41 research outputs found

    Magnetic order in a metal thiocyanate perovskite-analogue

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    Metal thiocyanate perovskite-analogues are a growing class of materials, but although they contain paramagnetic cations there have been no reports of their magnetic properties. Due to the large separations between the paramagnetic cations, with a shortest through-bond distance of 15.1 Å, these materials might be expected to be good examples of paramagnets. In this communication we investigate the magnetic properties of a metal thiocyanate framework Cr[Bi(SCN)6]·xH2O. We find that Cr[Bi(SCN)6]·xH2O undergoes long-range magnetic order at TN = 4.0(2) K. We use neutron powder diffraction to determine that Cr[Bi(SCN)6]·xH2O has a MnO-type {111}cubic-ordering as its ground state, consistent with frustrated nearest- and next-nearest-neighbour antiferromagnetic interactions. This suggests that appropriate design of metal thiocyanate perovskite-analogue structures may reveal a rich vein of frustrated magnetism

    Variation in the helminth community structure in spiny mice (Acomys dimidiatus) from four montane wadis in the St Katherine region of the Sinai Peninsula in Egypt

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    We compared helminth communities in spiny mice (Acomys dimidiatus) from 4 wadis in the arid montane region of the southern Sinai in Egypt, in a 4-week period in late summer. Total helminth species richness was 14 (8 nematodes, 5 cestodes and 1 acanthocephalan) with 94% of mice carrying at least 1 species and an overall mean species richness of 1.85. The most prevalent parasites were Protospirura muricola (47.8%) and Dentostomella kuntzi (46.3%). One larval cestode, Joyeuxiella rossicum, represents a new host record. The helminth community was dominated by intestinal nematodes (88.7%) of which 58.2% were arthropod-transmitted heteroxenic species. At the component community level, 70% of the worms were recovered from mice in just two wadis (Gharaba and Tlah) and 48.6% of intestinal nematodes were from Wadi Gharaba. Although only 7 species of helminths were recorded from Wadi Gharaba, this site gave the highest Berger-Parker dominance index because P. muricola. P. muricola was also dominant in Wadi El Arbaein whilst Syphacia minuta was the dominant species in Wadis Gebal and Tlah. At the infracommunity level, mean species richness and Brillouin’s index of diversity were highest in Wadi Tlah and lowest in Wadi Gebal, and the former was age dependent. Whilst mice from different wadis differed in the nematodes that were most common, those from Wadi Gharaba carried the highest mean number of worms/mouse. The abundance of P. muricola in particular varied markedly between sites: Wadi Gharaba was distinct as the site showing the highest mean worm burden whereas mice from Wadi Gebal were uninfected. None of the directly transmitted oxyuroid nematodes showed significant variation in abundance between wadis, or host sex or age classes. Overall, the single extrinsic factor in the study, site of capture, was more important than the intrinsic factors in explaining variation in helminth communities in the region. We conclude that in the high mountains of southern Sinai, each wadi is distinct in terms of its rodent parasites, and hence we expect spatially different coevolutionary pressures on their hosts, with resultant variation in life-histories

    Two thymidine hydroxylases differentially regulate the formation of glucosylated DNA at regions flanking polymerase II polycistronic transcription units throughout the genome of Trypanosoma brucei

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    Base J is a hypermodified DNA base localized primarily to telomeric regions of the genome of Trypanosoma brucei. We have previously characterized two thymidine-hydroxylases (TH), JBP1 and JBP2, which regulate J-biosynthesis. JBP2 is a chromatin re-modeling protein that induces de novo J-synthesis, allowing JBP1, a J-DNA binding protein, to stimulate additional J-synthesis. Here, we show that both JBP2 and JBP1 are capable of stimulating de novo J-synthesis. We localized the JBP1- and JBP2-stimulated J by anti-J immunoprecipitation and high-throughput sequencing. This genome-wide analysis revealed an enrichment of base J at regions flanking polymerase II polycistronic transcription units (Pol II PTUs) throughout the T. brucei genome. Chromosome-internal J deposition is primarily mediated by JBP1, whereas JBP2-stimulated J deposition at the telomeric regions. However, the maintenance of J at JBP1-specific regions is dependent on JBP2 SWI/SNF and TH activity. That similar regions of Leishmania major also contain base J highlights the functional importance of the modified base at Pol II PTUs within members of the kinetoplastid family. The regulation of J synthesis/localization by two THs and potential biological function of J in regulating kinetoplastid gene expression is discussed

    A postgraduate curriculum for integrated care : a qualitative exploration of trainee paediatricians and general practitioners' experiences

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    BACKGROUND: Integrated care unites funding, administrative, organisational, service delivery and clinical levels to create connectivity, alignment and collaboration within and between care delivery and prevention sectors. It aims to improve efficiency by avoiding unnecessary duplication of resources. Consequently, implementing integrated care is increasingly important; however, there are many barriers and how we teach healthcare practitioners to work across systems is under-researched. This paper explores an innovative educational curriculum, the Programme for Integrated Child Health (PICH). METHODS: The PICH involved an experiential learning approach supported by taught sessions on specific issues relevant to integrated care. A qualitative study was conducted by interviewing 23 participants using semi-structured one-to-one interviews. Participants included trainees (general practice, paediatrics) and programme mentors. Data was thematically analysed. RESULTS: Results are coded under three main themes: integrated care curriculum components, perceptions of a curriculum addressing integrated care and organisational change, and personal and professional learning. The data highlights the importance of real-world projects, utilising healthcare data, and considering patient perspectives to understand and develop integrated practices. Trainees received guidance from mentors but, more crucially learnt from, with, and about one another. They learnt about the context in which GPs and paediatricians work and developed a deeper understanding through which integrated services could be meaningfully developed. CONCLUSIONS: This study explored participants' experiences and can be taken forward by educationalists to design curricula to better prepare healthcare practitioners to work collaboratively. The emergence of integrated care brings about challenges for traditional pedagogical approaches as learners have to re-align their discipline-specific approaches with evolving healthcare structures. PICH demonstrated that trainees acquired knowledge through real-word projects and experiential learning; and that this facilitated integration, empowering doctors to become leaders of organisational change. However, there are also many challenges of implementing integrated curricula which need to be addressed, including breaking down professional silos and integrating resourceful healthcare. This study begins to demonstrate the ability of an integrated curriculum to support trainees to work collaboratively, but further work is needed to develop the wider efficacy of the programme incorporating other professional groups, and to assess its longer term impact

    Time to Switch to Second-line Antiretroviral Therapy in Children With Human Immunodeficiency Virus in Europe and Thailand.

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    Background: Data on durability of first-line antiretroviral therapy (ART) in children with human immunodeficiency virus (HIV) are limited. We assessed time to switch to second-line therapy in 16 European countries and Thailand. Methods: Children aged <18 years initiating combination ART (≥2 nucleoside reverse transcriptase inhibitors [NRTIs] plus nonnucleoside reverse transcriptase inhibitor [NNRTI] or boosted protease inhibitor [PI]) were included. Switch to second-line was defined as (i) change across drug class (PI to NNRTI or vice versa) or within PI class plus change of ≥1 NRTI; (ii) change from single to dual PI; or (iii) addition of a new drug class. Cumulative incidence of switch was calculated with death and loss to follow-up as competing risks. Results: Of 3668 children included, median age at ART initiation was 6.1 (interquartile range (IQR), 1.7-10.5) years. Initial regimens were 32% PI based, 34% nevirapine (NVP) based, and 33% efavirenz based. Median duration of follow-up was 5.4 (IQR, 2.9-8.3) years. Cumulative incidence of switch at 5 years was 21% (95% confidence interval, 20%-23%), with significant regional variations. Median time to switch was 30 (IQR, 16-58) months; two-thirds of switches were related to treatment failure. In multivariable analysis, older age, severe immunosuppression and higher viral load (VL) at ART start, and NVP-based initial regimens were associated with increased risk of switch. Conclusions: One in 5 children switched to a second-line regimen by 5 years of ART, with two-thirds failure related. Advanced HIV, older age, and NVP-based regimens were associated with increased risk of switch

    The characterization of intraepithelial lymphocytes, lamina propria leukocytes, and isolated lymphoid follicles in the large intestine of mice infected with the intestinal nematode parasite Trichuris muris

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    Abstract Despite a growing understanding of the role of cytokines in immunity to the parasitic helminth Trichuris muris, the local effector mechanism culminating in the expulsion of worms from the large intestine is not known. We used flow cytometry and immunohistochemistry to characterize the phenotype of large intestinal intraepithelial lymphocytes (IEL) and lamina propria leukocytes (LPL) from resistant and susceptible strains of mouse infected with T. muris. Leukocytes accumulated in the epithelium and lamina propria after infection, revealing marked differences between the different strains of mouse. In resistant mice, which mount a Th2 response, the number of infiltrating CD4+, CD8+, B220+, and F4/80+ IEL and LPL was generally highest around the time of worm expulsion from the gut, at which point the inflammation was dominated by CD4+ IEL and F4/80+ LPL. In contrast, in susceptible mice, which mount a Th1 response, the number of IEL and LPL increased more gradually and was highest after a chronic infection had developed. At this point, CD8+ IEL and F4/80+ LPL were predominant. Therefore, this study reveals the local immune responses underlying the expulsion of worms or the persistence of a chronic infection in resistant and susceptible strains of mouse, respectively. In addition, for the first time, we illustrate isolated lymphoid follicles in the large intestine, consisting of B cells interspersed with CD4+ T cells and having a central zone of rapidly proliferating cells. Furthermore, we demonstrate the organogenesis of these structures in response to T. muris infection.</jats:p
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