The relationship between crystalline disorder and electronic structure of Pd nanoparticles and their hydrogen storage properties

We investigated the relationship between crystalline disorder and electronic structure deviations of Pd nanoparticles (NPs) and their hydrogen storage properties as a function of their particle diameter (2.0, 4.6 and 7.6 nm) using various synchrotron techniques. The lattice constant of the 2.0 nm-diameter Pd NPs was observed to be larger than that of the 4.6 or 7.6 nm-diameter Pd NPs. With increasing particle diameter the structural ordering was improved, the lattice constant and atomic displacement were reduced and the coordination numbers increased, as determined using high-energy X-ray diffraction, reverse Monte Carlo modelling and X-ray absorption fine structure spectroscopy. The structural order of the core part of the larger NPs was also better than that of the smaller NPs. In addition, the bond strength of the Pd–H formation increased with increasing particle diameter. Finally, the surface order of the Pd NPs was related to enhancement of the hydrogen storage capacity and Pd–H bond strength.

Smaller Pd nanoparticles have a high degree of disordering and a lower coordination number on the surface part, which causes a change in electronic structure to have different hydrogen storage properties.     

Microscopic colitis. A review

Microscopic colitis (MC) is characterized by a triad of watery diarrhea, usually normal colonoscopic findings and typical microscopic findings. Two distinct histological forms of MC have been defined: lymphocytic colitis and collagenous colitis, but overlapping features may be present. The incidence of MC appears to be rising and in some countries it may account for as many as 10–20% of patients with non‐bloody watery diarrhea. The cause of MC remains unknown and is likely to be multifactorial. The pathogenesis is poorly defined, and numerous immunological abnormalities have been reported. MC is commonly associated with autoimmune diseases including celiac disease. Use of various medications, most notably non‐steroidal anti‐inflammatory agents and proton pump inhibitors, have been etiologically implicated but not firmly established as causative. In imperfect trials several agents have been reported to be effective in the treatment of MC; budesonide is the best studied and evidence supporting its effectiveness is the most persuasive. In cases of otherwise unexplained watery, non‐bloody diarrhea, MC should be considered and colonic biopsied specimens should be taken of normal‐appearing mucosa.     

Role of catecholamines in centrogenic cardiac arrhythmia induced by aconitine

1. Injection of 20 mug of aconitine into the lateral ventricle of dogs anaesthetized with pentobarbitone regularly induced cardiac irregularities and hypertension. The cardiovascular changes appeared within 5 min and lasted for about 90 min. Tachyphylaxis to the aconitine-induced cardiovascular effects was observed.2. The aconitine-induced arrhythmia and hypertension were centrogenic, for they were abolished or prevented by spinal transection (C(2)) or ganglionic blockade.3. Bilateral vagotomy as well as bilateral stellate ganglionectomy merely raised the threshold for arrhythmia without affecting the blood pressure response. The neural supply to the heart, therefore, does not seem to be the major pathway concerned in the genesis of the centrogenic cardiovascular effects of aconitine.4. The centrally evoked release of endogenous catecholamines from the adrenal glands was responsible for the aconitine-induced arrhythmia, since the arrhythmia could be blocked or prevented by prior reserpinization, bilateral adrenalectomy or thoracic splanchnic nerve section.5. alpha- and beta-adrenoceptive receptor blocking agents prevented or abolished the aconitine-induced arrhythmia in a manner similar to the catecholamine-induced arrhythmia.     

Emergency ultrasound evaluation of symptomatic nontraumatic pleural effusions

OBJECTIVE: We hypothesized that thoracic ultrasound (ThorUS) performed by emergency physicians would be a rapid and effective management tool for the evaluation of nontraumatic pleural effusion (PleurEff). METHODS: This is a prospective observational study of symptomatic adults presenting to an urban ED with suspicion of PleurEff. ThorUS was performed bilaterally in the upright position. Measurements included treating physician's procedural time requirements, pre- and posttest likelihood of PleurEff, and management changes. RESULTS: There were 59 patients who were entered into the study. Investigating physician's actual time to perform ThorUS was 2.19 minutes. After ThorUS, 48 (81%) patients had an increase and 11 (19%) had a reduction in likelihood of PleurEff with average absolute change in likelihood of PleurEff of 34% (P < .02). ThorUS changed management in 41% of cases; thoracentesis occurred most frequently. CONCLUSION: ThorUS performed by emergency physicians is a rapid and effective management tool for the evaluation of nontraumatic PleurEff in symptomatic ED patients.