Zn(ii)-Dipicolylamine analogues with amphiphilic side chains endow low molecular weight PEI with high transfection performance

2021 ◽  
Vol 9 (8) ◽  
pp. 3090-3099
Author(s):  
Zhaoming Chen ◽  
Xindong Wang ◽  
Shuai Liu ◽  
Yumeng Li ◽  
Hao Zhou ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Side Chains ◽  
Functional Modules

We fabricated a series of Zn(ii)-dipicolylamine functional modules with different hydrophilic-phobic side chains to modify low molecular weight PEI in order to investigate the effect of amphiphilic balance of them on the transfection process.

The Velocity of Propagation of Ultrasonic Waves and the Form of the Molecules of High Polymers

1950 ◽  
Vol 23 (1) ◽  
pp. 151-162
Author(s):  
Giulio Natta ◽  
Mario Baccaredda
Keyword(s):  
Molecular Weight ◽  
Form Factor ◽  
Experimental Error ◽  
Ultrasonic Waves ◽  
Low Molecular Weight ◽  
Side Chains ◽  
Polyethylene Oxides ◽  
Velocity Of Propagation ◽  
Secondary Side ◽  
Linear Macromolecules

Abstract The velocity of propagation of ultrasonic waves in numerous substances of high molecular weight was determined. For substances not fusible at temperatures below 100° C, this velocity was determined by extrapolation from solutions considered ideal. For linear macromolecules without side chains, the ultrasonic velocity appears to be practically equal, within the limits of experimental error, to that calculated by the formula of Rao and on a basis of the additive values of the bond velocity of Lagemann and Corry. For molecules which have many side chains, the velocity is lower than the calculated value, whereas for compounds of low molecular weight this deviation is relatively small, viz., less than 10 per cent; it becomes much higher, viz., almost up to 40 per cent, for macromolecules. The form factor is defined as the ratio of the velocity determined experimentally to the velocity calculated by the formula of Rao. This form factor is equal to 1 for polymers without side chains or with very few side chains, such as paraffins, polyethylenes, Nylon, polyethylene oxides, and polyoxymethylenes; is only 0.89–0.90 for natural rubber; only 0.82–0.84 for Buna and for hydrogenated Buna, poly-α-butylenes, and polystyrenes; only 0.79–0.80 for polyisobutylenes; only 0.89 for polymethacrylates; only 0.78 for polyvinylisobutyl ethers; only 0.65 for Butyl rubber; and only 0.63 for polymethyl methacrylates. The form factor is thus affected by the frequency and length of the side chains, and by any secondary side chains which may be present.

Thermal and Liquid Crystalline Properties of a Polymer with Amphiphilic-Mesogenic Side-Chains

2001 ◽  
Vol 709 ◽  
Author(s):  
Seiji Ujiie ◽  
Yumi Yano ◽  
Akira Mori
Keyword(s):  
Molecular Weight ◽  
Liquid Crystalline ◽  
Water Soluble ◽  
Low Molecular Weight ◽  
Side Chains ◽  
Columnar Phase ◽  
Smectic A ◽  
Smectic C ◽  
Heating And Cooling ◽  
Lyotropic Mesophases

ABSTRACTA low-molecular-weight liquid crystalline amphiphilic compound (Az6Bu) and a liquid crystalline polymethacrylate [P(Az6Bu)] with amphiphilic-mesogenic side-chains are reported in this present paper. A polyethyleneimine chain with 2-hydroxyethyl side-groups was used as the water-soluble spacer. Az6Bu exhibited a lyotropic columnar phase and no thermotropic mesophase. P(Az6Bu) showed thermotropic and lyotropic liquid crystalline properties. P(Az6Bu) formed thermotropic smectic A and C mesophases on the heating and cooling processes. The lyotropic systems consisting of P(Az6Bu) and water exhibited a smectic C lyomesophase with oilystreak and schlieren textures. The layered structures formed in the thermotropic and lyotropic mesophases are composed of a sublayer produced by the anisotropic alignment of aromatic-mesogenic groups and a sublayer of hydrophilic groups.

Synthesis and evaluation of chiral β-amino acid-based low-molecular-weight organogelators possessing a methyl/trifluoromethyl side chain

2019 ◽  
Vol 43 (7) ◽  
pp. 2882-2887 ◽  
Author(s):  
Koichi Kodama ◽  
Ryuta Kawamata ◽  
Takuji Hirose
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Supramolecular Structures ◽  
Side Chain ◽  
Low Molecular Weight ◽  
Side Chains ◽  
Low Molecular Weight Organogelators

Impacts of side-chains and chirality of organogelators derived from β-amino acids are described with their supramolecular structures.

Factors Controlling Ionic Conductivity of Plasticized and Non-Plasticized Crosslinked Polyether Electrolytes

1990 ◽  
Vol 210 ◽  
Author(s):  
Douglas R. MacFarlane ◽  
Jeffrey M. Hey ◽  
Maria Forsyth
Keyword(s):  
Molecular Weight ◽  
Crosslink Density ◽  
Room Temperature ◽  
Marked Effect ◽  
Major Effect ◽  
Low Molecular Weight ◽  
Side Chains ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Elastomeric Materials

AbstractA series of elastomeric (urethane crosslinked) polyether electrolytes have been prepared in order to investigate the influence on conductivity of crosslink density, length of uninterrupted polyether chain, number of side chains and plasticizer content. Crosslink density was found to only weakly influence conductivity, but had the expected major effect on elastic modulus. Increases in uninterrupted polyether chain length were also found to enhance conductivity. The number of side chains (acting as an internal plasticizer) was not found to have a marked effect on conductivity within the range studied. The highest room temperature conductivity observed in these non-plasticized elastomers was 3 × 10-5 Ω-1 cm-1. Addition of a low molecular weight plasticizer such as tetraglyme was found to markedly increase the conductivity and lower Tg. The highest room temperature conductivity observed in 50% plasticized elastomeric materials was 10-3 Ω-1cm-1.

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Low-molecular-weight heparin in the prevention and treatment of thromboembolic disorders

1998 ◽  
Vol 1 (5) ◽  
pp. 166-174 ◽  
Author(s):  
Evelyn R Hermes De Santis ◽  
Betsy S Laumeister ◽  
Vidhu Bansal ◽  
Vandana Kataria ◽  
Preeti Loomba ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Low Molecular Weight ◽  
Prevention And Treatment
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