RESUMEN
Organic radicals have long been suggested as candidates for organic magnets and components in organic spintronic devices. Herein, we demonstrate spin current emission from an organic radical film via spin pumping at room temperature. We present the synthesis and the thin film preparation of a Blatter-type radical with outstanding stability and low roughness. These features enable the fabrication of a radical/ferromagnet bilayer, in which the spin current emission from the organic radical layer can be reversibly reduced when the ferromagnetic film is brought into simultaneous resonance with the radical. The results provide an experimental demonstration of a metal-free organic radical layer operating as a spin source, opening a new avenue for the development of purely organic spintronic devices and bridging the gap between potential and real applications.
RESUMEN
The Overhauser effect in the dynamic nuclear polarization (DNP) of non-conducting solids has drawn much attention due to the potential for efficient high-field DNP as well as a general interest in the underlying principles that enable the Overhauser effect in small molecules. We recently reported the observation of 1H and 2H Overhauser effects in H3C- or D3C-functionalized Blatter radical analogs, which we presumed to be caused by methyl rotation. In this work, we look at the mechanism for methyl-driven Overhauser DNP in greater detail, considering methyl librations and tunneling in addition to classical rotation. We predict the temperature dependence of these mechanisms using density functional theory and spin dynamics simulations. Comparisons with results from ultralow-temperature magic angle spinning-DNP experiments revealed that cross-relaxation at temperatures above 60 K originates from both libration and rotation, while librations dominate at lower temperatures. Due to the zero-point vibrational nature of these motions, they are not quenched by very low temperatures, and methyl-driven Overhauser DNP is expected to increase in efficiency down to 0 K, predominantly due to increases in nuclear relaxation times.
RESUMEN
Point-of-care testing (POCT) of clinical biomarkers is critical to health monitoring and timely treatment, yet biosensing assays capable of detecting biomarkers without the need for costly external equipment and reagents are limited. Blood-based assays are, specifically, challenging as blood collection is invasive and follow-upprocessing is required. Here, we report a versatile assay that employs hydrogel microneedles (HMNs) to extract interstitial fluid (ISF), in a minimally invasive manner integrated with graphene oxide-nucleic acid (GO.NA)-based fluorescence biosensor to sense the biomarkers of interest in situ. The HMN-GO.NA assay is supplemented with a portable detector, enabling a complete POCT procedure. Our system could successfully measure four clinically important biomarkers (glucose, uric acid (UA), insulin, and serotonin) ex vivo, in addition, to accurately detecting glucose and UA in vivo.
Asunto(s)
Técnicas Biosensibles , Ácidos Nucleicos , Hidrogeles , Glucosa , Biomarcadores , Sondas de Ácido NucleicoRESUMEN
The Overhauser effect is unique among DNP mechanisms in that it requires the modulation of the electron-nuclear hyperfine interactions. While it dominates DNP in liquids and metals, where unpaired electrons are highly mobile, Overhauser DNP is possible in insulating solids if rapid structural modulations are linked to a modulation in hyperfine coupling. Herein, we report that Overhauser DNP can be triggered by the strategic addition of a methyl group, demonstrated here in a Blatter's radical. The rotation of the methyl group leads to a modulation of the hyperfine coupling to its protons, which in turn facilitates electron-nuclear cross-relaxation. Removal of the methyl protons, through deuteration, quenches the process, as does the reduction of the hyperfine coupling strength. This result suggests the possibility for the design of tailor-made Overhauser DNP polarizing agents for high-field MAS-DNP.
RESUMEN
We report a rare case of anterior spinal artery syndrome in the setting of acute cocaine use. A 31-year-old man presented to the hospital unarousable with leukocytosis and a positive toxicology screen for opioids, cocaine, benzodiazepines and cannabis. He was placed on intravenous naloxone. As the patient regained consciousness, he was found to have paraplegia, sensory loss below the level of T5, and urinary retention. MRI findings showed a signal intensity abnormality from the level of T1-4, highly suggestive of an acute ischemic spinal cord infarct. [Full article available at http://rimed.org/rimedicaljournal-2018-02.asp].
Asunto(s)
Síndrome de la Arteria Espinal Anterior/inducido químicamente , Trastornos Relacionados con Cocaína/complicaciones , Cocaína/toxicidad , Drogas Ilícitas/toxicidad , Adulto , Síndrome de la Arteria Espinal Anterior/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , MasculinoRESUMEN
We report a rare case of Hydralazine-induced ANCA associated glomerulonephritis with alveolar hemorrhage in the setting of acute Clostridium Difficile Infection. A 71-year-old Caucasian woman with hypertension, who was being treated with hydralazine 25 mg twice a day for six years, presented to the hospital with diarrhea, nausea, vomiting and anemia. She had acute kidney injury and urinalysis showed proteinuria, dysmorphic RBCs, and rare RBC cast. She was found to have Clostridium difficile colitis which was successfully treated. She became hypoxemic; CT scan findings showed bilateral pulmonary infiltrates. Broncho-alveolar lavage was consistent with pulmonary hemorrhage. Kidney biopsy revealed focal segmental necrotizing and diffuse crescentic glomerulonephritis, pauci-immune type (ANCA-associated). Hydralazine was discontinued and the patient was treated with corticosteroids, intravenous cyclophosphamide and plasmapheresis. To our knowledge, hydralazine-associated low complement in the setting of C-diff infection has not been previously reported. This is considered a potentially life-threatening condition requiring immediate discontinuation of the offending medication and expedited lifesaving measures. [Full article available at http://rimed.org/rimedicaljournal-2016-11.asp].
Asunto(s)
Antihipertensivos/efectos adversos , Infecciones por Clostridium/complicaciones , Glomerulonefritis/inducido químicamente , Hemorragia/inducido químicamente , Hidralazina/efectos adversos , Vasculitis/inducido químicamente , Corticoesteroides/uso terapéutico , Anciano , Anticuerpos Anticitoplasma de Neutrófilos/efectos adversos , Clostridioides difficile , Ciclofosfamida/uso terapéutico , Enterocolitis Seudomembranosa , Femenino , Glomerulonefritis/tratamiento farmacológico , Hemorragia/tratamiento farmacológico , Humanos , Hipertensión/tratamiento farmacológico , Riñón/patología , Tomografía Computarizada por Rayos X , Vasculitis/tratamiento farmacológicoRESUMEN
Over a period of 10 years a decrease was noted in the area of the Tuberculosis Dispensary of the Galatzi District, of the incidence through tuberculosis of the adult by approximately 50%, and an increase of the pulmonary cancer incidence three fold. The incidence curves of these two diseases, which were far apart 10 years ago, are much nearer now, and it may be presumed that in a not too remote future they will cross each other. The pneumophysiology network should be prepared further to face the increasing flow of patients with non-tuberculous diseases. With this view physicians should be re-cycled, and various types of specialists should be trained for cytologic diagnosis, and the technical equipment of antituberculous hospitals should be updated.