Modular Acquisition and Stimulation System for Timestamp-Driven Neuroscience Experiments

Dedicated systems are fundamental for neuroscience experimental protocols that require timing determinism and synchronous stimuli generation. We developed a data acquisition and stimuli generator system for neuroscience research, optimized for recording timestamps from up to 6 spiking neurons and entirely specified in a high-level Hardware Description Language (HDL). Despite the logic complexity penalty of synthesizing from such a language, it was possible to implement our design in a low-cost small reconfigurable device. Under a modular framework, we explored two different memory arbitration schemes for our system, evaluating both their logic element usage and resilience to input activity bursts. One of them was designed with a decoupled and latency insensitive approach, allowing for easier code reuse, while the other adopted a centralized scheme, constructed specifically for our application. The usage of a high-level HDL allowed straightforward and stepwise code modifications to transform one architecture into the other. The achieved modularity is very useful for rapidly prototyping novel electronic instrumentation systems tailored to scientific research.Comment: Preprint submitted to ARC 2015. Extended: 16 pages, 10 figures. The final publication is available at link.springer.co

Delays in access to care for abortion-related complications: the experience of women in Northeast Brazil.

Around 18 million unsafe abortions occur in low and middle-income countries and are associated with numerous adverse consequences to women's health. The time taken by women with complications to reach facilities where they can receive appropriate post-abortion care can influence the risk of death and the extent of further complications. All women aged 18+ admitted for abortion complications to public-sector hospitals in three capital cities in the Northeastern Brazil between August-December 2010 were interviewed; medical records were extracted (N = 2,804). Nearly all women (94%) went straight to a health facility, mainly to a hospital (76.6%); the rest had various care-seeking paths, with a quarter visiting 3+ hospitals. Women waited 10 hours on average before deciding to seek care. 29% reported difficulties in starting to seek care, including facing challenges in organizing childcare, a companion or transport (17%) and fear/stigma (11%); a few did not initially recognize they needed care (0.4%). The median time taken to arrive at the ultimate facility was 36 hours. Over a quarter of women reported experiencing difficulties being admitted to a hospital, including long waits (15%), only being attended after pregnant women (8.9%) and waiting for a bed (7.4%). Almost all women (90%) arrived in good condition, but those with longer delays were more likely to have (mild or severe) complications. In Brazil, where access to induced abortion is restricted, women face numerous difficulties receiving post-abortion care, which contribute to delay and influence the severity of post-abortion complications

Sialic Acid Glycobiology Unveils Trypanosoma cruzi Trypomastigote Membrane Physiology.

Trypanosoma cruzi, the flagellate protozoan agent of Chagas disease or American trypanosomiasis, is unable to synthesize sialic acids de novo. Mucins and trans-sialidase (TS) are substrate and enzyme, respectively, of the glycobiological system that scavenges sialic acid from the host in a crucial interplay for T. cruzi life cycle. The acquisition of the sialyl residue allows the parasite to avoid lysis by serum factors and to interact with the host cell. A major drawback to studying the sialylation kinetics and turnover of the trypomastigote glycoconjugates is the difficulty to identify and follow the recently acquired sialyl residues. To tackle this issue, we followed an unnatural sugar approach as bioorthogonal chemical reporters, where the use of azidosialyl residues allowed identifying the acquired sugar. Advanced microscopy techniques, together with biochemical methods, were used to study the trypomastigote membrane from its glycobiological perspective. Main sialyl acceptors were identified as mucins by biochemical procedures and protein markers. Together with determining their shedding and turnover rates, we also report that several membrane proteins, including TS and its substrates, both glycosylphosphatidylinositol-anchored proteins, are separately distributed on parasite surface and contained in different and highly stable membrane microdomains. Notably, labeling for α(1,3)Galactosyl residues only partially colocalize with sialylated mucins, indicating that two species of glycosylated mucins do exist, which are segregated at the parasite surface. Moreover, sialylated mucins were included in lipid-raft-domains, whereas TS molecules are not. The location of the surface-anchored TS resulted too far off as to be capable to sialylate mucins, a role played by the shed TS instead. Phosphatidylinositol-phospholipase-C activity is actually not present in trypomastigotes. Therefore, shedding of TS occurs via microvesicles instead of as a fully soluble form