2,173 research outputs found
A FAMILY OF CATION ATPASE-LIKE MOLECULES FROM PLASMODIUM-FALCIPARUM
Abstract. We report the nucleotide and derived amino acid sequence of the ATPase 1 gene from Plasmodium falciparum. The amino acid sequence shares homology with the family of "P-type cation transloeating ATPases in conserved regions important for nucleotide binding, conformational change, or phosphorylation. The gene, which is present on chromosome 5, has a product longer than any other reported for a P-type ATPase. Interstrain analysis from 12 parasite isolates by the polymerase chain reaction reveals that a 330-bp nucleotide sequence encoding three cytoplasmic regions conserved in cation ATPases (regions a-c) is of constant length. By contrast, another 360-bp sequence which is one of four regions we refer to as
Product Service System Innovation in the Smart City
Product service systems (PSS) may usefully form part of the mix of innovations necessary to move society toward more sustainable futures. However, despite such potential, PSS implementation is highly uneven and limited. Drawing on an alternate socio-technical perspective of innovation, this paper provides fresh insights, on among other things the role of context in PSS innovation, to address this issue. Case study research is presented focusing on a use orientated PSS in an urban environment: the Copenhagen city bike scheme. The paper shows that PSS innovation is a situated complex process, shaped by actors and knowledge from other locales. It argues that further research is needed to investigate how actors interests shape PSS innovation. It recommends that institutional spaces should be provided in governance landscapes associated with urban environments to enable legitimate PSS concepts to co-evolve in light of locally articulated sustainability principles and priorities
Noncommutative generalizations of theorems of Cohen and Kaplansky
This paper investigates situations where a property of a ring can be tested
on a set of "prime right ideals." Generalizing theorems of Cohen and Kaplansky,
we show that every right ideal of a ring is finitely generated (resp.
principal) iff every "prime right ideal" is finitely generated (resp.
principal), where the phrase "prime right ideal" can be interpreted in one of
many different ways. We also use our methods to show that other properties can
be tested on special sets of right ideals, such as the right artinian property
and various homological properties. Applying these methods, we prove the
following noncommutative generalization of a result of Kaplansky: a (left and
right) noetherian ring is a principal right ideal ring iff all of its maximal
right ideals are principal. A counterexample shows that the left noetherian
hypothesis cannot be dropped. Finally, we compare our results to earlier
generalizations of Cohen's and Kaplansky's theorems in the literature.Comment: 41 pages. To appear in Algebras and Representation Theory. Minor
changes were made to the numbering system, in order to remain consistent with
the published versio
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Auditory, phonological and semantic factors in the recovery from Wernicke’s aphasia post stroke: predictive value and implications for rehabilitation
Background: Understanding the factors that influence language recovery in aphasia is important for improving prognosis and treatment. Chronic comprehension impairments Wernicke’s-type aphasia (WA) are associated with impairments in auditory and phonological processing, compounded by semantic and executive difficulties. This study investigated whether the recovery of auditory, phonological, semantic or executive factors underpins the recovery from WA comprehension impairments by charting changes in the neuropsychological profiles from the sub-acute to the chronic phase.
Method: This study used a prospective, longitudinal, observational design. Twelve WA participants with superior temporal lobe lesions were recruited before 2 months post stroke onset (MPO). Language comprehension was measured alongside a neuropsychological profile of auditory, phonological and semantic processing alongside phonological short-term memory and nonverbal reasoning at three post stroke time points: 2.5, 5 and 9MPO.
Results: Language comprehension displayed a strong and consistent recovery between 2.5 and 9MPO. Improvements were also seen for slow auditory temporal processing, phonological short-term memory, and semantic processing, but not for rapid auditory temporal, spectrotemporal and phonological processing. Despite their lack of improvement, rapid auditory temporal processing at 2.5MPO and phonological processing at 5MPO predicated comprehension outcomes at 9MPO.
Conclusions: These results indicate that recovery of language comprehension in WA can be predicted from fixed auditory processing in the subacute stage. This suggests that speech comprehension recovery in WA results from reorganisation of the remaining language comprehension network to enable the residual speech signal to be processed more efficiently, rather than partial recovery of underlying auditory, phonological or semantic processing abilities
Effects of steady state free precession parameters on cardiac mass, function, and volumes
G0400444/Medical Research Council/United Kingdom
Wellcome Trust/United Kingdo
Allele frequencies of hemojuvelin gene (HJV) I222N and G320V missense mutations in white and African American subjects from the general Alabama population
BACKGROUND: Homozygosity or compound heterozygosity for coding region mutations of the hemojuvelin gene (HJV) in whites is a cause of early age-of-onset iron overload (juvenile hemochromatosis), and of hemochromatosis phenotypes in some young or middle-aged adults. HJV coding region mutations have also been identified recently in African American primary iron overload and control subjects. Primary iron overload unexplained by typical hemochromatosis-associated HFE genotypes is common in white and black adults in Alabama, and HJV I222N and G320V were detected in a white Alabama juvenile hemochromatosis index patient. Thus, we estimated the frequency of the HJV missense mutations I222N and G320V in adult whites and African Americans from Alabama general population convenience samples. METHODS: We evaluated the genomic DNA of 241 Alabama white and 124 African American adults who reported no history of hemochromatosis or iron overload to detect HJV missense mutations I222N and G320V using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Analysis for HJV I222N was performed in 240 whites and 124 African Americans. Analysis for HJV G320V was performed in 241 whites and 118 African Americans. RESULTS: One of 240 white control subjects was heterozygous for HJV I222N; she was also heterozygous for HFE C282Y, but had normal serum iron measures and bone marrow iron stores. HJV I222N was not detected in 124 African American subjects. HJV G320V was not detected in 241 white or 118 African American subjects. CONCLUSIONS: HJV I222N and G320V are probably uncommon causes or modifiers of primary iron overload in adult whites and African Americans in Alabama. Double heterozygosity for HJV I222N and HFE C282Y may not promote increased iron absorption
How Do Bone Marrow Lesions Cause Osteoarthritis Pain? a Structural and Functional Tissue-Based Study
Background/Purpose: Susceptibility to ankylosing spondylitis (AS) is primarily genetic; thus far 113 susceptibility variants for AS have been identified. However, most of the AS associated SNPs do not directly affect protein-coding genes. Studies of disease- and trait-associated SNPs suggest they may act by affecting gene regulatory regions in specific cell types or tissues. Therefore, identifying the AS relevant cell types is crucial for further mechanistic studies. Methods: We applied several bioinformatics methods to utilize epigenetic, gene and protein expression information to identify the primary relevant cell types through which genetic variants associated with AS operate. In total, there are 113 AS associated loci; 39 of them show genome-wide significance in AS-only analyses, whereas the remainder are genome-wide significant in analyses leveraging pleiotrophy with other related diseases (Crohn’s disease (CD), psoriasis, primary sclerosing cholangitis (PSC) and ulcerative colitis (UC))1. Results: AS-associated SNPs are disproportionately found in regions bearing epigenetic marks indicating transcriptional activity found in immune cell types including monocytes, CD4+ and CD8+ T cells, NK cells, regulatory T cells, and B cells. Gene expression studies showed enrichment of AS associated loci in genes specifically expressed in monocytes and NK cells while protein expression study shows protein products of AS associated loci were significantly enriched in CD8+ T cells. Epigenetic analyses also showed evidence that AS-associated signals operate in gut cell types including in mucosa from the small intestine, sigmoid colon and rectum. These findings particularly relate to pleiotropic loci also associated with IBD, psoriasis, and PSC. Conclusion: These findings highlight the role of key immune cell types in the mechanism by which genetic associations with AS drive the disease, as well as providing further evidence for the involvement of the gut in the pathogenesis of AS. 1Ellinghaus D. at al, Nature Genetics 201
Spatial contrast sensitivity in adolescents with autism spectrum disorders
Adolescents with autism spectrum disorders (ASD) and typically developing (TD) controls underwent a rigorous psychophysical assessment that measured contrast sensitivity to seven spatial frequencies (0.5-20 cycles/degree). A contrast sensitivity function (CSF) was then fitted for each participant, from which four measures were obtained: visual acuity, peak spatial frequency, peak contrast sensitivity, and contrast sensitivity at a low spatial frequency. There were no group differences on any of the four CSF measures, indicating no differential spatial frequency processing in ASD. Although it has been suggested that detail-oriented visual perception in individuals with ASD may be a result of differential sensitivities to low versus high spatial frequencies, the current study finds no evidence to support this hypothesis
Selection at a single locus leads to widespread expansion of toxoplasma gondii lineages that are virulent in mice
The determinants of virulence are rarely defined for eukaryotic parasites such as T. gondii, a widespread parasite of mammals that also infects humans, sometimes with serious consequences. Recent laboratory studies have established that variation in a single secreted protein, a serine/threonine kinase known as ROPO18, controls whether or not mice survive infection. Here, we establish the extent and nature of variation in ROP18among a collection of parasite strains from geographically diverse regions. Compared to other genes, ROP18 showed extremely high levels of diversification and changes in expression level, which correlated with severity of infection in mice. Comparison with an out-group demonstrated that changes in the upstream region that regulates expression of ROP18 led to an historical increase in the expression and exposed the protein to diversifying selective pressure. Surprisingly, only three atypically distinct protein variants exist despite marked genetic divergence elsewhere in the genome. These three forms of ROP18 are likely adaptations for different niches in nature, and they confer markedly different virulence to mice. The widespread distribution of a single mouse-virulent allele among geographically and genetically disparate parasites may have consequences for transmission and disease in other hosts, including humans
Rituximab for maintenance of remission in ANCA-associated vasculitis: expert consensus guidelines
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