RESUMO
Self-assembly processes are widely used in nature to form hierarchically organized structures, prompting us to investigate such processes at the macroscopic scale. We report an unprecedented approach toward the self-assembly of alkyl-fullerene (C60) derivatives into a hexagonal array of hemispherical microparticles akin to the morphology of a compound eye. The method includes casting solvated alkyl-C60compound on an air/water interface followed by controlled evaporation of the solvent under atmosphere-sealed conditions. This leads to the formation of a thin film floating on water with a diameter of up to 1.3 centimeters and exhibiting a hexagonally-packed hemispherical structure with a diameter of approximately 38µm. Various measurements of the formed film reveal that amorphousness is necessary for suppressing uncontrollable crystallization, which affects the microparticle size and film formation mechanism. We tested the feasibility of this approach for the self-assembly of a relatively common C60derivative, [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM), resulting in the formation of a film with a similar pattern of hexagonally-packed larger microparticles approximately 152µm in size of diameter.
RESUMO
Metal-oxide nanocomposites (MONs) are of pivotal importance as electrode materials, yet lack a guiding principle to tune their phase texture. Here we report that the phase texture of MONs can be tuned at the nanoscale by controlling the nanophase separation of precursor alloys. In situ transmission electron microscopy (in situ TEM) has demonstrated that a MON material of platinum (Pt) and cerium oxide (CeO2) is obtained through promoted nanophase separation of a Pt5Ce precursor alloy in an atmosphere containing oxygen (O2) and carbon monoxide (CO). The Pt-CeO2 MON material comprised an alternating stack of nanometre-thick layers of Pt and CeO2 in different phase textures ranging from lamellae to mazes, depending on the O2 fraction in the atmosphere. Mathematical simulations have demonstrated that the phase texture of MONs originates from a balance in the atomic diffusions across the alloy precursor, which is controllable by the O2 fraction, temperature, and composition of the precursor alloys.
RESUMO
OBJECTIVES: Adenomyosis is associated with unfavorable perinatal outcomes, and recent case reports show that some women with adenomyosis experience pain at the adenomyosis lesion during pregnancy and have detrimental perinatal outcomes. This study aimed to clarify the clinical characteristics of this pain and perinatal outcomes associated with this phenomenon. METHODS: This was a single-center retrospective analysis of pregnant women with adenomyosis. The incidence of pain onset at adenomyosis lesions, defined as persistent pain at the adenomyosis site with administration of analgesics for pain relief, and its association with perinatal outcomes were analyzed. RESULTS: Among 91 singleton pregnancies with adenomyosis, 12 pregnancies (13.2â¯%) presented with pain. One pregnancy resulted in second-trimester miscarriage, and 5 of the 11 pregnancies (45â¯%) developed preeclampsia, which resulted in preterm delivery, and 3 of the 12 pregnancies (25â¯%) achieved term delivery. The incidence of preeclampsia and preterm delivery was higher in those who experienced pain than in those without (45â¯% [5/11] vs. 15â¯% [11/74]; p<0.05, and 73â¯% [8/11] vs. 34â¯% [25/74]; p<0.05, respectively). Among women with pain, the maximum C-reactive protein level was significantly higher in women who developed preeclampsia than in those who did not (5.45 vs. 0.12â¯mg/dL, p<0.05). CONCLUSIONS: Our study revealed that adenomyosis can cause pain in over one of eight pregnancies with adenomyosis, which may be associated with the increased incidence of preeclampsia resulting in preterm delivery. Women with pain, especially those with high C-reactive protein levels, may be at high risk for future development of preeclampsia and consequent preterm delivery.
Assuntos
Aborto Espontâneo , Adenomiose , Pré-Eclâmpsia , Nascimento Prematuro , Humanos , Recém-Nascido , Gravidez , Feminino , Adenomiose/complicações , Adenomiose/epidemiologia , Adenomiose/patologia , Estudos Retrospectivos , Nascimento Prematuro/epidemiologia , Nascimento Prematuro/etiologia , Pré-Eclâmpsia/epidemiologia , Proteína C-Reativa , Aborto Espontâneo/epidemiologia , Aborto Espontâneo/etiologia , Dor/complicaçõesRESUMO
(Scanning) transmission electron microscopy (TEM) images of samples in gas and liquid media are acquired with an environmental cell (EC) via silicon nitride membranes. The ratio of sample signal against the background is a significant factor for resolution. Depth-sectioning scanning TEM (STEM) is a promising technique that enhances the signal for a sample embedded in a matrix. It can increase the resolution to the atomic level, thereby enabling EC-STEM applications in important areas. This review introduces depth-sectioning STEM and its applications to high-resolution EC-STEM imaging of samples in gases and in liquids.
RESUMO
Physical property prediction and synthesis process optimization are key targets in material informatics. In this study, we propose a machine learning approach that utilizes ridge regression to predict the oxygen permeability at fuel cell electrode surfaces and determine the optimal process temperature. These predictions are based on a persistence diagram derived from tomographic images captured using transmission electron microscopy (TEM). Through machine learning analysis of the complex structures present in the Pt/CeO2 nanocomposites, we discovered that l2 regularization considering diverse structural elements is more appropriate than l1 regularization (sparse modeling). Notably, our model successfully captured the activation energy of oxygen permeability, a phenomenon that could not be solely explained by the geometric feature of the Betti numbers, as demonstrated in a previous study. The correspondence between the ridge regression coefficient and persistence diagram revealed the formation process of the local and three-dimensional structures of CeO2 and their contributions to pre-exponential factor and activation energies. This analysis facilitated the determination of the annealing temperature required to achieve the optimal structure and accurately predict the physical properties.
RESUMO
BACKGROUND: The activity level of alkaline phosphatase, a zinc-requiring enzyme in the serum, is used to indicate zinc nutritional status; however, it does not correlate with serum zinc levels or subjective symptoms of taste disorder in many cases. Hence, this study focused on the total activity of alkaline phosphatase, a zinc-requiring enzyme. The total alkaline phosphatasa activity level in the saliva was measured before and after zinc supplementation, and the results were compared with serum zinc levels. CASE PRESENTATION: This study included patients with hypozincemia, specifically a patient with zinc-deficient taste disorder (patient 1: a 69-year-old Japanese woman) and a patient with glossodynia with zinc deficiency (patient 2: an 82-year-old Japanese woman). Saliva samples were collected, and blood tests were performed before and after zinc supplementation. Subjective symptoms and serum zinc levels were simultaneously evaluated. Zinc supplementation was performed using zinc acetate hydrate or Polaprezinc. CONCLUSIONS: Total alkaline phosphatase activity levels were found to be associated with serum zinc levels and subjective symptoms. A further study with a higher number of patients is necessary to confirm whether total alkaline phosphatase activity levels more accurately reflect the amounts of zinc in the body than serum zinc levels.
Assuntos
Fosfatase Alcalina , Zinco , Feminino , Humanos , Idoso , Idoso de 80 Anos ou mais , Saliva/metabolismo , Distúrbios do Paladar/diagnóstico , Acetato de ZincoRESUMO
OBJECTIVES: Zinc is crucial in the pathogenesis of hepatocellular carcinoma; however, no reports have examined its association with clinical parameters and zinc transporter 1 (ZNT1) expression intensity. This study aimed to assess the association between ZNT1 expression and prognosis in patients with hepatocellular carcinoma. METHODS: This retrospective study included 65 patients who underwent surgical hepatocellular carcinoma resection at a single center between January 2011 and June 2015. ZNT1 expression on hepatocellular carcinoma cells from specimens was assessed using immunohistochemistry, and the relationship between its intensity and various clinical indexes was examined with univariate and multivariable analyses and the Mann-Whitney U, Kruskal-Wallis, Bonferroni, and log-rank tests. RESULTS: ZNT1 expression on the hepatocellular carcinoma cell membrane was negative in 31 patients and positive in 34 patients, including nine patients showing strongly positive expression. Patients with and without ZNT1 expression had similar blood zinc concentrations, α-fetoprotein levels, protein induced by vitamin K absence-antagonist-II levels, gross classification, maximal tumor diameters, and background liver disease. The blood zinc concentrations were significantly lower in patients with strongly positive ZNT1 expression (57.0 ± 22.1 µg/dL) than in those with positive ZNT1 expression (71.1 ± 14.2 µg/dL; P = 0.015) or those with no ZNT1 expression (72.9 ± 14.1 µg/dL; P = 0.043). Overall survival was significantly shorter in ZNT1-expressing patients than in non-expressing patients (log-rank test, P = 0.024). Multivariable analysis using the Cox proportional hazards model identified maximal tumor diameter (hazard ratio, 1.018; 95% confidence interval, 1.002-1.034; P = 0.026) and ZNT1 expression status (hazard ratio, 2.082; 95% confidence interval, 1.196-3.621; P = 0.010) as prognostic contributing factors.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Estudos Retrospectivos , Zinco/metabolismoRESUMO
Carbon is a critical material for existing and emerging energy applications and there is considerable global effort in generating sustainable carbons. A particularly promising area is iron-catalyzed graphitization, which is the conversion of organic matter to graphitic carbon nanostructures by an iron catalyst. In this paper, it is reported that iron-catalyzed graphitization occurs via a new type of mechanism that is called homogeneous solid-state catalysis. Dark field in situ transmission electron microscopy is used to demonstrate that crystalline iron nanoparticles "burrow" through amorphous carbon to generate multiwalled graphitic nanotubes. The process is remarkably fast, particularly given the solid phase of the catalyst, and in situ synchrotron X-ray diffraction is used to demonstrate that graphitization is complete within a few minutes.