497 research outputs found
Low-density Lipoprotein Cholesterol And Radiotherapy-induced Carotid Atherosclerosis In Subjects With Head And Neck Cancer
Background: Radiotherapy (RT) is a risk factor for accelerated carotid artery atherosclerotic disease in subjects with head and neck cancer. However, the risk factors of RT-induced carotid artery remodeling are not established. This study aimed to investigate the effects of RT on carotid and popliteal arteries in subjects with head and neck cancer and to evaluate the relationship between baseline clinical and laboratory features and the progression of RT-induced atherosclerosis.Findings: Eleven men (age = 57.9 ± 6.2years) with head and neck cancer who underwent cervical bilateral irradiation were prospectively examined by clinical and laboratory analysis and by carotid and popliteal ultrasound before and after treatment (mean interval between the end of RT and the post-RT assessment = 181 ± 47 days). No studied subject used hypocholesterolemic medications. Significant increases in carotid intima-media thickness (IMT) (0.95 ± 0.08 vs. 0.87 ± 0.05 mm; p 3.0.CO;2-X, 626923Pereira Lima, M.N., Biolo, A., Foppa, M., da Rosa, P.R., Rohde, L.E., Clausell, N., A prospective, comparative study on the early effects of local and remote radiation therapy on carotid intima-media thickness and vascular cellular adhesion molecule-1 in patients with head and neck and prostate tumors (2011) Radiother Oncol, 101, pp. 449-453. , 10.1016/j.radonc.2010.03.026, 20435360Kalábová, H., Melichar, B., Ungermann, L., Doležal, J., Krčmová, L., Kašparová, M., Plíšek, J., Solichová, D., Intima-media thickness, myocardial perfusion and laboratory risk factors of atherosclerosis in patients with breast cancer treated with anthracycline-based chemotherapy (2011) Med Oncol, 28, pp. 1281-1287. , 10.1007/s12032-010-9593-1, 20567943Muzaffar, K., Collins, S.L., Labropoulos, N., Baker, W.H., A prospective study of the effects of irradiation on the carotid artery (2000) Laryngoscope, 110, pp. 1811-1814. , 10.1097/00005537-200011000-00007, 11081590Faruolo, M., Fiorentino, A., Gallucci, G., Lapadula, L., Fusco, V., Intimal-medial thickness and carotid arteries lumen in irradiated patients for head and neck cancer: preliminary data of an observational study (2013) Clin Transl Oncol, 15, pp. 861-864. , 10.1007/s12094-013-1023-3, 23463595Ferreira-Sae, M.C., Cipolli, J.A., Cornélio, M.E., Matos-Souza, J.R., Fernandes, M.N., Schreiber, R., Costa, F.O., Nadruz, W., Sodium intake is associated with carotid artery structure alterations and plasma matrix metalloproteinase-9 upregulation in hypertensive adults (2011) J Nutr, 141, pp. 877-882. , 10.3945/jn.110.135921, 21430243Gemignani, T., Azevedo, R.C., Higa, C.M., Coelho, O.R., Matos-Souza, J.R., Nadruz, W., Increased popliteal circumferential wall tension induced by orthostatic body posture is associated with local atherosclerotic plaques (2012) Atherosclerosis, 224, pp. 118-122. , 10.1016/j.atherosclerosis.2012.06.069, 2281862
Doença Pulmonar Obstrutiva Crónica em Portugal: estudo Pneumobil (1995) e estudo de prevalência de 2002 revisitados
ResumoIntroduçãoA doença pulmonar obstrutiva crónica (DPOC) tem sido, ao longo dos anos, uma importante causa de morbilidade e mortalidade no mundo. Em 1995, a implementação de um rastreio da função respiratória pareceu a forma mais adequada para alertar para os sintomas respiratórios negligenciados e sensibilizar para os rastreios espirométricos. Em 2002, foram criadas novas normas consensuais de diagnóstico e o reconhecimento de que a prevalência da DPOC depende dos critérios de definição de obstrução das vias aéreas. O objetivo deste estudo foi revisitar estes 2 estudos e publicar alguns dos resultados e respetivas metodologias.MétodosDos 12 684 indivíduos que constavam da base de dados do Pneumobil, apenas os indivíduos com 40 e mais anos (n = 9061) foram considerados para esta análise. No estudo de 2002 foi incluída uma amostra aleatorizada e representativa de 1384 indivíduos, com idades entre os 35 e os 69 anos.ResultadosA prevalência da DPOC foi de 8,96% no estudo Pneumobil e de 5,34% no estudo de 2002. Em ambos os estudos, a presença da DPOC foi superior no sexo masculino, tendo-se verificado uma associação positiva entre a presença da DPOC e os grupos etários mais velhos. Nos fumadores e ex-fumadores encontrou-se maior proporção de casos com DPOC.ConclusõesA prevalência em Portugal é mais baixa do que noutros países europeus, o que pode estar relacionado com uma menor prevalência de tabagismo. De um modo geral, os fatores de risco mais importantes que mostraram a associação com a DPOC foram a idade maior do que 60 anos, o sexo masculino e a exposição tabágica. Todos os aspetos e as limitações que se referem a diferentes critérios de definição e a metodologias de recrutamento realçam a necessidade de métodos padronizados para determinar a prevalência da DPOC e os fatores de risco associados, cujos resultados possam ser comparados entre países, como acontece no projeto BOLD.AbstractBackgroundChronic Obstructive Pulmonary Disease (COPD) has been a leading cause of morbidity and mortality worldwide, over the years. In 1995, the implementation of a respiratory function survey seemed to be an adequate way to draw attention to neglected respiratory symptoms and increase the awareness of spirometry surveys. By 2002 there were new consensual guidelines in place and the awareness that prevalence of COPD depended on the criteria used for airway obstruction definition. The purpose of this study is to revisit the two studies and to turn public some of the data and respective methodologies.MethodsFrom Pneumobil study database of 12,684 subjects, only the individuals with 40+ years old (n = 9.061) were selected. The 2002 study included a randomized representative sample of 1,384 individuals with 35-69 years old.ResultsThe prevalence of COPD was 8.96% in Pneumobil and 5.34% in the 2002 study. In both studies, presence of COPD was greater in males and there was a positive association between presence of COPD and older age groups. Smokers and ex-smokers showed a higher proportion of cases of COPD.ConclusionsPrevalence in Portugal is lower than in other European countries. This may be related to lower smokers’ prevalence. Globally, the most important risk factors associated with COPD were age over 60 years, male gender and smoking exposure. All aspects and limitations regarding different recruitment methodologies and different criteria for defining COPD cases highlight the need of a standardized method to evaluate COPD prevalence and associated risks factors, whose results can be compared across countries, as it is the case of BOLD project
Minimum mass of galaxies from BEC or scalar field dark matter
Many problems of cold dark matter models such as the cusp problem and the
missing satellite problem can be alleviated, if galactic halo dark matter
particles are ultra-light scalar particles and in Bose-Einstein condensate
(BEC), thanks to a characteristic length scale of the particles. We show that
this finite length scale of the dark matter can also explain the recently
observed common central mass of the Milky Way satellites ()
independent of their luminosity, if the mass of the dark matter particle is
about .Comment: 10 pages, 1 figure, accepted in JCA
The Electronic Smell of the Orchard Fruit
Assessing fruit maturity at the end of the season is a hard task for fruit growers. This task is either made by visual inspection – which is tedious and time consuming - or using destructive procedures for measuring biophysical properties of the fruits, such as the sugar content. An alternative to measure the ripeness of fruits is measuring the volatile organic compounds emitted by the fruits. An important compound produced by the fruits in this stage is ethylene (C2H4). The recent advances in electro chemical semiconductors have enabled the rapid growth of electronic noses technologies and applications. Nevertheless, the research reported where its characteristics and limitations are explored only addresses experiments in controlled and indoor settings.Therefore, many questions remain regarding the electronic noses applicability in outdoor environments. This work presents preliminary evidences that there are good chances that ethylene can be detected outdoors via an electronic nose placed within an orchard field. The results presented are measurements acquired in a Conference pear (Pyruscommunis) orchard in September 2017. The measurements where acquired on several points within the field, and the maximum ethylene detection shows an increase of 10% over 400 seconds. These results were contrasted with a theoretical study where gas dispersion patterns can be appreciated when subject to the wind speeds recorded in the field. The simulation results indicated a good correlation between the practical and the theoretical simulation results. To the best of our knowledge this work is the first to report results from measurements using electronic noses in a non-controlled environment, and detecting spatial-temporal variability of natural gas sources
Scalar Dark Matter From Theory Space
The scalar dark matter candidate in a prototypical theory space little Higgs
model is investigated. We review all details of the model pertinent to dark
matter. We perform a thermal relic density calculation including couplings to
the gauge and Higgs sectors of the model. We find two regions of parameter
space that give acceptable dark matter abundances. The first region has a dark
matter candidate with a mass of order 100 GeV, the second region has a heavy
candidate with a mass greater than about 500 GeV$. The dark matter candidate in
either region is an admixture of an SU(2) triplet and an SU(2) singlet, thereby
constituting a WIMP (weakly interacting massive particle).Comment: 18 pages, 2 figures, version to appear in PR
Transforming growth factor-β (TGF-β) maintains follicular ultrastructure and stimulates preantral follicle growth in caprine ovarian tissue cultured in vitro
O objetivo desse estudo foi investigar se o TGF-β afeta a sobrevivência, ativação e crescimento de folículos primordiais caprinos inclusos no córtex ovariano após o cultivo in vitro. Ovários de cabras foram coletados em abatedouro e fragmentos de tecido ovariano foram cultivados por um e sete dias em meio essencial mínimo alfa (α-MEM+) sozinho ou suplementado com TGF-β (1, 5, 10 ou 50ng/mL). Fragmentos ovarianos não cultivados e cultivados foram processados para análise histológica e ultraestrutural. Os resultados mostraram que, comparado ao controle fresco, houve diminuição no percentual de folículos morfologicamente normais em todos os tratamentos somente após sete dias de cultivo. O TGF-β não afetou a ativação folicular independente da concentração testada, contudo, o diâmetro folicular foi superior (P<0.05) no tratamento com 10ng/mL de TGF-β quando comparado ao controle fresco e aos demais tratamentos. Além disso, essa mesma concentração manteve a ultraestrutura normal dos folículos após sete dias de cultivo. Em conclusão, o TGF-β apresentou efeito adicional no crescimento folicular e na manutenção da integridade ultraestrutural de folículos pré-antrais caprinos inclusos no tecido ovariano quando utilizado na concentração de 10ng/mL durante sete dias de cultivo.The objectives of this study were to investigate whether TGF-β affect the survival, activation and further growth of goat primordial follicles enclosed in ovarian cortex after in vitro culture. Goat ovaries were collected from an abattoir and pieces of ovarian tissues were cultured for one or seven days in a supplemented alpha Minimum Essential Medium, alone or containing TGF-β (1, 5, 10 or 50ng/mL). Ovarian tissues from the fresh control as well as those cultured were processed for histological and ultrastructural studies. The results showed that when compared with fresh control, there was decrease in the percentages of histologically normal follicles in all treatments only after seven days culture. TGF-β did not affect the activation of preantral follicles regardless of its concentration, however, larger follicles diameter (P<0.05) was observed using 10ng/mL TGF-β than in the fresh control and other treatments. Moreover, this concentration maintained the normal ultrastructure after seven days of culture. In conclusion, TGF-β showed additional effect on the follicle growth and the maintenance of ultrastructural integrity of goat preantral follicles enclosed in ovarian tissue when used at 10ng/mL during seven days of culture
Decomposition and nutrient release of leguminous plants in coffee agroforestry systems.
Leguminous plants used as green manure are an important nutrient source for coffee plantations, especially for soils with low nutrient levels. Field experiments were conducted in the Zona da Mata of Minas Gerais State, Brazil to evaluate the decomposition and nutrient release rates of four leguminous species used as green manures (Arachis pintoi, Calopogonium mucunoides, Stizolobium aterrimum and
Stylosanthes guianensis) in a coffee agroforestry system under two different climate conditions. The initial N contents in plant residues varied from 25.7 to 37.0 g kg-1 and P from 2.4 to 3.0 g kg-1. The lignin/N, lignin/polyphenol and(lignin+polyphenol)/N ratios were low in all residues studied. Mass loss rates were highest in the first 15 days, when 25 % of the residues were decomposed. From 15 to 30 days, the decomposition rate decreased on both farms. On the farm in Pedra Dourada (PD), the decomposition constant k increased in the order C. mucunoides < S. aterrimum < S. guianensis < A. pintoi. On the farm in Araponga (ARA), there was no difference in the decomposition rate among leguminous plants. The N release rates varied from 0.0036 to 0.0096 d-1. Around 32 % of the total N content in the plant material was released in the first 15 days. In ARA, the N concentration in the S. aterrimum residues was always significantly higher than in the other residues. At the end of 360 days, the N released was 78 % in ARA and 89 % in PD of the initial content. Phosphorus was the most rapidly released nutrient (k values from 0.0165 to 0.0394 d-1). Residue decomposition and nutrient release did not correlate with initial residue chemistry and biochemistry, but differences in climatic conditions between the two study sites modified the decomposition rate constants
Constraining scalar fields with stellar kinematics and collisional dark matter
The existence and detection of scalar fields could provide solutions to
long-standing puzzles about the nature of dark matter, the dark compact objects
at the centre of most galaxies, and other phenomena. Yet, self-interacting
scalar fields are very poorly constrained by astronomical observations, leading
to great uncertainties in estimates of the mass and the
self-interacting coupling constant of these fields. To counter this,
we have systematically employed available astronomical observations to develop
new constraints, considerably restricting this parameter space. In particular,
by exploiting precise observations of stellar dynamics at the centre of our
Galaxy and assuming that these dynamics can be explained by a single boson
star, we determine an upper limit for the boson star compactness and impose
significant limits on the values of the properties of possible scalar fields.
Requiring the scalar field particle to follow a collisional dark matter model
further narrows these constraints. Most importantly, we find that if a scalar
dark matter particle does exist, then it cannot account for both the
dark-matter halos and the existence of dark compact objects in galactic nucleiComment: 23 pages, 8 figures; accepted for publication by JCAP after minor
change
Chaotic Diffusion on Periodic Orbits: The Perturbed Arnol'd Cat Map
Chaotic diffusion on periodic orbits (POs) is studied for the perturbed
Arnol'd cat map on a cylinder, in a range of perturbation parameters
corresponding to an extended structural-stability regime of the system on the
torus. The diffusion coefficient is calculated using the following PO formulas:
(a) The curvature expansion of the Ruelle zeta function. (b) The average of the
PO winding-number squared, , weighted by a stability factor. (c) The
uniform (nonweighted) average of . The results from formulas (a) and (b)
agree very well with those obtained by standard methods, for all the
perturbation parameters considered. Formula (c) gives reasonably accurate
results for sufficiently small parameters corresponding also to cases of a
considerably nonuniform hyperbolicity. This is due to {\em uniformity sum
rules} satisfied by the PO Lyapunov eigenvalues at {\em fixed} . These sum
rules follow from general arguments and are supported by much numerical
evidence.Comment: 6 Tables, 2 Figures (postscript); To appear in Physical Review
Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization.
The use of green manure may contribute to reduce soil erosion and increase the soil organic matter content and N availability in coffee plantations in the Zona da Mata, State of Minas Gerais, in Southeastern Brazil. The potential of four legumes (A. pintoi, C. mucunoides, S. aterrimum and S. guianensis)to produce above-ground
biomass, accumulate nutrients and mineralize N was studied in two coffee plantations of subsistence farmers under different climate conditions. The biomass production of C. mucunoides was influenced by the shade of the coffee plantation.C. mucunoides tended to mineralize more N than the other legumes due to the low polyphenol content and polyphenol/N ratio. In the first year, the crop establishment of A. pintoi in the area took longer than of the other legumes, resulting in lower biomass production and N2 fixation. In the long term, cellulose was the main
factor controlling N mineralization. The biochemical characteristics, nutrient accumulation and biomass production of the legumes were greatly influenced by
the altitude and position of the area relative to the sun
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