26 research outputs found
Dengue viruses and promising envelope protein domain III-based vaccines
Get PDFAbstract
Dengue viruses are emerging mosquito-borne pathogens belonging to Flaviviridae family which are transmitted to humans via the bites of infected mosquitoes Aedes aegypti and Aedes albopictus. Because of the wide distribution of these mosquito vectors, more than 2.5 billion people are approximately at risk of dengue infection. Dengue viruses cause dengue fever and severe life-threatening illnesses as well as dengue hemorrhagic fever and dengue shock syndrome. All four serotypes of dengue virus can cause dengue diseases, but the manifestations are nearly different depending on type of the virus in consequent infections. Infection by any serotype creates life-long immunity against the corresponding serotype and temporary immunity to the others. This transient immunity declines after a while (6 months to 2 years) and is not protective against other serotypes, even may enhance the severity of a secondary heterotypic infection with a different serotype through a phenomenon known as antibody-depended enhancement (ADE). Although, it can be one of the possible explanations for more severe dengue diseases in individuals infected with a different serotype after primary infection. The envelope protein (E protein) of dengue virus is responsible for a wide range of biological activities, including binding to host cell receptors and fusion to and entry into host cells. The E protein, and especially its domain III (EDIII), stimulates host immunity responses by inducing protective and neutralizing antibodies. Therefore, the dengue E protein is an important antigen for vaccine development and diagnostic purposes. Here, we have provided a comprehensive review of dengue disease, vaccine design challenges, and various approaches in dengue vaccine development with emphasizing on newly developed envelope domain III-based dengue vaccine candidates.
Keywords:
Dengue virus Envelope protein Chimeric vaccine Disease Immunogenicit
Direct optical probe of magnon topology in two-dimensional quantum magnets
Get PDFControlling edge states of topological magnon insulators is a promising route to stable spintronics devices. However, to experimentally ascertain the topology of magnon bands is a challenging task. Here we derive a fundamental relation between the light-matter coupling and the quantum geometry of magnon states. This allows to establish the two-magnon Raman circular dichroism as an optical probe of magnon topology in honeycomb magnets, in particular of the Chern number and the topological gap. Our results pave the way for interfacing light and topological magnons in functional quantum devices
All-optical generation of antiferromagnetic magnon currents via the magnon circular photogalvanic effect
Get PDFWe introduce the magnon circular photogalvanic effect enabled by two-magnon Raman scattering. This provides an all-optical pathway to the generation of directed magnon currents with circularly polarized light in honeycomb antiferromagnetic insulators. The effect is the leading order contribution to magnon photocurrent generation via optical fields. Control of the magnon current by the polarization and angle of incidence of the laser is demonstrated. Experimental detection by sizable inverse spin Hall voltages in platinum contacts is proposed
SEISMIC PERFORMANCE ASSESSMENT OF ISOLATED STEEL MOMENT FRAMES WITH LOSS APPROACH
No full textEarthquakes pose inevitable damage and loss of life in structures. Seismic isolation has proven to be an effective method to reduce the seismic vibration and mitigate seismic losses and damage costs. The isolator drastically reduces the main frequency of the structure and subsequently lowers the acceleration of the floors. While this flexible layer protects the building from destruction,
it undergoes a relatively large displacement demand. Isolated structures as well as fixed structures could suffer from inelastic deformation and serious damage under intense seismic ground motions. Performance-based seismic design (PBSD) is a concept that permits the design of buildings with reliable understanding of the risk of life, occupancy, and economic loss that may occur as a result of future earthquakes. Also, Seismic loss estimation method combines seismic hazard, structural response, damage fragility, and damage consequences of allowing quantification of seismic risk based on seismic performance of a building is expressed as the probable damage and resulting consequences of a building's response to earthquake shaking. Nonlinear 4-story archetypes of conventional special moment resisting frame and isolated intermediate moment resisting frame were compared with each other under Far-Field and Near-Field ground motions. Detailed three-dimensional (3D) numerical models of the structures were developed in OpenSees software and Performance Assessment Calculation Tool (PACT) was used for the loss estimation of archetypes. The decision variables in this study were defined as expected annualized repair cost or financial losses (EAL) and expected annualized fatalities (EAF). The analysis results showed that seismic isolation reduces collapse probability, EAL and EAF in superstructures significantly and can be cost effective in mitigating seismic risk. Seismic isolation reduces EAL by 72\% and 67\% under Far-Field and Near-Field ground motions, respectively. Furthermore the result of this study showing that the effectivity of isolation system decreases in Near-Field compared with Far-Field ground motions. The economic feasibility studies showed that if isolation system is used, pay-back period times are around 14 and 18 years under Far-Field and Near-Field ground motions, respectively. The benefit of loss estimation approach is an improved method to assess the effectiveness of isolation system in terms of loss estimation
Prediction of deterioration components in reinforcement concrete columns using machine learning techniques
No full textNew performance-based design approaches in earthquake engineering aim to accurately and transparently assess the risk of loss of life and structural damage. Advanced analytical models are used to determine the performance of structures, with one of the key components being the deterioration of structural members under seismic loads.
Multilinear backbone curves are commonly used in regulations and software to simplify the behavior of members subjected to seismic loads, including the deterioration components. This paper proposes using machine learning models to predict the deterioration components of reinforced concrete (RC) columns. A dataset of 255 experimental data from 1973 to 2002 is used to predict the deterioration components using different machine learning methods. The RC columns have three failure modes: bending, shearing, and bending-shearing. The deterioration components predicted by the analytical relationships are compared with the results obtained from machine learning methods. The dataset includes 14 features as model inputs and 3 features as outputs. The paper examines three algorithms for predictions: AdaBoost, artificial neural network (ANN), and random forest (RF). The analysis is conducted using Python software. The results show that the random forest model has an accuracy rate of 91% for the Plastic chord rotations from yield to cap , 81% for Post-capping plastic-rotation capacity from the cap to point of zero strength , and 88% for normalized energy dissipation capacity compared to other algorithms.
Also, the results obtained from the predicting models have considerable accuracy compared to analytical relationships. Compared to analytical models, the random forest model has significantly been improved in terms of root mean square error (RMSE), mean absolute error (MAE) and coefficient determination (R2). These improvement are 79% , 75.3% and 46.5% in (R2), 63.7% , 48.5% and 86.7 in (RMSE), 64% , 92% and 89.4% in (MAE).The results showed that the random forest model has been significantly improved the accuracy of determination of deterioration components compared with analytical models
The Effects of LeukemiaInhibitory Factor onDevelopment of MousePreimplantation Embryo
No full textIntroduction and Objective: Recent studies have demonstrated
that mammalian preimplantation embryos are exposed to a mixture
of many different growth factors and cytokines, expressed by the
follicles, oviducts and endometrium. Receptors for many of these
growth factors have also been shown to be expressed by
preimplantation embryos. In vitro culture of human and animal's
embryos in conventional media lacking growth factors can result in
suboptimal growth and a variety of short-term and long-term
developmental abnormalities. One of these factors is Leukemia
Inhibitory Factor (LIF). The aim of this study was to evaluate the
effects of LIF on the mouse preimplantation embryo development.
Materials & Methods: Six to eight weeks old NMRI mice were
superovulated by injection of 10IU PMSG and 10IU HCG 48h later.
The mated mice were killed 48 hours after HCG injection, oviducts
were flushed and two-cell embryos were collected and divided
randomly to two groups (control and treatment). Control medium
was HTF and treatment medium was HTF+1000u/ml LIF. In each
group the embryos were cultured in an incubator at 37°C with 5%
CO2 for 72h.The state of embryo development was evaluated in 12
hours interval using inverted microscope.
Results: There was not any significant difference in the rate of
morolla and blastocyst formation after 36 hours. In comparing
hatching rates, 60 and 72 hours after culture, there were significant
difference between control and treatment groups (p< 0.008).
Conclusion: LIF doesn’t provide obvious stimulation in the early
mouse embryo development until morolla stage. However, it has
positive effects on preimplantation blastocyst growth, differentiation
and hatching
Detection and measurement of micrometeoroids with LISA Pathfinder
No full textThe Solar System contains a population of dust and small particles originating from asteroids, comets, and other bodies. These particles have been studied using a number of techniques ranging from in-situ satellite detectors to analysis of lunar microcraters to ground-based observations of zodiacal light. In this paper, we describe an approach for using the LISA Pathfinder (LPF) mission as an instrument to detect and characterize the dynamics of dust particles in the vicinity of Earth-Sun L1. Launched on Dec. 3rd, 2015, LPF is a dedicated technology demonstrator mission that will validate several key technologies for a future space-based gravitational-wave observatory. The primary science instrument aboard LPF is a precision accelerometer which we show will be capable of sensing discrete momentum impulses as small as 4 × 10-8 N s. We then estimate the rate of such impulses resulting from impacts of micrometeoroids based on standard models of the micrometeoroid environment in the inner solar system. We find that LPF may detect dozens to hundreds of individual events corresponding to impacts of particles with masses >10-9g during LPF’s roughly six-month science operations phase in a 5 × 105 km by 8 × 105 km Lissajous orbit around L1. In addition, we estimate the ability of LPF to characterize individual impacts by measuring quantities such as total momentum transferred, direction of impact, and location of impact on the spacecraft. Information on flux and direction provided by LPF may provide insight as to the nature and origin of the individual impact and help constrain models of the interplanetary dust complex in general. Additionally, this direct in situ measurement of micrometeoroid impacts will be valuable to designers of future spacecraft targeting the environment around L1
Transcriptional Analysis of Stearoyl-Acyl Carrier Protein Desaturase Genes from Olive (Olea europaea) in Relation to the Oleic Acid Content of the Virgin Olive Oil
No full text7 Figuras.-- 1 TablaThe specific contribution of different stearoyl-ACP desaturase (SAD) genes to the oleic acid content in olive (Olea europaea) fruit has been studied. Toward that end, we isolated three distinct cDNA clones encoding three SAD isoforms from olive (cv. Picual), as revealed by sequence analysis. The expression levels of olive SAD genes were determined in different tissues from Picual and Arbequina cultivars, including developing mesocarp and seed, together with the unsaturated fatty acid content. Lipid and gene expression analyses indicate that OeSAD2 seems to be the main gene contributing to the oleic acid content of the olive fruit and, therefore, of the virgin olive oil. This conclusion was confirmed when the study was extended to Hojiblanca, Picudo, and Manzanilla cultivars. Furthermore, our data indicate that the olive microsomal oleate desaturase gene OeFAD2-2, but not OeSAD2, is responsible for the linoleic acid content in the virgin olive oil.Research was supported by the Spanish Ministry of Economy and Competitiveness (Grant AGL2014-55300-R). F.P. was the recipient of a Ph.D. fellowship from the National Institute of Genetic Engineering and Biotechnology (Iran), and M.L.H. was the recipient of a contract from the JAE-Postdoctoral CSIC program (Spain)
Direct optical probe of magnon topology in two-dimensional quantum magnets
No full textControlling edge states of topological magnon insulators is a promising route to stable spintronics devices. However, to experimentally ascertain the topology of magnon bands is a challenging task. Here we derive a fundamental relation between the light-matter coupling and the quantum geometry of magnon states. This allows to establish the two-magnon Raman circular dichroism as an optical probe of magnon topology in honeycomb magnets, in particular of the Chern number and the topological gap. Our results pave the way for interfacing light and topological magnons in functional quantum devices
Transcriptional Analysis of Stearoyl-Acyl Carrier Protein Desaturase Genes from Olive (Olea europaea) in Relation to the Oleic Acid Content of the Virgin Olive Oil
No full textThe specific contribution
of different stearoyl-ACP desaturase
(<i>SAD</i>) genes to the oleic acid content in olive (Olea europaea) fruit has been studied. Toward that
end, we isolated three distinct cDNA clones encoding three SAD isoforms
from olive (cv. Picual), as revealed by sequence analysis. The expression
levels of olive <i>SAD</i> genes were determined in different
tissues from Picual and Arbequina cultivars, including developing
mesocarp and seed, together with the unsaturated fatty acid content.
Lipid and gene expression analyses indicate that <i>OeSAD2</i> seems to be the main gene contributing to the oleic acid content
of the olive fruit and, therefore, of the virgin olive oil. This conclusion
was confirmed when the study was extended to Hojiblanca, Picudo, and
Manzanilla cultivars. Furthermore, our data indicate that the olive
microsomal oleate desaturase gene <i>OeFAD2-2</i>, but not <i>OeSAD2</i>, is responsible for the linoleic acid content in
the virgin olive oil
