Publications by authors named "HAVLIK M"

Article Synopsis
  • The study examines the chiral properties of nickel(II) complexes derived from various porphyrin derivatives with substituted phenyl groups.
  • Investigations into the enantioseparation of racemic mixtures were conducted using high-performance liquid chromatography (HPLC) techniques.
  • The purity and configurations of the isolated enantiomers were confirmed through HPLC, UV-Vis spectroscopy, and TDDFT calculations, revealing specific maximum molar ellipticity values.
View Article and Find Full Text PDF

In this work, two stilbene derivatives with different substituents on the phenolic core (phenyl and dimethoxyphenyl) were prepared. The fluorosolvatochromic response of their -propylated derivatives was studied in a solution of twelve different solvents using UV-Vis absorption and fluorescence emission spectra. Both stilbazolium dyes showed a significant negative solvatochromic effect, with a hypsochromic shift in the visible absorption band of approximately 232 nm and 265 nm for phenyl and the dimethoxyphenyl derivative, respectively, when the solvent was changed from water to pyridine.

View Article and Find Full Text PDF

Neuroblastoma represents 8-10 % of all malignant tumors in childhood and is responsible for 15 % of cancer deaths in the pediatric population. Aggressive neuroblastomas are often resistant to chemotherapy. Canonically, neuroblastomas can be classified according to the MYCN (N-myc proto-oncogene protein) gene amplification, a common marker of tumor aggressiveness and poor prognosis.

View Article and Find Full Text PDF

Oceans are crucial to human survival, providing natural resources and most of the global oxygen supply, and are responsible for a large portion of worldwide economic development. Although it is widely considered a silent world, the sea is filled with natural sounds generated by marine life and geological processes. Man-made underwater sounds, such as active sonars, maritime traffic, and offshore oil and mineral exploration, have significantly affected underwater soundscapes and species.

View Article and Find Full Text PDF
Article Synopsis
  • Conscious experience is a complex issue in neuroscience, with current studies struggling to pinpoint the essential neural events that lead to consciousness.
  • The existing research is mainly speculative and relies heavily on observing correlations rather than understanding the underlying mechanisms.
  • New brain stimulation techniques, like geodesic transcranial electric neuromodulation, may offer an alternative method focused on causation that could advance our understanding of how consciousness operates.
View Article and Find Full Text PDF

The reactions of 2-naphthylamine and methyl 6-amino-2-naphthoate with formalin and paraformaldehyde were studied experimentally, spectrally, and by quantum chemical calculations. It was found that neither the corresponding aminals nor imines were formed under the described conditions but could be prepared and spectrally characterized at least in situ under modified conditions. Several of the previously undescribed intermediates and by-products were isolated or at least spectrally characterized.

View Article and Find Full Text PDF

Two-dimensional nanomaterials, as one of the most widely used substrates for energy storage devices, have achieved great success in terms of the overall capacity. Despite the extensive research effort dedicated to this field, there are still major challenges concerning capacitance modulation and stability of the 2D materials that need to be overcome. Doping of the crystal structures, pillaring methods and 3D structuring of electrodes have been proposed to improve the material properties.

View Article and Find Full Text PDF
Article Synopsis
  • A series of metalloporphyrin dimers were synthesized as Tröger's bases or spiro-Tröger's bases using various substituted porphyrin derivatives.
  • The process involved converting free-base porphyrins to metalloporphyrins and nitrating them, followed by reduction to produce β-aminometalloporphyrins, which were then reacted with methanal to yield different types of Tröger's bases.
  • The yields and ratios of the products were influenced by factors such as the type of acid used, the equivalent of methanal, and the solvent, with chlorinated solvents being crucial for spiro-Tröger's base formation, confirmed through electron diffraction.
View Article and Find Full Text PDF

Reefs are biogenic structures that result in three-dimensional accumulations of calcium carbonate. Over geological timescales, a positive balance between the production and accumulation of calcium carbonate versus erosional and off-reef transport processes maintains positive net accretion on reefs. Yet, how ecological processes occurring over decadal timescales translate to the accumulation of geological structures is poorly understood, in part due to a lack of studies with detailed time-constrained chronologies of reef accretion over decades to centuries.

View Article and Find Full Text PDF

In this paper we examine how participants' multimodal conduct maps onto one of the basic organizational principles of social interaction: preference organization - and how it does so in a similar manner across five different languages (Czech, French, Hebrew, Mandarin, and Romanian). Based on interactional data from these languages, we identify a recurrent multimodal practice that respondents deploy in turn-initial position in dispreferred responses to various first actions, such as information requests, assessments, proposals, and informing. The practice involves the verbal delivery of a turn-initial expression corresponding to English 'I don't know' and its variants ('dunno') coupled with gaze aversion from the prior speaker.

View Article and Find Full Text PDF
Article Synopsis
  • The study investigates how a chemically modified stationary phase (CMSP) can be used to analyze binding abilities of compounds.
  • Three types of silica-based CMSPs are prepared and characterized for use in liquid chromatography (LC) columns, which helps estimate retention factors of specific compounds.
  • The analysis reveals that breaking down total retention into structure-specific factors provides a clearer understanding of the binding mechanisms, highlighting the limitations of relying only on total retention values.
View Article and Find Full Text PDF

Oceans have become substantially noisier since the Industrial Revolution. Shipping, resource exploration, and infrastructure development have increased the anthrophony (sounds generated by human activities), whereas the biophony (sounds of biological origin) has been reduced by hunting, fishing, and habitat degradation. Climate change is affecting geophony (abiotic, natural sounds).

View Article and Find Full Text PDF

The fluorescent probes based on Tröger's base motive with both coumarin and cyanine substitution 11-13 have been synthesized by multi-step synthesis in high overall yields. Intracellular localization of prepared probes have been tested using four different cell lines (HF-P4, BLM, U-2 OS and A-2058). Prepared probes have intensive green and red fluorescence.

View Article and Find Full Text PDF

Studies of consciousness have traditionally been based mainly upon the perceptual domains of consciousness. However, there is another side of consciousness, represented by various types of intrinsic conscious experiences. Even though intrinsic experiences can represent up to 50% of our conscious experiences, they are still largely neglected in conscious studies.

View Article and Find Full Text PDF

Four novel fluorescent cores bearing a transformable functional group based on a π-expanded naphthalimide including a fused pyranone or furan ring have been prepared. Fluorescent probes LysoSers 13-16 for lysosomal targeting have been tested. Co-localization with a commercial lysosome specific marker confirmed that the LysoSers labeled the lysosomal compartment with high selectivity.

View Article and Find Full Text PDF

A series of pentamethinium salts with benzothiazolium and indolium side units comprising one or two positive charges were designed and synthesized to determine the relationships among the molecular structure, charge density, affinity to sulfated polysaccharides, and biological activity. Firstly, it was found that the affinity of the pentamethinium salts to sulfated polysaccharides correlated with their biological activity. Secondly, the side heteroaromates displayed a strong effect on the cytotoxicity and selectivity towards cancer cells.

View Article and Find Full Text PDF

The elusive relationship between the mental domain and the physical brain, known as the mind-body problem, is still a hot topic of discussion among philosophers and neuroscientists. Rather than solving this problem, our pilot study addresses the question as to whether personality features could influence intuitions of the mind-body problem, or more precisely, whether it is possible to identify a person's intuitive inclinations toward dualism or materialism and their inclinations toward reduction of the mind to the brain. For the purposes of this pilot study, we developed a questionnaire, which employed several theories of analytic philosophy of the mind, in order to determine which category the participants would belong to.

View Article and Find Full Text PDF

Alzheimer's disease (AD) is a progressive neurodegenerative disorder affecting tens of million people. Currently marketed drugs have limited therapeutic efficacy and only slowing down the neurodegenerative process. Interestingly, it has been suggested that biometal cations in the amyloid beta (Aβ) aggregate deposits contribute to neurotoxicity and degenerative changes in AD.

View Article and Find Full Text PDF

In this review, we deal with two central questions of consciousness and , and we outline their possible future development. The question refers to the empirical endeavor to reveal the neural correlates and mechanisms that form consciousness. On the other hand, the question generally refers to the "hard problem" of consciousness, which claims that empirical science will always fail to provide a satisfactory answer to the question why is there conscious experience at all.

View Article and Find Full Text PDF

A new ion-exchanger type chiral stationary phase for high-performance liquid chromatography was prepared. The synthetic protocol is based on derivatization of silica with (3-iodopropyl)trimethoxysilane in the first step followed by immobilization of strychnine via quaternization of nitrogen atom of the alkaloid strychnine. The synthesized chiral stationary phase was chromatographically characterized.

View Article and Find Full Text PDF

The first step toward a modern understanding of fMRI resting brain activity was made by Bharat Biswal in 1995. This surprising, and at first rejected, discovery is now associated with many resting state networks, notably the famous default mode network (DMN). Resting state activity and DMN significantly reassessed our traditional beliefs and conventions about the functioning of the brain.

View Article and Find Full Text PDF

Modifications of DNA cytosine bases and histone posttranslational modifications play key roles in the control of gene expression and specification of cell states. Such modifications affect many important biological processes and changes to these important regulation mechanisms can initiate or significantly contribute to the development of many serious pathological states. Therefore, recognition and determination of chromatin modifications is an important goal in basic and clinical research.

View Article and Find Full Text PDF

Consciousness still stands as one of the most interesting and the most elusive problems of neuroscience. Finding its correlates is the first step toward its satisfactory explanation. Several theories have proposed its correlates but none of them seem to be generally accepted even though most of them share some very similar elements.

View Article and Find Full Text PDF

The development of novel diagnostic tools is a primary goal in bioanalytical chemistry. Here we report the synthesis of Tröger's base functionalized with amino- and coumarin-units designed as a monomeric unit for the development of an electrochemical cancer sensor. The synthesized receptor was deposited onto a conducting support using electrochemical polymerization, characterized spectroscopically and tested potentiometrically towards metabolites used as tumor markers of neuroblastoma.

View Article and Find Full Text PDF

The tris-Tröger's bases (TBs) are electron-rich fluorescent concave receptors due to the incorporation of naphthalene or triphenylene moieties (calix-1 and calix-2). The structures of the TBs were studied using SXRD to reveal the propensity to bind nitroaromatics. Titration with explosive-related nitro-compounds suggests that the TBs may be used for sensing explosives.

View Article and Find Full Text PDF