The effectiveness of interconversion methods based on the distributed nature of polymeric structure

2021 ◽  
Author(s):  
Stelios Katsourinis ◽  
Evagelia Kontou
Keyword(s):  
Polymeric Structure

Ultrastrong, Free-Standing and Large Nanofilms of Pyrenearamid

2019 ◽  
Author(s):  
Amalia Rapakousiou ◽  
Alejandro López-moreno ◽  
Belén Nieto-Ortega ◽  
M. Mar Bernal ◽  
Miguel A. Monclús ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Building Block ◽  
Aromatic Polyamide ◽  
Free Standing ◽  
Spatial Confinement ◽  
Polymeric Structure ◽  
Reduced Modulus ◽  
Organizational Arrangement ◽  
Polycyclic Aromatic ◽  
Nanoscale Building Block

We introduce poly(1,6-pyrene terephthalamide) polymer (PPyrTA) as an aromatic polyamide analogue of poly(p-phenylene terephthalamide) (PPTA), also known as Kevlar®. This work shows that the incorporation of polycyclic aromatic pyrene moieties improves drastically the mechanical properties of the polymeric structure, increasing elastic nanoindentation-determined modulus and hardness by factors of 1.9 and 4.3, respectively. Liquid deprotonated dispersions of PPyrTA nanofibers were used as nanoscale building block for producing large-surface, free-standing polymer macroscopic nanofilms. This 2D assembly leads to further significant improvements in reduced modulus and hardness (more than twice) compared to the starting polymer macroscale fibres, due to a better re-organizational arrangement of the PPyrTA nanofibers in the nanofilms, formed under 2D spatial confinement.

A Review on Microsponge Drug Delivery System

2020 ◽  
Vol 10 (2) ◽  
pp. 53-59
Author(s):  
Bharathi M ◽  
Mullaikodi O ◽  
Rajalingam D ◽  
Gnanasekar N ◽  
Kesavan M
Keyword(s):  
Drug Delivery ◽  
Drug Delivery System ◽  
Delivery System ◽  
Physical Stability ◽  
Current Investigation ◽  
Considerable Time ◽  
Polymeric Structure ◽  
Point Of Interest ◽  
Time Period ◽  
Time Specific

A Microsponge (MS) is an extremely interconnected, permeable, polymeric structure that involves permeable microparticles trapping and discharging through the skin for a considerable time period. Drug delivery system (DDS) offer extended discharge with less degradation, improved physical stability along with better tolerance. The main intend of any DDS is to achieve the required amount of drug in plasma to produce the desired therapeutic and non-poisonous effect over a prolonged period of time. Specific methods for preparing MS were reviewed in this current investigation, and their pharmaceutical implementations were signed. MS have major DDS point of interest. It also improves stability, increased flexibility in formulation and increased elegance. In fact, numerous studies have reported that MS supplies are not allergic, mutagenic, and poisonous. MS creativity is used in products such as sunscreen, prescription, cosmetics, and OTC skin care. This inquiry primarily focuses on the different methods used to identify, plan and exploit MS.

scholarly journals Gonococcal pili. Primary structure and receptor binding domain.

1984 ◽  
Vol 159 (5) ◽  
pp. 1351-1370 ◽  
Author(s):  
G K Schoolnik ◽  
R Fernandez ◽  
J Y Tai ◽  
J Rothbard ◽  
E C Gotschlich
Keyword(s):  
Amino Acids ◽  
Receptor Binding ◽  
Binding Domain ◽  
Structural Basis ◽  
Receptor Binding Domain ◽  
Variable Regions ◽  
Disulfide Linkage ◽  
Polymeric Structure ◽  
Antigenic Diversity ◽  
Single Polypeptide Chain

The complete amino acid sequence of pilin from gonococcal strain MS11 and the sequence of constant and variable regions from strain R10 pilin have been determined in order to elucidate the structural basis for adherence function, antigenic diversity, and polymeric structure. The MS11 pilin sequence consists of 159 amino acids in a single polypeptide chain with two cysteines in disulfide linkage and serine-bonded phosphate residues. TC-2 (31-111), a soluble monomeric pilus peptide prepared by arginine-specific digestion, bound human endocervical, but not buccal or HeLa cells and therefore is postulated to encompass the receptor binding domain. Variable regions of CNBr-3 appear to confer antigenic diversity and comprise segments in which changes in the position of charged residues occur in hydrophilic, beta-turns. Residues 2-21 and 202-221 of gonococcal pilins and lower eucaryotic actins, respectively, exhibit 50% homology. When these residues are arranged at intervals of 100 degrees of arc on "helical wheels," the identical amino acids comprise a hydrophobic face on one side of the helix. This observation, the hydrophobic character of this region and the tendency for TC-1 (residues 1-30) to aggregate in water, suggest that this stretch interacts with other subunits to stabilize polymeric structure.

Synthesis and Characterization of Tris(trimethyltin) Thiophosphate (Me3Sn)3PO3S

1993 ◽  
Vol 48 (12) ◽  
pp. 1781-1783 ◽  
Author(s):  
Abdel-Fattah Shihada
Keyword(s):  
Aqueous Medium ◽  
Raman Spectra ◽  
Mass Spectra ◽  
Ir And Raman Spectra ◽  
Synthesis And Characterization ◽  
Polymeric Structure ◽  
Ir And Raman

(Me3Sn)3PO3S has been prepared from the reaction of Me3SnCl with Na3PO3S • 12 H2O under cooling in aqueous medium. Its IR and Raman spectra are found to be consistent with a polymeric structure with tetra- and penta-coordinated tin atoms. The 31P NMR and mass spectra of (Me3Sn)3PO3S are reported and discussed.

scholarly journals Macromolecular properties and polymeric structure of canine tracheal mucins

1991 ◽  
Vol 276 (2) ◽  
pp. 525-532 ◽  
Author(s):  
V Shankar ◽  
A K Virmani ◽  
B Naziruddin ◽  
G P Sachdev
Keyword(s):  
Gel Electrophoresis ◽  
Guanidine Hydrochloride ◽  
Polyacrylamide Gel Electrophoresis ◽  
Hydrophobic Properties ◽  
Experimental Conditions ◽  
Protein Core ◽  
Polymeric Structure ◽  
Composite Gel ◽  
Self Association ◽  
Static Laser Light Scattering

Two high-Mr mucus glycoproteins (mucins), CTM-A and CTM-B, were highly purified from canine tracheal pouch secretions, and their macromolecular properties as well as polymeric structure were investigated. On SDS/composite-gel electrophoresis, a diffuse band was observed for each mucin. Polyacrylamide-gel electrophoresis using 6% gels also showed the absence of low-Mr contaminants in the mucins. Comparison of chemical and amino acid compositions revealed significant differences between the two mucins. Using a static-laser-light-scattering technique, CTM-A and CTM-B were found to have weight-average Mr values of about 11.0 x 10(6) and 1.4 x 10(6) respectively. Both mucins showed concentration-dependent aggregation in buffer containing 6 M-guanidine hydrochloride. Under similar experimental conditions, reduced-alkylated CTM-A had an Mr of 5.48 x 10(6) and showed no concentration-dependent aggregation. Hydrophobic properties of the mucins, investigated by the fluorescent probe technique using mansylphenylalanine as the probe, showed the presence of a large number of low-affinity (KD approx. 10(5) M) binding sites. These sites appeared to be located on the non-glycosylated regions of the protein core, since Pronase digestion of the mucins almost completely eliminated probe binding. Reduction of disulphide bonds of CTM-A and CTM-B did not significantly alter the probe-binding properties. Also, addition of increasing NaCl concentrations (0.03-1.0 M) to the buffer caused only a small change in the hydrophobic properties of native and reduced-alkylated mucins. CTM-A was deglycosylated, without notable in the hydrophobic properties of native and reduced-alkylated mucins. CTM-A was deglycosylated, without notable degradation, using a combination of chemical and enzymic methods. On SDS/PAGE the protein core was estimated to have an Mr of approx. 60,000. On the basis of the protein and carbohydrate contents of the major mucin CTM-A, the mucin monomer was calculated to have an Mr of approx. 140,000. The high Mr (11 x 10(6] observed by physical methods is therefore due to self-association of the mucin monomer subunits.

Polymeric Structure of Spruce Lignin

Science ◽  
1970 ◽  
Vol 170 (3954) ◽  
pp. 173-176 ◽  
Author(s):  
H. I. Bolker ◽  
H. S. Brenner
Keyword(s):  
Polymeric Structure

scholarly journals A polymeric oxovanadium(IV) pyromellitate complex

1999 ◽  
Vol 64 (9) ◽  
pp. 513-518
Author(s):  
Dusanka Vasovic ◽  
Djordje Stojakovic
Keyword(s):  
Ir Spectroscopy ◽  
Potassium Carbonate ◽  
Magnetic Measurements ◽  
Antiferromagnetic Coupling ◽  
Polymeric Complex ◽  
Pyromellitic Acid ◽  
Polymeric Structure

The reaction of oxovanadium(IV) sulphate with 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid) in the presence of potassium carbonate yields a polymeric complex, K2[VO(pyr)]-6H2O (I) [pyr = pyromellitate(4-) ion]. The PM3(tm) calculations and IR spectroscopy suggest that the polymeric structure of I consists of ?V-pyr-V-pyr- chains formed by the 1,4- or 1,5-bridging by the pyr ions. The chains are additionally cross-linked by the chelate function of one of the COO. groups of the pyr ion. Magnetic measurements do not reveal the presence of antiferromagnetic coupling between the V centers.

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