Babeş-Bolyai University
  • Cluj-Napoca, Cluj, Romania
Recent publications
Dioximes as ligands are used as analytical reagents and serve as models for biological systems as well as catalysts in chemical processes. A number of novel mixed complexes of the type [Fe(DioxH) 2 (amine) 2 ] have been prepared and characterised by FTIR, ⁵⁷ Fe Mössbauer and mass spectroscopy by us. We have found strong Fe–N donor acceptor interactions and iron occurred in low-spin Fe II state in all complexes. Later, we have also found that the incorporation of branching alkyl chains (isopropyl) in the complexes alters the Fe–N bond length and results in high-spin iron(II) state [1, 2]. The question arises: can the spin state of iron be manipulated generally by replacing the short alkyl chains with high volume demand ones in Fe-azomethine-amine complexes? To answer the question we have synthetized novel iron-bis-glioxime and iron-tris-gloxime complexes when long chain alkyl or aromatic ligands replaced the short alkyl ones and studied by ⁵⁷ Fe Mössbauer spectroscopy, MS, FTIR, UV-VIS, TG-DTA-DTG and XRD methods. Novel iron-bis-glyoxime and iron-tris-glyoxime type complexes, [Fe(Diethyl-Diox) 3 (BOH) 2 ], [Fe(Diethyl-Diox) 3 (BOEt) 2 ] and [Fe(phenyl-Me-Diox) 3 (BOEt) 2 ], were synthesized similarly as described in [2]. The FTIR, UV-VIS, TG-DTA-DTG and MS measurements indicated that the expected novel complexes could be successfully synthesized.
Background Bladder cancer (BC) has the highest per-patient cost of all cancer types. Hence, we aim to develop a non-invasive, point-of-care tool for the diagnostic and molecular stratification of patients with BC based on combined microRNAs (miRNAs) and surface-enhanced Raman spectroscopy (SERS) profiling of urine. Methods Next-generation sequencing of the whole miRNome and SERS profiling were performed on urine samples collected from 15 patients with BC and 16 control subjects (CTRLs). A retrospective cohort (BC = 66 and CTRL = 50) and RT-qPCR were used to confirm the selected differently expressed miRNAs. Diagnostic accuracy was assessed using machine learning algorithms (logistic regression, naïve Bayes, and random forest), which were trained to discriminate between BC and CTRL, using as input either miRNAs, SERS, or both. The molecular stratification of BC based on miRNA and SERS profiling was performed to discriminate between high-grade and low-grade tumors and between luminal and basal types. Results Combining SERS data with three differentially expressed miRNAs (miR-34a-5p, miR-205-3p, miR-210-3p) yielded an Area Under the Curve (AUC) of 0.92 ± 0.06 in discriminating between BC and CTRL, an accuracy which was superior either to miRNAs (AUC = 0.84 ± 0.03) or SERS data (AUC = 0.84 ± 0.05) individually. When evaluating the classification accuracy for luminal and basal BC, the combination of miRNAs and SERS profiling averaged an AUC of 0.95 ± 0.03 across the three machine learning algorithms, again better than miRNA (AUC = 0.89 ± 0.04) or SERS (AUC = 0.92 ± 0.05) individually, although SERS alone performed better in terms of classification accuracy. Conclusion miRNA profiling synergizes with SERS profiling for point-of-care diagnostic and molecular stratification of BC. By combining the two liquid biopsy methods, a clinically relevant tool that can aid BC patients is envisaged.
The current analysis aims to find the solution to the buoyancy effect on time-dependent flow and heat transfer induced by a hybrid micropolar nanofluid over a permeable shrinking or stretching vertical flat plate. A novel hybrid nanofluid is utilized, which consists of the agglomeration of water (pure fluid) and two dissimilar nanoparticles like silver (Ag) and titanium dioxide (TiO2). Initially, the model is developed in the form of the non-linear partial differential equations (PDEs) with three independent variables, which are transformed to the set of dimensionless ordinary differential equations (ODEs) using the appropriate similarity transformations. These dimensionless ODEs are solved numerically via the bvp4c package in MATLAB software. The consequence of various involved controlling parameters on the velocity, microrotation, friction drag, temperature, and heat transfer characteristics for the upper branch solution (UPBS) and the lower branch solution (LOBS) are thoroughly inspected. In physical engineering quantities of interest, it is deeply observed that for the case of stretching, the solution of the stable (upper) branch is possible for the entire negative and positive selected values of the stretching/shrinking parameter. In contrast, the lower branch solution exists only for negative values of the stretching/shrinking parameter for the shrinking case.
Background Emotional disorders are the most prevalent mental health conditions affecting children and adolescents. Thus, it becomes essential to develop and test early intervention strategies that are accessible and attractive as therapeutic strategies and can effectively improve youth's emotional and psychobiological reactivity to distress. Methods A randomized control trial compared the prevention effects of a newly-developed therapeutic game based on Rational Emotive Behavior Education, REThink, to those of a standard, face-to-face group Rational Emotive Behavior Education (REBE) and those of a waitlist. Out of 142 healthy children and adolescents who completed the intervention stage, 137 completed follow-up assessment measuring subjective anxiety and biological stress reactivity in an impromptu speech task. Results No differences were found between groups at follow-up in terms of subjective state anxiety variations between baseline, anticipation, speech and recovery. In terms of the psychobiological index, results showed an increase in left asymmetry for the REThink group at post-test and follow-up compared to pre-intervention levels. The same trend was found for the WL group, but not for the REBE group. Conclusions Preliminary results suggest that decreases in the biological reactivity can be maintained in the long run following a therapeutic video game for children and adolescents. Future research needs to clarify the adequate usage of the therapeutic videogames to bring significant improvements in the psychobiological functioning of the youths.
Both within science and society, transdisciplinary approaches are increasingly employed to address today’s sustainability challenges. Often transdisciplinary research processes are structured in three core phases: a) problem identification and formation of a common research object; b) co-production of solution-oriented and transferable knowledge; c) embedding co-produced knowledge through transdisciplinary reintegration. In all phases of this ideal-typical model, the involvement of non-academic actors is essential to meet the challenges of real-world problems, and of transformative research practices. Despite existing guidance for the core transdisciplinary process, its initiation often remains an uncharted area because of its strong context dependency. Based on a concrete transdisciplinary case study addressing sustainability transformation in Transylvania, we bring together our learned experience with initiating a transdisciplinary process using a research-driven approach. To this end, we introduce the notion of Phase 0, as an initiating phase prior to beginning an ideal-typical transdisciplinary process. Within Phase 0, we propose three empirically and literature informed sub-phases: Sub-Phase 0.1) selecting the case study; Sub-Phase 0.2) understanding the case study context from a transdisciplinary perspective; Sub-Phase 0.3) fostering premises for coming together. We outline the general rationale behind these sub-phases, and we illustrate how we carried out each sub-phase in practice. By deriving cross-cutting lessons from the three sub-phases, we enhance the practice of transdisciplinary sustainability research with the aim to leverage its transformative potential.
Using an operator approach, we discuss stationary solutions to Fokker-Planck equations and systems with nonlinear reaction terms. The existence of solutions is obtained by using Banach, Schauder and Schaefer fixed point theorems, and for systems by means of Perov’s fixed point theorem. Using the Ekeland variational principle, it is proved that the unique solution of the problem minimizes the energy functional, and in case of a system that it is the Nash equilibrium of the energy functionals associated to the component equations.
We identify some classes C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {C}$$\end{document} of mixed groups such that if G∈C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$G\in \mathcal {C}$$\end{document} has the cancellation property then the Walk-endomorphism ring of G has the unit lifting property. In particular, if G is a self-small group of torsion-free rank at most 4 with the cancellation property then it has a decomposition G=F⊕H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$G=F\oplus H$$\end{document} such that F is free and the Walk-endomorphism ring of H has the unit lifting property.
Nowadays, due to the constant increase in size and complexity of the software systems imposed by their evolution, developing qualitative software systems becomes a highly important task. To achieve this goal, early detection of software defects is a must. The paper proposes an approach to generate rules for software defect prediction. In this respect, a Software Defects Rules Discovery (SDRD) algorithm was put forward. This one uses the ant colony system method to discover the best solution based on code metrics values. We conducted 20 experiments in total (five experiments with three metrics and 15 experiments with combinations of two metrics). The results revealed that the metrics that correlate with the dependent variable are CBO (Coupling Between Objects), RFC (Response For a Class) and NPM (Number of Private Methods), and that from all the combinations of two metrics, for the five projects, the best obtained rule is formed with RFC and NPM metrics.
For the first time, the laminar jet in a free-stream flow around a corner with/without a moving wall condition (as it assists the flow) is studied theoretically. The corner may contract the streamlines or expand them depending on the angle of inclination. In the context of incompressibility, it is presented a composite non-similar transformation of the Navier-Stokes (N-S) equations in Cartesian space to approximately decipher the nature of the boundary layer flow over the entire physical domain; i.e. 0 ≤ x, y < ∞. The transformed Partial Differential Equations (PDEs) are then solved by an in-house MATLAB code, which employs an implicit algorithm of a tridiagonal form with quasi-linearization technique. For a stationary wall, as the negative angle of the corner meets Falkner-Skan (F-S) limitation and expands beyond, the predictive model starts to show a critical location, which reveals directly the flow separation point. This critical location moves toward the jet origin as the angle of inclination becomes more negative. Here, these locations are extracted as a function of the inclination parameter in order to manifest the suitability of a jet to delay boundary layer separation. A similar scenario also applies to the moving wall case. In this case, it was recorded that a moving wall condition delays separation for a considerable distance. It should be pointed out that up to date, there is no theoretical investigation on this specific flow geometry despite the many associated applications; and the limited available reports on an analogous flow geometry are those from the Computational Fluid Dynamics (CFD) and on a case by case basis. More specifically, the present geometry is quite similar to the flow passing the way down to the trailing edge of an airfoil, with a jet generator mechanism such as Dielectric Barrier Discharge (DBD) plasma actuator to delay flow separation on the backside of the airfoil. Here, by the use of the theoretical non-similarity concept empowered by some recent advancements (see Jafarimoghaddam, 2020 and Jafarimoghaddam, 2021), the fundamental problem of a jet discharged in the lower boundary of a freestream flow over a wedge is successfully solved. This theoretical breakthrough suggests promising avenues for the future design of airfoils with moving parts/flaps as an innovative step forward to enhance maneuverability of the flying objects.
Magnetic nanofluids (MNFs) have been widely applied in both biomedical and environmental sectors along with the substantial growth of numerical and experimental studies. Hence, in view of the unique properties in MNFs, the aim of this study is to analyze numerically the three‐dimensional flow of MNFs (Fe3O4–water, CoFe2O4–water, Mn–ZnFe2O4–water) over a shrinking surface with suction and thermal radiation effects. The single‐phase nanofluid model is reduced into a system of ordinary differential equations by applying the similarity transformation. The results are then, obtained using the bvp4c solver in the Matlab software. The results reveal that for the shrinking case, the Mn–ZnFe2O4–water nanofluid has the maximum thermal rate followed by CoFe2O4–water and Fe3O4–water, respectively. Meanwhile, Fe3O4–water expands the separation value of boundary layer flow greater than other tested MNFs. Besides this, the suction parameter is also a contributing factor for the thermal enhancement of all MNFs.
In this paper, we present a spectroscopic insight into the structural and optical properties of ZnO nanoparticles (NPs) applied for water depollution using the photocatalytic process. Samples of various sizes and shapes were synthesized using simple, cost-effective chemical methods. The steady-state optical properties were analyzed using absorption and fluorescence emission spectroscopy and the band-gap and emission energies revealed an inverse dependence on the ZnO particles size. The time-resolved fluorescence properties were studied using time-correlated single photon counting (TCSPC) technique. Three emissive states were identified for all ZnO samples, with lifetimes that showed an overall decrease with increasing the particles diameter. The insights into the photocatalytic process toward understanding the ZnO nanoparticles mediated photocatalysis for degradation of Rhodamine (RhB) and oxytetracycline (OTC) was elucidated. The increase of photocatalytic activity was due to charge carrier partition and mobility.
In the last decades, anthropogenic drivers have significantly influenced the natural climate variability of Earth's atmosphere. Climate change has become a subject of major interest for different levels of our society, such as national governments, businesses, local administration, or citizens. While national and local policies propose mitigation and adaptation strategies for different sectors, public perception is a key component of any implementation plan. This study investigates the CC perception in Romania, based on a national-scale online survey performed in the spring of 2020, aiming to outline the prominence of environmental and CC issues, level of information and interest, perceived causes, changes perceived in meteorological phenomena at the regional scale, perceived impacts, and the psychological representation of the CC. The study investigates single causal factors of perception. We found that particularly (i) the regional differences on climate change intensity strongly bias the perception of CC causes; (ii) age is very likely to influence the acceptance of CC, the importance of environmental issues, and the levels of information and interest; while (iii) age, gender, and place of residence (rural-urban) are very likely to control the changes perceived in the occurrence of various meteorological phenomena, and their impact. This research is the first statistically relevant analysis (± 4%, statistical significance) developed at national and regional scales and the only study of climate change perception performed during the COVID-19 pandemic in Romania. Its results may represent the baseline for more in-depth research. Supplementary information: The online version contains supplementary material available at 10.1007/s00704-022-04041-4.
There is an increasing need for paleoclimate records from continental settings to better understand the climatic changes during critical periods such as the Pliocene and Early Pleistocene. Present data indicates a transition from a warmer than present-day climate to a substantially different cooler climate. This study reviews the oxygen and carbon isotope compositions of mammalian tooth enamel for the Pliocene and Early Pleistocene of South and Central Europe to reconstruct the spatial distribution and temporal changes of the vegetation and oxygen isotope composition of precipitation (δ¹⁸Oppt). In addition to a literature review, this study adds new stable isotope measurements for this period. All δ¹³C values indicate C3 ecosystems and reflect major changes in the water use efficiency and/or in the prevailing humidity. The reconstructed major floral types range from woodland to woodland ‒ mesic grassland in all of the investigated regions. The carbon isotope compositions of fossil mammal teeth demonstrate that the spatial distribution of vegetation was broadly similar to those of the present-day for the Early/Late Pliocene – Early Pleistocene, with the most “closed” vegetation in Central and Northern Italy, while open mesic grassland vegetation covers can be reconstructed for the Iberian Peninsula, Massif Central region (Central France) and the Carpathian Basin. The calculated δ¹⁸Oppt values give a negative temporal shift of about 1–1.5‰ from the Early Pliocene to Late Pliocene – Early Pleistocene in three regions (Iberian Peninsula, Central Italy, Carpathian Basin), potentially representing a 1.5–3.0 °C decrease in mean annual temperatures (MAT) over time. In the Massif Central region and the Carpathian Basin, the δ¹⁸Oppt values are almost the same for the Late Pliocene and Early Pleistocene, while in Northern Italy the values decreased over that period. The δ¹⁸Oppt values are in the range of present-day δ¹⁸Oppt values over the Early Pliocene and somewhat lower than present-day values for the Late Pliocene - Early Pleistocene in most of the regions. Because most other proxies indicate warmer than present-day climate for the Early Pliocene and similar to present-day climate for the Early Pleistocene, the δ¹⁸Oppt values are generally lower than expected, which can be partially explained by local effects.
A new alloy, permalloy alloyed with aluminum, has been obtained by mechanical alloying using elemental powders as raw materials. The new alloy was obtained in powder form by adding an amount of 5 wt% of Al to permalloy (75% Ni and 25% Fe, wt.%) resulting Al-Permalloy with Ni71.25Fe23.75Al5 composition. The alloy was obtained using different ball to powder ratio (BPR): 4:1, 8:1 and 17:1 and keeping the rest of the mechanical alloying/milling parameter constant. The BPR influences the time required for the alloy synthesis and alloy characteristics. The time required for alloy synthesis as FCC single phase varies from 4 h when using a BPR of 17:1 to 8 h when using a BPR of 4:1. A more compact cubic structure is obtained when using a BPR of 8:1. The particles are flattened for all BPRs used, but upon changing the BPRs particles shape is changing and become more or less flattened. Large particles have been obtained when using BPRs of 4:1 and 17:1 and finer particles when using a BPR of 8:1. Curie temperature of the Al-Permalloy is depending on synthesis conditions varying from 478 °C to 501 °C. The higher saturation magnetization has been found when using a BPR of 8:1. The powder characteristics evolution upon increasing the milling time for all three BPRs is discussed in the light of X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectrometry, differential scanning calorimetry, particles size analyses and magnetic investigation.
Unnatural substituted amino acids play an important role as chiral building blocks, especially for pharmaceutical industry, where the synthesis of chiral biologically active molecules still represents an open challenge. Recently, modification of the hydrophobic binding pocket of phenylalanine ammonia-lyase from Petroselinum crispum (PcPAL) resulted in specifically tailored PcPAL variants, contributing to a rational design template for PAL-activity enhancements towards the differently substituted substrate analogues. Within this study we tested the general applicability of this rational design model in case of PALs, of different sources, such as from Arabidopsis thaliana (AtPAL) and Rhodosporidium toruloides (RtPAL). With some exceptions, the results support that the positions of substrate specificity modulating residues are conserved among PALs, thus the mutation with beneficial effect for PAL-activity enhancement can be predicted using the established rational design model. Accordingly, the study supports that tailoring PALs of different origins and different substrate scope, can be performed through a general method. Moreover, the fact that AtPAL variants I461V, L133A and L257V, all outperformed in terms of catalytic efficiency the corresponding, previously reported, highly efficient PcPAL variants, of identical catalytic site, suggests that not only catalytic site differences influence the PAL-activity, thus for the selection of the optimal PAL-biocatalysts for a targeted process, screening of PALs from different origins, should be included.
The purpose of this study was to examine evidence of reliability, validity, and equity, for the Romanian version of The Screen for Child Anxiety Related Emotional Disorders (SCARED), the 41-item child- (1,106 children and adolescents ranging from 9 to 16 years old) and parent-ratings (485 parents). Both versions of the instrument showed moderate to high internal consistency, with most subscales reaching acceptable levels. Results showed support for the original five-factor structure of the scale. Positive correlations with other measures of anxiety symptoms, such as The Penn State Worry Questionnaire, The Social Anxiety Scale for Adolescents, The Children’s Automatic Thoughts Scale, whereas weak correlations with the syndrome scales for rule-breaking and aggressive behavior of the Youth Self-Report, respectively, Child Behavioral Checklist have demonstrated similar construct validity for the Romanian version of the scale as compared to the original one. Also, strict measurement invariance across age, gender, and clinical status was established. The current research provides evidence of reliability, validity, and equity for SCARED, arguing for its utility as a screening instrument for anxiety symptoms. Implications for theory, assessment, and future research are discussed.
Background This paper enumerates and characterizes latent classes of adverse childhood experiences and investigates how they relate to prenatal substance use (i.e., smoking, alcohol, and other drugs) and poor infant outcomes (i.e., infant prematurity and low birthweight) across eight low- and middle-income countries (LMICs). Methods A total of 1189 mother-infant dyads from the Evidence for Better Lives Study cohort were recruited. Latent class analysis using the Bolck, Croon, and Hagenaars (BCH) 3-step method with auxiliary multilevel logistic regressions was performed. Results Three high-risk classes and one low-risk class emerged: (1) highly maltreated (7%, n = 89), (2) emotionally and physically abused with intra-familial violence exposure (13%, n = 152), (3), emotionally abused (40%, n = 474), and (4) low household dysfunction and abuse (40%, n = 474). Pairwise comparisons between classes indicate higher probabilities of prenatal drug use in the highly maltreated and emotionally abused classes compared with the low household dysfunction and abuse class. Additionally, the emotionally and physically abused with intra-familial violence exposure class had higher probability of low birthweight than the three remaining classes. Conclusion Our results highlight the multifaceted nature of ACEs and underline the potential importance of exposure to childhood adversities on behaviors and outcomes in the perinatal period. This can inform the design of antenatal support to better address these challenges.
In late December 2019, the first cases of viral pneumonia caused by an unidentified pathogen were reported in China. Two years later, SARS-CoV-2 was responsible for almost 450 million cases, claiming more than 6 million lives. The COVID-19 pandemic strained the limits of healthcare systems all across the world. Identifying viral RNA through real-time reverse transcription-polymerase chain reaction remains the gold standard in diagnosing SARS-CoV-2 infection. However, equipment cost, availability, and the need for trained personnel limited testing capacity. Through an unprecedented research effort, new diagnostic techniques such as rapid diagnostic testing, isothermal amplification techniques, and next-generation sequencing were developed, enabling accurate and accessible diagnosis. Influenza viruses are responsible for seasonal outbreaks infecting up to a quarter of the human population worldwide. Influenza and SARS-CoV-2 present with flu-like symptoms, making the differential diagnosis challenging solely on clinical presentation. Healthcare systems are likely to be faced with overlapping SARS-CoV-2 and Influenza outbreaks. This review aims to present the similarities and differences of both infections while focusing on the diagnosis. We discuss the clinical presentation of Influenza and SARS-CoV-2 and techniques available for diagnosis. Furthermore, we summarize available data regarding the multiplex diagnostic assay of both viral infections.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.
6,608 members
Elisabeta Cristina Timis
  • Department of Chemical Engineering
  • Raluca Ripan Institute for Research in Chemistry, Department of Analytical Chemistry
Oana Alexandra David
  • Department of Clinical Psychology and Psychotherapy
Anca Farkas
  • Department of Molecular Biology and Biotechnology
Kogalniceanu Str. #1, 400084, Cluj-Napoca, Cluj, Romania
Head of institution
Prof. Dr. Daniel David
00 40 264 405300
00 40 264 591906