29 research outputs found
Development of breast lesions models database
No full textWe present the development and the current state of the MaXIMA Breast Lesions Models Database, which is intended to provide researchers with both segmented and mathematical computer-based breast lesion models with realistic shape
Em Algorithm for MLE of a Probit Model for Multiple Ordinal Outcomes
Full text linkThe correlated probit model is frequently used for multiple ordered data since it allows to incorporate seamlessly different correlation structures. The estimation of the probit model parameters based on direct maximization of the limited information maximum likelihood is a numerically intensive procedure. We propose an extension of the EM algorithm for obtaining maximum likelihood estimates for a correlated probit model for multiple ordinal outcomes. The algorithm is implemented in the free software environment for statistical computing and graphics R. We present two simulation studies to examine the performance of the developed algorithm. We apply the model to data on 121 women with cervical or endometrial cancer. Patients developed normal tissue reactions as a result of post-operative external beam pelvic radiotherapy. In this work we focused on modeling the effects of a genetic factor on early skin and early urogenital tissue reactions and on assessing the strength of association between the two types of reactions. We established that there was an association between skin reactions and polymorphism XRCC3 codon 241 (C>T) (rs861539) and that skin and urogenital reactions were positively correlated.
ACM Computing Classification System (1998): G.3
Investigating micronucleus assay applicability for prediction of normal tissue intrinsic radiosensitivity in gynecological cancer patients
No full textAbstractBackgroundPelvic organs morbidity after irradiation of cancer patients remains a major problem although new technologies have been developed and implemented. A relatively simple and suitable method for routine clinical practice is needed for preliminary assessment of normal tissue intrinsic radiosensitivity. The micronucleus test (MNT) determines the frequency of the radiation induced micronuclei (MN) in peripheral blood lymphocytes, which could serve as an indicator of intrinsic cell radiosensitivity.AimTo investigate a possible use of the micronucleus test (MNT) for acute radiation morbidity prediction in gynecological cancer patients.Materials and methodsForty gynecological cancer patients received 50Gy conventional external pelvic irradiation after radical surgery. A four-field “box” technique was applied with 2D planning. The control group included 10 healthy females.Acute normal tissue reactions were graded according to NCI CTCAE v.3.0. From all reaction scores, the highest score named “summarized clinical radiosensitivity” was selected for a statistical analysis.MNT was performed before and after in vitro irradiation with 1.5Gy. The mean radiation induced frequency of micronuclei per 1000 binucleated cells (MN/1000) and lymphocytes containing micronuclei per 1000 binucleated cells (cells with MN/1000) were evaluated for both patients and controls.An arbitrary cut off value was created to pick up a radiosensitive individual: the mean value of spontaneous frequency of cells with MN/1000±2SD, found in the control group.ResultsBoth mean spontaneous frequency of cells with MN/1000 and MN/1000 were registered to be significantly higher in cancer patients compared to the control group (t=2.46, p=0.02 and t=2.51, p=0.02). No statistical difference was registered when comparing radiation induced MN frequencies between those groups.Eighty percent (32) of patients developed grade 2 summarized clinical radiosensitivity, with great variations in MNT parameters. Only three patients with grade 2 “summarized clinical radiosensitivity” had values of cells with MN/1000 above the chosen radiosensitivity threshold.ConclusionThe present study was not able to confirm in vitro MNT applicability for radiosensitivity prediction in pelvic irradiation
Correction: Golkocheva-Markova, E. Editorial: Epidemiology and Control of Hepatitis Viruses. Life 2024, 14, 1369
No full textAuthor to be removed [...
The Scientific Research on motivation for learning as an important element of social and economic sciences in the context of sphere of security and defense
Full text linkThis article gives a brief overview of a study conducted on motivation for learning as an important element of social and economic sciences in the context of the sphere of security and defense. The research is an important scientific work of the author and was developed in the period 2012-2018. At present, its results have been approved, considered appropriate and acceptable, and are applied at the National Military University in Bulgaria.
The Meaning of Lead Users Within the Context of Online Platforms in the Creative Industry
Full text linkPurpose
In today’s dynamic and rapidly evolving technologically advanced world, user innovation and open source sharing are becoming powerful phenomena, which can potentially change existing business models. In this paper we integrate multi-method research, focusing on a particular segment of innovating users defined as “lead users” by von Hippel (1986) to explore their meaning within the context of the previously non-researched creative industry, represented by 3D printing and design in one particular research setting. “Lead Users” are defined by academic research as having high incentives to innovate and being at the leading edge of an important market trend. Therefore, by distinguishing between different categories of lead users in the context of our chosen research setting, we aim to define their meaning in relation to the creative industry.
Methods
The study selected a particular research setting in order to obtain primary and secondary data. Primary data in the form of ten semi-structured qualitative interviews, based on a case study approach, was used to develop and further our knowledge on the meaning of lead users within the online creative community of Thingiverse; primary data was further obtained via quantitative techniques. Secondary data was obtained through observations from blogs, online documents, and articles from independent resources.
Findings
We find that they contribute to it by determining a unique model of innovation driven by intrinsic, extrinsic and mixed incentives, which, in turn, contribute to the types of resources the lead users add to the research setting. Analyzing evidence from our research findings, we gain insights, which we believe contribute to and enrich the existing academic literature, specifically
in relation to user entrepreneurship and sources of innovation, as well as evidence for the successful coexistence of mixed resources and mixed incentives. We find that the latter is enabled by a certain group of lead users, which have managed to successfully bridge the two polar worlds.
Value and Originality
To the knowledge of the author existing academic research has not explored the creative industry and its lead users so far, therefore, this paper will add novice aspects through its findings
The Meaning of Lead Users Within the Context of Online Platforms in the Creative Industry
No full textPurpose
In today’s dynamic and rapidly evolving technologically advanced world, user innovation and open source sharing are becoming powerful phenomena, which can potentially change existing business models. In this paper we integrate multi-method research, focusing on a particular segment of innovating users defined as “lead users” by von Hippel (1986) to explore their meaning within the context of the previously non-researched creative industry, represented by 3D printing and design in one particular research setting. “Lead Users” are defined by academic research as having high incentives to innovate and being at the leading edge of an important market trend. Therefore, by distinguishing between different categories of lead users in the context of our chosen research setting, we aim to define their meaning in relation to the creative industry.
Methods
The study selected a particular research setting in order to obtain primary and secondary data. Primary data in the form of ten semi-structured qualitative interviews, based on a case study approach, was used to develop and further our knowledge on the meaning of lead users within the online creative community of Thingiverse; primary data was further obtained via quantitative techniques. Secondary data was obtained through observations from blogs, online documents, and articles from independent resources.
Findings
We find that they contribute to it by determining a unique model of innovation driven by intrinsic, extrinsic and mixed incentives, which, in turn, contribute to the types of resources the lead users add to the research setting. Analyzing evidence from our research findings, we gain insights, which we believe contribute to and enrich the existing academic literature, specifically
in relation to user entrepreneurship and sources of innovation, as well as evidence for the successful coexistence of mixed resources and mixed incentives. We find that the latter is enabled by a certain group of lead users, which have managed to successfully bridge the two polar worlds.
Value and Originality
To the knowledge of the author existing academic research has not explored the creative industry and its lead users so far, therefore, this paper will add novice aspects through its findings
Diagnostic Modalities in Colorectal Cancer –Endoscopy, Ct and Pet Scanning, Magnetic Resonance Imaging (Mri), Endoluminal Ultrasound and Intraoperative Ultrasound
No full textPatient breast MRI images and computational breast phantom data for research in patient-derived realistic breast modelling
No full textThe data is comprised of two parts: 1) patient DICOM MRI images and 2) 3D matrix of a computational breast phantom.
The DICOM images are anonymised patient breast MRI images of a female patient diagnosed with invasive ductal carcinoma. The obtaining of the patients’ DICOM images is approved by the Ethics Committee of Medical University of Varna. The acquisition was performed with GE Signa HDxt MRI scanner. The images are from a T1-weigthed Axial multi-phase VIBRANT (3-phase) sequence and with voxel size of 0.7 mm x 0.7 mm x 0.8 mm. Contrast agent is present. The image set can be opened with any standard DICOM reader.
The computational breast phantom is derived from the above mentioned dataset. The phantom is in the form of a 3D matrix saved as a MATLAB data file (.mat file). Each voxel has an assigned Hounsfield Unit value depending on its classification: air = 0, adipose tissue = -152, glandular tissue = 42, tumour = 64, skin = 108. The data file can be opened with MATLAB or Octave
