3,825 research outputs found
Photoexcitations in polythiophene at high pressure
Journal ArticleWe report optical-absorption, photoluminescence (PL), and picosecond photoinduced absorption (PA) decay in films of poly-3-hexyl-thiophene at pressures up to 80 kbar. The spectral bands redshift nonlinearly with pressure and the PL intensity decreases markedly. Thermochromic transitions are completely inhibited at pressures as low as 14 kbar. The picosecond recovery of the PA decay at high pressure is similar to that of unpressed polythiophene, but has a power-law exponent consistent with more ordered chains at high pressure. These effects suggest changes with pressure in the chain conformation and in the electronic polarizability; no changes in the interchain transfer integral are observed
High-pressure effects on ultrafast-relaxation kinetics of excitons in polydiacetylene 4BCMU
Journal ArticleUltrafast-relaxation kinetics of the singlet excitons in polydiacetylene 4BCMU was measured at hydrostatic pressures up to 80 kbar, using the pump-probe photoinduced-absorption technique with 70-fs resolution at 2 eV and 5 ps in the spectral range 1.2-2.2 eV. The 100-fs decay component survives at high pressures, but the slow component evolves from a 1.5-ps exponential decay at atmospheric pressure to a much slower stretched-exponential decay at high pressures with a complete recovery in the ns time range. Results suggest that the fast decay component is a ID relaxation process, whereas the slow component is due to exciton recombination which requires a subsequent 3D distortion of the polymer chain
Optically detected magnetic resonance study of recombination mechanisms in polythiophene
Journal ArticleFrom detailed optically detected magnetic resonance measurements in polythiophene, we show that the g=2.003 signal is luminescence enhancing, and that the signal comes from a broad photoluminescence band peaking near 1.65 eV. This band is tentatively assigned to the radiative recombination of polarons, with lifetimes between 10-8 and 5x10-5 sec
Identifikasi Aktivitas Perekonomian Masyarakat Sekitar Pelabuhan Amurang
This study aims to determine the activities of the Amurang Port on the economy of the communities around the harbor. This research was conducted at the Amurang, Sub-district of West Amurang, South Minahasa Regency. The method used in this study is a qualitative research method. The reason for using qualitative methods for this research seeks to find answers to questions relating to the socio-economic life of the commonity who are residing around the port. The data used are primary data and secondary data. Data was collected by using observation, interview and documentation. The research found that the activities in Amurang Port can increase the income of local communities, opening up a new business thus increasing employment absortion, there are trading activities and there are social-economic activities around the harbor. Thus the presence of the Amurang Port has a positive impact for the people that are around the port Amurang form of employment absortion and increased income of communit
Modeling of the human alveolar rhabdomyosarcoma Pax3-Foxo1 chromosome translocation in mouse myoblasts using CRISPR-Cas9 nuclease
Many recurrent chromosome translocations in cancer result in the generation of fusion genes that are directly implicated in the tumorigenic process. Precise modeling of the effects of cancer fusion genes in mice has been inaccurate, as constructs of fusion genes often completely or partially lack the correct regulatory sequences. The reciprocal t(2;13)(q36.1;q14.1) in human alveolar rhabdomyosarcoma (A-RMS) creates a pathognomonic PAX3-FOXO1 fusion gene. In vivo mimicking of this translocation in mice is complicated by the fact that Pax3 and Foxo1 are in opposite orientation on their respective chromosomes, precluding formation of a functional Pax3-Foxo1 fusion via a simple translocation. To circumvent this problem, we irreversibly inverted the orientation of a 4.9 Mb syntenic fragment on chromosome 3, encompassing Foxo1, by using Cre-mediated recombination of two pairs of unrelated oppositely oriented LoxP sites situated at the borders of the syntenic region. We tested if spatial proximity of the Pax3 and Foxo1 loci in myoblasts of mice homozygous for the inversion facilitated Pax3-Foxo1 fusion gene formation upon induction of targeted CRISPR-Cas9 nuclease-induced DNA double strand breaks in Pax3 and Foxo1. Fluorescent in situ hybridization indicated that fore limb myoblasts show a higher frequency of Pax3/Foxo1 co-localization than hind limb myoblasts. Indeed, more fusion genes were generated in fore limb myoblasts via a reciprocal t(1;3), which expressed correctly spliced Pax3-Foxo1 mRNA encoding Pax3-Foxo1 fusion protein. We conclude that locus proximity facilitates chromosome translocation upon induction of DNA double strand breaks. Given that the Pax3-Foxo1 fusion gene will contain all the regulatory sequences necessary for precise regulation of its expression, we propose that CRISPR-Cas9 provides a novel means to faithfully model human diseases caused by chromosome translocation in mice.[Author Summary]: Many cancers carry recurrent chromosome translocations, which often result in the formation of fusion genes that are directly involved in the tumorigenic process. Alveolar rhabdomyosarcoma, a muscle tumor in children, is typified by a translocation that fuses the PAX3 gene on chromosome 2 to the FOXO1 gene on chromosome 13. For translocation to occur both genes need to break and the disparate ends need to fuse via a process called non-homologous end joining. We determined that physical proximity of Pax3 and Foxo1 in mouse muscle progenitor cells (myoblasts) facilitates fusion gene formation. Because Pax3 and Foxo1 in the mouse are in an opposite orientation, we used a chromosome engineering strategy to invert the orientation of Foxo1 so that upon translocation a productive Pax3-Foxo1 fusion gene is created. Co-localization of the Pax3 and Foxo1 loci is higher in fore limb than in hind limb myoblasts. Simultaneous induction of a targeted double strand DNA break in each gene by CRISPR-Cas9 nuclease generated more fusion genes in fore limb than in hind limb myoblasts. Thus, gene proximity facilitates fusion gene formation. We propose that CRISPR-Cas9 nuclease can be used for the precise modeling of chromosome translocations of human cancer in mice.This work was supported by the Van Vleet foundation of Memphis and ALSAC of St Jude Children’s Research Hospital and the Cancer Center Core Grant 5P30CA021765-34. BVB and JJC were supported by grant C1178/A4520 from Cancer Research UK.Peer Reviewe
The liquidity impact on bond calculation on credit losses : a Malaysian banks’ perspective
Purpose: The aim of this paper is to empirically determine the stance of the Nigerian financial sector in absorbing or intensifying trade shocks. Design/Methodology/Approach: Towards achieving this objective, the study uses Auto-Regressive Distributed Lag (ARDL) technique to analyse annual data from 1981 to 2017. Data used in this study were sourced from Central Bank of Nigeria Statistical Bulletin and Statista. Findings: Major finding from the long-run result shows that financial development intensifies trade-led shocks, there by yielding to output volatility. Practical implication: Based on findings, the study recommends the Nigerian government to focus on the achievement of greater and more inclusive financial development. This can be achieved through; increasing the availability and affordability of financial services, easing access to loans, improving soundness of banks and fostering legal traditions that protect creditors and investors. Originality/Value: In addition to the lack of available literature with focus on this subject in the Nigerian sphere, understanding the role of Nigerian financial sector in absorbing trade-led shocks is fundamental in optimizing Nigeria’s benefits from trade. This is of utmost importance, particularly in a time where the nation just signed the Africa Continental Free Trade Agreement.peer-reviewe
SYSTEMS-2: a randomised phase II study of radiotherapy dose escalation for pain control in malignant pleural mesothelioma
SYSTEMS-2 is a randomised study of radiotherapy dose escalation for pain control in 112 patients with malignant pleural mesothelioma (MPM). Standard palliative (20Gy/5#) or dose escalated treatment (36Gy/6#) will be delivered using advanced radiotherapy techniques and pain responses will be compared at week 5. Data will guide optimal palliative radiotherapy in MPM
Facile O-atom insertion into C-C and C-H bonds by a trinuclear copper complex designed to harness a singlet oxene
Two trinuclear copper [CuICuICuI(L)]1+ complexes have been prepared with the multidentate ligands (L) 3,3'-(1,4-diazepane-1,4-diyl)bis(1-((2-(dimethylamino)ethyl)(methyl)amino)propan-2-ol) (7-Me) and (3,3'-(1,4-diazepane-1,4-diyl)bis(1-((2-(diethylamino) ethyl)(ethyl) amino)propan-2-ol) (7-Et) as models for the active site of the particulate methane monooxygenase (pMMO). The ligands were designed to form the proper spatial and electronic geometry to harness a "singlet oxene," according to the mechanism previously suggested by our laboratory. Consistent with the design strategy, both [CuICuICuI(L)]1+ reacted with dioxygen to form a putative bis(µ3-oxo)CuIICuIICuIII species, capable of facile O-atom insertion across the central C-C bond of benzil and 2,3-butanedione at ambient temperature and pressure. These complexes also catalyze facile O-atom transfer to the C-H bond of CH3CN to form glycolonitrile. These results, together with our recent biochemical studies on pMMO, provide support for our hypothesis that the hydroxylation site of pMMO contains a trinuclear copper cluster that mediates C-H bond activation by a singlet oxene mechanism
Fate of dispersants associated with the Deepwater Horizon oil spill
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of American Chemical Society for personal use, not for redistribution. The definitive version was published in Environmental Science & Technology 45 (2011):1298–1306, doi:10.1021/es103838p.Response actions to the Deepwater Horizon oil spill included the injection of ~771,000 gallons
(2,900,000 L) of chemical dispersant into the flow of oil near the seafloor. Prior to this incident,
no deepwater applications of dispersant had been conducted and thus no data exists on the
environmental fate of dispersants in deepwater. We used ultrahigh resolution mass
spectrometry and liquid chromatography with tandem mass spectrometry (LC/MS/MS) to
identify and quantify one key ingredient of the dispersant, the anionic surfactant DOSS (dioctyl
sodium sulfosuccinate), in the Gulf of Mexico deepwater during active flow and again after
flow had ceased. Here we show that DOSS was sequestered in deepwater hydrocarbon plumes
at 1000-1200m water depth and did not intermingle with surface dispersant applications.
Further, its concentration distribution was consistent with conservative transport and dilution
at depth and it persisted up to 300 km from the well, 64 days after deepwater dispersant
applications ceased. We conclude that DOSS was selectively associated with the oil and gas
phases in the deepwater plume, yet underwent negligible, or slow, rates of biodegradation in
the affected waters. These results provide important constraints on accurate modeling of the
deepwater plume and critical geochemical contexts for future toxicological studies.The authors gratefully acknowledge funding from the National Science Foundation’s RAPID
program (OCE-1045811 to EBK, OCE-1042097 to DLV, OCE-1042650 to J. D. Kessler for R/V Cape
Hatteras cruise) and from the WHOI Director of Research. Instrumentation in the WHOI FT-MS
facility was funded by the National Science Foundation MRI program (OCE-0619608) and by
the Gordon and Betty T. Moore Foundation. Stipend support for A. Boysen was provided by the
WHOI Summer Student Fellow Program
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