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The study examined the effects of two methods of processing de-hulled sunflower seed meal (SFM) from the same batch of sunflower seeds. Sunflower seed meal was fed to broilers as meal (MSFM) or after it had been pelleted (PSFM) at 75 °C and 360 kPa pressure to pass through a 3 mm mesh. Three diets were prepared, namely a balancer feed (BF) and two diets containing 200 g/kg MSFM or 200 g/kg PSFM. They were fed to 30 pens (two birds each) with male Ross 308 broilers, from 8 to 21 days old, following randomization. Data were analysed by ANOVA. Two pre-planned orthogonal contrast tests were performed to compare overall differences between the diets containing SFM and BF and between diets containing the MSFM and PSFM. The BF had a very different nutrient composition from the complete feeds containing SFM so, as expected, there were differences in growth performance and nutrient retention. The diet containing PSFM had greater apparent metabolizable energy corrected for N retention (AMEn) and dry matter retention (DMR) than that containing MSFM. The use of the substitution method showed the PSFM had AMEn that was 18% greater than the MSFM (8.79 vs 7.47 MJ/kg DM). Under the conditions of the current study, incorporating PSFM in a mash broiler feed increased dietary AMEn compared with the same feed containing MSFM. Further studies are needed to identify whether the benefits of pre-pelleting SFM remain after this product has been incorporated in complete pelleted broiler feeds.

During the operation of electric induction motors used to drive passenger elevators, electro-mechanical transient processes occur, which can cause unacceptable dynamic loads and vibrations. In this regard, research is needed both at the design stage and for operating elevator systems to determine the arising impact currents and torques, in order to propose solutions for their limitation within pre-set limits. Paper deals with starting processes in a two-speed induction motor drive of a passenger elevator. The equations for the voltages of the induction motor are presented in relative units in a coordinate system rotating at a synchronous speed. The values have been obtained for the torques, the rotational frequencies and the currents when starting at a high speed and passing from high to low speed.

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Netherlands Cardio Vascular Research Initiative (CVON): the Dutch Heart Foundation, Dutch Federation of University Medical Center, the Netherlands Organization for Health Re-search and Development and the Royal Netherlands Academy of Sciences Introduction Sudden cardiac death (SCD) is one of the severe manifestations in carriers with a phospholamban (PLN p.Arg14del) cardiomyopathy. Prediction whether a patient with this pathogenic variant will be at risk for SCD is difficult. PLN has an important role in cardiac calcium homeostasis as regulator of the sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA). It has been shown that the p.Arg14del pathogenic variant leads to Ca2+ overload in cardiomyocytes. Recently, it was found that dilated cardiomyopathy (DCM) patients who have a polymorphism in histidine-rich calcium binding protein (HRC Ser96Ala, rs3745297), displayed an increased risk for malignant arrhythmias and SCD. HRC resides within the SR, where it acts as a regulator of Ca2+ homeostasis. This Ser96Ala gene variant is widespread, as 60% of the general population bears at least one copy of this allele. Objective To explore the effect of the HRC Ser96Ala polymorphism on ventricular arrhythmias and disease expression in PLN p.Arg14del pathogenic variant carriers. Methods 337 p.Arg14del patients were included into the study; divided into wildtype (WT) (n=134, 24 index patients), heterozygous for Ser96Ala variant (n=142, 30 index patients) and homozygous for Ser96Ala variant (n=61, 11 index patients). The study was conducted according to the Declaration of Helsinki. Blood samples were genotyped on the Infinium® Global Screening Array-24 v3.0. Clinical data were subtracted from health records. Results In total 23% of PLN variant carriers were diagnosed with DCM while 11% of the variant carriers were diagnosed with arrhythmogenic cardiomyopathy. A significant difference in age of presentation (p=0.019) of p.Arg14del patients diagnosed with a DCM phenotype was found in homozygous HRC variant carriers (median 43 years, [36-47.3], n=8) compared to WT (median 49 years, [41-56.8], n=24) and heterozygous variant carriers (median 58.5 years, [51-66.5], n=22). No significant differences between the 3 groups were detected in manifestations of premature ventricular contractions (n=188, p=0.203), non-sustained ventricular tachycardia (n=248, p=0.314) and appropriate ICD shocks (n=308, p=0.901). Conclusion Although a significant difference in disease onset was found in PLN p.Arg14del patients with DCM who were homozygous for the HRC polymorphism, no correlations with arrhythmogenic parameters were found between patients with and without the HRC polymorphism. Therefore, we conclude that presence of the HRC polymorphism is not a discriminative predictor for arrhythmogenic events in PLN p.Arg14del.

Although a number of epidemiological studies have examined the effects of non-optimal temperatures on mortality in Europe, evidence about the mortality risks associated with exposures to hot and cold temperatures in Bulgaria is scarce. This study provides evidence about mortality attributable to non-optimal temperatures in adults aged 65 and over in Sofia, Bulgaria, between 2000 and 2017. We quantified the relationship between the daily mean temperature and mortality in the total elderly adult population aged 65 and over, among males and females aged 65 and over, as well as individuals aged 65-84 and 85 years or older. We used a distributed lag non-linear model with a 25-day lag to fully capture the effects of both cold and hot temperatures and calculated the fractions of mortality attributable to mild and extreme hot and cold temperatures. Cold temperatures had a greater impact on mortality than hot temperatures during the studied period. Most of the temperature-attributable mortality was due to moderate cold, followed by moderate heat, extreme cold, and extreme heat. The total mortality attributable to non-optimal temperatures was greater among females compared to males and among individuals aged 85 and over compared to those aged 65 to 84. The findings of this study can serve as a foundation for future research and policy development aimed at characterizing and reducing the risks from temperature exposures among vulnerable populations in the country, climate adaptation planning and improved public health preparedness, and response to non-optimal temperatures.

Summary Preterm birth is the most common cause of perinatal morbidity and mortality worldwide. The routine method for predicting premature birth is the measurement of the cervical length. However, to make a better and more precise prognosis, the cervicovaginal fluid (CVF) was widely inspected through many studies. Its content is used nowadays as a diagnostic method for different conditions. One of the clinical biomarkers used to predict preterm labour in the CVF is the phosphorylated insulin-like growth factor binding protein-1 (pIGFBP-1). This study aimed to evaluate the accuracy of pIGFBP-1 as a predictor of preterm labour when used with cervical biometrics. A prospective, cross-sectional study was conducted on pregnant patients, divided into groups: Group A included participants at risk for premature labour, and Group B -women with an uncomplicated pregnancy. All patients underwent a test for pIGFBP-1, followed by a transvaginal measurement of the cervical length. A total of 32 patients were recruited for the study. Their pregnancy outcomes were followed up. In the group of symptomatic patients, the results were positive in 8 patients, and despite the intensive tocolytic therapy given, 5 of them gave preterm birth within 14 days. There were two patients with a cervical length of less than 10 mm. They both had positive results for pIGFBP-1 and gave spontaneous preterm birth within a few hours. The predictive value of pIGFBP-1 in cases with negative results was high. The leading cause for fetal morbidity and mortality in the twenty-first century remains premature delivery. Many investigations are currently carried out, aiming to facilitate preterm labor prediction and quickly estimate a pregnant woman’s ability to carry to time. The patients at highest risk are detected by measuring the cervical length. Newly searched clinical biomarkers such as fetal fibronectin found in the CVF might help predict preterm birth in time.

Summary Nursing degree courses in Bulgaria provide a wide range of career opportunities to graduates. These opportunities, however, do not solve the current problems of the healthcare system. This communication presents the results of a survey conducted among graduate students majoring in the nursing specialty at the Medical University in Pleven. The survey aimed to acquire information on the graduates’ willingness to practice in nurseries. A questionnaire containing 26 questions specially designed for the study was used. The data were processed with statistical software packages Statgraphics; SPSS v. 19 and Excel for Windows. Despite the sound theoretical and practical course of training, 13 (21.67%) of the students were embarrassed, and 13 said they had been cautious when they first entered a crèches during their training. Almost half of the respondents – 29 (48.33%) reported that they might work in a crèches only if it is necessary, and 16 (26.66%) – never. Only 9 (15.00%) declared they would be committed to caring for children aged one to three years. At the end of their training, student nurses did not feel sufficiently prepared for the psychological and pedagogical challenges to practice their profession in such child day care centers. The respondents had no clear idea of the role of the nurse in a crèches. Very few of the student nurses reported a willingness to work in a crèches.

The distribution and relative amounts of six genera of lycophyte microspores, Lycospora , Densosporites , Crassispora , Cirratriradites , Endosporites and Cadiospora , are compared in the Pennsylvanian coals from the Dobrudzha and Forest of Dean coalfields, clastic sediments from the Glace Bay borehole in the Cape Breton Coalfield, and the southern crop of the South Wales coalfield. Inverse relationships are shown between Lycospora and Densosporites and between Lycospora and Crassispora in samples from all of the coalfields. The changes in microspore assemblages suggest there were at least five different communities of lycophyte plants growing in the Pennsylvanian swamps. Changes in microspore assemblages at the Asturian/Cantabrian boundary mirror the previously described macrofloral changes at this time.

One of the main reasons for the urban noise are the cars. When the hybrid cars are moved in low-speed mode, reduced noise is supposed. In the presented paper have been made comparative analysis according to standard methods of the external and internal sound levels of a hybrid car. The experiment at different speeds in two modes – using ICE and using electric traction were carried out. The results of the measurements are visualized in graphs and tables. They show variation of external and internal sound levels at different speeds in separate octave bands. Spectral analysis at each speed is done. The results show changing of sound level vs speed and noise predominant maximums at respective frequencies.

Late Permian fluvio-lacustrine successions of the Cakraz Formation in the Zonguldak Terrane between the regions of Akcakoca and Eregli were investigated in order to describe the litho- and biostratigraphic properties and explain the depositional environment. The studied succession with black, dark-grey to greenish-grey shales, siltstones and limestones is named the Alapli Member to distinguish it from the classical red clastic successions, which are tentatively named the Eregli Member of the Cakraz Formation. The organic-rich black shales, mudstones and limestones of the Alapli Member yielded palynological assemblages suggesting a Lopingian (Tatarian) age. The lack of any marine macro- or microfossils, the fine-grained character of the lithofacies with abundant plant material and the association of poorly sorted conglomerates in the middle part of the succession indicate possible deposition in a broad range of fluvial and lacustrine environments. Successions of similar age and depositional environment are known from the East European Variscan Belt in Bulgaria and Romania. Common successions were also developed in actively extending shallow-marine platforms on the NW Palaeotethyan margin at the end of the Permian Period.

The paper presents the results from a research on parts used in mechatronic products and produced by the permanent-mold casting methods of gravity die casting and die casting. An overview and analysis of different definitions for mechatronic systems and examples of mechatronic products is made. As a result, a new definition for a mechatronic product is proposed. Various classifications of mechatronic products are analysed and deemed too general for the purposes of the current research. Permanent-mold casting methods are analysed and their advantages and disadvantages are pointed out. Arguments as to why these methods are suitable for producing mechatronic product parts are given. Based on the proposed definition for mechatronic product, the analysed classifications, and the overview of the permanent-mold casting methods a new classification is proposed. The classification is used for classifying permanent-mold cast parts used in mechatronic products. The parts are classified in six groups with regard to their application in the mechatronic product. In addition, the classification gives information regarding permanent-mold casting method used, material, and mechatronic product that includes the part.

Polycystic ovary syndrome (PCOS) is a leading cause of anovulatory infertility. In recent times, autoimmune processes are supposed to play a role in a number of conditions with unexplained etiology. This includes some cases of human infertility. The attempts to detect antiovarian antibodies in patients with PCOS generally produced negative results. Presence of non-organ specific autoantibodies in patients with polycytosis has been reported, but the data are till inconsistent. Meanwhile, a number of recent sludies reveal a correlation between PCOS, hypothyroidism (manifested or subclinical) and autoimmunity. In this respect, many authors recommend thyroid function to be regularly checked in patients with PCOS. There are data that certain categories of women with polycystosis show an elevated concentration of antisperm antibodies. The problem is an interesting example how a pathological process can elucidate the complex interactions between the immune system and various compartments of the endocrine system that include immunologically isolated antigens.

A test rig for study of parameters of a process of automated assembly of luster terminals is designed and developed. The aim of the developed test rig is to study the accuracy of positioning of the transport system during the automated assembly process of luster terminals. On the basis of data collected during the experiments, reliability analysis of the whole system has been made.

Pollen preserved in latest Westphalian and early Stephanian clastic deposits of the Sydney Coalfield, Cape Breton Island, suggest that there were zones of different vegetational habitats surrounding the wetlands where the coal-forming peat was formed. On the margins of the wetlands was a narrow band with large cordaitanthacean trees. This was surrounded by ‘occasionally dry9 habitats supporting Schuetzia -plants, ruflorioid-plants and Aethophyllum -like herbaceous conifers. Around this were mesic or seasonally dry habitats, dominated by walchian conifers and disaccate-producing peltasperms. These in turn were surrounded by xeric or seasonally wet habitats, dominated by ullmanniacean-like conifers, cycads and monosaccate-producing peltasperms. During latest Westphalian and early Stephanian times, the mesic and xeric habitats encroached nearer the wetlands, although the vegetation of the wetlands themselves remained essentially unaffected. This vegetation change was not a response to climate change, but probably to changing drainage patterns and topography in the surrounding hinterland. The Florinites -producing cordaitanthaceans appear not to have been upland trees, as previously suggested, but occupied mainly coastal habitats, or riparian habitats on the margins of the wetlands.

A synthesis of the upper Moscovian sedimentological and palaeontological record of terrestrial habitats across the Variscan foreland and adjacent intramontane basins (an area which is referred to here as Variscan Euramerica) suggests a contraction and progressive westward shift of the coal swamps. These changes can be correlated with pulses of tectonic activity (tectonic phases) resulting from the northwards migration of the Variscan Front. This tectonic activity caused disruption to the landscapes and drainage patterns where the coal swamps were growing, which became less suitable to growth of the dominant plants of the swamps, the arborescent lycopsids. They were progressively replaced by vegetation dominated by marattialean ferns, which through a combination of slower growth and larger canopies resulted in less evapo-transpiration. This in turn caused localised reductions in rainfall, which further affected the ability of the lycopsids to dominate the swamp vegetation. These changes were initially localised and where the coal swamps were able to survive the lycopsids and pteridosperms show little change in either species diversity or biogeography, indicating that at this time there was minimal regional-scale climate change taking place. By Asturian times, however, the process had accelerated and the swamps in Variscan Euramerica became progressively replaced by predominantly conifer and cordaite vegetation that favoured much drier substrates. Except in localised pockets in intramontane basins of the Variscan Mountains, the last development of coal swamps in Variscan Euramerica was of early Cantabrian age. Further west, lycopsid-dominated coal swamps persisted for a little longer. The last remnants of the lycopsid-dominated coal swamps in the Illinois Basin disappeared probably by middle-late Cantabrian times, as the cycle of contracting wetlands and regional reductions in rainfall generated its own momentum, and no longer needed the impetus of tectonic instability. This tectonically-driven decline in the Euramerican coal swamps was probably responsible for an annual increase in atmospheric CO2of c. 0.37 ppm, and may have been implicated in the marked increase in global temperatures near the Moscovian – Kasimovian boundary, and the onset of the Late Pennsylvanian interglacial.

The object of the present study was to study if there are differences in the presence of CD4-like molecules on human ejaculated spermatozoa in fertile donors and infertile patients (with globozoospermia). Indirect and absorption enzyme-linked immunosorbent assay and indirect immunofluorescence were applied. The enzyme-linked immunosorbent assay data showed that monoclonal anti-human CD4-antibody recognizes an epitope common to the human spermatozoa with normal morphology and round-headed spermatozoa. Localization of the antigenic determinants, identified by anti-human CD4-monoclonal antibody, in the acrosomal region, including equatorial segment, postnuclear cap and tail was determined in normozoospermic samples. A positive reaction was found on the sperm head both in the acrosomal and postacrosomal region of some round-headed spermatozoa in the samples with globozoospermia. The tails of the normozoospermic spermatozoa and of some round-headed spermatozoa were weakly immunopositive. The results of the experiments carried out are evidence of heterogeneity in the presence of CD4-like antigen determinants on human spermatozoa. These data increased the information about the CD4-antigen characteristic of the spermatozoa from fertile donors and infertile patients.

Several kinds of thymic cells express MHC class II antigens, including human-leukocyte-associated antigen-DR (HLA-DR) during postnatal development. The present study was focused on the detection and analysis of HLA-DR immunoreactivity in human fetal thymuses (6-7th month of gestation). Using monoclonal antibodies, indirect immunoperoxidase staining (IIP), immunogold electron microscopy (IGEM), enzyme-linked immunosorbent assay (ELISA) and flow cytometry, HLA-DR immunopositive (IP) thymic cells were found in samples studied. IIP and IGEM demonstrated the presence of HLA-DR IP stromal cells (SCs): epithelial cells (ECs), dendritic-like cells (DCs) and macrophages (MCs) as well as HLA-DR IP lymphocytes (Lys) in all thymic regions. HLA-DR immunoreactivity was more prominent in the medullary ECs (mECs) than in the cortical ECs (cECs). Strong staining of Hassall's corpuscles and the adjacent mECs was seen. The differences in the intracellular distribution of HLA-DR molecules were detailed by IGEM as a first attempt to analyse HLA-DR IP cells at ultrastructural level. ELISA data and two-colour flow cytometric analysis revealed the presence of HLA-DR IP and HLA-DR/CD3 double IP Lys in accordance with the immunocytochemical assays. The results presented enrich the information about HLA-DR IP components of the thymic microenvironment in developing human thymus and raise the question of their role during prenatal T cell differentiation and selection processes.

Dark matter is a hypothesized form of matter that does not reflect or emit electromagnetic radiation. The existence of dark matter is inferred from gravitational effects on visible matter, such as stars and galaxies. Coma Galaxy Cluster is one of the strongest evidence that the Universe is predominantly composed of some form of unseen matter. In this paper, we use new data in order to estimate the virial and the visible mass of Coma Galaxy Cluster. It turns out that after 76 years since the hypothesis for existing of dark matter was propounded, the problem with the missing mass in galaxies and clusters is still unresolved.

A new Certified Reference Material (CRM) for radionuclides in sediment (IAEA-385) is described and the results of the certification process are presented. Eleven radionuclides ((40)K, (137)Cs, (226)Ra, (228)Ra, (230)Th, (232)Th, (234)U, (238)U, (238)Pu, (239+240)Pu and (241)Am) have been certified and information mass activities with 95% confidence intervals are given for seven other radionuclides ((90)Sr, (210)Pb((210)Po), (235)U, (239)Pu, (240)Pu and (241)Pu). Results for less frequently reported radionuclides ((60)Co, (99)Tc, (134)Cs, (155)Eu, (224)Ra and (239)Np) and information on some activity and mass ratios are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in sediment samples, for the development and validation of analytical methods and for training purposes.

A lot of extensive investigations have been conducted to evaluate the potential role of antisperm antibodies (ASA) in infertile couples. But many questions still remain on the role of ASA in reproduction, testing methods, significant levels of ASA and treatment of immunologically-mediated human infertility, due to ASA. The aim of the present critical review was to the analyze the literature data, published in the last 20 years, concerning the most frequently used in the international centers methods for treatment of human immunological infertility associated with ASA production.

Among others, immunological factors can be the reason for human infertility. The aim of the present critical review was to the analyze the literature data, published in the last 20 years, as well as our experimental and clinical results concerning the most frequently used in the international centers methods for the detection of antisperm antibodies associated with immunologically--mediated human infertility.

Establishing the age-dependent patterns of sperm antibody levels among normal humans.Sera samples from 498 healthy subjects aged 0-97 years - 246 males and 252 females - were tested by the gelatin agglutination test of Kibrick, tray agglutination test of Friberg, sperm immobilization test of Isojima and enzyme-linked immunosorbent assay (ELISA).We found a significant increase in the level of sperm agglutinins after 40 years, which decreased after 88 years. The antibodies detected by ELISA were the highest among prepubertal subjects and also declined with aging. No age-dependent changes were established for the sperm immobilizins. With few exceptions, there were no significant differences between male and female sera, as well as between sera of newborn and their mothers.These data are similar to those established for the age-dependent changes of antibodies towards exogenous antigens, suggesting that the 'naturally occurring' antibodies against human spermatozoa are not auto-/isoantibodies.

Among others, immonulogical factors can be the reason for human infertility. Our critical review of English-Language literature published between 1979 and May 2001, as well as the analyzed literature data for the Bulgarian population, showed sufficient evidence that antisperm antibodies impair fertility in couple with unexplained infertility by different pathogenetic mechanisms.

The object of the present study was to investigate whether there were differences in the presence of CD8-like molecules on human ejaculated spermatozoa from fertile donors and subfertile patients (with leucocytospermia). In our previous report we defined CD4-like molecule heterogeneity on normozoospermic and globozoospermic human spermatozoa. In this investigation the results from indirect and absorption ELISA, as well as the indirect IEM and IIF findings, demonstrated the presence of CD8 immunopositive spermatozoa in all samples studied. The ELISA data showed that anti-human MoAb CD8 recognized an epitope common to the human spermatozoa with normal morphology and foetal thymocytes. During absorption experiments MoAb CD8 was preincubated with spermatozoa and allowed to react with thymocytes. A significant decrease of the reactivity was obtained for MoAb CD8 by ELISA. Localization of the antigenic determinants, identified by MoAb CD8, in the acrosomal region, in the neck and on the sperm-tail plasma membrane was defined in normozoospermic samples. Similar in localization but different in intensity, CD8-like sperm immunoreactivity was found in leucocytospermic samples in comparison to normozoospermic samples. The obtained results proved the heterogeneity in the presence, localization and expression of CD-like antigen determinants on human spermatozoa and enlarged the information about CD8-like antigen characteristics of the spermatozoa from fertile donors and subfertile patients.

Epstein-Barr virus (EBV)-transformed B cell lines that produce human antisperm antibodies were established using peripheral blood lymphocytes (PBLs) from infertile women with sperm immobilizing antibodies in their sera. We obtained three stable cell populations (designated B1, B2, D5) of transformed PBLs originating from three different patients. They produced IgM sperm-reacting antibodies directed against the tail of live, methanol-fixed and NaIO4-treated human spermatozoa. The established antisperm antibodies recognized noncarbohydrate sperm membrane antigens with different specificity and distribution in the male reproductive system. Antisperm antibody-B2 corresponding antigen appears to be specific for the male reproductive system. This antigen is excreted from the epithelial cells of the ductus epididymidis and bound to the spermatozoa in the lumen of the ductus. Antisperm antibodies B1 and D5 corresponding antigens were expressed on the spermatozoa in the seminiferous tubules and were common to the secretions of the ductus epididymidis, prostate and some other somatic organs. The cDNA of the immunoglobulin heavy chain genes were analyzed by reverse transcription polymerase chain reaction (RT-PCR) using RNA extracted from these clones. The immunoglobulin heavy chain cDNA sequences of these antisperm antibodies showed extremely high homology to previously reported immunoglobulin germline DNA sequences, implying that these antisperm antibodies might be natural autoantibodies rather than antibodies stimulated by external antigen.

Semiconducting materials, based on the compounds PbTe and AgSbTe2, are studied. The following characteristics of single and polycrystalline samples, obtained by the Bridgman method, are studied: temperature dependence of the Hall coefficient (RH), thermoelectric power coefficient (α), Hall, mobility (μ), and thermal conductivity (χ) in the 100 to 500 K range. The thermoelectric efficiency Z of all the studied compositions is evaluated. The optimum Z-value is > 3 × 10−3 K−1 at × = 0.9 (400 K). [Russian Text Ignored].

A series of new cheating sorbents has been prepared by modification of styrene-divinylbenzene copolymer with different pyrazolone-containing amines. The substances were characterized by elemental analysis and infared spectroscopy. The complexation ability of the sorbents towards alkali, alkaline-earth, transition and precious metals has been studied. The new sorbents may successfully be applied to the simultaneous preconcentration of alkaline-earth and transition elements in neutral medium and to the selective separation of precious metals in acidic medium.

It has been shown that mixtures of phenobarbital and 3- methylcholantrene may be used in the Salmonella/microsome test as inductors of the S9 liver fraction, instead of "Aroclor 1254". The Salmonella/microsome method has been used to study the mutagenic action of Flatogel (2.5% polymethylsyloxanum activatum and 2% ethylium -p- aminobenzoicum , suspended in sorbitol-balanced gel of aluminum hydroxidatum and magnesium hydroxidatum ), Nitrolong (2,2-bis/hydroxymethyl/-1,3- propandioltetranitrate ) and Cymethidine (N-cyano-N'-methyl-N"/2-/5-methyl-4-imidazolyl-methylthio/ethyl/guanidin e). These substances are produced as drugs by the Bulgarian chemical and pharmaceutical industry ( PHARMACHIM ). The results obtained show that the drugs studied have no mutagenic action, both without and with activation with S9 liver fraction isolated from rats treated with "Aroclor 1254" or combinations of phenobarbital and 3- methylcholantrene .