Understanding the Oxidative Properties of Nickel Oxyhydroxide in Alcohol Oxidation Reactions.

The NiOOH electrode is commonly used in electrochemical alcohol oxidations. Yet understanding the reaction mechanism is far from trivial. In many cases, the difficulty lies in the decoupling of the overlapping influence of chemical and electrochemical factors that not only govern the reaction pathway but also the crystal structure of the in situ formed oxyhydroxide. Here, we use a different approach to understand this system: we start with synthesizing pure forms of the two oxyhydroxides, ß-NiOOH and γ-NiOOH. Then, using the oxidative dehydrogenation of three typical alcohols as the model reactions, we examine the reactivity and selectivity of each oxyhydroxide. While solvent has a clear effect on the reaction rate of ß-NiOOH, the observed selectivity was found to be unaffected and remained over 95% for the dehydrogenation of both primary and secondary alcohols to aldehydes and ketones, respectively. Yet, high concentration of OH- in aqueous solvent promoted the preferential conversion of benzyl alcohol to benzoic acid. Thus, the formation of carboxylic compounds in the electrochemical oxidation without alkaline electrolyte is more likely to follow the direct electrochemical oxidation pathway. Overoxidation of NiOOH from the ß- to γ-phase will affect the selectivity but not the reactivity with a sustained >95% conversion. The mechanistic examinations comprising kinetic isotope effects, Hammett analysis, and spin trapping studies reveal that benzyl alcohol is oxidatively dehydrogenated to benzaldehyde via two consecutive hydrogen atom transfer steps. This work offers the unique oxidative and catalytic properties of NiOOH in alcohol oxidation reactions, shedding light on the mechanistic understanding of the electrochemical alcohol conversion using NiOOH-based electrodes.

Severe hemoptysis 6 years after coronary artery bypass grafting.

A patient with a history of coronary artery bypass grafting was admitted with severe hemoptysis. Bronchoscopy showed recent bleeding with clot formation in the lingular bronchus, but no tumor was visualized. Several biopsies of the underlying mucosa were negative. Coronary angiography showed patent venous and arterial bypass grafts. Selective angiography of the left internal mammary artery revealed one large and two smaller aberrant bronchial side branches, which probably caused the lingular hemorrhage. We performed embolization of the largest aberrant branch. After a follow-up of 3 months, hemoptysis had not recurred.

[Giant liposarcoma of the spermatic cord]. / Liposarcoma gigante del cordón espermático.

Liposarcomas (LS) are malignant mesenchymal tumours which develop in fatty tissues. They are basically found at the retroperitoneum where they are relatively frequent in adults. The most common type is myxoid LS which, although less malignant, has like any other LS a high incidence of local relapses. Primary myxoid liposarcoma of the spermatic cord is an unusual, low-aggressiveness tumour. Under natural development, it can reach large dimensions with only local symptomatology. Pre-operative diagnosis of the paratesticular tumour is often difficult to establish, cuenca the teste suénate be differentiated from the tumoral mass by physical examination. A diagnostic approach of paratesticular tumours, scarcely reported in the literature, can be made by means of a vascular study with radionuclides. The choice therapy is surgical, through orchiectomy and extensive local removal. Considering the frequency of local relapse of myxoid liposarcoma, long-term follow-up is recommended. This paper reports the unusual presentation of one case of primary myxoid LS of the spermatic cord with an intrascrotal mass of 38 x 24 cm weighing 4,950 gr which is exceptional not only because of the site's infrequency but also for its size.

[Myelolipoma of the adrenal gland: preoperative diagnostic approach]. / Mielolipoma de la glándula suprarrenal: aproximación diagnóstica preoperatoria.

The presence of a non-functioning tumor of the adrenal gland, which proved to be a myelolipoma, was the reason for a diagnostic approach to its etiology by means of the use of different imaging techniques (conventional radiology, angiography, E.C.O., C.A.T. and N.M.R.). As on most of the occasions, it was a question of a middle-aged patient, in this case a woman, displaying obesity and H.T.A. No symptom could be directly connected with the myelolipoma. We also used the clinical case to carry out a review of the different etiopathogenic and clinical aspects in order to lay down treatment guidelines.