Service-based dominant logic

Purpose: to investigate a concept of service-based dominant logic, define it, reveal its dimensions, theoretical framework, and managerial implications. Design/methodology/approach: the topic is approached by theoretical analysis and conceptual development. Using a definition of the dominant logic as a mind set or a world view the present article suggests ‘service-based dominant logic’ as a name for a generic theoretical concept instead of the widely used ‘service-dominant logic’ which can be easily misinterpreted as logic dominated by service only. Service-based dominant logic is ‘pure’ logic of service: it considers service as the fundamental basis of business and doesn’t include any goods-centric aspects. This logic relates to a firm’s facilitation and support of customer value creation processes using different types of resources obtained from a company. Findings: the study proposed the definition and revealed three dimensions of service-based dominant logic found in the relevant literature: ‘service logic’, ‘service-dominant logic’ and ‘customer-dominant logic’. The study showed similarities and differences between these three research streams in regard to how they defined a value, a product, a service, value creation, role of customer, role of company, and how important interactions were in value creation. The paper also described the theoretical framework of service-based dominant logic: it stated that service-based dominant logic had originated from service marketing, relationship marketing and value creation literature, and it interrelated with customer relationship management and business networks and channels research. Finally, the article classified the managerial implications of service-based dominant logic into three groups: company’s decision making, company’s organizing and company’s activities. Originality: the paper contributes conceptually to the service marketing literature by delineating the concept of service-based dominant logic. This term that before have not been widely used serves as the “umbrella” for three research streams exploring service as business perspective: ‘service logic’, ‘service-dominant logic’ and ‘customer-dominant logic’. This approach allows making deeper comparison between the main propositions of these research streams that could be interesting for the academic community for further application of research methods to collect empirical data from the corporate sector to check the findings

Quantification of the morphological characteristics of hESC colonies

The maintenance of the undifferentiated state in human embryonic stem cells (hESCs) is critical for further application in regenerative medicine, drug testing and studies of fundamental biology. Currently, the selection of the best quality cells and colonies for propagation is typically performed by eye, in terms of the displayed morphological features, such as prominent/abundant nucleoli and a colony with a tightly packed appearance and a well-defined edge. Using image analysis and computational tools, we precisely quantify these properties using phase-contrast images of hESC colonies of different sizes (0.1–1.1 mm2) during days 2, 3 and 4 after plating. Our analyses reveal noticeable differences in their structure influenced directly by the colony area A. Large colonies (A > 0.6 mm2) have cells with smaller nuclei and a short intercellular distance when compared with small colonies (A  0.6 mm2) due to the proliferation of the cells in the bulk. This increases the colony density and the number of nearest neighbours. We also detect the self-organisation of cells in the colonies where newly divided (smallest) cells cluster together in patches, separated from larger cells at the final stages of the cell cycle. This might influence directly cell-to-cell interactions and the community effects within the colonies since the segregation induced by size differences allows the interchange of neighbours as the cells proliferate and the colony grows. Our findings are relevant to efforts to determine the quality of hESC colonies and establish colony characteristics database

Seeding hESCs to achieve optimal colony clonality

Human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) have promising clinical applications which often rely on clonally-homogeneous cell populations. To achieve this, cross-contamination and merger of colonies should be avoided. This motivates us to experimentally study and quantitatively model the growth of hESC colonies. The colony population is unexpectedly found to be multi-modal. We associate these sub-populations with different numbers of founding cells, and predict their occurrence by considering the role of cell-cell interactions and cell behaviour on randomly seeded cells. We develop a multi-population stochastic exponential model for the colony population which captures our experimental observations, and apply this to calculate the timescales for colony merges and over which colony size no longer predicts the number of founding cells. These results can be used to achieve the best outcome for homogeneous colony growth from different cell seeding densities

Seeding hESCs to achieve optimal colony clonality

Human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) have promising clinical applications which often rely on clonally-homogeneous cell populations. To achieve this, it is important to ensure that each colony originates from a single founding cell and to avoid subsequent merging of colonies during their growth. Clonal homogeneity can be obtained with low seeding densities; however, this leads to low yield and viability. It is therefore important to quantitatively assess how seeding density affects clonality loss so that experimental protocols can be optimised to meet the required standards. Here we develop a quantitative framework for modelling the growth of hESC colonies from a given seeding density based on stochastic exponential growth. This allows us to identify the timescales for colony merges and over which colony size no longer predicts the number of founding cells. We demonstrate the success of our model by applying it to our own experiments of hESC colony growth; while this is based on a particular experimental set-up, the model can be applied more generally to other cell lines and experimental conditions to predict these important timescales

Correlated random walks of human embryonic stem cells in vitro

We perform a detailed analysis of the migratory motion of human embryonic stem cells in two-dimensions, both when isolated and in close proximity to another cell, recorded with time-lapse microscopic imaging. We show that isolated cells tend to perform an unusual locally anisotropic walk, moving backwards and forwards along a preferred local direction correlated over a timescale of around 50 min and aligned with the axis of the cell elongation. Increasing elongation of the cell shape is associated with increased instantaneous migration speed. We also show that two cells in close proximity tend to move in the same direction, with the average separation of m or less and the correlation length of around 25 μm, a typical cell diameter. These results can be used as a basis for the mathematical modelling of the formation of clonal hESC colonies

Quantification of the morphological characteristics of hESC colonies

The maintenance of the pluripotent state in human embryonic stem cells (hESCs) is critical for further application in regenerative medicine, drug testing and studies of fundamental biology. Currently, the selection of the best quality cells and colonies for propagation is typically performed by eye, in terms of the displayed morphological features, such as prominent/abundant nucleoli and a colony with a tightly packed appearance and a well-defined edge. Using image analysis and computational tools, we precisely quantify these properties using phase-contrast images of hESC colonies of different sizes (0.1 -- 1.1$\, \text{mm}^2$) during days 2, 3 and 4 after plating. Our analyses reveal noticeable differences in their structure influenced directly by the colony area $A$. Large colonies ($A > 0.6 \, \text{mm}^2$) have cells with smaller nuclei and a short intercellular distance when compared with small colonies ($A < 0.2 \, \text{mm}^2$). The gaps between the cells, which are present in small and medium sized colonies with $A \le 0.6 \, \text{mm}^2$, disappear in large colonies ($A > 0.6 \, \text{mm}^2$) due to the proliferation of the cells in the bulk. This increases the colony density and the number of nearest neighbours. We also detect the self-organisation of cells in the colonies where newly divided (smallest) cells cluster together in patches, separated from larger cells at the final stages of the cell cycle. This might influence directly cell-to-cell interactions and the community effects within the colonies since the segregation induced by size differences allows the interchange of neighbours as the cells proliferate and the colony grows. Our findings are relevant to efforts to determine the quality of hESC colonies and establish colony characteristics database

Drivers, types and value outcomes of customer-to-customer interaction: An integrative review and research agenda

Purpose Customer-to-customer (C2C) interaction plays a significant role in service. The purpose of this paper is to identify the drivers that motivate customers to interact with other customers, the interactions through which customers affect other customers and the value outcomes of C2C interactions for the participants.Design/methodology/approach The paper is based on a systematic literature review of C2C interactions. The authors analyzed 142 peer-reviewed articles to synthesize existing knowledge about C2C interactions. A generic value framework is used to categorize earlier research and reveal areas for further research.Findings The main outcome of this study is an integrative framework of C2C interaction that bridges C2C interactions and customer value. The findings indicate customer-, firm- and situation-induced drivers of C2C interactions. Outcome- and process-focused C2C interactions are identified to result in functional, emotional and social value outcomes. Avenues for additional research to explore issues related to current technology-saturated service settings are proposed.Research limitations/implications The paper proposes an agenda for future research to extend the C2C interaction research domain and explore how such interactions create value for the customer. The role of the service provider is not explicitly addressed but is an important area for further research.Practical implications Companies can use the framework to understand how they can become involved in and support beneficial C2C interaction.Originality/value This paper reviews empirical studies on C2C interaction, offering a systematic review of C2C interaction and producing an integrative framework of C2C interaction. It identifies a research agenda based on the framework and on topical issues within service research and practice

Митохондрии как важная мишень при поиске новых препаратов для лечения болезни Альцгеймера и старческих деменций

The review and summarizes own and literature data about the role of mitochondria as the important target in the search for drugs for the treatment of neurodegenerative diseases. Aging is a major risk factor for sporadic forms of various neurodegenerative diseases, including Alzheimer′s disease. One of the most argued and currently accepted theories is the Mitochondrial Free Radical Theory of Aging. Mitochondrial hypotheses of the development of sporadic forms of neurodegenerative diseases particularly Alzheimer′s disease, are closely connected with it. Impairments of mitochondrial functions lead to a decrease in their ability to regulate calcium homeostasis in the cell and to a decrease in the threshold for the induction of mitochondrial permeability transition (MPT) pores. MPT inhibitors can be considered as a promising approach to the treatment of neurodegenerative diseases, since these drugs can not only exhibit the properties of neuroprotectors, but also can provide normalization of synaptic activity due to increased calcium capacity of mitochondria. The review presents data on the number of MPT inhibitors, including endogenous compounds melatonin and N-acetylserotonin, their bioisosteric analogue Dimebon and a number of other compounds. The use of mitochondria as a basis for the formation of screening strategy for the search for compounds for the treatment of neurodegenerative diseases is of particular interest – both as a test of their potential toxicity, and as a basis for the creation of metabolic stimulants and drugs with neuroprotective and cognitive-stimulating effect.Обобщены собственные и литературные данные, обосновывающие роль митохондрий как важнейшей мишени при поиске препаратов для лечения нейродегенеративных заболеваний. Старение является основным фактором риска спорадических форм различных нейродегенеративных заболеваний, в том числе и болезни Альцгеймера (БА). Одной из наиболее аргументированных и принятых в настоящее время является свободнорадикальная митохондриальная теория старения. Именно с ней тесно связаны и митохондриальные гипотезы развития спорадических форм нейродегенеративных заболеваний и, в частности, БА. Нарушение митохондриальных функций приводит к снижению их способности регулировать гомеостаз кальция в клетке и снижению порога для индукции поры митохондриальной проницаемости (МРТ). Ингибиторы МРТ можно рассматривать как перспективный подход к терапии нейродегенеративных заболеваний, так как эти препараты могут не только проявлять свойства нейропротекторов, но и обеспечивать нормализацию синаптической активности благодаря увеличенной кальциевой ёмкости митохондрий. В обзоре представлены данные о ряде ингибиторов МРТ, включая эндогенные соединения – мелатонин, N-ацетилсеротонин, их биоизостерный аналог димебон и ряд других соединений. Использование митохондрий как основы для формирования скрининговой стратегии поиска соединений для лечения нейродегенеративных заболеваний представляет особый интерес и как тестирование их потенциальной токсичности, и как основа для создания метаболических стимуляторов и препаратов, обладающих нейропротекторным и когнитивно-стимулирующим действием