Self-organization principles in the formation of multiporphyrin complexes and "semiconductor quantum dot-porphyrin" nanoassemblies

In this paper, we review several aspects of molecular recognition (based on non-covalent binding interactions) occurring between meso-pyridyl substituted tetrapyrrole extra-ligands and chemical dimers of tetrapyrrolic macrocycles containing central Zn ions and spacers of various nature and flexibility. Experimental results obtained by us earlier are analyzed using a novel approach (based on steady-state absorption/fluorescence measurements) for the evaluation of complexation constants KC for the formation of porphyrin triads. It was found that KC values [ KC ~ (0.5 – 70) × 106 M-1] show noticeable dependence on the structural parameters of the interacting subunits as well as on the solvent nature. The same self-assembly approach has been used to attach meso-pyridyl substituted porphyrins to the surface of semiconductor CdSe / ZnS quantum dots (QD). It was comparatively found that in contrast to self-assembled porphyrin triads, the formation of "QD-porphyrin" nanoassemblies takes place in competition with surface stabilizing tri-n-octyl phosphine oxide (TOPO) ligand molecules and attached porphyrin molecules. It manifests in a temporal dynamics of QD photoluminescence caused by ligand exchange, TOPO layer reorganization, QD surface reconstruction, solvent properties. It was shown that the sensitivity of QD surface morphology to attached organic ligands (e.g. porphyrins) provides an opportunity to control the dynamics and pathways of the exciton relaxation in "QD-dye" nanoassemblies by changing the structure and electronic properties of these ligands.

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Langfristige Entwicklung von zwei Waldgesellschaften im Białowieża-Urwald

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2008.0080 ◽

2008 ◽

Vol 159 (4) ◽

pp. 80-90 ◽

Cited By ~ 3

Author(s):

Bogdan Brzeziecki ◽

Feliks Eugeniusz Bernadzki

Keyword(s):

Species Composition ◽

Tree Species ◽

Stand Structure ◽

Temporal Dynamics ◽

Structural Parameters ◽

Forest Communities ◽

Natural Forests ◽

Tree Species Composition ◽

Strong Trend ◽

Long Term Study

The results of a long-term study on the natural forest dynamics of two forest communities on one sample plot within the Białowieża National Park in Poland are presented. The two investigated forest communities consist of the Pino-Quercetum and the Tilio-Carpinetum type with the major tree species Pinus sylvestris, Picea abies, Betula sp., Quercus robur, Tilia cordata and Carpinus betulus. The results reveal strong temporal dynamics of both forest communities since 1936 in terms of tree species composition and of general stand structure. The four major tree species Scots pine, birch, English oak and Norway spruce, which were dominant until 1936, have gradually been replaced by lime and hornbeam. At the same time, the analysis of structural parameters indicates a strong trend towards a homogenization of the vertical stand structure. Possible causes for these dynamics may be changes in sylviculture, climate change and atmospheric deposition. Based on the altered tree species composition it can be concluded that a simple ≪copying≫ (mimicking) of the processes taking place in natural forests may not guarantee the conservation of the multifunctional character of the respective forests.

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Novel Iodinated Hydrazide-hydrazones and their Analogues as Acetyl- and Butyrylcholinesterase Inhibitors

Current Topics in Medicinal Chemistry ◽

10.2174/1568026620666200819155503 ◽

2020 ◽

Vol 20 (23) ◽

pp. 2106-2117

Author(s):

Martin Krátký ◽

Šárka Štěpánková ◽

Michaela Brablíková ◽

Katarína Svrčková ◽

Markéta Švarcová ◽

...

Keyword(s):

Biological Activities ◽

Structural Parameters ◽

Covalent Binding ◽

Docking Studies ◽

Potent Inhibition ◽

Brain Barrier Permeability ◽

Electric Eel ◽

Ic50 Values ◽

Ellman’S Method

Background: Hydrazide-hydrazones have been known as scaffold with various biological activities including inhibition of acetyl- (AChE) and butyrylcholinesterase (BuChE). Cholinesterase inhibitors are mainstays of dementias’ treatment. Objective: Twenty-five iodinated hydrazide-hydrazones and their analogues were designed as potential central AChE and BuChE inhibitors. Methods: Hydrazide-hydrazones were synthesized from 4-substituted benzohydrazides and 2-/4- hydroxy-3,5-diiodobenzaldehydes. The compounds were investigated in vitro for their potency to inhibit AChE from electric eel and BuChE from equine serum using Ellman’s method. We calculated also physicochemical and structural parameters for CNS delivery. Results: The derivatives exhibited a moderate dual inhibition with IC50 values ranging from 15.1-140.5 and 35.5 to 170.5 μmol.L-1 for AChE and BuChE, respectively. Generally, the compounds produced a balanced or more potent inhibition of AChE. N'-[(E)-(4-Hydroxy-3,5-diiodophenyl)methylidene]-4- nitrobenzohydrazide 2k and 4-fluoro-N'-(2-hydroxy-3,5-diiodobenzyl)benzohydrazide 3a were the most potent inhibitors of AChE and BuChE, respectively. Structure-activity relationships were established, and molecular docking studies confirmed interaction with enzymes. Conclusion: Many novel hydrazide-hydrazones showed lower IC50 values than rivastigmine against AChE and some of them were comparable for BuChE to this drug used for the treatment of dementia. They interact with cholinesterases via non-covalent binding into the active site. Based on the BOILEDEgg approach, the majority of the derivatives met the criteria for blood-brain-barrier permeability.

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Magnetic-field-induced self-assembly of FeCo/CoFe2O4 core/shell nanoparticles with tunable collective magnetic properties

Nanoscale ◽

10.1039/d1nr00136a ◽

2021 ◽

Vol 13 (8) ◽

pp. 4519-4529

Author(s):

J. Mohapatra ◽

J. Elkins ◽

M. Xing ◽

D. Guragain ◽

Sanjay R. Mishra ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Properties ◽

Physical Properties ◽

Self Assembly ◽

Core Shell ◽

Shell Nanoparticles ◽

Novel Approach ◽

Core Shell Nanoparticles

Self-assembly of nanoparticles into ordered patterns is a novel approach to build up new consolidated materials with desired collective physical properties.

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Controlling the Kinetics of an Enzymatic Reaction through Enzyme or Substrate Confinement into Lipid Mesophases with Tunable Structural Parameters

International Journal of Molecular Sciences ◽

10.3390/ijms21145116 ◽

2020 ◽

Vol 21 (14) ◽

pp. 5116

Author(s):

Marco Mendozza ◽

Arianna Balestri ◽

Costanza Montis ◽

Debora Berti

Keyword(s):

Reaction Kinetics ◽

Self Assembly ◽

Liquid Crystalline ◽

Structural Parameters ◽

Enzymatic Reaction ◽

X Ray Scattering ◽

Nitrophenyl Phosphate ◽

Vis Spectroscopy ◽

Kinetics Of ◽

Enzyme Alkaline Phosphatase

Lipid liquid crystalline mesophases, resulting from the self-assembly of polymorphic lipids in water, have been widely explored as biocompatible drug delivery systems. In this respect, non-lamellar structures are particularly attractive: they are characterized by complex 3D architectures, with the coexistence of hydrophobic and hydrophilic regions that can conveniently host drugs of different polarities. The fine tunability of the structural parameters is nontrivial, but of paramount relevance, in order to control the diffusive properties of encapsulated active principles and, ultimately, their pharmacokinetics and release. In this work, we investigate the reaction kinetics of p-nitrophenyl phosphate conversion into p-nitrophenol, catalysed by the enzyme Alkaline Phosphatase, upon alternative confinement of the substrate and of the enzyme into liquid crystalline mesophases of phytantriol/H2O containing variable amounts of an additive, sucrose stearate, able to swell the mesophase. A structural investigation through Small-Angle X-ray Scattering, revealed the possibility to finely control the structure/size of the mesophases with the amount of the included additive. A UV–vis spectroscopy study highlighted that the enzymatic reaction kinetics could be controlled by tuning the structural parameters of the mesophase, opening new perspectives for the exploitation of non-lamellar mesophases for confinement and controlled release of therapeutics.

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Self-assembly control of water-solubilised single-walled carbon nanotubes by combination of reduction and ligand exchange reactions of transition metal complexes

Supramolecular Chemistry ◽

10.1080/10610278.2010.514905 ◽

2011 ◽

Vol 23 (1-2) ◽

pp. 102-105 ◽

Cited By ~ 1

Author(s):

Kazuyuki Nobusawa ◽

Atsushi Ikeda ◽

Jun-ichi Kikuchi

Keyword(s):

Carbon Nanotubes ◽

Transition Metal ◽

Metal Complexes ◽

Transition Metal Complexes ◽

Self Assembly ◽

Ligand Exchange ◽

Single Walled Carbon Nanotubes ◽

Exchange Reactions ◽

Single Walled Carbon ◽

Walled Carbon Nanotubes

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A structural approach to control of transitional waves of nonlinear diffusion-reaction systems: Theory and possible applications to bio-medicine

Discrete Dynamics in Nature and Society ◽

10.1080/10260220290013499 ◽

2002 ◽

Vol 7 (1) ◽

pp. 27-40 ◽

Cited By ~ 1

Author(s):

Victor Kardashov ◽

Shmuel Einav

Keyword(s):

Nonlinear Diffusion ◽

Structural Parameters ◽

Deterministic Chaos ◽

Reaction Diffusion ◽

Diffusion Reaction ◽

Reaction Diffusion Systems ◽

Diffusion Systems ◽

Novel Approach ◽

Dynamics Models ◽

And Control

This paper has considered a novel approach to structural recognition and control of nonlinear reaction-diffusion systems (systems with density dependent diffusion). The main consistence of the approach is interactive variation of the nonlinear diffusion and sources structural parameters that allows to implement a qualitative control and recognition of transitional system conditions (transients). The method of inverse solutions construction allows formulating the new analytic conditions of compactness and periodicity of the transients that is also available for nonintegrated systems. On the other hand, using of energy conservations laws, allows transfer to nonlinear dynamics models that gives the possiblity to apply the modern deterministic chaos theory (particularly the Feigenboum's universal constants and scenario of chaotic transitions).

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Metabolic and immune markers for precise monitoring of COVID-19 severity and treatment

10.1101/2021.09.05.21263141 ◽

2021 ◽

Author(s):

André F. Rendeiro ◽

Charles Kyriakos Vorkas ◽

Jan Krumsiek ◽

Harjot Singh ◽

Shashi Kapatia ◽

...

Keyword(s):

Temporal Dynamics ◽

Severe Disease ◽

Deep Understanding ◽

Response To Therapy ◽

High Dimensional ◽

Time Resolved ◽

Novel Approach ◽

Metabolomic Data ◽

Clinical Action ◽

Rich Information

AbstractDeep understanding of the SARS-CoV-2 effects on host molecular pathways is paramount for the discovery of early biomarkers of outcome of coronavirus disease 2019 (COVID-19) and the identification of novel therapeutic targets. In that light, we generated metabolomic data from COVID-19 patient blood using high-throughput targeted nuclear magnetic resonance (NMR) spectroscopy and high-dimensional flow cytometry. We find considerable changes in serum metabolome composition of COVID-19 patients associated with disease severity, and response to tocilizumab treatment. We built a clinically annotated, biologically-interpretable space for precise time-resolved disease monitoring and characterize the temporal dynamics of metabolomic change along the clinical course of COVID-19 patients and in response to therapy. Finally, we leverage joint immuno-metabolic measurements to provide a novel approach for patient stratification and early prediction of severe disease. Our results show that high-dimensional metabolomic and joint immune-metabolic readouts provide rich information content for elucidation of the host’s response to infection and empower discovery of novel metabolic-driven therapies, as well as precise and efficient clinical action.

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Nitrogen-Doped Porous Co3O4/Graphene Nanocomposite for Advanced Lithium-Ion Batteries

Nanomaterials ◽

10.3390/nano9091253 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1253 ◽

Cited By ~ 5

Author(s):

Huihui Zeng ◽

Baolin Xing ◽

Lunjian Chen ◽

Guiyun Yi ◽

Guangxu Huang ◽

...

Keyword(s):

Lithium Ion Batteries ◽

Anode Material ◽

Self Assembly ◽

Active Sites ◽

Large Scale ◽

Lithium Ion ◽

Reversible Capacity ◽

Co3o4 Nanoparticles ◽

Nitrogen Doped ◽

Novel Approach

A novel approach is developed to synthesize a nitrogen-doped porous Co3O4/anthracite-derived graphene (Co3O4/AG) nanocomposite through a combined self-assembly and heat treatment process using resource-rich anthracite as a carbonaceous precursor. The nanocomposite contains uniformly distributed Co3O4 nanoparticles with a size smaller than 8 nm on the surface of porous graphene, and exhibits a specific surface area (120 m2·g−1), well-developed mesopores distributed at 3~10 nm, and a high level of nitrogen doping (5.4 at. %). These unique microstructure features of the nanocomposite can offer extra active sites and efficient pathways during the electrochemical reaction, which are conducive to improvement of the electrochemical performance for the anode material. The Co3O4/AG electrode possesses a high reversible capacity of 845 mAh·g−1 and an excellent rate capacity of 587 mAh·g−1. Furthermore, a good cyclic stability of 510 mAh·g−1 after 100 cycles at 500 mA·g−1 is maintained. Therefore, this work could provide an economical and effective route for the large-scale application of a Co3O4/AG nanocomposite as an excellent anode material in lithium-ion batteries.

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Optically Controlled Optical Modulator using a Self-Assembled 2D Plasmonic Crystal

MRS Proceedings ◽

10.1557/proc-1248-d11-22 ◽

2010 ◽

Vol 1248 ◽

Author(s):

Yi Lou ◽

John F. Muth

Keyword(s):

Self Assembly ◽

Red Light ◽

Hexagonal Lattice ◽

Resonance Wavelength ◽

Dielectric Constants ◽

Optical Modulator ◽

Optical Polymer ◽

Plasmonic Crystal ◽

Novel Approach ◽

Assembly Technique

AbstractThe surface plasmon enhanced transmission of light though a plasmonic crystal provides a novel approach for fabricating an optical modulator. The extraordinary transmission passing though these patterned metallic films is very sensitive to the surface dielectric environment. In this study, hexagonal lattice plasmonic crystals were fabricated with a self-assembly technique. Arrays of gold nano-holes or bumps with 500/600 nm periodicity were used to test the sensitivity of plasmon resonance wavelength for liquids and polymers with different dielectric constants. A nonlinear optical polymer P3HT coated onto the plasmonic crystal and pumped with 475 nm laser was found to modulate the transmission of a normally incident red light at 670 nm.

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