Diffusion of water from a range of conservation treatment gels into paint films studied by unilateral NMR: Part I: Acrylic emulsion paint

Unilateral NMR was used to monitor the penetration of water into acrylic emulsion paint-outs on canvas during cleaning simulations with five thickened conservation treatment systems – agarose gels, methylcellulose paste, Pemulen-TR2, poly(vinyl alcohol)-borax gels, and Velvesil Plus – and water-moistened swabs. Studies were also carried out to measure the rate of water penetration from the different treatment methods into acrylic paints during continuous exposure. Unilateral NMR is shown to be an effective technique for comparing depth penetration of water during cleaning treatments; the volume of paint occupied by water can be extracted from these measurements. The results show that young paint films (1 month) are more prone to swelling than aged paint films (2–50 years), with light aged paints having the highest resistance to water penetration during treatments. Aged organic pigmented acrylic paint (Hansa yellow light) shows a higher propensity for swelling during cleaning than aged titanium dioxide white paint. Cleaning simulations using water-moistened swabs and agar gels deposit approximately equivalent amounts of water into the paint films, whilst all other gel systems tested, with the exception of Velvesil Plus, tend to allow approximately 50% more water into the paint films. None of the aqueous thickened cleaning systems tested reduced the quantity of water which entered the paint films relative to swab cleaning

Motion of a massive particle attached to a spherical interface: statistical properties of the particle path

We have studied the motion of a Brownian particle on a spherical interface under gravity, with the aim of setting up a protocol to measure the friction (f) felt by such a particle in experimental conditions. Our analysis is based on the Schmoluchowski equation for particle motion. Essentially we derive a practical criterion to find f from the average particle path. Our statements are illustrated by a few experimental and numerical examples. Numerical paths are obtained by computer simulation and experimental paths are those of micrometre-sized latex or glass particles attached to spherical giant lipid (SOPC) vesicles. From experimental values of f, we estimate the surface shear viscosity of SOPC bilayers to be in the range 3-8×10^(-6) Poise

Expression of transcription factor Coup-TF1 (NR2F1) in developing occipital cortex in humans

PURPOSES: We aimed to investigate the presence, distribution and abundance of transcription factor (TF) coup-tf1 (also known as NR2F1) in the germinative zones of human telencephalon during the fetal period. This transcription factor is of significance for the normal neuronal migration and differentiation of projection neurons in the mouse forebrain.MATERIALS AND METHODS: Brain tissue samples from spontaneously aborted human fetuses aged between 12  and 28  gestational weeks (g.w.) were fixed in paraformaldehyde and histologically investigated. Sections immunostained for coup-tf1 were scanned and its expression in different zones of the occipital lobe of developing pallium was evaluated. COUP-TF1 positive cells were counted and their percentage of all DAPI-stained nuclei was calculated in order to establish the abundance of the COUP-TF1-expressing cells among the total cell population.RESULTS: COUP-TF1 expression was prominent in all investigated zones of the developing human occipital lobe at stage 17 g.w. In all zones studied, COUP-TF1 positive cells presented a relatively high fraction (~71-95 %) of the cells counted with the highest value of 95.24% in the ventricular zone.CONCLUSIONS: The present data on the location, abundance and distribution pattern of coup-tf1-expressing cells in the human occipital lobe provide information on the possibility that this TF might participate to human to corticogenesis, similarly to the mouse.

Inter- and intra-annual bacterioplankton community patterns in a deepwater sub-Arctic region:Persistent high background abundance of putative oil degraders

Oil spills at sea are one of the most disastrous anthropogenic pollution events, with the Deepwater Horizon spill providing a testament to how profoundly the health of marine ecosystems and the livelihood of its coastal inhabitants can be severely impacted by spilled oil. The fate of oil in the environment is largely dictated by the presence and activities of natural communities of oil-degrading bacteria

Proliferating cells in the adult primate cerebellar cortex after ischemia

INTRODUCTION: Brain ischemia is a devastating neurological condition with significant medical and social impact. Here we investigated the effect of experimental ischemia of different duration on the ability of the adult macaque cerebellum to produce new cells of specific phenotypes.MATERIAL AND METHODS: We used a well-established model of global brain ischemia in young adult Japanese monkeys applying bromodeoxyuridine (BrdU) for 5 days х 100 mg/kg daily. Animals were distributed into different experimental and control groups depending on postischemic survival periods: 4, 9, 15, 23, 44 days (D) and BrdU starting day. Immunohistochemical detection of BrdU+ cells, Iba1+ microglia and GFAP+ astroglia was performed on cryosections. Statistical evaluation of newly generated cells with phenotyping for microglia and astrocytes in various cortical layers of the cerebellum were done.RESULTS and CONCLUSIONS: The numbers of BrdU+ cells in some ischemic groups were significantly higher compared to control animals. By cerebrocerebellum, there was an increasing value by D4 group compared to the control, then slightly reducing in D9 and D15 groups and increasing again by D23 and D44 groups. In the spinocerebellum, an increase was detected only in D44 group. The newly generated cells were dispersed in all cerebellar cortical layers with highest concentration in Purkinje cell layer. Our data show that ischemia stimulates cellular proliferation in the cerebellum but this effect declines with time after ischemia. We found evidence for generation of new microglia but not for astroglia. Our data may contribute to a better understanding of regeneration in the cerebellum after brain ischemia

Optically targeted search for gravitational waves emitted by core-collapse supernovae during the first and second observing runs of advanced LIGO and advanced Virgo

We present the results from a search for gravitational-wave transients associated with core-collapse supernovae observed within a source distance of approximately 20 Mpc during the first and second observing runs of Advanced LIGO and Advanced Virgo. No significant gravitational-wave candidate was detected. We report the detection efficiencies as a function of the distance for waveforms derived from multidimensional numerical simulations and phenomenological extreme emission models. The sources with neutrino-driven explosions are detectable at the distances approaching 5 kpc, and for magnetorotationally driven explosions the distances are up to 54 kpc. However, waveforms for extreme emission models are detectable up to 28 Mpc. For the first time, the gravitational-wave data enabled us to exclude part of the parameter spaces of two extreme emission models with confidence up to 83%, limited by coincident data coverage. Besides, using ad hoc harmonic signals windowed with Gaussian envelopes, we constrained the gravitational-wave energy emitted during core collapse at the levels of 4.27×10-4 M·c2 and 1.28×10-1 M·c2 for emissions at 235 and 1304 Hz, respectively. These constraints are 2 orders of magnitude more stringent than previously derived in the corresponding analysis using initial LIGO, initial Virgo, and GEO 600 data

Coherent state of a nonlinear oscillator and its revival dynamics

The coherent state of a nonlinear oscillator having a nonlinear spectrum is constructed using Gazeau Klauder formalism. The weighting distribution and the Mandel parameter are studied. Details of the revival structure arising from different time scales underlying the quadratic energy spectrum are investigated by the phase analysis of the autocorrelation function

Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO’s second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h95%0=3.47×10−25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering

Refractive indices of MBE-grown AlxGa(1−x)As ternary alloys in the transparent wavelength region

A series of AlxGa(1−x)As ternary alloys were grown by molecular beam epitaxy (MBE) at the technologically relevant composition range, x < 0.45, and characterized using spectroscopic ellipsometry to provide accurate refractive index values in the wavelength region below the bandgap. Particular attention is given to O-band and C-band telecommunication wavelengths around 1.3 µm and 1.55 µm, as well as at 825 nm. MBE gave a very high accuracy for grown layer thicknesses, and the alloys’ precise compositions and bandgap values were confirmed using high-resolution x-ray diffraction and photoluminescence, to improve the refractive index model fitting accuracy. This work is the first systematic study for MBE-grown AlxGa(1−x)As across a wide spectral range. In addition, we employed a very rigorous measurement-fitting procedure, which we present in detail

Gravitational-wave constraints on the equatorial ellipticity of millisecond pulsars

We present a search for continuous gravitational waves from five radio pulsars, comprising three recycled pulsars (PSR J0437−4715, PSR J0711−6830, and PSR J0737−3039A) and two young pulsars: the Crab pulsar (J0534+2200) and the Vela pulsar (J0835−4510). We use data from the third observing run of Advanced LIGO and Virgo combined with data from their first and second observing runs. For the first time, we are able to match (for PSR J0437−4715) or surpass (for PSR J0711−6830) the indirect limits on gravitational-wave emission from recycled pulsars inferred from their observed spin-downs, and constrain their equatorial ellipticities to be less than 10−8. For each of the five pulsars, we perform targeted searches that assume a tight coupling between the gravitational-wave and electromagnetic signal phase evolution. We also present constraints on PSR J0711−6830, the Crab pulsar, and the Vela pulsar from a search that relaxes this assumption, allowing the gravitational-wave signal to vary from the electromagnetic expectation within a narrow band of frequencies and frequency derivatives