218 research outputs found
Ncs2* mediates in vivo virulence of pathogenic yeast through sulphur modification of cytoplasmic transfer RNA.
Fungal pathogens threaten ecosystems and human health. Understanding the molecular basis of their virulence is key to develop new treatment strategies. Here, we characterize NCS2*, a point mutation identified in a clinical baker's yeast isolate. Ncs2 is essential for 2-thiolation of tRNA and the NCS2* mutation leads to increased thiolation at body temperature. NCS2* yeast exhibits enhanced fitness when grown at elevated temperatures or when exposed to oxidative stress, inhibition of nutrient signalling, and cell-wall stress. Importantly, Ncs2* alters the interaction and stability of the thiolase complex likely mediated by nucleotide binding. The absence of 2-thiolation abrogates the in vivo virulence of pathogenic baker's yeast in infected mice. Finally, hypomodification triggers changes in colony morphology and hyphae formation in the common commensal pathogen Candida albicans resulting in decreased virulence in a human cell culture model. These findings demonstrate that 2-thiolation of tRNA acts as a key mediator of fungal virulence and reveal new mechanistic insights into the function of the highly conserved tRNA-thiolase complex
A comprehensive study of GRB 070125, a most energetic gamma ray burst
We present a comprehensive multiwavelength analysis of the bright, long
duration gamma-ray burst GRB 070125, comprised of observations in -ray,
X-ray, optical, millimeter and centimeter wavebands. Simultaneous fits to the
optical and X-ray light curves favor a break on day 3.78, which we interpret as
the jet break from a collimated outflow. Independent fits to optical and X-ray
bands give similar results in the optical bands but shift the jet break to
around day 10 in the X-ray light curve. We show that for the physical
parameters derived for GRB 070125, inverse Compton scattering effects are
important throughout the afterglow evolution. While inverse Compton scattering
does not affect radio and optical bands, it may be a promising candidate to
delay the jet break in the X-ray band. Radio light curves show rapid flux
variations, which are interpreted as due to interstellar scintillation, and are
used to derive an upper limit of cm on the radius of the
fireball in the lateral expansion phase of the jet. Radio light curves and
spectra suggest a high synchrotron self absorption frequency indicative of the
afterglow shock wave moving in a dense medium. Our broadband modeling favors a
constant density profile for the circumburst medium over a wind-like profile
(). However, keeping in mind the uncertainty of the parameters, it is
difficult to unambiguously distinguish between the two density profiles. Our
broadband fits suggest that \event is a burst with high radiative efficiency
().Comment: 50 pages, 33 figures, sty file included, Appeared in 20 Aug 2008
edition of Astrophysical Journa
Operationalisation of Mild Cognitive Impairment: A Graphical Approach
A new online tool allows mapping of the different classifications of mild cognitive impairment
Brief cognitive assessment in a UK population sample â distributional properties and the relationship between the MMSE and an extended mental state examination
BACKGROUND: Despite the MMSE's known flaws, it is still used extensively as both a screening instrument for dementia and a population measure of cognitive ability. The aim of this paper is to provide data on the distribution of MMSE scores in a representative sample from the UK population and to compare it with an extended cognitive assessment (EMSE) which covers a wider range of cognitive domains and provides a wider range of difficulty levels. METHODS: The MMSE and the EMSE were administered to over 12,000 participants at the screening stage of the MRC Cognitive Function and Ageing Study (MRC CFAS). MRC CFAS is a multi-centre population-based study in England and Wales with respondents aged 65 years and older. RESULTS: Normative values on the MMSE and EMSE are presented by age group, sex and level of education. There are very large differences between age groups, with smaller differences seen between the sexes and by level of education. The EMSE extends the scores at the high end of the ability range, but is no better than the MMSE at differentiating between dementia and non-dementia. CONCLUSION: Population-derived norms are valuable for comparing an individual's score to the score that would be expected among the general population, given the individual's specific demographic characteristics
Hsp72 is targeted to the mitotic spindle by Nek6 to promote K-fiber assembly and mitotic progression
Hsp70 proteins represent a family of chaperones that regulate cellular homeostasis and are required for cancer cell survival. However, their function and regulation in mitosis remain unknown. In this paper, we show that the major inducible cytoplasmic Hsp70 isoform, Hsp72, is required for assembly of a robust bipolar spindle capable of efficient chromosome congression. Mechanistically, Hsp72 associates with the K-fiber-stabilizing proteins, ch-TOG and TACC3, and promotes their interaction with each other and recruitment to spindle microtubules (MTs). Targeting of Hsp72 to the mitotic spindle is dependent on phosphorylation at Thr-66 within its nucleotide-binding domain by the Nek6 kinase. Phosphorylated Hsp72 concentrates on spindle poles and sites of MT-kinetochore attachment. A phosphomimetic Hsp72 mutant rescued defects in K-fiber assembly, ch-TOG/TACC3 recruitment and mitotic progression that also resulted from Nek6 depletion. We therefore propose that Nek6 facilitates association of Hsp72 with the mitotic spindle, where it promotes stable K-fiber assembly through recruitment of the ch-TOG-TACC3 complex
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The relative contributions of speechreading and vocabulary to deaf and hearing children's reading ability
Background
Vocabulary knowledge and speechreading are important for deaf children's reading development but it is unknown whether they are independent predictors of reading ability.
Aims
This study investigated the relationships between reading, speechreading and vocabulary in a large cohort of deaf and hearing children aged 5 to 14 years.
Methods and procedures
86 severely and profoundly deaf children and 91 hearing children participated in this study. All children completed assessments of reading comprehension, word reading accuracy, speechreading and vocabulary.
Outcomes and results
Regression analyses showed that vocabulary and speechreading accounted for unique variance in both reading accuracy and comprehension for deaf children. For hearing children, vocabulary was an independent predictor of both reading accuracy and comprehension skills but speechreading only accounted for unique variance in reading accuracy.
Conclusions and implications
Speechreading and vocabulary are important for reading development in deaf children. The results are interpreted within the Simple View of Reading framework and the theoretical implications for deaf children's reading are discussed
Behavioural and psychological symptoms in the older population without dementia - relationship with socio-demographics, health and cognition
<p>Abstract</p> <p>Background</p> <p>Behavioural and psychological symptoms are associated with dementia, but are also present in a significant number of the older population without dementia. Here we explore the distribution of behavioural and psychological symptoms in the population without dementia, and their relationship with domains and severity of health and cognitive impairment.</p> <p>Methods</p> <p>The Medical Research Council Cognitive Function and Ageing Study is a two-phase longitudinal study of ageing representative of the population aged 65 and over of England and Wales. A subsample of 1781 participants without a study diagnosis of dementia was included in this study. Information on symptoms including depression, apathy, anxiety, feelings of persecution, hallucination, agitated behaviour, elation, irritability, sleep problems, wandering, confabulation and misidentification, cognitive function, health related factors and socio-demographic information was extracted from interviews with participants and knowledgeable informants. Participants were classified according to the Mini-Mental State Examination and by criteria for subtypes of mild cognitive impairment (MCI). The prevalence of behavioural and psychological symptoms and associations with cognitive function, health and socio-demographics was examined. Co-occurrence of symptoms was tested using factor analysis.</p> <p>Results</p> <p>Most symptoms were reported more frequently in those with more severe cognitive impairment. Subjective memory complaints were the strongest independent predictor of reported symptoms, and most were reported more often in those classified as having MCI than in those with cognitive impairments that did not meet the MCI criteria. The pattern of co-occurrence of symptoms is similar to that seen in dementia.</p> <p>Conclusions</p> <p>Our results highlight that behavioural and psychological symptoms are prevalent in the cognitively impaired older population, and partly explain the variation observed in previous cohorts of individuals with MCI. Behavioural and psychological symptoms offer a target for intervention and so are an important consideration in the assessment of cognitively impaired older people.</p
Long-term risk of adverse outcomes according to atrial fibrillation type
Sustained forms of atrial fibrillation (AF) may be associated with a higher risk of adverse outcomes, but few if any long-term studies took into account changes of AF type and co-morbidities over time. We prospectively followed 3843 AF patients and collected information on AF type and co-morbidities during yearly follow-ups. The primary outcome was a composite of stroke or systemic embolism (SE). Secondary outcomes included myocardial infarction, hospitalization for congestive heart failure (CHF), bleeding and all-cause mortality. Multivariable adjusted Cox proportional hazards models with time-varying covariates were used to compare hazard ratios (HR) according to AF type. At baseline 1895 (49%), 1046 (27%) and 902 (24%) patients had paroxysmal, persistent and permanent AF and 3234 (84%) were anticoagulated. After a median (IQR) follow-up of 3.0 (1.9; 4.2) years, the incidence of stroke/SE was 1.0 per 100 patient-years. The incidence of myocardial infarction, CHF, bleeding and all-cause mortality was 0.7, 3.0, 2.9 and 2.7 per 100 patient-years, respectively. The multivariable adjusted (a) HRs (95% confidence interval) for stroke/SE were 1.13 (0.69; 1.85) and 1.27 (0.83; 1.95) for time-updated persistent and permanent AF, respectively. The corresponding aHRs were 1.23 (0.89, 1.69) and 1.45 (1.12; 1.87) for all-cause mortality, 1.34 (1.00; 1.80) and 1.30 (1.01; 1.67) for CHF, 0.91 (0.48; 1.72) and 0.95 (0.56; 1.59) for myocardial infarction, and 0.89 (0.70; 1.14) and 1.00 (0.81; 1.24) for bleeding. In this large prospective cohort of AF patients, time-updated AF type was not associated with incident stroke/SE
Woman-Centered Design through Humanity, Activism, and Inclusion
Women account for over half of the global population, however, continue to be subject to systematic and systemic disadvantage, particularly in terms of access to health and education. At every intersection, where systemic inequality accounts for greater loss of life or limitations on full and healthy living, women are more greatly impacted by those inequalities. The design of technologies is no different, the very definition of technology is historically cast in terms of male activities, and advancements in the field are critical to improve women's quality of life. This article views HCI, a relatively new field, as well positioned to act critically in the ways that technology serve, refigure, and redefine women's bodies. Indeed, the female body remains a contested topic, a restriction to the development of women's health. On one hand, the field of women's health has attended to the medicalization of the body and therefore is to be understood through medical language and knowledge. On the other hand, the framing of issues associated with women's health and people's experiences of and within such system(s) remain problematic for many. This is visible today in, e.g., socio-cultural practices in disparate geographies or medical devices within a clinic or the home. Moreover, the biological body is part of a great unmentionable, i.e., the perils of essentialism. We contend that it is necessary, pragmatically and ethically, for HCI to turn its attention toward a woman-centered design approach. While previous research has argued for the dangers of gender-demarcated design work, we advance that designing for and with women should not be regarded as ghettoizing, but instead as critical to improving women's experiences in bodily transactions, choices, rights, and access to and in health and care. In this article, we consider how and why designing with and for woman matters. We use our design-led research as a way to speak to and illustrate alternatives to designing for and with women within HCI.QC 20200930</p
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