Crystallization of some anorthite-diopside glass precursors

Anorthite and diopside have been obtained from complete devitrification of glasses belonging to the quaternary system MgO-CaO-Al₂O₃-SiO₂. Microstructure, the natural trend of the nucleation mechanism and kinetic studies on the crystallization phenomenon have been investigated by means of optical and electron microscopies, thermal and thermomechanical techniques and X-ray powder diffractometry. All the glasses investigated show a complete crystallization starting from a simple surface nucleation process. The activation energy for the crystallization process proved to be higher than that for viscous flow, leading to an important aspect modification in the sample during ceramization. Thermal stability and physical properties of both glass and glass-ceramic materials have been tested, suggesting the possible use of these materials in industrial application.     

Comorbidity of drug dependence and other mental disorders: a two-phase study of prevalence at outpatient treatment centres in Italy

The proposed mechanism of action of the antineoplastic drug 3-nitrobenzothiazolo[3,2-alpha]quinolinium chloride (NBQ-2) involves its interaction with DNA by intercalation and inhibition of topoisomerase II activity by arresting the enzyme in a covalent cleavage complex. In an attempt to identify some structural determinants for activity and develop a molecular structure/cytotoxicity correlation, four new structural analogs of the antitumor NBQ-2 were prepared and their cytotoxic activity and DNA binding properties were investigated. The cytotoxic activity was evaluated against six different human tumor cell lines: U937, K-562, HL-60, HT-29, HeLa, and A431. The results showed that these new drugs elicit pronounced cytotoxic effects against U937, K-562, HL-60 and A431 while HeLa and HT-29 were less sensitive to the new drugs. This apparent selectivity was different to that of m-AMSA, a drug currently used for cancer treatment. Since the interaction of NBQ-2 to DNA by intercalation has been proposed as the initial step leading to its antineoplastic activity, DNA binding and changes in DNA contour length induced by the new NBQ-2 structural analogs were also investigated using calf thymus and human DNA. The drug, 7-(1-propenyl)-3-nitrobenzimidazolo[3,2-alpha]quinolinium chloride (NBQ-59) was the most cytotoxic agent of the analog series (IC50 = 16 microM for HL-60 cells), however, it demonstrated the weakest binding to DNA (Kint = 0.9 x 10[5] M-1 for calf thymus DNA). NBQ-59 was also found to be a poor intercalator into the DNA double helix. Therefore, our results suggest that DNA binding is not the primary mechanism of drug action for this family of compounds. In addition structural determinants important for cytotoxicity of the benzazolo quinolinium chlorides were suggested by our results. In particular, the nitro group in the 3 position does not seem to be necessary for bioactivity, while substitutions in the benzazolo moiety have striking effects on the biological activity of the drugs.     

Postoperative enteral feeding does not prevent intestinal bacterial translocation, but reduces the rate of pulmonary infections in pigs undergoing total orthotopic small bowel transplantation

OBJECTIVE: To assess the effects of a non-elemental liquid diet on nutritional state, composition of bowel flora, intestinal translocation, and pulmonary infections after small bowel transplantation in pigs. DESIGN: Prospective randomised experiment. SETTING: Teaching hospital, Italy. MATERIAL: 32 female Large White pigs. INTERVENTIONS: Group 1 (n = 6) underwent small bowel transplantation, were treated with immunosuppression, and fed on commercial chow. Group 2 (n = 6) were treated similarly except that they were fed with an enteral feed through a tube gastrostomy starting on day 4 postoperatively. Group 3 (n = 6) were treated similarly to group 1 except that they had no immunosuppression, and Group 4 (n = 6) underwent orthotopic small bowel autotransplantation; 8 further pigs underwent a sham operation only to act as controls. MAIN OUTCOME MEASURES: Signs of rejection, graft-versus-host-disease, luminal bacterial overgrowth, bacterial translocation, pneumonia, and the pigs' nutritional state. RESULTS: All animals in group 3 showed signs of acute rejection. There was appreciable overgrowth of aerobic and anaerobic bacteria in all three groups after allotransplantation compared with controls. The counts of anaerobic bacteria were significantly lower in group 2 (enterally fed animals) compared with those given free access to commercial chow [mean (SD) 2.81 (1.39) log CFU/cm2 compared with 4.80 (1.65), p = 0.047]. Bacterial translocation developed to a similar degree after autografts and allografts and pneumonia developed in fewer animals after enteral feeding (1/6) than after conventional feeding (5/6) but the difference was not significant (p = 0.08, odds ratio 25.0, 95% confidence interval of odds ratio 1.20 to 521.13). Enterally fed animals also lost less weight than conventionally fed animals [2.32 (1.23) kg compared with 4.53 (1.74), p = 0.016]. CONCLUSIONS: Enteral feeding for up to a month slightly reduced the rate of pneumonia and resulted in a better nutritional state in pigs after small bowel transplantation. It had no effect on luminal bacterial overgrowth or translocation.     

HMAP– A temporal data model managing intervals with different granularities and indeterminacy from natural language sentences

The granularity of given temporal information is the level of abstraction at which information is expressed. Different units of measure allow one to represent different granularities. Indeterminacy is often present in temporal information given at different granularities: temporal indeterminacy is related to incomplete knowledge of when the considered fact happened. Focusing on temporal databases, different granularities and indeterminacy have to be considered in expressing valid time, i.e., the time at which the information is true in the modeled reality. In this paper, we propose HMAP (The term is the transliteration of an ancient Greek poetical word meaning “day”.), a temporal data model extending the capability of defining valid times with different granularity and/or with indeterminacy. In HMAP, absolute intervals are explicitly represented by their start,end, and duration: in this way, we can represent valid times as “in December 1998 for five hours”, “from July 1995, for 15 days”, “from March 1997 to October 15, 1997, between 6 and 6:30 p.m.”. HMAP is based on a three-valued logic, for managing uncertainty in temporal relationships. Formulas involving different temporal relationships between intervals, instants, and durations can be defined, allowing one to query the database with different granularities, not necessarily related to that of data. In this paper, we also discuss the complexity of algorithms, allowing us to evaluate HMAP formulas, and show that the formulas can be expressed as constraint networks falling into the class of simple temporal problems, which can be solved in polynomial time. Received 6 August 1998 / Accepted 13 July 2000 Published online: 13 February 2001     

The coordinated automatic voltage control of the Italian transmission Grid-part I: reasons of the choice and overview of the consolidated hierarchical system

Transmission network voltage regulation through coordinated automatic control of reactive powers is now becoming a challenging objective for many utilities and system operators (ISO or TSO) to achieve significant improvements in the security, quality, and efficiency of power system operation. This survey paper is concerned with application of Secondary and Tertiary Voltage Regulations (SVR and TVR), already operating in the Italian transmission network. The basic concepts behind SVR and TVR and the related hierarchical control system are first described in terms of system characteristics, main functions and design requirements. Cost/benefit analysis and comparison with alternative voltage control solutions are also provided in relation to the influence of power system restructuring process on the voltage ancillary service. More details about control system apparatuses and their field test results are provided in Part II.     

Integrated Inspection Scheduling and Maintenance Planning for Infrastructure Systems

Operation and maintenance of an infrastructure system rely on information collected on its components, which can provide the decision maker with an accurate assessment of their condition states. However, resources to be invested in data gathering are usually limited and observations should be collected based on their Value of Information (VoI). Assessing the VoI is computationally intractable for most applications involving sequential decisions, such as long‐term infrastructure maintenance. In this article, we propose an approach for integrating adaptive maintenance planning based on Partially Observable Markov Decision Process (POMDP) and inspection scheduling based on a tractable approximation of VoI. Two alternative myopic approaches, namely pessimistic and optimistic, are introduced, and compared theoretically and by numerical examples.     

Electrodeposition of nanostructured bioactive hydroxyapatite-heparin composite coatings on titanium for dental implant applications

In this paper we describe the one-pot fabrication of hydroxyapatite (HA)-heparin composites by electrodeposition onto Ti substrates and their characterisation in terms of structure, morphology, heparin content and bioactivity. HA coatings are well known and widely applied osteointegration enhancers, but post-implant healing rate in dental applications is still suboptimal: e.g. coagulation control plays a key role and the incorporation of an anticoagulant is considered a highly desirable option. In this study, we have developed an improved, simple and robust growth procedure for single-phase, pure HA-heparin films of thickness 1/3 μm. HA-heparin, forming nanowires, has the ideal morphology for bone mineralisation. Staining assays revealed homogeneous incorporation of sizable amounts of heparin in the composite films. The bioactivities of the HA and HA-heparin coatings on Ti were compared by HeLa cell proliferation/viability tests and found to be enhanced by the presence of the anticoagulant.     

Three-dimensional reconstructions of carotid bifurcation from CT images: evaluation of different rendering methods

The enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, involved in de novo cholesterol synthesis and cell-cycle progression, was identified as a potential mediator of the growth inhibitory effects of retinoic acid on human neuroblastoma. Lovastatin, a nonreversible inhibitor of HMG-CoA reductase, induced extensive cytotoxicity that was restricted to drug-resistant P-glycoprotein-expressing neuroblastoma cell lines. This response was potentiated by dibutyryl cyclic AMP but not retinoic acid. Patients with advanced-stage metastatic neuroblastoma often display an acquired chemoresistant phenotype, which may in part be mediated by P-glycoprotein. Our studies support the application or use of HMG-CoA reductase inhibitors as potential therapeutic agents in the treatment of these patients who are refractory to chemotherapy.