109 research outputs found
Experimental measurement of particle size effects on the self-heating ignition of biomass piles: Homogeneous samples of dust and pellets
Biomass can become an important fuel source for future power generation worldwide. However biomass piles are prone to self-heating and can lead to fire. When storing and transporting biomass, it is usually in the form of pellets which vary in diameter but are on average in the order of 7 mm. However, pellets tend to break up into smaller particles and into dust down to the µm size. For self-heating, size of particles is known to matter but the topic is poorly studied for biomass piles. This work presents an experimental study on the self-heating ignition behaviour of different particle sizes of wheat biomass. We study for the first time homogeneous samples from the dust scale to pellet diameter size, ranging from diameters of 300 µm to 6.5 mm. Experiments are done in an isothermal oven to find minimum ignition temperatures as a function of sample volume. The results are analysed using Frank-Kamenetskii theory. For the homogeneous biomass samples studied, we show that particle diameter variation does not bring a large change in self-heating ignition behaviour. The present work can be used to help quantify size effects on biomass ignition and help address the safety problems of biomass fires
Phylogenetic and time-scale analysis of dengue virus types 1 and 4 circulating in Puerto Rico and Key West, Florida, during 2010 epidemics
Electroexcitation of the at low momentum transfer
We report on new p measurements at the
resonance at the low momentum transfer region. The mesonic
cloud dynamics is predicted to be dominant and rapidly changing in this
kinematic region offering a test bed for chiral effective field theory
calculations. The new data explore the low dependence of the resonant
quadrupole amplitudes while extending the measurements of the Coulomb
quadrupole amplitude to the lowest momentum transfer ever reached. The results
disagree with predictions of constituent quark models and are in reasonable
agreement with dynamical calculations that include pion cloud effects, chiral
effective field theory and lattice calculations. The reported measurements
suggest that improvement is required to the theoretical calculations and
provide valuable input that will allow their refinements
Trypanosoma (Herpetosoma) rangeli Tejera, 1920: intracellular amastigote stages of reproduction in white mice
Genetic diversity and phylogenetic relationships of coevolving symbiont-harboring insect trypanosomatids, and their neotropical dispersal by invader African blowflies (Calliphoridae)
This study is about the inter- and intra-specific genetic diversity of trypanosomatids of
the genus Angomonas, and their association with Calliphoridae (blowflies) in Neotropical
and Afrotropical regions. Microscopic examination of 3,900 flies of various families,
mostly Calliphoridae, revealed that 31% of them harbored trypanosomatids. Small
subunit rRNA (SSU rRNA) barcoding showed that Angomonas predominated (46%)
over the other common trypanosomatids of blowflies of genera Herpetomonas and
Wallacemonas. Among Angomonas spp., A. deanei was much more common than
the two-other species, A. desouzai and A. ambiguus. Phylogenetic analyses based
on SSU rRNA, glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH)
and internal transcribed spacer rDNA (ITS rDNA) sequences revealed a marked
genetic diversity within A. deanei, which comprised four infraspecific genotypes (Dea1–
Dea4), and four corresponding symbiont genotypes (Kcr1–Kcr4). Host and symbiont
phylogenies were highly congruent corroborating their co-divergence, consistent with
host-symbiont interdependent metabolism and symbiont reduced genomes shaped by
a long coevolutionary history. We compared the diversity of Angomonas/symbionts from
three genera of blowflies, Lucilia, Chrysomya and Cochliomyia. A. deanei, A. desouzai,
and A. ambiguus were found in the three genera of blowflies in South America. In Africa,
A. deanei and A. ambiguus were identified in Chrysomya. The absence of A. desouzai
in Africa and its presence in Neotropical Cochliomyia and Lucilia suggests parasite
spillback of A. desouzai into Chrysomya, which was most likely introduced four decades
ago from Africa into the Neotropic. The absence of correlation between parasite diversity
and geographic and genetic distances, with identical genotypes of A. deanei found in the Neotropic and Afrotropic, is consistent with disjunct distribution due to the recent
human-mediated transoceanic dispersal of Angomonas by Chrysomya. This study
provides the most comprehensive data gathered so far on the genetic repertoires of
a genus of trypanosomatids found in flies from a wide geographical range.The PROAFRICA, INCT-EPIAMO,
and PROSUL programs of CNPq, PNIPB of Capes, and FAPESP
(Process 2016/07487-0). CAPEs (PNPD) granted a postdoctoral
scholarship to TB.http://www.frontiersin.org/Microbiologyam2018Veterinary Tropical Disease
Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli
Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts. Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins. Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets
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Multiphase phenomena in Diesel fuel injection systems
Fuel Injection Equipment (FIE) are an integral component of modern Internal Combustion Engines (ICE), since they play a crucial role in the fuel atomization process and in the formation of a fuel/air combustible mixture, consequently affecting efficiency and pollutant formation. Advancements and improvements of FIE systems are determined by the complexity of the physical mechanisms taking place; the spatial scales are in the order of millimetres, flow may become locally highly supersonic, leading to very small temporal scales of microseconds or less. The operation of these devices is highly unsteady, involving moving geometries such as needle valves. Additionally, extreme pressure changes imply that many assumptions of traditional fluid mechanics, such as incompressibility, are no longer valid. Furthermore, the description of the fuel properties becomes an issue, since fuel databases are scarce or limited to pure components, whereas actual fuels are commonly hydrocarbon mixtures. Last but not least, complicated phenomena such as phase change or transition from subcritical to transcritical/supercritical state of matter further pose complications in the understanding of the operation of these devices
Clinical Outcomes of Thirteen Patients with Acute Chagas Disease Acquired through Oral Transmission from Two Urban Outbreaks in Northeastern Brazil
Chagas disease is caused by a parasitic protozoan transmitted to humans by the contaminated feces of blood-feeding assassin bugs from the Triatominae subfamily. It may also be transmitted from mother to baby during pregnancy, by breastfeeding, blood transfusion or organ transplant. In rare cases, the disease can also be caused by accidental ingestion of contaminated food (sugar cane or açaí juice, drinking water, etc.). Acute Chagas disease often presents itself as a mononucleosis-like syndrome, with symptoms including fever, lymph node enlargement and muscle pain. The mortality rate of acute Chagas disease is high, mainly due to heart failure as a consequence of cardiac fiber lesions. There are few studies describing clinical outcomes and the disease progression of patients who receive therapeutic treatment, especially with regard to cardiac exam findings. In this report, the authors describe clinical findings from two micro-outbreaks occurring in impoverished towns in northeastern Brazil. Prior to receiving treatment, patient mortality rate was 28.6% in one of the outbreaks, and one pregnant woman experienced a spontaneous abortion due to the disease in the other outbreak. Most patients complained of fever, dyspnea, myalgia and periorbital edema. After receiving a two-month course of treatment, clinical symptoms improved and the number of abnormalities in cardiac exams decreased
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