High velocity (HV) outflows are important components of SMBH growth and evolution. The ability of... more High velocity (HV) outflows are important components of SMBH growth and evolution. The ability of SMBHs to accrete matter and light up as AGN probably requires that outflows are present to carry away angular momentum. Outflows during the luminous AGN phase might also play a critical role in ``unveiling" young dust-enshrouded AGN and in ``polluting" the intergalactic medium with metals at high redshifts. Nonetheless, AGN outflows remain poorly understood. We have begun a program to study a nearly unexplored realm of AGN outflow parameter space: HV winds with v> 10,000 km/s up to v~ 0.2c but small velocity dispersions (narrow absorption lines), such that v/(Delta) v ≫ 1. These extreme outflows have been detected so far in just a few quasars, but they might be ubiquitous if, as expected, the flows subtend a small solid angle as seen from the central engine. Narrow-line HV flows merit specific attention because they pose unique challenges for theoretical models of the wind acceleration, mass loss rates, launch radii, etc. They might also comprise a significant fraction of absorbers previously attributed to unrelated (intervening) gas or galaxies. We have compiled a list of bright quasars with candidate HV outflow lines (CIV 1550 A) in existing SDSS spectra. We now propose to observe ~30 of these candidates with the 2.1m GoldCam to i) identify/confirm some of the true outflow systems (based on line variability), ii) place a firm lower limit on the fraction of quasars with narrow-line HV outflows, iii) compile a short list of confirmed HV outflow sources for future study, and iv) use the combined SDSS and GoldCam data to measure or constrain basic outflow properties, such as the kinematics, locations, and physical conditions.
For scientific purposes the ALOS PALSAR sensor can, sporadically, provide full polarimetric SAR d... more For scientific purposes the ALOS PALSAR sensor can, sporadically, provide full polarimetric SAR data (HH, HV and VV) In this paper the deterministic supervised classifier Support Vector Machines (SVM), have been studied to determine how much the use of full polarized (HH, VV and HV, no phase information) PALSAR data information can improve, or not, the overall classification accuracy in comparison with the standard products, which, for PALSAR instrument, is the HH (like JERS-1) or the dual polarization product HH-HV. The overall performance of this type of classifier is also of interest. The study area, Tapajós National Forest at the south of Santarém City, in the Brazilian Amazon, Pará State, has being object of intensive scientific observation and a set of seven classes were used to this assessment: primary forest, secondary forest, bare soil, two types of soy beans, pasture and degraded forest. The three polarimetric channels have also been filtered before the classification process by a 5 × 5 gamma filter, but the unfiltered channels were also put to test. Results showed that HH and HV filtered channels combination provided the best classification performance with 65%, but did not realize a very good separation between Primary and Secondary Forest.
Founder analysis is a method for analysis of nonrecombining DNA sequence data, with the aim of id... more Founder analysis is a method for analysis of nonrecombining DNA sequence data, with the aim of identification and dating of migrations into new territory. The method picks out founder sequence types in potential source populations and dates lineage clusters deriving from them in the settlement zone of interest. Here, using mtDNA, we apply the approach to the colonization of Europe, to estimate the proportion of modern lineages whose ancestors arrived during each major phase of settlement. To estimate the Palaeolithic and Neolithic contributions to European mtDNA diversity more accurately than was previously achievable, we have now extended the Near Eastern, European, and northern-Caucasus databases to 1,234, 2,804, and 208 samples, respectively. Both back-migration into the source population and recurrent mutation in the source and derived populations represent major obstacles to this approach. We have developed phylogenetic criteria to take account of both these factors, and we suggest a way to account for multiple dispersals of common sequence types. We conclude that (i) there has been substantial back-migration into the Near East, (ii) the majority of extant mtDNA lineages entered Europe in several waves during the Upper Palaeolithic, (iii) there was a founder effect or bottleneck associated with the Last Glacial Maximum, 20,000 years ago, from which derives the largest fraction of surviving lineages, and (iv) the immigrant Neolithic component is likely to comprise less than one-quarter of the mtDNA pool of modern Europeans.
Purpose. Fibronectin promotes corneal epithelial cell adhesion and motility in vitro and plays an... more Purpose. Fibronectin promotes corneal epithelial cell adhesion and motility in vitro and plays an important role in corneal re-epithelialization during corneal wound healing. Multiple domains contribute to the adhesion-and motility-promoting activity of fibronectin. The aim of this study was to identify amino acid sequences that contribute to the rabbit corneal epithelial (RCE) cell adhesion-and motility-promoting activity of the 33 and 66 kD carboxy-terminal heparin-binding fragments of fibronectin.
The extracellular matrix protein fibronectin (FN) plays an important role in cell adhesion, sprea... more The extracellular matrix protein fibronectin (FN) plays an important role in cell adhesion, spreading, and motility. Several cell-adhesion promoting domains exist within fibronectin, and peptide sequences from these domains have been shown to play an important role in cell interactions with fibronectin. Recently, a peptide sequence (FN-C/H-V) from the 33/66 kD carboxy-terminal heparin-binding domains of fibronectin was shown to promote the adhesion and spreading of vascular endothelial cells in vitro. Endothelial cell spreading on this peptide was followed by cytoskeletal reorganization, focal contact formation, and, ultimately, cell migration. In the current study, a photoreactive analog of FN-C/H-V (ASD-V) was generated using a heterobifunctional photoreactive crosslinking agent, sulfosuccinimidyl 2-(pazidosalicylamido) ethyl-1,3'-dithio-propionate. ASD-V was then covalently coupled to polystyrene (PS) and polyethylene terephthalate film (PET) in order to assess the utility of ASD-V for preparing biomaterial surfaces with endothelial cell-adhesion promoting properties. The effects of pre-adsorption time and initial coating concentration on the efficiency of ASD-V coupling to PS and to PET were examined. Contact angle measurements and atomic force microscopy were used to characterize ASD-V-modified surfaces. Finally, the adhesion and spreading of vascular endothelial cells on ASD-V-modified surfaces was assessed. Our results suggest that photoreactive peptides are an effective and convenient means of modifying biomaterial surfaces to impart adhesion-promoting properties and that ASD-V, when coupled to PS and PET, promotes endothelial cell adhesion and spreading and may therefore be useful as a biomaterial surface modification in applications where re-endothelialization is desired (e.g., autologous endothelial seeding of vascular grafts, or transplantation of genetically engineered endothelial cells via polymer-coated stents.
The present paper deals with the problem of fault location; a new approach requiring one-side mea... more The present paper deals with the problem of fault location; a new approach requiring one-side measurements is proposed. The distributed line equations method was chosen to describe the overhead lines. The proposed method does not require any assumption on the fault type or on the fault resistance value. The numerical tests are conducted on single- and double-circuit lines, for various fault resistance and fault distance values, and fault type conditions, simulated under ATP-EMTP.
Efficient cell electrotransfection can be achieved using combinations of high-voltage (HV; 800 V/... more Efficient cell electrotransfection can be achieved using combinations of high-voltage (HV; 800 V/cm, 100 s) and low-voltage (LV; 80 V/cm, 100 ms) pulses. We have developed equipment allowing the generation of various HV and LV combinations with precise control of the lag between the HV and LV pulses. We injected luciferase-encoding DNA in skeletal muscle, before or after pulse delivery, and measured luciferase expression after various pulse combinations. In parallel, we determined permeabilization levels using uptake of 51 Cr-labeled EDTA. High voltage alone resulted in a high level of muscle permeabilization for 300 seconds, but very low DNA transfer. Combinations of one HV pulse followed by one or four LV pulses did not prolong the high permeabilization level, but resulted in a large increase in DNA transfer for lags up to 100 seconds in the case of one HV + one LV and up to 3000 seconds in the case of one HV + four LV. DNA expression also reached similar levels when we injected the DNA between the HV and LV pulses. We conclude that the role of the HV pulse is limited to muscle cell permeabilization and that the LV pulses have a direct effect on DNA. In vivo DNA electrotransfer is thus a multistep process that includes DNA distribution, muscle permeabilization, and DNA electrophoresis.
The effects of arginine vasotocin (AVT) were examined in isolated gar arteries (afferent branchia... more The effects of arginine vasotocin (AVT) were examined in isolated gar arteries (afferent branchial, ABA; conus arteriosus, CA; ventral aorta, VA) and veins (hepatic, HV; intestinal; ovarian). AVT (10−11–10−7M) had no effect in CA, produced contraction in ABA and VA and stimulated relaxation in veins. In precontracted HV, AVT relaxation was dose-dependent, long-lived (>30 min) and reduced total tension by 49.0 ± 10.7%. EC50s for AVT, arginine vasopressin, oxytocin, desmopressin, and isotocin in gar HV were 1.4 ± 0.3, 3.6 ± 0.2, 5.3 ± 1.7, 11.0 ± 6.5, and 19.0 ± 0.4 nM,respectively. AVT was more potent compared with isotocin. Strength of relaxation (percentage decrease in total tension) of AVT and structural analogs was similar (range = 32.5 to 55%). Endothelium removal did not alter percentage relaxation or sensitivity to AVT in HV. AVT relaxation was not inhibited by nitric oxide synthase inhibitors or propranolol or reversed by addition of methylene blue but it was significantly enhanced by indomethacin (10−5M). Arginine vasopressin-receptor antagonists (V1- or V2-type selectivity; 10−6M) were equally effective inhibitors, each blocked 99% of AVT relaxation. Forskolin (10−6M) and papaverine (10−4M) relaxed precontracted gar arteries and veins. The adenylyl cyclase inhibitors SQ 22536 and MDL 12,330A (10−5M) produced transient contraction and stable relaxation, respectively, but did not inhibit AVT-induced relaxation in HV. Atrial natriuretic peptide (3 × 10−8M) and sodium nitroprusside (10−4M) had no effect in precontracted HV. AVT acts directly on gar venous smooth muscle cells via a nonclassical AVP receptor, possibly by increasing [cAMP]. AVT is a potent vasoconstrictor in vertebrate vasculature but produces a novel relaxation in gar veins.
High velocity (HV) outflows are important components of SMBH growth and evolution. The ability of... more High velocity (HV) outflows are important components of SMBH growth and evolution. The ability of SMBHs to accrete matter and light up as AGN probably requires that outflows are present to carry away angular momentum. Outflows during the luminous AGN phase might also play a critical role in ``unveiling" young dust-enshrouded AGN and in ``polluting" the intergalactic medium with metals at high redshifts. Nonetheless, AGN outflows remain poorly understood. We have begun a program to study a nearly unexplored realm of AGN outflow parameter space: HV winds with v> 10,000 km/s up to v~ 0.2c but small velocity dispersions (narrow absorption lines), such that v/(Delta) v ≫ 1. These extreme outflows have been detected so far in just a few quasars, but they might be ubiquitous if, as expected, the flows subtend a small solid angle as seen from the central engine. Narrow-line HV flows merit specific attention because they pose unique challenges for theoretical models of the wind acceleration, mass loss rates, launch radii, etc. They might also comprise a significant fraction of absorbers previously attributed to unrelated (intervening) gas or galaxies. We have compiled a list of bright quasars with candidate HV outflow lines (CIV 1550 A) in existing SDSS spectra. We now propose to observe ~30 of these candidates with the 2.1m GoldCam to i) identify/confirm some of the true outflow systems (based on line variability), ii) place a firm lower limit on the fraction of quasars with narrow-line HV outflows, iii) compile a short list of confirmed HV outflow sources for future study, and iv) use the combined SDSS and GoldCam data to measure or constrain basic outflow properties, such as the kinematics, locations, and physical conditions.
For scientific purposes the ALOS PALSAR sensor can, sporadically, provide full polarimetric SAR d... more For scientific purposes the ALOS PALSAR sensor can, sporadically, provide full polarimetric SAR data (HH, HV and VV) In this paper the deterministic supervised classifier Support Vector Machines (SVM), have been studied to determine how much the use of full polarized (HH, VV and HV, no phase information) PALSAR data information can improve, or not, the overall classification accuracy in comparison with the standard products, which, for PALSAR instrument, is the HH (like JERS-1) or the dual polarization product HH-HV. The overall performance of this type of classifier is also of interest. The study area, Tapajós National Forest at the south of Santarém City, in the Brazilian Amazon, Pará State, has being object of intensive scientific observation and a set of seven classes were used to this assessment: primary forest, secondary forest, bare soil, two types of soy beans, pasture and degraded forest. The three polarimetric channels have also been filtered before the classification process by a 5 × 5 gamma filter, but the unfiltered channels were also put to test. Results showed that HH and HV filtered channels combination provided the best classification performance with 65%, but did not realize a very good separation between Primary and Secondary Forest.
Founder analysis is a method for analysis of nonrecombining DNA sequence data, with the aim of id... more Founder analysis is a method for analysis of nonrecombining DNA sequence data, with the aim of identification and dating of migrations into new territory. The method picks out founder sequence types in potential source populations and dates lineage clusters deriving from them in the settlement zone of interest. Here, using mtDNA, we apply the approach to the colonization of Europe, to estimate the proportion of modern lineages whose ancestors arrived during each major phase of settlement. To estimate the Palaeolithic and Neolithic contributions to European mtDNA diversity more accurately than was previously achievable, we have now extended the Near Eastern, European, and northern-Caucasus databases to 1,234, 2,804, and 208 samples, respectively. Both back-migration into the source population and recurrent mutation in the source and derived populations represent major obstacles to this approach. We have developed phylogenetic criteria to take account of both these factors, and we suggest a way to account for multiple dispersals of common sequence types. We conclude that (i) there has been substantial back-migration into the Near East, (ii) the majority of extant mtDNA lineages entered Europe in several waves during the Upper Palaeolithic, (iii) there was a founder effect or bottleneck associated with the Last Glacial Maximum, 20,000 years ago, from which derives the largest fraction of surviving lineages, and (iv) the immigrant Neolithic component is likely to comprise less than one-quarter of the mtDNA pool of modern Europeans.
Purpose. Fibronectin promotes corneal epithelial cell adhesion and motility in vitro and plays an... more Purpose. Fibronectin promotes corneal epithelial cell adhesion and motility in vitro and plays an important role in corneal re-epithelialization during corneal wound healing. Multiple domains contribute to the adhesion-and motility-promoting activity of fibronectin. The aim of this study was to identify amino acid sequences that contribute to the rabbit corneal epithelial (RCE) cell adhesion-and motility-promoting activity of the 33 and 66 kD carboxy-terminal heparin-binding fragments of fibronectin.
The extracellular matrix protein fibronectin (FN) plays an important role in cell adhesion, sprea... more The extracellular matrix protein fibronectin (FN) plays an important role in cell adhesion, spreading, and motility. Several cell-adhesion promoting domains exist within fibronectin, and peptide sequences from these domains have been shown to play an important role in cell interactions with fibronectin. Recently, a peptide sequence (FN-C/H-V) from the 33/66 kD carboxy-terminal heparin-binding domains of fibronectin was shown to promote the adhesion and spreading of vascular endothelial cells in vitro. Endothelial cell spreading on this peptide was followed by cytoskeletal reorganization, focal contact formation, and, ultimately, cell migration. In the current study, a photoreactive analog of FN-C/H-V (ASD-V) was generated using a heterobifunctional photoreactive crosslinking agent, sulfosuccinimidyl 2-(pazidosalicylamido) ethyl-1,3'-dithio-propionate. ASD-V was then covalently coupled to polystyrene (PS) and polyethylene terephthalate film (PET) in order to assess the utility of ASD-V for preparing biomaterial surfaces with endothelial cell-adhesion promoting properties. The effects of pre-adsorption time and initial coating concentration on the efficiency of ASD-V coupling to PS and to PET were examined. Contact angle measurements and atomic force microscopy were used to characterize ASD-V-modified surfaces. Finally, the adhesion and spreading of vascular endothelial cells on ASD-V-modified surfaces was assessed. Our results suggest that photoreactive peptides are an effective and convenient means of modifying biomaterial surfaces to impart adhesion-promoting properties and that ASD-V, when coupled to PS and PET, promotes endothelial cell adhesion and spreading and may therefore be useful as a biomaterial surface modification in applications where re-endothelialization is desired (e.g., autologous endothelial seeding of vascular grafts, or transplantation of genetically engineered endothelial cells via polymer-coated stents.
The present paper deals with the problem of fault location; a new approach requiring one-side mea... more The present paper deals with the problem of fault location; a new approach requiring one-side measurements is proposed. The distributed line equations method was chosen to describe the overhead lines. The proposed method does not require any assumption on the fault type or on the fault resistance value. The numerical tests are conducted on single- and double-circuit lines, for various fault resistance and fault distance values, and fault type conditions, simulated under ATP-EMTP.
Efficient cell electrotransfection can be achieved using combinations of high-voltage (HV; 800 V/... more Efficient cell electrotransfection can be achieved using combinations of high-voltage (HV; 800 V/cm, 100 s) and low-voltage (LV; 80 V/cm, 100 ms) pulses. We have developed equipment allowing the generation of various HV and LV combinations with precise control of the lag between the HV and LV pulses. We injected luciferase-encoding DNA in skeletal muscle, before or after pulse delivery, and measured luciferase expression after various pulse combinations. In parallel, we determined permeabilization levels using uptake of 51 Cr-labeled EDTA. High voltage alone resulted in a high level of muscle permeabilization for 300 seconds, but very low DNA transfer. Combinations of one HV pulse followed by one or four LV pulses did not prolong the high permeabilization level, but resulted in a large increase in DNA transfer for lags up to 100 seconds in the case of one HV + one LV and up to 3000 seconds in the case of one HV + four LV. DNA expression also reached similar levels when we injected the DNA between the HV and LV pulses. We conclude that the role of the HV pulse is limited to muscle cell permeabilization and that the LV pulses have a direct effect on DNA. In vivo DNA electrotransfer is thus a multistep process that includes DNA distribution, muscle permeabilization, and DNA electrophoresis.
The effects of arginine vasotocin (AVT) were examined in isolated gar arteries (afferent branchia... more The effects of arginine vasotocin (AVT) were examined in isolated gar arteries (afferent branchial, ABA; conus arteriosus, CA; ventral aorta, VA) and veins (hepatic, HV; intestinal; ovarian). AVT (10−11–10−7M) had no effect in CA, produced contraction in ABA and VA and stimulated relaxation in veins. In precontracted HV, AVT relaxation was dose-dependent, long-lived (>30 min) and reduced total tension by 49.0 ± 10.7%. EC50s for AVT, arginine vasopressin, oxytocin, desmopressin, and isotocin in gar HV were 1.4 ± 0.3, 3.6 ± 0.2, 5.3 ± 1.7, 11.0 ± 6.5, and 19.0 ± 0.4 nM,respectively. AVT was more potent compared with isotocin. Strength of relaxation (percentage decrease in total tension) of AVT and structural analogs was similar (range = 32.5 to 55%). Endothelium removal did not alter percentage relaxation or sensitivity to AVT in HV. AVT relaxation was not inhibited by nitric oxide synthase inhibitors or propranolol or reversed by addition of methylene blue but it was significantly enhanced by indomethacin (10−5M). Arginine vasopressin-receptor antagonists (V1- or V2-type selectivity; 10−6M) were equally effective inhibitors, each blocked 99% of AVT relaxation. Forskolin (10−6M) and papaverine (10−4M) relaxed precontracted gar arteries and veins. The adenylyl cyclase inhibitors SQ 22536 and MDL 12,330A (10−5M) produced transient contraction and stable relaxation, respectively, but did not inhibit AVT-induced relaxation in HV. Atrial natriuretic peptide (3 × 10−8M) and sodium nitroprusside (10−4M) had no effect in precontracted HV. AVT acts directly on gar venous smooth muscle cells via a nonclassical AVP receptor, possibly by increasing [cAMP]. AVT is a potent vasoconstrictor in vertebrate vasculature but produces a novel relaxation in gar veins.
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