Dielectric measurements of selected ceramics at microwave frequencies

Dielectric measurements of strontium titanate and lead titanate zirconate ceramics are conducted at microwave frequencies using a cylindrical resonant cavity in the TE(sub 011) mode. The perturbations of the electric field are recorded in terms of the frequency shift and Q-changes of the cavity signal. Slater's perturbation equations are used to calculate e' and e" of the dielectric constant as a function of temperature and frequency

Fabrication and Properties of an Anisotropic TiO 2 Dielectric Composite

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65849/1/j.1551-2916.2006.01134.x.pd

Conserve Epitopes of Influenza Virus Induce Innate and Adaptive Immune Responses to Produce Specific Antibody Against M2e Protein

The existing vaccines against influenza are based onthe generation of neutralizing antibody primarilydirected against surface protein, haemagglutinin(HA) and neuraminidase (NA). However, antigenicdrift and occasional shift of these two membraneglycoproteins, HA and NA, make vaccine productioncumbersome and necessitate yearly revision ofthe vaccine seed strains by the World HealthOrganization. For these reasons, many investigatorshave often tried to look at the possibility of generatinga universal vaccine useful against more than oneinfluenza strain. The objective of research was toobtain an alternative antigen as vaccine candidatefor universal flu vaccination, instead of HA and NAcomponents. In this study, we use conserved epitopeM2e which is consist of three major componentsuch as N-terminal M2e2-24 (24 amino acids),transmembrane(59 amino acids) and C-terminal (19amino acids). We design two components of antigen,linier and branched structures. The antigens thenformulated with aluminium hydroxide gel comparedto FCA/IFA adjuvant. These vaccines were testedtheir immunogenicity, and the potency to mature thedendritic cells for stimulating either CD8+ T cell orantibody-mediated immune responses. The antibodytitre and the maturity of dendritic cell indicated bycytokines concentration such as; IFN-ã, IL2 and IL4were measured by ELISA test.The result of researchshowed that the conserved epitope of Me2 2-16 whenincorporated with P25 protein from canine distempervirus (linear structure) in alhydrogel adjuvant hasgreater potential to produce anti-M2e antibodiesthan in Freund adjuvant. Alhydrogel adjuvant hada stronger effect than Freund adjuvant. Alhydrogelalso stimulate the release of IL-2 and IL-4

Genetics, recombination and clinical features of human rhinovirus species C (HRV-C) infections; interactions of HRV-C with other respiratory viruses

To estimate the frequency, molecular epidemiological and clinical associations of infection with the newly described species C variants of human rhinoviruses (HRV), 3243 diagnostic respiratory samples referred for diagnostic testing in Edinburgh were screened using a VP4-encoding region-based selective polymerase chain reaction (PCR) for HRV-C along with parallel PCR testing for 13 other respiratory viruses. HRV-C was the third most frequently detected behind respiratory syncytial virus (RSV) and adenovirus, with 141 infection episodes detected among 1885 subjects over 13 months (7.5%). Infections predominantly targeted the very young (median age 6–12 months; 80% of infections in those <2 years), occurred throughout the year but with peak incidence in early winter months. HRV-C was detected significantly more frequently among subjects with lower (LRT) and upper respiratory tract (URT) disease than controls without respiratory symptoms; HRV-C mono-infections were the second most frequently detected virus (behind RSV) in both disease presentations (6.9% and 7.8% of all cases respectively). HRV variants were classified by VP4/VP2 sequencing into 39 genotypically defined types, increasing the current total worldwide to 60. Through sequence comparisons of the 5′untranslated region (5′UTR), the majority grouped with species A (n = 96; 68%, described as HRV-Ca), the remainder forming a phylogenetically distinct 5′UTR group (HRV-Cc). Multiple and bidirectional recombination events between HRV-Ca and HRV-Cc variants and with HRV species A represents the most parsimonious explanation for their interspersed phylogeny relationships in the VP4/VP2-encoding region. No difference in age distribution, seasonality or disease associations was identified between HRV-Ca and HRV-Cc variants. HRV-C-infected subjects showed markedly reduced detection frequencies of RSV and other respiratory viruses, providing evidence for a major interfering effect of HRV-C on susceptibility to other respiratory virus infections. HRV-C's disease associations, its prevalence and evidence for interfering effects on other respiratory viruses mandates incorporation of rhinoviruses into future diagnostic virology screening

Synthesis of Learning from a Decade of CGIAR Research Programs

The objective of this forward-looking synthesis was to bring together learning from a decade of experience with CGIAR research programs (CRPs), based on existing evaluative evidence. The purpose of this meta-review is to review lessons from the CRP experience to inform the development of future research programs of One CGIAR. The 2021 Synthesis and Lessons Learned from a Decade of CRPs is delivered in response to the request of the CGIAR System Council and aligned with the synthesis terms of reference endorsed by SIMEC in February 2021. The synthesis examined evidence from the two phases of CRP implementation: 2011–2016 and 2017–2019. Four key issues were addressed: (1) patterns and trends between the two phases of CRPs related to the quality of science (QoS) and research for development, achievement of sustainable development outcomes, and management and governance; (2) systemwide issues affecting CRP achievements; (3) recommendations for the future orientation of CGIAR research and innovation; and (4) key evidence gaps and needs for future evaluations. A narrative synthesis approach was used, employing secondary source data from 47 existing evaluations and reviews. External evaluations were systematically coded and analyzed by senior subject matter experts (SMEs) using a standardized analytical framework. A bibliometric trend analysis was carried out, and findings were triangulated against earlier syntheses and validated by members of the Independent Science for Development Council (ISDC), CRP leaders, and expert peer reviewers

Dynamical mass generation of a two-component fermion in Maxwell-Chern-Simons QED_3: The lowest ladder approximation

Dynamical mass generation of a two-component fermion in $QED_3$ with a Chern-Simons term is investigated by solving the Schwinger-Dyson equation formulated in the lowest ladder approximation. Dependence of the dynamical fermion mass on a gauge-fixing parameter, a gauge coupling constant, and a topological mass is examined by approximated analytical and also numerical methods. The inclusion of the Chern-Simons term makes impossible to choose a peculiar gauge in which a wave function renormalization is absent. The numerical evaluation shows that the wave function renormalization is fairly close to 1 in the Landau gauge. It means that this gauge is still a specific gauge where the Ward-Takahashi identity is satisfied approximately. We also find that the dynamical mass is almost constant if the topological mass is larger than the coupling constant, while it decreases when the topological mass is comparable to or smaller than the coupling constant and tends to the value in $QED_3$ without the Chern-Simons term.Comment: 22 pages, 9 figures, Version to appear in Phys. Rev.

Models of Individual Blue Stragglers

This chapter describes the current state of models of individual blue stragglers. Stellar collisions, binary mergers (or coalescence), and partial or ongoing mass transfer have all been studied in some detail. The products of stellar collisions retain memory of their parent stars and are not fully mixed. Very high initial rotation rates must be reduced by an unknown process to allow the stars to collapse to the main sequence. The more massive collision products have shorter lifetimes than normal stars of the same mass, while products between low mass stars are long-lived and look very much like normal stars of their mass. Mass transfer can result in a merger, or can produce another binary system with a blue straggler and the remnant of the original primary. The products of binary mass transfer cover a larger portion of the colour-magnitude diagram than collision products for two reasons: there are more possible configurations which produce blue stragglers, and there are differing contributions to the blended light of the system. The effects of rotation may be substantial in both collision and merger products, and could result in significant mixing unless angular momentum is lost shortly after the formation event. Surface abundances may provide ways to distinguish between the formation mechanisms, but care must be taking to model the various mixing mechanisms properly before drawing strong conclusions. Avenues for future work are outlined.Comment: Chapter 12, in Ecology of Blue Straggler Stars, H.M.J. Boffin, G. Carraro & G. Beccari (Eds), Astrophysics and Space Science Library, Springe

Recombination rate and selection strength in HIV intra-patient evolution

The evolutionary dynamics of HIV during the chronic phase of infection is driven by the host immune response and by selective pressures exerted through drug treatment. To understand and model the evolution of HIV quantitatively, the parameters governing genetic diversification and the strength of selection need to be known. While mutation rates can be measured in single replication cycles, the relevant effective recombination rate depends on the probability of coinfection of a cell with more than one virus and can only be inferred from population data. However, most population genetic estimators for recombination rates assume absence of selection and are hence of limited applicability to HIV, since positive and purifying selection are important in HIV evolution. Here, we estimate the rate of recombination and the distribution of selection coefficients from time-resolved sequence data tracking the evolution of HIV within single patients. By examining temporal changes in the genetic composition of the population, we estimate the effective recombination to be r=1.4e-5 recombinations per site and generation. Furthermore, we provide evidence that selection coefficients of at least 15% of the observed non-synonymous polymorphisms exceed 0.8% per generation. These results provide a basis for a more detailed understanding of the evolution of HIV. A particularly interesting case is evolution in response to drug treatment, where recombination can facilitate the rapid acquisition of multiple resistance mutations. With the methods developed here, more precise and more detailed studies will be possible, as soon as data with higher time resolution and greater sample sizes is available.Comment: to appear in PLoS Computational Biolog

Combining Phylogeography with Distribution Modeling: Multiple Pleistocene Range Expansions in a Parthenogenetic Gecko from the Australian Arid Zone

Phylogenetic and geographic evidence suggest that many parthenogenetic organisms have evolved recently and have spread rapidly. These patterns play a critical role in our understanding of the relative merits of sexual versus asexual reproductive modes, yet their interpretation is often hampered by a lack of detail. Here we present a detailed phylogeographic study of a vertebrate parthenogen, the Australian gecko Heteronotia binoei, in combination with statistical and biophysical modeling of its distribution during the last glacial maximum. Parthenogenetic H. binoei occur in the Australian arid zone and have the widest range of any known vertebrate parthenogen. They are broadly sympatric with their sexual counterparts, from which they arose via hybridization. We have applied nested clade phylogeographic, effective migration, and mismatch distribution analyses to mitochondrial DNA (mtDNA) sequences obtained for 319 individuals sampled throughout the known geographic ranges of two parthenogenetic mitochondrial lineages. These analyses provide strong evidence for past range expansion events from west to east across the arid zone, and for continuing eastward range expansion. Parthenogen formation and range expansion events date to the late Pleistocene, with one lineage expanding from the northwest of its present range around 240,000 years ago and the second lineage expanding from the far west around 70,000 years ago. Statistical and biophysical distribution models support these inferences of recent range expansion, with suitable climatic conditions during the last glacial maximum most likely limited to parts of the arid zone north and west of much of the current ranges of these lineages. Combination of phylogeographic analyses and distribution modeling allowed considerably stronger inferences of the history of this complex than either would in isolation, illustrating the power of combining complementary analytical approaches