On The Development of a Mobile Survey Framework with Dynamic Code Loading

Conducting research based on surveys and experiment is a laborious task. This report describes the design and implementation of a system that aims to reduce some of the workload researchers are facing when gathering data from the general population. This is achieved by creating a survey framework which allows the creation and distribution of surveys, as well as the collection of surveys results. In addition to textual questions, the framework allows the researcher to include coded experiments which are distributed with the survey and loaded by the framework at runtime. The survey tool, implemented on the Android™ platform, supports Android-based code modules but also web content and Unity code modules. Interfaces to facilitate communication between external code modules and the survey tool are in place for each of the three supported module types. The generic nature of the framework coupled with its modularity and the ability to work without a permanent network connection make is suitable for a vast number of research scenarios. To show the feasibility of the system, a survey investigating the correlation between cognitive function and driver behaviour is conducted. It shows the level of automation that can be achieved and, simultaneously validates the system. System tests were used to verify the framework

Conant's Metric Spectra Problem

In this paper, we try to minimize the scope of possible unique metric spectra up to equivalence. While it is well known that every spectra $S\subseteq \mathbb{R}^+$ is equivalent to a spectra $T\subseteq \mathbb{N}$, it has remained open if $T$ could also maintain a desirable combinatorial form. Conant questioned if $T= \{t_1,...,t_n \}_{<}$ could be taken such that $2^i-1 \leq t_i \leq 2^n -1$. In this paper, we come to two partial answers. The first is that the largest element $t_n$ can be chosen such that $t_n\leq 2^n$. Approximating a full solution, we also observe $T$ with the combinatorial form $2^i \leq t_i \leq 2^{n+1}$. Our methods are rather unique in the field as we utilize linear optimization and polygonal geometry to achieve our results. Our work aims to approach a full characterization of metric spectra, and simplify future computational endeavors in the field

Uticaj HIV infekcije i antiretrovirusnih lekova na starenje parodontalnih tkiva

Aging of periodontal tissues, as well as organism as a whole, is natural, unstoppable process of accumulation of undesirable changes which lead to disturbancy of chomeostasis, loss of function and increased susceptibility to diseases and death. Dynamic of this process is often unpredictable because individuals, organs, tissues, cells, and even subcellular structures do not have the same rate of aging. Considering that, the biological aging of the individuals does not neccesarily match their chronological aging. Furthermore, some conditions and pathological processes could increase the speed of aging. It has been shown that patients with human immunodeficency virus (HIV) infection age faster than their non-infected counterparts. The altered aging in HIV-infected patients could be triggered by infection itself or due to usage of antiretroviral drugs, which increased life expectancy in these patients. Various biological markers of aging could be used in order to determine the difference between biological and chronological age of the patient, and to differ premature aging or aging-related diseases from physiological aging. The aim of this research was to identify the relations between periodontal tissue aging and biomarkers of aging such as, relative telomere length, iron metabolism parameters and presence of periodontal pathogens within oral cavity. Investigation was designed as a cross-sectional study. The study enrolled 105 HIV-infected and 100 non-infected male subjects subdivided in two age groups: younger ( lt 35 years of age) and older (>50 years of age). After signing the informed consent, anamnestic data, blood samples and buccal swabs were collected from each patient and detailed oral examinations were performed. The blood samples were used for relative telomere length and iron metabolism parameters (serum iron, total iron binding capacity, transferrin saturation and concentrations of transferrin and ferritin) analyses. The buccal swabs were used for the identification of periodontal pathogens: Prevotella intermedia, Peptostreptococcus micros, Aggregatibacter actinomycetemcomitans, Eikenella corrodens, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola. Oral manifestations of HIV-infection were detected by inspection and periodontal parameters were determined by probing. Results of this study indicate that relative telomere length is longer in younger patients in both, HIV-infected and non-infected group, compared to their older counterparts...Starenje parodontalnih tkiva, kao i čitavog organizma, je prirodan, nezaustavljiv proces koji se karakteriše nakupljanjem neželjenih promena koje dovode do poremećaja homeostaze, gubitka funkcije i većom verovatnoćom za pojavu oštećenja, bolesti i smrti jedinke. Dinamika ovog procesa se razlikuje među jedinkama, ali postoje razlike i u samom organizmu jer organi, tkiva, ćelije, pa čak i subcelularne strukture ne stare istom brzinom. Posledično, biološka starost jedinke ne mora da odgovara njenoj hronološkoj starosti. Dalje, pojedina stanja i patološki procesi mogu dovesti do ubrzanog starenja. Pokazano je da osobe zaražene virusom humane imunodeficijencije (engl. Human Immunodeficiency Virus, HIV) fenotipski brže stare od neinficiranih osoba što može da bude posledica same infekcije i/ili primene antiretrovirusnih lekova, koji su značajno produžili životni vek pacijentima sa HIV-om. Upotrebom različitih markera starenja moguće je razlikovati biološku od hronološke starosti individue, ali i razlikovati prerano starenje odnosno bolesti koje su u vezi sa starenjem od fiziološkog starenja. Cilj ovog istraživanja bio je da se utvrdi veza između starenja parodontalnih tkiva i različitih bioloških markera starenja kao što su dužina telomera, parametri metabolizma gvožđa i dobno zavisna smena prisustva parodontopatogena kod HIV-om inficiranih pacijenata i neinficiranih kontrola. Istraživanje je dizajnirano kao studija preseka. U studiju je bilo uključeno 105 HIV-om inficiranih i 100 neinficiranih ispitanika muškog pola podeljenih u dve starosne grupe: mlađu sa ispitanicima do 35 godina života i stariju sa ispitanicima koji imaju više od 50 godina. Nakon potpisanog informisanog pristanka od ispitanika su dobijeni anamnestički podaci, uzorci krvi i bris oralne sluzokože, a odrađen je i detaljan stomatološki pregled. Iz uzoraka krvi određivani su relativna dužina telomera leukocita i parametri metabolizma gvožđa, serumsko gvožđe, ukupni kapacitet transferina za vezivanje gvožđa, saturacija transferina i koncentracije transferina i feritina. Iz briseva oralne sluzokože detektovani su sledeći parodontopatogeni mikroorganizmi: Prevotella intermedia, Peptostreptococcus micros, Aggregatibacter actinomycetemcomitans, Eikenella corrodens, Porphyromonas gingivalis, Tannerella forsythia i Treponema denticola. Inspekcijom usne duplje utvrđivano je prisustvo oralnih manifestacija karakterističnih za HIV-infekciju dok je parodontološki pregled poslužio za procenu stanja potpornog aparata zuba..

Supplementary data for article: Džambaski, Z.; Toljic, D.; Bondzic, B.; Marković, R.; Baranac-Stojanović, M. Unusual Mode of Reactivity of 2-Alkylidene-4-Oxothiazolidine S-Oxides under the Pummerer Reaction Conditions. Tetrahedron 2013, 69 (46), 9819–9825. https://doi.org/10.1016/j.tet.2013.09.004

Supplementary material for: [https://doi.org/10.1016/j.tet.2013.09.004]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1434

Genetički polimorfizmi paraoksonaze 1 i podložnost aterogenezi

Introduction. Paraoxonase 1 (PON1) is a multifunctional enzyme associated with high-density lipoprotein particles (HDL). It is a cellular antioxidant that hydrolyses oxidized macromolecules, especially low-density lipoproteins (ox-LDL). Because increased oxidative stress is believed to play a crucial role in the initiation and propagation of atherosclerosis, coding (Q192R and L55M) and promoter (C(-107)T) region polymorphisms of pon1 gene, that are responsible for catalytic efficiency, activity and the level of the enzyme, have been of great interest as a potential markers of susceptibility for atherogenesis. Objective. The aim of the study was to assess possible association between these pon1 gene variants and clinical manifestations of the atherosclerosis and oxidative stress. Methods. A total of 60 angiographically documented patients with manifested atherosclerotic disease and 100 control individuals were analyzed. Genomic DNA was isolated from the peripheral blood cells and genotyping was performed using polymerase chain reaction followed by the restriction fragment length polymorphism (PCR-RFLP) analysis. Results No significant difference in allele and genotype frequencies of all three examined polymorphisms was found between the atherosclerotic patients and healthy controls. The obtained results could not support an association of pon1 gene variants with the oxidative stress and atherogenesis. Conclusion. These polymorphisms cannot be considered risk factors of atherosclerosis in Serbian population. A larger study is required in order to establish possible contribution of pon1 variants to atherosclerosis-related cardiovascular diseases.Uvod. Paraoksonaza 1 (PON1) je multifunkcionalni enzim koji je vezan za lipoproteine visoke gustine (HDL). To je ćelijski antioksidans koji hidrolizuje oksidovane makromolekule, naročito oksidovane lipoproteine niske gustine (ox-LDL). Smatra se da povišeni oksidativni stres igra ključnu ulogu u inicijaciji i propagaciji ateroskleroze, pa su polimorfizmi u kodirajućem (Q192R i L55M) i promotorskom (C(-107)T) regionu gena pon1, koji su odgovorni za katalitičku efikasnost, aktivnost i nivo enzima, od velikog interesa kao potencijalni markeri osetljivosti na aterogenezu. Cilj rada. Cilj ove studije je bio da se ispita moguća povezanost varijanti gena pon1 i kliničkih manifestacija ateroskleroze i oksidativnog stresa. Metode rada. Analizirano je 60 bolesnika s angiografski dokumentovanim manifestacijama ateroskleroze i 100 zdravih ispitanika. Genomska DNK je izolovana iz ćelija periferne krvi, a genotipizacija je urađena primenom reakcije lančane polimeraze, posle koje je urađena analiza dužine restrikcionih fragmenata (tzv. PCR-RFLP analiza). Rezultati. Učestalosti alela i genotipova tri ispitivana polimorfizma nisu pokazale značajne razlike između ispitanika obolelih od ateroskleroze i zdravih osoba. Dobijeni rezultati ne ukazuju na povezanost analiziranih varijanti gena pon1 i oksidativnog stresa i aterogeneze. Zaključak. Ovi polimorfizmi se ne mogu smatrati faktorima rizika za razvoj ateroskleroze u srpskoj populaciji. Potrebna je studija sa većim brojem ispitanika, kako bi se utvrdio mogući doprinos varijanti gena pon1 na nastanak kardiovaskularnih oboljenja u čijoj osnovi je ateroskleroza

Late and post-collisional tectonic evolution of the Adria-Europe suture in the Vardar Zone

The Vardar Zone is a product of the Triassic-Jurassic opening of the Neotethys, Jurassic obduction, Late Cretaceous/Paleogene consumption of the oceanic crust and continental collision. During the last process, the Eastern Vardar Zone was thrust over the Central and eventually both onto the Western Vardar Zone. The present paleomagnetic and structural study provided new results from the first two zones in the Belgrade area. The younger set of data, together with published ones from the third zone, provide firm evidence for about 30° clockwise vertical axial rotation of the Vardar Zone between 23-18 Ma, connected to extension driven by the roll-back of the Carpathians lithosphere. Earlier, the Vardar Zone was affected by intensive compression generating a nappe pile, comprising the Eastern, Central and Western Vardar Zones. This assembly was eventually thrusted over CCW rotating Adriatic elements in the Paleogene. The rotation triggered a system of right lateral strike slip faults between different tectonic slices in the Vardar Zone. This tectonic model offers a plausible explanation for the paleomagnetic directions of post-folding age of the Upper Cretaceous flysch of the Central Vardar Zone. Nevertheless, the possibility of remagnetization of the magnetite bearing flysch during Late Neogene uplift can not be excluded

The Effect of Liquid-Phase Exfoliated Graphene Film on Neurodifferentiation of Stem Cells from Apical Papilla

Background: Dental stem cells, which originate from the neural crest, due to their easy accessibility might be good candidates in neuro-regenerative procedures, along with graphene-based nanomaterials shown to promote neurogenesis in vitro. We aimed to explore the potential of liquid-phase exfoliated graphene (LPEG) film to stimulate the neuro-differentiation of stem cells from apical papilla (SCAP). Methods: The experimental procedure was structured as follows: (1) fabrication of graphene film; (2) isolation, cultivation and SCAP stemness characterization by flowcytometry, multilineage differentiation (osteo, chondro and adipo) and quantitative PCR (qPCR); (3) SCAP neuro-induction by cultivation on polyethylene terephthalate (PET) coated with graphene film; (4) evaluation of neural differentiation by means of several microscopy techniques (light, confocal, atomic force and scanning electron microscopy), followed by neural marker gene expression analysis using qPCR. Results: SCAP demonstrated exceptional stemness, as judged by mesenchymal markers’ expression (CD73, CD90 and CD105), and by multilineage differentiation capacity (osteo, chondro and adipo-differentiation). Neuro-induction of SCAP grown on PET coated with graphene film resulted in neuron-like cellular phenotype observed under different microscopes. This was corroborated by the high gene expression of all examined key neuronal markers (Ngn2, NF-M, Nestin, MAP2, MASH1). Conclusions: The ability of SCAPs to differentiate toward neural lineages was markedly enhanced by graphene film

Raman microspectroscopy: toward a better distinction and profiling of different populations of dental stem cells

Aim To characterize stem cells originating from different dental tissues (apical papilla [SCAP], dental follicle [DFSC], and pulp [DPSC]) and test the capacity of Raman microspectroscopy to distinguish between the three dental stem cell types. Methods SCAR DFSC, and DPSC cultures were generated from three immature wisdom teeth originating from three patients. Cell stemness was confirmed by inducing neuro-, osteo-, chondro-, and adipo-differentiaton and by mesenchymal marker expression analysis by flow-cytometry and real-time polymerase chain reaction. Cellular components were then evaluated by Raman microspectroscopy. Results We found differences between SCAP, DFSC, and DPSC Raman spectra. The ratio between proteins and nucleic acids (748/770), a parameter for discriminating more differentiated from less differentiated cells, showed significant differences between the three cell types. All cells also displayed a fingerprint region in the 600-700 cm(-1) range, and characteristic lipid peaks at positions 1440 cm(-1) and 1650 cm(-1). Conclusion Although different dental stem cells exhibited similar Raman spectra, the method enabled us to make subtle distinction between them

Supplementary data for article: Džambaski, Z.; Toljic, D.; Bondzic, B.; Marković, R.; Baranac-Stojanović, M. Unusual Mode of Reactivity of 2-Alkylidene-4-Oxothiazolidine S-Oxides under the Pummerer Reaction Conditions. Tetrahedron 2013, 69 (46), 9819–9825. https://doi.org/10.1016/j.tet.2013.09.004

Supplementary material for: [https://doi.org/10.1016/j.tet.2013.09.004]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1434

The presence of periopathogenic bacteria in subgingival and atherosclerotic plaques- An age related comparative analysis

Introduction: There is a known connection between periodontitis and atherosclerosis and the presence of periopathogens in blood vessels. However, changes of the oral microflora related to the aging process and its possible effects on atherosclerosis, have yet to be analyzed. The aim of this study was to assess temporal changes in the frequency of periodontal bacteria in the subgingival plaque and in atherosclerotic blood vessels of patients with atherosclerosis. Methodology: The study included 100 patients with atherosclerosis and periodontitis, divided into two groups, below and over 60 years of age. Clinical examinations were performedand subgingival plaque specimens were collected as well as biopsy specimens from the following arteries: coronary (34), carotid (29), abdominal (10), femoral (10), mammary (13) and iliac (4). Subgingival and artery specimens were subjected to PCR detection of 5 major periodontal pathogens: Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Aggregatibacter actinomycetemcomitans (Aa), Tannerella forsythensis (Tf) and Treponema denticola (Td). Results: Tf was the most and Td the least frequent bacteria in both age groups and in both types of samples. The frequencies of bacteria in subgingival versus atherosclerotic samples were: Tf (76%: 53%), Pi (71%: 31%), Pg (60%: 38%), Aa (39%: 14%) and Td (21%: 6%). Only Aa and Pi showed a significant difference of prevalence between younger and older patients. The most colonized artery was a. coronaria, followed by a. carotis, a. abdominalis, a. mammaria, and a. femoralis. Conclusions: Patient's age and the distance of a given blood vessel from the oral cavity influenced microbiological findings in the atherotic plaque