Publications by authors named "Mikac U"

Polymer matrix tablets are an important drug-delivery system widely used for oral drug administration. Understanding the tablet hydration process, both experimentally and theoretically, is, thus, very important for the development of drug delivery systems that exhibit high drug loading capacity and controlled release potential. In this study, we used magnetic resonance microscopy (MRM) to nondestructively and dynamically analyze the water hydration process of xanthan-based tablets.

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Expression of CD40 and CD192 markers in different monocyte subpopulations has been reported to be altered in people with MS (pwMS). Also, functional connectivity of the corticospinal motor system pathway alterations has been proved by transcranial magnetic stimulation (TMS). The study objective was to investigate the expression of CD40 and CD192 in classical (CD14CD16), intermediate CD14CD16 and non-classical (CD14CD16) blood monocyte subpopulations in pwMS, undergoing neurophysiological TMS assessment of the corticospinal tract integrity by recording motor-evoked potentials (MEPs).

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Probing the cortic ospinal tract integrity by transcranial magnetic stimulation (TMS) could help to understand the neurophysiological correlations of multiple sclerosis (MS) symptoms. Therefore, the study objective was, first, to investigate TMS measures (resting motor threshold-RMT, motor evoked potential (MEP) latency, and amplitude) of corticospinal tract integrity in people with relapsing-remitting MS (pwMS). Then, the study examined the conformity of TMS measures with clinical disease-related (Expanded Disability Status Scale-EDSS) and magnetic resonance imaging (MRI) results (lesion count) in pwMS.

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Pregnancy often triggers anxiety and health concerns in women, leading many to search for health information online. Excessive, compulsive, and repetitive online health research, accompanied by heightened anxiety, can result in cyberchondria. This study aimed to explore the risk factors, triggers, and outcomes of cyberchondria in pregnant women.

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The anti-scientific and anti-vaccine movements gained momentum amidst the health and socio-economic crisis brought about by the COVID-19 pandemic. These widespread pseudoscientific beliefs and the endorsement of conspiracy theories likely contributed to the COVID-19 vaccine hesitancy. The aim of this study was to explore which variables best differentiated between groups of vaccinated (n = 289), vaccine-hesitant (n = 106), and vaccine-refusing (n = 146) young adults.

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Clinically oriented studies of mood as a function of the menstrual cycle mainly address the negative moods in the premenstrual phase of the cycle. However, a periovulatory increase in positive emotions and motivations related to reproduction has also been noted. Thus, it has been suggested that the drop in mood during the luteal phase of the menstrual cycle might be a byproduct of elevated positive moods occurring mid-cycle.

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Nano-dimensional materials have become a focus of multiple clinical applications due to their unique physicochemical properties. Magnetic nanoparticles represent an important class of nanomaterials that are widely studied for use as magnetic resonance (MR) contrast and drug delivery agents, especially as they can be detected and manipulated remotely. Using magnetic cobalt ferrite spinel (MCFS) nanoparticles, this study was aimed at developing a multifunctional drug delivery platform with MRI capability for use in cancer treatment.

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Sleep disturbances and poor sleep are a common complaint in the population with multiple sclerosis (MS) disease. The most commonly reported scale is the Pittsburgh Sleep Quality Index (PSQI), measuring seven components of sleep quality. Yet, till today, the PSQI instrument has not been validated in people with multiple sclerosis (pwMS).

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Wood is a widely used material because it is environmentally sustainable, renewable and relatively inexpensive. Due to the hygroscopic nature of wood, its physical and mechanical properties as well as the susceptibility to fungal decay are strongly influenced by its moisture content, constantly changing in the course of everyday use. Therefore, the understanding of the water state (free or bound) and its distribution at different moisture contents is of great importance.

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The global epidemic of (mis)information, spreading rapidly via social media platforms and other outlets, can be a risk factor for the development of anxiety disorders among vulnerable individuals. Cyberchondria can be a vulnerability factor for developing anxiety in a pandemic situation, particularly when the Internet is flooded with (mis)information. The aim of our study was to examine how cyberchondria is related to changes in levels of COVID-19 concern and safety behaviours among persons living in Croatia during the period in which the first COVID-19 case was identified and when the country recorded its first fatality.

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Hydrophilic matrix tablets with controlled drug release have been used extensively as one of the most successful oral drug delivery systems for optimizing therapeutic efficacy. In this work, magnetic resonance imaging (MRI) is used to study the influence of various pHs and mechanical stresses caused by medium flow (at rest, 80, or 150 mL/min) on swelling and on pentoxifylline release from xanthan (Xan) tablets. Moreover, a bimodal MRI system with simultaneous release testing enables measurements of hydrogel thickness and drug release, both under the same experimental conditions and at the same time.

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This article describes the designing of matrix tablets composed of polyethylene oxides (PEOs) with relative molecular masses of 1 × 106, 2 × 106, and 4 × 106. Percolation thresholds were determined for all of the selected PEO formulations (18, 16, and 12 %, m/m), taking into consideration excipients and tablet surface area which significantly increased the percolation threshold. Moreover, the robustness of the gel layer in PEO matrix tablets was evaluated by magnetic resonance imaging under various mechanical stresses (no flow, 12 mL min-1, and 64 mL-1 of medium flow).

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Three-dimensional (3D) magnetic resonance microscopy (MRM) is a modality of magnetic resonance imaging (MRI) optimized for the best resolution. Metamorphosis of the Carniolan worker honey bee () was studied under controlled temperature and humidity conditions from sealed larvae until the emergence of an adult. The 3D images were analyzed by volume rendering and segmentation, enabling the analysis of the body, tracheal system and gastrointestinal tract through the time course of volume changes.

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The dynamic properties of water and polymer molecules in xanthan hydrogels at different polymer mass fractions were investigated through the combination of conventional and fast-field cycling NMR relaxation to obtain the information about dynamics in different time scales. The results showed that water dynamics were faster in diluted than in concentrated hydrogels. However, the type of polymer-chain dynamics did not change for xanthan fractions from 0.

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Number of NMR/MRI studies on batteries is rapidly increasing in the past decade. As the test batteries designed for the studies contain metal parts such as electrodes and lead wires as well as other conductive parts (electrolyte), which all present obstacles for good MR signal reception, understanding of the role of battery design and of battery interactions with magnetic field is of a key importance for a successful performance of the experiments. For the study, five different samples mimicking a real battery cell were made.

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Digit ratio (2D:4D) and facial width-to-height ratio (WHR) are supposedly static indicators of testosterone exposition during prenatal and pubertal lifetime, respectively. Both measures have been linked to aggressive and assertive behavior in laboratory economic games, as well as in real world scenarios. Most of the research-often limited to male subjects-considers the associations between these behaviors, traits, and hormonal markers separately for 2D:4D and WHR.

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The formation of a gel coat around xanthan (Xan) tablets, empty or loaded with pentoxifylline (PF), and its release in media differing in pH and ionic strength by NMR, MR imaging, and two release methods were studied. The T1 and T2 NMR relaxation times in gels depend predominantly on Xan concentration; the presence of PF has negligible influence on them. It is interesting that the matrix swelling is primarily regulated by Xan despite high drug loading (25%, 50%).

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Magnetic resonance microscopy (MRM) was used to study water distribution and mobility in common bean (Phaseolus vulgaris) seed during soaking at room temperature (20°C) and during the cooking of presoaked and dry bean seed in near-boiling water (98°C). Two complementary MRI methods were used to determine the total water uptake into the seed: the T2-weighted 3D RARE method, which yielded an increased signal from regions of highly mobile (bulk) water and a suppressed signal from regions of poorly mobile (bound) water; and the 3D SPI method, which yielded an increased signal from regions of water restricted in motion and a suppressed signal from the bulk water regions owing to the short repetition time of the method. Based on these results, it can be concluded that during soaking water enters the bean through the micropyle, migrating below the seed coat.

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Cathepsin B (CtsB) is a lysosomal cysteine proteinase that is specifically translocated to the extracellular milieu during cancer progression. The development of a lipidated CtsB inhibitor incorporated into the envelope of a liposomal nanocarrier (LNC-NS-629) is described. Ex vivo and in vivo studies confirmed selective targeting and internalization of LNC-NS-629 by tumor and stromal cells, thus validating CtsB targeting as a highly promising approach to cancer diagnosis and treatment.

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Modified-release matrix tablets have been extensively used by the pharmaceutical industry as one of the most successful oral drug-delivery systems. The key element in drug release from hydrophilic matrix tablets is the gel layer that regulates the penetration of water and controls drug dissolution and diffusion. Magnetic resonance imaging (MRI) is a powerful, non-invasive technique that can help improve our understanding of the gel layer formed on swellable, polymer-matrix tablets, as well as the layer's properties and its influence on the drug release.

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The tumour microenvironment regulates tumour progression and the spread of cancer in the body. Targeting the stromal cells that surround cancer cells could, therefore, improve the effectiveness of existing cancer treatments. Here, we show that magnetic nanoparticle clusters encapsulated inside a liposome can, under the influence of an external magnet, target both the tumour and its microenvironment.

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Introduction: Magnetic resonance imaging is a powerful, non-invasive technique that can help improve our understanding of the hydrogel layer formed on swellable, polymer-matrix tablets, as well as the layer's properties and its influence on drug release.

Areas Covered: In this paper, the authors review the NMR and MRI investigations of hydrophilic, swellable polymers published since 1994. The review covers NMR studies on the properties of water and drugs within hydrated polymers.

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The key element in drug release from hydrophilic matrix tablets is the gel layer that regulates the penetration of water and controls drug dissolution and diffusion. We have selected magnetic resonance imaging (MRI) as the method of choice for visualizing the dynamic processes occurring during the swelling of xanthan tablets in a variety of media. The aims were (i) to develop a new method using MRI for accurate determination of penetration, swelling and erosion fronts, (ii) to investigate the effects of pH and ionic strength on swelling, and (iii) to study the influence of structural changes in xanthan gel on drug release.

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The aim of the study was a comparison of 2 novel macromolecular contrast agents, Gadomer-17 and Polylysine-Gd-DTPA, with commercially available Gd-DTPA in determining the quality of tumor microvasculature by dynamic contrast enhanced MRI. Three groups of 5 mice with SA-1 tumors were studied. To each group of animals one contrast agent was administered; i.

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