Multi-filter spectrophotometry of quasar environments

A many-filter photometric technique for determining redshifts and morphological types, by fitting spectral templates to spectral energy distributions, has good potential for application in surveys. Despite success in studies performed on simulated data, the results have not been fully reliable when applied to real, low signal-to-noise data. We are investigating techniques to improve the fitting process

Revivification of confinement resonances in the photoionization of AA@C60_{60} endohedral atoms far above thresholds

It is discovered theoretically that significant confinement resonances in an $nl$ photoionization of a \textit{multielectron} atom $A$ encaged in carbon fullerenes, A@C$_{60}$, may re-appear and be strong at photon energies far exceeding the $nl$ ionization threshold, as a general phenomenon. The reasons for this phenomenon are unraveled. The Ne $2p$ photoionization of the endohedral anion Ne@C$_{60}^{5-}$ in the photon energy region of about a thousand eV above the $2p$ threshold is chosen as case study.Comment: 3 pages, 1 figure, Revtex

Integrated stress response is critical for gemcitabine resistance in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with marked chemoresistance and a 5-year survival rate of 7%. The integrated stress response (ISR) is a cytoprotective pathway initiated in response to exposure to various environmental stimuli. We used pancreatic cancer cells (PCCs) that are highly resistant to gemcitabine (Gem) and an orthotopic mouse model to investigate the role of the ISR in Gem chemoresistance. Gem induced eIF2 phosphorylation and downstream transcription factors ATF4 and CHOP in PCCs, and these effects occurred in an eIF2α-S51 phosphorylation-dependent manner as determined using PANC-1 cells, and wild type and S51 mutant mouse embryo fibroblasts. Blocking the ISR pathway in PCCs with the ISR inhibitor ISRIB or siRNA-mediated depletion of ATF4 resulted in enhanced Gem-mediated apoptosis. Polyribosomal profiling revealed that Gem caused repression of global translation and this effect was reversed by ISRIB or by expressing GADD34 to facilitate eIF2 dephosphorylation. Moreover, Gem promoted preferential mRNA translation as determined in a TK-ATF4 5'UTR-Luciferase reporter assay, and this effect was also reversed by ISRIB. RNA-seq analysis revealed that Gem upregulated eIF2 and Nrf2 pathways, and that ISRIB significantly inhibited these pathways. Gem also induced the expression of the antiapoptotic factors Nupr1, BEX2, and Bcl2a1, whereas ISRIB reduced their expression. In an orthotopic tumor model using PANC-1 cells, ISRIB facilitated Gem-mediated increases in PARP cleavage, which occurred in conjunction with decreased tumor size. These findings indicate that Gem chemoresistance is enhanced by activating multiple ISR-dependent pathways, including eIF2, Nrf2, Nupr1, BEX2, and Bcl2A1. It is suggested that targeting the ISR pathway may be an efficient mechanism for enhancing therapeutic responsiveness to Gem in PDAC

Discrimination as a frame-of-reference effect in overlapping friendship communities of ethnically diverse youth

Objectives: To what extent is the frame of reference of overlapping friendship communities important for young people’s feelings of discrimination and subjective wellbeing? That is, do youth feel better or worse to the extent that they feel less or more discrimination than their friends? Methods: Participants (N=898; Mage=14.13; SDage=3.37; 46% females; 46% Whites; 20% Indigenous; 34% other minorities) were high school students of three ethnically diverse, low SES public schools in New South Wales, Australia. Cross-sectional data were collected to measure felt discrimination, mental health, subjective wellbeing, social support and nominations of close friends. A state-of-the-art method of clustering links was used to identify overlapping friendship communities, and multiple membership multilevel models were run to examine whether community level discrimination moderated the link between individual level discrimination and wellbeing. Results: When the community level discrimination was low, there was no wellbeing related cost or benefit of individual level discrimination. But when the community level discrimination was high, individuals in those communities who themselves felt low discrimination had better wellbeing than individuals who themselves felt high discrimination. Conclusions: We provide evidence for a frame-ofreference effect involving discrimination. Individuals’ relative standing in their friendship communities with high group-level discrimination reliably predicted the individuals’ wellbeing levels, regardless of ethnicity. The results highlight the importance of identifying overlapping friendship communities for understanding the dynamics of discrimination and wellbeing of ethnically diverse youth

Branching of the Falkner-Skan solutions for λ < 0

The Falkner-Skan equation f'" + ff" + λ(1 - f'^2) = 0, f(0) = f'(0) = 0, is discussed for λ < 0. Two types of problems, one with f'(∞) = 1 and another with f'(∞) = -1, are considered. For λ = 0- a close relation between these two types is found. For λ < -1 both types of problem allow multiple solutions which may be distinguished by an integer N denoting the number of zeros of f' - 1. The numerical results indicate that the solution branches with f'(∞) = 1 and those with f'(∞) = -1 tend towards a common limit curve as N increases indefinitely. Finally a periodic solution, existing for λ < -1, is presented.

Evolution of trace gases and particles emitted by a chaparral fire in California

Biomass burning (BB) is a major global source of trace gases and particles. Accurately representing the production and evolution of these emissions is an important goal for atmospheric chemical transport models. We measured a suite of gases and aerosols emitted from an 81 hectare prescribed fire in chaparral fuels on the central coast of California, US on 17 November 2009. We also measured physical and chemical changes that occurred in the isolated downwind plume in the first ~4 h after emission. The measurements were carried out onboard a Twin Otter aircraft outfitted with an airborne Fourier transform infrared spectrometer (AFTIR), aerosol mass spectrometer (AMS), single particle soot photometer (SP2), nephelometer, LiCor CO_2 analyzer, a chemiluminescence ozone instrument, and a wing-mounted meteorological probe. Our measurements included: CO_2; CO; NO_x; NH_3; non-methane organic compounds; organic aerosol (OA); inorganic aerosol (nitrate, ammonium, sulfate, and chloride); aerosol light scattering; refractory black carbon (rBC); and ambient temperature, relative humidity, barometric pressure, and three-dimensional wind velocity. The molar ratio of excess O_3 to excess CO in the plume (ΔO_3/ΔCO) increased from −5.13 (±1.13) × 10^(−3) to 10.2 (±2.16) × 10^(−2) in ~4.5 h following smoke emission. Excess acetic and formic acid (normalized to excess CO) increased by factors of 1.73 ± 0.43 and 7.34 ± 3.03 (respectively) over the same time since emission. Based on the rapid decay of C_2H_4 we infer an in-plume average OH concentration of 5.27 (±0.97) × 10^6 molec cm^(−3), consistent with previous studies showing elevated OH concentrations in biomass burning plumes. Ammonium, nitrate, and sulfate all increased over the course of 4 h. The observed ammonium increase was a factor of 3.90 ± 2.93 in about 4 h, but accounted for just ~36% of the gaseous ammonia lost on a molar basis. Some of the gas phase NH_3 loss may have been due to condensation on, or formation of, particles below the AMS detection range. NO_x was converted to PAN and particle nitrate with PAN production being about two times greater than production of observable nitrate in the first ~4 h following emission. The excess aerosol light scattering in the plume (normalized to excess CO_2) increased by a factor of 2.50 ± 0.74 over 4 h. The increase in light scattering was similar to that observed in an earlier study of a biomass burning plume in Mexico where significant secondary formation of OA closely tracked the increase in scattering. In the California plume, however, ΔOA/ΔCO_2 decreased sharply for the first hour and then increased slowly with a net decrease of ~20% over 4 h. The fraction of thickly coated rBC particles increased up to ~85% over the 4 h aging period. Decreasing OA accompanied by increased scattering/particle coating in initial aging may be due to a combination of particle coagulation and evaporation processes. Recondensation of species initially evaporated from the particles may have contributed to the subsequent slow rise in OA. We compare our results to observations from other plume aging studies and suggest that differences in environmental factors such as smoke concentration, oxidant concentration, actinic flux, and RH contribute significantly to the variation in plume evolution observations

Single administration of intracameral bimatoprost implant 10 µg in patients with open-angle glaucoma or ocular hypertension

INTRODUCTION: This study evaluated the intraocular pressure (IOP)-lowering efficacy and safety of a single intracameral administration of bimatoprost implant 10 µg in adults with open-angle glaucoma or ocular hypertension. METHODS: Two identically designed, randomized, 20-month, parallel-group, phase 3 clinical trials (one study eye/patient) compared three administrations of 10- or 15-µg bimatoprost implant (day 1, weeks 16 and 32) with twice-daily topical timolol maleate 0.5%. An open-label, 24-month, phase 1/2 clinical trial compared one or two implants administered in the study eye with once-daily topical bimatoprost 0.03% in the fellow eye. Separate analyses of the pooled phase 3 and phase 1/2 study datasets evaluated outcomes in the 10-µg bimatoprost implant and comparator treatment arms after a single implant administration, up to the time of implant re-administration or rescue with IOP-lowering medication. RESULTS: In the phase 3 studies, 10-µg bimatoprost implant single administration demonstrated IOP reductions (hour 0) of 4.9-7.0 mmHg through week 15 from a mean (standard deviation, SD) baseline IOP of 24.5 (2.6) mmHg (n = 374); IOP in the topical timolol BID group was reduced by 6.0-6.3 mmHg from a mean (SD) baseline IOP of 24.5 (2.6) mmHg (n = 373). In the phase 1/2 study (n = 21), median time to use of additional IOP-lowering treatment (Kaplan-Meier analysis) was 273 days (approximately 9 months), and 5 of 21 enrolled patients (23.8%) required no additional IOP-lowering treatment up to 24 months after single administration. In each study, after a single implant administration there were no reports of corneal edema, corneal endothelial cell loss, or corneal touch, and no patients had 20% or greater loss in corneal endothelial cell density. CONCLUSIONS: Bimatoprost implant single administration lowers IOP and has a favorable safety profile. Additional studies are needed to further evaluate the duration of effect and factors predicting long-term IOP lowering after a single implant administration. TRIAL REGISTRATION NUMBERS: ClinicalTrials.gov NCT02247804, NCT02250651, and NCT01157364

Material condition assessment with eddy current sensors

Eddy current sensors and sensor arrays are used for process quality and material condition assessment of conducting materials. In an embodiment, changes in spatially registered high resolution images taken before and after cold work processing reflect the quality of the process, such as intensity and coverage. These images also permit the suppression or removal of local outlier variations. Anisotropy in a material property, such as magnetic permeability or electrical conductivity, can be intentionally introduced and used to assess material condition resulting from an operation, such as a cold work or heat treatment. The anisotropy is determined by sensors that provide directional property measurements. The sensor directionality arises from constructs that use a linear conducting drive segment to impose the magnetic field in a test material. Maintaining the orientation of this drive segment, and associated sense elements, relative to a material edge provides enhanced sensitivity for crack detection at edges

Investigating the links between ozone and organic aerosol chemistry in a biomass burning plume from a prescribed fire in California chaparral

Within minutes after emission, complex photochemistry in biomass burning smoke plumes can cause large changes in the concentrations of ozone (O_3) and organic aerosol (OA). Being able to understand and simulate this rapid chemical evolution under a wide variety of conditions is a critical part of forecasting the impact of these fires on air quality, atmospheric composition, and climate. Here we use version 2.1 of the Aerosol Simulation Program (ASP) to simulate the evolution of O_3 and secondary organic aerosol (SOA) within a young biomass burning smoke plume from the Williams prescribed fire in chaparral, which was sampled over California in November 2009. We demonstrate the use of a method for simultaneously accounting for the impact of the unidentified intermediate volatility, semi-volatile, and extremely low volatility organic compounds (here collectively called "SVOCs") on the formation of OA (using the Volatility Basis Set – VBS) and O_3 (using the concept of mechanistic reactivity). We show that this method can successfully simulate the observations of O_3, OA, NO_x, ethylene (C_2H_4), and OH to within measurement uncertainty using reasonable assumptions about the average chemistry of the unidentified SVOCs. These assumptions were (1) a reaction rate constant with OH of ~ 10^(-11) cm^3 s^(−1); (2) a significant fraction (up to ~ 50 %) of the RO_2 + NO reaction resulted in fragmentation, rather than functionalization, of the parent SVOC; (3) ~ 1.1 molecules of O_3 were formed for every molecule of SVOC that reacted; (4) ~ 60 % of the OH that reacted with the unidentified non-methane organic compounds (NMOC) was regenerated as HO_2; and (5) that ~ 50 % of the NO that reacted with the SVOC peroxy radicals was lost, presumably to organic nitrate formation. Additional evidence for the fragmentation pathway is provided by the observed rate of formation of acetic acid (CH_3COOH), which is consistent with our assumed fragmentation rate. However, the model overestimates peroxyacetyl nitrate (PAN) formation downwind by about 50 %, suggesting the need for further refinements to the chemistry. This method could provide a way for classifying different smoke plume observations in terms of the average chemistry of their SVOCs, and could be used to study how the chemistry of these compounds (and the O_3 and OA they form) varies between plumes