Machine Learning Model for Prediction of Development of Cancer Stem Cell Subpopulation in Tumurs Subjected to Polystyrene Nanoparticles

Cancer stem cells (CSCs) play a key role in tumor progression, as they are often responsible for drug resistance and metastasis. Environmental pollution with polystyrene has a negative impact on human health. We investigated the effect of polystyrene nanoparticles (PSNPs) on cancer cell stemness using flow cytometric analysis of CD24, CD44, ABCG2, ALDH1 and their combinations. This study uses simultaneous in vitro cell lines and an in silico machine learning (ML) model to predict the progression of cancer stem cell (CSC) subpopulations in colon (HCT-116) and breast (MDA-MB-231) cancer cells. Our findings indicate a significant increase in cancer stemness induced by PSNPs. Exposure to polystyrene nanoparticles stimulated the development of less differentiated subpopulations of cells within the tumor, a marker of increased tumor aggressiveness. The experimental results were further used to train an ML model that accurately predicts the development of CSC markers. Machine learning, especially genetic algorithms, may be useful in predicting the development of cancer stem cells over time.

Novel N-pyrocatechoyl and N-pyrogalloyl hydrazone antioxidants endowed with cytotoxic and antibacterial activity

Over the years, pharmacological agents bearing antioxidant merits arose as beneficial in the prophylaxis and treatment of various health conditions. Hazardous effects of radical species hyperproduction disrupt normal cell functioning, thus increasing the possibility for the development of various oxidative stress-associated disorders, such as cancer. Contributing to the efforts for efficient antioxidant drug discovery, a thorough in vitro and in silico assessment of antioxidant properties of 14 newly synthesized N-pyrocatechoyl and N-pyrogalloyl hydrazones (N-PYRs) was accomplished. All compounds exhibited excellent antioxidant potency against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The extensive in silico analysis revealed multiple favorable features of N-PYRs to inactivate harmful radical species, which supported the obtained in vitro results. Also, in silico experiments provided insights into the preferable antioxidant pathways. Prompted by these findings, the cytotoxicity effects and the influence on the redox status of cancer HCT-116 cells and healthy fibroblasts MRC-5 were evaluated. These investigations exposed four analogs exhibiting both cytotoxicity and selectivity toward cancer cells. Furthermore, the frequently uncovered antimicrobial potency of hydrazone-type hybrids encouraged investigations on G+ and G- bacterial strains, which revealed the antibacterial potency of several N-PYRs. These findings highlighted the N-PYRs as excellent antioxidant agents endowed with cytotoxic and antibacterial features.

Modeling 5-FU-Induced Chemotherapy Selection of a Drug-Resistant Cancer Stem Cell Subpopulation

(1) Background: Cancer stem cells (CSCs) are a subpopulation of cells in a tumor that can self-regenerate and produce different types of cells with the ability to initiate tumor growth and dissemination. Chemotherapy resistance, caused by numerous mechanisms by which tumor tissue manages to overcome the effects of drugs, remains the main problem in cancer treatment. The identification of markers on the cell surface specific to CSCs is important for understanding this phenomenon. (2) Methods: The expression of markers CD24, CD44, ALDH1, and ABCG2 was analyzed on the surface of CSCs in two cancer cell lines, MDA-MB-231 and HCT-116, after treatment with 5-fluorouracil (5-FU) using flow cytometry analysis. A machine learning model (ML)-genetic algorithm (GA) was used for the in silico simulation of drug resistance. (3) Results: As evaluated through the use of flow cytometry, the percentage of CD24-CD44+ MDA-MB-231 and CD44, ALDH1 and ABCG2 HCT-116 in a group treated with 5-FU was significantly increased compared to untreated cells. The CSC population was enriched after treatment with chemotherapy, suggesting that these cells have enhanced drug resistance mechanisms. (4) Conclusions: Each individual GA prediction model achieved high accuracy in estimating the expression rate of CSC markers on cancer cells treated with 5-FU. Artificial intelligence can be used as a powerful tool for predicting drug resistance.

Evaluation of novel dendrimer-gold complex nanoparticles for theranostic application in oncology

Aim: Despite some successful examples of therapeutic nanoparticles reaching clinical stages, there is still a significant need for novel formulations in order to improve the selectivity and efficacy of cancer treatment. Methods: The authors developed two novel dendrimer-gold (Au) complex-based nanoparticles using two different synthesis routes: complexation method (formulation A) and precipitation method (formulation B). Using a biomimetic cancer-on-a-chip model, the authors evaluated the possible cytotoxicity and internalization by colorectal cancer cells of dendrimer-Au complex-based nanoparticles. Results: The results showed promising capabilities of these nanoparticles for selectively targeting cancer cells and delivering drugs, particularly for the formulation A nanoparticles. Conclusion: This work highlights the potential of dendrimer-Au complex-based nanoparticles as a new strategy to improve the targeting of anticancer drugs.

Bioactivities and Medicinal Value of the Fruiting Body Extracts of Laetiporus sulphureus and Meripilus giganteus Polypore Mushrooms (Agaricomycetes)

In the present investigation methanol and acetone extracts of basidiocarps of mushrooms Laetiporus sulphureus and Meripilus giganteus were evaluated for their antimicrobial, cytotoxic and antioxidant/prooxidant effects. The antimicrobial potential was determined by the microdilution method against ten microorganisms. Cytotoxic effects were evaluated by MTT test, while changes of the redox status parameters (superoxide anion radical, nitrites and reduced glutathione) were determined spectrophotometrically on a human colorectal cancer cell line and human health fibroblasts cells. The results were measured 24 and 72 h after the treatment. Tested extracts exhibited moderate antimicrobial activity with MIC values from 0.004 to 20 mg/mL. The maximum antimicrobial activity was found in the methanol extracts of the M. giganteus against Bacillus subtilis, which was better than positive control. The acetone extract of M. giganteus with IC5072h = 13.36 μg/mL showed significant cytotoxic effect with strong cell selectivity (selectivity index = 37.42) against cancer human colorectal cancer cells. The tested extracts, especially M. giganteus acetone extract, induced an increase in oxidative stress parameters in tested cell lines, but significantly heightened it in human colorectal cancer cells. The obtained results suggest that these extracts, especially M. giganteus acetone extract, can be proposed as a novel source of nutraceuticals and pharmaceuticals.

Tracking variations in daily questionable health behaviors and their psychological roots: a preregistered experience sampling study

People resort to various questionable health practices to preserve or regain health - they intentionally do not adhere to medical recommendations (e.g. self-medicate or modify the prescribed therapies; iNAR), or use traditional/complementary/alternative (TCAM) medicine. As retrospective reports overestimate adherence and suffer from recall and desirability bias, we tracked the variations in daily questionable health behaviors and compared them to their retrospectively reported lifetime use. We also preregistered and explored their relations to a wide set of psychological predictors - distal (personality traits and basic thinking dispositions) and proximal (different unfounded beliefs and biases grouped under the term irrational mindset). A community sample (N = 224) tracked daily engagement in iNAR and TCAM use for 14 days, resulting in 3136 data points. We observed a high rate of questionable health practices over the 14 days; daily engagement rates roughly corresponded to lifetime ones. Both iNAR and TCAM were weakly, but robustly positively related. Independent of the assessment method, an irrational mindset was the most important predictor of TCAM use. For iNAR, however, psychological predictors emerged as relevant only when assessed retrospectively. Our study offers insight into questionable health behaviors from both a within and between-person perspective and highlights the importance of their psychological roots.

Development of a novel instrument for assessing intentional non-adherence to official medical recommendations (iNAR-12): a sequential mixed-methods study in Serbia

OBJECTIVES

We aimed to (1) develop a novel instrument, suitable for the general population, capturing intentional non-adherence (iNAR), consisting of non-adherence to prescribed therapy, self-medication and avoidance of seeking medical treatment; (2) differentiate it from other forms of non-adherence, for example, smoking; and (3) relate iNAR to patient-related factors, such as sociodemographics, health status and endorsement of irrational beliefs (conspiratorial thinking and superstitions) and to healthcare-related beliefs and experiences ((mis)trust and negative experiences with the healthcare system, normalisation of patient passivity).

DESIGN

То generate iNAR items, we employed a focus group with medical doctors, supplemented it with a literature search and invited a public health expert to refine it further. We examined the internal structure and predictors of iNAR in an observational study.

SETTING

Data were collected online using snowball sampling and social networks.

PARTICIPANTS

After excluding those who failed one or more out of three attention checks, the final sample size was n=583 adult Serbian citizens, 74.4% female, mean age 39.01 years (SD=12.10).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary, planned outcome is the iNAR Questionnaire, while smoking was used for comparison purposes.

RESULTS

Factor analysis yielded a one-factor solution, and the final 12-item iNAR Questionnaire had satisfactory internal reliability (alpha=0.72). Health condition and healthcare-related variables accounted for 14% of the variance of iNAR behaviours, whereas sociodemographics and irrational beliefs did not additionally contribute.

CONCLUSIONS

We constructed a brief yet comprehensive measure of iNAR behaviours and related them to health and sociodemographic variables and irrational beliefs. The findings suggest that public health interventions should attempt to improve patients' experiences with the system and build trust with their healthcare practitioners rather than aim at specific demographic groups or at correcting patients' unfounded beliefs.

STUDY REGISTRATION

The design and confirmatory analyses plan were preregistered (https://osf.io/pnugm).

Combined Biological and Numerical Modeling Approach for Better Understanding of the Cancer Viability and Apoptosis

Nowadays, biomedicine is a multidisciplinary science that requires a very broad approach to the study and analysis of various phenomena essential for a better understanding of human health. This study deals with the use of numerical simulations to better understand the processes of cancer viability and apoptosis in treatment with commercial chemotherapeutics. Starting from many experiments examining cell viability in real-time, determining the type of cell death and genetic factors that control these processes, a lot of numerical results were obtained. These in vitro test results were used to create a numerical model that gives us a new angle of observation of the proposed problem. Model systems of colon and breast cancer cell lines (HCT-116 and MDA-MB-231), as well as a healthy lung fibroblast cell line (MRC-5), were treated with commercial chemotherapeutics in this study. The results indicate a decrease in viability and the appearance of predominantly late apoptosis in the treatment, a strong correlation between parameters. A mathematical model was created and employed for a better understanding of investigated processes. Such an approach is capable of accurately simulating the behavior of cancer cells and reliably predicting the growth of these cells.

Coping with Secondary Traumatic Stress

Exposure to the traumatic experiences of others can lead to secondary traumatization (STS), a condition comprising trauma-related symptoms. There is a lack of evidence on efficient ways to mitigate STS among professionals working with refugees, who are secondarily exposed to traumatic content. This study examines the latent structure of coping mechanisms and explores the predictive power of coping strategies for STS in a sample of professionals working with refugees. A total of 288 participants (age: M = 34.01, SD = 10.03; 57.3% female) working with refugees completed the COPE Inventory and Secondary Traumatic Stress Scale. Factor analysis of the COPE Inventory showed that coping mechanisms are grouped around four interrelated factors-Problem-focused, Socially supported emotion-focused, Avoidant, and Passive coping-which accounted for 46.7% of the variance. The regression model showed that Avoidant coping positively predicts negative alterations in cognition, mood, and reactivity (NACMR) and intrusions, and Passive coping was positively associated with NACMR and avoidance. Problem-focused coping was related to lower NACMR and avoidance, while Socially supported emotion-focused coping was not associated with any of the STS symptoms. In total, coping factors accounted for 10.8%, 6.3%, and 4.3% of the variance of NACMR, intrusions, and avoidance, respectively. The study provides a foundation for programs to mitigate STS among professionals working with refugees.

Determining the Individual Theta Frequency for Associative Memory Targeted Personalized Transcranial Brain Stimulation

Non-invasive brain stimulation (NIBS) methods have gained increased interest in research and therapy of associative memory (AM) and its impairments. However, the one-size-fits-all approach yields inconsistent findings, thus putting forward the need for electroencephalography (EEG)-guided personalized frequency-modulated NIBS protocols to increase the focality and the effectiveness of the interventions. Still, extraction of individual frequency, especially in the theta band, turned out to be a challenging task. Here we present an approach to extracting the individual theta-band frequency (ITF) from EEG signals recorded during the AM task. The method showed a 93% success rate, good reliability, and the full range of variability of the extracted ITFs. This paper provides a rationale behind the adopted approach and critically evaluates it in comparison to the alternative methods that have been reported in the literature. Finally, we discuss how it could be used as an input parameter for personalized frequency-modulated NIBS approaches—transcranial alternating current stimulation (tACS) and transcranial oscillatory current stimulation (otDCS) directed at AM neuromodulation.

Effects of online parietal transcranial electric stimulation on associative memory: a direct comparison between tDCS, theta tACS, and theta-oscillatory tDCS

Associative memory (AM) is the ability to remember and retrieve multiple items bound together. Previous studies aiming to modulate AM by various transcranial electric stimulation (tES) techniques were inconclusive, although overall suggestive that tES could be a tool for AM enhancement. However, evidence from a direct comparison between different tES techniques is lacking. Here, in a sham-controlled cross-over experiment, we comparatively assessed the effects of three types of tES—anodal tDCS, theta-band transcranial alternating current stimulation (tACS), and theta-oscillatory tDCS (otDCS), delivered over the left posterior parietal cortex, during a short-term digit-color AM task with cued-recall. The effects were tested in 40 healthy young participants while both oscillatory tES were delivered at a previously determined individual theta frequency (4–8 Hz). All three active stimulations facilitated the overall AM performance, and no differences could be detected between them on direct comparison. However, unlike tDCS, the effects of which appeared to stem mainly from the facilitation of low-memory demand trials, both theta-modulated tACS and otDCS primarily promoted AM in high memory demand trials. Comparable yet differential effects of tDCS, theta tACS, and otDCS could be attributed to differences in their presumed modes of action.

Blinding in tDCS Studies: Correct End-of-Study Guess Does Not Moderate the Effects on Associative and Working Memory

Transcranial direct current stimulation (tDCS) has become a valuable tool in cognitive neuroscience research as it enables causal inferences about neural underpinnings of cognition. However, studies using tDCS to modulate cognitive functions often yield inconsistent findings. Hence, there is an increasing interest in factors that may moderate the effects, one of which is the participants’ beliefs of the tDCS condition (i.e., real or sham) they received. Namely, whether participants’ correct guessing of sham condition may lead to false-positive tDCS effects. In this study, we aimed to explore if participants’ beliefs about received stimulation type (i.e., the success of blinding) impacted their task performance in tDCS experiments on associative (AM) and working memory (WM). We analyzed data from four within-subject, sham-controlled tDCS memory experiments (N = 83) to check if the correct end-of-study guess of sham condition moderated tDCS effects. We found no evidence that sham guessing moderated post-tDCS memory performance in experiments in which tDCS effects were observed as well as in experiments that showed null effects of tDCS. The results suggest that the correct sham guessing (i.e., placebo-like effect) is unlikely to influence the results in tDCS memory experiments. We discuss the results in light of the growing debate about the relevance and effectiveness of blinding in brain stimulation research.

Transcranial Direct Current Stimulation (tDCS) for Memory Enhancement

Memory enhancement is one of the great challenges in cognitive neuroscience and neurorehabilitation. Among various techniques used for memory enhancement, transcranial direct current stimulation (tDCS) is emerging as an especially promising tool for improvement of memory functions in a non-invasive manner. Here, we present a tDCS protocol that can be applied for memory enhancement in healthy-participant studies as well as in aging and dementia research. The protocol uses weak constant anodal current to stimulate cortical targets within cortico-hippocampal functional network engaged in memory processes. The target electrode is placed either on the posterior parietal cortex (PPC) or the dorsolateral prefrontal cortex (DLPFC), while the return electrode is placed extracranially (i.e., on the contralateral cheek). In addition, we outline a more advanced method of oscillatory tDCS, mimicking a natural brain rhythm to promote hippocampus-dependent memory functions, which can be applied in a personalized and non-personalized manner. We present illustrative results of associative and working memory improvement following single tDCS sessions (20 minutes) in which the described electrode montages were used with current intensities between 1.5 mA and 1.8 mA. Finally, we discuss crucial steps in the protocol and methodological decisions that must be made when designing a tDCS study on memory.

Contextual and Psychological Predictors of Militant Extremist Mindset in Youth

The present study aims to identify contextual and psychological factors of proneness to radicalization and violent extremism (RVE) operationalized through the Militant Extremist Mindset scale (MEM) consisting of three distinct aspects: Proviolence (PV), Vile World beliefs (VW), and trust in Divine Power (DP). A community sample of 271 high school students (72% females) from Belgrade and Sandžak regions in Serbia completed: (1) a 24-item MEM scale; (2) contextual measures including a 6-item scale of family dysfunction (FDys) and a 4-item composite measure capturing exposure to a harsh school environment and peer abuse (HSE); (3) psychological measures including the 9-item Right-Wing Authoritarianism scale (RWA), the 5-item Social Dominance Orientation scale (SDO), and the 20-item UCLA Loneliness scale (LON). A path analysis was conducted with contextual factors on the first and psychological factors on the second level of the model predicting the three factors of MEM. LON was positively predicted by FDys and HSE, SDO by HSE only, while RWA was positively predicted by FDys only. Contextual and psychological factors accounted for 27% of the variance in PV (LON, SDO), 15% of the variance in VW (FDys, SDO), and 31% of the variance in DP (RWA). Obtained findings reveal a complex interplay of contextual and psychological drivers in the prediction of different aspects of RVE and build upon existing knowledge on risk factors associated with RVE.

The effects of offline and online prefrontal vs parietal transcranial direct current stimulation (tDCS) on verbal and spatial working memory

Working memory (WM) is a limited-capacity system or set of processes that enables temporary storage and manipulation of information essential for complex cognitive processes. The WM performance is supported by a widespread neural network in which fronto-parietal functional connections have a pivotal role. Transcranial direct current stimulation (tDCS) is rapidly emerging as a promising tool for understanding the role of various cortical areas and their functional networks on cognitive performance. Here we comprehensively evaluated the effects of tDCS on WM by conducting three cross-over counterbalanced sham-controlled experiments in which we contrasted the effects and interactions of the anodal (i.e. facilitatory) tDCS across anterior-posterior (i.e. DLPFC vs PPC) and left-right (i.e. the lateralization) axes, and across online and offline protocols using both verbal and spatial WM (3-back) tasks as outcomes. In the offline protocols, left DLPFC stimulation affected neither verbal nor spatial WM, while left PPC stimulation increased spatial WM. When applied offline over right DLPFC, tDCS improved verbal WM task and marginally enhanced spatial WM; while when tDCS was applied over the right PPC, facilitatory effects were observed on verbal WM. In the online protocol, tDCS did not modulate WM regardless of the task modality or stimulation loci. In summary, the study did not replicate the left DLPFC tDCS effect on WM, found in some of the previous studies, but demonstrated positive effects of stimulation of the right DLPFC as well as PPC bilaterally. The observed effects varied across modality of the 3-back task, and tDCS protocol applied. The results of this study argue for moving towards targeting the lesser-explored stimulation sites within the fronto-parietal network, such as PPC, to gain a better understanding of the usefulness of tDCS for WM neuromodulation.

Biological activity of bis(pyrazolylpyridine) and terpiridine Os(ii) complexes in the presence of biocompatible ionic liquids

New bis(pyrazolylpyridine) Os(ii) complexes showing possible biological activity with diverse modes of action in the presence of biocompatible ionic liquids as non-toxic cosolvents for sparingly soluble complexes.

Latent structure of secondary traumatic stress, its precursors, and effects on people working with refugees

The study aims to examine the latent structure of secondary traumatic stress (STS), its precursors, and the psychological effects of it on the population of service providers working with refugees passing through the Balkan route. A total of 270 service providers (57% female) of different professional backgrounds working directly with refugees took part in the study. Participants were assessed for STS using the Secondary Traumatic Stress Scale, the extent of secondary exposure to trauma (i.e., clients’ traumatic experiences from the countries of origin and travel that were communicated to them directly), depression, anxiety, and quality of life. Comparisons of several confirmatory factor analyses following prominent PTSD conceptualizations showed that the model with three relatively distinct but highly correlated factors–intrusion, avoidance, and the blend of negative alterations in cognitions, mood, and reactivity (NACMR), had the best fit. STS has been shown to be positively correlated both with the amount of different traumatic experiences that were communicated to them as well as with the specific content of those experiences. Path analysis showed that the amount of secondary exposure to the clients’ traumatic experiences during travel, but not in the country of origin, had exclusive relationships with all three factors of STS. NACMR demonstrated direct effects on anxiety and depression symptoms, while intrusions exhibited a direct effect on anxiety-related symptomatology only. The avoidance factor did not have any independent direct effects on anxiety or depression. Finally, the effects of STS factors on quality of life were fully mediated by an increase of depression-related symptomatology. Results provide evidence on the latent structure of the STS which partially deviates from the prominent models of PTSD thus questioning the isomorphism of two constructs on the empirical level. Additionally, findings provide insights on the cascade of events that make professionals working with traumatized people especially vulnerable to STS and broader psychological distress.

Synthesis of New Pt(II) Complex Bearing Organoselenium Ligands and Evaluation of Cytotoxic Activity of Some Structurally Related Pd(II) Complexes

Herein we report the synthesis of new trans-bis(2-phenylselenylmethyl)oxolane)dichloroplatinum(II) complex Pt1. Newly synthetized complex, together with two, structurally related trans-Pd(II) complexes (trans-bis(2-(phenylselenylmethyl)oxolane)dichloropalladium(II) Pd1 and trans-bis(2-(phenylselenylmethyl)oxane)dichloropalladium(II)) Pd2, were screened for cytotoxic activity through in vitro study on the HCT-116 colorectal carcinoma cell line and on the MRC-5 healthy lung pleura cell line. Activity of complexes was assessed by comparing it to the cisplatin. The cells viability and proliferation were determined using MTT assay.

Experimental and quantum chemical study оn the DNA/protein binding and the biological activity of a rhodium(iii) complex with 1,2,4-triazole as an inert ligand

A rhodium(iii) complex with 1,2,4-triazole and a pincer type nitrogen-donor ligand was synthesized, and its interaction with biomolecules was examined.

Ethyl Acetate Extracts of Two Artemisia Species: Analyses of Phenolic Profile and Anticancer Activities Against SW-480 Colon Cancer Cells

Because Artemisia vulgaris L. and Artemisia alba Turra are traditional medicinal plants used for the treatment of different diseases, we evaluated the cytotoxic/apoptotic activity of ethyl acetate extracts from these natural products against human colon cancer cells SW-480. The extracts contained a large amount of the total polyphenols and flavonoids. The phenolic profile showed the presence of phenolic acids (gallic, p-coumaric, vanillic, and ferulic acids) and flavonoids (rutin, myricetin, luteolin, quercetin, and apigenin). 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay indicated that antiproliferative activities of both A. vulgaris and A. alba extracts increased with the extension of time exposure, with decreasing IC50 values. Mitomycin C (MMC) alone had antiproliferative activity, but in combination with plant extracts caused stronger effect with lower IC50 values. Flow cytometry analyses showed that A. alba extract induced higher percentage of SW-480 cells in the early stage of apoptosis (33.5 ± 1.6 vs 0.7 ± 0.1, P < 0.05), whereas the A. vulgaris extract significantly increased the percentage of cells in necrosis (82.4 ± 5.0 vs 53.9 ± 2.3, P < 0.05). In conclusion, A. alba extract can be considered a potential source of bioactive components with anticancer activity or be used as a dietary food supplement or supplement to chemotherapy due to its synergistic effect with the MMC.

The immediate and delayed effects of single tDCS session over posterior parietal cortex on face-word associative memory

Associative memory (AM), an ability to form and retrieve associations between information units is crucial for everyday functioning and is affected by aging as well as by different neurological conditions. It was shown that rTMS over posterior parietal cortex (PPC) can improve AM of face-word pairs. Therefore, we examined if tDCS will produce comparable effects and explore whether the effect would persist one and five days following the stimulation. Thirty-seven healthy participants took part in cross-over sham-controlled study in which they received 20 min of anodal (1.5 mA) or sham tDCS over left PPC. Following tDCS participants completed face-cued word recall and verbal fluency tasks. A randomly selected subsample (N = 18) has completed follow up memory assessments one and five days after the stimulation. Anodal tDCS facilitated AM performance in comparison to sham with the same trend persisting during the 5-day follow-up period. Additionally, participants with lower AM scores had higher relative gain following anodal tDCS. Anodal tDCS had no effect on the control task (verbal fluency). Results support the existence of a specific enhancing effect on AM produced by facilitatory neuromodulation of the PPC. The effect was more prominent in low-performers and it persisted at least 5 days post-stimulation. These findings support the robustness of tDCS effect on AM and provide a foundation for future research that could lead to its future clinical application.

Synthesis of Camphor-Derived Bis(pyrazolylpyridine) Rhodium(III) Complexes: Structure-Reactivity Relationships and Biological Activity

Two novel rhodium(III) complexes, namely, [Rh^III(X)Cl₃] (X = 2 2,6-bis((4 S,7 R)-7,8,8-trimethyl-4,5,6,7-tetrahydro-1 H-4,7-methanoindazol-3-yl)pyridine or 2,6-bis((4 S,7 R)-1,7,8,8-tetramethyl-4,5,6,7-tetrahydro-1 H-4,7-methanoindazol-3-yl)pyridine), were synthesized from camphor derivatives of a bis(pyrazolylpyridine), tridentate nitrogen-donor chelate system, giving [Rh^III(H₂L*)Cl₃] (1a) and [Rh^III(Me₂L*)Cl₃] (1b). A rhodium(III) terpyridine (terpy) ligand complex, [Rh^III(terpy)Cl₃] (1c), was also synthesized. By single-crystal X-ray analysis, 1b crystallizes in an orthorhombic P2₁2₁2₁ system, with two molecules in the asymmetric unit. Tridentate coordination by the N,N,N-donor localizes the central nitrogen atom close to the rhodium(III) center. Compounds 1a and 1b were reactive toward l-methionine (l-Met), guanosine-5'-monophosphate (5'-GMP), and glutathione (GSH), with an order of reactivity of 5'-GMP > GSH > l-Met. The order of reactivity of the Rh^III complexes was: 1b> 1a > 1c. The Rh^III complexes showed affinity for calf thymus DNA and bovine serum albumin by UV-vis and emission spectral studies. Furthermore, 1b showed significant in vitro cytotoxicity against human epithelial colorectal carcinoma cells. Since the Rh^III complexes have similar coordination modes, stability differences were evaluated by density functional theory (DFT) calculations (B3LYP(CPCM)/LANL2DZp). With (H₂L*) and (terpy) as model ligands, DFT calculations suggest that both tridentate ligand systems have similar stability. In addition, molecular docking suggests that all test compounds have affinity for the minor groove of DNA, while 1b and 1c have potential for DNA intercalation.

ODNOS EKSPLICITNIH I IMPLICITNIH MERA STAVA PREMA HOMOSEKSUALNOSTI I VERBALNE PRODUKCIJE

Veliki broj istraživanja pokazuje da eksplicitni i implicitni stavovi determinišu ponašanje. Verbalna produkcija, kao bihejvioralna manifestacija unutrašnjeg sveta osobe prema savremenim psiholingvističkim teorijama predstavlja, kako nameran, tako i automatski proces. Cilj ovog istraživanja bilo je ispitivanje odnosa između različitih mera verbalnog ponašanja u vezi sa homoseksualnošću, sa jedne, i implicitnih i eksplicitnih mera stava prema homoseksualnosti sa druge strane. U istraživanju je učestvovalo 105 ispitanika. Kao mere stava korišćeni su Test homofobije (H25) i Test Implicitnih Asocijacija, dok su mere verbalne produkcije ekstrahovane iz dve eksperimentalne situacije korišćenjem programa za automatsku analizu teksta LIWCser. U prvoj eksperimentalnoj situaciji ispitanici su indirektno usmeravani na stavski objekat (homoseksualnost), dok su u drugoj situaciji instruisani da direktno govore o stavskom objektu. Rezultati su pokazali umerenu povezanost između eksplicitnih i implicitnih mera stava, kao i relativno nisku do umerenu povezanost ovih mera sa pojedinačnim merama verbalne produkcije. Dodatno, pokazalo se da u osnovi verbalne produkcije stoje implicitni i eksplicitni procesi i to da su spontani aspekti verbalne produkcije pre svega vođeni implicitnim procesima, dok namerni aspekti verbalne produkcije predstavljaju manifestaciju eksplicitnih stavova. Dobijeni rezultati u skladu su sa postojećim modelima odnosa implicitnih i eksplicitnih mera stavova i ponašanja, kao i savremenim psiholingvističkim teorijama.

KONSTRUKCIJA I EMPIRIJSKA PROVERA TESTA HOMOFOBIJE

U ovom radu predstavljena je konstrukcija i evaluacija Testa homofobije koji u sadržinskom smislu objedinjuje dosadašnja znanja i ideje o prirodi ovog fenomena. Test homofobije (H25) sastoji se od 25 stavki u formi tvrdnji kojima je pridružena petostepena skala Likertovog tipa. Na uzorku od 476 ispitanika proverene su psihometrijske karakteristike testa i njegova faktorska struktura. U celini test pokazuje dobre psihometrijske karakteristike (KMO = .99, α = .97). Faktorskom analizom ekstrahovana su dva visoko korelirana faktora, koja su interpretirana kao „homoseksualnost kao pretnja za društvo” i „homoseksualnost kao pretnja za mene”. Takođe, test je pokazao zadovoljavajuću konvergentnu validnost spram dve alternativne mere homofobije, kao i visoku predikciju diskriminatornih stavova prema osobama homoseksualne orijentacije. Dodatno, pokazano je da homofobija, merena konstruisanim instrumentom, ima veći broj socio-demografskih i personalnih korelata. Homofobiji su sklonije osobe muškog pola, religiozne osobe, osobe konzervativne političke orijentacije, zatim osobe koje imaju manje kontakta sa homoseksualnom populacijom, i osobe nižih skorova na dimeziji Otvorenosti, a viših na dimenziji Savesnosti. U celini, konstruisani instrument predstavlja pouzdanu i validnu meru heteroseksualnog stava prema homoseksualnoj populaciji, te predstavlja ekonomičan instrument pogodan za primenu, kako u istraživačke tako i u praktične svrhe.

Opšta kreativna sposobnost i aspekti kreativnog mišljenja kod umetnika i neumetnika

U istraživanju je ispitivana razlika između umetnika i neumetnika u pogledu opšte kreativne sposobnosti i različitih aspekata kreativnosti. Uzorak je činilo 128 studenata Univerziteta u Beogradu (66 studenata umetničkih i 62 studenta neumetničkih fakulteta). U istraživanju je korišćen višedimenzionalni test opšte kreativnosti baziran na Gilfordovom modelu kreativnog mišljenja. Ovaj test procenjuje opštu kreativnu sposobnost i četiri aspekta kreativnosti nižeg reda: fluentnost, produktivnost, originalnost i elaboraciju. Rezultati su pokazali da nema razlike između umetnika i neumetnika u pogledu opšte kreativne sposobnosti. Sa druge strane, umetnici imaju bolje postignuće na subskali Originalnost. Dobijeni rezultati sugerišu postojanje opšte kreativne sposobnosti koja nije rezervisana samo za umetnike. Ipak, razlike u postignuću u domenu originalnosti upućuju na postojanje dominantnog načina kreativnog mišljenja u grupi umetnika.