719 research outputs found
Properdin and factor H: Opposing players on the alternative complement pathway "see-saw"
This article has been made available through the Brunel Open Access Publishing Fund.Properdin and factor H are two key regulatory proteins having opposite functions in the alternative complement pathway. Properdin up-regulates the alternative pathway by stabilizing the C3bBb complex, whereas factor H downregulates the pathway by promoting proteolytic degradation of C3b. While factor H is mainly produced in the liver, there are several extrahepatic sources. In addition to the liver, factor H is also synthesized in fetal tubuli, keratinocytes, skin fibroblasts, ocular tissue, adipose tissue, brain, lungs, heart, spleen, pancreas, kidney, muscle, and placenta. Neutrophils are the major source of properdin, and it is also produced by monocytes, T cells and bone marrow progenitor cell line. Properdin is released by neutrophils from intracellular stores following stimulation by N-formyl-methionine-leucine-phenylalanine (fMLP) and tumor necrosis factor alpha (TNF-α). The HEP G2 cells derived from human liver has been found to produce functional properdin. Endothelial cells also produce properdin when induced by shear stress, thus is a physiological source for plasma properdin. The diverse range of extrahepatic sites for synthesis of these two complement regulators suggests the importance and need for local availability of the proteins. Here, we discuss the significance of the local synthesis of properdin and factor H. This assumes greater importance in view of recently identified unexpected and novel roles of properdin and factor H that are potentially independent of their involvement in complement regulation
Interventions to support contraceptive choice and use: a global systematic map of systematic reviews
BACKGROUND: To review the highest level of available evidence, a systematic map identified systematic reviews that evaluated the effectiveness of interventions to improve contraception choice and increase contraception use. METHODS: Systematic reviews published since 2000 were identified from searches of nine databases. Data were extracted using a coding tool developed for this systematic map. Methodological quality of included reviews was assessed using AMSTAR 2 criteria. FINDINGS AND CONCLUSION: Fifty systematic reviews reported evaluations of interventions for contraception choice and use addressing three domains (individual, couples, community); Meta-analyses in 11 of the reviews mostly addressed interventions for individuals. We identified 26 reviews covering High Income Countries, 12 reviews covering Low Middle-Income Countries and the rest a mix of both. Most reviews (15) focussed on psychosocial interventions, followed by incentives (6) and m-health interventions (6). The strongest evidence from meta-analyses is for the effectiveness of motivational interviewing, contraceptive counselling, psychosocial interventions, school-based education, and interventions promoting contraceptive access, demand-generation interventions (community and facility based, financial mechanisms and mass media), and mobile phone message interventions. Even in resource constrained settings, community-based interventions can increase contraceptive use. There are gaps in the evidence on interventions for contraception choice and use, and limitations in study designs and lack of representativeness. Most approaches focus on individual women rather than couples or wider socio-cultural influences on contraception and fertility. This review identifies interventions which work to increase contraception choice and use, and these could be implemented in school, healthcare or community settings
Fractional quantum Hall effect in the absence of Landau levels
It has been well-known that topological phenomena with fractional
excitations, i.e., the fractional quantum Hall effect (FQHE) \cite{Tsui1982}
will emerge when electrons move in Landau levels. In this letter, we report the
discovery of the FQHE in the absence of Landau levels in an interacting fermion
model. The non-interacting part of our Hamiltonian is the recently proposed
topologically nontrivial flat band model on the checkerboard lattice
\cite{sun}. In the presence of nearest-neighboring repulsion (), we find
that at 1/3 filling, the Fermi-liquid state is unstable towards FQHE. At 1/5
filling, however, a next-nearest-neighboring repulsion is needed for the
occurrence of the 1/5 FQHE when is not too strong. We demonstrate the
characteristic features of these novel states and determine the phase diagram
correspondingly.Comment: 6 pages and 4 figure
The utilisation of systematic review evidence in formulating India's National Health Programme guidelines between 2007 to 2021
Evidence informed policymaking integrates the best available evidence on programme outcomes to guide decisions at all stages of the policy process and its importance becomes more pronounced in resource constrained settings. In this paper, we have reviewed the use of systematic review evidence in framing National Health Programme (NHP) guidelines in India. We searched official websites of the different NHPs, linked to the main website of the Ministry of Health and Family Welfare (MoHFW), in December 2020 and January 2021. NHP guideline documents with systematic review evidence were identified and information on the use of this evidence was extracted. We classified the identified systematic review evidence according to its use in the guideline documents and analysed the data to provide information on the different factors and patterns linked to the use of systematic review evidence in these documents. Systematic reviews were mostly visible in guideline documents addressing maternal and newborn health, communicable diseases and immunization. These systematic reviews were cited in the guidelines to justify the need for action, to justify recommendations for action and opportunities for local adaptation; and to highlight implementation challenges and justify implementation strategies. Guideline documents addressing implementation cited systematic reviews about the problems and policy options more often than citing systematic reviews about implementation. Systematic reviews were linked directly to support statements in few guideline documents, and sometimes the reviews were not appropriately cited. Most of the systematic reviews providing information on the nature and scale of the policy problem included Indian data. It was seen that since 2014, India has been increasingly using systematic review evidence for public health policymaking particularly for some of its high priority NHPs. This complements the increasing investment in research synthesis centres and procedures to support evidence informed decision making, demonstrating the continued evolution of India's evidence policy system
Anyons in a weakly interacting system
We describe a theoretical proposal for a system whose excitations are anyons
with the exchange phase pi/4 and charge -e/2, but, remarkably, can be built by
filling a set of single-particle states of essentially noninteracting
electrons. The system consists of an artificially structured type-II
superconducting film adjacent to a 2D electron gas in the integer quantum Hall
regime with unit filling fraction. The proposal rests on the observation that a
vacancy in an otherwise periodic vortex lattice in the superconductor creates a
bound state in the 2DEG with total charge -e/2. A composite of this
fractionally charged hole and the missing flux due to the vacancy behaves as an
anyon. The proposed setup allows for manipulation of these anyons and could
prove useful in various schemes for fault-tolerant topological quantum
computation.Comment: 7 pages with 3 figures. For related work and info visit
http://www.physics.ubc.ca/~fran
Complete larval development of the hermit crabs Clibanarius aequabilis and Clibanarius erythropus (Decapoda : Anomura : Diogenidae), under laboratory conditions, with a revision of the larval features of genus Clibanarius
The complete larval development (four zoeae and one megalopa) of Clibanarius aequabilis and C. erythropus, reared under laboratory conditions, is described and illustrated. The larval stages of the two northeastern Atlantic Clibanarius species cannot be easily differentiated. Their morphological characters are compared with those of other known Clibanarius larvae. The genus Clibanarius is very homogeneous with respect to larval characters. All Clibanarius zoeae display a broad and blunt rostrum, smooth abdominal segments and an antennal scale without a terminal spine. Beyond the second zoeal stage, the fourth telson process is present as a fused spine, and the uropods are biramous. In the fourth larval stage all species display a mandibular palp. The Clibanarius megalopa presents weakly developed or no ocular scales, symmetrical chelipeds, apically curved corneous dactylus in the second and third pereiopods, and 5-11 setae on the posterior margin of the telson. Apart from the number of zoeal stages, Clibanarius species may be separated, beyond the second zoeal stage, by the telson formula and the morphology of the fourth telson process.info:eu-repo/semantics/publishedVersio
Paired and clustered quantum Hall states
We briefly summarize properties of quantum Hall states with a pairing or
clustering property. Their study employs a fundamental connection with
parafermionic Conformal Field Theories. We report on closed form expressions
for the many-body wave functions and on multiplicities of the fundamental
quasi-hole excitations.Comment: 13 pages, Contribution to the proceedings of the NATO Advanced
Research Workshop "Statistical Field Theories" Como (Italy), June 18-23 200
On the Relationship Between Ultrasonic and Micro-Structural Properties of Imperfect Interfaces in Layered Solids
The interaction of ultrasonic waves with interfaces formed by two non-conforming, rough surfaces in contact has been the subject of numerous investigations [1–10]. The motivations behind these studies have been various: from the assessment of the real area of contact between two rough surfaces [1], to the modeling of crack closure near the tip of a fatigue crack [4]; from the identification of the nature of interfacial imperfections in kissing and partial bonds [6], to the generation of ultrasonic waves [8]. In most of these studies, the characterization of the interfacial properties has been attempted by studying the reflection of longitudinal and shears waves at normal incidence. Only recently, the problem concerning the interaction of ultrasonic waves with realistic complex systems such as that formed by two neighboring imperfect interfaces has been addressed. Lavrentyev and Rokhlin [9, 10] used ultrasonic spectroscopy to evaluate the interfacial conditions from the spectra of longitudinal and shear waves reflected normally from the interfaces
Exploring 4D Quantum Hall Physics with a 2D Topological Charge Pump
The discovery of topological states of matter has profoundly augmented our
understanding of phase transitions in physical systems. Instead of local order
parameters, topological phases are described by global topological invariants
and are therefore robust against perturbations. A prominent example thereof is
the two-dimensional integer quantum Hall effect. It is characterized by the
first Chern number which manifests in the quantized Hall response induced by an
external electric field. Generalizing the quantum Hall effect to
four-dimensional systems leads to the appearance of a novel non-linear Hall
response that is quantized as well, but described by a 4D topological invariant
- the second Chern number. Here, we report on the first observation of a bulk
response with intrinsic 4D topology and the measurement of the associated
second Chern number. By implementing a 2D topological charge pump with
ultracold bosonic atoms in an angled optical superlattice, we realize a
dynamical version of the 4D integer quantum Hall effect. Using a small atom
cloud as a local probe, we fully characterize the non-linear response of the
system by in-situ imaging and site-resolved band mapping. Our findings pave the
way to experimentally probe higher-dimensional quantum Hall systems, where new
topological phases with exotic excitations are predicted
Evaluating the use of the Child and Adolescent Intellectual Disability Screening Questionnaire (CAIDS-Q) to estimate IQ in children with low intellectual ability
In situations where completing a full intellectual assessment is not possible or desirable the clinician or researcher may require an alternative means of accurately estimating intellectual functioning. There has been limited research in the use of proxy IQ measures in children with an intellectual disability or low IQ. The present study aimed to provide a means of converting total scores from a screening tool (the Child and Adolescent Intellectual Disability Screening Questionnaire: CAIDS-Q) to an estimated IQ. A series of linear regression analyses were conducted on data from 428 children and young people referred to clinical services, where FSIQ was predicted from CAIDS-Q total scores. Analyses were conducted for three age groups between ages 6 and 18 years. The study presents a conversion table for converting CAIDS-Q total scores to estimates of FSIQ, with corresponding 95% prediction intervals to allow the clinician or researcher to estimate FSIQ scores from CAIDS-Q total scores. It is emphasised that, while this conversion may offer a quick means of estimating intellectual functioning in children with a below average IQ, it should be used with caution, especially in children aged between 6 and 8 years old
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