ABSTRACT
The oxidation of hydrocarbons is an important chemical transformation with relevance to biology and industry. Ni-catalyzed transformations are more scarce compared to Mn or Fe but have gained attention in recent years, affording efficient oxidations. Understanding the mechanism of action of these catalysts, including the detection and characterization of the active nickel-oxygen species, is of interest to design better catalysts. In this work, we undertake a theoretical study to unravel the mechanism of formation of the previously reported [Ni(OCl)(HL)]+ (H2) and how it activates C-H bonds. We disclose that the active species is indeed compound [Ni(O)(HL)]+, formed after homolytic cleavage of the O-Cl bond in H2 assisted by a chlorine radical. [Ni(O)(HL)]+ mediates C-H activation through an asynchronous concerted mechanism, in which the transition state is given by hydrogen atom transfer. Moreover, the electronic tuning of the ligand has a very modest impact on the stability and reactivity of the corresponding X2 species. Effective oxidation state analysis reveals an intriguing electronic structure of H2 and [Ni(O)(HL)]+, in which both the macrocycic HL ligand and the OCl and O ligands behave as redox noninnocent. Such redox activity leads to a fully ambiguous oxidation state assignation.
ABSTRACT
BACKGROUND AND OBJECTIVE: Both irritable bowel syndrome (IBS) and patent foramen ovale (PFO) have a similar prevalence in the general population, affect more commonly women and are related to comorbidities such as migraine. In IBS there are alterations in the metabolism of certain substances like serotonin. In the presence of PFO with a right- to left-shunt (RLS), a percentage of venous blood bypasses the lung filter and may increase these substances in blood. PATIENTS AND METHOD: A phone interview was done to determine the presence of IBS in patients previously attended for detection of RLS with transcranial Doppler ultrasound. The presence and grade of RLS was analyzed and compared with subjects without gastrointestinal symptoms (NoGI). Rome II criteria were used to diagnose IBS or other functional gastrointestinal disorder (FGD) and Venice 1999 consensus were used for the diagnosis of RLS. RESULTS: Thirthy-three (18.3%) of 180 interviewed patients had IBS and 62 (34.4%) other FGD. RLS was found in 41% of NoGI patients, 64% of patients with IBS and 68% of patients with other FGD (odds ratio [OR] = 2.56; p < 0.05 for SII, and OR = 3.06; p < 0.01 for other FGD). RLS with a massive pattern was registered in en 27% of NoGI patients, 39% of patients with IBS and 45% of patients with other FGD (OR = 1.73; p = 1 for IBS, and OR = 2.21; p < 0.05 for other FGD). CONCLUSIONS: We found a higher prevalence of cardiac RLS through a PFO in patients with IBS and other FGD. A possible etiopathogenic relationship must be considered in future studies.
Subject(s)
Foramen Ovale, Patent/complications , Irritable Bowel Syndrome/complications , Cross-Sectional Studies , Female , Foramen Ovale, Patent/physiopathology , Humans , Male , Middle AgedABSTRACT
FUNDAMENTO Y OBJETIVO: El síndrome de intestino irritable (SII) y el foramen oval permeable(FOP) tienen una prevalencia similar en la población general, afectan más a mujeres y se relacionancon otras enfermedades como la migraña. La presencia de FOP con cortocircuito (shunt) derecha izquierda (CDI) podría alterar el metabolismo de ciertas sustancias como la serotonina, muy relacionadas con el SII. Sin embargo, hasta la fecha no se ha estudiado la posibleasociación entre ambas entidades.PACIENTES Y MÉTODO: Se ha realizado una encuesta telefónica para determinar la presencia de SII enpacientes atendidos previamente para detección de CDI mediante ultrasonografía Doppler transcraneal.Se analizó la presencia y el grado de CDI y se los comparó con los de sujetos sin síntomas gastrointestinales (NoGI). Se utilizaron los criterios de Roma II para el diagnóstico de SII u otra enfermedad funcional gastrointestinal (EFGI), y el consenso de Venecia-1999 para el CDI.RESULTADOS: De 180 pacientes encuestados, 33 (18,3%) tenían SII y 62 (34,4%), otra EFGI.Tenían CDI un 41% de los NoGI, un 64% de los pacientes con SII y un 68% de los pacientes con otra EFGI (odds ratio [OR] = 2,56; p < 0,05 para SII, y OR = 3,06; p < 0,01 para otra EFGI). Los patrones masivos de CDI se registraron en el 27% de los NoGI, en el 39% de lospacientes con SII y en el 45% de los afectados por otra EFGI (OR = 1,73; p = 1 para SII, y OR = 2,21; p < 0,05 para otra EFGI).CONCLUSIONES: Se encontró mayor prevalencia de CDI cardíaco por FOP en pacientes con SII y otros trastornos funcionales digestivos. Su posible relación etiopatogénica debería considerarse en futuros estudios
BACKGROUND AND OBJECTIVE: Both irritable bowel syndrome (IBS) and patent foramen ovale (PFO) have a similar prevalence in the general population, affect more commonly women and are related to comorbidities such as migraine. In IBS there are alterations in the metabolism of certain substances like serotonin. In the presence of PFO with a right- to left-shunt (RLS), a percentageof venous blood bypasses the lung filter and may increase these substances in blood.PATIENTS AND METHOD: A phone interview was done to determine the presence of IBS in patientspreviously attended for detection of RLS with transcranial Doppler ultrasound. The presenceand grade of RLS was analyzed and compared with subjects without gastrointestinal symptoms (NoGI). Rome II criteria were used to diagnose IBS or other functional gastrointestinal disorder (FGD) and Venice 1999 consensus were used for the diagnosis of RLS.RESULTS: Thirthy-three (18.3%) of 180 interviewed patients had IBS and 62 (34.4%) other FGD. RLS was found in 41% of NoGI patients, 64% of patients with IBS and 68% of patients with other FGD (odds ratio [OR] = 2.56; p < 0.05 for SII, and OR = 3.06; p < 0.01 for otherFGD). RLS with a massive pattern was registered in en 27% of NoGI patients, 39% of patients with IBS and 45% of patients with other FGD (OR = 1.73; p = 1 for IBS, and OR = 2.21; p <0.05 for other FGD).CONCLUSIONS: We found a higher prevalence of cardiac RLS through a PFO in patients with IBS and other FGD. A possible etiopathogenic relationship must be considered in future studies
Subject(s)
Humans , Irritable Bowel Syndrome/epidemiology , Heart Septal Defects, Atrial/epidemiology , Irritable Bowel Syndrome/physiopathology , Heart Septal Defects, Atrial/physiopathology , Serotonin , Health SurveysABSTRACT
No disponible
Subject(s)
Humans , Female , Aged , Colitis, Ischemic/complications , Heart Septal Defects, Atrial/complications , EchocardiographySubject(s)
Intensive Care Units , Ultrasonography, Doppler, Transcranial , Arterial Occlusive Diseases/diagnostic imaging , Arterial Occlusive Diseases/therapy , Cerebral Arteries/diagnostic imaging , Cerebral Revascularization , Humans , Hypoxia, Brain/diagnostic imaging , Intracranial Embolism/diagnostic imagingABSTRACT
No disponible
Subject(s)
Humans , Sleep Apnea, Obstructive/etiology , Sleep Apnea, Obstructive/physiopathology , Foramen Magnum/abnormalitiesABSTRACT
No disponible
