1,070 research outputs found
Emergence of Hierarchy on a Network of Complementary Agents
Complementarity is one of the main features underlying the interactions in
biological and biochemical systems. Inspired by those systems we propose a
model for the dynamical evolution of a system composed by agents that interact
due to their complementary attributes rather than their similarities. Each
agent is represented by a bit-string and has an activity associated to it; the
coupling among complementary peers depends on their activity. The connectivity
of the system changes in time respecting the constraint of complementarity. We
observe the formation of a network of active agents whose stability depends on
the rate at which activity diffuses in the system. The model exhibits a
non-equilibrium phase transition between the ordered phase, where a stable
network is generated, and a disordered phase characterized by the absence of
correlation among the agents. The ordered phase exhibits multi-modal
distributions of connectivity and activity, indicating a hierarchy of
interaction among different populations characterized by different degrees of
activity. This model may be used to study the hierarchy observed in social
organizations as well as in business and other networks.Comment: 13 pages, 4 figures, submitte
Diffraction and an infrared finite gluon propagator
We discuss some phenomenological applications of an infrared finite gluon
propagator characterized by a dynamically generated gluon mass. In particular
we compute the effect of the dynamical gluon mass on and
diffractive scattering. We also show how the data on photoproduction
and hadronic reactions can be derived from the and
forward scattering amplitudes by assuming vector meson dominance and
the additive quark model.Comment: 4 pages, 7 figures, added references and figures, changed structure.
Contribution to Proceedings of XVIIIth Reuniao de Trabalho sobre Interacoes
Hadronicas, Sao Paulo, Brazil, 22-24 May, 200
A Study For Efficiently Solving Optimisation Problems With An Increasing Number Of Design Variables
Coupling optimisation algorithms to Finite Element Methods (FEM) is a very promising way to achieve optimal metal forming processes. However, many optimisation algorithms exist and it is not clear which of these algorithms to use. This paper investigates the sensitivity of a Sequential Approximate Optimisation algorithm (SAO) proposed in [1-4] to an increasing number of design variables and compares it with two other algorithms: an Evolutionary Strategy (ES) and an Evolutionary version of the SAO (ESAO). In addition, it observes the influence of different Designs Of Experiments used with the SAO. It is concluded that the SAO is very capable and efficient and its combination with an ES is not beneficial. Moreover, the use of SAO with Fractional Factorial Design is the most efficient method, rather than Full Factorial Design as proposed in [1-4]
Abcesso Hepático por Streptococcus Anginosus e Eikenella Corrodens, Secundário a Perfuração Gástrica por Espinha de Peixe
Introduction: Foreign-body ingestion is a common event, but in only less than 1% of the cases complications occur. Hepatic abscesses induced by foreign-body penetration are rare. To date, there are only 62 reported cases of hepatic abscess secondary to fish bone perforation of the gastrointestinal tract.
Case presentation: A 78-year-old male patient was admitted due to high fever and vomiting for 2 days, along with frequent eructations for the past 3 months. Abdominal ultrasound showed a liver abscess in the left lobe, and computed tomography revealed a hyperdense linear image that crossed the superior wall of the gastric antrum, contacting the liver lesion, suggestive of a foreign body, probably a fish bone. Blood cultures were positive with isolation of Streptococcus anginosus and Eikenella corrodens. Ultrasound-guided percutaneous drainage of the abscess was done, and S. anginosus was isolated in the pus. Surgical debridement and fish bone removal were performed; the patient completed 21 days of antibiotic therapy, with a favorable evolution.
Conclusion: To the best of our knowledge, this is the first reported case of liver abscess caused by fish bone penetration with isolation of S. anginosus and E. corrodens. Bacterial coaggregation is one of the mechanisms that can explain their ability for causing invasive infections away from the oral cavity, by increasing their resistance to the innate immune system and survival of both species.info:eu-repo/semantics/publishedVersio
Dirofilaria immitis antigenemia and microfilaremia in Iberian wolves and red foxes from Portugal
Background: Dirofilaria immitis is a parasitic nematode endemic in the Mediterranean countries, which causes cardiopulmonary dirofilariosis in wild and domestic animals. Despite being recognized hosts of D. immitis, wild carnivores such as wolves and foxes are frequently disregarded when considering a potential role in the transmission of these zoonotic nematodes. In Portugal, studies available regarding D. immitis circulation are scarce, likely underestimating its relevance. To add knowledge on this, we sought to assess Iberian wolves (Canis lupus signatus) and red foxes (Vulpes vulpes) from northern Portugal for D. immitis antigenemia and microfilaremia. Methods: Blood samples from 42 Iberian wolves and 19 red foxes were collected, during 2010–2012, in Peneda-Gerês National Park. Antigenemia was searched for by rapid antigen detection test kits (Uranotest Dirofilaria ®). Microfilaremia was assessed by polymerase chain reaction (PCR). Nucleic acids were extracted from blood using QIAamp® DNA Mini Kit (Qiagen), and DNA was screened for the presence of microfilaria using a conventional PCR targeting the 5.8S-internal transcribed spacer 2–28S regions, followed by bidirectional sequencing, Basic Local Alignment Search Tool analysis and phylogenetic analysis. Results: Three red foxes had antigenemia, with an occurrence of 15.8% (95% confidence interval [CI] 3.4–39.6), while showing no evidence for the presence of microfilaremia. No wolf samples presented evidence for D. immitis antigenemia. Nevertheless, two wolves were positive for D. immitis microfilaremia (4.8%; 95% CI 0.6–16.2%) as revealed by PCR and confirmed by bidirectional sequencing. Conclusions: Although Dirofilaria microfilaremia in wolves does not necessarily correlate to an endangerment of the infected animal's health, positive individuals can act as a reservoir for further infection if the intermediate mosquito hosts are present. To the best of our knowledge, one single study had reported that wolves were suitable Dirofilaria hosts, but microfilaremia have never been reported. Graphical Abstract: [Figure not available: see fulltext.] © 2022, The Author(s).Funding text 1: Publication of this paper has been sponsored by Elanco Animal Health in the framework of the 17th CVBD®World Forum Symposium.; Funding text 2: This work was supported by national funds, through Fundação para a Ciência e a Tecnologia (FCT, Portuguese Foundation for Science and Technology), under projects UIDB/04750/2020 and LA/P/0064/2020; and projects UIDB/CVT/00772/2020 and LA/P/0059/2020, also funded by FCT
Montado management effects on the abundance and conservation of reptiles in Alentejo, Southern Portugal
Abstract This study was carried out in the IberianMediterranean region of Alentejo (Southern Portugal) to discover which 'montado' management practices significantly affected reptile variables (abundance, richness). Field surveys on 30 sampling plots allowed us to identify 370 individuals distributed among 12 terrestrial reptile species (six lizards, one amphisbaenid and five colubrid snakes). The lizard Psammodromus algirus was the dominant species (n = 297 individuals). The highest species richness was comprised of five species, whilst two or three species were recorded in two-thirds of the sampling plots. Principal component analysis over management variables accounted for 71.8% of the total variance and subsequently helped to reveal four agrosilvopastoral types. Among them, the highest reptile abundance largely overlapped the cork oak montado, while higher cattle stocking rates were estimated (trampling index) to occur in the holm oak areas, affecting significantly the reptiles. Regression models also showed that both reptile abundance and richness were significantly related to montado areas, where the shrub layer is well preserved and cattle are either absent or present at low stocking rates. Adequate management of montado, preserving the shrub patchwork, is crucial for the conservation of reptiles. Livestock stocking rates should also be maintained at a sustainable level of 0.2-0.4 cattle/ha
Physicochemical characterization, microbiological quality and safety, and pharmacological potential of Hancornia speciosa Gomes
Hancornia speciosa Gomes is a fruit tree, commonly known as the mangaba tree, which is widespread throughout Brazil. The leaves
of this plant are used in traditional medicine for medicinal purposes. Thus, the objective of this study was to perform a
physicochemical characterization, identify the lipophilic antioxidants and fatty acids, and determine the microbiological quality
and safety of H. speciosa leaves. In addition, the antioxidant, antimutagenic, and inhibitory activities of the ethanolic extract of
H. speciosa leaves (EEHS) against enzymes related to neurodegenerative diseases, inflammation, obesity, and diabetes were
investigated. Furthermore, this study aimed at assessing the in vivo effects of the EEHS on the glycemia of normoglycemic and
diabetic Wistar rats. Physicochemical characterization was performed by colorimetry and gas-liquid chromatography with flame
ionization detection (GC-FID). The total number of colonies of aerobic mesophiles, molds, and yeasts was determined. The total
coliforms and Escherichia coli were counted using the SimPlates kit, and sulphite-reducing Clostridium spores were quantified
using the sulphite-polymyxin-sulfadiazine agar method. Salmonella spp. were detected using the 1-2 Test. The antioxidant activity
of the EEHS was measured by its inhibition of 2,2′-azobis(2-amidinopropane) dihydrochloride- (AAPH-) induced oxidative
hemolysis of human erythrocytes. The antimutagenic activity was determined using the Ames test. The acetylcholinesterase,
butyrylcholinesterase, tyrosinase, hyaluronidase, lipase, α-amylase, and α-glycosidase enzyme-inhibiting activities were assessed
and compared with commercial controls. The in vivo effects of the EEHS were assessed using the oral glucose tolerance test in
normoglycemic Wistar rats and measuring the blood glucose levels in diabetic rats. The results demonstrated physical-chemical
parameters of microbiological quality and safety in the leaves of H. speciosa, as well as antioxidant and antimutagenic activities
and inhibition of enzymes related to neurodegenerative diseases, inflammation, obesity, and diabetes. In in vivo assays, it was
shown that the normoglycemic rats challenged with glucose overload show significantly decreased blood glucose levels when
treated with the EEHS. Taken together, the results ensure the microbiological quality and safety as well as showing the contents of
carotenoids and polyunsaturated fatty acids of H. speciosa leaves. Additionally, the antioxidant, antimutagenic, anti-inflammatory,
anti-Alzheimer’s disease, anti-Parkinson’s disease, antiobesity, and antihyperglycemic activities of the EEHS were demonstrated.This work was supported by grants from Fundação de Apoio
ao Desenvolvimento do Ensino, Ciência e Tecnologia do
Estado de Mato Grosso do Sul (FUNDECT), Coordenação
de Aperfeiçoamento de Pessoal de Nível Superior (CAPES),
Conselho Nacional de Desenvolvimento Científico e Tecnológico
(CNPq), Universidade Federal da Grande Dourados
(UFGD), and PRODER (24.073–A, Portugal).info:eu-repo/semantics/publishedVersio
Morpho-anatomical characterization of mature embryo-derived callus of rice (Oryza sativa L.) suitable for transformation.
The objective of this study was to morphoanatomically characterize embryogenic rice calli during early induction of somatic embryogenesis of three Brazilian rice cultivars. Herein, we explored embryogenic units (EUs) from 2-week-old cut proliferated calli to verify whether they were suitable for Agrobacterium tumefasciens-mediated transformation. Histological analysis and scanning electron microscopy (SEM) were used to analyze these types of calli during early rice callogenesis in the cultivars BRS Primavera, BRS Bonança, and BRS Caiapó. The characteristics of the embryogenic cells were preserved in the EUs, which showed a globular, compact structure that contained tightly packed cells and thus rendered the cells suitable for transformation. The EUs of BRS Caiapó also maintained the characteristics of the nonembryogenic callus, such as an elongated morphology and a lack of cellular organization. In general, the observations of the histological sections corresponded with those of the SEM images. The histological analysis suggested that all cultivars used in these experiments have morphogenic potential. The EUs from proliferated 2-week-old cut calli maintained their embryogenic features. The EUs were subjected to Agrobacterium-mediated transformation, which exhibited a regeneration frequency of 58 % for transformed hygromycin-resistant cell lines. These results show that EUs from proliferated 2-week-old cut calli are suitable for plant transformation
Physical Interactions With Bacteria and Protozoan Parasites Establish the Scavenger Receptor SSC4D as a Broad-Spectrum Pattern Recognition Receptor
Since the pioneering discoveries, by the Nobel laureates Jules Hoffmann and Bruce Beutler, that Toll and Toll-like receptors can sense pathogenic microorganisms and initiate, in vertebrates and invertebrates, innate immune responses against microbial infections, many other families of pattern recognition receptors (PRRs) have been described. One of such receptor clusters is composed by, if not all, at least several members of the scavenger receptor cysteine-rich (SRCR) superfamily. Many SRCR proteins are plasma membrane receptors of immune cells; however, a small subset consists of secreted receptors that are therefore in circulation. We here describe the first characterization of biological and functional roles of the circulating human protein SSC4D, one of the least scrutinized members of the family. Within leukocyte populations, SSC4D was found to be expressed by monocytes/macrophages, neutrophils, and B cells, but its production was particularly evident in epithelial cells of several organs and tissues, namely, in the kidney, thyroid, lung, placenta, intestinal tract, and liver. Similar to other SRCR proteins, SSC4D shows the capacity of physically binding to different species of bacteria, and this opsonization can increase the phagocytic capacity of monocytes. Importantly, we have uncovered the capacity of SSC4D of binding to several protozoan parasites, a singular feature seldom described for PRRs in general and here demonstrated for the first time for an SRCR family member. Overall, our study is pioneer in assigning a PRR role to SSC4D.This work was funded by National Funds through FCT– Fundação para a Ciência e a Tecnologia, I.P., under the projects SRecognite Infect-ERA/0003/2015 and UIDB/04293/ 2020. Individual funding to JT was provided by FCT through CEECIND/02362/2017. MC, RS, and MS were recipients of studentships from FCT, respectively, SFRH/BD/116791/2016, SFRH/BD/110691/2015, and SFRH/BD/133485/2017.
This paper is dedicated to our colleague and friend Rui Appelberg (1960-2020). The authors acknowledge the support of the i3S Scientific Platform BioSciences Screening, member of the national infrastructure PPBI–Portuguese Platform of Bioimaging (PPBI-POCI-01-0145-FEDER-022122) and PT-OPENSCREEN. Tissue sections were kindly provided by Amaro Frutuoso, Department of Complementary Means of Diagnosis and Therapy, Service of Pathology, Hospital Pedro Hispano, Matosinhos
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