Search results for " PRIN"
showing 10 items of 1809 documents
The many faces of human sociality: uncovering the distribution and stability of social preferences
2018
There is vast heterogeneity in the human willingness to weigh others' interests in decision making. This heterogeneity concerns the motivational intricacies as well as the strength of other-regarding behaviors, and raises the question how one can parsimoniously model and characterize heterogeneity across several dimensions of social preferences while still being able to predict behavior over time and across situations. We tackle this task with an experiment and a structural model of preferences that allows us to simultaneously estimate outcome-based and reciprocity-based social preferences. We find that non-selfish preferences are the rule rather than the exception. Neither at the level of …
The application of 3d printing in plastic and reconstructive surgery: Case-control study in facial reconstruction
2017
The aim of this study was to explore the efficiency and usefulness of tridimensional printing in plastic and reconstructive surgery for lesions of the maxillofacial region. This was comparison study between two groups of patients. Six patients underwent surgical reconstruction, using a threedimensional model built on the basis of CT scans (group 1); and six patients underwent surgical reconstruction, without the use of a three-dimensional model (group 2). The following variables were evaluated: age, gender, histological diagnosis, cancer location, size of bone lesion, type of reconstruction, complications and surgical timing. A statistically significant difference was found in microsurgical…
A 3D‑scaffold of PLLA induces the morphological differentiation and migration of primary astrocytes and promotes the production of extracellular vesi…
2019
The present study analyzed the ability of primary rat astrocytes to colonize a porous scaffold, mimicking the reticular structure of the brain parenchyma extracellular matrix, as well as their ability to grow, survive and differentiate on the scaffold. Scaffolds were prepared using poly-L-lactic acid (PLLA) via thermally-induced phase separation. Firstly, the present study studied the effects of scaffold morphology on the growth of astrocytes, evaluating their capability to colonize. Specifically, two different morphologies were tested, which were obtained by changing the polymer concentration in the starting solution. The structures were characterized by scanning electron microscopy, and a…
3D cultures of primary astrocytes on Poly-L-lactic acid scaffolds
Tissue engineering is an emerging multidisciplinary field that aims at reproducing in vitro tissues with morphological and functional features similar to the biological tissue of the human body. Polymeric materials can be used in contact with biological systems in replacing destroyed tissue by transplantation [1]. Several biopolymers, including poly L (lactic acid) (PLLA), have been used in biomedical applications to set scaffolds with ductile proprieties and biodegradation kinetics [2]. In particular, the PLLA scaffold topography mimics the natural extracellular matrix and makes it a good candidate for neural tissue engineering. We report about of 3D system the PLLA porous scaffolds prepar…
3D printeru apkalpojošā personāla ķīmiskie un fizikālie darba vides riski
2018
“3D drukāšanas iekārtu apkalpojošā personāla ķīmiskie un fizikālie darba vides riski”. Darba autore: Anete Bušmane. Zinātniskā vadītāja: Dr.chem. Elīna Pajuste. Darba apjoms ir 64 lpp., tajās ietvertas 9 tabulas, 26 attēli, 1 pielikums un 42 literatūras avoti. 3D drukas nozarē no digitāla formāta tiek izdrukāts reāls un aptaustāms objekts, šī nozare līdz šim maz izpētīta ne tikai Latvijā, bet visā pasaulē. Galvenie faktori uz kuriem tiek vērsta uzmanība zinātniskajos rakstos un pētījumos, ir par nozarē sastopamajiem ķīmiskajiem un fizikālajiem riska faktoriem. Zinātnisko pētījumu šajā jomā nav daudz, un tie kas šobrīd ir pieejami nav ar viennozīmīgu informāciju, Latvijā šī nozare līdz šim n…
Green Composites Based on PLA and Agricultural or Marine Waste Prepared by FDM
2021
Three dimensional-printability of green composites is recently growing in importance and interest, especially in the view of feasibility to valorize agricultural and marine waste to attain green fillers capable of reducing bioplastic costs, without compromising their processability and performance from an environmental and mechanical standpoint. In this work, two lignocellulosic fillers, obtained from Opuntia ficus indica and Posidonia oceanica, were added to PLA and processed by FDM. Among the 3D printed biocomposites investigated, slight differences could be found in terms of PLA molecular weight and filler aspect ratio. It was shown that it is possible to replace up to 20% of bioplastic …
P3HT plānu kārtiņu īpašību pētījumi 3D printētu termoelektrisko ierīču pielietojumiem
2019
Šajā darbā tika veikti pētījumi ar poli (3-heksiltiofēna) (P3HT) plānajām kārtiņām ar mērķi novērtēt šī materiāla pielietojamību 3D printētās termoelektriskās ierīcēs. Darbā tika pētītas tīras dažādu polimerizāciju pakāpes P3HT plānās kārtiņas un kārtiņas, kas ir dopētas ar (2,3,5,6-Tetrafluoro-2,5-cikloheksadiēn-1,4-dilidēn)-dimalonodinitrilu (F4TCNQ). Šīm kārtiņām tika noteikta elektrovadītspēja, Zēbeka koeficienti kā arī jaudas faktora vērtības. Lai varētu novērtēt šo vielu pielietojamību 3D printēšanai, to veidotās plānās kārtiņas tika karsētas un noteikti to raksturojošie koeficienti pēc katras karsēšanas. Šī karsēšana simulē apstākļus, kādiem tiktu pakļauti materiāli 3D printēšanas pr…
Topoloģijas optimizācijas algoritmi 3D printējamu struktūru dizainam
2017
Darbs "Topoloģijas optimizācijas algoritmi 3D printējamu struktūru dizainam" ir veltīts topoloģijas optimizācijas algoritmu un 3D printeru funkcionalitātes izpētei. Darbā tiek apskatīti divi topoloģijas optimizācijas algoritmi un to pielietojumi vairākos piemēros. Ir veikta plaša izpēte par 3D printeru tehnisko specifikāciju, to darbību un izmantošanas veidiem. Darba galvenais mērķis ir realizēt topoloģijas optimizācijas algoritmu no uzdevuma formulējuma līdz pat gatavai, izdrukātai detaļai. Darbā ir apskatīti 3D struktūru nepieciešamie izveides nosacījumi, to modelēšana ar topoloģijas optimizāciju, kā arī pats drukāšanas process. Darba rezultātā tika iegūts dzelzceļa tilta posms, kurš vēlā…
PLLA scaffolds with controlled architecture as potential microenvironment for in vitro tumor model
2019
Abstract The "microenvironment" where a tumor develops plays a fundamental role in determining its progression, the onset of metastasis and, eventually, its resistance to therapies. Tumor cells can be considered more or less invasive depending both on the nature of the cells and on the site where they are located. Commonly adopted laboratory culture protocols for the investigation of tumor cells take usually place on standard two-dimensional supports. However, such cultures do not allow for reproduction of the biophysical properties of the tumor’s microenvironment, thus causing the cells to lose most of their relevant characteristics. In this work MDA-MB 231 breast cancer cells were cultiva…
Design challenges and opportunities of 3D printing
2019
In the future, the number and complexity of products made using additive manufacturing (AM) techniques will increase rapidly. The development of softwares and algorithms related to processes will eliminate extra intermediate steps between the product design and the end product, and will finally give us more intelligent way to manufacture these new products. More efficient 3D printing processes will enable the production of cheaper individual items and, furthermore, they will increase the demand for these high - quality tailored unrivalled solutions. The market potential is huge. However, at present the fundamentals of the area are only lightly studied and several key challenges concerning s…