Single and multi-component adsorptive removal of bisphenol A and 2,4-dichlorophenol from aqueous solutions with transition metal modified inorganic-organic pillared clay composites: Effect of pH and presence of humic acid.

Pillared clay based composites containing transition metals and a surfactant, namely MAlOr-NaBt (Bt=bentonite; Or=surfactant; M=Ni(2+), Cu(2+)or Co(2+)), were prepared to study selectivity and capacity toward single and multiple-component adsorption of bisphenol A (BPA) and 2,4-diclorophenol (DCP) from water. Tests were also performed to account for the presence of natural organic matter in the form of humic acid (HA). Equilibrium adsorption capacities for single components increased as follows: NaBt

Single and multi-component adsorption of salicylic acid, clofibric acid, carbamazepine and caffeine from water onto transition metal modified and partially calcined inorganic-organic pillared clay fixed beds.

Fixed-beds of transition metal (Co(2+), Ni(2+) or Cu(2+)) inorganic-organic pillared clays (IOCs) were prepared to study single- and multi-component non-equilibrium adsorption of a set of pharmaceutical and personal care products (PPCPs: salicylic acid, clofibric acid, carbamazepine and caffeine) from water. Adsorption capacities for single components revealed that the copper(II) IOCs have better affinity toward salicylic and clofibric acid. However, multi-component adsorption tests showed a considerable decrease in adsorption capacity for the acids and an unusual selectivity toward carbamazepine depending on the transition metal. This was attributed to a combination of competition between PPCPs for adsorption sites, adsorbate-adsorbate interactions, and plausible pore blocking caused by carbamazepine. The cobalt(II) IOC bed that was partially calcined to fractionate the surfactant moiety showcased the best selectivity toward caffeine, even during multi-component adsorption. This was due to a combination of a mildly hydrophobic surface and interaction between the PPCP and cobalt(II). In general, the tests suggest that these IOCs may be a potential solution for the removal of PPCPs if employed in a layered-bed configuration, to take care of families of adsorbates in a sequence that would produce sharpened concentration wavefronts.

Quantum dots of ZnSe(S) doped with copper as nanophotocatalyst in the degradation of organic dyes.

Copper-doped quantum dots of ZnSe(S) synthesized via microwave-heating conditions were used as photocatalyst in the photo-degradation of methylene blue (MB), methyl violet (MV) and victoria blue (VB) under UV irradiation (302 nm) in aqueous phase and at pH 6.5. Quantum dots were characterized by High Resolution Transmission Electron Microscopy (HR-TEM), X-ray diffraction (XRD), UV-Vis, photoluminescence and Fourier transform infrared (FT-IR) spectroscopy. The degradation of MB, MV and VB were monitored using High Performance Liquid Chromatography (HPLC) at 660 nm, 590 nm and 610 nm, respectively. Degradations percentages of 46%, 88% and 90% of MB, MV and VB, respectively, were achieved in presence of 1000 mg/L of quantum dots and 6 hours of UV-irradiation. Cu-doped ZnSe(S) QDs evidenced a remarkable capability to degrade cationic organic dyes as single components and in mixtures.

Synthesis and characterization of palladium and palladium-cobalt nanoparticles on Vulcan XC-72R for the oxygen reduction reaction.

A single-source approach was used to synthesize bimetallic nanoparticles on a high-surface-area carbon-support surface. The synthesis of palladium and palladium-cobalt nanoparticles on carbon black (Vulcan XC-72R) by chemical and thermal reduction using organometallic complexes as precursors is described. The electrocatalysts studied were Pd/C, Pd2Co/C, and PdCo2/C. The nanoparticles composition and morphology were characterized using inductively coupled plasma mass spectrophotometer (ICP-MS), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray fluorescence spectroscopy (EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. Electrocatalytic activity towards the oxygen reduction reaction (ORR) and methanol tolerance in oxygen-saturated acid solution were determined. The bimetallic catalyst on carbon support synthetized by thermal reduction of the Pd2Co precursor has ORR electrocatalytic activity and a higher methanol tolerance than a Pt/C catalyst.

Transition metal modified and partially calcined inorganic-organic pillared clays for the adsorption of salicylic acid, clofibric acid, carbamazepine, and caffeine from water.

Pharmaceutical and Personal Care Products (PPCPs) are considered emerging contaminants, and their efficient removal from water is going to be a challenging endeavor. Microporous adsorbent materials, including pillared clays, could offer a potential solution if tailored properly. Although pillared clays have been employed previously for the removal of organics, the effective removal of PPCPs will only be possible if their surface and textural properties are manipulated from the bottom-up. This work presents the use of modified inorganic-organic pillared clays (IOCs) for the adsorption of salicylic acid, clofibric acid, carbamazepine, and caffeine. The IOCs have been modified with Co(2+), Cu(2+), or Ni(2+) to induce complexation-like adsorbate-adsorbent interactions at ambient conditions, in an attempt to provide an efficient and yet reversible driving force in the sub-ppm concentration range. Furthermore, the IOCs were partially calcined to increase effective surface area by an order of magnitude while preserving some hydrophobicity. In general, the Ni(2+) IOCs exhibited the greatest interaction with salicylic and clofibric acids, respectively, while the Co(2+) adsorbents excelled at adsorbing caffeine at low concentrations. All of the metal-modified IOCs showed comparable adsorption capacities for the case of carbamazepine, probably due to the lack of availability of particular functional groups in this adsorbate.

Presencia y severidad de calcio coronario: su relación con la aparición de eventos coronarios agudos / Presence and severity of coronary calcium: its relationship with acute coronary events

Fundamento: La detección de calcio en las arterias coronarias confirma la presencia de aterosclerosis y ha demostrado ser una herramienta útil para estratificar el riesgo cardiovascular. Objetivo: determinar la relación entre la presencia y severidad de calcio coronario con la aparición de eventos coronarios agudos.Métodos: se realizó un estudio observacional, descriptivo, prospectivo, tipo serie de casos, en el Hospital Universitario Dr Gustavo Aldereguía Lima de Cienfuegos, entre enero y diciembre de 2008. La serie estuvo conformada por 137 pacientes, en los que se estudió: sexo, antecedentes patológicos personales, cifras de glucemia en ayunas, creatinina, colesterol total y triglicéridos. Los pacientes fueron seguidos durante dos años para evaluar la aparición de eventos coronarios agudos.Resultados: La edad media fue de 53,2±7,4 años, con predominio del sexo masculino (52,5 por ciento). El mayor porciento de pacientes clasificados como de alto riesgo, según la cuantificación del calcio coronario (16,8 por ciento) perteneció al sexo masculino, predominando en los mayores de 70 años. La diabetes se relacionó de forma significativa con la severidad del puntaje de calcio. El infarto agudo del miocardio fue más frecuente en pacientes con puntaje de calcio mayor de 400 unidades Agatston.Conclusiones: la aparición de eventos coronarios agudos fue más frecuente en los pacientes de alto riesgo según cuantificación del calcio coronario(AU)

Background: Calcium detection in coronary arteries confirms the presence of atherosclerosis and has proved to be a useful tool for risk stratification. Objective: To determine the relationship between the presence and severity of coronary calcium with the onset of acute coronary events. Methods: An observational, descriptive, prospective, case series study was conducted at the Dr. Gustavo Aldereguía Lima University Hospital of Cienfuegos, between January and December 2008. The series consisted of 137 patients who were studied according to: sex, personal medical history and record of fasting blood glucose, creatinine, total cholesterol and triglycerides. Patients received follow-up for two years in order to assess the occurrence of acute coronary events. Results: Average age was 53.2 ± 7.4 years, with predominance of males (52.5 percent). The greatest percentage of patients classified as high risk according to the quantification of coronary calcium (16.8 percent) were males, predominantly those over 70 years old. Diabetes was significantly associated with severity of calcium scores. Myocardial infarction was more frequent in patients with calcium scores above 400 Agatston units. Conclusions: The occurrence of acute coronary events was more frequent in patients at high risk according to coronary calcium quantification(AU)

Cuantificación del calcio coronario y riesgo cardiovascular en pacientes con diabetes mellitus tipo 2 / Coronary calcium scoring and cardiovascular risk in patients with Type 2 Diabetes Mellitus

Fundamento: la diabetes mellitus es considerada como un factor de riesgo cardiovascular independiente. Lacuantificación de calcio coronario ha demostrado ser una herramienta útil para estratificar el riesgo cardiovascular. Objetivo: cuantificar el calcio coronario en pacientes con diabetes mellitus tipo 2 para estimar elriesgo cardiovascular. Métodos: estudio descriptivo observacional que incluyó 33 pacientes con diabetes mellitus tipo 2 que ingresaron en el Centro de Atención al Diabético de Cienfuegos de abril a julio del 2009. Variables estudiadas: edad, sexo, evaluación nutricional, tiempo de evolución de la enfermedad, antecedentes dehipertensión arterial, hiperlipidemia y hábito de fumar. Se realizó la determinación del calcio coronario con un equipo de tomografía helicoidal multicorte. Resultados: predominó el sexo femenino, la mayoría de los pacientes se ubican en los grupos de 41 a 70 años, más de la mitad tenían de 2 a 11 años de evolución y presentabancifras de glucemia en ayunas mayor de 7,0 mmol/L.; el 40,0 por ciento de los diabéticos tienen tres o más factores de riesgo y valores medios y altos de calcio coronario; el 21,7 por ciento (5 pacientes) tienen menos de tres factores de riesgo y valores medios y altos. Conclusiones: la realización de una cuantificación de calcio coronario permite reclasificar en un alto porcentaje de casos el riesgo cardiovascular estimado(AU)

Background: Diabetes mellitus is considered as an independent cardiovascular risk factor. Coronary calcium scoring has proved to be a useful tool for stratifying cardiovascular risk. Objective: To quantify coronary calcium in patients with diabetes mellitus type 2 in order to estimate cardiovascular risk. Methods: A descriptive observational study was conducted. The sample included 33 patients with type 2 diabetes mellitus admitted in the Center for Diabetes Care and Education of Cienfuegos from April to July 2009. Variables studied: age, sex, nutritional assessment, illness duration, history of hypertension, hyperlipidemia and smoking. Coronary calcium was determined with multislice helical CT scanner. Results: females were predominant. Most patients were between 41 and 70 years old. More than half were from 2 to 11 years of evolution and had fasting glucose levels higher than 7.0 mmol / L. In 40.0 percent of diabetic patients three or more risk factors and average and high coronary calcium values were present. Out of the total, 21.7 percent (5 patients) has less than three risk factors and average and high values. Conclusions: Performing coronary calcium quantification can reclassify cardiovascular risk in a high percentage of estimated cases(AU)

Structure-activity studies of Ti(IV) complexes: aqueous stability and cytotoxic properties in colon cancer HT-29 cells.

As part of our research efforts in the area of titanium-based antitumor agents, we have investigated the cytotoxic activity of [Ti(4)(maltolato)(8)(mu-O)(4)], (Cp-R)(2)TiCl(2) and (Cp-R)CpTiCl(2) (R = CO(2)CH(3) and CO(2)CH(2)CH(3)), and three water-soluble titanocene-amino acid complexes-[Cp(2)Ti(aa)(2)]Cl(2) (aa = L: -cysteine, L: -methionine, and D: -penicillamine)-on the human colon adenocarcinoma cell line, HT-29. The capacity of [Ti(4)(maltolato)(8)(mu-O)(4)] to donate Ti(IV) to human apo-transferrin and its hydrolytic stability have been investigated and compared to the previously reported data on modified titanocenes with either hydrophilic ancillary ligands or the functionalized cyclopentadienyl ligands. Notably, the titanium-maltolato complex does not transfer Ti(VI) to human apo-transferrin at any time within the first seven days of its interaction, demonstrating the inert character of this species. Stability studies on these complexes have shown that titanocene complexes decompose at physiological pH while the [Ti(4)(maltolato)(8)(mu-O)(4)] complex is stable at this pH without any notable decomposition for a period of ten days. The antitumor activity of these complexes against colon cancer HT-29 cells was determined using an MTT cell viability assay at 72 and 96 h. The titanocene-amino acid and the (Cp-R)(2)TiCl(2)/(Cp-R)CpTiCl(2) (R = CO(2)CH(3)) complexes were not biologically active when human transferrin was absent; they also were inactive when human transferrin was present at dose-equivalent concentrations. (Cp-R)(2)TiCl(2) and (Cp-R)CpTiCl(2) (R = CO(2)CH(2)CH(3)) showed cytotoxic activity in HT-29 cells comparable to that which is displayed by titanocene dichloride. The titanium-maltolato complex had higher levels of cytotoxic activity than any other titanocene complex investigated. Transferrin may be important in protecting the titanium center from hydrolysis, but this may be achieved by selecting ligands that could result in hydrolytically stable, yet active, complexes.

Molybdenocene-oligonucleotide binding study at physiological pH using NMR spectroscopy and cyclic voltammetry.

The self-complementary oligonucleotide CGCATATATGCG was used as a model to establish the binding interactions of antitumor molybdenocene dichloride and DNA. The free dodecamer was first characterized using (1)H, NOESY, and DQF-COSY NMR experiments, which enable to pinpoint the guanines and adenines as well as the cytosines and thymines signals in the aromatic region. Molybdenocene dichloride was characterized in saline and buffer solutions as function of pH by (1)H NMR spectroscopy. In 10mM NaCl/D(2)O solution at pH of 6.5 and above, Cp(2)Mo(OD)(D(2)O)(+) is in equilibrium with its dimeric species, [Cp(2)Mo(mu-OH)(2)MoCp(2)](2+). In 25mM Tris/4mM NaCl/D(2)O at physiological pH, a new stable species is formed, coordinated by the buffer, Tris(hydroxymethyl)aminomethane. The interactions of molybdenocene dichloride species with CGCATATATGCG were studied at different pH. At pH 6.5, in 4mM NaCl/D(2)O solution, (1)H NMR spectra of CGCATATATGCG exhibit downfield shifts in the signals associated mainly to adenines and guanines, upon addition of molybdenocene dichloride. At pH 7.4, in 25mM Tris/4mM NaCl/D(2)O, molybdenocene species causes broadening and small downfield shifts to the purines and pyrimidine signals, suggesting that molybdenocene dichloride can get engaged in binding interactions with the oligonucleotide in a weak manner. (31)P NMR spectra of these interactions at pH 7.4 showed no changes associated to Mo(IV)-OP coordination, indicating that molybdenocene-oligonucleotide binding interactions are centered, most likely, on the bases. Cyclic voltammetry titration showed a 4.9% of molybdenocene-oligonucleotide interaction. This implicates that possible binding interactions with DNA are weak.

Study of titanocene-DNA and molybdenocene-DNA interactions by inductively coupled plasma-atomic emission spectroscopy.

Titanocene and molybdenocene dichlorides belong to a new class of organometallic antitumor agent. Although these complexes are isostructural, they behave differently under physiological conditions and hence have different mechanisms of action. It was initially proposed that these species interact with DNA, inhibiting the cell cycle. Recent studies using nucleotides and oligonucleotides suggest that molybdenocene does not bind DNA constituents at physiological pH whereas titanocene apparently interacts weakly with nucleotides through the phosphoesters. The evidence for this was, however, obtained under non-physiological conditions. Herein we report an analytical method that enables determination of the amount of metal bound to DNA under physiological conditions (pH 7.4 and buffer solution) and with sample preparation (dialysis) that resembles the cell environment. It was found that more than 90% titanium was bound to DNA after 46 h whereas binding of molybdenum was no more than 5%.