Un Nouveau Concept Baser Sur La Métallurgie Des Poudres Et Le Calcul Eléments Finis Pour Les Produits Biocompatibles

Résumé- Une nouvelle méthode de conception des produits biocompatibles comme les prothèses totales de hanche, est proposée. Des paramètres techniques sont prisent en compte sur le plan géométrique (design) et surtout sur le plan de matériau et calcul de résistance pour assurer la biocompatibilité de ce dernier. Cette méthodologie va permettre un gain en temps et en qualité.Mots clés- design, mode d’obtention, La métallurgie des poudres, processus, calcul de résistance, biomatériau, biocompatibilité

Increased Habitat Connectivity Homogenizes Freshwater Communities: Historical and Landscape Perspectives

Increases in habitat connectivity can have consequences for taxonomic, functional, and genetic diversity of communities. Previously isolated aquatic habitats were connected with canals and pipelines in the largest water development project in the US history, the Columbia Basin Project (CBP; eastern Washington, USA), which also altered environmental conditions; however, the ecological consequences are largely unknown. Using a historical dataset, we examined long-term patterns in zooplankton communities, water chemistry and clarity, testing the hypothesis that increased connectivity will result in taxonomic homogenization. Further, we tested contemporary drivers of communities using a comprehensive set of environmental and landscape variables. Waterbodies were sampled for zooplankton community composition as well as physical and chemical variables inside and outside the CBP using methods consistent with historical studies. We found significant declines in salinity inside the CBP, whereas changes in water clarity were prevalent across all waterbodies. Increased connectivity via canals homogenized zooplankton communities over time, as well as increasing regional richness. Other long-term changes in zooplankton communities may be related to climate change, invasive species, and land-use changes. Synthesis and applications. Though canals may offer species spatial refugia, homogenization may decrease resilience to environmental stressors. These new hybrid aquatic landscapes, or hydroscapes, should be considered carefully in future water development, including specific plans for monitoring of species and environmental conditions, as well as mitigation of undesirable conditions and/or non-native species

Optimising Well-Being and Learning Through Participatory Processes and Practices::an International Comparative Analysis of Ten Groundwork Case-Studies in Schools

The paper presents a theory of participation in systems of learning that emerges from our evidence gathered through partnerships between schools and the academy. The theory identifies young people need to endorse common principles of participation to include and respect all. Educational leaders’ evidence informed intervention strategies can positively impact young people’s inclusive and respectful participation in the action-research. The theory of participation conceptualises young people’s need for opportunities to pursue their ambitions and interests. Leaders’ intervention strategies may develop young people’s participation in attaining target examination outcomes to achieve their ambitions. We then develop the theory of participation regarding young people pursuing independent interests and ambitions in association with the other, to enable them to be drivers of social change. To do this they need to understand their future identity as potential consumers, employees, employers, and entrepreneurs with Small and Medium Enterprises (SME) that challenge public corporations in a variety of ways. We theorise how young people are well situated to build capacity in Europe and globally using the social media networks they have already developed. Our evidence identified five participation principals of inclusion, respect, trust in the search for truth, constructive cross-cultural critique of alternative world views to arrive at a shared multicultural world view, and the generation of new knowledge to enable the re-imagining of new futures where young people are drivers of social change. From these principals we developed a theory of practice and four global standards as guidelines. First, a commitment to inclusionary partnerships and communities of practice. Second, distributed autonomy across stakeholders in the institution characterized by respect for individuals’ associated rights and responsibilities. Third, constructive cross-cultural criticism underpinned by trust in a search for truth, using different group’s constructed identity schema’s to develop a shared multicultural world view. Fourth, the generation of new knowledge through structures and mechanisms to optimize participation

RecA-mediated strand invasion of DNA by oligonucleotides substituted with 2-aminoadenine and 2-thiothymine

Sequence-specific recognition of DNA is a critical step in gene targeting. Here we describe unique oligonucleotide (ON) hybrids that can stably pair to both strands of a linear DNA target in a RecA-dependent reaction with ATP or ATPγS. One strand of the hybrids is a 30-mer DNA ON that contains a 15-nt-long A/T-rich central core. The core sequence, which is substituted with 2-aminoadenine and 2-thiothymine, is weakly hybridized to complementary locked nucleic acid or 2′-OMe RNA ONs that are also substituted with the same base analogs. Robust targeting reactions took place in the presence of ATPγS and generated metastable double D-loop joints. Since the hybrids had pseudocomplementary character, the component ONs hybridized less strongly to each other than to complementary target DNA sequences composed of regular bases. This difference in pairing strength promoted the formation of joints capable of accommodating a single mismatch. If similar joints can form in vivo, virtually any A/T-rich site in genomic DNA could be selectively targeted. By designing the constructs so that the DNA ON is mismatched to its complementary sequence in DNA, joint formation might allow the ON to function as a template for targeted point mutation and gene correction

Asthma is not a common cause of severe chronic respiratory failure in non-smokers: ALOT study.

Background. Little is known about the long-term natural history of asthma and the long-term clinical and functional consequences in non-smoking patients. From a functional point of view, non-smoking asthmatic patients may have a significantly greater decline in forced expiratory volume in one second (FEV1) compared with nonasthmatic subjects and may develop chronic irreversible (fixed) airflow limitation. This has been related to the physiological consequences of chronic airway inflammation causing airway remodeling. However these lesions are all potentially reversible and there is little radiological evidence indicating lung destruction (pulmonary emphysema), which is potentially irreversible, in non-smoking asthmatics. Severe chronic respiratory failure is the major cause of mortality in patients with severe chronic lung diseases. Domiciliary long-term oxygen therapy (LTOT) is an accepted treatment for patients with severe chronic respiratory failure. Our reasoning, therefore, was that if asthma is a cause of severe chronic respiratory failure in nonsmokers we should be able to find non-smoking asthmatics within a large population of patients on LTOT. The aim of our study (Asthma and Long-term Oxygen Therapy, "ALOT") was to investigate the prevalence of non-smoking asthmatics in patients on LTOT in a multicentre, cross-sectional study. Methods. Between June and September 2003 we screened all subjects on long-term domiciliary oxygen therapy in three different hospitals in the North-East area of Italy (within the provinces of Ferrara and Bologna). Taken collectively, we have found one-hundred and eighty-four patients on LTOT. We have reviewed their clinical data (age, sex, smoking, history and physical examination, arterial blood gas analysis, pulmonary function). Results. 114 patients (all smokers) fulfilled the diagnostic criteria for COPD. Seventy patients (all smokers) had other diseases. We were unable to find any non-smokers in our screened population of subjects on long-term domiciliary oxygen therapy. Furthermore, there was no past history of asthma and/or acute wheezing episodes in either of the patient groups. Conclusions. This data suggests that asthma is an uncommon cause of severe chronic respiratory failure necessitating long-term domiciliary oxygen therapy in nonsmokers and supports the current consensus that asthma and COPD are different diseases with differing stages of severity and the concept that long-term avoidance of active smoking is fundamental for the prevention of severe chronic respiratory failure

Clean thermal decomposition of tertiary-alkyl metal thiolates to metal sulfides: Environmentally-benign, non-polar inks for solution-processed chalcopyrite solar cells

We report the preparation of Cu2S, In2S3, CuInS2 and Cu(In,Ga)S2 semiconducting films via the spin coating and annealing of soluble tertiary-alkyl thiolate complexes. The thiolate compounds are readily prepared via the reaction of metal bases and tertiary-alkyl thiols. The thiolate complexes are soluble in common organic solvents and can be solution processed by spin coating to yield thin films. Upon thermal annealing in the range of 200-400 ??C, the tertiary-alkyl thiolates decompose cleanly to yield volatile dialkyl sulfides and metal sulfide films which are free of organic residue. Analysis of the reaction byproducts strongly suggests that the decomposition proceeds via an SN1 mechanism. The composition of the films can be controlled by adjusting the amount of each metal thiolate used in the precursor solution yielding bandgaps in the range of 1.2 to 3.3 eV. The films form functioning p-n junctions when deposited in contact with CdS films prepared by the same method. Functioning solar cells are observed when such p-n junctions are prepared on transparent conducting substrates and finished by depositing electrodes with appropriate work functions. This method enables the fabrication of metal chalcogenide films on a large scale via a simple and chemically clear process.ope

Dinamika funkcije pluća kod azbestne bolesti

As a rule, asbestosis is a disease of workers who are occupationally exposed to inhalation of asbestos dust, leaving permanent alterations on the lung parenchyma or pleura. In our ten-year study, we investigated 318 workers with pleural asbestosis from whom we took medical history which included occupational exposure to asbestos, radiological examinations and lung function, which is mandatory for the diagnosis and the follow up of the disease. We analysed functional parameters such as forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1) and intermediate forced expiratory flow at 25 % to 75 % (FEF25 %-75 %). In addition, we investigated the predicted values of functional parameters according to smoking and non-smoking habits. We found a significant reduction in vital capacity, particularly in smokers after 25 years of exposure to asbestos. During the first 15 years, values of vital capacity on the group basis remained inside the 80 % of the normal values and were not significant for assessing the dynamics of the lung function. To better assess the effects of occupational asbestos exposure, it is necessary to interpret lung function data not only on the group basis, but also for each subject individually.Azbestoza je bolest izazvana udisanjem azbestnih čestica koje ostavljaju trajne promjene na parenhimu pluća i/ili pleuri. Dijagnoza se postavlja na osnovi anamnestičkih podataka, uvidom u profesionalnu izloženost azbestu i radiološkom obradom te patohistološkom potvrdom promjena na plućima i/ili pleuri. Funkcionalna obrada pluća obavezna je u postavljanju dijagnoze i praćenju bolesti. Tijekom desetogodišnjeg istraživanja funkcionalno smo obradili 318 osoba profesionalno izloženih azbestu s dokazanom azbestozom pleure. Analizirane su vrijednosti funkcionalnih parametara, i to forsiranoga vitalnog kapaciteta (FVC), forsiranoga ekspiracijskog volumena u prvoj sekundi (FEV1) i srednjega ekspiracijskog protoka (FEF25 %-75 %). Dokazan je statistički signifikantan pad vrijednosti FVC i FEV1. Dodatno smo istražili vrijednosti funkcionalnih parametara kod naših ispitanika s navikom pušenja i nepušača. U obje skupine prisutno je značajno sniženje vrijednosti vitalnog kapaciteta tijekom istraživanja, s tim da nakon 25 godina izloženosti azbestu kod pušača dolazi do naglog pada vrijednosti vitalnog kapaciteta u odnosu na nepušače. Bitno je uočiti da tijekom prvih 15 godina vrijednosti vitalnog kapaciteta ostaju unutar 80 % normalnih vrijednosti te nemaju značenja za praćenje dinamike funkcije pluća kod azbestne bolesti. Individualnim praćenjem profesionalno izloženih radnika ostvaruje se bolji uvid u dinamiku funkcije pluća kod azbestne bolesti

Synthesis of novel MMT/acyl-protected nucleo alanine monomers for the preparation of DNA/alanyl-PNA chimeras

Alanyl-peptide nucleic acid (alanyl-PNA)/DNA chimeras are oligomers envisaged to be beneficial in efficient DNA diagnostics based on an improved molecular beacon concept. A synthesis of alanyl-PNA/DNA chimera can be based on the solid phase assembly of the oligomer with mixed oligonucleotide/peptide backbone under DNA synthesis conditions, in which the nucleotides are introduced as phosphoramidites, whereas the nucleo amino acids make use of the acid labile monomethoxytrityl (MMT) group for temporary protection of the α-amino groups and acyl protecting groups for the exocyclic amino functions of the nucleobases. In this work, we realized for the first time the synthesis of all four MMT/acyl-protected nucleo alanines, achieved by deprotection/reprotection of the newly synthesized Boc/acyl intermediates, useful monomers for the obtainment of (alanyl-PNA)/DNA chimeras by conditions fully compatible with the standard phosphoramidite DNA synthesis strategy