Polyelectrolyte-assisted removal of metal ions with ultrafiltration

Rivas, Bernabé,L.,Pereira, Eduardo,Cid, Rocí,o,Geckeler, Kurt E. Wiley Subscription Services, Inc., A Wiley Company 2005 Journal of applied polymer science Vol.95 No.5

<P>The water-soluble polymers poly(styrene sulfonic acid-co-maleic acid) and poly(acrylic acid-co-maleic acid) were investigated with respect to their metal-ion-binding ability with ultrafiltration. The studied metal ions included Ag(I), Cu(II), Ni(II), Co(II), Ca(II), Mg(II), Pb(II), Cd(II), Zn(II), Al(III), and Cr(III) ions. The retention properties of the polyelectrolytes for the metal ions depended strongly on the ligand type. As for the carboxylate ligands, with increasing concentration and pH, the metal-binding affinity increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1091–1099, 2005</P>

Water-soluble amine and imine polymers with the ability to bind metal ions in conjunction with membrane filtration

Rivas, Bernabé,L.,Pooley, S. Amalia,Pereira, Eduardo D.,Cid, Rocí,o,Luna, Maribel,Jara, M. Antonieta,Geckeler, Kurt E. Wiley Subscription Services, Inc., A Wiley Company 2005 Journal of applied polymer science Vol.96 No.1

<P>The commercial polymers poly(ethylene imine) (PEI), poly(ethylene imine epichlorohydrin), and poly(dimethylamine-co-epichlorohydrin) were purified and fractionated by ultrafiltration. Their metal-ion-binding properties with respect to different ligand groups and the effect of the concentration on the retention properties were investigated. The amine ligands of the polymers formed the most stable complexes with the metal ions. In general, there was an effect of the pH and polymer fraction size on the retention properties. As the pH and polymer fraction size increased, the affinity to bind metal ions also increased. PEI had the highest metal-retention values, particularly at higher pHs, at which the amine groups were nonprotonated and could coordinate easily with the metal ions. Only Pb(II) was poorly retained. The affinity for all the metal ions, except Pb(II), increased significantly at pH 5. The metal-ion retention decreased quickly as the filtration factor increased, except for Cu(II), Co(II), Ni(II), Cd(II), and Zn(II) ions, which were retained by over 40% at a filtration factor of 4. For other metal ions such as Pb(II), Ca(II), and Mg(II), only 10% remained bound to the polymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 222–231, 2005</P>

Poly(l-lysine) as a polychelatogen to remove toxic metals using ultrafiltration and bactericide properties of poly(l-lysine)–Cu2+ complexes

Rivas, Bernabé,L.,Maureira, Antonio,Guzmá,n, Catherine,Contreras, David,Kaim, Wolfgang,Geckeler, Kurt E. Springer-Verlag 2011 Polymer bulletin Vol.67 No.5

Novel water-soluble acryloylmorpholine copolymers: Synthesis, characterization, and metal ion binding properties

Rivas, Bernabé,L.,Maureira, Antonio,Geckeler, Kurt E. Wiley Subscription Services, Inc., A Wiley Company 2006 Journal of applied polymer science Vol.101 No.1

<P>Poly(4-acryloylmorpholine), poly(4-acryloylmorpholine-co-2-acrylamido-2-methyl-1-propane sulfonic acid), and poly(2-acrylamido-2-methyl-1-propane sulfonic acid) were synthesized by radical polymerization. The water-soluble polymers obtained, containing tertiary amino, amide, and sulfonic acid groups, were investigated, in view of their metal binding properties, as polychelatogens by using the liquid-phase polymer-based retention technique, under different experimental conditions. The metal ions investigated were Ag(I), Cu(II), Co(II), Ni(II), Cd(II), Pb(II), Zn(II), Cr(III), and Al(III). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 180–185, 2006</P>

Water-soluble polymer materials as complexing reagents for the separation of metal ions using membrane filtration

Rivas, Bernabé,L.,Pooley, S. Amalia,Pereira, Eduardo,Montoya, Erika,Cid, Rocí,o,Geckeler, Kurt E. John Wiley Sons, Ltd. 2006 Polymers for advanced technologies Vol.17 No.11

<P>The commercial, water-soluble poly(sodium anetole sulfonate) (PAnS), poly(sodium vinylsulfonate) (PVS), and poly(sodium 4-styrene sulfonate) (PStyS) were investigated as metal ion binding reagents using the liquid-phase-polymer-based retention (LPR) technique. The retention profiles of the following metal ions: Co(II), Ni(II), Ca(II), Mg(II), Pb(II), Cd(II), Zn(II), Cr(III), and Cu(II) were obtained by the LPR technique at pH 3, 5, and 7, and by changing the filtration factor Z from 0 to 10. As the pH increased, the affinity towards the metal ions increased slightly. By increasing the filtration factor Z, the affinity for the metal ions did not decrease significantly. This means that the ligand–metal interaction was strong, and it is not possible to break it by washing with water at the same pH of the filtration cell. Copyright © 2006 John Wiley & Sons, Ltd.</P>

Effects of Steroid Hormone in Avian Follicles

Caicedo Rivas, R.E.,Nieto, M. Paz-Calderon,Kamiyoshi, M. Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.4

The aim of the present study was to examine the effects of testosterone (T) and estradiol-$17{\beta}$ ($E_2$) on the production of progesterone ($P_4$) by granulosa cells, and of the $E_2$ on the production of $P_4$ and T by theca internal cells. In the first experiment, granulosa cells isolated from the largest ($F_1$) and third largest ($F_3$) preovulatory follicle were incubated for 4 h in short-term culture system, $P_4$ production by granulosa cells of both $F_1$ and $F_3$ was increased in a dose-dependent manner by ovine luteinizing hormone (oLH), but not T or $E_2$. In the second experiment, $F_1$ and $F_3$ granulosa cells cultured for 48 h in the developed monolayer culture system were recultured for an additional 48 h with increasing doses of various physiological active substances existing in the ovary, including T and $E_2$. Basal $P_4$ production for 48 h during 48 to 96 h of the cultured was about nine fold greater by $F_1$ granulosa cells than by $F_3$ granulosa cells. In substances examined oLH, chicken vasoactive intestinal polypeptide (cVIP) and T, but not $E_2$, stimulated in a dose-dependent manner $P_4$ production in both $F_1$ and $F_3$ granulosa cells. In addition, when the time course of $P_4$ production by $F_1$ granulosa cells in response to oLH, cVIP, T and $E_2$ was examined for 48 h during 48 to 96 h of culture, although $E_2$ had no effect on $P_4$ production by granulosa cells of $F_1$ during the period from 48 to 96 h of culture, $P_4$ production with oLH was found to be increased at 4 h of the culture, with a maximal 9.14 fold level at 6 h. By contrast, $P_4$ production with cVIP and T increased significantly (p<0.05) from 8 and 12 h of the culture, respectively, with maximal 6.50 fold response at 12 h and 6, 48 fold responses at 36 h. Furthermore, when $F_1$ granulosa cells were precultured with $E_2$ for various times before 4 h culture with oLH at 96 h of culture, the increase in $P_4$ production in response to oLH with a dose-related manner was only found at a pretreatment time of more than 12 h. In the third experiment, theca internal cells of $F_1$, $F_2$ and the largest third to fifth preovulatory follicles ($F_{3-5}$) were incubated for 4 h in short-term culture system with increasing doses of $E_2$. The production of $P_4$ and T by theca internal cells were increased with the addition of $E_2$ of $10^{-6}M$. These increases were greater in smaller follicles. These results indicate that, in granulosa cells of the hen, T may have a direct stimulatory action in the long term on $P_4$ production, and on $E_2$ in long-term action which may enhance the sensitivity to LH for $P_4$ production, and thus, in theca internal cells, $E_2$ in short term action may stimulate the production of $P_4$ and T.

Diverse Molecular Resistance Mechanisms of Bacillus megaterium During Metal Removal Present in a Spent Catalyst

Andrea Rivas-Castillo,Domancar Orona-Tamayo,Marlenne Gómez-Ramírez,Norma G. Rojas-Avelizapa 한국생물공학회 2017 Biotechnology and Bioprocess Engineering Vol.22 No.3

Bacillus megaterium strain MNSH1-9K-1, isolated from a high-metal content site in Guanajuato, Mexico, has the intrinsic capacity to remove vanadium (V) and nickel (Ni) from a petrochemical spent catalyst, and counteract the toxic effects produced in the cell due to the presence of oxidative stress. Since knowledge of the molecular components involved in the microbial resistance to spent catalysts is scarce, this study aimed to identify the proteins potentially involved in the enhanced resistance of a B. megaterium strain, during the removal of metals contained in a spent catalyst. Thus, the current research uses a proteomic approach to investigate and evidence the differences in the molecular resistance mechanisms of two B. megaterium strains, one isolated from a mining site and a wild type strain, when both are exposed to a spent catalyst. In addition, we studied their ability to eliminate nickel (Ni), vanadium (V), aluminum (Al) and molybdenum (Mo). The data presented here may contribute to the knowledge of the molecular mechanisms involved in the resistance of B. megaterium to high metal content wastes, as well as its potential utilization for the recovery of valuable industrial metals.

Vascular Responses to Manual PC6 Acupuncture in Nonsmokers and Smokers Assessed by the Second Derivative of the Finger Photoplethysmogram Waveform

José F. Rivas-Vilchis,Ricardo Escorcia-Gaona,Jorge A. Cervantes-Reyes,Rubén Román-Ramos 사단법인약침학회 2008 Journal of Acupuncture & Meridian Studies Vol.1 No.1

Background: Smoking is reported to increase arterial stiffness. Indices obtained from the second derivative of digital volume pulse (SDDVP) waveform have been proposed to characterize vascular aging and arterial rigidity. PC6 (Neiguan) is a traditional acupoint in each forearm that has been shown to modify cardiovascular functioning. Objective: To investigate the acute effects of manual needling with PC6 on SDDVP indices in healthy chronic smoker and nonsmoker subjects. Subjects and Methods: Aging index (AI) was defined as (b − c − d − e)/a, B:A was calculated as the ratio of the absolute value for the height of the b wave (B) to that of the a wave (A), and D:A was calculated as the ratio of the absolute value for the height of the d wave (D) to that of the a wave (A). These indices derived of the wave components of SDDVP of healthy nonsmokers (n = 40; 28.3 ± 3.0 years old) vs. chronic smokers (n = 30; 29.9 ± 2.9 years old) were compared. The digital volume pulse (DVP) was obtained by measuring infrared light transmission through the finger. Of each subject, a DVP registration 20 minutes long was obtained. PC6 was stimulated unilaterally by manual needling for 5 minutes (1−6 minutes). SDDVP indices were compared in each subject in pre- vs. post-acupuncture periods (30 seconds vs. 18 minutes, respectively). Results: At baseline, we found significant difference in B:A between nonsmokers and smokers. Comparing pre- vs. post-acupuncture periods, B:A and D:A did not show significant differences among nonsmokers, but B:A improved significantly in smokers and AI improved significantly in both nonsmokers and smokers. Conclusion: These findings suggest that manual needling with PC6 could revert some of the deleterious effects on vascular functioning produced by chronic cigarette smoking. Background: Smoking is reported to increase arterial stiffness. Indices obtained from the second derivative of digital volume pulse (SDDVP) waveform have been proposed to characterize vascular aging and arterial rigidity. PC6 (Neiguan) is a traditional acupoint in each forearm that has been shown to modify cardiovascular functioning. Objective: To investigate the acute effects of manual needling with PC6 on SDDVP indices in healthy chronic smoker and nonsmoker subjects. Subjects and Methods: Aging index (AI) was defined as (b − c − d − e)/a, B:A was calculated as the ratio of the absolute value for the height of the b wave (B) to that of the a wave (A), and D:A was calculated as the ratio of the absolute value for the height of the d wave (D) to that of the a wave (A). These indices derived of the wave components of SDDVP of healthy nonsmokers (n = 40; 28.3 ± 3.0 years old) vs. chronic smokers (n = 30; 29.9 ± 2.9 years old) were compared. The digital volume pulse (DVP) was obtained by measuring infrared light transmission through the finger. Of each subject, a DVP registration 20 minutes long was obtained. PC6 was stimulated unilaterally by manual needling for 5 minutes (1−6 minutes). SDDVP indices were compared in each subject in pre- vs. post-acupuncture periods (30 seconds vs. 18 minutes, respectively). Results: At baseline, we found significant difference in B:A between nonsmokers and smokers. Comparing pre- vs. post-acupuncture periods, B:A and D:A did not show significant differences among nonsmokers, but B:A improved significantly in smokers and AI improved significantly in both nonsmokers and smokers. Conclusion: These findings suggest that manual needling with PC6 could revert some of the deleterious effects on vascular functioning produced by chronic cigarette smoking.

Air-stable Fe@Au Nanoparticles Synthesized by the Microemulsion’s Methods

Jos´e Rivas,Yolanda Pi˜neiro Redondo,Esther Iglesias-Silva,J. M. Vilas-Vilela,L. M. Le´on,Manuel Arturo L´opez-Quintela 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.10

Magnetic particles covered by gold are very important in many biological applications. However,there are not simple methods to produce small (< 5-10 nm) nanoparticles. One of the main reasons for that is the general use of iron oxides as magnetic cores, which have a large crystalline mismatch with gold. The use of Fe would be more appropriate, but its high tendency to oxidation has largely precluded it from being used as a core. Here, we will show that using a simple “one-pot” successive reaction method in microemulsions, can avoid such problems and is able to produce very stable core-shell Fe@Au nanoparticles. With this procedure, nanoparticles of ∼ 6 nm with a Fe core of 3nm can easily be obtained. These Fe@Au nanoparticles, with a saturation magnetization of 1.13emu/g, are very stable even in air after magnetic separation from the solution, which shows the good covering of the Fe core by the Au shell. In this contribution we will report the key parameters, which have to be taken into account, to prepare such stable Fe@Au dispersions and analyze their optical and magnetic properties, as well as their possible applications as biosensors, targeted magnetic separation, etc.

Specific contact resistance of IGZO thin film transistors with metallic and transparent conductive oxides electrodes and XPS study of the contact/semiconductor interfaces

M.E. Rivas-Aguilar,N. Hernandez-Como,G. Gutierrez-Heredia,A. Sánchez-Martínez,M. Mireles Ramirez,M.A. Quevedo-López 한국물리학회 2018 Current Applied Physics Vol.18 No.7

In this work, the specific contact resistance (ρc) between amorphous indium-gallium-zinc-oxide (IGZO) semiconductor and different contact electrodes was obtained from thin film transistors (TFTs). Ti/Au (10/100 nm), aluminum doped zinc oxide (AZO, 100 nm) and indium tin oxide (ITO, 100 nm) were used as source/drain electrodes to fabricate IGZO TFTs. Chemical states of the contacts/semiconductor interfaces were examined by depth profile X-ray photoelectron spectroscopy (XPS) analysis to explain the origin of the differences on specific contact resistance. The lowest ρc achieved using Ti/Au was related to the formation of a TiOx interlayer due to oxygen atoms diffusing out from the semiconductor under layer, increasing the carrier concentration of IGZO at the interface and lowering the ρc. On the contrary, no interfacial reactions were observed between IGZO and AZO or ITO source/drain. However, IGZO resistivity increased with ITO contacts likely due to oxygen vacancies filling during ITO deposition. This fact seems to be the origin of the high contact resistance between IGZO and ITO, compared to IGZO-AZO and IGZO-Ti/Au interfaces.