scholarly journals Conformational properties of biocompatible poly(2-ethyl-2-oxazoline)s in phosphate buffered saline

2018 ◽  
Vol 9 (17) ◽  
pp. 2232-2237 ◽  
Author(s):  
Alexander S. Gubarev ◽  
Bryn D. Monnery ◽  
Alexey A. Lezov ◽  
Ondrej Sedlacek ◽  
Nikolai V. Tsvetkov ◽  
...  
Keyword(s):  
Segment Length ◽  
Kuhn Segment ◽  
Physiological Conditions ◽  
Conformational Properties ◽  
Phosphate Buffered Saline ◽  
Kuhn Segment Length

The Kuhn segment length of PEtOx as a flexible macromolecule under physiological conditions is undoubtedly decreasing when approaching the LCST.

MODELLING OF POLYCOMB-DEPENDENT CHROMOSOMAL INTERACTIONS INVOLVED IN DROSOPHILA GENE SILENCING

2006 ◽  
Vol 17 (05) ◽  
pp. 757-767
Author(s):  
SILKE RITTER ◽  
JENS ODENHEIMER ◽  
DIETER W. HEERMANN ◽  
FREDERIC BANTIGNIES ◽  
CHARLOTTE GRIMAUD ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Drosophila Melanogaster ◽  
Gene Silencing ◽  
Polymer Chains ◽  
Segment Length ◽  
Kuhn Segment ◽  
End Points ◽  
Wall Distance ◽  
Repulsive Forces ◽  
Kuhn Segment Length

The conditions of the chromosomes inside the nucleus in the Rabl configuration have been modelled as self-avoiding polymer chains under restraining conditions. To ensure that the chromosomes remain stretched out and lined up, we fixed their end points to two opposing walls. The numbers of segments N, the distances d1 and d2 between the fixpoints, and the wall-to-wall distance z (as measured in segment lengths) determine an approximate value for the Kuhn segment length kl. We have simulated the movement of the chromosomes using molecular dynamics to obtain the expected distance distribution between the genetic loci in the absence of further attractive or repulsive forces. A comparison to biological experiments on Drosophila Melanogaster yields information on the parameters for our model. With the correct parameters it is possible to draw conclusions on the strength and range of the attraction that leads to pairing.

MODELLING OF POLYCOMB-DEPENDENT CHROMOSOMAL INTERACTIONS INVOLVED IN DROSOPHILA GENE SILENCING

2006 ◽  
Vol 01 (02) ◽  
pp. 141-151
Author(s):  
SILKE RITTER ◽  
JENS ODENHEIMER ◽  
DIETER W. HEERMANN ◽  
FREDERIC BANTIGNIES ◽  
CHARLOTTE GRIMAUD ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Drosophila Melanogaster ◽  
Gene Silencing ◽  
Polymer Chains ◽  
Segment Length ◽  
Kuhn Segment ◽  
End Points ◽  
Wall Distance ◽  
Repulsive Forces ◽  
Kuhn Segment Length

The conditions of the chromosomes inside the nucleus in the Rabl configuration have been modelled as self-avoiding polymer chains under restraining conditions. To ensure that the chromosomes remain stretched out and lined up, we fixed their end points to two opposing walls. The numbers of segments N, the distances d1 and d2 between the fixpoints, and the wall-to-wall distance z (as measured in segment lengths) determine an approximate value for the Kuhn segment length kl. We have simulated the movement of the chromosomes using molecular dynamics to obtain the expected distance distribution between the genetic loci in the absence of further attractive or repulsive forces. A comparison to biological experiments on Drosophila Melanogaster yields information on the parameters for our model. With the correct parameters it is possible to draw conclusions on the strength and range of the attraction that leads to pairing.

scholarly journals Synthesis and Spectral Properties of 6'-Triazolyl-Dihydroxanthene-Hemicyanine Fused Near-Infrared Dyes

2020 ◽  
Author(s):  
Gu Lingyue ◽  
Kévin RENAULT ◽  
Anthony ROMIEU ◽  
Jean-Alexandre RICHARD ◽  
Rajavel Srinivasan
Keyword(s):  
Optical Properties ◽  
Spectral Properties ◽  
Molecular Diversity ◽  
Near Infrared ◽  
Click Reaction ◽  
Fine Tuning ◽  
Active Materials ◽  
Hybrid Scaffold ◽  
Physiological Conditions ◽  
Phosphate Buffered Saline

We describe the synthesis of a range of 6’-triazolyl-dihydroxanthene-hemicyanine (DHX-hemicyanine) fused dyes through an effective copper-catalyzed azide-alkyne cycloaddition (CuAAC) "click" reaction, with the dual aim of providing molecular diversity and fine tuning spectral properties of these near-infrared (NIR)-active materials. This was implemented by reacting 16 different aliphatic and aromatic azides with a terminal alkynyl-based-DHX-hemicyanine hybrid scaffold prepared in four steps and 35% overall yield from 4-bromosalicylaldehyde. The resulting triazole derivatives have been fully characterized and their optical properties determined both in organic solvents and simulated physiological conditions (phosphate buffered saline containing 5% of bovine serum albumin protein). This systematic study is a first important step towards the development of NIR-I fluorogenic "click-on" dyes or related photoactive agents for light-based diagnostic and/or therapeutic applications.

scholarly journals Degradation of ZIF-8 in phosphate buffered saline media

CrystEngComm ◽  
2019 ◽  
Vol 21 (31) ◽  
pp. 4538-4544 ◽  
Author(s):  
Miriam de J. Velásquez-Hernández ◽  
Raffaele Ricco ◽  
Francesco Carraro ◽  
F. Ted Limpoco ◽  
Mercedes Linares-Moreau ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Zeolitic Imidazolate Framework ◽  
Physiological Conditions ◽  
The Stability ◽  
Phosphate Buffered Saline

Understanding the stability of zeolitic imidazolate framework-8 (ZIF-8) under physiological conditions is critical in biotechnology and biomedicine for biosensing, biocatalysis, and drug delivery.

scholarly journals The Structure of Dipolar Polymer Brushes and Their Interaction in the Melt. Impact of Chain Stiffness

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2887
Author(s):  
Ivan V. Mikhailov ◽  
Victor M. Amoskov ◽  
Anatoly A. Darinskii ◽  
Tatiana M. Birshtein
Keyword(s):  
Polymer Brushes ◽  
Dipole Moments ◽  
Segment Length ◽  
Chain Rigidity ◽  
Chain Stiffness ◽  
Dipole Interactions ◽  
Consistent Field ◽  
Self Consistent Field ◽  
Two Populations ◽  
Kuhn Segment Length

By using the numerical lattice Scheutjens–Fleer self-consistent field (SF-SCF) method we have studied the effect of the restricted flexibility of grafted chains on the structure and mutual interaction of two opposing planar conventional and A-type dipolar brushes. Brushes are immersed in the solvent consisting of chains similar to the grafted ones. The increase of the chain rigidity enhances the segregation of grafted chains in a A-type dipolar brush into two populations: backfolded chains with terminal monomers near the grafting surface and chains with the ends at the brush periphery. The fraction of backfolded chains grows by an increase of the Kuhn segment length. It is shown that two opposite A-type dipolar brushes from semi-rigid chains are attracted to each other at short distances. The attraction becomes more pronounced and begins at larger distances for more rigid chains with the same brush characteristics: polymerization degree, grafting density, and dipole moments of monomer units. This attraction is connected with the dipole-dipole interactions between chains of oncoming brushes with oppositely directed dipoles penetrating deeply into each other upon contact. This effect of the chain rigidity is opposite to that for conventional brushes without dipoles in the chains. For such brushes, an increase in the chain rigidity leads to the enhanced repulsion between them.

scholarly journals Synthesis and Spectral Properties of 6'-Triazolyl-Dihydroxanthene-Hemicyanine Fused Near-Infrared Dyes

2020 ◽  
Author(s):  
Gu Lingyue ◽  
Kévin RENAULT ◽  
Anthony ROMIEU ◽  
Jean-Alexandre RICHARD ◽  
Rajavel Srinivasan
Keyword(s):  
Optical Properties ◽  
Spectral Properties ◽  
Molecular Diversity ◽  
Near Infrared ◽  
Click Reaction ◽  
Fine Tuning ◽  
Active Materials ◽  
Hybrid Scaffold ◽  
Physiological Conditions ◽  
Phosphate Buffered Saline

We describe the synthesis of a range of 6’-triazolyl-dihydroxanthene-hemicyanine (DHX-hemicyanine) fused dyes through an effective copper-catalyzed azide-alkyne cycloaddition (CuAAC) "click" reaction, with the dual aim of providing molecular diversity and fine tuning spectral properties of these near-infrared (NIR)-active materials. This was implemented by reacting 16 different aliphatic and aromatic azides with a terminal alkynyl-based-DHX-hemicyanine hybrid scaffold prepared in four steps and 35% overall yield from 4-bromosalicylaldehyde. The resulting triazole derivatives have been fully characterized and their optical properties determined both in organic solvents and simulated physiological conditions (phosphate buffered saline containing 5% of bovine serum albumin protein). This systematic study is a first important step towards the development of NIR-I fluorogenic "click-on" dyes or related photoactive agents for light-based diagnostic and/or therapeutic applications.

scholarly journals Methylated Trivalent Arsenic-Glutathione Complexes are More Stable than their Arsenite Analog

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Andrew J. Percy ◽  
Jürgen Gailer
Keyword(s):  
Arsenic Species ◽  
Size Exclusion ◽  
Trivalent Arsenic ◽  
Physiological Conditions ◽  
Column Formation ◽  
Monomethylarsonous Acid ◽  
Exclusion Chromatography ◽  
Dimethylarsinous Acid ◽  
Phosphate Buffered Saline ◽  
Comparative Stability

The trivalent arsenic glutathione complexes arsenic triglutathione, methylarsonous diglutathione, and dimethylarsinous glutathione are key intermediates in the mammalian metabolism of arsenite and possibly represent the arsenic species that are transported from the liver to the kidney for urinary excretion. Despite this, the comparative stability of the arsenic-sulfur bonds in these complexes has not been investigated under physiological conditions resembling hepatocyte cytosol. Using size-exclusion chromatography and a glutathione-containing phosphate buffered saline mobile phase (5 or 10 mM glutathione, pH 7.4) in conjunction with an arsenic-specific detector, we chromatographed arsenite, monomethylarsonous acid, and dimethylarsinous acid. The on-column formation of the corresponding arsenic-glutathione complexes between 4 and37°C revealed that methylated arsenic-glutathione complexes are more stable than arsenic triglutathione. The relevance of these results with regard to the metabolic fate of arsenite in mammals is discussed.

scholarly journals Fabrication of a Robust In2O3 Nanolines FET Device as a Biosensor Platform

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 642
Author(s):  
Zetao Zhu ◽  
Takao Yasui ◽  
Quanli Liu ◽  
Kazuki Nagashima ◽  
Tsunaki Takahashi ◽  
...  
Keyword(s):  
Field Effect Transistors ◽  
Physiological Solution ◽  
Semiconductor Materials ◽  
Surface Immobilization ◽  
Electrical Stability ◽  
Physiological Conditions ◽  
Debye Shielding ◽  
Conductive Channel ◽  
Phosphate Buffered Saline

Field-effect transistors (FETs) are attractive biosensor platforms for rapid and accurate detection of various analytes through surface immobilization of specific bio-receptors. Since it is difficult to maintain the electrical stability of semiconductors of sensing channel under physiological conditions for long periods, passivation by a stable metal oxide dielectric layer, such as Al2O3 or HfO2, is currently used as a common method to prevent damage. However, protecting the sensing channel by passivation has the disadvantage that the distance between the target and the conductive channel increases, and the sensing signal will be degraded by Debye shielding. Even though many efforts use semiconductor materials directly as channels for biosensors, the electrical stability of semiconductors in the physiological environments has rarely been studied. In this work, an In2O3 nanolines FET device with high robustness in artificial physiological solution of phosphate buffered saline (PBS) was fabricated and used as a platform for biosensors without employing passivation on the sensing channel. The FET device demonstrated reproducibility with an average threshold voltage (VTH) of 5.235 V and a standard deviation (SD) of 0.382 V. We tested the robustness of the In2O3 nanolines FET device in PBS solution and found that the device had a long-term electrical stability in PBS with more than 9 days’ exposure. Finally, we demonstrated its applicability as a biosensor platform by testing the biosensing performance towards miR-21 targets after immobilizing the phosphonic acid terminated DNA probes. Since the surface immobilization of multiple bioreceptors is feasible, we demonstrate that the robust In2O3 FET device can be an excellent biosensor platform for biosensors.

Ultrastructure of Giant Mitochondria and Their Inclusions in Schwann Cells of Bovine Splenic Nerve

1974 ◽  
Vol 32 ◽  
pp. 194-195
Author(s):  
Å. Thureson-Klein
Keyword(s):  
Schwann Cells ◽  
Cell Organelles ◽  
Giant Mitochondria ◽  
Matrix Density ◽  
Physiological Conditions ◽  
Unmyelinated Axons ◽  
Internal Structures ◽  
Structural Abnormalities ◽  
Cytotoxic Compounds ◽  
Cell Components

Giant mitochondria of various shapes and with different internal structures and matrix density have been observed in a great number of tissues including nerves. In most instances, the presence of giant mitochondria has been associated with a known disease or with abnormal physiological conditions such as anoxia or exposure to cytotoxic compounds. In these cases degenerative changes occurred in other cell organelles and, therefore the giant mitochondria also were believed to be induced structural abnormalities.Schwann cells ensheating unmyelinated axons of bovine splenic nerve regularly contain giant mitochondria in addition to the conventional smaller type (Fig. 1). These nerves come from healthy inspected animals presumed not to have been exposed to noxious agents. As there are no drastic changes in the small mitochondria and because other cell components also appear reasonably well preserved, it is believed that the giant mitochondria are normally present jin vivo and have not formed as a post-mortem artifact.

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