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1.
Nature ; 573(7775): 558-562, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31554980

RESUMEN

High-pressure transitions are thought to modify hydrogen molecules to a molecular metallic solid and finally to an atomic metal1, which is predicted to have exotic physical properties and the topology of a two-component (electron and proton) superconducting superfluid condensate2,3. Therefore, understanding such transitions remains an important objective in condensed matter physics4,5. However, measurements of the crystal structure of solid hydrogen, which provides crucial information about the metallization of hydrogen under compression, are lacking for most high-pressure phases, owing to the considerable technical challenges involved in X-ray and neutron diffraction measurements under extreme conditions. Here we present a single-crystal X-ray diffraction study of solid hydrogen at pressures of up to 254 gigapascals that reveals the crystallographic nature of the transitions from phase I to phases III and IV. Under compression, hydrogen molecules remain in the hexagonal close-packed (hcp) crystal lattice structure, accompanied by a monotonic increase in anisotropy. In addition, the pressure-dependent decrease of the unit cell volume exhibits a slope change when entering phase IV, suggesting a second-order isostructural phase transition. Our results indicate that the precursor to the exotic two-component atomic hydrogen may consist of electronic transitions caused by a highly distorted hcp Brillouin zone and molecular-symmetry breaking.


Asunto(s)
Hidrógeno/química , Modelos Moleculares , Presión , Electrónica , Difracción de Neutrones , Transición de Fase , Difracción de Rayos X
2.
J Neurosci ; 43(31): 5656-5667, 2023 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-37451980

RESUMEN

The parabrachial nuclear complex (PBN) is a nexus for aversion and for the sensory and affective components of pain perception. We have previously shown that during chronic pain PBN neurons in anesthetized rodents have amplified activity. We report a method to record from PBN neurons of behaving, head-restrained mice while applying reproducible noxious stimuli. We find that both spontaneous and evoked activity are higher in awake animals compared with urethane anesthetized mice. Fiber photometry of calcium responses from calcitonin-gene-related peptide-expressing PBN neurons demonstrates that these neurons respond to noxious stimuli. In both males and females with neuropathic or inflammatory pain, responses of PBN neurons remain amplified for at least 5 weeks, in parallel with increased pain metrics. We also show that PBN neurons can be rapidly conditioned to respond to innocuous stimuli after pairing with noxious stimuli. Finally, we demonstrate that changes in PBN neuronal activity are correlated with changes in arousal, measured as changes in pupil area.SIGNIFICANCE STATEMENT The parabrachial complex is a nexus of aversion, including pain. We report a method to record from parabrachial nucleus neurons of behaving mice while applying reproducible noxious stimuli. This allowed us to track parabrachial activity over time in animals with neuropathic or inflammatory pain. It also allowed us to show that the activity of these neurons correlates with arousal states and that these neurons can be conditioned to respond to innocuous stimuli.


Asunto(s)
Dolor Crónico , Núcleos Parabraquiales , Masculino , Femenino , Ratones , Animales , Núcleos Parabraquiales/fisiología , Nocicepción , Vigilia , Péptido Relacionado con Gen de Calcitonina/metabolismo
3.
Cancer ; 130(7): 1101-1111, 2024 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-38100619

RESUMEN

BACKGROUND: Many parents of children with advanced cancer report curative goals and continue intensive therapies that can compound symptoms and suffering. Factors that influence parents to choose palliation as the primary treatment goal are not well understood. The objective of this study was to examine experiences impacting parents' report of palliative goals adjusted for time. The authors hypothesized that awareness of poor prognosis, recall of oncologists' prognostic disclosure, intensive treatments, and burdensome symptoms and suffering would influence palliative goal-setting. METHODS: The authors collected prospective, longitudinal surveys from parents of children with relapsed/refractory neuroblastoma at nine pediatric cancer centers across the United States, beginning at relapse and continuing every 3 months for 18 months or until death. Hypothesized covariates were examined for possible associations with parental report of palliative goals. Generalized linear mixed models were used to evaluate factors associated with parents' report of palliative goals at different time points. RESULTS: A total of 96 parents completed surveys. Parents were more likely to report a primary goal of palliation when they recalled communication about prognosis by their child's oncologist (odds ratio [OR], 52.48; p = .010). Treatment intensity and previous ineffective therapeutic regimens were not associated with parents' report of palliative goals adjusted for time. A parent who reported new suffering for their child was less likely to report palliative goals (OR, 0.13; p = .008). CONCLUSIONS: Parents of children with poor prognosis cancer may not report palliative goals spontaneously in the setting of treatment-related suffering. Prognostic communication, however, does influence palliative goal-setting. Evidence-based interventions are needed to encourage timely, person-centered prognostic disclosure in the setting of advanced pediatric cancer. PLAIN LANGUAGE SUMMARY: Many parents of children with poor-prognosis cancer continue to pursue curative treatments that may worsen symptoms and suffering. Little is known about which factors influence parents to choose palliative care as their child's main treatment goal. To explore this question, we asked parents of children with advanced neuroblastoma across the United States to complete multiple surveys over time. We found that the intensity of treatment, number of treatments, and suffering from treatment did not influence parents to choose palliative goals. However, when parents remembered their child's oncologist talking about prognosis, they were more likely to choose palliative goals of care.


Asunto(s)
Neuroblastoma , Cuidados Paliativos , Niño , Humanos , Objetivos , Estudios Prospectivos , Recurrencia Local de Neoplasia/terapia , Neuroblastoma/terapia , Padres , Encuestas y Cuestionarios , Estudios Longitudinales
4.
J Fam Issues ; 45(3): 674-696, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38571758

RESUMEN

Premarital sex predicts divorce, but we do not know why. Scholars have attributed the relationship to factors such as differences in beliefs and values, but these explanations have not been tested. It is further unclear how this relationship changes by number of sexual partners, or differs by gender. We re-examine this relationship with event history models using data from the National Longitudinal Study of Adolescent to Adult Health. Models include measures of adolescent beliefs and values, religious background, and personal characteristics, as well as approximate number of premarital sexual partners in young adulthood. We find the relationship between premarital sex and divorce is highly significant and robust even when accounting for early-life factors. Compared to people with no premarital partners other than eventual spouses, those with nine or more partners exhibit the highest divorce risk, followed by those with one to eight partners. There is no evidence of gender differences.

5.
Cancer ; 129(12): 1873-1884, 2023 06 15.
Artículo en Inglés | MEDLINE | ID: mdl-36943896

RESUMEN

BACKGROUND: Hyperleukocytosis in patients with acute myeloid leukemia (AML) has been associated with worse outcomes. For cytoreduction, leukapheresis has been used but its clinical utility is unknown, and low-dose cytarabine (LD-cytarabine) is used as an alternative method. METHODS: Children with newly diagnosed AML treated between 1997 and 2017 in institutional protocols were studied. Hyperleukocytosis was defined as a leukocyte count of ≥100 × 109 /L at diagnosis. Clinical characteristics, early complications, survival data, and effects of cytoreductive methods were reviewed. Among 324 children with newly diagnosed AML, 49 (15.1%) presented with hyperleukocytosis. Initial management of hyperleukocytosis included leukapheresis or exchange transfusion (n = 16, considered as one group), LD-cytarabine (n = 18), hydroxyurea (n = 1), and no leukoreduction (n = 14). RESULTS: Compared with patients who received leukapheresis, the percentage decrease in leukocyte counts following intervention was greater among those who received LD-cytarabine (48% vs. 75%; p = .02), with longer median time from diagnosis to initiation of protocol therapy (28.1 vs. 95.2 hours; p < .001). The incidence of infection was higher in patients (38%) who had leukapheresis than those who receive LD-cytarabine (0%) or leukoreduction with protocol therapy (14%) (p = .008). No differences were noted in the outcomes among the intervention groups. Although patients with hyperleukocytosis had higher incidences of pulmonary and metabolic complications than did those without, no early deaths occurred, and the complete remission, event-free survival, overall survival rates, and outcomes of both groups were similar. CONCLUSION: LD-cytarabine treatment appears to be a safe and effective means of cytoreduction for children with AML and hyperleukocytosis.


Asunto(s)
Procedimientos Quirúrgicos de Citorreducción , Leucemia Mieloide Aguda , Humanos , Niño , Procedimientos Quirúrgicos de Citorreducción/efectos adversos , Leucocitosis/terapia , Leucocitosis/epidemiología , Leucocitosis/etiología , Leucemia Mieloide Aguda/complicaciones , Leucemia Mieloide Aguda/terapia , Leucemia Mieloide Aguda/diagnóstico , Recuento de Leucocitos , Leucaféresis/métodos , Citarabina
6.
Dis Colon Rectum ; 66(10): 1347-1358, 2023 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-36649145

RESUMEN

BACKGROUND: Laparoscopic resection for colon cancer has not been associated with improvements in oncological outcomes in comparison to open resection. Robotic resections are associated with increased lymph node yield and radicality of mesenteric resection in patients with right-sided tumors. It is unclear whether lymph node yield is higher in robotic resections in other parts of the colon and whether higher lymph node yield is associated with improved survival. OBJECTIVE: To compare survival rates between robotic, laparoscopic, and open resections in a large cohort of patients with nonmetastatic colon cancer. DESIGN: This is a retrospective observational study. SETTING: A single comprehensive cancer center. PATIENTS: Patients who underwent resection of nonmetastatic primary colon cancer between January 2006 and December 2018. MAIN OUTCOME MEASURES: Univariable and multivariable models were used to identify predictors of disease-free and overall survival. Lymph node yield and perioperative outcomes were compared between operative approaches. RESULTS: There were 2398 patients who met the inclusion criteria: 699 (29%) underwent open, 824 (34%) underwent laparoscopic, and 875 (36%) underwent robotic resection. The median follow-up was 3.8 years (45.4 months). Robotic surgery was associated with higher lymph node yield and radicality of mesenteric resection. On multivariable analysis, the surgical approach was not associated with a difference in disease-free or overall survival. Minimally invasive colectomy was associated with fewer complications and shorter length of stay in comparison to open surgery. In a direct comparison between the 2 minimally invasive approaches, robotic colectomy was associated with fewer complications, shorter length of stay, and lower conversion rate than laparoscopy. LIMITATIONS: This was a single-center retrospective study. CONCLUSIONS: Our data indicate that the 3 surgical approaches are similarly effective in treating primary resectable colon cancer and that differences in outcomes are observed primarily in the early postoperative period. See Video Abstract at http://links.lww.com/DCR/C115 . COMPARACIN DE RESECCIONES ROBTICAS, LAPAROSCPICAS Y ABIERTAS DE CNCER DE COLON NO METASTSICO: ANTECEDENTES:La resección laparoscópica para el cáncer de colon no se ha asociado con mejoras en los resultados oncológicos en comparación con la resección abierta. Las resecciones robóticas se asocian con un mayor rendimiento de los ganglios linfáticos y la radicalidad de la resección mesentérica en pacientes con tumores del lado derecho. No está claro si la cosecha ganglionar es mayor en las resecciones robóticas en otras partes del colon y si un mayor rendimiento de los ganglios linfáticos se asocia con una mejor supervivencia.OBJETIVO:Comparar las tasas de supervivencia entre resecciones robóticas, laparoscópicas y abiertas en una gran cohorte de pacientes con cáncer de colon no metastásico.DISEÑO:Este es un estudio observacional retrospectivo.ESCENARIO:Este estudio se realizó en un único centro oncológico integral.PACIENTES:Pacientes que se sometieron a resección de cáncer de colon primario no metastásico entre enero de 2006 y diciembre de 2018.PRINCIPALES MEDIDAS DE RESULTADO:Se utilizaron modelos univariables y multivariables para identificar predictores de supervivencia libre de enfermedad y global. La cosecha ganglionar y los resultados perioperatorios se compararon entre los abordajes quirúrgicos.RESULTADOS:Hubo 2398 pacientes que cumplieron con los criterios de inclusión: 699 (29%) se sometieron a cirugía abierta, 824 (34%) se sometieron a resección laparoscópica y 875 (36%) se sometieron a resección robótica. La mediana de seguimiento fue de 3,8 años (45,4 meses). La cirugía robótica se asoció con una mayor cosecha ganglionar y la radicalidad de la resección mesentérica. En el análisis multivariable, el abordaje quirúrgico no se asoció con una diferencia en la supervivencia general o libre de enfermedad. La colectomía mínimamente invasiva se asoció con menos complicaciones y una estancia más corta en comparación con la cirugía abierta. En una comparación directa entre los dos enfoques mínimamente invasivos, la colectomía robótica se asoció con menos complicaciones, una estancia más corta y una tasa de conversión más baja que la laparoscopia.LIMITACIONES:Este fue un estudio retrospectivo de un solo centro.CONCLUSIONES:Nuestros datos indican que los tres enfoques quirúrgicos son igualmente efectivos en el tratamiento del cáncer de colon resecable primario y que las diferencias en los resultados se observan principalmente en el período posoperatorio temprano. Consulte Video Resumen en http://links.lww.com/DCR/C115 . (Traducción-Dr. Felipe Bellolio ).


Asunto(s)
Neoplasias del Colon , Laparoscopía , Procedimientos Quirúrgicos Robotizados , Humanos , Estudios Retrospectivos , Resultado del Tratamiento , Neoplasias del Colon/cirugía , Neoplasias del Colon/patología , Colectomía , Complicaciones Posoperatorias/cirugía
7.
Graefes Arch Clin Exp Ophthalmol ; 261(3): 709-714, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36289075

RESUMEN

PURPOSE: There have been disparate outcomes in the few studies that have looked at anatomic success and visual acuity (VA) in chronic retinal rhegmatogenous detachment (RRD) repair. Chronic retinal detachments (RD) without a posterior vitreous detachment (PVD) occur in young myopes often secondary to an atrophic hole. These patients are often asymptomatic, and studies report good surgical anatomic results. However, chronic RD with a PVD is symptomatic but presents late due to patient compliance. This paper aims to evaluate this lesser-studied chronic macula-off RD with PVD. METHODS: After obtaining Institutional Review Board (IRB) approval, patients who had undergone surgical intervention for all diagnosis codes of RD were identified in the Denver Health Medical Center database. Medical records were reviewed, and patients found to have open-globe injuries, tractional RD due to proliferative diabetic retinopathy, macula-on detachments, and RD due to previous ocular surgery were excluded. Similarly, patients without PVD were also excluded. A total of 37 patients with PVD-type chronic macula-off RD were thus identified and preoperative characteristics, surgical intervention, and complications were analyzed. RESULTS: The average patient age was 53.8 years. The length of RRD duration ranged from 30 to 365 days (mean 136.7 days). Twenty-six (70.3% patients had proliferative vitreoretinopathy (PVR) grade C or greater. Initial anatomic success-defined as re-attachment after one surgery-was 54.1%. The final attachment was 94.6%. Fifteen of 37 (40.5%) of the patients had issues with drop adherence, positioning, or missing post-operative appointments. CONCLUSION: Chronic macula-off RD with a PVD should be identified as it is associated with much lower rates of initial re-attachment. Socioeconomic factors likely are the driving factor for patients with PVD-type chronic macula-off RD to present late, struggle with positioning, and have difficulty with follow-up and drop compliance. These extended periods without treatment then lead to high rates of PVR and poor initial anatomic success. However, repair of PVD-type chronic macula-off RD should still be pursued as final anatomic success is high.


Asunto(s)
Desprendimiento de Retina , Vitreorretinopatía Proliferativa , Desprendimiento del Vítreo , Humanos , Persona de Mediana Edad , Desprendimiento de Retina/diagnóstico , Desprendimiento de Retina/cirugía , Desprendimiento de Retina/etiología , Retina , Cuerpo Vítreo , Curvatura de la Esclerótica , Vitreorretinopatía Proliferativa/complicaciones , Desprendimiento del Vítreo/cirugía , Vitrectomía/métodos , Estudios Retrospectivos
8.
Proc Natl Acad Sci U S A ; 117(27): 15437-15442, 2020 07 07.
Artículo en Inglés | MEDLINE | ID: mdl-32571925

RESUMEN

Ice amorphization, low- to high-density amorphous (LDA-HDA) transition, as well as (re)crystallization in ice, under compression have been studied extensively due to their fundamental importance in materials science and polyamorphism. However, the nature of the multiple-step "reverse" transformation from metastable high-pressure ice to the stable crystalline form under reduced pressure is not well understood. Here, we characterize the rate and temperature dependence of the structural evolution from ice VII to ice I recovered at low pressure (∼5 mTorr) using in situ time-resolved X-ray diffraction. Unlike previously reported ice VII (or ice VIII)→LDA→ice I transitions, we reveal three temperature-dependent successive transformations: conversion of ice VII into HDA, followed by HDA-to-LDA transition, and then crystallization of LDA into ice I. Significantly, the temperature-dependent characteristic times indicate distinctive thermal activation mechanisms above and below 110-115 K for both ice VIII-to-HDA and HDA-to-LDA transitions. Large-scale molecular-dynamics calculations show that the structural evolution from HDA to LDA is continuous and involves substantial movements of the water molecules at the nanoscale. The results provide a perspective on the interrelationship of polyamorphism and unravel its underpinning complexities in shaping ice-transition kinetic pathways.

9.
J Public Health (Oxf) ; 44(2): e192-e202, 2022 06 27.
Artículo en Inglés | MEDLINE | ID: mdl-33837430

RESUMEN

BACKGROUND: Increasing the price of alcohol reduces alcohol consumption and harm. The role of food complementarity, transaction costs and inflation on alcohol demand are determined and discussed in relation to alcohol price policies. METHODS: UK Biobank (N = 502,628) was linked by region to retail price quotes for the years 2007 to 2010. The log residual food and alcohol prices, and alcohol availability were regressed onto log daily alcohol consumption. Model standard errors were adjusted for clustering by region. RESULTS: Associations with alcohol consumption were found for alcohol price (ß = -0.56, 95% CI, -0.92 to -0.20) and availability (ß = 0.06, 95% CI, 0.04 to 0.07). Introducing, food price reduced the alcohol price consumption association (ß = -0.26, 95% CI, -0.50 to -0.03). Alcohol (B = 0.001, 95% CI, 0.0004 to 0.001) and food (B = 0.001, 95% CI, 0.0005 to 0.0006) price increased with time and were associated (ρ = 0.57, P < 0.001). CONCLUSION: Alcohol and food are complements, and the price elasticity of alcohol reduces when the effect of food price is accounted for. Transaction costs did not affect the alcohol price consumption relationship. Fixed alcohol price policies are susceptible to inflation.


Asunto(s)
Bebidas Alcohólicas , Comercio , Anciano , Consumo de Bebidas Alcohólicas/epidemiología , Bancos de Muestras Biológicas , Costos y Análisis de Costo , Estudios Transversales , Humanos , Política Pública , Reino Unido/epidemiología
10.
BMC Public Health ; 22(1): 1361, 2022 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-35840948

RESUMEN

BACKGROUND: COVID-19 has caused over 305 million infections and nearly 5.5 million deaths globally. With complete eradication unlikely, organizations will need to evaluate their risk and the benefits of mitigation strategies, including the effects of regular asymptomatic testing. We developed a web application and R package that provides estimates and visualizations to aid the assessment of organizational infection risk and testing benefits to facilitate decision-making, which combines internal and community information with malleable assumptions. RESULTS: Our web application, covidscreen, presents estimated values of risk metrics in an intuitive graphical format. It shows the current expected number of active, primarily community-acquired infections among employees in an organization. It calculates and explains the absolute and relative risk reduction of an intervention, relative to the baseline scenario, and shows the value of testing vaccinated and unvaccinated employees. In addition, the web interface allows users to profile risk over a chosen range of input values. The performance and output are illustrated using simulations and a real-world example from the employee testing program of a pediatric oncology specialty hospital. CONCLUSIONS: As the COVID-19 pandemic continues to evolve, covidscreen can assist organizations in making informed decisions about whether to incorporate covid test based screening as part of their on-campus risk-mitigation strategy. The web application, R package, and source code are freely available online (see "Availability of data and materials").


Asunto(s)
COVID-19 , Aplicaciones Móviles , COVID-19/diagnóstico , COVID-19/prevención & control , Prueba de COVID-19 , Niño , Humanos , Tamizaje Masivo , Pandemias/prevención & control
11.
Hippocampus ; 31(1): 102-114, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33038042

RESUMEN

Adult neurogenesis has been implicated in learning and memory of complex spatial environments. However, new neurons also play a role in nonmnemonic behavior, including the stress response and attention shifting. Many commonly used spatial tasks are very simple, and unsuitable for detecting neurogenesis effects, or are aversively motivated, making it difficult to dissociate effects on spatial learning and memory from effects on stress. We have therefore created a novel complex spatial environment, the flex maze, to enable reward-mediated testing of spatial learning in a flexibly configurable labyrinth. Using a pharmacogenetic method to completely inhibit neurogenesis in adulthood, we found that rats lacking new neurons (TK rats) and wild type controls completed and remembered most mazes equally well. However, control rats were slower to complete peppermint-scented mazes than other mazes, while neurogenesis-deficient rats showed no effect of mint on maze behavior, completing these mazes significantly faster than control rats. Additional testing found that wild type and TK rats showed similar detection of, avoidance of, and glucocorticoid response to the mint odor. These results suggest that spatial learning and memory in a labyrinth task is unaffected by the loss of new neurons, but that these cells affect the ability of an aversive stimulus to distract rats from completing the maze.


Asunto(s)
Aprendizaje Espacial , Animales , Hipocampo , Aprendizaje por Laberinto , Neurogénesis , Neuronas , Ratas , Memoria Espacial
12.
Am J Epidemiol ; 190(8): 1504-1509, 2021 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-33406533

RESUMEN

Since its global emergence in 2020, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused multiple epidemics in the United States. When medical treatments for the virus were still emerging and a vaccine was not yet available, state and local governments sought to limit its spread by enacting various social-distancing interventions, such as school closures and lockdowns; however, the effectiveness of these interventions was unknown. We applied an established, semimechanistic Bayesian hierarchical model of these interventions to the spread of SARS-CoV-2 from Europe to the United States, using case fatalities from February 29, 2020, up to April 25, 2020, when some states began reversing their interventions. We estimated the effects of interventions across all states, contrasted the estimated reproduction numbers before and after lockdown for each state, and contrasted the predicted number of future fatalities with the actual number of fatalities as a check of the model's validity. Overall, school closures and lockdowns were the only interventions modeled that had a reliable impact on the time-varying reproduction number, and lockdown appears to have played a key role in reducing that number to below 1.0. We conclude that reversal of lockdown without implementation of additional, equally effective interventions will enable continued, sustained transmission of SARS-CoV-2 in the United States.


Asunto(s)
Número Básico de Reproducción , COVID-19/epidemiología , COVID-19/prevención & control , Control de Enfermedades Transmisibles/estadística & datos numéricos , Cuarentena/estadística & datos numéricos , Teorema de Bayes , Control de Enfermedades Transmisibles/métodos , Europa (Continente)/epidemiología , Humanos , Distanciamiento Físico , SARS-CoV-2 , Estados Unidos/epidemiología
13.
Phys Rev Lett ; 126(17): 175501, 2021 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-33988447

RESUMEN

High-pressure chemistry is known to inspire the creation of unexpected new classes of compounds with exceptional properties. Here, we employ the laser-heated diamond anvil cell technique for synthesis of a Dirac material BeN_{4}. A triclinic phase of beryllium tetranitride tr-BeN_{4} was synthesized from elements at ∼85 GPa. Upon decompression to ambient conditions, it transforms into a compound with atomic-thick BeN_{4} layers interconnected via weak van der Waals bonds and consisting of polyacetylene-like nitrogen chains with conjugated π systems and Be atoms in square-planar coordination. Theoretical calculations for a single BeN_{4} layer show that its electronic lattice is described by a slightly distorted honeycomb structure reminiscent of the graphene lattice and the presence of Dirac points in the electronic band structure at the Fermi level. The BeN_{4} layer, i.e., beryllonitrene, represents a qualitatively new class of 2D materials that can be built of a metal atom and polymeric nitrogen chains and host anisotropic Dirac fermions.

14.
Proc Natl Acad Sci U S A ; 115(9): 2010-2015, 2018 02 27.
Artículo en Inglés | MEDLINE | ID: mdl-29440411

RESUMEN

Water is an extraordinary liquid, having a number of anomalous properties which become strongly enhanced in the supercooled region. Due to rapid crystallization of supercooled water, there exists a region that has been experimentally inaccessible for studying deeply supercooled bulk water. Using a rapid decompression technique integrated with in situ X-ray diffraction, we show that a high-pressure ice phase transforms to a low-density noncrystalline (LDN) form upon rapid release of pressure at temperatures of 140-165 K. The LDN subsequently crystallizes into ice-Ic through a diffusion-controlled process. Together with the change in crystallization rate with temperature, the experimental evidence indicates that the LDN is a low-density liquid (LDL). The measured X-ray diffraction data show that the LDL is tetrahedrally coordinated with the tetrahedral network fully developed and clearly linked to low-density amorphous ices. On the other hand, there is a distinct difference in structure between the LDL and supercooled water or liquid water in terms of the tetrahedral order parameter.

15.
Prev Sci ; 22(4): 475-491, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33237552

RESUMEN

Co-production affords an intervention's target population the opportunity to participate in intervention theory decision-making during the development process. This addresses the over-reliance on developing interventions through academic theories which can be devoid of contextual understanding and result in challenges to implementing school-based health programmes. There is an emergent empirical literature on co-producing school-based health interventions, but an understanding of appropriate theoretical types and processes and stakeholders' experiences is lacking. Through the conduct of a systematic review, this study seeks to understand the types and underlying theories and processes for co-production in school-based health interventions with students aged 11-16. A thematic synthesis explored stakeholders' experiences of the different types of co-production. A systematic search of five electronic bibliographic databases, citation tracking of included studies, and consultation with an expert international panel were employed. Of 27,433 unique papers, 30 papers representing 22 studies were retained to describe types, and 23 papers of 18 studies used to synthesise stakeholders' experiences. Three types were identified: external, individual-level, and system-level capacity-building. Whilst this review showed variability in co-production types, stakeholders involved and processes, shared functions were identified. Students', school staff, facilitators' and researchers' experiences in terms of acceptability, feasibility and undertaking decision-making are discussed. Recommendations for conceptualising and reporting co-production and process evaluations of co-produced school-based health interventions are highlighted.


Asunto(s)
Servicios de Salud Escolar , Instituciones Académicas , Estudiantes , Adolescente , Niño , Humanos
16.
Ann Plast Surg ; 86(2): 182-187, 2021 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-32826439

RESUMEN

BACKGROUND AND OBJECTIVES: Delayed arterial thrombus causing loss of a cutaneous free flap at or beyond 6 months is a rare phenomenon. The purpose of this report is to describe 2 cases of arterial compromise requiring medical and surgical intervention at or beyond 6 months after radial forearm free flap (RFFF) phalloplasty and to define the phenomenon of ultradelayed arterial thrombosis. METHODS: Patient 1 is a 44-year-old transmale who presented with pulselessness, pallor, and hypersensitivity of his neophallus 10 years status post-RFFF phalloplasty using a saphenous vein interposition graft (SVIG) between the superficial femoral artery (SFA) and radial artery (RA). Patient 2 is a 35-year-old transmale who presented with similar complaints 6 months status post-RFFF phalloplasty with the same vascular connections as above. RESULTS: Patient 1 was found to have an arterial thrombus distal to the SFA-SVIG anastomosis requiring catheter-directed thrombolysis with tissue plasminogen activator, resulting in partial loss limited to the distal three fourths of the shaft. Patient 2 was also found to have an arterial thrombus distal to the SFA-SVIG anastomosis requiring catheter-directed thrombolysis with tissue plasminogen activator and common femoral artery CFA-RA bypass, resulting in partial loss limited to the neoglans. CONCLUSIONS: Ultradelayed arterial thrombosis is a rare phenomenon requiring urgent intervention. The exact causes of this phenomenon, whether mechanical or physiological or both, have yet to be fully elucidated but it is hypothesized that the original anastomosis may continue to serve as the critical blood supply to its flap as far as 10 years after surgery.


Asunto(s)
Colgajos Tisulares Libres , Trombosis , Adulto , Humanos , Isquemia , Masculino , Pene/cirugía , Trombosis/etiología , Trombosis/cirugía , Activador de Tejido Plasminógeno
17.
Sociol Relig ; 82(3): 332-356, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34149869

RESUMEN

The family and denominational factors influencing intergenerational religious transmission have been examined in a substantial body of work. Despite research identifying religious ideology as a salient aspect of American religion, however, its role in religious transmission remains unexplored. In this study, I use the National Study of Youth and Religion to test whether children's worship attendance and centrality of faith in young adulthood differ based on whether their parents identify as religiously liberal, moderate, conservative, or none of these. I further test whether the strength of the relationship between parent and child religiosity differs between ideological groups. The primary finding is that religious transmission is stronger among children of religious conservatives than for any other group, while the other groups do not differ significantly from one another. These differences in transmission are largely explained by religious conservative parenting approaches, congregational involvement, and most importantly, more intensive religious socialization.

18.
Phys Rev Lett ; 125(15): 155702, 2020 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-33095607

RESUMEN

High-pressure metallic ß-Sn silicon (Si-II), depending on temperature, decompression rate, stress, etc., may transform to diverse metastable forms with promising semiconducting properties under decompression. However, the underlying mechanisms governing the different transformation paths are not well understood. Here, two distinctive pathways, viz., a thermally activated crystal-crystal transition and a mechanically driven amorphization, were characterized under rapid decompression of Si-II at various temperatures using in situ time-resolved x-ray diffraction. Under slow decompression, Si-II transforms to a crystalline bc8/r8 phase in the pressure range of 4.3-9.2 GPa through a thermally activated process where the overdepressurization and the onset transition strain are strongly dependent on decompression rate and temperature. In comparison, Si-II collapses structurally to an amorphous form at around 4.3 GPa when the volume expansion approaches a critical strain via rapid decompression beyond a threshold rate. The occurrence of the critical strain indicates a limit of the structural metastability of Si-II, which separates the thermally activated and mechanically driven transition processes. The results show the coupled effect of decompression rate, activation barrier, and thermal energy on the adopted transformation paths, providing atomistic insight into the competition between equilibrium and nonequilibrium pathways and the resulting metastable phases.

19.
J Gen Intern Med ; 35(6): 1743-1750, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32060717

RESUMEN

BACKGROUND: Prior research on the restaurant environment and obesity risk is limited by cross-sectional data and a focus on specific geographic areas. OBJECTIVE: To measure the impact of changes in chain restaurant calories over time on body mass index (BMI). DESIGN: We used a first-difference model to examine whether changes from 2012 to 2015 in chain restaurant calories per capita were associated with percent changes in BMI. We also examined differences by race and county income, restaurant type, and initial body weight categories. SETTING: USA (207 counties across 39 states). PARTICIPANTS: 447,873 adult patients who visited an athenahealth medical provider in 2012 and 2015 where BMI was measured. MAIN OUTCOMES MEASURED: Percent change in objectively measured BMI from 2012 to 2015. RESULTS: Across all patients, changes in chain restaurant calories per capita were not associated with percent changes in BMI. For Black or Hispanic adults, a 10% increase in exposure to chain restaurant calories per capita was associated with a 0.16 percentage-point increase in BMI (95% CI 0.03, 0.30). This translates into a predicted weight increase of 0.89 pounds (or a 0.53% BMI increase) for an average weight woman at the 90th percentile of increases in the restaurant environment from 2012 to 2015 versus an increase 0.39 pounds (or 0.23% BMI increase) at the 10th percentile. Greater increases in exposure to chain restaurant calories also significantly increased BMI for Black or Hispanic adults receiving healthcare services in lower-income counties (0.26, 95% CI 0.04, 0.49) and with overweight/obesity (0.16, 95% CI 0.04, 0.29). LIMITATIONS: Generalizability to non-chain restaurants is unknown and the sample of athenahealth patients is relatively homogenous. CONCLUSIONS: Increased exposure to chain restaurant calories per capita was associated with increased weight gain among Black or Hispanic adults.


Asunto(s)
Obesidad , Restaurantes , Adulto , Índice de Masa Corporal , Estudios Transversales , Ingestión de Energía , Femenino , Humanos , Obesidad/epidemiología , Sobrepeso
20.
Exp Eye Res ; 195: 108040, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32360553

RESUMEN

Animal studies suggest that the retinal dysfunction in diabetic subjects that precedes overt clinical vasculopathy may be due to a retinal dopamine deficit. We analyzed levels of dopamine (DA) and its primary metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC), in the vitreous of diabetic and non-diabetic human subjects. Adult patients undergoing pars plana vitrectomy for non-hemorrhagic indications were prospectively recruited from the Emory Eye Center in Atlanta, GA. Vitreous samples were analyzed using high performance liquid chromatography (HPLC) to measure levels of DOPAC and DA in the vitreous specimens. Vitreous samples from 9 diabetic patients and 20 from non-diabetic patients were analyzed. No eyes had apparent diabetic retinopathy. Mean normalized DA concentration in vitreous of diabetic subjects was 0.76 ± 0.12 pg/µL vs. 0.73 ± 0.08 pg/µL in non-diabetic vitreous (p = 0.849). DOPAC concentration was 8.84 ± 0.74 pg/µL in vitreous of diabetic subjects vs. 9.22 ± 0.56 pg/µL in vitreous of non-diabetic subjects (p = 0.691). No difference was observed in the concentrations of DA and DOPAC in the vitreous of people without diabetes compared to those with diabetes without retinopathy.


Asunto(s)
Diabetes Mellitus/metabolismo , Retinopatía Diabética/metabolismo , Dopamina/metabolismo , Cuerpo Vítreo/metabolismo , Biomarcadores/metabolismo , Humanos
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