1,572 research outputs found
Quantum equivalence between the self-dual and the Maxwell-Chern-Simons models nonlinearly coupled to U(1) scalar fields
The use of master actions to prove duality at quantum level becomes
cumbersome if one of the dual fields interacts nonlinearly with other fields.
This is the case of the theory considered here consisting of U(1) scalar fields
coupled to a self-dual field through a linear and a quadratic term in the
self-dual field. Integrating perturbatively over the scalar fields and deriving
effective actions for the self-dual and the gauge field we are able to
consistently neglect awkward extra terms generated via master action and
establish quantum duality up to cubic terms in the coupling constant. The
duality holds for the partition function and some correlation functions. The
absence of ghosts imposes restrictions on the coupling with the scalar fields.Comment: 13 pages, no figure
Functional gallic acid-based dendrimers as synthetic nanotools to remodel amyloid-β-42 into noncytotoxic forms
The self-assembly of amyloid-β (Aβ) generates cytotoxic oligomers linked to the onset and progression of Alzheimer’s disease (AD). As many fundamental molecular pathways that control Aβ aggregation are yet to be unraveled, an important strategy to control Aβ cytotoxicity is the development of bioactive synthetic nanotools capable of interacting with the heterogeneous ensemble of Aβ species and remodel them into noncytotoxic forms. Herein, the synthesis of nanosized, functional gallic acid (Ga)-based dendrimers with a precise number of Ga at their surface is described. It is shown that these Ga-terminated dendrimers interact by H-bonding with monomeric/oligomeric Aβ species at their Glu, Ala, and Asp residues, promoting their remodeling into noncytotoxic aggregates in a process controlled by the Ga units. The multivalent presentation of Ga on the dendrimer surface enhances their ability to interact with Aβ, inhibiting the primary and secondary nucleation of Aβ fibrillization and disrupting the Aβ preformed fibrils.The authors acknowledge the financial support from the EC
(FORECAST-668983), “Programa Operacional Regional do
Norte”, “Fundo Social Europeu”, Norte2020 TERM&SC, for
the PhD grant NORTE-08-5369-FSE-000044, the Spanish Ministry of Science and Innovation (RTI2018-102212-B-I00),
the Xunta de Galicia (ED431C 2018/30; Centro singular de
investigación de Galicia accreditation 2019−2022, ED431G
2019/03), European Regional Development Fund-ERDF, and
the Galician Supercomputing Centre (CESGA) and the
MAT2016-80266-R of the Spanish Ministry of Science and
Innovation
Variabilidade geográfica da razão mortalidade/incidência por cancro da mama no sul da Europa
O cancro da mama é o segundo carcinoma mais frequente constituindo a principal causa de mortalidade por carcinoma em mulheres (Ferlay et al., 2013). Detecção e intervenção precoce e qualidade do tratamento influenciam a mortalidade por esta patologia (Bastos, Peleteiro, Gouveia, Coleman, & Lunet, 2010). A percentagem da razão de Mortalidade/Incidência (%RMI) avalia o acesso a rastreios e a qualidade das terapeuticas, apresentando valores baixos se a mortalidade é baixa para os casos incidentes reportados. (Sunkara & Hebert, 2015).
Objetivo: Avaliar a variabilidade na %RMI por cancro da mama (número de óbitos por cada 100 casos incidentes de cancro da mama) em quatro países do sul da Europa culturalmente próximos: Espanha, Portugal, Grécia e Itália. Metodologia: Através da International Agency for Research on Cancer (IARC), obtiveram-se casos observados em 2012 (incidentes e óbitos) para cada país em estudo em mulheres com 15-39, 40-49, 50-64, 65-74 e 75 ou mais anos (WHO, 2016). Obtiveram-se valores de %RMI por país e faixa etária dividindo o número de óbitos pelo número de casos incidentes e multiplicando por 100. Os respetivos intervalos de confiança a 95% (IC95%) foram obtidos pelo teste exato de Fisher.
Resultados: Considerando os quatro países como um todo, verifica-se que a %RMI para cancro da mama (número de óbitos por cada 100 casos incidentes) é de 8%, 12%, 17%, 24% e 55%, respectivamente em mulheres com 15-39, 40-49, 50-64, 65-74 e 75 ou mais anos. Verifica-se variabilidade entre países para este indicador, mas não em todas as faixas etárias. Para mulheres mais jovens, Portugal apresenta %RMI de 8,7% (IC95%:6,5-11,3) muito semelhante aos outros três países. Em mulheres com idades entre 40-49 anos e 50-64 anos a %RMI observada em Portugal é, respectivamente, 13,6% (IC95%:11,6-15,8) e 19,7% (IC95%:18,0-21,5), notoriamente inferior à observada na Grécia mas mais elevada em relação a Espanha e Itália. Em mulheres com 65-74 e 75 ou mais anos, as %RMI observadas em Portugal foram, respectivamente, 27,4% (IC95%:24,9-30,1) e 52,5% (IC95%:49,7-55,3), muito semelhantes ao que se observa em Espanha e Itália.
Conclusões: Embora em mulheres mais jovens o número de óbitos por cada 100 casos incidentes de cancro da mama seja inferior a 10, este valor é superior a 50 nas mulheres mais velhas. De acordo com os resultados há variabilidade geográfica na %RMI mas esta variabilidade não é transversal a todas as faixas etárias. Os resultados sugerem que o acesso a diagnóstico precoce e a efectividade de tratamento diferem entre países, mas que esta relação é modificada pela idade. Os resultados sugerem equacionar as estratégias preventivas adaptando-as às diferentes faixas etárias.info:eu-repo/semantics/publishedVersio
Development of stimuli-responsive graphene-based yolk-shell magnetic nanoparticles for controlled release of anticancer drugs
Magnetic drug delivery systems have attracted much attention in the last decades due to the possibility
to improve the therapeutic efficacy of anticancer drugs, by enabling instable and poorly soluble drug
agents to reach tumour cells after being guided by low magnetic fields and monitored by magnetic
resonance imaging (MRI) [1]. Hence, a lower amount of anticancer drug is needed and the typical side
effects of chemotherapy are minimized [2]. Commonly, these nanoparticles are designed with a
magnetic core coated with a metal or a non-metal structure, such as gold or silica. However, these
approaches present some drawbacks, such as low drug loading capacity and lack of stimuli-responsive
release. Alternatively, carbon-coated magnetic nanoparticles offer higher chemical and thermal stability,
larger surface area, biocompatibility and easier functionalization due to the high capacity of adsorption.
Moreover, these materials have shown great ability to be used as pH stimuli-responsive controlled
release platforms, due to the disruption of supramolecular interaction at acidic pH [3]. In this context,
graphene-coated yolk-shell magnetic nanoparticles – hybrid materials comprising a superparamagnetic
core coated by a graphene-based shell that covers a hollow region (i.e., Fe3O4@void@C), – were
developed as super-drug nanocarriers systems, exhibiting high loading contents of the anticancer drug
Doxorubicin due to the large cavity volume between the shell and the magnetic core, and a stimuliresponsive
controlled release in response to acidic environments (pH 5), such as those found in tumour
tissues. These results shed light on the development of new hybrid nanomaterials with high potential to
be applied in biomedical applications.info:eu-repo/semantics/publishedVersio
Multi-Instrumented Observations of the Equatorial F-Region During June Solstice: Large-Scale Wave Structures and Spread-F
Typical equatorial spread-F events are often said to occur during post-sunset, equinox conditions in most longitude sectors. Recent studies, however, have found an unexpected high occurrence of ionospheric F-region irregularities during June solstice, when conditions are believed to be unfavorable for the development of plasma instabilities responsible for equatorial spread-F (ESF). This study reports new results of a multi-instrumented investigation with the objective to better specify the occurrence of these atypical June solstice ESF in the American sector and better understand the conditions prior to their development. We present the first observations of June solstice ESF events over the Jicamarca Radio Observatory (11.95° S, 76.87° W, ∼ 1° dip latitude) made by a 14-panel version of the Advanced Modular Incoherent Scatter Radar system (AMISR-14). The observations were made between July 11 and August 4, 2016, under low solar flux conditions and in conjunction with dual-frequency GPS, airglow, and digisonde measurements. We found echoes occurring in the pre-, post-, and both pre- and post-midnight sectors. While at least some of these June solstice ESF events could have been attributed to disturbed electric fields, a few events also occurred during geomagnetically quiet conditions. The late appearance (22:00 LT or later) of three of the observed events, during clear-sky nights, provided a unique opportunity to investigate the equatorial bottomside F-region conditions, prior to ESF, using nighttime airglow measurements. We found that the airglow measurements (630 nm) made by a collocated all-sky camera show the occurrence of ionospheric bottomside F-region perturbations prior to the detection of ESF echoes in all three nights. The airglow fluctuations appear as early as 1 hour prior to radar echoes, grow in amplitude, and then coincide with ESF structures observed by AMISR-14 and GPS TEC measurements. They also show some of the features of the so-called large-scale wave structures (LSWS) that have been detected, previously, using other types of observations and have been suggested to be precursors of ESF. The bottomside fluctuations have zonal spacings between 300 and 500 km, are aligned with the magnetic meridian, and extend at least a few degrees in magnetic latitude
Unbiased Metagenomic Sequencing for Pediatric Meningitis in Bangladesh Reveals Neuroinvasive Chikungunya Virus Outbreak and Other Unrealized Pathogens.
The burden of meningitis in low-and-middle-income countries remains significant, but the infectious causes remain largely unknown, impeding institution of evidence-based treatment and prevention decisions. We conducted a validation and application study of unbiased metagenomic next-generation sequencing (mNGS) to elucidate etiologies of meningitis in Bangladesh. This RNA mNGS study was performed on cerebrospinal fluid (CSF) specimens from patients admitted in the largest pediatric hospital, a World Health Organization sentinel site, with known neurologic infections (n = 36), with idiopathic meningitis (n = 25), and with no infection (n = 30), and six environmental samples, collected between 2012 and 2018. We used the IDseq bioinformatics pipeline and machine learning to identify potentially pathogenic microbes, which we then confirmed orthogonally and followed up through phone/home visits. In samples with known etiology and without infections, there was 83% concordance between mNGS and conventional testing. In idiopathic cases, mNGS identified a potential bacterial or viral etiology in 40%. There were three instances of neuroinvasive Chikungunya virus (CHIKV), whose genomes were >99% identical to each other and to a Bangladeshi strain only previously recognized to cause febrile illness in 2017. CHIKV-specific qPCR of all remaining stored CSF samples from children who presented with idiopathic meningitis in 2017 (n = 472) revealed 17 additional CHIKV meningitis cases, exposing an unrecognized meningitis outbreak. Orthogonal molecular confirmation, case-based clinical data, and patient follow-up substantiated the findings. Case-control CSF mNGS surveys can complement conventional diagnostic methods to identify etiologies of meningitis, conduct surveillance, and predict outbreaks. The improved patient- and population-level data can inform evidence-based policy decisions.IMPORTANCE Globally, there are an estimated 10.6 million cases of meningitis and 288,000 deaths every year, with the vast majority occurring in low- and middle-income countries. In addition, many survivors suffer from long-term neurological sequelae. Most laboratories assay only for common bacterial etiologies using culture and directed PCR, and the majority of meningitis cases lack microbiological diagnoses, impeding institution of evidence-based treatment and prevention strategies. We report here the results of a validation and application study of using unbiased metagenomic sequencing to determine etiologies of idiopathic (of unknown cause) cases. This included CSF from patients with known neurologic infections, with idiopathic meningitis, and without infection admitted in the largest children's hospital of Bangladesh and environmental samples. Using mNGS and machine learning, we identified and confirmed an etiology (viral or bacterial) in 40% of idiopathic cases. We detected three instances of Chikungunya virus (CHIKV) that were >99% identical to each other and to a strain previously recognized to cause systemic illness only in 2017. CHIKV qPCR of all remaining stored 472 CSF samples from children who presented with idiopathic meningitis in 2017 at the same hospital uncovered an unrecognized CHIKV meningitis outbreak. CSF mNGS can complement conventional diagnostic methods to identify etiologies of meningitis, and the improved patient- and population-level data can inform better policy decisions
Impact of short-term temperature challenges on the larvicidal activities of the entomopathogenic watermold <i>Leptolegnia chapmanii</i> against <i>Aedes aegypti</i>, and development on infected dead larvae
The oomycete Leptolegnia chapmanii is among the most promising entomopathogens for biological control of Aedes aegypti. This mosquito vector breeds in small water collections, where this aquatic watermold pathogen can face short-term scenarios of challenging high or low temperatures during changing ambient conditions, but it is yet not well understood how extreme temperatures might affect the virulence and recycling capacities of this pathogen. We tested the effect of short-term exposure of encysted L. chapmanii zoospores (cysts) on A. aegypti larvae killed after infection by this pathogen to stressful low or high temperatures on virulence and production of cysts and oogonia, respectively. Cysts were exposed to temperature regimes between −12 °C and 40 °C for 4, 6 or 8 h, and then their infectivity was tested against third instar larvae (L3) at 25 °C; in addition, production of cysts and oogonia on L3 killed by infection exposed to the same temperature regimes as well as their larvicidal activity were monitored. Virulence of cysts to larvae and the degree of zoosporogenesis on dead larvae under laboratory conditions were highest at 25 °C but were hampered or even blocked after 4 up to 8 h exposure of cysts or dead larvae at both the highest (35 °C and 40 °C) and the lowest (−12 °C) temperatures followed by subsequent incubation at 25 °C. The virulence of cysts was less affected by accelerated than by slow thawing from the frozen state. The production of oogonia on dead larvae was stimulated by short-term exposure to freezing temperatures (−12 °C and 0 °C) or cool temperatures (5 °C and 10 °C) but was not detected at higher temperatures (25 °C–40 °C). These findings emphasize the susceptibility of L. chapmanii to short-term temperature stresses and underscore its interest as an agent for biocontrol of mosquitoes in the tropics and subtropics, especially A. aegypti, that breed preferentially in small volumes of water that are generally protected from direct sunlight.Centro de Estudios Parasitológicos y de Vectore
Impact of short-term temperature challenges on the larvicidal activities of the entomopathogenic watermold <i>Leptolegnia chapmanii</i> against <i>Aedes aegypti</i>, and development on infected dead larvae
The oomycete Leptolegnia chapmanii is among the most promising entomopathogens for biological control of Aedes aegypti. This mosquito vector breeds in small water collections, where this aquatic watermold pathogen can face short-term scenarios of challenging high or low temperatures during changing ambient conditions, but it is yet not well understood how extreme temperatures might affect the virulence and recycling capacities of this pathogen. We tested the effect of short-term exposure of encysted L. chapmanii zoospores (cysts) on A. aegypti larvae killed after infection by this pathogen to stressful low or high temperatures on virulence and production of cysts and oogonia, respectively. Cysts were exposed to temperature regimes between −12 °C and 40 °C for 4, 6 or 8 h, and then their infectivity was tested against third instar larvae (L3) at 25 °C; in addition, production of cysts and oogonia on L3 killed by infection exposed to the same temperature regimes as well as their larvicidal activity were monitored. Virulence of cysts to larvae and the degree of zoosporogenesis on dead larvae under laboratory conditions were highest at 25 °C but were hampered or even blocked after 4 up to 8 h exposure of cysts or dead larvae at both the highest (35 °C and 40 °C) and the lowest (−12 °C) temperatures followed by subsequent incubation at 25 °C. The virulence of cysts was less affected by accelerated than by slow thawing from the frozen state. The production of oogonia on dead larvae was stimulated by short-term exposure to freezing temperatures (−12 °C and 0 °C) or cool temperatures (5 °C and 10 °C) but was not detected at higher temperatures (25 °C–40 °C). These findings emphasize the susceptibility of L. chapmanii to short-term temperature stresses and underscore its interest as an agent for biocontrol of mosquitoes in the tropics and subtropics, especially A. aegypti, that breed preferentially in small volumes of water that are generally protected from direct sunlight.Centro de Estudios Parasitológicos y de Vectore
Absolute and Relative Reliability of the Assessment of the Muscle Mechanical Properties of Pelvic Floor Muscles in Women with and without Urinary Incontinence
An analysis of the muscle mechanical properties (MMPs) of the pelvic floor muscles (PFMs) is relevant for understanding the physiopathology of urinary incontinence (UI). However, there is no objective and reliable methodology currently available for quantifying the MMPs of PFMs. Thus, the objective was to determine the intra-rater and inter-rater reliability of the MMPs of PFM assessment with a hand-held tonometer device, called the MyotonPRO, in young women with and without UI. Sociodemographic and pelvic floor questionnaires, plus MMPs of PFMs were assessed in 38 nulliparous women with UI and 40 matched healthy women by two trained physiotherapists on two different occasions, 48–72 h apart. Good to excellent absolute reliability was found for tone, stiffness, and decrement of both intra- and inter-rater analyses in both study groups (Intraclass Correlation Coefficient ranged from 0.75 to 0.92), with a trend of lower values for relaxation and creep. The standard error of measurement (SEM) did not achieve 10% of the mean values for any MMPs. The minimum detectable change (MDC) values were also provided for clinical applications. In conclusion, the relative reliability of tone, stiffness, and the assessment of the decrement of PFMs with MyotonPRO is good to excellent for UI and healthy women. The SEM and MDC values were acceptable for their application in clinical settings
Impact of short-term temperature challenges on the larvicidal activities of the entomopathogenic watermold <i>Leptolegnia chapmanii</i> against <i>Aedes aegypti</i>, and development on infected dead larvae
The oomycete Leptolegnia chapmanii is among the most promising entomopathogens for biological control of Aedes aegypti. This mosquito vector breeds in small water collections, where this aquatic watermold pathogen can face short-term scenarios of challenging high or low temperatures during changing ambient conditions, but it is yet not well understood how extreme temperatures might affect the virulence and recycling capacities of this pathogen. We tested the effect of short-term exposure of encysted L. chapmanii zoospores (cysts) on A. aegypti larvae killed after infection by this pathogen to stressful low or high temperatures on virulence and production of cysts and oogonia, respectively. Cysts were exposed to temperature regimes between −12 °C and 40 °C for 4, 6 or 8 h, and then their infectivity was tested against third instar larvae (L3) at 25 °C; in addition, production of cysts and oogonia on L3 killed by infection exposed to the same temperature regimes as well as their larvicidal activity were monitored. Virulence of cysts to larvae and the degree of zoosporogenesis on dead larvae under laboratory conditions were highest at 25 °C but were hampered or even blocked after 4 up to 8 h exposure of cysts or dead larvae at both the highest (35 °C and 40 °C) and the lowest (−12 °C) temperatures followed by subsequent incubation at 25 °C. The virulence of cysts was less affected by accelerated than by slow thawing from the frozen state. The production of oogonia on dead larvae was stimulated by short-term exposure to freezing temperatures (−12 °C and 0 °C) or cool temperatures (5 °C and 10 °C) but was not detected at higher temperatures (25 °C–40 °C). These findings emphasize the susceptibility of L. chapmanii to short-term temperature stresses and underscore its interest as an agent for biocontrol of mosquitoes in the tropics and subtropics, especially A. aegypti, that breed preferentially in small volumes of water that are generally protected from direct sunlight.Centro de Estudios Parasitológicos y de Vectore
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