26 results on '"Carolina Valdes"'
Search Results
2. Citric Acid-Functionalized CuO Nanoparticles Alter Biochemical Responses in Candyland Red Tomato (Solanum lycopersicum)
- Author
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Jesus M. Cantu, Yuqing Ye, Carolina Valdes, Keni Cota-Ruiz, Jose A. Hernandez-Viezcas, and Jorge L. Gardea-Torresdey
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Plant Science ,Agricultural and Biological Sciences (miscellaneous) ,Agronomy and Crop Science ,Food Science - Published
- 2022
3. Copper(II) and lead(II) adsorption onto zinc sulfide nanoparticles effects of light, pH, time, temperature, and interferences
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Jesus Cantu, E. Fletes, John Valle, Kenneth Flores, Mataz Alcoutlabi, Carolina Valdes, E. Kotsikorou, H. M. Morales, Jason G. Parsons, and A. Puente
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Environmental Engineering ,Aqueous solution ,Inorganic chemistry ,Nanoparticle ,chemistry.chemical_element ,Context (language use) ,Atmospheric temperature range ,Zinc sulfide ,Copper ,Ion ,chemistry.chemical_compound ,Adsorption ,chemistry ,Environmental Chemistry ,General Agricultural and Biological Sciences - Abstract
A ZnS nano-sorbent to remove copper(II) and lead(II) ions from aqueous solutions was prepared via a hydrothermal reaction and characterized by X-ray diffraction. The zinc sulfide nanoparticle size was determined to be 7.0 ± 0.22 nm. The effects of pH, light conditions, time, capacity, and interferences on the zinc sulfide ability to remove copper(II) and lead(II) ions from aqueous solutions were investigated. pH studies showed that pH 5 was the optimal value for zinc sulfide binding both copper(II) and lead(II) ions. Under ambient light, the binding of both ions occurred within the first 5 min. Binding capacities ranged from 116.2 to 243.9 mg/g for copper(II), 39.1 to 147.1 mg/g for lead(II) ions, and 36.1–79.4 mg/g for lead(II) ions in the dark over temperature range from 4 to 45 °C. The thermodynamic parameters showed that the binding process for both copper(II) and lead(II) ions was either spontaneous or close to equilibrium. Light conditions were also investigated in the context of cation interference and showed that the presence of hard cations had no effect on the binding of lead(II) ions. On the other hand, the presence of hard cations showed small decrease in the binding of copper(II) ions.
- Published
- 2021
4. Targeting Metal Impurities for the Detection and Quantification of Carbon Black Particles in Water via spICP-MS
- Author
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Kenneth Flores, Logan N. Rand, Carolina Valdes, Alexandria Castillo, Jesus M. Cantu, Jason G. Parsons, Paul Westerhoff, and Jorge L. Gardea-Torresdey
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Surface-Active Agents ,Soot ,Metals ,Drinking Water ,Environmental Chemistry ,General Chemistry ,Particle Size ,Mass Spectrometry - Abstract
Carbon black (CB) is a nanomaterial with numerous industrial applications and high potential for integration into nano-enabled water treatment devices. However, few analytical techniques are capable of measuring CB in water at environmentally relevant concentrations. Therefore, we intended to establish a quantification method for CB with lower detection limits through utilization of trace metal impurities as analytical tracers. Various metal impurities were investigated in six commercial CB materials, and the Monarch 1000 CB was chosen as a model for further testing. The La impurity was chosen as a tracer for spICP-MS analysis based on measured concentration, low detection limits, and lack of polyatomic interferences. CB stability in water and adhesion to the spICP-MS introduction system presented a challenge that was mitigated by the addition of a nonionic surfactant to the matrix. Following optimization, the limit of detection (64 μg/L) and quantification (122 μg/L) for Monarch 1000 CB demonstrated the applicability of this approach to samples expected to contain trace amounts of CB. When compared against gravimetric analysis and UV-visible absorption spectroscopy, spICP-MS quantification exhibited similar sensitivity but with the ability to detect concentrations an order of magnitude lower. Method detection and sensitivity was unaffected when dissolved La was spiked into CB samples at environmentally relevant concentrations. Additionally, a more complex synthetic matrix representative of drinking water caused no appreciable impact to CB quantification. In comparison to existing quantification techniques, this method has achieved competitive sensitivity, a wide working range for quantification, and high selectivity for tracing possible release of CB materials with known metal contents.
- Published
- 2022
5. Soil and foliar exposure of soybean (Glycine max) to Cu: Nanoparticle coating-dependent plant responses
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Chaoyi Deng, Yi Wang, Jesus M. Cantu, Carolina Valdes, Gilberto Navarro, Keni Cota-Ruiz, Jose Angel Hernandez-Viezcas, Chunqiang Li, Wade H. Elmer, Christian O. Dimkpa, Jason C. White, and Jorge L. Gardea-Torresdey
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Ions ,Soil ,Materials Science (miscellaneous) ,Public Health, Environmental and Occupational Health ,Metal Nanoparticles ,Soybeans ,Safety, Risk, Reliability and Quality ,Safety Research ,Citric Acid ,Copper - Abstract
In this study, we investigated the effects of citric acid (CA) coated copper oxide nanoparticles (CuO NPs) and their application method (foliar or soil exposure) on the growth and physiology of soybean (Glycine max). After nanomaterials exposure via foliar or soil application, Cu concentration was elevated in the roots, leaves, stem, pod, and seeds; distribution varied by plant organ and surface coating. Foliar application of CuO NPs at 300 mg/L and CuO-CA NPs at 75 mg/L increased soybean yield by 169.5% and 170.1%, respectively. In contrast, foliar and soil exposure to ionic Cu with all treatments (75 and 300 mg/L) had no impact on yield. Additionally, CuO-CA NPs at 300 mg/L significantly decreased Cu concentration in seeds by 46.7%, compared to control, and by 44.7%, compared to equivalent concentration of CuO NPs. Based on the total Cu concentration, CuO NPs appeared to be more accessible for plant uptake, compared to CuO-CA NPs, inducing a decrease in protein content by 56.3% and inhibiting plant height by 27.9% at 300 mg/kg under soil exposure. The translocation of Cu from leaf to root and from the root to leaf through the xylem was imaged by two-photon microscopy. The findings indicate that citric acid coating reduced CuO NPs toxicity in soybean, demonstrating that surface modification may change the toxic properties of NPs. This research provides direct evidence for the positive effects of CuO-CA NPs on soybean, including accumulation and in planta transfer of the particles, and provides important information when assessing the risk and the benefits of NP use in food safety and security.
- Published
- 2022
6. Manganese Nanoparticles Control Salinity-Modulated Molecular Responses in Capsicum annuum L. through Priming: A Sustainable Approach for Agriculture
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Carolina Valdes, Jose R. Peralta-Videa, Yuqing Ye, Keni Cota-Ruiz, Jose A. Hernandez-Viezcas, Jorge L. Gardea-Torresdey, Illya A. Medina-Velo, and Reagan S. Turley
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Renewable Energy, Sustainability and the Environment ,business.industry ,General Chemical Engineering ,Crop yield ,fungi ,food and beverages ,Nanoparticle ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Manganese ,Priming (agriculture) ,Pesticide ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Salinity ,chemistry ,Agronomy ,Germination ,Agriculture ,Environmental Chemistry ,0210 nano-technology ,business - Abstract
The application of nanomaterials as a method to overcome plant stress and increase crop yield is relatively new as compared to the use of fertilizers and pesticides in agricultural production. In t...
- Published
- 2020
7. List of contributors
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Oluwasegun Michael Abolade, Adewole T. Adetunji, Charles O. Adetunji, Hamaad Raza Ahmad, Ojuolape F. Akande, Christian P. Andersen, Muhammad Ashar Ayub, Jesus Cantu, Keni Cota-Ruiz, Wanqin Dai, Chaonan Dong, Paul O. Fatoba, Guido Fellet, Kenneth Flores, Jorge Gardea-Torresdey, Jie Hong, Siying Jia, Naum J. Kirwa, Daniel Lizzi, Xingmao Ma, Luca Marchiol, Marta Marmiroli, Polycarp C. Ofoegbu, Clement O. Ogunkunle, Luca Pagano, Laura Pilotto, Cyren M. Rico, Lorenzo Rossi, Wajid Umar, Muhammad Zia ur Rehman, Carolina Valdes, Dane C. Wagner, Xiaoxuan Wang, Ejaz Ahmad Waraich, Ye Yuqing, Peng Zhang, and Zhiyong Zhang
- Published
- 2022
8. Physiological and molecular responses of plants exposed to engineered nanomaterials
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Keni Cota-Ruiz, Carolina Valdes, Kenneth Flores, Ye Yuqing, Jesus Cantu, and Jorge Gardea-Torresdey
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- 2022
9. Environmental applications and recent innovations in single particle inductively coupled plasma mass spectrometry (SP-ICP-MS)
- Author
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Jesus Cantu, Jose A. Hernandez-Viezcas, Jason G. Parsons, Carolina Valdes, Jorge L. Gardea-Torresdey, Yuqing Ye, Kenneth Flores, and Reagan S. Turley
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Enzymatic digestion ,Chemistry ,010401 analytical chemistry ,Engineered nanomaterials ,Nanotechnology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Nanomaterials ,Particle ,0210 nano-technology ,Instrumentation ,Inductively coupled plasma mass spectrometry ,Spectroscopy - Abstract
The accumulation of engineered nanomaterials (ENMs) will increase as more applications are discovered for their unique properties and characteristics. Additionally, the presence of nanomaterials in...
- Published
- 2019
10. Toxicity of copper hydroxide nanoparticles, bulk copper hydroxide, and ionic copper to alfalfa plants: A spectroscopic and gene expression study
- Author
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Keni Cota-Ruiz, José A. Núñez-Gastélum, Jose R. Peralta-Videa, Jose A. Hernandez-Viezcas, Carolina Valdes, Alejandro Martínez-Martínez, Armando Varela-Ramirez, Jorge L. Gardea-Torresdey, and Marcos Delgado-Rios
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0106 biological sciences ,Health, Toxicology and Mutagenesis ,Metal Nanoparticles ,Ionic bonding ,chemistry.chemical_element ,Germination ,Zinc ,Manganese ,010501 environmental sciences ,Nitric Oxide ,Toxicology ,Plant Roots ,01 natural sciences ,Superoxide dismutase ,Hydroxides ,Metallothionein ,Pesticides ,Arsenic ,0105 earth and related environmental sciences ,biology ,Superoxide Dismutase ,Chemistry ,General Medicine ,Pollution ,Sulfur ,Copper ,Seedlings ,Seeds ,biology.protein ,Medicago sativa ,010606 plant biology & botany ,Nuclear chemistry - Abstract
Bulk Cu compounds such as Cu(OH)2 are extensively used as pesticides in agriculture. Recent investigations suggest that Cu-based nanomaterials can replace bulk materials reducing the environmental impacts of Cu. In this study, stress responses of alfalfa (Medicago sativa L.) seedlings to Cu(OH)2 nanoparticle or compounds were evaluated. Seeds were immersed in suspension/solutions of a Cu(OH)2 nanoform, bulk Cu(OH)2, CuSO4, and Cu(NO3)2 at 25 and 75 mg/L. Six days later, the germination, seedling growth, and the physiological and biochemical responses of sprouts were evaluated. All Cu treatments significantly reduced root elongation (average = 63%). The ionic compounds at 25 and 75 mg/L caused a reduction in all elements analyzed (Ca, K, Mg, P, Zn, and Mn), excepting for S, Fe and Mo. The bulk-Cu(OH)2 treatment reduced K (48%) and P (52%) at 75 mg/L, but increased Zn at 25 (18%) and 75 (21%) mg/L. The nano-Cu(OH)2 reduced K (46%) and P (48%) at 75 mg/L, and also P (37%) at 25 mg/L, compared with control. Confocal microscopy images showed that all Cu compounds, at 75 mg/L, significantly reduced nitric oxide, concurring with the reduction in root growth. Nano Cu(OH)2 at 25 mg/L upregulated the expression of the Cu/Zn superoxide dismutase gene (1.92-fold), while ionic treatments at 75 mg/L upregulated (∼10-fold) metallothionein (MT) transcripts. Results demonstrated that nano and bulk Cu(OH)2 compounds caused less physiological impairments in comparison to the ionic ones in alfalfa seedlings.
- Published
- 2018
11. Responses of Terrestrial Plants to Metallic Nanomaterial Exposure: Mechanistic Insights, Emerging Technologies, and New Research Avenues
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Jose A. Hernandez-Viezcas, Keni Cota-Ruiz, Carolina Valdes, Ye Yuqing, Jose R. Peralta-Videa, and Jorge L. Gardea-Torresdey
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Abiotic stress ,ved/biology ,Emerging technologies ,Terrestrial plant ,ved/biology.organism_classification_rank.species ,Environmental science ,Nanotechnology ,Metal nanoparticles ,Plant disease - Abstract
Metallic nanoparticles (NPs) are being extensively used in electronics, cosmetics, sporting goods, and medicine. Only recently, use of metallic nanomaterials extended to agricultural production, which could lead to their buildup in arable lands and affect soil productivity. Several investigations, with different NPs and under different exposure conditions, have been conducted to understand the effects of metallic NPs on terrestrial plants. These studies have propelled the application of NPs as agrochemicals that are able to supply nutrients, combat pests and weeds, and alleviate abiotic stress. The applications of novel, high-throughput technologies and advanced spectroscopic techniques have been of great help to understand the complex metabolic responses of plants to NP exposure. However, there is still limited information about the interactions of metallic NPs with plant molecules and soil components and their repercussions on agricultural productivity. This work discusses the benefits and disadvantages that metallic NPs might represent for crops. Additionally, the effects of the metallic NPs on plant physiology are analyzed by scrutinizing recent spectroscopic and gene expression/transcriptomic studies.
- Published
- 2021
12. Copper nanowires as nanofertilizers for alfalfa plants: Understanding nano-bio systems interactions from microbial genomics, plant molecular responses and spectroscopic studies
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Yi Wang, Carolina Valdes, Jorge L. Gardea-Torresdey, Chaoyi Deng, Keni Cota-Ruiz, Maria Duarte-Gardea, Yuqing Ye, and Jose A. Hernandez-Viezcas
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Environmental Engineering ,010504 meteorology & atmospheric sciences ,Microorganism ,Ionic bonding ,Metal Nanoparticles ,010501 environmental sciences ,01 natural sciences ,Plant Roots ,law.invention ,Magazine ,law ,Nano ,Environmental Chemistry ,Medicago sativa ,Waste Management and Disposal ,0105 earth and related environmental sciences ,biology ,Chemistry ,Nanowires ,fungi ,RuBisCO ,technology, industry, and agriculture ,food and beverages ,Genomics ,Pollution ,Potting soil ,biology.protein ,Dismutase ,Copper ,Nuclear chemistry - Abstract
The recent application of nano copper (Cu) compounds in the agrosystem has shown potential to improve the physiological performance and agronomical parameters of crops. We grew alfalfa (Medicago sativa) in potting mix amended with bulk, nano, and ionic Cu compounds at 80 and 280 mg Cu/kg; then, we evaluated plant performance at physiological and molecular levels. Plants treated with bulk/nano Cu presented better agronomical responses. The P and S content was reduced in bulk and ionic Cu-exposed plants, compared to controls (p ≤ .05). All Cu forms increased the content of Fe and Zn in roots and Fe in leaves, compared to controls (p ≤ .05). Leaf-superoxide dismutase expression was augmented ~27-fold and rubisco mRNA was unaffected in bulk/nano Cu-treated plants, compared to controls (p ≤ .05). Bulk/nano Cu incremented the relative abundance of microorganisms involved in the elemental uptake. These results indicate that nano Cu improved the physiology of alfalfa and can be considered as potential nanofertilizers.
- Published
- 2020
13. Plaguicidas organoclorados: Respuesta de la macrofauna en ranchos de Xico, Veracruz
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Carolina Valdespino, Lucrecia Arellano, Isabelle Barois, and Jaime Rendón von Osten
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agroquímicos ,escarabajos ,estercoleros ,lombrices de tierra ,pastizales ,suelo ,Agriculture (General) ,S1-972 ,Animal culture ,SF1-1100 - Abstract
Objetivo. Determinar la presencia y concentraciones de plaguicidas organoclorados en el suelo de ranchos lecheros con producción rústica y tecnificada y analizar la presencia y abundancia de taxones de la macrofauna del suelo y su relación con las concentraciones de plaguicidas organoclorados del suelo. Materiales y métodos. Se caracterizaron zonas dentro de cada rancho, de acuerdo con las actividades que los propietarios llevan a cabo en cada uno y se efectuaron determinaciones de concentración de familias de plaguicidas organoclorados (∑DDT, ∑HCH, ∑Heptacloro, ∑Endosulfan, ∑Clordano, ∑Drines) y del número de individuos de los grupos taxonómicos de la macrofauna del suelo. Resultados. Se encontró una relación negativa, aunque no significativa, entre las concentraciones medidas y el número de organismos. Se reportaron las curvas de rango abundancia de los grupos evaluados para cada rancho, analizando la importancia relativa de los taxones encontrados. En algunos ranchos, los potreros tienen cantidades de organoclorados por debajo del límite de detección de los instrumentos utilizados en el laboratorio, asegurando una producción de leche libre de estos plaguicidas. Conclusiones. Los plaguicidas organoclorados pueden permanecer largo tiempo acumulados en el suelo, por lo que es necesario usar otras formas para la solución de problemas como las plagas y plantas no consumidas por el ganado, como el pastoreo racional o el establecimiento de sistemas silvopastoriles.
- Published
- 2024
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14. Effect of Lanthanum Doping on the reactivity of unsupported CoMoS2 catalysts
- Author
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Jason G. Parsons, Kenneth Flores, C. Hernández, John Valle, Mataz Alcoutlabi, T.M. Eubanks, D.F. Gonzalez, Carolina Valdes, and Jorge Góngora López
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010405 organic chemistry ,Process Chemistry and Technology ,Solvothermal synthesis ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Flue-gas desulfurization ,chemistry ,X-ray photoelectron spectroscopy ,Lanthanum ,Reactivity (chemistry) ,Carbon ,Hydrodesulfurization ,Nuclear chemistry - Abstract
In the present study, catalytic systems based on La-doping were developed to improve the activity and performance of CoMoS2 hydrodesulfurization catalysts. Lanthanum-doped at 5, 10, or 25% of the Co content in CoMoS2 hydrodesulfurization catalysts were synthesized through a solvothermal process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses confirmed the catalysts were triphasic consisting of Co9S8, MoS2, and La2S3. The La doped catalysts showed enhanced catalytic activity compared with CoMoS2 synthesized under the same conditions. The CoMoS2 prepared under solvothermal synthesis conditions showed a catalytic activity of 6.80 mol g-1 s-1, however, the La0.05Co0.95MoS2 doping showed a catalytic activity of 6.51 mol g -1 s-1 whereas the La0.1Co0.9MoS2 and La0.25Co0.75MoS2 samples showed catalytic activities of 10.7 mol g-1 s-1. The reaction products indicated the major reaction pathway was direct desulfurization. The La0.25Co0.75MoS2 catalyst after one reaction cycle showed a lower amount of carbon, than the undoped CoMoS2 catalyst.
- Published
- 2021
15. Antioxidant and defense genetic expressions in corn at early-developmental stage are differentially modulated by copper form exposure (nano, bulk, ionic): Nutrient and physiological effects
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Jose A. Hernandez-Viezcas, Carolina Valdes, Yuqing Ye, Kenneth Flores, Keni Cota-Ruiz, and Jorge L. Gardea-Torresdey
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Antioxidant ,Health, Toxicology and Mutagenesis ,medicine.medical_treatment ,0211 other engineering and technologies ,02 engineering and technology ,010501 environmental sciences ,Plant Roots ,Zea mays ,01 natural sciences ,Polyphenol oxidase ,Antioxidants ,Ascorbate Peroxidases ,medicine ,Plant defense against herbivory ,Soil Pollutants ,Metallothionein ,Food science ,0105 earth and related environmental sciences ,Ions ,Manganese ,021110 strategic, defence & security studies ,Dose-Response Relationship, Drug ,biology ,Chemistry ,Public Health, Environmental and Occupational Health ,food and beverages ,General Medicine ,APX ,Pollution ,Seedlings ,Catalase ,Shoot ,Potassium ,biology.protein ,Oxidation-Reduction ,Copper ,Peroxidase - Abstract
In the present study, Zea mays seedlings grown under nano Cu(OH)2 (nCu), bulk Cu(OH)2 (bCu), and ionic CuSO4 (iCu) compound exposure were harvested after six days. The nutritional profile was determined to be significantly disrupted in the roots by 1000 ppm bCu treatment, resulting in a 58.7% reduction in potassium compared to the control. In the shoots, a significant decrease of manganese was observed for 10 and 1000 ppm iCu treatments with 55.7% and 64.2% reductions, respectively. The overall protein content and catalase (CAT) enzymatic activity, however, remained unaffected in either roots or shoots, while an absence of polyphenol oxidase (PPO) activity was observed for all samples. The genetic expression of defense-related genes, metallothionein (MT), CAT, ascorbate peroxidase (APX), and PPO was assessed. The genetic expression of MT was upregulated 50-fold in roots treated with 1000 ppm bCu. There were no significant differences in CAT transcripts among the various treatments, while APX was upregulated 28 and 19-fold in shoots treated with 10 ppm bCu and 10 ppm nCu, respectively. Meanwhile, APX mRNA levels were downregulated five-fold in shoots treated with 1000 ppm iCu. Thus, indicating that the role of APX in plant defense was reinforced in seedlings exposed to low concentration of particulate Cu compounds. Remarkably, no PPO expression was found in any of the treatments and controls, which suggests this enzyme is expressed only under specific external factors or seedlings have an “immature” cascade signaling activation of the PPO system. Taken together, these results show that bCu and nCu treatments at a low concentration do not compromise vital cell machinery but rather elicit the enhancement of defense responses as observed through the increase in APX expression. Furthermore, under optimal concentrations, these Cu treatments show promise in enhancing corn defense responses, which can ultimately lead to increases in future global crop yields.
- Published
- 2020
16. The effect of hybrid zinc oxide/graphene oxide (ZnO/GO) nano-catalysts on the photocatalytic degradation of simazine
- Author
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Jorge Góngora López, D. Ramirez, T.M. Eubanks, C. Hernández, Jason G. Parsons, Kenneth Flores, Mataz Alcoutlabi, and Carolina Valdes
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Environmental Engineering ,Materials science ,Light ,Health, Toxicology and Mutagenesis ,0208 environmental biotechnology ,Oxide ,Simazine ,chemistry.chemical_element ,02 engineering and technology ,Zinc ,010501 environmental sciences ,01 natural sciences ,Catalysis ,law.invention ,Reaction rate ,Chemical kinetics ,chemistry.chemical_compound ,law ,Environmental Chemistry ,0105 earth and related environmental sciences ,Photolysis ,Aqueous solution ,Graphene ,Public Health, Environmental and Occupational Health ,General Medicine ,General Chemistry ,Pollution ,020801 environmental engineering ,chemistry ,Chemical engineering ,Photocatalysis ,Graphite ,Zinc Oxide - Abstract
The photocatalytic degradation of simazine (SIM) was investigated using zinc oxide/graphene oxide (ZnO/GO) composite materials under visible light irradiation. The reaction kinetics was studied to optimize the reaction parameters for efficient degradation of SIM. Batch studies were performed to investigate the effects of initial reaction pH, the loading of the ZnO onto GO, and mass of catalyst on the removal of SIM from aqueous solution. A pH of 2 was determined to be the optimal reaction pH for the different ZnO-loaded GO catalysts. In addition, a mass of 40 mg of catalyst in the reaction was observed to be the most effective for the catalysts synthesized using 20 and 30 mmol of Zn2+ ions; whereas a mass of 10 mg was most effective for the ZnO/GO composite material synthesized using 10 mmol Zn2+ ions. The reaction was observed to follow a second-order kinetics for the degradation process. Furthermore, the synthesized ZnO/GO composite catalysts resulted in higher reaction rates than those observed for pure ZnO. The 30 mmol ZnO/GO composite expressed a rate of SIM degradation ten times greater than the rate observed for pure ZnO, and sixty-two times greater than the rate of photolysis. In addition, the catalyst cycling exhibited a constant photocatalytic activity for the ZnO/GO composite over three reaction cycles without the need of a conditioning cycle.
- Published
- 2020
17. Ultraviolet upconversion enhancement in triply doped NaYF4:Tm3+, Yb3+ particles: The role of Nd3+ or Gd3+ Co-doping
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Carolina Valdes, Yuanbing Mao, and Madhab Pokhrel
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Materials science ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,medicine.disease_cause ,Photochemistry ,01 natural sciences ,Neodymium ,Inorganic Chemistry ,medicine ,Irradiation ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Absorption (electromagnetic radiation) ,Spectroscopy ,Dopant ,business.industry ,Organic Chemistry ,Doping ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Photon upconversion ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,chemistry ,Optoelectronics ,0210 nano-technology ,business ,Luminescence ,Ultraviolet - Abstract
Upconversion (UC) particles are currently under intensive investigation, normally for their visible instead of ultraviolet (UV) light luminescence under near-infrared (NIR) irradiation. As a commonly studied host, NaYF4 in particular is known to have low phonon energy and high UC efficiency. Here, we present our work on enhancing UC luminescence in the UV region by adding a third dopant into a binary-doped NaYF4:Yb3+,Tm3+ host. More specifically, neodymium (Nd3+) or gadolinium (Gd3+) ions was co-doped into parent NaYF4:20mol%Yb3+,0.5mol%Tm3+ UC particles to enhance their UV UC luminescence. Experimental results demonstrated that these particles exhibited the highest degree of UV UC enhancements when co-doped with 0.05mol% Nd3+ or 2.0mol% Gd3+, expanding the potential of this type of materials into many possible applications by directly converting NIR irradiation into UV light. Fundamentally, the UV UC emission dependence of these triply doped NaYF4:Yb3+,Tm3+ particles with different Nd3+ and Gd3+ doping concentrations was investigated in terms of ground state absorption, excited state absorption and energy transfer UC mechanisms.
- Published
- 2016
18. Investigation into the thermodynamics and kinetics of the binding of Cu2+ and Pb2+ to TiS2 nanoparticles synthesized using a solvothermal process
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Jesus Cantu, Kenneth Flores, D.F. Gonzalez, John Valle, Victoria Padilla, Jason G. Parsons, Mataz Alcoutlabi, Carolina Valdes, and Jorge Góngora López
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inorganic chemicals ,chemistry.chemical_classification ,Aqueous solution ,Sulfide ,Chemistry ,Process Chemistry and Technology ,Solvothermal synthesis ,Kinetics ,Nanoparticle ,Sorption ,02 engineering and technology ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,01 natural sciences ,Pollution ,Article ,Adsorption ,Chemical Engineering (miscellaneous) ,Particle size ,0210 nano-technology ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Nuclear chemistry - Abstract
In the present study, titanium (IV) sulfide (TiS(2)) was synthesized and investigated for the removal of Cu(2+) and Pb(2+) ions from aqueous solutions. TiS(2) nanoparticles synthesized through a solvothermal synthesis were characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM). The average particle size for the TiS(2) material was determined to be 8.03 ± 0.98 nm from the diffraction pattern. Studies were performed to examine the effects of pH, temperature, time, and interfering ions on the binding of Cu(2+) and Pb(2+) to the TiS(2). As well isotherm studies were performed to determine the binding capacity of TiS(2) for both Cu(2+) and Pb(2+) ions. The pH profile studies showed optimal binding occurred at pH 2 for the sorption of both Cu(2+) and Pb(2+) to the TiS(2). The isotherm studies showed the adsorption capacities at temperatures of 4, 22, and 45°C for Cu(2+) were 243, 222, and 153 mg/g, respectively. An opposite trend in the adsorption was observed for Pb(2+) binding to the TiS(2). The observed binding capacities for Pb(2+) were 32, 166, and 357 mg/g, at temperatures of 4, 22, and 45°C, respectively. The thermodynamic parameters for binding showed a non-spontaneous process for the sorption of Cu(2+) whereas a spontaneous binding process was observed for the sorption of Pb(2+). Additionally, the binding of Cu(2+) on TiS(2) in the presence of interfering ions (Na(+), K(+), Mg(2+), and/or Ca(2+)) was observed to decrease at high concentrations; however, the binding of Pb(2+) was unaffected by the presence of the same cations.
- Published
- 2019
19. Removal of Cu(2+) and Ni(2+) from Aqueous Solution using SnO(2) Nanomaterial effect of: pH, Time, Temperature, interfering cations
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Karina Marquez, T.M. Eubanks, Jason G. Parsons, Abigail M. Zepeda, Erika Pena, Cesar Perez, Jesus Cantu, Daisy Gonzalez, Carolina Valdes, Kenneth Flores, and Luis Gonzalez Heredia
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021110 strategic, defence & security studies ,Aqueous solution ,Inorganic chemistry ,0211 other engineering and technologies ,chemistry.chemical_element ,Langmuir adsorption model ,02 engineering and technology ,Activation energy ,021001 nanoscience & nanotechnology ,Endothermic process ,Article ,Analytical Chemistry ,Ion ,Nickel ,symbols.namesake ,Adsorption ,chemistry ,Chemisorption ,symbols ,0210 nano-technology ,Spectroscopy - Abstract
Tin oxide, SnO(2), nanomaterial was synthesized and tested for the removal of Cu(2+) and Ni(2+) ions from aqueous solutions. Various parameters for the binding were investigated in batch studied, which included pH, time, temperature, and interferences. In addition, isotherm studied were performed to determine the maximum binding capacity for both Cu(2+) and Ni(2+) ions. The optimal binding pH determined from the effects of pH were to be at pH 5 for both the Cu(2+) and Ni(2+) ions. The isotherm studies were performed at temperatures of 4°C, 25 °C, and 45 °C for both the Cu(2+) and Ni(2+) ions and were found to follow the Langmuir isotherm model. The binding capacities for the Cu(2+) ions were 2.63 mg/g, 2.95 mg/g and 3.27 mg/g at the aforementioned temperatures, respectively. Whereas the binding capacities for Ni(2+) were 0.79 mg/g, 1.07 mg/g, and 1.46 mg/g at the respective temperatures. The determined thermodynamic parameters for the binding showed that the binding processes for the reactions were endothermic, as the ΔG was observed to decrease with decreasing temperatures. As well the ΔH was 28.73 kJ/mol for Cu(2+) (III) and 13.37 kJ/mol for Ni(2+). The ΔS was observed to be 92.65 J/mol for Cu(2+) and 54.53 J/mol for Ni(2+). The free energy of adsorption for the Cu(2+) was determined to be 13.99 kJ/mol and the activation energy for the binding of Ni(2+) was determined to be 8.09 KJ/mol. The activation energy data indicate that the reaction was occurring through chemisorption
- Published
- 2018
20. The use of Fe3O4/Carbon composite fibers as anode materials in lithium ion batteries
- Author
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Jason G. Parsons, Howard Campos, Jonathon Ayala, Carolina Valdes, and Mataz Alcoutlabi
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Materials science ,Polymers and Plastics ,Composite number ,chemistry.chemical_element ,Elastomer ,Ion ,Anode ,Shape-memory polymer ,chemistry ,Electroactive polymers ,Lithium ,Composite material ,Carbon ,General Environmental Science - Published
- 2018
21. Un sueño común. Plan de rehabilitación de la exestación de tren Pelícana. Valle del Elqui, Chile
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Catalina Leiva Argandoña, Liuba Alberti Zurita, Carlos Muñoz Parra, Natalia Jorquera, and Carolina Valdés Rojas
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architectural rehabilitation ,earthen construction ,deterioration in buildings ,communal spaces ,railway station ,Architecture ,NA1-9428 - Abstract
The former Pelícana train station is a earthen building that is located in the town of Pelícana in Valle del Elqui. Within the framework of a master's degree research and thanks to the research project Semilla Dicyt No 092090MP_ARQ of the Universidad de Santiago de Chile - Usach, it was raised to carry out a proposal for the rehabilitation of this abandoned space, revaluing it and putting it at the service of the needs of the sector. The study carried out responded to the characteristics of a projective type investigation, whose study events were: architectural deterioration and the needs of communal space. Research instruments were applied for the critical diagnosis of pathologies of the property and for the knowledge of the needs of common spaces by the local population, results analyzed with qualitative and quantitative techniques, respectively. Based on these preliminary results, the rehabilitation proposal was designed, which includes programs for sports, study, walking and meeting spaces. The investigation concludes in the development of an architectural rehabilitation plan for a building rooted in the sensitivity, history and identity of a locality, which has been consulted about its needs and interests in terms of the rehabilitation of this space, it is a plan that has highly gained feasibility, permanence and validity over time, which would guarantee the permanence of the implicit architectural values in the building.
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- 2022
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22. Stream food webs in tropical mountains rely on allochthonous carbon regardless of land use
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Alonso Ramírez, Gabriela Vázquez, Vinicio Sosa, Pavel García, Gonzalo Castillo, José García-Franco, Ma. Luisa Martínez, Klaus Mehltreter, Eduardo Pineda, M. Susana Alvarado-Barrientos, Federico Escobar, Carolina Valdespino, and Adolfo Campos
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Medicine ,Science - Published
- 2023
23. Microsatellite Primers for Two Threatened Orchids in Florida: Encyclia tampensis and Cyrtopodium punctatum (Orchidaceae)
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Samantha A. N. Ferguson, Kelsey A. Peeples, Joanna Weremijewicz, Stephen H. Lu, Vanessa S. Hilaire, Danielle T. Palow, Catherine M. Martinez, Andrew B. Reeve, Jasmin I. Almonte, Carolina Valdes, Jason L. Downing, Michael Hass, Natalie M. Leon, Nicolas Z. Petrakis, Frank D. Lopez, Edson A. Zarate, Sarah M. Marrero, Ana K. Lam, and Ebony D. Taylor
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0301 basic medicine ,Genetic diversity ,Orchidaceae ,biology ,commercially exploited plants ,Cyrtopodium punctatum ,Endangered species ,Plant Science ,Primer Note ,biology.organism_classification ,Encyclia tampensis ,microsatellites ,native Florida orchids ,03 medical and health sciences ,030104 developmental biology ,Natural population growth ,Genetic marker ,Botany ,Threatened species ,Microsatellite ,Ecology, Evolution, Behavior and Systematics - Abstract
Premise of the study: The Million Orchid Project at Fairchild Tropical Botanic Garden is an initiative to propagate native orchids for reintroduction into Miami’s urban landscapes. The aim of this study was to develop microsatellites for Encyclia tampensis and Cyrtopodium punctatum (Orchidaceae). Methods and Results: Ten microsatellites were developed for each species. For E. tampensis sampled from the natural population, allele numbers ranged from one to four, with an average observed heterozygosity (Ho) of 0.314 and average expected heterozygosity (He) of 0.281. For the individuals from cultivation, allele numbers ranged from one to six, with an average Ho of 0.35 and an average He of 0.224. For C. punctatum, allele numbers ranged from one to three, with an average Ho of 0.257 and an average He of 0.272. Conclusions: These microsatellites will be used to assess the genetic diversity of natural and cultivated populations with the intention of guiding genetic breeding under the Million Orchid Project.
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- 2016
24. 'Deserción' universitaria: entre desvinculaciones institucionales y búsqueda de sentidos de vida
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Carolina Valdés-Henao
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deserción ,diversidad ,educación ,formación ,vínculos (tesauro de ciencias sociales de la unesco) ,Social Sciences ,Social sciences (General) ,H1-99 - Abstract
Objetivo: en este artículo presento los resultados de una investigación que tiene como objetivo comprender los vínculos entre la educación preliminar y la educación superior, y su relación con la deserción/permanencia universitaria en Manizales. Metodología: investigación cualitativa, llevada a cabo a través de once grupos de discusión: cinco con estudiantes de educación superior, tres con estudiantes de educación media y tres con docentes de educación básica y media; más diez entrevistas a docentes de educación superior. Resultados y conclusiones: los proyectos de vida se sobreponen a los sentidos de vida y la homogenización a la diversidad, constituyendo no solo una desvinculación institucional sino continuas desvinculaciones psicológicas del estudiantado en la vida escolar. Considero finalmente la importancia de atender a la formación no como un dispositivo de control, sino como un vínculo conducente para continuar en la educación.Palabras Clave autora: proyecto de vida, sentido de vida.
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- 2018
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25. Use of Predictive Analytics to Identify Unhealthy Opioid Use and Guide Intervention.
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Valdes EG, Reist C, Aamar R, Hallisey B, Stanton ES, Williams L, Andel R, and Gorman J
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- United States, Humans, Practice Patterns, Physicians', Prescriptions, Benzodiazepines therapeutic use, Analgesics, Opioid adverse effects, Opioid-Related Disorders drug therapy
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Objective: The authors aimed to use the newly developed Opioid Risk Stratification Tool to identify individuals who may be at risk for unhealthy opioid use and to examine the impact of applying a mailing and engagement intervention to this population and their prescribers, with the goal of reducing high-risk prescribing behaviors, opioid medication use, and mortality rates., Methods: A nonrandomized controlled study was conducted with members from two Medicaid managed care organizations. In both the intervention (N=131) and control (N=187) groups, an algorithm identified members at moderate to high risk for hazardous opioid use. Members at increased risk in the intervention group and their prescribers received a letter from the managed care organization, and members still at risk 3 months after the mailing were contacted by a care coordinator. Individuals in the control group were not contacted. Medicaid claims data were used to compare opioid use and prescribing practices between groups before and after the intervention., Results: Individuals in the intervention group were less likely to have any opioid prescription postintervention compared with those in the control group (OR=0.55, p<0.001), and the intervention group had a greater reduction in the number of individuals with concurrent opioid and benzodiazepine prescriptions (OR=0.49, p=0.042). Practices such as multiple opioid prescriptions and multiple prescribers of opioids were not affected by the intervention., Conclusions: An intervention targeting individuals at risk for hazardous opioid use was associated with a reduction in some high-risk prescribing practices. Future research should determine the ideal mix of interventions to reduce as many risk factors as possible., Competing Interests: Drs. Valdes and Aamar are employed by Relias, the company that created the Opioid Risk Stratification Tool. Drs. Reist and Gorman are consultants to Relias. At the time of the study, Ms. Hallisey was employed by Partners Health Management. Dr. Gorman receives royalties from Oxford University Press. The other authors report no financial relationships with commercial interests.
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- 2023
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26. Behavioral Health Diagnoses and Health Care Use Before and During the COVID-19 Pandemic.
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Valdes EG, Gorman JM, Ren Y, Bowling M, Steiner L, Bethea J, Aamar R, Andel R, and Reist C
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- Adult, Anxiety diagnosis, Anxiety epidemiology, Child, Delivery of Health Care, Humans, Retrospective Studies, United States epidemiology, COVID-19 epidemiology, Pandemics
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Objective: Emerging evidence has suggested a population-wide worsening of psychiatric symptoms during the COVID-19 pandemic, particularly among individuals with preexisting mental health conditions. The authors investigated whether reported behavioral health problems are being identified and treated., Methods: This observational cohort study retrospectively compared Medicaid data of patients from the first year of the pandemic (2020) in the United States (N=1,589,111 patients) with the corresponding data from the year before (2019; N=1,715,872 patients). Outcome measures included several behavioral health diagnoses and health care utilization., Results: During the pandemic period examined, the numbers of patients served, adults receiving a new diagnosis of anxiety, and children receiving a new diagnosis of depression all increased. Across all age groups, nonbehavioral health emergency department visits significantly decreased., Conclusions: These findings support reports of increases in psychiatric morbidity but do not provide evidence for increased demand for health care services.
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- 2022
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