Frog skin active peptides (FSAP) as a highy effective antimicrobial agents

During last ten to fifteen years a considerable scientific attention has been paid to biologically active substances as known as frog skin active peptides (FSAP). These substances are naturally produced by many Amphibian organisms and could be found within skin secretion of most frog families, especially Ranidae. Biomolecules of that class possess extremely valuable properties: show high antimicrobial and antifungal activity - especially effective against multiresistant bacterial infections; act as protease inhibitors and components of an innate immune system; demonstrate relatively weak hemolytic activity. Such a combination makes frog skin active peptides a potential candi dates for drug development with possible application in therapy, traumatology, surgery, etc. In present paper an origin, classification, function as well as methods for determination of FSAP are summarized. It is underlined that Bulgarian region is definitely suitable for extensive FSAP investigations due to the naturally abundance of genus Rana species.Scripta Scientifica Medica 2009; 41(2): 195-200

The use of virtual machines in education institutions

The possibility of virtual machines are wide enough. They address many issues related to application compatibility and operating system, as well as the safe use of a personal computer, which in turn is important for educational institutions due to the rapid pace of development of information technologiesВозможности виртуальных машин достаточно широки. Они решают многие вопросы, связанные с совместимостью приложений и операционной системы, а так же с безопасным использованием персонального компьютера, что, в свою очередь, важно для образовательных учреждений в силу быстрых темпов развития информационных технологи

Didactic principles on the basis of use of virtual machines

This article describes the generally recognized didactic principles, considered the idea of the use of virtual machines in the educational process, as well as didactic principles underlying the use of virtual machinesВ данной статье рассмотрены общепризнанные дидактические принципы, рассмотрена идея о применении виртуальных машин в образовательном процессе, а также дидактические принципы, положенные в основу использования виртуальных маши

Bone remodeling markers after experimental augmentation of trabecular bone defects with resorbable and non-resorbable osteoplastic materials in rabbits

To study the effect of bone defect augmentation on the dynamics of bone remodeling markers. Material and methods The effect of resorbable xenoplastic material (RXM), synthetic beta-tricalcium phosphate (b-TCP), porous titanium implant (PTI) and nanostructured carbon implant (NCI) on the markers of bone remodeling (osteocalcin, OC; bone alkaline phosphatase, BALP; C-terminal telopeptide of type I collagen, CTX-1) and inflammation marker (C-reactive protein, CRP) was investigated using bone defect model in rabbits. 24 animals were divided into 4 groups (n = 6 in each group) according to the type of osteoplastic material. Control group (n = 6) was without augmentation. An impression fracture of the proximal tibia was modeled. Blood samples were taken on days 1, 3, 7, 14, 45, 90, 180 after surgery. Results CTX-1was not detected in the control, b-TCP, PTI, and RXM groups after 90 days, but in the NCI group CTX-1 remained elevated until the end of the study. OC in the control, b-TCP, PTI groups reached a maximum at 14-45 days. No significant increase in OC was found in the NCI group. The BALP in the control group peaked at 90 days. In the b-TCP and PTI groups the concentration of BALP increased more rapidly. The dynamics of CRP in the RXM, b-TCP and PTI groups was similar to the dynamics in the control group, in the NCI group an increased level of CRP remained until the end of the study. Conclusion When a bone defect was augmented with both resorbable b-TCP and nonresorbable PTI, high osteogenesis activity and low osteoresorption activity were detected. The use of xenoplastic material did not reveal any advantages in comparison with surgery performed without augmentation. An increase in osteoresorption and a low level of osteogenesis were found by using NCI. © Yildiz K., Yildiz V., 2020

Imitation model of the electric trolley overhead crane

The article focuses on the analysis of the interaction between electric trolley and the cargo of the overhead crane. The influence of static and dynamic forces on the movement of the trolley and the cargo is examined, the reasons for the free fluctuations of the cargo are investigated. A computer model for studying the interaction of the cargo and the electric drive of the trolley is presented.В статье основное внимание уделяется анализу взаимодействия электропривода тележки и груза мостового крана. Рассматривается влияние статических и динамических сил на движение тележки и груза, исследуются причины свободных колебаний груза. Представлена компьютерная модель для изучения взаимодействия груза и электропривода тележки

Sentinel headache as a warning symptom of ischemic stroke

Background: There are no previous controlled studies of sentinel headache in ischemic stroke. The purpose of the present study was to evaluate the presence of such headache, its characteristics and possible risk factors as compared to a simultaneous control group. Methods: Eligible patients (n = 550) had first-ever acute ischemic stroke with presence of new infarction on magnetic resonance imaging with diffusion-weighted imaging (n = 469) or on computed tomography (n = 81). As a control group we studied in parallel patients (n = 192) who were admitted to the emergency room without acute neurological deficits or serious neurological or somatic disorders. Consecutive patients with stroke and a simultaneous control group were extensively interviewed soon after admission using validated neurologist conducted semi-structured interview forms. Based on our previous study of sentinel headache in transient ischemic attacks we defined sentinel headache as a new type of headache or a previous kind of headache with altered characteristics (severe intensity, increased frequency, absence of effect of drugs) within seven days before stroke. Results: Among 550 patients with stroke 94 patients (17.1%) had headache during seven days before stroke and 12 (6.2%) controls (p < 0.001; OR 3.9; 95% CI 1.7-5.8). Totally 81 patients (14.7%) had sentinel headache within the last week before stroke and one control. Attacks of arrythmia during seven days before stroke were significantly associated with sentinel headache (p = 0.04, OR 2.3; 95% CI 1.1-4.8). Conclusions: A new type of headache and a previous kind of headache with altered characteristics during one week before stroke are significantly more prevalent than in controls. These headaches represent sentinel headaches. Sudden onset of such headaches should alarm about stroke. © 2020 The Author(s)

Morphometric characteristics of the intercondylar fossa according to magnetic resonance imaging

The results of magnetic resonance imaging of the knee were analyzed in 53 (N = 53, 100%) of the patients for X-ray reference parameters of intercondylar fossa (ICF) of the femur (width, height, intercondylar index and backup space). The MRI, radiometric and statistical methods were used. On the basis of statistical analysis were identified: weak positive correlation (r = Pearson coefficient 0.2203) values of intercondylar index and backup space intercondylar fossa; very weak positive correlation between the value of intercondylar index and age of the patient. Strong positive correlation (rank correlation coefficient r Spearman = 0.9986) values of intercondylar index and sex of the patient has been identified.Проанализированы результаты магнитно-резонансной томографии коленного сустава у 53 (N = 53, 100%) пациентов на предмет рентгенометрического анализа референтных параметров межмыщелковой ямки (ММЯ) бедренной кости (ширина, высота, межмыщелковый индекс и резервное пространство). В работе использованы метод магнитно-резонансной томографии (МРТ), рентгенометрический и статистический методы исследования. На основании статистического анализа были выявлены: положительная слабая корреляционная связь (коэффициент r по Пирсону = 0,2203) величины межмыщелкового индекса и резервного пространства межмыщелковой ямки; положительная очень слабая корреляционная связь величины межмыщелкового индекса и возраста пациента. Была выявлена сильная положительная корреляционная связь (коэффициент ранговой корреляции r по Спирмену = 0,9986) величины межмыщелкового индекса и пола пациента

The influence of bone substitute material on mechanical properties of trabecular bone in augmentation of intra-articular impression fractures. Experimental study

The purpose was to evaluate the effect of bone substitute materials on mechanical properties of trabecular bone adjacent to the joint. Material and methods A total of 21 female chinchilla rabbits weighing 3-3.5 kg was used for the experimental study. A bilateral impression fracture was simulated in the medial tibial condyle and surgically augmented with one of the bone substitution materials: beta-tricalcium phosphate, xenoplastic material and carbon nanostructures. The animals were sacrificed at 6, 12 and 24 weeks postsurgery. Uniaxial compression test was performed to determine mechanical properties of the tibial fragments. Bone microstructure was evaluated with scanning electron microscopy. Statistical data analysis was performed with nonparametric tests. Results Beta-tricalcium phosphate augmentation of the bone interface led to slow resorption accompanied by formation of adequate high-grade bone tissue with mechanical properties gradually increasing with greater observation time that indicated to the bone substitute integrated well with the host bone of the impression bone defect. Xenoplastic augmentation resulted in rapid resorption accompanied by formation of immature bone with mechanical properties declining at 6 to 12 weeks of observation. Carbon nanostructure augmentation of the bone interface caused perifocal bone resorption and absence of osteointegration with mechanical properties declining at 12 to 25 weeks of observation. © Gilev M.V., Zaytsev D.V., Izmodenova M.Y., Kiseleva D.V., Volokitina E.A., 2018