The Molecular Weight of Hyaluronan in Parotid and Mixed Human Saliva

Anthony Pogrel, M.,Low, Mari Anne,Stern, Robert,Schmidt, Brian L. Korean Academy of Oral Biology and the UCLA Dental 2000 International Journal of Oral Biology Vol.25 No.1

To determine the molecular weight of Hyaluronan〔hyaluronic acid〕i stimulated and unstimulated pure parotid saliva and in mixed whole saliva from the floor of the mouth. Ten volunteers where utilized for this study. Pure stimulated and unstimulated parotid saliva was obtained by cannulation of the parotid duct and mixed saliva was obtained from the floor of the mouth by aspiration. Molecular weight determination was carried out by separation on a Superose 6 column. The molecular weight of the hyaluronan in pure parotid saliva was of prdominantly high molecular weight〔>200,000Kd〕. The hyaluronan present in the mucosal saliva of the floor of the mouth had a molecular weight predominantly in the range of 20,000 to 200,000 Kd, with only 3 percent above 200,000 Kd. The precise role of hyaluronan in saliva is unknown. It may aid in the lubricating properties of saliva, it may aid in intraoral wound healing, and may act as a carrier for growth factors which are present in saliva and may hav important physiological functions. It is assumed that the lower molecular weight found in mixed saliva as against pure saliva is due to cleavage and breakdown of the hyaluronan due to bacterial action in the mouth. This bacterial action may affect the ability of the hyaluronan to transport growth factors in the oral cavity. The molecular weight of hyaluronan in mixed saliva is lower than in whole saliva. The significance of this is unknown buy may be detrimental to growth factor transport.

Antioxidative Property of β-chitooligosaccharides Against H2O2-induced Oxidative Stress

이승재,황진우,안혜원,박표잠,성시흥,김은경 한국키틴키토산학회 2009 한국키틴키토산학회지 Vol.14 No.4

In this study, we investigated the protective effect of β-chitooligosaccharides (β-COSs) against hydrogen peroxide (H2O2)- induced oxidative stress, and its effect on antioxidative enzyme activity in vitro. We prepared three kinds of β-COSs with different molecular weights: higher molecular weights (HMWβ-COSs: 50~10 kDa), medium molecular weights (MMWβ- COSs: 10~5 kDa), and lower molecular weight (LMWβ-COSs: below 5 kDa). The results showed that MMWβ-COSs exhibited the most preventive property of cell apoptosis induced by H2O2. The protective effect of MMWβ-COSs on free radical-induced DNA damage exhibited 62% at 1.0 mg/mL. In addition, antioxidative enzyme levels in cultured liver cells were increased in the presence of MMWβ-COSs. These results indicate that MMWβ-COSs shows potent antioxidative activity. In this study, we investigated the protective effect of β-chitooligosaccharides (β-COSs) against hydrogen peroxide (H2O2)- induced oxidative stress, and its effect on antioxidative enzyme activity in vitro. We prepared three kinds of β-COSs with different molecular weights: higher molecular weights (HMWβ-COSs: 50~10 kDa), medium molecular weights (MMWβ- COSs: 10~5 kDa), and lower molecular weight (LMWβ-COSs: below 5 kDa). The results showed that MMWβ-COSs exhibited the most preventive property of cell apoptosis induced by H2O2. The protective effect of MMWβ-COSs on free radical-induced DNA damage exhibited 62% at 1.0 mg/mL. In addition, antioxidative enzyme levels in cultured liver cells were increased in the presence of MMWβ-COSs. These results indicate that MMWβ-COSs shows potent antioxidative activity.

Effect of Analytical Parameters of Gel Permeation Chromatography on Molecular Weight Measurements of Urea-Formaldehyde Resins¹

Bora Jeong,Byung-dae Park 한국목재공학회 2017 목재공학 Vol.45 No.4

As the molecular weight (MW) of urea-formaldehyde (UF) resins had a great impact on their properties, this work was conducted to study effect of analytical parameters of gel permeation chromatography (GPC) on the MW measurement of UF resins. GPC parameters such as flow rate, column, detector temperature, and sample injection temperature were selected to compare number-average molecular weight (Mn), weight-average molecular weight (Mw), molecular weight distribution (MWD) and polydispersity index (PDI) of two UF resins with different viscosities. As expected, UF resin with higher viscosity resulted in greater Mn and Mw than those of low viscosity UF resin. When the flow rate increased, both Mn and Mw of UF resins decreased and MWD became narrower. By contrast, both Mn and Mw increased and MWD became wide when the column, detector, and sample injection temperature increased. The column, detector, and sample injection temperature of 50℃ at a flow rate of 0.5 mℓ/min resulted in the highest MW and broadest MWD for the GPC analysis. These results suggest that the apparent molecular size or a hydrodynamic radius of UF resin molecules dissolved in the mobile phase affect to Mn, Mw and MWD.

Effects of Molecular Weight of Polyvinylidene Fluoride Binder on Electrochemical Performances of Organic Electric Double-Layer Capacitors

Jihoon Yoo(유지훈),Inchan Yang(양인찬),Myung-Soo Kim(김명수),Ji Chul Jung(정지철) 한국고분자학회 2019 폴리머 Vol.43 No.6

본 논문에서는 바인더가 유기계 전기이중층 커패시터(EDLCs)의 전기화학적 성질에 미치는 영향을 조사하기 위하여 플루오르화 폴리비닐리덴(polyvinylidene fluoride, PVDF) 바인더의 분자량을 다르게 하여 EDLC를 조립한 후 다양한 전기화학적 특성 분석을 실시하였다. 특성 분석 결과, 낮은 분자량의 PVDF를 사용하여 조립된 EDLC는 높은 분자량의 PVDF를 사용하여 조립된 EDLC보다 낮은 저항 및 높은 용량 특성을 나타냈으나 충-방전이 진행되는 동안 활물질과 도전재 사이의 구조가 높은 분자량의 PVDF를 사용하여 조립된 EDLC에 비해 느슨해져 결과적으로 낮은 수명을 나타내었다. 따라서 높은 성능을 갖는 EDLC를 제조하기 위해서는 적절한 바인더 분자량이 요구된다. Herein, we assembled electric double-layer capacitor (EDLCs) electrodes with polyvinylidene fluoride (PVDF) as the binder. The effect of the molecular weight of PVDF on the electrochemical properties of the EDLCs were investigated by various characterization tools. The EDLCs assembled using PVDF with low molecular weight showed relatively good capacitance compared to those assembled using PVDF with high molecular weight owing to their low resistance. However, in long-term durability experiments, EDLCs assembled using PVDF with high molecular weights showed higher durability than EDLCs assembled using PVDF with low molecular weights. To investigate the underlying reasons, field emission-scanning electron microscopy (FE-SEM) was applied. Although all prepared EDLC electrodes showed tightly packed morphologies before charge–discharge process was conducted, morphologies of electrodes using low molecular weight PVDF were gradually loosed as charge–discharge process was conducted. As a result, an appropriate binder molecular weight is required to prepare EDLC with high performances.

Effect of silk fibroin molecular weight on physical property of silk hydrogel

Kim, H.H.,Song, D.W.,Kim, M.J.,Ryu, S.J.,Um, I.C.,Ki, C.S.,Park, Y.H. Elsevier 2016 Polymer Vol.90 No.-

<P><B>Abstract</B></P> <P>Silk hydrogel has recently received great attention for its excellent biocompatibility. The property of silk hydrogel is, however, not only hardly controlled but very limited due to non-variability of silk fibroin (SF) molecule. In this study, alkaline hydrolysis was utilized to manipulate the silk hydrogel properties. By regulating the hydrolysis time (10–180 min), a broad molecular weight range of SF was obtained (263.1–82.7 kDa) Gel point increased with a decrease of SF molecular weight. The change of molecular weight of SF also greatly affected the physical properties (i.e., swelling ratio, shear modulus, transparency) as well as cell adhesion of SF hydrogels. As a result of structural analysis, the molecular weight of SF played a crucial role in the construction of microscopic structure of SF hydrogel. These findings indicate that SF hydrogels of variable physical properties can be fabricated based on molecular weight control for diverse purposes in biomedical engineering.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Molecular weight of SF critically affected the physical properties of SF hydrogel. </LI> <LI> Microscopic structure and secondary structure of SF hydrogel affected the optical property of SF hydrogel. </LI> <LI> SF hydrogel with different molecular weight could be utilized for diverse purpose in biomedical engineering. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Significance of the Molecular Weight and Degree of N-Deacetylation of Chitosan-Oligosaccharides on the Biological Applications

( Jae Kweon Park ),( Hang Soo Jo ),( Choul Gyun Lee ),( Yong Il Park ) 한국키틴키토산학회 2010 한국키틴키토산학회지 Vol.15 No.4

In order to investigate the potential of chitosan-oligosaccharides (CTSN-OS) prepared by enzymatic digestion of high molecular-weight chitosan, the antiviral effect of CTSN-OS was studied. Their molecular weights and degree of N-deacetylation were primarily determined by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). The CTSN-OS were then further fractionated into two groups by gel-filtration: 1) oligosaccharides with no N-acetyl groups, consisting of (GlcN)n, n=3-5 (trimer; 31.7%, tetramer; 37.7%, and pentamer; 18.6%, hereafter referred to as COS, and 2) those with more N-acetylated residues, consisting of a mixture of (GlcN)n, n>5 and (GlcNAc)n, n=1-3 in various ratios, hereafter referred to as HOS. The HOS showed higher molecular weights than COS. The inhibitory effects of CTSN-OS, COS and HOS on neuraminidase and antiviral activity against herpes simplex virus type-1 (HSV-1) were investigated in vitro. The results demonstrated that HOS showed lower inhibitory activities toward both neuraminidase and HSV-1 than inhibitory activities of CTSN-OS that showed toward neuraminidase and HSV-1 whereas COS showed similar effects on both neuraminidase and HSV- 1 to those of CTSN-OS, respectively. CTSN-OS or COS has not shown the significant inhibitory activities though, these results suggest that lower molecular weights and/or a lower degree of N-acetylation of chitosan-oligosaccharides are important factors giving rise to their antiviral activities. In addition, in order to elucidate the biological function and utilization of CTSN-OS, transformation of the green algae Haematococcus lacustris with a phytoene desaturase gene involved in astaxanthin biosynthesis prior to establish the condition for si-RNA transformation to elucidate the pathway was performed using CTSN-OS and/or high molecular weight chitosan as a gene carrier. As the results of comparison, CTSN-OS that has shown the higher DNA binding capacity than the capacity with high molecular weight chitosan did affect on cell growth and the production of extracellular materials instead showing the efficiency of the transformation in the present study.

Plasmid DNA의 세포전이에 대한 PEI 분자량의 영향

이경만,김인숙,이용복,신상철,오인준 한국약제학회 2005 Journal of Pharmaceutical Investigation Vol.35 No.1

Polyethylenimine (PEI) has been used as cationic polymers for efficient gene transfer without the need for endosomolytic agents. Various kinds of PEIs with different molecular weight were tested in order to investigate the effects of the molecular weight of PEI on the transfection efficiency and cell cytotoxicity. The [3-galactosidase expression (pCMV-13-gal) plasmid was used as a model DNA. Complex formation between PEI and pDNA was assessed by 1% agarose gel electrophoresis method. Particle size and zeta-potential of complexes were determined by electrophoretic light scattering spectrometer. In vino transfection efficiency was assayed by measuring (3-galactosidase activity. Cell cytotoxicity was deter-mined by MTT assay. Particle sizes of the complexes became smaller on increasing molecular weights of PEI and N/P ratios. Surface potential of complexes was increased as the molecular weight of PEI increased. Transfection efficiency of pCMV-[3-gal on the HEK 293 cells was greatest with PEI 25 K system but having the lowest cell viability. PEI with high molecular weight showed higher transfection efficiency and cell viability than PEI with low molecular weight.

Calculation of molecular weight distribution using extended Cole-Cole model and quadratic mixing rule

이정행,김상모,조광수 한국유변학회 2021 Korea-Australia rheology journal Vol.33 No.1

We suggest a numerical method to calculate molecular weight distribution from linear viscoelastic data. The calculation method consists of three components: (1) a viscoelastic model of a monodisperse polymer as a function of molecular weight; (2) the mixing rule connecting viscoelastic data of monodisperse and polydisperse polymers through molecular weight distribution; (3) an algorithm which calculates the molecular weight distribution from the chosen mixing rule. Since we cannot measure the relaxation modulus of all monodisperse samples, we need an accurate monodisperse model for any molecular weight. It is known that a dynamic test is more reliable than a relaxation test, while the mixing rule needs relaxation modulus. Hence, we should have a smart numerical method that can convert dynamic data to relaxation modulus with the minimum conversion error. If we use the numerical method, then we have to generate numerical data from the model. Then it takes quite a long time. On the other hand, if we have a monodisperse model with the analytical relaxation spectrum, then calculation time can be reduced dramatically. Since the conversion from relaxation modulus to dynamic modulus suffers from smaller errors than the reverse conversion because of ill-posedness of the interconversion, the analytical conversion can be implemented more quickly at an acceptable level of errors. This paper proposes a new method satisfying the requirements.

폴리에틸렌글리콜의 분자량이 공중합 폴리에스터의 열적 특성 및 알칼리 가수분해에 미치는 영향

김영준,지민호,이은희,최진욱,노동현,노환권,백두현,Kim, Young-June,Jee, Min-Ho,Lee, Eun-Hee,Choi, Jin-Uk,Noh, Dong-Hyun,Rho, Hwan-Kwon,Baik, Doo-Hyun 한국섬유공학회 2012 한국섬유공학회지 Vol.49 No.1

Copolyesters containing sodium sulfonate group and poly(ethylene glycol) (PEG) were synthesized with various molecular weight of PEG. The selected molecular weights of PEG were 1000, 2000, 4000, 6000, and 16000. The thermal properties and the crystallization behaviors of the copolyesters were investigated by using differential scanning calorimeter (DSC). Alkaline hydrolysis of the copolyesters was studied as a function of the treatment time. The melting temperatures and the heats of fusion of the copolyesters increased with an increase in the PEG molecular weight, while the weight reduction rate of copolyesters in an alkaline solution decreased with an increase in the PEG molecular weight. At the same PEG content in copolyesters, hard segment length increases with the PEG molecular weight, which was thought to be the most important factor that determines the thermal properties and the alkaline hydrolysis behavior.

Dehydration and Drying Characteristics of Gingers Using Dehydrating Agent by Dextrose Equivalent and Molecular Weight Condition

이현석,권기현,김병삼,정진웅,김종훈,성정민 한국식품저장유통학회 2010 한국식품저장유통학회지 Vol.17 No.6

We examined variations in ginger dehydration and recovery rate upon use of dextrose of different equivalence values. The dehydration rate varied with dextrose equivalent and the dehydration rate increased as the equivalence value increased. Both dehydration and recovery rates varied with dextrose molecular weight. Moisture content was lowest in samples prepared by freeze-drying, and neither dextrose equivalent nor molecular weight affected moisture level. Upon color analysis, ginger dried using dextrose varying in equivalence and molecular weight was similar in color to the original material, unlike ginger dried by other methods. Hot-air-dried ginger scored lowest in all sensory tests, compared with ginger prepared by molecular press dehydration using dextrose varying in equivalence and molecular weight. With respect to the appearance of ginger, freeze-dried samples were optimal, but molecular press dehydration yielded samples that scored best upon overall evaluation. When all quality evaluation items were taken together, molecular press dehydration resulted in a better quality product than the older hot-air or freeze-drying methods.