Spitzer observations of the neutron star (ultracompact) X-ray binary (XRB) 4U 0614+091 with the I... more Spitzer observations of the neutron star (ultracompact) X-ray binary (XRB) 4U 0614+091 with the Infrared Array Camera reveal emission of nonthermal origin in the range 3.5-8 mum. The mid-infrared spectrum is well fit by a power law with spectral index of alpha=-0.57+/-0.04 (where the flux density is Fnu~nualpha). Given the ultracompact nature of the binary system, we exclude the possibility
The black hole candidate and microquasar H1743-322 (aka IGR J17464-3213) has entered a new outbur... more The black hole candidate and microquasar H1743-322 (aka IGR J17464-3213) has entered a new outburst (ATel #3263). In addition to the Galactic Bulge Monitoring (Kuulkers et al., 2007 A&A, 466,595) observations, the source was also in the field of view of IBIS/ISGRI (20-500 keV) during the INTEGRAL observations of the inner Galactic disc. The latter were performed during the satellite
Human immunodeficiency virus type 1 (HIV-1) impairs major functions of macrophages but the molecu... more Human immunodeficiency virus type 1 (HIV-1) impairs major functions of macrophages but the molecular basis for this defect remains poorly characterized. Here, we show that macrophages infected with HIV-1 were unable to respond efficiently to phagocytic triggers and to clear bacteria. The maturation of phagosomes, defined by the presence of late endocytic markers, hydrolases, and reactive oxygen species, was perturbed in HIV-1-infected macrophages. We showed that maturation arrest occurred at the level of the EHD3/MICAL-L1 endosomal sorting machinery. Unexpectedly, we found that the regulatory viral protein (Vpr) was crucial to perturb phagosome maturation. Our data reveal that Vpr interacted with EB1, p150(Glued), and dynein heavy chain and was sufficient to critically alter the microtubule plus end localization of EB1 and p150(Glued), hence altering the centripetal movement of phagosomes and their maturation. Thus, we identify Vpr as a modulator of the microtubule-dependent endocyt...
We present femtosecond transient absorption measurements on the semiconductor conjugated polymers... more We present femtosecond transient absorption measurements on the semiconductor conjugated polymers poly(9,9-dioctylfluorene) (F8) and poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT). Detailed photophysical modeling reveals that, in F8, sequential excitation, first to ...
Time-resolved optical and infrared polarimetric observations of black hole and neutron star low-m... more Time-resolved optical and infrared polarimetric observations of black hole and neutron star low-mass X-ray binaries are presented. Data were acquired with the VLT, UKIRT and HIPPO on the SAAO 1.9-m. We find that for some sources in outburst, a rapidly variable component of polarization is evident that is stronger in the redder wavebands. We attribute this to the polarimetric signature
The neutron star X-ray binary Aql X-1 shows quasi-periodic outbursts about once a year. These act... more The neutron star X-ray binary Aql X-1 shows quasi-periodic outbursts about once a year. These active states are relatively well covered in optical/infrared and X-ray domains. In contrast, at radio wavelengths the observations are very scarce (IAUC #5112; ATEL #286; ATEL #491). Following the reports of a new outburst of the object (ATEL #1970; ATEL #1977), we observed Aql X-1
We report on a Swift follow-up observation of the X-ray transient MAXI J1659-152 (ATel #2873, ATe... more We report on a Swift follow-up observation of the X-ray transient MAXI J1659-152 (ATel #2873, ATel #2877, GCN #11296). This source is suggested to be a stellar-mass black hole candidate (Kalamkar et al. 2011, arXiv:1012.4330). The source also has a very short orbital period ~2.4 hours (Kuulkers et al. 2011, arXiv:1102.2102). The optical counterpart of MAXI J1659-152 has been identified
Aequorin, the bioluminescent protein found in the jellyfish Aequorea sp., has been immobilized in... more Aequorin, the bioluminescent protein found in the jellyfish Aequorea sp., has been immobilized in a porous sol-gel glass environment. The luminescence from this protein is specifically triggered by the presence of calcium ions, thus offering exciting possibilities for the development of an optical biosensor for this cationic species. The luminescence emission spectrum has been measured from the aequorin protein after interaction with calcium ions. The intensity of the luminescence, measured at the peak maximum of 470 nm, for the encapsulated protein has been calibrated against calcium ion concentration. The characterization of the protein within the sol-gel matrix has been reported together with biosensing experiments using human sera and milk samples. The results suggest that the sol-gel encapsulated aequorin protein offers potential as a one shot bioluminescence based biosensor for the determination of calcium ions in such complex matrices.
Following the report of the newly detected outburst of the transient XTE J1728-295 (possibly IGR ... more Following the report of the newly detected outburst of the transient XTE J1728-295 (possibly IGR J17285-2922 detected by INTEGRAL) in the RXTE PCA bulge scans (ATel #2823), we requested a Swift ToO observation to follow up the source based on the position given by the RXTE PCA best fit results (ATel #2823). The observation was performed on 2010-08-30 14:00:46 (UT)
Spitzer observations of the neutron star (ultracompact) X-ray binary (XRB) 4U 0614+091 with the I... more Spitzer observations of the neutron star (ultracompact) X-ray binary (XRB) 4U 0614+091 with the Infrared Array Camera reveal emission of nonthermal origin in the range 3.5-8 mum. The mid-infrared spectrum is well fit by a power law with spectral index of alpha=-0.57+/-0.04 (where the flux density is Fnu~nualpha). Given the ultracompact nature of the binary system, we exclude the possibility
The black hole candidate and microquasar H1743-322 (aka IGR J17464-3213) has entered a new outbur... more The black hole candidate and microquasar H1743-322 (aka IGR J17464-3213) has entered a new outburst (ATel #3263). In addition to the Galactic Bulge Monitoring (Kuulkers et al., 2007 A&A, 466,595) observations, the source was also in the field of view of IBIS/ISGRI (20-500 keV) during the INTEGRAL observations of the inner Galactic disc. The latter were performed during the satellite
Human immunodeficiency virus type 1 (HIV-1) impairs major functions of macrophages but the molecu... more Human immunodeficiency virus type 1 (HIV-1) impairs major functions of macrophages but the molecular basis for this defect remains poorly characterized. Here, we show that macrophages infected with HIV-1 were unable to respond efficiently to phagocytic triggers and to clear bacteria. The maturation of phagosomes, defined by the presence of late endocytic markers, hydrolases, and reactive oxygen species, was perturbed in HIV-1-infected macrophages. We showed that maturation arrest occurred at the level of the EHD3/MICAL-L1 endosomal sorting machinery. Unexpectedly, we found that the regulatory viral protein (Vpr) was crucial to perturb phagosome maturation. Our data reveal that Vpr interacted with EB1, p150(Glued), and dynein heavy chain and was sufficient to critically alter the microtubule plus end localization of EB1 and p150(Glued), hence altering the centripetal movement of phagosomes and their maturation. Thus, we identify Vpr as a modulator of the microtubule-dependent endocyt...
We present femtosecond transient absorption measurements on the semiconductor conjugated polymers... more We present femtosecond transient absorption measurements on the semiconductor conjugated polymers poly(9,9-dioctylfluorene) (F8) and poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT). Detailed photophysical modeling reveals that, in F8, sequential excitation, first to ...
Time-resolved optical and infrared polarimetric observations of black hole and neutron star low-m... more Time-resolved optical and infrared polarimetric observations of black hole and neutron star low-mass X-ray binaries are presented. Data were acquired with the VLT, UKIRT and HIPPO on the SAAO 1.9-m. We find that for some sources in outburst, a rapidly variable component of polarization is evident that is stronger in the redder wavebands. We attribute this to the polarimetric signature
The neutron star X-ray binary Aql X-1 shows quasi-periodic outbursts about once a year. These act... more The neutron star X-ray binary Aql X-1 shows quasi-periodic outbursts about once a year. These active states are relatively well covered in optical/infrared and X-ray domains. In contrast, at radio wavelengths the observations are very scarce (IAUC #5112; ATEL #286; ATEL #491). Following the reports of a new outburst of the object (ATEL #1970; ATEL #1977), we observed Aql X-1
We report on a Swift follow-up observation of the X-ray transient MAXI J1659-152 (ATel #2873, ATe... more We report on a Swift follow-up observation of the X-ray transient MAXI J1659-152 (ATel #2873, ATel #2877, GCN #11296). This source is suggested to be a stellar-mass black hole candidate (Kalamkar et al. 2011, arXiv:1012.4330). The source also has a very short orbital period ~2.4 hours (Kuulkers et al. 2011, arXiv:1102.2102). The optical counterpart of MAXI J1659-152 has been identified
Aequorin, the bioluminescent protein found in the jellyfish Aequorea sp., has been immobilized in... more Aequorin, the bioluminescent protein found in the jellyfish Aequorea sp., has been immobilized in a porous sol-gel glass environment. The luminescence from this protein is specifically triggered by the presence of calcium ions, thus offering exciting possibilities for the development of an optical biosensor for this cationic species. The luminescence emission spectrum has been measured from the aequorin protein after interaction with calcium ions. The intensity of the luminescence, measured at the peak maximum of 470 nm, for the encapsulated protein has been calibrated against calcium ion concentration. The characterization of the protein within the sol-gel matrix has been reported together with biosensing experiments using human sera and milk samples. The results suggest that the sol-gel encapsulated aequorin protein offers potential as a one shot bioluminescence based biosensor for the determination of calcium ions in such complex matrices.
Following the report of the newly detected outburst of the transient XTE J1728-295 (possibly IGR ... more Following the report of the newly detected outburst of the transient XTE J1728-295 (possibly IGR J17285-2922 detected by INTEGRAL) in the RXTE PCA bulge scans (ATel #2823), we requested a Swift ToO observation to follow up the source based on the position given by the RXTE PCA best fit results (ATel #2823). The observation was performed on 2010-08-30 14:00:46 (UT)
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Papers by David Russell