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  • Review
    Citation - WoS: 3
    Citation - Scopus: 9
    An Empirical Evaluation of Software Quality Assurance Practices and Challenges in a Developing Country: a Comparison of Nigeria and Turkey
    (Springer international Publishing Ag, 2016) Sowunmi, Olaperi Yeside; Mısra, Sanjay; Misra, Sanjay; Fernandez-Sanz, Luis; Crawford, Broderick; Soto, Ricardo; Mısra, Sanjay; Computer Engineering; Computer Engineering
    Background: The importance of quality assurance in the software development process cannot be overemphasized because its adoption results in high reliability and easy maintenance of the software system and other software products. Software quality assurance includes different activities such as quality control, quality management, quality standards, quality planning, process standardization and improvement amongst others. The aim of this work is to further investigate the software quality assurance practices of practitioners in Nigeria. While our previous work covered areas on quality planning, adherence to standardized processes and the inherent challenges, this work has been extended to include quality control, software process improvement and international quality standard organization membership. It also makes comparison based on a similar study carried out in Turkey. The goal is to generate more robust findings that can properly support decision making by the software community. The qualitative research approach, specifically, the use of questionnaire research instruments was applied to acquire data from software practitioners. Results: In addition to the previous results, it was observed that quality assurance practices are quite neglected and this can be the cause of low patronage. Moreover, software practitioners are neither aware of international standards organizations or the required process improvement techniques; as such their claimed standards are not aligned to those of accredited bodies, and are only limited to their local experience and knowledge, which makes it questionable. The comparison with Turkey also yielded similar findings, making the results typical of developing countries. The research instrument used was tested for internal consistency using the Cronbach's alpha, and it was proved reliable. Conclusion: For the software industry in developing countries to grow strong and be a viable source of external revenue, software assurance practices have to be taken seriously because its effect is evident in the final product. Moreover, quality frameworks and tools which require minimum time and cost are highly needed in these countries.
  • Book Part
    Citation - WoS: 15
    Citation - Scopus: 15
    Comparison of Hematopoietic and Spermatogonial Stem Cell Niches From the Regenerative Medicine Aspect
    (Springer international Publishing Ag, 2018) Kose, Sevil; Yersal, Nilgun; Onen, Selin; Korkusuz, Petek
    Recent advances require a dual evaluation of germ and somatic stem cell niches with a regenerative medicine perspective. For a better point of view of the niche concept, it is needed to compare the microenvironments of those niches in respect to several components. The cellular environment of spermatogonial stem cells' niche consists of Sertoli cells, Leydig cells, vascular endothelial cells, epididymal fat cells, peritubular myoid cells while hematopoietic stem cells have mesenchymal stem cells, osteoblasts, osteoclasts, megacaryocytes, macrophages, vascular endothelial cells, pericytes and adipocytes in their microenvironment. Not only those cells', but also the effect of the other factors such as hormones, growth factors, chemokines, cytokines, extracellular matrix components, biomechanical forces (like shear stress, tension or compression) and physical environmental elements such as temperature, oxygen level and pH will be clarified during the chapter. Because it is known that the microenvironment has an important role in the stem cell homeostasis and disease conditions, it is crucial to understand the details of the microenvironment and to be able to compare the niche concepts of the different types of stem cells from each other, for the regenerative interventions. Indeed, the purpose of this chapter is to point out the usage of niche engineering within the further studies in the regenerative medicine field. Decellularized, synthetic or non-synthetic scaffolds may help to mimic the stem cell niche. However, the shared or different characteristics of germ and somatic stem cell microenvironments are necessary to constitute a proper niche model. When considered from this aspect, it is possible to produce some strategies on the personalized medicine by using those artificial models of stem cell microenvironment.
  • Book Part
    Citation - WoS: 3
    Citation - Scopus: 4
    Stem Cell Applications in Lysosomal Storage Disorders: Progress and Ongoing Challenges
    (Springer international Publishing Ag, 2021) Kose, S.; Aerts-Kaya, F.; Cetinkaya, D. Uckan; Korkusuz, P.
    Lysosomal storage disorders (LSDs) are rare inborn errors of metabolism caused by defects in lysosomal function. These diseases are characterized by accumulation of completely or partially degraded substrates in the lysosomes leading to cellular dysfunction of the affected cells. Currently, enzyme replacement therapies (ERTs), treatments directed at substrate reduction (SRT), and hematopoietic stem cell (HSC) transplantation are the only treatment options for LSDs, and the effects of these treatments depend strongly on the type of LSD and the time of initiation of treatment. However, some of the LSDs still lack a durable and curative treatment. Therefore, a variety of novel treatments for LSD patients has been developed in the past few years. However, despite significant progress, the efficacy of some of these treatments remains limited because these therapies are often initiated after irreversible organ damage has occurred. Here, we provide an overview of the known effects of LSDs on stem cell function, as well as a synopsis of available stem cell-based cell and gene therapies that have been/are being developed for the treatment of LSDs. We discuss the advantages and disadvantages of use of hematopoietic stem cell (HSC), mesenchymal stem cell (MSC), and induced pluripotent stem cell (iPSC)-related (gene) therapies. An overview of current research data indicates that when stem cell and/or gene therapy applications are used in combination with existing therapies such as ERT, SRT, and chaperone therapies, promising results can be achieved, showing that these treatments may result in alleviation of existing symptoms and/or prevention of progression of the disease. All together, these studies offer some insight in LSD stem cell biology and provide a hopeful perspective for the use of stem cells. Further development and improvement of these stem cell (gene) combination therapies may greatly improve the current treatment options and outcomes of patients with a LSD.
  • Book Part
    Citation - WoS: 13
    Citation - Scopus: 14
    Neurological Regulation of the Bone Marrow Niche
    (Springer international Publishing Ag, 2020) Aerts-Kaya, Fatima; Ulum, Baris; Mammadova, Aynura; Kose, Sevil; Aydin, Gozde; Korkusuz, Petek; Uckan-Cetinkaya, Duygu
    The bone marrow (BM) hematopoietic niche is the microenvironment where in the adult hematopoietic stem and progenitor cells (HSPCs) are maintained and regulated. This regulation is tightly controlled through direct cell-cell interactions with mesenchymal stromal stem (MSCs) and reticular cells, adipocytes, osteoblasts and endothelial cells, through binding to extracellular matrix molecules and through signaling by cytokines and hematopoietic growth factors. These interactions provide a healthy environment and secure the maintenance of the HSPC pool, their proliferation, differentiation and migration. Recent studies have shown that innervation of the BM and interactions with the peripheral sympathetic neural system are important for maintenance of the hematopoietic niche, through direct interactions with HSCPs or via interactions with other cells of the HSPC microenvironment. Signaling through adrenergic receptors (ARs), opioid receptors (ORs), endocannabinoid receptors (CRs) on HSPCs and MSCs has been shown to play an important role in HSPC homeostasis and mobilization. In addition, a wide range of neuropeptides and neurotransmitters, such as Neuropeptide Y (NPY), Substance P (SP) and Tachykinins, as well as neurotrophins and neuropoietic growth factors have been shown to be involved in regulation of the hematopoietic niche. Here, a comprehensive overview is given of their role and interactions with important cells in the hematopoietic niche, including HSPCs and MSCs, and their effect on HSPC maintenance, regulation and mobilization.
  • Review
    Citation - WoS: 31
    Citation - Scopus: 43
    A Systematic Literature Review of Open Source Software Quality Assessment Models
    (Springer international Publishing Ag, 2016) Adewumi, Adewole; Misra, Sanjay; Omoregbe, Nicholas; Crawford, Broderick; Soto, Ricardo
    Background: Many open source software (OSS) quality assessment models are proposed and available in the literature. However, there is little or no adoption of these models in practice. In order to guide the formulation of newer models so they can be acceptable by practitioners, there is need for clear discrimination of the existing models based on their specific properties. Based on this, the aim of this study is to perform a systematic literature review to investigate the properties of the existing OSS quality assessment models by classifying them with respect to their quality characteristics, the methodology they use for assessment, and their domain of application so as to guide the formulation and development of newer models. Searches in IEEE Xplore, ACM, Science Direct, Springer and Google Search is performed so as to retrieve all relevant primary studies in this regard. Journal and conference papers between the year 2003 and 2015 were considered since the first known OSS quality model emerged in 2003. Results: A total of 19 OSS quality assessment model papers were selected. To select these models we have developed assessment criteria to evaluate the quality of the existing studies. Quality assessment models are classified into five categories based on the quality characteristics they possess namely: single-attribute, rounded category, community-only attribute, non-community attribute as well as the non-quality in use models. Our study reflects that software selection based on hierarchical structures is found to be the most popular selection method in the existing OSS quality assessment models. Furthermore, we found that majority (47%) of the existing models do not specify any domain of application. Conclusions: In conclusion, our study will be a valuable contribution to the community and helps the quality assessment model developers in formulating newer models and also to the practitioners (software evaluators) in selecting suitable OSS in the midst of alternatives.