946 resultados para RESIDENCE TIME DISTRIBUTION
Resumo:
Microtubule-associated proteins (MAPs) are essential components necessary for the early growth process of axons and dendrites, and for the structural organization within cells. Both MAP2 and MAP5 are involved in these events, MAP2 occupying a role predominantly in dendrites, and MAP5 being involved in both axonal and dendritic growth. In the chick dorsal root ganglia, pseudo-unipolar sensory neurons have a T-shaped axon and are devoid of any dendrites. Therefore, they offer an ideal model to study the differential expression of MAPs during DRG development, specifically during axonal growth. In this study we have analyzed the expression and localization of MAP2 and MAP5 isoforms during chick dorsal root ganglia development in vivo, and in cell culture. In DRG, both MAPs appeared as early as E5. MAP2 consists of the 3 isoforms MAP2a, b and c. On blots, no MAP2a could be found at any stage. MAP2b increased between E6 and E10 and thereafter diminished slowly in concentration, while MAP2c was found between stages E6 and E10 in DRG. By immunocytochemistry, MAP2 isoforms were mainly located in the neuronal perikarya and in the proximal portion of axons, but could not be localized to distal axonal segments, nor in sciatic nerve at any developmental stage. On blots, MAP5 was present in two isoforms, MAP5a and MAP5b. The concentration of MAP5a was highest at E6 and then decreased to a low level at E18. In contrast, MAP5b increased between E6 and E10, and rapidly decreased after E14. Only MAP5a was present in sciatic nerve up to E14. Immunocytochemistry revealed that MAP5 was localized mainly in axons, although neuronal perikarya exhibited a faint immunostaining. Strong staining of axons was observed between E10 and E14, at a time coincidental to a period of intense axonal outgrowth. After E14 immunolabeling of MAP5 decreased abruptly. In DRG culture, MAP2 was found exclusively in the neuronal perikarya and the most proximal neurite segment. In contrast, MAP5 was detected in the neuronal cell bodies and all along their neurites. In conclusion, MAP2 seems involved in the early establishment of the cytoarchitecture of cell bodies and the proximal axon segment of somatosensory neurons, while MAP5 is clearly related to axonal growth.
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We assessed the distribution of Trypanosoma cruzi infection in peridomestic triatomines collected manually at a district-wide scale in rural villages around Olta, Western Argentina, and typed the isolated strains according to their pathogenicity to laboratory mice. Of 1623 triatomines examined, only 14 (0.9%) were infected with T. cruzi based on microscopical examination of feces. The prevalence of T. cruzi infection was 0.8% in Triatoma infestans, 2.3% in T. guasayana, and nil in T. garciabesi, T. platensis, and T. eratyrusiformis. Local transmission occurred in kitchens, store-rooms and goat corrals or nearby, though at very low levels. T. cruzi was detected by at least one parasitological method in 11 (79%) of 14 microscope-positive bugs. Hemoculture was the most sensitive method (67%) followed by culture of organ homogenates, histopathology or xenodiagnosis of inoculated suckling mice (55-58%), and culture of microscope-positive bug feces (46%). The evidence suggests that most of the isolated T. cruzi strains would be myotropic type III. Our study establishes for the first time that peridomestic, microscope-positive T. guasayana nymphs were actually infected with T. cruzi, and may be implicated as a putative secondary vector of T. cruzi in domestic or peridomestic sites.
Resumo:
Las Lomitas, Formosa, Argentina, reported 96 cases of tegumentary leishmaniasis during 2002. The urban transmission was suggested although previous outbreaks were related with floods of the Bermejo river (BR) 50 km from the village. Phlebotomine collections were performed during March 2002 to define the spatial distribution of risk, together with satellite imaginery. The phlebotomine/trap obtained was 1679.5 in the southern BR shore, 1.1 in the periruban-rural environment and 2.3 in the northern Pilcomayo river marshes. Lutzomyia neivai was the prevalent species (91.1%) among the 2393 phlebotomine captured, and it was only found in the BR traps. The other species were L. migonei (7.9%), L. cortelezzii (0.9%), and Brumptomyia guimaraesi (0.1%). The satellite images analysis indicates that the fishing spots at the BR were significantlyoverflowed during the transmission peak, consistent with fishermen recollections. This spatial restricted flood might concentrate vectors, reservoirs, and humans in high places. Therefore, both the spatial distribution of vectors and the sensor remoting data suggests that in Las Lomitas area the higher transmission risk it is still related with the gallery forest of the BR, despite of the urban residence of the cases. The surveillance and control implications of these results are discussed.
Resumo:
Protection from reactivation of persistent herpes virus infection is mediated by Ag-specific CD8 T cell responses, which are highly regulated by still poorly understood mechanisms. In this study, we analyzed differentiation and clonotypic dynamics of EBV- and CMV-specific T cells from healthy adults. Although these T lymphocytes included all subsets, from early-differentiated (EM/CD28(pos)) to late-differentiated (EMRA/CD28(neg)) stages, they varied in the sizes/proportions of these subsets. In-depth clonal composition analyses revealed TCR repertoires, which were highly restricted for CMV- and relatively diverse for EBV-specific cells. Virtually all virus-specific clonotypes identified in the EMRA/CD28(neg) subset were also found within the pool of less differentiated "memory" cells. However, striking differences in the patterns of dominance were observed among these subsets, because some clonotypes were selected with differentiation while others were not. Late-differentiated CMV-specific clonotypes were mostly characterized by TCR with lower dependency on CD8 coreceptor interaction. Yet all clonotypes displayed similar functional avidities, suggesting a compensatory role of CD8 in the clonotypes of lower TCR avidity. Importantly, clonotype selection and composition of each virus-specific subset upon differentiation was highly preserved over time, with the presence of the same dominant clonotypes at specific differentiation stages within a period of 4 years. Remarkably, clonotypic distribution was stable not only in late-differentiated but also in less-differentiated T cell subsets. Thus, T cell clonotypes segregate with differentiation, but the clonal composition once established is kept constant for at least several years. These findings reveal novel features of the highly sophisticated control of steady state protective T cell activity in healthy adults.
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Urbanization and vector domestication are currently proposed as factors that contributed to the recent increase of American cutaneous leishmaniasis (ACL). Is likely also urban transmission? Oran is the main city in the Argentinean hyper-endemic area of ACL, and human cases in urban residences are usually reported. In order to assess the spatial distribution of risk, phlebotomine traps were located in different environments of Oran. A total of 7,787 sand flies were captured: Lutzomyia neivai (98.1%), Lutzomyia migonei (1.2%), Lutzomyia cortelezzii (0.7%), and one Lutzomyia shannoni. During the season of transmission (April-May) a single sand fly was obtained in one out of five urban sites, while a trap in a peri-urban pigsty captured up to 2,985 Lu. neivai/night. Captures performed in the other season of vector activity (September-October) revealed that small-scale changes in the pigsty environment resulted in noticeable changes in the abundance of Lu. neivai. In addition, in a new neighbourhood, on the fringe of the city, 1,073 Lu. neivai/site were captured in the forested edge but one in the yard of the houses. Therefore, in this urban ACL focus the human-vector effective contact risk is still associated with peri-urban vegetation and ecotone modifications despite the urban residence of the cases.
Resumo:
Reaching and educating the masses to the benefit of all of mankind is the ultimate goal and through the use of this technology facility/tool many can be reached in their own language, in their own community, in their own time and at their own pace. Making this content available to those who will benefit from the information, is vital. These people who want to consume the content are not necessarily that interested in the qualification, they need the information. Making the content available in an auditory format may also help those who may not be as literate as others. The uses of audio/ recorded lessons have a number of uses and should not just be seen as a medium for content distribution to distant communities. Recording lectures makes it possible for a lecturer to present lectures to a vast number of students, while just presenting the lecture once.
Resumo:
Chromatographic separation of highly polar basic drugs with ideal ionspray mass spectrometry volatile mobile phases is a difficult challenge. A new quantification procedure was developed using hydrophilic interaction chromatography-mass spectrometry with turbo-ionspray ionization in the positive mode. After addition of deuterated internal standards and simple clean-up liquid extraction, the dried extracts were reconstituted in 500 microL pure acetonitrile and 5 microL was directly injected onto a Waters Atlantis HILIC 150- x 2.1-mm, 3-microm column. Chromatographic separations of cocaine, seven metabolites, and anhydroecgonine were obtained by linear gradient-elution with decreasing high concentrations of acetonitrile (80-56% in 18 min). This high proportion of organic solvent makes it easier to be coupled with MS. The eluent was buffered with 2 mM ammonium acetate at pH 4.5. Except for m-hydroxy-benzoylecgonine, the within-day and between-day precisions at 20, 100, and 500 ng/mL were below 7 and 19.1%, respectively. Accuracy was also below +/- 13.5% at all tested concentrations. The limit of quantification was 5 ng/mL (%Diff < 16.1, %RSD < 4.3) and the limit of detection below 0.5 ng/mL. This method was successfully applied to a fatal overdose. In Switzerland, cocaine abuse has dramatically increased in the last few years. A 45-year-old man, a known HIV-positive drug user, was found dead at home. According to relatives, cocaine was self-injected about 10 times during the evening before death. A low amount of cocaine (0.45 mg) was detected in the bloody fluid taken from a syringe discovered near the corpse. Besides injection marks, no significant lesions were detected during the forensic autopsy. Toxicological investigations showed high cocaine concentrations in all body fluids and tissues. The peripheral blood concentrations of cocaine, benzoylecgonine, and methylecgonine were 5.0, 10.4, and 4.1 mg/L, respectively. The brain concentrations of cocaine, benzoylecgonine, and methylecgonine were 21.2, 3.8, and 3.3 mg/kg, respectively. The highest concentrations of norcocaine (about 1 mg/L) were measured in bile and urine. Very high levels of cocaine were determined in hair (160 ng/mg), indicating chronic cocaine use. A low concentration of anhydroecgonine methylester was also found in urine (0.65 mg/L) suggesting recent cocaine inhalation. Therapeutic blood concentrations of fluoxetine (0.15 mg/L) and buprenorphine (0.1 microg/L) were also discovered. A relatively high concentration of Delta(9)-THC was measured both in peripheral blood (8.2 microg/L) and brain cortex (13.5 microg/kg), suggesting that the victim was under the influence of cannabis at the time of death. In addition, fluoxetine might have enhanced the toxic effects of cocaine because of its weak pro-arrhythmogenic properties. Likewise, combination of cannabinoids and cocaine might have increase detrimental cardiovascular effects. Altogether, these results indicate a lethal cocaine overdose with a minor contribution of fluoxetine and cannabinoids.
Resumo:
Niche conservatism, the tendency of a species niche to remain unchanged over time, is often assumed when discussing, explaining or predicting biogeographical patterns. Unfortunately, there has been no basis for predicting niche dynamics over relevant timescales, from tens to a few hundreds of years. The recent application of species distribution models (SDMs) and phylogenetic methods to analysis of niche characteristics has provided insight to niche dynamics. Niche shifts and conservatism have both occurred within the last 100 years, with recent speciation events, and deep within clades of species. There is increasing evidence that coordinated application of these methods can help to identify species which likely fulfill one key assumption in the predictive application of SDMs: an unchanging niche. This will improve confidence in SDM-based predictions of the impacts of climate change and species invasions on species distributions and biodiversity.
Resumo:
The study was undertaken in eight endemic districts of Orissa, India, to find the members of the species complexes of Anopheles culicifacies and Anopheles fluviatilis and their distribution patterns. The study area included six forested districts (Keonjhar, Angul, Dhenkanal, Ganjam, Nayagarh and Khurda) and two non-forested coastal districts (Puri and Jagatsingpur) studied over a period of two years (June 2007-May 2009). An. culicifacies A, B, C and D and An. fluviatilis S and T sibling species were reported. The prevalence of An. culicifacies A ranged from 4.2-8.41%, B from 54.96-76.92%, C from 23.08-33.62% and D from 1.85-5.94% (D was reported for the first time in Orissa, except for occurrences in the Khurda and Nayagarh districts). The anthropophilic indices (AI) were 3.2-4.8%, 0.5-1.7%, 0.7-1.37% and 0.91-1.35% for A, B, C and D, respectively, whereas the sporozoite rates (SR) were 0.49-0.54%, 0%, 0.28-0.37% and 0.41-0.46% for A, B, C and D, respectively. An. fluviatilis showed a similarly varied distribution pattern in which S was predominant (84.3% overall); its AI and SR values ranged from 60.7-90.4% and 1.2-2.32%, respectively. The study observed that the co-existence of potential vector sibling species of An. culicifacies (A, C and D) and An. fluviatilis S (> 50%) was responsible for the high endemicity of malaria in forested districts such as Dhenkanal, Keonjhar, Angul, Ganjam, Nayagarh and Khurda (> 5% slide positivity rate). Thus, the epidemiological scenario for malaria is dependent on the distribution of the vector sibling species and their vectorial capacity.
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This study aimed to compare foot plantar pressure distribution while jogging and running in highly trained adolescent runners. Eleven participants performed two constant-velocity running trials either at jogging (11.2 ± 0.9 km/h) or running (17.8 ± 1.4 km/h) pace on a treadmill. Contact area (CA in cm(2)), maximum force (F(max) in N), peak pressure (PP in kPa), contact time (CT in ms), and relative load (force time integral in each individual region divided by the force time integral for the total plantar foot surface, in %) were measured in nine regions of the right foot using an in-shoe plantar pressure device. Under the whole foot, CA, F(max) and PP were lower in jogging than in running (-1.2% [p<0.05], -12.3% [p<0.001] and -15.1% [p<0.01] respectively) whereas CT was higher (+20.1%; p<0.001). Interestingly, we found an increase in relative load under the medial and central forefoot regions while jogging (+6.7% and +3.7%, respectively; [p<0.05]), while the relative load under the lesser toes (-8.4%; p<0.05) was reduced. In order to prevent overloading of the metatarsals in adolescent runners, excessive mileage at jogging pace should be avoided.
Generation of cell polarity in plants links endocytosis, auxin distribution and cell fate decisions.
Resumo:
Dynamically polarized membrane proteins define different cell boundaries and have an important role in intercellular communication-a vital feature of multicellular development. Efflux carriers for the signalling molecule auxin from the PIN family are landmarks of cell polarity in plants and have a crucial involvement in auxin distribution-dependent development including embryo patterning, organogenesis and tropisms. Polar PIN localization determines the direction of intercellular auxin flow, yet the mechanisms generating PIN polarity remain unclear. Here we identify an endocytosis-dependent mechanism of PIN polarity generation and analyse its developmental implications. Real-time PIN tracking showed that after synthesis, PINs are initially delivered to the plasma membrane in a non-polar manner and their polarity is established by subsequent endocytic recycling. Interference with PIN endocytosis either by auxin or by manipulation of the Arabidopsis Rab5 GTPase pathway prevents PIN polarization. Failure of PIN polarization transiently alters asymmetric auxin distribution during embryogenesis and increases the local auxin response in apical embryo regions. This results in ectopic expression of auxin pathway-associated root-forming master regulators in embryonic leaves and promotes homeotic transformation of leaves to roots. Our results indicate a two-step mechanism for the generation of PIN polar localization and the essential role of endocytosis in this process. It also highlights the link between endocytosis-dependent polarity of individual cells and auxin distribution-dependent cell fate establishment for multicellular patterning.
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In 2004, Aedes (Stegomyia) albopictus (Skuse, 1894) was observed for the first time in Catalonia, northeastern Spain. A decade later, it has spread throughout the eastern Mediterranean region of the country and the Balearic Islands. Framed within a national surveillance project, we present the results of monitoring in 2013 in the autonomous communities of the mainland Levante. The current study reveals a remarkable increase in the spread of the invasive mosquito in relation to results from 2012; the species was present and well-established in 48 municipalities, most of which were along the Mediterranean coastline from the Valencian Community to the Region of Murcia.
Resumo:
The geographical distribution of Aedes albopictus in Brazil was updated according to the data recorded across the country over the last eight years. Countrywide house indexes (HI) for Ae. albopictus in urban and suburban areas were described for the first time using a sample of Brazilian municipalities. This mosquito is currently present in at least 59% of the Brazilian municipalities and in 24 of the 27 federal units (i.e., 26 states and the Federal District). In 34 Brazilian municipalities, the HI values for Ae. albopictus were higher than those recorded for Ae. aegypti, reaching figures as high as HI = 7.72 in the Southeast Region. Remarks regarding the current range of this mosquito species in the Americas are also presented. Nineteen American countries are currently infested and few mainland American countries have not confirmed the occurrence of Ae. albopictus. The large distribution and high frequency of Ae. albopictus in the Americas may become a critical factor in the spread of arboviruses like chikungunya in the new world.
Resumo:
This paper focuses on one of the methods for bandwidth allocation in an ATM network: the convolution approach. The convolution approach permits an accurate study of the system load in statistical terms by accumulated calculations, since probabilistic results of the bandwidth allocation can be obtained. Nevertheless, the convolution approach has a high cost in terms of calculation and storage requirements. This aspect makes real-time calculations difficult, so many authors do not consider this approach. With the aim of reducing the cost we propose to use the multinomial distribution function: the enhanced convolution approach (ECA). This permits direct computation of the associated probabilities of the instantaneous bandwidth requirements and makes a simple deconvolution process possible. The ECA is used in connection acceptance control, and some results are presented
Resumo:
The space subdivision in cells resulting from a process of random nucleation and growth is a subject of interest in many scientific fields. In this paper, we deduce the expected value and variance of these distributions while assuming that the space subdivision process is in accordance with the premises of the Kolmogorov-Johnson-Mehl-Avrami model. We have not imposed restrictions on the time dependency of nucleation and growth rates. We have also developed an approximate analytical cell size probability density function. Finally, we have applied our approach to the distributions resulting from solid phase crystallization under isochronal heating conditions