Medical applications of shape memory alloys

Shape memory alloys (SMA) are materials that have the ability to return to a former shape when subjected to an appropriate thermomechanical procedure. Pseudoelastic and shape memory effects are some of the behaviors presented by these alloys. The unique properties concerning these alloys have encouraged many investigators to look for applications of SMA in different fields of human knowledge. The purpose of this review article is to present a brief discussion of the thermomechanical behavior of SMA and to describe their most promising applications in the biomedical area. These include cardiovascular and orthopedic uses, and surgical instruments.

Atomic Force Microscopy Investigation of NI Particles Deposited on Porous Silicon

In this thesis properties and influence of modification techniques of porous silicon were studied by Atomic Force Microscope (AFM). This device permits to visualize the surface topography and to study properties of the samples on atomic scale, which was necessary for recent investigation. Samples of porous silicon were obtained by electrochemical etching. Nickel particles were deposited by two methods: electrochemical deposition and extracting from NiCl2 ethanol solution. Sample growth was conducted in Saint-Petersburg State Electrotechnical University, LETI. Kelvin probe force microscopy (KPFM) and Magnetic force microscopy (MFM) were utilized for detailed information about surface properties of the samples. Measurements showed the difference in morphology correlating with initial growth conditions. Submicron size particles were clearly visible on surfaces of the treated samples. Although their nature was not clarified due to limitations of AFM technique. It is expected that surfaces were covered by nanometer scale Ni particles, which can be verified by implication of RAMAN device.

First-principles study on electronic and structural properties of Cu(In/Ga)Se alloys for solar cells

Thin-film photovoltaic solar cells based on the Cu(In1−xGax)Se2 (CIGS) alloys have attracted more and more attention due to their large optical absorption coefficient, long term stability, low cost, and high efficiency. Modern theoretical studies of this material with first-principles calculations can provide accurate description of the electronic structure and yield results in close agreement with experimental values, but takes a large amount of calculation time. In this work, we use first-principles calculations based on the computationally affordable meta- generalized gradient approximation of the density-functional theory to investigate electronic and structural properties of the CIGS alloys. We report on the simulation of the lattice parameters and band gaps, as a function of chemical composition. The obtained results were found to be in a good agreement with the available experimental data.

Adenovirus-mediated siRNA targeting TNF-α and overexpression of bone morphogenetic protein-2 promotes early osteoblast differentiation on a cell model of Ti particle-induced inflammatory response in vitro

Wear particles are phagocytosed by macrophages and other inflammatory cells, resulting in cellular activation and release of proinflammatory factors, which cause periprosthetic osteolysis and subsequent aseptic loosening, the most common causes of total joint arthroplasty failure. During this pathological process, tumor necrosis factor-alpha (TNF-α) plays an important role in wear-particle-induced osteolysis. In this study, recombination adenovirus (Ad) vectors carrying both target genes [TNF-α small interfering RNA (TNF-α-siRNA) and bone morphogenetic protein 2 (BMP-2)] were synthesized and transfected into RAW264.7 macrophages and pro-osteoblastic MC3T3-E1 cells, respectively. The target gene BMP-2, expressed on pro-osteoblastic MC3T3-E1 cells and silenced by the TNF-α gene on cells, was treated with titanium (Ti) particles that were assessed by real-time PCR and Western blot. We showed that recombinant adenovirus (Ad-siTNFα-BMP-2) can induce osteoblast differentiation when treated with conditioned medium (CM) containing RAW264.7 macrophages challenged with a combination of Ti particles and Ad-siTNFα-BMP-2 (Ti-ad CM) assessed by alkaline phosphatase activity. The receptor activator of nuclear factor-κB ligand was downregulated in pro-osteoblastic MC3T3-E1 cells treated with Ti-ad CM in comparison with conditioned medium of RAW264.7 macrophages challenged with Ti particles (Ti CM). We suggest that Ad-siTNFα-BMP-2 induced osteoblast differentiation and inhibited osteoclastogenesis on a cell model of a Ti particle-induced inflammatory response, which may provide a novel approach for the treatment of periprosthetic osteolysis.

Dissertatio academica Davidem regem hypnopsychitis non favere, demonstrans, contra Heinium ex occasione psalm. VI. Quam, consentiente ampliss. facult. philosoph. in regio ad Auram lycaeo, suffultus praesidio viri maxime reverendi atque celeberrimi d:ni Isaaci Ross, s. s. l. l. profess. reg. & ord. fac. phil. h. t. decani maxime spectabilis pro consequendis honoribus academicis publico examini modeste submittit Arvid Favorin, Nic. fil. Satacundensis, in aud. majori die XXII. Decembr. anni MDCCLIX. h. a. m. s

Invokaatio: J.M.G.

Estudo da estabilidade do complexo ácido fítico e o íon Ni(II)

A técnica de titulação potenciométrica foi utilizada para verificar as propriedades ácida-base do ácido fítico [1,2,3,4,5,6-hexaquis(dihidrogenofosfato)-mio-inositol] e do complexo ácido fítico e Ni(II), em solução aquosa, em temperatura e força iônica constantes. Para avaliar o comportamento térmico e a complexação do ácido fítico com o íon Ni(II) foram realizadas análises de Termogravimetria (TG), Termogravimetria Derivada (DTG), Calorimetria Exploratória Diferencial (DSC) e estudos de Espectrofotometria de Infravermelho. Foram obtidas oito constantes de protonação da amostra de ácido fítico na forma de sal de dipotássio e sete constantes de estabilidade do complexo ácido fítico e Ni(II). As reações de protonação e de formação ocorrem na faixa de pH de 2,0 a 11,0. Os dados obtidos mostram que o ácido fítico encontra-se totalmente deprotonado em pH 12,0 no qual a espécie ML (um ligante para um íon metálico) encontra-se totalmente formada no mesmo valor de pH. Os resultados obtidos por TG e DSC revelaram tanto para o ácido fítico como para o complexo boa estabilidade até a temperatura próxima a 200ºC. Por TG, DTG e DSC conclui-se também que a estequiometria do complexo estudado foi de um mol de ligante para um mol de íon metálico. A Espectrofotometria de Infravermelho comprovou a estabilidade do ácido fítico e a sua interação com o íon Ni(II).

Weldability of high strength aluminium alloys

The need for reduced intrinsic weight of structures and vehicles in the transportation industry has made aluminium research of interest. Aluminium has properties that are favourable for structural engineering, including good strength-to-weight ratio, corrosion resistance and machinability. It can be easily recycled saving energy used in smelting as compared to steel. Its alloys can have ultimate tensile strength of up to 750 MPa, which is comparable to steel. Aluminium alloys are generally weldable, however welding of high strength alloys like the 7xxx series pose considerable challenges. This paper presents research on the weldability of high strength aluminium alloys, principally the 7xxx series. The weldability with various weld processes including MIG, TIG, and FSW, is discussed in addition to consideration of joint types, weld defects and recommendations for minimizing or preventing weld defects. Experimental research was carried out on 7025-T6 and AW-7020 alloys. Samples were welded, and weld cross sections utilized in weld metallurgy studies. Mechanical tests were carried out including hardness tests and tensile tests. In addition, testing was done for the presence of Al2O3 on exposed aluminium alloy. It was observed that at constant weld heat input using a pulsed MIG system, the welding speed had little or no effect on the weld hardness. However, the grain size increased as the filler wire feed rate, welding current and welding speed increased. High heat input resulted in lower hardness of the weld profile. Weld preheating was detrimental to AW- 7020 welds; however, artificial aging was beneficial. Acceptable welds were attained with pulsed MIG without the removal of the Al2O3 layer prior to welding. The Al2O3 oxide layer was found to have different compositions in different aluminium alloys. These findings contribute useful additional information to the knowledge base of aluminium welding. The application of the findings of this study in welding will help reduce weld cost and improve high strength aluminium structure productivity by removing the need for pre-weld cleaning. Better understanding of aluminium weld metallurgy equips weld engineers with information for better aluminium weld design.

VANHEMPIEN JA KEHITYSVAMMAISEN LAPSEN ÄÄNI KUNTOUTUSSUUNNITELMA JA HOJKS SISÄLLÖNANALYYSISSÄ

Tutkimuksemme päätarkoituksena on ollut tutkia perheen osallisuutta kehitysvammaisen lapsen kuntoutuksen suunnitteluun kuntoutussuunnitelman ja henkilökohtaisen opetuksen järjestämistä koskevan suunnitelman eli HOJKS:n pohjalta. Vertailimme myös HOJKS:n ja kuntoutussuunnitelman yhtäläisyyksiä ja eroavaisuuksia. Opinnäytetyö osallistuu Varsinais-Suomen erityishuoltopiirin, Kansaneläkelaitoksen, Turun yliopistollisen keskussairaalan ja Turun yliopiston yhteiseen KeLaKuVa -tutkimushankkeeseen. Aineistomme koostuu 25 kuntoutussuunnitelmasta ja 16 HOJKS:sta sekä yhdestä varhaiskasvatussuunnitelmasta. Suunnitelmia tutkittiin sisällönanalyysin avulla aineistolähtöisesti ja myöhemmässä vaiheessa teoriaohjaavasti. Perheen ääni vaikuttaa kuuluvan hyvin kuntoutusprosessin suunnitteluvaiheessa käytössämme olleen aineiston perusteella. Lapsen kuntoutukselle asetetut tavoitteet ovat yhteneväiset kuntoutussuunnitelman ja HOJKS:n välillä, mikä on lapsen edun mukaista. Toisaalta suunnitelmien välillä on myös eroja painotuksissa: HOJKS:ssa korostuvat akateemiset taidot ja kuntoutussuunnitelmassa terapiat. Tämä puoltaa tarvetta molemmille suunnitelmille.

Traité d'histoire légendaire et anecdotique, en prose et en vers, sans titre, ni nom d'auteur, rédigé, suivant ce qui est dit dans son introduction, d'après des livres analogues écrits en arabe.

Cet opuscule commence (folio 7 recto) par un résumé de la légende iranienne depuis Housheng ; vient ensuite celle des Sassanides (folio 12 verso), sous une forme encore plus sommaire ; celle de Mahomet et des khalifes (folio 16 recto), jusqu'à Mostaʿsim billah, le dernier vicaire du Prophète, qui fut mis à mort par Houlagou ; ensuite vient un chapitre, qui est donné comme le troisième de l'ouvrage (folio 26 recto), dans lequel se trouve une histoire fantaisiste du khalife Maʾmoun ; puis un chapitre donné comme le quatrième (folio 57 recto), qui expose une histoire romanesque du khalife. omayyade Valid II, fils de Yazid ; après quoi, vient un chapitre, qui serait le cinquième (folio 73 verso), dans lequel il est parlé des aventures extraordinaires qui survinrent au roi sassanide Shapour, fils d'Hormouz, à la cour de l'empereur grec, lesquelles forment une grande partie de ce recueil de légendes. On lit, à l'intérieur de l'un des plats de la reliure, le titre fantaisiste de تحفة المرتاض في التاريخ, avec cette glose que c'est une histoire des rois, contenant des anecdotes admirables et de très beaux enseignements. Manuscrit de luxe, orné d'un sarloh, enluminé en bleu et en or.