This research focuses on non-Newtonian stagnation-bioconvective point flow near a stretched cylinder along the Reiner-Rivlin model. The study incorporates thermal and mass transfers, considering thermodynamic diffusion, bioconvection, and viscous heating. Entropy production analysis is included to assess the inherent uncertainty in transport processes. The computational framework is developed under prescribed wall temperature and concentration conditions, which are essential for achieving self-similar solutions. Numerical findings are collected using MATLAB's "bvp4c" technique. The numerical outcomes are validated by comparing them with solutions for specific parameter values. The impact of curvature on boundary layer behavior is investigated for a range of governing parameters. For Reiner-Rivlin fluids, the skin friction coefficient is calculated to determine the force exerted by the straining cylinder. Additionally, a rise in the Reiner-Rivlin fluid factor causes a reduction in the surface cooling rate. Mainly the flow patterns observed by considering the quantity of parameters as [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] on all profiles.

• Klíčová slova
• Deforming cylinder, Entropy generations, Reiner–Rivlin model, Stagnation-point bioconvective flow, Thermal and mass transmissions, Viscous dissipation,
• Publikační typ
• časopisecké články MeSH

Hydrodynamic data, i.e. intrinsic viscosity and sedimentation coefficient, for denatured globular proteins in 6 M guanidinium chloride have been re-analysed in terms of the Yamakawa-Fujii theory of the wormlike cylinder model. Molecular parameters thus obtained ((mean value of R2 0/M) infinity, the Kuhn statistical segment length and the molecular weight per unit contour length) are in better agreement with the values obtained theoretically or by other methods than those evaluated on the basis of the model of non-draining random coil.

• MeSH
• denaturace proteinů * MeSH
• konformace proteinů * MeSH
• matematika MeSH
• modely strukturální * MeSH
• proteiny chemie   MeSH
• viskozita MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• proteiny MeSH

We present a dissipative particle dynamics simulation study on nanostructure formation of symmetric and asymmetric diblock copolymers confined between planar surfaces. We consider symmetric and slightly asymmetric diblock copolymers that form lamellar nanostructures in the bulk, and highly asymmetric diblock copolymers that form cylindrical nanostructures in the bulk. The formation of the diblock copolymer nanostructures confined between the planar surfaces is investigated and characterized by varying the separation width and the strength of the interaction between the surfaces and the diblock copolymers. Both the slit width and the surface interaction strongly influence the phase diagram, especially for the asymmetric systems. For the symmetric and slightly asymmetric diblock copolymer systems, the confinement primarily affects the orientation of the lamellar domains and only marginally influences the domain morphologies. These systems form parallel lamellar phases with different number of lamellae, and perpendicular and mixed lamellar phases. In a narrow portion of the phase diagram, these systems exhibit a parallel perforated lamellar phase, where further insight into the appearance of this phase is provided through free-energy calculations. The confined highly asymmetric diblock copolymer system shows, in addition to nanostructures with parallel and perpendicular cylinders, noncylindrical structures such as parallel lamellae and parallel perforated lamellae. The formation of the various confined nanostructures is further analyzed by calculating structural characteristics such as the mean square end-to-end distance of the diblock copolymers and the nematic order parameter.

• Publikační typ
• časopisecké články MeSH

Piezoelectric transducers are used as a sensing device to study the fluids' motion. Moreover, they are used as a harvester of energy of Flow-Induced Vibration (FIV). The current FIV harvesters in the literature rely on piezoelectric cantilevers coupled with a bluff body that creates flow instabilities. This paper studies the use of piezoelectric cylinders as a novel transducer in the field of fluid mechanics, where the transducer makes use of its bluff geometry to create instability. The study was based on wind tunnel measurements performed on four piezoelectric cylinders of different sizes over a speed range of 1-7 m/s. The paper looks at the variation of the generated voltage across the Reynolds number. It also compares the spectra of the generated open-circuit voltage to the turbulence spectra features known from the literature.

• Klíčová slova
• cylinder wake, energy harvesting, flow-induced vibration, piezoelectric sensors, vortex shedding,
• Publikační typ
• časopisecké články MeSH

Alternative DNA structures play critical roles in fundamental biological processes linked to human diseases. Thus, targeting and stabilizing these structures by specific ligands could affect the progression of cancer and other diseases. Here, we describe, using methods of molecular biophysics, the interactions of two oxidatively locked [Co2L3]6+ cylinders, rac-2 and meso-1, with diverse alternative DNA structures, such as junctions, G quadruplexes, and bulges. This study was motivated by earlier results demonstrating that both Co(III) cylinders exhibit potent and selective activity against cancer cells, accumulate in the nucleus of cancer cells, and prove to be efficient DNA binders. The results show that the bigger cylinder rac-2 stabilizes all DNA structures, while the smaller cylinder meso-1 stabilizes just the Y-shaped three-way junctions. Collectively, the results of this study suggest that the stabilization of alternative DNA structures by Co(III) cylinders investigated in this work might contribute to the mechanism of their biological activity.

• Klíčová slova
• Alternative DNA structures, Cobalt helicates, DNA G-quadruplexes, DNA bulges, DNA junctions,
• MeSH
• DNA * chemie   metabolismus   MeSH
• G-kvadruplexy MeSH
• kobalt * chemie   MeSH
• komplexní sloučeniny chemie   farmakologie   MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The interaction of metallosupramolecular cylinders with DNA three-way junctions has been studied by gel electrophoresis. A recent X-ray crystal structure of a palindromic oligonucleotide forming part of a complex with such a cylinder revealed binding at the heart of a three-way junction structure. The studies reported herein confirm that this is not solely an artefact of crystallisation and reveal that this is a potentially very powerful new mode of DNA recognition with wide scope. The cylinders are much more effective at stabilizing three-way junctions than simple magnesium di-cations or organic or metallo-organic tetra-cations, with the M cylinder enantiomer being more effective than P. The recognition is not restricted to three-way junctions formed from palindromic DNA with a central AT step at the junction; non-palindromic three-way junctions and those with GC steps are also stabilised. The cylinder is also revealed to stabilise other Y-shaped junctions, such as that formed at a fraying point in duplex DNA (for example, a replication fork), and other DNA three-way junction structures, such as those containing unpaired nucleotides, perhaps by opening up this structure to access the central cavity.

• MeSH
• DNA chemie   MeSH
• elektroforéza v polyakrylamidovém gelu metody   MeSH
• konformace nukleové kyseliny * MeSH
• kovy chemie   MeSH
• krystalografie rentgenová MeSH
• molekulární modely MeSH
• sekvence nukleotidů MeSH
• spektrofotometrie ultrafialová MeSH
• stereoizomerie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• kovy MeSH

[Fe(2)L(3)](4+) (L = C(25)H(20)N(4)) is a synthetic tetracationic supramolecular cylinder (with a triple helical architecture) that targets the major groove of DNA and can bind to DNA Y-shaped junctions. To explore the DNA-binding mode of [Fe(2)L(3)](4+), we examine herein the interactions of pure enantiomers of this cylinder with DNA by biochemical and molecular biology methods. The results have revealed that, in addition to the previously reported bending of DNA, the enantiomers extensively unwind DNA, with the M enantiomer being the more efficient at unwinding, and exhibit preferential binding to regular alternating purine-pyrimidine sequences, with the M enantiomer showing a greater preference. Also, interestingly, the DNA binding of bulky cylinders [Fe(2)(L-CF(3))(3)](4+) and [Fe(2)(L-Ph)(3)](4+) results in no DNA unwinding and also no sequence preference of their DNA binding was observed. The observation of sequence-preference in the binding of these supramolecular cylinders suggests that a concept based on the use of metallosupramolecular cylinders might result in molecular designs that recognize the genetic code in a sequence-dependent manner with a potential ability to affect the processing of the genetic code.

• MeSH
• deoxyribonukleasa I MeSH
• DNA footprinting MeSH
• DNA chemie   metabolismus   MeSH
• ethidium chemie   MeSH
• kompetitivní vazba MeSH
• konformace nukleové kyseliny MeSH
• pyridiny chemie   MeSH
• restrikční enzymy metabolismus   MeSH
• sekvence nukleotidů MeSH
• stereoizomerie MeSH
• superhelikální DNA chemie   MeSH
• železnaté sloučeniny chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• deoxyribonukleasa I MeSH
• DNA MeSH
• ethidium MeSH
• pyridiny MeSH
• restrikční enzymy MeSH
• superhelikální DNA MeSH
• železnaté sloučeniny MeSH

We study bridging transitions between spherically and cylindrically shaped particles (colloids) of radius R separated by a distance H that are dissolved in a bulk fluid (solvent). Using macroscopics, microscopic density-functional theory, and finite-size scaling theory, we study the location and order of the bridging transition and also the stability of the liquid bridges, which determines spinodal lines. The location of the bridging transitions is similar for cylinders and spheres, so that at bulk coexistence, for example, the distance H_{b} at which a transition between bridged and unbridged configurations occurs is proportional to the colloid radius R. However, all other aspects, particularly the stability of liquid bridges, are very different in the two systems. Thus, for cylinders the bridging transition is typically strongly first-order, while for spheres it may be first-order, critical, or rounded as determined by a critical radius R_{c}. The influence of thick wetting films and fluctuation effects beyond mean field are also discussed in depth.

• Publikační typ
• časopisecké články MeSH

PURPOSE: We usually use objective and subjective methods for examination of the eye astigmatism in optometry, respectively ophthalmology. Objective methods enable to measure sphere-cylindrical refraction of the eye. If we want to prescribe new glasses or contact lenses we usually use subjective methods. The aim of this study was to measure sensitivity and specificity of some subjective and objective methods for examination of the eye astigmatism. We supposed that automatic objective refraction will be the most exact method so we choose this method as the reference method. For comparison we chose subjective methods Jackson crossed cylinders (JCC), fogging method (FM) and objective method Spot Vision Screener (SVS, WelschAllyn). MATERIALS AND METHODS: We had in total 30 subjects with average age 23 years (SD 1 year) in our study. We made each measurement per eye separately and it was independent measurement so we could use measurement from each eye (n = 60). Each eye was firstly measured by subjective method FM, followed by JCC method and finally was use objective method Spot Vision Screener (SVS, WelschAllyn). Measurement with objective instrument TRK-1P (TOPCON) was use as reference measurement. The significance level was set at p = 0.05. RESULTS: In variable FM we measured sensitivity 76.2 % and specificity 66.7 %. Criterion for positive finding was -0.25 D. Result was statistically significant on level p < 0.001. In variable JCC we measured sensitivity 95.2 % and specificity 66.7 %. Criterion for positive finding was -0.25 D. Result was statistically significant on level p < 0.001. In variable SVS we measured sensitivity 47.6 % and specificity 94.4 %. Criterion for positive finding was -0.75 D. Result was statistically significant on level p < 0.001. Direct comparison of all methods showed statistically important difference between techniques JCC and FM (p = 0.0095). In other method we did not find statistically important difference (FM vs. SVS, p = 0.526 and JCC vs. SVS, p = 0.105). CONCLUSION: All subjective and objective techniques were statistically significant in detection of eye astigmatism. Comparison of ROC curves showed statistically significant difference between FM and JCC technique. The JCC method showed the highest sensitivity, whereas SVS highest specificity.

• Klíčová slova
• Jackson crossed cylinder, Subjective refraction, fogging method, objective refraction, sensitivity, specificity,
• MeSH
• astigmatismus * diagnóza   MeSH
• brýle MeSH
• dospělí MeSH
• kontaktní čočky * MeSH
• lidé MeSH
• mladý dospělý MeSH
• refrakce oka MeSH
• zrakové testy MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• Publikační typ
• časopisecké články MeSH

Metallosupramolecular chemistry was used to design a new class of synthetic agents, namely, tetracationic supramolecular cylinders, that bind strongly and noncovalently in the major groove of DNA. To gain additional information on interactions of the cylinders with DNA we explored DNA unwinding and sequence-specific binding properties, as well as DNA photonuclease activity of ruthenium(II) metallosupramolecular cylinder [Ru(2)L(3)](4+), where L is a bis-pyridylimine ligand. We found that [Ru(2)L(3)](4+) unwinds negatively supercoiled plasmid DNA and exhibits binding preference to regular alternating purine-pyrimidine sequences in a similar way to the [Fe(2)L(3)](4+) analogue. Photocleavage studies showed that, unlike [Fe(2)L(3)](4+), [Ru(2)L(3)](4+) induces single-strand breaks on irradiation by visible and UVA light and cleaves DNA mainly at guanine residues contained preferentially in regularly alternating purine-pyrimidine nucleotides. As [Ru(2)L(3)](4+) binds and cleaves DNA in a sequence-dependent manner, it may provide a useful tool for basic and applied biology, such as for controlled manipulation of the genome.

• MeSH
• DNA chemie   metabolismus   MeSH
• ethidium MeSH
• fotochemie MeSH
• ligandy MeSH
• molekulární modely MeSH
• molekulární sekvence - údaje MeSH
• plazmidy chemie   metabolismus   MeSH
• sekvence nukleotidů MeSH
• sloučeniny ruthenia chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• ethidium MeSH
• ligandy MeSH
• sloučeniny ruthenia MeSH