Cyano-modified silica-gel as a sorbent in planar chromatography

Cilj ove disertacije bio je ispitivanje karakteristika i mogućnosti primene cijanomodifikovanog silika-gela kao sorbenta umerene polarnosti za odvajanja kako u normalno-faznoj tako i u reverzno-faznoj planarnoj hromatografiji. Planarna, odnosno tankoslojna hromatografija kao podvrsta tečne hromatografije je odabrana pre svega zbog svoje jednostavnosti, brzine i efikasnosti. Cijano-modifikovani silika-gel, zahvaljujući prisustvu različitih površinskih aktivnih centara (cijano-grupa i alkil-nizova unetih modifikacijom kao i nemodifikovanih silanolnih grupa), može da ostvaruje nekoliko vrsta specifičnih interakcija sa odvajanim supstancama. Stoga je u okviru ovog rada detaljno proučavano retenciono ponašanje različitih klasa neorganskih i organskih supstanci na tankom sloju pomenutog sorbenta za koje je pretpostavljeno da bi mogle specifično da interaguju pre svega sa cijano-grupama sorbenta i svojim ponašanjem ukažu na učešće ovih aktivnih centara u procesu hromatografskog razdvajanja. U tom smislu, posebna pažnja je posvećena ispitivanju sorbenada koji sadrže aromatične delove strukture, kao što su mešoviti (b-diketonato) i (b-ketoiminato) kompleksi prelaznih metala sa različitim brojem fenil-grupa u molekulu, različiti derivati fenola, kao i triazinski derivati i fenoksikarboksilne kiseline, primenom različitih reverezno-faznih i normalno-faznih hromatografskih sistema. U istom cilju poreñeni su rezultati ispitivanja hromatografskog ponašanja istih analita u različitim hromatografskim sistemima, odnosno na tankim slojevima sorbenata sa definisanim površinskim aktivnim sorpcionim centrima. Pored toga, jedan od ciljeva istraživanja bio je i proširenje primene cijanomodifikovanog silika-gela kao specifičnog sorbenta za hromatografiju hidrofilnih interakcija (Hydrophilic Interaction Liquid Chromatography, HILIC) kao relativno novu hromatografsku tehniku. Takođe, cilj ovoga rada bio je da se, osim teorijskog, istakne i praktičan značaj izvedenih hromatografskih odvajanja, pa je stoga u okviru RP hromatografskih uslova proučavana primenljivost cijano-modifikovanog silika-gela kao sorbenta u hromatografskim sistemima koji se koriste za modelovanje zemljište-voda podeonih koeficijenata normiranih na sadržaj organskog ugljenika (logKOC) kao jednim od ključnih parametara koji odreñuju sudbinu organskih jedinjenja u životnoj sredini.The aim of this thesis is testing features and possibilities of using cyanomodified silica-gel as a sorbent of medium polarity for separation in both normal-phase and reversed-phase planar chromatography. Planar i.e. thin-layer chromatography as subgroup of liquid chromatography was chosen due to its simplicity, rapidity and efficiency. Cyano-modified silica-gel, due to the presence of various surface-area active centers (cyano-groups and alkyl-chains inserted by modification as well as nonmodified silanol groups), may achieve several types of specific interactions with separated substances. Thus, within this thesis we thoroughly carried out testing of retention behaviour of different inorganic and organic substances on a thin layer of mentioned sorbent that we assume may have specific interaction mainly with cyano groups of sorbent and, consequently indicate the participation of these active centers in the process of chromatographic separation. In that sense, special attention was paid to investigating sorbends which contain aromatic structure parts, such as mixed (β-diketonate) and (β-ketoiminato) complexes of transition metals with different number of phenyl groups in molecule, various derivatives of phenols as well as triazines and phenoxycarboxylic acids by applying different normal-phase and reversed-phase chromatographic systems. With the same aim, we compared chromatographic behaviour of the same analytes in different chromatographic systems, i.e. on thin layers of sorbents with defined surface active sorption centers. Apart from that, one of the aims of this research was to enhance the use of cyano-modified silica-gel as specific sorbent for hydrophilic interaction liquid chromatography (HILIC) as a relatively new chromatographic technique. In addition, the aim of this thesis is to emphasize the practical significance of studied chromatographic besides the theoretical one. Thus, within reversed-phase chromatographic conditions, we examined the use of cyano-modified silica-gel as sorbent for modeling of soil-water partition coefficients normalized to the organic carbon content (logKoc) as one of the key parameters that define the destiny of organic substances in the environment

Influence of the damage level during quenching on thermal shock behavior of low cement castable

In the recent decades, the use of unshaped monolithic refractories has been increasing greatly because of their significant advantages over other shaped refractory bricks of the same class. A low cement high alumina castable was synthetised and sintered at 1300°C in order to investigate thermal and mechanical properties, as well as thermal shock behavior. The water quench test was applied as an experimental method for thermal stability testing. Modification of the water quench test was performed by additional monitoring of the samples behavior during the water quench test such as implementation of image analysis and ultrasonic measurements. The image analysis program was applied on samples in order to measure the level of surface damage before and during the water quench test. Ultrasonic measurements were performed with the aim to measure the Young modulus of elasticity during the testing. Strength deterioration of the samples was calculated by the model based on ultrasonic velocity changes during the water quench test. The influence of monitoring the damage level before and during the quench experiment and its influence on thermal shock behavior will be discussed

Expression and biochemical and functional characterization of R-MC 17 antigen in rat

Razvoj T limfocita u timusu je rezultat niza dvosmernih komunikacija između timocita i ćelija mikrosredine, posredovanih pretežno adhezivnim molekulima. U Institutu za medicinska istaživanja VMA je napravljen panel monoklonskih antitela (mAt) R-MC serije, koja prepoznaju timusne epitelne ćelije (TEC). Cilj ovog rada je bio biohemijska, imunohistohemijska i funkcionalna karakterizacija antigena koga detektuje R-MC 17 mAt. Ovo mAt detektuje antigen od 205 kDa u timusu pacova. Na osnovu poređenja biohemijskih karakteristika anti-DEC 205 mAt (HD83) i unakrsne imunoprecipitacije antigena iz lizata timusa pacova pomoću ova dva mAt zaključeno je da R-MC 17 mAt detektuje pacovski DEC-205 molekul. R-MC 17 antigen je jako ispoljen na kortikalnim TEC, medularnim timusnim dendritskim ćelijama (TDC), DC u parakorteksu i interfolikularnim zonama limfnog čvora i DC u periarteriolarnom limfnom omotaču slezine. Slaba imunoreaktivnost je detektovana na limfocitima u folikulima limfnog čvora i slezine i makrofagama u crvenoj pulpi slezine. Takođe, ekspresija DEC-205 molekula je detektovana na oko 40% ćelija TEC linije sa karakteristikama ćelija „dadilja“. R-MC 17 mAt podstiče vezivanje i emperipoezu timocita od strane ove epitelne linije. Istovremeno, ekspresija R-MC 17 antigena je podjednaka na subpopulacijama TDC pacova (CD11b+ i CD11b-), i ne menja se pod uticajem GM-CSF-a. Oba anti-DEC 205 mAt (R-MC 17 mAt i HD83 mAt) stimulišu apoptozu timocita u kokulturi sa TDC i ovaj proces je povezan sa povećanim vezivanjem timocita za TDC. R-MC 17 mAt inhibira proliferaciju singenih timocita i alogenih T limfocita pacova u kokulturi sa TDC u prisustvu anti-TCR (R7.3) mAt. Intratimusna aplikacija R-MC 17 mAt dovodi do smanjenja celularnosti timusa pacova što je povezano sa indukcijom apoptoze timocita. Fenotipska analiza subpopulacija timocita nakon intratimusne aplikacije R-MC 17 mAt pokazuje smanjenje ukupnog broja CD4+CD8+ i CD4+CD8-, a povećanje ukupnog broja CD4-CD8+ timocita, dok je ukupan broj zrelih CD5+TCRjako+ timocita nepromenjen. Sveukupno, ovi rezultati prvi put opisuju potencijalnu funkciju R-MC 17 antigena u timusu.Opisani mehanizmi mogu biti povezani sa procesima intratimusne diferencijacije timocita i prezentacije vi autoantigena u timusu od strane kortikalnih TEC i medularnih TDC, a što u krajnjem ishodu ima uticaj na procese selekcije (delecije autoreaktivnih klonova timocita).Intrathymic development of T lymphocyte is mainly governed by an array of bidirectional interactions between thymocytes and thymic microenvironment, which are mostly provided by the adhesive molecules. The monoclonal antibody (mAb) panel of R-MC series, designed against thymic epithelial cells (TEC), was developed at the Institute of medical research (MMA). The aim of this doctoral thesis was focused on biochemical, immunohistochemical and functional characterization of the R-MC 17 antigen, detected by R-MC 17 mAb. R-MC 17 mAb recognizes the 205 kDa molecule expressed in the rat thymus. Based on similarity in biochemical features with an anti- DEC-205 mAb (HD83), and cross-immunoprecipitation of antigen from the thymic lysate with these two mAbs, R-MC 17 was considered to be the antibody specific for the rat DEC-205 molecule. Cortical TEC, medullary thymic dendritic cells (TDC), lymph node dendritic cells (DC) in paracortex and interfollicular zones, and spleen paraarteriolar-lymphoid sheaths DC, are highly positive with R-MC 17. Lymphocytes in lymph node and spleen follicles and red pulp macrophages in spleen, show weak R-MC 17 reactivity. About 40% of TEC-line cells with nursing characteristics express R-MC 17 antigen as well. R-MC 17 stimulates thymocyte binding and emperipoesis displayed by this cell line. Concomitantly, R-MC 17 antigen is equally expressed on two rat TDC subpopulations (CD11b+ and CD11b-), and cultivation with GM-CSF has no effect. RMC 17, as well as HD83, stimulates thymocyte apoptosis in co-culture with TDC, and this process is associated with the increased binding of thymocytes to TDC. R-MC 17 mAb inhibits proliferation of syngeneic thymocytes and allogeneic T lymphocytes in anti-TCR (R7.3)-stimulated cocultures with TDC. Intrathymic injection of R-MC 17 mAb decreases thymic cellularity, which was related to the induction of thymocyte apoptosis. Phenotypic analysis of thymocyte populations after intrathymic application of R-MC 17 mAb, indicates decrease of the absolute number of CD4+CD8+ and CD4+CD8- , and increase of CD4-CD8+ thymocyte subpopulations, while the absolute number of mature CD5+TCRhigh thymocytes stays unchanged. Taken together, these results show, for the first time, a potential function of R-MC 17 antigen in rat thymus. Mechanisms viii described, are potentially involved in the processes of intrathymic differentiation and the presentation of autoantigen in the thymus by the cortical TEC and medullary TDC, having final implications in the processes of thymic selection (deletion of autoreactive thymocytes)

Digital Manufacturing as a basis for the development of the Industry 4.0 model

The digital manufacturing (DM) is base for Industry 4.0, that have following dimensions: (i) digital manufacturing based on advanced digital-oriented technologies, (ii) smart products (advanced production mode and new characteristics), and (iii) smart supply - chain (procurement of raw materials and delivery of finished products). Bidirectional exchange of information in collaborative production, using it exchange also for digital platforms of design of the innovative products. This paper presents developed model of Serbian digital factory with selected examples, specifically for the Manufacturing Execution System (MES) area

Digital Manufacturing as a basis for the development of the Industry 4.0 model

The digital manufacturing (DM) is base for Industry 4.0, that have following dimensions: (i) digital manufacturing based on advanced digital-oriented technologies, (ii) smart products (advanced production mode and new characteristics), and (iii) smart supply - chain (procurement of raw materials and delivery of finished products). Bidirectional exchange of information in collaborative production, using it exchange also for digital platforms of design of the innovative products. This paper presents developed model of Serbian digital factory with selected examples, specifically for the Manufacturing Execution System (MES) area

Thermal shock resistance of ceramic fibre composites characterized by non-destructive methods

Alumina based ceramic fibres and alumina based ceramic were used to produce composite material. Behaviour of composite ceramics after thermal shock treatments was investigated. Thermal shock of the samples was evaluated using water quench test. Surface deterioration level of samples was monitored by image analysis before and after a number of quenching cycles. Ultrasonic measurements were done on samples after quench tests. Dynamic Young modulus of elasticity and strength degradation were calculated using measured values of ultrasonic velocities. Strengths deterioration was calculated using the non-destructive measurements and correlated to degradation of surface area and number of quenches. The addition of small amount of ceramic fibres improves the strengths and diminishes the loss of mechanical properties of samples during thermal shock experiments

Dental Anxiety in Relation to Emotional and Behavioral Problems in Croatian Adolescents

The investigation was performed on 113 adolescents in the age between 15 and 18 years (63 boys, 50 girls). Corah Dental Anxiety Scale (CDAS) and Children’s Fear Survey Schedule – Dental Subscale (CFSS-DS) were used for evaluation of dental fear and Child Medical Fear Questionnaire (CMFQ) for evaluation of the fear of medical treatment. Achenbach Youth Self Report questionnaire (YSR) was used for evaluation of emotional and behavioral problems. The tests were filled in by children. The aim of the study was to evaluate the level of dental anxiety in adolescents and to assess a cause – consequence relationship between dental anxiety and emotional and behavioral problems in adolescents. The results of CDAS, CFSS-DS and CMFQ tests showed that dental anxiety scores and the total internalizing problems were higher in girls. Girls displayed more physical problems (p<0.001) and were more prone to anxiety/depression disorders (p<0.05). Both boys and girls were more agressive, more prone to delinquent behaviour and had more externalizing problems in comparison with the average values obtained for the Croatian population. Significant correlation coefficients for boys were calculated for age and anxiety/depression, and delinquent behaviour and aggression (p<0.05). Significant correlations were observed between physical problems and dental anxiety measured by the CFSS-DS test (p<0.01), and between physical problems and the total internalizing problems (p<0.05). In girls, the CMFQ scores showed significant correlations between dental anxiety and physical problems (p<0.05), and anxiety/ depression (p<0.01) and the total internalizing and externalizing problems (p<0.05). Significant correlations were calculated for age and the total internalizing and externalizing problems for boys (p<0.05). According to the results of both CDAS and CMFQ tests, anxiety in girls showed significant correlations with delinquent behaviour (p<0.01). CDAS scores for girls showed significant correlations with aggression (p<0.05) and the total externalizing problems (p<0.01)

SOIL BIOGENICITY IN THE RHIZOSPHERE OF DIFFERENT WHEAT GENOTYPES UNDER THE IMPACT OF FERTILIZATION TREATMENT

The rhizosphere is a dynamic environment in which many parameters may influence biogenicity. The important factors determining the microbial community in the rhizosphere are plant and soil nutrient supply. The aim of this paper was to determine the abundance of basic microbiological groups in the rhizosphere of four wheat subspecies, in three fertilization treatments in the organic farming system. A field experiment was conducted using a randomized complete block design with four replicates. It was carried out on the leached chernozem soil type. There was significant variability in the abundance of the studied physiological groups of microorganisms between the wheat subspecies, as well as between the fertilization treatments. The rhizosphere of common wheat had the greatest abundance of fungi (24.37 x 103 g-1). The rhizosphere of compactum wheat had the largest abundance of oligonitrophilic bacteria (361.47 x 105 g-1) and amonificators (119.27 x 105 g-1). There were no significant differences in the abundance of actinomycetes between the cultivars of common, compactum and durum wheat, but their lowest number was found in the spelt wheat cultivar (11.25 x 103 g-1). The combined application of biofertilizer and organic fertilizer resulted in a significantly greater abundance of amonificators (56.6%), fungi (28.2%) and oligonitrophiles (14.6%) than in the control treatment. The results show that the crop variety and application of appropriate fertilizer formulations can influence the abundance of the studied groups of microorganisms. This is particularly the case in organic farming, which relies completely on natural resources and processes. Copyright © 2022 Jialin Yuan et al

Lunar Gravitational-Wave Detection

A new era of lunar exploration has begun bringing immense opportunities for science as well. It has been proposed to deploy a new generation of observatories on the lunar surface for deep studies of our Universe. This includes radio antennas, which would be protected on the far side of the Moon from terrestrial radio interference, and gravitational-wave (GW) detectors, which would profit from the extremely low level of seismic disturbances on the Moon. In recent years, novel concepts have been proposed for lunar GW detectors based on long-baseline laser interferometry or on compact sensors measuring the lunar surface vibrations caused by GWs. In this article, we review the concepts and science opportunities for such instruments on the Moon. In addition to promising breakthrough discoveries in astrophysics and cosmology, lunar GW detectors would also be formidable probes of the lunar internal structure and improve our understanding of the lunar geophysical environment