974 resultados para network effect
Resumo:
In this work we report the adsorption of phenylalanine (Phe) on Magnesium Aluminum Layered Double Hydroxides (Mg-Al-CO(3)-LDH) at two different temperatures (298 and 310 K) and under two distinct ionic strength conditions (with and without the addition 0.1 M of NaCl). The adsorption isotherms exhibit the same profile in all conditions, and they only differ in the amount of removed Phe. At lower ionic strength, the isotherms are almost identical at both temperatures, except for the last points, where the increase in temperature causes a decrease in the amount of adsorbed Phe. An increase in ionic strength results in a decrease in Phe adsorption. The electrokinetic potential decreases as the amount of adsorbed Phe increases, and only positive values are observed. This indicates that the surface of the adsorbent is not totally neutralized and suggests that more Phe could be removed by adsorption. The presence of Phe on the solid is confirmed by FTIR spectra, which present the specific bands assigned to Phe. The hydrophobicity of the amino acid probably contributes to its extraction, thus enabling the removal of a great amount of Phe. In conclusion, LDH is potentially applicable in the removal of Phe from wastewater.
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This study reports on the development and characterization of bovine serum albumin (BSA) nanospheres containing Silicon(IV) phthalocyanine (NzPc) and/or maghemite nanoparticles (MNP), the latter introduced via ionic magnetic fluid (MF). The nanosized BSA-loaded samples were designed for synergic application while combining Photodynamic Therapy and Hyperthermia. Incorporation of MNP in the albumin-based template, allowing full control of the magnetic content, was accomplished by adding a highly-stable ionic magnetic fluid sample to the albumin suspension, following heat denaturing. The material`s evaluation was performed using Zeta potential measurements and scanning electron microscopy. The samples were characterized by steady-state techniques and time-resolved fluorescence. The in vitro assay, using human fibroblasts, revealed no cytotoxic effect in all samples investigated, demonstrating the potential of the tested system as a synergistic drug delivery system.
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Through the study of the action of the inquisition commissioners, this article seeks to reveal the relations between the Portuguese Inquisition and the ecclesiastical structure of the Minas Gerais State Captaincy in the colonial period. The focus of the analysis will be the making and the action of the network of Holy Inquisition commissioners in the gold Captaincy. What was the profile of these commissioners? How were they recruited from the local ecclesiastical hierarchy? What was the role assigned to them in the inquisitional action that took place in Minas Gerais? How did they act? What was the relationship between the introduction of the commissioners into the local ecclesiastical structures and the commissioners` inquisitorial activities?
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The combined approach of the molecular-kinetic and hydrodynamic theories for description of the motion of three-phase gas-liquid-solid contact lines has been examined using the Wilhelmy plate method. The whole dynamic meniscus has been divided into molecular, hydrodynamic, and static-like regions. The Young-Laplace equation and the molecular-kinetic and hydrodynamic dewetting theories have been applied to describe the meniscus profiles and contact angle. The dissipative forces accompanying the dynamic dewetting have also been investigated. The experiments with a Wilhelmy plate made from an acrylic polymer sheet were carried out using a computerized apparatus for contact angle analysis (OCA 20, DataPhysics, Germany). The extrapolated dynamic contact angle versus velocity of the three-phase contact line for Milli-Q water and 5 x 10(-4) M SDBS solution was experimentally obtained and compared with the combined MHD models with low and moderate Reynolds numbers. The models predict similar results for the extrapolated contact angle. SDBS decreases the equilibrium contact angle and increases the molecular jumping length but does not affect the molecular frequency significantly. The hydrodynamic deformation of the meniscus, viscous dissipation, and friction were also influenced by the SDBS surfactant. (c) 2005 Elsevier Inc. All rights reserved.
Resumo:
Hepatocyte proliferation and apoptosis (programmed cell death) occur during the liver parenchyma regeneration and the liver size modeling is mainly controlled by hepatocyte apoptosis. The purpose of the present study was to verify the influence of immunosuppressant drugs on these phenomena by utilizing tissue microarray techniques. Thirty-six weaning rats (age 21-23 days, weight 30-50 g) were divided into six groups: control, sham, hepatectomy, hepatectomy plus solumedrol, hepatectomy plus CsA, and hepatectomy plus Tac. The animals were killed one day after hepatectomy, and the remnant livers were weighed and harvested for tissue microarray sections. Liver cell proliferation was evaluated by staining for PCNA and apoptosis was detected by the TUNEL method. It was verified that CsA promoted a decrease in the liver weight, Tac and CsA decreased the proliferation index of hepatocytes, and glucocorticoid had no significant effects. The apoptosis index was not altered by hepatectomy or immunosuppressants. Our data indicate that, in the growing rat, CsA and Tac have negative effects on hepatocyte proliferation and have no effect on the hepatocyte apoptosis.
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Mental rotation involves the creation and manipulation of internal images, with the later being particularly useful cognitive capacities when applied to high-level mathematical thinking and reasoning. Many neuroimaging studies have demonstrated mental rotation to be mediated primarily by the parietal lobes, particularly on the right side. Here, we use fMRI to show for the first time that when performing 3-dimensional mental rotations, mathematically gifted male adolescents engage a qualitatively different brain network than those of average math ability, one that involves bilateral activation of the parietal lobes and frontal cortex, along with heightened activation of the anterior cingulate. Reliance on the processing characteristics of this uniquely bilateral system and the interplay of these anterior/posterior regions may be contributors to their mathematical precocity.
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Background: The objective of this study was to evaluate the effects of a contraceptive pill containing ethinylestradiol (30 mcg) and drospirenone (3 mg) in a continuous regimen on lipid, carbohydrate and coagulation parameters. Study Design: This open, prospective, randomized study included 78 participants (mean age 27.8 years) who were randomized into two groups to use the pill continuously for 168 days or for six 28-day cycles with a 7-day hormone-free interval between cycles. Markers of lipid, carbohydrate and coagulation profiles were measured prior to initiation and after the 6 months of pill use. Results: No statistically significant differences were found between the two contraceptive regimens with respect to carbohydrate or lipid profiles or in the parameters related to coagulation. Conclusions: The contraceptive combination of ethinylestradiol and drospirenone used in a continuous regimen was associated with metabolic alterations similar to those found during the traditional cyclic regimen of oral contraceptive use. (C) 2010 Elsevier Inc. All rights reserved.
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Individuals with Autism Spectrum Disorder (ASD) are generally thought to have impaired attentional and executive function upon which all their cognitive and behaviour functions are based. Mental Rotation is a recognized visuo-spatial task, involving spatial working memory, known to involve activation in the fronto-parietal networks. To elucidate the functioning of fronto-parietal networks in ASD, the aim of this study was to use fMRI techniques with a mental rotation task, to characterize the underlying functional neural system. Sixteen male participants (seven highfunctioning autism or Asperger's syndrome; nine ageand performance IQ-matched controls) underwent fMRI. Participants were presented with 18 baseline and 18 rotation trials, with stimuli rotated 3- dimensionaUy (45°-180°). Data were acquired on a 3- Tesla scanner. The most widely accepted area reported to be involved in processing of visuo-spatial information. Posterior Parietal Cortex, was found to be activated in both groups, however, the ASD group showed decreased activation in cortical and subcortical frontal structures that are highly interconnected, including lateral and medial Brodmann area 6, frontal eye fields, caudate, dorsolateral prefrontal cortex and anterior cingulate. The suggested connectivity between these regions indicates that one or more circuits are impaired as a result of the disorder. In future it is hoped that we are able to identify the possible point of origin of this dysfunction, or indeed if the entire network is dysfunctional.
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It has been suggested that phosphate binders may reduce the inflammatory state of hemodialysis (HD) patients. However, it is not clear whether it has any effect on oxidative stress. The objective of this study was to evaluate the effect of sevelamer hydrochloride (SH) and calcium acetate (CA) on oxidative stress and inflammation markers in HD patients. Hemodialysis patients were randomly assigned to therapy with SH (n=17) or CA (n=14) for 1 year. Before the initiation of therapy (baseline) and at 12 months, we measured in vitro reactive oxygen species (ROS) production by stimulated and unstimulated polymorphonuclear neutrophils and serum levels of tumor necrosis factor alpha, interleukin-10, C-reactive protein, and albumin. There was a significant reduction of spontaneous ROS production in both groups after 12 months of therapy. There was a significant decrease of Staphylococcus aureus stimulated ROS production in the SH group. There was a significant increase in albumin serum levels only in the SH group. In the SH group, there was also a decrease in the serum levels of tumor necrosis factor alpha and C-reactive protein. Our results suggest that compared with CA treatment, SH may lead to a reduction in oxidative stress and inflammation. Therefore, it is possible that phosphate binders exert pleiotropic effects on oxidative stress and inflammation, which could contribute toward decreasing endothelial injury in patients in HD.
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Objective. To develop a questionnaire for the evaluation of sexuality of male patients with juvenile idiopathic arthritis (JIA). Methods. A cohort of male patients with rheumatoid factor (RF)-negative polyarticular. JIA according to the 2004 revised ILAR criteria and inactive disease was Studied. The Health Assessment Questionnaire (HAQ) was applied to all patients. As a control group, 120 age-matched males of the same socioeconomic status were evaluated. A self-administered Structured instrument, the Male Sexual Evaluation Questionnaire (MSEQ), was developed by multiprofessional experts to assess sexual life, including satisfaction, practice. and related functional aspects. Results. Thirty-two male patients with RF-negative polyarticular JIA [mean age 20.8 +/- 3.8 yrs (range 16-26), mean disease duration 15.4 +/- 3.6 yrs (range 13-20)] were studied. Mean HAQ score was 1.25 +/- 0.67 (range 0.1-2.1). Masturbation was practiced similarly by patients and controls (87.5% vs 91%; p > 0.999), although joint pain was observed in only 2 (7%) patients. Regular sexual intercourse (>= once/week) was reported by 78% of patients and 62% of controls (p = 0.86). Joint pain during intercourse was more frequent in patients (48% vs 3% in controls; p < 0.001). The mean HAQ score was higher in the 12 patients with,joint pain (hips = 3, knees = 5, and hips + knees = 4) during intercourse compared to the 13 patients without joint pain (1.82 +/- 0.27 vs 1.43 +/- 0.32; p < 0.05). Preserved desire and satisfaction were universal findings for all JIA patients and controls. Conclusion. The MSEQ was applicable to this cohort of male patients with RF-negative polyarticular JIA and showed that sexual life is preserved despite longterm disease, morbidity/functional dysfunction, and joint pain. (First Release May 1 2009: J Rheumatol 2009;36: 1337-42; doi: 10.3899/jrheum.080867)
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The specific role of the hypothalamus in regulating the developmental profile of anterior pituitary (AP) cells remains largely unknown. The present study evaluated hypothalamic contributions to AP cell development, utilizing the technique of hypothalamo-pituitary disconnection (HPD). HPD of fetal sheep or sham surgery was performed at 110 days gestation (d) (n=6 each group; term ~ 147d). Fetuses were removed and pituitaries collected at 110d (no surgery; n=6) or 141d (sham and HPD groups). The impact of HPD on AP cell development was assessed by single-labeled immunofluorescence for five hormones to identify proportions of AP cells expressing each hormone. HPD was associated with a 70% increase (P
Resumo:
Context: 21-Hydroxylase deficiency (21OHD) is caused by CYP21A2 gene mutations disrupting the adrenal 21-hydroxylase, P450c21. CYP21A2 mutations generally correlate well with the 21OHD phenotype, but some children with severe CYP21A2 mutations have residual 21-hydroxylase activity. Some hepatic P450 enzymes can 21-hydroxylate progesterone, but their physiological relevance in modifying 21OHD is not known. Objective: Wedetermined the ability of CYP2C19 and CYP3A4 to 21-hydroxylate progesterone and 17-hydroxyprogesterone (17OHP), determined the impact of the common P450 oxidoreductase (POR) variant A503V on these activities, and examined correlations between CYP2C19 variants and phenotype in patients with 21OHD. Methods: Bacterially expressed, N-terminally modified, C-His-tagged human P450c21, CYP2C19, and CYP3A4 were combined with bacterially expressed wild-type and A503V POR. The 21-hydroxylation of radiolabeled progesterone and 17OHP was assessed, and the Michaelis constant (Km) and maximum velocity (Vmax) of the reactions were measured. CYP2C19 was genotyped in 21OHD patients with genotypes predicting severe congenital adrenal hyperplasia. Results: Compared to P450c21, the Vmax/Km for 21-hydroxylation of progesterone by CYP2C19 and CYP3A4 were 17 and 10%, respectively. With both forms of POR, the Km for P450c21 was approximately 2.6 mu M, the Km for CYP2C19 was approximately 11 mu M, and the Km for CYP3A4 was approximately 110 mu M. Neither CYP2C19 nor CYP3A4 could 21-hydroxylate 17OHP. The CYP2C19 ultrametabolizer allele CYP2C19* 17 was homozygous in one of five patients with a 21OHD phenotype that was milder than predicted by the CYP21A2 genotype. Conclusions: CYP2C19 and CYP3A4 can 21-hydroxylate progesterone but not 17OHP, possibly ameliorating mineralocorticoid deficiency, but not glucocorticoid deficiency. Multiple enzymes probably contribute to extraadrenal 21-hydroxylation. (J Clin Endocrinol Metab 94: 89-95, 2009)