Analiza mehaničkih svojstava F75 Co-Cr legure za primjenu kod selektivnog laserskog topljenja (SLT) izrade djelomičnih zubnih proteza

The presented work discusses the applicability of the selective laser melting technique (SLM) in manufacture of removable partial denture (RPD) frameworks with the emphasis on material properties. The paper presents initial results of a conducted test of the mechanical properties of the F75 Co-Cr dental alloy used with selective laser melting.Dana istraživanja se odnose na primjenljivost tehnike selektivnog laserskog topljenja (SLT) u proizvodnji djelomičnih zubnih proteza, pri čemu je posebna pažnja usmjerena na svojstva materijala. Rad prikazuje inicijalne rezultate sprovedenog testiranja mehaničkih svojstva F75 Co-Cr dentalne legure za primjenu kod selektivnog laserskog topljenja

Increased blood pressure in adult offspring of families with Balkan Endemic Nephropathy: a prospective study

BACKGROUND: Previous studies have linked smaller kidney dimensions to increased blood pressure. However, patients with Balkan Endemic Nephropathy (BEN), whose kidneys shrink during the course of the disease, do not manifest increased blood pressure. The authors evaluated the relationship between kidney cortex width, kidney length, and blood pressure in the offspring of BEN patients and controls. METHODS: 102 offspring of BEN patients and 99 control offspring of non-BEN hospital patients in the Vratza District, Bulgaria, were enrolled in a prospective study and examined twice (2003/04 and 2004/05). Kidney dimensions were determined using ultrasound, blood pressure was measured, and medical information was collected. The parental disease of BEN was categorized into three groups: mother, father, or both parents. Repeated measurements were analyzed with mixed regression models. RESULTS: In all participants, a decrease in minimal kidney cortex width of 1 mm was related to an increase in systolic blood pressure of 1.4 mm Hg (p = 0.005). There was no association between kidney length and blood pressure. A maternal history of BEN was associated with an increase in systolic blood pressure of 6.7 mm Hg (p = 0.03); paternal BEN, +3.2 mm Hg (p = 0.35); or both parents affected, +9.9 mm Hg (p = 0.002). There was a similar relation of kidney cortex width and parental history of BEN with pulse pressure; however, no association with diastolic blood pressure was found. CONCLUSION: In BEN and control offspring, a smaller kidney cortex width predisposed to higher blood pressure. Unexpectedly, a maternal history of BEN was associated with average increased systolic blood pressure in offspring

Metals and kidney markers in adult offspring of endemic nephropathy patients and controls: a two-year follow-up study

Abstract Background The etiology of Balkan Endemic Nephropathy, (BEN), a tubulointerstitial kidney disease, is unknown. Although this disease is endemic in rural areas of Bosnia, Bulgaria, Croatia, Romania, and Serbia, similar manifestations are reported to occur in other regions, for instance Tunisia and Sri Lanka. A number of explanations have been stated including lignites, aristolochic acid, ochratoxin A, metals, and metalloids. Etiologic claims are often based on one or a few studies without sound scientific evidence. In this systematic study, we tested whether exposures to metals (cadmium and lead) and metalloids (arsenic and selenium) are related to Balkan Endemic Nephropathy. Methods In 2003/04 we recruited 102 adults whose parents had BEN and who resided in one of three communities (Vratza, Bistretz, or Beli Izvor, Bulgaria). A control group comprised of 99 adults having non-BEN hospitalized parents was enrolled in the study during the same time. We conducted face-to-face interviews, ultrasound kidney measurements, and determined kidney function in two consecutive investigations (2003/04 and 2004/05). Metals and metalloids were measured in urine and blood samples. To assess the agreement between these consecutive measurements, we calculated intraclass correlation coefficients. Repeated measurement data were analyzed using mixed models. Results We found that cadmium and arsenic were associated with neither kidney size nor function. Lead had a significant but negligible effect on creatinine clearance. Selenium showed a weak but significant negative association with two of the four kidney parameters, namely creatinine clearance and β2-microglobulin. It was positively related to kidney length. These associations were not restricted to the offspring of BEN patients. Adding credence to these findings are reports showing comparable kidney effects in animals exposed to selenium. Conclusion The findings of this 2-year follow-up study indicate that metals and metalloids do not play a role in the etiology of Balkan Endemic Nephropathy. Against the assumption in the literature, selenium was not protective but a risk factor. Since comparable associations were observed in animals, future studies are needed to explore whether selenium may have adverse renal effects in humans.</p

An Introduction to Sphingolipid Metabolism and Analysis by New Technologies

Sphingolipids (SP) are a complex class of molecules found in essentially all eukaryotes and some prokaryotes and viruses where they influence membrane structure, intracellular signaling, and interactions with the extracellular environment. Because of the combinatorial nature of their biosynthesis, there are thousands of SP subspecies varying in the lipid backbones and complex phospho- and glycoheadgroups. Therefore, comprehensive or “sphingolipidomic” analyses (structure-specific, quantitative analyses of all SP, or at least all members of a critical subset) are needed to know which and how much of these subspecies are present in a system as a step toward understanding their functions. Mass spectrometry and related novel techniques are able to quantify a small fraction, but nonetheless a substantial number, of SP and are beginning to provide information about their localization. This review summarizes the basic metabolism of SP and state-of-art mass spectrometric techniques that are producing insights into SP structure, metabolism, functions, and some of the dysfunctions of relevance to neuromedicine

Characterisation of the cancer-associated glucocorticoid system:key role of 11β-hydroxysteroid dehydrogenase type 2

Background:Recent studies have shown that production of cortisol not only takes place in several non-adrenal peripheral tissues such as epithelial cells but, also, the local inter-conversion between cortisone and cortisol is regulated by the 11β-hydroxysteroid dehydrogenases (11β-HSDs). However, little is known about the activity of this non-adrenal glucocorticoid system in cancers.Methods:The presence of a functioning glucocorticoid system was assessed in human skin squamous cell carcinoma (SCC) and melanoma and further, in 16 epithelial cell lines from 8 different tissue types using ELISA, western blotting and immunofluorescence. 11β-HSD2 was inhibited both pharmacologically and by siRNA technology. Naïve CD8 + T cells were used to test the paracrine effects of cancer-derived cortisol on the immune system in vitro. Functional assays included cell-cell adhesion and cohesion in two-and three-dimensional models. Immunohistochemical data of 11β-HSD expression were generated using tissue microarrays of 40 cases of human SCCs as well as a database featuring 315 cancer cases from 15 different tissues.Results:We show that cortisol production is a common feature of malignant cells and has paracrine functions. Cortisol production correlated with the magnitude of glucocorticoid receptor (GR)-dependent inhibition of tumour-specific CD8 + T cells in vitro. 11β-HSDs were detectable in human skin SCCs and melanoma. Analyses of publicly available protein expression data of 11β-HSDs demonstrated that 11β-HSD1 and-HSD2 were dysregulated in the majority (73%) of malignancies. Pharmacological manipulation of 11β-HSD2 activity by 18β-glycyrrhetinic acid (GA) and silencing by specific siRNAs modulated the bioavailability of cortisol. Cortisol also acted in an autocrine manner and promoted cell invasion in vitro and cell-cell adhesion and cohesion in two-and three-dimensional models. Immunohistochemical analyses using tissue microarrays showed that expression of 11β-HSD2 was significantly reduced in human SCCs of the skin.Conclusions:The results demonstrate evidence of a cancer-associated glucocorticoid system and show for the first time, the functional significance of cancer-derived cortisol in tumour progression

Sharp integral inequalities based on general Euler two-point formulae

We consider a family of two-point quadrature formulae, using some Euler-type identities. A number of inequalities, for functions whose derivatives are either functions of bounded variation, Lipschitzian functions or R-integrable functions, are proved

Modelling of dynamic compliance of fixture/workpiece interface

In this paper, the compliance of interface between fixture elements and workpiece is theoretically and experimentally investigated. The proposed theoretical model allows modelling of the behaviour of all kinds of interfaces between fixture elements and workpiece, under arbitrary dynamic loads. Workpiece displacement relative to fixture element was determined by analytical solution of the Lagrange differential equations of motion. Interface stiffness and damping coefficient were determined experimentally. The results of experimental investigation confirm the claims of theoretical model. (Received in April 2013, accepted July 2013. This paper was with the authors 1 month for revision.)

Modelling of micro-turning process based on constant cutting force

In this research, an evaluation of the external transverse micro-turning with conventional cutting inserts was performed with a constant cutting force in a dry environment. During machining, the number of revolutions, machining time and cutting forces was varied. Before and after machining, the diameter of the workpiece, circularity and the roughness of the machined surface was measured. The obtained results indicate that with increasing number of revolutions, time and cutting force, the cutting depth increases. The results show that this type of machining can achieve very small cutting depths and reduce circularity deviation and roughness of the machined surface. Based on the experimental results, the modelling of the artificial neural network (ANN) was performed which reliably predicted the change in diameter, cylindricity, and roughness after micro-turning operation, with a mean percentage error smaller than 3 %. It can be concluded that the application of ANN is adequate during the machining process with the constant cutting force, since the output parameters can be predicted with small error, while also reducing effort and costs

Floristic Composition as a Parameter of the Quality of the Grassland Type \u3cem\u3eFestucetum Vallesacae\u3c/em\u3e in Thestara Planina Hilly-Mountainous Region of Serbia

With the increase of sea level and changes of climatic conditions, the possibilities for growing cultivated forages decreases. Therefore natural grasslands will become more important in relation to livestock nutrition. This will increase the importance of the nutritive value of these natural grasslands that have very diverse and dynamic floristic composition. The quality of the grassland depends on species categorised as grasses, legumes and other species. Other species were often regarded as harmful in regard to quality, however, they often contain many medicinal and stimulating substances that may have beneficial effects on animals and on the quality of animal products (Djordjevic-Milosevic, 1997). Conversely, there are also weed and harmful species among grasses and legumes. however, among species from other families there are also useful species. To provide nutrition of livestock from quality grasslands melioration measures are necessary. This paper reports on the composition of grasslands in Stara Planina and provides information on the proportion of useful species

Modelling and prediction of surface roughness in cnc turning process using neural networks

© 2020, Strojarski Facultet. All rights reserved. The paper presents an approach to solving the problem of modelling and prediction of surface roughness in CNC turning process. In order to solve this problem an experiment was designed. Samples for experimental part of investigation were of dimensions Φ30 × 350 mm, and the sample material was GJS 500-7. Six cutting inserts were used for the designed experiment as well as variations of cutting speed, feed and depth of cut on CNC lathe DMG Moriseiki-CTX 310 Ecoline. After the conducted experiment, surface roughness of each sample was measured and a data set of 750 instances was formed. For data analysis, the Back-Propagation Neural Network (BPNN) algorithm was used. In modelling different BPNN architectures with characteristic features the results of RMS (Root Mean Square) error were controlled. Specially analysed were the RMS errors realised by different number of neurons in hidden layers. For the BPNN architecture with one hidden layer the architecture (4 – 8-1) was adopted with RMS error of 3,37%. In modelling the BPNN architecture with two hidden layers, a considerable amount of architectures was investigated. The adopted architecture with two hidden layers (4-2-10-1) generated the RMS error of 2,26%. The investigation was also directed at the size of the data set and controlling the level of RMS error