281 research outputs found
OdreÄivanje sadržaja fluorida u vodi za piÄe i Äajevima fluorid-selektivnom elektrodom
Potentiometric analysis of fluoride content (as F- ion) in solutions by using fluoride ion-selective electrode is simple, reliable and cheap. Very small concentrations of fluoride-ions (to 10-6 mol/dm3) can be determined by fluoride selective electrode, with regulation of ion strength of a solution and control of concentration of hydroxide ions and interfering ions of metals. The influence of pH and complexing ions of metals can be successfully regulated by the TISAB solution and by preserving pH value in the range from 5.00 to 7.00. The content of fluorides in the samples can be determined by the method of direct potentiometer, and in the case of very low concentration by standard addition method. In this paper it was analyzed the determination of fluoride ions concentration in bottled mineral waters and water from Belgrade plumbing in two Belgrade districts (Palilula and Novi Beograd) and in tea, by using the fluoride selective electrode. It was determined that the content of fluoride ions in bottled mineral water significantly differs from values given on declaration, and that content of fluoride ions varies over a period of time. The content of fluoride ions in water from plumbing in two Belgrade districts at the time of analysis was significantly increased and exceeded values given in Regulation for drinking water quality. The received results from the analysis of fluorides in teas show that fluorides exist in teas in different concentrations. There are also differences between the same kinds of tea, which is noted with mint (Mentha piperitae folium), as a consequence of differences between soils where it was planted. As taking of fluorides, according to World Health Organisation recommendation (WHO), is limited in the range from 2 to 4 mg per day, it is necessary to give the content of fluorides on all products that are used in human consumption.Potenciometrijsko odreÄivanje sadržaja fluorida (kao F-jon) u rastvorima upotrebom fluoridne jon-selektivne elektrode je jednostavno, pouzdano i jeftino. Fluorid-selektivnom elektrodom mogu se odrediti veoma niske koncentracije fluorid-jona (do 10-6 mol/dm3), uz regulisanje jonske jaÄine rastvora i kontrolisanje koncentracije hidroksid-jona i interferirajuÄih jona metala. Uticaj pH i kompleksirajuÄih jona metala može se uspeÅ”no regulisati rastvorom TISABa i održavanjem pH vrednosti u oblasti od 5,00 do 7,00. Sadržaj fluorida u uzorcima može se odrediti metodom direktne potenciometrije, a u sluÄaju veoma niskih koncentracije, metodom standardnog dodatka. U radu je vrÅ”eno odreÄivanje koncentracije F--jona u flaÅ”iranim mineralnim vodama ('VujiÄ voda', 'Rosa', 'Duboka', 'Voda-voda', 'Aqua viva', 'Knjaz MiloÅ”') i vodi iz beogradskog vodovoda sa dve beogradske opÅ”tine (Palilula i Novi Beograd) i u Äajevima (Divlja nana (Mentha piperitae folium), Äaj od žalfije (Salviae officinalis), Äaj od kantariona (Hypericum perforatum), 'DomaÄa nana' (Mentha piperita L.), Äaj od kamilice (Chamomillae flos)), upotrebom fluorid-selektivne elektrode. UoÄeno je da sadržaj fluorid-jona u flaÅ”iranim mineralnim vodama znatno odstupa od vrednosti koje su date na deklaraciji, ali i da sadržaj fluorid-jona varira tokom vremena. Sadržaj fluorid-jona u vodi iz vodovoda sa dve beogradske opÅ”tine, u vreme analiziranja je znatno poveÄan i premaÅ”uje vrednosti propisane Pravilnikom o kvalitetu vode za piÄe. Dobijeni rezultati ispitivanja fluorida u Äajevima ukazuju da se fluoridi nalaze u Äajevima u razliÄitim koncentracijama. Do razlike dolazi i meÄu istim vrstama Äaja, Å”to je zabeleženo kod nane (Mentha piperitae folium), Å”to je posledica pre svega zemljiÅ”ta na kojem je nana uzgajana. Kako je, saglasno preporukama Svetske zdravstvene organizacije (SZO), unoÅ”enje fluorida limitirano u opsegu 2 do 4 mg dnevno, na svim proizvodima koji se koriste u humanoj upotrebi potrebno je navesti i sadržaj fluorida
OdreÄivanje titracione kiselosti u belom vinu
The amount of titration acid in must is in the largest number of cases with in the range 5.0-8.0 g/dm3. Wines, as a rule, contain less acids than must, and according to Regulations, titratable acidity is in the range of 4.0-8.0 g/dm3 expressed in tartaric acid, because a part of tartaric acid is deposited in the form of salts (tartar or argol) during alcohol fermentation. For wines that contain less than 4 g/dm3 of titratable acids there arises a suspicion about their origin, that is, that during the preparation some illegal acts were done. Because of that, the aim of this paper is to determine titratable acidity in white wine, using standard methods of determination, which are compared with the results received by potentiometric titration using ion-selective electrode. According to the received results it can be seen that wine titration with indicator gives sufficient reliable values of wine titration acidity. However, as potentiometric titration at pH value 7.00 is more reliable and objective method, the values of titratable acids content in wine, expressed through tartaric acid, are given according to this result. The analysis of differential potentiometric curves shows that these curves can give us an answer to the question of the presence of a larger amount of other nonorganic substances, which have already existed in wine. However, none of the used methods gives absolutely reliable answer what substances are present in analysed samples.KoliÄina titracionih kiselina u Å”iri se, u najveÄem broju sluÄajeva, kreÄe izmeÄu 5 i 8 g/dm3. Vina, po pravilu, sadrže neÅ”to manje kiselina nego Å”ira, a prema Pravilniku, titraciona kiselost se kreÄe izmeÄu 4,0 i 8,0 g/dm3 izraženo u vinskoj kiselini, jer se deo vinske kiseline istaloži u obliku soli (streÅ”a) u toku alkoholne fermentacije. Za vina koja sadrže ispod 4 g/dm3 titracionih kiselina postoji sumnja u njihovo poreklo, tj. da su prilikom njihovog spravljanja vrÅ”ene nedozvoljene radnje. Zbog toga je cilj rada bio da se izvrÅ”i odreÄivanje titracione kiselosti u belom vinu, standardnim metodama odreÄivanja koje su uporeÄene sa rezultatima dobijenim potenciometrijskom titracijom uz jon-selektivnu elektrodu. Na osnovu dobijenih rezultata uoÄava se da titracija vina uz indikator daje dovoljno pouzdane vrednosti titracione kiselosti vina. MeÄutim, poÅ”to je potenciometrijska titracija, pri pH vrednosti 7,00, pouzdanija i objektivnija metoda, vrednosti za sadržaj titracionih kiselina u vinu, izraženih preko vinske kiseline, date su upravo na osnovu ovog rezultata. Analiza diferencijalnih potenciometrijskih krivih, ukazuje da ove krive mogu pružiti odgovor na pitanje o prisustvu veÄe koliÄine drugih neorganskih supstanci, koje se veÄ nalaze u vinu. MeÄutim, ni jedna od ispitivanih metoda ne daje dovoljno pouzdan odgovor koje supstance su prisutne u analiziranim uzorcima, veÄ odgovor na ovo pitanje može pružiti jedino metoda jonske hromatografije
Influence of Substrate and Screen Thread Count on Reproduction of Image Elements in Screen Printing
The printing plate and its characteristics in the conventional printing techniques
have a significant impact on print quality and image appearance. In screen printing,
a weave of screen mesh i.e. a number of threads per cm, is the most important
characteristic of the printing plate, hence the most relevant factor which defines
printing quality. Print quality itself is a complex term that includes desired colour
reproduction and satisfactory reproduction of image elements. In this paper focus
was centred upon the reproduction of text and basic image elements (lines and dot
structure) when printing on non-absorbent and absorbent substrates with different
screen thread counts. The image element analysis led to the conclusion that using
mesh with higher thread count does not significantly improve the reproduction of
image elements. However, it is a very important parameter for text reproduction
since low thread count may result in poor readability
Analiza antiapoptotskog proteina bcl-2 u skvamocelularnom karcinomu usne regije
Aim: The aim of this study was to analyze the presence of the anti-apoptotic protein bcl-2 in oral squamous cell carcinoma and determine its potential role in the development and progression of this type of tumor. Materials and methods: The expression of bcl-2 was determined in 28 paraffin blocks of oral squamous cell carcinoma using the immunohistochemical method. The percentage of the immuno-reactive cells in positively stained tumor regions was determined using the microscopic analysis and Ozaria software. Results: Positive immunohistochemical test was observed in 19 out of 28 samples (68%) as follows: in 11 samples there was a low (+), in four a moderate (++) and in the last four a high percentage (+++) of stained cells. In the group of patients at the low stage of the disease (T2), 50% of tumor samples showed bcl-2 protein expression whereas in the higher stages (T3 and T4) of positively stained samples, this percentage was 67%. There was a trend of an increasing number of cells with positive bcl-2 staining in the tumors of higher clinical stages but not the level of bcl-2 protein expression. Conclusion: Both parameters, the presence of bcl-2 staining and the percentage of cells with bcl-2 immunoexpression, may act as additional prognostic parameters that indicate an increased proliferative tumor potential.Cilj ove studije bio je analiza prisustva antiapoptotskog proteina bcl-2 u skvamocelularnom karcinomu usne regije i procena njegove eventualne uloge u razvoju i progresiji ove vrste tumora. Materijal i metode: Na uzorku od 28 parafinskih blokova skvamocelularnog karcinoma usne regije, imunohistohemijskom metodom ispitan je ekspresioni status bcl-2 proteina. Mikroskopskom analizom i primenom softvera- Ozaria odreÄen je procenat imunoreaktivnih Äelija u pozitivno obojenim tumorskim regijama. Rezultat: Pozitivnu imunohistohemijsku obojenost pokazalo je 19 od 28 uzoraka (68%) i to: 11 je bilo sa niskim (+), 4 sa srednjim (++) i 4 sa visokim procentom (+++) obojenih Äelija. U grupi pacijenata niskog stadijuma (T2) 50 % uzoraka tumora je pokazivalo ekspresiju bcl-2 proteina dok je u viÅ”im stadijumima (T3 i T4) pozitivnih uzoraka bilo 67%. Postojao je trend porasta broja Äelija sa pozitivnom bcl-2 obojenoÅ”Äu kod tumora u viÅ”im kliniÄkim stadijumima, ali ne i poveÄan nivo ekspresije bcl-2 proteina. ZakljuÄak: Oba parametra, prisustvo bcl-2 obojenosti i procenat Äelija sa bcl-2 imunoekspresijom, mogu predstavljati dopunske prognostiÄke parametre koji ukazuju na poveÄan proliferativni potencijal tumora
Usability of Calibrating Monitor for Soft Proof According to cie cam02 Colour Appearance Model
Colour appearance models describe viewing conditions and enable simulating appearance of colours under different illuminants and illumination levels according to human perception. Since it is possible to predict how colour would look like when different illuminants are used, colour appearance models are incorporated in some monitor profiling software. Owing to these software, tone reproduction curve can be defined by taking into consideration viewing condition in which display is observed. In this work assessment of cie cam02 colour appearance model usage at calibrating lcd monitor for soft proof was tested in order to determine which tone reproduction curve enables better reproduction of colour. Luminance level was kept constant, whereas tone reproduction curves determined by gamma values and by parameters of cie cam02 model were varied. Testing was conducted in case where physical print reference is observed under illuminant which has colour temperature according to iso standard for soft-proofing (d50) and also for illuminants d65. Based on the results of calibrations assessment, subjective and objective assessment of created profiles, as well as on the perceptual test carried out on human observers, differences in image display were defined and conclusions of the adequacy of cam02 usage at monitor calibration for each of the viewing conditions reached
Implementation of the next generation sequencing (ngs) methods in early diagnosis of heritable diseases
U cilju rane dijagnostike i prevencije naslednih poremeÄaja, proteklih
decenija su na raspolaganju bile razliÄite metode. Analize genetiÄkog materijala
su se kretale od klasiÄne citogenetiÄke obrade kariotipa radi uoÄavanja
numeriÄkih i strukturnih aberacija hromozoma, do najfinijih ispitivanja za
detektuju genskih mutacija na molekularnom nivou. Poslednjih godina razvijaju
se potpuno nove metode za brzu, efikasnu i dostupnu analizu naslednog
materijala, koje su poznate kao ānext generation sequencingā (NGS)
ili nova generacija metoda za sekvenciranje DNK. Ove metode omoguÄavaju
ispitivanje ne samo pojedinaÄnih gena ili delova gena nego i veÄeg broja
segmenata, sve do kompletne nasledne osnove tj. Äitavog genoma Äoveka.
Primena ovakvog pristupa dovodi do prave tihe revolucije u medicinskoj
genetici i disciplinama sa kojima ona saraÄuje, nagoveÅ”tavajuÄi promenu
u konceptu dijagnostike naslednih poremeÄaja. U prenatalnoj dijagnostici
NGS je veÄ naÅ”la primenu u potpuno neinvazivnoj detekciji najÄeÅ”Äih hromozomskih
aberacija (Daunov, Edvardsov, Patau sindrom, aberacije polnih
hromozoma) analizom fetalnih Äelija prisutnih u krvi majke. Test NIFTY
veÄ je dostupan i trudnicama u naÅ”oj sredini. U postnatalnom periodu NGS
se koristi za ispitivanje odabranih panela gena, ili, po potrebi, Äitavog genoma/
egzoma, sve sa ciljem Ŕto efikasnije dijagnostike pre svega monogenskih,
ali i oligogenskih i poligenskih bolesti.
Predlaže se Äak da analiza kompletnog genoma postane deo neonatalnog
skriniga, ali za sada to nije prihvaÄeno. Nesumnjivo je da rezultati NGS
donose veliki napredak medicinsko ā genetiÄkoj praksi, ali i raÄaju nove
etiÄke dileme u oblasti rane detekcije naslednih poremeÄaja i intervencije
kod ovih stanja.In order to early diagnostics and prevention of hereditary disorders, past decades
have been brought different methods. Analysis of genetic material ranged from
classical cytogentic karyotype analysis for processing numerical and structural
chromosomalaberratios, by most sophisticated examination of manor gene mutation
on molecular level. In recent years develop completely new methods for rapid, efficient
and publicly available analysis of inheritance material, that are known as the ānextā
button generation sequencingā (NGS). These methods allow for examination not only
individual genes or parts of genes but also a larger number of segments, all up to complete
inherited basis i.e. the entire human genome research. Implementation of this approach
leads to genuine silent revolution in medical genetics and disciplines with which it cooperate,
suggesting a change in the concept of heritage disorders diagnosing. In prenatal
diagnostics NGS has already found application in completely noninvsive detection
of chromosomal aberrations (Down, Edwards, Patau syndrome, sex chromosomes
aberration) by analysis of fetal cells present in motherās blood. Such tests (i.e. NIFTY)
are already available and for pregnant women in our country. In postnatal period NGS
is used for the examination of selected genes by gene panels, or, if necessary, the entire
genome/exome research, all with the aim as efficient diagnostics primarily monogenic,
but oligogenic and polygenic diseases also. It is proposed that the analysis of even
complete genome become part of neonatal screening, but for now it is not accepted yet. It
is undeniable that the results of NGS make a great progress in medical ā genetic practice,
but gained new ethical dilemmas in the field of early detection of hereditary disorders
and intervention in these situation
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