Towards Supramolecular Catalysis with Small Self-assembled Peptides

Self-assembly of small peptides offers unique opportunities for the bottom-up construction of supramolecular catalysts that aim to emulate the efficiency and selectivity of natural enzymes. Small, information-rich, simple molecules based on amino acids can self-organise autonomously into complex systems with emergent catalytic properties. The power of noncovalent interactions can be used to construct supramolecular peptidic tertiary structures. Moreover, specific functional groups present in amino acid side-chains may present either a catalytic activity by themselves or be able to bind cofactors such as metal ions. In this scenario, although relevant progress has been achieved in recent years, promising applications in biomaterials science are foreseen. In this review, we discuss the state-of-the-art of this approach at the interface between supramolecular chemistry and peptide science.     

RTOS modeling in SystemC for real-time embedded SW simulation: A POSIX model

SystemC is committed to support the requirements for an integrated, HW/SW co-design flow, thus allowing the development of complex, multiprocessing, Systems-on Chip (MpSoC). To make this possible, efficient modeling and simulation methodologies for Real-Time, Embedded (RT/E) SW in SystemC have to be developed, so that the designer can verify and refine the application SW together with the rest of the elements of the platform. Accurate modeling of the application SW requires an accurate model of the RTOS. Nevertheless, low-level, dynamic timing characteristics of the RTOS such as time-slicing, priority-based preemptive scheduling, interrupts and exceptions do not have a direct implementation in SystemC. In this paper, techniques are proposed to accurately model the detailed RTOS functionality on top of the SystemC execution kernel. The model allows timed-simulation and refinement of the RT/E SW code in SystemC. The simulation technology has been applied to the development of a high-level, POSIX simulation library in SystemC. The library allows the designer a fast, sufficiently accurate, timed simulation of the application SW running on top of POSIX. As most current RTOSs support this standard, the library is portable to different development frameworks. The library provides the required infrastructure for a complete, multiprocessing, HW/SW co-simulation environment at different abstraction levels using SystemC.     

The scenario of Brazilian health sciences in the period of 1981 to 1995

Ensuing a previous study of Brazilian sciences production for the period 1981–95, health sciences were taken apart for scrutiny. ISI data was obtained in an aggregate format comprising 40 health research fields recording their yearly number of papers, proportion out of the country, proportion out of the field, and impact relative to field. Simple linear regression was used to examine time trends in production and impact of research fields. A complementary variable representing growth trend was computed as the regression slope. Data were then analysed by means of Factor and Correspondence Analysis. Results allowed the production of location maps of research fields so that hierarchy and relationships among them could be examined in the form of geometric distances. It was found that health sciences represent 42% of the Brazilian scientific production and that their trends in both production and impact do not differ from other sciences taken altogether. Measurements of production were found negatively correlated with impact and factor analysis revealed that the major distinction between fields is attributable to production (64% of measurement variations against 19% due to impact). Experimental Biology & Medicine largely exceeds other fields in production, though at ordinary levels of impact. Correspondence analysis refined the study of impact allowing the identification of the best performers as Clinical Immunology & Infectious Diseases, Environmental & Social Medicine, and Radiology & Nuclear Medicine. The information provided can advise national policy makers on science & technology about priorities concerning the improvement of the country's competitiveness.     

The importance of clinical symptoms and signs in the diagnosis of community-acquired pneumonia

PURPOSE: 118 Patients with suspected obstruction of the biliary tract of pancreatic duct were examined to evaluate the accuracy of MR cholangiopancreatography (MRCP) in comparison with diagnostic findings in endoscopic retrograde cholangiopancreatography (ERCP). METHODS: Using a 0.5-Tesla MR imaging system (FLEXART, Toshiba) and a QD body-coil, a recently developed heavily T2-weighted fast acquisition spin echo sequence (FASE) was applied. In this FASE sequence two significant features are implemented. A fast spin-echo (SE) sequence allows a large number of echos and conjugate K-space filling speeds up data acquisition. Thus, the acquisition time of single-shot breath-hold images takes only 3 seconds, which makes MRCP a feasible technique even in elderly or suffering patients. There is no need for time-consuming postprocessing procedures. RESULTS: In all MRCP examinations images of satisfactory quality were obtained. In cases of obstruction of the biliary or pancreatic duct, locations and lengths of stenoses were correctly demonstrated. Gallstones within the gallbladder or in the extrahepatic bile ducts were also properly visualised in MRCP. Stenoses caused by non-depicted pancreatic carcinoma, gallbladder carcinoma, or segmental pancreatitis were reliably shown. CONCLUSION: Even if MRCP will not replace ERCP, a number of clinical applications for non-invasive MRCP examination arise: primary diagnosis in patients with obstructive jaundice, obstruction of the biliary or pancreatic duct, if ERCP is not possible due to anatomic reason and in patients scheduled for laparoscopic cholecystectomy.     

Brazilian sciences and government funding at the State of São Paulo

The State of São Paulo plays an important role in national research activities. The Foundation for the Support of Research of São Paulo State (FAPESP) is commissioned to manage funds for these activities. The profile of Brazilian sciences is investigated and contrasted to FAPESP's investments. ISI date relative to years 1981 to 1995 are analysed through multivariate methods (Factor and Cluster Analysis) as to provide weighted ranks of research fields, relationships among them as geometric distances, and group classification. This information is compared to public reports on FAPESP's expenditures. Brazilian scientific production grows at 244 papers/year in the period, and its global share is almost doubled. Impact shows no trend. Best performers are from exact and biological sciences. Though impact varies greatly among research fields, their major distinctive feature is magnitude of production. The six top research fields identified (Physics, Biology &; Biochemistry, Clinical Medicine, Engineering, Chemistry, Plant &; Animal Sciences) were found to equally be the prime beneficiaries FAPESP's investments. The Brazilian scenario is one of increasing production under an international pattern. This trend is not accompanied by changes in impact. As a corollary, volume of publications rises as an important issue. Public investments from São Paulo State adequately conform this scenario giving reassurance that resouces are not being squandered.     

Driving Factors of High Performance in Brazilian Management Sciences for the 1981–1995 Period

As a corollary of former studies, high performance in Brazilian Management Sciences during the period of 1981 to 1995 is put to scrutiny. Information on the 66 papers registered to this field in the ISI databases for this time interval were retrieved, edited and processed as to elicit patterns.Occurrences of highly cited papers seemed haphazard but the presence of collaborative work consistently emerged as an important driving factor for good performance. International collaboration showed the most expressive impact over chances of citation but any form of collaboration seemed to have some effect, even those represented by single authors with double allegiance. Simple addition of authors, nonetheless, had no effect, and thus collaboration involving authors of common institutional affiliation showed the performance of single authored papers.Cluster analysis allowed the identification of patterns of performance, and groups of best performers showed higher levels of international collaboration. The institutional composition of the clusters is presented.     

Effect of Hyaluronic Acid on the Self-Assembly of a Dipeptide-Based Supramolecular Gel

The combination of polymers and low molecular weight (LMW) compounds is a powerful approach to prepare new supramolecular materials. Here we prepare two-component hydrogels made by a well-known and biologically active polymer, hyaluronic acid ( HA ), and a dipeptide-based supramolecular gelator. We undertake a detailed study of materials with different compositions including macroscopic (hydrogel formation, rheology) and micro/nanoscopic characterization (electron microscopy, X-ray powder diffraction). We observe that the two components mutually benefit in the new materials: a minimum amount of HA helps to reduce the polymorphism of the LMW network leading to reproducible hydrogels with improved mechanical properties; the LMW component network holds HA without the need for an irreversible covalent crosslinking. These materials have a great potential for biomedical application as, for instance, extracellular matrix mimetics for cell growth. As a proof of concept, we have observed that this material is effective for cell growth in suspension and avoids cell sedimentation even in the presence of competing cell-adhesive surfaces. This may be of interest to advanced cell delivery techniques.