Investigations of the application of inorganic substrates based on TiO2 nanocrystals for the detection and quantification of small molecules with SALDI TOF mass spectrometry

MALDI TOF (Matrix-Assisted Laser Desorption and Ionization Time-Of-Flight) mass spectrometry is soft ionization technique. In order to prevent/reduce fragmentation of analyzed molecules, induced with direct excitation with laser, samples are mixed with matrix molecules. Matrix has high absorption coefficient in the range of the laser emission. In spite of numerous advantages, there are serious drawbacks of the matrices, especially for the analysis of molecules with low molecular mass (above 1000 Da). In this group of molecules there are various biologically active molecules, so there is a great need to overcome disadvantages of the application of organic matrices. Several alternative approaches have been developed: an organicmatrix-free approach in which the substrates, usually nanoparticles act as a matrix. The term SALDI (Surface-Assisted Laser Desorption and Ionization) was coined to designate the techniques that use nanostructured substrates. Nanoparticles absorb the laser energy and then rapidly transfer to analyzed molecule. Titanium (IV)-oxide (TiO2) is considered to be a good candidate for SALDI substrate since it is readily available, chemically stable, non-toxic and inexpensive material. TiO2 is a semiconductor with high absorptivity of UV light of nitrogen laser (have a large band gap 3.2 eV) which is used in MALDI TOF mass spectrometry, but the method of synthesis of TiO2 nanocrystal have a great impact on absorption because this phenomenon depends on size, shape and composition of nanoparticles. The applicability of TiO2 nanocrystals of different size and shape was tested. Colloidal TiO2 nanoparticles, TiO2 prolate nanospheroids and TiO2 nanotubes were used as substrates for potential SALDI TOF MS quantitative analysis of biologically active molecules with small molecule mass. First step to test efficiency of TiO2 nanocrystal for the mass spectrometry analysis of small molecules was to examine their qualitative characteristics as substrates. It is shown that they have high tolerance to increased concentration on inorganic salts and to high laser intensity. Next step was to examine qualitative characteristics of TiO2 nanocrystals substrates for mass spectrometric analysis based on following parameters: the homogeneity of the distribution of analyte over substrate surface in SALDI approach define reproducibility and accuracy of the measurement, within day precision to compare the accuracy of measurements with respect to signal intensity and potential use of tested systems for quantitative analysis, and day-to-day reproducibility. Based on all results, the great potential of TiO2 nanocrystals (especially for the TiO2 prolate nanospheroids) for the quantitative and qualitative analysis of biologicaly relevant small molecules (Mm less than 1000 Da) was demonstrated. [1-4]VII International School and Conference on Photonics : PHOTONICA2019 : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 26-30; Belgrad

„Ne ono što mogu, već ono što bih trebao”: uloga kompatibilnosti identiteta u objašnjenju socioekonomskih razlika u obrazovnim aspiracijama

Educational inequalities associated with differences in social class backgrounds remain stable in many Western societies, where students from lower social classes generally have lower academic prospects. Previous research suggested that psychological barriers could explain part of this social class attainment gap. This study aimed to investigate the role of identity compatibility in explaining the relationship between high school students’ socioeconomic background and their educational aspirations. Identity compatibility is defined as perceived compatibility between students’ socioeconomic background and a stereotype of a university student. A total of 362 high school students from Croatia completed an online survey that measured their subjective socioeconomic status, identity compatibility, educational aspirations, and their school achievement. The results showed positive associations between the students’ subjective socioeconomic status and identity compatibility, which was, in turn, positively associated with their educational aspirations. The parallel multiple mediation model confirmed the significant indirect effect of subjective socioeconomic status on educational aspirations via identity compatibility, while the path via school achievement was not significant. These findings suggest that part of the social class educational aspiration gap could be explained by the perceived lack of compatibility between one’s social class identity and future university student identity, potentially leading to lower university enrolment rates among lower social class students. Practical considerations of study results are discussed in terms of the potential of socio-psychological interventions in reducing the social class educational aspiration gap.Socioekonomske obrazovne nejednakosti u mnogim zapadnim društvima i dalje opstaju. Pokazalo se da učenici iz obitelji nižega socioekonomskog statusa postižu lošije akademske ishode od svojih vršnjaka iz obitelji višega socioekonomskog statusa. Prijašnja istraživanja također upućuju na potencijalnu ulogu psiholoških barijera u objašnjenju dijela tih obrazovnih nejednakosti. U skladu s time, cilj je ovoga istraživanja bio ispitati ulogu kompatibilnosti identiteta u objašnjenju odnosa između socioekonomskoga porijekla srednjoškolaca i njihovih obrazovnih aspiracija. Kompatibilnost identiteta odnosi se na percipirani sklad između socioekonomskoga porijekla učenika i stereotipa tipičnoga studenta. U istraživanju su sudjelovala 362 učenika srednjih škola u Hrvatskoj. Učenici su ispunili mrežni upitnik u kojemu su mjereni njihov subjektivan socioekonomski status, kompatibilnost identiteta, obrazovne aspiracije i školski uspjeh. Rezultati su pokazali pozitivnu povezanost između subjektivnoga socioekonomskog statusa učenika i kompatibilnosti identiteta te njihovih obrazovnih aspiracija. Paralelni medijacijski model potvrdio je značajan indirektni efekt subjektivnoga socioekonomskog statusa učenika na njihove obrazovne aspiracije preko percipirane kompatibilnosti identiteta, dok se put preko školskoga uspjeha nije pokazao značajnim. Ti nalazi upućuju na to da se dio socioekonomskih razlika u obrazovnim aspiracijama srednjoškolaca može pripisati razlikama u percipiranoj kompatibilnosti identiteta učenika iz obitelji različitih socioekonomskih prilika. Moguće je da niska kompatibilnost identiteta dovodi do nižih stopa upisa fakulteta kod učenika iz obitelji nižega socioekonomskog statusa. U praksi bi, stoga, trebalo djelovati na smanjenje različitih psiholoških barijera kod učenika nižega socioekonomskog statusa provedbom kontekstualno primjerenih sociopsiholoških intervencija

Artroskopska tehnika “sve unutar zgloba” za rekonstrukciju rupturiranog meniska

The most frequent indication for surgical treatment of the knee is lesion of the meniscus. The “all inside” arthroscopic technique with bioresorptive material for meniscus lesion is becoming the most popular treatment. This prospective study included 10 patients with posterior meniscal horn lesion operatively treated at Sports Traumatology Department. The “all inside” technique was performed by intra-articular application of bioresorptive pins-Darts sticks or Meniscus Viper and bioresorptive string. Patients were followed up for 2-6 months postoperatively and graded according to the IKDC 2000 scale. All surgical treatments showed satisfactory results. Young patients with acute longitudinal peripheral lesion-posterior horn lesions, in the red-red or red-white meniscal zone, 1-2 centimeters long are most appropriate for this type of treatment. In these patients, this technique proved to be superior and free from the risk of neurovascular damage. For better authentication of this conclusion, additional prospective randomized studies should be performed.Ozljeda meniska je najčešća indikacija za kirurško liječenje koljena. Artroskopska tehnika “sve unutar zgloba” (“all inside”) za rekonstrukciju lezije meniska upotrebom bioresorpcijskih materijala sve je popularniji način liječenja ozljeda meniska. Prospektivno je analizirano iskustvo u operacijskom liječenju 10 bolesnika zbog ozljede stražnjeg roga meniska na Traumatološkom odjelu. Tehniku “sve unutar zgloba” proveli smo intraartikularnom aplikacijom bioresorpcijskih pinova Darts sticks i/ili upotrebom Vipera meniska i bioresorpcijskog konca. Bolesnici su praćeni tijekom poslijeoperacijskog razdoblja od 2 do 6 mjeseci, a rezultati svih postupaka ocjenjivani prema ocjenskoj ljestvici IKDC 2000 za koljenski zglob su bili zadovoljavajući. Idealni kandidati za takav zahvat su mlađe osobe s akutnom, longitudinalnom, perifernom lezijom, tj. stražnji rog, u crveno-crvenoj ili crveno-bijeloj zoni meniska, dužine 1-2 cm. U takvih bolesnika, tehnika “sve unutar zgloba” u liječenju ozljede meniska pokazala se vrlo dobrom, jer omogućuje cjelokupan intraartikularni tretman bez rizika od neurovaskularnih ozljeda. Za procjenu vjerodostojnosti takvih zaključaka potrebne su veće prospektivne randomizirane studije

The interaction between variously shaped TiO2 nanoparticles with UV laser determines the quality of the mass spectra of carbohydrates

The important factor that determines the process of the laser-induced desorption and ionization of molecules for the mass spectrometric analysis is the interaction between the laser light and the substrate. It is of importance that substrate efficiently absorbs laser energy, which will be further rapidly transferred to the analyte. The overall goal in this process is to obtain good quality mass spectrum with low degree of fragmentation. Whereas the application of organic matrices instead of substrates results in the numerous undesired polymerization reactions, which complicate the spectra, and in some cases, even prevent the detection of the ions of interests, nanoparticles as substrates are convenient due to a lower number of background signals and low onset of fragmentation reactions in the gas phase. Titanium dioxide (TiO2) is semiconductor-based and widely used substrate for laser desorption and ionization ((SA)LDI), and when it is in the excited state it transfers an electron or energy into the ground state molecule. This process is called sensitized photoreaction [1]. The desorption/ionization processes on TiO2 nanoparticles are related to the physical properties of the substrate such as ability to absorb and dissipate energy from the irradiating laser light source [2]. TiO2 has a large band gap (bulk anatase: 3.2 eV), and can therefore be used as a SALDI matrix with the N2 laser (337 nm) [3]. The aim of our study is to investigate the influence, which the interaction of the UV laser with TiO2 nanoparticles of various shapes and size has on the quality of the mass spectra of carbohydrates: D-(+)-glucose, D-(+)-maltose, raffinose, arabinose, β-ciclodextrine, substances which are otherwise difficult for mass spectrometric analysis. For this purpose, we used small, nearly spherically shaped colloidal TiO2 nanoparticles (average diameter ~ 5 nm), prolate nanospheroids (length: 40–50 nm, the lateral dimension: 14–16 nm) and nanotubes (length: 100-150 nm, average diameter 11 nm). For comparison, the spectra are acquired also with traditionally used organic matrices. The spectra of carbohydrates with organic matrices are overloaded with matrix signals, in which case the signals arising from the analyte of interest are suppressed, or it is possible to detect only adducts with matrix. Laser-induced ionization on nanostructures offers alternative ionization pathways through the formation of Na+ and K+ adducts with appreciable yield [4]. TiO2 nanotubes showed extraordinary properties for detection of carbohydrates. Arabinose was detectable only with TiO2, and D-(+)-glucose and D-(+)-maltose were detected in negative ion mode, which was not the case with other organic matrices and substrates. Not only the highest intensities of mass peaks but also the smallest coefficient of variation was achieved with TiO2 nanotubes. Taken toghether, TiO2 nanotubes, due to their size and the shape, have the most suitable physical properties for the substrate in the SALDI technique. The laser intensity was kept as low as possible in order to prevent fragmentaion. Higher laser intensity is required for the process of desorption/ionization when TiO2 NPs are used (2400 i.u.), but for TiO2 PNSs and TiO2 nanotubes were lower and nearly the same 1950 and 2000 i.u., respectively. In conclusion, larger, tube-shaped TiO2 substrates more efficiently absorb the laser energy and transfer it to the carbohydrates, enabling their desorption/ionization and preventing their fragmentation.V International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 and the Second international workshop "Control of light and matter waves propagation and localization in photonic lattices" : PHOTONICA2015 : book of abstracts; August 24-28, 2015; Belgrad

Platypnea-orthodeoxia syndrome related to the patent foramen ovale and atrial septal aneurysm

The platypnea-orthodeoxia syndrome is a rare condition characterized by postural dyspnea and hypoxemia that disappear or diminish in lying position, so it can be difficult to recognize without close assessment of the patient\u27s pattern of dyspnea. The syndrome is commonly associated to an intra-cardiac right-to-left shunt through a patent foramen ovale as the most frequently reported site of the shunt. Platypnea-orthodeoxia syndrome can be the cause of refractory hypoxemia leading to pulmonary hypertension, whereby, if suspected, contrast echocardiography in supine as well as in upright position should be performed. We are presenting a case of an unrecognized platypnea-orthodeoxia syndrome because of a patent foramen ovale and atrial septal aneurysm, with developed chronic complications due to long-standing hypoxemia. This case highlights the need of a high index of suspicion to diagnose the syndrome on time and the necessity of careful echocardiographic evaluation

Detection of Ru potential metallodrug in human urine by MALDI-TOF mass spectrometry: validation and options to enhance the sensitivity

We studied the possibility of detection of [Ru(η5 -C5H5)(PPh3)2Cl] (abbreviated by RuCp) complex as a model system for Ru-based metallodrugs in human urine by using matrix-assisted laser desorption/ionization time-of flight mass spectrometry (MALDI-TOF MS) without previous purification or removal of inorganic salts. Inorganic salts might prevent the detection of RuCp by MALDI-TOF MS, most likely through the increased number and intensity of background/organic matrix signals. This problem might be overcome by the acquisition of matrix free spectra and the addition of nanoparticles, such as carbon dots, to the urine solution. Our results suggest that RuCp is easily detectable by MALDI-TOF MS in all acquisition conditions, with the CHCA matrix being the best for acquisition in phosphate-containing solutions, whereas in urine, DHB and matrix-free approach demonstrated the highest sensitivity, precision, and reproducibility. The sensitivity of matrix-free MALDI detection of RuCp could be increased by the addition of carbon dots to the urine. Based on theoretical calcu lations for all matrix/analyte combinations, the model for the interaction of RuCp with carbon dots was established, and higher sensitivity explained.info:eu-repo/semantics/publishedVersio

Vodeni ekstrakt kaduljina lišća umanjuje upalu i oksidacijsku genotoksičnost u ljudskim mononuklearnim stanicama periferne krvi

Traditional medicine has used sage (Salvia officinalis L.) preparations for centuries to prevent and treat various inflammatory and oxidative stress-induced conditions. The aim of this in vitro study was to determine the bioactive properties of a sage leave extract obtained with environmentally friendly aqueous extraction and lyophilisation in primary human peripheral blood cells. To that end we measured the total phenolic and flavonoid content (TPC and TFC, respectively) with gas chromatography-mass spectrometry (GC-MS). Non-cytotoxic concentrations determined with the trypan blue assay were used to assess the antioxidant (DPPH, ABTS, and PAB assay), antigenotoxic (CBMN assay), immunomodulatory (IL-1β and TNF-α), and neuroprotective effects (AChE inhibition). The extract contained high TPC (162 mg GAE/g of dry extract) and TFC (39.47 mg QE/g of dry extract) concentrations, while β-thujone content was unexpectedly low (below 0.9 %). Strong radical-scavenging activity combined with glutathione reductase activation led to a decrease in basal and H2O2-induced oxidative stress and DNA damage. A decrease in TNF-α and increase in IL-1β levels suggest complex immunomodulatory response that could contribute to antioxidant and, together with mild AChE inhibition, neuroprotective effects. Overall, this study has demonstrated that aqueous sage leave extract reduces the levels of thujone, 1,8-cineole, pinene, and terpene ketones that could be toxic in high concentrations, while maintaining high concentrations of biologically active protective compounds which have a potential to prevent and/or treat inflammatory and oxidative stress-related conditions.Salvia officinalis L. stoljećima se koristi u tradicionalnoj medicini za prevenciju i liječenje raznih upalnih i oksidacijskim stresom izazvanih poremećaja. U ovoj studiji željeli smo ekstrahirati kaduljino lišće korištenjem ekološki prihvatljivog, “zelenog” pristupa vodenom ekstrakcijom i liofilizacijom te odrediti njegova bioaktivna svojstva u primarnim ljudskim perifernim krvnim stanicama. Ukupni sadržaj fenola i flavonoida i GC-MS korišteni su za karakterizaciju ekstrakta. Necitotoksične koncentracije, određene metodom bojenja s bojom tripan plavo, analizirane su za procjenu antioksidacijskih (DPPH, ABTS i PAB test), antigenotoksičnih (CBMN test), imunomodulacijskih (IL-1β i TNF-α) i neuroprotektivnih učinaka (AChE inhibicija). Ekstrakt je sadržavao visoku koncentraciju ukupnih fenola (162 mg GAE/g liofilizata) i flavonoida (39,47 mg QE/g liofilizata), dok je sadržaj β-tujona bio neočekivano nizak (niži od 0,9 %). Snažna aktivnost hvatanja radikala u kombinaciji s aktivacijom glutation reduktaze dovela je do smanjenja bazalnog i H2O2 induciranog oksidacijskog stresa i oštećenja DNA. Smanjenje TNF-α i povišenje razine IL-1β sugeriraju kompleksan imunomodulatorni odgovor koji bi mogao pridonijeti antioksidacijskim i, zajedno s blagom inhibicijom AChE, neuroprotektivnim učincima. Sveukupno, ova je studija pokazala da vodena ekstrakcija kaduljina lišća smanjuje toksične spojeve kao što su tujon, 1,8-cineol, pinen i terpenski ketoni, a održava visoku koncentraciju biološki aktivnih zaštitnih spojeva u ekstraktu, što bi moglo imati potencijal za prevenciju i/ili liječenje oksidacijskih i upalnih poremećaja

Prikazi i anotacije

Lejla Turčilo, Zaradi pa vladaj: Politika-mediji-biznis u globalnom društvu i u Bosni i Hercegovini; Ivan Šiber (ur.), Hrvatska i Europa – strahovi i nade; Gorana Dojčinović (ur.), Mišljenja i stavovi djece i mladih u Hrvatskoj; Drago Roksandić, U NIN-u i Danasu; Nicholas Carr, Plitko – Što internet čini našem mozg

Svojstva vlakanaca juvenilnog drva bijele topole (Populus alba L.) uz rijeku Dravu

Anatomical properties of white poplar (Populus alba L.) wood have not been sufficiently investigated and quantified, whereas data on fiber characteristics will certainly define its potential as a raw material. Fiber length, double cell wall thickness and fiber lumen diameter of white poplar juvenile wood from two sites along the Drava River in Croatia were measured. Variations in fiber characteristics in radial direction (from pith to bark), within and between white poplar populations from two sites were investigated. Results indicate that fiber Rlength and double cell wall thickness varied significantly from pith to bark, within and between sites. Variation in fiber lumen diameter was non-significant only between sites. The variation in radial pattern was characterized by increase in fiber length with cambial age. Double cell wall thickness and fiber lumen diameter varied in non-consistent radial pattern. In conclusion, variation significance demonstrates nonhomogeneous wood fiber characteristics at both sites.Anatomska svojstva drva bijele topole (Populus alba L.) nedovoljno su istražena i nisu kvantificirana, a podatci o obilježjima drvnih vlakanaca zasigurno će upozoriti na potencijal tog drva kao sirovine. U radu je izmjerena duljina vlakanaca, dvostruka debljina stijenki i promjer lumena vlakanaca juvenilnog drva bijele topole s dva staništa uz rijeku Dravu. Istražene su i varijacije svojstava vlakanaca u smjeru od srčike prema kori, kao i unutar istog staništa odnosno između dvaju promatranih staništa. Rezultati pokazuju značajne varijacije duljine vlakanaca i dvostruke debljine stijenki od srčike prema kori te unutar istog staništa i između dvaju staništa. Varijacije promjera lumena vlakanaca nisu značajne samo među staništima. Radijalne su varijacije određene rastom duljine vlakanaca sa starošću drva. Dvostruka debljina stijenki i promjer lumena vlakanaca mijenjaju se prema promjenjivom modelu između godova. Zaključno, značenje varijacija upućuje na nehomogenost svojstava drvnih vlakanaca na oba staništa