Effect of ZnSO4, MnSO4 and FeSO4 on the Partial Hydrogenation of Benzene over Nano Ru-Based Catalysts.

Nano Ru-based catalysts, including monometallic Ru and Ru-Zn nanoparticles, were synthesized via a precipitation method. The prepared catalysts were evaluated on partial hydrogenation of benzene towards cyclohexene generation, during which the effect of reaction modifiers, i.e., ZnSO4, MnSO4, and FeSO4, was investigated. The fresh and the spent catalysts were thoroughly characterized by XRD, TEM, SEM, XPS, XRF, and DFT studies. It was found that Zn2+ or Fe2+ could be adsorbed on the surface of a monometallic Ru catalyst, where a stabilized complex could be formed between the cations and the cyclohexene. This led to an enhancement of catalytic selectivity towards cyclohexene. Furthermore, electron transfer was observed from Zn2+ or Fe2+ to Ru, hindering the catalytic activity towards benzene hydrogenation. In comparison, very few Mn2+ cations were adsorbed on the Ru surface, for which no cyclohexene could be detected. On the other hand, for Ru-Zn catalyst, Zn existed as rodlike ZnO. The added ZnSO4 and FeSO4 could react with ZnO to generate (Zn(OH)2)5(ZnSO4)(H2O) and basic Fe sulfate, respectively. This further benefited the adsorption of Zn2+ or Fe2+, leading to the decrease of catalytic activity towards benzene conversion and the increase of selectivity towards cyclohexene synthesis. When 0.57 mol·L-1 of ZnSO4 was applied, the highest cyclohexene yield of 62.6% was achieved. When MnSO4 was used as a reaction modifier, H2SO4 could be generated in the slurry via its hydrolysis, which reacted with ZnO to form ZnSO4. The selectivity towards cyclohexene formation was then improved by the adsorbed Zn2+.

Radiology of Osteoporosis: Old and New Findings.

Osteoporosis, a systemic metabolic disease of bone, is characterized by low bone mass and altered trabecular pattern, leading to increased risk of fractures. It increases in prevalence with age, especially in postmenopausal women, and can have other secondary causes. Radiologic evaluation of osteoporosis has historically used conventional radiography, which demonstrates cortical thinning, increased radiolucency, and altered trabecular patterns, and also aids in assessing vertebral fractures. Many indexes have been devised, such as the Saville index for the degree of radiolucency, and the Genant grading system for vertebral fractures. Other grading systems have been produced to assess the change in trabecular patterns in the proximal femur and the calcaneus. Differentiating osteoporosis from other bone disorders, such as malignancy, endocrinologic or metabolic diseases, and other causes is also important. Bone scintigraphy, although useful in excluding other metabolic bone diseases and determining the age of vertebral fractures, is less useful for diagnosis of osteoporosis. More recently, the measurement of Hounsfield units on multidetector computed tomography has emerged as a possible modality for opportunistic screening of osteoporosis when being performed for other indications.

Magnetic resonance imaging of traumatic and non-traumatic brachial plexopathies.

Adult-onset brachial plexopathy can be classified into traumatic and non-traumatic aetiologies. Traumatic brachial plexopathies can affect the pre- or postganglionic segments of the plexus. Non-traumatic brachial plexopathies may be due to neoplasia, radiotherapy, thoracic outlet syndrome and idiopathic neuralgic amyotrophy. Conventional magnetic resonance imaging (MRI) is useful to localise the area of injury or disease, and identify the likely cause. This review discusses some of the common causes of adult-onset brachial plexopathy and their imaging features on MRI. We also present a series of cases to illustrate some of these causes and their MRI findings.