76 research outputs found
Inorganic metal halide perovskite nanocrystals and thin films:photophysics, photovoltaics, and environmental impact
Inorganic metal halide perovskite nanocrystals and thin films:photophysics, photovoltaics, and environmental impact
The effects of personality dimensions on cardiovascular reactivity in patients with coronary artery disease
UVOD: Jedna od mera stresne reakcije zdravih i obolelih osoba od koronarne bolesti je kardiovaskularna reaktivnost koja se definiÅ”e kao promena veliÄine kardiovaskularnih parametara (npr. puls, sistolni pritisak) tokom izlaganja fiziÄkom ili psiholoÅ”kom stresoru, u odnosu na njihove vrednosti u stanju mirovanja. Na kardiovaskularna reaktivnost utiÄu mnogobrojni Äinioci kao Å”to su genetska predispozicija, pol, životno doba, vrste stresora, strategije prevladavanja stresa, aktuelno raspoloženje, itd. Primenom razliÄitih inventara liÄnosti potvrÄeno je da i pojedine dimenzije liÄnosti znaÄajno dorinose individualnim razlikama kardiovaskularne reaktivnosti na stres.
CILJ: Glavni cilj naÅ”eg istraživanja bio je da se ispita uticaj opÅ”tih dimenzija liÄnosti i Tipa D liÄnosti na kardiovaskularnu reaktivnost kod pacijenata sa dijagnozom koronarne bolesti, uzimajuÄi u obzir potvrÄene moderatore (pol, depresivnost, stilovi prevladavanja stresa).
METOD: Uzorak je Äinilo je 100 ispitanika izabranih metodom prigodnog uzorkovanja, podeljenih u dve grupe: a) studijska grupa (n=79) kojom su obuhvaÄeni pacijenati sa dijagnozom stabilne koronarne bolesti i b) kontrolna grupa zdravih ispitanika (n=21) odgovarajuÄih sociodemografskih karakteristika. Istraživanje je sprovedeno u periodu od 2001. do 2007. godine u Klinici za kardiovaskularne bolesti KCS. Kod svih ispitanika izveden je mentalni stres test kombinovan sa testom fiziÄkim optereÄenjem, u saradnji sa kardiologom, Å”to je praÄeno i ehokardiografski. Eksperimentalna faza istraživanja. Mentalni stres test kombinovan sa testom fiziÄkim optereÄenjem izvoÄen je kod svih ispitanika u podne (1200h), u kontrolisanim klimatskim uslovima. Test se sastojao iz tri faze: a) psihijatrijski interviju, neposredno pre eksperimenta; b) faza odmora: u tihoj i delimiÄno zamraÄenoj prostoriji ergo-kabineta ispitanik se 10-15 minuta odmarao u ležeÄem položaju; c) test mentalnog stresa koji obuhvata dva zadatka: usmeno raÄunanje i zadatak koji reaktivira ljutnju. Instrumenti procene. Prvo je sproveden polustrukturisani intervju u cilju prikupljanja podataka relevantnih za istraživanje (sociodemografske karakteristike, faktori rizika za koronarnu bolest). Nakon laboratorijskog testa i psihijatrijskog intervjua, svi ispitanici popunili su bateriju testova koja je ukljuÄivala sledeÄe instrumente: a) Revidiran nov upitnik liÄnosti, forma S (NEO Personality Inventory - Revised, NEO-PI-R) za pocenu dimenzija liÄnosti; b) Skala D14 (The D-Scale 14, DS-14) za procenu komponenti distres liÄnosti - Negativni afektivitet i Socijalna inhibicija; c) Upitnik o stilovima prevladavanja stresa (Ways of Coping Questionnaire - WCQ-R); d) Bekova skala za procenu depresije (Beck Depression Inventory - BDI)...Introduction: Over the past few decades, cardiovascular reactivity (CVR) has come to be viewed as a meassure of the stress reaction in patients with coronary heart disease as well as in healthy subjects. CVR is defined as a change of the measures of cardiovascular activity (i.e. heart rate, blood pressure) during exposure to physical or psychological stress, comparing to their values in the rest state. Many factors might contribute to the individual differences in CVR, such as genetic predisposition, gender, age, types of stressors, way of coping, affectivity, etc. Furthermore, many studies confirmed that specific personality dimensions play a significant role in the indivdual differences in CVR.
Purpose: The main purpose of our investigation was to examine the effects of personality dimensions on cardiovascular reactivity (CVR) to experimentally induced stress, taking into account the confounding variables (i.e. gender, depression, and coping with stress).
Methodology: The sample consisted of non-consecutive case series of seventy nine patients with clinically stable and angiographically confirmed coronary artery disease (CAD) who had been admitted to the Clinic of Cardiology, University Clinical Centre, and twenty one healthy persons of the control group. The participants were included in the study during the period of six years (from 2001 to 2007). The test was conducted in three phases: a) Initial psychiatric assessment; b) Rest phase: participants rested in a lying position for 10-15 minutes in a partially darkened room; c) Application of the Mental stress test (MST) that consists of two tasks: mental arithmetic and an anger recall task. Continuous 12-lead ECG and blood pressure were monitored and recorded every 5 minutes throughout the rest and the MST procedure. Afterwards, all participants were administered the following battery of psychological tests: a) NEO Personality Inventory - Revised, NEO-PI-R); b) The D-Scale 14, DS-14; c) Ways of Coping Questionnaire - WCQ-R; and d) Beck Depression Inventory - BDI.
Results: The results of the study showed that patients with coronary heart disease scored higher than healthy controls on Neuroticism and lower on Extraversion and Openness to Experience. There were no statistically significant differences on Agreeableness and Conscientiousness. The prevalence of Type D personality was higher in patients with stable coronary heart disease than in the healthy control group. The mean NA/SI scores, also, were higher in patients with stable coronary heart disease than in the healthy control group. Neuroticism and Extraversion shared about 48% and 38% variance with Negative affectivity and Social inhibition, respectively. Correlation analyses indicated that both Type D dimensions (NA, SI) were positively associated with Neuroticism, while negatively associated with Extraversion and Conscientiousness. In addition, we found negative correlation between Negative affectivity and Agreeableness, as well as, negative correlation between Social inhibition and Openness to Experience..
Cold and hot hexane extraction of oil from olive pulp and seeds of Leccino cultivar
U ovom radu istražena je uÄinkovitost hladne i tople (Soxhlet) ekstrakcije ulja iz suhe tvari liofiliziranih maslinovih tijesta (bez koÅ”tice i s koÅ”ticom) te iz sjemenki ploda masline sorte Leccino. Istražen je i utjecaj ekstrakcije na sadržaj ukupnih fenolnih tvari i orto-difenola u dobivenim uljima. U maslinovim tijestima i sjemenkama odreÄen je udio ukupnih fenola i antioksidacijski kapacitet (IC50). Hladna i topla ekstrakcija pokazale su se podjednako uÄinkovite u izdvajanju ulja iz liofiliziranih maslinovih tijesta, dok je topla ekstrakcija bila uÄinkovitija u izdvajanju ulja iz sjemenki. Maslinova tijesta bez koÅ”tice imala su najveÄi udio fenolnih tvari (12,9 mg g-1 s.t.) od tri ispitivana biljna materijala. Stoga su i ulja dobivena iz njih, osobito ona dobivena toplom ekstrakcijom, sadržavala najveÄe udjele ukupnih fenola (396,7 mg kg-1) i orto-difenola (206,3 mg kg-1). U odnosu na maslinova tijesta, sjemenke su imale statistiÄki znaÄajno niži udio ukupnih fenola te viÅ”estruko niži antioksidacijski kapacitet. Rezultati su potvrdili da se uklanjanjem koÅ”tice smanjuje negativni utjecaj peroksidaza iz sjemenki na fenolne tvari u tijestu i ulju, te upuÄuju da se primjenom tople ekstrakcije poveÄava topljivost fenolnih tvari iz biljnog materijala u ulju.In this work, the effectiveness of cold and hot (Soxhlet) extraction of oil from the dry matter of lyophilized olive pastes (without pit and with pit) and seeds of olive fruits of Leccino cultivar, was investigated. The effect of extraction on the content of total phenols and ortho-diphenols in the obtained oils was also investigated. Total phenols content and antioxidant capacity (IC50) were determined in olive pastes and seeds. Cold and hot extraction proved to be equally effective in extracting oil from lyophilized olive pastes, while hot extraction was more efficient in extracting oil from seeds. Olive pastes without pits had the highest total phenols content (12.9 mg g-1 of dry mass) of the three investigated plant materials. Therefore, the oils obtained from them, particularly those obtained by Soxhlet extraction, contained the highest total phenols content (396.7 mg kg-1) and ortho-diphenols (206.3 mg kg-1). Compared to olive pastes, the seeds had a statistically significantly lower total phenols content and a multiple lower antioxidant capacity. The results confirmed that pits removal reduces the negative influence of peroxidases from seeds on the phenol compounds in the olive paste and in the oil, also suggesting that hot extraction increases the solubility of phenols from plant material in the oil
One-pot synthesis of biocompatible NaYF4:Yb,Er nanoparticles for cell labeling
In modern medical research, great attention has been focused to the development of the new biomarkers which include up-converting nanoparticles (UCNPs). Their optical response is triggered by NIR radiation that achieves deeper tissue penetration when compared with traditionally used fluorophores. In this work, biocompatible NaYF4: Yb, Er nanoparticles were synthesized by polymer assisted one-pot solvothermal processing using chitosan or poly(lacticco- glycolic acid). X-ray powder diffraction and electron microscopy results revealed differences in crystal arrangement and morphology of the as-synthesized particles. Fourier transform infrared spectroscopy confirmed the presence of corresponding polymers moiety on UCNPs surface providing their biocompatibility and low cytotoxicity towards human gingival fibroblasts (HFG). As a consequence of efficient up-conversion, prominent green emission (between 512-533nm and between 533-560nm) as well as red emission (630-690nm) were recorded in the particles photoluminescence spectra, and these are applied further in the visualization of the HFG using the laser scanning microscopy with a NIR laser source
Citrate assisted solvothermal synthesis of beta-NaYF4: Yb, Er up-converting nanoparticles
Thanks to the unique optical properties, up-converting nanoparticles (UCNPs) have a wide application in optoelectronics, forensics, security and biomedicine. The synthesis of the most efficient hexagonal Ī²-NaYF4: Yb/Er phase is usually performed through thermal decomposition of organic precursors which could cause the UCNP cytotoxicity. Since cubic polymorph is kinetically more stable than hexagonal, we used citric acid and Na-citrate for the nucleation of hexagonal NaYF4: Yb, Er phase in nanosized particles. Additionally, effect of different precipitation agents (NaF, NH4F and NH4HF2) used during solvothermal synthesis is explored. The XRPD analysis showed that using of citric acid led to a product composed from mixture of cubic and hexagonal NaYF4: Yb/Er phase, while the presence of Na-citrate influences the nucleation of well crystallized hexagonal Ī²-NaYF4: Yb/Er phase, regardless of precipitation agents used. All samples are composed of polycrystalline spherical particles which size is influenced by the precursor chemistry. UCNPs emit intense green emission due to the (2H11/2, 4S3/2) ā 4I15/2 electronic transitions, after been excited with infrared light (Ī»=978 nm)
Effect of Gd3+ introduction on YF3: Yb, Er structural, morphological and optical properties
Monosized up-converting nanoparticles (UCNPs) with a spherical shape and biocompatible surface have a wide application in biomedicine as new cell markers or light-triggered drug delivery agents. The synthesis of the hexagonal Ī²-NaYF4:Yb/Er phase is of a great interest, because of its most efficient up-conversion luminescence. Beside it, synthesis of the UCNPs based on YF3:Yb/Er phase is also attractive due to its orthorhombic phase arrangement and fact that higher concentration of dopants could be introduced in such crystal lattice. In this work the synthesis of pure and Gd-doped YF3:Yb/Er phases were performed through hydro/solvo thermal method using a biocompatible chitosan as a surfactant. The XRD analysis showed that independently of the gadolinium content formation of the orthorhombic phase is achieved, but intensity of the green emission due to the (2H11/2, 4S3/2) ā 4I15/2 electronic transitions was highest for un-doped YF3:Yb/Er sample
Polyacrilic Acid and Chitosan Assisted Solvothermal Synthesis of Up-converting NaYF4: Yb,Er Particles
There is a growing interest for development of a facile and reproducible approach for the synthesis of biocompatible lanthanide doped up-converting nanoparticles (UCNPs) for deep tissue imaging and targeted drug delivery. Synthesis of such particles is usually performed through the decomposition of organometallic compounds, followed either with a ligands exchange or with a biocompatible layer coating. In this work, biocompatible NaYF4:Yb,Er (17 mol% Yb; 3 mol% Er) nanoparticles were synthesized by one-pot hydrothermal processing with an assistance of chitosan (Ch) or polyacrylic acid (PAA). Obtained powders were analyzed by X-ray powder diffraction (XRPD, Bruker D8 Discovery), field emission scanning electron microscopy (FE-SEM, Zeiss, DSM 960), transmission electron microscopy (TEM, JEOL JEM 2010), Fourier transform infrared (FTIR, Thermo Scientific Nicolet 6700) and photoluminescence (PL, Spex Fluorolog with C31034 cooled photomultiplier) spectroscopy. The results showed that although both powders crystallize in the same crystal arrangement (cubic, Fm-3m), particles size, shape and optical properties are dependent on the polymer used
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