First-order coil-globule transition driven by vibrational entropy.

By shifting the balance between conformational entropy and internal energy, polymers modify their shape under external stimuli, such as changes in temperature. Prominent among such transformations is the coil-globule transition, whereby a polymer can switch from an entropy-dominated coil conformation to a globular one, governed by energy. The nature of the coil-globule transition has remained elusive, with evidence for both continuous and discontinuous transitions, with the two-state behaviour of proteins as an instance of the latter.

Feedback topology and XOR-dynamics in Boolean networks with varying input structure.

We analyze a model of fixed in-degree random Boolean networks in which the fraction of input-receiving nodes is controlled by the parameter gamma. We investigate analytically and numerically the dynamics of graphs under a parallel XOR updating scheme. This scheme is interesting because it is accessible analytically and its phenomenology is at the same time under control and as rich as the one of general Boolean networks.

A national medical register: balancing public transparency and professional privacy.

The first aim of a medical registration scheme should be to protect patients. Medical registration boards currently offer variable information to the public on doctors' registration status. Current reform proposals for a national registration scheme should include free public access to professional profiles of registered medical practitioners.

Use of radioisotopic esophageal transit in the assessment of patients with symptoms of reflux and non-specific esophageal motor disorders.

The purposes of this study were to assess the esophageal clearance of a radioisotopic bolus in patients with symptoms of reflux and evaluate the impact of manometric abnormalities on scintigraphic esophageal transit. Esophageal clearance was assessed in a supine position and indicated by the retained radioactivity in the esophagus at 10, 20, 30 and 40 s after the ingestion of a liquid bolus labeled with 2 mCi 99 mTc-SC. The study included 214 consecutive patients with symptoms of reflux and 11 normal controls.

Recurrent gastric carcinoma causing pseudoachalasia: case report.

We report the case of a patient with a gastric remnant relapse of an antral carcinoma resected 5 years before and presenting with the clinical feature of a secondary achalasia (pseudoachalasia). In spite of the patient's 4-month history of dysphagia and weight loss that suggested a malignant lesion, barium swallow, repeated endoscopic biopsies and computed tomography (CT) scan of the upper abdomen did not reveal any abnormalities to indicate a recurrence. However, in the following months, because of worsening symptoms, a further CT scan was performed and revealed thickening of the cardia and gastric wall.