Functional PLA based (co)polymers via ROP and RAFT polymerization

In summary, this thesis presented the synthesis of end-functional PLAs by utilizing metalalkoxide formation mainly in the presence of Ca[N(SiMe3)2]2(THF)2. The effective and mild precatalyst yielded functional PLAs with high end group fidelity which enabled the combination of mechanistically distinct ROP and RAFT polymerization techniques. This was exploited for the preparation of block and comb type copolymers with (meth)acrylate based biocompatible comonomers. Preliminary biological studies of the functional PLA (co)polymers revealed promising results, which encourages further biological applications in addition to the already begun study of the PLA-cholesterol conjugates with regard to pneumonia. For example, the PLA-retinol conjugates could be further developed so that a targeted transport of active substances into hepatic stellate cells is made possible. In addition, the potent of the precatalyst urges its exploitation for the ROP of other cyclic lactones, either for homopolymerization or for the copolymerization with lactide. Future research will focus on the detailed elucidation of the proposed ROP mechanism in the presence of Ca[N(SiMe3)2]2(THF)2

Intracellularly Released Cholesterol from Polymer-Based Delivery Systems Alters Cellular Responses to Pneumolysin and Promotes Cell Survival

Cholesterol is highly abundant within all human body cells and modulates critical cellular functions related to cellular plasticity, metabolism, and survival. The cholesterol-binding toxin pneumolysin represents an essential virulence factor of Streptococcus pneumoniae in establishing pneumonia and other pneumococcal infections. Thus, cholesterol scavenging of pneumolysin is a promising strategy to reduce S. pneumoniae induced lung damage. There may also be a second cholesterol-dependent mechanism whereby pneumococcal infection and the presence of pneumolysin increase hepatic sterol biosynthesis. Here we investigated a library of polymer particles varying in size and composition that allow for the cellular delivery of cholesterol and their effects on cell survival mechanisms following pneumolysin exposure. Intracellular delivery of cholesterol by nanocarriers composed of Eudragit E100-PLGA rescued pneumolysin-induced alterations of lipid homeostasis and enhanced cell survival irrespective of neutralization of pneumolysin

Malignant melanoma of the stomach presenting in a woman: a case report

<p>Abstract</p> <p>Introduction</p> <p>Malignant melanoma is reported to metastasize to all organs of the human body. Although it is common for it to metastasize to the gastrointestinal tract, a melanoma located primarily in the gastric mucosa is an uncommon tumor. Gastrointestinal metastases are rarely diagnosed before death with radiological and endoscopic techniques.</p> <p>Case presentation</p> <p>In this case report the clinical course and treatment of a woman with melanoma of the stomach, without any other detectable primary lesion, is presented and discussed. A 55-year-old Turkish woman presented to our clinic with complaints of muscle pain and bone pain in the left side of her chest. During an upper gastrointestinal system endoscopy, dark cherry-colored, light elevated, round-shaped lesions were taken from her gastric fundus and from the first part of her duodenum. Biopsies from these samples were determined to be malignant melanoma by the pathologist.</p> <p>Conclusion</p> <p>Metastatic malignant melanoma cases should be examined through endoscopy for gastrointestinal metastases.</p

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Happiness-targeted shopping behaviors in the covid-19 pandemic

COVID-19 salgını, Mart 2020’den itibaren dünyada ve Türkiye’de yaşamın her alanında etkili olduğu gibi, günlük alışkanlıklarda ve tüketici tercihlerinde de önemli değişimlere yol açmıştır. Özellikle karantina dönemleri; internet kullanımının artmasına, online alışverişin ve kargo/kurye hizmetlerinin yaygınlaşmasına zemin hazırlamıştır. Bu çalışmada; COVID-19 salgınının ekonomik, sosyal ve psikolojik güçlükleriyle baş etmede alışveriş yapmanın, özellikle de zaruri ihtiyaç kategorisinde olmayan alışverişlerin yeri, kapsamı ve bireyler üzerindeki etkisi ele alınmıştır. COVID-19 salgınında mutluluk hedefli alışveriş davranışlarını tespit etmek amacıyla bir online anket aracılığıyla tüketicilerin görüşlerine başvurulmuştur. 482 gönüllü katılımcıdan derlenen veri seti; nicel ve nitel analiz teknikleri ile değerlendirilmiştir. Salgın döneminde satın alma davranışlarındaki değişimler, COVID-19 salgınında alışveriş kanalı tercihleri, mutluluk hedefli olarak tercih edilen ürünler ve bu alışverişlerin tüketiciler üzerindeki etkisi incelenmiş; katılımcıların demografik özellikleri ile ilişkilendirilerek analiz edilmiştir. Elde edilen veriler ışığında, COVID-19 salgınına has ürün tercihleri tespit edilmiş; salgının alışveriş kanalı tercihlerinde ve tüketicilerin satın alma davranışlarında kalıcı değişimlere yol açacağı öngörülmüştür.The COVID-19 pandemic, which has been effective in all areas of life in the world and in Turkey since March 2020, has also led to significant changes in consumer preferences and shopping habits. It is known that the quarantine periods has paved the way for the increase in internet usage and the spread of online shopping and cargo service demand. In this study, the scope of shopping, particularly shopping that is not in the category of essential needs, and its effect on individuals in coping with the economic, social and psychological difficulties of the pandemic are discussed. To determine happiness-targeted shopping behaviors, consumers’ opinions were sought through an online survey. The data set was compiled from 482 volunteer participants and analyzed with quantitative and qualitative analysis techniques. Changes in purchasing behaviors and shopping channel preferences during the pandemic is examined. Happinessoriented products preferred, shopping behaviors focused on happiness, and their effect on consumers were analyzed by associating them with the demographic characteristics of the participants. According to data obtained, product preferences specific to the pandemic were determined and it was predicted that the pandemic would lead to permanent changes in the shopping channel preferences and purchasing behaviors of consumer

Investigation of the relationship between wearing glasses and deep cervical flexor endurance in patients with non-specific neck pain

Aims: The aims of this study: 1) to determine postural changes according to wearing glasses and relationship between these changes and deep cervical flexor muscle group, 2) to investigate effectiveness of endurance training on postural changes and deep cervical flexor muscles

The Control Unit of a Single Phase Voltage Regulator

Supplying regulated voltage to critical loads is an important topic for several years. This paper presents a single-phase electronic voltage regulator based on high frequency switching of an isolated transformer where primary side voltage is controlled by two full-bridge converters sharing a common DC bus and operating at 50Hz and 20kHz switching frequencies. This allows 50Hz induced voltage on the primary side of the transformer, regulated by high frequency switching. Depending on the input voltage, voltage at the secondary side of the transformer add to (boost mode) or subtract (buck mode) from the supply voltage, therefore, maintaining a regulated voltage value across the load. The regulator is controlled by a digital controller allowing fast dynamic response. A 5kVA single-phase voltage regulator is realized to verify the operation of the proposed algorithm. The experimental results show that regulator maintains constant voltage across the load both in step-up (low supply voltage) and step-down (high supply voltage) modes