199 research outputs found
The smfBox is an open-source platform for single-molecule FRET
Single-molecule Förster Resonance Energy Transfer (smFRET) is a powerful technique capable of resolving both relative and absolute distances within and between structurally dynamic biomolecules. High instrument costs, and a lack of open-source hardware and acquisition software have limited smFRET’s broad application by non-specialists. Here, we present the smfBox, a cost-effective confocal smFRET platform, providing detailed build instructions, open-source acquisition software, and full validation, thereby democratising smFRET for the wider scientific community
Deep analysis of CD4 T cells in the rhesus CNS during SIV infection
Virologic suppression with antiretroviral therapy (ART) has significantly improved health outcomes for people living with HIV, yet challenges related to chronic inflammation in the central nervous system (CNS)—known as Neuro-HIV- persist. As primary targets for HIV-1 with the ability to survey and populate the CNS and interact with myeloid cells to co-ordinate neuroinflammation, CD4 T cells are pivotal in Neuro-HIV. Despite their importance, our understanding of CD4 T cell distribution in virus-targeted CNS tissues, their response to infection, and potential recovery following initiation of ART remain limited. To address these gaps, we studied ten SIVmac251-infected rhesus macaques using an ART regimen simulating suboptimal adherence. We evaluated four macaques during the acute phase pre-ART and six during the chronic phase. Our data revealed that HIV target CCR5+ CD4 T cells inhabit both the brain parenchyma and adjacent CNS tissues, encompassing choroid plexus stroma, dura mater, and the skull bone marrow. Aligning with the known susceptibility of CCR5+ CD4 T cells to viral infection and their presence within the CNS, high levels of viral RNA were detected in the brain parenchyma and its border tissues during acute SIV infection. Single-cell RNA sequencing of CD45+ cells from the brain revealed colocalization of viral transcripts within CD4 clusters and significant activation of antiviral molecules and specific effector programs within T cells, indicating CNS CD4 T cell engagement during infection. Acute infection led to marked imbalance in the CNS CD4/CD8 ratio which persisted into the chronic phase. These observations underscore the functional involvement of CD4 T cells within the CNS during SIV infection, enhancing our understanding of their role in establishing CNS viral presence. Our findings offer insights for potential T cell-focused interventions while underscoring the challenges in eradicating HIV from the CNS, particularly in the context of sub-optimal ART
Possible origins of macroscopic left-right asymmetry in organisms
I consider the microscopic mechanisms by which a particular left-right (L/R)
asymmetry is generated at the organism level from the microscopic handedness of
cytoskeletal molecules. In light of a fundamental symmetry principle, the
typical pattern-formation mechanisms of diffusion plus regulation cannot
implement the "right-hand rule"; at the microscopic level, the cell's
cytoskeleton of chiral filaments seems always to be involved, usually in
collective states driven by polymerization forces or molecular motors. It seems
particularly easy for handedness to emerge in a shear or rotation in the
background of an effectively two-dimensional system, such as the cell membrane
or a layer of cells, as this requires no pre-existing axis apart from the layer
normal. I detail a scenario involving actin/myosin layers in snails and in C.
elegans, and also one about the microtubule layer in plant cells. I also survey
the other examples that I am aware of, such as the emergence of handedness such
as the emergence of handedness in neurons, in eukaryote cell motility, and in
non-flagellated bacteria.Comment: 42 pages, 6 figures, resubmitted to J. Stat. Phys. special issue.
Major rewrite, rearranged sections/subsections, new Fig 3 + 6, new physics in
Sec 2.4 and 3.4.1, added Sec 5 and subsections of Sec
Calibration of the Transport Parameters of a Local Problem of Water Quality in Igap\'o I Lake
The calibration of a model refers to the process by which one can estimate
some parameters by comparisons with observed data. Due to the dynamical nature
of the environment, variations between predicted and observed values occur.
Thus, the environmental parameters may vary due to random temperature changes,
time of discharge flow, time of the day, and other conditions. Such variations
can be minimized by identifying and optimizing some parameters of the transport
model, like the values of diffusion coefficients in x and y directions and the
kinetic parameter that describes the process of removing pollutants. This paper
presents results concerning the calibration of transport parameters for
two-dimensional problems of water quality (fecal coliform control) at Igap\'o I
Lake, located in Londrina, Paran\'a, Brazil. Thus, the
convection-diffusion-reaction equation, which describes mathematically the
process studied in this work, is resolved by a semidiscrete finite element
method (SUPG) which combines finite differences in time and finite elements in
space.Comment: 8 Pages, 3 figures, 2 tables, XVIII International Conference on Water
Resources CMWR 2010 - J. Carrera (Ed) - CIMNE, Barcelona 201
Identification of GPI anchor attachment signals by a Kohonen self-organizing map
Immunogenetics and cellular immunology of bacterial infectious disease
Determination of the number of psi ' events at BESIII
The number of psi' events accumulated by the BESIII experiment from March 3 through April 14, 2009, is determined by counting inclusive hadronic events. The result is 106.41x(1.00+/-0.81%)x10(6). The error is systematic dominant; the statistical error is negligible
Measurement of the W+W- Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Dilepton Events
We present a measurement of the W+W- production cross section using 184/pb of
ppbar collisions at a center-of-mass energy of 1.96 TeV collected with the
Collider Detector at Fermilab. Using the dilepton decay channel W+W- ->
l+l-vvbar, where the charged leptons can be either electrons or muons, we find
17 candidate events compared to an expected background of 5.0+2.2-0.8 events.
The resulting W+W- production cross section measurement of sigma(ppbar -> W+W-)
= 14.6 +5.8 -5.1 (stat) +1.8 -3.0 (syst) +-0.9 (lum) pb agrees well with the
Standard Model expectation.Comment: 8 pages, 2 figures, 2 tables. To be submitted to Physical Review
Letter
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