Utjecaj aluminija i titana na mikrostrukturu i kvalitetu željeznih odljevaka s udjelom vermikularnog grafita

The contribution is aimed at study of influence of chemical composition of compacted graphite cast iron (CGI) on microstructure and surface quality of castings, particularly on the occurrence of pinholes. It has been found out that aluminium and titanium in CGI effect the formation of this defect in castings. Aluminium content in the range of 0,02 up to 0,1 % is critical. Increased occurrence of pinholes was also determined with Ti contents above 0,1%. On the same set of experimental castings it has been found out that increased contents of those elements on the other hand support the crystallization of compacted graphite. But the utilization of that method for control of CGI microstructure is limited with a possibility of formation of surface defects in castings – pinholes, but also coldshuts and shrinkage cavities.Rad istražuje utjecaj kemijskog sastava odljevaka čelika s udjelom vermikularnog grafita na njihovu mikrostrukturu i površinska svojstva, osobito pri pojavi poroznosti. Utvrđen je utjecaj aluminija i titana na nastanak pora u odljevcima. Kritičan je udio aluminija između 0,02 i 0,1%. Također, pore su učestalije pri udjelu titana iznad 0,1%. Na istim uzorcima eksperimentalnih odljevaka utvrđeno je i kako povišeni udjeli ovih elemenata istodobno potpomažu kristalizaciju vermikulanog grafita. Primjena metode za kontrolu mikrostrukture odljevaka s vermikularnim grafitom (CGI) limitirana je, uz mogućnost pojave površinskih nedostataka odljevaka u vidu pora, hladnih zavara i šupljina nastalih skupljanjem

Spinal anaesthesia in a patient with Takayasu's disease

We report the successful anaesthetic management of therapeutic abortion under spinal anaesthesia in a 32-yr-old woman with Takayasu's disease. The pathology and pathophysiology of this syndrome and their impact on anaesthesia are discussed. (Br. J. Anaesth. 1994; 72: 129-132

Parents and Pediatric Weight Management Attrition: Experiences and Recommendations

Background: One of the most frequently cited challenges faced by pediatric weight management programs/clinics is attrition, with many studies reporting rates greater than 50%. Few studies have evaluated parental perspectives on recommendations for weight-management treatment enhancement. The aim of this study was to elicit perspectives on areas for improvement, discussions with staff about discontinuation, and potentially modifiable aspects of attrition from parents who prematurely discontinued stage 3 pediatric weight management treatment. Methods: This study was performed as a semistructured interview as part of a telephone survey assessing reasons for attrition. Results: Interviews were performed with 147 parents of children who attended programs/clinics at 13 children's hospitals participating in the National Association of Children's Hospitals and Related Institutions (now Children's Hospital Association) FOCUS on a Fitter Future II collaborative. The majority of parents (65%) denied talking to staff about their decisions to stop coming. When describing what could have been done to retain families, parents most frequently discussed changing logistics (e.g., hours and locations). Parents described changes in logistics and components (i.e., nutrition education, exercise, and behavior education/support) when asked what would work best for their family for pediatric weight management. Conclusions: Parental responses appeared to express frustration about flexibility with appointment times and treatment locations. The most frequently desired components were those traditionally offered by stage 3 pediatric weight management programs/clinics, and this may suggest a need for treatment delivery of these components to be more individualized. Additional discussion with families about their desire to discontinue treatment may provide a timely opportunity to address this need.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140333/1/chi.2013.0069.pd

Application of thermodynamic calculations in the research of cast irons structure

The contribution summarises the results of application of thermodynamic calculation obtained from oxygen activities measurements in cast irons with various type of graphite microstructure. The results were used to find the relationship between natural logarithm of oxygen activities and reverse value of thermodynamic temperature 1/T.From obtained regression line the calculation of oxygen activities value for significant temperature of molten metal was achieved. Each material has its proper typical oxygen activities range for analysing and controlling graphite quality. Practical implication was successfully tested in a Czech foundry producing centrifugally poured cast iron rolls designed for hot strip mills with spheroidal graphite iron core

Immunologic markers of progression to acquired immunodeficiency syndrome are time-dependent and illness-specific

Krämer A, Biggar RJ, Hampl H, et al. Immunologic markers of progression to acquired immunodeficiency syndrome are time-dependent and illness-specific. American Journal of Epidemiology. 1992;136(1):71-80.Since prevalent cohorts may be biased by the duration of human immunodeficiency virus (HIV) infection (onset bias), it is useful to assess the potential predictive value of markers in incident cohorts of HIV-positive subjects for whom the date of seroconversion is known or can reliably be estimated. Of 131 homosexual men with HIV-1 seroconversion from New York City and Washington, DC, who were evaluated annually beginning in 1982, 60 developed acquired immunodeficiency syndrome (AIDS) by the end of 1989. The prognostic significance of immunologic markers (proportion of CD4+ T-lymphocytes, neopterin, ß2-microglobulin, serum interferon, and anti-p24 antibody) and of a virologic marker (HIV p24 antigen) was determined using measurements made at defined time intervals after the known or estimated date of HIV seroconversion. When measurements made 3 years after seroconversion were used, all markers except anti-p24 antibody were found to be significant estimators of AIDS risk in univariate analyses. In multivariate Cox regression modeling, the maximum information was obtained by including neopterin, interferon, and the CD4+ T-lymphocyte proportion. The predictive value of markers after HIV seroconversion could change considerably from one interval to another. Elevated levels of ß2-microglobulin and neopterin significantly predicted the development of Kaposi‘s sarcoma. These two markers were highly correlated (r=0. 74). The authors conclude that immunologic markers can be important for an HIV staging system for estimating prognosis and facilitating early therapeutic intervention in HIV-positive patients

Multivariate calibration approach for quantitative determination of cell-line cross contamination by intact cell mass spectrometry and artificial neural networks

Cross-contamination of eukaryotic cell lines used in biomedical research represents a highly relevant problem. Analysis of repetitive DNA sequences, such as Short Tandem Repeats (STR), or Simple Sequence Repeats (SSR), is a widely accepted, simple, and commercially available technique to authenticate cell lines. However, it provides only qualitative information that depends on the extent of reference databases for interpretation. In this work, we developed and validated a rapid and routinely applicable method for evaluation of cell culture cross-contamination levels based on mass spectrometric fingerprints of intact mammalian cells coupled with artificial neural networks (ANNs). We used human embryonic stem cells (hESCs) contaminated by either mouse embryonic stem cells (mESCs) or mouse embryonic fibroblasts (MEFs) as a model. We determined the contamination level using a mass spectra database of known calibration mixtures that served as training input for an ANN. The ANN was then capable of correct quantification of the level of contamination of hESCs by mESCs or MEFs. We demonstrate that MS analysis, when linked to proper mathematical instruments, is a tangible tool for unraveling and quantifying heterogeneity in cell cultures. The analysis is applicable in routine scenarios for cell authentication and/or cell phenotyping in general