Two-time Green's functions and spectral density method in nonextensive quantum statistical mechanics

We extend the formalism of the thermodynamic two-time Green's functions to nonextensive quantum statistical mechanics. Working in the optimal Lagrangian multiplier representation, the q -spectral properties and the methods for a direct calculation of the two-time q Green's functions and the related q -spectral density ( q measures the nonextensivity degree) for two generic operators are presented in strict analogy with the extensive (q=1) counterpart. Some emphasis is devoted to the nonextensive version of the less known spectral density method whose effectiveness in exploring equilibrium and transport properties of a wide variety of systems has been well established in conventional classical and quantum many-body physics. To check how both the equations of motion and the spectral density methods work to study the q -induced nonextensivity effects in nontrivial many-body problems, we focus on the equilibrium properties of a second-quantized model for a high-density Bose gas with strong attraction between particles for which exact results exist in extensive conditions. Remarkably, the contributions to several thermodynamic quantities of the q -induced nonextensivity close to the extensive regime are explicitly calculated in the low-temperature regime by overcoming the calculation of the q grand-partition function.

Evaluation of rifaximin, placebo and lactulose in reducing the levels of benzodiazepine-like compounds in patients with liver cirrhosis: a pilot study

Benzodiazepine-like compounds (BZDs), either taken with the diet or synthesized by intestinal bacterial flora, may represent a precipitating factor for hepatic encephalopathy (HE) in cirrhotic patients. We evaluated whether a diet and/or treatment with rifaximin or lactulose can reduce serum concentrations of BZDs in 18 cirrhotic patients without HE. Patients were given a standard diet for 7 days to keep the dietary intake of BZDs constant and were then randomized to a 7-day treatment with rifaximin 1,200 mg/day, lactulose 10-20 g three times daily, or placebo. Blood samples were collected at enrollment, at the end of the diet and drug treatment periods, and 7 days after the drug was stopped (follow-up). Serum concentrations of BZDs were measured by a radioligand binding technique after high-performance liquid chromatography extraction and purification and were expressed as diazepam equivalents (DE). No change in serum BZD concentrations was observed during the diet, while a statistically significant decrease from 105.6 +/- 66.5 to 63.5 +/- 49.5 pmol DE/ml was achieved in rifaximin-treated patients (p < 0.05) but not in patients treated with lactulose or placebo. During the followup, serum BZD concentrations returned to 104.5 +/- 74.0 pmol DE/ml in rifaximin-treated patients (p < 0.05 vs. end-treatment values), while no significant change was observed in the lactulose- and placebo-treated patients. These data indicate that control of bacterial flora with cyclic administration of rifaximin plays a pivotal role in avoiding increased plasma concentrations of BZDs, which represent a precipitating factor for HE inpatients with severe liver disease.

Antiproliferative effects of Ceratonia siliqua L. on mouse hepatocellular carcinoma cell line

Extracts from pods and leaves of carob (Ceratonia siliqua L.) were tested for their ability to inhibit cell proliferation of mouse hepatocellular carcinoma cell line (T1). The two extracts showed a marked alteration of T1 cell proliferation in a dose-related fashion reaching the maximal effect at 1 mg/ml. Moreover, we demonstrated that leaf and pod extracts were able to induce apoptosis in T1 cell lines after 24-h treatment mediating a direct activation of the caspase 3 pathway. HPLC analysis revealed the presence of gallic acid, (-) epigallocatechin-3-gallate and (-) epicatechin-3-gallate in pod and leaf extracts, compounds well known to exert antiproliferative effects. Their concentration reached 6.28 mg/g in carob leaves and 1.36 mg/g in carob pods extract. The discovery that carob pod and leaf extracts contained antiproliferative agents could be of practical importance in the development of functional foods and/or chemopreventive drugs.

Extraction and purification from Ceratonia siliqua of compounds acting on central and peripheral benzodiazepine receptors

The presence of molecules with high affinity for central and peripheral benzodiazepine receptors was determined in the pod and leaves of Ceratonia siliqua (carob). The amount of the substances able to selectively bind the central benzodiazepine receptor recovered from carob pods and leaves was respectively 12.17 and 18.7 ng diazepam equivalent/g. The amount of compounds active on peripheral benzodiazepine receptor in both pods and leaves was higher in comparison with the central one, being 49.83 and 40.00 PK 11195 equivalent/g, respectively. In particular the compounds acting on peripheral benzodiazepine receptors were found to be extremely concentrated in the young leaves (2572.57 ng PK 11195 equivalent/g). The presence of substances with central benzodiazepine activity in carob extracts seems of great importance in view of the possibility to use carob extract as potential natural products with anxiolytic-sedative effects. Moreover, the prevalence in leaves of substances acting on peripheral benzodiazepine receptor suggests the possible utilisation of leave extracts as chemopreventive agents.

Two-time Green's functions and the spectral density method in nonextensive classical statistical mechanics

The two-time retarded and advanced Green's function technique is formulated in nonextensive classical statistical mechanics within the optimal Lagrange multiplier framework. The main spectral properties are presented and a spectral decomposition for the spectral density is obtained. Finally, the nonextensive version of the spectral density method is given and its effectiveness is tested by exploring the equilibrium properties of a classical ferromagnetic spin chain.