Improvements in the Global A-Posteriori Error Estimation of the FEM and MFDM Solutions

The present paper deals with the estimation of the solution error of the boundary value problems of mechanics science. The well-known ideas of error estimators are presented, as well as new original ones, which use the concept of the improved HO reference solution, obtained using the Meshless Finite Difference Method analysis. Such HO estimators may be applied not only in the MFDM, but also in the Finite Element Method error analysis. This issue is presented here for the first time ever. The approach is tested on chosen 2D benchmark problems. The results are very encouraging

Oocyte zona pellucida and meiotic spindle birefringence as a biomarker of pregnancy rate outcome in IVF-ICSI treatment

Objectives: IVF-ICSI procedures are accompanied by a continuous search for predictors of ART outcome. The properties of zona pellucida (ZP) have been believed to reflect the history of oocyte cytoplasmic maturation. The meiotic spindle (MS) is crucial for chromosomal alignment and proper separation of the maternal chromosomes. There is data suggesting that birefringent ZP and MS can clinically predict the oocyte quality and developmental potential of an embryo. The aim of the study was to examine the possible effect of ZP birefringent properties and MS visualization and localization as valuable predictors of IVF-ICSI effectiveness. Material and methods: The prospective study was performed during a 16-month period. A total of 51 patients undergoing in vitro fertilization - embryo transfer (IVF-ET) treatment procedure with intracytoplasmic sperm injection (ICSI) were included. Controlled ovarian hyperstimulation (COH) was done using either a long n=32 (62.75%) or an antagonist protocol n=19. In the group of the 48 examined patients (aged 25-40), 46 ET were performed, resulting in 24 positive pregnancy tests and 19 (39.59%) clinical pregnancies. Oocytes were examined as follows: ZP birefringence autoscoring (OCTAX PolarAIDE), numeral autoscoring, thickness and clinical evaluation; MS visualization, if MS was visualized, localization of MS in relation to the polar body (PB). Results: On day 3, 64.3% of the embryos were of good and 40.3% were of top quality. Visible differences, not statistically significant, were observed in the numeral score of ZP between oocytes selected and non-selected for ET. In cases when embryos were not of good or top quality, ZP score was higher (p=0.005 p=0.001). ZP manual evaluation indicated significantly stronger birefringence when pregnancy was not achieved (p=0.022). The rate of MS positive oocytes was the highest in the group with pregnancy, but it did not reach statistical significance (p=0.471). The MS localization in relation to the PB was in most oocytes very close

Analiza profilu demograficznego pacjentów leczonych z powodu niepłodności metodami rozrodu wspomaganego w latach 2005-2010

Objectives: analysis of the demographic profile of patients, causes for infertility and effectiveness of infertility treatment methods in the years 2005-2010. Material and methods: Retrospective research was conducted to analyze data of 1705 randomly selected couples who underwent in vitro fertilization procedure at the Department of Reproduction and Gynecological Endocrinology, Medical University of Bialystok, between 2005 and 2010. The analyzed data included mainly causes for infertility, age of the female and male subjects, place of residence and final treatment results. Results: The percentage of pregnancy rate increased significantly to approximately 40% in 2007. The contribution of male and female infertility factors remained at a similar level, but the idiopathic factor continued to steadily increase (to 20% in the last years of the study). We observed a greater prevalence of the male factor among couples living in cities compared to inhabitants of rural areas (42.3% vs. 34.3%, p=0.004), whereas the tubal factor dominated among couples living in the countryside when compared to city dwellers (29.7% vs. 21.6%, p=0.001). The average age of women entering treatment was significantly higher in cities than the countryside (pCel pracy: Analiza profilu demograficznego pacjentów, przyczyn niepłodności oraz skuteczności leczenia metodami rozrodu wspomaganego w latach 2005-2010. Materiał i metody: W badaniu retrospektywnym przeanalizowano dane dotyczące 1705 losowo wybranych cykli leczenia niepłodności metodami rozrodu wspomaganego, przeprowadzonych w latach 2005-2010 w Klinice Rozrodczości i Endokrynologii Ginekologicznej Uniwersytetu Medycznego w Białymstoku. Wyniki: Odsetek uzyskanych ciąż wyraźnie wzrósł w 2007 roku do poziomu około 40%. Udział męskich i żeńskich czynników niepłodności kształtuje się na porównywalnym poziomie, stale wzrasta udział czynnika niewyjaśnionego pochodzenia (do około 20% w ostatnich latach badania). Wśród par z miasta stwierdza się większy niż na wsi odsetek występowania czynnika męskiego (42,3% vs. 34,3%, p=0,004), natomiast u par ze wsi – większy niż w miastach udział czynnika jajowodowego (29,7% vs. 21,6%, p=0,001). Przeciętny wiek kobiet podejmujących leczenie jest istotnie wyższy w mieście niż na wsi (

Isolation of Bacteriocin-producing Staphylococcus spp. Strains from Human Skin Wounds, Soft Tissue Infections and Bovine Mastitis

A collection of 206 Staphylococcus spp. isolates was investigated for their ability to produce compounds exhibiting antistaphylococcal activity. This group included Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus xylosus strains recovered from bovine mastitis (n = 158) and human skin wounds and soft tissues infections (n = 48). Production of substances with antimicrobial activity was observed in six strains. Five of them were recovered from bovine mastitis, and one was isolated from the infected human skin wound. Three of the six antimicrobials produced by the different strains showed substantial loss of antimicrobial activity upon treatment with proteolytic enzymes, which suggests their peptidic structure. Additional studies have shown that one of the putative bacteriocins was efficiently secreted to the liquid medium, facilitating its large-scale production and isolation. The peptide produced by the M2B strain exhibited promising activity; however, against narrow spectrum of Staphylococcus spp. clinical and animal isolates. Growth inhibition was observed only in the case of 13 (including nine S. aureus, three S. xylosus and one S. epidermidis strains) out of 206 strains tested. Important advantage of the produced agent was its high thermal stability. Fifteen minutes of incubation at 90°C did not affect its antimicrobial potential. The highest efficiency of production of the agent was demonstrated in TSB medium after 24 hours at 37°C. The researches revealed that ability to production of bacteriocin among staphylococci is not very common. Only one (S. xylosus strain assigned as M2B) out of 206 strains tested produced satisfactory amounts of antistaphylococcal bacteriocin. In spite of that, we would encourage other researchers for investigation of their collections of Staphylococcus spp. isolates towards selection strains producing antimicrobial agents

Prognosis of the IVF ICSI/ET procedure efficiency with the use of artificial neural networks among patients of the Department of Reproduction and Gynecological Endocrinology

Summary Objectives: Prognosis of pregnancy for patients treated with IVF ICSI/ET methods, using artificial neural networks. Material and methods: Retrospective study of 1007 cycles of infertility treatment of 899 patients of Department of Reproduction and Gynecological Endocrinology in Bialystok. The subjects were treated with IVF ICSI/ET method from August 2005 to September 2008. Results: Classifying artificial neural network is described in the paper. Architecture of the network is three-layered perceptron consisting of 45 neurons in the input layer, 14 neurons in the hidden layer and a single output neuron. The source data for the network are 36 variables. 24 of them are nominal variables and the rest are quantitative variables. Among non-pregnancy cases only 59 prognosis of the network were incorrect. The results of treatment were correctly forecast in 68.5% of cases. The pregnancy was accurately confirmed in 49.1% of cases and lack of pregnancy in 86.5% of cases. Conclusions: Treatment of infertility with the use of in vitro fertilization methods continues to have too low efficiency per one treatment cycle. To improve this indicator, it is necessary to find dependencies, which describe the model of IVF treatment. The application of advanced methods of bioinformatics allows to predict the result of the treatment more effectively. With the help of artificial neural networks, we are able to forecast the failure of the treatment using IFV ICSI/ET procedure with almost 90% probability of certainty. These possibilities can be used to predict negative cases

Long range molecular dynamics study of regulation of eukaryotic glucosamine-6-phosphate synthase activity by UDP-GlcNAc

Glucosamine-6-phosphate (GlcN-6-P) synthase catalyses the first and practically irreversible step in hexosamine metabolism. The final product of this pathway, uridine 5’ diphospho N-acetyl-D-glucosamine (UDP-GlcNAc), is an essential substrate for assembly of bacterial and fungal cell walls. Moreover, the enzyme is involved in phenomenon of hexosamine induced insulin resistance in type II diabetes, which makes it a potential target for antifungal, antibacterial and antidiabetic therapy. The crystal structure of the isomerase domain of GlcN-6-P synthase from human pathogenic fungus Candida albicans, in complex with UDP-GlcNAc has been solved recently but it has not revealed the molecular mechanism of inhibition taking place under UDP-GlcNAc influence, the unique feature of the eukaryotic enzyme. UDP-GlcNAc is a physiological inhibitor of GlcN-6-P synthase, binding about 1 nm away from the active site of the enzyme. In the present work, comparative molecular dynamics simulations of the free and UDP-GlcNAc-bounded structures of GlcN-6-P synthase have been performed. The aim was to complete static X-ray structural data and detect possible changes in the dynamics of the two structures. Results of the simulation studies demonstrated higher mobility of the free structure when compared to the liganded one. Several amino acid residues were identified, flexibility of which is strongly affected upon UDP-GlcNAc binding. Importantly, the most fixed residues are those related to the inhibitor binding process and to the catalytic reaction. The obtained results constitute an important step toward understanding of mechanism of GlcN-6-P synthase inhibition by UDP-GlcNAc molecule

Introduction to the numerical homogenization by means of the Meshless Finite Difference Method with the Higher Order Approximation

Abstract Paper focuses on application of the Meshless Finite Difference Method (MFDM) solution approach and its selected extensions to the numerical homogenization of the heterogeneous material. The most commonly used method of computer modeling for the multiscale problem (at both the macro and micro (RVE) levels) is the Finite Element Method (FEM). However, this fact does not mean that one should not search for the alternative, perhaps more efficient approaches, especially based on the meshless discretization. The aim of this paper is to present a problem formulation for numerical homogenization based on the extended algorithm of the Meshless (Generalized) FDM. The Higher Order Approximation (HOA), which is applied here, is based on the correction terms of the simple meshless difference operator. Those terms produce the improved higher order solution, without necessity of providing additional unknowns to both cloud of nodes and MFD operator. The HO solution may be used e.g. for a-posteriori error estimation of superior quality, when compared with the existing estimation techniques. The paper is illustrated with simple tasks of 2D linear theory of elasticity, which highlight benefits of the considered approach towards more complex problems of mechanics

Investigation of the Antifungal Activity and Mode of Action of Thymus vulgaris, Citrus limonum, Pelargonium graveolens, Cinnamomum cassia, Ocimum basilicum, and Eugenia caryophyllus Essential Oils

The antimicrobial activity of plant oils and extracts has been recognized for many years. In this study the activity of Thymus vulgaris, Citrus limonum, Pelargonium graveolens, Cinnamomum cassia, Ocimum basilicum, and Eugenia caryophyllus essential oils (EOs) distributed by Pollena Aroma (Nowy Dwór Mazowiecki, Poland) was investigated against a group of 183 clinical isolates of C. albicans and 76 isolates of C. glabrata. All of the oils exhibited both fungistatic and fungicidal activity toward C. albicans and C. glabrata isolates. The highest activity was observed for cinnamon oil, with MIC (Minimum Inhibitory Concentration) values in the range 0.002–0.125% (v/v). The MIC values of the rest of the oils were in the range 0.005% (or less) to 2.5% (v/v). In most cases MFC (Minimum Fungicidal Concentration) values were equal to MIC or twice as high. Additionally, we examined the mode of action of selected EOs. The effect on cell wall components could not be clearly proved. Three of the tested EOs (thyme, lemon, and clove) affected cell membranes. At the same time, thyme, cinnamon, and clove oil influenced potassium ion efflux, which was not seen in the case of lemon oil. All of the tested oils demonstrated the ability to inhibit the transition of yeast to mycelium form, but the effect was the lowest in the case of cinnamon oil