The effect of starch-based biomaterials on leukocyte adhesion and activation in vitro

Leukocyte adhesion to biomaterials has long been recognised as a key element to determine their inflammatory potential. Results regarding leukocyte adhesion and activation are contradictory in some aspects of the material’s effect in determining these events. It is clear that together with the wettability or hydrophilicity/hydrophobicity, the roughness of a substrate has a major effect on leukocyte adhesion. Both the chemical and physical properties of a material influence the adsorbed proteins layer which in turn determines the adhesion of cells. In this work polymorphonuclear (PMN) cells and a mixed population of monocytes/macrophages and lymphocytes (mononuclear cells) were cultured separately with a range of starch-based materials and composites with hydroxyapatite (HA). A combination of both reflected light microscopy and scanning electron microscopy (SEM) was used in order to study the leukocyte morphology. The quantification of the enzyme lactate dehydrogenase (LDH) was used to determine the number of viable cells adhered to the polymers. Cell adhesion and activation was characterised by immunocytochemistry based on the expression of several adhesion molecules, crucial in the progress of an inflammatory response. This work supports previous in vitro studies with PMN and monocytes/macrophages, which demonstrated that there are several properties of the materials that can influence and determine their biological response. From our study, monocytes/macrophages and lymphocytes adhere in similar amounts to more hydrophobic (SPCL) and to moderately hydrophilic (SEVA-C) surfaces and do not preferentially adhere to rougher substrates (SCA). Contrarily, more hydrophilic surfaces (SCA) induced higher PMN adhesion and lower activation. In addition, the hydroxyapatite reinforcement induces changes in cell behaviour for some materials but not for others. The observed response to starch-based biodegradable polymers was not significantly different from the control materials. Thus, the results reported herein indicate the low potential of the starch-based biodegradable polymers to induce inflammation especially the HA reinforced composite materials

The immunopathology of ANCA-associated vasculitis.

The small-vessel vasculitides are a group of disorders characterised by variable patterns of small blood vessel inflammation producing a markedly heterogeneous clinical phenotype. While any vessel in any organ may be involved, distinct but often overlapping sets of clinical features have allowed the description of three subtypes associated with the presence of circulating anti-neutrophil cytoplasmic antibodies (ANCA), namely granulomatosis with polyangiitis (GPA, formerly known as Wegener's Granulomatosis), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (eGPA, formerly known as Churg-Strauss syndrome). Together, these conditions are called the ANCA-associated vasculitidies (AAV). Both formal nomenclature and classification criteria for the syndromes have changed repeatedly since their description over 100 years ago and may conceivably do so again following recent reports showing distinct genetic associations of patients with detectable ANCA of distinct specificities. ANCA are not only useful in classifying the syndromes but substantial evidence implicates them in driving disease pathogenesis although the mechanism by which they develop and tolerance is broken remains controversial. Advances in our understanding of the pathogenesis of the syndromes have been accompanied by some progress in treatment, although much remains to be done to improve the chronic morbidity associated with the immunosuppression required for disease control

Інноваційні бізнес-моделі шерінгової економіки в туризмі: на прикладі компанії Airbnb у Празі

Статтю присвячено аналізу та систематизації наукового доробку щодо розвитку туристичної галузі з урахуванням взаємозв’язку між середньою вартістю оренди апартаментів та кількістю клієнтів на платформі шерінгової економіки. Основною метою статті є оцінка взаємозалежності між попитом на нерухомість, середньою вартістю та кількістю клієнтів. Результати аналізу та систематизація наукових джерел з означеної проблематики дають підстави зробити висновок, що стрімкий розвиток Airbnb впливає на ринок готельних послуг. При цьому авторами визначено, що галузь шерінгової економіки починає суттєво змінювати ринок короткострокової оренди житла та привертає увагу регулюючих органів та бізнес-сектору. Окрім цього, розвиток онлайн-платформ шеренгової економіки (таких як Airbnb) провокують зростання пропозиції на ринку житла, а отже й рівня конкуренції на ринку туристичних послуг. У рамках даного дослідження авторами оцінено структуру та проведено сегментацію діяльності Airbnb, представлено описові статистичні дані діяльності Airbnb у місті Прага. Підґрунтям дослідження стали результати даних моніторингу 13918 запропонованих об’єктів нерухомості (заявки яких розміщено на Airbnb) у квітні 2016 року. У статті перевірку гіпотези здійснено з використанням кореляційного аналізу та аналізу змінних величин. Таким чином, отримані результати дослідження емпірично підтвердили наявність негативного лінійного взаємозв’язку між середньою вартістю оренди номеру та рівнем заселення апартаментів. На основі аналізу відхилень авторами виявлено відмінності у рівні заселення залежно від типу нерухомості. Крім цього, авторами наголошено, що отримані результати дослідження можуть бути корисними для широкого кола представників туристичної та готельної галузей, а саме: підприємців, менеджменту готелей та іних орендодавців, а також користувачів послуг проживання.This paper sums up one of issues in tourism industry within scientific framework by analysing the relationship between average daily rate and occupation rate of rentals in a sharing economy platform. The main aim of the current research is to verify the existence of a dependency between the property type and the occupancy rate, and, identify if the specific property type is more demanded on the market and confirm or reject an existence of the dependency between an average daily rate and the occupancy rate. Systematization of literary sources and approaches show that the evolution of Airbnb affects the hotel market by offering the property owners a possibility to easily share their accommodation with the visitors for a fee. The relevance of the decision of this scientific problem is that while the scale of the offered accommodation possibilities grows, the segment of the sharing economy starts to significantly change the accommodation market and attracts the attention of regulatory authorities and entrepreneurs. In this paper, the researchers discuss the structure and the segmentation of the Airbnb activities in Prague and present some descriptive statistics on Airbnb activities in this city. The research is based on the data set monitoring 13918 units in Prague offering accommodation in April 2016. Analyses of variance and correlation analysis were performed by the authors to verify scientific hypotheses. The research empirically proves that there is a negative linear relationship between the Average Daily Rate and Occupation Rate. Based on the analysis of variance, it can be stated that there are differences in occupation rate by property type. Entrepreneurs, hotels and other accommodation providers in tourism and hotel industries and visitors of accommodation services can gain benefits from the findings of this study

Sustainable value creation in event ecosystems – a business models perspective

This conceptual paper aims at characterising event sustainability from a long-term multi-stakeholder perspective, moving beyond the concept of Triple Bottom Line and event greening. Starting from the premise that sustainability should be understood critically in the wider context of society rather than from a conventional event management lens, the paper focuses on how stakeholders create sustainable value for themselves and for society beyond a specific event. Events should be considered as platforms for value creating systems and, as such, they are enabling actors (individuals and organisations) to share and integrate resources in their own social systems. The adoption of a systemic perspective grounded in Service Dominant Logic allows the authors to conceptualise sustainability as Sustainable Value Creation. Constructs derived from Business Models literature are utilised to analyse the key components of Sustainable Value Creation because they offer insights on the complex process of the creation and sharing of sustainable value focusing specifically on the stakeholders’ activities, relationships and resource exchanges