1,720,955 research outputs found
Optimization of liposome preparation and their pharmaceutical applicability
No full textLiposomi so majhni vezikli sferične oblike, ki so sestavljeni iz lipidov. Zaradi iste sestave kot celična stena, so biorazgradljivi. Liposomi omogočajo pasivno targetirane terapije, če pa na njihovo steno vežemo še določene ligande, pa jih lahko uporabimo za tarčno dostavo učinkovin. Zaradi njihove široke uporabnosti, je na trgu že veliko liposomalnih formulacij zdravil za različna zdravljenja, tudi proti rakavim obolenjem. Z namenom priprave nove formulacije liposomov za dostavo učinkovin, smo se odločili najprej za postavitev primernega protokola. Ker natančni protokoli za določeno formulacijo niso na voljo, smo najprej izbrali in nato optimizirali protokol priprave ustreznih liposomov, ki bi omogočal zadostno kapsulacijsko učinkovitost vodotopnih molekul. Optimizirali smo parametre nastanka lipidnega filma, temperaturo segrevanja hidracijske raztopine ter tehnik hidracije, optimizirali sestavo hidracijske raztopine in jo prilagodili biološkim pogojem, ter optimizirali dializo. Tako smo iz začetnih približno 0,1 % kapsulacijske učinkovitosti le-to povečali na 10 % za modelno spojino fluorescein. Kot modelno vodotopno učinkovino smo kapsuirali vitamin C, nato pa smo še testirali protokol za kapsulacijo lipofilne molekule digoksina. Vpliv obeh formulacij na preživetje smo preverili na rakavi liniji MDA-MD-231. Pri liposomalnem vitaminu C nam ni uspelo doseči zmanjšanja preživetja in rasti celic, pri liposomalnem digoksinu pa je bil njegov vpliv na viabilnost celic zelo močan, saj je preživelo manj kot 10 % celic.Liposomes are small spherical vesicles which are composed of lipids. Due to containing the same composition as cell walls, they are biodegradable. They can provide the opportunity for developing passively targeted therapies, and if certain ligands are bound to their wall, they are also capable of active targeting. Due to their usefulness and advantages, there are already many liposomal formulations on the market for various treatments, including cancer. With the aim of preparing the liposomes for delivering novel drugs, we have developed our own protocol to do so. Since precise protocols for a particular formulation are not available, we first chose and then optimized the protocol for the preparation of the appropriate liposomes, which would allow sufficient encapsulation efficiency of the water-soluble molecules. For the optimisation we had to vary the lipid film formation parameters, the temperature of the hydration solution and hydration techniques, optimize the composition of the hydration solution and adapt it to biological conditions and optimize the dialysis. Thus, from the initial approximately 0.1 % encapsulation, we improved the efficiency to as much as 10 % encapsulation of the model fluorescein. Vitamin C was encapsulated as a model water-soluble substance and then we tested the protocol for encapsulation of the lipophilic digoxin. The effect of both formulations on survival was verified on the MDA-MD-231 cancer line. In liposomal vitamin C, we failed to achieve an affect on cell viability and cell growth, and in liposomal digoxin its effect on cell viability was very strong, with less than 10 % of cells surviving
Positive aspects of a lesson or farm stay according to third graders
No full textV magistrskem delu smo raziskovali poznavanje in odnos učencev tretjega razreda osnovne šole do živali in dela na kmetiji, ali kmetija vpliva na boljše medsebojne odnose in delovne navade ter ali si kdo izmed učencev, ki prihajajo s kmetij, želi nadaljevati s kmetovanjem tudi v odrasli dobi.
V teoretičnem delu smo se najprej osredinili na kmetijo: kje so locirane, katere živali srečamo tam, katera dela kmetje opravljajo skozi celo leto in kako priti do dodatnega zaslužka ter kdaj pride do prevzema kmetije in zakaj so medsebojni odnosi zelo pomembni. V nadaljevanju smo se osredinili na otroke: v kolikšni meri imajo v tretjem razredu razvite psihosocialne spretnosti, kako živali vplivajo na otroke in kako preživljajo prosti čas ter kaj pomeni obisk kmetije za tretješolce.
V empiričnem delu predstavimo rezultate anketnega vprašalnika. Ugotavljali smo, ali med učenci, ki bivajo na kmetiji, učenci, ki so kmetijo obiskali v okviru pouka ali z družino, ter učenci, ki kmetije še niso obiskali, prihaja do odstopanj glede odnosa do kmetije, navezanosti na živali, znanja oziroma poznavanja kmečkih opravil, delovnih navad, druženja z družinskimi člani in ali so učenci s kmetij pripravljeni nekoč prevzeti kmetijo.This master\u27s thesis examines the knowledge and attitudes of third-grade primary school pupils toward animals and farm work. The study explores whether exposure to farm environments promotes improved relationships and work habits and investigates if pupils from farming backgrounds have any interest in continuing into adulthood.
In the theoretical section, attention is given to farms, including their locations, the animals typically found on them, the responsibilities of farmers throughout the year, strategies for earning additional income, the timing and process of taking over a farm, and the importance of interpersonal relationships in farming contexts. The psychosocial development of third-grade pupils is then addressed, focusing on how interactions with animals influence children, how children spend their leisure time, and how visiting farms impacts children of this age group.
The empirical section presents findings gained from a questionnaire. Differences were analyzed between pupils who live on farms, those who have visited farms either through school activities or with their families, and those who have never visited a farm. These groups were compared in terms of their attitudes toward farming, attachment to animals, understanding of farm tasks, work habits, interactions with family members, and willingness to take over a farm in the future
Biosynthesis, development and use od anthracycline anticancer substances in medicine
Get PDFAntraciklini so obsežna skupina protirakastih učinkovin, katerim je skupno osnovno tetraciklinsko okostje. Prva derivata antraciklinov, doksorubicin in daunorubicin, sta bila izolirana iz kulture bakterije Streptomyces peucetius že v zgodnjih šestdesetih letih prejšnjega stoletja. Učinkovine iz skupine antraciklinov proizvaja mnogo bakterij rodu Streptomyces, med katerim kot glavni proizvodni organizem antraciklinov ostaja S. peucetius. Antraciklini se uporabljajo za zdravljenje različnih oblik raka, kot so rak pljuč, prostate, različne vrste levkemije, osteogeni kostni tumor in Hodgkinov limfom. Najpogosteje pa za zdravljenje raka dojk in akutne mieloidne levkemije. Vendar pa je njihova uporaba v klinični praksi omejena zaradi močnih stranskih učinkov, kot je kardiotoksičnost, ki se kaže kot subklinično zmanjševanje funkcije levega srčnega prekata ali očitne kardiomiopatije. Glavni mehanizmi delovanja antraciklinov so reverzibilna interkalacija v DNA, nastanek prostih radikalov, vezava in alkilacija DNA, zamreženje DNA, razvijanje ali separacija verig DNA, direkten vpliv na membrano ter indukcija apoptoze. Od mnogih načinov delovanja antraciklinov sta primarni molekularni tarči delovanja DNA topoizomeraza ter reverzibilna interkalacija v DNA. Z namenom zmanjševanja stranskih učinkov in povečanja biološke aktivnosti antraciklinov se tem molekulam pogosto s postopki polsintezne kemije dodaja fluor ali dušikove spojine, pogosta pa je tudi zamenjava sladkornega ostanka na osnovnem tetraciklinskem skeletu. Poleg tega potekajo tudi raziskave novih načinov aplikacije teh potentnih učinkovin, kot so npr. priprava konjugatov s protitelesi, ter odkrivanje novih analogov antraciklina.Anthracyclines are a large group of anticancer compounds whose common characteristic is a basic tetracyclic skeleton. The first derivatives of antracycline, doxorubicin and daunorubicin, were isolated from the culture of Streptomyces peucetius in the early 1960s. The main producer of anthracyclines remains S. peucetius, but these natural products can be produced by a broad spectrum of Streptomyces species. Anthracyclines are used to treat various forms of cancer, such as lung cancer, prostate cancer, various types of leukaemia, osteogenic bone tumours and Hodgkin\u27s lymphoma, but are most commonly used to treat breast cancer and acute myeloid leukaemia. However, their use in clinical practice is limited due to the adverse side effects, such as cardiotoxicity. Cardiotoxicity is manifested as subclinical reduction of the functions of the left heart ventricle or obvious cardiomyopathy. The main mechanisms of action of anthracyclines are reversible intercalation into DNA, formation of free radicals, binding and alkylation of DNA, DNA cross-linking, separation of DNA chains, direct effect on the membrane and induction of apoptosis. The primary molecular targets of anthracyclines are DNA topoisomerases and reversible intercalation into DNA. In order to reduce the side effects and increase the biological activity of the anthracyclines, fluorine or nitrogen atoms are often added to the basic tetracycline sceleton and. the sugar moiety can also be modified. In addition, antracycline have been studied, for different applications and a lot of efforts are directed towards screening of novel anthracycline analogues
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
