130 research outputs found

    Micro-CT supporting structural analysis and modelling of ropes made of natural fibers

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    This paper describes the modelling of the structure and mechanical parameters of rope components made of natural fibers. Modern X-ray micro-tomography (Micro-CT) was employed to measure the parameters of the internal structure of the multi-component yarns making up rope and utilized as a basic model of twisted rope. The results allowed calculation of the tensions generated in the component yarns and detection of the unevenness of the filling of the component yarns by fibers, which was clearly visible in cross-section. The unevenness of twist measured as a function of distance from the center of the yarn was also detected. The unevenness of fiber distribution in the twisted element decreased its intensity, starting from the surface of the yarn and going deeper into the structure. Migration of the fibers in the frame of the circumference of the component yarns was associated with the mutual slide of single fibers

    Europejskie społeczeństwo gigabitowe

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    The aim of the paper is to present the European gigabit society which is perceived by European Union’s leaders as a model of the future European society and economy. It is based on new digital technologies of the XXI century and on new, very high capacity mobile telecommunications networks. The rapid growth of information being processed and transmitted through electronic communications networks needs new high-speed and highly reliable broadband networks essential to economic growth, competitiveness and innovation as well as better quality products, services and the citizen’s satisfaction. The 5G communications network is the solution which is perceived as a type of network which should resolve these problems. In the paper the concept of the European gigabit society is clarifi ed, the 5G technology and its level of development in the European Union and in its Member States are described including Poland vis-à-vis the rest of the world. The European gigabit society is already under development and the 5G communication network is crucial to its success. It should be widely available in Europe including Poland. The paper is based on the analysis of offi cial documents of the European Union and its Member States including Poland, offi cial reports of the most active electronic telecommunications companies providing and implementing 5G technologies and on talks with representatives of some of the ones which are active on the Polish market

    Von der Abfallpolitik zu einer nachhaltigen Stoffstrompolitik

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    Physiological aspects of sex differences and Haldane’s rule in Rumex hastatulus

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    Haldane’s rule (HR, impairment of fertility and/or viability of interracial hybrids) seems to be one of few generalizations in evolutionary biology. The validity of HR has been confirmed in animals, and more recently in some dioecious plants (Silene and Rumex). Dioecious Rumex hastatulus has two races differing in the sex chromosome system: Texas (T) and North Carolina (NC), and T × NC males showed both reduced pollen fertility and rarity—two classical symptoms of Haldane’s rule (HR). The reduced fertility of these plants has a simple mechanistic explanation, but the reason for their rarity was not elucidated. Here, we measured selected physiological parameters related to the antioxidant defense system in parental races and reciprocal hybrids of R. hastatulus. We showed that the X-autosome configurations, as well as asymmetries associated with Y chromosomes and cytoplasm, could modulate this system in hybrids. The levels and quantitative patterns of the measured parameters distinguish the T × NC hybrid from the other analyzed forms. Our observations suggest that the rarity of T × NC males is caused postzygotically and most likely related to the higher level of oxidative stress induced by the chromosomal incompatibilities. It is the first report on the physiological aspects of HR in plants

    PREPARATION AND PHOTOCATALYTIC ACTIVITY OF IRON- MODIFIED TITANIUM DIOXIDE PHOTOCATALYST

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    Abstract. Iron modified TiO 2 was prepared by the sol-gel method and surface modification method followed by calcination at 400°C. Two types of titanium dioxide: TiO2 ST-01(Ishihara Sangyo Ltd., Japan;300 m 2 /g), and TiO 2 P25 (Evonik, Germany, 50 m 2 /g) were used in the grinding procedure. The photocatalysts were characterized by UV-VIS absorption and BET surface area measurements. The photocatalytic activity of the obtained powders in UV-Vis and visible light was estimated by measuring the decomposition rate of phenol (0.21 mmol/dm 3 ) in an aqueous solution. The best photoactivity under visible light was observed for iron doped TiO 2 with 0.5% by grinding the TiO 2 ST-01

    Lack of expression of preproorexin and orexin receptors genes in human normal and prostate cancer cell lines

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    Introduction. Studies on expression of orexins (OXs) and their receptors in human prostate gland and human prostatic cell lines are scanty and their results contradictory. Regarding this, we carefully reinvestigated this problem on human prostatic cell lines. Material and methods. Expression of preproorexin (ppOX) (6 primer pairs), and orexin receptors 1 and 2 (OXR1, OXR2) (4 and 2 primer pairs, respectively) was assessed by conventional PCR and QPCR in human normal (PrEC, PrSc, PrSmC) and prostate carcinoma (Du145, LNCaP, and PC3) cell lines. We designed intron spanning primers and also we applied primers from earlier publications and commercially available ones. Results. With the designed primer pairs, in all studied cell lines we failed to demonstrate expression of ppOX, OXR1 and OXR2 genes at the mRNA level, while reaction products were observed in control tissues (human placenta and adrenals). Primers applied in earlier studies did not form amplification products specific for preproorexin or orexin 1 receptor. Some commercially available primers for orexin receptor 1 produced false positive results. Conclusions. We found no evidence for the presence of preproorexin–orexin receptors system genes’ mRNAs in human prostate cell lines. The reported premises for these genes’ expression in prostate and prostatic cell lines may have arisen either from the presence of non-prostate cells included in the samples or from faulty PCR settings

    Hormone concentration, metabolic disorders and immunoexpression of androgen and estrogen-alpha receptors in men with benign prostatic hyperplasia and testosterone deficiency syndrome

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    Introduction. A slight decrease in blood testosterone level in men is a physiological state associated with the aging. The aim of our study was to evaluate the occurrence of hormone and metabolic disorders, as well as the immunolocalization and immunoexpression of androgen receptors (AR) and estrogen-alpha receptors (ERa) in the prostates of men with benign prostatic hyperplasia (BPH) and coexisting testosterone deficiency syndrome (TDS). Material and methods. The study involved 150 men, diagnosed with and receiving pharmacological treatment for BPH. Concentrations of glucose, total cholesterol (TCh), high-density lipoproteins (HDL), low-density lipoproteins (LDL), and triglycerides (TG) were determined in blood serum. Serum concentrations of total testosterone (TT), free testosterone (FT), estradiol (E2), luteinizing hormone (LH), insulin (I), sex hormone-binding globulin (SHBG), dehydroepiandrosterone sulfate (DHEAS), and insulin-like growth factor 1 (IGF-1) were measured by ELISA. The number of AR-positive cells and ERa-positive cells were measured in prostate sections of men with BPH. Results. Patients eligible for transurethral resection of the prostate and TDS were significantly more likely to have higher abdominal circumference and higher serum levels of insulin and IGF-1 as well as lower levels of FT and SHBG than control subjects with BPH and no TDS. Quantitative analysis revealed 35.8% AR-positive colum­nar epithelial cells and 24.3% AR-positive stromal cells in prostates of BPH patients with TDS and 30.5% and 23.0%, respectively, in BPH patients without TDS. However, the differences between the study and the control groups were statistically not significant. In prostates of BPH patients with TDS the immunoexpression of ERa was observed in 2.88% of the columnar epithelial cells and 0.39% of stromal cells. In BPH patients without TDS ERa-positive cells were only found in 0.04% of columnar epithelial cells and 0.62% of prostatic stromal cells. Conclusions. Considering the statistically significantly higher levels of I and IGF-1 and larger abdominal circumference of men with BPH and TT deficiency, it can be supposed that visceral obesity and carbohydrate disorders may contribute to the reduction of testosterone concentration. The results of our study indicate a relationship between TT concentration in the plasma of patients with BPH and the percentage of AR-positive cells in the prostate.

    PFTAIRE Kinase L63 Interactor 1A (Pif1A Protein) Is Required for Actin Cone Movement during Spermatid Individualization in Drosophila melanogaster

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    A useful model for determining the mechanisms by which actin and actin binding proteins control cellular architecture is the Drosophila melanogaster process of spermatogenesis. During the final step of spermatogenesis, 64 syncytial spermatids individualized as stable actin cones move synchronously down the axonemes and remodel the membranes. To identify new genes involved in spermatid individualization, we screened a collection of Drosophila male-sterile mutants and found that, in the line Z3-5009, actin cones formed near to the spermatid nuclei but failed to move, resulting in failed spermatid individualization. However, we show by phalloidin actin staining, electron microscopy and immunocytochemical localization of several actin binding proteins that the early cones had normal structure. We sequenced the genome of the Z3-5009 line and identified mutations in the PFTAIRE kinase L63 interactor 1A (Pif1A) gene. Quantitative real-time PCR showed that Pif1A transcript abundance was decreased in the mutant, and a transgene expressing Pif1A fused to green fluorescent protein (GFP) was able to fully rescue spermatid individualization and male fertility. Pif1A-GFP localized to the front of actin cones before initiation of movement. We propose that Pif1A plays a pivotal role in directing actin cone movement

    Improving electrical and thermal surface properties of polymer composite materials

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    Treballs Finals de Grau d'Enginyeria Química, Facultat de Química, Universitat de Barcelona, Curs: 2016-2017, Tutores: Núria Llorca Isern, Ana Maria Escobar RomeroThe use of new composite materials has increase in the last decades due to the possibility to achieve great properties with the combination of two or more materials. A great example is carbon fibre reinforce polymers (CFRPs), which are intensively use in many applications for their good strength to weight ratio. These materials are apparently an ideal component for aircraft industrial; however, the electrical and thermal conductivity they exhibit makes it unsuitable for certain applications like lightening strike protection. To achieve better performance on CFRPs, it is common to metallise the surface with aluminium, copper or others conductive materials. In this project two different approaches have been compared: joining, with adhesive tape, and coating, with electrochemical deposition and sputtering. The electrical conductivity of the samples, before and after the metallization, has been studied with the 4-probes method and we have studied the influence of thickness on thermal and electrical conductivity

    Myogenic Differentiation of Mouse Embryonic Stem Cells That Lack a Functional Pax7 Gene

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    The transcription factor Pax7 plays a key role during embryonic myogenesis and sustains the proper function of satellite cells, which serve as adult skeletal muscle stem cells. Overexpression of Pax7 has been shown to promote the myogenic differentiation of pluripotent stem cells. However, the effects of the absence of functional Pax7 in differentiating embryonic stem cells (ESCs) have not yet been directly tested. Herein, we studied mouse stem cells that lacked a functional Pax7 gene and characterized the differentiation of these stem cells under conditions that promoted the derivation of myoblasts in vitro. We analyzed the expression of myogenic factors, such as myogenic regulatory factors and muscle-specific microRNAs, in wild-type and mutant cells. Finally, we compared the transcriptome of both types of cells and did not find substantial differences in the expression of genes related to the regulation of myogenesis. As a result, we showed that the absence of functional Pax7 does not prevent the in vitro myogenic differentiation of ESCs
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