circularity
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The phenomenological point of view of the body is usually appreciated for having introduced the notion of the ‘lived' body. We cannot merely analyze and explain the body as one of the elements of the world of objects. We must also describe it, for example, as the center of our perspective on the world, the place where our sensing is ‘localized', the agens which directly executes our intentions. However, in Husserl, the idea of the body as lived primarily complements his objectivism: the body (Leib) is an objective and mental reality, a ‘double unity', as he writes. In contrast, Merleau-Ponty's later considerations of the body in Phenomenology of Perception tend to the idea of a circular relationship between the objective and subjective dimensions of the body – between the objective and the lived. One of the means to overcome the idea of the body as a site of the correlation between two opposite and complementary realms is, for Merleau-Ponty, the philosophical interpretation of an early neurological notion of ‘body schema'. Body schema is neither an idea nor a physiological-physical fact, it is rather a practical diagram of our relationships with the world, an action-based norm in reference to which things make sense. In the recently published preparatory notes for his 1953 courses, Merleau-Ponty dedicates much effort to further developing the notion of body schema, and interprets fresh sources that he did not use in Phenomenology of Perception. Notably, he studies various possibilities of how this practical ‘diagram' can be de-differentiated (pathology) or further refined (cognitive and cultural superstructures, symbolic systems), which shows the fundamentally dynamic unity of the body. This paper summarizes the basic elements of Merleau-Ponty's 1953 renewed philosophical interpretation of the notion of body schema, while contrasting it to the more traditional understanding of the body in phenomenology and in recent philosophical texts dealing with body schema.
- MeSH
- filozofie MeSH
- lidé MeSH
- percepce fyziologie MeSH
- představa o vlastním těle * MeSH
- sebepojetí MeSH
- sebezhodnocení (psychologie) MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
Magnetic circular dichroism (MCD) spectroscopy has been established as a convenient method to study electronic structure, in particular for small symmetric organic molecules. Newer applications on more complex systems are additionally stimulated by the latest availability of precise quantum-chemical techniques for the spectral simulations. In this work, a sum over states (SOS) summation is reexamined as an alternative to the derivative techniques for the MCD modeling. Unlike in previous works, the excited electronic states are calculated by the time-dependent density functional theory (TDDFT). A gradient formulation of the MCD intensities is also proposed, less dependent on the origin choice than the standard expressions. The dependencies of the results on the basis set, number of electronic states, and coordinate origin are tested on model examples, including large symmetric molecules with degenerate electronic states. The results suggest that the SOS/TDDFT approach is a viable and accurate technique for spectral simulation. It may even considerably reduce the computational time, if compared with the traditional MCD computational procedures based on the response theory.
Circular dichroism (CD) is remarkably sensitive to the conformational states of nucleic acids; therefore, CD spectroscopy has been used to study most features of DNA and RNA structures. Quadruplexes are among the significant noncanonical nucleic acids architectures that have received special attentions recently. This article presents examples on the contribution of CD spectroscopy to our knowledge of quadruplex structures and their polymorphism. The examples were selected to demonstrate the potential of this simple method in the quadruplex field. As CD spectroscopy detects only the global feature of a macromolecule, it should preferably be used in combination with other techniques. On the other hand, CD spectroscopy, often as a pioneering approach, can reveal the formation of particular structural arrangements, to search for the conditions stabilizing the structures, to follow the transitions between various structural states, to explore kinetics of their appearance, to determine thermodynamic parameters and also detect formation of higher order structures. This article aims to show that CD spectroscopy is an important complementary technique to NMR spectroscopy and X-ray diffraction in quadruplex studies.
- MeSH
- cirkulární dichroismus metody MeSH
- difrakce rentgenového záření MeSH
- DNA chemie MeSH
- G-kvadruplexy * MeSH
- guanin chemie MeSH
- kinetika MeSH
- konformace nukleové kyseliny * MeSH
- oligonukleotidy chemie MeSH
- termodynamika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Lung cancer is one of the main causes of cancer-related death in the world, especially due to its frequency and ineffective therapeutically approaches in the late stages of the disease. Despite the recent advent of promising new targeted therapies, lung cancer diagnostic strategies still have difficulty in identifying the disease at an early stage. Therefore, the characterizations of more sensible and specific cancer biomarkers have become an important goal for clinicians. Circular RNAs (circRNAs), a type of RNA with covalently closed continuous loop structures that display high structural resistance and tissue specificity pointed toward a potential biomarker role. Current investigations have identified that circRNAs have a prominent function in the regulation of oncogenic pathways, by regulating gene expression both at transcriptional and post-transcriptional level. The aim of this review is to provide novel information regarding the implications of circRNAs in lung cancer, with an emphasis on the role in disease development and progression. Initially, we explored the potential utility of circRNAs as biomarkers, focusing on function, mechanisms, and correlation with disease progression in lung cancer. Further, we will describe the interaction between circRNAs and other non-coding species of RNA (particularly microRNA) and their biological significance in lung cancer. Describing the nature of these interactions and their therapeutic potential will provide additional insight regarding the altered molecular landscape of lung cancer and consolidate the potential clinical value of these circular transcripts. This article is categorized under: RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.
- MeSH
- cílená molekulární terapie MeSH
- kruhová RNA chemie genetika MeSH
- lidé MeSH
- nádorové biomarkery * MeSH
- nádory plic farmakoterapie genetika metabolismus patologie MeSH
- regulace genové exprese u nádorů * MeSH
- RNA interference MeSH
- signální transdukce MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Circular RNAs (circRNAs) constitute a recently recognized group of noncoding transcripts that function as posttranscriptional regulators of gene expression at a new level. Recent developments in experimental methods together with rapidly evolving bioinformatics approaches have accelerated the exploration of circRNAs. The differentiation of hematopoietic stem cells into a broad spectrum of specialized blood lineages is a tightly regulated process that depends on a multitude of factors, including circRNAs. However, despite the growing number of circRNAs described to date, the roles of the majority of them in hematopoiesis remain unknown. Given their stability and disease-specific expression, circRNAs have been acknowledged as novel promising biomarkers and therapeutic targets. In this paper, the biogenesis, characteristics, and roles of circRNAs are reviewed with an emphasis on their currently recognized or presumed involvement in hematopoiesis, especially in acute myeloid leukemia and myelodysplastic syndrome.
- MeSH
- akutní myeloidní leukemie krev genetika MeSH
- hematopoéza * MeSH
- kruhová RNA krev genetika MeSH
- lidé MeSH
- myelodysplastické syndromy krev genetika MeSH
- nádorové biomarkery krev genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
The optical activity in porphyrins can easily be induced by a chiral environment, but it is difficult to determine the underlying mechanisms purely on an experimental basis. Therefore, in this study, magnitudes of the perturbational, dipolar, and direct covalent contributions to the electronic circular dichroism (CD) are evaluated with the aid of quantum chemical computations. Electronic properties of model porphyrin chromophores are analyzed. Time-dependent density functional theory (TD DFT), particularly with the hybrid B3LYP functional, appeared suitable for estimation of the electronic excitation energies and spectral intensities. The transition dipole coupling (TDC) between chirally stacked porphyrins was determined as the most important mechanism contributing to their optical activity. This is in agreement with previous experimental observations, where chiral matrices often induce the stacking and large CD signals. About a 10 times smaller signal could be achieved by a chiral orientation of the phenyl or similar residues covalently attached to the porphyrin core. Also, this prediction is in agreement with known experiments. Perturbation models realized by a chirally arranged porphyrin and a point charge, or by a porphyrin and the methane molecule, provided the smallest CD signals. The electrically neutral methane induced similar CD magnitudes as those of the charge, but spectral shapes were different. For a complex of porphyrin and the alanine cation, a significant influence of the solvent on the resultant CD spectral shape was observed, while for the charge and methane perturbations, a negligible solvent effect was found. Detailed dependence of the induced optical activity on variations of geometrical parameters is discussed. The simulations of the induced porphyrin activity can thus bring important information about the structure and intermolecular interactions in chiral complexes.
Východiska: Spinocelulární karcinom dutiny ústní (oral squamous cell carcinoma – OSCC) je nejběžnějším typem zhoubných nádorů v oblasti hlavy a krku. Je známo, že cirkulární RNA (circRNA) hraje důležitou roli v karcinogenezi různých typů zhoubných nádorů. Role circRNA při OSCC však zůstává nejasná. Materiál a metody: Byly získány tkáně OSCC a přilehlé normální tkáně k detekci exprese circRNA sekvenováním nové generace (next generation sequencing – NGS) a byly vybrány tkáně OSCC k ověření circRNAs různého významu pomocí kvantitativní polymerázové řetězové reakce s reverzní transkriptázou (reverse transcriptase-quantitative polymerase chain reaction – RT-qPCR). Pro další zkoumání role hsa-circ-0006203 – hsa-circ-0004872 byl vytvořen design primeru a byla provedena RT-PCR. Hladiny exprese byly detekovány pomocí RT-qPCR. Výsledky: Výsledky NGS ukázaly, že u OSCC byly výrazně exprimovány circRNA, přičemž dvě circRNAs byly exprimovány výrazně odlišným způsobem. hsa-circ-0006203 – hsa-circ-0004872 byly ve vzorcích tkáně OSCC výrazně downregulována, což statisticky korelovalo s jejich patologickou diferenciací. Závěr: Souhrnně lze říci, že výsledky prezentované studie odhalily zvýšené množství circRNA ve tkáních OSCC a pokud je nám známo, náš tým jako první zkoumal regulační roli sítě hsa-circ-0006203 – hsa-circ-0004872 u OSCC. Výsledky ukázaly, že hsa-circ-0006203 – hsa-circ-0004872 může být případným biomarkerem OSCC.
Background: Oral squamous cell carcinoma (OSCC) is the most common cancer of the head and neck region. The circular RNA (circRNA) is known to serve an important role in the carcinogenesis of different types of cancer. However, the circRNA role of OSCC remains unclear. Material and methods: OSCC tissues and adjacent normal tissues were obtained to detect circRNAs expression by the next generation sequencing (NGS), and OSCC tissues were selected to verify the differentially significant circRNAs by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). To further investigate the role of hsa-circ-0006203 – hsa-circ-0004872, the primer design and RT-PCR were performed. The expression levels were detected by RT-qPCR. Results: The NGS results demonstrated that circRNAs were abundantly expressed in OSCC, and two circRNAs were significantly differentially expressed. hsa-circ-0006203 – hsa-circ-0004872 were significantly downregulated in OSCC tissue samples and was statistically correlated with pathological differentiation. Conclusion: In summary, the results of the present study revealed that OSCC tissues have abundant circRNAs and, to the best of our knowledge, it was our team who firstly explore the regulatory role of the hsa-circ-0006203 – hsa-circ-0004872 network in OSCC. The results indicated that hsa-circ-0006203 – hsa-circ-0004872 may be a potential biomarker for OSCC.
- Klíčová slova
- hsa-circ-0006203, hsa-circ-0004872,
- MeSH
- klinická studie jako téma MeSH
- kruhová RNA MeSH
- lidé MeSH
- nádorové biomarkery MeSH
- nádory úst * diagnóza genetika MeSH
- Check Tag
- lidé MeSH