Macroporous polymer beads derived from a novel coporogen of polyethylene/dichlorobenzene

AbstractMacroporous poly(divinylbenzene) (PDVB) beads were prepared by traditional suspension polymerization in the presence of dichlorobenzene (DCB) and polyethylene (PE) as coporogen. Two types of PE with different molecular weights were used as polymer porogen, and the weight percent of PE in DCB varied from 0 to 8.0 wt%. Effects of PE concentration and PE molecular weight on the pore structure of PDVB beads were investigated. As expected, the highest surface area was achieved by the beads prepared with DCB as the sole porogen. Applying coporogen with PE with low molecular weight (LPE) content, the surface area of PDVB beads declined because of early phase separation induced by the cooperation of LPE and DCB. However, the value increased abruptly when 5 wt% LPE in DCB was used as coporogen. Subsequently, the values again decreased when LPE amount further increased. Overall, the molecular weight of PE and the concentration of PE in coporogen had a significant effect on the pore structure and surface morphology of PDVB beads.

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Anticoagulant Properties of a Green Algal Rhamnan-type Sulfated Polysaccharide and Its Low-molecular-weight Fragments Prepared by Mild Acid Degradation

Marine Drugs ◽

10.3390/md16110445 ◽

2018 ◽

Vol 16 (11) ◽

pp. 445 ◽

Cited By ~ 7

Author(s):

Xue Liu ◽

Peng Du ◽

Xiao Liu ◽

Sujian Cao ◽

Ling Qin ◽

...

Keyword(s):

Molecular Weight ◽

Anticoagulant Activity ◽

Sulfated Polysaccharide ◽

Low Molecular Weight ◽

Thrombin Time ◽

Acid Degradation ◽

Molecular Weights ◽

Green Algal

The active sulfated polysaccharide from seaweed possesses important pharmaceutical and biomedical potential. In the study, Monostroma sulfated polysaccharide (MSP) was obtained from Monostroma angicava, and the low-molecular-weight fragments of MSP (MSP-Fs: MSP-F1–MSP-F6) were prepared by controlled acid degradation. The molecular weights of MSP and MSP-F1–MSP-F6 were 335 kDa, 240 kDa, 90 kDa, 40 kDa, 24 kDa, 12 kDa, and 6.8 kDa, respectively. The polysaccharides were sulfated rhamnans that consisted of →3)-α-l-Rhap-(1→ and →2)-α-l-Rhap-(1→ units with partial sulfation at C-2 of →3)-α-l-Rhap-(1→ and C-3 of →2)-α-l-Rhap-(1→. Anticoagulant properties in vitro of MSP and MSP-F1–MSP-F6 were evaluated by studying the activated partial thromboplastin time, thrombin time, and prothrombin time. Anticoagulant activities in vivo of MSP and MSP-F4 were further evaluated; their fibrin(ogen)olytic activities in vivo and thrombolytic properties in vitro were also assessed by D-dimer, fibrin degradation products, plasminogen activator inhibitior-1, and clot lytic rate assays. The results showed that MSP and MSP-F1–MSP-F4 with molecular weights of 24–240 kDa had strong anticoagulant activities. A decrease in the molecular weight of MSP-Fs was accompanied by a decrease in the anticoagulant activity, and higher anticoagulant activity requires a molecular weight of over 12 kDa. MSP and MSP-F4 possessed strong anticoagulant activities in vivo, as well as high fibrin(ogen)olytic and thrombolytic activities. MSP and MSP-F4 have potential as drug or helpful food supplements for human health.

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Water vapor induced self-assembly of islands/honeycomb structure by secondary phase separation in polystyrene solution with bimodal molecular weight distribution

10.26434/chemrxiv.14054033.v7 ◽

2021 ◽

Author(s):

Maciej Łojkowski ◽

Adrian Chlanda ◽

Emilia Choińska ◽

Wojciech Swieszkowski

Keyword(s):

Molecular Weight ◽

Phase Separation ◽

Molecular Weight Distribution ◽

Weight Distribution ◽

Self Assembly ◽

Secondary Phase ◽

Honeycomb Structure ◽

Polymer Chains ◽

Molecular Weights ◽

Secondary Phase Separation

<p>The formation of complex structures in thin films is of interest in many fields. Segregation of polymer chains of different molecular weights is a well-known process. However, here, polystyrene with bimodal molecular weight distribution, but no additional chemical modification was used. It was proven that at certain conditions, the phase separation occurred between two fractions of bimodal polystyrene/methyl ethyl ketone solution. The films were prepared by spin-coating, and the segregation between polystyrene phases was investigated by force spectroscopy. Next, water vapour induced secondary phase separation was investigated. The introduction of moist airflow induced the self-assembly of the lower molecular weight into islands and the heavier fraction into a honeycomb. As a result, an easy, fast, and effective method of obtaining island/honeycomb morphologies was demonstrated. The possible mechanisms of the formation of such structures were discussed.</p>

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Biodegradation of low molecular weight polyacrylamide under aerobic and anaerobic conditions: effect of the molecular weight

Water Science & Technology ◽

10.2166/wst.2020.109 ◽

2020 ◽

Vol 81 (2) ◽

pp. 301-308 ◽

Cited By ~ 1

Author(s):

Wenzhe Song ◽

Yu Zhang ◽

Amir Hossein Hamidian ◽

Min Yang

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Carbon Chain ◽

Anaerobic Treatment ◽

Low Molecular Weight ◽

Amino Groups ◽

Molecular Weights ◽

Weight One ◽

Hydrolysis Of ◽

Aerobic And Anaerobic

Abstract The biodegradation of polyacrylamide (PAM) includes the hydrolysis of amino groups and cleavage of the carbon chain; however, the effect of molecular weight on the biodegradation needs further investigations. In this study, biodegradation of low molecular weight PAM (1.6 × 106 Da) was evaluated in two aerobic (25 °C and 40 °C) and two anaerobic (35 °C and 55 °C) reactors over 100 days. The removal of the low molecular weight PAM (52.0–52.6%) through the hydrolysis of amino groups by anaerobic treatment (35 °C and 55 °C) was much higher than that of the high molecular weight (2.2 × 107 Da, 11.2–17.0%) observed under the same conditions. The molecular weight was reduced from 1.6 × 106 to 6.45–7.42 × 105 Da for the low molecular weight PAM, while the high molecular weight PAM declined from 2.2 × 107 to 3.76–5.87 × 106 Da. The results showed that the amino hydrolysis of low molecular weight PAM is easier than that of the high molecular weight one, while the cleavage of its carbon chain is still difficult. The molecular weights of PAM in the effluents from the two aerobic reactors (25 °C and 40 °C) were further reduced to 4.31 × 105 and 5.68 × 105 Da by the biofilm treatment, respectively. The results would be useful for the management of wastewater containing PAM.

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Low Molecular Weight Heparin Reduces Proteinuria and Modulates Glomerular TNF-α Production in the Early Phase of Adriamycin Nephropathy

Nephron ◽

10.1159/000045905 ◽

2001 ◽

Vol 87 (2) ◽

pp. 155-160 ◽

Cited By ~ 9

Author(s):

S. Benchetrit ◽

E. Golan ◽

E. Podjarny ◽

J. Green ◽

G. Rashid ◽

...

Keyword(s):

Molecular Weight ◽

Early Phase ◽

Low Molecular Weight Heparin ◽

Low Molecular Weight ◽

Adriamycin Nephropathy ◽

Tnf Α

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Comparison of exopolysaccharides from mucoid and nonmucoid strains of Clavibacter michiganensis subspecies sepedonicus

Canadian Journal of Microbiology ◽

10.1139/m93-041 ◽

1993 ◽

Vol 39 (3) ◽

pp. 291-296 ◽

Cited By ~ 14

Author(s):

Paul J. Henningson ◽

Neil C. Gudmestad

Keyword(s):

Molecular Weight ◽

High Performance ◽

Size Exclusion ◽

Enzyme Linked Immunosorbent Assay ◽

Low Molecular Weight ◽

Neutral Sugar ◽

Clavibacter Michiganensis ◽

Serological Reaction ◽

Molecular Weights ◽

Exclusion Chromatography

The exopolysaccharides produced by six strains of Clavibacter michiganensis ssp. sepedonicus were isolated and purified by liquid chromatography. Neutral sugar composition and molecular weights were determined for each polysaccharide fraction, using gas chromatography and high-performance size-exclusion chromatography. The serological reaction of each fraction was tested using enzyme-linked immunosorbent assay. Exopolysaccharide from nonmucoid strains contained only low molecular weight polysaccharides (1.5 × 103 to 1.1 × 104). Exopolysaccharide from mucoid and intermediate strains could be separated into low (4.0 × 103 to 1.1 × 104) molecular weight and high (5.0 × 105 to 1.6 × 106) molecular weight fractions. High molecular weight polysaccharides were composed almost exclusively of galactose, glucose, and fucose. The ratios of these sugars were highly variable among strains. Low molecular weight polysaccharides were primarily composed of galactose with significant and varying amounts of glucose, rhamnose, mannose, and ribose. All polysaccharide fractions except one, produced by a nonmucoid strain, reacted in the immunoassay test.Key words: exopolysaccharide, polysaccharide, Clavibacter, michiganensis, sepedonicus.

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Glass Transition and Ultrasonic Relaxation in Polystyrene

MRS Proceedings ◽

10.1557/proc-455-183 ◽

1996 ◽

Vol 455 ◽

Cited By ~ 5

Author(s):

A. Sahnoune ◽

L. Piché

Keyword(s):

Molecular Weight ◽

Relaxation Time ◽

Glass Transition ◽

Low Temperatures ◽

Relaxation Modulus ◽

Low Molecular Weight ◽

Relaxation Model ◽

Fragility Index ◽

Molecular Weights ◽

Ultrasonic Relaxation

ABSTRACTWe present measurements of the glass transition and the ultrasonic relaxation modulus in a series of monodisperse polystyrenes. The temperature dependence of the modulus was analyzed using Havriliak-Negami relaxation model (HN) and Vogel-Tammann-Fulcher equation (VTF) for the relaxation time. The results allowed us to determine the fragility index, m, which decreases with increasing molecular weight, Mn. Furthermore, the relaxation time was found to saturate at high molecular weights and varies as Mnp, in the low molecular weight region. The exponent is p≈2 at high temperatures and p ≈ 7 at low temperatures close to Tg.

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Effects Of Environmental Factors On The Dispersion Behavior Of Iron Oxide In Aqueous Solutions With Poly Acrylic Acid

Archives of Metallurgy and Materials ◽

10.1515/amm-2015-0271 ◽

2015 ◽

Vol 60 (2) ◽

pp. 1561-1564

Author(s):

E.-H. Lee ◽

K.-M. Kim ◽

W.-Y. Maeng ◽

D.-H. Hur

Keyword(s):

Molecular Weight ◽

Acrylic Acid ◽

High Molecular Weight ◽

Low Molecular Weight ◽

Solution Ph ◽

Molecular Weights ◽

Aqueous Suspensions ◽

Magnetite Particles ◽

The Stability ◽

Poly Acrylic Acid

Abstract After preparing aqueous suspensions from magnetite particles with a poly-acrylic acid, we investigated the effects of several experimental parameters. We characterized the stability of the suspensions using visual inspection, sedimentation, adsorption, and thermal stability of the dispersant. The dispersion stability is affected by the solution pH, the concentrations of magnetite particles, the molecular weight, the concentration of the dispersants, and the temperature. The stability of the suspensions increased as the concentration of the dispersant and the temperature increased. In terms of the molecular weights of the dispersant, the suspensions with dispersant of low-molecular weight (1800) were more stable than those of high-molecular weight (250000) at room temperature. However, at high temperature the suspensions with high-molecular weight showed stability. The adsorption efficiency of the dispersant was very low. The dispersant of high-molecular weight showed a higher thermal integrity than that of low-molecular weight. From this work, we obtained the optimum conditions for stable aqueous suspensions of magnetite particles.

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Molecular Weight Determinations Of Low Molecular Weight (LMW) Heparins By Ultracentrifugation And High Pressure Liquid Chromatography

10.1055/s-0038-1652694 ◽

1981 ◽

Author(s):

Grant Barlow ◽

N Sugisaka ◽

F J Petracek

Keyword(s):

Molecular Weight ◽

High Pressure ◽

Liquid Chromatography ◽

High Pressure Liquid Chromatography ◽

Low Molecular Weight ◽

Analytical Ultracentrifuge ◽

Molecular Weights ◽

Molecular Weight Distributions ◽

Weight Distributions ◽

Heparin Fractions

Molecular weights were independently determined on nitrous acid depolymerized LMW heparin fractions ranging from 2-15 daltons using the analytical ultracentrifuge and high pressure liquid chromatography (HPLC).Sedimentation-diffusion equilibria were obtained in the analytical ultracentrifuge using speeds ranging from 20,000 to 56,000 rpm. Near theta conditions were obtained using 0.5M NaCl as the solvent. Calculations of molecular weight distributions and, from those figures, weight average molecular weights were made using the method described by Scholte (N.Y. Acad Sci. 164, 156, 1969). The results show that weight average values as low as 2,000 daltons can be determined.Sedimentation-diffusion equilibria were obtained in the analytical ultracentrifuge using speeds ranging from 20,000 to 56,000 rpm. Near theta conditions were obtained using 0.5M NaCl as the solvent. Calculations of molecular weight distributions and, from those figures, weight average molecular weights were made using the method described by Scholte (N.Y. Acad Sci. 164, 156, 1969). The results show that weight average values as low as 2,000 daltons can be determined.The HPLC results were obtained using previously described methods (Fed Proc. 36, 89, 1977) and a new highly efficient gel column (TSK gels). Fractionated dextrans were used as reference standards.

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Induction of Proteasome Subunit Low Molecular Weight Protein (LMP)-2 Is Required to Induce Active Remodeling in Adult Rat Ventricular Cardiomyocytes

Medical Sciences ◽

10.3390/medsci8020021 ◽

2020 ◽

Vol 8 (2) ◽

pp. 21

Author(s):

Antonia Petersen ◽

Hanna Sarah Kutsche ◽

Franziska Nippert ◽

Rolf Schreckenberg ◽

Rainer Schulz ◽

...

Keyword(s):

Molecular Weight ◽

Early Phase ◽

Pressure Overload ◽

Low Molecular Weight ◽

Molecular Weight Protein ◽

Proteasome Subunit ◽

Adult Rat ◽

Ventricular Cardiomyocytes ◽

Weight Protein ◽

Low Molecular Weight Protein

Isolated adult rat ventricular cardiomyocytes (ARVC) adapt to the two-dimensional surface of culture dishes once they are isolated from the three-dimensional heart tissue. This process mimics aspects of cardiac adaptation to pressure overload and requires an initial breakdown of sarcomeric structures. The present study therefore aimed to identify key steps in this remodeling process. ARVC were cultured under serum-free or serum-supplemented conditions and their sizes and shapes were analyzed as well as apoptosis and the ability to disintegrate their sarcomeres. ARVC require serum-factors in order to adapt to cell culture conditions. More ARVC survived if they were able to breakdown their sarcomeres and mononucleated ARVC, which were smaller than binucleated ARVC, had a better chance to adapt. During the early phase of adaptation, proteasome subunit low molecular weight protein (LMP)-2 was induced. Inhibition of LMP-2 up-regulation by siRNA attenuated the process of successful adaptation. In vivo, LMP-2 was induced in the left ventricle of spontaneously hypertensive rats during the early phase of adaptation to pressure overload. In conclusion, the data suggest that breakdown of pre-existing sarcomeres is optimized by induction of LMP-2 and that it is required for cardiac remodeling processes, for example, occurring during pressure overload.

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