174 research outputs found

    Transcriptome Analysis of an Aedes albopictus Cell Line Single- and Dual-Infected with Lammi Virus and WNV

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    Understanding the flavivirus infection process in mosquito hosts is important and fundamental in the search for novel control strategies that target the mosquitoes' ability to carry and transmit pathogenic arboviruses. A group of viruses known as insect-specific viruses (ISVs) has been shown to interfere with the infection and replication of a secondary arbovirus infection in mosquitoes and mosquito-derived cell lines. However, the molecular mechanisms behind this interference are unknown. Therefore, in the present study, we infected the Aedes albopictus cell line U4.4 with either the West Nile virus (WNV), the insect-specific Lammi virus (LamV) or an infection scheme whereby cells were pre-infected with LamV 24 h prior to WNV challenge. The qPCR analysis showed that the dual-infected U4.4 cells had a reduced number of WNV RNA copies compared to WNV-only infected cells. The transcriptome profiles of the different infection groups showed a variety of genes with altered expression. WNV-infected cells had an up-regulation of a broad range of immune-related genes, while in LamV-infected cells, many genes related to stress, such as different heat-shock proteins, were up-regulated. The transcriptome profile of the dual-infected cells was a mix of up- and down-regulated genes triggered by both viruses. Furthermore, we observed an up-regulation of signal peptidase complex (SPC) proteins in all infection groups. These SPC proteins have shown importance for flavivirus assembly and secretion and could be potential targets for gene modification in strategies for the interruption of flavivirus transmission by mosquitoes

    The Social context of motorcycle riding and the key determinants influencing rider behavior: A qualitative investigation

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    Objective: Given the increasing popularity of motorcycle riding and heightened risk of injury or death associated with being a rider, this study explored rider behaviour as a determinant of rider safety and, in particular, key beliefs and motivations which influence such behaviour. To enhance the effectiveness of future education and training interventions, it is important to understand riders’ own views about what influences how they ride. Specifically, this study sought to identify key determinants of riders’ behaviour in relation to the social context of riding including social and identity-related influences relating to the group (group norms and group identity) as well as the self (moral/personal norm and self-identity). ----- ----- Method: Qualitative research was undertaken via group discussions with motorcycle riders (n = 41). Results: The findings revealed that those in the group with which one rides represent an important source of social influence. Also, the motorcyclist (group) identity was associated with a range of beliefs, expectations, and behaviours considered to be normative. Exploration of the construct of personal norm revealed that riders were most cognizant of the “wrong things to do” when riding; among those issues raised was the importance of protective clothing (albeit for the protection of others and, in particular, pillion passengers). Finally, self-identity as a motorcyclist appeared to be important to a rider’s self-concept and was likely to influence their on-road behaviour. ----- ----- Conclusion: Overall, the insight provided by the current study may facilitate the development of interventions including rider training as well as public education and mass media messages. The findings suggest that these interventions should incorporate factors associated with the social nature of riding in order to best align it with some of the key beliefs and motivations underpinning riders’ on-road behaviours

    Flipping exciton angular momentum with chiral phonons in MoSe2_2/WSe2_2 heterobilayers

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    Identifying quantum numbers to label elementary excitations is essential for the correct description of light-matter interaction in solids. In monolayer semiconducting transition metal dichalcogenides (TMDs) such as MoSe2_2 or WSe2_2, most optoelectronic phenomena are described well by labelling electron and hole states with the spin projection along the normal to the layer (Sz_z). In contrast, for WSe2_2/MoSe2_2 interfaces recent experiments show that taking Sz_z as quantum number is not a good approximation, and spin mixing needs to be always considered. Here we argue that the correct quantum number for these systems is not Sz_z, but the zz-component of the total angular momentum -- Jz_z = Lz_z + Sz_z -- associated to the C3_3 rotational lattice symmetry, which assumes half-integer values corresponding modulo 3 to distinct states. We validate this conclusion experimentally through the observation of strong intervalley scattering mediated by chiral optical phonons that -- despite carrying angular momentum 1 -- cause resonant intervalley transitions of excitons, with an angular momentum difference of 2.Comment: are welcom

    Oral fexinidazole for stage 1 or early stage 2 African Trypanosoma brucei gambiense trypanosomiasis: a prospective, multicentre, open-label, cohort study

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    BACKGROUND: Staging and treatment of human African trypanosomiasis caused by Trypanosoma brucei gambiense (g-HAT) required lumbar puncture to assess cerebrospinal fluid (CSF) and intravenous drugs that cross the blood-brain barrier for late-stage infection. These procedures are inconvenient in rural health systems of disease-endemic countries. A pivotal study established fexinidazole as the first oral monotherapy to be effective against non-severe stage 2 g-HAT. We aimed to assess the safety and efficacy of fexinidazole in early g-HAT. METHODS: In this prospective, multicentre, open-label, single-arm cohort study, patients with stage 1 or early stage 2 g-HAT were recruited from eight treatment centres in the Democratic Republic of the Congo. Primary inclusion criteria included being older than 15 years, being able to ingest at least one complete meal per day (or at least one sachet of Plumpy'Nut®), a Karnofsky score higher than 50, evidence of trypanosomes in the blood or lymph but no evidence of trypanosomes in the CSF, willingness to be admitted to hospital to receive treatment, having a permanent address, and being able to comply with the follow-up visit schedule. Exclusion criteria included severe malnutrition, inability to take medication orally, pregnant or breastfeeding women, any clinically important medical condition that could jeopardise patient safety or participation in the study, severely deteriorated general status, any contraindication to imidazole drugs, HAT treatment in the past 2 years, previous enrolment in the study or previous intake of fexinidazole, abnormalities on electrocardiogram that did not return to normal in pretreatment repeated assessments or were considered clinically important, QT interval corrected using Fridericia's formula of at least 450 ms, and patients not tested for malaria or not having received appropriate treatment for malaria or for soil-transmitted helminthiasis. Patients were classified into stage 1 or early stage 2 g-HAT groups following evidence of trypanosomes in the blood, lymph, and absence in CSF, and using white-blood-cell count in CSF. Patients received 1800 mg fexinidazole once per day on days 1-4 then 1200 mg fexinidazole on days 5-10. Patients were observed for approximately 19 months in total. Study participants were followed up on day 5 and day 8 during treatment, at end of treatment on day 11, at end of hospitalisation on days 11-18, at week 9 for a subset of patients, and after 6 months, 12 months, and 18 months. The primary endpoint was treatment success at 12 months. Safety was assessed through routine monitoring. Analyses were done in the intention-to-treat population. The acceptable success rate was defined as treatment efficacy in more than 80% of patients. This study is completed and registered with ClinicalTrials.gov (NCT02169557). FINDINGS: Patients were enrolled between April 30, 2014, and April 25, 2017. 238 patients were recruited: 195 (82%) patients with stage 1 g-HAT and 43 (18%) with early stage 2 g-HAT. 189 (97%) of 195 patients with stage 1 g-HAT and 41 (95%) of 43 patients with early stage 2 g-HAT were finally included and completed the 10 day treatment period. Three patients with stage 1 g-HAT died after the 10 day treatment period and before the 12 month primary follow-up visit, considered as treatment failure and were withdrawn from the study. Treatment was effective at 12 months for 227 (99%) of 230 patients (95% CI 96·2-99·7): 186 (98%) of 189 patients (95·4-99·7) with stage 1 and 41 (100%) of 41 patients (91·4-100·0) with early stage 2, indicating that the primary study endpoint was met. No new safety issues were observed. The most frequent adverse events were headache and vomiting. In total, 214 (93%) of 230 patients had treatment-emergent adverse events, mainly common-terminology criteria for adverse events grades 1 to 3. None led to treatment discontinuation. INTERPRETATION: Fexinidazole is a valuable first-line treatment option in the early stages of g-HAT. FUNDING: Through the Drugs for Neglected Diseases initiative: the Bill & Melinda Gates Foundation, the Republic and Canton of Geneva (Switzerland), the Dutch Ministry of Foreign Affairs (also known as DGIS; Netherlands), the Norwegian Agency for Development Cooperation (also known as Norad; Norway), the Federal Ministry of Education and Research (also known as BMBF) through KfW (Germany), the Brian Mercer Charitable Trust (UK), and other private foundations and individuals from the HAT campaign

    Safety and efficacy of oral fexinidazole in children with gambiense human African trypanosomiasis: a multicentre, single-arm, open-label, phase 2-3 trial

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    BACKGROUND: Fexinidazole has been reported as an effective oral monotherapy against non-severe gambiense human African trypanosomiasis in a recent trial in adults. We aimed to assess the safety and efficacy of fexinidazole in children across all disease stages of gambiense human African trypanosomiasis. METHODS: We did a multicentre, single-arm, open-label, phase 2-3 trial at eight district hospitals in the Democratic Republic of the Congo. We recruited children with a Karnofsky score of more than 50, those aged 6 years to younger than 15 years, weighing 20 kg or more, and with confirmed gambiense human African trypanosomiasis (any stage). Children weighing 20 kg or more and less than 35 kg received oral fexinidazole of 1200 mg (two x 600 mg tablets) once per day for 4 days (days 1-4) followed by 600 mg (one x 600 mg tablet) once per day for 6 days (days 5-10). Children weighing 35 kg or more received oral fexinidazole of 1800 mg (three x 600 mg tablets) once per day for 4 days (days 1-4), followed by 1200 mg (two x 600 mg tablets) once per day for 6 days (days 5-10). The primary endpoint was fexinidazole treatment success rate 12 months after end of treatment. A rate greater than 80% was deemed acceptable and a target value of 92% was aimed for. Safety was assessed through routine monitoring. This study is completed and registered with ClinicalTrials.gov, number NCT02184689. FINDINGS: Between May 3, 2014, and Nov 22, 2016, we screened a total of 130 paediatric patients, of whom 125 (96%) received at least one dose of fexinidazole. All 125 patients (69 [55%] patients with stage 1, 19 [15%] with early stage 2, and 37 [30%] with late stage 2 gambiense human African trypanosomiasis) completed the 10-day treatment. Treatment success rate at 12 months was 97.6% (95% CI 93.1-99.5; 122 of 125 patients). The primary endpoint was met and the targeted value of 92% was exceeded. Treatment success at 12 months was elevated across all disease stages: 98.6% (95% CI 92.2-99.9; 68 of 69 patients) in stage 1, 94.7% (74.0-99.9; 18 of 19 patients) in early stage 2, and 97.3% (85.8-99.9; 36 of 37 patients) in late stage 2 gambiense human African trypanosomiasis. No new safety issues were observed beyond those found in adult trials. Overall, 116 (93%) of 125 patients reported 586 treatment-emergent adverse events, mainly mild or moderate. The most frequently reported treatment-emergent adverse events of interest during hospital admission were vomiting (86 [69%] of 125) and headache (41 [33%]). Seven (6%) of 125 patients had severe malaria, which was often accompanied by anaemia that was unrelated to fexinidazole. One patient died following dyspnoea and injury due to traumatic aggression 172 days after end of treatment, which was considered unrelated to fexinidazole or gambiense human African trypanosomiasis. INTERPRETATION: Oral fexinidazole is a safe and effective first-line treatment option across all gambiense human African trypanosomiasis disease stages in paediatric patients. FUNDING: Through the Drugs for Neglected Diseases initiative: the Bill & Melinda Gates Foundation (USA), the Republic and Canton of Geneva (Switzerland), the Dutch Ministry of Foreign Affairs (Netherlands), the Norwegian Agency for Development Cooperation (Norway), the Federal Ministry of Education and Research through KfW (Germany), the Brian Mercer Charitable Trust (UK), and other private foundations and individuals from the human African trypanosomiasis campaign. TRANSLATION: For the French translation of the abstract see Supplementary Materials section

    Seamless Gene Tagging by Endonuclease-Driven Homologous Recombination

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    Gene tagging facilitates systematic genomic and proteomic analyses but chromosomal tagging typically disrupts gene regulatory sequences. Here we describe a seamless gene tagging approach that preserves endogenous gene regulation and is potentially applicable in any species with efficient DNA double-strand break repair by homologous recombination. We implement seamless tagging in Saccharomyces cerevisiae and demonstrate its application for protein tagging while preserving simultaneously upstream and downstream gene regulatory elements. Seamless tagging is compatible with high-throughput strain construction using synthetic genetic arrays (SGA), enables functional analysis of transcription antisense to open reading frames and should facilitate systematic and minimally-invasive analysis of gene functions

    FI on-line chemiluminescence reaction for determination of MCPA in water samples

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    This paper reports an economic, simple, and rapid FI-CL method for the determination of MCPA. This method requires simple instrumentation and it is fast enough to be used in routine analyses. A chemiluminescence signal is generated by reaction between photodegraded MCPA and ferricyanide solution in alkaline medium. All physical and chemical parameters in the flow injection chemiluminescence system were optimized in the experimental setting. To eliminate interference, a solid-phase extraction stage with SDB-1 cartridges and ethanol elution is applied. The signal-MCPA concentration relation is linear in concentration intervals between 0.0015 and 0.6 ¿g¿mL -1. The calibration lines are statistically similar in different working conditions: standards with ethanol without extraction and standards with ethanol and extraction, allowing standards to be excluded from the extraction step, which simplifies the process. The detection limit (DL) is 0.5 ng¿mL -1, which is the same order as the maximum limit established in legislation regarding pesticide limits in water destined for human consumption. A DL of 0.13 ng¿mL -1 can be reached if a sample of 100 mL is preconcentrated. The interday variance coefficient is 3% and the sample throughput is 90 h -1. The water analysis method is efficient with relative error percentages lower than 5% with respect to the added concentration. © 2011 Springer-Verlag.Authors acknowledge to the "Ministerio de Educacion y Ciencia" of Spain and FEDER funds for financial support (Project CTM2006-11991)Torres Cartas, S.; Gómez Benito, C.; Meseguer-Lloret, S. (2012). FI on-line chemiluminescence reaction for determination of MCPA in water samples. Analytical and Bioanalytical Chemistry. 402:1289-1296. https://doi.org/10.1007/s00216-011-5567-1S12891296402Navarro JS (2008) Utilización de plaguicidas en las asociaciones de tratamientos integrados en agricultura en la región de Murcia. Consejería de Sanidad Región de MurciaBarceló D, Hennion MC (1997) Trace determination of pesticide and their degradation products in water. Elsevier, AmsterdamKöck M, Farré M, Martínez E, Gajda-Schrantz K, Ginebreda A, Navarro A, López de Alda M, Barceló D (2010) J Hydrol 383(1–2):73–82Woudneh MB, Sekela M, Tuominen T, Gledhill M (2007) J Chromatogr A 1139(1):121–129Laganà A, Bacaloni A, De-Leva I, Faberi A, Fago G, Marino A (2002) Anal Chim Acta 462:187–198Comoretto L, Arfib B, Chiron S (2007) Sci Total Environ 380(1–3):124–132Kuster M, de Alda MJL, Barata C, Raldá D, Barceló D (2008) Talanta 75(2):390–401Kuster M, de Alda MJL, Hernando MD, Petrovic M, Martín-Alonso J, Barceló D (2008) J Hydrol 358(1–2):112–123Gervais G, Brosillon S, Laplanche A, Helen C (2008) J Chromatogr A 1202(2):163–172Housari F, Höhener P, Chiron S (2011) Sci Total Environ 409(3):582–587Delhomme O, Raeppel C, Briand O, Millet M (2011) Anal Bioanal Chem 399:1325–1334Royal decree 140/2003, 7th of February that establishes the health criteria for the water quality for human consumption. (BOE 21 February 2003)von-der-Ohe PC, Dulio V, Slobodnik J, de-Deckere E, Köhne R, Ebert RU, Ginebreda A, de-Cooman de-Cooman W, Schüürmann G, Brack W (2011) Sci Total Environ 409(11):2064–2077Horwitz W (ed) (2000) Official methods of analysis of AOAC International, 17th edn. AOAC International, GaithersburgMoret S, Sánchez JM, Salvadó V, Hidalgo M (2005) J Chromatogr A 1099(1–2):55–63Tran ATK, Hyne RV, Doble P (2007) Chemosphere 67(5):944–953Long F, Shi HC, He M, Zhu AN (2008) Biosens Bioelectron 23:1361–1366Meulenberg EP, Stoks PG (1995) Anal Chim Acta 311:407–413Chuang JC, Van Emon JM, Durnford J, Thomas K (2005) Talanta 67:658–666Boro RC, Kaushal J, Nangia Y, Wangoo N, Bhashi A, Suri CR (2011) Analyst 136(10):2125–2130Eremin SA, Laassis P, Aaron JJ (1996) Talanta 43:295–301Almansa-López EM, García-Campaña AM, Aaron JJ, Cuadros-Rodriguez L (2003) Talanta 60:355–367García LF, Eremin S, Aaron JJ (1996) Anal Lett 29(8):1447–1461García-Campaña AM, Aaron JJ, Bosque-Sendra JM (2002) Luminescence 17:285–287Lara FJ, García-Campaña AM, Aaron JJ (2010) Anal Chim Acta 679:17–30López-Paz J, Catalá-Icardo M (2011) Anal Lett 44(1–3):146–175Mbaye M, Gaye-Seye M, Aaron JJ, Coly A, Tine A (2011) Anal Bioanal Chem 400(2):403–410López-Paz JL, Catalá-Icardo M, Antón-Garrido B (2009) Anal Bioanal Chem 394:1073–1079López-Paz J, Catalá-Icardo M (2008) Anal Chim Acta 625(2):173–179Chen X, Lin Z, Cai Z, Chen X, Wang X (2008) Talanta 76(5):1083–1087Meseguer-Lloret S, Torres-Cartas S, Gómez-Benito M (2010) Anal Bioanal Chem 398:3175–3182Catalá-Icardo M, Martínez-Calatayud J (2008) Crit Rev Anal Chem 38(2):118–13
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