Brønsted acid-catalyzed stereoselective [4+3] cycloadditions of ortho-hydroxybenzyl alcohols with N,N'-cyclic azomethine imines.

The first [4+3] cycloaddition of ortho-hydroxybenzyl alcohols has been established by making use of N,N'-cyclic azomethine imines as suitable 1,3-dipoles under Brønsted acid catalysis. By using this strategy, biologically important seven-membered heterocyclic scaffolds have been constructed in good yields and excellent diastereoselectivities (up to 92% yield, most >95 : 5 dr).

Radiological-pathological correlation of yolk sac tumor in 20 patients.

BACKGROUND: Yolk sac tumor (YST) is a rare tumor. Familiarity of its radiological characteristics may permit preoperative diagnosis and improve surgical management of patients. However, a detailed description of the imaging features of YST with pathological correlation in particular is scarce. PURPOSE: To investigate computed tomography (CT) findings of YSTs with pathological correlation. MATERIAL AND METHODS: CT images of 20 patients with pathologically proven YST were retrospectively reviewed. The location, size, margin, internal architecture, and pattern and degree enhancement of the lesion were evaluated. Radiological findings were correlated with pathological results. RESULTS: The locations of 20 tumors were distributed between the testis (n = 3), ovary (n = 6), sacrococcygeal area (n = 6), rectum (n = 1), and mediastinum (n = 4). The median age was 13 years. On CT images, all tumors were seen as oval (n = 14) or irregular (n = 6), well-defined (n = 16) or ill-defined (n = 4) masses with a mean size of 9.7 cm. The lesions were solid cystic (n = 10), entirely solid (n = 6), or predominantly cystic (n = 4). Intratumoral hemorrhage, calcification, and fatty tissue were seen in nine, three, and two tumors, respectively. Discontinuity of the tumor wall was seen in eight tumors. After contrast media administration, most tumors showed heterogeneous moderate to marked enhancement (n = 7) or heterogeneous marked enhancement (n = 9). Enlarged intratumoral vessels were seen in 17 tumors. CONCLUSION: YST usually appears as a large solid-cystic mass with intratumoral hemorrhage, capsular tear, marked heterogeneous enhancement, and enlarged intratumoral vessels on CT images. Intratumoral calcification and fatty tissue, although rare, may indicate a mixed YST containing teratoma component.

Effect of alcohol on diffuse axonal injury in rat brainstem: diffusion tensor imaging and aquaporin-4 expression study.

The aim of this study is to assess the effects of alcohol on traumatic brain injury by using diffusion tensor imaging (DTI) and evaluate aquaporin-4(AQP4) expression changes in rat brainstems following acute alcohol intoxication with diffuse axonal injury (DAI). We further investigated the correlation between the AQP4 expression and DTI in the brain edema. Eighty-five rats were imaged before and after injury at various stages. DTI was used to measure brainstem apparent diffusion coefficient (ADC) and fractional anisotropy (FA), with immunostaining being used to determine AQP4 expression. After acute alcoholism with DAI, ADC values of the brainstem first decreased within 6 h and then elevated. FA values began to decline by 1 h, reaching a minimum at 24 h after trauma. There was a negative correlation between ADC values and brainstem AQP4 expression at 6 h and positive correlation at 6 h to 24 h. Changes of ADC and FA values in DAI with acute alcoholism indicate the effects of ethanol on brain edema and the severity of axonal injury. The correlations between ADC values and the brainstem AQP4 expression at different time points suggest that AQP4 expression follows an adaptative profile to the severity of brain edema.

Production of a novel bioflocculant by Bacillus licheniformis X14 and its application to low temperature drinking water treatment.

A novel bioflocculant ZS-7 produced by Bacillus licheniformis X14 was investigated with regard to its synthesis and application to low temperature drinking water treatment. The effects of culture conditions including pH, carbon source, nitrogen source, temperature, inoculum size and shaking speed on ZS-7 production were studied. The purified bioflocculant was identified as a glycoprotein consisting of polysaccharide (91.5%, w/w) and protein (8.4%, w/w), with an approximate molecular weight of 6.89 x 10(4)Da. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) indicated the presence of amino, amide, carboxyl, methoxyl and hydroxyl groups. This bioflocculant showed good flocculating performance and industrial potential for treatment of low temperature drinking water, and the maximum removal efficiencies of COD(Mn) and turbidity were 61.2% and 95.6%, respectively, which were better than conventional chemical flocculants. Charge neutralization and bridging were proposed as the reasons for the enhanced performance based upon the experimental observations.