Molecular Signatures of Asphaltene Precipitation in a Depressurization Process

The effect of pressure on asphaltene aggregation is studied in a mixture of toluene–methane (90:10 wt/wt %, 61:39 mol/mol %) using coarse-grained (CG) molecular simulations to mimic a depressurization (flash liberation) process. The created CG model allows us to sample systems containing over 10000 molecules for 250 ns. At each of the pressures considered, we quantify asphaltene aggregation by computing the mass-averaged aggregation number using three metrics that differentiate among the aggregation stages proposed in the Yen–Mullins model, as well as the radius of gyration of the aggregates. The total potential energy of asphaltenes allows us to identify the pressure at which aggregation begins. The potential energy curve exhibits local maxima at high pressures and a global maximum near the bubble point pressure. A breakdown of the total potential energy of asphaltenes shows that asphaltene–solvent interactions dominate asphaltene behavior. Our identification of the asphaltene onset pressure provides molecular-level interpretation of experimental asphaltene aggregation results

Additional file 3: of Lewy body-like alpha-synuclein inclusions trigger reactive microgliosis prior to nigral degeneration

Figure S3. Antigen-presenting MHC-IIir microglia are not associated with peak of intraneuronal inclusions of pSyn in the striatum. Progression of pSyn pathology and MHC-IIir microglia in the striatum. (a) At 2 months p.i., pSyn inclusions are localized to neurites, presumably representing terminals from the SNc. (b–c) Over time pSyn inclusions become primarily localized to the soma of striatal neurons. (d) Abundant MHC-IIir microglia in the striatum primarily localized around the α-syn PFF injection site at 2 months. (e–f) MHC-IIir microglia in the striatum are largely absent during continuing accumulation of intraneuronal pSyn inclusions at 4 months (e) and 6 months (f) p.i. (g) Intrastriatal injection of PBS results abundant MHC-IIir microglia in the striatum localized near the site of injection at 2 months p.i., although appearing less abundant than MHC-IIir microglia in the striatum of α-syn PFF rats at the same time point (d). (h) MHC-IIir microglia are similarly absent from the parenchyma by 4 months (h) and 6 months p.i (i). Scale bars A–I = 50 μm. Abbreviations: p.i. = postinjection; PFFs = pre-formed alpha-synuclein fibrils; PBS = phosphate-buffered saline; pSyn = α-syn phosphorylated at serine 129, MHC-IIir = major-histocompatibility complex-II immunoreactive. (TIF 112368 kb

Additional file 1: of Lewy body-like alpha-synuclein inclusions trigger reactive microgliosis prior to nigral degeneration

Figure S1. Unilateral intrastriatal injection of α-syn PFFs, but not RSA or PBS, induces bilateral cortical and unilateral SNc Lewy-body like inclusions of phosphorylated α-syn (pSyn). (a) pSyn pathology is observed bilaterally in cortical areas after unilateral injection of α-syn PFFs, namely in layers 2/3 and orbital and agranular insular cortices. (b) Injection of PBS or (c) RSA did not induce pSyn accumulation. (d) pSyn accumulation in the ipsilateral substantia nigra pars compacta (SNc) at 2 months postinjection, with no evidence of pSyn inclusions in the contralateral SNc. Scale bars (A–D) = 50 μm. Abbreviations: α-syn = alpha-synuclein; PFFs = pre-formed alpha-synuclein fibrils; PBS = phosphate-buffered saline; RSA = rat serum albumin; pSyn = α-syn phosphorylated at serine 129. (TIF 117729 kb

Additional file 3: of Lewy body-like alpha-synuclein inclusions trigger reactive microgliosis prior to nigral degeneration

Figure S3. Antigen-presenting MHC-IIir microglia are not associated with peak of intraneuronal inclusions of pSyn in the striatum. Progression of pSyn pathology and MHC-IIir microglia in the striatum. (a) At 2 months p.i., pSyn inclusions are localized to neurites, presumably representing terminals from the SNc. (b–c) Over time pSyn inclusions become primarily localized to the soma of striatal neurons. (d) Abundant MHC-IIir microglia in the striatum primarily localized around the α-syn PFF injection site at 2 months. (e–f) MHC-IIir microglia in the striatum are largely absent during continuing accumulation of intraneuronal pSyn inclusions at 4 months (e) and 6 months (f) p.i. (g) Intrastriatal injection of PBS results abundant MHC-IIir microglia in the striatum localized near the site of injection at 2 months p.i., although appearing less abundant than MHC-IIir microglia in the striatum of α-syn PFF rats at the same time point (d). (h) MHC-IIir microglia are similarly absent from the parenchyma by 4 months (h) and 6 months p.i (i). Scale bars A–I = 50 μm. Abbreviations: p.i. = postinjection; PFFs = pre-formed alpha-synuclein fibrils; PBS = phosphate-buffered saline; pSyn = α-syn phosphorylated at serine 129, MHC-IIir = major-histocompatibility complex-II immunoreactive. (TIF 112368 kb

Additional file 2: of Lewy body-like alpha-synuclein inclusions trigger reactive microgliosis prior to nigral degeneration

Figure S2. Unilateral intrastriatal injection of α-syn PFFs induces widespread accumulation of Lewy-body like inclusions of phosphorylated α-syn (pSyn). Representative images illustrating the time course of pSyn pathology in regions innervating the striatum. (a–c) pSyn pathology in the ipsilateral agranular insular cortex localized to both the soma and neurites at 2 months p.i. (postinjection) that over time becomes primarily localized to the soma; scale bar = 50 μm, inset = 10 μm. (d–f) Ipsilateral accumulation of pSyn in the substantia nigra peaks at 2 months and becomes less abundant over time as neurons degenerate; scale bar = 200 μm, inset = 25 μm. (g–i) In contrast to other areas, pSyn in the striatum is primarily localized to neurites at 2 months and becomes more abundant and localized to the soma over time, scale bar = 50 μm, inset = 10 μm. Abbreviations: α-syn = alpha-synuclein; PFFs = pre-formed alpha-synuclein fibrils; pSyn = α-syn phosphorylated at serine 129; p.i. = postinjection. (TIF 33472 kb

The Periodic Signals of Nova V1674 Herculis (2021)

We present time-series photometry during eruption of the extremely fast nova V1674 Herculis (Nova Her 2021). The 2021 light curve showed periodic signals at 0.152921(3) d and 501.486(5) s, which we interpret as respectively the orbital and white dwarf spin-periods in the underlying binary. We also detected a sideband signal at the /difference/ frequency between these two clocks. During the first 15 days of outburst, the spin-period appears to have increased by 0.014(1)%. This increase probably arose from the sudden loss of high-angular-momentum gas ("the nova explosion") from the rotating, magnetic white dwarf. Both periodic signals appeared remarkably early in the outburst, which we attribute to the extreme speed with which the nova evolved (and became transparent to radiation from the inner binary). After that very fast initial increase of ~71 ms, the spin-period commenced a steady decrease of ~160 ms/year -- about 100x faster than usually seen in intermediate polars. This is probably due to high accretion torques from very high mass-transfer rates, which might be common when low-mass donor stars are strongly irradiated by a nova outburst.</p