279 research outputs found
Cationic exchange in nanosized ZnFe2O4 spinel revealed by experimental and simulated near-edge absorption structure
The non-equilibrium cation site occupancy in nanosized zinc ferrites (6-13
nm) with different degree of inversion (0.2 to 0.4) was investigated using Fe
and Zn K-edge x-ray absorption spectroscopy XANES and EXAFS, and magnetic
measurements. The very good agreement between experimental and ab-initio
calculations on the Zn K-edge XANES region clearly show the large
Zn2+(A)--Zn2+[B] transference that takes place in addition to the
well-identified Fe3+[B]--Fe3+(A) one, without altering the long-range
structural order. XANES spectra features as a function of the spinel inversion
were shown to depend on the configuration of the ligand shells surrounding the
absorbing atom. This XANES approach provides a direct way to sense cationic
inversion in these spinel compounds. We also demonstrated that a mechanical
crystallization takes place on nanocrystalline spinel that causes an increase
of both grain and magnetic sizes and, simultaneously, generates a significant
augment of the inversion.Comment: 5 pages, 5 eps figures, uses revtex4, corrected table
Citizen science provides a reliable and scalable tool to track disease-carrying mosquitoes
Recent outbreaks of Zika, chikungunya and dengue highlight the importance of better understanding the spread of disease-carrying mosquitoes across multiple spatio-temporal scales. Traditional surveillance tools are limited by jurisdictional boundaries and cost constraints. Here we show how a scalable citizen science system can solve this problem by combining citizen scientists'' observations with expert validation and correcting for sampling effort. Our system provides accurate early warning information about the Asian tiger mosquito (Aedes albopictus) invasion in Spain, well beyond that available from traditional methods, and vital for public health services. It also provides estimates of tiger mosquito risk comparable to those from traditional methods but more directly related to the human-mosquito encounters that are relevant for epidemiological modelling and scalable enough to cover the entire country. These results illustrate how powerful public participation in science can be and suggest citizen science is positioned to revolutionize mosquito-borne disease surveillance worldwide
Gold(I)-Catalyzed Cycloisomerization/Hetero-Diels-Alder Reaction/Ring Opening Cascade to Functionalized Cyclopentadienes
First detection of Aedes japonicus in Spain: An unexpected finding triggered by citizen science
Background: Aedes japonicus is an invasive vector mosquito from Southeast Asia which has been spreading across central Europe since the year 2000. Unlike the Asian Tiger mosquito (Aedes albopictus) present in Spain since 2004, there has been no record of Ae. japonicus in the country until now.
Results: Here, we report the first detection of Ae. japonicus in Spain, at its southernmost location in Europe. This finding was triggered by the citizen science platform Mosquito Alert. In June 2018, a citizen sent a report via the Mosquito Alert app from the municipality of Siero in the Asturias region (NW Spain) containing pictures of a female mosquito compatible with Ae. japonicus. Further information was requested from the participant, who subsequently provided several larvae and adults that could be classified as Ae. japonicus. In July, a field mission confirmed its presence at the original site and in several locations up to 9 km away, suggesting a long-time establishment. The strong media impact in Asturias derived from the discovery raised local participation in the Mosquito Alert project, resulting in further evidence from surrounding areas.
Conclusions: Whilst in the laboratory Ae. japonicus is a competent vector for several mosquito-borne pathogens, to date only West Nile virus is a concern based on field evidence. Nonetheless, this virus has yet not been detected in Asturias so the vectorial risk is currently considered low. The opportunity and effectiveness of combining citizen-sourced data to traditional surveillance methods are discussed
Relational Goods and Endurance of Voluntary Associational Participation: The Mapuche Indigenous Case in Santiago de Chile.
In this article, I analyse the reasons for sustaining membership in voluntary
ethnic associations of Mapuche people living in Santiago de Chile. By following a relational goods approach, I suggest that the constructed nature of ethnicity leads the Mapuche to create and join ethnic associations in an urban milieu. This study reveals that the main motivations for sustaining an active associational engagement in Santiago are based on three accounts: identity recovery struggle, leaving an identity legacy and bonding with their ethnic peers; all of these identified as relational goods. This investigation is based on an eight-month ethnographic fieldwork conducted in Santiago.This work was supported by the University of Cambridge Sociology Graduate Education Committee (GEC) Fieldwork Funding; Newnham College, University of Cambridge Fieldwork Grant; and under the Programme Becas de Doctorado con Acuerdo Bilateral en el Extranjero Becas Chile-Cambridge (Grant Fondecyt: N° 84140015)
Preclinical development of a vaccine against oligomeric alpha-synuclein based on virus-like particles
Parkinson's disease (PD) is a progressive and currently incurable
neurological disorder characterised by the loss of midbrain dopaminergic
neurons and the accumulation of aggregated alpha-synuclein (a-syn).
Oligomeric a-syn is proposed to play a central role in spreading protein
aggregation in the brain with associated cellular toxicity contributing
to a progressive neurological decline. For this reason, a-syn oligomers
have attracted interest as therapeutic targets for neurodegenerative
conditions such as PD and other alpha-synucleinopathies. In addition to
strategies using small molecules, neutralisation of the toxic oligomers
by antibodies represents an attractive and highly specific strategy for
reducing disease progression. Emerging active immunisation approaches
using vaccines are already being trialled to induce such antibodies.
Here we propose a novel vaccine based on the RNA bacteriophage (Qbeta)
virus-like particle conjugated with short peptides of human a-syn. High
titres of antibodies were successfully and safely generated in wild-type
and human a-syn over-expressing (SNCA-OVX) transgenic mice
following vaccination. Antibodies from vaccine candidates targeting the
C-terminal regions of a-syn were able to recognise Lewy bodies, the
hallmark aggregates in human PD brains. Furthermore, antibodies
specifically targeted oligomeric and aggregated a-syn as they exhibited
100 times greater affinity for oligomeric species over monomer a-syn
proteins in solution. In the SNCA-OVX transgenic mice used, vaccination
was, however, unable to confer significant changes to oligomeric a-syn
bioburden. Similarly, there was no discernible effect of vaccine
treatment on behavioural phenotype as compared to control groups. Thus,
antibodies specific for oligomeric a-syn induced by vaccination were
unable to treat symptoms of PD in this particular mouse model.</p
Mitochondrial DNA disturbances and deregulated expression of oxidative phosphorylation and mitochondrial fusion proteins in sporadic inclusion body myositis
Sporadic inclusion body myositis (sIBM) is one of the most common myopathies in elderly people. Mitochondrial abnormalities at the histological level are present in these patients. We hypothesize that mitochondrial dysfunction may play a role in disease aetiology. We took the following measurements of muscle and peripheral blood mononuclear cells (PBMCs) from 30 sIBM patients and 38 age-and gender-paired controls: mitochondrial DNA (mtDNA) deletions, amount of mtDNA and mtRNA, mitochondrial protein synthesis, mitochondrial respiratory chain (MRC) complex I and IV enzymatic activity, mitochondrial mass, oxidative stress and mitochondrial dynamics (mitofusin 2 and optic atrophy 1 levels). Depletion of mtDNA was present in muscle from sIBM patients and PBMCs showed deregulated expression of mitochondrial proteins in oxidative phosphorylation. MRC complex IV/citrate synthase activity was significantly decreased in both tissues and mitochondrial dynamics were affected in muscle. Depletion of mtDNA was significantly more severe in patients with mtDNA deletions, which also presented deregulation of mitochondrial fusion proteins. Imbalance in mitochondrial dynamics in muscle was associated with increased mitochondrial genetic disturbances (both depletion and deletions), demonstrating that proper mitochondrial turnover is essential for mitochondrial homoeostasis and muscle function in these patients
Perceived discrimination amongst the indigenous Mapuche people in Chile : some comparisons with Australia
With similar settler-colonial histories having left them occupying the position of marginalized minority groups, indigenous people in Chile and Australia are struggling to assert their rights and retain their cultures. Research in each location suggests that there is widespread prejudice and discrimination against them, even though the mainstream society sees itself as tolerant and harmonious. This paper reports on a study in which thirty Mapuche people in Chile were interviewed about their perceptions of discrimination against them. Their responses were systematically analysed using a taxonomy of racist experiences established in a study of Aborigines in Australia. Like indigenous Australians, the Mapuche people of Chile reported that they experience extensive discrimination in all areas of life. These findings are discussed with respect to the issues related to relationships between settlers and colonized communities.<br /
Inorganic base-catalyzed formation of antivirally active N-substituted benzamides from α-amido sulfones and N-nucleophile
Loss of MicroRNA-7 Regulation Leads to α-Synuclein Accumulation and Dopaminergic Neuronal Loss In Vivo
Abnormal alpha-synuclein (α-synuclein) expression and aggregation is a key characteristic of Parkinson's disease (PD). However, the exact mechanism(s) linking α-synuclein to the other central feature of PD, dopaminergic neuron loss, remains unclear. Therefore, improved cell and in vivo models are needed to investigate the role of α-synuclein in dopaminergic neuron loss. MicroRNA-7 (miR-7) regulates α-synuclein expression by binding to the 3' UTR of the Synuclein Alpha Non A4 Component of Amyloid Precursor (SNCA) gene and inhibiting its translation. We show that miR-7 is decreased in the substantia nigra of patients with PD and, therefore, may play an essential role in the regulation of α-synuclein expression. Furthermore, we have found that lentiviral-mediated expression of miR-7 complementary binding sites to stably induce a loss of miR-7 function results in an increase in α-synuclein expression in vitro and in vivo. We have also shown that depletion of miR-7 using a miR-decoy produces a loss of nigral dopaminergic neurons accompanied by a reduction of striatal dopamine content. These data suggest that miR-7 has an important role in the regulation of α-synuclein and dopamine physiology and may provide a new paradigm to study the pathology of PD
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