Mechanical integrity of dye-sensitized photovoltaic fibers

The development of photovoltaic (PV) devices based on dye-sensitized TiO₂-coated Ti fibers has opened up exciting possibilities for novel PV textile applications. The cohesion and adhesion of the TiO₂ layer are identified as crucial factors in maintaining PV efficiency during textile manufacture and weaving operations. The present work describes a systematic investigation of the corresponding damage mechanisms and their influence on the overall PV fiber performance during mechanical deformation. The results confirm that with proper control of the tension of the weft and in the warp, high PV efficiency woven textures are feasible using this technology.     

Cationic and radical polymerization of N-vinyl-2-phenylpyrrole: Synthesis of electroconducting,paramagnetic and fluorescent oligomers

Cationic polymerization of N-vinyl-2-phenylpyrrole (catalysts: Me₃SiCl, CF₃COOH, BF₃·OEt₂, HCl, WCl₆, FeCl₃, complex LiBF₄–dimethoxyethane, catalysts concentration 1–2 wt%, 20–70 °C, 24–48 h) affords oligomers (molecular weight 1400–1700) of a unexpected structure with alternating 2-phenylpyrrole and ethylydene units, the yields reaching 63%. The oligomers structure has been supported by isolation and identification of the corresponding dimer, N-vinyl-2-phenyl-5-[N-(2-phenyl-1H-pyrrol-1-yl)ethyl]-1H-pyrrole. Radical polymerization of the same monomer (AIBN, 1.5–4 wt%, 60–80 °C, 40–60 h or UV irradiation or both) gives oligomers (molecular weight 2100–3000) of normal structure having polyethene backbone with pendant 2-phenylpyrrole groups in up to 40% yields. The oligomers of both types are semiconductors (1.3 × 10^?6–3.6 × 10^?6 S/cm) after doping with I₂, paramagnetic (4.2 × 10¹⁷–8.7 × 10¹⁷ g^?1) and fluorescent in a near UV region (λ 355–363 nm, acetonitrile).     

Building energy performance: A LCA case study of kenaf-fibres insulation board

The paper presents a life cycle assessment of a kenaf-fibre insulation board following the international standards of the ISO 14040 series. Each life-cycle step has been checked, from kenaf production and board manufacture by an Italian firm, to use and disposal.     

Self-tuning reactive diffracting trees

Reactive diffracting trees are efficient distributed objects that support synchronization, by distributing sets of memory accesses to different memory banks in a coordinated manner. They adjust their size in order to retain their efficiency in the presence of different contention levels. Their adjustment is sensitive to parameters that have to be manually determined after experimentation. Since these parameters depend on the application as well as on the system configuration and load, determining their optimal values is difficult in practice. Moreover, the adjustments are done one level at a time, hence the cost of multi-level adjustments can be high.     

Surgical versus endovascular treatment in cerebral aneurysm. The opinion of a neurosurgeon]

The examination of deaths due to electricity may require a comparison between current marks on the body and the electrodes suspected to have caused them. Normally the identification of the responsible electrode is carried out by analysing metal traces on the current marks. We however examined the conductor for traces of biological material after experimentally produced current marks. The surfaces of the conductors were investigated using a low-power macroscope and burnt tissue could always be recognised. Subsequently, all electrodes were carefully swabbed, extracted with chelex and typed for short tandem repeat polymorphisms using PCR. This procedure was successful in all cases. Therefore, DNA analysis can be a powerful tool to supplement conventional scene reconstruction in cases of deaths due to electricity.     

Models of plane elements with various singular features

In the present article some problems of fracture mechanics are investigated with the help of polarization-optical methods. Experimental data obtained through static loading of plane models with singularities of various kinds are analyzed. The features and some paradoxes in the distribution of stresses in prefracture zones are revealed, and the control of several theoretical solutions of different authors is carried out. Applications of the research presented here are described.     

Combinatorial solid state chemistry by multitarget laser ablation: a way for the elaboration of new superconducting cuprates thin films?

Laser ablation by varying the number of consecutive laser pulses upon two targets, one superconducting YBa₂Cu₃O₇, the other insulating MCuO₂ (M=Sr, Ca), is used to build thin films of tuneable average compositions. Most of the samples are found to display high-T_c superconductivity with critical temperature generally higher than the 60 K of the ‘Cava phase’, the prototypic structure with two consecutive conducting CuO₂ planes and containing same types of atoms. The properties of the samples are not linearly dependent on the concentration of species coming from the insulating target. In addition, they depend not only on the ratio of the number of pulses on each target, but also on the number of consecutive pulses on each target. Thin films are characterized by temperature-dependent DC conductivity, X-ray diffraction, Castaing microprobe and infrared reflectivity spectroscopy. Present results suggest the robustness of high-T_c superconductivity, possibly related to a ‘Cava-phase-like’ skeleton.     

Tumor Extracellular Matrix Stiffness Promptly Modulates the Phenotype and Gene Expression of Infiltrating T Lymphocytes

The immune system is a fine modulator of the tumor biology supporting or inhibiting its progression, growth, invasion and conveys the pharmacological treatment effect. Tumors, on their side, have developed escaping mechanisms from the immune system action ranging from the direct secretion of biochemical signals to an indirect reaction, in which the cellular actors of the tumor microenvironment (TME) collaborate to mechanically condition the extracellular matrix (ECM) making it inhospitable to immune cells. TME is composed of several cell lines besides cancer cells, including tumor-associated macrophages, cancer-associated fibroblasts, CD4⁺ and CD8⁺ lymphocytes, and innate immunity cells. These populations interface with each other to prepare a conservative response, capable of evading the defense mechanisms implemented by the host’s immune system. The presence or absence, in particular, of cytotoxic CD8⁺ cells in the vicinity of the main tumor mass, is able to predict, respectively, the success or failure of drug therapy. Among various mechanisms of immunescaping, in this study, we characterized the modulation of the phenotypic profile of CD4⁺ and CD8⁺ cells in resting and activated states, in response to the mechanical pressure exerted by a three-dimensional in vitro system, able to recapitulate the rheological and stiffness properties of the tumor ECM.     

Entrepreneurial universities and the dynamics of academic knowledge production: A case study of basic vs. applied research in Belgium

This paper explores issues related to the impact of Science-Industry relationships on the knowledge production of academic research groups, in particular on the alleged shift to the more applied research end under the influence of business partners' needs. Our findings from a case study of the Belgian Katholieke Universiteit Leuven ((K.U. Leuven) show a significant steady growth over time of publications produced by academic research groups involved in University-Industry linkages, closely related to factors both internal and external to the university that have stimulated academic entrepreneurial behaviour. On an aggregated level for 1985-2000, basic research publications appear to be more present than applied ones, both in total numbers and in growth rates. Our findings show that applied and basic research publications generally rose together in the same year. No clear and generalised evidence of a shift towards the applied research end determined by the involvement in U-I linkages was found, the weak indications of such a shift within groups coming only for groups that have already high applied versus basic orientation. These results suggest that the academic research groups examined have developed a record of applied publications without affecting their basic research publications and, rather than differentiating between applied and basic research publications, it is the combination of basic and applied publications that consolidate the group's R&D potential. Accordingly, critical assessments of the University side of the emerging 'Triple Helix' need to take into account the dynamic nature of the research dimension.