Asymmetric amphiphilic triblock copolymers : synthesis, characterization and self-assembly

We developed a synthetic pathway to new amphiphilic ABC triblock copolymers with watersoluble blocks A and C and a hydrophobic middle block B. The synthesis involves a two-step polymerization. The prepolymer AB, constituted of poly(ethylene) oxide –b –poly(dimethyl) siloxane was prepared by anionic ring-opening polymerization of cyclic siloxanes, withandsiloxane units. The polymerization of strained cycles (e.g., D3) leads to polysiloxanes with monodisperse chains; the reaction time for anionic polymerization is lower and the yield of polymerization improved. Finally using the AB diblock copolymers as macroinitiators, a cationic polymerization of 2-methyloxazoline leads to asymmetric ABC triblock copolymers. As a model polymer we used an amphiphilic polyethylene oxide-b-polydimethylsiloxane-b-poly 2-methyloxazoline (PEO-b-PDMS-b-PMOXA) triblock copolymer. In aqueous solutions, this triblock copolymer self-assembles into well defined supramolecular aggregates. For certain compositions, the triblock copolymers form membrane like-superstructures and spherical vesicles in aqueous media. With the help of fluorescently labelled polymers, we were able to prove that the walls of these vesicles are asymmetric, due to the incompatibility between the hydrophilic chains: the blocks A and C are segregated on two different sides of the membrane. In case of nanometer-sized vesicles where membrane-curvature plays an important role we were even able to achieve a control over the membrane orientation, i.e., which of the two hydrophilic block is at the inner and which at the outer surface. This seems to be mainly gouverned by steric considerations: generally the smaller hydrophilic blocks are forced to the inner side where less space is available. Interestingly, the intrinsic asymmetry of the vesicular walls induced a directed insertion of transmembrane proteins. Using Aquaporinas a model system we employed immunoassay, immunofluorescence and immunogold labelling, to quantify the amount and the orientation of these proteins in the walls of the asymmetric ABC-block copolymer vesicles. The results clearly show a direct correlation between the membrane orientation and the prefered direction of the proteins. These studies indicate clearly that amphiphilic ABC triblock copolymers provide a convenient way to come to new materials with a directional functionality. Since they allow even a control over the orientation, they could allow to realize systems with a functionality that is reversed with respect to the biological model

COUNTRY-OF-ORIGIN EFFECTS ON PURCHASING DOMESTIC PRODUCTS: THE CASE OF ROMANIA

Previous studies revealed that ethnocentric consumers are more willing to purchase a domestic product. Furthermore, country-of-origin has a direct impact on consumers’ decision to buy a product in such a manner that a positive country image can substitute other missing qualities of the product. On the other hand, a strong brand is not expected to compensate for a negative country-of-origin perception. Many brands rely on their home country as a warranty for quality and prestige, in order to gain consumers’ interest and attention. This paper examines the moderating role of variables such as perceived quality, ethnocentrism and familiarity in determining a consumer to buy a domestic product. Through exploratory research, this study aims to investigate to what extent Romania, as country-of-origin for its local products, influences consumers’ decision making process. The major contributions of the study consist of identifying the elements that play a role in consumers’ product evaluation based on the country-of-origin and to improve the understanding of country image effects on the buying intention

THE IMPACT OF ORIGIN ON CREATING A CULT BRAND: THE CASE OF APPLE

This paper introduces the concept of a cult brand for a more accurate understanding of the extreme loyalty that consumers show towards specific brands. The article focuses on the brand Apple and it explores the elements for which it is considered a cult brand and the impact of its origin on sustaining its cult appeal. Based on the fact that many brands rely on emotional characteristics to obtain consumers’ interest and attention, the country responsible for their conception is usually a warranty for quality and respect, features transferred to consumers. Through an exploratory research, based on investigation of secondary information as a data collection method, the research focuses on Apple's corporate mythology, its brand name, its geographical provenance and also the community surrounding it. The results of the study revealed that brand origin had a major role in creating the image that Apple sustained in the last decades, the conclusion reinforced the idea that on a solid foundation can be built a complex structure

Extruded Nucleoli of Human Dental Pulp Cells

Background and Objectives: The dental pulp stem cells are highly proliferative and can differentiate into various cell types, including endothelial cells. We aimed to evaluate the ultrastructural characteristics of the human dental pulp cells of the permanent frontal teeth. Materials and Methods: Human adult bioptic dental pulp was collected from n = 10 healthy frontal teeth of five adult patients, prior to prosthetic treatments for aesthetic purposes. Tissues were examined under transmission electron microscopy. Results: We identified cells with a peculiar trait: giant nucleoli resembling intranuclear endoplasmic reticulum, which mimicked extrusion towards the cytoplasm. These were either partly embedded within the nuclei, the case in which their adnuclear side was coated by marginal heterochromatin and the abnuclear side was coated by a thin rim of ribosomes, or were apparently isolated from the nuclei, while still being covered by ribosomes. Conclusions: Similar electron microscopy features were previously reported in the human endometrium, as nucleolar channel system; or R-Rings induced by Nopp140. To our knowledge, this is the first report of extruded nucleolar structure in the dental pulp. Moreover, the aspect of giant extruded nucleoli was not previously reported in any human cell type, although similar evidence was gathered in other species as well as in plants

SPECTRUL EPIDEMIOLOGIC, CLINIC ŞI EVOLUTIV AL CAZURILOR DE RUJEOLĂ INTERNATE ÎN SPITALUL CLINIC DE BOLI INFECŢIOASE ŞI TROPICALE „DR. VICTOR BABEŞ“ DIN BUCUREŞTI ÎN CURSUL EPIDEMIEI ACTUALE

Introducere. Începând cu anul 2016, România se confruntă cu o epidemie importantă de rujeolă apărută pe fondul unui procent tot mai scăzut de vaccinare. Evoluţia epidemiei a fost marcată şi de o creştere alarmantă a numărului de complicaţii şi decese. Materiale şi metode. Am evaluat retrospectiv 632 pacienţi diagnosticaţi cu rujeolă, internaţi în Spitalul Clinic de Boli Infecţioase şi Tropicale „Dr. Victor Babeş“, în perioada ianuarie 2016 – decembrie 2017. Datele epidemiologice, caracteristicile clinice şi rezultatele probelor biologice au fost obţinute din fişele medicale ale pacienţilor. Rezultate. Din cei 632 de pacienţi, 341 (53,9%) au fost de sex masculin. Grupa de vârstă cea mai afectată a fost 1-4 ani (39,2%), urmată de cea a sugarilor cu un procent de 19,6%. O treime din cazuri (31,3%) au avut contactul infectant în cadrul familiei. În ceea ce priveşte statusul vaccinal, aproape jumătate din pacienţi (47,1%) nu au fost vaccinaţi, iar 44,3% nu cunoşteau istoricul de vaccinare (probabil nevaccinaţi sau incomplet vaccinaţi). Complicaţiile virale au fost prezente la majoritatea pacienţilor (84,1%) sub forma unei pneumonii interstiţiale. Pneumonia bacteriană a fost prezentă la 15% dintre pacienţi, iar dintre aceştia 45,2% au asociat şi insuficienţă respiratorie. Şase pacienţi au necesitat transfer în secţia de terapie intensivă pediatrie pentru suport respirator, înregistrându-se 2 decese. Laringita a fost prezentă în 8,2% cazuri, otita în 12% cazuri, în timp ce 61,7% dintre pacienţi au avut afectare gastrointestinală. Paraclinic, a fost evidenţiată citoliza hepatică la 101 (15,9%) pacienţi şi diselectrolitemia a fost prezentă la 94 (14,8%) din cazuri. Concluzii. Studiul prezent arată creşterea alarmantă a incidenţei bolii şi a complicaţiilor sale în ultimii 3 ani, mai ales la vârstele mici. Considerăm imperios necesară aplicarea programului de vaccinare pentru a asigura o acoperire vaccinală optimă, utilă atât în stoparea epidemiei actuale, cât şi în prevenirea unor viitoare epidemii

EPIDEMIOLOGICAL, CLINICAL AND PROGRESSIVE SPECTRUM OF MEASLES CASES ADMITTED TO „DR. VICTOR BABES“ CLINICAL HOSPITAL FOR INFECTIOUS AND TROPICAL DISEASES, BUCHAREST DURING THE ACTUAL OUTBREAK

Introduction. Starting with 2016 Romania had to face an alarming measles outbreak due to the continuous poor vaccination coverage. The outbreak associated an increased number of complications and deaths. Materials and methods. We performed a retrospective study, on a group of patients with measles, admitted to „Dr. Victor Babes“ Hospital. Epidemiological data, clinical characteristics and the results of the biological samples were obtained from the patient's medical records between January 2016 and December 2017. Results. Out of the 632 patients, 341 (53.9%) were males. Most of them (39.2%) were children, between 1 and 4 year-old, while 19.6% were infants. A quarter of the patients (31.3%) had familial contact with a measles case. The vaccination history was unknown in 44.3% cases; almost half of the patients (47.1%) were unvaccinated. Almost all of them developed viral complications, 84.1% being diagnosed with interstitial pneumonia. Bacterial pneumonia was diagnosed in 15.0% cases, out of which 45.2% were also associated with respiratory failure. Six patients required transfer to the pediatric intensive care unit for respiratory support and 2 died. Other complications were: laryngitis 8.2%, otitis 12.0% of the cases. Also 61.77% of the patients were diagnosed with enterocolitis. There was no case complicated with encephalitis. 101 (15.9%) patients developed liver cytolysis, while dyselectrolytemia was present in 94 (14.8%) cases. Conclusions. The number of patients diagnosed with measles during the last years registered an alarming increase, especially in children under 4 year old, with a high number of complications. We consider it mandatory to apply the vaccination program to ensure an optimal vaccine coverage, useful both in stopping the current outbreak and in preventing future outbreaks