Dragana Jovanovic

Multifunctional Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles synthesized by reverse micelle method

Synthesis of Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles in reverse micelles and their multifunctional luminescence properties are presented. Using cyclohexane, Triton X-100, and n-pentanol as the oil, surfactant, and co-surfactant, respectively, crystalline nanoparticles with ~4 nm diameter are prepared at low temperatures. The particle size assessed using transmission electron microscopy is similar to the crystallite size obtained from X-ray diffraction measurements, suggesting that each particle comprises a single crystallite. Eu3+-doped GdVO4 nanoparticles emit red light through downconversion upon UV excitation. Er3+/Yb3+-doped GdVO4 nanoparticles exhibit several functions; apart from the downconversion of UV radiation into visible green light, they act as upconvertors, transforming near-infrared excitation (980 nm) into visible green light. The ratio of green emissions from 2H11/2 → 2I15/2 and 4S3/2 → 4I15/2 transitions is temperature dependent and can be used for nanoscale temperature sensing with near-infrared excitation. The relative sensor sensitivity is 1.11%K−1, which is among the highest sensitivities recorded for upconversion-luminescence-based thermometers.

Identification of genes associated with non-small-cell lung cancer promotion and progression

Lung cancer is the most common cause of neoplasia-related death worldwide. One of the crucial early events in carcinogenesis is the induction of genomic instability and mutator phenotype. We investigated genomic instability in 30 patients with non-small-cell lung cancer (NSCLC) by comparing DNA fingerprints of paired tumor and normal tissues using arbitrarily primed polymerase chain reaction (AP-PCR). Selected 21 DNA bands with altered mobility were isolated from polyacrylamide gels, cloned and sequenced. Obtained sequences were submitted to homology search in GenBank database which revealed the following genes: TSPAN14, CDH12, RDH10, CYP4Z1, KIR, E2F4, PHACTR3, PHF20, PRAME family member and SLC2A13. Following the identification of these genes we examined their relation to the clinicopathological parameters and survival of the patients. Our study revealed that genetic alterations of TSPAN14, SLC2A13 and PHF20 appeared prevalently in tumors of grade 1, stage I suggesting that structural changes of these genes could play a role in NSCLC promotion. Contrary to this CYP4Z1, KIR and RDH10 were prevalently mutated in tumors of grade 3, stage III suggesting that they could play a role in NSCLC progression. E2F4, PHACTR3, PRAME family member and CDH12 most probably play important role in NSCLC geneses. In conclusion, our study revealed altered genes previously not described in regard to this type of cancer.

Neodymium-doped nanoparticles for infrared fluorescence bioimaging: The role of the host

The spectroscopic properties of different infrared-emitting neodymium-doped nanoparticles (LaF3:Nd3+, SrF2:Nd3+, NaGdF4: Nd3+, NaYF4: Nd3+, KYF4: Nd3+, GdVO4: Nd3+, and Nd:YAG) have been systematically analyzed. A comparison of the spectral shapes of both emission and absorption spectra is presented, from which the relevant role played by the host matrix is evidenced. The lack of a “universal” optimum system for infrared bioimaging is discussed, as the specific bioimaging application and the experimental setup for infrared imaging determine the neodymium-doped nanoparticle to be preferentially used in each case.

Temperature dependence of emission and lifetime in Eu 3+ - and Dy 3+ -doped GdVO 4

Eu(3+)- and Dy(3+)-doped GdVO(4) samples synthesized by a high-temperature solid-state method are investigated by fluorescence spectroscopy at 298-750 K. They demonstrate potential for development as thermographic phosphors because the experimental and theoretical temperature dependence of the intensity ratio of the two lines agrees well. Experimental lifetime measurements recorded at 10-750 K were fitted using three theoretical models: multiphonon relaxation, temperature quenching through the charge transfer (CT) region, and our modified CT model (TDCT), which considers the temperature dependence of CT energy. The TDCT model yields the best results with good agreement between experimental and fitted lifetime data.

Aberrant Promoter Methylation of CDH13 and MGMT Genes is Associated With Clinicopathologic Characteristics of Primary Non–Small-Cell Lung Carcinoma

UNLABELLED Non–small-cell lung carcinoma (NSCLC) (n = 65) were analyzed for promoter methylation of RASSF1A, CDH13, MGMT, ESR1, and DAPK genes in matching lung tumors, normal lung tissue, and blood samples. Aberrant methylation in CDH13 and MGMT was associated with clinicopathologic features of NSCLC. Hypermethylation detected in primary tumors was not observed in corresponding blood samples, which rendered this an unsuitable blood-based test for NSCLC detection. INTRODUCTION Systemic methylation changes may be a diagnostic marker for tumor development or prognosis. Here, we investigate the relationship between gene methylation in lung tumors relative to normal lung tissue and whether DNA methylation changes can be detected in paired blood samples. MATERIAL AND METHODS Sixty-five patients were enrolled in a surgical case series of non-small-cell lung carcinoma at a single institution. By using bisulfite pyrosequencing, CpG methylation was quantified at 5 genes (RASSF1A, CDH13, MGMT, ESR1, and DAPK) in lung tumor, pathologically normal lung tissue, and circulating blood from enrolled cases. RESULTS The analyses of methylation in tumors compared with normal lung tissue identified higher methylation of CDH13, RASSF1A, and DAPK genes, whereas ESR1 and MGMT methylation did not differ significantly between these tissue types. We then examined whether the 3 aberrantly methylated genes could be detected in blood. The difference in methylation observed in tumors was not reflected in methylation status of matching blood samples, which indicated a low feasibility of detecting lung cancer by analyzing these genes in a blood-based test. Lastly, we probed whether tumor methylation was associated with clinical and demographic characteristics. Histology and sex were associated with methylation at the CDH13 gene, whereas, stage was associated with methylation at MGMT. CONCLUSION Our results showed higher methylation of RASSF1A, CDH13, and DAPK genes in lung tumors compared with normal lung. The lack of reflection of these methylation changes in blood samples from patients with non-small-cell lung carcinoma indicates their poor suitability for a screening test.

Pulsed Laser Deposited Dysprosium‐Doped Gadolinium–Vanadate Thin Films for Noncontact, Self‐Referencing Luminescence Thermometry

Lanthanide-doped vanadate thin films offer (i) a promising platform for luminescence-based noncontact temperature sensing; (ii) ratiometric/self-referencing absolute measurements; (iii) exceptional repeatability and reversibility for multirun uses and a long life cycle; (iv) 2% K(-1) maximum temperature sensitivity (among the highest recorded for inorganic nanothermometers); (v) a temperature resolution greater than 0.5 K; and (vi) the potential for high-resolution 2D temperature mapping.

The Influence of Acid Treatment on the Nanostructure and Textural Properties of Bentonite Clays

The nanostructure and textural properties of acid-activated bentonite clays from the Bogovina coalmine were investigated. The acid activation was performed with HCl in the concentration range 1.5-7.5 M. The atomic force microscopy followed by image analysis was used in order to establish the influence of the acid treatment on the size of bentonite particles. Nitrogen adsorption-desorption isotherms at -196 °C were used to estimate the specific surface area, pore volume and pore size distribution. The acid treatment reduces the size of bentonite particles and increases the specific surface area and pore volume of the investigated bentonites. These effects are improved by increasing the acid concentration up to 4.5 M HCl. Further increase in acid concentration does not result in development of new porous structure.

Thermographic properties of Sm3+-doped GdVO4 phosphor

Rare-earth orthovanadates are important hosts for the luminescence of rare earth activators with considerable practical applications in the artificial production of light. In this paper we investigated the possibility for GdVO4:Sm3+ usage in phosphor thermometry by observing the temperature changes of trivalent samarium transitions from 4F3/2 and 4G5/2 energy levels to the ground state. A set of three samples of Sm3+-doped GdVO4 (0.5, 1 and 2 mol.% Sm3+ with respect to Gd3+ ions) was produced via solid state synthesis. The sample crystalline structure is confirmed from x-ray diffraction (XRD) measurements. Photoluminescence measurements were recorded in the temperature range 293–823 K and the fluorescence intensity ratio of the paired emissions bands was studied as a function of temperature. All three GdVO4:Sm3+ samples proved to have good potential for the development of thermographic phosphors, whereas the maximum sensitivity of approximately 4.5×10-4 K−1 was found for the sample with 2 mol.% Sm3+ in the temperature region around 750 K.

Identification and validation of differentially expressed transcripts by RNA-sequencing of formalin-fixed, paraffin-embedded (FFPE) lung tissue from patients with Idiopathic Pulmonary Fibrosis

BackgroundIdiopathic Pulmonary Fibrosis (IPF) is a lethal lung disease of unknown etiology. A major limitation in transcriptomic profiling of lung tissue in IPF has been a dependence on snap-frozen fresh tissues (FF). In this project we sought to determine whether genome scale transcript profiling using RNA Sequencing (RNA-Seq) could be applied to archived Formalin-Fixed Paraffin-Embedded (FFPE) IPF tissues.ResultsWe isolated total RNA from 7 IPF and 5 control FFPE lung tissues and performed 50 base pair paired-end sequencing on Illumina 2000 HiSeq. TopHat2 was used to map sequencing reads to the human genome. On average ~62 million reads (53.4% of ~116 million reads) were mapped per sample. 4,131 genes were differentially expressed between IPF and controls (1,920 increased and 2,211 decreased (FDR < 0.05). We compared our results to differentially expressed genes calculated from a previously published dataset generated from FF tissues analyzed on Agilent microarrays (GSE47460). The overlap of differentially expressed genes was very high (760 increased and 1,413 decreased, FDR < 0.05). Only 92 differentially expressed genes changed in opposite directions. Pathway enrichment analysis performed using MetaCore confirmed numerous IPF relevant genes and pathways including extracellular remodeling, TGF-beta, and WNT. Gene network analysis of MMP7, a highly differentially expressed gene in both datasets, revealed the same canonical pathways and gene network candidates in RNA-Seq and microarray data. For validation by NanoString nCounter® we selected 35 genes that had a fold change of 2 in at least one dataset (10 discordant, 10 significantly differentially expressed in one dataset only and 15 concordant genes). High concordance of fold change and FDR was observed for each type of the samples (FF vs FFPE) with both microarrays (r = 0.92) and RNA-Seq (r = 0.90) and the number of discordant genes was reduced to four.ConclusionsOur results demonstrate that RNA sequencing of RNA obtained from archived FFPE lung tissues is feasible. The results obtained from FFPE tissue are highly comparable to FF tissues. The ability to perform RNA-Seq on archived FFPE IPF tissues should greatly enhance the availability of tissue biopsies for research in IPF.

Verifying Sarcoidosis Activity: Chitotriosidase Versus ACE in Sarcoidosis – A Case-Control Study

Summary Background: Until now, a proper biomarker(s) to evaluate sarcoidosis activity has not been recognized. The aims of this study were to evaluate the sensitivity and specificity of the two biomarkers of sarcoidosis activity already in use (serum angiotensin converting enzyme – ACE and serum chitotriosidase) in a population of 430 sarcoidosis patients. The activities of these markers were also analyzed in a group of 264 healthy controls. Methods: Four hundred and thirty biopsy positive sarcoidosis patients were divided into groups with active and inactive disease, and groups with acute or chronic disease. In a subgroup of 55 sarcoidosis patients, activity was also assessed by F-18 fluorodeoxyglucose positron emission tomography (18F-FDG-PET) scanning. Both serum chitotriosidase and ACE levels showed non-normal distribution, so nonparametric tests were used in statistical analysis. Results: Serum chitotriosidase activities were almost 6 times higher in patients with active sarcoidosis than in healthy controls and inactive disease. A serum chitotriosidase value of 100 nmol/mL/h had the sensitivity of 82.5% and specificity of 70.0%. A serum ACE activity cutoff value of 32.0 U/L had the sensitivity of 66.0% and the specificity of 54%. A statistically significant correlation was obtained between the focal granulomatous activity detected on 18F-FDG PET/CT and serum chitotriosidase levels, but no such correlation was found with ACE. The levels of serum chitotriosidase activity significantly correlated with the disease duration (P<0.0001). Also, serum chitotriosidase significantly correlated with clinical outcome status (COS) categories (ρ=0.272, P=0.001). Conclusions: Serum chitotriosidase proved to be a reliable biomarker of sarcoidosis activity and disease chronicity.