4,766 research outputs found
Towards Understanding Photodegradation Pathways in Lignins:The Role of Intramolecular Hydrogen Bonding in Excited States
The photoinduced dynamics of the lignin building blocks syringol, guaiacol, and phenol were studied using time-resolved ion yield spectroscopy and velocity map ion imaging. Following irradiation of syringol and guaiacol with a broad-band femtosecond ultraviolet laser pulse, a coherent superposition of out-of-plane OH torsion and/or OMe torsion/flapping motions is created in the first excited 1ππ* (S1) state, resulting in a vibrational wavepacket, which is probed by virtue of a dramatic nonplanar → planar geometry change upon photoionization from S1 to the ground state of the cation (D0). Any similar quantum beat pattern is absent in phenol. In syringol, the nonplanar geometry in S1 is pronounced enough to reduce the degree of intramolecular H bonding (between OH and OMe groups), enabling H atom elimination from the OH group. For guaiacol, H bonding is preserved after excitation, despite the nonplanar geometry in S1, and prevents O–H bond fission. This behavior affects the propensities for forming undesired phenoxyl radical sites in these three lignin chromophores and provides important insight into their relative “photostabilities” within the larger biopolymer
Hidden Donors: The Censoring Problem in U.S. Federal Campaign Finance Data
Inferences about individual campaign contributors are limited by how the Federal Election Commission collects and reports data. Only transactions that exceed a cycle-to-date total of $200 are individually disclosed, so that contributions of many donors are unobserved. We contrast visible and "hidden" donors, i.e., small donors who are invisible due to censoring—and routinely ignored in existing research. We use the Sanders presidential campaign in 2016, whose unique campaign structure received money only through an intermediary/conduit committee. These are governed by stricter disclosure statutes, allowing us to study donors who are normally hidden. For Sanders, there were seven hidden donors for every visible donor, and altogether, hidden donors were responsible for 33.8% of Sanders' campaign funds. We show that hidden donors start giving relatively later, with contributions concentrated around early primaries. We suggest that as presidential campaign strategies change towards wooing smaller donors, more research on what motivates them is necessary
Palmoplantar keratoderma along with neuromuscular and metabolic phenotypes in Slurp1-deficient mice.
Mutations in SLURP1 cause mal de Meleda, a rare palmoplantar keratoderma (PPK). SLURP1 is a secreted protein that is expressed highly in keratinocytes but has also been identified elsewhere (e.g., spinal cord neurons). Here, we examined Slurp1-deficient mice (Slurp1(-/-)) created by replacing exon 2 with β-gal and neo cassettes. Slurp1(-/-) mice developed severe PPK characterized by increased keratinocyte proliferation, an accumulation of lipid droplets in the stratum corneum, and a water barrier defect. In addition, Slurp1(-/-) mice exhibited reduced adiposity, protection from obesity on a high-fat diet, low plasma lipid levels, and a neuromuscular abnormality (hind-limb clasping). Initially, it was unclear whether the metabolic and neuromuscular phenotypes were due to Slurp1 deficiency, because we found that the targeted Slurp1 mutation reduced the expression of several neighboring genes (e.g., Slurp2, Lypd2). We therefore created a new line of knockout mice (Slurp1X(-/-) mice) with a simple nonsense mutation in exon 2. The Slurp1X mutation did not reduce the expression of adjacent genes, but Slurp1X(-/-) mice exhibited all of the phenotypes observed in the original line of knockout mice. Thus, Slurp1 deficiency in mice elicits metabolic and neuromuscular abnormalities in addition to PPK
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Cardiovascular disease behavioral risk factors among Latinos by citizenship and documentation status.
BACKGROUND:Studies have observed that recent Latino immigrants tend to have a physical health advantage compared to immigrants who have been in the US for many years or Latinos who are born in the United States. An explanation of this phenomenon is that recent immigrants have positive health behaviors that protect them from chronic disease risk. This study aims to determine if trends in positive cardiovascular disease (CVD) risk behaviors extend to Latino immigrants in California according to citizenship and documentation status. METHODS:We examined CVD behavioral risk factors by citizenship/documentation statuses among Latinos and non-Latino US-born whites in the 2011-2015 waves of the California Health Interview Survey. Adjusted multivariable logistic regressions estimated the odds for CVD behavioral risk factors, and analyses were stratified by sex. RESULTS:In adjusted analyses, using US-born Latinos as the reference group, undocumented Latino immigrants had the lowest odds of current smoking, binge drinking, and frequency of fast food consumption. There were no differences across the groups for fruit/vegetable intake and walking for leisure. Among those with high blood pressure, undocumented immigrants were least likely to be on medication. Undocumented immigrant women had better patterns of CVD behavioral risk factors on some measures compared with other Latino citizenship and documentation groups. CONCLUSIONS:This study observes that the healthy Latino immigrant advantage seems to apply to undocumented female immigrants, but it does not necessarily extend to undocumented male immigrants who had similar behavioral risk profiles to US-born Latinos
The zebrafish xenograft platform-A novel tool for modeling KSHV-associated diseases
Kaposi\u27s sarcoma associated-herpesvirus (KSHV, also known as human herpesvirus-8) is a gammaherpesvirus that establishes life-long infection in human B lymphocytes. KSHV infection is typically asymptomatic, but immunosuppression can predispose KSHV-infected individuals to primary effusion lymphoma (PEL); a malignancy driven by aberrant proliferation of latently infected B lymphocytes, and supported by pro-inflammatory cytokines and angiogenic factors produced by cells that succumb to lytic viral replication. Here, we report the development of the firs
Aplastic Crisis as Primary Manifestation of Systemic Lupus Erythematosus
Aplastic crisis is an unusual feature of systemic lupus erythematosus (SLE). We report the case of a 54-year-old woman presenting with both (extravascular) Coombs-positive hemolytic anemia and laboratory findings of bone marrow hyporegeneration with concomitant severe neutropenia. A bone marrow biopsy confirmed aplastic crisis. Diagnostic work-up revealed soaring titers of autoantibodies (anti-nuclear, anti-double-stranded DNA, anti-cardiolipin-IgM, and anti-beta 2-glykoprotein-IgM antibodies), indicating a connective tissue disease as the most plausible reason for bone marrow insufficiency. As the criteria for SLE were fulfilled, we initiated an immunosuppressive therapy by steroids, which led to a rapid complete hematologic and clinical remission in our patient. In this case, we could report on one of the rare cases of SLE-induced aplastic crisis showing that this condition can be entirely reversed by immunosuppressive treatment and that SLE-induced aplastic crisis yields a good prognosis. In conclusion, in a case of aplastic crisis, physicians should be aware that SLE can be a rare cause that is accessible to specific treatment
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