The soils of Brazilian Cerrado are characterized with high acidity and low fertility and productivity.However,these attributes are not homogeneously distributed through all phytophysiognomies of this biome,and wetland...The soils of Brazilian Cerrado are characterized with high acidity and low fertility and productivity.However,these attributes are not homogeneously distributed through all phytophysiognomies of this biome,and wetland known as palm swamp or“veredas”are an exception.This study aimed to describe and compare the chemical and physical attributes of soil surface layers at six palm swamps areas under different anthropization processes in the northern region of Minas Gerais state,Brazil.Soil sampling of different hydromorphic soils were collected at 0-20 cm depth layer from 100 m2 plots in the studied areas.The variables were compared using the GLM procedure of ANOVA using Statistica 10 software.Soil chemical attributes and similarities between the six palm swamps areas were compared using the statistical software R.Soil chemical attributes were different and soil physical attributes were similar between the evaluated areas.The similarities among the attributes were classified into three groups according to the anthropic pressures,as well as with the origin of the soil material in the six palm swamps areas evaluated.It could be concluded that soil fertility can be reduced in palm swamps that suffered greater anthropic intervention.The three similarity groups might be associated not only to the anthropic pressures,but also to the raw material of soil at the six palm swamps areas evaluated.展开更多
The objective of this study was to evaluate the chemical and physical attributes of soil, and the productivity of Eucalyptus cultivated in monoculture and silvopastoral systems. The experiment started in 2009 and eval...The objective of this study was to evaluate the chemical and physical attributes of soil, and the productivity of Eucalyptus cultivated in monoculture and silvopastoral systems. The experiment started in 2009 and evaluated the following four systems: native vegetation system (Cerrado), a degraded pasture, a Eucalyptus urograndis monoculture (E. urophylla x E. grandis) and a silvopastoral system (E. urograndis combined with Brachiaria brizantha cv. "Marandu"). The experimental design used was completely randomized. In each system, four soil samples were collected from the 0-20 cm depth layer, and the chemical and physical attributes of the soil were evaluated. The diameters of all Eucalyptus trees at 1.30 m above the ground as well as the total height were measured. Subsequently, the trees dimensions were measured and their individual volumes obtained by applying the Smalian formula. The correlation between the parameters for Eucalyptus production and soil attributes was established using the Pearson's correlation coefficient method. The planting of Eucalyptus in monoculture and silvopastoral systems contributed to the improvement of the soil's chemical and physical attributes, which indicates the potential of these systems for recovery of degraded pastures. The silvopastoral system yielded the highest average volume of wood per tree (0.2228 m^3), with a productivity of 111.4 m^3/ha. The Eucalyptus monoculture yielded 0.1895 m^3 per tree and 315.71 m^3/ha due to the higher density of the crop. The growth and productivity of Eucalyptus showed highly correlation with the soil attributes, thus suggesting that well-managed crops are an indicator of the soil quality recovery.展开更多
Curimat?-pioa (Prochilodus costatus) and curimat?-pacu (Prochilodus argenteus) are migratory fish species endemic to the S?o Francisco River Basin in Brazil. Both species play important roles in local fisheries and ec...Curimat?-pioa (Prochilodus costatus) and curimat?-pacu (Prochilodus argenteus) are migratory fish species endemic to the S?o Francisco River Basin in Brazil. Both species play important roles in local fisheries and ecology in the Paraopeba River. A dam was recently constructed on this river and to help in the development and conservation programs, we characterized the genetic variation of both species before dam construction. Complex hypervariable repeats micro-satellite was used to asses genetic variation for both species within and between the five collection sites in order to detect population substructuring. Nucleotide substitutions and insertion/deletion polymorphisms (indels) resulted in 35 P. costatus haplotypes (sample size = 89) and 22 P. argenteus haplotypes (sample size = 32). Significant genetic diversity and population differentiation was detected between five sampling sites for both species. Therefore, each of the five sites should be regarded as a group comprising significant genetic differences in species conservation and maintenance plans. Comparing these results to genetic diversity measures after dam construction will be critical for future management in this region.展开更多
The Zika virus(ZIKV),a member of the Flaviviridae family,attracted worldwide attention for its connection to severe neurological effects,notably microcephaly in newborns,first reported during the 2015 epidemic in Braz...The Zika virus(ZIKV),a member of the Flaviviridae family,attracted worldwide attention for its connection to severe neurological effects,notably microcephaly in newborns,first reported during the 2015 epidemic in Brazil.Yet,its impact goes beyond fetal and neonatal abnormalities,also affecting the central nervous system(CNS)in both children and adults,leading to enduring cognitive and behavioral impairments.展开更多
Stem cell therapy is a promising approach to clinical healing in several diseases. A great variety of tissues(bone marrow, adipose tissue, and placenta) arepotentially sources of stem cells. Placenta-derived stem cell...Stem cell therapy is a promising approach to clinical healing in several diseases. A great variety of tissues(bone marrow, adipose tissue, and placenta) arepotentially sources of stem cells. Placenta-derived stem cells(p-SCs) are in between embryonic and mesenchymal stem cells, sharing characteristics with both, such as non-carcinogenic status and property to differentiate in all embryonic germ layers. Moreover, their use is not ethically restricted as fetal membranes are considered medical waste after birth. In this context, the present review will be focused on the biological properties, culture and potential cell therapy uses of placental-derived stem cells. Immunophenotype characterization, mainly for surface marker expression, and basic principles of p-SC isolation and culture(mechanical separation or enzymatic digestion of the tissues, the most used culture media, cell plating conditions) will be presented. In addition, some preclinical studies that were performed in different medical areas will be cited, focusing on neurological, liver, pancreatic, heart, muscle, pulmonary, and bone diseases and also in tissue engineering field. Finally, some challenges for stem cell therapy applications will be highlighted. The understanding of the mechanisms involved in the p-SCs differentiation and the achievement of pure cell populations(after differentiation) are key points that must be clarified before bringing the preclinical studies, performed at the bench, to the medical practice.展开更多
To evaluate the therapeutic effects of bone marrow-derived CD11b<sup>+</sup>CD14<sup>+</sup> monocytes in a murine model of chronic liver damage.METHODSChronic liver damage was induced in C57BL...To evaluate the therapeutic effects of bone marrow-derived CD11b<sup>+</sup>CD14<sup>+</sup> monocytes in a murine model of chronic liver damage.METHODSChronic liver damage was induced in C57BL/6 mice by administration of carbon tetrachloride and ethanol for 6 mo. Bone marrow-derived monocytes isolated by immunomagnetic separation were used for therapy. The cell transplantation effects were evaluated by morphometry, biochemical assessment, immunohistochemistry and enzyme-linked immunosorbent assay.RESULTSCD11b<sup>+</sup>CD14<sup>+</sup> monocyte therapy significantly reduced liver fibrosis and increased hepatic glutathione levels. Levels of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-6 and IL-1β, in addition to pro-fibrotic factors, such as IL-13, transforming growth factor-β1 and tissue inhibitor of metalloproteinase-1 also decreased, while IL-10 and matrix metalloproteinase-9 increased in the monocyte-treated group. CD11b<sup>+</sup>CD14<sup>+</sup> monocyte transplantation caused significant changes in the hepatic expression of α-smooth muscle actin and osteopontin.CONCLUSIONMonocyte therapy is capable of bringing about improvement of liver fibrosis by reducing oxidative stress and inflammation, as well as increasing anti-fibrogenic factors.展开更多
Parkinson’s disease is the most common movement disorder,affecting about 1%of the population over the age of 60 years.Parkinson’s disease is characterized clinically by resting tremor,bradykinesia,rigidity and postu...Parkinson’s disease is the most common movement disorder,affecting about 1%of the population over the age of 60 years.Parkinson’s disease is characterized clinically by resting tremor,bradykinesia,rigidity and postural instability,as a result of the progressive loss of nigrostriatal dopaminergic neurons.In addition to this neuronal cell loss,Parkinson’s disease is characterized by the accumulation of intracellular protein aggregates,Lewy bodies and Lewy neurites,composed primarily of the proteinα-synuclein.Although it was first described almost 200 years ago,there are no disease-modifying drugs to treat patients with Parkinson’s disease.In addition to conventional therapies,non-pharmacological treatment strategies are under investigation in patients and animal models of neurodegenerative disorders.Among such strategies,environmental enrichment,comprising physical exercise,cognitive stimulus,and social interactions,has been assessed in preclinical models of Parkinson’s disease.Environmental enrichment can cause structural and functional changes in the brain and promote neurogenesis and dendritic growth by modifying gene expression,enhancing the expression of neurotrophic factors and modulating neurotransmission.In this review article,we focus on the current knowledge about the molecular mechanisms underlying environmental enrichment neuroprotection in Parkinson’s disease,highlighting its influence on the dopaminergic,cholinergic,glutamatergic and GABAergic systems,as well as the involvement of neurotrophic factors.We describe experimental pre-clinical data showing how environmental enrichment can act as a modulator in a neurochemical and behavioral context in different animal models of Parkinson’s disease,highlighting the potential of environmental enrichment as an additional strategy in the management and prevention of this complex disease.展开更多
The discovery of the Gouap banded iron formations(BIFs)-hosted iron mineralization in the northwestern of the Nyong Group(Ntem Complex)in southwestern Cameroon provides unique insights into the geology of this region....The discovery of the Gouap banded iron formations(BIFs)-hosted iron mineralization in the northwestern of the Nyong Group(Ntem Complex)in southwestern Cameroon provides unique insights into the geology of this region.In this contribution,we firstly report detailed study of geochemistry,isotopic and geochronology of well preserved samples of the Gouap BIFs collected from diamond drillcores.The Gouap BIFs consist mainly of amphibole BIFs and amphibole-pyrite BIFs characterized by dominant Fe_(2)O_(3)+SiO_(2)contents and variable contents of CaO,MgO and SO_(3),consistent with the presence of amphibole,chlorite,epidote and pyrite,formed during amphibolite facies metamorphism and overprinted hydrothermal event.The amphibole–pyrite BIFs are typically enriched in trace and rare earth elements(REE)compared to the amphibole BIFs,suggesting the influence of detrital materials as well as secondary hydrothermal alteration.The Post Archean Australian Shale(PAAS)-normalized REE–Y profiles of the Gouap BIFs display positive La,Eu anomalies,weak negative Ce anomalies,indicating a mixture of low-temperature hydrothermal fluids and relatively oxic conditions probably under relative shallow seawater.We present here the first isotopic data of BIFs within the Ntem Complex.Theδ^(30)Si_(NBS28)values of the quartz from the Gouap BIFs vary from-1.5‰to-0.3‰and from-0.8‰to-0.9‰for the amphibole BIFs and amphibole–pyrite BIFs,respectively.The quartz hasδ^(18)OV-SMOW values of 6.8‰–9.5‰(amphibole BIFs)and 9.2‰–10.6‰(amphibole–pyrite BIFs).The magnetite from the Gouap BIFs showsδ^(18)O values ranging from-3.5‰to-1.8‰and from-3‰to-1.7‰for the amphibole BIFs and amphibole–pyrite BIFs,respectively.Moreover,the pyrite grains in the amphibole–pyrite BIFs displayδ34S values of 1.1‰–1.8‰.All isotopic data of the Gouap BIFs confirm that they might have precipitated from low-temperature hydrothermal fluids with detrital input distant from the volcanic activity.According to their geochemical and isotopic characteristics,we propose that the Gouap BIFs belong to the Superior type.In situ U–Pb zircon dating of BIFs was conducted to assess the BIF depositional age based on strong evidence of zircon in thin section.The Gouap BIFs were probably deposited at 2422±50 Ma in a region where sediments extended from continental shelf to deep-water environments along craton margins like the Caue Formation of the Minas Supergroup,Brazil.The studied BIFs have experienced regional hydrothermal activity and metamorphism at 2089±8.3 Ma during the Eburnean–Transamazonian orogeny.These findings suggest a physical continuity between the protocratonic masses of both Sao Francisco and Congo continents in the Rhyacian Period.展开更多
Postpartum depression is one of the most prevalent psychopathologies. Its prevalence is estimated to be between 10% and 15%. Despite its multifactorial etiology, it is known that genetics play an important role in the...Postpartum depression is one of the most prevalent psychopathologies. Its prevalence is estimated to be between 10% and 15%. Despite its multifactorial etiology, it is known that genetics play an important role in the genesis of this disorder. This paper reviews epidemiological evidence supporting the role of genetics in postpartum depression(PPD). The main objectives of this review are to determine which genes and polymorphisms are associated with PPD and discuss how this association may occur. In addition, this paper explores whether these genes are somehow related to or even the same as those linked to Major Depression(MD). To identify gaps in the current knowledge that require investigation, a systematic review was conducted in the electronic databases Pub Med, LILACS and Sci ELO using the index terms "postpartum depression" and "genetics". Literature searches for articles in peerreviewed journals were made until April 2014. PPD was indexed 56 times with genetics. The inclusion criteria were articles in Portuguese, Spanish or English that were available by institutional means or sent by authors upon request; this search resulted in 20 papers. Genes and polymorphisms traditionally related to MD, which are those involved in the serotonin, catecholamine, brain-derived neurotrophic factor and tryptophan metabolism, have been the most studied, and some have been related to PPD. The results are conflicting and some depend on epigenetics, which makes the data incipient. Further studies are required to determine the genes that are involved in PPD and establish the nature of the relationship between these genes and PPD.展开更多
BACKGROUND Chronic hepatitis C(CHC)is associated with type 2 diabetes mellitus.Although the pathogenesis remains to be elucidated,a growing evidence has suggested a role of pro-inflammatory immune response.Increased s...BACKGROUND Chronic hepatitis C(CHC)is associated with type 2 diabetes mellitus.Although the pathogenesis remains to be elucidated,a growing evidence has suggested a role of pro-inflammatory immune response.Increased serum concentrations of Interleukin 6(IL-6)have been associated with insulin resistance,type 2 diabetes mellitus as well as advanced forms of liver disease in chronic hepatitis C infection.AIM To investigate the frequency of IL-6-174G/C(rs1800795)single nucleotide polymorphism(SNP)in CHC patients and in healthy subjects of the same ethnicity.Associations between type 2 diabetes mellitus(dependent variable)and demographic,clinical,nutritional,virological and,IL-6 genotyping data were also investigated in CHC patients.METHODS Two hundred and forty-five patients with CHC and 179 healthy control subjects(blood donors)were prospectively included.Type 2 diabetes mellitus was diagnosed according to the criteria of the American Diabetes Association.Clinical,biochemical,histological and radiological methods were used for the diagnosis of the liver disease.IL-6 polymorphism was evaluated by Taqman SNP genotyping assay.The data were analysed by logistic regression models.RESULTS Type 2 diabetes mellitus,blood hypertension and liver cirrhosis were observed in 20.8%(51/245),40.0%(98/245)and 38.4%(94/245)of the patients,respectively.The frequency of the studied IL-6 SNP did not differ between the CHC patients and controls(P=0.81)and all alleles were in Hardy-Weinberg equilibrium(P=0.38).In the multivariate analysis,type 2 diabetes mellitus was inversely associated with GC and CC genotypes of IL-6-174(OR=0.42;95%CI=0.22-0.78;P=0.006)and positively associated with blood hypertension(OR=5.56;95%CI=2.79-11.09;P<0.001).CONCLUSION This study was the first to show that GC and CC genotypes of IL-6-174 SNP are associated with a decreased risk of type 2 diabetes mellitus in patients chronically infected with hepatitis C virus.The identification of potential inflammatory mediators involved in the crosstalk between hepatitis C virus and the axis pancreas-liver remains important issues that deserve further investigations.展开更多
AIM: To evaluate in bile duct ligated rats whether there were progressive alterations of renal function without changes in histopathology. METHODS: Male Wistar rats were submitted to sham-surgery or bile duct ligation...AIM: To evaluate in bile duct ligated rats whether there were progressive alterations of renal function without changes in histopathology. METHODS: Male Wistar rats were submitted to sham-surgery or bile duct ligation (BDL) and divided according to the post-procedure time (2, 4 and 6-wk). To determine renal function parameters, rats wereplaced in metabolic cages and, at the end of the experiment, blood and urine samples were obtained. Histology and hydroxyproline content were analyzed in liver and renal tissue. RESULTS: Rats with 2 wk of BDL increased free water clearance (P = 0.02), reduced urinary osmolality (P = 0.03) and serum creatinine (P = 0.01) in comparison to the sham group. In contrast, rats at 6 wk of BDL showed features of HRS, including signif icant increase in serum creatinine and reductions in creatinine clearance, water excretion and urinary sodium concentration. Rats with 4 wk of BDL exhibited an intermediate stage of renal dysfunction. Progressive hepatic f ibrosis according to post-procedure time was confirmed by histology. The increased levels of liver hydroxyproline contrasted with the absence of structural changes in the kidney, as assessed by histology and unchanged hydroxyproline content in renal tissue. CONCLUSION: Our data show that BDL produced progressive renal dysfunction without structural changes in the kidney, characterizing HRS. The present model will be useful to understand the pathophysiology of HRS.展开更多
Mixtures of cereals and legumes result in products with higher content of high biological value proteins. The thermoplastic extrusion promotes the transformation of chemical, physical and nutritional characteristics o...Mixtures of cereals and legumes result in products with higher content of high biological value proteins. The thermoplastic extrusion promotes the transformation of chemical, physical and nutritional characteristics of the food such as starch gelatinization and promotes the inactivation of anti-nutritional compounds and enzymes. This study aimed to develop products extruded using broken rice and lupine and to evaluate the physical and chemical characteristics of those products. The expansion index (EI), water solubility (WSI), water absorption (WAI), texture and color were determined for the extruded rice, and Scanning Electron Microscopy (SEM) of the extruded rice was also performed. As the rice concentration in the mixture increased, the EI, WSI and WAI values as well as the a* color parameter were increased too, and the brightness was reduced. An increase in the levels of essential amino acids with the addition of lupine grain to the extrudates was observed. SEM analysis identified intact loose starch granules or pellets in the raw materials, and the extruded samples showed a compact and amorphous shape without apparent starch granules. Due to the structural changes and reduced expansion rate of the extruded mixture prepared with lupine and rice grits, use of the extruded mixtures as snacks would not be suitable. However, these mixtures could be used in pre-gelatinized flour to formulate various products to increase the protein level.展开更多
AIM To evaluate bacterial resistance to clarithromycin and fluoroquinolones in Brazil using molecular methods.METHODS The primary antibiotic resistance rates of Helicobacter pylori(H. pylori) were determined from Nove...AIM To evaluate bacterial resistance to clarithromycin and fluoroquinolones in Brazil using molecular methods.METHODS The primary antibiotic resistance rates of Helicobacter pylori(H. pylori) were determined from November 2012 to March 2015 in the Southern,South-Eastern,Northern,North-Eastern,and Central-Western regions of Brazil. Four hundred ninety H. pylori patients [66% female,mean age 43 years(range: 18-79)] who had never been previously treated for this infection were enrolled. All patients underwent gastroscopy with antrum and corpus biopsies and molecular testing using Geno Type Helico DR(Hain Life Science,Germany). This test was performed to detect the presence of H. pylori and to identify point mutations in the genes responsible for clarithromycin and fluoroquinolone resistance. The molecular procedure was divided into three steps: DNA extraction from the biopsies,multiplex amplification,and reverse hybridization. RESULTS Clarithromycin resistance was found in 83(16.9%) patients,and fluoroquinolone resistance was found in 66(13.5%) patients. There was no statistical difference in resistance to either clarithromycin or fluoroquinolones(P = 0.55 and P = 0.06,respectively) among the different regions of Brazil. Dual resistance to clarithromycin and fluoroquinolones was found in 4.3%(21/490) of patients. The A2147 G mutation was present in 90.4%(75/83),A2146 G in 16.9%(14/83) and A2146 C in 3.6%(3/83) of clarithromycin-resistant patients. In 10.8%(9/83) of clarithromycin-resistant samples,more than 01 mutation in the 23 S r RNA gene was noticed. In fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. D91 N mutation was observed in 34.8%(23/66),D91 G in 18.1%(12/66),N87 K in 16.6%(11/66) and D91 Y in 13.6%(9/66) of cases. Among fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. CONCLUSION The H. pylori clarithromycin resistance rate in Brazil is at the borderline(15%-20%) for applying the standard triple therapy. The fluoroquinolone resistance rate(13.5%) is equally concerning.展开更多
Raman probing of carbon electrode and electrolyte under dynamic conditions is performed here using different aqueous electrolytes to elucidate the fundamental events occurring in electrochemical supercapacitor during ...Raman probing of carbon electrode and electrolyte under dynamic conditions is performed here using different aqueous electrolytes to elucidate the fundamental events occurring in electrochemical supercapacitor during charge–discharge processes.The areal capacitance ranges from 1.54 to 2.31μF cm^(-2)μm and it is determined using different techniques.These findings indicate that the Helmholtz capacitance governs the overall charge-storage process instead of the space charge(quantum)capacitance commonly verified for HOPG electrodes in the range of~3 to 7μF cm^(-2).Molecular dynamics simulations are employed to elucidate the origin of the reversible Raman spectral changes during the charge–discharge processes.A correlation is verified between the reversible Raman shift and the surface excesses of the different ionic species.A theoretical framework is presented to relate the effect of the applied potential on the Raman shift and its correlation with the surface ionic charge.It is proposed that the Raman shift is governed by the interaction of solvated cations with graphite promoted by polarization conditions.It is the first time that a comparative study on different aqueous electrolyte p H and cation ion size has been performed tracking the Raman spectra change under dynamic polarization conditions and contrasting with comprehensive electrochemistry and dynamic molecular simulations studies.This study shines lights onto the charge-storage mechanism with evidence of Kohn anomaly reduction in the carbon electrode during the reversible adsorption/desorption and insertion/extraction of ionic species.展开更多
In the last years, the production of optical fibers cables has made possible the development of a range of spectroscopic probes for in situ analysis performing beyond nondestructive tests, environmental monitoring, se...In the last years, the production of optical fibers cables has made possible the development of a range of spectroscopic probes for in situ analysis performing beyond nondestructive tests, environmental monitoring, security investigation, application in radiotherapy for dose monitoring, verification and validation. In this work, a system using an optical fiber cable to electromagnetic signal transmission from a NaI(TI) radiation detector is presented. The innovative device takes advantage mainly of the optical fibers large passband, small signal attenuation and immunity to electromagnetic interference to application for radiation detection systems. The main aim was to simplify the detection system making it to reach areas where the conventional device cannot access due to its lack of mobility and external dimensions. Some tests with this innovative system are presented and the results stimulate the continuity of the researches.展开更多
Seed size is a plastic trait of the plants that directly affect seed germination and seedling recruitment. This study aimed to investigate the relationship between seed size, seed germinability and seedling performanc...Seed size is a plastic trait of the plants that directly affect seed germination and seedling recruitment. This study aimed to investigate the relationship between seed size, seed germinability and seedling performance of Copaifera langsdorffii by testing four hypotheses: 1) larger seeds have higher germination percentage;2) smaller seeds require less time to germinate and for initial development of the seedlings;3) larger seeds produce more vigorous seedlings and 4) seed size negatively affects seedling root/shoot ratio. In 2011, we selected 30 individuals of C. langsdorffii from which 300 seeds were randomly collected in the plant canopy. All these seeds were weighted and placed in germination tray using vermiculite as substrate. Seed germinability and initial development of seedlings were monitored daily until cotyledons fell. Small seeds have higher germination percentage and germinate faster when compared to large seeds. Nonetheless, seedlings originated from larger seeds have longer development times, resulting in more vigorous seedlings. In addition, seedlings originating from small seeds allocate proportionally greater amount of resources to roots when compared to larger seeds. The fact that small seeds have higher germination percentage and faster germination favors the colonization of transient habitats. However, larger seeds produce more vigorous seedlings, favoring the seedling establishment in more stable habitats. Thus, we argue that high variability in seed size of C. langsdorffii favors its widespread geographic distribution.展开更多
The hexagonal boron nitride has been well investigated. Its layered structure is similar to that of graphite. In the manufacture of cosmetics, this structure is intended to improve the appearance, sensory aspect and m...The hexagonal boron nitride has been well investigated. Its layered structure is similar to that of graphite. In the manufacture of cosmetics, this structure is intended to improve the appearance, sensory aspect and makes it easy to mix excipients contained in the formulation in the mixture process. In cosmetology, the efficiency and the penetration of active substances into skin are known to be directly related to the particle size. However, only recently their nanostructured properties have been explored. In this work, the synthesis of hexagonal boron nitride in the nanoscale, its composition, structure, morphology and potential for future application in sunscreens are being investigated. The boron nitride was synthesized from boric acid and melamine to a heat treatment at 1600℃. The crystal structure was characterized by (XRD) and its morphology was examined by (SEM) and (TEM);the chemical composition was studied by (FTIR), (EDS) and (EELS), the texture characterization by (BET) and its potential in sunscreens by (FTIR and UV/VIS). Results have shown that boron nitride may be synthesized in the nanoscale and that this material has the potential to be incorporated into cosmetics.展开更多
BACKGROUND Patients undergoing solid organ transplantation,particularly those who live or have lived in tuberculosis(TB)endemic areas,are at a high risk of developing TB.The majority of post-transplantation TB cases a...BACKGROUND Patients undergoing solid organ transplantation,particularly those who live or have lived in tuberculosis(TB)endemic areas,are at a high risk of developing TB.The majority of post-transplantation TB cases are associated with reactivation of latent TB infection(LTBI).Brazil is in a single position with overlapping areas of high TB endemicity and high transplant activity.In liver transplant(LT),one should be aware of the potential hepatotoxicity associated with the treatment regimens for LTBI.AIM To evaluate the frequency of LTBI in LT patients and treatment-related issues.METHODS This was a retrospective analysis of a cohort of cirrhotic patients aged≥18 years,who underwent LT at a high-complexity teaching hospital from January 2005 to December 2012.RESULTS Overall,429 patients underwent LT during the study period.Of these,213(49.7%)underwent the tuberculin skin test(TST)during the pre-transplant period,and 35(16.4%)of them had a positive result.The treatment for LTBI was initiated after LT in 12(34.3%)of the TST-positive patients;in 3(25.0%),treatment was maintained for at least 6 mo.CONCLUSION The prevalence of LTBI was lower than expected.Initiation and completion of LTBI treatment was limited by difficulties in the management of these special patients.展开更多
Land Sparing (LSP) was proposed to spatially segregate biodiversity and production in order to maximize both, while Land Sharing (LSH) defenders posit that farming and nature integration is preferable, through eco-agr...Land Sparing (LSP) was proposed to spatially segregate biodiversity and production in order to maximize both, while Land Sharing (LSH) defenders posit that farming and nature integration is preferable, through eco-agriculture and low-input systems. Based on a multidisciplinary review on historical land-use data, ecological aspects, agricultural production potential, economic and food security topics, we summarize LSP/LSH major findings and caveats. Although LSH still has to address some issues, LSP relies on a series of assumptions that are not supported by data, particularly regarding the positive effects of intensification on agriculture expansion. Furthermore, we developed conceptual models to theoretically predict the responses of biodiversity and ecosystems services in dynamic landscapes with different natural habitat proportions and different intensification levels on the farmed areas. Agriculture intensification may expand farmland reducing habitat area fostering population declines at the “natural” patches (via habitat reduction and decreasing species intra patch flux through the matrix), as well as at the farm site by direct effect of intensification (heterogeneity reduction and pesticide use), leading to a species extinction and ecosystems services loss. This multiple negative effect of agriculture intensification is worsening in regions where habitat proportion is below 30%, such as in many tropical biodiversity hotspots, making LSH a much safer strategy for conservation and food security.展开更多
Frailty is an important and complex phenomenon in the fields of geriatrics and gerontology and a highly relevant topic. Frailty syndrome (FS) is a multidimensional clinical condition characterized by loss of physiolog...Frailty is an important and complex phenomenon in the fields of geriatrics and gerontology and a highly relevant topic. Frailty syndrome (FS) is a multidimensional clinical condition characterized by loss of physiological and cognitive reserves across multiple organ systems. The Fried frailty phenotype is the main model used to categorize FS. Recent studies have shown an association between anemia, low hemoglobin concentration and frailty. This study aimed to assess the association between FS and anemia in community-dwelling elderly. An observational cross-sectional design was used, with 308 elderly subjects. Most participants were women (78.2%) between 60 and 69 years old (50.6%). The average schooling level was 9.7 years. Anemia was detected in 9.7% of participants. The frequency of frailty, pre-frailty and non-frailty was 8.2, 74.0 and 17.8%, respectively. The multivariate ordinal logistic regression model identified low levels of brain-derived neurotrophic factor (BDNF) (OR = 0.9, 95% CI = 0.9;0.9) as risk factor associated with FS. No significant association was found between frailty and anemia. Moreover, FS may be influenced by low schooling levels, despite the non-significant result obtained in the statistical model. These findings contribute to elucidating other factors associated with FS, especially in community-dwelling elderly.展开更多
文摘The soils of Brazilian Cerrado are characterized with high acidity and low fertility and productivity.However,these attributes are not homogeneously distributed through all phytophysiognomies of this biome,and wetland known as palm swamp or“veredas”are an exception.This study aimed to describe and compare the chemical and physical attributes of soil surface layers at six palm swamps areas under different anthropization processes in the northern region of Minas Gerais state,Brazil.Soil sampling of different hydromorphic soils were collected at 0-20 cm depth layer from 100 m2 plots in the studied areas.The variables were compared using the GLM procedure of ANOVA using Statistica 10 software.Soil chemical attributes and similarities between the six palm swamps areas were compared using the statistical software R.Soil chemical attributes were different and soil physical attributes were similar between the evaluated areas.The similarities among the attributes were classified into three groups according to the anthropic pressures,as well as with the origin of the soil material in the six palm swamps areas evaluated.It could be concluded that soil fertility can be reduced in palm swamps that suffered greater anthropic intervention.The three similarity groups might be associated not only to the anthropic pressures,but also to the raw material of soil at the six palm swamps areas evaluated.
文摘The objective of this study was to evaluate the chemical and physical attributes of soil, and the productivity of Eucalyptus cultivated in monoculture and silvopastoral systems. The experiment started in 2009 and evaluated the following four systems: native vegetation system (Cerrado), a degraded pasture, a Eucalyptus urograndis monoculture (E. urophylla x E. grandis) and a silvopastoral system (E. urograndis combined with Brachiaria brizantha cv. "Marandu"). The experimental design used was completely randomized. In each system, four soil samples were collected from the 0-20 cm depth layer, and the chemical and physical attributes of the soil were evaluated. The diameters of all Eucalyptus trees at 1.30 m above the ground as well as the total height were measured. Subsequently, the trees dimensions were measured and their individual volumes obtained by applying the Smalian formula. The correlation between the parameters for Eucalyptus production and soil attributes was established using the Pearson's correlation coefficient method. The planting of Eucalyptus in monoculture and silvopastoral systems contributed to the improvement of the soil's chemical and physical attributes, which indicates the potential of these systems for recovery of degraded pastures. The silvopastoral system yielded the highest average volume of wood per tree (0.2228 m^3), with a productivity of 111.4 m^3/ha. The Eucalyptus monoculture yielded 0.1895 m^3 per tree and 315.71 m^3/ha due to the higher density of the crop. The growth and productivity of Eucalyptus showed highly correlation with the soil attributes, thus suggesting that well-managed crops are an indicator of the soil quality recovery.
基金funded by Fundacao de Amparo a Pesquisa do Estado de Minas Gerais(FAPEMIG),Conselho Nacional de Desenvolvimento Cientifico e Tecnologico(CNPq),Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior(CAPES).
文摘Curimat?-pioa (Prochilodus costatus) and curimat?-pacu (Prochilodus argenteus) are migratory fish species endemic to the S?o Francisco River Basin in Brazil. Both species play important roles in local fisheries and ecology in the Paraopeba River. A dam was recently constructed on this river and to help in the development and conservation programs, we characterized the genetic variation of both species before dam construction. Complex hypervariable repeats micro-satellite was used to asses genetic variation for both species within and between the five collection sites in order to detect population substructuring. Nucleotide substitutions and insertion/deletion polymorphisms (indels) resulted in 35 P. costatus haplotypes (sample size = 89) and 22 P. argenteus haplotypes (sample size = 32). Significant genetic diversity and population differentiation was detected between five sampling sites for both species. Therefore, each of the five sites should be regarded as a group comprising significant genetic differences in species conservation and maintenance plans. Comparing these results to genetic diversity measures after dam construction will be critical for future management in this region.
文摘The Zika virus(ZIKV),a member of the Flaviviridae family,attracted worldwide attention for its connection to severe neurological effects,notably microcephaly in newborns,first reported during the 2015 epidemic in Brazil.Yet,its impact goes beyond fetal and neonatal abnormalities,also affecting the central nervous system(CNS)in both children and adults,leading to enduring cognitive and behavioral impairments.
基金Supported by Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES)Conselho Nacional de Desenvolvmento Científico e Tecnológico(CNPq)Fundacao de AmparoàPesquisa do estado de Minas Gerais(FAPEMIG)
文摘Stem cell therapy is a promising approach to clinical healing in several diseases. A great variety of tissues(bone marrow, adipose tissue, and placenta) arepotentially sources of stem cells. Placenta-derived stem cells(p-SCs) are in between embryonic and mesenchymal stem cells, sharing characteristics with both, such as non-carcinogenic status and property to differentiate in all embryonic germ layers. Moreover, their use is not ethically restricted as fetal membranes are considered medical waste after birth. In this context, the present review will be focused on the biological properties, culture and potential cell therapy uses of placental-derived stem cells. Immunophenotype characterization, mainly for surface marker expression, and basic principles of p-SC isolation and culture(mechanical separation or enzymatic digestion of the tissues, the most used culture media, cell plating conditions) will be presented. In addition, some preclinical studies that were performed in different medical areas will be cited, focusing on neurological, liver, pancreatic, heart, muscle, pulmonary, and bone diseases and also in tissue engineering field. Finally, some challenges for stem cell therapy applications will be highlighted. The understanding of the mechanisms involved in the p-SCs differentiation and the achievement of pure cell populations(after differentiation) are key points that must be clarified before bringing the preclinical studies, performed at the bench, to the medical practice.
基金Supported by the Oswaldo Cruz Foundation(FIOCRUZ)the Pernambuco Science and Technology Support Foundation(FACEPE)(PROEP-FIOCRUZ 19/2015)+2 种基金the National Council of Technological and Scientific Development(CNPq)(Processes APQ 0906-2.11/08)the National Council for the Improvement of Higher Education(CAPES)the Intramural Research Program of the National Institutes of Health(LPD/NIAID/NIH)
文摘To evaluate the therapeutic effects of bone marrow-derived CD11b<sup>+</sup>CD14<sup>+</sup> monocytes in a murine model of chronic liver damage.METHODSChronic liver damage was induced in C57BL/6 mice by administration of carbon tetrachloride and ethanol for 6 mo. Bone marrow-derived monocytes isolated by immunomagnetic separation were used for therapy. The cell transplantation effects were evaluated by morphometry, biochemical assessment, immunohistochemistry and enzyme-linked immunosorbent assay.RESULTSCD11b<sup>+</sup>CD14<sup>+</sup> monocyte therapy significantly reduced liver fibrosis and increased hepatic glutathione levels. Levels of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-6 and IL-1β, in addition to pro-fibrotic factors, such as IL-13, transforming growth factor-β1 and tissue inhibitor of metalloproteinase-1 also decreased, while IL-10 and matrix metalloproteinase-9 increased in the monocyte-treated group. CD11b<sup>+</sup>CD14<sup>+</sup> monocyte transplantation caused significant changes in the hepatic expression of α-smooth muscle actin and osteopontin.CONCLUSIONMonocyte therapy is capable of bringing about improvement of liver fibrosis by reducing oxidative stress and inflammation, as well as increasing anti-fibrogenic factors.
文摘Parkinson’s disease is the most common movement disorder,affecting about 1%of the population over the age of 60 years.Parkinson’s disease is characterized clinically by resting tremor,bradykinesia,rigidity and postural instability,as a result of the progressive loss of nigrostriatal dopaminergic neurons.In addition to this neuronal cell loss,Parkinson’s disease is characterized by the accumulation of intracellular protein aggregates,Lewy bodies and Lewy neurites,composed primarily of the proteinα-synuclein.Although it was first described almost 200 years ago,there are no disease-modifying drugs to treat patients with Parkinson’s disease.In addition to conventional therapies,non-pharmacological treatment strategies are under investigation in patients and animal models of neurodegenerative disorders.Among such strategies,environmental enrichment,comprising physical exercise,cognitive stimulus,and social interactions,has been assessed in preclinical models of Parkinson’s disease.Environmental enrichment can cause structural and functional changes in the brain and promote neurogenesis and dendritic growth by modifying gene expression,enhancing the expression of neurotrophic factors and modulating neurotransmission.In this review article,we focus on the current knowledge about the molecular mechanisms underlying environmental enrichment neuroprotection in Parkinson’s disease,highlighting its influence on the dopaminergic,cholinergic,glutamatergic and GABAergic systems,as well as the involvement of neurotrophic factors.We describe experimental pre-clinical data showing how environmental enrichment can act as a modulator in a neurochemical and behavioral context in different animal models of Parkinson’s disease,highlighting the potential of environmental enrichment as an additional strategy in the management and prevention of this complex disease.
基金the“Fundamental Research Funds for the Chinese Central Universities”(Grant No.2017CXNL03)the Chinese Scholarship Council(Grant No.2015120T19).
文摘The discovery of the Gouap banded iron formations(BIFs)-hosted iron mineralization in the northwestern of the Nyong Group(Ntem Complex)in southwestern Cameroon provides unique insights into the geology of this region.In this contribution,we firstly report detailed study of geochemistry,isotopic and geochronology of well preserved samples of the Gouap BIFs collected from diamond drillcores.The Gouap BIFs consist mainly of amphibole BIFs and amphibole-pyrite BIFs characterized by dominant Fe_(2)O_(3)+SiO_(2)contents and variable contents of CaO,MgO and SO_(3),consistent with the presence of amphibole,chlorite,epidote and pyrite,formed during amphibolite facies metamorphism and overprinted hydrothermal event.The amphibole–pyrite BIFs are typically enriched in trace and rare earth elements(REE)compared to the amphibole BIFs,suggesting the influence of detrital materials as well as secondary hydrothermal alteration.The Post Archean Australian Shale(PAAS)-normalized REE–Y profiles of the Gouap BIFs display positive La,Eu anomalies,weak negative Ce anomalies,indicating a mixture of low-temperature hydrothermal fluids and relatively oxic conditions probably under relative shallow seawater.We present here the first isotopic data of BIFs within the Ntem Complex.Theδ^(30)Si_(NBS28)values of the quartz from the Gouap BIFs vary from-1.5‰to-0.3‰and from-0.8‰to-0.9‰for the amphibole BIFs and amphibole–pyrite BIFs,respectively.The quartz hasδ^(18)OV-SMOW values of 6.8‰–9.5‰(amphibole BIFs)and 9.2‰–10.6‰(amphibole–pyrite BIFs).The magnetite from the Gouap BIFs showsδ^(18)O values ranging from-3.5‰to-1.8‰and from-3‰to-1.7‰for the amphibole BIFs and amphibole–pyrite BIFs,respectively.Moreover,the pyrite grains in the amphibole–pyrite BIFs displayδ34S values of 1.1‰–1.8‰.All isotopic data of the Gouap BIFs confirm that they might have precipitated from low-temperature hydrothermal fluids with detrital input distant from the volcanic activity.According to their geochemical and isotopic characteristics,we propose that the Gouap BIFs belong to the Superior type.In situ U–Pb zircon dating of BIFs was conducted to assess the BIF depositional age based on strong evidence of zircon in thin section.The Gouap BIFs were probably deposited at 2422±50 Ma in a region where sediments extended from continental shelf to deep-water environments along craton margins like the Caue Formation of the Minas Supergroup,Brazil.The studied BIFs have experienced regional hydrothermal activity and metamorphism at 2089±8.3 Ma during the Eburnean–Transamazonian orogeny.These findings suggest a physical continuity between the protocratonic masses of both Sao Francisco and Congo continents in the Rhyacian Period.
基金Supported by Humberto Corrêa has received research funding from Fundacao de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
文摘Postpartum depression is one of the most prevalent psychopathologies. Its prevalence is estimated to be between 10% and 15%. Despite its multifactorial etiology, it is known that genetics play an important role in the genesis of this disorder. This paper reviews epidemiological evidence supporting the role of genetics in postpartum depression(PPD). The main objectives of this review are to determine which genes and polymorphisms are associated with PPD and discuss how this association may occur. In addition, this paper explores whether these genes are somehow related to or even the same as those linked to Major Depression(MD). To identify gaps in the current knowledge that require investigation, a systematic review was conducted in the electronic databases Pub Med, LILACS and Sci ELO using the index terms "postpartum depression" and "genetics". Literature searches for articles in peerreviewed journals were made until April 2014. PPD was indexed 56 times with genetics. The inclusion criteria were articles in Portuguese, Spanish or English that were available by institutional means or sent by authors upon request; this search resulted in 20 papers. Genes and polymorphisms traditionally related to MD, which are those involved in the serotonin, catecholamine, brain-derived neurotrophic factor and tryptophan metabolism, have been the most studied, and some have been related to PPD. The results are conflicting and some depend on epigenetics, which makes the data incipient. Further studies are required to determine the genes that are involved in PPD and establish the nature of the relationship between these genes and PPD.
基金Fundationde AmparoàPesquisa do Estado de Minas Gerais,No.APQ-02320-18.
文摘BACKGROUND Chronic hepatitis C(CHC)is associated with type 2 diabetes mellitus.Although the pathogenesis remains to be elucidated,a growing evidence has suggested a role of pro-inflammatory immune response.Increased serum concentrations of Interleukin 6(IL-6)have been associated with insulin resistance,type 2 diabetes mellitus as well as advanced forms of liver disease in chronic hepatitis C infection.AIM To investigate the frequency of IL-6-174G/C(rs1800795)single nucleotide polymorphism(SNP)in CHC patients and in healthy subjects of the same ethnicity.Associations between type 2 diabetes mellitus(dependent variable)and demographic,clinical,nutritional,virological and,IL-6 genotyping data were also investigated in CHC patients.METHODS Two hundred and forty-five patients with CHC and 179 healthy control subjects(blood donors)were prospectively included.Type 2 diabetes mellitus was diagnosed according to the criteria of the American Diabetes Association.Clinical,biochemical,histological and radiological methods were used for the diagnosis of the liver disease.IL-6 polymorphism was evaluated by Taqman SNP genotyping assay.The data were analysed by logistic regression models.RESULTS Type 2 diabetes mellitus,blood hypertension and liver cirrhosis were observed in 20.8%(51/245),40.0%(98/245)and 38.4%(94/245)of the patients,respectively.The frequency of the studied IL-6 SNP did not differ between the CHC patients and controls(P=0.81)and all alleles were in Hardy-Weinberg equilibrium(P=0.38).In the multivariate analysis,type 2 diabetes mellitus was inversely associated with GC and CC genotypes of IL-6-174(OR=0.42;95%CI=0.22-0.78;P=0.006)and positively associated with blood hypertension(OR=5.56;95%CI=2.79-11.09;P<0.001).CONCLUSION This study was the first to show that GC and CC genotypes of IL-6-174 SNP are associated with a decreased risk of type 2 diabetes mellitus in patients chronically infected with hepatitis C virus.The identification of potential inflammatory mediators involved in the crosstalk between hepatitis C virus and the axis pancreas-liver remains important issues that deserve further investigations.
基金FAPEMIG (Funda■o de Amparo à Pesquisa do Estado de Minas Gerais)CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico)PRONEX (Grupos de Excelência)
文摘AIM: To evaluate in bile duct ligated rats whether there were progressive alterations of renal function without changes in histopathology. METHODS: Male Wistar rats were submitted to sham-surgery or bile duct ligation (BDL) and divided according to the post-procedure time (2, 4 and 6-wk). To determine renal function parameters, rats wereplaced in metabolic cages and, at the end of the experiment, blood and urine samples were obtained. Histology and hydroxyproline content were analyzed in liver and renal tissue. RESULTS: Rats with 2 wk of BDL increased free water clearance (P = 0.02), reduced urinary osmolality (P = 0.03) and serum creatinine (P = 0.01) in comparison to the sham group. In contrast, rats at 6 wk of BDL showed features of HRS, including signif icant increase in serum creatinine and reductions in creatinine clearance, water excretion and urinary sodium concentration. Rats with 4 wk of BDL exhibited an intermediate stage of renal dysfunction. Progressive hepatic f ibrosis according to post-procedure time was confirmed by histology. The increased levels of liver hydroxyproline contrasted with the absence of structural changes in the kidney, as assessed by histology and unchanged hydroxyproline content in renal tissue. CONCLUSION: Our data show that BDL produced progressive renal dysfunction without structural changes in the kidney, characterizing HRS. The present model will be useful to understand the pathophysiology of HRS.
文摘Mixtures of cereals and legumes result in products with higher content of high biological value proteins. The thermoplastic extrusion promotes the transformation of chemical, physical and nutritional characteristics of the food such as starch gelatinization and promotes the inactivation of anti-nutritional compounds and enzymes. This study aimed to develop products extruded using broken rice and lupine and to evaluate the physical and chemical characteristics of those products. The expansion index (EI), water solubility (WSI), water absorption (WAI), texture and color were determined for the extruded rice, and Scanning Electron Microscopy (SEM) of the extruded rice was also performed. As the rice concentration in the mixture increased, the EI, WSI and WAI values as well as the a* color parameter were increased too, and the brightness was reduced. An increase in the levels of essential amino acids with the addition of lupine grain to the extrudates was observed. SEM analysis identified intact loose starch granules or pellets in the raw materials, and the extruded samples showed a compact and amorphous shape without apparent starch granules. Due to the structural changes and reduced expansion rate of the extruded mixture prepared with lupine and rice grits, use of the extruded mixtures as snacks would not be suitable. However, these mixtures could be used in pre-gelatinized flour to formulate various products to increase the protein level.
基金Supported by Pró-Reitoria de Pesquisa da Universidade Federal de Minas Gerais,Fundacao de AmparoàPesquisa do Estado de Minas Gerais(FAPEMIG)and Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq),Brazil
文摘AIM To evaluate bacterial resistance to clarithromycin and fluoroquinolones in Brazil using molecular methods.METHODS The primary antibiotic resistance rates of Helicobacter pylori(H. pylori) were determined from November 2012 to March 2015 in the Southern,South-Eastern,Northern,North-Eastern,and Central-Western regions of Brazil. Four hundred ninety H. pylori patients [66% female,mean age 43 years(range: 18-79)] who had never been previously treated for this infection were enrolled. All patients underwent gastroscopy with antrum and corpus biopsies and molecular testing using Geno Type Helico DR(Hain Life Science,Germany). This test was performed to detect the presence of H. pylori and to identify point mutations in the genes responsible for clarithromycin and fluoroquinolone resistance. The molecular procedure was divided into three steps: DNA extraction from the biopsies,multiplex amplification,and reverse hybridization. RESULTS Clarithromycin resistance was found in 83(16.9%) patients,and fluoroquinolone resistance was found in 66(13.5%) patients. There was no statistical difference in resistance to either clarithromycin or fluoroquinolones(P = 0.55 and P = 0.06,respectively) among the different regions of Brazil. Dual resistance to clarithromycin and fluoroquinolones was found in 4.3%(21/490) of patients. The A2147 G mutation was present in 90.4%(75/83),A2146 G in 16.9%(14/83) and A2146 C in 3.6%(3/83) of clarithromycin-resistant patients. In 10.8%(9/83) of clarithromycin-resistant samples,more than 01 mutation in the 23 S r RNA gene was noticed. In fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. D91 N mutation was observed in 34.8%(23/66),D91 G in 18.1%(12/66),N87 K in 16.6%(11/66) and D91 Y in 13.6%(9/66) of cases. Among fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. CONCLUSION The H. pylori clarithromycin resistance rate in Brazil is at the borderline(15%-20%) for applying the standard triple therapy. The fluoroquinolone resistance rate(13.5%) is equally concerning.
基金the financial support from the Brazilian funding agencies CNPq(301486/2016-6)the FAEPEX(2426/17),the FAPESP(2016/25082-8,2017/11958-1,2014/02163-7,2018/20756-6,2018/02713-8)and CAPES(1740195)+6 种基金the‘‘Funda??o ao AmparoàPesquisa do Estado de Minas Gerais-FAPEMIG”(Project CEX112-10)the‘‘Secretaria de Estado de Ciência,Tecnologia e Ensino Superior de Minas Gerais-SECTES/MG”(Support for the LMMA Laboratory)the‘‘Conselho Nacional de Desenvolvimento Científico e Tecnológico–CNPq”(PQ-2 grant)support Shell and the strategic importance of the support given by ANP(Brazil’s National Oil,Natural Gas and Biofuels Agency)through the R&D levy regulationthe Center for Research Computing(CRC)at the University of Notre Dame for the computational resources,and the Brazilian agencies CNPq(Reference Number 203393/2018-0)and CAPES(Finance Code 001)for the financial supportfinancial support from the FAPEMIG,CNPq(307742/2017-2 and 432384/2018-9)Brazilian Institute of Science and Technology in Carbon Nanomaterials(INCTNanocarbono)。
文摘Raman probing of carbon electrode and electrolyte under dynamic conditions is performed here using different aqueous electrolytes to elucidate the fundamental events occurring in electrochemical supercapacitor during charge–discharge processes.The areal capacitance ranges from 1.54 to 2.31μF cm^(-2)μm and it is determined using different techniques.These findings indicate that the Helmholtz capacitance governs the overall charge-storage process instead of the space charge(quantum)capacitance commonly verified for HOPG electrodes in the range of~3 to 7μF cm^(-2).Molecular dynamics simulations are employed to elucidate the origin of the reversible Raman spectral changes during the charge–discharge processes.A correlation is verified between the reversible Raman shift and the surface excesses of the different ionic species.A theoretical framework is presented to relate the effect of the applied potential on the Raman shift and its correlation with the surface ionic charge.It is proposed that the Raman shift is governed by the interaction of solvated cations with graphite promoted by polarization conditions.It is the first time that a comparative study on different aqueous electrolyte p H and cation ion size has been performed tracking the Raman spectra change under dynamic polarization conditions and contrasting with comprehensive electrochemistry and dynamic molecular simulations studies.This study shines lights onto the charge-storage mechanism with evidence of Kohn anomaly reduction in the carbon electrode during the reversible adsorption/desorption and insertion/extraction of ionic species.
文摘In the last years, the production of optical fibers cables has made possible the development of a range of spectroscopic probes for in situ analysis performing beyond nondestructive tests, environmental monitoring, security investigation, application in radiotherapy for dose monitoring, verification and validation. In this work, a system using an optical fiber cable to electromagnetic signal transmission from a NaI(TI) radiation detector is presented. The innovative device takes advantage mainly of the optical fibers large passband, small signal attenuation and immunity to electromagnetic interference to application for radiation detection systems. The main aim was to simplify the detection system making it to reach areas where the conventional device cannot access due to its lack of mobility and external dimensions. Some tests with this innovative system are presented and the results stimulate the continuity of the researches.
基金financial support from Fundacao de Amparo a Pesquisa do Estado de Minas Gerais(FAPEMIG APQ 01926.11)Programa de Pos-Graduacao Stricto Sensu em Ciencias Biologicas(PPGCB)da UNIMONTESCAPES and FAPEMIG by research grants.
文摘Seed size is a plastic trait of the plants that directly affect seed germination and seedling recruitment. This study aimed to investigate the relationship between seed size, seed germinability and seedling performance of Copaifera langsdorffii by testing four hypotheses: 1) larger seeds have higher germination percentage;2) smaller seeds require less time to germinate and for initial development of the seedlings;3) larger seeds produce more vigorous seedlings and 4) seed size negatively affects seedling root/shoot ratio. In 2011, we selected 30 individuals of C. langsdorffii from which 300 seeds were randomly collected in the plant canopy. All these seeds were weighted and placed in germination tray using vermiculite as substrate. Seed germinability and initial development of seedlings were monitored daily until cotyledons fell. Small seeds have higher germination percentage and germinate faster when compared to large seeds. Nonetheless, seedlings originated from larger seeds have longer development times, resulting in more vigorous seedlings. In addition, seedlings originating from small seeds allocate proportionally greater amount of resources to roots when compared to larger seeds. The fact that small seeds have higher germination percentage and faster germination favors the colonization of transient habitats. However, larger seeds produce more vigorous seedlings, favoring the seedling establishment in more stable habitats. Thus, we argue that high variability in seed size of C. langsdorffii favors its widespread geographic distribution.
文摘The hexagonal boron nitride has been well investigated. Its layered structure is similar to that of graphite. In the manufacture of cosmetics, this structure is intended to improve the appearance, sensory aspect and makes it easy to mix excipients contained in the formulation in the mixture process. In cosmetology, the efficiency and the penetration of active substances into skin are known to be directly related to the particle size. However, only recently their nanostructured properties have been explored. In this work, the synthesis of hexagonal boron nitride in the nanoscale, its composition, structure, morphology and potential for future application in sunscreens are being investigated. The boron nitride was synthesized from boric acid and melamine to a heat treatment at 1600℃. The crystal structure was characterized by (XRD) and its morphology was examined by (SEM) and (TEM);the chemical composition was studied by (FTIR), (EDS) and (EELS), the texture characterization by (BET) and its potential in sunscreens by (FTIR and UV/VIS). Results have shown that boron nitride may be synthesized in the nanoscale and that this material has the potential to be incorporated into cosmetics.
基金The study was approved by the Federal University of Minas Gerais Research Ethics Committee(approval number:0614.0.203.000-11).
文摘BACKGROUND Patients undergoing solid organ transplantation,particularly those who live or have lived in tuberculosis(TB)endemic areas,are at a high risk of developing TB.The majority of post-transplantation TB cases are associated with reactivation of latent TB infection(LTBI).Brazil is in a single position with overlapping areas of high TB endemicity and high transplant activity.In liver transplant(LT),one should be aware of the potential hepatotoxicity associated with the treatment regimens for LTBI.AIM To evaluate the frequency of LTBI in LT patients and treatment-related issues.METHODS This was a retrospective analysis of a cohort of cirrhotic patients aged≥18 years,who underwent LT at a high-complexity teaching hospital from January 2005 to December 2012.RESULTS Overall,429 patients underwent LT during the study period.Of these,213(49.7%)underwent the tuberculin skin test(TST)during the pre-transplant period,and 35(16.4%)of them had a positive result.The treatment for LTBI was initiated after LT in 12(34.3%)of the TST-positive patients;in 3(25.0%),treatment was maintained for at least 6 mo.CONCLUSION The prevalence of LTBI was lower than expected.Initiation and completion of LTBI treatment was limited by difficulties in the management of these special patients.
文摘Land Sparing (LSP) was proposed to spatially segregate biodiversity and production in order to maximize both, while Land Sharing (LSH) defenders posit that farming and nature integration is preferable, through eco-agriculture and low-input systems. Based on a multidisciplinary review on historical land-use data, ecological aspects, agricultural production potential, economic and food security topics, we summarize LSP/LSH major findings and caveats. Although LSH still has to address some issues, LSP relies on a series of assumptions that are not supported by data, particularly regarding the positive effects of intensification on agriculture expansion. Furthermore, we developed conceptual models to theoretically predict the responses of biodiversity and ecosystems services in dynamic landscapes with different natural habitat proportions and different intensification levels on the farmed areas. Agriculture intensification may expand farmland reducing habitat area fostering population declines at the “natural” patches (via habitat reduction and decreasing species intra patch flux through the matrix), as well as at the farm site by direct effect of intensification (heterogeneity reduction and pesticide use), leading to a species extinction and ecosystems services loss. This multiple negative effect of agriculture intensification is worsening in regions where habitat proportion is below 30%, such as in many tropical biodiversity hotspots, making LSH a much safer strategy for conservation and food security.
文摘Frailty is an important and complex phenomenon in the fields of geriatrics and gerontology and a highly relevant topic. Frailty syndrome (FS) is a multidimensional clinical condition characterized by loss of physiological and cognitive reserves across multiple organ systems. The Fried frailty phenotype is the main model used to categorize FS. Recent studies have shown an association between anemia, low hemoglobin concentration and frailty. This study aimed to assess the association between FS and anemia in community-dwelling elderly. An observational cross-sectional design was used, with 308 elderly subjects. Most participants were women (78.2%) between 60 and 69 years old (50.6%). The average schooling level was 9.7 years. Anemia was detected in 9.7% of participants. The frequency of frailty, pre-frailty and non-frailty was 8.2, 74.0 and 17.8%, respectively. The multivariate ordinal logistic regression model identified low levels of brain-derived neurotrophic factor (BDNF) (OR = 0.9, 95% CI = 0.9;0.9) as risk factor associated with FS. No significant association was found between frailty and anemia. Moreover, FS may be influenced by low schooling levels, despite the non-significant result obtained in the statistical model. These findings contribute to elucidating other factors associated with FS, especially in community-dwelling elderly.