Origin of the E/Z Selectivity in the Synthesis of Tetrasubstituted Olefins by Wittig Reaction of α-Fluorophosphonium Ylides: An Explanation for the Low Stereoselectivity Observed in Reactions of α-Alkoxy Aldehydes.

A series of tetrasubstituted fluoroalkenes were synthesized in good yield and high E/Z selectivity (up to 96/4) by Wittig reaction between α-heterosubstituted ketones and α-fluorophosphonium ylides. A detailed study of factors that control stereoselectivity in these reactions shows that stereoselectivity is the result of stabilizing CH···F and N···C═O interactions in the addition TS leading to the E isomer. This analysis provides a rationale for the observed decrease in selectivity for reactions of stabilized ylides with α-alkoxy aldehydes.

Correlations between cognitive, behavioural and psychological findings and levels of vitamin B12 and folate in patients with dementia.

Background: Associations between low levels of folate and vitamin B12 and cognitive impairment in patients with dementia have been reported. Some studies revealed correlations between low levels of vitamin B12 and behavioural and psychological signs and symptoms of dementia (BPSD) in Alzheimer's disease (AD) patients. Given the lack of studies in frontotemporal dementia (FTD) and on folate and given the methodological shortcomings of former publications, we set up a prospective study.

Sarcoidosis and sarcoid-like reaction following Hodgkin's disease. Report of two cases.

The occurrence of a sarcoidosis associated with Hodgkin's disease is an infrequent but well-described event. Moreover it has been described for many decades that some malignancies may present with simultaneous granulomatous manifestations named sarcoid-like reactions. To differentiate sarcoidosis from the sarcoid-like reactions is not an easy step in the final diagnosis.

Imaging of large vessel vasculitis with (18)FDG PET: illusion or reality? A critical review of the literature data.

Fluorine-18 fluorodeoxyglucose positron emission tomography ((18)FDG PET) plays a major role in the management of oncology patients. Owing to the singular properties of the glucose tracer, many patients suffering from non-malignant diseases such as inflammatory or infectious diseases may also derive clinical benefit from the appropriate use of metabolic imaging. Large vessel vasculitides such as giant cell arteritis and Takayasu arteritis are other examples that may potentially extend the field of (18)FDG PET indications.

Workflow in nuclear medicine.

This paper discusses a workflow management system for nuclear medicine. It augments the more conventional PACS with automatic transfer of studies along the chain of activities making up an examination in nuclear medicine. A prototype system has been designed, built, and installed in a department of nuclear medicine, active in a network of hospitals.