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There is still a search for a standard method of therapy for high anal fistulas. The aim of this trial was a comparison between a modified two stage minimally invasive procedure, consisting of loose-seton placement with the subsequent application of platelet rich plasma with mucosal advancement flap for the treatment of high transsphincteric anal fistulas of crypto-glandular origin.The study was designed as a prospective, randomized trial including 96 patients. Curettage of fistulous tracts, and loose-seton placement was performed in those patients with active inflammation, and if the diameter of a fistulous tract exceeded 3 mm. Afterwards, the patients were randomly assigned to either the PRP group or MAF group, consisting of 49 patients, and 47 patients, respectively.There was no significant statistical difference (p = 0.152) between both investigated groups of patients regarding closure of fistulas since it was achieved in 35 (71.43%) patients from group I, compared to 27 (57.45%) patients from group II. The diameter of fistulous tracts below 4 mm exerted a significant impact (p 0.001) on the healing process after PRP application because fistulas with the narrow tracts were closed in 34 (87.18%) patients, whereas a wider fistula was healed in 1 (10%) patient.The local application of PRP in high, unbranched, and with narrow tracts trans-sphincteric anal fistulas of crypto-glandular origin, following loose-seton drainage is an effective, simple, and a safe method of therapy with a low rate of morbidity.

Patients with Crohn disease-related anal fistulas are treated with debridement of fistulous tracts and the placement of noncutting setons (NCSs). However, to reduce the high recurrence rate, there is still a need to develop more effective treatment methods.To compare NCS with vacuum-assisted closure (VAC) treatment.Medical records of 47 patients with Crohn anal fistulas were retrospectively evaluated. They were divided into two groups (I, VAC; II, NCS), consisting of 24 and 23 patients, respectively. The fistulas in the former group were applied with VAC, whereas NCSs were placed in the latter group. Fistula healing was evaluated with the Fistula Drainage Assessment classification, Perianal Disease Activity Index, and the van Assche MRI-Based Score.There was a significant difference (P = .006) between the groups; closure of all fistulas at 6 months after treatment was achieved in 18 patients (75%) from group 1, compared with 8 patients (35%) from group 2. Partial response occurred in five patients (21%) from group 1 and in five patients (22%) from group 2. Closure of fistulous tracts was visualized via MRI in nine patients (37.50%) from group 1, more than twice as many patients as from group 2.Because preliminary results of the study showed a high rate of closure after application of VAC to Crohn anal fistulas, this method might be considered a novel sphincter-saving procedure.

Textbooks have played the leading role in academic education for centuries and their form has evolved, adapting to the needs of students, teachers and technological possibilities. Advances in technology have caused educators to look for new sources of knowledge development, which students could use inside and outside the classroom. Today’s sophisticated learning tools range from virtual environments to interactive multimedia resources, which can be called e-textbooks. Different types of new educational materials that go beyond printed books are now used to support the academic curriculum, with the most interesting ones exemplified in this article to show their value in medical and life sciences education. Certain interesting attempts by Polish publishers at applying technology to support both self-paced and tutor-paced student learning in the medical profession and related areas are presented. The data was collected through a review of literature, discussions with e-learning specialists and medical students, as well as an analysis of examples of good practices. The article also discusses the results of a countrywide survey on the use of e-textbooks to enhance medical education. The research investigates the targeted academic staff’s attitudes towards the use of e-textbooks, the limitations of their implementation, and the character of e-resources currently used by Polish higher education medical institutions.

Background: Measurements of phoria at near are important elements of the optometric assessment of binocular vision. It is important to know if different methods of measuring a phoria are interchangeable. This study was designed to compare phoria measures using in-phoropter (von Graefe) and in free space methods (Howell card). Methods: The study was conducted with 70 pre-presbyopic subjects, aged 23–35 years. Both near the von Graefe and near Howell card horizontal dissociated phorias along and with gradient +1.00 D and –1.00 D phorias were measured for each technique. Results: The mean values of the near dissociated phoria, for both test conditions (von Graefe and Howell card) showed a slight deviation in the two measures with von Graefe measures being generally more exophoric. The mean value of the phoropter phoria was 1.97 ∆ base-in and in free space, the value was 0.9 ∆ base-in. The phoropter phoria with the +1.00 D gradient was 5.24 ∆ base-in, and in free space, 2.73 ∆ base-in. Measurements of the phorometric phoria with a gradient of –1.00 D gave a mean of 0.42 ∆ base-out and 0.94 ∆ base-out in free space. The near phoria measures were significantly different for the basic near measure (p = 0.01) and for the +1.00 D gradient (p = 0.000002) but not for the –1.00 D measure (p = 0.36). Conclusion: The results of the differences in the near horizontal phoria in free space and in- phoropter were significantly different for the basic measure and for the +1.00 D gradient. The findings between the two methods of testing should therefore not be treated as equivalent or convertible. Each test method should have separate means and ranges established.

Background/Aims: Hemodialysis induces an intravascular inflammatory reaction which may further deteriorate renal function. We studied changes of serum interleukin 6 (IL6) and hepatocyte growth factor (HGF) concentrations during dialysis sessions, and at 12 month intervals. The synthesis of these cytokines in arterial endothelial cells in the presence of serum obtained from dialyzed patients was studied. Changes of the inflammatory reaction during 12 months of treatment were correlated with GFR. Methods: The study was performed on a group of 30 uremic patients treated with hemodialysis. Serum samples were collected before the start of dialysis, 15 minutes, and 4 hours later, when the session was finished. Serum levels of IL6 and HGF were measured with ELISA, as was the effect of serum samples on the synthesis of these cytokines in arterial endothelial cells. Results: At baseline hemodialysis induced an increase of serum IL6 (+10%) and HGF (+164%) levels at the end of the session. After 12 months of treatment predialysis serum IL 6 level was increased as compared to the beginning of the study (+22%), but no change in serum HGF level was observed. At that time the dialysis-induced rise of serum IL6 level was stronger than at the start (+18%), but the observed effect for HGF was weaker (+116%). An inverse correlation was observed between the dialysis-induced increase of HGF level and decrease of GFR after 12 months of study. The same relation was seen for HGF synthesis in the endothelium, but opposite for IL6 synthesis in the endothelium. Conclusions: We found that a higher HGF serum level during hemodialysis treatment is associated with a slower loss of residual renal function.

Deployment of distance education (especially e-learning) at universities requires university teachers and students to have adequate ICT (Information and Communication Technologies) competencies. Schools usually provide training for their staff in operating e-learning portals and creating courses, which is the necessary minimum for conducting distance education. On the other hand, schools do not offer any courses for students to improve their competencies necessary for e-learning, as they assume that the students’ ICT competencies acquired during the three levels of schooling (elementary, lower secondary and upper secondary) are sufficient. The authors’ observations demonstrate that this assumption is not necessarily true, particularly for students at faculties related to humanities and other specializations not of technical nature, such as medicine. The article presents an overview of ICT competencies necessary for e-learning study, comparing them with competencies of a secondary school graduate. On the basis of a research project conducted at three medical universities in Poland, the authors present the level of knowledge and practical skills in the field of ICT among students who participated in e-learning or blended learning. As a result of the project, a proposal has been presented for modifying ICT education contents for students, as well as a draft course carried on the university’s LCMS (Learning Content Management System) portal to bridge the ICT competence gaps for effective distance education.

There is scientific evidence confirming the effectiveness of e-learning within resuscitation, however, there is not enough research on modern examination techniques within the scope. The ai...

The process of continuing education of paramedics is based on gaining educational credits during five-year educational periods. One of the forms of self-improvement are Internet-based educational programs. The lack of regulations concerning the organizational and technical aspects of e-learning made the authors attempt to analyze the phenomenon. The aim of the article is to present an initial analysis of the role of online educational programs in comparison with other forms of professional training of paramedics. One in three respondents has recently used one of the methods of distance learning. Despite the low awareness of the effectiveness of e-learning, almost 70% of the interviewees expressed a positive opinion about it and over 50% were willing to use such forms in the future. The respondents preferred online trainings in the asynchronous version, containing audio-visual materials and providing the possibility to obtain a certificate issued to the participant after completing the course. The demand for topics in the area of professional training included mainly the fields of Drug Therapy, electrotherapy, electrocardiogram (ECG) evaluation, medical segregation, and help in delivery in pre-hospital conditions. Modern forms of distance learning do not make it possible to acquire practical skills, yet their role in professional training of paramedics is still significant. According to the authors, online educational programs constitute an effective complement to traditional training through the performance of tasks in a mixed form, known as blended-learning.

The aim of the study was to conduct a comparative analysis of three forms of knowledge transfer online, taking into account the long-term knowledge growth rate and the satisfaction of students surv...

Aim: Under the supervision of the Department of General and Vascular Surgery of Poznan University of Medical Sciences, a questionnaire was distributed online or as a paper version to medical students (MSs) in order to better understand the attitudes towards surgery as a specialty and to determine the reasons why students do and do not choose vascular surgery as their career path. Materials and methods: The questionnaire was distributed online or as a paper version to MSs in the 3rd, 5th, and 6th year of the PUMS 6-year M.D. program. It provided the data on the year of study, grade point average (GPA), sex, age, respondent’s specialty choice, 33 questions with responses on a 1-5 Likert scale (1 was the least important reason and 5 was the most important reason), and 2 questions with socres between 0 and 4. A total of 136 Polish MSs of PUMS completed the survey. Results: For MSs who choose vascular surgery as their career path, “endovascular capabilities of vascular surgery” and “higher income possibilities than a general surgeon” were the most important reasons. The “poor availability of work in other places than the vascular surgery department of your choice, few such clinics in the region” was the most important reason not to choose vascular surgery. A role of gender was also noted - 13% of male MSs classified gender as an “important factor”, in contrast to 60% of female MSs. Conclusions: The findings of this study might help to develop better strategies to attract future trainees to surgical specialties, particularly vascular surgery, and improve work environment.

As defined by the National Institutes of Health: “Biomedical engineering integrates physical, chemical, mathematical, and computational sciences and engineering principles to study biology, medicine, behavior, and health”. Many issues in this area are closely related to fluid dynamics. This paper provides an overview of the basic concepts concerning Computational Fluid Dynamics and its applications in medicine.

Distance education undoubtedly has many advantages, such as individualization of the learning process, unified transmission of teaching materials, the opportunity to study at any place and any time, reduction of financial costs for commuting to classes or accommodation of participants, etc. Adequate working conditions on the e-learning portal must also be present, eg. well-prepared, substantive courses and good communication between the participants. Therefore, an important element in the process of conducting e-learning courses is to measure the increase of knowledge and satisfaction of participants with distance learning. It allows for fine-tuning the content of the course and for classes to be properly organized. This paper presents the results of teaching and assessment of satisfaction with e-learning courses in “Problems of multiculturalism in medicine”, “Selected issues of visual rehabilitation” and “Ophthalmology and Ophthalmic Nursing”, which were carried out experimentally at the Faculty of Health Sciences at the Medical University of Bialystok for nursing students for the 2010/2011 academic year. The study group consisted of 72 part-time students who learnt in e-learning mode and the control group of 87 students who learnt in the traditional way. The students’ opinions about the teaching process and final exam scores were analyzed based on a specially prepared survey questionnaire. Organization of e-learning classes was rated positively by 90% of students. The average result on the final exams for all distance learning subjects was at the level of 82%, while for classes taught in the traditional form it was 81%. Based on these results, we conclude that distance learning is as effective as learning according to the traditional form in medical education studies.

Various forms of e-learning are now entering both the education system at all levels and lifelong learning. Incorporating online resources and activities into a university course curriculum involves restructuring the whole teaching programme to achieve a synergistic effect. It also requires the teachers to acquire appropriate knowledge and develop new skills necessary to supervise the educational process in a new and more versatile environment. Its implementation requires the developers and tutors to demonstrate comprehensive ICT competencies necessary for handling this new education mode, particularly when developing educational materials to be uploaded to an LMS. The development of Web 2.0 technologies has enabled educators to move from instructivism towards constructivism, constructionism and connectivism, that is, towards interactive, collaborative and active learning. The areas of the staff’s special expertise include developing and using online resources and activities, learning group management, knowledge assessment, one-to-one and one-to many communication as well as support and motivation of learners to work effectively on an online course. The ideas presented in the chapter are supported by opinions and attitudes expressed by the staff from Poznan University of Medical Sciences (Poland), Gdansk University of Technology (Poland) and West College Scotland (United Kingdom) in a survey.

Enhancement of teaching using digital materials is rapidly entering the world of medical studies. Creation of a self-learning environment supported with self-tests is received well, or even enthusiastically, among students. On the other hand, there is a relatively large group of opponents among university teachers, who do not see the need for changes in teaching and testing methodology to be made. This attitude may be surfacing as a result of anxiety connected with implementing new technologies in teaching medical subjects, as well as the belief that implementing new technologies does not have an immediate effect on learning quality. The authors of this article attempt to demonstrate that a thoughtful choice of e-learning platform facilitates the process of implementing online learning and testing aids in medical faculties. The second part of the article presents initial results of studies concerning the efficiency of learning enhanced with self-tests. Our analysis details the results of exams in pathophysiology taken by students of the medical faculty at the Poznan University of Medical Sciences. After the course, an evaluation survey was completed by 195 students concerning the quality of teaching with the use of the OLAT (Online Learning and Training) e-learning portal. It showed that students had positive attitudes toward learning with the use of online materials, particularly with regard to the use of self-tests, which allowed students to check their knowledge independently in exam-like conditions. The article that follows is targeted at those teachers who are interested in implementing a self-study and electronic knowledge evaluation environment for their courses, not necessarily in medical subjects.

The necessary prerequisites for efficiently pursuing distance learning include carefully planned organization of work and resource management tools, typically found in an internet application – a distance learning portal. The portal application must meet a number of capacity and functionality requirements. Learning goals are pursued through implementation of appropriate tools available in the portal. In the article that follows, the authors attempt to analyze this aspect of medical education as utilized by blended learning and e-learning classes. The article presents a proposal for a set of tools to organize classes in an e-learning portal at a medical school. In addition, the article presents the opinions of students of the Poznan University of Medical Sciences and the Medical University of Bialystok who took part in distance education classes.

Introduction Clinical evaluation of the Crohn's anal fistulas (CF) closure is inadequate to some extent due to earlier closure of cutaneous openings compared to fistulous tracts. There is a need for a more accurate method of assessment. Aim To compare clinical signs of CF with radiological findings, before and after treatment, to follow complete closure. Material and methods It was a retrospective study of 23 patients suffering from CF admitted to a single specialist centre, who were treated with a combination of surgical and biological therapy. Fistula healing was evaluated with fistula drainage assessment classification (FDA), perianal disease activity index (PDAI), and van Assche magnetic resonance imaging score (MRI) before and 3 months after surgery and induction of the biological treatment. Results Clinical response occurred in 13 (57%) patients 3 months after induction treatment. Complete clinical response was achieved in 8 (35%) patients, whereas partial response occurred in 5 (22%) patients. Persistence of a fistula tract was visualised on MRI in 4 (50%) patients with clinical closure. Conclusions The healing process of CF should be monitored by MRI due to the discrepancy between premature closure of external openings and fistulous tracts. Prolonged biological therapy until complete healing of anal fistulas confirmed on MRI might improve the results of treatment.

Retinol binding protein 4 (RBP4) has recently been identified as an adipokine possibly involved in the development of impaired glucose metabolism. We aimed to test serum RBP4 in healthy non-obese individuals and in patients with well-characterized phenotype: obesity without confounding effects of diabetes, metabolic syndrome or dyslipidaemia. Additionally, we examined whether serum RBP4 is associated with anthropometric parameters, insulin resistance and blood lipid parameters.Twenty-eight patients with obesity and no co-morbidities and twenty-five age-matched lean controls were recruited. Anthropometric parameters, body composition, fasting blood lipid profile, RBP4, glucose and insulin were assessed and HOMA-IR was calculated.Mean concentration of RBP4 did not differ between studied groups (in obese patients was 33.93 ± 4.46 µg/ml and 32.53 ± 2.53 µg/ml in non-obese controls). RBP4 positively correlated with serum triglycerides in obese and non-obese individuals (r = 0.74, p = 0.03 and r = 0.62, p = 0.02, respectively) and did not show any significant associations with HOMA-IR, anthropometric and body composition parameters.Excessive adiposity without co-morbidities is not associated with higher levels of circulating RBP4. Serum RBP4 cannot be considered as a direct predictive marker for impaired glucose metabolism. RBP4 possibly contributes to lipid metabolism.

This article presents an overview of generally available applications for creating multimedia and interactive educational materials, such as presentations, instructional videos, self-tests and interactive repetitions. With the use of the presented tools, pilot materials were developed to support the teaching of biostatistics at a medical university. The authors conducted surveys among students of faculties of medicine in order to evaluate the materials used in terms of quality and usefulness. The article presents the analysis of the results obtained. Building Educational Materials It is every academic teacher’s daily and time-consuming duty to prepare teaching materials for their subject. In order to improve the efficiency and quality of teaching university students, we now tend to use more electronic materials that make traditional presentation of the covered issues more attractive and enriched (Karmelita et al., 2012; Mokwa-Tarnowska, 2014). The use of multimedia resources in the teaching process is natural and desirable, while preparation of such resources must be relatively simple so that each university teacher is capable of doing it by themselves. Lack of time, inability to operate specialized software (Ren-Kurc et al., 2012), and lack of belief in the influence the format of presented contents has on teaching efficiency and quality – these are the most common reasons for not preparing electronic teaching aids. Teaching materials, usually including lectures and practical classes, may include such elements as: – text resources with graphic elements (charts, diagrams, figures), ISBN 978–83–7431–428–2 ISSN 0860-150X 105 Barbara Kolodziejczak et al. – interactive materials, such as educational games, simulations, decision labyrinths, tests, quizzes, – multimedia resources: presentations, videos, animations, and sound recordings. Building such electronic resources requires university teachers to have adequate ICT competence and to choose relevant IT tools. The choice of tools largely depends on the author’s level of skill, the requirements concerning the materials themselves, e.g. their quality and contents, and available financial resources (e.g. purchase of licenses). The key issue seems to be the availability and user-friendliness of the applications. Other basic requirements for tools used in creating educational materials are (Kolodziejczak et al., 2013): – easy building and later updating of contents, – creating materials on the basis of readily available templates, – ability to merge with existing contents, to insert graphic items and multimedia, – ability to publish contents in formats consistent with applicable standards, – ability to work on (read/write) multiple file formats, – ability to merge educational content with various forms of student activity, – ability to structure knowledge while maintaining attractive form, – ability to add instructions, feedback and summaries for the learner, – no need to use programming languages while creating the aids. Despite the fact that the above set of requirements seems obvious, it does contain a certain inconsistency. Namely, on one hand we expect the applications to be simple and intuitive for the user, and on the other hand, we expect them to give the author an extensive range of advanced content building and student activity options. There are multiple tools available on the market, with more or less restrictive licenses (including freeware). Thus, finding software with specific desired functionality may be time-consuming and troublesome, particularly for beginners in the field of creating electronic educational materials.

This article shows the organization of distance learning, particularly the idea of b-learning, combining the accomplishment of classes carried on in the traditional way and via computers. The authors present learning activities related to complementary education herein. Some of these course types may be successfully adapted to an e-learning background. The models and structure of the university virtual environment for distance learning are described. These illustrate a new approach to creating a virtual space for medical and technical studies where e-learning courses are created to be used for distance education, which allows students to be taught more effectively. The projected virtual courses for different groups of students ensure individualization of students’ work, which could be a relevant element for creating the shortest path of development of professional competencies. This paper further includes a brief overview of technologies used to build interactive elements into learning mate- rials. The authors present the use of interactive elements in medical education based on examples of certain selected games and animations.

The correlations between synaptophysin (SYP) plasma levels and the brain neurotransmission activity are still not strictly identified. However, the efficiency of neurotransmission depends, inter alia, on the age, hormonal status, and coexistence of a low-grade systemic inflammation (LGSI) which is regarded as a pathogenic link with obesity and insulin resistance, atherogenesis and aging per se.The aim of this study was to investigate the associations between synaptophysin serum levels and age, LGSI indices, homocysteine and selected hormonal parameters (dehydroepiandrosterone and its sulfate, free-testosterone, SHBG) and the prevalence of metabolic syndrome (MS) in men over the age of 40.After randomization, 157 male volunteers aged 40-80 years were included in a retrospective study. MS was diagnosed according to the International Diabetes Federation criteria. For the diagnosis of late-onset hypogonadism (LOH) we adopted the criteria proposed by the European Male Aging Study (EMAS).Synaptophysin plasma concentrations in respondents decreased with age, but only between the ages of 40 to 70 years. There were no differences in SYP plasma concentrations in men suffering from MS compared to healthy subjects (p=0.845). Men suffering from MS demonstrated while higher hs-CRP (high sensitive C - reactive protein) levels than healthy (p=0.019), contrary to the α1-antichymotrypsin and transferrin. A positive monotonic correlation between synaptophysin and hs-CRP was demonstrated (r=0.235; p=0.003). No statistically significant relationships between SYP and homocysteine plasma levels were presented (r=0.047; p=0.562), although in men diagnosed with MS higher homocysteine levels compared to healthy subjects were demonstrated. No correlations between synaptophysin and free testosterone (r=-0.036; p=0.651), DHEA (r=-0.122; p=0.128) and its sulphate (r=-0.024; p=0.764) as well as SHBG (r=-0.088; p=0.288) were demonstrated.Although the correlations between synaptophysin plasma levels and age as well as strong LGSI indicator (hs-CRP) have been demonstrated, the usefulness of determining SYP serum concentration as a marker of age-related studied diseases (MS, LOH) seems to be significantly limited.

Introduction Anal fistula in Crohn's disease is frequently an intractable condition. Methods of treatment are still debated because the results of various procedures are unsatisfactory. Available studies show that results can be improved using a combination of surgical and medical methods. Most patients undergo rather palliative than radical, curative procedures such as incision and drainage of abscesses and prolonged non-cutting seton placement. Surgery is combined today with biological therapy using infliximab, a murine-human chimeric monoclonal antibody against TNF-α or adalimumab a human monoclonal anti-TNF antibody to increase the healing process and in an attempt to prevent fistula recurrence. Methods Medical records of 23 patients who were treated for anal fistulas in Crohn's disease between 2012 and 2014 were retrospectively evaluated. Results There were 10 (43%) males and 13 females. The mean age was 39 years (range 29–60 years). Median duration of CD before present treatment was 6 years (range 1–15 years). Closure of all fistulas in 6 months was achieved in eight (35%) patients, whereas reduction of at least 50% from base line in the number of draining fistulas occurred in four (17%) patients. Conclusion Palliative and combined therapy for anal fistulas in Crohn's disease with surgery and infliximab or adalimumab therapy is an effective treatment for some patients.

Distance education is entering the area of university education with increasing strength, particularly including lifelong learning. Distance education requires a well-structured organisation and resource management tools, namely an e-learning portal. Universities which are still at the beginning of the portal implementation process may encounter numerous technical and organisational issues. This article was created with a view of educational centres in which the portal is implemented with scarce financial resources by several academic employees having little experience in the field. The authors point to several key issues, such as: analysis of the school's needs in terms of distance education server resources, choice of portal in terms of technology, supported standards or functions necessary for proper course and lastly, user management. The article also mentions the often-underestimated aspect of portal management. The authors further present the capabilities of computational clouds, their deployment in the academic environment and their use in distance learning. Such a solution is extremely rare, particularly in Eastern and Central European countries.

Teaching with the blended learning method has many supporters in the academic circles, as it emphasises the key role of the teacher (mentor) in the learning process, and fits well with the idea of the life-long learning. The volatility of materials and the continuous evolution of tools and distance teaching and learning portals must involve a continuous improvement of ICT competences among people involved in teaching with this method. This article discusses selected aspects of preparing and teaching classes and evaluating students’ knowledge in teaching with the use of the blended learning method, with a special consideration of ICT competences necessary in this respect. Moreover, the authors present certain issues which are frequently less known to academic teachers but would significantly facilitate and streamline their work, such as: virtual seminars, leading project groups, distributing information via a portal, organisational consultation tools, etc.

Let A = (a ij ) and B = (b ij ) be n-by-m real matrices. Using the notion of a block P-matrix [2] we give a necessary and sufficient condition for the set r(A, B) (c(A, B), resp.) of n-by-m matrices whose rows (columns, resp.) are independent convex combinations of the rows (columns, resp.) of A and B to consist entirely of full row (column, resp.) rank matrices. This improves a result on the set r(A, B) (c(A, B), resp.) proven in [8]. Moreover, we also derive a sufficient condition for the interval of A and B, i.e., for the set i(A, B) of real n-by-m matrices (t ij a ij + (1 − t ij )b ij ) with t ij ∈ [0,1] to have the abovementioned rank property.

Let A 1 ,…, A k be complex n -by- m matrices. Using the notion of a block P -matrix, introduced recently by Elsner and the second author, a characterization of the full rank property of all convex combinations of A 1 ,…, A k is derived.