RESUMO
Thermoplastic polyurethane (TPU) doped with multi-walled carbon nanotubes (MWCNTs) at 1, 3, 5, and 7 wt% has been studied. The effect of MWCNTs on thermal, viscoelastic, and electric properties in the TPU matrix was characterized by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and by impedance spectroscopy. The results show that the thermal, electrical, and viscoelastic properties, such as the glass transition temperature, shifted towards high temperatures. The melting temperature decreased, and the conductivity and the storage modulus increased by 61.5 % and 58.3 %. The previously observed behavior on the films is due to the increase in the mass percentage of carbon nanotubes (CNTs) in the TPU matrix. Also, it can be said that the CNTs were homogeneously dispersed in the TPU matrix, preventing the movement of the polymer chains, and generating channels or connections that increase the conductivity and improve the thermal properties of the material.
RESUMO
Lethal bronzing (LB) is a fatal infection that affects over 20 species of palms (Arecaceae) and is caused by the phytoplasma 'Candidatus Phytoplasma aculeata'. This pathogen causes significant economic losses to landscape and nursery companies in Florida, USA. Recently, the vector was determined to be the planthopper Haplaxius crudus, which was more abundant on LB-infected palms. Herein, the volatile chemicals emitted from LB-infected palms were characterized using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS). Infected Sabal palmetto were identified and confirmed as positive for LB via quantitative PCR. Healthy controls of each species were selected for comparison. All infected palms exhibited elevated levels of hexanal and E-2-hexenal. Threatened palms showed high releasing concentrations of 3-hexenal and Z-3-hexen-1-ol. The volatiles characterized herein are common green-leaf volatiles (GLVs) emitted by plants under stress. This study considers the first documented case of GLVs in palms attributed to phytoplasma infection. Due to the apparent attraction of LB-infected palms to the vector, one or several of the GLVs identified in this study could serve as a lure for the vector and supplement management programs.
RESUMO
The impacts on the morphological, electrical and hardness properties of thermoplastic polyurethane (TPU) plates using multi-walled carbon nanotubes (MWCNTs) as reinforcing fillers have been investigated, using MWCNT loadings between 1 and 7 wt%. Plates of the TPU/MWCNT nanocomposites were fabricated by compression molding from extruded pellets. An X-ray diffraction analysis showed that the incorporation of MWCNTs into the TPU polymer matrix increases the ordered range of the soft and hard segments. SEM images revealed that the fabrication route used here helped to obtain TPU/MWCNT nanocomposites with a uniform dispersion of the nanotubes inside the TPU matrix and promoted the creation of a conductive network that favors the electronic conduction of the composite. The potential of the impedance spectroscopy technique has been used to determine that the TPU/MWCNT plates exhibited two conduction mechanisms, percolation and tunneling conduction of electrons, and their conductivity values increase as the MWCNT loading increases. Finally, although the fabrication route induced a hardness reduction with respect to the pure TPU, the addition of MWCNT increased the Shore A hardness behavior of the TPU plates.
RESUMO
ABSTRACT Background Reduced or null expression of E-cadherin protein is a frequent cause of diffuse gastric cancer (DGC). More than 50% of patients with DGC present somatic variants in CDH1 gene. Objectives The objectives of this study were to study E-cadherin expression and identify variants in the CDH1 gene in gastric tumors of patients with DGC. Methods We studied 18 Mexican DGC patients who attended a hospital of the Mexican Social Security Institute; E-cadherin expression was determined by immunohistochemistry, and variants were identified by Sanger sequencing in promoter and coding regions. Predictive analysis was performed using PolyPhen-2 and HOPE software. Results We found that 56% of DGC patients showed reduced expression of E-cadherin. All patients carried CDH1 variants; overall, 12 different CDH1 variants were identified. Predictive analysis revealed that the rs114265540 variant was probably damaging, with a value of 0.985, indicating a functional impact on the E-cadherin protein. Variants rs34939176 and rs33964119 were identified as risk factors for DGC (odds' ratios [OR] = 31.3, 95% CI 6.3-154.0, p < 0.001; OR = 6.1, 95% CI 2.0-19.0, p < 0.001, respectively) given their elevated frequency and by comparing it with those reported for MXL population in the 1000 Genomes Project database. Conclusions In this Mexican population, the percentage of diffuse gastric tumors with reduced expression of E-cadherin was similar to that reported in other populations. All gastric tumors of DGC patients studied had somatic CDH1 gene variants; however, the rs114265540, rs34939176, and rs33964119 variants were importantly related to DGC.
RESUMO
Background: Reduced or null expression of E-cadherin protein is a frequent cause of diffuse gastric cancer (DGC). More than 50% of patients with DGC present somatic variants in CDH1 gene. Objectives: The objectives of this study were to study E-cadherin expression and identify variants in the CDH1 gene in gastric tumors of patients with DGC. Methods: We studied 18 Mexican DGC patients who attended a hospital of the Mexican Social Security Institute; E-cadherin expression was determined by immunohistochemistry, and variants were identified by Sanger sequencing in promoter and coding regions. Predictive analysis was performed using PolyPhen-2 and HOPE software. Results: We found that 56% of DGC patients showed reduced expression of E-cadherin. All patients carried CDH1 variants; overall, 12 different CDH1 variants were identified. Predictive analysis revealed that the rs114265540 variant was probably damaging, with a value of 0.985, indicating a functional impact on the E-cadherin protein. Variants rs34939176 and rs33964119 were identified as risk factors for DGC (odds' ratios [OR] = 31.3, 95% CI 6.3-154.0, p < 0.001; OR = 6.1, 95% CI 2.0-19.0, p < 0.001, respectively) given their elevated frequency and by comparing it with those reported for MXL population in the 1000 Genomes Project database. Conclusions: In this Mexican population, the percentage of diffuse gastric tumors with reduced expression of E-cadherin was similar to that reported in other populations. All gastric tumors of DGC patients studied had somatic CDH1 gene variants; however, the rs114265540, rs34939176, and rs33964119 variants were importantly related to DGC.
Assuntos
Neoplasias Gástricas , Humanos , Antígenos CD/genética , Caderinas/genética , Predisposição Genética para Doença , México , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologiaRESUMO
BACKGROUND/AIM: During pregnancy, maternal liver can be affected by ethanol (ETOH) intake, whose effects depend on concentration levels ingested. This study aims to describe histological and serum marker characteristics of maternal liver during two metabolic conditions: gestation (G), and sustained ETOH intake, in early and late pregnancy. MATERIALS AND METHODS: Wistar rats were fed with Lieber-DeCarli diet during pregnancy, following an experimental protocol that allows a semi-chronic intake of ETOH (5%). Liver and serum samples were processed for histological characterization and biochemical profiling. Hematoxylin/eosin and Schiff's Periodic Acid staining were used. RESULTS: During pregnancy, a significant elevation in ballooned and edamatous hepatocytes, and a significant increase in micro and macrovesicular deposits were observed in rats fed with the ETOH diet at gestation days 3G, 8G and 15G. These changes were reverted by 20G. Liver glycogen content increased significantly at 15G. Serum metabolites in pregnant rats fed with the ETOH diet showed a significant reduction in urea (from 3G to 15G), an increase in albumin and uric acid at 20G, and a reduction in creatinine. Number of offsprings and weight of male newborns were reduced by 20% and 14%, respectively. Liver function markers in serum showed no significant changes. CONCLUSION: ETOH diet intake promotes hepatic histological changes and histological modifications during pregnancy. These results support the assumption that pregnancy is an adaptive procedure that is associated with nutritional conditions and has a strong influence on hepatic histology. They suggest that pregnancy promotes a state of resilience to the liver function during the sustained intake of 5% ETOH.
Assuntos
Dieta , Fígado , Animais , Etanol , Feminino , Hepatócitos , Fígado/patologia , Masculino , Gravidez , Ratos , Ratos WistarRESUMO
Breast cancer (BC) diagnosis is made by a pathologist who analyzes a portion of the breast tissue under the microscope and performs a histological evaluation. This evaluation aims to determine the grade of cellular differentiation and the aggressiveness of the tumor by the Nottingham Grade Classification System (NGS). Nowadays, digital pathology is an innovative tool for pathologists in diagnosis and acquiring new learning. However, a recurring problem in health services is the excessive workload in all medical services. For this reason, it is required to develop computational tools that assist histological evaluation. This work proposes a methodology for the quantitative analysis of BC tissue that follows NGS. The proposed methodology is based on digital image processing techniques through which the BC tissue can be characterized automatically. Moreover, the proposed nuclei characterization was helpful for grade differentiation in carcinoma images of the BC tissue reaching an 0.84 accuracy. In addition, a metric was proposed to assess the likelihood of a structure in the tissue corresponding to a tubule by considering spatial and geometrical characteristics between lumina and its surrounding nuclei, reaching an accuracy of 0.83. Tests were performed from different databases and under various magnification and staining contrast conditions, showing that the methodology is reliable for histological breast tissue analysis.
Assuntos
Neoplasias da Mama , Neoplasias da Mama/diagnóstico , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Microscopia , Coloração e RotulagemRESUMO
Introduction Different factors are critical when assessing COVID-19 mortality, and can explain why severity differs so widely among populations. However, there is little information regarding prognostic factors and mortality in COVID-19 from Latin American countries. Objectives To determine prognostic factors in hospitalized COVID-19 patients and to evaluate the impact of tocilizumab use in patients with hyperinflammatory syndrome and severe disease defined by the National Early Warning Score 2 (NEWS2) with a value greater than or equal to seven points. Materials and methods This retrospective cohort study included hospitalized COVID-19 patients from May to July 2020. A multivariate logistic regression analysis was performed to determine independent factors associated with mortality. Results A total of 136 patients required hospital admission. In-hospital mortality was 39.7%. Mortality was observed to be potentiated by older age, LDH serum levels and the presence of type 2 diabetes mellitus. Lymphopenia and lower PaO2/FiO2 ratio were more common in these patients. Similarly, patients who died were classified more frequently with severe disease. The independent factors associated with in-hospital mortality were age greater than 65 years, type 2 diabetes mellitus, NEWS2 greater than or equal to seven points and LDH greater than 400U/L. The use of Tocilizumab alone was not related with decreased in-hospital mortality. Subgroup analysis performed in patients with hyperinflammation and severe disease showed similar results. Conclusions COVID-19 mortality in hospitalized patients was high and mainly related with older age, comorbidities, LDH and the severity of disease at hospital admission.
RESUMO
Females of many vertebrate species are territorial. However, few studies have been performed on territorial aggression and its hormonal bases in females. The present study determined whether dwarf hamster females (Phodopus campbelli) display territorial aggression and the role that estradiol (E2 ) and progesterone (P4 ) play in this behavior. Two experiments were carried out. First, 28 virgin females were mated with sexually inexperienced males. The females were submitted to oviduct ligation 2 weeks before mating to prevent pregnancy. After 15 days of mating, 16 out of 28 females were submitted to resident-intruder tests, whereas the remaining 12 females were nonconfronted. Blood samples were collected 30 min after the aggression tests to determine E2 and P4 by ELISA. In the second experiment, 40 females were mated with vasectomized males. Thirty days after mating, 30 dwarf hamsters were subjected to ovariectomy; 10 were nontreated, 10 were treated with E2 , and 10 with P4 . The remaining 10 were sham-operated. All females were submitted to resident-intruder tests, and blood samples were taken to quantify E2 and P4 . In the first experiment, 87.5% of dwarf hamster females displayed territorial aggression, and in the second, 100% of females were aggressive. Ovariectomy and ovariectomy plus E2 or P4 replacement did not affect aggressive territorial behavior. These results showed that this species' females are territorial, and this behavior is not dependent on ovarian steroid hormones.
Assuntos
Agressão , Phodopus , Animais , Cricetinae , Estradiol , Feminino , Humanos , Masculino , Gravidez , ProgesteronaRESUMO
INTRODUCTION AND AIM: Intake of a high-carbohydrate, low-protein diet (HCD/LPD) during pregnancy promotes metabolic disturbances. It has been suggested that liver function during pregnancy contributes to the synthesis of proteins necessary for fetal development during this stage. The liver is a site of response to the synthesis of macronutrients such as proteins. However, it is unknown how HCD/LPD is associated with modifications to the amino acid profiles and hepatic alterations in the maternal environment during pregnancy. MATERIALS AND METHODS: A transverse longitudinal study was done in primiparous mothers during gestation (G) (G1 day 1, G5 day 5, G15 day 15, and G20 day 20). Histological analysis was used to assess hepatic alterations, and amino acid profiles in the liver were analyzed with high performance liquid chromatography (HPLC). Food and water intake was quantified, and peripheral biochemical indicators in serum were measured. RESULTS: Mothers with HCD/LPD had increased micro and macro vesicles of fat, necrosis, and inflammation in the liver on G5. The total concentration of hepatic amino acids increased by 40% on G1, 17% on G5, and 25% on G15; and, there was a 12% decrease on G20. The following increases were observed in the liver on G1: arginine 68%, histidine 75%, alanine 18%, methionine 71%, and phenylalanine 51% (p>0.05); on G5: arginine 12%, methionine 34%, and phenylalanine 83% (p>0.05); on G15: arginine and phenylalanine 66%, tryptophan 81% and histidine 60.4% (p>0.05); and on G20: arginine 32% (p>0.05). No weight loss, changes in food consumption, or hepatomegaly occurred. CONCLUSIONS: HCD/LPD during pregnancy in primiparous mothers may promote development of fat vesicles. Possibly, this condition causes metabolic adaptations and nitrogen management reflected in decreased levels of serum urea and altered amino acid profiles in the liver.