ulcerativa/cirurgia , Humanos , Ileostomia/efeitos adversos , Ileostomia/métodos , Complicações Pós-Operatórias/epidemiologia , Prednisona , Estudos Retrospectivos
18.
Artigo em Inglês | MEDLINE | ID: mdl-34804382

RESUMO

The COVID-19 pandemic has altered innumerable lives. Although recent mass vaccinations offer a glimmer of hope, the rising death toll and new variants continue to dominate the current scenario. As we begin to understand more about SARS-CoV-2 infections, the territory of reinfections with COVID-19 remains unexplored. In this review, we will discuss several aspects of reinfection: (a) How is COVID-19 reinfection characterized? (b) Does prior literature differentiate between reinfection and reactivation? (c) What SARS-CoV-2 strains do the vaccines target and can they protect against new strains? Larger and longer timeline studies are needed to understand reinfection risks. With the ongoing distribution of the SARS-CoV-2 vaccines to provide protection, the understanding of the possibility for SARS-CoV-2 reinfection remains critical. Abbreviations CDC: Centers for Disease ControlSARS-CoV-2: Severe acute respiratory syndrome coronavirus 2COVID-19: Coronavirus disease 2019RT-PCR: Reverse Transcription Polymerase Chain ReactionPASC: Post-Acute Sequelae of SARS-CoV-2 infection.

19.
ACS Cent Sci ; 7(10): 1676-1687, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34729411

RESUMO

Aqueous electrochemical systems suffer from a low energy density due to a small voltage window of water (1.23 V). Using thicker electrodes to increase the energy density and highly concentrated "water-in-salt" (WIS) electrolytes to extend the voltage range can be a promising solution. However, thicker electrodes produce longer diffusion pathways across the electrode. The highly concentrated salts in WIS electrolytes alter the physicochemical properties which determine the transport behaviors of electrolytes. Understanding how these factors interplay to drive complex transport phenomena in WIS batteries with thick electrodes via deterministic analysis on the rate-limiting factors and kinetics is critical to enhance the rate-performance in these batteries. In this work, a multimodal approach-Raman tomography, operando X-ray diffraction refinement, and synchrotron X-ray 3D spectroscopic imaging-was used to investigate the chemical heterogeneity in LiV3O8-LiMn2O4 WIS batteries with thick porous electrodes cycled under different rates. The multimodal results indicate that the ionic diffusion in the electrolyte is the primary rate-limiting factor. This study highlights the importance of fundamentally understanding the electrochemically coupled transport phenomena in determining the rate-limiting factor of thick porous WIS batteries, thus leading to a design strategy for 3D morphology of thick electrodes for high-rate-performance aqueous batteries.

20.
Nano Lett ; 21(13): 5896-5904, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34197125

RESUMO

Thick electrodes, although promising toward high-energy battery systems, suffer from restricted lithium-ion transport kinetics due to prolonged diffusion lengths and tortuous transport pathways. Despite the emerging low-tortuosity designs, capacity retention under higher current densities is still limited. Herein, we employ a modified ice-templating method to fabricate low-tortuosity porous electrodes with tunable wall thickness and channel width and systematically investigate the critical impacts of the fine structural parameters on the thick electrode electrochemistry. While the porous electrodes with thick walls show diminished capability under a C-rate larger than 1.5 C, those with thinner walls could maintain ∼70% capacity under 2.5 C. The superior capacity retention is ascribed to the fast diffusion into the thin lamellar walls compared with their thicker counterparts. This study provides deeper insights into structure-affected electrochemistry and opens up new perspective of 3D porous architectural designs for high-energy and high-power electrodes.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...