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The use of wood in timber bridges is increased over the past 20 years, mainly since wood is a renewable and sustainable resource. Nevertheless wood is a natural engineering material that is prone to deterioration caused by fungi decay, insect attack and temperature. For wood and wooden bridges there is in fact a strong correlation between durability of the material and bearing capacity. Deformations in a timber structure are often a good indicator of the structural condition. Within this context, in this study some structural issues dealing with the design of a timber bridge for pedestrians are investigated. In a first step, the bridge shape is designed taking into account various aspects: timber as a bridge material; properties of structural wood products; rain systems for preservation and protection; wearing surfaces for timber decks in order to ensure durability; static and dynamic loads; static scheme. In a second step, the bridge shape is optimized by a procedure based on the calibration of natural modes of vibration.

Several biomaterials have recently been developed to address the challenge of osteochondral regeneration. Among these, chitosan holds promises both for cartilage and bone healing. The aim of this in vivo study was to evaluate the regeneration potential of a novel hybrid magnesium-doped hydroxyapatite (MgHA), collagen, chitosan-based scaffold,whichwas tested in a sheepmodel to ascertain its osteochondral regenerative potential, and in a rabbitmodel to further evaluate its ability to regenerate bone tissue. Macroscopic, microtomography, histology, histomorphometry, and immunohistochemical analysis were performed. In the sheepmodel, all analyses did not show significant differences compared to untreated defects (p > 0.05), with no evidence of cartilage and subchondral bone regeneration. In the rabbit model, this bone scaffold provided less ability to enhance tissue healing compared with a commercial bone scaffold. Moreover, persistence of scaffold material and absence of integration with connective tissue around the scaffolds were observed. These results raised some concerns about the osteochondral use of this chitosan composite scaffold, especially for the bone layer. Further studies are needed to explore the best formulation of chitosan-reinforced composites for osteochondral treatment.

Currently, chemotherapy combined with surgery and radiation therapy is the most effective treatment for cancer. At the same time, the use of this method is accompanied by serious side effects caused by the lack of specificity of most chemotherapeutic agents. In this regard, the development of drug delivery systems (DDS) capable of addressing a chemotherapeutic agent to cancer cells, as well as its controlled release, is a promising approach for the effective treatment of cancer. The aim of the study is to synthesize a new DDS based on surface-modified microparticles of zero-valent iron, to study its properties as a carrier of a chemotherapeutic agent (encapsulation efficiency, loading capacity, possibility of controlled release of a chemotherapeutic agent) and safety. Materials and methods. The microparticles were synthesised by reduction of iron (III) chloride with sodium borohydride followed by in situ surface modification by 4-carboxybenzyldiazonium tosylate. To confirm the occurrence of the reaction, FTIR spectroscopy (Nicolet iS5 Infrared Spectrometer (Thermo Scientific, USA)) was used. Hydrodynamic diameter and surface charge of the microparticles in solution were investigated by dynamic light scattering (DLS) and z-potential. DOX release studies were performed in simulated physiological conditions (pH 3.3; 5.5; 7.4) to evaluate the effect of the external pH on the release rate. Release studies under ultrasound irradiation were performed simultaneously in the same conditions. The effect of surface modification on encapsulation efficiency was evaluated at various pH values (3.3; 5.5; 7.4) and doxorubicin concentrations (0.2; 0.35; 0.5; 0.75; 1.0 mg/ml). To demonstrate the safety of the developed system, cytotoxicity studies were performed on HeLa cell lines (ATCC® CCL-2™). Results. An original method of preparation of the drug carrier, based on iron zero-valent microparticles with covalently attached chitosan (Fe-CS) on their surface was proposed. Prepared microparticles demonstrated high encapsulation efficiency, drug loading capacity of DOX (0.9 mg per 1 mg of Fe-CS microparticles), low cytotoxicity and also a possibility to modulate the release rate by ultrasound irradiation and by changing pH of the external environment. Conclusion. A carrier based on microparticles of zero-valent iron with covalently attached to the surface chitosan (Fe-CS) was obtained. The efficiency of encapsulation, the loading capacity of doxorubicin was determined and the possibility of its controlled release under the influence of an ultrasonic field at different pH values was confirmed. In an in vitro experiment on the HeLa cell line (ATCC® CCL-2™), no toxicity was established for all samples (Fe0, Fe-COOH и Fe-CS), regardless of their concentration. © 2019 Siberian State Medical University. All rights reserved., TPU development project

– Implementation of scientific subjects (mathematics, physics, chemistry, and natural science) for a primary science education degree programme has represented a cultural challenge to the Italian scientific community in the last years. In the international context, there are still few articles in the literature available concerning teachers working at this primary level, in spite of the fact that children’s first encounter with science could play a decisive role in creating a vocation for science in at an early age. This work proposes to consider humanistic education as both a scientific and literary formation: according to this interpretation, introducing children to symbolic thought in school education stimulates involvement on the part of the pupils and leads them through a completion process that includes several perspectives on the world (expressive, linguistic, geometric and quantitative). The authors describe herein the application of this approach to chemistry teaching through significant examples showing integration of institutional content with historical and epistemological aspects; the results obtained during the years 2014-17 are discussed from a qualitative point of view at the Primary Education Department at Roma Tre University. Riassunto – Il rafforzamento della componente scientifica (matematica, fisica, chimica, scienze naturali) nel corso di laurea in scienze della formazione ha posto negli ultimi anni una sfida culturale alla comunità scientifica in Italia, ovvero la progettazione e l’implementazione di corsi di matematica e scienze e dei relativi aspetti didattici, rivolti a formare i futuri insegnanti della scuola primaria e della scuola dell’infanzia. La letteratura disponibile in ambito internazionale è scarsa per quanto riguarda gli insegnanti che lavorano in questo livello primario, eppure il primo incontro dei bambini con il mondo delle scienze potrebbe avere un ruolo determinante nell’emergere delle vocazioni scientifiche giovanili. Questo lavoro propone un approccio che vede la formazione umanistica declinarsi nel duplice aspetto sia letterario che scientifico: in quest’ottica, l’iniziazione al pensiero simbolico dei bambini attraverso la scolarizzazione, coinvolge gli allievi e li accompagna in un processo di maturazione che integra i diversi sguardi sul mondo (espressivo, linguistico, geometrico e quantitativo). Si descrive l’applicazione di un tale approccio al caso della chimica, attraverso alcuni esempi significativi di integrazione dei contenuti istituzionali con aspetti storici ed epistemologici; si discutono da un punto di vista qualitativo i risultati ottenuti nell’intro¬duzione di questi elementi nel corso di laurea in Scienze della Formazione Primaria dell’Università Roma Tre negli anni 2014-17. Keywords – primary education, science, chemistry, didactics, history Parole chiave – formazione primaria, scienze, chimica, didattica, storia, Annali online della Didattica e della Formazione Docente, Vol 9, N° 14 (2017): Strategie e metodologie didattiche in Matematica e nelle Scienze

In the presented work the simultaneous use of ultrasound in tracking and smart release was investigated. Hybrid microparticles based on an iron core coated by a polysaccharide were prepared and loaded with doxorubicin. The possibility to trigger and control the release of the payload was demonstrated by application of ultrasound cycles at different power and time length. Results clearly indicate a direct correlation between the intensity of the release with the two parameters. A preliminary test using Sus Domestic liver demonstrates the possibility to visualize the faith of the microparticles after injection at the target site by a linear array ultrasound transducer. The dual function of the ultrasound; to visualize the position of the microparticles and afterwards trigger the release by changing the frequency was demonstrated offering a great perspective for a future biomedical application. © 2018 TANGER Ltd. All Rights Reserved., Tomsk Polytechnic University [VIU-316/2017]